Films and absorbent articles made from copolymers having a copolymerized crosslinker
AssigneeThe Dow Chemical Company
InventorJames R. Gross
Life of this patent
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Abstract
Water swellable absorbent articles, made from copolymers having a copolymerized crosslinker, together with methods for their preparation, and a composition containing a copolymerized crosslinker useful to make said articles are disclosed. The copolymers comprise 25-98% by weight of an alkali metal salt of an olefinically unsaturated monosulfonic or monocarboxylic acid, about 2-50% by weight of an olefinically unsaturated monocarboxylic acid and about 0.1-5.0% by weight of an N-substituted acrylamide or methacrylamide. The articles are crosslinked by heating and/or removing substantialy all of the water from the precursor composition. The absorbent articles are useful as surgical sponges, diapers, tampons, meat trays, bath mats and the like.
Claims12
A substantially dry water swellable polyelectrolyte film prepared by the method which comprises
- 1. preparing a solution which comprises,
- I. a solvent selected from the group consisting of water, lower alcohols and mixtures thereof, and
- Ii. about 5 to about 60% by weight based on (I) of a crosslinkable carboxylic copolymer which contains in the copolymer
- A. about 25 to about 98% by weight based on the total weight of the copolymer of units derived from an alkali metal salt of an olefinically unsaturated monosulfonic or monocarboxylic acid;
- B. about 2 to about 50% by weight of units derived from an olefinically unsaturated monocarboxylic acid;
- and
- C. about 0.1 to about 5.0% by weight of units derived from an N-substituted acrylamide or methacrylamide having the formula
- H.sub.2 C=CR--C(O)--NHCH.sub.2 --O--R'
- wherein R is selected from hydrogen or methyl and R' is hydrogen or an alkyl group of 1-8 carbons,
- 2. spreading a coating of said solution on an impervious substrate,
- 3. heating said coated substrate to a temperature greater than about 30.degree. C to crosslink said polyelectrolyte and
- 4. separating said crosslinked polyelectrolyte film from said substrate.
An absorbent article coated with a substantially dry water swellable polyelectrolyte prepared by the method which comprises
- 1. preparing a solution which comprises,
- I. a solvent selected from the group consisting of water, lower alcohols and mixtures thereof, and
- Ii. about 5 to about 60% by weight based on (I) of a crosslinkable carboxylic copolymer which contains in the copolymer
- A. about 25 to about 98% by weight based on the total weight of the copolymer of units derived from an alkali metal salt of an olefinically unsaturated monosulfonic or monocarboxylic acid:
- B. about 2 to about 50% by weight of units derived from an olefinically unsaturated monocarboxylic acid;
- and
- C. about 0.1 to about 5.0% by weight of units derived from an N-substituted acrylamide or methacrylamide wherein the substitutent group is a hydroxy methylene or an alkoxymethylene group having 1-8 carbons,
- 2. applying a solution of said composition on a relatively thin article,
- 3. heating said coated article to a temperature greater than about 30.degree. C to crosslink said polyelectrolyte.
Dependencies are inferred from the claim text.