The alkyl epoxyhexahydrophthalates represent a new class of improved epoxy plasticizers with built-in stabilizing properties, protecting poly(viny1 chloride) resins against degradation caused by heat and light. They are primary plasticizers and show excellent compatibility at high concentration use levels with no evidence of bleed after prolonged exposure to light.As combination stabilizer-plasticizers they are applicable to a wide range of vinyl resin formulations and products-e. g., hose, toys, flooring, packaging, film, and foam THE epoxy plasticizers, widely used in vinyl resin processing, are epoxy fatty acid esters (5, 6, 72, 13)) prepared by epoxidation of unsaturated fatty acid esters of mono-and polyhydric alcohols. A new series, alkyl epoxyhexahydrophthalates, has been developed in these laboratories in a broad program of research on epoxy plasticizers. The epoxyhexahydrophthalates combine the excellent stabilizing properties of the epoxy fatty acid esters with the good over-all plasticizing properties of the phthalates. They are compatible with poly(viny1 chloride) at primary use levels and show no evidence of bleed, sometimes observed with specific epoxy fatty acid ester plasticizers at high use levels, after prolonged exposure to ultraviolet or diffused light.
ExperimentalThe epoxyhexahydrophthalate esters (4, 70) can be prepared by epoxidation of the corresponding unsaturated tetrahydrophthalic acid esters with preformed peracetic acid or by in situ techniques (2,3, 7,9) employing hydrogen peroxide.The reaction can be represented schematically as:The tetrahydrophthalate esters were made by esterifying n-butyl, n-hexyl, isooctyl, and n-decyl alcohols (Enjay Co., Inc.) with tetrahydrophthalic anhydride (National Aniline Division) in the presence of an acid catalyst, water-washed, and vacuum-distilled.The in situ epoxidation process (8) is illustrated below for the preparation of di-2-ethylhexylepoxyhexahydrophthalate.One hundred grams of di-2-ethylhexyltetrahydrophthalate (Union Carbide Chemicals) and 20 grams of benzene were weighed into a three-necked flask equipped with a reflux condenser, thermometer, and a mechanical stirrer; 7.7 grams of glacial acetic acid and 1.