A method for producing a polyamide excellent in appearance after heating is provided. The method for producing a polyamide contains the heating of a composition including a diamine represented by a formula (1), a dicarboxylic acid and a solvent, removing the solvent during and after the heating of the composition or after the heating of the composition, and adding a basic compound and/or a base generating agent to the composition during the heating of the composition and/or before the heating: wherein X is a hetero atom, and n is an integer of 0 to 5. The ring portion including X represents a cyclic structure including X.

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Disclosed in the present invention is poly(ester amide)s and method for preparing thermoplastic poly(ester amide)s therefor. The poly(ester amide)s are prepared using diamine or alkamine as initiator, with diacid and dialcohol-based cyclicester as the monomer, in the catalyst, and by cascade polycondensation-coupling ring-opening polymerization. The obtained poly(ester amide)s have good mechanical properties, solvent resistance and thermal stability. It effectively solves the deficiencies in the current poly(ester amide)s, such as low crystallization temperature and poor heat resistance of polyester parts, and low modulus and rigidity from polyamides part. For aliphatic poly(ester amide)s, they are biodegradable. By means of altering such factors as the ratio of ester bonds and amide bonds and polymer molecular weight and distribution, the performance of the poly(ester amide)s material can be adjusted, causing the invention to have broad application in such fields as engineering plastics, thermoplastic elastomers, tissue engineering, and controlled release.

Disclosed in the present invention is poly(ester amide)s and method for preparing thermoplastic poly(ester amide)s therefor. The poly(ester amide)s are prepared using diamine or alkamine as initiator, with diacid and dialcohol-based cyclicester as the monomer, in the catalyst, and by cascade polycondensation-coupling ring-opening polymerization. The obtained poly(ester amide)s have good mechanical properties, solvent resistance and thermal stability. It effectively solves the deficiencies in the current poly(ester amide)s, such as low crystallization temperature and poor heat resistance of polyester parts, and low modulus and rigidity from polyamides part. For aliphatic poly(ester amide)s, they are biodegradable. By means of altering such factors as the ratio of ester bonds and amide bonds and polymer molecular weight and distribution, the performance of the poly(ester amide)s material can be adjusted, causing the invention to have broad application in such fields as engineering plastics, thermoplastic elastomers, tissue engineering, and controlled release.

A continuous polymerization method for nylon. Polymerization starting materials comprise, in parts by mass, 5-60 parts of polymerization monomer dibasic acid and/or dibasic acid ester, 3-50 parts of diamine, and 10-90 parts of reactive dispersion medium polyamide. Polymerization steps comprise: continuously adding the polymerization starting materials into a material mixing device in proportion, so that the raw materials are mixed and reacted in the material mixing device to form a continuously conveyed melt, and reacting the evenly dispersed melt in a subsequent polymerization device until nylon is polymerized to reach a required molecular weight. The method is an efficient and environment-friendly polymerization method for nylon.

A continuous polymerization method for nylon. Polymerization starting materials comprise, in parts by mass, 5-60 parts of polymerization monomer dibasic acid and/or dibasic acid ester, 3-50 parts of diamine, and 10-90 parts of reactive dispersion medium polyamide. Polymerization steps comprise: continuously adding the polymerization starting materials into a material mixing device in proportion, so that the raw materials are mixed and reacted in the material mixing device to form a continuously conveyed melt, and reacting the evenly dispersed melt in a subsequent polymerization device until nylon is polymerized to reach a required molecular weight. The method is an efficient and environment-friendly polymerization method for nylon.

Disclosed herein are processes of making furan-based polyamides using solvent-free melt condensation of a diamine and an ester derivative of 2,5-furandicarboxylic acid with a C.sub.2 to C.sub.12 aliphatic diol or a polyol. The processes comprise a) forming a reaction mixture by mixing one or more diamines, a diester comprising an ester derivative of 2,5-furandicarboxylic acid with a C.sub.2 to C.sub.12 aliphatic diol or a polyol, and a catalyst, such that the diamine is present in an excess amount of at least 1 mol % with respect to the diester amount; and b) melt polycondensing the reaction mixture in the absence of a solvent at a temperature in the range of 60° C. to a maximum temperature of 250° C. under an inert atmosphere, while removing alkyl alcohol to form a furan-based polyamide, wherein the one or more diamines comprises an aliphatic diamine, an aromatic diamine, or an alkylaromatic diamine.

Polyamide and amidoamine curing agents comprising a selectively modified amine. The selectively modified amine is formed by a substitution reaction between a polyamine and an epoxide, resulting in a multifunctional amine having a hydroxyl substituent. The curing agents are used to form epoxy resins having improved properties when cured.

Polyamide and amidoamine curing agents comprising a selectively modified amine. The selectively modified amine is formed by a substitution reaction between a polyamine and an epoxide, resulting in a multifunctional amine having a hydroxyl substituent. The curing agents are used to form epoxy resins having improved properties when cured.

Disclosed in the present invention is a polyamide 5X industrial yarn. The polyamide 5X industrial yarn has a heat-resistant break strength retention rate of 90% or more after being treated at 180° C. for 4 hrs; a heat-resistant break strength retention rate of 90% or more after being treated at 230° C. for 30 mins; and a dry heat shrinkage of 8.0% or less. The polyamide 5X industrial yarn is widely used in the fields of sewing threads, tire cords, air bag yarns, release cloth, krama, canvas, safety belts, ropes, fishing nets, industrial filter cloth, conveyor belts, parachutes, tents, bags and suitcases.

Disclosed in the present invention is a polyamide 5X industrial yarn. The polyamide 5X industrial yarn has a heat-resistant break strength retention rate of 90% or more after being treated at 180° C. for 4 hrs; a heat-resistant break strength retention rate of 90% or more after being treated at 230° C. for 30 mins; and a dry heat shrinkage of 8.0% or less. The polyamide 5X industrial yarn is widely used in the fields of sewing threads, tire cords, air bag yarns, release cloth, krama, canvas, safety belts, ropes, fishing nets, industrial filter cloth, conveyor belts, parachutes, tents, bags and suitcases.