When not familiar with using silicone sealant, or when handling liquid silicone for the first time, bubbles may sometimes appear. What are the reasons for this and how should we deal with it? Below, Hongtu will explain to you.
1, the air bubbles introduced during the mixing or gluing process have not been completely eliminated. During the glue adjustment process, due to the high viscosity of the glue or improper mixing method, it is easy to introduce air into the glue solution. If the viscosity of the glue solution is high, it is difficult to eliminate bubbles. If the viscosity of the glue is low and the glue solidifies slowly, the bubbles will slowly float to the surface and automatically disappear.
2, bubbles generated during the solidification process. There are also several reasons for the formation of bubbles during the curing process: too fast curing speed, high heat dissipation temperature, large shrinkage rate of the adhesive during curing, and excessive solvent and plasticizer addition in the adhesive, which can easily generate bubbles during the curing process. Another issue is that the formula of silicone contains a small amount of volatile impurities, which can vaporize and form bubbles during heating and curing.
There are several methods to avoid or remove bubbles in liquid silicone gel for reference.
For the first reason, vacuum pumping or centrifugation can be used to solve it. You can also take the method of letting it sit for a period of time (30 minutes to 2 hours) and wait for the bubbles to float up on their own. If there is no vacuum machine, stir in a clockwise direction for 2-3 minutes. After stirring evenly, leave the glue for 5-20 minutes for automatic defoaming. However, this method is only suitable for silicone gel with thin viscosity. If the silicone gel is thick, the bubbles trapped in it will not be easy to rise and be discharged.
For the second reason, the bubbles caused by volatile impurities in the silicone formula can be eliminated by low-temperature baking, allowing these impurities to evaporate first and then increasing the temperature for curing, so that there are no more bubbles. To solve the problems during the curing process, it is necessary to adjust the overall formula of the silicone gel.
The above methods are hoped to be helpful to you. Follow us to learn more about liquid silicone gel knowledge.
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