GB T 6342-1996 is the Chinese national standard for the determination of linear dimensions and apparent density of foam plastics and rubber. Apparent density refers to the ratio of mass to volume of a material under certain conditions, and is an important parameter to measure the properties of foam and rubber materials. The following is an introduction to the apparent density test in the GB T 6342-1996 standard, including the scope of application of the standard, test methods, instruments and equipment, etc.
1.Scope of application of the standard.
The apparent density test standard of GB T 6342-1996 is applicable to foam and rubber products, including foam plastics, rubber sheets, tubes, fittings, etc. of various shapes and uses. This standard specifies the method and requirements for the determination of apparent density to ensure that the density of the product meets the requirements of design and manufacturing.
2.Test Method:
The method of determining apparent density mainly includes the measurement of the mass and volume of the material, and the apparent density is obtained by dividing the mass by the volume. The specific test method is as follows:
Quality determination: The quality of the material is determined by the balance precision instrument. In the test, attention should be paid to eliminating the influence of external factors on the quality determination to ensure accuracy.
Volume determination: Volume determination can be performed by several methods, such as water exclusion method, direct measurement method, etc. Among them, the water exclusion method is a commonly used method to measure the volume of foam and rubber products. By immersing the sample in water, the amount of water excluded is determined, and the volume of the sample is obtained.
Calculation of apparent density: The apparent density can be obtained by substituting the measured mass and volume into the calculation formula. The calculation process should comply with the standard regulations to ensure accuracy and reliability.
3.Instruments and equipment.
When performing apparent density determination, some instrumentation is required to ensure the accuracy and repeatability of the measurement. The main instruments and equipment include:
Balances: Used to accurately measure the mass of materials.
Volumetric bottles or sinks: for volumetric determination, depending on the specific needs, different volumetric methods can be selected.
Temperature control equipment: The determination of apparent density usually requires a certain temperature, so corresponding temperature control equipment is required.
4.Precautions for measurements.
When performing apparent density determination, the following aspects need to be noted:
Standard conditions: The measurement should be carried out in accordance with the conditions specified in the standard, including the control of environmental conditions such as temperature and humidity.
Sample handling: Samples need to be treated according to the methods specified in the standard, such as removing surface moisture, before proceeding to the measurement.
Accuracy of volume determination: Volume determination is a key part of apparent density determination, and it is necessary to ensure the accuracy of measurement. When using the water exclusion method, it is important to ensure that the sample is completely immersed in water to exclude the influence of factors such as air bubbles on the measurement.
Data processing: When calculating the apparent density, it is necessary to strictly follow the calculation formula specified in the standard to ensure the accuracy of the results.
By following the apparent density determination methods and requirements specified in the GB T 6342-1996 standard, the apparent density determination of foam plastic and rubber products can be ensured to achieve a certain accuracy and reliability, which provides an effective means for the control of product quality.