Aqueous powder coat dispersions, process for their preparation and their use
AssigneeE. I. Du Pont de Nemours and Company
InventorsKarl-Friedrich Doessel, Oliver Reis, Volker Rekowski
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Abstract
Improved aqueous powder coat dispersion, comprising (a) a powder coating dispersed in (b) an aqueous phase, wherein the aqueous phase contains a silica compound selected from the group consisting of (i) 0.2 to 2% by weight, based on the weight of the powder coating, of finely divided silicic acid with large BET-surface; (ii) 0.1 to 1.5% by weight, based on the weight of the powder coating, of layered silicates; and (iii) combinations thereof, exhibit improved sedimentation properties and provide coatings with improved sag characteristics.
Claims10
An aqueous powder clear coat dispersion comprising a powder clear coating dispersed in an aqueous phase, wherein the powder clear coat dispersion has a solid content of 20 to 60% by weight of particles having an average particle diameter (d50) of 0.1 to 10 μm, a binder selected from the group consisting of polyester resins, (meth)acrylic copolymers and polyurethane resins, and wherein the aqueous phase contains a silica compound selected from the group consisting of:
- (a) 0.2 to 2% by weight, based on the weight of the powder clear coating, of finely divided hydrophilic silicic acid with large BET-surface;
- (b) 0.1 to 1.5% by weight, based n the weight of the powder clear coating, of layered silicates;
- and
- (c) combinations thereof.
A process for the preparation of an aqueous powder clear coat dispersion comprising the steps of:
- (a) incorporating a powder clear coating into an aqueous composition;
- and
- (b) incorporating a silica compound into said aqueous composition, wherein said silica compound is selected from the group consisting of:
- (i) finely divided hydrophilic silicic acid with large BET-surface;
- (ii) layered silicates;
- and
- (iii) combinations thereof.
Dependencies are inferred from the claim text.