Patent US3697495A successfully refreshed from Google Patents.
US3697495A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Preparation of polyvinyl alcohol having improved color properties by treating the polyvinyl ester with ozone
Assignee: EIDP Inc
•
Filing: 1970-08-05
•
Granted: 1972-10-10
•
Expires: 1990-08-05
Abstract
Abstract Polyvinyl alcohol having improved color properties is prepared in a process in which an alcoholic solution of the polyvinyl ester utilized to prepare the polyvinyl alcohol is treated with ozone prior to the alcoholysis of the polyvinyl ester to the corresponding polyvinyl alcohol.
Inventors
- 👤 John E Bristol
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-01 02:52
CPC Classifications
C; C08; C08F; C08F8/00; C08F8/12
Claims Analysis
Total Claims: 6
Claim 1
Independent Claim
26 words
The method of claim 1 wherein the polyvinyl ester contains from about 600 ppm to about 1,000 ppm of ozone per 100 grams of polyvinyl ester.
Claim 2
Dependent Claim
22 words
The method of claim 1 wherein the ozone pretreatment occurs at a temperature of from about 20* C. to about 150* C.
Claim 3
Dependent Claim
22 words
The method of claim 3 wherein the ozone pretreatment occurs at a temperature of from about 45* C. to about 100* C.
Claim 4
Dependent Claim
27 words
The method of claim 1 wherein the ozone is in oxygen or air at a concentration of from about 0.1 percent to about 2 percent, by weight.
Claim 5
Dependent Claim
20 words
The method of claim 5 wherein the ozone is in air at a concentration of about 1 percent, by weight.
Claim 6
Dependent Claim
7 words
Polyvinyl alcohol prepared according to claim 1.
References Cited (Backward Citations)
US2353355A
Cited
US2734048A
Cited
US2850489A
Cited
US2862916A
Cited
GB808108A
Cited
US3033843A
Cited
US3153009A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1975-10-10 | 1976-04-10 | 1976-10-10 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1979-10-10 | 1980-04-10 | 1980-10-10 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1983-10-10 | 1984-04-10 | 1984-10-10 | $7700.00 | Window Closed / Lapsed |