Dual component coating system

Claim 2

An article comprising a solid substrate, at least one surface of which is coated with (a) an inner layer consisting of a primer coat comprising from 2% to 6% polymethylmethacrylate dissolved in a mixture of an ether solvent and ketone solvent containing an ultraviolet light absorbing compound, or a combination of an ultraviolet light absorbing compound and an ultraviolet radiation stabilizing agent, effective to increase the resistance of the coating to ultraviolet radiation; and (b) an outer layer consisting of a silicone resin coating composition comprising a dispersion of colloidal silica in an aliphatic alcohol-water solution of the partial condensate of a silanol of the formula RSi(OH) 3 , wherein R is selected from the group consisting of alkyl having from 1 to 3 carbon atoms and aryl, wherein at least 70 weight percent of the silanol is CH 3 Si(OH) 3 , said composition containing 10 to 50 weight percent solids, said solids consisting essentially of 10 to 70 weight percent colloidal silica and 30 to 90 weight percent of the partial condensate, said composition further containing an effective amount of an ultraviolet light absorbing compound which is not the same as that employed in component (a) and which is matched with said ultraviolet light absorbing compound of component (a) so as to effectively extend the service life of the coated substrate.

Claim 3

An article as defined by claim 1, wherein component (b) also includes a small amount of a polysiloxane polyether copolymer.

Claim 4

An article as defined in claim 1 wherein said combination in component (a) comprises a substituted cyanoacrylate and a hindered amine.

Claim 5

An article as defined by claim 1, wherein the ratio of ether solvent to ketone solvent in component (a) is about 4:1.

Claim 6

An article as defined by claim 4, wherein the ether solvent is ethylene glycol monoethyl ether and the ketone solvent is diacetone alcohol.

Claim 7

An article as defined by claim 1, wherein the solid substrate is a synthetic organic polymer.

Claim 8

An article as defined by claim 6, wherein the synthetic organic polymer is transparent.

Claim 9

An article as defined by claim 6, wherein the synthetic organic polymer is a polycarbonate.

Claim 10

An article as defined in claim 1, wherein said UV light absorber in component (a) is a substituted benzotriazole.

Claim 11

An article as defined in claim 9 wherein said ultraviolet light absorber in component (a) is 2-hydroxy-5-octylphenyl benzotriazole.

Claim 12

A process for protecting and extending the service life of a solid substrate comprising applying and curing on at least one surface of said solid substrate (1) a primer coat comprising from 2% to 6% polymethylmethacrylate dissolved in a mixture of an ether solvent and ketone solvent containing an ultraviolet light absorbing compound, or a combination of an ultraviolet light absorbing compound and an ultraviolet radiation stabilizing agent, effective to increase the resistance of the coat to ultraviolet radiation; and (2) a silicone resin coating composition comprising a dispersion of colloidal silica in an aliphatic alcohol-water solution of the partial condensate of a silanol of the formula RSi(OH) 3 , wherein R is selected from the group consisting of alkyl having from 1 to 3 carbon atoms and aryl, wherein at least 70 weight percent of the silanol is CH 3 Si(OH) 3 , said composition containing 10 to 50 weight percent solids, said solids consisting essentially of 10 to 70 weight percent colloidal silica and 30 to 90 weight percent of the partial condensate, said composition further containing an effective amount of an ultraviolet light absorbing compound which is not the same as that employed in component (a) and which is matched with said ultraviolet light absorbing compound of component (a) so as to effectively extend the service life of the solid substrate.

Claim 13

A process for protecting and extending the service life of a solid substrate comprising applying and curing on at least one surface of said solid substrate (1) a primer coat comprising from 2% to 6% polymethylmethacrylate dissolved in a mixture of an ether solvent and ketone solvent containing an ultraviolet light absorbing compound, or a combination of an ultraviolet light absorbing compound and an ultraviolet radiation stabilizing agent, effective to increase the resistance of the coat to ultraviolet radiation; and (2) a silicone resin coating composition comprising a dispersion of colloidal silica in an aliphatic alcohol-water solution of the partial condensate of a silanol of the formula RSi(OH) 3 , wherein R is selected from the group consisting of alkyl having from 1 to 3 carbon atoms and aryl, wherein at least 70 weight percent of the silanol is CH 3 Si(OH) 3 , said composition containing 10 to 50 weight percent solids, said solids consisting essentially of 10 to 70 weight percent colloidal silica and 30 to 90 weight percent of the partial condensate, said composition further containing an effective amount of an ultraviolet light absorbing compound which is not the same as that employed in component (a) and which is matched with said ultraviolet light absorbing compound of component (a) so as to effectively extend the service life of the solid substrate.

Claim 14

A process as defined in claim 11 wherein said combination in said primer coat comprises a substituted cyanoacrylate and a hindered amine.

Claim 15

A process as defined in claim 11 wherein the aliphatic alcohol in said silicone resin coating composition is a mixture of methanol and isobutanol.

Claim 16

A process as defined in claim 11 wherein the silicone resin coating composition further includes a small amount of a polysiloxane polyether copolymer.

Claim 17

A process as defined in claim 14 wherein said polysiloxane polyether compolymer has the structural formula: ##STR1## wherein R and R' are monovalent hydrocarbon radicals; R" is a lower alkyl radical, a has a value of at least 2; b has a value of from 2 to 3, inclusive, n has a value of from 2 to 4, inclusive, and x has a value of at least 5.

Claim 18

A process as defined in claim 15 wherein R is methyl, R' is methyl, R" is butyl, a is 4, b is 3, n is 2.4 and x is 28.5.

Claim 19

A process as defined in claim 11 wherein said ultraviolet light absorber in said primer coat is a substituted benzotriazole.

Claim 20

A process as defined in claim 17 wherein said ultraviolet light absorber in said primer coat is 2-hydroxy-5-octylphenyl benzotriazole.

Claim 21

A process as defined in claim 11 wherein the ratio of ether solvent to ketone solvent in said primer coat is 4:1.

Claim 22

A process as defined in claim 19 wherein the ether solvent is ethylene glycol monoethyl ether and the ketone solvent is diacetone alcohol.