Glyceryl-Tri-3,5,5-Trimethylhexanoate Protecting the Skin Therewith and Cosmetic Compositions Therefore

The present invention relates to a new compound and to new compositions of matter for cosmetic use, and more particularly to oils, creams, emulsions and ointments used as skin-protecting agents.

Skin creams used for cosmetic purposes, which provide protection against harmful outside agents when applied to the surface of the skin, generally contain water-repellant hydrocarbons, natural or synthetic waxes, and/or natural fats.

Natural fats usually represent mixtures of the various triglycerides whose fatty acid components contain 14, 16 or 18 carbon atoms in a straight chain.

If the fatty acids are saturated, the fats usually have a firm consistency, are not stretchable, and have only slight spreadability. If the triglycerides contain unsaturated fatty acids, the solidification point drops and the fats become more stretchable or liquid, but have the disadvantage of readily turning rancid by oxidation when exposed to the air and are therefore unsuitable for cosmetic purposes. In all cases, special preservatives must be added to preparations containing natural fats.

It has now been found that glyceryl-tri-3,5,5-trimethylhexanoate, which is a new compound, is particularly suitable for use in cosmetic preparations, since the consistency and the spreadability of this branch-chained triglyceride permits it to spread well on the skin and coat it in an extremely protective manner.

The multiple branching of the carbon chain of the acid components of this triglyceride is the reason why this compound is an oily liquid at room temperature and possesses unusually great spreadability. One advantage of this compound is also that it cannot be decomposed by the bacterial flora of the skin nor changed into substances harmful to the skin because of the branching of the carbon chain which does not occur in this form in nature. Moreover, oxidation by atmospheric oxygen is impossible because of the lack of unsaturated centers and because of steric prevention of oxygen attack by the branching. This has an advantageous effect on the stability and shelf life of cosmetic products containing glyceryl-tri-3,5,5-trimethylhexanoate.

When the new glycerol ester in accordance with the present invention is used in skin-protecting agents, it is usually applied in quantities of 2% to 15% according to the type of preparation.

All percent figures are in weight percent and all parts are parts by weight.

In oils, the new glycerol ester is preferably used in quantities of 5% to 15%,

in creams, in quantities of 2% to 5%,

in emulsions, in quantities of 2% to 5%, and

in ointments, in quantities of 2% to 5%.

Glyceryl-tri-3,5,5-trimethylhexanoate can be produced analogously to known process by converting glycerol with 3,5,5-trimethyl hexanoic acid chloride in the presence of a basic catalyst (B. F. Daubert and A. R. Baldwin, J. Amer. Chem. Soc., Vol. 66, 1944, p. 997).

The following examples will illustrate the invention. They show the manufacture and application of the new glycerol ester.

Glycerol (25 g) is dissolved with pyridine (70 g) in chloroform (750 ml). 150 g 3,5,5-trimethyl hexanoic acid chloride are added slowly to this solution under agitation and this mixture is heated for two hours at 100.degree. C. After cooling, the reaction mixture is dissolved in 3.5 liters of petroleum ether and this solution is washed first with 5% cold sulfuric acid, then with 5% sodium carbonate solution, and finally with water. The remaining organic phase is dried with sodium sulfate and the solvent is distilled off.

The glyceryl-tri-3,5,5-trimethylhexanoate yield is: 108 g (79% of theoretical); D.sub.4.sup.20 =0.9452 n.sub.D.sup.20 =1.4482.

This example shows a number of recipes for skin-protecting agents containing the new glycerol ester.

The novel glyceryl-tri-3,5,5-trimethylhexanoate may also be added to base compositions for any preparations which are to be applied to the skin, to which base compositions in a further step of manufacture are then added further compounds as for instance perfume oils and/or pharmaceutically active agents and other usual components to make the final product.

Such base compositions are for instance:

Such base compositions are often supplied to manufacturers of medical or cosmetic creams or other preparations for use on the skin by other manufacturers who are specialized in such base compositions but do not produce the final preparation. The novel spreading agent glyceryl-tri-3,5,5-trimethylhexanoate may be incorporated into the base composition as there is no danger of deterioration during storage due to its inert chemical nature which also provides for good compatibility with practically all perfumes, flavoring agents and pharmaceutically active substances used for application on the skin.

The novel spreading agent enhances spreading of preparations containing it. Not only does a given amount of the preparation spread wider but spreading is also faster and it is possible to get thinner but still coherent films from a given amount of the preparation than with known spreading agents used in such preparations.

If the novel spreading agent is added to base compositions the addition is done in such an amount that the final preparation contains the amounts shown earlier in this connection for the final preparations i.e. oils, creams, emulsions and ointments.

It will be obvious to those skilled in the art that various changes may be made without departing from the scope of the invention and the invention is not to be considered limited to what is shown in the drawings and described in the specification.