ACF (anisotropic conductive film) adhesive film based on modified PVB (polyvinyl butyral) resin, ACF bonding assembly and preparation method of ACF bonding assembly
By modifying PVB resin and optimizing the process, combined with nano-reinforcing particles and epoxy resin, the problem of insufficient conductive particle capture rate of PVB resin ACF film was solved, achieving high efficiency and stable conductivity and reliability, making it suitable for the connection of electronic devices.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-12-30
- Publication Date
- 2026-03-27
AI Technical Summary
Existing PVB resin ACF films have shortcomings in terms of conductive particle capture rate, resulting in poor conductivity stability and long-term reliability. Furthermore, existing methods for improving this are costly or have complex processes, making them difficult to apply on a large scale.
By modifying and optimizing the process of PVB resin, and combining it with nano-reinforcing particles, epoxy resin and conductive particles, a composite modified PVB resin is formed, which improves the fixation effect of conductive particles in the film. A cationic initiator is used for the reaction, and a toughening agent is used to improve the toughness. The film is then coated on a carrier film substrate to form an ACF film.
It significantly improves the conductive particle capture rate and reliability of ACF film, with a particle capture rate of up to 90%, excellent aging performance, tensile strength of up to 20MPa, and good aging resistance.
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Abstract
Description
Technical Field
[0001] This invention belongs to the field of conductive adhesive film technology, specifically relating to ACF adhesive film based on modified PVB resin, ACF bonding components and their preparation methods. Background Technology
[0002] Anisotropic conductive film (ACF) is a key material in electronic device manufacturing for achieving precise connections between chips and substrates, display panels and driving circuits, and its performance directly affects the quality and reliability of electronic products. The core function of ACF is to achieve good conductivity in the vertical direction while maintaining insulation in the horizontal direction, thereby ensuring precise electrical connections between electronic components. The distribution and trapping efficiency of conductive particles in the ACF film are among the key factors determining its performance.
[0003] Currently, the capture rate of conductive particles faces numerous challenges in the preparation of composite PVB resin ACF films. On the one hand, the interaction between the traditional film resin matrix and conductive particles is relatively weak, leading to the displacement, aggregation, or detachment of some conductive particles during processing and use. These particles cannot be stably fixed within the film, thus affecting the conductive stability and long-term reliability of the ACF film. On the other hand, existing methods for improving particle capture rates, such as adding complex additives or employing special processing techniques, often result in increased costs, excessive process complexity, or environmental unfriendliness, limiting their large-scale application.
[0004] PVB resin (polyvinyl butyral resin) has a certain application foundation in the field of adhesive films due to its good flexibility, adhesion, and impact resistance. However, how to significantly improve the capture rate of conductive particles in ACF adhesive films through reasonable modification and application, thereby improving the overall performance of ACF adhesive films, is an important problem that urgently needs to be solved in the field of electronic materials. Summary of the Invention
[0005] To address the problems mentioned above, this invention provides a method for preparing ACF based on modified PVB resin. This method first modifies the PVB resin and optimizes the preparation process, enabling the ACF film to efficiently and stably capture conductive particles, improving the fixation effect of conductive particles in the film, and thus enhancing the conductivity and reliability of the ACF film.
[0006] To achieve the above objectives, the present invention adopts the following technical solution: a method for preparing an ACF film based on modified PVB resin, comprising the following steps: S1, PVB resin modification: 10-60 parts by weight of PVB resin and 5-50 parts by weight of a compound containing active reactive groups are sequentially added to 50-500 parts by weight of an organic solvent. The mixture is reacted at 50-100 °C for 2-4 hours. Then, 1-20 parts by weight of nano-reinforcing particles are added, and the mixture is stirred and reacted for another 1-2 hours to form a composite modified PVB resin. S2. Preparation of anisotropic conductive adhesive film: The composite modified PVB resin, epoxy resin, cationic initiator, toughening agent, and conductive particles are mixed in a mass ratio of (5-30):(20-60):(0.1-10):(1-10):(10-30) and stirred at 300-500 rpm for 0.5-2 hours to obtain a mixed adhesive solution. The mixed adhesive solution is then uniformly coated onto a carrier film substrate and dried to remove the solvent, resulting in an anisotropic conductive film (ACF) with a thickness of 5-20 μm.
[0007] Further improvements to the preparation method of ACF films based on modified PVB resin: Preferably, the compound containing an active reactive group in step S1 is a compound containing a carboxyl group, a hydroxyl group, or an epoxy group.
[0008] Preferably, the compound containing the active reactive group in step S1 is acrylic acid, ethylene glycol, or epichlorohydrin.
[0009] Preferably, with reference to the glass transition temperature of PVB resin, the reaction temperature in step S1 is designed to be 60-80℃.
[0010] Preferably, the organic solvent in step S1 is one or more of acetone, methyl ethyl ketone, methyl isobutyl ketone, benzene, toluene, xylene, methanol, ethanol, and ethyl acetate.
[0011] Preferably, the nano-reinforcing particles in step S1 are one or more of nano-calcium oxide, nano-titanium dioxide, nano-zinc oxide, nano-silica, and nano-alumina.
[0012] Preferably, the epoxy resin in step S2 is one or more of the following: bisphenol A type epoxy resin, halogenated bisphenol A type epoxy resin, bisphenol S epoxy resin, bisphenol F epoxy resin, alicyclic epoxy resin, aliphatic-alicyclic epoxy resin, aromatic-alicyclic epoxy resin, glycerol epoxy resin, ethylene glycol epoxy resin, phenolic epoxy resin, amino epoxy resin, unsaturated epoxy resin, acrylic epoxy resin, dicyclopentadiene epoxy resin, polybutadiene epoxy resin, organotitanium epoxy resin, organosilicon epoxy resin, phenoxy epoxy resin, and fluorinated epoxy resin.
[0013] Preferably, the epoxy resin in step S2 is one or more of the following: bisphenol A type epoxy resin, halogenated bisphenol A type epoxy resin, bisphenol S epoxy resin, bisphenol F epoxy resin, alicyclic epoxy resin, aliphatic-alicyclic epoxy resin, aromatic-alicyclic epoxy resin, glycerol epoxy resin, ethylene glycol epoxy resin, phenolic epoxy resin, amino epoxy resin, unsaturated epoxy resin, acrylic epoxy resin, dicyclopentadiene epoxy resin, polybutadiene epoxy resin, organotitanium epoxy resin, organosilicon epoxy resin, phenoxy epoxy resin, and fluorinated epoxy resin.
[0014] Preferably, the cationic initiator in step S2 is one or more of the following: aromatic sulfonium salt, aromatic diazonium salt, iodonium salt, phosphonium salt, and selenium salt.
[0015] Preferably, the cationic initiator in step S2 is one or more of aromatic sulfonium salts, aromatic diazonium salts, iodonium salts, phosphonium salts, and selenium salts, as they are suitable for use as cationic initiators due to their excellent reaction at low temperatures and long service life.
[0016] Preferably, the conductive particles in step S2 are polymer microspheres with a metal layer coated on the surface and a particle size of 0.5-5 μm.
[0017] Preferably, the conductive particles in step S2 are polystyrene microspheres with gold, silver, or nickel plating on the surface, preferably gold-plated polystyrene microspheres, and preferably have a particle size of 1-3 μm.
[0018] Preferably, the toughening agent in step S2 is one or more of liquid rubber or core-shell rubber.
[0019] Preferably, the toughening agent in step S2 is one or more of the following: liquid polysulfide rubber, liquid acrylate rubber, liquid polybutadiene rubber, nitrile rubber, ethylene propylene rubber and styrene-butadiene rubber, styrene-isoprene-styrene block copolymer, styrene-butadiene-styrene block copolymer, styrene-isoprene / butadiene-styrene block copolymer, styrene-ethylene / butene-styrene block copolymer, styrene-ethylene / propylene-styrene block copolymer, styrene-ethylene / butene / styrene-styrene block copolymer, and core-shell rubber.
[0020] Preferably, the carrier film substrate in step S2 is a polymer substrate with a layered structure coated with a treatment agent. The mixed adhesive is uniformly coated on the carrier film substrate and then placed in an oven at 50-70°C for 5-15 minutes to remove the solvent, thereby obtaining an ACF adhesive film bonding material with a thickness of 5-20 μm.
[0021] Preferably, the polymer substrate is PET (Poly Ethylene Terephthalate), PTFE (Polytetrafluoroethylene), OPP (Oriented Polypropylene), PMP (Poly-4-methylpentene-1), etc.; the treatment agent is silicone, etc.; the mixed adhesive is uniformly coated on the carrier film substrate by a coating machine or coating device.
[0022] The second objective of this invention is to provide an ACF film prepared by the above-mentioned method for preparing ACF film based on modified PVB resin.
[0023] The second objective of this invention is to provide an ACF bonding assembly prepared from the above-mentioned ACF film, comprising the following steps: attaching one side of the ACF film to the electrode of a first electronic component, placing a second electronic component on the ACF film circuit connection material according to a pressing process, and using a pressure connector to heat and press from above the second electronic component to achieve circuit connection between the electrode of the first electronic component and the electrode of the second electronic component, thereby forming an ACF bonding assembly.
[0024] As a further improvement to the ACF bonding component: Preferably, the first electronic component is IZO-coated glass with an IZO (Indium Zinc Oxide) film coated on a glass substrate, or SiNx-coated glass with a SiNx (Silicon Nitride) film coated on a glass substrate. The second electronic component is COF (Chip On Film), IC (Integrated Circuit), or a chip.
[0025] The advantages of this invention compared to the prior art are as follows: (1) This invention provides a method for preparing an ACF film based on modified PVB resin, specifically including the following steps: PVB resin modification; PVB resin (polyvinyl butyral resin) is synthesized by butyralization reaction of polyvinyl alcohol and butyral. Due to incomplete reaction, its structural formula (1) contains acetyl and hydroxyl groups. Its thermal, mechanical properties and melt viscosity are controlled by adjusting the degree of polymerization or the ratio of acetal group (butyral group), acetyl group, hydroxyl group and other structures.
[0026]
[0027] Chemical formula (1)
[0028] PVB itself possesses excellent flexibility, film-forming properties, transparency, adhesion, and weather resistance. It was chosen as the base resin for ACF primarily to utilize its flexibility and adhesion, which are crucial for absorbing stress (such as differences in thermal expansion coefficients) and providing reliable bonding during the bonding process. PVB molecules contain a large number of hydroxyl groups. Added compounds with reactive groups react chemically with these hydroxyl groups under heating conditions, introducing carboxyl functional groups into the PVB resin molecular chain. This enhances reactivity, improves compatibility, strengthens interfacial bonding, and imparts specific properties. The introduced nano-reinforcing particles improve the mechanical strength, impact resistance (toughening), and heat resistance of the film, helping to maintain the stability of the bonding points under high and low temperature cycles or mechanical impacts, preventing the breakage of conductive pathways, and improving the mechanical properties (modulus, strength, toughness), thermal stability, and dimensional stability of the composite material. Referring to the glass transition temperature of PVB resin, the modification reaction temperature of polyvinyl butyral resin in step S1 is designed to be 50–100℃, more preferably 60–80℃. Within this range, flowability during compression can be suppressed, and the trapping ability of conductive particles can be improved.
[0029] Anisotropic conductive film (ACF) is prepared by mixing composite modified PVB with epoxy resin, conductive particles, etc., and then coating and drying the mixture. Composite modified PVB and epoxy resin serve as the main resins; an initiator catalyzes the cationic ring-opening polymerization of epoxy groups; a toughening agent further improves the toughness of the cured film, resisting impact and stress cracking; conductive particles provide a conductive path along the Z-axis (thickness direction) while maintaining insulation in the XY plane (in-plane direction).
[0030] (2) This invention provides a simple, batch-producible method for modifying PVB resin to improve the particle capture rate of ACF films and solve the problem of insufficient conductive particle capture. By modifying PVB resin using simple and efficient process parameters, the particle capture rate and reliability of the film are greatly improved. The raw materials used in this invention are inexpensive and readily available on the market. The PVB resin modification process is simple and easy to industrialize. The film particle capture rate can reach 90%, and it exhibits excellent aging performance.
[0031] (3) The present invention provides an ACF bonded component based on the above modified PVB resin. The particle capture performance of the ACF bonded component reaches 90%, the double 85 aging performance is ≤5%, and the tensile strength performance reaches 20MPa. Detailed Implementation
[0032] The following describes examples, specifically relating to the preparation of anisotropic conductive films of ACF containing modified polyvinyl butyral resin. These conductive films are used to prepare ACF bonded components, and their particle trapping properties, reactivity, conductivity, mechanical properties, and aging resistance are evaluated. It should be noted that the present invention is not limited to these examples, and all other embodiments obtained by those skilled in the art without inventive effort are within the scope of protection of this invention.
[0033] Example 1
[0034] This invention provides a method for preparing an ACF film based on modified PVB resin, specifically including the following steps: S1, PVB resin modification: 50 parts of PVB resin (Mowital™ B60H, Kuraray) were added to 200 parts of toluene and stirred until dissolved. Then 10 parts of acrylic acid (butyl acrylate BA, BASF) were added, and the mixture was reacted at 70°C for 3 hours. 2 parts of nano-titanium dioxide (CR-828, Kono) were added to the above reaction system, and the mixture was stirred and reacted for another 1.5 hours to obtain composite modified PVB resin A. Preparation of S2 and ACF film: Take 20 parts of the above-mentioned composite modified PVB resin A, 35 parts of bisphenol A epoxy resin (EP828, JER Corporation), 1 part of cationic initiator (SI-100, Sanshin Chemical), 3 parts of core-shell rubber toughening agent (Kane Ace™ MX 551, Kaneka Chemical), and 1 part of silane coupling agent (KBM403, Shin-Etsu Chemical), and then disperse 20 parts of conductive particles (AUL704, Sekisui Chemical). Stir at 500 rpm for 0.5 h to obtain a mixed adhesive solution. Coat the mixed adhesive solution onto a PET film using a coating machine, and dry it in a 70°C oven to obtain a 12 μm thick ACF film 1.
[0035] Example 2
[0036] This invention provides a method for preparing an ACF film based on modified PVB resin, specifically including the following steps: PVB resin modification: 50 parts of PVB resin (Mowital™ B60H, Kuraray) were added to 200 parts of toluene and stirred to dissolve. Then, 10 parts of ethylene glycol (Dow Chemical) were added, and the mixture was reacted at 65°C for 3.5 hours to introduce hydroxyl functional groups into the PVB resin molecular chain. 2 parts of nano-titanium dioxide (CR-828, Kono) were added to the above reaction system, and the reaction was continued for 1.5 hours to obtain composite modified PVB resin B. Preparation of ACF film: Take 20 parts of the above-mentioned composite modified PVB resin solution, 35 parts of bisphenol A epoxy resin (EP828, JER Corporation), 1 part of cationic initiator (SI-100, Sanshin Chemical), 3 parts of core-shell rubber toughening agent (Kane Ace™ MX 551, Kaneka Chemical), 1 part of silane coupling agent (KBM403, Shin-Etsu Chemical), and then disperse 20 parts of conductive particles (AUL704, Sekisui Chemical) and mix. Stir at 300 rpm for 2 h to obtain a mixed adhesive solution. Coat the mixed adhesive solution onto a PET film using a coating machine and dry it in a 70°C oven to obtain a 12 μm thick ACF film 2.
[0037] Example 3
[0038] This invention provides a method for preparing an ACF film based on modified PVB resin, specifically including the following steps: PVB resin modification: 50 parts of PVB resin (Mowital™ B60H, Kuraray) were added to 200 parts of toluene and stirred to dissolve. Then, 10 parts of epichlorohydrin (Dow Chemical) were added, and the mixture was reacted at 70°C for 3 hours to introduce epoxy functional groups onto the PVB resin molecular chain. 2 parts of nano-titanium dioxide (CR-828, Kono) were added to the above reaction system, and the reaction was continued with stirring for 1.5 hours to obtain composite modified PVB resin C. Preparation of ACF film: Take 20 parts of the above-mentioned composite modified PVB resin solution, 35 parts of bisphenol A epoxy resin (EP828, JER Corporation), 1 part of cationic initiator (SI-100, Sanshin Chemical), 3 parts of core-shell rubber toughening agent (Kane Ace™ MX 551, Kaneka Chemical), 1 part of silane coupling agent (KBM403, Shin-Etsu Chemical), and then disperse 20 parts of conductive particles (AUL704, Sekisui Chemical) and mix. Stir at 400 rpm for 1 h to obtain a mixed adhesive solution. Coat the mixed adhesive solution onto a PET film using a coating machine and dry it in a 70°C oven to obtain a 12 μm thick ACF film 3.
[0039] Comparative Example 1
[0040] This invention provides a method for preparing an ACF film based on PVB resin, specifically including the following steps: S1, Unmodified PVB Resin Solution: 60 parts of PVB resin (Mowital™ B60H, Kuraray) were added to 200 parts of toluene and stirred to dissolve. 2 parts of nano-titanium dioxide (CR-828, Kono) were added, and the reaction was continued for 1.5 hours to obtain composite PVB resin D; S2. Preparation of ACF film: Take 10 parts of the composite modified PVB resin A prepared in Example 1, 10 parts of composite PVB resin D, 35 parts of bisphenol A epoxy resin (EP828, JER Corporation), 1 part of cationic initiator (SI-100, Sanshin Chemical), 3 parts of core-shell rubber toughening agent (Kane Ace™ MX 551, Kaneka Chemical), and 1 part of silane coupling agent (KBM403, Shin-Etsu Chemical), and then disperse 20 parts of conductive particles (AUL704, Sekisui Chemical) and mix. Stir at 400 rpm for 1 h to obtain a mixed adhesive solution. Coat the mixed solution onto a PET film using a coating machine and dry it in a 70°C oven to obtain a 12 μm thick ordinary ACF film 1.
[0041] Comparative Example 2
[0042] This invention provides a method for preparing an ACF film based on PVB resin, specifically including the following steps: S1, Unmodified PVB Resin Solution: 60 parts of PVB resin (Mowital™ B60H, Kuraray) were added to 200 parts of toluene and stirred to dissolve. 2 parts of nano-titanium dioxide (CR-828, Kono) were added, and the reaction was continued for 1.5 hours to obtain composite PVB resin D; S2, ACF film preparation: Take 20 parts of the above composite PVB resin solution, 35 parts of bisphenol A epoxy resin (EP828, JER Corporation), 1 part of cationic initiator (SI-100, Sanshin Chemical), 3 parts of core-shell rubber toughening agent (Kane Ace™ MX 551, Kaneka Chemical), 1 part of silane coupling agent (KBM403, Shin-Etsu Chemical), and add 20 parts of conductive particles (AUL704, Sekisui Chemical). Stir at 400 rpm for 1 h to obtain a mixed adhesive solution. Coat the mixed adhesive solution onto a PET film using a coating machine and dry it in a 70°C oven to obtain a 12μm thick ordinary ACF film 2.
[0043] Comparative Example 3
[0044] This invention provides a method for preparing an ACF film, specifically including the following steps: Preparation of ACF film: A composition of 55 parts bisphenol A epoxy resin (EP828, JER Corporation), 1 part cationic initiator (SI-100, Sanshin Chemical), 3 parts core-shell rubber toughening agent (Kane Ace™ MX 551, Kaneka Chemical), and 1 part silane coupling agent (KBM403, Shin-Etsu Chemical) was mixed with 20 parts conductive particles (AUL704, Sekisui Chemical) and stirred at 400 rpm for 1 h to obtain a mixed adhesive solution. The mixed adhesive solution was coated onto a PET film using a coating machine and then dried in a 70°C oven to obtain a 12 μm thick ACF film 3.
[0045] Example 4
[0046] This embodiment provides a method for preparing an ACF bonding component, which specifically includes the following steps: The ACF films prepared in Examples 1-3 and Comparative Examples 1-3 were cut (1.5 mm wide). One side of the cut ACF film was temporarily attached to the electrode of the conductive glass substrate (ITO pattern, glass thickness 0.7 mm). The IC chip (bump size: 30×85 μm, pitch: 50 μm, gold bump height: h=15 μm) was placed on the ACF film circuit connection material according to the pressing process. The IC chip was heated and pressed from the top using a pressure connector. 50 μm thick PTFE was used as a buffer material. The heating tool (1.5 mm wide) was used to press the IC chip at 150°C, 3 MPa, and for 15 seconds (tool speed 10 mm / sec, stage temperature 40°C) to achieve the circuit connection between the electrode of the first electronic component and the electrode of the second electronic component, forming an ACF bonding assembly.
[0047] Performance testing: (1) Test method Particle capture rate test: The distribution of conductive particles in the ACF film was statistically analyzed using a Leica DM750 M metallurgical microscope and image analysis technology.
[0048] Reactivity test: The reaction peak of 10 mg sample was measured by using a DSC differential calorimeter (DSC 214 Polyma) from -40 °C to 250 °C at a rate of 10 °C / min, with the temperature increasing from -40 °C to 250 °C.
[0049] Conductivity test: The maximum and minimum values of the on-resistance when a 1mA current is passed through the ACF bonding assembly pressed at 150℃ were measured using an Agilent digital multimeter (Keysight U1253B) with a four-terminal generator.
[0050] Mechanical performance testing: The tensile strength and elongation at break of the ACF film were tested using the Shimadzu AGS-X universal testing tensile tester.
[0051] Aging resistance test: After aging the ACF film in an environment of 85°C and 85% humidity for 1000 hours, the conductivity and mechanical properties are tested again, and the rate of change is calculated.
[0052] (2) Test results
[0053] The performance test results of the ACF bonding components assembled with ACF films in Examples 1-3 and Comparative Examples 1-3 are shown in Table 1 below: Table 1 Performance Tests of ACF Bonded Components
[0054] Table 1 shows that the particle capture rate of the ACF bonding assembly assembled from the ACF film of Example 1 reached 94%, indicating good particle capture effect. The reaction peak temperature of the ACF film was 110℃, showing good low-temperature reactivity. Under the pressing condition of 150℃, the maximum on-resistance was 1.5Ω and the minimum was 0.7Ω, indicating good conductivity. The tensile strength was 20MPa and the elongation at break was 35%, indicating good mechanical properties. After aging the ACF film in an environment of 85℃ and 85% humidity for 1000 hours, the conductivity and mechanical properties were tested again. The resistivity change rate was less than 5%, the tensile strength remained above 18MPa, and the elongation at break remained above 30%, indicating excellent aging resistance.
[0055] Table 1 shows that the particle capture rate of the ACF bonding assembly assembled from the ACF film of Example 2 reached 92%, indicating good particle capture effect. The reaction peak temperature of the ACF film was 108℃, showing good low-temperature reactivity. Under the pressing condition of 150℃, the maximum on-resistance was 1.5Ω and the minimum was 0.7Ω, indicating good conductivity. The tensile strength was 20MPa and the elongation at break was 33%, indicating good mechanical properties. After aging the ACF film in an environment of 85℃ and 85% humidity for 1000 hours, the conductivity and mechanical properties were tested again. The resistivity change rate was less than 5%, the tensile strength remained above 18MPa, and the elongation at break remained above 30%, indicating excellent aging resistance.
[0056] Table 1 shows that the particle capture rate of the ACF bonding assembly assembled from the ACF film of Example 3 reached 91%, indicating good particle capture effect. The reaction peak temperature of the ACF film was 113℃, showing good low-temperature reactivity. Under the pressing condition of 150℃, the maximum on-resistance was 1.5Ω and the minimum was 0.7Ω, indicating good conductivity. The tensile strength was 21MPa and the elongation at break was 33%, indicating good mechanical properties. After aging the ACF film in an environment of 85℃ and 85% humidity for 1000 hours, the conductivity and mechanical properties were tested again. The resistivity change rate was less than 5%, the tensile strength remained above 18MPa, and the elongation at break remained above 30%, indicating excellent aging resistance.
[0057] Table 1 shows that the particle capture rate of the ACF bonding assembly assembled from the ACF film of Comparative Example 1 reached 83%, indicating poor particle capture performance. The reaction peak temperature of the ACF film was 110℃. Under the pressure bonding condition at 150℃, the maximum on-resistance was 1.6Ω and the minimum was 0.8Ω. The tensile strength was 18MPa, and the elongation at break was 30%. After aging the ACF film in an environment of 85℃ and 85% humidity for 1000 hours, the conductivity and mechanical properties were tested again. The resistivity change rate was greater than 20%, the tensile strength decreased to 17MPa, and the elongation at break decreased to 22%.
[0058] Table 1 shows that the particle capture rate of the ACF bonding assembly assembled from the ACF film of Comparative Example 2 reached 75%, indicating poor particle capture performance. The reaction peak temperature of the ACF film was 110℃. Under the pressure bonding condition at 150℃, the maximum on-resistance was 1.6Ω and the minimum was 0.8Ω. The tensile strength was 18MPa, and the elongation at break was 30%. After aging the ACF film in an environment of 85℃ and 85% humidity for 1000 hours, the conductivity and mechanical properties were tested again. The resistivity change rate was greater than 20%, the tensile strength decreased to 12MPa, and the elongation at break decreased to 18%.
[0059] Table 1 shows that the particle capture rate of the ACF bonding assembly assembled from the ACF film of Comparative Example 3 reached 68%, indicating poor particle capture performance. The reaction peak temperature of the ACF film was 110℃. Under the pressure bonding condition at 150℃, the maximum on-resistance was 1.6Ω and the minimum was 0.8Ω. The tensile strength was 16MPa, and the elongation at break was 28%. After aging the ACF film in an environment of 85℃ and 85% humidity for 1000 hours, the conductivity and mechanical properties were tested again. The resistivity change rate was greater than 20%, the tensile strength decreased to 10MPa, and the elongation at break decreased to 15%.
[0060] In summary, the preparation method of the present invention first modifies the PVB resin in a specific way and optimizes the preparation process, so that the ACF film can efficiently and stably capture conductive particles, improve the fixation effect of conductive particles in the film, and thus improve the conductivity and reliability of the ACF film.
[0061] Those skilled in the art should understand that the above descriptions are merely several specific embodiments of the present invention, and not all embodiments. It should be noted that many modifications and improvements can be made by those skilled in the art, and all modifications or improvements not exceeding the scope of the claims should be considered within the protection scope of the present invention.
Claims
1. A method for preparing an ACF film based on modified PVB resin, characterized in that, Includes the following steps: S1, PVB resin modification: 10-60 parts by weight of PVB resin and 5-50 parts by weight of a compound containing active reactive groups are sequentially added to 50-500 parts by weight of an organic solvent. The mixture is reacted at 50-100 °C for 2-4 hours. Then, 1-20 parts by weight of nano-reinforcing particles are added, and the mixture is stirred and reacted for another 1-2 hours to form a composite modified PVB resin. S2. Preparation of anisotropic conductive adhesive film: The composite modified PVB resin, epoxy resin, cationic initiator, toughening agent, and conductive particles are mixed in a mass ratio of (5-30):(20-60):(0.1-10):(1-10):(10-30) and stirred at 300-500 rpm for 0.5-2 hours to obtain a mixed adhesive solution. The mixed adhesive solution is then uniformly coated onto a carrier film substrate and dried to remove the solvent, resulting in an anisotropic conductive film (ACF) with a thickness of 5-20 μm.
2. The method for preparing an ACF film based on modified PVB resin according to claim 1, characterized in that, The compound containing an active reactive group mentioned in step S1 is a compound containing a carboxyl group, a hydroxyl group, or an epoxy group.
3. The method for preparing an ACF film based on modified PVB resin according to claim 1, characterized in that, The organic solvent mentioned in step S1 is one or more of acetone, methyl ethyl ketone, methyl isobutyl ketone, benzene, toluene, xylene, methanol, ethanol, and ethyl acetate; or the nano-reinforcing particles are one or more of nano-calcium oxide, nano-titanium dioxide, nano-zinc oxide, nano-silica, and nano-alumina.
4. The method for preparing ACF film based on modified PVB according to claim 1, characterized in that, The epoxy resin mentioned in step S2 is one or more of the following: bisphenol A type epoxy resin, halogenated bisphenol A type epoxy resin, bisphenol S epoxy resin, bisphenol F epoxy resin, alicyclic epoxy resin, aliphatic-alicyclic epoxy resin, aromatic-alicyclic epoxy resin, glycerol epoxy resin, ethylene glycol epoxy resin, phenolic epoxy resin, amino epoxy resin, unsaturated epoxy resin, acrylic epoxy resin, dicyclopentadiene epoxy resin, polybutadiene epoxy resin, organotitanium epoxy resin, organosilicon epoxy resin, phenoxy epoxy resin, and fluorinated epoxy resin.
5. The method for preparing an ACF film based on modified PVB resin according to claim 1, characterized in that, The cationic initiator in step S2 is one or more of aromatic sulfonium salts, aromatic diazonium salts, iodonium salts, phosphonium salts, and selenium salts; or, the conductive particles are polymer microspheres with a metal layer coated on the surface and a particle size of 0.5-5 μm.
6. The method for preparing an ACF film based on modified PVB resin according to claim 1, characterized in that, The toughening agent mentioned in step S2 is one or more of the following: liquid polysulfide rubber, liquid acrylate rubber, liquid polybutadiene rubber, nitrile rubber, ethylene propylene rubber and styrene-butadiene rubber, styrene-isoprene-styrene block copolymer, styrene-butadiene-styrene block copolymer, styrene-isoprene / butadiene-styrene block copolymer, styrene-ethylene / butene-styrene block copolymer, styrene-ethylene / propylene-styrene block copolymer, styrene-ethylene / butene / styrene-styrene block copolymer, and core-shell rubber.
7. The method for preparing an ACF film based on modified PVB resin according to claim 1, characterized in that, In step S2, the carrier film substrate is a polymer substrate with a layered structure coated with a treatment agent. The mixed adhesive is uniformly coated on the carrier film substrate and then placed in an oven at 50-70°C for 5-15 minutes to remove the solvent, thereby obtaining an ACF adhesive film bonding material with a thickness of 5-20 μm.
8. An ACF film prepared by the method for preparing an ACF film based on modified PVB resin according to any one of claims 1-7.
9. An ACF bonding component prepared from the ACF film according to any one of claims 8, characterized in that, The process includes the following steps: attaching one side of the ACF film to the electrode of the first electronic component, placing the second electronic component on the ACF film circuit connection material according to the pressing process, and using a pressure connector to heat and press from above the second electronic component to achieve circuit connection between the electrodes of the first electronic component and the electrodes of the second electronic component, forming an ACF bonding assembly.
10. The ACF bonding assembly prepared from the ACF film according to claim 9, characterized in that, The first electronic component is IZO coated glass with an indium zinc oxide film coated on a glass substrate, or SiNx coated glass with a silicon nitride film coated on a glass substrate; the second electronic component is a flip-chip or a chip.