What is the hardness of silicone keys?

The hardness of the silicone key is determined by the raw material of silicone. The common silicone hardness is 30 ，50， 70 . The higher the hardness of the silicone key, the better the feel of the keypad will be. However, if the hardness is too high, it will also affect the service life of the keypad. The lower the hardness, the softer the keypad corresponding to the silicone key, the worse the feel, and the friction between the key and the plastic hole will increase, which is easy to cause key sticking. Therefore, our silicone keys generally require silicone hardness of 50 ° or 60 °.

Now some friends may say, "I want to customize the hardness of silicone keys, which is not 50 °, but 55 °?

When the hardness of silicone keys customized by customers is not in the value of common silicone hardness, we should adjust the hardness according to customers' requirements. As mentioned above, we need to prepare 55 ° silicone rubber. First, let's talk about the down-regulation formula:

(target hardness - low hardness) ÷ (high hardness - low hardness) x required weight = weight of high hardness compound

Required weight - weight of high hardness compound = weight of low hardness compound

For example, we need to prepare 55 shoreA 10kg silicone rubber and adjust it with 50 ° and 70 ° silicone rubber. According to the formula, we can calculate that the weight distribution of 2.5kg 70 ° silicone rubber plus 7.5kg 50 ° silicone rubber can prepare 55 ° silicone rubber. The same is true for other degrees of silicone rubber.

Although 30 ° silicone rubber and 70 ° silicone rubber can also be 55 ° silicone rubber, it is not recommended to use 30 ° and 70 ° silicone rubber to mix, because these two kinds of rubber are mixed together, which is not only extremely sticky when mixing, but also very sticky when forming by hydraulic pressure, which will cause certain difficulty in demoulding, especially the silicone rubber key with complex structure in silicone rubber products.