Polyester monofilament with increased hydrolytic stability - obtd. by extruding and stretching from a mixt contg. poly-(1,4-cyclohexane:di:methylene terephthalate) copolymer, fluoro-polymer and antioxidant

摘要

Monofilament with increased hydrolytic stability (I) is claimed, for the prodn of industrial fabrics; (I) is based on a polyester which is approved for contact with food, and is produced by extrusion followed by stretching. (I) consists of a mixt of (A) 100 pts wt polyester of m pt at least 265 deg C, derived from a glycol component contg at least 50 mol% cis- and/or trans-1,4-cyclohexanedimethanol (CHDM) and an acid component contg at least 50 mole% tere-, ortho- or iso-phthalic acid (TPA/OPA/TPA) and/or 1,4-cyclohexane-dicarboxylic acid (CHDCA), and (B) 1-6 pts wt extrudable fluoro-polymer with m pt at least 260 deg C. Prodn of (I) comprises mixing (A) and (B), melting the mixt in a screw extruder at 290-330 deg C, extruding to monofilament, cooling to 80-140 deg C, stretching by 2-7 times in air and/or water at elevated temp but below the m pt, and then opt heat-fixing. USE/ADVANTAGE - The invention provides monofilament for the prodn of heavy-duty industrial woven fabrics, esp for use as freezing belts and drying belts in food mfr. Wrt prior-art fabrics based on polyester fibre, (I) has improved resistance to hydrolysis together with improved strength and elongation properties, resulting in high knot strength, high resistance to buckling and high wear resistance (ie longer service life).