Eco-friendly Conditioning

Cationic quaternary ammonium compounds (quats) play a significant role in cosmetic formulations, particularly in hair care, due to their ability to interact strongly with the negatively charged surface of hair fibers. Conventional alkyl quats such as cetrimonium chloride (CTAC) and behentrimonium chloride (BTAC) are widely used as hair conditioning agents.  While they are effective at improving the sensory and manageability of hair, the negative environmental impact of alkyl quats is a growing concern, and many companies are now looking for alternative solutions that are more sustainable. 

Esterquats have emerged as a promising eco-friendly replacement for conventional alkyl quats in personal care products. Esterquats are biodegradable, have excellent conditioning properties, and are less toxic to the environment. Furthermore, esterquats offer several benefits, such as reduced static electricity, improved wet and dry combing, and enhanced hair shine. With increasing consumer demand for sustainable and environmentally friendly products, the eco-friendly nature of esterquats can be leveraged as a brand value for companies.

What are esterquats?

Esterquats are a type of cationic surfactant that is derived from the esterification of fatty acids with quaternary ammonium compounds. They contain ester bonds that link the fatty acid molecules responsible for conditioning hair with a cationic head group derived from amino alcohol, providing a strong affinity to hair fibers. Due to their susceptibility to hydrolysis based on pH and temperature, these ester bonds offer a genuine pathway for the surfactants to degrade, making esterquats readily biodegradable. When they decompose, they form a fatty acid soap and a small water-soluble cationic moiety that is no longer surface active, making them environmentally benign, particularly to aquatic organisms, even before further degradation.

Traditionally, esterquats have been derived from animal fats or tropical oils, such as palm oil, which has raised concerns about the sustainability of these ingredients. However, there are now ways to produce esterquats from non-tropical vegetable oils, offering a more sustainable alternative. Switching to vegetable oil-based esterquats not only addresses concerns about palm sustainability, but also promotes more sustainable practices in the personal care industry. Companies that prioritise sustainability and use alternative sources of esterquats are demonstrating their commitment to reducing their environmental impact and meeting the demands of conscious consumers.

One example of a vegetable oil-based esterquat is derived from rapeseed oil, which is abundant in many regions of the world and does not contribute to deforestation or habitat loss. This alternative source of esterquats can be manufactured through environmentally friendly processes, thereby reducing the overall environmental impact.

Modern esterquats are produced using low energy, low emissions processes that minimise the environmental impact. The production process uses less energy and produces fewer emissions than the production of traditional quats. This makes esterquats a sustainable choice for manufacturers who want to reduce their carbon footprint.

Development of Dioleoylethyl Hydroxyethylmonium Methosulfate

Esterquats are effective conditioning agents and moisturisers for personal care products. They are widely used in hair care products such as shampoos and conditioners to improve the texture and manageability of hair. Esterquats also provide excellent detangling properties and reduce static electricity, resulting in smooth and shiny hair. Additionally, they can be used in body care products such as lotions and creams to improve skin texture which makes skin feel soft, supple, and hydrated. Although esterquats are not typically promoted as emulsifiers for their main function, their natural emulsification properties enable them to blend well with other ingredients in personal care products, resulting in a smooth and uniform texture.

While esterquat technologies already exist, it is crucial to continue enhancing their conditioning performance, cost efficiency, and compatibility with other ingredients, while also ensuring compliance with a broad range of global chemical registration. Evonik has recently overcome the limitation by developing Varisoft EQ 90 (INCI: Dioleoylethyl hydroxyethylmonium methosulfate), which is a very cost-efficient conditioning agent with an improved sustainability profile.  

Dioleoylethyl hydroxyethylmonium methosulfate offers various sustainability advantages apart from being readily biodegradable. Being a 100 percent active liquid material, it eliminates the use of potentially harmful solvents and can be processed at ambient temperatures, resulting in significant energy savings compared to solid conditioning agents. Because it is derived from rapeseed oil, concerns about palm oil sourcing can be avoided. Moreover, it is versatile and can be incorporated into various formulations and application formats, such as conditioner rinses, conditioner masks, hair treatments, shampoos, shower gels, and leave-in sprays, thus simplifying the production process.

Conditioning Performance of Dioleoylethyl Hydroxyethylmonium Methosulfate

Dioleoylethyl hydroxyethylmonium methosulfate provides very good conditioning benefits on both wet and dry hair. An external testing institute conducted professional half-head tests on ten panelists with colored hair to evaluate the effectiveness of conditioners. The tests were performed by professional hairdressers, and the results showed that Varisoft EQ 90 outperformed the two market-standard alkyl quats, Cetrimonium Chloride (CTAC) and Behentrimonium Chloride (BTAC) in the most relevant parameters (Figure 2 and 3).

Enhancing the Sensory Experience

In hair and body wash formulations, dioleoylethyl hydroxyethylmonium methosulfate enhances skin feel properties. The results of a sensory hand wash test depicted in Figure 4 demonstrate that the incorporation of 1% Varisoft EQ 90 provides an immediate improvement in skin smoothness and softness after drying the hands, as well as a sustained effect three minutes after drying.

Formulation Compatibility for Optimal Shampoo Performance

Dioleoylethyl hydroxyethylmonium methosulfate is a compatible cationic conditioning ingredient for use in various shampoo formulations, including clear formulations. The inclusion of Varisoft EQ 90 in shampoo formulations has shown improvement in all parameters related to wet hair, as illustrated in Figure 5.

Conclusion

Esterquats are an excellent choice for manufacturers looking to create sustainable, functional, and high-quality hair care and body wash products. These compounds offer a range of sustainability benefits such as renewably sourced materials, biodegradability, and a low environmental impact. In addition to being eco-friendly, esterquats also offer functional benefits such as conditioning, emulsification, and, according to some studies, antimicrobial properties. Furthermore, the use of esterquats in personal care products aligns with consumer preferences for natural, safe, and effective formulations, thereby offering brand values that appeal to today’s customers. Esterquats that are derived from natural and renewable sources align with the growing trend of natural and organic products. 

In conclusion, the development of sustainable esterquats is a positive step towards reducing the environmental impact of the personal care and cleaning industries. These products deliver high performance, and effectiveness while reducing negative impacts on the environment and human health. Choosing sustainable esterquats is a step towards a more sustainable future for all.