Fast ultraviolet radiation curing silicone composition
AssigneeDow Corning Corporation
InventorsChi-long Lee, Michael A. Lutz
Life of this patent
Estimating the term…
Abstract
Compositions which cure by UV radiation in less than one second are obtained by mixing an alkenyl containing polydiorganosiloxane, a mercapto functional crosslinker of the mercapto functional polyorganosiloxane or mercapto organic compounds, a photosensitizer, a viscosity stabilizer, and optionally a reinforcing agent. These compositions can be packaged in one container and can be used as the primary coating for optical fibers.
Claims36
A composition comprising a material which is storable in one package, is viscosity stable indicated by the failure of the 25.degree. C. viscosity to double when heated at 100.degree. C. for 24 hours, cures when exposed to ultraviolet radiation of 70 millijoules or less per square cectimeter in one second or less where the ultraviolet radiation includes a wavelength of 365 nanometers, and is obtained by mixing
- (A) alkenyl functional, linear triorganosiloxy endblocked polydiorganosiloxane having a degree of polymerization of 30 to 1,000 where each silicon-bonded organic radical is selected from the group consisting of vinyl, methyl, phenyl, 3,3,3-trifluoropropyl, beta-(cyclohexenyl)ethyl, ethyl, cyclohexenyl, allyl, higher alkenyl radicals represented by the formula --R*(CH.sub.2).sub.r CH.dbd.C.H.sub.2 wherein R* is --(CH.sub.2)-- or --(CH.sub.2).sub.t Ch.dbd.CH--, r has a value of 1,2, or 3;
- s has a value of 3 or 6;
- and t has a value of 3, 4, or 5, and silacyclopentenyl, and having per molecule at least two silicon-bonded organic radicals selected from the group consisting of vinyl, beta-(cyclohexenyl)ethyl, cyclohexenyl, allyl, higher alkenyl radical, and silacyclopentenyl,
- (B) mercapto functional crosslinker which is at least one material selected from the group consisting of mercapto functional polyorganosiloxanes and mercapto organic compounds, said mercapto functional polyorganosiloxanes are represented by the general formula
- R"R'.sub.2 SiO(R'"R'SiO).sub.x (R'RSiO).sub.y SiR'.sub.2 R"
- wherein each R is selected from the group consisting of mercaptoalkyl radicals having from 2 to 6 carbon atoms per radical;
- each R' is selected from the the group consisting of methyl, phenyl, 3,3,3-trifluoropropyl, and ethyl;
- and each R" is a radical selected from the group consisting of --OH, R, and R';
- and each R'" is methyl or phenyl, on the average there being per molecule at least two mercaptoalkyl radicals, x is 0 or greater, y is 0 or greater, and the amount and kind of organic radicals represented by R, R', R", and R'" being of such a nature as to make (A) and (B) compatible, and said mercapto organic compounds have at least two mercapto groups per molecule, consisting of atoms of sulfur, carbon, and hydrogen, and optionally oxygen, having molecular weight less than 1,000, and being of such a nature as to make (A) and (B) compatible,
- (C) photosensitizer,
- (D) an amine storage stabilizer, and
- (E) reinforcing agent,
- there being in said material from 0.5 to 1.5 total alkenyl radicals per mercapto group.
A composition comprising a material which is storable in one package, is viscosity stable indicated by the failure of the 25.degree. C. viscosity to double when heated at 100.degree. C. for 24 hours, cures when exposed to ultraviolet radiation of 70 millijoules or less per square centimeter in one second or less where the ultraviolet radiation includes a wavelength of 365 nanometers, and is obtained by mixing
- (A) alkenyl functional, linear triorganosiloxy endblocked polydiorganosiloxane having a degree of polymerization of 30 to 1,000 where each silicon-bonded organic radical selected from the group consisting of vinyl, methyl, phenyl, 3,3,3 trifluoropropyl, beta-(cyclohexenyl)ethyl, ethyl, cyclohexenyl, allyl, higher alkenyl radicals represented by the formula --R*(CH.sub.2).sub.r CH.dbd.CH.sub.2 wherein R* is --(CH.sub.2).sub.s --or--(CH.sub.2).sub.t CH.dbd.CH--, r has a value of 1,2, or 3;
- s has a value of 3 or 6;
- and t has a value of 3, 4, or 5, and silacyclopentenyl, and having per molecule at least two silicon-bonded organic radicals selected from the group consisting of vinyl, beta-)cyclohexenyl)ethyl, cyclohexenyl, allyl, higher alkenyl radical and silacyclopentenyl,
- (B) mercapto functional crosslinker is mercapto organic compound having at least two mercapto groups per molecule, consisting of atoms of sulfur, carbon, and hydrogen, and optionally oxygen, having a molecular weight less than 1,000, and being of such a nature as to make (A) and (B) compatible,
- (C) photosensitizer,
- (D) storage stabilizer, and
- (E) reinforcing agent, there being in said material from 0.5 to 1.5 total alkenyl radicals per mercapto group.
A composition comprising a material which is storable in one package, is viscosity stable indicated by the failure of the 25.degree. C. viscosity to double when heated at 100.degree. C. for 24 hours, cures when exposed to ultraviolet radiation of 70 millijoules or less per square centimeter in one second or less where the ultraviolet radiation includes a wavelength of 365 nanometers, and is obtained by mixing
- (A) alkenyl functional, linear triorganosiloxy endblocked polydiogranosiloxane having a degree of polymerization of 30 to 1,000 where each silicon-bonded organic radical is selected from the group consisting of vinyl, methyl, phenyl, 3,3,3-trifluoropropyl, beta-(cyclohexenyl)ethyl, ethyl, cyclohenxenyl, allyl, silacyclopentenyl, and higher alkenyl radicals represented by the formula -R*(CH.sub.2).sub.r CH.dbd.CH.sub.2 wherein R* is --(CH.sub.2).sub.s --or --(CH.sub.2).sub.t CH.dbd.CH--, r has a value of 1, 2, or 3;
- s has a value of 3 or 6;
- to has a value of 3, 4 or 5, and having per molecule at least two silicon-bonded organic radicals selected from the group consisting of vinyl, beta-(cyclohexenyl)ethyl, cyclohexenyl, allyl, higher alkenyl radical, and silacyclopentenyl,
- (B) mercapto functional crosslinker which is at least one material selected from the group consisting of mercapto functional polyorganosiloxanes and mercapto functional organic oompounds, said mercapto functional polyorganosiloxanes are represented by the general formula
- R"R'.sub.2 SiO(R'"R'SiO).sub.x (R'RSiO).sub.y SiR'.sub.2 R"
- wherein each R is selected from mercaptoalkyl radicals having from 2 to 6 carbon atoms per radical;
- each R', is selected from the group consisting of methyl, phenyl, 3,3,3-trifluoropropyl, and ethyl;
- and each R" is a radical selected from the group consisting of--OH, R, and R';
- and each R"' is methyl or phenyl, on the average there being per molecule at least two mercaptoalkyl radicals, x is 0 or greater, y is 0 or greater, and the amount and kind of organic radicals represented by R, R', R", and R"' being of such a nature as to make (A) and (B) compatible, and said mercapto organic compounds have at least two mercapto groups per molecule, consisting of atoms of sulfur, carbon, and hydrogen, and optionally oxygen, having a molecular weight less than 1,000, and being of such a nature as to make (A) and (B) compatible,
- (C) compabible photosensitizer selected from the group consisting of benzophenone, acetophenone, benzoin methylether, benzoin isobutylether, 2,2-diethoxyacetophenone, ##STR26## (D) an amine viscosity stabilizer, and (E) reinforcing agent,
- therein being in said material from 0.5 to 1.5 total alkenyl radicals per mercapto group.
The composition according to claim in which the reinforcing agent is a siloxane resin.
Dependencies are inferred from the claim text.