Production process of transparent holographic film with high refractive index

Abstract

The invention discloses a production process of a transparent holographic film with high refractive index, and belongs to the technical field of laser anti-counterfeit. The process comprises the steps of preparation of film coating liquid with high refractive index, coating of the film coating liquid with high refractive index, low-temperature film formation and UV precuring of the film coating liquid, wired mold pressing, UV light complete curing and rolling of the transparent holographic film. The production process combines an information layer with a medium layer through the film coating liquid with high refractive index to form a composite coating layer, so that the prepared transparent holographic film has such characteristics as high refractive index, high transparency and signal-to-noise ratio, excellent wear resistance and ageing resistance and obvious holographic image contrast, the technical bottlenecks of difficult tracking and difficult positioning caused by small contrast in traditional transparent holographic images are broken through, the random positioning of the transparent holographic images in certificates is truly realized, and the transparent holographic comprehensive anti-counterfeiting effect is promoted.

Description

technical field [0001] The invention relates to a production process of a transparent holographic film with a high refractive index, belonging to the technical field of laser anti-counterfeiting. Background technique [0002] At present, conventional optical holographic films are generally composed of functional coatings such as a plastic base layer, a separation layer, an information layer, a dielectric layer, and a printed rubber layer. In the preparation process, the separation layer is first coated on the plastic base layer, and then the information layer is coated on the separation layer, and then the plastic film coated with the separation layer and the information layer is molded on a molding machine, and the holographic pattern is embossed on the On the information layer, and on the information layer printed with holographic patterns, a dielectric layer is coated, or an offset printing layer is applied, so as to prepare an optical holographic film capable of displayi...

AI Technical Summary

Problems solved by technology

For transparent holographic films, transparent materials such as zinc sulfide and titanium dioxide must be selected as the dielectric layer to obtain transparent holographic patterns. However, the transparent inorganic dielectric layer is greatly affected by the high-temperature evaporation process, and the uniformity is difficult to control. The transparency of the coating is poor, and the existence of the transparent medium coating, there are two interfaces: the information layer / medium layer (the first interface) and the medium layer / printing layer (the second interface), which may result in the first The diffraction pattern of the interface is interfered by the diffraction pattern of the second interface, so that the technical indicators such as diffraction efficiency and signal-to-noise ratio of the transparent optical holographic film are lower than those of the aluminum-coated holographic film

[0005] In addition, molded laser holography technology is a grating preparation technology for optical holographic films, but this technology requires high temperature (about 150°C) and high pressure production conditions, which will lead to thermal shrinkage deformation of the film, loss of transparency and information distortion

The above factors will eventually lead to transparent holographic films lower than non-transparent holographic films such as aluminized holographic films and holographic hot stamping foils in terms of diffraction efficiency, signal-to-noise ratio and other technical indicators.

[0006] To sum up, the current coating design of transparent holographic film is still unable to break through the technical difficulties caused by the decline of diffraction performance of transparent holographic film, the original multi-interface coating structure, high temperature evaporation and molding, which greatly limits the application of transparent holographic film. Research and Application

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