3 factors affecting the luster of matting powder
1, The roughness of the matting powder coating surface
2, The film formation process of matting powder coating film
3, Matting powder pigment, particle size and distribution of fine material
With the further addition of surfactants, typical micelles will form, and the surface tension will drop to a minimum or remain stable. The concentration of the surfactant at this lowest point is called the critical micelle concentration, abbreviated as CMC (critical micelle concentration) value. When the surfactant reaches the minimum concentration, every several molecules will form a spherical, rod-shaped or layered aggregate, their lipophilic groups are close to each other, and the hydrophilic groups extend outward to the water phase. At this time, fatty amide wax, the aggregates are called micelles. For example, typical base surfactant coating additives
The characteristic CMC curve of Tex ap on*K 12 (needle, sodium lauryl sulfate) is shown in Figure 1-3. The test method is based on the Lecomte duNo uy ring method (25°C).
In most cases, the amount of emulsifier added during emulsion polymerization is greater than their CMC value. This is because micelles are produced by surfactants, and only micelles can solubilize monomer droplets dissolved in the water phase.
Generally, anionic surfactants are responsible for the formation of colloidal particles. In the absence of application requirements, the choice of anionic surfactant will depend on the required particle size. Surfactants with high CMC, such as succinate, are easier to form larger particles. But succinate can also get a narrower particle size distribution, which may be due to the packaging effect and the higher number of micelle aggregates. The use of succinate in the emulsion polymerization process is summarized and introduced.
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