OPTICALLY VARIABLE SECURITY THREADS AND STRIPES

• US 20160325578A1
• Filed: 12/11/2013
• Published: 11/10/2016
• Est. Priority Date: 12/11/2013
• Status: Active Grant

• Current Assignee: China Banknote Sicpa Security Ink Co., Ltd, Sicpa Holding SA
• Original Assignee: China Banknote Sicpa Security Ink Co., Ltd, Sicpa Holding SA
• Inventors: RITTER, Gebhard, DEGOTT, Pierre, LI, Xiang, YUAN, Fang
• Granted Patent: US 10,166,808 B2
• Time in Patent Office: Days
• US Class Current: 1/1
• CPC Class Codes: B42D 25/29 Securities; Bank notes
• CPC Class Codes: B42D 25/324 Reliefs
• CPC Class Codes: B42D 25/328 Diffraction gratings; Holograms
• CPC Class Codes: B42D 25/342 Moiré effects
• CPC Class Codes: B42D 25/351 Translucent or partly translucent parts, e.g. windows
• CPC Class Codes: B42D 25/355 Security threads
• CPC Class Codes: B42D 25/369 Magnetised or magnetisable materials
• CPC Class Codes: B42D 25/373 Metallic materials
• CPC Class Codes: B42D 25/378 Special inks
• CPC Class Codes: B42D 25/45 Associating two or more layers

Abstract

Optically variable security threads or stripes to be incorporated into or onto security documents, relate to the field of the protection of value documents and value commercial goods against counterfeit and illegal reproduction. The security threads or stripes comprise a) an optically variable layer; b) a color constant layer having a color matching the color impression of the optically variable layer at a viewing angle; c) a holographic metallic layer; and d) and a transparent substrate, wherein the optically variable layer, the color constant layer and the holographic metallic layer are at least partially jointly visible from at least one side of the security thread or stripe.

Claims

1. A security thread or stripe comprising:

a) an optically variable layer imparting a different color impression at different viewing angles and being made of an optically variable composition comprising from about 2 to about 40 wt-% of optically variable pigments, said optically variable layer comprising one or more gaps in the form of indicia or consist of indicia made of the optically variable composition, the weight percents being based on the total weight of the optically variable composition;

b) a color constant layer having a color matching the color impression of the optically variable layer at a viewing angle, and being made of color constant composition comprising from about 1 to about 20 wt-% of one or more dyes and/or from about 0.1 to about 45 wt-% of inorganic pigments, organic pigments or mixtures thereof, said color constant layer either comprising one or more gaps in the form of indicia or consist of indicia made of the color constant composition, the weight percents being based on the total weight of the color constant composition;

c) a holographic metallic layer; and

d) a transparent substrate

wherein i) the holographic metallic layer faces the environment and faces the transparent substrate and is present on the opposite side of the substrate carrying the color constant layer and the optically variable layer and ii) the color constant layer and/or the optically variable layer faces the environment, and

wherein the optically variable layer, the color constant layer and the holographic metallic layer are at least partially jointly visible from at least one side of the security thread or stripe.

2. The security thread or stripe according to claim 1, wherein the optically variable layer is on top of the color constant layer.

3. The security thread or stripe according to claim 1, wherein the color constant layer is on top of the optically variable layer.

4. The security thread or stripe according to claim 1, wherein the optically variable layer is adjacent to the color constant layer.

5. The security thread or stripe according to claim 1, wherein the transparent substrate is made of one or more plastics or polymers, preferably selected form the group consisting of polyolefins, polyamides, polyesters, polyvinylchlorides and mixtures thereof.

6. The security thread or stripe according to claim 1, wherein the optically variable pigments are selected from the group consisting of thin film interference pigments, magnetic thin film interference pigments, interference coated pigments, interference coated pigment particles comprising a magnetic material, and mixtures thereof.

7. The security thread or stripe according to claim 1 further comprising one or more protective layers and/or one or more additional transparent substrates made of one or more plastics or polymers, preferably independently selected form the group consisting of polyolefins, polyamides, polyesters, polyvinylchlorides and mixtures thereof.

8. The security thread or stripe according claim 7, wherein the one or more protective layers and/or the one or more additional transparent substrates face the holographic metallic layer described herein and face the environment and/or wherein the one or more protective layers and/or the one or more additional transparent substrates face the optically variable layer and/or the color constant layer and face the environment.

9. The security thread or stripe according to claim 1 further comprising one or more additional layers selected from the group consisting of adhesive layers, lacquers, machine readable layers, hiding layers and combinations thereof.

10. The security thread or stripe according to claim 1, wherein the indicia are independently selected from the group consisting of symbols, alphanumeric symbols, motifs, geometric patterns, letters, words, numbers, logos, drawings and combinations thereof.

11. A process for making the security thread or stripe recited in claim 1 comprising the steps of:

a) providing the transparent substrate comprising the holographic metallic layer,

b) either b1) applying the color constant composition onto the transparent substrate on the opposite side of the substrate carrying the holographic metallic layer so as to form the color constant layer by a process selected from the group consisting of offset, rotogravure, screen printing, flexography and combinations thereof either while keeping one or more gaps in the form of indicia or by applying the color constant composition in the form of indicia and hardening said color constant composition; and

applying the optically variable composition on the same side of the substrate carrying the color constant layer so as to form the optically variable layer by a process selected from the group consisting of rotogravure, screen printing, flexography and combinations thereof either while keeping one or more gaps in the form of indicia or by applying the optically variable composition in the form of indicia and hardening said optically variable composition, or

b2) applying the optically variable composition onto the transparent substrate on the opposite side of the substrate carrying the holographic metallic layer so as to form the optically variable layer by a process selected from the group consisting of rotogravure, screen printing, flexography and combinations thereof either while keeping one or more gaps in the form of indicia or by applying the optically variable composition in the form of indicia, and hardening said optically variable composition; and

applying the color constant composition on the same side of the substrate carrying the optically variable layer so as to form the color constant layer by a process selected from the group consisting of offset, rotogravure, screen printing, flexography and combinations thereof either while keeping one or more gaps in the form of indicia or by applying the color constant composition in the form of indicia and hardening said color constant composition;

c) optionally c1) applying one or more additional transparent substrates on the structure obtained under step b), and/or c2) applying one or more protective varnishes so as to form one or more protective layers; and

d) optionally applying one or more thermoadhesive layers on one or both sides of the structure obtained under step b) or c).

12. A process for making a security thread or stripe recited in claim 1 further comprising one or more additional transparent substrates, said process comprising a step of laminating a first structure comprising the transparent substrate and the holographic metallic layer with a second structure comprising one or more additional transparent substrates, the optically variable layer and the color constant layer, wherein the optically variable layer and the color constant layer are placed between the transparent substrate and the one or more additional transparent substrate and wherein the holographic metallic layer faces the environment.

13. A use of the security thread or stripe recited in claim 1 for the protection of a security document against counterfeiting, fraud or illegal reproduction.

14. A security document comprising a security thread or stripe recited in claim 1.

15. A process for producing the security document recited in 14, said process comprising the steps of:

i) producing the security thread or stripe, and

ii) at least partially embedding in said security document the security thread or stripe obtained under step a) or mounting the security thread or stripe obtained under step a) on the surface of the security document.