IP Trends In Hair Care Polymers
Intellectual property trends are revealed by careful study of emerging patent applications. This article reviews the past six months of published U.S patent applications that pertain to polymers in hair care.
Robert Y. Lochhead
The Institute for Formulation Science
The University of Southern Mississippi
Most of us are aware of the hassle that liquid products create as we go through security in airports—stuffing our toiletries into polyolefin bags and hoping that we will remember them as we dash out the other side of security to the departure gate. If only there were suitable solid product forms that we could safely stow in our hand luggage—then we could get through security faster and spend less time trying to remember to pick up all our belongings.
The people at Procter & Gamble are addressing this issue by proposing personal care compositions in the form of solid articles.1 These are porous structures in which the strength in the dry state is conferred by hydrophilic polymers such as poly(vinyl alcohol) or hydroxylpropylmethylcellulose. Because they are porous, they dissolve readily in water and are easy to apply in the washroom or the shower.
There are other advantages to this technology; since the products are devoid of water, shipping costs are reduced and since they are solid form, the amount of packaging can be reduced. The latter is a significant factor considering that most of the used packages end up in landfills. However, the development of such a new product form is no simple matter. The products are made by extrusion, a complicated process for the production of fragile foams of specific shape. The products must be flexible to withstand the forces of shipping and be “dissolvable” by hand dissolution in less than 30 strokes.
The article must have a specific surface area, which is measured by gas adsorption using the Brunauer Emmet and Teller (BET) technique. Teller is the scientist who helped lead the Manhattan Project. Fortunately, P&G scientists overcame these challenges and have managed to produce solid porous forms for a range of purposes from cleansing to shaving preparations.
Hair fixatives such as gels and mousses are often applied to wet hair after shampooing and prior to styling. Such wetting can lead to a loss of the mechanical properties of hair and subsequent loss of style before the fixative has time to set it in place. In order to address such deficiencies, Procter & Gamble investigators have developed a quick-drying approach.2 The quick drying agents are specific aminosilicones.
Hold with Shine
Hair fixatives with improved shine were reported by Rohm & Haas (now Dow Chemical) researchers.3 The high gloss is achieved by including 30-75% of a monomer having a refractive index of 1.49 or higher. These polymers are exemplified by copolymers of styrene, meth-acrylic acid and hydroxyl ethyl methacrylate. The polymers were thoroughly researched. Molecular weight and molecular weight distributions are determined by size exclusion chromatography. The molecular weights are controlled by chain-transfer to ensure that the Brookfield viscosities of test solutions with 12% polymer are below 50 mPa.s. The turbidities of sample solutions were measured by nephelometry. Gloss measurements on films cast from the polymers were measured by ASTM test D 1455 (2000) using a Gardner Byk micro-tri-glossmeter. In applications testing, loop deformation, curl retention and high humidity curl retention were used to evaluate hold. Shampoo removability was determined by panel “feel” tests.
Fixative forms such as gels or mousses can be used with heating devices to style and straighten hair. Such processes are designed for temporary styling. Over the course of a day, the styling benefits conferred by these treatments can lose their effectiveness and they rarely maintain the desired style for a second day. In this respect, an interesting advance has been disclosed for the long-term styling of hair with the option of changing the shape anytime at will,4 which is achieved by placing a polysiloxane/urea block copolymer to the hair and applying heat.
The block copolymer is substantive to the hair and the treatment is durable. Moreover, because the polymer is thermoplastic, the style can be changed at any time by the reapplication of heat sufficient to melt the polymer. The polymers are synthesized by chain extending polyether and polyester polyols (Baycoll from Bayer or Acclaim from Lyondell) or bishydroxyalkylsilicones (TegomerH-Si 2111 from Evonik) and/or and alpha, omega aminosilicone (Wacker Belsil series) with an appropriate di-isocyanate (Desmodurseries from Bayer). A simple composition comprising 2% siloxane/urethane block copolymer dissolved in ethanol (55%) and cyclopentasiloxane (43%) is applied to the hair, which is wound around a curling iron at 200°C to produce a ringlet. The ringlet was easily straightened with a flat iron and then recurled with a curling iron.
Another approach for long-lasting control of frizz involves the polymerization of perfluoroacrylates directly on the hair. The process involves the application of heat to “non-toxic” compositions comprising the fluoromonomer and initiator on the hair.5 Two hurdles can be anticipated for the commercial introduction of this treatment: reluctance of the industry to polymerize monomers on the hair and the potential environmental hurdles related to bio-persistence of perfluorinated compounds.
Consistent with the Clean Air Act and California Air Resources Board (CARB) regulations, polymers continue to be designed for low-VOC compositions. In this context, BASF scientists have synthesized copolymers of (meth)acrylates, (meth) acrylic acids and polymerizable polyether or polyesters to be compatible with 55% VOC hair spray compositions.6
Styling lotions would be preferentially dispensed from water alone rather than from any volatile organic compound. Cationic polyelectrolytes, usually regarded as conditioners, can be used for this purpose. Examples of such polyelectrolytes are polymers and copolymers of poly (4-vinylpyridine), poly (vinylamine), or poly(diallylamine). For example, a lotion which is essentially an aqueous solution of 6% poly(diallyl- amine) gives good hair setting with smooth conditioned feel.7
Improved conditioning terpolymers synthesized from diallyldimethylammonium chloride, diallylamine and telechelic divinylmethicones have been reported by Ciba (now BASF) researchers.8 These polymers are being touted for skin benefits as well as hair conditioning benefits.
Polyquaternium-10 and hydroxypropyl guar trimonium chloride have dominated the conditioning shampoo scene for more than a quarter of a century. Dispersion of hydrophilic polymers in aqueous media is often a tricky process and improper dispersion can result in long mixing times or “fish eyes” in the product. Moreover, if not controlled, these dusty powders can decorate every surface with which they come into contact. In the case of guar derivatives, acidification of the aqueous media assists the dispersion of the polymer powder. In order to alleviate these difficulties, Rhodia has come up with surface-treatment for polysaccharides that allow for easy dispersion.9 Basically, the polysaccharide particles are granulated using the following options as binding and/or dispersing agent and/or wetting agent: water, an inorganic salt, an anionic surfactant, an amphoteric surfactant, a nonionic surfactant, a water-dispersible polymer, a mono- or di-saccharide solution, a polyol and/or a fatty acid. The granulated particles are less dusty. The wetting rate is determined by a simple test in which the polymer is added to the aqueous media in a beaker and stirred with a magnetic stirrer. Brookfield viscosity readings are taken until the viscosity reaches a stable value and the time required to achieve this stable viscosity is taken as the wetting time.
Rhodia has introduced “triquat” copolymers that are synthesized using monomers that contain three quaternary nitrogen groups.10 The polymer has been positioned for inclusion into conditioning shampoos.
Recently, Procter & Gamble researchers have advanced the utility of this type of conditioning shampoo by showing that the inclusion of triquat polymers or cationic starch enhances the deposition of the antidandruff agent zinc pyrithione.11,12 Polymer-surfactant coacervates phase separate by dilution of this type of conditioning shampoo and these coacervates apparently are also able to enhance the deposition of the antidandruff ingredient. The labile zinc in this case was detected in the rinse water by colorimetry with the metallochromic dye xylenol orange.
Coacervates have been used since the 1980s to enhance the deposition of silicones on hair. However, it is well known that most of the silicones don’t end up on the hair but go down the drain during rinsing. Aminosilicones have been tried with the hypothesis that they should be more substantive to hair. However, the aminosilicone emulsions shear easily to produce even finer particle sizes and the small particles deposit poorly on hair. Thus, the chemical modification of silicones frustrates the physical deposition on hair. A recent patent application discloses a method to maintain the aminosilicone particles in the size range from approximately 3-150 microns, which is optimal for deposition.13 Stabilization of the particles is achieved by including polymeric protecting agents. These protecting agents are polymeric surfactants derived from either natural or synthetic polymers. Pickering emulsions are also disclosed, in which the droplets are protected by smaller particles adsorbed at the silicone/water interface. The claimed protecting agent is decyl glucoside and bis-PEG/PPG-14/14 dimethicone.
These particles also shown to possess antibacterial properties as the result of challenge tests using Staph. Aureus and E. Coli.
Trends that have been noted in this article are:
• The development of porous solid forms of personal care compositions to remove water thereby reduce shipping costs and packaging disposal costs.
• Quick-dry compositions that allow better hair styling.
• Hair fixatives offering improved shine from polymers that contain significant amounts of monomers having refractive indices greater than 1.49.
• Long-lasting style from siloxane/urea block copolymers and long-lasting anti-frizz from the polymerization of perfluoroacrylates on the hair.
• The continuation of the development of low-VOC fixatives.
• Improved polymers for deposition from shampoos, which include better-dispersing cationic guars, polymers that include triquat monomers, cationic starches and polymeric stabilizers for aminosilicone droplets.
• Surface treated nanoparticles for conditioning.
1. Glenn, J.R., Robert Wayne; Morrissey, Christopher Todd; Schechtman, Lee Arnold; Bolden, Renee Danielle; Kaufman, Kathleen Mary; Bartz, Lisa Jo; Dufresne, Thomas Edward; Trokhan, Darren Paul; Heinrich, James Merle; Personal care compositions, especially those personal care compositions in the form of an article that is a porous, dissolvable solid structure; United States Patent Application 20090232873; September 17, 2009
2. Maillefer, Sarah; Pluss, Jolanda; Flohr, Andreas; Method and Composition for Reducing the Drying Time of Hair; United States Patent Application 20090226381, September 10, 2009
3. Collin, Jennifer Reichl;Hallden-Abberton, Michael Paul; Falcone, Beth Ann; Wang, Miao; Zeng, Fanwen; Hair styling composition, United States Patent Application20090 252689, October 8, 2009.
4. Vic, Gabin; Brun ,Gaelle; Gourlaouen, Luc; Process for treating hair fibers using polysiloxane /urea, United States Patent Application20090155198, June 18, 2009.
5. Anderson, Daniel Griffith; Nashat, Amir; DeRosa, Mitchell John; Puerta, David Thomas; McLaughlin, Ronald P.; Akcasu, Bryan Scott; Williams, Susan Alice; Ramirez, Richard Matthew; Hair Care compositions and methods of treating hair using same. United States Patent Application 20090226382, September 10, 2009.
6. Winter, Gabi; Pierobon, Marianna; Laubender; Matthias; Kim,Son Nguyen; Setting Polymers based on polyester acrylates, United States Patent Application 20090162295, July 25, 2009.
7. Mougin, Nathalie; Jegou, Gwenaelle; Neutralised cationic polymer, composition containing said polymer and a cosmetic treatment method, United States Patent Application20090202465, August 13, 2009.
8. Jennings, John; Zhou, Xian-Zhi; Preparation of cationic terpolymers and personal care compositions comprising said terpolymers, United States Patent Application 20090175804,July 9, 2009
9. Monin, Vincent; Chiron, Stephanie; Kiefer, Jean-Claude; Polysaccharide-based products with improved ease of use, process to make the same, and applications of the same; United States Patent Application 20090214608; August 27, 2009
10. Liu, Leo Zhaoqing; Monomer Compounds comprising several cationic groups, process for making the same, and polymers comprising units deriving therefrom, United States Patent 7,030,275; April 18, 2006.
11. Peffly, Marjorie Mossman; Hughes, Kendrick Jon; Personal care compositions containing cationic synthetic copolymer and a detersive surfactant; United States Patent Application 20090176674; July 9, 2009
12. Peffly, Marjorie Mossman; Yee, Jacqueline Ellen; Renock, Sean Michael; Hughes, Kendrick Jon; Personal Care Compositions Containing Cationically Modified Starch and an Anionic Surfactant System; United States Patent Application 20090176675; July 9, 2009
13. Hilvert, Jennifer Elaine; Hughes, Kendrick Jon; Johnson, Eric Scott; Deckner, George Endel; Wells, Robert Lee;Conditioning Shampoo Containing Stabilized Silicone Particles; United States Patent Application 20090176676;July 9, 2009.
14. Jennings, John; Haglin, Dietmar; Mao, Jianwen; Muhlebach, Andreas; Preparation of cationic nanoparticles and personal care compositions comprising said nanoparticles;United States Patent Application 20090214447; August 27, 2009