Clear coating compositions comprising particulate inorganic mineral
The present invention describes clear coating compositions comprising a particulate inorganic mineral, wherein the d 50 of the particulate inorganic mineral is less than about 1 μm, and wherein the mineral includes a kandite clay.
1. A clear coating composition comprising a particulate inorganic mineral, wherein the d 50 of the particulate inorganic mineral is less than about 1 μm, the wt % of the particulate inorganic mineral less than 0.1 μm as measured according to the disc centrifuge method is 40 wt % or less, and wherein the mineral comprises a kandite clay, and the particulate inorganic mineral has a steepness factor that ranges from about 20 to about 75, and
wherein the coating composition has a transmittance greater than about 90% when the coating composition comprises up to about 25 wt % of the mineral based on the total weight of the coating composition.
2. The clear coating composition according to claim 1 , wherein the kandite clay is at least one of kaolin or halloysite.
3. The clear coating composition according to claim 1 , wherein the wt % of particulate inorganic mineral less than 0.1 μm as measured according to the disc centrifuge method is 10 wt % or less.
4. The clear coating composition according to claim 1 , wherein the wt % of particulate inorganic mineral less than 0.1 μm as measured according to the disc centrifuge method is 20 wt % or less.
5. The clear coating composition according to claim 1 , wherein the wt % of particulate inorganic mineral less than 0.1 μm as measured according to the disc centrifuge method is 5 wt % or less.
6. The clear coating composition according to claim 1 , wherein the wt % of particulate inorganic mineral less than 0.1 μm as measured according to the disc centrifuge method is 1 wt % or less.
7. The clear coating composition according to claim 1 , wherein the wt % of particulate inorganic mineral less than 0.1 μm as measured according to the disc centrifuge method is at least about 0.1 wt %.
8. The clear coating composition according to claim 1 , wherein the d 50 of the particulate inorganic mineral is less than about 0.6 μm.
9. The clear coating composition according to claim 1 , wherein the d 50 of the particulate inorganic mineral is less than about 0.5 μm.
10. The clear coating composition according to claim 1 , wherein the d 50 of the particulate inorganic mineral is less than about 0.4 μm.
11. The clear coating composition according to claim 1 , wherein the d 50 of the particulate inorganic mineral is at least about 0.15 μm.
12. The clear coating composition according to claim 1 , wherein the aspect ratio of the particulate inorganic mineral is greater than about 10.
13. The clear coating composition according to claim 1 , wherein the aspect ratio of the particulate inorganic mineral is greater than about 30.
14. The clear coating composition according to claim 1 , wherein the aspect ratio of the particulate inorganic mineral ranges from about 10 to about 70.
15. The clear coating composition according to claim 14 , wherein the aspect ratio of the particulate inorganic mineral ranges from about 20 to about 50.
16. The clear coating composition according to claim 1 , wherein the mineral is kaolin and the steepness factor ranges from about 20 to about 45.
17. The clear coating composition according to claim 1 , wherein the coating composition comprises a polymer resin.
18. The clear coating composition according to claim 1 , wherein the composition comprises an organic solvent.
19. The clear coating composition according to claim 1 , wherein the composition is an aqueous based dispersion.
20. The clear coating composition according to claim 1 , wherein the coating composition comprises up to about 20 wt % of the mineral based on the total weight of the clear composition.
21. The clear coating composition according to claim 1 , wherein the coating composition comprises up to about 15 wt % of the mineral based on the total weight of the clear composition.
22. The clear coating composition according to claim 1 , wherein the coating composition comprises at least about 2 wt % of the mineral based on the total weight of the clear composition.
23. The clear coating composition according to claim 1 , wherein the coating composition comprises at least about 5 wt % of the mineral based on the total weight of the clear composition.
24. The clear coating composition according to claim 1 , wherein the coating is a matt composition, and wherein the matt composition has a gloss (60°)<90 measured in accordance with ASTM D523.
25. The clear coating composition according to claim 24 , wherein the matt composition has a gloss (60°)<80 measured in accordance with ASTM D523.
26. The clear coating composition according to claim 25 , wherein the matt composition has a gloss (60°)<60 measured in accordance with ASTM D523.
27. The clear coating composition according to claim 26 , wherein the matt composition has a gloss (60°)<50 measured in accordance with ASTM 0523.
28. The clear coating composition according to claim 24 , wherein the matt composition has a gloss (60°)>5 measured in accordance with ASTM D523.
29. A production process for making the clear coating composition according to claim 1 , the process comprising blending said mineral and other components of the clear coating composition.
30. A method for coating an article or substrate comprising:
coating said article or substrate with the clear coating composition according to claim 1 ; and
curing the coating composition.
31. An article or substrate coated with a clear coating composition according to claim 1 .
32. The clear coating composition according to claim 1 , wherein the particulate inorganic mineral has a BET surface area greater than about 10 m 2 g −1 .
33. The clear coating composition according to claim 1 , wherein the coating composition has a haze less than about 40.