Basf Corporation

William H Alford

Charles L Tazzia

Grant E Cooley

Michael J Anchor

Gregory W Drewno

Robert D Schiller

The invention relates to aqueous dispersions and aqueous electrodepositable primers made with the aqueous dispersions of the invention. The aqueous dispersion of the invention requires the use of a polymer (a) comprising one or more water dispersible groups per molecule and one or more functional groups (f), and at least one crosslinking agent (b) comprising one or more blocked functional groups (f) reactive with polymer (a) after unblocking. Crosslinking agent (b) has a Tof from 40 to 70&#xb0; C./105 to 158&#xb0; F. and is a solid at 23.9&#xb0; C./75&#xb0; F. when at 100% by weight solids. Crosslinking agent (b) is melt mixed into acrylic polymer (a) to provide a first dispersion and said first dispersion is emulsified in water to provide an aqueous dispersion. In a preferred embodiment, the aqueous electrodepositable primers comprise at least 50% by weight water and an acrylic polymer (a) having one or more salted sites per molecule.

Aqueous dispersions and aqueous electrodepositable primers

The invention relates to a method for preparing aqueous dispersions, especially electrodepositable aqueous dispersions. The invention requires the use of a polymer (a) comprising one or more water dispersible groups per molecule and one or more functional groups (f), and at least one crosslinking agent (b) comprising one or more blocked functional groups (f) reactive with polymer (a) after unblocking. Crosslinking agent (b) has a Tof from 40 to 70&#xb0; C./105 to 158&#xb0; F. and is a solid at 23.9&#xb0; C./75&#xb0; F. when at 100% by weight solids. Crosslinking agent (b) is mixed into polymer (a) at a temperature at or above the melting temperatures of both polymer (a) and compound (b) but below the temperature at which blocked functional groups (f) unblock. Sufficient water is added to the resulting melt-mixture (ii) to provide an aqueous dispersion.

Method for making an aqueous dispersion

The present invention is directed to a powder coating composition and a method. The method improves the color strength of a cured film of the powder-based coating composition. To produce the powder-based coating composition, the method begins by combining a powder-based binder, specifically a resin and a cross-linking agent, with a pigment and a surfactant to form a mixture. The mixture is then extruded thereby forming an extrudate of the mixture. The extrudate is cooled and then ground to produce the powder-based coating composition from the extrudate of the mixture. Next, the powder-based coating composition is spray applied to a substrate and cured to form the cured film. The surfactant in the mixture improves the color strength of the powder-based coating composition and the cured film so that the amount of pigment included in the mixture can ultimately be reduced. Additionally, certain physical properties of the cured film are not compromised.

Powder-based coating composition, a cured film thereof, and a method of improving a color strength of the cured film

A matte powder coating composition including a first carboxyl-functional polyester resin, a second carboxyl-functional polyester resin, and an epoxide-functional crosslinking agent, where the difference in acid values between the first and second carboxyl-functional polyester resins is from about 200 to about 350 mg KOH/g.

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Livonia, MI, United States of America

William H Alford