Isotropic layer of multilayer optical film comprising birefringent thermoplastic polymer

摘要

Multilayer optical films are described comprising at least one first optical layer comprising a birefringent thermoplastic polymer having an in-plane birefringence of at least 0.15 at 632.8 nm; and at least one second optical layer having an in-plane birefringence of less than 0.040 at 632.8 nm. The second optical layer comprises a copolymerized blend of at least one birefringent thermoplastic polymer and at least one second thermoplastic polymer.

主权项

1. A multilayer optical film comprising
a) at least one first optical layer consisting of a birefringent polyethylene naphthalate thermoplastic polymer, comprising at least 95 mol % of naphthalate subunits, based on a 100 mol % carboxylate subunits and greater than 95% of ethylene glycol subunits, based on 100% glycol subunits, the first optical layer having an in-plane birefringence of at least 0.15 at 632.8 nm; and (b) at least one second optical layer having an in-plane birefringence of less than 0.040 at 632.8 nm; wherein the second optical layer consists of a copolymerized blend consisting of 40 to 60 mol % of the birefringent polyethylene naphthalate thermoplastic polymer of the first layer and a polyethylene terephthalate thermoplastic polymer comprising at least 95 mol % of terephthalate subunits, based on a 100 mol % carboxylate subunits and greater than 95% of ethylene glycol subunits, based on 100% glycol subunits.