Commonly Used Plastic Coloring Methods

When light acts on plastic products, part of the light is reflected from the surface of the product to produce luster, and the other part of the light is refracted and transmitted into the interior of the plastic. When encountering pigment particles, reflection, refraction and transmission occur again, and the color displayed is the pigment particles. The reflected color.

Commonly used plastic coloring methods are: dry coloring, paste colorant (color paste) coloring, color masterbatch coloring.
1. Dry coloring
The method of mixing and coloring directly with toner (pigments or dyes) adding appropriate amount of powder additives and plastic raw materials is called dry coloring.
The advantages of dry coloring are good dispersibility and low cost. It can be arbitrarily specified according to needs, and the preparation is very convenient. It saves the consumption of manpower and material resources in the processing of colorants such as color masterbatches and color pastes, so the cost is low, and buyers and sellers do not need to use it. It is limited by the amount; the disadvantage is that the pigment will fly dust and cause pollution during transportation, storage, weighing and mixing, which will affect the working environment and the health of operators.

2. Paste colorant (color paste) coloring
In the paste coloring method, the colorant is usually mixed with a liquid coloring auxiliary (plasticizer or resin) and ground into a paste, and then it is evenly mixed with plastic, such as color paste for enamel, paint, etc.
The advantage of pasty colorant (color paste) coloring is that the dispersion effect is good, and dust pollution will not be formed; the disadvantage is that the amount of colorant is not easy to calculate and the cost is high.
3. Masterbatch coloring
When preparing color masterbatches, the qualified color pigments are usually prepared first, and then the pigments are mixed into the color masterbatch carrier according to the formula ratio. The molecules are fully combined, and then made into particles similar in size to resin particles, which are then used by molding equipment to make plastic products. When used, only a small proportion (1%~4%) needs to be added to the colored resin to achieve the purpose of coloring.
Compared with dry coloring, masterbatch coloring has the following obvious advantages: improving the environmental pollution caused by flying toner, easy color changing during use, no special cleaning of the extruder hopper, and stable formula It has strong performance and can ensure that the color of the two batches of color masterbatches of the same brand remains relatively stable. The disadvantage of masterbatch coloring is that the coloring cost is high and the preparation quantity is not flexible. In addition, pearlescent toners, fluorescent powders, luminous powders and other toners are made into color masterbatches and then used to color plastics. Compared with directly mixing plastics for coloring, the effect (such as gloss, etc.) is weakened by about 10%, and injection molding products are also prone to flow lines. Stripes and seams.

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