US4295987A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Cross-linked sodium polyacrylate absorbent
Assignee: Procter and Gamble Co
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Filing: 1979-12-26
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Granted: 1981-10-20
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Expires: 1999-12-26
Abstract
Abstract The present invention involves compositions of super absorbent polymers which absorb many times their weight in water and aqueous fluids. Super absorbent polymers in the prior art have effectively absorbed many times their weight of water, however, they become slimy to the touch or become so fluid as to migrate away from their point of application. The absorbent composition of the current invention absorbs substantial amounts of water without becoming slimy and migrating out from its applicator, as in absorbent articles. The absorbent composition of the current invention comprises a copolymer of acrylic acid cross-linked with a first cross-linking component comprising a monomer having at least two vinyl groups and a second cross-linking component comprising an ionic divalent cation. In the current invention, this composition can be mixed with cellulose fibers to enhance wicking. This composition is useful in absorbent articles and has proven to be particularly well suited to be incorporated between two plies of paper to make a two-ply paper towel.
Inventors
- 👤 Lawrence R. Parks
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-24 18:37
CPC Classifications
C; C08; C08F; C08F265/00; C08F265/02; A; A61; A61L; A61L15/00; A61L15/16; A61L15/42; A61L15/60; Y; Y10; Y10T; Y10T428/00; Y10T428/24; Y10T428/24355; Y10T428/24372; Y10T428/24405; Y10T428/249921; Y10T428/249953; Y10T428/249982; Y10T428/249984; Y10T428/26; Y10T428/269
Claims Analysis
Total Claims: 21
Claim 1
Independent Claim
34 words
An absorbent composition comprising a copolymer of acrylic acid cross-linked with a first cross-linking component comprising a monomer having at least two vinyl groups and a second cross-linking component comprising an ionic divalent cation.
Claim 2
Dependent Claim
34 words
An absorbent composition comprising a copolymer of acrylic acid cross-linked with a first cross-linking component comprising a monomer having at least two vinyl groups and a second cross-linking component comprising an ionic divalent cation.
Claim 3
Dependent Claim
14 words
The composition of claim 1 wherein the acrylic acid is neutralized with sodium hydroxide.
Claim 4
Dependent Claim
33 words
An absorbent composition having a formula of: ##STR3## where n is approximately 100-500; m is approximately 1-30; and A is selected from the group consisting of zinc, calcium, barium, strontium, or mixtures thereof.
Claim 5
Dependent Claim
33 words
An absorbent composition having a formula of: ##STR3## where n is approximately 100-500; m is approximately 1-30; and A is selected from the group consisting of zinc, calcium, barium, strontium, or mixtures thereof.
Claim 6
Dependent Claim
11 words
The composition of claim 1 additionally containing cellulose fibers mixed therewith.
Claim 7
Dependent Claim
37 words
The composition claimed in claims 1 or 3 wherein the copolymer contains up to 50% by weight of a fourth component selected from the group consisting of methacrylic acid, 2-hydroxyethyl methacrylate, acrylamide, acrylic esters and mixtures thereof.
Claim 8
Dependent Claim
28 words
The composition as claimed in claims 1 or 2 or 3 wherein the second cross-linking component is zinc and comprises 6 to 30% by weight of said composition.
Claim 9
Dependent Claim
18 words
The composition as claimed in claim 6 where zinc comprises 10 to 12% by weight of said composition.
Claim 10
Dependent Claim
26 words
The composition as claimed in claims 1 or 3 wherein the second cross-linking component is calcium and comprises 3 to 8 weight percent of said composition.
Claim 11
Dependent Claim
18 words
The composition as claimed in claim 8 wherein calcium comprises 6 to 7 weight percent of said composition.
Claim 12
Dependent Claim
24 words
The composition as claimed in claim 1 wherein said second cross-linking component is strontium and comprises 8 to 18 weight percent of said composition.
Claim 13
Dependent Claim
18 words
The composition as claimed in claim 10 wherein strontium comprises 10 to 16 weight percent of said composition.
Claim 14
Dependent Claim
25 words
The composition as claimed in claim 1 wherein said second cross-linking component is barium and comprises 12 to 28 percent by weight of the composition.
Claim 15
Dependent Claim
25 words
The composition as claimed in claim 12 wherein said second cross-linking component is barium and comprises 16 to 25 percent by weight of the composition.
Claim 16
Dependent Claim
18 words
The composition as claimed in claim 3 wherein A is a mixture of zinc, calcium, strontium and barium.
Claim 17
Dependent Claim
93 words
A process to make an absorbent polymeric composition comprising: supplying to a container means acrylic acid, a cross-linking monomer having at least two vinyl groups, potassium persulfate and water; forming a first mixture by mixing the contents of said container means in a nitrogen atmosphere at approximately 40°-80° C. for approximately one hour; maintaining said first mixture in the container means at 40°-80° C. for approximately two hours; neutralizing said first mixture to yield a second mixture; and adding ionic divalent cation to said second mixture and mixing to yield a third mixture.
Claim 18
Dependent Claim
93 words
A process to make an absorbent polymeric composition comprising: supplying to a container means acrylic acid, a cross-linking monomer having at least two vinyl groups, potassium persulfate and water; forming a first mixture by mixing the contents of said container means in a nitrogen atmosphere at approximately 40°-80° C. for approximately one hour; maintaining said first mixture in the container means at 40°-80° C. for approximately two hours; neutralizing said first mixture to yield a second mixture; and adding ionic divalent cation to said second mixture and mixing to yield a third mixture.
Claim 19
Dependent Claim
25 words
The process as claimed in claim 15 wherein the cross-linking monomer selected from the group consisting of tetraethylene glycol diacrylate, ethylene glycol diacrylate and diacrylamide.
Claim 20
Dependent Claim
25 words
The process claimed in claim 15 wherein the ionic divalent cation is selected from the group consisting of zinc, calcium, barium, strontium and mixtures thereof.
Claim 21
Dependent Claim
29 words
The process as claimed in claim 15 wherein said first mixture includes a second monomer selected from the group consisting of methacrylic acid, 2-hydroxyethyl methacrylate, acrylamide, and mixtures thereof.
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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) | 1984-10-19 | 1985-04-20 | 1985-10-20 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1988-10-19 | 1989-04-20 | 1989-10-20 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1992-10-19 | 1993-04-20 | 1993-10-20 | $7700.00 | Window Closed / Lapsed |