Silane primer for improving the adhesion of adhesive tapes on hydrophilic surfaces, especially glass surfaces

Abstract

The invention relates to a primer, comprising a mixture dissolved or dispersed in one or more solvents, the mixture composed of a copolymer obtained through copolymerization, preferably free-radical copolymerization, of vinylcaprolactam and/or vinylpyrrolidone, and one or more of the following monomers: a) an acrylic acid ester of a linear primary alcohol containing 2 to 10 carbon atoms in the alkyl group of the alcohol, b) an acrylic acid ester of a branched, non-cyclic alcohol having 4 to 12 carbon atoms in the alkyl group of the alcohol, c) acrylic acid, one or more organofunctional silanes. Such primer provides reliable and excellent adhesion between pressure-sensitive adhesive tapes and hydrophilic surfaces, in particular glass. The adhesion-promoting effect is retained even when the primer additionally contains functional fillers.

1 . A primer, comprising a mixture dissolved or dispersed in one or more solvents, the mixture comprising:
 one or more organofunctional silanes; and,   a copolymer obtained through copolymerization, preferably free-radical copolymerization, of vinylcaprolactam and/or vinylpyrrolidone, and one or more of the following monomers:   a) an acrylic acid ester of a linear primary alcohol containing 2 to 10 carbon atoms in the alkyl group of the alcohol,   b) an acrylic acid ester of a branched, non-cyclic alcohol having 4 to 12 carbon atoms in the alkyl group of the alcohol,   c) acrylic acid.   
     
     
         2 . A primer according to  claim 1  wherein the copolymer is a pressure-sensitive adhesive. 
     
     
         3 . A primer according to  claim 1 , wherein the copolymer contains additionally up to 10 percent by weight of additional copolymerizable monomers, based on the sum of the monomers. 
     
     
         4 . A primer according to  claim 1  wherein in that the copolymer contains a maximum of 50 weight-percent, preferably a maximum of 40 weight-percent, of vinylcaprolactam and/or vinylpyrrolidone, based on the sum of all monomers of the copolymer contains. 
     
     
         5 . A primer according to  claim 1  wherein in that the copolymer contains at least 10 weight-percent, preferably at least 20 weight-percent, of vinylcaprolactam and/or vinylpyrrolidone, based on the sum of all monomers of the copolymer. 
     
     
         6 . A primer according to  claim 1  wherein the copolymer contains a maximum of 20 weight-percent, preferably a maximum of 10 weight-percent, particularly preferred 0 weight-percent, of acrylic acid, based on the sum of all monomers of the copolymer. 
     
     
         7 . A primer according to  claim 1  wherein one of the monomers from which the copolymer is constructed is butyl acrylate. 
     
     
         8 . A primer according to  claim 1  wherein the organofunctional silane is glycidoxy-functional. 
     
     
         9 . A primer according to  claim 1  wherein the organofunctional silane is amino-functional or vinyl-functional. 
     
     
         10 . A primer according to  claim 1  wherein the solvent is isopropanol or another alcohol or contains isopropanol or another alcohol. 
     
     
         11 . A primer according to  claim 1  wherein the concentration of the copolymer of the mixture dissolved or dispersed in the one or more solvents is higher than the concentration of the one or more organo functional silanes. 
     
     
         12 . A primer according to  claim 1  wherein the concentration of the copolymer of the mixture dissolved or dispersed in the one or more solvents is between and including 1.0 weight-percent and including 30.0 weight-percent. 
     
     
         13 . A primer according to  claim 1  wherein the mixture additionally contains one or more fluorescent brighteners. 
     
     
         14 . A method of preparing an adhesion-promoting layer, preferably for the preparation of an adhesion-promoting layer containing functional fillers, which method comprises the step of:
 providing a primer according to  claim 1 .   
     
     
         15 . A method for producing an adhesion-promoting layer on a substrate, comprising applying a primer according to  claim 1  on a substrate and letting the one or more solvents evaporate. 
     
     
         16 . A primer according to  claim 12 , wherein the concentration of the copolymer of the mixture dissolved or dispersed in the one or more solvents is between and including 2.0 weight-percent and including 20.0 weight-percent. 
     
     
         17 . A primer according to  claim 16 , wherein the concentration of the copolymer of the mixture dissolved or dispersed in the one or more solvents is between and including 3.0 weight-percent and including 10.0 weight-percent.