Silicone and plastics

Silicone polymers, typically used in vinyl & rubber "protectants", are not cleaners. They make the substrate to which they are applied shiny. That's it. The commonly used viscosities used to formulate the emulsions known as Armorall and the like, will not act as solvents. In order to have solvent-like activity you would have to use a silicone fluid lower in viscosity than 20 cst. Due to cost and the fact that no additional benefit is offered, no-one is using a viscosity < 50 cst.

However (there's always a "however"), Certain plastics will be stiffened and will craze upon exposure to common silicone fluids. But this is primarily due to the silicone causing the plasticizers in the plastic to leach out causing the plastic to become brittle, certainly not to "melt" and become gummy.

One basic fact is that silicone has a great affinity for silicone. Therefore, if a silicone fluid comes in contact with a surface that has been coated with a silicone resin, rubber, etc. it will be absorbed and make a "gummy" mess, but not cause "melting". If a supplier of automotive interior substrates is using a silicone for treating the surface, you would think they or the auto manufacturer would warn against using something as common as Armorall or similar products.

One last point, many professional detail shops, car washes, etc. use silicone tire dressings made with silicone fluid and a solvent such as mineral spirits. If something of this type, rather than a water-based emulsion such as Armorall, is used on the interior, you will most probably end up damaging some surfaces. But this is due to the solvent, not the silicone.

I sincerely hope that I managed to add to the confusion. <G>

Tom

 

If the plastic was of a type affected by silicone, The problem would show up fairly quickly. Additionally, were the plastic being attacked by the silicone the effect would be embrittlement and crazing. Fairly easy to see.

Tom