Patent US4507438A successfully refreshed from Google Patents.
US4507438A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Water-absorbent resin having improved water-absorbency and improved water-dispersibility and process for producing same
Assignee: Sumitomo Seika Chemicals Co Ltd
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Filing: 1982-12-09
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Granted: 1985-03-26
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Expires: 2002-12-09
Abstract
Abstract Water-absorbent resins having improved water-absorbency, water-absorption rate and water-dispersibility can be produced by crosslinking a water-absorbent resin comprising a carboxylate as a constituent of the resin with a crosslinking agent having at least two functional groups in the presence of water in a proportion of 0.01 to 1.3 parts by weight per part by weight of the resin in an inert solvent.
Inventors
- 👤 Shigeji Obayashi
- 👤 Morio Nakamura
- 👤 Takushi Yamamoto
- 👤 Masato Fujikake
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-08 04:14
CPC Classifications
C; C08; C08L; C08L33/00; C08L33/02; A; A61; A61L; A61L15/00; A61L15/16; A61L15/42; A61L15/60; C08L63/00
Claims Analysis
Total Claims: 17
Claim 1
Independent Claim
119 words
A process for producing a water-absorbent resin having an improved water-absorbency, characterized by crosslinking a crosslinked carboxylate-containing water-absorbent resin wherein said resin is acrylate homopolymer, acrylate copolymer, methacrylate homopolymer, or methacrylate copolymer with 0.005-5% by weight of a crosslinking agent having at least two functional groups capable of reacting with a reactive group of said resin wherein said reactive group is selected from the class of carboxylate, hydroxyl, sulfonic acid, and amino in the presence of water in a proportion of 0.01 to 1.3 parts by weight per part by weight of the resin in 0.1 to 50 parts by weight, per part by weight of said resin of an invert solvent which does not affect the water-absorbent resin.
Claim 2
Dependent Claim
119 words
A process for producing a water-absorbent resin having an improved water-absorbency, characterized by crosslinking a crosslinked carboxylate-containing water-absorbent resin wherein said resin is acrylate homopolymer, acrylate copolymer, methacrylate homopolymer, or methacrylate copolymer with 0.005-5% by weight of a crosslinking agent having at least two functional groups capable of reacting with a reactive group of said resin wherein said reactive group is selected from the class of carboxylate, hydroxyl, sulfonic acid, and amino in the presence of water in a proportion of 0.01 to 1.3 parts by weight per part by weight of the resin in 0.1 to 50 parts by weight, per part by weight of said resin of an invert solvent which does not affect the water-absorbent resin.
Claim 3
Dependent Claim
22 words
A process according to claim 1, wherein the water-absorbent resin is a polymer comprising an alkali acrylate or methacrylate as a constituent.
Claim 4
Dependent Claim
29 words
A process according to claim 1, wherein the water is present in a proportion of 0.05 to 1.0 parts by weight per part by weight of the water-absorbent resin.
Claim 5
Dependent Claim
30 words
A process according to claim 1, wherein the inert solvent is used in a proportion of 0.2 to 20 parts by weight per part by weight of the water-absorbent resin.
Claim 6
Dependent Claim
12 words
A process according to claim 1, wherein the inert solvent is methanol.
Claim 7
Dependent Claim
12 words
A process according to claim 1, wherein the inert solvent is cyclohexane.
Claim 8
Dependent Claim
12 words
A process according to claim 1, wherein the inert solvent is n-heptane.
Claim 9
Dependent Claim
15 words
A process according to claim 1, wherein the crosslinking agent is a diglycidyl ether compound.
Claim 10
Dependent Claim
15 words
A process according to claim 8, wherein the crosslinking agent is ethylene glycol diglycidyl ether.
Claim 11
Dependent Claim
15 words
A water-absorbent resin having an improved water-absorbency obtained by the process according to claim 1.
Claim 12
Dependent Claim
25 words
The process of claim 1 wherein said crosslinking agent is selected from the group of diglycidyl ether compounds, haloepoxy compounds, aldehyde compounds, and isocyanate compounds.
Claim 13
Dependent Claim
52 words
The process of claim 1 wherein said water-absorbent resin is selected from the group of polyacrylic acid salts, copolymers of acrylic acid salt and methacrylic acid salt, saponification products of methylacrylate-vinyl acetate copolymer, saponification products of starch-ethylacrylate graft copolymer, starch-acrylic acid salt graft copolymer, and saponification products of starch-methyl methacrylate graft copolymer.
Claim 14
Dependent Claim
15 words
The process of claim 1 wherein said water-absorbent resin is an acrylate homopolymer or copolymer.
Claim 15
Dependent Claim
24 words
The process of claim 1 wherein said crosslinking agent is a diglycidyl ether compound and said water-absorbent resin is an acrylic homopolymer or copolymer.
Claim 16
Dependent Claim
18 words
The process of claim 1 wherein the crosslinking is carried out while said resin is in dispersion form.
Claim 17
Dependent Claim
13 words
The process of claim 14 wherein said resin is a polyacrylic acid salt.
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) | 1988-03-25 | 1988-09-24 | 1989-03-26 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1992-03-25 | 1992-09-24 | 1993-03-26 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1996-03-25 | 1996-09-24 | 1997-03-26 | $7700.00 | Window Closed / Lapsed |