During the development of plastics industrialization, the molecular structure and composition of plastic particles are extremely complex, and there are many types, mainly PP, PC, ASB, PVC, PA, PS, SAN, POM, PMMA, etc., and the color of a single material is transparent and translucent. , Slightly yellow and other colors, it is difficult for the general population to identify the actual name style.
As a manufacturer that mainly uses PP and ABS plastic concrete molds, it is necessary for LCMOLDS.COM to briefly explain to customers how to identify such complicated plastic materials. There are only three main methods: appearance identification, density quality identification, and Combustion characteristics to eliminate identification.
Method 1. The method of using hand feel and visual appearance identification
PP, PE, PA have different bendability, smooth hand feeling, soft horny sound when knocking, but different plastic materials such as PS, ABS, PC, PMMA, etc., have no ductility, and feel more rigid and fuzzy , The sound is clearer when struck. Of course, it is totally indistinguishable from this. For example, PE and PP have very similar characteristics, and the single hardness is lower than PP, so you should be more careful in the identification.
The difference between PS and modified PS and ABS is that the former is more brittle, while PS and ABS have better toughness. PS is easy to bend and break, while PS and ABS are not.
PS plastic particles are hard, brittle, colorless and transparent plastic.
PE plastic particles are white and translucent.
SAN plastic particles are slightly blue and transparent.
PC plastic particles are slightly yellow and transparent.
PA plastic particles are light yellow translucent.
PVC plastic is white powder, flakes and granules, while pure PVC is colorless and transparent plastic granules.
Method 2. Use various types of plastic density identification
- PE plastic is 0.91-0.95 grams per cubic centimeter, which can float on water.
- PA plastic has a density of 1.01-1.03 grams per cubic centimeter and is suspended in water.
- PS plastic has a density of 1.05 grams per cubic centimeter and is suspended in water.
- SAN plastic has a density of 1.08 grams per cubic centimeter and sinks in water.
- ABS plastic has a density of 1.06 grams per cubic centimeter and sinks in water.
- POM plastic has a density of 1.42 grams per cubic centimeter and sinks in water.
- PC plastic has a density of 1.20 grams per cubic centimeter and sinks in water.
- PMMA plastic has a density of 1.20 grams per cubic centimeter and sinks in water.
Method 3. Identification method of burning flame and smoke state
- PP plastic burns slowly, the upper part of the flame is yellow, the middle is blue, there is a dripping phenomenon, and there is another paraffin odor after extinguishing.
- The SAN is then slow, and the flame will flash, yellow, and emit black smoke, and there will be a pungent smell when it goes out.
- POM is generally flammable, the flame is pure blue, the plastic melts and turns black, and it has a pungent smell of formaldehyde.
- PA burns slowly and automatically extinguishes after leaving the fire. The top of the flame is yellow and the bottom is blue. When burning, the plastic is easy to foam and has a fruity smell.
- PS, HIPS, and ABS plastics are relatively flammable and continue to burn after leaving the fire. The flame is yellow with dense smoke. When PS and HIPS burn, the surface will foam, and ABS will be in a coked state. PS and HIPS have a floral aroma, while ABS has a special smell.
- PC plastic burns very slowly, and will slowly extinguish after leaving the fire. The flame is yellow with smoke. When burning, PC plastic will soften, foam with carbon black, and have a slight smell of flowers and fruits.
- When PMMA burns, it is light blue with flames and smells of rotten vegetables.
- PVC burns slowly, the flame is yellow and green, black smoke is emitted, and there is a burnt pungent smell.
- PE is flammable, the upper end of the flame is slightly yellow, the lower end is blue, and there is less smoke. After extinguishing, it will smell of paraffin burning.
What needs to be explained is that the above three methods are used, and the basic conditions for the identified plastics are:
- All of the above plastics belong to the discrimination of single plastics. If the plastic particles are mixed and added, it is more difficult to distinguish, and the actual changes are more diverse.
- The performance and combustion performance of processed plastic particles that have been in contact with metal for a long time may undergo chemical changes, which are slightly different from normal conditions.
- When using the smell method to identify, it should be noted that the gas emitted when the fluoro resin and fluoro rubber are burned is toxic.