US2102712A - Protective cosmetics - Google Patents

Description

Patented Dec. 21, 1937 PATENT OFFICE PROTECTIVE COSMETICS Samuel Isermann, Summit, Ernst Ohlsson, Jersey City, and John W. Orelup, Summit, N. J.

No Drawing. Application January 4, 1935,

Serial No. 426

5 Claims.

Our present invention relates to improvements in protective cosmetics. It is well known that over-exposure of the body to direct radiation from' between 2900 and 4500 Angstrom units, is very high, amounting to 17% of all the radiation received. The intensity of the region below 2900 amounts to only 1.8%.

Heretofore, workers in the art have been handicapped by the lack of satisfactory means for quantitativelymeasuring the screening effect of thin films of active materials so that the use of substances heretofore proposed has been based largely on theoretical grounds, it being assumed that those substances which show absorption in the ultra violet region would be practical for the purpose of protecting the skin.

We have devised such a means whichcomprises a filter, such as fused calcium phosphate colored with oxides of nickel and cobalt, which admits only physiologically active rays and rejects the visual and infra red rays. The radiation thru this filter is then measured by means of a suitable photo-electric cell, as for example, a copper oxide cell, connected to a highly sensitive microammeter of low internal resistance.

To test a given substance it is merely necessary. to spread a thin film of the same on the filter, expose the coated filter to the sun and record the reading which is thereupon compared with a reading obtained under the same conditions without the film and in this way a percentage value obtained. The readings of the microamrneter are directly proportional to the intensity of the ultra violet radiation of wave lengths 2900 to 4000.Ilngstrom.

By employing this test, it has been found ,that many substances which have heretofore been proposed, such as benzyl cinnamate, benzyl salicylate, menthyl salicylate, aesculetine, salts of quinine, and umbelliferon, although on theoretical grounds capable of a substantial amount of ultra violet absorption, are practically valueless tensity of the ultra violet in the sun radiation.

when used in a thin film even in concentrations in excess of what could be tolerated by the skin. Thus, in the undiluted state, menthyl salicylate shows only absorption of the ultra violet, 1 benzyl salicylate undiluted 17%, benzyl cin- 5 namate 20%.

As can be seen the use of these compounds would be of no appreciable benefit; moreover, the concentrations required even for this small degree of absorption are too high for practical 10 use. Coating the body with undiluted substances of this type would cause serious physiological disturbances.

After examining a large number of substances, we'have found that in thin films even extremely small quantities of amino and substituted aminoortho-benzoic acids have the remarkable property of absorbing from 50% to 80% of the ultra violet radiation of the sun in the region between 2900 and 4000 Angstrom. Percentage concentrations which are effective are as low as .01%. Of course, larger concentrations may be used, for example, up to 5%. In most cases for an 011 type cosmetic it is necessary to form an oil soluble derivative. This oil soluble derivative may be 5.

produced by uniting the active ingredient with a fatty acid, as for example stearlc acid or oleic acid or mixtures thereof.

An advantage of our improved compounds is that they are substantially odorless and colorless. The compounds substituted in the amino group are practically odorless in contradistinction to those compounds substituted in the carboxyl group which are strongly odorous. The active ingredient which we prefer is benzylamino-ortho-benzoic acid. Also effective are the methyland di-methyl-amino-ortho-benzoic acids; the butyl, propyl, amyl, and higher derivatives: as the lauryl, myristyl, cetyl compounds.

The following examples illustrate the invention:

A 1% solution of dimethyl amino-benzoic acid is formed in 20% almond oil and 80% mineral oil with color and perfume to suit.

III

' Ortho-amino-benzoic acid stearate is prepared as follows: 14 lbs. ortho-amido-benzoic acid is' 5 melted with 30 lbs. stearic acid heated to 80 C. until mass is homogeneous. The product is cooled and pulverized. A 2% solution is thereupon region between 2900 degrees and 4000 degrees Angstrom when, said active ingredient is present in an amount not substantially greater than 5%. 4. A cosmetic effective in thin films to retard ultra violet absorption containing as an active ingredient a fatty acid compound of an amino or substituted amino-ortho-benzoic acid in an oily vehicle in concentrations of less than 5%.

5. A cosmetic eilective in thin flims to retard ultra violet absorption containing as an active ingredient an amino or substituted amino-orthobenzoic acid in an oily vehicle in concentrations of less than 5%.

SAMUEL ISERMANN. JOHN W. ORELUP. ERNST OHLSSON.