Solvent for urethane adhesives and coatings and method of use
View Patent ↗A solvent for urethane adhesives and coatings, the solvent having a carbaldehyde and a cyclic amide as constituents. In some embodiments the solvent consists only of miscible constituents. In some embodiments the carbaldehyde is benzaldehyde and in some embodiments the cyclic amide is N-methylpyrrolidone (M-pyrole). An extender may be added to the solvent. In some embodiments the extender is miscible with the other ingredients, and in some embodiments the extender is non-aqueous. For example, the extender may include isopropanol, ethanol, tetrahydro furfuryl alcohol, benzyl alcohol, Gamma-butyrolactone or a caprolactone. In some embodiments a carbaldehyde and a cyclic amide are heated and used to separate a urethane bonded to a component.
1. A miscible solvent comprising from about 20 to about 80 wt % carbaldehyde and from about 20 to about 80 wt % cyclic amide.
2. The solvent of claim 1 wherein the carbaldehyde comprises benzaldehyde or a structural analog thereof.
3. The solvent of claim 2 wherein the cyclic amide comprises N-methylpyrrolidone or a structural analog thereof.
4. The solvent of claim 3 wherein the solvent comprises from about 20 to about 30 wt % benzaldehyde or a structural analog thereof and from about 70 to about 80 wt % N-methylpyrrolidone or a structural analog thereof.
5. The solvent of claim 3 wherein the solvent comprises from about 30 to about 40 wt % benzaldehyde or a structural analog thereof and from about 60 to about 70 wt % N-methylpyrrolidone or a structural analog thereof.
6. The solvent of claim 3 wherein the solvent comprises from about 40 to about 60 wt % benzaldehyde or a structural analog thereof and from about 40 to about 60 wt % N-methylpyrrolidone or a structural analog thereof.
7. The solvent of claim 1 wherein cyclic amide comprises N-methylpyrrolidone or a structural analog thereof.
8. The solvent of claim 1 further comprising an extender.
9. A solvent consisting essentially of from about 20 to about 80 wt % carbaldehyde, from about 20 to about 80 wt % cyclic amide, and up to about 60 wt % non-aqueous extender.
10. The solvent of claim 9 wherein the carbaldehyde comprises benzaldehyde or a structural analog thereof.
11. The solvent of claim 10 wherein the cyclic amide comprises N-methylpyrrolidone or a structural analog thereof.
12. The solvent of claim 11 wherein the solvent comprises from about 20 to about 30 wt % benzaldehyde or a structural analog thereof and from about 70 to about 80 wt % N-methylpyrrolidone or a structural analog thereof.
13. The solvent of claim 11 wherein the solvent comprises from about 30 to about 40 wt % benzaldehyde or a structural analog thereof and from about 60 to about 70 wt % N-methylpyrrolidone or a structural analog thereof.
14. The solvent of claim 11 wherein the solvent comprises from about 40 to about 60 wt % benzaldehyde or a structural analog thereof and from about 40 to about 60 wt % N-methylpyrrolidone or a structural analog thereof.
15. The solvent of claim 9 wherein the cyclic amide comprises N-methylpyrrolidone or a structural analog thereof.
16. The solvent of claim 9 wherein the non-aqueous extender comprises one or more chemicals selected from the group consisting of isopropanol, ethanol, tetrahydro furfuryl alcohol, benzyl alcohol, and a caprolactone.
17. A method for separating a urethane bonded to a component at a bond interface, the urethane having an exposed surface, the method comprising the steps of:
(a) contacting the exposed surface with a solvent comprising a carbaldehyde and a cyclic amide for a period of time until the bond interface is weakened, the solvent being heated to a temperature above ambient temperature for at least a portion of the period of time; and
(b) separating the component from the urethane at the bond interface.
18. The method of claim 17 wherein step (a) comprises contacting the exposed surface with a solvent comprising a carbaldehyde and N-methylpyrrolidone or a structural analog thereof.
19. The method of claim 18 wherein step (a) comprises contacting the exposed surface with a solvent comprising benzaldehyde or a structural analog thereof and N-methylpyrrolidone or a structural analog thereof.
20. The method of claim 19 wherein step (a) comprises contacting the exposed surface with a solvent comprising from about 20 to about 30 wt % benzaldehyde or a structural analog thereof and from about 70 to about 80 wt % N-methylpyrrolidone or a structural analog thereof.
21. The method of claim 19 wherein step (a) comprises contacting the exposed surface with a solvent comprising from about 30 to about 40 wt % benzaldehyde or a structural analog thereof and from about 60 to about 70 wt % N-methylpyrrolidone or a structural analog thereof.
22. The method of claim 19 wherein step (a) comprises contacting the exposed surface with a solvent comprising from about 40 to about 60 wt % benzaldehyde or a structural analog thereof and from about 40 to about 60 wt % N-methylpyrrolidone or a structural analog thereof.
23. The method of claim 17 wherein step (a) comprises contacting the exposed surface with a solvent comprising benzaldehyde or a structural analog thereof and a cyclic amide.