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Views: 0 Author: Site Editor Publish Time: 2025-06-08 Origin: Site
In glass curtain wall projects, weatherproof sealants and silicone structural adhesives serve as two core sealing materials. Their performance differences directly impact building safety and longevity. This article provides a professional analysis from five dimensions: process characteristics, material composition, application scenarios, cost differences, and misuse risks.
Weatherproof Sealants: These utilize a single-component neutral curing process, forming an elastomer by absorbing moisture from the air at room temperature. Their key advantage is a movement capability of up to ±25% (the highest industry standard), allowing them to withstand expansion and contraction without cracking. Once cured, they create a flexible sealing layer that effectively absorbs thermal stress.
Silicone Structural Adhesives: Cured through a single-component moisture process, they form a high-modulus rubber with a tensile strength exceeding 30 MPa. Their rigid structure can support the weight of the curtain wall and withstand wind pressure, maintaining bond strength within a ±25% movement range. They are particularly suitable for rigid connections between metal frames and glass panels in concealed frame curtain walls.
Weatherproof Sealants: Based on polydimethylsiloxane, they incorporate weather-resistant fillers (like nano-scale titanium dioxide) and plasticizers. Their molecular structure provides excellent UV resistance, maintaining over 90% tensile strength after accelerated aging tests (1000 hours of xenon lamp exposure).
Silicone Structural Adhesives: Formulated with modified silicone resins and crosslinking agents to enhance bond strength. They achieve a Shore hardness of 60±5 and a break elongation of ≥200%, meeting the mechanical performance requirements outlined in the JGJ 102-2003 "Technical Specification for Glass Curtain Wall Engineering."
Sealing joints in glass curtain walls (joint width 6-50 mm)
Waterproofing for metal and stone curtain walls
Managing expansion joints in roof skylights
Example: Sealing joints in the exterior of the Shanghai Tower, using weatherproof sealants with an aging rate of less than 0.5%.
Structural bonding for fully or semi-concealed frame glass curtain walls
Secondary sealing for insulated glass
Anchoring connections for metal components
Example: The curtain wall system of the Burj Khalifa, where a single-point structural adhesive supports a load capacity of 2.5 kN.
The core cost difference: the raw material costs for structural adhesives are 30%-50% higher than those for weatherproof sealants, primarily due to the quantity of crosslinking agents and tackifying resins used.
Risk: High elastic modulus (≥0.4 MPa) can cause stress concentration at the joints, accelerating the cracking of the sealing layer.
Case: A commercial center experienced water leakage due to the misuse of structural adhesive, resulting in an additional maintenance cost of 2 million yuan.
Risk: Insufficient bond strength can lead to glass panel detachment under wind loads.
Weatherproof Sealant: Curing speed decreases by 50% at temperatures below 5°C, requiring heating assistance.
Structural Adhesive: Crystallization may occur below 0°C, negatively affecting bonding performance.
In glass curtain wall projects, the differentiated application of weatherproof sealants and silicone structural adhesives is crucial for ensuring building safety and functionality. Through precise material selection and standardized construction management, the overall lifecycle costs of curtain wall systems can be effectively reduced, achieving a win-win for building quality and economic benefits.