Resins are chemical compounds having molecular weight more than 300. It is possible to classify natural resins as spirit-soluble and oil-soluble. Oil-soluble resins include rosin, extracted from long-leaf pine turpentine and used in a wide range of applications, including soap making; the toughest natural resin produced in jewellery; Copals used in varnishes; amber; oriental lacquer, derived from a tree native to China; and cashew-nutshell oil, derived from cashew nuts.

Resins have many sources and end uses. Sources can range from natural and synthetic. Resins can derived from polymers, monomers, oils, fatty acids and natural sources.

Perhaps, resins have the widest application areas. From paints and coatings, Personal Care & Home Care, pharma, rubber, plastics and it’s coatings, making electrical and jewelry articles, decorative items, wood coatings etc.

Natural resins have been replaced almost entirely in modern industry by synthetic resins that are divided into two classes, thermoplastic resins that remain plastic after heat treatment, and heat-setting resins that become insoluble and heat-infusible.

Types of Resins

1. Thermoplastic Resins

A substance that softens when heated and when cooled, it hardens again. Thermoplastic product. Product-generic term for certain synthetic or semi-synthetic materials which can be formed or extruded into objects or films or filaments or used for the manufacture of coatings and adhesives. TPA resin, as it is commonly called, comes in liquid form as well as in the form of requires. These are used in plastic coatings as well as in aerosols.
Eg:

• Polyethylene
• Polypropylene
• Polyvinyl chloride
• Chlorinated rubber

So, let us get into the details of some of the Thermoplastic resins

• Alkyd Resins – These are made by heating polyhydric alcohol with polybasic acids. resistance to staining and filtration and electrical and thermal dimensional stability. Due to their inherent advantages, they are used for metal replacements, lenses, safety helmets, insulators and photography film.
• Polycarbonate Resins – These are generally made from bisphenol A and phosgene. With a high refractive index, resistance to staining and filtration and electrical and thermal dimensional stability. Due to their inherent advantages, they are used for metal replacements, lenses, safety helmets, insulators and photography film.
• Polypropylene Resins – These are a type of thermoplastic polymer resin that doesn’t contain BPA. They are colorless, tasteless with a great heat resistance and low density. They also possess a great chemical resistance and are used for toys, pipe and production and coatings.

2. Thermosetting Resins

Thermoplastics and thermoplastic resins are raw, unformed polymers that, when heated, transform into liquid and when chilled, become solid. These can be re-molded and remolded twice, allowing reprocessing of pieces and scraps. TSA, as generally acknowledged as, is used in combination with a melamine resin as baking enamels. In industrial coatings, automotive and two-wheelers, e-rickshaw coatings, brass coatings, etc. are common applications.
Eg:

• Urea
• Formaldehyde resins
• Melamine
• Formaldehyde
• Resins, Phenolic
• Resins (Resol Type)

Let’s explore some of the Thermosetting Resins in details.

• Phenolic Resins –  They are one of the types of thermosetting resins and possess a strong heat and impact resistance to chemical corrosion and moisture penetration. They are used for a variety of products like brake linings, electrical components, molds, adhesive for cements etc.
• Polyester Resins – They are formed by the reaction of polyhydric alcohols and dibasic organic acids. The best thing about it is they have quite an excellent resistance to heat and chemicals. They are quite cost effective and are extensively used for construction, fishing rods, decorative accessories, coatings and in plane and ship components.
• Epoxy Resins – They are a type of reactive prepolymers and polymers belonging to the epoxide group. They have an excellent chemical and heat resistance and great adhesive properties. Used extensively in laminates, linings, propellers and surface coatings.