Method of melt blending curable polymer compositions using silicone hydrides

A method of melt blending comprising:

• (a) providing a screw-type extruder possessing addition points from a zero point to a 100 point the length of the extruder, where the extruder has an L/D of 42 and an output of 70 kg/hr;
• (b) adding polypropylene homopolymer and ethylene-propylene-diene rubber at the zero to 10 point of the extruder, where the rubber includes units deriving from 5-vinyl-2-norbornene;
• (c) melt blending the thermoplastic and the rubber at a temperature of from 180° C. to 290° C. and at a shear rate in the range of 2,000 to 8,000 s−1;
• (d) adding a silicone hydride at the 16 point of the extruder;
• (e) adding at least one metal catalyst at the 33 point of the extruder, where the silicone hydride has the formula:
• wherein H is hydrogen, and each R′ is methyl, R″ is methyl, n is 7, m is 17;
• and
• (f) isolating a thermoplastic vulcanizate from the 90 to 100 point of the extruder, to thereby produce a thermoplastic vulcanizate characterized by a color value L of at least 84.

A method of melt blending comprising:

• (a) providing an extruder possessing addition points from a zero point to a 100 point the length of the extruder;
• (b) adding at least one thermoplastic and ethylene-propylene-diene rubber at the zero to 10 point of the extruder;
• (c) adding at least one silicone hydride at the 5 to 30 point of the extruder, where the silicone hydride has the formula:
• wherein H is hydrogen, and each R′ is independently selected from hydrogen and C1 to C3 alkyl groups;
• R″ is selected from C1 to C3 alkyl groups;
• n is 0 or 7;
• and m is 17;
• (d) adding at least one metal catalyst at the 20 to 60 point of the extruder, with the proviso that the metal catalyst is added at least 5 points farther down the extruder than the silicone hydride;
• and
• (e) isolating a thermoplastic vulcanizate from the 90 to 100 point of the extruder.