Merck Patent Gesellschaft MIT Beschrankter Haftung

Merck Patent Gesellschaft MIT Beschraenkter Haftung

Horst Bernhard

Reiner Esselborn

Jorg Ohngemach

Otto Stahlecker

Kurt Marquard

Wilhelm Baumer

Reiner Hesse

Fritz Zureda

Alfred Stein

Horst Russmann

Nacreous pigments having improved light fastness are based on mica platelets coated with titanium dioxide and, optionally other additional metal oxides. These pigments carry an additional thin manganese oxide layer. The pigments are prepared in a process wherein mica is coated in aqueous suspension with one or more titanium dioxide hydrate layers and, optionally, with further metal oxide layers, mixed with the titanium dioxide hydrate or separately therefrom, and then is washed, dried and calcined. The process further comprises precipitating an additional layer of manganese hydroxide onto the base pigment, either directly after coating with the titanium dioxide hydrate and/or metal oxide layers or after the calcination thereof. The flakes are the washed, dried and calcined. The new pigment can be used for pigmenting plastics, lacquers, paints and cosmetics, inter alia.

Nacreous pigments having improved light fastness, their preparation and

A process for preparing nacreous pigments having improved gloss properties and based on mica platelets coated with metal oxides comprises suspending mica platelets in a solution containing titanium sulfate, the mica platelets having a coating comprising a homogeneous mixture of titanium dioxide, aluminum oxide and silicon dioxide, and further coating the suspended platelets by slow heating of the suspension.

Process for the preparation of nacreous pigments with improved gloss

Nacreous pigments having improved light fastness are based on mica flakes coated with metal oxides, wherein the metal oxide layer is formed as a homogeneous mixed layer in which, in addition to titanium dioxide, silicon dioxide and iron oxide are also present. To produce these pigments, mica is coated in an aqueous suspension by coprecipitation of a titanium dioxide hydrate, iron hydroxide and silicon dioxide to form a uniform layer. The flakes are then washed, dried and calcined. The pigments can be used for the pigmenting of plastics, lacquers, paints and toiletries.

Nacreous pigments having improved transparency and tinctorial strength and based on mica flakes coated with metal oxides, have a metal oxide layer which is formed as a homogeneous mixed layer in which, in addition to titanium dioxide, there also is present silicon dioxide and aluminum oxide. These can be produced by coating mica in an aqueous suspension with a titanium dioxide hydrate layer and then washing, drying and calcining. Silicon dioxide and aluminum hydroxide are precipitated as a uniform layer together with the titanium dioxide hydrate. The new pigments can be used for pigmenting plastics, lacquers, paints and cosmetics, inter alia.

Nacreous pigments, their preparation and use

A process for rendering nacreous pigments hydrophobic, the pigments being based on mica platelets coated with metal oxides, comprises coating the pigments in aqueous suspension with a chromium (III) or aluminum (III) hydroxide or silicate, and then treating the coated pigments with a solution of a hydrocarbon carboxylic acid having more than four carbon atoms per carboxyl group.

Process for rendering nacreous pigments hydrophobic

Nacreous pigments comprise a mica platelet coated with a first layer of a metal oxide and a second layer of chromium(III) oxide, wherein the chromium oxide layer further contains at least 0.05 mol % of phosphate ion based on the number of moles of chromium ion therein. Because of the phosphate ion, the chromium layer is continuous and essentially crack-free even at larger thicknesses, and contributes to the interference effect. The pigments are particularly useful as lustrous agents in cosmetics.

Green nacreous pigments having calcined Cr oxide and phosphate layer,

Nacreous pigments having a yellow powder color and an improved light-fastness comprise a mica platelet coated with titanium dioxide and on the titanium dioxide layer, a thin layer of calcined chromium oxide and/or chromium phosphate as a protective layer. The pigments are produced by coating mica platelets coated with metal oxides and/or hydroxides, with a thin layer of a sparingly soluble chromium(III) compound and calcining at about 500.degree.-1000.degree. C.

Yellow nacreous pigments having calcined CR oxide and phosphate layer

Colored material-containing pearlescent pigments based on mica flakes coated with metal oxide contain as colored material, a colored aluminum lake which is fixed as a water-insoluble compound on the surface of the pigment particles, the lake being formed from a precipitated aluminum hydroxide layer, wherein the aluminum hydroxide layer forming the colored lake contains 1 to 50% by weight of a compound of the formula ##STR1## wherein X is hydroxy or carboxy, Y is hydrogen or alkyl or alkenyl of 10 to 20 carbon atoms and Z is hydrogen, or alkyl or alkenyl of 10 to 20 carbon atoms, or the grouping ##STR2## said compound having a molecular weight of at least 150 and a solubility in water at a pH of 5-9 of at least 0.05 g/l, and said compound being precipitated onto the flakes together with the aluminum hydroxide layer. A process for the production of these pigments is also provided, as are cosmetics containing them.

Preparation and use of improved pearlescent pigments of high light

Pigmented substantially crack-free casein plastic compositions containing a minor, luster-imparting quantity of coated mica platelets, wherein at least 75% of the pigment particles possess an average platelet size of below 10 .mu.m., a thickness of about 0.1 to 0.7 .mu.m. and a ratio of diameter to thickness of about 10 to 200.

Lustrous pigments for pigmenting casein plastics

Mica flake-based lustrous pigments having a plurality of TiO.sub.2 and SnO.sub.2 layers thereon comprising at least one succession of rutile/SnO.sub.2 /rutile have improved properties, including light and weathering fastness.

Rutile-containing lustrous pigments

Lustrous pigments having a wide range of colors and especially suitable for the cosmetics industry are produced by forming an aluminum lake on a micaceous pigment coated with aluminum hydroxide.

Dyed lustrous pigments

A process for the preparation of carbon black-containing pigments consists essentially of precipitation of a carbon black-containing metal hydroxide or bismuth oxychloride layer on substrate particles in an aqueous suspension containing carbon black particles of particle size of below 1 mn. and washing, drying and optionally calcining the products. Flaky substrates, e.g., mica flakes coated with TiO.sub.2, are preferably employed. Carbon black-containing pigments obtained have carbon black particles incorporated in a metal hydroxide, metal oxide or bismuth oxychloride layer precipitated on the substrate in the presence of the carbon black.

Carbon black-containing pigments and process for their preparation

Lustrous pigments based on mica flakes coated with metal oxides have a very uniform coating layer of tin dioxide, which can contain aluminum oxide, or the hydrates thereof.

Tin-containing lustrous pigments

Blue colored mica flake pigments are provided by coating mica flakes, or mica flakes optionally coated with a uniform metallic oxide layer, with a uniform layer of a low-solubility iron compound convertible into Berlin blue [ferric hexacyanoferrate(II)], and then converting this layer into Berlin blue.

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Schwarzenberg, Austria

Horst Bernhard