Material Types for Automotive Seals

PVC (Polyvinyl Chloride)

Polyvinyl Chloride (PVC) is a traditional general-purpose plastic. By modifying it, its aging resistance and rubber-like properties are greatly improved. However, due to its limited elasticity, it is primarily used as the inner and outer strips, as well as the clamping parts of seals. In trucks and agricultural vehicles, PVC is commonly used for the body door frame seals, while in passenger cars, it is often combined with EPDM to serve as light-colored materials.

2. Ethylene Propylene Diene Monomer (EPDM) rubber

EPDM rubber is synthesized by polymerizing ethylene, propylene monomers, and a small amount of non-conjugated diene. Its unique structure features no unsaturated double bonds in the polymer's main chain, while unsaturated double bonds are introduced into the branches. This results in excellent weather resistance, heat resistance, ozone resistance, UV resistance, and good processing properties, as well as low compression set, making it suitable for sealing strip production. Currently, the majority of automotive sealing strip materials use EPDM as the primary raw material.

Based on the varying parts and functions of seals, in practical applications, vulcanization, protective, reinforcing, operational system materials, and special additives (such as colorants and foaming agents) are added to EPDM materials. This creates dense adhesives (including black and colored adhesives) and sponge-like gels.

3. Thermoplastic Elastomers

Thermoplastic elastomer materials (TPE/TPV) have emerged as a material of recent development, characterized by their composition of plastic and rubber phases, thus combining certain features of both. This allows for precise cross-sectional control during processing without the need for vulcanization. Moreover, the material can be recycled under certain conditions, making it environmentally friendly and highly sought after by vehicle and sealing system designers. However, due to its lower elasticity and significant permanent deformation upon compression, as well as the still immature technology in manufacturing foam bodies and higher costs, its usage is significantly limited. Currently, it is primarily used in the production of car window side strips and window guides. As TPE manufacturing technology continues to improve and mature, its application scope is expected to expand further.