How to choose silicone structural adhesive

2023-08-05 22:54:56

Most silicone structural adhesives are named according to the application site, and corresponding products should also be selected according to the site when used.

Silicone sealant is a single component, neutral curing, structural bonding assembly designed for building curtain walls. It can be easily extruded and used under wide temperature conditions, relying on the moisture in the air to solidify into a relatively good, durable, high modulus, and high elasticity silicone rubber.

1. Structural assembly parts. The sealant used between the curtain wall panel and its supporting structure needs to withstand multiple loads and ensure long-term adhesion. It is not allowed to fall off and must meet the requirements of the mandatory standard "Silicone Structural Sealants for Building" (GB16776). It is even more necessary to use high-performance silicone structural sealant on high-rise and super high-rise curtain walls, large partition glass curtain walls, curtain walls using laminated insulating glass, curtain walls in areas with seismic resistance of 9 degrees, and even in a combination of these situations. This type of adhesive has high tensile strength and elongation at break, and can withstand relatively large loads with the same bonding width.

2. Joint parts of building curtain panels. The Expansion joint between the building curtain wall panel and the panel needs to be filled with glue. At this time, silicone weather resistant sealant should be used. It needs to bear the displacement caused by wind load, dynamic load, and deformation caused by Thermal expansion of the base material. Under tension or compression, the cohesiveness will not be damaged, and it also has a good elastic recovery rate. After the displacement of the panel disappears, it can return to the original state. You can refer to the standard "Joint Sealant for Curtain Wall Glass".

3 Stone panel parts. Stone panel components require the use of stone silicone sealant. Because stone itself is a porous material that is easily contaminated and difficult to remove after contamination. General sealants contain non reactive low molecular substances such as plasticizers that migrate from the inside of the adhesive to the interior of the stone, causing oil stains and dust absorption on the surface of the stone, resulting in stone pollution. This type of adhesive can be divided into two categories. One is the adhesive used for filling gaps in stone, which is used for sealing gaps between stone blocks. The second is the adhesive used for dry hanging stone, which is used for bonding between stone and metal hooks. In the past, rigid epoxy tree type stone dry hanging adhesive was commonly used, and when buildings vibrate, stress is also transmitted to the stone panel, making the stone easy to crack. The use of "elastic stone dry hanging adhesive" from Sibao Company can solve this problem.

4. The top part of the lighting system. Due to the weight load, snow load, wind load, asymmetric load and Thermal expansion of materials, the deflection of the daylighting roof is large and complex, including not only horizontal displacement, but also shear displacement. Especially when polycarbonate board is used, due to its high coefficient of Thermal expansion, it is 60% or 70% of that of glass. This requires the sealant to have low modulus, high displacement ability, good adaptability to materials, and the ability to freely expand and contract, making it easier to use 50LM (50 low modulus) silicone sealant. Its displacement capacity reaches plus or minus 50%. The adhesive used for daylighting also requires good transparency and aesthetics.

5. The area between doors and windows. The gap between the aluminum alloy and glass of colored aluminum alloy doors and windows should be filled with room temperature curable sealant. After solidification, a whole is formed between the glass and the aluminum alloy. In the past, filling with polyacrylate, chloroprene rubber, polyurethane, and other materials either easily damaged the bonding after external forces, or volatilized harmful gases. Silicone sealant has no such drawbacks and can play a sealing and waterproof role.