Compositions of resin-linear organosiloxane block copolymers
View Patent ↗Curable compositions of “resin-linear” organosiloxane block copolymers comprising a metal ligand complex are disclosed. The addition of a metal ligand complex to compositions of certain resin-linear organosiloxane block copolymers results in curable compositions having faster cure rates, and improved mechanical strength and/or thermal stability over similar compositions without the metal ligand complex.
1. A curable composition comprising:
i) an organosiloxane block copolymer comprising:
40 to 90 mole percent disiloxy units of the formula [R 1 2 SiO 2/2 ],
10 to 60 mole percent trisiloxy units of the formula [R 2 SiO 3/2 ],
0.5 to 35 mole percent silanol groups [≡SiOH];
wherein:
each R 1 , at each occurrence, is independently a C 1 to C 30 hydrocarbyl,
each R 2 , at each occurrence, is independently a C 1 to C 20 hydrocarbyl;
wherein:
the disiloxy units [R 1 2 SiO 2/2 ] are arranged in linear blocks having an average of from 10 to 400 disiloxy units [R 1 2 SiO 2/2 ] per linear block,
the trisiloxy units [R 2 SiO 3/2 ] 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 (M w ) of at least 20,000 g/mole; and
ii) a metal ligand complex.
2. The curable composition of claim 1 , further comprising a solvent, a filler or a phosphor.
3. The curable composition of claim 1 , wherein the metal ligand complex comprises a metal acetylacetonate complex.
4. The curable composition of claim 1 , wherein the metal is Al, Bi, Sn, Ti or Zr.
5. The curable composition of claim 1 , wherein the metal ligand complex comprises a tetravalent tin-containing metal ligand complex.
6. The curable composition of claim 1 , wherein the metal ligand complex comprises a dialkyltin dicarboxylate.
7. The curable composition of claim 1 , wherein the metal ligand complex comprises dimethyltin dineodecanoate.
8. The curable composition of claim 1 , wherein R 2 is phenyl.
9. The curable composition of claim 1 , wherein R 1 is methyl or phenyl.
10. The curable composition of claim 1 , wherein the disiloxy units have the formula [(CH 3 )(C 6 H 5 )SiO 2/2 ].
11. The curable composition of claim 1 , wherein the disiloxy units have the formula [(CH 3 ) 2 SiO 2/2 ].
12. The curable composition of claim 1 , further comprising a stabilizer.
13. A solid film composition comprising the curable composition of claim 1 .
14. The solid film composition of claim 13 , wherein the solid composition has an optical transmittance of at least 95%.
15. The cured product of the composition of claim 1 .
16. An LED encapsulant comprising the compositions of claim 1 .
17. 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 [R 1 2 SiO 2/2 ],
10 to 60 mole percent trisiloxy units of the formula [R 2 SiO 3/2 ],
0.5 to 35 mole percent silanol groups [≡SiOH];
wherein:
each R 1 , at each occurrence, is independently a C 1 to C 30 hydrocarbyl,
each R 2 , at each occurrence, is independently a C 1 to C 20 hydrocarbyl;
wherein:
the disiloxy units [R 1 2 SiO 2/2 ] are arranged in linear blocks having an average of from 10 to 400 disiloxy units [R 1 2 SiO 2/2 ] per linear block,
the trisiloxy units [R 2 SiO 3/2 ] 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 (M w ) of at least 20,000 g/mole.
18. The method of claim 17 , wherein the cure onset temperature is maintained within about 20% of the cure onset temperature of the composition lacking the filler and/or phosphor.
19. The method of claim 17 , wherein the cure onset temperature of the composition lacking the filler is less than 220° C.
20. The method of claim 17 , wherein the cure onset temperature of the composition lacking the filler is from about 120° C. to about 220° C.
21. The method of claim 17 , wherein the composition comprising the filler comprises from about 2% to about 90% filler based on the total weight of the composition.
22. The method of claim 17 , wherein the composition comprising the phosphor comprises from about 5% to about 80% phosphor based on the total weight of the composition.
23. 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 [R 1 2 SiO 2/2 ],
10 to 60 mole percent trisiloxy units of the formula [R 2 SiO 3/2 ],
0.5 to 35 mole percent silanol groups [≡SiOH];
wherein:
each R 1 , at each occurrence, is independently a C 1 to C 30 hydrocarbyl,
each R 2 , at each occurrence, is independently a C 1 to C 20 hydrocarbyl;
wherein:
the disiloxy units [R 1 2 SiO 2/2 ] are arranged in linear blocks having an average of from 10 to 400 disiloxy units [R 1 2 SiO 2/2 ] per linear block,
the trisiloxy units [R 2 SiO 3/2 ] 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 (M w ) of at least 20,000 g/mole.