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OwnerDavid Malcolm Lewis, Peter Jeffrey Broadbentinventors
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Abstract
An image article comprises a substrate having a security image coated on at least a portion thereof, which security image effects less than 50% reflectance of radiation of a wavelength between 800 and 900 nm, wherein the security image comprises a defined infrared-absorbing compound, for example Pigment Green 8, wherein said infrared-absorbing compound does not create a strongly coloured security image.
Claims14
An image article comprising a substrate having a security image coated on at least a portion thereof, which security image effects less than 50% reflectance of radiation of a wavelength between 800 and 900 nm, wherein the security image comprises an infrared-absorbing compound selected from:
- or a salt or polymer thereof, wherein
- M is a metal selected from a group 3-10 (Group IIIB-VIII) element or a lanthanide;
- R1 is selected from hydrogen, phosphonate, sulphonate, nitro, halo, cyano, thiocyano, thioalkyl, thioaryl, alkyl, alkoxy, aryl, aryloxy, amines, substituted amines and substituted aryl;
- one of R2 and R3 is oxygen and the other of R2 and R3 is NO;
- n is a number corresponding to half the co-ordination number of the metal M;
- each L and L′ is independently a ligand complexed to the metal M;
- and
- y is a number corresponding to the co-ordination number of the metal M;
- wherein said infrared-absorbing compound does not create a strongly coloured security image.
(A method of manufacturing an image article comprising the steps of:
- (a) providing a substrate;
- and
- (b) image-wise coating an infra-red absorbing compound selected from:
- or a salt or polymer thereof, onto at least a portion of the substrate to form a security image which is not strongly coloured and which effects less than 50% reflectance of radiation of a wavelength between 800 and 900 nm, wherein:
- M is a metal selected from a group 3-10 (Group IIIB-VIII) element or a lanthanide;
- R1 is selected from hydrogen, phosphonate, sulphonate, nitro, halo, cyano, thiocyano, thioalkyl, thioaryl, alkyl, alkoxy, aryl, aryloxy, amines, substituted amines and substituted aryl;
- one of R2 and R3 is oxygen and the other of R2 and R3 is NO;
- n is a number corresponding to half the co-ordination number of the metal M;
- each L and L′ is independently a ligand complexed to the metal M;
- and
- y is a number corresponding to the co-ordination number of the metal M.
The use of a compound of formula:
- or a salt or polymer thereof, coated on at least a portion of the substrate, as an infrared radiation-absorbing additive in a security image coated on a substrate of an image article, wherein:
- M is a metal selected from a group 3-10 (Group IIIB-VIII) element or a lanthanide;
- R1 is selected from hydrogen, phosphonate, sulphonate, nitro, halo, cyano, thiocyano, thioalkyl, thioaryl, alkyl, alkoxy, aryl, aryloxy, amines, substituted amines and substituted aryl;
- one of R2 and R3 is oxygen and the other of R2 and R3 is NO;
- n is a number corresponding to half the co-ordination number of the metal M;
- each L and L′ is independently a ligand complexed to the metal M;
- and
- y is a number corresponding to the co-ordination number of the metal M;
- wherein said security image is not strongly coloured.
Dependencies are inferred from the claim text.