An improved dewaxing aid for solvent dewaxing process comprising a mixture of (A) an .alpha.-olefin polymer having an average molecular weight of from about 10,000 to 1,000,000 and a wide molecular weight distribution exceeding the range of from about 10,000 to 1,000,000 but falling within the range of from about 2,000 to 3,000,000 wherein the .alpha.-olefin polymer is a homopolymer made up of a C.sub.10 to C.sub.25 alpha-olefin monomer or is a copolymer made up of a monomer mixture comprising more than 50 wt. % of at least 2 C.sub.10 to C.sub.25 alpha-olefin monomers and a melt index greater than 1.8 g/10 min. and (B) an olefin vinyl acetate copolymer having a vinyl acetate content of from about 15 to 40 wt. % and an average molecular weight of from about 50,000 to 1,000,000 and a melt index greater than 2 g/10 min. The .alpha.-olefin polymer having a high molecular weight and wide molecular weight distribution, when combined with the olefin-vinyl acetate copolymer, synergistically improves the efficiency of wax separation.
CROSS-REFERENCE TO RELATED APPLICATIONS
This application is a Continuation-in-Part of U.S. Ser. No. 233,380, filed Feb. 11, 1981, now abandoned, which is a Continuation-in-Part of U.S. Ser. No. 184,921, now abandoned, filed Sept. 8, 1980, which is a Continuation under 37 CFR 1.60 of U.S. Ser. No. 102,652, filed Dec. 12, 1979, now abandoned, which is a Continuation under 37 CFR 1.60 of U.S. Ser. No. 36,044, filed May 4, 1979, now abandoned, which is a Division under 37 CFR 1.60 of U.S. Ser. No. 926,811, filed July 21, 1978, now U.S. Pat. No. 4,192,733.
A blend of chlorinated polyethylene with two or more different ethylene/vinyl acetate copolymers is provided. The blend produces a membrane which is suitable for use in single-ply roofing applications. One ethylene/vinyl acetate copolymer has a polymerized vinyl acetate content of from about 38 to about 60 percent by weight of copolymer. A second ethylene/vinyl acetate copolymer has a polymerized vinyl acetate content of from about 13 to about 27 percent of weight of copolymer.
Wax crystals of improved morphology are produced by employing a dewaxing aid in an agitated solvent dewaxing environment, preferably an agitated indirect chilling solvent dewaxing environment, such as an agitated chiller, such as a scraped surface chiller which has been modified so that the scraper is not in contact with the internal wall of the chiller wherein a high degree of agitation is maintained by rotating the paddles to achieve a paddle tip speed of 25 to 400 ft./min. and the gap between the agitator tip and the inner wall of the vessel is about 0.5 to 40% of the internal diameter of the chiller. Agitation in agitated indirect chiller appratus has been shown to produce significantly improved feed filter rates and liquids/solids ratios when employed in conjunction with dewaxing aids in solvent dewaxing processes.
Copolymers of dialkyl fumarate and vinyl acetate having Specific Viscosities of at least 2.5 at 2% polymer concentration in xylene at 40.degree. C., and wherein at least 50 wt. % of said alkyl groups are C.sub.20 to C.sub.24, are useful as dewaxing aids, particularly in propane dewaxing.
