FZ/T 70009-2021 Test method for relaxation dimensional change and felting dimesional change to washing of wool textiles
1 Scope
This document specifies the test method for determining the dimensional change percentages to washing of wool textiles.
This document is applicable to washable (hand or machine washable) knitted wool products, knitted wool patchwork garments, and woven wool fabrics.
2 Normative references
The following documents contain provisions which, through reference in this text, constitute provisions of this document. For dated references, only the edition cited applies. For undated references, the latest edition (including any amendments) applies.
GB/T 6529 Textiles - Standard atmospheres for conditioning and testing
GB/T 7477 Water quality - Determination of the sum of calcium and magnesium - EDTA titrimetric method
GB/T 8170 Rules of rounding off for numerical values & expression and judgment of limiting values
GB/T 8629-2017 Textiles - Domestic washing and drying procedures for textile testing
FZ/T 70008 Test method for cover factor of wool knitted fabrics
3 Terms and definitions
For the purposes of this document, the following terms and definitions apply.
3.1
relaxation dimensional change
dimensional change of a sample due to release of stress incurred during processing when washed
3.2
felting dimensional change
dimensional change of a sample due to wool fiber entanglement and felting during washing
3.3
total dimensional change
dimensional change of a specimen after undergoing both relaxation and felting washing procedures
3.4
cuff edge dimensional change
dimensional change on the folded edges of a specimen in both length and width directions
3.5
relaxation dimensional change percentage
percentage of dimensional change of a specimen after undergoing the relaxation washing procedure relative to its original dimension
3.6
felting dimensional change percentage
percentage of dimensional change of a specimen after undergoing the felting washing procedure relative to its original dimension before the felting washing procedure
3.7
total dimensional change percentage
percentage of dimensional change of a specimen after undergoing both the relaxation and felting washing procedures relative to its original dimension
3.8
area dimensional change percentage
percentage of area dimensional change of a specimen after undergoing the washing procedure relative to its original area before the washing procedure
3.9
cuff edge dimensional change percentage
percentage of cuff edge dimensional change of a specimen after undergoing the felting washing procedure relative to its original dimension before the felting washing procedure
3.10
differential cuff edge dimensional change percentage
difference between cuff edge dimensional change percentage and felting dimensional change percentage of a specimen
4 Principle
After undergoing the specified washing procedure, the dimensional changes of the specimen before and after washing are measured, and the relaxation dimensional change percentage, felting dimensional change percentage, total dimensional change percentage, etc., are calculated.
5 Instruments, materials and tools
5.1 Washing machine
According to GB/T 8629-2017, an A-type washing machine is selected that meets the conditions of the 4G and 4N washing procedures.
5.2 Oven
Capable of maintaining a constant temperature of (50±5)℃.
5.3 Knitting machine
Capable of knitting single-jersey fabrics with appropriate cover factors.
5.4 Yarn length tester
As specified in FZ/T 70008.
5.5 Water tank
With dimensions of at least 600mm×600mm and a depth of 50mm, featuring a flat bottom to facilitate wet state measurements of specimens.
Note: Other instruments capable of wet state measurements may also be used.
5.6 Counterweight fabric
Double-layer polyester knitted fabric, with each layer measuring (300±30)mm in length and width, weighing (35±5)g, and sewn on all four sides.
Foreword I
1 Scope
2 Normative references
3 Terms and definitions
4 Principle
5 Instruments, materials and tools
6 Atmospheres for conditioning and testing
7 Specimen preparation
8 Test procedures
9 Calculations
10 Test report
Annex A (Normative) Description of visual defects
