1. How is the bubble in the coating film generated? The bubble is a gas mixed into the coating and remains on the surface of the coating film to form a small bubble. A. In the preparation of paint liquid, adding curing agent and blending agent, during the stirring process, the air entrainment caused by mechanical movement during the filtration process of the paint liquid. B. During construction, a large amount of air will be entrained in the paint brush. When the brush is applied, it will remain in the wet film to form a bubble. The substrate is not flat, the substrate is loose, the void is filled with the paint liquid, and the air will form bubbles. C. The gas released by the chemical reaction forms a bubble, such as moisture, the solvent does not contain moisture, the entrained water in the compressed air during painting, and the poor diluent contains a small amount of acid, alcohol, amine, etc., and the curing agent The reaction releases carbon dioxide gas to form a bubble. Second, the bubble burst process: A, in the paint liquid, the rising speed of the bubble: V = kx (r2 / y) (V: bubble rising speed k: constant r: bubble radius y: viscosity of paint liquid) It can be seen that the larger the bubble, the faster the speed rises to the paint surface, the larger the paint liquid stick shop, and the slower the bubble rises. B. The liquid discharge effect of vapor light: When the bubble rises to the surface of the paint liquid, the liquid flows to the lower side of the bubble, and the bubble wall gradually becomes thinner. When the thickness of the bubble wall is less than 10 nm, the bubble bursts. C. The surface tension of the antifoaming agent is particularly low, which makes the bubble wall more easily thinned, and causes the bubble to be more easily broken. D. Using a solvent with a low surface tension, it is not easy to generate bubbles. E. During construction, the paint liquid is thin and the viscosity is low, and the formed bubble is easily broken. H4 Led Headlight,H4 Headlight,H4 Led Headlight For Car,H4 Led Bulb For Car CHANGZHOU CLD AUTO ELECTRICAL CO.,LTD , https://www.cld-led.com
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