Coating classification: defoaming of elastic coating

Core tip: there will be bubbles in the production and use of paint, which will bring inconvenience and influence to the production and construction The air in the bubbles comes from the mixing of air in the production process, the interception of air in the application of paint, and the gas produced by chemical reaction (such as paint containing isocyanate) Bubbles in the film produce surface defects such as cavities, pinholes, prickles, craters, etc Bubbles are completely trapped in the film to form prickly heat, and the opening of bubbles is broken Some bubbles are trapped in the film to form cavities, such as pinholes, craters or channels The formation of bubbles is related to the surface tension (γ) of the liquid system Application scope and advantages of roller ceramic coating Recommended introduction: the surface of ceramic rubber plate used for roller ceramic coating is cast into durable rubber plate by hundreds of independent small ceramic pieces Each ceramic piece has raised characteristics Under general conveyor belt pressure, thousands of unique cast bumps can produce positive traction, prevent slipping and extend the service life of conveyor belt roller At the same time, the bottom layer adopts high-quality rubber, which has strong elasticity and can play a good impact resistance role The scope of application of roller ceramic coating is one three six 83857180 (the same as V) 1 Roller coating in extremely harsh working environment 2 The belt joint is not suitable for fixing with iron buckle; 3 It is suitable for leather Paint Home News: there will be bubbles in the production and use of paint, which will bring inconvenience and influence to production and construction The air in the bubbles comes from the mixing of air in the production process, the interception of air in the application of paint, and the gas generated by chemical reaction (such as paint containing isocyanate) Bubbles in the film produce surface defects such as cavities, pinholes, prickles, craters, etc Bubbles are completely trapped in the film to form prickly heat, and the opening of bubbles is broken Some bubbles are trapped in the film to form cavities, such as pinholes, craters or channels The generation of bubbles is related to the surface tension (γ) of the liquid system When a certain mechanical work (such as stirring work) is input into a certain system, bubbles will be generated The total surface area of bubbles is related to the input mechanical work and the surface tension of the system as follows: w = γ In formula A: W - mechanical work; γ - surface tension of the system; a - total surface area of bubbles Therefore, in latex paint In production, especially in the production of elastic latex paint, due to the use of a large amount of emulsion, wetting dispersant and so on, the surface tension of the coating system is reduced, and bubbles are easily generated After the bubbles are formed, the stability of the foam is closely related to the viscosity of the medium, the foam material in the coating system and the penetration and diffusion ability of the defoamer, and the stability of the foam is related to the following factors: 1) The apparent viscosity of the liquid around the bubble membrane plate affects the penetration, diffusion and drainage of the defoamer; 2) the electrostatic repulsion force (Coulomb force F = q1q2 / r2) of the active molecular layer on the surface of the bubble membrane plate hinders the bubble rupture; 3) the Gibbs elasticity (E = Dr / DA) of the bubble membrane plate hinders the bubble rupture; 4) Ma Lan's brother's effect prevented the bubble from deforming, resumed the thickness and shape of the bubble film, prevented the bubble from breaking The first one was the effect of high viscosity factors on defoaming The high viscosity hinders the defoaming, and the low viscosity is good for defoaming After the three bubble is subjected to external interference, the bubble film thickness is reduced, and the foam is stabilized and the rupture is prevented From the analysis of the factors influencing the stability of the foam, it is necessary to weaken the stabilizing factors of the system and obtain the low viscosity slurry to create the conditions for defoaming Therefore, deaeration and defoaming of elastic coatings are closely related to emulsion and wetting agents They contain bubbles and foam stabilizer, while pigment, filler and dispersant affect the viscosity of slurry preparation, thus affecting the accumulation and rise of bubbles, and ultimately affecting defoaming The strength of defoamer determines the completeness of foam in the coating Home of coatings is specialized in coatings, diatom mud, paint coating, coating technology, fire retardant coating news and coating, diatom mud, paint coating, coating technology, fire retardant coating decoration knowledge and decoration renderings,