Polymethylsilsesquioxane

Polymethylsilsesquioxane (CAS 68554-70-1), also marketed as MSP-S and known in the silicone industry as Me silsesquioxane, is a spherical silicone resin powder used to modify surface texture.

It enhances optical properties and flow behavior across personal care and industrial formulations. Its crosslinked three-dimensional structure delivers performance that conventional silicone fluids or standard fillers cannot replicate.

In color cosmetics and skincare, it functions as a soft-focus agent and skin-feel modifier. It works by reducing shine, blurring imperfections, and improving spreadability in foundations, primers, and pressed powders.

Coating formulators incorporate it as a matting agent and anti-blocking additive in UV-cure, solvent-borne, and waterborne systems. It is essential where surface slip and scratch resistance are critical performance factors.

In adhesives and sealants, it adjusts rheology and reduces surface tack without compromising bond performance. Plastics compounders use it as a processing aid and surface modifier to improve scratch resistance.

It helps reduce the coefficient of friction in film and molded part applications. Polymethylsilsesquioxane is supplied as a fine white powder, with particle size distributions typically ranging from submicron to several microns.

Cosmetic-grade material is the most commercially prevalent, with technical grades available for industrial coating and polymer applications. Purity and particle size specifications vary by manufacturer.

These specifications should be confirmed against specific application requirements. The material remains a versatile choice for formulators seeking high-performance surface modification and tactile improvement.