Color Paste Application Frequently Asked Questions!!!
Paint technology problems to find paint old workers
1
When color paste is added to paint, the color floats on the surface.
Reason
(1) The difference in surface tension between color paste and paint is too big.
Paint generally use anionic or ionic polyelectrolyte dispersant, while color paste generally use non-ionic or partially anionic dispersant and use, so that white pigment and colored pigment surface adsorption of different wetting dispersant, with different surface tension.
(2) Poor compatibility between color paste and paint
The emulsifier outside the emulsion particles is not compatible with the surfactant outside the color and filler particles, resulting in flocculation of pigments.
(3) Mismatch of hydrophilic and lipophilic balance value between color paste and paint
The surface tension of the lipophilic end of the lipophilic substance is small, and it is easier to float to the surface.
4）Influence of thickening agent
Some pseudo-plasticity and strong binding thickeners have great affinity with surfactants with large HLB value, which makes them desorb on the surface of the pigment, causing the aggregation and flocculation of the pigment, and generating floating color and florid.
Solution
Choosing suitable wetting and dispersing agent, adjusting the surface property of the particles and regulating the balance of their movement is the best way to control the floating color.
Such as colored pigment flocculation, floating white, pigment flocculation floating color, can use wetting and dispersing agent to alleviate the flocculation, improve the particle surface properties to prevent or control the floating color, in the process of controlling the floating color several floating color phenomena can be transformed into each other to control the floating color. If the floating is the color of the color paste color, the HLB value of the paint than large, more hydrophilic, the basic paint preparation process to add oleophilic low-polarity additives to reduce the HLB value of the paint; if the floating color is white, the HLB value of the paint is relatively small, more pro-oleophilic, the base of the paint preparation process to add hydrophilic additives, increase the hydrophilicity of the paint.
Certain systems can be anti-film floating color, add anionic wetting and dispersing agent in the finished paint, adsorption on the surface of carbon black or organic violet pigment particles, improve the surface properties of the pigment particles, enhance the polarity of these non-polar weakly polar particles with the same polarity as the white particles, and the polymer has the same degree of adsorption of flocculation, and thus in the drying of the film in the movement of the film is comparable to the ability to control the floating color. Selection of surfactants that strongly reduce surface tension, commonly used silicone surfactants, so that they migrate to the surface during the drying process of the film to form a single molecular film, balancing the surface tension and control of bloom; but the floating color may still exist.
Add some additives that can produce thixotropic structure, such as kaolin, or silica, to form a network structure in the paint film to prevent the separation of pigments, to control the pigment flocculation, sedimentation, and the flow of the Benedict spinning nest, to alleviate the phenomenon of floating colors and flowers to prevent floating colors or flowers.
2
Obvious roller marks appear in the roller coating of color paint on the wall.
Reason
(1) Uneven thickness during painting operation.
(2) Construction without wet joint
3）Compatibility problems
4）Insufficient amount of auxiliary agent in emulsion paint
5）Insufficient amount of emulsion in latex paint
6) The wall is not constructed at once
Solution
The solution is mainly for the compatibility problem:
1) Mechanical dispersion (color paint)
Color paint color can be shown under certain mechanical force dispersion.
2) Adding wetting agent (color paint)
After adding wetting agent, the color becomes much darker, the color difference of finger research becomes smaller, and there is no obvious brush mark after brushing the board.
3）Adjust the paint formula (base paint)
Change the wetting and dispersing thickening system of the paint to solve the problem of compatibility between the paint and the color paste.
3
There are obvious rain marks on the surface of color paint after rain.
Reason
(1) Poor water resistance of base paint (emulsion is too hydrophilic, too much wetting agent or too much hydrophilic additives)
(2) The water content of the substrate is too high or the humidity of the environment is too high.
3）Closure primer, not to achieve the effect
(4) The coating film is not completely dry before being flushed with water.
(5) Too much residue of additives in dark-colored paint
Preventive measures
(1) Try to use less surfactant, try to use silicone, reduce moisture absorption.
(2) Use fluorine modified resin or additives to enhance water repellency and stain resistance.
(3) Use emulsion with good water resistance.
4）Paint the surface with varnish.
4
Apparent color loss on the surface of color varnish after rain.
Reason
(1) Insufficient time for surface drying of paint film construction, less than 2 hours after construction in the rain.
(2) The concentration of PVC is too high, i.e. the emulsion is too low or the filling amount is too high.
3) The water resistance of the paint film is extremely poor.
Solution
1) Increase the content of emulsion.
2) Select the emulsion with good water resistance
5
Apparent fading of wall color after a period of time (blooming)
Cause
1) The emulsion content of the paint is low.
2) Poor water resistance of the paint.
3) Improper choice of color paste.
4) Dark color will also show lighter color if the paint film is chalked.
(5) Color migration (to the internal migration).
(6) Poor drying rate due to conditions such as sunlight temperature of construction works.
(7) Insufficient flatness, under the influence of gloss, resulting in visual difference from a distance.
Solutions
1) Increase the emulsion content in the paint.
(2) Select the color paste with good weather resistance.
3) Engineering conditions control.
6
Unable to mix the required color
Reason
(1) Inappropriate titanium white content (colors with poor hiding power cannot be exhibited).
2）Inappropriate choice of color paste (some colors can not be replaced by other color pastes).
3) Color migration.
Solution
1）Choose the paint with suitable titanium white content.
2) Choose color paste with good compatibility.