Colouring Classification of Silicone rubebr Products
In addition to superior product performance, silicone rubber products also have a unique advantage, that is, color change. A good product is first from outside to inside. Many people want to see the actual effect of the product, but also have certain standards for the appearance. Most consumers are interested in the appearance of the product, so for silicon. The appearance of rubber products is naturally very important.


Solution Coloring
The method is to dissolve silicone rubber into a certain concentration solution with its good solvent, then add colorant and silicone rubber compound except sulfur yellow into the solution, stir and mix evenly, dry the solvent at a certain temperature, and finally add sulfur yellow to the rubber mixer. The operation is complex, the dispersion is not uniform, the color difference is colored, the solvent is difficult to recover, the environment is polluted and less used.


Mixing coloring
This method is currently the most commonly used method for coloring silicone rubber products. It is to add the colorant directly or mix with the carrier first and then with the rubber compound. The silicone rubber is colored by mixing evenly through the rubber mixer. It can be divided into the following methods.


Dry pink colouring
The powder colorant is directly added to the silicone rubber with the small material and mixed in the smelter. The advantages are simple operation and low cost, but the mixing dust is large, polluting the environment, and is not easy to disperse uniformly, with color difference. If the particles are too hard and coarse, it will cause quality problems such as color spots, stripes or chromatographic cross-contamination, which are seldom used.


Colouring paste
Firstly, the colorant is mixed with liquid compounding agent (such as plasticizer), then the paste or paste is made by grinding with a three-roll mill, and then the paste is mixed into silicone rubber in a certain proportion. This method can avoid dust flying, and is conducive to the dispersal of colorants in rubber, with uniform color. But the colorant content in the paste is low, the coloring is not high, the transportation is large, the loss is large, and the user is inconvenient to use.


Granular colouring
There are two main preparation methods of colorant granules. The first method is to infiltrate the powder colorant with surfactant, then melt it with wax or melt with resin and extrude it into granules. The second method is to infiltrate the colorant with surfactant and then refine the particles of the colorant by mechanical force to form a certain concentration of dispersions. Then it is mixed with latex and co-precipitated, dried and rolled to granulate. Granular colorants are easy to use, good dispersibility, no dust flying, no pollution to the environment, bright color, uniform hair color, no color difference. It is a promising coloring method. However, the preparation process of granular colorant is complex and high cost, which limits its wide application.