Causes of silica gel poisoning and preventive measures
作者:周周 日期:2019-09-11 15:22 浏览:
Silica gel itself has the characteristics of low temperature resistance, high temperature resistance, yellowing resistance, strong elasticity and adhesion. Therefore, silica gel is used as one of the common glue for dispensing and plays an important role in the production of electronic communication industry. However, once silica gel is combined with nitrogen, phosphorus, sulfur and other organic substances in the process of dispensing of double-liquid dispenser, chemical reactions will occur quickly. This is the phenomenon of silica gel poisoning.
Reasons for poisoning caused by silica gel coating on dispensing machine: When using silica gel, the addition reaction of silica gel is needed, that is, the addition reaction of silica hydrogen bond and cinnamyl vinyl bond occurs in silica gel. Because the addition reaction requires metal platinum, when they are mixed, compounds will be formed. This compound is an unstable substance! This mixture is easily affected by some substances to change the chemical structure or the structure of compounds. At this time, it is easy to lose the catalytic activity of hydrosilane and vinyl bond, which leads to the occurrence of silica gel poisoning.
If the added silica gel reacts with any substance, it can react with the catalyst "platinum" during curing or curing. Under normal curing conditions, the added silica gel can not be cured (the state before and after the reaction is still liquid) or can not borrow the required elasticity after curing or after the surface becomes viscous after curing. Body or hardness), this is the "poisoning" phenomenon.
One of the obvious characteristics of silicone poisoning in double-liquid dispenser is that silicon does not solidify. Therefore, in order to avoid silicone poisoning, it is necessary to avoid contact with organic compounds containing phosphorus, sulfur and nitrogen, or to avoid using polyurethane, epoxy resin, unsaturated polyester, condensated room temperature vulcanized silicone rubber and other products at the same time. When using different types of silica gel in our double-liquid dispensing machine, we must gradually clean up the residual silica gel in the original equipment from the barrel to the dispensing pump so as to effectively avoid the occurrence of silica gel poisoning.