What Is The Reason For The Small Cracks On The Product When NBR Rubber Is Vulcanized?
Sep 11, 2022
One: return glue
1. (The remaining rubber is mixed with the new rubber after hot-melting, and the remaining rubber is called return rubber) The mixing is uneven when hot-melting with the new rubber, resulting in the degree of vulcanization. inconsistency, resulting in stratification
2. The compound or mold is contaminated with grease or other substances, causing stratification in the contaminated area
3. The release agent is sprayed too much, so that part of it penetrates into the rubber compound, causing delamination and cracking
4. Uneven mixing or blooming
5. The plasticity of the rubber is too poor
Two: Appropriately increase the number of thin passes
Three: If oil pollution occurs on the surface of the product, there is a possibility of cracking there. Therefore, the rubber material should be properly stored, and the mold should be cleaned before use.
Four: Except for the part where the mold sticks, other places can be left unpainted or less painted
Five: The rubber compound should be fully heat-smelted before use, which can partially eliminate the uneven mixing and blooming phenomenon. The heated compound is used immediately and cannot be parked for too long, otherwise, the blooming phenomenon may occur.
Six: For example, some fluororubbers have poor plasticity,
When the rubber compound is moulded in the form of sheets, blocks and strips, it is very difficult to fuse the films, blocks and strips at the normal vulcanization temperature, and delamination and cracking often occur. will be more serious. Precautionary measures: The hot refining should be sufficient, and the blanks similar to the products should be used for moulding, and the high ones should be used as much as possible.
