Curable liquids and inks for toys and food packaging applications

A free radical curable liquid for use in printing, the free radical curable liquid comprising:

• no initiator or one or more initiators selected from the group consisting of non-polymeric di- or multifunctional initiators, oligomeric initiators, polymeric initiators, and polymerizable initiators;
• a polymerizable composition consisting of:
• 25-100 wt % of one or more polymerizable compounds A including at least one acrylate group G1 and at least one ethylenically unsaturated polymerizable functional group G2 different from the group G1;
• 0-55 wt % of one or more polymerizable compounds B selected from the group consisting of monofunctional acrylates and difunctional acrylates;
• and
• 0-55 wt % of one or more polymerizable compounds C selected from the group consisting of trifunctional acrylates, tetrafunctional acrylates, pentafunctional acrylates, and hexafunctional acrylates, wherein if the weight percentage of compounds B>24 wt %, then the weight percentage of compounds C>1 wt %;
• wherein
• all weight percentages of A, B, and C are based upon a total weight of the polymerizable composition;
• at least one polymerizable compound B or C is present in the polymerizable composition if the free radical curable liquid contains no initiator;
• and
• the polymerizable compound A has a copolymerization ratio of
• 0.002<r2/r1<0.200
• with r1 and r2 representing copolymerization parameters of methyl-G1 and methyl-G2, respectively, determined according to a method of Kelen-Tudos if the combination of G1 and G2 is not listed in the following Table:
• TABLE
• G1-group
• G2-group
• r1
• r2
• acrylate
• allylether
• 11.0
• 0.04
• acrylate
• allylester
• 11.0
• 0.04
• acrylate
• allylcarbonate
• 10.2
• 0.04
• acrylate
• vinylether
• 3.6
• 0.02
• acrylate
• vinylester
• 3.5
• 0.02
• acrylate
• vinylcarbonate
• 3.5
• 0.02
• acrylate
• fumarate
• 1.9
• 0.09
• acrylate
• maleate
• 1.9
• 0.09
• the liquid includes a polymerizable co-initiator and/or a polymerizable inhibitor;
• the polymerizable inhibitor is a polymerizable phenolic polymerization inhibitor according to formula (II):
• wherein
• R represents a hydrogen or a methyl group;
• X represents O or NR1;
• m represents 0 or 1;
• n represents an integer from 1 to 5;
• o represents an integer from 1 to 6;
• A represents a substituted or unsubstituted phenolic moiety;
• L represents a (n+o)-valent linking group including a maximum of 20 carbon atoms;
• and
• R1 represents a group selected from the group consisting of hydrogen, a substituted or unsubstituted alkyl group, a substituted or unsubstituted alkenyl group, a substituted or unsubstituted alkynyl group, a substituted or unsubstituted aralkyl group, a substituted or unsubstituted alkaryl group, a substituted or unsubstituted aryl group, and a substituted or unsubstituted heteroaryl group.