| abstract |
The process for making goods of sponge rubber described in the parent Specification is modified to avoid the formation of surface skins on the finished articles, by causing a frothy mass of the aqueous dispersions to set with the exception of the outer layer, (i) by dipping a former into a coagulant, then into a froth of latex mixing, and washing away the outer surface of the deposit with water or dilute alkali before the coagulant has penetrated to the outer surface; (ii) by dipping a former into a heat sensitive latex froth, then into a non-heat sensitive latex froth, heating the former, and washing away the non-coagulated outer layer; (iii) by dipping a former into a latex froth, and then treating with a coagulating and swelling medium such as described in Specification 324,988, [Class 70, Indiarubber &c.]. Specification 219,635 and 290,313, [Class 70, Indiarubber &c.], also are referred to. |