Many industries take advantage of the injection molding technique to create useful plastic products because of its versatility and compatibility with many injection molding resins. It is famous for its vast advantages and wide range of applications.
There are several types of plastic molding material with varying properties and applications. However, it is essential to consider these materials and their properties when producing injection-molded plastics with specific features.
This article explores some of the top injection molding plastics, their advantages, and factors to consider in plastic selection for injection molding. Let’s get to it!
Top 10 Plastic Materials
Injection molding is an effective manufacturing process with high compatibility with various plastic materials for making products for several industries. Here are the ten top plastic materials for injection molding:
- Acrylic (PMMA)
- Acrylonitrile Butadiene Styrene (ABS)
- Nylon (polyamide, PA)
- Polycarbonate (PC)
- Polyethylene (PE)
- Polyoxymethylene (POM)
- Polypropylene (PP)
- Polystyrene (PS)
- Thermoplastic Elastomer (TPE)
- Thermoplastic Polyurethane (TPU)
The section below discusses each plastic’s material properties, advantages, and applications. However, you should note that these plastic materials are not the only ones Kemal can mold for you. There are other polymer blends and specialty plastics we can mold.
1. Acrylic (PMMA)
Acrylic or Polymethyl methacrylate is a commonly used thermoplastic material. Manufacturers often use acrylic for various see-through components because it is transparent. Acrylic is quite durable due to its shatter-resistant feature.
Acrylic has excellent impact strength and rigidity, allowing it to withstand impact without deforming. It is cost-efficient and readily available.
Acrylic offers superior quality final products due to its dimensional stability. More importantly, you can easily modify and finish acrylic parts after injection molding.
Advantages
Acrylic has excellent tensile strength with resistance to weather and scratch, making it a perfect substitute for glass.
- Low costs of production.
- Ease of machinability
- Perfect for lightweight components
- It is safer than glass
- Durable injection molded plastics
Application
Acrylic is a versatile material with applications in several industries due to its high tensile strength. Here are some of its typical applications:
- Transparent components – lighting equipment, eye lenses, view screens, etc.
- Protective casing for Solar panels
- Windows
- Picture frames
- Acrylic nails
- Automotive parts – car screens
2. Acrylonitrile Butadiene Styrene (ABS)
ABS is a common engineering-grade thermoplastic material that product designers often use in molding various components. It has a considerably low melting point, allowing it to be molded easily.
Additionally, it has an opaque appearance that enables the use of colorants and various surface finishes to enhance its appearance.
ABS contains butadiene which is responsible for its excellent strength even at lower temperatures. On the other hand, its styrene composition is responsible for the shiny, attractive finish of injection-molded ABS parts.
Although the ABS has outstanding strength and resistance to impact, it has low resistance to weather, water, and sunlight (UV).
Advantages
- ABS materials offer manufacturers significant benefits such as:
- High impact resistance, which prevents it from breaking easily
- Injection molded plastics with higher thermal resistance
- Suited for lightweight applications
Application
Typical applications of the ABS include:
- Medical devices
- Musical instruments
- Exterior and interior automobile trim
- Motorcycle helmet
- Housing equipment
- Enclosure for electronic and electronic assembles
3. Nylon (Polyamide, PA)
Nylon is another commonly used stable plastic material in injection molding. It is widely used in various industries due to its high toughness and resistance to chemicals, wear and tear, and electricity.
Consequently, it is suitable for creating products exposed to high impacts, abrasion, and chemical contact.
Polyamide is a natural compound manufactured synthetically using petroleum. This silk-like thermoplastic is suitable for diverse injection molding applications.
In addition, nylon/polyamide has vibration-damping properties/ making it the perfect material for making voice dampeners. The standard nylon used for injection molding includes Nylon 6/66, Nylon 6/6, Nylon6, and Nylon 66.
Advantages
These are some benefits of using Nylon:
- It is a cost-efficient material suited for lightweight components
- Its low friction prevents it from heating up under higher friction
- It can be combined with several other plastic materials
- Its properties make it a perfect resin for elastic and clothing applications
Application
Application of nylon includes:
- Automotive components
- Guitar strings
- Ropes
- Sports gear
- Medical parts
4. Polycarbonate (PC)
Polycarbonate is one of the strongest plastic for injection molding. It is usually hard and can withstand significant pressure/impact without deforming or developing stress fractures.
As a result, polycarbonate is a go-to choice for manufacturers of optical discs and several other plastic products.
Manufacturers and product developers often prefer this material to others due to its transparency and impact resistance.
Although polycarbonate has high impact strength and toughness, it is lightweight, which makes it a perfect material choice for original equipment manufacturers (OEMs).
Advantages
Some of the advantages of polycarbonate include the following:
- Polycarbonate is a high-quality plastic with outstanding benefits such as:
- Decent protection against discoloring or corrosion
- Its transparency makes it an ideal material for several applications
- Perfect for making electric insulation
- High impact resistance and rigidity that prevents it from dents and scratches
- Great operating temperature range (-20 degree Celsius to 140 degree Celsius)
Application
The typical applications of polycarbonate include:
- Eyewear
- Pipes for LED lights
- Sports gear
- Clear windows
5. Polyethylene (PE)
Polyethylene is another lightweight plastic resin for injection molding. It has high elasticity, chemical resistance, and electrical insulating characteristics.
Although it is not extraordinarily strong, it is pretty cost-effective. Polyethylene is popularly used in making several components due to its non-toxic nature.
Polyethylene is of three major categories with varying densities. Polyethylene Terephthalate (PET), Low-Density Polyethylene (LDPE), and High-Density Polyethylene (HDPE).
Generally, HDPE is a strong and more rigid material. In contrast, LDPE is more flexible, making it an excellent choice for packaging material and front-runner products (films, shopping bags, foil) in the packaging industry.
Advantages
- Perfect material for lightweight products
- Excellent impact strength and creep resistance
- Inexpensive
- Highly flexible
Application
Polyethylene has a wide range of applications in various plastic components, including
- Toys
- Computer parts
- Plastic bags
- Household goods
- Consumer plastic parts
- Medicine and detergent bottles
6. Polyoxymethylene (POM)
Polyoxymethylene or acetal is a semi-crystal rigid plastic material with a naturally glossy surface. POM is a go-to option for molding products that require high precision.
Consequently, product designers often use this plastic to create mechanical and automotive products, usually made with metal.
It has good lubricity and a low coefficient of friction, making it a perfect material for contact-intensive applications like pumps and valve arts.
Additionally, it has excellent dimensional stability suited for various applications due to its rigidity and stiffness.
Despite polyoxymethylene’s high resistance to solvents like detergents, motor oil, and alcohol, it is not ideal to expose it to hydrochloric acid and nitric acid.
Advantages
This injection molding material offers manufacturers a wide range of advantages in molding, including:
- Good resistance to heat and chemical and decent wear and tear properties
- High impact resistance
- High resistance to inorganic and organic acids and solvents
- Offers smooth, glossy, and reflective surface
- Good coloring properties
Application
The typical applications of polyoxymethylene include:
- Door and knife handles
- Automotive components
- Insulin pens
- Electronics – electrical devices
- Lock systems
- Household appliances – fan blades
7. Polypropylene (PP)
Polypropylene is similar to acetal, a plastic with a glossy surface. It is commonly used in various industries because of its food-safe properties, especially in commercial food applications. Likewise, it is suitable for making toys due to its affordability.
PP’s higher thermal expansion coefficient makes it ideal for high-temperature applications. Polypropylene is a perfect material for food packaging because it prevents chemicals from mixing with food products.
Additionally, PP is a solid plastic material suitable for making insulation. However, most product designers/engineers add fillers to this plastic to achieve greater strength.
Advantages
Polypropylene is an ideal molding material with vast benefits for several industries, including:
- Excellent chemical resistance and high elasticity properties
- Ability to retain its shape following a series of bending and flexing due to its high-stress resistance
- High resistance to chemicals (although it doesn’t react with most acids and bases)
- High recyclability
- High thermal expansion coefficient
Application
The typical applications of polypropylene include:
- Plastic kitchenware, storage containers, and dishwasher-safe plates
- Automotive components
- Toys
- Home appliances
8. Polystyrene (PS)
Due to its low cost, this is one of the most common types of molding material in consumer goods and packaging applications. Polystyrene is of two types when it comes to injection molding.
High Impact Polystyrene (HIPS) and General Purpose Polystyrene (GPPS). The HIPS is opaque, while the GPPS is transparent.
Product designers employ polystyrene in making hard cases for toolboxes and bodies of power tools because of its high-impact properties.
In addition, PS is a tough and durable molding material capable of withstanding all sorts of harsh conditions.
Advantages
Here are some of the benefits of polystyrene:
- Great electrical properties
- Easily molded and processed
- Transparent
- Cost-effective
- Safe for packing food items
Application
Manufacturers in various industries use this injection molding material for the following:
- Disposable bottles and food containers
- Sheeting for laminate floors
- Rigid foam insulation
9. Thermoplastic Elastomer (TPE)
Thermoplastic Elastomer is another special plastic resin for injection molding with a plastic rubber blend. It is one of the most flexible injection molded plastics.
It is highly recyclable, strong, and can be stretched to long lengths. More importantly, TPE is commonly used because of its considerably lower cost than other rubber alternatives.
However, it would help to note that even though TPE can be stretched to long strength, you should be careful not to overstretch the material as it is likely to creep. Likewise, TPE loses specific material properties when exposed to high temperatures.
Advantages
These are some of the benefits of using TPE:
- It is not expensive
- Eco-friendly
- Responds well to dye and color
- Flexible injection molded plastic
Application
TPE has a wide range of applications, including:
- Bumpers
- Flexible tubes
- Anti-vibration mounts
- Footwear components
10. Thermoplastic Polyurethane (TPU)
TPU is soft and elastic suitable for products that require elasticity. This molding plastic has elasticity properties similar to that of rubber.
Thermoplastic polyurethane possesses excellent tear and tensile strength. As a result, product designers often use it in molding parts that require elasticity.
Likewise, TPU is ideal for creating heavy-duty products that can withstand unfavorable environments and factors.
The material is soft and easy to mold into various products using plastic injection molding. Thermoplastic polyurethane resin has excellent abrasion resistance, saltwater resistance, chemical resistance, and compression strength which isn’t compromised at high-temperature levels.
Advantages
Even though TPU costs more than other plastic materials, it offers a wide range of benefits, including:
- Improves grip for hand-held products
- High ability to withstand extreme-thermal levels
- High tensile strength and flexibility
- High impact-resistance properties
Application
Here are some of the applications of the TPU resin:
- Sport gears
- Protective enclosures and casings
- Electrical tools
- Inflatable rafts
- Footwear
- Caster wheels
Factors to Consider in Plastic Material Selection for Injection Molding
Research is essential when sourcing suitable plastic materials for injection molding. For more efficient decision-making, here is an injection molding material selection guide for selecting the suitable plastic resin:
Chemical Compatibility
Plastic materials for injection molding have a wide range of applications.
Consequently, their interaction with other chemicals is inevitable. Chemicals such as process reagents and cleaning solutions can interact with plastic materials.
Therefore, before you select any plastic material for your project, it would help to check for testing data from the producers concerning its interactions with chemicals. This consideration helps to discover how plastic reacts and performs with chemicals.
Mechanical Requirements
In the process of selecting plastic materials for injection molding, always note that these plastics are defined by their injection molding material properties.
Hence, paying attention to these properties helps to guide your choice of plastic resin. More importantly, note that manufacturers can adjust and enhance the properties of plastic resin using fillers like calcium carbonate, mica, clay, glass, and silica.
Here are the mechanical requirements of plastic resins you need to examine:
- Flexibility
This is also known as the bending stiffness of a material. It helps to evaluate the plastic materials’ ability to bend without deforming.
However, it would help to note that the flexibility of a plastic resin is not the same as softness. For example, ABS is a hard resin that bends without deforming/breaking, while nylon is soft but breaks under stress.
- Tensile Strength
This has to do with the material’s ability to withstand a heavy load without fracturing or breaking. It is, however, important to continually examine the use of molded products before selecting a plastic material for its production.
Some plastic materials have higher tensile strength than others, which allows them to carry a heavier load. However, manufacturers can use glass or carbon fibers to enhance tensile strength.
- Hardness
The hardness of a plastic molding material relates to its resistance to indentation. Generally, shore hardness decides the stiffness of a plastic material, and it can be measured with a Durometer scale.
However, you should choose the perfect plastic resin for a particular design because different plastic injection molded plastic products require varying hardness levels.
Weight
The thickness of the plastic hydrocarbon decides its weight. The weight of a plastic resin influences its suitability for most production processes.
There are heavy and lightweight plastic materials for injection molding with varying manufacturing applications. For example, Polypropylene is lightweight, while PVC is heavy.
Environmental Capability
Different injection molding resins have varying tolerance levels to cold and heat. It would help to source data on how a specific plastic resin reacts when exposed to extreme cold or hot temperatures.
This is very important if product usage involves exposure to extreme temperatures. Nevertheless, the performance of products on exposure to humidity and ultraviolet light is another environmental factor to consider.
Material Cost
Several factors, such as availability, properties, and ease of production, determine the cost of plastic resins. A plastic resin is cheaper if it is readily available.
Meanwhile, such plastic may become expensive if it is complex to produce. However, always examine other resin features for production before considering the cost.
Kemal: Plastic Injection Molding Services
There are several manufacturing applications with about a dozen different types of the plastic molding material. Choosing the suitable plastic resin is a primary step in budget planning, ensuring product quality and long-term success.
At Kemal, we offer reliable plastic injection molding services. We leverage skilled experts with an in-depth understanding of making injection-molded plastics and years of experience to provide the best results. We have a wide range of materials suited for your projects and prototypes.
Likewise, we provide instant quoting and DFM analysis. We offer budget-friendly prices for your plastic injection molding services, ensuring cost optimization. Reach out to us; let us handle your project.
Conclusion
Choosing the suitable plastic material for injection molding is vital in ensuring optimal product manufacturability and performance.
You must consider your project requirements when sourcing the appropriate material. Understanding the different injection molding material properties helps to choose the right one.
