Polyurethane coating composition
A coating composition, coated article and method for coating an article are provided. The composition is a coating composition that includes a polyurethane binder system further including a first resin component and a second resin component with a significant difference in hydroxyl numbers and crosslinked with an isocyanate. The composition, when applied to and cured on an article, imparts optimal antifingerprint, antireflecting, tactile, chemical agent-resistant, and self-healing effects to the coated article.
1. A coating composition, comprising:
a polyurethane binder resin system comprising:
a first resin component with a hydroxyl number of 150 to 240;
a second resin component with a hydroxyl number of 15 to 35,
wherein the difference in hydroxyl number of the first and second resin component is 135 to 215; and
a hydroxyl-reactive crosslinker,
wherein the coating composition is substantially free of filler, and
wherein a cured coating formed from the coating composition has oleophobic and hydrophobic properties, and has 60°-gloss of less than about 5.
2. The composition of claim 1 , wherein a cured coating formed from the composition has 20°-gloss of less than about 1.
3. The composition of claim 1 , wherein a cured coating formed from the coating composition has surface roughness (Rz) of about 10 to 30 μm.
4. The composition of claim 1 , wherein the first resin component is a hydroxyl-functional polyester.
5. The composition of claim 1 , wherein the second resin component is a hydroxyl-functional polyester.
6. The composition of claim 1 , wherein the hydroxyl-reactive crosslinker is an isocyanate.
7. The composition of claim 1 , wherein the hydroxyl-reactive crosslinker is a blocked isocyanate.
8. The composition of claim 1 , wherein the first resin component has Tg of about 40° C. to 70° C.
9. The composition of claim 1 , wherein the second resin component has Tg of about 40° C. to 70° C.
10. The composition of claim 1 , wherein the difference in Tg (ΔTg) of the first and second resin components is no more than 10° C.
11. The composition of claim 1 , wherein the crosslinker is present in NCO:OH ratio of 1:1.5 to 1:1.1.
12. The composition of claim 1 , wherein a cured coating formed from the composition has self-healing effect when an external thermal stimulus is applied.
13. The composition of claim 1 , wherein a cured coating formed from the composition has self-healing effect at ambient temperature.
14. The composition of claim 1 , wherein a cured coating formed from the composition has self-healing effect at temperatures of above 90° C.
15. A coating composition, comprising a polyurethane binder resin system comprising:
a first resin component with a hydroxyl number of 150 to 240;
a second resin component with a hydroxyl number of 15 to 35,
wherein the difference in hydroxyl number of the first and second resin component is 135 to 215;
a hydroxyl-reactive crosslinker, and
wherein a cured coating formed from the coating composition has oleophobic and hydrophobic properties, and has 60°-gloss of less than about 5, and
wherein the composition comprises less than 5 wt % filler, based on the total weight of the composition.