Silicone resin coating composition

Claim 2

An aqueous coating composition comprising, in intimate admixture: (i) a dispersion of colloidal silica in a lower 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 ; and (ii) a small amount of an ultraviolet light absorbing compound, 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, and wherein said composition has a pH of from 6.8 to 7.8.

Claim 3

An aqueous coating composition as defined in claim 1 which further includes a small amount of a polysiloxane polyethr copolymer effective to control flow.

Claim 4

An aqueous coating composition as defined in claim 1 wherein said ultraviolet light absorber is a substituted hydroxybenzophenone.

Claim 5

An aqueous coating composition as defined in claim 1 wherein said ultraviolet light absorber is selected from the group consisting of 2,4-dihydroxybenzophenone, 2-hydroxy-4-methoxybenzophenone and 2,2'-dihydroxy-4-methoxybenzophenone.

Claim 6

An aqueous coating composition as defined in claim 1 wherein said ultraviolet light absorber is 2,4-dihydroxybenzophenone.

Claim 7

An aqueous coating composition as defined in claim 1 which has been aged.

Claim 8

An aqueous coating composition as defined in claim 2 which has been aged.

Claim 9

An aqueous coating composition as defined in claim 2 wherein said polysiloxane polyether copolymer has the structural formula: ##STR4## 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 10

An aqueous coating composition as defined in claim 8 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 11

An aqueous coating composition as defined in claim 1 wherein the aliphatic alcohol is a mixture of methanol and isobutanol.

Claim 12

An aqueous coating composition as defined in claim 1 wherein said partial condensate is of CH 3 Si(OH) 3 .

Claim 13

An aqueous coating composition as defined in claim 1 wherein the aliphatic alcohol is a mixture of methanol and isobutanol, the partial condensate is of CH 3 Si(OH) 3 and the composition has been aged.

Claim 14

An aqueous coating composition as defined in claim 12 which further contains a polysiloxane polyether copolymer and the ultraviolet light absorber is 2,4-dihydroxybenzophenone.

Claim 15

An aqueous coating composition as defined in claim 13 wherein the composition contains from about 18 to about 25 weight percent solids.

Claim 16

An aqueus coating composition as defined in claim 13 wherein said polysiloxane polyether copolymer is present in an amount of from about 2.5 to about 15% by weight of the total solids of the composition.

Claim 17

An aqueous coating composition as defined in claim 1 wherein the composition contains about 20% solids consisting essentially of about 32 weight percent colloidal silica, about 64 weight percent of the partial condensate and about 4 weight percent of the ultraviolet light absorbing compound.

Claim 18

An aqueous coating composition prepared by admixing an aqueous colloidal silica dispersion with a solution of an alkyltriacetoxysilane or acetic acid in an alkyltrialkoxysilane, maintaining the temperature of the admixture at from about 20° C. to about 30° C. for a sufficient time to reduce the reaction mixture to one liquid phase, maintaining the pH of the composition in the range of from about 7.1 to about 7.8, adjusting the solids content of the reaction mixture by the addition of a lower aliphatic alcohol thereto, and adding and thoroughly admixing an ultraviolet light absorbing compound to the resultant product.

Claim 19

An aqueous coating composition prepared by admixing an aqueous colloidal silica dispersion with a solution of an alkyltriacetoxysilane or acetic acid in an alkyltrialkoxysilane, maintaining the temperature of the admixture at from about 20° C. to about 30° C. for a sufficient time to reduce the reaction mixture to one liquid phase, maintaining the pH of the composition in the range of from about 7.1 to about 7.8, adjusting the solids content of the reaction mixture by the addition of a lower aliphatic alcohol thereto, and adding and thoroughly admixing an ultraviolet light absorbing compound to the resultant product.

Claim 20

An aqueous coating composition as defined in claim 17 wherein the final composition is aged.

Claim 21

An aqueous coating composition as defined in claim 18 wherein the ultraviolet light absorbing compound is a substituted hydroxybenzophenone.

Claim 22

An aqueous coating composition as defined in claim 18 wherein said alkyltrialkoxysilane is methyltrimethoxysilane, said alkyl(triacetoxy)silane is methyl(triacetoxy)silane and said aliphatic alcohol is isobutanol.

Claim 23

An aqueous coating composition as defined in claim 20 wherein said aqueous colloidal silica dispersion has a basic pH, an average particle size of about 12 millimicrons and an alkali content of about 0.10%.

Claim 24

An aqueous coating composition comprising, in intimate admixture: (i) a dispersion of colloidal silica having a particle size of from 5 to 150 millimicrons in diameter in a lower aliphatic alcohol-water solution of the partial condensation of a silanol of the formula RSi(OH) 3 , wherein R is selected from the group conssiting of alkyl having 1 to 3 carbon atoms and phenyl, wherein at least 70 weight percent of the silanol is CH 3 Si(OH) 3 ; and (ii) a small amount of an ultraviolet light absorbing compound, 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, and wherein said composition has a pH of from 6.8 to 7.8.

Claim 25

An aqueous coating composition comprising, in intimate admixture: (i) a dispersion of colloidal silica having a particle size of from 5 to 150 millimicrons in diameter in a lower aliphatic alcohol-water solution of the partial condensation of a silanol of the formula RSi(OH) 3 , wherein R is selected from the group conssiting of alkyl having 1 to 3 carbon atoms and phenyl, wherein at least 70 weight percent of the silanol is CH 3 Si(OH) 3 ; and (ii) a small amount of an ultraviolet light absorbing compound, 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, and wherein said composition has a pH of from 6.8 to 7.8.

Claim 26

An aqueous composition as defined in claim 22 which further includes from about 2.5 to about 15 weight percent of the total solids of a polysiloxane polyether copolymer having the formula: ##STR5## where R and R' are monovalent hydrocarbon radicals; R" is a lower alkyl radical; a has a value of at least 2, e.g., from about 2 to 40 or more; b has a value of from 2 to 3, n has a value of from 2 to 4 and x has a value of at least 5, e.g., from 5 to 100 or more.