Patent US5874040A successfully refreshed from Google Patents.
US5874040A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Processing of polyesters
Assignee: CJ CheilJedang Corp
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Filing: 1997-07-14
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Granted: 1999-02-23
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Expires: 2017-07-14
Abstract
Abstract Process for improving mechanical properties of an aged polyester composition consisting essentially of copolymer of hydroxybutyrate units and hydroxyvalerate units which comprises heating the polyester at a temperature whereby (i) the polyester is restored to its original non-aged properties, and (ii) subsequent ageing of the polyester is retarded as indicated by substantial improvement of at least one measurement indicative of ageing compared to non heat treated polyester of the same age. The invention includes the polyester composition and shaped articles which have been subjected to the process and in which ageing is retarded.
Inventors
- 👤 John Jamieson Liggat
- 👤 Gregory O'Brien
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-23 12:07
CPC Classifications
C; C08; C08G; C08G63/00; C08G63/88; C08G63/02; C08G63/06
Claims Analysis
Total Claims: 10
Claim 1
Independent Claim
160 words
Process for producing, by extrusion, production of film, injection molding, thermoforming, an embrittlement-resistant shaped article at least partly made of a copolymer of polyhydroxyalkanoate (PHA), characterised by the succession of steps: (a) producing as said PHA a plasticizer-free microbiologically produced polyester in the (R)-3-hydroxy form having units of formula --O--C m H n --CO-- where n is 2 m and m is 4 to the extent of 4-20 mol %, the balance being m=3 units; (b) shaping said PHA; (c) ageing the resulting shape for the equivalent of at least 24 hours at 20° C. until a deterioration by more than 50% has taken place in ductility as measured by percentage elongation to break and/or IZOD impact strength; and (d) heating the so-aged shape at a temperature in the range 100° to 140° C. until its ductility as so measured has increased to at least 50% of its value before said ageing and has substantially stabilized at that increased level.
Claim 2
Dependent Claim
160 words
Process for producing, by extrusion, production of film, injection molding, thermoforming, an embrittlement-resistant shaped article at least partly made of a copolymer of polyhydroxyalkanoate (PHA), characterised by the succession of steps: (a) producing as said PHA a plasticizer-free microbiologically produced polyester in the (R)-3-hydroxy form having units of formula --O--C m H n --CO-- where n is 2 m and m is 4 to the extent of 4-20 mol %, the balance being m=3 units; (b) shaping said PHA; (c) ageing the resulting shape for the equivalent of at least 24 hours at 20° C. until a deterioration by more than 50% has taken place in ductility as measured by percentage elongation to break and/or IZOD impact strength; and (d) heating the so-aged shape at a temperature in the range 100° to 140° C. until its ductility as so measured has increased to at least 50% of its value before said ageing and has substantially stabilized at that increased level.
Claim 3
Dependent Claim
109 words
Process for improving and stabilising the mechanical properties of a shaped article at least partly made of plasticiser-free microbiologically produced polyester of a copolymer in the (R)-3-hydroxy form having units of formula --O--C m H n --CO-- where n is 2 m and m is 4 to the extent of 4-20 mol %, the balance being m=3 units, in which ageing has occurred resulting in deterioration of ductility as measured by percentage elongation to break and/or IZOD impact strength; and which comprises heating it at a temperature in the range 100°-140° C. until its ductility as so measured has substantially increased and has substantially stabilised at that increased level.
Claim 4
Dependent Claim
109 words
Process for improving and stabilising the mechanical properties of a shaped article at least partly made of plasticiser-free microbiologically produced polyester of a copolymer in the (R)-3-hydroxy form having units of formula --O--C m H n --CO-- where n is 2 m and m is 4 to the extent of 4-20 mol %, the balance being m=3 units, in which ageing has occurred resulting in deterioration of ductility as measured by percentage elongation to break and/or IZOD impact strength; and which comprises heating it at a temperature in the range 100°-140° C. until its ductility as so measured has substantially increased and has substantially stabilised at that increased level.
Claim 5
Dependent Claim
23 words
Process according to claim 1 or claim 2 in which heating is for a period in the range 5 sec to 20 h.
Claim 6
Dependent Claim
14 words
Process according to claim 3 in which transfer of heat is by infra-red radiation.
Claim 7
Dependent Claim
63 words
A shaped article at least partly made of plasticiser-free microbiologically produced polyester of a copolymer in the (R)-3-hydroxy form having units of the formula --O--C m H n --CO-- where n is 2 m and m is 4 to the extent of 4-20 mol %, the balance being m=3 units: characterised by substantial stability of percentage elongation to break and/or IZOD impact resistance.
Claim 8
Dependent Claim
63 words
A shaped article at least partly made of plasticiser-free microbiologically produced polyester of a copolymer in the (R)-3-hydroxy form having units of the formula --O--C m H n --CO-- where n is 2 m and m is 4 to the extent of 4-20 mol %, the balance being m=3 units: characterised by substantial stability of percentage elongation to break and/or IZOD impact resistance.
Claim 9
Dependent Claim
22 words
A shaped article according to claim 5 wherein the produced polyester consists essentially of a copolymer of hydroxybutyrate units and hydroxyvalerate units.
Claim 10
Dependent Claim
24 words
A process according to claim 1 or claim 2 wherein the produced polyester consists essentially of a copolymer of hydroxybutyrate units and hydroxyvalerate units.
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) | 2002-02-22 | 2002-08-24 | 2003-02-23 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 2006-02-22 | 2006-08-24 | 2007-02-23 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2010-02-22 | 2010-08-24 | 2011-02-23 | $7700.00 | Window Closed / Lapsed |