Coating method and coated article obtained by the same

A coating method for forming a multilayer coating film including at least one lower layer formed on a substrate and an uppermost layer formed on the lower layer, the coating method comprising the steps of:

• preparing a thermosetting coating material as an uppermost layer-coating material for forming the uppermost layer, wherein the thermosetting coating material has a curing temperature TT of 40° C. to 200° C. both inclusive and forms no volatile product in a curing reaction by a heat treatment, and preparing a lower layer-thermosetting coating material as at least one lower layer-coating material for forming the lower layer, wherein the lower layer-thermosetting coating material has a curing temperature Tu that satisfies the following formula (1):
• TU≦TT−30 (1)
• (in the formula (1), Tu represents a curing temperature ° C. of the lower layer-thermosetting coating material, and TT represents the curing temperature ° C. of the uppermost layer-thermosetting coating material);
• forming an uncured multilayer coating film by applying the lower layer-coating material and the uppermost layer-coating material on the substrate using a wet-on-wet technique;
• setting heating temperatures TL and TH that satisfy the following formula (2):
• TU−20≦TL≦TT−30 (2),
• and the following formula (3):
• TT−20≦TH≦TT+40 (3)
• (in the formulas (2) and (3), TL represents a temperature ° C. for low temperature heating, TH represents a temperature ° C. for high temperature heating, and TU and TT are the same as TU and TT in the formula (1));
• and
• forming a multilayer coating film including the uncured uppermost layer by subjecting the uncured multilayer coating film to the heat treatment at the temperature T1to thus cure at least the lower layer-thermosetting coating material, and then curing the uppermost layer-thermosetting coating material by subjecting the multilayer coating film including the uncured uppermost layer to the heat treatment at the temperature TH.

A coating method for forming a multilayer coating film including at least one lower layer formed on a substrate and an uppermost layer formed on the lower layer, the coating method comprising the steps of:

• preparing a curable coating material as an uppermost layer-coating material for forming the uppermost layer, wherein the curable coating material forms a cross-linked structure by a chemical reaction, and preparing a coating material as at least one lower layer-coating material for forming the lower layer, wherein the coating material has a relative loss elastic modulus of 1 s−2 or less when the uppermost layer-coating material starts to gel;
• forming an uncured multilayer coating film by applying the lower layer-coating material and the uppermost layer-coating material on the substrate using a wet-on-wet technique;
• and
• curing at least the uppermost layer-coating material by subjecting the uncured multilayer coating film to a curing treatment.