Paint common sense: the function of paint defoamer

Core tip: there are many antifoaming substances Defoamers can be divided into four categories: low alcohols, polar organic compounds, mineral oil and organosilicon Most of the defoamers used in practice are composed of several materials Mineral oil defoamer can be used in latex paint, which is composed of mineral oil, hydrophobic particles, a small amount of emulsifier, bactericide and other reinforcing components Hydrophobic particles generally use fumed silica, but also fatty acid metal salts and their derivatives A small amount of emulsifier makes defoamer easy to mix into coating evenly Mineral oil can replace surfactants on foam Paint knowledge | precautions for wall paint color selection Recommended introduction: when painting the wall, the owner sometimes has difficulty in choosing what color of the wall paint to paint In fact, there is no ugly color in the wall paint, only the disharmonious color matching The use of wall color contains the knowledge of health Too strong color will stimulate people's perception, make people have a sense of fidgety, affect people's mental health Grasp the basic principles of wall color and paint a colorful space 1、 Wall paint color selection notice 1 Light color is generally used for the top surface Light colors make people feel light, dark colors make people feel heavy Usually, the treatment of rooms is from top to bottom, from shallow to deep For example, the ceiling and walls of rooms are white and Paint Home News: can play a role in defoaming a lot of substances Defoamers can be divided into four categories: low alcohols, polar organic compounds, mineral oil and organosilicon Most of the defoamers used in practice are composed of several materials Mineral oil defoamer can be used in latex paint, which is composed of mineral oil, hydrophobic particles, a small amount of emulsifier, bactericide and other reinforcing components Hydrophobic particles generally use fumed silica, but also fatty acid metal salts and their derivatives A small amount of emulsifier makes defoamer easy to mix into coating evenly Mineral oil can replace foam surfactants, weaken the elasticity and cohesion of foam walls, and also serve as carriers for special paints to transport hydrophobic particles onto the foam wall to absorb or capture surfactants on the foam wall Mineral oil defoamers are not suitable for solvent based coatings because of the slow dispersion on the walls of such films Solvent based coatings need polysiloxane defoamer with lower surface tension A good defoamer is easy to cause film shrinkage because of its very low surface tension, while a weak defoamer has less shrinkage, but its effect is poor The molecular chain of polysiloxane is short, and its miscibility in paint is good, but it plays the role of stabilizing foam instead of defoaming The chain of polysiloxane is too long and miscible is too bad, though it is defoaming, it produces shrinkage defects It is necessary to modify polysiloxane with organic group to control its miscibility in the coating, which can not only defoamer, but also produce shrinkage cavity Defoamer has two functions: one is to ensure the smooth production, and the operation of defoamer is difficult The air in defoamer will not only hinder the dispersion of pigments or fillers, making the cup inefficient, but also need to be filled for many times The two is to ensure that the paint does not produce foam during construction, so that a good coating can be obtained In the production of water-based coating, defoamer can be added twice The first time is in the process of pigment dispersion, and the second time is in the process of paint mixing In the production of high gloss emulsion paint, strong defoamer is added during grinding, and defoamer with weaker defoamer capacity is added during mixing The solvent coating only needs to be added once in the mixing process 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,