Introduction to the use of water-based color paste!

Introduction to the use of water-based color paste!

1. Introduction to water-based color paste

Water-based color paste refers to the formation of organic or inorganic pigments under the wetting and dispersion of surfactants (water-soluble resins can also be added), which are uniform and stable, and have certain fluidity or thixotropic fluidity. , a concentrated pigment paste with strong tinting strength. There are two types of water-based color paste systems: one is a resin-free system with high pigment content; the other is a resin (general resin, other single resin) system with low pigment content. Among them, the former has high pigment concentration, strong tinting strength, good color development, good compatibility, and thixotropic fluidity. Generally, it does not cause color floating and blooming. The selection of additives is reasonable and has versatility. The latter has a relatively low pigment concentration, but it has good tinting strength, good color development, and relatively stable fluidity and viscosity. The system contains resins, and the compatibility needs to be tested, otherwise it will easily cause the paint to float and bloom.

、Main technical indicators of color paste

1. The quality of the toner in the color paste (mainly depends on its international pigment number)

International Pigment Number: simply understood as a uniform pigment code formulated according to the different molecular structures of the toner, the pigment number determines the light resistance (weather resistance) and chemical resistance (acid and alkali resistance) of the color paste, and at the same time It also determines the approximate hue of the color paste. Due to the different production processes of various color paste companies, there may be slight differences in the color phase of the color paste.

Common international pigment code list

Color CIPigment English name Chinese name

Titanium White6DioxideTitanium

Iron Black Black11IronOxideRed Iron Black

Carbon black Black7CarbonBlack carbon black

Ultramarine Blue29Ultramarine

Red168AntharuinoreRed Anthraquinone Red

Red112MonoazRed monoazo red / acetamide red

Positive red Red254DPPRedBODPP red

Coral red Red255DPPRedBOCoralDPP coral red

Iron Red Red101IronOxideRed Iron Red

Light yellow Yellow1 monoazo yellow

Bright Yellow Yellow3MonoazYellow monoazo yellow

Bright yellow Yellow109Isoindolinone

Iron Yellow Yellow42IronOxideYellow Iron Yellow

Yellow74MonoazYellow Monoaz Yellow/Aramid Yellow

Dark Yellow Yellow83DisazoYellow Disazo Yellow

Bright yellow Yellow97Monoazo

Yellow138QuinolineYellowQuinoline Yellow

中黄Yellow110Isoindolinoneisoindolinone yellow

Golden Yellow153NickelComplex

Golden yellow Yellow154BenzimidaZolone benzopyrazolone yellow

Sapphire Blue15:1PhthalocyanineGreen Phthalocyanine Blue

Blue15:3PhthalocyanineGreen Phthalocyanine Blue

Blue15:4PhthalocyanineGreen Phthalocyanine Blue

Green Green36PhthalocyanineGreen Phthalocyanine Green

Green Green7PhthalocyanineGreen Phthalocyanine Green

Violet23OxazineViolet Dioxazine Violet

Violet19QuinacridoneViolet quinacridone purple

Orange red Orange5 dinitroaniline orange

Orange43

Orange73DPPOrangeDPP orange

Iron Brown6IronOxideBrown Iron Brown

The international pigment number is an important basis for matching the product models of different color paste companies one by one. When we test the quality of different brands of colorants, we should choose colorants of the same pigment number from different manufacturers for comparison. Any colorant company must provide customers with the international pigment number of its colorant. Fully understanding the quality of toner is the most important basis for latex paint manufacturers to choose colorants for different application fields (such as interior and exterior wall paints).

2. The coloring strength of the color paste (coloring power)

Tinting strength refers to the number of grams of a certain color paste used when adjusting 100 grams of white latex paint containing titanium dioxide to a standard color depth of 1/25. The less the color paste is used, the stronger the coloring power. For the comparison of water-based colorants, tinting strength is an important indicator, which reflectsThe color concentration, color development performance and flocculation of pigment dispersion of color paste. The stronger the tinting power of the color paste, the less the amount of color paste used in toning, the smaller the impact on the performance of the coating film, and the lower the color toning cost.

3. Color difference ΔE

The stability and color reproducibility of the color paste are mainly reflected in the two aspects of tinting strength and color difference. The color difference of the color paste includes the color difference between different production batches of the same color paste and the color difference between different packages of the same batch. The size of the color difference is represented by ΔE, including color hue, lightness, and saturation. Its calculation formula is as follows:

ΔE = (Δa2+Δb2+ΔL2)1/2 The color difference of the color paste affects the accuracy of toning and the stability of the toning formula.

In this regard, there are still some gaps between domestic and imported colorants. For example: ΔE<0.6 of Flexobritec series factory color pastes of Degussa company; ΔE<0.5 of COLORTREND888 series mechanical color pastes. Color paste is generally not up to this level.

4. Light resistance and weather resistance of color paste

The light and weather resistance of the color paste is tested through outdoor exposure (for example, Florida in the United States, Turpan in my country and other places have exposure fields), but the actual outdoor exposure time is too long, and most of the general color paste performance tests are now through instruments. Equipment and other simulation tests. Light fastness test: exposure under xenon lamp, measured by blue wool ruler, represented by grade 1-8, grade 8 is the best, grade 1 is the worst.

Weather resistance test: use ATLAS weathering instrument, regularly expose to xenon lamp and spray with water, expose for 500 hours, the color difference is represented by ISO gray scale 1-5, 5 is the best, 1 is the worst. The color paste for exterior walls needs to meet the two conditions of light resistance level 7 or above and weather resistance level 4 or above.

5. Pigment content of color paste

Pigment content is for reference only and cannot be used as an index to evaluate the performance of color paste. The tinting strength of the color paste is not directly proportional to the pigment content. With the same pigment content, the tinting strength is also very different with different fineness. In order to ensure the stability of the coloring power of the color paste, the pigment content of the color paste varies within a certain range, and the value provided in the color paste information is a typical reference value.

6. The fineness of color paste

The fineness is an intuitive index reflecting the color dispersion effect and storage stability of the color paste. Generally, for the same pigment paste, the smaller the particle size, the larger the specific surface area, and thus the larger the hiding power, and the higher the tinting strength; the smaller the fineness, the higher the gloss, and the better the dispersion effect and storage stability. the better. Of course, the fineness of the color paste is not as fine as possible, because when the particle becomes smaller and its specific surface area increases, the absorbed light energy increases and the degree of damage increases, resulting in a decrease in its weather resistance; and the particle size is too large When the paint film is dry, with the precipitation of water, the color paste migrates to the surface together, which may easily cause inaccurate color matching and wall color difference.

7. Compatibility of color paste and paint

Finger grinding method Take 100 grams of white paint, add 2-3 grams of color paste to be tested, stir well, and apply it on the surface of the object to be coated. After the film is completely dry, observe whether there is a color difference between the place rubbed with your fingers and the place that has not been rubbed. If the difference is large, the compatibility of the color paste with the tested paint is not good. The paint prepared with this color paste Easy to produce floating color phenomenon. If the color is the same, generally there will be no floating color phenomenon.

When choosing a color paste, the above factors should be considered. Other conditions can basically be met by each brand of color paste with little difference. Of course, the choice of color paste should also be considered from the perspectives of economy and environmental protection. For example, the interior wall color paste can choose the color paste with poor weather resistance. At the same time, try not to choose the color paste containing heavy metals such as chrome yellow for the interior wall. , amines, etc.