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Source: Link Testing Instruments Co.,Ltd.

The coefficient of friction is a physical quantity used to characterize the resistance generated when the flexible plastic packaging material contacts with the material itself or with other objects such as packaging machinery and undergoes relative movement during use. In the actual production process, if the friction coefficient of the packaging material is too large or too small, it will have an adverse effect on the production process. Bag making, which not only increases energy consumption, reduces production efficiency, but may even cause tensile deformation of packaging materials, affecting its barrier properties and physical and mechanical properties such as impact resistance and puncture resistance; and the friction coefficient is small, it is easy to This leads to problems such as slippage, deviation, unstable stacking, and wrong sides of the material during use. Therefore, it is of great significance to control the friction coefficient of the flexible plastic packaging roll film within an appropriate range to improve its convenience of use.

The friction coefficient of flexible plastic packaging materials is mainly affected by additives such as slip agents and anti-blocking agents added in the production process of the material, and is also related to the stiffness and hardness of the material itself. Generally speaking, if the amount of lubricant added in the material is large, the material will have better smoothness and a smaller coefficient of friction. In addition, the material itself has high stiffness and high hardness, so it will not be too docile on the surface of the object. , easy to slide, so its friction coefficient is small.

Choice of friction surface

The friction coefficient corresponding to the same material on different friction surfaces is different. In order to truly reflect the friction coefficient of the flexible plastic packaging material in different use links, the appropriate friction surface should be selected during the test. Throughout the entire use process of flexible plastic packaging materials in rolling, bag making, filling, heat sealing, etc., the parts that generate mutual friction include the inner surface (hot cover) and the outer surface (non-thermal cover) of the flexible plastic package, Between the inner surface and the inner surface, between the outer surface and the outer surface, between the inner surface and the production equipment, between the outer surface and the production equipment, so when testing the friction coefficient, the corresponding friction surfaces are the inner surface and the outer surface, respectively. The inner surface faces the inner surface, the outer surface faces the outer surface, the inner surface faces the test bench, and the outer surface faces the test bench. The friction coefficient between different friction surfaces is abnormal, and the impact on the use of flexible plastic packaging is also different. If the friction coefficient between the inner surface and the inner surface is low, it is easy to cause problems such as unstable stacking and wrong heat sealing. If the friction coefficient is too high, it will not be easy to open; the friction coefficient between the inner surface and the outer surface will affect the winding process.

Introduction to detection methods

At present, the domestic testing methods for the friction coefficient of flexible plastic packaging materials are generally based on the method standard GB 10006 "Determination of the friction coefficient of plastic films and sheets". When using this method to test the friction coefficient, in order to ensure that the test results are accurate and can truly reflect the friction coefficient of the sample, the following aspects should be paid attention to:

• During the process of cutting the sample and loading the sample, the part to be tested should not be touched by hand. The surface of the cut sample should be flat, without scratches and wrinkles;

• The clamped sample should be close to the surface of the slider, and the tightness should be as consistent as possible;

• When placing the slider with a small sample on the test bench or the sample, the relative movement direction of the two samples should be parallel to the test direction, and the force measuring system of the equipment should not be stressed;

• When testing the coefficient of friction between the soft plastic packaging and the test table, the test table should be carefully wiped three times in one direction with alcohol cotton before the test to prevent oil and dust on the table from affecting the test results.

Introduction of test equipment

The test equipment used for friction coefficient detection is friction coefficient tester, such as Link Testing LTCOF-05A friction coefficient tester, LTMXS-06 friction coefficient tester, These devices are all produced by Link Testing Instruments Co., Ltd. The company's independent research and development and production, the instrument has high test accuracy, high intelligence, and a wide range of applications. Test of friction coefficient of printed matter, aluminum foil, metal products and other materials and products.

For more details please visit www.linktesting.org