Applications and Formulation Examples of Water-Based Polyurethane Adhesives

① Manufacturing of various laminated products, including plywood, composite plastic films for food packaging, fabric laminates, and laminates of various thin-layer materials, such as soft PVC plastic films or plastic sheets laminated with other materials (e.g., wood, fabric, paper, leather, and metal).
② Used as adhesives for flock printing, artificial leather, glass fibre and other fibre bundles, and ink.
③ Bonding of general-purpose materials, such as automotive interior trim materials.

Formulation Examples of Water-Based Polyurethane Adhesives

Water-Resistant and Heat-Resistant Water-Based Polyurethane Adhesives

Preparation Process: Mix 5 parts of allyl alcohol–vinyl alcohol copolymer with 95 parts of water, then blend with a butadiene–styrene copolymer latex, and finally combine with MDI and dibutyl phthalate to produce a water-based adhesive that is water- and heat-resistant.

Polyurethane Emulsion Adhesives

Preparation Procedure: Add castor oil to a reactor equipped with a thermometer, a stirring device, and a gas outlet tube; introduce a slow stream of nitrogen (until the reaction is complete); and perform dehydration under reduced pressure at 80°C for 1 hour. Cool to room temperature, then sequentially add TDI, monoethylene glycol, a chain extender, dried tartaric acid, and a small amount of acetone. Heat to approximately 55°C and maintain this temperature for 3 hours; if the mixture becomes too viscous during the reaction, add an appropriate amount of acetone to reduce the viscosity. Cool to room temperature, then add a prepared triethylamine aqueous solution (1:100) dropwise while vigorously stirring and simultaneously adding a small amount of acetone; the solution will change from a pale yellow, transparent colour to a milky white. When the pH of the solution reaches 7–8, stop adding the triethylamine aqueous solution and continue vigorous stirring for about 10 minutes to obtain a uniformly dispersed white emulsion.

Self-Emulsifying Polyurethane Emulsion Adhesives

Preparation Process: In a three-neck flask equipped with a thermometer and a stirrer, first dehydrate the polyether at 100–110°C for 2 hours; cool to below 40°C, add TDI dropwise, and maintain the temperature at 80–85°C for 3 hours; then cool to below 40°C, add dihydroxymethylpropane, and maintain the temperature at 50–60°C for 2 hours; after the reaction is complete, cool the reaction product and add it to an alkaline solution under vigorous stirring; after adding a chain extender, continue stirring for 5 minutes, add water, and disperse at high speed to obtain a self-emulsifying polyurethane emulsion adhesive.

Acrylic-Modified Water-Based Polyurethane Emulsion Adhesives