Starch ester
AssigneeJapan Corn Starch Co., Ltd.
InventorHideyuki Tanaka
Life of this patent
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Abstract
The present invention relates to a starch ester having short- and long-chain acyl groups wherein hydrogens in reactive hydroxyl groups in the same starch molecule have been replaced by C2-4 short-chain acyl groups and C6-18 long-chain acyl groups. The degree of substitution by the short- and long-chain acyl groups are regulated so as to make the starch ester thermo-plasticized and moldable even in the absence of a plasticizer. Accordingly, the starch ester of the present invention can be used as a biodegradable thermoplastic plastic material which can be thermo-plasticized in the absence of a plasticizer.
Claims7
A polymer alloy which comprises a starch ester incorporated with a biodegradable resin, wherein hydrogens in reactive hydroxyl groups in the same starch molecule have been replaced by C2-4 acyl groups (referred to hereinafter as “short-chain acyl group”) and C6-18 acyl groups (referred to hereinafter as “long-chain acyl group”), the degree of substitution by the short- and long-chain acyl groups are regulated so as to make the polymer alloy thermo-plasticized and moldable even in the absence of a plasticizer;
- and wherein the glass transition point of the starch ester by differential thermal analysis (JIS K 7121:
- referred to hereinafter as the “glass transition point”) is 130° C. or less.
A plastic processed article which has been molded and processed or modified as a whole or partially with a polymer alloy, wherein the polymer alloy comprises a starch ester incorporated with a biodegradable resin, wherein hydrogens in reactive hydroxyl groups in the same starch molecule have been replaced by C2-4 acyl groups (referred to hereinafter as “short-chain acyl group”) and C6-18 acyl groups (referred to hereinafter as “long-chain acyl group”), the degree of substitution by the short- and long-chain acyl groups are regulated so as to make the polymer alloy thermo-plasticized and moldable even in the absence of a plasticizer, and wherein the plastic processed article is an injection-molded article showing a degree of water absorption (after immersion in tap water at 23° C. for 24 hours) of 0.5% or less and an Izod impact strength of 1.8 kgf·cm/cm or more.
Dependencies are inferred from the claim text.