Improvements in the manufacture of rubber

High-grade indiarubber in the form of discrete shreds is obtained from skim latex by treating the skim with soap, e.g. an alkali metal soap such as sodium laurate or palmitate or an ammonium salt of a fatty acid, coagulating the skim, preferably with magnesium chloride, reducing the coagulum to a finely divided state by milling, soaking the shreds so obtained first in acid, e.g. sulphuric acid, and then in an alkaline solution of a proteolytic enzyme, e.g. a solution of trypsin brought to a pH of 11-12 by addition of an aqueous solution of ammonia or sodium or potassium hydroxide, submitting the shreds to a second milling, washing, dusting with a lubricant, e.g. zinc or magnesium stearate, and drying.