GB/T 39375-2020 PDF in English
GB/T 39375-2020 (GB/T39375-2020, GBT 39375-2020, GBT39375-2020)
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GB/T 39375-2020 | English | 105 |
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Leather - Physical and mechanical tests - Determination of dimensional change
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Standards related to (historical): GB/T 39375-2020
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GB/T 39375-2020: PDF in English (GBT 39375-2020) GB/T 39375-2020
GB
NATIONAL STANDARD OF THE
PEOPLE’S REPUBLIC OF CHINA
ICS 59.140.30
Y 46
Leather - Physical and Mechanical Tests -
Determination of Dimensional Change
(ISO 17130:2013, MOD)
ISSUED ON: NOVEMBER 19, 2020
IMPLEMENTED ON: JUNE 01, 2021
Issued by: State Administration for Market Regulation;
Standardization Administration of PRC.
Table of Contents
Foreword ... 3
1 Scope ... 5
2 Normative References ... 5
3 Principle ... 5
4 Instruments and Materials ... 6
5 Sampling and Preparation of Specimen ... 6
6 Test Procedures ... 7
7 Representation of Result ... 8
8 Test Report ... 9
Leather - Physical and Mechanical Tests -
Determination of Dimensional Change
1 Scope
This Standard specifies the method for measuring dimensional changes of the leather.
This Standard is applicable to the determination of dimensional changes of various
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 document.
GB/T 16991 Textiles - Test for Colour Fastness - Colour Fastness and Ageing to
Artificial Light at High Temperatures: Xenon Arc (GB/T 16991-2008, ISO 105-B06:1998,
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)
QB/T 5250 Leather – Tests for Colour Fastness - Change in Colour with Accelerated
Ageing (QB/T 5250-2018, ISO 17228:2005, MOD)
3 Principle
The leather specimen was subjected to aging treatment according to the provisions of
QB/T 5250, and then air-conditioned again to determine its shrinkage performance.
5250.
6.4 When necessary, the distance between the reference points can be measured
according to 6.1 immediately after the aging treatment test (up to no more than 5min)
after the sample has been aging, calculate the results, which shall be indicated in the
report.
6.5 Readjust the specimen for at least 48h according to the provisions of QB/T 2707.
6.6 Re-measure the lengths of AB, BC, CD and DA on each specimen according to 6.1
and record them as α2, b2, c2, and d2, respectively.
6.7 When necessary, record the changes in the appearance, elasticity, softness, and
hand feel of the specimen.
7 Representation of Result
7.1 Representation
The dimensional change is expressed in terms of "linear shrinkage rate" (see 7.2) or
"area shrinkage rate" (see 7.3); and the result is the arithmetic mean of the "linear
shrinkage rate" or "area shrinkage rate" of each specimen; and expressed as a
percentage (%), and accurate to 0.1%.
7.2 Linear shrinkage rate
The linear shrinkage rate of the specimen is calculated according to Formula (1):
Where:
SL – linear shrinkage rate, expressed by %;
α1 – Length of AB before aging treatment, in mm;
b1 – length of BC before aging treatment, in mm;
c1 – length of CD before aging treatment, in mm;
d1 – length of DA before aging treatment, in mm;
α2 – length of AB after aging treatment, in mm;
b2 – length of BC after aging treatment, in mm;
...... Source: Above contents are excerpted from the PDF -- translated/reviewed by: www.chinesestandard.net / Wayne Zheng et al.
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