Introduction to PVC
PVC is the abbreviation of polyvinyl chloride, the English name is Polyvinylchloride, the main component is polyvinyl chloride, bright color, corrosion resistance, strong and durable, due to the addition of some toxic auxiliary materials such as plasticizers and anti-aging agents in the manufacturing process to enhance Its heat resistance, toughness, ductility, etc., so its products PVC boxes generally do not store food and medicine.
In terms of chemical and physical properties, rigidity is one of the most widely used plastic materials. PVC material is an amorphous material. In actual use, stabilizers, lubricants, auxiliary processing agents, colorants, impact agents and other additives are often added.
PVC material has non-flammability, high strength, weather resistance and excellent geometric stability. It has strong resistance to oxidants, reducing agents and strong acids. However, it can be corroded by concentrated oxidizing acids such as concentrated sulfuric acid and concentrated nitric acid and is also not suitable for the occasions in contact with aromatic hydrocarbons and chlorinated hydrocarbons.
The melting temperature of PVC during processing is a very important process parameter. If this parameter is improper, it will cause the problem of material decomposition.
The flow characteristics of PVC are quite poor, and its process range is very narrow. Especially PVC materials with large molecular weight are more difficult to process (this kind of material usually needs to add lubricant to improve the flow characteristics), so PVC materials with small molecular weight are usually used. The shrinkage rate of PVC is quite low, generally 0.2~0.6%.The main uses and industrial chain of PVC
1. PVC profile
Profiles and profiled materials are the areas with the largest PVC consumption in my country, accounting for about 25% of the total PVC consumption. They are mainly used in the production of doors, windows and energy-saving materials. At present, their application volume still has a large increase nationwide. In developed countries, the market share of plastic doors and windows also ranks first, such as 50% in Germany, 56% in France, and 45% in the United States.
2. PVC pipe
Among the many PVC products, PVC pipes are its second largest consumer field, accounting for about 20% of its consumption. In my country, PVC pipes are developed earlier than PE pipes and PP pipes. They have many varieties, excellent performance, and a wide range of use. They occupy an important position in the market.
3. PVC film
The consumption of PVC in the PVC film field ranks third, accounting for about 10%. After mixing and plasticizing PVC with additives, a three-roller or four-roller calender is used to make a transparent or colored film with a specified thickness, and the film is processed by this method to become a rolled film. It can also be cut and heat-sealed into bags, raincoats, tablecloths, curtains, inflatable toys, etc. The wide transparent film can be used in greenhouses, plastic greenhouses and mulch films. The biaxially stretched film can be used for shrink packaging due to the heat shrinkage characteristics.
4. PVC hard materials and plates
Stabilizers, lubricants and fillers are added to PVC. After mixing, extruders can be used to extrude hard pipes, special-shaped pipes and corrugated pipes of various calibers. They can be used as sewer pipes, drinking pipes, electric wire bushings or stair handrails. . The calendered sheets are overlapped and hot pressed to make hard plates of various thicknesses. The sheet can be cut into the required shape, and then welded with hot air into various chemically resistant storage tanks, air ducts and containers using PVC welding rods.
5. General soft PVC products
The extruder can be used to extrude hoses, cables, wires, etc.; the injection molding machine can be used with various molds to make plastic sandals, soles, slippers, toys, auto parts, etc.
6. PVC packaging materials
PVC products are mainly used for packaging various containers, films and hard films. PVC containers mainly produce PTP packaging for mineral water, beverages, cosmetics bottles, and medicines, as well as packaging for refined oils. PVC film can be used for co-extrusion with other polymers to produce low-cost laminates and transparent products with good barrier properties. Polyvinyl chloride film can also be used for stretch or heat shrink packaging, used for packaging mattresses, cloth, toys and industrial commodities.
7. PVC wall panels and floors
Polyvinyl chloride wallboard is mainly used to replace aluminum wallboard. Except for a part of PVC resin in PVC floor tiles, the rest of the components are recycled materials, adhesives, fillers and other components, which are mainly used on the airport terminal floor and other hard floors.
8. PVC consumer goods8. PVC consumer goods
Luggage bags are traditional products made by processing PVC. PVC is used to make various imitation leathers for luggage bags and sports products such as basketball, football and rugby. It can also be used to make uniforms and belts for special protective equipment. PVC fabrics for clothing are generally absorbent fabrics (no coating required), such as ponchos, baby pants, imitation leather jackets and various rain boots. Polyvinyl chloride is used in many sports and entertainment products, such as toys, records and sports goods. At present, the growth of polyvinyl chloride toys is large. Due to the low production cost of polyvinyl chloride toys and sports goods, it is easy to form and has an advantage.