Silica Gel

Silicone: The Basis of a Perfect Formulation for Hair Care
Adriana Urrutia Dow Corning de Mexico S.A. de C.V.

Adriana Urrutia

Silicone: The Basis of a Perfect Formulation for Hair Care
Adriana Urrutia Dow Corning de Mexico S.A. de C.V.

Abstract
The needs of today’s consumers have led cosmetics formulators to look for new alternatives to help treat the hair after exposure to externalagents such as the sun, combing, and drying as well as chemical products such as permanents and dyes. A major objective has been to develop formulations using ingredients that provide a repairing effect on the hair. This paper describes the use of silicones as conditioning agents in shampoos, conditioners, and various anhydrous systems. It focuses on the use of silicone gum blends andorganofunctional fluids as basic ingredients in hair care formulations and describes their physicochemical properties, benefits, and functional activity. Recommendations and guidelines for formulating with silicone conditioning agents and examples of prototype formulations for conditioning shampoos, conditioners, and anhydrous systems are also included.

Introduction
In response to consumer demands,cosmetic chemists are working to develop hair care products that will impart repairing and conditioning effects on the hair. Silicones can help meet these objectives. Silicones are a family of polymers whose origins lie in the mineral quartz, or silica, which has the chemical formula SiO2. Through reactions such as hydrolysis and condensation, the basic Si-O-Si-O chain or “backbone” structure ofsilicone is formed. The addition of different functional groups results in a variety of silicones with differing properties. The proper selection of an individual silicone for an application depends upon the properties desired in the final product.

Selecting Silicones for Conditioning Shampoos
Figure 1 summarizes the variety of silicone materials available for use in conditioning shampoos.Cyclomethicone is the Cosmetic, Toiletry, and Fragrance (CTFA) 1

designation for volatile cyclic silicones. These materials offer temporary conditioning and are generally used to formulate products with detangling properties. Dimethicone, another methyl silicone, is available in a wide variety of viscosities and molecular weights. Dimethicones with viscosities less than 5 cSt are considered volatile; themost commonly used forms for personal care applications range from 350 cSt to 12,500 cSt. It is generally true that conditioning effects improve with increasing viscosity, but higher viscosities may be more difficult to formulate. Two silicone “gum blends” were developed to offer a higher degree of conditioning to the hair and to make it feel more silky. These two silicones are known by theirCTFA designations of: • dimethicone (and) dimethiconol • cyclomethicone (and) dimethiconol These products are dispersions of very high molecular weight silicone gums in fluids of very low molecular weight dimethicone or cyclomethicone. The resulting

Silicone: The Basis of a Perfect Formulation for Hair Care

Start
transient conditioning

Cyclomethicone nontransient conditioning Ease of useDimethicone fluids Inproved sensory feel Dimethicone/ dimethiconol gums Ease of use Clarity Formulation 1

Silicone emulsions 1 Solubility 2 Premix 3 Fine TSA emulsion 4 Silicone cationic emulsion/aging

Dimethicone emulsions Improved sensory feel HV dimethiconol emulsions

Dimethicone copolyol Improved conditioning HV dimethicone copolyol

TSA Improved feel TSA with thickener

TSAemulsions

Amodimethicone

Formulation 4 Opacity Body

Formulation 2

Formulation 3

Formulation 5

Figure 1. Silicone selection guide for conditioning shampoos

materials have viscosities in the range of 4,000 cP to 5,000 cP, and they are commonly used in the formulation of 2-in-1 conditioning shampoos. However, their use requires adherence to specific formulating techniques to...