Analysis method for measuring opening property of polyethylene film

Abstract

The invention belongs to the technical field of polyethylene film opening property determination, and particularly relates to an analysis method for determining the opening property of a polyethylene film, which is characterized by comprising the following steps of: (1) preparing two layers of polyethylene films which are tightly attached into a rectangular sample; (2) fixing a lower-layer film at one end of the rectangular sample on a test platform through an adhesive layer a; (3) connecting the fixing hole with a tension arm with a sensor, wherein the other surface of the pressing sheet is completely bonded with the edge area of the upper-layer film 2 at the fixed end of the rectangular sample through an adhesive layer b; and (4) pulling the tension arm with the sensor, and when the upper-layer film 2 and the lower-layer film are completely separated, taking the recorded tension as the opening force for representing the opening property of the film. According to the method, the film does not need to be uncovered in advance, the opening property of the film is not damaged, the opening property of the polyethylene film is completely represented, the opening force is increased along with the increase of the width of the rectangular sample, and quantitative testing is achieved.

Description

Technical Field

[0001] The invention belongs to the technical field of polyethylene film opening determination, and in particular relates to an analytical method for determining the opening of a polyethylene film. Background Art

[0002] Opening property is an important test index of polyethylene film, which is used to measure whether two tightly fitted films are easy to peel off. The greater the force between the two tightly fitted films, the worse the film opening property is, and the harder it is to peel off. There are many reasons for the difficulty in peeling off, such as static electricity, viscosity, vacuum or entanglement of small molecules precipitated from the surface of the film.

[0003] Many corporate standards have relevant requirements for opening properties. For example, Q / SY 03494-2022 "Linear Low-Density Polyethylene Resins for Films" involves relevant requirements for opening properties. However, there is currently no suitable opening property test method. The current opening property test methods are all subjective manual evaluations, which lack a theoretical basis and cannot be quantitatively evaluated.

[0004] At the same time, the existing film peeling test methods all require the two tightly bonded films to be peeled off in advance, that is, the two bonded films are opened first and then the remaining parts of the films are tested, which has destroyed the opening of the original film. Such as GB / T39935-2021 "Determination of Anti-adhesion of Films and Sheets of Plastic Products", GB / T16276-1996 "Plastic Film Adhesion Test Method", GB8808-1988 "Soft Composite Plastic Material Peeling Test Method" and other relevant standards. Summary of the invention

[0005] The purpose of the present invention is to propose an analytical method for determining the opening property of polyethylene film in view of the problems of subjective evaluation and early disclosure existing in the background technology.

[0006] The objective of the present invention is achieved through the following technical solutions:

[0007] The analytical method for determining the opening property of a polyethylene film of the present invention is characterized in that it comprises the following steps:

[0008] Step (1) preparing a rectangular sample by tightly fitting two layers of polyethylene film;

[0009] Step (2) fix the lower film at one end of the rectangular sample on the test platform through the adhesive layer a, the center line of the rectangular sample coincides with the tension direction of the tension arm with the sensor, and the rectangular sample is placed in the center of the test area;

[0010] Step (3) A fixing hole is provided in the middle of one side of the pressing sheet, and a movable connecting piece is used to connect the fixing hole and the tension arm with the sensor, and the other side of the pressing sheet is completely bonded to the edge area of ​​the upper film at the fixed end of the rectangular sample by an adhesive layer b;

[0011] Step (4) pulls the tension arm with the sensor at a fixed rate, and records the tension displayed by the sensor at the same time. When the upper film and the lower film at the fixed end of the rectangular sample are completely separated, record the tension at this time. This tension is the opening force that characterizes the opening of the film.

[0012] The length of the rectangular sample along the center line is the length of the rectangular sample, and the width of the rectangular sample perpendicular to the center line is the width of the rectangular sample.

[0013] The length and width of the adhesive layer b are the same as the size of the pressed sheet, the length of the adhesive layer a is the same as the width of the rectangular sample, and the width of the adhesive layer a is not less than 1 cm.

[0014] The pressed sheet has a thickness of 2 mm, a width of 1 cm, and a length that is the same as the width of the rectangular sample.

[0015] The pressing sheet material is any one of hard plastic, carbon fiber or aluminum alloy.

[0016] The movable connecting piece is made of any one of hard plastic, carbon fiber or aluminum alloy.

[0017] The connection mode of the movable connecting piece is hook connection, thread connection or clamp connection.

[0018] Advantages of the present invention:

[0019] The analytical method for determining the opening property of the polyethylene film proposed in the present invention does not require the film to be uncovered in advance, does not destroy the opening property of the film, and can fully characterize the opening property of the polyethylene film. At the same time, as the width of the rectangular sample increases, the opening force also increases, so quantitative testing can be achieved. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1 This is a schematic diagram of the hardware setup structure of the measurement method of the present invention.

[0021] Figure 2 For the present invention Figure 1 Top view of the .

[0022] The numbers therein represent: 1. lower film; 2. upper film; 3. adhesive layer b; 4. adhesive layer a; 5. pressing sheet; 6. movable connecting part; 7. tension arm; 8. fixing hole; 9. test platform; 10. center line of rectangular sample. DETAILED DESCRIPTION

[0023] The specific implementation of the present invention is further described below in conjunction with the accompanying drawings.

[0024] like Figure 1 , 2 As shown, the analytical method for determining the opening property of a polyethylene film of the present invention is characterized in that it comprises the following steps:

[0025] Step (1) preparing a rectangular sample by tightly fitting two layers of polyethylene film;

[0026] Step (2) fix the lower film 1 at one end of the rectangular sample on the test platform 9 through the adhesive layer a4, the center line of the rectangular sample coincides with the tension direction of the tension arm 7 with the sensor, and the rectangular sample is placed in the center of the test area;

[0027] Step (3) A fixing hole 8 is provided in the middle of one side of the pressing sheet 5, and a movable connecting member 6 is used to connect the fixing hole 8 and the tension arm 7 with the sensor. The other side of the pressing sheet 5 is completely bonded to the edge area of ​​the upper film 2 at the fixed end of the rectangular sample by an adhesive layer b3;

[0028] Step (4) pulls the tension arm 7 with the sensor at a fixed rate, and records the tension displayed by the sensor at the same time. When the upper film 2 and the lower film 1 at the fixed end of the rectangular sample are completely separated, record the tension at this time. This tension is the opening force that characterizes the opening of the film.

[0029] The length of the rectangular sample along the center line is the length of the rectangular sample, and the width of the rectangular sample perpendicular to the center line is the width of the rectangular sample.

[0030] The length and width of the adhesive layer b3 are the same as the size of the pressed sheet 5, the length of the adhesive layer a4 is the same as the width of the rectangular sample, and the width of the adhesive layer a4 is not less than 1 cm.

[0031] The pressed sheet 5 has a thickness of 2 mm, a width of 1 cm, and a length that is the same as the width of the rectangular sample.

[0032] The pressing sheet 5 is made of any one of hard plastic, carbon fiber or aluminum alloy.

[0033] The movable connecting member 6 is made of any one of hard plastic, carbon fiber or aluminum alloy.

[0034] The connection mode of the movable connecting member 6 is hook connection, thread connection or clamp connection.

[0035] Example 1

[0036] Two layers of tightly fitted polyethylene film are cut into rectangular samples with a length of 10 cm and a width of 2 cm; the lower film 1 at one end (fixed end) of the rectangular sample is fixed to the central area of ​​the test platform 9 through an adhesive layer a4, and the center line of the rectangular sample coincides with the pulling direction of the pulling arm 7 with a sensor; a pressed sheet 5 is prepared using hard plastic polymethyl methacrylate (PMMA), and the dimensions of the pressed sheet 5 are 2 mm thick, 1 cm wide, and 2 cm long. A fixing hole 8 is installed in the middle of one side of the pressed sheet 5, and the fixing hole 8 and the pulling arm 7 are connected by a hook made of methyl methacrylate. The other side of the pressed sheet 5 is combined with the upper film 2 at the fixed end of the rectangular sample through an adhesive layer b3; the pulling arm 7 is connected to a tension sensor, and the sensor is used to test the tension. The pulling arm 7 is pulled at a fixed rate of 1 mm / s, and the tension displayed by the sensor is recorded at the same time. When the fixed end of the rectangular sample is completely uncovered, the tension at this time is recorded. This tension is the opening force that characterizes the opening of the film. The test is repeated 10 times, and the results are shown in Table 1.

[0037] Table 1 Opening force test data of Example 1

[0038] Number of experiments 1 2 3 4 5 6 7 8 9 10 Opening force / Newton (N) 0.103 0.109 0.114 0.117 0.117 0.122 0.124 0.130 0.137 0.163

[0039] According to GB / T4882-2001 "Normality test for statistical processing and interpretation of data", the Epps-Pulley test was used to verify the normality of the 10 opening force test data of Example 1, and the test statistic was 0.281. As can be seen from Table 1, when the significance level α=0.05, the p quantile is 0.357, so the null hypothesis is not rejected, and the 10 opening force test data of Example 1 conform to the normal distribution.

[0040] Example 2

[0041] Two layers of tightly fitted polyethylene film are cut into rectangular samples with a length of 10 cm and a width of 5 cm; the lower film 1 at one end (fixed end) of the rectangular sample is fixed to the central area of ​​the test platform 9 through an adhesive layer a4, and the center line of the rectangular sample coincides with the tension direction of the tension arm 7 with a sensor; a pressed sheet 5 is prepared using carbon fiber, and the dimensions of the pressed sheet 5 are 2 mm thick, 1 cm wide, and 5 cm long. A fixing hole 8 is installed in the middle of one side of the pressed sheet 5, and the fixing hole 8 and the tension arm 7 are connected in the form of a carbon fiber clamp. The other side of the pressed sheet 5 is combined with the upper film 2 at the fixed end of the rectangular sample through an adhesive layer b3; the tension arm 7 is connected to a tension sensor, and the sensor is used to test the tension. The tension arm 7 is pulled at a fixed rate of 1 mm / s, and the tension displayed by the sensor is recorded at the same time. When the fixed end of the rectangular sample is completely uncovered, the tension at this time is recorded. This tension is the opening force that characterizes the opening of the film. The test was performed 10 times, and the results are shown in Table 2.

[0042] Table 2 Opening force test data of Example 2

[0043] Number of experiments 1 2 3 4 5 6 7 8 9 10 Opening force / Newton (N) 0.268 0.279 0.288 0.296 0.302 0.322 0.375 0.398 0.406 0.422

[0044] According to GB / T4882-2001 "Normality test for statistical processing and interpretation of data", the Epps-Pulley test was used to verify the normality of the 10 opening force test data of Example 2, and the test statistic was 0.272. As can be seen from Table 2, when the significance level α=0.05, the p quantile is 0.357, so the null hypothesis is not rejected, and the 10 opening force test data of Example 2 conform to the normal distribution.

[0045] Example 3

[0046] Two layers of tightly fitted polyethylene film are cut into rectangular samples with a length of 10 cm and a width of 10 cm; the lower film 1 at one end (fixed end) of the rectangular sample is fixed to the central area of ​​the test platform 9 through an adhesive layer a4, and the center line of the rectangular sample coincides with the tension direction of the tension arm 7 with a sensor; an aluminum alloy is used to prepare a pressing sheet 5, and the dimensions of the pressing sheet 5 are 2 mm thick, 1 cm wide, and 10 cm long. A fixing hole 8 is installed in the middle of one side of the pressing sheet 5, and the fixing hole 8 and the tension arm 7 are connected by an aluminum alloy thread. The other side of the pressing sheet 5 is combined with the upper film 2 at the fixed end of the rectangular sample through an adhesive layer b3; the tension arm 7 is connected to a tension sensor, and the sensor is used to test the tension. The tension arm 7 is pulled at a fixed rate of 1 mm / s, and the tension displayed by the sensor is recorded at the same time. When the fixed end of the rectangular sample is completely uncovered, the tension at this time is recorded. This tension is the opening force that characterizes the opening of the film. The test is repeated 10 times, and the results are shown in Table 3.

[0047] Table 3 Opening force test data of Example 3

[0048] Number of experiments 1 2 3 4 5 6 7 8 9 10 Opening force / Newton (N) 1.023 1.178 1.132 1.147 1.158 1.670 1.903 1.980 2.121 2.232

[0049] According to GB / T4882-2001 "Normality test for statistical processing and interpretation of data", the Epps-Pulley test was used to verify the normality of the 10 opening force test data of Example 3, and the test statistic was 0.264. It can be seen from Table 3 that when the significance level α=0.05, the p quantile is 0.357, so the null hypothesis is not rejected, and the 10 opening force test data of Example 3 conform to the normal distribution.

[0050] Example 4

[0051] Two layers of tightly fitted polyethylene film are cut into rectangular samples with a length of 12 cm and a width of 2 cm; the lower film 1 at one end (fixed end) of the rectangular sample is fixed to the central area of ​​the test platform 9 through an adhesive layer a4, and the center line of the rectangular sample coincides with the tension direction of the tension arm 7 with the sensor; a pressed sheet 5 is prepared using hard plastic polymethyl methacrylate (PMMA), and the dimensions of the pressed sheet 5 are 2 mm thick, 1 cm wide, and 2 cm long. A fixing hole 8 is installed in the middle of one side of the pressed sheet 5. The fixing hole 8 and the tension arm 7 are connected by a hook made of methyl methacrylate. The other side of the pressing sheet 5 is combined with the upper film 2 at the fixed end of the rectangular sample through the adhesive layer b3. The tension arm 7 is connected to the tension sensor. The sensor is used to test the tension. The tension arm 7 is pulled at a fixed rate of 1 mm / s, and the tension displayed by the sensor is recorded. When the fixed end of the rectangular sample is completely uncovered, the tension at this time is recorded. This tension is the opening force that characterizes the opening of the film. The test was performed 10 times, and the results are shown in Table 4.

[0052] Table 4 Opening force test data of Example 4

[0053] Number of experiments 1 2 3 4 5 6 7 8 9 10 Opening force / Newton (N) 0.123 0.166 0.186 0.216 0.230 0.256 0.289 0.299 0.412 0.542

[0054] According to GB / T4882-2001 "Normality test for statistical processing and interpretation of data", the Epps-Pulley test was used to verify the normality of the 10 opening force test data of Example 4, and the test statistic was 0.264. It can be seen from Table 4 that when the significance level α=0.05, the p quantile is 0.357, so the null hypothesis is not rejected, and the 10 opening force test data of Example 4 conform to the normal distribution.

[0055] Example 5

[0056] Two layers of tightly fitted polyethylene film are cut into rectangular samples with a length of 16 cm and a width of 6 cm; the lower film 1 at one end (fixed end) of the rectangular sample is fixed to the central area of ​​the test platform 9 through an adhesive layer a4, and the center line of the rectangular sample coincides with the tension direction of the tension arm 7 with the sensor; a pressed sheet 5 is prepared using hard plastic polymethyl methacrylate (PMMA), and the dimensions of the pressed sheet 5 are 2 mm thick, 1 cm wide, and 6 cm long. A fixing hole 8 is installed in the middle of one side of the pressed sheet 5. The fixing hole 8 and the tension arm 7 are connected by a hook made of methyl methacrylate. The other side of the pressing sheet 5 is combined with the upper film 2 at the fixed end of the rectangular sample through the adhesive layer b3. The tension arm 7 is connected to the tension sensor. The sensor is used to test the tension. The tension arm 7 is pulled at a fixed rate of 1 mm / s, and the tension displayed by the sensor is recorded. When the fixed end of the rectangular sample is completely uncovered, the tension at this time is recorded. This tension is the opening force that characterizes the opening of the film. The test was performed 10 times, and the results are shown in Table 5.

[0057] Table 5 Ten opening force test data of Example 5

[0058] Number of experiments 1 2 3 4 5 6 7 8 9 10 Opening force / Newton (N) 0.332 0.368 0.402 0.423 0.464 0.490 0.512 0.566 0.599 0.614

[0059] According to GB / T4882-2001 "Normality test for statistical processing and interpretation of data", the Epps-Pulley test was used to verify the normality of the 10 opening force test data of Example 5, and the test statistic was 0.069. It can be seen from Table 5 that when the significance level α=0.05, the p quantile is 0.357, so the null hypothesis is not rejected, and the 10 opening force test data of Example 5 conform to the normal distribution.

[0060] Comparative Example 1

[0061] Cut two layers of tightly fitted polyethylene film into rectangular samples with a length of 10 cm and a width of 8 cm; fix the lower film 1 at one end (fixed end) of the rectangular sample to the central area of ​​the test platform 9 through an adhesive layer a4, and the center line of the rectangular sample coincides with the pulling direction of the pulling arm 7 with the sensor; use hard plastic polymethyl methacrylate (PMMA) to prepare a pressing sheet 5, the size of the pressing sheet 5 is 2 mm thick, 1 cm wide, and 4 cm long, and a fixing hole 8 is installed in the middle of one side of the pressing sheet 5, and a hanging piece made of methyl methacrylate is used to hang the pressing sheet 5 on the central area of ​​the test platform 9. The hook connects the fixing hole 8 and the tension arm 7, and the other side of the pressing sheet 5 is combined with the upper film 2 at the fixed end of the rectangular sample through the adhesive layer b3; the tension arm 7 is connected to the tension sensor, and the sensor is used to test the tension. The tension arm 7 is pulled at a fixed rate of 1mm / s, and the tension displayed by the sensor is recorded at the same time. When the fixed end of the rectangular sample is completely uncovered, the tension at this time is recorded. The test is performed 10 times. Because the length of the pressing sheet 5 of the rectangular sample plastic film is shorter than the width of the rectangular sample, the upper and lower layers of the rectangular sample plastic film are separated only in the middle part, and the opening property cannot be characterized.

[0062] Comparative Example 2

[0063] Two layers of tightly fitted polyethylene film are cut into rectangular samples with a length of 8 cm and a width of 4 cm; the lower film 1 at one end (fixed end) of the rectangular sample is fixed to the upper left corner of the test platform 9 through an adhesive layer a4; a sheet 5 is prepared using hard plastic polymethyl methacrylate (PMMA), and the sheet 5 has a thickness of 2 mm, a width of 1 cm, and a length of 4 cm. A fixing hole 8 is installed in the middle of one side of the sheet 5, and a hook made of methyl methacrylate is used to connect the fixing hole 8 and the tension arm 7. The other side of the sheet 5 is combined with the upper film 2 at the fixed end of the rectangular sample through an adhesive layer b3; the tension arm 7 is connected to a tension sensor, and the sensor is used to test the tension. The tension arm 7 is pulled at a fixed rate of 1 mm / s, and the tension displayed by the sensor is recorded at the same time. When the fixed end of the rectangular sample is completely uncovered, the tension at this time is recorded. The test is repeated 10 times. Because the tension direction deviates from the center line 10 of the rectangular sample, the plastic film of the rectangular sample is separated from one side corner first, and the opening property cannot be characterized.

[0064] Comparative Example 3

[0065] Cut two layers of tightly fitted polyethylene film into rectangular samples with a length of 8 cm and a width of 10 cm; fix the lower film 1 at one end (fixed end) of the rectangular sample to the central area of ​​the test platform 9 through an adhesive layer a4, and the center line of the rectangular sample coincides with the tension direction of the tension arm 7 with the sensor; use hard plastic polymethyl methacrylate (PMMA) to prepare a pressing sheet 5, the size of the pressing sheet 5 is 2 mm thick, 0.1 cm wide, and 10 cm long, and a fixing hole 8 is installed in the middle of one side of the pressing sheet 5, and a hook made of methyl methacrylate is used to connect the fixing hole 8 and the pulling arm 7, the other side of the pressing sheet 5 is combined with the upper film 2 at the fixed end of the rectangular sample through the adhesive layer b3; the pulling arm 7 is connected to the tension sensor, the sensor is used to test the tension, the pulling arm 7 is pulled at a fixed rate of 1mm / s, and the tension displayed by the sensor is recorded at the same time. When the fixed end of the rectangular sample is completely uncovered, the tension at this time is recorded. The test is repeated 10 times. Because the adhesive layer between the pressing sheet 5 and the upper layer of the film is too narrow, the pressing sheet 5 is not firmly bonded to the upper layer of the rectangular sample plastic film. During the pulling process, the pressing sheet 5 is separated from the upper film 2, and the opening property cannot be characterized.

[0066] Comparative Example 4

[0067] Cut two layers of tightly fitted polyethylene film into rectangular samples with a length of 8 cm and a width of 10 cm; fix the lower film 1 at one end (fixed end) of the rectangular sample to the central area of ​​the test platform 9 through an adhesive layer a4, and the center line of the rectangular sample coincides with the tension direction of the tension arm 7 with the sensor; use hard plastic polymethyl methacrylate (PMMA) to prepare a pressing sheet 5, the size of the pressing sheet 5 is 2 mm thick, 1 cm wide, and 10 cm long, and a fixing hole 8 is installed in the middle of one side of the pressing sheet 5, and the fixing hole is connected with a spring 8 and the pulling arm 7, the other side of the pressing sheet 5 is combined with the upper film 2 at the fixed end of the rectangular sample through the adhesive layer b3; the pulling arm 7 is connected to the tension sensor, the sensor is used to test the tension, the pulling arm 7 is pulled at a fixed rate of 1mm / s, and the tension displayed by the sensor is recorded at the same time. When the fixed end of the rectangular sample is completely uncovered, the tension at this time is recorded. The test is repeated 10 times. Because the displacement of the pulling arm 7 is short, the spring connection is elastically stretched, resulting in the upper film 2 and the lower film 1 not being separated during the pulling process, and the opening property cannot be characterized.

[0068] Comparative Example 5

[0069] Cut two tightly fitting polyethylene films into rectangular samples with a length of 8 cm and a width of 10 cm; fix the lower film 1 at one end (fixed end) of the rectangular sample to the central area of ​​the test platform 9 through an adhesive layer a4, and the center line of the rectangular sample coincides with the tension direction of the tension arm 7 with a sensor; make a pressing sheet 5 using stainless steel, the pressing sheet 5 has a thickness of 2 mm, a width of 1 cm, and a length of 10 cm, a fixing hole 8 is installed in the middle of one side of the pressing sheet 5, and the fixing hole 8 and the tension arm 7 are connected with a stainless steel hook, and the other side of the pressing sheet 5 is combined with the upper film 2 at the fixed end of the rectangular sample through an adhesive layer b3; the tension arm 7 is connected to a tension sensor, and the sensor is used to test the tension. The tension arm 7 is pulled at a fixed rate of 1 mm / s, and the tension displayed by the sensor is recorded at the same time. When the fixed end of the rectangular sample is completely uncovered, the tension at this time is recorded. The stainless steel pressing sheet 5 and the hook themselves have a large mass, and the gravity generated is large, which greatly interferes with the opening force and cannot characterize the opening property.

[0070] The analytical method for determining the opening property of the polyethylene film proposed in the present invention does not require the film to be uncovered in advance, does not destroy the opening property of the film, and can fully characterize the opening property of the polyethylene film. At the same time, as the width of the rectangular sample increases, the opening force also increases, so quantitative testing can be achieved.

Claims

1. An analytical method for determining the opening property of a polyethylene film, characterized in that: The steps include: Step (1) preparing a rectangular sample by tightly fitting two layers of polyethylene film; Step (2) fix the lower film at one end of the rectangular sample on the test platform through the adhesive layer a, the center line of the rectangular sample coincides with the tension direction of the tension arm with the sensor, and the rectangular sample is placed in the center of the test area; Step (3) A fixing hole is provided in the middle of one side of the pressed sheet, and a movable connecting piece is used to connect the fixing hole and the tension arm with the sensor, and the other side of the pressed sheet is completely bonded to the edge area of ​​the upper film 2 at the fixed end of the rectangular sample by an adhesive layer b; Step (4) pulls the tension arm with the sensor at a fixed rate and records the tension displayed by the sensor. When the upper film 2 and the lower film at the fixed end of the rectangular sample are completely separated, record the tension at this time. This tension is the opening force that characterizes the opening of the film.

2. The method for determining the opening property of a polyethylene film according to claim 1, characterized in that The length of the rectangular sample along the center line is the length of the rectangular sample, and the width of the rectangular sample perpendicular to the center line is the width of the rectangular sample.

3. The method for determining the opening property of a polyethylene film according to claim 1, characterized in that The length and width of the adhesive layer b are the same as the size of the pressed sheet, the length of the adhesive layer a is the same as the width of the rectangular sample, and the width of the adhesive layer a is not less than 1 cm.

4. The method for determining the opening property of a polyethylene film according to claim 1, characterized in that The pressed sheet has a thickness of 2 mm, a width of 1 cm, and a length that is the same as the width of the rectangular sample.

5. The method for determining the opening property of a polyethylene film according to claim 1, characterized in that The pressing sheet material is any one of hard plastic, carbon fiber or aluminum alloy.

6. The method for determining the opening property of a polyethylene film according to claim 1, characterized in that The movable connecting piece is made of any one of hard plastic, carbon fiber or aluminum alloy.

7. The method for determining the opening property of a polyethylene film according to claim 1, characterized in that The connection mode of the movable connecting piece is hook connection, thread connection or clamp connection.

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