Common knowledge of coatings: analysis of the causes of color blooming of coatings and floating color blooming of solvent based coatings

Core tip: the color blooming of paint refers to the uneven distribution of a variety of pigments in the paint film after coating, usually in the form of stripes or honeycombs, which can be understood as the separation of pigments in the vertical direction Floating color refers to the horizontal layer separation of pigments in the wet film after coating, that is to say, one or several kinds of pigments in the film concentrate on the surface with high concentration and distribute uniformly, but there are obvious differences with the color of the original formula Many components in the paint system (such as pigment, filler, base material, solvent, etc.) may be the cause of floating color and blooming 1 Due to the sedimentation and flocculation of pigments 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: paint color hair spray refers to the uneven distribution of a variety of pigments in the coating film after coating, usually in the form of striped stripes or honeycomb, which can be understood as the separation of pigments in the vertical direction Floating color refers to the horizontal layer separation of pigments in the wet film after coating, that is to say, one or several kinds of pigments in the film concentrate on the surface with high concentration and distribute uniformly, but there are obvious differences with the color of the original formula Many components in the paint system (such as pigment, filler, base material, solvent, etc.) may be the cause of floating color and blooming 1 In the paint dispersion system, the pigment ions have uneven settlement due to the different apparent density reflected in the paint The pigment particles with small density float up relative to the sinking of the pigment particles with large density, resulting in the floating color on the surface of the film 2 Because of the floating color caused by solvent, too much or improper selection of solvent, too strong solubility will make the viscosity of the coating sharply drop, low viscosity of the coating will cause the settling speed of the pigment particles to accelerate, and the settling difference of the pigment particles with different particle sizes will occur, which will cause the color of the coating to blossom In the mixed solvent, the evaporation speed of the true solvent is too fast, which will not only produce the surface tension difference, but also destroy the solvent balance A part of the resin will be separated with the adsorbed pigment due to the reduction of the true solvent, which will cause the flower, and there will be agglomerated particles, which will affect the surface flatness of the film Too slow volatilization of solvent will lead to too slow rise of coating viscosity, too long flowing time of coating film, easy occurrence of Bernard vortex, flower, floating color, sagging and other problems 3 For the floating color and blooming caused by the base material, the wetting ability of the base material for various pigments mixed with pigments in the paint is different, and the adsorption ability of various pigments for the base material is also different The pigments not well wetted may cause floating color and blooming due to the agglomeration phenomenon When the base material is composed of different resin synthesis, the different solubility is also one of the reasons for floating color There are two situations: one is that the mutual solubility of several resins used is not good; the other is that the solvent used is not good If several resins are not well miscible, another situation is that the solvent selected has poor solubility If several resins are miscible and have different affinity to pigments, even if turbidity is eliminated under the action of solvent, the phenomenon of floating color and blooming will occur after solvent volatilization The phenomenon of floating color also starts in the process of solvent volatilization, because the volatilization of solvent and diluent destroys the equilibrium relationship of resin dissolution, and the resin with poor compatibility will bring out the adsorbed pigment when it is separated out, causing floating color or blooming 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,