Compositions of resin-linear organosiloxane block copolymers

A method of maintaining the cure onset temperature of a composition comprising a resin linear organosiloxane block copolymer and a filler and/or a phosphor, within about 40% of the cure onset temperature of a composition comprising the resin linear organosiloxane block copolymer, but lacking the filler and/or phosphor, the method comprising contacting the composition comprising a resin linear organosiloxane block copolymer and a filler and/or a phosphor with a metal ligand complex;

• wherein:
• wherein the composition comprising a resin linear organosiloxane block copolymer is a curable composition comprising:
• an organosiloxane block copolymer comprising;
• 40 to 90 mole percent disiloxy units of the formula [R12SiO2/2],
• 10 to 60 mole percent trisiloxy units of the formula [R2SiO3/2],
• 0.5 to 35 mole percent silanol groups [≡SiOH];
• wherein:
• each R1, at each occurrence, is independently a C1 to C30 hydrocarbyl,
• each R2, at each occurrence, is independently a C1 to C20 hydrocarbyl;
• wherein:
• the disiloxy units [R12SiO2/2] are arranged in linear blocks having an average of from 10 to 400 disiloxy units [R12SiO2/2] per linear block,
• the trisiloxy units [R2SiO3/2] are arranged in non-linear blocks having a molecular weight of at least 500 g/mole, and at least 30% of the non-linear blocks are crosslinked with each other, each linear block is linked to at least one non-linear block;
• and
• the organosiloxane block copolymer has a weight average molecular weight (Mw) of at least 20,000 g/mole.

A method of maintaining the time necessary to reach a tan delta value equal to 1 of a composition comprising a resin linear organosiloxane block copolymer and up to a total of 80 wt. % of a filler and/or a phosphor, within about 40% of the time necessary to reach a tan delta value equal to 1 of a composition comprising the resin linear organosiloxane block copolymer, but lacking the filler and/or phosphor, the method comprising contacting the composition comprising a resin linear organosiloxane block copolymer and a filler and/or a phosphor with a metal ligand complex;

• wherein:
• wherein the composition comprising a resin linear organosiloxane block copolymer is a curable composition comprising:
• an organosiloxane block copolymer comprising:
• 40 to 90 mole percent disiloxy units of the formula [R12SiO2/2],
• 10 to 60 mole percent trisiloxy units of the formula [R2SiO3/2],
• 0.5 to 35 mole percent silanol groups [≡SiOH];
• wherein:
• each R1, at each occurrence, is independently a C1 to C30 hydrocarbyl,
• each R2, at each occurrence, is independently a C1 to C20 hydrocarbyl;
• wherein:
• the disiloxy units [R12SiO2/2] are arranged in linear blocks having an average of from 10 to 400 disiloxy units [R12SiO2/2] per linear block,
• the trisiloxy units [R2SiO3/2] are arranged in non-linear blocks having a molecular weight of at least 500 g/mole and at least 30% of the non-linear blocks are crosslinked with each other, each linear block is linked to at least one non-linear block;
• and
• the organosiloxane block copolymer has a weight average molecular weight (Mw) of at least 20,000 g/mole.