Production of heat transfer printing film

 

Before the thermal transfer film is printed and printed, it must be carefully analyzed and studied according to the customer's requirements, and then carried out according to the printing process steps.

 

1. Preparation of substrate film

 

There are many kinds of carriers for thermal transfer film, the most widely used is PET, which has the characteristics of good dimensional stability, uniform tension, good heat resistance effect and good release properties. In particular, it has obvious advantages in the reproduction of color tone originals. The specifications of the film such as width, thickness and grade are selected according to the manufacturer's requirements. At the same time, it is necessary to check the flatness of the film and whether there are "ribs" and "lotus leaf edges" in the tube material that do not meet the quality requirements.

 

2. Preparation of release agent

 

The release agent is a low-viscosity transparent resin with release, film-forming and adhesive properties. Because the solvent in the release agent volatilizes faster, during the coating process, attention should be paid to controlling the viscosity, that is, controlling The solid content of the release agent is generally controlled at about 23%. If the solid content is lower 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 printing layer.

 

3. Preparation of ink

 

Thermal transfer ink belongs to gravure printing ink. The drying of ink mainly depends on the volatilization of solvent. After the substrate film is determined, select the appropriate ink according to the use of the printed matter and the properties of the printing material or according to the requirements of the construction sheet. Check the ink's fineness, viscosity, hue, tinting strength and other indicators to see if all meet the printing quality requirements for the ink.

 

4. Preparation of the adhesive

 

The adhesive for thermal transfer is hot melt adhesive, which is colorless, transparent or light yellow viscous liquid. After coating and drying to form a film, the film is transparent and has excellent composite fastness on the surface of the coated release agent and ink. High degree of flexibility and excellent flexibility, abrasion resistance, strong resistance to media such as water and acid and alkali, and good weather resistance.