Phenyl silicone rubber exhibits excellent low-temperature resistance, superior weatherability, and stable mechanical properties in architectural glass sealant applications, making it particularly suitable for building sealing needs under extreme climatic conditions.
I. Basic Characteristics and Classification of Phenyl Silicone Rubber
Chemical Structure and Classification
Phenyl silicone rubber is a type of methyl vinyl phenyl silicone rubber, with a main chain composed of alternating silicon and oxygen atoms, and side chains containing phenyl groups. Based on the phenyl content, it can be classified into:
Low-phenyl silicone rubber (phenyl content 5-10 mol%): Offers the best low-temperature resistance, with a hardening temperature down to -115℃, maintaining flexibility and elasticity even at -100℃.
Medium-phenyl silicone rubber (phenyl content 15-25 mol%): Possesses ablation resistance and is suitable for high-temperature environments.
High-phenyl silicone rubber (phenyl content 30-50 mol%): Exhibits excellent radiation resistance, capable of withstanding 2.58 × 10⁴ C/kg gamma ray radiation.
Key Performance Advantages
Wide Temperature Range Adaptability: Maintains excellent elasticity in the range of -100℃ to +70℃, with some products having a temperature range of -100℃ to 250℃.
Weatherability: Has good resistance to ultraviolet radiation, ozone, moisture, and various chemicals, and is not prone to aging or deterioration.
Low Compression Set: Maintains shape and dimensional stability after prolonged compression, suitable for applications requiring high sealing performance.
Excellent Electrical Insulation: Makes it an ideal insulating material for electronics, communication equipment, and other fields.

II. Application Advantages and Precautions
Core Advantages
Low-Temperature Resistance: In extremely cold regions, phenyl silicone rubber maintains elasticity at -100℃, far superior to ordinary silicone rubber (which typically maintains performance at -55℃).
Weatherability: Compared to EPDM rubber, phenyl silicone rubber has better ozone resistance and weather aging resistance, making its performance more reliable under special working conditions.
Elasticity and Resilience:  It is not easily deformed after being compressed or stretched by external force, and can return to its original shape after the external force is removed, unlike EPDM rubber... The sealant is prone to permanent deformation.
Tear Resistance: Phenyl silicone rubber has a tear strength of ≥32 KN/m, significantly higher than EPDM rubber (≤15 KN/m).
Construction Precautions
Environmental Conditions: The construction environment temperature should be maintained between 5℃ and 35℃, relative humidity between 40% and 80%, and wind speed ≤5.4 m/s (level 3 wind).
Substrate Preparation: Use the "two-step cleaning method," first wiping away dust with a dry cotton cloth, then wiping with a lint-free cloth dampened with isopropanol in the same direction.
Sealant Application Process: Hold the sealant gun at a 45° angle, maintaining a constant speed (approximately 150-200 mm/min) to ensure the sealant fills the entire joint.
Curing Time: The curing time of single-component silicone glass sealant increases with the thickness of the adhesive layer. For example, a 12mm thickness may require 3-4 days to fully cure.
Safety and Environmental Protection
Low VOC Formula: Modern phenyl silicone rubber sealants use a low VOC formula, reducing environmental pollution.
Carbon Neutral Certification: Some products offer project-specific carbon neutral certificates, complying with the PAS 2060 standard, supporting green building certification.
Safe Use: Ensure good ventilation during construction, avoid prolonged contact with skin, and wash hands thoroughly after construction.
The application of phenyl silicone rubber in architectural glass sealants represents the development direction of high-performance sealing materials, especially suitable for extreme climate conditions and demanding construction projects. By rationally selecting the phenyl content and construction process, the durability, sealing performance, and aesthetics of architectural glass systems can be significantly improved, providing a reliable protective barrier for modern buildings.