The most commonly produced and used vinyl-based plastic product is polyvinyl chloride, or PVC. PVC is a versatile, strong, durable plastic that can be formed into many shapes and used for many purposes.
The most common type of vinyl tubing, PVC tubing, is a particularly durable tubing which is resistant to many corrosive solvents and abrasives; it is even sometimes used to transfer hydrocarbons, which are particularly volatile. Vinyl tubing can be an excellent choice for transferring gasses, water and many other liquids because of its capacity to withstand pressure changes. Because vinyl in its unprocessed state is near-transparent, vinyl can be engineered to near transparency, which makes it an excellent choice in applications where close monitoring or measuring of tube contents is important.
Health care applications of tubing, for example, often require easy monitoring of intravenous treatment equipment. Vinyl’s corrosion resistance, combined with its electrical non-conductivity, natural combustion-resistance and non-toxicity make it a good choice for transportation of demanding materials. Vinyl tubing is also used in brewing, pool operation, food processing, waste water management and many other applications.
Like most other plastic tubing products, vinyl tubing is most commonly produced through extrusion. Plastic extrusion is the process by which raw plastic materials are thermoformed (heat formed). The plastic extrusion process begins with a collection of raw plastic material that is placed in a hopper suspended above a conveyance channel. A long screw within the conveyance channel forces the plastic material toward a die.
A die is a specially designed tool that is used to shape raw materials into a usable product. In the case of plastic tube extrusion, the die features a hole and a pin set in a metal plate. The plastic material, which is heated by the friction caused by the turning screw, is forced through the hole in the die, which causes the plastic to take the die’s shape.
The plastic emerges on the other side of the die as plastic tubing, after which it is allowed to cool and harden. At this point, the newly formed tubing is cut to length and prepared for shipping or sent for additional processing. In the case of vinyl tubing, depending on the application, additional processing like coloring may be required. Many tubes are also labeled to allow observers to determine the tubes’ contents easily.