| 摘要 |
PROBLEM TO BE SOLVED: To provide a coating film which satisfies performances required for an exterior coating film, such as excellent coating film appearance, water resistance and impact resistance, even when a first base coating material is coated and a second base coating material is coated without performing preliminary drying, and to provide a method for forming a multi-layer coating film.SOLUTION: A method for forming a multi-layer coating film is provided in which an aqueous first base coating material (A) is coated over a cured coating film to form a first base coating film, an aqueous second base coating material (B) is coated over the first base coating film without carrying out preliminary drying to form a second base coating film, preliminary drying is carried out after the second base coating film forming step, a clear coating material (C) is coated over the second base coating film to form a clear coat coating film, and the three coating film layers are heated and cured simultaneously. In the method for forming a multi-layer coating film, the aqueous first base coating material (A) contains a polyurethane resin (A1) and titanium oxide (A2), and the mass content ratio of the titanium oxide (A2) is from 4 to 15 mass% with respect to a resin solid portion, and the solid portion of the aqueous first base coating material (A) is from 40 to 60 mass%. |
