Diamine compound having dendron side chain and liquid crystal aligning agent using same

Abstract

Disclosed herein is a novel functional diamine compound having a dendron structure, polyamic acid which is produced using functional diamine, aromatic cyclic diamine, aliphatic cyclic acid dianhydride, and aromatic cyclic acid dianhydride, polyimide which is produced by imidizing polyamic acid, and an LC alignment film produced using polyimide. Even if the diamine compound is used in a small amount, it is possible to realize a high pretilt angle, thus the pretilt angle is easily controlled. Therefore, it can be used to produce an LC alignment film using a twisted nematic (TN) mode, in which the pretilt angle of liquid crystal is low, and a vertically aligned (VA) mode, which requires a high pretilt angle of about 90°.

1 . A diamine compound which has a structure of the following Formula 1 and a dendron side chain  
       
         
           
           
               
               
           
         
         wherein, A and A′ are each independently a single bond, or are selected from a group consisting of —O—, —COO—, —OCO—, and —NHCO—; B is a single bond or a benzene ring having an equivalence of 2 
         
           
             
             
                 
                 
             
           
         
         m is 1 to 3; n is 2 or 3; G is a single bond (when m is 1), a benzene ring having an equivalence of 3 
         
           
             
             
                 
                 
             
           
         
         when m is 2), or a benzene ring having an equivalence of 4 
         
           
             
             
                 
                 
             
           
         
         when m is 3); and R is a linear, branched, or cyclic alkyl or fluoroalkyl group having 1 to 30 carbons.  
       
     
     
         2 . The diamine compound as set forth in  claim 1 , wherein the diamine compound has a structure of the following Formula 2 or 3 
       
         
           
           
               
               
           
         
         
           
           
               
               
           
         
       
     
     
         3 . A polyamic acid, comprising: 
 the diamine compound according to  claim 1;     aliphatic cyclic acid dianhydride;    aromatic cyclic acid dianhydride; and    optionally aromatic cyclic diamine,    wherein, the diamine compound, the aliphatic cyclic acid dianhydride, the aromatic cyclic acid dianhydride, and optionally the aromatic cyclic diamine are copolymerized, thereby producing the polyamic acid.    
     
     
         4 . The polyamic acid as set forth in  claim 3 , wherein the polyamic acid is expressed by the following Formula 4 
       
         
           
           
               
               
           
         
         wherein, X includes one or more selected from functional groups expressed by the following Formula 5, Y includes one or more selected from functional groups expressed by the following Formula 6, Z includes one or more functional groups selected from functional groups expressed by the following Formula 7 or 8, and Z′ is a functional group of the following Formula 9 
         
           
             
             
                 
                 
             
           
         
         wherein, X 1 , X 2 , X 3 , and X 4  are each independently substituents selected from the group consisting of —CH 3 , —F, and —H  
         
           
             
             
                 
                 
             
           
         
         wherein, n is an integer from 1 to 10 
         
           
             
             
                 
                 
             
           
         
         wherein, A and A′ are each independently a single bond, or are selected from the group consisting of —O—, —COO—, —OCO—, and —NHCO—; B is a single bond or a benzene ring having an equivalence of 2 
         
           
             
             
                 
                 
             
           
         
         m is 1 to 3; n is 2 or 3; G is a single bond (when m is 1), a benzene ring having an equivalence of 3 
         
           
             
             
                 
                 
             
           
         
         when m is 2), or a benzene ring having an equivalence of 4 
         
           
             
             
                 
                 
             
           
         
         when m is 3); and R is a linear, branched, or cyclic alkyl or fluoroalkyl group having 1 to 30 carbons.  
       
     
     
         5 . The polyamic acid as set forth in  claim 3 , wherein an average molecular weight of the polyamic acid is 5000-500,000 g/mol.  
     
     
         6 . The polyamic acid as set forth in  claim 3 , wherein content of the diamine of Formula 1 is 0.1-100 mol % and content of the aromatic cyclic diamine is 0-99.9 mol % based on total diamine monomers contained in the polyamic acid.  
     
     
         7 . The polyamic acid as set forth in  claim 3 , wherein content of the aliphatic cyclic acid dianhydride is 5-90 mol % and content of the aromatic cyclic acid dianhydride is 10-95 mol % based on total acid dianhydride contained in the polyamic acid.  
     
     
         8 . A polyimide compound produced by partially or totally imidizing the polyamic acid according to  claim 3 .  
     
     
         9 . A liquid crystal alignment film produced by totally or partially imidizing a substance selected from the group consisting of the polyamic acid according to  claim 3 , the polyimide according to  claim 8 , and a mixture of the polyamic acid according to  claim 3  and the polyimide according to  claim 8 .  
     
     
         10 . A liquid crystal display comprising the liquid crystal alignment film according to  claim 9.