Guide for Material Properties of Injection Molding Processes

Common injection materials for injection molding include ABS, PC, PE, PP, PS, PA, POM, etc. Different materials have different properties. When selecting processing materials, you can choose them according to the performance requirements of the product itself

ABS plastic

ABS plastic is a terpolymer of acrylonitrile (A), butadiene (B) and styrene (S), with light ivory color, opaque, non-toxic and tasteless. ABS is one of the most widely used engineering plastics because of its easy availability of raw materials, good comprehensive performance, low price and wide use.

Properties of ABS plastics:

1. High mechanical strength, strong impact resistance and good creep resistance;

2. It is hard, tough and rigid;

The surface of ABS plastic parts can be electroplated;

ABS can be blended with other plastics and rubber to improve its performance, such as (ABS+PC).

Typical application range:

It is generally used in the electrical enclosures of automobiles, televisions, refrigerators, washing machines, air conditioners, etc.

PC (Polycarbonate)

PC plastic is a hard material, commonly known as bulletproof glass, which is non-toxic, tasteless, odorless, transparent, flammable, but can self extinguish after leaving the fire.

Polycarbonate characteristics:

It has special toughness and hardness, and its impact strength is the best among all thermoplastic materials;

Excellent creep resistance, good dimensional stability and high molding accuracy;

Good heat resistance (120 ℃);

The disadvantages are low fatigue strength, large internal stress and easy cracking;

The abrasion resistance of plastic parts is poor.

Typical application range:

Electrical and commercial equipment (computer components, connectors, etc.), appliances (food processing machines, refrigerator drawers, etc.), transportation industry (front and rear lights of vehicles, dashboard, etc.).

PP soft glue (polypropylene)

PP soft glue, commonly known as 100 fold soft glue, is a colorless transparent or shiny granular material, which is a crystalline plastic.

The properties of polypropylene are as follows:

1、Good fluidity and good molding performance;

2、Excellent heat resistance, it can be boiled and sterilized at 100 ℃;

3、High yield strength;

4、Good electrical performance;

5、Poor fire safety;

6、Poor weather resistance, sensitive to oxygen, easy to be affected by ultraviolet light and aging.

Typical application range:

The automobile industry (mainly uses PP containing metal additives: mudguard, ventilation pipe, fan, etc.), equipment (dishwasher door liner, dryer ventilation pipe, washer frame and cover, refrigerator door liner, etc.), and daily consumer goods (lawn and garden equipment such as lawn mower and water sprayer, etc.).

PE

PE is one of the commonly used polymer materials in daily life. It is a white waxy solid, slightly horny, odorless, tasteless and non-toxic. Except for the film, other products are opaque, which is because PE has a high crystallinity.

The properties of polyethylene are as follows:

Low temperature resistance or cold resistance, corrosion resistance (no nitric acid resistance), insoluble in general solvents at room temperature;

Low water absorption, less than 0.01%, excellent electrical insulation;

With high ductility, impact strength and low friction, it shows strong creep under the action of continuous force, which can be reduced by adding short fibers.

Low water permeability but high air permeability, suitable for moisture-proof packaging;

The surface has no polarity, which is difficult to bond and print;

It is not resistant to ultraviolet rays and has poor weather resistance, and will become brittle in the sun;

Large shrinkage, easy to shrink and deform (shrinkage: 1.5~3.0%).

Typical application range:

It is widely used for manufacturing plastic bags, plastic films, wire and cable cladding and coating, etc

PS (polystyrene)

PS, commonly known as hard glue, is a colorless, transparent, shiny granular material.

The properties of polystyrene are as follows:

1、Good optical performance;

2、Excellent electrical performance;

3、Easy forming and processing;

4、Good dyeing performance;

5、The biggest disadvantage is brittleness;

Low heat resistance temperature (the maximum operating temperature is 60~80 ℃);

Poor acid resistance.

Typical application range:

Product packaging, household products (tableware, tray, etc.), electrical (transparent containers, light scattering devices, insulating films, etc.)

PA (nylon)

PA is an engineering plastic, which is made of polyamide resin, including PA6, PA66, PA610, PA1010, etc.

The characteristics of nylon are as follows:

Nylon has high crystallinity;

High mechanical strength and good toughness;

High tensile and compressive strength;

Outstanding fatigue resistance, wear resistance, corrosion resistance, heat resistance, non-toxic;

Excellent electrical performance;

Poor light resistance, easy to absorb water, not acid resistant.

Typical application range:

Because of its good mechanical strength and stiffness, it is widely used in structural components. It is also used to manufacture bearings due to its excellent wear resistance.

POM

POM, also known as Saigang, is a hard material and an engineering plastic. Polyoxymethylene has a crystal structure, has excellent mechanical properties, high elastic modulus, high rigidity and surface hardness, and is known as the “competitor of metals”.

The properties of polyoxymethylene are as follows:

Small friction coefficient, excellent wear resistance and self-lubricating property, second only to nylon, but cheaper than nylon;

Good solvent resistance, especially organic solvent, but not resistant to strong acid, alkali and oxidant;

Good dimensional stability, can manufacture precision parts;

Large molding shrinkage, poor thermal stability, easy to decompose when heated.

Typical application range:

POM has very low friction coefficient and good geometric stability, which is particularly suitable for making gears and bearings. Due to its high temperature resistance, it is also used for pipeline devices (pipeline valves, pump shells), lawn equipment, etc