How is Flock Applied?

Flock fibres are usually applied to adhesive-coated surfaces mechanically, electrostatically or by a combination of both techniques.

Mechanical coating on flat surfaces is usually done by the beater-bar method. This technique involves the passage of an adhesive-coated substrate over a series of polygonal rollers that rapidly rotate to vibrate the substrate. The vibration is used to drive the fibre into the adhesive. Fibres are fed to the substrate by gravity from a flock module. Windblown mechanical flocking uses an airstream to deliver the fibres to an adhesive-coated surface. This method is well established for the coating of three-dimensional objects such as the inside of automobile glove boxes and latex gloves.

Electrostatic flocking is a modern technique, which utilises a field of static electricity to orient fibres and promote their perpendicular alignment. This technique optimises the results obtained with longer fibres. In this method of electrostatic deposition, the adhesive coated substrate passes between the potentials of a high voltage electrostatic field. An electrode is utilised to give the flock a charge. The charged fibres become aligned with the electric field lines of force. The ground potential is formed by the substrate anode or the grounded parts of the machine. The flock is thus attracted to the adhesive where it becomes embedded. Most fibres adhering to the adhesive-coated surface are perpendicular to it giving a dense pile finish. Since it is the nature of the field to align the fibres perpendicular to a surface, almost any shape object can be flocked.

Windblown and electrostatic methods can also be utilised simultaneously through pneumatic/electrostatic flocking. With this method an airstream containing the fibres is directed through a nozzle. At the exit of the nozzle, a charge orients the fibres according to the field lines. The pneumatic/electrostatic technique allows for even coverage of complex three-dimensional shapes. The beater-bar technique assures an excellent bond by seating the fibre deeply in the adhesive; electro-deposition achieves high fibre density and more vertical orientation. Combining both methods maximises bonding and fibre density.