Thermosetting powder coating composition and method for forming a topcoat using the same
申请人:KANSAI PAINT CO., LTD.
公开号:US20030027939A1
公开(公告)日:2003-02-06
The present invention provides a method for forming a topcoat according to a 2-coat 1-bake system comprising the steps of applying to a substrate a thermosetting aqueous colored base coating composition, applying to the uncured surface of the base coat a clear coating composition, and curing the two coats by heating, wherein the clear coating composition is a thermosetting powder coating composition comprising: (A) an epoxy-containing resin; and (B) a curing agent containing acid anhydride (a) represented by formula
X—COO—[CO—(CH
2
)
m
—COO]
n
—CO—X (
1
)
and at least one species selected from the group consisting of acid anhydride (b) represented by the formula
HO—[CO—(CH
2
)
p
—COO]
q
—H (
2
)
and dibasic acid (c).
本发明提供了一种形成顶层涂层的方法,该方法采用2层1烘烤系统,包括以下步骤:向基材涂覆一种热固性水性着色底漆组合物;向未固化的底漆表面涂覆一种清漆组合物;通过加热使两层涂层固化。其中,所述清漆组合物是一种热固性粉末涂料组合物,包括:(A)含环氧基的树脂;以及(B)含有酸酐(a)的固化剂,其表示为公式X—COO—[CO—(CH2)m—COO]n—CO—X(1),并且至少选择一种来自于酸酐(b)的组别,其表示为公式HO—[CO—(CH2)p—COO]q—H(2),和二元酸(c)。