Addition curable silicone adhesive compositions
A curable silicone adhesive composition comprising a combination of adhesion promoters is shown and described herein. The composition includes a first adhesion promoter selected from a silicon hydride adhesion promoter and a second adhesion promoter selected from an acrylate functional adhesion promoter to provide a silicone material that is curable at relatively low temperatures and shorter time and provides good adhesion to plastics and metal.
1 . A curable silicone composition comprising: (a) an alkenyl functional silicone; (b) a silicone based cross linker; (c) a first adhesion promoter selected from a silicon hydride containing adhesion promoter having at least one Si—H group; (d) a second adhesion promoter selected from an acrylate functional adhesion promoter; (e) optionally, a silane; (f) optionally, a filler; (g) an inhibitor; and (h) a catalyst, wherein the first adhesion promoter and the second adhesion promoter are present in an amount such that there is a molar ratio of Si—H to ethylenically-unsaturated groups from the first and second adhesion promoters of from 1.5:1 to 2.5:1.
2 . The curable silicone composition of claim 1 , wherein the first adhesion promoter is selected from a compound of the formula (I):
Z 1 —R 1 —O—Ar—O—R 2 —Z 2 (I)
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:
where R 3 , R 4 , R 5 , R 6 , R 7 , R 8 , R9, and R 10 are independently chosen from H, a C1-C10 alkyl, or —OR11, 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.
3 . The curable silicone composition of claim 2 , wherein the aromatic group Ar may be 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.
4 . The curable silicone composition of claim 3 , 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)—.
5 . The curable silicone composition of claim 3 , 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 or within the ring to which they are attached 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, wherein when t or w are less than 4, the unspecified valence or valencies is occupied by hydrogen.
6 . The curable silicone composition of claim 3 , 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.
7 . The curable silicone composition of claim 6 , 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.
8 . The curable silicone composition of claim 7 , wherein Z 1 and Z 2 in Formula (I) are:
9 . The curable silicone composition of claim 2 , wherein the O—Ar—O in Formula (I) is:
10 . The curable silicone composition of claim 1 , wherein the first adhesion promoter is selected from a compound of the formula (VI):
R 23 —SiR 24 r (OR 25 ) 3-r (VI)
where R 23 is a hydrogen or hydride functional group; R 24 is independently selected from a C1-C10 hydrocarbon group; each R 25 is independently selected from a C1-C10 hydrocarbon; and r=0, 1, or 2.
11 . The curable composition of claim 10 , wherein R 23 is a cyclic hydrido siloxane containing group of the formula (VII):
where R 27 , R 28 , and R 29 are independently chosen from H, a C1-C10 alkyl, or —OR 30 , where R 54 is a C1-C10 alkyl, and at least one of R 27 , R 28 , and R 29 are H; and R 26 is a divalent C1-C30 hydrocarbon; a divalent C6-C30 aryl group; or a divalent ester group.
12 . The curable composition of claim 11 , wherein R 23 is a cyclic hydrido siloxane of formula (VII), and R 26 is 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 the silicon atom and an ester bond, in embodiments 2-20 carbon atoms, 4-15 carbon atoms, or 6-10 carbon atoms, 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.
13 . The curable composition of claim 2 wherein the first adhesion promoter (c) comprises (i) an adhesion promoter of formula (I), and (ii) an adhesion promoter of formula (VI):
R 23 —SiR 24 r (OR 25 ) 3-r (VI)
where R 23 is a hydrogen or hydride functional group; R 24 is independently selected from a C1-C10 hydrocarbon group; each R 25 is independently selected from a C1-C10 hydrocarbon; and r=0, 1, or 2.
14 . The curable composition of claim 1 , wherein the second adhesion promoter is selected from:
(i) a compound of the formula CH2=CR 30 C(O)O—R 31 where R 30 is selected from H or a C1-C10 alkyl; and R 31 is selected from a C1-C20 alkyl, a C3-C20 cycloalkyl, a C6-C30 aryl, a fused C6-C30 cycloalkyl, a C7-C30 arylalkyl, a bridged C7-C30 cycloalkyl, a C1-C20 heteroalkyl, or a cyclic C3-C20 heteroalkyl, where the R 31 groups may optionally contain a heteroatom or a heteroatom-containing functional group; and/or
(ii) a compound of the formula CH2=CR 32 C(O)O—R 34 —O(O)CR 33 C=CH2 where R 32 and R 33 are independently selected from H or a C1-C10 alkyl; and
R 34 is selected from a C1-18 alkylene group, a C3-18 cycloalkylene group, a fused C6-18 cycloalkylene group, or a group of the formula —B 1 —W—B 2 — wherein B 1 and B 2 are the same or different C1-6 alkylene group and W is a C3-12 cycloalkylene group, a C6-16 arylene group, a C6-C30 bridged cycloalkylene group, or a C12-C36 fused aromatic group.
15 . The curable composition of claim 1 , wherein the first 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; and 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.
16 . The curable composition of claim 1 , wherein the first adhesion promoter and the second adhesion promoter are present in an amount such that there is a molar ratio of Si—H to vinyl groups from the first and second adhesion promoters of 2:1.
17 . The curable silicone composition of claim 1 , wherein the alkenyl 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 1 =R 35 R 36 R 37 SiO 1/2
M 2 =R 38 R 39 R 40 SiO 1/2
D 1 =R 41 R 42 SiO 2/2
D 2 =R 43 R 44 SiO 2/2
T 1 =R 45 SiO 3/2
T 2 =R 46 SiO 3/2
Q =SiO 4/2
where R 35 , R 36 , R 37 , R 39 , R 40 , R 41 , R 42 , R 44 , and R 45 are independently chosen from a C1-C30 hydrocarbon, a C6-C30 aromatic group, or C1-C30 alkoxy group;
R 38 , R 43 , and R 46 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 38 , R 43 , and/or R 46 are selected from a C2-C30 alkenyl group;
the subscripts a, b, c, d, e, f, g, are zero or positive subject to the following limitations: 2<a+b+c+d+e+f+g<2000, b+d+f>0.
18 . The curable silicone composition of claim 17 , wherein the alkenyl silicone comprises a mixture of alkenyl silicones chosen from (i) 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 500 to about 1500.
19 . The curable composition of claim 17 , wherein the alkenyl silicone is a branched polyorganosiloxane comprising a plurality of Q g units and one or more M 2 units.
20 . 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 47 R 48 R 49 SiO 1/2
M 4 =R 50 R 51 R 52 SiO 1/2
D 3 =R 53 R 54 SiO 2/2
D 4 =R 55 R 56 SiO 2/2
T 3 =R 57 SiO 3/2
T 4 =R 58 SiO 3/2
Q=SiO 4/2
where R 47 , R 48 , R 49 , R 53 , R 54 , R 57 , and are independently chosen from a C1-C30 hydrocarbon, a C6-C30 aromatic group, or C1-C30 alkoxy group;
R 50 , R 51 , R 52 , R 55 , R 56 , and R 58 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 50 , R 51 , R 52 , R 55 , R 56 , and/or R 58 are hydrogen;
the subscripts a, b, c, d, e, f, g, are zero or positive subject to the following limitations: 1<h+i+j+k+m+n+o<100, i+k+n>0.
21 . The curable silicone composition of claim 1 comprising the filler (f) in an amount of from about 1 weight % to about 50 weight % based on the total weight of the curable silicone composition.
22 . The curable composition of claim 21 , wherein the filler is selected from precipitated calcium carbonate, colloidal calcium carbonate, fumed silica, precipitated silica, silica gel, hydrophobized silica, a hydrophobized silica gelm crushed quartz, ground quartz, alumina, aluminum hydroxide, titanium hydroxide, diatomaceous earth, iron oxide, carbon black, graphite, a clay.
23 . A cured silicone material formed from the composition of claim 1 .
24 . A method of forming an adhesive coating on a substrate comprising:
applying a curable composition of claim 1 to a surface of a substrate, and heating the composition at a temperature of about 80° C. to about 100° C.
25 . The method of claim 24 , wherein the composition is cured over a period of 5 minutes to about 15 minutes.
26 . The method of claim 24 comprising heating the composition at a temperature of about 100° C. for 5 minutes.
27 . The method of claim 24 , wherein the substrate is chosen from a plastic material, metal, metal alloys, metallized plastic, and/or coated or painted metal.
28 . A curable silicone composition comprising: (a) an alkenyl functional silicone; (b) a silicone based cross linker; (c) a first adhesion promoter selected from a silicon hydride containing adhesion promoter having at least one Si—H group; (d) a second adhesion promoter selected from an acrylate functional adhesion promoter; (e) optionally, a silane; (f) optionally, a filler; (g) an inhibitor; and (h) a catalyst;
wherein the first adhesion promoter (c) comprises (i) an adhesion promoter of formula (I), and (ii) an adhesion promoter of formula (VI):
Z 1 —R 1 —O—Ar—O—R 2 —Z 2 (I)
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:
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 —OR11, 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;
R 23 —SiR 24 r (OR 25 ) 3-r (VI)
where R 23 is a hydrogen or hydride functional group; R 24 is independently selected from a C1-C10 hydrocarbon group; each R 25 is independently selected from a C1-C10 hydrocarbon; and r=0, 1, or 2.