Liquid silicone rubber (LSR) is mainly processed by liquid injection molding (LIM) because the material is particularly suitable for this purpose due to its low viscosity during processing. The density of the vulcanizate is about 1.1 g/cm3. With the aid of foamed silicones, density reductions of 0.5 g/cm3 to 1.0 g/cm3 can be achieved. This reduces the material requirement and consequently also the price. In addition, the insulation behavior against heat and cold as well as the floatability can be positively influenced. The floatability is decisive for separation processes in the recycling of materials. In this study, the positive effect of expandable thermoplastic microspheres as blowing agents in LSR will be illustrated.