Patent GB-815301-A (GB)
Title: Process of improving the plasticizing properties of epoxidized esters and new epoxidized ester products
Filed: 1955-08-26
Abstract: Synthetic resins such as polyvinyl chloride, polyvinyl butyral, polyvinylidene chloride, and copolymers of vinyl chloride with vinylidene chloride or vinyl esters such as vinyl acetate, and also nitrocellulose and chlorinated rubbers, are plasticized, according to one embodiment of the invention, by means of acylated and epoxidized ester products prepared by acylating an epoxidized ester product obtained by epoxidation of a water-insoluble olefinically unsaturated ester, which product contains ester molecules having, as a result of the epoxidation reaction, one or more hydroxy groups in vicinal relationship with a formoxy group, an acyloxy group or another hydroxy group, and contains also more than 15 per cent of the theoretical maximum amount of oxirane oxygen, the acylation being conducted by reacting the epoxidized ester product with an acylating agent comprising acetic, propionic or butyric anhydride, ketene, methyl ketene or ethyl ketene and, if desired, an acid corresponding to one of the anhydrides, so as to convert the hydroxy groups and formoxy groups, if present, to acetoxy, propionoxy or butyroxy groups, and controlling the degree of acylation so that there is retained in the acylated product at least 15 per cent of the theoretical maximum oxirane oxygen content (see Group IV (b)).  In another embodiment the plasticizer is a mixture of substantially completely saturated water-in-soluble esters obtainable, as above described, by acylation of at least one epoxidized water-insoluble olefinically unsaturated ester product, wherein the ester molecules of the mixture collectively contain epoxy and vicinal acyloxy groups in the ratio of at least 4 epoxy groups for each pair of vicinal acyloxy groups, the acyloxy groups being acetoxy, propionoxy or butyroxy groups and these and the epoxy groups constituting the sole substituents of the ester molecules.  Numerous examples of unsaturated esters from which the plasticizers may be derived are listed and include esters wherein the unsaturation occurs in the acid or alcohol residue or in both.  Examples describe the plasticizing of polyvinyl chloride, containing minor amounts of basic lead sulphate and stearic acid, by means of epoxidized esters acetylated as above described and prepared from epoxidized 2-ethyl hexyl oleate, epoxystearyl 2-ethyl hexanoate and epoxidized soybean oil.  Their plasticizing properties are compared with those of the corresponding epoxidized esters not subjected to the acylation treatment and the treated esters are shown to be more resistant to leaching by washing waters. Specification 741,492 is referred to.ALSO:Modified acylated and epoxidized ester products are prepared by a process comprising acylating an epoxidized ester product obtained by epoxidation of a water-insoluble olefinically unsaturated ester, and which contains ester molecules having, as a result of the epoxidation reaction, one or more hydroxy groups in vicinal relationship with a formoxy group, an acyloxy group or another hydroxy group, and which contains more than 15 per cent of the theoretical maximum amount of oxirane oxygen, the acylation being conducted by reacting the epoxidized ester product with an acylating agent comprising acetic anhydride, propionic anhydride, butyric anhydride, ketene, methyl ketene or ethyl ketene so as to convert the hydroxy groups, and formoxy groups if present, to acetoxy, propionoxy or butyroxy groups as the case may be and controlling the degree of acylation so that there is retained in the acylated product at least 15 per cent of the theoretical maximum amount of oxirane oxygen.  The invention also comprises a mixture of substantially completely saturated water-insoluble esters obtainable by the above specified acylation of at least one epoxidized water-insoluble olefinically unsaturated ester product, wherein the ester molecules of the mixture collectively contain epoxy and vicinal acyloxy groups in the ratio of at east 4 epoxy groups for each pair of vicinal acyloxy groups, the acyloxy groups being acetoxy, propionoxy or butyroxy groups and these acyloxy and epoxy groups constituting the sole substituents of the ester molecules. The acylation process may be carried out, according to one method, by using the acid anhydrides or ketenes alone and preferably in excess. This method results in substantially no opening of the oxirane rings especially if the acid formed as by product when using the acid anhydride is continuously removed by distillation.  Temperatures from 0-200 DEG  C., preferably about 100-150 DEG  C., may be used.  This method is employed to obtain the mixtures of modified epoxy esters described above.  The acylation may also be effected using one of the above-mentioned acylating agents in conjunction with acetic, propionic or butyric acid and this results in a limited number of the epoxy groups in the ester molecules being opened and converted into vicinal acyloxy groups. The acid may be added to the acid anhydride or ketene or may be that resulting from reaction of the acid anhydride with the hydroxyl groups in the ester.  A temperature of about 100-200 DEG  C. is used and a neutral or slightly basic salt such as sodium acetate may be present.  The products of this degradative acylation preferably contain 2 to about 20 pairs of vicinal acyloxy groups for every 4 epoxy groups.  The process may be applied to the products obtained by the epoxidation of esters of saturated mono- and polyhydric alcohols including, for example, ethyl, tert.-butyl, octadecyl and benzyl alcohols and ethylene glycol, diethylene glycol, butanediols, glycerol and pentaerythritol, with mono- and poly-olefinically unsaturated acids including, for example, undecylenic, oleic, linolenic and erucic acid for example, hexyl and octyl oleates and vegetable oils; esters of mono- and poly-olefinically unsaturated alcohols, such as oleyl, linoleyl and linolenyl alcohols, with saturated acids such as acetic, butyric and hexoic acids; and esters of unsaturated alcohols with unsaturated acids such as oleyl undecylenate and linoleyl oleate.  The acylated epoxy ester products are improved plasticisers for such plastics as vinyl resins, nitrocellulose and chlorinated rubber (see Group IV (a)). In examples: (1) 2-ethylhexyl epoxy stearate, obtained by epoxidizing 2-ethyl hexyl oleate by means of H2O2, formic acid and a little phosphoric acid, is boiled with acetic anhydride with continuous removal of acetic acid by distillation and is then stripped of acetic anhydride; (2) epoxy stearyl-2-ethyl hexanoate is similarly post-acylated; (3) soya-bean oil is epoxidized by means of H2O2 and formic acid and the product is washed neutral, dried and filtered and is then post-acylated as in (1), the oxirane oygen content being thereby reduced from 6.03 per cent to 5.54; (4) an epoxidized soya bean oil prepared substantially as in (3) is refluxed with acetic anhydride and a little sodium acetate (without removal of the acetic acid formed) yielding an acetylated epoxy ester product in which the oxirane oxygen content has been reduced from 5.97 to 3.0 per cent; (5) epoxidized linseed oil is similarly acetylated yielding a product in which the oxirane oxygen content has been reduced from 7.86 to 3.3 per cent. Specification 741,492 is referred to.