The blisters on the resin floor mostly occur on the first floor or in the basement, and sometimes occur on the second floor or above. The blisters on the resin floor are usually found shortly after construction, and some resin floors on the morning surface have blisters in the afternoon. The blisters continue to develop from small to large, and stop when they reach a certain level. The higher the temperature, the easier it is for blisters to occur and the faster it will develop. The blisters have different shapes and different sizes. Some blisters have a diameter of more than 1m and a height of 20-50mm.
The occurrence of blisters has no obvious relationship with the construction area. Some in the same area are serious, some are light, and some are intact. The same group of operations, the construction of the resin floor with the same material, some blisters, some intact, indicating that blisters are caused by a variety of factors.
The cause of blisters is a problem that everyone cares about. When the blisters are opened, the bubbles contain water or yellow liquid. The resin surface layer is detached from the base layer, and the cement adhered to the base layer is drawn into a peak and nest shape. "Physics" explains that in a closed container filled with liquid, the liquid evaporates to form the relationship between the temperature and pressure of the three curves of saturation.
In a closed container, the pressure of saturated water vapor rises with the increase of temperature. When the temperature is 20.C, the pressure in the drum is 0.01MPa; while when the temperature is between 70~80.C It rises straight to 0.1MPa; in many regions, the extreme radiant heat on the ground in hot summer can reach about 70.C. At such high temperatures, the resin binder has softened and the viscosity is greatly reduced, so it gradually bulges in the same direction tire Like the gas, the resin layer swelled up, and the binder was pulled into a honeycomb shape; the part of the resin layer that did not have blisters was not firmly adhered to the ground part. Careful observation of the contact part will also find that there is a part that cannot be cured. The reason is that the epoxy cannot cure with moisture; so where does the water come from?
There are several sources of water:
1. The base layer, such as the cement mortar leveling layer, has a maximum water content of about 12%, and the maximum moisture content of the base layer is greater than the leveling layer.
2. The dehydration in other ingredients in the resin is endless.
3. The resin and the base layer are not well combined during construction, leaving voids and the chemical activity of the epoxy itself. It is not completely cured or it is a residue or gas that is not completely cured when encountering moisture.
4. Moist gas that penetrates underground at the grassroots level.
From the analysis of the above four aspects, the moisture of the grassroots is the main one, and the absolutely dry grassroots is not. The size of the water content cannot determine whether the ground will produce blisters. Part of the water vapor and resin residues of the base layer are wrapped in the resin and the base layer, forming bubbles of different sizes. Since the resin layer itself is impervious to water vapor, the water vapor cannot be discharged , Leaving bubbly root seedlings. So bubbles are generated on the plane, mostly between the base layer and the resin layer; moisture in the base layer is difficult to avoid, which is an important factor that causes foaming of the resin layer.
The atmospheric temperature changes day and night and seasons, or gradually increases, or gradually decreases. The water vapor in the bag condenses and forms small water beads, and the pressure is also reduced. Because the resin layer that has been bulged has a certain strength, the bulge cannot be restored to its original state, so that the negative pressure is generated in the bulge, which in turn contains water in the base layer. Inhalation of moisture increases the moisture produced in the bag. When the temperature rises the next day, due to the increase in the evaporable water in the bag, it generates more pressure and expands the volume of the bulge. From the base layer of the bulge, there are some small white spots in the peak and nest shape. Water channels connected to the grassroots. People call this developing drum kit "living kit." When the bulge develops to a certain size, the "water source" is cut off due to the dryness of the base, and the flatness of the bulge is also large, which reduces the upward tearing force. Some resin layers at the bulge are exposed to heat and steam. As the temperature rises and falls, the pulling force on the resin layer increases and decreases, which causes fatigue and aging of the resin layer. Then part of the bulged resin layer is destroyed first under the action of external force. Directly destroy the aesthetics of the resin layer, the sealing performance and durability of the clean room. It is necessary to take measures against the actual situation of the project to prevent the formation of blisters.
1. Solve the occurrence of blisters in the epoxy layer, and mainly solve the "three fears" in the construction of epoxy floors (1) fear of water; (2) fear of sun; (3) fear of dust.
2. Take measures to prevent blisters:
(1). Make a waterproof layer on the base layer to prevent moisture from seeping upward. Control the moisture content of the base layer or waterproof layer to be within 8%. The compressive strength of the base layer or waterproof layer is greater than 20MPa. Epoxy construction is carried out.
(2). Improve the adhesive force between the resin layer and the base layer or waterproof layer, overcome the swelling force at the beginning of the blisters to avoid the occurrence of blisters.
(3). In the construction of the resin layer, the primer layer should be made of good quality materials. First, let a part of the resin penetrate into the base layer or the waterproof layer to form a whole. Second, improve the adhesion, and leave little after curing Residual substances or chemical gases.
(4). After the construction of the resin, avoid the sunlight, and reduce the change of the temperature difference between the surface and the inside of the resin layer.
(5). Be sure to clean up the construction on the base or waterproof layer. No gap is left between the resin layer and the base layer or waterproof after construction.
(6) In short, the selection of waterproof materials must have the following points: 1) impermeability and air permeability; 2) compression resistance, strength greater than 20MPa; 3) super adhesion to the ground; 4) and no Saturated resin is easy to bond to form a whole. The waterproof layer shall not be accessible to people within 3 days after construction is completed to protect the finished product.