What are the basic requirements of YLTpacking packaging bag printing for the substrate? (1) The surface of the printing substrate should be smooth, free of impurities and damage; (2) For non-polar materials, the surface should be treated to improve the surface energy, and the surface tension of the printing substrate should be above 36mN/m; (3) ) The printing coil should not be too loose, especially not tight on one side and loose on the other side; (4) The shrinkage and elongation of the substrate should be less than 1% under the best printing conditions; (5) The substrate should have a certain resistance Tensile strength and rigidity. For a wide variety of packaging and printing substrates, YLTpacking warns that the following issues should be especially considered: (1) Transparent films and non-transparent films, such as paper, aluminum foil and other non-transparent films are opaque and can only be printed, while most plastic films are transparent , can be printed inside. (2) Fast-drying solvents should be used as much as possible when printing substrate films such as films that are greatly affected by solvents, so that the solvent in the ink stays on the surface of the film for as short a time as possible, and can be quickly volatilized, so that the substrate film cannot be swelled in time. or dissolved. In addition, the amount of hot air for drying should be appropriately increased. FS or PC films are easily dissolved by most organic solvents other than ethanol, resulting in film breakage or adhesion. PVC and EVA films will swell due to ester or ketone solvents, especially PVC shrinkable films, which will shrink due to the action of the solvent in the ink, resulting in inaccurate color registration, and the ink is not easy to dry. (3) Films such as PT, PVA, PA, etc., which are easily affected by moisture, have strong affinity with water, and are easy to absorb moisture in the air to affect their performance. These films will not only wrinkle or relax during the printing process due to absorbing moisture, but also have a great impact on the printability and compounding suitability of the ink, such as poor printing fastness, blooming, wetting, and blurred edges. , There are compound bubbles, poor compound fastness, etc., so special attention should be paid to the influence of printing environment or changes in season and climate. In actual operation, the first and second color units can be passed through the drying film and then printed. (4) The static electricity of the film that is easy to generate static electricity is generated by the friction of the bad conductor. The film that is easy to absorb moisture has less static electricity, and the printing speed is fast. 5) Films such as EVA, LDPE and other films that are easy to stretch or shrink are easy to stretch, not easy to register, and are greatly affected by heat. (6) When printing the coating film on the coating layer of the coating film, pay attention to the compatibility of the coating material with the ink and solvent resistance. The printing adaptability of the coating film is largely determined by the coating material. performance is determined. When printing with a coating film, the compatibility of the ink and the film should be tested. There are certain processing aids in the coating layer of the coating film, which will affect the fastness after precipitation. In addition, the coating film has a relatively higher residual solvent during printing. .
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