The poor dark mark (ripple) of silicone rubber products belongs to one kind of poor appearance of silica gel products, which is characterized by two colors or disorderly ripples on the surface of silica gel products after molding, and the ripple distribution is disorderly.

The solution is as follows:

1. The silicone rubber products are mixed unevenly when preparing materials, which means that the mixing time is too short after the addition of color masterbatch, resulting in the color masterbatch not being completely dispersed evenly, resulting in the poor dark mark (ripple) of silica gel products during the molding of silicone rubber products. This problem can be solved by re refining raw materials.

2. If the vulcanization temperature is too high, any kind of silicone rubber masterbatch has its temperature resistance. When the vulcanization temperature exceeds the upper limit of the temperature resistance of the color masterbatch, it will cause the color masterbatch to change color at high temperatures. If the temperature resistance values of several color masterbatch used for silica gel products are different, it may cause a color masterbatch to change color, but a color masterbatch does not change color, and naturally there will be dark marks (ripples) on silicone rubber products. It is necessary to adjust the mold temperature to solve the problem. The answer is how much the temperature decreases until there is no dark mark (ripple).

3. When the mold temperature was continuously reduced, the problem of dark marks (ripples) on silicone products was solved, but incomplete vulcanization (unripe) of silicone products occurred. It is basically that the temperature resistance of silica gel color masterbatch itself is too poor, which usually appears on some color masterbatch with bright colors such as red, green and yellow. The temperature resistance of such color masterbatch will be relatively poor. If it is used to match with other color masterbatch, it is easy to have bad dark marks (ripples) of silica gel products. At this time, it is necessary to consider looking for color masterbatch with similar color to re color to solve such defects.

4. In normal production, it may be that a certain type of color paste has never had dark marks (ripples) on silicone products when it was used before, but when it was used for color mixing, dark marks (ripples) appeared. It is likely that this type of color paste is incompatible with a certain color paste, resulting in poor dark marks (ripples) after silicone products are formed. The solution is simple, just replace the color paste.

5. The unreasonable discharge of the rubber material during the molding of silicone products is the most likely factor to cause the bad dark mark (ripple) of silicone products. Because the silicone material is cut too thick and too narrow, the rubber material is heated unevenly, resulting in the bad dark mark (ripple) of silicone products. On the contrary, the improvement method is to change the cutting specification of the rubber material into thin and wide, so that it can completely cover the key type.

6. The silicone rubber products have been stored for a long time after being prepared, which leads to poor fluidity of the rubber materials, thus resulting in poor dark marks (ripples) of silicone rubber products. In addition, if too much curing agent is added during material preparation, such defects will also be caused.

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https://www.siliconerubbers.net/product-precipitated-grade-self-lubricating-rubber.html