Preparation and optimization of a lignin-based pressure-sensitive adhesive

Area of Science:

• Materials Science
• Polymer Chemistry
• Adhesives Technology

Background:

• Pressure-sensitive adhesives (PSAs) are crucial for applications like sticky notes.
• Developing sustainable and high-performance PSAs from renewable resources is an ongoing challenge.
• Lignin, a byproduct of the paper industry, presents an opportunity for creating bio-based adhesives.

Purpose of the Study:

• To optimize the formulation of lignin-based PSAs for sticky note applications.
• To investigate the influence of compositional and processing parameters on PSA performance.
• To develop a novel method for assessing PSA performance using peel-off losses.

Main Methods:

• D-optimal experimental design was employed in two steps to optimize PSA formulation.
• Organosolv lignin was incorporated into a polycarboxylate polyether (PCE)/water matrix.
• Key responses analyzed included ball tack, peel-off losses, and water content.

Main Results:

• The optimized formulation (DES-OL-OPT) contains 5 wt% lignin, 84 wt% PCE, and 11 wt% water.
• Optimal curing conditions were determined as 130°C for 60 minutes.
• The model demonstrated high accuracy, with coefficients of determination of 0.98 for tack, 0.99 for peel-off losses, and 0.99 for water content.
• The resulting lignin-based PSA exhibited higher tackiness and similar peel-off losses compared to commercial products.

Conclusions:

• Lignin-based PSAs can be effectively prepared for sticky note applications.
• The D-optimal design methodology provides a robust approach for optimizing adhesive formulations.
• The developed peel-off loss method offers a reliable way to evaluate PSA performance.