Silicone oils with improved viscosity stability
AssigneeDow Corning Corporation
InventorsRagnar Richard Avery, Jeffrey Scott Baker, Gerald Anthony Beeler, Michael Henry Brown, Kevin James Okeson
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Abstract
Silicone organic blends for use as lubricating oils, hydraulic fluids, dielectric fluids, coolants, and in compressor or vacuum pump applications, have improved viscosity stability when the polydispersity of the silicone fluids used in these blends, i.e., their molecular weight distribution (Mw/Mn), exceeds 1.5. The viscosity rise of the silicone organic blend is less than one centistoke (mm2/s) when aged 14 days in an oven at 100° C., compared to viscosity rises of about 1.3 to over 3.5 centistokes (mm2/s) for commercial silicone organic blends using silicone fluids with polydispersity less than 1.5.
Claims14
A composition comprising a blend of (A) at least about 85 percent by weight of a polysiloxane having a viscosity of 20-100 mm2/s at 25° C. as determined by ASTM D 445-94;
- (B) 1.5-5.0 percent by weight of a polysiloxane having a viscosity of 200-30,000 mm2/s at 25° C. as determined by ASTM D 445-94;
- the polydispersity of the blend of polysiloxane (A) and polysiloxane (B) having a value which exceeds 1.5 as determined at 25° C. by Gel Permeation Chromatography;
- and the remainder of the composition to 100 percent being (C) an additive comprising a lubricity improving agent, an antifoam agent, and a corrosion inhibiting agent;
- the viscosity rise of the composition being less than one mm2/s when aged 14 days in an oven at 100° C., as determined by ASTM D 445-94;
- polysiloxanes (A) and (B) having the structure:
- where n has a value to provide polysiloxanes (A) and (B) with a viscosity in the range of 20-100 mm2/s and 200-30,000 mm2/s at 25° C. respectively:
- and R1 and R2 are alkyl radicals of 1-6 carbon atoms.
A composition comprising a blend of (A) at least about 85 percent by weight of a polysiloxane having a viscosity of 20-100 mm2/s at 25° C. as determined by ASTM D 445-94;
- (B) 1.5-5.0 percent by weight of a polysiloxane having a viscosity of 200-30,000 mm2/s at 25° C. as determined by ASTM D 445-94;
- the polydispersity of the blend of polysiloxane (A) and polysiloxane (B) having a value which exceeds 1.5 as determined at 25° C. by Gel Permeation Chromatography;
- and the remainder of the composition to 100 percent being (C) an additive comprising a lubricity improving agent, an antifoam agent, and a corrosion inhibiting agent;
- the viscosity rise of the composition being less than one mm2/s when aged 14 days in an oven at 100° C., as determined by ASTM D 445-94;
- polysiloxanes (A) and (B) having the structure:
- where n has a value to provide polysiloxanes (A) and (B) with a viscosity in the range of 20-100 mm2/s and 200-30,000 mm2/s at 25° C. respectively;
- and R1 and R2 are alkyl radicals of 1-6 carbon atoms;
- the composition having a viscosity of 20-250 mm2/s at 25° C.
Dependencies are inferred from the claim text.