LED-curable offset inks containing aluminum additives
An LED curable lithographic ink comprising: 25-85% of one or more acrylates, wherein at least one acrylate is a pentaacrylate or hexaacrylate; 0-20% of one or more photoinitiators; 5-60% of one or more rosin-modified polyester resins, wherein the rosin-modified polyester resin has a molecular weight of 5,000 to 35,000 Daltons; 0.2-5% of one or more aluminum additives; 0.1-5% of one or more polymerization stabilizers; and 0-50% colorant.
1. A printing ink or varnish composition comprising:
25-85% of one or more acrylates, wherein at least one acrylate is a pentaacrylate or hexaacrylate;
0-20% of one or more photoinitiators;
5-60% of one or more rosin-modified polyester resins, wherein the rosin-modified polyester resin has a molecular weight of 5,000 to 35,000 Daltons;
0.2-5% of one or more aluminum additives;
0.1-5% of one or more polymerization stabilizers; and
0-50% colorant, wherein the rosin-modified polyester resin is derived from i) a gum-rosin, wood rosin or tall oil rosin; ii) one or more difunctional acids or anhydrides; iii) one or more mono-, di-, tri- or tetra-functional polyols; and iv) one or more monofunctional acids.
2. The composition of claim 1 wherein the rosin-modified polyester resin has a molecular weight of 5,000 to 35,000 Daltons, an acid value of 10-30 mgKOH/g and a softening point of 85-110° C.
3. The composition of claim 1 wherein the composition comprises no more than 5% of a vegetable and/or mineral oil.
4. The composition of claim 1 wherein at least one acrylate is a pentaacrylate.
5. The composition of claim 4 , wherein the pentaacrylate is dipentaerythritol pentaacrylate.
6. The composition of claim 1 wherein at least one acrylate is a hexaacrylate.
7. The composition of claim 6 , wherein the hexaacrylate is dipentaerythritol hexaacrylate.
8. The composition of claim 1 , wherein the composition is curable by UV-LED radiation.
9. The composition of claim 1 , wherein the composition comprises 0.5-20% of one or more photoinitiators.
10. The composition of claim 1 , wherein the composition comprises 0% photoinitiators (i.e., the composition is free of photoinitiators) and the composition is curable by electron beam radiation.
11. The composition of claim 1 , wherein at least one of the photoinitiators is selected from the group consisting of thioxantone, an acylphosphine oxide, an aminobenzophenone, an aminoalkylphenones, a ketocumarine or a mixture thereof.
12. The composition of claim 1 , wherein the aluminum additive is selected from the group consisting of an aluminum alkoxide, an aluminum chelate, an aluminum carboxylate or blends thereof.
13. The composition of claim 12 , wherein the aluminum additive is:
(a) an aluminum alkoxide selected from the group consisting of aluminum mono-, di- or tripropoxylate; aluminum mono-, di- or triisopropoxylate; aluminum mono-, di- or tributyrate; aluminum mono-, di- or triisobutyrate, and blends thereof;
(b) an aluminum chelate selected from the group consisting of aluminum mono-ethyl acetoacetate chelate with di-isopropylate; aluminum di- and tri-chelates with alkyl acetoacetate or alkyl diketones, and blends thereof; or
(c) an aluminum carboxylate selected from the group consisting of aluminum tri acetic acid ester or aluminum tri propionic acid ester, and blends thereof.
14. The composition of claim 1 , wherein the aluminum additive is aluminum di-isopropoxide ethyl acetoacetate.
15. The composition of claim 1 , wherein the aluminum additive is in an inert solvent, wherein the inert solvent is selected from a mineral oil or vegetable oil.
16. The composition of claim 1 wherein the rosin-modified polyester resins is derived from i) a gum-rosin, wood rosin or tall oil rosin, ii) one or more difunctional acids or anhydrides selected from maleic acid, maleic anhydride, cyclohexene dicarboxylic acid dianhydride or methyl cyclohexene dicarboxylic acid dianhydride; iii) one or more mono-, di-, tri- or tetra-functional polyols selected from glycerol or trimethylol propane; and iv) one or more monofunctional acids selected from benzoic acid, methyl benzoic acid, tert-butyl benzoic acid, naphthoic acid and linoleic acid.
17. The composition of claim 16 , wherein the rosin-modified polyester resin is derived from i) a gum-rosin or tall oil rosin; ii) one or more difunctional acids or anhydrides selected from cyclohexene dicarboxylic acid dianhydride or methyl cyclohexene dicarboxylic acid dianhydride; iii) one or more mono-, di-, tri- or tetra-functional polyols, selected from glycerol or trimethylol propane; and iv) one or more monofunctional acids selected from benzoic acid, methyl benzoic acid, tert-butyl benzoic acid, naphthoic acid and linoleic acid.
18. The composition of claim 16 wherein the rosin-modified polyester resin is derived from i) a gum-rosin or tall oil rosin; ii) one or more difunctional acids or anhydrides selected from cyclohexene dicarboxylic acid dianhydride or methyl cyclohexene dicarboxylic acid dianhydride; iii) one or more mono-, di-, tri- or tetra-functional polyols, selected from glycerol or trimethylol propane; and iv) benzoic acid.
19. The composition of claim 1 , wherein:
(a) the rosin-modified polyester resin exhibits a molecular weight of 8,000-35,000 Daltons; and/or
(b) the rosin-modified polyester resin has an acid number of 12-25 mg KOH/g.
20. An LED curable offset ink or coating composition which is or which comprises the varnish composition of claim 1 .
21. The composition of claim 1 , exhibiting a ≥5% improvement in ink and press performance score compared to a comparative example without aluminum additive, preferably exhibiting a ≥10% improvement in ink and press performance score compared to a comparative example without aluminum additive, more preferably exhibiting a ≥15% improvement in ink and press performance score compared to a comparative example without aluminum additive.
22. A printed article comprising the composition of claim 1 .
23. A method of preparing printed matter comprising:
applying a composition according to claim 1 to a substrate by offset printing; and
curing the composition by UV-LED or electron beam.
24. A printing ink or varnish composition comprising:
25-85% of one or more acrylates, wherein at least one acrylate is a pentaacrylate or hexaacrylate;
0-20% of one or more photoinitiators;
5-60% of one or more rosin-modified polyester resins, wherein the rosin-modified polyester resin has a molecular weight of 5,000 to 35,000 Daltons;
0.2-5% of one or more aluminum additives;
0.1-5% of one or more polymerization stabilizers; and
0-50% colorant, wherein the rosin-modified polyester resin is derived from i) a gum-rosin, wood rosin or tall oil rosin; ii) one or more difunctional acids or anhydrides; iii) one or more mono-, di-, tri- or tetra-functional polyols; and iv) one or more monofunctional acids; and
wherein the rosin-modified polyester resin has a molecular weight of 5,000 to 35,000 Daltons and/or a softening point of 85-110° C.