Features and classification applications of silicone structural adhesives.
The glass building curtain wall organically integrates the use functions of the surrounding structure of the building such as wind, rain, lighting, heat preservation, heat insulation, cold protection, noise prevention, and air penetration with the decorative functions. It is a complex of architectural technology, architectural functions and architectural art. , Has been widely used in the world.
The development of glass building curtain wall is inseparable from the development of silicone structural adhesive. Silicone structural adhesive is widely used in the structural bonding and sealing of glass curtain walls due to its high and low temperature resistance, weathering resistance and ozone resistance, good adhesion to various substrates, and strong resistance to displacement. Since there is no other mechanical fixing device to support the glass panels in the curtain wall, the performance of the silicone structural adhesive plays an important role in the safety of the curtain wall.
◆Application of silicone structural adhesive
1. Used for structural or non-structural bonding assembly between metal and glass of glass curtain wall;
2. It can directly connect the glass and the surface of the metal component to form a single assembly component, which can meet the design requirements of the curtain wall with full or semi-hidden frame;
3. Structural bonding and sealing of insulating glass;
4. It is suitable for bonding and sealing of porous stone, laminated glass, insulating glass, mirror glass, coated glass, zinc, copper, and iron materials.
◆ Classification of silicone structural adhesives
1. Silicone structural sealant is divided into one-component, two-component, acid curing adhesive and neutral curing adhesive.
2. One-component silicone sealant can be directly applied to the bonding between aluminum and glass. It is hydrolyzed by absorbing moisture in the air, and the condensation reaction is solidified from the surface to the inside. It requires cleaning and construction in the glue room. The temperature should not be lower than 15°C or higher than 30°C, and the relative humidity should not be lower than 50%. , Otherwise it will affect the curing and reduce the strength of the adhesive layer.
3. One-component silicone glue is divided into acidic and neutral. When the acidic glue is cured, it will release acetic acid, which will corrode the film of the coated glass produced by the vacuum magnetic sputtering method for the hidden frame curtain wall. Therefore, it should be used. Sexual silicone structural adhesive.
4. The two-component glue is a neutral glue. Before use, an accelerator must be added to the base glue, and the aluminum and glass must be fully mixed and coated in a special glue machine for bonding and curing.
◆ Precautions for the operation of silicone structural adhesive
1. The glue maker should be maintained regularly to ensure that the glue maker can work normally. A butterfly test must be done before each startup to ensure that the structural glue is evenly mixed.
The butterfly test method is as follows: squeeze the mixed glue from the glue maker into the middle of the paper for 5-10 grams, fold the paper to flatten the glue. Open the paper to check the glue sample. The evenly mixed glue should have no different-color stripes. If the glue has different-colored stripes, it means that the glue is not uniform. Find the cause and use it after the problem is solved.
2. The problem of uneven mixing of structural adhesive has a great relationship with the glue dispenser, which will seriously affect the curing of structural adhesive and the strength after curing, and endanger the safe application of structural adhesive. In the process of using glue, you must ensure that the glue mixing machine is normal and use the structural glue.
◆ The difference between silicone structural adhesive and sealant
Silicone weatherproof sealant is mainly used for sealing and caulking between materials, while structural glue is mainly used for bonding, and the two are not used in the same place.
Silicone weather-resistant sealant can also be said to be a general-purpose adhesive, which is mainly resistant to extreme weather such as ultraviolet rays, acid rain, and snow. In addition to the characteristics of weather-resistant sealant, silicone structural adhesive also has stronger bonding properties than silicone weather-resistant sealant, which is mainly manifested in tear strength, elongation at break, tensile strength, and tensile strength. Mainly used in prestressed places. Structural adhesives are used for structural and non-structural assembly bonding of various curtain walls, while weather-resistant adhesives are mainly used for waterproofing and sealing the joints. The modulus, hardness, strength and price of structural rubber are higher than that of weather resistant rubber of the same grade, but the elasticity of weather resistant rubber is higher than structural rubber.
Silicone structural sealant and silicone weather-resistant sealant cannot be mixed, depending on where you use it. The use of structural adhesive for sealing is firstly costly, and secondly, it is not conducive to the displacement of the joint. Where structural adhesives should be used, weather-resistant adhesives must not be used.