Self adhesive polyurethane foam gel contg. water absorber - with non-aq. foaming agents, useful as plasters, wound dressings, etc., adheres to skin but not to wet wounds

摘要

Self-adhesive, hydrophilic gel comprises: (i) a polyurethane gel contg.: (A) 15-62 (esp. 25-47) wt.% on (A) plus (B) of a covalently crosslinked polyurethane (high mol.wt. matrix); (B) 85-38 (esp. 75-53) wt.% polyhydroxy cpd. (I) firmly held in the matrix by sec. valency forces as liq. dispersion agent; and opt. (C) 0-100 wt.% on (A) plus (B) of fillers and/or additives; (ii) a water-absorbing material (II); and (iii) a non-aq. foaming agent (III). (I) has mean mol. wt. 1000-12000 (best 2000-6000) and mean OH no. 20-112 (esp. 28-56) and is free of OH cpds. of mol.wt. below 800 (esp. below 1500). The gel is made by reacting polyisocyanate (IV), (I), opt. catalyst, accelerator, filler and additives. The mean functionality (F1) of (IV) is 2-4 and that (F2) of (I) is 3-6, and the isocyanate characteristic no. K is 15-70. K is given by the formula K = ((300+/- X)/(F1-F2)-1)+7 (X is not over 120, esp. not over 90). USE/ADVANTAGE - The foams (esp. formed as layers on flat surfaces) are used as adhesive plasters, wound dressings, bandages, protective materials, compresses, etc., partic. for deep wounds (over which several thin layers of material can be applied). Compared with known compsns., these gels require less absorber, do not need additional release layers and can allow wide variations in adhesive/absorption properties.