Curable fluoropolymer, curable resin composition containing the same, and antireflection film

Abstract

There are provided a curable fluorine-containing polymer which can realize a high hardness by photo-curing while maintaining a low refractive index, an antireflection film possessing improved scratch resistance and abrasion resistance while maintaining a reflection reducing effect, and an antireflection-treated article provided with such an antireflection film. The curable fluorine-containing polymer has a number average molecular weight of from 500 to 1,000,000 and is represented by the formula (1): AM  (1) in which the structural unit M is a structural unit derived from a fluorine-containing ethylenic monomer and represented by the formula (M): wherein X 1 and X 2 are the same or different and each is H or F; X 3 is H, F, CH 3 or CF 3 ; X 4 and X 5 are the same or different and each is H, F or CF 3 ; Rf is an organic group in which 1 to 3 of Y 1 (Y 1 is a monovalent organic group having 2 to 10 carbon atoms and an ethylenic carbon-carbon double bond at its end) are bonded to a fluorine-containing alkyl group having 1 to 40 carbon atoms or a fluorine-containing alkyl group having 2 to 100 carbon atoms and ether bond; a is 0 or an integer of from 1 to 3; b and c are the same or different and each is 0 or 1, the structural unit A is a structural unit derived from a monomer copolymerizable with the fluorine-containing ethylenic monomer represented by the formula (M), and the structural unit M and the structural unit A are contained in amounts of from 0.1 to 100 % by mole and from 0 to 99.9 % by mole, respectively.

1 . A curable fluorine-containing polymer which has a number average molecular weight of from 500 to 1,000,000 and is represented by the formula (1):  
       MA  (1)  
       in which the structural unit M is a structural unit derived from fluorine-containing ethylenic monomer and represented by the formula (M):  
       
         
           
           
               
               
           
         
       
       wherein X 1  and X 2  are the same or different and each is H or F; X 3  is H, F, CH 3  or CF 3 ; X 4  and X 5  are the same or different and each is H, F or CF 3 ; Rf is an organic group in which 1 to 3 of Y 1  (Y 1  is a monovalent organic group having 2 to 10 carbon atoms and an ethylenic carbon-carbon double bond at its end) are bonded to a fluorine-containing alkyl group having 1 to 40 carbon atoms or a fluorine-containing alkyl group having 2 to 100 carbon atoms and ether bond; a is 0 or an integer of from 1 to 3; b and c are the same or different and each is 0 or 1,  
       the structural unit A is a structural unit derived from monomer copolymerizable with the fluorine-containing ethylenic monomer represented by the formula (M),  
       said polymer comprises from 0.1 to 100% by mole of the structural unit M and from 0 to 99.9% by mole of the structural unit A.  
     
     
         2 . A curable fluorine-containing polymer which has a number average molecular weight of from 500 to 1,000,000 and is represented by the formula (1-1):  
       MA1A2  (1-1)  
       in which the structural unit M is the same structural unit as said formula (M),  
       the structural unit A1 is a structural unit represented by the formula (A1):  
       
         
           
           
               
               
           
         
       
       wherein X 11 , X 12  and X 13  are the same or different and each is H or F; X 14  is H, F or CF 3 ; h is 0, 1 or 2; i is 0 or 1; Rf 4  is a fluorine-containing alkylene group having 1 to 40 carbon atoms or a fluorine-containing alkylene group having 2 to 100 carbon atoms and ether bond; Z 1  is selected from —OH, —CH 2 OH, —COOH, carboxylic acid derivative, —SO 3 H, sulfonic acid derivative, epoxy group and cyano group,  
       the structural unit A2 is a structural unit represented by the formula (A2):  
       
         
           
           
               
               
           
         
       
       wherein X 15 , X 16  and X 18  are H or F; X 17  is H, F or CF 3 ; h1, i1 and j are 0 or 1; Z 2  is H, F or Cl; Rf 5  is a fluorine-containing alkylene group having 1 to 20 carbon atoms or a fluorine-containing alkylene group having 2 to 100 carbon atoms and ether bond,  
       said polymer comprises from 0.1 to 90% by mole of the structural unit M, from 0 to 99.9% by mole of the structural unit Al and from 0 to 99.9% by mole of the structural unit A2 and contains from 10 to 99.9% by mole of A1+A2.  
     
     
         3 . The curable fluorine-containing polymer of  claim 1  or  2 , wherein at least one Y 1  is bonded to an end of Rf.  
     
     
         4 . The curable fluorine-containing polymer of any of  claims 1  to  3 , wherein in the formula (1) or (1-1), the structural unit M is a structural unit M1 derived from fluorine-containing ethylenic monomer and represented by the formula (M1):  
       
         
           
           
               
               
           
         
       
       wherein X 1  and X 2  are the same or different and each is H or F; X 3  is H, F, CH 3  or CF 3 ; X 4  and X 5  are the same or different and each is H, F or CF 3 ; Rf is an organic group in which 1 to 3 of Y 1  (Y 1  is a monovalent organic group having 2 to 10 carbon atoms and an ethylenic carbon-carbon double bond at its end) are bonded to a fluorine-containing alkyl group having 1 to 40 carbon atoms or a fluorine-containing alkyl group having 2 to 100 carbon atoms and ether bond; a is 0 or an integer of from 1 to 3; c is 0 or 1.  
     
     
         5 . The curable fluorine-containing polymer of any of  claims 1  to  3 , wherein in the formula (1) or (1-1), the structural unit M is a structural unit M2 derived from fluorine-containing ethylenic monomer and represented by the formula (M2):  
       
         
           
           
               
               
           
         
       
       wherein Rf is an organic group in which 1 to 3 of Y 1  (Y 1  is a monovalent organic group having 2 to 10 carbon atoms and an ethylenic carbon-carbon double bond at its end) are bonded to a fluorine-containing alkyl group having 1 to 40 carbon atoms or a fluorine-containing alkyl group having 2 to 100 carbon atoms and ether bond.  
     
     
         6 . The curable fluorine-containing polymer of any of  claims 1  to  3 , wherein in the formula (1) or (1-1), the structural unit M is a structural unit M3 derived from fluorine-containing ethylenic monomer and represented by the formula (M3):  
       
         
           
           
               
               
           
         
       
       wherein Rf is an organic group in which 1 to 3 of Y 1  (Y 1  is a monovalent organic group having 2 to 10 carbon atoms and an ethylenic carbon-carbon double bond at its end) are bonded to a fluorine-containing alkyl group having 1 to 40 carbon atoms or a fluorine-containing alkyl group having 2 to 100 carbon atoms and ether bond.  
     
     
         7 . The curable fluorine-containing polymer of any of  claims 1  to  6 , wherein Y 1  is an organic group represented by the formula:  
       O d C═O) e —Y 2    
       wherein Y 2  is an alkenyl group or fluorine-containing alkenyl group having 2 to 5 carbon atoms and an ethylenic carbon-carbon double bond at an end thereof; d and e are the same or different and each is 0 or 1.  
     
     
         8 . The curable fluorine-containing polymer of any of  claims 1  to  6 , wherein Y 1  is represented by the formula:  
       —O(C═O)CX 6 ═CX 7 X 8    
       wherein X 6  is H, F, CH 3  or CF 3 ; X 7  and X 8  are the same or different and each is H or F.  
     
     
         9 . The curable fluorine-containing polymer of any of  claims 2  to  8 , wherein in the formula (1-1), the structural unit (A1) is represented by the formula (A1-1):  
       
         
           
           
               
               
           
         
       
       wherein Rf 4  and Z 1  are as defined in the formula (A1).  
     
     
         10 . The curable fluorine-containing polymer of any of  claims 2  to  8 , wherein in the formula (1-1), the structural unit (A1) is represented by the formula (A1-2):  
       
         
           
           
               
               
           
         
       
       wherein Rf 4  and Z 1  are as defined in the formula (A1).  
     
     
         11 . The curable fluorine-containing polymer of any of  claims 2  to  10 , wherein in the formula (1-1), the structural unit (A2) is a structural unit derived from at least one monomer selected from tetrafluoroethylene, vinylidene fluoride, chlorotrifluoroethylene and hexafluoropropylene.  
     
     
         12 . The curable fluorine-containing polymer of any of  claims 2  to  10 , wherein the polymer of the formula (1-1) comprises from 10 to 80% by mole of the structural unit M, from 1 to 60% by mole of the structural unit A1 and from 20 to 85% by mole of the structural unit A2 and contains from 20 to 90% by mole of A1+A2.  
     
     
         13 . The curable fluorine-containing polymer of any of  claims 1  to  12 , which has a refractive index of not more than 1.40.  
     
     
         14 . The curable fluorine-containing polymer of any of claims  1  to  13 , which is soluble in at least one solvent selected from the group consisting of ketone solvents, acetic acid ester solvents, alcohol solvents and aromatic hydrocarbon solvents.  
     
     
         15 . A process for preparing a curable fluorine-containing polymer having a number average molecular weight of from 500 to 1,000,000, which is characterized by comprising: 
 esterifying a fluorine-containing polymer having hydroxyl and represented by the formula (2)    NB  (2)    in which the structural unit N is a structural unit having hydroxyl and derived from a fluorine-containing ethylenic monomer and is represented by the formula (N):                          wherein X 1  and X 2  are the same or different and each is H or F; X 3  is H, F, CH 3  or CF 3 ; X 4  and X 5  are the same or different and each is H, F or CF 3 ; Rf 1  is an organic group in which 1 to 3 of Y 5  (Y 5  is hydroxyl or a monovalent organic group having 1 to 10 carbon atoms and hydroxyl) are bonded to a fluorine-containing alkyl group having 1 to 40 carbon atoms or a fluorine-containing alkyl group having 2 to 100 carbon atoms and ether bond; a is 0 or an integer of from 1 to 3; b and c are the same or different and each is 0 or 1,    the structural unit (B) is a structural unit derived from monomer copolymerizable with the fluorine-containing ethylenic monomer having hydroxyl and represented by the formula (N), and    the structural unit N and the structural unit B are contained in amounts of from 0.1 to 100% by mole and from 0 to 99.9% by mole, respectively, with an unsaturated carboxylic acid or its derivative having 3 to 10 carbon atoms (a total number of carbon atoms including carbon atoms of Ys is from 3 to 10) and represented by the formula:    HOOCR 1  f CX 6 ═CX 7 X 8      wherein R 1  is a divalent organic group which has 1 to 7 carbon atoms and may be substituted with fluorine atom; X 6  is H, F, CH 3  or CF 3 ; X 7  and X 8  are the same or different and each is H or F; f is 0 or 1,    said curable fluorine-containing polymer is represented by the formula (1a):    M4A  (1a)    in which the structural unit M4 is a structural unit derived from a fluorine-containing ethylenic monomer and represented by the formula (M4):                          wherein X 1  and X 2  are the same or different and each is H or F; X 3  is H, F, CH 3  or CF 3 ; X 4  and X 5  are the same or different and each is H, F or CF 3 ; Rf 2  is an organic group in which 1 to 3 of Y 6  having 3 to 10 carbon atoms and represented by the formula:    R 2  g O(C═OR 1  f CX 6 ═CX 7 X 8      wherein R 1 , X 6 , X 7 , X 8  and f are as defined above; R 2  is a divalent organic group which has 1 to 7 carbon atoms and may be substituted with fluorine atom; g is 0 or 1, are bonded to a fluorine-containing alkyl group having 1 to 40 carbon atoms or a fluorine-containing alkyl group having 2 to 100 carbon atoms and ether bond; a is 0 or an integer of from 1 to 3; b and c are the same or different and each is 0 or 1,    the structural unit A is a structural unit derived from monomer copolymerizable with the fluorine-containing ethylenic monomer represented by the formula (M4),    and the structural unit M4 and the structural unit A are contained in amounts of from 0.1 to 100% by mole and from 0 to 99.9% by mole, respectively.    
     
     
         16 . A cured article which is obtained by photo-curing a curable fluorine-containing resin composition comprising: 
 (a) the curable fluorine-containing polymer of any of  claims 1  to  14 , and    (b) a curing initiator which initiates curing with active energy.    
     
     
         17 . A fluorine-containing resin composition for coating which comprises: 
 (a) the curable fluorine-containing polymer of any of  claims 1  to  14 ,    (b) a curing initiator which initiates curing with active energy, and    (c) a solvent.    
     
     
         18 . The fluorine-containing resin composition for coating of  claim 17 , wherein the solvent (c) is at least one selected from the group consisting of ketone solvents, acetic acid ester solvents, alcohol solvents and aromatic hydrocarbon solvents.  
     
     
         19 . A cured film which is obtained by photo-curing a coating film formed by applying the fluorine-containing resin composition for coating of  claim 17  or  18 .  
     
     
         20 . An antireflection film which is a cured film of a fluorine-containing prepolymer, wherein said fluorine-containing prepolymer has: 
 (i) a carbon-carbon unsaturated bond at an end of its side chain, and    (ii) a refractive index of not more than 1.40,    and a thickness of the cured film is from 0.03 to 0.5 μm.    
     
     
         21 . An antireflection film which is a cured film obtained by photo-curing a coating film formed by coating a composition for coating which comprises: 
 (d) the prepolymer of  claim 20 ,    (e) a curing initiator which initiates curing with active energy, and    (f) a solvent,    in which a thickness of said cured film is from 0.03 to 0.5 μm.    
     
     
         22 . An antireflection film which is a cured film obtained by photo-curing a coating film formed by coating a composition for coating which comprises: 
 (d) the prepolymer of  claim 20 ,    (e) a curing initiator which initiates curing with active energy,    (f) a solvent, and    (g) a curing agent    in which a thickness of said cured film is from 0.03 to 0.5 μm.    
     
     
         23 . The antireflection film of  claim 21  or  22 , wherein the solvent (f) is at least one selected from the group consisting of ketone solvents, acetic acid ester solvents, alcohol solvents and aromatic hydrocarbon solvents.  
     
     
         24 . The antireflection film of any of  claims 20  to  23 , wherein the carbon-carbon unsaturated bond at an end of the fluorine-containing prepolymer is an ethylenic carbon-carbon double bond.  
     
     
         25 . The antireflection film of  claim 24 , wherein the carbon-carbon unsaturated bond at an end of the fluorine-containing prepolymer is a radically polymerizable carbon-carbon double bond.  
     
     
         26 . The antireflection film of any of  claims 20  to  23 , wherein the fluorine-containing prepolymer is at least one of the curable fluorine-containing polymers of  claims 1  to  14 .  
     
     
         27 . The antireflection film of any of  claims 22  to  26 , wherein the curing agent (g) is at least one selected from polyfunctional acrylates obtained by replacing, with acrylate groups, two or more hydroxyl groups of polyalcohols having a fluorine-containing alkyl group which may have an ether bond or a fluorine-containing alkylene group which may have an ether bond; polyfunctional methacrylates obtained by replacing, with methacrylate groups, two or more hydroxyl groups of polyalcohols having a fluorine-containing alkyl group which may have an ether bond or a fluorine-containing alkylene group which may have an ether bond; and polyfunctional α-fluoroacrylates obtained by replacing, with α-fluoroacrylate groups, two or more hydroxyl groups of polyalcohols having a fluorine-containing alkyl group which may have an ether bond or a fluorine-containing alkylene group which may have an ether bond.  
     
     
         28 . The antireflection film of  claim 27 , wherein the curing agent (g) is at least one of polyfunctional α-fluoroacrylates.  
     
     
         29 . The antireflection film of any of  claims 20  to  28 , wherein a refractive index of the cured film is not more than 1.45.  
     
     
         30 . An antireflection-treated article obtained by forming the antireflection film of any of  claims 20  to  29  on a substrate.  
     
     
         31 . The antireflection-treated article of  claim 30 , wherein a material of the substrate is at least one selected from the group consisting of an acrylic resin, polycarbonate, polyethylene terephthalate, polyolefin and triacetyl cellulose.  
     
     
         32 . A fluorine-containing unsaturated compound represented by the formula (4-1):  
       CX 1 X 2 ═CX 3 —(CX 4 X 5 ) a —(O) c —Rf′  (4-1)  
       wherein X 1  and X 2  are the same or different and each is H or F; X 3  is H, F, CH 3  or CF 3 ; X 4  and X 5  are the same or different and each is H, F or CF 3 ; Rf′ is an organic group in which 1 to 3 of Y 3  (Y 3  is a monovalent organic group having 2 to 10 carbon atoms and an ethylenic carbon-carbon double bond at its end) are bonded to a fluorine-containing alkyl group having 1 to 40 carbon atoms or a fluorine-containing alkyl group having 2 to 100 carbon atoms and ether bond; a is 0 or an integer of from 1 to 3; c is 0 or 1,  
       said Y 3  is an organic group represented by the formula:  
       —(O) d —(C═O)—Y 4    
       wherein Y 4  is an alkenyl group or fluorine-containing alkenyl group having 2 to 5 carbon atoms and an ethylenic carbon-carbon double bond at its end, d is 0 or 1.  
     
     
         33 . The fluorine-containing unsaturated compound of  claim 32  which is represented by the formula (4-3):  
       CH 2 ═CF—CF 2 —O—Rf′  (4-3)  
       wherein Rf′ is as defined in the formula (4-1).  
     
     
         34 . The fluorine-containing unsaturated compound of  claim 32  or  33 , wherein Y 4  is represented by the formula:  
       —O(C═O)CX 6 ═CX 7 X 8    
       wherein X 6  is H, F, CH 3  or CF 3 ; X 7  and X 8  are the same or different and each is H or F.