High strength silicone resin/fluid alloy compositions and method of making

Claim 2

A method in accordance with claim 1 wherein a predetermined number average of said R radicals per molecule (rRn) of said organosilicone resin (A) are reactive with said functional groups of said cross-linker (C) so as to render said organosilicone resin (A) copolymerizable with said cross-linker (C) and said predetermined number average of R groups limits the predetermined the cross-link density.

Claim 3

A method in accordance with claim 1 wherein a predetermined number average of said R' radicals per molecule (rR'n) of said predominantly linear silicone fluid (B) are reactive with said functional groups of said cross-linker (C) so as to render said fluid (B)) copolymerizable with said cross-linker (C) and said predetermined number average of R' groups limits the predetermined the cross-link density.

Claim 4

A method in accordance with claim 1 wherein said cross-linking step is carried out to said predetermined cross-link density by limiting the amount of cross-linker used.

Claim 5

A silicone resin/fluid alloy composition that exhibits high strength and toughness over a predetermined service temperature range having a lower limit of not less than -120°C. and an upper limit not greater than 250°C., said silicone resin/fluid alloy composition comprising: (A) an organosilicone resin of the empirical formula [R 3 SiO 1/2 ] a [R 2 SiO 2/2 ] b [RSiO 3/2 ] c [SiO 4/2 ] d wherein: a, b, c and d are positive numerical values with the provisos that a + b + c + d = 1 , 1/2(b + c + d) ≤ a ≤ (b + c + d) and 0 ≤ (b + c)/d ≤ 0.2; R is a monovalent radical independently selected from the group consisting of hydrogen, hydroxyl, alkyl, alkenyl, alkoxy, oximo, aryl, epoxide, carboxyl, ether, amide and alkyl amino radicals, which R groups may be the same or different, with the proviso that at least sixty mole percent of said R radicals are methyl; and the organosilicone resin (A) has a number average molecular weight (Mn) between 2,000 and 7,000; and (B) a predominantly linear silicone fluid having the empirical formula [R' 3 SiO 1/2 ] x [R' 2 SiO 2/2 ] y [R'SiO 3/2 ] z wherein: x, y and z are positive numerical values with the provisos that x + y + z = 1 and y/(x + y + z) ≥ 0:9 ; and R' is a monovalent radical independently selected from the group consisting of hydrogen, hydroxyl, alkyl, alkenyl, alkoxy, oximo, aryl, epoxide, carboxyl, ether, amide and alkyl amino radicals, which R' groups may be the same or different, with the proviso that at least ninety mole percent of said R' radicals are methyl; said organosilicon resin (A) being present in an amount of 45 to 80 parts by weight and said predominantly linear silicone fluid (B) being present in an amount of 55 to 20 parts by weight, per 100 parts, by weight of the combined total of (A) and (B); (C) a predetermined quantity of a cross-linker having at least three functional groups per molecule; a predetermined number average of said R radicals per molecule (rRn) of said organosilicone resin (A) being reactive with said functional groups of said cross-linker (C) so as to render said organosilicone resin (A) copolymerizable with said cross-linker (C); a predetermined number average of said R' radicals per molecule (rR'n) of said predominantly linear silicone fluid (B) being reactive with said functional groups of the cross-linker (C) so as to render the predominantly linear silicone fluid (B) copolymerizable with the cross-linker (C); and the respective predetermined number averages rRn and rR'n and the predetermined quantity of the cross-linker being selected such that: the silicone polymer alloy composition, when cross-linked and free of an inorganic filler, exhibits the following mechanical properties over the predetermined service temperature range: an ultimate tensile strength greater than or equal to 2.75 x 10 6 Pa; a shear loss modulus G'' greater than or equal to 10 6 Newtons per m 2 ; and a loss tangent, tan (δ) greater than or equal to 0.10.

Claim 6

A composition in accordance with claim 5 wherein rRn is between 1 and 6, inclusive.

Claim 7

A composition in accordance with claim 5 wherein rR'n is at least 2.

Claim 8

A composition in accordance with claim 7 wherein the number average of [R' 2 SiO 2/2 ] units between said at least two R' that are reactive with said functional groups of said cross-linker (C) defines a nonfunctional linear chain length and said number average nonfunctional linear chain length is between 100 and 10,000.

Claim 9

A composition in accordance with claim 8 wherein rRn is between 1 and 2.5 and said number average nonfunctional linear chain length of said predominantly linear silicone fluid (B) is between 100 and 400.

Claim 10

A composition in accordance with claim 8 wherein rRn is between 2.5 and 4 and said number average nonfunctional linear chain length of said predominantly linear silicone fluid (B) is between 400 and 2,500.

Claim 11

A composition in accordance with claim 5 further comprising a catalyst (D), said catalyst being provided in an amount sufficient to cause accelerated copolymerization between said organosilicone resin (A), said silicone fluid (B) and said cross-linker (C).

Claim 12

A composition in accordance with claim 11 further comprising: a platinum catalyst (D); said at least three functional groups of said cross-linker (C) being silicon-bonded hydrogen; said R radicals of said organosilicone resin (A) that are reactive with said at least three functional groups of said cross-linker (C) being vinyl radicals; and said R' radicals of said silicone fluid (B) that are reactive with said at least three functional groups of said cross-linker (C) being vinyl radicals.

Claim 13

A composition in accordance with claim 12 further comprising a catalyst inhibitor (E).

Claim 14

A composition in accordance with claim 5 further exhibiting optical clarity characterized by a reflectance of 2% or less.

Claim 15

A composition in accordance with claim 5 wherein said cross-linker is provided in an amount less than that required for stoichiometric reaction between the functional groups thereof and said R groups and R' groups that are reactive therewith.