Introductory color mixing techniques and the choice of color paste
Water-based color paste refers to the organic, inorganic pigments, surfactants dispersed in aqueous media after crushing to form a stable pigment suspension.
Inorganic color pastes: most of them are iron oxide-based; they are excellent in acid and alkali resistance, weather resistance and light resistance. For example: Y42 iron yellow, iron black, R101Y/R101V iron red.
Organic color paste: organic synthetic; color paste unit price is relatively high, part of the color paste of the light weathering performance is low; in accordance with the requirements of the order; pay attention to the color paste with the choice. y74\83 and R112 and other pigment number of the same color paste varieties are not recommended to be used in the exterior wall; in the color paste to achieve the amount of 4% to be added to be used in the exterior wall. Consult the technical department immediately for specific application.
For example: R254/112 red, O73 orange, BK7/6800HT carbon black, Y74\154\83\110 yellow, B153 phthalocyanine blue, G7 phthalocyanine green, V23 purple, R122 rose, titanium dioxide (titanium dioxide color fading power, play a role in covering)
Color mixing application notes:
① Under the condition of guaranteeing the covering power, try to reduce the cost. That is, reduce the amount of color paste, but can not unlimitedly reduce the amount of color paste
l The ratio of the color paint is more than 0.95, which can be judged as qualified in terms of covering power.
l The deeper and more vivid color paint should be tested for constructability: the dry film color difference between two and three times of rolling paint is not big (experience judgment). Not included in the quality control assessment; but can be used as a reference.
② Avoid floating color, blooming and other paint diseases brought about by (consider the content of emulsion, titanium dioxide)
Finger research method: take 100 grams of white paint, add 2-3 grams of color paste to be tested, fully stirred, coated on the surface of the coated object, to be about to condense, with a finger to grind the surface layer of the film part of the paint film to be dry, observe the finger research and rubbing and not rubbing the place whether there is a difference in color, such as the difference is large, then the color paste is not good with the compatibility of the test coatings, so the paste of paint mixing out of the paint is prone to floating color phenomenon. If the color is the same, generally will not produce floating color phenomenon.
Color system: 1. iron oxide system 2. blue-gray system 3. warm color system
Light color : the total amount of color paste is less than 1%, black paste is less than 0.5%.
Medium and dark color: the amount of color paste 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 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, thus the covering ability is also increased, the higher the coloring power; the smaller the fineness, the higher the luster, the higher the dispersion effect.
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