Compositions of resin-linear organosiloxane block copolymers

1. 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 or a C 1 to C 30 hydrocarbyl group comprising at least one aliphatic unsaturated bond,

each R 2 , at each occurrence, is independently a C 1 to C 30 hydrocarbyl or a C 1 to C 30 hydrocarbyl group comprising at least one aliphatic unsaturated bond;

wherein:

the disiloxy units [R 1 2 SiO 2/2 ] are arranged in linear blocks having an average of from 100 to 300 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;

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 via —Si—O—Si— linkages;

the organosiloxane block copolymer has a weight average molecular weight of at least 20,000 g/mole; and

the organosiloxane block copolymer comprises from about 0.5 to about 4.5 mole % C 1 to C 30 hydrocarbyl group comprising at least one aliphatic unsaturated bond.

2. The organosiloxane block copolymer of claim 1 , wherein the organosiloxane block copolymer comprises 12 to 22 mole percent silanol groups [≡SiOH].

3. The organosiloxane block copolymer of claim 1 , wherein the organosiloxane block copolymer has a weight average molecular weight of about 40,000 g/mole to about 250,000 g/mole.

4. The organosiloxane block copolymer of claim 1 , wherein the organosiloxane block copolymer comprises 1 to 35 mole percent silanol groups [≡SiOH].

5. The organosiloxane block copolymer of claim 1 , wherein the organosiloxane block copolymer comprises 30 to 60 mole percent trisiloxy units of the formula [R 2 SiO 3/2 ].

6. A composition comprising the reaction product of:

A) a resin linear 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 free of aliphatic unsaturation,

each R 2 , at each occurrence, is independently a C 1 to C 30 hydrocarbyl free of aliphatic unsaturation;

wherein:

the disiloxy units [R 1 2 SiO 2/2 ] are arranged in linear blocks having an average of from 50 to 300 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, 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 of at least 20,000 g/mole; and

B) a compound of the formula R 1 R 2 2 SiX

wherein each R 1 , at each occurrence, is independently a C 1 to C 30 hydrocarbyl free of aliphatic unsaturation or a C 1 to C 30 hydrocarbyl group comprising at least one aliphatic unsaturated bond,

each R 2 , at each occurrence, is independently a C 1 to C 30 hydrocarbyl free of aliphatic unsaturation or a C 1 to C 30 hydrocarbyl group comprising at least one aliphatic unsaturated bond, and

X is a hydrolyzable group chosen from —OR 4 , F, Cl, Br, I, —OC(O)R 4 , —N(R 4 ) 2 , or —ON═CR 4 2 , wherein R 4 is hydrogen or a C 1 to C 6 alkyl group that may be optionally substituted;

wherein the reaction product is an organosiloxane block copolymer and the organosiloxane block copolymer comprises from about 0.5 to about 5 mole % C 1 to C 30 hydrocarbyl group comprising at least one aliphatic unsaturated bond.

7. The composition of claim 6 , wherein the resin linear organosiloxane block copolymer has a weight average molecular weight of about 40,000 g/mole to about 250,000 g/mole.

8. The composition claim 6 , wherein the organosiloxane block copolymer comprises 1 to 35 mole percent silanol groups [≡SiOH].

9. The composition of claim 6 , wherein the organosiloxane block copolymer comprises 30 to 60 mole percent trisiloxy units of the formula [R 2 SiO 3/2 ].

10. A composition comprising the reaction product of:

A) a linear organosiloxane having the formula:

R 1 3-p (E) p SiO(R 1 2 SiO 2/2 ) n Si(E) p R 1 3-p ,

wherein each R 1 , at each occurrence, is independently a C 1 to C 30 hydrocarbyl free of aliphatic unsaturation,

n is 50 to 300,

E is a hydrolyzable group chosen from —OR 4 , F, Cl, Br, I, —OC(O)R 4 , —N(R 4 ) 2 , or —ON═CR 4 2 , wherein R 4 is hydrogen or a C 1 to C 6 alkyl group, and

each p is, independently, 1; 2 or 3; and

B) an organosiloxane resin comprising unit formula:

[R 1 2 R 2 SiO 1/2 ] a [R 1 R 2 SiO 2/2 ] b [R 1 SiO 3/2 ] c [R 2 SiO 3/2 ] d [SiO 4/2 ] e ,

wherein:

each R 1 , at each occurrence, is independently a C 1 to C 30 hydrocarbyl free of aliphatic unsaturation or a C 1 to C 30 hydrocarbyl group comprising at least one aliphatic unsaturated bond,

each R 2 , at each occurrence, is independently a C 1 to C 30 hydrocarbyl free of aliphatic unsaturation or a C 1 to C 30 hydrocarbyl group comprising at least one aliphatic unsaturated bond,

wherein the organosiloxane resin comprises 0.5 to 35 mole % silanol groups [≡SiOH], and

the subscripts a, b, c, d, and e represent the mole fraction of each siloxy unit present in the organosiloxane resin and range as follows:

a is about 0 to about 0.6,

b is about 0 to about 0.6,

c is about 0 to about 1,

d is about 0 to about 1,

e is about 0 to about 0.6,

with the provisos that b+c+d+e>0 and a+b+c+d+e≦1;

wherein the reaction product is an organosiloxane block copolymer and the organosiloxane block copolymer comprises from about 0.5 to about 5 mole C 1 to C 30 hydrocarbyl group comprising at least one aliphatic unsaturated bond.

11. A composition comprising the reaction product of:

A) a linear organosiloxane having the formula:

R 1 3-p (E) p SiO(R 1 2 SiO 2/2 ) n Si(E) p R 1 3-p ,

wherein each R 1 , at each occurrence, is independently a C 1 to C 30 hydrocarbyl free of aliphatic unsaturation,

n is 50 to 300,

E is a hydrolyzable group chosen from —OR 4 , F, Cl, Br, I, —OC(O)R 4 , —N(R 4 ) 2 , or —ON═CR 4 2 , wherein R 4 is hydrogen or a C 1 to C 6 alkyl group, and

each p is, independently, 1, 2 or 3, and

B) an organosiloxane resin comprising unit formula:

[R 1 2 R 2 SiO 1/2 ] a [R 1 R 2 SiO 2/2 ] b [R 1 SiO 3/2 ] c [R 2 SiO 3/2 ] d [SiO 4/2 ] e ,

wherein:

each R 1 , at each occurrence, is independently a C 1 to C 30 hydrocarbyl free of aliphatic unsaturation,

each R 2 , at each occurrence, is independently a C 1 to C 30 hydrocarbyl free of aliphatic unsaturation,

wherein the organosiloxane resin comprises 0.5 to 35 mole % silanol groups [≡SiOH], and

the subscripts a, b, c, d, and e represent the mole fraction of each siloxy unit present in the organosiloxane resin and range as follows:

a is about 0 to about 0.6,

b is about 0 to about 0.6,

c is about 0 to about 1,

d is about 0 to about 1,

e is about 0 to about 0.6,

with the provisos that b+c+d+e>0 and a+b+c+d+e≦1; and

C) a compound of the formula R 1 q SiX 4-q

wherein each R 1 , at each occurrence, is independently a C 1 to C 30 hydrocarbyl free of aliphatic unsaturation or a C 1 to C 30 hydrocarbyl group comprising at least one aliphatic unsaturated bond,

q is 0, 1 or 2, and,

each X is independently a hydrolyzable group chosen from —OR 4 , F, Cl, Br, I, —OC(O)R 4 , —N(R 4 ) 2 , or —ON═CR 4 2 , wherein R 4 is hydrogen or a C 1 to C 6 alkyl group that may be optionally substituted;

wherein the reaction product is an organosiloxane block copolymer and the organosiloxane block copolymer comprises from about 0.5 to about 5 mole % C 1 to C 30 hydrocarbyl group comprising at least one aliphatic unsaturated bond.

12. The composition of claim 11 , wherein the product of the contacting between A) and B) is contacted with C).

13. The composition of claim 6 , wherein the reaction product is contacted with a compound of the formula R 5 q SiX 4-q , wherein each R 5 is independently a C 1 to C 8 hydrocarbyl or a C 1 to C 8 halogen-substituted hydrocarbyl; and each X is independently a hydrolyzable group chosen from —OR 4 , F, Cl, Br, I, —OC(O)R 4 , —N(R 4 ) 2 , or —ON═CR 4 2 , wherein R 4 is hydrogen or a C 1 to C 6 alkyl group that may be optionally substituted.

14. The composition of claim 10 , wherein E is acetoxy and p is 1.

15. The composition of claim 6 further comprising a compound having unit formula:

[R 1 2 SiO 1/2 ] a [R 1 R 2 SiO 2/2 ] b [R 1 SiO 3/2 ] c [R 2 SiO 3/2 ] d [SiO 4/2 ] e

comprising 0 to 35 mole % silanol groups [≡SiOH],

wherein:

each R 1 , at each occurrence, is independently H, a silane radical of the formula —[R 5 R 6 Si] k [R 5 R 6 SiH] (wherein R 5 , R 6 are independently a H or a C 1 to C 30 hydrocarbyl free of aliphatic unsaturation, k is an integer from 0 to 10) or a C 1 to C 30 hydrocarbyl free of aliphatic unsaturation,

each R 2 , at each occurrence, is independently H or, a silane radical of the formula —[R 5 R 6 Si] k [R 5 R 6 SiH] (wherein R 5 , R 6 are independently a H or a C 1 to C 30 hydrocarbyl free of aliphatic unsaturation, k is an integer from 0 to 10) a C 1 to C 30 hydrocarbyl free of aliphatic unsaturation,

wherein the subscripts a, b, c, d, and e represent the mole fraction of each siloxy unit present and range as follows:

a is about 0 to about 0.6,

b is about 0 to about 0.6,

c is about 0 to about 1,

d is about 0 to about 1,

e is about 0 to about 0.6,

with the provisos that:

b+c+d+e>0 and a+b+c+d+e≦1, and

at least 1 mole % of R 1 and/or R 2 are H or SiH containing silane radical.

16. The composition of claim 6 further comprising a hydrosilylation catalyst.

17. The composition of claim 6 , further comprising free resin that is not part of the block copolymer.

18. The composition of claim 6 , wherein the composition is curable.

19. The curable composition of claim 18 , wherein the curable composition has a cure speed in Pa/min of from about 1 to about 20 Pa/min at a heating rate of 5° C./min.

20. The curable composition of claim 18 , wherein the curable composition is curable via at least two curing mechanisms.

21. The curable composition of claim 20 , wherein said at least two curing mechanisms comprise hydrosylilation cure and condensation cure.

22. The composition of claim 6 , wherein the composition is solid.

23. The composition of claim 22 , further comprising free resin that is not part of the block copolymer.

24. The composition of claim 22 , wherein the solid composition is a solid film composition.

25. The composition of claim 22 , wherein the solid film composition has an optical transmittance of at least 95% at a film thickness of 0.5 mm or greater.

26. The cured product of the compositions of claim 6 .

27. The cured product of claim 26 , wherein the product is cured in the absence of a condensation catalyst.

28. The cured product of claim 26 , wherein the product is cured in the presence of a phosphor or a filler.

29. The cured product of claim 26 , wherein the ratio of the Young's modulus of the cured product after aging for 50 hours at 225° C. and the Young's modulus before aging is less than 3.

30. The cured product of claim 26 , wherein the cured product generates less than 200 ppm benzene after 30 minutes at 180° C.

31. The cured product of claim 26 , wherein the CIE b* value after aging for 72 h at 235° C. is no more than about 6.