For a long time, the materials used in automotive filters have been mainly metal, especially ferrous metal materials, but because of the high density of ferrous metal, easy corrosion, no wear-resistant, high processing requirements, so the manufacturing cost is high and the process route is long. Engineering plastics have the advantages of low density, corrosion resistance, high strength, rich source of raw materials, easy molding and processing, low price, good chemical stability, wear resistance and shock absorption, etc., can replace metal structural materials are widely used in electronic and electrical, transportation machinery and equipment and daily necessities. Therefore, it is more and more widely used in the automotive filter industry.

The parts that can be replaced by engineering plastics in the automobile filter are blade ring, diffusion cone, gasoline filter nylon shell, light car air filter shell, swirl tube, center tube, in addition to the end cap, diversion tube, dust cover ash tray, dust collecting tray, plastic mold, water valve, air drain plug and plastic filter element.

The gasoline filter element is not easy to clean, and the assembly resilience is poor, so the integral paper gasoline filter is mostly used. The sealing ring of the original metal filter expands and deforms after being soaked in gasoline, so that the metal shell is charged, which is easy to generate sparks and cause gasoline fire and explosion, which is very dangerous. Integral paper gasoline filter shell shape structure is complex, the wall thickness is only 2 mm, the shell between the upper and lower shells are not allowed to use adhesive, can only use friction welding or ultrasonic welding, and require oil resistance, impact resistance, but also need a certain rigidity, so the use of nylon 66 or polysulfone. Nylon has a high fluidity in the molten state, so this plastic is commonly used to inject thin-walled parts. It has the characteristics of low density, good fluidity, good noise damping, and good heat resistance, chemical resistance and mechanical properties. Chemical drugs, whether weak bases, alcohols, ketones, hydrocarbons or fats, have little effect on its performance. After the integrated paper gasoline filter shell with complex shape is changed to reinforced nylon, the forming process is simple, the cost is low, and the whole is replaced after exceeding the service life, which greatly reduces the cost and saves the waste of metal materials, and has good economic and social benefits.

Engineering plastics have low density, low cost, good use effect, can be replaced at any time as needed, and are ideal alternative materials for some parts in the filter industry. In the future, engineering plastics, including modified polypropylene and modified styrene polymers, will be more and more widely used in the filter industry.