Characteristics of natural derived surface treated pigments for the achievement of SDGs
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Presented by: Reiichiro Tsuchiya
Introduction
Due to the high functional properties, surface treated pigments have been formulated into a lot of make-up cosmetics and sunscreen cosmetics. Various types of cosmetic pigments coated with various kinds of surface treatment agents, have been developed for improving water-resistance, dispersibility, tactile feelings, and so on. However, each type of surface treated pigments shows completely different characteristics depending on the chemical structures of each surface treatment agents. Therefore, it has been very important for cosmetic engineer, especially cosmetic formulators, to understand the behavior of each type of surface treated pigments in their formulations. Conventionally, because of the advantage of performance and costs, petrochemicals, such as silicone and alkyl silane, have been widely used as surface treatment agents. However, the public awareness concerning about global environment issues are recently enhancing. In 2015, sustainable development goals (SDGs) were adopted by United Nation and now almost all countries, companies and people in the world are working hard to accomplish SDGs. In the cosmetic field, the development of raw materials accordant with the concept of SDGs, especially biomass ingredients without using petrochemicals and the research and developments of biodegradable ingredients are greatly accelerating. Under this circumstance, several surface treated pigments using natural origin agents also have been developed. In this work, to reveal the characteristics of each type of surface treated pigments especially focused on natural surface treatments, we evaluated their mechanical properties, tactile feeling, and frictional properties.
Experiments
First, we measured mechanical properties, such as contact angle, particle size distribution, oil absorption and bulk specific gravity, of five types of natural surface treated titan dioxide: magnesium stearate (MS), lauroyl lysine(LL), polyglyceryl-2 tetraisostearate (PT), sodium dilauramidoglutamide lysine (SDL), mannosyl erythritol lipid (MEL) and three types of petrochemical surface treated titan dioxide: alkyl silane (AS), methylhydrogen polysiloxane (SI), isopropyl titanium triisostearate (TT). Secondary, the usability of each surface treated pigments was evaluated by tactile evaluation and frictional evaluations using a sinusoidal motion friction evaluation system. In addition to these evaluations, we investigated oil dispersibility and moisture effect of each type of surface treated pigments. Oil dispersibility evaluations were conducted using three kinds of cosmetic oils: squalene, caprylic/capric triglyceride and dimethicone.
Results
TT and PT whose chemical structure were including long-chain branched fatty acid esters show high dispersibility in all kinds of cosmetic oils. This result indicates that TT and PT treated pigments would be suitable for oil-based cosmetics, such as W/O liquid foundations and concealers. From tactile and frictional evaluations, the static friction coefficient of all kinds of surface treated pigments are decreased compared with non-treated pigment. AS and LL show moist and creamy touch feeling, while MS and SI indicates dry and light touch feeling. This result suggests that tactile impressions are induced by the alkyl chain length of surface treatment agents. SDL and MEL show similar characteristics, such as relatively low hydrophobicity, pickering emulsification ability, whereas their moisture effects are clearly different.
Conclusion
These results reveal that characteristics of each type of surface treated pigments will be greatly affected by chemical structure of each surface treatment agents. From these results, we succeed in classifying these surface treated pigments by their functions and tactile feeling. Furthermore, these knowledges would be very useful for cosmetic formulators who would like to prepare the new natural cosmetic formulations without using conventional petrochemicals.
Due to the high functional properties, surface treated pigments have been formulated into a lot of make-up cosmetics and sunscreen cosmetics. Various types of cosmetic pigments coated with various kinds of surface treatment agents, have been developed for improving water-resistance, dispersibility, tactile feelings, and so on. However, each type of surface treated pigments shows completely different characteristics depending on the chemical structures of each surface treatment agents. Therefore, it has been very important for cosmetic engineer, especially cosmetic formulators, to understand the behavior of each type of surface treated pigments in their formulations. Conventionally, because of the advantage of performance and costs, petrochemicals, such as silicone and alkyl silane, have been widely used as surface treatment agents. However, the public awareness concerning about global environment issues are recently enhancing. In 2015, sustainable development goals (SDGs) were adopted by United Nation and now almost all countries, companies and people in the world are working hard to accomplish SDGs. In the cosmetic field, the development of raw materials accordant with the concept of SDGs, especially biomass ingredients without using petrochemicals and the research and developments of biodegradable ingredients are greatly accelerating. Under this circumstance, several surface treated pigments using natural origin agents also have been developed. In this work, to reveal the characteristics of each type of surface treated pigments especially focused on natural surface treatments, we evaluated their mechanical properties, tactile feeling, and frictional properties.
Experiments
First, we measured mechanical properties, such as contact angle, particle size distribution, oil absorption and bulk specific gravity, of five types of natural surface treated titan dioxide: magnesium stearate (MS), lauroyl lysine(LL), polyglyceryl-2 tetraisostearate (PT), sodium dilauramidoglutamide lysine (SDL), mannosyl erythritol lipid (MEL) and three types of petrochemical surface treated titan dioxide: alkyl silane (AS), methylhydrogen polysiloxane (SI), isopropyl titanium triisostearate (TT). Secondary, the usability of each surface treated pigments was evaluated by tactile evaluation and frictional evaluations using a sinusoidal motion friction evaluation system. In addition to these evaluations, we investigated oil dispersibility and moisture effect of each type of surface treated pigments. Oil dispersibility evaluations were conducted using three kinds of cosmetic oils: squalene, caprylic/capric triglyceride and dimethicone.
Results
TT and PT whose chemical structure were including long-chain branched fatty acid esters show high dispersibility in all kinds of cosmetic oils. This result indicates that TT and PT treated pigments would be suitable for oil-based cosmetics, such as W/O liquid foundations and concealers. From tactile and frictional evaluations, the static friction coefficient of all kinds of surface treated pigments are decreased compared with non-treated pigment. AS and LL show moist and creamy touch feeling, while MS and SI indicates dry and light touch feeling. This result suggests that tactile impressions are induced by the alkyl chain length of surface treatment agents. SDL and MEL show similar characteristics, such as relatively low hydrophobicity, pickering emulsification ability, whereas their moisture effects are clearly different.
Conclusion
These results reveal that characteristics of each type of surface treated pigments will be greatly affected by chemical structure of each surface treatment agents. From these results, we succeed in classifying these surface treated pigments by their functions and tactile feeling. Furthermore, these knowledges would be very useful for cosmetic formulators who would like to prepare the new natural cosmetic formulations without using conventional petrochemicals.