Abstract: High amounts of silicon dioxide are readily incorporated into an emulsion polymerized elastomer by mixing an aqueous dispersion of silicon dioxide with a latex of the emulsion polymer and subsequently spray drying the mixture. Free flowing, fine-size (e.g., less than 500 micrometers) particles are produced with generally complete incorporation of silicon dioxide. The presence of the silicon dioxide permits rubbers with low gel and/or low Mooney viscosity to be spray dried whereas previously this could not be accomplished. Compared to conventional means of adding a silica to a bale rubber, the above powdered masterbatch gives shorter mixing times with lower power consumption with improved physical properties, such as tensile strength.

Abstract: High amounts of silicon dioxide are readily incorporated into an emulsion polymerized elastomer by mixing an aqueous dispersion of silicon dioxide with a latex of the emulsion polymer and subsequently spray drying the mixture. Free flowing, fine-size (e.g., less than 500 micrometers) particles are produced with generally complete incorporation of silicon dioxide. The presence of the silicon dioxide permits rubbers with low gel and/or low Mooney viscosity to be spray dried whereas previously this could not be accomplished. Compared to conventional means of adding a silica to a bale rubber, the above powdered masterbatch gives shorter mixing times with lower power consumption with improved physical properties, such as tensile strength.

Abstract: A no-post-cure method of curing polyacrylates having dual cure sites is accomplished with a two-part curing system or a combined one-part curing system. The two-part curing system consists of one of more metallic acid salts and an ammonium and/or phosphonium quaternary salt. The one-part curing system consists of an ammonium or phosphonium quaternary acid salt. The polyacrylate rubber must have both a halogen and a carboxyl cure site. The method consists of blending the curative with the polyacrylate rubber and heating the resultant composition until the composition cures. Because the mixed composition is shelf stable, it is not necessary to immediately heat the composition to cure it. The method may optionally include the step of storing the mixed composition until it is desired to cure it.