Analysis on the Causes and Countermeasures of the Drum Bag of Epoxy Resin Floor in PCB Factory
Epoxy ground drums are generally found shortly after the construction, and some morning paving the epoxy ground afternoon there are drums. Drums from small to large, continuous development, development to a certain extent after the rest. The higher the temperature, the more prone to drums, the faster the pace of development. Drum shape different, its size varies. Some drums up to 1cm in diameter, height of 20 ~ 50mm. There is no significant relationship between the production of the drums and the construction area. Some of the same areas are grim, some are lighter and some are good. The same group of manipulation, the same material construction of the epoxy floor layer, and some from the drum, and some intact, indicating that the package is caused by a variety of factors. The reason for the drum is that we are concerned about a subject, cut open drum package found that the package contains water or yellowish liquid, epoxy layer and the base layer from the sticky layer of cementing material was pulled into a peak nest.
So where does the water come from?
There are several sources of water:
1, grass, such as cement mortar leveling layer, the maximum water content of about 12%, the grassroots maximum water content is greater than leveling layer;
2, epoxy in the other ingredients within the dehydration;
3, the combination of epoxy and grass-roots construction is not good to leave the open field and the chemical activity of epoxy itself, there is no fully cured residues or gas;
4, the base of the underground infiltration of gas exudation.
From the above four aspects to analyze, grass-roots moisture is the main, absolutely dry grass is not. Some of the grass-roots water vapor and epoxy residues are wrapped in epoxy and grass-roots, the formation of different sizes of bubbles, because the epoxy layer itself is not moisture, water can not be discharged, leaving the drum root seedlings. Therefore, the drums are produced in the plane, more in the grass and epoxy layer. The water in the grassroots level is difficult to avoid, which is caused by the important role of epoxy layer drum.
With the day and night and the atmospheric temperature is constantly changing, or slowly rising, or slowly reduced. The water inside the package condensed into small water droplets, the pressure also will be reduced, because the muster of the epoxy layer has a certain intensity, drum can not be restored to the original, so that negative pressure inside the drum, so that the grass layer contains water Of the moisture inhalation, so that the water produced within the package increased.
When the second day of heating, because the package can increase the evaporation of water, but also produce greater pressure, so that the volume of drums and expand, from the open drum base found in the base of some small white spots, Grass-roots connected to the water channel. People put this development of the drum called "live bag".
When the drum package to a certain size, because the grassroots dry, broken the "water", but also because of large and flat package, reducing the upward tear strength, and some drums at the epoxy layer by the role of high temperature steaming. With the temperature of the lift, the epoxy layer by the tension when the small, so that the epoxy layer of fatigue and aging. Then part of the drum of the epoxy layer in the role of external damage under the first. Directly damage the aesthetic and durability of the epoxy layer.
It is necessary for the actual situation of the project, take measures to prevent the production of drums.