High-efficiency dispersion technology and equipment for environmentally friendly water-based coatings

Paint is actually a product of modern industrial development, but it has a long history of development. With the emergence of polymer materials, people's daily life and industrial development has undergone a significant transformation, under the guidance of fine chemical products, the original paint quality has been significantly improved.
paint is a type of paint, the application range and category are showing greater development
china

. In recent years, the quantity of paint sales in the chemical industry output value has exceeded 5%, and showed a steady growth trend, which also shows that paint in the development and construction of the national economy plays an important role.1 Coating composition and category
1.1 film
film-forming material is mainly composed of two parts, respectively, polymer material and grease, is an important part of the coating coating surface. As the basis of coating composition, the physical and chemical properties of the film have a direct effect on the coating. The paint primer must have good attachment and rust resistance in order to be closely integrated with the paint, which needs to have good insulation and decorative properties. According to economic factors and practical requirements, film formations should be selected first, and then other components should be analyzed.
1.2 dispersed
normally, film-forming substances are relatively viscous and belong to polymer polymers. Organic solvent as a dispersion medium, with coordinated coating viscosity, so that the film dispersion into a liquid role, to ensure that the coating can be directly constructed and applied. After coating construction and film formation, organic solvents will evaporate into the atmosphere, and film-forming substances will form protective films on the surface of the object. The volatiles in the coating are mainly water and organic solvents, but organic solvents can cause environmental pollution after evaporation, and the amount of use should be strictly controlled.
1.3 Pigments and fillers
pigments and fillers, in the actual application process can not be filmed alone, need to use the relevant means to blend it with film-forming substances, coatings after curing into film. In other words, the application of coating film in pigments and coatings acts as an auxiliary substance.
paint can provide a variety of colors for coatings, with good decorative effect. In addition, pigments also play a good role in improving the anti-acid and alkali and chemical properties of the material membrane. Fillers, also known as body pigments, although the coloring effect is not obvious, but can effectively improve the performance of the coating, and reduce the cost of coating production.2 Environmentally friendly water-based coating dispersion technology and equipment
2.1 pigment and filler dispersion
coatings have a variety of categories, but the production principle is basically the same. Overall, the coating belongs to pigments, solvents, paint mixing system, under the action of coating, evenly applied to the surface of the object, curing after the formation of a film. It's relatively simple to say, but it's not easy. Color paint belongs to viscous paint material, mainly composed of solvents and additives, the whole system contains a variety of phase interface, different components are always in the state of interaction, and then the system stability is low, very easy to appear phase interface separation problems. However, color paint production needs to be in a relatively stable state, once the separation problem, color paint viscosity will be significantly affected, the paint after construction results are not ideal. Therefore, color paint is not only a simple mixing of different components, but should be dispersed into the paint structure by means of effective dispersion.
a broad sense, solids are distributed in liquid or gas states and are called dispersions. For coatings, dispersion mainly indicates that pigments are evenly distributed in the resin solution and are in a relatively stable system. Pigment dispersion in the coating is relatively cumbersome, basically can be divided into three stages, respectively, wetting stage, de-ionization stage and stabilization stage.
2.1.1 Wet Phase
Pigment particle surface in the production of coating applications, the most surface will certainly come into contact with moisture and air, the gap between different particles will also be filled with air. Pigments want to be evenly dispersed into the paint, the prerequisite is the need to apply paint instead of moisture and air, at the same time, on the surface of pigment particles to form a coating film. The process by which the paint replaces moisture and air and forms a coating film on the pigment surface at the same time is the moisture phase of the pigment.
2.1.2 De-ionization phase
pigments are dispersed in the paint, and it is not enough for the paint to come into contact only with the surface of the pigment particles, mainly because the pigments cannot be in a stable dispersion state. Therefore, this requires the application of external forces, pigment particles are decomposed, its volume into primary particles, increase pigment particles and paint base area. The process of restoring the pigment to the primary particles with the help of external force is called the de-ionization phase.
2.1.3 Stabilization phase
pigments want to be stable distribution in the paint system, mainly through the use of two kinds of processes, the two conditions are spatial position resistance stabilization and charge stability. Under normal circumstances, in the aqueous solution environment, pigment particle dielem constant is relatively high, the stability of the charge is very significant.
positive and negative ions of pigment particles gradually shift to the opposite solution after adsorption, which in turn forms a thin film of charged particles on the surface of the solution. The surface of a particle forms a double charge layer when the opposite particle charge is gathered, and this particle distribution is also known as a balanced particle. The double charge layer decreases in number with the increase in the depth of the solution. In the process of contact between the two particles, there is no charge rejection, will inevitably cause pigment particles charge redelocation, increase the rebuke between particles, the dispersion system can be in a stable state, this stage is also known as the stabilization phase.
2.2 Environmentally friendly water-based coating dispersion equipment
2.2.1 high-speed dispersion machine
high-speed dispersion machine, is the coating of many dispersion equipment in the structure of the simplest one, in the course of operation and sander combined as pigment premix equipment, in some cases, high-speed dispersion machine can also become a separate pigment dispersion equipment. The most critical part of the high-speed dispersion machine is the dispersed impant, the edge of the dispersed imperfle is curved and toothy, with a tilt angle of about 30 degrees, and each flank will produce a shock during operation. In fact, the material movements from the inside of the flank to the edge, which is a shearing effect. Paint material to and from the flank and edge, in the state of acceleration and deceleration, viscosity will gradually decline.
advantages of high-speed dispersion machine are: simple structure, practical operation and post-maintenance convenience, high production efficiency, along with the increasing category of high-speed dispersion machine equipment, and then the application of a wider range.
2.2.2 sander
sander was born in the late 1950s, the first application in China is in the 1960s. The sander itself is relatively small in size, can carry out continuous dispersion operation, high operating efficiency, and then has been widely used, at the same time, gradually replaced the ball mill in the paint.
grinder is mainly composed of five parts, namely, grinding cylinder body, dispersion disc assembly, motor, frame and spindle.3 conclusion
Environmentally friendly water-based coatings in the application, will not cause pollution to the ecosystem, has a good development prospects, in the paint industry share continues to increase. However, environmentally friendly water-based coatings in the actual production, pigment dispersion still take traditional dispersion technology and equipment, production efficiency is relatively low. This paper analyzes and studies the dispersion technology and equipment of environmentally friendly water-based coatings, understands the advantages of different dispersion technologies and equipment applications, and hopes to disperse pigments in environmentally friendly water-based coatings and provide high-quality technology and equipment assurance.