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Reason analysis and solution for poor peel strength of high temperature aluminum foil composite bag

In the coastal areas of Zhejiang Province, my country, due to the high temperature and high humidity in summer, the production structure isPA1.5/AL0.7/CPP11.5when the high temperature cooking bag (121℃, sterilization40minutes), appearsPAlayer withALThe layer has basically no fastness, and the adhesive layer is flexible and seems to be stuck, but it is not. The reasons for this situation are roughly as follows: 1, The weather is high temperature and high humidity, and the water vapor content in the air is high, which can causePAThe layer absorbs moisture, contains moisture, and reacts with the glue after applying the glue, consuming part of the curing agent. 2, When compounding the glue, the water and alcohols in the diluting solvent ethyl acetate exceed the standard, and part of the curing agent is also consumed, so that the glue layer cannot be completely cross-linked and cured. 3, Nylon surface wetting tension value is low, which is44dyne, but throughPAFloor/ALThe layer was peeled off, and it was found that the adhesive layer was basically transferred toPAlayer,ALLayers are essentially glue-free, statingPAThe surface wetting tension of the layers can also meet the lamination requirements. 4, Insufficient amount of glue, working fluid concentration28%, although the anilox roller is100mesh, but it has been used for a long time, and the network cable depth is close to120The amount of glue applied is3.49grams, should ensure that the dry basis content reaches4gabove 5, The residual grease on the surface of the aluminum foil causes the adhesion to decrease. 6, When compounding, the speed is fast, the compound drying tunnel temperature is low, the air volume is small, and the fuselage is short.The solvent is not fully volatilized, the solvent cannot be completely volatilized after winding and curing, and the residual solvent is too much. The residual solvent is in the adhesive layer, and the swelling reduces the fastness and adhesion of the adhesive layer. Solution: 1,PAAfter the film is opened, it must be used immediately. If it is not used up, wrap it with aluminum foil and seal it for next use. It is best to cure it in a curing room.1–2Hours. 2, Before dispensing glue, check whether the purity of the solvent exceeds the standard and is qualified. 3, try to usePARubberized surface, wetting tension, for52Dyne’s nylon film. 4, Increase the concentration of the working fluid, increase the amount of glue, confirm the depth of the screen roller, and ensure that the dry basis content reaches4gabove. 5. Carry out grease detection on the aluminum foil composite layer to see if there is excess grease. If it is not qualified, stop using it. 6,becausePAIn the environment of high temperature and high humidity, the moisture content of film and ethyl ester exceeds the standard, so the compounding speed should not be fast, but should be moderate. The residual solvent should be evaporated and dried as much as possible, and the temperature and time of aging should be increased and prolonged.

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