Method for testing curing shrinkage rate of thermosetting laminated adhesive film

Abstract

The invention relates to the technical field of lamination adhesive film detection, in particular to a method for testing the curing shrinkage rate of a thermosetting lamination adhesive film. The method for testing the curing shrinkage rate of the thermosetting laminated adhesive film comprises the following steps: (a) removing a support film and a protective film of a group of samples to be tested, testing the density of the thermosetting laminated adhesive film in the samples to be tested before curing, and recording the density as rho1; (b) removing the protective film of the other group of samples to be detected, placing the samples on the surface of the base material to enable the thermosetting lamination adhesive film to be attached to the base material, and performing vacuum laminating treatment; then removing the supporting film, and then carrying out curing treatment; directly stripping the cured thermosetting laminated adhesive film from the surface of the base material, testing the density, and recording the density as rho2; the curing shrinkage rate X of the thermosetting laminated adhesive film to be detected is equal to (1-rho1 / rho2) * 100%; wherein the release force of the base material is 1-50 gf / 25 mm. The test method provided by the invention can accurately measure the volume shrinkage of the thermosetting laminated adhesive film.

Description

Technical Field

[0001] This invention relates to the field of laminated film testing technology, and in particular to a method for testing the curing shrinkage rate of thermosetting laminated films. Background Technology

[0002] In semiconductor packaging, build-up film is a core material used in multilayer interconnect structures, primarily serving functions such as insulation, bonding, stress buffering, and signal transmission protection. Its performance directly affects the reliability and yield of the package. During the thermosetting curing process, the build-up film undergoes volume shrinkage. This thermosetting curing shrinkage not only leads to interlayer misalignment and warping, affecting the alignment accuracy of the multilayer structure, but also the internal stress generated by curing shrinkage can cause microcracks and delamination, impacting the product's packaging reliability. Therefore, accurately measuring the curing shrinkage rate of the build-up film is crucial for optimizing product design.

[0003] In view of this, the present invention is hereby proposed. Summary of the Invention

[0004] The purpose of this invention is to provide a test method for the curing shrinkage rate of thermosetting laminated films, so as to solve the technical problem of lacking an effective means to directly measure the intrinsic curing shrinkage rate of thermosetting laminated films in the prior art.

[0005] To achieve the above-mentioned objectives of this invention, this invention provides a method for testing the curing shrinkage rate of thermosetting laminated adhesive films, comprising the following steps: (a) Take a membrane structure containing the thermosetting laminated film to be tested and cut it to obtain two sets of parallel test samples; the membrane structure includes a thermosetting laminated film, a support film attached to one side of the thermosetting laminated film, and an optional protective film attached to the other side of the thermosetting laminated film; remove the support film and optional protective film of one set of test samples, test the density of the thermosetting laminated film in the test sample before curing, and record it as ρ1; (b) Remove the optional protective film from another set of the test samples, place them on the substrate surface to adhere the thermosetting laminated film to the substrate, and perform vacuum pressing; then remove the support film and perform curing; peel the cured thermosetting laminated film directly from the surface of the substrate, and test the density of the cured thermosetting laminated film, recording it as ρ2; the curing shrinkage rate of the test thermosetting laminated film X = (1 - ρ1 / ρ2) × 100%; In step (b), the release force of the substrate is 1 to 50 gf / 25 mm.

[0006] In a specific embodiment of the present invention, the release force of the substrate is 2 to 25 gf / 25 mm.

[0007] In a specific embodiment of the present invention, the substrate includes at least one of aluminum foil, copper foil, and PTFE.

[0008] In a specific embodiment of the present invention, the thickness of the substrate is 10 to 100 μm.

[0009] In a specific embodiment of the present invention, the size of the substrate is greater than or equal to the size of the thermosetting laminated film that is bonded to it, such that the outer edge of the substrate overlaps with the outer edge of the thermosetting laminated film or extends outward relative to the outer edge of the thermosetting laminated film.

[0010] In a specific embodiment of the present invention, during the vacuum pressing process, the temperature of the vacuum section is 90–140°C, and the vacuum degree is less than or equal to 1 Torr; the pressure of the pressing section is 3–11 kgf / cm². 2 Further, the vacuum pressing process includes: treatment at 90–140°C and ≤1 Torr for 25–35 seconds, followed by pressing at 3–11 kgf / cm² at 90–140°C and ≤1 Torr. 2 Press for 25–35 seconds.

[0011] In a specific embodiment of the present invention, the curing conditions are the same as those for the curing treatment of the thermosetting laminated film to be tested in actual applications.

[0012] In a specific embodiment of the present invention, each group of parallel test samples includes at least three parallel test samples.

[0013] In a specific embodiment of the present invention, the size of the sample to be tested is (15-40) cm × (15-40) cm.

[0014] In a specific embodiment of the present invention, in steps (a) and (b), the density is tested using the water displacement method.

[0015] Compared with the prior art, the beneficial effects of the present invention are as follows: The testing method of this invention uses a substrate with release effect to bond with the thermosetting laminated film to be tested, followed by vacuum pressing and subsequent curing. On the one hand, the substrate with release effect does not affect the free shrinkage of the thermosetting laminated film during the curing process. On the other hand, the substrate with release effect can ensure that the cured thermosetting laminated film can be directly and completely peeled off from the surface of the substrate, thereby enabling accurate measurement of the volume shrinkage rate of the thermosetting laminated film.

[0016] This invention innovatively establishes a measurement system for the volume change of thermosetting multilayer films during the thermosetting process, enabling accurate quantification of their curing shrinkage characteristics. This overcomes the bottleneck of existing technologies that cannot accurately measure the intrinsic shrinkage rate of thermosetting multilayer films, providing crucial data support for optimizing packaging process parameters, improving interlayer alignment accuracy, and enhancing device reliability. The implementation of this invention not only fills a technological gap in this field but also provides an important testing methodology foundation for the development of advanced semiconductor packaging technologies. Attached Figure Description

[0017] To more clearly illustrate the specific embodiments of the present invention or the technical solutions in the prior art, the drawings used in the description of the specific embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of the present invention. For those skilled in the art, other drawings can be obtained from these drawings without creative effort.

[0018] Figure 1 This is a photograph of the thermosetting laminated adhesive film and the substrate provided in Embodiment 1 of the present invention after vacuum bonding; Figure 2 A photograph of the thermosetting laminated adhesive film provided in Comparative Example 5 after it has been bonded to the substrate. Detailed Implementation

[0019] The technical solution of the present invention will be clearly and completely described below with reference to the accompanying drawings and specific embodiments. However, those skilled in the art will understand that the embodiments described below are some embodiments of the present invention, but not all embodiments, and are only used to illustrate the present invention, and should not be regarded as limiting the scope of the present invention. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention. Where specific conditions are not specified in the embodiments, conventional conditions or conditions recommended by the manufacturer shall be followed. Where the manufacturers of reagents or instruments are not specified, they are all conventional products that can be purchased commercially.

[0020] Chinese patent application CN113189135A discloses a method for determining the heat shrinkage rate of an encapsulating film. It simulates a real-world application scenario by measuring the changes in transverse (TD) and longitudinal (MD) directions before and after heat treatment. This method is suitable for determining the heat shrinkage rate of photovoltaic module encapsulating films, such as ethylene-vinyl acetate polymer films, polyvinyl butyral films, and polyolefin encapsulating films. However, this method is not suitable for thermosetting films because thermosetting films melt during heating and curing, and talc powder enters the molten film. Furthermore, after curing, the film adheres to the aluminum alloy substrate, affecting the accuracy of the test results. Chinese patent application CN113777287A discloses a method for testing the curing shrinkage rate of an adhesive. This method requires the adhesive to be fluid and is not suitable for testing the curing shrinkage rate of pre-formed films of a certain thickness.

[0021] Currently, there is no suitable testing method for measuring the curing shrinkage rate of thermosetting laminated adhesive films. The inventors of this invention discovered that when the linear shrinkage rate testing method used for general plastic films is applied to laminated films to test their thermal shrinkage rate in the TD / MD direction, the melted laminated film adheres to the substrate during the curing process, and the substrate's thermal deformation properties affect the determination of the film's linear shrinkage rate. If the volume shrinkage rate testing method used for adhesives is applied to laminated films, the film needs to be placed in a specific mold (such as a specific gravity bottle), and air bubbles must not be generated during curing; otherwise, the density measurement after curing will be inaccurate. Furthermore, removing the cured film from the mold in actual testing is also challenging. Because laminated films are already formed, they are generally thin, making stacking them in a specific mold difficult, and air bubbles are inevitably generated during curing. Therefore, due to the lack of effective testing methods, the curing shrinkage rate of laminated films is difficult to measure accurately. This technical bottleneck severely restricts the optimization of film material performance and the improvement of encapsulation processes.

[0022] Based on this, the present invention provides a method for testing the curing shrinkage rate of thermosetting laminated adhesive films, comprising the following steps: (a) Take a membrane structure containing the thermosetting laminated film to be tested and cut it to obtain two sets of parallel test samples; the membrane structure includes a thermosetting laminated film, a support film attached to one side of the thermosetting laminated film, and an optional protective film attached to the other side of the thermosetting laminated film; remove the support film and optional protective film of one set of test samples, test the density of the thermosetting laminated film in the test sample before curing, and record it as ρ1; (b) Remove the optional protective film from another set of test samples, place them on the substrate surface to adhere the thermosetting laminated film to the substrate, and perform vacuum pressing; then remove the support film and perform curing; peel the cured thermosetting laminated film directly from the surface of the substrate and test the density of the cured thermosetting laminated film, recording it as ρ2; the curing shrinkage rate of the test thermosetting laminated film X = (1 - ρ1 / ρ2) × 100%; In step (b), the release force of the substrate is 1 to 50 gf / 25 mm.

[0023] The testing method of this invention uses a substrate with release effect to bond with the thermosetting laminated film to be tested, followed by vacuum pressing and subsequent curing. On the one hand, the substrate with release effect does not affect the free shrinkage of the thermosetting laminated film during the curing process. On the other hand, the substrate with release effect can ensure that the cured thermosetting laminated film can be directly and completely peeled off from the surface of the substrate, thereby enabling accurate measurement of the volume shrinkage rate of the thermosetting laminated film.

[0024] Furthermore, after the substrate and the thermosetting laminated film to be tested are bonded together, a vacuum pressing method is used to ensure that the thermosetting laminated film and the substrate are tightly bonded without gaps, thus avoiding the impact of air bubbles generated during subsequent curing on the accuracy of the test results.

[0025] In the membrane structure of this invention, the support film and protective film located on the two surfaces of the thermosetting laminated film are not limited. For example, the support film includes, but is not limited to, polyethylene terephthalate (PET) film, and the protective film includes, but is not limited to, biaxially oriented polypropylene (BOPP) film. Furthermore, the optional protective film means that the membrane structure may or may not include a protective film. In actual testing, the protective film will be removed, so whether or not the membrane structure includes a protective film does not affect the test of the curing shrinkage rate of the thermosetting laminated film. In addition, the thickness of the thermosetting laminated film in the membrane structure of this invention is not limited and can be the same as the thickness of the laminated film used in actual applications to more accurately reflect the curing shrinkage rate of the laminated film in real application scenarios.

[0026] The release force of the substrate used in this invention can be within the range of 1gf / 25mm, 2gf / 25mm, 5gf / 25mm, 10gf / 25mm, 15gf / 25mm, 20gf / 25mm, 25gf / 25mm, 30gf / 25mm, 35gf / 25mm, 40gf / 25mm, 45gf / 25mm, 50gf / 25mm, or any combination thereof. This helps to balance vacuum pressing and peeling after curing. If the release force is too small, relative slippage may occur during vacuum pressing; if the release force is too large, the substrate will affect the free shrinkage of the thermosetting laminate film during curing, and peeling will be difficult after curing. The preferred release force of the substrate used in this invention is 2 to 25gf / 25mm, such as 10 to 25gf / 25mm.

[0027] In a specific embodiment of the present invention, the substrate includes at least one of aluminum foil, copper foil, and PTFE. The substrate of the present invention has small thermal deformation, and further combined with its own release force, the substrate does not affect the free shrinkage of the thermosetting laminated film during the curing process of the vacuum-pressed structure, thus accurately reflecting the curing shrinkage of the laminated film.

[0028] In a specific embodiment of the present invention, the thickness of the substrate is 10 to 100 μm.

[0029] In a specific embodiment of the present invention, the size of the substrate is greater than or equal to the size of the thermosetting laminated film to which it is bonded, such that the outer edge of the substrate overlaps with the outer edge of the thermosetting laminated film or extends outward relative to the outer edge of the thermosetting laminated film. For example, the outer edge of the substrate may extend outward by more than 2 cm relative to the outer edge of the thermosetting laminated film, but is not limited thereto.

[0030] In a specific embodiment of the present invention, during the vacuum pressing process, the temperature of the vacuum section is 90–140°C, for example, 100–120°C, and the vacuum degree is less than or equal to 1 Torr; the pressure of the pressing section is 3–11 kgf / cm². 2 .

[0031] In different embodiments, during vacuum pressing, the temperature for vacuum can be a range of 90°C, 100°C, 105°C, 110°C, 115°C, 120°C, 130°C, 140°C, or any combination thereof; the vacuum level can be a range of 1 Torr, 0.9 Torr, 0.8 Torr, 0.7 Torr, 0.6 Torr, 0.5 Torr, or any combination thereof; and the pressure in the pressing section can be 3 kgf / cm². 2 4kgf / cm 2 5kgf / cm 2 6kgf / cm 27kgf / cm 2 8kgf / cm 2 9kgf / cm 2 10 kgf / cm 2 11 kgf / cm 2 Or a range consisting of any two of them.

[0032] In a specific embodiment of the present invention, the vacuum pressing process includes: processing at 90–140°C and ≤1 Torr for 25–35 seconds, followed by processing at 90–140°C and ≤1 Torr with a pressure of 3–11 kgf / cm². 2 Pressing for 25–35 seconds. Further, the vacuum pressing process includes: processing at 100°C and ≤1 Torr for 30 seconds, then maintaining the temperature and vacuum level of the vacuum pressing process at 7 kgf / cm². 2 Press for 30 seconds. The vacuum pressing process of this invention can be performed in a vacuum laminator.

[0033] In a specific embodiment of the present invention, the curing conditions are the same as those used in the actual application of the thermosetting laminated film under test. Using curing conditions consistent with actual applications directly reflects the curing shrinkage behavior of the thermosetting laminated film in the actual production environment, thus providing a basis for optimizing product design.

[0034] In a specific embodiment of the present invention, each group of parallel test samples includes at least three parallel test samples.

[0035] In a specific embodiment of the present invention, the size of the sample to be tested is (15-40) cm × (15-40) cm.

[0036] In a specific embodiment of the present invention, the density is tested using the drainage method in steps (a) and (b). The thermosetting laminated adhesive film to be tested in the present invention can shrink freely during the curing process and can be directly and completely peeled off from the substrate surface after curing. By testing with the drainage method, the shrinkage in various directions can be monitored, reflecting the true volume shrinkage rate.

[0037] The laminated films used in the following specific embodiments of the present invention are all commercially available conventional laminated films, including thermosetting laminated films and support films and protective films respectively attached to both sides of the thermosetting laminated film. The support film is made of PET material and the protective film is made of BOPP material. The purpose of introducing specific laminated films in the present invention is only to illustrate the test method of the present invention, and should not be construed as a limitation on the types of laminated films.

[0038] Laminated film 1, commercially available; Laminated film 2, commercially available; Laminated film 3, commercially available; Laminated film 4, commercially available.

[0039] Example 1 This embodiment provides a method for testing the curing shrinkage rate of thermosetting laminated adhesive films, including the following steps: (1) Cut six parallel samples of the same size (20cm×20cm) from laminated film 1 using a mold; take three of the samples, remove the support film and protective film, and test the density of the uncured thermosetting laminated film using the water displacement method, and record it as ρ. 11 ρ 12 ρ 13 Calculate the average value ρ1 = (ρ 11 +ρ 12 +ρ 13 ) / 3.

[0040] (2) Using a mold, cut three parallel substrates of the same size (20cm×20cm) from an aluminum foil (manufacturer: Huizhou Best Film Industry Co., Ltd., model: UTRF-23 aluminum foil) with a release force of 15gf / 25mm and a thickness of 23μm. Take the other three samples from step (1), remove the protective film, and then place the three samples on the three substrates respectively, with the thermosetting laminated film side of the sample facing the substrate (containing the release agent side), and then place them in a vacuum laminator for vacuum pressing. The vacuum pressing conditions are: treatment at 100℃ and ≤1Torr for 30s, and then at 100℃ and ≤1Torr for 7kgf / cm 2 Press for 30 seconds.

[0041] (3) Remove the support film from the three samples after vacuum pressing in step (2), and then place them in an oven for curing. The curing temperature is the same as the actual curing temperature of the laminated film 1, specifically: keep at 130℃ for 30 min, then keep at 170℃ for 30 min, and then keep at 190℃ for 60 min. Peel the three cured thermosetting laminated films directly from the surface of the substrate, and test the density of the cured thermosetting laminated films using the water displacement method, and record it as ρ. 21 ρ 22 ρ 23 Calculate the average value ρ2 = (ρ 21 +ρ 22 +ρ 23 ) / 3.

[0042] The curing shrinkage rate of the thermosetting laminated film in laminated film 1 is calculated based on the curing shrinkage rate X = (1-ρ1 / ρ2)×100%.

[0043] Example 2 This embodiment refers to the test method for the curing shrinkage rate of thermosetting laminated film in Embodiment 1, the only difference being that the laminated film being tested is different.

[0044] The laminated film tested in this embodiment is a commercially available laminated film 2.

[0045] Example 3 This embodiment refers to the test method for the curing shrinkage rate of thermosetting laminated film in Embodiment 1, the only difference being that the laminated film being tested is different.

[0046] The laminated film tested in this embodiment is a commercially available laminated film 3.

[0047] Example 4 This embodiment refers to the test method for the curing shrinkage rate of thermosetting laminated film in Embodiment 1, the only difference being that the test object is a different laminated film.

[0048] The laminated film tested in this embodiment is a commercially available laminated film 4.

[0049] Comparative Example 1 The test method for the curing shrinkage rate of comparative thermosetting laminated adhesive films includes the following steps: (1) Cut six parallel samples of the same size (20cm×20cm) from laminated film 1 using a mold; take three of the samples, remove the support film and protective film, and test the density of the uncured thermosetting laminated film using the water displacement method, and record it as ρ. 11 ρ 12 ρ 13 Calculate the average value ρ1 = (ρ 11 +ρ 12 +ρ 13 ) / 3.

[0050] (2) Take the other 3 samples from step (1), remove the protective film, and then place the 3 samples on a glass plate with the support film side of the sample facing the glass plate. Use high-temperature tape to stick the sample to the glass plate around its perimeter. Then place it in an oven to cure. The curing temperature is the same as the actual curing temperature of the laminated film 1, specifically: keep it at 130℃ for 30 min, then at 170℃ for 30 min, and then at 190℃ for 60 min. Peel the 3 cured thermosetting laminated films from the surface of the support film, and test the density of the cured thermosetting laminated films using the water displacement method. Record the density as ρ. 21 ρ 22 ρ 23 Calculate the average value ρ2 = (ρ 21 +ρ 22 +ρ 23 ) / 3.

[0051] The curing shrinkage rate of the thermosetting laminated film in laminated film 1 is calculated based on the curing shrinkage rate X = (1-ρ1 / ρ2)×100%.

[0052] Comparative Example 2 The test method for the curing shrinkage rate of comparative thermosetting laminated adhesive films includes the following steps: (1) Cut six parallel samples of the same size (20cm×20cm) from the laminated film 2 using a mold; take three of the samples, remove the support film and protective film, and test the density of the uncured thermosetting laminated film using the water displacement method, and record it as ρ. 11 ρ 12 ρ 13 Calculate the average value ρ1 = (ρ 11 +ρ 12 +ρ 13 ) / 3.

[0053] (2) Take the other 3 samples from step (1), remove the protective film, and then place the 3 samples on a glass plate with the support film side of the sample facing the glass plate. Use high-temperature tape to stick the sample to the glass plate around its perimeter. Then place it in an oven to cure. The curing temperature is the same as the actual curing temperature of the laminated film 2, specifically: keep it at 130℃ for 30 min, then at 170℃ for 30 min, and then at 190℃ for 60 min. Peel the 3 cured thermosetting laminated films from the surface of the support film and test the density of the cured thermosetting laminated films using the water displacement method. Record the density as ρ. 21 ρ 22 ρ 23 Calculate the average value ρ2 = (ρ 21 +ρ 22 +ρ 23 ) / 3.

[0054] The curing shrinkage rate of the thermosetting laminated film in laminated film 2 is calculated based on the curing shrinkage rate X = (1-ρ1 / ρ2)×100%.

[0055] Comparative Example 3 The test method for the curing shrinkage rate of comparative thermosetting laminated adhesive films includes the following steps: (1) Cut six parallel samples of the same size (20cm×20cm) from laminated film 1 using a mold; take three of the samples, remove the support film and protective film, and test the density of the uncured thermosetting laminated film using the water displacement method, and record it as ρ. 11 ρ 12 ρ 13 Calculate the average value ρ1 = (ρ 11 +ρ 12 +ρ 13 ) / 3.

[0056] (2) Take the other 3 samples from step (1), remove the protective film, and then place the 3 samples on a glass plate with the support film side of the sample facing the glass plate. Then place them in an oven to cure. The curing temperature is the same as the actual curing temperature of the laminated film 1, specifically: keep at 130℃ for 30 min, then keep at 170℃ for 30 min, and then keep at 190℃ for 60 min. Peel the 3 cured thermosetting laminated films from the surface of the support film, and test the density of the cured thermosetting laminated films using the water displacement method. Record the density as ρ. 21 ρ 22 ρ 23 Calculate the average value ρ2 = (ρ 21 +ρ 22 +ρ 23 ) / 3.

[0057] The curing shrinkage rate of the thermosetting laminated film in laminated film 1 is calculated based on the curing shrinkage rate X = (1-ρ1 / ρ2)×100%.

[0058] Comparative Example 4 The test method for the curing shrinkage rate of comparative thermosetting laminated adhesive films includes the following steps: (1) Cut six parallel samples of the same size (20cm×20cm) from the laminated film 2 using a mold; take three of the samples, remove the support film and protective film, and test the density of the uncured thermosetting laminated film using the water displacement method, and record it as ρ. 11 ρ 12 ρ 13 Calculate the average value ρ1 = (ρ 11 +ρ 12 +ρ 13 ) / 3.

[0059] (2) Take the other 3 samples from step (1), remove the protective film, and then place the 3 samples on the glass plate with the protective film side facing the glass plate. Then place them in an oven to cure. The curing temperature is the same as the actual curing temperature of the laminated film 2, specifically: keep at 130℃ for 30 min, then keep at 170℃ for 30 min, and then keep at 190℃ for 60 min. Peel the 3 cured thermosetting laminated films from the surface of the support film, and test the density of the cured thermosetting laminated films using the water displacement method. Record the density as ρ. 21 ρ 22 ρ 23 Calculate the average value ρ2 = (ρ 21 +ρ 22 +ρ 23 ) / 3.

[0060] The curing shrinkage rate of the thermosetting laminated film in laminated film 2 is calculated based on the curing shrinkage rate X = (1-ρ1 / ρ2)×100%.

[0061] Comparative Example 5 The test method for the curing shrinkage rate of the thermosetting laminated adhesive film in Comparative Example 5 includes the following steps: (1) Cut six parallel samples of the same size (20cm×20cm) from laminated film 1 using a mold; take three of the samples, remove the support film and protective film, and test the density of the uncured thermosetting laminated film using the water displacement method, and record it as ρ. 11 ρ 12 ρ 13 Calculate the average value ρ1 = (ρ 11 +ρ 12 +ρ 13 ) / 3.

[0062] (2) Using a mold, cut three parallel substrates of the same size (20cm×20cm) from an aluminum foil (manufacturer: Huizhou Best Film Co., Ltd., model: UTRF-23 aluminum foil) with a release force of 15gf / 25mm and a thickness of 23μm. Take the other three samples from step (1), remove the protective film, and then place the three samples naturally on the three substrates, with the thermosetting laminated film side of the sample facing the substrate.

[0063] (3) Remove the support film from the three samples in step (2), and then place them in an oven for curing. The curing temperature is the same as the actual curing temperature of the laminated film 1, specifically: keep at 130℃ for 30 min, then keep at 170℃ for 30 min, and then keep at 190℃ for 60 min. Remove the three cured thermosetting laminated films from the surface of the substrate, and test the density of the cured thermosetting laminated films using the water displacement method, and record it as ρ. 21 ρ 22 ρ 23 Calculate the average value ρ2 = (ρ 21 +ρ 22 +ρ 23 ) / 3.

[0064] The curing shrinkage rate of the thermosetting laminated film in laminated film 1 is calculated based on the curing shrinkage rate X = (1-ρ1 / ρ2)×100%.

[0065] Comparative Example 6 The test method for the curing shrinkage rate of the thermosetting laminated adhesive film in Comparative Example 6 includes the following steps: (1) Cut six parallel samples of the same size (20cm×20cm) from laminated film 1 using a mold; take three of the samples, remove the support film and protective film, and test the density of the uncured thermosetting laminated film using the water displacement method, and record it as ρ. 11 ρ 12 ρ 13 Calculate the average value ρ1 = (ρ 11 +ρ 12 +ρ 13 ) / 3.

[0066] (2) Using a mold, cut three parallel substrates of the same size (20cm × 20cm) from a standard aluminum foil (23μm thick) without release agent. Take the other three samples from step (1), remove the protective film, and then place the three samples on the three substrates respectively, with the thermosetting laminate side of the sample facing the substrate, and then place them in a vacuum laminator for vacuum pressing. The vacuum pressing conditions are: treatment at 100℃ and ≤1 Torr for 30s, and then at 100℃ and ≤1 Torr for 7kgf / cm 2 Press for 30 seconds.

[0067] (3) Remove the support film from the three samples after vacuum pressing in step (2), and then place them in an oven for curing. The curing temperature is the same as the actual curing temperature of the laminated film 1, specifically: keep at 130℃ for 30 min, then keep at 170℃ for 30 min, and then keep at 190℃ for 60 min. The three cured thermosetting laminated films cannot be directly peeled off from the surface of the substrate, making it difficult to test the density of the cured thermosetting laminated films by the drainage method.

[0068] Experimental Example Figure 1 This is a photograph of the thermosetting laminated film and the substrate after vacuum bonding in Example 1. Figure 2 This is a photograph of the thermosetting laminated adhesive film of Comparative Example 5 after being bonded to the substrate. As can be seen from the image, in Comparative Example 5, the thermosetting laminated adhesive film was directly bonded to the substrate, resulting in gaps between the film and the substrate. This gaps can generate air bubbles during the subsequent curing process, affecting the test results. In contrast, in Example 1, the thermosetting laminated adhesive film and the substrate were vacuum-pressed together, eliminating the influence of air and allowing for a more accurate measurement of the curing shrinkage rate of the thermosetting laminated adhesive film.

[0069] The results of curing shrinkage rate tests using different embodiments and comparative examples of the present invention are shown in Table 1.

[0070] Table 1. Test results of different embodiments and comparative examples

[0071] As can be seen from the above test results, the test method of the present invention uses a substrate with release effect to bond with the thermosetting laminated film to be tested, and performs vacuum pressing and subsequent curing treatment. On the one hand, the substrate with release effect does not affect the free shrinkage of the thermosetting laminated film during the curing process. On the other hand, the substrate with release effect can ensure that the cured thermosetting laminated film can be directly and completely peeled off from the surface of the substrate, thereby enabling accurate measurement of the volume shrinkage rate of the thermosetting laminated film.

[0072] The test results of Examples 1-2 and Comparative Examples 1-2 show that when the support film of the laminated film itself is used as the substrate and the sample is pasted onto the glass plate with high-temperature tape to fix the sample, both the thermosetting laminated film and the support film will shrink during the curing process. However, because it is fixed to the glass plate by the high-temperature tape, stress accumulation occurs between the thermosetting laminated film layer and the support film, which affects the test results.

[0073] The test results of Examples 1-2 and Comparative Examples 3-4 show that when the support film of the laminated film itself is used as the substrate and the sample is placed directly on the glass plate without the use of high-temperature tape for fixation, the thermosetting laminated film layer and the support film will shrink together during the curing process, affecting the test results.

[0074] The test results of Example 1 and Comparative Example 5 show that when aluminum foil with low release force is used as the substrate, and thermosetting laminated film is directly and naturally placed on the substrate for curing, bubbles will be generated in the thermosetting laminated film during the curing process, making accurate measurement impossible.

[0075] The test results of Example 1 and Comparative Example 6 show that when conventional aluminum foil without release agent is used as the substrate, the laminated adhesive film is bonded to the substrate by vacuum pressing and cured. The cured laminated adhesive film cannot be peeled off from the substrate and cannot be used for subsequent tests.

[0076] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, and not to limit them; although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some or all 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 the present invention.

Claims

1. A method for testing the curing shrinkage rate of thermosetting laminated adhesive films, characterized in that, Includes the following steps: (a) Take a membrane structure containing the thermosetting laminated film to be tested and cut it to obtain two sets of parallel test samples; the membrane structure includes a thermosetting laminated film, a support film attached to one side of the thermosetting laminated film, and an optional protective film attached to the other side of the thermosetting laminated film; remove the support film and optional protective film of one set of test samples, test the density of the thermosetting laminated film in the test sample before curing, and record it as ρ1; (b) Remove the optional protective film from another set of the test samples, place them on the substrate surface to adhere the thermosetting laminated film to the substrate, and perform vacuum pressing; then remove the support film and perform curing; peel the cured thermosetting laminated film directly from the surface of the substrate, and test the density of the cured thermosetting laminated film, recording it as ρ2; the curing shrinkage rate of the test thermosetting laminated film X = (1 - ρ1 / ρ2) × 100%; In step (b), the release force of the substrate is 1 to 50 gf / 25 mm.

2. The test method according to claim 1, characterized in that, The release force of the substrate is 2 to 25 gf / 25 mm.

3. The test method according to claim 1, characterized in that, The substrate includes at least one of aluminum foil, copper foil, and PTFE.

4. The test method according to claim 1, characterized in that, The thickness of the substrate is 10–100 μm.

5. The test method according to claim 1, characterized in that, The size of the substrate is greater than or equal to the size of the thermosetting laminated film that is bonded to it, such that the outer edge of the substrate overlaps with the outer edge of the thermosetting laminated film or extends outward relative to the outer edge of the thermosetting laminated film.

6. The test method according to claim 1, characterized in that, In the vacuum pressing process, the temperature of the vacuum section is 90–140°C, and the vacuum degree is less than or equal to 1 Torr; the pressure of the pressing section is 3–11 kgf / cm². 2 ; Preferably, the vacuum pressing process includes: processing at 90–140°C and ≤1 Torr for 25–35 seconds, followed by pressing at 3–11 kgf / cm² at 90–140°C and ≤1 Torr. 2 Press for 25–35 seconds.

7. The test method according to claim 1, characterized in that, The curing conditions are the same as those for the curing of the thermosetting laminated film under test in actual applications.

8. The test method according to claim 1, characterized in that, Each group of parallel test samples must include at least three parallel test samples.

9. The test method according to claim 1, characterized in that, The size of the sample to be tested is (15~40)cm×(15~40)cm.

10. The test method according to claim 1, characterized in that, In steps (a) and (b), the density is tested using the water displacement method.

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