Why does the silicone tube produce belt marks?

Why does the silicone hose produce belt marks?

First of all, the vast majority of this kind of belt printing comes from the silicone hose production process. That is because some silicone tubing manufacturers lack a step in the process. The traditional process of extruding the silicone hose usually requires a high-temperature oven to process the silicone hose. Cross-linking factor vulcanization, the temperature in this step is much higher than the temperature in the drying tunnel, so that the silicone hose can be preliminarily shaped, that is, the surface of the silicone hose has basically been crusted and matured, but the silicone inside the wall thickness is not completely vulcanized. Therefore, it is necessary to re-vulcanize the drying tunnel, so that adding an oven between the drying tunnel and the extruder will not cause the problem of belt marks, because the surface of the silicone hose has been cured and formed, so even if it is placed on the conveyor belt, it does not matter. There will be a belt print problem!

As for the problem of belt printing, the lack of the oven process will lead to this problem on the surface of the silicone hose, because the silicone hose immediately enters the conveyor belt of the drying tunnel for vulcanization after being extruded from the die mouth. Note that at this time the surface of the silicone tube is not vulcanized, but it is still in the state after the silica gel is densely trained. It is only pushed out of the mold mouth by the threaded rod (at this time, the soft silicone will leave traces if it is stimulated by the outside world) and the conveyor belt of the drying tunnel is not It will be replaced every day. As the conveyor belt continues to age or become incomplete and absorb dust, at this time, after the silicone tube sticks to the conveyor belt, an uneven surface will appear immediately, which is the source of the belt printing. If the belt print has been formed, the post-drying tunnel cannot change the surface of the silicone tube, so this will happen after molding.

Why not add an oven process to the extrusion equipment and drying tunnel to solve the belt printing? It should be in some relatively niche fields or because of cost considerations, adding a high-temperature oven process to the medium and continuous high-temperature irradiation is a waste of electricity, so in the eyes of some manufacturers, reducing such an oven can save money. Lots of electricity bills.

Another important reason is that the silicone hose needs to wrap some other materials such as LED light strips, ropes or other items. As mentioned earlier, the problem of this oven is relatively high. All materials that are not resistant to high temperature are prone to problems when using this oven. It is also the problem that many manufacturers have to choose this process because they know how to solve the belt marks. In this case, belt marks on the surface of the silicone hose are inevitable! Among them, the extrusion process in the silicone hose bears the brunt. This is generally more in the field of finished LED light strips, which is often referred to as integrated light strips. Because silicone needs to wrap the LED light strips and vulcanize together, it cannot enter this high temperature. The oven is preliminarily vulcanized, and it needs to directly enter the front drying tunnel to form, and then directly print the belt firmly on the surface of the silicone sleeve! Because the LED light strip cannot withstand the high temperature after entering the high temperature oven, necrosis will occur.