US3947536A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Process for preparing a film of a tapered copolymer of styrene-butadiene or mixtures thereof
Assignee: Denka Co Ltd
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Filing: 1974-04-17
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Granted: 1976-03-30
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Expires: 1994-04-17
Abstract
Abstract A process for producing a film or sheet of a tapered styrenebutadiene copolymer or mixture thereof, which comprises: Melt extruding and then biaxially stretching a tapered styrenebutadiene copolymer with a molecular weight of 40,000 - 250,000, a total styrene content of 50 - 90 wt. %, and a total butadiene content of 40 - 10 wt. %, wherein said tapered styrene-butadiene copolymer contains: (a) more than 5% of the chain portion having a tapering rate of 0.3 - 4 and a styrene content of 30 - 70 wt. %, (b) more than 35% of the chain portion with a styrene content of more than 80 wt. %, and (c) more than 10% of the chain portion with a styrene content from at least 5 wt. % to less than 50 wt. % between high styrene content chain portions which have a styrene content greater than 80 wt. %.
Inventors
- 👤 Shigeki Horiie
- 👤 Susumu Kurematsu
- 👤 Shinichiro Asai
- 👤 Chiaki Saito
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-26 22:51
CPC Classifications
B; B29; B29C; B29C48/00; B29C48/03; B29C48/07; B29C48/08; B29C48/001; B29C48/0017; B29C48/0018; B29C48/0019; B29C48/09; B29C48/10
Claims Analysis
Total Claims: 9
Claim 1
Independent Claim
156 words
A process for producing a film or sheet of a tapered styrene-butadiene copolymer which comprises: melt extruding and then biaxially stretching at a temperature in the range of 60° - 180°C a tapered styrene-butadiene copolymer with a molecular weight of 40,000 - 250,000, a total styrene content of 50 - 90 wt. %, and a total butadiene content of 40 - 10 wt. %, wherein said tapered styrene-butadiene copolymer contains: (a) more than 5% of a chain portion with a tapering rate of 0.3 - 5 and a styrene content of 30 - 70 wt. %, (b) more than 35% of a chain portion with a styrene content of more than 80 wt. %, and (c) more than 10% of a chain portion with a styrene content from at least 5 wt. % to less than 50 wt. % between two high styrene content chain portions which have a styrene content greater than 80 wt. %.
Claim 2
Dependent Claim
156 words
A process for producing a film or sheet of a tapered styrene-butadiene copolymer which comprises: melt extruding and then biaxially stretching at a temperature in the range of 60° - 180°C a tapered styrene-butadiene copolymer with a molecular weight of 40,000 - 250,000, a total styrene content of 50 - 90 wt. %, and a total butadiene content of 40 - 10 wt. %, wherein said tapered styrene-butadiene copolymer contains: (a) more than 5% of a chain portion with a tapering rate of 0.3 - 5 and a styrene content of 30 - 70 wt. %, (b) more than 35% of a chain portion with a styrene content of more than 80 wt. %, and (c) more than 10% of a chain portion with a styrene content from at least 5 wt. % to less than 50 wt. % between two high styrene content chain portions which have a styrene content greater than 80 wt. %.
Claim 3
Dependent Claim
26 words
The process of claim 1, wherein said melt-extruding and stretching is conducted by the inflation method whereby a bi-axial orientation is imparted to the tapered copolymer.
Claim 4
Dependent Claim
44 words
The process of claim 2, wherein said tapered copolymer is stretched by a factor of 1.5 - 25 times in the longitudinal direction of the extruded polymer and by a factor of 1.5 - 8 times in the traversing direction of the extruded polymer.
Claim 5
Dependent Claim
29 words
The process of claim 1, wherein said tapered styrene-butadiene copolymer is admixed with polystyrene together with an anti-oxidant and the mixture is melt-extruded and stretched by an inflation method.
Claim 6
Dependent Claim
25 words
The process of claim 1, wherein said tapered styrene-butadiene copolymer is prepared from a living polymer prepared in the presence of a lithium type catalyst.
Claim 7
Dependent Claim
32 words
The process of claim 1, wherein said tapered styrene-butadiene copolymer is prepared by polymerizing styrene and butadiene in the presence of a randomizer and a lithium type catalyst in a non-polar solvent.
Claim 8
Dependent Claim
24 words
The process of claim 1, wherein said melt extruding and stretching is conducted by the tenter method to produce a biaxially oriented tapered copolymer.
Claim 9
Dependent Claim
29 words
The process of claim 7, wherein said tapered copolymer is stretched by a factor of 1.5 - 8 times in the longitudinal and traversing directions of the extruded polymer.
References Cited (Backward Citations)
GB888624A
Cited
US3629387A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1979-03-30 | 1979-09-29 | 1980-03-30 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1983-03-30 | 1983-09-29 | 1984-03-30 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1987-03-30 | 1987-09-29 | 1988-03-30 | $7700.00 | Window Closed / Lapsed |