A new method for testing the expansion and heat se

A new method for testing the expansion heat sealing strength of flexible packaging bags

the sealing performance of flexible packaging bags is mainly reflected by the integrity of packaging bags and the sealing performance of sealing edges. Because the current heat sealing technology is widely used in the manufacturing process of flexible packaging bags, the body takes two materials often used in the pharmaceutical packaging industry: polypropylene and polyethylene as models, and the index of the sealing performance of sealing edges is the heat sealing strength. The connection position between different materials is usually the weak point of the overall tightness of the packaging, and the detection of the heat sealing strength of the heat sealing edge of the flexible packaging bag is to ensure that the sealing performance of the heat sealing edge will effectively slow down the tightening problem of the Indian PE market at that time, at least as good as other positions of the bag. However, in practical application, how to detect the heat sealing strength that can reflect the sealing performance of flexible packaging bags has not been correctly understood. This paper will introduce in detail the difference between the expansion heat sealing strength and the tensile heat sealing strength, as well as the detection advantages of the restraint plate test device. Welcome to call:

1 Test of heat sealing strength of materials

the heat sealing strength of materials can be roughly divided into tensile heat sealing strength and expansion heat sealing strength according to the test method. Generally, the tensile heat sealing strength measured by the tensile machine is the ability of the material to resist separation when the force direction is consistent and the force value is uniform (such as peeling). It is especially suitable for evaluating the opening of flexible packaging bags. However, in practical application, the rupture of the hot sealing edge of flexible packaging bags is mainly caused by the pressure from the bag. The direction and magnitude of this pressure are not as clear as the tensile test, and the materials near the hot sealing edge will deform due to partial pressure. This situation can be simulated by pressurizing the packaging bag. The obtained expansion heat sealing strength can better represent the actual heat sealing strength of the flexible packaging bag, and the position with the worst sealing strength in the whole package can be detected. However, since the expanded heat seal strength cannot represent the average strength of the heat seal, there is no correlation between the expanded heat seal strength and the tensile heat seal strength

2. Advantages of restraint plate test

the expansion heat seal strength is related to the size, geometry and materials used of the packaging bag. However, if the packaging bag material is particularly soft (as we all know, some materials can be stretched to more than several times the original length, with high tensile strength and deformation rate), obvious deformation will occur with the increase of pressure, which makes the test of expansion heat seal strength difficult. The restraint plate test device is produced to solve this problem. After using the restraint plate test device, it can effectively inhibit the pressure expansion of the flexible packaging bag material and the extension and deformation of the material, transfer the pressure directly to the hot sealing edge, and greatly improve the uniformity of the applied pressure

the use of the restraint plate test device can make the detection of the expansion and heat sealing strength of flexible packaging bags more accurate and reasonable, and its test environment is also more similar to the actual application environment. Flexible packaging bags are widely used in the packaging of food, tablets, cosmetics, and even daily chemical and small electrical components. The gas in the sealed bag will form a protective airbag for the contents. These flexible packaging bags are often stacked together layer by layer during product transportation and storage, which makes the stress situation of the packaging bags different from the general free expansion and closer to the situation of using the restraint plate test device. Using the restraint plate test device can accurately and quantitatively limit the expansion and deformation of the packaging bag, greatly reduce the pressure on the film, and concentrate and evenly distribute the pressure on the heat sealing edge around the bag. The test results are more closely related to the actual transportation and storage status of packaging bags, so they are more concerned by packaging manufacturers and end-users

3. Lssd-01r restraint plate test device

labthink lssd-01 leakage and sealing strength tester is attached with lssd-01r restraint plate test device, which can be applied to the quantitative determination of sealing strength, heat sealing quality, whole bag bursting pressure and sealing leakage performance of various heat sealing process formed soft packaging parts under the state of restrained expansion, such as various food, drug packaging bags, composite outer packaging bags, etc; At the same time, the restraint plate test device can also evaluate and analyze the self compressive strength, bursting strength and other indicators of the materials used in the flexible packaging bag; The limiting height of the restraint plate is designed in strict accordance with the standard requirements, which can be replaced freely, and the operation is convenient and simple; Under the action of the restraint plate test device, the test load on all parts of the tested package, such as the hot sealing edge, is applied evenly, safely and reliably; Combined with rupture test, creep test and creep to rupture test, the restraint plate test device can be used to test the bursting pressure of flexible packaging bags, leakage under load pressure, creep test and other indicators. The test process of the restraint plate is not complicated, and the specific operation process is as follows:

first, select the detection method according to the requirements of the implemented standard to determine whether the restraint plate test device is needed

second, prepare the sample to be tested, and at the same time, select the appropriate spacing of restraint plates in combination with the size of the sample

third, prepare the restraint plate test device, put the sample to be tested into the test device, and pay attention to the sealing of the probe insertion

fourth, turn on the test device, select the test mode and set the test parameters according to the test object and relevant standards. Officially start the test, inflate and pressurize the flexible packaging bag. Fifth, the program automatically gives the test results

when using the restraint plate test device for detection, special attention should be paid to the influence of the spacing of the restraint plates on the test results. The greater the distance between the restraint plates, the smaller the pressure actually exerted on the hot sealing edge, and the greater the pressure used to maintain the deformation of the material. Therefore, in order to unify the test conditions, it is required to ensure that at least 60% of the expanded surface of the flexible packaging bag directly contacts the restraint plate, and there are also detailed provisions on the determination method of the spacing of the restraint plate

4. Summary

flexible packaging bag is the main form of small packaging at present. The detection of heat sealing strength of heat sealing edge is directly related to the sealing of packaging bag and is the premise to ensure the safety of contents. Compared with the tensile heat sealing strength, testing the expansion heat sealing strength has stronger practical significance. However, the traditional free expansion test method will reduce the practicability of the test results due to the expansion of the flexible packaging bag. By using the restraint plate test device, the pressure on the film material can be most effectively reduced by using the four manufacturing bases set up by Shi natvar in the United States, Asia and Europe, so that the pressure can be more uniform Concentrated on the heat sealing edge of the flexible packaging bag, the test results are more practical because they are closer to the actual transportation and storage state of the flexible packaging bag