AB Specialty Silicones set out to manufacture a cosmetic ingredient that is high-performing, multi-functional, compliant with EU regulations and easy to formulate with. Can one ingredient ‘have it all’?
The purpose of this paper is to illustrate the development of a TMS resin blend emulsion, its extreme ease of formulation, regulatory compliance, and performance as an anti-frizz agent. The resin blend, Phenyltrimethicone (and) Trimethylsiloxysilicate, has proven to outperform the industry staple, Cyclopentasiloxane (and) Trimethylsiloxysilicate. The emulsion of the same blend maintains an equal level of performance as its non-emulsion resin blend counterpart, when tested for efficacy both as an anti-frizz agent and when formulated into an anti-frizz formulation.
The hair care industry is known for its innovation and continuous efforts to improve ingredients and their benefits. For this reason, multi-functional ingredients have gained in popularity. They also meet other market demands, such as ease of formulation and meeting EU regulatory requirements. With this in mind, we set out to manufacture a cosmetic ingredient that met as many of these needs as possible: high performing, multi-functional, compliant with EU regulations, and easy to formulate with. Can one ingredient have it all?
Where it all began: the resin blend
Although the use of trimethylsiloxysilicate (TMS) resins as a multi-functional ingredient in hair applications has a long history of safety, the handling of the neat resins can cause issues in manufacturing, due to the generation of dust and a lengthy dissolution time. These negative factors led to the introduction of resin blends, where the neat resin is already incorporated into a carrier fluid that can be volatile or nonvolatile and varies depending on the desired benefits.
Regulatory compliance & performance
Practically, the next step was to determine how these materials could overcome the regulatory hurdle. Growing environmental safety concerns surrounding cyclopentasiloxane, commonly known as D5, warranted testing to determine if the blends using volatile carriers had similar performance while avoiding pending regulatory issues. The results for the cyclic-free resin blend with the INCI name Phenyltrimethicone (and) Trimethylsiloxysilicate showed that it outperformed its D5 counterpart in all testing including as an anti-frizz additive. This particular blend adds multiple benefits to both hair and skin care formulations. Furthermore, with 0.1% w/w D5, Cyclopentasiloxane (and) Trimethylsiloxysilicate is a suitable ingredient option for formulators who want to reduce or eliminate cyclopentasiloxane from their products due to regulatory concerns, while also taking advantage of improved benefits over what are offered by a conventional resin or resin blend.
As a side note, various skin care testing showed that Phenyltrimethicone (and) Trimethylsiloxysilicate also outperformed the industry staple with the INCI name Cyclopentasiloxane (and) Trimethylsiloxysilicate with higher abrasion resistance, higher transfer resistance and higher cycles to breakthrough. These results show that Phenyltrimethicone (and) Trimethylsiloxysilicate has superior performance and make it a great option for applications where shine and organic compatibility are desired such as lipsticks, eye liners and sun care products. Further information and testing details are available in a previous publication.1
Room for improvement
Whereas Phenyltrimethicone (and) Trimethylsiloxysilicate eliminated the need for handling the neat resin, is high-performing and offers D5 regulatory compliance, there was still room for improvement. The R&D team then developed a cyclic free resin blend emulsion to further simplify formulating and manufacturing efforts – and then gauged its performance compared to the resin blend itself.
With anti-frizz performance as the initial benchmark, the resin blend, the cyclic free resin blend, the cyclic free resin blend emulsion as well as an anti-frizz formulation using the cyclic free resin blend emulsion underwent testing to determine their performance over a four hour period. Although resin blend emulsions are currently limited in choice and availability in the personal care marketplace, theoretically they should be a game-changer in terms of incorporating resins into water based formulations – which most hair and skin care products are. The big question needed answering though, is at what cost: would the resin blend’s superior performance be sacrificed for ease of formulation and manufacture when presented as an emulsion?
Manufacturing advantages of an emulsion
Emulsions are often developed to lessen a manufacturing burden, making the incorporation of multiple insoluble materials into a formulation more user-friendly as well as cost-effective. In this instance, since neither resins nor silicone fluids are innately soluble in water, adding them into aqueous formulations can be troublesome and present many manufacturing issues. These resin blend emulsions were specifically designed to overcome the manufacturing hurdle of combining multiple immiscible materials, including hard to handle resins, by creating an oil-in-water (O/W) emulsion. This emulsion can help ease formulating work because it can be added to oil-in-water emulsion-based formulations with cold mix processing, while also maintaining stability.
Functional advantages of an emulsion
Where resin blends are a great example of a multi-functional ingredient, the resin blend emulsion is an excellent example of one. Resin blend emulsions are easy-to-use since they are already ‘emulsified’ in water-based systems. Time and cost of development work can be reduced being that the ingredients are already emulsified and the addition of a surfactant is no longer necessary to create a homogenous product – the product is already formulated as a white, stable, emulsified material.
Resin blend emulsions can be added to existing water-based formulations to improve aesthetic properties as they feature all of the desirable benefits from low volatility, cyclic-free phenyltrimethicone and trimethylsiloxysilicate resins, along with the functionality and dispersability of an emulsion. The emulsified state also reduces the tackiness of the neat resin. Regarding hair care aesthetic benefits, resins are known as anti-frizz agents and for humidity resistance while Phenyltrimethicones offer enhanced shine, improved texture and a soft supple feel.
The big test
Anti-frizz test method
Testing was performed to determine the antifrizz performance of a control, a resin blend, a D5-free resin blend, a D5-free resin blend emulsion and an anti-frizz product formulated with a D5-free resin blend emulsion (Figure 2) using specific hair samples. The samples were measured hourly over a four-hour period.
Sample preparation
We prepared one-inch-wide hair samples (with clips) and calculated the weight of the hair by weighing the entire sample; then weighing the clip separately. The hair weight was finally determined by subtracting the weight of the clip from the total weight.
. Each hair sample was wetted completely, wrapped in a microfibre towel and ‘tapped’ dry.
Testing procedure
The designated amount of anti-frizz ingredient was then evenly distributed through the hair sample. One sample was left without any anti-frizz product and determined to be the control. The width of the hair sample was measured (Figure 2)
The hair samples were placed into a humidity chamber. Temperature set at 70°C, humidity at 20% to simulate a standard hair dryer. The hair samples were then measured every hour over a four-hour period.
Testing results
The results were calculated to determine the width of change in inches and the percentagechange over time.
As indicated in Figure 3, the hair sample that was treated with the cyclic-free resin blend, the resin blend emulsion and the anti-frizz formula containing the resin blend, emulsion had the best anti-frizz performance, presenting no change over the four hour test period.
Discussion
As the results show, the resin blend in an emulsified state has proven not to affect the superior performance of the cyclic free resin blend. What can be concluded from the results is that when used in an anti-frizz capacity, the resin blend emulsion is a high performing, multi-functional ingredient that is both regulatory compliant and easy to use, manufacture and formulate with. Potential cost savings are also a possibility due to less time being needed to prepare the ingredients for formulation and eliminating the steps of handling the neat resin and adding a surfactant since the material is already emulsified.
Being emulsified, the resin blend emulsion is ready to be added to existing waterbased formulations, on which many hair care products are based. Along with the emulsion and its ease of manufacture come the many desirable benefits that come with the blended materials including: anti-frizz, humidity resistance, volumiser, conditioning, shine, slip, treatment for dry and damaged hair, improved texture, imparts soft supple feel, enhanced shine, and is cyclic-free – making it regulatory compliant
What is next?
Resin blends also have a lot of benefits to offer for skin care formulations. Since one of the most desirable attributes of trimethylsiloxysilicate is its film forming properties, we will be testing another high performing resin blend emulsion, made from a Dimethicone (and) Trimethylsiloxysilicate blend. The results will show how well the emulsion holds up to the film forming testing showing number of cycles to breakthrough, and the abrasion and transfer resistance of a makeup setting spray.
Reference 1 King, Doug. “Novel Trimethylsiloxysilicate Blends and Their Use in Personal Care Applications.”, 19 August. 2019
