Silicone rubber possesses excellent high and low-temperature resistance, aging resistance, outstanding dielectric properties, and physiological inertness. It has become one of the indispensable high-elasticity materials in modern science and technology. The main drawback of silicone rubber is its strength properties, particularly its low tear strength, which limits its applications. Therefore, the necessity to improve the strength and tear resistance of silicone rubber is crucial for expanding its application range.
The Difference Between High Tear Strength Silicone and Ordinary Silicone Rubber
Ordinary Silicone Rubber Material is mainly composed of: raw rubber, reinforcing fillers (commonly used structure control agents), heat-resistant additives (commonly using iron oxide as a crosslinking peroxide), and peroxides to prevent the interaction between silica and raw rubber.
High Tear Strength Silicone is made from high-strength raw rubber, modified fumed silica, and other auxiliary materials. Compared to the fumed silica used in ordinary fumed silicone rubber, modified fumed silica has unique functional groups and imparts higher tear strength after mixing and molding.
What effects do fillers, control agents, etc., have on improving tear resistance?
1. The influence of vinyl-containing organic compounds on tear resistance: To achieve high tear resistance, the amount of vinyl silicone oil should be 3-5 parts. After aging at 200°C for 72 hours, the rubber still exhibits excellent tear resistance; excessive dosage reduces aging performance and is economically unreasonable.
2. The dosage of carbon black has a significant impact on tear resistance. As the carbon black dosage changes, the amount of hydroxyl silicone oil used as a structure control agent also changes; vulcanization hardness and compression set increase with the increase in carbon black dosage.
3. Through experiments with different types and dosages of peroxides, it can be concluded that commonly used peroxides can produce high tear strength silicone rubber within an appropriate dosage range.
4. The influence of structure control agents: Siloxanes are used as structure control agents. Experiments have proven that regardless of which siloxane is used, high tear resistance can be achieved.
