By Shin Hee Lee* and Anthony D. Sabatelli** --
The global hair coloring product market is projected to grow into a 200 billion-dollar industry by 2025. Coty reported in 2017 that more than half of all women color their hair regularly. For example, these figures have reached 62% in the United States, 67% in the United Kingdom, 69% in Germany, and 88% in Russia. An in-depth data analysis reported by Grand View Research, Inc. attributes this rapid growth to a global increase in the aging population, environmental insults such as air pollution, and new trends in the fashion industry. Alongside the other lucrative sectors in the beauty industry that were discussed in our previous articles, "Patent Beauty: IP and the Cosmeceutical Industry" and "Patent Beauty: IP and Hair Care Products", the hair coloring sector also deserves a great amount of attention, especially in view of advancing technologies and the intellectual property covering it.
Hair coloring products are categorized into three types: temporary dyes, semi-permanent dyes, and permanent (oxidative) hair dyes. Temporary dyes generally wash away after 1 or 2 shampooings because they only cover the surface of the hair. Semi-permanent dyes penetrate into the hair shaft and can last up to 10 washings. Permanent hair dyes chemically modify the hair shaft. These dyes use oxidizing amines and phenols in combination with hydrogen peroxide to deliver penetrating dyes into the cortex of the hair. Consumers can therefore choose the type of dye based on their needs, widely ranging from covering gray hair, creating highlights, providing subtle tone-up of the natural color, to performing a complete color transformation. User-friendly coloring packs with step-by-step instructions are accessible for home use, whereas other consumers prefer having professional coloring done in a salon setting.
Hair coloring products have a long history. In ancient times people colored their hair with various plant extracts, but this often resulted in darkening the hair resulting in unpredictable colors. Those seeking to lighten their hair resorted to harsh chemical treatments including caustic compounds. In 1907, Eugene Schueller, a French chemist and founder of L'Oréal, introduced chemical hair dyes that enabled a large variety of colors and desirable results. Coty, Henkel, Kao Corporation, Avon Products, Revlon, Goldwell, Wella, and Combe also joined the market and have become major vendors of hair coloring products. These companies have not only been developing hair dye compounds, but also convenient methods for coloring the hair such as compact kits and specially designed dye applicators.
Despite the effectiveness of chemical colorants, consumers have been concerned about hair damage as well as the potential health risks associated with their use. These concerns have encouraged consumers to seek more natural and organic hair dyes. A United States patent granted to the Natural Medicine Institute of Zhejiang Yangshentang in Hangzhou (US 9,345,654 B2) reports a natural dye product made of plant polyphenols, gardenia blue, cocoa pigment, purple sweet potato pigment, purple cabbage pigment or algae blue pigment. A very intriguing hair dyeing composition was highlighted in the New York Times a few months ago. These compositions utilize graphene-based hair dyes developed by the Huang group of Northwestern University. Graphene is a single atom thick layer of carbon in a molecular state, i.e., a very thin graphite layer. It is a naturally dark material that creates a natural-looking black hair shade, something which has long been a challenge in the hair-dye industry. This graphene hair dye is reported to exhibit durability comparable to permanent hair dyes, and may be more easily applied by spraying, brushing, and then drying.
Natural and organic dyes are safe alternatives to existing synthetic dyes, but render a limited number of hair color options. Researchers have been developing non-toxic synthetic dye molecules that are capable of achieving both safe and large array of hair colors. Clairol, a Coty-owned brand, introduced an "allergy gentle" hair dye molecule called ME+ (2-methoxymethyl-p-phenylenediamine) in 2013. It replaces two existing synthetic dye molecules (phenylenediamine and toluenediamine) that are in 90 percent of the permanent hair coloring products and which are believed responsible for most common hair dye allergies.
Silicone technology and silicone-based polymers have found their way into a number of hair coloring products. Many colorant packages include complementary conditioning and/or treatment hair conditioners comprised of silicone-based materials to minimize damage caused by the chemical dyes. For example, the Procter & Gamble Company patented a process and kit for improved hair conditioning after coloring that utilizes functionalized silicones to condition oxidatively-treated hair (US 7,393.365 B2). Procter & Gamble also disclosed a soluble solid hair coloring article containing, but not limited to, silicone-based polymers (US 8,444,716 B1).
Today, the novelty hair colorant market is arguably one of the largest profit sectors within the hair coloring market. This market is expected to grow at a fast compound annual growth rate of over 20%. Vibrant, blonde, brown, red, paste, metallic, ombre, highlights, balayage (a graduated highlighting effect), color melting, and black are the main categories for these novelty products. Even the names of the hair colors themselves are extending from conventional terminologies to creative ones such as Iced Caramel Latte, Blackberry, Hollywood Opal, Bright Butterbeer, and many more. Phillip Pelusi, a hair care expert, recently stated that "besides mastering the formulation and application techniques, keeping the color molecules intact longer will be the next biggest challenge for stylists and guests alike." Whether it is a temporary dye or a permanent dye, preserving a new hair color while keeping the hair healthy still remains a big challenge for hair coloring developers. Below are some patents for various hair coloring technologies.
 Kaplan, "In Search of the Perfect Hair Dye," posted on the New York Times -- reports on newly discovered graphene-based pigments by Dr. Jianxing Huang of Northwestern University.
* Shin Hee Lee is a Ph.D. Candidate in the Chemistry Department at Yale University. She is currently associated with the Yale Energy Sciences Institute, where she specializes in organic synthesis of novel light-harvesting dye molecules for solar cells. Prior to attending Yale, Shin Hee obtained her B.S. in Chemistry with High Honors at the University of Michigan – Ann Arbor, during which she published patents and papers on developing synthetic methodologies for fluorinated small molecules.
** Dr. Sabatelli is a Partner with Dilworth IP