METHODS OF MAKING POLYURETHANE COATED ARTICLES, AND ARTICLES MADE THEREFROM
A method of making a polyurethane coating can comprise: mixing an unblocked isocyanate component with a polyol component in the presence of a hydroxyl-free solvent and a catalyst to form a reaction mixture; depositing the reaction mixture onto a polymer substrate; and curing the reaction mixture on the substrate to form a polyurethane coated substrate. The polyurethane coated substrate can have a percent thinning of greater than or equal to 10%, e.g., without cracking or delamination when measured on a rectangular block having 90° angles.
1 . A method of making a polyurethane coating comprises:
mixing an unblocked isocyanate component with a polyol component in the presence of a hydroxyl-free solvent and a catalyst to form a reaction mixture;
depositing the reaction mixture onto a polymer substrate; and
curing the reaction mixture on the substrate to form a polyurethane coated substrate;
wherein the polyurethane coated substrate has a percent thinning of greater than or equal to 10% when formed over a rectangular block having 90° angles.
2 . The method of claim 1 , wherein the curing occurs in a period of less than or equal to 60 seconds.
3 . The method of claim 1 , wherein the hydroxyl-free solvent comprises a ketone.
4 . The method of claim 3 , wherein the hydroxy-free solvent comprises methyl ethyl ketone.
5 . The method of claim 1 , wherein the percent thinning is greater than or equal to 15%.
6 . The method of claim 5 , wherein the percent thinning is greater than or equal to 35%.
7 . The method of claim 1 , wherein the catalyst comprises dibutyl tin dilaurate.
8 . The method of claim 1 , wherein the isocyanate component is greater than or equal to 90% unblocked, based upon the total weight of the isocyanate component.
9 . The method of claim 8 , wherein the isocyanate component is greater than or equal to 95% unblocked, based upon the total weight of the isocyanate component.
10 . The method of claim 1 , wherein the polyol component has a hydroxyl equivalent weight of 100 to 900.
11 . The method of claim 1 , wherein a residence time from when the isocyanate component and the polyol component are combined, until application to the polymer substrate is less than a gel time for the reaction mixture.
12 . The method of claim 11 , wherein the residence time is less than or equal to 6 minutes.
13 . The method of claim 12 , wherein the residence time is less than or equal to 60 seconds.
14 . The method of claim 1 , wherein the substrate comprises polycarbonate.
15 . The method of claim 1 , wherein the polyol component comprises at least one of polyethylene glycol and polypropylene glycol.
16 . The method of claim 15 , wherein the polyol component comprises polyoxyethylene glycol.
17 . The method of claim 1 , wherein the isocyanate component comprises hexamethylene diisocyanate, toluene diisocyanate, or a combination comprising at least one of hexamethylene diisocyanate and toluene diisocyanate.
18 . The method of claim 1 , wherein the coating on the polyurethane coated substrate has a delta haze after Taber of less than or equal to 10%, as determined in accordance with ASTM D1044-08 using CS-10F wheels, a 500 gram load, and 100 cycles.
19 . The method of claim 1 , further comprising forming the polyurethane coated substrate, wherein the polyurethane coated substrate is thinned by greater than 10%.
20 . The method of claim 19 , wherein the forming is at least one of thermoforming, drapeforming, pressure forming, and in-mold decoration.
21 . The method of claim 1 , wherein the isocyanate component is solvated in methy ethyl keytone and methyl isobutyl ketone.
22 . The method of claim 1 , wherein the curing is a single cure with greater than or equal to 95% conversion of the isocyanate component.
23 . The method of claim 1 , wherein the isocyanate component comprises hexamethylene diisocyanate.
24 . A method of making a polyurethane coating comprises:
mixing an unblocked isocyanate component with a polyol component in the presence of a hydroxyl-free solvent and a catalyst to form a reaction mixture;
depositing the reaction mixture onto a polymer substrate;
curing the reaction mixture on the substrate to form a polyurethane coated substrate; and
thinning the polyurethane coated substrate, wherein the polyurethane coated substrate is thinned by greater than or equal to 10%.
25 . An article formed by the method of claim 24 .