CONDUCTOMETRIC TESTING AND CORROSION STUDY OF HAIR SPRAY 155 200 • 200 /•o.•5 % NM -- /•0.15 % NM /L• 0.:30% NM 0.:30 % NM / ,oor / /0.15% NM 0.15% NM F/r•0.30 % NM g 0• NM •0.30% I I I I 0 I I 6 12 18 2 [ 12 18 Time (mos.} ß Time (mos:) 24 Figure 11. Veto-640 (9()• neutr. with AMPD) Figure 12. Resyn 28-1310 (90% neutr. with AMPD) The effects of various amounts of nitromethane on formulas with different resins in 93% (---) and 95% (--) by wt. ethanol. 0.15% and 0.30% o[ nitro•nethane based on Fll was used Amount of air in vapor space--approx. 8% Fill: 36% cone. with 3% of resin solids, 65% F12/ll 35/65 •200 • 200 . 0% NM I' • %NM • . ,oo % : I i / 0 6 12 18 24 0 6 12 18 24 • , Time (mos.] • Time Figure 13. Commercial formula with E-735 Figure 14. Commercial formula with Resyn 28-1310 The effects of various amounts o[ nitromethane (based on Fll) on commercial [ormulas in 95% by wt. ethanol at 48øC Amount of air in vapor space--approx. 8% Filh 35% cone. with 3% o[ resin solids, 65% F12/tl 35/65 The influence of nitromethane on inhibiting corrosion of various for- mulations containing 93% by wt. and 93% by wt. ethanol with VEM-640 and Resyn 28-1310 is shown in Figs. 11 and 1.2. Similar tests were per- formed on commercial products containing E-735 (Fig. 13) and Resyn 28-1310 (Fig. 14) resins. Distilled water and nitromethane were added to the can to obtain the desired combination of components. Before making general conclusions from these results, it must be remembered that perfume components may act as corrosion inhibitors or

156 JOURNAL OF THE SOCIETY OF COSMETIC CHEMISTS '- 200 E E • •oo I ø 2.0 40 60 80 Time (days) Figure 15. The effects of various a•nounts of water on conductivity of commercial hair spray containing Veto-640 resin without •fitromethane at 48øC. Amount of air in vapor space-- approx. 8% • 60 - o _ _ -• 20 I 2 Time (mos.) perfume A•=• ,'• perfume B 4 6 Figure 16. Comparison of the effects of two different perfumes (A and B) on the conductivi- ties of formulas containing Vem-640 resin in 95% by wt. ethanol with nitromethane at 48øC Fill: 35% cone. with 3% resin solids, 65% F12/11S 35/65 Amount of air in vapor space--approx. 8% accelerators. This fact could change the comparative corrosion rapidity between elevated and room temperatures. Figure 15 shows a case in which a particular perfume component acted as a stabilizer of corrosion, thus formulations with up to 5% by wt. of water were stable. Tests were also conducted with at least two different perfumes with all the listed hair spray resins. Figure 16 stresses that the only unpre- dieted factor in the use of formulations with 95% by wt. ethanol in com- bination with nitromethane is the possible role of the perfume as an accelerator of corrosion. For this reason, each formulation should be scrutinized individually for these effects before production filling. The effect on corrosion of different degrees of neutralization of car- boxylic types of resin in anhydrous and nonanhydrous ethanol was also studied using VEM resin. Formulas with 0 to 90% (in 10% incre-