How to distinguish the PP & LDPE?
1.Cosmetic plastic tubePP—100% plastic, polypropylene
Lightweight and tough, easy to process, good heat resistance, high impact strength at room temperature, high tensile strength, good rigidity, corrosion resistance, difficult to paint, folding resistance up to millions of times, excellent electrical function, and large shrinkage. PP, PE, PA are soft and bendable, and have a hard waxy feel to the touch, and a slippery feel. There is a soft horny sound when tapped. PS, ABS, PC, PMMA have no ductility, and the percussive sound is louder. The burning phenomenon of PP is roughly the same as that of PE. There may be a small amount of black ash. After the flame subsides, the smell of oil is between kerosene and the like, which is non-toxic.
2.Cosmetic plastic tubeLDPE-soft rubber, high pressure low density polyethylene
HDPE—hard soft rubber, low pressure high density polyethylene
VHDPE—Super-hard soft rubber, ultra-high pressure polyethylene
Lightweight and tough, easy to process, good heat resistance, good low-temperature toughness, harder and impervious to water, but good abrasiveness, PE is flammable, and can be burned after leaving the fire. The flame is yellow and blue underneath, and there is very little black. Near the flame, the plastic melts and drips, which is similar to the flow of a candle. After the flame subsides, there is a more obvious burning smell of white wax, non-toxic PE. The specific gravity of pp is less than water and floats on water. The vast majority of other plastics have a larger specific gravity than water and sink into water.