Source：Link Testing Instruments Co.,Ltd.
Stretch film, also known as shrink film. In the early days, most of the stretch films were blown films. At present, the casting method is used to produce stretch films. This is because the stretch films produced by the casting line have the advantages of uniform thickness and high transparency, and can be applied to the requirements of high magnification pre-stretching. Because single-layer casting cannot achieve single-sided sticking, the application field is limited, so its application is not as wide as the three-layer casting process stretch film, and high-quality stretch film should have high transparency, high longitudinal elongation, and high yield point. It has the characteristics of high transverse tear strength and good puncture performance.
Puncture resistance is a guiding indicator for evaluating the ability of packaging to resist puncture by sharp and hard objects. In the long-term contact with the packaging, if the product contains sharp and hard substances, it is easy to have a strong puncture effect on the wrapping film. If the puncture resistance of the wrapping film is poor, it is easy to be damaged by sharp objects, resulting in loose separation of products or goods, and cannot play a protective role. This is also the reason why stretch film packaging should have high puncture resistance.
Test methods and test instruments
The domestic test method for packaging puncture resistance is mainly based on the relevant puncture performance test part in GB/T21302-2007 "General Principles of Composite Film Bags for Packaging".
This test adopts the LTS-05 intelligent electronic tensile testing machine independently developed and designed by Link Testing Instruments Co., Ltd.
Test principle: The sample is fixed on the fixture, the puncture needle installed on the movable chuck punctures the sample, and the force value change during the puncturing process is recorded by the force sensor and displacement sensor located on the movable chuck.
Test samples and test procedures
Test sample: stretch film provided by a company.
Experimental procedure:
(1) Use a sampler to cut 5 samples with a diameter of 100 mm from the wrapping film sample.
(2) Clamp the sample to the special fixture for puncture test, and fix the fixture on the test equipment.
(3) Set test parameters such as test speed and sample thickness.
(4) Click the Start Test option to start the test. The equipment automatically calculates and displays the final test results.
Test Results and Analysis
The average puncture resistance of the wrapping film samples in this test is 1.46 N. LTS-05 intelligent electronic tensile testing machine is a professional instrument for testing items such as puncture resistance, tensile strength, peel strength and heat sealing strength of plastic flexible packaging. It can truly reflect the puncture resistance of the sample, and its equipment is easy to operate. , High test accuracy.
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