Patent GB-890642-A (GB)
Title: Improvements in or relating to aryl phosphates
IPC: C08K5/523
Filed: 1957-03-14
Abstract: The invention comprises a synthetic resin, e.g. polyvinyl chloride, containing as a plasticizer therefore a mixture of trialkaryl phosphates free from phosphates containing one or more orthomonoalkylphenyl radicals (see Group IV(b) ).  The phosphate mixture is non-toxic and is preferably a mixture of tritolyl phosphates free from phosphates containing one or more o-cresyl and o-ethylphenyl radicals or a mixture of trixylenyl phosphates free from phosphates containing one or more o-cresyl, o-ethylphenyl and o-propylphenyl radicals.  The plasticized synthetic resin may be used in the manufacture of food wrappings and articles which come in contact with the human body, e.g. pants for babies.  Specification 890,643 is referred to.ALSO:The invention comprises a mixture of trialkaryl phosphates suitable for use as a nontoxic plasticiser which mixture is free from phosphates containing one or more ortho-monoalkylphenyl radicals, and particularly a mixture of tritolyl phosphates free from phosphates containing one or more ortho-cresyl and orthoethylphenyl radicals and a mixture of trixylenyl phosphates free from phosphates containing one or more ortho-cresyl, ortho-ethylphenyl and ortho-propylphenyl radicals.  The content of tri-2 : 4/2 : 5-dimethylphenyl phosphates and of phosphates containing one or two 2 : 4/2 : 5-dimethylphenyl radicals in the mixture of trixylenyl phosphates should preferably be below 10% by weight but the mixture may contain phosphates of meta- and para-ethylphenol and of 2-methyl-4-ethyl-phenol.  The phosphate mixture may be obtained by reacting a phenolic fraction free from o-monoalkyl phenols, e.g. a cresol fraction free from o-cresol and o-ethyl-phenol and/or a xylenol free from ortho-cresol, ortho-ethyl phenol and ortho-propyl phenol, with a phosphating agent, preferably phosphorus oxychloride.  Examples are given for the production of (1) a non-toxic tritolyl phosphate mixture from a tar acid cresol fraction comprising meta-cresol (48%), para-cresol (35%) and 2 : 4/2 : 5-dimethylphenol (17%), and (2) a trixylenyl phosphate mixture from a tar acid fraction having a boiling range of 220 DEG C.-232.5 DEG C. and comprising 3 : 5-xylenyl (31%), meta/para-ethylphenol (16%), 3,4-xylenol (18%), 2-methyl-4-ethylphenol and 2-methyl-5-ethylphenol (30%) and 5% of other phenols, the fraction being free from o-cresol, o-ethylphenol and o-n-propylphenol.  The phenolic fractions are obtained by careful fractionation of a coal tar fraction by the procedure described in Specification 890,643.  Toxicity tests of the phosphate products on chickens aged between 3 and 12 months show the products to be completely non-toxic.  The products are useful as plasticisers for synthetic resins, e.g. polyvinyl chloride (see Group IV (a)).  The first Provisional Specification also discloses the production of a trixylenyl phosphate from a xylenol fraction having an Engler boiling range of 217 DEG C.-225 DEG C. and having the following composition by volume: 2,4/2,5 -dimethyl-phenol (5%) meta- and para-ethylphenol (40%), 2,3-dimethylphenol (10%) mesitol (5%), 3,5-dimethylphenol (20%), 2-methyl-4-ethylphenol (10%) and 3,4-dimethylphenol (10%).