SKIN SMOOTHNESS AND SKIN SOFTNESS 115 Weinstein and David Canestrari, and the author wishes to express his gratitude to them. REFERENCES (1) I. H. Blank, Factors which influence the water content of the stratum comeurn, J. Invest, Dermato/., 18, 433(1952). (2) N. Orentreich and N. P. Durr, "Epidermabrasion: Physical Mechanical Abrasion of the Epidermis," A scientific exhibit at 3 3 rd annual meeting, Amer. Acad. Dermatol., 1974, Chicago, Illinois. (3) G. Imokawa, K. Sumura and M. Katsumi, Study on skin roughness caused by surfactants: I. a new method in vivo for evaluation of skin roughnes s, J. A mer. Oil Chem. Suc., 52, 479( 1975). (4) G. Imokawa, K. Sumura and M. Katsumi, Study on skin roughness caused by surfactants: II. correlation between protein denaturation and skin roughness. J. Amer. Oil Chem. Soc., 52,483(1975). (5) G. Imokawa and T. Takeuchi, Surfactants and skin roughness, Cosmetics and Toiletries, 91, 32(1976). (6) R. Marks and A.D. Pearse, Surfometry, a method of evaluating the internal structure of the stratum corneum, Brit. J. Dermatol., 92, 651(1975). (7) J. K. Prall, Instrumental evaluation of the effects of cosmetic products on skin surfaces with particular reference to smoothness, J. Soc. Cosmet. Chem., 24,693(1973).

j. Soc. Cosmet. Chem., 29, 117-125 (March 1978) Low-energy emulsificationl principles and applications T.J. LIN 628 Enchanted Way, Pacific Palisades, CA 90272. Received February I O, 1977. Presented at An nual Meeting, Society of Cosmetic Chemists, December 1976, New York, New York. Synopsis The amount of energy normally expended in commercial processing of a cosmetic emulsion is far greater than the amount theoretically required. Whether the emulsion is made by a batch process or semicontinuous process, thermal energy is first supplied to heat the ingredients and mechanical energy is then provided for mixing and emulsification. Additional mechanical energy is expended to cool the product and the heat removed is generally discarded. A considerable saving in energy is made possible by a more effective usage of thermal and mechanical energy in emulsification. A substantial saving of thermal energy can be achieved by a careful determination of emulsification temperature and by a selective heating of the ingredients. The method discussed here basically involves making an emulsion concentrate which is later diluted with the remainder of the external phase at room temperature. In addition to conserving energy, the proposed LOW-ENERGY EMULSIFICATION technique also offers a great advantage in reducing the processing time and equipment cost. In some instances, the energy cost for processing an emulsified lotion can be reduced by 50 per cent while the production efficiency can be increased by 100 per cent. INTRODUCTION The recent natural gas shortage in the United States has again clearly demonstrated the importance of energy conservation. One area of cosmetic processing that has not been critically examined in terms of energy requirement is emulsion processing. Compared to the energy actually required, a considerable amount of energy is wasted in a typical plant operation of emulsion manufacturing. In 1965, the author proposed a technique of emulsification referred to as "semicold processing" that was designed to allow manufacturing of emulsion products with a partial heating of the raw materials (1). Since then, the author has tested this technique on numerous emulsified and nonemulsified products in production scale with favorable results. The method allows not only a conservation of thermal and mechanical energies, but also a substantial increase in manufacturing efficiency and a reduction in operating expenses without any compromise in the product quality. In some cases, it is also possible to reduce the capital expenditure on process equipment when planning an expansion of production capacity. The main purpose of this paper is to outline the basic 117