Abstract : Liquid milk is often packaged in PE black and white film. However, this type of packaging often causes leakage of liquid milk at the sealing area due to improper sealing strength. How to ensure good sealing strength to meet the sealing effect of intact packaging needs to be carried out Related tests. This article uses the XLW (PC) intelligent electronic tensile tester independently developed by Jinan Languang Electromechanical Technology Co., Ltd. to test the sealing strength of a brand of liquid milk black and white film packaging bags (also known as heat seal strength or heat seal strength or seal strength or seal Strength), details the principle of its detection equipment, operating procedures and application of information and other information, in order to control the liquid milk packaging bag sealing effect to provide a certain technical guidance value.
Keywords : sealing strength, heat sealing strength, heat seal strength, sealing strength, sealing strength, liquid milk, dairy products, PE black and white film packaging bags, soft plastic packaging bags, intelligent electronic tensile testing machine, seal cracking, leakage, heat sealing over
1 , the meaning
The packaging of liquid milk is mainly divided into bagged, boxed and bottled, in which the bagged liquid milk is easy to carry, the cost of the used packaging material is low, and the barrier properties of some bag materials and other important properties can satisfy the liquid milk. Due to the quality requirements during the shelf life, the bag form is quite popular among dairy product manufacturers. The bagged liquid milk is mainly divided into two categories: Bailibao and aseptic pillows. The cost of the aseptic pillow packaging is relatively high. Therefore, considering the popular benefits, the use of Bailibao is more extensive. Bailibao's commonly used materials are black and white films and milky white films. Due to the barrier property of milky white films, the liquid milk packaged has a shorter shelf life, generally only 3-5 days. The addition of a high barrier resin material to the black and white film can prolong the shelf life of the liquid milk in the black and white film package, so the bagged liquid milk is mainly based on black and white film packaging.
Black and white film of liquid milk mainly different types of PE resins as the main raw material, according to the quality of liquid milk select Add-barrier resin material, and then mixing the co-extruded film obtained by the coextrusion of black and white masterbatch. The sealing effect of liquid milk PE black and white film packaging seal is related to the used PE model and its adding ratio and the parameter setting of the heat sealing equipment, if it contains good thermal viscosity, a wide range of heat sealing temperature, and heat sealing of inclusions The relatively good PE type resin can ensure that the sealing heat sealing strength is higher and the sealing performance is better. However, besides ensuring the good heat sealability of the PE black and white film's own material, the heat sealing temperature, pressure, and time set by the heat sealing equipment are also critical to the sealing quality. If the above heat sealing parameters are too large or too small, the parameters will be critical. Causes cracks or leaks in the sealing area of ​​the package. Therefore, liquid milk should be strictly monitored PE monochrome film package closure heat seal effect, typically "seal strength" targets were characterized also known as "heat seal strength", "seal strength", "heat seal strength", the general strength values The bigger the seal is, the stronger the seal is, but the bigger the seal strength is, the better, and it is necessary to comprehensively determine the heat seal effect of the seal in conjunction with the relevant test phenomenon. In this paper, the method of detecting the sealing strength and the test phenomenon are introduced in the case of fresh milk PE black and white film packaging bags.
2 , the status quo
The liquid milk black and white film packaging is mainly in the form of a three-side seal, ie, three sides of the packaging bag are formed by heat sealing. For the detection of the sealing strength of this type of packaging bag, the standard currently used in the country is QB/T 2358-1998 "Test method for heat sealing strength of plastic film packaging bag".
Figure 1 Liquid Milk PE Black and White Film Packaging
3 , test sample
A brand of PE black and white film-packed pure milk was purchased on the market at random .
4 , equipment
In this paper, sealing strength of Labthink XLW (PC) Auto Tensile Tester test milk bags.
Figure 2 XLW (PC) Intelligent Electronic Tensile Testing Machine
4.1 Test principle
The sample is clamped between the two clamps of the clamp. The two clamps move relative to each other. The force value sensor and the built-in displacement sensor on the movable clamp are used to collect the force value change and displacement during the test. Changes were made to calculate the seal strength, tensile, tearing, and deformation rate of the sample.
4.2 Scope of application
(1) XLW (PC) intelligent electronic tensile testing machine is suitable for plastic film, composite materials, soft packaging materials, plastic hoses, adhesives, adhesive tapes, stickers, medical patches, release paper, protective film, closure assembly, sealing the metal foil, a diaphragm, a magnetic card, a nonwoven fabric, rubber, paper products such as stretching, peeling, deformation, tearing, adhesive, puncture force, opening force, tear force, low unwind force , pull-out force, resistance to pressure and other performance tests.
(2) XLW (PC) intelligent electronic tensile testing machine conforms to GB 8808 , GB/T 1040.1 ~ GB/T 1040.4 , GB/T 1040.5 , GB/T 4850 , GB/T 12914 , GB/T 17200 , GB/T 16578.1 , GB/T 7122 , GB/T 2790 ~ GB/T 2792 , GB/T 17590 , QB/T 1130 , QB/T 2358 , ASTM E4 , ASTM D882 , ASTM D1938 , ISO 37 , ASTM D 3330 , ASTM F88 , ASTM F904 , JIS P8113 and many other national and international standards.
4.3 performance parameters
There are 500 N , 50 N two kinds of specifications to choose from, the test precision is as high as 0.5 grades, have guaranteed the accuracy of the test result effectively. The device supports pull and press bidirectional test modes. In both test modes, the test speed can be from 50 mm/min , 100 mm/min , 150 mm/min , 200 mm/min , 250 mm/min , 300 mm/min. , Any setting of 500 mm/min seven modes. Pneumatic clips are used on the device to effectively prevent the specimen from slipping. The long stroke of 1000 mm satisfies the testing of large deformation rate materials. Through intelligent protection such as limit protection, overload protection, and automatic return, user safety is protected. With more than 100 different sample holders for users to choose from, it can meet the testing requirements of more than 1000 kinds of materials, and can provide customized services according to the different test materials.5 , the test process
(1) Use a sampler to cut 10 samples from each heat seal edge of purchased liquid milk packaging bag (required to cut from 3 different packaging bags of the same sample ). The width of the sample is 15 mm . The deployment length is 100 mm .
(2) Set the test parameters such as width, thickness, and test speed in the software configured in the tensile tester.
(3) The sample is unfolded and clamped on the jig so that the long axis direction of the sample coincides with the center line of the jig.
Figure 3 sample clamp
(4) Click the Start Test button in the software to start the test. The system automatically calculates and records the test results.
6 , test results
In front of the package as a basis font from top to bottom on the judgment edge, lower edge, side sealed edges, the average heat seal strength of the cutting edge seal 10 on samples taken from the bag 3 to 20.044 N / For 15mm , the average heat seal strength of the 10 lower seal samples was 19.781 N/15mm , and the average heat seal strength of the 10 side seal samples was 22.407 N/15mm .
7. Conclusion
Of Labthink XLW (PC) intelligent electronic tensile strength tester detects the sealing liquid milk monochrome film bags, having a precise test results, the test efficiency. The device can also be used to test the sealing strength of soft plastic materials such as liquid milk aseptic pillows, aseptic bricks and milky white films. It can also test the peel strength, tensile strength and deformation rate, and puncture resistance of various types of soft plastic packaging. Tear force and other performance, is a versatile, cost-effective detection equipment. In addition to sealing strength, liquid milk packaging needs to focus on its oxygen transmission performance indicators, friction coefficient, sealing, etc., related instrumentation, Labthink provides you with the details of the instrument that you can visit our website to view blue light Call for advice. Labthink expects to enhance the technical exchanges and cooperation with enterprises and institutions in the industry.
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