Curable liquids and inks for toys and food packaging applications
View Patent ↗A free radical curable liquid for inkjet printing of food packaging materials includes no initiator or otherwise one or more initiators selected from the group consisting of non-polymeric di- or multifunctional initiators, oligomeric initiators, polymeric initiators, and polymerizable initiators; and a polymerizable composition of the liquid consists essentially of: a) 25-100 wt % of one or more polymerizable compounds A having at least one acrylate group G1 and at least one second ethylenically unsaturated polymerizable functional group G2 selected from the group consisting of a vinlyether group, an allylether group, and a allylester group; b) 0-55 wt % of one or more polymerizable compounds B selected from the group consisting of monofunctional acrylates and difunctional acrylates; and c) 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.
1. A free radical curable ink for printing comprising:
a colorant;
no initiator;
a polymerizable composition consisting essentially of:
25-100 wt % of one or more polymerizable compounds A having at least one acrylate group G1 and at least one ethylenically unsaturated polymerizable functional group G2 selected from the group consisting of a vinylether group, an allylether group, and an allylester group;
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 %; and
a polymerizable inhibitor; wherein
all weight percentages of A, B, and C are based upon a total weight of the polymerizable composition; and
at least one polymerizable compound B or C is present.
2. The free radical curable ink according to claim 1 , wherein the compound A is represented by the Formula (I):
wherein
GX and GY are independently selected from the group consisting of G1 and G2;
n and m are independently selected integers having a value of 0 or 1; and
L represents a (n+m+2)-valent linking group including at least one carbon atom.
3. The free radical curable ink according to claim 2 , wherein the integers n and m both have a value equal to 0.
4. The free radical curable ink according to claim 1 , wherein a molecular weight of compound A is smaller than 800 Dalton.
5. The free radical curable ink according to claim 1 , wherein the ethylenically unsaturated polymerizable functional group G2 is a vinylether group.
6. The free radical curable ink according to claim 1 , wherein the polymerizable composition includes 60 wt % to 90 wt % of one or more polymerizable compounds A and 10 wt % to 40 wt % of one or more polymerizable compounds C.
7. The free radical curable ink according to claim 1 , wherein 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.
8. The free radical curable ink according to claim 1 , wherein the colorant is a pigment.
9. The free radical curable ink according to claim 1 , wherein the free radical curable ink is an inkjet ink.
10. A packaging material for packaging food comprising:
a cured layer of the free radical curable ink according to claim 1 .
11. A printing method comprising:
providing the free radical curable ink as defined by claim 1 ; and
applying a layer of the free radical curable ink on a substrate.
12. The printing method according to claim 11 , wherein the layer includes a pigment.
13. The printing method according to claim 11 , wherein the layer is a white layer including a titanium dioxide pigment.
14. The printing method according to claim 11 , wherein the layer is applied by:
a printing technique selected from the group consisting of inkjet printing, flexographic printing, offset printing, and screen printing; or
a coating technique selected from the group consisting of dip coating, knife coating, extrusion coating, spin coating, slide hopper coating, and curtain coating.
15. The printing method according to claim 11 , further comprising the step of curing the layer with electron beams.