HAIR LACQUER SYSTEMS AND THEIR EVALUATION 475 vI PVP ........ Lanolin derivative .... Diethyl phthalate .... Silicone fluid ...... Perfume ........ Industrial Methylated Spirits 74 o.p. Propellent 12 ...... 2.3s% 0.30% o.6s% 0.30% o.5o% 60.90% 35.00% Vinyl Pyrrolidone/Vinyl Acetate Copolymers (PVP/VA) The copolymers of vinyl acetate with vinyl pyrrolidone 6 have film form- ing properties similar to PVP, but the vinyl acetate confers a greater degree of water resistance and reduces the solubility in water. The 60/40 vinyl pyrrolidone/vinyl acetate copolymer is commercially available. Although the PVP/VA films are less hygroscopic than PVP, they are, nevertheless, still somewhat hygroscopic and the addition of modifying agents similar to those used for PVP is necessary. The copolymers films are stiffer than corresponding PVP films, but additional film formers such as shellac, DMHF resin or ethyl cellulose may be added, as with PVP. Hair lacquer formulations based on PVP/VA are of a similar type to those in which PVP is used. Vinyl Acetate Copolymer An acidic vinyl acetate copolymer, National 28-1510 ?, provides a resin which can be modified, by neutralisation with bases, to give films of differing degrees of flexibility and sensitivity to water. The preferred base is 2-amino- 2-methyl-I, 3-propanediol and as the degree of neutralisation increases, the films produced become softer and more water-soluble. 85--95% neutrali- sation of the theoretical acidity produces a film of suitable characteristics. The following formulae are suggested as a basis for experiment • :-- VII National 28-1810 .... 2-amino-2-methyl-1, 3-propanediol Alcohol soluble lanolin .... isoPropyl myristate (cosmetic grade) Dipropylene glycol .... Perfume oil ...... SDA-40 alcohol (anhydrous) .. 3.45% 0.38% 0.90% 0.40% o.o% 0.35% 94.42%

476 JOURNAL OF THE SOCIETY OF COSMETIC CHEMISTS VIII National 28-1510 .... 2-anfino-2-methyl-1, 3-propanediol Water soluble lanolin .... Silicone 555 ...... Perfume oil ...... SDA-40 alcohol (anhydrous) .. 2.40% 0.22% O. lO% O. lO% 0.40% 96.78% Fill: 30% Concentrate 70% Propellant mixture Acrylic Resins Acrylic resins modified so that they are soluble in water, and suitable for hair lacquers, are described in two patents 9'xø. The films have the clarity characteristic of this type of resin, are not hygroscopic, and are compatible with a wide range of plasticizers, lanolin derivatives and silicone fluids. A typical formula is :-- IX Modified acrylic resin .... Alcohol soluble lanolin .... Silicone fluid ...... Perfume ........ Industrial Methylated Spirits 74 o.p. Propellant 12/11 (50: 50) .. 2.0% o.•% o.1% o.s% a7.a% 60.0% Dimethyl Hydantoin Formaldehyde Resin (DMHF) DMHF is a clear resin, soluble both in alcohol and in water, and gives a film which is slightly hygroscopic. It is compatible with other film formers including shellac, ethyl cellulose, PVP and PVP/VA copolymers. Lanolin derivatives and silicones may be incorporated into DMHF lacquers, and suitable plasticizers include polyethylene glycol 400 monolaurate, phthalates and glycols.