Two-component solvent-based coating composition, method for coating a substrate, coated substrate, and use of such coating composition for improving erosion resistance

Abstract

The present disclosure relates to a two-component, solvent-based coating composition comprising i) a base component comprising one or more polyesterdiols with a hydroxyl value in the range of from 150 to 500 mg KOH/g and one or more organosilane-modified inorganic fillers, and ii) a polyisocyanate curing component. Said composition can be formulated such that it has a viscosity suitable for spray application (low viscosity under high shear rate) and yield coatings with very good erosion resistance. The present disclosure further relates to a method for coating a substrate using said two-component coating composition, to a coated substrate obtainable by such method, and to use of such coating composition for improving erosion resistance of a substrate.

1 . A two-component, solvent-based coating composition comprising:
 i) a base component comprising
 (A) one or more polyester diols having a hydroxyl value in the range of from 150 to 500 mg KOH/g polyester diol; 
 (B) optionally one or more hydroxyl-functional acrylate resins having a hydroxyl value in the range of from 75 to 500 mg KOH/g resin; and 
 (C) one or more organosilane-modified inorganic fillers; and 
   ii) a curing component comprising
 (D) one or more polyisocyanates, 
   in such amounts that the coating composition comprises:   5 to 50 wt % of the one or more polyester diols (A);   0 to 25 wt % of the one or more hydroxyl-functional acrylate resins (B);   10 to 70 wt % of the one or more organosilane-modified inorganic fillers (C);   5 to 40 wt % of the one or more polyisocyanates (D);   wherein the coating composition comprises one or more organic solvents in an amount in the range of from 5 to 35 wt %, and has a viscosity in the range of from 50 to 2,000 mPa·s.   
     
     
         2 . A two-component coating composition according to  claim 1 , wherein the one or more polyester diols (A) have a hydroxyl-value in the range of from 200 to 400 mg KOH/g polyester diol. 
     
     
         3 . A two-component coating composition according to  claim 1 , wherein the one or more polyester diols (A) are linear, aliphatic polyester diols. 
     
     
         4 . A two-component coating composition according to  claim 1 , wherein the coating composition comprises in the range of from 2 to 15 wt % of the one or more hydroxyl-functional acrylate resin (B). 
     
     
         5 . A two-component coating composition according to  claim 1 , wherein the one or more hydroxyl-functional acrylate resins (B) have a hydroxyl value in the range of from 175 to 400 mg KOH/g resin. 
     
     
         6 . A two-component coating composition according to  claim 1 , wherein the one or more organosilane-modified inorganic fillers (C) are organosilane-modified silicates. 
     
     
         7 . A two-component coating composition according to  claim 1 , wherein the one of more polyisocyanates are selected from the group consisting of uretdiones, tri-isocyanurates, and biurets of aliphatic di-isocyanates, and mixtures thereof. 
     
     
         8 . A two-component coating composition according to  claim 1  comprising the one or more organic solvents in an amount in the range of from 7.5 to 25 wt %. 
     
     
         9 . A two-component coating composition according to  claim 1  comprising:
 10 to 30 wt % of the one or more polyester diols (A); 
 0 to 25 wt % of the one or more hydroxyl-functional acrylate resins (B); 
 20 to 50 wt % of the one or more organosilane-modified inorganic fillers (C); 
 10 to 30 wt % of the one or more polyisocyanates (D); and 
 7.5 to 25 wt % of the one or more organic solvents. 
 
     
     
         10 . A two-component coating composition according to  claim 1 , wherein the coating composition has a viscosity in the range of from 1,000 to 10,000 mPa·s at a shear rate of 1 s −1 , and the coating composition has a viscosity at a shear rate of 1,000 s −1  that is 2 to 20 times lower than its viscosity at a shear rate of 1 s −1 . 
     
     
         11 . A method for coating a substrate comprising:
 applying the two-component coating composition according to  claim 1  to the substrate; and   allowing the applied coating composition to cure.   
     
     
         12 . A method according to  claim 11  wherein the two-component coating composition is applied to the substrate by spray application. 
     
     
         13 . A method according to  claim 11 , wherein the substrate is a substrate comprising one or more coating layers and the two-component coating composition is applied as a topcoat layer. 
     
     
         14 . A coated substrate obtainable by a method according to  claim 11 . 
     
     
         15 . The method of  claim 11 , further comprising improving erosion resistance of the substrate. 
     
     
         16 . A two-component coating composition according to  claim 1 , wherein the one or more polyester diols (A) have a hydroxyl-value in the range of from 250 to 350 mg KOH/g polyester diol. 
     
     
         17 . A two-component coating composition according to  claim 1 , wherein the one or more hydroxyl-functional acrylate resins (B) have a hydroxyl value in the range of from 250 to 350 mg KOH/g resin. 
     
     
         18 . A two-component coating composition according to  claim 1 , wherein the one of more polyisocyanates are selected from the group consisting of uretdiones, tri-isocyanurates, and biurets of hexamethylene di-isocyanate and isophorone di-isocyanate, and mixtures thereof. 
     
     
         19 . A two-component coating composition according to  claim 1  comprising the one or more organic solvents in an amount in the range of from 10 to 20 wt %. 
     
     
         20 . The method of  claim 11 , further comprising allowing the applied coating composition to cure at a temperature of at most 80° C.