In the field of water-based architectural coatings, water-in-sand multicolor coatings have emerged as a high-efficiency solution that replaces the composite process of “real stone paint texture layer + multicolor coating.” This system can achieve a unique finish of high simulation and three-dimensional texture with just a single spray, successfully integrating the rich colors of multicolor coatings with the rustic texture of real stone paint. It offers significant advantages in improving application efficiency and reducing overall costs.
However, the core technical challenge lies in the stability of the system. The introduction of high-density quartz sand into the dispersed phase creates a tendency for phase separation: the sand and color dots are prone to settling and agglomeration due to density differences. Simultaneously, the larger particle size of the sand can puncture the gel film formed by the protective colloid on the surface of the color dots, leading to film structure defects. This results in color paste migration (commonly known as “color bleeding”) and reduced water-whitening resistance of the film, directly affecting the final decorative effect and project durability.
Key Technical Challenges and Solutions
Addressing these challenges requires optimizing the formula to focus on building a stronger three-dimensional network structure to encapsulate and stabilize the dispersed phase. Through systematic parallel experiments, Kaimaoxing (Kemox & Mixeon) has verified the critical role of Hydroxyethyl Cellulose (HEC) in this system. As a non-ionic water-soluble polymer, the long-chain molecules of HEC can form a high-viscosity three-dimensional network structure in the aqueous phase, providing excellent thickening, suspension, and water retention capabilities.
Experiments have shown that the introduction of HEC effectively:
- Enhances system suspension stability: Significantly slows the settling rate of sand and color dots, preventing the formation of hard sedimentation.
- Increases the toughness of the protective colloid film: Assists protective colloids (e.g., GS type) in forming a denser and more flexible continuous film, reducing film defects caused by sand particle puncture, thereby greatly improving color bleed resistance.
- Optimizes water-whitening resistance: Its excellent water retention property slows the migration of water into the film after application, allowing sufficient fusion time for emulsion particles, thus enhancing film density and resistance to whitening.
Recommended Formula and Process Highlights by Kaimaoxing (Kemox & Mixeon)
Based on experimental results, we recommend the following optimized core preparation process:
- Pigment Grinding and Dispersion Stage:
- Paint Mixing and Stabilization Stage:
- Key Parameters:
Conclusion
By precisely selecting and optimizing the ratios of key raw materials such as HEC, the inherent challenges of water-in-sand multicolor coatings—including storage stability, color bleed resistance, and water-whitening resistance—can be systematically resolved. The formula solution provided by Kaimaoxing offers a reliable technical pathway for developing next-generation textured exterior wall coatings that are high-performance, cost-effective, and easy to apply.
For more in-depth technical discussion regarding specific formulations or performance requirements, our application engineering team is available to provide further support.
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