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US4456731A
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Composition for lining the walls of reactors and connected apparatus used for polymerizing vinyl compounds which prevents or reduces deposits and incrustations on said apparatus, and the method for its use
Assignee: VINAVIL SpA
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Filing: 1982-03-01
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Granted: 1984-06-26
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Expires: 2002-03-01
Abstract
Abstract A composition for lining the walls of reactors and other connected apparatus in contact with reactant mixtures and reaction products during the polymerization of vinyl compounds, which reduces or prevents polymer deposits or incrustations on the said walls, constituted by the product of the prolonged reaction at 75° C. between a polyvinyl alcohol of medium degree of hydrolysis prepared by the controlled alkaline alcoholysis of an ester of a wide molecular weight distribution polyvinyl alcohol and a polycarboxylic oxyacid, in a weight ratio of beween 35:10 and 40:10, which is applicable by known means, preferably by spraying.
Inventors
- 👤 Adolfo Caporossi
- 👤 Leonello Del Signore
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-03 06:48
CPC Classifications
C; C08; C08F; C08F2/00; C08F2/002; C08F2/004; C08F8/00; C08F8/14
Claims Analysis
Total Claims: 7
Claim 1
Independent Claim
63 words
A composition useful as a lining for the walls of reactors and other apparatus connected thereto, said lining capable of substantially preventing or reducing polymer deposition and the formation of incrustations on said walls during the polymerizations of vinyl compounds therein, said composition comprised of the tartaric acid ester of a polyvinyl alcohol having a saponification number between about 270 and about 400.
Claim 2
Dependent Claim
63 words
A composition useful as a lining for the walls of reactors and other apparatus connected thereto, said lining capable of substantially preventing or reducing polymer deposition and the formation of incrustations on said walls during the polymerizations of vinyl compounds therein, said composition comprised of the tartaric acid ester of a polyvinyl alcohol having a saponification number between about 270 and about 400.
Claim 3
Dependent Claim
39 words
A composition as defined in claim 1 wherein said ester is formed by the reaction of tartaric acid with said polyvinyl alcohol at a temperature between about 60° C. and about 80° C. for at least about 20 minutes.
Claim 4
Dependent Claim
20 words
A composition as defined in claim 2 wherein said reaction temperature is between about 70° C. and about 80° C.
Claim 5
Dependent Claim
15 words
A composition as defined in claim 3 wherein said reaction temperature is about 75° C.
Claim 6
Dependent Claim
30 words
A composition as defined in claim 2 wherein the weight ratio of said polyvinyl alcohol to said tartaric acid is between about 35 to 10 and about 40 to 10.
Claim 7
Dependent Claim
30 words
A composition as defined in claim 2 wherein said polyvinyl alcohol is prepared by alkaline hydrolysis of polyvinyl acetate at an hourly hydrolysis rate between about 40% and about 60%.
References Cited (Backward Citations)
US3050418A
Cited
US3220991A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1987-06-26 | 1987-12-26 | 1988-06-26 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1991-06-26 | 1991-12-26 | 1992-06-26 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1995-06-26 | 1995-12-26 | 1996-06-26 | $7700.00 | Window Closed / Lapsed |