Hot Melt Technology and Azura Chemical-free Processing Plate (2)

The principle of hot melt technology

Hot-melt technology is one of the development directions of CTP plate, and it is the patented technology of AGFA. The basic principle is that the plastic glue particles have the effect of thermal fusion after exposure and condense on the surface of the plate to form a graphic. As shown in Figure 2.

Figure II principle of hot melt technology

Hot-melt technology plate coating is plastic particles coated on hydrophilic media (aluminum substrate). When unexposed, the individual, polymer-polymerized microparticles are tightly packed and fixed by a stable, water-soluble adhesive material that prevents fusion effects (Figure 3). The hot-melt technology plate has good storage properties, and it can be stored for more than 2 weeks at 50oC.

Figure 3 Unexposed plastic particles under an electron microscope

After exposure of the plates, the plastic particles fuse together at high temperatures to form a graphic. Figure 4 shows the plastic particles before and after exposure. Figure 5 is a cross-sectional view of the plastic particles that were fused together after exposure. It clearly shows how the plastic particles are together.

Figure 4 Plastic microparticles under electron microscope before and after exposure

Figure 5 Cross-section of heat-fused microparticle layer after exposure

The plastic particles are precisely designed to ensure a stable ink-receptive layer after exposure and fusion, and remain stable under the action of printing syrup (cleaning solution, alcohol and other solvents). The smaller the particles, the less energy is required for thermal fusion.

Unfused plastic particles exposed after cleaning aluminum plate, blank part of the printing plate. There are many ways to clean. One of them is the direct cleaning by the water roller of the printing press. The AGRIT's Thermolite plate is used in this way. Based on the same principle, the Azura plate is rinsed with glue. On the one hand, it ensures cleanness and thoroughness. On the other hand, the protective glue is applied to the surface of the printing plate to protect the printing plate.

Aluminum plate in hot melt technology

Compared with other processing-free technology plates, the most important feature of hot-melt technology is the direct use of hydrophilic aluminum plate as the hydrophilic layer of the printing plate, and its printability and resistance to printing force have very good performance.

At present, more than 90% of printing plates use aluminum plate base. The aluminum plate base is generally subjected to electrode sanding, anodization, sealing and the like, and then coated to form a printing plate.

Figure 6 shows the aluminum plate and 2x2 dots after exposure and Figure 7 shows the anodized layer.

Figure 6 Aluminium substrate and 2X2 dots under electron microscope

Figure 7 Anodized layer

Azura Chemical-free Processing Plate

The Azura plate consists of a plate base and a film layer. The base plate is ground, oxidized, and sealed. The drug film layer is a plastic particle, which is adsorbed on the surface of the plate by a water-soluble material. As shown in Figure 9.