1. Preparation of substrate film
There are many kinds of carriers for heat transfer film. PET is widely used. It has the characteristics of good dimensional stability, uniform tension, good heat resistance, and good release properties. Especially in the reproduction of color gradation originals, it has obvious advantages. The specifications of the film, such as width, thickness, and brand, are selected according to the manufacturer's requirements. At the same time, check the flatness of the film and whether the tube material has "protruding ribs" or "flounces" that do not meet the quality requirements.
2. Preparation of release agent
Release agent is a low-viscosity transparent resin with release properties, film-forming properties and adhesive properties. Because the solvent in the release agent evaporates faster, it is necessary to control the viscosity during the coating process, that is, control The solid content of the release agent is generally controlled at about 23%. If the solid content is less than 19%, the transfer effect of the thermal transfer film after coating the release agent is not ideal. At the same time, pay attention to the transparency of the release agent, otherwise it will affect the effect of the printed layer.
3. Preparation of ink
Thermal transfer inks are gravure inks. The drying of the ink mainly depends on the volatilization of the solvent. After the substrate film is determined, the appropriate ink should be selected according to the purpose of the printed matter and the nature of the printing material or according to the requirements of the construction order. Check the fineness, viscosity, hue, tinting strength and other indicators of the ink to see if all meet the printing quality requirements for the ink.
4. Preparation of adhesive
The adhesive for heat transfer is a hot melt adhesive, which is a colorless, transparent or light yellow viscous liquid. After coating and drying to form a film, the film is transparent and has excellent composite firmness on the surface of the coated release agent and ink. Degree and excellent flexibility, abrasion resistance, strong resistance to media such as water, acid and alkali, and good weather resistance.