When toning, according to the requirements of the object to be colored, it is necessary to establish quality indicators such as the physical and chemical properties of the pigment product. Specific items are: tinting strength, dispersibility, weather resistance, heat resistance, chemical stability, migration resistance, environmental performance, hiding power, and transparency.
Tinting strength: The size of tinting strength determines the amount of colorant. The greater the tinting strength, the less pigment dosage and the lower the cost. The tinting strength is related to the characteristics of the pigment itself, as well as its particle size.
Dispersibility: The dispersion of the pigment has a great influence on the coloring, and poor dispersion can cause abnormal color tone. Pigments must be uniformly dispersed in the resin in the form of fine particles to have a good coloring effect.
Weather resistance: Weather resistance refers to the color stability of the pigment under natural conditions, and also refers to the light fastness. It is divided into grades 1 to 8, and grade 8 is the most stable.
Heat-resistant stability: Heat-resistant stability is an important indicator of plastic colorants. The heat resistance of inorganic pigments is relatively good and can basically meet the requirements of plastic processing; the heat resistance of organic pigments is relatively poor.
Chemical stability: Due to the different use environments of plastics, it is necessary to fully consider the chemical resistance properties of colorants (acid resistance, alkali resistance, oil resistance, solvent resistance).
Migration resistance: The migration resistance of pigments refers to the long-term contact of colored plastic products with other solid, liquid, gas and other state substances or working in a specific environment, which may have physical and chemical effects with the above substances, which is manifested as pigments from Internal migration of plastic to the surface of the article, or to adjacent plastic or solvent.
Environmental performance: With the increasingly strict environmental protection regulations at home and abroad, many products have strict requirements on the toxicity of plastic colorants, and the toxicity of colorants has attracted more and more attention.
Hiding power: The hiding power of a pigment refers to the size of the transmission ability of the pigment to cover light, that is to say, when the refraction power of the toner is strong, the ability to prevent the light from passing through the colored object.
Transparency: Toners with strong hiding power are definitely poor in transparency, inorganic pigments are generally opaque, and dyes are generally transparent.
References:
[1] Zhong Shuheng. Color Composition. Beijing: China Art Publishing House, 1994.
[2] Song Zhuoyi et al. Plastic raw materials and additives. Beijing: Science and Technology Literature Publishing House, 2006.
[3] Wu Lifeng et al. Masterbatch User Manual. Beijing: Chemical Industry Press, 2011.
[4] Yu Wenjie et al. Plastic Additives and Formulation Design Technology. 3rd Edition. Beijing: Chemical Industry Press, 2010.
[5] Wu Lifeng. Plastic Coloring Formulation Design. 2nd Edition. Beijing: Chemical Industry Press, 2009
Post time: Apr-23-2022