Kao advances foam control technology for foam hair color

The Beauty Research Center of Kao Corporation (President and CEO: Motoki Ozaki) has been studying hair coloring technology for easy application and high dyeing performance. Recently the center has successfully upgraded its original foam-structure controlling technology for foam-type hair color (hair dyeing agent) using a squeeze foamer*. By utilizing a specific surfactant and gels, foaming performance and foam stability (foam with the state of being durable and unbreakable) have been greatly improved, which allows for more spreadable foam with less dripping, leading to easier usability.

Kao developed the first-ever foam-type hair coloring technology using a squeeze foamer. Since summer 2007, Prettia and Blauné foam hair color brands which incorporate the innovative coloring technology have been marketed and gained strong consumer support in Japan. At present, Kao is accelerating its global development of related products that utilize the upgraded technology.

The foam hair color produces rich foam just by squeezing mixed liquid of colorant and developer from a foamer. The smooth, voluminous foam discharged by the foamer is easily applied by the hands throughout all areas of the hair. Then, when gently rubbed by the fingertips, the foam completely penetrates the hair. As the foam is durable enough to remain on the hair, users can color the hair evenly all the way to the roots and back of the head, which are difficult areas to color. Moreover, even when left on for 20 to 30 minutes after application, the unbreakable foam is resistant to dripping, a benefit to users who can color without worries about staining skin and surroundings.

Making use of the study results, Kao is accelerating its global product development with wider coloring variations, which is applicable to diverse hair textures and hair styles the world over. Foam-type hair color products have been launched in three Asian markets (Hong Kong, Singapore and Malaysia), and will be released in Thailand in spring 2011. In Europe, the products were marketed in autumn 2010.

The research result of the advanced foam control technology was reported at the meeting of the International Federation of Societies of Cosmetic Chemists (IFSCC) held in Buenos Aires, Argentina, from September 20 to 23, 2010.

Research Background

Hair color (hair dyeing agent) is widely used around the world for coloring grey hair and for fashionable coloring. The 2-agent type of hair color is the mainstream: colorant is formulated with oxidative dyestuff and solvent, and developer contains hydrogen peroxide for simultaneous function of bleaching and dyeing. The coloring process includes mixing colorant and developer just before application, applying to hair, leaving it on for 20 to 30 minutes to penetrate and settle colorant into hair fibers, and rinsing it away.

Until 2007, when foam hair color products with Kao's innovative technology were launched, liquid or cream types of hair color were very popular. These types are designed with high viscosity to prevent dripping during coloring. To spread the agent all the way to the hair roots, a brush or comb was used to separate hair into small clusters and apply a small portion of the coloring agent, a laborious and time-consuming process. Moreover, it ends up in an uneven finish at the hair roots and back of the head, areas difficult for application. Results of a survey of women who color their hair at home showed that 39 percent of them complain that they "cannot color the hair in the back of the head or the inside layers;" 27 percent of them responded that there was an "uneven finish," and 19 percent noted that it was "troublesome to separate hair bundles for coloring." (Kao survey, November 2007; 107 women in metropolitan areas)

To solve the dissatisfaction about coloring, Kao studied various types of coloring agents as well as the tools in use. Ultimately, Kao discovered that the best way for the agent to penetrate every section of the hair is to directly apply foam onto hair with hands and rub gently with the fingertips by taking advantage of foam volume, softness, and its spreadability.

However, the study faced two requirements: first, how to attain rich foam with volume when foaming by mixing liquid agent and air using a squeeze foamer; second, how to prevent foam loss and dripping during application onto hair and during the following 20 to 30 minutes process time while the foam is left on the hair.

Hair color performs through the mixing of two agents: colorant contains ingredients consisting mainly of dyestuff and solvent with properties against foaming and foam staying power; developer contains ingredients including hydro peroxide for the oxidation of dyestuffs. Thus, Kao has continued the study focusing on developing an optimal foaming agent and improving foam stability technology that fit the 2-agent type agent mechanism.

Research Results

To enhance foaming performance, Kao has chosen a specific anion surfactant AGS (Sodium Acylglutamate) as a foaming agent that is resistant to antifoaming properties of salt and solvent, and formulated it into colorant. This resulted in finer, richer foaming when dispensed from a squeeze foamer.

To improve foam stability (foam with the state of being durable, unbreakable), gels compounded with substances such as STAC (Stearyltrimethylammonium chloride) and Cetanol (Cetostearyl alcohol), which are resistant to oxidation of hydrogen peroxide, are stably dispersed in developer with low density. Such low-density gels have been found useful in the design of a low viscosity liquid that can be used in the squeeze foamer to generate foam. Gels also disperse in foam film after formation of the foam, which increases viscosity in the film by adding structural viscosity as gels. With this mechanism, drainage (liquid fluidity) can be controlled. Moreover, by adjusting gel types and viscosity, foam structure with higher stability can be designed, which results in foam remaining even when left on after wide application, while maintaining the foam's spreadable property.

With these advanced technologies, foam can more easily be spread with less dripping, which facilitates easier application.

About Kao

Kao creates high-value-added products to help consumers around the world enrich their everyday lives. Over 20 leading brands such as Asience, Attack, Bioré, Goldwell, Jergens, John Frieda, Kanebo, Laurier, Merries and Molton Brown are part of the lives of people in Asia, Oceania, North America and Europe and help generate about 1,200 billion yen (about $US13 billion) in annual sales. Kao employs about 35,000 people worldwide and has a 120 year history of innovation. Please visit Kao group web site for updated information.

* Squeeze foamer

A container that, when lightly squeezed, mixes liquid and air in a bottle and generates foam as it dispenses.