]. Soc. Cosmet. Chem., 23, 125-131 (February 3, 1972) Amino Alcohols for Neutralization of Carboxylic Resin STANLEY BOHAC, M.S. • Presented May 24-25, 1971, Seminar, Washington, D.C. Synopsis--Different types of AMINO ALCOHOLS are evaluated as the NEUTRALIZATION agents for VEM CARBOXYLIC HAIR SPRAY RESIN. Variation in HYGROSCOPICITY with different relative humdity of amino alcohols themselves is compared with hygroscopicity of the resin neutralized with these amino alcohols. Effect of amino alcohols on pH value and Sward Hardness of neutralized resin is also determined. INTRODUCTION 2-Amino-2-methyl-l,3-propanediol* (AM PD) is the base most o[ten used to obtain water solubility of carboxylic-type hair spray resins. This amino alcohol was recommended [or the widely used resin--National Starch 28-1g10-* (1, 2)--and this is probably the reason why other car- boxylic resins, which became available later, assumed the use of this base. The purpose o[ this study is to evaluate other arnino alcohols and to determine i[ they can also be used as neutralization agents for carboxylic hair spray resins. National Starch resin 28-1g10 has limited solubility in anhydrous ethanol and [or this reason AMPD was chosen this base gives the highest alcohol solubility to the neutralized resin, in comparison with other amino alcohols. Other hair spray resins which are completely soluble in anhydrous ethanol do not have this requirement and thus it should be possible to use different amino alcohols. * Barr-Stalfort Co., Niles, Ill. tCommercial Solvents Corp., New York, N.Y. •National Starch Corp., New York, N.Y. 125

126 JOURNAL OF THE SOCIETY OF COSMETIC CHEMISTS This study was conducted with VEM resin* (3), a terpolymer of N- vinyl pyrrolidone, an acrylic-type ester, and acrylic acid (4), and the following amino alcohols were selected as the neutralization agents: AM PD--2-amino-2-methyl- 1,3-propanedioF AE PD--2-amin o-2-e thyl- 1,3-propane diol* AMP--2-amino-2-me thyl-l-propanol* AB--2-amino- 1 -bu tanol t MEA--monoethanolamine* D EA--die thanolamine* TEA--triethanolamine* MIPA--monoisopropanolamine* D I PA--diisopropanol amine* TIPA--triisopropanolamine* Properties of VEM resin (neutralized with these amino alcohols), such as pH value in ethanol solution, Sward Hardness, ethanol solubility, and hygroscopicity, were evaluated. Also, the hygroscopicity of the pure amino alcohols was determined. EXPERIMENTAL Values of pH in ethanol solution were determined in a way com- monly used in the aerosol industry. A pH meter, equipped with glass- calomel electrodes, was standardized with aqueous buffer solution, in this case, at pH 9.18. Then the pH value of the particular ethanol solution was determined. The hygroscopicity of VEM resin neutralized with different amino alcohols and also the hygroscopicities of pure amino alcohols were de- termined in a modified Blue M humidity chamber.• Relative humidity was varied from 65 up to 9270 at constant temperature 30øC (86øF). The instrument used, as well as the method, was described in another article (5). Sward Hardness was determined at room temperature (23øC) using the Sward Hardness rocker (5). Purity of the amino alcohols was de- termined by conductometric titration (6) and hy•oscopicity data were obtained by weight increase in the modified Blue M humidity chamber with approximately 1-g samples after 72 hours under constant conditions. *Barr-Stalfort Co., Niles, Ill. tCommercial Solvents Corp., New York, N. Y. *Union Carbide Corp., New York, N.Y. õBlue M Co., Blue Island, Ill.