Method of providing a polycarbonate article with a uniform and durable silica filled organopolysiloxane coating

Claim 1

A method for producing a polycarbonate article having improved mar, abrasion, scratch and chemical solvent resistance and possessing enhanced ultraviolet light stability comprising: (i) applying onto a polycarbonate substrate a primer emulsion composition consisting essentially of a thermosettable acrylic polymer, (b) at least one ultraviolet light screening compound selected from the class consisting of benzylidene malonates and cyanoacrylates, (c) from about 20 to about 40 weight percent of a hydroxy ether or alkanol containing from 1 to 4 carbon atoms, and (d) water; (ii) evaporating off a substantial portion of said water and hydroxy ether or alkanol from said primer emulsion composition thereby forming a layer of comprised of said thermosettable acrylic polymer and at least one of said ultraviolet light screening compounds; (iii) applying heat to said layer at a temperature and for a period of time effective to cure said thermosettable acrylic polymer; (iv) applying onto said cured primer layer a top coat composition containing a colloidal silica filled further curable organopolysiloxane comprising a dispersion of colloidal silica in a lower aliphatic alcohol-water solution of the partial condensate of a silanol of the formula R 6 Si(OH) 3 wherein R 6 is an alkyl radical containing 1 to 3 carbon atoms, the vinyl radical, the 3,3,3-trifluoropropyl radical, the gamma-glycidoxypropyl radical and the gamma-methacryloxypropyl radical, at least 70 weight percent of said silanol being CH 3 Si(OH) 3 , said composition containing sufficient acid to provide a pH in the range of 3.0 to 6.0; (v) evaporating off a substantial portion of the volatile solvents from said top coat composition thereby forming a layer comprised of a colloidal silica filled partial condensate of said silanol; and, (vi) thermally curing said colloidal silica filled partial condensate of said silanol.

Claim 2

A method for producing a polycarbonate article having improved mar, abrasion, scratch and chemical solvent resistance and possessing enhanced ultraviolet light stability comprising: (i) applying onto a polycarbonate substrate a primer emulsion composition consisting essentially of a thermosettable acrylic polymer, (b) at least one ultraviolet light screening compound selected from the class consisting of benzylidene malonates and cyanoacrylates, (c) from about 20 to about 40 weight percent of a hydroxy ether or alkanol containing from 1 to 4 carbon atoms, and (d) water; (ii) evaporating off a substantial portion of said water and hydroxy ether or alkanol from said primer emulsion composition thereby forming a layer of comprised of said thermosettable acrylic polymer and at least one of said ultraviolet light screening compounds; (iii) applying heat to said layer at a temperature and for a period of time effective to cure said thermosettable acrylic polymer; (iv) applying onto said cured primer layer a top coat composition containing a colloidal silica filled further curable organopolysiloxane comprising a dispersion of colloidal silica in a lower aliphatic alcohol-water solution of the partial condensate of a silanol of the formula R 6 Si(OH) 3 wherein R 6 is an alkyl radical containing 1 to 3 carbon atoms, the vinyl radical, the 3,3,3-trifluoropropyl radical, the gamma-glycidoxypropyl radical and the gamma-methacryloxypropyl radical, at least 70 weight percent of said silanol being CH 3 Si(OH) 3 , said composition containing sufficient acid to provide a pH in the range of 3.0 to 6.0; (v) evaporating off a substantial portion of the volatile solvents from said top coat composition thereby forming a layer comprised of a colloidal silica filled partial condensate of said silanol; and, (vi) thermally curing said colloidal silica filled partial condensate of said silanol.

Claim 16

A method for providing a uniform and durably adhered mar, scratch, abrasion and chemical solvent resistant colloidal silica filled organopolysiloxane coating on a polycarbonate article which comprises: (i) applying onto the surface of a polycarbonate substrate a primer emulsion composition consisting essentially of, in percent by weight, (a) from about 1 to about 10 percent of a thermosettable acrylic polymer, (b) from about 1 to about 10 percent of at least one ultraviolet light screening compound selected from the class consisting of benzylidene malonates and cyanoacrylates, (c) from 20 to about 40 percent of a hydroxy ether or an alkanol containing from 1 to 4 carbon atoms, and (d) from about 40 to about 78 percent water; (ii) evaporating off a substantial portion of said water and hydroxy ether or alkanol from said primer emulsion composition thereby forming a layer comprised of said thermosettable acrylic polymer and at least one of said ultraviolet light screening compounds; (iii) applying heat to said layer at a temperature and for a period of time effective to cure said thermosettable acrylic polymer; (iv) applying onto said cured primer layer a colloidal silica filled further curable organopolysiloxane top coat composition comprising 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 an alkyl radical containing 1 to 3 carbon atoms, the vinyl radical, the 3,3,3-trifluoropropyl radical, the gamma-glycidoxypropyl radical and the gamma-methacryloxypropyl radical, at least 70 weight percent of said silanol being CH 3 Si(OH) 3 , said composition containing sufficient acid to provide a pH in the range of 3.0 to 6.0; (v) evaporating off a substantial portion of the volatile solvents from said top coat composition thereby forming a layer comprised of a colloidal silica filled partial condensate of said silanol; and, (vi) thermally curing said colloidal silica filled partial condensate of said silanol.

Claim 17

A method for providing a uniform and durably adhered mar, scratch, abrasion and chemical solvent resistant colloidal silica filled organopolysiloxane coating on a polycarbonate article which comprises: (i) applying onto the surface of a polycarbonate substrate a primer emulsion composition consisting essentially of, in percent by weight, (a) from about 1 to about 10 percent of a thermosettable acrylic polymer, (b) from about 1 to about 10 percent of at least one ultraviolet light screening compound selected from the class consisting of benzylidene malonates and cyanoacrylates, (c) from 20 to about 40 percent of a hydroxy ether or an alkanol containing from 1 to 4 carbon atoms, and (d) from about 40 to about 78 percent water; (ii) evaporating off a substantial portion of said water and hydroxy ether or alkanol from said primer emulsion composition thereby forming a layer comprised of said thermosettable acrylic polymer and at least one of said ultraviolet light screening compounds; (iii) applying heat to said layer at a temperature and for a period of time effective to cure said thermosettable acrylic polymer; (iv) applying onto said cured primer layer a colloidal silica filled further curable organopolysiloxane top coat composition comprising 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 an alkyl radical containing 1 to 3 carbon atoms, the vinyl radical, the 3,3,3-trifluoropropyl radical, the gamma-glycidoxypropyl radical and the gamma-methacryloxypropyl radical, at least 70 weight percent of said silanol being CH 3 Si(OH) 3 , said composition containing sufficient acid to provide a pH in the range of 3.0 to 6.0; (v) evaporating off a substantial portion of the volatile solvents from said top coat composition thereby forming a layer comprised of a colloidal silica filled partial condensate of said silanol; and, (vi) thermally curing said colloidal silica filled partial condensate of said silanol.