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US 5,108,383 AGranted
Membranes for absorbent packets
AssigneeAllied-Signal Inc.
InventorLloyd S. White
Life of this patent
Estimating the term…
Abstract
An absorbent article comprising a cellulosic membrane about 5 to 50 .mu.m thick prepared by casting a film from solution of a cellulose derivative in a suitable solution and these formed into a packet which encapsulates an osmotic promoter, particularly sodium chloride, sugar or other suitable compound, preferably having a molecular weight below about 500. The packet is capable of taking up at least 0.001 g/cm.sup.2 /min of water and retaining it against an external pressure of at least 0.689 kPa.
Claims19
An absorbent article capable of absorbing water and retaining said water against an external pressure which comprises:
- (a) an osmotic promoter having a molecular weight below 1000;
- (b) a cellulosic membrane having reverse osmosis properties encapsulating said promoter having a thickness of about 5 to 50 .mu.m produced by the process of
- (1) casting a solution of a soluble cellulose derivative in at least one liquid selected from the group consisting of acetone, dimethylformamide, dimethylacetamide, dimethylsulfoxide, 1-methyl-2-pyrrolidone, formamide, dioxane, tetraethylphosphate, acetic acid, tetrahydrofuran, and water, onto a suitable surface,
- (2) removing the liquid from the film of (1),
- (3) annealing the film of (2) in water,
- (4) conditioning the annealed film of (3) in water containing a conditioning agent selected from the group consisting of glycerol, ethylene glycol, and propylene glycol,
- (5) drying the conditioned film of (4).
4 more elements
Dependencies are inferred from the claim text.