Guide to the use of water-based color paste dispersants

In the colorful world of water-based products such as paints and inks, water-based color paste dispersants play a key role. It ensures that the pigment is evenly dispersed in the water-based system, allowing the product to present stable and brilliant colors. The following is a detailed introduction to how to use water-based color paste dispersants correctly.

1. Preliminary preparation

Choose a suitable dispersant: There are many types of water-based color paste dispersants on the market. You should choose according to the characteristics of the pigment used (such as organic pigments or inorganic pigments), the water-based system (such as acrylic emulsions, polyurethane dispersions, etc.) and the desired dispersion effect. For example, for organic pigments, you may need to choose a dispersant with a specific anchoring group to enhance the adsorption of pigment particles.

Determine the amount of dispersant: This usually needs to be accurately determined through experiments. Generally, refer to the recommended addition range provided by the dispersant supplier, which is generally between 1% and 10% of the pigment mass. For example, in the preliminary test, if 100 grams of pigment is used, you can try to add 1 gram of dispersant first, and then adjust the amount according to the dispersion effect.

Prepare the equipment: Common equipment includes high-speed dispersers, stirrers, etc. High-speed dispersers are suitable for processing large batches and high dispersion effects; small stirrers are suitable for laboratory tests or small-scale production. Make sure the equipment is clean and free of impurities to avoid affecting the dispersion effect.

2. Steps for adding dispersants

Pre-dispersion: In a clean container, first add an appropriate amount of water, turn on the stirring equipment, and run at a low speed (about 200-300 rpm). Slowly add the weighed water-based color paste dispersant to the water, and continue stirring for 5-10 minutes to make the dispersant initially evenly dissolved in the water to form a dispersant solution. This step allows the dispersant to play a better role in the subsequent process.

Add pigment: Maintain the stirring state and slowly add the pigment to be dispersed to the above dispersant solution. The addition process should be uniform and slow to prevent the pigment from agglomerating. After the pigment is added, gradually increase the stirring speed to 800-1200 rpm and stir for 15-30 minutes to allow the pigment to fully contact the dispersant and initially disperse.

High-speed dispersion: For applications with higher requirements, transfer the mixed liquid to a high-speed disperser. Set the high-speed disperser speed to 1500-3000 rpm and disperse for 15-60 minutes, depending on the type of pigment and the difficulty of dispersion. For example, inorganic pigments may be relatively easy to disperse and can be dispersed at high speed for 15-30 minutes; while organic pigments may require 30-60 minutes. During the high-speed dispersion process, the dispersant will use strong shear force to penetrate into the pigment aggregates and break them into fine and evenly distributed particles.

Detection and adjustment: After the dispersion is completed, take a small amount of the dispersion for testing. Common detection methods include particle size analysis, which measures the particle size distribution of pigment particles by laser particle size analyzer. Ideally, the particle size should be uniform and small, generally between 100-500 nanometers. You can also observe the appearance of the dispersion. If the color is uniform and there is no obvious particle precipitation, it means that the dispersion effect is good. If the dispersion effect is not good, add dispersant appropriately and repeat the high-speed dispersion steps until a satisfactory effect is achieved.

3. Precautions in use

Temperature control: The temperature during the dispersion process should not be too high or too low, and is generally controlled at 20-40℃. Too high temperature may cause the dispersant to decompose and fail, and the pigment performance may also be affected; too low temperature will reduce the dispersion efficiency and extend the dispersion time. For example, when the temperature is high in summer, the dispersion container can be cooled by cooling equipment; when the temperature is low in winter, the raw materials can be preheated appropriately.

Avoid impurities: The entire operation process should be carried out in a clean environment to prevent dust, oil and other impurities from mixing. Impurities may react with dispersants or pigments, interfere with the dispersion effect, and cause problems such as color spots and color differences in the product.

Storage conditions: Unused water-based color paste dispersants should be stored in a sealed manner and placed in a cool and dry place to avoid direct sunlight. The storage temperature is generally between 5 and 30°C to prevent the dispersant from deteriorating due to environmental factors and affecting the subsequent use effect.

The correct use of water-based color paste dispersants is crucial, from careful preparation in the early stage, to standardized addition steps, and then to strict attention to the key points in use. Only in this way can the role of water-based color paste dispersants be fully utilized to obtain high-quality, uniform and stable color water-based color paste products to meet the color needs of different industries.