Three-dimensional plastic will lead the new trend of food packaging

At present, plastics play an important role in food packaging and are widely used for the packaging of food and other products. The development of plastics polymerization technology will inevitably have a major impact on the protection of food or beverages.

"Three-dimensional plastic" refers to the "incorporation" of other polymers in the conventional plastics used today to produce tiny, hollow, three-dimensional structures that facilitate the flow of other tiny particles.

"Three-dimensional plastics" will form a new concept for packaging materials. In its three-dimensional geometry, one can place active packaging materials such as oxygen scavengers, preservatives or odor absorbents. These active agents are generally present in small bags in the package at the same time as the food.
The technical principle of "three-dimensional plastic"

The key principle of “three-dimensional plastics” is that active packaging agents cannot adhere to the surface of plastics, which may cause active packaging agents to move on their own and react with the packaged foods, affecting the quality of foods; at the same time, in theory, they are attached to The amount of active agent on the plastic surface is also not likely to have a practical effect.

The "three-dimensional plastic" is to "plant" the active packaging agent into the interior of the base plastic so that a barrier is formed between the active packaging agent and the packaged product, and they are not in contact with each other. In this case, the movement of the active packaging agent will be carried out in the plastic as required to achieve controlled activity and concentration. Of course, the movement of the active packaging agent in the plastic may be a delayed state. Although sometimes this kind of delay is beneficial, in most cases, in order to maintain the quality of the product, we need to react quickly to change the environment around the product. The purpose of the new material is to achieve: the plastic with active packaging agent can immediately play its role, and then continue to play its role in a controlled mode.

By combining the material with the channel structure and the active packaging agent with the plastic as the matrix, the transport properties of the "three-dimensional plastic" can be improved. The material with the channel structure changes the characteristics of the matrix plastic so that the gas can be transported and reacted with the active packaging agent.

Three-dimensional channeled plastics can be composed of a variety of polymers in which the minor polymer cannot be fused with the main polymer and the active packaging agent is present in or attached to the secondary polymer. The channeled structure thus formed appears to open many "roads" in the plastic, allowing the gas to enter and exit the plastic under controlled conditions. The active packaging agent contained therein can adsorb water vapor, gas and odor, etc.; release flavor substances, gases, and nutrient components; or improve plastics' transmission characteristics to gases. This new type of plastic can be extruded or thermoformed into films; it can also be made into bottles or cans by injection or extrusion.

In summary, the functions of the three-dimensional system include absorption, adsorption, controlled release, and improved transport structure.

Absorption adsorption

Absorption (or adsorption) functionality must be accomplished through active packaging and absorption channels. The substances absorbed (or adsorbed) include: water vapor, oxygen, odorous substances (such as sulfur, amine or aldehyde containing oxides), carbon dioxide, and ethylene. All of these substances are related to the spoilage of the packed foods and beverages.

Controlled release function

The completion of the release function benefits from the use of the channel structure. The passageway in the plastic brings gas or steam into the plastic, which reacts with the active agent in the plastic (this is very useful for initiating release). The substances produced by the reaction enter the surrounding environment through the "path."

"Three-dimensional plastic" structure

The tiny three-dimensional pattern of two or more polymers "mixed" with each other determines the structure of the conjugate. The properties of the final product depend on the geometry of one polymer in the other polymer, being drop-shaped, cylindrical, dish-shaped, or other shapes. At the same time, its structural stability is also crucial when the bond is remelted for injection molding or extrusion. For example, re-melting may lead to a complete change in the structure of the polymer, that is, it may become a sphere from the cylinder.

Technical studies on "three-dimensional plastics" have shown that they have developed a network-like combination of a polymer (such as PE) and another polymer (such as PEO). The network structure forms a channel structure that creates a continuous path from one area of ​​the PEO polymer to another area of ​​the PEO. This combination retains the channel structure after melting and pressure forming; the active agent remains attached to the surface of the channel after melt molding.

Structure determines the type of active agent

When the channel is used for the transport of moisture, if PEO or polyoxyethylene is used, moisture diffuses into the plastic through the channel. If the desiccant particles are attached to the channel, it will absorb moisture, so that the moisture will continue to reach the dry particles along the channel to achieve controlled moisture removal.

By selecting the type of active agent, one can allow the conjugate to adsorb other gases rather than moisture. Harmful gases include, for example, aldehydes and ketone oxidizing substances produced by biochemical spoilage; ethylene produced by the respiration of fresh fruit that continues life; and carbon dioxide that is also produced by respiration. The active agent used at this time is an oxygen scavenger, which can remove the remaining oxygen and thus hinder the aerobic reactions that often occur in foods and beverages.

Obviously, the active agent has a different molecular structure and size. To use an active agent, it is necessary to have a suitable three-dimensional structure.
The structure determines the direction of delivery. When flavor substances and other volatiles are released, antimicrobial agents such as chlorine dioxide or alcohol can be released or volatilized from the active agent through channels inside the plastic and distributed to the external environment of the packaged product. Ensure that the product is free from microbial contamination. The flavor substances in the active substances can be released or volatilized through the channels to the inside of the package to increase the flavor of the product and increase the value of the product.

Obviously, in the above two cases, the transmission direction is not the same. Naturally, its structure is also not the same and cannot be reversed.

Bring Food Protection to a New Level

Experts believe that the internal connecting channel material ("three-dimensional plastic") technology is a breakthrough in the field of packaging. It enables the controllable transfer of many small molecules in polymers, thus enabling numerous absorbing and releasing active molecules to be applied. Packaging material is achieved. This technology will be widely used in medicine, agriculture, and of course, packaging in many areas such as food.

The medium for this active packaging agent application presents an example in food packaging, which is to open up the application space for active packaging agents by revealing the interaction between the packaging and the product. This technology holds a potential that can change the world's food protection from packaging.