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Cardboard bursting strength of the assay
hour：润湖 time：2011-7-10 views:
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The standard equivalent to international standards ISO2759 "board - Determination of bursting of the"
1 Subject Matter and Scope
This standard specifies the determination of the hydraulic principles of gradually increasing cardboard bursting method.
This standard applies to determination of bursting in the 350-5500kPa (3.6-56.1kgf/cm) of various types of paperboard (including corrugated cardboard and solid board).
This standard does not apply to high elongation and multi-layer corrugated cardboard.
2 References
GB/T450 paper and cardboard samples taken
GB/T451.2 paper and cardboard quantitative assay
GB/T4678 paper, cardboard, pulp, the first part of the terms
GB/T10739 pulp, paper and cardboard sample handling and testing of standard atmosphere
3 Terminology
Bursting strength, burst index of 7.36 and 7.37 see GB/T4687--1984.
Principle 4
The required equipment to a certain pressure to the sample clip on the upper and lower chuck, the constant back and forth with a hydraulic pump, the sample film and raised until the sample is broken, the maximum hydraulic pressure applied, the sample bursting.
5 instruments
5.1 chuck system
Firmly and evenly to the sample holder, the upper and lower chuck is the two circular plane parallel to each other, with a grooved flat torus (see Appendix A), is given in Appendix A of the chuck system size.
5.1.1 added on the chuck and the finale with a live ball or similar device connection section to ensure uniform distribution of pressure chuck.
5.1.2 up and down within the chuck should be concentric, the maximum concentricity error shall not exceed 0.25mm, two chuck surface should be flat and parallel to each other, chuck screening method in Appendix B.
5.1.3 To prevent the sample slide, the two should be enough to chuck clamping force between the size of the force in order to not damage the sample is limited, usually not less than the clamping force 690kPa (7kgf/cm) (see Appendix C ). In the determination of corrugated board, the pressure 690kPa (7kgf/cm), although the corrugated cardboard to prevent sliding, but most were collapsed, due to different compressive strength of corrugated board, so in the test report should indicate whether the clamping pressure and corrugated is collapsed.
5.2 Film
5.2.1 The film is circular, made of rubber elastic material, the size specifications in Appendix F.
5.2.2 fixed clamping film, the film on the surface of the chuck than the next lower surface of about 4.7mm.
5.2.3 film of elastic resistance in the film under the protruding 10mm chuck surface, its resistance range of 170-220kPa (1.7-202kgf/cm2), protruding 18mm, its resistance range of 250-350kPa (2.5 -3.6kgf/cm2).
Film should be inspected regularly and found that film does not meet the requirements, should be replaced. Install film, to get rid of all gathered at the film under the air.
5.3 Hydraulic System
Promote the appropriate use of piston liquid (such as: chemical pure glycerol, ethylene glycol with corrosion inhibitors or low-viscosity silicone oil), under uniform pressure to the film, until the sample is broken. Hydraulic system and the use of liquid should be no air bubbles, the amount of fluid delivery piston 170 ± 15mL/min (see Table E). Piston must be driven by the motor.
5.4 Pressure Gauge
5.4.1 Bourdon tube pressure gauge, the gauge range of 25% -75% range. Must not be below 15% and 85% higher than the range. Minimum diameter dial scale 95mm, curvature scale of not less than 270 °. Any point within the scope of work should dial the accuracy of the maximum range of 0.5%. Pressure gauge should vent, dial is divided into at least 70 cells.
5.4.2 The expansion of the gauge are working in should be stable within the range of 20% or less, to the maximum range even when the liquid does not need to lose more than 0.4mL (see Appendix E).
5.4.3 pressure gauge and the friction torque between the pointer about 0.3mN.m. The pointer of inertia within the 1-10g.cm2 appropriate (see Appendix D).
5.4.4 Pressure sensor operation to be negligible inertia, barriers and pressure recorders error less than 0.2%. Digital display devices, the breakdown of the sample, the reading changes less than 1 unit.
5.5 Calibration
Pressure gauge calibration see Appendix D;
Physical inspection of the hydraulic Appendix E;
Examination of the specimen chuck Appendix C;
Film size specifications in Appendix F.
6 samples taken, preparation and handling
6.1 samples taken by GB/T450 the provisions of each sample cut into 100mm × 100mm.
6.2 Sample processing should be GB/T10739 provisions of temperature and humidity.
7 test procedure
Taken and processed according to the standard sample, the test must be at the required standard temperature and humidity conditions.
First, select the appropriate range. Be forecast with a large range of pressure gauge.
The sample into upper and lower chuck between. Chuck on the specimen must be over the entire area. Down on the chuck, to the required pressure. Start the instrument, the appropriate rate of increase in pressure until the sample is broken. Below the piston until the film returned to chuck under the surface, to read pressure gauge (or digital display) pressure, and then lift the chuck. Readings back to zero, to prepare for the next test.
If it is found the specimen slide or rupture due to crushing and abnormal, should be the degree of rounding.
Uniform pieces of paper along the horizontal cut of the sample to the positive and negative samples 10 attached to each film were measured, but a trial was not pressed into the chuck pressure over the sample to be tested.
8 results of calculations
Burst index X (kPa.m2 / g) by the following equation:
Where: P - average bursting strength, kPa;
W - sample quantification, g/m2.
Bursting strength, burst index to take three significant figures.
9 results of precision
Precision of the results depends on the uniformity of the sample and other factors, such as the gauge error, the case of clamping force, pressure rate, the system with or without air, film situations.
Repeatability Reproducibility value items
Range 3.8-8.5 5.8-9.6
Generally <5 10
10 Test report
The test report shall include the following: the number of national standards; use of equipment and number; test standard temperature and humidity conditions;
Bursting average (reported separately when necessary, positive and negative results);
If requested, the report burst index;
Report the results of the coefficient of variation, or 95% confidence interval;
When measured with the clamping pressure;
Determination of corrugated board, corrugated indicate whether the voltage collapse;
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