Anjeka 4420 Improving Storage Stability of 25% Pearlescent Pigment Formulations

In the pursuit of product differentiation, pearlescent effects are increasingly used in waterborne coatings and inks due to their unique visual appeal. However, pearlescent pigments, with their high specific gravity and platelet structure (e.g., at a loading of 25%), are prone to settling and caking during storage, leading to pain points like poor “in-can appearance,” application color difference, and uneven effects. This not only affects product quality but also directly tests the long-term stability of the formulation. How to maintain system homogeneity and stability under high loadings has become a key challenge for formulation engineers.

I. The Stability Challenge of High-load Pearlescent Pigment Systems
The essence of pearlescent pigments is mica platelets coated with metal oxides. Their platelet structure and relatively high density make them more susceptible to settling in waterborne systems. When the loading increases to 25% or higher, inter-particle interactions intensify, and dispersants alone are often insufficient for long-term stability. Common phenomena include:

• Hard Settling: Formation of dense, hard cake at the bottom after storage, difficult to redisperse by stirring.
• Effect Stratification: Clear supernatant, thin middle layer, and thick bottom layer, resulting in inconsistent effects with each sampling.
• Application Risks: Settlement leads to uneven orientation and distribution of pearlescent pigments during spraying or rolling, affecting the final sparkle and color consistency.

II. The Key to Anti-Settling: Building a Scientific “3D Support Network”
The core of solving settlement lies in constructing an appropriate three-dimensional network structure. This network needs to provide sufficient “supporting force” at rest (during storage) to hold pigment particles and prevent sinking; while under dynamic conditions (during application), it can be easily broken down, granting the system suitable fluidity. This requires the rheology modifier to possess good thixotropy: high viscosity at low shear rates (e.g., at rest) and rapidly decreasing viscosity at high shear rates (e.g., stirring, spraying).

III. 4420: Tailored for High-Solids Effect Pigment Systems
Addressing the anti-settling needs of high-load pearlescent and metallic pigments in waterborne systems, Angus Chem 4420 forms a uniform and appropriately strong three-dimensional hydrogen-bonding network through its unique chemical structure.

• Long-lasting Anti-settling, Easy Stir-in: Its network structure effectively suspends pearlescent pigment particles, preventing hard settling. After prolonged storage, only mild stirring is needed to restore a homogeneous state, ensuring consistent effects from the first can to the last.
• Excellent Application Adaptability: Under shear (e.g., stirring, pumping, spraying), the network is temporarily broken down, reducing system viscosity and ensuring good leveling and smooth application. Once shear stops, the network quickly rebuilds, preventing sagging during application, especially on vertical surfaces.
• Good System Compatibility: Optimized for waterborne systems, it exhibits good compatibility with various resins and additives. It has minimal impact on film gloss and transparency, ensuring a pure and vibrant pearlescent effect.

IV. Application Recommendations & Considerations
When developing high-load pearlescent effect systems, 4420 is recommended as a key candidate for the anti-settling solution.

1. Addition Stage: It is advised to add 4420 during the initial grinding/mixing stage with sufficient dispersive shear to ensure uniform distribution and effective network formation.
2. Dosage Exploration: For high-load systems like 25% pearlescent pigment, a starting dosage range of 0.8%-1.2% is recommended for gradient testing to find the optimal balance between storage stability and application leveling.
3. Synergistic Effects: It can be used in combination with Angus Chem's wetting and dispersing agents. First address primary dispersion and wetting of the pigment, then let 4420 provide long-term steric hindrance and rheological stability, achieving a “1+1>2” effect.

Don't let settling dim your brilliant pearlescent effects. If you are struggling with settling and caking issues of high-load effect pigments, or wish to enhance the storage stability of your existing system, the Angus Chem technical team can provide targeted solutions and sample support.

Take Action Now:

• Request a Free Sample: Verify the anti-settling performance of 4420 in your system.
• Obtain Technical Data: Gain an in-depth understanding of 4420's product characteristics and application guidelines.
• Technical Consultation: Contact our application engineers for an analysis of your system's pain points.