Resin is a naturally occurring substance that is produced by certain trees. This viscous fluid has been replicated by scientists and is called synthetic resin. Synthetic resins have properties that are extremely similar to their naturally occurring counterparts, most important of which is the ability to harden with the application of heat or pressure, or a combination of both. Products that are created by using synthetic resin include automotive parts, food containers, and pipes.
Synthetic resin is typically manufactured using a chemical polymerization process. This process then results in the creation of polymers that are more stable and homogeneous than naturally occurring resin. Since they are more stable and are cheaper, various forms of synthetic resin are used in a variety of products, such as plastics, paints, varnishes, and textiles.
Generally, synthetic resins are broadly categorized into two areas: thermoplastic synthetic resins and thermosetting synthetic resins. Thermoplastic resins are those that can be softened and reformed through application of heat and pressure, even after being set in a particular shape. The process can be repeated unless the polymeric bonds within the resin are broken. This type of synthetic resin includes polyethylene resin, polypropylene resin, and polyvinyl Chlorine (PVC).
Some of the largest applications for this polymer resin class include packaging films, molded food containers, and molded cup holders. This type of resin is also used extensively for automotive parts that are formed using an injection-molding process. PVC resin is used commonly for pipes and conduits, as well.
Thermosetting synthetic resins are typically softened during the forming stage and are set into their final shape. They then are cured by means of introducing a curing chemical or heat treatment. Once cured into their final shape, thermosetting resins cannot be melted and reformed into a new shape.
The most common type of product in this class of synthetic resins is polyester — also called unsaturated polyester resin. Polyester is widely used in the textile industry for its high-strength fiber-based properties. Another common application for this type of resin is epoxy resin, which is used in industrial materials and construction for its high-strength properties. Polyurethane is another form of this type of resin and is used for a wide variety of products including exterior automotive parts, such as tires and bumpers, as well as for insulation and coating purposes.