Plastic is a polymer characterized by its lightweight, durability, and high plasticity.
1- Polyvinyl chloride (PVC): PVC is a semi-crystalline thermoplastic. It appears as a white powder, non-toxic and odorless, with excellent rigidity, flexibility, insulation properties, and corrosion resistance (resistant to acids and alkalis). However, its heat resistance is poor, and decomposition releases hydrogen chloride, which exhibits certain toxicity; therefore, stabilizers must be added during molding and processing.
PVC must be processed with plasticizers during application; therefore, it is classified into two main types—hard and soft—based on the amount of plasticizer added. Hard PVC exhibits high strength and durability, making it suitable for manufacturing instruments, sports equipment, panels, pipes, motor casing components, toy shells, and other products such as bank cards, membership cards, and pipelines. Soft PVC is used in hoses, wire and cable insulation, synthetic leather, and shoe heels.
PVC molding processes include extrusion, injection molding, blow molding, and calendering.
2- Polystyrene plastic (PS): PS is a colorless, transparent thermoplastic with no odor, lightweight, high surface hardness, and excellent light transmittance (up to 90%), second only to ordinary glass and acrylic. It exhibits good corrosion resistance and low moisture absorption. With excellent processability, it can be molded using injection molding, extrusion, blow molding, or compression molding. It also possesses superior electrical insulation properties.
The drawbacks include brittleness and susceptibility to cracking, as well as poor impact resistance and heat resistance, which require modification for improvement.
General-purpose PS is widely used in instrument casings, automotive lamp covers, daily-use utensils, high-frequency insulation products, and packaging materials.
3-Phenolic plastic (PF): Commonly known as bakelite, PF is a hard and brittle thermosetting plastic. It exhibits high strength, excellent rigidity, wear resistance, and dimensional stability, along with superior insulation and heat resistance properties. Suitable manufacturing processes include injection molding and compression molding. It is widely used in the production of switches, vacuum tube sockets, and similar products.
The addition of asbestos and mica to phenolic resin enhances its resistance to acids, alkalis, and corrosion, making it suitable for use as material in chemical equipment and motors.
With advancements in technology, electret materials can now be used to manufacture stamping dies for sheet metal, making them suitable for small-batch production of sheet metal stamping components.
4-Polyamide plastic (PA): PA, commonly known as nylon, is also referred to as polyamide fiber, Nylon, or nylon fiber. It appears as a white or light yellow translucent solid. Non-toxic and odorless, it is easily colorable and exhibits excellent mechanical strength, tensile resistance, impact resistance, and good electrical insulation properties. It demonstrates superior wear resistance and lubricity, but its high water absorption can adversely affect product performance and dimensional stability.
Applicable manufacturing processes include injection molding, casting, and 3D printing.
It is commonly used in the manufacture of mechanical and electrical components such as gears, blades, bearings, and sealing rings. It is also employed in the production of packaging tapes, woven tapes, and food films. Common applications in daily life include nylon knitted fabrics and nylon textiles.
5-ABS Plastic: It is a composite material composed of acrylonitrile, butadiene, and styrene, exhibiting a translucent milky white color. It possesses excellent properties such as tensile strength, impact resistance, flowability, and surface hardness, along with superior rigidity, heat resistance, low-temperature performance, and electrical properties. ABS can be processed through methods including injection molding, extrusion, and thermoforming.
ABS plastic is widely used to manufacture various plastic casings, including those for household appliances, toys, printers, power tools, automotive components, and kitchen utensils.
6-Polypropylene (PP): PP appears as a white waxy solid, non-toxic, odorless, transparent, and lightweight. It is a low-cost everyday-use plastic and also the plastic with the lowest density. Its properties are well-balanced, featuring excellent electrical conductivity, heat resistance, rigidity, toughness, chemical resistance, and high bending fatigue strength. The drawbacks include high shrinkage rate, poor wear resistance, and susceptibility to low-temperature embrittlement.
Commonly used in pipe casings of instruments and equipment, door panels and seat frames, medical devices, luggage, toys, packaging materials, and household appliances.
7- Polyethylene plastic (PE): Polyethylene is non-toxic and odorless, appearing as milky white waxy particles with a wax-like texture and excellent low-temperature resistance. Depending on its polymerization method, molecular weight, and chain structure, it can be classified into high-density polyethylene (HDPE), low-density polyethylene (LDPE), linear low-density polyethylene (LLDPE), and ultra-high molecular weight polyethylene (UHMWPE).
HDPE: This material is hard, tough, and elastic, and can be molded using processes such as injection molding, blow molding, and extrusion. It is widely used in daily life for various applications, including plastic bottles, food packaging films, packaging calendered tapes and tying straps, ropes and cables, fishing nets, woven fibers, as well as electrical wires and cables.
LDPE: Resistant to corrosion by most acids and alkalis, with low water absorption, maintaining flexibility even at low temperatures, and exhibiting high electrical insulation properties. It is suitable for various thermoplastic molding processes. In daily applications, its primary uses are film products such as agricultural films, industrial packaging films, and pharmaceutical and food packaging films.
LLDPE: Compared to LDPE, LLDPE exhibits superior electrical insulation properties, higher heat resistance, and impact resistance. It is suitable for manufacturing films, daily-use products, pipes, wires, and cables.
UHMWPE: Primarily used in high-end applications such as plastic modification, tubing, high-strength plates, and fibers.
8-Polycarbonate (PC): PC is an amorphous thermoplastic. It appears colorless or light yellow transparent, non-toxic and odorless, with excellent mechanical properties. Its impact resistance and creep resistance are particularly outstanding. PC exhibits good heat and cold resistance, excellent electrical properties, dimensional stability, high light transmittance, and ease of molding and processing. It is suitable for manufacturing products requiring high precision and complex geometries.
It is commonly used in structural materials for medical devices, tool housings, telephones, televisions, ship components, lamp shades, optical lenses, casings for small household appliances, and the production of PC film panels, among other applications.