Cold temperature makes people trembling, arctic climate makes sealant application difficult. Inappropriate construction methods and product application not only prevent full performance of product, but also make some difficulties for construction. Now let’s go to know about the application of sealants in extreme cold area.Best silicone sealant.
1.General application situation of door, window and curtain wall sealants.
Silicone sealant is more often used when it comes to door, window and curtain wall sealant. Silicone sealant exhibits excellent resistance to both high and low temperature, it still maintains good performance with low temperature and humidity. In real construction, water-based acrylic sealant and rubber sealant are also proper if the requirement for sealant properties is lower. But in extreme cold area, performances of water-based acrylic sealant and rubber sealant are not very good, they are easily brittle, aging and cracking in low temperature situation.
There are some limits for the construction of sealants in extreme cold area, the environment requirements for application of general silicone sealants are: temperature 5℃~45℃, clean environment with relative humidity 40%~80%. There will be some potential accidents when temperature of construction environment and substrate is lower than 5℃.
Silicone sealants are divided into single and two component, and construction of two component sealants are usually indoor for the easy control of environment condition. All of silicone sealants are single component when used in construction of door, window and curtain wall projects. Only when they react with moisture in air, they just can cure. The higher temperature and humidity are, the faster reaction speed is.
2.Influences of low temperature and humidity to sealant construction.
In general situation, construction for sealants is not suggested in the environment of low temperature and humidity.
Low temperature and humidity make it difficult for sealant construction. There are some reasons:
- When temperature is too low, wettability between sealant and surface of substrate will reduce. And there may be invisible fog or frost, which will influence the adhesion between sealant and substrate.
- In low temperature, curing speed of silicone sealant is slower than that is in general condition. If joints change before the absolute curing of sealant, it will make the surface of sealant bulging or cracking and influence the appearance of sealant.
3.Is there any guarantee of sealant after construction with low temperature?
In general situation, performance of sealant after construction is guaranteed good in low temperature. Considering the performance of sealant in low temperature when product design, relevant test about low temperature is done while product testing.
In <construction structural silicone sealant> GB 16776-2005, there is a tensile adhesion test in -30℃, requiring that tensile strength is not less than 0.45MPA and area of adhesive bond loss is no more than 5%. And there is a adhesion test after cold drawn and hot pressed in both <construction silicone sealant> GB/T 14683-2003 and <sealants for joint glass curtain wall> JC/T 881-2001, requiring that after freezing at -20℃, sealant must have no adhesion bond loss when do some stretch under cyclic movement. Low temperature flexibility test of sealant is required in <glazing elastic sealants for building> JC/T 485, sealant of grade 1 should be not cracking, layered or adhesive damaging.
4.In order to meet tight deadlines, how does construction carry on with low temperature?
If projects have to meet tight deadlines and result in construction with low temperature, it is suggested to applicate on a small area and do adhesion test, make sure that adhesion is good and there is no problem about appearance before applying into large scale areas. In the process of application in large scale area, cutting silicone sealant to check adhesion should be more frequent on site. And quality control should be recorded to ensure the quality of construction.
5.Are there any methods to reduce influences of low temperature for silicone sealant while constructing?
As to cold area, choosing premium silicone sealant could just meet the requirement for sealant adhesive properties in low temperature. In case of catching the time limit in low temperature, in order to reduce adverse effects of silicone sealant from construction in low temperature, there are some suggestions below:
- For processing of glass curtain wall units and sashes of windows and doors, because of construction indoor, when environment temperature is low, humidity and temperature could be adjusted by air conditioning, heating, humidifier and etc. to make sure normal curing of silicone sealant.
- For curtain wall panel joint sealing and sealing between door, window and wall, construction should start when the temperature is highest during the day as far as possible.
