Dispersal Of Ultra-fine Ground Calcium Carbonate And Its Application In Natural Latex

Ultra-fine ground calcium carbonate is a commonly used inorganic filler. It has been widely adopted for industrial use, such as the manufacture of plastic, rubber, coating and papermaking. Because ultra-fine ground calcium carbonate particles have a larger specific surface area and a higher specific surface energy, there is an existence of problem of particles aggregation, which prevents it from being directly used with effectiveness. For this reason, processing of its particle surface before application is required to improve its dispersibility.During the recent years, it is observed that the price of natural rubber has kept increasing, which in turn causes the cost of rubber products to being higher increase. Calcium carbonate is therefore introduced as an inorganic filler because of its sufficient resource, cheap price, and toxin-free nature. It would effectively reduce manufactural costs to use calcium carbonate as filler into rubber products. Among the researches of calcium carbonate, to solve its dispersibility in the media with low viscosity has been a major topic. As both water and natural rubber emulsion are the media with low viscosity, to solve ultra-fine ground calcium carbonate's dispersal problem in water would probably also solve the same problem in natural rubber. With this method, evenly dispersed ultra-fine ground calcium carbonate in natural rubber could be obtained.This thesis experimented the dispersal of ultra-fine ground calcium carbonate using dispersant of low molecular weight (NaPO3)6 and CH3(CH2)11SO4Na, poly- dispersant H34, H800, P998 and Y401, under high speed milling, and then discussed the impacts of different portions of dispersant in the experiment. The effectiveness of dispersal was represented and proved by the size distribution of ultra-fine ground calcium carbonate after being dispersed, Zeta potential, and the slurry viscosity of ultra-fine ground calcium carbonate. At last, sedimentation experiments are used to find out the best dispersant in term of the stability of particles of Ultra-fine ground calcium carbonate.