Effect pigments based on Al.sub.2O.sub.3 flakes with high weather resistance and less photoactivity and to their use thereof in paints, industrial coatings, automotive coatings, printing inks, cosmetic formulations. The effect pigments have a ratio of the amount by weight of Al.sub.2O.sub.3 of the Al.sub.2O.sub.3 flake and the amount by weight of the metal oxide(s) of the coating layer(s) in the range of from 27:73 to 83:17 based on the total weight of the effect pigment.

A pigment, including a flake including a metal core having a first surface and a second surface, a first dielectric layer interfacing with a first surface of the metal core, and a second dielectric layer interfacing with a second surface of the metal core; a first inorganic layer encapsulating the flake; and an organic layer encapsulating the first organic layer is disclosed. A colorant composition including the pigment is also disclosed. A method of making the pigment, and a method of making a colorant composition are also disclosed.

This invention involves a coated flaky metal effect pigment comprising a metal effect flake as substrate coated by the following consecutive coating sequences: a) optionally a discontinuous or a continuous layer of Mo-oxide, b1) an inorganic metal oxide layer comprising mainly SiO.sub.2, c1) a hybrid layer comprising SiO.sub.2 modified by a diphenyl silane, a phenylsilane or mixtures thereof or c2) a hybrid layer comprising SiO.sub.2 modified by a diphenyl silane, a phenylsilane or mixtures thereof, b2) an inorganic metal oxide layer comprising mainly SiO.sub.2, and d) optionally a further top-coat of organofunctional silanes, titanates, aluminates or zirconates.

There is disclosed a functional lamellar particle including an unconverted portion of the lamellar particle, wherein the unconverted portion includes a first metal, a converted portion of the lamellar particle disposed external to a surface of the unconverted portion, wherein the converted portion includes a chemical compound of the first metal; and a functional coating disposed external to a surface of the converted portion.

There is disclosed a lamellar particle including an unconverted portion of the lamellar particle, wherein the unconverted portion includes a first metal, a converted portion of the lamellar particle disposed radially outward of at least one of a surface of the unconverted portion, wherein the converted portion includes a chemical compound of the first metal.

The present invention relates to interference pigments based on multicoated flake-form substrates which have on the surface of the substrate a layer sequence comprising (A0) optionally a high-refractive-index coating consisting of a layer of TiO.sub.2, (A) a high-refractive-index coating consisting of a mixture of TiO.sub.2 and Fe.sub.2O.sub.3, which may optionally be doped with one or more further oxides, (B) a high-refractive-index layer consisting of SnO.sub.2, (C) a high-refractive-index coating which absorbs in the visible wavelength region, and optionally (D) an outer protective layer, and to the use thereof, in particular in paints, coatings, industrial coatings, automobile paints, automotive refinish paints, coil coating, powder coatings, printing inks, plastics, pigment pastes, pigment preparations and in dry preparations, such as, for example, granules.

The invention relates to pigments with a non-metallic substrate, wherein the pigments have at least one barrier layer that selectively absorbs light and/or electrons and at least one photocatalytically active layer, wherein the at least one barrier layer is arranged between the non-metallic substrate and the at least one photocatalytically active layer. The invention furthermore relates to a method for producing the pigments and to a coating agent.

Disclosed herein is an effect pigment having a layer stack which comprises a highly reflective metallic flake having a first major interface and opposed to this first interface a second major interface, and at least one side surface and directly adjacent on one or of both of these major interfaces a layer of a semiconducting material having an average atomic composition of: a) Si.sub.(1-x)Sn.sub.x, wherein 0<x<0.90 or b) Ge.sub.(1-y)Sn.sub.y, wherein 0<y0.80 or c) Si.sub.(1-m-n)Ge.sub.mSn.sub.n, wherein 0<m<1.00, 0<n<1.00 and with the proviso that m+n<1.00.

The present invention relates to a process for preparing a coloured effect pigment, comprising the steps of (a) preparing in an aqueous coating medium at least one layer of a hydroxyl-containing metal oxide on a substrate, thereby obtaining in the aqueous coating medium a first coloured pigment material CPM1 comprising the substrate coated with the hydroxyl-containing metal oxide, wherein the substrate is made of aluminium or aluminium alloy which optionally comprises at least one passivating layer, and wherein the hydroxyl-containing metal oxide is a hydroxyl-containing iron oxide or a hydroxyl-containing titanium oxide or a mixture thereof, (b) providing the first coloured pigment material CPM1 in a liquid post-treatment medium comprising one or more high boiling organic liquids, and (c) heating the liquid post-treatment medium to a temperature of at least 90 C. so as to convert the first coloured pigment material CPM1 to a second coloured pigment material CPM2.

The present invention relates to weather-resistant pearlescent pigment, comprising a coated or uncoated platelet-shaped substrate which is selected from the group consisting of synthetic mica platelets, glass platelets, SiO.sub.2 platelets, Al.sub.2O.sub.3 platelets, synthetic boehmite platelets, BiOCl platelets and mixtures thereof, a chromophoric coating with at least one highly refractive metal oxide, and a top layer, wherein the top layer comprises the following layer sequence:
a) a first layer made of tin oxide and/or tin hydroxide and/or hydrated tin oxide, b) a second cerium-containing layer which comprises cerium oxide and/or cerium hydroxide and/or hydrated cerium oxide, c) an organic-chemical coating applied to the cerium-containing layer which contains oligomeric silanes or consists of them, wherein the oligomeric silanes have one or more amino groups and the oligomeric silanes are chemically bonded with the cerium-containing layer. The invention further relates to a process for the production and use of these pearlescent pigments.