Frequently asked questions about color paste application! ! !

Frequently asked questions about color paste application! ! !

1

The color paste is added to the paint, and the color floats on the surface

reason

1) The surface tension difference between the color paste and the paint is too large

Coatings generally use anionic or ionic polyelectrolyte dispersants, while color pastes generally use non-ionic or partly anionic dispersants, so that white pigments and colored pigments can absorb different wetting and dispersing agents on the surface, and have different properties. Surface Tension.

2) Poor compatibility between color paste and paint

The emulsifier outside the emulsion particles is not compatible with the surfactant outside the pigment and filler particles, resulting in flocculation of the pigment.

3) The hydrophilic-lipophilic balance between the color paste and the paint does not match

Oleophilic substances have a low surface tension at the lipophilic end and are relatively easy to float to the surface.

4) The influence of thickener

Some associative thickeners with strong pseudoplasticity have great affinity with surfactants with large HLB values, which makes them desorb on the surface of pigments, resulting in aggregation and flocculation of pigments, resulting in floating and blooming.

Solution

The best way to control floating color is to select appropriate wetting and dispersing agent, adjust particle surface properties, and adjust its movement balance.

If colored pigment flocculation, floating white, pigment flocculation floating color, wetting and dispersing agent can be used to relieve flocculation, improve particle surface properties to prevent or control floating color, several floating color phenomena can be changed in the process of controlling floating color , controls the floating color. If the floating color is the color of the color paste, it means that the HLB value of the paint is relatively large and relatively hydrophilic. Adding lipophilic and low-polarity additives during the preparation of the base paint reduces the HLB value of the paint; if the floating color is white, it means The HLB value of the paint is relatively small and relatively lipophilic, and hydrophilic additives are added during the preparation of the base paint to increase the hydrophilicity of the paint.

In some systems, it can resist the floating color of the coating film. An anionic wetting and dispersing agent is added to the finished paint, which is adsorbed on the surface of carbon black or organic violet pigment particles, which improves the surface properties of the pigment particles and enhances the polarity. The non-polar and weakly polar particles have the same polarity as the white particles, and have the same degree of adsorption and flocculation as the polymer, so they have the same movement ability during the drying of the coating film and control the floating color. Use surfactants that can reduce surface tension strongly, such as silicone surfactants, to migrate to the surface to form a single molecular film during the drying process of the coating film, balance the surface tension and control blooming; however, floating color may still exist.

Add some additives that can produce thixotropic structure, such as kaolin, or silicon dioxide, to form a network structure in the paint film, prevent pigment separation, control pigment flocculation, sedimentation and Bernard vortex flow, and alleviate Prevents floating or blooming.

2

Obvious roller marks appear in the paint on the wall

reason

1) Uneven thickness during brushing operation

2) Construction without wet joint

3) Compatibility issues

4) Insufficient additives in latex paint

5) The amount of emulsion in the latex paint is insufficient

6) The wall is not completed at one time

Solution

Mainly for compatibility issues:

1) Mechanical dispersion (color paint)

The color of the paint can be displayed under the condition of a certain mechanical force dispersion.

2) Add wetting agent (color paint)

After adding wetting agent, the color becomes much darker, the color difference between finger grinding becomes smaller, and there is no obvious brush mark after brushing the board.

3) Adjust the paint formula (base paint)

Change the wetting, dispersing and thickening system of the paint to solve the compatibility problem between the paint and the color paste.

3

There are obvious rain marks on the surface of the paint after the rain

reason

1) basePoor paint water resistance (emulsion is too hydrophilic, excessive wetting agent or too much hydrophilic additive)

2) The water content of the substrate is too high or the ambient humidity is too high

3) Sealed primer, did not achieve the effect

4) Rinse with water before the coating film is completely dry

5) There are too many residual additives in dark paint

Prevention methods

1) Try to use as little surfactant as possible, and try to use silicone to reduce hygroscopicity.

2) Use fluorine-modified resins or additives to enhance water repellency and stain resistance.

3) Use emulsion with good water resistance.

4) The surface is painted with varnish.

4

After the rain, the surface of the paint has obvious color fading

reason

1) The surface drying time of the paint film is insufficient, and it will encounter rainwater less than 2 hours after construction.

2) The PVC concentration of the paint is too high, that is, 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 the emulsion.

2) Choose an emulsion with good water resistance.

5

After a period of time, the wall surface obviously fades (blooming)

reason

1) The emulsion content of the paint is low.

2) The water resistance of the coating is not good.

3) Improper selection of color paste.

4) If the paint film is pulverized in dark colors, the color will also become lighter.

5) Color migration (migration to the inside).

6) The drying rate is poor due to conditions such as the sun exposure temperature of the construction project.

7) The flatness is not enough, and under the influence of gloss, it causes poor vision in the distance.

Solution

1) Increase the emulsion content in the paint.

2) Choose color paste with good weather resistance.

3) Engineering condition control.

6

The desired color cannot be retrieved

1) The content of titanium dioxide is not suitable (colors with poor hiding power cannot be displayed).

2) Improper selection of colorants (some colors cannot be replaced by other colorants).

3) Color migration.

Solution

1) Select the coating with appropriate titanium dioxide content.

2) Choose color paste with good compatibility.