What problems will structural sealants encounter in winter?

1. Slow curing

The first problem that the sudden drop in ambient temperature brings to the silicone structural sealant is that it feels cured during the application process, and the silicone structure is dense.

The curing process of silicone sealant is a chemical reaction process, and the temperature and humidity of the environment have a certain influence on its curing speed. For one-component silicone structural sealants, the higher the temperature and humidity, the faster the curing speed will be. After the winter, the temperature drops sharply, and at the same time, with the low humidity, the curing reaction of the structural sealant is affected, so the curing of the structural sealant is slow. Under normal circumstances, when the temperature is lower than 15 ℃, the phenomenon of slow curing of structural sealant is more obvious.

Solution: If the user wants to construct in a low temperature environment, it is recommended to conduct a small-area silicone sealant test before use, and conduct a peel adhesion test to confirm that the structural sealant can be cured, the adhesion is good, and the appearance is no problem. area used. However, when the ambient temperature is as low as 4°C, the construction of structural sealant is not recommended.

The sealant is glued using the temperature and humidity of the environment.


2. Bonding problems

With the decrease of temperature and humidity and the slow curing, there is also the problem of bonding between the structural sealant and the substrate. The general requirements for the use of silicone structural sealant products are: a clean environment with a temperature of 10°C to 40°C and a relative humidity of 40% to 80%. Exceeding the above minimum temperature requirements, the bonding speed is slowed down, and the time to fully bond to the substrate is prolonged. At the same time, when the temperature is too low, the wettability of the adhesive and the surface of the substrate decreases, and there may be indiscernible fog or frost on the surface of the substrate, which affects the adhesion between the structural sealant and the substrate.

Solution: When the minimum construction temperature of the structural sealant is 10 °C, the structural sealant is bonded to the substrate in the actual situation. Adhesion test should be done in low temperature construction environment to confirm good adhesion before construction. Factory injection of structural structural sealant can also speed up the curing of structural sealant by increasing the temperature and humidity of the environment in which the structural sealant is used, and at the same time, it is necessary to appropriately extend the curing time.


3. Increase viscosity

Structural sealants will gradually thicken and become less fluid as the temperature decreases. For two-component structural sealants, structural sealants increasing viscosity will increase the pressure of the glue machine and reduce the extrusion of the structural sealant. For one-component structural sealants, the structural sealant thickens, the increased pressure of the glue gun to extrude the structural sealant can be time-consuming and laborious for manual operations.

Solution: If there is no effect on the construction efficiency, low temperature thickening is a normal phenomenon, and no improvement measures are required.

If the construction effect, it is possible to consider increasing the operating temperature of the structural sealant or adopt some auxiliary heating measures, such as storing the structural sealant in a heating room or an air-conditioned room in advance, installing a heater for heating in the gluing workshop, and increasing the

Post time: Oct-24-2022