Adhesive composition, adhesive film for circuit connection, and method for manufacturing connection structure

Abstract

An adhesive composition that contains (A) an epoxy resin and (B) a curing agent, in which a pyridinium salt is included as the (B) component, the pyridinium salt includes a pyridinium cation and an anion, the pyridinium cation has a benzyl group at the 1-position and an electron-attracting group at the 2-position, the benzyl group has an electron-donating group, and the anion is B(C6F5)4 - or B(C6H3(CF3)2)4 - (wherein the CF3 group is substituted at the 3- and 5-positions of a phenyl group).

Description

[Technical Field]

[0001] This disclosure relates to an adhesive composition, an adhesive film for circuit connection, and a method for manufacturing a connection structure. [Background technology]

[0002] As a circuit connection material that heats and pressurizes opposing circuit components and electrically connects electrodes in the direction of pressurization, for example, anisotropically conductive circuit connection adhesive films in which conductive particles are dispersed in the adhesive are known (see, for example, Patent Documents 1 to 4 below). Such adhesive films are widely used for connecting liquid crystal display (LCD) panels to tape carrier packages (TCP) or chip-on-flex (COF) on which semiconductors that drive the LCD are mounted, or for electrical connections between printed circuit boards and TCPs or COFs.

[0003] Recently, even when semiconductors are mounted face-down directly onto LCD panels or printed circuit boards, flip-chip mounting, which is advantageous for thin-film and narrow-pitch connections, has been adopted as an alternative to the conventional wire bonding method. Here too, anisotropically conductive adhesive films for circuit connections are used as the circuit connection material. [Prior art documents] [Patent Documents]

[0004] [Patent Document 1] Japanese Unexamined Patent Publication No. 60-191228 [Patent Document 2] Japanese Patent Application Publication No. 1-251787 [Patent Document 3] Japanese Patent Application Publication No. 7-90237 [Patent Document 4] Japanese Patent Publication No. 2019-104869 [Overview of the Initiative] [Problems that the invention aims to solve]

[0005] In recent years, due to the need for lighter displays and improved design, display bezels have become narrower, and there is a growing demand for products with virtually no bezels, such as smartphones. Furthermore, the space available for mounting electronic components such as driver ICs and TCPs for display operation has also narrowed, and in displays with particularly narrow bezels, electronic components are sometimes mounted very close to the display area. If the heat resistance of the display material is low, the heat generated during the mounting of electronic components can cause malfunctions in the display material. Therefore, there is a need for adhesive compositions that can cure at low temperatures. Additionally, from the perspective of improving manufacturing efficiency, there is a demand for adhesive compositions that can cure at even lower temperatures.

[0006] Furthermore, in recent years, market demands for panel quality reliability have been increasing. Therefore, achieving excellent connection resistance is essential.

[0007] Therefore, the present disclosure aims to provide an adhesive composition that can be cured at a low temperature (115°C) and that can achieve excellent connection resistance. The present disclosure also aims to provide an adhesive film for circuit connection, a connection structure, and a method for manufacturing the connection structure using the adhesive composition. Furthermore, the present disclosure aims to provide a pyridinium salt used in the adhesive composition. [Means for solving the problem]

[0008] One aspect of this disclosure includes the following [1] to [7]. [1] (A) epoxy resin and (B) hardener are included, The aforementioned component (B) includes a pyridinium salt, The pyridinium salt comprises a pyridinium cation and an anion. The pyridinium cation has a benzyl group at position 1 and an electron-withdrawing group at position 2, The benzyl group has an electron-donating group, The aforementioned anion is B(C6F5)4- , or B(C6H3(CF3)2)4 - An adhesive composition in which the CF3 group is substituted at the 3,5 position of the phenyl group. [2] The adhesive composition according to [1], further containing conductive particles. A circuit connection adhesive film having a region formed by the adhesive composition described in [3] [1] or [2]. [4] comprising a first region containing a first adhesive component and a second region adjacent to the first region containing a second adhesive component, A circuit connection adhesive film in which one or both of the first region and the second region are formed by the adhesive composition described in [1] or [2]. [5] A first circuit member having a first electrode, A second circuit member having a second electrode, A connecting portion is provided between the first circuit member and the second circuit member, and electrically connects the first electrode and the second electrode to each other. Equipped with, A connection structure comprising the connection portion including a cured product of the circuit connection adhesive film described in [3] or [4]. [6] A method for manufacturing a connection structure, comprising the steps of interposing a circuit connection adhesive film according to [3] or [4] between a first circuit member having a first electrode and a second circuit member having a second electrode, and then heat-pressing the first circuit member and the second circuit member to electrically connect the first electrode and the second electrode to each other. [7] A pyridinium salt comprising a pyridinium cation and an anion, The pyridinium cation has a benzyl group at position 1 and an electron-withdrawing group at position 2, The benzyl group has an electron-donating group, The aforementioned anion is B(C6F5)4 - , or B(C6H3(CF3)2)4 - A pyridinium salt in which the CF3 group is substituted at the 3,5 positions of the phenyl group. [Effects of the Invention]

[0009] This disclosure provides an adhesive composition that can be cured at a low temperature (115°C) and achieve excellent connection resistance. Furthermore, this disclosure provides an adhesive film for circuit connections, a connection structure, and a method for manufacturing the connection structure using the adhesive composition. Finally, this disclosure provides a pyridinium salt used in the adhesive composition. [Brief explanation of the drawing]

[0010] [Figure 1] This is a schematic cross-sectional view showing one embodiment of an adhesive film for circuit connections. [Figure 2] This is a schematic cross-sectional view showing one embodiment of an adhesive film for circuit connections. [Figure 3] This is a schematic cross-sectional view showing one embodiment of the connecting structure. [Figure 4] This is a schematic cross-sectional view showing the manufacturing method of the connecting structure shown in Figure 3. [Figure 5] This shows the DSC measurement results for the circuit connection adhesive film of Example 1. [Figure 6] This shows the DSC measurement results for the circuit connection adhesive film of Example 1. [Figure 7] This shows the DSC measurement results for the circuit connection adhesive film of Example 2. [Figure 8] This shows the DSC measurement results for the circuit connection adhesive film of Example 2. [Modes for carrying out the invention]

[0011] The embodiments of this disclosure will be described in detail below. However, this disclosure is not limited to the embodiments described below.

[0012] In the numerical ranges described herein, the upper or lower limits of the range may be replaced with the values ​​shown in the examples. Furthermore, the lower and upper limits of a numerical range may be arbitrarily combined with the lower or upper limits of other numerical ranges. In the notation "A~B" for a numerical range, the numbers A and B at both ends are included in the range as the lower and upper limits, respectively. In this specification, for example, "10 or more" means 10 and numbers greater than 10, and this applies even if the numbers are different. Similarly, for example, "10 or less" means 10 and numbers less than 10, and this applies even if the numbers are different. Also, unless otherwise specified, each component and material exemplified herein may be used alone or in combination of two or more. In this specification, the content of each component in a composition means the total amount of multiple substances present in the composition, unless otherwise specified, when multiple substances corresponding to each component exist in the composition. Furthermore, in this specification, "(meth)acrylate" means at least one of acrylate and its corresponding methacrylate. Furthermore, in this specification, "epoxy group" means a substituent that includes an epoxy group in its structure, such as a glycidyl group or a glycidyloxy group.

[0013] <Adhesive composition> The adhesive composition of this embodiment contains at least (A) epoxy resin (hereinafter also referred to as component (A)) and (B) curing agent (hereinafter also referred to as component (B)).

[0014] (Epoxy resin) The adhesive composition of this embodiment may contain, for example, an aromatic epoxy resin as component (A) in an amount of more than 90% by mass based on the total amount of component (A), and as the aromatic epoxy resin, it may also contain, for example, a polyfunctional epoxy resin having a skeleton represented by the following general formula (1) as (A1) (hereinafter also referred to as component (A1)).

[0015] [ka] In formula (1), X 1represents an oxygen atom, a sulfur atom, or an alkylene group having 1 to 10 carbon atoms. From the viewpoint of peel resistance, X 1 may be -CH2-.

[0016] (Epoxy resin) First, the component (A1) will be described.

[0017] As the component (A1), a polyfunctional epoxy resin represented by the following general formula (2) can be used. [Chemical formula] [In formula (2), X 1 represents an oxygen atom, a sulfur atom, or an alkylene group having 1 to 10 carbon atoms, R 1 and R 2 are substituents, each independently representing a glycidyl group or a glycidyloxy group, m and n each represent an integer of 1 to 7, and m + n is 2 or more.]

[0018] From the viewpoint of peel resistance, as the component (A1), a polyfunctional epoxy resin represented by the following general formula (3) can be used. [Chemical formula] [In formula (3), R 11 , R 12 , R 21 and R 22 each independently represent a hydrogen atom, a glycidyl group or a glycidyloxy group, and two or more of R 11 , R 12 , R 21 and R 22 are glycidyl groups or glycidyloxy groups.]

[0019] In formula (3), R 11 and R 22 are glycidyl groups or glycidyloxy groups, R 12 and R 21 may be hydrogen atoms, and R 11 , R 12 , R 21 and R22 All of them may be glycidyl groups or glycidyloxy groups.

[0020] (A1) The component can be a commercially available product such as "HP4700" and "HP4770" (both manufactured by DIC Corporation, product names).

[0021] (A1) Component (A1) can be used individually or in combination of two or more components.

[0022] The adhesive composition of this embodiment may contain a second aromatic epoxy resin other than component (A1) (hereinafter also referred to as component (A2)).

[0023] Examples of the second aromatic epoxy resin include bisphenol A type epoxy resin, bisphenol S type epoxy resin, phenol novolac type epoxy resin, cresol novolac type epoxy resin, bisphenol A novolac type epoxy resin, bisphenol F novolac type epoxy resin, tetramethylbisphenol A type epoxy resin, 3',4'-epoxycyclohexylmethyl-3,4-epoxycyclohexanecarboxylate (bi-7-oxabicyclo[4,1,0]heptane), 3,4-epoxycyclohexylmethyl (meth)acrylate, (3,3',4,4'-diepoxy)bicyclohexyl, dicyclopentadiene dimethanol diglycidyl ether, xylene novolac type glycidyl ether, etc. The second aromatic epoxy resin may be at least one selected from the group consisting of bisphenol A type epoxy resin, tetramethylbisphenol A type epoxy resin, dicyclopentadiene dimethanol diglycidyl ether, and xylene novolac type glycidyl ether.

[0024] From the viewpoint of more easily achieving excellent connection resistance even after HAST testing, a polyfunctional epoxy resin represented by the following general formula (7) (an epoxy resin having a trisphenolmethane structure) can be used as component (A2).

[0025] [ka] [In formula (7), R 71 , R 72 , and R 73 Each of these independently represents a hydrogen atom or an organic group, and R 71 , R 72 , and R 73 At least one of them represents an organic group having an epoxy group, R 74 R represents a hydrogen atom or an alkyl group. 75 [This represents a hydrogen atom or an organic group.]

[0026] R 71 , R 72 , and R 73 Examples of organic groups represented by include alkyl groups, alkyl ether groups, and alkenyl groups. These organic groups may have substituents. The number of carbon atoms in the organic group may be, for example, 2 or more, 3 or more, 8 or less, 6 or less, or 4 or less. 71 , R 72 , and R 73 At least one of these may be an organic group having a glycidyl group, or an organic group having a glycidyloxy group. 71 , R 72 , and R 73 These may be the same or different. 71 , R 72 , and R 73 From the viewpoint of more easily achieving excellent connection resistance even after HAST testing, these may be organic groups having a glycidyl group or organic groups having a glycidyloxy group.

[0027] R 74 If is an alkyl group, the alkyl group may be, for example, a methyl group, an ethyl group, or a propyl group. The alkyl group may have substituents. 74 From the viewpoint of more easily achieving excellent connection resistance even after HAST testing, hydrogen atoms may also be used.

[0028] R75 The organic group represented by may be, for example, an alkyl group, an alkyl ether group, or an alkenyl group. The organic group may have substituents. 75 From the viewpoint of more easily achieving excellent connection resistance even after HAST testing, it may be an alkyl group, an alkyl group with a substituent, or an alkyl group having a phenyl group. The phenyl group may have substituents, for example, an epoxy group, a glycidyl group, or a glycidyloxy group. 75 From the viewpoint of more easily achieving excellent connection resistance even after HAST testing, the alkyl group may be a phenyl group having a glycidyloxy group.

[0029] The number of epoxy groups in the polyfunctional epoxy resin represented by formula (7) may be 1 or more, 2 or more, or 3 or more, and may be 15 or less, 12 or less, or 10 or less.

[0030] The epoxy equivalent of the polyfunctional epoxy resin represented by formula (7) may be, for example, 100 to 300 g / eq or 150 to 250 g / eq. The epoxy equivalent refers to the value measured in accordance with JIS K7236.

[0031] The polyfunctional epoxy resin represented by formula (7) may specifically be a compound represented by the following formula (7A). [ka] [In equation (7A), n represents an integer between 1 and 3.]

[0032] The adhesive composition of this embodiment may contain an epoxy resin other than an aromatic epoxy resin as component (A). Examples of other epoxy resins include aliphatic epoxy resins and alicyclic epoxy resins. From the viewpoint of further improving low-temperature curing properties, component (A) may contain an alicyclic epoxy resin. Furthermore, from the viewpoint of easily achieving both low-temperature curing properties and good storage stability, component (A) does not need to contain an alicyclic epoxy resin.

[0033] The adhesive composition of this embodiment may contain resins other than epoxy resins, for example, it may contain a cationic polymerizable compound in addition to the epoxy resin. Examples of cationic polymerizable compounds include oxetane compounds. The adhesive composition of this embodiment may use a cationic polymerizable compound instead of epoxy resin. That is, another embodiment of the present disclosure contains a cationic polymerizable compound and a curing agent, the curing agent comprising a pyridinium salt, the pyridinium salt comprising a pyridinium cation and an anion, the pyridinium cation having a benzyl group at position 1 and an electron-withdrawing group at position 2, the benzyl group having an electron-donating group, and the anion being B(C6F5)4 - , or B(C6H3(CF3)2)4 - This is an adhesive composition in which the CF3 group is substituted at the 3,5 position of the phenyl group.

[0034] Examples of oxetane compounds include xylylenebisoxetane, 2-ethylhexyloxetane, 3-hydroxymethyl-3-methyloxetane, 3-hydroxymethyl-3-ethyloxetane, 3-hydroxymethyl-3-propyloxetane, 3-hydroxymethyl-3-n-butyloxetane, 3-hydroxymethyl-3-phenyloxetane, 3-hydroxymethyl-3-benzyloxetane, 3-hydroxyethyl-3-methyloxetane, 3-hydroxyethyl-3-ethyloxetane, and 3-hydroxyethyl- Examples include 3-propyloxetane, 3-hydroxyethyl-3-phenyloxetane, 3-hydroxypropyl-3-methyloxetane, 3-hydroxypropyl-3-ethyloxetane, 3-hydroxypropyl-3-propyloxetane, 3-hydroxypropyl-3-phenyloxetane, 3-hydroxybutyl-3-methyloxetane, 4,4'-bis[(3-ethyl-3-oxetanyl)methoxymethyl]biphenyl, and 3-ethyl-3{[(3-ethyloxetan-3-yl)methoxy]methyl}oxetane.

[0035] (A) The content of component (A) may be 10% by mass or more, 20% by mass or more, 30% by mass or more, or 35% by mass or more, based on the total mass of the adhesive composition, from the viewpoint of ensuring the curability of the adhesive composition. (A) The content of component (A) may be 70% by mass or less, 60% by mass or less, 50% by mass or less, or 45% by mass or less, based on the total mass of the adhesive composition, from the viewpoint of ensuring the formability of the adhesive composition.

[0036] The content of component (A) may be 50% by mass or more, 70% by mass or more, 80% by mass or more, 90% by mass or more, or 95% by mass or more, based on the total mass of the cationic polymerizable compound, from the viewpoint of making it easier to achieve a superior appearance even after the HAST test and from the viewpoint of having better adhesive properties. The content of component (A) in the cationic polymerizable compound may be substantially 100% by mass (a form in which the cationic polymerizable compound consists of component (A)).

[0037] The content of the polyfunctional epoxy resin represented by formula (7) in component (A) may be 20% by mass or more, 30% by mass or more, 40% by mass or more, or 45% by mass or more, based on the total mass of component (A), from the viewpoint of making it easier to achieve a superior appearance even after the HAST test and from the viewpoint of having better adhesive properties. The content of the polyfunctional epoxy resin represented by formula (7) in component (A) may be 80% by mass or less, 70% by mass or less, 60% by mass or less, or 55% by mass or less, based on the total mass of component (A).

[0038] (Hardening agent) The adhesive composition of this embodiment contains (B1) an onium compound (hereinafter also referred to as (B1) component) as component (B).

[0039] (B1) As component, onium salts such as sulfonium salts, pyridinium salts, phosphonium salts, ammonium salts, diazonium salts, iodonium salts, and anilinium salts can be used. The anion of the onium salt is BF4 - , BR4 -(R represents a phenyl group substituted with two or more fluorine atoms or two or more trifluoromethyl groups.) PF6 - SbF6 - AsF6 - These are some examples.

[0040] (B1) Component can be used alone or in combination of two or more types.

[0041] From the viewpoint of low-temperature curing properties, component (B1) may be a pyridinium salt or a sulfonium salt.

[0042] As the pyridinium salt, a pyridinium salt (hereinafter also referred to as "pyridinium salt A") can be used that has a benzyl group at position 1 and an electron-withdrawing group at position 2, wherein the benzyl group is an electron-donating group. In other words, pyridinium salt A has a pyridine ring and a benzene ring, with an electron-withdrawing group located at the ortho position relative to the nitrogen atom of the pyridine ring, and the benzene ring is an electron-donating group.

[0043] Pyridinium salt A may be a compound composed of a pyridinium cation and an anion. In this specification, position 1 of the pyridinium salt or pyridinium cation refers to the position of the nitrogen atom in the pyridine ring of the pyridinium salt or pyridinium cation.

[0044] Pyridinium salt A may be, for example, a compound represented by the following general formula (4). [ka] [In formula (4), R 31 R represents an electron-withdrawing group. 32 represents an electron-donating base, X - This represents an anion.

[0045] Examples of electron-withdrawing groups that pyridinium salt A may have at position 2 include cyano groups, halogeno groups, nitro groups, carbonyl groups, carboxyl groups, and sulfo groups. Examples of halogeno groups include fluoro groups, chloro groups, bromo groups, and iodo groups. From the viewpoint of increasing the activity of the curing agent and enabling the adhesive composition to cure in a shorter time, the electron-withdrawing group may be a cyano group or a halogeno group, or a cyano group or a chloro group. Pyridinium salt A may contain electron-withdrawing groups other than the potential-withdrawing group located at position 2. The number of electron-withdrawing groups in pyridinium salt A may be 3 or less, 2 or less, or 1.

[0046] The electron-donating group of the benzyl group positioned at position 1 of pyridinium salt A may include alkyl groups, alkoxy groups, hydroxyl groups, amino groups, alkylamino groups, etc. Examples of alkyl groups include methyl groups, ethyl groups, n-propyl groups, isopropyl groups, etc. Examples of alkoxy groups include methoxy groups, ethoxy groups, etc. The electron-withdrawing group may be an alkyl group or an alkoxy group, or a methyl group or a methoxy group, from the viewpoint of increasing the activity of the curing agent and allowing the adhesive composition to cure in a shorter time. The benzene ring may contain multiple electron-donating groups, and the number of electron-donating groups of the benzyl group positioned at position 1 of pyridinium salt A may be 1 or more, 2 or more, or 3 or more. The benzyl group positioned at position 1 of pyridinium salt A may have at least one electron-donating group at position 4 (position 4 when the bond position of the benzyl group to the pyridine ring is considered position 1; para position relative to the bond position of the benzyl group to the pyridine ring).

[0047] When the benzyl group positioned at position 1 of pyridinium salt A has 3 electron-donating groups, all three electron-donating groups may be alkyl groups or all may be methyl groups. Pyridinium salt A may have alkyl groups as electron-donating groups at positions 2, 4, and 6 of the benzyl group, with the bond position of the benzyl group to the pyridine ring being considered as position 1. By including a pyridinium salt in the curing agent, where the benzyl group positioned at position 1 of pyridinium salt A has 3 electron-donating groups, and all electron-donating groups are alkyl groups (or methyl groups), adhesive films using such a curing agent have excellent physical properties (e.g., elastic modulus). Therefore, adhesive films using such a curing agent can achieve both excellent adhesion to circuit members and excellent release properties of the substrate from the adhesive film. Furthermore, adhesive films using such a curing agent have excellent storage stability, and even when the adhesive film is stored for a certain period (e.g., 15 hours at 40°C), it is easy to maintain excellent adhesion to circuit members and excellent release properties of the substrate from the adhesive film. The reason for this is thought to be that the benzyl group positioned at position 1 of pyridinium salt A has three electron-donating groups, resulting in a well-balanced structure that maintains low-temperature curability while preventing deterioration during storage for a certain period (for example, 15 hours at 40°C) (excellent storage stability).

[0048] Examples of pyridinium cations in pyridinium salt A include 2-cyano-1-(4-methoxybenzyl)pyridinium cation, 2-chloro-1-(4-methoxybenzyl)pyridinium cation, 2-bromo-1-(4-methoxybenzyl)pyridinium cation, 2-cyano-1-(4-methylbenzyl)pyridinium cation, 2-chloro-1-(4-methylbenzyl)pyridinium cation, 2-bromo-1-(4-methylbenzyl)pyridinium cation, 2-cyano-1-(2,4,6-trimethylbenzyl)pyridinium cation, 2-chloro-1-(2,4,6-trimethylbenzyl)pyridinium cation, and 2-bromo-1-(2,4,6-trimethylbenzyl)pyridinium cation. The pyridinium cation of pyridinium salt A may be at least one selected from the group consisting of 2-cyano-1-(4-methoxybenzyl)pyridinium cation, 2-chloro-1-(4-methoxybenzyl)pyridinium cation, 2-cyano-1-(2,4,6-trimethylbenzyl)pyridinium cation, and 2-chloro-1-(2,4,6-trimethylbenzyl)pyridinium cation, from the viewpoint of enabling the adhesive composition to cure in a shorter time.

[0049] The anion of pyridinium salt A is SbF6 - PF6 - , PF X (CF3) 6-X - (where X is an integer from 1 to 5), BF4 - , B(C6F5)4 - , RSO3 - (However, R is an alkyl group having 1 to 3 carbon atoms, a substituted or unsubstituted aryl group), C(SO2CF3)3 - , B(C6H3(CF3)2)4 - (However, the CF3 group is substituted at the 3,5 position of the phenyl group. Examples include the tetrakis(3,5-bis(trifluoromethyl)phenyl)borate anion. The anion of pyridinium salt A is B(C6F5)4, which is chosen from the viewpoint of achieving better connection resistance. - , or B(C6H3(CF3)2)4 -(However, the CF3 group may be substituted at the 3,5 positions of the phenyl group.) That is, another embodiment of the present disclosure is a pyridinium salt comprising a pyridinium cation and an anion, wherein the pyridinium cation has a benzyl group at position 1 and an electron-withdrawing group at position 2, the benzyl group has an electron-donating group, and the anion is BB(C6F5)4 - , or B(C6H3(CF3)2)4 - It is a pyridinium salt (where the CF3 group is substituted at the 3,5 positions of the phenyl group). Also, the anion of pyridinium salt A is B(C6H3(CF3)2)4 - (However, if the CF3 group is substituted at the 3,5 position of the phenyl group, the anion of pyridinium salt A is B(C6H3(CF3)2)4 - Compared to cases other than those where the CF3 group is substituted at the 3rd and 5th positions of the phenyl group, it becomes easier to achieve superior connection resistance after HAST testing.

[0050] Pyridinium salt A may be a compound combining the above-mentioned pyridinium cation and the above-mentioned anion. From the viewpoint of enabling the adhesive composition to cure in a shorter time, pyridinium salt A may be 2-cyano-1-(4-methoxybenzyl)pyridinium·tetrakis(pentafluorophenyl)borate, 2-chloro-1-(4-methoxybenzyl)pyridinium·tetrakis(pentafluorophenyl)borate, 2-cyano-1-(2,4,6-trimethylbenzyl)pyridinium·tetrakis(pentafluorophenyl)borate, or 2-cyano-1-(4-meth It may be at least one selected from the group consisting of xybenzyl)pyridinium tetrakis(3,5-bis(trifluoromethyl)phenyl)borate, 2-chloro-1-(4-methoxybenzyl)pyridinium tetrakis(3,5-bis(trifluoromethyl)phenyl)borate, 2-cyano-1-(2,4,6-trimethylbenzyl)pyridinium tetrakis(3,5-bis(trifluoromethyl)phenyl)borate, and 2-chloro-1-(2,4,6-trimethylbenzyl)pyridinium tetrakis(3,5-bis(trifluoromethyl)phenyl)borate.

[0051] The adhesive composition of this embodiment comprises a pyridinium cation and an anion as component (B), wherein the pyridinium cation has a benzyl group at position 1 and an electron-withdrawing group at position 2, the benzyl group has an electron-donating group, and the anion is B(C6F5)4 - , or B(C6H3(CF3)2)4 -(However, the CF3 group is substituted at the 3- and 5-positions of the phenyl group), and contains a pyridinium salt (hereinafter, also referred to as "pyridinium salt A1"). Such a pyridinium salt A1 can cure the adhesive composition at a low temperature (115 °C) and can achieve excellent connection resistance. That is, another embodiment of the present disclosure is a pyridinium salt containing a pyridinium cation and an anion, wherein the pyridinium cation has a benzyl group at the 1-position and an electron-withdrawing group at the 2-position, the benzyl group has an electron-donating group, and the anion is B(C6F5)4 - or B(C6H3(CF3)2)4 - (However, the CF3 group is substituted at the 3- and 5-positions of the phenyl group), and is a pyridinium salt.

[0052] Also, another embodiment of the present disclosure is a curing agent containing pyridinium salt A1. The content of pyridinium salt A1 in the curing agent may be 80% by mass or more, 90% by mass or more, or 95% by mass or more based on the total mass of the curing agent, or may be 100% by mass (a mode in which the curing agent consists essentially of pyridinium salt A1).

[0053] The curing agent may contain a pyridinium salt other than pyridinium salt A1 (hereinafter, this pyridinium salt is also referred to as "pyridinium salt B") and an onium compound other than the pyridinium salt (for example, a sulfonium salt described later).

[0054] Pyridinium salt B is, for example, a pyridinium cation having a benzyl group at the 1-position and an electron-withdrawing group at the 2-position, and the benzyl group has an electron-donating group, and SbF6 - , PF6 - , PF X (CF3) 6-X - (However, X is an integer from 1 to 5), BF4 - , RSO3 - (However, R is an alkyl group having 1 to 3 carbon atoms, a substituted or unsubstituted aryl group), C(SO2CF3)3 - , N(SO2CF3)2 - , and O(SO2CF3) -It may also be a pyridinium salt containing at least one anion selected from the group consisting of

[0055] The pyridinium salt B may be, for example, a pyridinium salt having a borate ion having a 3,5-bis(trifluoromethyl)phenyl structure as an anion (excluding the tetrakis(3,5-bis(trifluoromethyl)phenyl)borate anion) (hereinafter, also referred to as "pyridinium salt B1"). By including the pyridinium salt B1, excellent connection resistance can be achieved even after the HAST test. The anion of the pyridinium salt B1 may have, for example, a structure represented by the following general formula (6).

[0056] [Chemical formula] [In formula (6), R 63 , R 64 , and R 65 each independently represent a monovalent organic group, and a, b, and c each independently represent an integer of 0 to 3. However, the tetrakis(3,5-bis(trifluoromethyl)phenyl)borate anion is excluded.]

[0057] R 63 , R 64 , and R 65 may each independently be, for example, a methyl group, an ethyl group, a fluoromethyl group, a difluoromethyl group, a trifluoromethyl group, a pentafluoromethyl group, and a perfluoroalkyl group. From the viewpoint of more easily realizing excellent connection resistance even after the HAST test, R 63 , R 64 , and R 65 may all be trifluoromethyl groups.

[0058] a, b, and c may each independently be 1 or more, 2 or more, or may be 2 or less. From the viewpoint of stabilizing the structure of the pyridinium salt A, a, b, and c may all be 2. When a, b, and c are 1, R 63 , R 64 , and R65 The benzyl group may be located at position 4 (position 4 when the bond position of the benzyl group to boron is considered position 1; para position relative to the bond position of the benzyl group to boron), and the trifluoromethyl group may be located at position 4 of the benzyl group. When a, b, and c are 2, R 63 , R 64 , and R 65 These may be located at positions 3 and 5 (positions 3 and 5 when the bond position of the benzyl group to boron is considered position 1; meta position relative to the bond position of the benzyl group to boron).

[0059] When the curing agent contains pyridinium salt A1 and pyridinium salt B, the ratio of the content of pyridinium salt A1 to the content of pyridinium salt B in the curing agent (content of pyridinium salt A1 / content of pyridinium salt B) may be 0.1 or more, 0.2 or more, or 0.5 or more, and may be 10 or less, 5 or less, or 2 or less.

[0060] A curing agent containing pyridinium salt A1 can be obtained, for example, by a manufacturing method comprising the steps of: reacting at least one of a pyridine compound having an electron-withdrawing group at the 2-position, a benzyl chloride compound having an electron-donating group, or a benzyl bromide compound having an electron-donating group with an alkali metal iodide salt (e.g., sodium iodide) in a solvent (e.g., acetonitrile) to obtain pyridinium iodide having a pyridine ring and a benzene ring; and reacting the obtained pyridinium iodide and an anionic salt in a solvent (e.g., dichloromethane) to obtain pyridinium salt A1.

[0061] The pyridine compound having an electron-withdrawing group at the 2-position may be any pyridine compound having the above-mentioned electron-withdrawing group at the 2-position, such as 2-cyanopyridine and 2-chloropyridine.

[0062] The benzyl chloride compound having an electron-donating group may be any of the above-mentioned benzyl chloride compounds having an electron-donating group, for example, 4-methoxybenzyl chloride and 2,4,6-trimethylbenzyl chloride. The benzyl bromide compound having an electron-donating group may be any of the above-mentioned benzyl bromide compounds having an electron-donating group, for example, 4-methoxybenzyl bromide and 2,4,6-trimethylbenzyl bromide.

[0063] The anionic salt can be any compound that can introduce the anion present in pyridinium salt A1, for example, the anion (B(C6F5)4 of pyridinium salt A1 mentioned above. - , or B(C6H3(CF3)2)4 - (However, the CF3 group is substituted at the 3,5 positions of the phenyl group.)) These may be lithium salts, sodium salts, potassium salts, or cesium salts.

[0064] In the process of obtaining pyridinium iodide, the reaction may be carried out, for example, at room temperature (20-30°C). The reaction time may be, for example, 10-50 hours or 20-30 hours. After the reaction is complete, the solvent used may be removed from the obtained pyridinium iodide by washing it with acetone, distilled water, etc., and then vacuum drying.

[0065] In the process of obtaining pyridinium iodide, the yield of pyridinium iodide may be 40% or more, 55% or more, 70% or more, or 80% or more. The yield of pyridinium iodide shall be the ratio of the amount actually obtained to the maximum amount of pyridinium iodide that can be obtained from the raw materials used in the synthesis of pyridinium iodide.

[0066] In the process of obtaining pyridinium salt A1, the reaction may be carried out, for example, at room temperature (20-30°C). The reaction time may be, for example, 1-15 hours or 1-5 hours. After the reaction is complete, the solvent used may be removed from the obtained pyridinium salt A1 by washing it with acetone, distilled water, etc., and then vacuum drying.

[0067] In the process of obtaining pyridinium salt A1, the yield of pyridinium salt A1 may be 70% or more, 80% or more, or 85% or more. The yield of pyridinium salt A1 is defined as the ratio of the amount actually obtained to the maximum amount of pyridinium salt A1 that can be obtained from the pyridinium iodide used in the synthesis of pyridinium salt A1.

[0068] The fact that pyridinium salt A1 was obtained means that the obtained compound can be analyzed using nuclear magnetic resonance spectroscopy ( 1 This can be confirmed by measurement using 1H-NMR. Specifically, it can be confirmed by the method described in the examples below.

[0069] The curing agent may include, for example, a sulfonium salt represented by the following general formula (5). [ka] [In formula (5), R 41 R represents a phenyl group, a 1-naphthyl group, a 2-naphthyl group, or a phenyl group having substituents at the o, m, or p position. 42 and R 43 represents an electron-donating base, Y - This represents an anion.

[0070] Examples of substituents on a phenyl group include methyl, cyano, halogeno, nitro, acetyl, carbonyl, carboxyl, and sulfo groups. Examples of halogeno groups include fluoro, chloro, bromo, and iodo groups.

[0071] Examples of electron-donating groups include amino groups, hydroxyl groups, and methyl groups.

[0072] Y - For example, SbF6 - PF6 - , PF X (CF3) 6-X - (where X is an integer from 1 to 5), BF4 - , B(C6F5)4 - , RSO3 -(However, R is an alkyl group having 1 to 3 carbon atoms, a substituted or unsubstituted aryl group), C(SO2CF3)3 - , B(C6H3(CF3)2)4 - (However, the CF3 group is substituted at the 3,5 positions of the phenyl group.)

[0073] A commercially available sulfonium salt such as 1-naphthylmethylmethyl-p-hydroxyphenylsulfonium hexafluoroantimonate (manufactured by Sanshin Chemical Industry Co., Ltd., trade name "San-Aid SI-60") can be used.

[0074] The content of component (B) in the adhesive composition may be 1% by mass or more, 2% by mass or more, 3% by mass or more, 4% by mass or more, or 5% by mass or more, based on the total mass of the adhesive composition, from the viewpoint of sufficiently promoting the curing reaction. The content of component (B) in the adhesive composition may be 20% by mass or less, 15% by mass or less, 10% by mass or less, 8% by mass or less, or 6% by mass or less, based on the total mass of the adhesive composition, from the viewpoint of improving the physical properties of the cured product. From these viewpoints, the content of component (B) in the adhesive composition may be 1 to 20% by mass, based on the total mass of the adhesive composition. The content of pyridinium salt A1 in the adhesive composition may be within the above content range.

[0075] The content of component (B) in the adhesive composition may be 1% by mass or more, 3% by mass or more, 5% by mass or more, or 7% by mass or more, based on the total mass of the adhesive composition excluding conductive particles, from the viewpoint of sufficiently promoting the curing reaction. The content of component (B) in the adhesive composition may be 30% by mass or less, 25% by mass or less, 20% by mass or less, 15% by mass or less, or 10% by mass or less, based on the total mass of the adhesive composition excluding conductive particles, from the viewpoint of improving the physical properties of the cured product. From these viewpoints, the content of component (B) in the adhesive composition may be 1 to 30% by mass, based on the total mass of the adhesive composition excluding conductive particles. The content of pyridinium salt A1 in the adhesive composition may be within the above content range.

[0076] From the viewpoint of sufficiently promoting the curing reaction, the content of component (B) in the adhesive composition may be 1% by mass or more, 3% by mass or more, 5% by mass or more, or 7% by mass or more, based on the total mass of the adhesive composition excluding conductive particles and fillers. From the viewpoint of improving the physical properties of the cured product, the content of component (B) in the adhesive composition may be 30% by mass or less, 25% by mass or less, 20% by mass or less, 15% by mass or less, or 10% by mass or less, based on the total mass of the adhesive composition excluding conductive particles and fillers. From these viewpoints, the content of component (B) in the adhesive composition may be 1 to 30% by mass, based on the total mass of the adhesive composition excluding conductive particles and fillers. The content of pyridinium salt A1 in the adhesive composition may be within the above content range.

[0077] The content of component (B) in the adhesive composition may be 1 part by mass or more, 5 parts by mass or more, 8 parts by mass or more, 10 parts by mass or more, or 12 parts by mass or more, based on 100 parts by mass of component (A), from the viewpoint of sufficiently promoting the curing reaction. The content of component (B) in the adhesive composition may be 40 parts by mass or less, 30 parts by mass or less, 20 parts by mass or less, 18 parts by mass or less, or 16 parts by mass or less, based on 100 parts by mass of component (A), from the viewpoint of improving the physical properties of the cured product. From these viewpoints, the content of component (B) in the adhesive composition may be 1 to 40 parts by mass, based on 100 parts by mass of component (A). The content of pyridinium salt A1 in the adhesive composition may be within the above content range.

[0078] (Film-forming components) The adhesive composition of this embodiment may contain a thermoplastic resin (component (C)). The inclusion of a thermoplastic resin makes the adhesive composition easier to form into a film. Examples of thermoplastic resins include phenoxy resin, epoxy resin, polyester resin, polyamide resin, polyurethane resin, polyester urethane resin, and acrylic rubber. These may be used individually or in combination of two or more. If the epoxy equivalent of the epoxy resin is 400 g / eq or more, it shall be treated as a thermoplastic resin.

[0079] The weight-average molecular weight (Mw) of the thermoplastic resin may be, for example, 5000 or more, 10000 or more, 20000 or more, or 40000 or more, and may be 200000 or less, 100000 or less, 80000 or less, or 60000 or less. The weight-average molecular weight of the thermoplastic resin shall be measured by gel permeation chromatography (GPC) and converted using a calibration curve with standard polystyrene.

[0080] The thermoplastic resin content may be 5% by mass or more, 10% by mass or more, or 15% by mass or more, based on the total mass of the adhesive composition. The thermoplastic resin content may be 40% by mass or less, 30% by mass or less, 20% by mass or less, or 10% by mass or less, based on the total mass of the adhesive composition.

[0081] The content of thermoplastic resin may be 10 parts by mass or more, 30 parts by mass or more, 50 parts by mass or more, or 60 parts by mass or more, based on 100 parts by mass of component (A). The content of thermoplastic resin may be 100 parts by mass or less, 80 parts by mass or less, 60 parts by mass or less, 40 parts by mass or less, or 20 parts by mass or less, based on 100 parts by mass of component (A).

[0082] The adhesive composition may contain conductive particles. The conductive particles are not particularly limited as long as they are conductive particles, and examples include metal particles composed of metals such as gold, silver, palladium, nickel, copper, and solder; conductive carbon particles composed of conductive carbon; and coated conductive particles comprising a core containing non-conductive glass, ceramic, or plastic (such as polystyrene), and a coating layer containing the above-mentioned metal or conductive carbon that covers the core. The conductive particles are easily deformed by heating and / or pressurizing, and coated conductive particles are preferable from the viewpoint that they can increase the contact area between the electrodes and the conductive particles when electrically connecting electrodes, thereby further improving conductivity between the electrodes.

[0083] The average particle diameter of conductive particles may be 1 μm or more, 2 μm or more, or 2.5 μm or more, from the viewpoint of excellent dispersibility and conductivity. The average particle diameter of conductive particles may be 20 μm or less, 15 μm or less, 10 μm or less, 8 μm or less, 6 μm or less, 5.5 μm or less, or 5 μm or less, from the viewpoint of ensuring insulation between adjacent electrodes. From these viewpoints, the average particle diameter of conductive particles may be 1 to 20 μm, 1 to 15 μm, 1 to 10 μm, 1 to 8 μm, or 1 to 6 μm.

[0084] The average particle diameter of conductive particles is determined by observing 300 conductive particles contained in the adhesive composition using a scanning electron microscope (SEM), measuring the particle diameter of each conductive particle, and taking the average of the particle diameters of the 300 conductive particles. If the conductive particles are not spherical, the particle diameter of the conductive particle is defined as the diameter of the circle circumscribing the conductive particle in the SEM observation image.

[0085] The particle density of conductive particles in the adhesive composition is set to 100 particles / mm² from the viewpoint of obtaining stable connection resistance. 2 More than 1000 pieces / mm 2 or more, or 3000 pieces / mm 2 The above is acceptable. The particle density of conductive particles in the adhesive composition should be 100,000 particles / mm² from the viewpoint of ensuring insulation between adjacent electrodes. 2 Below, 50000 pieces / mm 2 The following, or 30,000 pieces / mm 2 The following may apply: From these viewpoints, the particle density of conductive particles in the adhesive composition is 100 to 100,000 particles / mm². 2 , 1000~50000 pieces / mm 2 , or 3000-30000 pieces / mm 2 That's fine.

[0086] The content of conductive particles may be 10% by mass or more, 20% by mass or more, or 25% by mass or more, based on the total mass of the adhesive composition. The content of conductive particles may be 50% by mass or less, 40% by mass or less, or 35% by mass or less, based on the total mass of the adhesive composition.

[0087] The content of conductive particles may be 10 parts by mass or more, 30 parts by mass or more, 50 parts by mass or more, or 70 parts by mass or more, based on 100 parts by mass of component (A). The content of conductive particles may be 200 parts by mass or less, 150 parts by mass or less, 120 parts by mass or less, or 100 parts by mass or less, based on 100 parts by mass of component (A).

[0088] The adhesive composition may further contain a coupling agent. The adhesive properties of the adhesive composition can be further improved by the inclusion of a coupling agent. The coupling agent may be a silane coupling agent, such as vinyltrimethoxysilane, vinyltriethoxysilane, 3-glycidoxypropyltrimethoxysilane, 3-glycidoxypropylmethyldiethoxysilane, 3-(meth)acryloxypropylmethyldimethoxysilane, 3-(meth)acryloxypropyltrimethoxysilane, 3-(meth)acryloxypropylmethyldiethoxysilane, 3-(meth)acryloxypropyltriethoxysilane, N-2-(aminoethyl)-3-aminopropylmethyldimethoxysilane, N-phenyl-3-aminopropyltrimethoxysilane, 3-ureidopropyltriethoxysilane, 3-mercaptopropyltrimethoxysilane, 3-isocyanatetopropyltriethoxysilane, and condensates thereof. These may be used individually or in combination of two or more.

[0089] The coupling agent content may be 0.5% by mass or more, 1% by mass or more, or 2% by mass or more, based on the total mass of the adhesive composition. The coupling agent content may be 15% by mass or less, 10% by mass or less, or 5% by mass or less, based on the total mass of the adhesive composition.

[0090] The content of the coupling agent may be 1 part by mass or more, 3 parts by mass or more, or 5 parts by mass or more, based on 100 parts by mass of component (A). The content of the coupling agent may be 30 parts by mass or less, 20 parts by mass or less, 10 parts by mass or less, or 8 parts by mass or less, based on 100 parts by mass of component (A).

[0091] The adhesive composition may further contain a filler. The adhesive composition can further improve connection reliability by containing a filler. Examples of fillers include non-conductive fillers (e.g., non-conductive particles). The filler may be either an inorganic filler or an organic filler.

[0092] Examples of inorganic fillers include metal oxide particles such as silica particles, alumina particles, silica-alumina particles, titania particles, and zirconia particles; and metal nitride particles. These may be used individually or in combination of two or more types.

[0093] Examples of organic fillers include silicone particles, methacrylate-butadiene-styrene particles, acrylic-silicone particles, polyamide particles, and polyimide particles. These may be used individually or in combination of two or more types.

[0094] The filler may be an inorganic filler, or silica particles, from the viewpoint of improving film moldability and the reliability of the connecting structure. The silica particles may be crystalline silica particles or amorphous silica particles, and these silica particles may be synthetic products. The silica may be synthesized by a dry method or a wet method. The silica particles may include at least one selected from the group consisting of fumed silica particles and sol-gel silica particles.

[0095] The silica particles may be surface-treated silica particles from the viewpoint of excellent dispersibility in adhesive components. Surface-treated silica particles are obtained by hydrophobizing the hydroxyl groups on the surface of the silica particles with a silane compound or a silane coupling agent. Surface-treated silica particles may be silica particles surface-treated with a silane compound such as an alkoxysilane compound, a disilazane compound, or a siloxane compound, or silica particles surface-treated with a silane coupling agent.

[0096] Examples of alkoxysilane compounds include methyltrimethoxysilane, dimethyldimethoxysilane, phenyltrimethoxysilane, dimethoxydiphenylsilane, tetraethoxysilane, methyltriethoxysilane, dimethyldiethoxysilane, phenyltriethoxysilane, n-propyltrimethoxysilane, n-propyltriethoxysilane, hexyltrimethoxysilane, hexyltriethoxysilane, octyltriethoxysilane, decyltrimethoxysilane, 1,6-bis(trimethoxysilyl)hexane, and 3,3,3-trifluoropropyltrimethoxysilane.

[0097] Examples of disilazane compounds include 1,1,1,3,3,3-hexamethyldisilazane, 1,3-diphenyltetramethyldisilazane, 1,3-bis(3,3,3,-trifluoropropyl)-1,1,3,3,-tetramethyldisilazane, and 1,3-divinyl-1,1,3,3-tetramethyldisilazane.

[0098] Siloxane compounds include tetradecamethylcycloheptasiloxane, decamethylcyclopentasiloxane, hexaphenylcyclosiloxane, octadecamethylcyclononasiloxane, hexadecamethylcyclooctasiloxane, dodecamethylcyclohexasiloxane, octaphenylcyclotetrasiloxane, hexamethylcyclotrisiloxane, heptaphenyldisiloxane, tetradecamethylhexasiloxane, dodecamethylpentasiloxane, hexame Til disiloxane, decamethyltetrasiloxane, hexamethoxydisiloxane, octamethyltrisiloxane, octamethylcyclotetrasiloxane, 1,3-vinyltetramethyldisiloxane, 2,4,6-trimethyl-2,4,6-trivinylcyclotrisiloxane, 1,3-dimethoxy-1,1,3,3-tetraphenyldisiloxane, 1,1,3,3-tetramethyl-1,3-diphenyldisiloxane, 1,3-dimethyl-1,3-diphenyl-1,3- Divinyldisiloxane, 2,4,6,8-tetramethyl-2,4,6,8-tetravinylcyclotetrasiloxane, 1,1,1,3,5,5,5-heptamethyl-3-(3-glycidoyloxypropyl)trisiloxane, 1,3,5-tris(3,3,3-trifluoropropyl)-1,3,5-trimethylcyclotrisiloxane, 1,1,1,3,5,5,5-heptamethyl-3-[(trimethylsilyl)oxy]trisiloxane, 1,3,-bis[2-(7 Examples include -oxabicyclo[4.1.0]heptan-3-yl)ethyl]-1,1,3,3,-tetramethyldisiloxane, 1,1,1,5,5,5-hexamethyl-3-[(trimethylsilyl)oxy]-3-vinyltrisiloxane, 3-[[dimethyl(vinyl)silyl]oxy]-1,1,5,5,-tetramethyl-3-phenyl-1,5-vinyltrisiloxane, octavinyloctasilsesquioxane, octaphenyloctasilsesquioxane, etc.

[0099] Examples of silane coupling agents include vinyltrimethoxysilane, vinyltriethoxysilane, 2-(3,4-epoxycyclohexyl)ethyltrimethoxysilane, 3-glycidoxypropylmethyldimethoxysilane, 3-glycidoxypropyltrimethoxysilane, 3-glycidoxypropylmethyldiethoxysilane, 3-glycidoxypropyltriethoxysilane, p-styryltrimethoxysilane, 3-methacryloxypropylmethyldimethoxysilane, 3-methacryloxypropyltrimethoxysilane, 3-methacryloxypropylmethyldiethoxysilane, 3-methacryloxypropyltriethoxysilane, 3-acryloxypropyltrimethoxysilane, N-2-(Ammyl Examples include (noethyl)-3-aminopropylmethyldimethoxysilane, N-2-(aminoethyl)-3-aminopropyltrimethoxysilane, 3-aminopropyltrimethoxysilane, 3-aminopropyltriethoxysilane, 3-triethoxysilyl-N-(1,3-dimethylbutylidene)propylamine, N-phenyl-3-aminopropyltrimethoxysilane, tris-(trimethoxysilylpropyl)isocyanurate, 3-ureidopropyltrialkoxysilane, 3-mercaptopropylmethyldimethoxysilane, 3-mercaptopropyltrimethoxysilane, 3-isocyanatetopropyltriethoxysilane, and 3-trimethoxysilylpropyl succinic anhydride.

[0100] Silica particles surface-treated with a silane compound or silane coupling agent may be further surface-treated with silane compounds such as 3-methacryloxypropyltrimethoxysilane, vinyltrimethoxysilane, or trimethoxyphenylsilane to further hydrophobize the hydroxyl group residues on the surface of the silica particles.

[0101] Surface-treated silica particles may contain at least one selected from the group consisting of reaction products of silica and trimethoxyoctylsilane (hydrolysis products), reaction products of silica and dimethylsiloxane, reaction products of silicon dioxide or silica and dichloro(dimethyl)silane, reaction products of silica and bis(trimethylsilyl)amine (hydrolysis products), and reaction products of silica and hexamethyldisilazane, from the viewpoint of easily controlling fluidity when the adhesive film is pressed together when the adhesive composition is used as an adhesive film for circuit connection, and from the viewpoint of improving the mechanical properties and water resistance of the connected structure after pressing. They may also contain at least one selected from the group consisting of reaction products of silica and trimethoxyoctylsilane and reaction products of silica and bis(trimethylsilyl)amine.

[0102] The filler content may be 1% by mass or more, 3% by mass or more, or 5% by mass or more, based on the total mass of the adhesive composition. The filler content may be 50% by mass or less, 40% by mass or less, or 35% by mass or less, based on the total mass of the adhesive composition.

[0103] The content of the filler may be 1 part by mass or more, 5 parts by mass or more, or 10 parts by mass or more, based on 100 parts by mass of component (A). The content of the filler may be 200 parts by mass or less, 150 parts by mass or less, or 100 parts by mass or less, based on 100 parts by mass of component (A).

[0104] The adhesive composition may further contain other components besides those listed above. These other components may include stabilizers, colorants, antioxidants, etc. The adhesive composition may further contain a radical polymerizable compound and a radical polymerization initiator.

[0105] Examples of radical polymerizable compounds include acrylic compounds. Examples of acrylic compounds include (meth)acrylic acid compounds, (meth)acrylate compounds, and their imide compounds. These may be used in monomer or oligomer form, or in combination. Radical polymerizable compounds may be used individually or in combination of two or more.

[0106] Examples of acrylic compounds include alkyl (meth)acrylate compounds such as methyl acrylate, ethyl acrylate, isopropyl acrylate, and isobutyl acrylate; polyol poly(meth)acrylate compounds such as ethylene glycol diacrylate, diethylene glycol diacrylate, trimethylolpropane triacrylate, and tetramethylolmethane tetraacrylate; aryloxy-hydroxyalkyl (meth)acrylate compounds such as 2-hydroxy-1,3-diacryloxypropane, 2,2-bis[4-(acryloxymethoxy)phenyl]propane, and 2,2-bis[4-(acryloxypolyethoxy)phenyl]propane; dicyclopentenyl acrylate, tricyclodecanyl acrylate, and tris(acryloyloxyethyl) isocyanurate.

[0107] Radical polymerization initiators may generate free radicals upon exposure to light or heat. Examples of radical polymerization initiators include organic peroxides and azo compounds. Examples of organic peroxides include peroxyesters, dialkyl peroxides, diacyl peroxides, peroxydicarbonates, peroxyketals, hydroperoxides, and silyl peroxides. Radical polymerization initiators may be used individually or in combination of two or more.

[0108] Examples of peroxyesters include cumyl peroxyneodecanoate, 1,1,3,3-tetramethylbutyl peroxyneodecanoate, 1-cyclohexyl-1-methylethyl peroxyneodecanoate, t-hexyl peroxyneodecanoate, t-butyl peroxypivalate, 1,1,3,3-tetramethylbutyl peroxy-2-ethylhexanonate, 2,5-dimethyl-2,5-di(2-ethylhexanoylperoxy)hexane, 1-cyclohexyl-1-methylethyl peroxy-2-ethylhexanonate, L-hexyl peroxy-2-ethylhexanonate, L- Examples include butyl peroxy-2-ethylhexanonate, t-butyl peroxyisobutyrate, 1,1-bis(t-butylperoxy)cyclohexane, t-hexyl peroxyisopropyl monocarbonate, t-butyl peroxy-3,5,5-trimethylhexanonate, t-butyl peroxylaurate, 2,5-dimethyl-2,5-di(m-toluylperoxy)hexane, t-butyl peroxyisopropyl monocarbonate, t-butyl peroxy-2-ethylhexyl monocarbonate, t-hexyl peroxybenzoate, and t-butyl peroxyacetate.

[0109] Examples of dialkyl peroxides include α,α'-bis(t-butylperoxy)diisopropylbenzene, dicumyl peroxide, 2,5-dimethyl-2,5-di(t-butylperoxy)hexane, and t-butylcumyl peroxide. Examples of hydroperoxides include diisopropylbenzene hydroperoxide and cumene hydroperoxide.

[0110] Examples of diacyl peroxides include isobutyl peroxide, 2,4-dichlorobenzoyl peroxide, 3,5,5-trimethylhexanoyl peroxide, octanoyl peroxide, lauroyl peroxide, stearoyl peroxide, succinic peroxide, benzoyl peroxytoluene, and benzoyl peroxide.

[0111] Examples of peroxydicarbonates include di-n-propyl peroxydicarbonate, diisopropyl peroxydicarbonate, bis(4-t-butylcyclohexyl)peroxydicarbonate, di-2-ethoxymethoxyperoxydicarbonate, di(2-ethylhexylperoxy)dicarbonate, dimethoxybutyl peroxydicarbonate, and di(3-methyl-3-methoxybutylperoxy)dicarbonate.

[0112] Specific examples of peroxyketals include 1,1-bis(t-hexylperoxy)-3,3,5-trimethylcyclohexane, 1,1-bis(t-hexylperoxy)cyclohexane, 1,1-bis(t-butylperoxy)-3,3,5-trimethylcyclohexane, 1,1-(t-butylperoxy)cyclododecane, and 2,2-bis(t-butylperoxy)decane.

[0113] Specific examples of silyl peroxides include t-butyltrimethylsilyl peroxide, bis(t-butyl)dimethylsilyl peroxide, t-butyltrivinylsilyl peroxide, bis(t-butyl)divinylsilyl peroxide, tris(t-butyl)vinylsilyl peroxide, t-butyltrialylsilyl peroxide, bis(t-butyl)diallylsilyl peroxide, and tris(t-butyl)allylsilyl peroxide.

[0114] <Adhesive film for circuit connections> The adhesive film for circuit connection of this embodiment has a region formed by the adhesive composition of this embodiment described above. The region may be in the form of a film or a layer. That is, another embodiment of the present disclosure is an adhesive film for circuit connection containing component (A) and component (B). The adhesive film for circuit connection may contain conductive particles.

[0115] When the adhesive composition of this embodiment contains conductive particles, the particle density of the conductive particles in the adhesive film for circuit connection is 100 particles / mm² from the viewpoint of obtaining stable connection resistance. 2 More than 1000 pieces / mm 2 or more, or 3000 pieces / mm 2 The above is acceptable. The particle density of conductive particles in the adhesive film for circuit connections should be 100,000 particles / mm² from the viewpoint of ensuring insulation between adjacent electrodes. 2 Below, 50000 pieces / mm 2 The following, or 30,000 pieces / mm 2 The following may apply. From these perspectives, the particle density of conductive particles in the adhesive film for circuit connections is 100 to 100,000 particles / mm². 2 , 1000~50000 pieces / mm 2 , or 3000-30000 pieces / mm 2 That's fine.

[0116] The content of conductive particles may be 10% by mass or more, 20% by mass or more, or 25% by mass or more, based on the total mass of the adhesive film for circuit connection. The content of conductive particles may be 50% by mass or less, 40% by mass or less, or 35% by mass or less, based on the total mass of the adhesive film for circuit connection.

[0117] The content of conductive particles may be 10 parts by mass or more, 30 parts by mass or more, 50 parts by mass or more, or 70 parts by mass or more, based on 100 parts by mass of component (A). The content of conductive particles may be 200 parts by mass or less, 150 parts by mass or less, 120 parts by mass or less, or 100 parts by mass or less, based on 100 parts by mass of component (A).

[0118] The content of component (A) in the circuit connection adhesive film may be 10% by mass or more, 20% by mass or more, 25% by mass or more, or 30% by mass or more, based on the total mass of the circuit connection adhesive film, from the viewpoint of ensuring the curability of the circuit connection adhesive film. The content of component (A) in the circuit connection adhesive film may be 60% by mass or less, 50% by mass or less, 45% by mass or less, or 40% by mass or less, based on the total mass of the circuit connection adhesive film, from the viewpoint of ensuring the formability of the circuit connection adhesive film. From these viewpoints, the content of component (A) in the circuit connection adhesive film may be 10 to 60% by mass, based on the total mass of the circuit connection adhesive film.

[0119] The content of component (B) in the circuit connection adhesive film may be 1% by mass or more, 2% by mass or more, 3% by mass or more, 4% by mass or more, or 5% by mass or more, based on the total mass of the circuit connection adhesive film, from the viewpoint of sufficiently promoting the curing reaction. The content of component (B) in the circuit connection adhesive film may be 20% by mass or less, 15% by mass or less, 10% by mass or less, 8% by mass or less, or 6% by mass or less, based on the total mass of the circuit connection adhesive film, from the viewpoint of improving the physical properties of the cured product. From these viewpoints, the content of component (B) in the circuit connection adhesive film may be 1 to 20% by mass, based on the total mass of the circuit connection adhesive film.

[0120] The content of component (B) in the circuit connection adhesive film may be 1% by mass or more, 3% by mass or more, 5% by mass or more, or 7% by mass or more, based on the total mass of the circuit connection adhesive film excluding conductive particles, from the viewpoint of sufficiently promoting the curing reaction. The content of component (B) in the circuit connection adhesive film may be 30% by mass or less, 25% by mass or less, 20% by mass or less, 15% by mass or less, or 10% by mass or less, based on the total mass of the circuit connection adhesive film excluding conductive particles, from the viewpoint of improving the physical properties of the cured product. From these viewpoints, the content of component (B) in the circuit connection adhesive film may be 1 to 30% by mass, based on the total mass of the circuit connection adhesive film excluding conductive particles.

[0121] The content of component (B) in the circuit connection adhesive film may be 1% by mass or more, 3% by mass or more, 5% by mass or more, or 7% by mass or more, based on the total mass of the circuit connection adhesive film excluding conductive particles and fillers, from the viewpoint of sufficiently promoting the curing reaction. The content of component (B) in the circuit connection adhesive film may be 30% by mass or less, 25% by mass or less, 20% by mass or less, 15% by mass or less, or 10% by mass or less, based on the total mass of the circuit connection adhesive film excluding conductive particles and fillers, from the viewpoint of improving the physical properties of the cured product. From these viewpoints, the content of component (B) in the circuit connection adhesive film may be 1 to 30% by mass, based on the total mass of the circuit connection adhesive film excluding conductive particles and fillers.

[0122] The thermoplastic resin content in the circuit connection adhesive film may be 5% by mass or more, 10% by mass or more, or 15% by mass or more, based on the total mass of the circuit connection adhesive film. The thermoplastic resin content in the circuit connection adhesive film may be 40% by mass or less, 30% by mass or less, or 20% by mass or less, based on the total mass of the circuit connection adhesive film.

[0123] The coupling agent content in the circuit connection adhesive film may be 0.5% by mass or more, 1% by mass or more, or 1.5% by mass or more, based on the total mass of the circuit connection adhesive film. The coupling agent content in the circuit connection adhesive film may be 10% by mass or less, 5% by mass or less, or 3% by mass or less, based on the total mass of the circuit connection adhesive film.

[0124] The filler content in the adhesive film for circuit connections may be 1% by mass or more, 3% by mass or more, or 5% by mass or more, based on the total mass of the adhesive film for circuit connections. The filler content in the adhesive film for circuit connections may be 50% by mass or less, 40% by mass or less, or 35% by mass or less, based on the total mass of the adhesive film for circuit connections.

[0125] The content of each component in the adhesive film for circuit connections, based on 100 parts by mass of component (A), may be within the same range as the content of each component in the adhesive composition based on 100 parts by mass of component (A).

[0126] The adhesive film for circuit connections may be a single layer or may have a multilayer structure in which multiple layers are laminated. When the adhesive film for circuit connections has a multilayer structure, it may comprise, for example, a first adhesive layer containing component (A) and component (B), and a second adhesive layer other than the first adhesive layer. That is, the adhesive film for circuit connections may comprise a first adhesive layer and a second adhesive layer laminated on the first adhesive layer. At least one of the first adhesive layer and the second adhesive layer may contain component (A), component (B), and conductive particles. When the adhesive film for circuit connections has a multilayer structure, the content of each of the above components in each layer may be within the above content range based on the total mass of each layer.

[0127] The adhesive film for circuit connections may have multiple regions with different types and contents of components. The adhesive film for circuit connections may, for example, comprise a first region and a second region placed on the first region, and the first region may contain component (A) and component (B). That is, the adhesive film for circuit connections may have a first region which is formed from a first adhesive composition containing component (A) and component (B), and a second region which is formed from a second adhesive composition placed on the first region. When the adhesive film for circuit connections has multiple regions, the contents of each component in each region may be within the range of the above contents based on the total mass of each region.

[0128] The adhesive film for circuit connections may be provided on a substrate (e.g., a PET film). The adhesive film for circuit connections with a substrate can be manufactured, for example, by applying an adhesive composition containing conductive particles onto the substrate using a knife coater, roll coater, applicator, comma coater, die coater, or the like.

[0129] Figure 1 is a schematic cross-sectional view showing an adhesive film for circuit connection according to one embodiment. As shown in Figure 1, in one embodiment, the adhesive film 1 for circuit connection is composed of a single layer consisting of an adhesive component 2 and conductive particles 3 dispersed in the adhesive component 2. In one embodiment, the adhesive component 2 contains at least the above-described components (A) and (B). The adhesive film 1 for circuit connection may be in an uncured state or may be partially cured.

[0130] The thickness of the circuit connection adhesive film 1 may be, for example, 3 μm or more or 10 μm or more, and 30 μm or less or 20 μm or less.

[0131] In one embodiment, the adhesive film for circuit connection comprises a first region containing a first adhesive component and a second region adjacent to the first region containing a second adhesive component, wherein one or both of the first and second regions may be formed of the adhesive composition of this embodiment described above. The first region and the second region may each be layers.

[0132] In one embodiment, the adhesive film for circuit connection may have a multilayer structure having two or more layers. For example, as shown in Figure 2, the adhesive film for circuit connection 1 may have a two-layer structure comprising a layer containing conductive particles 3A (a first adhesive layer consisting of adhesive component 2A and conductive particles 3A dispersed in adhesive component 2A) 1A, and a layer not containing conductive particles (a second adhesive layer consisting of adhesive component 2B) 1B. In this case, the first adhesive layer 1A may be a layer made of an adhesive composition (first adhesive composition) containing at least the above-mentioned components (A) and (B) and conductive particles. The second adhesive layer 1B may be a layer made of an adhesive composition (second adhesive composition) containing at least the above-mentioned components (A) and (B). The types and contents of each component contained in the second adhesive layer 1B may be the same as or different from those of the first adhesive layer 1A. The first adhesive layer 1A and the second adhesive layer 1B of the adhesive film for circuit connection 1 may be in an uncured state or partially cured.

[0133] The thickness of the first adhesive layer 1A may be, for example, 1 μm or more or 3 μm or more, and 15 μm or less or 10 μm or less. The thickness of the second adhesive layer 1B may be, for example, 1 μm or more or 3 μm or more, and 20 μm or less or 15 μm or less. The thickness of the first adhesive layer 1A may be the same as or different from the thickness of the second adhesive layer 1B. The ratio of the thickness of the first adhesive layer 1A to the thickness of the second adhesive layer 1B (thickness of the first adhesive layer 1A / thickness of the second adhesive layer 1B) may be 0.1 or more or 0.3 or more, and 1.5 or less or 0.5 or less.

[0134] The above-mentioned adhesive film for circuit connection may be an anisotropic conductive adhesive film (anisotropic conductive film), or it may be a conductive adhesive film that does not have anisotropic conductivity.

[0135] <Connection Structure> Another embodiment of the present disclosure is a connecting structure comprising a first circuit member having a first electrode, a second circuit member having a second electrode, and a connecting portion disposed between the first circuit member and the second circuit member and electrically connecting the first electrode and the second electrode to each other, wherein the connecting portion includes a cured product of the above-mentioned adhesive film for circuit connection.

[0136] Figure 3 is a schematic cross-sectional view showing one embodiment of the connecting structure. As shown in Figure 3, the structure 10 comprises a first circuit member 4 and a second circuit member 5 facing each other, and a connecting portion 6 that connects the first circuit member 4 and the second circuit member 5 between them.

[0137] The first circuit member 4 comprises a first circuit board 41 and a first electrode 42 formed on the main surface 41a of the first circuit board 41. The second circuit member 5 comprises a second circuit board 51 and a second electrode 52 formed on the main surface 51a of the second circuit board 51.

[0138] The first circuit member 4 and the second circuit member 5 are not particularly limited as long as they are members on which electrodes requiring electrical connection are formed. Examples of members on which electrodes are formed (circuit members, etc.) include inorganic substrates such as semiconductors, glass, and ceramics; polyimide substrates represented by TCP, FPC, COF, etc.; substrates on which electrodes are formed on films such as polycarbonate, polyester, and polyethersulfone; and printed wiring boards. Multiple of these may be used in combination.

[0139] The connection portion 6 contains a cured product of the circuit connection adhesive film 1, an insulating substance 7 which is a cured product of the adhesive component 2, and conductive particles 3. The conductive particles 3 may be arranged not only between the opposing first electrode 42 and second electrode 52, but also between the main surface 41a of the first circuit board 41 and the main surface 51a of the second circuit board 51. In the structure 30, the first electrode 42 and the second electrode 52 are electrically connected via the conductive particles 3. That is, the conductive particles 3 are in contact with both the first electrode 42 and the second electrode 52.

[0140] In structure 10, as described above, the opposing first electrode 42 and second electrode 52 are electrically connected via the conductive particle 3. Therefore, the connection resistance between the first electrode 42 and the second electrode 52 is sufficiently reduced. Consequently, it is possible to facilitate the flow of current between the first electrode 42 and the second electrode 52, and the functions of the first circuit member 4 and the second circuit member 5 can be fully performed.

[0141] <Method for manufacturing a connecting structure> Another embodiment of the present disclosure is a method for manufacturing a connection structure, comprising the steps of interposing the above-mentioned circuit connection adhesive film between a first circuit member having a first electrode and a second circuit member having a second electrode, and then heat-pressing the first circuit member and the second circuit member together to electrically connect the first electrode and the second electrode.

[0142] Figure 4 is a schematic cross-sectional view showing one embodiment of a method for manufacturing a connection structure. As shown in Figure 4(a), first, a first circuit member 4 and a circuit connection adhesive film 1 are prepared. Next, the circuit connection adhesive film 1 is placed on the main surface 41a of the first circuit member 4. If the circuit connection adhesive film 1 is laminated on a substrate (not shown), the laminate is placed on the first circuit member 4 such that the side of the substrate with the circuit connection adhesive film 1 faces the first circuit member 4. If the circuit connection adhesive film 1 has a first adhesive layer 1A and a second adhesive layer 1B as shown in Figure 2, it is preferable to place the adhesive layer containing conductive particles (first adhesive layer 1A) in contact with the main surface 41a of the first circuit member 4, from the viewpoint of improving the number of conductive particles trapped between opposing electrodes.

[0143] Then, the circuit connection adhesive film 1 is pressed in the directions of arrows A and B in Figure 4(a) to temporarily connect the circuit connection adhesive film 1 to the first circuit member 4 (see Figure 4(b)). At this time, heating may be performed along with the pressurization.

[0144] Next, as shown in Figure 4(c), the second circuit member 5 is further placed on the circuit connection adhesive film 1 placed on the first circuit member 4, with the second electrode 52 facing the first circuit member 4 (i.e., the first electrode 42 and the second electrode 52 are positioned facing each other, with the circuit connection adhesive film 1 interposed between the first circuit member 4 and the second circuit member 5). If the circuit connection adhesive film 1 is laminated on a substrate (not shown), the substrate is peeled off before placing the second circuit member 5 on the circuit connection adhesive film 1.

[0145] Then, the circuit connection adhesive film 1 is heat-pressed in the directions of arrows A and B in Figure 4(c). This hardens the circuit connection adhesive film 1, and the main connection is made, electrically connecting the first electrode 42 and the second electrode 52 to each other. As a result, a structure 10 as shown in Figure 3 is obtained.

[0146] In the structure 10 obtained as described above, it is possible to bring the conductive particles 3 into contact with both the opposing first electrode 42 and the second electrode 52, and the connection resistance between the first electrode 42 and the second electrode 52 can be sufficiently reduced.

[0147] By heating and pressurizing the circuit connection adhesive film 1, the adhesive component 2 hardens into an insulating material 7 while the distance between the first electrode 42 and the second electrode 52 is sufficiently reduced, and the first circuit member 4 and the second circuit member 5 are firmly connected via the connection part 6. Furthermore, in the structure 10, a sufficiently high adhesive strength is maintained over a long period of time. Therefore, in the structure 10, changes in the distance between the first electrode 42 and the second electrode 52 over time are sufficiently suppressed, and the long-term reliability of the electrical characteristics between the first electrode 42 and the second electrode 52 is excellent. [Examples]

[0148] The present disclosure will be specifically described below with reference to examples. However, the present disclosure is not limited to the examples described below.

[0149] <Synthesis of pyridinium salt (hardener B1)> 100 mL of acetonitrile and a stirrer tip were placed in a 300 mL Erlenmeyer flask and set on a magnetic stirrer. 12.5 g (120 mmol, manufactured by Tokyo Chemical Industry Co., Ltd.), 16.8 g (100 mmol, manufactured by Tokyo Chemical Industry Co., Ltd.) of 2-cyanopyridine, 17.8 g (119 mmol, manufactured by Tokyo Chemical Industry Co., Ltd.) of 2,4,6-trimethylbenzyl chloride, and 17.8 g (119 mmol, manufactured by Tokyo Chemical Industry Co., Ltd.) of sodium iodide were added to the acetonitrile in the 300 mL Erlenmeyer flask and reacted at room temperature (25°C) for 24 hours to obtain crystals. The obtained crystals were filtered through a glass filter, and after washing the crystals on the glass filter with acetone and distilled water, they were vacuum-dried to obtain 29.1 g of 2-cyano-1-(2,4,6-trimethylbenzyl)pyridinium iodide (yield 80%).

[0150] 200 mL of dichloromethane and a stirrer tip were placed in a 500 mL Erlenmeyer flask and set on a magnetic stirrer. 3.6 g (10 mmol) of the obtained 2-cyano-1-(2,4,6-trimethylbenzyl)pyridinium iodide was added to the 500 mL Erlenmeyer flask and suspended in the dichloromethane in the flask. 72 g (10.2 mmol, manufactured by Nippon Shokubai Co., Ltd.) of an aqueous solution of sodium tetrakis(pentafluorophenyl)borate (10% solids) and 50 mL of distilled water were added to the 500 mL Erlenmeyer flask, and the salt exchange reaction was carried out by stirring at room temperature (25°C) for 3 hours. After stirring, the organic layer was washed with distilled water, concentrated, and vacuum-dried to obtain 8.0 g of the compound (yield 88%). The obtained compound was designated as curing agent B1.

[0151] The obtained compounds were measured using nuclear magnetic resonance spectroscopy (1H-NMR, JEOL Ltd., JNM-ECX400II), and the following spectral data was obtained. 1 Measurement by 1H-NMR confirmed that the obtained compound is 2-cyano-1-(2,4,6-trimethylbenzyl)pyridinium tetrakis(pentafluorophenyl)borate, which has the structure shown below. 1 H-NMR(400MHz,CD3OD),δ:2.26(s,6H),2.32(s,3H),6.10(s,2H),7.08(s,2H),8.25(td,1H,J=3.2,6.4Hz)8.43(d,1H,J=6.4Hz)8.77-8.82(m,2H)

[0152] [ka]

[0153] <Synthesis of pyridinium salt (hardener B3)> 100 mL of acetonitrile and a stirrer tip were placed in a 300 mL Erlenmeyer flask and set on a magnetic stirrer. 12.5 g (120 mmol, manufactured by Tokyo Chemical Industry Co., Ltd.), 16.8 g (100 mmol, manufactured by Tokyo Chemical Industry Co., Ltd.) of 2-cyanopyridine, 17.8 g (119 mmol, manufactured by Tokyo Chemical Industry Co., Ltd.) of 2,4,6-trimethylbenzyl chloride, and 17.8 g (119 mmol, manufactured by Tokyo Chemical Industry Co., Ltd.) of sodium iodide were added to the acetonitrile in the 300 mL Erlenmeyer flask and reacted at room temperature (25°C) for 24 hours to obtain crystals. The obtained crystals were filtered through a glass filter, and after washing the crystals on the glass filter with acetone and distilled water, they were vacuum-dried to obtain 29.1 g of 2-cyano-1-(2,4,6-trimethylbenzyl)pyridinium iodide (yield 80%). 200 mL of dichloromethane and a stirrer tip were placed in a 500 mL Erlenmeyer flask and set on a magnetic stirrer. 3.6 g (10 mmol) of the obtained 2-cyano-1-(2,4,6-trimethylbenzyl)pyridinium iodide was added to the 500 mL Erlenmeyer flask and suspended in the dichloromethane in the flask. 9.2 g (10.2 mmol, manufactured by Tokyo Chemical Industry Co., Ltd.) of tetrakis[3,5-bis(trifluoromethyl)phenyl]sodium borate hydrate and 100 mL of distilled water were added to the 500 mL Erlenmeyer flask, and the salt exchange reaction was carried out by stirring at room temperature (25°C) for 3 hours. After stirring, the organic layer was washed with distilled water, concentrated, and vacuum-dried to obtain 8.2 g of the compound (yield 75%). The obtained compound was designated as curing agent B3.

[0154] The obtained compound was subjected to nuclear magnetic resonance spectroscopy ( 1 When measured using 1H-NMR (JEOL Ltd., JNM-ECX400II), the following spectral data was obtained. 1 Measurement by 1H-NMR confirmed that the obtained compound is 2-cyano-1-(2,4,6-trimethylbenzyl)pyridinium·tetrakis[3,5-bis(trifluoromethyl)phenyl]borate, which has the structure shown below. 1H-NMR(400MHz,(CD3)2O),δ:2.34(s,9H),6.31(s,2H),7.14(s,2H),7.68(s,4 H),7.80(s,8H),8.57(t,1H,J=6.4Hz),8.71(d,1H,J=6.4Hz)9.03-9.08(m,2H) [ka]

[0155] <Synthesis of phenoxy resin a> In a 3000 mL three-necked flask equipped with a Liebig condenser, a calcium chloride tube, and a Teflon® stirring rod connected to a stirring motor, 45 g of 4,4'-(9-fluorenylidene)-diphenol (manufactured by Sigma-Aldrich Japan Co., Ltd.) and 50 g of 3,3',5,5'-tetramethylbiphenol diglycidyl ether (product name: YX-4000H, manufactured by Mitsubishi Chemical Corporation) were dissolved in 1000 mL of N-methylpyrrolidone to prepare the reaction solution. 21 g of potassium carbonate was added to this reaction solution, and the mixture was stirred for 3 hours while heating to 110 °C with a mantle heater. The reaction solution after stirring was added dropwise to a beaker containing 1000 mL of methanol, and the precipitate formed was collected by suction filtration. The filtered precipitate was further washed three times with 300 mL of methanol to obtain 75 g of phenoxy resin a. The molecular weight of the obtained phenoxy resin a was measured using a high-performance liquid chromatograph (Tosoh Corporation, GP8020; columns: Hitachi Chemical Co., Ltd. Gelpack GL-A150S and GLA160S; eluent: tetrahydrofuran; flow rate: 1.0 mL / min). The results, in polystyrene equivalent, were Mn = 15769, Mw = 38045, and Mw / Mn = 2.413.

[0156] <Preparation of conductive particles> A layer of nickel was formed on the surface of cross-linked polystyrene particles to a thickness of 0.15 μm. In this way, conductive particles with an average particle diameter of 3.3 μm, a maximum particle diameter of 3.5 μm, and a specific gravity of 2.7 were obtained.

[0157] <Preparation of adhesive film for circuit connection> The components were mixed in the amounts shown in Table 1 (unit: parts by mass) to prepare a first adhesive composition for forming the first adhesive layer and a second adhesive composition for forming the second adhesive layer. The details of each component in Table 1 are as follows, and the amounts of each component in the table represent the amounts of non-volatile components. Epoxy resin A2: 4-functional naphthalene skeleton epoxy resin (product name: HP4700, manufactured by DIC Corporation) A6:2-functional bisphenol F-type epoxy resin (product name: YL983U, manufactured by Mitsubishi Chemical Corporation) A7: Polyfunctional trisphenolmethane type epoxy resin (product name: jER1032H60, manufactured by Mitsubishi Chemical Corporation) • Hardener B1: Pyridinium salt synthesized above B3: Pyridinium salt synthesized above ·Thermoplastic resin C1: Phenoxy resin a synthesized above C3: Epoxy resin (Product name: jER1010, manufactured by Mitsubishi Chemical Corporation, epoxy equivalent: 3000~5000g / eq) ·Filling material D1: Surface-treated silica particles (hydrolysis product of silica and bis(trimethylsilyl)amine) D2: Surface-treated silica microparticles (hydrolysis product of trimethoxyoctylsilane and silica, trade name: Aerosil R805, manufactured by Evonik Industries AG, used after dilution with organic solvent to 10% by mass of nonvolatile content) D3: Silica particles (manufactured by Admatex Co., Ltd., product name: AdmaFine SE2050) • Coupling agent E1:3-Glycidoxypropyltrimethoxysilane (Trade name: KBM-403, manufactured by Shin-Etsu Chemical Co., Ltd.) • Conductive particles F1: Conductive particles prepared as described above Stabilizer G: 4-Hydroxyphenyldimethylsulfonium sulfate (manufactured by Tokyo Chemical Industry Co., Ltd.)

[0158] A second adhesive composition was applied to a substrate (PET film) to form a second adhesive layer on the substrate. Furthermore, the first adhesive composition was applied on the second adhesive layer to form a first adhesive layer, thereby creating a circuit connection adhesive film in which the first adhesive layer, the second adhesive layer, and the substrate were laminated in this order. In each of the circuit connection adhesive films in Examples 1 and 2, the thickness of the first adhesive layer was 7 μm, and the thickness of the second adhesive layer was also 7 μm.

[0159] <Fabrication of connecting structures> As the first circuit component, an alkali-free glass substrate (OA-11, manufactured by Nippon Electric Glass Co., Ltd., external dimensions: 38 mm x 28 mm, thickness: 0.3 mm) was prepared with a wiring pattern of AlNd (100 nm) / Mo (50 nm) / ITO (100 nm) formed on its surface (pattern width: 19 μm, inter-electrode spacing: 5 μm). As the second circuit component, an IC chip was prepared with bump electrodes arranged in a staggered pattern in two rows (external dimensions: 0.9 mm x 20.3 mm, thickness: 0.3 mm, bump electrode size: 70 μm x 12 μm, inter-bump electrode spacing: 12 μm, bump electrode thickness: 8 μm).

[0160] Connecting structures were fabricated using the circuit connection adhesive films of Examples 1 and 2. First, the first adhesive layer of the circuit connection adhesive film was placed on the first circuit member. A thermocompression bonding device (LD-06, manufactured by Ohashi Seisakusho Co., Ltd.) consisting of a ceramic heater stage and a tool (8 mm x 50 mm) was used at 50°C and 0.98 MPa (10 kgf / cm²). 2Under the conditions of ), it was heated and pressurized for 2 seconds to attach the adhesive film for circuit connection to the first circuit member. Next, the base material on the opposite side of the first circuit member of the adhesive film for circuit connection was peeled off, and alignment was performed between the bump electrodes of the first circuit member and the circuit electrodes of the second circuit member. Next, using a heat tool (8 mm × 45 mm), heating and pressurization were performed at 115°C for 5 seconds and 40 MPa on a pedestal heated to 90°C through a 50-μm-thick PTFE sheet as a buffer material, thereby attaching the second adhesive layer of the adhesive film for circuit connection to the second circuit member to produce a connection structure. The mounting temperature was taken as the actually measured maximum temperature reached by the adhesive film for circuit connection, and the pressure was taken as the value calculated with respect to the total area of the surface where the bump electrodes of the second circuit member face the first circuit member.

[0161] <Evaluation of Connection Resistance> Regarding the connection structure immediately after mounting and after the high-temperature and high-humidity test (after the HAST test), the connection resistances at 14 locations were measured by the four-terminal measurement method, and the average value of the connection resistance values was evaluated. The HAST test was carried out by installing the connection structure in an accelerated life test device (manufactured by HIRAYAMA, product name "PC-242HSR2", conditions: 110°C / 85%RH / 150 hours). The evaluation of the connection resistance was carried out as follows: evaluation A when the connection resistance was less than 10 Ω, evaluation B when it was 10 Ω or more and less than 20 Ω, evaluation C when it was 20 Ω or more and less than 25 Ω, evaluation D when it was 25 Ω or more and less than 30 Ω, and evaluation E when it was 30 Ω or more. The evaluation results are shown in Table 2.

[0162] <DSC Measurement> Differential scanning calorimetry (DSC) was performed on the circuit connection adhesive films of Examples 1 and 2 using a differential scanning calorimeter (product name: DSC Q1000) manufactured by TA Instruments Japan Co., Ltd., under conditions of a nitrogen atmosphere, a heating rate of 10°C / min, and a measurement temperature range of 50 to 300°C. DSC measurements were performed on samples immediately after sampling and on samples after storage at 40°C for 15 hours. Figure 5 shows the DSC measurement results for the sample immediately after sampling of Example 1, Figure 6 shows the DSC measurement results for the sample after storage at 40°C for 15 hours of Example 1, Figure 7 shows the DSC measurement results for the sample immediately after sampling of Example 2, and Figure 8 shows the DSC measurement results for the sample after storage at 40°C for 15 hours of Example 2. In Figures 5 to 8, the dashed lines show the measurement results of heat flow, and the solid lines show the measurement results of derivative heat flow.

[0163] [Table 1]

[0164] [Table 2]

[0165] As shown in Table 2, the pyridinium cation has a benzyl group at position 1 and an electron-withdrawing group at position 2, the benzyl group has an electron-donating group, and the anion is B(C6F5)4 - , or B(C6H3(CF3)2)4 - An adhesive composition containing a pyridinium salt (where the CF3 group is substituted at the 3,5 positions of the phenyl group) was found to be able to cure at low temperatures (115°C) and achieve excellent connection resistance. Furthermore, the anion of the pyridinium salt is B(C6H3(CF3)2)4 - (However, if the CF3 group is substituted at the 3,5 positions of the phenyl group), it was confirmed that excellent connection resistance can be achieved even after HAST testing. [Explanation of symbols]

[0166] 1... Adhesive film for circuit connection, 1A... First adhesive layer, 1B... Second adhesive layer, 2, 2A, 2B... Adhesive components, 3, 3A... Conductive particles, 4... First circuit member, 5... Second circuit member, 6... Connection part, 7... Insulating material, 10... Structure, 41... First circuit board, 42... First electrode, 51... Second circuit board, 52... Second electrode.

Claims

1. (A) epoxy resin and (B) hardener are included, The aforementioned component (B) includes a pyridinium salt, The pyridinium salt comprises a pyridinium cation and an anion. The pyridinium cation has a benzyl group at position 1 and an electron-withdrawing group at position 2. The benzyl group has an electron-donating group, The anion is B(C ６ F ５ ), or B(C ４ － ), or B(C ６ H ３ (CF ３ ) ２ ) ４ － (However, the CF ３ group is substituted at the 3,5 positions of the phenyl group), an adhesive composition.

2. The adhesive composition according to claim 1, further containing conductive particles.

3. A circuit connection adhesive film having a region formed by the adhesive composition according to claim 1 or 2.

4. The device comprises a first region containing a first adhesive component, and a second region adjacent to the first region containing a second adhesive component. A circuit connection adhesive film in which one or both of the first region and the second region are formed with the adhesive composition according to claim 1 or 2.

5. A first circuit member having a first electrode, A second circuit member having a second electrode, A connecting portion is provided between the first circuit member and the second circuit member, and electrically connects the first electrode and the second electrode to each other. Equipped with, A connection structure wherein the connection portion includes a cured product of the circuit connection adhesive film described in claim 3.

6. A method for manufacturing a connection structure, comprising the steps of interposing a circuit connection adhesive film according to claim 3 between a first circuit member having a first electrode and a second circuit member having a second electrode, and then heat-pressing the first circuit member and the second circuit member together to electrically connect the first electrode and the second electrode.

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