Compositions of resin-linear organosiloxane block copolymers

A process for preparing an organopolysiloxane block copolymer comprising:

• I) reacting
• a) a linear organosiloxane having the formula:
• R1q(E)(3-q)SiO(R12SiO2/2)nSi(E)(3-q)R1q,
• wherein each R1, at each occurrence, is independently a C1 to C30 hydrocarbyl or a hydrolyzable group containing at least one carbon atom,
• n is 10 to 400,
• q is 0, 1 or 2,
• E is a hydrolyzable group containing at least one carbon atom, and
• b) an organosiloxane resin comprising at least 60 mole % of [R2SiO3/2] siloxy units in its formula, wherein each R2, at each occurrence, is independently a C1 to C20 hydrocarbyl,
• in c) an organic solvent
• to form a resin-linear organosiloxane block copolymer;
• wherein the amounts of a) and b) used in step I) are selected to provide the resin-linear organosiloxane block copolymer with 5 to 65 mole % of disiloxy units [R12SiO2/2] and 35 to 95 mole % of trisiloxy units [R2SiO3/2], and
• wherein at least 95 weight percent of the linear organosiloxane used in step I) is incorporated into the resin-linear organosiloxane block copolymer;
• II) contacting said resin-linear organosiloxane block copolymer from step I) with a base bodying agent to reduce the silanol content of the resin-linear organosiloxane block copolymer to 5 mole % or less;
• III) optionally, further processing the resin-linear organosiloxane block copolymer;
• and
• IV) optionally, removing the organic solvent.