Anti-blooming Dispersant Usage Guide: Unlocking the Secret of Uniform Color

Anti-blooming Dispersant Usage Guide: Unlocking the Secret of Uniform Color 

In the industrial production of coatings, inks and plastic coloring, blooming is a common problem that affects the appearance and quality of products. The uneven distribution of pigments leads to color spots, streaks or color differences, which not only reduces the aesthetics of the product, but also may affect its physical properties. As a key player in solving this problem, anti-flowering dispersants can effectively improve color uniformity and product stability by optimizing pigment dispersion. So, how to use anti-flake dispersant scientifically? This article will sort out the core points for you, and help you easily master the art of color management.

clear application scenarios, matching the type of dispersant 

There are many types of anti-flowering dispersants, which need to be accurately selected according to the system characteristics:

Water-based system: Priority is given to the use of hydrophilic groups containing carboxylates, polyethers and other dispersants to ensure compatibility with water-based resins, to avoid precipitation of the dispersant resulting in floating color or whitening.

Solvent-based system: Choose dispersants that match the polarity of the solvent (e.g., containing long-chain alkyl or aromatic groups) to prevent particles from agglomerating due to insufficient solubility of the dispersant.

Solvent-free/high-solids systems: High-temperature and shear-resistant dispersants are required to ensure that the dispersion effect is maintained during curing or high-temperature processing.

Special requirements: for coatings with high transparency, dispersants with strong binding power between anchoring groups and pigments and high spatial site resistance can be used to reduce the scattering of particles to light.

Precise control of additive amount to avoid “too much or too little” 

The amount of dispersant should be optimized through experiments, and excessive or insufficient amount may cause problems:

Insufficient dosage: the pigment is not completely dispersed, resulting in blooming, floating color or precipitation.

Excessive use: it may cause the viscosity of the system to increase, gloss to decrease, and even affect the adhesion or drying speed.

Suggestion: Determine the best dosage through gradient experiment, for example, gradually increase from 0.5% to 3% (based on the quality of pigment), and observe the balance point between dispersion effect and system performance.

Optimize the adding process to improve the dispersing efficiency 

The timing and process of adding dispersant directly affect its effect:

Add in pre-dispersion stage: add dispersant when the pigment is initially wetted, use mechanical stirring or sand mill to make the dispersant fully wrap the pigment particles and form a stable dispersion layer.

Step by step addition: for hard-to-dispersed pigments (such as organic red, carbon black), part of the dispersant can be added first for pretreatment, and then make up the remaining amount for further refinement.

Control process parameters: Dispersing temperature, time and shear force should match the characteristics of dispersant. For example, high temperature may accelerate the decomposition of dispersant, while insufficient shear force can not destroy the pigment agglomerates.

pay attention to system compatibility, avoid adverse reactions 

Dispersants need to work with other components in the system to avoid the following problems:

Conflict with resin: some dispersants may affect the film-forming or cross-linking reaction of resin, which should be verified by compatibility test.

Interaction with additives: For example, defoamers and leveling agents may compete with dispersants for adsorption sites, so the order of addition needs to be adjusted or better compatibility formulations need to be selected.

pH-sensitive dispersant: In aqueous system, pH fluctuation may affect the charge state of dispersant, which needs to be stabilized by buffer.

Strengthen process monitoring to ensure stable quality 

Key indicators need to be continuously monitored during the production process:

Evaluation of dispersing effect: detect the distribution of pigment particle size through particle size analyzer, ensure that D50 (median particle size) and D90 (90% of the particles passing through the particle size) are in line with the standard.

System Stability Test: Static observation of whether delamination or precipitation, or verification of long-term stability by accelerated aging test (e.g. high temperature and high humidity).

Color consistency verification: use a colorimeter to compare the Lab* values of different batches of products to ensure that the color difference ΔE ≤ 1 (imperceptible to the human eye).

safety and environmental protection and standardize the operation process 

Attention is required when using anti-flowering dispersant:

Protective measures: wear gloves, goggles and dust mask to avoid skin contact or inhalation of dust.

Storage conditions: sealed and protected from light, away from ignition sources and oxidizers, some dispersants may caking or decomposition in contact with water.

Waste disposal: Dispose of the remaining dispersant or cleaning wastewater according to local regulations to avoid environmental pollution.

Flexible response to challenges and continuous improvement of formulations 

In the face of complex systems or new types of pigments, it is necessary to combine experiments and experience to adjust the strategy:

Dispersant compounding: Combine different types of dispersants, such as ionic and non-ionic, to take into account both wetting and spatial resistance effects.

Introduction of synergistic additives: for example, wetting agent can reduce the surface tension of the pigment and help the dispersant adsorb faster; thickening agent can adjust the rheological properties of the system and reduce the settling of the pigment.

Case reference: a water-based wood paint enterprises through the compounding of two dispersants, carbon black particle size from 5μm down to 0.3μm, completely solved the problem of blooming, while the gloss increased by 15%.