Solution to Too Hard Liquid Silicone rubber

After solidification, liquid silicone rubber can be soft or hard, and the hardness of silicone rubber varies with the proportion of curing agent added. The hardness of silicone rubber determines its use. As users who use silicone rubber for the first time are not sure what kind of hardness they need, the hardness of the purchased silicone rubber may not be suitable. Below are two solutions to solve the problem of too hard silicone rubber.

Method 1: We can use silicone oil to reduce the hardness of silicone rubber. Generally, adding 1% silicone oil will reduce the hardness of silicone rubber by about 0.9 to 1.1 degrees; Adding 10% silicone oil will reduce the hardness of the silicone rubber by about 5 degrees. However, in practical operation, if the silicone oil ratio is too high, the molecular weight of the silicone rubber will be damaged, and the tear resistance and tensile strength will correspondingly deteriorate, affecting the service life of the silicone rubber mold. In addition, if the silicone oil ratio is too large, the silicone rubber mold will easily deform.

Therefore, we recommend that the ratio of silicone rubber to silicone oil generally not exceed 5%, and try to add silicone oil with a higher viscosity. If you add more than 5% silicone oil, please try a small amount first to determine whether the mold made can be used.

Method 2: Mix high hardness silicone rubber and low hardness silicone rubber. The prerequisite for using this method is to purchase two types of silicone rubber with different hardness, such as 20 hardness silicone rubber and 10 hardness silicone rubber. After mixing, the hardness of the silicone rubber is around 15 Shore A. When using this mixing method, it should be noted that condensed silicone rubber cannot be mixed with addition molded silicone rubber, otherwise it may cause non curing.