Patent US4524186A successfully refreshed from Google Patents.
US4524186A
Expired / Lapsed
US
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Process for producing water-absorbing resins
Assignee: Fujikura Kasei Co Ltd
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Filing: 1983-07-27
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Granted: 1985-06-18
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Expires: 2003-07-27
Abstract
Abstract A process for producing an absorbent resin, which comprises polymerizing 1 mole of a lower alkyl acrylate and 0.07 to 0.5 mole of a polyhydric alcohol ester of a monoethylenically unsaturated carboxylic acid in an aqueous medium in the absence of an emulsifying agent, saponifying the resulting polymer with a basic substance in a water-lower alcohol medium, and then neutalizing the saponification product with an acid.
Inventors
- 👤 Hiroshi Nagase
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-31 13:41
CPC Classifications
C; C08; C08F; C08F8/00; C08F8/12; C08F8/44; C08F220/00; C08F220/02; C08F220/10; C08F220/12; C08F220/16; C08F220/18; C08F220/1802; C08F220/1804
Claims Analysis
Total Claims: 23
Claim 1
Independent Claim
72 words
A process for producing an absorbent resin, which comprises polymerizing 1 mole of a lower alkyl acrylate and 0.07 to 0.5 mole of a polyhydric alcohol ester of a monoethylenically unsaturated carboxylic acid in an aqueous medium in the absence of an emulsifying agent, saponifying the resulting polymer with a basic substance in a water-lower alcohol medium to produce a gel-like saponification product, and then neutralizing the saponification product with an acid.
Claim 2
Dependent Claim
72 words
A process for producing an absorbent resin, which comprises polymerizing 1 mole of a lower alkyl acrylate and 0.07 to 0.5 mole of a polyhydric alcohol ester of a monoethylenically unsaturated carboxylic acid in an aqueous medium in the absence of an emulsifying agent, saponifying the resulting polymer with a basic substance in a water-lower alcohol medium to produce a gel-like saponification product, and then neutralizing the saponification product with an acid.
Claim 3
Dependent Claim
16 words
The process of claim 1 wherein the lower alkyl acrylate is methyl acrylate or ethyl acrylate.
Claim 4
Dependent Claim
17 words
The process of claim 1 wherein the monoethylenically unsaturated carboxylic acid contains 3 to 5 carbon atoms.
Claim 5
Dependent Claim
23 words
The process of claim 3 wherein the monoethylenically unsaturated carboxylic acid is acrylic acid, methacrylic acid, crotonic acid, isocrotonic acid or angelic acid.
Claim 6
Dependent Claim
21 words
The process of claim 1 wherein the polyhydric alcohol has 2 to 46 carbon atoms and 2 or 3 hydroxyl groups.
Claim 7
Dependent Claim
28 words
The process of claim 1 wherein the polyhydric alcohol is ethylene glycol, propylene glycol, isopropylene glycol, butylene glycol, neopentylene glycol, glycerol, polyethylene glycol, polypropylene glycol, or polyisopropylene glycol.
Claim 8
Dependent Claim
24 words
The process of claim 1 wherein the polyhydric alcohol ester is hydroxyethyl acrylate, hydroxethyl methacrylate, hydroxypropyl acrylate, hydroxypropyl methacrylate, hydroxybutyl acrylate or hydroxybutyl methacrylate.
Claim 9
Dependent Claim
13 words
The process of claim 7 wherein the polyhydric alcohol ester is hydroxyethyl methacrylate.
Claim 10
Dependent Claim
25 words
The process of claim 1 wherein the amount of the polyhydric alcohol ester is 0.09 to 0.2 mole per mole of the lower alkyl acrylate.
Claim 11
Dependent Claim
11 words
The process of claim 1 wherein the aqueous medium is water.
Claim 12
Dependent Claim
18 words
The process of claim 1 wherein the polymerization is carried out in the absence of a polymerization initiator.
Claim 13
Dependent Claim
13 words
The process of claim 11 wherein the polymerization initiator is a persulfate salt.
Claim 14
Dependent Claim
26 words
The process of claim 11 wherein the amount of the polymerization initiator is 0.01 to 1% by weight based on the total weight of the monomers.
Claim 15
Dependent Claim
12 words
The process of claim 1 wherein the basic substance is sodium hydroxide.
Claim 16
Dependent Claim
24 words
The process of claim 1 wherein the amount of the basic substance is 0.9 to 1.5 equivalents per mole of the lower alkyl acrylate.
Claim 17
Dependent Claim
15 words
The process of claim 1 wherein the lower alcohol is methanol, ethanol, n-propanol or isopropanol.
Claim 18
Dependent Claim
30 words
The process of claim 1 wherein the amount of the lower alcohol is 65 to 200 parts by weight per 100 parts by weight of water in the reaction system.
Claim 19
Dependent Claim
23 words
The process of claim 1 wherein the saponification is carried out at about 65° C. to the refluxing temperature of the reaction mixture.
Claim 20
Dependent Claim
20 words
The process of claim 1 wherein the saponification reaction is completed while evaporating a part of the water-lower alcohol azeotrope.
Claim 21
Dependent Claim
19 words
The process of claim 1 wherein the neutralization with the acid is carried out by using 0.5-3N hydrochloric acid.
Claim 22
Dependent Claim
22 words
The process of claim 1 wherein after the neutralization with the acid, the polymer is successively washed with an alcohol and acetone.
Claim 23
Dependent Claim
10 words
A water-absorbing resin prepared by the process of claim 1.
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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) | 1988-06-17 | 1988-12-17 | 1989-06-18 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1992-06-17 | 1992-12-17 | 1993-06-18 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1996-06-17 | 1996-12-17 | 1997-06-18 | $7700.00 | Window Closed / Lapsed |