Testing equipment and methods for the hottest corr

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Corrugated base paper, paperboard and carton testing equipment and methods

so far, the characteristics and components of corrugated paperboard have not been tested scientifically and accurately. This is because there are many uncertain factors in the detection process, or it depends on the processing method of paper, paperboard and carton. In addition, in the detection area, the temperature, humidity, the operation of the detection device and the changes of the items in the carton are also one of the reasons. However, it should be wise to establish some guiding testing methods and select those that are important for comparing certain materials, paperboard and applications


in order to standardize various conditions that affect the performance of paper as much as possible, it is necessary to control various conditions reasonably and effectively. In the UK, for example, the test is usually carried out indoors at 50% relative humidity and 23 ℃. The samples shall be properly placed within 24 hours before the test

determination of water absorption

the recognized detection method is Cobb method, but this method is only applicable to facial paper. First clamp the metal ring or cylinder opened at both ends on the paper with a given area and weight, so that the paper weight can effectively close one end of the metal ring or cylinder. The measured quantity of water (usually 25ml) is poured into the storage area, and the residual water is poured out after the specified time. At this time, weigh the paper sample again, and then calculate the water absorption by knowing the weight difference between the front and back, so as to compare the water absorption of different face papers. Generally, the specified test time is about one minute, and the time will be adjusted only when the paper is particularly hygroscopic

and the water drop method can be applied to all papers. This method is relatively easy, but the result is not accurate enough, but it can be tested anytime and anywhere to compare different papers. Usually, draw a circle on the paper as a mark, drop a small amount of water into the center of the circle, and calculate the water absorption of the paper by measuring the water absorption time, that is, the time when the circle is wet

permeability test (paper hole number measurement)

the common method is Gurley test method, which still needs to be measured. However, this time it is the time when quantitative air passes through the specified area on the paper (used here as a diaphragm) under the specified air pressure

the fixed area on the paper is defined by the ring gauge. Then compressed air passes through the diaphragm under the pressure of the specified air pressure, and the amount of gas penetrated can be measured with a manometer. Air permeability is usually expressed in ml/min. Bendsten test method is similar to this method

ring compression strength test (RCT) and other derived test methods (CCT and SCT)

when testing, put a 152 mm (6 inch) long and 12.7 mm (1/2 inch) wide paper tape into the annular groove of a thick steel plate. The steel plate is laid flat, and the length of the paper tape is just enough to form a drum along its annular groove. A horizontal steel plate is placed above the paper roll, and then the paper roll is continuously pressed until it is crushed. The applied pressure is the RCT index of the paper, usually in Newton. This method is mainly used to test facial paper, but it can also be used to test corrugated core paper. The RCT index of these papers can provide a good reference for the final edge pressing strength of paperboard formed in the future

corrugated paper compression strength test (CCT)

this method is specially used to determine corrugated paper. As in the flat pressing strength test of corrugated core paper (CMT compared with the same period last year), the paper becomes the same core paper as the corrugated line after passing through the cold pressing corrugated core paper forming machine. Like the above mentioned RCT test procedure, the formed core paper is also under pressure, and its compressive strength can be calculated at the moment of being crushed

short moment compressive strength test (SCT)

no matter it is RCT test or CCT test, it cannot be repeated, because the shape or vertical state of the paper may change when it is pressed, and the result will not be very accurate when it is retested. Therefore, in order to maintain the consistency of the test, people have developed a short moment compression strength test method for paper. The 15mm wide paper tape is firmly clamped flat with a set of tolerance block splints specially set up by two precision technologies, leaving a gap of 0.7mm (0.030 inch) free paper in the middle. Under hydraulic pressure, one splint moves along the plane of the paper tape to the other splint, squeezing the narrow paper tape in the middle, and it is also necessary to measure the pressure when the paper is crushed. This test can be completed in both machine direction (MD) and machine vertical direction (CD)

corrugated core paper flat compression strength test (CMT)

in the early stage of corrugated board production, insiders believed that it was necessary to measure the flat compression strength of different corrugated core papers, so the corrugated core paper test device came into being. This time, 152 mm 12.7 mm (6 inch 1/2 inch) paper tape will be used. The paper tape can be changed into core paper by putting it into the cold pressing core paper forming machine with the same function as that on the single-sided machine. The core paper can also be formed under the action of the hot roller on the single-sided machine, but it should be stored for a period of time after sticking the tape. The purpose of sticking adhesive tape is to imitate the single-sided paperboard and ensure that the core paper will not deform after being removed from the single-sided machine. This single-sided paper tape can then be placed under pressure and can also be used for RCT test and CCT test. After the paper tape is compressed, there may be two kinds of crushing conditions in the CMT test, either corrugated expansion or side damage. In this way, the core paper and the face paper can be compared and tested. Similarly, the single-sided paper actually produced on the single-sided machine can also be used for testing to compare the actual value and theoretical value of CMT

for hot core paper test, let the sample paper pass through the hot single-sided machine corrugating stick, and then put it between the plywood, and repeat the above steps

moisture test

handheld hygrometer is widely used for moisture test. Before using the hygrometer, calibrate the paper color or surface finish (which affects the divergence of light). In addition, please refer to the instructions provided by the manufacturer

scott interlaminar bonding strength test

stick one end of the sample paper to the metal base and the other end to the top corner member. Strike the vertical face of the angular member with a pendulous pendulum until it separates from the pattern. The energy required to achieve this separation is usually Joule/square meter, so as to generate a pulsed magnetic field synchronized with the high voltage in the arc extinguishing chamber

other tests done by paper mills include pH value test, paper brightness and smoothness test, etc

burst resistance test (also applicable to corrugated paperboard)

the common method is Mullen test method, in which an extended hydraulic elastic circular aperture should be prepared, and a similar paper or paperboard disc sample is placed above it, and the disc sample is just clamped on the upper surface of the aperture. The liquid pressure when the sample breaks will be recorded, that is, the so-called Mullen test value of the sample, usually in kJ/m2

thickness test of paper and paperboard

a micrometer is used to measure the thickness of paper and paperboard. The micrometer can control the pressure and replace the anvil appropriately

gram weight test of paper and paperboard

paper mills often use sensitive test scales to detect the gram weight of a unit of paper and compare it with our standards. Determine the weight and thickness of the gram, and the density of the paper will be known immediately. This method can also be used to determine the weight of paperboard. Paperboard

edge compression strength test (ECT)

this test is quite important, from which we can see the stacking strength of cartons after making cartons with this kind of paperboard, in which the ridge shape of the vertical carton surface is also vertical. This kind of test is similar to CCT, CMT, RCT and FCT tests. The paper tape should be stressed. Both ends of the paper tape should be absolutely horizontal, parallel and perpendicular to the axis. Ect value is the pressure value measured when the cardboard is crushed

The ECT value can be estimated slightly, that is, the RCT value of each side of the paper and the CCT value of the corrugated core paper (taking into account the shrinkage of the paper). For the composite corrugated board with structural thickness that has been bonded for the first time, 10% should be added when calculating the ECT value

flat compression strength test (FCT)

during the test, place the cut round cardboard sample under pressure. Like the CMT test, there may be two kinds of crushing conditions. If not, it is most likely due to the inclination of the ridge

adhesion strength test (PAT)

this test has a long history and is used to test the adhesion strength of corrugated core paper and face paper. The common tool is a special comb. The length of the protruding needle on this comb is twice the width of the cardboard, and the diameter can be placed between the edges of the tested cardboard. Insert a comb from both sides of the rectangular cardboard sample, and then apply pressure to the two combs to separate them, that is, try to separate the face paper and the core paper with upward and downward paper force. The pressure value when the corrugated core paper and face paper are torn is the pat value of the tested paperboard. The adhesive strength of each face paper can also be measured separately, depending on which side of the face paper the protruding needle is inserted into

after the corrugated core paper and face paper are torn apart, it is necessary to check whether the test is really done to make the fixture of the adhesion tester an indispensable part fail, or whether there is a problem with the interlayer adhesion strength of the paper. Generally, the latter is mostly the case

puncture strength test

the test element uses a pendulum with a pointed tool. During the test, drop the pendulum from a predetermined angle to puncture the cardboard sample. The degree of puncture will show the bursting strength of the tested paperboard, and the value will be displayed on a meter


carton compressive strength test

this test requires a large pressure to determine the potential stacking strength of finished cartons, that is, how high can the cartons filled with goods be stacked. This depends not only on the compression strength of the top of the carton to the bottom, but also on the weight of the contents and their own characteristics. If the main containers (such as cans and bottles) containing items have structural vertical strength and are closely arranged in the carton, it will help to improve the compressive strength of the carton. Of course, the pressure on the carton at the bottom of the carton stack determines the required compressive strength of the carton

the results of this test are often far from the actual results. The reason for this difference is either the quality of the cardboard is different, especially the bonding strength of each side of the cardboard is different, or the vertical cardboard surface of the carton is often deformed. These phenomena will occur in the process of filling items, but also in the process of sealing boxes, mainly because the paperboard pressing line is not clear and difficult to identify, or the indentation error is caused by the improper or damaged pressing tools. When folding the flap, it should be clean, otherwise the cardboard near the pressing line will bulge, and it may be crushed under the vertical pressure

however, the compressive strength of cartons also depends on the ECT value and perimeter of cartons and the thickness of cartons. McKee formula is often used to calculate the compressive strength of cartons. The formula is as follows:

bct (kg) =1.515 ect0.57 t0.87 (l+w) 0.47

where ect is the edge compressive strength (kg/cm), t is the thickness of the cardboard (mm), and l and W are the length and width of the carton (mm)

drop test

this test is not only for cartons, but also for the overall protection performance of the packaging such as its contents and some filled cardboard. In the first 50 years of the last century, the test method seemed somewhat rough: throw the test carton from the window on the second or third floor to the concrete pavement in the factory, and watch the results with naked eyes or photos. Later, people also put cartons on the top edge of trolleys

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