1 Test principle
The test strip is hung vertically and its lower end is immersed in water, and the capillary absorption height is measured after 10 min. The test is carried out in an open container under a standard environment, and the capillary absorption height is measured with a height difference meter or a ruler.
2 Instruments and reagents
①Use the Krem Tester, the length of the scale is 200mm, and the division value of the scale is 1mm, see Figure 8-23.
② stopwatch. Can be read accurate to 1s.
③Pencil. Even better is an erasable pencil.
④ Reagents used in the test. Distilled water or deionized water, or other solutions as required by product standards.
3 test preparation
① Carry out sampling according to the standard method.
② Carry out temperature and humidity treatment according to the standard method.
③ Cut the sample taken into strips with a width of 15±0.5 mm and a length of 250 mm, with 5 strips in the vertical and horizontal directions.
④ Conduct the test under standard temperature and humidity conditions.
4 test steps
① Place the sample strip flat on a glass plate, and draw a straight line perpendicular to the length direction at a distance of 205 mm from one end. If other immersion depths are used, the distance from this line to the end point should be extended accordingly. Then clamp the sample on the paper clamp so that the horizontal line is aligned with the 200 mm scale of the scale.
② After the sample is clamped, gently lower the beam of the clamper, insert the paper strip vertically into the liquid at 23±1°C for 5 mm, and start the stopwatch at the same time to measure the rise of the liquid level along the sample from the surface. It takes time or the height that the liquid level rises within a certain period of time. Generally, it is expressed by the rising height within 10 min±3 s, or expressed in s/mm or mm/s.
③ When reading the numbers, pay attention to the height of the liquid rising to 1 mm, and the time required for the liquid to rise to a certain distance to be accurate to seconds.
④ If there are special requirements, the liquid absorption time should be stipulated in the product standard.
⑤If the wetting line is inclined or bent when the liquid rises, the result should be read according to the average height. When the absorption speed of the inner and outer layers of multi-layer paperboard is different, the results are expressed as the average value.
⑥The length of the paper strip inserted into the liquid can be appropriately extended according to the product standard or other requirements, but it should be indicated in the test report.
⑦If the sample is crimped, a small clip can be hung at the lower end of the sample. The quality of the selected clip can ensure that the sample is inserted into the liquid vertically without elongating or breaking the sample when it is wet.
5 test results
Calculate the average value of the vertical and horizontal strips. Accurate to 1mm, expressed in mm/10 min, mm/s or s/mm.
