Top 10 Common Injection Molding Plastics

Injection molding is one of the most widely used manufacturing processes, playing a crucial role in industries such as home appliances, automotive, medical, and packaging. Different plastic materials offer unique properties, and selecting the right one is essential for product performance, cost, and durability. This article introduces the top 10 common injection molding plastics, comparing their advantages, disadvantages, and applications to help you make a suitable decision.

1. ABS (Acrylonitrile Butadiene Styrene)

Pros: High strength, impact-resistant, easy to process, smooth surface suitable for plating.
Cons: Poor UV resistance, prone to aging when used outdoors.
Applications: LEGO bricks, keyboard keys, car interiors.

2. Polypropylene (PP)

Pros: Lightweight, chemical-resistant, microwave-safe (food-grade).
Cons: Brittle at low temperatures, may yellow over time.
Applications: Food containers, bottle caps, medical syringes.

3. Polyethylene (PE)

HDPE (High-Density PE): Rigid and impact-resistant, ideal for heavy-duty containers.
LDPE (Low-Density PE): Flexible, commonly used for plastic bags.
Applications: Shopping bags, water pipes, toys.

4. Polystyrene (PS)

GPPS (General Purpose PS): Transparent but brittle, used in disposable cups.
HIPS (High Impact PS): Toughened, used in refrigerator liners.
Cons: Poor resistance to organic solvents.

5. Polycarbonate (PC)

Pros: Extremely strong, transparent (glass alternative), heat-resistant (up to 120°C).
Cons: Expensive, may yellow with prolonged exposure.
Applications: Bulletproof glass, smartphone cases, safety helmets.

6. Nylon (PA)

Pros: Wear-resistant, heat-resistant (up to 150°C), self-lubricating.
Cons: Absorbs moisture, leading to dimensional changes—requires pre-drying.
Applications: Gears, sports equipment, fishing lines.

7. POM (Polyoxymethylene, Acetal)

Pros: High rigidity, low friction, ideal for precision parts.
Cons: Poor resistance to strong acids, releases formaldehyde during processing.
Applications: Zippers, clock gears, spray nozzles.

8. PET (Polyethylene Terephthalate)

Pros: Food-safe, recyclable, high clarity.
Cons: Requires thorough drying before injection molding.
Applications: Beverage bottles, packaging films.

9. TPE/TPR (Thermoplastic Elastomer/Rubber)

Pros: Soft and elastic, can be reprocessed.
Cons: Low heat resistance (<80°C).
Applications: Phone cases, fitness bands, seals.

10. PMMA (Acrylic, Polymethyl Methacrylate)

Pros: 92% light transmittance (better than glass), weather-resistant.
Cons: Scratches easily, brittle.
Applications: Advertising displays, car taillights, clear aligners.

How to Choose the Right Common Injection Molding Plastics?

Need high strength? → PC, PA

Food contact? → PP, PET

Low cost? → PE, PS

High transparency? → PMMA, PC

Need flexibility? → TPE

Each plastic has unique properties, so the choice depends on cost, durability, and processing requirements. We hope this guide helps you better understand these common injection molding plastics and assists in your product design decisions! If you have any customized mold or component needs, welcome to contact us at your free time!