Huels Aktiengesellschaft

Degussa Aktiengesellschaft

Degussa-huels Aktiengesellschaft

Creanova Spezialchemie Gmbh

Dirk Reichel

Klaus Janischewski

Hartwig Lange

Rainer Lomoelder

Friedrich Plogmann

A stable and high-solids aqueous dispersion of blocked isocyanates, containing auxiliary solvent, is prepared by (1) preparing a solution of a polyisocyanate mixture of from 20-70% by weight of a blocked, hydrophilically modified polyisocyanate (A) and from 30-80% by weight of a blocked, hydrophobic polyisocyanate (B) in an auxiliary solvent (G) and (2) adding water to this solution, with intensive mixing, in an amount which is such as to give a two-phase system comprising a disperse polyisocyanate phase and a continuous, aqueous phase containing auxiliary solvent. In a preferred embodiment of the invention dispersions are prepared which are virtually free from auxiliary solvent, by first adding a portion of water to the solution (1), substantially removing the auxiliary solvent with intensive mixing and then adding a second portion of water with intensive mixing to the mixture comprising the polyisocyanates (A) and (B) and the first portion of water.

Stable and high solids aqueous dispersions of blocked polyisocyanates

An aqueous 2-component PU coating composition essentially comprising: A) an aqueous dispersion of at least one polyol component, B) a polyisocyanate component based on 2-methylpentane 1,5-diisocyanate, the proportions of A and B corresponding to an OH/NCO equivalents ratio of from 1:0.5 to 1:5.

Aqueous two-component polyurethane coating compositions based on 2-methylpentane-1,5-diisocyanate

A composition containing an unblocked monomeric diisocyanate finely dispersed an aqueous dispersion of at least one organic polyhydroxy compound. The composition may be used to prepare aqueously disperse two component polyurethane coatings where the diisocyanate functions as a curing agent and the polyhydroxy compound serves as a binder agent. In the composition, the ratio of hydroxyl groups in the polyhydroxy compound to the isocyanate groups in the diisocyanate is 0 5:1 to 5:1. The composition may be used to apply polyurethane coatings to substrates.

Aqueous two component polyurethane coatings, preparation thereof and use

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Dorsten, Germany

Dirk Reichel