Patent US3632187A successfully refreshed from Google Patents.
Patent US4859763A successfully refreshed from Google Patents.
US4859763A
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Preparation process of dl-lactic acid-glycolic acid-copolymer
Assignee: Mitsui Chemicals Inc
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Filing: 1988-07-08
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Granted: 1989-08-22
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Expires: 2008-07-08
Abstract
Abstract A process for copolymerizing lactide and glycolide by using a specific amount of stannous octoate as a catalyst in the presence of a polymerization regulator at temperature of 200°-230° C. to prepare dl-lactic acid-glycolic acid-copolymers which contain 50-60 mol % of a dl-lactic acid unit and 40-50 mol % of a glycolic acid unit and have inherent viscosity of 0.4-0.6 in chloroform.
Inventors
- 👤 Hiroshi Takayanagi
- 👤 Tadashi Kobayashi
- 👤 Takayoshi Masuda
- 👤 Hosei Shinoda
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-08 07:14
CPC Classifications
A; A61; A61K; A61K9/00; A61K9/20; A61K9/2004; A61K9/2022; A61K9/2031; A61K9/204; C; C08; C08G; C08G63/00; C08G63/02; C08G63/06; C08G63/08; C08G63/78; C08G63/82; C08G63/823
Claims Analysis
Total Claims: 4
Claim 1
Independent Claim
89 words
In a process for the copolymerization of a lactide and a glycolide to prepare a dl-lactic acid-glycolic acid-copolymer containing 50-60 mol % of a lactic acid unit and 40-50 mol % of a glycolic acid unit and having an inherent viscosity of 0.4-0.6 in chloroform, the improvement which comprises conducting the copolymerization in the presence of a polymerization regulator at a temperature of 200°-230° C. by using stannous octoate as a catalyst in an amount of 0.005-0.015 wt. % based on the sum of the lactide and the glycolide.
Claim 2
Dependent Claim
89 words
In a process for the copolymerization of a lactide and a glycolide to prepare a dl-lactic acid-glycolic acid-copolymer containing 50-60 mol % of a lactic acid unit and 40-50 mol % of a glycolic acid unit and having an inherent viscosity of 0.4-0.6 in chloroform, the improvement which comprises conducting the copolymerization in the presence of a polymerization regulator at a temperature of 200°-230° C. by using stannous octoate as a catalyst in an amount of 0.005-0.015 wt. % based on the sum of the lactide and the glycolide.
Claim 3
Dependent Claim
15 words
A process of claim 1 wherein said polymerization regulator is a α-hydroxy lower fatty acid.
Claim 4
Dependent Claim
42 words
A process for the preparation of the dl-lactic acid-glycolic acid-copolymer of claim 2 wherein said α-hydroxy lower fatty acid is dl-lactic acid containing water and the amount therefor is 0.25-0.50 wt. % based on the sum of the lactide and the glycolide.
References Cited (Backward Citations)
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1992-08-21 | 1993-02-20 | 1993-08-22 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1996-08-21 | 1997-02-20 | 1997-08-22 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2000-08-21 | 2001-02-20 | 2001-08-22 | $7700.00 | Window Closed / Lapsed |