Introduction to polycarbonate (PC)
Polycarbonate is a thermoplastic resin containing -[O-R-O-CO]-links in the main chain of the molecule. According to the ester contained in the molecular structure Different bases can be divided into aliphatic, alicyclic, and aliphatic-aromatic types. Among them, aromatic polycarbonate is of practical value, and bisphenol A-type polycarbonate is the most important. The molecular weight is usually 30,000-100,000. .
Polycarbonate, the English name is Polycarbonate, or PC for short. PC is an amorphous, odorless, non-toxic, highly transparent colorless or slightly yellow thermoplastic engineering plastic with excellent physical and mechanical properties, especially excellent impact resistance, high tensile strength, flexural strength, and compressive strength; Small creep, dimensional stability; good heat resistance and low temperature resistance, stable mechanical properties, dimensional stability, electrical properties and flame retardancy in a wide temperature range, can be used at -60~120℃ It has no obvious melting point and is in a molten state at 220-230℃; due to the high rigidity of the molecular chain, the resin melt viscosity is high; the water absorption rate is small, the shrinkage rate is small, the dimensional accuracy is high, the dimensional stability is good, and the film has low air permeability ; It is a self-extinguishing material; stable to light, but not resistant to ultraviolet light, and has good weather resistance; resistant to oil, acid, strong alkali, oxidizing acids, amines, and ketones; soluble in chlorinated hydrocarbons and aromatic solvents. Being in water for a long time can easily cause hydrolysis and cracking. The disadvantages are that it is prone to stress cracking due to poor fatigue resistance, poor solvent resistance, and poor wear resistance.
PC can be injection molded, extruded, molded, blow molded, thermoformed, printed, bonded, coated and machined. The most important processing method is injection molding. It must be pre-dried before molding, and the moisture content should be less than 0.02. Trace amounts of moisture will cause the product to produce white turbidity, silver wires and bubbles when processed at high temperatures. PC has considerable forced high elastic deformation ability at room temperature. It has high impact toughness, so it can be processed by cold pressing, cold drawing, cold rolling and other cold forming processes. The molecular weight of PC for extrusion should be greater than 30,000. Gradient compression type screw should be used, the length-to-diameter ratio is 1:18~24, and the compression ratio is 1:2.5. Extrusion blow molding, injection-blow, injection-pull-blow molding can be used. High quality, highly transparent bottle. There are many types of PC alloys to improve the defects of PC such as high melt viscosity (processability) and easy stress cracking of products. PC forms alloys or mixtures with different polymers to improve material properties. Specifically, there are PC/ABS alloy, PC/ASA alloy, PC/PBT alloy, PC/PET alloy, PC/PET/elastomer mixture, PC/MBS mixture, PC/PTFE alloy, PC/ PA alloys, etc., have the performance advantages of two materials and reduce costs. For example, among PC/ABS alloys, PC mainly contributes high heat resistance, good toughness and impact strength, high strength and flame retardancy, while ABS can improve Formability, apparent quality, reduced density. The three major application fields of PC are glass assembly industry, automobile industry and electronics and electrical appliance industry, followed by industrial machinery parts, optical discs, packaging, computers and other office equipment, medical and health care, films, leisure and protective equipment, etc. PC can be used as door and window glass, and PC laminates are widely used in protective windows in banks, embassies, detention centers and public places, as well as in aircraft cabin covers, lighting equipment, industrial safety baffles and bulletproof glass. PC boards can be used to make various signs, such as gasoline pump dials, car dashboards, warehouses and open-air commercial signs, dot sliding indicators. PC resin is used in car camera systems, instrument panel systems and interior decoration systems, and is used as headlight covers. Reinforced car front and rear fenders, reflective mirror frames, door frame covers, operating lever sheaths, spoilers, PCs are used as junction boxes, sockets, plugs and bushings, gaskets, TV conversion devices, and communication under telephone line brackets Cable connectors, switch boxes, telephone switchboards, switchboard components, relay casings, PC can be used as low-load parts, used in household appliance motors, vacuum cleaners, shampooers, coffee machines, toasters, power tool handles, etc. Gears, worm gears, bushings, guides, refrigerator shelves. PC is an ideal material for optical disc storage media. PC bottles (containers) are transparent, light in weight, good in impact resistance, and resistant to certain high temperatures and washing with corrosive solutions. They are recyclable bottles (containers).
PC and PC alloy can be used as computer frames, casings and auxiliary machines, and printer parts. Modified PC is resistant to high-energy radiation sterilization, steaming and baking sterilization, and can be used for blood collection specimen equipment, blood oxygenators, surgical instruments, kidney dialyzers, etc. PC can be used as helmets and hard hats, protective masks, sunglasses and sports protection. Blindfold. PC film is widely used in printing charts, medical packaging, and membrane commutators.