Manufacture of security tapes and security threads

DETAILED DESCRIPTION What is claimed is: 1.
A method of manufacturing a laminate structure for use in a security thread or tape comprises: i) providing a first structure having a flexible carrier supporting an optically variable effect structure; ii) adhering the first structure to a flexible substrate with the optically variable effect structure between the carrier and the substrate; iii) removing the carrier; iv) permanently bonding the carrier to the optically variable effect structure to generate a final laminate structure; and, v) slitting the laminate structure from step iv) into at least two lengths.
2.
A method according to claim 1, wherein the optically variable effect structure of the first structure includes a layer which has been embossed on its surface facing away from the carrier and an optical effect enhancing layer on the embossed surface.
3.
A method according to claim 2, wherein the embossed layer is a lacquer.
4.
A method according to claim 3, wherein the lacquer is tinted.
5.
A method according to claim 2, wherein the optical effect enhancing layer comprises metallisation.
6.
A method according to claim 5, wherein the metallisation is patterned or microimaged.
7.
A method according to claim 1, wherein the carrier comprises a plastics material.
8.
A method according to claim 1, further comprising providing a release layer between the carrier and the optically variable effect structure in the first structure.
9.
A method according to claim 1, wherein step ii) comprises providing an adhesive between the optically variable effect structure and the substrate.
10.
A method according to claim 9, wherein the adhesive is provided on the substrate, step ii) comprising bringing the first structure into contact with the adhesive on the substrate and activating the adhesive.
11.
A method according to claim 9, wherein the adhesive comprises hot melt adhesive.
12.
A method according to claim 1, wherein the substrate comprises a plastics material.
13.
A method according to claim 1, wherein the substrate is tinted