Optical film and method of preparing optical film

Abstract

A method of preparing an optical film, preparing a coating composition including an amic acid-containing polymer represented by Chemical Formula 1 and at least one polymerization aid selected from an alkyl phosphite, an aryl phosphite, an alkyl phosphate, and an aryl phosphate; providing the coating composition on a substrate to form a coating layer; and applying heat to the coating layer to prepare a cured film: wherein, in Chemical Formula 1, are the same or different in each repeating unit, and are each independently at least one selected from an aromatic organic group, an aliphatic organic group, and an alicyclic organic group, and 0≦x≦1.

What is claimed is: 
     
         1 . A composition for preparing a film, the composition comprising:
 an imide and amic acid-containing random copolymer represented by Chemical Formula 1; and   at least one polymerization aid selected from an alkyl phosphite, an aryl phosphite, an alkyl phosphate, and an aryl phosphate:   
       
         
           
           
               
               
           
         
         wherein, in Chemical Formula 1, 
       
       
         
           
           
               
               
           
         
       
       are the same or different in each repeating unit, and are each independently selected from at least one of an aromatic organic group, an aliphatic organic group, and an alicyclic organic group, and
   0<x<1. 
 
     
     
         2 . The composition according to  claim 1 , wherein the composition further comprises a chemical imidizing agent selected from an alkyl acid anhydride and an aryl acid anhydride. 
     
     
         3 . The composition according to  claim 1 , wherein the polymerization aid is included in an amount of about 0.01 to about 100 mol % based on the total moles of amic acid in the imide and amic acid-containing random copolymer represented by Chemical Formula 1. 
     
     
         4 . The composition according to  claim 1 , wherein the polymerization aid is included in an amount of about 10 to about 90 mol % based on the total moles of amic acid in the imide and amic acid-containing random copolymer represented by Chemical Formula 1. 
     
     
         5 . The composition according to  claim 2 , wherein the chemical imidizing agent is included in an amount of about 0.01 to about 100 mol % based on the total moles of amic acid in the imide and amic acid-containing random copolymer represented by Chemical Formula 1. 
     
     
         6 . The composition according to  claim 1 , wherein the 
       
         
           
           
               
               
           
         
       
       of Chemical Formula 1 are the same or different in each repeating unit, and are each independently selected from at least one of a substituted or unsubstituted C4 to C20 carbocyclic group, a substituted or unsubstituted C6 to C20 monocyclic aromatic group, a substituted or unsubstituted C6 to C20 condensed polycyclic aromatic group, and a substituted or unsubstituted C6 to C20 non-condensed polycyclic aromatic group linked to each other by a single bond or a linker selected from a substituted or unsubstituted alkylene group, a substituted or unsubstituted cycloalkylene group, a substituted or unsubstituted heterocycloalkylene group, a substituted or unsubstituted arylene group, a substituted or unsubstituted heteroarylene group, —SO 2 —, —C(═O)—, and —O—. 
     
     
         7 . The composition according to  claim 1 , wherein, in Chemical Formula 1, 0.05<x≦0.9. 
     
     
         8 . The composition according to  claim 1 , wherein, in Chemical Formula 1, 0.2<x≦0.7. 
     
     
         9 . The composition according to  claim 1 , wherein the polymerization aid is triisopropyl phosphite. 
     
     
         10 . The composition according to  claim 2 , wherein the chemical imidizing agent is acetic anhydride. 
     
     
         11 . The composition according to  claim 1 , wherein the imide and amic acid-containing random copolymer represented by Chemical Formula 1 is a reaction product of a diamine and a dianhydride, wherein the diamine is selected from at least one of the following chemical formulae: 
       
         
           
           
               
               
           
         
         wherein, in the chemical formulae, 
         R 32  to R 52  are each independently a halogen, a nitro group, a substituted or unsubstituted C1 to C15 alkyl group, a substituted or unsubstituted C1 to C15 alkoxy group, a substituted or unsubstituted C1 to C15 fluoroalkyl group, a substituted or unsubstituted C3 to C15 cycloalkyl group, a substituted or unsubstituted C3 to C15 heterocycloalkyl group, a substituted or unsubstituted C3 to C15 cycloalkoxy group, a substituted or unsubstituted C6 to C15 aryl group, a substituted or unsubstituted C6 to C15 aryloxy group, or a substituted or unsubstituted C2 to C15 heteroaryl group, 
         X 2  to X 12  are each independently a single bond, a substituted or unsubstituted C1 to C10 alkylene group, a substituted or unsubstituted C1 to C10 cycloalkylene group, a substituted or unsubstituted C5 to C40 heterocycloalkylene group, a substituted or unsubstituted C6 to C15 arylene group, a substituted or unsubstituted C3 to C40 heteroarylene group, —SO 2 —, —O—, —C(═O)—, or a combination thereof, 
         n35 to n37 and n40 to n49 are integers ranging from 0 to 4, and 
         n38 and n39 are integers ranging from 0 to 3. 
       
     
     
         12 . The composition according to  claim 11 , wherein the diamine is selected from at least one of the compounds represented by the following chemical formulae: 
       
         
           
           
               
               
           
         
         
           
           
               
               
           
         
         
           
           
               
               
           
         
       
     
     
         13 . The composition according to  claim 11 , wherein the dianhydride is represented by Chemical Formula 2: 
       
         
           
           
               
               
           
         
         wherein, in Chemical Formula 2, 
         Cy is a substituted or unsubstituted C4 to C20 carbocyclic group, a substituted or unsubstituted C6 to C20 monocyclic aromatic group, a substituted or unsubstituted C6 to C20 condensed polycyclic aromatic group, or a substituted or unsubstituted C6 to C20 non-condensed polycyclic aromatic group linked to each other by a single bond or a linker selected from a substituted or unsubstituted alkylene group, a substituted or unsubstituted cycloalkylene group, a substituted or unsubstituted heterocycloalkylene group, a substituted or unsubstituted arylene group, a substituted or unsubstituted heteroarylene group, —SO 2 —, —C(═)—, and —O—. 
       
     
     
         14 . The composition according to  claim 13 , wherein the dianhydride is selected from at least one of 3,3′,4,4′-biphenyl tetracarboxylic dianhydride, bicyclo[2.2.2]oct-7-ene-2,3,5,6-tetracarboxylic dianhydride, 3,3′,4,4′-biphenylsulfone tetracarboxylic dianhydride, 4,4′-(hexafluoroisopropylidene)diphthalic anhydride, 4,4′-oxydiphthalic anhydride, pyromellitic dianhydride, and 4-(2,5-dioxotetrahydrofuran-3-yl)-1,2,3,4-tetrahydronaphthalene-1,2-dicarboxylic anhydride. 
     
     
         15 . The composition according to  claim 11 , wherein the diamine comprises 2,2′-bis(trifluoromethyl)benzidine, and the dianhydride comprises 3,3′,4,4′-biphenyltetracarboxylic dianhydride and 4,4′-(hexafluoroisopropylidene) diphthalic anhydride. 
     
     
         16 . The composition according to  claim 15 , wherein the polymerization aid is triisopropyl phosphite. 
     
     
         17 . The composition according to  claim 15 , wherein the composition further comprises a chemical imidizing agent selected from an alkyl acid anhydride and an aryl acid anhydride. 
     
     
         18 . A film prepared from the composition according to  claim 1 . 
     
     
         19 . The film according to  claim 18 , wherein the film has an increased toughness compared with a film prepared from a composition comprising an imide and amic acid-containing random copolymer represented by Chemical Formula 1, but not comprising a polymerization aid selected from an alkyl phosphite, an aryl phosphite, an alkyl phosphate, and an aryl phosphate: 
       Chemical Formula 1 
       
         
           
           
               
               
           
         
         wherein, in Chemical Formula 1, 
       
       
         
           
           
               
               
           
         
       
       are the same or different in each repeating unit, and are each independently selected from at least one of an aromatic organic group, an aliphatic organic group, and an alicyclic organic group, and
   0<x<1. 
 
     
     
         20 . The film according to  claim 18 , wherein the film has a yellow index of about 0 to about 6.