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; wherein the 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 different from the group G1; 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. If the weight percentage of compounds B>24 wt %, then the weight percentage of compounds C>1 wt %; and wherein all weight percentages of A, B and C are based upon the 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. The polymerizable compound A has a copolymerization ratio of 0.002< r 2/ r 1<0.200 with r1 and r2 representing the copolymerization parameters of methyl-G1 respectively methyl-G2 determined according to the method of Kelen-Tudos.
1. 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 polymeric initiators and polymerizable initiators;
a polymerizable composition consisting essentially 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;
one or more polymerizable compounds B selected from the group consisting of monofunctional acrylates and difunctional acrylates in an amount up to 55 wt %; 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< r 2 / r 1 <0.200
with r 1 and r 2 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
r 1
r 2
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.
2. The free radical curable liquid 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 liquid according to claim 2 , wherein the integers n and m both have a value equal to 0.
4. The free radical curable liquid according to claim 1 , wherein a molecular weight of compound A is smaller than 800 Dalton.
5. The free radical curable liquid according to claim 1 , wherein the ethylenically unsaturated polymerizable functional group G2 is a vinyl ether group.
6. The free radical curable liquid 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 liquid according to claim 1 , wherein the liquid includes a polymerizable photoinitiator.
8. The free radical curable liquid according to claim 1 , wherein the liquid includes a polymerizable co-initiator and/or a polymerizable inhibitor.
9. 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 polymeric initiators and polymerizable initiators;
a polymerizable composition consisting essentially 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< r 2 / r 1 <0.200
with r 1 and r 2 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
r 1
r 2
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
wherein the liquid includes a polymerizable co-initiator and/or a polymerizable inhibitor; and
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 NR 1;
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
R 1 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.
10. A free radical curable printing ink comprising:
a colorant; and
the free radical curable liquid according to claim 1 .
11. The free radical curable printing ink according to claim 10 , wherein the colorant includes a pigment.
12. A packaging material for packaging food comprising:
a cured layer of the free radical curable printing ink according to claim 10 .
13. A printing method comprising:
providing the free radical curable liquid as defined by claim 1 ; and
applying a layer of the free radical curable liquid on a substrate.
14. The printing method according to claim 13 , wherein the layer includes a pigment.
15. The printing method according to claim 13 , wherein the layer is a white layer including a titanium dioxide pigment.
16. The printing method according to claim 13 , 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.
17. The printing method according to claim 13 , further comprising the step of curing the layer with electron beams.