Selection of surfactants for detergent use in cosmetics may be a serious issue. These surfactants must have not only high detergency but also low skin irritation and proper feeling in use. Understanding on adsorption phenomena of surfactants to hair and skin would bring about a progress on desirable detergent formulations. This review briefly surveys majour surfactants for shampoos and rinses on the Japanese market. The basic mechanisms of surfactant adsorption on hairs and proteins are then described.

View full abstract

We can keep our skin clean with a facial cleanser by removing excessive sebum, peroxide lipids, airborne solids adsorbed on our skin and so forth. The factors to consider in development of facial cleansers are functions, safety for skin and how-to-use. As each point is closely related to each other, it is impossible to be satisfied with the quality of facial cleansers whichever of three factors is lack. Also most influential ingredient to three factors is the surfactant which is main washing ingredient in facial cleansers formula. Therefore it is the best method for R & D of ideal facial cleansers that each factor is progressed harmoniously by use of the properties of surfactant. In this paper, Some main studies about each factor are picked out, and refer to ideal facial cleansers.

View full abstract

A typical synthetic resin thickener comprise of a crosslinked polyacrylic acid. It is generally prepared by crosslinking polyacrylic acid with allyl saccharose. This carboxyvinyl polymer is one of the most popular thickeners for cosmetics. It shows high ability of gelation, good transparency and pleasant odor. Since this carboxy-vinylpolymer structure is anionic, it can be blended with nonionic and anionic polymers. However it is incompatible with cationic and amphoteric polymers. This is a disadvantage since cationic and amphoteric polymers yield good textile, setting and water repulsion properties of hair respectively. Therefore, we carried research towards development of a new thickener compatible with both cationic and amphoteric polymers. As a result, we developed a new cationic polymer which is compatible with cationic and amphoteric polymers. Furthermore, it exhibits good thickening properties and high salt tolerance. This new cationic polymer is not only good thickener but also yields excellent adhesive and setting properties of hair. Styling gel formulation with this new cationic polymer, yielded a stable product without stickiness, flaking and excellent transparancy on hair.

View full abstract

Reproducible measurements have been desired in the spectral assessment of colored hair, because a rough surface and a heterogeneous internal structure of the colored hair causes the light scattering, which leads to deterioration of reflectance spectra of the colored hair. Since the photoacoustic effect indirectly detects optical absorption with an acoustic instrument such as a microphone, it is expected that photoacoustic spectroscopy (PAS) is little affected by the light scattering and thus provides the reproducible absorption spectra even for the colored hair. In this work, we measured PA spectra of the colored hair and compared them with the corresponding reflectance spectra. As the result, it was shown, as expected, that the PA spectra were obtained with good reproducibility and were little affected by the light scattering in comparison with the reflectance spectra. PAS is therefore applicable to the spectral assessment of the colored hair. On the other hand, the depthprofiling was attempted on cellophane samples with a laminar structure, and the colored hair by measuring the PA signal intensity at a constant wavelength as a function of the chopping frequency. The depth-profiling was successfully performed for the cellophane sample but not for the colored hair because of its circular crosssectional shape. Further improvement is necessary for the depth-profiling of the colored hair.

View full abstract

A partially hydrophilic crosslinked silicone was synthesized by the addition polymerization of a methylhydrogenpolysiloxane and a polyoxyethylene diallylether. The crosslinked silicone obtained can swell in dimethylpolysiloxane (silicone oil) forming a gel, and a large amount of water can also be successfully taken into the gel to form a stable W/O type emulsion. The W/O emulsion prepared using the synthesized crosslinked silicone was confirmed to have larger water droplets, and to contain a larger amount of water when compared with the emulsion prepared by the conventional silicone type W/O emulsifier (polyoxyethylene·methylpolysiloxane copolymer). The larger water droplets of the emulsion is well understood by the fact that the synthesized crosslinked silicone consists of dispersed particles with practically no soluble components, therefore has a lower ability of decreasing the interfacial tension between water and dimethylpolysiloxane (silicone oil). The stability of the emulsion in spite of its large water droplets is supposed by the following facts: 1) The interfacial film can be effectively formed by the dispersed crosslinking silicone which orientates between water and dimethylpolysiloxane (silicone oil), because of its hydrophilic and hydrophobic moiety. 2) The crosslinked silicone entangles its polysiloxane chains in dimethylpolysiloxane-the outer phase of the emulsion, forming the network. Therefore the dimethylpolysiloxane (silicone oil) existing around the water loses its fluidity and stays in a gelling state. And the viscosity of the gel shows little temperature-dependence because of its polysiloxane chain structure. Hence, the water, the inner phase of the emulsion, will not coagulate and the emulsion is stable in a wide temperature range.

View full abstract

Evaluating human hair luster is important to develop hair-care products. Many methods to measure human hair luster have been proposed so far. However, they have some disadvantages: some method needs to cut subject's hair and some needs a long time of period. To solve these problems, a new device to measure human hair luster is developed. This new device has some excellent features: It can measure human hair luster accurately without cutting hair. The measurement is not affected by subject's hairstyle and/or color. The device needs extremely short time of period. The relationship between sensory data of human hair luster and the measurement has highly correlative coefficient, so the measurement by this new device is effective for evaluating human hair luster.

View full abstract

The stratum corneum functions not only by holding water but also by maintaining barrier properties that control transepidermal water loss (TEWL) and prevents permeation of foreign substances. Shaku et al. reported on the double functions of poly [2-methacryloyloxyethyl phosphorylcholine (MPC)]. Our investigation led to discovery of an additional beneficial property of poly (MPC) that acts as a barrier and prevents excessive transepidermal water loss of the skin and permeation of foreign substances into the skin. We carried out experiments to determine if poly (MPC) hydrogel membrane with these barrier functions would be beneficial for troubled skin with weakened barrier function. We found that the skin condition of the subjects who had skin troubles before treatment experienced significant improvement after using of the experimental sample containing poly (MPC), and that the average surface area of corneocyte used to test barrier function was significantly increased. It appears that the weakened corneal barrier function was repaired by the formation of a hydrogel membrane on the skin, and the stratum corneum was restored to its healthy normal state. It is suggested that the hydrogel membrane formed by poly (MPC) functions like the corneum and acts as an effective barrier to prevent absorption of foreign substances and to regulate the transepidermal water loss.

View full abstract

A goniophotometer has ordinarily used to evaluate color and texture of subject. However, this method gives vast effort and a long time to measure, since incident and reflective angles must be changed in many a time. Moreover, since only one point of subject can be measured, it is actually impossible to obtain two-dimensional information which are needed to evaluate texture. To overcome these disadvantages, the new and unique method to evaluate color and texture of subject simultaneously is proposed. By recording images with multiple optical filters and a CCD camera, reverse calculating of obtained strength of reflective light can realize to measure spectral reflectance whole over the subject's surface simultaneously. A new device has been constructed based on our theory and tested on foundation painted on a sphere. The device could measure spectral reflectance at over 16000 points on the subject's surface at once. Moreover, changing high compositions of power spectrum given in specific wavelength using FFT could evaluate texture of subject. Clearly, the proposed method offers significant advantages over conventional methods.

View full abstract

The determination of estradiol and ethinylestradiol in cosmetic milk lotion and cream has already been established in the Standard Method of Analysis for Hygienic Chemist with Commentary 1995. But the harmful reagents against the human body such as chloroform and dichloromethane are used in the analytical procedures. In order to eliminate the harmful reagents and simultaneously protect the determination of estradiol and ethinylestradiol from the interference of parabens in the most part of cosmetics, we estimated a new and convenient method. The milk lotions or creams were condensed onto the water bath and then estradiol or ethinylestradiol in the residue was extracted with ethanol. The extract was analyzed by the high-performance liquid chromatography using the ODS column (TSKgel ODS_80TM, 4.6×150mm), the mixture of water, acetonitrile and methanol (3:1:1) as a mobile phase and the fluorescence detector (excitation and emission wavelength: 290 and 310nm). By the use of the analytical method above we made sure that estradiol and ethinylestradiol could be determined without interference of parabens as conservatives or other ingredients.

View full abstract