How to choose rotomolding raw materials

How to choose rotomolding raw materials

Common roto-molding materials on the market include: polyethylene (PE), polypropylene (PP), nylon (PA), polyvinyl chloride (PVC), polycarbonate (PC), etc.

Roto-molding requires specially designed materials. The most basic requirements include:

1. Easy to grind (or easy to keep liquid), using high-performance room temperature grinders and low temperature grinders.

2. Appropriate fluidity. Taking the most commonly used polyethylene raw material as an example, the melt index (MI, or MFI) range of the brand should generally be between 2 and 10 (g/10 minutes), and the optimized melt index range is 3-6 (g/10 minutes). If the melt index is too low, the product is difficult to mold; if the melt index is too high, the physical properties of the product will decrease.

Among the raw materials used for roto-molding, polyethylene accounts for more than 90%, and linear low-density polyethylene accounts for more than 80%.

Polyethylene powder: 

Polyethylene powder microstructure:

• First, polyethylene has a wide processing window and is suitable for long-term high-temperature environments, which also reduces the requirements for rotational molding machinery;
• Second, at room temperature, polyethylene does not react with water, most oils, acids and alkaline substances, and has a wide range of applications;
• Third, polyethylene raw materials are low-cost and easy to promote.