HAIR WAVING AND STRAIGHTENING PRODUCTS

Composition and Function:

Hair waving and straightening products alter the configuration of the hair while it is being maintained in a curled position or being combed or stretched.

Modern curling of hair follows a sequence of three essential steps: (1) wrapping the hair on a proper curler; (2) softening or swelling of hair with an alkaline chemical agent; and (3) neutralization of the softening agent with a mild oxidizing solution or by air oxidation. The neutralization step hardens or sets the hair so that it retains the new curled condition when removed from the curler. Air oxidation is a much slower process and is the process used in the "no-neutralizer" permanent waves.

The function of the waving solution is to swell and soften the hair. Human hair is composed of keratin, a typical protein consisting of elongated molecules of condensed amino acids. Cystine cross linkage, the basis of hair fiber, is responsible for most of the properties of the hair. The cystine molecule consists of two amino acid groups linked together by two atoms of sulfur. The waving solution acts by breaking this disulfide linkage while the hair is on the curlers.

Thioglycolates are the reducing agents of choice used in hair waving products. While various thioglycolates, including the acid itself, have been used, ammonium thioglycolate seems to be preferred. Commonly used cold wave solution formulations are of two general types and are based on ammonium thioglycolate or ammonium thioglycolate with monoethanolamine. 8.0-8.5% solutions are used for hard-to-wave hair, 6.5-7.5% for average hair and 4.5-5.5% for dyed or moderately damaged hair.

The effective pH for thioglycolate waving solutions is 9.2-9.3 using ammonia as the alkaline source. Clouding agents are included in the majority of cold wave lotions for either esthetic, wetting or conditioning properties. Both resins and oil emulsifiers may be used at a 1% level.

Surfactants may be included as opacifiers, thickeners, wetting agents or solubilizers. The levels may vary from 0.5% to very high concentrations. Nonsaponifiable surfactants such as the BRIJ(r) products are preferable, but TWEEN(r) series and ARLACEL(r) series surfactants have been used.

The neutralizers used in cold wave processes are dilute aqueous systems containing sodium perborate, sodium or potassium bromate, hydrogen perocide and sodium or potassium tetrathionates. These mild oxidizing agents will cause a hardening or setting of the curl in five to fifteen minutes. Twenty volume peroxide is used professionally while neutralizer liquids for home use will contain 10%-15% of the perborate, bromate or tetrathionates.

Hair straightening products are closely related to waving products. Quite often the same process is used to straighten the hair as is used to curl it. While most modern hair waving is accomplished by chemical means, hair straightening today is still accomplished by physical means and the use of alkalinity as well.

Physical straightening employs the use of pressing oils applied hot while the hair is being combed or stretched straight. Pressing oils generally contain waxes, perfume, lanolin and other hair conditioners in a petrolatum base.

The alkali type of straightener is used primarily by men, where straightness is desired and no styling required. Sodium hydroxide at levels ranging from 1% to 10% is used in these cream products to reduce the cystine content of the hair. A relaxation in the hair fibre results. These creams will contain thickeners such as stearyl or cetyl alcohols in a total concentration of 15% to 25% for viscosity control, 5% mineral oil or other conditioners is included in many formulations. Surfactants will be present for emulsification and wetting characteristics.

Hair straighteners are preferably based on ammonium thioglycolate, usually neutralized with a perborate or bromate. They are similar to cold wave formulations but with a lower pH and a lower ratio of free ammonia to thioglycvolate. A typical products for average hair will contain around 7% thioglycolic acid (present as the ammonium salt) at pH9. A typical formula for any fine hair will contain 5% thioglycolic acid (as the ammonium salt) at pH 8.8. Hair straighteners may be formulated as creams using appropriate thickeners, emulsifiers, wetting agents, and conditioners.

Hair waving and straightening products can produce unpleasant odors in the course of ordinary use. FORESTALL™ Soyaethyl Morpholinium Ethsulfate is a deodorizer which is particularly effective against these types of volatile sulfur compounds. At levels of 0.5% (active) in permanent wave and/or neutralizing lotions, FORESTALL markedly reduces malodors during and after the perm. FORESTALL is also a highly effective cationic hair conditioner which improves wet combability and leaves hair well conditioned.

Formulation:

One obvious application for FORESTALL is in home permanents as a deodorizer/conditioner. The following example is a basic formula without optional ingredients like opacifiers or thickeners.

Preparation:

Mix (A) with gentle heat if necessary until uniform. Add (B), Add (C), Adjust pH to 9.0-9.5 with additional ethanolamine or thioglycolic acid.

Preparation:

Mix (A) with gentle heat until uniform. Add (B) at 25°C. Adjust pH to 4.5-5.0 with (C). Optional stabilizers may include sequestrants or antioxidants.

Hair straighteners contain essentially the same ingredients as waving preparations, but they are considerably more viscous. The added viscosity aids in holding the hair in a straightened position during softening.

Formula HC-17 typifies modern hair straightening creams. Sodium hydroxide is the alkaline agent which alters keratin.

Preparation:

Heat (A) to 60°C. Add (B) to (A) with constant agitation until cool. Add (C). Mix thoroughly.. Add (D). Replace water lost by evaporation.

A typical bromate neutralizing lotion is represented by Formula HC-18. Viscosity is controlled in the system by blending surfactants.

Preparation:

Add the sodium bromate to water. Stir with heat until dissolved. Add the remainder of (A). Heat to 70-75°C. Agitate continually until cooled to room temperature. Adjust pH to 6.5-7.0 with (B). Replace water lost by evaporation. Package.