Photo-curable fluoropolyether-based rubber composition, curing method thereof and cured product obtained by the curing method

Abstract

A photo-curable composition having superior curability at room temperature and storage stability, and also offer a rubber-like cured product thereof having a good profile of properties including heat resistance, low-temperature performance, chemical resistance, solvent resistance and oil resistance. Specifically, A photo-curable composition which includes (A) 100 parts by mass of a linear polyfluoro compound having at least two alkenyl groups in a molecule and a linear perfluoropolyether structure in a backbone of the molecule, (B) a fluorine-containing organohydrogenpolysiloxane having at least two hydrogens bonded to a silicon atom in a molecule, and (C) 0.1 to 500 ppm of a photoactive hydrosililation catalyst relative to the mass of component (A) in terms of metal atom, wherein an amount of component (B) is 0.5 to 3.0 mol of Si—H groups in component (B) relative to 1.0 mol of alkenyl groups in component (A).

What is claimed is: 
     
         1 . A photo-curable fluoropolyether-based rubber composition comprising:
 (A) 100 parts by mass of a linear polyfluoro compound having:
 at least two alkenyl groups per molecule; and 
 a linear perfluoropolyether structure in a backbone of the molecule, 
   (B) a fluorine-containing organohydrogenpolysiloxane having at least two hydrogens bonded to a silicon atom per molecule, said fluorine-containing organohydrogenpolysiloxane containing 0.5 to 3.0 mol of Si—H groups based on 1.0 mol of alkenyl groups in component (A) and   (C) 0.1 to 500 ppm of a photoactive hydrosililation catalyst based on the mass of component (A) in terms of metal atom.   
     
     
         2 . The photo-curable fluoropolyether-based rubber composition according to  claim 1 , wherein component (A) is a linear polyfluoro compound represented by a formula (1):
   [Chemical Formula 1]     CH 2 ═CH—(X) g —Rf 1 —(X′) g —CH═CH 2   (1)
   
       wherein X represents —CH 2 , —CH 2 O—, —CH 2 OCH 2 —, or —Y—NR 1 —CO—, wherein Y represents —CH 2 —, —Si(CH 3 ) 2 CH 2 CH 2 CH 2 —. —Si(CH 3 )(CH═CH 2 )CH 2 CH 2 CH 2 —, —Si(CH═CH 2 ) 2 CH 2 CH 2 CH 2 —, or an o-, m-, or p-silylphenylene group represented by a structural formula (Z) shown below, 
       
         
           
           
               
               
           
         
       
       wherein each of R 3  and R 4  independently represents —CH 3  or —CH═CH 2 , and R 1  represents a hydrogen atom or a substituted or unsubstituted monovalent hydrocarbon group, X′ represents —CH 2 —, —OCH 2 —, —OH 2 OCH 2 —, or —CO—NR 2 —Y′—, wherein Y′ represents —CH 2 —, —CH 2 CH 2 CH 2 Si(CH 3 ) 2 —, —CH 2 CH 2 CH 2 Si(CH 3 )(CH═CH 2 )—, —CH 2 CH 2 CH 2 Si(CH═CH 2 ) 2 — or an o-, m-, or p-silylphenylene group represented by a structural formula (Z′) shown below 
       
         
           
           
               
               
           
         
       
       wherein each of R 3′  and R 4′  independently represents —CH 3  or —CH═CH 2 , and R 2  represents a hydrogen atom or a substituted or unsubstituted monovalent hydrocarbon group, g independently represents an integer of 0 or 1, and Rf 1  is a linear divalent perfluoropolyether group represented by a formula (i) or formula (ii) shown below, 
       
         
           
           
               
               
           
         
       
       wherein each of p and q representing an integer of 0 to 150, provided that an average of the sum of p and q is from 2 to 200, r representing an integer of 0 to 6, and t representing an integer of 2 or 3, 
       
         
           
           
               
               
           
         
       
       wherein u representing an integer of 1 to 200, v representing an integer of 1 to 50, and t representing an integer of 2 or 3. 
     
     
         3 . The photo-curable fluoropolyether-based rubber composition according to  claim 1 , wherein the fluorine-containing organohydrogenpolysiloxane of component (B) has at least one monovalent perfluoroalkyl group, monovalent perfluorooxyalkyl group, divalent perfluoroalkylene group, or divalent perfluorooxyalkylene group per molecule. 
     
     
         4 . The photo-curable fluoropolyether-based rubber composition according to  claim 1 , wherein the photoactive hydrosililation catalyst of component (C) is (η 5 -cyclopentadienyl)tri(σ-alkyl) platinum (IV) complex compound and/or β-diketonate platinum (II) complex compound. 
     
     
         5 . The photo-curable fluoropolyether-based rubber composition according to  claim 1  further comprising (D) 0.5 to 30 parts by mass of hydrophobic silica powder having BET specific surface area of not less than 50 m 2 /g based on 100 parts by mass of component (A), as a filler. 
     
     
         6 . The photo-curable fluoropolyether-based rubber composition according to  claim 1  further comprising (E) a reaction control agents for hydrosilylation reaction. 
     
     
         7 . A cured product obtained from the photo-curable fluoropolyether-based rubber composition according to  claim 1 . 
     
     
         8 . A curing method of a photo-curable fluoropolyether-based rubber composition comprising:
 irradiating the photo-curable fluoropolyether-based rubber composition according to any one of  claims 1  to  6  with near-ultraviolet radiation whose maximum peak is in the wavelength region from 300 nm to 400 nm.