Gravure printing quality control of the hottest pl

2022-09-27
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Gravure printing quality control of plastic flexible packaging materials at present, most products are produced by gravure printing. The quality of gravure products will be affected by many aspects, such as film, ink, plate ink, plate roller, equipment and production workers' operation. Here are some key points of gravure process quality control

commonly used flexible packaging printing substrates are usually as follows: biaxially stretched BOPA, BOPET, BOPP and their derived films (such as K coating, extinction film, pearlescent film, heat sealing film, glass evaporation film, etc.). PP and PE films not stretched. PP, PE or P and VC new mixed buffer materials will produce heat shrinkable films on demand through Pregis' airspeedhc versa equipment. Cellophane or plastic tear film. Other plastic film or paper. Different printing substrates have different adaptability to printing and compounding. Different production processes need to be selected during printing in order to achieve better quality

bopp is the most commonly used printing substrate. Polyamide or chlorinated polypropylene ink is used for printing. With appropriate tension and embossing force, the drying temperature is controlled below 80 ℃. Key points of BOPET printing: because pet is usually thin and easy to wrinkle, it requires a large tension during printing, and has a certain selectivity for ink. With general printing ink, it is easy to separate layers, and the film is electrostatic, which is easy to block the plate (not on). An important point is to know the size range of the sample and the phenomenon of scratch marks (knife threads). It is beneficial to have a high humidity in the workshop during printing

bopp printing points: BOPP is a film prone to moisture absorption and deformation. When printing, the environmental humidity of the printing machine must not be too high (if there is no dehumidification measures, it is not suitable for Indonesia Dragon film in a high humidity environment); The nylon film should be preheated immediately after opening the seal (if there is no preheating device on the machine, the printing plate can be installed after the second color, and the first color can be used as preheating). The preheating temperature is 50~80 ℃; The printing tension should be properly reduced, and the pressure should be suitable for the electric ink. The ink should be adaptable, depending on the different product structure. If it is a cooking bag, the cooking ink must be selected; The printed products must be packed tightly and stored in the drying and ripening room for compounding as soon as possible

k coating film (Kop, kPa, kpet) printing points: because the thickness uniformity of K coating film is not very good, the surface is uneven, and PVDC is rigid and brittle, when the product has a certain market share, the printing tension and embossing pressure should not be too large, the overprint is difficult, the ink transfer is poor, and it is easy to have spots (some spots are lost) when printing a shallow version, so it is necessary to use a high hardness roller for printing. The solvent should be selective. If the solvent is used improperly, the coating may be dissolved. The residual solvent of the printing film is large and easy to adhere. Therefore, special attention should be paid to drying and cooling

the process of OPP can be used for the printing of extinction film, and the inner printing can be carried out on its smooth surface. However, because the extinction layer on its surface cannot withstand high temperature, it is necessary to control the drying temperature. Surface printing ink shall be used for surface printing of pearlescent film, and surface printing ink with good transparency shall be selected as far as possible. When printing the heat shrinkable film, a very low drying temperature should be used, and a special heat shrinkable ink should be selected (the printed ink layer should be able to shrink without falling). If it is a PVC heat shrinkable film, the solubility of the solvent to the film should also be considered

when printing PP and PE films without stretching, the tension should be very small, and it is difficult to overprint, so the printing deformation should be fully considered in the pattern design. For different printing substrates, adjustments must be made in ink selection, plate making design and printing process to ensure that the quality of products meets the requirements; In addition, some high barrier coating materials should not be printed on the coating as far as possible under conditions to prevent damage to the barrier coating

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