The present invention relates to hair thickening and conditioning compositions, and in particular to aqueous gelatin solutions, the application of which to the hair results in a significant increase in hair shaft thickness. The present invention also relates to methods for preparing the gelatin compositions of the present invention, as well as to methods for increasing hair shaft thickness by topical application to the hair of the gelatin compositions of the present invention.
U.S. Pat. No. 4,749,684 discloses that the ingestion of gelatin promotes an increase in the linear growth rate of hair. Scala et al., Nutr. Rep. Int., 13(6), 579-92 (1976) discloses that dietary supplementation with gelatin produces an increase in hair thickness. The ability to increase hair thickness by the topical application of gelatin is unreported.
Hair coated with gelatin is difficult to comb in the absence of a conditioning agent, but stable solutions of gelatin with a conditioning agent have been heretofore unknown. Lindo et al., "Hair Processing and Conditioning," Hum. Hair Sym. [Pap.], 1st, (Brown, Editor, MEDCOM Press, New York 1974 (Meeting Date 1973)) pages 135-44 reports the capability of hair to absorb topically applied hydrolyzed gelatin, but with little substantivity, so that little gelatin remains after thorough washing with room temperature water.
U.S. Pat. No. 4,208,402 discloses a topical solution for improving the appearance of oily hair or skin, including the scalp, containing from about 0.5 to 1.5% by weight of gelatin and from 0.15 to 0.45% by weight of partially hydrolyzed polyvinyl acetate in aqueous or hydroalcoholic solution. The level of film-forming polymer disclosed is insufficient to provide a readily combable product. By the manufacturing process disclosed, aqueous solutions cannot be formed with higher concentrations of the film-forming polymer without the gelatin precipitating from the solution.
Topical application of gelatin to hair would be possible if stable aqueous solutions containing higher concentrations of film-forming polymers could be prepared. The inability to comb hair to which gelatin solutions have been topically applied has prevented the recognition that topical gelatin application increases hair shaft thickness.
There remains a need for stable aqueous gelatin solutions containing higher levels of film-forming polymer to provide gelatin solutions for topical hair application that do not resist combing.