Teach you how to use it step by step! The correct steps and skills for using spray ink dispersants
Teach you how to use it step by step! The correct steps and skills for using spray ink dispersants
The use of spray ink dispersants needs to be combined with the ink formula, process and target effect. During its use, attention should be paid to the selection of dispersants, the timing of addition, the amount control and the operating specifications. The following are detailed methods of use and precautions:
1. Preparation before use
Choose a suitable dispersant
Choose according to the type of ink: solvent-based, water-based or UV inks need to match the corresponding dispersants. For example, water-based inks need to use hydrophilic dispersants, and UV inks need to adapt to the light-curing system.
Choose according to the characteristics of the pigment: Different pigments (such as organic pigments and inorganic pigments) have different requirements for dispersants. For example, organic pigments require dispersants with high dispersion efficiency, and inorganic pigments require dispersants with high stability.
Choose according to the substrate: For different substrates such as plastics, metals, and paper, dispersants need to improve the wettability and adhesion of the ink.
Determine the amount to be added
Reference to supplier recommendations: Dispersant suppliers usually provide recommended dosages (such as 1%-5% of the pigment mass).
Conduct a small test: Determine the optimal dosage through gradient experiments to avoid excessive dosage that may lead to decreased ink performance (such as abnormal viscosity and reduced gloss).
2. Usage
Pre-dispersion stage
Direct addition method: Add the dispersant directly to the pigment and mix it preliminarily by stirring or grinding.
Pre-dissolution method: For water-based inks, the dispersant can be dissolved in water first, and then the pigment can be added.
Grinding and dispersion stage
Equipment selection: Use equipment such as sand mills, ball mills or three-roll mills for high shear grinding.
Grinding time control: Adjust the grinding time according to the pigment fineness and dispersion effect to avoid excessive grinding that leads to too small pigment particle size.
Post-processing stage
Filtration: Remove impurities or large particles that may be generated during the grinding process.
Viscosity adjustment: Add thickeners or diluents as needed to adjust the ink viscosity.
3. Precautions
Compatibility of dispersants and ink systems
Solvent compatibility: Ensure that the dispersant is compatible with the solvents, resins and other components in the ink to avoid stratification or precipitation.
pH control: In water-based inks, dispersants are sensitive to pH and need to be controlled within an appropriate range (e.g., 7-9).
Operating environment and safety
Temperature control: Control the temperature during grinding to avoid high temperatures causing dispersant decomposition or changes in ink performance.
Protective measures: Wear protective equipment during operation to avoid contact with skin or inhalation of dust.
Dispersion effect evaluation
Particle size analysis: Use a laser particle size analyzer to detect the pigment particle size distribution to ensure that the target fineness is achieved (e.g., D50 < 1μm).
Stability test: Evaluate the dispersion stability of the ink through experiments such as centrifugation and heat storage.
Printing test: Verify the fluidity, adhesion, and gloss of the ink in actual printing.
4. Common problems and solutions
Pigment agglomeration
Cause: Insufficient dispersant or insufficient grinding time.
Solution: Increase the amount of dispersant or extend the grinding time.
Ink stratification
Cause: The dispersant is incompatible with the ink system or the storage conditions are improper.
Solution: Replace a dispersant with better compatibility or improve the storage environment (e.g., sealing, avoiding light).
Poor printing quality
Reason: Improper selection of dispersant leads to insufficient ink adhesion or glossiness.
Solution: Reselect a dispersant suitable for the substrate or adjust the ink formula.
5. Summary
The use of spray ink dispersants requires comprehensive consideration of ink type, pigment characteristics, substrate requirements and process conditions. By scientifically selecting dispersants, strictly controlling the addition amount and grinding process, and strengthening the evaluation of dispersion effects, the dispersibility, stability and printing performance of the ink can be significantly improved. In practical applications, it is recommended to combine small-scale experiments and supplier technical guidance to optimize the use of dispersants.