Unlock the correct use of color paste dispersants and start an efficient color journey
Unlock the correct use of color paste dispersants and start an efficient color journey
In the world of color, color paste dispersants are indispensable "behind-the-scenes heroes". They can evenly disperse pigment particles and give products bright and lasting colors. However, to give full play to the role of color paste dispersants, correct use is essential. The following is a detailed introduction to the use of color paste dispersants.
Accurate selection, adapt to needs
Select according to the color paste system
Color paste systems are mainly divided into water-based, oil-based and solvent-based, and different types of color paste systems have significantly different requirements for dispersants. The water-based color paste system uses water as a solvent and has good environmental protection, but the surface tension of water is large and the wettability of pigments is poor. At this time, a dispersant with good hydrophilicity and wettability should be selected, such as a polycarboxylate dispersant, which can quickly reduce the surface tension of water, fully wet the pigment particles and evenly disperse them.
Oil-based color paste systems often use organic solvents, and dispersants need to have good lipophilicity. For example, the lipophilic segments in the molecular structure of polymer block copolymer dispersants can be tightly combined with organic solvents, while the pigment-philic segments are adsorbed on the surface of the pigment, effectively preventing the aggregation of pigment particles. The solvent-based color paste system has high requirements for the solubility and stability of the dispersant, and it is necessary to select a dispersant compatible with it according to the specific solvent.
Selection based on the characteristics of the pigment
The type, particle size and surface properties of the pigment are different, and the selection of the dispersant should also be "tailored". For inorganic pigments, such as titanium dioxide and red iron oxide, their surface polarity is strong, and it is advisable to use dispersants with polar groups, such as phosphate dispersants, which can be firmly adsorbed on the surface of the pigment through electrostatic action and provide good dispersion stability.
Organic pigments have complex molecular structures and diverse surface properties. Some hydrophobic organic pigments require dispersants with strong lipophilicity, such as fatty amine dispersants, which can form a hydrophobic film on the surface of the pigment to prevent the pigment particles from agglomerating due to hydrophilicity. In addition, the particle size of the pigment will also affect the selection of dispersants. Fine-particle pigments have a large specific surface area and require more dispersants to cover their surface. Dispersants with strong adsorption capacity and high dispersion efficiency should be selected.
Reasonable dosage, just right
Follow the recommended dosage range
Each color paste dispersant has its recommended dosage range, which is the best dosage obtained after a lot of experiments and practice. If the dosage is too small, the dispersant cannot fully cover the surface of the pigment particles and cannot effectively prevent the aggregation of particles, resulting in uneven dispersion of the color paste, precipitation, stratification and other phenomena, affecting the color and quality of the product.
Excessive dosage will not only increase production costs, but also may have side effects. Too much dispersant may form micelles in the color paste, resulting in increased viscosity of the color paste and poor fluidity, which will bring difficulties to subsequent processing and application. Therefore, when using color paste dispersants, be sure to add them strictly in accordance with the recommended dosage range provided by the product manual or supplier.
Adjust according to actual conditions
In actual production, the amount of dispersant needs to be appropriately adjusted according to specific conditions. When the pigment content is high, the interaction between pigment particles is enhanced, and the amount of dispersant needs to be increased to ensure that the pigment is fully dispersed. For example, when producing high-concentration color paste, the amount of dispersant can be appropriately increased to the upper limit of the recommended amount.
The temperature and humidity of the production environment will also affect the effect of the dispersant. In a high temperature environment, the activity of the dispersant may be enhanced, and the amount can be appropriately reduced at this time; while in a low temperature environment, the dispersing efficiency of the dispersant may be reduced, and the amount needs to be appropriately increased. In addition, different production processes and equipment have different requirements for the dispersion of color pastes, and the amount of dispersant should be flexibly adjusted according to actual conditions.
Standardize operation to ensure the effect
Pre-dispersion treatment is essential
Before using the color paste dispersant, pre-dispersion treatment of the pigment is a key step to improve the dispersion effect. Pre-dispersion can make the pigment particles initially dispersed, reduce the agglomeration between particles, and create favorable conditions for subsequent dispersant adsorption and further dispersion.
Common pre-dispersion methods are dry grinding and wet grinding. Dry grinding is to mix the pigment and a small amount of dispersant, and then grind them in a grinding equipment to initially break and disperse the pigment particles. Wet grinding is to mix the pigment, dispersant and part of the solvent into a slurry, and then grind it in a grinder. This method has a better dispersion effect, but it is necessary to control the viscosity of the slurry and the grinding parameters.
The order of addition is particular
The order of adding the color paste dispersant also has an important influence on the dispersion effect. Generally speaking, the dispersant and part of the solvent should be mixed evenly to make a dispersant solution, and then the pigment should be gradually added to the dispersant solution. This allows the dispersant to fully wet the pigment particles and improve the dispersion efficiency.
If the pigment and solvent are mixed first and then the dispersant is added, the dispersant may not be adsorbed on the surface of the pigment particles in time, and some pigment particles have already agglomerated, affecting the final dispersion effect. During the addition process, the pigment should be added slowly and stirred continuously to fully mix the pigment and dispersant solution.
Full stirring and grinding
Stirring and grinding are important means to make the color paste dispersed evenly. After adding the pigment and dispersant, stir fully so that the pigment particles and the dispersant are fully contacted and adsorbed. The stirring speed and time should be adjusted according to the viscosity and dispersion requirements of the color paste. Generally speaking, the stirring speed should not be too fast to avoid excessive bubbles and affect the quality of the color paste.
For some color pastes with high dispersion requirements, grinding is also required. Grinding can further refine the pigment particles and improve the uniformity and stability of dispersion. When selecting grinding equipment, it is necessary to make reasonable choices based on the properties of the color paste and the production scale, such as sand mills, ball mills, etc. During the grinding process, it is necessary to control parameters such as grinding time, pressure and temperature to avoid excessive grinding and causing pigment performance degradation.
Proper storage to ensure quality
The storage environment should be suitable
Color paste dispersants have certain requirements for the storage environment. They should be stored in a cool, dry and well-ventilated place, avoiding direct sunlight and high temperature environment. High temperature may cause the dispersant to decompose and deteriorate, affecting its dispersion performance. At the same time, stay away from fire sources and flammable materials to prevent safety accidents such as fire.
Humidity will also affect the dispersant. Excessive humidity may cause the dispersant to absorb moisture and agglomerate, reducing its use effect. Therefore, the relative humidity of the storage place should be controlled within a certain range, generally not exceeding 70%.
Sealed storage to prevent deterioration
Color paste dispersants should be sealed during storage to prevent moisture, oxygen and other impurities in the air from entering. They can be stored in well-sealed containers, and the product name, specifications, production date and shelf life should be marked on the containers for easy management and use.
Regularly check the stored dispersants. If abnormal conditions such as agglomeration, discoloration, and odor are found, they should be handled in time to avoid using deteriorated dispersants to affect product quality.
The correct use of color paste dispersants is crucial to ensure the quality and performance of color pastes. Through precise selection, reasonable dosage, standardized operation and proper storage, we can give full play to the role of color paste dispersants, give products bright, lasting and stable colors, and create more excitement in the world of color.