Basf Corporation

Grant E Cooley

Charles L Tazzia

William H Alford

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.

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Warren, MI, United States of America

Grant E Cooley