How to choose water-based paint dispersant

Coating dispersants are additives that improve and improve the dispersion performance of solid or liquid materials. When solid coatings are ground, dispersants are added to help crush particles and prevent crushed particles from condensing while maintaining dispersion stability. Oily liquid insoluble in water can be dispersed into very small droplets under high shearing force, after stopping stirring, quickly layered under the effect of interface

, and stirred after adding dispersant, it can form a stable emulsion . Its main function is to reduce the interface tension between liquid-liquid and solid-liquid.
in the components of water-based coatings, there are film-forming substances, solvents (water), pigments, additives. One of the additives is the smallest proportion of the paint, but it is also an important part, can not be ignored. The vast majority of pigments used in water-based coatings are mixed in the form of aggregates and condensates. If these particles cannot be dispersed into smaller particles or primary particles, and form a stable dispersion, there will be back to coarseness, flocculation, precipitation, floating hair flowers, coloring force reduction and other defects. Water-based coating additives - dispersants, the main role is to reduce the time and energy required to complete the dispersion process, stabilize the dispersed pigment dispersion, modified pigment particle surface properties, adjust the motion of pigment particles. The dispersants used in water-based coatings must be water-soluble and they are selectively adsorbed to the powder-water interface. Water-based industrial coatings and ordinary architectural coatings have a great difference, viscosity is generally low, with the application of -4 cups to measure viscosity, generally 60-120s, so water-based industrial coatings on the dispersant requirements, in addition to having a good viscosity, but also need to have a good anti-sinking performance.
the quality of coating slurry dispersion is not only related to the formulation of material formulation and the selection of raw materials, but also related to dispersants. Therefore, in the process of coating production, pigment dispersion is a very important production link, it is directly related to the storage of coatings, construction, appearance and the performance of paint film, so the reasonable selection of dispersants is a very important production link. The types of dispersants are anion, cation, non-ion, sex and polymer.
most dispersants are used to disperse pigments through the process of wetting, grinding and dispersing, evening and wrapping stability. In water-based coatings, due to cost control reasons, it is not possible to use more expensive dispersants. Most of the wetting dispersants that are anionized and non-ionized are now on the market. Their principle is low surface pressure, quickly wet pigment particles, and then through high shear force, such as dispersion machines, grinding machines, so that pigment particles form a semi-flocculation, or called controlled flocculation dispersion. If the viscosity of the coating is relatively high at this time, there will be no pigment anti-coarse and serious flocculation phenomenon, but if the viscosity control is not good, a long time, there will be problems; The advantages of this is: good overall performance, but also dispersed, less dosing, can increase the adhesion of the coating. But the point is that it is not a flocculation group, the high requirements of color-expanding paint is not suitable. Through research and practice, it is recommended to use dispersants that can solve flocculation in water-based coatings. The advantages of this is: good color display for pigment fillers, high brightness, good gloss.
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