Catalyst and method for trimerization of isocyanates

A method for preparing polyisocyanurate polyisocyanates by catalytic cyclotrimerization of monomeric isocyanates comprising:

• adding to a reaction medium comprising the monomeric isocyanates a catalyst comprising a hydrogencarbonate of a cation of formula I:
• in which
• Q is selected from the group consisting of a nitrogen, phosphorus and sulphur atom;
• and
• R1, R2, R3 and R4 are identical or different and are selected from the group consisting of unsubstituted or hydroxylated alkyl groups having 1 to 20 carbon atoms, cycloalkyl radicals having 4 to 15 carbon atoms which are unsubstituted or substituted by hydroxyl groups,
• aralkyl radicals having 7 to 15 carbon atoms which are unsubstituted or substituted by hydroxyl groups,
• and aryl radicals having 6 to 15 carbon atoms which are unsubstituted or substituted by hydroxyl groups,
• or, when Q is N, two of the radicals R1, R2, R3 or R4 optionally form together with the nitrogen atom and, optionally, with a heteroatom, selected from oxygen and nitrogen, a heterocyclic ring having 4 to 6 carbon atoms, or, when Q is N, the radicals R1, R2 and R3 are each ethylene radicals which form, in combination with the quaternary nitrogen atom and another tertiary nitrogen atom, a bicyclic triethylenediamine, or one of R1 to R4 is a group
• in which R5, R6 and R7 are identical or different and are selected from the group consisting of hydrogen, an OH group, an alkyl group having 1 to 12 carbon atoms, a cycloalkyl group having 5 to 7 carbon atoms, an alkenyl group having 2 to 15 carbon atoms, an alkynyl group having 3 to 6 carbon atoms, a hydroxyalkyl group having 1 to 9 carbon atoms, an aralkyl group having 7 to 10 carbon atoms, an aryl group having 6 to 10 carbon atoms, and a group of formula R8—O—(CH2)n, in which R8 is selected from the group consisting of hydrogen, an alkyl radical having 1 to 12 carbon atoms, a cycloalkyl radical having 4 to 10 carbon atoms, an aralkyl radical having 7 to 10 carbon atoms and an aryl radical having 6 to 10 carbon atoms, and n is an integer ranging from 1 to 6;
• or R7 is optionally a group of formula OCOR9 in which R9 is a C1-C6 alkyl group;
• allowing the reaction to progress for a period between 1 and 4 hours at a temperature between room temperature and 120° C.;
• and
• isolating the product obtained thereby.

A method of preparing (poly)isocyanurate polyisocyanates by catalytic cyclotrimerization of isocyanates comprising:

• adding to a reaction medium comprising said isocyanates a catalytic system which comprises a cyclotrimerization catalyst based on a quaternary ammonium salt as catalyst and imidazole or one of its derivatives as cocatalyst,
• allowing the reaction to progress for a period between 1 and 4 hours at a temperature between room temperature and 120° C.;
• and
• isolating the product obtained thereby.