This standard specifies the method for determining the ring compression strength of paper and paperboard using a compression tester. This standard is applicable to paper and paperboard with a thickness of 0.28~0.51mm for making cartons and boxes. It can also be used for paper and paperboard with a thickness as low as 0.15mm and as high as 1.00mm, but the reliability of the edge compression strength of the sample is poor. GB/T 2679.8-1995 Determination of the ring compression strength of paper and paperboard GB/T2679.8-1995 Standard download decompression password: www.bzxz.net

National Standard of the People's Republic of China
Determination of compressive strength of paper and board
Paper and board-Determination of compressive strength--Ring crush method
This standard is equivalent to the international standard ISO/DIS12192 "Paper and board--Compressive strength
1 Subject content and scope of application
This standard specifies the method for determining the ring crush strength of paper and board using a compression tester. GB/T 2679.8--1995
Replaces GB2679.8---81
-Ring crush method".
This standard is applicable to paper and board with a thickness of 0.28~~0.51mm for making cartons and paper boxes, and can also be used for paper and board with a thickness as low as 0.15mm and as high as 1.00mm, but the reliability of the edge crush strength of the sample is poor. 2 Reference standards
GB/T450—89 Paper and paperboard sample collection GB/T451.2--89 Paper and paperboard quantitative determination method GB/T451.389 Paper and paperboard thickness determination method GB/T10739—89 Standard atmosphere for handling and testing of pulp, paper and paperboard samples 3 Terms
3.1 Ring compression strength
The maximum compressive force that the edge of the ring sample can withstand when it is compressed until it collapses, expressed in kN/m. 3.2 Ring compression strength index
The average ring compression strength divided by the quantitative is the ring compression strength index, expressed in N·m/g. 4 Instruments
4.1 Sample cutting punch
Special punch that can punch and cut to the size accuracy required by this standard. 4.2 Sample seat
Inner diameter 49.30±0.05mm, groove depth 6.35±0.25mm. The deviation of the parallelism between the bottom of the circular groove and the bottom of the specimen holder is no more than 0.01mm. The groove wall and the groove bottom are at right angles, and there should be no chamfers or rounded corners at the angle. For this reason, it is best to process the groove bottom and the groove wall in two parts and then assemble them into one piece. The groove wall is processed with a specimen insertion gap with a width of no more than 1.25mm in the tangential direction. The specimen holder is equipped with inner plates of different diameters, so that the specimen gap generated by the specimen holder inserted into the inner plate can adapt to specimens of different thicknesses (see Table 1). Table 1
Thickness of specimen
0.150~~0.170
0.171~0.200
Approved by the State Administration of Technical Supervision on July 6, 1995 568
Diameter of inner disk
48.80±0.05
48.70±0.05
Implemented on April 1, 1996
4.3 Compression instrument
Thickness of specimen
0. 201~0. 230
0.231~0. 280
0.281~0. 320
0. 321~~0. 370
0. 371~~ 0. 420
0. 421~~0. 490
0. 491~~0. 570
0. 571~0.670
0. 671~0. 770
0. 771~~ 0. 900
0. 901~~1. 000
4.3.1 Fixed platen electronic compressor
GB/T 2679.81995
Continued Table 1
Diameter of inner disk
48.60±0.05
48.50±0.05
48.30±0.05
48.20±0.05
48.00±0.05
47.80±0. 05
47.60±0.05
47.30±0.05
47.00±0.05
46.60±0.05
46.20±0.05
The instrument is equipped with two upper and lower pressure plates with a size of not less than 100mm×100mm. The plate surface is straight and meets the following requirements: a. The parallelism deviation between the two plates is not greater than 1:2000; b. The lateral shaking of the two plates does not exceed 0.05mm. mmbZxz.net
During the test, one pressure plate is driven by a motor to press against the other pressure plate, and the pressure plate runs at a speed of 12.5±2.5mm/min. The force measurement accuracy of the instrument is 1% of the indicated value.
4.3.2 Bending beam compression instrument
The requirements for the upper and lower pressure plates are the same as those for the fixed plate electronic compression instrument. During the test, the speed of the upper plate pressing the lower plate is 12.5±2.5mm/min, the loading speed is 110±23N/s, and the applicable range of the instrument is 20% to 80% of the maximum range of the spring plate. The force measurement accuracy of the instrument is 1% of the indicated value.
The use of this type of instrument for testing should be indicated in the report and shall not be used for arbitration testing. 4.4 Fine wire gloves
5 Sampling and processing
5.1 Sampling is carried out in accordance with the provisions of GB/T450, and the samples are processed in accordance with the provisions of GB/T10739 and tested under such conditions. 5.2 From the treated paper sample, a sample with a length of 152.0±0.2mm and a width of 12.70±0.1mm is strictly cut longitudinally. At least 10 slices are cut longitudinally and transversely, and the edges of the slices are not allowed to have burrs or other defects that affect the measurement results. The specimen with the long side perpendicular to the longitudinal direction is used to measure the longitudinal ring compression strength, and the specimen with the long side parallel to the longitudinal direction is used to measure the transverse ring compression strength. The parallelism error of the two long sides of the specimen shall not exceed 0.015 mm.
6 Test steps
6.1 The specimen shall be touched with gloved hands during the test. First, measure the specimen thickness and select the inner plate of the specimen holder according to the specimen thickness. Carefully insert the specimen into the specimen holder and make sure it is inserted to the bottom. 6.2 Place the specimen holder in the middle of the lower pressure plate with the specimen ring opening facing the operator. Then start the instrument and press the specimen until it collapses. The fixed plate electronic instrument directly reads the pressure value with an accuracy of 1N, and the bending beam instrument reads the maximum deformation of the spring plate with an accuracy of 0.01mm. Then find the force required to collapse the specimen from the stress-strain curve of the spring plate with an accuracy of 1N. 569
GB/T 2679.8—1995
6.3 Repeat the test for at least 10 specimens in each direction, and bend 5 specimens in each direction with the front side facing outward and the back side facing outward into a ring for testing.
7 Calculation of results
7.1 Calculate the average value of the longitudinal and lateral forces F (N) respectively. 7.2 Ring compression strength
Calculate the ring compression strength according to formula (1):
Where: R-ring compression strength, kN/m;
Force value read when the specimen is crushed, N;
152----Length of specimen, mm.
Report the average ring compression strength R, accurate to 0.01 kN/m. 7.3 Ring compression strength index
If necessary, the ring compression strength index can be calculated according to formula (2), accurate to o.1 N·m/g. Ra
W——quantitative, g/m2.
8Precision
Precision of test results (see Table 2).
Average value of 10 samples
Average value of 20 samples
9Test report
The test report shall include the following contents:
This national standard number;
The temperature and humidity treatment conditions used;
The mark and description of the test sample;
The type of instrument used;
Repeatability
Report the ring crush strength, ring crush strength index and coefficient of variation as needed; Any deviation from this standard or possible influencing factors. Reproducibility
: (2)
A1 Calibration of platen parallelism
GB/T 2679.8--1995
Appendix A
Instrument calibration
(Supplement)
Use an internal diameter micrometer to measure the distance between the four corners of the upper and lower pressure plates. The difference between the maximum and minimum divided by the side length of the pressure plate is the parallelism deviation between the two plates, which should not be greater than 1:2000.
A2 Calibration of the accuracy of the compression instrument
Measure on the instrument with an electronic pressure calibrator with an accuracy of one thousandth. Place the sensor (with seat) of the pressure calibrator in the middle of the upper and lower pressure plates of the compression instrument, drive the pressure plate to directly apply pressure to the sensor, observe the pressure calibrator head, and stop applying pressure when the predetermined value is reached. Read the indicated values ​​of the compression instrument and the pressure calibrator respectively, and then find out the corresponding force value. Evenly select five test points within the range of 20%~~80% of the full scale of the compression instrument, repeat the test three times at each point according to the process, and calculate the error △A based on the force value of the pressure calibrator according to the following formula. △A does not exceed ±1%. AAm E=Fa × 100
Where: △A——Relative error of force value, %F,—average value of three force values ​​displayed by the compression instrument, N; Fa.-average value of three force values ​​displayed by the pressure gauge, N. Additional remarks:
This standard is proposed by China Light Industry General Association.
This standard is under the jurisdiction of the National Paper Industry Standardization Technical Committee. This standard is drafted by Tianjin Paper Technology Research Institute. The main drafters of this standard are Li Qingxuan, Zhang Jingyan, Wang Fang, and Wang Xiaoping. ***(A1)
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.