GB/T 14337-2022 English PDF (GBT14337-2022)

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GB/T 14337-2022: Man-made fibre -- Test method for tensile properties of staple fibre
GB/T 14337-2022
NATIONAL STANDARD OF THE
PEOPLE’S REPUBLIC OF CHINA
ICS 59.060.20
CCS W 50
Replacing GB/T 14337-2008
Man-made fibre - Test method for tensile properties of staple
fibre
ISSUED ON: APRIL 15, 2022
IMPLEMENTED ON: NOVEMBER 01, 2022
Issued by: State Administration for Market Regulation;
Standardization Administration of the People's Republic of China.
Table of Contents
Foreword ... 3
1 Scope ... 5
2 Normative references ... 5
3 Terms and definitions ... 5
4 Principle ... 5
5 Devices and materials ... 6
6 General test rules ... 7
7 Test steps ... 10
8 Result calculation ... 12
9 Test report ... 14
Annex A (informative) Method to obtain pretension ... 15
Annex B (normative) Calculation of statistical values and number of test pieces
increased ... 16
Bibliography ... 20
Man-made fibre - Test method for tensile properties of staple
fibre
1 Scope
This document describes the test for individual fibre tensile properties of man-made
staple fibres.
This document applies to chemical staple fibres with a nominal length of not less than
20mm.
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 of the referenced document (including any amendments) applies.
GB/T 4146 (all parts), Textiles - Man-made fibres
GB/T 6682, Water for analytical laboratory use - Specification and test methods
GB/T 9994, Conventional moisture regains of textile materials
GB/T 14334, Sampling method for man-made staple fibres
GB/T 14335, Testing method for linear density of man-made staple fibres
3 Terms and definitions
For the purposes of this document, the terms and definitions defined in GB/T 4146 (all
parts) apply.
4 Principle
When the single fibre is under specified conditions, stretch the fibre to break on an
isokinetic extensometer. Obtain the tensile properties data such as breaking force,
breaking strength, breaking elongation, constant elongation force, initial modulus, and
modulus of the specimen from the tensile curve or data acquisition system.
5 Devices and materials
5.1 Constant elongation single fibre extensometer (CRE)
5.1.1 The extensometer shall be equipped with the following devices:
a) A device capable of indicating or recording the tension applied to the specimen
and the corresponding elongation value;
b) A device that can make a stretching curve or a data acquisition system;
c) A gripper suitable for holding individual fibres at the desired nominal gauge length;
d) A device for changing different stretching speeds;
e) A device for precise calibration of the instrument.
5.1.2 The instrument shall meet the following technical requirements:
a) The indication error of applied force shall not exceed 1%;
b) The indication error of elongation does not exceed 0.1mm;
c) The error of clamping length does not exceed 0.2mm;
d) The instrument shall maintain constant elongation. 1s after the force tester is
started, the difference between the speed of the lower gripper and the specified
speed shall not exceed 5%;
e) The gripper shall have adjustment device. It can give the fibre proper clamping
force when clamping the fibre, so as to prevent the fibre from slipping or crushing.
The surface of the gripper jaws in contact with the specimen may have a lining.
Minimize slippage or damage to the specimen within the gripping area;
f) Adjustable automatic grippers shall be used during arbitration;
g) The mass error of the pretension clamp does not exceed 10% of the nominal value.
5.2 Other test tools and materials
5.2.1 Tweezer, fleece board, brush, stopwatch.
5.2.2 Water container, for immersing the specimen in water.
5.2.3 The laboratory water is in accordance with grade three water of GB/T 6682. The
temperature is (20 ± 2)℃.
5.2.4 Nonionic surfactants.
6 General test rules
6.1 Sampling
Sampling regulations are as follows:
- Take loose laboratory samples as needed. The minimum shall not be less than 10g;
- The extraction of laboratory samples in batch samples shall be in accordance with
the provisions of GB/T 14334.
Do not extract the packages that have been accidentally dampened, contaminated,
scratched, or packaged open during transportation.
6.2 Preconditioning, standard atmosphere for humidity conditioning and testing,
humidity-conditioning time
6.2.1 Preconditioning
Preconditioning is required when the sample meets one of the following conditions:
- The moisture regain of the specimen exceeds the official moisture regain;
- The sample is in an atmosphere with a relative humidity higher than the upper limit
of the laboratory relative humidity;
- The sample temperature is 5°C lower than the laboratory temperature.
The preconditioning conditions are that the temperature does not exceed 50℃, the
relative humidity is 10%~25%, and it is placed for at least 30min.
The official moisture regain is specified in GB/T 9994.
6.2.2 Standard atmosphere for humidity conditioning and testing
For staple fibre with a conventional moisture regain less than 4.5%: the temperature is
(20±2)℃, the relative humidity is (65±5)%.
For staple fibre with a conventional moisture regain greater than or equal to 4.5%: the
temperature is (20±2)℃, the relative humidity is (65±3)%.
6.2.3 Humidity-conditioning time
The humidity-conditioning time is according to Table 1. If the staple fibres are pre-
conditioned, the humidity-conditioning time shall be subject to the upper limit. It can
also be weighed every 30min until constant weight.
Table 1 -- Humidity-conditioning schedule for various fibres
Cellulose fibre 3% (test 5% constant elongation force) 5%
7 Test steps
7.1 Determination of linear density
According to the provisions of GB/T 14335, determine the average linear density of the
same laboratory sample or the single fibre linear density of a single specimen.
7.2 Dry state test
7.2.1 Use tweezers to randomly remove a fibre from the conditioned sample. One end
of the fibre is clamped with a tension clamp according to the pretension value in 6.3.1
(when holding the fibre with tweezers and tension clamps, do not touch the test part of
the fibre, and avoid accidental stretching or damage to the fibre). Place the fibre in the
upper holder of the instrument. Ensures fibre elongation in the axial direction. Then
close the lower gripper for the tensile test.
7.2.2 When the specimen is tested, the number of fibre breaks in the jaws (the broken
end cannot be seen when the fibre breaks) or in the gripping head shall not exceed 10%
of the number of test pieces. If it exceeds, check whether the gripper is abnormal. Repair
or replace it. Re-test. If it does not exceed 10%, the results obtained from specimens
with fibres breaking in the jaws or slipping in the gripping head are rejected.
7.3 Wet state test
7.3.1 Samples do not need to be conditioned. Remove a random fibre from the sample
with tweezers. Immerse it in the grade 3 water that is in accordance with GB/T 6682 at
a temperature of (20±2)℃. Add non-ionic surfactants up to a maximum concentration
of 0.1% in water. Submerge the entire specimen. Immersion lasts for 2min.
7.3.2 Remove fibres with tweezers. One end of the fibre is clamped with a tension clamp
according to the pretension value in 6.3.1 (when holding the fibre with tweezers and
tension clamps,...