US4367323A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Production of hydrogels
Assignee: Sumitomo Chemical Co Ltd
•
Filing: 1981-12-02
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Granted: 1983-01-04
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Expires: 2001-12-02
Abstract
Abstract The invention is to provide the methods for producing highly water-absorbable and water-retainable hydrogels having a large particle diameter together with a sufficient gel strength. The method is characterized by use of a specific dispersing agent in the water-in-oil type inverse phase suspension polymerization of an α,β-unsaturated carboxylic acid and/or its alkali metal salt. Due to the high water-absorbability and water-retainability, along with the superior gel strength and the stable gel structure, the hydrogels of the invention enlarge the conventional range of usages.
Inventors
- 👤 Shuji Kitamura
- 👤 Fumio Fujita
- 👤 Toshihiro Oonishi
- 👤 Yoshiharu Tatsukami
- 👤 Masato Ogura
- 👤 Masahiro Niwano
- 👤 Masaru Oota
- 👤 Toshifumi Tamura
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-24 16:04
CPC Classifications
C; C08; C08F; C08F20/00; C08F20/02; C08F20/04; C08F20/06; A; A61; A61L; A61L15/00; A61L15/16; A61L15/42; A61L15/60; C09; C09K; C09K17/00; C09K17/14; C09K17/18; C09K17/20; C09K17/22
Claims Analysis
Total Claims: 5
Claim 1
Independent Claim
54 words
A method for producing hydrogels which comprises that, in producing the hydrogel by water-in-oil type inverse phase suspension polymerization of an α,β-unsaturated carboxylic acid monomer and/or its alkali metal salt in the presence or absence of a cross-linking agent, a carboxyl-containing polymer having affinity to the organic solvent is used as the dispersing agent.
Claim 2
Independent Claim
54 words
A method for producing hydrogels which comprises that, in producing the hydrogel by water-in-oil type inverse phase suspension polymerization of an α,β-unsaturated carboxylic acid monomer and/or its alkali metal salt in the presence or absence of a cross-linking agent, a carboxyl-containing polymer having affinity to the organic solvent is used as the dispersing agent.
Claim 3
Dependent Claim
60 words
The method for producing hydrogels according to claim 1, wherein the carboxyl-containing polymer is selected from the group consisting of methacrylic acid-methyl acrylate-2-ethylhexyl acrylate copolymer; reaction product from maleic anhydride-modified liquid polybutadiene and 2-hydroxyethyl methacrylate; graft polymer of ethylene-propylene-monomeric diene copolymer grafted with an α,β-unsaturated carboxylic acid and an alkyl or hydroxyalkyl α,β-unsaturated carboxylate; and polybutadiene-butyl methacrylate-methacrylic acid graft copolymer.
Claim 4
Dependent Claim
22 words
The method for producing hydrogels according to claim 1, wherein the α,β-unsaturated carboxylic acid is any of acrylic acid and methacrylic acid.
Claim 5
Dependent Claim
23 words
The method for producing hydrogels according to claim 1, wherein the organic solvent is any of hexane, heptane, cyclohexane, benzene, xylene and toluene.
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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) | 1986-01-03 | 1986-07-05 | 1987-01-04 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1990-01-03 | 1990-07-05 | 1991-01-04 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1994-01-03 | 1994-07-05 | 1995-01-04 | $7700.00 | Window Closed / Lapsed |