Device and method for testing tearability of composite film

Abstract

The invention discloses a device and method for testing the tearability of a composite film, the device comprises a base assembly, a first lower clamp assembly, a second lower clamp assembly and an upper clamp assembly, the first lower clamp assembly is used for clamping a first part of a sample, the second lower clamp assembly is used for clamping a second part of the sample, and the upper clamp assembly is used for clamping a second part of the sample. The sample comprises a first notch and a second notch which are parallel to each other and partially penetrate through the sample, a first part and a third part which are positioned on two sides of the first notch, and a third part and a second part which are positioned on two sides of the second notch; the first lower clamp assembly clamping the first part and the second lower clamp assembly clamping the second part are installed on the base assembly in a relative sliding mode.

Description

Technical Field

[0001] This application relates to the field of packaging film material performance testing technology, and in particular to an apparatus and method for testing the tear resistance of composite films. Background Technology

[0002] As the convenience food industry gradually moves towards healthier and more premium products, composite packaging films are increasingly used in packaging noodles, sauces, and dehydrated vegetables. Consumers using composite packaging films need to tear open the packaging through pre-set easy-tear openings to remove the contents. However, some composite packaging films have poor tear resistance, easily leading to tearing, misalignment, and spillage, which seriously affects the user experience.

[0003] Therefore, to ensure a good user experience, it is usually necessary to evaluate the tear resistance of packaging composite films. Currently, the existing methods for evaluating the tear resistance of packaging composite films mainly include tensile testing and hand tear testing. However, both tensile testing and hand tear testing have the following problems.

[0004] For example, during tensile testing (hand tear test), the clamps (hand) holding the packaging composite film are prone to skew, which may affect the test results for straight tearability. Furthermore, both tensile testing and hand tear testing lack standardized quantitative indicators to assess the "straight tearability" of the packaging composite film.

[0005] In the existing technology, there is a technical problem that the clamps of the testing device are prone to skew when holding the packaging composite film in traditional testing methods, which may affect the test results for straight tearability and reduce the accuracy of the test results. No effective solution has been proposed yet. Summary of the Invention

[0006] This disclosure provides an apparatus and method for testing the tearability of composite films, which at least solves the technical problem in the prior art where the clamps of the testing apparatus tend to deflect when holding the packaging composite film, which may affect the test results for straight tearability and result in low accuracy of the test results.

[0007] According to one aspect of this application, an apparatus for testing the tear resistance of a composite film is provided, comprising: a base assembly, a first lower clamp assembly, a second lower clamp assembly, and an upper clamp assembly, wherein the first lower clamp assembly is used to clamp a first portion of a sample, the second lower clamp assembly is used to clamp a second portion of the sample, and the upper clamp assembly is used to clamp a third portion of the sample, wherein the sample includes a first cut and a second cut that are relatively parallel and partially penetrate the sample, a first portion and a third portion located on both sides of the first cut, and a third portion and a second portion located on both sides of the second cut; and the first lower clamp assembly holding the first portion and the second lower clamp assembly holding the second portion are slidably mounted on the base assembly.

[0008] Optionally, the first lower clamp assembly includes: a first lower clamp and a first jaw disposed on the first lower clamp, wherein the first jaw is used to clamp a first portion of the sample.

[0009] Optionally, the second lower clamp assembly includes: a second lower clamp and a second jaw disposed on the second lower clamp, wherein the second jaw is used to clamp a second portion of the sample.

[0010] Optionally, the upper clamp assembly includes an upper clamp and a third jaw disposed on the upper clamp, wherein the third jaw is used to clamp a third portion of the sample.

[0011] Optionally, rubber sheets are provided on the inner walls of the first jaw, the second jaw, and the third jaw.

[0012] Optionally, the base assembly includes: a base and a guide rail fixedly mounted on the base, wherein the guide rail includes a sliding groove, a first lower clamp is fixedly connected to a first screw, a second lower clamp is fixedly connected to a second screw, and the first lower clamp is slidably connected to the sliding groove via the first screw, and the second lower clamp is slidably connected to the sliding groove via the second screw.

[0013] According to another aspect of this application, a method for testing the tear resistance of a composite film is provided, comprising: determining a specimen for tear resistance testing, wherein the specimen includes a first cut and a second cut arranged in parallel, a first portion and a third portion located on both sides of the first cut, and a third portion and a second portion located on both sides of the second cut, wherein the first cut and the second cut portions penetrate the specimen; determining a first lower clamp assembly and a second lower clamp assembly slidably mounted on a base assembly, and clamping the first portion with the first lower clamp assembly and the second portion with the second lower clamp assembly; determining an upper clamp assembly and clamping the third portion with the upper clamp assembly; and relatively slidingly clamping the first lower clamp assembly holding the first portion and the second lower clamp assembly holding the second portion, and performing a tear resistance test on the specimen.

[0014] Optionally, the operation of performing a tear test on the specimen by relative sliding clamps holding a first lower clamp assembly of the first portion and a second lower clamp assembly of the second portion includes: determining a first tear corresponding to the extension direction of the first cut and a second tear corresponding to the extension direction of the second cut after the test, and determining a tear portion located between the first tear and the second tear; measuring a first width value at the narrowest point of the tear portion; measuring a second width value of the second portion; and evaluating the tearability of the specimen based on the first width value and the second width value.

[0015] Optionally, the operation of evaluating the tearability of the specimen based on the first width value and the second width value includes: calculating the linear tear offset index of the specimen based on the first width value and the second width value using the following formula, the specific formula of which is as follows: in, This indicates the linear tear offset index of the specimen. This represents the second width value. The first width value is indicated; and the linear tearability of the specimen is evaluated based on the calculated linear tear offset index.

[0016] Optionally, the operation of evaluating the linear tearability of the sample based on the calculated linear tear offset index includes: determining a pre-set first threshold and a second threshold, and indicating that the sample has good linear tearability when the linear tear offset index is less than or equal to the first threshold; indicating that the sample has average linear tearability when the linear tear offset index is greater than the first threshold and less than or equal to the second threshold; and indicating that the sample has poor linear tearability when the linear tear offset index is greater than the second threshold.

[0017] This application provides a device for testing the tear resistance of composite films. Referring to the above description, the testing device includes a base assembly, a first lower clamp assembly and a second lower clamp assembly slidably disposed on the base assembly. The sample is pre-cut before testing. The cut sample includes a first cut and a second cut partially penetrating the sample, a first portion and a third portion on the left and right sides of the first cut, and a third portion and a second portion on the left and right sides of the second cut. Notably, the first cut and the second cut are parallel to each other.

[0018] Therefore, since this application uses a first lower clamp assembly to clamp the first part of the sample separately, and a second lower clamp assembly to clamp the second part of the sample separately, it can ensure that the axis of the first part of the sample coincides with the center of the line connecting the first lower clamp assembly, and it can also ensure that the axis of the second part of the sample coincides with the center of the line connecting the second lower clamp assembly. In other words, for each part of the sample (i.e., the first part, the second part, and the third part), it can ensure that its central axis coincides with the axis of the corresponding clamp.

[0019] Furthermore, during testing, the positions of the first and second lower clamping assemblies on the base assembly can be adjusted by relative sliding clamps holding the first lower clamping assembly of the first part and the second lower clamping assembly of the second part. In other words, for the entire sample, it can be ensured that the central axis of the entire sample coincides with the axis of the testing device.

[0020] Therefore, by adjusting the positions of the first, second, and third parts of the sample on their respective fixtures, as well as the positions of each fixture on the base assembly, it can be ensured that the entire sample and each part of the sample are flat, wrinkle-free, and vertically fixed on the fixtures of the testing device, eliminating measurement errors caused by wrinkles or skewing of the test sample. This solves the technical problem in existing technologies where, in traditional testing methods, the fixtures of the testing device are prone to skewing when holding the packaging composite film, which may affect the test results for straight tear resistance and result in low accuracy.

[0021] The above and other objects, advantages and features of this application will become more apparent to those skilled in the art from the following detailed description of specific embodiments of this application in conjunction with the accompanying drawings. Attached Figure Description

[0022] The following sections will describe some specific embodiments of this application in detail by way of example and not limitation, with reference to the accompanying drawings. The same reference numerals in the drawings denote the same or similar parts or components. Those skilled in the art should understand that these drawings are not necessarily drawn to scale. In the drawings: Figure 1 This is a front view of the apparatus for testing the tear resistance of composite films according to Embodiment 1 of this application; Figure 2 This is a right view of the composite tear resistance testing apparatus according to Embodiment 1 of this application; Figure 3 This is a left view of the composite tear resistance testing apparatus according to Embodiment 1 of this application; Figure 4 This is a schematic diagram of the sample according to Embodiment 1 of this application; Figure 5This is a flowchart of a method for testing the tear resistance of a composite membrane according to Embodiment 2 of this application. Detailed Implementation

[0023] It should be noted that, unless otherwise specified, the embodiments and features described in this disclosure can be combined with each other. This disclosure will now be described in detail with reference to the accompanying drawings and embodiments.

[0024] To enable those skilled in the art to better understand the present disclosure, the technical solutions of the present disclosure will be clearly and completely described below with reference to the accompanying drawings of the embodiments. Obviously, the described embodiments are only some embodiments of the present disclosure, and not all embodiments. Based on the embodiments of the present disclosure, all other embodiments obtained by those skilled in the art without creative effort should fall within the scope of protection of the present disclosure.

[0025] It should be noted that the terms "first," "second," etc., in the specification, claims, and accompanying drawings of this disclosure are used to distinguish similar objects and are not necessarily used to describe a specific order or sequence. It should be understood that such terms can be used interchangeably where appropriate for the embodiments of this disclosure described herein. Furthermore, the terms "comprising" and "having," and any variations thereof, are intended to cover non-exclusive inclusion; for example, a process, method, system, product, or apparatus that comprises a series of steps or units is not necessarily limited to those steps or units explicitly listed, but may include other steps or units not explicitly listed or inherent to such processes, methods, products, or apparatus.

[0026] It should be noted that the terminology used herein is for the purpose of describing particular embodiments only and is not intended to limit the exemplary embodiments according to this application. As used herein, the singular form is intended to include the plural form as well, unless the context clearly indicates otherwise. Furthermore, it should be understood that when the terms "comprising" and / or "including" are used in this specification, they indicate the presence of features, steps, operations, devices, components, and / or combinations thereof.

[0027] Figure 1 This is a front view of the apparatus for testing the tear resistance of composite films according to Embodiment 1 of this application. Figure 2 This is a right view of the composite tearing test apparatus according to Embodiment 1 of this application. Figure 3 This is a left view of the composite tearing test apparatus according to Embodiment 1 of this application. Figure 4 This is a schematic diagram of the sample according to Embodiment 1 of this application. (Reference) Figure 1 , Figure 2 , Figure 3 as well as Figure 4As shown, a device for testing the tear resistance of a composite film includes: a base assembly 10, a first lower clamp assembly 20, a second lower clamp assembly 30, and an upper clamp assembly 40. The first lower clamp assembly 20 is used to clamp a first portion 510 of a sample 50, the second lower clamp assembly 30 is used to clamp a second portion 520 of the sample 50, and the upper clamp assembly 40 is used to clamp a third portion 530 of the sample 50. The sample 50 includes a first cut 540 and a second cut 550 that are relatively parallel and partially penetrate the sample. The first portion 510 and the third portion 530 are located on both sides of the first cut 540, and the third portion 530 and the second portion 520 are located on both sides of the second cut 550. The first lower clamp assembly 20 holding the first portion 510 and the second lower clamp assembly 30 holding the second portion 520 are slidably mounted on the base assembly 10.

[0028] As described in the background section, to ensure a good user experience, it is often necessary to evaluate the tear performance of packaging composite films. Currently, existing methods for evaluating the tear performance of packaging composite films mainly include tensile testing and hand tear testing. However, both methods have the following problems. For example, during tensile testing (hand tear testing), the clamps (hand) holding the packaging composite film are prone to skew, which may affect the test results for straight tearability. Furthermore, both tensile testing and hand tear testing lack a unified quantitative index to evaluate the "straight tearability" of the packaging composite film. That is, existing technologies suffer from uneven sample tension or curling, which can cause the sample to become skewed, resulting in an inclined cut position before the test begins, and the tear propagation direction deviating from the preset cut direction at the start of the test.

[0029] To address the aforementioned problems, this application provides an apparatus for testing the tear resistance of composite films. This apparatus is used to perform tear resistance testing on a sample 50 made of a composite film. (Reference) Figure 4 As shown, before conducting a tear test on the specimen 50, the specimen 50 needs to be pre-cut using a cutting die. Thus, the cut specimen 50 includes a first cut 540 and a second cut 550 that are parallel to each other and partially penetrate the specimen 50, a first portion 510 and a third portion 530 located on both sides of the first cut 540, and a third portion 530 and a second portion 520 located on both sides of the second cut 550.

[0030] Furthermore, in this embodiment, by Figure 4It is known that the width of the third part 530 of the sample 50 is greater than the width of the first part 510 and the width of the second part 520 of the sample 50. However, those skilled in the art should understand that the actual situation is not limited to this.

[0031] Thus, after the specimen 50 has been cut, the third part 530 of the specimen is clamped by the upper clamping assembly 40. Then, the first part 510 of the specimen 50 is clamped by the first lower clamping assembly 20, and the second part 520 of the specimen 50 is clamped by the second lower clamping assembly 30.

[0032] Since the first lower clamp assembly 20 clamps the first part 510 of the sample 50 separately, if the central axis of the first part 510 does not coincide with the center of the line connecting the first lower clamp assembly 20 during the test (i.e., the first part 510 is tilted on the first lower clamp assembly 20), the position of the first part 510 of the sample 50 on the first lower clamp assembly 20 can be adjusted to ensure that the first part 510 of the sample 50 is clamped vertically and flatly on the first lower clamp assembly 20.

[0033] Similarly, since the second lower clamp assembly 30 clamps the second part 520 of the sample 50 separately, if the central axis of the second part 520 does not coincide with the center of the line connecting the second lower clamp assembly 30 during the test (i.e., the second part 520 is tilted on the second lower clamp assembly 30), the position of the second part 520 of the sample 50 on the second lower clamp assembly 30 can be adjusted to ensure that the second part 520 of the sample 50 is clamped vertically and flatly on the second lower clamp assembly 30.

[0034] Similarly, since the upper clamp assembly 40 clamps the third part 530 of the sample 50 separately, if the central axis of the third part 530 does not coincide with the center of the line connecting the upper clamp assembly 40 during the test (i.e., the third part 530 is tilted on the upper clamp assembly 40), the position of the third part 530 of the sample 50 on the upper clamp assembly 40 can be adjusted to ensure that the third part 530 of the sample 50 is clamped vertically and flatly on the upper clamp assembly 40.

[0035] In other words, for each part of the sample 50 (i.e., the first part 510, the second part 520, and the third part 530), it can be ensured that its central axis coincides with the axis of the corresponding fixture.

[0036] Furthermore, since the first lower clamp assembly 20 and the second lower clamp assembly 30 in this application can slide relative to each other on the base assembly 10, if the first part 510 and the second part 520 of the sample 50 have wrinkles or skewing due to the positional relationship between the first lower clamp assembly 20 and the second lower clamp assembly 30, the position of the first lower clamp assembly 20 and the second lower clamp assembly 30 on the base assembly 10 can be adjusted to ensure that the sample 50 is wrinkle-free and flat.

[0037] In other words, for the sample 50 as a whole, it can be ensured that the central axis of the whole sample 50 coincides with the axis of the testing device.

[0038] Thus, with the sample kept flat, wrinkle-free and vertically fixed on the testing device, the sample 50 can be torn and tested by sliding the first lower clamp assembly 20 holding the first part 510 of the sample 50 and the second lower clamp assembly 30 holding the second part 520 of the sample 50.

[0039] Therefore, by adjusting the positions of the first part 510, the second part 520, and the third part 530 of the sample 50 on their respective fixtures, and the positions of each fixture on the base assembly 10, it can be ensured that the entire sample 50 and each part of the sample 50 are flat, wrinkle-free, and vertically fixed on the fixtures of the testing device, eliminating measurement errors caused by wrinkles or skewing of the test sample. This solves the technical problem in existing traditional testing methods where the fixtures of the testing device are prone to skewing when holding the packaging composite film, which may affect the test results for straight tear resistance and result in low accuracy.

[0040] Optionally, the first lower clamp assembly 20 includes: a first lower clamp 210 and a first jaw 220 disposed on the first lower clamp 210, wherein the first jaw 220 is used to clamp the first portion 510 of the sample 50.

[0041] Specifically, refer to Figure 1 , Figure 2 and Figure 3 As shown, the first lower clamp assembly 20 includes a first lower clamp 210 and a first jaw 220. The first lower clamp 210 is slidably disposed on the base assembly 10, and the first jaw 220 is fixedly disposed on the first lower clamp 210. The first jaw 220 is used to clamp and release the first portion 510 of the sample 50.

[0042] Therefore, by using the first jaws 220 to release or clamp the first portion 510 of the sample 50, the position of the first portion 510 of the sample 50 on the first jaws 220 can be adjusted. This ensures that the central axis of the first portion 510 of the sample 50 coincides with the axis of the first lower clamp 210, thereby ensuring that the first portion 510 of the sample 50 is free from offset and wrinkles, and improving the accuracy of the test results.

[0043] Optionally, the second lower clamp assembly 30 includes a second lower clamp 310 and a second jaw 320 disposed on the second lower clamp 310, wherein the second jaw 320 is used to clamp the second portion 520 of the sample 50.

[0044] Specifically, refer to Figure 1 , Figure 2 and Figure 3 As shown, the second lower clamp assembly 30 includes a second lower clamp 310 and a second jaw 320. The second lower clamp 310 is slidably disposed on the base assembly 10, and the second jaw 320 is fixedly disposed on the second lower clamp 310. The second jaw 320 is used to clamp and release the second part 520 of the sample 50.

[0045] Therefore, by using the second jaw 320 to release or clamp the second part 520 of the sample 50, the position of the second part 520 of the sample 50 on the second jaw 320 can be adjusted. This ensures that the central axis of the second part 520 of the sample 50 coincides with the axis of the second lower clamp 310, thereby ensuring that the second part 520 of the sample 50 is free from offset and wrinkles, and improving the accuracy of the test results.

[0046] Optionally, the upper clamp assembly 40 includes an upper clamp 410 and a third jaw 420 disposed on the upper clamp 410, wherein the third jaw 420 is used to clamp the third portion 530 of the sample 50.

[0047] Specifically, refer to Figure 1 , Figure 2 and Figure 3 As shown, the upper clamp assembly 40 includes an upper clamp 410 and a third jaw 420. The upper clamp 410 is slidably disposed on the base assembly 10, and the third jaw 420 is fixedly disposed on the upper clamp 410. The third jaw 420 is used to clamp and release the third part 530 of the sample 50.

[0048] Therefore, by using the third jaw 420 to release or clamp the third part 530 of the sample 50, the position of the third part 530 of the sample 50 on the third jaw 420 can be adjusted. This ensures that the central axis of the third part 530 of the sample 50 coincides with the axis of the upper clamp 410, thereby ensuring that the third part 530 of the sample 50 is free from offset and wrinkles, and improving the accuracy of the test results.

[0049] Optionally, rubber sheets are provided on the inner walls of the first jaw 220, the second jaw 320, and the third jaw 420. That is, rubber sheets are provided on the side of the first jaw 220, the second jaw 320, and the third jaw 420 that contacts the sample 50, mainly to enhance the stability of the clamping of the first jaw 220, the second jaw 320, and the third jaw 420.

[0050] Optionally, the base assembly 10 includes: a base 110 and a guide rail 120 fixedly disposed on the base 110, wherein the guide rail 120 includes a sliding groove 121, a first lower clamp 210 is fixedly connected to a first screw 130, a second lower clamp 310 is fixedly connected to a second screw 140, and the first lower clamp 210 is slidably connected to the sliding groove 121 through the first screw 130, and the second lower clamp 310 is slidably connected to the sliding groove 121 through the second screw 140.

[0051] Specifically, refer to Figure 1 , Figure 2 and Figure 3 As shown, the base assembly 10 includes a base 110 and a guide rail 120 disposed on the base 110. The guide rail 120 is also provided with a sliding groove 121, so that the first lower clamp 210 is slidably connected to the sliding groove 121 by the first screw 130, and the second lower clamp 310 is connected to the sliding groove 121 by the second screw 140.

[0052] Thus, when the first jaw 220 on the first lower clamp 210 clamps the first portion 510 of the sample 50, and the second jaw 320 on the second lower clamp 310 clamps the second portion 520 of the sample 50, the positions of the first portion 510 and the second portion 520 can be adjusted by moving the first lower clamp 210 and the second lower clamp 310 located on the guide rail 120. This ensures that the axis of the sample 50 coincides with the center line of the axis of the testing device.

[0053] According to another aspect of this application, a method for testing the tear resistance of composite films is also provided. Figure 5 This is a flowchart of a method for testing the tear resistance of a composite film according to Embodiment 2 of this application. (See reference) Figure 5 As shown, it includes: S502: Determine a specimen for tear testing, wherein the specimen includes a first and a second cut that are relatively parallel and partially penetrate the specimen, a first portion and a third portion located on either side of the first cut, and a third portion and a second portion located on either side of the second cut. S504: Determine a first lower clamping assembly and a second lower clamping assembly that are slidably mounted on the base assembly, and clamp the first part using the first lower clamping assembly and the second part using the second lower clamping assembly; S506: Determine the upper clamping assembly and use the upper clamping assembly to clamp the third part; and S508: The relative sliding clamp holds the first lower clamp assembly of the first part and the second lower clamp assembly of the second part, and performs a tear test on the specimen.

[0054] Specifically, firstly, the operator uses a cutting mold to cut the sample, resulting in a sample comprising a first part, a second part, and a third part (S502). The first cut between the first and third parts, and the second cut between the second and third parts, are parallel to each other and partially penetrate the sample.

[0055] Then, the operator fixes the first lower clamp assembly, the second lower clamp assembly, and the upper clamp assembly onto the universal tensile testing machine, and adjusts the distance between the upper clamp assembly and the lower clamp assembly (including the first lower clamp assembly and the second lower clamp assembly).

[0056] The operator then clamps the first part of the sample onto the first lower clamping assembly and the second part of the sample onto the second lower clamping assembly (S504).

[0057] Furthermore, the operator clamps the third part of the sample onto the upper clamping assembly (S506). The operator then adjusts the relative positions of the first lower clamping assembly holding the first part of the sample and the second lower clamping assembly holding the second part of the sample on the base assembly. This ensures the sample is fixed flat, wrinkle-free, and vertically onto the corresponding clamping assemblies, eliminating testing errors caused by wrinkles or skewing of the sample.

[0058] Finally, the operator moves the first lower clamp assembly of the first part and the second lower clamp assembly of the second part by moving the clamp, and performs a tear test on the sample (S508). The above will be described in detail later, and therefore will not be repeated here.

[0059] Therefore, by adjusting the positions of the first, second, and third parts of the sample on their respective fixtures, as well as the positions of each fixture on the base assembly, it can be ensured that the entire sample and each part of the sample are flat, wrinkle-free, and vertically fixed on the fixtures of the testing device, eliminating measurement errors caused by wrinkles or skewing of the test sample. This solves the technical problem in existing technologies where, in traditional testing methods, the fixtures of the testing device are prone to skewing when holding the packaging composite film, which may affect the test results for straight tear resistance and result in low accuracy.

[0060] Optionally, the operation of performing a tear test on the specimen by relative sliding clamps holding a first lower clamp assembly of the first portion and a second lower clamp assembly of the second portion includes: determining a first tear corresponding to the extension direction of the first cut and a second tear corresponding to the extension direction of the second cut after the test, and determining the tear portion located between the first tear and the second tear; measuring a first width value at the narrowest point of the tear portion; measuring a second width value of the second portion; and evaluating the tearability of the specimen based on the first width value and the second width value. Further optionally, the operation of evaluating the tearability of the specimen based on the first width value and the second width value includes: calculating the linear tear offset index of the specimen based on the first width value and the second width value using the following formula, the specific formula being as follows: in, This indicates the linear tear offset index of the specimen. This represents the second width value. The first width value is represented; and the linear tearability of the specimen is evaluated based on the calculated linear tear offset index. Further optionally, the operation of evaluating the linear tearability of the specimen based on the calculated linear tear offset index includes: determining a pre-set first threshold and a second threshold, and indicating that the specimen has good linear tearability if the linear tear offset index is less than or equal to the first threshold; indicating that the specimen has moderate linear tearability if the linear tear offset index is greater than the first threshold and less than or equal to the second threshold; and indicating that the specimen has poor linear tearability if the linear tear offset index is greater than the second threshold.

[0061] Specifically, when a first lower clamping assembly holds a first portion of the sample in a sliding clamp, and a second lower clamping assembly holds a second portion of the sample, a first tear appears along the extension direction of the first cut, and a second tear appears along the extension direction of the second cut. Thus, a tear portion appears between the first tear and the second tear.

[0062] The operator can then use the scales pre-set on the first and second lower clamping assemblies to determine the first width value at the narrowest point of the tear. And the second width value of the second part .

[0063] The linear tear resistance of the specimen can then be evaluated using the following formula. The following formula is primarily used to calculate the linear tear offset index of the specimen, and the specific formula is as follows: in, This indicates the linear tear offset index of the specimen. This represents the second width value. This represents the first width value.

[0064] Therefore, after calculating the linear tear offset index corresponding to the tested sample, the linear tear offset index can be used to determine whether the sample has good linear tearability based on its relationship with a pre-set first threshold and a second threshold. The first and second thresholds can be determined by the operator based on historical experience or data, and are not limited here.

[0065] For example, the first threshold could be 15%, and the second threshold could be 25%. And... A concentration of ≤15% indicates good straight-line tear resistance of the sample. A concentration of <15% indicates good tear resistance. A value ≤25% indicates that the straight-line tearability of the sample is average. If the percentage is greater than 25%, it indicates poor straight-line tearability of the sample.

[0066] As can be seen from the above, this application can rely on the existing universal tensile testing machine without the need for additional investment in new equipment. The testing method is simple and the investment cost is low.

[0067] Furthermore, this application also provides a rating method that can determine the tear performance and straight-line tearability of composite films, thereby quantifying the tearability of composite films.

[0068] Unless otherwise specifically stated, the relative arrangement, numerical expressions, and values ​​of the components and steps set forth in these embodiments do not limit the scope of this disclosure. It should also be understood that, for ease of description, the dimensions of the various parts shown in the drawings are not drawn to actual scale. Techniques, methods, and devices known to those skilled in the art may not be discussed in detail, but where appropriate, such techniques, methods, and devices should be considered part of the specification. In all examples shown and discussed herein, any specific values ​​should be interpreted as merely exemplary and not as limitations. Therefore, other examples of exemplary embodiments may have different values. It should be noted that similar reference numerals and letters in the following drawings denote similar items; therefore, once an item is defined in one drawing, it need not be further discussed in subsequent drawings.

[0069] For ease of description, spatial relative terms such as "above," "on top of," "on the upper surface of," "above," etc., are used herein to describe the spatial positional relationship of a device or feature as shown in the figures to other devices or features. It should be understood that spatial relative terms are intended to encompass different orientations in use or operation beyond the orientation of the device as described in the figures. For example, if the device in the figures were inverted, a device described as "above" or "on top of" other devices or structures would subsequently be positioned as "below" or "under" other devices or structures. Thus, the exemplary term "above" can include both "above" and "below." The device may also be positioned in other different ways (rotated 90 degrees or in other orientations), and the spatial relative descriptions used herein will be interpreted accordingly.

[0070] In the description of this disclosure, it should be understood that the orientation or positional relationship indicated by directional terms such as "front, back, up, down, left, right", "horizontal, vertical, horizontal" and "top, bottom" is generally based on the orientation or positional relationship shown in the accompanying drawings and is only for the convenience of describing this disclosure and simplifying the description. Unless otherwise stated, these directional terms do not indicate or imply that the device or element referred to must have a specific orientation or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation on the scope of protection of this disclosure; the directional terms "inner" and "outer" refer to the inner and outer contours relative to the outline of each component itself.

[0071] The above description is merely a preferred embodiment of this application, but the scope of protection of this application is not limited thereto. Any variations or substitutions that can be easily conceived by those skilled in the art within the technical scope disclosed in this application should be included within the scope of protection of this application. Therefore, the scope of protection of this application should be determined by the scope of the claims.

Claims

1. An apparatus for testing the tear resistance of a composite film, characterized by include: The base assembly (10), the first lower clamp assembly (20), the second lower clamp assembly (30), and the upper clamp assembly (40), wherein The first lower clamp assembly (20) is used to clamp a first portion (510) of the specimen (50), the second lower clamp assembly (30) is used to clamp a second portion (520) of the specimen (50), and the upper clamp assembly (40) is used to clamp a third portion (530) of the specimen (50), wherein The sample (50) is made of a composite film, and the sample includes a first cut (540) and a second cut (550) that are parallel to each other and partially penetrate the sample, a first portion (510) and a third portion (530) located on both sides of the first cut (540), and a third portion (530) and a second portion (520) located on both sides of the second cut (550); and A first lower clamp assembly (20) holding the first portion (510) and a second lower clamp assembly (30) holding the second portion (520) are slidably mounted on the base assembly (10).

2. The apparatus for testing the tearability of a composite film according to claim 1, wherein The first lower clamp assembly (20) includes: a first lower clamp (210) and a first jaw (220) disposed on the first lower clamp (210), wherein the first jaw (220) is used to clamp a first portion (510) of the sample (50).

3. The apparatus according to claim 2, wherein The second lower clamp assembly (30) includes a second lower clamp (310) and a second jaw (320) disposed on the second lower clamp (310), wherein the second jaw (320) is used to clamp a second portion (520) of the sample (50).

4. The apparatus according to claim 3, wherein The upper clamp assembly (40) includes an upper clamp (410) and a third jaw (420) disposed on the upper clamp (410), wherein the third jaw (420) is used to clamp a third portion (530) of the sample (50).

5. The apparatus according to claim 4, wherein The inner walls of the first jaw (220), the second jaw (320) and the third jaw (420) are provided with rubber sheets.

6. The apparatus for testing the tearability of a composite film according to claim 3, wherein The base assembly (10) includes: a base (110) and a guide rail (120) fixedly disposed on the base (110), wherein The guide rail (120) includes a sliding groove (121), the first lower clamp (210) is fixedly connected to a first screw (130), and the second lower clamp (310) is fixedly connected to a second screw (140). The first lower clamp (210) is slidably connected to the sliding groove (121) by the first screw (130), and the second lower clamp (310) is slidably connected to the sliding groove (121) by the second screw (140).

7. A method for testing the tear resistance of a composite film, characterized by, include: A specimen for tear testing is determined, wherein the specimen is made of a composite film and the specimen includes a first cut and a second cut that are relatively parallel and partially penetrate the specimen, a first portion and a third portion located on both sides of the first cut, and a third portion and a second portion located on both sides of the second cut. determining a first lower clamp assembly and a second lower clamp assembly slidably mounted to the base assembly, and clamping the first portion with the first lower clamp assembly and clamping the second portion with the second lower clamp assembly; determining an upper clamp assembly, and clamping the third portion with the upper clamp assembly; and slidably clamping the first lower clamp assembly holding the first portion and the second lower clamp assembly holding the second portion, and performing a tear test on the test sample.

8. The method of claim 7, wherein, The operation of slidably clamping the first lower clamp assembly holding the first portion and the second lower clamp assembly holding the second portion, and performing a tear test on the test sample, includes: determining a first tear opening corresponding to an extension direction of the first cut and a second tear opening corresponding to an extension direction of the second cut after the test ends, and determining a tear portion between the first tear opening and the second tear opening; measuring a first width value of a narrowest portion of the tear portion; measuring a second width value of the second portion; and evaluating a tear property of the test sample based on the first width value and the second width value.

9. The method of claim 8, wherein, The operation of evaluating a tear property of the test sample based on the first width value and the second width value, includes: calculating a straight-line tear shift index of the test sample based on the first width value and the second width value, using the following formula: wherein, represents a straight line tear offset index of the sample, represents the second width value, represents the first width value; and evaluating a straight-line tearability of the test sample according to the calculated straight-line tear shift index.

10. The method of claim 9, wherein, The operation of evaluating a straight-line tearability of the test sample according to the calculated straight-line tear shift index, includes: determining a first threshold value and a second threshold value in advance, and in a case where the straight-line tear shift index is less than or equal to the first threshold value, indicating that the straight-line tearability of the test sample is good; in a case where the straight-line tear shift index is greater than the first threshold value and less than or equal to the second threshold value, indicating that the straight-line tearability of the test sample is general; and in a case where the straight-line tear shift index is greater than the second threshold value, indicating that the straight-line tearability of the test sample is poor.

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