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The characteristics of different layers of plastic packaging bags

The characteristics of different layers of plastic packaging bags

  • Categories:Industry Trends
  • Author:
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  • Time of issue:2021-01-19 15:51
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(Summary description)Among the applied materials of plastic packaging bags, there are often three-layer, five-layer, seven-layer, and nine-layer composite films. What is the difference between different layers of composite film? 5 layer and 3 layer comparison

The characteristics of different layers of plastic packaging bags

(Summary description)Among the applied materials of plastic packaging bags, there are often three-layer, five-layer, seven-layer, and nine-layer composite films. What is the difference between different layers of composite film?

5 layer and 3 layer comparison

  • Categories:Industry Trends
  • Author:
  • Origin:
  • Time of issue:2021-01-19 15:51
  • Views:
Information
Among the applied materials of plastic packaging bags, there are often three-layer, five-layer, seven-layer, and nine-layer composite films. What is the difference between different layers of composite film?
 
5 layer and 3 layer comparison
 
The barrier layer in the 5-layer composite film is usually in the core, which insulates it from the moisture in the atmosphere. Because the barrier layer is in the core, other materials can be used to greatly enhance the barrier performance. Nylon can be used in the core layer, so that the 5-layer structure with a PE surface layer can handle more materials like PE film and improve the process capability. Moreover, the processor can use pigments in the outer layer without affecting the bonding layer or barrier layer.
 
Three-layer composite films, especially those using nylon, have a tendency to curl because of the different physical properties in the asymmetric structure. For 5-layer structures, it is more common to use symmetrical or nearly symmetrical structures to reduce curling. Curl in a 3-layer structure can only be controlled by using nylon copolymers. In a 5-layer structure, the processor can use nylon 6 to obtain a nylon layer that is almost half the thickness of the 3-layer film. This saves raw material costs while providing the same barrier performance and improved processing performance.
 
7-layer and 5-layer comparison
 
For high-barrier films, EVOH is often used as a barrier layer to replace nylon. Although EVOH has excellent oxygen barrier properties when dry, it deteriorates rapidly when wet. Therefore, it is common to compress EVOH into a 5-layer structure between two PE layers to prevent moisture. In the 7-layer EVOH composite film structure, EVOH can be compressed into two adjacent PE layers, and then protected by the outer layer of PE. This greatly improves the overall oxygen barrier and makes the 7-layer structure less susceptible to moisture.
 
Shattering or tearing can also be a problem for 5-layer structures. Moving to a 7-layer structure will cause the harder barrier layer to be torn apart by the connecting thin layer into the same two layers. This maintains the barrier properties, while making the package more resistant to breakage or tearing. Moreover, the 7-layer structure allows the processor to tear the outer layer to reduce raw material costs. More expensive polymers can be used as the thin surface layer, and cheaper polymers can replace most of the previous surface layers.
 
9th floor compared with 7th floor
 
Generally, the barrier part of the high barrier composite film occupies 5 layers in the structure. Because of advances in polymers and processing technology, the percentage of the overall thickness of this part in the entire structure is constantly decreasing, but the same barrier properties are maintained.
 
However, it is still necessary to maintain the film thickness of the overall composite film. The development from 7 to 9 layers enables the processor to obtain the best mechanical, appearance and cost performance. For high-barrier films, the additional versatility provided by the 7-layer or 9-layer extrusion line may be very impressive. The increased cost of purchasing a 7-layer or 9-layer extrusion line compared with a 5-layer production line can have a payback period of less than one year.

More information

Due to the moisture absorption of nylon film and the series of adverse consequences caused by moisture absorption, there are certain requirements for the environment of paper-plastic packaging manufacturers. Generally, it should be stored at about 23°C, ±3°C, and the dry humidity difference is ideal within the range of 60%RH±5%RH. The nylon membrane cannot be placed directly on the floor or in the open air to avoid moisture absorption. The difference between dry and wet in the production environment generally does not exceed 75% RH. If it reaches 80% RH, production should be stopped (especially compound production) to avoid bad causes. If the task must be put into production, exhaust fans and dehumidifiers can be added to the production site to enhance indoor air circulation and reduce the humidity of the production environment to below 70%RH for reproduction. In short, when the humidity exceeds 70%RH, you must use it with caution. When the temperature is low or the humidity is too high, you must turn on the preheating equipment of the printing and laminating machine, first preheat the nylon film, and dry it on the surface of the nylon film. In order to facilitate the smooth progress of printing and composite production; at the turn of winter and spring, due to large temperature changes, when using mixed solvents, pay attention to effective adjustments with changes in temperature to prevent solvents from evaporating too fast or residual solvents. More quality accidents.
In addition to containing and sealing the product, a packaging bag is more important to isolate the product from the outside world to protect the product. In addition, the molecular interaction between the packaging material itself and the product causes the product to deteriorate, which has become a problem that the packaging bag manufacturer needs to solve. This article focuses on explaining how we solved this problem. Packaging bag manufacturers generally use PE material film in direct contact with the product. So, what is a PE material film?
Plastic packaging bag manufacturers tell us that we need to pay more attention to the later stage of manufacturing products, because the product will over-harden if you are not careful. This phenomenon occurs because the proportion of ingredients has not been properly handled. Today we will understand how to prevent it. The appearance of hardening.
Will the vacuum food packaging bag wrinkle? How to solve it? 1. Replace the qualified film. 2. Adjust the position of the film so that it does not deflect during the conveying process. 3. Adjust the amount of glue applied and apply glue evenly. 4. Adjust the process parameters to make the adhesive fully dry and reduce the residual amount of solvent. 5. The composite film should be fully cooled before rewinding. 6. Adjust compound pressure. 7. Adjust the tension of unwinding and rewinding to match the tension of each part. 8. Adjust the parallelism of each guide roller. 9. Clean the surface of each guide roller and replace the damaged guide roller to ensure that the surface of the guide roller is flat, smooth and clean.
Among the applied materials of plastic packaging bags, there are often three-layer, five-layer, seven-layer, and nine-layer composite films. What is the difference between different layers of composite film? 5 layer and 3 layer comparison
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