Electrostatically dissipative room temperature vulcanizable silicone
A two-part RTV silicone is shown and described herein. In one aspect, provided is an electrostatically dissipative, two-part RTV silicone material. In embodiments, the silicone is white and exhibits a low thermal conductivity.
1. A two-part, room temperature vulcanizable composition comprising:
(A) a first part comprising:
(i) a silicone material containing a hydroxyl, alkoxy, or aryloxy group, and
(ii) an electrically conductive filler; and
(B) a second part comprising:
(i) a cross linker, and
(ii) a condensation curing catalyst;
wherein a material formed from a reaction of the first part (A) and the second part (B) has a volume resistivity of from 10 5 to about 10 11 ohm·cm, a thermal conductivity of about 1.0 W/m·K or less; about 0.7 W/m·K or less; or about 0.5 W/m·K, and is white in color having a L* value of about 80 or greater.
2. The composition of claim 1 , wherein the electrically conductive filler is a white electrically conductive filler having a whiteness value of at least 70.
3. The composition of claim 1 , wherein the electrically conductive filler is selected from a doped metal oxide, a non-conductive filler coated with an electrically conductive material, or a combination of two or more thereof.
4. The composition of claim 3 wherein the doped metal oxide is selected from aluminum-doped zinc oxide, antimony-doped tin oxide, tin-doped indium oxide, or a combination of two or more thereof.
5. The composition of claim 3 , wherein the non-conductive filler coated with an electrically conductive material comprises (a) a non-conductive filler material selected from titanium dioxide, zinc oxide, silica, aluminum oxide, magnesium oxide, zirconium oxide, a titanate of an alkali metal, aluminum borate, barium sulfate, or fluromica, and (b) an electrically conductive material coating selected from aluminum-doped zinc oxide, antimony-doped tin oxide, tin-doped indium oxide, or a combination of two or more thereof.
6. The composition of claim 5 , wherein the electrically conductive filler is titanium dioxide coated with antimony-doped tin oxide or aluminum-doped zinc oxide.
7. The composition of claim 1 , wherein the electrically conductive filler is present in an amount of from about 20% by weight to about 50% by weight based on the weight of the first part (A).
8. The composition of claim 1 , wherein the electrically conductive filler is present in an amount of from about 35% by weight to about 45% by weight based on the weight of the first part (A).
9. The composition of claim 1 , wherein the first part (A), the second part (B), or both the first part (A) and the second part (B) comprises a solvent.
10. The composition of claim 9 , wherein the solvent is selected from a silicone oil, a hydrocarbon based fluid, an alcohol based fluid, or a combination of two or more thereof.
11. The composition of claim 10 , wherein the solvent is a silicone oil selected from a linear or cyclic silicon oil having from 2 to 200 silicon atoms.
12. The composition of claim 11 , wherein the silicone oil is a linear silicone oil of the formula (R 26 ) 3 —Si—[O—Si(R 27 ) 2 —O] p —Si(R 28 ) 3 , where R 26 , R 27 , and R 28 are independently chosen from a C1-C20 saturated or unsaturated hydrocarbon group that is linear, branched, or cyclic, and is optionally substituted with a halo group, and p 2 to 20.
13. The composition of claim 11 , wherein the silicone oil is selected from octamethyltetrasiloxane (D4), decamethylcyclopentasiloxane (D5), dodecamethylcyclohexasiloxane (D6), heptamethyloctyltrisiloxane, hexamethyldisiloxane, decamethyltetrasiloxane, dodecamethylpentasiloxane.
14. The composition of claim 10 , wherein the solvent is an alcohol based fluid selected from a C1-C12 alcohol.
15. The composition of claim 10 , wherein the solvent is present in an amount of from about 0.5% by weight to about 75% by weight based on the weight of the composition.
16. The composition of claim 10 , wherein the solvent is present in an amount of from about 5% by weight to about 20% by weight based on the weight of the composition.
17. The composition of claim 10 , wherein the solvent is provided in the first part (A).
18. The composition of claim 1 , wherein the silicon material containing a hydroxyl, alkoxy, and/or aryloxy group is represented by 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 1 R 2 R 3 SiO 1/2
M 2 =R 4 R 5 R 6 SiO 1/2
D 1 =R 7 R 8 SiO 2/2
D 2 =R 9 R 10 SiO 2/2
T 1 =R 11 SiO 3/2
T 2 =R 12 SiO 3/2
Q=SiO 4/2
where R 1 , R 2 , R 3 , R 7 , R 8 , and R 11 are independently chosen from a hydrogen, a C 1 -C 30 aliphatic group; a C 1 -C 30 alkenyl; a C 1 -C 30 ; a C 5 -C 30 cyclic containing aliphatic group; a C 6 -C 30 aromatic containing group;
R 4 , R 5 , R 6 , R 9 , R 10 , and R 12 are independently chosen from hydrogen; a C 1 -C 30 aliphatic group; a C 1 -C 30 alkenyl; a C 1 -C 30 ; a C 5 -C 30 cyclic containing aliphatic group; a C 6 -C 30 aromatic containing group; —OH; —OR 13 where R 13 is a C 1 -C 10 alkyl or C 6 -C 30 aryl, with the proviso that at least one of R 4 , R 5 , R 6 , R 9 , R 10 , and/or R 12 is —OH or —OR 13 ;
the subscripts a, b, c, d, e, f, g, h, i, and j are zero or positive subject to the proviso that 2<a+b+c+d+e+f+g<20,000, and b+d+f>0.
19. The composition of claim 1 , wherein the crosslinker is selected from an alkoxysilane, an alkoxysiloxane, an oximosilane, an oximosiloxane, an enoxysilane, an enoxysiloxane, an aminosilane, a carboxysilane, a carboxysiloxane, an alkylamidosilane, an alkylamidosiloxane, an arylamidosilane, an arylamidosiloxane, an alkoxyaminosilane, an alkaryaminosiloxane, an alkoxycarbamatosilane, an alkoxycarbamatosiloxane, an imidatosilane, a ureidosilane, an isocyanatosilane, a thioisocyanatosilane, or combinations of two or more thereof.
20. The composition of claim 1 wherein the first part (A) comprises an additional component selected from water, a pigment, a filler, a thixotropic, or a combination of two or more thereof.
21. The composition of claim 1 , wherein the second part (B) comprises an additional component selected from a silicone material, a pigment, a filler, or a combination of two or more thereof.
22. The composition of claim 1 , wherein a mixture of part A and part B has a viscosity of from about 1,000 to about 10,000,000 cPs at 23° C. at 1 sec −1 .
23. A cured material formed from the compositions of claim 1 .
24. The cured material of claim 22 , wherein the silicone material has a volume resistivity of from 10 5 to about 10 11 ohm·cm.
25. The cured material of claim 23 , wherein the silicone material has a thermal conductivity of about 1.0 W/m·K or less; about 0.7 W/m·K or less; or about 0.5 W/m·K.
26. The cured material of claim 23 , wherein the silicone material is white in color having a L* value of about 80 or greater.
27. The cured material of claim 23 , wherein the cured material is an adhesive, sealant, or coating.
28. A method of forming a cured material comprising combining the first part (A) and the second part (B) of claim 1 and exposing the resulting mixture to moisture.