Coilable polyvinyl chloride products and methods and compositions for producing the same

As a product of manufacture, coilable polymeric pipe, capable of being installed under ground by being plowed in and suitable for natural gas transmission at low ambient temperatures, in the form of a continuous tubular body of a homogeneous fusion blend comprising

• polyvinyl chloride having a Fikentscher K-value of 60-80 as determined in 1% cyclohexanone at 25.degree.C.;
• chlorinated polyethylene in an amount equal to 4-12% of the weight of said polyvinyl chloride, said chlorinated polyethylene having a chlorine content of 30-55% by weight and a melt viscosity in poises/1000 of 20-30;
• an additional polymeric material as a processing aid-secondary modifier in an amount equal to 0.5-6% of the weight of said polyvinyl chloride, having a heat distortion temperature of at least 155.degree.F., and selected from the group consisting of methyl methacrylate homopolymer;
• copolymers of methyl methacrylate and lesser amounts of a lower alkyl acrylate;
• mixtures of said homopolymer and copolymers;
• acrylonitrile-butadiene-styrene copolymers containing 20-30% by weight acrylonitrile, 15-30% by weight butadiene and 40-65% by weight styrene;
• mixtures of said acrylonitrile-butadiene-styrene copolymers with lesser amounts of at least one additional polymeric material selected from the group consisting of said methyl methacrylate homopolymer and copolymers and ethylene-vinyl acetate copolymers containing 10-30% by weight vinyl acetate;
• copolymers of vinyl chloride with an alkyl vinyl ether in which the alkyl group contains 8-18 carbon atoms, said copolymers containing 60-99.5% by weight vinyl chloride and 0.5-40% by weight alkyl vinyl ether;
• and polymers produced by grafting vinyl chloride onto an ethylene-vinyl acetate copolymer to produce a polymer containing 40-60% by weight ethylne-vinyl acetate;
• and a minor proportion of a finely divided inorganic filler selected from the group consisting of titanium dioxide and zinc oxide,
• the amount of said filler being in the range of 0.25-1% for titanium dioxide and 0.5-2% for zinc oxide, based on the weight of said polyvinyl chloride;
• said pipe having
• an impact strength at 0.degree.C. of at least 85 ft. lbs. as determined for 2 inch O.D. pipe by the ASTM TUP drop test,
• an apparent tensile strength of at least 7000 p.s.i. as determined by Canadian Standards Association test CSA B1374--Plastic Pipe for Gas Service, Item 5.5, and
• a heat distortion temperature of at least 155.degree.F. as determined by ASTM D648-56 at 264 p.s.i.,
• said pipe being sufficiently flexible to be coiled into coils of 4 feet dia., for 1/2 inch O.D. pipe, and 8 feet dia., for 2 inch O.D. pipe, and uncoiled from such coils at 0.degree.F., without damage to the pipe.