US4842927A
Expired / Lapsed
US
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Process for preparation of water absorptive composite
Assignee: Mitsubishi Chemical Corp
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Filing: 1988-05-26
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Granted: 1989-06-27
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Expires: 2008-05-26
Abstract
Abstract A process for preparing a water absorptive composite consisting of a highly water absorptive polymer and a prefabricated fibrous substrate, which comprises applying an aqueous solution containing (a) a polymerizable monomer comprising as a main component acrylic acid, of which 20% or more of the carboxyl groups have been neutralized to its alkali metal salt or ammonium salt, (b) 2-vinylpyridine or(and) 4-vinylpyridine or(and) their salts, (c) a crosslinking agent and (d) an oxidative radical polymerization initiator to a prefabricated fibrous substrate, and then carrying out polymerization with addition of a reducing agent.
Inventors
- 👤 Kiichi Itoh
- 👤 Takeshi Shibano
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-04 06:34
CPC Classifications
C; C08; C08F; C08F220/00; C08F220/02; C08F220/04; D; D06; D06M; D06M14/00; D06M14/08; D06M14/12; D06M14/14; C08F2/00; D06M14/02; D06M14/04; D06M15/00; D06M15/19; D06M15/21; D06M15/263; Y; Y10; Y10T; Y10T428/00; Y10T428/31504; Y10T428/31855; Y10T428/3188; Y10T428/31895; Y10T428/31906; Y10T442/00; Y10T442/30; Y10T442/3325; Y10T442/40; Y10T442/469; Y10T442/60; Y10T442/647
Claims Analysis
Total Claims: 21
Claim 1
Independent Claim
95 words
A process for preparing a water absorptive composite consisting of a highly water absorptive polymer and a prefabricated fibrous substrate, which comprises applying an aqueous solution containing effective amounts of (a) a polymerizable monomer comprising as a main component acrylic acid, of which 20% or more of the carboxyl groups have been neutralized to its alkali metal salt or ammonium salt, (b) 2-vinylpyridine or(and) 4-vinylpyridine or(and) their salts, (c) a crosslinking agent and (d) an oxidative radical polymerization initiator to a prefabricated fibrous substrate, and then carrying out polymerization with addition of a reducing agent.
Claim 2
Dependent Claim
95 words
A process for preparing a water absorptive composite consisting of a highly water absorptive polymer and a prefabricated fibrous substrate, which comprises applying an aqueous solution containing effective amounts of (a) a polymerizable monomer comprising as a main component acrylic acid, of which 20% or more of the carboxyl groups have been neutralized to its alkali metal salt or ammonium salt, (b) 2-vinylpyridine or(and) 4-vinylpyridine or(and) their salts, (c) a crosslinking agent and (d) an oxidative radical polymerization initiator to a prefabricated fibrous substrate, and then carrying out polymerization with addition of a reducing agent.
Claim 3
Dependent Claim
34 words
The process according to claim 1, wherein the amount of the vinylpyridine monomer (b) used is 0.001 to 20 mol % based on the total amount of the same and the acrylic monomer (a).
Claim 4
Dependent Claim
15 words
The process according to claim 2, wherein said amount is 0.01 to 5 mol %.
Claim 5
Dependent Claim
79 words
The process according to claim 1, wherein the aqueous solution further contains an additional monomer selected from the group consisting of (a) methacrylic acid, itaconic acid, maleic acid, fumaric acid, 2-acrylamide-2-methylpropanesulfonic acid, 2-acryloylethanesulfonic acid, 2-acryloylpropanesulfonic acid and the salts thereof, (b) an alkyl or alkoxy ester of a dicarboxylic acid selected from itaconic acid, maleic acid and fumaric acid, (c) vinylsulfonic acid, (d) methyl acrylate and ethyl acrylate, (e) hydroxyethyl (meth)acrylate and hydroxypropyl (meth)acrylate and (f) polyethylene glycol mono(meth)acrylate.
Claim 6
Dependent Claim
23 words
The process according to claim 1, wherein the acrylic monomer (a) is one which has been neutralized with sodium hydroxide or potassium hydroxide.
Claim 7
Dependent Claim
19 words
The process according to claim 1, wherein the aqueous solution has a concentration of 20% by weight or more.
Claim 8
Dependent Claim
37 words
The process according to claim 1, wherein the crosslinking agent (c) is one which has two or more double bonds in the molecule and is copolymerizable with the acrylic monomer (a) and (or) the vinylpyridine monomer (b).
Claim 9
Dependent Claim
26 words
The process according to claim 1, wherein the oxidative radical polymerization initiator (c) and the reducing agent are those which can form a redox system therebetween.
Claim 10
Dependent Claim
39 words
The process according to claim 8, wherein the oxidative radical polymerization initiator (c) is selected from the group consisting of (a) a peroxide selected from hydrogen peroxide, persulfates and hydroperoxides and (b) secondary cerium salts, permanganates, chlorites, and hypochlorites.
Claim 11
Dependent Claim
34 words
The process according to claim 8, wherein the reducing agent is selected from the group consisting of sulfites, sodium thiosulfate, cobalt acetate, cupric sulfate, ferrous sulfate, L-ascorbic acid and L-ascorbic acid alkali metal salts.
Claim 12
Dependent Claim
28 words
The process according to claim 8, wherein the oxidative radical polymerization initiator is hydrogen peroxide and the reducing agent is L-ascorbic acid or its alkali metal salt. PG,26
Claim 13
Dependent Claim
34 words
The process according to claim 1, wherein the fibrous substrate is a pad of loose fabric, a carded web, an air-laid web, a paper, a nonwoven fabric, a woven fabric or a knitted fabric.
Claim 14
Dependent Claim
20 words
The process according to claim 1, wherein the fibrous substrate comprises as a main component cellulose fibers or polyester fibers.
Claim 15
Dependent Claim
25 words
The process according to claim 1, wherein the aqueous solution is applied to form dotted or linear patterns at periodic intervals on the fibrous substrate.
Claim 16
Dependent Claim
19 words
The process according to claim 1, wherein the reducing agent is applied through a spray nozzle in atomized form.
Claim 17
Dependent Claim
29 words
The process according to claim 1, wherein the temperature of the aqueous solution is maintained at 20° to 60° C. while it is being applied to the fibrous substrate.
Claim 18
Dependent Claim
18 words
The process according to claim 1, wherein the polymerization is carried out at room temperature to 60° C.
Claim 19
Dependent Claim
17 words
The process according to claim 17, wherein the polymerization temperature is from room temperature to 40° C.
Claim 20
Dependent Claim
18 words
The process according to claim 1, wherein the polymerization is carried out for several seconds to ten minutes.
Claim 21
Dependent Claim
12 words
A water absorptive composite produced by the process according to claim 1.
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) | 1992-06-26 | 1992-12-26 | 1993-06-27 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1996-06-26 | 1996-12-26 | 1997-06-27 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2000-06-26 | 2000-12-26 | 2001-06-27 | $7700.00 | Window Closed / Lapsed |