& nbsp; & nbsp; There are many types of building sealants, including silicone, polyurethane, polysulfide, acrylic acid, butyl, asphalt, and oil-based resin modified products. At present, the main building sealants used in China are silicone, polysulfide, and polyurethane room temperature curing elastic sealants, with silicone sealant being the most widely used. It is particularly important to choose professional and targeted building sealants correctly and control their construction quality.
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  & nbsp; & nbsp; Selection of building sealant

  & nbsp; & nbsp; How to choose sealant is key, and the application of building sealing mainly depends on its performance characteristics< br />


  & nbsp; & nbsp; 1. Concrete bonding

  & nbsp; & nbsp; The PC boards commonly used in the market are mostly concrete boards, so building sealants should have good adhesion to concrete. Due to the inherent characteristics of concrete, ordinary sealant is not easily adhered to its surface. When selecting building sealant, consideration should be given to whether concrete is an alkaline porous material and whether the release agent used during demolding remains on the surface of the PC board< br />


  & nbsp; & nbsp; 2. Seam displacement

  & nbsp; & nbsp; When selecting sealant, its mechanical properties are also important. When designing, the displacement of the joint should be considered to determine the joint width, so that the deformation of the sealant is within the maximum allowable range. For concrete joints of 10-35mm, it is generally required that the sealant has good displacement ability and elastic recovery rate to adapt to joint displacement< br />


  & nbsp; & nbsp; 3. Weather resistance

  & nbsp; & nbsp; The weather resistance of building sealant will affect its service life, and due to the specific molecular structure of silicone sealant, even under the highest energy of ultraviolet radiation, it is not enough to damage its structure, ensuring that silicone sealant has good UV resistance performance, giving it a significant advantage in weather resistance.
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  & nbsp; & nbsp; Construction technology of building sealant



  & nbsp; & nbsp; 1. Pre construction test

  & nbsp; & nbsp; Building sealant should undergo bonding performance and compatibility tests before construction to avoid delays in the project schedule and waste of materials and labor caused by cutting or rework after construction. Among them, the bonding performance test is to check whether the silicone adhesive used can form a good bond with the substrate; Compatibility test is to check whether the materials used in construction will have adverse effects on the sealant and affect its service life< br />


  & nbsp; & nbsp; 2. Construction process



  & nbsp; & nbsp; Seam preparation→ Cleaning of adhesive surface→ (If necessary, apply primer)→ Adhesive bonding→ Trim the adhesive surface and remove the protective tape; Curing and solidification (3-5 days in summer and 5-7 days in winter)< br />


  & nbsp; & nbsp; 3. Frequently Asked Questions



  & nbsp; (1) Not bonded to the substrate



  & nbsp; & nbsp; The main reasons are that no bonding test was conducted before construction, the curing temperature was too low, and the relative humidity was too high. During construction, the curing temperature should be increased, the curing time extended, the substrate surface treated, or the sealant replaced< br />


  & nbsp; (2) Slow curing speed



  & nbsp; & nbsp; The main reasons are low environmental temperature and humidity, narrow and deep glue joints, expired sealant, etc. During construction, the maintenance temperature and humidity should be increased, and two or double-sided gluing should be carried out, and the sealant should be replaced< br />


  & nbsp; (3) Generate bubbles



  & nbsp; & nbsp; The main reasons are that air is trapped during glue injection, moisture enters the glue seam, and the substrate reacts with certain sealants. During construction, the adhesive should be evenly, continuously, and fully filled into the interface, and the interface and accessory materials must be dry< br />


  & nbsp; (4) Drumming



  & nbsp; & nbsp; The main reasons are the large size and expansion coefficient of the plate, which leads to joint deformation, large temperature difference between day and night, and low environmental humidity. During construction, sealant with relatively fast curing speed should be selected, and appropriate shading measures should be taken to reduce panel temperature< br />


  & nbsp; (5) Cracking and water leakage



  & nbsp; & nbsp; The main reasons are narrow seams, inadequate sealing, insufficient displacement ability of sealant, and too thin adhesive thickness. During construction, the joints should be designed according to the specifications, and sealant with good displacement capacity should be selected. Construction should be carried out according to the operating specifications to ensure the thickness of the sealant and avoid three sided bonding.
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  & nbsp; & nbsp; 4. Precautions



  & nbsp; (1) Thoroughly remove all loose particles and dust, ensuring that the construction surface is clean, dry, and free of grease and surface dirt such as release agents, curing films, hydrophobic agents, etc< br />


  & nbsp; (2) Construction should be carried out in a clean environment with a temperature of 4~40 ℃ and a relative humidity of 40%~80%, and should be stopped during rainy and snowy weather< br />


  & nbsp; (3) To prevent damage to the sealing adhesive when the joint expands, a suitable backing material should be inserted into the joint, and the width of the backing material should be greater than 25% of the joint width to control the thickness of the sealant application< br />


  & nbsp; (4) A diagonal cut should be made at the outer opening of the sealant can, and then an extrusion gun should be installed to squeeze the sealant into the joint pressure surface. The thickness and width of the sealant should be uniform and consistent, meeting the sealing requirements< br />


  & nbsp; (5) When used as an adhesive, it should be applied and sealed in a dot or bead like surface, and after the sealing is completedApply a 20% detergent solution to smooth the surface of the joint< br />


  & nbsp; (6) After the construction is completed, random inspections should be conducted on the construction siteEnsure good adhesion and no adverse reactions.