Plastic Materials Used In Injection Molding

Though there are many plastics for injection molding. The following are the top picks and their unique characteristics.

1. Nylon (Polyamide, PA)

Nylon comes in different grades and can conveniently replace metals for vehicle parts. However, it may be tricky to mold nylons. This is because nylon shrinks fast, so the mold may not be filled properly.

2. Polyethylene (PE)

Polyethylene is the most common plastic used in manufacturing industries. Based on density, it comes in two forms (High-density polyethylene and low-density polyethylene).

High-density polyethylene is more suitable for injection molding because the heating and cooling process does not alter its physical and chemical characteristics.

3. Acrylonitrile Butadiene Styrene (ABS)

Of all injection molding materials, ABS is the most versatile. It has three isomers serving different functions. Its low melting point makes it suitable for processing by injection molding. However, ABS molded parts degrade in contact with UV and sun rays, limiting outdoor application.

4. Polyoxymethylene (POM, Acetal)

POM is a semi-crystalline polymer used to make large precision parts. Generally, this plastic has good moldability properties. Also, its excellent dimensional stability and high tensile strength of POM molded products make it suitable for the automotive and electronics industry.

5. Polypropylene (PP)

This is the second most used plastic in injection molding applications known for its lightweight and high melting point. Though easy to mold, polypropylene is highly flammable, and it is difficult to paint the molded part.

6. Polystyrene (PS)

Polystyrene is strong, rigid, and transparent that is resistant to degradation that comes with sterilization. As a result, it is highly applicable in the dental and optical industries.

7. Acrylic (PMMA)

Acrylic is transparent and lightweight, so it is a great alternative to glass. This plastic has low mold shrinkage but can self-ignite at extreme temperatures. Because of its resistance to UV rays and moisture, one can use it for anything from solar panels to spray paints.

8. Polycarbonate (PC)

Polycarbonate is an amorphous thermoplastic with good optical clarity. It has a low and uniform shrinkage when cooling. Also, polycarbonate retains its color after molding. It is applicable in making safety goggles and automotive parts. However, it does not apply to food packaging.

9. Thermoplastic Elastomer (TPE)

TPE is a mixture of rubber and plastic. So, it exhibits properties of both. This plastic material is expensive compared to others. Furthermore, TPE can withstand extreme temperatures associated with injection molding and does not require vulcanization. As a result, you can use TPE in medical supplies like masks and breathing tubes.

10. Thermoplastic Polyurethane (TPU)

Though a type of TPE, it is popular because of its various benefits. Thermoplastic polyurethane has better elasticity and can withstand extreme temperatures. However, it is more expensive.