Views: 103 Author: Site Editor Publish Time: 2022-02-13 Origin: Site
As a daily bag which is widely used in our kitchen supplies, the retort pouch for sale is our good assistant. Do you really know what a retort bag is? What is it good for our life? What's special about these food packaging materials? In this article, we will show you the answer!
The aluminium retort pouch is made of heat-resistant laminated plastic, which is semi-rigid or flexible packaging. Foods such as soup, pasta, rice, sauce, and packaged retort food are sealed and disinfected in these bags, whose maximum temperature is 121 ° C, so they are ideal packaging for processed and prepackaged foods.
The idea of retort pouch bags was put forward by the U.S. Army in 1950 and the research continued until 1960. It was finally invented by the U.S. Army's nadik R & D command, Reynolds Metals, and continental flexible packaging company. These companies won the food technology industry achievement award for their invention in 1978.
Because people are not willing to accept these bags, it faces a stagnation period from the beginning, but manufacturers and companies have realized that there are many benefits from using retort pouch packs for packaging over the years.
The advantages of retort bags with nozzle are mainly due to its internal structure, the firmness of metal can, and the protection of the nutritional value. Specifically, each pouch consists of four layers.
lThe first layer is propylene, which can be used as a heat sealing surface to provide strength and flexibility.
lThe second layer is nylon to prevent wear.
lThe third layer is aluminum layer, which can not only prevent light, gas, and smell, but also extend the shelf life of products.
lThe final polyester layer provides excellent strength for printing.
In order to improve the durability of the package, the materials entering the retort food bag must be approved by FDA and sterilized.
The structure of the high temperature resistant retort packing bag has two layers, three layers, four layers or more. The second layer is transparent plastic / mold, such as PET / CPP or OPA / CPP; the third layer is transparent plastic / mold, such as PET / OPA / CPP and opaque aluminum foil, such as pet / Al / CPP, OPA / Al / CPP; the fourth layer is opaque PET / Al / OPA / CPP and aluminum foil, which is a kind of puncture resistant, reinforced, and large capacity retort pouch zip bag. The main reason for more layers is that the inner layer does not use pure CPP film but uses multi-layer coextrusion film, such as PA / EVOH / PP, PA / PVA / PP coextrusion film plus pet, or aluminum foil.
From the functional point of view, the four-layer structure PET / Al / OPA / CPP bag with aluminum foil can fully meet the requirements of all cooked food. For these materials used in food-grade retort bags, it is necessary to understand their properties and functions. The thickness of the outer layer of PET (or BOPET) film is 12 μm, which has the characteristics of high melting point, high heat resistance, high mechanical strength, high rigidity, high transparency, high odor resistance, and high gas resistance. Due to the polarity of its molecular structure, its surface tension is high and slightly increased. The surface tension after corona treatment can reach 52mn/m (i.e. 52dyn / cm), so it is very conducive to printing and bonding.