A method for preparing anisotropic conductive adhesive film with improved adhesive overflow

Abstract

The present invention relates to a method for preparing an anisotropic conductive adhesive film with improved adhesive overflow, belonging to the technical field of anisotropic conductive adhesive films. The present invention discloses a method for preparing anisotropic conductive adhesive film with improved adhesive overflow, comprising: coating a pretreated anisotropic conductive adhesive solution, performing a primary drying process, pre-cutting, performing a secondary drying process, cutting, and winding; the pre-cutting process comprises passing the partially dried anisotropic conductive adhesive film through a pre-cutting device comprising upper and lower rollers to remove a portion of the anisotropic conductive adhesive layer on the release film layer, thereby forming a pre-cut groove.

Description

Technical Field

[0001] The invention belongs to the technical field of anisotropic conductive adhesive films and relates to a preparation method of anisotropic conductive adhesive film with improved adhesive overflow. Background Art

[0002] Anisotropic conductive film requires cutting before it can be used in electronic devices, display panels, chips, and other applications. Conventional cutting methods involve using a cutting tool to cut the desired width. This process can cause the film to adhere to the cutting tool, requiring frequent cleaning and the use of large amounts of organic cleaning agents, which pollutes the environment and reduces production efficiency. Furthermore, existing cutting methods can easily cause the conductive adhesive to separate from the film due to the force of the cutting.

[0003] In response to the above problems, the Chinese patent publication (publication number CN215094028U) sets a single-sided upper roller annular cutting knife, and adopts a method in which the cutting knife first contacts the thin film layer of the anisotropic conductive film, and then rotates and cuts the formed conductive film. However, the above method is for cutting the finished anisotropic conductive film, and the width of the obtained anisotropic conductive film is the same as the width of the release film. During the reel winding process, due to the action of force, glue overflow will occur, and the overflowed glue will stick to the inner side of the reel disk and the side of the film body, thereby causing poor reverse peeling. In the subsequent application process, the anisotropic conductive film roll is unrolled, cut into the required length, and bonded to the display panel and other devices. Summary of the Invention

[0004] The purpose of the present invention is to address the above-mentioned problems existing in the prior art and to propose a method for preparing anisotropic conductive adhesive film that improves the adhesive overflow problem.

[0005] The purpose of the present invention can be achieved through the following technical solutions:

[0006] A method for preparing anisotropic conductive adhesive film with improved adhesive overflow, the method comprising: coating a pretreated anisotropic conductive adhesive solution, drying it for the first time, pre-cutting it, drying it for the second time, cutting it, and rolling it up;

[0007] Pre-cutting includes passing the incompletely dried anisotropic conductive adhesive film through a pre-cutting device including an upper roller and a lower roller to remove part of the anisotropic conductive colloid layer on the release film layer to form a pre-cut groove.

[0008] During the reel winding process, the ACF glue will overflow due to the action of force, and the overflowed glue will stick to the inner side of the reel plate and the side of the film body, which will lead to poor reverse peeling. However, the present invention pre-cuts the incompletely dried anisotropic conductive glue layer, so that the release film layer has multiple anisotropic conductive glue layers, and pre-cut grooves exist between the anisotropic conductive glue layers. After the oven treatment, the anisotropic conductive glue layer is completely dried, and then the anisotropic conductive glue film is cut at the pre-cut grooves. This allows the tool to cut directly on the release film without contacting the glue, which can greatly reduce the frequency of tool cleaning and the use of organic cleaning agents, making the production process more environmentally friendly.

[0009] Preferably, the pre-treated anisotropic conductive adhesive solution comprises dispersing / stirring the raw materials of the anisotropic conductive adhesive solution uniformly, mixing them, and filtering them to obtain a uniform solution.

[0010] More preferably, the raw materials of the anisotropic conductive adhesive solution include all raw materials applicable to anisotropic conductive adhesive, including but not limited to acrylic system, epoxy system, and polyurethane system.

[0011] More preferably, the dispersion / stirring method includes but is not limited to ultrasonic dispersion, high-speed homogenization emulsification dispersion, planetary stirring plus three-roll mill dispersion, and mix tank stirring.

[0012] In order to facilitate subsequent pre-cutting in the present invention, it is necessary to ensure that the raw material liquid is mixed uniformly and coated uniformly.

[0013] Preferably, the first drying and the second drying process include passing the coated anisotropic conductive adhesive through 3 to 9 ovens in sequence at a speed of 2 to 10 m / min.

[0014] More preferably, the length of each oven section is 2 to 8 m.

[0015] More preferably, the number of oven sections passed through in the first drying process is less than or equal to the number of oven sections passed through in the second drying process.

[0016] More preferably, the oven temperature for the first drying process is 50-70°C, and the oven temperature for the second drying process is 70-80°C.

[0017] More preferably, the solvent volatilization rate after the first drying is 60-90%; and the solvent volatilization rate after the second drying is 95-99.8%.

[0018] When the solvent volatilization rate before pre-cutting is 70-90% after the first drying, the shape of the anisotropic conductive adhesive layer after pre-cutting is ensured not to change significantly. At the same time, it is convenient for the blade group in the pre-cutting process to remove the anisotropic conductive adhesive in the pre-cut groove, which is also convenient for subsequent cutting. In addition, due to the presence of the pre-cut groove, the solvent in the anisotropic conductive adhesive layer is more easily volatilized during the second drying process, shortening the heating time and / or reducing the heating temperature, thereby saving energy.

[0019] The solvent is dried at a constant speed during the first drying process, and is dried at a decreasing speed during the second drying process.

[0020] Preferably, the first drying and second drying processes pass through 6 drying ovens in total.

[0021] More preferably, the temperature of the third section oven ≥ the temperature of the second section oven > the temperature of the first section oven; the temperature of the sixth section oven ≥ the temperature of the fifth section oven ≥ the temperature of the fourth section oven.

[0022] More preferably, the first drying comprises passing the coated anisotropic conductive adhesive film through the first, second and third ovens in sequence, and the solvent volatilization rate of the anisotropic conductive adhesive layer after the first drying is 80-90%.

[0023] More preferably, the second drying comprises passing the coated anisotropic conductive adhesive film through the fourth, fifth, and sixth ovens in sequence, and the solvent volatilization rate of the anisotropic conductive adhesive layer after the second drying is 98-99.7%.

[0024] More preferably, the temperature of the first section oven is 50-60°C, the temperature of the second section oven is 60-65°C, the temperature of the third section oven is 65-70°C, the temperature of the fourth section oven is 70-75°C, the temperature of the fifth section oven is 70-75°C, and the temperature of the sixth section oven is 75-80°C.

[0025] Preferably, the first drying comprises passing the coated anisotropic conductive adhesive film through the first and second drying ovens in sequence, and the solvent volatilization rate of the anisotropic conductive adhesive layer after the first drying is 60-80%.

[0026] More preferably, the second drying comprises passing the coated anisotropic conductive adhesive film through the third to sixth drying ovens in sequence, and the solvent volatilization rate of the anisotropic conductive adhesive layer after the second drying is 97-99.8%.

[0027] More preferably, the temperature of the first section oven is 50-60°C, the temperature of the second section oven is 65-70°C, the temperature of the third section oven is 65-70°C, the temperature of the fourth section oven is 70-75°C, the temperature of the fifth section oven is 75-80°C, and the temperature of the sixth section oven is 75-80°C.

[0028] Preferably, the pre-cutting process includes passing the incompletely dried anisotropic conductive adhesive film through a pre-cutting device including an upper roller and a lower roller.

[0029] Further preferably, the upper roller is provided with N groups of annular blades, the spacing between each group of annular blades is equal to the width of the anisotropic conductive colloid layer in the film; each group of annular blades consists of two blades, and the spacing between the two blades is equal to the width of the pre-cut groove.

[0030] More preferably, the spacing between each set of annular blades is 0.6-4 mm, and the spacing between two blades is 0.02-0.2 mm.

[0031] Preferably, the depth of the pre-cut grooves between the anisotropic conductive adhesive films after pre-cutting is ±1 μm of the thickness of the ACF adhesive.

[0032] More preferably, the thickness of the anisotropic conductive colloid layer is 30 to 50 μm.

[0033] Preferably, the shape of the pre-cut groove is a rectangle or an isosceles trapezoid.

[0034] More preferably, when the shape of the pre-cut groove is an isosceles trapezoid, the angle formed by the side of the pre-cut groove and the plane of the release film layer is 80-95°.

[0035] More preferably, at the side where the release film layer contacts the anisotropic conductive colloid layer, the width of the release film layer is greater than the width of the anisotropic conductive colloid layer, and the distance therebetween is 0.01-0.1 mm.

[0036] During pre-cutting, the anisotropic conductive colloid layer contacts the upper roller blade, and the incompletely dried anisotropic conductive colloid layer is peeled off from the release film layer through the rotation and extrusion of the upper roller and the lower roller.

[0037] Preferably, the pre-cut anisotropic conductive adhesive film includes a release film layer and N±1 anisotropic conductive colloid layers uniformly arranged thereon.

[0038] The anisotropic conductive colloid layer of the present invention is not completely dried during pre-cutting. If the solvent volatility is too high during cutting, on the one hand, the colloid may remain on the pre-cutting tool, resulting in large monomer blocks that are difficult to clean. On the other hand, the colloid has a strong cohesive force, and during pre-cutting, the colloid may move relative to the PET layer, causing misalignment. If the solvent volatility is too low during cutting, the colloid has excessive fluidity, which is not conducive to positioning the pre-cutting tool and forming the pre-cut grooves. Furthermore, the incompletely dried anisotropic conductive colloid layer obtained by pre-cutting can be reprocessed and reused as a recycled raw material, saving costs and protecting the environment.

[0039] Further preferably, the pre-cut anisotropic conductive adhesive film includes a release film layer and N+1 anisotropic conductive colloid layers uniformly arranged thereon.

[0040] Preferably, in the cutting process, a tool is used to cut the release film layer from the middle of the pre-cut groove, and the tool does not contact the anisotropic conductive colloid layer.

[0041] Preferably, during the coating process, there is a distance between the edge of the release film layer and the edge of the anisotropic conductive adhesive solution, and the distance is 0.01 to 5 mm.

[0042] Preferably, the width of the release film layer in the cut anisotropic conductive adhesive film is greater than the width of the anisotropic conductive colloid layer.

[0043] More preferably, the difference between the width of the release film layer and the width of the anisotropic conductive colloid layer is 0.02-0.2 mm.

[0044] The invention also discloses an anisotropic conductive adhesive film for improving adhesive overflow.

[0045] Preferably, the reverse peeling failure rate of the anisotropic conductive adhesive film for improving adhesive overflow is 0.05-0.2%.

[0046] The present invention uses raw materials that can be applied to anisotropic conductive adhesives, including but not limited to acrylic systems, epoxy systems, and polyurethane systems, combined with the preparation method of the anisotropic conductive adhesive film with improved adhesive overflow of the present invention to achieve the above-mentioned reverse peeling defect rate.

[0047] It is worth noting that the present invention can adjust the thickness of the anisotropic conductive adhesive layer, the distance between each set of blades, and the distance between two blades in each set of blades according to needs to set the length, width, and thickness of the cut anisotropic conductive adhesive film.

[0048] It should be noted that the anisotropic conductive adhesive film of the present invention is not limited to the raw materials of the present invention, and can be composed of any raw material that can be used as anisotropic conductive adhesive film.

[0049] It is worth noting that the coating, first drying, pre-cutting, second drying, cutting, and winding steps of the present invention can be performed by an integrated device or in separate steps.

[0050] Compared with the prior art, the present invention has the following beneficial effects:

[0051] 1. The present invention improves the preparation method of anisotropic conductive adhesive film with poor adhesive overflow by pre-cutting an incompletely dried anisotropic conductive colloid layer so that a plurality of anisotropic conductive colloid layers are formed on the release film layer, and pre-cut grooves are formed between the anisotropic conductive colloid layers; after oven treatment, the anisotropic conductive colloid layer is completely dried, and then the anisotropic conductive adhesive film is cut at the pre-cut grooves, so that the cutter does not need to contact the colloid and can directly cut the release film, which can greatly reduce the frequency of tool cleaning, reduce the use of organic cleaning agents, and increase the tool life, making the production process more environmentally friendly.

[0052] 2. In the preparation method of the anisotropic conductive adhesive film with improved adhesive overflow of the present invention, the first drying and second drying processes are set to constant speed drying and reduced speed drying respectively. In constant speed drying, the solvent moves quickly and freely to the surface of the colloidal solution and leaves, and the solvent volatilization rate is relatively high at this time; in reduced speed drying, the surface of the colloidal solution is dried, and the movement of the internal solvent gradually slows down.

[0053] 3. In the preparation method of the anisotropic conductive adhesive film with improved glue overflow of the present invention, the incompletely dried anisotropic conductive colloid layer is pre-cut after the first drying, which can avoid colloid residue and / or relative movement between the colloid and the PET layer. In addition, compared with directly cutting the completely dried anisotropic conductive colloid layer, the glue on the blade is easier to clean.

[0054] 4. The preparation method of the anisotropic conductive adhesive film with improved glue overflow of the present invention is that the width of the release film layer in the anisotropic conductive adhesive film after cutting is greater than the width of the anisotropic conductive colloid layer. During the reel winding process, the overflowed glue is prevented from adhering to the inner side of the reel disk and the side of the film body, avoiding reverse peeling problems.

[0055] 5. The preparation method of the anisotropic conductive adhesive film with improved adhesive overflow of the present invention is simple, environmentally friendly, and can be produced on a large scale. BRIEF DESCRIPTION OF THE DRAWINGS

[0056] Figure 1 This is a flow chart for preparing anisotropic conductive adhesive film with improved adhesive overflow in Example 1 of the present invention.

[0057] Figure 2 1 is a top view of the pre-cut anisotropic conductive adhesive film in Example 1 of the present invention.

[0058] Figure 3 1 is a side view of the pre-cut anisotropic conductive adhesive film in Example 1 of the present invention.

[0059] Figure 4 1 is a side view of the anisotropic conductive adhesive film after cutting in Example 1 of the present invention.

[0060] Figure 5 1 is a side view of the anisotropic conductive adhesive film after being cut and the anisotropic conductive adhesive film after being rolled up in Example 9 of the present invention.

[0061] Figure 6 1 is a side view of the anisotropic conductive adhesive film after being cut and the anisotropic conductive adhesive film after being rolled up in Example 10 of the present invention.

[0062] Figure 7 1 is a side view of the anisotropic conductive adhesive film after being cut and the anisotropic conductive adhesive film after being rolled up in Example 11 of the present invention.

[0063] Figure 8 Schematic diagram of the anisotropic conductive adhesive film during the cutting process in Comparative Example 1 of the present invention.

[0064] Figure 9 1 is a side view of the anisotropic conductive adhesive film after cutting and the anisotropic conductive adhesive film after rolling in Comparative Example 1 of the present invention.

[0065] 1. Release film layer, 2. Anisotropic conductive colloid layer, 21. Partially dried anisotropic conductive film, 21', first anisotropic conductive colloid layer, 21", N+1th anisotropic conductive colloid layer, 3. Coating liquid, 4. Upper roller, 5. Lower roller, 6. A set of blades, 7. A single blade. DETAILED DESCRIPTION

[0066] The following are specific embodiments of the present invention, which further describe the technical solutions of the present invention, but the present invention is not limited to these embodiments.

[0067] Example 1

[0068] In the anisotropic conductive adhesive film of this embodiment for improving adhesive overflow, the release film layer 1 has a thickness of 75 μm, a width of 2.16 mm, and a length of 300 μm; the anisotropic conductive colloid layer 2 has a thickness of 35 μm and a width of 2 mm; the spacing between the two pre-cut anisotropic conductive colloid layers (i.e., the width of the pre-cut groove) is 0.16 mm and the depth is 35.1 μm; the side surface of the pre-cut groove is rectangular.

[0069] The length of each oven used in this embodiment is 6 m.

[0070] The preparation of anisotropic conductive adhesive film with improved adhesive overflow includes: dispersing conventional acrylic conductive adhesive raw materials on the market in sequence, mixing and filtering, and preparing a coating liquid 3 with a pore size of 20 μm.

[0071] Coating liquid 3 was then added from the coating head and evenly applied to the surface of the release film layer 1, with a distance of 0.08 mm between the edge of the release film layer 1 and the edge of the coating liquid 3. The film then passed through the first to third drying ovens at a speed of 6 m / min. The temperature of the first oven was 56°C, with a solvent volatilization rate of 10%. The temperature of the second oven was 62°C, and the temperature of the third oven was 67°C. These were all constant-rate drying stages, allowing the solvent to freely migrate to the liquid surface and evaporate, with a solvent volatilization rate of 85%.

[0072] A partially dried anisotropic conductive adhesive film 21 is placed in a pre-cutting device comprising an upper roller 4 and a lower roller 5. The upper roller 4 is equipped with N sets of blades 6 arranged evenly, with a spacing of 3 mm between blades 6 in each set, and a spacing of 0.16 mm between blades 7 in each set. During pre-cutting, the partially dried anisotropic conductive adhesive layer 21 comes into contact with the upper roller blades 7. The rotation and extrusion of the upper and lower rollers 4 and 5 peels a portion of the partially dried anisotropic conductive adhesive layer 21 from the release film layer 1, resulting in N+1 strips of anisotropic conductive adhesive layer 2, from the first strip 21' to the N+1 strip 21".

[0073] The pre-cut anisotropic conductive adhesive film is continued to pass through the 4th to 6th ovens at a speed of 6 m / min. The temperature of the 4th oven is 72°C, the temperature of the 5th oven is 74°C, and the temperature of the 6th oven is 78°C. The 4th to 6th ovens are a speed reduction drying stage, and the solvent volatilization rate is 99.5%, so that the anisotropic conductive adhesive film is hardened.

[0074] The completely dried anisotropic conductive adhesive film 2 is cut. During the cutting process, a cutter is used to cut the release film layer 1 from the middle of the pre-cut groove, and the cutter does not need to contact the anisotropic conductive colloid layer 2.

[0075] The preparation flow chart of the anisotropic conductive adhesive film for improving the adhesive overflow problem in this embodiment is as follows: Figure 1 As shown, the top view of the pre-cut anisotropic conductive film is as follows Figure 2 As shown, the side view of the pre-cut anisotropic conductive film is as follows Figure 3 As shown, the side view of the anisotropic conductive film after cutting is as follows Figure 4 As shown. Figure 1-4 As shown, in this embodiment, the thickness of the anisotropic conductive colloid layer 2 is different from that of the release film layer 1. During the reel winding process, the ACF colloid may overflow outward due to the action of force. In this embodiment, due to the presence of the pre-cut groove, there is a difference in width between the release film layer and the anisotropic conductive colloid layer. The overflowed glue will not stick to the inner side of the reel disk and the side of the film body, and it is not easy to cause reverse peeling failure. In addition, during cutting, the tool does not need to contact the colloid and can directly cut the release film layer 1, which can greatly reduce the frequency of tool cleaning and the use of organic cleaning agents, making the production process more environmentally friendly.

[0076] The anisotropic conductive adhesive film with improved adhesive overflow prepared in this embodiment was subjected to performance tests. The reverse peeling failure rate was 0.10%; the on-resistance was 0.02Ω, and the insulation resistance was 9.5×10 9 Ω, and the bonding strength is 1100gf / cm.

[0077] Example 2

[0078] In the anisotropic conductive adhesive film of this embodiment for improving adhesive overflow, the release film layer 1 has a thickness of 75 μm, a width of 1.66 mm, and a length of 300 m; the anisotropic conductive colloid layer 2 has a thickness of 35 μm and a width of 1.5 mm; the spacing between the two pre-cut anisotropic conductive colloid layers (i.e., the width of the pre-cut groove) is 0.16 mm and the depth is 35.1 μm; and the side surfaces of the pre-cut groove are rectangular.

[0079] Compared with Example 1, the difference is that the preparation of the anisotropic conductive adhesive film with improved adhesive overflow includes:

[0080] After the ACA film leaves the second oven section, it undergoes pre-slotting. The first oven section is set at 57°C with a solvent evaporation rate of 11%. The second oven section is set at 68°C with a solvent evaporation rate of 70%, all at a constant drying rate. After pre-slotting, the film undergoes a second drying process, with oven temperatures of 69°C in the third oven section, 72°C in the fourth oven section, 76°C in the fifth oven section, and 78°C in the sixth oven section. The fourth through sixth oven sections are a decreasing drying process, with a solvent evaporation rate of 99.4%, which hardens the ACA film.

[0081] In this embodiment, the outer surface of the partially dried anisotropic conductive adhesive film 21 is already substantially solidified when pre-cut, resulting in minimal shape change after pre-cutting. This allows for easy partial removal of the partially dried anisotropic conductive adhesive film 21, and the blade is easily cleaned. Furthermore, the pre-cut grooves create a gap between the width of the release film and the anisotropic conductive adhesive layer, ensuring that any excess adhesive during reel winding, as required by the present invention, does not adhere to the inner side of the reel or the sides of the film itself, and is less likely to cause reverse peeling problems.

[0082] The anisotropic conductive adhesive film with improved adhesive overflow prepared in this embodiment was subjected to performance tests. The reverse peeling failure rate was 0.11%; the on-resistance was 0.02Ω, and the insulation resistance was 9×10 9 Ω, and the bonding strength is 1050gf / cm.

[0083] Example 3

[0084] In the anisotropic conductive adhesive film of this embodiment for improving adhesive overflow, the release film layer 1 has a thickness of 75 μm, a width of 3.66 mm, and a length of 300 m; the anisotropic conductive colloid layer 2 has a thickness of 35 μm and a width of 3.5 mm; the spacing between the two pre-cut anisotropic conductive colloid layers (i.e., the width of the pre-cut groove) is 0.16 mm and the depth is 35.0 μm; and the side surface of the pre-cut groove is rectangular.

[0085] Compared with Example 1, the difference is that the preparation of the anisotropic conductive adhesive film with improved adhesive overflow includes:

[0086] After leaving the third oven, the ACA film is pre-grooved. The first oven is set at 58°C, with a solvent volatilization rate of 12%. The second and third ovens are set at 65°C, with a solvent volatilization rate of 86%. The pre-grooved ACA film then passes through ovens 4-6 at a speed of 6 m / min. The fourth oven is set at 72°C, the fifth at 74°C, and the sixth at 78°C. The fourth and sixth ovens are used for a decreasing-speed drying phase, with a solvent volatilization rate of 99.4%, which hardens the ACA film.

[0087] In this embodiment, the outer surface of the anisotropic conductive colloid layer 2 is essentially solidified when the partially dried anisotropic conductive adhesive film 21 is pre-cut, so the shape does not change significantly after pre-cutting. This allows for easy partial removal of the partially dried anisotropic conductive adhesive film 21, and the blade is easy to clean. Furthermore, the pre-cut grooves create a gap between the width of the release film layer and the anisotropic conductive colloid layer. This prevents excess adhesive from adhering to the inner side of the reel or the sides of the film during reel winding, thus minimizing reverse peeling problems.

[0088] The anisotropic conductive adhesive film with improved adhesive overflow prepared in this embodiment was subjected to performance tests. The reverse peeling failure rate was 0.11%; the on-resistance was 0.02Ω, and the insulation resistance was 9.1×10 9 Ω, and the bonding strength is 1070gf / cm.

[0089] Example 4

[0090] In the anisotropic conductive adhesive film of this embodiment for improving adhesive overflow, the release film layer 1 has a thickness of 75 μm, a width of 3.16 mm, and a length of 300 m; the anisotropic conductive colloid layer 2 has a thickness of 35 μm and a width of 3 mm; the spacing between the two pre-cut anisotropic conductive colloid layers (i.e., the width of the pre-cut groove) is 0.16 mm and the depth is 35.1 μm; and the side surface of the pre-cut groove is rectangular.

[0091] In this embodiment, the method described in Example 1 was used to prepare an incompletely dried anisotropic conductive adhesive film 21 with a solvent volatility of 84% and an anisotropic conductive adhesive film finished product with a solvent volatility of 99.2%.

[0092] The outer surface of the anisotropic conductive adhesive film 21 that was not completely dried during pre-cutting has already essentially solidified, and its shape does not change significantly after pre-cutting. At this point, the partially dried anisotropic conductive adhesive film 21 is easily removed, and the blade is easy to clean. During the reel reeling process, any excess adhesive that adheres to the inner surface of the reel or the sides of the film itself will not adhere to the reel, and reverse peeling problems are unlikely to occur.

[0093] The anisotropic conductive adhesive film with improved adhesive overflow prepared in this embodiment was subjected to a performance test, and the reverse peeling failure rate was 0.12%.

[0094] The pre-cut anisotropic conductive adhesive that is not completely dried can be recycled and turned into a second-class raw material through a regeneration method, and anisotropic conductive adhesive film can be prepared according to the method of Example 1.

[0095] The performance of the second type of anisotropic conductive adhesive film with improved adhesive overflow was tested, and the reverse peeling failure rate was 0.16%.

[0096] Example 5

[0097] In the anisotropic conductive adhesive film for improving adhesive overflow in this embodiment, the release film layer 1 has a thickness of 75 μm, a width of 2.16 mm, and a length of 300 m; the anisotropic conductive colloid layer 2 has a thickness of 35 μm and a width of 2 mm; the spacing between the anisotropic conductive colloid layers (i.e., the width of the pre-cut groove) is 0.16 mm and the depth is 35.1 μm; and the side surface of the pre-cut groove is rectangular.

[0098] Compared with Example 1, the difference is that the preparation of the anisotropic conductive adhesive film with improved adhesive overflow includes:

[0099] After the anisotropic conductive film leaves the oven in Section 4, the pre-cut grooves are pre-cut.

[0100] In this embodiment, the solvent evaporation rate of the anisotropic conductive adhesive film 21, which was not completely dried during pre-cutting, was 92%. At this point, the anisotropic conductive adhesive layer 2 was essentially solidified, and its shape remained essentially unchanged after pre-cutting. The solvent evaporation rate of the finished anisotropic conductive adhesive film was 99.4%. This met the requirements of the present invention, preventing excess adhesive from adhering to the inner side of the reel or the sides of the film itself during reel winding, and thus preventing reverse peeling problems. However, the anisotropic conductive adhesive film was relatively hard during pre-cutting, making it difficult to cut and increasing the difficulty of cleaning the blade.

[0101] The anisotropic conductive adhesive film with improved adhesive overflow prepared in this embodiment was subjected to performance tests. The reverse peeling failure rate was 0.15%; the on-resistance was 0.04Ω, and the insulation resistance was 9.0×10 9 Ω, and the bonding strength is 990gf / cm.

[0102] Example 6

[0103] In the anisotropic conductive adhesive film for improving adhesive overflow in this embodiment, the release film layer 1 has a thickness of 75 μm, a width of 2.16 mm, and a length of 300 m; the anisotropic conductive colloid layer 2 has a thickness of 35 μm and a width of 2 mm; the spacing between the anisotropic conductive colloid layers (i.e., the width of the pre-cut groove) is 0.16 mm and the depth is 35.1 μm; and the side surface of the pre-cut groove is rectangular.

[0104] Compared with Example 1, the difference is that the preparation of the anisotropic conductive adhesive film with improved adhesive overflow includes:

[0105] After the anisotropic conductive film leaves the oven in Section 5, the pre-cut grooves are pre-cut.

[0106] In this embodiment, the solvent evaporation rate of the anisotropic conductive adhesive film 21, which was not completely dried during pre-cutting, was 94%. At this point, the anisotropic conductive adhesive layer 2 was essentially solidified, and its shape remained essentially unchanged after pre-cutting. The solvent evaporation rate of the finished anisotropic conductive adhesive film was 99.5%. This met the requirements of the present invention, preventing excess adhesive from adhering to the inner side of the reel or the sides of the film during reel winding, and also reducing the risk of reverse peeling problems. However, the anisotropic conductive adhesive film is relatively hard during pre-cutting, making it difficult to remove and increasing the difficulty of cleaning the blade.

[0107] The anisotropic conductive adhesive film with improved adhesive overflow prepared in this embodiment was subjected to performance tests. The reverse peeling failure rate was 0.17%; the on-resistance was 0.04Ω, and the insulation resistance was 8.7×10 9 Ω, and the bonding strength is 980gf / cm.

[0108] Example 7

[0109] In the anisotropic conductive adhesive film for improving adhesive overflow in this embodiment, the release film layer 1 has a thickness of 75 μm, a width of 2.16 mm, and a length of 300 m; the anisotropic conductive colloid layer 2 has a thickness of 35 μm and a width of 2 mm; the depth of the anisotropic conductive colloid layer is 34.9 μm; the side surface of the pre-cut groove is nearly rectangular, and the spacing between each set of annular blades is 0.16 mm.

[0110] Compared with Example 1, the difference is that the preparation of the anisotropic conductive adhesive film with improved adhesive overflow includes:

[0111] After the anisotropic conductive film leaves the first section of the oven, the pre-cut grooves are pre-cut.

[0112] In this embodiment, the solvent volatility of the anisotropic conductive adhesive film 21, which was not completely dried during pre-cutting, was 10%, resulting in relatively high fluidity. This caused the anisotropic conductive adhesive layer 2 to flow to the sides during pre-cutting, resulting in a distance between the anisotropic conductive adhesive layer 2 and the edge of the release film layer 1 of less than 0.16 mm. The solvent volatility of the finished anisotropic conductive adhesive film was 99.2%. Due to the pre-set distance, most of the excess adhesive did not adhere to the inner side of the reel or the sides of the film during reel winding. However, some adhesive still adhered, resulting in a certain degree of reverse peeling failure.

[0113] The anisotropic conductive adhesive film with improved adhesive overflow prepared in this embodiment was subjected to performance tests. The reverse peeling failure rate was 0.34%; the on-resistance was 0.03Ω, and the insulation resistance was 8.9×10 9 Ω, and the bonding strength is 1000gf / cm.

[0114] Example 8

[0115] In the anisotropic conductive adhesive film for improving adhesive overflow in this embodiment, the release film layer 1 has a thickness of 75 μm, a width of 2.16 mm, and a length of 300 m; the anisotropic conductive colloid layer 2 has a thickness of 35 μm and a width of 2 mm; the spacing between the anisotropic conductive colloid layers (i.e., the width of the pre-cut groove) is 0.16 mm and the depth is 35.1 μm; and the side surface of the pre-cut groove is rectangular.

[0116] Compared with Example 1, the difference is that the preparation of the anisotropic conductive adhesive film with improved adhesive overflow includes:

[0117] After the anisotropic conductive adhesive film leaves the sixth oven, that is, after the anisotropic conductive colloid layer 2 is completely dried, the pre-cutting of the pre-cut grooves is performed.

[0118] In this embodiment, the presence of the pre-cut groove creates a difference in width between the release film layer and the anisotropic conductive colloid layer. This ensures that any excess adhesive during reel winding, as required by the present invention, does not adhere to the inner side of the reel disc or the sides of the film itself, thus minimizing reverse peeling problems. However, in this embodiment, since the anisotropic conductive colloid layer 2 is completely dry, the solvent volatilization rate of the finished anisotropic conductive adhesive film is 99.1%, making pre-cutting difficult and the blade cleaning difficult.

[0119] The anisotropic conductive adhesive film with improved adhesive overflow prepared in this embodiment was subjected to performance tests. The reverse peeling failure rate was 0.19%; the on-resistance was 0.03Ω, and the insulation resistance was 8.8×10 9 Ω, and the bonding strength is 990gf / cm.

[0120] Example 9

[0121] In the finished anisotropic conductive adhesive film with improved adhesive overflow obtained in this embodiment, the release film layer 1 has a thickness of 75 μm, a width of 2.16 mm, and a length of 300 m; the thickness of the anisotropic conductive colloid layer 2 is 35 μm, and the width of its lower contact surface (connecting with the release film layer) is 2 mm; the spacing at the junction of the two pre-cut anisotropic conductive colloid layers (i.e., the width of the pre-cut groove) is 0.16 mm, and the depth is 35.1 μm; the side surface of the pre-cut groove is a right isosceles trapezoid, and the angle formed by the side of the pre-cut groove and the plane of the release film layer 1 in the pre-cut groove is 95°.

[0122] Compared with Example 1, the difference is that the preparation of the anisotropic conductive adhesive film with improved adhesive overflow includes:

[0123] There is an angle difference between the blade 7 at the upper roller 4 and the upper roller 4. The left blade 7 in each set of blades 6 forms an outer angle of 85° with the upper roller 4. The right blade 7 in the set of blades 6 is axially symmetrical with the left blade 7. Figure 5 1 is a side view of the anisotropic conductive adhesive film after being cut and the anisotropic conductive adhesive film after being rolled up in this embodiment.

[0124] In this embodiment, an incompletely dried anisotropic conductive adhesive film 21 with a solvent volatilization rate of 85% and an anisotropic conductive adhesive film finished product with a solvent volatilization rate of 99.5% are obtained.

[0125] In this embodiment, due to the presence of the pre-cut groove, there is a difference in width between the release film layer and the anisotropic conductive colloid layer. This satisfies the requirements of the present invention that any glue overflowing during the reel winding process will not stick to the inner side of the reel disk and the side of the film body, and is less likely to cause reverse peeling problems.

[0126] The anisotropic conductive adhesive film with improved adhesive overflow prepared in this embodiment was subjected to performance tests. The reverse peeling failure rate was 0.13%; the on-resistance was 0.02Ω, and the insulation resistance was 8.9×10 9 Ω, and the bonding strength is 960gf / cm.

[0127] Example 10

[0128] In the anisotropic conductive adhesive film for improving adhesive overflow in this embodiment, the release film layer 1 has a thickness of 75 μm, a width of 2.2 mm, and a length of 300 m; the thickness of the anisotropic conductive colloid layer 2 is 35 μm, and the width of its lower contact surface is 2 mm; the spacing at the junction of the two pre-cut anisotropic conductive colloid layers (i.e., the width of the pre-cut groove) is 0.2 mm, and the depth is 35.1 μm; the side surface of the pre-cut groove is an inverted isosceles trapezoid, and the angle formed between the side of the pre-cut groove and the plane of the release film layer 1 in the pre-cut groove is 80°.

[0129] Compared with Example 1, the difference is that the preparation of the anisotropic conductive adhesive film with improved adhesive overflow includes:

[0130] There is an angle difference between the blade 7 at the upper roller 4 and the upper roller 4. The left blade 7 in each set of blades 6 forms an angle of 80° with the upper roller 4. The right blade 7 in the set of blades 6 is axially symmetrical with the left blade 7. Figure 6 1 is a side view of the anisotropic conductive adhesive film after being cut and the anisotropic conductive adhesive film after being rolled up in this embodiment.

[0131] In this embodiment, a partially dried anisotropic conductive adhesive film 21 with a solvent volatilization rate of 85% and a finished anisotropic conductive adhesive film with a solvent volatilization rate of 99.6% are obtained.

[0132] In this embodiment, due to the presence of the pre-cut groove, there is a difference in width between the release film layer and the anisotropic conductive colloid layer, and the distance is large enough to meet the requirements of the present invention. The glue overflowing during the reel winding process will not stick to the inner side of the reel disk and the side of the film body, and it is not easy to cause reverse peeling problems.

[0133] The anisotropic conductive adhesive film with improved adhesive overflow prepared in this embodiment was subjected to performance tests. The reverse peeling failure rate was 0.15%; the on-resistance was 0.02Ω, and the insulation resistance was 8.9×10 9 Ω, and the bonding strength is 950gf / cm.

[0134] Example 11

[0135] In the anisotropic conductive adhesive film for improving adhesive overflow in this embodiment, the release film layer 1 has a thickness of 75 μm, a width of 2.06 mm, and a length of 300 m; the thickness of the anisotropic conductive colloid layer 2 is 35 μm, and the width of its lower contact surface is 2 mm; the spacing at the junction of the two pre-cut anisotropic conductive colloid layers (i.e., the width of the pre-cut groove) is 0.04 mm, and the depth is 35.1 μm; the side surface of the pre-cut groove is an inverted isosceles trapezoid, and the angle formed between the side of the pre-cut groove and the plane of the release film layer 1 in the pre-cut groove is 70°. Figure 7 1 is a side view of the anisotropic conductive adhesive film after being cut and the anisotropic conductive adhesive film after being rolled up in this embodiment.

[0136] In this embodiment, a partially dried anisotropic conductive adhesive film 21 with a solvent volatilization rate of 85% and a finished anisotropic conductive adhesive film with a solvent volatilization rate of 99.6% are obtained.

[0137] Although there is a pre-cut groove in this embodiment, which creates a gap in width between the release film layer and the anisotropic conductive colloid layer, the reserved distance is small; and there is a large width difference between the upper and lower surfaces of the anisotropic conductive colloid layer 2, resulting in instability and displacement. As a result, some of the glue that overflows during the reel winding process will stick to the inner side of the reel disk and the side of the film body, resulting in a certain degree of reverse peeling failure.

[0138] The anisotropic conductive adhesive film with improved adhesive overflow prepared in this embodiment was subjected to performance tests. The reverse peeling failure rate was 0.37%; the on-resistance was 0.03Ω, and the insulation resistance was 8.9×10 9 Ω, and the bonding strength is 910gf / cm.

[0139] Comparative Example 1

[0140] In the anisotropic conductive adhesive film of this comparative example, the release film layer 1 has a thickness of 75 μm, a width of 2 mm, and a length of 300 m; the anisotropic conductive colloid layer 2 has a thickness of 35 μm and a width of 2 mm.

[0141] Compared with Example 1, the difference is that the coating liquid 3 is evenly coated on the surface of the release film layer 1, and after being completely dried, it is cut with a knife and rolled up.

[0142] Schematic diagram of the anisotropic conductive film during the cutting process Figure 8 As shown, the side view of the anisotropic conductive film after cutting and the anisotropic conductive film after rolling is as shown Figure 9 As shown in the figure, during the reel winding process, the ACF glue will overflow due to the force, and the overflowed glue will stick to the inner side of the reel plate and the side of the film body, thereby causing poor reverse peeling.

[0143] The anisotropic conductive adhesive film with improved adhesive overflow prepared in this comparative example was subjected to performance tests. The reverse peeling failure rate was 0.52%; the on-resistance was 0.04Ω, and the insulation resistance was 8.1×10 9 Ω, and the bonding strength is 900gf / cm.

[0144] In summary, the preparation method of the anisotropic conductive adhesive film of the present invention is used to improve the glue overflow problem. Due to the presence of the pre-cut groove, there is a gap in the width of the release film layer and the anisotropic conductive colloid layer, which meets the requirements of the present invention. The glue overflowing during the reel winding process will not stick to the inner side of the reel disk and the side of the film body, and it is not easy to cause reverse peeling problems; and the pre-cutting process is convenient for removing part of the anisotropic conductive colloid layer before the anisotropic conductive colloid layer is completely dry, and it is also convenient to clean the blade; in addition, in the final cutting process, only the release film layer needs to be cut, and there is no need to frequently clean the tool, which is more environmentally friendly and cost-saving.

[0145] The specific embodiments described herein are merely illustrative of the spirit of the present invention. Persons skilled in the art may make various modifications, additions, or substitutions to the described specific embodiments without departing from the spirit of the present invention or exceeding the scope of the appended claims.

Claims

1. A method for preparing anisotropic conductive adhesive film with improved adhesive overflow, characterized in that: The preparation method comprises: The pre-treated anisotropic conductive adhesive solution is coated, dried for the first time, pre-cut, dried for the second time, cut, and rolled; The pre-treated anisotropic conductive adhesive solution comprises dispersing / stirring each raw material of the anisotropic conductive adhesive solution, mixing the raw materials, and filtering to obtain a uniform solution; Pre-cutting includes passing the incompletely dried anisotropic conductive adhesive film through a pre-cutting device including an upper roller and a lower roller to remove part of the anisotropic conductive colloid layer on the release film layer to form a pre-cut groove; The upper roller is provided with N groups of annular blades, and the spacing between each group of annular blades is equal to the width of the anisotropic conductive colloid layer in the incompletely dried anisotropic conductive adhesive film; each group of annular blades consists of two blades, and the spacing between the two blades is equal to the width of the pre-cut groove; The width of the release film layer in the cut anisotropic conductive adhesive film is greater than the width of the anisotropic conductive colloid layer.

2. The preparation method according to claim 1, characterized in that The pre-cut anisotropic conductive adhesive film includes a release film layer and N±1 anisotropic conductive colloid layers uniformly arranged thereon.

3. The preparation method according to claim 1, characterized in that The first drying and second drying processes include passing the coated anisotropic conductive adhesive film through 3 to 9 drying ovens in sequence at a speed of 2 to 10 m / min.

4. The preparation method according to claim 1 or 3, characterized in that The number of oven sections passed through in the first drying process is less than or equal to the number of oven sections passed through in the second drying process.

5. The preparation method according to claim 1 or 3, characterized in that The solvent volatilization rate of the anisotropic conductive adhesive layer after the first drying is 60-90%; the solvent volatilization rate of the anisotropic conductive adhesive layer after the second drying is 95-99.8%.

6. The preparation method according to claim 1, characterized in that In the cutting process, a cutter is used to cut the release film layer from the middle of the pre-cut groove, and the cutter does not contact the anisotropic conductive colloid layer.

7. The preparation method according to claim 1, characterized in that The difference between the width of the release film layer and the width of the anisotropic conductive colloid layer is 0.02-0.2 mm.

8. An anisotropic conductive adhesive film for improving adhesive overflow, characterized in that: The anisotropic conductive adhesive film with improved adhesive overflow is prepared by the preparation method according to any one of claims 1 to 7.

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