Belt-driven processes for producing optical effect layers

Patent metadata

Field	Value
Publication number	US-10500889-B2
Application number	US-201515500410-A
Country	US
Kind code	B2
Filing date	Jul 20, 2015
Priority date	Jul 30, 2014
Publication date	Dec 10, 2019
Grant date	Dec 10, 2019

Abstract

The present invention relates to the field of the protection of value documents and value commercial goods. In particular, the invention relates to printing devices and processes for producing optical effect layers (OEL) comprising magnetically oriented magnetic or magnetizable pigment particles. In particular, the present invention provides processes for producing said OELs as anti-counterfeit means on security documents or security articles or for decorative purposes. The printing devices comprise a) an orienting device comprising an orientation means, said orientation means being either a magnetic field generating belt or a non-magnetic belt comprising magnetic field generating elements, said belt being driven by at least two rollers, and b) a hardening unit.

First claim

The invention claimed is:

1. A printing device for producing an optical effect layer on a substrate, the printing device comprising:
a) an orienting device for orienting magnetic or magnetizable pigment particles in a coating composition on the substrate, the orienting device comprising an orientation means, said orientation means being either a magnetic field generating belt or a non-magnetic belt comprising magnetic field generating elements encased within the non-magnetic belt, said belt being driven by at least two rollers; and
b) a hardening unit.

2. The printing device according to claim 1 , further comprising a printing unit arranged to apply a coating composition comprising the magnetic or magnetizable pigment particles in a fluid binder on the substrate.

3. The printing device according to claim 2 , wherein the printing unit is a screen printing unit, a rotogravure printing unit, a flexography printing unit or an intaglio printing unit.

4. The printing device according to claim 1 , wherein the hardening unit comprises one or more radiation sources and/or one or more heaters.

5. The printing device according to claim 1 , wherein the hardening unit is arranged so as to harden the coating composition on the substrate while the substrate is in contact with or otherwise disposed on the orientation means.

6. The printing device of claim 1 , wherein the belt is formed into a loop comprising first and second straight sections each extending between rollers, the printing device being arranged so that the substrate is disposed on at least one of the first and second straight sections while a magnetic field generated by the belt orients the magnetic or magnetizable pigment particles for creating an optical effect layer.

7. A process for producing an optical effect layer on a substrate utilizing the printing device recited in claim 1 , said process comprising the steps of:
a) applying a coating composition comprising magnetic or magnetizable pigment particles and a fluid binder on the substrate, said coating composition being in a first state;
b) exposing the coating composition in the first state to the magnetic field of the orientation means of the printing device, thereby orienting at least a part of the magnetic or magnetizable pigment particles; and
c) hardening by the hardening unit of the printing device the coating composition to a second state so as to fix the magnetic or magnetizable pigment particles in their adopted positions and orientations.

8. The process according to claim 7 , wherein at least a part of the magnetic or magnetizable pigment particles is constituted by optically variable magnetic or magnetizable pigment particles.

9. The process according to claim 7 , wherein the hardening step is carried out by applying heat and/or radiation.

10. The process according to claim 7 , wherein the hardening step c) is carried out partially simultaneously or simultaneously with step b).

11. The process according to claim 7 , wherein the substrate is selected from the group consisting of papers or other fibrous materials, paper-containing materials, glasses, metals, ceramics, plastics and polymers, metalized plastics or polymers, composite materials and mixtures or combinations thereof.

12. An optical effect layer prepared by the process recited in claim 7 .

13. A security document comprising one or more optical effect layer recited in claim 12 .

14. The printing device of claim 6 , wherein the loop is elongate and is comprised of first and second 180° turns defined by rollers at opposed longitudinal ends of the elongate loop and first and second straight sections extending between the opposed turns, one of the straight sections being disposed adjacent the substrate.

15. The process for producing an optical effect layer on a substrate as recited in claim 7 , wherein in step a), the applying of the coating composition is performed using a print unit of the printing device.

16. The process according to claim 8 , wherein the optically variable magnetic or magnetizable pigment particles are selected from the group consisting of magnetic thin-film interference pigment particles, magnetic cholesteric liquid crystal pigment particles, interference coated pigment particles comprising a magnetic material and mixtures of two or more thereof.

Assignees

• Sicpa Holding Sa

Inventors

• Li Xiang
• Schmid Mathieu
• Despland Claude-Alain
• Degott Pierre

Classifications

• B41M3/00

  Printing processes to produce particular kinds of printed work, e.g. patterns ({printing apparatus or machines of special type or for particular purposes B41F17/00;} special designs or pictures per se B44F; manufacturing printed circuits using printing techniques H05K3/12 {; manufacturing organic semiconductor devices using printing techniques H10K71/13}) · CPC title

• B42D25/364

  Liquid crystals · CPC title

• B05D3/207 Primary

  post-treatment by magnetic fields · CPC title

• B05D5/065

  having colour interferences or colour shifts or opalescent looking, flip-flop, two tones · CPC title

• B42D25/369 Primary

  Magnetised or magnetisable materials · CPC title