1, EL-9070 will react with isocyanate and and phenolic amine curing agent, please test the curing agent species before use to avoid product gelling.
2, This product contains amine group, the color may become darker after a long time, but it does not affect the performance.
3, Before painting, the grease and liquid on the substrate must be wiped clean to avoid affecting the adhesion effect.
The problem of film sagging and poor corner coverage is caused by the low melt viscosity of the powder coating and the slow reaction speed of the resin and curing agent. The former can be covered by adding anti-sagging agent and corner coverage. Strength improvers can improve the melt viscosity of powder coatings, reduce the melt horizontal fluidity and inclined fluidity of powder coatings to solve the problem; the latter can be solved by adjusting the reactivity of powder coatings. The sagging phenomenon of the coating film is easy to occur in the electrostatic powder coating, when the coating film thickness is too thick; the problem of poor coverage of the corners of the coating film, in the fluidized bed dip coating, it is easy to occur when coating objects with edges and corners. ; In electrostatic powder coating, the edge of the coated object is sharp, or the melt viscosity of the powder coating is too low, or the thickness of the coating film is too thick.
The main function of the anti-sagging agent and the corner coverage improver is to increase the melt viscosity of the powder coating, or to cause the powder coating to produce thixotropic effect when it is melted and leveled, so that the thickness of the coating film on all parts of the coated object is uniform, and the coating film flow is avoided Problems such as uneven coverage of hanging or corners. Because the effect of anti-sagging agent and corner coverage improver is limited, first of all, in the formulation design, according to the requirements of the thickness of the coating film, select the resin with the appropriate melt viscosity, and the resin and curing agent with reasonable reactivity. For the system, it is necessary to select appropriate pigments and fillers and the amount in the formula. On this basis, those that cannot meet the requirements can be further solved by adding anti-sagging agents and corner coverage improvers.
The commonly used anti-sagging agents and corner coverage improvers in powder coatings include polyvinyl butyral and ultrafine fumed silica. The main function of polyvinyl butyral is to increase the melt viscosity of powder coatings during melt leveling; the function of ultra-fine fumed silica is thixotropy. The dosage of polyvinyl butyral in the formula is 1% to 5% of the total formula; the dosage of fumed silica in the formula is 0.5% to 2% of the total formula. The polyvinyl butyral produced by Hunan Xiangwei Co., Ltd. The product specifications of vinyl butyral are shown in Table 25-12. Among the models with a melting temperature of about 160°C, SD-3 and SD-4 have better effects.
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