Technically, any narrow, long and solid plastic shape is defined as a plastic strip. However, since this is not strict criteria, similar plastic shapes, such as a sheet or a channel, may sometimes also be called a plastic strip. However, when plastic strips are adhered to building components like doors, flooring or windows, they are usually then called trim. In addition, those long and narrow sheets of plastic, found placed in in public places, industrial settings and doorways, keeping heat in or out, are sometimes called strips as well. The choice of how to labels these shapes often goes case-by-case, per an individual’s or organization’s opinion or preference.
No matter the exact nature of the plastic strip, it was most certainly manufactured via a continuous fabrication process, since continuous processes are well-suited to the creation of long strips. Almost always, this fabrication process is the plastic extrusion process. Plastic extrusion begins with the collection of raw plastic material, usually gathered in the form of pellets or flakes, and continues with its placement in a hopper that is suspended above a machine called an extruder. Then, the plastic is released from the hopper into the barrel of the extruder, which contains a shearing screw and is connected to a conveyance channel. The force generated by the shearing screw pushes the plastic into the conveyance channel as the channel turns. The screw also generates friction, which causes the plastic to become molten as it travels down the channel. At this point, some, but not all, plastic extruders will aid in the plasticization process, or the melting of the plastic, through the inclusion of electronic heating elements. At the end of the conveyance channel sits a die, also called a mold/mould or die mold. The die is a precisely designed metal plate through which the molten plastic is forced via a specially cut hole. The shape of the die is predetermined, as the plastic will take its shape as it passes through it. Once the plastic has passed through the die and emerges on the other side, it is considered a plastic strip. Before it undergoes any further processing, it is allowed to cool and harden. After this, it is cut to length and either sent on for shipment or prepped for secondary processing, like labeling or painting.
Shearing screws do a lot of work, and to accommodate these responsibilities, they usually have three sections: the feed zone, the melting zone and the metering zone. The feed zone, which is also called the solids conveying zone, is the region of the screw that feeds the plastic resin into the conveyance channel. The melting zone, alternatively known as the transition zone or the compression zone, is the area in which most of the plastic melts; this is also the area in which the channel narrows significantly, in order to apply pressure to the plastic. Finally, the metering zone, or the melt conveying zone, is the zone in which the last of the plastic particles melt and mix to form molten plastic that is uniform in composition and temperature.
It is important to note that most plastic strip varieties are characterized by their length and width, as well as qualities like weather resistance, strength, durability and other application-relevant qualities. These latter qualities rest largely on the material chosen. For example, plastic strips that will be exposed to large amounts of sunlight will likely be made of polyvinyl chloride, or PVC, a plastic polymer that is highly resistant to UV rays. Acrylics, on the other hand, are frequently selected for their optical clarity. Other common plastic materials used in plastic strip, especially rigid plastic strip, extrusion include: PET, polypropylene, polycarbonate polystyrene, low and high density polyethylene (LDPE and HDPE, respectively), acetal, nylon polyamides and acrylonitrile butadiene styrene (ABS).
Plastic strips are useful for applications in a large number of industries, including: automotives, at-home construction, architecture, industrial construction, furniture and OEM. Specific applications include belting components, vehicle trim, collators for nails in nail guns, building trim, weather strips, window components, door components, vinyl floor tile, edge and wall trim and more. The custom options of these versatile plastic shapes are nearly endless. They may be painted a variety of colors; they may be labeled; they may be coated with any material; they may be cut to any length. Manufacturers looking to enhance their application with plastic strips cannot go wrong. Plastic extrusion is a fairly inexpensive and efficient procedure that can be counted on to make strong, durable pieces.
Plastic Strips – Preferred Plastics, Inc.
Plastic Strips – SFR Industries Inc.
Plastic Strip Informational Video