US3621085A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Production of light-polarizing film
Assignee: Toyobo Co Ltd
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Filing: 1969-03-20
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Granted: 1971-11-16
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Expires: 1989-03-20
Abstract
Abstract A light-polarizing film of a polymer selected from the group consisting of polyvinyl chloride, polyvinyl bromide and polyvinylidene chloride is produced by heating the polymer at a temperature of 90*-150* C. in the presence of a tertiary aliphatic amine having a boiling point higher than 90* C. as dehydrohalogenating agent to cause partial dehydro-halogenation, heating the product at a temperature of 70* -150* C. to produce conjugated double bond chains, and then molecularly orienting the product in at least one direction by stretching the product more than 1.2 times its length at a temperature above 100* C.
Inventors
- 👤 Rinjiro Ichikawa
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-24 03:22
CPC Classifications
G; G02; G02B; G02B5/00; G02B5/30; G02B5/3025; G02B5/3033
Claims Analysis
Total Claims: 4
Claim 1
Independent Claim
14 words
A process as claimed in claim 1 wherein the dehydrohalogenating agent is an N,N-dialkylamide.
Claim 2
Dependent Claim
18 words
A process as claimed in claim 1 wherein the starting polymer is in the form of a film.
Claim 3
Dependent Claim
22 words
A process as claimed in claim 1 wherein the stretching is conducted in two directions substantially at right angles with each other.
Claim 4
Dependent Claim
18 words
A process as claimed in claim 4 wherein the stretching ratio in tWo directions is at least 1.5.
References Cited (Backward Citations)
No citation records indexed.
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1974-11-15 | 1975-05-17 | 1975-11-16 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1978-11-15 | 1979-05-17 | 1979-11-16 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1982-11-15 | 1983-05-17 | 1983-11-16 | $7700.00 | Window Closed / Lapsed |