| abstract |
A method of reducing thixotropy of ammoniated latex concentrates, by the addition of proteolytic enzymes under alkaline conditions to the latex concentrate. The method is effective for both high and low ammonia latex concentrates. The reduction of viscosity includes the reduction of the Brookfield viscosity of the latex concentrate. The proteolytic enzyme used is pepsin, including papain. Preferably, the concentration of proteolytic enzyme used is in the range of from about 0.005 to 0.20% based on dry rubber content (DRC). Potassium hydroxide (KOH) may preferably be used to effectively remedy any adverse effects of the enzyme on the latex concentrate's properties, including chemical stability time (CST), mechanical stability time (MST), volatile fatty acid (VFA) number, and filterability. |