Industrial Reactors for Adhesive Production: White Glue, Hot Melt, and More

Introduction

In the adhesive manufacturing industry, reactors play a crucial role in producing various types of glues, including white glue (PVA emulsion), hot melt adhesives (HMA), and other synthetic adhesives. These reactors ensure precise temperature control, efficient mixing, and chemical stability during production.

This blog post explores:

• The types of reactors used in adhesive manufacturing

• Key processes for making white glue, hot melt adhesives, and other glues

• Design considerations for adhesive reactors

• Industrial applications

Types of Reactors Used in Adhesive Production

1. Batch Reactors

• Most common in small to medium-scale adhesive production.

• Used for PVA emulsions (white glue), acrylic adhesives, and epoxy resins.

• Features:

  • Jacketed heating/cooling (steam or thermal oil)

  • High-shear mixing for uniform dispersion

  • Temperature and pressure control

2. Continuous Reactors

• Used in large-scale production of hot melt adhesives (HMA) and pressure-sensitive adhesives (PSA).

• Provides consistent output with automated feeding of raw materials.

• Types:

  • Tubular reactors (for polymerization reactions)

  • Extruder reactors (for melting and compounding HMAs)

3. High-Viscosity Reactors

• Designed for thick adhesives like polyurethane (PU) and silicone-based glues.

• Equipped with anchor or helical agitators for efficient mixing.

Key Adhesive Production Processes

1. White Glue (PVA Emulsion) Production

• Process:

  1. Mixing phase: Water, polyvinyl acetate (PVA), and plasticizers are loaded into the reactor.

  2. Emulsification: Stabilizers and surfactants are added under controlled temperature (60–80°C).

  3. Polymerization: Initiators (e.g., peroxides) trigger polymerization.

  4. Cooling & packaging: The emulsion is cooled, filtered, and packed.

• Reactor requirements:

  • Stainless steel construction (corrosion-resistant)

  • High-shear dispersers for uniform emulsion

2. Hot Melt Adhesive (HMA) Production

• Process:

  1. Melting phase: Thermoplastic polymers (EVA, SBS, polyolefins) are melted at 120–200°C.

  2. Mixing: Tackifiers (rosin, hydrocarbons) and waxes are blended in.

  3. Degassing: Volatiles are removed under vacuum.

  4. Extrusion & pelletizing: The molten adhesive is extruded into pellets or films.

• Reactor requirements:

  • High-temperature heating (electric or thermal oil)

  • Twin-screw extruders for compounding

3. Other Adhesives (Epoxy, PU, Cyanoacrylate)

• Epoxy resins: Require precise temperature control to prevent premature curing.

• Polyurethane (PU) adhesives: Need moisture-free conditions and vacuum reactors.

• Cyanoacrylate (super glue): Produced in small batch reactors due to fast polymerization.

Design Considerations for Adhesive Reactors

✔ Material Compatibility – Stainless steel (316L) for corrosive chemicals.
✔ Heating & Cooling Systems – Jacketed reactors with steam, thermal oil, or electric heating.
✔ Mixing Efficiency – High-shear agitators for emulsions; anchor mixers for viscous adhesives.
✔ Safety Features – Pressure relief valves, nitrogen blanketing (for oxidation-sensitive reactions).
✔ Automation & Control – PLC systems for precise temperature, pH, and viscosity monitoring.

Industrial Applications

• Woodworking & Packaging (PVA white glue)

• Automotive & Electronics (Hot melt adhesives)

• Construction & Footwear (Polyurethane adhesives)

• Medical & Consumer Goods (Cyanoacrylate-based adhesives)

Conclusion

Industrial reactors are essential for producing high-quality adhesives with consistent properties. Depending on the type of glue—whether white glue, hot melt, epoxy, or PU—the reactor design must ensure proper mixing, temperature control, and safety.

Modern adhesive manufacturing relies on automated, high-efficiency reactors to meet industry demands for performance and sustainability.