Brightness enhancing film comprising nanocomposite structure having improved crack resistance

Abstract

Microstructured films such as brightness enhancing films, polymerizable resin compositions comprising an organic component and surface modified nanoparticles, and surface modified nanoparticles are described. The microstructured film has a polymerized structure comprising the reaction product of the polymerizable resin composition (e.g. having a refractive index of at least 1.58). The cured nanocomposite (e.g. structure) can exhibit improved crack resistance. In some embodiments, the flexibility is expressed in terms of a cylindrical mandrel bend test property (e.g. a mandrel size to failure of less than 6 mm or a mandrel size to failure according to the equation D=1000(T/0.025−T) wherein T is the thickness in millimeters of a (e.g. preformed base layer). In other embodiments, the flexibility is expressed in terms of a tensile and elongation property (e.g. a tensile strength at break of at least 25 MPa and an elongation at break of at least 1.75%).

1 . A brightness enhancing film having a polymerized structure comprising the reaction product of polymerizable resin composition having a refractive index of at least 1.58 comprising an organic component having at least one di(meth)acrylate aromatic monomer and at least 10 wt-% of surface modified inorganic nanoparticles wherein the brightness enhancing film has a mandrel size to failure of less than 6 mm. 
     
     
         2 - 6 . (canceled) 
     
     
         7 . The brightness enhancing film according to  claim 1  wherein the polymerizable resin composition has a refractive index of at least 1.61. 
     
     
         8 . The brightness enhancing film according to  claim 1  wherein the polymerizable resin composition has a refractive index of at least 1.645. 
     
     
         9 . The brightness enhancing film according to  claim 1  wherein the organic component comprises at least one biphenyl monomer. 
     
     
         10 - 11 . (canceled) 
     
     
         12 . The brightness enhancing film according to  claim 9  wherein the one or more biphenyl monomers are present in an amount ranging from 25 wt-% to 75 wt-% of the organic component. 
     
     
         13 - 14 . (canceled) 
     
     
         15 . The brightness enhancing film according to  claim 9  wherein the biphenyl monomer comprises a (meth)acrylate group. 
     
     
         16 . The brightness enhancing film of  claim 15  wherein the biphenyl monomer has the general formula: 
       
         
           
           
               
               
           
         
         wherein R1 is H or CH 3 ;
 X is O or S; 
 n ranges from 0 to 10; and 
 L is an alkyl group having 1 to 5 carbon atoms, optionally substituted with hydroxy. 
 
       
     
     
         17 . The brightness enhancing film of  claim 15  wherein the biphenyl monomer has the general formula: 
       
         
           
           
               
               
           
         
         wherein R1 is H or CH 3 ;
 X is O or S; 
 Q is selected from —(C(CH 3 ) 2 —, —CH 2 , —C(O)—, —S(O)—, and —S(O) 2 —; 
 n ranges from 0 to 10; and 
 L is an alkyl group having 1 to 5 carbon atoms, optionally substituted with hydroxy. 
 
       
     
     
         18 - 22 . (canceled) 
     
     
         23 . The brightness enhancing film of  claim 1  wherein the di(meth)acrylate aromatic monomer comprises a major portion having the structure 
       
         
           
           
               
               
           
         
         wherein R1 is independently hydrogen or methyl, 
         R2 is independently H or Br, 
         Z is independently —C(CH 3 ) 2 —, —CH 2 —, —C(O)—, —S—, —S(O)—, or —S(O) 2 —, and 
         L is a linking group independently selected from linear and branched C 2 -C 12  alkyl groups wherein the carbon chain is optionally substituted with one or more oxygen group and/or the carbon atoms are optionally substituted with one or more hydroxyl groups. 
       
     
     
         24 . The brightness enhancing film according to  claim 1  wherein the organic component further comprises up to 25 wt-% of one or more monofunctional (meth)acrylate monomers having a refractive index lower than the biphenyl monomer. 
     
     
         25 . The brightness enhancing film of  claim 1  wherein the polymerizable resin comprises less than 5 wt-% of a crosslinker having at least three ethylenically unsaturated groups. 
     
     
         26 . (canceled) 
     
     
         27 . The brightness enhancing film of  claim 1  wherein the polymerizable resin composition is free of silane surface treatments. 
     
     
         28 . The brightness enhancing film according to  claim 1  wherein the inorganic nanoparticles comprise a first surface treatment having the general formula:
   CH 3 —[O—(CH 2 ) y ] x —X 2 —(CH 2 ) n —COOH   wherein X 2  is selected from the group consisting of —O—, —S—, —C(O)O— and —C(O)NH; n ranges from about 1-3; x ranges from about 1-10; and y ranges from about 1-4.   
     
     
         29 . The brightness enhancing film of  claim 28  wherein the first surface treatment is selected from the group consisting of 2-[2-(2-methoxyethoxy)ethoxy]acetic acid, 2-(2-methoxyethoxy)acetic acid, succinic acid mono-[2-(2-methoxy-ethoxy)-ethyl]ester, maleic acid mono-[2-(2-methoxy-ethoxy)-ethyl]ester, and glutaric acid mono-[2-(2-methoxy-ethoxy)-ethyl]ester, succinic acid mono-2-[2-(2-methoxyethoxy)ethoxy]ethyl ester, and mixtures thereof. 
     
     
         30 . The brightness enhancing film according to  claim 28  wherein the inorganic nanoparticles comprise a second surface treatment selected from the group consisting of succinic acid mono-(2-acryloyloxy-ethyl)ester, maleic acid mono-(2-acryloyloxy-ethyl)ester, and glutaric acid mono-(2-acryloyloxy-ethyl)ester, maleic acid mono-(4-acryloyloxy-butyl)ester, succinic acid mono-(4-acryloyloxy-butyl)ester, glutaric acid mono-(4-acryloyloxy-butyl)ester. 
     
     
         31 . The brightness enhancing film of  claim 1  wherein the amount of inorganic nanoparticles ranges from 40 wt-% to 60 wt-%. 
     
     
         32 . (canceled) 
     
     
         33 . The brightness enhancing film of  claim 1  wherein the inorganic nanoparticles are selected from the group consisting of zirconia, titania, and mixtures thereof. 
     
     
         34 . The brightness enhancing film of  claim 1  wherein the inorganic nanoparticle consist of zirconia. 
     
     
         35 . A polymerizable resin composition having a refractive index of at least 1.58 comprising an organic component and at least 10 wt-% of surface modified inorganic nanoparticles wherein a cured film of the polymerizable resin composition has a tensile strength at break of at least 25 MPa and an elongation at break of at least 2%. 
     
     
         36 - 46 . (canceled) 
     
     
         47 . Inorganic nanoparticles surface modified with
 a first surface treatment comprising at least one monocarboxylic acid having a non-reactive compatibilizing group, and   a second surface treatment comprising at least one non-volatile monocarboxylic acid having a copolymerizable group that reacts with the organic component;   
       wherein the nanoparticles comprise the second surface treatment in a stoichiometric amount than the first surface treatment.