Polymer beads

• US 20020055555A1
• Filed: 09/18/2001
• Published: 05/09/2002
• Est. Priority Date: 09/19/2000
• Status: Active Grant

• Current Assignee: Merck Patent GmbH (Merck & Co., Inc.)
• Original Assignee: Merck Patent GmbH (Merck & Co., Inc.)
• Inventors: Coates, David, Greenfield, Simon, Kuntz, Mathias, Patrick, John
• Granted Patent: US 6,677,042 B2
• Time in Patent Office: Days
• US Class Current: 523/161
• CPC Class Codes: C09D 11/50 Sympathetic, colour changing or similar inks
• CPC Class Codes: C09D 7/65 macromolecular C09D7/41-C09D7/48 take precedence
• CPC Class Codes: C09D 7/68 Particle size between 100-1000 nm
• CPC Class Codes: C09D 7/69 Particle size larger than 1000 nm
• CPC Class Codes: C09K 19/00 Liquid crystal materials
• CPC Class Codes: C09K 19/38 Polymers
• CPC Class Codes: G02B 5/3016 involving passive liquid crystal elements optical properties of liquid crystals G02F1/0063; polarising elements associated with active liquid crystal devices G02F1/133528
• CPC Class Codes: Y10S 428/916 Fraud or tamper detecting
• CPC Class Codes: Y10T 428/249921 Web or sheet containing structurally defined element or component
• CPC Class Codes: Y10T 428/2982 Particulate matter [e.g., sphere, flake, etc.]

Abstract

The invention relates to polymer beads comprising an anisotropic polymer material with helically twisted structure, to their use in reflective films, spraying or printing inks or as pigments, for optical or electrooptical, decorative or security applications, to a reflective film comprising one or more polymer beads in a transmissive binder, and to a security marking or security device comprising one or more polymer beads or comprising a reflective film.

Claims

1. Polymer beads comprising an anisotropic polymer material with helically twisted structure.

2. Polymer beads according to claim 1, having an average diameter from 0.5 to 100 μ

m.

3. Polymer beads according to claim 1, having an average diameter from 1 to 20 μ

m.

4. Polymer beads according to claim 1, wherein the anisotropic polymer material is a linear or crosslinked cholesteric side chain polymer.

5. Polymer beads according to claim 1, wherein the anisotropic polymer material forms a three-dimensional network.

6. Polymer beads according to claim 1, wherein the polymer beads exhibit selective reflection of circularly polarized light, with the central wavelength of reflection being in the range from 200 to 1000 nm.

7. Polymer beads according to claim 6, wherein the reflected wavelength is substantially independent of the viewing angle.

8. Polymer beads according claim 6, wherein the polymer beads reflect either left-handed or right-handed circularly polarized light.

9. Polymer beads according to claim 1, having molecular helices in the anisotropic polymer material which exhibit partial ordering.

10. Polymer beads according to claim 1, which are obtained by emulsion, or suspension, or dispersion polymerization of droplets comprising a polymerizable chiral mesogenic liquid crystal material.

11. A reflective film comprising one or more polymer beads according to claim 1.

12. A reflective film according to claim 11 in a transmissive binder.

13. A reflective film according to claim 11, comprising at least two different polymer beads.

14. A reflective film according to claim 13, wherein the at least two different polymer beads reflect circularly polarized light of different handedness.

15. A security marking or a security device comprising one or more polymer beads according to claim 1.

16. A document comprising a security mark according to claim 15.

17. A spraying or printing ink, or a pigment comprising polymer beads according to claim 1.

18. A cosmetic product comprising polymer beads according to claim 1.

19. An active or passive optical element comprising polymer beads according to claim 1.

20. A plastic comprising polymer beads according to claim 1.