Magnetic pigments containing a transparent flaky homogeneously composed substrate having two parallel major surfaces and a coating containing maghemite, a process for the production of said pigments as well as their use.

A colored metallic pigment of the present invention contains a metallic pigment, a coloring pigment, a first compound and a second compound. The coloring pigment adheres to the surface of the metallic pigment in the coexistence of the first compound and the second compound, the first compound is a compound having two or more carboxyl groups, and the second compound is a compound having one or more amino groups.

Carbon black-containing composite particles of the present invention each include a silicon oxide and carbon black particles dispersed inside the silicon oxide. When a coating film containing the carbon black-containing composite particles dispersed in a transparent matrix, having a concentration of the carbon black particles of 1 mass %, and having a thickness of 25 m to 40 m is formed on a hiding-chart specified in JIS (Japanese Industrial Standards) K 5600-4-1: 1999, a difference L.sub.W*L.sub.B* obtained by subtracting lightness L.sub.B* of the coating film formed on a black part of the hiding-chart from lightness L.sub.W* of the coating film formed on a white part of the hiding-chart is 30 or less. Thus carbon black-containing composite particles advantageous in exhibiting a good hiding property and reducing an undertone can be provided.

A nano-composite structure. A synthetic nano-composite is described having a first component including a fibrous structured amorphous silica structure, and a second component including a precipitated calcium carbonate structure developed by pressure carbonation. The nano-composite may be useful for fillers in paints and coatings. Also, the nano-composite may be useful in coatings used in the manufacture of paper products.

There are very few violet or pink colored commercial pigments that display high heat stability, resistance to acidic conditions, or good lightfastness. This technology results in pigments that fall into the above color space, but display improved chemical and weathering stability. The pigments based of this technology have the molar ratio (A.sub.2O).sub.x(BO).sub.y(C.sub.2O.sub.5).sub.z(DO.sub.3).sub.w(EO.sub.2).sub.v, where 2x+y+2z+w+v100. Where A is Li or Li with one or more of Cu, Na, or K, where B is Co or Co with one or more of Ca, Cu, Fe, Mg, Mn, Ni, Sn, or Zn, where C is Nb, Sb, or combination thereof, where D is Mo, W or combination thereof, where E is Sn, Ti, Zr, or combination thereof. The above formulation may be modified with a dopant addition of Al, B, Ba, Bi, Ca, Ce, Cr, La, P, Pr, Si, Sr, Ta, V, or Y where the dopant concentration represents 5 atomic % or less of the total number of moles of components A+B+C+D+E.

The present invention relates to pearlescent pigments, to a process of manufacturing such pearlescent pigments based on a wet oxidation step as well as to the use of such pearlescent pigments.

A colored metallic pigment of the present invention contains a metallic pigment, a coloring pigment, a first compound and a second compound. The coloring pigment adheres to the surface of the metallic pigment in the coexistence of the first compound and the second compound, the first compound is a compound having two or more carboxyl groups, and the second compound is a compound having one or more amino groups.

The use of an effect pigment (a) comprising an aluminum-based substrate and an iron oxide coating having a red 1.sup.st order interference color in combination with a colored absorption pigment (b) for producing a coating having enhanced coloristic properties, in particular enhanced chroma, lightness and hiding power, is provided. The pigment combination of (a) and (b) is suitable for coloring plastics, a fiber, a film and a coating composition such as a paint, a printing ink, a varnish or a powder coating, preferably an automotive, an architectural or an industrial coating composition.

A bright pigment according to the present invention includes: a glass flake; a titanium oxide layer formed over the glass flake; and fine gold particles deposited on the titanium oxide layer or placed between the glass flake and the titanium oxide layer. The titanium oxide layer has a thickness of 150 nm or more, and a reflected color of the bright pigment is a blue to green color represented by a C* value of 15 or more and a h value of 150 to 300 in a L*C*h color system.

The subject of the invention is a method for the production of pigment from filtration sludges containing manganese and iron and phosphates, characterised in that the filter sludge is sieved on a vibrating sieve, then the suspension is concentrated and dried to a water content below 8% w/w, after which the material is subjected to thermal treatment at a temperature in the range of 500-1200? C. for a period of 6-12 hours, and the obtained sinter is fragmented and optionally dried to a moisture level of 5%. The invention also relates to using the pigment produced by the foregoing method colouring construction ceramic products or as a colouring additive to the mass from which construction products are formed or as a colouring additive for concrete.