What do the latest patent applications reveal about what’s happening in new technology for hair products?
Robert Y. Lochhead and Ashley Cox
The Institute for Formulation Science and The School of Polymers & High Performance Materials
The University of Southern Mississippi
One of the first uses of synthetic polymers in hair care was for hair fixatives in hairsprays. It has long been understood that hairstyling products should be designed to hold the hair in a desired style until the next time the hair is washed, at which time it should be removed completely as the hair is cleansed.
However, many fixative polymers are sensitive to moisture from humidity, rain or sweat and this causes the hair to lose its style prematurely. It has been disclosed that good fixation with less susceptibility to moisture can be achieved from compositions containing a fixative polymer having an acidic vinyl monomer, a hydrophobic nonionic vinyl monomer, a first and second associative monomer, a semihydrophobic monomer; and a second copolymer comprising a C3-C8 ethylenically unsaturated monocarboxylic acid monomer, a nonionic vinyl monomer and a hydroxy substituted nonionic vinyl monomer.1
A preferred second polymer is acrylates/hydroxyesters acrylates copolymer (Acudyne 180 from Rohm and Haas). A preferred first polymer is polyacrylate-14 (Fixate Plus from Lubrizol Advanced Materials). Polyacrylate-14 is a polymer that contains hydrophilic, semihydrophobic and hydrophobic monomers. It exhibits the dual advantages of being a hair gel thickener and a film-forming hair fixative.2 Another rheology modifier/hair styling resin has recently been claimed.3 The claimed polymer is a cross-linked linear poly (vinyl amide/ polymerizable carboxylic acid) copolymer, in which the vinyl amide is selected from vinyl pyrrolidone, vinyl caprolactam, N-vinylformamide or N-vinyl acetamide. The polymerizable carboxylic acid can be (meth)acrylic acid.
Hair fixatives containing a single polymer can be formulated to provide hair with excellent hold or style. Frequently, however, these products leave the hair feeling stiff and unnatural. Improved products, with low tackiness and good shampoo removability, can be achieved by combining an amphoteric polymer with a nonionic polymer but these products are easily plasticized by humidity leading to loss of the desired style. The elasticity of the polymer film and the durability of “hold” can be improved by combining an amphoteric polymer, an anionic fixative polymer and a nonionic fixative polymer in a hair fixative composition.4
A preferred amphoteric polymer is octylacrylamide/acrylic acid/butyla-minoethyl methacrylate/methylmetha-crylate /hydroxypropylmethacrylate/co-polymer (Amphomer from National Starch); a preferred anionic polymer is 2-ethyl acrylate/ N-t-butylacrylamide (Ultra Hold 8), and a preferred nonionic polymer is PVP.
The search for the desired paradoxical properties of humidity resistance, excellent hold, good gloss and feel, and easy shampoo removability imparted by a single fixative polymer, may have reached a successful conclusion with the introduction of polyacrylate-2 crosspolymer (Fixate Superhold Polymer from Lubrizol Advanced Materials).5 This is a new branched acrylate copolymer of C1-C4 alkyl (meth)acrylate, (meth)acrylic acid and an amphipathic moiety that contains silicone side chains and associative hydrophobic chains.6 Soft, hydrophobic domains are randomly combined with hard, hydrophilic domains to form the backbone of this polymer, and this results in the simultaneous achievement of the paradoxical properties of stiffness and humidity resistance combined with the sensory attributes of shine enhancement and ease of distribution through hair.
| Several new polymers promise to enhance styling.
Permanent waving is often achieved by reducing the disulfide bonds of the hair, tensioning the hair to a desired configuration, then oxidizing the SH groups back to S-S to hold the hair in its new configuration. Tensioning of the reduced hair leads to mechanical and chemical damage which is exacerbated by the oxidation step. Moreover, conventional permanent waving achieves volumizing by making the hair curly, but consumers want volume without the curl. This has been addressed by conducting the reduction step in the presence of a fixing polymer that is precipitated by the reducing salt.8 When the polymer precipitates, it most likely holds the hair in shape during the reduction and fixing steps without the need for mechanical tensioning. Moreover the set lasts twice as long as the conventional treatment. An exemplary polymer for this purpose is crotonic acid/vinyl acetate/vinyl t-butyl benzoate terpolymer (Mexomer PW from Chimex).
Thickeners Continue to Improve
Hydrophobically-modified, alkali-swell- able thickening latex copolymers are useful and highly efficient thickeners for aqueous formulations. However, these latex copolymers start to build viscosity only when the pH is raised above 5 or 6. Acrylates copolymer (Carbopol Aqua SF-1 Copolymer from Lubrizol Advanced Materials), however, shows interesting synergy in surfactant systems. Surfactant compositions that contain a sufficient concentration of this acrylate copolymer show an expected increase in viscosity as the pH is increased above 5 or 6. However, when acid is added to the neutralized system, the surfactant compositions continue to increase in viscosity as the pH is lowered.9 This formulation technique, called “back-acid” thickening, renders this thickener useful even below pH 5. 10
Copolymers of 2-acrylamido-2-methyl -propanesulphonic acid (also known as N-acryloyl taurate) and acrylic acid can be differentiated from conventional acrylate by their ability to thicken low pH compositions.11 If the molecular weight is higher than 6,000,000 and the 2-acrylamido-2-methylpropanesulphonate content is greater than 20%, then the polymer also confers yield stress and shear thinning characteristics on the composition. Unlike other polyelectrolyte thickeners, these thickeners also resist dramatic viscosity loss in the presence of the UVA sunscreen 1,4-benzene[di(3-methylidene-10-camphorsulfonic)]acid. Acryloyl taurate/ vinyl pyrrolidone copolymer is an efficient thickener and stabilizer for emulsion compositions containing alpha- and beta-hydroxyacids.12 It is known that comb copolymers made by polymerizing N-acryloyl taurate with commercially available macro- monomers exhibit good thickening and emulsifying properties and clarity.13,14 Copolymers of 2-acrylamido-2-methylpropanesulphonic acid and acrylic acid demonstrate a sticky feel as they dry out, but cross-linked copolymers of 2-acrylamido-2-methylpropanesulphonic acid and hydroxyethylacrylamide give the benefits of thickening at low pH values, without the negative attribute of sticky feel.15
The production of stable, high solids, inverse latexes involves some significant technical challenges, but it has recently been reported that inverse latexes of cationic and anionic thickening polymers have been successfully prepared at greater than 50% concentrations.16 These products offer the prospect of easily processable thickeners with lower concentrations of carrier oil. BASF scientists have disclosed a spray polymerization method to produce polymeric thickeners.17 It will be interesting to learn more about the properties of these spray polymerized materials.
Advances in Conditioning
Conventional conditioning of damaged hair is commonly achieved by treatment with aqueous formulations that contain fatty alcohols, cationic surfactants and, optionally, silicones. Cationic conditioning polymers can be added to these formulations to enhance conditioning attributes, but the formulator must be careful to avoid increasing viscosity to the extent that facile spreading of the formulation on hair is compromised. However, compositions that readily spread on hair to confer disentangling and feel benefits, can be formulated using a polyol of higher molecular weight than ethylene glycol, and/or an aminosilicone with a cationic polyvinyllactam.18,19
| Better polymers mean better hair styling options.
Multiple Emulsion Benefits
Hair styling creams are emulsions that confer hold and luster to medium length hair. They are usually worked into the hair by hand after they have been rubbed between the palms to melt waxy components. Once on the hair, solvent may evaporate and the composition hardens to fix the hair style and to impart improved shine. More advanced products form fibers when the hands are pulled apart and they can be applied to the hair as a spider-web-like net. Particular skill in formulation is required to make fiber-forming creams that are not sticky or greasy during application. It has now been found that high performance fiber-forming emulsion hair styling creams can be formulated by including a crosslinked silicone polymer (dimethicone crosspolymer), a polyethoxylated compound (PEG-10 or 12, or PEG-x dimethicone), an emulsifier and a fatty phase in the composition.21
Multiple emulsions have tantalized formulators for a considerable time because of the prospect of simultaneous delivery of mutually incompatible ingredients to confer new and useful effects. However, the commercial exploitation of multiple emulsions has been limited by the complexities and difficulties of manufacture and their sensitivity to other formulation ingredients as well as their lack of stability during storage. It is gratifying, therefore, to learn of a water-in-oil-in-water (W/O/W) emulsion that can be made by a single-step process and which exhibits improved storage stability.22 The system comprises an organosiloxane elastomer crosslinked with polyether chains (KSG-210, KSG-310, KSG-320, KSG-340, KSG-710, KSG-810, KSG-820,KSG-830, or KSG-840 from Shin-Etsu Chemical Co.), Sepigel 305 from Seppic and Simulgel RMS being preferred. The W/O/W emulsion can be applied as a conditioner that provides good gloss to the hair.
Polyampholytes have been commercially available as conditioning polymers for a considerable time. A prominent example is polyquaternium-39 (Merquat 3330 from Nalco). An improved version of this type of terpolymer of diallyldimethylammonium chloride, acrylamide, and acrylic acid has been disclosed.23 This polymer is prepared by a monomer feed method for better control of molecular weight and composition.
New Uses for Cassia
Guar hydroxypropyltrimonium chloride is a cationic polygalactomannan that has been used for three decades as a hair conditioning polymer. Another cationic polygalactomannan, cationic cassia gum, has recently been patented.24 Polygalactomannans consist of a polymannan backbone with galactose side groups. In guar gum, there is a pendant galactose side group for every two mannan backbone units. These galactose groups sterically hinder the substitutable C-6 hydroxyl unit and this limits the extent of possible cationic substitution on guar gum. In cassia, however, there is less steric hindrance of the C-6 hydroxyl group and, consequently, higher degrees of cationic substitution are possible with cassia (60% for cassia relative to 30% for guar). Cationic cassia can be used as a conditioning polymer in shampoos and conditioners to impart cleansing, wet- detangling, dry-detangling and manageability and it is also relatively nonirritating making it suitable for use on children. These cationic polymers operate by depositing a polymer-surfactant complex coacervate that separates as a distinct phase during the rinsing step of the shampoo process. Maximum coacervate deposition occurs at precise ratios of cationic polymer:anionic surfactant but the optimum ratio for coacervation might not coincide with the best ratios for cleaning and foaming. Synthetic copolymers of acrylamide and a triquat monomer are postulated to provide improved deposition on hair and improved conditioning performance with respect to wet combing.25
For more than two decades, most conditioning shampoos have contained dispersed silicone droplets destined to deposit on the hair surface during shampooing to confer conditioning benefits. With multiple uses, however, the silicone can build up on the hair and weigh it down, leading to unattractive “droop” and lack of style. Moreover, the silicone droplets and commonly used suspension stabilizers scatter light and cause the shampoo compositions to lose clarity, or even to be opaque. Now, however, transparent conditioning shampoos can be formulated by including pregelatinized starch with the usual polyquaternium-10 type of polymers in the shampoo composition.26 The pre-gelatinized starch is preferably hydroxypropyl distarch phosphate (Structure XL from National Starch). These do not weigh down the hair with oily deposits and, they are taught to provide excellent performance on frequent and regular use. Formulations based upon cationic polymers and oils have been used to disentangle, and provide softness and flexibility to hair damaged by chemical treatments such as perming, bleaching or dyeing. However, there is a tendency for such formulations to build up on the hair leaving it lank. This drawback can be overcome by deep conditioning. Effective conditioning formulas may contain vegetable oils, (such as olive oil or avocado oil), a cationic polysaccharide and acrylates copolymer (Carbopol Aqua SF-1 Copolymer from Lubrizol Advanced Materials).27 Acrylates copolymer is also useful for thickening conditioning shampoos.28
Another way to minimize buildup is to treat the hair with water-in-water emulsions that can be prepared by including cationic polymers with soluble salts in surfactant compositions.29 These water-in-water emulsions provide conditioning benefits with good spread of the conditioning phase on the hair and less chance of buildup.
The use of polymeric antimicrobial agents is growing. In one application, antimicrobial agents, such as silver, were combined with a crosslinked hydrogel, to create a hydrophilic polymer antimicrobial system that has potential application in the personal care industry, including cosmetic, skin treatment, diapers and bandages.30
However, there may be no need to include antimicrobial silver particles if the polymers possess antimicrobial properties. For example, Daly and his research team found that chitosan is readily converted to 3-trimethylammonium-2-hydroxypropyl-N-chitosan (CHI-Q188). N-Carboxymethyl chitosan can be converted to an N',N'-dimethylammonium propyl carbamoyl-derivative and further modified by quaternization to produce a series of chitosan aminoamide quats. The antimicrobial activity of CHI-Q188 against Escherichia coli, Staphylococ-cus aureus and Pseudomonas aeruginosa was determined using the minimum inhibitory concentration test. The derivative exhibited biocidal activity at least an order of magnitude higher than previously reported chitosan antimicrobial agents.31
Polyethylenenimine polymers have been utilized as polymeric antimicrobial agents. For example, an antimicrobial polymer derived from polyethylenenimine was effective against pathogenic gram positive and gram negative bacteria, yeasts and molds, and skin flora bacteria.32 Copolymers and derivatives of polyethylenimine with broad-spectrum antimicrobial properties are active against microbes on contact. The large molecular size of these compounds enables them to resist removal from substrates and also prevents their ingress into the lower layers of skin of humans and animals. A range of uses for these polymeric antimicrobial agents is anticipated—from shampoos to marine antifouling coatings.33
Polymeric antimicrobials can also be effective against yeasts. Mahmoud and coworkers tested modified poly(methylmethacrylate-co-vinylbenzoylchloride) and modified linear poly(chloroethyl- vinylether-co-vinylbenzoylchloride) against Candida albicans and Candida tropicalis. The poly(methylmethacrylate-co-vinylbenzoylchloride) proved more active against both C. albicans and C. tropicalis because of its increased cytotoxicity on bacteria and its interference with the cell walls. Poly(chloroethylvinylether-co-vinylbenzoylchloride) also proved effective through its detrimental effects on the permeability of yeast cells and respiration. Both poly(methylmethacrylate-co-vinylbenzoylchloride) and poly- (chloroethylvinylether-co-vinylbenzoylchloride) provide promising application potential in the biomedical field.
Finally, old and new antidandruff technologies have been united by combining cationic polymers, such as hydrophobically modified quaternary ammonium cellulose ether, with antimicrobial compounds, such as sodium pyrithione, or zinc pyrithione.34 This cationic antimicrobial polymer system displayed effective antimicrobial properties at lower antimicrobial agent concentrations than conventional systems.
The trends that we have discerned for polymers in hair care can be summed up as:
• A continuing trend to extend the range of thickeners to hitherto inaccessible pH values and salt concentrations while enhancing the feel attributes of the thickener;
• A drive toward single polymers with dual functionality; such as thickening and film-forming, or extreme fixing that resists humidity while conferring good feel properties;
• Attempts to produce fixative products that impart excellent and reshapable style;
• The endeavor to achieve good conditioning without buildup of residue on the hair and
• An exploration of macromolecular antimicrobials and preservatives. l
1. Water, A.; Birkel, S.; Franzke , M.; Schmitt, K.; Moisture resistant hair styling composition containing two polymers, U.S. Patent 20070197704, Aug. 23, 2007; assigned to the Procter & Gamble Company.
2. Fixate Plus Polymer, TDS-331, Oct. 23, 2007, http://www.personalcare.noveon.com/Technical DataSheets/TDS-331_Fixate_PLUS.pdf
3. Drezwinski, M.; Albanese, J.; Yap, E.; Shih, J.S.; Rheology modifier/ hairstyling resin U.S. Patent Application 2007020264, Aug. 30, 2007; International Specialty Products.
4. Gaenger, K.; Florig ,E.; Hair treatment composition containing a combination of three different film-forming hair-fixing polymers, U.S. Patent 7,279,153; Oct. 9, 2007; assigned to Wella AG.
5. Fixate Superhold Polymer, Technical Data Sheet TDS 5565 2007093K, The Lubrizol Corporation
6. Krysik, D.; Rafferty, D.W.; Tamareselvy, K.; Zellia, J.; Liu, X.; Shlepr, J,; “Advancements in styling technology – Fixate superhold polymer provides stiff hold and superior humidity resistance to styling products, Cosmetics and Toiletries Manufacture Worldwide, 2007, p 11.
7. Gawtrey, J; Gel with a high concentrating branched sulfonic polyester and method for preparing same, U.S. Patent Application 20070218091, Sept. 20, 2007; assigned to L’Oréal.
8. Campain, C.; Devin-Baudoin, P.; Process for permanently reshaping the hair; U.S. Patent Application 2007019008, Aug. 16, 2007.
9. Schmucker-Castner, J.; Ambuter, H.; Snyder, M.; Weaver, A.A.; Kotian, S.; Stable aqueous surfactant composition, U.S. Patent 7,217, 752; May 15, 2007; assigned to Noveon.
10 Carbopol Aqua SF-1 Polymer Technical Data Sheet TDS -294, Edition: July 2007, http://www.personalcare.noveon.com/TechnicalDataSheets/TDS-294_ Carbo pol_ Aqua_ SF-1.pdf
11. Ito, K.; Mori, Y.; U.S. Patent Application 20060046949; Mar. 2, 2006
12. Suares, A. J.; Zhang, J. H., U.S. Patent 6,986,895, Jan. 17, 2006, assigned to Unilever Home & Personal Care USA.
13. Morschhauser, R.; Löffler, M.; Maier, I.; U.S. Patent 6,964,995; Nov. 15, 2005; assigned to Clariant .
14. Morschhäuser, R.; Glauder, J.; Löffler, M.; Kayser, C. ; Tardi, A.; U.S. Patent 6,891,011, May 10, 2005, assigned to Clariant
15. Sogabe, A.; Kaneda, I; U.S. Patent Application 20070231354, Oct. 4, 2007.
16. Braun, O.; Novel concentrated inverse latex, production method and use thereof in industry, U.S. Patent Application 20070219315, Sept. 20, 2007.
17. Losh, D.;Weidl, C.H.; Seidl, V.; Method for producing polymers by dispersion polymerization, U.S. Patent Application 20070244280; assigned to BASF.
18. Bebot, C; Cosmetic composition comprising at least one cationic poly (vinyllactam), at least one fatty alcohol, and at least polyol, cosmetic process for treating keratin fibers and use of the composition, U.S. Patent Application 20070190015, Aug. 16, 2007.
19. Pasquet, D.; Bebot; C.; Cosmetic composition comprising at least one cationic poly (vinyllactam), at least one fatty alcohol, and at least one amino silicone, cosmetic process and use of the composition., U.S. Patent Application 20070190016, Aug. 16, 2007
20. Chrisstoffels, L.; Becker, S.; Volkel, L.; Polymers comprising diallylamines, U.S. Patent Application 20070191548, Aug. 16, 2007,
21. Walter, A.; Hannich, M.; Schmich, B.; Loifenfeld, M.; Hair styling cream, U.S. Patent Application 20070202068, Aug. 30, 2007; The Procter & Gamble Company.
22. Kelly-Hernandez, M.; Muller, T.; Springob, C.; Monks, M.; Weber, D.; Stable oil-in-water and water /oil/ water multiple emulsions for hair treating compositions comprising them, U.S. Patent Application 20070202067, Aug. 30, 2007; The Procter & Gamble Company.
23. Sabelko, J.J. ; Cramm, J.R.; Damyanti, J.; Low molecular weight ampholytic polymers for personal care applications, U.S. Patent Application 20070207106, Sept. 6, 2007; Nalco Company.
24. Utz, F.; Lepilleur C.A.; Tamareselvy, K.; Chiarelli, J.A.; Schmucker-Castner, J.F.; Myers, M.P.; Hasman, D.F.; Vondruska, B.J.; Wilber, W.R.; Luo, H.; Marchant, N.S.; Shuster, F.; Cationic Cassia derivatives and applications therefor, U.S. Patent 7,262,157; Aug. 28,2007; assigned to Lubrizol Advanced Materials.
25. Peffly, M.M.; Brown, M.A.; Staudigel, J. A.; Personal care compositions containing cationic synthetic copolymer and a detersive surfactant, U.S. Patent Application 20070207109, Sept. 6, 2007; The Procter & Gamble Company.
26. Albrecht, H.; Heitmann, B.; Ruppert, S.; Hair shampoo containing pregelatinized, cross-linked starch derivatives, U.S. Patent 7,279,449, Oct. 9, 2007; assigned to Beiersdorf A.G.
27. Maubru, M.; Cosmetic compositions containing a Methacrylic and copolymer and am oil, and uses thereof, U.S. Patent 7,258,852: Aug. 21, 2007; assigned to L’Oréal.
28. Demitz, M.; Doerschen, A.; Kohut, M.; Ruppert,S.; Albrecht, H.; Kuether, J.; Heitmann, B.; Care system constituted of PVP and Acrylate Polymers, U.S. Patent Application 20070212320, Sept. 13, 2007; assigned to Biersdorf.
29. Simonet, F.; Nicolas-Morgantini, L.; Cosmetic composition of water-in-water emulsion type based on surfactants and cationic polymers; U.S. Patent 20070237733, Oct. 11, 2007.
30. Chandra, N.S. ; McNally, W.F.; Furey, J.M.; Robb, G.J.; Harriton, M.L.; Hydrogel having antimicrobial properties, U.S. Patent Application 20060062854, Mar. 23, 2006; Noble Fiber Technologies.
31. http://chemistry.lsu.edu/chem/facultypages/ Faculty.php?chemID = 59
33. X. Huang, T. Deisenroth, A. Preuss, S. Marquis- Bienewald, C. Hendricks-Guy, J. Jennings, “Polymeric anti-microbial agents”, U.S. Patent Application 20070231291, Oct. 4, 2007; Ciba Specialty Chemicals Corporation.