What are the causes of bad vulcanization of silicone rubber products?

Date:29-06-2020
Abstract:

In the production process of silicone rubber products, […]

In the production process of silicone rubber products, we often see the "poor vulcanization" of the products. We call it "unfamiliar". This is a very serious defect for our silicone rubber products. If it reaches customers, the consequences will be unimaginable. , So what are the factors that lead to poor product vulcanization?

First: Improper ratio of vulcanizing agent. Everyone knows that the raw material we purchased is raw rubber and we need to add vulcanizing agent masterbatch, etc. These are strict requirements according to the material formula, which needs to be accurately weighed and weighed according to the formula The required proportion is added. If the ratio is not correct, it will affect the material properties and lead to poor vulcanization of the product.

Second: Uneven distribution of vulcanizing agent mixing. If vulcanizing agent is added during mixing, if the distribution area is too concentrated or too dispersed, it will also lead to poor vulcanization in subsequent production.

Third: The vulcanization temperature is too high or too low. When molding, the surface temperature of the mold should be set to an appropriate temperature according to the different characteristics of the material, and the temperature of the mold should be evenly distributed without local temperature being too high or too low. Generally, the maximum temperature of the upper and lower molds cannot be 5 degrees Celsius.

Fourth: Insufficient vulcanization time. Each material has a vulcanization time that must be met to complete vulcanization. The vulcanization time of the same material formula will be different. Some manufacturers may reduce the vulcanization time during molding in order to pursue production capacity. , The appearance may not be seen when it is first produced, but in fact the product is not fully vulcanized and the actual performance of the material is not reached, such products will have relatively poor physical properties, such as the aging resistance and tear resistance of the product and ect.