PROCESS FOR THE PREPARATION OF RADIATION CURABLE COMPOSITIONS
The present invention relates to a process for the preparation of radiation curable compositions comprising at least one radiation curable (meth)acrylic copolymer A and at least one (meth)acrylated epoxy compound B, said process comprising:—the preparation of a copolymer P by copolymerization of monomers comprising: (i) from 0.1 to 50 mole % of at least one epoxy (meth)acrylate (a1), and (ii) from 50 to 99.9 mole % of at least one other copolymerizable monomer (m) different from (a1) in the presence of at least one non-copolymerizable epoxy compound (b1) and—further reacting copolymer P thereby obtained and the non-copolymerizable epoxy compound (b1) with at least one carboxylic (meth)acrylate (a3).
1 . Process for the preparation of a radiation curable composition comprising at least one radiation curable (meth)acrylic copolymer A and at least one (meth)acrylated epoxy compound B, said process comprising:
the preparation of a copolymer P by copolymerization of monomers comprising:
(i) from 0.1 to 50 mole % of at least one epoxy (meth)acrylate (a1), and
(ii) from 50 to 99.9 mole % of at least one other copolymerizable monomer (m) different from epoxy (meth)acrylate (a1)
in the presence of at least one non-copolymerizable epoxy compound (b1) and
further reacting copolymer P thereby obtained and the non-copolymerizable epoxy compound (b1) with at least one carboxylic (meth)acrylate (a3).
2 . Process according to claim 1 wherein the epoxy (meth)acrylate (a1) is glycidyl(meth)acrylate.
3 . Process according to claim 1 wherein the carboxylic (meth)acrylate (a3) is (meth)acrylic acid.
4 . Process according to claim 1 wherein the other copolymerizable monomer (m) is selected from (meth)acrylates (m1), vinylic compounds (m2) and mixtures thereof.
5 . Process according to claim 4 wherein the (meth)acrylate (m1) is selected from alkyl(meth)acrylates wherein the alkyl group comprises from 1 to 24 carbon atoms.
6 . Process according to claim 4 wherein the vinylic compound (m2) is styrene.
7 . Process according to claim 1 wherein the non-copolymerizable epoxy compound (b1) is selected from epoxidized olefins, epoxidized phenol-formaldehyde copolymers, epoxidized natural oils, mono- and polyglycidyl esters, mono- and polyglycidyl ethers and mixtures thereof.
8 . Process according to claim 7 wherein the non-copolymerizable epoxy compound (b1) is selected from the monoglycidyl esters of long chain alkyl carboxylic acids wherein the alkyl chain comprises from 6 to 24 carbon atoms.
9 . Process according to claim 1 wherein:
(i) from 5 to 60% by weight of non-copolymerizable epoxy compound (b1), and
(ii) from 40 to 95% by weight of monomers comprising the epoxy (meth)acrylate (a1) and other copolymerizable monomer (m)
based on the total weight of non-copolymerizable epoxy compound (b1) and monomers comprising at least one epoxy (meth)acrylate (a1) and at least one other copolymerizable monomer (m) are used.
10 . Process according to claim 1 wherein the equivalent ratio of carboxylic (meth)acrylate (a3) to the total amount of epoxy groups provided by copolymer P and the non-copolymerizable epoxy compound (b1) is from 0.5 to 1.0.
11 . Process according to claim 1 comprising a step wherein at least one radiation curable compound C is added before and/or after the esterification step, partially or completely.
12 . A radiation curable composition obtained by the process of claim 1 comprising:
(i) from 60 to 98% by weight of (meth)acrylic copolymer A, and
(ii) from 2 to 40% by weight of (meth)acrylated epoxy compound B
based on the total weight of (meth)acrylic copolymer A and of (meth)acrylated epoxy compound B.
13 . A radiation curable composition according to claim 12 comprising less than 1% by weight of solvent based on the total weight of (meth)acrylic copolymer A and of (meth)acrylated epoxy compound B.
14 . A radiation curable composition according to claim 12 comprising:
(i) from 15 to 95% by weight of (meth)acrylic copolymer A, and
(ii) from 2 to 40% by weight of (meth)acrylated epoxy compound B, and
(iii) from 2 to 40% by weight of at least one radiation curable compound different from (meth)acrylic copolymer A and (meth)acrylated epoxy compound B
based on the total weight of the composition.
15 . Process for the manufacturing of inks, varnishes, adhesives and coatings wherein a composition according to claim 12 is used.
16 . Inks, varnishes, adhesives or coatings comprising a radiation curable composition according to claim 12 .