Degradable polymer and preparation process of the same

• US 5,914,381 A
• Filed: 09/08/1997
• Issued: 06/22/1999
• Est. Priority Date: 09/12/1996
• Status: Expired due to Term

• Current Assignee: Mitsui Chemicals Incorporated (Mitsui Chemicals)
• Original Assignee: Mitsui Chemicals Incorporated (Mitsui Chemicals)
• Inventors: Higuchi, Chojiro, Terado, Yuji, Suizu, Hiroshi, Ajioka, Masanobu
• Primary Examiner(s): Nutter, Nathan M.
• Application Number:
  US08/925,133
• Time in Patent Office: 652 Days
• Field of Search: 527/300, 527/311, 527/325, 525/54.2, 525/54.21, 525/54.24, 525/54.3, 525/54.31
• US Class Current: 527/300
• CPC Class Codes: C08G 63/60 derived from the reaction of a mixture of hydroxy carboxylic acids, polycarboxylic acids and polyhydroxy compounds

Abstract

A degradable polymer and a process for preparing the degradable polymer which has a structure resulting from combination of a star-shaped polymer comprising a polyfunctional base compound of polycarboxylic acid having three or more carboxyl groups and/or anhydride of the same or aliphatic polyhydric alcohol having three or more hydroxyl groups and a unit of aliphatic hydroxycarboxylic acid, with aliphatic polyhydric alcohol having two or more hydroxyl groups or polycarboxylic acid having two or more carboxyl groups or anhydrides of the same. The degradable polymer leads to remarkably low coloration as compared with a polymer comprising polysaccharide as a polyfunctional base compound, has high melt tension as compared to common aliphatic polyester is excellent in processability on various molding methods, foam molding and blow molding in particular, and high transparency.

Claims

1. A process for preparing a degradable polymer comprising reacting, by dehydration condensation in the presence of a catalyst,

component (A):

aliphatic hydroxycarboxylic acid,

component (B);

only one material selected from the group consisting of;

(b-1) polycarboxylic acid having three or more carboxyl groups and/or anhydride thereof,

and (b-3) aliphatic polyhydric alcohol having three or more hydroxyl groups with the proviso that the aliphatic polyhydric alcohol having three or more hydroxyl groups is not a polysaccharide, and

component (C);

only one material which can conduct an esterification reaction with compound (B) and is selected from the group consisting of

(c-1) polycarboxylic acid having two or more carboxyl groups and/or anhydride thereof, and

(c-3) aliphatic polyhydric alcohol having two or more hydroxyl groups wherein the amount of component (B) corresponds to 0.005-10% by weight for the theoretical amount of the polymer resulting from complete hompolycondensation of component (A) and an equivalent ratio of component (B) to component (C) is 100;

90-110.

2. The process for preparing a degradable polymer according to claim 1, wherein component (B) is (b-1) polycarboxylic acid having three or more carboxyl groups and/or anhydride there of and component (C) is (c-3) aliphatic polyhydric alcohol having two or more hydroxyl groups.

3. The process for preparing a degradable polymer according to claim 1, wherein component (B) is (b-3) aliphatic polyhydric alcohol having three or more hydroxyl groups and component (C) is (c-1) polycarboxylic acid having two or more carboxyl groups and/or anhydride thereof.

4. The process for preparing a degradable polymer according to claim 1, wherein (b-1) polycarboxylic acid having three or more carboxyl groups and/or anhydride thereof is a linear compound.

5. The process for preparing a degradable polymer according to claim 4, wherein (b-1) polycarboxylic acid having three or more carboxyl groups is butane-1,2,3,4-tetracarboxylic acid and/or anhydride thereof.

6. The process for preparing a degradable polymer according to claim 1, wherein (b-3) aliphatic polyhydric alcohol having three or more hydroxyl group is one or more compound selected from the group consisting of glycerol, pentaerythritol, dipentaerythritol, trimethylolethane, trimethylolpropane and inositol.

7. The process for preparing a degradable polymer according to claim 1, wherein the dehydration condensation is carried out in an organic solvent substantially in the absence of water.

8. The process for preparing a degradable polymer according to claim 7, wherein a portion or all of the organic solvent in the reaction system is removed and additional organic solvent having a water content less than or equal to the water content dissolved in the removed organic solvent is charged.

9. The process for preparing a degradable polymer according to claim 8, wherein the additional organic solvent has a water content of 50 ppm or less.

10. The process for preparing a degradable polymer according to claim 8, wherein the the removed organic solvent is treated by bringing the removed organic solvent into contact with a drying agent.

13. The degradable polymer obtained by the process according to claim 1.

14. The degradable polymer according to claim 13, which has a melt tension of 0.7 g or more at temperature indicating a melt-flow index of 10 g/10 minutes.

15. A foam, molded article, container, sheet or film comprising the degradable polymer according to claim 13.

11. A process for preparing a degradable polymer comprising reacting, in the presence of a catalyst, only a), b) and c) wherein a) is a cyclic dimer and/or lactone of aliphatic hydroxycarboxylic acid, b) is an aliphatic polyhydric alcohol having three or more hydroxyl groups with the proviso that the aliphatic polyhydric alcohol is not a polysaccharide, and c) is a polycarboxylic acid having two or more carboxyl groups and/or anhydride of the same.

12. The process for preparing a degradable polymer according to claim 11, wherein an amount of aliphatic polyhydric alcohol having three or more hydroxyl group corresponds to 0.005-1% by weight for the theoretical amount of the polymer resulting from complete homopolymerization of cyclic dimer and/or lactone and an equivalent ratio of aliphatic polyhydric alcohol having three or more hydroxyl group to polycarboxylic acid having two or more carboxyl group and/or anhydride of the same is 100:

90-110.

16. A degradable polymer having a structure resulting from combination of a star-shaped polymer comprising only a polyfunctional base compound of polycarboxylic acid having three or more carboxyl groups and/or anhydride of the same and a unit of aliphatic hydroxycarboxylic acid, with aliphatic polyhydric alcohol having two or more hydroxyl groups with the proviso that the aliphatic polyhydric alcohol is not a polysaccharide.

17. A degradable polymer having a structure resulting from combination of a star-shaped polymer comprising only a polyfunctional base compound of polyhydric alcohol having three or more hydroxyl groups with the proviso that the aliphatic polyhydric alcohol is not a polysaccharide and a unit of aliphatic hydroxycarboxylic acid, with polycarboxylic acid having two or more carboxyl groups and/or anhydride of the same.

18. A process for preparing a degradable polymer comprising reacting by dehydrating condensation in the presence of a catalyst, L-lactic acid, pentacrythritol and succinic acid.