GB/T 40936-2021 PDF in English
GB/T 40936-2021 (GB/T40936-2021, GBT 40936-2021, GBT40936-2021)
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Leather -- Physical and mechanical tests -- Determination of water repellency of garment leather
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Standards related to (historical): GB/T 40936-2021
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GB/T 40936-2021: PDF in English (GBT 40936-2021) GB/T 40936-2021
NATIONAL STANDARD OF THE
PEOPLE’S REPUBLIC OF CHINA
ICS 59.140.30
CCS Y 46
Leather - Physical and mechanical tests - Determination of
water repellency of garment leather
(ISO 17231:2017, MOD)
ISSUED ON: OCTOBER 11, 2021
IMPLEMENTED ON: MAY 1, 2022
Issued by: State Administration for Market Regulation;
Standardization Administration of PRC.
Table of Contents
Foreword ... 3
1 Scope ... 5
2 Normative references ... 5
3 Terms and definitions ... 5
4 Principles ... 5
5 Instruments and materials ... 6
6 Sampling and sample preparation ... 8
7 Test steps ... 9
8 Calculation of the results ... 9
9 Test report ... 10
Appendix A (Informative) Changes in the structure of this document compared to ISO
17231:2017 ... 11
Appendix B (Informative) The technical differences (including their reasons) between
this document and ISO 17231:2017 ... 12
Appendix C (Normative) The pictures of spray rating ... 14
Leather - Physical and mechanical tests - Determination of
water repellency of garment leather
1 Scope
This document describes test methods for the water repellency of garment leather.
This document is applicable to the determination of the water repellency of various
types of garment leather. It can be referred to in the determination of other types of
leather.
2 Normative references
The following documents are essential to the application of this document. For the dated
documents, only the versions with the dates indicated are applicable to this document;
for the undated documents, only the latest version (including all the amendments) is
applicable to this standard.
GB/T 6682 Water for analytical laboratory use -- Specification and test methods
(GB/T 6682-2008, ISO 3696:1987, MOD)
GB/T 39364 Leather - Chemical, physical, mechanical and fastness tests - Sampling
location (GB/T 39364-2020, ISO 2418:2017, MOD)
QB/T 2707 Leather -- Physical and mechanical tests -- Sample preparation and
conditioning (QB/T 2707-2018, ISO 2419:2012, MOD)
3 Terms and definitions
The following terms and definitions apply to this document.
3.1 Spray rating
The degree of the water repellency of a leather surface.
4 Principles
Install the sample on the ring holder, and keep the holder at an angle of 45° with the
horizontal; make the center of the sample be a certain distance below the nozzle. Use a
the outer ring and the inner ring. During the test, place the holder on a fixed base, and
make it form an angle of (45.0±2.5)° with the horizontal; the center of the sample shall
be located (150±2) mm below the center of the metal nozzle’s surface.
5.5 The die knife shall meet the requirements of QB/T 2707, and the inner wall shall be
a square with a side of (182±2) mm.
5.6 Balance shall be accurate to 0.001 g.
5.7 The distilled water or the deionized water shall be in line with the provisions of the
third-grade water in GB/T 6682.
5.8 Filter paper or other equivalents shall be prepared.
6 Sampling and sample preparation
6.1 Sampling
Carry out in accordance with the provisions of GB/T 39364. If it is not possible to
sample from standard parts (such as sampling directly from clothing), it shall be taken
from any part of the sample’s available surface. The samples shall be representative and
indicated in the test report.
6.2 Preparation of samples
Use a die knife to cut out 3 square samples with a side of (182±2) mm; ensure that there
are no holes, folds, creases, or other damages on the samples.
Note 1: When testing sheep leather with wool, in order to clamp the sample firmly, the wool can be
sheared off.
Note 2: If there are more than 2 pieces of leather in the same batch to be tested, cut one sample from each
piece of leather to be tested, and the total number of samples shall not be less than 3.
6.3 Samples’ adjustment in the air
Carry out in accordance with the provisions of QB/T 2707; weigh the sample after
adjustment, and the mass shall be accurate to 0.001 g.
6.4 Test conditions
The test shall be carried out at a temperature of (20±2) °C or (23±2) °C. There are no
requirements for humidity.
mw --- The amount of water absorbed by the sample, in grams (g);
m2 --- The mass of the sample after testing, in grams (g);
m1 --- The initial mass of the sample, in grams (g).
Calculate the water absorption rate of the sample w according to formula (2); use the
arithmetic mean of the three samples’ water absorption rates as the result, and it shall
be accurate to 0.1%.
Where:
w --- The sample’s water absorption rate (%);
mw --- The amount of water absorbed by the sample calculated according to formula
(1), in grams (g);
m1 --- The initial mass of the sample, in grams (g).
9 Test report
The test report shall contain the following:
a) The number of the document;
b) The detailed information of the sample; if the sampling is inconsistent with GB/T
39364, explain the situation;
c) The test conditions (standard atmosphere: 20 °C/65%, 23 °C/50% or 27 °C/65%);
d) The spray rating of each sample (7.4);
e) The wetting status of the back of the sample’s test surface (7.5);
f) The amount of water absorbed by the sample mw;
g) The water absorption rate of the sample w;
h) Any deviation from the provisions of this method;
i) Anomalies in the test.
......
Source: Above contents are excerpted from the PDF -- translated/reviewed by: www.chinesestandard.net / Wayne Zheng et al.
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