| abstract |
The process for the production of a microporous hard or soft rubber vulcanisate of the parent Specification is modified in that the substance of high boiling point is an ammonium salt which is used without the addition of aqueous ammonia. In an example 1500 grams ammonium carbonate, 3500 grams kaolin, 3000 grams sulphur, vulcanization accelerator, are formed into a crumbly mass with 14 grams sodium silicate, mixed with 5 kg. premasticated rubber, formed into plates and vulcanized. |