PVC - Suspension PVC (2)
DATE：2023/1/6 8:30:30 / READ： / SOURCE：This station
2.3.1.2 - Process characteristics
When PVC resin is used for molding products, a variety of additives need to be added to the resin, otherwise PVC resin will not be able to produce any kind of products. According to the type and quantity of various additives added in the resin during production, the process conditions for plasticizing and melting and the properties of molded plastic products have their own characteristics. The following points should be noted when producing PVC plastic products.① The water absorption of PVC resin is small. If the raw material warehouse out packaging bag is intact and there is no special requirement for product molding, drying treatment is generally not required before the resin is put into production.
② The amount of plasticizer added to the resin can significantly change the properties of the product.
③ There is no obvious melting point temperature when the PVC resin is plasticized in a high temperature environment. The temperature above 80 ℃ starts to soften, 130 ℃ shows a high elastic state, 160 ℃ shows a viscous flow state, and 200~210 ℃ starts to degrade and discolor, while the corrosive gas HCI escapes.
④ For the molding and production of rigid PVC products, in order to improve the fluidity of melt and the high plasticizing temperature of raw materials, it is necessary to select efficient stabilizers in the raw material formula. At the same time, in order to avoid melt fracture, the vehicle speed should be appropriately reduced when necessary.
⑤ During production, it should be noted that some metal ions and oxygen will promote resin degradation, which will be more obvious under high temperature conditions.
⑥ HC1 gas is decomposed during the processing and plasticizing production of PVC, which is corrosive to molds and equipment. The equipment and molds shall be made of alloy steel that is resistant to high temperature, deformation and corrosion.
2.3.1.3 Forming method and use
PVC resin molding plastic products can be processed by extrusion, injection molding, blow molding, calendering, molding, rotational molding, coating and foaming. Processed plastic products include tubes, sheets, plates, films, artificial leather, cable materials, wire sheaths, profiled materials, silk, pipe fittings, skates, bottles, records and transparent films.See Table 2-67 for the main uses of different types of PVC. Refer to Table 2-68 for PVC model and technical index values in Table 2-67.
PVC products are widely used in construction, packaging, electronics, agriculture, automobile, chemical industry and people's daily life. Specific application examples are as follows.
① Construction doors and windows, plates, various profiles, various decorative materials (floor leather, wallpaper), waterproof materials, foam insulation materials and various infusion pipes (domestic water, sewage pipes, etc.).
② Packaging products Packaging films and hollow containers (barrels and bottles, used for packaging food, cooking oil, condiments, various beverages, cosmetics, detergents and various chemical liquids) for food and various crops and industrial products.
③ Insulating materials for electronic and electrical purposes Insulating layers for wires and cables, cable materials, sleeves for wires and batteries, trunking boxes for lines, etc.
④ Application of agricultural production Heat preservation and water conservation ground covering film, greenhouse film, farmland drainage and irrigation pipeline, etc.
⑤ Auto industrial accessories Instrument panel, rear cover, ceiling lining, seat, body lining, protective sleeve, interior floor, etc.
⑥ Materials for chemical industry Pipeline, pipe fitting, valve, pump, chemical equipment lining, electrolytic tank, pickling tank, electroplating tank, reactor, tower and chimney for ventilation, exhaust, transmission of acid and alkali medium and other corrosive liquids in chemical plants. three
⑦ Daily necessities and other daily necessities such as sandals, slippers, coils, pools, raincoats, washing boards, decorative plastic pattern films, tablecloth films, medical containers, handwheels, bolts, mesh, supports, sealing materials, etc.
Author：admin