QB/T 1811-1993 English PDF (QBT1811-1993)

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QB/T 1811-1993: Test Methods for Permeability to Water Vapor of Leather
QB/T 1811-1993
QB
INDUSTRIAL STANDARD OF THE
PEOPLE’S REPUBLIC OF CHINA
QB/T 1811-93
Test methods for permeability to water vapor of
leather
ISSUED ON: JULY 29, 1993
IMPLEMENTED ON: MARCH 01, 1994
Issued by: Ministry of Light Industry of PRC
Table of Contents
1 Subject content and scope of application ... 3 
2 Normative references ... 3 
3 Test principle ... 3 
4 Instruments and materials ... 3 
5 Specimens ... 4 
6 Test procedure ... 4 
7 Test results ... 5 
8 Test report ... 5 
Additional information ... 6 
Test methods for permeability to water vapor of
leather
1 Subject content and scope of application
This standard specifies the test principles, test instruments, specimen
preparation, test procedures, calculations and test reports of permeability to
water vapor of leather, under standard conditions.
This standard applies to all leathers.
2 Normative references
GB 4689.1 Leather - Laboratory sample - Location and identification
GB 4689.2 Leather - Conditioning of test pieces for physical tests
3 Test principle
Under certain temperature and humidity conditions, the leather test piece is
fixed at the mouth of the moving test bottle. The test bottle contains a solid
desiccant. When the test bottle moves, the water vapor passes through the
leather test piece AND is absorbed by the solid desiccant. Within the specified
period of time, the test bottle is weighed, to determine the weight of moisture,
which is absorbed by the desiccant, through the leather.
4 Instruments and materials
4.1 The components of the leather water vapor permeability tester shall meet
the following requirements.
a. Test bottle: As shown in Figure 1, it is equipped with a threaded cap. The
cap has a circular hole, which has a diameter of 30 mm. The circular hole
is equal to the inner diameter of the bottle bottleneck. The plane of the
bottle mouth is perpendicular to the inner wall of the bottleneck.
b. Test bottle holder: It is driven by a motor. The rotation speed is 75 ± 5 rpm.
The test bottle is placed on this circular holder. The axis of the test bottle
shall be parallel to the axis of the circle. The two axes shall be 67 mm
the specimen, with the use side facing inward, on the bottle mouth. Then fix the
test bottle on the test bottle holder. Turn on the instrument.
6.2 Use a vernier caliper to measure the inner diameter of the second test
bottle's mouth, in two mutually perpendicular directions. Mark the average value
of the diameter d, accurate to 0.1 mm.
6.3 If necessary, apply a washer or coat a layer of beeswax, between the bottle
mouth and the test piece. OR take other measures to prevent air leakage.
6.4 After the instrument has been rotated for 16 hours, shut it down. Remove
the first test bottle. Put the other half of the freshly dried silica gel (59.0 ± 0.5 g)
into the second test bottle. Remove the specimen from the first test bottle, as
soon as possible; fix it on the second test bottle, with the use side inwards.
6.5 Weigh the second test bottle. Record the weighing time. Then fix the second
test bottle on the instrument.
6.6 When the instrument rotates for 7 hours, shut it down. Remove the test
bottle. Weigh it. Record the weighing time.
7 Test results
Where:
P - Water vapor permeability, mg/ (cm2·h);
m - The increased mass of the bottle at the second weighing, mg;
d - The diameter of the bottle mouth, cm;
t - The time between two weighing, h.
8 Test report
The test report includes the following.
a. The name and source of the tested sample;
b. Each measurement result, the arithmetic average of multiple results;
c. Sample retention and test conditions;
d. Temporary factors that may have an impact on the test results.