There are many kinds of EPDM sealant strips for trains. The specific analysis is as follows:

1. EPDM rubber

Ethylene propylene diene monomer (EPDM) is polymerized by adding a small amount of non conjugated dienes to ethylene and propylene monomers. The characteristic of its structure is that there is no unsaturated double bond in the main chain of the polymer molecule, but there is unsaturated double bond in the branch chain. Therefore, it has excellent weather resistance, heat resistance, ozone resistance, UV resistance, good processability and low compression permanent deformation. It is the preferred material for the production of sealing strips. At present, the vast majority of automotive sealing strip materials use EPDM as the main raw material.

According to the different parts and functions of the sealing strip, in practical application, vulcanization, protection, reinforcement, operation system materials and special imparting materials (such as colorant and foaming agent) are added to EPDM materials to form dense rubber (including black rubber and color rubber) and sponge rubber.

2. Polyvinyl chloride

Polyvinyl chloride (PVC) is a traditional general-purpose plastic. Its aging resistance and rubber feel are greatly improved by modification. However, due to its poor elasticity, it is mainly used as the clamping part material for inner and outer side strips and some sealing strips. PVC is also commonly used as door frame sealing strip on trucks and agricultural vehicles, and it is often combined with EPDM as light color auxiliary material on cars.

3. Thermoplastic elastomer

Thermoplastic elastomer material (tpe/tpv) is a material developed in recent years. Its structural characteristics are composed of plastic and rubber, so it has the characteristics of both plastic and rubber to a certain extent. It does not need vulcanization in the processing process, so it is easy to achieve accurate section control. At the same time, the material can be reused under certain conditions, with little environmental pollution. Therefore, it is very concerned by the designers of the whole vehicle and the sealing system.