What are the packaging materials for cold chain logistics?

What are the packaging materials for cold chain logistics?

In recent years, the development of e-commerce has changed the way of Chinese people's consumption behavior, and the categories of online network shopping are becoming more and more rich and diversified, which can include frozen food, milk, fruits, fresh food and medicines, etc., which are required to be delivered by enterprises at low temperature. Under this changing trend, the cold chain logistics industry has seen explosive development.

According to different classification standards, cold chain logistics can be divided into various types, such as only from the operation mode division mainly includes two modes.

The first mode is to use "foam box + cold bag", generally known as "packaging cold chain". It is characterized by the use of packaging itself to create a small environment suitable for short-term storage of fresh products. The advantage of this approach is that the packaged products can be distributed through the room temperature logistics system, the total logistics cost is low, basically adopted by the traditional fresh food e-commerce; the disadvantage is that the packaging is a one-time consumable, not environmentally friendly.

The second mode is to utilize a real cold chain logistics system, i.e., the products are in a low-temperature environment from the cold storage at the origin all the way to the hands of the final customers to ensure the cold chain. This model realizes temperature control throughout the cold chain and is generally referred to as the "environmentally friendly cold chain". Its advantage is to use the cold chain environment to maintain temperature control, reduce unnecessary packaging, very environmentally friendly; the disadvantage is that the cold chain logistics system requirements are very high, it is difficult to use the ordinary logistics system to run, the overall operating costs are high.

In 2019, the total demand for cold chain logistics in China reached 261 million tons, of which the demand for food cold chain logistics reached 235 million tons, and the industry is still maintaining high growth in 2020 and the first half of 2021. However, the great development of cold chain logistics also brings unavoidable problems - China will produce nearly 300 million foam boxes and 1 billion ice points and other cold chain consumables every year.

Greening of packaging materials

In order to extend the use of thermal insulation work time, cold chain logistics packaging design materials are mainly through the selection of good insulation materials, such as foam for plastic (expandable polystyrene as well as foam engineering plastics), pearl cotton compound aluminum foil, corrugated paper and so on.

In the green trend, many companies are trying to replace polystyrene foam with new biodegradable materials or recycling other biodegradable incubators instead of disposable foam incubators. For example, some companies are already experimenting with incubators made from biodegradable polylactic acid biodegradable plastic and starch-based biodegradable packaging materials. Some companies are promoting green packaging, applying freshness preservation technology, and using EPP (Expanded Polypropylene Plastic) recycled thermostats and refrigerants to achieve temperature control.

The ice bag in the thermostat box is a kind of cold storage device that encapsulates the cold storage agent in a plastic bag, which is used with the thermostat box to realize the low-temperature environment in the process of cold-chain logistics and transportation. The working principle of ice bag is to absorb cold energy from refrigerator, cold storage and other equipment and store it. After a period of time, the ice bag will be completely frozen into solid state. When transporting cryogenic products, ice packs can be placed around and over cryogenic items that have been placed in an incubator. As long as a certain number of ice packs are placed to seal the incubator, the low temperature inside the incubator can be maintained for a long time.

There are two main types of insulated ice packs: one containing dry ice, which is more obviously harmful to the environment because dry ice is solid carbon dioxide that vaporizes directly into air; and the other liquid, which is a mixture of water, preservatives, and highly absorbent resins.

A new material, bio-ice, has been developed as a refrigeration material for ice packs. Bio-ice is a biological product that has passed ISO9002 international quality certification. It has the advantages of safety and non-toxicity, good heat preservation, easy to use, low cost, high safety and reusable. Compared with ordinary ice of the same volume, the freezing time is extended up to 6 times and the cold storage capacity is sufficient. The emergence of bio-ice is a revolutionary change for low-temperature transportation in remote areas.

From the perspective of food business safety management, the ingredients in liquid fresh ice packs are generally nationally safe. In spite of us so, because the vast majority of fresh ice bags of the outer packaging is ordinary plastic bags, not biodegradable plastic bags, if one does not get a reasonable way of recycling and disposal, the pollution of the environment can still exist.

Currently on the market frozen food packaging bags can be divided into single-layer bags, composite bags and multi-layer co-extruded bags. Among them, single-layer frozen food packaging bags, that is, pure PE bags, barrier effect is poor, mostly used for fruit and vegetable packaging. The multi-layer co-extruded frozen food packaging bags through different functions of PA, PE, PP, PET, EVOH and other raw materials melt extrusion molding, and ultimately blow molding, cooling composite, in the packaging performance of non-polluting, high barrier, high strength, high and low temperature resistance and other excellent characteristics.

Based on a variety of factors, composite flexible plastics are widely used in three types of frozen food packaging bags, the material structure of such frozen food packaging bags have a variety of combinations: one is PET/PE.

One is PET/PE. This material structure is more common in frozen food product packaging, moisture resistance, cold resistance, low temperature heat sealing performance is good, the production cost is also relatively low;.

The second is BOPP/PE and BOPP/CPP. These two frozen food packaging bags have excellent moisture resistance and cold resistance, high low temperature heat sealing tensile strength, and good economy. It is worth mentioning that the BOPP/PE material has a better feel than PET/PE, which is conducive to product marketing.

Third, PET/VMPET/CPE, BOPP/VMPET/CPE. three-layer network structure of the bag than a single-layer, double-layer society can be more solid security and stability, high barrier performance, coupled with the existence of aluminum-plated layer of the problem makes in the printing performance also has a more obvious advantages, but compared to the different materials mentioned above in general, the low-temperature heat-sealable performance is slightly worse, the cost is higher. Higher cost;

Fourth, PA/PE, PET/PA/Lldpe, PET/PA/AL/PE, PA/PE. the structure of these four materials is more resistant to freezing, impact, while the PA layer ensures good puncture resistance, the disadvantage is that the production cost is high, generally used for angular or heavy food packaging.

Recycling of cold chain logistics packaging

More and more biodegradable and environmentally friendly materials are being used in cold chain logistics express packaging, but they also face the problem of high cost. If it is used only once, it is neither environmentally friendly nor sustainable from a commercial point of view. Therefore, recycling cold chain logistics packaging has become a must for future logistics development.

The development of green logistics is related to the social responsibility and environmental awareness of enterprises, cold chain deliveryand is of great significance to the construction of a resource-saving and environment-friendly society. In order to comply with the general trend of development, many businessmen are actively promoting the green development of cold chain logistics packaging from different levels, using different technologies and modes, and the future prospects are worth looking forward to.

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