Benzyl (meth)acrylate monomers suitable for microstructured optical films
Presently described are optical films comprising a polymerized (e.g. microstructured) surface that comprises the reaction product of a polymerizable resin composition and polymerizable resin compositions that comprise nanoparticles; at least one first monomer comprising at least two (meth)acrylate groups; and at least one second (meth)acrylate monomer having following the structure (I); wherein at least one R1 comprises an aromatic substituent, t is an integer from 1 to 4, and R2 is hydrogen or methyl.
1. An optical film comprising a preformed polymeric film base layer and a polymerized microstructured optical layer, the polymerized microstructured optical layer comprising a linear array of regular prisms, the prisms having apex angles ranging from 80° to 100° and peaks with a spacing ranging from 5 to 300 microns wherein the polymerized microstructured optical layer comprises the reaction product of a polymerizable resin composition comprising
zirconia nanoparticles wherein the amount of zirconia nanoparticles ranges from 10 wt-% to 70 wt-%;
5 wt-% to 30 wt-% of one or more first monomers comprising at least two (meth)acrylate groups and two aromatic rings selected from bisphenol or biphenyl (meth)acrylate monomer; and mono(meth)acrylate monomer(s) consisting of one or more second acrylate monomers having the structure
wherein R1 is
t is 1, and
R2 is hydrogen; and wherein the polymerizable resin comprises at least 10 wt.-% of the second acrylate monomer(s).
2. The optical film of claim 1 wherein the optical film is a brightness enhancing film.
3. The optical film of claim 2 wherein the brightness enhancing film has a single sheet relative gain of at least 1.75.
4. The optical film of claim 1 wherein the polymerizable resin composition is non-halogenated.
5. The optical film of claim 1 wherein the polymerizable resin comprises up to 15 wt-% of one or more first monomers comprising at least two (meth)acrylate groups.
6. The optical film of claim 1 wherein the first monomer comprising at least two (meth)acrylate groups has a molecular weight of at least 350 g/mole.
7. The optical film of claim 1 wherein the second monomer has a refractive index of at least 1.54.
8. The optical film of claim 1 wherein the second monomer has a viscosity of less than 100 cps at 25° C.
9. The optical film of claim 1 wherein the amount of zirconia nanoparticles is no greater than 60 wt-% of the polymerizable resin composition.
10. The optical film of claim 1 wherein the polymerizable resin comprises 30 wt-% to 60 wt-% zirconia nanoparticles.