• Korean Journal of Materials Research
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• v.34 no.2
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• pp.95-104
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• 2024

Nanoparticles are commonly used to avoid the opaque white color of TiO₂ based sunscreen. However, a dispersing agent is typically required because of the tendency of the nanoparticles (NPs) to agglomerate. Stearic acid is one kind of dispersing agent often used for sunscreen products. However, according to the MSDS data sheet on stearic acid, stearic acid is highly hazardous to aquatic life and causes irritation on human skin. To avoid this problem, in this study a safer organic dispersing agent extracted from Korean seaweed has been studied to disperse TiO₂ nanoparticles, and further use as an active agent in sunscreen products. The presence of phytochemicals in seaweed extract, especially alginate, can disperse TiO₂ nanoparticles and improve TiO₂ dispersion properties. Results show that seaweed extract can improve the dispersion properties of TiO₂ nanoparticles and sunscreen products. Reducing the agglomeration of TiO₂ nanoparticles improves sunscreen properties, by making it less opaque white in color, and increasing UV protection value. It was also confirmed that adding seaweed extract into sunscreen products had no irritating effects on the human skin, making it more desirable for cosmetics application.

• Journal of the Society of Cosmetic Scientists of Korea
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• v.37 no.3
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• pp.227-236
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• 2011

The new sunscreen agent, methoxycinnamidopropyl polysilsesquioxane, is manufactured as polymeric particles with an organic/inorganic hybrid composition. We have already reported the manufacturing method, physical properties, and sunprotection effects of methoxycinnamidopropyl polysilsesquioxane. In this study, we evaluated the photochemical properties and photostabilities of methoxycinnamidopropyl polysilsesquioxane that has the same functional group as a typical organic sunscreen agent, ethylhexyl methoxycinnamate (EHMC). Using the correlation of UV absorbance and fluorescence, we studied photostabilizers to enhance the photostability of methoxycinnamidopropyl polysilsesquioxane. Finally, we confirmed that octocrylene, ethylhexyl methoxycrylene, and bis-ethylhexyloxyphenol methoxyphenyl triazine were good photostabilizers for methoxycinnamidopropyl polysilsesquioxane.

• Journal of the Society of Cosmetic Scientists of Korea
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• v.22 no.2
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• pp.89-98
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• 1996

A novel polymeric sunscreen agent was developed. It was prepared by the coupling reaction of 2-ethylhexyl 4-hydroxycinnamate with poly vinylbenzyl chloride(PVBC, average MW 6,500). In this reaction the reactivity was mostly affected by catalyst. In the absence of catalyst the yield was approximately 55% and in the presence of tetrabutylammonium bromide the yield was about 65%, but in the presence of tetrabutylammonium iodide the yield was 100% to give a average molecular weight 20,000 polymeric sunscreen agent. There were no side reactions, and its structure and purity were confirmed by various analytical methods, such as NMR, IR, and so on. UV radiation absorption efficiency is more than 70% compared with that of octyl methoxycinnamate. The solubility in polar oil, for example C12-15 alkylbenzoate and caprylic/capric triglyceride, is more than 50%. It showed high stability in the time course of test including acceleration test. This polymer is safe to skin because of poor permeability to skin, no side products in the process of preparing, and easy elimination of excess starting materials.

• Journal of the Society of Cosmetic Scientists of Korea
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• v.45 no.3
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• pp.237-254
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• 2019

This study is focused on the effect of sodium stearate, which is a hydrophilic gelling agent affecting on the hardness of O/W solid sunscreen cosmetic. The sunscreen of the O/W (oil in water) type is stable, good in use, and relatively easier to stabilize than the sunscreen of the W/O (water in oil) type. Methods for increasing the stability by using emulsifiers, electrolytes, and wax or oil have been studied for solid sunscreen. This study was intended to develop a solid sunscreen stabilized by increasing the hardness using sodium stearate as an O/W type containing more than 40% moisture. Response surface methodology (RSM) was used to analyze the factors affecting the hardness of cosmetics, and sodium stearate, polyol and oil were used for each factor. The hardness and the reaction value was measured using a rheometer. As a result, sodium stearate showed a meaningful value (p < 0.05) among the three factors affecting hardness. In addition, the use of sodium stearate as a hydrophilic gelling agent increased the usability and stability of the solid sunscreen.

• Journal of the Korean Applied Science and Technology
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• v.35 no.3
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• pp.985-1001
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• 2018

In this study, we tried the various experiments using the emulsifier, electrolyte, stabilizer and gelling agent in order to improve a stability of low viscosity W/O emulsion. As a result, when we used polyglyceryl-4 diisostearate/polyhydroxystearate/sebacate as a main emulsifier, PEG-30 dipolyhydroxystearate and cetyl PEG/PPG-10/1 dimethicone as a co-emulsifier for stable emulsification system, 0.5 % sodium chloride as an electrolyte, 1 % distearyldimonium chloride as a stabilizer, 0.5 % glyceryl behenate/eicosadioate as an oil gelling agent, emulsion particle is the best. Also, we got the stable and low viscosity W/O emulsion maintained at a constant viscosity at 2,000 cps or less. In addition, we were able to examine the possibility of development of low viscosity fluids type sunscreens with excellent feeling and stability through the application of inorganic sunscreen agents.

• Journal of the Society of Cosmetic Scientists of Korea
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• v.24 no.3
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• pp.38-44
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• 1998

The skin permeation and the skin primary irritation of two UV filters from caprylic capryl triglyceride (oil), oil in water (O/W) and water in oil (W/O) emulsions, were evaluated. We selected octyl moth-oxycinnamate (OMC) broadly used in cosmetics and polymeric sunscreen agent (PSA, average MW: 2,000) synthesized by the coupling reaction of 2-ethylhexyl 4-hydroxycinnamate with poly vinylbenzyl chloride, as model UV filters. For in vitro skin permeation experiments, Franz diffusion cells (effective diffusion area:1.766cm) and the excised skin of female hairless mouse aged 8 weeks were used. Oil or emulsion containing UV filters was applied in the donor compartment. The skin primary irritation was evaluated with fe-male guinea pigs (8-10 weeks,350-400 g). In oil and emulsions, the skin permeability and the skin primary irritation of PSA were lower than those of OMC. The skin permeability of UV filters was lower when they were in oil-in-water emulsion (OIW) than water-in-oil emulsion (W/O). We suggest that O/W system would be more useful when compared with W/O system, and PSA could be a good candidate for a future sunscreen agent for reducing the skin irritation.

• Journal of the Korean Applied Science and Technology
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• v.31 no.3
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• pp.422-439
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• 2014

In this study, we measured the effects of UV protection efficiency of the polarity of oil, the type of emulsion, the viscosity of product, the type of thickener and light stabilizer in sunscreen. As a result, even higher polarity of the oil, UV protection efficiency is measured high (Butyloctyl salicylate: SPF 44.10, PA 7.93). In case of low, it was measured low conversely (Dimethicone: SPF 16.40, PA 5.57). In case of emulsion types, UV protection efficiency of W/O emulsion which organic sunscreen agent is based in the outer phase is measured higher than O/W emulsion. According to increasing of viscosity, UV protection efficiency tends to increase proportionally. However, the size of emulsion particles and the kinds of thickener has no effect to UV protection efficiency. Also light stabilizer was found to be an important factor affecting the UV protection efficiency. As a result, it is able to improve UV protection efficiency and it has potential which improve the economical effect of the sunscreen without increasing sunscreen agents.

• Journal of the Society of Cosmetic Scientists of Korea
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• v.47 no.4
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• pp.273-280
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• 2021

The water resistance is important factor for sunscreen formulations. Generally a sunscreen cream was formulated by a water-in-oil (W/O) emulsion. In the W/O emulsion system, silicone oils are added to improve the texture of formulations. Silicone oils have low compatibility with organic sunscreen agent, causing problems with the stability in emulsion. In this study, the compatibility between various oils in the W/O emulsion was derived numerically using Hansen solubility parameter (HSP) at first. HSP is represented a dispersion degree, a polarity, and a hydrgen bond in a composition. In this study, various emulsions were prepared according to the types of oils with different HSP values and then monitored by a viscosity and morphology according to the time and temperature. The HSP values of components and the experimental results have similar activities for the stability of emulsions. HSP made it easy to select oil with high compatibility. When the compatibility of the oil phase in the W/O emulsion was high, the viscosity change over time was small. The stability was improved under the freeze-thaw cycle (-15 ℃ ~ 45 ℃). In the future, if the composition of the ingredients is optimized through HSP, it is expected that it will be helpful in the development of W/O type sunscreen formulations that are excellent in use and stability.

• Proceedings of the Korean Society of Toxicology Conference
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• 2003.10b
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• pp.131-131
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• 2003

Benzophenone is an UV-absorbing agent that has been used in industry and medicine for more than 30 years. Its twelve derivatives, designated benzophenone-1 through benzophenone-12, are widely used today in cosmetic products as a photostabilizer, a sunscreen in lotions, and hair sprays to protect the skin and hair from UV irradiation.(omitted)

• Journal of the Society of Cosmetic Scientists of Korea
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• v.37 no.2
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• pp.137-141
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• 2011

Sunscreen is divided into the organic agent of UV absorption and inorganic agent of reflection. These are evaluated by sun protection factor (SPF) in-vivo test requiring high cost and time, while in-vitro tests are adopted commonly because of short test time, easy result collection. Generally, test method of SPF use SPF 290a by UV-vis spectrometer. The evaluate by SPF 290 has low reproducibility. Although analysis using UV-vis spectrometer has high reproducibility, it is hard to separated results of transmission, adsorption, and reflection. In this study, suggested method of elipsometer has some merit such as high reproducibility, easy separation of transmission/adsorption/re- flection, analysis using various incident angle. We tested the validity of elipsometer for SPF measurement, using commercially available sun-block (SPF 50).