Silicone composition that can be cross-linked by means of dehydrogenative condensation in the presence of a carbene-type catalyst

Abstract

The invention relates to a silicone composition comprising components bearing ═SiH/═SiOH groups, which can be polymerised/cross-linked by means of a dehydrogenative condensation reaction in the presence of a carbene-type catalyst in solution.

1 . A catalytic composition Y′ comprising:
 a) a catalytically effective amount of at least one polycondensation catalyst A which is a carbene of formula (I) below: 
 
       
         
           
           
               
               
           
         
         with:
 the symbol X being chosen from the group consisting of the following atoms or groups: —O—, —S—, —N(R)— and —P(R)— with R being a C 1 -C 30  group, 
 R 1 , R 2  and R 3  being identical or different, optionally substituted, C 1 -C 30  groups optionally comprising at least one atoms selected from the group consisting of: S, P, Si, N and O, and 
 the symbols X, R 1 , R 2  and R 3  taken in pairs can form a 5-, 6- or 7-membered ring, and 
 
         b) at least one solvent comprising at least one alcohol G;
 optionally at least one polyorganosiloxane resin D; and 
 optionally at least one filler E. 
 
       
     
     
         2 . The composition as claimed in  claim 1 , comprising said at least one polyorganosiloxane resin D. 
     
     
         3 . The composition as claimed in  claim 1 , comprising said at least one filler E. 
     
     
         4 . The composition as claimed in  claim 1 , wherein the at least one alcohol G is selected from one or more of the group consisting of methanol, ethanol, propanol, and butanol. 
     
     
         5 . The composition as claimed in  claim 6 ,
 wherein the catalyst A is of formula (II) or (II′):   
       
         
           
           
               
               
           
         
         in which:
 the symbols A 1  and A 2  independently represent a carbon or nitrogen atom, it being understood that: 
 
         1) in formula (II), when the symbol A 1  represents a nitrogen atom, then the symbol T 4  is not present, and when the symbol A 2  represents a nitrogen atom, then the symbol T 3  is not present; and 
         2) in formula (II′), when the symbol A 1  represents a nitrogen atom, then the symbol T 4  or T 4′  is not present, and when the symbol A 2  represents a nitrogen atom N, then the symbol T 3  or T 3′  is not present;
 the symbols T 3 , T 3′ , T 4  and T 4′  independently represent a hydrogen atom; or one of the following groups: alkyl, cycloalkyl optionally substituted with an alkyl or alkoxy group, aryl optionally substituted with an alkyl or alkoxy group, alkenyl, alkynyl or arylalkyl in which the aryl part is optionally substituted with an alkyl or alkoxy group; 
 the symbols T 3  and T 4  can form, together and with A 1  and A 2 , when the latter each represent a carbon atom, an aryl, it being understood that, in this case, T 3′  and T 4′  are not present; 
 the symbols T 1 , T 2 , T 3 , T 3′ , T 4  and T 4′  can form, in pairs, when they are located on two adjacent ring members in formulae (II) and (II′), a saturated or unsaturated hydrocarbon-based chain, and 
 the symbols T 1  and T 2  represent, independently of one another: 
 
         1) one of the following groups: alkyl, a cycloalkyl optionally substituted with an alkyl group, alkyl which is perfluorinated or optionally substituted with a perfluoroalkyl group, cycloalkyl optionally substituted with an alkyl or alkoxy group, aryl optionally substituted with an alkyl or alkoxy group, alkenyl, alkynyl or arylalkyl in which the aryl part is optionally substituted with an alkyl or alkoxy group; or 
         2) a monovalent radical of formula (IV) below:
   —V1-V2  (IV)
 
 
         in which:
 V1 is a saturated or unsaturated, divalent hydrocarbon-based group, optionally a linear or branched C 1 -C 10  alkylene, which is optionally substituted, and 
 V2 is a monovalent group selected from the group consisting of the following substituents: 
 alkoxy, —OR a  with the symbol R a  corresponding to a hydrogen atom or an alkyl or aryl group; 
 silyl, —Si(OR b )—(R c ) 3-x  with the symbol R b  corresponding to a hydrogen atom or an alkyl, silyl or siloxanyl group, with the symbol R c  corresponding to an alkyl or aryl group and the symbol x being an integer equal to 0, 1, 2 or 3; and 
 amine, optionally —N(R a ) 2  with the symbol R a  corresponding to a hydrogen atom or to an alkyl or aryl group. 
 
       
     
     
         6 . The composition as claimed in  claim 1 , wherein the alcohol G is present in the catalytic composition Y′ in a proportion of at least 50% by weight relative to the total weight of the catalytic composition Y′. 
     
     
         7 . The composition as claimed in  claim 1 , composed exclusively of one or more alcohols G and one more polycondensation catalyst A.