This standard specifies the method for measuring the roughness of paper and paperboard using a printed surface roughness tester. This standard is applicable to all kinds of printed paper and paperboard. GB/T 2679.9-1993 Paper and paperboard roughness test method (printed surface method) GB/T2679.9-1993 Standard download decompression password: www.bzxz.net

National Standard of the People's Republic of China
Paper and board-Determination of roughness(Print-surface method)
GB/T 2679.9-93
This standard adopts the international standard ISO8791/4-1992 "Determination of roughness of paper and board (air leakage method) Part 4 Printing surface method".
Subject content and scope of application
This standard specifies the method for measuring the roughness of paper and board using a printing surface roughness meter. This standard is applicable to various printed papers and boards. 2 Reference standards
GB 450 Paper and paperboard sample sampling
GB10739 Standard atmosphere for handling and testing of pulp, paper and paperboard samples 3 Terminology
Print-surf roughness Under specified conditions, the surface of paper or paperboard contacts a circular ring surface of a certain width. The average gap between the paper surface and the ring surface under a certain contact pressure is the print-surf roughness. 4 Principle
Place the sample between a metal measuring ring and an elastic pad, and an inner protective ring and an outer protective ring to seal the sample between the two rings. Under the action of the pressure difference between the inside and outside of the measuring ring, when the airflow passes between the measuring ring and the sample, the airflow velocity is measured, and the measurement result is converted into the size of the air permeability gap, expressed in microns [see Appendix A (Supplement)]. 5 Instruments
5.1 This standard adopts an air-resistance type printed surface roughness tester, and its process is: the gas from the pressure-controlled gas source first passes through an air-resistance element, then passes through the probe, and then is discharged into the atmosphere. A sensor is used to measure the pressure difference through the air-resistance element and across the annular measuring surface respectively. These two pressure differences change with the roughness and convert the signal into the size of the air permeable gap (μm). The process is shown in Figure 1. Filter
Inlet 300 ~ 600 kPa
Pressure regulating valve
Fluid damping
Probe and sample clamping device!
Figure 1 Schematic diagram of air flow of printed surface roughness tester Approved by the State Administration of Technical Supervision on February 15, 1993 Pressure sensor
Analog signal
To the atmosphere
Implemented on October 1, 1993
5.2 Main components of the measurement system
5.2.1 Air source
GB/T 2679.9— 93
Clean air source, free of oil mist and water droplets, with a stable pressure between 300 and 600 kPa. The test pressure is then adjusted to 19.6±0.1 kPa through a pressure regulating valve.
5.2.2 The annular probe (Figures 2 and 3) consists of three coplanar metal annular surfaces that have been ground. The middle ring is 51.0±1.5μm wide, and the radial distance between the two rings is 152±10μm. The measuring ring is centered and equidistant from the inner and outer rings, with a deviation of ±10μm. The three rings form a sealing system, and air can enter the channel between the inner protective ring and the measuring ring, and be discharged from the channel between the outer protective ring and the measuring ring. The back of the probe has a channel connected to the air inlet and outlet, and is machined into a grinding matching plane. The outermost ring of the probe is a pressurized spring protection ring. Protective ring
Air source channel
Measuring ring
Groove to atmosphere
Flowmeter channel
Figure 2 Plan view of measuring ring and protective surface of printed surface roughness tester probe Regulated low-pressure air
Elastic pad
Into flowmeter
Measuring ring
Figure 3 Partial view of printed surface roughness tester probe 5.2.3 Pad holder
A metal disc with a groove, the groove can accommodate an elastic pad, the diameter of which is 10mm larger than the outer protective ring of the probe. 5.2.4 Elastic pad
The elastic pad can be fixed in the groove of the pad holder with double-sided tape. Elastic soft pad: It is composed of a synthetic rubber pad with a thickness of 0.60±0.06mm and a fiber fabric bonded to it, with a total thickness of 2.0±0.2mm. The surface hardness of the entire pad is 83±6IRHD (International Rubber Hardness Unit) Elastic hard pad: It is made of cork, lithographic pad or similar material attached to polyester film, with a total thickness of 2.0±0.2mm and a hardness of 95±2IRHD for the entire pad.
5.2.5 Sample clamping device
The sample clamping device uses compressed air to generate floating pressure through a rubber membrane under controlled conditions to lift the pad holder and make it contact with the probe.
GB/T 2679.9—93
The sample clamping pressure is set at 490±15kPa, 980±30kPa, and 1960±30kPa respectively. The sample clamping speed should reach 90% of the selected sample clamping pressure within 0.4s and reach 99% of the pressure value in about 0.8s. The pressure value should be calculated based on the total area of ​​the measuring surface and the protective surface, and the spring pressure of the probe protection ring and the quality of the pad holder and pad should also be considered. Note: Although the instrument is set with a pressure of 490±15kPa, this pressure is not enough to prevent gas from leaking through the protective ring surface, so it is not recommended to use this pressure.
5.2.6 Measurement system
Use gas resistance elements, pressure sensors and signal generators to measure the amount of air passing through. If there is no leakage in the gas system, it can give a reading accurate to 0.01μm, the effective measurement range is between 0.6~～9.0μm, and the reading time is 3~5s. 6 Preparation of samples
6.1 Take samples according to the provisions of GB450, and process and test samples according to the conditions specified in GB10739. 6.2 Cut at least 10 samples of 100mm×150mm from the extracted paper sample along the horizontal paper width, and mark the front and back. 7 Test stepsbZxz.net
7.1 According to the instrument manual, turn on the power and gas source, and preheat until the instrument is stable. 7.2 Select the pad according to the following principles: use a hard pad for letterpress paper, and use a hard or soft pad for paperboard or other printing methods. 7.3 Select the clamping pressure
Letterpress paper and newsprint: 1960±30kPa. Other printing papers and paperboards: 980±30kPa. 7.4 Check and calibrate the instrument according to the contents of Appendix B (reference) and Appendix C (reference). 7.5 Clamp a sample between the probe and the pad, with the tested surface of the sample facing up, test and read the readings. 7.6 Repeat 7.5 to test other samples. If two sides need to be measured, another group of not less than 10 samples should be prepared to test the other side. Test not less than 10 data for each side.
7.7 Calculate the arithmetic mean, standard deviation or coefficient of variation of the test results for each side. The average value is rounded to 0.01μm. 8 Precision
The test is strictly carried out according to the test procedure. The precision of this method is as follows: At about 1 μm
Repeatability 0.1μm
Reproducibility 0.2μm
At about 6μm
If the instrument is not maintained and calibrated on time, the error will increase. 9 Test report
The test report should include the following:
This national standard number,
b. The mark and description of the sample,
The type of sample pad and the clamping pressure,
Report the average value of the printed surface roughness on both sides of the sample, and report the standard deviation or coefficient of variation and the difference between the two sides as needed; d.
Any test conditions that deviate from this standard.
GB/T 2679.9— 93
Appendix A
Calculation formula for printed surface roughness
(Supplement)
This standard method measures the depth of fine pits on the paper surface through air leakage. The printed surface roughness R expressed in microns, that is, the mean cube root of the gap between the annular measuring surface and the sample surface, is calculated according to formula (A1): 12ubq)/3 × 10 6
Where: u
Viscosity of air at room temperature, Pa.s;
Width of measuring surface, m,
Volume of air flow per unit time, m2/s,
Effective length of the annular measuring surface, m;
△p—pressure difference across the annular measuring surface, Pa. wap
Appendix B
Maintenance of Printing Surface Roughness Tester
(Reference)
B1 Sealing
..... (Al)
Maintain the instrument so that there is no leakage and no obvious damage on the gasket surface. Check the sealing when the clamping pressure is 490kPa and the probe pressure difference is 19.6kPa.
B1.1 When the soft pad is clamped against the probe, check whether the air flow can be detected. If there is air flow, it means that there is gas leakage between the back of the probe and the probe seat. A thin layer of vaseline can be applied on the back of the probe to eliminate this leakage. B1.2 Check if the probe is damaged
B1.2.1 Use a soft and clean material such as leather to carefully clean the end face of the probe. B1.2.2 Place a smooth, scratch-free acetate fiber film between the probe and the hard pad. The film thickness is about 125μm. Note: Dust and fingerprints adsorbed by static electricity will cause the sealing of the film and the measuring ring surface to decrease. Therefore, the film surface should be carefully cleaned. B1.2.3 If the measurement result is not less than 0.8μm, it means that the measuring ring surface may be damaged. The damage of the measuring ring surface should be checked under a 50x stereo microscope. If there is obvious damage, it should be sent to the instrument factory for repair. B2 Probe
The probe should be checked regularly with a stereo microscope to promptly detect residues in the gap between the measuring ring and the protective ring. If necessary, use distilled water, methylated alcohol, acetone or a cleaning agent recommended by the instrument manufacturer to clean it according to the method provided in the instrument manual. B3 Elastic pad
Check the pad surface regularly. If any damage is found, replace it according to the operating instructions of the instrument manual. Pay attention to lay the pad flat. B4 Uniformity of clamping pressure
Put a piece of carbon paper with a layer of white thin paper with good hooks on the top and bottom under the probe to clamp the sample, then take it out to check that the indentation on the thin paper should be continuous and uniform.
GB/T 2679.9 - 93
Appendix C
Calibration of instrument measurement values
(reference)
C1 The instrument should be calibrated once a month using the three-level standard for printed surface roughness issued by the authorized laboratory. The three-level standard is divided into two types: calibration head and three-level standard sample.
C1.1 The calibration head is provided by the instrument manufacturer together with the instrument, but must be calibrated by the authorized laboratory. It is used to calibrate the accuracy of the internal gas system and signal conversion system of the instrument. The probe must be sent to the authorized laboratory for calibration once a year. C1.2 After the third-level standard sample, the polyester sheet with a fleece surface treatment is issued by the authorized laboratory every three months. Each sheet can be used up to three times to calibrate the accuracy of the instrument probe and clamping pressure. C2 Calibrate the instrument with the calibration head
C2.1 According to the operating procedures in the instrument manual, remove the "lower probe" from the instrument and replace it with a calibration head with a thin layer of vaseline on the contact surface. C2.2 Turn on the instrument switch, calibrate and adjust the instrument after preheating. C2.3 Select 1960kPa clamping pressure, complete three roughness measurements, read the instrument display value, and the difference between the average of the three display values ​​and the calibration value of the calibration head should not be greater than ±0.1μm. C3 Calibrate the instrument with the third-level standard sample
C3.1 According to the operating procedures in the instrument manual, turn on the instrument, Preheat, calibrate and adjust the instrument. C3.2 Test the three-level standard sample four times at the position shown in Figure C1 according to the type of pad and clamping pressure indicated in the calibration value of the three-level standard sample. The difference between the average value of the four results and the calibration value shall not exceed 0.1μm. Three-level standard sample
Additional instructions:
This standard is proposed by the Ministry of Light Industry of the People's Republic of China. This standard is under the jurisdiction of the National Papermaking Standardization Center. This standard was drafted by Tianjin Light Industry Papermaking Technology Research Institute. The main drafters of this standard are Hou Weiling, Zhang Jingyan, Gao Rui, Tao Yongjuan, and Zhang Jinying. 291
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