Pressure-sensitive adhesives based on radiation-curable polyesters containing (meth)acrylic groups

Claim 1

A foliar material having a permanently tacky pressure-sensitive adhesive surface, said adhesive comprising (a) base polyesters which are hydroxyl polyesters liquid at room temperature having hydroxyl numbers of 10 to 100, acid numbers lower than 5, a glass transition temperature lower than 0° C., and average molecular weight of from 2,000 to 5,000, said polyesters being fluid at 20° C. and having straight-chain alkyl or branched alkyl side chains of 4 to 36 carbon atoms directly bound through ester bonds or ether bonds of at least one trifunctional of polyfunctional carboxylic acids, triols or polyfunctional polyols and hydroxydicarboxylic acids along the main chain of the polyesters, the molar ratio of ester segments of the main chain to the alkyl side chains ranging from 1:0.2 to 1:2.0, and in which 10 to 90% of the hydroxyl groups of said polyesters have been reacted with (b) acrylate compounds or methacrylate compounds having additional reactive groups capable of reacting with the hydroxyl groups of said polyesters, (c) the resultant (meth)acrylated polyester being spread as a thin coating on said foliar material and then crosslinked by means of electron beams or ultraviolet radiation.