Multifunctional acrylic ether-ester products modified with carboxylic anhydride or its polyacid form, process for preparing same and associated crosslinkable compositions

Abstract

The invention relates to a multifunctional acrylic product having a number-average functionality f of acrylate groups greater than 2.1, which is the product of reaction by esterification and by etherification, via Michael addition reaction, between a) a polyol or a mixture of polyols R(OH)having a functionality m of at least 3 for a polyol alone or having an average functionality greater than 2.1 for a mixture of polyols, and b) the acrylic acid (ROH) in the presence of c) at least one cyclic polycarboxylic anhydride or of its polyacid form having a carboxy functionality z of at least 2 and up to 4, the ratio rof number of carboxy groups of said anhydride or polyacid c) with respect to those of the acrylic acid b) r=COHc/COHb being from 0.01 to 0.4 with overall r=COH/OH<1, said acrylic product comprising in its composition both: The invention also relates to a process for preparing said product, to crosslinkable compositions comprising same and to the use thereof in coatings, sealing, moulding or composite compositions, chemical sealing compositions, 3D printing compositions or compositions for 3D objects produced layer-by-layer. One particular advantage of these compositions is their low shrinkage despite their high functionality.