The raw materials for rubber expansion joints include EPDM rubber, nitrile rubber, chloroprene rubber, natural rubber, fluororubber, etc. The following will introduce the characteristics and advantages of each material.
1. EPDM expansion joint
Excellent comprehensive performance, with ozone resistance, weather resistance, high temperature resistance, low temperature resistance, chemical resistance, multiple solute resistance, and low relative density. The disadvantage is that it has a large expansion in general oils and lubricants, and is generally dark colored products. The temperature range of use is -60~+150 ℃, which is suitable for high temperature, high cold, coastal areas, areas with strong ultraviolet radiation, and mid to high-rise buildings. It has a wide range of applications and superior comprehensive performance.
2. Neoprene expansion joint
Compared with other rubbers, some of them have poorer performance, but the overall performance balance is good. They have excellent weather resistance, ozone resistance, heat aging resistance, oil and solvent resistance, good chemical resistance, excellent flame resistance, good adhesion, poor storage stability, and may experience hardening during storage, resulting in poor cold resistance. Relatively dense, generally black, suitable for oil and heat resistant environments, suitable for temperature ranges of -30~+120 ℃.
3. NBR expansion joint
The main characteristics are oil and solvent resistance, but it is not resistant to media such as ketones, lipids, and chlorinated hydrocarbons. Its elasticity and mechanical properties are good, but its disadvantages are easy aging and cracking in ozone and oxidation, poor cold resistance, and low temperature resistance. The temperature range for use is -30~+120 ℃
4. Fluorine rubber expansion joint
Fluorine rubber (FPM) is an organic elastomer formed by copolymerization of fluorinated monomers, characterized by high temperature resistance up to 300 ℃, acid and alkali resistance, oil resistance, radiation resistance, and good vacuum resistance; Electrical insulation, mechanical performance, chemical corrosion resistance, ozone resistance, and atmospheric aging resistance are all excellent, but the disadvantages are poor processability, expensive price, poor cold resistance, low elasticity and breathability, and the use temperature range is -20~+200 ℃
5. Natural rubber expansion joint
High elasticity, depending on the formula, the maximum elasticity can reach 80%. High elongation, up to over 1000%. The elastic modulus and shear modulus are low, much lower than some rigid substances such as steel. Due to natural rubber being crystalline rubber, its strength is very high in rubber, and it has good cold resistance. The glass transition temperature is -72 ℃. Low density, raw rubber density less than 1g/cm ^ 3. Not resistant to aging, but rubber can also be modified, such as chlorination and epoxidation, to improve heat and oil resistance. Poor oil resistance and chemical resistance (except for alkali). In concentrated hydrochloric acid, rubber will react with HCl to produce a protective film on the surface, preventing further reaction.
