High-temperature cooking bag technology key point template
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In order to control the quality of high-temperature cooking products, we must pay attention to the operation of the three processes of printing, compounding and bag making. In the production process, each control project should be inspected according to requirements. This is the basic measure to verify whether the quality meets the standard. Therefore, the whole process from raw material to finished product should be strictly carried out, especially the high temperature cooking test to verify the function of the bag. careless.
Printing process
1. Before printing, the BOPA nylon membrane can be placed in a room with a temperature of 35 degrees in the curing chamber for 2 hours for preheating. The printing workshop should control the relative humidity. When the relative humidity exceeds 75%, we recommend not to print. When printing, pay attention to the gradient of drying temperature, otherwise it will affect the drying and overprinting accuracy of BOPA.
2. According to the characteristics of the printing material and the composite film structure, select the appropriate ink. For example, BOPA nylon is used as the printing layer. The pigments of individual colors may penetrate on the BOPA in the cooking state, as well as only the printing layer and heat sealing. In a two-layer retort pouch, the ink also has the potential to penetrate on the RCPP, posing a risk of contamination of the contents. Therefore, it is recommended to choose the anti-cooking ink, please choose to use the penetration-resistant ink to further reduce the risk.
3, need to use a large area of spot color and white ink to add 3% of the ink curing agent, must be based on the technical information provided by the ink manufacturer to determine the amount of addition, not too much or too little. This place should be called with a precise electronic scale. The remaining ink recovered in the ink tray, no matter how long it is stored, can no longer be used for printing high temperature cooking products. It is recommended to be used on other products as soon as possible after use. (Only if there are not enough orders for high temperature cooking products.)
4. Minimize the residual amount of solvent in the printing material, and the adhesion fastness of the ink is good. It is necessary to select standard production process parameters, such as oven temperature, air volume and machine speed. For large-area inks with ink curing agent, the oven The temperature is 10~15 °C higher than other inks.
5. The printed BOPA film must be wrapped with a composite film of AL foil or composite aluminized film to prevent moisture shrinkage and performance changes.
6. The printing material with the ink curing agent added should be re-rolled once, and the storage time should not exceed three days, that is, at least the printing layer should be composited within three days.
Compound process
1. The use of high temperature cooking glue must be in accordance with the manufacturer's instructions, such as the ratio, the temperature and time of curing, etc., the purity of the ethyl acetate solvent used for dilution should reach 99% or more.
2. The thickness of each layer of material should be uniform, and the thickness deviation should not exceed 7%. In addition to the mechanical properties of the product, the surface of the AL foil should be dry and the cleanliness must reach the A-class standard, that is, distilled water. When inspecting, all should be infiltrated, and the number of pinholes should be as small as possible. The storage time before use should not exceed three months. In order to enhance the composite fastness, the BOPA compounded in the middle should be double-sided corona, and the corona value is not less than 50 dynes.
3. The coating of glue should be uniform. According to the characteristics of different manufacturers and different types of glue, the dry basis should generally be 3.5~4.8g/m2. When the minimum coating amount is reached, the left, middle and right positions are coated. The cloth deviation should not exceed 0.3 g/m2 as a reference. The curing agent should be added as required. If the ambient humidity of the dry workshop exceeds 75%, the amount of curing agent should be increased appropriately, which is generally increased by 5%~10% on the original basis. If the printed pattern of the product has more yellow In the light-colored area such as white, the coating amount during production is increased by about 0.3 g/m2 than the dark pattern design to prevent obvious spots after cooking.
4. Determine the appropriate machine processing parameters, especially the oven temperature of the three sections is 5~10 °C higher than that of the ordinary products, the composite heating roller temperature is 70~80 °C, and the composite pressure is 0.1~0.2MPa higher than the common products of the same specification. According to the machine performance, the machine speed is controlled below 120m/min. The initial tension and taper selection of the winding is determined by the type and specification of the material, with a moderately tight winding and a wrinkle-free film.
5. When curing, different types of glue should be done according to the manufacturer's requirements. The temperature and time should not deviate too much from the requirements. The temperature deviation should be within 5 °C. The time deviation should not exceed 4 hours. The curing time is not enough and the length is not long. take.
6. The matured material should be cooled at room temperature for more than 12 hours before it can be cut into bags.
7. The selection of composite high temperature cooking glue must be well matched with ink and film. If it is not properly matched, there will be a phenomenon of separation from layer after high temperature cooking. Therefore, before mass production, sample test must be done.
8. According to the characteristics of the glue, each layer of ripening can be selected for 12~24h. After the final layer is completed, the final curing is completed according to the curing time required by the glue. It is also possible to complete the post-maturation chamber by multi-layer one-time compounding, and complete the final ripening according to the curing time required by the glue. The advantages of layered maturation are stable quality, reduced the impact of composite wrinkles, and also the presence of white spots on the composite AL product; the benefits of one-time completion are high productivity and easy management, but wrinkled Quality hazard. Our suggestion is that the segmentation will be sub-staged and the quality will be relatively high.
Bag making process
1. Before batch bag making, sample test is to be carried out to determine the processing parameters, including the temperature, pressure and machine speed of each segment of the heat sealing knife, and these parameters can ensure that the heat sealing strength before and after cooking can reach the standard. The content of the same capacity is loaded into a high temperature cooking tester to test the resistance of the medium to determine the conformity of the material structure.
2, to ensure that the film before the bag is fully cooled, and the composite strength between the layers, the solvent residue of the film has been tested, and the first inspection item has been confirmed.
3. The width of the heat sealing edge when making the bag is not less than 5mm. In addition, in order to ensure the flatness and beauty of the heat sealing area, the cooling mold must ensure a sufficiently low temperature, generally below 25 °C. Fully check the circulation of the cooling water.
4. The adaptability evaluation of the film roll during the bag making process should be sufficient to ensure smooth filming at each production, good heat sealing condition, and stable bag making quality. In particular, RCPP is used as a heat seal layer, which tends to cause poor opening of the bag, and it is necessary to prevent the bag from being knotted due to poor opening. The friction coefficient should be controlled before production, and it is recommended to be in the range of 0.15-0.18 COF.
5. Due to the particularity of high-temperature cooking materials and processes, the sampling rate of high-temperature cooking products should be appropriately increased during the bag making process, so that the quality of the process can be detected early, and the cooking test should be done once in a production shift. To be correct, simulate the customer's conditions of use, that is, enclose the contents of the same capacity and the same nature, according to the customer's sterilization conditions (mainly cooking temperature, time, pressure, such as conditional parameters are 121 ° C, 40 min, 0.2 ~ 0.24 MPa) The detection of high temperature retort resistance is carried out.
6. According to the size and weight of the bag to choose the right amount of packaging, pay attention to protection, to prevent mechanical damage to the bag.