Common LSE substrates include:

• Polyethylene (PE) and polypropylene (PP)
• Polyolefin foams
• EPDM and other synthetic rubbers
• Advanced automotive coatings and plastics

The fundamental challenge lies in surface energy mismatch. Conventional acrylic PSAs typically possess surface energies ≥35 dynes/cm, which limits their ability to adequately wet and adhere to lower-energy surfaces. Without sufficient wetting, bond formation is incomplete, resulting in poor adhesion performance.

Limitations of Conventional Approaches

Traditional approaches to improving LSE adhesion involve the incorporation of tackifying resins. While tackification can enhance initial wet-out and peel adhesion, it often introduces tradeoffs, including:

• Slip-stick or "zip" behavior during peel
• Reduced cohesive strength
• Diminished shear performance at elevated temperatures

Alternatively, rubber-based PSAs — particularly those based on SEBS elastomers — offer inherently lower surface energy and improved adhesion to LSE substrates. However, these systems typically sacrifice high-temperature performance and long-term durability, particularly in demanding environments such as automotive or marine applications.

A Hybrid Solution

ADHERON™ PS-100 introduces a hybrid approach that bridges the performance gap between acrylic- and rubber-based systems. It is a hybrid acrylic–rubber macromer designed for compatibility with:

• Solvent-based acrylic PSA formulations
• Commercial hydrocarbon tackifying resins

When incorporated into a PSA formulation, the additive enables the creation of a phase-optimized morphology in which:

• The acrylic phase maintains structural integrity and high-temperature shear strength
• The rubber component preferentially migrates and interacts at the adhesive-substrate interface, enhancing wetting and adhesion to LSE surfaces

This dual-phase behavior allows formulators to achieve improved interfacial adhesion without compromising cohesive performance.

Performance Benefits

Formulations incorporating the new additive demonstrate several key advantages:

• Enhanced adhesion to LSE substrates, including polypropylene and polyethylene
• Elimination of slip-stick behavior, resulting in smoother peel characteristics
• Retention of high-temperature shear strength, matching or exceeding base acrylic PSA systems
• Broad formulation compatibility, enabling straightforward incorporation into existing solvent-based PSAs

Importantly, the new product can be readily added to commercial solvent-based PSA systems, making it a practical solution for formulators seeking performance improvements without extensive reformulation.

Expanding the Capabilities of Acrylic PSAs

By overcoming the traditional tradeoff between adhesion to LSE substrates and cohesive strength, the additive expands the application window for acrylic PSAs. This enables their use in more demanding environments where both strong bonding to difficult surfaces and durability under heat and stress are required.

Conclusion

ADHERON PS-100 enhances the adhesion of solvent-based acrylic PSAs to low-surface-energy substrates while maintaining the elevated temperature shear properties required for demanding applications.

With this innovation, Estron Chemical continues to extend its expertise in polymer design into the adhesives market, providing formulators with a powerful new tool to meet evolving performance requirements across industries.

Estron Chemical is a global supplier of high-performance resins and additives for the coatings and adhesives industries. Learn more about the company at www.estron.com.

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