How to choose silicone sealant for different construction parts?

Silicone sealant is a kind of polydimethylsiloxane as the main raw material, which can be easily extruded and used under most temperature conditions, and cured with moisture in the air to form an excellent, durable, high-modulus, high-elastic silicone sealant. Ketone rubber.

Silicone sealants can be divided into one-component, two-component, structural adhesives, weather-resistant adhesives, etc. Different silicone sealants should be selected for different construction parts:

1. Structural assembly parts.

The sealant used between the curtain wall panel and its supporting structure needs to bear a variety of loads and ensure long-term adhesion without falling off. It must meet the requirements of the national mandatory standard "Silicon Structural Sealant for Buildings" (GB16776) .

Especially in high-rise and super-high-rise curtain walls, large-panel glass curtain walls, curtain walls using laminated insulating glass, curtain walls in earthquake-resistant 9-degree fortification areas, and even in the combination of these situations, it is even more necessary to use silicone structures with high performance. sealant. Because the adhesive has high tensile strength and elongation at break, it can withstand larger loads with the same bond width.

2. The seams of building curtain walls.

The expansion joint between the building curtain wall panel and the panel needs to be filled with glue, and silicone weather-resistant sealant should be used at this time. Because this kind of environmental silicone sealant needs to bear the displacement caused by wind load, dynamic load, and deformation caused by thermal expansion and contraction of the base material, the cohesiveness will not be damaged under tension or compression, and it is also relatively Good elastic recovery rate, after the displacement of the panel disappears, it can return to its original shape.

3. Stone panel parts.

Stone panel components must use a special stone silicone sealant. Because stone itself is a porous material, it is easily polluted and difficult to remove after contamination. General sealants contain non-reactive low-molecular substances such as plasticizers, which will migrate from the interior of the glue to the interior of the stone, and oil stains will appear on the surface of the stone and dust will be collected, causing stone pollution.

4. The top position of lighting.

Due to its own weight load, snow load, wind load, asymmetrical load, and material thermal expansion and contraction, the displacement of the daylighting roof is large and complex, not only horizontal displacement, but also shear displacement. Especially when polycarbonate board is used, due to its high coefficient of thermal expansion and contraction, it is six or seven times that of glass.

This requires the sealant to have low modulus, high displacement capacity, good material properties, and free expansion and contraction. It is best to use 50LM (50 low modulus level) silicone sealant, with a displacement capacity of plus or minus 50%. %. In addition, the glue used for the lighting roof also requires good transparency and elegant appearance.

5. The part between doors and windows.

The gap between the aluminum alloy and the glass of colored aluminum alloy doors and windows should be filled with special glue for aluminum alloy doors and windows. After fully cured, the glass can form an integral body with the aluminum alloy.

In the past, aluminum alloy doors and windows were often filled with polyacrylate, neoprene, polyurethane, etc., or the bond was easily damaged after being subjected to external force, or harmful gases were volatilized. There are no such disadvantages when using special glue for aluminum alloy doors and windows, and it can play a long-term sealing and waterproof role.