Codeofchina.com is in charge of this English translation. In case of any doubt about the English translation, the Chinese original shall be considered authoritative.
Test method for thermal conductivity of plastics by means of the guarded hot plate
This standard is applicable to measurement of thermal conductivity of plastics by means of guarded hot plate (steady-state method), and is not applicable to measurement of plastics with a thermal conductivity greater than 2.20W/(m·K).
1 Definitions
1.1
thermal flux Φ
heat passing through a certain surface per unit time, in W
1.2
thermal flux density q
heat passing through unit area of a certain surface per unit time, in W/m2
1.3
thermal conductivity λ
heat passing through unit area per unit temperature gradient perpendicular to unit area under stable conditions, in W/(m·K)
2 Principle
2.1 This method is based on the principle of unidirectional steady heat conduction. Measure the heat passing through the effective heat transfer area of the test specimen, the temperature difference between the upper and lower surfaces of the test specimen, as well as the thicknesses of them when they are exposed to different stable temperatures, and then calculate the thermal conductivity accordingly.
3 Test specimen
3.1 The test specimen shall be homogeneous hard material, and the two surfaces of it shall be flat, smooth and parallel with each other and free of defects such as cracks. For flat test specimens, the unevenness shall be within 0.5mm/m.
In case of soft materials or granules, a wooden frame is necessary, and the test specimen shall be homogeneous in general.
3.2 The test specimen shall be a representative part of the product and shall be taken directly from the product or prepared in accordance with the product standard.
3.2.1 In case of testing a specimen with a double-plate thermal conductivity meter, the same specimen shall be selected where possible.
3.3 The test specimen shall be round or square, and its diameter or side length shall be equal to that of the guarded hot plate, and its thickness shall not be less than 5 mm. The maximum thickness of it shall be determined according to the meter but shall not exceed 1/8 of its diameter or side length.
3.4 Before testing, the test specimen shall be conditioned according to the requirements of the product standard. If no product standard is available, the test specimen shall be treated for 24 h under the conditions specified in GB 2918-82 Plastics - Standard atmospheres for conditioning and testing.
3.5 The number of test specimen of each group shall not be less than 2.
4 Test conditions
4.1 Test environment: the test shall be conducted under the normal temperature and humidity specified in GB 2918-82.
4.2 Test conditions
Temperature of hot plate: below 333 K.
Temperature of cold plate: room temperature or required temperature.
The temperature difference between the cold plate and the hot plate shall not be less than 10 K, and the temperature gradient through the test specimen shall be between 400 K/m and 2,000 K/m.
Note: If no dew prevention measure is available, the temperature of the cold plate shall be at least 5 K higher than the dew-point temperature of the environment.
5 Test apparatus
For the purpose of this method, the apparatus required shall be a plane table thermo-conductivity meter with a guarded hot plate. It consists of a heating plate (including a main heating plate and a protective heating plate), a cold plate, a temperature measuring instrument and a calorimeter.
5.1 Heating plate: the diameter of the main heating plate shall be at least 100mm, and the minimum width of the protective heating plate shall be at least 1/4 of the side length or diameter of the heating plate. A gap of appropriate dimension shall be reserved between the main heating plate and the protective heating plate, and the flat area of the gap shall not be 8% greater than the area of the main heating plate. The heating plate shall be flat and smooth. And its surface unevenness shall be within 0.25mm/m. The temperature of it shall be uniform, and the temperature fluctuation of the main heating plate shall not be greater than 2% of the temperature difference between the two sides of the test specimen, and 5% for the protective heating plate. There shall be an average temperature balance detector between the main and protective heating plates.
5.2 Cold plate: it shall have the same dimension as the heating plate and subject to the same requirements for unevenness.
5.3 The hot plate and cold plate shall have a radiation coefficient greater than 0.8.
5.4 Temperature measuring instrument: measure the temperature on both surfaces of the test specimen with a thermocouple with a thermocouple wire diameter less than 0.2mm, accurate to not less than 0.1 K.
5.5 Calorimeter: measure the heat passing through the test specimen, accurate to 1%.
5.6 Heating power: the fluctuation of the heating voltage shall not exceed ± 0.5%.
1 Definitions 2 Principle 3 Test specimen 4 Test conditions 5 Test apparatus 6 Test procedure 7 Test result 8 Test report Additional explanation:
Codeofchina.com is in charge of this English translation. In case of any doubt about the English translation, the Chinese original shall be considered authoritative.
Test method for thermal conductivity of plastics by means of the guarded hot plate
This standard is applicable to measurement of thermal conductivity of plastics by means of guarded hot plate (steady-state method), and is not applicable to measurement of plastics with a thermal conductivity greater than 2.20W/(m·K).
1 Definitions
1.1
thermal flux Φ
heat passing through a certain surface per unit time, in W
1.2
thermal flux density q
heat passing through unit area of a certain surface per unit time, in W/m2
1.3
thermal conductivity λ
heat passing through unit area per unit temperature gradient perpendicular to unit area under stable conditions, in W/(m·K)
2 Principle
2.1 This method is based on the principle of unidirectional steady heat conduction. Measure the heat passing through the effective heat transfer area of the test specimen, the temperature difference between the upper and lower surfaces of the test specimen, as well as the thicknesses of them when they are exposed to different stable temperatures, and then calculate the thermal conductivity accordingly.
3 Test specimen
3.1 The test specimen shall be homogeneous hard material, and the two surfaces of it shall be flat, smooth and parallel with each other and free of defects such as cracks. For flat test specimens, the unevenness shall be within 0.5mm/m.
In case of soft materials or granules, a wooden frame is necessary, and the test specimen shall be homogeneous in general.
3.2 The test specimen shall be a representative part of the product and shall be taken directly from the product or prepared in accordance with the product standard.
3.2.1 In case of testing a specimen with a double-plate thermal conductivity meter, the same specimen shall be selected where possible.
3.3 The test specimen shall be round or square, and its diameter or side length shall be equal to that of the guarded hot plate, and its thickness shall not be less than 5 mm. The maximum thickness of it shall be determined according to the meter but shall not exceed 1/8 of its diameter or side length.
3.4 Before testing, the test specimen shall be conditioned according to the requirements of the product standard. If no product standard is available, the test specimen shall be treated for 24 h under the conditions specified in GB 2918-82 Plastics - Standard atmospheres for conditioning and testing.
3.5 The number of test specimen of each group shall not be less than 2.
4 Test conditions
4.1 Test environment: the test shall be conducted under the normal temperature and humidity specified in GB 2918-82.
4.2 Test conditions
Temperature of hot plate: below 333 K.
Temperature of cold plate: room temperature or required temperature.
The temperature difference between the cold plate and the hot plate shall not be less than 10 K, and the temperature gradient through the test specimen shall be between 400 K/m and 2,000 K/m.
Note: If no dew prevention measure is available, the temperature of the cold plate shall be at least 5 K higher than the dew-point temperature of the environment.
5 Test apparatus
For the purpose of this method, the apparatus required shall be a plane table thermo-conductivity meter with a guarded hot plate. It consists of a heating plate (including a main heating plate and a protective heating plate), a cold plate, a temperature measuring instrument and a calorimeter.
5.1 Heating plate: the diameter of the main heating plate shall be at least 100mm, and the minimum width of the protective heating plate shall be at least 1/4 of the side length or diameter of the heating plate. A gap of appropriate dimension shall be reserved between the main heating plate and the protective heating plate, and the flat area of the gap shall not be 8% greater than the area of the main heating plate. The heating plate shall be flat and smooth. And its surface unevenness shall be within 0.25mm/m. The temperature of it shall be uniform, and the temperature fluctuation of the main heating plate shall not be greater than 2% of the temperature difference between the two sides of the test specimen, and 5% for the protective heating plate. There shall be an average temperature balance detector between the main and protective heating plates.
5.2 Cold plate: it shall have the same dimension as the heating plate and subject to the same requirements for unevenness.
5.3 The hot plate and cold plate shall have a radiation coefficient greater than 0.8.
5.4 Temperature measuring instrument: measure the temperature on both surfaces of the test specimen with a thermocouple with a thermocouple wire diameter less than 0.2mm, accurate to not less than 0.1 K.
5.5 Calorimeter: measure the heat passing through the test specimen, accurate to 1%.
5.6 Heating power: the fluctuation of the heating voltage shall not exceed ± 0.5%.
Contents of GB 3399-1982
1 Definitions
2 Principle
3 Test specimen
4 Test conditions
5 Test apparatus
6 Test procedure
7 Test result
8 Test report
Additional explanation:
