US4959435A
Expired / Lapsed
US
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Oriented optically transparent crystalline syndiotatic vinylaromatic polymer
Assignee: Dow Chemical Co
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Filing: 1989-04-24
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Granted: 1990-09-25
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Expires: 2009-04-24
Abstract
Abstract Oriented, syndiotactic, optically transparent vinylaromatic polymers are prepared by a process comprising heating the polymer to a temperature above its crystalline melting point, cooling the polymer to a temperature less than an orientable temperature at a rate sufficient to avoid substantial crystal formation, and inducing strain into the polymer while at a orientable temperature to induce crystal formation and molecular orientation.
Inventors
- 👤 Jerry T. Seitz
- 👤 Charles A. Berglund
- 👤 Andrew J. Pasztor, Jr.
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-29 11:44
CPC Classifications
B; B29; B29C; B29C55/00; B29C55/005; B29K; B29K2025/00
Claims Analysis
Total Claims: 6
Claim 1
Independent Claim
8 words
An oriented, optically transparent, crystalline, syndiotactic, vinylaromatic polymer.
Claim 2
Dependent Claim
8 words
An oriented, optically transparent, crystalline, syndiotactic, vinylaromatic polymer.
Claim 3
Dependent Claim
11 words
The polymer of claim 1 wherein the vinylaromatic monomer is styrene.
Claim 4
Dependent Claim
31 words
The polymer of claim 1 having a transmittance of at least 50 percent at a wavelength of from 380 nM to 780 nM with a thickness of at least 0.1 mm.
Claim 5
Dependent Claim
16 words
The polymer of claim 3 having said transmittance with a thickness of at least 0.25 mm.
Claim 6
Dependent Claim
15 words
The polymer of claim 1 wherein the crystallinity is greater than 40 percent by weight.
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) | 1993-09-24 | 1994-03-26 | 1994-09-25 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1997-09-24 | 1998-03-26 | 1998-09-25 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2001-09-24 | 2002-03-26 | 2002-09-25 | $7700.00 | Window Closed / Lapsed |