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US3671508A
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Method for preparing polyvinyl chloride
Assignee: Shin-Etsu Chemical Co Ltd
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Filing: 1971-03-01
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Granted: 1972-06-20
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Expires: 1991-03-01
Abstract
Abstract Vinyl chloride is suspension polymerized in the presence of a catalyst selected from the group consisting of dialkyl peroxy dicarbonate, azo-bis-2,4-dimethyl valeronitrile, azo-bis-2,4,4trimethyl valero nitrile, azo-bis-4-methoxy-2,4-dimethyl valeronitrile, and acetyl cyclohexyl sulfonyl peroxide, a suspending agent, a fatty alcohol having from eight to 18 carbon atoms and sorbitan oleate. When the rate of conversion reaches at least 50 percent, an organic reducing agent is added to the polymerization system. A polyvinyl chloride having superior particle size distribution, plasticizer absorption, fish eye, initial color and thermal stability is produced.
Inventors
- 👤 Shunichi Koyanagi
- 👤 Hajime Kitamura
- 👤 Shigenobu Tajima
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-05 21:53
CPC Classifications
C; C08; C08F; C08F14/00; C08F14/02; C08F14/04; C08F14/06; Y; Y10; Y10S; Y10S526/00; Y10S526/909
Claims Analysis
Total Claims: 5
Claim 1
Independent Claim
68 words
The method of claim 1 in which the catalyst is selected from the group consisting of di-isobutyl peroxy dicarbonate, di-isopropyl peroxy dicarbonate, di-2-ethyl-hexylperoxy dicarbonate, di-cyclohexyl-peroxy dicarbonate, bis-1,4-tertiary-butyl cyclohexyl peroxy dicarbonate, azo-bis-2,4-dimethylvaleronitrile, azo-bis-2,4,4-trimethyl valeronitrile, azo-bis-4-methoxy-2,4-dimethylvaleronitrile and acetylcyclohexysulfonyl peroxide, and the catalyst is present in an amount of at most 0.2 percent by weight, based on the weight of the vinyl chloride or mixture of vinyl monomers containing vinyl chloride.
Claim 2
Dependent Claim
63 words
The method of claim 1 in which the fatty alcohol is selected from the group consisting of octyl alcohol, decanoyl alcohol, lauryl alcohol, myristyl alcohol, cetyl alcohol and stearyl alcohol and the fatty alcohol is present in an amount of from 0.03 to 0.1 percent by weight, based on the weight of the vinyl chloride or mixture of vinyl monomers containing vinyl chloride.
Claim 3
Dependent Claim
57 words
The method of claim 1 in which the sorbitan oleate is selected from the group consisting of sorbitan monooleate, sorbitan trioleate and sorbitan sesquioleate, and the sorbitan oleate is present in an amount of from 0.01 to 0.5 percent by weight based on the weight of the vinyl chloride or mixture of vinyl monomers containing vinyl chloride.
Claim 4
Dependent Claim
40 words
The method of claim 1 in which the organic reducing agent is added in an amount of from 0.005 to 0.5 percent by weight based on the weight of the vinyl chloride or mixture of vinyl monomers containing vinyl chloride.
Claim 5
Dependent Claim
35 words
The method of claim 1 in which the organic reducing agent is added to the reaction medium on completion of the polymerization of the vinyl chloride or the mixture of vinyl monomers containing vinyl chloride.
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) | 1975-06-20 | 1975-12-20 | 1976-06-20 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1979-06-20 | 1979-12-20 | 1980-06-20 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1983-06-20 | 1983-12-20 | 1984-06-20 | $7700.00 | Window Closed / Lapsed |