Journal of the Japan Society of Colour Material
Online ISSN : 1883-2199
Print ISSN : 0010-180X
ISSN-L : 0010-180X
Volume 93 , Issue 1
Showing 1-4 articles out of 4 articles from the selected issue
Original Research Paper
  • Taishu KUMAGAI, Maki SAKAMOTO, Yoshimune NONOMURA
    2020 Volume 93 Issue 1 Pages 2-8
    Published: January 20, 2020
    Released: January 28, 2020

    In order to clarify the mechanism of nukumori feel under sliding motion, ten kinds of materials were selected for sensory evaluation based on tactile dimension and analysis of the relationship between their physical properties and tactile factors. We found that not only the warm feel but also the soft feel is important for recognition of nukumori feel. The warm feel is perceived with the decrease of initial heat flux maximum value (q-max) because a large surface roughness increases thermal resistance. In addition, the soft feel was recognized when the Young's modulus and the friction parameter ks, which indicates the contribution of the elastic term of the frictional force at the start of the sliding process, were small. This shows that the soft feel was perceived by large strain in the longitudinal direction of the materials and the slow increase of the frictional force from start of the sliding to the maximum static friction.

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  • Takuma OTANI, Hiroaki KOUZAI
    2020 Volume 93 Issue 1 Pages 9-13
    Published: January 20, 2020
    Released: January 28, 2020

    Polyurethane CU-LTI was synthesized by curcumin and lysine triisocyanate. The structural analysis of the obtained CU-LTI was measured by FT-IR spectrum. Peaks attributed to N-H groups and C=O groups were confirmed. From the ultraviolet-visible absorption spectrum of CU-LTI, the absorption peak at 450 nm was confirmed. In the fluorescence spectrum of CU-LTI, an emission peak at 520 nm was confirmed. From the result of TG measurement, the starting temperature of thermogravimetric loss of polyurethane was about 200℃. The glass transition temperature of CU-LTI was 70℃. The stress-strain curve shows that polyurethane is relatively soft and stretchable.

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Original Technical Paper
  • Yuji WAKABAYASHI, Makiko YONEHARA, Hidetoshi YAMABE, Shun YOSHIDA, Tak ...
    2020 Volume 93 Issue 1 Pages 14-22
    Published: January 20, 2020
    Released: January 28, 2020

    A method for evaluating the correlation between visual textures, i.e., convex-concave shape (surface texture), haze, gloss, brightness, of the specimen surface was proposed using self-organizing maps known as the neural network model of machine learning. It takes a lot of time and effort to weight the correlations in detail because there are many visual factors. Therefore, a simple comparison was verified using the similarity ratio of weighting pattern which appears in the output layer of self-organizing maps. First, the efficacy of this method was confirmed using the functions such as Y=X and Y=sin(X). Additionally, this method was applied to the visual texture evaluation of a transparent acrylic resin which had been shot blasted. As a result, it was shown that several surface texture parameters affected the haze, gloss and brightness of the specimen and that these parameters were maximum height Sz, maximum peak height Sp, root mean square slope Sdq and aspect ratio of texture Str.

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  • Masato YAMAMURA
    2020 Volume 93 Issue 1 Pages 23-27
    Published: January 20, 2020
    Released: January 28, 2020

    Liquid thin film coating is one of the common fundamental technologies that covers a wide range of advanced material processes. To achieve uniform coatings of various types of soft matter, i.e., suspensions, colloids, gels, etc., at high speeds over larger areas, we need a deeper understanding of physical links between the formation mechanisms of undesirable defects and rheological properties of the coating liquids. This article focuses on the slot-die coating technology of particle suspensions and provides a brief but comprehensive overview of liquid formulations that are less prone to coating/drying defects thereby helping to achieve faster production rates.

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