GB830442A - Improvements in or relating to the production of shaped articles, particularly filaments, of synthetic polymers by melt extrusion processes - Google Patents

Abstract

Shaped articles, particularly filamentary materials, comprise a core of a synthetic polymer containing amine end groups and a surrounding contiguous sheath of a synthetic polymer essentially free from amine end groups, at least one of the polymers having fibreforming characteristics. A polymer "containing amine end groups" is defined as a polymer in which the proportion of amine end groups is 50 or more equivalents per 106 g. of polymer, and a polymer "essentially free from amine end groups" is defined as a polymer containing fewer than 50 amine end group equivalents per 106 g. of polymer. The articles may be made by simultaneously extruding through the same orifice the molten polymer containing amine end groups as a core and the molten polymer essentially free from amine end groups as a surrounding sheath. The preferred polymers are the polyamides, particularly polyhexamethylene adipamide. Polyureas derived from a diisocyanate and a diamine, polythioureas, polythioamides, polysulphonamides, polyimides, poly-4-amino-1,2,4-triazoles and copolyesteramides may also be used. The core-forming and/or the sheath forming polymer may be a blend of two or more polymers. Thus the amine content of the core polymer may arise from a blend of a polymer containing amine groups and another polymer with few or no amine groups as, for example, a blend of a polyamide and a polyester, such as polyethylene terephthalate. While polymers containing primary amine end groups are preferred, polymers containing secondary and tertiary amine end groups may also be used. Thus an N-amino-alkyl morpholine can be used as a viscosity stabilizer in the preparation of polyamides in order to obtain polymers with tertiary amine end groups. In order to obtain a product which can be dyed with acid dyes, the overall amine concentration in the two-component filament should be 80-400, preferably 100-200, equivalents of amine end groups per 106 grams of polymer. In an example, a polyhexamethylene adipamide containing 26 and 135 equivalents of carboxyl and amine end groups, respectively, per 106 grams of polymer is spun as the core of a two-component fibre simultaneously with a polyhexamethylene adipamide having 43 and 74 equivalents of amine and carboxyl end groups, respectively, per 106 grams of polymer as the sheath component, using the apparatus described in Specification 830,441. The pump speeds for the two components are adjusted to give a sheath-core weight ratio of 30/70 and the polymers are spun at 285 DEG C. Two component synthetic fibres made according to the invention can be dyed deep fast colours with acid dyes. Specifications 639,893, 687,036 and U.S.A. Specification 2,130,948 also are referred to.