Why are the colors of circular manhole cover so rich?

Why are the colors of circular manhole cover so rich?

Most of the manhole covers on the sidewalk are resin manhole covers. Although the load-bearing capacity of this kind of manhole covers is not as high as that of cast iron manhole covers, they are still very safe to use on the sidewalk. The resin manhole covers are mostly made of resin materials. Due to the particularity of the raw materials, the color will be particularly distinguished from other types of manhole covers.

One reason for the rich colors of the manhole covers is that they can be colored. The second is to use the high-temperature oxidation method to put it in a specific molten salt, so that through a chemical reaction, the manhole cover can show different colors. The color of the manhole cover can be changed by chemical methods. Like resin manhole covers, there are many types of colors, and this kind of manhole cover is more artistic and can be designed with many different patterns 

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