Patent US4177343A successfully refreshed from Google Patents.
US4177343A
Expired / Lapsed
US
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Purification of polymer solution
Assignee: Dow Chemical Co
•
Filing: 1977-12-19
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Granted: 1979-12-04
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Expires: 1997-12-19
Abstract
Abstract Undesired impurities in polymer solutions, such as amine scavenging agents or hydrochloric acid, are removed by passing a contaminated polymer solution through a strong acid cation exchange resin bed.
Inventors
- 👤 Calvin E. Pannell
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-09 03:17
CPC Classifications
C; C08; C08G; C08G64/00; C08G64/40; C08G64/406
Claims Analysis
Total Claims: 9
Claim 1
Independent Claim
41 words
A method of removing organic contaminants from a non-aqueous polycarbonate polymer solution containing the same which comprises contacting said polymer solution with a strong acid cation exchange resin effective to remove said contaminants therefrom, and thereafter recovering a purified polymer solution.
Claim 2
Independent Claim
41 words
A method of removing organic contaminants from a non-aqueous polycarbonate polymer solution containing the same which comprises contacting said polymer solution with a strong acid cation exchange resin effective to remove said contaminants therefrom, and thereafter recovering a purified polymer solution.
Claim 3
Dependent Claim
17 words
The method of claim 1 wherein substantially all of the contaminants are removed from the polymer solution.
Claim 4
Dependent Claim
11 words
The method of claim 1 wherein the contaminant is pyridine hydrochloride.
Claim 5
Dependent Claim
17 words
The method of claim 3 wherein substantially all of the contaminant is removed from the polymer solution.
Claim 6
Dependent Claim
23 words
The method of claim 1 wherein the polymer solution comprises a phenolphthalein polycarbonate polymer in a solvent and the contaminant is pyridine hydrochloride.
Claim 7
Dependent Claim
13 words
The method of claim 5 wherein substantially all of the contaminant is removed.
Claim 8
Dependent Claim
16 words
The method of claim 1 wherein the resin is a macroporous strong acid cation exchange resin.
Claim 9
Dependent Claim
16 words
The method of claim 5 wherein the resin is a macroporous strong acid cation exchange resin.
References Cited (Backward Citations)
US2865960A
Cited
US3141005A
Cited
US3036036A
Cited
US3144432A
Cited
US3437639A
Cited
US3939118A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1982-12-03 | 1983-06-04 | 1983-12-04 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1986-12-03 | 1987-06-04 | 1987-12-04 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1990-12-03 | 1991-06-04 | 1991-12-04 | $7700.00 | Window Closed / Lapsed |