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US4294935A
Expired / Lapsed
US
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Method of producing ethylene-vinyl alcohol copolymer film
Assignee: Kuraray Co Ltd
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Filing: 1979-12-19
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Granted: 1981-10-13
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Expires: 1999-12-19
Abstract
Abstract An ethylene-vinylalcohol copolymer film is prepared by biaxially or multiaxially stretching a nonstretched ethylene-vinylalcohol polymer film having a moisture content of not more than 3.5%, said ethylenevinyl alcohol copolymer having an ethylene content of 20 to 55 mole % and a saponification degree of not less than 96 mole % and said stretching being conducted within a temperature range of 50 DEG to 150 DEG C. to such an extent that the film is expanded to an area 4 to 20 times the original area.
Inventors
- 👤 Yuji Kodera
- 👤 Kyoichiro Ikari
- 👤 Shunji Miyake
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-01 05:16
CPC Classifications
B; B29; B29C; B29C55/00
Claims Analysis
Total Claims: 16
Claim 1
Independent Claim
87 words
A method of producing an ethylene-vinyl alcohol copolymer film, which comprises: biaxially or multiaxially stretching a nonstretched ethylene-vinylalcohol polymer film having a moisture content of not more than 3.5%, said ethylene-vinyl alcohol copolymer having an ethylene content of 20 to 55 mole % and a saponification degree of not less than 96 mole %, and said stretching being conducted within a temperature range of 50° to 150° C. to such an extent that the film is expanded to an area 4 to 20 times the original area.
Claim 2
Independent Claim
87 words
A method of producing an ethylene-vinyl alcohol copolymer film, which comprises: biaxially or multiaxially stretching a nonstretched ethylene-vinylalcohol polymer film having a moisture content of not more than 3.5%, said ethylene-vinyl alcohol copolymer having an ethylene content of 20 to 55 mole % and a saponification degree of not less than 96 mole %, and said stretching being conducted within a temperature range of 50° to 150° C. to such an extent that the film is expanded to an area 4 to 20 times the original area.
Claim 3
Dependent Claim
20 words
The method of claim 1, wherein the ethylene-vinyl alcohol copolymer has an ethylene content of 30 to 45 mole %.
Claim 4
Dependent Claim
20 words
The method of claim 1, wherein the ethylene-vinyl alcohol copolymer has a saponification degree of not less than 98 mole%.
Claim 5
Dependent Claim
42 words
The method of claim 1, wherein the unstretched film formed from said copolymer has a density which satisfies the condition: d<1.320-4.3×10.sup.-3 X (g/ml) wherein d is density at 25° C. and X is the ethylene content of the copolymer in mole %.
Claim 6
Dependent Claim
22 words
The method of claim 1, wherein the unstretched film formed from said copolymer has a moisture content of not more than 2.0%.
Claim 7
Dependent Claim
18 words
The method of claim 1, wherein stretching is conducted within a temperature range of 50° to 100° C.
Claim 8
Dependent Claim
18 words
The method of claim 1, wherein said film is biaxially stretched simultaneously in the longitudinal and transverse directions.
Claim 9
Dependent Claim
24 words
The method of claim 1, wherein said film is biaxially stretched in separate steps in the longitudinal and transverse directions at the same temperature.
Claim 10
Dependent Claim
23 words
The method of claim 1, wherein said film is biaxially stretched in separate steps in the longitudinal and transverse directions at different temperatures.
Claim 11
Dependent Claim
11 words
The ethylene-vinylalcohol copolymer film produced by the process of claim 1.
Claim 12
Independent Claim
116 words
A method of producing an ethylene-vinyl alcohol copolymer film, which comprises: biaxially or multiaxially stretching a nonstretched ethylene-vinylalcohol copolymer film having a moisture content of not more than 3.5%, said ethylene-vinyl alcohol copolymer having an ethylene content of 20 to 55 mole % and a saponification degree of not less than 96 mole %, and said stretching being conducted within a temperature range of 50° to 150° C. to such an extent that the film is expanded to an area 4 to 20 times the original area; and heat treating said stretched film at a temperature in the range between 100° C. and a temperature lower than the melting point of said copolymer by 10° C.
Claim 13
Independent Claim
116 words
A method of producing an ethylene-vinyl alcohol copolymer film, which comprises: biaxially or multiaxially stretching a nonstretched ethylene-vinylalcohol copolymer film having a moisture content of not more than 3.5%, said ethylene-vinyl alcohol copolymer having an ethylene content of 20 to 55 mole % and a saponification degree of not less than 96 mole %, and said stretching being conducted within a temperature range of 50° to 150° C. to such an extent that the film is expanded to an area 4 to 20 times the original area; and heat treating said stretched film at a temperature in the range between 100° C. and a temperature lower than the melting point of said copolymer by 10° C.
Claim 14
Dependent Claim
16 words
The method of claim 11, wherein said stretched film is heat treated in a fixed state.
Claim 15
Dependent Claim
32 words
The method of claim 11, wherein said stretched film is heat treated in a relaxed state under controlled conditions such that the shrinkage of the film upon heating does not exceed 20%.
Claim 16
Dependent Claim
11 words
The ethylene-vinylalcohol copolymer film produced by the process of claim 11.
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) | 1984-10-12 | 1985-04-13 | 1985-10-13 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1988-10-12 | 1989-04-13 | 1989-10-13 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1992-10-12 | 1993-04-13 | 1993-10-13 | $7700.00 | Window Closed / Lapsed |