A method for detecting bubbles in an acoustic adhesive film

Abstract

The application relates to a bubble detection method of an acoustic adhesive film, which comprises the following steps: providing a first acoustic adhesive film and a second acoustic adhesive film; placing the first acoustic adhesive film in a solution at a first temperature for a first time length; placing the second acoustic adhesive film at the first temperature for the first time length; then baking the first acoustic adhesive film and the second acoustic adhesive film at a second temperature for a second time length; cooling the first acoustic adhesive film and the second acoustic adhesive film to a third temperature respectively; judging whether bubbles exist in the acoustic adhesive film; if bubbles exist, then aging the first acoustic adhesive film and the second acoustic adhesive film for a third time length; and repeating the above steps until no bubbles exist in the first acoustic adhesive film and the second acoustic adhesive film. The method can quickly and repeatedly detect acoustic adhesive film samples, and can detect bubbles before mass production of the acoustic adhesive film, judge whether solvent residues exist in the adhesive layer or whether solidification is complete, count the aging time of the samples, ensure the quality of the material before use, and avoid the generation of a large number of defective products in the subsequent process.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of film material detection, in particular to a bubble detection method of acoustic adhesive film. BACKGROUND

[0002] With the continuous innovation of loudspeakers, great breakthroughs have been made in the preparation technology of damping glue used by loudspeakers. In order to facilitate industrial application, the method of laminating film material with adhesive film is now commonly used to prepare loudspeaker diaphragms, but how to accurately determine the curing degree and stability of the adhesive film is still a problem to be solved. In practical applications, it is mostly relied on gluing experience to set a certain curing period, and it is assumed that the glue layer has been completely cured at the end of the curing period. However, due to changes in seasons and temperature, the curing period of the adhesive film is not fixed. If the adhesive film is directly used to compound the film material to make a composite film product before the adhesive film is completely cured, bubbles will more or less appear during the process of hot pressing. The generation of bubbles will seriously affect the use of the composite film product. If the adhesive film is not detected and determined whether the glue layer has solvent residue or incomplete curing before mass production of the adhesive film, a large number of defective products will be produced. Moreover, the bubbles generated due to solvent residue or incomplete curing are generally difficult to release through the film material, resulting in a waste of a large amount of manpower and resources. SUMMARY

[0003] The present application provides a bubble detection method of acoustic adhesive film, which can quickly and repeatedly detect samples. The method detects bubbles of the adhesive film before mass production of the adhesive film and determines whether the glue layer has solvent residue or whether the curing is complete, thereby ensuring the quality of the material before use, avoiding the generation of a large number of defective products in the downstream process, and greatly improving the production efficiency.

[0004] To solve the above technical problems, the present application provides the following technical solutions:

[0005] In a first aspect, the present application provides a bubble detection method of acoustic adhesive film, which comprises:

[0006] Step S1: providing a first acoustic adhesive film and a second acoustic adhesive film;

[0007] Step S2: soaking the first acoustic adhesive film in a solution for a first time length, wherein the solution is at a first temperature;

[0008] Step S3: placing the second acoustic adhesive film at the first temperature for the first time length;

[0009] Step S4: baking the first acoustic adhesive film and the second acoustic adhesive film at a second temperature for a second time length;

[0010] Step S5: Cool the first acoustic film and the second acoustic film to a third temperature respectively;

[0011] Step S6: Determine whether there are air bubbles in the first acoustic film and the second acoustic film;

[0012] Step S7: If air bubbles are present in the first acoustic film and / or the second acoustic film, then the first acoustic film and the second acoustic film are aged for a third time.

[0013] Step S8: Repeat steps S1 to S7 for the first and second acoustic films that have been cured for a third time until there are no air bubbles in the first and second acoustic films.

[0014] In some embodiments, the method further includes counting the number of third duration cycles and calculating the total curing time of the first acoustic film and the second acoustic film.

[0015] In some embodiments, the first temperature is 20°C to 30°C, and the first duration is 20 min to 40 min.

[0016] In some embodiments, the second temperature is 170°C to 180°C, and the second duration is 5 min to 10 min.

[0017] In some embodiments, the step of baking the first acoustic film and the second acoustic film at a second temperature for a second time includes: placing pressure blocks on the first acoustic film and the second acoustic film respectively at a second temperature, and baking the first acoustic film and the second acoustic film for a second time.

[0018] In some embodiments, the mass of the compressed block is 1500g to 2500g.

[0019] In some embodiments, both the first acoustic diaphragm and the second acoustic diaphragm include a light release layer, an acoustic damping adhesive layer, and a heavy release diaphragm; the acoustic damping adhesive layer is stacked between the light release layer and the heavy release diaphragm.

[0020] In some embodiments, the bubbles are observed using a microscope.

[0021] In some embodiments, the third duration is 3h to 5h.

[0022] In some embodiments, the third temperature is 20°C to 25°C.

[0023] The beneficial effects of the embodiments of this application are as follows: Unlike related technologies, the embodiments of this application provide a method for detecting air bubbles in an acoustic film. The method includes the following steps: S1: providing a first acoustic film and a second acoustic film; S2: immersing the first acoustic film in a solution at a first temperature for a first duration; S3: placing the second acoustic film at the first temperature for the first duration; S4: baking the first and second acoustic films at a second temperature for a second duration; S5: cooling the first and second acoustic films to a third temperature; S6: determining whether air bubbles exist in the first and second acoustic films; S7: if air bubbles exist in the first and / or second acoustic films, aging the first and second acoustic films for a third duration; S8: repeating steps S1 to S7 until no air bubbles are present in the first and second acoustic films. This method can quickly and repeatedly test samples, and before mass production of adhesive films, it can detect bubbles in the adhesive film and determine whether there is solvent residue or whether the curing is complete. It can also calculate the curing time required for the samples, ensuring the quality of the materials before use, avoiding the generation of large quantities of defective products in the downstream processes, and greatly improving production efficiency. Attached Figure Description

[0024] One or more embodiments are illustrated by way of example with reference to the accompanying drawings. These illustrations do not constitute a limitation on the embodiments. Elements having the same reference numerals in the drawings are denoted as similar elements. Unless otherwise stated, the figures in the drawings are not to be limited by scale.

[0025] Figure 1 This is a flowchart of a bubble detection method for an acoustic film provided in an embodiment of this application;

[0026] Figure 2 This is a schematic diagram of the structure of an acoustic diaphragm provided in an embodiment of this application;

[0027] Figure 3 This is a schematic diagram illustrating a scenario where an acoustic film is placed in a container, as provided in an embodiment of this application.

[0028] Figure 4 This is a schematic diagram of the air bubbles in the acoustic film of Embodiment 1 of this application;

[0029] Figure 5 This is a schematic diagram of air bubbles in the acoustic film of Comparative Example 1 of this application;

[0030] Figure 6 This is a schematic diagram of the air bubbles in the acoustic film of Comparative Example 2 of this application. Detailed Implementation

[0031] To make the objectives, technical solutions, and advantages of this application clearer, the following detailed description is provided in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative and not intended to limit the scope of this application.

[0032] It should be noted that, unless otherwise specified, the various features in the embodiments of this application can be combined with each other, all of which are within the protection scope of this application. Furthermore, although functional modules are divided in the device schematic diagram and a logical order is shown in the flowchart, in some cases, the steps shown or described may be performed in a different order than the module division in the device schematic diagram or the order in the flowchart.

[0033] Unless otherwise defined, all technical and scientific terms used in this specification have the same meaning as commonly understood by one of ordinary skill in the art to which this application belongs. The terminology used in this specification is for the purpose of describing particular embodiments only and is not intended to limit the scope of this application. The term "and / or" as used in this specification includes any and all combinations of one or more of the associated listed items.

[0034] Please see Figure 1 , Figure 1 This is a flowchart of a bubble detection method for an acoustic adhesive film provided in an embodiment of this application. The method includes:

[0035] Step S1: Provide the first acoustic diaphragm and the second acoustic diaphragm.

[0036] In some embodiments, both the first acoustic diaphragm and the second acoustic diaphragm include a light release layer, an acoustic damping adhesive layer, and a heavy release diaphragm; the acoustic damping adhesive layer is stacked between the light release layer and the heavy release diaphragm.

[0037] Specifically, please refer to Figure 2 , Figure 2This is a schematic diagram of the structure of an acoustic diaphragm provided in an embodiment of this application. The acoustic diaphragm includes a light release layer 20, an acoustic damping adhesive layer 30, and a heavy release film 40. The acoustic damping adhesive layer 30 is stacked between the light release layer 20 and the heavy release film 40. The thickness of the light release layer 20 is between 10 μm and 40 μm. The light release layer 20 is a light release silicone oil release film with self-antistatic effect, and the release force of the light release layer is 1. The release force of the light release layer is between 10µm and 5µm, and does not generate static electricity during peeling. The thickness of the acoustic damping adhesive layer 30 is between 10µm and 50µm. The acoustic damping adhesive layer 30 is a rubber-based damping adhesive layer with a low glass transition temperature and a high damping factor. The thickness of the heavy release film 40 is between 40µm and 60µm. The heavy release film 40 is a heavy release silicone oil release film with self-antistatic effect, and does not generate static electricity during peeling. The release force of the heavy release film 40 is 15 gf / inch to 20 gf / inch.

[0038] The first and second acoustic films are taken from the same batch of acoustic film samples. When conducting bubble detection, 5 to 10 samples of the first and second acoustic films can be selected as a group for the experiment, but it is necessary to ensure that the number of the first and second acoustic films being tested is equal.

[0039] Step S2: Immerse the first acoustic membrane in a solution for a first duration, wherein the solution is at a first temperature.

[0040] In some embodiments, the first temperature is 20°C to 30°C, and the first duration is 20 min to 40 min.

[0041] The first acoustic diaphragm is immersed in a solution, which can be ordinary water such as mineral water or tap water. Deionized water, ultrapure water, or other highly purified water cannot be used. The purpose of immersing in water is to amplify the environment in which the acoustic diaphragm is located, especially since high humidity in the environment has a significant impact on the stability of the acoustic diaphragm.

[0042] For example, the first acoustic membrane is taken out using a standard A4 sampler and placed in a beaker containing tap water. The tap water needs to submerge the first acoustic membrane. The water temperature is 25°C, and the immersion time of the first acoustic membrane is 30 minutes.

[0043] Step S3: Place the second acoustic film at the first temperature for the first duration.

[0044] It should be noted that the ambient temperature and placement time of the second acoustic diaphragm are the same as those of the first acoustic diaphragm. The difference between the two is that the first acoustic diaphragm needs to be placed in water, while the second acoustic diaphragm does not require a water environment. The second acoustic diaphragm simulates the environment in which a normal acoustic diaphragm is placed.

[0045] For example, the second acoustic film is taken out using a standard A4 sampler, placed in a beaker, and then placed in an environment at 25°C for 30 minutes.

[0046] Please see Figure 3 , Figure 3 This is a schematic diagram illustrating a scenario where an acoustic film is placed in a container, as provided in an embodiment of this application. Figure 3 As shown, containers 50 and 60 can be beakers, test tubes, etc. Container 50 is filled with tap water, which submerges the first acoustic membrane 51. Container 60 contains only the second acoustic membrane 61. The openings of containers 50 and 60 do not require lids.

[0047] Step S4: Bake the first acoustic film and the second acoustic film at a second temperature for a second duration.

[0048] In some embodiments, the second temperature is 170°C to 180°C, and the second duration is 5 min to 10 min.

[0049] In some embodiments, the step of baking the first acoustic film and the second acoustic film at a second temperature for a second duration includes:

[0050] At a second temperature, pressure blocks are placed on the first acoustic film and the second acoustic film respectively, and the first acoustic film and the second acoustic film are baked for a second time.

[0051] In some embodiments, the mass of the compressed block is 1500g to 2500g.

[0052] When the first and second acoustic films begin baking, pressure blocks are placed on the first and second acoustic films respectively. The pressure blocks can increase the pressure on the films to reduce the baking time.

[0053] It should be noted that under high temperature and certain pressure, unreacted chemical groups will undergo side reactions and produce gas after absorbing water. For example, isocyanate adhesives are prone to absorbing water. Small molecules or solvents remaining in adhesive film samples that have not been soaked in water will evaporate and also produce gas. Gas bubbles will be generated at the interface between the damping adhesive layer and the release layer.

[0054] Step S5: Cool the first acoustic film and the second acoustic film to the third temperature respectively.

[0055] In some embodiments, the third temperature is 20°C to 25°C.

[0056] Step S6: Determine whether there are air bubbles in the first acoustic film and the second acoustic film.

[0057] In some embodiments, the bubbles are observed using a microscope.

[0058] Step S7: If air bubbles are present in the first acoustic film and / or the second acoustic film, then the first acoustic film and the second acoustic film are aged for a third time.

[0059] It should be noted that unreacted chemical groups in the first acoustic film will undergo side reactions and produce gas after absorbing water. Residual small molecules or solvents in the second acoustic film sample will also volatilize and produce gas. Therefore, when performing bubble detection, the presence of bubbles in either the first or second acoustic film indicates that the acoustic film sample has not been fully cured and needs to be further cured.

[0060] In some embodiments, the third duration is 3h to 5h.

[0061] If bubbles are present in either the first or second acoustic diaphragm, it indicates that there is solvent residue in the adhesive layer of the acoustic diaphragm, or that there are incompletely cured chemical groups. This means that the adhesive layer of the first and second acoustic diaphragms in the same batch has not been completely cured. If these incompletely cured diaphragms are directly laminated with LCP films, TPC films, TPU films, TPEE films, PEEK films, rubber films, etc., to make composite diaphragms, the bubbles will have difficulty permeating from the surface of these films during the curing process. As a result, bubbles will be generated during the hot pressing process of the diaphragm, and these bubbles are difficult to eliminate, ultimately leading to a large number of defective products.

[0062] Step S8: Repeat steps S1 to S7 for the first and second acoustic films that have been cured for a third time until there are no air bubbles in the first and second acoustic films.

[0063] In some embodiments, the method further includes counting the number of third duration cycles and calculating the total curing time of the first acoustic film and the second acoustic film.

[0064] Since the first and second acoustic films are part of the same batch of acoustic film samples, the total curing time obtained is representative. The batch of samples can be cured according to the obtained total curing time in the future.

[0065] This application provides a method for detecting air bubbles in an acoustic diaphragm. The method includes steps S1: providing a first acoustic diaphragm and a second acoustic diaphragm; step S2: immersing the first acoustic diaphragm in a solution at a first temperature for a first duration; step S3: placing the second acoustic diaphragm at the first temperature for the first duration; step S4: baking the first and second acoustic diaphragms at a second temperature for a second duration; step S5: cooling the first and second acoustic diaphragms to a third temperature; step S6: determining whether air bubbles exist in the first and second acoustic diaphragms; step S7: if air bubbles exist in the first and / or second acoustic diaphragms, aging the first and second acoustic diaphragms for a third duration; and step S8: repeating steps S1 to S7 until no air bubbles are present in the first and second acoustic diaphragms. This method can quickly and repeatedly test samples, and before mass production of adhesive films, it can detect bubbles in the adhesive film and determine whether there is solvent residue or whether the curing is complete. It can also calculate the curing time required for the samples, ensuring the quality of the materials before use, avoiding the generation of large quantities of defective products in the downstream processes, and greatly improving production efficiency.

[0066] The method for detecting air bubbles in acoustic films is described below with reference to specific embodiments:

[0067] Example 1

[0068] Step S1: Use a standard A4 sampler to obtain the first acoustic film and the second acoustic film respectively;

[0069] Step S2: Place the first acoustic membrane in a beaker containing tap water and soak for 30 minutes. The temperature of the tap water is 25°C.

[0070] Step S3: Place the second acoustic diaphragm in a beaker and place the beaker at 25°C for 30 minutes;

[0071] Step S4: Place 2kg pressure blocks on the first and second acoustic films respectively, mark them, and bake at 180℃ for 5 minutes.

[0072] Step S5: Cool the first acoustic diaphragm and the second acoustic diaphragm to 25°C respectively;

[0073] Step S6: Use an optical microscope to determine whether there are air bubbles in the first and second acoustic films;

[0074] Step S7: If air bubbles are present in the first acoustic diaphragm and / or the second acoustic diaphragm, then cure the first acoustic diaphragm and the second acoustic diaphragm for 4 hours.

[0075] Step S8: Repeat steps S1 to S7 for the first and second acoustic films that have been cured for 4 hours until there are no air bubbles in the first and second acoustic films.

[0076] Comparative Example 1

[0077] Step S1: Use a standard A4 sampler to obtain the first acoustic film and the second acoustic film respectively;

[0078] Step S2: Place the first acoustic membrane in a beaker containing tap water and soak for 30 minutes. The temperature of the tap water is 25°C.

[0079] Step S3: Place the second acoustic diaphragm in a beaker and place the beaker at 25°C for 30 minutes;

[0080] Step S4: Place 2kg pressing blocks on the first and second acoustic films respectively, mark them, and bake at 120℃ for 5 minutes;

[0081] Step S5: Cool the first acoustic diaphragm and the second acoustic diaphragm to 25°C respectively;

[0082] Step S6: Use an optical microscope to determine whether there are air bubbles in the first and second acoustic films;

[0083] Step S7: If air bubbles are present in the first acoustic diaphragm and / or the second acoustic diaphragm, then cure the first acoustic diaphragm and the second acoustic diaphragm for 4 hours.

[0084] Step S8: Repeat steps S1 to S7 for the first and second acoustic films that have been cured for 4 hours until there are no air bubbles in the first and second acoustic films.

[0085] Comparative Example 2

[0086] Step S1: Use a standard A4 sampler to obtain the first acoustic film and the second acoustic film respectively;

[0087] Step S2: Place the first acoustic membrane in a beaker containing tap water and soak for 30 minutes. The temperature of the tap water is 25°C.

[0088] Step S3: Place the second acoustic diaphragm in a beaker and place the beaker at 25°C for 30 minutes;

[0089] Step S4: Mark the first and second acoustic films and bake them at 60°C for 5 minutes.

[0090] Step S5: Cool the first acoustic diaphragm and the second acoustic diaphragm to 25°C respectively;

[0091] Step S6: Use an optical microscope to determine whether there are air bubbles in the first and second acoustic films;

[0092] Step S7: If air bubbles are present in the first acoustic diaphragm and / or the second acoustic diaphragm, then cure the first acoustic diaphragm and the second acoustic diaphragm for 4 hours.

[0093] Step S8: Repeat steps S1 to S7 for the first and second acoustic films that have been cured for 4 hours until there are no air bubbles in the first and second acoustic films.

[0094] It should be noted that the acoustic films used in Example 1, Comparative Example 1 and Comparative Example 2 are acoustic films from the same batch of samples.

[0095] Figure 4 This is a schematic diagram of the air bubbles in the acoustic film of Embodiment 1 of this application. Please refer to [link / reference]. Figure 4 ,in Figure 4 (a) indicates the air bubbles detected by the first acoustic membrane. Figure 4 (b) indicates the bubbles detected in the second acoustic film. Observation under an optical microscope at the same magnification shows that the bubble density of the first acoustic film is greater than that of the second acoustic film, indicating that there are unreacted chemical groups and uncured solvents in both the first and second acoustic films.

[0096] Figure 5 This is a schematic diagram of the air bubble in the acoustic film of Comparative Example 1 of this application. Please refer to [link / reference]. Figure 5 ,in Figure 5 (a) indicates the air bubbles detected by the first acoustic membrane. Figure 5 (b) shows the air bubbles detected by the second acoustic membrane, observed under an optical microscope at the same magnification as in Example 1, combined with... Figure 4 As can be seen from the acoustic films in 5(a) and 5(b), the first acoustic film in 5(a) and the second acoustic film in 5(b) have smaller bubble volumes and lower bubble densities compared to the first acoustic film in 4(a) and the second acoustic film in 4(b), indicating that the baking temperature of 120℃ cannot fully reveal the bubbles in the acoustic film.

[0097] Figure 6 This is a schematic diagram of the air bubbles in the acoustic film of Comparative Example 2 of this application. Please refer to [link / reference]. Figure 6 ,in Figure 6 (a) indicates the air bubbles detected by the first acoustic membrane. Figure 6 (b) shows the air bubbles detected by the second acoustic membrane, observed under an optical microscope at the same magnification as in Example 1, combined with... Figure 4As can be seen from the acoustic films in 6(a) and 6(b), the first acoustic film has almost no visible bubbles, indicating that there is no pressure block and the low baking temperature of 60°C cannot make the bubbles in the acoustic film visible.

[0098] In summary, the high temperature and certain pressure environment can cause unreacted chemical groups in the acoustic film to undergo side reactions and produce gas after absorbing water. This allows those skilled in the art to observe the process, ensuring the quality of the acoustic film material before use and avoiding the generation of large quantities of defective products in subsequent processes.

[0099] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of this application, and not to limit them; under the concept of this application, the technical features of the above embodiments or different embodiments can also be combined, the steps can be implemented in any order, and there are many other variations of different aspects of this application as described above, which are not provided in detail for the sake of brevity; although this application has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the foregoing embodiments, or make equivalent substitutions for some of the technical features; and these modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of this application.

Claims

1. A method of detecting bubbles in an acoustic adhesive film, characterized by, The method comprises: Step S1: providing a first acoustic adhesive film and a second acoustic adhesive film; Step S2: soaking the first acoustic adhesive film in a solution for a first time duration, the solution being at a first temperature; Step S3: placing the second acoustic adhesive film at the first temperature for the first time duration; Step S4: placing a pressing block on the first acoustic adhesive film and the second acoustic adhesive film respectively at a second temperature, and baking the first acoustic adhesive film and the second acoustic adhesive film for a second time duration; the mass of the pressing block is 1500g-2500g; the second temperature is 170℃-180℃, and the second time duration is 5min-10min; Step S5: cooling the first acoustic adhesive film and the second acoustic adhesive film to a third temperature respectively; Step S6: determining whether the first acoustic adhesive film and the second acoustic adhesive film have bubbles; Step S7: if the first acoustic adhesive film and / or the second acoustic adhesive film has bubbles, then aging the first acoustic adhesive film and the second acoustic adhesive film for a third time duration; Step S8: recycling the first acoustic adhesive film and the second acoustic adhesive film aged for the third time duration through steps S1-S7 until the first acoustic adhesive film and the second acoustic adhesive film have no bubbles.

2. The bubble detection method according to claim 1, characterized by, The method further comprises counting the number of times of recycling the third time duration, and calculating the total time duration of aging the first acoustic adhesive film and the second acoustic adhesive film.

3. The bubble detection method of claim 1, wherein The first temperature is 20℃-30℃, and the first time duration is 20min-40min.

4. The bubble detection method of claim 1, wherein The first acoustic adhesive film and the second acoustic adhesive film each comprise a light release layer, an acoustic damping adhesive layer, and a heavy release film; the acoustic damping adhesive layer is stacked between the light release layer and the heavy release film.

5. The bubble detection method of claim 2, wherein, The bubbles are observed through a microscope.

6. The bubble detection method of claim 2, wherein The third time duration is 3h-5h.

7. The bubble detection method of claim 1, wherein The third temperature is 20℃-25℃.

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