FIELD OF THE INVENTION

[0001] This invention relates to pipe made by extruding a post-chlorinated polyvinyl chloride (CPVC) compound having CPVC resin together with a narrowly defined amount of additives. The pipe produced with this CPVC compound has a very high Hydrostatic Design Basis (HDB) which results in a higher pressure rating for the pipe at a given wall thickness compared to a lower HDB material, and/or a thinner wall pipe will have the same pressure rating as a thicker wall pipe made from a lower HDB material. The CPVC compounds of this invention have a HDB classification of 1 ,600 psi, as defined by ASTM D2837 at 180°F. The material allows a CPVC pipe of standard dimension ratio of 1 1 (SDR-11) to have a pressure rating of 160 psig pressure rating at 180°F.

BACKGROUND OF THE INVENTION

[0002] CPVC pipe has enjoyed great commercial success mainly because of its excellent physical and chemical properties. CPVC pipes are also simple to install in a plumbing system. The CPVC pipes also have excellent corrosion resistance, which allows their use in many industrial installations to transport corrosive fluids. CPVC pipes have also found a large use in dwellings to replace copper pipes for hot and cold water distribution systems and for fire sprinkler systems.

[0003] U.S. Patent 5,194,471 ('471) teaches a CPVC composition for making pipes which has a HDB classification of 1,000 psi. The composition of the '471 patent requires from 5-15 parts by weight per 100 parts by weight of CPVC resin of impact modifier and from 1-5 parts by weight per 100 parts by weight of CPVC resin of chlorinated polyethylene.

[0004] U.S. Patent Application U.S. 2009/01 10858 Al teaches a CPVC composition for making pipes which has a HDB classification of 1,250 psi. The composition of Backman et. al. requires from 5-6 parts by weight per 100 parts by weight of CPVC resin of impact modifier, from 1-3 parts by weight per 100 parts by weight of CPVC resin of chlorinated polyethylene, and 1.3-3.5 parts by weight per 100 parts by weight of CPVC resin of wax.

[0005] Both of the above prior references require at least 1 part by weight of chlorinated polyethylene per 100 parts by weight of CPVC resin in the CPVC composition.

[0006] Hydrostatic design basis "HDB" of a composition used to make pipe is used to specify the long term internal pressure a pipe can operate with. HDB is the estimated circumferential tensile stress in the wall of the pipe that when applied continuously will cause the pipe to withstand rupture or burst for 100,000 hours (ASTM D2837-01).

[0007] The term "SDR" refers to "standard dimensions ratio" of a pipe. SDR is defined as: [D ₀ /t] where "D ₀ " is the average outside diameter of the pipe, and "t" is the minimum wall thickness.

[0008] The pressure rating of the pipe is determined by the formula:

2 x HDB rating of the material x safety factor

SDR-1

[0009] For an SDR (standard dimension ratio)- 1 1 pipe made with CPVC that has a 1,000 psi classification and for which the safety factor is 0.5, the pressure rating is: 100 psig = (1 ,000 psi)/(l 1 -1 ). If the same SDR-1 1 pipe is tested with a material that has a HDB classification of 1 ,600 psi, the pressure rating is (1 ,600 psi)/(l 1 -1 ) = 160 psig, that is 60% higher than with a material that has a HDB of 1 ,000 psi classification. The safety factor, also known as service design factor, is specified in TR-9/2002 of the Plastic Pipe Institute (PPI). The safety factor for CPVC water pipes is specified as 0.5 by PPI for calculating pressure rating of pipe. Thus, the safety factor used in this specification and claims is 0.5 in all examples.

[0010] The HDB classification is determined at the 100,000 hour intercept, as measured according to ASTM D2837-01 at 180°F. For a composition to have a 1,600 psi HDB classification, it must have a minimum HDB of 1,530 psi on the test (ASTM D- 2837-01). HDB is determined by long term hydrostatic stress rupture testing (LTHS).

[0011] Another important property of CPVC pipe is the cell class of the CPVC composition used to make the pipe. The cell class should be at least 2-3-4-4-7 and can be a higher cell class of 2-4-4-4-8. The first number "2" in the cell class designation specifies a CPVC compound; the second numeral (whether "3" or "4) specifies the level of notched Izod impact strength; "3" indicates at least 80.1 J/m (1.5 ft lb. /in.) of notch; "4" indicates at least 266.9 J/m (5 ft. lb./in.) of notch; the third numeral "4" specifies tensile strength of at least 48.3 MPA (7,000 psi); the fourth numeral "4" specifies tensile modulus of at least 2482 MPa (360,000 psi); and the fifth numeral (whether "7" or "8") specifies the level of heat distortion temperature (HDT) measured under 1.82 MPa (264 psi) load. Numeral "7" indicates HDT of at least 100°C, and "8" indicates HDT of at least 1 10°C (see ASTM D1784). HDT is also referred to as heat distortion temperature under load or DTUL.

[0012] Most CPVC pipe currently sold meets the cell classification requirements (2-3-4-4-7) of ASTM D2846. The pipe's HDB of 1,000 psi (6.89 MPa) at 100,000 hr. provides a less than optimal margin of safety for the performance of pipe required to meet a demand for continuous service under stated conditions of elevated pressure (690 KPa (100 psig), and temperature, 82.2°C (180°F), over a period of 50 years.

[0013] If the CPVC compound could be reformulated to provide pipe with a 60% higher pressure rating than required (HDB of 1,600 psi vs. HDB of 1,000 psi, then the pipe could provide the higher margin of safety. On the other hand, if the user was satisfied with the margin of safety afforded by the requirements of ASTM D2846, then the user could make the pipe thinner (wall thickness) and thus a higher SDR. A pipe with a thinner wall thickness and the same outside diameter would provide higher flow and lower pressure drop than a thicker wall thickness pipe. The pipe would also be lighter in weight and require less CPVC material to produce the pipe.

[0014] It would be very desirable to have a CPVC pipe made with a CPVC compound having a HDB of 1,600 psi classification.

SUMMARY OF THE INVENTION

[0015] The obj ective of the present invention is to make a CPVC pipe which has a very high pressure rating at typical wall thickness or a normal pressure rating at less wall thickness than normal.

[0016J The obj ective is accomplished by making the pipe from a CPVC composition meeting a hydrostatic design basis (HDB) classification of 1 ,600 psi at the 100,000 hour intercept, as measured according to ASTM D2837-01 at 180°F. The CPVC pipe also has a cell class of at least 2-3-4-4-7. The CPVC composition has a tensile strength greater than 3,700 psi at 180°F, preferably greater than 4,050 psi and a tensile modulus greater than 650 psi at 180°F, preferably greater than 700 psi . The tensile strength and modulus are measured according to ASTM D638. The CPVC composition contains 100 parts by weight of CPVC resin, with small amounts of impact modifier, wax, stabilizer, and optionally process aid.

[0017] The level of impact modifier, wax, stabilizer and process aid (if present) are critical to making a CPVC composition having a HDB classification of 1 ,600 psi. Too much of an ingredient will cause the HDB to drop below the desired 1 ,600 psi level and too little of an ingredient will not allow the composition to be satisfactorily processed into a pipe. The inventor has found a critical level of each ingredient and combination of ingredients which give the desired HDB classification of 1 ,600 psi for the CPVC composition while maintaining the processability of the composition and meeting the cell class of 2-3-4-4-7.

[0018] All levels of ingredients in the CPVC composition herein are expressed as parts by weight per 100 parts by weight of CPVC resin. The level of ingredients in the CPVC composition should meet at least one of the following:

a) The level of impact modifier plus the level of process aid is less than 6 parts by weight;

b) The level of impact modifier plus the level of wax is less than 6 parts by weight;

c) The level of impact modifier plus the level of stabilizer is less than 6 parts by weight;

d) The level of process aid plus the level of wax is less than 4 parts by weight; e) The level of process aid plus the level of stabilizer is less than 3 parts by weight;

f) The level of wax plus the level of stabilizer is from 2 to 3.5 parts by weight; g) The level of impact modifier plus a level of process aid plus a level of wax is less than 8 parts by weight;

h) The level of impact modifier plus the level of process aid plus the level of stabilizer is less than 7 or from 8 to 10 parts by weight;

i) The level of process aid plus the level of wax plus the level of stabilizer is less than 5.5 parts by weight;

j) The level of impact modifier plus the level of wax plus the level of stabilizer is less than 7.75 parts by weight; or

k) The level of impact modifier plus the level of process aid plus the level of wax plus the level of stabilizer is less than 9.5 parts by weight.

[0019] In one embodiment, an important feature of the CPVC composition can be that the composition is substantially free of chlorinated polyethylene. By substantially free means there is less than 1.0 part by weight of chlorinated polyethylene, preferably less than 0.5 part by weight and most preferably the CPVC composition is free of chlorinated polyethylene.

[0020] Sections of the CPVC pipe can be joined together to form a piping system. The CPVC pipe sections can be joined together with CPVC pipe fittings and solvent cement or by using mechanical couplings.

[0021] The CPVC pipe can be made in any of the normal SDR sizes, such as but not limited to SDR-7, SDR-9, SDR-1 1, SDR-13.5, SDR-17, SDR-21, SDR-26 and SDR-32 in dimensions as specified in ASTM F442 for iron pipe size ("IPS") or ASTM D2846 for copper tube size ("CTS"). The CPVC pipe can also be made to the dimensions as specified in ASTM F441, such as Schedule 40 or Schedule 80.

DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS

[0022] Exemplary embodiments in accordance with the present invention will be described. Various modifications, adaptations or variations of the exemplary embodiments described herein may become apparent to those skilled in the art as such are disclosed. It will be understood that all such modifications, adaptations or variations that rely upon the teachings of the present invention, and through which these teachings have advanced the art, are considered to be within the scope and spirit of the present invention.

[0023] The methods, polymers and compositions of the present invention may suitably comprise, consist of, or consist essentially of the components, elements, steps, and process delineations described herein. The invention illustratively disclosed herein suitably may be practiced in the absence of any element which is not specifically disclosed herein.

[0024] Unless otherwise stated, all part levels of the ingredients of the CPVC composition are based on 100 parts by weight of CPVC resin. The abbreviation term CPVC means "chlorinated polyvinyl chloride". The term PVC means "polyvinyl chloride".

[0025] The term pipe includes the term "tube" as used in ASTM D2846 when specifying dimensions for copper tube size (CTS) tubes and also includes pipes made to dimensions of iron pipe size (IPS). The term "pipe" as used herein includes CTS and IPS pipes and tubes.

[0026] Here, as well as elsewhere in the specification and claims, individual numerical values or range limits of ingredients, can be combined to form additional non-disclosed and/or non-stated ranges or levels of ingredients of the CPVC

composition.

[0027] The first necessary ingredient of the CPVC composition is CPVC resin. The CPVC resin is present at 100 parts by weight, and all other ingredients are based on levels per 100 parts by weight of CPVC resin. The CPVC resin used has a weight percent of chlorine of from 65 to 70 wt. %, preferably from 66 to 68 wt. %. The CPVC resin is made from a PVC resin having an I.V., measured as stated in ASTM D1243 of from 0.80 to 1.05, preferably from 0.86 to 0.96, and most preferably from 0.88 to 0.92. The process for making CPVC resin from PVC resin are described in U.S. Patent Nos., 2,996,049; 3,100,762; and 5,591,497, the disclosures of which are incorporated by reference herein as if fully set forth herein. The preferred CPVC composition has at least 85 wt. %, and preferably at least 88 wt. % of the composition as CPVC resin. The wt. % chlorine in the CPVC resin will affect the HDT (heat distortion temperature), as measured according to ASTM D648, of the CPVC composition. In general with all other ingredients of the CPVC composition being constant, the HDT will be higher when the chlorine content of the CPVC resin is higher.

[0028] The PVC resin used to make the CPVC resin is readily available in the market place from several suppliers, including Oxy Vinyls, ShinTech, Axiall, and is normally sold as pipe grade PVC resin.

[0029J The second necessary ingredient of the CPVC composition is an impact modifier. Suitable impact modifiers include ABS and MBS graft copolymers. ABS impact modifiers are usually prepared by grafting styrene and acrylonitrile monomers onto polybutadiene rubber or onto a styrene-butadiene rubber substrate. A blend of two or more impact modifiers can be used. The amount of impact modifier is at least 2.5 parts by weight and preferably at least 3.5 parts by weight.

[0030] MBS impact modifiers are graft copolymers generally prepared by polymerizing methyl methacrylate or mixtures of methyl methacrylate with other monomers in the presence of polybutadiene or polybutadiene-styrene rubbers.

[0031] Acrylic impact modifiers can also be used.

[0032] Further information of the above impact modifiers can be found in the Second Edition of the Encyclopedia of PVC, edited by Leonard I. Nass, Marcel Dekker, Inc., the contents which is incorporated by reference herein.

[0033] The third necessary ingredient of the novel CPVC composition is at least one heat stabilizer. A blend of two or more stabilizers can be used. Organotin stabilizers are currently the most recognized heat stabilizers. These stabilizers include alkyl tin mercaptides, alkyl tin carboxylate and alkyl tin maleate. Stabilizers based on a composition of mono and dialkyl tin (2-ethyl hexyl mercapto acetate systems) are suitable. Optionally, a co-stabilizer can be used in conjunction with the stabilizer.

Co-stabilizers, if used in conjunction with the main stabilizer, are used in small amounts, such as from 0.1 to 1.0 part by weight per 100 parts by weight of CPVC resin, and preferably from 0.1 to 0.5 parts by weight. Suitable co-stabilizers include salts of carboxylic acids, disodium phosphate, sodium citrate, zeolite and hydrotalcite. The amount of heat stabilizer used is at least 1.0 part by weight, and preferably at least 1.5 parts by weight.

[0034] The CPVC compound can also include a non-organometallic heat stabilizer, or non-tin stabilizer for short. The stabilizer can comprise, consist essentially of, or consist of 1) an organic based stabilizer, and 2) a co-stabilizer system. By "consist essentially of it is meant that the compound may include some small amount of other stabilizer in amounts insignificant to the stabilization of the product, generally in the range of less than lphr, or less than 0.75 phr or less than 0.5 phr, or even less than 0.25 phr. The term "phr" refers to parts by weight per 100 parts by weight of CPVC resin. In some embodiments the compound is essentially free of metallic stabilizers, such as organotin stabilizers.

[0035] In simplest terms, organic based stabilizers (OB-Stabilizers) are non-metal containing stabilizers based on organic chemistry. While the OB-Stabilizers suitable for the stabilizer system herein are not particularly limited, the most prevalent OB-Stabilizer compounds today include uracil and its derivatives. A common derivative of uracil suitable as an OB-Stabilizer for the composition herein is 6-amino-l,3-dimethyluracil.

[0036] In general, the OB-Stabilizers can be included in the composition at levels required to meet physical properties, such as color. The OB-Stabilizers can be present in an amount of from about 0.05 or 0.1 to about 2.0 parts by weight per 100 parts by weight of said CPVC resin. In some embodiment, the OB-Stabilizers can be present from about 0.15 to about 1.75 phr, or from about 0.2 to about 1.5 phr, or even from about 0.25 or 0.5 to about 1.25 phr.

[0037] The co-stabilizer system can comprise, consist essentially of, or consist of at least one zeolite, at least one C6 to Cn metal carboxylase, or combinations thereof.

[0038] The co-stabilizer system can include an effective amount of at least one zeolite. Zeolites comprise basically a three dimensional framework of Si0 ₄ and A10 ₄ tetrahedra. The tetrahedra are crosslinked through the sharing of oxygen atoms so that the ratio of oxygen atoms to the total of the aluminum and silicon atoms is equal to 2. This relationship is expressed as 0/(Al+Si)=2. The electrovalence of the tetrahedra containing aluminum and silicon is balanced in the crystal by the inclusion of a cation. For example, the cation can be an alkali or alkaline earth metal ion. The cation can be exchanged for another depending upon the final usage of the aluminosilicate zeolite. The spaces between the tetrahedra of the aluminosilicate zeolite are usually occupied by water. Zeolites can be either natural or synthetic.

[0039] The basic formula for all aluminosilicate zeolites is represented as follows:

M2 _/ nO [Al203] _x [Si0 ₂ ]y [H20] _z wherein M represents a metal, n represents the valence of the metal and X and Y and Z vary for each particular aluminosilicate zeolite. Essentially it is believed that any aluminosilicate zeolite can be used as a stabilizer in the instant invention, provided that the ratio of the silicon to aluminum in such aluminosilicate zeolite is less than 3.0 and that the aluminosilicate zeolite can be incorporated into the CPVC compound.

Preferably, the zeolite ratio of silicon to aluminum in such aluminosilicate zeolite is less than 1.5. Most preferably, the ratio of silicon to aluminum in such aluminosilicate zeolite is about 1.

[0040] Example zeolites which can be used in the instant invention include but are not limited to zeolite A, described in U.S. Pat. No. 2,822,243; zeolite X, described in U.S. Pat. No. 2,822,244, zeolite Y, described in U.S. Pat. No. 3, 130,007; zeolite L, described in Belgian Pat. No. 575, 1 17 zeolite F, described in U.S. Pat. No. 2,996,358; zeolite B, described in U.S. Pat. No. 3,008,803; zeolite M, described in U.S. Pat. No. 2,995,423; zeolite H, described in U.S. Pat. No. 3,010,789; zeolite J, described in U.S. Pat. No. 3,01 1,869; zeolite P, described in U.S. Pat. No. 3,532,459, and zeolite W, described in U.S. Pat. No. 3,102,853.

[0041] The preferred zeolites can include, alone or in combination with another Group I metal, hydrated silicates of aluminum incorporating sodium, of the type mNaO xA CbySiCh ζ¾0. These preferred zeolites include zeolites type A, P, X, and Y.

[0042] As a sole stabilizer, the zeolite can generally be present at from about 0.1 to about 4.0 phr. In some embodiments, the zeolite can be present from about 0.25 to about 3.5 phr, or 0.5 to about 3.0 phr. In a preferred embodiment, the zeolite can be present from about 0.75 to about 1.5 or 2.5 phr.

[0043] The co-stabilizer system can also include a metal carboxylate. The C6 to Cn metal carboxylate can be a metal salt of a saturated C6, or C7, or C ₈ to Cn, or C12 aliphatic carboxylate or di -carboxylate, an unsaturated C6 to C12 aliphatic carboxylate or di -carboxylate, a saturated C6 to C 12 aliphatic carboxylate or di-carboxylate substituted with at least one OH group, or whose chain is interrupted by at least one oxygen atom (oxyacids), or a cyclic or bicyclic carboxylate or di-carboxylate containing from 6, or 7, or 8 to 1 1 or 12 carbon atoms. Suitable metals for the metal carboxylate can include Li, K, Mg, Ca, and Na. [0044] Preferably the C6, or C ₇ or Cs to Cn or C12 metal carboxylate is a sodium carboxylate, most preferably a disodium carboxylate, such as disodium sebacate, disodium dodecanedioate or disodium suberate, and combinations thereof. Other examples of Ce to C12 metal carboxylates that may be employed include disodium adipate, disodium azelate, and disodium undecanedioate.

[0045] The Ce to Cn metal carboxylate can be present from about 0.1 to about 4.0 phr. In some embodiments, the Ce to C12 metal carboxylate can be present from about 0.25 to about 3.0 phr, or 0.5 to about 2.5 phr. In a preferred embodiment, the C6 to Cn metal carboxylate can be present from about 1.0 to about 2.0 phr. The metal carboxylate can be dry blended with other ingredients of a compound or the CPVC resin can be coated with a metal carboxylate solution by a wet coating process followed by drying to obtain a metal carboxylate coated CPVC resin.

[0046] When in combination, the zeolite and C6 to C12 metal carboxylate can be present at levels that do not negatively affect the ability of the CPVC compound to meet physical property limitations and that avoid moisture foaming. In one embodiment the weight ratio of zeolite to the C6 to C12 metal carboxylate can be between about 6: 1 to 1 :6. In another embodiment, the weight ratio of zeolite to C6 to C12 metal carboxylate can be from about 5 : 1 to 1 :5, or 4: 1 to 1 :4, or even 3 : 1 to 1 :3. In some preferred embodiments the weight ratio of zeolite to C6 to C12 metal carboxylate can be from about 2: 1 to 1 :2, or even 1 : 1 .

[0047] When employing a combination of zeolite and Ce to C12 metal carboxylate, the co-stabilizer system can be present at levels that do not negatively affect the ability of the CPVC compound to meet physical property limitations and that avoid moisture foaming. Generally, the co-stabilizer combined system can be present from about 0. 1 to about 7.0 phr, more preferably 0.5 to about 6.0 phr, or 0.75 to about 5.0 phr. In some embodiments, the combined co-stabilizer system can be present from about 1 .0 to about 4.0 phr, and more preferably 1 .25 to about 3.0 phr.

[0048] In one embodiment, other co-stabilizers beside zeolite and carboxylate may also be employed in the co-stabilizer system. In an embodiment, the stabilizer system is essentially free of, or free of heavy metal stabilizers, such as tin stabilizers. By essentially free of it is meant that a minor portion may be present in amounts that do not contribute or contribute an insignificant amount to stabilization. In another embodiment, the stabilizer can include a heavy metal stabilizer, such as, for example, a tin stabilizer.

[0049] For most purposes, the stabilizer system including both the OB-Stabilizers and the co-stabilizer system can be present in amount of from about 0. 1 to about 7.0 or 8.0 phr. Preferably, the stabilizer system of the combination can be present at about 0.5 to about 6, or from about 0.75 to about 5.0. In some embodiments, the stabilizer system including both zeolite and Ce to C12 metal carboxylate can be present in amount of from about 1.0 to about 4.5, or even 1.25 to about 3.0 or 4.0 phr.

[0050] The fourth necessary ingredient of the CPVC composition is wax. Suitable wax includes polyglycerols of di- and tri-oleates, polyolefins, such as polyolefins and oxidized polyolefin and high molecular weight paraffin. The preferred wax is a blend of oxidized polyethylene, paraffin, and a Fischer-Tropsch wax. The amount of wax used is at least 0.5 part by weight, preferably at least 0.75 part by weight.

[0051] In addition to the above listed four necessary ingredients the CPVC composition can also contain optional ingredients that function as process aids and colorants. Suitable process aids include acrylic polymers, such as poly methylacrylate and chlorinated polyethylene as well as SAN polymers.

[0052] The CPVC composition, in some embodiments, should be substantially free of chlorinated polyethylene (CPE) as it lowers the HDB of the CPVC composition. By the term "substantially free" of CPE it is meant that the level should be less than 1 .0 part by weight, preferably less than 0.5 part by weight, and most preferably the level of CPE should be zero. That is, the most preferred embodiment is that CPE is absent from the CPVC composition.

[0053] Colorants, such as titanium dioxide, carbon black and other coloring pigments may be used, provided they are small particle size. The particle size of any pigments used should be sub-micron in size, that is, less than 1 micron in size, and preferably less than 0.5 micron.

[0054] To achieve the 1 ,600 psi HDB rating for the CPVC composition requires that a very specific level of a combination of the essential ingredients, plus the process aid (if present) be used. Too high of a combined level of ingredients will cause the HDB to drop below the 1 ,600 psi classification and too low of a level of the combined ingredients will not allow the CPVC composition to be satisfactorily processed into a pipe. ¾ has been found that the combination levels of ingredients should meet at least one of the following:

a) the level of impact modifier plus the level of process aid should be less than 6 parts by weight;

b) the level of impact modifier plus the level of wax should be less than 6 parts by weight;

c) the level of impact modifier plus the level of stabilizer should be less than 6 parts by weight;

d) the level of process aid plus the level of wax should be less than 4 parts by weight;

e) the level of process aid plus the level of stabilizer should be less than 3 parts by weight;

f) the level of wax plus the level of stabilizer should be from 2 to 3.5 parts by weight;

g) the level of impact modifier plus the level of process aid plus the level of wax should be less than 8 parts by weight;

h) the level of impact modifier plus the level of process aid plus the level of stabilizer should be less than 7 parts by weight or from 8 to 10 parts by weight.

i) the level of process aid plus the level of wax plus the level of stabilizer should be less than 5.5 parts by weight;

j) the level of impact modifier plus the level of wax plus the level of stabilizer should be less than 7.75 parts by weight; or

k) the level of impact modifier plus the level of process aid plus the level of wax plus the level of stabilizer should be less than 9.5 parts by weight. All the levels in (a) - (k) above are based on 100 parts by weight of CPVC resin.

[0055] Any combination of a) through k) can be employed in the present technology. In one embodiment, the composition can comprise, consist essentially of, or consist of the levels of ingredients of at least two of the combinations of a) through k). In another embodiment, the composition can comprise, consist essentially of, or consist of the levels of ingredients of at least three of the combinations of a) through k). In a still further embodiment, the composition can comprise, consist essentially of, or consist of the levels of ingredients of at least four of the combinations of a) through k). In some

embodiments, the composition can comprise, consist essentially of, or consist of the levels of ingredients of at least five of the combinations of a) through k). In one embodiment, the composition can comprise, consist essentially of, or consist of the levels of ingredients of at least six of the combinations of a) through k). In embodiments, the composition can comprise, consist essentially of, or consist of the levels of ingredients of at least seven of the combinations of a) through k). In further embodiments, the composition can comprise, consist essentially of, or consist of the levels of ingredients of at least eight of the combinations of a) through k). In still further embodiment, the composition can comprise, consist essentially of, or consist of the levels of ingredients of at least nine of the combinations of a) through k). In even further embodiments, the composition can comprise, consist essentially of, or consist of the levels of ingredients of at least ten of the combinations of a) through k). In an embodiment, the composition can comprise, consist essentially of, or consist of the levels of ingredients of all of the combinations of a) through k).

[0056] In one embodiment, the composition can comprise, consist essentially of, or consist of the levels of ingredients of combinations d), e), h), and i). In one embodiment, the composition can comprise, consist essentially of, or consist of the levels of ingredients of combinations a), b), c), d), f), g), h), i), j) and k). In another embodiment, the composition can comprise, consist essentially of, or consist of the levels of ingredients of combinations a), b), c), d), e), g), h), i), j) and k). In further embodiments, the composition can comprise, consist essentially of, or consist of the levels of ingredients of combinations b), c), d), f), g), i), j) and k). In still further embodiments, the composition can comprise, consist essentially of, or consist of the levels of ingredients of combinations a), d), e), g), h), and i). In another embodiment, the composition can comprise, consist essentially of, or consist of the levels of ingredients of combinations a), c), d), e), f), g), h), i), j) and k). In one embodiment, the composition can comprise, consist essentially of, or consist of the levels of ingredients of

combinations b), c), d), f) _» g) _» h), i), j) and k). In another embodiment, the composition can comprise, consist essentially of, or consist of the levels of ingredients of

combinations d), and ί)· In embodiments, the composition can comprise, consist essentially of, or consist of the levels of ingredients of combinations a), d), e), f). g) _> '), and k). In one embodiment, the composition can comprise, consist essentially of, or consist of the levels of ingredients of combinations a), d), e), g), h), i), and k).

[0057] To make a pipe the ingredients of the CPVC composition are combined and mixed in a Henschel mixer, or ribbon blender and either cubed or preferably left in powder form. The powder is fed to either a single, or preferably, a twin screw extruder and extruded at a temperature in the range of from 175°C to 250°C to make the pipe of this invention.

[0058J An extruder generally has a conveying means, such as a hopper, through which the CPVC composition is charged, an intermediate screw processing portion, and a final die through which the CPVC composition is discharged in the form of an extrudate. It is further advantageous to use low friction sizing, such as gauging discs or vacuum sizing sleeves to control the proper dimension of the pipe. Multi-screw extruders are the preferred extruders for extruding the pipe of this invention. The multi-screw extruders can have counter-rotating screws or co-rotating screws. Conical twin screw, four screw and parallel twin screws in use in industry are preferably counter- rotating multi-screw extruders. They are generally gravity or meter fed. The co-rotating screws can be used as compounding machines and sometimes for extrusion of pipe. In most cases, output rates are dependent upon the extruder size, drive power and screw design.

[0059] The CPVC compositions of this invention will have a tensile strength greater than 3,700 psi at 180°F, preferably greater than 4,050 psi at 180°F, and a tensile modulus greater than 650 psi at 180°F, preferably greater than 700 psi at 180°F. The CPVC compositions of this invention will have a heat distortion temperature (HDT) of at least 100°C and preferably at least 1 10°C, as measured on annealed sample. Except for HDT, all other properties are measured on unannealed samples. Since pipe as produced is not normally annealed, a sample specimen can be cut from a pipe and annealed to check the properties of the CPVC composition used to make the pipe. Annealing can be done by exposing the sample to elevated temperatures for extended periods of time. Different times and temperatures can be used to anneal a sample, as long as the internal stresses to the material resulting from processing is relieved. To evaluate the CPVC composition for HDT properties before it is made into a pipe, the material is first molded into a plaque and a specimen is cut from the plaque and annealed as stated above. [0060] The pipe made with the CPVC composition of this invention meets the cell class 2-3-4-4-7 and also can meet cell class 2-4-4-4-8. The pipe made with the CPVC composition of this invention also meets the requirements of 1600 HDB (at least 1,530 HDB).

[0061J The pipes made by the current invention can be any of the SDR sizes. The pipe can have any of the dimensions specified in ASTM F442 for IPS pipes or ASTM D2846 for CTS pipes. The pipe can also have dimensions as specified in ASTM F441 which includes Schedule 40 and Schedule 80 pipes. SDR-11 is the most common size CPVC pipe for transporting water in homes, apartment buildings, and commercial buildings. SDR-13.5 CPVC pipe is used in fire sprinkler applications. Schedule 40 and 80 are frequently used in industrial applications to transport various chemicals.

[0062] Piping systems can be made by using multiple lengths of the pipe, together with couplers having various angles. The lengths of pipe are joined together by the coupler, which is called pipe fittings, to create a piping system. The pipe can be joined to a CPVC fitting by the use of a solvent cement. The solvent cement is CPVC resin dissolved in a mixture of solvents and can have thickening agents added to the mixture. Solvent cements for CPVC pipes are readily available from hardware stores and plumbing supply stores. A mechanical fitting can also be used to join the lengths of CPVC pipe. Mechanical fittings are well known in the plumbing field and are readily available from plumbing supply merchants. Mechanical fittings are typically made with a metal body and use rubber seals to make them water tight.

[0063] The invention will now be demonstrated with examples, which are not intended to be limiting but show the best mode of the invention.

EXAMPLES 1-5 (COMPARATIVE)

[0064] Examples 1-5 are comparative examples that do not meet the requirements set out in the claims. They represent either a HDB that does not meet the 1600 classification or are too low in tensile and/or modulus. In all examples the CPVC composition was extruded into pipe and measured for HDB at 180°F at the 100,000 hour intercept. Table I

Example No.

1 2 3 4 5

Ingredient Level (Parts by Weight)

66 wt. % CI CPVC Resin 100 - - - -

67 wt. % CI CPVC Resin - 100 100 100 -

68 wt. % CI CPVC Resin - - - - 100

MBS Impact Modifier - 4.0 5.5 7.0 6.0

Acrylic Impact Modifier 4.25 - - - -

CPE Process Aid - 6.0 3.0 6.0 3.0

Acrylic Process Aid 2.0 - - - -

Oxidized PE Wax 0.83 0.83 0.58 0.33 0.90

Fischer-Tropsch Wax 0.83 .083 0.58 0.33 0.90

Paraffin Wax 0.83 0.83 0.58 0.33 0.90

Dibutyl Tin Stabilizer 1 .25 3.0 2.0 1.0 -

Dioctyl Tin Stabilizer - - - - 1.5

Ti0 ₂ Pigment 4.0 4.0 4.0 4.0 4.0

Combination Levels of Two Ingredients

Impact Modifier + Process Aid 6.25 10.0 8.5 13.0 9.0

Impact Modifier + Wax 6.74 6.49 7.24 7.99 8.7

Impact Modifier + Stabilizer 5.50 7.0 7.5 8.0 7.5

Process Aid + Wax 4.49 8.49 4.74 6.99 5.7

Process Aid + Stabilizer 3.25 9.0 5.0 7.0 4.5

Wax + Stabilizer 3.74 5.49 3.74 1.99 4.2

Combination Levels of Three Ingredients

Impact Modifier + Process Aid +

Wax 8.74 12.49 10.24 13.99 1 1.7

Impact Modifier + Process Aid +

Stabilizer 7.50 13.0 10.5 14.0 10.5

Impact Modifier + Wax + Stabilizer 7.99 9.49 9.24 8.99 10.2

Process Aid + Wax + Stabilizer 5.74 1 1 .49 6.74 7.99 7.2 Table I

Example No.

1 2 3 4 5

Combination Levels of Four Ingredients

Impact Modifier + Process Aid +

Wax + Stabilizer 9.99 15.49 12.24 14.99 13.2

[0065] Comparative examples 1-5 did not meet the minimum requirement for a 1,600 psi HDB classification (1530).

EXAMPLES 6-15

[0066] Examples 6-15 are presented to show compositions of this invention which meet the HDB classification of 1 ,600 psi.

Table ΠΙ

Example No.

6 7 8 9 10 11 12 13 14 15

Ingredient Level (Parts by Weight)

66 wt. % CI CPVC

Resin - 100 100 100 - - - - - -

67 wt. % CI CPVC

100 - - 100 100 - - - - Resin -

68 wt. % CI CPVC

Resin - - - - - - 100 100 100 - Table ΠΙ

Exam lie No.

6 7 8 9 10 11 12 13 14 IS

65.25 wt. % C1

- - - - - - - - - 100 CPVC Resin

MBS Impact

7.0 3.5 3.5 - 4.0 4.0 - 6.0 - 5.0 Modifier

Acrylic Impact

- - - 4.25 - - 4.0 - 6.0 - Modifier

CPE Process Aid - 2.0 - 2.0 - - - - - -

Acrylic Process

- - - - - - 3.0 3.0 - - Aid

PE Wax - - - - - - - - - 0.6

Oxidized PE Wax 0.83 0.33 0.83 0.33 0.33 0.83 0.33 0.33 0.33 0.8

Fischer-Tropsch

0.83 0.33 0.83 0.33 0.33 0.83 0.33 0.33 0.33 1.1 Wax

Paraffin Wax 0.83 0.33 0.83 0.33 0.33 0.83 0.33 0.33 0.33 -

Zeolite Stabilizer - - - - - - - - - 1.5

Dibutyl Tin

3.0 1.25 - - 3.0 1.0 - 2.0 1.5 - Stabilizer

Dioctyl Tin

- - 1.7 1.7 - - 1 .5 - - - Stabilizer

T1O2 Pigment 4.0 4.0 4.0 4.0 4.0 4.0 4.0 4.0 4.0 3.5

Combination Levels of Two Ingredients

Impact Modifier +

7.0 5.5 3.5 6.25 6.0 4.0 7.0 9.0 6.0 5.0 Process Aid

Impact Modifier +

9.49 4.49 5.99 5.24 6.99 6.49 4.99 6.99 6.99 7.5 Wax

Impact Modifier +

10.0 4.75 5.2 5.95 9.0 5.0 5.5 8.0 7.5 6.5 Stabilizer

Process Aid + Wax 2.49 2.99 2.49 2.99 0.99 2.49 . 3.99 3.99 0.99 2.5

Process Aid +

3.0 3.25 1 .70 3.70 3.00 1 .0 4.5 5.0 1.5 1.5 Stabilizer

Wax + Stabilizer 5.49 2.24 4.19 2.69 3.99 3.49 2.49 2.99 2.49 4.0

Combination Levels of Three Ingredients Table ΠΙ

Example No.

6 7 8 9 10 11 12 13 14 15

Impact Modifier +

9.49 6.49 5.99 7.24 6.99 6.49 7.99 9.99 6.99 7.5 Process Aid + Wax

Impact Modifier +

Process Aid + 10.0 6.75 5.2 7.95 9.0 5.0 8.5 1 1.0 7.50 6.5 Stabilizer

Impact Modifier +

12.49 5.74 7.69 6.94 9.99 7.49 6.49 8.99 8.49 9.0 Wax + Stabilizer

Process Aid + Wax

5.49 4.24 4.19 4.69 3.99 3.49 5.49 5.99 2.49 4.0 + Stabilizer

Combination Levels of Four Ingredients

Impact Modifier +

Process Aid + Wax 9.99 7.74 7.69 8.94 9.99 7.49 9.49 11.99 8.49 9.0 + Stabilizer

RESULTS

[00671 All of examples 6-15 meet the classification of 1,600 psi (1,530 or greater) for HDB at the 100,000 hour intercept, and have good tensile strength and modulus at 180°F.

[0068] In the foregoing description, certain terms have been used for brevity, clarity and understanding, however, no unnecessary limitations are to be implied therefrom, because such terms are used for descriptive purposes and are intended to be broadly construed. Moreover, the descriptions and examples herein are by way of examples and the exemplary embodiment is not limited to the exact details shown and described. The description of the exemplary embodiment included in the Abstract included herewith shall not be deemed to limit the invention to features described therein.

[0069] Having described the features, discoveries and principles of the invention, the manner in which it is formulated and operated, and the advantages and useful results attained, the new and useful compositions, combinations of ingredients and relationships are set forth in the appended claims.