MICRO- FIBRE

MICRO-FIBRE AND ITS PROCESSING 

Micro-fibre is a synthetic fibre finer than 1 denier.

According to PET COUNCIL in US it's a type of fibre which is 4 times finer than wool, 3 times than cotton and 2 times as twice as silk. Most common type of micro-fibre are made from Polyester, Polyamides or combination of PET, Poylamide and Polypropylene -- PROLEN.

It is distinguished  by its softness, toughness, drapablity and high degree of comfort to wearer.

TYPES OF MICRO-FIBRE

1. SUPER MICRO-FIBRE - less than 0.3 dtex.

1. MICRO-FIBRE - 0.3-1 dtex

PROPERTIES OF FABRIC MADE FROM MICRO-FIBRE:

• Finer diameter

• Greater bulk

• Light weight

• High cover factor

• Excellent softness and drape

• Dimensional stability

• Silky handle and good comfort

• Good water vapor permeability

• Better durability and easy care

• Excellent thermal insulation

PROCESSING OF MICRO-FIBRE

PRE-TREATMENT

 This is utmost important step because fabric interstices are very small. Therefore higher size add is required due to dense weave and greater surface area.Thus due to all this removal of size also become difficult.

DESIZING

This is carried out to remove the size add on to the micro-fibres.  It's done in open width washer under tension less condition. 

 PROCESS:

It's carried out with H2O2(3g/l), Na2CO3 (4 g/l), deformer (0.5 gpl), detergent (2gpl) and NaSio3 (0.05gpl).

NOTE: BEFORE DESIZING IDENTIFICATION OF SIZING IS MUST.

BLEACHING

Chlorine beach may be carried out with NaClo2 (1-3gpl), NaNo2( 1-3gpl), HCOOH (1-3 gpl to get pH around 4) at 90 degree for 1 hr followed be hot wash, neutralization with Na2Co3 for 5-10 min at 90-95 degree, through cold washing, anti-chloring and final washing.

HEAT SETTING

Its carried out before dyeing at 180 degree for 30-45s for 100% PET microfibre plainn warps; in case no plain warps are avalilable heat setting is omitted but dried at 140-150 degree. Pre-setting is required to  hinder crease mark during dyeing and to prevent shrinkage.

EMERISING

This is done:

• To make smooth surface and give luxurious handle.

• To increase the fabric economical value.

   PROCESS: Fabric is made to pass over the rollers coated with emery paper with 300-500 grade.

Here process parameters should be carefully controlled otherwise 60% of tensile loss takes place. Speed of roller is generally around 15-20m/min. After this heat setting is done at 160-180 degree followed by jet washing to remove the fibre dust.

DYEING:

In microfibre dyeing, as denier goes down surface area increases. Thus more amount of dye is needed to obtain a particular shade as compared to dyeing of conventional PET.

Disperse Dyes are used.

Jet dyeing machine is used.

Dyeing is started at 60 degree with deaerating agent, levelling agent, lubricant and CH3COOH( pH: 4.5-5.0): fabric is loaded and run for 10min. Dyebath is then heated up @<1degree/min upto 96 degree and hold at this temp for 20 min followed by further heating at the same rate up to 130 degree and dyeing is carries out for 1 hr. Cooling is done @1degree/min up to 70degree, the bath is drained and washed thoroughly. Reduction clearing is done at 70 degree with sodium hydrosulphite and soda ash for 15 min, rinsed, neutralized with acetic acid to improve fastness properties.

DIS- ADVANTAGE OF MICRO-FIBRE

• Processing aids are required in large quantity due to high surface area.
• Washing is difficult because of large number of small interstices present. Thus complete removal is difficult.
• Needs efficient scouring.
• Difficult to obtain deep shades.