Patent ID: 11898052
Assignee: KANSAI PAINT CO., LTD.
Field: Macromolecular chemistry, polymers (Chemistry)
Classification: CPC C  B | IPC B  C

Claim 7:
8. A method for forming a multilayer coating film in which the following steps (1) to (4) are carried out in order:
step (1): a step of applying a water-based first colored coating material (X) onto an article to be coated to form a first colored coating film,
step (2): a step of applying a water-based second colored coating material (Y) onto the first colored coating film formed in step (1), to form a second colored coating film,
step (3): a step of applying a clear coating material (Z) onto the second colored coating film formed in step (2) to form a clear coating film, and
step (4): a step of heat curing the first colored coating film, the second colored coating film and the clear coating film formed in steps (1) to (3) all at once,
wherein the water-based first colored coating material (X) is a water-based coating composition comprising:
at least one type of resin selected from among acrylic resin (A) and polyester resin (B),
a curing agent (C), and
urethane resin particles (D) obtained from a constituent component including a polyisocyanate component (d1) comprising at least one type of diisocyanate (d1-1) selected from among xylylene diisocyanates and hydrogenated xylylene diisocyanates, and a polyol component (d2),
wherein a content ratio of the diisocyanate (d1-1) in the polyisocyanate component (d1) of the urethane resin particles (D) is in a range of 20 to 100 mass %, based on a total solid content of the polyisocyanate component (d1),
wherein the polyol component (d2) comprises a polyether polyol (d2-1) and a polycarbonate polyol (d2-2), and
the content ratio of the polyether polyol (d2-1) and the polycarbonate polyol (d2-2) in the polyol component (d2) is 90/10 to 60/40, as the mass ratio of polyether polyol (d2-1)/polycarbonate polyol (d2-2).