Curable liquids and inks for toys and food packaging applications
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 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.
1. A free radical curable liquid for use in printing, the free radical curable liquid comprising:
one or more initiators selected from the group consisting of polymeric initiators and polymerizable initiators;
a polymerizable co-initiator and/or a polymerizable inhibitor; and
a polymerizable composition consisting essentially of:
25-98 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 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
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; 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
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.
2. The free radical curable liquid according to claim 1 , wherein an amount of polymerizable compounds in the polymerizable composition different from the polymerizable compounds A, B, and C is smaller than 5 wt % based upon the total weight of the polymerizable composition.
3. The free radical curable liquid according to claim 2 , 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.
4. The free radical curable liquid according to claim 3 , wherein the integers n and m both have a value equal to 0.
5. The free radical curable liquid according to claim 4 , wherein a molecular weight of compound A is smaller than 800 Dalton.
6. The free radical curable liquid according to claim 5 , wherein the polymerizable functional group G2 is a vinyl ether group.
7. A free radical curable ink for inkjet printing, the free radical curable ink comprising:
a colorant; and
the free radical curable liquid according to claim 6 .
8. A free radical curable ink for inkjet printing, the free radical curable ink comprising:
a colorant; and
the free radical curable liquid according to claim 1 .
9. A UV-curable pigment inkjet ink set including a free radical curable ink for inkjet printing according to claim 7 .
10. An inkjet printing system comprising:
the free radical curable ink according to claim 7 in a piezoelectric print head.
11. A packaging material for packaging food comprising:
a cured layer of the free radical curable ink according to claim 7 .
12. A free radical curable liquid for use in printing, the free radical curable liquid comprising:
one or more initiators selected from the group consisting of polymeric initiators and polymerizable initiators;
a polymerizable composition consisting essentially of:
25-98 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 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
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; and
the polymerizable compound A includes 2-(vinyloxyethoxy)ethyl acrylate or an allyl ester acrylate according to Formula PC-1:
13. The free radical curable liquid according to claim 12 , wherein an amount of polymerizable compounds in the polymerizable composition different from the polymerizable compounds A, B, and C is smaller than 5 wt % based upon the total weight of the polymerizable composition.
14. The free radical curable liquid according to claim 12 , comprising a compound B selected from the group consisting of alkoxylated cyclohexanone dimethanol diacrylate, alkoxylated hexanediol diacrylate, dioxane glycol diacrylate, dioxane glycol diacrylate, cyclohexanone dimethanol diacrylate, diethylene glycol diacrylate, neopentyl glycol diacrylate, triethylene glycol diacrylate, tetraethylene glycol diacrylate, polyethylene glycol diacrylate, dipropylene glycol diacrylate, tripropylene glycol diacrylate, polypropylene glycol diacrylate, 1,4-butanediol diacrylate, 1,6-hexanediol diacrylate, 1,9-nonanediol diacrylate, neopentyl glycol diacrylate, dimethylol-tricyclodecane diacrylate, bisphenol A EO (ethylene oxide) adduct diacrylate, bisphenol A PO (propylene oxide) adduct diacrylate, hydroxypivalate neopentyl glycol diacrylate, propoxylated neopentyl glycol diacrylate, alkoxylated dimethyloltricyclodecane diacrylate, and polytetramethylene glycol diacrylate.
15. The free radical curable liquid according to claim 13 , comprising a compound B selected from the group consisting of alkoxylated cyclohexanone dimethanol diacrylate, alkoxylated hexanediol diacrylate, dioxane glycol diacrylate, dioxane glycol diacrylate, cyclohexanone dimethanol diacrylate, diethylene glycol diacrylate, neopentyl glycol diacrylate, triethylene glycol diacrylate, tetraethylene glycol diacrylate, polyethylene glycol diacrylate, dipropylene glycol diacrylate, tripropylene glycol diacrylate, polypropylene glycol diacrylate, 1,4-butanediol diacrylate, 1,6-hexanediol diacrylate, 1,9-nonanediol diacrylate, neopentyl glycol diacrylate, dimethylol-tricyclodecane diacrylate, bisphenol A EO (ethylene oxide) adduct diacrylate, bisphenol A PO (propylene oxide) adduct diacrylate, hydroxypivalate neopentyl glycol diacrylate, propoxylated neopentyl glycol diacrylate, alkoxylated dimethyloltricyclodecane diacrylate and polytetramethylene glycol diacrylate.
16. The free radical curable liquid according to claim 14 , further comprising a polymerizable co-initiator and/or a polymerizable inhibitor.
17. A free radical curable ink for inkjet printing, the free radical curable ink comprising:
a colorant; and
the free radical curable liquid according to claim 14 .
18. A free radical curable ink for inkjet printing, the free radical curable ink comprising:
a colorant; and
the free radical curable liquid according to claim 15 .
19. A UV-curable pigment inkjet ink set including a free radical curable ink for inkjet printing according to claim 17 .
20. An inkjet printing system comprising:
the free radical curable ink according to claim 17 in a piezoelectric print head.
21. A packaging material for packaging food comprising:
a cured layer of the free radical curable ink according to claim 17 .
22. A printing method comprising the steps of:
providing the free radical curable liquid as defined by claim 12 ; and
applying a layer of the free radical curable liquid on a substrate; 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.
23. The printing method according to claim 22 , wherein the layer includes a pigment.
24. The printing method according to claim 22 , wherein the layer is a white layer including a titanium dioxide pigment.
25. The printing method according to claim 22 , wherein the layer is a colourless layer present as an outermost layer.
26. The printing method according to claim 22 , wherein the layer is a colourless layer present as a primer.
27. The printing method according to claim 22 , wherein the layer is applied by inkjet printing.
28. The printing method according to claim 22 , wherein the printing method is a single pass printing process using page wide inkjet printing heads or multiple staggered inkjet printing heads which cover an entire width of the substrate.
29. The printing method according to claim 22 , further comprising curing the free radical curable liquid by exposure to actinic radiation from an ultraviolet LED.