Hot melt glue are commonly known as EVA (ethylene-vinyl acetate copolymers). The formulations vary slightly depending on the industry in which they are used. However, hot-melt adhesives for printing should also be differentiated according to different applications.
1. Should different types of glue be used for binding different papers?
For example, binding plain paper or coated paper? Copperplate paper should be made of copper plate glue; the top-mounted glue pot wireless glue machine or the bottom-mounted glue pot wireless glue machine? The glue pot on the top-mounted glue pot should use the glue with long opening time.
(Note: The open time of the hot melt adhesive refers to the time when the glue liquid condenses. This time is generally 6-13 seconds.)
2. How long should the finished books and magazines be placed before cutting?
Should be cut in the hot-melt adhesive cooling hardening stereotypes, this time should generally be guaranteed in more than 3 minutes, otherwise there will be book spine deformation, plastic sticky knife and other issues.
(Note: The cooling and hardening time of EVA hot melt adhesive is generally more than 3 minutes)
3, plastic pot temperature should be how to adjust?
First, according to the technical specifications provided by the manufacturer of hot-melt adhesives as a reference, too high or too low will reduce the bond strength and tensile strength, so the temperature of the hot-melt adhesive must be controlled within a certain range in order to achieve the best Bonding effect.
In addition, depending on the texture of the paper, the glue temperature should also be different. For example, the inorganic content of coated paper is about 10 times higher than that of offset paper and writing paper, and the inorganic material has good thermal conductivity. It will accelerate the cooling of the hot melt adhesive. Curing speed, so this situation should slightly increase the temperature of the plastic pot.
4. What requirements does the EVA hot melt glue have on the use environment?
In general, the temperature is maintained at a constant temperature of 20-25°C, and the humidity is maintained at about 50% so that the binding effect can be optimized.
5. How long should the completed glued books be delivered for use?
Generally, it is delivered immediately at the digital quick printing shop. Of course, there is no problem as an ordinary use, but it is not possible to read it at this time because the bonding effect of EVA hot melt adhesive is best after 24 hours.
6. What are the reasons for a page drop in the user's use?
In addition to the problems mentioned above, it is usually necessary to pay attention to whether the equipment debugging is appropriate and whether the operation method is correct. Another problem that is easily overlooked is that many plastic blocks are added at one time during the operation. However, due to the small amount of work performed each time, the EVA hot melt adhesive is repeatedly heated and melted, which destroys the macromolecular chain structure and reduces heat. Melt viscosity. This situation is more common in digital printing shops
Source: Print Channel
