US5238968A
Expired / Lapsed
US
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Process for preparing a degradable high polymer network
Assignee: Mitsui Chemicals Inc
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Filing: 1993-01-15
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Granted: 1993-08-24
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Expires: 2013-01-15
Abstract
Abstract A degradable polymer network obtained by adding from 0.2 to 10 parts by weight of a foaming agent to 100 parts by weight of a polylactic acid-base resin composition comprising from 80 to 100% by weight of polylactic acid or a lactic acid-hydroxycarboxylic acid copolymer and from 0 to 20% by weight of a plasticizer, conducting melt-foaming extrusion of resulting mixture, and opening the foam cells in the extrudate. The high polymer network is characterized in suitable flexibility and hydrolyzability and thus useful as a material for absorbing of oils and body fluids, screens for sunlight, heat-insulating materials, filter media and packaging materials; and does not accumulate as industrial wastes because of hydrolyzability in the natural environment, even though abandoned after use.
Inventors
- 👤 Kenji Morita
- 👤 Kohichi Uchiki
- 👤 Hosei Shinoda
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-27 22:03
CPC Classifications
B; B29; B29C; B29C44/00; B29C44/34; B29C44/56; B29C44/5627; B29C44/5672; C; C08; C08J; C08J9/00; C08J9/04; C08J9/06; C08J9/12; C08J2300/00; C08J2300/16; C08J2367/00; C08J2367/04
Claims Analysis
Total Claims: 21
Claim 1
Independent Claim
93 words
A process for preparing a degradable high polymer network having mesh structure comprising fibrous branches of the high polymer and comprising adding from 0.2 to 10 parts by weight of a foaming agent to 100 parts by weight of a polylactic acid-base resin composition comprising from 80 to 100% by weight of polylactic acid or a lactic acid-hydroxycarboxylic acid copolymer and from 0 to 20% by weight of a plasticizer, conducting melt-foaming extrusion of the resulting mixture, stretching the delivered, molten-foam with simultaneous cooling and thereby opening the cells generated in the foam.
Claim 2
Dependent Claim
93 words
A process for preparing a degradable high polymer network having mesh structure comprising fibrous branches of the high polymer and comprising adding from 0.2 to 10 parts by weight of a foaming agent to 100 parts by weight of a polylactic acid-base resin composition comprising from 80 to 100% by weight of polylactic acid or a lactic acid-hydroxycarboxylic acid copolymer and from 0 to 20% by weight of a plasticizer, conducting melt-foaming extrusion of the resulting mixture, stretching the delivered, molten-foam with simultaneous cooling and thereby opening the cells generated in the foam.
Claim 3
Dependent Claim
28 words
The process for preparing a degradable high polymer network of claim 1 wherein the polylactic acid essentially consists of an L-lactic acid unit of a D-lactic acid unit.
Claim 4
Dependent Claim
41 words
The process for preparing a degradable high polymer network of claim 1 wherein the polylactic acid comprises from 85 to less than 100% by mole of an L-lactic acid unit and less than 15% by mole of a D-lactic acid unit.
Claim 5
Dependent Claim
40 words
The process for preparing a degradable high polymer network of claim 1 wherein the polylactic acid comprises from 85 to less than 100% by mole of a D-lactic acid unit and less-than 15% by mole of an L-lactic acid unit.
Claim 6
Dependent Claim
43 words
The process for preparing a degradable high polymer network of claim 1 wherein the lactic acid-hydroxycarboxylic acid copolymer comprises from 85 to less than 100% by mole of an L-lactic acid unit and less than 15% by mole of a glycolic acid unit.
Claim 7
Dependent Claim
43 words
The process for preparing a degradable high polymer network of claim 1 wherein the lactic acid-hydroxycarboxylic acid copolymer comprises from 85 to less than 100% by mole of a D-lactic acid unit and less than 15% by mole of a glycolic acid unit.
Claim 8
Dependent Claim
34 words
The process for preparing a degradable high polymer network of claim 6 wherein the plasticizer is lactic acid, a lactic acid oligomer or the plasticizer is lactic acid, a lactic acid oligomer or lactide.
Claim 9
Dependent Claim
20 words
The process for preparing a degradable high polymer network of claim 6 wherein the foaming agent is azodicarboxylic acid amide.
Claim 10
Dependent Claim
30 words
The process for preparing a degradable high polymer network of claim 1 wherein the temperature for conducting the melt-foaming extrusion is in the range of from 100° to 270° C.
Claim 11
Dependent Claim
42 words
The process for preparing a degradable high polymer network of claim 1 wherein cooling of the molten foam is carried out by using a cooling gas in an amount of from 1 to 15 m 3 per square meter of the network.
Claim 12
Dependent Claim
34 words
The process for preparing a degradable high polymer network of claim 1 wherein the plasticizer is lactic acid, a lactic acid oligomer or the plasticizer is lactic acid, a lactic acid oligomer or lactide.
Claim 13
Dependent Claim
34 words
The process for preparing a degradable high polymer network of claim 2 wherein the plasticizer is lactic acid, a lactic acid oligomer or the plasticizer is lactic acid, a lactic acid oligomer or lactide.
Claim 14
Dependent Claim
34 words
The process for preparing a degradable high polymer network of claim 3 wherein the plasticizer is lactic acid, a lactic acid oligomer or the plasticizer is lactic acid, a lactic acid oligomer or lactide.
Claim 15
Dependent Claim
34 words
The process for preparing a degradable high polymer network of claim 4 wherein the plasticizer is lactic acid, a lactic acid oligomer or the plasticizer is lactic acid, a lactic acid oligomer or lactide.
Claim 16
Dependent Claim
34 words
The process for preparing a degradable high polymer network of claim 5 wherein the plasticizer is lactic acid, a lactic acid oligomer or the plasticizer is lactic acid, a lactic acid oligomer or lactide.
Claim 17
Dependent Claim
20 words
The process for preparing a degradable high polymer network of claim 1 wherein the foaming agent is azodicarboxylic acid amide.
Claim 18
Dependent Claim
20 words
The process for preparing a degradable high polymer network of claim 2 wherein the foaming agent is azodicarboxylic acid amide.
Claim 19
Dependent Claim
20 words
The process for preparing a degradable high polymer network of claim 3 wherein the foaming agent is azodicarboxylic acid amide.
Claim 20
Dependent Claim
20 words
The process for preparing a degradable high polymer network of claim 4 wherein the foaming agent is azodicarboxylic acid amide.
Claim 21
Dependent Claim
20 words
The process for preparing a degradable high polymer network of claim 5 wherein the foaming agent is azodicarboxylic acid amide.
References Cited (Backward Citations)
US1995970A
Cited
JPS5147170A
Cited
US4181983A
Cited
EP0171693A2
Cited
US4702917A
Cited
US4719246A
Cited
US4766182A
Cited
WO1992001737A1
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1996-08-23 | 1997-02-22 | 1997-08-24 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 2000-08-23 | 2001-02-22 | 2001-08-24 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2004-08-23 | 2005-02-22 | 2005-08-24 | $7700.00 | Window Closed / Lapsed |