HG/T 3087-2001 Rapid determination method for storage period of static sealing rubber parts
Some standard content:
Record number: 10140-2002
HG/T3087-2001
This standard is revised from the recommended chemical industry standard HG/T3087-1986 (1997) "Quick Determination Method for Storage Period of Static Sealing Rubber Parts" with reference to the former Soviet Union national standard I()CT9.035--74 "Rapid Determination Method for Storage Period of Fixed Connection Sealing Parts".
The main technical differences between this standard and HG/T3087-1986 (1997): - Added the content of Chapter 2.
Supplementary provisions are made on the scope||t t||Appendix A and Appendix B of this standard are standard appendices, and Appendix C is a suggested appendix. The original HG/T3087-1986 will be abolished from the date of implementation of this standard. This standard is proposed by the policies and regulations of the former State Bureau of Petroleum and Chemical Industry. This standard is under the jurisdiction of the National Technical Committee for Rubber and Rubber Products Standardization, Sealing Products Sub-Technical Committee. The responsible drafting unit of this standard is the Northwest Rubber and Plastic Research and Design Institute, and the main drafters of this standard are Li Yongjin and Huang Zuchang. This standard was first issued as the national standard GB70411986 in 1986. In 1997, it was adjusted to a recommended chemical industry standard and renumbered as HG/T 3087-1986 (1997). 1 Scope
Chemical Industry Standard of the People's Republic of China
Storage period of static sealing rubber partsWww.bzxZ.net
Quick determination method
Mcthnd of accelerated determination forSelf-life of rubber static sealing partsHG/T3087—2001
代翘IIG/T31871986(1997)
This standard is applicable to the determination of the storage period of static sealing rubber parts in the state of non-deformation and deformation (radial compression 12%~25%, axial compression 15%~10%), in air and various oil media, under warehouse storage conditions to maintain the working ability. This method is not suitable for rubbers that are easily hydrolyzed, such as silicone rubber, polyurethane, acrylate and epichlorohydrin rubber, etc., when the parts are in contact with air during storage.
The rubber parts measured according to this method can maintain the working ability of the parts under the condition of non-deformation and deformation (radial compression 12%~25%, axial compression 15%~10%) in air and various oil media. The storage period of the parts can be used as one of the bases for formulating the storage period of the product. 2 Cited standards
The provisions contained in the following standards constitute the provisions of this standard through reference in this standard. When this standard was published, the versions shown were valid. All standards will be revised, and parties using this standard should explore the possibility of using the latest versions of the following standards. G13/T528—1998 Determination of tensile stress-strain properties of vulcanized rubber or thermoplastic rubber (eqVISO37:1994) Determination of compressive stress relaxation of vulcanized rubber at room temperature and high temperature (neuISO3384:1979) GB/T 1685--1989
GB/T3512-1989 Rubber hot air aging test method (ncqIS () 188: 1985) GB/T7759: 1996 Determination of compression set of vulcanized rubber or thermoplastic rubber at room temperature, high temperature and low temperature (cqVISO815: 19912
3 Principle of the method
For rubber sealing parts under warehouse purchase and storage conditions, the main factors causing performance changes are heat, oxygen, mechanical stress and oil medium. Within a certain temperature range, the oven accelerated aging is the same as the deterioration mechanism under warehouse storage conditions. Using the high-temperature oven accelerated test data, the storage period at warehouse temperature can be extrapolated. For the undeformed rubber parts, the aging characteristic index can be used as the tensile elongation at break, and for the deformed rubber parts, the accumulated compression set or compression stress relaxation can be used.
4 Test specimens
4.1 The test specimens for measuring the tensile elongation at break shall comply with the requirements for test specimens in (GJ3/T528. 4.2 The test specimens for measuring the shrinkage permanent deformation and shrinkage stress relaxation shall comply with the requirements for test specimens in GB/T7759 and GB/T1685. 5 Testing instruments
5.1 Oven
The oven shall comply with the provisions of GB/T 3512. Approved by the State Economic and Trade Commission on January 24, 2002 and implemented on July 1, 2002
5.2 Tensile testing machine
HG/T 3087—2001
Tensile testing machine shall comply with the relevant provisions of GB/T528. 5.3 Compression stress relaxation instrument
Compression stress relaxation instrument shall comply with the relevant provisions of G1B/T1685. 6 Test
6.1 Test conditions
6. t. 1 Test temperature
6.1.1.1 The aging test temperature shall be five, at least four, and the interval between adjacent temperatures shall not be less than 10K. 6.1.1.2 The upper limit of the test temperature varies with the raw rubber and the vulcanization system. Generally, the following data shall be referred to: 363K for natural and chloroprene rubber; 383~363K for nitrile, benzene, butyl and butadiene rubber; 403~383K for EPDM. 6.1.1.3 In order to properly select the upper limit of the test temperature, necessary exploratory tests shall be carried out. 6.1.2 Test interval
6.1.2.1 The termination time of the test varies with the temperature. For the tests at the three higher temperatures among the five temperatures, the performance change must reach the critical value before the test can be terminated; at the end of the test at the lowest temperature, the compression set shall not be less than 50%, and the stress relaxation and elongation shall not be higher than 50% of the initial value.
6.1.2.2 The test data at each test temperature shall not be less than 10. The time interval of each test point can be determined according to the performance change. Generally, the interval in the early stage is short and the interval in the later stage is long. 6.1.2.3 The performance change of the first test point at each test temperature is The compression permanent deformation shall not be higher than 20%, and the stress relaxation shall not be lower than 80% of the initial value. The elongation shall not be lower than 90% of the initial value. 6.1.3 Test in oil medium
When shrink-sealed parts are stored in oil medium, the specimens shall be subjected to aging tests in oil medium. During the test, the aging fixture is placed in a sealed container filled with test oil: the volume of this container is 150mmX100mm×80mm, and the amount of test oil should make the fixture completely immersed in the oil. The container is placed in an oven for aging, and the fixture is removed after the specified time interval. Take it out of the container. Use filter paper to absorb the oil on the surface of the test piece and carry out relevant tests. After the test is completed, put it back into the container for aging. 6.2 Test steps
6.2.1 Carry out accelerated aging test in oven according to GB/T35126.2.2 Compression stress relaxation determination is carried out according to GB/T1685. Only the initial stress before aging is after the fixture is put on: the stress is measured after parking for 3 days in the standard laboratory environment. For the test in oil medium, the fixture is placed in a closed container filled with oil and the stress is measured after parking for 3 days in the standard laboratory environment. The stress after aging is measured after the fixture is taken out of the aging box and parked for 3 hours in the standard laboratory environment. After each measurement, put the fixture into the aging box for the next week of aging. 6.2.3 Compression permanent deformation determination is carried out according to GB/T7759. The initial height of the sample is the height of the clamp after it is placed in the standard test environment for 1 day, then the load is removed, and the height is measured after it is placed for 1 day. For the test in oil medium, the clamp is placed in a closed container containing oil, placed for 1 day in a standard test room environment, then the clamp is taken out of the clamp and the load is removed, and the height is measured after it is placed for 1 day as the initial height. The height of the sample after aging is the height of the clamp after it is taken out of the oven and the load is removed, and the height is measured after it is placed for 1 day in a standard test room environment. After each measurement, the sample is put back into the clamp and sent back to the aging box for the next cycle of aging. 6.2.4 The elongation at break is determined in accordance with GB/T528. The elongation at break before aging is the average value of 10 measurements, and the elongation at break after aging is the average value of five measurements. 7 Result processing
7.1 The relationship between the aging characteristic index and the aging time can be described by the following empirical formula: y= Be-kr\
Wherein: 3--For stress relaxation, the ratio of the stress at any aging time to the initial stress f before aging. For the tensile elongation K
HG/T3087-2001
Rate is the ratio of the elongation L at any aging time to the elongation 1 before aging. For the compression water permanent deformation, it is 1 minus the compression permanent deformation rate E at any aging time; test constant;
Rate constant, d 1
Aging time, d;
Empirical constant.
7.2 The relationship between the rate constant K and the aging temperature T obeys the Arrhenius formula: K=Ac
Wherein: E
Surface activation energy, 1·mol-l;
Gas constant,J·K-1·mol--
Aging temperature.K;
Frequency quadratic, d,
7.3 Estimation of formula parameters
7.3.1 Estimation of parameters using successive approximation method
After logarithmic transformation, the white variable contains the parameter to be estimated Q, which can be solved by the method of successive approximation. The criterion of approximation is to minimize [(
when the estimate is accurate to two decimal places.
In the formula, for the test value of the characteristic index of the th test point at the th aging temperature, the test value of the th test point at the 1st aging temperature, the test value of the th test point at the 2nd aging temperature. Predicted values of pilot characteristic indicators. 7.3.2 Calculation of near-criterion 1
When α is a certain trial value, equation (1) can be transformed into the following first-line form after logarithmic transformation: Y=a+$x
Where:
Y=IgyalgB,b=-
Estimate α and b by the least squares method.
The velocity constant K at p test temperatures can be obtained from this; equation (2) can be transformed into the following form after logarithmic transformation:Where:
-2.303h, and B,=10 boxes, then the estimated value of parameter 3 in equation (1) B=ER
W=lg K,C--lg A,
Estimate C and D by the least multiplication method.
2w·Ez
HG/T 3087 ---2001
From this, the estimated value of the rate constant K at β test temperatures can be obtained: K,=10
Tip: This standard content only shows part of the intercepted content of the complete standard. If you need the complete standard, please go to the top to download the complete standard document for free.