In addition to superior product performance, silicone products have a unique advantage, that is, color change. A good product is first from the outside to the inside. Many people want to see the actual use of the product and also the appearance requirements. There are certain standards, most consumers are looking at the appearance of the product, so the appearance of the silicone product is naturally very important.


Solution coloring
The method is to dissolve the silicone rubber into a certain concentration solution by using a good solvent, and then adding the coloring agent and the silicone rubber compounding agent other than sulfur to the solution, stirring and mixing uniformly, drying and removing the solvent at a certain temperature, and finally refining. Add sulfur to the melter. The operation is complicated, the dispersion is uneven, there is color difference, the solvent is difficult to recycle, the environment is polluted, and it is less used.


Mixing method
This method is currently the most commonly used method for coloring silicone products. The coloring agent is directly added or mixed with the carrier and then added to the rubber compound, and uniformly mixed by the rubber mixing machine to color the silicone rubber. Specifically divided into the following methods.


Dry powder coloring
The powdered coloring agent is directly added to the silicone rubber along with the small material, and kneaded on an open mill. The utility model has the advantages of simple operation and low cost, but the dust is large during the mixing, pollutes the environment, and is not easy to disperse uniformly, and has a color difference. If the particles are too thick and too thick, the quality problems such as color point, stripe or chromatogram are mutually contaminated, and the use is less. .


Color paste coloring
The coloring agent is first mixed with a liquid compounding agent (such as a plasticizer), and is ground to a paste or a slurry by a three-roll mill, and then added to a silicone rubber in a certain ratio to be kneaded. This method can avoid dust flying, which is beneficial to the dispersion of coloring agent in rubber and uniform color. However, the content of the coloring agent in the color paste is low, the coloring is not high, the transportation amount is large, the loss is large, and the user is inconvenient to use.


Pellet coloring
There are two main methods for preparing colorant pellets. The first method is the same as other powder compounding granulation methods, in which the powdery coloring agent is first impregnated with a surfactant, and then waxed or melted and extruded with a resin to be granulated; the second method is to use a coloring agent. After the surfactant is infiltrated, the colorant particles are refined by mechanical force to form a dispersion of a certain concentration, and then mixed with the latex, and dried and then granulated. The granular coloring agent is convenient to use, has good dispersibility, no dust flying, does not pollute the environment, has bright color, uniform hair color and no color difference, and is a promising coloring method. However, the preparation process of the granular coloring agent is complicated and the cost is high, which limits its wide application.