polystyrene
DATE：2022/7/28 10:19:14 / READ： / SOURCE：This station
polystyrene
Polystyrene (PS) resin is the largest variety in the styrene series. It is made from benzene and ethylene by bulk polymerization or suspension polymerization. (1) Performance characteristics polystyrene resin is a colorless, transparent, tasteless, odorless and glossy granular solid. Its products are very similar to glass, hard and brittle; There is a crisp metal sound and easy to crack when knocking; The melting temperature is 150~180 ℃, the thermal deformation temperature is 70~100 ℃, the long-term use temperature is 60~80 ℃, and the thermal decomposition temperature is 300 ℃; It is easy to burn. When burning, it emits black smoke and a special odor; The product has high rigidity and surface hardness, low water absorption, and should be able to maintain its mechanical properties and dimensional stability in a humid environment; Light property is second only to acrylic resin; Excellent electrical properties, high volume resistivity and surface resistivity; Good radiation resistance; It has good processability and colorability, and the price is relatively cheap; Soluble in aromatic hydrocarbons, chlorinated hydrocarbons, aliphatic ketones and esters, it can resist the action of some mineral oil organic acids, bases, salts, lower alcohols and aqueous solutions. The disadvantages are: the product is brittle and easy to crack, low impact strength, poor wear resistance, flammable, and not resistant to boiling water. In order to improve the shortcomings of polystyrene resin, high-performance resins and plastics with styrene as monomer were developed through copolymerization, blending, compounding and filling. Such as high impact polystyrene (his), ethylene propylene copolymer (SAN), Methyl Methacrylate Butadiene Styrene Copolymer (MBS), acrylonitrile butadiene styrene copolymer (ABS), etc., which improves the impact strength, heat resistance, weather resistance and stress cracking resistance of polystyrene resin. (2) Molding method and application polystyrene melt has good fluidity, good molding processing performance, easy coloring and good dimensional stability. It can be molded by injection molding, extrusion, blow molding, foaming, thermoforming, welding, bonding, coating and machining. It is used for instruments, electrical appliances, televisions, toys, daily necessities, household appliances, stationery, packaging and foam cushioning materials.2.5.1 expanded polystyrene
Expanded polystyrene is also called polystyrene bead foaming material or expandable polystyrene (EPS). This kind of expanded polystyrene is mainly prepared by filling a certain amount of foaming agent (low boiling hydrocarbon) into the bead resin obtained by suspension method. (1) Performance characteristics: foamed polystyrene is white or colorless transparent beads, with a relative density of 1.05~1.06; It can be colored at will and has good chemical resistance. When heated to 90~110 ℃, the volume of expandable polystyrene containing low boiling hydrocarbon foaming agent can be increased by 5~50 times, and it becomes a kind of foamed plastic with heat insulation, sound insulation, shock resistance, water resistance, acid resistance, alkali resistance and other properties. This kind of foamed plastic is light in weight, low in thermal conductivity, low in water absorption, good in sound insulation, and has certain mechanical strength and impact resistance. It has good low temperature resistance (up to -100 ℃), and the maximum service temperature is about 70 ℃. Easy to burn, not resistant to petroleum solvents, not suitable for contact with benzene, esters, ketones. (3) Molding method and application grade polystyrene molding processing mainly adopts pressing method. Foaming products are used for shockproof, insulation, heat insulation, sound insulation and floating materials.
2.5.2 acrylonitrile butadiene styrene copolymerAcrylonitrile butadiene styrene copolymer is used to be absAbs resin in plastic processing enterprises. It is a kind of light yellow granular or bead resin. Its products are tough, hard, rigid, non-toxic, tasteless, low water absorption and excellent low-temperature impact resistance; Good dimensional stability, electrical properties, wear resistance, chemical resistance, dyeability, shape processing and machinability; The melting temperature of the resin is 217~237 ℃, and the decomposition temperature is more than 250 ℃; The resin is resistant to water, inorganic salts, alkalis and acids, insoluble in some alcohols and hydrocarbon solvents, but easily soluble in aldehydes, ketones, esters and some chlorinated hydrocarbons; The thermal deformation temperature is low, opaque, combustible and poor weather resistance. (1) Molding method ABS resin has good molding and processing properties, which can be molded by injection molding, extrusion, calendering, blow molding, vacuum and foaming. The resin has low moisture absorption, and generally the raw materials do not need to be dried. Injection molding: the melt temperature is 200~240 ℃, the injection pressure is 50~100mpa, and the molding mold temperature is 40~80 ℃. At the time of extrusion molding, the barrel temperature is 176180 ℃, 180~220 ℃ and 180~220 ℃ respectively from the feed inlet to the die end, and 180~210 ℃ at the die; The diameter ratio of screw cup is 20:1, and the compression ratio is 2.5~3. Products can be welded, bonded, and machined.(2) BS has the advantages of good integration, low lattice and easy molding, so it has become a plastic variety with large application at present. It is widely used in electronic appliances, household appliances, office equipment, instruments and meters, machinery and auto industrial equipment accessories. Such as the shells and some parts of TV sets, tape recorders, washing machines, refrigerators, telephone computers, vacuum cleaners, electric fans and air conditioners; In the instrument and light textile industry, it is used to make instrument panel and instrument box; Spindles, cameras, watches, musical instruments, etc; In the construction industry, it is used for drainage, exhaust pipes, pipe fittings, door and window frames Shutters and safety helmets, etc; In the automotive industry, it is used for some assemblies inside and outside the vehicle, heat dissipation grille, lampshade, instrument panel and control panel, etc.
2.5.3 high impact polystyrene
High impact polystyrene (HIPS) is a kind of opaque bead or granular resin, and its products have high toughness and impact resistance; The color, chemical, electrical and processability are the same as those of polystyrene, but its tensile strength, hardness, light transmittance, light resistance and thermal stability are slightly lower than those of polystyrene. With the addition of rubber, the impact strength of hips is improved. Based on the amount of rubber and the difference of resin energy, hips can be divided into three grades of toughened polystyrene: medium impact grade, high impact grade and ultra-high impact grade. 25.4 styrene acrylonitrile copolymer styrene acrylonitrile copolymer is also called San or as resin. It is a colorless or yellowish transparent granular thermoplastic resin. The impact strength is higher than that of polystyrene, with good heat resistance, weather resistance, oil resistance, seismic resistance, chemical stability and dimensional stability: the mechanical strength is better than that of polystyrene, and the transparency is the same as that of polystyrene; It can resist the corrosion of non-polar substances such as gasoline, kerosene and aromatic hydrocarbons, and is resistant to water, acid, alkali, detergent and halogenated hydrocarbon solvents. It is soluble in ketones. San resin can be molded by injection, extrusion and foaming methods. Before molding, the resin should be dried at a temperature of about 80 ℃. The temperature of the injection melt is 160~200 ℃ and the injection pressure is about 100MPa. The resin can also be molded and laminated. The products can be processed by machining, bonding, welding and surface electroplating. San products are the same as polystyrene products, and can be used to produce oil resistant mechanical parts, oil tanks, lamps, instrument panels, instrument lenses, auto parts, cultural and educational supplies, fan blades, power tools, impellers and camera parts. 2.5.5 acrylonitrile styrene acrylate copolymer (ASA resin) ASA resin is a ternary graft copolymer prepared by grafting acrylonitrile and styrene onto acrylate rubber. Compared with ABS, its weather resistance is increased by nearly 10 times, and the impact strength decreases slightly; Good processability; Good thermal stability, no deformation under high temperature environment, constant strength, generally can be used in the temperature range of -20~70 ℃; It has high insulation performance, good drug resistance, alkali resistance, animal oil and vegetable oil resistance, and good antistatic and coloring properties. ASA resin can be molded by injection, extrusion, calendering, blow molding and other processing methods, as well as secondary processing by bonding, welding, chemical plating and other methods. Because ASA resin has good weather resistance and oxidation resistance, it is not only suitable for outdoor materials, but also can be used as a representative device under indoor strong light irradiation. Such as automobile, motorcycle, agricultural machinery parts, instruments, computer shells, road signs and labor protection, sports equipment and building materials supplies.
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