Organic Fillers for Latex Products

Manufacturer: We are familiar with inorganic fillers (i.e., calcium carbonate and clay), but what are organic fillers? What do they do? We are thinking of evaluating organic fillers if we have more knowledge of them.

John Woon (Senior Latex Consultant): Organic fillers normally used in the latex industry are polymeric in nature. Some examples are MMA grafted NR latex, and high-styrene SBR latex.

For some high-styrene SBR latex added in NR latex compounds, the tensile strength initially increases marginally before dropping drastically as the amount of SBR increases. Needless to say, the elongation at break drops while the modulus and hardness increase. The main reason for using high-styrene SBR is to improve the tear strength of the latex products.

MMA grafted NR latex behaves quite similarly as high-styrene SBR latex.

The other advantage of organic fillers is that one can increase the modulus and stiffness of latex products without having to add inorganic fillers such as clay and calcium carbonate, and hence the tensile strength could be easier to maintain.