US4155893A
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Preparing a hydrophilic gel by hydrolyzing a vinyl ester-acrylic or methacrylic ester copolymer
Assignee: Sumitomo Chemical Co Ltd
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Filing: 1977-10-13
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Granted: 1979-05-22
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Expires: 1997-10-13
Abstract
Abstract A method for the preparation of water-insoluble gels containing at least a hydroxyl group and a carboxylate group in molecules thereof which comprises saponifying copolymers comprising a vinyl ester component and an acrylic or methacrylic acid ester component or terpolymers comprising said two components and an ethylene component in the presence of an alkali catalyst and a solvent under conditions in which said copolymers or terpolymers are not dissolved.
Inventors
- 👤 Masanori Fujimoto
- 👤 Toshifumi Tamura
- 👤 Tsuneyuki Nagase
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-23 18:39
CPC Classifications
C; C08; C08F; C08F8/00; C08F8/42; C08F2800/00; C08F2800/10
Claims Analysis
Total Claims: 30
Claim 1
Independent Claim
147 words
A method for the preparation of a water-insoluble hydrophilic gel comprising a high - molecular weight copolymer containing hydroxyl groups and carboxylate groups in the molecule, which comprises saponifying a copolymer consisting essentially of a vinyl ester component (X) and an acrylic or methacrylic acid ester component (Y) in the range of the molar ratio, X:Y=20:80: to 80:20 or a terpolymer consisting essentially of (X) and (Y) components and an ethylene component (Z) in the range of the molar ratio, X:Y=20:80 to 80:20 Z:(X+Y)=0.1:99.9 to 15:85 in the presence of an alkaline catalyst and a solvent under conditions in which said copolymer or terpolymer is not dissolved, the saponification degree of the vinyl ester in said copolymer or terpolymer being 50 mole % or more and the saponification degree of the acrylic or methacrylic acid ester in said copolymer or terpolymer being 30 mole % or more.
Claim 2
Independent Claim
147 words
A method for the preparation of a water-insoluble hydrophilic gel comprising a high - molecular weight copolymer containing hydroxyl groups and carboxylate groups in the molecule, which comprises saponifying a copolymer consisting essentially of a vinyl ester component (X) and an acrylic or methacrylic acid ester component (Y) in the range of the molar ratio, X:Y=20:80: to 80:20 or a terpolymer consisting essentially of (X) and (Y) components and an ethylene component (Z) in the range of the molar ratio, X:Y=20:80 to 80:20 Z:(X+Y)=0.1:99.9 to 15:85 in the presence of an alkaline catalyst and a solvent under conditions in which said copolymer or terpolymer is not dissolved, the saponification degree of the vinyl ester in said copolymer or terpolymer being 50 mole % or more and the saponification degree of the acrylic or methacrylic acid ester in said copolymer or terpolymer being 30 mole % or more.
Claim 3
Dependent Claim
27 words
A method according to claim 1 wherein the molar ratio of X to Y in said copolymer or terpolymer is in the range of 30:70 to 70:30.
Claim 4
Dependent Claim
27 words
A method according to claim 1 wherein the molar ratio of X to Y in said copolymer or terpolymer is in the range of 40:60 to 60:40.
Claim 5
Dependent Claim
26 words
A method according to claim 1 wherein said vinyl ester is a member selected from the group consisting of vinyl acetate, vinyl propionate and vinyl stearate.
Claim 6
Dependent Claim
13 words
A method according to claim 4 wherein the vinyl ester is vinyl acetate.
Claim 7
Dependent Claim
36 words
A method according to claim 1 wherein said acrylic or methacrylic acid ester is a member selected from the group consisting of methyl, ethyl, n-propyl, isopropyl, n-butyl and t-butyl esters of acrylic acid and methacrylic acid.
Claim 8
Dependent Claim
19 words
A method according to claim 6 wherein the acrylic or methacrylic acid ester is methyl acrylate or methyl methacrylate.
Claim 9
Dependent Claim
29 words
A method according to claim 1 wherein said solvent used for saponification is a mixture of water and alcohol having a water content of 0.01 to 40% by weight.
Claim 10
Dependent Claim
16 words
A method according to claim 8 wherein said water content is 5 to 35% by weight.
Claim 11
Dependent Claim
19 words
A method according to claim 8 wherein said alcohol is an alkyl alcohol having 1 to 4 carbon atoms.
Claim 12
Dependent Claim
11 words
A method according to claim 10 wherein the alcohol is methanol.
Claim 13
Dependent Claim
15 words
A method according to claim 1 wherein said alkaline catalyst is an alkaline metal hydroxide.
Claim 14
Dependent Claim
16 words
A method according to claim 12 wherein the alkaline catalyst is sodium hydroxide or potassium hydroxide.
Claim 15
Dependent Claim
38 words
A method according to claim 1 wherein the amount of alkaline catalyst is 0.5 to 2 times by mole based on the vinyl ester component and the acrylic or methacrylic acid ester component in the copolymer or terpolymer.
Claim 16
Dependent Claim
19 words
A method according to claim 14 wherein said amount of alkaline catalyst is 1 to 2 times by mole.
Claim 17
Dependent Claim
17 words
A method according to claim 1 wherein the saponification is carried out at 20° to 80° C.
Claim 18
Dependent Claim
25 words
A method according to claim 16 wherein the saponification is carried out at 20° to 30° C. at first and then at an elevated temperature.
Claim 19
Dependent Claim
16 words
A method according to claim 1 wherein said copolymer or terpolymer is of a spherical form.
Claim 20
Dependent Claim
17 words
A method according to claim 18 wherein the copolymer or terpolymer is that obtained by suspension polymerization.
Claim 21
Dependent Claim
16 words
A method according to claim 1 wherin said copolymer or terpolymer is of a fibrous form.
Claim 22
Dependent Claim
20 words
A method according to claim 1 wherein said saponification degree of the vinyl ester is 90 mole % or more.
Claim 23
Dependent Claim
23 words
A method according to claim 1 wherein said saponification degree of the acrylic or methacrylic acid ester is 70 mole % or more.
Claim 24
Dependent Claim
40 words
A method according to claim 8 wherein there is employed 300 to 10,000 parts by weight of solvent per 100 parts by weight of copolymer or terpolymer and the alcohol is an alkyl alcohol having 1 to 4 carbon atoms.
Claim 25
Dependent Claim
27 words
A method according to claim 23 wherein there is employed 500 to 2,000 parts by weight of solvent per 100 parts by weight of copolymer or terpolymer.
Claim 26
Dependent Claim
16 words
A method according to claim 8 wherein said water content is 5 to 30% by weight.
Claim 27
Dependent Claim
52 words
A method according to claim 24 wherein the water content in the solvent is 5 to 30% by weight and the saponification is carried out for 2 to 10 hours, the saponfication being carried out at first at 20° to 30° C. and then at a higher temperature up to 80° C.
Claim 28
Dependent Claim
52 words
A method according to claim 23 wherein the water content in the solvent is 5 to 30% by weight and the saponification is carried out for 2 to 10 hours, the saponification being carried out at first at 20° to 30° C. and then at a higher temperature up to 80° C.
Claim 29
Dependent Claim
52 words
A method according to claim 8 wherein the water content in the solvent is 5 to 30% by weight and the saponification is carried out for 2 to 10 hours, the saponification being carried out at first at 20° to 30° C. and then at a higher temperature up to 80° C.
Claim 30
Dependent Claim
52 words
A method according to claim 1 wherein the water content in the solvent is 5 to 30% by weight and the saponification is carried out for 2 to 10 hours, the saponification being carried out at first at 20° to 30° C. and then at a higher temperature up to 80° C.
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) | 1982-05-21 | 1982-11-20 | 1983-05-22 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1986-05-21 | 1986-11-20 | 1987-05-22 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1990-05-21 | 1990-11-20 | 1991-05-22 | $7700.00 | Window Closed / Lapsed |