Tunable surfactants in dampening fluids for digital offset ink printing applications

Patent metadata

Field	Value
Publication number	US-9713828-B2
Application number	US-201414522015-A
Country	US
Kind code	B2
Filing date	Oct 23, 2014
Priority date	Apr 27, 2011
Publication date	Jul 25, 2017
Grant date	Jul 25, 2017

Abstract

A dampening fluid useful in offset ink printing applications contains water and a surfactant whose structure can be altered. The alteration in structure aids in reducing accumulation of the surfactant on the surface of an imaging member. The surfactant can be decomposed, switched between cis-trans states, or polymerizable with ink that is subsequently placed on the surface.

First claim

The invention claimed is:

1. A method for cleaning an imaging member during offset lithographic printing, comprising:
coating the imaging member with a dampening fluid that comprises water and a surfactant having an alterable structure;
exposing the imaging member to light or heat to alter the structure of the surfactant; and
removing the surfactant from the imaging member, wherein the surfactant is a polymerizable surfactant having the structure of Formula (IV-a);

wherein R c is alkyl containing from 4 to 24 carbon atoms: Ar 1 is aryl having from 6 to 40 carbon atoms; Vn is a hydrocarbon chain having a single carbon-carbon double bond; m is an integer indicating the number of polar groups G on Ar 1 , and is from 1 to 4; and each G is independently a polar group.

2. The method of claim 1 , wherein G contains a polyoxyethylene chain.

3. A method for cleaning an imaging member during offset lithographic printing, comprising:
coating the imaging member with a dampening fluid that comprises water and a surfactant having an alterable structure;
exposing the imaging member to light or heat to alter the structure of the surfactant; and
removing the surfactant from the imaging member, wherein the surfactant is a polymerizable surfactant having the structure of Formula (IV-b):

wherein x has an average value of from 1 to about 50; and
Y is hydrogen or —SO 3 − M + , where M is a cation having a +1 charge.

4. The method of claim 1 , wherein the dampening fluid further comprises a low molecular weight alcohol.

5. The method of claim 4 , wherein the low molecular weight alcohol includes from 1 to 6 carbon atoms and is present in the amount of about 5 wt % to about 35 wt % of the dampening fluid.

6. The method of claim 1 , wherein the water is from 70 wt % to 95 wt % of the dampening fluid.

7. The method of claim 1 , wherein the surfactant is from 0.5 wt % to 2 wt % of the dampening fluid.

8. The method of claim 1 , wherein the dampening fluid further comprises a biocide.

9. The method of claim 1 , wherein the dampening fluid further comprises a sequestrant.

10. The method of claim 1 , wherein the dampening fluid further comprises a corrosion inhibitor.

11. The method of claim 1 , wherein the dampening fluid further comprises a humectant.

12. The method of claim 3 , wherein the dampening fluid further comprises a low molecular weight alcohol.

13. The method of claim 12 , wherein the low molecular weight alcohol includes from 1 to 6 carbon atoms and is present in the amount of about 5 wt % to about 35 wt % of the dampening fluid.

14. The method of claim 3 , wherein the water is from 70 wt % to 95 wt % of the dampening fluid.

15. The method of claim 3 , wherein the surfactant is from 0.5 wt % to 2 wt % of the dampening fluid.

16. The method of claim 3 , wherein the dampening fluid further comprises a biocide.

17. The method of claim 3 , wherein the dampening fluid further comprises a sequestrant.

18. The method of claim 3 , wherein the dampening fluid further comprises a corrosion inhibitor.

19. The method of claim 3 , wherein the dampening fluid further comprises a humectant.

Assignees

• Xerox Corp
• Palo Alto Res Ct Inc

Inventors

• Chopra Naveen
• Odell Peter Gordon
• Ready Steven E
• Peeters Eric
• Stowe Timothy D
• Pattekar Ashish
• Biegelsen David K

Classifications

• B41F7/30

  using spraying elements · CPC title

• B41N3/08

  Damping; Neutralising or similar differentiation treatments for lithographic printing formes; {Gumming or finishing solutions, fountain solutions, correction or deletion fluids, or on-press development (treatment of materials containing silver salts G03F7/063; developers per se for processing photosensitive materials G03F7/32)} · CPC title

• B08B3/10 Primary

  with additional treatment of the liquid or of the object being cleaned, e.g. by heat, by electricity or by vibration · CPC title

• B41P2227/20

  Means enabling or facilitating exchange of tubular printing or impression members, e.g. printing sleeves, blankets · CPC title

• B41F7/24

  Damping devices · CPC title