Creative Developments (Cosmetics) Limited

Hair Styling 1996

Using a preparation to control the appearance of hair is as old as man himself; at first it was probably animal fat, then an emulsified version and eventually hair cream, bay rum and brilliantine while for the ladies there were various gums and shellac lacquer. Then came Polyvinylpirrolidine in solution or aerosol form, followed by hair sprays based on Polyvinylpirrolidine/Vinyl Acetate combinations and Vinyl Acetate /Crotonates Copolymer. Hair gels made a brief appearance in the early sixties, disappeared for 20 years then came back to stay. Over the last decade aerosol preparations have concentrated on changing the propellant from fluorocarbons to hydrocarbons and then on reducing the VOC content while pump action sprays have established their own market niche. The CTFA list over two hundred film formers but less than sixty are also described as hair fixatives and probably only half that number are of significant importance. Despite technical advances Sterculia urens (karaya gum), Astragalus gummifer (gum tragacanth) and shellac are still in common use today while petrolatum satisfies a huge Afro hair market.

The ideal fixative allows the hair to flow naturally while remaining in style, resists high humidity while not being brittle and is easy to comb, conferring a good gloss and being readily washed out while not flaking onto the shoulders like a bad attack of dandruff when being dry combed later in the day. Besides trying to satisfy these criteria the main developments have been in the spray forms and in overcoming the problems of providing a strong hold with minimum product viscosity for low pressure propellants and pump sprays.

A short review of the most popular resins will help illustrate the properties sought in a good hair styling product. Polyvinylpirrolidine (PVP) was one of the first polymers used but because it is water soluble it absorbs atmospheric moisture, becoming sticky and unsuitable as a fixative. Vinyl acetate (VA) is insoluble in water but dries to a brittle film; copolymers of PVP/VA vary from 70:30 to 30:70 PVP:VA so a complete range of properties is possible. Solution viscosities are too great for low pressure aerosols and pump sprays but careful selection of the PVP/VA ratio enable the formulator to pick the right combination for hair gels and setting lotions. Altering the PVP:VA ratio is one way of modifying fixative properties, many others require neutralising before use and the degree of neutralisation can have a dramatic effect, allowing the formulator the opportunity to achieve exactly the desired end-result. One such well known material is a VA/Crotonates/Vinyl Neodecanoate Copolymer, National 28-2930, from National Starch & Chemical Company. It is a carboxylated vinyl acetate terpolymer and the carboxyl groups may be neutralised by various aminohydroxy compounds such as AMP (2-amino-2-methylpropan-1-ol, DEPA (diethylamino proplyamine) or TIPA (triiso propanolamine). Film characteristics are influenced by the type as well as the amount of amino compound used and the manufacturers provide detailed graphs which illustrate the effects of degrees of neutralisation, of using combinations of neutralisers and of incorporating water in the final product. Not only is film hardness and water-resistance altered but also solubility in hydrocarbon propellants and the need for plasticers is dependent on the neutraliser used and the final pH of the product. If 28- 2930 is completely neutralised by a strong alkali it becomes water soluble and is said to provide a fine, misty spray with rapid drying in low VOC formulations containing up to 20% water. A more recently introduced material under the Amphomer trade name from the same company is Octylacrylamide/Acrylates/Butylaminoethyl Methacrylate Copolymer, an amphoteric acrylic polymer described as a stiff resin conferring outstanding curl retention in all temperature and humidity conditions. Relatively low levels may be used for a soft, easy hold with good sprayability, ease of combing, good solubility and ease of removal upon shampooing.

From BASF is Ultrahold 8, an anionic Acrylates/Acrylamide Copolymer compatible with the commercially available propellants propane/butane, isobutane, dimethyl ether and their mixtures over a wide range of concentrations. 3% solutions in absolute ethanol neutralised with 0.35% AMP will tolerate 50-55% propane/butane and have a cloud point below -15^o C. BASF have also added an Acrylates Copolymer to their Luvimer range which is claimed to be particularly suitable for low VOC products. Other anionic polymers include the pre-neutralised Diahold range from the Mitsubishi Chemical Corporation. and distributed through Clariant Corporation. They are AMP-Acrylates Copolymers giving a low solution viscosity and are compatible with propellants including dimethyl ether. From the same source is Methacryloyl Ethyl Betaine/Acrylates Copolymer, an amphoteric polymer with a carboxylic betaine structure which improves hair substantivity, giving a uniform, flexible film and a natural hold and feel. There are a number of variants available for different applications and extensive product literature describes these plus efficacy tests and the effects of changing various parameters on solution viscosity, curl retention etc.

A range of Alkyl Esters of PVM/MA Copolymers, the Gantrez materials from International Specialty Products, were one of the first fixatives to be introduced specifically for pump sprays. Different alkyl groups are available and again, properties may be adjusted by altering the degree of neutralisation. Also from ISP is Vinyl Caprolactam/PVP/Dimethylaminoethyl Methacrylate Copolymer, a water-soluble resin supplied as H₂OLD EP-1 and suitable for alcohol-free and low VOC sprays. An Acrylates/Hydroxyesters Acrylates Copolymer, Acudyne™ 255 Hair Fixative from Rohm & Haas, is a low viscosity liquid which is used for producing low VOC products. It has a wide solubility range in hydroalcoholic and aqueous systems yet is non-tacky and gives high curl retention, even under very humid conditions. Being water-soluble the polymer is readily removed by shampoo, is non-flaking upon dry combing and gives an excellent spray pattern, even in high water content products. It is claimed to be non-hygroscopic, quick drying and does not clog spray nozzles.

.The fixative resins so far described are polymers which are in solution in the product. When the solvent is ethanol or isopropanol they provide excellent results but can fall short of expectations in low VOC products. Water dilutes the holding power, spray pattern and quick-drying properties that hair sprays are meant to have. A different approach is to provide the polymer as a dispersion or emulsion. An example is an Acrylates Copolymer, Amerhold DR-25 by Amerchol, which, claims the supplier, with dispersion polymers, the small, solid polymer particles are suspended in water and will not settle out. Surfactants coat the surface of the polymer particles and act as stabilisers. These surfactants prevent the particles from sticking together as they continuously collide with neighbouring particles. Each polymer particle is packed with polymer molecules and surrounded by other polymer particles. The polymer molecules at the surface of the particle are exposed to a liquid (water) in which they do not dissolve. A similar approach from Eastman has resulted in the Eastman AQ Polymers, INCI name Diglycol/CHDM/Isophthalates/SIP Copolymer, described as sulfonated polyesters they are water-dispersible with excellent humidity resistance and fast setting times. They do not require neutralisation and have low viscosity at 30% solids and below which eases formulation. However viscosity increases rapidly above a 30% solids level so that in use, as the solids level increases because of water evaporation, the dispersion becomes so viscous that it begins to behave as a solid. This results in very rapid hold, even before drying is complete. Conversely, the dried film must absorb a significant amount of moisture from the atmosphere before the "hold" properties of the product are adversely affected.

A look through recent patent applications confirms the trend towards low VOC products; a patent granted to National Starch describes the use of a natural based hydrolysed zein fixative¹ while another from the same company claims the use of hair fixative carboxylated polymers stabilised by neutralisation in an aqueous emulsion which require minimal organic propellant when dispensed in aerosol containers². ISP were granted a patent for an 80% VOC, single phase aerosol hair spray composition with a minimum of 15% hydrocarbons as propellant plus a small amount of dimethyl ether as cosolvent to assure solubilisation of the hair fixative resin, alcohol, water and hydrocarbon components of the composition within a single phase³. ISP also claimed a microemulsion of a water-insoluble polymers with a particle diameter of less than 1 micron⁴.

Procter & Gamble were granted a patent for hair styling compositions containing a silicone grafted polymer characterised by an organic polymeric backbone with silicone macromers grafted to it⁵. The organic polymer backbone is soluble in polar solvents while the silicone macromers are soluble in hydrocarbon propellants. The polar solvent is water plus approximately 15% by weight of ethanol and the hydrocarbon solvent is less than 15% of the total, the use of acetyl triethyl citrate as a plasticiser is said to improve the product. Cheseborough-Ponds applied for a an aqueous hair treatment composition that includes a water-soluble polymer having a solution viscosity at 10% in water of less than about 20,000 cps at 25 deg. C., and a latex of water-insoluble polymeric particles of less than 3 micron diameter dispersed in water⁶.

Not all hair styling products are spray-ons; there are mousses, gels, lotions and creams. These alternatives to the ubiquitous spray enable different properties to be built into the formulation. Thus Polyquaternium-4, Celquat H-100 from National Starch, is a cationic cellulose polymer substantive to skin and hair which can act as an effective and substantive thickener. In mousses, setting lotions, gels and conditioners, it provides excellent combability, holding, gloss and antistat properties. A cationic aqueous solution of a copolymer of diallyl dimethyl ammonium chloride and acrylamide is sold as Salcare SC-10, Allied Colloids, while from the same source Salcare SC30 is a cationic aqueous solution of a diallyl dimethyl ammonium chloride homopolymer. Both materials may be added to hair mousse and styling gels to improve hold, condition and shine. ISP has a number of cationic Gafquats which may be advantageously added to gels, mousses and glazes and the cationic Luviquat FC 370 from BASF, may be added to a styling gel to improve conditioning action.

1. US Patent 5,518,71; 21/05/96, National Starch and Chemical Co., Hydrolysed zein as hair fixative in hair compositions

2. US Patent 5,501,851; 23/03/96, National Starch and Chemical Co., Emulsion polymers for use in hair fixatives

3. US Patent 5,435,993; 25/07/95; ISP Investments Inc., 80% VOC, single phase aerosol hair spray composition.

4. US Patent 5,458,871; 17/10/95; ISP Investments Inc., 0% VOC, single phase aerosol hair spray composition.

5. US Patent 5,565,193 15/10/96; Procter & Gamble, Hair styling compositions containing a silicone grafted polymer and low level of a volatile hydrocarbon solvent.

6. US Patent 5,441,728 15/08/96; Chesebrough-Pond's Co, Hairspray compositions