05-02-2015 дата публикации
Номер: US20150035270A1
The present invention relates to aluminium flakes having a thickness between 7 and 9 nm, coating compositions containing them and the use of the coating compositions for forming (security) products. When the compositions of the present invention are used in coating a hologram the obtained products show an extremely bright OVD image and extremely strong rainbow effect, high purity and contrast. 13-. (canceled)4. A coating composition comprising aluminium flakes having a thickness between 8 and 9 nm and a mean particle diameter D50 of 9 to 10 μm ,wherein the optical density of the aluminium flakes is in the range of 0.16 to 0.24 as measured on the McBeth densitometer, andwherein the aluminium flakes are obtained by vacuum deposition with an operating range of 7 to 9 nm.5. The coating composition according to further comprisinga binder,wherein the ratio of the aluminium flakes to binder is sufficiently high as to permit the alignment of the aluminium flakes to the contours of the diffraction grating.6. The coating composition according to claim 5 , wherein the composition further comprises a solvent.7. The coating composition according to claim 6 , wherein the solvent comprises any one or more of the group comprising an ester claim 6 , a ketone claim 6 , an alcohol claim 6 , an aromatic hydrocarbon and water.8. The coating composition according to claim 5 , wherein the binder comprises any one or more selected from the group consisting of nitrocellulose claim 5 , ethyl cellulose claim 5 , cellulose acetate claim 5 , cellulose acetate propionate (CAP) claim 5 , cellulose acetate butyrate (CAB) claim 5 , alcohol soluble propionate (ASP) claim 5 , vinyl chloride claim 5 , vinyl acetate copolymers claim 5 , vinyl acetate claim 5 , vinyl claim 5 , acrylic claim 5 , polyurethane claim 5 , polyamide claim 5 , rosin ester claim 5 , hydrocarbon claim 5 , aldehyde claim 5 , ketone claim 5 , urethane claim 5 , polyethyleneterephthalate claim 5 , terpene phenol claim 5 , ...
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