If a foam rubber product factory receives a customer's complaint, it is found that the product deformation cannot be recovered shortly after the product is installed, that is, the product's permanent compression deformation is too poor. Then such a rubber product factory should start worrying about the quality of your rubber products. For the compression permanent deformation of molded foam rubber products, the following requirements should be met:
1. Test the proper gel content, the amount of filler affects the compression set. With the increase of the filling amount, the compression set decreases first, and then rises to an optimal value. Such as NBR rubber products O-ring, under the appropriate softening oil, filled with 50-70PHR carbon black compression permanent deformation is better; (recommended reading: how to control the shrinkage of rubber products)
2. Select a suitable filler. Generally white fillers, especially high fillers, will cause the compression set to become larger. Carbon black is the best rubber filler. However, if the foam is filled too little, the foaming effect and the surface of the product are not good; and foamed products generally require low hardness, and the amount of carbon black should not be too much. More white fillers need to be filled, so it is necessary to find the quality and the pressure change. Better white filler;
3. Foaming rate. It seems that the amount of foaming agent and compression set are also increasing with the amount, the compression change is small and then large, and the foaming rate is appropriately large, which is good for compression set. It is recommended to use OBSH, AC, or H in combination of about 3 servings, which will be more appropriate;
4. Select the appropriate sulfurization conditions. The effect of curing temperature and time on compression set is self-evident. But because it is a foamed product, it is necessary to find a suitable balance between the vulcanization speed and the foaming speed.