Electrocoating composition
AssigneeAxalta Coating Systems IP Co., LLC
InventorsKonstantinos MARKOU, Nevzat ÖZTÜRK, Thomas HUESMANN
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Abstract
Aqueous cathodic electrocoating compositions, methods for preparing aqueous cathodic electrocoating compositions, and methods for electrodepositing coatings from aqueous cathodic electrocoating compositions are provided. An aqueous cathodic electrocoating composition having a binder resin and a crosslinking agent is provided. In the aqueous cathodic electrocoating composition, a bismuth-sugar solution is used to provide a catalytic amount of a bismuth compound dispersed in the electrocoating composition.
Claims20
A method for preparing a cathodic electrocoating composition, the method comprising:
- blending a binder resin with a crosslinking agent;
- neutralizing the binder resin to form an emulsion;
- blending a pigment dispersion with the emulsion;
- and
- blending a bismuth-sugar solution with the emulsion and/or with the pigment dispersion before blending the pigment dispersion with the emulsion, wherein the bismuth-sugar solution includes a catalytic amount of a bismuth compound.
A method for electrodepositing a coating, the method comprising:
- preparing an aqueous dispersion composition from a binder resin, a crosslinking agent, and a bismuth-sugar solution, wherein a catalytic amount of bismuth is dispersed in the aqueous dispersion composition;
- providing an electrochemical cell comprising:
- i) the aqueous dispersion composition;
- ii) a substrate to be coated, wherein the substrate is in contact with the aqueous dispersion composition and the substrate serves as a cathode of the electrochemical cell;
- iii) an anode in contact with the aqueous dispersion composition;
- and
- iv) a power supply in electrical contact with the anode and cathode;
- applying a voltage between the cathode and the anode to electrodeposit the coating onto at least a portion of the substrate;
- and
- curing the coating by baking the coating and substrate at a low bake temperature of less than 130° C.
A method for preparing a bismuth-sugar solution, the method comprising:
- dissolving a polyhydroxy compound in water to form a polyhydroxy solution;
- combining a bismuth compound with the polyhydroxy solution to form a mixture;
- heating the mixture at a temperature of 40° C. to 100° C. to form a reaction product;
- and
- separating a solid from the reaction product to form the bismuth-sugar solution, wherein the bismuth-sugar solution has a bismuth content of at least 100 g/L and a pH of greater than 1.
Dependencies are inferred from the claim text.