Bieser, John O. (2115 Banks Houston, TX, 77098, US)
| 1. | A carpet comprising a primary backing material having a face and a back side, a plurality of fibers attached to the primary backing material and extending from the face of the primary backing material and exposed at the back side of the primary backing material, an adhesive backing material and an optional secondary backing material adjacent to the adhesive backing material, wherein at least one of the plurality of fibers, the primary backing material, the adhesive backing material or the optional secondary backing material is comprised of at least one substantially random interpolymer. |
| 2. | The carpet of Claim 1 wherein the adhesive backing material comprises; (A) one or more substantially random interpolymers, comprising; (1) polymer units derived from; (i) at least one vinyl or vinylidene aromatic monomer, or (ii) at least one hindered aliphatic or cycloaliphatic vinyl or vinylidene monomer, or (iii) a combination of at least one aromatic vinyl or vinylidene monomer and at least one aliphatic or cycloaliphatic vinyl or vinylidene monomer, and (2) polymer units derived from ethylene and or at least one C320 aolefin; and optionally (3) polymer units derived from one or more ethylenically unsaturated polymerizable monomers other than those of (1) and (2); and optionally (B) at least one polymer other than that of Component A; and optionally (C) one or more fillers; and optionally (D) one or more other additives. |
| 3. | The carpet of Claim 2 wherein (I) said substantially random interpolymer, Component A, is present in an amount from about 5 to 100 wt percent (based on the combined weights of Components A B, C and D) and has an I2 of about 0.01 to about 1000 g/10 min and an M/M,, of about 1.5 to about 20, and comprises; (1) from about 2 to about 65 mol percent of polymer units derived from; (i) at least one vinyl or vinylidene aromatic monomer, or (ii) at least one hindered aliphatic or cycloaliphatic vinyl or vinylidene monomer, or (iii) a combination of at least one aromatic vinyl or vinylidene monomer and at least one hindered aliphatic or cycloaliphatic vinyl or vinylidene monomer, and (2) from about 35 to about 98 mol percent of polymer units derived from at least one of ethylene and/or a C320 aolefin; and (3) from 0 to about 20 mol percent of polymer units derived from one or more of said ethylenically unsaturated polymerizable monomers other than those derived from (1) and (2); and (II) Component B is present in an amount from 0 to about 95 wt percent (based on the combined weights of Components A, B, C and D); and (III) said filler, Component C is present in an amount from 0 to about 95 wt percent (based on the combined weights of Components A, B, C and D); and (IV) said other additive, Component D is selected from the group consisting of tackifiers, oils, waxes and plasticizers. |
| 4. | The carpet of Claim 2 wherein; (I) said substantially random interpolymer Component (A) is present in an amount of about 40 to 100 wt percent (based on the combined weights of Components A, B, C and D) and has an I2 of about 0.1 to about 1000 g/10 min and an M, lMn of about 1.8 to about 10; and comprises (1) from about 20 to about 60 mol percent of polymer units derived from; (i) said vinyl or vinylidene aromatic monomer represented by the following formula; wherein R'is selected from the group of radicals consisting of hydrogen and alkyl radicals containing three carbons or less, and Ar is a phenyl group or a phenyl group substituted with from 1 to 5 substituents selected from the group consisting of halo, C,,alkyl, andC, 4haloalkyl; or (ii) said sterically hindered aliphatic or cycloaliphatic vinyl or vinylidene monomer is represented by the following general formula; wherein A'is a sterically bulky, aliphatic or cycloaliphatic substituent of up to 20 carbons, R'is selected from the group of radicals consisting of hydrogen and alkyl radicals containing from 1 to about 4 carbon atoms, preferably hydrogen or methyl; each R2 is independently selected from the group of radicals consisting of hydrogen and alkyl radicals containing from 1 to about 4 carbon atoms, preferably hydrogen or methyl; or alternatively R'and A'together form a ring system; and (2) from about 40 to about 80 mol percent of polymer units derived from ethylene and/or said aolefin which comprises at least one of propylene, 4methyllpentene, butene1, hexene1 or octene1; and (3) said ethylenically unsaturated polymerizable monomers other than those derived from (1) and (2) comprises norbornene, or a CI10 alkyl or C6, 0 aryl substituted norbornene; II) Component B is present in amount from about 0 to about 60 wt percent (based on the combined weights of Components A, B, C and D) and comprises one or more of a) a homogeneous interpolymer, b) a heterogeneous interpolymer; c) a thermoplastic olefin, d) a styrenic block copolymer, e) a styrenic homoor copolymer, f) an elastomer, g) an engineering thermoplastic, and (III) said filler Component C is present in an amount from 0 to about 80 wt percent (based on the combined weights of Components A, B, C and D), and comprises one or more of calcium carbonate, alumina trihydrate, talc, wood flour, sawdust, glass fiber, barium sulfate, marble dust, or nanofillers. |
| 5. | The carpet of Claim 2 wherein; (I) said substantially random interpolymer, Component (A), is present in an amount from about 60 to 100 wt percent (based on the combined weights of Components A, B, C and D) and has an I2 of about 1 to about 50 g/10 min and an M,M. from about 2 to about 5; and comprises (1) from about 30 to about 50 mol percent of polymer units derived from; i) said vinyl aromatic monomer which comprises styrene, a methyl styrene, ortho, meta, and paramethylstyrene, and the ring halogenated styrenes, or ii) said aliphatic or cycloaliphatic vinyl or vinylidene monomers which comprises 5ethylidene2norbornene or 1vinylcyclohexene, 3vinylcyclohexene, and 4 vinylcyclohexene; (2) from about 50 to about 70 mol percent of polymer units derived from ethylene, or ethylene and said aolefin, which comprises ethylene, or ethylene and at least one of propylene, 4methyll pentene, butene1, hexene1 or octene1; and (3) said ethylenically unsaturated polymerizable monomers other than those derived from (1) and (2) is norbornene; II) Component B is present in amount from about 0 to about 40 wt percent (based on the combined weights of Components A, B, C and D) and comprises one or more of ; a) a substantially linear ethylene/aolefin interpolymer; b) a heterogeneous ethylene/C3C8 aolefin interpolymer; c) an ethylene/propylene rubber (EPM), ethylene/propylene diene monomer terpolymer (EPDM), isotactic polypropylene; d) a styrene/ethylenebutene copolymer, a styrene/ethylene propylene copolymer, a styrene/ethylenebutene/styrene (SEBS) copolymer, a styrene/ethylenepropylene/styrene (SEPS) copolymer, e) the acrylonitrilebutadienestyrene (ABS) polymers, styreneacrylonitrile (SAN), polystyrene, high impact polystyrene, f) polyisoprene, polybutadiene, natural rubbers, ethylene/propylene rubbers, ethylene/propylene diene (EPDM) rubbers, styrene/butadiene rubbers, thermoplastic polyurethanes, g) poly (methylmethacrylate), polyester, nylon6, nylon6,6, poly (acetal); poly (amide), poly (arylate), poly (carbonate), poly (butylene) and polybutylene, polyethylene terephthalates; and (III) said filler Component C is present in an amount from 0 to about 80 wt percent (based on the combined weights of Components A, B, C and D), and comprises one or more of calcium carbonate, alumina trihydrate, talc, and barium sulfate. |
| 6. | The carpet of Claim 5 wherein Component AI (i) is styrene, Component A2 is ethylene, and Component C if present is calcium carbonate. |
| 7. | The carpet of Claim 5 wherein Component Al (i) is styrene; and Component A2 is ethylene and at least one of propylene, 4methyllpentene, butene1, hexene1 or octene1; and Component C if present is calcium carbonate. |
| 8. | The carpet of Claim 1 wherein said substantially random interpolymer is cross linked. |
| 9. | A method of making a carpet, the carpet comprising a primary backing material having a face and a back side, a plurality of fibers attached to the primary backing material and extending from the face of the primary backing material and exposed at the back side of the primary backing material, an adhesive backing material disposed on the exposed fibers extending from the back side of the primary backing material wherein the adhesive backing material comprises; (A) at least one substantially random interpolymer, which comprises; (1) polymer units derived from; (i) at least one vinyl or vinylidene aromatic monomer, or (ii) at least one hindered aliphatic or cycloaliphatic vinyl or vinylidene monomer, or (iii) a combination of at least one aromatic vinyl monomer and at least one aliphatic or cycloaliphatic vinyl or vinylidene monomer, and (2) polymer units derived from ethylene and or at least one C320 aolefin; and optionally (3) polymer units derived from one or more ethylenically unsaturated polymerizable monomers other than those of (1) and (2); and optionally (B) at least one polymer other than that of Component A; and optionally (C) one or more fillers. |
| 10. | The method of Claim 9 wherein said adhesive backing material is disposed on said exposed fibers by extrusion coating. |
| 11. | The method of Claim 10 wherein Component A1 (i) is styrene, Component A2 is ethylene, and Component C if present is calcium carbonate. |
| 12. | The method of Claim 9 wherein said adhesive backing material is disposed on said exposed fibers using a hot melt adhesive process. |
| 13. | The method of Claim 12 wherein Component Al (i) is styrene, Component A2 is ethylene, and Component C if present is calcium carbonate. |
| 14. | The method of Claim 9 wherein said adhesive backing material is disposed on said exposed fibers by forming a sheet from said adhesive backing material and laminating said sheet on to said exposed fibers. |
| 15. | The method of Claim 14 wherein said sheet comprising a substantially random interpolymer is formed by an extrusion, pressing or calendering process. |
| 16. | The method of Claim 14 wherein Component Al (i) is styrene, Component A2 is ethylene, and Component C if present is calcium carbonate. |
| 17. | The method of Claim 15 wherein Component A l (i) is styrene, Component A2 is ethylene, and Component C if present is calcium carbonate. |
The present invention pertains to any carpet constructed with a primary backing material, and includes tufted carpet and non-tufted carpet such as needle punched carpet. Tufted carpets are composite structures which include yarn (which is also known as a fiber bundle), a primary backing material having a face surface and a back surface, an adhesive backing material and, optionally, a secondary backing material.
To form the face surface of tufted carpet, yarn is tufted through the primary backing material such that the longer length of each stitch extends through the face surface of the primary backing material. Typically, the primary backing material is made of a woven or non-woven material such as a thermoplastic polymer, most commonly polypropylene.
The face of a tufted carpet can generally be made in three ways. First, for loop pile carpet, the yarn loops formed in the tufting process are left intact. Second, for cut pile carpet, the yarn loops are cut, either during tufting or after, to produce a pile of single yarn ends instead of loops. Third, some carpet styles include both loop and cut pile. One variety of this hybrid is referred to as tip-sheared carpet where loops of differing lengths are tufted followed by shearing the carpet at a height so as to produce a mix of uncut, partially cut, and completely cut loops. Alternatively, the tufting machine can be configured so as to cut only some of the loops, thereby leaving a
pattern of cut and uncut loops. Whether loop, cut, or a hybrid, the yarn on the back side of the primary backing material comprises tight, unextended loops.
The combination of tufted yarn and a primary backing material without the application of an adhesive backing material or secondary backing material is referred to in the carpet industry as raw tufted carpet or greige goods. Greige goods become finished tufted carpet with the application of an adhesive backing material and an optional secondary backing material to the back side of the primary backing material.
Finished tufted carpet can be prepared as broad-loomed carpet in rolls typically 6 or 12 feet wide. Alternatively, carpet can be prepared as carpet tiles, typically 18 inches square in the United States and 50 cm. square elsewhere.
The adhesive backing material is applied to the back face of the primary backing material to affix the yarn to the primary backing material. Most frequently, the adhesive backing material is applied as a single coating or layer. The extent or tenacity to which the yarn is affixed is referred to as tuft lock or tuft bind strength. Carpets with sufficient tuft bind strength exhibit good wear resistance and, as such, have long service lives. Also, the adhesive backing material should substantially penetrate the yarn (fiber bundle) exposed on the backside of the primary backing material and should substantially consolidate individual fibers within the yarn. Good penetration of the yarn and consolidation of fibers yields good abrasion resistance. Moreover, in addition to good tuft bind strength and abrasion resistance, the adhesive material should also impart or allow good flexibility to the carpet in order to facilitate easy installation.
Known adhesive backing materials include curable latex, urethane or vinyl systems, with latex systems being the most common. Conventional latex systems are low viscosity, aqueous compositions that are applied at high carpet production rates and offer good fiber-to-backing adhesion, tuft bind strength and adequate flexibility. The latex backing system is usually heavily filled with an inorganic filler such as calcium carbonate or Aluminum Trihydrate and includes other ingredients such as antioxidants,
antimicrobials, flame retardants, smoke suppressants, wetting agents, and froth aids.
Typically, the latex adhesive is applied as a coating to the bottom surface of the griege goods which are then passed through an oven to drive off excess water, thus bonding the face fibers to the primary backing.
The above-described method for making carpet is used in the preparation of the vast majority of all carpet made in the United States, however this method has the disadvantage that it requires a drying step and thus an oven to dry the latex polymer binder. The drying step increases the cost of the carpet and limits production speed. In addition, such latex systems do not provide a good moisture barrier.
In view of these drawbacks, some in the carpet industry have begun seeking suitable replacements for conventional latex adhesive backing systems. One alternative is the use of urethane adhesive backing systems. In addition to providing adequate adhesion to consolidate the carpet, urethane backings generally exhibit good flexibility and barrier properties and, when foamed, can eliminate the need for separate underlayment padding (that is, can constitute a direct glue-down unitary backing system). However, urethane backing systems also have important drawbacks, including their relatively high cost and demanding curing requirements which necessitate application at slow carpet production rates relative to latex systems.
Thermoplastic polyolefins such as low density polyethylene (LDPE) have also been suggested as adhesive backing materials due in part to their low cost, good moisture stability and no-cure requirements. However, using polyolefins to replace latex adhesive backings can also present difficulties. For example, US Patent No.
5,240,530 teaches that typical polyolefin resins possess inadequate adhesion for use in carpet construction. Additionally, relative to latex and urethane systems, typical polyolefins have relatively high application viscosity's and relatively high thermal requirements. That is, they are characterized by relatively high melt viscosity's and high recrystallization or solidification temperatures relative to the typical aqueous
viscosity's and cure temperature requirements characteristic of latex and other cured (thermosetting) systems. Even elastomeric polyolefins, that is polyolefins having low crystallinities, generally have relatively high viscosity's and relatively high recrystallization temperatures. High recrystallization temperatures result in relatively short molten times during processing and, combined with high melt viscosity's, can make it difficult to achieve adequate penetration of the yarn, especially at conventional adhesive backing application rates.
While unformulated high pressure low density polyethylene (LDPE) can be applied by a conventional extrusion coating technique, the resulting resins typically have poor flexibility which can result in excessive carpet stiffness. Conversely, those typical polyolefins that have improved flexibility, such as ultra low density polyethylene (ULDPE) and ethylene/propylene interpolymers, still do not possess sufficient flexibility, have excessively low melt strengths and/or tend to draw resonate during extrusion coating.
One method for overcoming the heating and curing steps required in latex and urethane systems respectively, and the viscosity and recrystallization deficiencies of ordinary polyolefins is to formulate the polyolefin resin backing material as a hot melt adhesive. Hot-melt adhesives are amorphous polymers that soften and flow sufficiently to wet and penetrate the backing surfaces and tuft stitches of carpets upon application of sufficient heat. Furthermore, hot-melt adhesives tend to adhere to the backing surfaces and/or tuft stitches. That is, hot-melt adhesives stick to backing surfaces and tuft stitches.
Hot melt adhesive formulations typically comprise low molecular weight polyolefins with waxes, tackifiers, various flow modifiers and/or other elastomeric materials. Ethylene/vinyl acetate (EVA) copolymers and other polyolefins compositions, have been used in formulated hot melt adhesive backing compositions.
For example, US Patent No. 3,982,051, by Taft et al. discloses that a composition
comprising an ethylene/vinyl acetate copolymer, atactic polypropylene and vulcanized rubber is useful as a hot melt carpet backing adhesive. Similarly, US Patent No.
5,128,183 (C. Peoples et al., assigned to Exxon Research & Engineering Co., and Collins and Aikman Corporation) is directed to highly flexible compositions of matter useful in the preparation of carpet backing comprising thermoplastic resin compositions including copolymers of ethylene and unsaturated esters of lower carboxylic acids, such as vinyl esters and/or lower alkyl acrylates, in mixture with olefinic elastomers and substantial amounts of filler. Other examples of flexible polyolefin hot melt adhesive backing materials based on EVA and waxes are disclosed in U. S. Patents 3,745,054; and 3,914,489.
Application of a hot-melt composition is generally accomplished by passing the bottom surface of the griege goods over an applicator roll positioned in a reservoir containing the hot-melt composition in a molten state. A doctor blade is ordinarily employed to control the amount of adhesive which is transferred from the application roll to the bottom surface of the structure. After application of the hot-melt composition to the bottom surface of the griege goods, and prior to cooling, the secondary backing, if desired, is brought into contact with the bottom surface, and the resulting structure is then passed through nip rolls and heated. Known techniques for enhancing the penetration of hot melt adhesive backing compositions through the yarn include applying pressure while the greige good is in contact with rotating melt transfer rollers as described, for example, in U. S. Patent No. 3, 551,231. As such, polyolefin hot melt systems are typically applied to primary backings by relatively slow, less efficient techniques such as by the use of heated doctor blades or rotating melt transfer rollers.
Unfortunately, typical hot melt systems based on EVA and other copolymers of ethylene and unsaturated comonomers can require considerable formulating and yet often yield inadequate tuft bind strengths.
However, the most significant deficiency of typical hot melt systems are their melt strengths which are generally too low to permit application by a direct extrusion
coating technique in which the polymer composition, usually in pellet-form, is heated in an extruder to a temperature above its melt temperature and then forced through a slot die to form a semi-molten or molten polymer web. The semi-molten or molten polymer web is continuously drawn down onto a continuously fed greige good to coat the backside of the greige good with the polymer composition.
To overcome extrusion coating difficulties, ordinary polyolefins with sufficient flexibility can be applied by lamination techniques to insure adequate yarn-to-backing adhesion. US Patent No. 4,844,765 (R. A. Reith, assigned to Amoco Co.) is directed to lamination of a tufted, primary carpet backing to a secondary backing is conducted using a composite hot melt adhesive in sheet form. Also disclosed are hot melt adhesive compositions suitable for use in sheet form in such a process. However, lamination techniques are typically expensive and can result in extended production rates relative to direct extrusion coating techniques.
Another known technique for enhancing the effectiveness of hot melt systems involve using pre-coat systems. For example, U. S. Patents 3,684,600; and 3,745,054 describe the application of low viscosity aqueous pre-coats to the back surface of the primary backing material prior to the application of a hot melt adhesive composition. The hot melt adhesive backing systems disclosed in these patents are derived from multi-component formulations based on functional ethylene polymers such as, for example, ethylene/ethyl acrylate (EEA) and ethylene/vinyl acetate (EVA) copolymers.
Another technique for carpet manufacture is known as fibrous incorporation.
The process consists of incorporating a fiber, or nonwoven. or woven polymeric product into a carpet structure, and then heating the structure above the softening point of the polymer to allow it to flow and consolidate the structure together. The fibrous incorporation can include the inclusion of polymeric staple fiber or continuous filament into the face fiber yarn, the inclusion of a non-woven fabric or fibers
comprising a polymeric product onto the primary backing, or the inclusion of a polymeric non-woven fabric or fiber onto the secondary backing.
Finally, independent of their method of fabrication, certain carpet applications also require that the carpet material also act as a sound deadening layer. US Patent No. 4,379,190 (T. T. Schenck), US Patent No. 4,438 228 (T. T. Schenck) and US Patent No. 4,403,007 (M. C. Coughlin) all assigned to E. 1. Du Pont de Nemours Company are directed to filled thermoplastic compositions useful as sound deadening sheeting for automotive carpet.
However, there remains a need for a thermoplastic carpet backing system which exhibits good tuft bind, abrasion resistance, lamination strength and demonstrates improved flexibility and good conformability over contoured or uneven surfaces, has good layflat properties even at high filler levels, has good coating performance at higher molecular weight, or lower melt indices and also requires no adhesion promoter for glue down with common carpet glues, and where no coupling agent is required for filled products and finally has improved sound deadening and dampening and electrostatic dissipation properties, while being prepared by a simple extrusion coating technique.
The present invention pertains to improved carpets and carpet backing comprising an adhesive backing material which comprises; (A) at least one substantially random interpolymer, which comprises; (1) polymer units derived from; (i) at least one vinyl or vinylidene aromatic monomer, or (ii) at least one hindered aliphatic or cycloaliphatic vinyl or vinylidene monomer, or (iii) a combination of at least one aromatic vinyl or vinylidene monomer and at least one aliphatic or cycloaliphatic vinyl or vinylidene monomer, and
(2) polymer units derived from ethylene and or at least one C3, o a-olefin; and optionally (3) polymer units derived from one or more ethylenically unsaturated polymerizable monomers other than those of (1) and (2); and optionally (B) at least one polymer other than that of Component A; and optionally (C) one or more fillers; and optionally (D) one or more other additives.
The invention also comprises a method of making a carpet, the carpet comprising a primary backing material having a face and a back side, a plurality of fibers attached to the primary backing material and extending from the face of the primary backing material and exposed at the back side of the primary backing material, an adhesive backing material disposed on the exposed fibers extending from the back side of the primary backing material wherein the adhesive backing material comprises; (A) at least one substantially random interpolymer, which comprises; (1) polymer units derived from; (i) at least one vinyl or vinylidene aromatic monomer, or (ii) at least one hindered aliphatic or cycloaliphatic vinyl or vinylidene monomer, or (iii) a combination of at least one aromatic vinyl or vinylidene monomer and at least one aliphatic or cycloaliphatic vinyl or vinylidene monomer, and (2) polymer units derived from ethylene and or at least one C320 a-olefin; and optionally (3) polymer units derived from one or more ethylenically unsaturated polymerizable monomers other than those of (1) and (2); and optionally (B) at least one polymer other than that of Component A; and optionally (C) one or more fillers.
The present invention provides advantages for both carpet tile and broadloom carpet over coated carpet made with polyolefin based backing systems. These improvements include: 1) good coating performance at higher molecular weight, or lower melt indices, 2) no adhesion promoter for glue down with common carpet glues, 3) improved flexibility, 4) good conformability over contoured or uneven surfaces, 5) good layflat properties even at high filler levels, 6) no coupling agent required for filled products, 7) improved sound deadening and/or dampening properties, and 8) good electrostatic dissipation properties.
Definitions All references herein to elements or metals belonging to a certain Group refer to the Periodic Table of the Elements published and copyrighted by CRC Press, Inc., 1989. Also any reference to the Group or Groups shall be to the Group or Groups as reflected in this Periodic Table of the Elements using the IUPAC system for numbering groups.
Any numerical values recited herein include all values from the lower value to the upper value in increments of one unit provided that there is a separation of at least 2 units between any lower value and any higher value. As an example, if it is stated that the amount of a component or a value of a process variable such as, for example, temperature, pressure, and time is, for example, from 1 to 90, preferably from 20 to 80, more preferably from 30 to 70, it is intended that values such as 15 to 85,22 to 68,43 to 51,30 to 32 etc. are expressly enumerated in this specification. For values which are less than one, one unit is considered to be 001,0.01 or 0.1 as appropriate.
These are only examples of what is specifically intended and all possible combinations of numerical values between the lowest value and the highest value enumerated are to be considered to be expressly stated in this application in a similar manner.
The term"carpet component"is used herein to refer separately to carpet fiber bundles, the primary backing material, the adhesive backing material and the optional secondary backing material.
The term"extrusion coating"is used herein in its conventional sense to refer to an extrusion technique wherein a polymer composition usually in pellet-form is heated in an extruder to a temperature elevated above its melt temperature and then forced through a slot die to form a semi-molten or molten polymer web. The semi-molten or molten polymer web is continuously drawn down onto a continuously fed greige good to coat the backside of the greige good with the polymer composition. Extrusion coating is distinct from a lamination technique.
The term"lamination technique"is used herein in its conventional sense refer to applying adhesive backing materials to greige goods by first forming the adhesive backing material as a solidified or substantially solidified film or sheet and thereafter, in a separate processing step, reheating or elevating the temperature of the film or sheet before applying it to the back surface of the primary backing material.
The term"heat content"is used herein to refer to the mathematical product of the heat capacity and specific gravity of a filler. Fillers characterized as having high heat content are used in specific embodiments of the present invention to extend the solidification or molten time of adhesive backing materials. The Handbook for Chemical Technicians, Howard J. Strauss and Milton Kaufmann, McGraw Hill Book Company, 1976, Sections 1-4 and 2-1 provides information on the heat capacity and specific gravity of select mineral fillers. The fillers suitable for use in the present invention do not change their physical state (that is, remain a solid material) over the extrusion coating processing temperature ranges of the present invention. Preferred high heat content fillers possess a combination of a high specific gravity and a high heat capacity.
The term''implosionagent"is used herein to refer to the use of conventional blowing agents or other compounds which out-gas or cause out-gassing when activated by heat, usually at some particular activation temperature. In the present invention, implosion agents are used to implode or force adhesive backing material into the free space of yarn or fiber bundles.
The term"processing material"is used herein to refer to substances such as spin finishing waxes, equipment oils, and sizing agents which can interfere with the adhesive or physical interfacial interactions of adhesive backing materials. Processing materials can be removed or displaced by a scouring or washing technique of the present invention whereby improved mechanical bonding is accomplished.
The terms"polypropylene carpet"and"polypropylene greige goods"are used herein to mean a carpet or greige goods substantially comprised of polypropylene fibers, irrespective of whether the primary backing material for the carpet or greige good is comprised of polypropylene or some other material.
The terms"nylon carpet"and"nylon greige goods"are used herein to mean a carpet or greige goods substantially comprised of nylon fibers, irrespective of whether the primary backing material for the carpet or greige good is comprised of nylon or some other material.
The term"fibrous incorporation"as employed herein means a process wherein a fiber. or non-woven, or woven product comprising one or more substantially random interpolymers is incorporated into a carpet structure, followed by heating the structure above the softening point of the substantially random interpolymers to allow it to flow and consolidate the structure together. The fibrous incorporation can include the inclusion of stable fiber or continuous filament comprising one or more substantially random interpolymers into the face fiber yarn, the inclusion of a non-woven fabric or fibers comprising one or more substantially random interpolymers onto the primary
backing, or the inclusion of a non-woven fabric or fiber comprising one or more substantially random interpolymers onto the secondary backing.
The term"hydrocarbyl"as employed herein means any aliphatic, cycloaliphatic, aromatic, aryl substituted aliphatic, aryl substituted cycloaliphatic, aliphatic substituted aromatic, or aliphatic substituted cycloaliphatic groups.
The term"hydrocarbyloxy"means a hydrocarbyl group having an oxygen linkage between it and the carbon atom to which it is attached.
The term"copolymer"as employed herein means a polymer wherein at least two different monomers are polymerized to form the copolymer.
The term"interpolymer"is used herein to indicate a polymer wherein at least two different monomers are polymerized to make the interpolymer. This includes copolymers, terpolymers, etc.
The invention especially covers a carpet comprising at least one substantially random interpolymer. In one embodiment, the invention also covers the method of extrusion coating at least one substantially random interpolymer containing material as a carpet backing at coating weights of 1 to 100 oz/yd', (0. 03-3.4 k) dependent on carpet market segment or application. The substantially random interpolymer- containing layer can be extrusion coated directly on to the backside of carpet, or a number of layers can be applied via co-extrusion or multiple pass extrusion. The substantially random interpolymer can also be applied on top of other backing layers comprised of such materials as another polyolefin, latex, or PVC. The substantially random interpolymer-containing layer may be foamed with a chemical blowing agent or by direct gas injection, and may be cross-linked by peroxide, silane, or radiation methods. In the invention, other materials can also be applied on top of the substantially random interpolymer-containing layer. Extrusion die configurations
include: monolayer, single die co-extrusion, and multiple lip co-extrusion. Additional equipment includes: preheater, wind/unwind stations, chill roll, and pressure roll.
This invention also covers methods for applying the substantially random interpolymer-containing materials as carpet backing as a hot melt adhesive. For hot melt adhesives, a formulation containing the substantially random interpolymer can be prepared and applied with hot melt application technology.
This invention also covers methods for applying the substantially random interpolymer-containing materials by lamination of a substantially random interpolymer-containing sheet formed by extrusion, calendering or pressing. For lamination, the substantially random interpolymer-containing sheet can be manufactured using the aforementioned methods and heat laminated to the back side of carpet using a roll mill, calender line, IR oven, through air oven, or press.
This invention also covers methods for applying the substantially random interpolymer-containing materials by fibrous incorporation of the substantially random interpolymer-containing material. For fibrous incorporation, the substantially random interpolymer-containing fiber, non-woven fabric, or woven fabric can be added to the backside of carpet by combining with the primary backing via needle punching, lamination, or weaving. This combination can occur before or after tufting of carpet face yarn into the primary backing. Subsequent heating of the carpet allows consolidation. Also, subsequent substantially random interpolymer-containing fiber could be added to the yarn to serve as a bond fiber.
The term"substantially random" (in the substantially random interpolymer comprising polymer units derived from one or more a-olefin monomers with one or more vinyl or vinylidene aromatic monomers and/or sterically hindered aliphatic or cycloaliphatic vinyl or vinylidene monomers) as used herein means that the distribution of the monomers of said interpolymer can be described by the Bernoulli statistical
model or by a first or second order Markovian statistical model, as described by J. C.
Randall in POLYMER SEQUENCE DETERMINATION. Carbon-13 NMR Method.
Academic Press New York, 1977, pp. 71-78. Preferably, substantially random interpolymers do not contain more than 15 percent of the total amount of vinyl aromatic monomer in blocks of vinyl aromatic monomer of more than 3 units. More preferably, the interpolymer is not characterized by a high degree of either isotacticity or syndiotacticity. This means that in the carbon~'3 NMR spectrum of the substantially random interpolymer the peak areas corresponding to the main chain methylene and methine carbons representing either meso diad sequences or racemic diad sequences should not exceed 75 percent of the total peak area of the main chain methylene and methine carbons.
The interpolymers used to prepare the carpets of the present invention include the substantially random interpolymers prepared by polymerizing i) ethylene and/or one or more a-olefin monomers and ii) one or more vinyl or vinylidene aromatic monomers and/or one or more sterically hindered aliphatic or cycloaliphatic vinyl or vinylidene monomers, and optionally iii) other polymerizable ethylenically unsaturated monomer (s). Suitable a-olefins include for example, a-olefins containing from 3 to 20, preferably from 3 to 12, more preferably from 3 to about 8 carbon atoms. Particularly suitable are ethylene, propylene, butene-l, 4-methyl-1-pentene, hexene-1 or octene-1 or ethylene in combination with one or more of propylene, butene-1,4-methyl-1-pentene, hexene-l or octene-1. These a-olefins do not contain an aromatic moiety.
Other optional polymerizable ethylenically unsaturated monomer (s) include norbornene and C,, 0 alkyl or C6, 0 aryl substituted norbornenes, with an exemplary interpolymer being ethylene/styrene/norbornene.
Suitable vinyl or vinylidene aromatic monomers which can be employed to prepare the interpolymers include, for example, those represented by the following formula:
wherein R'is selected from the group of radicals consisting of hydrogen and alkyl radicals containing from 1 to about 4 carbon atoms, preferably hydrogen or methyl; each R'is independently selected from the group of radicals consisting of hydrogen and alkyl radicals containing from 1 to about 4 carbon atoms, preferably hydrogen or methyl; Ar is a phenyl group or a phenyl group substituted with from 1 to 5 substituents selected from the group consisting of halo, C,-,-alkyl, and C, 4-haloalkyl; and n has a value from zero to about 4, preferably from zero to 2, most preferably zero. Exemplary vinyl aromatic monomers include styrene, vinyl toluene, a-methylstyrene, t-butyl styrene, chlorostyrene, including all isomers of these compounds. Particularly suitable such monomers include styrene and lower alkyl-or halogen-substituted derivatives thereof. Preferred monomers include styrene, a-methyl styrene, the lower alkyl- (C,- C4) or phenyl-ring substituted derivatives of styrene, such as for example, ortho-, meta-, and para-methylstyrene, the ring halogenated styrenes, para-vinyl toluene or mixtures thereof. A more preferred aromatic vinyl monomer is styrene.
By the term"sterically hindered aliphatic or cycloaliphatic vinyl or vinylidene compounds", it is meant addition polymerizable vinyl or vinylidene monomers corresponding to the formula: wherein A'is a sterically bulky, aliphatic or cycloaliphatic substituent of up to 20 carbons, R'is selected from the group of radicals consisting of hydrogen and alkyl radicals containing from 1 to about 4 carbon atoms, preferably hydrogen or methyl; each R'is independently selected from the group of radicals consisting of hydrogen and alkyl radicals containing from 1 to about 4 carbon atoms, preferably hydrogen or methyl; or alternatively R'and A'together form a ring system. Preferred aliphatic or
cycloaliphatic vinyl or vinylidene compounds are monomers in which one of the carbon atoms bearing ethylenic unsaturation is tertiary or quaternary substituted. Examples of such substituents include cyclic aliphatic groups such as cyclohexyl, cyclohexenyl, cyclooctenyl, or ring alkyl or aryl substituted derivatives thereof, tert-butyl, and norbornyl. Most preferred aliphatic or cycloaliphatic vinyl or vinylidene compounds are the various isomeric vinyl-ring substituted derivatives of cyclohexene and substituted cyclohexenes, and 5-ethylidene-2-norbornene. Especially suitable are 1-, 3- , and 4-vinylcyclohexene. Simple linear ct-olefins including for example, a-olefins containing from 3 to about 20 carbon atoms such as ethylene, propylene, butene-1,4- methyl-1-pentene, hexene-1 or octene-1 are not examples of sterically hindered aliphatic or cycloaliphatic vinyl or vinylidene compounds.
The substantially random interpolymers may be modified by typical grafting, hydrogenation, functionalizing, or other reactions well known to those skilled in the art.
The polymers may be readily sulfonated or chlorinated to provide functionalized derivatives according to established techniques. The substantially random interpolymers may also be modified by various chain extending or cross-linking processes including, but not limited to peroxide-, silane-, sulfur-, radiation-, or azide- based cure systems. A full description of the various cross-linking technologies is described in copending U. S. Patent Application No's 08/921,641 and 08/921,642 both filed on August 27,1997. Dual cure systems, which use a combination of heat, moisture cure, and radiation steps, may be effectively employed. Dual cure systems are disclosed and claimed in U. S. Patent Application Serial No. 536,022, filed on September 29,1995, in the names of K. L. Walton and S. V. Karande. For instance, it may be desirable to employ peroxide crosslinking agents in conjunction with silane crosslinking agents, peroxide crosslinking agents in conjunction with radiation, sulfur- containing crosslinking agents in conjunction with silane crosslinking agents, etc. The substantially random interpolymers may also be modified by various cross-linking processes including, but not limited to the incorporation of a diene component as a termonomer in its preparation and subsequent cross linking by the aforementioned
methods and further methods including vulcanization via the vinyl group using sulfur for example as the cross linking agent.
One method of preparation of the substantially random interpolymers includes polymerizing a mixture of polymerizable monomers in the presence of one or more metallocene or constrained geometry catalysts in combination with various cocatalysts, as described in EP-A-0,416,815 by James C. Stevens et al. and US Patent No. by Francis J. Timmers. Preferred operating conditions for such polymerization reactions are pressures from atmospheric up to 3000 atmospheres and temperatures from-30°C to 200°C. Polymerizations and unreacted monomer removal at temperatures above the autopolymerization temperature of the respective monomers may result in formation of some amounts of homopolymer polymerization products resulting from free radical polymerization.
Examples of suitable catalysts and methods for preparing the substantially random interpolymers are disclosed in U. S. Application Serial No. 702,475, filed May 20,1991 (EP-A-514,828); as well as U. S. Patents: 5,055,438; 5,096,867; 5,064,802; 5,189,192; 5,321,106; 5,347,024; 5,350,723; 5,374,696; 5,399,635; 5,470,993; and 5,721,18.
The substantially random oc-olefin/vinyl aromatic interpolymers can also be prepared by the methods described in JP 07/278230 employing compounds shown by the general formula where Cp'and Cp2 are cyclopentadienyl groups, indenyl groups, fluorenyl groups, or substituents of these, independently of each other; R'and R2 are hydrogen atoms, halogen atoms, hydrocarbon groups with carbon numbers of 1-12, alkoxyl groups, or aryloxyl groups, independently of each other; M is a group IV metal, preferably Zr or
Hf, most preferably Zr; and R3 is an alkylene group or silanediyl group used to cross- link Cp'and Cp2).
The substantially random a-olefin/vinyl aromatic interpolymers can also be prepared by the methods described by John G. Bradfute et al. (W. R. Grace & Co.) in WO 95/32095; by R. B. Pannell (Exxon Chemical Patents, Inc.) in WO 94/00500; and in Plastics Technology, p. 25 (September 1992).
Also suitable are the substantially random interpolymers which comprise at least one a-olefin/vinyl aromatic/vinyl aromatic/a-olefin tetrad disclosed in U. S.
Application No. 08/708,869 filed September 4,1996 and WO 98/09999 both by Francis J. Timmers et al. These interpolymers contain additional signals in their carbon-13 NMR spectra with intensities greater than three times the peak to peak noise. These signals appear in the chemical shift range 43.70-44.25 ppm and 38. 0-38.5 ppm.
Specifically, major peaks are observed at 44.1,43.9, and 38.2 ppm. A proton test NMR experiment indicates that the signals in the chemical shift region 43.70-44.25 ppm are methine carbons and the signals in the region ppm are methylene carbons.
It is believed that these new signals are due to sequences involving two head-to- tail vinyl aromatic monomer insertions preceded and followed by at least one a-olefin insertion, for example an ethylene/styrene/styrene/ethylene tetrad wherein the styrene monomer insertions of said tetrads occur exclusively in a 1,2 (head to tail) manner. It is understood by one skilled in the art that for such tetrads involving a vinyl aromatic monomer other than styrene and an a-olefin other than ethylene that the ethylene/vinyl aromatic monomer/vinyl aromatic monomer/ethylene tetrad will give rise to similar carbon-13 NMR peaks but with slightly different chemical shifts.
These interpolymers can be prepared by conducting the polymerization at temperatures of from about-30°C to about 250°C in the presence of such catalysts as those represented by the formula
wherein: each Cp is independently, each occurrence, a substituted cyclopentadienyl group s-bond to M; E is C or Si; M is a group IV metal, preferably Zr or Hf, most preferably Zr; each R is independently, each occurrence, H, hydrocarbyl, silahydrocarbyl, or hydrocarbylsilyl, containing up to about 30 preferably from 1 to about 20 more preferably from 1 to about 10 carbon or silicon atoms ; each R'is independently, each occurrence, H, halo, hydrocarbyl, hyrocarbyloxy, silahydrocarbyl, hydrocarbylsilyl containing up to about 30 preferably from 1 to about 20 more preferably from 1 to about 10 carbon or silicon atoms or two R'groups together can be a C 1-10 hydrocarbyl substituted 1, 3-butadiene; m is 1 or 2; and optionally, but preferably in the presence of an activating cocatalyst. Particularly, suitable substituted cyclopentadienyl groups include those illustrated by the formula: wherein each R is independently, each occurrence, H, hydrocarbyl, silahydrocarbyl, or hydrocarbylsilyl, containing up to about 30 preferably from 1 to about 20 more preferably from 1 to about 10 carbon or silicon atoms or two R groups together form a divalent derivative of such group. Preferably, R independently each occurrence is (including where appropriate all isomers) hydrogen, methyl, ethyl, propyl, butyl, pentyl, hexyl, benzyl, phenyl or silyl or (where appropriate) two such R groups are linked together forming a fused ring system such as indenyl, fluorenyl, tetrahydroindenyl, tetrahydrofluorenyl, or octahydrofluorenyl.
Particularly preferred catalysts include, for example, racemic- (dimethylsilanediyl)-bis- (2-methyl-4-phenylindenyl) zirconium dichloride, racemic- (dimethylsilanediyl)-bis- (2-methyl-4-phenylindenyl) zirconium 1,4-diphenyl-1, 3- butadiene, racemic- (dimethylsilanediyl)-bis- (2-methyl-4-phenylindenyl) zirconium di-
C 1-4 alkyl, racemic- (dimethylsilanediyl)-bis- (2-methyl-4-phenylindenyl) zirconium di- C 1-4 alkoxide, or any combination thereof.
It is also possible to use the following titanium-based constrained geometry catalysts, N- (l, l-dimethylethyl)-l, l-dimethyl-1- (1,2,3,4,5-n)-1,5,6,7-tetrahydro-s- indacen-1-yl silanaminato (2-)-N] titanium dimethyl; (1-indenyl) (tert- butylamido) dimethyl- silane titanium dimethyl; ((3-tert-butyl) (1, 2, 3,4,5-P)-1- indenyl) (tert-butylamido) dimethylsilane titanium dimethyl; and ( (3-iso- propyl) (1,2, 3,4,5-P)-1-indenyl) (tert-butyl amido) dimethylsilane titanium dimethyl, or any combination thereof.
Further preparative methods for the interpolymers used in the present invention have been described in the literature. Longo and Grassi (Makromol. Chem., Volume 191, pages 2387 to 2396 [1990]) and D'Anniello et al. (Journal of Applied Polymer Science, Volume 58, pages 1701-1706 [1995]) reported the use of a catalytic system based on methylalumoxane (MAO) and cyclopentadienyltitanium trichloride (CpTiCI3) to prepare an ethylene-styrene copolymer. Xu and Lin (Polymer Preprints, Am. Chem.
Soc., Div. Polvm. Chem.) Volume 35, pages 686,687 [1994]) have reported copolymerization using a MgCI2/TiCI4/NdCI3/Al (iBu) 3 catalyst to give random copolymers of styrene and propylene. Lu et al (Journal of Applied Polymer Science, Volume 53, pages 1453 to 1460 [1994]) have described the copolymerization of ethylene and styrene using a TiCI4/NdCIJ MgCI2/AI (Et) 3 catalyst. Sernetz and Mulhaupt, (Macromol. Chem. Phvs., v. 197, pp. 1071-1083,1997) have described the influence of polymerization conditions on the copolymerization of styrene with ethylene using Me2Si (Me4Cp) (N-tert-butyl) TiCI,/methylaluminoxane Ziegler-Natta catalysts. Copolymers of ethylene and styrene produced by bridged metallocene catalysts have been described by Arai, Toshiaki and Suzuki (Polvmer Preprints, Am.
Chem. Soc.. Div. Polym. Chem.) Volume 38, pages 349,350 [1997]) and in United States patent number 5,652,315, issued to Mitsui Toatsu Chemicals, Inc. The manufacture of a-olefin/vinyl aromatic monomer interpolymers such as
propylene/styrene and butene/styrene are described in United States patent number 5,244,996, issued to Mitsui Petrochemical Industries Ltd or United States patent number also issued to Mitsui Petrochemical Industries Ltd or as disclosed in DE 197 11 339 A1 to Denki Kagaku Kogyo KK.
While preparing the substantially random interpolymer, an amount of atactic vinyl aromatic homopolymer may be formed due to homopolymerization of the vinyl aromatic monomer at elevated temperatures. The presence of vinyl aromatic homopolymer is in general not detrimental for the purposes of the present invention and can be tolerated. The vinyl aromatic homopolymer may be separated from the interpolymer, if desired, by extraction techniques such as selective precipitation from solution with a non solvent for either the interpolymer or the vinyl aromatic homopolymer. For the purpose of the present invention it is preferred that no more than 30 weight percent, preferably less than 20 weight percent based on the total weight of the interpolymers of atactic vinyl aromatic homopolymer is present.
Blend Compositions Comprising the Substantiallv Random Interpolvmers The present invention also provides carpets prepared from blends of the substantially random a-olefin/vinyl or vinylidene interpolymers with one or more other polymer components which span a wide range of compositions.
The other polymer component of the blend can include, but is not limited to, one or more of an engineering thermoplastic, an a-olefin homopolymer or interpolymer, a thermoplastic olefin, a styrenic block copolymer, a styrenic homo-or copolymer, or an elastomer.
Engineering Thermoplastics The third edition of the Kirk-Othmer Encyclopedia of Science and Technology (Volume 9, p 118-137) defines engineering plastics as thermoplastic resins, neat or unreinforced or filled, which maintain dimensional stability and most mechanical
properties above 100°C and below 0°C. The terms"engineering plastics"and "engineering thermoplastics", can be used interchangeably. Engineering thermoplastics include acetal and acrylic resins, polyamides (for example nylon-6, nylon 6,6,), polyimides, polyetherimides, cellulosics, polyesters, poly (arylate), aromatic polyesters, poly (carbonate), poly (butylene) and polybutylene and polyethylene terephthalates, liquid crystal polymers, and selected polyolefins, blends, or alloys of the foregoing resins, and some examples from other resin types (including for example polyethers) high temperature polyolefins such as polycyclopentanes, its copolymers, and polymethylpentane.).
An especially preferred engineering thermoplastic are the acrylic resins which derive from the peroxide-catalyzed free radical polymerization of methyl methacrylate (MMA). As described by H. Luke in Modem Plastics Encyclopedia, 1989, pps 20-21, MMA is usually copolymerized with other acrylates such as methyl-or ethyl acrylate using four basic polymerization processes, bulk, suspension, emulsion and solution.
Acrylics can also be modified with various ingredients including butadiene, vinyl and butyl acrylate.
The a-Olefin Homopolvmers and Interpolvmers The a-olefin homopolymers and interpolymers comprise polypropylene, propylene/C4-C20 a-olefin copolymers, polyethylene, and ethylene/C3-C20 a-olefin copolymers, the interpolymers can be either heterogeneous ethylene/a-olefin interpolymers or homogeneous ethylene/a-olefin interpolymers, including the substantially linear ethylene/a-olefin interpolymers. Also included are aliphatic a- olefins having from 2 to 20 carbon atoms and containing polar groups. Suitable aliphatic a-olefin monomers which introduce polar groups into the polymer include, for example, ethylenically unsaturated nitriles such as acrylonitrile, methacrylonitrile, ethacrylonitrile, etc.; ethylenically unsaturated anhydrides such as maleic anhydride; ethylenically unsaturated amides such as acrylamide, methacrylamide etc.; ethylenically unsaturated carboxylic acids (both mono-and
difunctional) such as acrylic acid and methacrylic acid, etc.; esters (especially lower, for example C,-C6, alkyl esters) of ethylenically unsaturated carboxylic acids such as methyl methacrylate, ethyl acrylate, hydroxyethylacrylate, n-butyl acrylate or methacrylate, 2-ethyl-hexylacrylate, or ethylene-vinyl acetate copolymers EVA) etc.; ethylenically unsaturated dicarboxylic acid imides such as N-alkyl or N-aryl maleimides such as N-phenyl maleimide, etc. Preferably such monomers containing polar groups are acrylic acid, vinyl acetate, maleic anhydride and acrylonitrile.
Heterogeneous interpolymers are differentiated from the homogeneous interpolymers in that in the latter, substantially all of the interpolymer molecules have the same ethylene/comonomer ratio within that interpolymer, whereas heterogeneous interpolymers are those in which the interpolymer molecules do not have the same ethylene/comonomer ratio. The term"broad composition distribution"used herein describes the comonomer distribution for heterogeneous interpolymers and means that the heterogeneous interpolymers have a"linear" fraction and that the heterogeneous interpolymers have multiple melting peaks (that is, exhibit at least two distinct melting peaks) by DSC. The heterogeneous interpolymers have a degree of branching less than or equal to 2 methyls/1000 carbons in about 10 percent (by weight) or more, preferably more than about 15 percent (by weight), and especially more than about 20 percent (by weight). The heterogeneous interpolymers also have a degree of branching equal to or greater than 25 methyls/1000 carbons in about 25 percent or less (by weight), preferably less than about 15 percent (by weight), and especially less than about 10 percent (by weight).
The Ziegler catalysts suitable for the preparation of the heterogeneous component of the current invention are typical supported, Ziegler-type catalysts.
Examples of such compositions are those derived from organomagnesium compounds, alkyl halides or aluminum halides or hydrogen chloride, and a transition metal compound. Examples of such catalysts are described in U. S. Pat Nos.
4,314,912 (Lowery, Jr. et al.), 4,547,475 (Glass et al.), and 4,612,300 (Coleman, III).
Suitable catalyst materials may also be derived from a inert oxide supports and transition metal compounds. Examples of such compositions are described in U. S.
Patent No. 5,420,090 (Spencer, et al).
The heterogeneous polymer component can be a homolymer of ethylene or an a-olefin preferably polyethylene or polypropylene, or, preferably, an interpolymer of ethylene with at least one C3-C20 a-olefin and/or C4-C 18 dienes. Heterogeneous copolymers of ethylene, and propylene, 1-butene, 1-hexene, 4-methyl-1-pentene and 1- octene are especially preferred.
The relatively recent introduction of metallocene-based catalysts for ethylene/a- olefin polymerization has resulted in the production of new ethylene interpolymers known as homogeneous interpolymers.
The homogeneous interpolymers useful for forming the compositions described herein have homogeneous branching distributions. That is, the polymers are those in which the comonomer is randomly distributed within a given interpolymer molecule and wherein substantially all of the interpolymer molecules have the same ethylene/comonomer ratio within that interpolymer. The homogeneity of the polymers is typically described by the SCBDI (Short Chain Branch Distribution Index) or CDBI (Composition Distribution Branch Index) and is defined as the weight percent of the polymer molecules having a comonomer content within 50 percent of the median total molar comonomer content. The CDBI of a polymer is readily calculated from data obtained from techniques known in the art, such as, for example, temperature rising elution fractionation (abbreviated herein as"TREF") as described, for example, in Wild et al, Journal of Polymer Science, Poly. Phvs. Ed., Vol. 20, p. 441 (1982), in U. S. Patent 4,798,081 (Hazlitt et al.), or as is described in USP 5,008,204 (Stehling). The technique for calculating CDBI is described in USP 5,322,728 (Davey et al.) and in USP 5,246,783 (Spenadel et al.). or in U. S. Patent 5,089,321 (Chum et al.). The SCBDI or
CDBI for the homogeneous interpolymers used in the present invention is preferably greater than about 30 percent, especially greater than about 50 percent.
The homogeneous interpolymers used in this invention essentially lack a measurable"high density"fraction as measured by the TREF technique (that is, the homogeneous ethylene/a-olefin interpolymers do not contain a polymer fraction with a degree of branching less than or equal to 2 methyls/1000 carbons). The homogeneous interpolymers also do not contain any highly short chain branched fraction (that is, they do not contain a polymer fraction with a degree of branching equal to or more than 30 methyls/1000 carbons).
The substantially linear ethylene/a-olefin polymers and interpolymers of the present invention are also homogeneous interpolymers but are further herein defined as in U. S. Patent No. 5,272,236 (Lai et al.), and in U. S. Patent No. 5,272,872. Such polymers are unique however due to their excellent processability and unique rheological properties and high melt elasticity and resistance to melt fracture. These polymers can be successfully prepared in a continuous polymerization process using the constrained geometry metallocene catalyst systems.
The term"substantially linear"ethylene/a-olefin interpolymer means that the polymer backbone is substituted with about 0.01 long chain branches/1000 carbons to about 3 long chain branches/1000 carbons, more preferably from about 0.01 long chain branches/1000 carbons to about 1 long chain branches/1000 carbons, and especially from about 0.05 long chain branches/1000 carbons to about 1 long chain branches/1000 carbons.
Long chain branching is defined herein as a chain length of at least one carbon more than two carbons less than the total number of carbons in the comonomer, for example, the long chain branch of an ethylene/octene substantially linear ethylene interpolymer is at least seven (7) carbons in length (that is, 8 carbons less 2 equals 6
carbons plus one equals seven carbons long chain branch length). The long chain branch can be as long as about the same length as the length of the polymer back-bone.
Long chain branching is determined by using 13C nuclear magnetic resonance (NMR) spectroscopy and is quantified using the method of Randall (Rev. Macromol. Chem.
Phys., C29 (2&3), p. 285-297). Long chain branching, of course, is to be distinguished from short chain branches which result solely from incorporation of the comonomer, so for example the short chain branch of an ethylene/octene substantially linear polymer is six carbons in length, while the long chain branch for that same polymer is at least seven carbons in length.
The catalysts used to prepare the homogeneous interpolymers for use as blend components in the present invention are metallocene catalysts. These metallocene catalysts include the bis (cyclopentadienyl)-catalyst systems and the mono (cyclopentadienyl) Constrained Geometry catalyst systems (used to prepare the substantially linear ethylene/a-olefin polymers). Such constrained geometry metal complexes and methods for their preparation are disclosed in U. S. Application Serial No. 545,403, filed July 3,1990 (EP-A-416,815); U. S. Application Serial No. 547,718, filed July 3,1990 U. S. Application Serial No. 702,475, filed May 20, 1991 (EP-A-514,828); as well as US-A-5,055,438, US-A-5,057,475, US-A-5,096,867, US-A-5,064,802, US-A-5,132,380, US-A-5,721,185, US-A-5, 374,696 and US-A- 5,470,993.
In EP-A 418,044, published March 20,1991 (equivalent to U. S. Serial No.
07/758,654) and in U. S. Serial No. 07/758,660 certain cationic derivatives of the foregoing constrained geometry catalysts that are highly useful as olefin polymerization catalysts are disclosed and claimed. In U. S. Serial Number 720,041, filed June 24, 1991, certain reaction products of the foregoing constrained geometry catalysts with various boranes are disclosed and a method for their preparation taught and claimed. In US-A 5,453,410 combinations of cationic constrained geometry catalysts with an alumoxane were disclosed as suitable olefin polymerization catalysts.
The homogeneous polymer component can be an ethylene or a-olefin homopolymer preferably polyethylene or polypropylene, or, preferably, an interpolymer of ethylene with at least one C3-C20 a-olefin and/or C4-C 18 dienes.
Homogeneous copolymers of ethylene, and propylene, 1-butene, 1-hexene, 4-methyl-1- pentene and 1-octene are especially preferred.
Thermoplastic Olefins Thermoplastic olefins (TPOs) are generally produced from propylene homo-or copolymers, or blends of an elastomeric material such as ethylene/propylene rubber (EPM) or ethylene/propylene diene monomer terpolymer (EPDM) and a more rigid material such as isotactic polypropylene. Other materials or components can be added into the formulation depending upon the application, including oil, fillers, and cross- linking agents. Generally, TPOs are characterized by a balance of stiffness (modulus) and low temperature impact, good chemical resistance and broad use temperatures.
Because of features such as these, TPOs are used in many applications, including automotive facia and instrument panels, and also potentially in wire and cable The polypropylene is generally in the isotactic form of homopolymer polypropylene, although other forms of polypropylene can also be used (for example, syndiotactic or atactic). Polypropylene impact copolymers (for example, those wherein a secondary copolymerization step reacting ethylene with the propylene is employed) and random copolymers (also reactor modified and usually containing 1.5-7 percent ethylene copolymerized with the propylene), however, can also be used in the TPO formulations disclosed herein. In-reactor TPO's can also be used as blend components of the present invention. A complete discussion of various polypropylene polymers is contained in Modem Plastics Encyclopedia/89, mid October 1988 Issue, Volume 65, Number 11, pp. 86-92. The molecular weight of the polypropylene for use in the present invention is conveniently indicated using a melt flow measurement according to ASTM D-1238, Condition 230°C/2.16 kg (formerly known as"Condition (L)"and also known as 12). Melt flow rate is
inversely proportional to the molecular weight of the polymer. Thus, the higher the molecular weight, the lower the melt flow rate, although the relationship is not linear. The melt flow rate for the polypropylene useful herein is generally from about 0.1 grams/10 minutes (g/10 min) to about 35 g/10 min, preferably from about 0.5 g/10 min to about 25 g/10 min, and especially from about 1 g/10 min to about 20 g/10 min.
Styrenic Block Copolvmers Also included are block copolymers having unsaturated rubber monomer units including, but not limited to, styrene-butadiene (SB), styrene-isoprene (SI), styrene- butadiene-styrene (SBS), styrene-isoprene-styrene (SIS), a-methylstyrene-butadiene-a- methylstyrene and a-methylstyrene-isoprene-a-rnethylstyrene.
The styrenic portion of the block copolymer is preferably a polymer or interpolymer of styrene and its analogs and homologs including a-methylstyrene and ring-substituted styrenes, particularly ring-methylated styrenes. The preferred styrenics are styrene and a-methylstyrene, and styrene is particularly preferred.
Block copolymers with unsaturated rubber monomer units may comprise homopolymers of butadiene or isoprene or they may comprise copolymers of one or both of these two dienes with a minor amount of styrenic monomer.
Preferred block copolymers with saturated rubber monomer units comprise at least one segment of a styrenic unit and at least one segment of an ethylene-butene or ethylene-propylene copolymer. Preferred examples of such block copolymers with saturated rubber monomer units include styrene/ethylene-butene copolymers, styrene/ethylene-propylene copolymers, styrene/ethylene-butene/styrene (SEBS) copolymers, styrene/ethylene-propylene/styrene (SEPS) copolymers.
Styrenic Homo-and Copolymers
In addition to the block copolymers are the various styrene homopolymers and copolymers and rubber modified styrenics. These include polystyrene, high impact polystyrene and copolymers such as acrylonitrile-butadiene-styrene (ABS) polymers, styrene-acrylonitrile (SAN).
Elastomers The elastomers include, but are not limited to, rubbers such as polyisoprene, polybutadiene, natural rubbers, ethylene/propylene rubbers, ethylene/propylene diene (EPDM) rubbers, styrene/butadiene rubbers, thermoplastic polyurethanes.
The compositions comprising at least one substantially random interpolymer used to prepare the carpets of the present invention in addition to optionally comprising one or more of another polymer components can optionally comprise one or more fillers.
Fillers Also included as a potential component of the polymer compositions used in the present invention are various organic and inorganic fillers, the identity of which depends upon the type of application in the blend is to be utilized. Representative examples of such fillers include organic and inorganic fibers such as those made from asbestos, boron, graphite, ceramic, glass, metals (such as stainless steel) or polymers (such as aramid fibers) talc, carbon black, carbon fibers, calcium carbonate, alumina trihydrate, glass fibers, marble dust, cement dust, clay, feldspar, silica or glass, fumed silica, alumina, magnesium oxide, magnesium hydroxide, antimony oxide, zinc oxide, barium sulfate, aluminum silicate, calcium silicate, titanium dioxide, titanates, aluminum nitride, B203, nickel powder or chalk.
Other representative organic or inorganic, fiber or mineral, fillers include carbonates such as barium, calcium or magnesium carbonate; fluorides such as calcium or sodium aluminum fluoride; hydroxides such as aluminum hydroxide; metals such as
aluminum, bronze, lead or zinc; oxides such as aluminum, antimony, magnesium or zinc oxide, or silicon or titanium dioxide; silicates such as asbestos, mica, clay (kaolin or calcined kaolin), calcium silicate, feldspar, glass (ground or flaked glass or hollow glass spheres or microspheres or beads, whiskers or filaments), nepheline, perlite, pyrophyllite, talc or wollastonite; sulfates such as barium or calcium sulfate; metal sulfides; cellulose, in forms such as wood or shell flour; calcium terephthalate; and liquid crystals, or ground up plastrics such as thermoset polymers. Mixtures of more than one such filler may be used as well.
More preferably the filler is selected from the group consisting of barium sulfate, talc and calcium carbonate (CaCO3) with calcium carbonate being most preferred.
These fillers could be employed in amounts from 0 to about 95, preferably from 0 to about 80, more preferably from 0 to about 60 percent by weight based on the weight of the polymer or polymer blend.
Other Additives Additives such as antioxidants (for example, hindered phenols such as, for example, IrganoxT 1010, and phosphites, for example, IrgafosTM 168, (both are registered trademarks of, and supplied by Ciba-Geigy Corporation, NY), u. v. stabilizers (including Tinuvin'328 and Chimassorb 944, both are registered trademarks of, and supplied by Ciba-Geigy Corporation, NY), cling additives (for example, polyisobutylene), slip agents (such as erucamide and/or stearamide), antiblock additives, antifogging agents, colorants, and pigments can also be included in the interpolymers and/or blends employed to prepare the carpets of the present invention, to the extent that they do not interfere with the properties of the substantially random interpolymers.
Processing aids, which are also referred to herein as plasticizers, are optionally provided to reduce the viscosity of a composition, and include the phthalates, such as dioctyl phthalate and diisobutyl phthalate, natural oils such as lanolin, and paraffin, naphthenic and aromatic oils obtained from petroleum refining, and liquid resins from rosin or petroleum feedstocks. Suitable modifiers which can be employed herein as the plasticizer include at least one plasticizer selected from the group consisting of phthalate esters, trimellitate esters, benzoates. adipate esters, epoxy compounds, phosphate esters (triaryl, trialkyl, mixed alkyl aryl phosphates), glutarates and oils.
Particularly suitable phthalate esters include, for example, dialkyl C4-C 18 phthalate esters such as diethyl, dibutyl phthalate, diisobutyl phthalate, butyl 2-ethylhexyl phthalate, dioctyl phthalate, diisooctyl phthalate, dinonyl phthalate, diisononyl phthalate, didecyl phthalate, diisodecyl phthalate, diundecyl phthalate, mixed aliphatic esters such as heptyl nonyl phthalate, di (n-hexyl, n-octyl, n-decyl) phthalate (P610), di (n-octyl, n-decyl) phthalate (P810), and aromatic phthalate esters such as diphenyl phthalate ester, or mixed aliphatic-aromatic esters such as benzyl butyl phthalate or any combination thereof.
Exemplary classes of oils useful as processing aids include white mineral oil (such as Kaydol oil (available from Witco), and Shellflex 371 naphthenic oil (available from Shell Oil Company). Another suitable oil is TufloTM oil (available from Lyondell).
Antifogging or antistatic agents can be added to the films and sheets of the present invention to increase surface conductivity and prevention of water droplet formation and attraction of dust and dirt on the film surface. These antifogging agents include, but are not limited to, glycerol mono-stearate, glycerol mono-oleate, lauric diphthalamides, ethoxylated amines, ethoxylated esters, and other additives known in the industry.
Tackifiers can also be added to the polymer compositions used to prepare the carpets of the present invention in order to alter the Tg and/or melt viscosity and thus extend the available application temperature window of the carpet.
Examples of the various classes of tackifiers include, but are not limited to, aliphatic resins, polyterpene resins, hydrogenated resins, mixed aliphatic- aromatic resins, styrene/a-methylene styrene resins, pure monomer hydrocarbon resin, hydrogenated pure monomer hydrocarbon resin, modified styrene copolymers, pure aromatic monomer copolymers, and hydrogenated aliphatic hydrocarbon resins. Exemplary aliphatic resins include those available under the trade designations Escortez, Piccotac, Mercures, Wingtack, Hi-RezTM, Quintone, Tackirol, etc. Exemplary polyterpene resins include those available under the trade designations Nierez, Piccolyte, Wingtack, Zonarez TM, etc. Exemplary hydrogenated resins include those available under the trade designations Escortez, Arkon TM, Clearon TM, etc. Exemplary mixed aliphatic- aromatic resins include those available under the trade designations Escortez, Regalite, Hercures, ARTM, Imprez, NorsoleneTM M, Marukarez, ArkonTM M, Quinone, Wingtack, etc. One particularly preferred class of tackifiers includes the styrene/a-methylene stryene tackifiers available from Hercules.
Particularly suitable classes of tackifiers include WingtackT 86 and Hercotac 1149, Eastman H-130, and styrene/a-methyl styrene tackifiers.
These additives are employed in functionally equivalent amounts known to those skilled in the art. For example, the amount of antioxidant employed is that amount which prevents the polymer or polymer blend from undergoing oxidation at the temperatures and environment employed during storage and ultimate use of the polymers. Such amount of antioxidants is usually in the range of from 0.01 to 10, preferably from 0.05 to 5, more preferably from 0.1 to 2 percent by weight based upon the weight of the polymer or polymer blend.
Similarly, the amounts of any of the other enumerated additives are the functionally equivalent amounts such as the amount to render the polymer or
polymer blend antiblocking, to produce the desired result, to provide the desired color from the colorant or pigment. Such additives can suitably be employed in the range of from 0.05 to 50, preferably from 0.1 to 35, more preferably from 0.2 to 20 percent by weight based upon the weight of the polymer or polymer blend.
Preparation of the Blends Comprising the Substantiallv Random Interpolvmers The blended polymer compositions used to prepare the carpets of the present invention can be prepared by any convenient method, including dry blending the individual components and subsequently melt mixing or melt compounding in a Haake torque rheometer or by dry blending without melt blending followed by part fabrication, either directly in the extruder or mill used to make the finished article (for example, the automotive part), or by pre-melt mixing in a separate extruder or mill (for example, a Banbury mixer), or by solution blending, or by compression molding, or by calendering.
Preparation of the Carpets of the Present Invention A range of resin properties, processing conditions and equipment configurations have been discovered for extrusion coatable carpet backing systems that deliver performance similar or better than incumbent latex, polyurethane or polyolefin systems.
Typically a tufted carpet is made of a primary backing material with yarn tufted therethrough; an adhesive backing material which is in intimate contact with the back surface of the primary backing material, and substantially encapsulates the yarn, and penetrates the yarn and binds individual carpet fibers; and an optional secondary backing material applied to the back surface of the adhesive backing material.
An extrusion coating line for making a carpet includes an extruder equipped with a slot die, a nip roll, a chill roll, an exhaust hood, a greige good feeder roll, and a pre-heater. The nip roll is preferably equipped with a vacuum slot to draw a vacuum across about 60 degrees or about 17 percent of its circumference and is equipped with a vacuum pump. The slot die dispenses an adhesive backing material in the form of a
semi-molten or molten polymer web onto greige good with the polymer web towards the chill roll and the greige good towards the optional vacuum nip roll. An optional secondary backing material may be applied onto the polymer web. The point where the nip roll and the chill roll are closest to one another is referred to as the nip.
The present invention is useful in producing carpets with face yarn made from various materials including, but not limited to, polypropylene, nylon, wool, cotton, acrylic, polyester and polytrimethylenetheraphthalate (PTT). Most preferably, the yarn used in the present invention is an air entangled 2750 denier polypropylene yarn such as that produced by Shaw Industries, Inc. and sold under the designation"Permacolor 2750 Type 015." The preferred primary backing material comprises a polyolefin, more preferably polypropylene. Most preferably, the primary backing material is a slit film polypropylene sheet such as that sold by AMOCO or Synthetic Industries.
Alternatively, other types of primary backing materials, such as non-woven webs, can also be used. Although other materials, such as polyesters or polyamides can be used for the primary backing material, it is preferred to use a polyolefin as such primary backing materials are typically lower in cost.
The method of tufting or needle-punching the yarn is not deemed critical to the present invention. Thus, any conventional tufting or needle-punching apparatus and stitch patterns can be used. Likewise, it does not matter whether tufted yarn loops are left uncut to produce a loop pile; cut to make cut pile; or cut, partially cut and uncut to make a face texture known as tip sheared. After the yarn is tufted or needle-punched into the primary backing material, the greige good is typically rolled up with the back side of the primary backing material facing outward and held until it is transferred to the backing line.
Extrusion coating configurations include a monolayer T-type die, single-lip die coextrusion coating, dual-lip die coextrusion coating, and multiple stage extrusion coating. Preferably, the extrusion coating equipment is configured to apply a total coating weight of between about 4 and about 30 ounces/yd2 (OSY) (about 141.5 and about 1061.1 cm3/m2), with between about 18 OSY (about 636.7 cm3/m2) and about 22 OSY (about 778.1 cm3/m2), for example, 20 OSY, (707.4 cm3/m2) being most preferred.
Measured another way, the thickness of an unexpanded, collapsed extrusion coated adhesive backing material is in the range from about 6 to about 80 mils, preferably from about 10 to about 60 mils (about 0.25 to about 1.52 mm), more preferably from about 15 to about 50 mils (about 0.38 to about 1.27 mm), and most preferably from about 20 to about 40 mils (about 0.51 to about 1.02 mm).
The line speed of the extrusion process will depend on factors such as the particular polymer being extruded, the exact equipment being used, and the weight of polymer being applied. Preferably, the line speed is between about 18 and about 250 ft./min. (about 5.5 and about 76.2 m/min.), more preferably between about 80 and about 220 ft./min. (about 24.4 and about 67.1 m/min.), most preferably between about 100 and about 200 ft./min. (about 30.5 and about 61 m/min.).
The extrusion coating melt temperature principally depends on the particular polymer being extruded. When using the most preferred substantially linear polyethylene described above, the extrusion coating melt temperature is greater than about 450°F (232°C), preferably greater than or equal to about 500°F (about 260°C), or is between about 450° (about 232°C) and about 650°F (about 343°C), more preferably between about 475° (about 246°C) and about 600°F (about 316°C), most preferably between about 500° and about 550°F (about 260° and about 288°C).
The extruded polymer (s) can either be used neat, or can have one or more additives included. A preferred additive is an inorganic filler, more preferably, an
inorganic filler with a high heat content. Examples of such fillers include, but are not limited to, calcium carbonate, aluminum trihydrate, talc, barite. High heat content fillers are believed to be advantageous in the invention because such fillers allow the extrudate to remain at elevated temperatures longer with the beneficial result of providing enhanced encapsulation and penetration. That is, normally fillers are added to carpet backing materials to merely add bulk (that is as extenders) or to impart insulating and sound dampening characteristics. Inorganic mineral fillers that have high heat contents improve yarn encapsulation and penetration which in turn improves the performance of the abrasion resistance and tuft bind strength of extrusion coated carpet samples. Representative examples of high heat content fillers for use in the present invention include, but are not limited to, limestone (primarily CaCO3), marble, quartz, silica, and barite (primarily BaSO4). The high heat content fillers should be ground or precipitated to a size that can be conveniently incorporated in an extrusion coating melt stream. Suitable particle sizes range from about 1 to about 50 microns.
If a foamed backing is desired on the carpet, a blowing agent can be added to the adhesive backing material and/or the optional secondary backing material. If used, the blowing agents are preferably conventional, heat activated blowing agents such as azodicarbonamide, toluene sulfonyl semicarbazide, and oxy bis (benzene sulfonyl) hydrazide. The amount of blowing agent added depends on the degree of foaming sought. A typical level of blowing agent is between about 0.1 and about 1.0 weight percent.
Implosion in the present invention is accomplished by restricting expansion of the adhesive backing material in the direction opposite the primary backing material during activation of the implosion agent such that the molten polymer is forced into the interior and free space of the yarn or fiber bundles. An imploded adhesive backing material will have a collapsed, non-expanded matrix (relative to a foamed backing) and be of essentially the same thickness (measured from the plane of the back surface of the primary backing material) as would be the case without the use of the implosion agent.
That is, the adhesive backing material layer would be characterized as not being expanded by the implosion agent.
The implosion agent is selected and formulated into the adhesive backing material and extrusion conditions are set such that the activation of the implosion agent occurs at the instant of nip while the adhesive backing material is still semi-molten or molten. With improved yarn penetration accomplished with the use of an implosion agent, the carpet will exhibit comparatively improved abrasion resistance. Thus, the use of an implosion agent can allow the use of polymer compositions having lower molecular weights to provide improved extrusion coatability yet maintain higher abrasion resistance (that is, comparable to adhesive backing materials based on higher molecular weight polymer compositions). An effective amount of implosion agent would be between about 0.1 and about 1.0 weight percent based on the weight of the adhesive backing material.
Conventional blowing agents or any material that ordinarily functions as a blowing agent can be used as an implosion agent in the present invention providing expansion of the adhesive backing material matrix is suitably restricted or confined when the material is activated such that molten polymer is forced into the interior and free space of the yarn or fiber bundles and there is no substantial expansion of the adhesive backing material as a result of having used the implosion agent. However, preferably, an imploded adhesive backing material will be characterized as having a closed cell structure that can be conveniently identified by photomicrographs at 50x magnification.
Other additives can also be included in the adhesive backing material, to the extent that they do not interfere with the enhanced properties discovered by Applicants.
For example, antioxidants such as sterically hindered phenols, sterically hindered amines and phospites may be used. Suitable antioxidants include Irganoxs 1010 from Ciba-Geigy which is a hindered phenol and Irgafoss 168 from Ciba-Geigy which is a
phosphite. Other possible additives include antiblock additives, pigments and colorants, anti-static agents, antimicrobial agents (such as quaternary ammonium salts) and chill roll release additives (such as fatty acid amides).
As noted above, the carpet of the present invention preferably also includes a secondary backing material. Preferably, the secondary backing material is laminated directly to the extruded layer (s) while the extrudate is still molten after extrusion coating. It has been found that this technique can improve the penetration of the extrusion coating into the primary backing.
Alternatively, the secondary backing material can be laminated in a later step by reheating and/or remelting at least the outermost portion of the extruded layer or by a coextrusion coating technique using at least two dedicated extruders. Also, the secondary backing material can be laminated through some other means, such as by interposing a layer of a polymeric adhesive material between the adhesive backing material and the secondary backing material. Suitable polymeric adhesive materials include, but are not limited to, ethylene acrylic acid (EAA) copolymers, ionomers and maleic anhydride grafted polyethylene compositions.
The material for the secondary backing material can be a conventional material such as the woven polypropylene fabric sold by AMOCO under the designation Action Bac@. This material is a leno weave with polypropylene monofilaments running in one direction and polypropylene yarn running in the other. More preferably, the secondary backing material used with the present invention is a woven polypropylene fabric with monofilaments running in both directions. A suitable example of such a material is sold by Amoco under the designation Style 3878. This material has a basis weight of 2 OSY (70.7 cm3/m2). This material with monofilaments running in both directions has been found beneficial in providing enhanced dimensional stability to the carpet.
Alternatively, the secondary backing material can be a non-woven fabric.
Several types are available, including, but not limited to, spun-bond, wet-laid, melt- blown, and air entangled. As noted above, it is preferred that the secondary backing is made from a polyolefin to facilitate recycling.
Still other materials can be used for the secondary backing. For example, if an integral pad is desired, a polyurethane foam or other cushion material can be laminated to the back side of the carpet. Such backings can be used for broadloom carpet as well as for carpet tile.
The extrusion backed carpet construction and the methods described herein are particularly suited for making carpet tile. A yarn made from nylon, polypropylene, or PET, but preferably made of polypropylene, is tufted into a primary backing, which is also preferably made of polypropylene, so as to leave a carpet pile face on top of the primary backing and back stitches below the primary backing. Applied to the back of the primary backing and the back stitches is an adhesive layer. Preferably, this adhesive layer comprises a substantially random interpolymer. More preferably, the adhesive layer is made from the substantially random ethylene/vinyl aromatic interpolymers described in detail above. Most preferably, this adhesive layer is made from a substantially random ethylene/styrene interpolymer.
In a preferred embodiment of carpet tile, the carpet included from about 5 to about 200 osy (about 176.8 to about 7,074 cm3/m2) of extruded adhesive backing. More preferably, the carpet for tile includes from about 30 to about 80 osy (about 1061 to about 2,830 cm3/m2) of extruded backing, most preferably, 50 osy (1,768 cm3/m2).
Preferably, the carpet for carpet tile receives its extruded backing in two passes, that is, to apply two layers of the extruded backing. The first pass applies a layer between about 2.5 and about 100 osy (about 88.4 to about 3,537 cm3/m2) of the extruded polymer, more preferably between about 15 and about 40 osy (about 530.5 to
about 1,415 cm'/m2), and most preferably 25 osy (884 cm3/m2). The second pass adds a second layer of about 2.5 and about 100 osy (about 88.4 to about 3, 537 cm3/m), more preferably between about 15 and 40 osy (about 530.5 to about 1,415 cm3/m2), and most preferably 25 osy (884 cm3/m2).
Applying the extruded backing in two passes allows the opportunity to apply a first and second layer which have different physical and/or chemical properties. As noted above, it is sometimes preferable to apply a polymer with a higher melt index adjacent the primary backing, and a polymer with a lower melt index below that. In addition, it can also be preferably to use an extrudate with a lower filler content in the layer next to the primary backing and an extrudate with a higher filler content in the layer below that. In one preferred embodiment, the layer next to the primary backing includes a filler loading of 30 percent by weight and the layer below that includes a filler loading of 80 percent by weight. The lower filler content is believed to provide better penetration of the primary backing and back stitches in the carpet by the extrudate.
When making carpet tile, it is preferable to embed a layer of reinforcing material between the first and second layers of extruding backing. An important property of carpet tile is dimensional stability, that is, the ability of the tile to maintain its size and flatness over time. The inclusion of this layer of reinforcing material has been found to enhance the dimensional stability of carpet tile made according to this preferred embodiment. Suitable reinforcing materials include dimensionally and thermally stable fabrics such as non-woven or wet-laid fiberglass scrims, as well as woven and non- woven thermoplastic fabrics (for example polypropylene, nylon and polyester). Most preferably, the reinforcement layer is a polypropylene non-woven fabric sold by Reemay as"Typar"with a basis weight of 3.5 osy (124 cm3/m2). Alternatively, a preferred reinforcement layer is a fiberglass scrim sold by ELK Corp. as"Ultra-Mat:" with a basis weight of 1.4 osy (49.5 cm3/m2).
The carpet tile may include a secondary backing fabric below the second layer of extruded backing. Suitable materials for the secondary backing fabric include those described above. However, it is presently not preferred to include a secondary backing fabric on carpet tile.
In a carpet tile according to the present invention a length of greige good, that is yarn tufted into a primary backing, passes over two rollers with the primary backing between which is a pre-heater as described above.
An extruder is mounted so as to extrude a sheet of the polymeric backing through the die onto the back of the greige good at a point between the roller and the nip roll. The exact location at which the sheet contacts the greige good can be varied depending on the line speed and the time desired for the molten polymer to rest on the greige good before passing between the nip roll and the chill roll. At present it is preferred that the sheet contact the greige good so as to lie on the greige good for between about 0.5 and about 2 seconds, most preferably about 1 second, before passing between the nip roll and the chill roll.
In a preferred embodiment, a scrim of non-woven polypropylene is fed from roll so as to contact the chill roll at a point just prior to the nip roll. As a result, the scrim which will act as a reinforcing fabric in the finished carpet tile is laminated to the greige good through the polymer.
The pressure between the nip roll and the chill roll can be varied depending on the force desired to push the extruded sheet. Most preferably, there is 60 psi (0.41 MPa) of air pressure pushing the rolls together. Also, it may be desirable to include a vacuum slot in the nip roll. In addition, a jet of pressurized air may also be used to push the extruded sheet into the carpet backing.
The size of the chill roll and the length of time the carpet rolls against it can be varied depending on the level of cooling desired in the process. Preferably the chill roll is cooled by simply passing ambient water through it.
After passing over the chill roll, the carpet is brought over two rollers with the carpet pile toward the rollers. A second extruder extrudes a sheet of polymer through its die on to the back of the scrim. Again the point at which the extruded sheet contacts the scrim can be varied as described above.
At this point, if a secondary backing fabric is desired for the carpet tile, that fabric can be introduced from a roll so as to contact the be laminated to the carpet through the extruded sheet as it passes between the nip roll and the chill roll. Such a secondary backing fabric is not currently preferred for carpet tile construction.
The carpet passes between the nip roll and the chill rol. Again, the pressure applied between the two rolls can be varied. At present, 60 psi (0.41 MPa). of air pressure is preferably applied against the nip roll.
After passing around the chill roll, the carpet is preferably passed over an embossing roll (not shown) to print a desired pattern on the back of the carpet.
While this method is preferred for making a carpet tile with two layers of extruded backing and a reinforcing fabric in between, the same method can be used with a single extrusion die, nip roll and chill roll. In particular, the first layer of extruded backing and the reinforcing fabric can be applied in a first pass through the line after which the carpet is rolled up. The second layer of extruded backing can be applied on top of the reinforcing fabric in a second pass through the same line after which the carpet is ready to be cut into carpet tiles.
Carpet tile is typically made by producing a length of backed carpet and then cutting the carpet into the appropriate sized squares. In the United States, the most common size is 18 inches (45.7 cm) square. In the rest of the world, the most common size is 50 cm square.
Another preferred embodiment of the present invention, exclusive of an optional secondary backing material, involves the combination of the various process steps described herein together with the use of at least one substantially random interpolymer with an effective amount of an implosion agent formulated therein in the first layer of a two layer adhesive backing material.
A preferred combination of process steps at least includes; removal of processing materials by washing or scouring the greige good with an aqueous detergent solution heated to at least 67°C; drying and pre-heating the greige good by subjecting it to infra-red radiation set at about 1000°C for about 1 to about 6 seconds; extrusion coating the substantially random ethylene/styrene interpolymer adhesive backing material onto the back surface of the pre-heated, washed primary backing material by utilizing extrusion melt temperatures of greater than or equal to 615°F (324°C); subjecting the semi-molten or molten adhesive backing material to a positive air pressure device set at greater than about 60 psi (0.41 MPa) at the extrusion coating nip; and heat soaking of the carpet by subjecting it to infra-red radiation set at about 1000°C for about 1 to about 6 seconds.
Properties of the Interpolymers and Blend Compositions Used to Prepare the Carpets of the Present Invention The polymer compositions used to prepare the carpets of the present invention comprise from about 5 to 100, preferably from about 40 to 100, more preferably from about 60 to 100 wt. percent, (based on the combined weights of this component and the polymer component other than the substantially random interpolymer) of one or more interpolymers of ethylene and/or one or more a-olefins and one or more vinyl or
vinylidene aromatic monomers and/or one or more sterically hindered aliphatic or cycloaliphatic vinyl or vinylidene monomers.
These substantially random interpolymers usually contain from about 2 to about 65 preferably from about 20 to about 60, more preferably from about 30 to about 50 mole percent of at least one vinyl aromatic monomer and/or aliphatic or cycloaliphatic vinyl or vinylidene monomer and from about 35 to about 98, preferably from about 40 to about 80, more preferably from about 50 to about 70 mole percent of ethylene and/or at least one aliphatic a-olefin having from 3 to about 20 carbon atoms.
The melt index (I,) of the substantially random interpolymer used to prepare the carpets of the present invention is from about 0.01 to about 1000, preferably of from about 0.1 to about 1000, more preferably of from about 1.0 to about 50 g/10 min.
The molecular weight distribution (M » I") of the substantially random interpolymer used to prepare the carpets of the present invention is from about 1.5 to about 20, preferably of from about 1.8 to about 10, more preferably of from about 2 to about 5.
The density of the substantially random interpolymer used to prepare the carpets of the present invention is greater than about 0.930, preferably from about 0.930 to about 1.045, more preferably of from about 0.930 to about 1.040, most preferably of from about 0.930 to about 1. 030 g/cm3.
The polymer compositions used to prepare the carpets of the present invention can also comprise from 0 to about 95, preferably from 0 to about 60, more preferably from 0 to about 40 wt percent of at least one polymer other than the substantially random interpolymer (based on the combined weights of this component and the substantially random interpolymer) which can comprise a homogenous a-olefin homopolymer or interpolymer comprising polypropylene, propylene/C4-C20 a-olefin
copolymers, polyethylene, and ethylene/C3-C20 a-olefin copolymers, the interpolymers can be either heterogeneous ethylene/a-olefin interpolymers, preferably a heterogeneous ethylene/C3-C8 a-olefin interpolymer, most preferably a heterogeneous ethylene/octene-1 interpolymer or homogeneous ethylene/a-olefin interpolymers, including the substantially linear ethylene/a-olefin interpolymers, preferably a substantially linear ethylene/a-olefin interpolymer, most preferably a substantially linear ethylene/C3-Cs a-olefin interpolymer; or a heterogeneous ethylene/a-olefin interpolymer; or a thermoplastic olefin, preferably an ethylene/propylene rubber (EPM) or ethylene/propylene diene monomer terpolymer (EPDM) or isotactic polypropylene, most preferably isotactic polypropylene; or a styreneic block copolymer, preferably styrene-butadiene (SB), styrene-isoprene (SI), styrene-butadiene-styrene (SBS), styrene- isoprene-styrene (SIS) or styrene-ethylene/butene-styrene (SEBS) block copolymer, most preferably a styrene-butadiene-styrene (SBS) copolymer; or styrenic homopolymers or copolymers, preferably polystyrene, high impact polystyrene, polyvinyl chloride, copolymers of styrene and at least one of acrylonitrile, methacrylonitrile, maleic anhydride, or a-methyl styrene, most preferably polystyrene, or elastomers, preferably polyisoprene, polybutadiene, natural rubbers, ethylene/propylene rubbers, ethylene/propylene diene (EPDM) rubbers, styrene/butadiene rubbers, thermoplastic polyurethanes, most preferably thermoplastic polyurethanes; or engineering thermosplastics, preferably poly (methylmethacrylate) (PMMA), cellulosics, nylons, poly (esters), poly (acetals); poly (amides), the poly (arylate), aromatic polyesters, poly (carbonate), poly (butylene) and polybutylene and polyethylene terephthalates, most preferably poly (methylmethacrylate) (PMMA), and-poly (esters).
Carpet, especially broadloom carpet, with a layer of ethylene/styrene interpolymers as the contacting surface adheres well to SBR latex mastics routinely used for commercial carpet installations. This good adhesion to incumbent mastics results in carpet with good glue down installability. Carpet with a layer of ITP, or
similar material, as the contacting surface requires an adhesion promoter or tie layer to install with SBR latex mastics.
Carpet with a layer containing ethylene/styrene interpolymers, either as sole layer or as a layer in a multilayer backing system, results in carpet with good flexibility and conformability. Good flexibility is desired for ease of handling and installation.
Carpet with other polyolefin backing systems generally exhibit significant elastic memory and do not conform as well as carpet with an ethylene/styrene interpolymers containing layer. Good conformability, or the ability to follow contours or imperfections in subflooring, is especially found with layers containing ethylene/styrene interpolymers with a Tg range of-20 to about 45, more preferably from-10 to about 35, most preferably from 0 to about 30°C.
Carpet backing formulations based on other polyolefins and f-PVC that contain filler, especially for carpet tile, require extensive tackifiers, processing aids, filler coupling agent, and/or tackifiers in order to permit filler incorporation, processing, or to improve layflatness for installability. Filled ethylene/styrene interpolymer formulations do not require coupling agents to achieve good filler holding and do not require additives to improve layflatness, especially with formulations containing ethylene/styrene interpolymers with a Tg range of 0 to 35 degrees C.
Carpet backing formulations containing ethylene/styrene interpolymers exhibit improved sound deadening/dampening and static dissipation compared to other referenced systems.
The following examples are illustrative of the invention, but are not to be construed as to limiting the scope thereof in any manner.
EXAMPLES Test Methods
a) Melt Flow and Densitv Measurements The molecular weight of the polymer compositions for use in the present invention is conveniently indicated using a melt index measurement according to ASTM D-1238, Condition 190°C/2.16 kg (formally known as"Condition (E)"and also known as 12) was determined. Melt index is inversely proportional to the molecular weight of the polymer. Thus, the higher the molecular weight, the lower the melt index, although the relationship is not linear.
Also useful for indicating the molecular weight of the substantially random interpolymers used in the present invention is the Gottfert melt index (G, cm3/10 min) which is obtained in a similar fashion as for melt index (I,) using the ASTM D1238 procedure for automated plastometers, with the melt density set to 0.7632, the melt density of polyethylene at 190°C.
The relationship of melt density to styrene content for ethylene-styrene interpolymers was measured, as a function of total styrene content, at 190°C for a range of 29.8 percent to 81.8 percent by weight styrene. Atactic polystyrene levels in these samples was typically 10 percent or less. The influence of the atactic polystyrene was assumed to be minimal because of the low levels. Also, the melt density of atactic polystyrene and the melt densities of the samples with high total styrene are very similar. The method used to determine the melt density employed a Gottfert melt index machine with a melt density parameter set to 0.7632, and the collection of melt strands as a function of time while the 12 weight was in force. The weight and time for each melt strand was recorded and normalized to yield the mass in grams per 10 minutes.
The instrument's calculated 12 melt index value was also recorded. The equation used to calculate the actual melt density is 6 = 60. 7632 x I2/I2 Gottfert where 6 07632= 0.7632 and I2 Gottfert = displayed melt index.
A linear least squares fit of calculated melt density versus total styrene content leads to an equation with a correlation coefficient of 0.91 for the following equation: 6 = 0.00299 x S + 0.723 where S = weight percentage of styrene in the polymer. The relationship of total styrene to melt density can be used to determine an actual melt index value, using these equations if the styrene content is known.
So for a polymer that is 73 percent total styrene content with a measured melt flow (the"Gottfert number"), the calculation becomes: 6 = 0.00299*73 + 0.723 = 0.9412 where 0.9412/0.7632 = I,/G# (measured) = 1.23 The density of the substantially random interpolymers used in the present invention was determined in accordance with ASTM D-792. b) Styrene Analyses Interpolymer styrene content and atactic polystyrene concentration were determined using proton nuclear magnetic resonance ('H N. M. R). All proton NMR samples were prepared in 2-tetrachloroethane-d2 (TCE-d2). The resulting solutions were 1.6-3.2 percent polymer by weight. Melt index (I2) was used as a guide for determining sample concentration. Thus when the I2 was greater than 2 g/10 min, 40 mg of interpolymer was used; with an I2 between 1.5 and 2 g/10 min, 30 mg of interpolymer was used; and when the I2 was less than 1.5 g/10 min, 20 mg of interpolymer was used. The interpolymers were weighed directly into 5 mm sample tubes. A 0.75 mL aliquot of TCE-d2 was added by syringe and the tube was capped with a tight-fitting polyethylene cap. The samples were heated in a water bath at 85°C to soften the interpolymer. To provide mixing, the capped samples were occasionally brought to reflux using a heat gun.
Proton NMR spectra were accumulated on a Varian VXR 300 with the sample probe at 80°C, and referenced to the residual protons of TCE-d, at 5.99 ppm. The delay
times were varied between 1 second, and data was collected in triplicate on each sample. The following instrumental conditions were used for analysis of the interpolymer samples: Varian VXR-300, standard'H: Sweep Width, 5000 Hz Acquisition Time, 3.002 sec Pulse Width, 8 sec Frequency, 300 MHz Delay, 1 sec Transients, 16 The total analysis time per sample was about 10 minutes.
Initially, a'H NMR spectrum for a sample of the polystyrene, Styron'680 (available from and a registered trademark of The Dow Chemical Company, Midland, MI) was acquired with a delay time of one second. The protons were"labeled" : b, branch; a, alpha; o, ortho; m, meta; p, para, as shown in Figure 1.
Figure 1.
Integrals were measured around the protons labeled in Figure 1; the'A' designates aPS. Integral A,., (aromatic, around 7.1 ppm) is believed to be the three ortho/para protons; and integral A6 6 (aromatic, around 6.6 ppm) the two meta protons.
The two aliphatic protons labeled a resonate at 1.5 ppm; and the single proton labeled b is at 1.9 ppm. The aliphatic region was integrated from about 0.8 to 2.5 ppm and is
referred to as Aal. The theoretical ratio for A7.,: A6 6 Aal is 3: 2: 3, or 1.5: 1: 1.5, and correlated very well with the observed ratios for the Styron'680 sample for several delay times of 1 second. The ratio calculations used to check the integration and verify peak assignments were performed by dividing the appropriate integral by the integral A6. Ratio A, is Ay,/A. 1/A6. 6- Region A6. 6 was assigned the value of 1. Ratio Al is integral Aal/A6 6. All spectra collected have the expected 1.5: 1: 1.5 integration ratio of (o+p) : m : (a+b). The ratio of aromatic to aliphatic protons is 5 to 3. An aliphatic ratio of 2 to 1 is predicted based on the protons labeled a and b respectively in Figure 1. This ratio was also observed when the two aliphatic peaks were integrated separately.
For the ethylene/styrene interpolymers, the'H NMR spectra using a delay time of one second, had integrals C,, C6. 6, and Cal defined, such that the integration of the peak at 7.1 ppm included all the aromatic protons of the copolymer as well as the o & p protons of aPS. Likewise, integration of the aliphatic region Cal in the spectrum of the interpolymers included aliphatic protons from both the aPS and the interpolymer with no clear baseline resolved signal from either polymer. The integral of the peak at 6.6 ppm C6 6 is resolved from the other aromatic signals and it is believed to be due solely to the aPS homopolymer (probably the meta protons). (The peak assignment for atactic polystyrene at 6.6 ppm (integral A6. 6) was made based upon comparison to the authentic sample Styron'680 (available from and a registered trademark of The Dow Chemical Company, Midland, MI)). This is a reasonable assumption since, at very low levels of atactic polystyrene, only a very weak signal is observed here. Therefore, the phenyl protons of the copolymer must not contribute to this signal. With this assumption, integral A6. 6 becomes the basis for quantitatively determining the aPS content.
The following equations were then used to determine the degree of styrene incorporation in the ethylene/styrene interpolymer samples: (CPhenyl) =C,, +A,,- (1. 5xA)
(C Aliphatic) = Cal- (1 5 x A6. 6) s, = (C Phenyl)/5 e, = (C Aliphatic- (3 x su))/4 and the following equations were used to calculate the mol percent ethylene and styrene in the interpolymers.
E*28 (E*28) + (Sc*104) and and Wt% S=-----------(100)<BR> <BR> <BR> <BR> (E*28) + (SC*104) where: s and e are styrene and ethylene proton fractions in the interpolymer, respectively, and S. and E are mole fractions of styrene monomer and ethylene monomer in the interpolymer, respectively.
The weight percent of aPS in the interpolymers was then determined by the following equation: The total styrene content was also determined by quantitative Fourier Transform Infrared spectroscopy (FTIR).
Preparation of Ethvlene/Stvrene Interpolvmers Used in Examples and Comparative Experiments of Present Invention 1) Preparation of ESI #'s 1-2
ESI #'s 1-2 are substantially random ethylene/styrene interpolymers prepared using the following catalyst and polymerization procedures.
Preparation of Catalyst A (dimethvlEN-(1. I-dimethvlethyl)-1 * 1-dimethvl-1-(1.2.3,4,5- n)-1,5.*67-tetrahvdro-3-phenvl-s-indacen-1-vl silanaminato (2-)-Nl-titanium) 1) Preparation of 3,5,6,7-Tetrahydro-s-Hydrindacen-1 (2H)-one Indan (94.00 g, 0.7954 moles) and 3-chloropropionyl chloride (100.99 g, 0.7954 moles) were stirred in CH, Cl2 (300 mL) at 0°C as AlCI3 (130. 00 g, 0.9750 moles) was added slowly under a nitrogen flow. The mixture was then allowed to stir at room temperature for 2 hours. The volatiles were then removed. The mixture was then cooled to 0°C and concentrated H2SO4 (500 mL) slowly added. The forming solid had to be frequently broken up with a spatula as stirring was lost early in this step. The mixture was then left under nitrogen overnight at room temperature. The mixture was then heated until the temperature readings reached 90°C. These conditions were maintained for a 2 hour period of time during which a spatula was periodically used to stir the mixture. After the reaction period crushed ice was placed in the mixture and moved around. The mixture was then transferred to a beaker and washed intermittently with H, O and diethylether and then the fractions filtered and combined. The mixture was washed with HO (2 x 200 mL). The organic layer was then separated and the volatiles removed. The desired product was then isolated via recrystallization from hexane at 0°C as pale yellow crystals (22.36 g, 16.3 percent yield).
OH NMR (CDCl3): d2.04-2.19 (m, 2 H), 2.65 (t, 3JHH=5.7 Hz, 2 H), 2.84-3.0 (m, 4 H), 3.03 (t, 3JHH=5. 5 Hz, 2 H), 7.26 (s, 1 H), 7.53 (s, 1 H).
CNMR (CDCl3): 90,122.16,135.88,144.06, 152.89,154.36,206.50.
GC-MS: Calculated for CHO 172.09, found 172.05.
2) Preparation of 1,2,3,5-Tetrahydro-7-phenyl-s-indacen.
3,5,6,7-Tetrahydro-s-Hydrindacen-1 (2H)-one (12.00 g, 0.06967 moles) was stirred in diethylether (200 mL) at 0°C as PhMgBr (0.105 moles, 35.00 mL of 3.0 M solution in diethylether) was added slowly. This mixture was then allowed to stir overnight at room temperature. After the reaction period the mixture was quenched by pouring over ice. The mixture was then acidified (pH=1) with HCl and stirred vigorously for 2 hours. The organic layer was then separated and washed with H, O (2 x 100 mL) and then dried over MgSO4. Filtration followed by the removal of the volatiles resulted in the isolation of the desired product as a dark oil (14.68 g, 90.3 percent yield).
OH NMR (CDCI3): d2.0-2.2 (m, 2 H), 2.8-3.1 (m, 4 H), 6.54 (s, 1H), 7.2-7.6 (m, 7 H).
GC-MS: Calculated for C, 8H, 6 232.13, found 232.05.
3) Preparation of 1,2,3,5-Tetrahydro-7-phenyl-s-indacene, dilithium salt.
1,2,3,5-Tetrahydro-7-phenyl-s-indacen (14.68 g, 0.06291 moles) was stirred in hexane (150 mL) as nBuLi (0.080 moles, 40.00 mL of 2.0 M solution in cyclohexane) was slowly added. This mixture was then allowed to stir overnight. After the reaction period the solid was collected via suction filtration as a yellow solid which was washed with hexane, dried under vacuum, and used without further purification or analysis (12.2075 g, 81.1 percent yield).
4) Preparation of Chlorodimethyl (1,5,6,7-tetrahydro-3-phenyl-s-indacen-1-yl) silane.
1,2,3,5-Tetrahydro-7-phenyl-s-indacene, dilithium salt (12.2075 g, 0.05102 moles) in THF (50 mL) was added dropwise to a solution of Me2SiCl2 (19.5010 g, 0.1511 moles) in THF (100 mL) at 0°C. This mixture was then allowed to stir at room temperature overnight. After the reaction period the volatiles were removed and the residue extracted and filtered using hexane. The removal of the hexane resulted in the isolation of the desired product as a yellow oil (15.1492 g, 91.1 percent yield).
H NMR (CDC13): dO. 33 (s, 3 H), 0.38 (s, 3 H), 2.20 (p, 3JHH=7. 5 Hz, 2 H), 2.9-3.1 (m, 4 H), 3. 84 (s, 1 H), 6.69 (d, JHH=2 8 Hz, 1 H), 7 3-7 6 (m, 7 H), 7 68 (d, JHH=7-4 Hz, 2 H).
C NMR (CDCI3) : dO. 24, 0. 38, 26. 28, 33. 05, 33. 18, 46. 13, 116. 42, 119. 71, 127. 51, GC-MS: Calculated for CHCISi 324. 11, found 324.05.
5) Preparation of N- (1, 1-Dimethylethyl)-1, 1-dimethyl-1- (1,5,6,7-tetrahydro-3-phenyl- s-indacen-1-yl)silanamine.
Chlorodimethyl (1,5,6,7-tetrahydro-3-phenyl-s-indacen-1-yl) silane (10.8277 g, 0.03322 moles) was stirred in hexane (150 mL) as NEt3 (3.5123 g, 0.03471 moles) and t-butylamine (2.6074 g, 0.03565 moles) were added. This mixture was allowed to stir for 24 hours. After the reaction period the mixture was filtered and the volatiles removed resulting in the isolation of the desired product as a thick red-yellow oil (10.6551 g, 88.7 percent yield).
OH NMR (CDCI3): dO. 02 (s, 3 H), 0.04 (s, 3 H), 1.27 (s, 9 H), 2.16 (p, 3JHH=7.2 Hz, 2 H), 2.9-3.0 (m, 4 H), 3.68 (s, 1 H), 6.69 (s, 1 H), 7.3-7.5 (m, 4 H), 7.63 (d, 3JHH=7.4 Hz, 2 H).
C NMR (CDCI3): d-0.32,-0.09,26.28,33.39,34.11,46.46,47.54,49.81,115.80, 119.30,126.92,127.89,128.46,132.99,137.30,140.20,140.81,141. 64,142.08, 144.83.
6) Preparation of N- (1,1-Dimethylethyl)-1,1-dimethyl-1- (1,5,6,7-tetrahydro-3-phenyl- s-indacen-1-yl) silanamine, dilithium salt.
N- (1, 1-Dimethylethyl)-1, 1-dimethyl-1- (1,5,6,7-tetrahydro-3-phenyl-s-indacen- 1-yl) silanamine (10.6551 g, 0.02947 moles) was stirred in hexane (100 mL) as nBuLi (0.070 moles, 35.00 mL of 2.0 M solution in cyclohexane) was added slowly. This mixture was then allowed to stir overnight during which time no salts crashed out of the dark red solution. After the reaction period the volatiles were removed and the residue
quickly washed with hexane (2 x 50 mL). The dark red residue was then pumped dry and used without further purification or analysis (9.6517 g, 87.7 percent yield).
7) Preparation of Dichloro N- (1, 1-dimethylethyl)-1, 1-dimethyl-1- (1,2,3,4,5-)- 1,5,6,7-tetrahydro-3-phenyl-s-indacen-1-yl silanaminato (2-)-N] titanium N-(1, 1-Dimethylethyl)-1, 1-dimethyl-1-(1,(1, 1-Dimethylethyl)-1, 1-dimethyl-1-(1, 5,6,7-tetrahydro-3-phenyl-s-indacen- 1-yl) silanamine, dilithium salt (4.5355 g, 0.01214 moles) in THF (50 mL) was added dropwise to a slurry of TiCI3 (THF) 3 (4.5005 g, 0.01214 moles) in THF (100 mL). This mixture was allowed to stir for 2 hours. PbCI2 (1.7136 g, 0.006162 moles) was then added and the mixture allowed to stir for an additional hour. After the reaction period the volatiles were removed and the residue extracted and filtered using toluene.
Removal of the toluene resulted in the isolation of a dark residue. This residue was then slurried in hexane and cooled to 0°C. The desired product was then isolated via filtration as a red-brown crystalline solid (2.5280 g, 43.5 percent yield).
OH NMR (CDCI3): dO. 71 (s, 3 H), 0.97 (s, 3 H), 1.37 (s, 9 H), 2.0-2.2 (m, 2 H), 2.9-3.2 (m, 4 H), 6.62 (s, 1 H), 7.35-7.45 (m, 1 H), 7.50 (t,'JHH=7.8 Hz, 2 H), 7.57 (s, 1 H), 7.70 (d,'JHH=7.1 Hz, 2 H), 7.78 (s, 1 H).
OH NMR (C, D6): dO. 44 (s, 3 H), 0.68 (s, 3 H), 1. 35 (s, 9 H), 1.6-1.9 (m, 2 H), 2.5-3.9 (m, 4 H), 6.65 (s, 1 H), 7.1-7.2 (m, 1 H), 7.24 (t, 3JHH=7.1 Hz, 2 H), 7.61 (s, 1 H), 7.69 (s, 1 H), 7.77-7.8 (m, 2 H).
C NMR (CDCI3): dl. 29,3.89,26.47,32.62,32.84,32.92,63.16,98.25,118.70, 121.75,125.62,128.46,128.55,128.79,129.01,134.11,134.53,136. 04,146.15, 148.93.
C NMR (C6D6): dO. 90,3.57,26.46,32.56,32.78,62.88,98.14,119.19,121.97, 125.84,127.15,128.83,129.03,129.55,134.57,135.04,136.41,136. 51,147.24, 148.96.
8) Preparation of Dimethyl N-(1, 1-dimethylethyl)-1, I-dimethyl-1-(1, 2, 3,4,5-tel)- 1,5,6,7-tetrahydro-3-phenyl-s-indacen-1-yl silanaminato (2-)-N] titanium Dichloro N-(1, 1-dimethylethyl)-1, 1-dimethyl-1-(1, 2, 3,4,5-1j)-1,5,6,7- tetrahydro-3-phenyl-s-indacen-1-yl silanaminato (2-)-N] titanium (0.4970 g, 0.001039 moles) was stirred in diethylether (50 mL) as MeMgBr (0.0021 moles, 0.70 mL of 3.0 M solution in diethylether) was added slowly. This mixture was then stirred for 1 hour.
After the reaction period the volatiles were removed and the residue extracted and filtered using hexane. Removal of the hexane resulted in the isolation of the desired product as a golden yellow solid (0.4546 g, 66.7 percent yield).
OH NMR (C6D6): dO. 071 (s, 3 H), 0.49 (s, 3 H), 0.70 (s, 3 H), 0.73 (s, 3 H), 1.49 (s, 9 H), 1.7-1.8 (m, 2 H), 2.5-2.8 (m, 4 H), 6.41 (s, 1 H), 7.29 (t, 3JHH=7. 4 Hz, 2 H), 7.48 (s, 1 H), 7.72 (d, JHH=7.4 Hz, 2 H), 7.92 (s, 1 H).
C NMR (C6D6): 33.00,34.73,58.68,58.82,118.62,121.98, 144.85.
Preparation of Catalyst B : (lH-cyclopenta l phenanthrene-2-yl ! dimethvl (t-butVlamido)- silanetitanium 1,4-diphenvlbutadiene) 1) Preparation of lithium 1 H-cyclopenta 1 phenanthrene-2-yl To a 250 ml round bottom flask containing 1.42 g (0.00657 mole) of 1H- cyclopenta l phenanthrene and 120 ml of benzene was added dropwise, 4.2 ml of a 1.60 M solution of n-BuLi in mixed hexanes. The solution was allowed to stir overnight.
The lithium salt was isolated by filtration, washing twice with 25 ml benzene and drying under vacuum. Isolated yield was 1.426 g (97.7 percent). 1H NMR analysis indicated the predominant isomer was substituted at the 2 position.
2) Preparation of (1 H-cyclopenta l phenanthrene-2-yl) dimethylchlorosilane To a 500 ml round bottom flask containing 4.16 g (0.0322 mole) of dimethyldichlorosilane (Me2SiCl2) and 250 ml of tetrahydrofuran (THF) was added dropwise a solution of 1.45 g (0.0064 mole) of lithium lH-cyclopenta l phenanthrene-
2-yl in THF. The solution was stirred for approximately 16 hours, after which the solvent was removed under reduced pressure, leaving an oily solid which was extracted with toluene, filtered through diatomaceous earth filter aid (CeliteTiM), washed twice with toluene and dried under reduced pressure. Isolated yield was 1.98 g (99.5 percent).
3. Preparation of (1 H-cyclopenta l phenanthrene-2-yl) dimethyl (t-butylamino) silane To a 500 ml round bottom flask containing 1.98 g (0.0064 mole) of (1 H- cyclopenta l phenanthrene-2-yl) dimethylchlorosilane and 250 ml of hexane was added 2.00 ml (0.0160 mole) of t-butylamine. The reaction mixture was allowed to stir for several days, then filtered using diatomaceous earth filter aid (CeliteT), washed twice with hexane. The product was isolated by removing residual solvent under reduced pressure. The isolated yield was 1.98 g (88.9 percent).
4. Preparation of dilithio (1 H-cyclopenta l phenanthrene-2-yl) dimethyl (t- butylamido) silane To a 250 ml round bottom flask containing 1.03 g (0.0030 mole) of (1H- cyclopenta l phenanthrene-2-yl) dimethyl (t-butylamino) silane) and 120 ml of benzene was added dropwise 3.90 ml of a solution of 1.6 M n-BuLi in mixed hexanes. The reaction mixture was stirred for approximately 16 hours. The product was isolated by filtration, washed twice with benzene and dried under reduced pressure. Isolated yield was 1.08 g (100 percent).
5. Preparation of (1 H-cyclopenta l phenanthrene-2-yl) dimethyl (t- butylamido) silanetitanium dichloride To a 250 ml round bottom flask containing 1.17 g (0.0030 mole) of TiC13. 3THF and about 120 ml of THF was added at a fast drip rate about 50 ml of a THF solution of 1.08 g of dilithio (lH-cyclopenta l phenanthrene-2-yl) dimethyl (t- butylamido) silane. The mixture was stirred at about 20 °C for 1.5 h at which time 0.55 gm (0.002 mole) of solid PbC12 was added. After stirring for an additional 1.5 h the
THF was removed under vacuum and the reside was extracted with toluene, filtered and dried under reduced pressure to give an orange solid. Yield was 1. 31 g (93.5 percent).
6. Preparation of (1 H-cyclopenta l phenanthrene-2-yl) dimethyl (t- butylamido) silanetitanium 1,4-diphenylbutadiene To a slurry of (1 H-cyclopenta l phenanthrene-2-yl) dimethyl (t- butylamido) silanetitanium dichloride (3.48 g, 0.0075 mole) and 1.551 gm (0.0075 mole) of 1,4-diphenyllbutadiene in about 80 ml of toluene at 70°C was add 9.9 ml of a 1.6 M solution of n-BuLi (0.0150 mole). The solution immediately darkened. The temperature was increased to bring the mixture to reflux and the mixture was maintained at that temperature for 2 hrs. The mixture was cooled to about-20 °C and the volatiles were removed under reduced pressure. The residue was slurried in 60 ml of mixed hexanes at about 20°C for approximately 16 hours. The mixture was cooled to about-25°C for about 1 h. The solids were collected on a glass frit by vacuum filtration and dried under reduced pressure. The dried solid was placed in a glass fiber thimble and solid extracted continuously with hexanes using a soxhlet extractor. After 6 h a crystalline solid was observed in the boiling pot. The mixture was cooled to about -20°C, isolated by filtration from the cold mixture and dried under reduced pressure to give 1.62 g of a dark crystalline solid. The filtrate was discarded. The solids in the extractor were stirred and the extraction continued with an additional quantity of mixed hexanes to give an additional 0.46 gm of the desired product as a dark crystalline solid.
Polymerization ESI 1 was prepared in a continuously operating loop reactor (36.8 gal, 0.14 m3).
An Ingersoll-Dresser twin screw pump provided the mixing. The reactor ran liquid full at 475 psig (3,275 kPa) with a residence time of approximately 25 minutes. Raw materials and catalyst/cocatalyst flows were fed into the suction of the twin screw pump through injectors and Kenics static mixers. The twin screw pump discharged into a 2" diameter line which supplied two Chemineer-Kenics 10-68 Type BEM Multi-Tube heat exchangers in series. The tubes of these exchangers contained twisted tapes to increase
heat transfer. Upon exiting the last exchanger, loop flow returned through the injectors and static mixers to the suction of the pump. Heat transfer oil was circulated through the exchangers'jacket to control the loop temperature probe located just prior to the first exchanger. The exit stream of the loop reactor was taken off between the two exchangers. The flow and solution density of the exit stream was measured by a MicroMotion.
Solvent feed to the reactor was supplied by two different sources. A fresh stream of toluene from an 8480-S-E Pulsafeeder diaphragm pump with rates measured by a MicroMotion flowmeter was used to provide flush flow for the reactor seals (20 Ib/hr (9.1 kg/hr). Recycle solvent was mixed with uninhibited styrene monomer on the suction side of five 8480-5-E Pulsafeeder diaphragm pumps in parallel. These five Pulsafeeder pumps supplied solvent and styrene to the reactor at 650 psig (4,583 kPa).
Fresh styrene flow was measured by a MicroMotion flowmeter, and total recycle solvent/styrene flow was measured by a separate MicroMotion flowmeter. Ethylene was supplied to the reactor at 687 psig (4,838 kPa). The ethylene stream was measured by a Micro-Motion mass flowmeter. A Brooks flowmeter/controller was used to deliver hydrogen into the ethylene stream at the outlet of the ethylene control valve.
The ethylene/hydrogen mixture combined with the solvent/styrene stream at ambient temperature. The temperature of the entire feed stream as it entered the reactor loop was lowered to 2°C by an exchanger with-10°C glycol on the jacket. Preparation of the three catalyst components took place in three separate tanks: fresh solvent and concentrated catalyst/cocatalyst premix were added and mixed into their respective run tanks and fed into the reactor via variable speed 680-S-AEN7 Pulsafeeder diaphragm pumps. As previously explained, the three component catalyst system entered the reactor loop through an injector and static mixer into the suction side of the twin screw pump. The raw material feed stream was also fed into the reactor loop through an injector and static mixer downstream of the catalyst injection point but upstream of the twin screw pump suction.
Polymerization was stopped with the addition of catalyst kill (water mixed with solvent) into the reactor product line after the Micro Motion flowmeter measuring the solution density. A static mixer in the line provided dispersion of the catalyst kill and additives in the reactor effluent stream. This stream next entered post reactor heaters that provided additional energy for the solvent removal flash. This flash occurred as the effluent exited the post reactor heater and the pressure was dropped from 475 psig (3,275 kPa) down to 450 mmHg (60 kPa) of absolute pressure at the reactor pressure control valve.
This flashed polymer entered the first of two hot oil jacketed devolatilizers. The volatiles flashing from the first devolatizer were condensed with a glycol jacketed exchanger, passed through the suction of a vacuum pump, and were discharged to the solvent and styrene/ethylene separation vessel. Solvent and styrene were removed from the bottom of this vessel as recycle solvent while ethylene exhausted from the top. The ethylene stream was measured with a MicroMotion mass flowmeter. The measurement of vented ethylene plus a calculation of the dissolved gases in the solvent/styrene stream were used to calculate the ethylene conversion. The polymer and remaining solvent separated in the devolatilizer was pumped with a gear pump to a second devolatizer. The pressure in the second devolatizer was operated at 5 mmHg (0.7 kPa) absolute pressure to flash the remaining solvent. This solvent was condensed in a glycol heat exchanger, pumped through another vacuum pump, and exported to a waste tank for disposal. The dry polymer (< 1000 ppm total volatiles) was pumped with a gear pump to an underwater pelletizer with 6-hole die, pelletized, spin-dried, and collected in 1000 lb boxes.
ESI 2 was prepared in a 6 gallon (22.7 L), oil jacketed, Autoclave continuously stirred tank reactor (CSTR). A magnetically coupled agitator with Lightning A-320 impellers provided the mixing. The reactor ran liquid full at 475 psig (3,275 kPa).
Process flow was in at the bottom and out of the top. A heat transfer oil was circulated through the jacket of the reactor to remove some of the heat of reaction. At the exit of
the reactor was a micromotion flow meter that measured flow and solution density. All lines on the exit of the reactor were traced with 50 psi (344.7 kPa) steam and insulated.
Toluene solvent was supplied to the reactor at 30 psig (207 kPa). The feed to the reactor was measured by a Micro-Motion mass flow meter. A variable speed diaphragm pump controlled the feed rate. At the discharge of the solvent pump, a side stream was taken to provide flush flows for the catalyst injection line (1 lb/hr (0.45 kg/hr)) and the reactor agitator (0.75 lb/hr (0.34 kg/hr)). These flows were measured by differential pressure flow meters and controlled by manual adjustment of micro-flow needle valves. Uninhibited styrene monomer was supplied to the reactor at 30 psig (207 kpa). The feed to the reactor was measured by a Micro-Motion mass flow meter.
A variable speed diaphragm pump controlled the feed rate. The styrene stream was mixed with the remaining solvent stream.
Ethylene was supplied to the reactor at 600 psig (4,137 kPa). The ethylene stream was measured by a Micro-Motion mass flow meter just prior to the Research valve controlling flow. A Brooks flow meter/controller was used to deliver hydrogen into the ethylene stream at the outlet of the ethylene control valve. The ethylene/hydrogen mixture combines with the solvent/styrene stream at ambient temperature. The temperature of the solvent/monomer as it enters the reactor was dropped to-5°C by an exchanger with-5°C glycol on the jacket. This stream entered the bottom of the reactor.
The three component catalyst system and its solvent flush also entered the reactor at the bottom but through a different port than the monomer stream. Preparation of the catalyst components took place in an inert atmosphere glove box. The diluted components were put in nitrogen padded cylinders and charged to the catalyst run tanks in the process area. From these run tanks the catalyst was pressured up with piston pumps and the flow was measured with Micro-Motion mass flow meters. These
streams combine with each other and the catalyst flush solvent just prior to entry through a single injection line into the reactor.
Polymerization was stopped with the addition of catalyst kill (water mixed with solvent) into the reactor product line after the micromotion flow meter measuring the solution density. Other polymer additives can be added with the catalyst kill. A static mixer in the line provided dispersion of the catalyst kill and additives in the reactor effluent stream. This stream next entered post reactor heaters that provide additional energy for the solvent removal flash. This flash occurred as the effluent exited the post reactor heater and the pressure was dropped from 475 psig (3,275 kPa) down to-250 mm of pressure absolute at the reactor pressure control valve. This flashed polymer entered a hot oil jacketed devolatilizer. Approximately 85 percent of the volatiles were removed from the polymer in the devolatilizer. The volatiles exited the top of the devolatilizer. The stream was condensed with a glycol jacketed exchanger and entered the suction of a vacuum pump and was discharged to a glycol jacket solvent and styrene/ethylene separation vessel. Solvent and styrene were removed from the bottom of the vessel and ethylene from the top. The ethylene stream was measured with a Micro-Motion mass flow meter and analyzed for composition. The measurement of vented ethylene plus a calculation of the dissolved gasses in the solvent/styrene stream were used to calculate the ethylene conversion. The polymer separated in the devolatilizer was pumped out with a gear pump to a ZSK-30 devolatilizing vacuum extruder. The dry polymer exits the extruder as a single strand. This strand was cooled as it was pulled through a water bath. The excess water was blown from the strand with air and the strand was chopped into pellets with a strand chopper.
The various catalysts, co-catalysts and process conditions used to prepare the various individual ethylene styrene interpolymers (ESI #'s 1-2) are summarized in Table 1 and their properties are summarized in Table 2.
Table 1. Preparation Conditions for ESI #'s 1-2 ESI Reactor Solvent Ethylene Hydrogen Styrene Ethylene B/Ti MMAO'/Ti Catalyst Co- # Temp Flow Flow Flow Flow Conversion Ratio Ratio Catalyst °C Ib/hr Ib/hr sccm lb/hr percent (kg/hr) (kg/hr) (kg/hr) ESI 60. 0 370 20.0 (9.1) 0. 12 98 (44.4) 88.0 3. 50 2. 5 Bb C' 1 (168) ESI 73. 3 34. 0 1. 88 (0.85) 7.39 14.4 96.5 3.50 9.0 Aª Cc 2 (15.4) (6.5) *N/A = not available
a Catalyst A is dimethyl N- (I, I-dimethylethyl)-I, I-dimethyl-l- (1,2,3,4,5-Tl)-l, 5,6,7-tetrahydro-3-phenyl-s-indacen-I- yl silanaminato (2-)-N-titanium. b Catalyst B is ; (1 H-cyclopenta[1]phenanthrene-2-yl)dimethyl(t-butylamido)-sila netitanium 1,4-diphenylbutadiene) c Cocatalyst C is tris (pentafluorophenyl) borane, (CAS# 001109-15-5),. d a modified methylaluminoxane commercially available from Akzo Nobel as MMAO-3A (CAS# 146905-79-5) Table 2. Properties of ESI #'s 1-2. ESI # Total Wt wt. percent mol. percent Melt Index I2 percent Copolymer Styrene Copolymer (g/10 min) Styrene Styrene ESI-1 77. 3 69. 3 37. 8 6. 25 ESI-2 70. 5 70. 0 3 8. 6 1. 3
For the examples, carpet structures comprising ethylene/styrene interpolymers- based backing material were prepared by a number of methods, and were compared to carpet structures made with EO-based backing material. Key carpet performance properties were measured, and a glue down installation was conducted.
Table 3 lists the other evaluated backing component materials.
TABLE 3: Other Materials used in Examples Sample ID Description Melt Index Density I=, g/10 min g/cm3 P I ethylene octene copolymer* 30.0 0. 885 P 2 ethylene octene copolymer* 200.0 0.890 CaC03 Georgia Marble #9 Ground limestone, 325 mesh na na * prepared as described in U. S. Patent No. 5.272,236 For Examples 1-18, samples of uncoated tufted carpet, known to the industry as greige goods, were extrusion coated with various formulations under a range of processing conditions. Die configuration was monolayer, although, single die co- extrusion and dual lip die co-extrusion could be used. Auxiliary equipment included a carpet pre-heater. Greige goods samples were extrusion coated with ethylene/styrene interpolymers, EO, and dry-blended EO/ethylene/styrene interpolymers blends.
The coating equipment used for these examples consists of a two-extruder Black Clawson coextrusion line with a 3'/2 inch (8.9 cm) diameter primary extruder with a 30: 1 L/D and 2*4 inch (6.4 cm) secondary extruder with a 24: 1 L/D. For these examples, only the large extruder was operated at variable rates to control coating thickness. A 76 cm slot die is attached and was deckled to 69 cm with a 20 mil die gap and a 6 inch (15.2 cm) air/draw gap. The nip roll pressure was set at 30 psi (207 kPa), the chill roll temperature ran at 60-80 °F, (15-27°C) and the line speed was set at 75 feet/min (0.38 m/s). The carpet was pre-heated to 180 °F (82°C) in a convection oven and the extrusion melt temperature was 500-550 °F (260-288°C).
The primary performance criteria listed in the examples included: tuft bind, abrasion resistance (indicated by velcro rating and fuzz number), lamination strength, and flexibility. Tuft bind testing was conducted using ASTM-D-1335-67. Abrasion resistance and velcro testing were based on a qualitative test. In the test, a 2 inch (5.1 cm) diameter, 2 lb (0.9 kg) roller coated with the loop side of standard velcro is passed 10 times over the face side of coated carpet samples. The fuzz on the abraded carpet
was then compared to a set of carpet standards and rated on a 1-10 scale (10 rating showing zero fuzz).
To provide quantitative abrasion results, a Fiber Lock Test was used. In this test, the abrasion resistance value is taken as the"Fiber Lock Fuzz Number."The test involves cutting away abraded fibers with a pair of Fiskars 6"spring-loaded scissors and comparing sample weights before and after abraded fibers are removed.
Specifically, the Fiber Lock Fuzz test is performed by providing 8 inches (203 mm) cross direction x 10 inches (254 mm) machine direction extrusion coated samples; clamping the samples such that they remain flat during double rolling; double rolling the samples in the machine direction 15 times at a constant speed and at about a 45° angle using the Velcro roller discussed above in this evaluation; using a 2 inches x 2 inches (51 mm x 51 mm) sample cutter attached to a press punch certified by National Analytical Equipment Federation (NAEF) to provide two test specimens for each sample; weighing and recording the sample weights for each sample to 0.1 mg using a calibrated AE200 balance; carefully removing all abraded fiber using a pair Fiskars 6" spring-loaded scissors while avoiding cutting any part of a fiber loop; reweighing and recording the two test samples; and taking the difference in weight before and after removal of the abraded fiber as the Fiber Lock Fuzz Number (FLFN). Note that Fiber Lock Fuzz numbers relate inversely to Velcro Numbers; that is, whereas higher Velcro numbers are desirable as indicative of improved abrasion resistance, lower Fuzz numbers indicate improved abrasion resistance. Lamination strength was given a qualitative rating, dependent on the ability of a person to pull apart the carpet structure.
Examples 1-18 Swatches of"Vocation 26"from Shaw Industries, nylon face fiber, 26 oz/yd2 (0.9 kg/m) fiber weight, tufted loop pile, single stitch greige good carpet were cut on slip sheeted onto Kraft paper for each example and polymer was extrusion coated on to the back side of the carpet. The swatches were either used as delivered from the manufacturer, still containing normal surface fiber/yarn processing lubricants, or the
swatches were first washed. In the carpet washing process, swatches were hosed off for 5-10 minutes with building water and allowed to air dry. No secondary backing was added to the carpet which was then extrusion coated. After coated samples were aged for at least 24 hours, tuft bind, abrasion resistance, and delamination were measured.
The extrusion coating performance of ESI I (DS 300 type resin) and ESI/EO blends were compared to EO 1 (Dow XU-59400.00). Results for Examples 1-18 are attached in Table 3: Carpet Extrusion Coating Results. Note that all examples showed good lamination strengths.
Table 3. Example # Melt Temp °C Carpet Formulation Coating Wt. oz/yd2 (kg/m2) Tuft Bind Ib (kg) Fuzz No. Velcro Comp. Expt. 1 500 Washed P I 4.3 (0.15) 7.9 (3.6) na na Comp. Expl. 2 500 Washed P I 8.0 (0.27) 7.9 t3. 6) 9 Comp. Expl. 3 500 Washed P I 10.6 (0.36) 8.9 (4.0) 20 9 Comp. Expt4 500 Washed P I 10.9(0.37) 12.1(5.5) 35 9 Example 1 500 Washed ESI 1 5.4(0.18) 7.4 (3.4) 39 8 Example 2 500 Washed ESI 1 8.0 (0.27) 9.3(4.2) 23 9 Example3 500 Washed ESI 1 10.0(0.34) 10.5(4.8) 50 8 Example 4 500 Washed ESI 1 14.(0.49)6 12.1(5.5) 15 9 Example 5 500 Washed 70 wt percent ESI I 1/30 wt percent P 2 4.6 (0.16) 5.8 (2.6) 30 9 Examplc 6 500 Washed 70 wt percent ESI I/30 wt percent P 2 4.0 (0-14) 6.0 (2.7) 20 9 Examplc 7 550 UN-Washed ESI I 3.8 (0.13) 3.9 (1.8) 135 6 Exampte 8 550 UN-Washed ESI I 7.8 (0.26) 9.5 (4. 3) 57 8 Gaample 9 550 UN-Washed ESI I 9.8 (0.33) 9.9 (4.5) 120 7 Example 10 550 UN-Washed ESI I 11.7 (0.40) 12.3 (5.6) 240 4 Example 11 550 Washed ESI I 3.5 (0.12) 6.3 (2.9) 34 9 Exampíc le 550 Washed ESI I 8.3(0.56) 10.3 (4.7) 27 9 Hxan) 13 550 Washed ESI I 10.9(0.37) 12.5 (5.7) 30 9 Example14 550 Washed ESI I 17.0 (0.58) 11.1(55.0) 40 8 Gxamph li 550 UN-Washed 70 wt percent ESI I/30 wt percent P 2 6.0 (0.20) 6.8 (3. 1) 7 Example 16 550 UN-Washed 70 wt percent ESI I/30 wt percent P 2 6.9 (0.23) 5.0 (2.3) 240 4 Example 17 550 Washed 70 wt percent ESI I/30 wt percent P 2 8.3 (0.56) 6.9 (3.1) 20 9 Example 18 550 Washed 70 wt percent ESI I/30 w percent P 2 5.2 (0.18) 10.0 (4.5) 26 9
Good coating performance (at equivalent weights) was noted with the substantially random ethylene/styrene interpolymer resins compared to the comparative ethylene/octene resins. We have surprisingly found that coating with relatively high molecular weight (6g/lOm I,) ethylene/styrene interpolymers (ESI-1) results in carpet with good tuft bind weights and abrasion resistance compared to the low molecular weigh (30 g/lOm I,) P-l ethylene/octene resin needed for equivalent performance. This is demonstrated by the higher Velcro numbers for the ethylene/styrene interpolymer-coated samples. Also, good penetration of polymer into the interior of yarn and a locking together of individual fibers is required to achieve good abrasion resistance. For good yarn penetration with ethylene/octene resins, low molecular weight, or high melt index resins are needed. The good coating obtained for higher molecular weight, or lower melt index ethylene/styrene interpolymer resins was unexpected.
Comparing Example 2 to Comparative Experiment 2, further surprisingly shows that at equivalent coating weights, especially lower coating weights, the evaluated ethylene/styrene interpolymer resins showed improved tuft bind performance over ethylene/octene resins as shown by their higher tuft bind weights.
Also while bending and rolling up the samples to assess handling and installability of respective extrusion coated carpets, Example 2 showed greater flexibility and less elastic recovery compared to Comparative Experiment 2 again demonstrating the superiority of ethylene/styrene interpolymer-coated samples over the best ethylene/octene resin-coated samples for broadloom carpet.
Finally the data for Examples 5-6 and 15-18 show that it is possible to blend ethylene/styrene interpolymers and ethylene/octene resins together and extrusion coat the resulting blend on a carpet and still have good performance.
EXAMPLES 19-20 To assess the installability of extrusion coated carpets of ethylene/styrene interpolymers relative to SBR-latex mastics standard in the carpet industry and obtained from Shaw, samples taken from the previous examples were further evaluated in an installation, or glue down, test as follows: Several 2 inch x 10 inch (5.1 cm x 25.4 cm) specimens were cut from selected samples of the coated carpet prepared in the previous examples. Shaw Subset 1000 latex mastic was applied to Eterboard concrete boards with a 1/8 inch (0.3 cm) V-notch trowel, and was allowed to dry to the touch. Carpet samples were installed on top of the boards and adhesive, and the samples were allowed to cure for a week at ambient conditions. For testing, the front 2 inches of an installed carpet strip was pulled up (or scraped up) from the board, placed in the grips of an MTS tensile tester, and the peel strength of the remaining 8 inches (20.3 cm) of glued down sample was measured. A sample of commercially available 26 oz/yd2 (0.88 kg/m2) nylon face fiber, latex backed carpet with a secondary woven secondary backing, was also compared to extrusion coated samples. The following table shows the results.
Table 4: Glue Down Performance Example # Previous Example # Backing Type Peei Stren, th lb Used (kg) Example19 Example 3 ESI 1 34 (15.4) Example 20 Example 18 70 percent ESI I/30 9 (4.1) percent P 2 Comp. Expt. 5 Comp Expt. p 1 1 (0.4) Comp. Expt. 6 N/A Shaw SBR Latex 35 (15.9) Example 19 surprisingly shows that an ethylene/styrene interpolymer-bonding surface has excellent adhesion with incumbent carpet glues and offers significant improvement over an ethylene/octene resin-bonding surface as shown by comparing the results with Comparative Experiment 5, and even has comparable bonding compared to commercially available latex backed carpet as shown by comparing the
results with Comparative Experiment 6. Also comparison of the result for Example 20 with that of Comparative Experiment 5 shows that even blends of ethylene/styrene interpolymers and ethylene/octene resins have improved bonding compared to ethylene/octene resins alone. The good glue down performance obtained with ethylene/styrene interpolymers indicates that these materials are also suited as an adhesion promotion material or co-applied layer when added on top of a different backing material.
Examples 21-22 Carpet tile were also prepared from compression molded sheets of CaC03- filled ethylene/styrene interpolymers formulation which were applied both to samples made for previous examples. The molded sheets were prepared via the following steps: 1) Haake bowl mixing and 2) compression molding into plaques. The mixer used for the examples was a Haake mixer equipped with a Rheomix 3000 bowl. All components of the blend were added to the mixer, and the rotor was operated at 190°C, 40 rpm for 10-15 minutes. Material was then dropped out of the Haake.
Extrudate was then cut and compression molded into 3.175 mm thick x 101.6 mm x 101.6 mm plaques with a Pasadena Hydraulics Incorporated (PHI) press. The press was operated at 205°C in a preheat mode at minimal pressure for 3 minutes, and was then was pressured up to 15 tons for 2 minutes. Plaques were then removed from the heat and cooled at 15 tons for 3 minutes.
Carpet tiles were made by cutting the resulting plaques in to 8 inch x 10 inch (20.3 cm x 25.4 cm) dimensions, placing them on the back side of extrusion coated carpet and placing a 30 pound weight in an 10 inch x 10 inch (25.4 cm x 25.4 cm) pan on top of the filled ethylene/styrene interpolymers plaques. This stack was then placed in a convection oven set at 140°C for one half hour. After the time in the oven, samples were removed from the oven, weights were removed, and the samples were allowed to cool to room temperature. Table 5 describes the samples.
Table 5: Carpet Tile Description Example # Base Sample Plaque Formulation Plaque Weight Added on Carpet 21 10 30 percent ESI 2/70 120 ounce/yd2 percent CaCO3 (4.1 kg/nr) 22 4 40 percent ESI 2/60 108 ounce/yd2 percent CaCO, (3.7 kg/m2)
Samples from both examples surprisingly exhibited good flexibility and conformability despite the high levels of filler. Note that the filled layer could have been added via extrusion coating, sheet lamination, via roll milling/calendering, or even could have been applied as a hot melt.
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