Silicone Oils

Silicone fluids are linear polysiloxanes: a flexible Si–O backbone with methyl groups on silicon, sometimes replaced by phenyl, trifluoropropyl, vinyl, hydrogen or hydroxyl. The backbone gives them a wide service temperature range, low surface tension, good dielectric properties and little change of viscosity with temperature. The groups on the chain, and at its ends, decide what else a fluid can do — whether it stays inert or takes part in a cure.

Types of silicone fluid

Dimethyl silicone fluid

Polydimethylsiloxane (PDMS) is the inert, general-purpose fluid: lubricant, release agent, damping and dielectric fluid, heat-transfer medium, and a base for antifoams.

• SF-200 Dimethyl silicone fluid

Hydroxyl-terminated fluids

Silanol ends react with alkoxy, acetoxy and oxime crosslinkers, so OH-terminated PDMS is the base polymer of condensation-cure (RTV) silicone sealants and rubbers. Low-viscosity silanol fluids also act as structure-control agents when fillers are compounded into silicone rubber.

• SF-QT200 OH end-blocked polydimethylsiloxane
• SF-MOH200 Silanol-functionalized fluid

Vinyl fluids

Vinyl groups react with Si–H in platinum-catalysed hydrosilylation, the chemistry of addition-cure silicones. Vinyl-terminated fluids build the network; mono-terminated fluids end chains and soften it.

• SF-VS200 Vinyl terminated silicone oil
• SF-MV200 Mono terminated vinyl silicone oil

Hydrogen fluids

Methylhydrogen fluids are the crosslinkers of addition-cure systems, paired with vinyl polymers. The same Si–H reactivity is used to make surfaces water-repellent and to graft organic groups onto silicone.

• SF-LH200 Side-containing hydrogen silicone oil
• SF-LH201 Hydrogen silicone oil

Phenyl fluids

Replacing some methyl groups with phenyl raises heat and oxidation resistance, radiation resistance and refractive index. Phenyl fluids serve as high-temperature heat-transfer and dielectric fluids and, at very low vapour pressure, as diffusion pump oils.

• SF305 Phenyl silicone oil
• SF752 Phenyl methyl silicone oil
• SF-H705 Trimethyl pentaphenyl trisiloxane
• SF704 Silicone Diffusion Pump Oil
• SF705 Silicone Diffusion Pump Oil

Fluorosilicone fluids

Trifluoropropyl groups make a silicone resistant to fuels, oils and non-polar solvents. The end groups again decide the role: methyl-terminated fluids are inert lubricants and release agents; hydroxyl, vinyl and hydrogen grades are reactive components of fluorosilicone rubber.

• SF-MF200 Methyl-terminated fluorosilicone oil
• SF-MF201 Fluoro silicone oil
• SF-OF200 Hydroxyl-terminated fluorosilicone oil
• SF-VF200 Vinyl fluoro silicone oil
• SF-HF201 Hydrogen-containing Fluorosilicone Fluid

How to choose a silicone fluid

• Inert or reactive. For lubrication, release, damping or heat transfer, use a non-reactive fluid. For a curing system, match the end or side group to the cure: silanol for condensation, vinyl and hydrogen for addition.
• Viscosity. It follows chain length. Low viscosity spreads and penetrates; high viscosity gives body, damping and film strength. Base polymers are chosen by the viscosity the uncured product needs.
• Temperature and chemicals. Choose phenyl for the highest temperatures and radiation, and fluorosilicone where fuels, oils or solvents are present.

For viscosity grades, a COA or an SDS, contact our sales team.