1  US 6,946,538 B2  2  CATALYST FOR ISOCYANATE  CONDENSATION, COMPOSITION  CONTAINING SAME, METHOD FOR USE,  AND RESULTING COMPOSITIONS  According to one embodiment of the invention, it is  possible, but without this exhibiting a specific advantage, for  the anionic compound of formula 1 to exhibit more than one  Thus, according to the invention, saline compounds are  used as catalysts for the ( cyclo )condensation of an isocyan- ate functional group, advantageously an aliphatic, including  cycloaliphatic, functional group, in which ( cyclo) 65  condensation said saline compound is selected from those  which correspond to the formula:  in which:  Advantageously, Y represents a radical of formula (II):  (II)  This is because the anionic compounds of formula (I) are  capable of forming compounds with the isocyanates, in  particular resulting from the addition to the isocyanate  functional group. The additions of the anion take place on  the carbon of the isocyanate functional group.  In addition, it has been surprisingly discovered that sila- zane salts or silanolates made it possible to catalyze the  polycondensation, in particular the ( cyclo )trimerization, of  isocyanates in which the isocyanate functional group is  hindered and therefore not very accessible, in particular the  isocyanates in which the isocyanate functional group is  carried by a secondary, in particular cycloaliphatic, tertiary  or neopentyl carbon atom. What is more, the associated  cations can be varied in order to balance, in an unusual way,  the various oligocondensate entities resulting from the  ( cyclo )condensation.  Surprisingly, the kinetics of the trimerization reaction and  the reactivity of the isocyanate monomers are substantially  improved when a silazane salt is used in comparison with the  corresponding protonated silazane derivative.  and from those carrying a trialkylsilyl group and resulting  from the reaction of said compounds of formula  (I)  and of  an isocyanate functional group, advantageously an aliphatic  isocyanate functional group.  The studies of the inventors which have led to the present  invention have made it possible to discover that the  polycondensation, in particular trimerization, reaction of  isocyanate monomers could be carried out with salts with  silazane or silanolate structures (nontoxic compounds)  employed in a low amount at a not very high temperature  with an excellent productive output, this being the case  without resulting in significant coloring of the reaction  medium.  European patent EP 57 653 (Rhone-Poulenc) discloses  hexamethyidisilazane  (HMDZ)  as trimerization catalyst for  aliphatic diisocyanates. However, the amounts of catalyst  used and the reaction temperatures are markedly greater than  those employed for quaternary ammonium carboxylates, for  example of the order of 1.25% by weight of catalyst with  respect to  HDI  and 120°  C.  Generally, quaternary ammonium carboxylates with the  hydroxyalkyl functional group are the catalysts of choice for  aliphatic diisocyanates. They give good results at low tern- perature (70 to 80°  C.) and in low amount ( of the order of  0.07% by weight with respect to the diisocyanate).  where  y- is  selected from:  However, the kinetics of this reaction depend on the  structure of the isocyanate and it may be opportune to  choose the catalyst according to the nature of the isocyanate.  The trimerization, in particular cyclotrimerization, reac- tion of isocyanates is a known reaction generally catalyzed  by:  The invention relates to a novel process for the catalytic  ( cyclo )condensation, in particular ( cyclo )trimerization, of  isocyanates.  where (Mn+)i;n symbolizes the cocation(s) necessary for  the electrical neutrality of said saline compound bal› ancing the anion of formula (I):  basic catalysts: quaternary ammoniums or their hydroxy› alkyl derivatives, alkoxides, phenoxides, Mannich  bases, tertiary amines, imide salts, and the like,  organometallic catalysts: alkyl titanates, lead  carboxylates, and the like.  (I)  a negatively charged oxygen;  and a carbonaceous radical compnsmg a negative  charge carried by an atom from Group  VB  or by an  oxygen, advantageously by a nitrogen, and for which  the bond with the silicon of the above formula (I) is  carried by an atom from Group  VB,  advantageously  by a nitrogen;  where  R$_{1}$ ,  R$_{2 }$ and  R$_{3}$ ,  which are identical or different,  represent a monovalent hydrocarbonaceous group  advantageously having from 1 to 30 carbon atoms  which is optionally substituted by one or more halogen  atoms or CN or ester groups and/or is optionally  interrupted by one or more atoms selected from 0, N  and Si, advantageously of aliphatic nature, including of  saturated or unsaturated cycloaliphatic and of aralkyl  nature, or of aromatic nature, such as of aryl or alky› lary 1 nature;  Z represents a semimetal from Group VB;  R$_{10 }$ is selected from radicals comprising from 1 to 30  carbon atoms, including silyl and in particular tri› alkylsilyl; and  R$_{11 }$ is selected from a negative (anionic) charge and a  carbonaceous group (advantageously of at most 30  carbon atoms) attached to Z via a carbon simulta› neously of sp $^{2 }$hybridization and carrying a nitrogen,  the nitrogen of which carries a negative (anionic)  charge. 