Printing and Embossing Films

Quarter-wave interference films have seen numerous uses in the field of optical security, due to the strength of reflection and the ability to select numerous colors, and in particular for their observable color shift. Decorative nanolayer quarter-wave polymeric material with more than 100 layers have been known for twenty years, but was not used in the security sector because of their weak iridescent appearance. The 3 M Corporation uses PEN to manufacture reflectors with good band-edge control which are extremely efficient broadband mirrors for communication. These devices are easily noticed by the typical observer and are machine-readable. The PEN quarter-wave mirror films may be fine-line embossed and thinly layered which enliances their appearance [76]. 

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Plastic parts can be post-finished in a number of ways. Film and sheet can be post-embossed with textures and letterpress, gravure, or silk screening can print them. Rigid plastic molded parts can be painted or they can be given a metallic surface by such techniques as metallizing, barrel plating, or electroplating. Another popular method is hot... 

All fabrication techniques presented here are based on the use of toner from office laser printers, which is used to print a layout on a transparency film or a wax paper sheet. The transparency film is essentially used as a poly(ethylene terephthalate) (PET) substrate for polyester-toner (PT) microchannels preparation. The wax paper is used as an initial surface onto which the pattern is printed—the patterns are subsequently transferred either to a recordable compact disks (CD-R) or a glass surface. In either case, this transference is carried out with heat and pressure using the type of heat transfer machine that is used for T-shirt transfer machine or, in more sophisticated form, a tool similar to that used for hot embossing. 

Spanishing n. A printing process similar to valley printing. Ink is deposited on the bottoms and sides of depressed areas of an embossed plastic film. 

This method provides coated fabrics with good flexibility since the polyurethane does not penetrate between the weave of the fabric. The films may be made by extrusion or calendering and a variety of methods are available for bonding the film to the fabric. Solvent and latex adhesives may be used in conjunction with oven or drum laminators and the composites can be embossed and printed. 

Adhesive materials used in vinyl lamination processes are discussed in detail. Characteristics of cold line epoxies and water-based emulsions are discussed. Information is presented on the lamination processes and applying the adhesive. Vinyls most commonly used are said to be Opaque Top Printed Laminate (OTPL)ZKlear View, Opaque Embossed (OE)/Solid Colour Film, Reverse Printed (RP) and Top Printed (TP). 

Drying of latex compounds is usually done in zones to ensure a continuous film. The first zone is typically at about 100 °C to prevent blister formation, the second is at a temperature above that needed for film forming, and the final zone is set at fusion temperature. Fusion is often carried out with an infrared unit. Embossing, if required, is done in line after fusion. Printing of PVC-based films from latex usually requires vinyl resin ink. PVC/acrylic films are more receptive and are printed with a variety of inks. 

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