wetting dispersing aids application

 Application of wetting dispersing aids
The base of the pigment in the paint wetting and dispersing is an important process in the manufacture of paints, paint wetting dispersing additives on the quality of a great movie
Rang. Wet grinding and dispersion of dispersing agents can shorten the time and reduce energy consumption, to ensure a steady state dispersion coating, the coating of the many performance plays a decisive role.
Pigment dispersion is a group of the  aluminium distearate secondary particles and agglomerates of aggregates broken into finer abrasive particles or primary particle size, it
Become a stable dispersion suspension. Yan moist grain: It is the process of changing the surface properties of the pigment, the pigment surface remove adsorbed water and air, to change its polarity, lower liquid / solid interface between the tension and increase the affinity for pigments and paints. Humectant is in the role of this phase additives. Wetting agent is to improve the effectiveness of the pigment dispersing surfactant wetting agent. It
Pigment surface has a strong affinity. Orientation can be adsorbed on the surface of the pigment, pigment surface adsorbate substituted: water and air. Enhance the affinity of paints and pigments, pigment in paints shorten grinding dispersion time. Because the pigment surface run process is actually a replacement project pigment wetting agent should be and therefore has a strong affinity for the pigment. The dispersion process, formed by mechanical grinding paint pigment fine particles and form a uniform suspension, the external force, to maintain a stable dispersion state is usually referred to as dispersed phase, also known as stabilization phase, the dispersant is at this stage play The additive effect. Dispersing agent is able to maintain a stable dispersion coating to improve the surface-active substances. Adding a dispersing agent in the coating can be pulverized into fine particles adsorbed on the pigment surface, constituting an adsorption layer, the charge-generating steric repulsion effect of the air to prevent re-dispersed pigment particles form harmful flocculation, can be maintained in a stable suspension system state. Dispersant of general
Large child, and can form a thick adsorption layer. Dispersant if used properly, can not only prevent pigment settling, the paint has
Good storage stability, but also to improve leveling, prevent pigment blurs to obtain a uniform color coating to improve
Coloring pigment strength, opacity, gloss increase the  film, but also reduce the viscosity of the paste, increase the  liquid stabilizer pigment grind paste
Content, improve grinding efficiency and achieve savings in manpower and energy effects.
1, a wetting dispersant, additive manufacturers have introduced general, but adding the scope and amount of the coating should be based on
Species and required to make specific decisions. To do this, we must first understand the characteristics of the resin used, and secondly to grasp the characteristics of the pigment surface, in particular acid resistance, specific surface area of ​​the size, shape, etc., to set the added amount, generally higher than the amount of surface area a little more, a small is less. If insufficient amount, the pigment surface spare too many points, could easily lead to flocculation, be counterproductive. Such as: the specific surface area is small, the amount of excess, the formation of micelles in the paint, it will affect the water resistance of the coating. So be sure to use suitable screening test must be repeated. 2, a wetting agent added dispersing procedure: pigment wetting dispersant is generally added when the ingredients to make the grinding and dispersion of the pigment surface adsorption, to achieve the desired purpose. If the compound used in the non-polar hard dispersed pigment, preferably blended in a small amount first additive resin solution and then mixed with the pigment soaked, so that the application would be more effective.
Dispersing pigment in the paint pigment in the dispersion process is more complicated, but at least through three processes, namely wet depolymerization (dispersion) and stabilized.
Providing paint pigment production, the vegetable stearic acid   production of the pigment particles formed are subtle, and its particle size is generally in between 5nm to 1um, the dispersion system can be formed easily.
But the paint pigment plant put into production, mostly in the original-sized particles, agglomerates and aggregates mixtures exist. Primary-particle: a pigment formed in the manufacturing process of associating a single crystal or crystals is relatively fine grain size. Agglomerates: the original sized particles connected edges and corners, a combination of the structure is relatively loose, large particle group. Aggregates: a primary-particle combination of two-sided, or the growing crystal surface together, the structure is compact, large particle group.
Most of the pigment agglomerates of Lu cake drying and subsequent formation of a dry mill.
Aggregates of pigment manufacturing process precipitate formed during the curing. Agglomerates and aggregates secondary particles as pigments together. 1, pigment wetting:
Production of the pigment used in paints are generally adsorbed surface layer of air and water, the voids between the particles are filled by air, dispersing the pigment in the paint the most important prerequisite is the need to use paints instead of air and moisture, and exposure of the pigment the formation of a new layer on the surface of coated film, which instead of air and moisture with the paints and coating film formed on the surface of the pigment in the process, referred to as pigment wetting process. 2, the pigment depolymerization (dispersion): In the dispersion process, only the surface of the secondary particles is not enough to wet paints, because such a large size, small surface
Group product of pigment particles can not meet the requirements and maintain a film forming paint liquid paint a stable dispersion state.
Must therefore be subjected to external mechanical forces (shear forces primarily) deaggregation these large particles, to restore back to the original level at or near the particle size to small particles form a large surface area exposed to the paint and so that all surfaces are exposed by wet paints. This means the applied mechanical force, the pigment agglomerates and aggregates restored or nearly restored to the original level of particles or depolymerization process called dispersion process called. Pigment in the paint in the paint manufacturing process depolymerization is the main, the most energy consuming processes. Depolymerization can paint the outer
To mechanical force, usually by grinding and dispersion we normally use equipment, such as a sand mill, ball mill, three-roll machine, high speed disperser and two roll machine generated. As a dispersion medium in order to create a liquid vehicle for the pigment (filling) material particles penetrate the surface of the conditions necessary to color (fill) material aggregates and agglomerates can be applied to promote its breakdown external mechanical force, the color (fill) depolymerization material particles, it is better to paint the wetting liquid, which requires grinding and dispersion equipment. Paint the polishing slurry, the pigment particles depolymerization process, not only can be sufficiently liquid so that wet paint color (fill) material particle surface to improve the stability of the millbase, and with a higher level of pigment dispersion, coloring pigments, cover will be a corresponding increase in strength, gloss and other paint film performance is also improved. So the selection of an efficient grinding and dispersion device, can greatly improve the dispersion of pigment in the paint level, thereby improving the millbase while reducing the amount of pigment stability, improve the quality of paint and coatings. 3, the stabilization: depolymerization has been wetted pigment particles distributed to a large number of paints continue to go, so there is enough paint coated on the periphery of pigment particles, and isolated from one another, thereby reducing the pigment particles attraction between avoid the phase between the pigment particles
Contact with each other, such that each has to be gathered and the solution of the pigment particles are moistened sufficiently thick, continuous, non-volatile dispersion of film-forming material is permanently open, the dispersion in the absence of the control of the applied mechanical force, pigment particles does not occur again coalesce into large particles in the process, called the stabilization process, the stability of the pigment dispersion obtained, the ultimate goal is the production of paint. Thus, the dispersion of pigment in the paint is wet, and stabilization depolymerization process three major components.
But, in fact, these three processes are not completely separate, but simultaneous and alternating conducted. For dispersing the pigment in the paint dispersion is formed, the relationship between the three: a wet basis, in order to more fully depolymerization wetting, and to achieve steady state of the ultimate goal.
If the pigment is dispersed in the paint well, to reach a relatively stable state, then had been dispersed pigment particles likely will re-close and gathered into large particles, forming what we call a pigment floc flocculation of pigments is distributed among the inverse process. Floc pigments and aggregates and agglomerates, although the original-sized particles made of large particle coalescence particle group, but the floc and the latter are essentially different, although it still paints the surface of the package cover, paint particles have been filled the gap, the pigment aggregates and agglomerates the surface of the cladding is air and water, the gap is filled by air, but the micro-flocculation state, in the production of coatings as well as its the use of the Department.