Extruder coating and lamination

Many different processes are used to coat or laminate there are literally hundreds of different processes used just to coat materials (Table 5.4) (Chapter 10). An important coating method involves the extruder, particularly for long runs. The extruded dedicated fast lines are used since they provide quality controlled products and are very cost effective. 

Three processes are used to enhance certain properties of films (1) orientation, (2) coating, and (3) lamination. These special processes are usually incorporated into the main manufacturing processes of casting, extruding, and calendering. 

Thermoset Phenolic Sheet, Paper Reinforced Adhesive Coated, Paper-Backed, Plastic Sheet Thermosetting Resins Cast from Monomers Sheet and Rods Scribe-Coated Plastic Sheet Tracing, Glazed and Matte Finish Plastic Sheet FEP Fluorocarbon Extruded Sheet and Film Polyethylene, Laminated, Nylon Reinforced Sheet Styrene-Butadiene Sheet... 

The partially esterified acetate, propionate, and butyrate esters of cellulose also have proved to be useful. They can be made with a wide range of properties because of the latitude provided by varying molecular weight, ester content, and amount and type of plasticizer. The cellulose esters have been made into fiber, thickeners for coatings, and molded articles such as toys, combs, eyeglass frames, and cutlery handles. They have been extruded into pipe, formed into sheet, and used for a variety of decorative and protective laminates. 

Dry Paint Film laminate is a composite of a continuous cast polyvinyl-idene difluoride (PVDF) coating that is air dried and laminated to an extruded gel-free thermoplastic backing sheet. The thickness of the thermoplastic sheet varies by application process and is generally composed of either TPO or ABS. 

The process of laminating single-layer web materials to give flexible multilayer film structures has been an established method for many years. Alternate production techniques include extrusion coating and co-extrusion, where plastics are melted and extruded in thin layers through an extrusion die. 

Recent trends in protective coatings used on buried pipelines have been away from reinforced hot applied coal tar and asphalt enamels and butyl rubber laminate tapes, particularly where applied over-the-ditch . The more recently developed coatings based on fusion bonded epoxies, extruded poly-ethylenes, liquid-applied epoxies and polyurethanes, require factory application where superior levels of pipe preparation and quality control of the application process can be achieved. 

Instead of the simultaneously extmded polymer film, a pre-extmded or laminated film can be laminated on the substrate (e.g., paper or paper board). In this case, the extruder can be used to extrude the polymer providing adhesion (e.g., Ecoflex ) in a thin layer between the polymer coating film or laminate and the substrate. Another option is to apply a dispersion or heat in the laminator (Fig. 10, 4) to obtain adhesion. After thickness measurement and second subsequent corona treatment, substrate and polymer coating are wound on a winder (Fig. 10, 6) in order to obtain rolls for transport to subsequent processes (e.g., printing, cutting, cup forming, box making). 

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