Metallic Fibre By Mahmood Azeem

Seminar Fib-Tech-720

Metallic Fibre Mahmood Azeem 2006-ag-148

Metallic Fibre Introduction: ► Metallic fibre is usually made from the strip of aluminium foil which is sandwiched between the two layers of polyester film. In another method, the strip of synthetic film, such as polyester is coated with metallic particles. Metallic fibres are usually washable, and do not loose lustre due to the exposure of air or temperature. They are resistant to attack by insects and micro-organisms. They are used for antistatic fabrics, fire worker suits and for cut resistant gloves, etc.

Production methods There are two basic processes: ► Laminating

process

► Metallizing

process.

Laminating Process ► The

raw material is a roll of aluminium foil of 0.011 mm thickness and 20 inch wide. The both sides of the sheet are applied a thermoplastic adhesive. The foil is heated upto 90-95°C, and a sheet of polyester transparent film is laminated to each side of the foil by passing through squeeze rollers at a pressure of 2000 lb/in. The laminated sheet is then cut into filaments of the required size.

Metallizing process. ► The

equipment consists of a vacuum chamber containing an argon gas. The cathode is the source of the coating material and anode acts as a substrate holder. The movement of electrons occurs from cathode to anode due to the application of 1000 VDC. The electrons ionize the argon gas. The argon ions are accelerated toward the cathode. The bombardment of the energetic ions on the cathode results in a transfer of momentum. If the kinetic energy of the striking ion is higher than the binding energy of the surface atoms of the target, atoms are dislodged or sputtered from its surface by a series of collisions.

SLITTING OPERATION It consists of two steps: ► Rough ► Micro

Slitter

Slitter

Rough Slitter ► Rough

slitter cuts the large polyester sheet

into Pancakes. The width of the each Pancake is 54mm. Cutters of different size are used for this operation, for example 0.2mm, 0.23mm, 0.25mm, etc. Pancakes are also in the form of rolls supplied to the Micro Slitter.

MICRO SLITTER ► The

Micro Slitter consists of both slitter

and winder. In this operation Pancakes are converted into numbers of tape filaments. It has two main parts, ► Cutting

Mechanism

► Winding

Mechanism

Cutting Mechanism ►

The cutting mechanism consists of two parallel shafts. On each shaft blades are mounted side by side such that the edge of one blade on one shaft slightly touches the edge of the blade mounted on the other shaft.

Winding Mechanism ► The

winding mechanism consists of

number of winding positions. The winder is driven by a separate motor. The traverse mechanism is also provided for obtaining the parallel wound package.

Physical Characteristics Polyester Polyester laminated foil metallized Appearance

flat, ribbon-like flat, ribbon-like

width Tenacity Elongation Elastic Recovery

0.2-1 mm 6.2 cN/tex 140 % 50 % at 5 % elongation

0.2-1 mm 11.0 cN/tex 140 % 100 % at 5 % elongation

Abrasion Resistance

good

excellent

Effect of M. R

0.5 %

0.25 %

General Properties ► Generally ► Good

good resistance to acids.

resistance to weak alkalis.

► Not

affected by sea water, chlorinated water, or perspiration.

► Good ► Not

resistant to bleaches.

attacked by ethyl-alcohol, methyl alcohol, perchloroethylene and white spirit.

► It

should be ironed at temperatures up to 130°C.

► It

may be washed at temperatures up to 70°C.

►Fields

of Applications

Cut Resistant Gloves

Antistatic Filter

Anti Static Brush

Fabric: 94% cotton, 6% metallic fibres

Metallic Fibre Sweater

Metallic Fibre Handbag & Shoes