Patent US4694055A successfully refreshed from Google Patents.
US4694055A
Expired / Lapsed
US
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Method for the suspension polymerization of vinyl chloride monomer
Assignee: Shin-Etsu Chemical Co Ltd
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Filing: 1985-06-25
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Granted: 1987-09-15
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Expires: 2005-06-25
Abstract
Abstract The invention provides an improvement in the suspension polymerization of vinyl chloride or a monomer mixture mainly composed of vinyl chloride in an aqueous medium containing a nonionic surface active agent and in the presence of a monomer-soluble polymerization initiator, according to which the aqueous polymerization medium is admixed with a crosslinked copolymer having carboxyl groups such as a copolymer of acrylic acid and diethyleneglycol bisallyl or bismethallyl ether at a moment when the percentage of the monomer conversion is in the range from 1 to 20% so that a polyvinyl chloride resin product of high quality can be obtained having an outstandingly high bulk density and plasticizer absorptivity but still containing an extremely small number of fish eyes.
Inventors
- 👤 Kenichi Itoh
- 👤 Genji Noguki
- 👤 Masanobu Nakahara
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-01 21:50
CPC Classifications
C; C08; C08F; C08F14/00; C08F14/02; C08F14/04; C08F14/06
Claims Analysis
Total Claims: 5
Claim 1
Independent Claim
108 words
In a method for the suspension polymerization of vinyl chloride monomer or a monomer mixture mainly composed of vinyl chloride in an aqueous polymerization medium containing a non-ionic surface active agent and in the presence of a monomer-soluble polymerizatin initiator, an improvement which comprises admixing the aqueous polymerization medium with a water-soluble cross-linked copolymer having carboxyl groups at a moment when the percentage of the monomer conversion is in the range from 1 to 20%, wherein the water-soluble cross-linked copolymer having carboxyl groups is a copolymer of 100 parts by weight of acrylic acid and from 0.05 to 10 parts by weight of diethyleneglycol bisallyl or bismethallyl ether.
Claim 2
Dependent Claim
108 words
In a method for the suspension polymerization of vinyl chloride monomer or a monomer mixture mainly composed of vinyl chloride in an aqueous polymerization medium containing a non-ionic surface active agent and in the presence of a monomer-soluble polymerizatin initiator, an improvement which comprises admixing the aqueous polymerization medium with a water-soluble cross-linked copolymer having carboxyl groups at a moment when the percentage of the monomer conversion is in the range from 1 to 20%, wherein the water-soluble cross-linked copolymer having carboxyl groups is a copolymer of 100 parts by weight of acrylic acid and from 0.05 to 10 parts by weight of diethyleneglycol bisallyl or bismethallyl ether.
Claim 3
Dependent Claim
48 words
The improvement as claimed in claim 1 wherein the amount of the water-soluble cross-linked copolymer having carboxyl groups is in the range from 0.01 to 2 parts by weight per 100 parts by weight of the vinyl chloride monomer or the monomer mixture mainly composed of vinyl chloride.
Claim 4
Dependent Claim
86 words
The improvement as claimed in claim 1 which further comprises admixing the aqueous polymerization medium with a first portion of the water-soluble cross-linked copolymer having carboxyl groups prior to the start of the polymerization reaction, the amount of the said first portion of the copolymer being in the range from 1 to 30% of the overall amount of the copolymer of the first portion and the portion added at a moment when the percentage of the monomer conversion is in the range from 1 to 20%.
Claim 5
Dependent Claim
49 words
The improvement as claimed in claim 3 wherein the overall amount of the water-soluble cross-linked copolymer having carboxyl groups is in the range from 0.01 to 2 parts by weight per 100 parts by weight of the vinyl chloride monomer or the monomer mixture mainly composed of vinyl chloride.
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USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1990-09-14 | 1991-03-16 | 1991-09-15 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1994-09-14 | 1995-03-16 | 1995-09-15 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1998-09-14 | 1999-03-16 | 1999-09-15 | $7700.00 | Window Closed / Lapsed |