Acrylic Emulsion Used in Fiberglass Mesh Coating

1. Introduction

Fiberglass mesh is a critical reinforcement material widely used in construction systems such as external thermal insulation and finishing systems (EIFS), waterproofing membranes, gypsum boards, cementitious renders, and crack-resistant wall coatings. To ensure durability, alkali resistance, flexibility, and handling performance, fiberglass mesh must be treated with a high-performance coating. Among various polymer systems, acrylic emulsion has become one of the most commonly used coating binders for fiberglass mesh due to its excellent balance of mechanical performance, chemical resistance, processability, and environmental compliance.

Acrylic emulsion–based coatings protect fiberglass yarns, improve mesh integrity, and enhance compatibility with cementitious and polymer-modified mortars. As construction standards become more demanding and sustainability requirements increase, acrylic emulsions continue to play a central role in modern fiberglass mesh coating technology.

2. Fiberglass Mesh and the Need for Coating

Fiberglass mesh is produced from glass fiber yarns woven into an open grid structure. While glass fibers possess high tensile strength and dimensional stability, they are inherently brittle and susceptible to alkaline attack, especially in cement-based environments.

Uncoated fiberglass mesh faces several challenges:

• Poor resistance to alkaline cement mortars

• Fiber breakage during handling and installation

• Dusting and filament separation

• Reduced long-term reinforcement performance

A polymer coating is therefore essential. Acrylic emulsion coatings encapsulate the glass fibers, bind intersecting yarns, and form a protective barrier that significantly improves durability and service life.

3. Acrylic Emulsion: Composition and Key Properties

Acrylic emulsions are water-based dispersions of acrylic or methacrylic copolymers produced via emulsion polymerization. Typical monomers include butyl acrylate, ethyl acrylate, methyl methacrylate, and functional monomers to enhance adhesion or crosslinking.

Key properties of acrylic emulsions relevant to fiberglass mesh coating include:

• Excellent film-forming ability at moderate drying temperatures

• Strong adhesion to inorganic glass fiber surfaces

• Flexibility and elasticity, preventing cracking under stress

• Good alkali resistance, essential for cement-based applications

• UV and weather resistance, suitable for exterior construction use

The ability to tailor glass transition temperature (Tg) allows formulators to design coatings that balance softness for flexibility with hardness for mechanical strength.

4. Role of Acrylic Emulsion in Fiberglass Mesh Coating

In fiberglass mesh applications, acrylic emulsion serves as the primary binder in the coating formulation. After application and drying, the emulsion forms a continuous polymer film that performs several critical functions:

Fiber Protection

The acrylic coating acts as a barrier between the glass fibers and alkaline cementitious materials, significantly slowing chemical degradation and extending service life.

Structural Integrity

By bonding warp and weft yarns at their intersections, the acrylic film stabilizes the mesh structure, improving dimensional stability and tensile performance.

Flexibility and Handling

Acrylic-coated mesh remains flexible and easy to roll, cut, and install, reducing breakage and dust generation during construction.

Compatibility with Mortars

Acrylic emulsions exhibit good compatibility with cement, gypsum, and polymer-modified mortars, ensuring effective stress transfer between reinforcement mesh and base coat.

5. Coating Formulation and Additives

A typical fiberglass mesh coating formulation based on acrylic emulsion may include:

• Acrylic emulsion binder

• Fillers or pigments (optional, for color or cost control)

• Wetting and dispersing agents

• Anti-foaming agents

• Thickeners for viscosity control

• Crosslinking agents (in some systems)

The solids content and viscosity are carefully adjusted to ensure proper penetration into the fiberglass yarn bundles while maintaining sufficient surface coverage.

Self-crosslinking or post-crosslinking acrylic emulsions are sometimes used to enhance water resistance and mechanical strength without sacrificing flexibility.

6. Application Process

The fiberglass mesh coating process typically involves the following steps:

1. Impregnation or dip-coating of the woven fiberglass mesh into the acrylic emulsion bath

2. Controlled squeezing or metering to remove excess coating and regulate add-on weight

3. Drying and curing at elevated temperatures to remove water and form a continuous polymer film

Acrylic emulsions are well suited for high-speed, continuous coating lines due to their stability and consistent rheological behavior. The resulting coated mesh exhibits uniform coating weight and reliable performance.

7. Performance Advantages in Construction Applications

Alkali Resistance

One of the most important performance requirements for fiberglass mesh is resistance to alkaline environments. Acrylic emulsion coatings significantly enhance alkali durability, enabling long-term reinforcement performance in cement-based systems.

Mechanical Strength

The coating improves tensile strength retention and tear resistance, helping the mesh absorb and distribute stresses caused by thermal movement, shrinkage, or mechanical impact.

Weatherability

Acrylic polymers offer excellent resistance to UV radiation, moisture, and temperature fluctuations, making them ideal for exterior insulation systems and façade applications.

Crack Resistance

When embedded in base coats or renders, acrylic-coated fiberglass mesh helps prevent surface cracking and improves overall system durability.

8. Environmental and Safety Considerations

Acrylic emulsions are water-based and contain low levels of volatile organic compounds (VOCs), making them safer to handle and more environmentally friendly than solvent-based coatings.

Modern acrylic emulsions used for fiberglass mesh are often:

• APEO-free

• Formaldehyde-free

• Compliant with global construction and environmental regulations

These attributes support green building initiatives and sustainable construction practices.

9. Typical Applications of Acrylic-Coated Fiberglass Mesh

Acrylic emulsion–coated fiberglass mesh is widely used in:

• External thermal insulation and finishing systems (EIFS/ETICS)

• Waterproofing membranes and roofing systems

• Cement and gypsum board reinforcement

• Interior and exterior wall crack-prevention systems

• Renovation and repair applications

The versatility of acrylic emulsions allows the same base technology to be adapted for different mesh weights, grid sizes, and performance requirements.

10. Future Development Trends

As construction materials continue to evolve, acrylic emulsion technology for fiberglass mesh coating is also advancing. Key trends include:

• Enhanced alkali-resistant formulations for longer service life

• Lower-energy curing systems to reduce manufacturing costs

• Improved adhesion to modified cement systems

• More sustainable acrylic polymers with reduced environmental impact

These developments will further strengthen the role of acrylic emulsions in high-performance reinforcement materials.

11. Conclusion

Acrylic emulsions are a vital component in fiberglass mesh coating technology. By providing protection, flexibility, durability, and compatibility with cementitious systems, they enable fiberglass mesh to perform reliably in demanding construction environments. With their proven performance, environmental advantages, and formulation versatility, acrylic emulsion–based coatings will remain a key solution for fiberglass mesh reinforcement in modern building systems.