Thermoplastic biodegradable resins and a process of preparation thereof
AssigneeSunkyong Industries Co., Ltd.
InventorsHyo Y. Kim, Ki H. Hwang, Hoon Chae, Soo I. Sho, Jung N. Jun
Life of this patent
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Abstract
A thermoplastic biodegradable resin having a number average molecular weight of 25,000-45,000, which is prepared by polycondensing one or a plurality of dicarboxylic acids represented by formula (I) with one or a plurality of diols represented by formula (II): ROOC--(--CH.sub.2 --).sub.n --COOR (I) HO--(--CH.sub.2 --).sub.m --OH (II) wherein R and R' are both hydrogen or are both methyl, n is 2 to 8 and m is 2 to 6.
Claims9
A thermoplastic biodegradable aliphatic polyester consisting essentially of an aliphatic polyester having a number average molecular weight of 25,000-45,000, which is prepared by polycondensing one or a plurality of aliphatic dicarboxylic acids presented by formula (I) with one or a plurality of aliphatic diols represented by formula (II):
- ROOC--(--CH.sub.2 --).sub.n --COOR (I)
- HO--(--CH.sub.2 --).sub.m --OH (II)
- wherein R and R' are both hydrogen or are both methyl, n is 2 to 8 and m is 2 to 6.
A method of preparing a biodegradable thermoplastic aliphatic polyester comprising reacting an aliphatic dicarboxylic acid of 4 to 10 carbon atoms and an aliphatic diol of 2 to 6 carbon atoms in a first stage of an esterification or an ester exchange reaction and a final stage of a polycondensation reaction, wherein, from 0.005 to 2 weight % of tetrabutyl titanate or a mixture of tetrabutyl titanate and at least one catalyst selected from the group consisting of calcium acetate, zinc acetate, dibutyltinoxide and tetrapropyl titanate is present in the first stage of esterification or ester exchange reaction and wherein from 0.2 to 1.5 weight % of dibutyltinoxide or dibutyltinoxide and at least one other catalyst selected from the group consisting of tetrabutyl titanate, tetrapropyl titanate, calcium acetate and tetraisopropyl titanates, 0.1 to 0.8 weight % of a stabilizer and less than 0.015 weight % of an adjusting agent are added to the reaction at the end of the esterification or ester exchange reaction or at the start of polycondensation.
Dependencies are inferred from the claim text.