The plastic resin industry produces resins which are further treated in plastics processing facilities and sold largely to the packaging, building and construction, and consumer markets. Specific product formulations and manufacturing parameters are often kept as trade secrets since the competitiveness of many companies depends on the ability to produce resins with different physical characteristics, such as strength, toughness, and flexibility.
Plastic resins are typically broken down into two categories: thermoplastics and thermosets. Thermoplastic resins are resins that can be heated and molded into shapes repeatedly, while thermoset resins are resins that can be heated and molded only once. Thermoplastic resins dominate plastic resin sales and production.