GB1116745A - A method of manufacturing polyamide composite filaments having a crimpability - Google Patents

Abstract

1,116,745. Crimpable polyamide composite filaments. KANEGAFUCHI BOSEKI KABUSHIKI KAISHA. 27 Sept., 1965 [26 Sept., 1964; 4 Nov., 1964; 30 Jan., 1965], No. 41028/65. Heading B5B. Composite filaments having a high crimp potential and consisting of two components eccentrically disposed with respect to each other are made by melt extruding simultaneously through the same orifice of a spinneret a homopolyamide having an inherent viscosity of not less than 0À8 and a copolyamide having an inherent viscosity not less than 1À2 and not less than that of the homopolyamide, the copolyamide being in a " balanced melting pointviscosity relationship " with the homopolyamide, the difference between the melting points of the polymers being not more than 80‹ C., at least 75% by weight of the copolyamide being derived from an amide monomer which has been copolymerised with not less than 3% by weight of at least one copolymer. The term " intrinsic viscosity " is defined in accordance with the formula wherein [#] represents the intrinisic viscosity of the polymer, # represents the viscosity of a solution of the polymer in m-cresol at 30‹ C, # o represents the viscosity of pure m-oreaol at 30‹ C., # sp represents the specific viscosity of the polymer and C represents the concentration of the solution of the polymer in meta-cresol expressed as grams of polymer per 100 c.c. of the solution. The expression " balanced melting point-viscosity relationship " is defined as a relationship in which the homopolyamides and the copolyamides satisfy the formula wherein [# o ] represents the arithmetic mean of the intrinsic viscosities of the two types of polymers, #[#] represents the difference between their intrinsic viscosities, and #(mP) represents the difference between their melting points. The homopolyamide may be a polycapramide or a polyhexamethylene adipamide. The principal constituent of the copolyamide may have the recurring unit -HN-(CH 2 ) 5 -CO- and the copolymeric constitutent may be isophthalamide having the recurring unit wherein n is 6 to 12. The copolyamide may have carbonamide as a second copolymeric constituent having the recurring unit wherein X, X<SP>1</SP> represent oxygen, sulphur, CH 2 , -N=N- or and m 1 , m 2 , m 3 and m 4 represent 0 to 6. The filaments may be caused to develop crimp by immersing them under light load in water at 100‹ C.