Hyperbranched ink compositions for controlled dimensional change and low energy curing
View Patent ↗Disclosed herein are ink compositions including at least one hyperbranched oligomer present in an amount ranging from about 3% to about 20% and having a functionality ranging from about 6 to about 40; at least one pigment present in an amount of at least about 10%; and at least one photoinitiator present in an amount ranging from 5% to 10%. Further provided herein are methods of printing using a variable data digital lithographic printing device.
1. An ink composition comprising:
at least one hyperbranched oligomer present in an amount ranging from about 3 wt % to about 20 wt % and having a functionality ranging from about 10 to about 20;
at least one pigment present in an amount of at least 10%;
at least one photoinitiator present in an amount ranging from about 5% to about 10%; and
at least one rheology modifier chosen from organoclays, attapulgite clays and bentonite clays,
wherein the ink composition has a viscosity ranging from about 5,000 cP to about 300,000 cP at 25° C. and a shear rate of 5 sec −1 , and
wherein the ink is a digital offset ink.
2. The ink composition of claim 1 , further comprising at least one ingredient chosen from acrylate monomers, dispersants, and UV stabilizers.
3. The ink composition of claim 1 , wherein the at least one pigment is present in an amount of at least 15% based on the total weight of the ink composition.
4. The ink composition of claim 1 , wherein at least one pigment is a black pigment.
5. The ink composition of claim 1 , wherein the at least one hyperbranched oligomer is chosen from polyester acrylates.
6. The ink composition of claim 1 , wherein the at least one hyperbranched oligomer has a functionality of 16.
7. The ink composition of claim 1 , wherein the at least one hyperbranched oligomer is chosen from polymers of Formulae I and II:
wherein A is an acrylate group
or a methacrylate group
and the linear and branched segments are chosen from alkyl, ether, branched ether, ester, branched ester, amide, azine, triazine, isocyanurate, and tris-isocyanurate groups.
8. The ink composition of claim 1 , wherein the at least one hyperbranched oligomer is present in the ink composition in an amount of about 5 wt % to about 10 wt %.
9. The ink composition of claim 1 , wherein the at least one pigment is chosen from black pigments, red pigments, blue pigments, cyan pigments, magenta pigments and yellow pigments.
10. The ink composition of claim 1 , wherein the at least one pigment is not a white pigment.
11. The ink composition of claim 1 , wherein the ink composition has a double methyl ethyl ketone (MEK) rub test value of at least 70 rubs.
12. An ink composition comprising:
at least one hyperbranched oligomer present in an amount ranging from about 3 wt % to about 20 wt % and having a functionality ranging from about 10 to about 20;
at least one pigment present in an amount of at least 10%;
at least one photoinitiator present in an amount ranging from about 5% to about 10%; and
at least one rheology modifier chosen from organoclays, attapulgite clays, bentonite clays, and modified hydrogenated castor oils,
wherein the ink composition has a viscosity ranging from about 5,000 cP to about 300,000 cP at 25° C. and a shear rate of 5 sec −1 , and
wherein the ink is a digital offset ink.
13. The ink composition of claim 12 , wherein the at least one pigment is chosen from black pigments, red pigments, blue pigments, cyan pigments, magenta pigments and yellow pigments.
14. The ink composition of claim 12 , wherein the at least one pigment is not a white pigment.