Laser drilling - application solution for modified atmosphere fruit and vegetable fresh-keeping packaging

The primary task of preserving fresh fruits and vegetables is to maintain the appearance, hardness, taste and flavor of perishable fruits and vegetables. Most fresh fruits and vegetables lose their commodity value if they lose their appearance. Harvested fresh fruits and vegetables are still living organisms and will continue to undergo a series of physiological changes to further fully manifest their unique flavor and taste and make them more suitable for people's needs. This process is called the ripening stage; then, fruits and vegetables gradually lose their original color, aroma, taste and nutrients, and even soften and decompose. This is the aging stage. Trying to delay the ripening and aging process of fresh fruits and vegetables, that is, to maintain the original quality process as much as possible, is called the fresh-keeping period. Reducing waste and loss is one of the research directions of the flexible packaging industry.

Controlled atmosphere fresh-keeping packaging

Controlled atmosphere film packaging is one of the most commonly used fruit and vegetable preservation technologies at home and abroad. According to the physiological characteristics of fruits and vegetables, this technology replaces the original atmosphere in the package with a certain proportion of mixed gas (oxygen, carbon dioxide, nitrogen, etc.), and selects the appropriate film to maintain the best air permeability and moisture permeability.

However, at present, MAP in the domestic market mostly uses films made of materials such as polypropylene or polyethylene to package fruits and vegetables. The film has low air permeability and it is difficult to maintain a good breathing rate continuously; the water vapor in the package is easily saturated and condensed into water droplets, which can easily cause the growth of harmful microorganisms and accelerate the decay of fruits and vegetables.

Laser Micro-PerforationCling Film Packaging

In order to solve this problem, micro-perforation cling film packaging technology was created. This technology can customize the optimal aperture and number of holes by combining the transpiration rate and respiration rate of agricultural products.

The main punching methods currently used in the industry are: mechanical punching (such as punching, hot needle, discharge, etc.) and laser punching. Laser punching is the first laser processing technology to be commercialized and is also one of the main application areas of laser processing.

Compared with other drilling methods, laser drilling can simply meet the requirements of micro-aperture (generally, the aperture of micro-perforated cling film must be between 50 and 200 microns). Laser processing has high precision, large operating area, easy monitoring and adjustment, and no direct contact with the film body (clean and pollution-free), which is suitable for food packaging processing.

The laser process is very flexible and can be easily integrated into the packaging machine to monitor and adjust the size of the hole in real time. The spacing of the holes can be easily changed through programming to optimize the production cycle.

Laser micro-perforationAdvantages of packaging

Accurately control the size and number of holes to achieve optimal air permeability and moisture permeability;

Use physical technology to extend the storage time, and the nutritional components, color and taste of vegetables are not destroyed

Small pore size, neat edges, not easy to crack;

Anti-fog control to achieve optimal transparency under temperature changes.

Laser Micro-perforated FilmIndustry Prospects

There are many choices of lasers, but because carbon dioxide lasers have the advantages of high pulse energy and output power, low operating voltage, safe application, high optical quality, good stability, uniform discharge, and suitability for large-area work, they are very suitable for micro-perforated flexible packaging.