Development of a new PVC composition with reduced flammability

Polyvinyl chloride (PVC) is one of the mostly plasticized polymers. The plasticizers used in this case are esters of aromatic or aliphatic acids with linear or branched aliphatic alcohols with a moderate chain length. Among them, phthalates (orthophthalic acid esters with fatty alcohols) have the widest range of applications among aromatic acid esters. They are characterized by excellent compatibility not only with PVC, but also with a number of other polymers, possess good physical and mechanical properties, but are toxic compounds. Therefore, their use is gradually being replaced by low-toxic and non-toxic plasticizers. Adipic acid esters which are widely used are environmentally safe. However, their use in plastic compounds for cable products requires the introduction of special additives – flame retardants. The results of the development of a low combustible PVC formulation are described herein. The dibutoxyethyl adipate developed by us was used as a plasticizer, and industrial di-(2-ethylhexyl) phenyl phosphate – as a flame retardant. First of all, we obtained an ester of adipic acid and ethoxylated butanol with a degree of ethoxylation of 5. Conditions of its production with maximum yield are selected. The physical and chemical properties of the synthesized compound were studied. Formulations of PVC compositions based on the obtained adipate with various amounts of di-(2-ethylhexyl) phenyl phosphate were compiled. Flammability tests of PVC compounds are presented. The combustible characteristics of the cable plastic samples using the developed plasticizers comply with state standard 5960-72 with changes 3-9. The best results were obtained by using phosphorus-containing additive in an amount of 3 wt%. It is shown that small amounts of di-(2-ethylhexyl) phenyl phosphate provide fire-fighting properties.