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US4258163A
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Partially saponified polyvinyl acetates and their application in the homo- and copolymerization of vinyl chloride
Assignee: Borsodi Vegyi Kombinat Rt
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Filing: 1979-05-23
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Granted: 1981-03-24
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Expires: 1999-05-23
Abstract
Abstract This invention relates to novel partially saponified polyvinyl acetates with a degree of hydrolysis of 30 to 65 mole % which might be considered as vinyl alcohol-vinyl acetate block copolymers. The invention relates further to the application of said novel block copolymers as a pore-forming additive used together with at least one known protective colloid in the homo- and copolymerization of vinyl compounds, primarily of vinyl chloride in a pure aqueous medium.
Inventors
- 👤 Bela Mariasi
- 👤 Laszlo Molnar
- 👤 Janos Toth
- 👤 Imre Gulya
- 👤 Miklos Nagy
- 👤 Ervin Wolfram
- 👤 Miklos Zrinyi
- 👤 Gaborne Kovacs
- 👤 Laszlone Jaksity
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-05 11:06
CPC Classifications
C; C08; C08F; C08F8/00; C08F8/12; C08F8/28; C08F2810/00; C08F2810/20
Claims Analysis
Total Claims: 4
Claim 1
Independent Claim
141 words
A process for the homo- and copolymerization of vinyl chloride in the presence of 0.03 to 0.3 w% of at least one protective colloid, comprising in an aqueous medium using as a pore-forming additive in a quantity of about 0.01 to 0.4 weight % with reference to the weight of the vinyl chloride used a partially saponified polyvinyl acetate (vinyl acetate-vinyl alcohol copolymer) having a degree of hydrolysis of about 30 to 65 mole%, a degree of polymerization of about 100 to 6000 and having a block structure; said partially saponified polyvinyl acetate being further characterized by forming a gel with bifunctional aldehydes in an acid catalyzed reaction within a shorter period of time than needed for the formation of a gel under identical conditions from a partially saponified polyvinyl acetate of identical acetate content having a structure of statistical distribution.
Claim 2
Dependent Claim
141 words
A process for the homo- and copolymerization of vinyl chloride in the presence of 0.03 to 0.3 w% of at least one protective colloid, comprising in an aqueous medium using as a pore-forming additive in a quantity of about 0.01 to 0.4 weight % with reference to the weight of the vinyl chloride used a partially saponified polyvinyl acetate (vinyl acetate-vinyl alcohol copolymer) having a degree of hydrolysis of about 30 to 65 mole%, a degree of polymerization of about 100 to 6000 and having a block structure; said partially saponified polyvinyl acetate being further characterized by forming a gel with bifunctional aldehydes in an acid catalyzed reaction within a shorter period of time than needed for the formation of a gel under identical conditions from a partially saponified polyvinyl acetate of identical acetate content having a structure of statistical distribution.
Claim 3
Dependent Claim
105 words
A process as claimed in claim 1, wherein the partially saponified polyvinyl acetate is prepared by way of alkali catalyzed saponification, wherein the saponification is performed in the gel phase in a mixture containing minimum 50 volume % and maximum 98 volume % at least one non-polar organic solvent to make up the volume to 100% and minimum about 5 w/v% and maximum about 60 w/v% of polyvinyl acetate of appropriate degree of polymerization, further a minimum of about 0.1 w/v% and a maximum of about 10 w/v% of at least one hydroxide of an alkali metal and/or of an alkaline earth metal is dissolved.
Claim 4
Dependent Claim
26 words
A process as claimed in claim 2, characterized in that the saponification is carried out at a temperature between about 10° C. and about 80° C.
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) | 1984-03-23 | 1984-09-22 | 1985-03-24 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1988-03-23 | 1988-09-22 | 1989-03-24 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1992-03-23 | 1992-09-22 | 1993-03-24 | $7700.00 | Window Closed / Lapsed |