Addition curable silicone adhesive compositions

1. A curable silicone composition comprising:

(a) an alkenyl functional silicone; (b) a silicone hydride cross linker; (c) a filler; (d) a first adhesion promoter; (e) a second adhesion promoter; (f) optionally, a silane; (g) optionally an inhibitor; and (h) optionally a catalyst;

wherein the first adhesion promoter is chosen from a compound of the formula Z 1 —R 1 —O—Ar—O—R 2 —Z 2 where R 1 and R 2 are a C1-C30 divalent hydrocarbon; a C2-C20 divalent hydrocarbon; a C4-C10 divalent hydrocarbon; or a C1-C4 divalent hydrocarbon;

Z 1 and Z 2 are independently:

provided that at least one of Z 1 and Z 2 is

where R 3 , R 4 , R 5 , R 6 , R 7 , R 8 , R 9 , and R 10 are independently chosen from H, a C1-C10 alkyl, or —OR 11 , where R 11 is a C1-C10 alkyl, and at least one of R 3 , R 4 , R 5 , R 6 , R 7 , R 8 , R 9 , and/or R 10 are H;

x is 1 to 10;

y is 2 to 10; and

Ar is an aromatic group;

wherein the second adhesion promoter is chosen from one or more compounds of the formula R 47 —SiR 48 r (OR 49 ) 3-r where R 47 is a cyclic hydrido siloxane containing group of the formula:

R 48 is independently selected from a C1-C10 hydrocarbon group; each R 49 is independently selected from a C1-C10 hydrocarbon; r is 0, 1, or 2:

R 51 , R 52 , and R 53 are independently chosen from H, a C1-C10 alkyl, or —OR 54 , where R 54 is a C1-C10 alkyl, and at least one of R 51 , R 52 , and R 53 are H; and R 50 is an organosilicon group having a side chain bonded to a silicon atom and represented by the following formula

Q 1 -C(O)—O-Q 2

wherein Q 1 represents a linear or branched alkylene group that forms a carbon chain having two or more carbon atoms between a silicon atom in R 47 and an ester bond, and Q 2 represents a linear or branched alkylene group that forms a carbon chain having three or more carbon atoms between an oxygen atom and a silicon atom in SiR 48 r (OR 49 ) 3-r ; and

wherein the first adhesion promoter and the second adhesion promoter are included in the curable silicone composition in different amounts by weight.

2. The curable silicone composition of claim 1 , wherein the aromatic group Ar is chosen from a C6-C30 arylene group, or a group of the formula —Ar 1 —X—Ar 2 —, where Ar 1 and Ar 2 are independently chosen from a monocyclic divalent aryl group and X is a bridging group.

3. The curable silicone composition of claim 2 , wherein Ar 1 and Ar 2 are independently chosen from a C6-C30 arylene group, X is chosen from a bond connecting Ar 1 and Ar 2 , a C1-C30 divalent hydrocarbon group, a C5-C30 divalent cyclic hydrocarbon group, —O—, —S—, —S(O)—, —S(O) 2 —, or —C(O)—.

4. The curable silicone composition of claim 2 , wherein Ar 1 —X—Ar 2 is a group of the formula:

where X is chosen from a bond connecting Ar 1 and Ar 2 , a C1-C30 divalent hydrocarbon group, a C5-C30 divalent cyclic hydrocarbon group, —O—, —S—, —S(O)—, —S(O) 2 —, or —C(O)—; R 12 and R 13 are the same or different from each other and are chosen from hydrogen, a C1-C10 alkyl, C1-C10 alkoxy, a C2-C8 alkenyl, a C2-C8 alkenyloxy, a C3-C8 cycloalkyl, a C3-C8 cycloalkoxy, a C6-C10 aryl, a C6-C10 aryloxy, a C7-C10 aralkoxy, a C7-C12 alkylaryl, or a C7-C12 alkylaryloxy, and t and w are 0-4.

5. The curable silicone composition of claim 2 , wherein Ar 1 —X—Ar 2 is of the formula:

where X is as described above, and R 14 , R 15 , R 16 , R 17 , R 18 , R 19 , R 20 , and R 21 are independently selected from hydrogen, a C1-C10 alkyl, a C3-C8 cycloalkyl, or a C6-C10 aryl.

6. The curable silicone composition of claim 5 , wherein X is —C(R 22 ) 2 — where R 22 is independently selected from hydrogen, a C1-C10 alkyl, a C3-C8 cycloalkyl, or a C6-C10 aryl.

7. The silicone compound of claim 6 , wherein Z 1 and Z 2 are:

8. The curable silicone composition of claim 1 , wherein the O—Ar—O of the first adhesion promoter is of the formula:

9. The curable silicone composition of claim 1 , wherein the first adhesion promoter is present in an amount of from about 0.1 wt. % to about 5 wt. % based on the total weight of the composition.

10. The curable composition of claim 1 , further comprising a third adhesion promoter chosen from one or more compounds of the formula —R 57 —SiR 58 z (OR 59 ) 3-z where R 57 is a hydrogen or hydride functional group other than R 47 ; R 58 is independently selected from a C1-C10 hydrocarbon group; each R 59 is independently selected from a C1-C10 hydrocarbon; and z is 0, 1, or 2.

11. The curable composition of claim 1 , wherein r is 0, and R 49 is a C1-C10 alkyl group.

12. The curable composition of claim 1 , wherein the second adhesion promoter is present in an amount of from about 0.1 wt. % to about 10 wt. % based on the total weight of the composition.

13. The curable silicone composition of claim 10 , wherein second adhesion promoter is present in an amount of about 0.1 wt. % to about 8 wt. %, and the third adhesion promoter is present in an amount of about 0.5 wt. % to about 3 wt. %.

14. The curable silicone composition of claim 1 , wherein the alkenyl functional silicone is chosen from a compound of the formula M 1 a M 2 b D 1 c D 2 d T 1 e T 2 f Q g

wherein:

M=R 23 R 24 R 25 SiO 1/2

M 2 =R 26 R 27 R 28 SiO 1/2

D 1 =R 29 R 30 SiO 2/2

D 2 =R 31 R 32 SiO 2/2

T 1 =R 33 SiO 3/2

T 2 =R 34 SiO 3/2

Q=SiO 4/2

where R 23 ,R 24 , R 25 , R 27 , R 28 , R 29 , R 30 , R 32 , and R 33 are independently chosen from a C1-C30 hydrocarbon, a C6-C30 aromatic group, or C1-C30 alkoxy group;

R 26 , R 31 , and R 34 are independently chosen from a C1-C30 hydrocarbon, a C6-C30 aromatic group, C1-C30 alkoxy group, or a C2-C30 alkenyl group, with the proviso that one or more of R 26 , R 31 , and/or R 34 are selected from a C2-C30 alkenyl group; and

subscripts a, b, c, d, e, f, g, are zero or a positive number, 2<a+b+c+d+e+f+g<2000, and b+d+f>0.

15. The curable silicone composition of claim 14 , wherein the alkenyl functional silicone comprises: a first alkenyl function silicone having the formula M 2 D 1 c M 2 where c is from about 5 to about 1000; and a (ii) second alkenyl functional silicone having the formula M 2 D 1 c′ M 2 where c′ is from about 1000 to about 1500.

16. The curable composition of claim 14 , wherein the alkenyl functional silicone is a branched polyorganosiloxane comprising a plurality of Q g units and one or more M 2 units.

17. The curable silicone composition of claim 1 , wherein the silicone hydride crosslinker is chosen from a compound of the formula:

M 3 h M 4 i D 3 j D 4 k T 3 m T 4 n Q o

wherein:

M 3 =R 35 R 36 R 37 SiO 1/2

M 4 =R 38 R 39 R 40 SiO 1/2

D 3 =R 41 R 42 SiO 2/2

D 4 =R 43 R 44 SiO 2/2

T 3 =R 45 SiO 3/2

T 4 =R 46 SiO 3/2

Q=SiO 4/2

where R 35 , R 36 , R 37 , R 41 , R 42 , R 45 , and are independently chosen from a C1-C30 hydrocarbon, a C6-C30 aromatic group, or C1-C30 alkoxy group;

R 38 , R 39 , R 40 , R 43 , R 44 , and R 46 are independently chosen from hydrogen, a C1-C30 hydrocarbon, a C6-C30 aromatic group, C1-C30 alkoxy group, or a C2-C30 alkenyl group, with the proviso that one or more of R 38 , R 39 , R 40 , R 43 , R 44 , and/or R 46 are hydrogen;

subscripts a, b, c, d, e, f, g, are zero or a positive number, 1<h+i+j+k+m+n+o<100, and i+k+n>0.

18. A cured silicone material formed from the curable silicone composition of claim 1 .

19. A method of forming an adhesive coating on a substrate comprising:

applying the curable silicone composition of claim 1 to a surface of a substrate, and heating the curable silicone composition at a temperature of about 50° C. to about 110° C.

20. The method of claim 19 comprising heating the curable silicone composition at a temperature of about 60° C. to about 100° C.

21. The method of claim 19 , wherein the curable silicone composition is cured over a period of 10 minutes to about 3 hours.

22. The method of claim 19 , wherein the substrate is chosen from a plastic material, a metal, a metal alloy, a metallized plastic, and/or a coated or painted metal.