Semiaromatic polyamide, semiaromatic polyamide resin composition, and molded article

Abstract

The purpose of the present invention is to provide: a semiaromatic polyamide which has excellent heat resistance, chemical resistance and mechanical characteristics, while exhibiting moldability that is suitable for various component materials for automobiles and the like; and a molded article of this semiaromatic polyamide. A semiaromatic polyamide (I) of the present invention contains 35-50% by mole of a structural unit derived from terephthalic acid [A], 25-40% by mole of a structural unit derived from isophthalic acid [B], 15-35% by mole of a structural unit derived from an aliphatic dicarboxylic acid [C] (provided that the total of [A], [B] and [C] is 100% by mole), and a structural unit derived from an aliphatic diamine [D] having 4-12 carbon atoms. The molar ratio ([A] / [B]) is from 65 / 35 to 50 / 50, and the molar ratio ([C] / [B]) is from 30 / 70 to 50 / 50. The melting enthalpy (∆H) of the semiaromatic polyamide (I) as determined by differential scanning calorimetry (DSC) is 20-40 mJ / mg, and the limiting viscosity [η] of the semiaromatic polyamide (I) is 0.7-1.6 dl / g.

Description

Technical field [0001] The present invention relates to semi-aromatic polyamides, semi-aromatic polyamide resin compositions and molded products. Background technique [0002] Polyamides represented by nylon 6, nylon 66, etc. are excellent in molding processability, mechanical properties, and chemical resistance, so they are widely used as materials for various parts such as clothing, industrial materials, automobiles, electrical / electronics, or industrial use. . [0003] However, in recent years, the mechanical properties, fuel barrier properties, and coolant resistance, and other functions required for polyamide molded articles have been further improved due to the demand for metal replacement for the purpose of reducing the weight of parts. More specifically, the current situation is that the heat resistance, dimensional stability, mechanical properties, chemical resistance, etc. of the conventional nylon 6 and nylon 66 are insufficient and cannot be used in automobile fuel pip...

AI Technical Summary

Problems solved by technology

However, in this method, it is difficult to control the reaction of the polyamide resin and the reactive modifying material, so local thickening occurs when the resin stays, which sometimes causes a change in the thickness of the molded product

In addition, cross-linked gel may be formed and the appearance of molded products may deteriorate

In addition, in order to increase the melt viscosity of polyamide itself, a long-chain methylene group is introduced into the main chain, resulting in a significant decrease in the mechanical strength of the molded product, which is also a big problem.

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