In daily life, people contact more plastic bags (film), the general PVC (PVC) and polyethylene (PE) plastic film (bag), how to distinguish between the two of them, the following summary of several simple methods :
⑴ touch method
Hand touching a sense of lubrication, the surface painted like a layer of wax (chemical known as wax sense), which is non-toxic polyethylene film bags, and PVC film is some sticky sticky.
⑵ jitter method
Hand shake, sound crisp, easy to float the polyethylene film bag. While the hand shake the voice of the low is the PVC film bag.
⑶ combustion method
In case of fire flammable, the flame was yellow, burning with paraffin oil dripping, and the candle burning gas, is a non-toxic polyethylene film bag. If not easy to burn, from the fire that is extinguished, the flame was green, for the PVC film bag.
⑷ immersion method
The plastic bag immersed in water, hand pressed into the water, can surfaced for the polyethylene, sink into the bottom of the polyvinyl chloride (polyethylene density is less than water, PVC density is greater than water; at room temperature were about 0.92 g / cm3 and 1.4 g / cm3).
In addition, you can also take a copper wire, burned in the fire red, and then the copper wire and test plastic film contact, resulting in chemical changes, then dipped in the plastic composition of the copper wire back into the flame. At this time to be carefully observed, if there are colorful, dazzling green flame, then this plastic material contains chlorine, belonging to the PVC material.
PVC and ordinary plastic difference
The biggest difference:
1, PVC processing dependence on some of the additives is very large, PVC resin powder itself can not be directly processed into any product, must add stabilizers, lubricants, processing aids, soft plastic products in the plastic is also necessary.
2, PVC resin itself and other general plastic, in the synthesis process heavy, can not rely on petroleum by-products, so it is almost the same as the oil industry chain is not like other general plastic.
3, PVC materials in the building materials reuse is relatively large, because he has a clear advantage, that is, outdoor use process, because of its different decomposition mechanism, its own physical performance decreased to a relatively small extent, and the price is relatively low.
The characteristic performance of pvc plastic bag
PVC (polyvinyl chloride) chemical and physical properties Rigid PVC is one of the most widely used plastic materials. PVC material is a non-crystalline material. PVC materials in the actual use of often added stabilizers, lubricants, auxiliary processing agents, colorants, impact agents and other additives.
PVC material with non-flammability, high strength, weather resistance and excellent geometric stability. PVC has a strong resistance to oxidants, reducing agents and strong acids. However, it can be concentrated oxide acid such as concentrated sulfuric acid, concentrated nitric acid corrosion and does not apply with aromatic hydrocarbons, chlorinated hydrocarbons in contact with the occasion.
PVC melting temperature during processing is a very important process parameters, if this parameter will lead to improper decomposition of the material. PVC flow characteristics are quite poor, the process range is very narrow. In particular, large molecular weight PVC materials are more difficult to process (this material is usually added to the lubricant to improve the flow characteristics), so are usually used are small molecular weight PVC material. PVC shrinkage is quite low, generally 0.2 to 0.6%.