Rotational Molding

Rotational molding, or rotational moulding, is a process for making hollow parts. Plastic powder is added to a mold which is clamped shut. In more traditional rotational molding methods, the mold is sent to an oven where it rotates biaxially to slowly lay the powder against the mold wall in a layer-by-layer fashion. The powder continues to melt and densify until the mold is removed from the oven to cool and then the hollow part is removed.

Rotational molding resins can be used to manufacture parts for lawn and garden equipment, heavy duty equipment, construction equipment, agricultural equipment, furniture and marine applications.

Some of the most common products made from rotational molding resins include fuel tanks (gasoline and diesel), hydraulic fluid tanks, chemical tanks, DEF tanks, and hot liquid tanks. These parts are made as mono-layer or multi-layer, depending on the application, if a barrier resin is required or the use of post industrial or post consumer recycled resin is used.

The rotational molding process also makes products for pressure vessel applications. For example, crosslinked polyethylene can be used to make liners for compression overwrapped pressure vessels (COPVs).

Materials used in rotomolding include polyamide (PA6, PA12 or PA11), polypropylene (PP) and polyethylene (PE). PP rotomolding resin requires a higher melt temperature and exhibits higher stiffness than PE. Crosslinked PE such as Ingenia Superlink^®, is a rotomolding resin that undergoes an irreversible chemical reaction during the rotational molding process and transitions from a thermoplastic material to a thermoset material. This gives crosslinked PE (XLPE) its excellent durability. Ingenia also offers unique rotational molding products like Rototuf^®, an advanced linear resin with excellent ESCR and superior low temperature ARM impact; as well as Rotolite^®, a single shot polyethylene foaming system.