1. The history and status quo of plastic extrusion molding technology
As one of the polymer processing technologies, extrusion molding technology has grown with the development of polymer processing industrial technology.
In the 1950s, the development of petrochemical industry made the polymer industry mature rapidly; in the 1960s, the production of the three major synthetic materials of plastics, rubber, and chemical fiber changed to large-scale; in the 1970s, the total volume of synthetic polymer materials in the world had exceeded metallic material. Polymers can become valuable products only through molding and processing. Forming processing is an indispensable production link for polymer materials.
Extrusion molding, as an important technology in the polymer processing industry, is developed by mutual promotion and interdependence in polymer resin application engineering technology and extrusion production equipment development technology. Various extrusion products include: early hard PVC pipes, coated cables, PS, PP and ABS sheets and plates, PE blown films and coated films, etc.; today’s PVC profiles, cross-linked PE, aluminum-plastic composites, RP pipe, biaxially oriented polypropylene film, multi-layer co-extruded composite film, film with special properties such as high barrier properties, air permeability, self-adhesiveness, heat shrinkage, and self-elimination, functional masterbatch and color masterbatch, Foam products. The use of extrusion processing methods to prepare modified polymer materials, blending reinforcement, toughening technology, radiation modification technology, nanocomposite technology, and other new modification technologies. Extruders with various structures and functions, such as mixing screw extruders, vented extruders, twin-screw, multi-screw extruders, reactive extruders, combined extruders, suitable for polymer materials The molding device established by physical and chemical characteristics has the specialized functions required by various products, and the auxiliary equipment of the extrusion line that can implement the molding steps. It is continuously improved in pursuit of the goals of simple operation, precise control, energy saving, high efficiency, and clean production. New equipment.
At present, the extrusion molding technology of many products has developed into a specialized set of technology including production process and production line equipment. The products are of high quality and good economic benefits can be obtained. Although the period of rapid development of new processing methods and theories in extrusion molding has passed, and it is now in a period of much higher levels than in the past and the development is flat, but in the application of these technologies, continuous innovation can still be made. Develop new products, manufacture new materials, and form new technologies.
2, the use of plastic extrusion molding products
Extrusion can process part of thermosetting plastics and most of thermoplastics and elastomers.
Extrusion products mainly include films, pipes, sheets, profiles, rods, wires, nets, belts, wires, cable coatings, hollow containers, foam plastics, composite materials, etc. They are widely used in various sectors of the national economy.
Packaging materials are one of the important uses of extruded products. Various films, composite materials, hollow containers, woven bags, nets, packing belts, strapping ropes, etc. are widely used in food, agricultural and sideline products, textiles, food, medicine, chemical products, fertilizers, cement, precision instruments, daily necessities, sporting goods, Packaging of stationery, etc.
In agriculture, the extensive use of plastic film seedlings and greenhouse planting can shorten the growth period of crops, increase yields, and increase farmers’ income. For example, rice seedlings can be harvested 15-20 days earlier, with an increase of 100-200kg per mu. The solar greenhouse can make fresh vegetables available all year round in the cold north. Plastic pipes can be used for irrigation and drainage of farmland, and plastic nets can be used in aquaculture to greatly increase the output of pearls and fresh scallops. It can also be used in fishing and aquaculture.
In the machinery manufacturing industry and transportation industry, plastic products are also widely used. Plastic rods can be processed into mechanical parts such as bearings, gears, and pipe fittings. Various plastic pipes, plates, and profiles are used to manufacture various dashboards, door inner walls, fender linings, water pipes, oil pipes, air pipes, decorative parts, doors, windows, roofs, armrests, floors, etc.
Due to the excellent chemical resistance of plastic products, in the chemical industry, a large number of plastic pipes, plates, rods, and hollow containers are used as anti-corrosion materials to manufacture various tanks, tanks, kettles, pipes, pumps, fans, towers, etc. Lining and packing save a lot of metal materials. For example, 1t plastic can replace 6~7t stainless steel, copper and other metals.
In the electronics and telecommunications industries, taking advantage of the good electrical insulation properties of plastics, a large number of plastics are used as insulating materials, such as insulating layers and protective layers of wires and cables, insulating parts of various electrical appliances, and insulating plates.
The construction industry is increasingly using plastic sheets and profiles to manufacture doors and windows, floors, wall panels, roof panels, water pipes, sound insulation materials, furniture, etc.
In the medical and health industry, plastic film and tubing can be used to manufacture blood transfusion bags, blood transfusion tubes, oxygen tubes, esophagus, urethra, and surgical instruments.
The plastic products used in daily life are even more dazzling.