Journal of the Japan Society of Colour Material
Online ISSN : 1883-2199
Print ISSN : 0010-180X
ISSN-L : 0010-180X
Volume 75 , Issue 5
Showing 1-7 articles out of 7 articles from the selected issue
  • Kanji MORI, Kazuo OKAMOTO, Kazuyuki TACHI
    2002 Volume 75 Issue 5 Pages 209-213
    Published: May 20, 2002
    Released: November 20, 2012
    JOURNALS FREE ACCESS
    A new treatment for a rapid weatherability test method for coatings has been studied. Nine alkyd-melamine coatings films containing TiO2 pigment were subjected to UV irradiation of 97 W/m2 (300-400 nm) in aqueous solutions of 3.0-wt% hydrogen peroxide, 5.0-wt% sodium hypochlorite and 1.0-wt% sodium peroxocarbonate for 50 h at 40°C, and gloss and surface morphology were examined. Four coatings were formulated from different resins with a TiO2 pigment, the other five coatings were formulated from different organic pigments with a TiO2 pigment and a resin. These films were also outdoor-weathered in Okinawa for 2 years.
    Gloss was decreased with treatment time. SEM observation showed that the gloss loss resulted from formation of small pits by resin loss around TiO2 pigment. The same results were obtained in all cases of oxidizing agents and coatings. The formation of pits is observed in every outdoor-weathered coatings film. Thus our treatment is a rapid method to reproduce outdoor degradation. The resin loss around TiO2 pigment is supposed to be caused by photocatalytic oxidation enhanced by oxidizing agents.
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  • Taku KATO, Keiichi SAKAMOTO
    2002 Volume 75 Issue 5 Pages 214-220
    Published: May 20, 2002
    Released: November 20, 2012
    JOURNALS FREE ACCESS
    Unsymmetrical zinc bis (didecylbenzo) -3, 4-dipyridoporphyrazine having two nonperipheral didecyl-benzenoid rings and two pyridinoido rings was synthesized from a mixture of same amount of 3, 6-didecylphthalonitrile and 3, 4-dicyanopyridine in the presence of zinc chloride. Zinc bis (didecylbenzo) -3, 4-dipyridoporphyrazine was obtained as a mixtures of several position isomers, which was separated into four fractions and the components were characterised with 400 MHz proton nuclear magnetic resonance, visible and fluorescence spectroscopies, and cyclic voltammetry. The visible spectroscopy showed correlation between splitting of Q-band and molecular structure of each position isomer.
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  • Toyohiko YOSHIDA
    2002 Volume 75 Issue 5 Pages 221-226
    Published: May 20, 2002
    Released: November 20, 2012
    JOURNALS FREE ACCESS
    The changes of specular gloss of coatings by exposure tests obey well to a logistic equation.
    When a function of gloss (y), expressed as (y) as f (y) =ln {(A-y) / (y-B)},
    was plotted against exposure time, a straight line was obtained, where A and B are higher and lower limits of gloss, respectively.
    The coefficient of determination for the regression of this plot was as high as over 0.9. The calculated gloss using the coefficients in the regression equation matched very well to those observed. The sample data used in this investigation were the gloss of air dried urethane resin enamels exposed at Choshi and Miyakojima. Fairly satisfactory gloss was estimated when A and B were assumed to be 100 and 0, respectively, except for a few samples that had high residual gloss after the exposure.
    The ratio of exposure periods to reach a same gloss at different exposure sites or conditions of exposures differed depending on the levels of gloss. We should pay attention that the ratio of the velocities of deterioration differs depending on the varieties of coatings, the compatibility or affinity of the components, properties associated with deterioration, and the levels of deterioration.
    Because the logistic equation has a symmetrical shape, detailed observation of the first half enables quite correct estimation of the latter half.
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  • Kiroku ICHIKAWA
    2002 Volume 75 Issue 5 Pages 227-231
    Published: May 20, 2002
    Released: November 20, 2012
    JOURNALS FREE ACCESS
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  • Gin-ya ADACHI, Toshiyuki MASUI
    2002 Volume 75 Issue 5 Pages 232-237
    Published: May 20, 2002
    Released: November 20, 2012
    JOURNALS FREE ACCESS
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  • Takefusa NAKAMURA
    2002 Volume 75 Issue 5 Pages 238-242
    Published: May 20, 2002
    Released: November 20, 2012
    JOURNALS FREE ACCESS
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  • Akira KIJIMA
    2002 Volume 75 Issue 5 Pages 243-248
    Published: May 20, 2002
    Released: November 20, 2012
    JOURNALS FREE ACCESS
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