When choosing pigments for coatings, you must understand these 7 performance indicators

01 Pigment Color

The color of the pigment is due to the selective absorption of light of different wavelengths in the visible light by the pigment, and is affected by physical properties such as crystal shape, particle size and dispersion performance; the color of the pigment is also affected by the light shining on it. Cerulean Blue Pigment

For example, in the dark, the pigment does not show any color, the color in strong light is brighter than in dark light, and the same pigment under different light sources (such as sunlight, incandescent light, fluorescent light, etc.) can also show different color.

02 Tinting strength

The tinting strength of a pigment refers to the ability of a pigment to show shades of color when mixed with another pigment.

When the same color is adjusted, the stronger the tinting strength, the less the amount of color paste, the less the water resistance of the color paste coating and the less influence on the performance of the coating film.

Therefore, the same color, the quality of the products of different manufacturers will be very different. The strength of pigment tinting strength does not depend on its properties, but also on its degree of dispersion. The greater the dispersion, the stronger the tinting strength.

03Hiding power

The ability of the pigment in the coating film to cover the surface of the object to be painted, so that the substrate can be covered and revealed through the coating film.

The hiding power of pigments mainly depends on factors such as refractive index, ability to absorb light, crystal structure, and degree of dispersion, as well as its ability to absorb light irradiated on the coating surface. For example, carbon black can completely absorb the light shining on it, so its hiding power is strong. The hiding power of opaque color pigments also depends on their selective absorption of light.

The pigment is evenly dispersed in the base material, the particle size is small, the specific surface area is increased, and the covering power is also increased. However, if the size of the pigment particle size is equal to half of the wavelength of light, the light will Proceed through the particle without refraction, leaving the particle transparent.

The higher the crystallinity of the pigment, the stronger the hiding power. The hiding power of mixed pigments cannot be calculated according to the addition law of the hiding power of each component of the mixture. In fact, the hiding power of most mixed pigments is larger than the calculated value. Therefore, mixing the pigment and the filler in an appropriate ratio will not affect its covering power, and is conducive to reducing costs. The covering power of the coating is high, the brushing area is high, and the project cost is low.

Cerulean Blue Pigment

color pigment

04 Dispersion and adaptability

The so-called dispersibility of pigments refers to the ease with which the aggregated pigment particles are dispersed in the coating base material and the dispersion state after dispersion. It is affected by factors such as pigment properties, preparation methods, particle size and particle size distribution. .

The dispersibility of the pigment has a significant impact on the hiding power and tinting strength of the pigment, and also has an impact on the physical and chemical properties of the coating film.

Pigment compatibility issues, which are particularly important for emulsion-based architectural coatings. Due to the different types of pigments, the effect of pigments will also show different degrees, and the tendency of pigments is more obvious. The pigments are poorly dispersed in the paint and have poor matching with the paint, and the paint will have potential flocculation or even fading.

05 fineness

The fineness of the color paste is not as fine as possible, because pigments such as phthalocyanine blue and phthalocyanine green are themselves small molecular pigments. The fineness is too small, the particle size difference is large, the dispersibility is poor, and the compatibility with coatings is not Well, the cost of color correction will increase, and it will also lead to floating colors.

pigment

06 Lightfastness Weatherability

The color of pigments will change to varying degrees under the action of light, and the color will gradually become darker under long-term sunlight exposure, and some pigments will also produce chalking phenomenon under the action of ultraviolet rays in sunlight. The exterior wall coating should use pigments with good light resistance and weather resistance. Generally, the light resistance is greater than 7~8 grades, 8 grades are good, and the weather resistance is more than 4~5 grades, and 5 grades are good.

07 Acid and alkali resistance

The acid and alkali resistance of the pigment is also an important performance index for its use in architectural coatings.

Some pigments are not resistant to acid or alkali, so they cannot be used in acidic or alkaline coatings, and the resulting coatings are not suitable for use in acidic or alkaline environments, so customers should pay attention to the selection of coatings and latex paints.