The temperature drops,the temperature difference between day and night is large,and the air becomes dry.When the silicone structural sealant is constructed in winter,the temperature and humidity of the environment are low,and the curing speed and bonding speed of the sealant will be affected.
1.Slow curing speed
The first problem that a sudden drop in ambient temperature brings to a silicone structural sealant is that it feels slow to cure during application.The curing process of silicone structural 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.In winter,the temperature drops sharply,and 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 glue 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 lower than 4°C,the construction of structural sealant is not recommended.If glue is applied in a qualified factory,it can be considered to increase the temperature and humidity of the environment where the structural sealant is used.
2.Structural sealant bonding problems
With the decrease of temperature and humidity,accompanied by slow curing,there is also the problem of bonding between structural sealant and substrate.The general requirements for the use of silicone structural sealant products are:a clean environment with a temperature of 4°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 temperature is lower than the minimum construction temperature of the structural sealant by 4°C,the adhesiveness test of the structural structural sealant bonding substrate in the actual low-temperature construction environment shall be performed,and the construction shall be conducted after confirming that the bonding is good.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.Structural sealant thickening
As the temperature decreases,the structural sealant will gradually thicken and become less fluid.For the two-component structural sealant,the thickening of the structural sealant will increase the pressure of the gluer and reduce the extrusion of the structural sealant.For one-component structural sealants,the structural sealant thickens,and the pressure of the glue gun to extrude the structural sealant increases,and manual operations may feel time-consuming and laborious.
Solution:If there is no effect on the construction efficiency,low temperature thickening is a normal phenomenon,and no improvement measures are required.If it has an impact on the construction efficiency,you can consider increasing the use temperature of the structural sealant or adopt some auxiliary heating measures,such as storing the structural sealant in the heating room or air-conditioning room in advance,installing heating and heating in the gluing workshop,and increasing the gluing environment temperature.Wait.In addition,you can choose suitable glue tools,such as manual glue guns with high thrust,pneumatic glue guns,electric glue guns,etc.
4.The weather-resistant sealant is bulging--uneven appearance
When the weather-resistant sealant is in a low temperature environment,the weather-resistant sealant is prone to bulging,the curing speed of the weather-resistant sealant becomes slower,and the time required for the surface to cure to a sufficient depth will be longer.Thermal expansion and cold contraction)are larger,the surface of the glue seam will be affected,and there will be uneven bulging.
Solution:If the relative deformation of the glue joint is too large due to low humidity or temperature difference,glue joint size,etc.,it is recommended to choose one or more of the following methods for construction:
1.Take appropriate shading measures,such as shielding the scaffolding with dust-proof nets,so that the panels are not directly exposed to sunlight,reduce the temperature of the panels,and reduce the deformation of joints caused by temperature differences.
2.Try to arrange construction around noon and avoid construction in the morning and evening.
3.Use the method of secondary glue(that is,if the first glue has a concave glue seam,it can be cured for 2 to 3 days,and after it has elasticity,a layer of glue is added on the surface).
One:How to store winter sealant?
The best storage temperature of silicone weather-resistant sealant is:0~27℃.If possible,it can be placed in an air-conditioned room with constant temperature and humidity.In addition,the construction temperature of weather-resistant sealant should not be lower than 4℃or exceed 40℃.
Two:Can the temperature be lower than four degrees and the relative humidity of 35%can be glued?
It is not recommended for users to construct glue because:
1.When the temperature is too low,the wettability between the adhesive and the substrate surface is reduced,and there may be indiscernible fog or frost on the surface of the substrate,which affects the adhesion between the sealant and the substrate.
2.Under low temperature conditions,the curing speed of silicone sealant is slower than normal.The seam changes before the sealant is cured can easily cause bulges or cracks on the surface of the sealant,affecting the appearance of the sealant.
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