Application of solvent-based oily color paste and color mixing method of paint color paste
Solvent-based oily general-purpose color paste generally use synthetic resins as carriers, such as aldehydes and ketones resins, acrylic resins and so on. There are also some resin-free or similar plasticizer system.
Selection of general-purpose color paste attention to the following points:
1, whether adding a certain concentration has an effect on the gloss.
2, whether there is an effect on compatibility, such as pigment flocculation, solvent insoluble. Whether the solvent in the paint has side effects on the resin of universal color paste. For example, aldehydes and ketones resin is not very good due to alcohol resistance.
3、Is there any effect on the viscosity. Some of the viscosity requirements of higher varieties. For example, nitro lacquer. Whether the viscosity has a significant impact.
4, temperature resistance is achieved, or whether the yellowing resistance is reliable.
5, aldehydes and ketones resin is not very good due to aldehyde resistance, generally not recommended for alcohol tolerance test coatings, such as some special wood paint, plastic paint and so on.
6, aldehydes and ketones resin temperature resistance is poor also makes its application has been partially restricted, such as some baking paint (drying temperature > 150 degrees) should be tested for solvent-borne coatings on the film-forming properties and yellowing resistance of performance.
Solvent-borne coatings are more likely to use the original color paint-based, color paste as a supplement to the color mixing method, why?
1, solvent-borne coatings using a variety of environmentally friendly resins and solvents is very much, the cost pressure is also greater, and the requirements of gloss and other requirements than the sex of the coating requirements are much higher, so the general solvent-borne coatings are mainly used in the original color paint-based color mixing, adding part of the general-purpose pulp color mixing.
2, solvent-based architectural coatings are generally acrylic resin as a film-forming material, the selection of a large number of fillers and part of the titanium dioxide to do the aggregate, the color is also more light-based, which is a more special category.
Light color : the total amount of color paste is less than 1%, and the black paste is less than 0.5%.
Medium and dark colors: the amount of color paste used is between 1% and 3%.
Dark colors : more than 3% (covering ability of 95% or more)
Note: Determine the main color, but it does not mean that the main color paste add more. Consider the inorganic category first, then consider the organic category.
When matching medium and dark color paint, reduce the amount of titanium dioxide to reduce the achromatic power and improve the coloring power. When mixing especially deep colors, use white paint with titanium dioxide content close to “0”. Especially bright, bright color selection of emulsion amount of more.
If there are many kinds of color paste, the color will be grayish. On the contrary, if the color paste is used in fewer types, the color will be brighter and better saturated.
1. The coloring strength of the color paste (coloring power)
The coloring strength is an important index, which reflects the color concentration of the color paste, color spreading performance and pigment dispersion flocculation. The data is measured by the number of parts of pigment paste needed for the color has reached 1/25 of the international standard depth (ISD), the smaller the value, the higher the coloring power. The value represents the number of grams of pigment paste needed to be added to the white base paint: in latex paint – white base paint with 25% titanium dioxide content (1/25ST).
2. Compatibility of the color paste (color spreading performance – finger study method)
The compatibility of the color paste with the used system is the key to the floating color of the color paint, flocculation and some surface defects of the paint film. If the fineness of the color paste is not enough, the dispersing performance is not good all lead to the color paste color spreading is not good, will affect the reproducibility of the color paint.
3. Dispersing performance of color paste (degree of flocculation)
The dispersion performance of color paste is not good, the pigment flocculent in the color paste and the base material in the white pigment, filler particles of the migratory difference is easier to reflect, this difference often makes the pigment flocculent is no longer uniform distribution, when the film due to the film in the temperature, density and surface tension of the internal tiny difference, the pigment flocculent and the base of the paint naturally involved in the movement, pigment flocculent and then separated, resulting in floating color and hair flower. If the dispersing performance of the color paste is good, it can avoid the generation of floating color and blooming.
4. Light resistance and weather resistance of color paste
Light resistance: Grade 1 is the worst, Grade 8 is the best.
Weather resistance: Grade 1 is the worst, Grade 5 is the best.
5. Pigment content of color paste
The coloring power of color paste is not simply proportional to the pigment content. The same pigment content. The coloring power of color paste differs greatly according to its fineness.
6. Fineness of color paste
Fineness is an intuitive index reflecting the coloring power dispersion effect and storage stability of the color paste. Generally for the same pigment color paste, the smaller the particle size, the larger the specific surface area, and thus the covering ability is also increased, the higher the coloring power; the finer the fineness, the higher the luster, the better the dispersion effect and storage stability. Of course, the fineness of the color paste is not the finer the better, because when the particles become smaller, its specific surface area increases, the absorbed light energy increases, the degree of destruction also increases, resulting in a decrease in weather resistance; and particle size is too small in the paint film drying, along with the precipitation of water, the color paste together with the migration of the surface, easy to cause the color is not allowed to match the color and the wall color difference.
7. Acid and alkali resistance of color paste
8. The following factors must be considered for external use: a. Light weathering resistance; b. Acid and alkali resistance; c. Compatibility with the use of the system; d. Tinting strength, hiding power and color spreading; e. Match between the color paste and the color paste quality control; f. Storage stability of the color paste.
