TIRE MONOFILAMENTS AND PROCESS FOR THEIR MANUFACTURE

摘要

1385804 Polyester filaments HOECHST AG 13 Dec 1972 [14 Dec 1971] 57463/72 Heading B5B A high molecular weight aromatic polyester monofilament, especially polyethylene terephthalate, is made from a raw material having an intrinsic viscosity greater than 0À67 (at 25‹ C. in a 3 : 2 mixture of phenol and tetrachloro-. ethane) and containing less than 25 milliequivalents/Kg of terminal carboxy groups; the raw material is spun into a water bath, drawn in water at 70‹-100‹ C. in a ratio of 1 : 4À0 to 1 : 6À0, further drawn at 15‹ C. or less below its melting point to a total ratio of 1 : 6À0 to 1 : 7À5, and set at 15‹ C. or less below its melting point allowing a maximum shrinkage of 5%. Setting may be performed immediately after the further draining, both operations being performed either in the same infrared heated chamber, or in separate chambers linked by a heated conveyer. A preferred raw material is a copolymer containing at least 80% of ethylene terephthalate units, together with for example isophthalic, p.p1-diphenyl-dicarboxylic, p,p1-diphenyl-methyl-dicarboxylic, and p,pl-diphenylsulpho-dicarboxylic acids, naphthalene-dicarboxylic acids hexahydroterephthalic, adipic, and sebacic acids. The heating for the second drawing step is provided by baths of high-boiling inert liquid, metal baths, ball beds, hot air, or infrared or high frequency radiation. The monofilament produced has an intrinsic viscosity of more than 0À64, less than 30 milliequivalents/kg. of terminal carboxy groups, a diameter of 0À20-0À55 mm., a specific strength of more than 60 g./tex., an elongation at break of 6À0 to 15À0%, an elongation of less than 6À0% at a load of 27 g/tex and a thermoshrinkage of less than 8À0% at 160‹ C. The monofilament is used for tyres, conveyer belts, and power transmission belts, and is resistant to hydrolysis, heat, and the action of rubber chemicals.