2. Influence of the solvent The solvent used to formulate the ink also affects its ability to adhere. As we all know, the solubility parameters of the resin and the solvent used are similar, and the solubility parameters of the steel drum surface coatings must be considered at the same time.
1 The solubility parameters of resin and solvent are similar, which is conducive to dissolution.
2 Excessive use of high-boiling solvents, the ink adhesion decreased.
3 improper use of solvents, ink adhesion is poor. The use of solvents must be considered from a variety of factors, so ink solvents often use more than three mixed solvents.
(4) The solvent and binder in the ink (high molecular polymer) are in contact with the drum surface coating and swell and dissolve the coating material on the surface of the drum, so that the binder in the surface coating of the drum and ink can be mutually dispersed. The formation of a layer of mixed, unbounded intermediate layers leads to the disappearance of the interface and the formation of a strong bond between the ink and the surface coating of the drum.
The diffusion process is the process of the ink solvent dissolving the paint coating on the surface of the drum, and the dissolution of the paint coating on the steel drum depends on the polarity of the binder and the solvent in the ink. Only when the polarity of the ink and steel drum surface coatings are similar, can they be dissolved and have adhesive fastness.
The binder in the ink is generally a molecular polymer having a linear structure, and the molecular ends thereof are easily diffused into the paint coating on the surface of the steel drum. The short side chains are not conducive to diffusion, and the large branch chains are conducive to diffusion.
The linking material has a large molecular weight and a long chain length, and has slow penetration and slow diffusion. When the molecular weight is small, the permeation is quick and the binding force is large, but the cohesive strength is small in itself. Therefore, the high-molecular polymer as a linking material needs to have an optimum molecular weight, which facilitates diffusion and has a certain cohesive strength.
The binder is sensitive to temperature during the diffusion process of the coating on the surface of the drum. Increasing the temperature can promote the Brownian motion of the macromolecule, which is beneficial to increase the speed and capability of diffusion, and is also beneficial to the fastness of the ink. This is the reason why the printing speed of the ink is fast and the adhesion is good when the graphics are printed on the surface of the drum in the summer, and the drying speed is slow in winter and the adhesion of the ink is also poor.
3. Effects of additives A wide variety of additives will greatly improve the performance of the ink. Additives that have an effect on adhesion are:
1 Crosslinker. The cross-linking agent can not only improve the adhesion of the ink, but also can greatly improve the ink's hardness, water resistance and drying speed.
 2 coupling agent. The coupling agent promotes coupling of resin and the surface coating material of the polymer drum in the ink, and can improve the adhesion of the ink.
3 plasticizers. The plasticizer improves the softness of the ink film and also improves the adhesion.
4. Effect of ink properties
The wettability of the ink is good, and its adhesion is favorable. If the surface of the drum has not yet been wetted, the ink has dried or cured and the adhesion is poor.
1 When preparing the ink, the volatilization rate of the solvent must be controlled, and the presence of the high-boiling solvent is advantageous for leveling.
2 Use an appropriate molecular weight of the resin to formulate the ink. The higher the viscosity of the resin, the more unfavorable the leveling of the ink.
3 Add an appropriate leveling agent to the ink. (To be continued)
Heating pad is a self-heating hot compress physiotherapy product with a duration of clinical testing of 8 hours, which can reduce or eliminate painful women's dysmenorrhea and waist soreness.
The raw material layer is a polymer synthesized from ginger powder, iron powder, stone, activated carbon, inorganic salt, water, etc., which is non-toxic and has no side effects, and can undergo an exothermic reaction under the action of oxygen in the air.
When in use, stick to the shoulders, back, waist, stomach, legs and related joints;
When in use, you only need to stick to the corresponding part, and it will immediately heat up, with an average temperature of 40°C;
Used for abdominal pain caused by cold, to keep warm when working outside, and to keep warm in the room when the temperature is low;
Outdoor activities in winter can prevent muscles from being too cold and tense, prevent frostbite of hands, prevent colds, or relieve back pain, leg pain, shoulder pain and other physical pains.
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Jilin Xiangqi Technology Co., Ltd , https://www.xiangqicosmetics.com