20 SKIN CARE Parameters


Contact angle on the artificial skin


More spreadable


Friction on the artificial skin


50wt% aq High friction


=Similar to water Light, Sheer texture


Figure 8: Contact angle and friction.


combination with other cosmetic ingredients. Due to its surfactant properties, cyclohexylglycerin affects the interfacial tension at the cell membrane of microorganisms. This allows some active ingredients, such as antimicrobials and preservative actives, to penetrate more effectively. In addition to providing effective preservation across a broad range of microbes, the ingredient is also effective over a wide pH range. Hexylglycerin is easier to solve in formulations and can be used for cosmetics, moisturisers and antimicrobial agents. It protects against the growth of microorganisms, including bacteria & fungi in personal care products and is an excellent booster for antimicrobial actives. Both cyclohexylglycerin and hexylglycerin have mild skin irritation, high water solubility and adequate antimicrobial effects.


Performance map Compared to other conventional glycols or parabens, hexylglycerin has higher water solubility and lower irritation, while it still is able to maintain an adequate antimicrobial effect. Even though cyclohexylglycerin’s antimicrobial activity is not that high, it has


Control (only keratin)


a much higher water solubility and lower skin irritation. Using the high water solubility of


hexylglycerin and cyclohexylglycerin, the total addition amount in formulations can be reduced. The described performance of cyclohexylglycerin and hexylglycerin is illustrated in the correlation chart between anti-microbial effect and water solubility or skin irritation (Fig 6).


Parameters texture modification with cyclohexylglycerin Water solution of cyclohexylglycerin is spreadable while keeping natural texture. Two parameters are used to illustrate the


texture: contact angle and friction, both tested in a solution of 5% of cyclohexylglycerin and 95% water. Cyclohexylglycerin has a rather low contact angle of 80° while other polyols have a contact angle of over 100°. A lower contact angle implies a better spreadability. Hence, cyclohexylglycerin is more spreadable than other polyols. Cyclohexylglycerin has texture


modifying properties. The friction factor of cyclohexylglycerin


Benzyl alchol 1%


is 1.1 higher than the one of buthylene glycol of 0.5-0.7. A solution of 50% cyclohexylglycerin and


50% water shows a high friction on artificial skin. A high friction factor implies the solution has a light or sheer texture, behaving similarly to water, whereas formulations with a low friction coefficient have a rather gooey or cushioning texture (Fig 7 and 8).


Penetration effect with keratin The penetration effect of cyclohexylglycerin is shown in the comparison graphics (Fig 9). Keratin is a widely known active ingredient mainly used in hair care products such as conditioners and treatments. While benzyl alcohol is commonly used as penetration enhancer, it often causes irritation on the skin and has a rather characteristic odour. Cyclohexylglycerin is a suitable, less irritating and odourless alternative to benzyl alcohol. The experiment takes place as follows:


First, keratin aq. with 1% is prepared with each glycol. After preparation, damaged hair is penetrated in each solution for 10 min. After the described time has passed, the hair is observed under a microscope. As


Cyclohexylglycerin 1%


Low friction =Gooey


Cushioning 5wt% aq


Figure 9: Tissue viability test. PERSONAL CARE GLOBAL August 2020


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