Hologram printing on paper or cardboard at high speeds - has varnish layer on web print material to be hardened by UV setting

摘要

To apply holograms etc. to printing paper and cardboard, at least the varnish layer to hold the microstructure can be set by radiation, esp. by UV. Varnish is set from the matrix side and through the matrix, which is transparent to radiation, through the plate cylinder or matrix carrier. Pref. varnish layer is hardened before the print material in contact with the matrix is removed. On rotary printing, the varnish layer is hardened by radiation while it rotates round the plate cylinder, and through the cylinder wall from an inner radiation source, providing ultraviolet or electron beam heat. Shaping matrix is a single matrix, continuous belt loop, a cylinder or cylinder sleeve. Shaping medium has 0.2-2.0 wt.% of a separator to release the hardened forming medium and prevent clamping of the holographic positive/negative fine structure, with a chemical which has greater adhesion to the print material than to the matrix. Print material is a clear or opaque plastics film or paperweb, or polyester paper, a fabric and pref. a dimensionally stable fine woven plastics. Material can also be a smooth film which acts as a carrier during the shaping and hardening stages to give a self supporting film to hold the microstructure and be rolled. Heat activated separator is applied to the polyester carrier followed by a radiation setting varnish layer. Separator contains wax or Si. After the hologram structure has been shaped, a reflective metallising is applied over the varnish to be covered by a transparent protective layer which is set by pref. UV radiation. Reflective metal layer can be applied before the hologram structure is formed and inserted into a second varnish layer. ADVANTAGE - Cheap and direct application of holograms and other fine structures to paper or cardboard or opaque film, at high printing speeds.