Preparation of a stable composition of radically copolymerisable monomers which contains at least one monomer having urea function(s)

• Main Authors: Bear, Marie-Maud, Lafosse, Xavier
• Format: Patent
• Language: English
• Published: 04.03.2003

The present invention relates to the preparation of a stable composition of radically polymerisable monomers, containing at least one monomer having urea function(s). Said composition is stable despite the joint presence within it of said monomer(s) having urea function(s) and at least one monomer of another type which is radically copolymerisable. Disclosed is a method of preparing a stable composition of radically copolymerizable monomers, said composition containing firstly at least one monomer which has at least one urea function in its formula and secondly at least one monomer which does not have an isocyanate function in its formula, said method comprising preparing said monomer(s) having urea function(s) by reaction of two types of reagent: at least one radically copolymerizable monomer which has at least one isocyanate function in its formula with at least one amine selected from primary and secondary amines, and incorporating said monomer(s) which does(do) not have an isocyanate function in its(their) formula, prior to said reaction, together with one of said reagents, before adding the other of said reagents, and/or during the addition of said reagents, and/or after said reaction. Characteristically, within the context of said method, said reaction for preparing said monomer(s) having urea function(s) is carried out in the absence of non-radically polymerizable solvent, with said reagents, monomer(s) having isocyanate function(s) and amine(s), being incorporated in relative proportions such that the isocyanate equivalent/amine equivalent ratio be between 0.98 and 1.02, and advantageously equal to 1, and said monomer(s) having urea function(s) obtained at the end of said reaction is(are) maintained diluted in the solvent which is constituted of said monomer(s) which does(do) not have an isocyanate function in its(their) formula, in the presence of dissolved oxygen.