Plastic films are used in a wide variety of applications, from paper bag linings to food packaging.
Plastic film
is often used as a lining material for paper bags and sacks to pack many dry products. It has been reported that such coatings, usually electrical insulators, can create new electrostatic hazards where they did not exist before. As the contents of the bag slide out, the liner loads and, if it protrudes partially into the grounded hopper, a discharge may occur.Several such incidents have been reported, with some involving injuries to plant operators. The bags cannot be grounded, so other methods must be used to protect workers. In the past, serious explosion incidents involving larger bags and lined bags have prompted the development of a new class of synthetic fabric materials that weave semiconductive fibers into the fabric and provide a base for the fibers (Wurr, 199). The bags made with these new fabrics (flexible intermediate bulk containers or FIBC) are useful for dissipating static electrical charge and, at the same time, minimizing any risk of capacitive sparks.
Plastic film can be used and applied to a multitude of applications, such as food packaging, protective packaging or the protection of agricultural crops. Polymer additives are critical to the performance of the plastic film for such applications. Incorporating the right type and level of additive can increase performance and reduce waste by alleviating a number of processing, handling and storage problems that occur during the production stages of plastic films. Plastic films can also change shape due to the adsorption of small molecules, particularly water molecules.
Next, a plastic film (coating) is glued with adhesive to the engraved copper circuits, except that areas are left open for later joining the components. As such, the biaxial orientation of plastic films represents a refinement process that is applicable to almost all plastics. Plastic film is defined as a continuous form of plastic material, which is thin and is generally wound into a core or cut into sheets. Metal-looking plastic film is very common in food bags, such as those used to protect candies and chips.
Plastic films can be produced from a variety of types of polymers, including polyolefins, polyesters and biopolymers. Calendering is a method of producing plastic films and sheets by squeezing plastic across the space (or “line of contact”) between two counter-rotating cylinders. Grafix Plastics has a wide selection of transparent plastic films and sheets, in different polymers, thicknesses and sizes. In the molten film process, the plastic leaves the extruder through a slit-shaped matrix, producing a thin plastic film. The packaging of peppers with plastic films extended their shelf life; however, it seemed that the main benefit was mediated by maintaining high relative humidity inside the package, which reduced perspiration rates (Maxie et al.).
