Photochromic polyurethane laminate
View Patent ↗A photochromic polyurethane laminate wherein the photochromic polyurethane layer of the laminate has been crosslinked with a isocyanate-active prepolymer using a crosslinking agent. The crosslinking agent is formulated to have at least three functional groups that are reactive with functional groups of the polyurethane or of the isocyanate-active prepolymer. A method of making the photochromic polyurethane laminate includes steps of causing the crosslinking.
1. A photochromic polyurethane laminate comprising:
a first resin layer;
a second resin layer; and
a crosslinked photochromic polyurethane layer disposed between the first and the second resin layers, the crosslinked photochromic polyurethane layer formed of a composition comprising;
a polyurethane;
an isocyanate prepolymer;
a crosslinking agent having functional groups that react with one of a hydroxyl group of the polyurethane or an isocyanate group of the isocyanate prepolymer, the crosslinking agent employed in the composition at a weight percent of less than one and greater than or equal to 0.04; and
at least one photochromic compound.
2. The photochromic polyurethane laminate according to claim 1 , wherein at least three functional groups of the crosslinking agent are reactive with hydroxyl groups in said polyurethane.
3. The photochromic polyurethane laminate according to claim 1 , wherein at least three functional groups of the crosslinking agent are reactive with isocyanate groups of the isocyanate prepolymer.
4. The photochromic polyurethane laminate according to claim 1 , wherein said crosslinking agent comprises a multifunctional alcohol having three or more functional hydroxyl groups.
5. The photochromic polyurethane laminate according to claim 1 , wherein said crosslinking agent comprises an oligomer having three or more functional hydroxyl groups.
6. The photochromic polyurethane laminate according to claim 1 , wherein the polyurethane is a thermoplastic polyurethane.
7. The photochromic polyurethane laminate according to claim 1 , wherein the polyurethane comprises a polymerized solution of a prepolymer and a chain extender.
8. The photochromic polyurethane laminate according to claim 1 , wherein said crosslinking agent is di(trimethylolpropane) or trimethylolpropane.
9. A photochromic polyurethane laminate comprising:
a crosslinked photochromic polyurethane layer prepared from a composition comprising:
a polyurethane;
an isocyanate prepolymer;
a crosslinking agent comprising a multifunctional alcohol having more than three functional hydroxyl groups; and
a photochromic agent;
a first resin layer attached to a first side of the crosslinked photochromic polyurethane layer; and
a second resin layer attached to a second side of the crosslinked photochromic polyurethane layer.
10. The photochromic polyurethane laminate according to claim 9 , wherein the polyurethane is formed from a polycaprolactone diol.
11. A photochromic polyurethane laminate comprising:
a crosslinked photochromic polyurethane layer prepared from a composition comprising:
a polyurethane;
an isocyanate prepolymer;
a crosslinking agent comprising an oligomer having three or more functional hydroxyl groups, the crosslinking agent employed in the composition at a weight percent of less than one and greater than or equal to 0.04; and
a photochromic agent;
a first resin layer attached to a first side of the crosslinked photochromic polyurethane layer; and
a second resin layer attached to a second side of the crosslinked photochromic polyurethane layer.
12. The photochromic polyurethane laminate according to claim 11 , wherein the polyurethane is formed from a polycaprolactone diol.