Device for predicting amount of coarse flakes in coating compositions by wet color measurement
The present invention is directed to a device for predicting amount of coarse flakes, such as metallic aluminum flakes present in a coating composition, such as automotive OEM or refinish paint. The device includes measuring flop of a layer of the coating composition applied over a test substrate by using flop prediction device of the present invention. 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 and then by using a curve fitting equation, a flake amount prediction curve 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 then be predicted by using the flake amount prediction curve. The device is most useful during the manufacture of coating compositions, such as automotive OEM and refinishes paints.
1. A flake prediction device for predicting amount of coarse flakes in a target coating composition, comprising:
a test substrate mounted on a driver that is mounted on a support frame;
a vessel positioned adjacent to said test substrate such that a S0 coating composition when poured in said vessel can be dispensed as a L0 layer of substantially uniform thickness on a surface of said test substrate through an opening provided on said vessel, the S0 coating composition comprising F0 parts by weight of said coarse flakes based on 100 parts by weight of said S0 coating composition;
an optical measurement mechanism for projecting on said L0 layer a beam of light of a preset intensity at a preset angle of incidence from a light source;
an optical measurement instrument to measure B0 flop of said beam reflected from said L0 layer at a preset angle of reflectance;
a computer configured to:
store said B0 flop of said L0 layer in a computer usable storage medium of the computer;
store B1 to Bn flops of L1 to Ln layers resulting from S1 to Sn coating compositions respectively comprising F1 to Fn parts by weight of said coarse flakes based on 100 parts by weight respectively of said S1 to Sn coating compositions, wherein n ranges from 1 to 100;
locate intersecting points on a graph where said B0 to Bn flops of said L0 to Ln layers laying on X-axis of said graph intersect with said F0 to Fn parts by weight of said coarse flakes laying on Y-axis of said graph;
utilize a curve fitting equation to produce a flake amount prediction curve on said graph;
store BT flop of LT layer of said substantially uniform thickness of a target coating composition where said BT flop is obtained by projecting said beam of light at said preset intensity and at said preset angle of incidence from said light 35 source, said target coating composition further comprising said coarse flakes;
locate said BT flop of said LT layer on said X-axis of said graph;
locate an intersecting point on said flake amount prediction curve that intersects with said BT flop on said X-axis of said graph;
predict 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; and
present said predicted amount YT of said coarse flakes contained in said target composition.
2. The device of claim 1 wherein said optical measurement device is a spectrophotometer.
3. The device of claim 1 wherein said optical measurement instrument is in communication with said computer.
4. The device of claim 1 wherein said coarse flakes have a size ranging from approximately 25 microns to approximately 2000 microns.
5. The device of claim 1 wherein said opening is a slot adjacent to said test substrate such that a resulting gap between said slot and said test substrate controls the thickness of said L0 to Ln layers.
6. The device of claim 1 wherein said L0 to Ln layers are of the same thickness ranging from approximately 6 micrometers to approximately 2300 micrometers.
7. The device of claim 1 wherein said test substrate is a disc positioned substantially vertically on a support frame of said flake prediction device.
8. The device of claim 1 wherein said curve fitting equation is a second degree polynomial equation.
9. The device of claim 8 wherein said second degree polynomial equation is of the formula:
Flop Y=a ( B n ) 2+ b ( B n )+ c
R 2= Z
wherein said constants a, b, c and Z are determined by a curve fitting process.
10. The device of claim 1 comprising displaying said predicted amount of said coarse flakes contained in said target coating composition on a CRT monitor.
11. The device of claim 1 comprising communicating said predicted amount of said coarse flakes contained in said target coating composition from said computer to a remote computer.
12. The device of claim 1 wherein said target coating composition is an automotive OEM paint.
13. The device of claim 1 wherein said coarse flakes comprise aluminum flakes.
14. The device of claim 1 wherein said target coating composition is an automotive refinish paint.
15. The device of claim 1 wherein said coarse flakes comprise mica flakes.
16. The device of claim 1 wherein said coarse flakes comprise inorganic flakes.
17. The device of claim 1 wherein said coarse flakes comprise organic flakes.