What are the precautions for winter construction of silicone sealant?

After winter, the weather is cold, and many people will find that the silicone sealant dries slowly and bubbles after application during the recent construction process. Why did the silicone sealant that I have been using all of a sudden have this problem?

1. The silicone sealant failed to dry after three days of application. What is the reason?

The main reason for this problem is the decrease in temperature. As the temperature decreases, the reaction speed of the silicone sealant will slow down. When the temperature is lower than 20°C, the curing speed of the silicone sealant will decrease, and the curing speed of the silicone sealant will be obviously noticeable. Curing speed decreases. At low temperatures, the curing time of silicone sealant needs to be extended. In summer, it only takes one or two days to dry. In winter, it may take three days or even longer.

In addition, humidity also has a great impact on one-component silicone sealant. When there is little moisture in the air, the curing reaction of silicone sealant will be greatly inhibited.

2. Why does the adhesiveness of the same adhesive deteriorate?

As the temperature decreases, the activity of the adhesive additives in the silicone adhesive system decreases, which greatly affects the adhesiveness of the silicone adhesive. In addition, when the temperature is too low, there may be imperceptible fog or frost on the surface of the substrate, which affects the adhesion between the sealant and the substrate.

3. Why is there no problem during construction, but after a period of construction, a large number of bubbles and cracks appear in the colloid?

These problems usually occur when the silicone sealant is not fully cured and are caused by changes in width or movement of the seams.

In autumn and winter, the temperature difference between day and night is large, and the plates expand and contract due to temperature changes. Uncured silicone sealant is squeezed or stretched by the plates, which can easily cause cracks, "bulging", "cavities" and other problems. The "cavity" is what is called a large number of bubbles. Coupled with the low temperature and low humidity, the curing speed of silicone sealant slows down and the curing time becomes longer, which greatly increases the risk of silicone sealant cracking, "bulging", "cavities" and other risks.

4. How to reduce the environmental impact on silicone sealant during winter construction?

(1) Recommended usage conditions for one-component silicone sealant: temperature 5~40℃, relative humidity 40~80%. When the temperature is low, extend the curing time of silicone sealant.

(2) In response to this sudden drop in temperature and relatively low humidity, in a large-scale production environment, it is recommended to add small solar lights and humidifiers. In the absence of small solar lights and humidifiers, it is recommended to add a few more basins of water to the construction site. If construction is carried out indoors, if possible, it is recommended to increase the temperature and humidity of the environment through air conditioners, humidifiers and other equipment to increase the curing speed of the silicone sealant.

(3) If construction must be carried out under low temperature conditions, it is recommended to conduct a small-scale sealant test before construction, and then carry out large-scale construction after confirming that the bonding is good and there are no problems with the appearance.