Polypropylene is a pure hydrocarbon. The molecular chain contains tertiary carbon atoms. After being heated and exposed to light, the molecules at the tertiary carbon atoms are easy to crack, which deteriorates the quality of polypropylene. Therefore, the masterbatch made is required to be spun at high temperature. The medium is easy to diffuse, does not damage the fiber quality, does not make the fiber fade, has excellent light resistance, abrasion resistance, and solvent resistance, and can withstand strict spinning drafting.

     (1) The most basic requirement for the pigments used in the heat-resistant masterbatch is to withstand the temperature during the production of polypropylene fiber and maintain the stability of its performance. The temperature resistance is generally required to be above 270～280℃.

    (2) The pigment for dispersible masterbatch should have good dispersibility and be evenly dispersed in the masterbatch, and the dispersant used should not reduce the quality of polypropylene fiber. Otherwise, it is impossible to produce high-quality dope-colored fibers, and the operation is also unstable, and it is easy to break or produce abnormal fibers when the fibers are drawn.

    (3) There are many uses for the coloring of luster polypropylene stock solution. Among them, it is used for bed cover base cloth and knitted fabrics, which require bright colors. Because organic pigments are brighter and brighter, and easy to color, organic pigments should be used for the above purposes.

    (4) Light resistance. Some pigments have photosensitivity under the action of light, which can make colored fibers fade and brittle. The light resistance of pigments is basically related to their chemical structure, so pay attention to the light resistance of pigments when making masterbatches. When light-fast pigments need to be used, you can consider adding ultraviolet absorbers.

    (5) The pigment used in the stable masterbatch must have excellent stability to the colored polypropylene fiber. It means that the pigment will not react with the fiber when the colored fiber polymer is exposed to heat, light or high temperature for a long time, and new chemical groups are formed to make the polymer performance low. Therefore, the pigments should be as pure as possible in the masterbatch, free of iron, copper, lead and other salt impurities to ensure the excellent physical properties of the colored polypropylene fiber.

    (6) Water resistance, dry cleaning resistance, oil resistance, colored polypropylene fiber products will inevitably be washed with water or solvent dry-cleaned after use. They must come into contact with oils, especially when they are used on carpets, so the colorant used should be It has good washing resistance, dry cleaning resistance and oil resistance.