News & Trends
Home > News & Trends > Company Dynamic

Introduction and application of five engineering plastics

2018-5-16   

. Polyamide (PA)

Polyamide (PA), commonly known as Nylon, is a thermoplastic resin containing repeated amide groups -- [NHCO] -- in the main chain of molecules.It includes aliphatic PA, aliphatic PA and aromatic PA.Among them, there are many aliphatic PA varieties with large yield and wide application, and its naming rules are determined by the synthesis of specific carbon atoms. 

Nylon, the main varieties are nylon 6 and nylon 66, accounts for absolute dominant position, followed by nylon 11, nylon 12, nylon 610, nylon 612, as well as nylon 1010, nylon 46, nylon, nylon 9, 13, nylon varieties have nylon 6 I, special nylon MXD6 resin (barrier property), and so on, the number of varieties of modified nylon is various, such as reinforced nylon, monomer casting nylon (MC nylon), reaction injection molding (RIM) nylon, aromatic nylon, transparent nylon, high impact (super tough nylon, nylon, electricity conductive nylon, flame retardant nylon,Nylon and other polymer blends and alloys meet different special requirements, widely used as substitutes for traditional materials such as metal and wood, as various structural materials.

Nylon is the most important engineering plastics, production in the top five engineering plastics

Properties: nylon is a ductile angular translucent or opalescent crystalline resin. Nylon as engineering plastics generally has a molecular weight of 15,000-30,000.

Nylon has very high mechanical strength, softening point high, heat resistance, low friction coefficient, wear resistance, self-lubricating, shock absorption and silencing, oil resistance, weak acid resistance, alkali resistance and general solvent, good electrical insulation, self-extinguishing, non-toxic, odorless, weather resistance, poor dyeing.The disadvantages are large absorbency, which affects dimensional stability and electrical properties. Fiber reinforcement can reduce water absorption and make it work under high temperature and high humidity.Nylon has good affinity with glass fiber.

2. Polycarbonate (PC)

Introduction: polycarbonate is A thermoplastic resin containing -- [o-r-o-co] -- chain segments in the molecular hairy chain. It can be divided into fat rotation, lipocyclic and adipo-aromatic groups according to the different esters in the molecular structure. Among them, the aromatic polycarbonate with practical value is the polycarbonate, and bisphenol A polycarbonate is the most important. The molecular weight is usually 3-100,000.

Polycarbonate, or PC as it is known in English.PC is an amorphous, odorless, non-toxic and highly transparent colorless or yellowish thermoplastic engineering plastic with excellent physical and mechanical properties, especially excellent impact resistance, high tensile strength, bending strength and compression strength.Small creep and stable size;Has good heat resistance and low temperature resistance, stable mechanical properties, dimensional stability, electrical properties and flame retardant in a wide range of temperature

- 60 ~ 120 ℃ under long-term use;No apparent melting point at

220-230 ℃ in the molten state;As the molecular chain is rigid, the viscosity of resin melt is large.Low water absorption, small shrinkage, high dimensional accuracy, good dimensional stability, small film permeability;Self-extinguishing material;Stable to light, but not uv light, good weather resistance;Resistant to oil, acid, strong alkali, oxidative acid, amine and ketone, soluble in chlorinated hydrocarbons and aromatic solvents, hydrolysis and cracking are easy to be caused in water for a long time. The disadvantages are poor fatigue strength, stress cracking, poor solvent resistance and poor wear resistance.PC can injection molding, extrusion, moulding, blow molding hot molding, printing, adhesion, coating and machining, the most important processing method is injection molding.The moisture content should be less than 0.02%. The processing of trace moisture at high temperature will cause the products to produce turbidity color, silver silk and air bubbles. PC has considerable forced high-elastic deformation capacity at room temperature.High impact toughness, therefore, can be cold-pressed, cold-drawn, cold-rolled and other cold molding.The molecular weight of PC for extrusion should be more than 30,000, and the screw rod with gradual compression should be adopted. Its length-diameter ratio is 1:18-24, and its compression ratio is 1:2.5. It can be extruded and blown.

There are various kinds of PC alloys, which can improve the defects such as high viscosity of PC melt (processed type) and easy stress cracking of products. PC forms alloy or blend with different polymers to improve the properties of materials.Specific have PC/ABS alloy, PC/ASA alloy, PC/PBT alloy, PC/PET alloy, PC/PET/elastomer blend, PC, PC/MBS blend/PTFE alloy, PC/PA alloy, etc., there are two kinds of material performance advantages, and lower costs, such as PC/ABS alloy, PC main contribution to the high heat resistance, good toughness and impact strength, high strength, flame retardancy, ABS can improve the formability and table quality, reduce the density.The three major application fields of PC are glass assembly industry, automobile industry and electronics and electrical industry, followed by industrial machinery parts, optical disk, civil decoration, computer and other office equipment, medical and health care, thin film, leisure and protective equipment.The PC can be used as window glass, and the PC laminate is widely used in the protective Windows of Banks, embassies, detention centers and public places.PC board to do all kinds of signs, such as gasoline pump dial, car dashboard, warehouses and open business signs, point slide indicator, PC resin used in car camera system, the dashboard system and internal decoration, as a former chimney, with stiffener plate before and after the car, reflective frame, door frame, operating lever sheath, choke plate, PC is used as a junction box, socket, plug and sleeve conversion device, gasket, TV, telephone line support under the communications cable connectors, electrical brake chamber, the switchboard, switchboard components, relay case, PC can do low load, parts, used in home appliances motors, vacuum cleaners,Hair washers, coffee machines, toasters, power tools handle, all kinds of gear, worm wheel, shaft sleeve, guide, refrigerator shelf.PC is the ideal material for CD storage medium.PC bottle (container) is transparent, light in weight, good in shock resistance, high temperature resistance and corrosion solution washing.PC and PC alloy can do computer rack, shell and auxiliary machine, printer parts.The modified PC can be used for high-energy radiation sterilization, steaming and baking sterilization, blood sampling apparatus, blood oxygenator, surgical instruments, kidney dialyzer, etc., PC can be used for helmet and helmet, protective mask, sunglasses and sports shield.PC film is widely used in printing charts, pharmaceutical packaging, membrane commutator.

3. POM (POM) homopolymerization formaldehyde -- [CH2O}n -- copolymer formaldehyde -- [CH2O]n -- ch20-ch2-ch2]m -- (n>>m)

Introduction: polyformaldehyde, also known as polyoxymethylene, is known as polyxymethylene (POM) in English.Molecular structure and crystallization make its physical and mechanical properties very excellent, known as metal plastics.POM is optically opaque, crystalline, linear thermoplastic resin, with good comprehensive performance and coloring, high elastic modulus, high rigidity and hardness, specific strength and specific rigidity close to metal.Excellent tensile strength, bending strength, creep resistance and fatigue resistance, repeated impact resistance and excellent load-bearing resilience;Low friction coefficient, good abrasion resistance, good dimensional stability, good surface gloss, high viscoelasticity, small blow water, excellent electrical insulation, and not affected by temperature;Excellent chemical resistance, except strong acid, so there is vibration absorbency and sound attenuation;Small water absorption, good insulation resistance and not affected by humidity;Excellent chemical resistance: stable and oil resistant to other chemicals except strong acids, phenols and organic halides;Mechanical properties are less affected by temperature and have higher thermal deformation temperature.The disadvantages are poor flame retardancy, slow burning in case of fire, and small oxygen index. Even the addition of flame retardant is not satisfactory. In addition, weather resistance is not ideal.

Crystallinity of pom are high, mechanical strength, rigidity and thermal deformation temperature geometric acetal copolymer, acetal copolymer low melting point, thermal stability, chemical corrosion resistance, flow characteristics, the processability is superior to all polyformaldehyde, new developed product for high flow (rapid prototyping), impact resistance and reduce the mold deposit brand, also has the inorganic filler, strengthen the brand.

POM bibulous rate is greater than 0.2%, should advance dry before molding, POM melting temperature and decomposition temperature, poor formability, can be plastic, injection molding, extrusion, blow molding, welding, adhesive, coating, printing, plating, machining, injection molding is one of the most important processing methods, molding shrinkage ratio is big, high mold temperature empty, or annealing treatment, or join a reinforced material (such as non-alkali glass fiber).

POM has high strength, light weight and common building materials to replace non-ferrous metals such as copper, zinc, tin and lead. It is widely used in industrial machinery, automobile, electronic appliances, daily necessities, pipes and fittings, precision instruments and other departments.

POM is widely used in the manufacture of all kinds of sliding, rotation machinery parts, do all kinds of gears, levers and pulleys, sprockets, particularly suitable for bearings, hot water valve, precision metering valve, conveyor chain and rollers, flow meter, automobile, internal and external handle crank rotating machinery, such as Windows pump housings and impeller gas switch valve, electronic switch parts, solid body parts, terminal mirror mask, electric fans, heating plate, instrument button;The bearing of the recording tape;Various pipelines and agricultural spray port system as well as valve, sprinkler head, faucet, bath parts;Switch keyboard, button, tape reel;Temperature control timer;Power tools, garden parts;In addition, it can be used as surfboard, sailing boat and various kinds of sledge parts, watch miniature gear, sports equipment frame auxiliary parts and backpacks with various rings, fasteners, lighters, zippers, buckles;The heart pacemaker of the leaf of medical instrument;Artificial heart valve, top vertebra, prosthesis, etc.

Thermoplastic polyester

Introduced: thermoplastic polyester refers to gather the benzene dicarboxylic acid ester, saturated polyester thermoplastic engineering plastic, is mainly refers to polyethylene terephthalate (PET) and poly (butyl glycol terephthalate (PBT), and better heat resistance of poly cyclohexanol dimethyl brace terephthalate (PCT) and the new development of poly (propylene glycol terephthalate (PTT), etc. 

Polyethylene terephthalate, English name polyethylene terephthalate (PET), a large number of used as fiber, resin and engineering plastics can be divided into two broad categories, engineering plastics and engineering plastics, engineering plastics refers to bottle, film, sheet, resistant to bake food containers, etc.

PET is a cream - white or buff, highly crystalline polymer with a smooth, shiny surface.In relatively wide temperature range with excellent physical and mechanical properties, long-term use of up to 120 ℃ temperature, excellent electrical insulation, even under the high temperature and high frequency, its electric performance is good, but the corona resistance is poorer, creep resistance, fatigue resistance, frictional resistance, dimension stability is very good.PET has ester bond, which will be decomposed under the action of strong acid, strong base and water vapor. PET is resistant to organic solvent and weather.The disadvantages are low crystallization rate, difficult molding, high molding temperature, long production cycle and poor impact performance.In general, the processing and physical properties of the resin are improved by means of reinforcement, filling and blending, and the glass fiber is effective in enhancing the rigidity, heat resistance, drug resistance, electrical performance and weather resistance of the resin.However, it is still necessary to improve the defects of slow crystallization speed.Adding flame retardant and flame retardant dropping agent can improve the flame retardant and self-extinguishing of PET.

In order to improve PET performance, PET can form alloy with PC, elastomer, PBT, PS, ABS and PA.

PET (enhanced PET) is mainly processed by injection molding. Other methods include extrusion, blow molding, coating and welding, sealing, machining, vacuum coating and other secondary processing methods.Fully dry before forming.

The main applications include: electrical socket, connector, electric rice cooker handle, TV yoke, terminal table, breaker housing, switch, motor fan housing, instrument machinery parts, currency counting machine parts, iron, electromagnetic oven accessories;Flow control valve, carburetor cover, window controller, pedal transmission, switchboard cover in automobile industry;Gear, blade, belt wheel, pump parts of mechanical industry, and wheelchair body and wheels, lamp housing, illuminator housing, drain pipe joint, zipper, clock parts, sprayer parts.

5. Polyphenyl ether (PPO)

Polyphenylene ether is poly2, 6 - dimethyl-1, 4 - phenyl ether

(PPO for short), modified polyphenyl ether is a polyphenyl ether modified by polystyrene or other polymers, or MPPO for short.

PPO is non - toxic, transparent, low relative density, with excellent mechanical strength, stress relaxation, creep resistance, heat resistance, water resistance, steam resistance, dimensional stability.In a wide temperature and frequency range performance is good, not hydrolysis, molding shrinkage of small, self-extinguishing flame retardant, inorganic acid, alkali resistant, resistant to aromatic hydrocarbon, halogenated hydrocarbon, oil and other performance is poor, easy swelling or stress cracking, the main drawback is that the molten illiquid, processing molding difficult, most practical applications of MPPO (PPO blend or alloy), if use PS modified PPO, can greatly improve the processing performance, improve the stress cracking resistance and impact resistance, reduce cost, heat resistance and gloss slightly lower.The modified polymers include PS (HIPS), PA, PTFE, PBT, PPS and various elastomers, polysiloxane, PS modified PPO paraffin, which is the largest product and MPPO is the general engineering plastic alloy variety with the largest dosage.The larger MPPO varieties include PPO/PS, PPO/PA/ elastomer and PPO/PBT elastomer alloy.

PPO and MPPO can adopt various processing methods, such as injection molding, extrusion, blow molding, moulding, foaming and electroplating, vacuum coating, printing machine processing, etc., due to high melt viscosity and high processing temperature.

MPPO and MPPO are mainly used in electronic appliances, automobiles, household appliances, office equipment and industrial machinery, etc., to make use of MPPO heat resistance, impact resistance, dimensional stability, abrasion resistance and flaking resistance.Coating and electrical properties: used for automobile panel, radiator grid, speaker grille, console, fuse box, relay box, connector, wheel cover;Widely used in the electronics and electrical industry for connector, coil winding shaft, switch relay, tuning equipment, large electronic display, variable capacitors, battery accessories, microphone and other parts.Home appliances for TV, camera, video tape, tape recorder, air conditioner, temperature, rice cookers and other parts.Can be photocopier, computer systems, printers, fax machines and other external components and components.Also can be camera, timer, water pump, blower shell and parts, silent gear, pipe, valve body, surgical instruments, disinfector and other medical equipment parts.Large blow molding can be used to make large auto parts, such as flow baffle, bumper, low foaming forming, which is suitable for high-rigidity, dimensional stability, excellent sound absorption and complex internal structure.