Patent DE2218901A1 successfully refreshed from Google Patents.
US5917002A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Poly(3-hydroxybutanoic acid) film
Assignee: Akebono Research and Development Centre Ltd
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Filing: 1997-12-18
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Granted: 1999-06-29
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Expires: 2017-12-18
Abstract
Abstract Poly(3-hydroxybutanoic acid) having a number average molecular weight of not less than 500,000 is oriented at a draw ratio of 2-fold or more to reproducibly obtain a film made of poly(3-hydroxybutanoic acid) having biodegradability and biocompatibility as well as sufficient strength and flexibility (for example, tensile strength of not less than 30 MPa and elongation to break of not less than 15%).
Inventors
- 👤 Yoshiharu Doi
- 👤 Tadahisa Iwata
- 👤 Satoshi Kusaka
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-23 04:51
CPC Classifications
C; C08; C08J; C08J5/00; C08J5/18; C12; C12P; C12P7/00; C12P7/62; C12P7/625; C08J2367/00; C08J2367/04
Claims Analysis
Total Claims: 8
Claim 1
Independent Claim
69 words
A method of producing a poly(3-hydroxybutanoic acid) film, which is biodegradable and which has a tensile strength of not less than 30 MPa and a breaking extension of not less than 15%, comprising the steps of obtaining a non-stretched film made of poly(3-hydroxybutanoic acid) homopolymer having a number average molecular weight of not less than 500,000; and stretching the non-stretched film at a draw ratio of two-fold or more.
Claim 2
Independent Claim
69 words
A method of producing a poly(3-hydroxybutanoic acid) film, which is biodegradable and which has a tensile strength of not less than 30 MPa and a breaking extension of not less than 15%, comprising the steps of obtaining a non-stretched film made of poly(3-hydroxybutanoic acid) homopolymer having a number average molecular weight of not less than 500,000; and stretching the non-stretched film at a draw ratio of two-fold or more.
Claim 3
Dependent Claim
22 words
The method as claimed in claim 1, wherein said orienting is carried out at a temperature ranging from 155 to 180° C.
Claim 4
Dependent Claim
48 words
The method as claimed in claim 1, wherein said poly(3-hydroxybutanoic acid) having a number average molecular weight of not less than 500,000 is obtained by cultivating a microorganism transformed with a recombinant DNA containing a poly(3-hydroxybutanoic acid) synthesis gene and recovering poly(3-hydroxybutanoic acid) produced in the microbial cells.
Claim 5
Independent Claim
29 words
The method as claimed in claims 1, further comprising the step of heating the oriented film obtained from the orienting step at a temperature of 60 to 170° C.
Claim 6
Dependent Claim
40 words
A biodegradable stretched film made of poly(3-hydroxybutanoic acid) homopolymer haing a number average molecular weight of not less than 500,000, which has a tensile strength of not less than 30 MPa and a breaking extension of not less than 15%.
Claim 7
Dependent Claim
40 words
A biodegradable stretched film made of poly(3-hydroxybutanoic acid) homopolymer haing a number average molecular weight of not less than 500,000, which has a tensile strength of not less than 30 MPa and a breaking extension of not less than 15%.
Claim 8
Dependent Claim
22 words
The film as claimed in claim 5, which is a crystalline film in which said poly(3-hydroxybutanoic acid) is oriented in one direction.
References Cited (Backward Citations)
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USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 2002-06-28 | 2002-12-28 | 2003-06-29 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 2006-06-28 | 2006-12-28 | 2007-06-29 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2010-06-28 | 2010-12-28 | 2011-06-29 | $7700.00 | Window Closed / Lapsed |