pilling and change of appearance of fabrics

1 Scope

This British Standard describes a method for the determination of the resistance to pilling and change of appearance of apparel fabrics.

NOTE. The titles of the publications referred to in this standard are listed on the insideback cover.

 

2 Definitions

For the purposes of this British Standard the following definitions apply.

2.1 fuzzing. The roughing up of the surface fibres and/or teasing out of the fibres from the fabric, which produces<,j}ange in appearance. This change can occur during washing, dry cleaning or testing.

2.2 pilling. The entangling of fibres into balls (pills) which stand proud of the fabric. This change can occur during washing, dry cleaning or testing. A pill is of such density that light will not penetrate and will cast a shadow.

 

3 Principle

Specimens are mounted on polyurethane tubes and tumbled randomly, under defined conditions, in a corklined box. After an agreed period of tumbling the change in appearance of the specimens is assessed against a rating scale.

 

4 Apparatus

4.1 Pill testing box4, a cubical box with internal dimen~>.before lining, of 235 mm. All internal surfaces of the~t=shallbe lined with cork jointing material of 3.2 mm thickness. The box shall be rotated at 60 ±2 r/min about a horizontal axis passing through the centres of two opposite faces. One side of the box shall be removable for access.

NOTE. Advice on the calibration and comparison of pill testing boxes is given in appendix A.

Cork linings shall be inspected at regular intervals and shall  be replaced when obviously damaged or soiled in such a way as to alter their frictional properties.

4.2 Polyurethane specimen tubes ~, (four), each 140 mm long x 31.5 mm outside diameter x 3.2 mm wall thickness, mass 52.25 ±1.0 g.

4.3 Mounting fig4, to mount specimens on tubes.

4.4 Se/f-adhesive PVC tape4, 19 mm wide.

4.5 Sewing machine.

4.6 Viewing cabinet, which provides high intensity oblique incident illumination (see figure 1) and in which specimens are so mounted that the light casts a shadow across the specimens. The cabinet shall be placed in a darkened area.

 

5 Conditioning and testing atmosphere

The standard temperate atmosphere for conditioning and testing textiles as defined in BS 1051 shall be used, i.e. a temperature of 20 ±2 0C and a rela tive humidity of 65 ±2 %.

 

6 Preparation of test specimens

6.1 Unless otherwise agreed launder or dry clean thesample using a method agreed between the interested parties.

NOTE 1. The procedures described in BS 4923 or BS 4961 Part 1 may be suitable.

NOTE 2. It is recommended to launder or dry clean test specimens to protect the friction surfaces of the pilling box and specimen tubes from lubricants or finishes which may cause inconsistent results.

If laundering or dry cleaning is carried out, assess the specimens before and after treatment using the ratingscheme in 8.2.

6.2 From the sample, cut four specimens, each 125 mm x125 mm. On each specimen mark the back of the fabric andthe length direction. Where a fabric has no discernible face,test both sides.

6.3 Take two specimens and fold each with its face,if discernible, inward and with the machine direction running in the direction of the fold. Sew 12 mm from the cut edges to form a tube, using a stitch density so as to produce a balanced seam. Prepare the other twospecimens similarly withthe cross direction running in the direction of the fold.

6.4 Turn each specimen inside out, so that the fabric face forms the outside of a tube, and cut 6 mm off each end of the fabric tube, thereby removing any sewing distortion.

Using the mounting jig (4.3), mount one prepared specimen on each polyurethane specimen tube (4.2) (see figure 2), so that the specimen ends are an equal distance infrom the ends of the polyurethane specimen tube. EnsWre that the seamed portion lies as flat as possible. Apply self-adhesive PVC tape (4.4) around each of the cut ends of each specimen, so that the tape fixes the specimen onto the tube and leaves 6 mm of the polyurethanespecimentube exposed.

The length of tape on each end of the specimen shall not exceed a length of approximately 1.5 times the circumference of the tube.

6.5 Condition the specimens in the atmosphere specified in clause 5 for at least 16 h. Carry out the test in the same atmosphere.

 

7 Procedure

7.1 Ensure that the inside of the pill testing box (4.1) is clean and free from lint.

7.2 Place the four mounted specimens from the sample in the same pill testing box. Close and firmly secure the lid.

Tumble the tubes in the box for the agreed number of revolutions.

NOTE. No test/wear predictions are available and therefore a suitable number of revolutions needs to be agreed for the particular fabric composition between the parties concerned.

7.3 Remove the specimens from the box, and cut along the seam.

 

8 Assessment of pilling and/or fuzzing

8.1 Mounting of test specimens

Mount the four tested specimens with the length directions vertical on a piece of A4 size card, making sure that the specimens cover the entire card. Attach a piece of the untested sample to the card.

8.2 Assessment

Place the specimen under assessment and a piece of untestedsample centrally on the lectern (see figure 1), with the length direction vertical. If necessary, use a piece of selfadhesive PVC tape (4.4) to ensure correct placement.

View e~clispecimen from just outside the viewing cabinet (4.6) (to prevent glare from the light source) and directly infront ofthe specimen, with the eyes approximately 15 cm to 30 cm above the centre of the specimen.

Rate each specimen in accordance withthe rating schemegiven in table 1. If the rating appears between two gradesreport the result as, for example, 3—A.

 

9 Calculation and expression of results

Record the rating for each specimen and calculate the meanresult. If the mean result is not a whole number express theresult to the nearest half grade, e.g. 3—4, 4, etc.