Plastics We Rotationally Mold

Linear Polyethylene (LLDPE, MDPE, and HDLPE)

The Linear Polyethylene Family is the most widely used group of plastics for rotational molding. These plastics are economical, tough, have wide chemical compatibility and are easily molded. Polyethylene is easily colored and a long-term UV protection package is standard. HDLPE is not actually a correct term but it provides a good shorthand for High Density Polyethylene that is from the linear family and not Cross-linked.

Polypropylene

This polymer is an engineering plastic that is often selected due to its thermal properties. Polypropylene can handle continuous use temperatures up to 200 F. Polypropylene can be joined with thermoplastic welding. Unlike other plastic tanks, the inside surface of rotationally molded Polypropylene tanks may not be smooth. The integrity of the tank is not in doubt but there may be variation in thicknesses, especially on large tanks.

Polyvinylidene Fluoride (PVDF)

Kynar is specialty plastic that is used in high purity applications. It can handle temperatures up to 300 F. and is very resistant to most acids and bases. PVDF can be joined with thermoplastic welding.

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We also Combine Materials

There are times when it makes sense to make multi-layer parts. As an example, we can make HDPE tanks with an inner layer of PVDF. This gives a container with the chemical resistance of PVDF without the cost of a container made entirely of PVDF. We can make multi-layer parts with layers of each of the materials we mold. In addition to layering the different materials, we can also mold in a layer of linear polyethylene foam against a linear polyethylene wall. Contact us for details if you have an application that could benefit from multi-layer molding.