US4320040A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Method for preparing highly absorbent hydro-gel polymers
Assignee: Sumitomo Chemical Co Ltd
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Filing: 1980-06-18
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Granted: 1982-03-16
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Expires: 2000-06-18
Abstract
Abstract A method for producing a hydrophilic gel comprising polymerizing acrylic acid and/or methacrylic acid in the presence of polyvinyl alcohol to obtain a polymer (A) which is then subjected to neutralization followed by heat treatment or to heat treatment followed by neutralization, or polymerizing a neutralized product of acrylic acid and/or methacrylic acid in the presence of polyvinyl alcohol to obtain a polymer (B) which is then subjected to heat treatment, wherein said polymerization is carried out in an aqueous solution having a total concentration of acrylic acid and/or methacrylic acid or its neutralized product (the weight of the neutralized product is converted to the acid basis) and polyvinyl alcohol of 10 to 60% by weight, said heat treatment temperature is 50° to 150° C., and the weight ratio of polyvinylalcohol is acrylic acid and/or methacrylic acid or its salt (the weight of the neutralized product is converted to the acid basis) is 5 to 95: 95 to 5.
Inventors
- 👤 Fumio Fujita
- 👤 Shuji Kitamura
- 👤 Toshifumi Tamura
- 👤 Tsuneyuki Nagase
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-24 08:59
CPC Classifications
C; C08; C08F; C08F8/00; C08F8/44; A; A61; A61L; A61L15/00; A61L15/16; A61L15/42; A61L15/60; C08F20/00; C08F20/02; C08F20/04; C08F20/06; C08F261/00; C08F261/02; C08F261/04; C08F8/30; C08F8/32; Y; Y10; Y10S; Y10S524/00; Y10S524/916
Claims Analysis
Total Claims: 17
Claim 1
Independent Claim
158 words
A method for producing a hydrophilic gel comprising polymerizing acrylic acid and/or methacrylic acid in the presence of polyvinyl alcohol to obtain a polymer (A) which is then subjected to neutralization followed by heat treatment or to heat treatment followed by neutralization, or polymerizing a neutralized product of acrylic acid and/or methacrylic acid in the presence of polyvinyl alcohol to obtain a polymer (B) which is then subjected to heat treatment, wherein said polymerization is carried out in an aqueous solution having a total concentration of acrylic acid and/or methacrylic acid or its neutralized product (the weight of the neutralized product is converted to the acid basis) and polyvinyl alcohol of 10 to 60% by weight, said heat treatment temperature is 50° to 150° C., and the weight ratio of polyvinylalcohol to acrylic acid and/or methacrylic acid or its salt (the weight of the neutralized product is converted to the acid basis) is 10 to 90:90 to 10.
Claim 2
Independent Claim
158 words
A method for producing a hydrophilic gel comprising polymerizing acrylic acid and/or methacrylic acid in the presence of polyvinyl alcohol to obtain a polymer (A) which is then subjected to neutralization followed by heat treatment or to heat treatment followed by neutralization, or polymerizing a neutralized product of acrylic acid and/or methacrylic acid in the presence of polyvinyl alcohol to obtain a polymer (B) which is then subjected to heat treatment, wherein said polymerization is carried out in an aqueous solution having a total concentration of acrylic acid and/or methacrylic acid or its neutralized product (the weight of the neutralized product is converted to the acid basis) and polyvinyl alcohol of 10 to 60% by weight, said heat treatment temperature is 50° to 150° C., and the weight ratio of polyvinylalcohol to acrylic acid and/or methacrylic acid or its salt (the weight of the neutralized product is converted to the acid basis) is 10 to 90:90 to 10.
Claim 3
Dependent Claim
88 words
A method according to claim 1, wherein the carboxylic acid group of the neutralized product of the polymer (A), acrylic acid or methacrylic acid is represented by the formula, -COO.sup.- R.sub.1.sup.+ wherein R 1 is a sodium or potassium atom, ##STR3## (in which R 2 , R 3 , R 4 and R 5 are each hydrogen atom, C 1 -C 4 alkyl or alkanol group, phenyl group, C 7 -C 8 aralkyl or aryl group and at least one of them is a hydrogen atom) or ##STR4##
Claim 4
Dependent Claim
18 words
A method according to claim 2, wherein R 1 is a sodium or potassium atom or ammonium group.
Claim 5
Dependent Claim
13 words
A method according to claim 3, wherein R 1 is a sodium atom.
Claim 6
Dependent Claim
16 words
A method according to claim 1, wherein the weight ratio is 12 to 88:88 to 12.
Claim 7
Dependent Claim
16 words
A method according to claim 1, wherein the total concentration is 12 to 50% by weight.
Claim 8
Dependent Claim
17 words
A method according to claim 1, wherein the aqueous solution is dispersed in a water-insoluble organic solvent.
Claim 9
Dependent Claim
17 words
A method according to claim 1, wherein the temperature of heat treatment is 60° to 120° C.
Claim 10
Dependent Claim
30 words
A method according to claim 1, wherein said polymer (A) is neutralized with an alkali selected from the group consisting of sodium hydroxide, potassium hydroxide, ammonia and an organic amine.
Claim 11
Dependent Claim
18 words
A method according to claim 9, wherein the polymer (A) is neutralized with sodium hydroxide or potassium hydroxide.
Claim 12
Dependent Claim
53 words
A method according to claim 9, wherein the neutralization agent is an organic amine member selected from the group consisting of methylamine, dimethylamine, trimethylamine, ethylamine, diethylamine, triethylamine, n-propylamine, isopropylamine, di-n-propylamine, di-isopropylamine, tri-n-propylamine, tri-isopropylamine, tert-butylamine, n-butylamine, isobutylamine, di-tert-butylamine, d-n-butylamine, di-isobutylamine, tri-tert-butylamine, tri-isobutylamine, tri-n-butylamine, monoethanolamine, diethanolamine, triethanolamine, monoisopropanolamine, diisopropanolamine, triisopropanolamine, cyclohexylamine, benzylamine, aniline and pyridine.
Claim 13
Dependent Claim
46 words
A method according to claim 1, wherein the polymerization for obtaining said polymer (A), or said polymer (B) is carried out adding a crosslinking agent in amount of 0.0001 to 20 mole % based on the amount of acrylic acid and/or methacrylic acid, or its salt.
Claim 14
Dependent Claim
11 words
A hydrophilic gel obtained by the method according to claim 1.
Claim 15
Dependent Claim
10 words
A hydrophilic gel prepared by the method of claim 2.
Claim 16
Dependent Claim
10 words
A hydrophilic gel prepared by the method of claim 5.
Claim 17
Dependent Claim
10 words
A hydrophilic gel prepared by the process of claim 12.
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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) | 1985-03-15 | 1985-09-14 | 1986-03-16 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1989-03-15 | 1989-09-14 | 1990-03-16 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1993-03-15 | 1993-09-14 | 1994-03-16 | $7700.00 | Window Closed / Lapsed |