Abstract: In a fastener product made of a synthetic resin such as a slide fastener, a separable fastener and a snap tape comprising an attachment part and an engagement part, at least the engagement part is made of a hydrolysis-resistant synthetic resin. Preferably, the hydrolysis-resistant synthetic resin is polyester having a carbodiimide-based hydrolytic stabilizing agent incorporated therein. In a slide fastener having a pair of fastener tapes and coupling elements fixed to the longitudinal edges of the fastener tapes, they are made of a hydrolysis-resistant synthetic resin material. When the slide fastener further comprises upper and lower stop members, a pin-and-box separator, a pair of reinforcing sheet-like members, sewing threads and core cords, they are made of the hydrolysis-resistant synthetic resin material.

Abstract: A method for making linear materials for fasteners, particularly monofilaments, which possess pearly luster and retain this pearly luster intact even after being dyed. A polyester, particularly polyethylene terephthalate, is blended with 1 to 10% by weight of polypropylene and the resultant blend is subjected to melt spinning. The undrawn filament thus obtained possesses pearly luster and can be used as a raw material for fastener parts presenting an appearance of high quality. The undrawn filament has the dyeability thereof adjusted without noticeably affecting the degree of shrinkage when it is drawn at a temperature in the range of from 70 to 98.degree. C. Thus, the monofilaments for fasteners, which possess pearly luster and are allowed to be dyed in colors harmonized with the colors of fastener tapes, can be produced.

Abstract: Linear materials for fasteners, particularly monofilaments, which possess pearly luster and retain this pearly luster intact even after being dyed and a method for the production thereof are disclosed. A polyester, particularly polyethylene terephthalate, is blended with 1 to 10% by weight of polypropylene and the resultant blend is subjected to melt spinning. The undrawn filament thus obtained possesses pearly luster and can be used as a raw material for fastener parts presenting an appearance of high quality. The undrawn filament has the dyeability thereof adjusted without noticeably affecting the degree of shrinkage when it is drawn at a temperature in the range of from 70.degree. to 98.degree. C. Thus, the monomiflaments for fasteners which possess pearly luster and are allowed to be dyed in colors harmonized with the colors of fastener tapes can be produced.