Synthetic resins are materials with a property of interest that is similar to natural plant resins: they are viscous liquids that are capable of hardening permanently. Otherwise, chemically they are very different from the various resinous compounds secreted by plants. Synthetic resins comprise a large class of synthetic products that have some of the physical properties of natural resins but are different chemically. Synthetic resins are not clearly differentiated from plastics.
In modern industry natural resins have been almost entirely replaced by synthetic resins, which are divided into two classes, thermoplastic resins, which remain plastic after heat treatment, and thermosetting resins, which become insoluble and infusible on heating. Thermoplastic resin softens repeatedly by heating. Thermosetting resin, on the other hand, hardens only once when heated. Thermoplastics produced by the local industry include Polystyrene (PS), Polyvinyl Chloride (PVC), Alkyds and Polyester Fiber, while those of thermosetting resins include Phthalic Anhydride, Aluminum Paste Resin, Adhesive Resin, Acrylic Resin Urea- and Phenol-Formaldehyde, and Colored Pellets.
For more detailsdownload PDF file.