Plastic injection molding is the core process of modern manufacturing industry, widely used in automotive, electronics, home, medical and other industries. In many plastic materials, the characteristics of different elements adapt to the needs of various scenarios. To help you choose the right material, this guide will cover 12 common plastic injection molding materials in detail, covering their performance characteristics, application advantages and applications. By comparing the parameters of these elementary substance , you will gain a better understanding of what makes each material unique, allowing you to make more precise decisions during project design and manufacturing.
PART 01：Common Plastic Injection Molding Materials
1. Polyethylene (PE)
Polyethylene is the most popular and commonly used plastic in the world. It is a lightweight, ductile, and chemically resistant material with good impact strength.
- Key Traits: Flexible, waterproof, chemical resistant
- Used For: Bags, containers, tubing, insulation, film
- Avoid When: High stiffness or heat resistance is needed
2. Polypropylene (PP)
Polypropylene is a lightweight and durable thermoplastic known for its high stiffness, heat resistance, and chemical resistance. PP can be easily recycled, making it an environmentally friendly choice for many applications.
- Key Traits: Chemical resistant, flexible, lightweight
- Used For: Food containers, household goods, auto parts, medical devices
- Avoid When: High clarity or heat resistance is needed
3. Polystyrene (PS)
Polystyrene is a versatile thermoplastic known for its clarity, rigidity, and excellent processability. PS can be easily processed through injection molding, extrusion, and thermoforming techniques.
- Key Traits: Rigid, glossy, easy to process
- Used For: Disposable cutlery, toys, appliance parts, display boards
- Avoid When: High impact strength is required
4. Acrylonitrile Butadiene Styrene (ABS)
ABS is a tough and impact-resistant thermoplastic known for its high strength, stiffness, heat resistance, and dimensional stability. It offers good chemical resistance and can be easily machined, painted, and welded.
- Key Benefit: Tough, aesthetic finish, easy to mold
- Application Used For: Appliance housings, automotive interiors, toys, electronics
- Avoid When: High temperature or chemical resistance is required
5. Polyvinyl Chloride (PVC)
PVC is a widely use on plastic injection molding materials known for its excellent chemical resistance, weather ability, and flame retardancy. PVC can be rigid or flexible, depending on the additives and processing techniques used.
- Key Traits: Durable, chemical resistant, cost-effective
- Used For: Pipes, cable insulation, medical tubes, packaging
- Avoid When: High heat or direct food contact is involved
6. Nylon (PA)
Nylon is a family of synthetic polymers used in many commercial applications. The most common types used for injection molding are Nylon 6, Nylon 6/6, Nylon 66, and Nylon 6/66, which offer improved mechanical properties, heat resistance, and chemical resistance.
- Key Traits: High strength, wear-resistant, chemical-resistant, good toughness
- Used For: Gears, bearings, automotive parts, electrical connectors, industrial components
- Avoid When: Low moisture absorption or dimensional stability in humid conditions is critical
7. Polycarbonate (PC)
Polycarbonate is a strong, durable, and transparent plastic material. It has good heat resistance and can be combined with flame retardants. However, it is susceptible to scratching and requires UV stability. PC can be easily processed through injection molding, extrusion, and thermoforming technique.
- Key Benfit: High impact resistance, transparent, heat resistant
- Application Used For: Electronics cases, lighting lenses, windows, medical parts
- Avoid When: Exposed to strong acids or bases
8. Acrylic (PMMA)
Acrylic is a strong, clear thermoplastic that allows plenty of light to pass through. It is shatter-resistant and resistant to sunlight and weather, making it suitable for applications like windows, greenhouses, and lighting.
- Key Traits: Crystal-clear, UV resistant, easy to shape
- Used For: Light covers, display panels, lenses, signage
- Avoid When: Impact or heat resistance is critical
9. Polyethylene Terephthalate (PET)
PET is a strong and lightweight thermoplastic known for its excellent barrier properties, clarity, and recyclability. PET can be easily processed through injection molding, blow molding, and thermoforming techniques.
- Key Traits: Clear, strong, food-safe
- Used For: Bottles, fibers, electrical housings, medical packaging
- Avoid When: High impact durability is needed
10. Phenol Formaldehyde Resins (PF)
Phenolic resins are synthetic polymers derived from phenol and formaldehyde, known for their excellent heat resistance, electrical insulation properties, and dimensional stability.
- Key Traits: Heat-resistant, insulating, flame retardant
- Used For: Electrical insulators, brake pads, adhesives
- Avoid When: Transparency or easy processing is needed
11. Epoxy (EP)
Epoxy resins are thermosetting polymers formed through the reaction of epoxide monomers and curing agents. It is one of the most commonly used thermoset materials for injection molding. It is a low-cost resin that can be molded in many ways and is frequently used as both an adhesive and a molding compound.
- Key Traits: Excellent adhesion, insulating, chemical-resistant
- Used For: Electronic encapsulation, composites, adhesives, coatings
- Avoid When: Flexibility is required
12. Polyurethane (PU)
Polyurethane (PU) resins are versatile thermosetting polymers known for their flexibility, toughness, and abrasion resistance. They exhibit excellent mechanical properties over a wide range of temperatures. PU resins can be formulated to have varying degrees of hardness, elasticity, and chemical resistance, making them suitable for a wide range of applications.
- Key Traits: Excellent adhesion, insulating, chemical-resistant
- Used For: Electronic encapsulation, composites, adhesives, coatings
- Avoid When: Flexibility is required
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Summary of Performance Parameters of Plastic Injection Molding Materials
| Materials | Density (g/cm³) | Tensile (MPa) | Bending Strength (MPa) | MOE (MPa) | HDT (°C) | Shrink Rate (%) | Feature |
|---|---|---|---|---|---|---|---|
| ABS | 1.05 - 1.10 | 40 - 70 | 65 - 90 | 2000-3000 | 80 - 110 | 0.4-0.8 | Good impact resistance, stable size, easy processing |
| PC | 1.20 | 60 - 70 | 90 - 100 | 2200 - 2500 | 120-140 | 0.5 - 0.7 | Good transparency, high strength, excellent heat resistance |
| PP | 0.90-0.91 | 25 - 35 | 30 - 50 | 1200 - 1500 | 100 - 120 | 1.0 - 2.5 | Good chemical resistance, light weight, fatigue resistance |
| POM | 1.41 - 1.43 | 60 - 70 | 90 - 100 | 2500 - 3000 | 100 - 120 | 1.5 - 3.5 | High rigidity, good wear resistance, dimensional stability |
| PET | 1.30 - 1.45 | 55 - 75 | 100 - 120 | 2800 - 3100 | 150 - 170 | 0.5 - 1.2 | Good rigidity, high heat resistance, good oxygen resistance |
| PVC | 1.30 - 1.58 | 40 - 55 | 70 - 90 | 2000 - 2500 | 70 - 80 | 0.2 - 0.6 | Excellent chemical resistance, good electrical insulation |
| PMMA | 1.18 - 1.20 | 50 - 75 | 75 - 110 | 2500 - 3000 | 75 - 105 | 0.2 - 0.6 | High transparency, good weather resistance, easy processing |
| PE | 0.91 - 0.96 | 10 - 30 | 20 - 40 | 400 - 800 | 40 - 80 | 1.5 - 4.0 | Good water resistance, good impact resistance, good softness |
| PS | 1.04 - 1.07 | 30 - 50 | 60 - 80 | 1800 - 2200 | 60 - 80 | 0.4 - 0.8 | Transparency, good electrical insulation, good rigidity |
| TPU | 1.05 - 1.25 | 25 - 55 | 30 - 80 | 200 - 1000 | 50 - 100 | 1.2 - 2.5 | Good elasticity, wear resistance, low temperature resistance, flexibility |
| PF | 1.25 - 1.35 | 30 - 50 | 80 - 100 | 3000 - 3500 | 150 - 180 | 0.8 - 1.0 | High heat resistance, excellent insulation, good chemical resistance |
| EP | 1.15 - 1.20 | 50 - 90 | 80 - 120 | 2500 - 3500 | 130 - 180 | 0.2 - 1.0 | Excellent adhesion, chemical and electrical insulation resistance, good heat resistance |
In the plastic injection molding process, the choice of materials is crucial, and the properties of different materials directly affect the quality, durability and production costs of the product. This guide provides a detailed analysis of the performance parameters of 12 common plastic injection molding materials, hoping to provide effective help in your material selection. Understanding the properties of different materials will help you achieve a better balance between product function and quality in future projects, driving the pace of innovation and sustainable development.
