2021-12-19 Pageview:515
Lubrizol 2063 is a viscous liquid and is recommended to be added during the grinding stage or at high or low speed during the blending stage. For use in aqueous systems, it can be neutralized with ammonia to pH 7 or added directly to systems that have already been added with ammonia. This product has acid function, it has catalytic effect, which makes amine based lacquer cross-linked during baking, therefore, the amount of catalyst can be reduced or the baking temperature can be lowered.
The addition rate is usually 1-2% of the total formulation (W/W), in some cases 3% of the total. The addition amount is the amount that can be added by testing to find the right adhesion.
The variety of additives used in thermoplastic powder coatings is less than that of thermosetting powder coatings. Wrinkle agents, orange line agents, sand texture agents, fringing agents, pattern agents and other additives used in thermosetting powder coatings are not used in thermoplastic powder coatings. superior. The main types of additives are boosters, anti-aging agents, UV absorbers and so on.
The resin used in thermoplastic powder coatings has a high degree of polymerization, a large molecular weight, and a strong toughness. It cannot be pulverized at room temperature with a simple mechanical pulverization method like a thermo-peripheral resin. Generally, freezing pulverization or shearing is required. The powder-cutting method is used for pulverization, and the pulverization effect is relatively low, and it is also difficult to pulverize into a very fine powder. In addition, the softening point of the thermal resin is relatively high. Under the baking temperature of the powder coating, the melt viscosity is very high, the leveling of the coating film is not good, the coating film thickness is relatively thick, and it is difficult to achieve a thin coating film; There is no polar group in the structure, and the adhesion to the substrate is not good. In order to improve the adhesion, it is necessary to apply a primer: the wettability of the material and the filler is also poor, and the dispersion of the pigment and the filler is not good. The addition amount is also relatively small. Due to the limitations of thermal resins, the variety of thermoplastic powder coatings is obviously less than that of thermosetting powder coatings, and the application range is relatively narrow. At present, the most widely used thermoplastic powder coatings in my country are polyethylene powder coatings. In addition, there are Polyvinyl chloride, ylamine (nylon), polystyrene sulfide and polyvinyl fluoride powder coatings, other types of thermoplastic powder coatings are rarely used, and the characteristics of thermal powder coatings and thermosetting powder coatings are compared.
Thermoplastic powder coatings mainly adopt fluidized bed coating method to coat metal fences and pipes to meet the requirements of anti-corrosion and decoration. Fluidized bed coating process requirements. The powder coating has good (dry powder) fluidity and the formed coating has excellent Good adhesion and long-term weather resistance (used for more than 15 years). The fluidity of the powder coating (dry powder) depends on the particle shape of the powder coating. It is better to be close to the spherical shape. The gauge density is above 0.35g/cm and the angle of repose should be less than 35°. In addition, the particle size distribution of the powder coating also has an impact. For polyethylene powder coatings, the powder particle size distribution of 50~80 mesh accounts for 70%~80%, and the powder particle size distribution of 80~100 days accounts for 15%~20%.
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