Room temperature curable organopolysiloxane compositions

Abstract

A room temperature curable organopolysiloxane composition comprising (A) an organopolysiloxane of HO(SiR 1 2 O) n H and/or (R 2 O) 3−m R 1 m SiO(SiOR 1 2 O) n SiR 1 m (OR 2 ) 3−m wherein R 1 is a monovalent C1-10 hydrocarbon radical, R 2 is a monovalent C1-6 hydrocarbon radical, n is an integer of at least 10, and m is 0 or 1, (B) a silane compound having at least two hydrolyzable radicals, the remaining radicals being methyl, ethyl, propyl, vinyl or phenyl, and/or a partial hydrolyzate thereof, and (C) an organosilicon compound of (RO) p R 1 3−p SiR 3 —NH—R 4 —NH 2 wherein R 1 and R 2 are as defined above, R 3 is a divalent C1-10 hydrocarbon radical, R 4 is a divalent aromatic ring-bearing C7-10 hydrocarbon radical, and p is 1, 2 or 3, at least one of the NH and NH 2 radicals being not directly attached to the aromatic ring in R 4 , cures into silicone rubber which has improved adherence even upon exposure to hot steam.

1 . A room temperature curable organopolysiloxane composition comprising 
 (A) 100 parts by weight of an organopolysiloxane of the following general formula (1):   HO(SiR 1   2 O) n H  (1)   wherein R 1  is a substituted or unsubstituted monovalent hydrocarbon radical of 1 to 10 carbon atoms, and n is an integer of at least 10, or an organopolysiloxane of the following general formula (2):                          wherein R 1  and n are as defined above, R 2  is a substituted or unsubstituted monovalent hydrocarbon radical of 1 to 6 carbon atoms, and m is independently an integer of 0 or 1, or both,    (B) 0.1 to 30 parts by weight of a silane compound having at least two hydrolyzable radicals each attached to a silicon atom in a molecule, the remaining radicals attached to silicon atoms being selected from the group consisting of methyl, ethyl, propyl, vinyl and phenyl, or a partial hydrolyzate thereof or both, and    (C) 0.1 to 10 parts by weight of an organosilicon compound of the following general formula (3):                          wherein R 1  and R 2  are as defined above, R 3  is a divalent hydrocarbon radical of 1 to 10 carbon atoms, R 4  is a divalent aromatic ring-bearing hydrocarbon radical of 7 to 10 carbon atoms, and p is an integer of 1 to 3, at least one of the NH and NH 2  radicals being not directly attached to the aromatic ring in R 4 .    
     
     
         2 . The composition of  claim 1  wherein the hydrolyzable radicals in component (B) are selected from among ketoxime, alkoxy, and isopropenoxy radicals.  
     
     
         3 . The composition of  claim 1  wherein in formula (3), R 2  is methyl or ethyl, and R 3  is methylene, ethylene or propylene.  
     
     
         4 . The composition of  claim 1  wherein in formula (3), R 4  is selected from the following structures:  
       
         
           
                 
                 
                 
               
                     
                     
                 
                     
                     
                 
                     
                   -CH 2 -C 6 H 4 - 
                    (4), 
                 
                     
                   -CH 2 -C 6 H 4 -CH 2 - 
                    (5), 
                 
                     
                   -CH 2 -C 6 H 4 -CH 2 -CH 2 - 
                    (6), 
                 
                     
                   -CH 2 -C 6 H 4 -CH 2 -CH 2 -CH 2 - 
                    (7), 
                 
                     
                   -CH 2 -CH 2 -C 6 H 4 - 
                    (8), 
                 
                     
                   -CH 2 -CH 2 -C 6 H 4 -CH 2 - 
                    (9), 
                 
                     
                   -CH 2 -CH 2 -C 6 H 4 -CH 2 -CH 2 - 
                   (10), 
                 
                     
                   -CH 2 -CH 2 -CH 2 -C 6 H 4 - 
                   (11) and 
                 
                     
                   -CH 2 -CH 2 -CH 2 -C 6 H 4 -CH 2 - 
                   (12). 
                 
                     
                     
                 
                     
                     
                 
             
                
                
               
               
                
                
                
                
                
                
                
                
                
                
                
               
            
           
         
       
     
     
         5 . The composition of  claim 1  which further comprises a filler.  
     
     
         6 . The composition of  claim 5  wherein the filler is silica and/or carbon black.  
     
     
         7 . The composition of  claim 1  which further comprises a condensation reaction catalyst.