Compositions: coating or plastic – Materials or ingredients – Pigment – filler – or aggregate compositions – e.g. – stone,...
Patent
1994-03-01
1995-10-10
Bell, Mark L.
Compositions: coating or plastic
Materials or ingredients
Pigment, filler, or aggregate compositions, e.g., stone,...
106425, 106426, 106428, 106442, 524449, C04B 1420
Patent
active
054567491
DESCRIPTION:
BRIEF SUMMARY
FIELD OF THE INVENTION
The present invention relates to a pearly luster pigment with an anti-discoloring property and an excellent dispersing property, and to a method of preparing the same. The pigment of the present invention can be used as a pigment additive in preparation of plastic articles, inks, coating compositions and decorative boards.
BACKGROUND OF THE INVENTION
Recently, a titanium oxide resp. titanium oxide hydrate coated mica pigment as used as a colorant for resins has been found to have a problem of causing discoloration (especially, yellowing) of resins with the lapse of time so that the resulting resins lose their original color. This is due to the addition of additives of a hindered amine light stabilizer (HALS), a phenolic antioxidant such as BHT, a flame retarder and an ultraviolet stabilizer to resins, to the titanium oxide-coated mica. In this connection, it is known that where titanium dioxide resp. oxide hydrate is in a resin, the titanium dioxide is catalytically activated due to light or heat energy as imparted thereto to thereby promote the interaction of the additives, or that the titanium dioxide directly reacts with the additives to cause discoloration of so-called yellowing phenomenon. (S. Okazaki, Colorants, 6, 333-341 (1987); M. Seino, Titanium Oxides (published by Gihodo Publishing Co. ), pp. 103-106; I. Jagnandan, H. Daun, T. J. Ambrosis & S. G. Gilbert, Journal of Pharmaceutical Science, 68 (7) 916 (1979); N. S. Allen, D. J. Bullen and J. F. Keller, Journal of Materials Science, 12, 1320 (1977)).
Due to the phenomenon, containers, decorative boards and other articles to be manufactured from the resins containing the materials would discolor with the lapse of time, after stored, to eventually lose their original colors.
As a method of inhibiting the catalytic activity of titanium dioxide in order to evade the phenomenon, in general, there has been provided a technique of stabilizing titanium dioxide by doping one or more of chromium compounds, silicon compounds, aluminum compounds, zinc compounds, phosphoric acid compounds and zirconium compounds thereinto or by coating one or more of them thereover.
However, if such a surface-coating method is applied to a pearly luster pigment, in general, it would result in loss of the intrinsic luster of the pearly pigment since the amount of the coat is relatively large, i.e. from 5 to 20% by weight to the weight of the pigment as coated therewith. Japanese Patent Application Laid-Open No. 1-225669 has disclosed an organic acid-coated anti-yellowing titanium dioxide pigment. In the disclosed case, since the surface-treating agent is an organic material, the coated pigment may still have its pearly luster. However, with the lapse of time, the storage stability of the coated pigment becomes unsatisfactory.
SUMMARY OF THE INVENTION
The object of the present invention is to overcome the problems in the prior art techniques. Therefore, the present invention provides a novel pearly luster pigment having the following characteristics (1 ) to (3) and also a method of preparing the same.
(1) It has an excellent anti-discoloring property for a long period of time.
(2) It hardly coagulates and has a good dispersing property.
(3) It does not lose its pearly luster.
Specifically, the present invention provides an anti-discoloring pearly luster pigment on the basis of mica particles coated with titanium dioxide and/or titanium oxide hydrate wherein: coated mica particles are coated with from 1 to 7 parts by weight, to 100 parts by weight of the titanium dioxide and/or titanium oxide hydrate coated mica particles, of a silicon oxide and/or silicon oxide hydrate; parts by weight, to 100 parts by weight of the titanium dioxide and/or titanium oxide hydrate coated mica particles, of an aluminum oxide and/or aluminum oxide hydrate; and 0.5 to 3 pans by weight, to 100 pans by weight of the titanium dioxide and/or titanium oxide hydrate coated mica particles, of a zinc oxide and/or zinc oxide hydrate.
The present invention also provides a method
REFERENCES:
patent: 3087828 (1963-04-01), Linton et al.
patent: 3087829 (1963-04-01), Linton et al.
patent: 4537636 (1985-08-01), Bernhard et al.
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patent: 5266107 (1993-11-01), Hoffman
Abstract of JP 1,158,077. Derwent AN 89-223232, Nov. 1987.
Verified Translation of PCT/EP92/01295, Jul., 1992.
Chemical Abstracts, vol. 107; 107:79502z of JP 60(6), 333-341, Okazaki, Shikizai Kyokaishi, 1987 no month.
Jagnandan et al., "Isolation and Identification of 3,3',5,5'-Tetra . . . ", J. of Pharm. Sci. vol. 68, No. 7, Jul. 1979, pp. 916-917.
J. Matr. Sci., Jul. 1977 pp. 320-324 (12):7, Allen et al. "Photo-oxidation of commercial PE-Cont'g TiO.sub.2 (rutile)/antioxidant systems".
Iwasa Kazuhisa
Nitta Katsuhisa
Noguchi Tamio
Bell Mark L.
Hertzog Scott L.
Merck Patent Gesellschaft mit beschrankter Haftung
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