Features of Shrink Film
Shrink packaging is a packaging technology method that wraps items (or inner packages) with shrink film, and then heats the shrink film appropriately to make the shrink film
shrink and stick to the items (or inner packages).
① Shrink packaging can pack special-shaped products that are difficult to pack in general methods, such as vegetables, fruits, fish, etc.
②The film itself has cushioning and toughness, which can prevent the product from being damaged due to vibration and impact during transportation.
③The shrink film
of shrink packaging is generally transparent. After heat shrinking, it is close to the product and can display the appearance of the product. Due to the relatively uniform shrinkage. And the material has a certain toughness, and the corners are not easy to tear.
④ It has good sealing, moisture-proof, anti-fouling and anti-rust functions, which is convenient for stacking in the open air and saves storage area.
⑤Scattered and various products can be packaged together conveniently, and sometimes the packing box can be saved by means of shallow trays.
⑥The packaging process and equipment are relatively simple, versatile, easy to realize mechanization, save manpower and packaging costs, and can partially replace corrugated boxes and wooden boxes.
⑦ The on-site shrink packaging method can be used to package bulky products, such as rowing boats and cars, etc., and the process and equipment are very simple.
⑧ It can prolong the fresh-keeping period of food and facilitate storage.
Shrink Film Material
The shrink film
is a polyethylene film that has been specially stretched and cooled. Since the shrink film produces residual shrinkage stress during directional stretching, this stress will be eliminated after being subjected to a certain amount of heat, so that it will undergo sharp changes in both the transverse and longitudinal directions. Shrinkage, while increasing the thickness of the shrink film, the shrinkage rate is usually 30% to 70%, the shrinkage force reaches the maximum in the cooling stage, and can be maintained for a long time.
Degradable shrink film
not only has the functions and characteristics of traditional plastics, but also can be split and degraded in the natural environment by the action of microorganisms in soil and water or by the action of ultraviolet rays in sunlight after reaching the end of its service life, and finally re-enters in a reduced form. In the ecological environment, return to nature. Domestically developed varieties have covered photodegradation, photobiodegradation, photooxidative biodegradation, high starch content biodegradation, high calcium carbonate filled photooxygen degradation, and full biodegradation. The most commonly used of these are edible films and water-soluble films.
Photo/biodegradable polyethylene can adjust the photodegradation speed of the film through the type and amount of photosensitizer. The photosensitization effect of iron stearate and cerium stearate is similar, both are better than iron diethyldithiocarbamate; when the mass fraction of photosensitizer is 0.2% to 0.3%, the light/biodegradable film photodegrades The performance is better. As the degree of photodegradation of the film increases, the carbonyl index and the crystallinity of polyethylene in the film increase, while the melting point and relative molecular weight decrease. Its photodegradation products contain low molecular weight alkanes, ketones, aldehydes, esters, monocarboxylic acids and dicarboxylic acids, etc.