NATURAL OIL EMULSIONS FOR PERSONAL CARE

Ercüment Gün Country Sales Manager Basildon Chemical Company Limited & KCC Corporation     Roxanne Smith Personal Care Technical Applications Manager Basildon Chemical Company Limited

Mark Ghafoor Technical Manager Basildon Chemical Company Limited

John Francis Technical Liaison Manager Basildon Chemical Company Limited HW Kim Technical Director Personal Care Division KCC Corporation H-J Cho Assistant Technical Manager Technical Analysis Team Personal Care Division KCC Corporation S-J Park Assistant Technical Manager Personal Care Division KCC Corporation Organic and Natural Summary: The formulator's ability to correlate the fundamental chemical behavior of an active ingredient with the consumer's perceived experience in the finished product enables better creation, modification and development of formulation options. KCC Basildon investigated the effects of the new Argan oil emulsion SeraShine® EM 801 in both hair and skin care formulations. For this purpose, analytical techniques were selected that best matched the physical properties of the emulsions with the desired "tactile" sensation. This paper discusses the benefits of emulsification (stability, particle size, active loading) on parameters relevant to the application (surface effects, feel, combing, texture). X-ray Photoelectron Spectroscopy (XPS) was used to evaluate the penetration of the Argan oil emulsion into hair fibers in hair care. Scanning Electron Microscopy shows the textural surface of hair when emulsion is used to treat hair strands. In parallel, wet and dry combing studies demonstrated the benefit of particle size optimization of the active oil achieved through emulsification. An emulsion particle size of 2.0 μm (D50) provides superior combing performance compared to pure and non-emulsified Argan oil. The results obtained show that when using the SeraShine® EM 801 emulsion, only half the amount is required to achieve equal combing benefit with pure Argan oil; that is, only 1% SeraShine® EM 801 is needed compared to 2% pure Argan oil. Improvement in combing was detected for both shampoo and hair conditioner formulations. However, in skin care products, rheological Oscillation Stress Sweep experiments showed that emulsification provides a more stable formulation. When using SeraShine® EM 801 compared to pure Argan oil, the product has a longer shelf life. It is also observed that formulations using pure Argan oil can typically become heterogeneous during use, i.e., during friction on the skin. When Argan oil is used in the form of the SeraShine® EM 801 emulsion, this instability is greatly reduced. Introduction Argan oil is produced from the kernel of the Argan tree native to Morocco. It is rich in tocopherols, squalene and fatty acids, containing 45-50% monounsaturated fatty acids. It has gained significant popularity in the cosmetics industry for more than the past 10 years and continues to be highly fashionable. However, there are some problems associated with pure Argan oil: • Discoloration of formulations due to dark amber color. • Difficulties during emulsification. • Degradation in sunlight. • Degradation at temperatures above 40°C. • pH sensitivity in surfactant systems. It was hypothesized that by emulsifying Argan oil, these and similar disadvantages could be improved. Many studies in the literature show that natural oils can penetrate into hair fibers, providing personal care products with multifunctional interactions with the surface layer that cannot be achieved with synthetic alternatives [1] [2] [3] [4] [5]. While coconut, olive and sunflower oils have been proven to penetrate, there is less evidence for Argan oil. Additionally, the use of emulsified natural oil in skin care formulations results in tactile experiences not possible when using pure oil. The Argan oil emulsion examined in this study is SeraShine® EM 801. It contains 52% organic, deodorized Moroccan Argan oil, INCI: Argania Spinosa (Argan) Kernel Oil (and) C12-14 sec-Pareth-5 (and) C12-14 sec-Pareth-9 and particle size <2.0 μm (D50). Combing Studies As standard practice, combing studies are conducted to evaluate new personal care products. The combing study showed that the Argan oil emulsion provided greater improvement in combing when compared to pure Argan oil in shampoo, see Figures 1 and 2, in fact pure Argan oil had a negative effect on combing results when used in shampoo.

Figure 1. Dry combing results in shampoo comparison

Figure 2. Wet combing results in shampoo comparison Improvement in combing was detected when emulsified Argan oil was used for both shampoo and hair conditioner formulations. In this way, we have demonstrated that by emulsifying the oil, multifunctional and effective products can be created. It is thought that by adjusting the particle size of the emulsion to approximately 2 μm, the accumulation of the active ingredient on hair is improved, which in turn leads to better combing. Additionally, Argan oil can also penetrate into the hair fiber. Figure 3. Dry combing results in hair conditioner comparison Figure 4. Wet combing results in hair conditioner comparison Hair Fiber Surface Imaging with SEM In a two-stage process, namely in separate hair samples washed with control shampoo only and with shampoo containing SeraShine® EM 801, a hair combing method was followed and the effect on surface textures was investigated. A significant difference in surface structures was expected to explain the improvements obtained in 45% dry combing and 17% wet combing (Figures 1 and 2). SEM images of hair were compared after washing with 2% active in control shampoo or SeraShine® EM 801 shampoo (Figures 6 and 7). However, the images show a minor change in hair surface texture when washed with shampoo containing SeraShine® EM 801 compared to control shampoo. Therefore, it is believed that the penetration of Argan oil into hair has a more pronounced effect on combing than initially expected.

Figure 6. SEM images of hair washed with control shampoo

Figure 7. SEM images of hair washed with shampoo containing 2% SeraShine® EM 801

Skin Care To understand the effects of the Argan oil emulsion in skin care applications, rheology and tribology experiments were conducted by comparing skin creams using pure Argan oil and SeraShine® EM 801 at 2% active loading. Oscillation Stress Sweep From the oscillation stress sweep (Figure 9) of the two creams, a significant difference in structure is observed. The 2% pure Argan oil cream is firmer (higher complex modulus curve) and stronger (higher yield stress). This study showed that emulsification leads to a decrease in yield stress and complex modulus. For this reason, compared to pure Argan oil, creams using SeraShine® EM 801 show a softer initial feel and easier spread properties.

Figure 9. Comparison of oscillation stress sweep results for creams containing 2% SeraShine® EM 801 and pure Argan oil

The oscillation stress also showed that the cream formulated with pure Argan oil tends to destabilize; during the experiment the sample phase separated due to the effect of shear stress as seen in Figure 10. Phase separation resulting from the friction applied for spreading can be perceived as a negative tactile experience.

Figure 10. Shear stress test images of creams containing 2% Argan oil (left), 2% EM801 (right)

Conclusion This study has demonstrated that SeraShine® EM 801, the emulsified form of Argan oil, can be used as a product that provides and enhances benefits in both hair and skin care applications. By keeping the particle sizes of the emulsion controlled, properties are achieved in both shampoo and hair conditioner that cannot be obtained using pure Argan oil for wet and dry combing. ToF-SIMS (*) measurements showed homogeneous distribution of SeraShine® EM 801 on hair surfaces without buildup after repeated washing. XPS(*) measurement, together with hair combing and SEM results, provided the first supporting evidence that Argan oil can penetrate into hair fibers. SeraShine® EM 801, as shown in both rheologies, has different tactile characteristic properties compared to Argan oil for formulating skin creams. Studies also showed that creams produced with SeraShine® EM 801 have longer stability compared to pure Argan oil. (*) (*)For detailed information, you can contact Basildon Chemical Company Limited. References [1] V. Gode, "Quantitative measurement of the penetration of coconut oil into human hair using radiolabeled coconut oil," Journal of the Society of Cosmetic Chemists, p. 27, 2012. [2] K. Keis, "Investigation of penetration abilities of various oils into human hair fibers," Journal of the Society of Cosmetic Chemists, pp. 283-295, 2005. [3] A. S. Rele, "Effect of coconut oil on prevention of hair damage. Part I," Journal of the Society of Cosmetic Chemists, pp. 327-339, 1999. [4] A. Rele, "Effect of mineral oil, sunflower oil, and coconut oil on prevention of hair damage," Journal of the Society of Cosmetic Chemists, pp. 175-192, 2003. [5] S. B. Ruetsch, "Secondary ion mass spectrometric investigation of penetration of coconut and mineral oils into human hair fibers: Relevance to hair damage," Journal of the Society of Cosmetic Chemists, pp. 169-184, 2001.