Sealing strip performance mainly consists of some material properties related to life and functional properties related to use.In general, material properties are expressed by coach properties and usability by finished product properties.
The service life of the product is determined by the material properties because of the harsh service conditions of the sealing strip.In particular, the requirements of the climate is extremely harsh, in order to ensure the normal operation of the sealing strip in these conditions, so the coach's specifications and performance usually have the following items:
Hardness, tensile strength, elongation at break.
The basic performance requirements of these materials, usually for its supply state and hot air two groups of performance requirements.According to the service state, the service temperature range of the car is -40℃-70℃.The aging temperature of hot air is generally 70℃.
Compression permanent deformation
This is because the sealing strip is made use of the high elasticity of its material and the coupling between the body - based pressure to achieve the medium of the sealing strip.Rubber in the compression state of physical and chemical changes, when the compression disappeared.These changes prevent the material from returning to its original state, resulting in compression permanent deformation, so compression permanent deformation is an important index to measure the performance of sealing strip material.
Resistant to ozone aging and air aging
This is because the working environment of the car is in all-weather condition for a long time (rain, snow, wind, frost and sun), so the requirements of the sealing strip in a variety of environments to maintain certain performance requirements and necessary service life, must require all materials with good aging resistance.
Resistance to paint
This is due to the sealing strip directly installed in the car body, vulcanization of the internal components outside contact with the car paint.In direct contact with the car body paint board, the components in the paint in a variety of environments free material will interact with the seal strip, accelerate the aging, reduce its performance, so paint resistance is an important routine performance of the seal strip.
The high temperature performance
Due to the sealing strip operating temperature range of -40℃-70℃ (engine room may reach 120℃).Epdm rubber variety (classified by propylene content), and its vulcanized rubber properties directly affect the low temperature elasticity of the seal strip, in order to maintain good elasticity at low temperature, this property is often used as a routine property.
The finished product performance
According to the usage function and the installation request, people proposed a series of finished product routine performance items.
(1) compression load (extrusion pressure)
(2) compression permanent deformation
(3) climate resistance to aging
(4) coating performance (wear resistance)
5. Flocking resistance and adhesion
6. The insertion force
7. Angle properties, etc
2. Installation performance
Compression load, door frame strip, trunk strip, head road, engine cover strip, etc.Take door frame bar as an example now, when it asks to close the door, close the door force is lesser, namely compress load to jump over lesser had better.But the door is required to close the sealing strip has a certain elasticity, in order to maintain a good seal, that is, the larger the compression load, the better, so to solve this contradiction, compression load should have an appropriate range value.Values on the basis of experience through the CAD/CAE and limited element analysis to obtain the appropriate range value, reduce the closing force, a kind of method, can be in the proper number of sealing strip with a vent, closed drainage of bubble tube in time in the air, but the size of the vent and the number doesn't affect the sealing strip of a type: another way is to contact part with a certain thickness of coating on the surface to reduce friction.Coating type: PU and silicone oil, which used to be organic solvent, are now water-soluble (environmental protection).
Inserting and pulling force: for the sealing strip with clamping part of the structure, the size of inserting and pulling force is also a prominent contradiction, that is, the assembly is expected to be easy, but also hope to use firmly, that is, the insertion force is expected to be small and the pulling force is large.