Abstract: A novel composition comprises a block copolymer of a polyetheramide, e.g., poly-(4,7-dioxadecamethylene adipamide) and a random copolymer resulting from the polymerization of an ether free polyamide precursor, e.g., hexamethylenediamine salt of adipic acid and a precursor of a polyetheramide. The block copolymer can be more easily processed into useful articles such as fiber and film because it differs structurally from a corresponding block copolymer of homopolymers of polyetheramide and polyamide.

Abstract: Improved melt blending process for preparing block copolymer of poly(4,7-dioxadecamethylene adipamide)-polycaprolactam, which is also known as N-30203-6//6, involves continuing the melt blending until the polymer is characterized in that the maximum amount of the block copolymer recovered from an aqueous formic acid solution containing the dissolved block copolymer exceeds about 90%. Fiber prepared from such a characterized block copolymer does not fuse when scoured in boiling water.

Abstract: Process for preparing block copolymer involves dry blending salt of a prepolyamide, e.g. a 30203-6 salt, and particules of melt-spinnable polyamide. Blend is heated to a temperature in the range of between from the melting point of higher melting component to below amide-interchange temperature of a blend of the melt-spinnable polyamide and the homopolymer which would result from the polymerization of the salt. Heating and mixing are continued until substantially all of the salt and the polyamide are converted into a block copolymer. The latter can be used to make fibers.

Abstract: Process for forming block copolymer involves mixing dry salt of a prepolyamide and a molten melt-spinnable polyamide. Mixture is heated to a temperature in the range of between from the melting point of higher melting component of the mixture to below amide-interchange temperature of a blend of the melt-spinnable polyamide and the homopolymer which would result from the polymerization of the salt. Mixing and heating is continued until substantially all of the salt and the polyamide are converted into a block copolymer. The latter can be used to make fibers. One example of a suitable salt is a 30203-6 salt.