Study on color fastness to rubbing by Crockmeter.

Presented by : Presented by : Hasibul Haque ChowdhuryHasibul Haque Chowdhury

B.Sc. in Textile Engineering B.Sc. in Textile Engineering DUETDUET

IntroductionIntroductionRubbing means friction. Fastness towards friction. It is

measured by an instrument called Crock Meter. The fabric we use everyday is always gone through rubbing action by different ways hence the color of the fabric is faded down.

Details on Crock MeterCrocking is a transfer of colorant from the surface of a

colored yarn or fabric to another surface, or to an adjacent area of the same fabric, principally by rubbing. Crock meter which is worked by creating an artificial friction. To measure the rubbing fastness of the fabric, crock meter is used.

This is done both in dry & wet condition and the corking cloth is used with the sample in crock meter. The sample is gone through rubbing action in the crock meter and after rubbing color change and color staining is assessed with the help of grey scale.

Standard Test MethodMETHOD ISO 105X12/

AATCC8ISO105X16/AATCC 116

AATCC 165

APPARATUS CROCK METER ROTORY VERTICAL CROCK METER

CROCK METER

DIMENSION OF RUBBING FINGER

(19x25.4)mmBlock for pilefabrics

2.5 cm (19x25.4)Mm block

DOWN WARD FORCE

(9±0.2) N 11.1N±10% (9±0.2)N

WEFT PICK UP IN WET RUBBING

95–100%in ISO/65%+5%inAATCC

95–100% in I SO/65%in AATCC

95–100%inISO/65%inAATCC

NO OF CYCLE/TURN

10 TIMES IN SECS

ABOUT 40 RECIPROCAL TURNS

10 TIMES IN 10 SECS

Apparatus and Material Used in ISO 105/AATCC 8

Crock Meter

Cotton Rubbing Fabric

Grey Scale

Stop Watch

Weight (9N)

Color Matching Cabinet

Conditioning1. At first cut the specimen in ( 5*5) cm.2. The sample has to be tested in the delivered condition.3. The fabric/sample has to be air conditioned at least 8 hours by standard climate (20°C / 65% relative humidity).4. The air conditioned specimen has to be rubbed with the dry and wet cotton rubbing cloth in warp, weft or diagonal direction on face side. The test direction has to be noted in the test report.

Use always cotton test material from James Heal (Cotton Rubbing cloth ISO 105 F09)

For a correct test result the rubbing point on cotton must show an even staining with an exact circle

Sample Preparation The size of the plate of the crock meter is 22cm x 8cm;

hence the sample size is 22cm x 8cm. Two samples are taken-one for dry state; one for wet

state, rubbing action is done on the both side of the sample.

The color change is assessed in the sample with grey scale & the color staining is assessed in the crocking cloth with the help of grey scale.

The same procedure is followed for the wet condition& the rating for color change& color. staining is assessed.

Dry Sample Test Use the holding clamp to mount the specimen on the based board

of the crock meter . The long direction of the specimen is parallel to the track of rubbing .Ensure the specimen lays flats on the based board.

Two test are performed .One along the direction of warp/length and the other of the weft/width.

Mount a dry rubbing cloth flat over the end of the peg on the crock meter and hold it taut by means of the spring clip provided.

Rest the finger on the specimen, ensuring that the spring clip is not in contact with the test specimen.

Rub the specimen back and forth over a straight track 100mm+/- 8mm long for 10 complete cycle at a rate of 1 second for each cycle.

It may be necessary to stretch some fabric on to the based of the crock meter ,to prevent the fabric from rubbing up.

Wet Sample Test Mount test specimen on Crockmeter base. Bring wet pick up of square to 65% ±5% Mount crock square on peg Lower peg onto specimen Turn crank handle 10 times Air dry and condition crock square Remove loose fiber Evaluate

Evaluation for result

Dry sample : 4/5 and Wet sample : 3Here numerical value between 1 to 5

Thank You