Method for testing cross stripping performance of PET (Polyethylene Terephthalate) polar eardrum

Abstract

The invention belongs to the technical field of tab stripping performance testing, and particularly relates to a PET tab cross stripping performance testing method which comprises the following steps: S1, cutting a PET tab sample to obtain a sample, and marking an inner surface and an outer surface; s2, setting the outer surface of the sample to be upward, fixing the outer PP layer, and pulling the middle PET layer for separation; s3, enabling the inner surface of the sample stripped in the step S2 to face upwards, fixing the inner surface PP layer, and pulling the middle PET layer for separation; s4, setting the tension parameter of the tensile machine as D, and clamping the outer PP layer by using the tensile machine to obtain the average stripping force D1 of the outer PP layer within the data reading range; s5, clamping the inner surface PP layer by using a tensile machine to obtain the average stripping force D2 of the inner surface PP layer in the data reading range; s6, observing the layering damage condition of the sample after the two surfaces of the sample are stripped; and step S7, comparing D1 and D2 with D respectively, determining that the stripping force is normal when both D1 and D2 are greater than D, and determining that the stripping force is abnormal when either of D1 and D2 is greater than D.

Description

Technical Field

[0001] The invention belongs to the technical field of tab film peeling performance testing, and in particular relates to a cross-peeling performance testing method for a PET tab film. Background Art

[0002] The tab film is a component of lithium-ion battery products. It is the contact point during charging and discharging. Its performance and quality directly affect the safety and stability of the battery. Therefore, during the battery production process, the tab needs to be strictly controlled and tested. The PET tab film is a three-layer film composed of different materials in the PET and PP layers. The PET tab film is stretched and layered. The current method is to use both hands to gently pull the two sides of the scratch to slowly separate the PP layer from the middle PET layer. Due to the different elongation rates of the PP layer and PET, it is difficult to stretch them synchronously. At a certain distance, they will break and the peeling performance cannot be obtained.

[0003] Therefore, providing a testing method that can accurately characterize the peeling performance of PET tab films is a technical problem that urgently needs to be solved in this field.

[0004] It should be noted that the above information disclosed in this background technology section is only used to understand the background technology of the present application concept, and therefore, the above description is not considered to constitute information of the prior art. Summary of the invention

[0005] The embodiments of the present disclosure at least provide a method for testing the cross-peeling performance of a PET tab film.

[0006] In a first aspect, an embodiment of the present disclosure provides a method for testing the cross-peeling performance of a PET tab film, comprising the following steps: step S1, cutting the PET tab film to obtain a sample, and marking the inner and outer surfaces; step S2, setting the outer surface of the sample to face upward, lightly scratching a first shallow mark on one side between the outer PP layer and the middle PET layer of the sample, smearing the first shallow mark with a solvent, expanding the first shallow mark to a first opening, fixing the outer PP layer and pulling the middle PET layer to separate; step S3, facing the inner surface of the sample peeled off in step S2 upward, lightly scratching a second shallow mark on one side between the inner PP layer and the middle PET layer of the sample, the first shallow mark and the second shallow mark being located at the first opening, respectively. The two sides of the sample are smeared with a solvent for a second shallow mark, and the second shallow mark is enlarged into a second opening. After fixing the inner PP layer, the middle PET layer is pulled to separate; step S4, setting the tension parameter of the tensile machine to D, clamping the outer PP layer with the tensile machine, and obtaining the average peeling force D1 of the outer PP layer within the data reading range; step S5, clamping the inner PP layer with the tensile machine, and obtaining the average peeling force D2 of the inner PP layer within the data reading range; step S6, observing the delamination and damage of the two sides of the sample after peeling, and the sample data without damage enters step S8; step S7, respectively compare D1 and D2 with D, when D1 and D2 are both greater than D, the peeling force is normal, and if any one of them is not satisfied, the peeling force is abnormal.

[0007] In an optional embodiment, the size of the sample in step S1 is 15 mm*120 mm.

[0008] In an optional embodiment, the depths of the first shallow mark and the second shallow mark range from 10 to 15 mm; the depths of the first opening and the second opening range from 12 to 20 mm.

[0009] In an optional embodiment, the separation distance in steps S2 and S3 is 1-5 cm.

[0010] In an optional embodiment, the method of fixing the outer PP layer and the inner PP layer in steps S2 and S3 includes using a steel ruler to resist; wherein the contact angle of the steel ruler is 130-150°, and the contact width is 10-20 mm.

[0011] In an optional implementation, the average value of the tension parameter D in step S4 is 5N.

[0012] In an optional implementation, the parameters set in step S4 further include the upper and lower clamp spacing, the peeling speed, the test change point distance and the data reading range.

[0013] In an optional implementation, the setting range of the distance between the upper and lower clamps is 3-5 cm.

[0014] In an optional embodiment, the peeling speed is set in the range of 50-200 mm / min.

[0015] In an optional implementation, the data reading range is 15-55 mm; the distance range between the test change point and the initial point of the tensile machine is 60-80 mm.

[0016] The beneficial effect of the present invention is that the cross-peeling performance testing method of the PET tab film achieves the effect of obtaining the peeling force performance of the inner and outer PP layers on the same tab film sample by cross-peeling the double-sided PP layers, and adopts a segmented opening to ensure the integrity of the film layer, which can reflect the most realistic performance of the PET tab film.

[0017] Other features and advantages of the present invention will be described in the following description, and partly become apparent from the description, or understood by practicing the present invention. The purpose and other advantages of the present invention are realized and obtained by the structures particularly pointed out in the description, claims and drawings.

[0018] In order to make the above-mentioned objects, features and advantages of the present invention more obvious and easy to understand, preferred embodiments are given below and described in detail with reference to the accompanying drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] In order to more clearly illustrate the specific implementation methods of the present invention or the technical solutions in the prior art, the drawings required for use in the specific implementation methods or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are some implementation methods of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0020] Figure 1 A schematic diagram of a cross-peeling performance test method for a PET tab film provided in an embodiment of the present disclosure; Figure 2 Actual pictures of inner and outer surface PP cross-peeling (A inside, A outside) and single-sided PP peeling (D inside) provided in the embodiments of the present disclosure.

[0021] In the figure: 1. Outer PP layer; 2. Middle PET layer; 3. Inner PP layer. DETAILED DESCRIPTION

[0022] In order to make the purpose, technical solution and advantages of the embodiments of the present invention clearer, the technical solution of the present invention will be clearly and completely described below in conjunction with the accompanying drawings. Obviously, the described embodiments are part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0023] As used herein, the phrases "in one embodiment," "according to one embodiment," "in some embodiments," and the like generally refer to the fact that the particular feature, structure, or characteristic following the phrase may be included in at least one embodiment of the present disclosure. Therefore, a particular feature, structure, or characteristic may be included in more than one embodiment of the present disclosure, so that these phrases do not necessarily refer to the same embodiment. As used herein, the terms "example," "exemplary," and the like are used to "serve as an example, instance, or illustration." Any implementation, aspect, or design described herein as "example" or "exemplary" is not necessarily to be construed as preferred or superior to other implementations, aspects, or designs. On the contrary, the use of the terms "example," "exemplary," and the like is intended to present concepts in a concrete manner.

[0024] Herein, example embodiments of the present disclosure will be described in more detail with reference to the accompanying drawings. As used herein, expressions such as "at least one of..." when following a list of elements modify the entire list of elements rather than modifying individual elements in the list. For example, the expression "at least one of a, b, and c" should be understood to include only a, only b, only c, both a and b, both a and c, both b and c, or all of a, b, and c.

[0025] The terms used herein are only used to describe specific exemplary configurations and are not intended to be limited. As used herein, the singular articles "one", "an" and "the" may also be intended to include plural forms, unless it is clearly indicated above that this is not the case. The terms "comprise", "include" and "have" are inclusive, and therefore specify the presence of features, steps, operations, elements and / or components, but do not exclude the presence or addition of one or more other features, steps, operations, elements, components and / or combinations thereof. The method steps, processes and operations described herein should not be interpreted as necessarily requiring them to be performed in the specific order discussed or shown, unless specifically identified as an execution order. Additional or alternative steps may be adopted.

[0026] Some embodiments of the present invention are described in detail below. In the absence of conflict, the following embodiments and features in the embodiments can be combined with each other.

[0027] The embodiment of the present disclosure provides a cross-peeling performance test method for a PET tab film, comprising the following steps: step S1, cutting the PET tab film to obtain a sample, and marking the inner surface and the outer surface; step S2, setting the outer surface of the sample upward, lightly scratching a first shallow mark on one side between the outer PP layer and the middle PET layer of the sample, smearing the first shallow mark with a solvent, expanding the first shallow mark into a first opening, fixing the outer PP layer and pulling the middle PET layer to separate; step S3, facing the inner surface of the sample peeled in step S2 upward, lightly scratching a second shallow mark on one side between the inner PP layer and the middle PET layer of the sample, the first shallow mark and the second shallow mark are respectively located on both sides of the sample and apply a solvent to a second shallow mark, expand the second shallow mark to a second opening, fix the inner PP layer and then pull the middle PET layer to separate it; step S4, set the tension parameter of the tensile testing machine to D; step S5, clamp the outer PP layer with the tensile testing machine to obtain the average peeling force D1 of the outer PP layer within the data reading range; step S6, clamp the inner PP layer with the tensile testing machine to obtain the average peeling force D2 of the inner PP layer within the data reading range; step S7, observe the delamination and damage of the two sides of the sample after peeling, and the data of the sample without damage enters step S8; step S8, compare D1 and D2 with D respectively, when D1 and D2 are both greater than D, the peeling force is normal, and if any one of them is not satisfied, the peeling force is abnormal.

[0028] In an optional embodiment, the size of the sample in step S1 is 15 mm*120 mm.

[0029] In an optional embodiment, the depth range of the first shallow mark and the second shallow mark is 10-15mm; the depth range of the first opening and the second opening is 12-20mm, and after obtaining the scratch, it is smeared with alcohol and wiped clean after 3-5s to obtain the opening to provide sufficient clamping area for the tensile machine.

[0030] In an optional embodiment, the separation distance in steps S2 and S3 is 1-5 cm.

[0031] In an optional embodiment, the method of fixing the outer PP layer and the inner PP layer in steps S2 and S3 includes using a steel ruler to resist; wherein the contact angle of the steel ruler is 130-150°, and the contact width is 10-20 mm. The setting of the steel ruler can ensure that the PP layer cannot move, and at the same time, as the opening increases, the steel ruler needs to be followed to the inside of the opening.

[0032] In an optional implementation, the average value of the tension parameter D in step S4 is 5N.

[0033] In an optional implementation, the parameters set in step S4 further include the upper and lower clamp spacing, the peeling speed, the test change point distance and the data reading range.

[0034] In an optional implementation, the setting range of the distance between the upper and lower clamps is 3-5 cm.

[0035] In an optional embodiment, the peeling speed is set in the range of 50-200 mm / min.

[0036] In an optional implementation, the data reading range is 15-55 mm; the distance range between the test change point and the initial point of the tensile machine is 60-80 mm.

[0037] See also Figure 1 ,like Figure 1 As shown, the cross-peeling performance test method of the PET tab film includes the following steps: Step S1: Cut the sample into 15mm*120mm, and write the inner and outer surfaces and batch number on the cut sample; Step S2, with the outer side of the sample facing upward, use a knife to gently cut the right edge of the PP layer on the outer side of the sample without damaging the middle PET layer, apply a little alcohol on the scratch position, and gently pull both sides of the scratch with both hands to slowly separate the outer PP layer and the middle PET layer, and then use a steel ruler to press against the pulled outer PP layer to prevent it from moving, and use a uniform force to slowly pull the PET composite layer to separate it. The steel ruler should move forward and press against it every time the distance is separated, and then use a uniform force to slowly pull the PET composite layer to separate it again; Step S3, turn the sample peeled in step S2 over with the inner side facing upward, use a knife to gently cut the left edge of the PP layer on the inner side of the sample without damaging the middle PET layer, apply a little alcohol on the scratch position, and gently pull both sides of the scratch with both hands to slowly separate the inner PP layer and the middle PET layer, and then use a steel ruler to press against the pulled inner PP layer to prevent it from moving, and use a uniform force to slowly pull the PET composite layer to separate it. The steel ruler moves forward and presses against it every time the distance is separated, and the PET composite layer is slowly pulled with a uniform force again to separate it; Step S4, setting parameters for the tensile testing machine include: the distance between the upper and lower clamps is 3cm, the peeling speed is 100mm / min, the test change point is 65mm, the data reading range is 15-55mm, the middle layer PET surface is facing oneself before clamping the sample, and the upper and lower clamps of the tensile testing machine are used to clamp the S2 peeling surface respectively. During the peeling process, observe whether the sample has delamination and damage, and record the average value D1 of the data reading range after the peeling is completed; Step S5, clamp the sample with the PET surface of the middle layer facing yourself, and clamp the S3 peeling surface with the upper and lower clamps of the tensile machine respectively. Observe whether the sample has delamination and damage during the peeling process, and record the average value D2 of the data reading range after the peeling is completed; Step S6, after the PP layers on both sides are peeled off, it is observed that there is no delamination or damage on the sample, which means the sample is qualified; Step S7, compare D1, D2 with the set value D, if D1, D2>D the peeling force is normal, if D1, D2<D the peeling force is abnormal, if any one of them is not satisfied the peeling force is abnormal.

[0038] Specifically, use a knife to gently cut a 15mm distance from the edge of the PP layer of the sample, apply a little alcohol on the scratch position, wipe off the alcohol after 3 seconds, peel it off in layers, gently pull both sides of the scratch with both hands to slowly separate the PP layer and the middle PET layer by 2mm, and separate the PP layer and PET from the bonding place. Use a steel ruler to press 2mm above the pulled PP layer to prevent it from moving, and slowly pull the PET composite layer with uniform force to separate 3cm.

[0039] Specifically, the data reading range has an average tension value of D=5N.

[0040] Specifically, the PET surface is facing oneself so that the peeling state can be observed at all times to see whether there is delamination or damage, so as to judge the accuracy of the peeling force.

[0041] Specifically, the PET tab film was tested using the technical solution, and each sample was peeled off inside and outside, and the batch numbers were recorded as A, B, and C respectively. The test results of the inner and outer PP layers A inside, B inside, C inside, A outside, B outside, and C outside are shown in Table 1 below.

[0042] Table 1 Results of the inner and outer PP cross-peel test

[0043] See also Figure 2 Upper middle, such as Figure 2 As shown, A inside and A outside are intact without any breakage after the inner and outer surfaces PP are cross-peeled.

[0044] Specifically, the results obtained in this embodiment are as follows: the two PP layers can be cross-peeled on one sample, and the peeling forces on the inner and outer surfaces of samples A, B, and C are different, which can effectively prevent the wrong PP surface from being used, and the peeling state of the sample can be observed to see whether it is peeled, delaminated, or damaged.

[0045] The PET tab film was subjected to a single-sided peeling test. A single single-sided PP layer was peeled off for each sample. The batch numbers were marked as D, F, G, respectively. The test results of the inner and outer PP layers were Dinside, Finside, Ginside, Doutside, Foutside, and Goutside as shown in Table 2 below.

[0046] Table 2 Single-sided PP peel test results

[0047] See also Figure 2 Lower middle, such as Figure 2As shown in Figure 4, after single-sided PP peeling inside D, the tab film warped, and the difficulty of complete peeling was higher than the cross-peeling of the inner and outer PP.

[0048] Specifically, the results obtained in this embodiment are as follows: From the data, it can be seen that when the single-sided PP layer is peeled off, since the inner and outer PP layers are peeled off as separate samples, the peeling force will be consistent, and the inner and outer samples peeled off are not in the same position, which cannot actually reflect the data.

[0049] In summary, the cross-peeling performance test method of the PET tab film achieves the effect of obtaining the peeling force performance of the inner and outer PP layers on the same tab film sample by cross-peeling the double-sided PP layer, and uses a segmented opening to ensure the integrity of the film layer, which can reflect the most realistic performance of the PET tab film.

[0050] Based on the above ideal embodiments of the present invention, the relevant staff can make various changes and modifications without departing from the technical concept of the present invention through the above description. The technical scope of the present invention is not limited to the contents of the specification, and its technical scope must be determined according to the scope of the claims.

Claims

1. A cross-peeling performance testing method for PET tab film, characterized in that: The steps include: Step S1, cutting the PET tab film to obtain a sample, and marking the inner surface and the outer surface; Step S2, setting the outer side of the sample facing upward, lightly scratching a first shallow mark on one side between the outer PP layer and the middle PET layer of the sample, smearing the first shallow mark with a solvent, expanding the first shallow mark into a first opening, fixing the outer PP layer and pulling the middle PET layer to separate; Step S3, facing the inner surface of the sample peeled in step S2 upward, lightly scratching a second shallow mark on one side between the inner PP layer and the middle PET layer of the sample, wherein the first shallow mark and the second shallow mark are respectively located on both sides of the sample, and applying a solvent to the second shallow mark to expand the second shallow mark into a second opening, fixing the inner PP layer and pulling the middle PET layer to separate; Step S4, setting the tension parameter of the tensile testing machine to D, clamping the outer PP layer with the tensile testing machine, and obtaining the average peeling force D1 of the outer PP layer within the data reading range; Step S5, clamping the inner PP layer with a tensile testing machine to obtain an average peeling force D2 of the inner PP layer within a data reading range; Step S6, observing the delamination and damage of the sample after peeling off the two sides, and the data of the sample without damage proceeds to step S8; Step S7, respectively compare D1 and D2 with D. When both D1 and D2 are greater than D, the peeling force is normal; if either one of them is not satisfied, the peeling force is abnormal.

2. The cross-peeling performance testing method of the PET tab film according to claim 1, characterized in that: The size of the sample in step S1 is 15 mm*120 mm.

3. The cross-peeling performance testing method of the PET tab film according to claim 1, characterized in that: The depth of the first shallow mark and the second shallow mark ranges from 10 to 15 mm; The depth of the first opening and the second opening ranges from 12 to 20 mm.

4. The cross-peeling performance testing method of the PET tab film according to claim 1, characterized in that: The separation distance in steps S2 and S3 is 1-5 cm.

5. The cross-peeling performance testing method of the PET tab film according to claim 1, characterized in that: The method of fixing the outer PP layer and the inner PP layer in steps S2 and S3 includes using a steel ruler to hold them; wherein The contact angle of the steel ruler is 130-150°, and the contact width is 10-20 mm.

6. The cross-peeling performance testing method of the PET tab film according to claim 1, characterized in that: The average value of the tension parameter D in step S4 is 5N.

7. The cross-peeling performance testing method of the PET tab film according to claim 1, characterized in that: The parameters set in step S4 also include the upper and lower clamp spacing, the peeling speed, the test change point distance and the data reading range.

8. The cross-peeling performance testing method of the PET tab film according to claim 1, characterized in that: The setting range of the distance between the upper and lower clamps is 3-5 cm.

9. The cross-peeling performance testing method of the PET tab film according to claim 1, characterized in that: The peeling speed is set in the range of 50-200 mm / min.

10. The cross-peeling performance testing method of the PET tab film according to claim 1, characterized in that: The data reading range is 15-55mm; The distance between the test change point and the initial point of the tensile machine is in the range of 60-80 mm.

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