Pituitous silicone fluids
View Patent ↗Fluid compositions are disclosed containing a branched organopolysiloxane and a carrier fluid. The branched organopolysiloxane is obtainable by reacting an organohydrogencyclosiloxane and an alkenyl terminated polydiorganosiloxane. The disclosed fluid compositions possess pituitous rheological properties.
1. A fluid composition comprising:
A) 0.1 to 10 wt % of a branched organopolysiloxane prepared by reacting;
a) an organohydrogencyclosiloxane having the formula [(CH 3 )HSiO] g where g is 3 to 8, and,
b) an alkenyl terminated polydiorganosiloxane comprising siloxy units of the formula (R 2 R 2 SiO 1/2 ) v (R 2 SiO 2/2 ) x
where v≧2, and x≧50,
R is an alkyl group containing 1 to 6 carbon atoms,
R 2 is an alkenyl group containing 2 to 12 carbon atoms,
in the presence of a hydrosilylation catalyst, where the molar ratio of alkenyl groups to SiH in the reaction is between 0.9/1 to 2.2/1, and
B) 90 to 99.9 wt % of a carrier fluid
selected from isododecane, isohexadecane, or isoparaffin, wherein the fluid composition has a viscosity of at least 300 mPa·s at 23° C. and exhibits pituitous rheological properties.
2. The fluid composition of claim 1 wherein the rheological properties of the fluid are determined from a plot of normal force in Pascals vs a perpendicular shear rate in sec −1 wherein the plot has an average slope that is greater than 3.6.
3. The fluid composition of claim 2 where the alkenyl terminated polydiorganosiloxane is a vinyl terminated polydimethylsiloxane.
4. The fluid composition of claim 3 wherein the vinyl terminated polydimethylsiloxane is a gum.
5. The fluid composition of claim 1 where g is 4.