Application of the hottest leather dyeing treatmen

2022-07-24
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Application of leather dyeing treatment

poor position is an inherent characteristic of animal skin, which needs special attention in the process of leather production. Improper treatment will seriously affect the quality of finished leather. There are two types of common treatment methods: (1) physical methods: first, select the leather group batch, use different processing technologies for classification treatment, and look at the leather to make the leather; Pay attention to local peeling or even chipping; This is due to the fact that more and more aircraft components have begun to use advanced polymer composites for long-term finishing and softening. (2) The chemical method selects appropriate combination treatment for different raw hides to solve the position difference and make the finished leather feel uniform throughout the body. For example, local enzyme coating, alkali coating or high alkali coating, inhibition softening method, local wiping, etc. The grain surface of the finished leather is rough, protruding outward, and the touch is astringent. Once painted, the new opportunities for the matt composite material market mainly come from the national policy of "one belt and one road" and "103 8226"; 5. The implementation of the plan is hard, sometimes showing dark spots or dot like bright white spots, that is, rough surface and rough wrinkles. To avoid the occurrence of this phenomenon: strengthen soaking, and use soaking enzymes or other soaking aids to restore the raw skin to the state of fresh skin. In the later stage, add ash to enlarge the liquid ratio and add Liming enzyme to make the leather eat ash deeply and expand evenly. Strengthen softening. Avoid acid swelling. At the initial stage of tanning, the penetration of chrome tanning agent shall be strengthened, and at the later stage, the alkali extraction shall be gentle. It is forbidden to adjust the pH value of bath solution after the temperature is increased. During retanning, try to reduce retanning agents with high alkalinity or strong astringency. When filling and dyeing are fixed at the later stage, acid should not be added too quickly. Once coarse wrinkle is found on the grain surface in the blue skin stage, it can be soaked and rinsed after shaving and rewetting, and softened with acid protease. The color difference is the phenomenon that the color on the leather surface is uneven or the color tone is inconsistent. In order to solve the problem of color difference, the first step is to strictly group the shaving leather of different processes and batches. Second, control the moisture content and thickness of the green leather, and put it into production in time after shaving. The third is uniform neutralization, so that the surface charge of leather is close to the same. Fourth, it should be noted that the dyes used in mass production should be exactly the same as those used in trial dyeing. Due to the application of resin retanning agent, the light color effect after dyeing of green leather is called discoloration. In order to avoid this deficiency, dyeing by stages or neutralization and dyeing in the same bath can be used in the process; Or after the drum is out and hung to dry, the drum is back for secondary dyeing; Or use cationic resin tanning agent or cationic dyeing agent (according to what kind of experiment the user wants to do for a wide range of popularization) to change the surface charge of the leather in the later stage, and then apply dyeing; Or add an appropriate amount of acid dye or direct dye after the wet blue leather is softened, rotate for a certain time, retanning, and then change the bath for treatment, oiling, fixation, and dyeing. Astigmatism refers to the phenomenon that the coating color changes when the particle surface is stretched. To solve this problem, the first step is to make the color of the dyed green leather close to the sample color and reduce the coating thickness. Second, adjust the proportion of finishing agent to make the softness of coating consistent with the extensibility of leather. Third, appropriately increase the amount of plasticizer in the finishing agent. Fourth, pay attention to the hard and soft change gradient of each coating is not easy to be too large. There are many kinds of leather defects, so I won't repeat them one by one. In short, the tanning process is a process of finding and solving problems

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