Electrostatic flocking – Surface Modification

The technology of Surface Improvement. By changing surface characteristics of metal or plastic materials, new functionality or characteristics can be attributed to the base material. Surface Improvement technology is employed in many varied products that are commonly used on a daily basis all around you.

In this article we will discuss the technology of Electrostatic Flocking.

What is the frock finish (electrostatic flocking) process?

One of processing technologies in which short-length fibers, called “pile”, are evenly distributed and fixed on a pre-adhesive base material via very high voltage static electricity.

Human hair density is generally several hundreds/cm2 on average. On the other hand, flock finish technology enables a density of several thousands/cm2 fibers on average because each pile is able to stand vertically due to static electricity orienting the fibers.

There are two types of flock finished products: 1) Sheet Flock Product that processes on a flat sheet base, and 2) Form Flock Product that processes on a three-dimensional object. The Sheet Flock Product may have some pattern on its surface depending on its use. Form Flock Product have two different methods for achieving their configuration; one is to directly apply flock finish on a subject, and the other is to punch the Sheet Flock Products into several shapes necessary to form the final product and attach them with adhesive.

What is the material of the piles?

Primarly nylon and rayon, however, chemical synthetic fiber such as acrylic/polyester, natural fiber like silk or cotton, and functional fiber e.g. heat resistant fiber, can be used for piles.

What is the material of the adhesive?

Acrylic, urethane system, vinyl acetate ( wood adhesive) are the adhesive materials most commonly used. In the basic formula, these materials are not used alone. An epoxy like material is often added as cross-linking agent in order to improve membrane strength.

What is the base material ?

In case of the Sheet Flock finishing, base material can be vary; textile or knitted fabric of rayon and nylon, PET sheet film and vinyl chloride, formable materials such as urethane and polyethylene, non-woven fabric, paper, etc.

In case of the Form Flock finishing, base materials are plastic products (ABS PP,) or metal products (steel, SUS, aluminum).

What is the process for applying Flock Finishing ?

1) Coating of adhesive → 2) Flocking piles

→ 3) Dry and harden → 4) Hair removal and finishing

What are the properties of Flock Finished material ?

Low friction, vibration-free, adiathermacy, absorbent (light and water), water holding property, trap efficiency and retention.

What are some actual uses of Flock Finished products ?

■Automotive window seals

        → vibration control and low friction, smooth movement (up and
              down) of car windows.

■Hot Surface Protection

        → adiathermacy, prevention from finger or hand burned

■Cleaning rollers of spinning and weaving machinery

          → trap efficiency and retention, trap and retain waste thread 

■Cosmetic application

        → utilized as a “Powder Puff”, retention and super fine fiber are gentle on the skin.