US4541871A
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: 1984-08-07
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Granted: 1985-09-17
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Expires: 2004-08-07
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
2026-11-05 14:52
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: 12
Claim 1
Independent Claim
159 words
A process for producing a water-absorbent resin having an improved water-absorbency, which comprises crosslinking a water-absorbent resin comprising a carboxylate as a constitutent of the resin selected from the group consisting of crosslinked polyacrylic acid salts, crosslinked copolymers of acrylic acid salt and methacrylic acid salt, crosslinked saponification products of methyl acrylate-vinyl acetate copolymer, crosslinked saponification products of starch-ethyl acrylate graft copolymer, crosslinked starch-acrylic acid salt graft copolymer, crosslinked saponification products of starch-methyl methacrylate graft copolymer, crosslinked saponification products of starch-acrylonitrile graft copolymer and crosslinked sodium carboxymethyl cellulose, with 0.005-5% by weight of a crosslinking agent selected from the group consisting of diglycidyl ether compounds, haloepoxy compounds, aldehyde compounds and isocyanate compounds 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 inert solvent which does not affect the water-absorbent resin.
Claim 2
Dependent Claim
159 words
A process for producing a water-absorbent resin having an improved water-absorbency, which comprises crosslinking a water-absorbent resin comprising a carboxylate as a constitutent of the resin selected from the group consisting of crosslinked polyacrylic acid salts, crosslinked copolymers of acrylic acid salt and methacrylic acid salt, crosslinked saponification products of methyl acrylate-vinyl acetate copolymer, crosslinked saponification products of starch-ethyl acrylate graft copolymer, crosslinked starch-acrylic acid salt graft copolymer, crosslinked saponification products of starch-methyl methacrylate graft copolymer, crosslinked saponification products of starch-acrylonitrile graft copolymer and crosslinked sodium carboxymethyl cellulose, with 0.005-5% by weight of a crosslinking agent selected from the group consisting of diglycidyl ether compounds, haloepoxy compounds, aldehyde compounds and isocyanate compounds 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 inert solvent which does not affect the water-absorbent resin.
Claim 3
Dependent Claim
24 words
A process according to claim 1, wherein the water-absorbent resin is a crosslinked saponification product of starch-acrylonitrile graft copolymer or crosslinked sodium carboxymethyl cellulose.
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 part 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 ethylene glycol diglycidyl ether.
Claim 10
Dependent Claim
33 words
A process according to claim 1, wherein said crosslinking agent is a diglycidyl ether compound and said water-absorbent resin is a crosslinked saponification product of starch-acrylonitrile graft copolymer or crosslinked sodium carboxymethyl cellulose.
Claim 11
Dependent Claim
20 words
A process according to claim 1, wherein the crosslinking is carried out while said resin is in the dispersion form.
Claim 12
Dependent Claim
15 words
A water-absorbent resin having an improved water-absorbency obtained by the process according to claim 1.
References Cited (Backward Citations)
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US3966679A
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US4041228A
Cited
JPS51136588A
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US4351922A
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EP0036463A2
Cited
US4340706A
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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) | 1988-09-16 | 1989-03-18 | 1989-09-17 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1992-09-16 | 1993-03-18 | 1993-09-17 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1996-09-16 | 1997-03-18 | 1997-09-17 | $7700.00 | Window Closed / Lapsed |