The technology used to make micro perforated bags mainly involves adding tiny air holes to the plastic film to achieve air permeability and humidity control. This process usually uses the following microporous technologies:
1. Mechanical microporous technology (needle punching)
Process principle: micro perforated bags use mechanical needle punching to punch uniform micropores on the plastic film. The size and density of the micropores can be controlled by adjusting the frequency, angle and strength of the needle punching.
Advantages: low cost, simple operation, suitable for mass production.
Application: mostly used in food packaging bags, such as bread bags, vegetable bags, etc.
2. Laser microporous technology
Process principle: micro perforated bags use laser equipment to accurately punch holes on plastic films. The laser can accurately control the aperture, hole spacing and position, and can achieve a very uniform arrangement of micropores.
Advantages: high precision, customizable aperture and hole density; suitable for product packaging with strict requirements on air permeability.
Application: suitable for high-end fresh packaging with high air permeability requirements, such as high-end packaging of fruits and vegetables.
3. Corona microporous technology
Process principle: The surface of the plastic film is subjected to short-term high-energy treatment by corona discharge equipment to produce tiny micropores on the surface of the plastic film.
Advantages: Non-contact processing, suitable for film surface treatment; small pore size and low air permeability.
Application: Used for packaging that requires micro-permeability and high preservation effect, such as some cooked food or refrigerated product packaging.
4. Nano-microporous membrane technology
Process principle: Micro perforated bags use chemical and physical processes to form nano-scale micropores in the structure of the film during the production of plastic film.
Advantages: The pore size is extremely small, the air permeability is precise, and it is suitable for special packaging needs.
Application: High-end food packaging, medical packaging, and commodity packaging that requires special preservation function.
5. Cold-pressed microporous technology
Process principle: Micro perforated bags form micropores on the surface of the plastic film by low-temperature extrusion or embossing, usually used for thinner CPP or BOPP materials.
Advantages: Little damage to the material and relatively stable pore size control.
Application: Mainly used for refrigerated and frozen food packaging, suitable for products with low air permeability but requiring humidity adjustment.
6. Precautions for micro perforated bags
Aperture control: The aperture size of microporous bags should be determined according to the specific needs of the packaging. Food packaging mostly uses micropores with a diameter of 0.1-1mm, while products with higher requirements for freshness will use smaller apertures.
Pore density selection: The number and arrangement of micropores will also affect the air permeability of the packaging. Usually, humidity and air permeability are controlled by hole density.
These microporous technologies can ensure that the bag body maintains high transparency and flexibility while providing appropriate air permeability in the production of microporous bags. They are important process means in the fields of modern food packaging, refrigerated packaging, etc.
