First, what is the rubber shrinkage rate?
Rubber shrinkage refers to the proportion of rubber products in the vulcanization process after adding vulcanizing agent, which is an important physical parameter in the design and production process of rubber products. Because there will be shrinkage in the vulcanization process of rubber, it is necessary to consider the shrinkage rate of rubber when designing rubber products to ensure the accuracy and performance of the product size.
Second, different types of rubber shrinkage index
1. Styrene butadiene rubber (BR)
The shrinkage rate of styrene butadiene rubber is generally about 2%.
2. Neoprene rubber (CR)
The shrinkage rate of neoprene rubber is generally 1.5% to 3%.
3.Nitrile butadiene rubber (NBR)
The shrinkage rate of nitrile rubber is generally between 2% and 4%.
4. Hydrogenated nitrile butadiene rubber (HNBR)
The shrinkage rate of hydrogenated nitrile butadiene rubber is very small, generally within 1.5%.
5. Natural Rubber (NR)
The shrinkage rate of natural rubber is generally between 1% and 3%.
6. Butyl rubber (IIR)
The shrinkage rate of butyl rubber is generally 1.5% to 3.5%.
7. Acrylic Rubber (ACM)
The shrinkage rate of propylene rubber is generally between 2.5% and 3.5%.
8. Silicone Rubber (VMQ)
The shrinkage rate of silicone rubber is generally within 1%.
9. Polyurethane Rubber (PU)
The shrinkage rate of polyurethane rubber is generally between 0.5% and 2%.
Third, the effect of rubber shrinkage on rubber products
The shrinkage rate of rubber has a great impact on the dimensional accuracy and performance of rubber products, if the shrinkage rate is too large, it will lead to inaccurate product size, size shrinkage and other problems; If the shrinkage rate is too small, it will lead to surface roughness, surface cracking, wear resistance and other problems. Therefore, in the design and production of rubber products, it is necessary to choose the appropriate rubber material and the corresponding shrinkage index according to the specific situation.