Characteristics of Adhesives with Different Compositions

I. Epoxy Resin Adhesives
1. Epoxy resins are characterized by high mechanical strength, a dense chemical structure, and strong cohesive forces; consequently, epoxy adhesives offer excellent bonding performance.
2. Epoxy resins exhibit low volumetric shrinkage and a low coefficient of linear expansion, resulting in minimal internal stress and excellent processing characteristics.
3. Epoxy resins generate virtually no low-molecular-weight volatiles during curing, ensuring superior electrical properties.
4. Free from impurities such as salts and alkalis, epoxy resins are highly stable and resistant to degradation.
5. However, epoxy resins have moderate heat resistance and poor adhesion to low-polarity materials (such as PP and fluoroplastics); surface activation treatment is required for such applications.
II. Polyurethane Adhesives
1. Polyurethanes feature a wide hardness range, high mechanical strength, and excellent wear and impact resistance—properties that are imparted to polyurethane adhesives.
2. Polyurethane adhesives maintain excellent flexibility and elasticity at low temperatures.
3. Polyurethane adhesives offer outstanding weather, oil, and aging resistance.
4. However, due to the specific chemical structure of polyurethane, these adhesives are unsuitable for use in high-temperature or high-humidity environments.

Ⅲ. Silicone
Silicone is currently the most widely used adhesive on the market.
1. Silicone offers excellent electrical properties, a wide operating temperature range, good flexibility, and low stress.
2. Silicone does not generate heat during curing; it has low toxicity and minimal shrinkage after curing, making it highly popular among workers who use adhesives.
3. Silicone is chemically stable and corrosion-resistant.