This standard specifies the determination of volume resistivity of specially prepared samples of vulcanized rubber and thermoplastic rubber containing carbon black or ionized materials with conductive or dissipative properties in the laboratory. Adding ionized materials to rubber ingredients can also make the compound rubber have antistatic properties. This standard is applicable to materials with a resistivity lower than 10 to the power of 10 Ω·m. GB/T 2439-2001 Determination of conductive and dissipative resistivity of vulcanized rubber or thermoplastic rubber GB/T2439-2001 Standard download decompression password: www.bzxz.net

GB/T2439—2001
This standard is equivalent to ISO1853:1998 "Determination of electrical conductivity and dissipative properties of vulcanized rubber or thermoplastic rubber" and amends GB/T2439--1981 "Determination of electrical resistivity (coefficient) of conductive and antistatic rubber". The main difference between this standard and GB/T2439-1981 (1989) is that the scope of application of the standard has been expanded. According to ISO1853:1998, the thickness of the sample can be of three specifications. The distance between the current electrodes has been revised. The calculation formula is changed from two in the original standard to one. Appendix A of this standard is a prompt appendix.
This standard replaces GB/T2439~1981 (1989) from the date of implementation. This standard is proposed by the State Bureau of Petroleum and Chemical Industry. This standard is under the jurisdiction of the General Physical Test Method Sub-Technical Committee of the National Rubber Standardization Committee. The drafting unit of this standard: Shenyang Fourth Rubber Factory. The main drafters of this standard are Zhang Baojuan, Tuo Rui and Zhang Yan. This standard was first published on November 1, 1981. 159
9—2001
GB/T2439+
ISOForeword
The International Organization for Standardization (ISO) is a worldwide federation of national standards organizations (ISO member groups). The work of formulating international standards is usually carried out by ISO technical committees. All member groups interested in the project have the right to participate in the committee. Governmental or non-governmental international organizations that have relations with ISO can also participate in this work. In all aspects of electrotechnical standardization, ISO works closely with the International Electrotechnical Commission (IEC). The draft international standards adopted by the technical committees shall be sent to the member units for voting. When it is published as an international standard, at least 75% of the voting member units are required to vote in favor.
International Standard ISO1853 was formulated by ISO/TC45 Rubber and Rubber Products Technical Committee, SC2 Physical and Degradation Test Subcommittee.
This edition abolishes and replaces the first edition (ISO1853:1975), and is a technical revision of the first edition. Appendix A is for reference only.
GB/T2439--2001
ISO Introduction
Rubber is generally considered to have a high resistivity material, so rubber is widely used as an insulator. However, the addition of various substances, especially certain forms of carbon black, can significantly reduce the resistance of rubber, so that a resistivity between 10!3Q·m and 0.01Q·m can be obtained.
For many process and technical purposes, rubber with reduced resistivity is a very useful material, the most common application is to dissipate electrostatic loads. In some special environments, such as in the case of leakage of insulating materials or near electrical equipment, as a safety protection device to prevent fire or to prevent people who come into contact with it from receiving severe electric shock, the products used must have a minimum resistance limit. Rubber products that can conduct static charge and have sufficient insulation resistance to meet the above safety requirements are called dissipative rubber products, and rubber products that cannot meet safety requirements are called conductive rubber products. Since the appearance and size of the products are complex, it is impossible to determine a suitable volume resistivity (coefficient) for these two cases, but it is possible to determine a resistivity range between critical points. Conductive materials are usually considered to have a resistivity (coefficient) below 10% Qm, while dissipative materials have a resistivity (coefficient) between 105 Qm and 101 ° Qm.
In addition to static electricity, for most electrical equipment and in most buildings, the primary danger comes from the leakage current in the rated voltage power supply network. In order to prevent these dangers, it is recommended that when using a 250V AC power supply, the minimum resistance limit for dissipative rubber products should be 5×10*Q and the maximum current is 5mA. As the voltage decreases, the resistance limit can be reduced accordingly. The maximum resistance that allows static charge dissipation depends on the charge occurrence rate that can produce the minimum dangerous voltage in a specific application. The influence of temperature changes and rubber deformation on conductive and anti-static rubber. The electrical resistance of conductive and (static) rubbers is very sensitive to strain and temperature processes. The connection between them is complex and is due to the kinetic energy and structural morphology of the carbon black particles in the rubber. In general, the change in the resistance of a specimen of a given material with temperature and strain processes is very significant. For example, the resistance of a rubber just deformed at room temperature differs by a factor of one hundred or more from that of an undeformed rubber held at 100 °C for a short time.
In order to ensure a true comparison of the specimens, conditioning is specified so that the specimens reach zero deformation when the measurements are made. Electrode System
A certain type of electrode, when applied to rubber, produces a contact resistance that is thousands of times greater than the resistance of the rubber itself. Dry contacts or point contacts under light pressure give particularly poor results. Therefore, the specification of an appropriate electrode system is an important part of this test method. 161
National Standard of the People's Republic of China
Conducting and dissipative rubbers, vulcanized or thermoplastic-Measurement of resistivityGB/T 2439—2001
idt IS0 1853: 1998
Replaces GB/T2439—1981(1989）
Warning: Personnel using this standard should be familiar with regular laboratory operating procedures. This standard does not purport to cover all safety issues that may arise from its use. It is the user's responsibility to establish appropriate safety and health systems and ensure compliance with national regulations. 1 Scope
This standard specifies the laboratory determination of the volume resistivity of specially prepared specimens of conductive or dissipative vulcanized rubber and thermoplastic rubber containing carbon black or ionizing substances. Adding ionizing substances to rubber ingredients can also make the mixed rubber have antistatic properties.
This standard applies to substances with a resistivity lower than 101α·m. 2 Referenced standards
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, and parties using this standard should explore the possibility of using the latest versions of the following standards. GB/T2941-1991 Standard temperature, humidity and time for environmental conditioning and testing of rubber specimens (eqvISO471:1983) 3 Test device
The test circuit diagram is shown in Figure 1.
3.1 Power supply
The power supply adopts a DC power supply with a minimum resistance to ground of 101°Q2 and a power consumption of no more than 1W in the specimen. 3.2 Measuring current meter bzxZ.net
The indication error of the measuring current meter shall not exceed ±5%. Note: Using an electrometer (3.5), very small currents can be calculated from the measurement of the voltage drop across a known resistor. Approved by the General Administration of Quality Supervision, Inspection and Quarantine of the People's Republic of China on 2001-08-28 162
Implementation on 2002-05-01
GB/T2439-2001
1-Test piece: 2-Current electrode: 3-Insulating pad: Resistance at least 1012Ω; 4-Potentiometer (electrometer): 5-Voltage electrode: 6-Adjustable DC voltage Figure 1 Test circuit diagram
3.3 Sample fixture and current electrode
The sample fixture consists of a polystyrene plate about 10 mm thick for mounting the measuring electrode (see Figure 1). The current electrode should be clean metal about 5 mm long and connected to the entire width of the sample with suitable wiring clips or clamping devices. The distance between the current electrodes should be 50 mm ± 1 mm or 100 mm ± 1 mm, and the resistance between them should be greater than 1012α. 3.4 Composition of voltage electrodes
A contact pressure of about 0.65 N can be applied on a 10 mm wide specimen or a contact pressure of about 1.3 N can be applied on a 20 mm wide specimen (see Figure 2). The resistance between the voltage electrodes should be greater than 10120. 50
1-Polystyrene; 2-Stainless steel; 3-Specimen width at least 10 mm; 4-(10 mm ~ 20 mm) ± 2% Figure 2 Voltage electrodes
3.5 Electrometer
Has an input resistance greater than 100. Reference materials for this instrument are given in Appendix A (Suggestive Appendix). 3.6 Insulating plate
The resistivity of the insulating plate is greater than 103α·m. 3.7 Constant temperature box
The constant temperature box can control the temperature at 70℃ ± 1℃. 163
4Sample
GB/T24392001
4.1 The sample is a strip of vulcanized rubber or thermoplastic rubber, with a width of 10mm±0.5mm or 20mm±0.5mm, a minimum length of 70mm, a thickness of 2mm, 4mm or 6.3mm, and a thickness tolerance of ±5%. 4.2 The sample can be cut with a blade or a die, but care must be taken to minimize deformation as much as possible, because deformation will affect the resistance value. 4.3 The surface of the sample must be clean, smooth, free of defects such as cracks, bubbles and impurities, and the surface is not allowed to be polished or ground. 4.4 The same size of sample should be used for comparative tests. 5 The number of samples
is three samples of the same specification.
6 Procedure
6.1 According to GB/T2941, the sample after vulcanization or molding should be parked for no less than 16 hours, and then the sample is placed on the fixture, and the current electrodes are clamped at both ends of the sample, and placed in a constant temperature box at 70℃±1℃ for 2 hours. 6.2 Take the fixture with the sample out of the constant temperature box and adjust it at the standard laboratory temperature and humidity for no less than 16 hours according to GB/T2941. Do not move the sample.
6.3 Place the voltage electrode on the sample, keep the distance between the two voltage electrodes at 10mm~20mm, and ensure that the blade is at right angles to the current direction. The distance between any one edge of the voltage electrode and the current electrode is not less than 20mm. Measure the distance between the two edges of the voltage electrode, and the measurement error is no more than ±2%. After 1 minute of power on, use an electrometer to measure the stable voltage between the two edges of the voltage electrode. 6.4 Repeat step 6.3 twice on the same sample. Move the voltage electrode once for each measurement. To determine the voltage distribution over the entire length of the sample.
6.5 Test the other two samples in the same way. Test results
Take the arithmetic mean of the three resistance test values ​​of each sample, and calculate the resistivity β according to formula (1), unit: 2·m. o
Where: V-—
measurement voltage, V:
sample width, m;
t--sample thickness, m;
p-—distance between voltage electrodes, m:
I-measurement current, A.
Take the median of the resistivity of three samples to represent the test result. 8 Test report
The test report must include the following:
a) The standard on which the test is based;
b) Detailed description of the sample:
1) Detailed description of the sample and its source;
2) If known, it should include the mixing components and processing conditions;3) The size of the sample;
c) Detailed description of the test:
1) Temperature and viscosity conditions during the test;164
·（ 1)
2) Voltage supplied to the current electrode;
3) Current passing through the sample;
d) Test results:
GB/T 2439-
—2001
1) Express the test results as the median of the resistivity of the three samples; 2) If required, include the arithmetic mean of the individual resistivity of each sample; e) Test date;
f) Tester;
g) Auditor.
GB/T 2439--2001
Appendix A
(Indicative Appendix)
Solid-state electrometer
Within the scope of application of this International Standard, the voltage and current measurements may also be made using a solid-state electrometer with a sufficiently high input resistance.
The Model 602 solid-state electrometer has an input resistance greater than 1014Ω and a range of 0.001V to 10V full scale when used as a voltmeter; when used as an ammeter, its range is 10-14A to 0.3A full scale. 166
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