COPOLYESTER FIBERS AND FILAMENTS HAVING DEFINED SHRINKING PROPERTIES

摘要

1297603 Copolyester filaments FARBWERKE HOECHST AG 11 May 1971 [14 May 1970] 14149/71 Heading B5B Filaments of a terpolymer of terephthalic acid, ethylene glycol and 2,2-dimethyl-propanediol-1,3, containing 1 to 20% by weight of the terpolymer of dimethylpropylene units, and having a degree of shrinkage in boiling water of at most 20% and in a hot gas (e.g. air) of from 20% to 60% at 200‹ C. may be prepared by wetting drawn filaments of the terpolymer with water or steam and drying them at a temperature of from 80‹ to 160‹ C. without permitting shrinkage and thereafter optionally heat treating the filaments in a relaxed condition at a temperature of from 120‹ to 140‹ C. Preferably the filaments contain 3 to 7% by weight dimethylpropylene units and have a degree of shrinkage in boiling water of at most 2 % and in a hot gas of from 35-45%. The preferred degrees of shrinkage are illustrated in the curves of Figs. 1 (for boiling water) and 2 (for hot air) (not shown). In examples a terpolymer containing 5% by weight of dimethylpropylene units is melt spun into filaments which are drawn in steam at a ratio of 3À7 and dried in air or on heated drums at 140‹ C., 100‹ C. and 80‹ C. The filaments are then crimped and cut into fibres. In Examples 3 and 4 the crimped filaments are heated in steam at 130‹ C. prior to being cut into staple.