How do silicone sealing gaskets effectively resist UV rays and extend their service life?
Publish Time: 2025-09-18
In applications exposed to sunlight for extended periods, such as outdoor equipment, automotive components, building curtain walls, solar systems, and communication base stations, one of the greatest challenges facing sealing materials is UV radiation. Intense sunlight not only generates high temperatures but also contains high-energy UV waves, which can damage the molecular structure of many organic materials, causing them to age, become brittle, crack, and even fail. However, silicone sealing gaskets can operate stably and long-term in such harsh environments, demonstrating weather resistance far exceeding that of ordinary rubber. This is due to the combined effects of their unique material properties and structural design.1. Intrinsic Molecular Structure Provides Natural UV ResistanceUnlike traditional carbon-chain polymers, silicone's core skeleton is composed of an extremely stable chemical structure. This structure is highly immune to high-energy UV rays. UV energy is typically sufficient to break carbon-carbon or carbon-hydrogen bonds, triggering free radical reactions within the material, leading to chain breakage or excessive cross-linking, manifesting as surface chalking, cracking, and loss of elasticity. Silicone's main chain structure absorbs UV light very weakly, effectively preventing it from triggering a destructive reaction. This means that even after prolonged exposure to intense sunlight, its internal structure remains intact, preventing rapid degradation due to photochemical degradation. This inherent advantage gives silicone excellent UV resistance, eliminating the need for extensive additives to achieve long-term stability.2. No reliance on easily degradable chemical additivesMany common rubber materials require chemical additives such as UV absorbers or antioxidants to provide UV resistance. While these additives provide short-term protection, they are gradually consumed, evaporate, or migrate from the material surface over time, reducing their effectiveness. Once the additives are depleted, the material rapidly degrades. In contrast, the UV resistance of silicone sealing gaskets stems primarily from their inherent structure, rather than from external additives. This not only reduces formulation complexity but also prevents a sudden drop in performance due to additive deterioration. As a result, silicone gaskets maintain stable physical properties throughout their service life, without experiencing sudden embrittlement or accelerated aging.3. Excellent Heat and Ozone Resistance for Synergistic ProtectionUltraviolet rays are often accompanied by high temperatures, which accelerate material aging. Silicone sealing gaskets offer excellent high and low temperature resistance, maintaining elasticity over a wide temperature range of -60°C to 200°C and beyond. This thermal stability prevents them from softening, flowing, or thermally degrading under intense sunlight. Furthermore, ultraviolet rays in sunlight convert oxygen in the air into ozone, which is highly corrosive to many rubber materials and can easily cause "ozone cracking." Silicone materials are naturally inert to ozone and will not crack even in high-concentration ozone environments. This ozone resistance complements UV resistance, further enhancing their durability in challenging outdoor environments.4. Surface Stability, Resistant to Chalking or DiscolorationMany sealing materials experience surface chalking, color fading, or cracking after prolonged exposure to UV rays. However, silicone sealing gaskets typically exhibit only minor color changes (such as darkening) after prolonged sunlight exposure, without surface peeling or structural damage. Its surface remains smooth and dense, effectively blocking the intrusion of moisture, dust, and gas, ensuring that the sealing function is not compromised by appearance changes.5. Maintaining Elasticity and Sealing Strength Even After Long-Term UseThe core function of a sealing gasket is to provide a continuous and reliable seal. If the material becomes hard and brittle due to UV exposure, and its compression set increases, the sealing strength will decrease and leakage will occur. Silicone sealing gaskets have performed exceptionally well in long-term UV aging tests, maintaining excellent resilience and compressive stress relaxation properties even after thousands of hours of UV-accelerated aging. This means that they can still "adhere" to the sealing surface and maintain effective pressure even after prolonged use, ensuring safe equipment operation.The key to silicone sealing gaskets' effective UV resistance and significantly extended service life lies in their unique material nature—a structurally stable polymer system that is insensitive to high-energy UV light. It does not rely on readily depleted additives and offers both high-temperature and ozone resistance and excellent elasticity retention, making it an ideal sealing solution for outdoor, high-altitude, and tropical environments with strong UV rays.
