Patent US4880886A successfully refreshed from Google Patents.
US4880886A
Expired / Lapsed
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Process for production of highly water-absorbent resin
Assignee: Mitsubishi Chemical Corp
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Filing: 1988-06-27
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Granted: 1989-11-14
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Expires: 2008-06-27
Abstract
Abstract In a process for producing a highly water-absorbent resin comprising subjecting a mixture of (meth)acrylic acid with a water-soluble salt thereof as a monomer to reversed phase suspension polymerization in a hydrophobic solvent in the presence of a dispersing agent, improvements that at least a portion of said monomer is fed sequentially with the progress of polymerization reaction and at least a portion of said dispersing agent is fed sequentially with the progress of polymerization. The resulting resin is useful as a highly water-soluble resin component of sanitary products, or as a humectant/desiccant, a rheology modifier and so on.
Inventors
- 👤 Susumu Kondo
- 👤 Tetsuo Moriya
- 👤 Hiroshi Aoyama
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-08 11:45
CPC Classifications
C; C08; C08F; C08F2/00; C08F2/32
Claims Analysis
Total Claims: 6
Claim 1
Independent Claim
166 words
In a process for producing a highly waterabsorbent resin comprising subjecting a mixture of (meth)acrylic acid with a water-soluble salt thereof as a monomer to reversed phase suspension polymerization in a hydrophobic solvent in the presence of a dispersing agent, the improvement wherein at least a portion of said monomer is fed sequentially with the progress of the polymerization reaction and at least a portion of said dispersing agent is fed sequentially with the progress of polymerization, and wherein the polymerization reaction is conducted under the following parameter settings: Mi/Ma=0/100 to 20/80 Di/Da=0/100 to 40/60 D/M=1/100 to 6/100 Di/S=0/100 to 0.03/100 wherein M represents the total charge of monomer, Mi represents the initial charge of the monomer, Ma represents the additional charge of the monomer, D represents the total charge of the dispersing agent, Di represents the initial charge of the dispersing agent, Da represents the additional charge of the dispersing agent, and S represents the charge of the hydrophobic medium, all proportions being by weight.
Claim 2
Dependent Claim
166 words
In a process for producing a highly waterabsorbent resin comprising subjecting a mixture of (meth)acrylic acid with a water-soluble salt thereof as a monomer to reversed phase suspension polymerization in a hydrophobic solvent in the presence of a dispersing agent, the improvement wherein at least a portion of said monomer is fed sequentially with the progress of the polymerization reaction and at least a portion of said dispersing agent is fed sequentially with the progress of polymerization, and wherein the polymerization reaction is conducted under the following parameter settings: Mi/Ma=0/100 to 20/80 Di/Da=0/100 to 40/60 D/M=1/100 to 6/100 Di/S=0/100 to 0.03/100 wherein M represents the total charge of monomer, Mi represents the initial charge of the monomer, Ma represents the additional charge of the monomer, D represents the total charge of the dispersing agent, Di represents the initial charge of the dispersing agent, Da represents the additional charge of the dispersing agent, and S represents the charge of the hydrophobic medium, all proportions being by weight.
Claim 3
Dependent Claim
18 words
The improved process of claim 1 wherein Mi/Ma is 0/100 to 10/90 and Di/Da is 1/99 to 30/70.
Claim 4
Dependent Claim
19 words
The improved process of claim 1 wherein the additional charges of the monomer and dispersing agent are fed dropwise.
Claim 5
Dependent Claim
22 words
The improved process of claim 1 wherein the dispersing agent is a nonionic surfactant with an HLB value between 3 and 12.
Claim 6
Dependent Claim
30 words
The improved process of claim 6 wherein said nonionic surfactant with an HLB value between 3 and 12 is a sorbitan fatty acid ester or a sucrose fatty acid ester.
References Cited (Backward Citations)
JPS5832607A
Cited
US4654039A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1992-11-13 | 1993-05-15 | 1993-11-14 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1996-11-13 | 1997-05-15 | 1997-11-14 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2000-11-13 | 2001-05-15 | 2001-11-14 | $7700.00 | Window Closed / Lapsed |