Merck Patent Gesellschaft MIT Beschrankter Haftung

Merck Patent Gesellschaft MIT Beschraenkter Haftung

Herberts Gmbh

Reiner Esselborn

Horst Bernhard

Klaus Ambrosius

Hans D Bruckner

Manfred Kieser

Jorg Ohngemach

Klaus-Dieter Franz

Otto Stahlecker

Klaus D Franz

Wilhelm Baumer

Reiner Hesse

Ralf Emmert

Helmut Plamper

Alfred Stein

Horst Russmann

August Knapp

Fritz Zureda

Manfred Letsch

Hans-Joachim Graetz

The application relates to conductive lamellar pigments in which lamellar substrate is coated with an electrically conductive layer, characterized in that a lamellar metal oxide or a lamellar material coated with one or more metal oxides is present as the lamellar substrate and that an optionally hydrated silicon dioxide layer or a layer of another insoluble silicate is arranged between the metal oxide layer and the conductive layer.

Conductive lamellar pigments

In mica/titanium dioxide pigments reliable rutilization is obtained with small amounts of tin by precipitating tin dioxide directly on the mica and completing this precipitation before the precipitation of titanium dioxide is started.

Process for preparing rutile-coated mica pigments

The invention relates to platelet-shaped pigments of the formula Al.sub.x Fe.sub.2-x O.sub.3-y, wherein x has a value from 0.02 to 0.5 and y has a value from 0.3 to 1.0, which are optionally coated with further oxides.

Platelet-shaped iron oxide pigments

Base lacquers suitable for use in multi-layer lacquerings containing a layer of base lacquer and a layer of clear lacquer on top of this, contain a nacreous pigment based on mica flakes coated with metal oxides, wherein the nacreous pigments have a particle size substantially in the range between 5 and 25 .mu.m. The resultant lacquerings have advantageous properties.

Lacquering process using nacreous pigments

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 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

Nacreous pigments which have improved stability to weathering and are based on mica flakes coated with metal oxides, are provided with a stabilizing, chromium-containing second coating which comprises a combination of metal salts. To form the second layer, iron and/or manganese are deposited on the starting pigments in the form of the hydroxide, carbonate or phosphate and chromium is deposited on the starting pigments in the form of the hydroxide, carbonate or phosphate or as methacrylato-chromium chloride. These are prepared by adding iron and/or manganese and chromium, in the form of salt solutions and at a pH of 2 to 8, to an aqueous suspension of a mica flake pigment coated with metal oxides, precipitating them on the mica flake pigments, and separating off these pigments and drying them.

Nacreous pigments

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

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.

Growing community of inventors

Darmstadt, Germany

Reiner Esselborn