When it comes to injection molding, selection of materials plays a critical role in determining features of the finished product. The plastics which are used by China’s injection molding industry vary as they need to be tailored to serve diverse application needs. A widely applied material is polypropylene (PP). PP is widely known as the most flexible and economical material. This has good chemical resistance, high melting point and also possesses superior impact strength. Such traits ensure that it can be used in the automotive, consumer products as well as packaging industries. However, there are some limitations of PP such as sensitivity to radiation by harmful ultraviolet rays that result in degrading on prolonged exposures to light and these materials may not withstand high temperatures. 

Besides, polystyrene (PS) is another major material used for injection molding in China. Transparent, translucent are highly clear, so that it is very useful to use this material in the product with high value transparency products like packaging of the foods and production of optical lenses. PS does not weigh much and it’s also cheap, though it fractures very easily unlike others. It is moreover susceptible to the stress cracking caused by the environment. 

ABS is a common thermoplastic that has high flexibility and great strength for use on different applications ranging from car parts to entertainment gadgets. ABS provides a perfect blend of properties such as good impact resistance, high temperature resistance and processability. It has however lesser chemical resistance compared to some other material and this can restrict its suitability in certain applications.

Polystyrene (PS):

Polystyrene which is light and easy to shape has found its way in several fields with special focus on packing and cutlery that are discarded after use. Businesses choose this material for making food containers, cups, and utensils for its efficiency and versatility at reasonable prices. It is also worth stating that Polystyrene’s brittleness is its weakness if long durability is desired. The plastic is excellent from an economic standpoint. It can be used for everyday things; however, such plastics cannot withstand high loadings and pressures and are prone to cracking when struck.

Polypropylene (PP):

Polypropylene is a work horse among plastics. It can be used in a variety of ways, such as in auto parts or consumer goods due to its adaptability and strength. Furthermore, polypropylene demonstrates excellent chemistry resistance, heat resistance, and electrical isolation, which gives it even more edge in sectors where performance is important.” However, its roughness on the surface may be problematic. Being an intrinsically oily substance may result in limited paint application and bonding, thus polypropylene must be pre-treated for proper adherence. However, it retains exceptional mechanical and chemical properties making it widely utilized.

Polyethylene (PE):

Polyethylene is celebrated for its flexibility and moisture resistance, making it a prime choice for items such as plastic bags, water pipes, and various irrigation systems. Its ability to withstand contact with liquids and water without deteriorating makes it an excellent candidate for applications where maintaining a moisture barrier is essential. However, its lack of rigidity can be a limitation when it comes to load-bearing products or structural components. While it excels in preserving the integrity of contents in a plastic bag or efficiently transporting fluids through pipes, it may not be the best choice for products requiring substantial structural support.

Polyvinyl Chloride (PVC):

Polyvinyl Chloride, commonly known as PVC, boasts impressive durability and chemical resistance, making it a go-to material for applications ranging from plumbing pipes to medical devices. Its ability to endure exposure to a wide array of chemicals and harsh environments positions it as a reliable choice for industries with stringent requirements for material performance. However, it’s important to exercise caution when processing PVC, as the material can emit potentially harmful fumes. Adequate ventilation and safety measures are necessary to mitigate any risks associated with its production and usage.

Polycarbonate (PC):

Polycarbonate stands out for its notable combination of strength and transparency, making it a preferred material for items such as eyewear lenses and electronic device components. Its exceptional impact resistance and optical clarity contribute to its popularity in these applications. Nonetheless, one of its vulnerabilities lies in its susceptibility to scratches, which can affect the visual quality of products over time. Furthermore, prolonged exposure to sunlight can lead to yellowing, affecting its aesthetics. While it excels in providing optical clarity and robustness, special care may be needed to maintain its appearance and performance in extended use scenarios.

Acrylonitrile Butadiene Styrene (ABS):

ABS has been very strong in providing different colors and has found a place of being used for household utensils as well as playthings. Manufacturers are also attracted by its resistance to impact, wide range of colors available to choose from hence creating visually appealing consumer goods. Nevertheless, it should be noted that this approach has some limitations when using it in a medical setting. However, in case of ABS, it is prone to side effects and thus cannot be applicable as a medical implant. Its suitability for the medical grade requirements could, however, be compromised by safety considerations.

Conclusion:

In China’s injection molding industry, the choice of materials is critical. Each offering comes with unique pros and cons, making it necessary to choose wisely and align with desired product characteristics. Understanding these materials can aid manufacturers in making informed decisions while maintaining a balance of performance, cost, and environmental considerations.