Corrugated cardboard box anti-pressure factors (2)

â–²3. Effect of corrugated board types

The same as the effect of corrugated board type, it is also the problem of how much material is loaded and the thickness of corrugated board. Under other conditions being equal, the order of carton pressure resistance is of course: three watts> double laps> single watts.

â–²4. Effect of moisture content on corrugated cardboard

Figure 3 shows the relationship between the pressure resistance and the moisture content of the corrugated boxes found by experiments.
Figure 3 Carton moisture content and carton pressure resistance

The relationship between the pressure resistance of a corrugated box and its water content can be expressed by the following formula:

　　 Where: P - Corrugated box pressure, N;
A—pressure resistance when water content is 0, N;
X—the moisture content of the corrugated box, %.

As long as you know the resistance of a corrugated carton to a certain moisture content, you can use this formula to calculate the resistance to stress regardless of the moisture content.

For example, the resistance of a corrugated box is measured to be 2400N. At this time, the moisture content of the corrugated box is 13%. When the moisture content of the corrugated box is 10%, what is the pressure resistance of the corrugated box?

Solution: First calculate the pressure resistance a when the moisture content is 0 according to the known conditions (Of course, this is only theoretical data and it is actually impossible to achieve): Because,

and so

a=2400/0.913=2400/0.254=9449 (N)
Corrugated box with a water content of 10% at pressure:
P=9449×0.910=9449×0.349=3298 (N)

From the above calculations, it can be seen that when the moisture content of corrugated boxes drops from 13% to 10%, the pressure resistance can be increased by about 40%. The difference is quite large. This relationship can also be seen from Figure 3. Therefore, when comparing the pressure resistance of corrugated boxes, the moisture content of the cartons must be consistent.

two. Corrugated box design impact on corrugated box pressure

â–²1. Corrugated box box type and carton pressure resistance

FIG. 4 shows the distribution of compressive stress when the periphery of the corrugated box is pressed. When the carton is subjected to stacking pressure, most of the stress is concentrated in the four corners of the box, and the central part of the four sides, the compressive stress is much smaller than the four box corners. From this we can infer:

1 Square carton is more ideal than rectangular carton. Because of the increase in the length of the carton side, its resistance to pressure does not increase proportionately. The increase in the length of the side merely adds to the boundary that bears less pressure, but this is slightly different from the actual test results (see Figure 6);

2 The more box cartons, the greater the pressure resistance. Ordinary slotted cartons are not ideal from a stacking point of view. Because they are easily deformed, the ideal stacking cartons should be cylindrical cartons. Because it has no creases, and its circumference can withstand the same amount of compressive force. But this time, it should not be called a cardboard box, but it should be a paper tube.

In addition, even if the corrugated paperboard is of the same paper and stencil type, and the size of the carton is the same, the pressure resistance of the carton will be different when the box type is different. The following are the actual tests performed on the pressure resistance of different boxes.
1 A single corrugated cardboard of the same material;

2 Test box type (developed according to FEFCO/ASSCO, ICCA approved internationally used international carton box type standard): 0201, 0205, 0512, 0510, 0301 and 0320. 10 for each type of box; 3 outside the size of the test box: 335mm × 365mm × 245mm;

4 Test conditions: measured after conditioning for 24 h at a temperature of 20 °C and a humidity of 65% RH (the following tests are all such test conditions);

5 Test results: The pressure resistance of the most commonly used Type 0201 is 100. Table 6 shows the pressure resistance of these six types of box.

Just the difference of the box type, the pressure resistance of the carton has such a big influence, so when choosing the box type of the carton, it must pay special attention. Of course, when selecting a box type, it is not only necessary to consider the pressure resistance, but also various factors such as the characteristics of the contents, the material consumption, and the convenience of use. For example, the 0320 type corrugated box is more than double the pressure resistance of the 0201 model. This is because the former is a sleeve type carton, and the side and end faces are more than one layer of corrugated cardboard. Obviously, its material consumption is much more than the latter.

Therefore, the most commonly used box type is 0201, and the pressure resistance discussed or calculated below is based on type 0201.


(to be continued)