PHOTO-CURABLE INK COMPOSITION

• US 20160053124A1
• Filed: 04/03/2014
• Published: 02/25/2016
• Est. Priority Date: 04/04/2013
• Status: Active Grant

• Current Assignee: Hewlett-Packard Industrial Printing Ltd (HP Inc.)
• Original Assignee: Hewlett-Packard Industrial Printing Ltd (HP Inc.)
• Inventors: Brandstein, Or, Trubnikov, Alex, Cohen, Eytan, Lisitsin, Nataly
• Granted Patent: US 9,523,012 B2
• Time in Patent Office: Days
• US Class Current: 1/1
• CPC Class Codes: C08K 3/04 Carbon
• CPC Class Codes: C09D 11/101 Inks specially adapted for printing processes involving curing by wave energy or particle radiation, e.g. with UV-curing following the printing
• CPC Class Codes: C09D 11/322 Pigment inks
• CPC Class Codes: C09D 11/326 characterised by the pigment dispersant
• CPC Class Codes: C09D 11/40 Ink-sets specially adapted for multi-colour inkjet printing

Abstract

A photo-curable ink composition obtained upon mixing a first printing liquid with a second printing liquid. The first printing liquid includes, at least, UV curable polyurethane dispersions and colorant; the second printing liquid includes, at least, hydrophobic radiation-curable monomers, water-soluble or water-miscible radiation curable monomers and photo -initiators. Also disclosed herein is a set of printing liquids including said first and second printing liquid; an inkjet printing system and a method for forming a printed article.

Claims

1. A photo-curable ink composition obtained upon mixing a first printing liquid with a second printing liquid wherein:

a. the first printing liquid includes, at least;

i. UV curable polyurethane dispersions,

ii. and colorant;

b. the second printing liquid includes, at least;

i. hydrophobic radiation-curable monomers,

ii. water-soluble or water-miscible radiation curable monomers,

iii. and photo-initiators.

2. The photo-curable ink composition of claim 1 wherein the first printing liquid includes pigment dispersions as colorant.

3. The photo-curable ink composition of claim 1 wherein the first printing liquid includes water-dispersible acrylic functional polyurethane as UV curable polyurethane dispersions.

4. The photo-curable ink composition of claim 1 wherein the second printing liquid includes water-soluble or water-miscible radiation curable monomers that are ethoxylated tri-methylpropane triacrylates or acrylamides monomers.

5. The photo-curable ink composition of claim 1 wherein the second printing liquid includes hydrophobic radiation-curable monomers that are selected from the group consisting of vinyl caprolactam, hexanediol diacrylate, trimethylolpropane triacrylate and propoxylated neopentyl glycol diacrylate.

6. The photo-curable ink composition of claim 1 wherein the first and/or the second printing liquid(s) further contain(s) one or more additive(s) selected from the group consisting of surfactant, dispersing agent, UV stabilizer, de-foaming agent, rheology modifiers and biocides.

7. The photo-curable ink composition of claim 1 wherein the first printing liquid represents from about 40 to about 75 wt % of the total weight of the obtained photo-curable ink composition.

8. The photo-curable ink composition of claim 1 wherein the second printing liquid represents from about 5 to about 15 wt % of the total weight of the obtained photo-curable ink composition.

9. The photo-curable ink composition of claim 1 wherein the final water content represents from about 10 to about 75 wt % by total weight of the obtained photo-curable ink composition.

10. A set of printing liquids comprising:

a. a first printing liquid that includes, at least, UV curable polyurethane dispersions and colorant;

b. a second printing liquid that includes, at least, hydrophobic radiation-curable monomers, water-soluble or water-miscible radiation curable monomers, and photo-initiators;

wherein said liquids are kept in, at least, two separate devices and form, upon mixing, a photo-curable ink composition.

11. An inkjet printing system comprising:

a) a media substrate;

b) a set of printing liquids such as defined in claim 10;

c) an ink delivery system suitable for using the set of printing liquids;

d) photo energy sources configured to apply photo energy to the obtained photo-curable ink composition once printed on a substrate, said photo energy having a frequency and energy level suitable for pinning, drying and curing the photo-curable ink composition.

12. The inkjet printing system of claim 11 wherein the photo energy source is a UV light source.

13. A method for forming a printed article comprising:

a) providing a media substrate;

b) mixing a first printing liquid containing UV curable polyurethane dispersions and colorant with a second printing liquid containing hydrophobic radiation-curable monomers, water-soluble or water-miscible radiation curable monomers and photo-initiators, in view of obtaining a photo-curable ink composition;

c) projecting of a stream of droplets of said photo-curable ink composition onto the media substrate;

d) pinning said ink composition once printed on the media substrate;

e) drying said ink composition;

f) applying photo energy to the photo-curable ink composition, said photo energy having a frequency and energy level suitable for curing the ink composition.

14. The method for forming a printed article of claim 13, wherein the projection of stream of droplets of ink composition, onto the media substrate, is done via a piezoelectric printhead.

15. The method for forming a printed article of claim 13 further comprising the addition of water to the mixture of the first and second printing liquids into an ink mixing unit, in view of obtaining a photo-curable ink composition.