Curable perfluoropolyether compositions and rubber or gel articles comprising the same

Abstract

Perfluoropolyether compositions are provided comprising (A) a linear perfluoropolyether compound containing at least two alkenyl groups, having a perfluoropolyether structure comprising recurring units —C a F 2a O— in its backbone, and having a Mw of 10,000-100,000; (B) an organosilicon compound containing at least two silicon atom-bonded hydrogen atoms; (C) a reinforcing filler; (D) a hydrosilylation catalyst; and (E) a polyfluoromonoalkenyl compound containing one alkenyl group and having a perfluoropolyether structure in its backbone. The compositions cure into rubber or gel products having improved acid resistance.

1 . A curable perfluoropolyether composition comprising 
 (A) a linear perfluoropolyether compound containing at least two alkenyl groups per molecule, having a perfluoropolyether structure comprising recurring units —C a F 2a O— wherein a is an integer of 1 to 6 in its backbone, and having a weight average molecular weight of 10,000 to 100,000,    (B) an organosilicon compound containing at least two silicon atom-bonded hydrogen atoms per molecule, selected from (B-1) and (B-2): 
 (B-1) a cyclic organohydrogenpolysiloxane containing at least one perfluoroalkyl group or perfluoropolyether substituent group per molecule, and  
 (B-2) an organosilicon compound containing at least one perfluoroalkyl group or perfluoropolyether substituent group per molecule wherein all silicon atom-bonded hydrogen atoms form H—Si(CH 2 ) g Si— structures wherein g is an integer of 1 to 3,  
   (C) a reinforcing filler, and    (D) a hydrosilylation catalyst,    said composition being cured into a rubber.    
   
   
       2 . The curable perfluoropolyether composition of  claim 1 , wherein in component (A), the perfluoropolyether structure comprising recurring units —C a F 2a O— is represented by (C a F 2a O) q  wherein q is an integer of 50 to 600.  
   
   
       3 . The curable perfluoropolyether composition of  claim 1 , wherein component (A) is a linear perfluoropolyether compound having the general formula (1):  
     
       
         
         
             
             
         
       
     
     wherein X is —CH 2 —, —CH 2 O—, —CH 2 OCH 2 — or —Y—NR 1 —CO— wherein Y is —CH 2 — or a dimethylphenylsilylene group of the structural formula (Z):  
     
       
         
         
             
             
         
       
     
     (inclusive of o-, m- and p-positions), and R 1  is hydrogen, methyl, phenyl or allyl, 
 X′ is —CH 2 —, —OCH 2 —, —CH 2 OCH 2 — or —CO—NR 2 —Y— wherein Y is —CH 2 — or a dimethylphenylsilylene group of the structural formula (Z′):  
                     
 (inclusive of o-, m- and p-positions), and R 2  is hydrogen, methyl, phenyl or allyl,  
 p is independently 0 or 1, r is an integer of 2 to 6, m and n each are an integer of 0 to 600, the sum of m+n is 50 to 600.  
 
   
   
       4 . The curable perfluoropolyether composition of  claim 1 , wherein component (C) is fumed silica which has been treated with a silane surface treating agent.  
   
   
       5 . The perfluoropolyether composition of  claim 1 , further comprising (F) at least one linear polyfluoro compound selected from the class consisting of compounds having the general formula (3):  
       A-O—(CF 2 CF 2 CF 2 O) d -A   (3)  
     wherein A is a group of C e F 2e+1 —wherein e is an integer of 1 to 3, and d is an integer of 1 to 500, and compounds having the general formula (4):  
       A-O—(CF 2 O) f (CF 2 CF 2 O) h -A   (4)  
     wherein A is as defined above, and f and h each are an integer of 1 to 300.  
   
   
       6 . The perfluoropolyether composition of  claim 1 , having a fluorine content of at least 60%.  
   
   
       7 . The perfluoropolyether composition of  claim 1 , wherein component (B-1) is a cyclic organohydrogenpolysiloxane having the general formula (5):  
     
       
         
         
             
             
         
       
     
     wherein Rf 3  is monovalent perfluoroalkyl or perfluoropolyether group, R 3  is a monovalent hydrocarbon group of 1 to 20 carbon atoms, R 4  is a divalent hydrocarbon group of 2 to 20 carbon atoms which may contain an ether bond, k is an integer of at least 2, and 1 is an integer of 1 to 6.  
   
   
       8 . The perfluoropolyether composition of  claim 1 , wherein the organosilicon compound wherein all silicon atom-bonded hydrogen atoms form H—Si(CH 2 ) g Si— structures (B-2) has the general formula (6):  
     
       
         
         
             
             
         
       
     
     wherein i and j are 0 or 1, excluding the case where both i and j are 0, 
 in the case where either one of i and j is 0 and the other is 1, Z is hydrogen, -Q-M or -Q-Rf 3 , Q is a divalent hydrocarbon group of 1 to 15 carbon atoms which may contain an ether bond, Rf 3  is a monovalent perfluoroalkyl or perfluorooxyalkyl group, M is a group of formula (i):  
                     
 R 6  is a monovalent hydrocarbon group of 1 to 20 carbon atoms, and g is an integer of 1 to 3,  
 in the case where both i and j are 1, Z is -Q-, -Rf′- or -Q-Rf′-Q-, Q is as defined above, Rf′ is a divalent perfluoroalkylene or perfluorooxyalkylene group, M is a group of the formula (ii) and/or a group of the formula (iii):  
                     
 wherein Rf 4  is monovalent perfluoroalkyl or perfluoropolyether group and Q and g are as defined above, with the proviso that there are present at least two groups of formula (ii) per molecule,  
 R 5  is a monovalent hydrocarbon group of 1 to 20 carbon atoms,  
 t is 1, 2 or 3, and u is 0, 1, 2 or 3.  
 
   
   
       9 . The perfluoropolyether composition of  claim 1 , which cures into a product having a weight gain of up to 6% when saturated in gasoline at 23° C.  
   
   
       10 . The perfluoropolyether composition of  claim 1 , which cures into a product having a weight gain of up to 8% when immersed in conc. sulfuric acid (98%) at 23° C.  
   
   
       11 . A rubber article comprising the curable perfluoropolyether composition of  claim 1  in the cured state.  
   
   
       12 . A rubber article comprising the curable perfluoropolyether composition of  claim 1  in the cured state, for use in automobiles, chemical plants, ink jet printers, semiconductor manufacturing lines, analytical or scientific instruments, medical equipment, aircraft or fuel cells.  
   
   
       13 . A curable perfluoropolyether composition comprising 
 (A) a linear perfluoropolyether compound containing at least two alkenyl groups per molecule, having a perfluoropolyether structure comprising recurring units —C a F 2a O— wherein a is an integer of 1 to 6 in its backbone, and having a weight average molecular weight of 10,000 to 100,000,    (B) an organosilicon compound containing at least two silicon atom-bonded hydrogen atoms per molecule, selected from (B-1) and (B-2): 
 (B-1) a cyclic organohydrogenpolysiloxane containing at least one perfluoroalkyl group or perfluoropolyether substituent group per molecule, and  
 (B-2) an organosilicon compound containing at least one perfluoroalkyl group or perfluoropolyether substituent group per molecule wherein all silicon atom-bonded hydrogen atoms form H—Si(CH 2 ) g Si— structures wherein g is an integer of 1 to 3,  
   (D) a hydrosilylation catalyst, and    (E) a polyfluoromonoalkenyl compound containing one alkenyl group per molecule and having a perfluoropolyether structure in its backbone,    said composition being cured into a gel.    
   
   
       14 . The curable perfluoropolyether composition of  claim 13 , wherein in component (A), the perfluoropolyether structure comprising recurring units —C a F 2a O— is represented by (C a F 2a O) q  wherein q is an integer of 50 to 600.  
   
   
       15 . The curable perfluoropolyether composition of  claim 13 , wherein component (A) is a linear perfluoropolyether compound having the general formula (1):  
     
       
         
         
             
             
         
       
     
     wherein X is —CH 2 —, —CH 2 O—, —CH 2 OCH 2 — or —Y—NR 1 —CO— wherein Y is —CH 2 — or a dimethylphenylsilylene group of the structural formula (Z):  
     
       
         
         
             
             
         
       
     
     (inclusive of o-, m- and p-positions), and R 1  is hydrogen, methyl, phenyl or allyl, 
 X′ is —CH 2 —, —OCH 2 —, —CH 2 OCH 2 — or —CO—NR 2 —Y— wherein Y is —CH 2 — or a dimethylphenylsilylene group of the structural formula (Z′):  
                     
 (inclusive of o-, m- and p-positions), and R 2  is hydrogen, methyl, phenyl or allyl,  
 p is independently 0 or 1, r is an integer of 2 to 6, m and n each are an integer of 0 to 600, the sum of m+n is 50 to 600.  
 
   
   
       16 . The perfluoropolyether composition of  claim 13 , wherein component (E) is a polyfluoromonoalkenyl compound having the general formula (2):  
       Rf 2 -(X′) p —CH═CH 2    (2)  
     wherein X′ and p are as defined above, Rf 2  is a group of the general formula:  
       F—[CF(CF 3 )CF 2 O] w —CF(CF 3 )— 
     wherein w is an integer of 1 to 500.  
   
   
       17 . The perfluoropolyether composition of  claim 13 , further comprising (F) at least one linear polyfluoro compound selected from the class consisting of compounds having the general formula (3):  
       A-O—(CF 2 CF 2 CF 2 O) d -A   (3)  
     wherein A is a group of C e F 2e+1 —wherein e is an integer of 1 to 3, and d is an integer of 1 to 500, and compounds having the general formula (4):  
       A-O—(CF 2 O) f (CF 2 CF 2 O) h -A   (4)  
     wherein A is as defined above, and f and h each are an integer of 1 to 300.  
   
   
       18 . The perfluoropolyether composition of  claim 13 , having a fluorine content of at least 60%.  
   
   
       19 . The perfluoropolyether composition of  claim 13 , wherein component (B-1) is a cyclic organohydrogenpolysiloxane having the general formula (5):  
     
       
         
         
             
             
         
       
     
     wherein Rf 3  is monovalent perfluoroalkyl or perfluoropolyether group, R 3  is a monovalent hydrocarbon group of 1 to 20 carbon atoms, R 4  is a divalent hydrocarbon group of 2 to 20 carbon atoms which may contain an ether bond, k is an integer of at least 2, and 1 is an integer of 1 to 6.  
   
   
       20 . The perfluoropolyether composition of  claim 13 , wherein the organosilicon compound wherein all silicon atom-bonded hydrogen atoms form H—Si(CH 2 ) g Si— structures (B-2) has the general formula (6):  
     
       
         
         
             
             
         
       
     
     wherein i and j are 0 or 1, excluding the case where both i and j are 0, 
 in the case where either one of i and j is 0 and the other is 1, Z is hydrogen, -Q-M or -Q-Rf 3 , Q is a divalent hydrocarbon group OF 1 to 15 carbon atoms which may contain an ether bond, Rf 3  is a monovalent perfluoroalkyl or perfluorooxyalkyl group, M is a group of formula (i):  
                     
 R 6  is a monovalent hydrocarbon group of 1 to 20 carbon atoms, and g is an integer of 1 to 3,  
 in the case where both i and j are 1, Z is -Q-, -Rf′- or -Q-Rf′-Q-, Q is as defined above, Rf′ is a divalent perfluoroalkylene or perfluorooxyalkylene group, M is a group of the formula (ii) and/or a group of the formula (iii):  
                     
 wherein Rf 4  is monovalent perfluoroalkyl or perfluoropolyether group and Q and g are as defined above, with the proviso that there are present at least two groups of formula (ii) per molecule,  
 R 5  is a monovalent hydrocarbon group of 1 to 20 carbon atoms,  
 t is 1, 2 or 3, and u is 0, 1, 2 or 3.  
 
   
   
       21 . The perfluoropolyether composition of  claim 13 , which cures into a product having a weight gain of up to 6% when saturated in gasoline at 23° C.  
   
   
       22 . The perfluoropolyether composition of  claim 13 , which cures into a product having a weight gain of up to 8% when immersed in conc. sulfuric acid (98%) at 23° C.  
   
   
       23 . A gel article comprising the curable perfluoropolyether composition of  claim 13  in the cured state.  
   
   
       24 . A gel article comprising the curable 1o perfluoropolyether composition of  claim 13  in the cured state, for use in automobiles, chemical plants, ink jet printers, semiconductor manufacturing lines, analytical or scientific instruments, medical equipment, aircraft or fuel cells.