Process for predicting amount of coarse flakes in coating compositions by wet color measurement

摘要

A process for predicting an amount of coarse flakes, such as metallic aluminum flakes, present in a coating composition, such as automotive paint. The process includes measuring flop of a layer of the coating composition applied over a test substrate by using a flop prediction device. The process is repeated with varying amounts of one or more different types of coarse flakes added to the composition and the flop vs. amount of coarse flakes present in the coating composition is plotted on a graph. By using a curve fitting equation, a flake amount prediction curve then is obtained. By measuring the flop of a wet layer of a target coating composition, the amount of coarse flakes present in the target coating composition can be predicted by using the flake amount prediction curve.

主权项

1. A process for predicting amount of coarse flakes in a target coating composition comprising:
(a) adding to a vessel of a flake prediction device a S0 coating composition comprising F0 parts by weight of said coarse flakes based on 100 parts by weight of said S0 coating composition; (b) dispensing from an opening in said vessel said S0 coating composition over a test substrate to produce a L0 layer of a substantially uniform thickness thereon; (c) projecting on said L0 layer a beam of light of a preset intensity at a preset angle of incidence from a light source; (d) measuring B0 flop of said beam reflected from said L0 layer at a preset angle of reflectance by an optical measurement instrument; (e) storing said B0 flop of said L0 layer in a computer usable storage medium of a computer; (f) repeating said steps (a) through (f) for S1 to Sn coating compositions respectively comprising F1 to Fn parts by weight of said coarse flakes based on 100 parts by weight of said S1 to Sn coating compositions to determine B1 to Bn flops of L1 to Ln layers wherein n ranges from 1 to 100; (g) locating intersecting points on a graph where said B0 to Bn flops of said L0 to Ln layers on X-axis of said graph intersect with said F0 to Fn parts by weight of said coarse flakes on Y-axis of said graph; (h) using a curve fitting equation to produce a flake amount prediction curve on said graph; (i) dispensing on said test substrate a LT layer of said substantially uniform thickness of said target coating composition from said vessel wherein said target coating composition contains said coarse flakes; (j) projecting on said LT layer a beam of light at said preset intensity and at said preset angle of incidence from said light source; (k) measuring BT flop of said beam reflected from said LT layer at said preset angle of reflectance by said optical measurement device; (l) locating said BT flop of said LT layer on said X-axis of said graph; (n) locating an intersecting point on said flake amount prediction curve that intersects with said BT flop on said X-axis of said graph; and (p) predicting amount of said coarse flakes contained in said target composition by locating YT on said Y-axis of said graph that intersects with said intersecting point on said flake amount prediction curve that intersects with said BT on said X-axis of said graph.