Polymer compositions for UV curable primer formulations, as described herein. The primer formulations contain a modifier selected from the following: at least one modifier selected from a) through d) below: a) R1R2C═CR3-(CO)—Z (Formula A), as described herein, b) an acrylate-containing oligomer that has a Mn≤1500 g/mol, and an acid value from 50 to 500 mg KOH/g; c) a random terpolymer comprising, in polymerized form, vinyl chloride, vinyl acetate, and at least one of the following: a hydroxyl-containing alkyl acrylate, a hydroxyl-containing alkyl meth-acrylate, or a combination thereof or d) any combination of a) through c). Such primer formulations are useful for the binding of olefin-based polymer foams.