Measurement of relaxation shrinkage
Relaxation shrinkage is a dimensional change of fabric induced by cold water immersion.
In the test method, the strains in the fabric are released by soaking the fabric without agitation in water that contains a wetting-out agent.
The specimen is conditioned, measured, soaked in water, dried, reconditioned, and measured again.
To measure the Dimensional stability of fabrics, samples are prepared and marked out to be laid them down as per the British standard method.
According to the British standard method, a sample size of 50 cm X 50 cm is prepared (Sample size 30 cm X 30 cm is also considered as a standard measurement.)
4 warp way and 4 weft way samples are prepared of the above size. Three pairs of reference points are made in each direction on the fabric.
The samples are then marked with three sets of marks in each direction, a minimum of 35 cm apart from each other and at least 50mm from all edges.
In the case of the smaller sample, the marks are made 25 cm apart from each other, at a distance of 25 mm from the edge.
Samples are first preconditioned and then conditioned for 24 h in the standard testing atmosphere at a temperature lesser than 5O° C with a relative humidity of between 10% and 25% to achieve a more appropriate result.
Then the sample is laid on a smooth glass surface and covered with another piece of glass to hold it flat while it is measured.
When knitted fabrics are to be tested they are folded to give a double thickness with the free edges sewn together.
It is then soaked flat in a shallow dish for 2 h in water at 15-20° C containing 0.5 g/l of an efficient wetting agent.
It is removed and blotted dry with paper towels without unnecessary handling and allowed to dry flat at 2O° C on a smooth flat surface.
It is then conditioned until equilibrium is reached and remeasured as described above.
The mean percentage value in each direction is relaxation shrinkage.
Relaxation shrinkage = (Original measurement - final measurement) * 100 / Original measurement.
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Questions -
- How relaxation shrinkage is measured?
- Explain the process of measuring relaxation shrinkage of fabric?
References
Booth, J. E. :. (n.d.). Principles of textile testing an introduction to physical methods of testing textile fibres, yarns, and fabrics. London: National Trade Press Ltd,1961. from https://www.abebooks.co.uk/Principles-Textile-Testing-Introduction-Physical-Methods/19989810376/bd
Cenote, M. (2015). Google Books. In The SAGE Guide to Key Issues in Mass Media Ethics and Law (pp. 847–858). SAGE Publications, Inc.
Ferreiro López-Riobóo, J. I. (2015). Long-term (2001–2012) study of a proficiency testing scheme for textiles. Accreditation and Quality Assurance, 20(4), 239–245. https://doi.org/10.1007/s00769-015-1128-1
Patwary, E. M. Z. (2012, May 30). The procedure of dimensional stability test. Textile Fashion Study; Engr. Mohammad Zillane Patwary. https://textilefashionstudy.com/procedure-of-dimensional-stability-test/
Saville, B. P. (1999). Dimensional stability. In Physical Testing of Textiles (pp. 168–183). Elsevier.
What is Fabric Dimensional Stability? How to do the Shrinkage Test? (2017, June 19). Testex. https://www.testextextile.com/fabric-dimensional-stability-shrinkage-test/
