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

1. EPDM rubber

Ethylene propylene diene monomer (EPDM) is polymerized by ethylene and propylene monomer and a small amount of non conjugated diene. The characteristic of its structure is that there is no unsaturated double bond on the main chain of the polymer molecule, but unsaturated double bond is introduced on the branch chain. Therefore, it has excellent weather resistance, heat resistance, ozone resistance, ultraviolet resistance, good processing performance and low compression permanent deformation, and is the preferred material for producing sealing strips. At present, most of the automotive sealing strip materials are made of 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 the EPDM material 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 feeling are greatly improved by modification. However, due to its poor elasticity, it is mainly used as the clamping part material of 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 used as light color auxiliary material in combination with EPDM 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, and it is easy to achieve accurate section control. At the same time, the material can be reused under certain conditions and has little environmental pollution. Therefore, it is very concerned by the designers of the whole vehicle and the sealing system.