HAIR LACQUER SYSTEMS AND THEIR EVALUATION 485 CONCLUSION At present it is impossible to foresee what effect the present investigations into toxicity and flammability hazards will have on the future development of pressurized hair lacquers. Investigations into the physiological properties of film formers may prove enlightening, and film forming products which can be metabolized readily may be developed. The present situation offers a challenge to the cosmetic industry which must be accepted. (Received: 27th February 1963) REFERENCES Shirley Inst. Mere. 9 81 (1930) J. Textile Inst. Trans. 21 380 (1930) Schimmel Briefs (January 1961) Technical Data Sheet CSL-66 (Hercules Powder Company, Wilmington, Del., U.S.A.) _PV_P Formulary (1960) (General Aniline & Film Corporation, New York, U.S.A.) Brit. Pat. 828,970 Brit. Pat. 856,403 Technical Bulletin 184 (National Adhesives, Ltd., Slough Bucks.) Brit. Pat. 796,318 Brit. Pat. 796,319 Soap, Perfumery & Cosmetics 30 1267 (1957) U.S. Pat. 2,948,656 Bergman, M., Flance, I. J., and Blumenthal, I-t.T. New Engl. J. g/led. 258 471 (1958) Rosen, S. I-t., Castleman, 13., and Lubow, A. New Engl. J. g/led. 258 1123 (1958) Edelston, G.H. Lancet 2 112 (1959) Calandra, J., and Kay, J.A. Proc. Sci. Sect. Toilet Goods Assoc. 30 41.44 (1958) Draize, J. I-t., Nelson, N. A., Newburger, S. I-t., and Kelley, E.A. Proc. Sci. Sect. Toilet Goods Assoc. 31 28 (1959) Bergmann, M. et al New oengl. J. Med. 266 750 (1962) Schepers, G. W. H. ,f. Am. Med. Assoc. 181 635 (1962) Brit. Pat. 868,879 Aerosol Guide 11 (C.S.M.A., New York, U.S.A.) Felton, R. A., and Yeomans, A.H. Aerosol Age 8 18 (January 1963) C.S.M.A. Bulletin 84-62 (16th April 1962) Kempe, W. Aerosol Age 8 28 (January 1963) Sanders, P.A. Chem. Specialties Mfrs. Assoc. Proc. 66 (May 1960) Bower, F.A. Chem. Specialties Mfrs. Assoc. Proc. 57 (May 1961) Bower, F.A. Chem. Specialties Mfrs. Assoc. Proc. 49 (May 1962) Johnsen, M.A. Aerosol Age 7 29 (July 1962) Johnsen, M.A. Aerosol Age 7 39 (August 1962) Garton, L.M. Aerosol Age 7 108 (October 1962) Gunn-Smith, R. A., and Platt, N.E. Aerosol Age 6 33 (February 1961) Introduction by the lecturer The pressurized hair lacquer is the subject of more controversy than any other pressurized product. Toxicity and flammability hazards are the subject of critical investigation in many countries. It has been the

486 JOURNAL OF THE SOCIETY OF COSMETIC CHEMISTS subject of more commercial failures than any other pressurized product, which have been due to a variety of causes, including corrosion of the container, deterioration of the product, incompatibility of the product with the propel!ant, valve failure through blockage, gasket hardening, and the failing off of the dip tube. I would therefore like to stress the necessity for exercising rigid quality control of incoming raw materials, components, and of manufacturing and filling operations. The alcohol and film formers must be handled with extreme care to prevent the uptake of water. Most of them, as supplied, contain a small and unavoidable amount of water. These amounts are not serious, but careless storage, processing, and filling can increase them to dangerous levels. The water content of the finished pack is critical, and may contribute to product deterioration and container failure. Compatibility tests should be carried out on every incoming batch of raw materials, in addition to routine analyses for water content, etc. This is particularly important with shellac. Where cold filling operations are carried out, the minimum temperature to which the concentrate can be chilled without throw-out of the resins and other ingredients, should be carefully established, and plant control should be such that the concentrate is not chilled below this level. If aluminium containers are used, then the integrity and efficiency of the lacquer system should be investigated most carefully. Routine tests, such as checks on the seams of tinplate containers, neck dimensions, and container strengths, must also be carried out. Apart from general valve quality control, particular attention should be paid to the effect of the formulation on the rubber valve gasket. Since the hair lacquer formulations are active stress-raising agents, the possibility of environmental stress-cracking of the polyethylene dip tube used on each batch of valves must be checked. The interference fit constituted by the pushing of the end of the dip tube over the tailpiece of the valve housing in some valves creates a multi-axial stress system which may, especially if active stress-raising ingredients are present in the pack, result in longitudinal splitting of the polyethylene in this region, causing the dip tube to fall off the housing, and the pack to be useless. This has actually happened. A suitable test method is to immerse the assembled dip tube and valve housing in a 2.5% solution of nonyl phenol ethylene oxide condensate (Lissapol NX), for 24 hours at room temperature. If no splitting occurs in the region of mating of the dip tube and valve housing tailpiece, the valves should be satisfactory for most conventional hair lacquer formulations. If, however, splitting does occur, then the valves must be rejected, re-tubed,