The widespread use of synthetic polymers has led to the accumulation of their wastes, of which only about 10% is processed, the rest is accumulated in nature, and decomposition in natural conditions occurs for a long time. Therefore, the development of biodegradable plasticates is important. Today, plastics based on plant raw materials do not compete with traditional plastics, since they have unsatisfactory operational properties, and their production technologies consume a significant amount of energy and water and are characterized by emissions of pollutants. The development of composites from traditional plastics with biodegradable additives, which are completely compostable in nature, is relevant. Plasticizers, as the main part of plasticate, are the most convenient way to model the biodegradability of the composite. When developing biodegradable plasticate, it is important to ensure a certain service life. For this purpose, fungicides with a limited duration are used. Zinc compounds are known among them. Therefore, in the presence of catalyst ZnO, a new non-toxic plasticizer, decyl phenoxyethyl adipate, was obtained in 89% yield. Method of its co-production with zinc compound has been developed. For the use of decyl phenoxyethyl adipate in PVC composites by TGA and DSC (Mettler Toledo), thermal stability, crystallization and melting temperatures of the plasticizer, enthalpy values ​ ​ of these processes were studied; PVC compatibility is estimated by the critical dissolution temperature of the polymer in the plasticizer. Effect of zinc compound formed in situ as fungicide on biodegradation of PVC film samples with developed plasticizer is investigated. As a result of the tests, the obtained zinc compound in an amount of 5% in the formulation of the PVC composition provides a fungicidal effect for a certain period of operation of the obtained plasticate, after which the biodegradation process begins.