Process for a Thermal Transfer of a Liquid Crystal Film Using a Transfer Element

• US 20080261130A1
• Filed: 11/02/2006
• Published: 10/23/2008
• Est. Priority Date: 11/22/2005
• Status: Abandoned Application

• Current Assignee: Merck Patent GmbH (Merck & Co., Inc.)
• Original Assignee: Merck Patent GmbH (Merck & Co., Inc.)
• Inventors: May, Philip Edward, Klein, Sylke, Hammond-Smith, Robert
• Application Number:
  US12/094,509
• Publication Number:
  US 20080261130A1
• Time in Patent Office: Days
• US Class Current: 430/20
• CPC Class Codes: B41M 3/14 Security printing securities B42D25/29
• CPC Class Codes: B41M 5/38207 characterised by aspects not provided for in groups B41M5/385 - B41M5/395
• CPC Class Codes: B41M 5/385 characterised by the transferable dyes or pigments infrared absorbing dyes B41M5/465
• CPC Class Codes: B42D 2033/26 Liquid-crystal material
• CPC Class Codes: B42D 25/00 Information-bearing cards or sheet-like structures characterised by identification or security features; Manufacture thereof printing processes to produce identification or security features B41M3/14
• CPC Class Codes: B42D 25/29 Securities; Bank notes
• CPC Class Codes: B42D 25/364 Liquid crystals
• CPC Class Codes: B42D 25/41 using electromagnetic radiation B42D25/435 takes precedence
• CPC Class Codes: C09K 19/38 Polymers
• CPC Class Codes: C09K 19/3852 Poly(meth)acrylate derivatives
• CPC Class Codes: C09K 2219/03 in the form of films, e.g. films after polymerisation of LC precursor

Abstract

The invention relates to a laser-induced process that employs a transfer element comprising a liquid crystal material for a thermal transfer onto a receiving surface. The process is suitable for generating markings with various appearance or optical effects on a surface of choice. The transfer element comprises a light-to-heat conversion layer and a transfer layer The transfer layer comprises a liquid crystal material, especially a liquid crystal polymer film.

Claims

1. A transfer process for forming a marking on a surface comprising the steps of

a) providing a transfer element comprising a light-to-heat conversion layer and a transfer layer comprising a liquid crystal material,

b) placing the transfer element onto a receiving surface with the transfer layer directed to the surface

c) irradiating the assembly selectively with a radiation source in a manner effective to transfer portions of the transfer layer corresponding to the irradiated areas onto the surface.

2. Process according to claim 1 wherein the radiation source is a laser beam.

3. Process according to claim 1 wherein the liquid crystal material comprised in the transfer layer comprises a cross-linked liquid crystal material.

4. Process according to claim 1 wherein the transfer layer additionally comprises a resin.

5. Process according to claim 1 wherein the resin is a thermoplastic resin.

6. Process according to claim 1 wherein the transfer layer is prepared by spreading a composition comprising

one or more polymerisable mesogens,

a resin, and

a polymerisation initiator

onto a substrate and polymerising it.

12. Polymeric liquid crystalline marking on a surface formed by a process according to claim 1.

13. Use of a polymeric liquid crystalline marking formed by a process according to claim 1 for security applications, identification, labelling, counterfeit prevention or decoration.

14. A data carrier or document of value comprising a marking according to claim 12.

7. A thermal transfer element comprising at least

a light-to-heat conversion layer, and

a transfer layer, comprising at least a liquid crystal material.

8. A transfer element according to claim 7 wherein the transfer layer comprises 1-15% of one or more resins.

9. A transfer element according to claim 7,

wherein the thermal transfer layer comprises at least 30% of one or more cross-linked liquid crystalline components.

10. A transfer element according to claim 7,

wherein the light-to-heat conversion layer is a radiation absorbing polymeric substrate or a non-reflecting metal foil.

11. Composition for forming a liquid crystalline thermal transfer layer comprising at least

one or more polymerisable mesogens,

a resin, and

a polymerisation initiator.