"Covering cartons" use nanotechnology

Processes tend to be simpler and single functions stand out

Fruits and vegetables and other fresh foods require a strong preservation function in the outer box. Nanotechnology is the most popular technology today. How are these two combined?

The application of nanotechnology in the manufacture of corrugated boxes can greatly enhance the functional advantages of the carton and enhance the preservation of the carton.

The key to the production of fresh-keeping corrugated cartons is the design and innovation of nano-modification of traditional corrugated cardboard and the adaptation of traditional corrugated box structures to the preservation requirements. Fresh-keeping corrugated carton is a new technology product. It is a product of cross-conjugation between modern science and technology and packaging engineering, and reflects the development direction of modern packaging technology.

1. Mixing nanocrystals with larger molecules (such as polymer molecules) can make a dramatic change in material properties. Nanoparticles can act as nucleation sites to orient polymer molecules around it. The incorporation of nanoclay into nylon 6 can improve the mechanical and rheological properties of the material. Therefore, adding nanocrystalline grains during the polymerization process can form a barrier in the cured nylon that can block the movement of gas molecules. Compared with ordinary nylon 6, the nanocomposites have a 6-fold increase in the resistance to oxygen and carbon dioxide permeation.

Honeywell lnetmational, New Jersey, USA, introduced a series of nylon nanocomposite products, which enhances the oxidation shielding ability and degassing ability, and can increase the bending strength of the drawing die and the bending die by 30%-50%. Performance increased by l times. Honeywell produces a product called AegisNC, which is suitable for use in cardboard boxes for packaging fruit and frozen foods to prevent the penetration of oxygen and carbon dioxide.

2. The existing fresh-keeping technology and fresh-keeping technology applied on packaging are very complicated, and the preservation effect is not good. Moreover, the cost is relatively high in the process of packaging production, storage and transportation. After adopting nano-technology, these problems will be solved.

If the packaging of fresh foods such as fruits and vegetables is to achieve the effect of fresh keeping, it is necessary to solve the problem that ethylene causes deterioration of fruits and vegetables. In the packaging, fruits and vegetables will accelerate the decay rate after the ethylene released by fruits and vegetables reaches a certain concentration. To solve this problem, ethylene absorbers should be added to the fresh-keeping packaging to reduce the ethylene content in the packaging and improve the preservation effect. However, the effect of the currently used ethylene absorbent is not satisfactory. Application of nano-technology can solve this problem. Nano-sized Ag powder has a catalytic effect on the oxidation of ethylene. Adding nano-Ag powder to the fresh-keeping packaging material can accelerate the release of ethylene from the oxidized fruits and vegetables, thereby achieving a good preservation effect.

3. Fresh-keeping corrugated cardboard and fresh-keeping corrugated carton--

(1) Preservative corrugated cardboard

The method of keeping fruits and vegetables fresh is to reduce water loss, inhibit biological respiration and bacterial growth, and remove the ethylene gas that causes them to age and mature. Preservation of corrugated cardboard is based on these aspects.

1Composite fresh-keeping corrugated cardboard: The aluminum-plating cling film layer is compounded on the inner surface of the corrugated cardboard. This composite film has the function of absorbing ethylene gas, which can prevent moisture from evaporating and has the function of reflecting radiation, and can prevent inside of the box. Temperature rise, play a role in preservation.

2 Mixed fresh-keeping corrugated paperboard: In the manufacturing process of corrugated paperboard inner paper, nanoscale porous ethylene gas absorption powder can be added to prevent ripening; special ceramic powders capable of emitting 6-par.-141xm-wavelength infrared light can also be coated on the base paper. . This kind of powder can emit infrared rays at room temperature, which can not only activate the relevant molecules in the fruit, increase the ability to resist microbial erosion, but also activate the enzyme and increase the sweetness of the fruit. The cartons manufactured by this method are particularly suitable for packaging peaches, grapes, bayberry and other products, and have excellent preservation effect.

(2) Fresh-keeping corrugated carton

1 Antibacterial Preservative Corrugated Cardboard and Carton: In order to preserve freshness, fruit and vegetable products, it is very important to control the environmental conditions such as temperature, humidity, and air of packaging containers. For example, maintaining a moderately low temperature can inhibit the respiration of the contents. Maintaining a proper temperature can reduce the evaporation of water and eliminate the ethylene gas naturally emitted from the contents, thereby suppressing the aging phenomenon.

Another problem encountered in the preservation of fresh fruits and vegetables is that the contamination of pathogenic microorganisms causes the fruits and vegetables to wither and rot. Therefore, what measures are taken to curb the proliferation of microorganisms to achieve antibacterial preservation is a problem that cartons have to face. The solution is to apply a layer of nano-antibacterial antiseptic on the surface of the liner of the antibacterial fresh-keeping corrugated cardboard. This anti-corrosion method has no effect on food hygiene.

2 Silica mixed liners Corrugated paperboard and carton: The corrugated paperboard has good preservation performance. The processing method of the paperboard is exactly the same as the ordinary corrugated paperboard, and there is no need to sandwich any material between the liner paper and the corrugated cardboard. It can play a role in freshness because the backing of the paperboard contains nanopowders that can absorb ethylene gas. Nanopowder is a porous powder made mainly of silica and made of silica. Because the silica silica has better adsorption capacity for the ethylene gas than activated carbon, rare earth zirconium, and zeolite, the use of the paper added with the nano silica silica powder as the liner of the corrugated cardboard has better preservation effect.
(Source: Packaging Newsletter)