Product designers and engineers have a choice of rotational molding materials for plastics manufacturing. All of these materials are thermoplastics, polymers that become moldable at a specific elevated temperature and that then solidify upon cooling. The advantages of thermoplastics are many and include strength, low processing costs, and manufacturability.
Four of the most common rotational molding materials are LLDPE, HDPE, PP, and static-dissipative PE. Each of these polymers has different properties; however, all of them are easy to mold into strong, hollow plastic products. The following sections describe each of these materials and list some sample applications. For rotomolding that’s supported by expert help with material selection, contact Gregstrom.
LLDPE Plastic for Rotational Molding
Low-density polyethylene (LLDPE) is a durable plastic that combines high tensile strength with good resistance to puncture and impact. The advantages of LLDPE rotomolding include flexible designs, color matching, and support for custom colors. As a rotational molding material, use LLDPE for plastic tanks and bins, buckets and containers, and recreational equipment.
HDPE Plastic for Rotational Molding
High-density polyethylene (HDPE) is a strong, lightweight and relatively inexpensive thermoplastic that can support complex designs and large rotomolded products, such as those used by the food processing industry. Special HDPE grades can meet standards or requirements from the U.S. Food and Drug Administration (FDA) and the U.S. Department of Agriculture (USDA).
PP Plastic for Rotational Molding
Polypropylene (PP) is a durable plastic with a high melting point that can withstand cold temperatures. This thermoplastic material is also resistant to stress but is slightly more prone to cracking than LLDPE. The advantages of PP as a rotational molding material is its resistance to water, detergent, acids, and bases. Applications include toys, material handling, and packaging.
Static-Dissipative PE Plastic for Rotational Molding
Static-dissipative polyethylene (PE) won’t generate a potentially hazardous electrical charge and is recommended for some types of component trays, cart liners, and packaging inserts. Because this thermoplastic provides protection against electrostatic discharge (ESD), static-dissipative PE is used with sensitive electronics. It reduces the risk of a charge and also provides protection against existing charges.
Get Help Choosing the Right Rotational Molding Material
Gregstrom Corporation is a rotomolder in Woburn, Massachusetts (USA) with 75 years of experience. In addition to rotational molding services, we can provide you with design assistance and help with material selection. Our value-added services also include tooling, assembly and testing, quality assurance, finishing, and CNC and robotic routing. When it’s time for your next plastics project, contact us.