US4093776A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Process for preparation of spontaneously-crosslinked alkali metal acrylate polymers
Assignee: Kao Corp
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Filing: 1977-09-23
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Granted: 1978-06-06
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Expires: 1997-09-23
Abstract
Abstract Spontaneously cross-linked alkali metal acrylate polymers having a high water-absorbing property and which are safe for contact with the human skin are prepared by a water-in-oil suspension polymerization process, using a sorbitan fatty acid ester having an HLB value of 3 to 6 as a dispersing agent.
Inventors
- 👤 Shuzo Aoki
- 👤 Harumasa Yamasaki
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-23 17:18
CPC Classifications
C; C08; C08F; C08F120/00; C08F120/02; C08F120/04; C08F120/06; Y; Y10; Y10S; Y10S526/00; Y10S526/909; Y10T; Y10T428/00; Y10T428/29; Y10T428/2982
Claims Analysis
Total Claims: 8
Claim 1
Independent Claim
95 words
A process for the preparation of powdery, spontaneously crosslinked, alkali metal acrylate homopolymer having a water absorption capacity of at least 400 grams per one gram of dried polymer, said process comprising dispersing and suspending an aqueous solution of an alkali metal acrylate having a concentration of at least 40% by weight and containing a water-soluble radical polymerization initiator in a liquid aliphatic hydrocarbon solvent, in the presence of a sorbitan fatty acid ester having an HLB value of 3 to 6, and polymerizing the alkali metal acrylate in the absence of a crosslinking agent.
Claim 2
Dependent Claim
95 words
A process for the preparation of powdery, spontaneously crosslinked, alkali metal acrylate homopolymer having a water absorption capacity of at least 400 grams per one gram of dried polymer, said process comprising dispersing and suspending an aqueous solution of an alkali metal acrylate having a concentration of at least 40% by weight and containing a water-soluble radical polymerization initiator in a liquid aliphatic hydrocarbon solvent, in the presence of a sorbitan fatty acid ester having an HLB value of 3 to 6, and polymerizing the alkali metal acrylate in the absence of a crosslinking agent.
Claim 3
Dependent Claim
35 words
A process for the preparation of alkali metal acrylate polymer according to claim 1 wherein the alkali metal acrylate is one prepared by neutralizing 50 to 95% of acrylic acid with an alkali metal hydroxide.
Claim 4
Dependent Claim
22 words
A process for the preparation of alkali metal acrylate polymer according to claim 2 wherein the alkali metal hydroxide is sodium hydroxide.
Claim 5
Dependent Claim
23 words
A process for the preparation of alkali metal acrylate polymer according to claim 1 wherein the sorbitan fatty acid ester is sorbitan monostearate.
Claim 6
Dependent Claim
20 words
A process for the preparation of alkali metal acrylate polymer according to claim 1 wherein the aliphatic hydrocarbon is n-hexane.
Claim 7
Dependent Claim
102 words
A process for the preparation of alkali metal acrylate polymer according to claim 1 wherein an aqueous solution of an alkali metal acrylate having a concentration ranging from 40% by weight to the saturated concentration thereof in water, said solution containing potassium or ammonium persulfate in an amount of 0.01 to 1% by weight, based on the weight of the alkali metal acrylate monomer, is dispersed and suspended in n-hexane in the presence of sorbitan monostearate, the alkali metal acrylate monomer is polymerized in this state, and n-hexane and water are removed and the residue is dried to obtain a powdery polymer.
Claim 8
Dependent Claim
28 words
A powdery, crosslinked, alkali metal acrylate homopolymer prepared by the process of claim 1 and having a particle size in the range of from 0.01 to 0.12 mm.
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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) | 1981-06-05 | 1981-12-05 | 1982-06-06 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1985-06-05 | 1985-12-05 | 1986-06-06 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1989-06-05 | 1989-12-05 | 1990-06-06 | $7700.00 | Window Closed / Lapsed |