Evaluation of the use of processing aids in silicone elastomers and cellular silicones

We evaluated two processing aids, UCC's Y1587 and GE's SE4210, in GE's SE54, type 97, and type 60 silicone gums. We tested uncured L1668 reinforced gums, cured L3219 elastomers, and L3223 and L3260 cellular silicones. In the new type 97KVB and type 60VB silicone gums, Y1587 produces a softer cushion than SE4210. The type of processing aid has no significant effect on uncured L1668 and has no effect on the compression set of the higher density L3223. For lower density L3260 cushions, Y1587 produces a significantly lower compression set than SE4210. If compression set is not a big consideration, or if cushion density is high, the choice of a processing aid can be used to control cushion stiffness along with the amount of reinforcing SiO/sub 2/, vinyl content, and porosity. Y1587 is preferred for all silicone gums, and it is important that it be used in the 97KVB and 60KVB gums. 55 tables.