PILLING AND ABRASION TESTING

Submitted to:

Dr.Ashvani Goyal

Assistant Professor

Submitted by:

Chaitanya Chaudhary

12TT016

PILLING AND ABRASION TESTING

• Pilling:-• A garment is considered to be serviceable when it is fit for its particular end use.

1. It is a fabric surface fault characterized by little pills of entangled fibre clinging to the cloth surface and giving the garment an unsightly appearance.

2. Formed by rubbing action on loose fibres that are present on the fabric surface.

3. Stronger component in the blend aggravated its seriousness.

4. Higher breaking strength and lower bending stiffness results more pill.

5. Low twist factor, higher hairiness, and loose fabric structure results easy and large pills.

MEASUREMENT OF FABRIC PILLING:• a) Objective method: • Counting the number of pills or by removing and

weighting them.But this is a time consuming job and also does not take into account the degree of colour contrast with the ground.

• b) Subjective method: By comparing it with either standard sample or with photograph or by use of written scale of severity

METHODS OF MEASUREMENT:1. ICI pilling box

2. Random tumbling pilling test

3. Pilling test by Martindale Abrasion Tester

4. ICI pilling box:

• A specimen (125 mm x 125 mm) is cut from fabric (2 for warp 2 for weft).

• Stitched face-to-face and turned inside out.

• The fabric tube is then mounted on rubber tubes.

• The loose ends taped with PVC tape.

• All the four samples are then tumbled together in a cork-lined box 9'' x 9'' x 9'' and allowed for required revolution cycle.

• The specimens are taken out and removed from rubber tube and rated.

• Also, pilling is mainly due to fibres with very high “lateral strength” or "bending strength" or “low brittleness”

SPECIFICATIONS:-

• High “lateral strength” may be advantageous in some applications like technical textiles, floor covering, etc.

• However, the pilling tendency also increases, so in the apparel sector “low lateral strength" is preferable, particularly in knitted goods.

• Polyester fibres are deliberately made brittle for use in knitted products to avoid pilling (anti pilling types).

• Pills do not form where fibres with low lateral strength are used (wool and anti-pill man-made fibres).

• They can be easily scrubbed off.

• But fibres with “high lateral strength” will have higher pilling tendency.

• Pilling resistance and durability are inversely related.

PILLING GRADES:• Grade 5 No or very weak formation of pills.

• Grade 4 Weak formations of pills.

• Grade 3 Moderate formations of pills.

• Grade 2 Obvious formations of pills.

• Grade 1 Severe formation of pills.

• 2. .Random tumbling pilling test:• Random tumbling motion produced by tumbling specimen in a cylindrical test chamber lined with mildly abrasive

material.• To resemble the pills those with actual wear, small amount of cotton lint are added.• Three specimen of 105 mm x 105 mm are cut an angle 45º to length and edges are sealed with rubber adhesive.• All these samples along with cotton lint are tumbled in the test chamber.• After certain time the fabric samples are assessed. The number and timing of the cycles depends on type of fabric

being tested and would be laid down in the relevant specification.

3.PILLING TEST BY MARTINDALE ABRASION TESTER:• The specimens are mounted on large (bottom) and small (top) specimen holder.

• Then rubbed against each other (source sample).

• Two pressures are used : 2.5 cN/cm knitted fabric.

• 6.5 cN/cm for woven and upholstery fabric.

• In place of std. abradant, the fabric sample is placed in the lower holder.

• If the degree of pilling is different on the upper and lower holder, the upper specimen is assessed.

• The number and timing of the cycles depend on the type of fabric tested and would be laid down in the relevant specification.

ABRASION RESISTANCE• Abrasion is the rubbing away of the component fibers and yarns of the fabric.

• Abrasion is of three types :• Plain or flat abrasion - A flat area of material is abraded.

• Edge abrasion - Kind of abrasion which occurs at collars and folds.

• Flex abrasion - Rubbing is accompanied by flexing and bending.

FACTORS AFFECTING ABRASION RESISTANCE• 1. Fibre type:

• High elongation, elastic recovery, and work of rupture are considered to be more important factors. (Nylon polymer) Blending of nylon or polyester with wool or cotton improves abrasion resistance.

• 2. Fibre properties:

• Longer fibres incorporated into fabric confer better abrasion resistance, because they are harder to remove from yarn. For the same reason filament yarns are more abrasion resistant than staple yarns made from the same fibre. Increasing fibre diameter up to a limit improves abrasion resistance. Above the limit the increasing strains encountered in bending counteract any further advantage and also a decrease in the number of fibres in the cross-section lowers fibre cohesion.

• 3. Yarn twist:• Optimum twist increases the abrasion resistance. At low twist, fibres can come out and at high twist more

abrasion due to stiffer yarn.

• 4. Fabric structure:

• If one set of yarn is predominantly on the surface then this set will wear most. Relative mobility of floats helps to absorb the stress.

METHOD OF MEASUREMENT:

• MARTINDALE ABRASION TESTER:• Four specimens (38 mm diameter) are mounted in the specimen

holder.

• The sample is abraded against standard abradant under standard load.

• A complex motion (resultant of two s.h.m. at right angle to one another) is given to the specimen holder.

ASSESSMENT:

No. of cycles are noted when two threads are broken. The specimen is examined at suitable intervals. If likely failure point is known, then first inspection can be made at 60% of that value.

Average rate of loss is mass:• Total eight specimens, out of that two specimens abraded up to two thread break.

• Other pairs are abraded upto 25%, 50%, and 75% of the above and average loss in weightt can be measured from a plot of loss in mass vs cycle (loss in mass in mg/1000 rubs).

For hosiery fabrics, a flattened rubber ball is pushed through the sample as the holder is tightened thus stretching it. Tested at 12kpa pressure till hole appears.

THANK YOU