MAKING SAME USING LATEX COATING COMPOSITIONS

Field

[0001] The present invention relates to carpet products and processes for producing the same using latex coating compositions.

Background

[0002] Most conventional carpets comprise a primary backing with yarn tufts in the form of cut or uncut loops extending upwardly from this backing to form a pile surface. For tufted carpets, the yarn is inserted into a primary backing (frequently a woven or nonwoven material) by tufting needles and a precoat (i.e., a binder) is applied thereto.

[0003] Most residential and commercial carpets are also manufactured with a woven scrim (typically made from polypropylene), also referred to as a secondary backing, attached to the back of the carpet to provide dimensional stability. The scrim is attached to the precoated carpet back with another binder formulation typically referred to as a skipcoat or adhesive coating. The skipcoat is applied to the scrim, and the scrim is then applied to the precoated backing of the carpet before the assembled carpet elements are sent into a curing oven. The purpose of the skipcoat or adhesive coating is to provide a layer of material which will adhere the woven scrim to the back of the carpet.

[0004] For both the precoat and the skipcoat, the physical properties of the binders are important to their successful utilization as carpet coatings. In this regard, there are a number of important requirements which must be met by such coatings. The coating must be capable of being applied to the carpet and dried using the processes and equipment conventionally employed in the carpet industry for latex, e.g., emulsion, coating. The binder composition must provide excellent adhesion to the pile fibers to secure them firmly in the backing. In addition, the adhesive properties of the coating composition have to be retained even in the presence of a high loading of fillers, such as calcium carbonate, aluminum trihydrate, barites, cullet, recycled carpet backing, recycled fillers, ground glass, silica, fly ash, and combinations thereof.

[0005] A variety of emulsion polymerization components and techniques can influence binding strength, but, in general, vinyl acetate-ethylene and vinyl acrylic copolymers are known to provide lower binding strength than coating binders comprising styrene butadiene. To compensate for lower tuft bind strength provided by carpet coating compositions comprising vinyl ester based binders, higher binder levels are required, which affects the profitability of carpet made with vinyl ester based coating binders.

[0006] Over the past several years, the prices of styrene butadiene based binders have risen and fallen quite dramatically. Vinyl ester binders have been used as suitable replacements for styrene butadiene based binders in carpet applications but in most cases only for the precoat adhesive layer. The skipcoat adhesive layer, which is used to attach the secondary scrim to the back of the carpet, has remained a styrene butadiene based composition. There is therefore interest in developing vinyl ester binders which can be used to provide at least a partial replacement for styrene butadiene based binders in carpet skipcoat applications.

Summary

[0007] It has now been discovered that by blending a dispersion of a copolymer of at least a vinyl ester of a saturated carboxylic acid having from 1 to 13 carbon atoms and at least 5 wt.% of an alkyl ester of an ethylenically unsaturated carboxylic acid (e.g., vinyl acetate-acrylate copolymer) with a styrene/butadiene (SB) copolymer dispersion, latex coating compositions may be prepared having especially desirable physical properties for use as skipcoat and precoat binders in carpet manufacture. In particular, carpet products having relatively high delamination strengths may be formed using the processes and latex coating compositions of the present invention.

[0008] In one embodiment, the invention resides in a carpet product, e.g., a tufted or woven carpet product, comprising at least one substrate and at least one adhesive layer associated with said at least one substrate, said adhesive layer being formed from an adhesive composition comprising a latex coating composition comprising: (a) a first copolymer of at least styrene and butadiene; and (b) a second copolymer of at least a vinyl ester of a saturated carboxylic acid having from 1 to 13 carbon atoms and at least 5 wt.% of an alkyl ester of an ethylenically unsaturated carboxylic acid, wherein the first and second copolymers are dispersed in an aqueous medium. The latex coating composition may be incorporated into an adhesive composition that functions as a precoat or as a skipcoat binder or as both. Accordingly, the substrate may comprise a primary backing or a secondary backing.

[0009] In another embodiment, the invention resides in a process for forming a carpet product, the process comprising the steps of: (a) providing an adhesive composition comprising a latex coating composition comprising: (i) a first copolymer of at least styrene and butadiene; and (ii) a second copolymer of at least a vinyl ester of a saturated carboxylic acid having from 1 to 13 carbon atoms and at least 5 wt.% of an alkyl ester of an ethylenically unsaturated carboxylic acid, wherein the first and second copolymers are dispersed in an aqueous medium; (b) providing a primary carpet layer comprising yarn tufted into a primary backing; (c) applying the adhesive composition to at least one of the primary carpet layer or a secondary backing; (d) contacting the primary carpet layer with the secondary backing; and (e) drying the adhesive composition under conditions effective to adhere the primary carpet layer to the secondary backing.

[0010] In yet another embodiment, the invention resides in a process for forming a carpet product, the process comprising the steps of: (a) providing an adhesive composition comprising a latex coating composition, comprising: (i) a first copolymer of at least styrene and butadiene; and (ii) a second copolymer of at least a vinyl ester of a saturated carboxylic acid having from 1 to 13 carbon atoms and at least 5 wt.% of an alkyl ester of an ethylenically unsaturated carboxylic acid, wherein the first and second copolymers are dispersed in an aqueous medium; (b) contacting carpet fibers with a primary backing material; (c) applying the adhesive composition to the carpet fibers and the primary backing material; and (d) drying the adhesive composition under conditions effective to adhere the carpet fibers to the primary backing material.

Detailed Description

[0011] Described herein is a carpet product, e.g., a tufted or woven carpet product, comprising at least one substrate, such as a primary and/or secondary backing layer, and at least one adhesive layer associated with the substrate, e.g., directly or indirectly bonded to the substrate, using a latex coating composition comprising at least first and second copolymers dispersed in an aqueous medium. The first copolymer is a copolymer of at least styrene and butadiene, while the second copolymer is a copolymer of at least a vinyl ester of a saturated carboxylic acid having from 1 to 13 carbon atoms and at least 5 wt.% of an alkyl ester of an ethylenically unsaturated carboxylic acid. The latex coating composition surprisingly and unexpectedly provides the carpet product with particularly desirable cohesive characteristics, for example, tuft bind and delamination strength.

[0012] The first and second copolymers used to form the latex coating composition described herein may be made separately in a first dispersion and a second dispersion, respectively, which are then blended together to form the desired latex coating composition.

First Copolymer Dispersion

[0013] The first copolymer dispersion may be formed by the emulsion polymerization of at least styrene and butadiene (SB), and optionally one or more additional co- monomers such as an acrylonitrile (SBA) or an acrylic co-monomer.

[0014] The first copolymer optionally further comprises a co-monomer that acts as an internal crosslinker. For example, the first copolymer optionally further comprises a polyethylenically unsaturated co-monomer selected from the group consisting of triallyl cyanurate, triallyl isocyanurate, diallyl maleate, diallyl fumarate, divinyl benzene and diallyl phthalate. Co-monomers of this type include diallyl maleate, diallyl fumarate and diallyl phthalate. This type of polyethylenically unsaturated co-monomer will be generally present in the first copolymer, if at all, in an amount from 0.05 to 0.5 pphm. Such polyethylenically unsaturated co-monomer(s)/cross-linker(s) may be used in the first copolymer, if at all, in amounts from 0.1 to 0.3 pphm.

[0015] Processes for manufacturing the first copolymer dispersion prior to blending may vary depending on whether the first polymer is SB or SBA. Generally, such first emulsions may be formed through well-known emulsion polymerization techniques, exemplary processes for which are disclosed, for example, in US Patent Nos. 5,288,787; 5,326,853; 5,362,798; and 6,365,647, the entireties of which are incorporated herein by reference.

[0016] The raw materials used to form the first copolymer dispersion, for example, typically include the monomers (styrene and butadiene for SB or styrene, butadiene and acrylonitrile for SBA), water, an emulsifier, an initiator system, a modifier, a free radical scavenger (e.g., dimethyl dithiocarbamate or diethyl hydroxylamine) and a stabilizer system. The polymerization process may be performed batch wise or continuously. In a continuous process, the monomers are metered into the reactor chains and emulsified with the emulsifiers and catalyst. The initiator system may be a redox reaction between, for example, chelated iron and an organic peroxide using a reducing agent, e.g., sodium formaldehyde sulfoxide (SFS). Alternatively, potassium peroxydisulfate may be used as the initiator. The process may be conducted as a cold polymerization process or a hot polymerization process. A mercaptan chain transfer agent may be used to provide free radicals and to control molecular weight distribution. During polymerization, the reaction conditions, e.g., temperature, flow rate, and agitation may be controlled to provide the desired level of conversion.

[0017] The relative amount of monomers for the first copolymer dispersion also may vary. In embodiments where the first polymer is SB, styrene may be present, for example, in an amount from 5 to 60 pphm, such as from 10 to 40 pphm, for example from 20 to 30 pphm, and butadiene may be present in an amount from 40 to 95 pphm, from 60 to 90 pphm, or from 70 to 80 pphm, based on the total monomer in the first copolymer dispersion.

[0018] Where the first polymer is SBA, the styrene may be present, for example, in an amount from 30 to 70 pphm, from 40 to 60 pphm, or from 45 to 55 pphm, the butadiene may be present in an amount from 1 to 40 pphm, from 5 to 30 pphm, or from 10 to 25 pphm, and the acrylonitrile may be present in an amount from 5 to 45 pphm, from 15 to 35 pphm, or from 20 to 30 pphm, all based on the total monomer in the first copolymer dispersion. For further description of SBA and processes for manufacturing SBA, see Harper C.A., Handbook of Plastic and Elastomers, McGraw-Hill, New York (1975), the entirety of which is incorporated herein by reference.

Second Copolymer Dispersion

[0019] The second copolymer dispersion comprises a copolymer of at least a vinyl ester of a saturated carboxylic acid having from 1 to 13 carbon atoms and in excess of 5 wt.% of an alkyl ester of an ethylenically unsaturated carboxylic acid.

[0020] Suitable vinyl esters for use in production of the second copolymer include; vinyl formate, vinyl acetate, vinyl propionate, vinyl butyrate, vinyl isobutyrate, vinyl valerate, vinyl-2-ethyl-hexanoate, vinyl isooctanoate, vinyl nonate, vinyl decanoate, vinyl pivalate, and vinyl versatate. Of the foregoing, vinyl acetate is the preferred monomer because of its ready availability and low cost. In some embodiments, more than one vinyl ester is employed in the polymerization process. For example, in one embodiment, the copolymer may comprise a copolymer of vinyl acetate, vinyl neodecanoate and the alkyl ester of an ethylenically unsaturated carboxylic acid. Generally, the vinyl ester content of the second copolymer will range from about 10 to 95 pphm, such as from 50 to 95 pphm, for example from about 70 to 95 pphm (parts per hundred based on total monomers in the second copolymer).

[0021] Suitable alkyl esters for use in production of the second copolymer comprise alkyl esters and/or hydroxy alkyl esters of ethylenically unsaturated mono- and dicarboxylic acids, especially acrylic, methacrylic and maleic acids, in which the or each alkyl group of the alkyl ester comprises from 1 to 12 carbon atoms. Specific examples of suitable (meth)acrylate monomers include methyl acrylate, ethyl acrylate, butyl acrylate, 2-ethylhexyl acrylate, decyl acrylate, butyl methacrylate, iso-butyl methacrylate, iso-bornyl methacrylate hydroxy ethyl acrylate, hydroxy ethyl methacrylate and combinations of these acrylate monomers. Specific examples of suitable maleate monomers include dimethyl maleate, dibutyl maleate and dioctyl maleate Generally, the alkyl ester content of the second copolymer will range from about 5 to 90 pphm, such as from 5 to 50 pphm, for example from about 5 to 30 pphm (parts per hundred based on total monomers in the second copolymer).

[0022] The second copolymer may further comprise one or more additional functional comonomers, for example, selected from the group consisting of vinyl halides, such as vinyl chloride, ethylenically unsaturated carboxylic acids and the anhydrides and the salts thereof, such as acrylic acid, methacrylic acid, maleic acid and fumaric acid, and vinyl aromatics, such as vinyltoluene and styrene, and combinations of two or several monomers from any of said additional comonomer types. Where present, such additional functional comonomers are preferably added in very low amounts of from 0.1 pphm to 5.0 pphm.

[0023] In addition, the second copolymer may further comprise one or more internal cross-linking monomers, for example, selected from the group consisting of polyethylenically unsaturated monomers, such as diallyl maleate, diallyl fumarate and diallyl phthalate, ethylenically unsaturated silane compounds, such as trialkoxysilanes, ethylenically unsaturated monomers containing epoxy groups, such as glycidyl methacrylate, and ethylenically unsaturated monomers containing one or more amide, hydroxyl or carbonyl groups, such as N-methylol acrylamide. The aforementioned cross-linking monomers will be generally present in the second copolymer, if at all, in an amount from 0.05 pphm to 0.5 pphm.

[0024] In accordance with one embodiment, the second copolymer of the dispersions produced herein for use in carpet manufacture may be prepared to have a T _g of less than 20 ^Q C, such as from about -20 °C to less than 20 °C, as calculated by the Flory-Fox equation.

[0025] The dispersions comprising the second copolymer hereinbefore described can be prepared using conventional emulsion polymerization procedures which result in the preparation of emulsions in aqueous latex form. Such procedures are described, for example, in U.S. Patent No. 5,849,389, the disclosure of which is incorporated herein by reference in its entirety.

[0026] In a typical polymerization procedure, the vinyl acetate and acrylate monomers can be polymerized in an aqueous medium under pressures not exceeding 100 atmospheres in the presence of a catalyst and at least one emulsifying agent. The aqueous system can be maintained by a suitable buffering agent at a pH of 2 to 7, with the catalyst being added incrementally or continuously. More specifically, vinyl acetate and acrylate monomers can be suspended in water. The vinyl acetate and acrylate monomers can then be gradually heated to polymerization temperature.

[0027] The homogenization period is generally followed by a polymerization period during which the catalyst, which comprises a main catalyst or initiator, and may include an activator, is added incrementally or continuously together with the remaining co- monomers, if any, e.g., one or more additional co-monomers. If employed, the one or more additional co-monomers may be added either as pure monomer or as a premixed emulsion.

[0028] Suitable polymerization catalysts include the water-soluble free-radical- formers generally used in emulsion polymerization, such as hydrogen peroxide, sodium persulfate, potassium persulfate and ammonium persulfate, as well as tert-butyl hydroperoxide, optionally in amounts from 0.01 % and 3% by weight, for example, 0.01 % and 1 % by weight based on the total amount of the emulsion. The catalysts can be used together with reducing agents such as sodium formaldehyde-sulfoxylate, ferrous salts, sodium dithionite, sodium hydrogen sulfite, sodium sulfite, sodium thiosulfate, as redox catalysts in amounts from 0.01 % to 3% by weight, for example, from 0.01 % to 1 % by weight, based on the total amount of the emulsion. The free radical-formers can be charged in the aqueous emulsifier solution or be added during the polymerization in doses.

[0029] The manner of combining the polymerization ingredients can be by various known monomer feed methods, such as, continuous monomer addition, incremental monomer addition, or addition in a single charge of the entire amounts of monomers. The entire amount of the aqueous medium with polymerization additives can be present in the polymerization vessel before introduction of the monomers, or alternatively, the aqueous medium, or a portion of it, can be added continuously or incrementally during the course of the polymerization.

[0030] The emulsion polymerization used to prepare the second copolymer in aqueous latex form may be carried out in the presence of a stabilization system which comprises one or more anionic and/or nonionic surfactants as emulsifiers. Such emulsifiers are conventional and well known. Suitable nonionic surfactants which can be used as emulsifiers in the emulsion stabilizing system of the second emulsion or blended latex coating composition described herein include polyoxyethylene condensates.

[0031] A wide variety of nonionic surfactants of this type are disclosed in the hereinbefore referenced U.S. Patent No. 5,849,389. Suitable anionic surfactants which can be used as emulsifiers in the emulsion stabilizing system of the second copolymer dispersion or blended latex coating compositions described herein include alkyl aryl sulfonates, alkali metal alkyl sulfates, sulfonated alkyl esters and fatty acid soaps.

[0032] Various protective colloids, such as polyvinyl alcohol and cellulose ethers, have been used to stabilize vinyl ester/acrylate dispersions, instead of or in addition to the surfactant emulsifiers. In the present application, to reduce compatibility issues with the first copolymer dispersion, the second polymer dispersion is generally substantially free of protective colloids or at least contains no more than 0.5 pphm of protective colloid.

[0033] The second copolymer within the dispersions prepared herein may generally have a mean particle diameter, dw, ranging from 150 to 600 nm. The copolymer within the dispersions prepared for use with tufted carpets will generally have a mean particle diameter, dw, ranging from 200 to 600 nm. The viscosity of the dispersion may range from 200 to 2,000 mPas, as measured with a Brookfield viscometer at 25 °C.

Latex Coating Composition

[0034] A latex coating composition suitable for use as an adhesive layer in carpet applications can be produced by blending the first and second copolymer dispersions described above. The relative amounts of the first copolymer and the second copolymer in the blended latex coating composition may vary depending, for example, on the desired characteristics for the carpet product as well as whether the latex coating composition is intended for use in a precoat, a skipcoat or both. In one embodiment, the blended latex coating composition comprises the first copolymer in an amount from 5 to 99 wt.%, such as from 20 to 90 wt.%, for example from 50 to 85 wt.%, such as from 70 to 80 wt.% and the second copolymer in an amount from 1 to 95 wt.%, such as from 10 to 80 wt.%, for example from 15 to 50 wt.%, such as from 20 to 30 wt.%, based on the total weight of all copolymers in the blended latex coating composition.

[0035] In one embodiment, the latex coating composition may also comprise one or more external crosslinkers. Suitable external crosslinkers include carbonates such as ammonium zirconium carbonate (AZC) and potassium zirconium carbonate (KZC). The external crosslinker may be added to the first copolymer dispersion, before or after blending of the first and second copolymer dispersions to form the blended latex coating composition. If present, the external crosslinker may be present in the latex coating composition in an amount from 1 to 10 wt.%, e.g., from 3 to 10 wt.%, based on the total weight of the blended latex coating composition.

[0036] Before or after blending, the solids content of the aqueous polymer dispersions can be adjusted to the level desired by the addition of water or by the removal of water by distillation. Generally, the desired level of polymeric solids content is from 40 wt.% to 70 wt.% based on the total weight of the emulsion, for example, from 40 wt.% to 60 wt.% or from 45 wt.% to 55 wt.%.

[0037] In addition to the latex coating composition hereinabove described, the final carpet adhesive may contain a variety of conventional additives in order to modify the properties thereof. Among these additives may be included fillers, thickeners, catalysts, dispersants, colorants, biocides, antifoaming agents, etc. In particular, the ability to load the adhesives with high amounts of fillers, such as calcium carbonate, aluminum trihydrate, barites, cullet, recycled carpet backing, recycled fillers, ground glass, silica, fly ash, and combinations thereof, improves the flame retardency and low smoke properties of the adhesive. Preferred adhesives are loaded with filler to yield a composition comprising from about 10 to about 50 weight percent copolymer, and from about 50 to about 90 weight percent filler, based on total weight of the composition, depending in part on the type and form of the carpet being constructed.

[0038] The viscosity of the adhesive composition may vary widely depending primarily on the desired use of the composition. In general terms, the adhesive composition may have a viscosity ranging from 2,000 to 60,000 cP. Lower viscosities, e.g., from 4000 to 15000 cP, may be desired for adhesive compositions for use in precoat applications, while higher viscosities, e.g., from 10,000 to 18,000 cP, may be desired for coaters using a roller and pan process, and viscosities from 25,000 to 45,000 cP or higher may be desired for Tilitson-type coaters and for skipcoat applications, as measured with a Brookfield viscometer at 25 °C.

[0039] The extent or tenacity to which the yarn is affixed to a carpet backing material is referred to as "tuft bind" strength. Carpets with sufficient tuft bind strength exhibit good wear resistance and have longer service lives. In order to have good performance characteristics, 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 the fibers leads to good abrasion resistance. Moreover, in addition to good tuft bind strength and abrasion resistance, the adhesive material may impart or allow good flexibility to the carpet in order to facilitate installation of the carpet. In one embodiment, the blended latex coating composition may be used in an adhesive composition, e.g., carpet precoat or skipcoat binder, to form a carpet composition having a tuft bind value greater than 4.5 Ibf (20 N).

[0040] Since tuft bind values may vary depending on carpet type, the tuft bind strength may be characterized as a "tuft bind percentage" relative to a similar carpet formed using a coating composition containing the first emulsion (not blended with the second emulsion). In this aspect, the blended latex coating compositions of the invention may provide carpeting having a tuft bind percentage of at least 90%, for example, at least 95%. [0041] The strength of the adhesive bond between the scrim and the carpet backing provided by the skip coat layer can be measured by a delamination test such as that described in ASTM D 3936-05. In one embodiment, the blended latex coating compositions of the invention may provide a carpet having a delamination strength of at least 3.5 Ibf (15.6 N), such as 4.0 Ibf (17.8 N). Since delamination values may vary depending on carpet type, the delamination strength may be characterized as a "delamination percentage" relative to a similar carpet formed using a coating composition containing the first emulsion (not blended with the second emulsion). In this aspect, the blended latex coating compositions of the invention may provide carpeting having a delamination percentage greater than 75%, for example, greater than 85% or greater than 90%. In particular, such delamination percentages may be achieved when the blended latex coating composition comprises the first copolymer in an amount from 99 to 30 wt.% and the second copolymer in an amount from 1 to 70 wt.%, based on the total weight of all copolymers in the blended latex coating composition.

[0042] The invention will now be more particularly described with reference to the following non-limiting Examples, in which all parts are by weight unless otherwise indicated.

EXAMPLE 1

[0043] A vinyl acetate-acrylic copolymer comprising 88 wt.% vinyl acetate and 12 wt.% butyl acrylate ("VA-Ac") was used as a partial replacement for styrene-butadiene latex ("SBR") in carpet skipcoat formulations. The SBR binder and blends listed below were filled with 400 parts calcium carbonate and thickened to 10,000 cps. The finished compounds were then poured into dishes to make films and the films were tested for tensile and elongation properties. The tests were performed on 1 inch wide samples with an Instron machine using a separation rate of 12 inches per minute at 70-72 ^Q F (21 - 22 ^Q C). Measured values of grams force at break were converted to psi based on the thickness and width of the samples. The results are summarized in Tables 1 and 2.

Table 1 . Dry Testing

Table 2. After 20 minute soak in room temperature water

[0044] Tensile and elongation values for the compounded films are an indication that the tuft binds and delamination values for the blends will be comparable to the SBR control samples.

Tuft Bind Testing

[0045] When a coating composition herein is to be used as a precoat to lock tufts into a primary backing substrate, a tuft bind test can be used to evaluate the effectiveness of the composition as a precoat. This test measures the amount of force (in lb _/ ) that is required to pull a tuft through the primary tufting substrate. Testing is done similar to ASTM D1335-05 but with certain minor changes. Individual tufts are hooked with a metal device, and this device is placed in top jaw of an Instron apparatus. The carpet is then attached to the bottom jaw of the Instron. The jaws are separated at a rate of 12 inches per minute.

Delamination Testing

[0046] When a coating composition herein is to be used as a skip coat or adhesive coating to attach a scrim as a secondary backing to the back of precoated carpet, a delamination test can be used to evaluate the effectiveness of the composition as the skip coat or adhesive coating. This test measures the adhesive strength property of the carpet coating in securing the polypropylene secondary backing by testing the force required to separate the coated carpet from the polypropylene secondary backing. This test is conducted on an Instron machine in a manner similar to ASTM D 3936-05. The clamps of the Instron are separated at a rate of 12 inches per minute, and the average force required to separate the polypropylene secondary backing from the coated carpet is measured and recorded. Table 3. Performance Data

[0047] The data suggests that up to 70% of the SB can be replaced to provide a blend having a delamination percentage greater than 80% and a delamination strength of at least 3.5 Ibf, which is the minimum needed for many commercial carpet specifications.

EXAMPLE 2

[0048] A vinyl acetate-acrylic copolymer dispersion comprising 90 parts by weight of vinyl acetate (VA), 10 parts by weight of dioctyl malleate (DOM) and 0.25 parts by weight of acrylic acid (AA) was blended with a commercially available styrene-butadiene latex ("SBR"), sold under the trade name Styron LXC 8476NA. The blend comprised 50 parts by weight of the vinyl acetate-acrylic copolymer and 50 parts by weight of the SBR. The blend and each of the base copolymers were filled with 400 parts calcium carbonate per 100 parts by weight of the dry polymer and the resultant samples were then poured into dishes to make films. The films were tested for their tensile properties both before and after a 20 minute soak in room temperature water. The tests were performed on 1 inch wide samples with an Instron machine using a separation rate of 12 inches per minute at 70-72 ^Q F (21 -22 ^Q C). Measured values of grams force at break were converted to psi based on the thickness and width of the samples. The results are summarized in Table 4.

EXAMPLE 3

[0049] A vinyl acetate-acrylic copolymer dispersion comprising 94.3 parts by weight of vinyl acetate (VA), 5.7 parts by weight of dioctyl malleate (DOM) and 0.25 parts by weight of acrylic acid (AA) was blended with a commercially available styrene-butadiene latex ("SBR"), sold under the trade name Styron LXC 8476NA. The blend comprised 50 parts by weight of the vinyl acetate-acrylic copolymer and 50 parts by weight of the SBR. The blend and each of the base copolymers were filled with 400 parts calcium carbonate per 100 parts by weight of the dry polymer and the resultant samples were then poured into dishes to make films. The films were tested for their tensile properties both before and after a 20 minute soak in room temperature water. The tests were performed on 1 inch wide samples with an Instron machine using a separation rate of 12 inches per minute at 70-72 ^Q F (21 -22 ^Q C). Measured values of grams force at break were converted to psi based on the thickness and width of the samples. The results are summarized in Table 4.

Table 4

[0050] The results in Table 4 show a synergistic effect with the SB and VA/DOM copolymer blends having increased tensile strength properties as compared with each of the base copolymers alone.

[0051] While the illustrative embodiments of the disclosure have been described with particularity, it will be understood that various other modifications will be apparent to and can be readily made by those skilled in the art without departing from the spirit and scope of the disclosure. Accordingly, it is not intended that the scope of the claims appended hereto be limited to the examples and descriptions set forth herein but rather that the claims be construed as encompassing all the features of the patentable novelty which reside in the present disclosure, including all features which would be treated as equivalents thereof by those skilled in the art to which the disclosure pertains.