After decades of developing hair styling polymers, there is still room for improvement. Many generations of polymers1, 2 have been introduced since the first synthetic styling polymer polyvinylpyrrolidone (PVP) in the 1950s.3 Today’s styling formulations are further optimized with polymer combinations. This is especially true for styling gel and wax formulations, with combinations of styling polymers and polymeric thickeners to achieve the right balance of rheology profile, setting performance and humidity resistance without sacrificing sensory properties, e.g. peaking, gel structure and clarity. A lot of those formulations still contain PVP-based polymers, acrylic-based polymers and carbomer-based thickeners.
Luviset One (INCI: Acrylates/Methacrylamide Copolymer) offers hair care formulators the opportunity to reduce the complexity of styling gel and wax formulations with the use of only one polymer. In addition, Luviset One has the potential to be used in combination with non-ionic, cationic and anionic polymers to give the formulator the necessary flexibility to develop variants with different levels of styling performance and hold properties.
Luviset One is delivered as a water-based polymer dispersion with active polymer content of 30% at pH 5.5. For preparation of clear formulations, pH values of 6.5 and higher are recommended; maximum viscosity is achieved at pH 7 (Figure 1). The polymer is tailor-made to achieve maximum styling performance at a solids content of 4.0 %, (Figure 2), where the viscosity is in the target range of 40-50 mPas (Figure 3).
Hair Styling Gels and Waxes
The styling performance of Luviset One in gel formulations was compared to marketed PVP-based polymer technologies via hair styling formulations containing perfume, solubilizer and preservative (see Simple Strong Styling Gel and Extreme Hold Styling Gel, Figure 4). The comparison was done with a 4% active total polymer level (styling polymer and thickener). In the case of Luviset One, an additional thickener is not required to achieve a target viscosity range of 40-50 Pas.
The maximum bending force of the hair/polymer composite is higher in formulations with the Luviset One than those of conventional vinylpyrrolidone based polymers (see Figure 4). Furthermore, formulations with Luviset One delivered significantly lower flaking results compared to formulations with PVP K 90 or VP/methacrylamide/vinylimidazole copolymer and comparable results to VP/VA copolymer.
Luviset One can be combined with nonionic, cationic and other anionic styling polymers to increase the setting performance without sacrificing gel sensory properties, rheology, and clarity. Figure 5 captures the performance results of the different polymer combinations (4.5-5.0% active polymer) versus Luviset One (4.0% active polymer) and market benchmarks. Combining Luviset One with other polymers provided not only better stiffness properties, but lower flaking results as well.
Luviset One at 4.0 % polymer content can be used to emulsify a range of oils and waxes without the additional conventional emulsifiers to generate new textures and effects. This benefit is explained by the associative interactions due to the hydrophobic monomer moiety in the polymer. A home use test of a styling wax ( see Styling Wax) was performed to assess its application properties.Good hold to the hair on application was found by 73% of users, while 70% found it to be easily rinsed off the hands. Easy rinse off the hair was reported by 83% of responders and 65% found it left no residue on the hair. Restyling was found to be easy by 65% of responders.
Mechanical Properties of Polymer Films
Water uptake from pure not neutralized polymers (Figure 6) and final styling gel formulations with perfume and emulsifier at pH 7 (Figure 7) have been measured as a function of the relative humidity. The water uptake of Luviset One as pure polymer un-neutralized is very low (Figure 6). In final styling gels (Figure 7) at pH 7, Luviset One and its combination with other polymers has higher water-uptake values compared to the un-neutralized polymer (Figure 6,) but water-uptake is still significantly lower than that of carbomer/PVP K90 gels (Figure 7).
Polymer films of final styling gels with Luviset One are extremely stretchable, with elongations of more than 400% (Figure 8). The polymer film from the combination of Luviset One and acrylates copolymer is even more elastic, and the film does not break at maximum stress.
There is a big difference between the mechanical properties of dried styling gels based on Luviset One and classical combinations of vinylpyrrolidone-based polymers and carbomer (Figure 9). Combinations of vinylpyrrolidone-based polymers and carbomer give much more brittle films and exhibit higher maximum tensile stress, but have very low elongation at maximum tensile strength.
The extremely stretchable film properties (Figure 8 and Figure 9) of Luviset One could correlate with its low flaking properties (Figure 5). A prerequisite for low flaking is good adhesion of the polymer on the hair fibers. Good adhesion is only possible if the polymer has a certain elasticity, avoiding breakage upon movement of the hair.
Luviset One provides styling properties and thickening performance for clear styling gel formulations, styling creams and styling waxes without an additional thickener and emulsifier. This polymer has been shown to be compatible with nonionic, anionic and cationic high performance styling polymers to give extreme styling performance and humidity resistance with reduced flaking on hair.
Polymer film specimens formed by the dried gels with the new polymer were found to be flexible and pliable and did not snap or break upon bending and twisting by means of a tensile testing device. Based on these results, it is postulated that these film properties are important for high bending stiffness and low flaking after combing.
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2. R Rigoletto, A Mahadeshwar, L Foltis and D Streuli, Advances in Hair Styling, Cosmet & Toil 372-380 (2013)
3. DRP 737,663, BASF-method for the manufacturing of polymeric N-vinyl compounds, W Reppe, C Schuster and A Hartmann (January 17, 1939)
4. P Hoessel, S Riemann, R Knebl, J. Schroeder, G Schuh and C Castillo, Assessment of styling performance in hair gels and hair sprays by means of a new two-point stiffness test, J Cosmet Sci 61, 343-352 (2010)
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6. Synthetic Sweat: ISO 3160/2 comprising of 20g/l NaCl, 17.5 g/l NH4Cl, 5 g/l Acetic Acid and 15 g/l Lactic Acid; pH adjusted to 4.7 by NaOH).
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8. P Hoessel, M Pierobon and C Wood, Polyquaternium-68: More than Hair Styling, SOFW 131 19-29 (2005).