Compositions: coating or plastic – Materials or ingredients – Pigment – filler – or aggregate compositions – e.g. – stone,...
Reexamination Certificate
2002-06-11
2003-07-22
Green, Anthony J. (Department: 1755)
Compositions: coating or plastic
Materials or ingredients
Pigment, filler, or aggregate compositions, e.g., stone,...
C106S413000, C106S416000, C106S417000, C106S426000, C106S429000, C106S465000, C106S471000, C106S487000, C106S490000, C106S493000, C106S494000, C106S495000, C106S496000, C106S497000, C106S498000, C106S499000, C524S261000
Reexamination Certificate
active
06596071
ABSTRACT:
BACKGROUND OF THE INVENTION
The present invention relates to organic and inorganic composite pigments, a paint using the organic and inorganic composite pigments, and a resin composition using the organic and inorganic composite pigments. More particularly, the present invention relates to organic and inorganic composite pigments not only being lessened in amount of organic pigments desorbed from the surface of the white inorganic particles, but also exhibiting an excellent light resistance owing to good ultraviolet absorbing property thereof, a paint using such organic and inorganic composite pigments, and a resin composition using such organic and inorganic composite pigments.
As well known in the art, inorganic pigments and organic pigments have been used as color pigments for resins, paints, printing inks or the like according to the applications.
In general, it is known that the inorganic pigments have an excellent light resistance, but are have a low tinting strength and fail to show a clear hue. There have been known some inorganic pigments capable of exhibiting a clear hue. However, many of these inorganic pigments having a clear hue contain as constituents thereof, harmful metals such as lead, mercury, cadmium, chromium or the like. Therefore, it has been strongly required to provide alternate harmless pigments exhibiting a more clear hue instead of such inorganic pigments from the standpoints of hygiene, safety and environmental protection.
On the other hand, it is known that the organic pigments exhibit a clear hue, but have low hiding power and are deteriorated in light resistance.
In addition, various pigments as described above have been frequently used in outdoor applications and, therefore, required to maintain a good hue thereof for a long period of time. Also, it is necessary that the pigments have a good light resistance, in particular, are free from discoloration by ultraviolet light.
Thus, it has been required to provide pigments exhibiting not only a clear hue, but also excellent tinting strength and light resistance.
Hitherto, in order to obtain pigments having excellent properties required for color pigments, it has been attempted to use the inorganic pigments in combination with the organic pigments. For example, there have been proposed a method of co-precipitating chrome yellow and phthalocyanine blue together; a method of adhering the organic pigments onto the surface of the inorganic pigments; or the like (Japanese Patent Application Laid-Open (KOKAI) Nos. 4-132770 (1992) and 11-181329 (1999), etc.). Further, there have been known particles exhibiting an excellent ultraviolet-absorbing property, which contain ultraviolet light-absorbing compounds (Japanese Patent Application Laid-Open (KOKAI) Nos. 11-222421 (1999) and 2000-80021, etc.).
At present, it has been strongly required to provide composite pigments not only being lessened in amount of organic pigments desorbed from the surface of white inorganic particles, but also exhibiting an excellent light resistance. However, conventional composite pigments have failed to satisfy these properties.
That is, in the case of the composite pigments obtained by co-precipitating chrome yellow and phthalocyanine blue together, the chrome yellow used therein has a toxicity, and a paint obtained using such composite pigments is deteriorated in storage stability owing to the co-precipitation production method. Further, a coating film obtained from the paint tends to suffer from color-floating in some cases.
In the method described in Japanese Patent Application Laid-Open (KOKAI) No. 4-132770 (1992), since the organic pigments are precipitated in the presence of the inorganic pigments, the adhesion of the organic pigments onto the inorganic pigments is insufficient.
In the method described in Japanese Patent Application Laid-Open (KOKAI) No. 11-181329 (1999), after the organic pigments are added to a solution prepared by dissolving organopolysiloxane in cyclic silicone solution, so as to be subjected to fine particle treatment, the obtained particles are adhered to high-oil absorption inorganic pigments, and then the cyclic silicone is volatilized therefrom. Therefore, the adhesion of the organic pigments onto the inorganic pigments is insufficient.
In Japanese Patent Application Laid-Open (KOKAI) No. 11-222421 (1999), it is described that an ultraviolet light-absorbing compound is bonded onto the surface of inorganic particles through a coupling agent. The object of the invention of this KOKAI is to provide an ultraviolet light-protecting agent having a good transparency, but not to provide composite pigments having a clear hue.
In Japanese Patent Application Laid-Open (KOKAI) No. 2000-80021, it is described that a liquid organic ultraviolet light-absorbing compound is coated onto inorganic pigments through an organic high-molecular compound. However, since the pigments are obtained by coat-treating inorganic particles, nylon powder or spherical silicone resin particles with the liquid organic ultraviolet light-absorbing compound, the obtained particles fail to show a clear hue.
Further, in Japanese Patent Application Laid-Open (KOKAI) No. 11-323174 (1999), there are described iron-based black composite particles comprising black iron oxide particles or black iron oxide hydroxide particles as core particles; a coating formed on the surface of the core particle, comprising organosilane compounds obtainable from alkoxysilanes; and a carbon black coat formed on the coating layer composed of the organosilane compounds. However, this KOKAI is directed to the technique for fixedly adhering carbon black onto the core particle and, therefore, the technical sphere of this KOKAI is quite different from that for obtaining pigments having a high chroma and exhibiting a more excellent light resistance, in particular, being free from dicolorationby ultraviolet light.
As a result of the present inventors' earnest studies for solving the above problems, it has been found that by forming an organic pigment coat onto the surface of white inorganic particles through a coating composed of organosilane compounds obtainable from alkoxysilanes, or polysiloxanes, and allowing an ultraviolet light-absorbing agent to exist in any portion from the surface of the white inorganic particle to the surface of the organic pigment coat (including such a case where the ultraviolet light-absorbing agent is adhered onto the organic pigment coat), the obtained organic and inorganic composite particles not only exhibit an excellent clear hue and an excellent light resistance, but also contain no harmful elements. The present invention has been attained on the basis of the above finding.
SUMMARY OF THE INVENTION
An object of the present invention is to provide organic and inorganic composite pigments being lessened in amount of organic pigments desorbed from the surface of the white inorganic particles, exhibiting an excellent clear hue and an excellent light resistance, and containing no harmful elements.
To accomplish with the aim, in a first aspect of the present invention, there are provided organic and inorganic composite pigments having an average particle diameter of 0.01 to 10.0 &mgr;m, comprising:
white inorganic particles;
a coating formed on surface of said white inorganic particle, comprising organosilane compounds obtainable from alkoxysilanes, or polysiloxanes;
an organic pigment coat formed on said coating in an amount of 1 to 200 parts by weight based on 100 parts by weight of the white inorganic particles; and
an ultraviolet light-absorbing agent existing in at least a part of any portion from the surface of said white inorganic particle to surface of said organic pigment coat.
In a second aspect of the present invention, there are provided organic and inorganic composite pigments having an average particle diameter of 0.01 to 10.0 &mgr;m, comprising:
white inorganic particles;
a coating layer formed on surface of said white inorganic particle, comprising at least one compound selected from the group consisting of hydroxides of
Hayashi Kazuyuki
Iwasaki Keisuke
Morii Hiroko
Ohsugi Mineko
Shimohata Yusuke
Green Anthony J.
Toda Kogyo Corporation
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