Flexible, scratch resistant radiation curable inkjet inks
View Patent ↗A free radical radiation curable inkjet ink containing a photoinitiator and polymerizable compounds includes a) no more than 15 wt % of one or more monofunctional acrylates wherein the homopolymer thereof has a T g smaller than 20° C.; and b) at least 45 wt % of a mixture of monomers consisting of b1) 10 to 45 wt % of a N-vinyl lactam and/or a vinylether acrylate; and b2) 10 to 45 wt % of an ethoxylated and/or propoxylated polyacrylate having a molecular weight of at least 450; wherein all wt % are based on the total weight of the inkjet ink; and wherein the T g is determined by the DSC method in ISO 11357-2:1999.
1. A free radical radiation curable inkjet ink comprising:
a photoinitiator; and
polymerizable compounds including:
a) no more than 15 wt % of one or more monofunctional acrylates wherein a homopolymer thereof has a T g smaller than 20° C.; and
b) at least 45 wt % of a mixture of monomers consisting of:
b1) 10 to 45 wt % of a N-vinyl lactam and/or a vinylether acrylate; and
b2) 10 to 45 wt % of an ethoxylated and/or propoxylated polyacrylate having a molecular weight of at least 450; wherein
all wt % are based on a total weight of the free radical radiation curable inkjet ink; and
the T g is determined by the DSC method in ISO 11357-2:1999.
2. The free radical radiation curable inkjet ink according to claim 1 , wherein the vinylether acrylate is 2-(vinyloxyethoxy)ethyl acrylate.
3. The free radical radiation curable inkjet ink according to claim 1 , wherein the N-vinyl lactam is N-vinyl caprolactam.
4. The free radical radiation curable inkjet ink according to claim 2 , wherein the N-vinyl lactam is N-vinyl caprolactam.
5. The free radical radiation curable inkjet ink according to claim 1 , wherein no monofunctional acrylate having the homopolymer that has a T g smaller than 20° C. is present in the free radical radiation curable inkjet ink.
6. The free radical radiation curable inkjet ink according to claim 2 , wherein no monofunctional acrylate having the homopolymer that has a T g smaller than 20° C. is present in the free radical radiation curable inkjet ink.
7. The free radical radiation curable inkjet ink according to claim 3 , wherein no monofunctional acrylate having the homopolymer that has a T g smaller than 20° C. is present in the free radical radiation curable inkjet ink.
8. The free radical radiation curable inkjet ink according to claim 1 , wherein the N-vinyl lactam and/or vinylether acrylate is present in the free radical radiation curable inkjet ink in an amount between 15 wt % and 30 wt %.
9. The free radical radiation curable inkjet ink according to claim 1 , wherein the ethoxylated and/or propoxylated multifunctional acrylate is present in the free radical radiation curable inkjet ink in an amount between 15 wt % and 30 wt %.
10. The free radical radiation curable inkjet ink according to claim 1 , wherein an amount of all polymerizable compounds is higher than 80 wt % based on the total weight of the free radical radiation curable inkjet ink.
11. The free radical radiation curable inkjet ink according to claim 1 , wherein the free radical radiation curable inkjet ink has a viscosity of less than 20 mPa·s at 45° C. and at a shear rate of 1,000 s −1 .
12. The free radical radiation curable inkjet ink according to claim 1 , further comprising one or more monofunctional acrylates selected from the group consisting of 4-tert.butylcyclohexylacrylate and isobornyl acrylate.
13. The free radical radiation curable inkjet ink according to claim 1 , further comprising a urethane acrylate.
14. The free radical radiation curable inkjet ink according to claim 1 , wherein the free radical radiation curable inkjet ink includes no organic solvent or water.
15. The free radical radiation curable inkjet ink according to claim 1 , wherein the free radical radiation curable inkjet ink is a colorless liquid.
16. A free radical radiation curable inkjet ink set comprising:
at least two different free radical radiation curable inkjet inks according to claim 1 .
17. An inkjet printing method comprising:
a step of inkjet printing a free radical radiation curable inkjet ink as defined by claim 1 on a substantially non-absorbing ink-receiver.
18. An inkjet printing method comprising:
a step of inkjet printing a free radical radiation curable inkjet ink as defined by claim 2 on a substantially non-absorbing ink-receiver.
19. An inkjet printing method comprising:
a step of inkjet printing a free radical radiation curable inkjet ink as defined by claim 3 on a substantially non-absorbing ink-receiver.
20. An inkjet printing method comprising:
a step of inkjet printing a free radical radiation curable inkjet ink as defined by claim 4 on a substantially non-absorbing ink-receiver.
21. An inkjet printing method comprising:
a step of inkjet printing a free radical radiation curable inkjet ink as defined by claim 5 on a substantially non-absorbing ink-receiver.
22. An inkjet printing method comprising:
a step of inkjet printing a free radical radiation curable inkjet ink as defined by claim 6 on a substantially non-absorbing ink-receiver.
23. An inkjet printing method comprising:
a step of inkjet printing a free radical radiation curable inkjet ink as defined by claim 7 on a substantially non-absorbing ink-receiver.