That, as in all rubbers, since sponge rubbers are manufactured in different types of rubber, depending on the use. That is, for example, there are closed-cell spongy rubbers in nitrile, in natural rubber, in neoprene, in SBR.
It is manufactured in a high variety of rubbers so that, for example, nitrile holds fuel well. Well, that has to be made of nitrile closed or semi-closed cell rubber, because if it is not made of nitrile, it will not resist hydrocarbons.
Then it’s going to come undone. If the rubber you make has to withstand high temperatures, then you have to use neoprene, which will be suitable for high temperatures. If the rubber you are going to use has to have a lot of resistance to tearing, then you cannot use EPDM, you have to use natural rubber in closed cells. In other words, in each situation there is a rubber that is better or worse. So, well, depending on what the client explains to you, where he is going to go, how he is going to go, well, you have to guide him to what type of rubber and what density he is most interested in for what he is explaining to you.
For example, if a guy asks you to make a vacuum system for some cranes that handle wooden planks, you have to give him a rubber that is soft, that adapts well to the differences. That has surface differences and that has resistance to attraction.
I mean, well, for example, in this case the semi-closed cells, well, they work very well.