Comprehensive Paint Formulation using Acronal 790

An in-depth guide to creating a high-performance Acronal 790-based paint

Highlights

Binder Performance: Acronal 790 provides excellent pigment binding and long-lasting adhesion.
Additive Roles: Rheology modifiers, dispersants, and coalescing agents enhance viscosity, pigment dispersion, and film formation.
Application Versatility: The formulation can be tailored for interior and exterior use with superior water resistance and durability.

Introduction

Acronal 790, an aqueous dispersion of a styrene-acrylic copolymer, is widely acclaimed in the coatings industry for its excellent pigment binding properties, robust adhesion, and versatility in various paint types including interior, exterior, and textured finishes. This formulation guide is designed to offer a comprehensive, step-by-step approach to creating a superior paint formulation using Acronal 790. In this guide, we integrate best practices for component selection, mixing techniques, and performance testing to ensure that the final product meets desired aesthetic and functional characteristics.

Formulation Overview

Key Categories of Components

The formulation for a high-quality paint with Acronal 790 is divided into several key component categories. Each category plays a vital role in ensuring the paint’s performance. The components include:

Binder System: The core component responsible for film formation and adhesion.
Solvent/Vehicle: Generally water, which acts as the medium in which all components are dispersed.
Pigments & Fillers: Substances that provide color, opacity, and bulk. Titanium dioxide (TiO₂) is typically used for white formulations.
Additives: These include rheology modifiers, dispersing agents, foam control agents, biocides, and coalescing agents which collectively improve mixing, stability, and the overall performance of the paint film.
Thickeners: These are used to adjust ink consistency and control viscosity, ensuring proper flow and leveling during application.
pH Adjusters: Agents such as ammonia or sodium hydroxide that maintain the system at a proper pH level to optimize stability and performance.

Detailed Formulation Components

1. Binder System

The binder in this formulation is Acronal 790, known for its high binding capacity and excellent adhesion properties. It ensures that pigments are firmly anchored within the paint film, preventing degradation and loss of color over time.

Acronal 790: Utilized as the primary binder, it generally constitutes about 30-40% of the total formulation. Its unique properties allow it to perform well in a variety of environmental conditions, ensuring durability and resistance to water.

2. Solvent/Vehicle

Water serves as the primary solvent in this formulation. Using distilled or deionized water not only ensures purity but also minimizes potential impurities that can affect pigment dispersion or stability.

Water: Typically makes up 40-50% of the formulation, acting as the medium to disperse binder, pigments, and additives uniformly.

3. Pigments and Fillers

Pigments are crucial for imparting color and opacity whereas fillers like calcium carbonate (CaCO₃) add bulk and enhance the final texture. Titanium dioxide (TiO₂) is the most common pigment due to its excellent covering power and brightness.

Titanium Dioxide (TiO₂): Typically constitutes 10-15% of the formulation providing high opacity and a bright white finish. Additional color pigments can be added up to 5% based on specific requirements.
Fillers: Fillers such as calcium carbonate may be introduced at levels around 20% to balance cost and physical properties.

4. Additives

Rheology Modifiers

Rheology modifiers are employed to control the viscosity and flow behavior of the paint. They ensure that the paint can be applied smoothly and maintains a stable consistency during storage.

Natrosol™ 250 HHBR or Natrosol™ Plus 330: Typically used at concentrations of 1-2% to adjust the viscosity.

Dispersing Agents

Dispersing agents ensure that pigments are uniformly distributed throughout the paint without clumping, leading to a more consistent color and finish.

Sodium Polyacrylate: Commonly used at 0.5-1% to promote uniform dispersion of pigments.

Foam Control Agents

Foam formation during the mixing process can lead to defects in the finished film. Foam control agents help manage and minimize the formation of foam.

Mineral Oil (e.g., Drewplus™ L-1311E): Added in quantities of 0.1-0.5% to reduce foam and improve the overall quality of the finished product.

Biocides

Biocides, such as Nuosept BM11, are essential for protecting the formulation against microbial growth during both storage and application. They help ensure the longevity and sanitary integrity of the product.

Nuosept BM11: Used at low concentrations (0.1-0.5%) to prevent mold and bacterial contamination.

Coalescing Agents

Coalescing agents assist in film formation by promoting the merging of polymer particles during the drying process. This results in a smoother and more uniform paint film.

Coalescing Agents (e.g., Texanol®, Dowanol PM): Typically added at 3-5% to improve film uniformity and adhesion.

5. Thickeners

Thickeners such as cellulose ethers (e.g., hydroxyethyl cellulose) or synthetic polyacrylates help in achieving the desired consistency and prevent sagging during application. Their function is critical to maintaining the overall viscosity of the paint.

Cellulose Ethers or Synthetic Thickening Agents: Generally added as required to reach the target rheological properties.

6. pH Adjusters

Maintaining the correct pH is important for ensuring the stability of the dispersion and the longevity of the paint film. Adjusters such as ammonia or sodium hydroxide are used to fine-tune the pH typically in the range of 7.5 to 9.0.

Ammonia or Sodium Hydroxide: Applied as needed to reach appropriate pH levels for optimal performance.

Step-by-Step Formulation Procedure

I. Preparation of the Pigment Dispersion

Mixing the Pigment and Fillers

Begin by dispersing the pigments and fillers. In a high-speed mixer or a ball mill, blend Titanium Dioxide (TiO₂) with any additional color pigments and fillers like calcium carbonate in a portion of deionized water. Include a suitable dispersing agent to assist in breaking up agglomerates and ensure a uniformly dispersed mixture.

Wetting Agents and pH Control

Add a small quantity of a wetting agent, such as a nonionic surfactant, to the pigment dispersion. This aids in better pigment wettability and improves the ease of dispersion. Monitor the pH and adjust if necessary using mild pH adjusters.

II. Binder Dispersion Preparation

Mixing Bound Binder and Solvent

In another container, combine Acronal 790 with the remaining portion of deionized water. During this phase, slowly add coalescing agents (Texanol® or Dowanol PM) while stirring to encourage partial coalescence of the binder particles, which aids in better film formation once the paint dries.

III. Combining the Pigment and Binder Mixtures

Once both the pigment dispersion and the binder mixture have been prepared, gradually incorporate the pigment mixture into the binder under continuous stirring. This controlled blending ensures that the pigments are evenly incorporated into the binder, forming a homogeneous system. Constant stirring helps in avoiding any sedimentation or clumping that may disrupt the integrity of the final paint.

IV. Addition of Additives and Final Adjustments

After achieving a uniform pigmented binder system, add the remaining additives in sequence. First, introduce the rheology modifier (e.g., Natrosol™ Plus 330) to achieve the desired viscosity. Then, include the foam control agent (mineral oil) followed by the biocide (Nuosept BM11) to safeguard the stability of the formulation.

Adjust the formulation as needed with synthetic thickeners or additional water to reach the precise flow and leveling characteristics required for your application. The final pH should be checked and adjusted to between 7.5 and 9.0 to maintain stability throughout storage and drying.

Formulation Summary Table

The following table summarizes a typical paint formulation using Acronal 790. Adjust percentages as necessary to suit specific performance or application needs:

Component	Function	Typical % Range
Acronal 790	Binder / Film Former	30-40%
Deionized Water	Solvent / Medium	40-50%
Titanium Dioxide (TiO₂)	Opacity and Pigmentation	10-15%
Color Pigments (Optional)	Desired Coloration	Up to 5%
Calcium Carbonate (Fillers)	Bulk and Cost Efficiency	Variable (up to 20% if used)
Rheology Modifiers (Natrosol™)	Viscosity Control	1-2%
Dispersing Agents (Sodium Polyacrylate)	Uniform Pigment Dispersion	0.5-1%
Foam Control Agent (Mineral Oil)	Minimize Foaming	0.1-0.5%
Biocide (Nuosept BM11)	Prevent Microbial Growth	0.1-0.5%
Coalescing Agent (Texanol® / Dowanol PM)	Film Formation & Uniformity	3-5%
pH Adjusters (Ammonia or NaOH)	Stability	As needed

Quality Control and Testing

Performance Evaluation

After formulating the paint, it is critical to subject the product to a series of tests that evaluate performance parameters such as:

Viscosity and Flow

Conduct viscometry tests to measure the flow properties, ensuring that the formulation applies evenly and levels out smoothly.

Film Formation and Drying Time

Check the coalescence process as the film forms, verifying that the coalescing agents are effectively promoting a uniform, defect-free finish for both minimum and maximum film thicknesses.

Adhesion and Durability

Perform adhesion tests on various substrates. Evaluate the durability of the paint film under mechanical stresses and exposure to moisture.

Resistance to Moisture and Dirt Pick-Up

Ensure that the water resistance and dirt pick-up resistance meet or exceed expected performance standards for both interior and exterior applications.

Additional Considerations

When working with Acronal 790-based formulations, it is important to factor in environmental and safety considerations. Always follow proper safety protocols when handling chemical components and ensure that the manufacturing environment is well-ventilated. Additionally, variations in raw material quality can influence the final paint performance, so quality control at the supplier level is recommended.

Moreover, small adjustments may be necessary during scaling from laboratory formulations to industrial manufacturing. Pilot batches should be prepared and tested to fine-tune the formulation before full-scale production begins.

Conclusion

Creating a paint formulation with Acronal 790 involves a carefully balanced process where careful selection, proportioning, and blending of various components are paramount. From the critical role of the binder providing robust film formation and adhesion, to the use of additives such as rheology modifiers, dispersants, foam control agents, and coalescing agents, each ingredient is essential in producing a high-quality product. This comprehensive guide is intended to serve as a blueprint that can be adapted for different types of paint, whether for interior, exterior, or specialized textured finishes.

By adhering to the formulation guidelines provided above, formulators can ensure that their paint meets industry performance standards, maintaining consistent viscosity, optimal film formation, water resistance, and durability. It is important to conduct thorough quality control and performance testing at every stage of production to adjust the formulation for specific substrates and environmental conditions. Overall, this formulation represents a versatile and reliable approach for maximizing the potential of Acronal 790 in paint production.

References

Styrene Acrylic Interior Flat White Paint with Acronal 790 - Chemiteca
Acronal S 790 - BASF Product Finder
Acronal S 790 Details - Ataman Chemicals
Technical Information for Acronal S 790 - UTSRus