Reflective heat transfer film precautions
When the material is ready, it can be printed on the printing press. General release layer, printing layer and adhesive layer are all coated on the same gravure printing machine.
The substrate film is placed in the center of the take-up reel, passes through between the platen roller and the plate cylinder, and then passes through a constant tension draw roller to enter the take-up reel, adjusts the paper feeding force according to the diameter of the reel, and uses different materials according to the coating. Set different drying temperatures.
Coating release agent
First, a good release agent is formulated, poured into a coating tank and mixed uniformly, and the coating is applied to a gravure printing machine. The coated substrate film is dried on a drying device. The drying temperature may be based on the temperature required by the release agent or The data provided by the manufacturer is set. Release agent on the surface of the substrate film curing time is very short, but to make the transfer effect is better to make the solvent completely volatile before preparing the coating ink, so the drying temperature can be higher, or in 2-4 colors Dry on the group. The release agent coating thickness is controlled at about 5μm, not too thick or too thin, too thick will make the release layer easily fall off from the substrate film, too thin will cause the thermal transfer printing layer can not be completely transferred.
The printed layer of the thermal transfer film is generally gravure printed. The substrate film roll coated with a release agent passes through the middle of the embossing cylinder and the plate cylinder. The plate cylinder rotates in the ink tank to print the graphic and then goes through the drying device for printing. The ink layer is dried to speed up the drying process. The thermal transfer ink is dried according to its solvent to select the drying temperature. If the solvent is a fast drying toluene, the drying temperature can be appropriately reduced. If it is a slow drying xylene, the drying temperature should be increased. At the same time pay attention to the color printing sequence of the thermal transfer film is opposite to the general printing color sequence, that is, first to print the high transparency ink, then print the low transparency ink, and finally print a layer of white ink as needed. The role of the opaque white ink is to cover the color of the substrate itself, so that the graphic layer and color tone transferred to the colored object are not affected.
Coating adhesive layer
In order not to destroy the graphics of the printed layer, the adhesive layer is to be carried out with the printed layer completely dry. The adhesive layer can be directly coated in the final color set of the gravure printing machine. The coated substrate film is then dried. The drying temperature is determined according to the different substrate films, and finally by winding.
Rolling and cutting
The retraction air inflation shaft is the same as the paper discharge shaft. The winding reeling force is controlled by the rewinding motor to control the traction force of the pulling roller, which is generally the same as the tension at the paper discharge place, so that the machine bed can operate normally. When a reeling shaft is finished, it can be cut and then changed to another shaft. The heat transfer film roll will be cut to different widths as required. In order to save the cost, the thermal transfer graphic is usually made on a printing plate according to the size evenly distributed, and then cut when used. At the same time, the most important thing is that the cutting machine must have an automatic corrective device, otherwise it will affect the overall effect of the graphic.
During the printing process, the release agent, ink and adhesive must be added at any time, and the roll film should be placed on the paper feeding mechanism in time to ensure that the printing is performed normally and continuously. We must also regularly check and inspect the coating conditions of various materials of the thermal transfer film. Whether there are white spots, dirty spots, or streaks on the printed sheets, we should eliminate the printing troubles in time.