./. 5'o•. Cosmeh'• Chc./isis, 17• 595 605 (196(i) Hygroscopicity and Hardness ooe Hair Spray Resins at Varying Humidities MORRIS 3. ROOT, M.S., and STANLEY BOHAC, M.S.* Presented May 10, 1988, New York City Synopsis--An apparatus is described for •neasuring moisture pick-up, drying rate, and Sward Hardness of various resin films at relative humidities of from 50 to 90%. Data are given on films laid down from anhydrous SDA #40 ethyl alcohol. Resins used include: Polyvinyl Pyrrolidone (PVP K-30), Vinylpyrrolidone/Vinyl Acetate Copolymer (PVP/VA 735), VEM © Resins, 90, 50, and 0% neutralized with 2-mnino-2-methyl-l,3-propanediol (AMPD), and National Starch Resyn © 28-1310, 90, 70, and 0% neutralized with AMPD. One set of data uscd the unplasticizcd films, and a second set used thc film plasticized with 3.5% DC-555 Silicone Oil. Although this apparatus has been useful for collecting data on resins used in hair sprays, the method and apparatus can be used for obtaining data with these and other resins for applications such as adhesives and coatings. INTRODUCTION There has been a noticeable lack of data comparing moisture pick-up and hardness of hair spray resin films at various humidities. What little data are available have been on work that was done only with one type of resin by the manufacturer using a method not fully described. One Technical Service Bulletin (1) shows the water absorption rate of Resyn©t 28-1310, neutralized 125, 90, and 0% with 2-amino-2-methyl- 1,3-propanediol (AMPD), for periods of up to 160 hours. A patent (2) assigned to National Starch gives the Sward Hardness of Resyn 28-1310 * G. Barr Co., Niles, Ill. 60648. '• Resyn is a registered trademark of National Starch and Chemical Corp., Resin Division, New York, N.Y. 595

JOURNAl, OF THE SOCIET\' OF COSMF. TIC CItEMISTS Figure 1. Controlled humidity chamber neutralized to varying degrees with several different amino-alcohols. Sward Hardness values range from 44 down to 14, starting with un- neutralized resin and going up to 130% of the theoretical equimolar amount of copolymer reacted. Another Technical Service Bulletin (3) describes the hardness of Resyn 28-1310 at varying degrees of neutraliza- tion with four different amino-alcohols. This bulletin also shows the moisture content at equilibrium with 50 to 91}% relative humidity of Resyn 28-1310 films neutralized to 100, 80, and 60% with AMPD. These films were cast from solutions in anhydrous SDA-40 ethyl alcohol. The hygroscopicity of PVP K-30* (4) and PVP/VA (5) has been re- ported at relative humidities ranging from 30 to About the only work comparing various resins using the same method was done in Japan (6). VEM©• -640, -645, and --649, PVP K-30, * PVP K-B0 and PVP/VA, Antara Chemicals, I)ivisi(m •f General Aniline and Fihn Corp., New York, N.Y. } VEM is a registercd trademark of G. Barr Co., Division of Pittsburgh Railways Co., Niles, I11.