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Common problems of high temperature retort packaging bags

High-temperature retort bags are widely used in modern packaging. The packaging process of manufacturers to produce retort food is bagging, vacuuming, heat sealing, inspection, retort heating sterilization, drying and cooling, and packaging. Cooking and heating sterilization is the core process of the whole process. However, the molecular chain movement of the packaging bag made of polymer material – plastic is intensified after being heated, and the physical properties of the material are prone to thermal decay, which causes problems. Let YLTpacking plastic bags take you today to learn how to prevent some common problems of high temperature cooking bags. High temperature retort food is to heat and sterilize food together with packaging materials after packaging. In order to achieve high physical properties and good barrier properties, retort-resistant packaging is composed of a variety of substrates. Common materials include PA, PET, AL and CPP, and common structures include two-layer composite films (such as BOPA/CPP, PET, etc.). /CPP), three-layer composite film (such as PA/AL/CPP, PET/PA/CPP) and four-layer composite film (such as PET/PA/AL/C PP). High-quality high-temperature cooking food packaging materials should have the following conditions: ①Good mechanical properties, high strength, softness, and can meet the needs of various packaging machinery, bag making machines, and heat sealing machines; ②Good heat resistance, at 121 ℃ Cooking for 40min at the temperature, the packaging film and bag are dimensionally stable, not deformed, not delaminated, and not cracked at the heat seal; ③It has high barrier properties, and the oxygen transmission rate is lower than 30cm3/m2.24h.23℃, RH50%, The water vapor transmission rate is lower than 5g/m2.24h.38℃.atm, RH90%; ④Excellent food hygiene, does not contain harmful substances, and will not produce harmful substances after being cooked at high temperature. Food contact, stable chemical properties, will not chemically react with various ingredients in food to generate substances harmful to human body; ⑤Good product display, highly transparent, and the surface can be printed in color. However, there will be many problems in actual production. The most common quality problems are wrinkling, broken bags, air leakage and peculiar smell after cooking: ① There are generally three manifestations of wrinkling in packaging bags, that is, the appearance of packaging substrate. Horizontal or vertical or irregular wrinkles; each composite layer is wrinkled and has poor flatness; the packaging substrate shrinks, and the shrunk composite layer is separated from other composite layers in stripes. The broken bag is divided into two types: direct bursting and wrinkling and then bursting. ② Delamination refers to the phenomenon that the composite layers of packaging materials are separated from each other. Slight delamination is manifested as striped bulges in the stressed part of the package, and the peel strength is reduced, and it can even be torn by hand. If delamination occurs, the synergistic strengthening effect of the physical properties between the composite layers of the packaging material will disappear, the physical properties and barrier properties will be greatly reduced, and the shelf life requirements will not be met, which will often cause great losses to the enterprise. ③ The incubation period of slight air leakage is long, and it is not easy to detect during cooking. During the circulation and storage of the product, the vacuum degree of the product is reduced, and it is only found when there is obvious air in the packaging. Therefore, this quality problem often involves more products and has a greater impact. The occurrence of air leakage is closely related to the poor heat sealing and poor puncture resistance of the cooking bag. ④The peculiar smell of food after cooking is also a frequent quality problem. The peculiar smell after cooking is related to excessive solvent residues in packaging materials or improper material selection. If PE film is used as the inner sealing layer of the high temperature cooking bag above 120°C, the PE film is prone to odor at high temperature. Therefore, it is appropriate to choose CPP material for the inner layer of the high temperature cooking bag. The above are some of the problems encountered in the application of high temperature retort bags. This is also the experience of YLTpacking plastic bags after 18 years of continuous practice. It is because of such rich experience that many well-known brands at home and abroad come to YLTpacking. YLTpacking will continue to strengthen the technical strength of the company and make more good packaging bags for more users.

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