GB/T 26703-2021 (GB/T26703-2021)

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GB/T 26703-2021: PDF in English (GBT 26703-2021)

GB/T 26703-2021
NATIONAL STANDARD OF THE
PEOPLE’S REPUBLIC OF CHINA
ICS 61.060
CCS Y 78
Replace GB/T 26703-2011
Determination of abrasion resistance for top piece of leather
shoes
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 Test equipment and materials ... 5
5 Samples ... 8
6 Test steps ... 9
7 Test results ... 11
8 Test reports ... 13
Appendix A (Informative) Instructions of the grinding machine for Top Piece of leather
shoes ... 15
Appendix B (Informative) Schematic diagram of the spike-teeth used to fix the sample
... 16
Determination of abrasion resistance for top piece of leather
shoes
1 Scope
This document describes two test methods (Method A and Method B) for evaluating the
abrasion resistance of the Top Piece of leather shoes. Method A is the method by using
a rotating cylindrical drum device. Method B is the method by using a reciprocating
abrasion machine.
This document applies to the Top Piece of leather shoes for general use (hereinafter
referred to as “the Top Piece”).
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 533-2008 Rubber, vulcanized or thermoplastic -- Determination of density
GB/T 2703-2017 Footwear -- Vocabulary
ISO 4649:2017 Rubber, vulcanized or thermoplastic -- Determination of abrasion
resistance using a rotating cylindrical drum device
3 Terms and definitions
Terms and definitions defined in GB/T 2703-2017 are applicable to this document.
4 Test equipment and materials
4.1 Method A - using a rotating cylindrical drum device
4.1.1 Rotating cylindrical drum device
The abrasion machine shall comply with the requirements of 5.1 in ISO 4649:2017; a
non-rotating gripper shall be used.
5 Samples
5.1 Method A
5.1.1 Size and number of the test samples
5.1.1.1 The sample shall be a cylinder with a diameter of (16.0 ± 0.2) mm and a
thickness of at least 6 mm.
5.1.1.2 For the samples with a thickness of less than 6 mm, they can be fixed on the
substrate of the same material or with hardness not less than that of the samples, but the
thickness of the samples to be ground shall not be less than 2 mm.
5.1.1.3 There shall be no less than 4 samples in each group. For arbitration purposes,
10 samples are required.
5.1.2 Preparation and conditioning of the samples
5.1.2.1 Select an appropriate preparation method according to the material and size of
the Top Piece.
5.1.2.2 Use a rotary cutter (4.1.5) to cut out the sample. When cutting, add water as
lubricant to the cutting edge of the cutter for lubrication. Blanking is not allowed.
5.1.2.3 When it is not suitable to use a rotary cutter (4.1.5) for sampling, a grinding
machine for Top Piece of leather shoes (4.1.6) may be used to prepare the sample.
Note: This preparation method is suitable for the Top Piece with a small size or high hardness.
5.1.2.4 Use the Top Piece’s side that is in contact with the ground as the test surface,
remove or keep its original pattern (indicated in the test report). If the non-test surface
of the sample is not flat, it shall be smoothed.
5.1.2.5 If the size of the Top Piece is too small to be produced to a complete sample, a
sample can be taken from the processed test piece that is produced by the same formula
as the Top Piece; or directly fix Top Piece on the substrate specified in 5.1.1.2 to form
a combined sample. If necessary, use the grinding machine (4.1.6) to trim the combined
sample. This situation shall be noted in the test report.
Note: For the Top Piece with a pin, it can be directly inserted into the substrate with holes and fixed to
form a combined sample.
5.1.2.6 All samples shall be conditioned for at least 16 h at the temperature of
(23.0±2.0) °C and the relative humidity of (50.0±5.0) % before the test.
5.2 Method B
5.2.1 Size and number of test samples
5.2.1.1 Appropriately cut the sample according to the size of the Top Piece’s area that
is in contact with the ground; it shall be rectangular with a length-width ratio not
exceeding 2:1 or other shapes (such as circles). The optional sizes are shown in Table
1.
5.2.1.2 There shall be no less than 2 samples in each group.
5.2.2 Preparation and conditioning of samples
5.2.2.1 Use the Top Piece’s side that is in contact with the ground as the test surface,
remove or keep its original pattern (indicated in the test report). If the non-test surface
of the sample is not flat, it shall be smoothed. For the Top Piece with a pin, the pin shall
be removed.
5.2.2.2 All samples shall be conditioned for at least 16 h at the temperature of
(23.0±2.0) °C and the relative humidity of (50.0±5.0) % before the test.
6 Test steps
6.1 Method A
6.1.1 The test shall be carried out at the temperature of (23.0±2.0) °C and the relative
humidity of (50.0±5.0) %.
6.1.2 Set the wear stroke of standard rubber (4.1.4) to be (40.0±0.2) m, and carry out
the test according to the provisions of 6.1.3. Before and after each test, the standard
rubber (4.1.4) shall be measured three times respectively; for each test, the mass loss
shall be between 180 mg and 220 mg.
6.1.3 Before each test, use a stiff brush or a vacuum cleaner to remove debris from the
abrasive cloth.
Weigh the mass of the sample, it shall be accurate to 1 mg. Fix the sample on the gripper
of the abrasion machine, and make the length of the sample protruding from the opening
be (2±0.2) mm; the length can be measured with the gauge equipped with the abrasion
machine.
Press the sample on the roller with a vertical force of (10.0±0.2) N.
Move the gripper with the sample from the slideway to the starting point of the roller
and start the machine to carry out the test. If there is abnormal vibration during the test,
the test result is invalid.
After the test, weigh the mass of the sample again, it shall be accurate to 1 mg. The
debris adhering to the sample shall be removed before weighing.
6.1.4 Take a sample for pre-grinding as specified in 6.1.3. Set the pre-grinding stroke
to be (20.0±0.1) m. Calculate the amount of the sample’s wear during pre-grinding.
Select wear stroke of the test according to the amount of the sample’s wear during pre-
grinding:
a) If the amount of the sample’s wear during pre-grinding is less than 200 mg, then
set the wear stroke of the test for the remaining samples to be 40 m;
b) If the amount of the sample’s wear during pre-grinding is greater than 200 mg but
less than 300 mg, then set the wear stroke of the test for the remaining samples to be
40 m. When the stroke reaches 20 m, stop the test, readjust the protruding length of
the sample to (2.0 ± 0.2) mm, and then continue the test to complete the remaining
stroke.
c) If the amount of the sample’s wear during pre-grinding is greater than 300 mg,
then set the wear stroke of the test for the remaining samples to be 20 m (if necessary,
it can be shorter). Finally, convert the result of the wear amount to that when the
wear stroke is 40 m (explain the situation in the test report);
d) After the test, the sample shall not be worn through.
6.1.5 The rest of the samples shall be tested according to the stipulations in 6.1.3 and
the wear stroke determined in 6.1.4.
6.1.6 Determine the density of the sample according to the provisions of Method A in
GB/T 533-2008.
6.2 Method B
6.2.1 The test shall be carried out at the temperature of (23.0±2.0) °C and the relative
humidity of (50.0±5.0) %.
6.2.2 Determine the standard rubber’s mass loss S according to 6.1.3.
6.2.3 Measure the sample’s original thickness h0 with a thickness gauge; it shall be
accurate to 0.01mm.
6.2.4 According to the area of the Top Piece sample that is in contact with the ground,
select a corresponding load to apply to the friction hammer (see Table 1).
6.2.5 Cut out an appropriate size of abrasive cloth (4.2.3), and fix it on the friction table
with the fixing clip.
6.2.6 Change a new abrasive cloth after the test of each sample of the leather shoe’s Top
Piece.
m1 --- The mass of the sample before the test, in milligrams (mg);
m2 --- The mass of the sample after the test, in milligrams (mg).
Take the arithmetic mean of the mass losses of the tested samples (excluding pre-ground
samples) as the result.
7.1.3 The result of the sample’s wear is expressed by the relative volume of wear.
Calculate the relative volume V of the sample’s wear when the wear stroke is 40 m
according to formula (3):
Where:
V --- The relative volume of the sample’s wear, in cubic millimeters (mm3);
m --- The arithmetic mean of the sample’s mass losses, in milligrams (mg);
ρ --- The sample’s density, in milligrams per cubic millimeter (mg/mm3);
S0 --- The fixed mass loss of the standard rubber (200 mg), in milligram (mg);
S --- The arithmetic mean of the standard rubber’s mass losses, in milligrams (mg).
The result of wear is rounded to an integer.
7.2 Method B
7.2.1 Calculate the standard rubber’s mass loss S according to formula (4):
Where:
S --- The mass loss of standard rubber, in milligrams (mg);
M1 --- The mass of the standard rubber before the test, in milligrams (mg);
M2 --- The mass of the standard rubber after the test, in milligrams (mg).
Take the arithmetic mean of 3 calculation results of standard rubber’s mass loss as the
result.
7.2.2 Calculate the sample’s relative thickness loss H according to formula (5):
Where:
H --- The relative thickness loss of the sample, in millimeters (mm);
h0 --- The initial thickness of the sample before the test, in millimeters (mm);
h1 --- The thickness of the sample after the test, in millimeters (mm);
S0 --- The fixed mass loss of the standard rubber (200 mg), in milligram (mg);
S --- The arithmetic mean of the standard rubber’s mass losses, in milligrams (mg).
Take the arithmetic mean of the relative thickness losses of the two samples as the result;
the result shall be accurate to 0.05 mm.
The difference between the relative thickness losses of the two samples shall not be
greater than 10% of the arithmetic mean, otherwise, the test shall be carried out again.
If both the relative thickness losses of the two samples are less than 0.2 mm, there are
no requirements for the data deviation.
8 Test reports
8.1 Method A
The test report for Method A shall include the following:
a) The description of the sample’s style, color, material, etc.
b) The number of this document;
c) The density;
d) The relative volume of wear;
e) The preparation method of the sample (When the size of the Top Piece is too small
to be produced to a complete sample with a diameter of 16 mm);
f) The date of the test;
g) Any deviation from this test method.
8.2 Method B
......
 
(Above excerpt was released on 2022-03-06, modified on 2022-03-06, translated/reviewed by: Wayne Zheng et al.)
Source: https://www.chinesestandard.net/PDF.aspx/GBT26703-2021