Commonly used rubber shrinkage and its influencing factors

First, commonly used rubber shrinkage rate

When rubber is heated or cooled, it shrinks or expands, which is the shrinkage rate of rubber. Generally speaking, the shrinkage rate of rubber depends on the type, quality, hardness, thickness, shape and other factors of the rubber material. The following are some commonly used rubber shrinkage rates:

1. Ordinary butyl rubber: 3% ~ 10%

2. Neoprene rubber: 1.5% ~ 5%

3. Silicone rubber: 2% ~ 4%

4. Fluorine rubber: 1.5% ~ 4%

It should be noted that the above data is only a reference value, and the actual production should be adjusted according to the specific situation.

Second, the factors affecting the shrinkage rate of rubber

1. Temperature: Generally speaking, the shrinkage rate of rubber increases with the increase of temperature. This is because as the temperature rises, the molecular thermal movement inside the rubber material intensifies, resulting in the destruction of the chain structure, which causes the rubber to shrink.

2. Pressure: At a certain temperature, the shrinkage rate of rubber is also related to pressure. In general, the greater the pressure, the smaller the shrinkage rate.

3. Hardness: Different hardness of rubber, its shrinkage rate is also different. Generally speaking, the harder the rubber, the smaller the shrinkage rate.

4. Thickness and shape: the shrinkage rate of rubber is also related to its thickness and shape. In general, the shrinkage rate of rubber with larger thickness and complex shape is also larger.

Three, how to control the rubber shrinkage rate

When making rubber products, it is very important to control the shrinkage rate of rubber. Here are some ways to control shrinkage:

1. Reasonably design the mold shape and adopt appropriate process parameters.

2. Control the process parameters such as temperature and pressure, and adjust the shrinkage rate according to the actual situation.

3. Choose the right rubber material.

4. In the mold assembly, injection molding, demoulding and other links, we need to strictly grasp every detail to ensure that there is no big error in the production process.

In short, the shrinkage rate of rubber is one of the physical properties that must be considered when making rubber products, which has an impact on the dimensional accuracy and production process of the product. In the production process, adjustments need to be made according to the specific situation to ensure the quality of the product.