The high temperature resistant retort bag has the properties of durable packaging, stable storage, antibacterial, high temperature sterilization and other properties, and is a good packaging composite material.
So, what matters should be paid attention to in its structure and material selection? Professional flexible packaging manufacturer Bowen new materials to tell you.
The structure and material selection of high temperature cooking bag:
In order to meet the performance requirements of high temperature resistant cooking bags, the outer layer of the structure is selected from polyester film with high strength, the middle layer is selected from aluminum foil with shading and air tightness, and the inner layer is selected from polypropylene film. There are three-layer structures: PET/AL/CPP, PPET/PA/CPP, and four-layer structures are PET/AL/PA/CPP. The performance characteristics of different types of films are as follows:
1. Polyester film
Polyester film has the properties of high mechanical strength, heat resistance, cold resistance, oil resistance, chemical resistance, gas barrier, etc. Its thickness is 12gm and can be used, but many domestic polyester films have slightly poor temperature resistance, and the flatness of the product is not good. If it is too stable, it will bring great difficulties to the operation and cause waste.
2. Aluminum foil
Aluminum foil has excellent gas barrier properties and moisture resistance, so it is very important to preserve the original flavor of food. It has strong protection, making the package less susceptible to bacteria and mildew; the shape is stable at high temperature and low temperature; it has good shading and strong reflection ability to heat and light. Its thickness can be used with a thickness of 7 μm, with as few pinholes as possible, and as small a pore size as possible. In addition, its flatness must be good, and the surface has no oil spots. The domestic aluminum foil generally cannot meet the requirements. Many manufacturers choose Korean and Japanese aluminum foil. product.
Nylon not only has good barrier properties, but also is odorless, tasteless, non-toxic, and particularly resistant to puncture. It has a weakness that it is not resistant to moisture, so it must be stored in a dry environment. Once it absorbs water, its various performance indicators will decline. The thickness of nylon is 15gm It is ready to use. When compounding, it is best to use double-sided treated film. If it is not a double-sided treated film, the untreated surface should be compounded with aluminum foil to ensure compound fastness.
The polypropylene film of the inner layer of the high temperature retort bag not only requires good flatness, but also has strict requirements on its tensile strength, heat sealing strength, impact strength and elongation at break. Only a few domestic products can It is used, but the effect is not as good as imported raw materials, its thickness is 60-70gm, and the surface treatment value is above 40dyn.