Classification and selection of building sealants
Silicone sealants have been widely used in construction fields such as curtain walls, doors and windows, hollow glass and interior decoration, playing a role of bonding and sealing. In the application process, we will come into contact with some product names of building silicone sealants, such as structural sealants, hollow sealants, weather-resistant sealants, door and window sealants, fire-proof sealants, etc. How are these sealant products classified? What role do they play? This issue of Baiyun Online article will introduce you to the classification and selection of building silicone sealants.
Most of the building silicone sealant products on the market are named according to their uses. In general, they can be roughly divided into the following five categories according to their uses: silicone structural sealants, silicone weather-resistant sealants, ordinary silicone sealants, two-layer silicone sealants for hollow glass, and special-purpose silicone sealants. Their characteristics are as follows:
1 Silicone structural sealant
Purpose: Mainly used for structural bonding of glass and aluminum sub-frame of concealed frame glass curtain wall or semi-concealed frame glass curtain wall
Features: Glue glass to aluminum sub-frame, withstand long-term (not less than 25 years) climate aging caused by ultraviolet rays, ozone, humidity, etc.; withstand loads caused by wind, gravity, temperature, etc., with high requirements for strength and aging resistance, and certain requirements for elasticity.
Precautions for using glue: Silicone structural sealant must be used for structural bonding of curtain walls, and it should also meet the requirements of curtain wall design. Do not use other types of sealants. It is recommended to use high-performance silicone structural sealant, which has higher safety.
2 Silicone weather-resistant sealant
Purpose: Used for sealing various curtain wall joints to ensure the air tightness, water tightness and other properties of the curtain wall.
Features: It needs to withstand large changes in joint width and outdoor ultraviolet rays, ozone, humidity, etc. for a long time. It has high requirements for elasticity (displacement capacity) and aging resistance, and does not require strength.
Glue precautions: The displacement capacity of silicone weatherproof sealant should meet the deformation of joints and meet the design requirements. Since the deformation of curtain wall joints is relatively large, it is recommended to use products with high displacement capacity. Products with high displacement capacity have better sealing durability, because the displacement of the glue joint does not reach the limit value of the product, which can better ensure the durability of curtain wall sealing.
3 Ordinary silicone sealant
Use: Used for door and window joints, exterior wall caulking, interior decoration sealing and other location sealing (see Figure 2).
Features: It can withstand relatively small changes in joint width, has certain displacement capacity requirements, and does not require strength. Outdoor joints have high requirements for aging resistance, and indoor joints have certain requirements for aging resistance.
Glue precautions: The products on the market are uneven, and a considerable number of products are filled with industrial white oil. Do not use silicone sealants filled with industrial white oil. Select sealant products that meet the GW index requirements in the national standard GB/T 14683-2017.
4 Two-layer silicone sealant for insulating glass
Purpose: Used for two-layer sealing of insulating glass to ensure the stability of the insulating glass structure (see Figure 3). According to the stress conditions, it is divided into two-layer sealant for structural insulating glass (mainly used for insulating glass of hidden frame and semi-hidden frame glass curtain walls) and two-layer sealant for non-structural insulating glass (mainly used for insulating glass of exposed frame curtain walls and doors and windows).
Features: high modulus, not too soft, high aging resistance requirements.
Precautions for using glue: Insulating glass of hidden frame and semi-hidden frame glass curtain walls must use silicone insulating glass structural sealant. Choose hollow sealant products with good brand reputation and guaranteed quality.
5 Special-purpose silicone sealants
Purpose: Used for joint sealing with special requirements, such as fireproof sealants for fireproof sealing of each layer of curtain wall projects, fireproof sealing of various doors and windows, indoor fireproof partitions, and fireproof sealing of interior decorations (see Figure 4); mildew-proof sealants are used for installation and waterproofing and mildew-proof sealing of various kitchen utensils and sanitary ware (see Figure 5).
Features: It must have certain special properties (such as mildew-proof, fireproof, etc.).
Precautions for using glue: For joint sealing with fireproof requirements, fireproof sealants must be used; for joint sealing with mildew-proof requirements, mildew-proof sealants must be used.
Figure 4: Curtain wall fireproof partition sealants must have fireproof properties
Figure 5: Kitchen and bathroom joint sealants must have mildew-proof properties
Silicone sealants for different purposes have their own different performance characteristics. According to different usage characteristics, users should correctly select construction silicone sealants. Using the wrong sealant may cause serious quality and safety accidents in the project. For example, weather-resistant sealant is used instead of structural sealant, door and window sealant is used instead of weather-resistant sealant, and fire-resistant sealant is not selected in places with fire protection requirements.
This article introduces in detail the classification and selection of building silicone sealants by use. I hope that users can fully understand this knowledge and choose the most suitable building silicone sealant in actual engineering applications! Baiyun Chemical can provide sealing system glue solutions and full-process services from all aspects and angles to help users choose high-quality and affordable building silicone sealant products!