At present, color printing packaging box is widely used as a kind of packaging product. It not only has a variety of appearances, but also has very good application performance. Waterproofness is a relatively important goal. We need to master the correct measurement method to know whether its waterproof performance is good or bad. When testing, we should pay attention to the correct control of the method, Now let's introduce the method to test the waterproof performance.

1. Cobb absorption method

Test method: cut the color printing package into 10 round test pieces with a diameter of 125mm. Before placing the corrugated cardboard sample, ensure that the cylinder ring surface and rubber pad in contact with the sample are dry.

Use a glass measuring cylinder to measure 100mL of distilled water and pour it into the cylinder, then place the weighed round corrugated board sample on the circular surface of the cylinder, the measured surface is facing the direction of water, and cover the sample with a gland to fix it on the cylinder. Turn the cylinder 180 ° and start the stopwatch together for timing. Every 5 times of measurement, add a certain amount of water according to the water absorption of the corrugated board sample.

Take down the sample from the cylinder, put it on a piece of absorbent paper, pay attention to the downward side of the sample, put two sheets of absorbent paper on the sample 2 s before the water absorption time, and use a smooth pressure roller on a flat and firm table to reciprocate once in 4 s, so that the surface of the sample shows an anhydrous luster, take out the sample quickly and weigh it to 0.001 g, pay attention to that each sample can only be tested once, Do not reuse. If there is still excess water on the surface after absorbing water with absorbent paper or the sample itself has been penetrated by water, the sample shall be discarded. The Kobe water absorption value of corrugated board can be calculated.

2. Immersion method

Test method: cut the color printing packaging sample into 10 square samples of 100mm × 100mm, put them in a clean container that is pre weighed, and weigh them on the balance. Take the sample out of the container and stab it vertically into the reagent tank containing distilled water. The upper edge of the sample should be 25 mm ± 3 mm below the water surface, and the sample should be prevented from contacting the bottom of the tank and between the samples (small clamps can be used to clamp, but the clamp mouth should be within 5 mm from the sample edge).

The immersion time can be determined according to the following conditions:

Low water resistance: 5min ± 15s; Medium water resistance: 30min ± 60s; High water resistance: 24h ± 15min.

When the sample is immersed in distilled water for a regular time, use tweezers to hold one corner of the sample straight and take the sample out of the distilled water. Clamp the sample for 2min to let distilled water drop. Put the sample back into the original container and weigh it to 0.01g on the balance. You can calculate the water absorption and relative water absorption of color printing packaging.

3. Imitation method

According to the product circulation environment, the contents are boxed for verification, and the time and waterproof effect of the corresponding corrugated board are recorded to comment on the waterproof function of the corrugated box.

The above is the introduction of the methods for testing the waterproof performance of color printing packaging. Because the packaging products are widely used and face different application environments, it is required to have some application characteristics to face the impact of various environments. The waterproof performance should also meet the application requirements. We should pay attention to selecting products from formal manufacturers when purchasing, Only in this way can the quality be guaranteed.

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