2021-10-19 Pageview:887
1, Broad-spectrum, kill many kinds of mold and yeast. Comply with EU requirements.
2, low toxicity, easy to operate, applicable ph range is wide, 5 ~ 10 can be used.
3, evenly dispersed, heat stable, non-combustible, easy to transport, stable under strong UV and acid rain conditions.
4, Passed astm e-1428-99 pink stain and astm g-21-96 mixed fungi test.
5, High safety, non-teratogenic, non-toxic.
6, has a strong ability to kill mold, with broad-spectrum bactericidal does not produce resistance, the effect of long duration.
The film forming mechanism of powder coatings and the causes of surface defects
During powder coating construction, the powder is sprayed on the substrate to form a powder layer of a certain thickness. The individual powder particles are melted and coalesced to form a continuous and uneven film by heating up, and then flowed and leveled to form a smoother and smoother film. The surface is finally cured by cross-linking reaction to form a hard coating film with a network structure. This process can be divided into micronized wax additives three stages: melt coalescence, leveling and solidification.
Film forming process of powder coating
The powder coating is prone to shrinkage in the process of baking and curing to form a film. When the surface tension of the coating film in the molten coalescence state is higher than the critical surface tension of the substrate and the substrate cannot be fully wetted, or when the substrate is not cleanly treated and there are oil stains and spots, it will cause shrinkage. In the process of heating and melting the film, the small particles produced by the poor wetting caused by the selective adsorption between the components, or the dust, oil droplets and other impurities that bring people during the processing, are formed in the coating film. The low surface tension points cause the coating film to flow from these low surface tension points to the surrounding high surface tension areas to produce shrinkage holes.
The key factors that affect the flow and leveling of the powder coating film are the powder particle size, the melting and coalescence speed of the resin and the melt viscosity, the surface tension gradient of the coating film, the degree of surface tension uniformity and the film thickness. The melt viscosity depends on the heating rate, solidification temperature and solidification speed. At a given temperature, the main conditions for controlling the speed of melting and coalescence are the melting point of the resin, the viscosity of the melt, and the size of the powder particles. In order to achieve the best flow effect, the melt coalescence process should be completed as quickly as possible to allow a longer time to complete the leveling phase.
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