REGENERATED CELLULOSE SPONGE

1434643 Compressed regenerated cellulose sponges AVICON Inc 8 Oct 1973 [19 Oct 1972] 46954/73 Heading C3C [Also in Division B2] A compressed regenerated cellulose sponge is impregnated with and contains uniformly distributed throughout the sponge 0À15-5% by wt. of a water-soluble or -dispersible, high molecular weight, hydrophilic, film-forming polymer and has a bulk density of at least 112 kg./cu.m. The sponge is made by impregnating a regenerated cellulose sponge with an aqueous solution of dispersion of 0À005-0À250% by wt. of the polymer, drying the sponge to a moisture content of no more than 0À5% by wt. conditioning the dried sponge to a moisture content of at least 6% by wt. and then compressing the sponge. In the examples a regenerated cellulose sponge, e.g. made from a mixture of viscose, reinforcing fibres and a pore former, was washed with water, passed between rubber rollers to remove excess of water and then immersed in aqueous solution or dispersions of microcrystalline collagen (i.e. a partial acid salt of collagen) gelatin, polyvinyl alcohol, a hydroxypropylmethyl cellulose, starch, collagen fibrils or regenerated cellulose, excess water was removed and the sponge was then dried and compressed.