Paper Packaging Container Testing Technology (2)

5. Carton opening force test

In order to facilitate opening, the opening force also needs to be controlled. There are two ways to tear the opening: one is a tearing method using a tape; the other is a pull opening method. The former has a large opening force and is easily damaged in circulation. In order to solve these problems, the opening force of the tearing portion is firstly determined so as to obtain a suitable shape of the pull seal and change the width and the like. Corrugated box tearing force test method shown in Figure 8.

6. Cardboard bond strength test

Paperboard adhesion test is also called peel strength test. This test is a test of the cohesiveness of corrugated board surface, liner paper and corrugated base paper. Insert two rows of metal rods into the empty space of the corrugated board, and apply tension in the opposite direction up and down until it peels off. The pointer reading is the peel strength and the unit is Newton (N).

The test method is shown in Figure 9. This test method can be tested with a small ring pressure tester. There are two ways to test: one is to test the unilateral adhesive force; the other is to measure the adhesive force on both sides of the table. The difference between the two methods is simply that the rods are inserted in different positions.

Corrugated board adhesion is important, but the high adhesion strength is not necessarily good. Because of the excessively high adhesive strength, there are often too many adhesives used, the adhesive area is too large, and even the adhesive flows into the crucible to affect the deformation of the corrugated fiber, which results in a decrease in the compressive strength of the corrugated box. As shown in Fig. 10, the area of ​​the most desirable corrugated cardboard should be viscose 1.5mm and not more than 2mm at the peak. In addition, there are also Shoal type tensile testing machines, which are measured by the Shober type tensile test. Its peel strength A type is 147N or more; B type is 225.4N or more.

7. Stiffness test method

The rigidity of the carton is the ability of the carton to resist deformation. After the carton is under compressive load or full of items, the lack of side stiffness can be easily deformed or even broken. The rigidity of the carton depends mainly on the stiffness of the linerboard.

1 bending rigidity

According to the definition of mechanics, the bending stiffness is the product (EI) of the elastic modulus and the moment of inertia of the section, which can be obtained by the method of bending, as shown in FIG. 11 .

This method is widely used and the method is simple and practical.

c. Resonance method

In this method, an elongated sample is excited to cause resonance, and the elastic coefficient is calculated based on the resonance frequency. This method uses the relationship between the sound propagation velocity inside the material and the elastic modulus to find the elastic modulus, as follows

In each packing unit, five vertical and horizontal readings were taken from different patterns taken out, and the arithmetic average, maximum value, and minimum value of all the measured values ​​in the vertical and horizontal directions were taken as the measurement results.