What are the commonly used high temperature cooking bags

Because of the high quality requirements of high-temperature cooking bags, the use of solvents must also be particularly careful. First of all, high-temperature cooking bags used in the adhesive and ink itself hope to use high-quality, high-purity non-toxic, tasteless, odorless, non-residual solvents, should not contain benzene, toluene, xylene, cyclohexanone, or other high-boiling point solvents. In recent years, the demand for high-temperature-resistant steaming bags has risen and attracted attention. For the temperature grading of cooking bags, the more consistent international practice is to classify them into 3 categories: (1) 121℃ high-temperature cooking bags. It is sufficient for most of the packaged food products to keep the sterilization treatment at 121℃ for 40 minutes, but for some special contents such as beef, it is necessary to keep the sterilization treatment at 121℃ for 60 minutes. Of course, for aquatic products, soybean products, then as long as the sterilization process under 121 ℃ to maintain 10 to 20 minutes on the line. (2) 135 ℃ high-temperature cooking bag. It is enough to keep the sterilization treatment under 135℃ for maximum 20 minutes. (3) 145 ℃ ultra-high temperature short time cooking bag. This is the highest level of cooking bag, with its packaging of food, at 145 ℃ in general as long as to maintain 2-3 minutes, up to 4 ~ 5 minutes of sterilization treatment, can be the most heat-resistant harmful strains of bacteria, such as Bacillus botulinum to kill fire clean. Manufacture of high-temperature cooking bag materials 1. base material high-temperature cooking bag structure has two, three, four or more layers. Among them, two-layer cooking bag is transparent plastic / plastic type, such as pet / cpp or opa / cpp; three-layer cooking bag has a transparent plastic / plastic type, such as pet / opa / cpp, there are opaque type containing aluminum foil, such as pet / ai / cpp, opa / ai / cpp; four-layer cooking bag is containing aluminum foil, opaque pet / ai / opa / cpp, the structure is Anti-puncture, reinforced, large-capacity bags, opa should be placed between ai, and cpp is more reasonable. More layers of the inner layer of cooking bags do not use pure cpp film, but with multi-layer **** extrusion film, such as pa / evoh / pp that **** extrusion film, pa / pva / pp **** extrusion film, and then with the pet or aluminum foil constitutes a more multi-layer number of composite film, but its number is not much. From a functional point of view, containing aluminum foil four-layer structure pet / ai / opa / cpp cooking bag can fully meet all the requirements of cooking food. In addition, in the cooking bag can be applied to the material, there are high barrier pvdc, high oxygen barrier pva, high heat resistance and high barrier pen, special aromatic nylon mxd6 and so on. 2. Adhesive At present, most of the composite film used in high temperature cooking bag is made through the composite method. Dry composite adhesive used in aromatic polyurethane adhesive, aliphatic polyurethane adhesive thousand mouth maleic anhydride modified polypropylene suspension adhesive three varieties. Cooking bag production is the earliest use of aromatic polyurethane adhesive, but because the adhesive residual monomer in the high-temperature cooking may produce cracked "debris", endangering the health of the consumer. Therefore, since the early 1980s, the United States fda raised objections, many companies will use a more secure call rely on the maleic anhydride modified polypropylene suspension adhesive and aliphatic polyurethane adhesive manufacturing high temperature cooking bag. High-temperature cooking bag with the adhesive must have a very good adhesive fastness, high temperature media resistance and heat resistance. Performance rape of high-temperature cooking bag with adhesive, after high-temperature cooking, peeling force is reduced little or no reduction, or even rise. 3. ink Ordinary ink is not heat-resistant, after cooking to leave the layer, some colors will change or fade. Good high-temperature cooking ink should be a two-component reactive polyurethane as the linking material ink, the advantages of printing fastness is good, in pet or opa film can be satisfactory results, after crosslinking and curing, the ink layer can be resistant to high temperatures, and the adhesive can be formed between the very strong bonding force. However, the remaining ink will gradually crosslinking curing and loss of printability, so, often resulting in waste, high cost, which requires the ink is best to use as much as the number of matching, do not match too much at once. 4. 4. solvent As a result of the high quality requirements of high-temperature cooking bag, the use of solvents must also be particularly careful. First of all, high-temperature cooking bag using the adhesive and ink itself want to use high-quality, high-purity non-toxic, tasteless, odorless, non-residual solvents, should not contain benzene, toluene, xylene, cyclohexanone, or other high-boiling point solvents. Secondly, the diluting solvent used in mixing glue and ink should also have strict standards for its water content. High-temperature cooking bag manufacturing process At present, the vast majority of domestic cooking bags are manufactured using the dry composite method, there are some solvent-free composite method or *** extrusion composite method of manufacturing, here only talk about dry composite manufacturing process. Selection of materials Selection of materials should be based on the end use of cooking bags to determine, including the nature of the packaging, weight, cooking sterilization temperature and time, shelf life of food and so on. Because of the different end uses, the quality of the cooking bag requirements are different, the combination of material structure, adhesive and ink quality requirements are different, and the cost is not the same. 2. Determine the process parameters In the specific operation, the operator should strictly follow the process parameters of the process sheet, including the number of lines of the coating roller and the depth of the net cavity, the amount of glue, the concentration of glue, the drying channel of the heating section of the discretionary temperature, the amount of air blower and the size of the exhaust volume, the start-up speed, as well as unwind tension, drying channel tension, the control of the winding tension, composite surface temperature of the steel rollers and the pressure of the composite, and so on. Among them, the amount of glue (generally 4 ~ 5g / m2) and the amount of residual solvent (the national standard is less than 10g / m2 enterprise internal control is best less than 3mg / m2 is the key to the inherent quality of the cooking bag, must be taken seriously. 3. Composite composite operation; some adhesive suppliers require the first two layers (pet / ai or opa / ai), after the composite, it should first be put into the 50 ~ 55 ℃ ripening room ripening 4 ~ 12 hours, and then the third layer (pet / ai / cpp or pet / ai / opa) composite. But there are also many adhesives can be directly two, three or even four layers of material all composite and then ripening. 4. ripening ripening is generally required at 50 ~ 55 ℃ to maintain more than 48 hours, preferably 72 hours, but also some adhesive requirements placed 5-7 days. But also maintain the ripening of indoor ventilation flow, maintain the same temperature at all points in the room, the indoor air should also be appropriate replacement, the ripening of residual solvents released when discharged to the outdoors, and then replenish the dry; fight for refreshing the fresh air, which is conducive to reducing the amount of residual solvents composite film and odor. 5. detection of bag making Composite film after ripening, to first test the composite fastness between the layers and the amount of residual solvents, to meet the requirements before you can take out the bag making. Use of composite film materials, most of the cooking bag using three-sided seal made of flat bags or stand-up pouches, rarely made of back-seal bags. Different structures, different combinations, different layers of composite film, its heat sealing strength is different, between 45-80n/15mm. Steamer bags with cpp film or hdpe film as the heat sealing layer, the melting point is higher than ldpb. So the temperature of the heat sealing knife is also much higher, most of the 180-230 ℃ in the heat sealing bag, for the composite layer less, the smaller the thickness of the composite film, the lower the temperature of the heat sealing knife; for the more layers, the thickness of the composite film or containing aluminum foil, the higher the temperature of the heat sealing knife at the discretion of the temperature. In addition, some bag-making machine on the knife and the knife can be heated, some bag-making machine is only on the knife can be heated, for the composite layers, the thickness of the film, the upper and lower knife can be heated discretionary way more ideal. Particularly need to remind is that the hot knife pressure down, never make the bag inside pressure, outside pressure is small, and it is best to adjust to the inside of the bag pressure is slightly less than the outside pressure. This will not make the two layers of the inner membrane pressure fusion, the film's original state is damaged, sealing strength is guaranteed.