First, the light resistance of colorants: it is related to its own chemical structure, and at the same time, it is related to its concentration and whether it is shared with watering down agent. The light resistance of inorganic pigment, whether it is thick color or light color, whether it is used alone or shared with titanium dioxide, its light resistance is higher. For organic pigments, their lightfastness can be summarized as follows: azo pigment < heterocyclic pigment; insoluble azo pigment < azo precipitated pigment; azo pigment < azo condensed pigment; small molecule pigment < large molecule pigment; small pigment particle size < large pigment particle size; shared with titanium dioxide < organic pigment used alone; low concentration < high concentration.
Second, the colorant and the colored material in the use of the environment in contact with the chemical hair should be. If a chemical reaction occurs, it may change the colorant's color properties, thus leading to color change. However, this factor is predictable, such as ultramarine pigment fading in acidic environment; chrome black and molybdenum chrome red pigment will generate lead sulfide in the presence of sulfide and make the color dull. Therefore, as long as the coloring agent is carefully chosen before color matching, this problem can be avoided.
Third, PVC resin aging. PVC resin in the light will also occur photochemical degradation reaction, so that the light reflectivity of the resin changes, which will also cause changes in the color of PVC plastic particles. But the degree of impact is much less than the previous two factors. From the colorant fastness performance. Acid resistance must be good, good heat resistance, good migration resistance, good light resistance.
Fourth, from the viewpoint of the physical properties of colorants index. Color stability is high (color difference, coloring power change is small); oil absorption is small (conducive to dispersion); water solubility is neutral or slightly acidic (good stability in the PVC coloring system); low dielectric content in water (good electrical performance); low moisture content (good processability, good electrical performance).
