Flame retardant, conductive, electromagnetic shielding and magnetic polypropylene
DATE：2023/1/4 8:59:10 / READ： / SOURCE：This station
The preparation method of flame-retardant polypropylene is relatively simple: the polypropylene powder is mixed with a certain proportion of antioxidant, treatment agent, flame retardant and auxiliary flame retardant, and then it is mixed evenly and then mixed, plasticized, extruded and granulated by the extruder, which is the flame-retardant polypropylene product.
The performance of flame retardant polypropylene is related to the type of flame retardant, the amount of material used and the composition of the material in the formula. Flame retardant polypropylene has excellent flame resistance, reaching UL94 V-0 grade; It has good thermal aging property and can be used at 150 ℃ for more than 700h; The processability is similar to that of polypropylene resin, the melt fluidity is good, and large thin-walled products can be formed; The mechanical strength is close to that of polypropylene products.
See Table 2-60~Table 2-62 for the performance parameters of flame retardant polypropylene of Sinopec Beijing Chemical Research Institute, China Blue Chenguang Chemical Research Institute and Shandong Dawn Chemical Co., Ltd.
Flame retardant polypropylene can be molded into plastic products by injection molding, extrusion and hollow molding. The injection molded products, such as picture tube socket cover, line output transformer, high voltage package, coil bone frame, base, safety cover, wiring connector, etc., can be used in TV sets by making use of good high-frequency insulation of flame retardant polypropylene, electrical performance that is less affected by temperature and humidity, and high level flame retardant performance (flame resistance is V-0); Materials and equipment parts with good flame retardancy are required in the transportation, construction and textile industries, such as automobile parts, materials for railway vehicles, building materials, ships and military facilities; Flame retardant polypropylene can also be used as pipes for coal mines and oil fields, carpets and furniture for daily use.
Conductive polypropylene is mixed with 55%~85% polypropylene powder, 10%~40% conductive carbon black (V-Z type) and an appropriate amount of CF antioxidant, lubricant, plasticizer and other auxiliary materials. After being mixed evenly in the mixer, it is put into the open mill for mixing. After being plasticized and mixed evenly, it is pulled into sheets and coiled. Then, it is pelletized with a pelletizer to make conductive polypropylene granules.
Conductive polypropylene has good processability and mechanical properties, as well as good conductivity and electromagnetic shielding effect. The conductivity can reach 1S/cm, and the shielding effect is higher than 30dB. In addition, it has the characteristics of positive temperature coefficient effect and nonlinearity.
Conductive polypropylene is mainly molded into small and light conductors, electromagnetic shielding shells and wallboards by molding (temperature is about 200 ℃, pressure is about 10MPa); It can also be used as high-voltage cable semiconductor layer, anti-static material, temperature, voltage, self-control material, planar heating element, pressure sensitive element, connector, etc.
Electromagnetic shielding polypropylene products are made by mixing polypropylene resin and filler in a certain proportion, then putting them into the plate model, adding a layer of copper mesh in the middle of the material, and making a plate with copper mesh layer in the middle after high temperature and high pressure. It is usually stored in a ventilated and dry place to prevent exposure to the sun and rain and away from fire sources.
Electromagnetic shielding polypropylene product is a white, shiny, flat plate with density
1.51g/cm3, water absorption 0.6%, Brinell hardness 294MPa, tensile strength 76-52.2MPa, bending strength 77.9MPa, impact strength 62kJ/m, good heat resistance (Martin heat resistance 148 ℃), good conductivity (parallel layer resistance 6x10-2 Ω) 63 The electromagnetic shielding effect can reach 68dB (10MHz), and the mechanical strength is also good. Electromagnetic shielding polypropylene products can be machined into large electronic equipment shells requiring electromagnetic shielding and wall panels of large electromagnetic shielding rooms; It is particularly suitable for use as the shell of electronic equipment that requires both shielding function and surface insulation.
The preparation method of magnetic polypropylene is mainly to transfer the dried strontium ferrite (SrO · 6FezOs, particle size 1~2 μ m) Knead it with titanate coupling agent in a certain proportion, then add it into polypropylene resin in a certain proportion, add some auxiliary agent in a proper amount, mix it evenly, mix it with a mixer (either an extruder or an open mill), and then cut it into pieces to make magnetic polypropylene raw materials.
Magnetic polypropylene can be molded into thin magnets, guide magnets, radiant multipolar magnets, micro motors, electromagnetic switches and other products by molding, injection molding or extrusion.
Magnetic polypropylene products have good mechanical strength and magnetic properties, with a density of 3.6g/cm3. The Brinell hardness of the oriented magnetic polypropylene is 1.2x102MPa, the impact strength is 1.5kJ m2, the remanence (B) is 0.21T, the coercive force (H) is 127324A/m, and the maximum magnetic energy product [(BH) max] is 7957.747T · A/m.
Author：admin