Pvc boards have some harm to the human body. pvc is also known as polyvinyl chloride, is often used in a plastic, it is made of polyvinyl chloride resin, plasticizer and antioxidant composition of the resin, itself is not toxic.
But the added plasticizer, antioxidant and other major auxiliary materials have toxicity, daily use of polyvinyl chloride plastic in the plasticizer, mainly using dibutyl terephthalate, dioctyl phthalate, etc., these chemicals have toxicity, polyvinyl chloride antioxidant stearic acid lead salt is also toxic.
Polyvinyl chloride (PVC) products containing lead salt antioxidant and ethanol, ether and other solvents will precipitate lead in contact. PVC containing lead salts is used as food packaging to meet doughnuts, fried cakes, fried fish, cooked meat products, cakes and snack foods.
It will make the lead molecules diffuse into the grease, so you can not use polyvinyl chloride plastic bags to contain food, especially can not contain oil-based food.
In addition, PVC plastic products at higher temperatures, such as about 50 ℃ will slowly decompose hydrogen chloride gas, this gas is harmful to the human body, so PVC products should not be used as food packaging.
Since most disposable medical device products are made of medical-grade polyvinyl chloride (PVC) or polycarbonate (PC), while the thermal decomposition of PVC during processing is highly corrosive to steel, PC has high hardness and high viscosity.
Therefore, the plasticizing part of the parts material requirements must be able to resist corrosion, wear and have a high degree of polishing performance. Most of the medical injection molding machine using barrel screw hard chrome plating or stainless steel as the material for the production of machine screw to achieve the above special requirements.
In addition, in order to prevent the thermal decomposition of PVC processing gas, the requirements of the dynamic fixed template surface aluminizing treatment, but also on the periphery of the plate gold also aluminizing treatment or stainless steel plate production plate gold, plate gold seams using non-toxic silicone sealing.
To prevent the gas generated during the plastic processing to the outside (the gas generated during the plastic processing can be collected through special equipment and then purified before being discharged into the atmosphere).
PVC is the main source of dioxins. Dioxin (TCDD), the deadliest substance in the dioxin (hetero)dioxin family, is a well-known carcinogen and hormone decomposer and a toxic compound, which is very harmful to humans and animals.
Dioxins are produced when PVC is manufactured, recycled and destroyed in incinerators, or when PVC products are accidentally burned as in landfills.
Expanded information:
One, identify PVC and PE plastic film (bags), simple methods
1, touch method
Touching the hand has a Lubrication, the surface like a layer of wax coated (chemically known as wax sense), which is non-toxic polyethylene film bags, while the PVC film is a little sticky to the touch.
2, shaking method
Shaking with the hand, the sound of brittle, the quality of easy to float is a polyethylene film bags. And shake with the hand of the sound of the low polyvinyl chloride film bags.
3, combustion method
Inflammable in the event of fire, the flame is yellow, burning paraffin oil dripping, and candle burning gas, is a non-toxic polyethylene film bags. If it is not easy to burn, off the fire that is extinguished, the flame is green, for the polyvinyl chloride film bags.
4, immersion method
Plastic bags will be immersed in water, hand pressure into the water, can float out of the water for the polyethylene, sank to the bottom of the water for the polyvinyl chloride (polyethylene density is less than the water, the density of polyvinyl chloride is greater than the water; room temperature, respectively, for about 0.92g/cm3 and 1.4g/cm3).
Copper wire can also be taken one, burned in the fire into red, and then, the copper wire and test plastic film contact, chemical changes, and then dipped in the plastic composition of the copper wire back into the flame.
Then you need to carefully observe, if there is colorful, dazzling green flame, it shows that this plastic material contains chlorine, belonging to the polyvinyl chloride class materials.
Two, the main use of PVC
1, PVC profiles
Profiles, profiles is the largest consumption of PVC in China in the field, accounting for about 25% of the total consumption of PVC, mainly used for the production of windows and doors and energy-saving materials, the amount of its application in the country is still a relatively large increase. In developed countries, the market share of plastic doors and windows is also high, such as Germany for 50%, France for 56%, the United States for 45%.
2, polyvinyl chloride pipe
In many polyvinyl chloride products, polyvinyl chloride pipe is its second largest consumption area, accounting for about 20% of its consumption. In our country, PVC pipe is developed earlier than PE pipe and PP pipe, with many varieties, excellent performance, wide range of use, and occupies an important position in the market.
3, polyvinyl chloride film
PVC film field of PVC consumption ranks third, accounting for about 10% or so. PVC and additives mixed, plasticized, using three-roller or four-roller calender to make the required thickness of transparent or coloring film, with this method of film processing, become calendered film.
Can also be cut, heat-laminated processing bags, raincoats, tablecloths, curtains, inflatable toys and so on. Wide transparent film can be used for greenhouses, plastic greenhouses and mulch. The bi-directional stretching of the film, the characteristics of heat shrinkage, can be used for shrink-wrapping.
4, PVC hard materials and plates
PVC in the addition of stabilizers, lubricants and fillers, after mixing, with the extruder can be extruded in various calibers of hard pipe, profiled pipe, corrugated pipe, used as downpipes, drinking water pipes, wire casing or staircase handrails.
The calendered sheets are overlapped and hot pressed to make various thicknesses of hard sheets. The sheets can be cut into desired shapes, and then welded into various chemical-resistant storage tanks, ducts and containers with hot air using PVC welding rods.
5, PVC general soft goods
The use of extruders can be extruded into hoses, cables, wires, etc.; the use of injection molding machines with a variety of molds, can be made into plastic sandals, soles, slippers, toys, car parts, etc..
Reference:
Baidu Encyclopedia-PVC