How to choose the raw materials for making plastic packaging bags?
There are many kinds of articles packed in plastic bags with different requirements. There are many kinds of plastic films that make up plastic packaging bags, with different properties. This requires us to correctly select thin films and comprehensively consider various situations. We can usually consider from the following aspects:
Strength In order to effectively protect commodities, the mechanical strength of packaging materials should be the first consideration. We should consider the shape and weight of commodities, the climatic conditions of circulation and the mode of transportation. Generally speaking, films with high mechanical strength include aluminum foil, polyester, nylon, biaxially oriented polypropylene and other films.
2. Air tightness
Good air tightness can effectively block the exchange of gas inside and outside the packaging container, which is necessary for most products. Films with good air tightness include aluminum foil, aluminized film, polyester, nylon, polyvinyl alcohol, polyvinylidene chloride and other films. However, for other products, such as fresh fruits and vegetables, in order to maintain their freshness, films with poor air tightness, such as polyethylene and polypropylene films, are required.
3. Moisture resistance
Good moisture resistance is an effective way to protect commodities. The moisture resistance of general plastic films increases with the increase of thickness. Films with good moisture resistance include aluminum foil, aluminized film, polyethylene, polypropylene and other films.
4. heat sealability
The film has good heat sealing performance, is easy to form a seal, can better protect commodities, and simplifies mechanical operation. Plastic films with good heat sealability include polyethylene, polypropylene and other films.
5. Heat resistance
For products that need cooking and sterilization, such as some foods and medical appliances, the film must be resistant to high temperature. Films with good heat resistance include aluminum foil, nylon, polyester, high density polyethylene and other films.
6. Cold tolerance
Some films become brittle with the decrease of temperature, which will greatly limit their use. Therefore, attention must be paid to the ambient temperature when selecting. Films with good cold resistance include nylon, polyester, polyethylene and other films.
Film with good transparency makes the contents clear at a glance, which can improve the value of goods and promote sales. Films with good transparency include cellophane, polyester, nylon, biaxially oriented polypropylene and other films.
Generally, trademarks, patterns and colors should be printed on the packaging, which is crucial to increase the beauty of the goods and promote sales. Films with good printing performance include nylon, polyester, biaxially oriented polypropylene and other films.
9. Fragrance retention
Many products, such as food, medicine, cosmetics, etc. contain some special fragrance. The dispersion of this fragrance will greatly reduce the flavor of the products. Therefore, efforts should be made to keep the fragrance for a long time. Films with good fragrance retention include aluminum foil, aluminized film, polyvinyl chloride, polyvinyl alcohol, polyvinylidene chloride, etc.