What is PVC plastic?
PVC plastic refers to the compound polyvinyl chloride in the chemical field. Its natural color is yellowish, translucent and shiny. Better than PE, PP, lost to PS. It is a polymer material, which uses chlorine atoms to replace hydrogen atoms in polyethylene.
Main properties of PVC plastics:
Chemical and Physical Properties of PVC Rigid PVC is one of the most widely used plastic materials. PVC material is an amorphous material. Additives such as stabilizers, lubricants, auxiliary processing AIDS, pigments and reinforcing agents are often added to PVC materials in practical use [1].
PVC material is nonflammable, with high strength, good weather resistance and excellent geometric stability. PVC has strong resistance to oxidants, reductants and strong acids. However, it can be corroded by concentrated oxidizing acids such as concentrated sulfuric acid and concentrated nitric acid, and is not suitable for contact with aromatic hydrocarbons and chlorinated hydrocarbons.
The melting temperature of PVC during processing is a very important technological parameter. If this parameter is not suitable, it will lead to the problem of material decomposition. PVC has poor fluidity and narrow processing range. In particular, PVC materials with large molecular weight are more difficult to process (this material usually needs to add lubricants to improve its flow characteristics), so PVC materials with small molecular weight are usually used. The shrinkage of PVC is quite low, generally 0.2~0.6%.
Technological conditions of injection mold
Melting temperature: 185~205℃ Mold temperature: 20~50℃
Injection pressure: up to 1500bar holding pressure: up to 1000bar injection speed: In order to avoid material degradation, it is generally necessary to use a considerable injection speed.
Runner and gate: All conventional gates can be used. If machining smaller parts, it is best to use needle gate or submerged gate; For thicker parts, it is best to use fan gate. The minimum diameter of needle gate or submerged gate should be1mm; The thickness of the sector gate should not be less than 1 mm.
Typical use water supply pipeline, household pipeline, house wallboard, commercial machine shell, electronic product packaging, medical equipment, food packaging, etc.
Main uses of PVC plastics:
1, PVC profile
Profile and profile are the largest areas of PVC consumption in China, accounting for about 25% of the total PVC consumption. They are mainly used to make doors and windows and energy-saving materials. At present, their applications are still increasing in a large number throughout the country. In developed countries, the market share of plastic doors and windows is also the highest, such as 50% in Germany, 56% in France and 45% in the United States.
2. PVC pipes
Among many PVC products, PVC pipe is the second largest consumption field, accounting for about 20% of its consumption. In China, PVC pipes have developed earlier than PE pipes and PP pipes, with many varieties, excellent performance and wide application range, and occupy an important position in the market.
3. PVC film
The consumption of PVC in the field of PVC film ranks third, accounting for about 10%. After PVC and additives are mixed and plasticized, they are made into transparent or colored films with specified thickness by a three-roll or four-roll calender, and processed into calendered films by this method. You can also cut heat-sealed packaging bags, raincoats, tablecloths, curtains, inflatable toys, etc. Wide transparent film can be used in greenhouses, plastic greenhouses and plastic films. Biaxially stretched film can be used for shrink packaging because of its thermal shrinkage.
4.PVC hardwood and board
Stabilizers, lubricants and fillers are added to PVC. After mixing, hard pipes, special-shaped pipes and corrugated pipes with various diameters can be extruded by an extruder to be used as sewer pipes, drinking water pipes, wire sleeves or stair handrails. By overlapping and hot-pressing calendered sheets, hard plates of various thicknesses can be manufactured. The plate can be cut into the required shape, and then welded with hot air and PVC covered electrode into various chemical corrosion-resistant storage tanks, air ducts and containers.
5, PVC general soft goods
The extruder can be used to extrude hoses, cables, wires, etc. Plastic sandals, soles, slippers, toys, auto parts, etc. can be made by injection molding machine with various molds.
6. PVC packaging materials
PVC products are mainly used for packaging various containers, films and hard sheets. PVC containers mainly produce PTP packaging of mineral water, beverages, cosmetic packaging bottles and medicines, as well as packaging of refined oil. PVC film can be used for extrusion with other polymers to produce low-cost laminated products and transparent products with good barrier properties. PVC film can also be used for stretching or heat shrinking packaging, and used for packaging mattresses, fabrics, toys and industrial products.
7.PVC wallboard and floor
PVC wallboard is mainly used to replace aluminum wallboard. PVC floor tiles not only contain part of PVC resin, but also contain recycled materials, adhesives, fillers and other components, which are mainly used for hard floors in airport terminals and other places.
8. PVC consumer goods
Luggage is a traditional product made of PVC. PVC is used to make all kinds of imitation leather, used in bags and sporting goods, such as basketball, football and rugby. It can also be used to make uniform belts and special protective equipment. PVC fabrics for clothing are generally water-absorbent fabrics (uncoated), such as ponchos, baby pants, imitation leather jackets and various rain boots. PVC is used in many sports and entertainment products, such as toys, records and sporting goods. At present, PVC toys have increased greatly, which has advantages because of its low production cost and easy molding.
To know the formula and design of PVC plastics, please refer to the related article (PVC Plastics Formula and Design /News/News/23663.html).