Aromatic polyester resin moldings and process for production thereof

Abstract

An aromatic polyester resin molded product, including: a matrix of 99 - 70 wt. parts of an aromatic polyester resin, and a disperse phase of 1 - 30 wt. parts (providing a total of 100 wt. parts together with the aromatic polyester resin) of a polyglycolic acid resin present in the matrix, wherein the molded product exhibits an oxygen permeability in its thickness direction which is in a range of 55 - 85 % of a minimum gas permeability P 0 determined by formula (1) below (Nielsen's theoretical formula): P0=P1*phi1 / (1+ (L / 2)*phi2)...(1), wherein L denotes a longer axis of the polyglycolic acid resin disperse phase; W denotes a shorter axis (thickness) of the polyglycolic acid resin disperse phase; P1 denotes an oxygen permeability of the aromatic polyester resin in an oriented and crystallized state; phi1 denotes a volumetric fraction of the aromatic polyester resin; and phi2 denotes a volumetric fraction of the polyglycolic acid resin. The molded product can be produced by subjecting a primarily molded product of a prescribed composition to stretching and heat-treatment. As a result, the aromatic polyester resin molded product formed by adding a relatively small amount of polyglycolic acid resin is provided with an improved gas-barrier property while utilizing the effect of the added polyglycolic acid resin to the utmost.

Description

technical field [0001] The present invention relates to a further improvement of the gas barrier properties of an aromatic polyester-based resin molded article whose gas barrier properties have been improved by compounding a polyglycolic acid resin, and more specifically, to an aromatic resin having such improved gas barrier properties. A molded article of a family polyester resin and a method for producing the same. Background technique [0002] Aromatic polyester resins represented by polyethylene terephthalate are excellent in moldability, mechanical properties, transparency, etc., and are widely used as packaging materials for various food and beverage containers. However, as a packaging material for foods that require long-term storage, aromatic polyester resins have insufficient gas barrier properties, and it is difficult to avoid deterioration of the contents due to oxygen permeation during long-term storage. [0003] On the other hand, it is known that polyglycolic ...

AI Technical Summary

Problems solved by technology

[0006] However, in any of the aromatic polyester resin molded articles obtained from the above-mentioned Patent Documents 2 and 3, when the dispersed phase of the polyglycolic acid resin is used as the gas-barrier dispersed phase, the above-mentioned Nielsen theoretical formula can not be obtained. The effect of improving the gas barrier property (the effect of reducing the air permeability)

Images