As we all know, silicone sealant can be divided into acid silicone and neutral silicone. Acid silicone sealant has very good elasticity and adhesion, and its use range is very wide. It can be used for bonding between most decoration building materials. Such as glass, aluminum, non-oily wood, etc. However, it should be noted that acid silicone sealant cannot be used to stick alkaline building materials such as ceramics and marble. Otherwise, the substances in the acid silicone sealant will react with the alkaline substances in the building materials, thus affecting the decoration quality of the building materials. Let's take a look at the actual problems that are prone to occur with acid silicone sealant:

1.During the extrusion process of the acid glue, the flow will be cut off or there will be small bubbles, why?

This is mainly due to the following two reasons.

One is caused by the storage temperature being too low: if the acid silicone (especially the low-grade) is stored at a lower temperature, a lot of bubbles will be formed. The reason may be that after low temperature storage, the liquid raw material will form more bubbles due to the change in volume of cold shrinkage, so it is recommended that the storage temperature should not be lower than 5℃.

The second is the formation in the canning process: in normal canning, there are often a small amount of small bubbles at the end of the stick. It must be improved and should be avoided. However, this situation also has a probability of occurrence. If such a phenomenon occurs rarely or occasionally, it should be regarded as an accidental event. Large bubbles should be avoided as much as possible during operation.

2.Why do some acid glues make aluminum discolor after curing?

When the acid silicone is cured, it will release acid, which is corrosive to metal materials. The reason why it can be used on aluminum is that the surface of the aluminum is protected by an oxide film or coating. So generally speaking, discoloration of aluminum is not a problem of silicone. It should be more about construction operations and the quality of aluminum itself. The quality of aluminum material mainly refers to the unqualified coating layer of the coated aluminum material, such as poor adhesion, too thin film layer, etc., which will cause discoloration after sizing; improper construction will also cause discoloration. In a poorly ventilated environment, the acetic acid released by the curing of the glass glue cannot be dissipated in time, and the local concentration is too high, which will corrode the aluminum material for a long time and cause it to change color.

3. Why does the glass glue shrink after curing?

All sealants shrink after curing, but high-grade and low-grade silicone sealant have very different shrinkage rates. For example: high-grade silicone sealant shrinks only 5% after curing, low-grade silicone may shrink by 30% or more, this is because low-grade silicone is added with filler, and the filler will slowly volatilize in the air, so the more the filler, the shrinkage rate is higher.