Original standard number GB 9892-88 HG/T 2874-1997 Determination of thermal shrinkage of microporous materials for footwear HG/T2874-1997 Standard download decompression password: www.bzxz.net

HG/T 2874—1997
This standard is a revision of the original GB/T9892--88 standard. This standard is equivalent to the British standard BS5131:2.10:80 "Test methods for footwear and footwear materials-Part 2: Heat shrinkage of microporous materials"
From the date of implementation of this standard, the original GB/T 9892-88 has been amended. This standard is proposed by the Technical Supervision Department of the Ministry of Chemical Industry of the People's Republic of China, and is under the jurisdiction of Shanghai Rubber Shoes Research Institute. This standard is drafted by Shanghai Rubber Shoes Research Institute. The main drafters of this standard are Shi Qiong, Xie Beiqian, and Xu Chun. ICS61.060
Registration No. 4461997
Chemical Industry Standard of the People's Republic of China
Determination of the heat shrinkageof celluar materlal for footwear
shoes1 Scope
This standard specifies the principle and test method of thermal shrinkage of microporous materials for shoes. This standard is applicable to the determination of linear shrinkage of microporous material samples for shoes after heating.2 Referenced standards
HG/T 2874-1997
The provisions contained in the following standards constitute the provisions of this standard through reference in this standard. When this standard is published, the versions shown are valid. All standards will be revised. Parties using this standard should explore the possibility of using the latest versions of the following standards, GB 2941-91 Standard temperature, humidity and time for environmental conditioning and testing of rubber specimens. (cqvISO471:1983, IS0 1826:1981)
HG/T2198--91 General requirements for physical test methods for vulcanized rubber 3 Definitions
This standard adopts the following definitions,
Shrinkage rate: the percentage of shrinkage of a sample after it is heated at a specified temperature and at a constant temperature for a certain period of time under normal pressure, 4 Principle
When the microporous material for shoes is heated, the expansion of the gas in the micropores can lead to the internal contraction force of the bubble wall to maintain the balance of the action force and the reaction force. When the bubble ruptures or the gas escapes, the material shrinks. Place the sample in hot air of a specified overflow under normal pressure and heat it. Measure the distances between corresponding reference points on the sample before and after heating, and express its shrinkage as the percentage of the difference between the two points and the original distance.
5 Testing equipment
5.1 Hot air thermostatic box: Heat the sample and maintain the temperature of the test area within the range of (70±1)°C and (100±1)°C.
5.2 Sharp knife: used to cut two reference cuts on the sample with a spacing of 100 mm or 50 mm. Vernier caliper: with an accuracy of 0.02 mm, used to measure the spacing between the two cuts on the sample. 5.3
Instructions for use:
11 British Standard BS 5131: 2.10: 80 with an accuracy of 0.2 mm, approved by the Ministry of Chemical Industry of the People's Republic of China on April 21, 1997 and implemented on October 1, 1997
6 Preparation of test specimens
HG/T 2874 -1997
6.1 Cut three specimens of 150mm±2.5mm or 75mm±1.5mm in length, 25mm±1.0mm in width, and 5mm±0.5mm in thickness from the test material along the longitudinal and transverse directions of the sole, see Figure 1. The bottom material specimen should be cut from the ground.
One side of the specimen
Incision position
Measuring point
One side of the specimen
Incision position
Note: The dimensions without allowable difference are the approximate values. Figure 1 Long and short specimens for measuring heat shrinkage and their reference incision positions 6.2 The grinding of the specimen shall be carried out in accordance with the provisions of HG/T2198. The surface of the specimen after grinding shall not have patterns or dense skin and shall be flat. The parking of the specimen after grinding shall be carried out in accordance with the provisions of GB2941. The test strip
According to the material of the specimen or actual needs. It can be selected from the two conditions of 70℃ ×24 h and 100℃ ×1 h. Test steps
81 Sample marking and measuring plate
As shown in Figure 1, first cut a notch on both sides of the sample with a depth not exceeding 0.5mm and spanning its entire width. The distance between the two notches of the long sample is 100 mm±1.5mm, and the distance between the notches of the short sample is 50 mm±1.5mm. Measure the distance between the two notches along the center line of the sample. To facilitate the measurement, the position of the measuring point can be marked with a suitable marking pen. 8.2 Heating treatment
Adjust the constant temperature box to the required overflow. After stabilization, place the sample horizontally in the constant temperature box for heating. 83 Measurement after heating
After heating, take out the sample and let it stand at room temperature of (23±2)2 for 30 minutes, and then measure the distance between the two cuts again.
9 Test results
9.1 The thermal shrinkage rate of the sample is calculated according to the following formula: s(%) -
Where: S—thermal shrinkage rate, %;
a. a,
The distance between the two cuts before heating,;
The distance between the full cuts after heating, m,
9.2 Test results Take the arithmetic mean of the heat shrinkage of the three specimens according to the direction. Test report
The test report should include the following contents:
Sample name and material;
Cutting direction and size of the specimen;
Test conditions:www.bzxz.net
Test basis:
Test results;
Test date;
Tester, reviewer.
Adoption instructions:
2) British Standard BS5131:2.10:80 Place at room temperature (20±2)C. 25
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