The spray pressure：700-1500kg/cm2
Water absorption rate（24h）：0.1-0.4%
Melt softening point：89℃
Thermal deformation temperature：70℃
The spray pressure：600-1500 kg/cm2
Water absorption rate（24h）：0.1-0.4%
Melt softening point：85℃
Thermal deformation temperature：55℃
PVC plastics come in different forms and are very different, and the processing methods are also varied, which can be pressed, extruded, injected, coated, etc. PVC resin particle size, fisheye, pine density, purity, foreign impurities, porosity have an impact on processing, paste resin should consider the viscosity and gel properties of paste.
PVC is amorphous high polymer with a small shrinkage. Powder processing should be preheated to remove moisture, enhance the plasticization effect to prevent bubbles. And PVC is very easy to break down, especially at high temperatures with steel, copper contact is easier to decompose (decomposition temperature 200 degrees C). The molding temperature range is small and the temperature must be strictly controlled. When using screw injectors and straight-through nozzles, the aperture should be large to prevent dead-end hysteresis. Mold pouring system should be large, gate cross-section should be large, mold should be cooled, mold temperature 30-60 degrees C, material temperature 160-190 degrees C.
PVC is glass at glass temperature (Tg, 80 degrees C), high elastic rubber at Tg (Tf, approx. 160 degrees C) is highly elastic rubber and malleable, and thermal decomposition temperature (Td) at Tf is a viscous state, the higher the temperature is, the easier it flows. When the temperature exceeds Td, the PVC breaks down a large amount of hydrogen chloride (HCl) and the material loses its chemical stability and physical properties, so Td is the upper limit temperature for machining. Because polyethylene molecules act strongly, Tf is high, or even close to the decomposition temperature, plasticizers need to be added to reduce Tf. On the other hand, a stabilizer needs to be added to improve the Td of PVC in order to be processed and molded.
Glassed temperature (Tg) is only related to the structure of the molecular chain segment, and has little to do with molecular weight, while the viscous flow temperature (Tf) is the temperature at which the large molecule begins to move, which is related to the size of the molecular weight, the larger the molecular weight, the higher the Tf. Therefore, for some process molding (e.g. injection molding), it is necessary to reduce the molecular weight of the resin appropriately. Depending on the size of the molecular weight, domestic suspended PVC resin is divided into 1-7 grades, the larger the serial number, the smaller the molecular weight. XJ-4 (XS-4) to XJ-7 (XS-7) resin is often used in the manufacture of tubes, hard plates, etc. , other models are lower, the molecular weight of the larger resin, because Tf is higher, need to add a large number of plasticizers to reduce Tf, so often used in the manufacture of soft products.
PVC with an average polymerization of less than 1000 is called low polymerization PVC, which has good processing performance and can be added less plasticizer during processing, so that the product will not age at an accelerated rate due to the migration of plasticizer. Low polymerization PVC products have good transparency and are widely used in building materials, food and pharmaceutical packaging materials, as well as in the replacement of plexiglass products.
PVC melt is a non-Newtonian pseudofluor, the greater the shear speed is, the smaller the apparent viscosity is, and the change is quite sensitive. Raise the temperature, viscosity is not much, even if the plastic is below the decomposition temperature, but because of a long time at a higher temperature, will also heat and oxidation degradation phenomenon, and affect its performance. Therefore, improving the fluidity of PVC melt should mainly consider increasing the shear rate (increasing pressure). In fact, increasing the external force helps the movement of the polymer, which reduces Tf and allows the large molecule to flow at a lower temperature.
- Profile material
Profiles and profiles the largest sector among many PVC products, accounting for about 25% of the total PVC consumption, mainly used in the production of doors and windows and energy-saving materials, its application volume in the country still has a relatively large increase. In developed countries, plastic doors and windows also have the highest market share, such as Germany 50%, France 56%, the United States 45%.
- PVC pipe
PVC pipelines are the second largest sector among many PVC products, accounting for about 20% of PVC total consumption. PVC pipe than PE tube and PP tube were development early, they have many varieties, excellent performance, a wide range of use, are important in the market..
- PC film
PVC film is the third largest seller in the PVC market, accounting for about 10%. After the PVC is mixed with additives and plasticized, a three-roll or four-roll rolling mechanism is used to form a transparent or colored film with a specified thickness, and the method is processed into a roll film. It can also be cut, heat-treated bags, gloves, raincoats, yoga balls, tablecloths, jump ropes, curtains, ab wheels, inflatable toys, etc. The wide transparent film can be used in greenhouses, plastic sheds and films. A biaxially oriented film with heat shrinkability can be used for shrink packaging.
- PVC hard material and plate
PVC, if added stabilizers, lubricants and fillers, after mixing, the extruder can be extruded from a variety of caliber tubes, special tubes, bellows, used as sewers, drinking water pipes, wire casings or stair handrails. The pressed sheets are recompressed and hot-pressed to make hard sheets of various thicknesses. Plates can be cut into the desired shape and then welded with hot air using PVC welding rods into a variety of chemically resistant tanks, ducts and containers.
- PVC general soft products
The extruder can squeeze PVC into hoses, wires, cables, etc. Injection molding machines with various molds can make PVC into plastic sandals, fitness equipment, custom yoga mat accessories, shoe soles, slippers, mobile phone cases, toys, auto parts, etc.
- PVC packaging materials
PVC products are used for packaging, mainly for various containers, films and rigid sheets. PVC film can be used to extrude laminates with other polymers at a lower production cost, as well as transparent products with good barrier properties. PVC film can also be used for stretch or heat shrink packaging, mattresses, fabrics, toys and industrial products.
- PVC wall panels and floors
PVC wall panels are mainly used to replace aluminum wall panels. PVC floor tiles, with the exception of some PVC resins, are recycled materials, adhesives, fillers and other components, mainly used on the ground floor of the airport terminal and other places of hard ground.
- PVC consumer goods
Bags are traditional products made from processed PVC, which is used to make a variety of imitation leathers for luggage, sports products such as basketball, football and football. It can also be used to make belts for uniforms and special protective equipment. PVC fabrics for clothing are generally adsorption fabrics (no coating required), such as ponchos, baby pants, faux leather jackets and various rain boots. PVC is used in many sports entertainment products, such as toys, records and sporting goods, and PVC toys and sporting goods have grown significantly, owing to their low production costs and easy molding.
- PVC coated products
The artificial leather with the base material is coated on cloth or paper, and then plasticized at a temperature above 100 degrees Celsius. It is also possible to press PVC and additives into a film, and then press it into a substrate. The leather without the substrate is directly stretched into a flexible sheet with a certain thickness through a roller press, and then the pattern is pressed. Artificial leather can be used to make boxing gloves, suitcases, belts, wallets, book covers, slippers, sofas and car cushions, and can also be used as floor materials for construction.
- PVC foam products
When mixing soft PVC and adding the right amount of foaming agent to make a sheet, foam molded into foam, can be used as foam slippers, sandals, insoles, and shock-proof buffer packaging materials. It can also be used to form low foam hard PVC plate and special profile, which can be used as an alternative to wood, and is a new type of building material.
- PVC transparent sheet
If PVC is added to the shock absorber and organotin stabilizer, mixed, plasticized and pressed, it can become a transparent sheet. Thermoforming can be made into transparent thin-walled containers, and can also be used for vacuum blister packaging. It is an excellent packaging material and decoration material.
- Other use
Doors and windows are made of hard, special materials. In some countries, we have jointly occupied the market of doors and windows with wooden doors and windows, such as aluminum windows;
Virtual circuit is one of the services provided by packet switching network (the other is data reporting service), in short, through the control mechanism within the network, establish a virtual logical connection between the user host, and ensure the correctness and order of transmitting the packet on it, before and after the communication to carry out the establishment and dismantling of virtual circuit. A permanent virtual circuit is a virtual circuit established when the network is initialized, and the virtual circuit remains. Both the X.25 network and B-ISDN offer PVC services. PVC plastic bags are generally disabled.
Speck, the leading fitness product manufacturer, purchases a large amount of high-quality PVC every year to manufacture jump ropes and other products.
New Materials Research
Plastics have been used in the automotive industry for more than 50 years. With the development of automobile to lightweight and energy-saving direction, higher requirements are put forward for materials. Since 1kg plastic can replace heavier materials such as 2-3kg steel, fuel consumption can be reduced by 6%-8% for every 10% drop in car self-weight. Therefore, increasing the amount of modified plastics in the car can reduce the cost, weight, and achieve energy-saving effect. Different plastic dosages vary from passenger and commercial vehicle to commercial vehicle. Last year, the demand for modified PPs, PC alloys and modified ABS was about 114.63, 15.13 and 149.7 million tons, respectively.
1.PVC replaces steel
Through the research of PVC modification technology, the advanced internal plasticization technology and additive formulation abroad are used to ensure the mechanical and electrical properties of PVC plastic steel, improve flame retardant performance, so that the product has the advantages of high strength, corrosion resistance, flame resistance, good insulation performance and light quality and convenient construction. Steel pipes can be completely replaced in electrical wiring systems.
- PVC replaces timber
PVC wood plastic composite material is a new type of composite material prepared by heat pressing preparation process with waste wood fiber and plastic main raw materials, supplemented by appropriate processing aids. Its products fully reflect the concept of recycling of renewable resources and petroleum products, which is of great significance for alleviating the current shortage of timber and petroleum resources and serious environmental pollution.  Industry experts pointed out that the PVC building materials to plastic wood, which not only save costs, but also recyclable, in line with the environmental sustainable development and circular economy trend.
- Synthetic materials
PVC, or PVC for short, is a thermoplastic resin. PVC futures are also futures varieties with PVC as the target. Plastics: polyethylene; PVC; polystyrene; polyethylene alcohol; polypropylene; polyacrylic; polybutene; polysobutene; polyurethane; polyformaldehyde; polyamide; polycarbonate; polylactic acid; polytetrafluoroethylene; polyphenyl ethylphenate; epoxy resin; phenolic resin; polyurethane Synthetic rubber: shunbutyl rubber; butyl rubber; butyl rubber; neoprene Synthetic fibers: acrylic; polyester; nylon; acrylic; spandex; vinyl; nylon; daklun; kovlon
The general identification methods of PVC are generally summarized into three categories :
Soften or melt the temperature range：75~90°C；
Burning condition: self-extinguishing after ignition；
Burning flame state: smoke in the upper yellow and green; off the fire extinguished; Irritating acidity
This method is the easiest and most straightforward and is generally preferred
(2) Solvent treatment：
Solvents: tethionolfuran, cyclohexone, methadone, dimethylmethamide; Non-solvent: methanol, acetone, etan. By adding the suspected PVC plastic to the above solvent, observe the dissolution of the plastic to determine whether it is PVC. When the solvent is heated, the dissolving effect is more obvious.
The proportion of PVC is 1.35 to 1.45, which is generally about 1.38. PVC and other plastics can be distinguished by specificity differences or by measuring specific gravity. However, because PVC can be added plasticizers, modifiers and fillers, so that PVC becomes a large proportion of differences, hard and soft differences, but also due to the addition of some components, so that many of the performance of PVC plastic changes, resulting in our commonly used identification method effect is not obvious, or even change the phenomenon, can not make an accurate judgment. For example, in terms of density, PVC (about 40% plasticizer) is 1.19 to 1.35, while PVC hard products are increased to 1.38 to 1.50. In the case of high-fill PVC products, the density sometimes exceeds 2.
In addition, it can also be determined by determining whether chlorine is found in the material, but because vinyl chloride copolymers, neoprene, PVC, PVC, etc. all contain a higher proportion of chlorine, but also through the color rendering reaction to identify. Note that before the test, the reagent must be extracted by ether to remove the plasticizer, test method: the sample taken by ether benzene dissolved in tetrahydrofuran, filter out the insoluble ingredients, add methanol to make it precipitate, after extraction before 75 degrees of drying. A small sample that has been dried does not need 1mL of radon to react with it, after a few minutes, add 2 to the field drop 5% sodium hydroxide methanol solution (1g sodium hydroxide dissolved into 20mL methanol), immediately observe the color, 5min and 1h and then observe again. Different chlorine-containing plastics can be identified by color.
In daily life, there is a need to distinguish between PVC and PE plastic film (bag), simple method:
With a sense of lubrication felt by hand, the surface is coated with a layer of wax (chemically called wax), which is a non-toxic polyethylene film bag, while PVC film feels a bit sticky.
- Jitter method Shake by hand
The sound is crisp, the texture easily floats is polyethylene film bag. The low-sounding hand shaker is the PVC film bag.
(3) Burning method In case of flammable fire, the flame is yellow, when burning paraffin-like oil drops, and candles when burning gas, is non-toxic polyethylene film bag. If not easy to burn, the fire is extinguished, the flame is green, PVC film bag
The plastic bag is immersed in water, pressed into the water by hand, can surface for polyethylene, sink into the bottom of the water is PVC (polyethylene density is less than water, PVC density is greater than water; at room temperature is about 0.92g/cm3 and 1.4g/cm3, respectively). Copper wire can also be taken, burned red in the fire, and then, the copper wire and the test plastic film contact, resulting in chemical changes, and then the copper wire with the plastic composition back into the flame. At this time, it is necessary to carefully observe, if there is a colorful, dazzling green flame, it is indicated that this plastic material contains chlorine, belongs to the PVC material.
PVC is also a commonly used plastic, it is a PVC resin, plasticizers and anti-aging agent resin, itself non-toxic. However, the addition of plasticizers, anti-aging agents and other major accessories toxic, daily PVC plastic plasticizer, mainly the use of benzodiazepines, phthalates, etc. , these chemicals are toxic, PVC anti-aging agent lead stearate is also toxic. Lead is precipitated in PVC products and in contact with ethanol, ether and other solvents. Lead-salted PVC is used as food packaging and oil bars, fried cakes, fried fish, cooked meat products, cake snacks meet, will make lead molecules spread to grease, so can not use PVC plastic bags to pack food, especially can not contain oily food. In addition, PVC plastic products at higher temperatures, such as around 50 degrees C will slowly break down hydrogen chloride gas, this gas is harmful to human health, so PVC products should not be used as food packaging.
Because most disposable medical device products use medical grade PVC or polycarbonate (PC), and PVC processing process of thermal decomposition of steel has a strong corrosive, PC is high hardness, viscosity, so the plastic parts material requirements must be anti-corrosion, anti-wear and high polishing performance. Most medical injection molding machines use the hard chrome-plated method of the barrel screw or the use of stainless steel as the material to make the machine simple screw to meet the above special requirements. In addition, in order to prevent the thermal decomposition of the PVC processing process to produce gas, the dynamic template surface is required to be aluminum-plated treatment, and the peripheral plate gold is also aluminum-plated treatment or the use of stainless steel plate plate gold, plate gold seam using non-toxic silicone seal, in order to prevent the plastic processing process generated by the gas to run outside (plastic processing process generated by the gas can be collected centrally through special equipment and then purified before discharge into the atmosphere).
PVC is the main source of dioxins. Dioxin (TCDD), the deadliest substance in the family of Dioxane, is a well-known carcinogen and hormone breaker and a toxic compound that is harmful to humans and animals. Dioxins are produced when PVC is produced, recycled and destroyed in incinerators, or when PVC products are accidentally burned, such as landfills.