Injection Molding Materials: Choosing the Right One for Your Injection Molding Manufacturing

Injection molding manufacturers who are successful in the industry can always use the well-performance injection molding material in their business. Good molding material can take not only the durable usage but the comfortable user experience.

Different molding materials have different characters because of their various components. You should consider the color, flexibility, durability, texture, and functionality of molding materials when you want to build an injection molding business.

What Kind of Molding Materials We Should Know?

Plastics are a wide range of synthetic or semi-synthetic organic compounds that are malleable and so can be molded into solid objects. As it can be easily shaped by heat temperature or curing, plastic materials are widely used in the molding industry.

Generally speaking, we use two wide range of molding materials.


Thermoplastic: also called thermosoftening plastic. It is a plastic polymer material that becomes pliable or moldable at a certain elevated temperature and solidifies upon cooling. It is widely used in plastic injection molding. The common kinds of thermoplastic are ABS, Nylon, Polyethylene, Polystyrene, etc.

Thermosetting resin: also called thermoset. It is a polymer that is irreversibly hardened by curing form a soft solid or viscous liquid prepolymer or resin. This kind of plastic materials can be used in compression molding. The common thermosetting resins including Polyester resin, Polyurethanes, Melamine resin, Epoxy resin, etc.

Thermoplastic VS. Somersetting resin

As thermoset and thermoplastic technology is progressing, both of them have a definite place in the molding area.


Differences between the two mainly exist in the structure. Thermoplastics have the form of composites which are most commonly not reinforced. It can be formed into shapes that rely solely on the short, discontinuous fibers from which they are comprised to maintain their structure. While thermoset has another structure, most commonly fiberglass and carbon fiber, for reinforcement.



  • Increased impact resistance. Most of thermoplastics product has better impact resistance than comparable thermosets.
  • Thermoplastics melt in certain heat temperature and is solidified by cooling. It can be reshaped with the same condition.


  • High-require of temperature and press. During the injection molding process, temperature and press need rigorous controlling, if not, the molding parts may have molding defects.



  • Mass production. Thermosets can be shaped by using a vacuum or positive pressure pump quickly, which allows mass production.
  • Lower cost. It can produce superior products at a low raw-material cost.


  • It cannot be reshaped. When a thermosetting resin was catalyzed, it can not be reversed or re-shaped.

Which Material Is Commonly Used in Injection Molding?

Thermoplastics! This kind of molding materials are easily melted and solidified. It just needs heat temperature to melt and cooling system to solidify. Different plastic materials have different looks, performances because of their various chemical makeup, color, or other factors.

The Commonest Thermoplastic Materials List

Polyetherimide (PEI)


Polyetherimide is well-known as its high heat resistance and excellent mechanical properties. With the properties, PEI is widely used in commercial aircraft interiors, healthcare products, cooking utensils, fiber optics, electrical products and parts. This kind of thermoplastic has exceptional strength and impact modulus, high dielectric strength, broad chemical resistance, excellent machinability and finishing characteristic, outstanding processability on conventional molding equipment, flame resistance with low smoke evolution. It is also biocompatible.

Polysulfone (PSU)


It is a high temperature, amber-colored, semi-transparent plastic material with good mechanical properties. It is available for FDA compliance, and also resistant to degradation from hot water and steam. It is widely used in medical instrument components, manifolds, medical trays, etc.

Polyphenylsulfone (PPSU)


PPSU has high toughness and heat resistance, it also has resistance to radiation sterilization as well as weak acids. It can be used as medical instrument components, sterilization trays, automotive fuses, interior aircraft parts, hot water fitting, sockets, and connectors.

Polyether Ether Ketone (PEEK)


PEEK is a high-temperature and high-performance resin. It has a heat resistance and flame retardancy, excellent strength and dimensional stability, and good chemical resistance. Therefore, it is widely used as bearing, piston parts, and pumps, cable insulation in the medical, aerospace, and automotive industries. Get more information about peek plastic injection molding services.

Polymethyl Methacrylate (PMMA)


This kind of plastic material is also called Acrylic. It is a transparent thermoplastic widely used as a lightweight, shatter-resistant alternative to glass in optical devices and products. This material can be made colored and fluorescent, and it is abrasion-resistant, bullet-resistant, UV-tolerant, non-glare, and anti-static. PMMA is 17 times more impact resistant than glass, either easier to handle and process. It also has wide applications.

Polyvinyl Chloride (PVC)


PVC is the third-most produced synthetic plastic polymer. It can be made in rigid or flexible products, and it can blend with other materials. The rigid form of PVC is commonly used in the construction industry such as doors, windows, bottles, etc. The softer and more flexible form of PVC usually blends with plasticizers such as phthalates, and it can used as materials of plumbing products, electrical cable insulation, clothing, medical tubing, etc.

Polyethylene (PE)


It is the most popular plastic injection molding material in the world. According to the study, it accounts for 34% of the plastic materials market. Polyethylene can be divided as to its density into low-density polyethylene (LDPE) and high-density polyethylene (HDPE).

LDPE is made in high pressure and high temperature environment. It is the most flexible type of polyethylene and widely used in packaging. It has superior moisture resistance, high impact strength, and good chemical resistance. It can be easily processed by most methods.

Polyethylene is used in our daily necessities such as plastic films, bottles, containers, lids and caps. Moreover, it can be used in toys and computer components production.

Polypropylene (PP)


It is the second popular plastic in the world, after polyethylene (PE). It has similar characteristics as PE, while it has more heat resistant and harder features than PE. It widely used in the packaging and labeling industries. PP has fatigue and chemical resistance, while vulnerable to UV radiation and it is flammable. It can be customized easily with additives, and naturally white.

It is also used in many common items such as buckets, packaging, bottle caps, toys, etc.

AcrylonitrilePolycarbonate (PC)


Polycarbonate is tough, stable, and transparent, thus it is very suitable for engineering. It is as clear as glass while is 215 times stronger than it. 30 times harder than Acrylic, Polycarbonate either more flexible and easier to mold, thermo-formed or cold-formed. It is used in a wide variety of products such as DVDs, sunglasses, greenhouses, sunglasses, etc.

Acrylonitrile Butadiene Styrene (ABS)


It is one of the most widely used plastic injection molding materials in the world. It has impact resistance and toughness, which make it become a popular, low-cost, commodity-level thermoplastic polymer. It also provides superior strength and temperature resistance. It has the strength and rigidity of acrylonitrile and styrene polymers and the toughness of polybutadiene, a rubbery material, even at low temperatures. This type of plastic is shiny, colorfast, high-quality surface finish.

ABS is used in a wide range of products in the automotive, appliance and electronics industries, among many others.



PC/ABS has the strength and heat resistance of polycarbonate and the flexibility of ABS. It provides improved processing, increased toughness, and dimensional stability during injection molding. It has higher heat resistance than ABS and improved low temperature impact resistance than PC. PC/ABS can be utilized in automotive, electronic, and telecommunications industries, etc.

Polyoxymethylene (POM)


This plastic material is also known as acetal, polyacetal and polyformaldehyde. It is regarded as an engineering grade thermoplastic, surpass commodity plastics in performance and price. It has high stiffness, excellent dimensional stability, and is used for precision parts requiring low friction. It also has high strength, rigidity, and hardness, and it is resistant to chemical solvent.

POM is widely used in the automotive and consumer electronics industries, and eyeglass frames, guns, knife handles, and other items which need strength and toughness.

Polystyrene (PS)


It is a common polymer which can be either solid or foamed. As a solid, it is used to make things like disposable cutlery, and in its foam state, it can be extruded to make things like disposable drinking cups.

PS has a clear surface. It is hard and fairly brittle. The natural color of it is transparent, while it can be colored with colorants. It is not biodegradable. Therefore, many PS items, contribute to the world’s litter problem.

It can be used to make CD jewel cases, license plate frames, and plastic model kits.


Generally speaking, plastic materials are widely used in the injection molding process. 5 plastic injection molding materials is commonly used in daily life. It also can be divided into Crystalline Plastics, Amorphous Plastics, and Imidized Plastics.

Choosing the right molding materials actually reduces the cost and enhance the performance of molding parts. Color, flexibility, durability, texture, and functionality are the factors you should consider when you prepare for your molding business.

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