Dimensional stability to washing test somewhere it is called as shrinkage test. It is a textile testing process for checking the change of fabric dimension. And It is developed by American Association of Textile Chemist & Colorist ( AATCC). The method number is AATCC 135. Details has been given at below.
Purpose and Scope
This test method is for the determination of dimensional changes of fabrics when subjected to home laundering procedures.
This test is applicable to all fabrics suitable for home laundering.
Apparatus and Materials
- Standard washing machine
- Standard tumble dryer or facilities for drip/line drying.
- Conditioning facilities and conditioning/drying racks with pull-out, perforated shelves
- Balance with at least 5.0-kg or 10.0-lb capacity.
- AATCC 1993 Standard Reference Detergent
- Laundering ballast, Type 1 or Type 3
- Indelible ink marking pen
- Suitable rule, tape, marking template or other marking device
- Measuring devices.
- Tape or rule marked in millimeters, eighths or tenths of an inch.
- Tape or ruled template marked directly in percent dimensional change to 0.5% or smaller increment
Prior to marking, condition test specimens as at the environment of temperature 21±1 & RH 65%±5%
Lay each test specimen flat, separately, on a screen or perforated shelf of a conditioning rack
Lay the sample on a flat surface. Do not allow any section of the sample to hang over the edge of the work table.
Using a template for the selected test size, mark specimens parallel to the selvage or fabric length direction. Avoid use of the sample area within ten percent of the sample width.
Mark each 380×380 mm
(15 × 15 in.) test specimen with three 250-mm (10-in.) pairs of benchmarks parallel to the test specimen length and three 250 mm (10 in.) pairs of bench-marks parallel to the test specimen width.
Mark each 610×610 mm(24.0 × 24.0 in.) test specimen with three 460-mm (18.0-in.) pairs of benchmarks parallel to the test specimen length and three 460-mm (18.0-in.) pairs of bench-marks parallel to the test specimen width.
For test specimens greater than 125 mm and less than 380 mm (15 in.) wide, take full width of test fabrics and cut each specimen 380 mm long. Mark the length Measurement of the width is optional.
Select washing conditions for testing as per below table
|Cycle||(1) Normal||(2) Delicate||(3) Permanent Press|
|Wash Temp, °C (°F)1||Cold: 27 ± 3 (80 ± 5)||Cold: 27 ± 3 (80 ± 5)||Cold: 27 ± 3 (80 ± 5)|
|Warm: 41 ± 3 (105 ± 5)||Warm: 41 ± 3 (105 ± 5)||Warm: 41 ± 3 (105 ± 5)|
|Hot: 49 ± 3 (120 ± 5)||Hot: 49 ± 3 (120 ± 5)||Hot: 49 ± 3 (120 ± 5)|
|Very Hot: 60 ± 3 (140 ± 5)||Very Hot: 60 ± 3 (140 ± 5)||Very Hot: 60 ± 3 (140 ± 5)|
- Set washing machine controls to generate the selected cycle parameters.
- Load for laundering shall consist of all specimens in the sample, plus enough laundering ballast pieces to make a total load weight of 1.8 ± 0.1 kg.
- Begin selected wash cycle. Allow machine to fill to specified water level.
- Add 66 ± 1 g of AATCC 1993 Standard Reference Detergent to washing machine as directed by washing machine manufacturer’s instructions. If detergent is added directly to wash water, agitate briefly to dissolve completely.
- Stop agitation before adding wash load.
- Add wash load (test specimens and ballast), distributing evenly
- around center agitator.
- Restart wash cycle.
- For specimens to be drip dried, stop wash cycle before the water begins to drain from the final rinse cycle. Remove specimens soaking wet.
- For specimens to be tumble or screen/flat dried, allow washing to proceed through the final spin cycle.
- After each washing cycle, separate tangled specimens and ballast pieces, taking care to minimize distortion. Proceed to appropriate drying procedure.
Select drying conditions from below table
Standard Drying Conditions
- Tumble Dry
(Ai) Tumble Dry Normal
(Aii Tumble Dry Delicate
(Aiii) Tumble Dry Permanent Press
- Line/Hang Dry
- Drip Dry
- Screen Dry/Dry Flat
- Place the washed load (test specimens and ballast) in the tumble dryer, and set the temperature control to generate the selected cycle exhaust temperature (see Table III).
- Allow the dryer to run until the load is fully dry. Remove specimens immediately.
- Hang each specimen by two corners, with the fabric length in the vertical direction. Allow specimens to hang in still air at room temperature not greater than 26°C (78°F) until dry.
- Do not blow air directly on specimens as it may cause distortion.
Hang each dripping wet specimen by two corners, with the fabric length in the vertical direction. Allow specimens to hang in still air at room temperature not greater than 26°C (78°F) until dry. Do not blow air directly on specimens as it may cause distortion
Screen/Flat Dry :
- Spread each specimen on a horizontal screen or perforated surface, removing wrinkles without distorting or stretching it.
- Allow specimens to rest in still air at room temperature not greater than 26°C (78°F) until dry.
- Do not blow air directly on specimens as it may cause distortion.
- For all drying methods, allow specimens to dry completely before washing again.
- Repeat the selected washing and drying procedures for a total of 3 complete cycles, or an agreed upon number of cycles.
After the final drying cycle is complete, condition test specimens as required
- After conditioning, lay each test specimen without tension on a flat smooth, horizontal surface.
- Measure and record the distance between each pair of benchmarks to the nearest millimeter, eighth or tenth of an inch. This is measurement B.
- The wrinkles in most fabrics flatten sufficiently under pressure of a measuring instrument at the time of measurement not to cause measurement bias.
Calculation and Interpretation
- If measurements were made directly in percent dimensional change, average the measurements in each direction made on the specimens after the first, third, or other specified number of washing and drying cycles. Calculate length and width averages separately to the nearest 0.1%.
- If measurements were made to the nearest millimeter or eight or tenth of an inch, calculate the dimensional change after the first and third or other specified washing and drying cycle using equation 1:
Average% DC = 100 (B – A)/A (1)
DC = Average dimensional change
= Average original dimension
= Average dimension after laundering
- Both the average original and average final dimensions are the averages of the measurements in each direction made on all test specimens. Calculate length and width averages separately to the nearest 0.1%
- A final measurement smaller than the original measurement results in a negative dimensional change, which is shrinkage.
- A final measurement larger than the original measurement results in a positive dimensional change, which is growth.
- Report for each sample tested:
- A description or identification of the sample.
- Evaluation was performed using AATCC Test Method 135-2018.
- Standard detergent used, i.e., AATCC 1993 Standard Reference Deter-gent with or without optical brightener.
- Number of laundering cycles (default is 3 cycles)
- Laundering conditions, including washing machine cycle, wash temperature, drying procedure and tumble drying temperature
- Any modifications of the test method. If laundering equipment or conditions other than those specifically listed in the test method were used, they must be described in detail and noted as a modification of the standard method.
- Average dimensional change, to the nearest 0.1%, with a minus sign (-) for shrinkage or a plus (+) sign for