Man-made fiber – Test method for thermal shrinkage of filament yarns (after treatment)
1 Scope
This standard specifies the test methods for boiling water shrinkage and dry-hot air shrinkage (after treatment) of man-made filament yarns, i.e., skein method and single-end method. The skein method provides two forms of measurement: manual and automatic types. In case of dispute, manual measurement procedure is to be used.
This standard is applicable to man-made filament yarns of linear density less than 3000 dtex.
This standard is not applicable to partially oriented yarns.
2 Normative references
The following referenced documents are indispensable for the application of this document. For dated references, only the edition cited applies. For undated references, the latest edition (including any amendments) applies.
GB/T 4146 (All parts) Textiles - Man-made fibers
GB/T 6502 Sampling method of man-made filament yarns
GB/T 6682 Water for analytical laboratory use - Specification and test methods (GB/T 6682-2008, ISO 3696:1987, MOD)
GB/T 9994 Conventional moisture regains of textile materials
GB/T 14343 Testing method for linear density of man-made filament yarns
FZ/T 50005 Testing method for linear density of spandex filament yarn
3 Terms and definitions
For the purposes of this document, the terms and definitions given in GB/T 4146 (all parts) apply.
4 Principle
Under specific condition, a test specimen is treated in thermal medium (boiling water or dry-hot air). Thermal shrinkage is calculated from variation in length, measured before and after treatment as percentage of the length of original test specimen.
5 Apparatus and materials
5.1 Skein length tester, equipped with:
a) a device for adjusting tension and a reciprocating wire guide device;
b) a device that can adjust the speed to ensure that the tension fluctuates within the allowable range;
c) a reel with a circumference of (1.000 ± 0.002) m;
d) a device to count reel revolutions.
5.2 Skein holder. It is a cylindrical frame, where multiple test specimens can be placed.
Each test specimen has a hook weight of 2.5 cN and a height of at least 600 mm. There is a row of hooks at the upper and lower ends, and the skein is hung between the upper and lower hooks during the test. The upper hook is fixed, and the lower hook is a 2.5 cN hook weight, which frictionlessly rises and falls along the metal wires on both sides.
5.3 Manual length measuring stand, equipped with:
a) vertical measuring scale: with measuring range of 1 m and minimum division value of 1 mm. The upper end is equipped with clips and hooks. The clamping surface of the clamp is flat, and the filament shall not be damaged or slipped. The hook is made of steel wire with a diameter of 2 mm to 3 mm, and the upper end of the outer circle of the steel wire at the yarn hanging place is flush with the zero position of the measuring gauge;
b) a device for applying pretension: the precision of applying pretension is ±10%, and the tension device is a combined weight with a hook or a combined weight with a clip.
5.4 Automatic length tester. It can automatically measure the length of skein before and after thermal treatment, calculate the thermal shrinkage and automatically adjust the tension. It is equipped with a skein holder similar to that in 5.2.
5.5 Water tank. With heating device, it can keep water boiling. The skein holder, if used, shall be in the vertical state when the water-immersed test specimen is placed. When mesh bag or gauze is used, the water volume is at least 40 times that of the mesh bag or gauze.
5.6 Oven. The highest temperature is 250 °C, the temperature control precision is ±3 °C, and the temperature fluctuates from -1 °C to +1 °C. The internal space shall ensure that the skein holder can be placed in a vertical state.
5.7 Auxiliary materials for boiling water shrinkage test.
a) Grade 3 water in accordance with the requirements of GB/T 6682.
b) Drawable mesh bag: 100 mm × 100 mm. The sample is in a loose state when placed in the mesh bag, and the test specimen will not leak out when boiled. One test specimen needs one mesh bag.
5.8 Tension clip. It is used for spandex testing. See Table 3 for specifications.
6 General principles for tests
6.1 Sampling
Foreword i
1 Scope
2 Normative references
3 Terms and definitions
4 Principle
5 Apparatus and materials
6 General principles for tests
7 Test procedures
8 Calculation of results
9 Precision of test results
10 Test report
Annex A (Informative) Structural changes of this standard with respect to ISO 18066: 2015 and ISO 18067:2015
Annex B (Informative) Technical deviations of this standard from ISO 18066: 2015 and ISO 18067: 2015 and their justifications
Annex C (Informative) Method for calculating tension per unit linear density
Annex D (Normative) Calculation method of increased test amount
Annex E (Normative) Method for placing specimens with mesh bags and gauze
Annex F (Informative) Precision of results
