Why are some plastic water cups transparent and colorless? Are some colored and translucent?

So how is the translucent effect of plastic water cups achieved?

There are two ways to achieve translucency in plastic water cups. One is to add materials such as additives (masterbatch) of various colors including white, and control the added proportion to achieve the translucent effect of the finished product; the other way is to By spraying, spraying transparent oil or paint can also achieve a translucent effect on the surface of the water cup. Water cups produced through additives can remain translucent for a long time, but once the coating on a translucent water cup produced through spraying peels off, the water cup will gradually lose its translucent effect.

Complete opacity can also be achieved by using additives and spraying, increasing the proportion of additives or changing the color and thickness of the paint.

Regarding frosted translucency and frosted opacity, in addition to being somewhat similar to the previous ones, such effects can be achieved through special processing of the mold, such as through the specific gravity of additives or spraying. Usually, the most commonly used method is mold tanning. There are many ways to pattern, and many mold manufacturing factories use the most common engraving process. Due to the accuracy of the engraving process and the hardness of the material, the frosting effect of the plastic water cup produced by the sun-textured mold is worse than that produced by spraying. The frosted effect produced by spraying is more natural, delicate and uniform.