Compared to other manufacturing technologies, plastic injection molding has many advantages, which makes it one of the most popular methods for manufacturers all over the world. This technology involves the use of plastic resins and is famous for its versatility. Choosing the right materials is very important to design and develop durable products. However, there are hundreds of kinds of plastic resins on the market, each of which has its own unique performance, advantages and disadvantages, and the process of selecting the right part injection molding material for your project can be very difficult.

But do not worry! Sino-Mold’s team of material experts will be ready to help you. With rich experience in plastic resins, we know how different characteristics affect your plastic parts during production and post-production. Let us help you complete this process to ensure the success of your project.

What are Plastic Resins?

Plastic resins are one of the byproducts obtained during the refining process of crude oil. We live in a world surrounded by plastic materials and resins. These versatile materials can be found in a wide range of products, from bottles and containers to cars and medical components, due to their many desirable properties. Plastic resins encompass a large group of materials, and each type has its unique set of characteristics that make it an ideal choice for various applications. Understanding the properties of each resin type is crucial when selecting the right one for your project.

What Are Plastic Resins Made Of ?

Plastic resins are made from raw materials known as monomers through a process called polymerization. During this process, numerous monomer molecules link together to form long-chain compounds known as polymers. The characteristics and properties of plastic resins depend on the types of monomers used and the method of polymerization.

What Sets Resin Apart from Plastic ?
Resin and plastic are both significant compounds with distinct characteristics :

Origin: Resins occur naturally in plants , while plastics are synthetic and primarily derived from petrochemicals .

Definition: Plastic represents a particular type of synthetic resin , whereas resins are amorphous substances that can exist in semi-solid or solid forms .

Stability and impurities: Plastics tend to be more stable than resins and are Generally free from impurities: Resins, on the other hand , may contain unavoidable impurities .

Hardness: Plastic exhibits a dense and rigid nature , while resin typically takes on a sticky , viscous consistency .

Environmental impact: Resin, being natural, offers a more eco-friendly alternative to plastic . Plastics degrade slowly and often contain toxic additives that contribute to environmental pollution .

10 Common Plastic Resins Used in Injection Molding

Acrylonitrile Butadiene Styrene (ABS)

ABS possesses a wide range of desirable characteristics, such as durability, toughness, and strength, making it applicable across multiple industries. It boasts high tensile strength and impact resistance. Furthermore, its lightweight nature makes it perfect for use in vehicle and other automotive components production.

Another highly appreciated aspect of ABS and injection molding materials is its malleability, allowing for easy shaping. Its excellent adhesion with other plastics and materials makes it ideal for coating metals and other surfaces.

ABS plastic’s exceptional quality makes it suitable for manufacturing computer parts, medical equipment, toys, automobiles, electronics, musical instruments, and sports equipment.

Low-Density Polyethylene (LDPE)

LDPE, a type of plastic resin, exhibits excellent moisture resistance and chemical resistance. It boasts good impact strength and remarkable flexibility. Moreover, LDPE is more cost-effective compared to many other plastic resins, making it a highly economical choice. LDPE finds applications in various plastic products, including computer parts, toys, compost bins, agricultural products, and household items. Some medical product components also incorporate this plastic resin.

One limitation of this plastic resin is its inability to withstand high temperatures, although it performs admirably in low-temperature environments.

High-Density Polyethylene (HDPE)

In the realm of food packaging, High-Density Polyethylene (HDPE) stands out among various plastic resins. This remarkable resin exhibits exceptional resistance to high impact, moisture, and heat. Its impressive tensile strength ensures durability and prevents breakage or fractures.

HDPE is the preferred choice for applications that demand strength, heat resistance, and stiffness. With its high heat resistance, it finds wide usage in the production of kitchenware, water bottles, plastic bags, and more.

Polypropylene (PP)

Polypropylene (PP) offers a plethora of advantages in production, spanning from its chemical and electrical resistance to good dimensional stability and its impressive elasticity. Moreover, its high melting point makes it particularly effective for crafting plastic components exposed to elevated temperatures.

With high stress, good chemical resistance, and excellent tensile strength, PP stands as a robust plastic choice, widely favored for insulation purposes. Many manufacturers opt to enhance its strength by incorporating fillers into the resin.

The versatility of PP extends to various sectors, including automotive, construction, and electronics. In the food and beverage industry, PP is a safe option for producing food containers and packaging. Additionally, its ability to reduce friction between objects opens doors for its application in manufacturing point-of-contact plastics.

Polyamide (Nylon)

Polyamide, commonly known as Nylon, stands as one of the most dependable plastic resins with remarkable stability. Its impressive resistance to electricity, wear and tear, and chemicals sets it apart. Due to its outstanding wear resistance, it finds its ideal applications in crafting products exposed to chemical contacts, abrasion, and high impact scenarios.

This versatile resin finds use across various fields, with significant presence in the automotive industry. Additionally, Nylon is extensively utilized in the production of sports gear and medical components. Its exceptional properties make it a reliable choice for a wide array of applications.

Polycarbonate (PC)

Polycarbonate, renowned for its exceptional hardness, stands out for its impressive impact resistance. Its high resistance to fire and heat makes it a perfect fit for environments with extreme temperatures.

The transparent nature of this resin makes it highly valuable in sectors that require see-through materials. Notably, polycarbonate finds widespread applications in the automotive industry for crafting bulletproof glass, in the mobile industry for producing phone screens, and in medical devices for optical lenses.

Moreover, this versatile plastic resin is also well-suited for manufacturing DVDs and various car parts. Its broad range of applications makes it a highly sought-after material in diverse industries.

Polyetheretherketone (PEEK)

PEEK, renowned for its exceptional resistance to chemical attack, boasts a wide range of applications. Its remarkable resistance to aqueous and heat degradation further adds to its appeal.

PEEK resin stands as one of the strongest materials, finding utility in the automotive industry for crafting compressor plates, piston parts, and pumps. Its excellent chemical resistance, also makes it an ideal choice for the chemical processing industry and its application in liquid chromatography columns.

Acrylic (PMMA)

PMMA, also known as Polymethyl methacrylate or acrylic, holds a prominent position as one of the world’s most popular resins. Similar to PC resin, acrylics offer transparency, making them a preferred choice for manufacturing see-through products. Picture frames, eye lenses, car screens, and even paints are commonly produced using this versatile acrylic resin.

Beyond its transparency, acrylic possesses other valuable attributes, such as its hardness and impact resistance. This makes it highly suitable for products that require durability and protection against impact. Furthermore, acrylic is readily available, and its cost-effectiveness makes it an attractive option for plastic production.

Thermoplastic Polyurethane (TPU)

When it comes to production requiring elasticity, TPU (Thermoplastic Polyurethane) takes the lead as the preferred plastic resin. With elasticity comparable to rubber, TPU is a soft plastic resin that can be easily molded into various products using the plastic injection molding technique.

Its impressive ability to withstand high temperatures, combined with high tensile strength, makes it a suitable choice for applications such as cable insulations, sports gear, and electrical tools. TPU’s flexibility and robustness open up a wide array of possibilities for diverse industries.

1. Polyoxymethylene (POM)

POM (Polyoxymethylene), known for its excellent colorization properties, heat distortion resistance, soft and elastic properties and low moisture absorption, finds applications in various sectors where dimensional stability is crucial. Notably, it is extensively used in the automotive industry, plastic gear production, and the food and beverage industry.

Among its key qualities are reduced friction, hardness, and resistance to chemicals, wear, and tear. Its friction-reducing ability makes it well-suited for manufacturing pumps and valve parts. Guitar picks, fixtures, and buckles, on the other hand, benefit from the hardness of this versatile plastic resin. The diverse range of applications showcases the utility and value of POM in different industries.

Which factors should be considered when choosing plastic resin?

When looking for plastic resin suitable for your production needs, thorough research is very important. In order to make informed decisions, the following are some key factors to consider when selecting plastic resins.

1. Mechanical Requirements: Plastic resins has definite characteristics and needs careful consideration before making an ideal choice. Manufacturers can use fillers, such as silica, mica, glass, clay or calcium carbonate, to change and enhance the properties of resin.

• Hardness: This is a measure of the ability of materials to resist indentation. Rockwell hardness determined by hardness testers determines the hardness of plastic resins. Different plastic products require different hardness levels, so manufacturers must choose suitable resin according to specific design requirements and environmental factors.
• Flexibility: Also known as flexural rigidity, it is a measure of the ability of plastic resin to bend without breaking. Please be aware that flexibility does not necessarily mean softness. For example, nylon is soft, but it breaks easily under pressure, while ABS is a hard plastic, which can be bent without breaking.
• Tensile Strength: this relates to the ability of materials to bear loads without breaking or cracking. Before selecting the plastic resin for production, consider the expected use of the product. Some resins have higher tensile strength than others, enabling them to bear heavier loads. Manufacturers can also enhance tensile strength using carbon fiber or glass fillers.

2. Chemical compatibility: Plastics is everywhere, and its interaction with other chemicals is inevitable. Processing agents and even cleaning agents may interact with the resin. Before selecting a plastic resin for production, verify whether the manufacturer has provided the test data on its interaction with chemicals. This consideration helps to determine how the plastic behave and react when they come into contact with these substances.

3. Environmental adaptability: different resins have different tolerance to high and low temperatures. Always look for data on the performance of plastic resin in extremely hot or cold conditions. This is especially important if the product are exposed to extreme temperatures. Another environmental factor that needs to be considered for plastic material is performance under exposure to ultraviolet (UV) radiation and humidity.

4. Weight: the density of plastics hydrocarbons determines their weight. The weight of plastic resins plays an important role in determining whether it is suitable for certain production processes. Plastic resins can be light or heavy, providing various manufacturing applications. For example, PVC is heavy, while polypropylene is light.

5. Material Cost: Various factors will affect the cost of plastic resins, including the difficulty in production, performance and availability. The richer the plastic resin is, the cheaper the price is. On the other hand, if it is challenging to produce resin, the cost will be higher. However, before considering cost, please make sure that you also evaluate the performance of other resin characteristics that meet the production requirements.

 Conclusion

In plastic injection molding, common plastic resins are crucial, offering diverse options for global manufacturers. Each resin has unique qualities, playing a key role in various applications. From ABS’s durability to LDPE’s cost-effectiveness and PC’s transparency and heat resistance, these resins provide numerous possibilities.

In addition to the above commonly used materials, there are also various special engineering materials, welcome to contact us for your products.

Choosing the right resin involves considering mechanical, chemical, environmental factors high performance engineering components, and cost. The right choice ensures top performance, quality, and sustainability, reducing costs and boosting efficiency.

Choose Sino Mold for Custom Material Selection

Save time and money while ensuring top performance and manufacture ability. With our experienced team, explore the best material options for your project.

At Sino Mold, we prioritize quality and innovation, providing reliable, high-quality custom solutions. Partner with us for successful material selection and plastic injection molding process. Achieve excellence in your products with Sino Mold.