Here are some ways to distinguish the material of food plastic bags:
Observe the appearance
Transparency
PET: very high transparency, similar to glass, can clearly see the details of the food inside the bag, and the gloss is also very good.
LDPE: usually semi-transparent, with a certain haze, but can better show the outline of the food, soft to the touch.
HDPE: usually opaque or translucent, slightly less transparent than LDPE, relatively hard texture.
PP: usually translucent state, transparency between LDPE and PET, the surface has a certain gloss.
EVA: Higher transparency, similar to LDPE, but usually softer and more flexible.
Color
Generally speaking, food plastic bags are colorless and transparent or white, but different materials may have some slight color differences. For example, PP material may have a slight yellowish tint, while PE material is usually more creamy or colorless.
Touch Feeling
Hardness
HDPE: Harder to the touch, has a certain degree of rigidity, is not easy to deform when pressed by hand, and has a high degree of strength, not easy to tear.
PP: Hardness is slightly lower than HDPE, but harder than LDPE, with a certain degree of toughness, after bending can be restored to its original state faster.
LDPE: soft texture, elasticity, gently rubbed with the hand will emit a slight rustling sound, easy to deformation and tearing.
PET: hard texture, stiff, with high strength and toughness, not easy to be finger pressure marks.
EVA: very soft, good elasticity, feel smooth by hand, similar to the feel of rubber.
Stickiness
Plastic bags made of PE are usually not sticky; while EVA may be slightly sticky in some cases, especially in high temperature environments.
Burning Identification
PE: the flame is blue when burning, the upper end is yellow, there is the odor of burning paraffin, it is dripping after burning, and it is wax-like solid after cooling.
PP: the flame is bright when burning, there is a small amount of black smoke, there is an odor similar to petroleum after burning, the burning material will be melting and dripping, after cooling is a hard lump.
PET: yellow flame when burning, black smoke, aromatic odor, burning will leave black residue, hard texture.
EVA: burning flame is yellow, paraffin odor, the combustion process will produce molten droplets, and the burning speed is faster.
Combustion identification method has a certain degree of danger, the operation of the need to pay attention to safety, and may cause pollution to the environment, generally not recommended for use in the home environment, more suitable for professional laboratory conditions.