Packaged foods generally use PP (polypropylene) and PE (polyethylene). These two are relatively safe. The plastic wrap in supermarkets is generally PP, and the hot water pipe at home is also PP, because it is non-toxic. PC (polycarbonate) is generally used for plastic cups that can hold hot water, but Wearable Machinery Al2o3 Alumina Ceramic Insulator Ring this is also used for compact discs, so be careful to recycle waste. PVC is generally used for sewer pipes.
1. Density method: By examining the density of various plastics and using liquid as a medium to see their ups and downs, the category of plastics can be roughly distinguished. Assuming that plastics can float on the surface in water, it can be determined that the raw material is not PVC.
2. Combustion method: observe the color of the flame and the smell and smoke emitted during burning by burning plastic. Generally, the burning flame of polyolefin materials is Wearable Machinery Al2o3 Alumina Ceramic Insulator Ring mostly blue or light blue, the smell is relatively mild and light, and the smoke is white, and most of them are Benzene or chlorine is easy to emit black smoke after burning, and the smell is strong, ABS is just that. In addition, for example, PE and PP have dripping burning, while PVC etc. have no dripping burning, but have self-extinguishing phenomenon.
3. Optical method: Identify by observing the transparency of raw materials. Commonly used transparent raw materials are: PS, PC, PMMA, AS; translucent raw materials are: PE, random copolymer PP, homopolymer PP, soft PVC, transparent ABS, etc. , The other raw materials are basically opaque.
4. Color discrimination method: Generally speaking, raw materials without additives, if they contain double bonds, the color will be slightly yellow, such as ABS, because of the copolymerization of butadiene, the polymer still contains double bonds after polymerization. Therefore, it will be slightly yellow.
1. Polytetrafluoroethylene (PTFE)
Appearance: translucent to opaque, flexible and flexible.
Flammability: non-flammable. A pungent odor (HF) in hot conditions.
2. Polyamide (PA)
Appearance: translucent to opaque.
Flammability: non-flammable, extinguished immediately Wearable Machinery Al2o3 Alumina Ceramic Insulator Ring after leaving the flame. When burning in a flame, there is blue smoke, and the upper end is orange-red; there is melting, dripping, and blistering; you can smell the scorching smell of wool.
3. Polycarbonate (PC)
Appearance: transparent to opaque, hard.
Flammability: flame retardant. Burning in the flame is full of black smoke, bright, charring and foaming; the smell of phenol can be smelled.
4. Phenolic resin (PF)
Appearance: (usually containing fillers) dark color.
Flammability: flame retardant. Burning in the flame can see a bright yellow flame, with a lot of black smoke, cracking and darkening of color.
5. Polyvinyl chloride (PVC)
Appearance: (same as polycarbonate)
Flammability: flame retardant. It burns yellow in the flame, the edge of the flame is green, white smoke; there is softening. Can smell burnt.
6. Amino resin (UF urea/formaldehyde; MF melamine/formaldehyde)
Appearance: (including filler) hard.
Flammability: flame retardant. It is bright yellow Wearable Machinery Al2o3 Alumina Ceramic Insulator Ring when burned in the flame; there are charring, expansion and cracking. Can smell ammonia, formaldehyde, fishy smell.
7. Polyethylene (PE)
Appearance: translucent to opaque, hard; transparent film.
Flammability: combustible in the flame, slowly extinguishes or continues to burn after leaving the flame. When burning, the upper end of the flame is yellow and the lower end is blue; there are melting and dripping phenomena. Can smell paraffin.
8. Polypropylene (PP)
(Appearance and combustibility are the same as polyethylene)
How to identify the ceramic material?
2020 10/12