HIGH-PERFORMANCE SILICONE MICROEMULSIONS FOR HAIR CARE

Introduction

Today's hair care market has become a highly competitive and segmented market in which formulators must address a wide variety of hair types, cultures, regions and ethnic backgrounds. The needs of conscious and demanding young consumers and developing economies must be met. For this reason, the hair care industry must develop creative solutions every day. It is possible to create hair care products that strengthen hair with special silicones, help protect it, shield it from environmental stress, colour fading and heat stress, and even provide volume and frizz control. Silicones play an important role in the formulas of conditioners, shampoos, colorants and styling products.

Personalization in Hair Care

The concept of specialized hair care products is gaining increasing popularity because it allows consumers to express their individuality, and produces solutions to problems specific to hair type and desired style and condition. Special silicones are able to provide personalized solutions tailored to consumers' specific hair care needs. For example, hair care products on the market span a wide spectrum: normal, dry, curly, damaged, coloured, short, long, shiny and voluminous hair. Conditioning levels vary from intense to light, while benefits range from heat and colour protection to frizz control.

A Special Silicone for Hair Hydration

UV radiation, heat treatments, colouring chemicals, perms and straightening – even friction forces during daily brushing and styling – cause damage to hair strands. Regular washing of coloured hair can lead to colour fading. Hormonal irregularities and changes in sebum production in the body can result in dry, dull and grey hair with ageing. Hair hydration is one of the most popular claims used in today's hair care products. In fact, silicone does not hydrate hair. However, when silicone is added to rinse-off and leave-on hair care products, it gives the products a slippery texture that provides the sensation of hydrated hair. The definition of hair hydration differs from skin hydration. Hair hydration is expressed as easy combing of hair when both wet and dry, a healthy glossy appearance and the ability of hair to hold shape easily. With the help of special silicones, it is possible to formulate hair care products that can improve hair appearance. For example, by adding special silicones to shampoos and hair creams, it is possible to increase gloss and reduce colour fading in coloured hair.

Silicon Quaternium-17 in Microemulsions

High molecular weight silicones are well known for their hair conditioning and protection properties. However, because high molecular weight silicones are hydrophobic and highly viscous, they are difficult to formulate into hair care products. However, when made into an emulsion, high molecular weight silicones can be easily added to hair care formulations in the form of small droplets. This is more suitable for manufacturers, providing time and cost savings in production as well as improved efficiency. Microemulsions in which very small silicone droplets are thermodynamically stabilized are quite useful for the formulator. The droplets are transparent because they are smaller than the wavelength of visible light. This approach using fine droplets was used to develop a microemulsion based on high molecular weight Silicon Quaternium-17. The BRB 5446 microemulsion was subsequently created by emulsifying Silicon Quaternium-17 using Trideceth-5 and Trideceth-7. For this reason, the product does not contain polyether. The active silicone content in the microemulsion is approximately 15%. Furthermore, the BRB 5834 microemulsion was created by emulsifying Silicon Quaternium-17 using Laureth-4 and Laureth-23, with the gloss-enhancing effect of Phenyl Trimethicone. This product is a preservative and does not contain polyether. The active silicone content in the microemulsion is approximately 17%. With this new emulsion formulation, in addition to the product's superior conditioning properties, a moist feel, excellent wet and dry combing and ease of use have been provided. While suitable for all hair types, it is ideal for use in both rinse-off and leave-on products. Many tests were conducted to measure the performance of this product.

Performance Tests Combing Force Measurement

These studies demonstrate the conditioning performance of BRB 5446 (INCI: Silicone Quaternium-17, Trideceth-7, Trideceth-5) and BRB 6834 silicone microemulsions (INCI: Phenyl Trimethicone, Laureth-4, Silicon Quaternium-17, Laureth-23) according to measurements of wet and dry combing ease. Combing force measurements were performed using an MTT175 tensile testing instrument (Dia-Stron) before and after shampoo and conditioner applications. Tests were conducted on Caucasian hair type after undergoing colour removal twice to ensure all chemicals were removed from the hair. Combing force measurement results are shown in Figure 1. Both BRB 5446 and BRB 5834 microemulsions were observed to significantly reduce combing force in wet and dry combing tests after shampoo and conditioner compared to the control product. % Force reduction = [TCF (with product applied) - TCF (without product applied)] / TCF (without product applied) TCF = Total Combing Force (joules)

Figure 1. Wet and dry combing measurements (with Dia-Stron tensile testing instrument)

Heat Protection

Heat damage to hair occurs as a result of regular use of hair dryers, straighteners, curling irons and other heat-styling devices. These heat treatments damage the keratin structure of hair because they operate at temperatures between 180-230°C. Incorrect use of hot styling tools causes moisture to evaporate from the hair and damages the natural oils and proteins in its structure; this leads to dry, brittle and dull hair. For this reason, heat protection is of great importance in preventing damage. Special silicones provide heat protection due to their film-forming and low thermal conductivity properties. Untreated yellow Caucasian hair strands were lightened twice before testing. Subsequently, heat protection spray formulated with BRB 5446 microemulsion was applied to the hair strands and a straightener was applied 50 times at 230°C. Results are shown in Figure 2, with less damage observed in hair strands treated with heat protection spray compared to strands with no product applied. Silicon Quaternium-17 helps protect hair against heat and prevents hair breakage. It provides ease of combing, reduced breakage and a healthy appearance. The good results in heat protection of hair are explained by the transfer of Silicone Quaternium-17 from the microemulsion to the hair.

Figure 2. Heat protection test with straightener

Colour Protection

Today, consumers generally use hair dye to change their natural hair colour at various frequencies. Permanent hair dyes are also known as oxidative hair dyes. Hydrogen peroxide, as an alkalizing agent, swells the hair and helps dyes and dye catalysts reach the hair cortex. Red hair dye in particular has a high tendency to fade after shampooing and UV exposure; studies have shown that red dyed hair strands fade much faster compared to hair strands dyed black, blonde and brown. For this reason, colour fading is an important performance criterion not only for hair dyes but also for rinse-off and leave-on hair care products. Hair colour durability testing was conducted on untreated yellow Caucasian hair type. Red-coloured commercial dye was applied to the hair strands. Subsequently, the hair strands were washed with colour protection shampoo and then conditioner was applied; this procedure was repeated 15 times. Results were obtained after 5, 10 and 15 washes. Hair strand I is the sample with no product applied after dyeing, hair strand II is the sample with control shampoo and hair cream applied 15 times, hair strand III is the sample with shampoo and hair cream containing BRB 5446 microemulsion applied 15 times, and hair strand IV is the sample with silicone-free shampoo and hair cream applied 15 times. According to the results in Figure 3, a marked improvement in colour durability is observed in hair strands treated with shampoo and hair cream containing BRB 5446 microemulsion 15 times. The silicone microemulsion creates a hydrophobic surface on the hair, preserving colour vibrancy.

Figure 3. Colour protection with silicone microemulsion

I: Colour reference (untreated) II: Control III: Silicone Quaternium-17 (and) Trideceth-7 (and) Trideceth-5 IV: Silicone-free Hair Gloss Physical measurements show that phenyl groups attached to silicone increase hair gloss. In hair care, Phenyl Trimethicone is regarded as the gloss-giving standard and is frequently used as a reference material for test method validation and claim substantiation testing. Phenyl Trimethicone stands out with its organic compatibility, gloss, spreadability and reduced tackiness properties. By adding Phenyl Trimethicone to the BRB 5834 microemulsion, the hair's high gloss-giving capacity has been increased. Untreated yellow Caucasian type hair strands underwent bleaching twice before performance testing. Subsequently, a foaming hair cream containing BRB 5834 microemulsion was applied to the hair strands. Hair strand I is the sample treated with foaming hair cream not containing silicone microemulsion, and hair strand II is the sample treated with foaming hair cream containing 3% silicone microemulsion. In Figure 4, it can be seen that hair strand II treated with silicone microemulsion is glossier. Hair gloss is associated with healthy-looking hair and is widely used in hair care products.

Figure 4. Increasing hair gloss with silicone microemulsion

 

Application

BRB 5446 and BRB 5834 microemulsions are low viscosity liquids, making them easy to add to hair care formulations. They are water-soluble, suitable for cold processing and can be added to the formulation at the end of the process. They are suitable for clear and opaque, rinse-off and leave-on hair care products.

Conclusion

Rapidly growing global cosmetic trends are increasing demand for high-performance hair care products containing multifunctional raw materials such as silicone microemulsions. Silicone microemulsions have been specially developed to address specialized hair care applications, which have become a global need. Both BRB 5446 (INCI: Silicon Quaternium-17, Trideceth-7, Trideceth-5) and BRB 5834 microemulsions (INCI: Phenyl Trimethicone, Laureth-4, Silicon Quaternium-17, Laureth-23) are multifunctional hair conditioners and are effective in giving hair a soft appearance and feel. Compiled and Translated / Özge Yüksel Özel / Technical Business Development Manager / Personal Care / Azelis TR

References 1. Anthony J.O'Lenick Jr. Silicones for Personal Care 2nd Edition 2. Prapaporn Boonme, Natthida Pakpayat, Kanokwan Yotmanee, Sarinnart Kunlawijitrungsee, Duangkhae Maneenuan. Evaluation of Shampoos Containing Silicone Quaternary Microemulsion. Journal of Applied Pharmaceutical Science 01 (01); 2011: 59–63