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

Abstract

The adhesive composition contains a cationically polymerizable compound, a curing agent and conductive particles, and the cationically polymerizable compound contains an epoxy compound having a bisphenol structure and having a glycidyl group and a glycidoxy group. The adhesive film for circuit connection is provided with an adhesive layer formed by the adhesive composition.

Description

Technical Field

[0001] The present invention relates to an adhesive composition, an adhesive film for circuit connection, a connection structure, and a method for manufacturing the connection structure. Background Art

[0002] Conventionally, various adhesive materials have been used for circuit connection. For example, adhesive films containing conductive particles dispersed in the adhesive have been used to connect liquid crystal displays (LCDs) to liquid crystal driver integrated circuits (ICs), LCDs to tape carrier packages (TCPs), flexible printed circuit boards (FPCs) to TCPs, or FPCs to printed circuit boards (PCBs) (e.g., see Patent Document 1).

[0003] Previous technical literature

[0004] Patent Literature

[0005] Patent Document 1: Japanese Patent Application Laid-Open No. 2014-084400 Summary of the Invention

[0006] Technical issues to be solved by the invention

[0007] In recent years, the demand for connection reliability in mounted devices using adhesive films has continued to increase. To improve connection reliability, mounted devices are required to have HAST resistance, meaning that the adhesive film is unlikely to peel off even after undergoing harsh tests such as the HAST (Highly Accelerated Stress Test).

[0008] Furthermore, according to research conducted by the present inventors, it has been found that the HAST resistance of the adhesive film is improved when the cationically polymerizable compound has multiple cationically polymerizable functional groups. However, even if the adhesive film has HAST resistance, the adhesive film may have poor adhesion.

[0009] Therefore, one object of the present invention is to provide an adhesive composition that achieves excellent connection resistance and excellent adhesion over a wide range of mounting temperatures (130-150°C), even after a HAST test. Furthermore, another object of the present invention is to provide an adhesive film for circuit connection, a connection structure, and a method for producing the connection structure using the adhesive composition.

[0010] Means for solving technical problems

[0011] One aspect of the present invention includes the following [1] to [8].

[0012] [1] An adhesive composition comprising a cationically polymerizable compound, a curing agent, and conductive particles,

[0013] The cationically polymerizable compound includes an epoxy compound having a bisphenol structure and having a glycidyl group and a glycidyloxy group.

[0014] [2] The adhesive composition according to [1], wherein:

[0015] The epoxy compound has 3 or more epoxy groups.

[0016] [3] The adhesive composition according to [1] or [2], wherein:

[0017] The epoxy compound is a compound represented by the following formula (2A),

[0018]

[0019] [4] The adhesive composition according to any one of [1] to [3], wherein

[0020] The curing agent includes at least one of a pyridinium salt and a sulfonium salt.

[0021] [5] An adhesive film for circuit connection, comprising an adhesive layer formed from the adhesive composition according to any one of [1] to [4].

[0022] [6] An adhesive film for circuit connection, comprising a first adhesive layer and a second adhesive layer laminated on the first adhesive layer.

[0023] At least one of the first adhesive layer and the second adhesive layer is a layer formed of the adhesive composition according to any one of [1] to [4].

[0024] [7] A connection structure comprising:

[0025] a first circuit component having a first electrode;

[0026] a second circuit component having a second electrode; and

[0027] a connecting portion disposed between the first circuit component and the second circuit component and electrically connecting the first electrode and the second electrode to each other;

[0028] The connecting portion includes a cured product of the circuit-connecting adhesive film according to [5] or [6].

[0029] [8] A method for manufacturing a connection structure, comprising the following steps:

[0030] The circuit connection adhesive film described in [5] or [6] is interposed between a first circuit component having a first electrode and a second circuit component having a second electrode, and the first circuit component and the second circuit component are thermally pressed to electrically connect the first electrode and the second electrode to each other.

[0031] Effects of the Invention

[0032] According to one aspect of the present invention, an adhesive composition can be provided that achieves excellent connection resistance and excellent adhesion even after a HAST test over a wide range of mounting temperatures (130-150°C), from low to high. Furthermore, according to another aspect of the present invention, an adhesive film for circuit connection, a connection structure, and a method for manufacturing the connection structure using the adhesive composition can be provided. BRIEF DESCRIPTION OF THE DRAWINGS

[0033] Figure 1 This is a schematic cross-sectional view showing one embodiment of an adhesive film for circuit connection.

[0034] Figure 2 This is a schematic cross-sectional view showing one embodiment of an adhesive film for circuit connection.

[0035] Figure 3 It is a schematic cross-sectional view showing one embodiment of a connection structure.

[0036] Figure 4 Yes Figure 3 Schematic cross-sectional view of a method for manufacturing a connection structure. DETAILED DESCRIPTION

[0037] Hereinafter, embodiments of the present invention will be described in detail. However, the present invention is not limited to the following embodiments.

[0038] Within the numerical ranges described in this specification, the upper or lower limit of the numerical range can be replaced with the values shown in the Examples. Furthermore, the lower limit and upper limit of a numerical range can be arbitrarily combined with the lower limit or upper limit of another numerical range, respectively. In expressions such as "A to B," the numerical values A and B at both ends are included in the numerical range as the lower limit and upper limit, respectively. In this specification, expressions such as "10 or more" refer to values 10 and above, and are used as a reference even if the numerical values differ. Furthermore, expressions such as "10 or less" refer to values 10 and below, and are used as a reference even if the numerical values differ. Furthermore, unless otherwise specified, the components and materials exemplified in this specification may be used alone or in combination of two or more. In this specification, when the composition contains multiple substances corresponding to each component, unless otherwise specified, the content of each component in the composition refers to the total amount of the multiple substances present in the composition. Furthermore, in this specification, "(meth)acrylate" refers to at least one of acrylate and its corresponding methacrylate. Furthermore, in this specification, the "epoxy group" refers to a substituent containing an epoxy group in a structure such as a glycidyl group or a glycidyloxy group.

[0039] <Adhesive composition>

[0040] One embodiment of the present invention is an adhesive composition including a cationically polymerizable compound, a curing agent, and conductive particles. The cationically polymerizable compound includes an epoxy compound having a bisphenol structure and having a glycidyl group and a glycidyloxy group.

[0041] (Cationically polymerizable compound)

[0042] The cationic polymerizable compound may be, for example, a compound that is cross-linked by reacting with a curing agent by heating. The cationic polymerizable compound includes an epoxy compound having a bisphenol structure and having a glycidyl group and a glycidyloxy group (hereinafter, the epoxy compound is also referred to as compound A). From the perspective of being more likely to achieve excellent connection resistance even after a HAST test at a wide range of installation temperatures from low to high temperatures (130 to 150° C.) and having better adhesion, compound A may be a compound represented by the following general formula (1A).

[0043]

[0044] [In formula (1A), R 11 、R 12 、R 13 and R 14 Each independently represents a hydrogen atom, an organic group, an organic group having a glycidyl group, or an organic group having a glycidyloxy group, and R 11、R 12 、R 13 and R 14 At least one of them represents an organic group having a glycidyl group, R 11 、R 12 、R 13 and R 14 At least one of them represents an organic group having a glycidyloxy group, R 15 and R 16 Each independently represents a hydrogen atom or an organic group.]

[0045] As R 11 、R 12 、R 13 and R 14 Examples of the organic groups include alkyl, alkylether, 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.

[0046] R 11 、R 12 、R 13 and R 14 From the perspective of achieving excellent connection resistance and better adhesion even after the HAST test in a wide range of mounting temperatures from low to high temperatures (130 to 150°C), R 11 and R 12 Can be different, R 11 and R 12 One of them may be an organic group having a glycidyl group, and the other may be an organic group having a glycidyloxy group. From the perspective of achieving excellent connection resistance and better adhesion even after the HAST test in a wide range of mounting temperatures from low to high temperatures (130 to 150°C), R 13 and R 14 Can be different, R 13 and R 14 One of them may be an organic group having a glycidyl group, and the other may be an organic group having a glycidyloxy group.

[0047] R 15 and / or R 16 In the case of an organic group, examples of the organic group include alkyl, aryl, alkyl ether, and alkenyl groups. These organic groups may have a substituent. The alkyl group may be, for example, a methyl, ethyl, or propyl group. The alkyl group may have a substituent. From the perspective of achieving excellent connection resistance even after a HAST test at a wide range of mounting temperatures from low to high temperatures (130 to 150°C) and better adhesion, R15 and R 16 It may be a hydrogen atom, an alkyl group, or a methyl group.

[0048] The number of epoxy groups possessed by compound A may be 2 or more, 3 or more, or 4 or more, or 10 or less, 8 or less, 6 or less, or 4 or less.

[0049] The number of glycidyl groups in compound A may be 1 or more, or 2 or more, or 5 or less, 4 or less, 3 or less, or 2 or less.

[0050] The number of glycidyloxy groups in compound A may be 1 or more, or 2 or more, or 5 or less, 4 or less, 3 or less, or 2 or less.

[0051] From the viewpoint of more easily achieving excellent connection resistance even after the HAST test and from the viewpoint of better adhesion, the compound A may be a compound having a plurality of glycidyl groups and a plurality of glycidyloxy groups.

[0052] Specifically, the compound A may be a compound represented by the following formula (2A).

[0053]

[0054] The cationically polymerizable compound may contain only compound A, or may contain compound A and a cationically polymerizable compound other than compound A. Examples of cationically polymerizable compounds other than compound A include epoxy compounds (excluding compound A), vinyl ether compounds, and oxetane compounds.

[0055] Examples of the epoxy compound (excluding compound A) include bisphenol A epoxy resin, bisphenol S epoxy resin, bisphenol F epoxy resin, phenol novolac epoxy resin, cresol novolac epoxy resin, bisphenol A novolac epoxy resin, bisphenol F novolac epoxy resin, tetramethyl bisphenol A epoxy resin, 3',4'-epoxycyclohexylmethyl-3,4-epoxycyclohexylcarboxylate (bis-7-oxabicyclo[4,1,0]-heptane), 3,4-epoxycyclohexylmethyl (meth)acrylate, (3,3',4,4'-diepoxy)dicyclohexyl ester, dicyclopentadienyl dimethanol diglycidyl ether, xylene-novolac glycidyl ether, and biphenyl epoxy resins. The epoxy compound may include at least one selected from the group consisting of bisphenol A epoxy resin, tetramethyl bisphenol A epoxy resin, dicyclopentadienyl dimethanol diglycidyl ether, xylene-novolac glycidyl ether, and alicyclic epoxy resin. The epoxy compound may include a glycidyl ether compound. From the perspective of further improving low-temperature curing properties, the epoxy compound may include an alicyclic epoxy resin. Furthermore, from the perspective of easily achieving both low-temperature curing properties and good storage stability, the epoxy compound may not include an alicyclic epoxy resin.

[0056] The cationically polymerizable compound may further contain an epoxy compound having a trisphenolmethane structure (hereinafter, this epoxy compound is also referred to as compound B). Compound B is represented by, for example, the following general formula (1B).

[0057]

[0058] [In formula (1B), R 21 、R 22 and R 23 Each independently represents a hydrogen atom or an organic group, R 21 、R 22 and R 23 At least one of them represents an organic group having an epoxy group, R 24 represents a hydrogen atom or an alkyl group, R 25 represents a hydrogen atom or an organic group.]

[0059] As R 21 、R 22 and R 23 Examples of the organic groups represented by R include alkyl, alkyl ether, and alkenyl. 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, or 8 or less, 6 or less, or 4 or less. 21 、R 22 and R 23 At least one of them may be an organic group having a glycidyl group or an organic group having a glycidyloxy group.21 、R 22 and R 23 From the perspective of achieving excellent connection resistance even after the HAST test in a wide range of mounting temperatures from low to high temperatures (130 to 150°C), R 21 、R 22 and R 23 Any of them may be an organic group having a glycidyl group or an organic group having a glycidyloxy group.

[0060] R 24 In the case of 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 a substituent. From the perspective of achieving excellent connection resistance even after a HAST test at a wide range of mounting temperatures from low to high temperatures (130 to 150°C), R 24 It may be a hydrogen atom.

[0061] As R 25 The organic group represented may be, for example, an alkyl group, an alkyl ether group, or an alkenyl group. The organic group may have a substituent. From the perspective of achieving excellent connection resistance even after a HAST test at a wide range of installation temperatures from low to high temperatures (130 to 150°C), R 25 It can be an alkyl group, an alkyl group with a substituent, or an alkyl group with a phenyl group. The phenyl group may have a substituent, for example, an epoxy group, a glycidyl group, or a glycidyloxy group. From the perspective of achieving excellent connection resistance even after the HAST test at a wide range of mounting temperatures from low to high temperatures (130 to 150°C), R 25 An alkyl group including a phenyl group having a glycidyloxy group may be used.

[0062] The number of epoxy groups possessed by compound B may be 1 or more, 2 or more, or 3 or more, or 15 or less, 12 or less, or 10 or less.

[0063] The epoxy equivalent of compound B may be, for example, 100 to 300 g / eq or 150 to 250 g / eq. The epoxy equivalent is a value measured in accordance with JIS K7236.

[0064] The compound B may be specifically a compound represented by the following formula (2B).

[0065]

[0066] [In formula (2B), n represents an integer of 1 to 3.]

[0067] As oxetane compound, as long as it is the compound with more than 1 oxetane ring structure in the molecule, it is possible to use without restriction.From the viewpoint of further improving low temperature curing, cationic polymerizable compound can include oxetane compound.And, from the viewpoint of being able to easily take into account low temperature curing and good storage stability, cationic polymerizable compound can not include oxetane compound.Cationic polymerizable compound can also include epoxy compound (wherein, except compound A) and oxetane compound while including compound A.And, from the viewpoint of easily taking into account low temperature curing and good storage stability, cationic polymerizable compound can only include one of epoxy compound (wherein, except compound A) and oxetane compound. Regarding the case where only one of an epoxy compound (excluding compound A) and an oxetane compound is included, the following cases can be cited: as a cationically polymerizable compound, one selected from epoxy compounds and oxetane compounds other than compound A is used alone together with compound A; and one selected from epoxy compounds and oxetane compounds other than compound A and a cationically polymerizable compound such as a vinyl ether compound are used simultaneously with compound A.

[0068] Examples of the oxetane compound 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, 3-hydroxyethyl -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, etc.

[0069] From the perspective of fully ensuring the curability of the adhesive composition, the content of the cationically polymerizable compound 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 perspective of ensuring the formability of the adhesive composition, the content of the cationically polymerizable compound 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.

[0070] From the perspective of achieving excellent connection resistance even after a HAST test at a wide range of installation temperatures from low to high temperatures (130 to 150° C.) and from the perspective of better adhesion, the content of the epoxy compound (including compound A) in the cationic polymerizable compound 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. The content of the epoxy compound (including compound A) in the cationic polymerizable compound may be substantially 100% by mass (in a form where the cationic polymerizable compound (including compound A) consists of an epoxy compound).

[0071] From the perspective of achieving excellent connection resistance even after a HAST test over a wide range of mounting temperatures from low to high temperatures (130 to 150°C) and from the perspective of better adhesion, the content of Compound A in the cationically polymerizable compound may be 5% by mass or more, 10% by mass or more, 20% by mass or more, or 30% by mass or more, based on the total mass of the cationically polymerizable compound, and may be substantially 100% by mass (in the case of a cationically polymerizable compound consisting of Compound A). The content of Compound A in the cationically polymerizable compound 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 the cationically polymerizable compound.

[0072] (Curing Agent)

[0073] The curing agent may be any agent capable of curing the cationic polymerizable compound, and may include, for example, an onium salt. Examples of onium salts include pyridinium salts, ammonium salts, sulfonium salts, phosphonium salts, iodonium salts, and diazonium salts. The curing agent may include at least one of a pyridinium salt and a sulfonium salt.

[0074] The onium salt may be, for example, a compound represented by the following general formula (1).

[0075]

[0076] [In formula (1), R 1 、R 2 、R 3 and R 4 Each independently represents a hydrogen atom, a substituted or unsubstituted alkyl group, a substituted or unsubstituted aryl group, a substituted or unsubstituted alkenyl group, a substituted or unsubstituted heterocyclic group, a substituted or unsubstituted alkoxy group, a substituted or unsubstituted aryloxy group or a substituted or unsubstituted heterocyclic group, R 1 、R 2 、R 3 and R 4 Can bond with each other to form a ring structure, X- represents an anion.]

[0077] Examples of the alkyl group include methyl, ethyl, propyl, isopropyl, butyl, isobutyl, n-pentyl, n-hexyl, n-heptyl, and aralkyl groups. Examples of the aralkyl group include benzyl, naphthylmethyl, and cinnamyl groups. These alkyl groups may have a substituent.

[0078] Examples of the aryl group include a phenyl group, a naphthyl group, and a biphenyl group. These aryl groups may have a substituent.

[0079] Examples of the alkenyl group include propenyl, 2-butenyl, 2-pentyl, and 2-hexyl. Examples of the heterocyclic group include pyridyl. Examples of the alkoxy group include methoxy, ethoxy, propoxy, and butoxy. Examples of the aryloxy group include 4-phenylmethoxy, 4-phenylethoxy, and 4-phenoxycarbonylmethyl. Examples of the heterocyclic oxy group include 4-cyclohexyloxy. These groups may have substituents.

[0080] Examples of substituents in the aforementioned alkyl and aryl groups include alkyl groups such as methyl, ethyl, propyl, isopropyl, butyl, isobutyl, tert-butyl, pentyl, and hexyl; aryl groups such as phenyl and naphthyl; alkoxy groups such as methoxy, ethoxy, propoxy, and butoxy; alkoxycarbonyl groups such as acetoxy, propionyloxy, decylcarbonyloxy, and dodecylcarbonyloxy; ester groups such as methoxycarbonyl, ethoxycarbonyl, and benzoyloxy; phenylthio; halogen atoms such as fluorine, chlorine, bromine, and iodine; cyano; nitro; and hydroxyl groups. The positions of these substituents are not particularly limited and may be any position.

[0081] X in formula (1) - represents the counter anion of the nitrogen onium cation. - , for example, SbF6 - 、P F6 - 、B(C6F5)4 - 、Ga(C6F5)4 - 、Ga(C6F5)2F2 - 、Ga(C6F5)F3 - and C(CF3SO2)3 - From the perspective of obtaining better curing properties when the nucleophilicity of the anion is low, SbF6 - 、(C6F5)4B - 、(CF3SO2)3C - .

[0082] From the perspective of lowering the decomposition temperature of the initiator and further improving the curing properties, R 1 、R 2 、R 3and R 4 Any one of (R 1 、R 2 、R 3 and R 4 Only one of ( ) may be a substituted or unsubstituted benzyl, a substituted or unsubstituted naphthylmethyl or a substituted or unsubstituted cinnamyl.

[0083] R 1 、R 2 、R 3 and R 4 can bond to each other to form a ring structure, for example, R 1 、R 2 、R 3 and R 4 Adjacent groups in the ring can be bonded to each other to form a ring structure. As the nitrogen onium cation having a ring structure, for example, a cation represented by the following general formula (2) can be mentioned. As the ring structure Q, a heterocyclic ring, an aromatic ring, a heteroaromatic ring (pyridinium ring, etc.), an alicyclic ring, etc. can be mentioned. The ring structure Q can be, for example, a multi-membered ring such as a four-membered ring, a five-membered ring, a six-membered ring, a seven-membered ring, etc. The ring structure Q can be unsubstituted or have a substituent. As a substituent, for example, the above-mentioned substituents are mentioned for each group such as an alkyl group and an aryl group. m represents 1 or 2. R 5 Can be with R 1 、R 2 、R 3 and R 4 Equivalent groups.

[0084]

[0085] When the curing agent contains an onium salt, from the viewpoint of better storage stability, the onium salt may be a compound that exhibits activity at a temperature of 80 to 250° C., specifically, it may be at least one selected from the group consisting of anilinium salts (anilinium salt compounds) and pyridinium salts (pyridinium salt compounds).

[0086] From the viewpoint of lowering the decomposition temperature and further improving the curability, the anilinium salt may be an N-alkylanilinium salt, an N,N-dialkylanilinium salt, or an N,N,N-trialkylanilinium salt. Specific examples of the anilinium salt include N-benzyl-N,N-dimethylanilinium salt, N-(4-nitrobenzyl)-N,N-dimethylanilinium salt, N-(4-methoxybenzyl)-N,N-dimethylanilinium salt, N-(α-phenylbenzyl)-N,N-dimethylanilinium salt, N-(α-methylbenzyl)-N,N-dimethylanilinium salt, N-(1-naphthylmethyl)-N,N-dimethylanilinium salt, N-cinnamyl-N,N-dimethylanilinium salt, and onium salts having a substituted benzylanilinium cation (e.g., K-PURE CXC-1612 (manufactured by KING Industries, counter anion: SbF6), K-PURE CXC-1738 (manufactured by KING Industries, counter anion: SbF6), and N-PURE CXC-1838 (manufactured by KING Industries, counter anion: SbF6). Industries, counter anion: PF6), K-PURE CXC-1740 (KING Industries, counter anion: SbF6), K-PURE CXC-1741 (KING Industries, counter anion: SbF6), K-PURE CXC-1821 (KING Industries, counter anion: B(C6F5)4), etc. The aromatic ring bonded to the nitrogen atom in these compounds may be unsubstituted or have a substituent. Examples of anilinium salts having a substituent on the aromatic ring include N-(1-naphthylmethyl)-N,N-dimethyl(4-bromophenyl)anilinium salt.

[0087] From the viewpoint of lowering the decomposition temperature and further improving curability, the anilinium salt may be at least one selected from the group consisting of N-benzyl-N,N-dialkylanilinium salts and N-naphthylmethyl-N,N-dialkylanilinium salts.

[0088] The pyridinium salt may be N-benzylpyridinium salt, N-naphthylmethylpyridinium salt, or N-cinnamylpyridinium salt, from the viewpoint of lowering the decomposition temperature and further improving the curability.

[0089] The pyridinium salt may be a pyridinium salt (hereinafter referred to as "pyridinium salt A") having a benzyl group at the 1-position and an electron-withdrawing group at the 2-position, wherein the benzyl group has an electron-donating group. By including pyridinium salt A in the curing agent and an epoxy compound having a bisphenol structure and glycidyl and glycidyloxy groups as the cationically polymerizable compound, the adhesive composition can achieve superior connection resistance.

[0090] The pyridinium salt A may be, for example, a compound represented by the following general formula (3).

[0091]

[0092] [In formula (3), R 6 Represents an electron-withdrawing group, R 7 represents an electron-donating group, X - represents an anion.]

[0093] Examples of the electron-withdrawing group at the 2-position of the pyridinium salt A include cyano, halo, nitro, carbonyl, carboxyl, and sulfo groups. Examples of the halo include fluoro, chloro, bromo, and iodo groups. From the perspective of increasing the activity of the curing agent and curing the adhesive composition in a shorter time, the electron-withdrawing group may be a cyano or halo group, or a cyano or chloro group. The pyridinium salt A may include electron-withdrawing groups other than the electron-withdrawing group at the 2-position. The number of electron-withdrawing groups in the pyridinium salt A may be 3 or less, 2 or less, or 1.

[0094] As all electron-donating groups of the benzyl group configured at the 1-position of the pyridinium salt A, alkyl, alkoxy, hydroxy, amino, alkylamino, etc. can be mentioned. As alkyl, methyl, ethyl, n-propyl, isopropyl, etc. can be mentioned. As alkoxy, methoxy and ethoxy, etc. can be mentioned. From the perspective of being able to increase the activity of the curing agent to cure the adhesive composition in a shorter time, the electron-withdrawing group can be an alkyl or alkoxy group, or a methyl or methoxy group. The benzyl ring can contain multiple electron-donating groups, and the number of electron-donating groups possessed by the benzyl group configured at the 1-position of the pyridinium salt A can be 1 or more, 2 or more, or 3 or more, or 3. The benzyl group configured at the 1-position of the pyridinium salt A can have at least one electron-donating group at the 4-position (the 4-position when the bonding position of the benzyl group to the pyridine ring is set to the 1-position. It is the para position relative to the bonding position of the benzyl group to the pyridine ring).

[0095] When the number of electron-donating groups of the benzyl group at position 1 of pyridinium salt A is 3, the three electron-donating groups may all be alkyl groups or methyl groups. When the bonding position of the benzyl group to the pyridine ring is set to position 1, the pyridinium salt A may have an alkyl group as an electron-donating group at positions 2, 4, and 6 of the benzyl group. In the curing agent, the number of electron-donating groups of the benzyl group at position 1 of pyridinium salt A is 3, and the electron-donating groups all include pyridinium salts as alkyl (or methyl) groups, thereby the adhesive film using such a curing agent has excellent physical properties (such as elastic modulus). Therefore, the adhesive film using such a curing agent, for example, can take into account the excellent adhesion to circuit components and the excellent peelability of the substrate of the self-adhesive film. Furthermore, adhesive films using this curing agent exhibit excellent storage stability, maintaining excellent adhesion to circuit components and excellent releasability from the adhesive film's substrate even when the adhesive film is stored for a certain period of time (e.g., 15 hours at 40°C). This is believed to be due to the number of electron-donating groups possessed by the benzyl group at the 1-position of the pyridinium salt A, which creates a well-balanced structure that maintains low-temperature curability while preventing degradation during storage for a certain period of time (e.g., 15 hours at 40°C) (excellent storage stability).

[0096] Examples of the pyridinium cation of the 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. From the perspective of being able to cure the adhesive composition in a shorter time, the pyridinium cation of the 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.

[0097] The anion of pyridinium salt A can be SbF6 - PF6 - PF X (CF3) 6-X - (wherein X is an integer from 1 to 5), BF4 - 、B(C6F5)4- 、RSO3 - (wherein R is an alkyl group having 1 to 3 carbon atoms, or a substituted or unsubstituted aryl group), C(SO2CF3)3 - 、N(SO2CF3)2 - 、O(SO2CF3) - 、B(C6H3(CF3)2)4 - (wherein the CF3 group is substituted at the 3- and 5-positions of the phenyl group), etc. From the viewpoint of excellent connection resistance even after a high temperature and high humidity test (e.g., 85°C, 85% RH, 250 hours), the anion of the pyridinium salt A may be B(C6F5)4 - .

[0098] Pyridinium salt A may be a compound formed by combining the above-mentioned pyridinium cation and the above-mentioned anion. That is, pyridinium salt A may contain at least any one of the above-mentioned pyridinium cations and any one of the above-mentioned anions. From the perspective of being able to cure the adhesive composition in a shorter time, pyridinium salt A may be at least one selected from the group consisting of 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, and 2-chloro-1-(2,4,6-trimethylbenzyl)pyridinium tetrakis(pentafluorophenyl)borate.

[0099] The content of pyridinium salt A in the curing agent may be 80 mass % or more, 90 mass % or more, or 95 mass % or more, or 100 mass % (in a form where the curing agent substantially consists of pyridinium salt A), based on the total mass of the curing agent.

[0100] The curing agent may contain a pyridinium salt other than pyridinium salt A. The content of the pyridinium salt other than pyridinium salt A in the curing agent may be 20% by mass or less, 10% by mass or less, or 5% by mass or less, based on the total mass of the curing agent, or may be 0% by mass (in a form in which the curing agent substantially consists of pyridinium salt A).

[0101] A curing agent containing a pyridinium salt A can be obtained, for example, by a production method comprising the following steps: 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, and an alkali metal iodide salt (e.g., sodium iodide) in a solvent (e.g., acetonitrile) to obtain a pyridinium iodide having a pyridine ring and a benzene ring; and reacting the obtained pyridinium iodide and an anion salt in a solvent (e.g., dichloromethane) to obtain a pyridinium salt A.

[0102] The pyridine compound having an electron-withdrawing group at the 2-position may be any of the pyridine compounds having the aforementioned electron-withdrawing group at the 2-position, for example, 2-cyanopyridine or 2-chloropyridine.

[0103] The benzyl chloride compound having an electron-donating group may be any of the above-mentioned benzyl chloride compounds, for example, 4-methoxybenzyl chloride or 2,4,6-trimethylbenzyl chloride. The benzyl bromide compound having an electron-donating group may be any of the above-mentioned benzyl bromide compounds, for example, 4-methoxybenzyl bromide or 2,4,6-trimethylbenzyl bromide.

[0104] The anion salt may be any compound that can introduce the anion of the pyridinium salt A, and examples thereof include lithium salts, sodium salts, potassium salts, and cesium salts of the anion of the pyridinium salt A described above.

[0105] In the step of obtaining pyridinium iodide, the reaction can be carried out at room temperature (20-30° C.), for example. The reaction time can be, for example, 10-50 hours or 20-30 hours. After the reaction is completed, the obtained pyridinium iodide can be washed with acetone, distilled water, or the like, and then vacuum-dried to remove the solvent.

[0106] In the step 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 is defined as the ratio of the amount actually obtained to the maximum amount of pyridinium iodide that can be obtained from the raw materials used to synthesize pyridinium iodide.

[0107] In the step of obtaining pyridinium salt A, the reaction can be carried out at room temperature (20-30° C.), for example. The reaction time can be, for example, 1-15 hours or 1-5 hours. After the reaction, the obtained pyridinium salt A can be washed with acetone, distilled water, or the like, and then vacuum-dried to remove the solvent.

[0108] In the step of obtaining pyridinium salt A, the yield of pyridinium salt A can be 70% or more, 80% or more, or 85% or more. The yield of pyridinium salt A is defined as the ratio of the amount actually obtained to the maximum amount of pyridinium salt A that can be obtained from pyridinium iodide used to synthesize pyridinium salt A.

[0109] Regarding obtaining the pyridinium salt A, it can be obtained by using nuclear magnetic resonance spectroscopy ( 1 The obtained compound can be confirmed by measuring H-NMR. Specifically, it can be confirmed by the method described in the examples described later.

[0110] The sulfonium salt may be, for example, a compound represented by the following formula (4).

[0111]

[0112] [In formula (4), R 8 and R 9 Each independently represents a hydrogen atom, an alkyl group having 1 to 20 carbon atoms, or an organic group containing a substituted or unsubstituted aromatic hydrocarbon group, R 10 represents an alkyl group having 1 to 6 carbon atoms, X - represents an anion.]

[0113] From the viewpoint of achieving both storage stability and low-temperature activity, the sulfonium salt may be an aromatic sulfonium salt. 8 and R 9 At least one of them may be an organic group including a substituted or unsubstituted aromatic hydrocarbon group.

[0114] X in formula (4) - For example, SbF6 - 、(C6F5)4B - 、(CF3SO2)3C - .

[0115] Examples of the sulfonium salt include 1-naphthylmethylmethyl-p-hydroxyphenylsulfonium salt, 4-hydroxy-2-methylphenylmethylnaphth-1-ylmethylsulfonium salt, 3-methyl-2-butenyldimethylsulfonium salt, 3-methyl-2-butenyltetramethylenesulfonium salt, cinnamyldimethylsulfonium salt, and cinnamyltetramethylenesulfonium salt.

[0116] From the perspective of fully promoting the curing reaction, the content of the curing agent in the adhesive composition can 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 perspective of improving the physical properties of the cured product, the content of the curing agent in the adhesive composition can 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 these perspectives, the content of the curing agent in the adhesive composition can be 1 to 20% by mass, based on the total mass of the adhesive composition.

[0117] To fully promote the curing reaction, the content of the curing agent in the adhesive composition can 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 the conductive particles. To improve the physical properties of the cured product, the content of the curing agent in the adhesive composition can 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 the conductive particles. From these perspectives, the content of the curing agent in the adhesive composition can be 1 to 30% by mass, based on the total mass of the adhesive composition excluding the conductive particles.

[0118] From the perspective of fully promoting the curing reaction, the content of the curing agent in the adhesive composition can 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 the conductive particles and the filler. From the perspective of improving the physical properties of the cured product, the content of the curing agent in the adhesive composition can 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 the conductive particles and the filler. From these perspectives, the content of the curing agent in the adhesive composition can be 1 to 30% by mass, based on the total mass of the adhesive composition excluding the conductive particles and the filler.

[0119] From the perspective of fully promoting the curing reaction, the content of the curing agent in the adhesive composition can 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 the cationically polymerizable compound. From the perspective of improving the physical properties of the cured product, the content of the curing agent in the adhesive composition can 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 the cationically polymerizable compound. From these perspectives, the content of the curing agent in the adhesive composition can be 1 to 40 parts by mass, based on 100 parts by mass of the cationically polymerizable compound.

[0120] (Conductive particles)

[0121] The adhesive composition contains conductive particles. The conductive particles are not particularly limited as long as they are conductive. 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 composed of non-conductive glass, ceramic, or plastic (such as polystyrene) and a coating layer composed of the aforementioned metal or conductive carbon that coats the core. The conductive particles may be coated conductive particles because they are easily deformed by heating and / or pressurizing, increasing the contact area between the electrodes and the conductive particles when electrically connecting the electrodes, and further improving the conductivity between the electrodes.

[0122] From the perspective of excellent dispersibility and conductivity, the average particle size of the conductive particles can be 1 μm or larger, 2 μm or larger, or 2.5 μm or larger. From the perspective of ensuring insulation between adjacent electrodes, the average particle size of the conductive particles can be 20 μm or smaller, 15 μm or smaller, 10 μm or smaller, 8 μm or smaller, 6 μm or smaller, 5.5 μm or smaller, or 5 μm or smaller. From these perspectives, the average particle size of the conductive particles can be 1-20 μm, 1-15 μm, 1-10 μm, 1-8 μm, or 1-6 μm.

[0123] The average particle size of the conductive particles was determined by observing 300 conductive particles contained in the adhesive composition using a scanning electron microscope (SEM). The particle size of each conductive particle was measured and the average particle size of the 300 conductive particles was obtained. If the conductive particles were not spherical, the particle size of the conductive particles was determined as the diameter of a circle circumscribing the conductive particles in the SEM observation image.

[0124] From the viewpoint of obtaining stable connection resistance, the particle density of the conductive particles in the adhesive composition may be 100 particles / mm 2 Above, 1000 pieces / mm 2 Above or 3000 pieces / mm 2 From the viewpoint of ensuring insulation between adjacent electrodes, the particle density of the conductive particles in the adhesive composition may be 100,000 particles / mm 2 Below, 50,000 pieces / mm 2 Below or 30,000 pieces / mm 2 From these viewpoints, the particle density of the conductive particles in the adhesive composition may be 100 to 100,000 particles / mm 2 1000~50000 pieces / mm 2 or 3000~30000 pieces / mm 2 .

[0125] The content of the conductive particles may be 10% by mass or greater, 20% by mass or greater, or 25% by mass or greater based on the total mass of the adhesive composition. The content of the 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.

[0126] The content of the conductive particles based on 100 parts by mass of the cationically polymerizable compound 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. The content of the conductive particles based on 100 parts by mass of the cationically polymerizable compound 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.

[0127] The adhesive composition may further contain other components in addition to the above components. Other components may include a thermoplastic resin, a coupling agent, a filler, a stabilizer, a colorant, an antioxidant, and a curing agent other than the curing agent containing pyridinium salt A. The adhesive composition may further contain a free radical polymerizable compound and a free radical polymerization initiator.

[0128] (thermoplastic resin)

[0129] The adhesive composition may further contain a thermoplastic resin. By containing a thermoplastic resin, the adhesive composition can be easily formed into a film. Examples of thermoplastic resins include phenoxy resins, epoxy resins, polyester resins, polyamide resins, polyurethane resins, polyesterurethane resins, and acrylic rubbers. These may be used alone or in combination of two or more. If the epoxy equivalent weight of the epoxy resin is 400 g / eq or greater, it is considered a thermoplastic resin.

[0130] The weight average molecular weight (Mw) of the thermoplastic resin may be, for example, 5,000 or more, 10,000 or more, 20,000 or more, or 40,000 or more, or 200,000 or less, 100,000 or less, 80,000 or less, or 60,000 or less. The weight average molecular weight of the thermoplastic resin is a value measured by gel permeation chromatography (GPC) and converted using a calibration curve based on standard polystyrene.

[0131] The content of the thermoplastic resin 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 content of the thermoplastic resin may be 60% by mass or less, 50% by mass or less, 40% by mass or less, 30% by mass or less, or 20% by mass or less, based on the total mass of the adhesive composition.

[0132] The content of the thermoplastic resin based on 100 parts by mass of the cationically polymerizable compound 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. The content of the thermoplastic resin based on 100 parts by mass of the cationically polymerizable compound may be 150 parts by mass or less, 120 parts by mass or less, 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.

[0133] (Coupling agent)

[0134] The adhesive composition may further contain a coupling agent. The adhesive composition can further improve adhesion by containing a coupling agent. The coupling agent may be a silane coupling agent, such as vinyl trimethoxysilane, vinyl triethoxysilane, 3-glycidoxypropyl trimethoxysilane, 3-glycidoxypropyl methyl diethoxysilane, 3-(methyl) acryloxypropyl methyl dimethoxysilane, 3-(methyl) acryloxypropyl trimethoxysilane, 3-(methyl) acryloxypropyl methyl diethoxysilane, 3-(methyl) acryloxypropyl triethoxysilane, N-2-(aminoethyl)-3-aminopropyl methyl dimethoxysilane, N-phenyl-3-aminopropyl trimethoxysilane, 3-ureidopropyl triethoxysilane, 3-mercaptopropyl trimethoxysilane, 3-isocyanate propyl triethoxysilane and their condensates. These may be used alone or in combination of two or more.

[0135] Based on the total mass of the adhesive composition, the coupling agent content may be 0.5 mass% or more, 1 mass% or more, or 2 mass% or more. Based on the total mass of the adhesive composition, the coupling agent content may be 15 mass% or less, 10 mass% or less, or 5 mass% or less.

[0136] The coupling agent content can 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 the cationically polymerizable compound. The coupling agent content can 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 the cationically polymerizable compound.

[0137] (Filling material)

[0138] The adhesive composition may further contain a filler. The adhesive composition contains a filler, thereby further improving the connection reliability. As a filler, a non-conductive filler (e.g., non-conductive particles) can be mentioned. The filler can be any of an inorganic filler and an organic filler.

[0139] Examples of the inorganic filler 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 alone or in combination of two or more.

[0140] Examples of the organic filler include silicone particles, methacrylate-butadiene-styrene particles, acrylic-silicone particles, polyamide particles, and polyimide particles, etc. These may be used alone or in combination of two or more.

[0141] From the perspective of improving film formability and the reliability of the connected structure, the filler can be an inorganic filler or silica particles. The silica particles can be crystalline silica particles or amorphous silica particles, and these silica particles can be synthetic. The silica can be synthesized by a dry process or a wet process. The silica particles can include at least one selected from the group consisting of fumed silica particles and sol-gel silica particles.

[0142] From the viewpoint of excellent dispersibility in the adhesive component, the silica particles can be surface-treated silica particles. The surface-treated silica particles are, for example, hydrophobized by a silane compound or a silane coupling agent to form a hydroxyl group on the surface of the silica particles. The surface-treated silica particles can be, for example, silica particles surface-treated by a silane compound such as an alkoxysilane compound, a disilazane compound, or a siloxane compound, or can be silica particles surface-treated by a silane coupling agent.

[0143] Examples of the alkoxysilane compound 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.

[0144] Examples of the disilazane compound 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.

[0145] Examples of the siloxane compound include tetradecamethylcycloheptasiloxane, decamethylcyclopentasiloxane, hexaphenylcyclosiloxane, octamethylcyclononasiloxane, hexadecylcyclooctasiloxane, dodecamethylcyclohexasiloxane, octaphenylcyclotetrasiloxane, hexamethylcyclotrisiloxane, heptaphenyldisiloxane, tetradecamethylhexasiloxane, dodecamethylpentasiloxane, hexamethyldisiloxane, decamethyltetrasiloxane, hexamethoxydisiloxane, and octamethyltrisiloxane. siloxane, 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-glycidyloxypropyl)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-oxabicyclo[4 .1.0]heptane-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 and octaphenyloctasilsesquioxane, etc.

[0146] Examples of the silane coupling agent include vinyltrimethoxysilane, vinyltriethoxysilane, 2-(3,4-epoxycyclohexyl)-ethyltrimethoxysilane, 3-glycidoxypropylmethyldimethoxysilane, 3-glycidoxypropyltrimethoxysilane, 3-glycidoxypropylmethyldiethoxysilane, 3-glycidoxypropyltriethoxysilane, p-phenylenediaminetrimethoxysilane, 3-methacryloxypropylmethyldimethoxysilane, 3-methacryloxypropyltrimethoxysilane, 3-methacryloxypropylmethyldiethoxysilane, 3-methacryloxypropyltriethoxysilane, 3- Acryloyloxypropyltrimethoxysilane, N-2-(aminoethyl)-3-aminopropylmethyldimethoxysilane, N-2-(aminoethyl)-3-aminopropyltrimethoxysilane, 3-aminopropyltrimethoxysilane, 3-aminopropyltriethoxysilane, 3-triethoxysilyl-N-(1,3-dimethyl-butylidene)propylamine, N-phenyl-3-aminopropyltrimethoxysilane, tris-(trimethoxysilylpropyl)isocyanurate, 3-ureidopropyltrialkoxysilane, 3-mercaptopropylmethyldimethoxysilane, 3-mercaptopropyltrimethoxysilane, 3-isocyanatepropyltriethoxysilane and 3-trimethoxysilylpropylsuccinic anhydride, etc.

[0147] Silica particles surface-treated with a silane compound or a silane coupling agent can be surface-treated with a silane compound such as 3-methacryloxypropyltrimethoxysilane, vinyltrimethoxysilane, or trimethoxyphenylsilane to further hydrophobize the hydroxyl residues on the surface of the silica particles.

[0148] When the adhesive composition is used as an adhesive film for circuit connection, and the adhesive film for circuit connection is pressure-bonded, from the viewpoint of facilitating fluidity control and improving the mechanical properties and water resistance of the connection structure after pressure bonding, the surface-treated silica particles may include at least one selected from the group consisting of a reaction product (hydrolyzate) of silica and trimethoxyoctylsilane, a reaction product of silica and dimethylsiloxane, a reaction product of silica or silica and dichloro(dimethyl)silane, a reaction product (hydrolyzate) of silica and bis(trimethylsilyl)amine, and a reaction product of silica and hexamethyldisilazane. They may also include at least one selected from the group consisting of a reaction product of silica and trimethoxyoctylsilane and a reaction product of silica and bis(trimethylsilyl)amine.

[0149] 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.

[0150] The content of the filler can 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 the cationically polymerizable compound. The content of the filler can 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 the cationically polymerizable compound.

[0151] Examples of free radical polymerizable compounds include acrylic acid compounds. Examples of acrylic acid compounds include (meth)acrylic acid compounds, (meth)acrylate compounds, and imide compounds thereof. These may be used in the form of monomers or oligomers, or both monomers and oligomers may be used. The free radical polymerizable compounds may be used alone or in combination of two or more.

[0152] 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-(acryloyloxymethoxy)phenyl]propane, and 2,2-bis[4-(acryloyloxypolyethoxy)phenyl]propane; dicyclopentenyl acrylate, tricyclodecyl acrylate, and tris(acryloyloxyethyl)isocyanurate.

[0153] The radical polymerization initiator can be a radical polymerization initiator that generates free radicals by light or heat. As the radical polymerization initiator, organic peroxides and azo compounds can be mentioned. As the organic peroxide, peroxyesters, dialkyl peroxides, diacyl peroxides, peroxydicarbonates, peroxyketals, hydroperoxides and silicon-based peroxides can be mentioned. The radical polymerization initiator can be used alone or in combination of two or more.

[0154] Examples of the peroxyester include cumyl peroxypivalate, 1,1,3,3-tetramethylbutyl peroxypivalate, 1-cyclohexyl-1-methylethyl peroxypivalate, tert-hexyl peroxypivalate, tert-butyl peroxypivalate, 1,1,3,3-tetramethylbutyl peroxy-2-ethylhexanoate, 2,5-dimethyl-2,5-di(2-ethylhexanoylperoxy)hexane, 1-cyclohexyl-1-methylethyl peroxy-2-ethylhexanoate, and tert-butyl peroxypivalate. L-hexyl peroxide, L-butyl peroxy-2-ethylhexanoate, tert-butyl isobutyrate, 1,1-bis(tert-butylperoxy)cyclohexane, tert-hexyl peroxyisopropyl monocarbonate, tert-butyl peroxy-3,5,5-trimethylhexanoate, tert-butyl peroxylaurate, 2,5-dimethyl-2,5-di(m-tolylperoxy)hexane, tert-butyl isopropyl monocarbonate, tert-butyl peroxy-2-ethylhexyl monocarbonate, tert-hexyl peroxybenzoate and tert-butyl peroxyacetate, etc.

[0155] Examples of the dialkyl peroxide include α,α′-bis(tert-butylperoxy)diisopropylbenzene, diisopropylphenyl peroxide, 2,5-dimethyl-2,5-di(tert-butylperoxy)hexane, and tert-butyldiisopropylphenyl peroxide. Examples of the hydroperoxide include diisopropylbenzene hydroperoxide and cumene hydroperoxide.

[0156] Examples of the diacyl peroxide include isobutyl peroxide, 2,4-dichlorobenzoyl peroxide, 3,5,5-trimethylhexanoyl peroxide, octanoyl peroxide, lauroyl peroxide, stearyl peroxide, stearyl peroxide, benzoyltoluene peroxide, and benzoyl peroxide.

[0157] Examples of the peroxydicarbonate include di-n-propyl peroxydicarbonate, diisopropyl peroxydicarbonate, bis(4-tert-butylcyclohexyl)peroxydicarbonate, di-2-ethoxymethoxyperoxydicarbonate, di(2-ethylhexylperoxy)dicarbonate, dimethoxybutyl peroxydicarbonate, and di(3-methyl-3-methoxybutylperoxy)dicarbonate.

[0158] Specific examples of the peroxyketal include 1,1-bis(tert-hexylperoxy)-3,3,5-trimethylcyclohexane, 1,1-bis(tert-hexylperoxy)cyclohexane, 1,1-bis(tert-hexylperoxy)-3,3,5-trimethylcyclohexane, 1,1-(tert-hexylperoxy)cyclododecane, and 2,2-bis(tert-butylperoxy)decane.

[0159] Specific examples of the silicon-based peroxides include tert-butyltrimethylsilyl peroxide, bis(tert-butyl)dimethylsilyl peroxide, tert-butyltrivinylsilyl peroxide, bis(tert-butyl)divinylsilyl peroxide, tri(tert-butyl)vinylsilyl peroxide, tert-butyltriallylsilyl peroxide, bis(tert-butyl)diallylsilyl peroxide, and tri(tert-butyl)allylsilyl peroxide.

[0160] Adhesive films for circuit connection

[0161] The adhesive composition may be in the form of a film. That is, another embodiment of the present invention is an adhesive film for circuit connection, which contains compound A and a curing agent. The adhesive film for circuit connection may contain conductive particles.

[0162] From the viewpoint of obtaining stable connection resistance, the particle density of the conductive particles in the circuit connection adhesive film may be 100 particles / mm 2 Above, 1000 pieces / mm 2 Above or 3000 pieces / mm 2 From the viewpoint of ensuring insulation between adjacent electrodes, the particle density of the conductive particles in the circuit-connecting adhesive film may be 100,000 particles / mm 2 Below, 50,000 pieces / mm 2 Below or 30,000 pieces / mm 2 From these viewpoints, the particle density of the conductive particles in the circuit-connecting adhesive film may be 100 to 100,000 particles / mm. 2 1000~50000 pieces / mm 2 or 3000~30000 pieces / mm 2 .

[0163] The content of the conductive particles may be 10% by mass or greater, 20% by mass or greater, or 25% by mass or greater, based on the total mass of the adhesive film for circuit connection. The content of the 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.

[0164] The content of the conductive particles based on 100 parts by mass of the cationically polymerizable compound 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. The content of the conductive particles based on 100 parts by mass of the cationically polymerizable compound 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.

[0165] From the perspective of fully ensuring the curability of the circuit-connecting adhesive film, the content of the cationically polymerizable compound in the circuit-connecting adhesive film can 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-connecting adhesive film. From the perspective of ensuring the formability of the circuit-connecting adhesive film, the content of the cationically polymerizable compound in the circuit-connecting adhesive film can 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-connecting adhesive film. From these perspectives, the content of the cationically polymerizable compound in the circuit-connecting adhesive film can be 10 to 60% by mass, based on the total mass of the circuit-connecting adhesive film.

[0166] From the perspective of fully ensuring the curability of the adhesive film for circuit connection, the content of compound A in the adhesive film for circuit connection may be 5% by mass or more, 10% by mass or more, 12% by mass or more, or 15% by mass or more, based on the total mass of the adhesive film for circuit connection. From the perspective of ensuring the formability of the adhesive film for circuit connection, the content of compound A in the adhesive film for circuit connection may be 50% by mass or less, 40% by mass or less, 35% by mass or less, 30% by mass or less, 25% by mass or less, 22% by mass or less, or 20% by mass or less, based on the total mass of the adhesive film for circuit connection. From these perspectives, the content of compound A in the adhesive film for circuit connection may be 5-50% by mass or 10-50% by mass, based on the total mass of the adhesive film for circuit connection.

[0167] To fully promote the curing reaction, the curing agent content in the adhesive film for circuit connection can 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 film for circuit connection. To improve the physical properties of the cured product, the curing agent content in the adhesive film for circuit connection can 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 film for circuit connection. From these perspectives, the curing agent content in the adhesive film for circuit connection can be 1 to 20% by mass, based on the total mass of the adhesive film for circuit connection.

[0168] To fully promote the curing reaction, the curing agent content in the circuit-connecting adhesive film can 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-connecting adhesive film excluding the conductive particles. To improve the physical properties of the cured product, the curing agent content in the circuit-connecting adhesive film can 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-connecting adhesive film excluding the conductive particles. From these perspectives, the curing agent content in the circuit-connecting adhesive film can be 1 to 30% by mass, based on the total mass of the circuit-connecting adhesive film excluding the conductive particles.

[0169] To fully promote the curing reaction, the curing agent content in the circuit-connecting adhesive film can 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-connecting adhesive film excluding the conductive particles and filler. To improve the physical properties of the cured product, the curing agent content in the circuit-connecting adhesive film can 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-connecting adhesive film excluding the conductive particles and filler. From these perspectives, the curing agent content in the circuit-connecting adhesive film can be 1 to 30% by mass, based on the total mass of the circuit-connecting adhesive film excluding the conductive particles and filler.

[0170] The content of the thermoplastic resin in the adhesive film for circuit connection 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 film for circuit connection. The content of the thermoplastic resin in the adhesive film for circuit connection 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 adhesive film for circuit connection.

[0171] The coupling agent content in the adhesive film for circuit connection 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 adhesive film for circuit connection. The coupling agent content in the adhesive film for circuit connection 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 adhesive film for circuit connection.

[0172] The content of the filler in the adhesive film for circuit connection 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 connection. The content of the filler in the adhesive film for circuit connection 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.

[0173] The content of each component in the circuit-connecting adhesive film based on 100 parts by mass of the cationically polymerizable compound may be within the same range as the content of each component in the adhesive composition based on 100 parts by mass of the cationically polymerizable compound.

[0174] The adhesive film for circuit connection may be a single layer or a multilayer structure having a plurality of layers stacked together. When the adhesive film for circuit connection has a multilayer structure, the adhesive film for circuit connection may, for example, include a first adhesive layer containing compound A and a curing agent and a second adhesive layer other than the first adhesive layer. That is, the adhesive film for circuit connection may include a first adhesive layer and a second adhesive layer stacked on the first adhesive layer. At least one of the first adhesive layer and the second adhesive layer may contain compound A, a curing agent, and conductive particles. When the adhesive film for circuit connection has a multilayer structure, the content of the above-mentioned components in each layer may be within the above-mentioned content range based on the total mass of each layer.

[0175] An adhesive film for circuit connection can have multiple regions containing different types and contents of ingredients. For example, the adhesive film can include a first region and a second region disposed on the first region. The first region may be a region containing Compound A and a curing agent. Specifically, the adhesive film for circuit connection can include: a first region formed from a first adhesive composition containing Compound A and a curing agent; and a second region formed from a second adhesive composition disposed on the first region. When the adhesive film for circuit connection has multiple regions, the contents of the aforementioned ingredients in each region can be within the aforementioned ranges, based on the total mass of each region.

[0176] The circuit-connecting adhesive film can be provided on a substrate (e.g., a PET film), etc. The circuit-connecting adhesive film with a substrate can be produced by coating an adhesive composition containing conductive particles on a substrate using, for example, a knife coater, a roll coater, an applicator, a comma coater, a die coater, or the like.

[0177] Figure 1 1 is a schematic cross-sectional view showing an adhesive film for circuit connection according to one embodiment. Figure 1 As shown, in one embodiment, the circuit-connecting adhesive film 1 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 a compound A and a curing agent. The circuit-connecting adhesive film 1 may be in an uncured state or a partially cured state.

[0178] The thickness of the circuit-connecting adhesive film 1 may be, for example, 3 μm or more or 5 μm or more, or 30 μm or less or 20 μm or less.

[0179] In one embodiment, the circuit connection adhesive film may have a multilayer structure having two or more layers, for example, Figure 2 As shown, the adhesive film 1 for circuit connection can be a double-layer structure having a layer 1A containing conductive particles 3A (a first adhesive layer formed by an adhesive component 2A and conductive particles 3A dispersed in the adhesive component 2A), and a layer 1B not containing conductive particles (a second adhesive layer formed by an adhesive component 2B). In this case, the first adhesive layer 1A can be a layer formed by an adhesive composition (a first adhesive composition) containing a compound A, a curing agent, and conductive particles. The second adhesive layer 1B can be a layer formed by an adhesive composition (a second adhesive composition) containing a compound A and a curing agent. The types and contents of the components contained in the second adhesive layer 1B can be the same as or different from those in the first adhesive layer 1A. The first adhesive layer 1A and the second adhesive layer 1B of the adhesive film 1 for circuit connection can be in an uncured state or a partially cured state, respectively.

[0180] The thickness of the first adhesive layer 1A can be, for example, 1 μm or more or 3 μm or more, or 15 μm or less or 10 μm or less. The thickness of the second adhesive layer 1B can be, for example, 1 μm or more or 3 μm or more, or 20 μm or less or 15 μm or less. The thickness of the first adhesive layer 1A can 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) can be 0.1 or more or 0.3 or less, or 1.5 or less or 0.5 or less.

[0181] The circuit-connecting adhesive film may be an anisotropically conductive adhesive film (anisotropic conductive film) or a conductive adhesive film without anisotropic conductivity.

[0182] <Connection structure>

[0183] Another embodiment of the present invention is a connection structure comprising: a first circuit component having a first electrode; a second circuit component having a second electrode; and a connection portion, arranged between the first circuit component and the second circuit component, electrically connecting the first electrode and the second electrode to each other, the connection portion comprising a cured product of the above-mentioned circuit connection adhesive film.

[0184] Figure 3 : is a schematic cross-sectional view showing one embodiment of a connection structure. Figure 3As shown, the structure 10 includes a first circuit component 4 and a second circuit component 5 facing each other, and a connection portion 6 connecting the first circuit component 4 and the second circuit component 5 .

[0185] The first circuit member 4 includes a first circuit board 41 and a first electrode 42 formed on a principal surface 41a of the first circuit board 41. The second circuit member 5 includes a second circuit board 51 and a second electrode 52 formed on a principal surface 51a of the second circuit board 51.

[0186] The first circuit component 4 and the second circuit component 5 are not particularly limited as long as they are components having electrodes required for electrical connection. Examples of components (circuit components, etc.) having electrodes include inorganic substrates such as semiconductors, glass, and ceramics; polyimide substrates such as TCP, FPC, and COF; substrates having electrodes formed on films such as polycarbonate, polyester, and polyethersulfone; and printed wiring boards. A combination of these may be used.

[0187] Connecting portion 6 comprises a cured product of circuit-connecting adhesive film 1, an insulating substance 7 as a cured product of adhesive component 2, and conductive particles 3. Conductive particles 3 are arranged not only between the opposing first electrode 42 and second electrode 52, but also between the main surface 41a of first circuit board 41 and the main surface 51a of second circuit board 51. In structure 30, first electrode 42 and second electrode 52 are electrically connected via conductive particles 3. That is, conductive particles 3 are in contact with both first electrode 42 and second electrode 52.

[0188] In the structure 10, as described above, the opposing first electrode 42 and second electrode 52 are electrically connected via the conductive particles 3. Therefore, the connection resistance between the first electrode 42 and the second electrode 52 is sufficiently reduced. Consequently, the flow of current between the first electrode 42 and the second electrode 52 can be smoothed, allowing the functions of the first circuit component 4 and the second circuit component 5 to be fully utilized.

[0189] <Method for Manufacturing Connected Structure>

[0190] Another embodiment of the present invention is a method for manufacturing a connection structure, which includes the following steps: placing the above-mentioned circuit connection adhesive film between a first circuit component having a first electrode and a second circuit component having a second electrode, hot-pressing the first circuit component and the second circuit component, and electrically connecting the first electrode and the second electrode to each other.

[0191] Figure 4 Schematic cross-sectional view showing one embodiment of a method for manufacturing a connection structure. Figure 4As shown in (a), first, prepare the first circuit component 4 and the circuit connection adhesive film 1. Then, the circuit connection adhesive film 1 is arranged on the main surface 41a of the first circuit component 4. When the circuit connection adhesive film 1 is laminated on a substrate (not shown), the circuit connection adhesive film 1 side of the substrate is directed toward the first circuit component 4, and the laminate is arranged on the first circuit component 4. Figure 2 As shown, when the circuit connection adhesive film 1 has a first adhesive layer 1A and a second adhesive layer 1B, from the viewpoint of increasing the number of conductive particles captured between opposing electrodes, it is preferably configured so that the side of the adhesive layer (first adhesive layer 1A) containing the conductive particles is in contact with the main surface 41a of the first circuit component 4.

[0192] Then, the circuit connection adhesive film 1 is Figure 4 Press in the directions of arrows A and B in (a) and temporarily connect the circuit-connecting adhesive film 1 to the first circuit member 4 (refer to Figure 4 (b)). At this time, heating may be performed while applying pressure.

[0193] Then, if Figure 4 As shown in (c), a second circuit member 5 is further arranged on the circuit-connecting adhesive film 1 arranged 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 arranged opposite each other, with the circuit-connecting adhesive film 1 interposed between the first circuit member 4 and the second circuit member 5). When the circuit-connecting adhesive film 1 is laminated on a substrate (not shown), the substrate is removed and the second circuit member 5 is arranged on the circuit-connecting adhesive film 1.

[0194] Then, the circuit connection adhesive film 1 is Figure 4 (c) The circuit connection adhesive film 1 is cured by heat pressing in the direction of arrows A and B. The first electrode 42 and the second electrode 52 are electrically connected to each other. As a result, a circuit connection adhesive film 1 is obtained. Figure 3 The structure 10 is shown.

[0195] In the structure 10 obtained as described above, the conductive particles 3 can be brought into contact with both the first electrode 42 and the second electrode 52 facing each other, and the connection resistance between the first electrode 42 and the second electrode 52 can be sufficiently reduced.

[0196] By heating and pressurizing the circuit-connecting adhesive film 1, the adhesive component 2 cures to form the insulating material 7 while the distance between the first electrode 42 and the second electrode 52 is sufficiently reduced, thereby firmly connecting the first circuit component 4 and the second circuit component 5 via the connecting portion 6. Furthermore, in the structure 10, sufficiently high bonding strength is maintained over a long period of time. Therefore, in the structure 10, the time-dependent change in the distance between the first electrode 42 and the second electrode 52 is substantially suppressed, resulting in excellent long-term reliability of the electrical characteristics between the first electrode 42 and the second electrode 52.

[0197] Example

[0198] Hereinafter, the present invention will be described in detail based on examples. However, the present invention is not limited to the following examples.

[0199] <Preparation of Curing Agent>

[0200] [Synthesis and Analysis of Curing Agent B1]

[0201] 100 mL of acetonitrile and a stirrer were placed in a 300 mL conical flask and placed 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 2,4,6-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 conical flask and reacted at room temperature (25°C) for 24 hours to obtain crystals. The obtained crystals were filtered with a glass filter, and after the crystals on the glass filter were washed with acetone and distilled water, vacuum dried to obtain 29.1 g of 2-cyanopyridine-1-(2,4,6-trimethylbenzyl)pyridinium iodide (yield 80%).

[0202] 200 mL of dichloromethane and a stirrer were placed in a 500 mL conical flask and placed on a magnetic stirrer. 3.6 g (10 mmol) of the obtained 2-cyano-1-(2,4,6-trimethylbenzyl)pyridinium iodide was added to a 500 mL conical flask and suspended in the dichloromethane in the 500 mL conical flask. 72 g (10.2 mmol, manufactured by Nippon Shokubai Co., Ltd.) of a sodium tetrakis(pentafluorophenyl)borate aqueous solution (solid content 10%) and 50 mL of distilled water were added to a 500 mL conical flask and stirred at room temperature (25°C) for 3 hours to perform a salt exchange reaction. After stirring, the organic layer was washed with distilled water, concentrated, and vacuum-dried to obtain 8.0 g of compound (yield 88%). The obtained compound was set as curing agent B1.

[0203] The obtained compound was analyzed by nuclear magnetic resonance spectroscopy ( 1 H-NMR, manufactured by JEOL Ltd., JNM-ECX400II) was used to measure the spectrum. 1 H-NMR measurement confirmed that the obtained compound was 2-cyano-1-(2,4,6-trimethylbenzyl)pyridinium tetrakis(pentafluorophenyl)borate having the following structure.

[0204] 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)

[0205]

[0206] <Synthesis of Phenoxy Resin a>

[0207] In a 3000mL three-necked flask equipped with a Dai's cooling tube, a calcium chloride tube, and a PTFE (registered trademark) stirring rod connected to a stirring motor, 45g of 4,4'-(9-fluorenyl)-diphenol (manufactured by Sigma-Aldrich Japan) and 50g of 3,3',5,5'-tetramethylbiphenol diglycidyl ether (product name: YX-4000H, manufactured by Mitsubishi Chemical Corporation) were dissolved in 1000mL of N-methylpyrrolidone as a reaction solution. 21g of potassium carbonate was added to the reaction solution, and the mixture was heated to 110°C with a mantle heater while stirring for 3 hours. The stirred reaction solution was added dropwise to a beaker containing 1000mL of methanol, and the precipitate generated by suction filtration was filtered out. The filtered precipitate was further washed three times with 300mL of methanol to obtain 75g of phenoxy resin a. The molecular weight of the obtained phenoxy resin a was measured using high-performance liquid chromatography (GP8020 manufactured by TOSOH CORPORATION, columns: Gelpack GL-A150S and GLA160S manufactured by Showa Denko Materials Co., Ltd., eluent: tetrahydrofuran, flow rate: 1.0 mL / min). The results were Mn = 15769, Mw = 38045, and Mw / Mn = 2.413 in terms of polystyrene.

[0208] <Production of Conductive Particles>

[0209] A layer made of nickel was formed on the surface of the cross-linked polystyrene particles so as to have a thickness of 0.15 μm, thereby obtaining conductive particles having an average particle diameter of 3.0 μm.

[0210] <Production of Adhesive Film for Circuit Connection>

[0211] A first adhesive composition for forming the first adhesive layer and a second adhesive composition for forming the second adhesive layer were prepared by mixing the components in the proportions (parts by mass) shown in Table 1. Details of the components in Table 1 are as follows. The proportions of each component in the table represent the proportions of the non-volatile component.

[0212] Cationic polymerizable compounds

[0213] A1: Bisphenol A epoxy resin (bifunctional epoxy resin, manufactured by Mitsubishi Chemical Corporation, product name: YL980)

[0214] A2: Naphthalene-type epoxy resin (quadrifunctional epoxy resin, manufactured by DIC Corporation, product name: HP4700)

[0215] A3: Trisphenol methane type epoxy resin (multifunctional epoxy resin, manufactured by Mitsubishi Chemical Corporation, product name: jER1032H60)

[0216] A4: Bisphenol A type epoxy resin (a tetrafunctional epoxy resin having two glycidyl groups and two glycidyloxy groups, manufactured by Showa Denko KK, product name: BATG)

[0217] Curing agent

[0218] B1: Curing agent synthesized above

[0219] B2: Sulfonium salt (manufactured by SANSHIN CHEMICAL INDUSTRY CO., LTD., product name: MS10)

[0220] Thermoplastic resin

[0221] C1: Phenoxy resin a synthesized above

[0222] C2: Epoxy resin (manufactured by Mitsubishi Chemical Corporation, product name: jER 1010, epoxy equivalent: 3000-5000 g / eq)

[0223] Conductive particles

[0224] D: Conductive particles prepared above

[0225] Coupling agent

[0226] E: Silane coupling agent (3-glycidyloxypropyltrimethoxysilane, manufactured by Shin-Etsu Chemical Co., Ltd., product name: KBM-403)

[0227] Filling material

[0228] F1: Surface-treated silica particles (a hydrolyzate of trimethoxyoctylsilane and silica, manufactured by Evonik Industries AG, product name: AEROSIL R805, a solution diluted with an organic solvent to a non-volatile content of 10% by mass)

[0229] F2: Surface-treated silica particles (hydrolysis product of silica and bis(trimethylsilyl)amine)

[0230] 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 to the second adhesive layer to form a first adhesive layer, thereby producing a circuit-connecting adhesive film comprising the first adhesive layer, the second adhesive layer, and the substrate laminated in this order. In each of the Examples and Comparative Examples, the thickness of the first adhesive layer of the circuit-connecting adhesive film was 7 μm, and the thickness of the second adhesive layer was 7 μm.

[0231] <Fabrication of the connection structure>

[0232] As the first circuit component, a wiring pattern of AlNd (100 nm) / Mo (50 nm) / ITO (100 nm) (pattern width: 19 μm, inter-electrode gap: 5 μm) was formed on the surface of an alkali-free glass substrate (OA-11, manufactured by Nippon Electric Glass Co., Ltd.; dimensions: 38 mm × 28 mm, thickness: 0.3 mm) was prepared. As the second circuit component, an IC chip (dimensions: 0.9 mm × 20.3 mm, thickness: 0.3 mm, bump size: 70 μm × 12 μm, inter-bump gap: 12 μm, bump thickness: 8 μm) was prepared, with bump electrodes arranged in two staggered rows.

[0233] The connection structure was fabricated using each circuit connection adhesive film of each embodiment and comparative example. First, the first adhesive layer of the circuit connection adhesive film was placed on the first circuit component. A thermal compression bonding apparatus (manufactured by OHASHI SEISAKUS YO Co., Ltd.) consisting of a ceramic heater stage and a tool (8 mm × 50 mm) was used. The pressure was maintained at 60°C and 0.98 MPa (10 kgf / cm 2 ) under the conditions of 1000 nm, and heating and pressurizing for 1 second, and attaching the circuit connection adhesive film to the first circuit component. Next, the substrate on the opposite side of the circuit connection adhesive film is peeled off, and the position of the bump electrode of the first circuit component is aligned with the circuit electrode of the second circuit component. Then, using a heating tool (8mm×45mm), a PTFE sheet with a thickness of 50μm as a buffer material is separated, and the second adhesive layer of the circuit connection adhesive film is attached to the second circuit component at the mounting temperature shown in Table 2 on a base heated to 90°C and heated and pressurized at 60MPa for 5 seconds to produce a connection structure. In addition, the mounting temperature is set to the actual measured maximum temperature reached by the circuit connection adhesive film, and the pressure is set to the value calculated based on the total area of the bump electrode of the second circuit component relative to the side opposite to the first circuit component.

[0234] <Evaluation of connection resistance>

[0235] Using the produced connection structure, the connection resistance at 14 locations was measured using a four-terminal measurement method, and the average value of the connection resistance value immediately after the connection structure was produced (initial) and after the HAST test was evaluated. For the HAST test, the connection structure was set on an accelerated life test device (manufactured by HIRAYAMA Manufacturing Corporation, product name: PC-242HSR2, conditions: 110°C / 85% RH / 150 hours). For the determination of the connection resistance, a multimeter (MLR21, manufactured by ETAC) was used. The evaluation of the connection resistance was evaluated as follows: the connection resistance less than 3.5Ω was evaluated as A, the connection resistance greater than 3.5Ω and less than 5Ω was evaluated as B, the connection resistance greater than 5Ω and less than 10Ω was evaluated as C, and the connection resistance greater than 10Ω was evaluated as D. The evaluation results are shown in Table 2.

[0236] Adhesion properties of adhesive films for circuit connection

[0237] Immediately after production (initial), the circuit-connecting adhesive film was stored at 30°C and 60% RH for 168 hours and its adhesion was evaluated. Adhesion was evaluated as follows: when the circuit-connecting adhesive film was attached to a first circuit component, an A rating was assigned if the adhesive coverage of the circuit-connecting adhesive film and the first circuit component was 90% or greater; a B rating was assigned if the coverage was 70% or greater but less than 90%; a C rating was assigned if the coverage was 20% or greater but less than 70%; and a D rating was assigned if the coverage was less than 20%. The evaluation results are shown in Table 2.

[0238] [Table 1]

[0239]

[0240] [Table 2]

[0241]

[0242] As shown in Table 2, it can be confirmed that the adhesive composition contains a cationically polymerizable compound, a curing agent, and conductive particles, and includes an epoxy compound having a bisphenol structure and having a glycidyl group and a glycidyloxy group as the cationically polymerizable compound. This allows for excellent connection resistance to be achieved even after a HAST test, and excellent adhesion over a wide range of mounting temperatures from low to high temperatures (130 to 150°C).

[0243] Explanation of symbols

[0244] 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 component, 5- Second circuit component, 6- Connecting portion, 7- Insulating substance, 10- Structure, 41- First circuit substrate, 42- First electrode, 51- Second circuit substrate, 52- Second electrode.

Claims

1. An adhesive composition comprising a cationically polymerizable compound, a curing agent, and conductive particles. The cationically polymerizable compound includes an epoxy compound having a bisphenol structure and having a glycidyl group and a glycidyloxy group.

2. The adhesive composition according to claim 1, wherein The epoxy compound has 3 or more epoxy groups.

3. The adhesive composition according to claim 1, wherein The epoxy compound is a compound represented by the following formula (2A), 4. The adhesive composition according to claim 1, wherein The curing agent includes at least one of a pyridinium salt and a sulfonium salt. 5 . An adhesive film for circuit connection, comprising an adhesive layer formed from the adhesive composition according to claim 1 .

6. An adhesive film for circuit connection, comprising 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 is a layer formed of the adhesive composition according to any one of claims 1 to 4.

7. A connection structure comprising: a first circuit component having a first electrode; a second circuit component having a second electrode; and a connecting portion disposed between the first circuit component and the second circuit component and electrically connecting the first electrode and the second electrode to each other; The connecting portion includes a cured product of the circuit-connecting adhesive film according to claim 5 .

8. A method for manufacturing a connection structure, comprising the following steps: The circuit connection adhesive film according to claim 5 is interposed between a first circuit component having a first electrode and a second circuit component having a second electrode, and the first circuit component and the second circuit component are thermally compressed to electrically connect the first electrode and the second electrode to each other.

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