Method of dispersing silicone compositions in organic thermoplastic materials

A method of dispersing silicone compositions in organic thermoplastic materials, the organic thermoplastic materials having a temperature-dependent complex viscosity, .eta.*.sub.OTP (T), associated therewith, the method comprising the steps of:

• (I) first blending the following components to substantial homogeneity:
• (A) an organosilicone resin of the empirical formula
• (R.sub.3 SiO.sub.1/2).sub.a (R.sub.2 SiO.sub.2/2).sub.b (RSiO.sub.3/2).sub.c (SiO.sub.4/2).sub.d
• wherein:
• a and d are positive numerical values and b and c are zero or positive numerical values with the provisos that a+b+c+d=1 and 0.ltoreq.(b+c).ltoreq.0.2 and R is a monovalent radical independently selected from the group consisting of hydrogen, hydroxyl, alkyl, alkenyl, alkoxy, oximo, aryl, epoxide, carboxyl, ether, polyether, amide and alkyl amino radicals, which R groups may be the same or different, with the proviso that at least sixty mole percent of said R radicals are methyl;
• said organosilicone resin (A) having a number average molecular weight (Mn) between about 2,000 and about 15,000;
• and
• (B) a predominantly linear silicone fluid having the empirical formula
• (R'.sub.3 SiO.sub.1/2).sub.x (R'.sub.2 SiO.sub.2/2).sub.y (R'SiO.sub.3/2).sub.z
• wherein:
• x and y are positive numerical values and z is 0 or a positive numerical value with the provisos that x+y+z=1 and y/(x+y+z).gtoreq.0.8;
• and R' is a monovalent radical independently selected from the group consisting of hydrogen, hydroxyl, alkyl, alkenyl, alkoxy, oximo, aryl, epoxide, carboxyl, ether, polyether, amide and alkyl amino radicals, which R' groups may be the same or different, with the proviso that at least sixty mole percent of said R' radicals are methyl;
• said predominantly linear silicone fluid (A) having a degree of polymerization greater than about 10;
• to form an organosilicone alloy therefrom;
• said organosilicone alloy having a temperature-dependent complex viscosity .eta.*.sub.Si (T) associated therewith;
• (II) then mixing said organosilicone alloy formed in step (I) with said organic thermoplastic material at a predetermined mixing temperature, T.sub.m and a predetermined shear strain rate;
• said organic thermoplastic material and silicone alloy being flowable at T.sub.m ;
• and
• said predetermined mixing temperature T.sub.m being about .+-.30.degree. C. of a temperature, T.sub.0, wherein the absolute value of {.eta.*.sub.OTP (T.sub.0)-.eta.*.sub.Si (T.sub.0)} is at its lowest value at said predetermined shear strain rate.