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Factors of surface wrinkling after high temperature cooking bag sterilizationIt is found that the phenomenon of surface wrinkling should be carefully observed and accurately analyzed, if the printed substrate has vertical, horizontal or irregular wrinkles. The analysis is mainly considered from three points:a.The temperature of the drying tunnel is too high during printing, the constant tension between rewinding and unwinding is inconsistent, and the unwinding tension is too large.PETThe film is deformed.b.The paper core of the rewinding roll is not smooth. Due to the continuous increase of the volume of the rewinding product, longitudinal or transverse wrinkles will occur at the bottom of the rewinding, making the originally flat printing substrate uneven. This wrinkling phenomenon occurs during the compounding process. Not easy to remove.c.The printing traction roller has foreign objects or is too dirty. When the printing substrate passes through the foreign objects, it slides laterally. When the sliding substrate passes through the embossing rubber roller, wrinkles are generated. These wrinkles are regular, and there is no section in one section.Solution:a.Adjust the drying temperature according to the temperature and humidity of the workshop, the speed of the machine, and the depth of the actual printing effect pattern. For most retort pouches printed on nylon15μm,PETfor12μm, so the recommended drying temperature is40-60℃ is better. If the drying temperature is too high, the film will not be able to withstand the high temperature and will be deformed, elongated and softened. To adjust the constant tension of rewinding and unwinding, there are high-speed gravure printing machines that have produced automatic adjustment tension controllers. When the limit or set value is exceeded, it will automatically alarm, and automatic adjustment is very convenient.b.Replace the paper tube with a smooth center of the circle, and pay attention to the flatness when winding. The winding tension should be small at the beginning, and then slowly increase the tension value when it reaches a certain thickness, so that the winding material will not be wrinkled.c.Wipe the traction roller with foreign objects clean.When the surface of the substrate and the composite substrate is wrinkled together, the flatness is extremely poor. The factors are:a.The wrinkling of the printing substrate itself or the wrinkling during printing cannot be eliminated;b.When compounding, when the pressure at both ends of the hot steel roll is inconsistent or the base material is compoundedPE,CPPThickness deviation is large, when the deviation10μmThis kind of wrinkle phenomenon is very easy to appear;c.A phenomenon that occurs when the bottom tension is too small and the top tension is too large when winding the composite product.Solution:a.Strictly control the printing quality;b.Adjust the pressure of the steel roller to a balanced state, and try not to deviate the composite substrate. When the middle of the composite is aluminum foil, the traction roller should be worn as little as possible to prevent the phenomenon of breakage;c.Adjust the winding tension to be as consistent as possible.When there are wrinkles on the substrate and there are bubbles in the middle, it is most likely that the tension is not well controlled during dry lamination, the tension is too high, and the tension is too tight. existNY/PEorNY/aluminum foil/CPPMost prone to occur, especially with nylon substrates. If the unwinding tension is too large, heat shrinks and deforms during the drying tunnel, and this phenomenon occurs after the finished product is cooled; due to the influence of the glue, the dry solid content must be reached when coating the high-temperature cooking bag.4.5g/m2, the screen roller is generally selected80μmDeep enough, if the coating is uneven, or the quality of the glue itself is poor, it is easy to cause the glue to separate from the substrate after boiling, which greatly reduces its fastness.Solution

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