Organic and Natural
Abstract:
Linking fundamental chemical behaviours of an active ingredient to the consumer’s tactile experience of a finished formulation enables the formulator to better create, modify and enhance their product offerings.
KCC Basildon have studied the effect of their novel Argan oil emulsion, SeraShine® EM 801, in both hair and skin care formulations. Analytical techniques have been selected that best link physical properties of these emulsions to a desired “tactile” response.
Here we discuss the benefits of emulsification (stability, particle size, active loading) to application relevant parameters (surface effects, feel, combing, texture). In hair care X-ray Photoelectron Spectroscopy (XPS) was used to assess the penetration of Argan oil emulsion into hair fibres.
Scanning Electron Microscopy shows the textural surface of hair when the emulsion is used to treat hair tresses. In parallel, wet and dry combing studies have shown the benefit of particle size optimisation of the active oil, achieved by emulsification.
An emulsion particle size of 2.0 μm (D50) provides superior combing performance compared to neat un-emulsified Argan oil.
The data demonstrates that by using SeraShine® EM 801 emulsion, half the active loading is required to achieve equivalent combing benefits compared to neat Argan oil – only 1% SeraShine® EM 801 is required compared to 2% neat Argan oil. Improved combing is found for both shampoo and conditioner formulations.
In skin care products, rheological Oscillation Stress Sweep experiments have demonstrated that emulsification yields a more stable formulation. Shelf life is superior when SeraShine® EM 801 is used compared to neat Argan oil.
It has also been shown that formulations using neat Argan oil can often become heterogeneous during use i.e. during rubbing onto the skin. By using the SeraShine® EM 801 Argan oil emulsion this instability is greatly reduced.
Introduction
Argan oil is produced from the kernals of the Argan tree, which is indigenous to Morocco. It is rich in tocopherols, squalene and fatty acids, containing 45–50% monounsaturated fatty acids.
It has gained huge popularity in the cosmetic industry over the last 10+ years and remains very fashionable. However, neat Argan oil is prone to the following problems:
• Discolouration of formulations due to its deep amber colour.
• Difficulty during emulsification.
• Degradation in sunlight.
• Degradation at temperatures above 40°C.
• pH sensitivity in surfactant systems.
By emulsifying Argan oil it was hypothesised that such drawbacks could be ameliorated. A good body of work in the literature demonstrates that natural oils can penetrate hair fibres, yielding personal care products that provide multifunctional interactions with the substrate that is not achieved with synthetic alternatives
[1] [2] [3] [4] [5]. Penetration by coconut, olive and sunflower oils have been demonstrated, less evidence is available for Argan oil. In addition, the use of emulsified natural oil in skin care formulation opens up tactile experiences not possible when a neat oil is used.
The Argan oil emulsion studied in this work is SeraShine® EM 801. It contains 52% organic, deodorised Moroccan Argan oil, with INCI: Argania Spinosa (Argan) Kernal Oil (and) C12-14 sec-Pareth-5 (and) C12- 14 sec-Pareth-9 and a particle size of <2.0 μm (D50).
Combing Studies
As standard, combing studies are used to screen new personal care products. The combing study demonstrated that the Argan oil emulsion yields greater improvement in combing compared to neat Argan oil in shampoo, see Figures 1 and 2, in fact, the neat Argan oil mainly has a detrimental effect on combing results when used in shampoo.
Figure 1. Dry combing results comparing shampoos
Figure 2. Wet combing results comparing shampoos
When tested in conditioners the results show that for wet combing, Figure 4, SeraShine® EM 801 consistently out performs neat Argan oil at all loadings. In comparison for dry combing, Figure 3, whilst there can be an improvement in combing if neat Argan oil is used, there is a benefit to using the emulsification route.
The benefit comes from the fact that a lower active loading can be used and still achieve the same dry combing improvement.
The data demonstrates that by using SeraShine® EM 801 emulsion, half the active loading is required to achieve equivalent dry combing benefits compared to neat Argan oil – only 1% SeraShine® EM 801 is required compared to 2% neat Argan oil.
Improved combing is found for both shampoo and conditioner formulations when an emulsified Argan oil is used. Therefore, we have shown that emulsifying the oil leads to a product that can be utilised more ubiquitously.
It is thought that by controlling the particle size of the emulsion to ~ 2 μm the deposition of the active on the hair is improved, leading to improved combing. In addition, the Argan oil may also penetrate the hair fibre.
Figure 3. Dry combing results comparing conditioners
Figure 4. Wet combing results comparing conditioners
SEM for Imaging Hair Surface
An investigation of the surface texture of hair samples after treatment at the two stages during a combing protocol was undertaken, i.e. hair washed only with control shampoo and after washing with shampoo containing SeraShine® EM 801.
It was anticipated that an obvious difference in surface structure would explain the improvements seen, i.e. 45% improvement dry combing and 17% improvement wet combing (Figures 1 and 2) SEM images of hair after washing in control shampoo or SeraShine® EM 801 shampoo, at 2% active, were compared (Figure 6 versus Figure 7).
The images show there was only a minor change in surface texture of the hair when washed with the shampoo containing SeraShine® EM 801 compared to the control shampoo. Therefore, it was considered that Argan oil penetration into the hair was having a more pronounced effect on combing than first anticipated.
Figure 6. SEM images of hair washed with control shampoo
Figure 7. SEM images of hair washed with shampoo containing
SeraShine® EM 801 at 2% active loading.
Skin Care
In order to understand the effect of emulsification of Argan oil in skin care applications, rheology and tribology experiments were conducted comparing a skin cream with either neat Argan oil or SeraShine® EM 801 at 2% active loading.
Oscillation Stress Sweeps
A clear difference in structure is seen from the oscillation stress sweeps, Figure 9, for the two creams. The 2% neat Argan oil cream is more rigid (higher complex modulus plateau) and stronger (higher yield stress).
This study showed that, emulsification led to a reduction in yield stress and reduction in complex modulus. This equates to a softer initial touch and less work to spread a cream made from the SeraShine® EM 801 compared to neat Argan oil.
Figure 9. Oscillation stress sweep results comparing creams with
SeraShine® EM 801 and neat Argan oil at 2% active
The oscillation stress sweeps also highlighted that the cream formulated with neat Argan oil was prone to destabilisation; the sample became phase separated due to the effects of shear during the experiment.
This is depicted in Figure 10. Such phase separation under the influence of shear is likely to be perceived as a negative tactile experience.
Figure 10. Images taken of 2% Argan Oil (left) and EM801 (right) after shearing
Conclusions
This work has shown that emulsifying Argan oil yields a product, SeraShine ® EM 801, that can be used to enhance benefits in both hair and skin care applications.
By controlling particle size of the emulsion improvements in combing have been demonstrated in both shampoo and conditioner, for wet and dry combing – something not achieved by using neat Argan oil.
ToF-SIMS (*) has shown the homogenous deposition of SeraShine® EM 801 on hair surfaces, without build up over multiple washes. XPS (*) profiling, in conjunction with combing and SEM results, has shown initial supporting evidence that Argan oil can penetrate hair fibres.
SeraShine® EM 801 has also been used to formulate skin creams with different tactile parameters compared to neat Argan oil, demonstrated through both rheology. The studies also highlighted the improved stability of creams manufactured with SeraShine ® EM 801 versus neat Argan oil. (*)
(*)Please contact Basildon Chemical Comp. Ltd. for detailed information.
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
Technical Asst. Mng.
Technical Analysis Team
Personal Care Division
KCC Corporation
S-J Park
Technical Asst. Manager
Personal Care Division
KCC Corporation
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 Chemsits, 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.
