Metallic inks composition for digital offset lithographic printing

Patent metadata

Field	Value
Publication number	US-11939478-B2
Application number	US-202016814548-A
Country	US
Kind code	B2
Filing date	Mar 10, 2020
Priority date	Mar 10, 2020
Publication date	Mar 26, 2024
Grant date	Mar 26, 2024

Abstract

The present disclosure is directed to a metallic ink composition for use in digital offset printing, comprising: metallic effect pigment particles, wherein an average equivalent sphere diameter of at least about 90% of the metallic effect pigment particles ranges from greater than 1 micrometer (μm) to 150 μm; at least one dispersant; at least one curable oligomer; and a photo initiator, wherein the metallic ink composition has a viscosity ranging from 150,000 to 1,000,000 millipascal seconds (mPa·s) at 0.1 rad/s at 25° C. Also provided is a method of digital offset printing using the metallic ink composition of the present disclosure.

First claim

What is claimed is:

1. A metallic ink composition for use in digital offset printing, comprising:
metallic effect pigment particles, wherein an average equivalent sphere diameter of at least about 90% of the metallic effect pigment particles ranges from greater than 1 micrometer (μm) to 150 μm;
at least one dispersant;
at least one curable oligomer; and
at least one photo initiator,
wherein the metallic ink composition has a first viscosity ranging from 150,000 to 1,000,000 millipascal seconds (mPa·s) at 0.1 rad/s at 25° C. and a second viscosity ranging from and 85,600 mPa·s at 100 rad/s at 35° C.,
wherein the metallic ink composition further comprises an additional colorant, and wherein the additional colorant is an organic white pigment in an amount ranging from 0 to 5% by weight.

2. The metallic ink composition of claim 1 , wherein the metallic effect pigment particles comprise a substrate and an optically active coating.

3. The metallic ink composition of claim 2 , wherein the optically active coating is selected from the group consisting of metal oxides, metal oxide hydrates, metals, metal fluorides, metal nitrides, metal oxynitrides and mixtures thereof.

4. The metallic ink composition of claim 3 , wherein the metal oxides are selected from the group consisting of titanium oxide, titanium dioxide, aluminum oxide, silicon dioxide, iron oxide, tin oxide, chromium oxide, antimony oxide, cerium oxide and combinations thereof.

5. The metallic ink composition of claim 2 , wherein the optically active coating is selected from the group consisting of titanium dioxide, iron oxide, silicon dioxide and combinations thereof.

6. The metallic ink composition of claim 2 , wherein the substrate comprises a glass flake.

7. The metallic ink composition of claim 1 , wherein the metallic effect pigment particles have an average equivalent spherical diameter D 10 ranging from about 10-20 μm, an average equivalent spherical diameter D 50 ranging from about 25-35 μm and an average equivalent spherical diameter D 90 ranging from about 55-65 μm as measured by laser light scattering.

8. The metallic ink composition of claim 1 , wherein the metallic effect pigment particles have an average equivalent spherical diameter D 10 ranging from about 5-15 μm, an average equivalent spherical diameter D 50 ranging from about 17-27 μm and an average equivalent spherical diameter D 90 ranging from about 37-47 μm as measured by laser light scattering.

9. The metallic ink composition of claim 1 , wherein a determination of the average equivalent sphere diameter comprises laser light scattering.

10. The metallic ink composition of claim 1 , wherein the metallic ink composition further comprises an additional colorant selected from an orange, blue, violet, black, green, yellow and/or red organic pigment, an inorganic pigment and/or a dye.

11. The metallic ink composition of claim 1 , wherein the first viscosity of the metallic ink composition ranges from 150,000 to 200,000 mPa·s at 0.1 rad/s at 25° C.

12. The metallic ink composition of claim 1 , wherein the metallic ink composition further comprises a thermal stabilizer.

13. A method of digital offset printing, which method comprises:
applying a metallic ink composition onto a surface of a re-imageable imaging member, the re-imageable imaging member having dampening fluid disposed thereon;
forming an ink image;
transferring the ink image from the re-imageable surface of the imaging member to a printable substrate;
wherein the metallic ink composition comprises:
metallic effect pigment particles, wherein an average equivalent sphere diameter of at least about 90% of the metallic effect pigment particles ranges from greater than 1 micrometer (μm) to 150 μm;
at least one dispersant;
at least one curable oligomer; and
at least one photo initiator,
wherein the metallic ink composition has a first viscosity ranging from 150,000 and 1,000,000 millipascal seconds (mPa·s) at 0.1 rad/s at 25° C. and a second viscosity ranging from and 85,600 mPa·s at 100 rad/s at 35° C.,
wherein the metallic ink composition further comprises an additional colorant, and wherein the additional colorant is an organic white pigment in an amount ranging from 0 to 5% by weight.

14. The method of claim 13 , wherein the metallic effect particles have an average equivalent spherical diameter D 10 ranging from about 10-20 μm, an average equivalent spherical diameter D 50 ranging from about 25-35 μm and an average equivalent spherical diameter D 90 ranging from about 55-65 μm as measured by laser light scattering.

15. The method of claim 13 , wherein the metallic effect particles have an average equivalent spherical diameter D 10 ranging from about 5-15 μm, an average equivalent spherical diameter D 50 ranging from about 17-27 μm and an average equivalent spherical diameter D 90 ranging from about 37-47 μm as measured by laser light scattering.

16. The method of claim 13 , wherein the first viscosity of the metallic ink composition ranges from 150,000 to 200,000 mPa·s at 0.1 rad/s at 25° C.

17. The method of claim 13 , wherein at least at least 90% of the ink image is transferred to the printable substrate.

18. The method of claim 13 , wherein the printable substrate comprises a non-smooth surface.

19. The method of claim 13 , wherein the printable substrate is selected from the group consisting of textured cardboard, textured plastic and uncoated paper.

20. The method of claim 13 , wherein the metallic effect pigment particles comprise a substrate and an optically active coating, wherein the optically active coating is selected from the group consisting of metal oxides, metal oxide hydrates, metals, metal fluorides, metal nitrides, metal oxynitrides and mixtures thereof.

Assignees

• Xerox Corp

Inventors

• Birau Mihaela Maria
• Allen C Geoffrey
• Magdalinis Aurelian Valeriu

Classifications

• C09D11/037 Primary

  characterised by the pigment · CPC title

• B41C1/10

  for lithographic printing; Master sheets for transferring a lithographic image to the forme {(chemical or electrical pretreatment B41N3/03)}(neutralising or similar differentiation treatments of lithographic printing formes B41N3/08) · CPC title

• B41M1/06

  Lithographic printing · CPC title

• C09C1/0015

  Pigments exhibiting interference colours, e.g. transparent platelets of appropriate thinness or flaky substrates, e.g. mica, bearing appropriate thin transparent coatings · CPC title

• C09C1/0087

  only containing titanium dioxide and silica or silicate · CPC title