Abstract: At present, the domestic shrinkage film shrinkage test method is mainly oil bath method and oven heating method. Based on the standard ISO14616 , this paper introduces a new method for shrink film heat shrinkage performance test, and uses this method to test The shrinkage properties of OPS film, including shrinkage rate, heat shrinkage force and cold shrinkage force, provide reference for the test of shrinkage film heat shrinkage performance by introducing the test principle, equipment FST-02 film heat shrinkage performance tester and test process. . Abstract: Heat shrinkage, shrinkage, heat shrinkage, cold shrinkage, shrink film, film heat shrinkage tester Shrink film is a widely used packaging material, widely used in the packaging and labeling of beverages, beer, dairy products, meat products, medicine, electronic products, plastic products, stationery, books, toys, cosmetics and other products. It has the characteristics of transparency, beautiful appearance, moisture proof and dustproof. Common shrink film includes POF , PE , OPS , PET , PVC , PVDC and so on. The heat shrinkage property of the shrink film is derived from the fact that the molecular chain in the film is de-orientated by heat, and returns to the ability before unstretching, that is, during the production process of the film, when it is in a high elastic state, forced stretching is performed. The molecular chain orientation, when the film is heated again, the molecular chain is de-oriented, returns to the unstretched state, and shrinks the film. The shrinkage properties of different shrink films are not the same. The shrinkage properties of the same film at different temperatures are also different. In addition, the shrink film has a wide variety of products and different shapes. It requires different shrinkage properties, so the shrink film is strengthened. Research and monitoring of heat shrinkage performance is particularly important. At present, the domestic standard method for film shrinkage performance testing is mainly GB/T 12027-2004 " Test method for dimensional change rate of plastic film and sheet heating". The method used in this standard is oven heating method, and some product standards are Requirements for test methods involving product shrinkage performance, such as GB/T10003-2008 "General Purpose Biaxially Oriented Polypropylene (PP) Film", GB/T13519-2016 "Packaging Polyethylene Heat Shrink Film", etc. An oven heating method is used, the latter being an oil bath heating method. Either method can only be used to test the shrinkage rate of the shrink film. The force value generated during the shrinkage process is not well studied, and the value of the shrinkage force value affects whether the shrink film package is tight and whether it causes the product to be crushed. An important factor. In order to investigate the shrinkage and shrinkage of shrink film, this paper uses the method specified in ISO14616 " Test of Shrinkage Properties of Plastic Polyethylene Ethylene Copolymer and Its Mixture Heat Shrink Film " to shrink the shrinkage film, heat shrinkage, and cold. Reduce the force for testing. 1 , the principle of testing This test uses the air heating principle to test. When the temperature in the heating chamber of the equipment reaches the set value, the sample enters the heating chamber for the shrinkage test. The dimensional and force values ​​generated during the shrinkage process are respectively determined by the displacement sensor and the force value. The sensor is monitored in real time. When the force value is reduced to the set value, the sample exits the cavity and continues to monitor the sample size and force value changes. The shrinkage rate is the percentage of the decrease of the length of the sample before and after the test and the ratio of the length of the sample before the test. The force generated during the heating of the sample is the heat shrinkage force, and the force generated during the cooling process of the sample cavity is Cold shrinkage. 2 , test equipment and samples The test equipment used in this paper is the FST-02 film heat shrinkage performance tester independently developed by Labthink . The device has high-precision force value sensor and displacement sensor, which can accurately measure the heat shrinkage performance parameters of the sample. The shrinking force range is 0.2 ~ 30 N , the measurement accuracy is ±0.2% , and a wider range of force can be customized according to special needs. Value; heat shrinkage displacement range is 0.125 ~ 70 mm , measurement accuracy is ±0.125 mm ; heating chamber operating temperature range is room temperature ~ 210 °C , temperature control accuracy ± 0.5 °C ; can test 1 ~ 3 sets of samples at the same time , can be tested The sample size is 130 mm × 15 mm . The equipment meets many national and international standards, such as ISO 14616 and DIN 53369 , to accurately quantify the heat shrinkage, shrinkage and shrinkage of plastic films during heat shrinkage. Figure 1 FST-02 film heat shrinkage performance tester The sample used in the test was a biaxially oriented polystyrene OPS shrink film. Due to its good performance and environmental friendliness, the material is gradually replacing the traditional PVC label as a new type of shrink label. 3 , the test process 3.1 cutting Ten specimens with a width of 15.0 mm were cut transversely along the OPS sample , and the length was such that there was an effective length of 100 mm between the clamps . A special sampler is used to form two circular holes on the surface of each sample to facilitate the clamping of the sample. Each of the two samples is a set for testing the shrinkage and shrinkage of the sample. 3.2 Loading Take any three sets of samples and clamp them to the three sets of fixtures of the equipment. Each set of clamps includes two sample clamps with force value sensor and displacement sensor respectively. The clamped specimen should be completely straight and the force sensor should be free of force. Figure 2 sample clamping diagram 3.3 parameter settings Set test parameters such as test temperature and end temperature, click the Start Test option, and the test starts. 3.4 test process When the temperature in the heating chamber of the equipment reaches the test temperature, the sample automatically enters the cavity, and the test starts to be timed. The sample shrinks by heat and generates heat shrinkage force. When the force value drops to 15%~30% of the large heat shrinkage force of Zui , The sample is automatically ejected, and the force generated thereafter is the cold shrinkage force. The device automatically records and displays in real time the heat shrinkage, cold shrinkage, and shrinkage of the sample into the cavity to the end of the test. After the test, the equipment showed the shrinkage rate of each set of samples, the large heat shrinkage force of Zui, and the large shrinkage force of Zui. The remaining two sets of samples were clamped to the device for testing. 4 , test results This test tested the shrinkage properties of OPS shrink film samples at 110 ° C and 120 ° C. The test results are shown in Table 1 . Table 1 OPS sample shrinkage performance test results Shrinkage performance Shrinkage rate (%) Zui large heat shrinkage (N) Zui large shrinkage force (N) 110 °C 120 °C 110 °C 120 °C 110 °C 120 °C 1 31.78 35.67 2.66 2.38 3.23 3.05 2 30.25 35.94 2.47 2.42 3.04 3.09 3 31.36 36.11 2.59 2.17 3.18 3.28 4 30.28 35.83 2.16 2.03 2.99 3.16 5 29.99 35.78 2.60 2.36 3.27 3.38 average value 30.73 35.87 2.50 2.27 3.14 3.19 5 , conclusion From the shrinkage performance of the OPS shrink film sample measured under two temperature conditions, the shrinkage rate of the sample at 120 °C is slightly higher than 110 °C , and the large heat shrinkage force and the large shrinkage force of Zui at both temperatures are both There is little difference, that is, the shrinkage force does not change much with temperature; the large shrinkage force of the tested OPS sample is significantly larger than the large heat shrinkage force of Zui, indicating that the shrinkage film produces greater compaction force during the cooling process; The deviation of the sample test results is small and the repeatability is good. The FST-02 film heat shrinkage tester developed according to the ISO14616 principle can simultaneously test the shrinkage, heat shrinkage and shrinkage of the shrink film, compared with the conventional oil bath method and oven heating method. The method can more fully reflect the heat shrinkage performance of the shrink film, and can be better applied to the research and quality monitoring of the shrink film. Vegetarians Size 3 Empty Capsule Vegetarians Size 3 Empty Capsule,Natural Empty Vegetable Hard Capsules,Empty Veggie Capsules,Empty Vegan Pill Capsules Ningbo Jiangnan Capsule Co., Ltd. , https://www.jncapsule.com
