Coating compositions for application utilizing a high transfer efficiency applicator and methods and systems thereof

1. A method of applying a coating composition to a substrate utilizing a high transfer efficiency applicator, said method comprising the steps of:

providing the high transfer efficiency applicator comprising an array of nozzles wherein each nozzle defines a nozzle orifice having a diameter of from 0.00002 m to 0.0004 m;

providing the coating composition; and

applying the coating composition to the substrate through the nozzle orifice without atomization such that at least 99.9% of the applied coating composition contacts the substrate to form a coating layer having a wet thickness of at least 5 microns;

wherein the coating composition comprises:

a carrier;

a binder present in an amount of from 5 to about 70 weight percent based on a total weight of the coating composition;

a crosslinker present in an amount of from about 0.1 to about 25 weight percent based on a total weight of the coating composition; and

a radar reflective pigment or a LiDAR reflective pigment; and

wherein the coating composition has

(1) a solids content of from about 5 to about 70 weight % based on a total weight of the coating composition as measured in accordance with ASTM D2369;

(2) a viscosity of from about 0.002 Pa*s to about 0.2 Pa*s as measured according to ASTM 7867-13 with cone-and-plate or parallel plates at a shear rate of 1000 sec−1;

(3) a density of from about 838 kg/m 3 to about 1557 kg/m 3 ;

(4) a surface tension of from about 0.015 N/m to about 0.05 N/m;

(5) a relaxation time of from about 0.00001 to about 1 s;

(6) an Ohnesorge number (Oh) of from about 0.01 to about 12.6 that is determined in accordance with equation I, as follows:

Oh =(η/√{square root over (ρσ D )})  (I),

wherein η represents viscosity of the coating composition in pascal-seconds (Pa*s), ρ represents density of the coating composition in kilograms per cubic meter (kg/m 3 ), σ represents surface tension of the coating composition in newtons per meter (N/m), and D represents nozzle diameter of the high transfer efficiency applicator in meters (m);

(7) a Reynolds number (Re) of from about 0.02 to about 6,200 that is determined in accordance with equation II, as follows:

Re =(ρ vD /η)  (II),

wherein ρ represents density of the coating composition in kilograms per cubic meter (kg/m 3 ), v represents impact velocity of the high transfer efficiency applicator in meters per second (m/s), D represents nozzle diameter of the high transfer efficiency applicator in meters (m), and η represents viscosity of the coating composition in pascal-seconds (Pa*s); and

(8) a Deborah number (De) of from greater than 0 to about 1730 that is determined in accordance with equation III, as follows:

De =λ/√{square root over (ρ D 3 /σ)}  (III),

wherein λ represents relaxation time of the coating composition in seconds (s), ρ represents density of the coating composition in kilograms per cubic meter (kg/m 3 ), D represents nozzle diameter of the high transfer efficiency applicator in meters (m), and σ represents surface tension of the coating composition in newtons per meter (N/m); and

wherein the impact velocity is from about 0.2 m/s to about 20 m/s.

2. The method of claim 1 , wherein the Ohnesorge number (Oh) is from 0.01 to 12.6 and is further defined based upon the following equations V and VI, in view of the Reynolds number (Re),

Oh is no greater than 10{circumflex over ( )}(−0.5006*log( Re )+1.2135)  (V), and

Oh is at least 10{circumflex over ( )}(−0.5435*log( Re )−1.0324)  (VI),

wherein the Reynolds number (Re) is from 0.02 to 6,200.

3. The method of claim 1 , wherein the coating composition has an Ohnesorge number (Oh) of from about 0.05 to about 1.8, a Reynolds number (Re) of from about 0.3 to about 660, and a Deborah number (De) of from greater than 0 to about 46.

4. The method of claim 3 , wherein the Ohnesorge number (Oh) is further defined based upon the following equations VII and VIII, in view of the Reynolds number (Re),

Oh is no greater than 10{circumflex over ( )}(−0.5067*log( Re )+0.706)  (VII), and

Oh is at least 10{circumflex over ( )}(−0.5724*log( Re )−0.4876)  (VIII),

wherein the Reynolds number (Re) is from 0.3 to 660.

5. The method of claim 1 , wherein the coating composition comprises the LiDAR reflective pigment in an amount of from about 0.1 to about 5 wt % based on a total weight of the coating composition.

6. The method of claim 2 , wherein the coating composition comprises the LiDAR reflective pigment in an amount of from about 0.1 to about 5 wt % based on a total weight of the coating composition.

7. The method of claim 3 , wherein the coating composition comprises the LiDAR reflective pigment in an amount of from about 0.1 to about 5 wt % based on a total weight of the coating composition.

8. The method of claim 4 , wherein the coating composition comprises the LiDAR reflective pigment in an amount of from about 0.1 to about 5 wt % based on a total weight of the coating composition.

9. The method of claim 1 , wherein the coating composition is substantially free of a dye.

10. The method of claim 1 , wherein the coating composition further comprises a solvent selected from the group of water, a non-aqueous solvent, and a combination thereof.

11. The method of claim 1 , wherein the coating composition has a viscosity of from about 0.005 Pa*s to about 0.05 Pa*s as measured according to ASTM 7867-13 with cone-and-plate or parallel plates at a shear rate of 1000 sec−1, a density of from about 958 kg/m 3 to about 1319 kg/m 3 , and a surface tension of from about 0.02 N/m to about 0.032 N/m.

12. The method of claim 2 , wherein the coating composition has a viscosity of from about 0.005 Pa*s to about 0.05 Pa*s as measured according to ASTM 7867-13 with cone-and-plate or parallel plates at a shear rate of 1000 sec−1, a density of from about 958 kg/m 3 to about 1319 kg/m 3 , and a surface tension of from about 0.02 N/m to about 0.032 N/m.

13. The method of claim 3 , wherein the coating composition has a viscosity of from about 0.005 Pa*s to about 0.05 Pa*s as measured according to ASTM 7867-13 with cone-and-plate or parallel plates at a shear rate of 1000 sec−1, a density of from about 958 kg/m 3 to about 1319 kg/m 3 , and a surface tension of from about 0.02 N/m to about 0.032 N/m.

14. The method of claim 4 , wherein the coating composition has a viscosity of from about 0.005 Pa*s to about 0.05 Pa*s as measured according to ASTM 7867-13 with cone-and-plate or parallel plates at a shear rate of 1000 sec−1, a density of from about 958 kg/m 3 to about 1319 kg/m 3 , and a surface tension of from about 0.02 N/m to about 0.032 N/m.

15. The method of claim 5 , wherein the coating composition has a viscosity of from about 0.005 Pa*s to about 0.05 Pa*s as measured according to ASTM 7867-13 with cone-and-plate or parallel plates at a shear rate of 1000 sec−1, a density of from about 958 kg/m 3 to about 1319 kg/m 3 , and a surface tension of from about 0.02 N/m to about 0.032 N/m.

16. The method of claim 1 wherein

the coating composition has an Ohnesorge number (Oh) of from about 0.05 to about 1.8, a Reynolds number (Re) of from about 0.3 to about 660, and a Deborah number (De) of from greater than 0 to about 46;

the coating composition comprises the LiDAR reflective pigment in an amount of from about 0.1 to about 5 wt % based on a total weight of the coating composition;

the coating composition is substantially free of a dye;

the coating composition further comprises a solvent selected from the group of water, a non-aqueous solvent, and a combination thereof; and

the coating composition has a viscosity of from about 0.005 Pa*s to about 0.05 Pa*s as measured according to ASTM 7867-13 with cone-and-plate or parallel plates at a shear rate of 1000 sec−1, a density of from about 958 kg/m 3 to about 1319 kg/m 3 , and a surface tension of from about 0.02 N/m to about 0.032 N/m.