Basf Coatings Gmbh

Honda Motor Co., Ltd.

Nissan Motor Company Limited

Basf Coatings Japan Limited

Hisayuki Nakashima

Takeshi Ogawa

Hardy Reuter

Satoshi Matsumoto

Souichi Mori

Yusuke Kurata

Yasufumi Honda

Kyohei Homma

Yusuke Yagi

Yohei Koyama

Hironori Tsutsui

Takamasa Miyamoto

Daiki Fujihira

Described herein are aqueous coating compositions including at least one dispersion of core/shell particles containing a polyurethane resin as core portion and a crosslinked acrylic resin as shell portion and at least one aqueous polyurethane-polyurea dispersion containing crosslinked polyurethane-polyurea particles. Also described herein is a method for forming a multilayer coating on a substrate using the aqueous coating compositions as basecoat compositions. Also described herein is a multicoat paint system produced by the method.

Water-based coating composition and method for forming multilayer coating film using said composition

Disclosed is a method for forming a multilayer coating film, including applying a first and second aqueous base coat, and a clear coat to an object, and thereafter simultaneously heating and curing the three-layer coating film. The first aqueous base coat includes a water-soluble or water-dispersible polyurethane resin having a glass transition temperature of &#x2212;20&#xb0; C. or below and a weight average molecular weight of 30,000 to 500,000, and a crosslinkable resin having a weight average molecular weight of 600 or more. The first aqueous base coat-coated film has a breaking strength of 2050 N/cm2 or more and a loss tangent (tan &#x3b4;) at &#x2212;20&#xb0; C. of 0.075 or more. The migration amount of a melamine resin from the second aqueous base coat-coated film layer to the first aqueous base coat-coated film layer is within 3% by mass of a total resin solid content of the first aqueous base coat.

Method for forming multilayer coating film

An multilayer coated film comprises a waterborne intermediate-coat coating material and a waterborne basecoat coating material both containing a core/shell type resin emulsion (A) in which the core portion is an acrylic resin (A1) and the shell portion is a polyurethane resin (A2), a water-soluble or water-dispersible polyurethane resin (B), a water-soluble or water-dispersible polyester resin (C), and a melamine resin (D), and, based on the combined resin solids content by mass of aforesaid components (A) to (C), the solids content by mass of component (A) is 5-25 mass %, the solids content by mass of component (B) is 45-65 mass %, the solids content by mass of component (C) is 20-40 mass %, and the solids content by mass of component (D) is 35-45 mass %.

Method for forming a multilayer coated film

A method of forming multi-layer paint films comprises forming a first base paint film, wherein an aqueous first base paint (A) is coated over an object; forming a second base paint film wherein a second aqueous base paint (B) is coated over the uncured first base paint film; forming a clear paint film wherein a clear paint (C) is coated over the uncured second based paint film; and heating and curing the first base paint film, the second base paint film, and the clear paint film at the same time and in which the aqueous first base paint (A) includes as the base resin a water-soluble or water-dispersible acrylic resin (A1) and one or more type of water-soluble or water-dispersible resin (A2), selected from among the polyester resins, polyurethane resins and acrylic-urethane resins, both (A1) and (A2) having a weight average molecular weight of from 10,000 to 100,000.

Method of forming a multi-layer paint film

To provide a method of forming a multi-layer paint film with which, even when applying three paint layers and baking the paint layer only once, it is possible to achieve a paint film appearance the same as that with the conventional baking twice method. [Means of Resolution] A method of forming a multi-layer paint film in which an aqueous first base-paint is painted on a base material on which an electro-deposition paint has been coated and a first base-paint layer is formed, an aqueous second base-paint is painted on said first base-paint layer as a wet-on-wet system and a second base-paint layer is formed and, moreover, a clear-paint is painted on the second base-paint layer as a wet-on-wet system and a clear-paint layer is formed and then the three paint layers are all baked at the same time which is characterized in that the aqueous first base-paint includes as essential components hydroxyl group containing non-ionic resin where ethylene oxide units and/or propylene oxide units are included in an amount of from 4 to 15 mass % in the resin and of which the resin acid value is less than 15 mgKOH/g and the hydroxyl group value is from 10 to 100 mgKOH/g, and crosslinking agent.

Method of forming multi-layer paint films

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Kanagawa, Japan

Hisayuki Nakashima