Optical member, polyimide, method for manufacturing optical member, and method for producing polyimide

Abstract

There is provided an optical member that can retain a high antireflection effect on a substrate for a long time. The optical member includes a laminated body that can reduce the reflection of light formed on a substrate surface, wherein at least one layer of the laminated body is a polyimide layer containing a polyimide film, and the polyimide contains a repeating unit represented by the following general formula (1), and a 1,4-cyclohexylene group in the main chain of R 2 in the general formula (1) contains 90% by mole or more of a trans-1,4-cyclohexylene group: wherein R 1 denotes a tetravalent organic group, and R 2 denotes a divalent organic group having one or two or more 1,4-cyclohexylene groups in the main chain.

1 . A method for manufacturing an optical member including a laminated body that can reduce the reflection of light formed on a substrate surface, comprising:
 1) purifying a diamine represented by the following general formula (3) such that a 1,4-cyclohexylene group in the main chain of R 2  in the general formula (3) contains 90% by mole or more of a trans-1,4-cyclohexylene group;
   [Chem. 2] 
   H 2 N—R 2 —NH 2   (3)
 
   wherein R 2  denotes a divalent organic group having one or two or more 1,4-cyclohexylene groups in the main chain,   2) producing a polyimide containing a repeating unit represented by the following general formula (1) by the reaction of the purified diamine with an acid dianhydride represented by the following general formula (4) in a solvent;   
       
         
           
           
               
               
           
         
         wherein R 1  denotes a tetravalent organic group, 
       
       
         
           
           
               
               
           
         
         wherein R 1  and R 2  are as described above, 
         3) applying a solution containing the polyimide to the substrate or a thin film formed on the substrate; and 
         4) drying and/or firing the applied solution containing the polyimide at 100° C. or more and 250° C. or less to form a polyimide layer. 
       
     
     
         2 . The method for manufacturing an optical member according to  claim 1 , further comprising:
 5) applying a precursor sol of aluminum oxide to the outermost surface of the laminated body;   6) drying and/or firing the applied precursor sol of aluminum oxide at 100° C. or more and 250° C. or less to form an aluminum oxide film; and   7) immersing the aluminum oxide film in hot water to form a textured structure formed of plate crystals containing 70% by mole or more of aluminum oxide.   
     
     
         3 . A polyimide having a repeating unit represented by the following general formula (1), wherein 90% by mole or more of a 1,4-cyclohexylene group in the general formula (1) has a trans form: 
       
         
           
           
               
               
           
         
         wherein R 1  denotes a tetravalent organic group, and R 2  denotes a divalent organic group having one or two or more 1,4-cyclohexylene groups in the main chain. 
       
     
     
         4 . The polyimide according to  claim 3 , further comprising a repeating unit represented by the following general formula (2): 
       
         
           
           
               
               
           
         
         wherein R 1  denotes a tetravalent organic group, n denotes an integer in the range of 0 to 2, R 3  to R 10  independently denote a hydrogen atom, a halogen atom, a phenyl group, or a linear or cyclic alkyl, alkenyl, or alkynyl group having 1 to 6 carbon atoms, and R 11  and R 12  independently denote a hydrogen atom or a linear or cyclic alkyl group having 1 to 6 carbon atoms. 
       
     
     
         5 . The polyimide according to  claim 3 , further comprising a repeating unit represented by the following general formula (5): 
       
         
           
           
               
               
           
         
         wherein R 1  denotes a tetravalent organic group, R 11  to R 14  independently denote a hydrogen atom, a phenyl group, or an alkyl, alkenyl, or alkynyl group having 1 to 4 carbon atoms, R 11  to R 14  may be the same or different, R 15  and R 16  independently denote a phenylene group or an alkylene group having 1 to 4 carbon atoms, R 15  and R 16  may be the same or different, and n denotes an integer in the range of 0 to 6. 
       
     
     
         6 . A method for producing a polyimide, comprising:
 purifying a diamine represented by the following general formula (3) such that 90% by mole or more of a 1,4-cyclohexylene group in the general formula (3) has a trans form;
   [Chem. 6] 
   H 2 N—R 2 —NH 2   (3)
 
   wherein R 2  denotes a divalent organic group having one or two or more 1,4-cyclohexylene groups in the main chain,   producing a polyimide precursor by the reaction between the diamine represented by the general formula (3) purified and an acid dianhydride represented by the following general formula (4) in a solvent;   
       
         
           
           
               
               
           
         
         wherein R 1  denotes a tetravalent organic group, 
         producing a polyimide by the imidization of the polyimide precursor in a solvent; and 
         isolating the polyimide by removing the solvent. 
       
     
     
         7 . The method for producing a polyimide according to  claim 6 , wherein
 the polyimide precursor is produced by the reaction between the diamine represented by the general formula (3) purified, a diamine represented by the following general formula (12), and the acid dianhydride represented by the general formula (4):   
       
         
           
           
               
               
           
         
         wherein R 11  to R 14  independently denote a hydrogen atom, a phenyl group, or an alkyl, alkenyl, or alkynyl group having 1 to 4 carbon atoms, R 11  to R 14  may be the same or different, R 15  and R 16  independently denote a phenylene group or an alkylene group having 1 to 4 carbon atoms, R 15  and R 16  may be the same or different, and n denotes an integer in the range of 0 to 6.