Military food is an important area of ​​food research. Due to the special use of military foods, the technical indicators of military foods in processing technology, nutrition and packaging are more stringent than those of civilian foods, and the requirements for military food packaging are also extremely strict. Labthink (Jinan Languang Electromechanical Technology Co., Ltd. 053185068566) is an excellent provider of testing instruments and inspection services, especially for the quality control and testing of military food packaging, with a view to making military-related food packaging quality for military-related enterprises. The control method is well understood.
1. Detection of heat seal strength of military food packaging The heat seal strength test of military food packaging is also called heat seal strength test, which can be tested according to QB/T 2358 (instead of ZBY 28004). On the side, back, top or bottom of the military food packaging bag, samples were taken perpendicular to the heat sealing portion, and each was used as a heat sealing sample on the side, back, top or bottom of the packaging bag. The sample to be taken has a required width of 15 ± 0.1 mm and a developed length of 100 ± 1 mm. However, when a sample with a length of 100 ± 1 mm cannot be taken, the same material as the bag can be bonded with a cellophane adhesive tape to make the sample unfolded to a length of 100 ± 1 mm.
Here, Labthink Languang's XLW (PC)-500 intelligent electronic tensile testing machine is used as an example to introduce the test process. The heat-sealed part is centered and unfolded at 180°. The two ends of the sample are respectively clamped to XLW (PC). On the two clamps of the intelligent electronic tensile testing machine, the vertical axis of the sample should coincide with the center line of the upper and lower clamps, and it should be elastic tight to prevent the sample from slipping and breaking in the fixture. Adjust the initial distance between the test machine fixtures to 50mm, set the test speed to 300mm/min, and start the test to test the heat sealing strength. The test result is the arithmetic mean of 10 samples as the heat sealing strength of the part, expressed as N/15mm. Three significant digits. When testing, it should be noted that if the sample is broken in the fixture, the sample is discarded and the sample is taken.
In addition, if testing in the laboratory, it is necessary to equip the HST-H3 heat seal tester, which simulates the test conditions of the military food packaging production line for hot-press sealing of the packaging materials, and realizes the real sample through the use of the two machines. Preparation and testing purposes.
2, military food packaging barrier performance testing Military food packaging barrier testing is essential for military food, military foods mostly contain oil, the most critical factor affecting the storage period of such foods is the oxidation of fat. Therefore, such products must have good oxygen barrier properties. In addition, some dry products themselves require better storage properties, such as dehydrated foods, which can be stored for a long time as long as they prevent absorption of water. Therefore, the barrier performance test for military food packaging can not be ignored. Barrier testing includes gas barrier performance and moisture barrier performance testing. To test the barrier performance, it is necessary to equip the VAC series differential pressure gas permeation instrument or the PERME OX2/230 oxygen transmission rate test system; to detect the moisture resistance (water vapor transmission), the TSY-T series moisture permeability tester is required. Water vapor transmission rate test system with PERME W3/330 series.
3, military food packaging peeling performance testing Military food packaging is currently more commonly used in composite film bags, such as aluminum-plastic packaging. The composite film structure of military food packaging should not only consider the mechanical strength at normal temperature, but also the mechanical strength of the packaging material at the heat sealing temperature. The packaging materials in the military food packaging process are subjected to various kinds of forces, especially in the heat sealing process, because the strength of the whole material is low at the heat sealing temperature, the interlayer separation is easy to occur, and the composite film is required to be ensured. Reliable composite performance requires the determination of the peeling performance of the composite film for military food packaging. Here, Labthink's XLW (PC) series of intelligent electronic tensile testing machine is taken as an example.
For the detection method, refer to GB8808 "Soft Composite Plastic Material Peeling Test Method". First, remove both ends of the sample width direction by 50 mm, and evenly cut 5 longitudinal and horizontal specimens along the width direction of the sample. The composite direction is longitudinal. The composite layer and the substrate were peeled off 50 mm in advance along the length of the sample, and the stripped portion was not damaged. If the sample is not easily peeled off, the sample may be immersed in a suitable solvent for about 20 mm at one end. After the solvent is completely volatilized, the peeling force test is performed.
During the test, the two ends of the stripped part of the sample are respectively clamped on the upper and lower jigs of the XLW (PC) intelligent electronic tensile testing machine. When clamping, it is necessary to pay attention to the longitudinal wheel and the upper part of the sample stripped. The center of the lower fixture is overlapped and it is suitable for tightness. Set the test speed of the intelligent electronic tensile machine to 300mm/min and start the test for testing. During the test, the unstripped portion was T-shaped in the direction of stretching (as shown below).
4. Adaptability of packaging materials for military food packaging and packaging machines (coefficient of friction or smoothness detection)
The friction in the packaging of military foods is often both a driving force and a resistance, so the size should be controlled within an appropriate range. For automatic packaging coils, it is generally required to have a small inner layer friction coefficient and a suitable outer layer friction coefficient. The outer layer friction coefficient is too large, which may cause excessive resistance during the packaging process, causing tensile deformation of the material, if too small It will also cause the drag mechanism to slip, causing the electric eye tracking and cutting positioning to be inaccurate. However, the coefficient of friction of the inner layer may not be too small. In some cases, the friction coefficient of the inner layer is too small, which may cause the stack to be unstable and produce wrong edges during the forming of the bag. For the composite film for the strip package, the inner layer friction coefficient is too Small may also cause the positioning of the blank to be inaccurate. Therefore, the test of the friction coefficient is extremely important, and it can be inspected by the MXD-02 series friction coefficient meter. The test is carried out in accordance with standards such as GB 10006 or ISO 8259 "Method for Measuring Friction Coefficient of Plastic Film and Sheet". In addition, when studying the friction coefficient, special attention should be paid to the influence of temperature on the friction coefficient. Therefore, it is necessary to measure not only the friction coefficient of the packaging material at normal temperature, but also the friction coefficient at the actual use ambient temperature. The FBR-F1 friction coefficient/peel tester can be used for the lower friction coefficient test.
5, military food packaging heat seal leakage seal problem Military food packaging leakage seal is due to certain factors, so that the part should be combined by heating and melting, not sealed. There are several reasons for leak sealing:
a. The heat sealing temperature is not enough. The same packaging material requires different heat sealing temperatures at different heat sealing locations, different packaging speeds require different heat sealing temperatures, and different packaging ambient temperatures require different heat sealing temperatures. The heat sealing temperatures required for vertical and horizontal sealing of packaging equipment are issues that must be considered in packaging. In addition, for heat sealing equipment, there is also a problem of temperature control accuracy.
b. The sealing part is contaminated. In the filling process of the packaging, the sealing position of the packaging material is often contaminated by the packaging material, and the pollution is generally divided into liquid pollution and dust pollution.
c. Equipment and operational issues. If the heat sealing mold has foreign matter, the heat sealing pressure is not enough, and the heat sealing mold is not parallel.
d. Problems with packaging materials. If the corona is over the surface, there are too many slip agents in the heat seal layer, resulting in poor heat sealing. In order to find this problem in time, in addition to online testing, the laboratory also needs to be equipped with MFY-01 seal tester and LSSD-01 leak and seal strength tester to perform leak seal and leak inspection.