What is the analytical method of stretched film? Shenzhen pe packaging film

Stretched films are usually made by blow molding and tape casting. Blow-molded polyethylene stretch film is formed by blow-molding PE particles with a blow molding machine, which has low cost and is therefore the most widely used. Let's take a look together.

1, with the naked eye

The surface gloss of qualified new stretched film is naturally soft, clear and transparent, without impurities and black spots. The "fake" stretched film is characterized by low transparency, uneven film layer and low transparency due to the use of plasticizer and whitening agent, which is easy to distinguish from the appearance.

Step 2 pull by hand

Stretched films generally have strong tensile properties, and the stretching rate is generally between 300% and 700%. You can stretch it at will when you buy it, and it is very convenient to test it according to the instructions. In addition, the stretched film is self-adhesive and will stick to the hand after continuous stretching. However, the "fake" stretched film is uneven in tension, easy to break and poor in self-adhesion, and can not be well bonded even when mixed together.

burn

Experienced customers will have a fire to judge the material situation. Generally speaking, the pure PE stretched film is light yellow in the flame and can burn quickly, with almost no residual impurities and the smell of burning candles.

Due to the confusion of raw materials, the flame color of the "fake" stretched film is yellow-green, with pungent smell and sometimes black smoke.

Soak in water

Cut off a small stretch film and put it in water to soak it fully. A good stretched film will float on the water, and a "fake" stretched film will float or sink. This is because the raw material density of stretched films is low (about 0.8), while the density of "fake" stretched films is generally high. Ming' an packaging