Patent ID: 8808447

Claim:
A method for preparing a pigment for exterior materials comprising: (a) forming a pigment powder by coating an oxide layer including MgO·SiO 2 on surfaces of flakes used as a matrix; (b) forming a suspension having a solid content of 5% by weight (wt %) to 20 wt % by mixing the pigment powder with DI water, followed by stirring and dispersing the mixture; (c) dumping CeCl 3 to the suspension, followed by stirring for 5 minutes to 30 minutes; (d) heating the suspension of (c) to 60° C. to 90° C., followed by stirring for 10 minutes to 60 minutes; (e) refluxing the suspension of (d) for 5 minutes to 30 minutes after adjusting a pH thereof to 1 to 5; (f) mixing the suspension of (e) with an Al(NO 3 ) 3 solution to maintain a constant pH and refluxing the suspension for 10 minutes to 60 minutes after injection of the solution; (g) adjusting the pH of the suspension of (f) to 3 to 9 while stirring the suspension; and (h) injecting a silane coupling solution into the suspension having an increased pH in (g) to maintain the pH and refluxing the suspension for 10 minutes to 30 minutes after injection of the silane coupling solution.