Plastics

Plastics are generally classified into two categories: thermoplastics and thermosets. Thermoplastics melt when heated, allowing them to be reshaped and solidified upon cooling—making them recyclable and versatile. Common thermoplastics include polyethylene, polypropylene, PVC, polystyrene, nylon, and polycarbonate. These are often produced as pellets for further processing. Within the industry, plastics are also categorized as commodity resins, which are low-cost and high-volume (e.g., PET, polypropylene), or specialty resins, which are engineered for specific applications and produced at lower volumes and higher costs. Specialty resins include engineering plastics like polyacetal, nylon, Teflon, and polycarbonate, which are used in demanding applications such as automotive and plumbing. Thermosets, on the other hand, permanently harden after molding and include materials like vulcanized rubber, acrylics, polyurethanes, and epoxies.

Handling plastic resins, whether pellets, flakes, or powders, requires specialized equipment to ensure smooth flow and effective dust control. Bulk bag dischargers should include accessories that stretch and elongate the bags to eliminate trapped material and promote consistent flow. Dust-tight seals and integrated dust collectors help contain airborne particles during discharge. Receiving hoppers must be properly vented and may require vibrators to assist flow, especially for resins that do not flow freely. For smaller packaging, bag dump stations with filtration systems are ideal. Conveying systems must be tailored to the resin’s properties. For example, flexible screw conveyors require the correct screw type to handle specific flow behaviors, and pneumatic systems must be carefully designed to reduce wear and prevent issues such as streamers or angel hair. To reduce friction and heat buildup, which can degrade resin quality, deflection elbows are recommended to preserve material integrity and protect downstream equipment.