COATING METHOD AND COATED BODY OBTAINED BY THE METHOD

PROBLEM TO BE SOLVED: To provide a coating method whereby a laminated coating film in which occurrence of roughness of an upper-layer surface is sufficiently restricted can be obtained even when three or more types of coating materials are layered in a wet-on-wet manner and they are simultaneously baked to cure each layer.SOLUTION: A coating method for forming a laminated coating film comprising a lower layer formed on a base material, an intermediate layer formed on the lower layer, and an upper layer formed on the intermediate layer, comprises: a preparation step in which a thermoplastic coating material is prepared as a lower-layer coating material, an intermediate-layer coating material, and an upper-layer coating material; a formation step in which an uncured laminated coating film is formed by layering, on the base material, the lower-layer coating material, the intermediate-layer coating material, and the upper-layer coating material in a wet-on-wet manner; and a baking step in which the uncured laminated coating film is subjected to a baking process, thereby simultaneously curing the lower-layer coating material, the intermediate-layer coating material, and the upper-layer coating material. In the preparation step, if the contraction coefficients of the upper-layer coating material, a first adjacent-layer coating material, which is adjacent to the upper layer, and a second adjacent-layer coating material, which is adjacent to the first adjacent-layer, for a period after the flow stop time tof the upper-layer coating material to the termination of a standard baking time tare ω, ω, and ω, respectively, the upper-layer coating material, the first adjacent-layer coating material, and the second adjacent-layer coating material are selected so that the sum of the absolute value of the difference between the contraction coefficient ωand the contraction coefficient ωand the absolute value of the difference between the contraction coefficient ωand the contraction coefficient ωis 8.0% or less.SELECTED DRAWING: None 【課題】３種類以上の塗料をウェットオンウェットで積層して同時に焼付けて各層を硬化させても、上層表面の凹凸の発生が十分に抑制された積層塗膜を得ることができる塗装方法を提供すること。【解決手段】基材上に形成された下層と該下層上に形成された中間層と該中間層上に形成された上層とを備える積層塗膜を形成する塗装方法であって、下層用塗料、中間層用塗料及び上層用塗料として熱硬化型塗料を準備する準備工程と、基材上に下層用塗料、中間層用塗料及び上層用塗料をウェットオンウェットで積層して未硬化積層塗膜を形成する形成工程と、未硬化積層塗膜に焼付け処理を施して下層用塗料、中間層用塗料及び上層用塗料を同時に硬化させる焼付工程と、を含んでおり、前記準備工程において、上層用塗料の流動停止時間ｔｃＵ後から各塗料の標準焼付け時間ｔｂ終了時までの間の上層用塗料、上層に隣接する第一の隣接層用塗料及び第一の隣接層に隣接する第二の隣接層用塗料の収縮率をωＵ、ωＡ１及びωＡ２とするとき、前記収縮率ωＵと前記収縮率ωＡ１との差の絶対値と