Journal of the Japan Society of Colour Material
Online ISSN : 1883-2199
Print ISSN : 0010-180X
ISSN-L : 0010-180X
Volume 92 , Issue 10
Showing 1-4 articles out of 4 articles from the selected issue
Original Research Paper
  • Naoaki TOYODA, Toshihiko OKADERA, Hiroyuki ASANO, Hitoshi SAWADA, Tsuy ...
    2019 Volume 92 Issue 10 Pages 285-291
    Published: October 20, 2019
    Released: November 02, 2019

    In the cosmetic field, surface treatment for cosmetic powders has been used for the purpose of product stability, functionality and sense of use improving. The various treated powders are applied to powdery cosmetics such as powdery foundation in order to add the required texture. However, objective evaluation methods about sense of use for each treated powder have not been systematized. In this study, we investigated the correlation between sense of use and physical properties obtained from direct shear testing of the powder bed about four kinds of sericite powder with different surface treatment methods. As a result, internal friction coefficient μi and shearing cohesion τc were correlated with the smoothness and the moist feeling, respectively. Furthermore, it was found that the softness of surface treatment powder can be estimated by the value of stress relaxation ratio σsrr obtained from relaxation process after powder consolidation.

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Original Technical Paper
  • Yuji WAKABAYASHI, Makiko YONEHARA, Hidetoshi YAMABE, Shun YOSHIDA, Tos ...
    2019 Volume 92 Issue 10 Pages 292-298
    Published: October 20, 2019
    Released: November 02, 2019

    The effect of the concavo-convex surface profile of a transparent acrylic plate on haze and glossiness was experimentally investigated. The surface of the acrylic plate was shot blasted using glass beads to alter the surface roughness of one or both sides of the plate by changing the projection pressure. The surface texture was comprehensively evaluated by using 3D surface texture parameters. As a result, it was found that the haze value increased and the gloss value decreased as the arithmetic mean height increased. The tendencies for the total light transmittance to decrease and the haze to increase both differed between specimens shot blasted on either single or both sides. Moreover, it was shown that measurement points from either the blasted surface or the unprocessed surface were unlikely to affect haze but that both were likely to affect glossiness due to reflection. Thus, we showed that varying the measurement direction of the processed surface could change the haze value without changing the glossiness.

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  • Hideto MINAMI, Wei LI, Toyoko SUZUKI
    2019 Volume 92 Issue 10 Pages 299-303
    Published: October 20, 2019
    Released: November 02, 2019

    A facile and novel approach of preparing monodisperse polystyrene (PS) particles having a “cylindrical” shape was discovered. The proposed synthetic method involved dispersion polymerization of the spherical PS particles stirred in a polyvinylpyrrolidone (PVP) aqueous solution for several hours using a magnetic stirrer. In the presence of PVP, the spherical PS particles deformed into cylindrical shapes following stirring; however, the particles did not deform in the absence of PVP. The deformation rate of the particles was affected by the molecular weight of dissolved PVP. This stirring method is not only highly efficient and provides high yield, but is also applicable to other materials such as polymethyl methacrylate (PMMA). Moreover, cylindrical polystyrene particles were applied as a particulate stabilizer to prepare a Pickering emulsion of decane (oil)/water. Unlike the spherical particles that are typically used in Pickering emulsions, the cylindrical particles enhanced the emulsion’s stability (up to 1 year). Furthermore, the cylindrical particulate stabilizer enabled a stable emulsion across a wide range of pH. Notably, unique adsorption behavior of the cylindrical particles on an oil droplet was observed, in which the cylindrical particles connected head to head to form a network that acted as a cage around the oil droplet.

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Serial Lecture