Method for hydrophilizing absorbent foam materials
First Claim
1. A method for rendering substantially hydrophobic polymeric foam material suitable for absorbing hydrophilic liquids, which method comprisesA) incorporating into a substantially hydrophobic polymeric foam material a substantially water-insoluble surfactant selected from the group consisting of sorbitan fatty acid esters, polyglycerol fatty acid esters and polyoxyethylene fatty acids and esters polyglycerol fatty acid esters and polyoxyethylene fatty acids and esters and a hydrophilizing salt solution formed from a solvent and a dissolved hydrophilizing salt selected from the group consisting of toxicologically acceptable, hydrated or hydratable calcium and magnesium slats;
- andB) thereafter drying said polymeric foam material to remove solvent therefrom and to thereby leave incorporated within said polymeric foam material a hydrophilizing amount of said surfactant and said hydrophilizing salt.
1 Assignment
0 Petitions
Accused Products
Abstract
Normally hydrophobic foams, such as polyurethane foams and polymerized water-in-oil emulsion foams, are rendered hydrophilic by means of treatment with simple surfactants and hydrophilizing agent salts. Thus, a surfactant-containing foam is treated with a solution of, for example, calcium chloride, and is dried to leave a substantially uniformly distributed residue of hydrated or hydratable calcium chloride on the surfactant-containing internal foam surfaces. In-use, the combination of surfactant and calcium chloride hydrate provides a hydrophilic surface to the foam. Other hydratable calcium or magnesium salts such as magnesium chloride can be used. The resulting hydrophilized foams are suitable for use in absorbent devices, including diapers, sanitary napkins, bandages, and the like.
76 Citations
20 Claims
-
1. A method for rendering substantially hydrophobic polymeric foam material suitable for absorbing hydrophilic liquids, which method comprises
A) incorporating into a substantially hydrophobic polymeric foam material a substantially water-insoluble surfactant selected from the group consisting of sorbitan fatty acid esters, polyglycerol fatty acid esters and polyoxyethylene fatty acids and esters polyglycerol fatty acid esters and polyoxyethylene fatty acids and esters and a hydrophilizing salt solution formed from a solvent and a dissolved hydrophilizing salt selected from the group consisting of toxicologically acceptable, hydrated or hydratable calcium and magnesium slats; - and
B) thereafter drying said polymeric foam material to remove solvent therefrom and to thereby leave incorporated within said polymeric foam material a hydrophilizing amount of said surfactant and said hydrophilizing salt. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9)
- and
-
10. A method for rendering substantially hydrophobic polymeric foam material suitable for absorbing hydrophilic liquids, which method comprises
A) incorporating an aqueous solution containing from about 1% to 10% by weight of calcium chloride in water into a polymeric foam material prepared by polymerizing a water-in-oil emulsion containing polymerizable monomers and from about 0.5% to 20% by weight of the polymerizable monomers of a surfactant selected from the group consisting of sorbitan monolaurate and mixtures of sorbitan monooleate and sorbitan trioleate in the oil phase of said emulsion; - and
B) thereafter drying said polymeric foam material to remove water therefrom and to leave incorporated within said foam material at least about 0.05% by weight of said foam material of surfactant plus calcium chloride and no more than about 50% by weight of said foam material of free water. - View Dependent Claims (11, 12)
- and
-
13. A hydrophilized polymeric foam material suitable for absorbing hydrophilic liquids, said hydrophilized polymeric foam material comprising a substantially hydrophobic polymeric foam material;
- a hydrophilizing amount of at least about 0.05% by weight of said polymeric foam material of the combination of a substantially water-insoluble surfactant selected from the group consisting of sorbitan fatty acid esters, polyglycerol fatty acid esters and polyoxyethylene fatty acids and esters and a hydrophilizing salt selected from the group consisting of toxicologically acceptable, hydrated or hydratable calcium and magnesium salts, incorporated into aid polymeric foam material; and
no more than about 50% by weight of said polymeric foam material of free water incorporated within said polymeric foam material. - View Dependent Claims (14, 15, 16, 17, 18, 19, 20)
- a hydrophilizing amount of at least about 0.05% by weight of said polymeric foam material of the combination of a substantially water-insoluble surfactant selected from the group consisting of sorbitan fatty acid esters, polyglycerol fatty acid esters and polyoxyethylene fatty acids and esters and a hydrophilizing salt selected from the group consisting of toxicologically acceptable, hydrated or hydratable calcium and magnesium salts, incorporated into aid polymeric foam material; and
Specification