Vinyl chloride resins plasticized with copolymers of an acrylate and either ethylene or propylene

The invention comprises a liquid copolymer of propylene, or a mixture of propylene and ethylene, and ethyl acrylate, methyl acrylate, or methyl methacrylate said copolymer having a viscosity in the range of from H to Z10 on the Gardner-Holdt scale (equivalent to 2 to 1066 poises), an acid number which does not exceed 3, a molecular weight (ebulliometric) between 500 and 1500, and a molar ratio of olefinic monomer to acrylic monomer ranging from 1 to 3, in which ratio the upper limit is a fuction of molecular weight as expressed by the equation: Moles of olefin/mole of acrylic monomer= where X = 1 + 0.75 x/100 for ethyl acrylate and methyl methacrylate and X = 1.25 + x/100 for methyl acrylate, x being the percentage by weight of ethylene in the olefinic monomer. The products are used as plasticizers for vinyl chloride resins.