Ultraviolet curable silicone adhesives
AssigneeGeneral Electric Company
InventorsSusan E. Hayes, Richard P. Eckberg
Life of this patent
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Abstract
An ultraviolet light curable silicone pressure sensitive adhesive is provided which is comprised of an epoxy functional silicone polymer and a combination of standard MQ silicone resins or epoxy functional MQ silicone resins, which can be cured to an adhesive composition in the presence of certain bis(aryl)halonium salt catalysts.
Claims14
A solventless ultraviolet radiation curable composition for forming a pressure sensitive silicone adhesive comprised of:
- (a) 100 parts by weight of an epoxy functional silicone polymer having the general formula:
- ##STR7## wherein R is a monovalent hydrocarbon radical, and R' is the same as R or a phenyl radical and R" is an epoxy-containing aliphatic or cycloaliphatic radical;
- having, approximately, 0.01 to 0.05 mole % epoxy content and a viscosity of, approximately, 100 to 5000 centipoise at 25.degree. C., .chi. is an integer representing 85 to 100 mole percent of the polymer units and y represents 0 to 15 mole percent diphenyl siloxy units;
- (b) 90 to 280 parts by weight of a silicone MQ resin or mixture of such resins selected from:
- (i) a first silicone resin comprised of mono-functional R.sub.3 SiO.sub.0.5 units and tetra-functional SiO.sub.2 units where R is as described above and the ratio of mono-functional units to tetra-functional units is, approximately, 0.5 to 2.0:1;
- or
- (ii) a second silicone resin comprised of R.sub.a R.sub.b "SiO.sub.0.5 units and SiO.sub.2 units wherein R is as described above and R" represents aliphatic or cycloaliphatic epoxide radicals;
- having, approximately, 0 to 0.005 mole % epoxy content, the sum of a band b is 3, and wherein the ratio of mono-functional to tetra-functional units is approximately 0.5 to 2.0:1, and
- (c) an amount of ultraviolet light sensitive catalyst effective for initiating the cure of said silicone adhesive composition.
A method for providing a solventless ultraviolet radiation curable composition for forming a pressure sensitive silicone adhesive comprising the steps of combining:
- (a) 100 parts by weight of an epoxy functional silicone polymer having the general average formula:
- ##STR10## wherein R is a monovalent hydrocarbon radical and R' is the same as R or a phenyl radical and R" is an epoxy-containing aliphatic or cycloaliphatic radical;
- having, approximately, 0.01 to 0.05 mole % epoxy content and a viscosity of, approximately, 100 to 5000 centipoise at 25.degree. C., .chi. is an integer representing 85 to 100 mole percent of the polymer units and y represents 0 to 15 mole percent diphenyl siloxy units;
- (b) 90 to 280 parts by weight of a silicone MQ resin or mixture of such resins selected from:
- (i) a first silicone resin comprised of mono-functional R.sub.3 SiO.sub.0.5 units and tetra-functional SiO.sub.2 units where R is as described above and the ratio of mono-functional units to tetra-functional units is, approximately, 0.5 to 2.0:1, or
- (ii) a second silicone resin comprised of R.sub.a R.sub.b "SiO.sub.0.5 units and SiO.sub.2 units wherein R is as described above and R" represents aliphatic or cycloaliphatic epoxide radicals;
- having, approximately, 0 to 0.005 mole % epoxy content, the sum of a and b is 3, and wherein the ratio of mono-functional to tetra-functional units is approximately 0.5 to 2.0:1, and
- (c) an amount of ultraviolet light sensitive catalyst effective for initiating the cure of said silicone adhesive composition.
A method as in claim 10 wherein said epoxy functional silicone polymer is dimethyl-.beta.-(3,4-epoxycyclohexyl)ethyl silyl chainstopped poly dimethyl-diphenyl siloxane copolymer.
A method of providing a solventless ultraviolet radiation curable composition for forming a silicone pressure sensitive adhesive comprising the steps of partially crosslinking a dimethylhydrogen chainstopped polydimethylsiloxane precursor fluid with up to approximately 0.005 moles of an unsaturated siloxane composition;
- reacting said partially crosslinked precursor fluid with an epoxy-containing aliphatic or cycloaliphatic species thereby providing a partially crosslinked epoxy functional silicone fluid;
- combining said epoxy functional fluid with a silicone MQ resin or mixture of such resins selected from:
- (i) a first silicone resin comprised of mono-functional R.sub.3 SiO.sub.0.5 units and tetra-functional SiO.sub.2 units where R is as described above and the ratio of mono-functional units to tetra-functional units is, approximately, 0.5 to 2.0:1, or
- (ii) a second silicone resin comprised of R.sub.a R.sub.b "SiO.sub.0.5 units and SiO.sub.2 units wherein R is as described above R" represents aliphatic or cycloaliphatic epoxide radicals;
- having, approximately, 0 to 0.005 mole % epoxy content, the sum of a and b is 3, and wherein the ratio of mono-functional to tetra-functional units is approximately 0.5 to 2.0:1;
- and adding an amount of ultraviolet light sensitive catalyst effective for initiating the cure of said curable composition.
Dependencies are inferred from the claim text.