What are the dispersants? Selection of wetting and dispersing agents

In order for the dispersant to produce effective dispersion, the dispersant must be in the pigment Firm adsorption is crucial, and this process is related to the structural composition of the pigment. Inorganic pigments have an ionic structure and high polarity, so the adsorption of dispersants is relatively easy. Organic pigments (including carbon black) are crystals composed of non-polar molecules with low polarity. It is quite difficult for low molecular weight dispersants to adsorb on the surface of such pigments. As a result, this type of dispersant has a negative impact on organic pigments and The deflocculation and stabilization effects of carbon black are insufficient. This problem was not solved until the emergence of high molecular weight polymer-based wetting and dispersing agents.

Characteristics of ink wetting and dispersing agents And its function is to use wetting and dispersing agents to reduce the time and energy required to complete the dispersion process, stabilize the pigment dispersion that needs to be dispersed, and adjust the mobility of the pigment particles by grinding and dispersing the surface properties of the pigment particles.

So far, improving the dispersion and dispersion stability of pigments in aqueous systems There are many methods, such as rosin treatment method, pigment derivative method, organic amine treatment method, adding dispersant method, plasma treatment method, ultrafine particle adsorption method, microcapsule method, etc. Among them, the method of adding dispersant is the most widely used method with good dispersion effect. Adding dispersants during the pigment dispersion process is the most effective way to maintain stable pigment dispersion. Some dispersants also have a wetting effect and are called wetting and dispersing agents. Pigment dispersants mainly maintain the stability of pigment dispersions through the following two functions:

Dispersants can control the particle size of pigments and fillers within a small range, preventing pigments and fillers from The particles are agglomerated again. The wetting agent improves the wettability of highly hydrophobic organic pigments by reducing the surface tension of the system and enhances the coating performance of the paint. Used with dispersants, inorganic and organic pigments can be dispersed evenly to produce paints with good color tones.