Bonding Mechanism
Polyvinyl acetate emulsions rely on the evaporation of water to attain a solid state without the application of heat to the interface. Cold set adhesive polymers gain mechanical strength through the absorption of moisture into porous substrates like paper or board. This rapid water migration triggers a phase change that locks the fibres into a rigid matrix.
Ambient temperatures allow these formulations to reach a stable state within the constraints of high speed converting lines.
Application Parameters
The viscosity of the fluid requires consistent control to maintain accurate laydown patterns on automated gluing heads. When using cold set adhesive solutions the nozzle pressure must match the absorption rate of the stock to prevent bleed through or bond failure. Excessive application quantities saturate the fibres and cause warping or cockling in thin grammage papers.
Proper roller adjustment or orifice selection determines the width of the bead and the subsequent integrity of the carton seal.
Chemical Stability
Synthetic resin dispersions provide resistance to humidity and minor temperature fluctuations once the film dries completely. Manufacturers formulate cold set adhesive compounds with specific solid content levels to optimize the open time before the joint reaches full setting velocity. These formulations remain stable in storage tanks provided the air exposure stays minimal to prevent premature skinning or crusting at the surface.
High shear pump systems effectively move the material throughout the delivery circuit without breaking the polymer chains. Cold set adhesive integrity remains constant across a wide variety of machine speeds provided the substrate porosity permits consistent penetration.
