formvorrichtung to manufacture mikroporoeser kautschukgegenstaende, especially batterietrennwaende (diaphragms)

摘要

Articles of vulcanized rubber having microscopically small pores are prepared from aqueous dispersions of rubber and the like from which electrolytes which tend to produce gelling under hot or cold conditions are excluded, by coagulating or gelling such dispersions by any one or more of the usual operations of dipping, spreading, &c., and then vulcanizing the product under such conditions that the evaporation of liquid contained in the pores is prevented. The amount of dispersion medium contained in the pores is governed by the concentration of the latex mix before coagulation except in the case of electrodeposition when the alkalinity and conductivity of the mix are the controlling factors. Examples: A usual rubber mix is electrolyzed using zinc anodes and a current density of 0,6 amps. per sq. decimetre. Firmly coagulated deposits are obtained which are then vulcanized as described above. In a second example a usual mix was gelled by acid-free formaldehyde and the product vulcanized as in Example 1. Specifications 219,635 and 290,313, [both in Class 70, Indiarubber &c.], are referred to.