1. Selection of test method
To measure the adhesive strength of Kraft paper tape, we must first determine the appropriate test method. A common method is the peel test. In this test, a flat, smooth and standard test surface is required, such as a stainless steel plate or a glass plate. Paste the Kraft paper tape on the test surface in a prescribed manner, for example, use a specific pressure roller to roll the tape with uniform pressure to ensure that the tape is in full contact with the test surface and eliminate interference from factors such as bubbles. Then, use a tensile tester to peel the tape from the test surface at a certain angle (usually 180° or 90°) and a constant speed (such as 300mm/min). The tensile tester will record the change in force value during the entire peeling process, and this force value can reflect the adhesive strength of the tape to a certain extent. Another method is the shear test, which pastes the tape between two parallel test surfaces, applies a shear force perpendicular to the tape's pasting surface, and measures the shear force when the tape begins to slide or is damaged, which is very meaningful for evaluating the adhesive performance of the tape when it is subjected to shear force.
2. Consideration of the test environment
The test environment is crucial to measure the adhesive strength of Kraft paper tape. Temperature is a key factor, and different temperatures will significantly affect the adhesiveness of the tape. In a low temperature environment, such as - 20°C, the adhesive may become hard and the adhesiveness will decrease; in a high temperature environment, such as 60°C, the adhesive may become soft or even flow, and the adhesiveness will also change. Therefore, it is necessary to test under different temperature conditions to simulate various temperature scenarios in actual use. Humidity should also not be ignored. A high humidity environment may cause the adhesive to absorb moisture and affect its adhesiveness. For example, when the relative humidity reaches more than 80%, the adhesiveness of the tape may decrease. Therefore, in addition to testing under standard humidity (such as 40% - 60%), testing should also be carried out in a high humidity environment, so as to fully understand the performance of the adhesive strength of the tape under different humidity conditions.
3. The influence of pasting time
The adhesive strength of Kraft paper tape is also related to the pasting time. When it is just pasted, the bond between the tape and the adhered object may not have reached the optimal state. As time goes by, the adhesive will gradually penetrate and solidify, and the bond with the adhered object will become stronger. Therefore, when measuring the adhesive strength, it is necessary not only to test the immediate adhesiveness after pasting, but also to test the adhesiveness after a period of time. For example, the test can be carried out 24 hours and 48 hours after pasting to observe the change in adhesive strength. In this way, the adhesive performance of the tape in actual long-term use can be more accurately evaluated.
4. Sample preparation and repeatability test
In order to accurately measure the adhesive strength of Kraft paper tape, the sample preparation must be strictly carried out in accordance with the standard. The length, width and other dimensions of the tape must comply with the regulations, and the consistency of the operation must be ensured during the pasting process. At the same time, in order to ensure the reliability of the test results, repeatability tests are required. Generally speaking, at least 5-10 tests should be carried out under each test condition, and the average value is taken as the final adhesive strength value. This can reduce the error in a single test, so that the measurement results can more truly reflect the adhesive strength of Kraft paper tape.
