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

Abstract

The adhesive composition contains a cationically polymerizable compound and a curing agent, the cationically polymerizable compound contains a trifunctional or higher epoxy compound having an epoxy equivalent of more than 100 g / eq and 250 g / eq or less, the curing agent contains a pyridinium salt, the pyridinium salt has a benzyl group at the 1-position and an electron-withdrawing group at the 2-position, and the benzyl group has an electron-donating group. 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 an adhesive have been used as adhesive materials for connecting a liquid crystal display (LCD) to a liquid crystal driver integrated circuit, connecting an LCD to a tape carrier package (TCP), connecting a flexible printed circuit board (FPC) to a TCP, or connecting an FPC to a printed wiring board (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] However, from the viewpoint of practical application, it is desired that the adhesive film can be used for mounting in a wide temperature range from low temperature to high temperature.

[0008] Furthermore, in recent years, the requirements for connection reliability in mounted devices using adhesive films have continued to increase. To improve connection reliability, mounted devices are required to have HAST resistance, which means that the adhesive film is less likely to peel off and has minimal bubble generation even after harsh tests such as the HAST (Highly Accelerated Stress Test).

[0009] Therefore, one object of the present disclosure is to provide an adhesive composition that can be installed at temperatures ranging from low temperatures (e.g., 120°C) to high temperatures (e.g., 150°C), and that exhibits excellent appearance and minimal bubble generation even after HAST testing, both in low-temperature and high-temperature installation. Furthermore, another object of the present disclosure is to provide an adhesive composition, a circuit connection adhesive film, 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 disclosure includes the following [1] to

[13] .

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

[0013] The cationic polymerizable compound includes an epoxy compound having trifunctional or higher functionality and an epoxy equivalent of more than 100 g / eq and less than 250 g / eq,

[0014] The curing agent contains a pyridinium salt,

[0015] The pyridinium salt has a benzyl group at the 1-position and an electron-withdrawing group at the 2-position,

[0016] The benzyl group has an electron donating group.

[0017] [2] The adhesive composition according to [1], wherein the epoxy compound has an aromatic ring.

[0018] [3] The adhesive composition according to [1] or [2], wherein the epoxy compound is solid at room temperature.

[0019] [4] The adhesive composition according to any one of [1] to [3], wherein the cationic polymerizable compound comprises at least one selected from the group consisting of an epoxy compound having a trisphenolmethane structure, an epoxy compound having a bisphenol structure and having a glycidyl group and a glycidyloxy group, an epoxy compound having a tetravalent organic group and an aromatic ring bonded to the organic group, the aromatic ring having a substituent containing an epoxy group, and an epoxy compound having a naphthalene structure.

[0020] [5] The adhesive composition according to any one of [1] to [4], wherein the electron-withdrawing group is a cyano group or a halide group.

[0021] [6] The adhesive composition according to any one of [1] to [5], wherein the electron-donating group is an alkyl group or an alkoxy group.

[0022] [7] The adhesive composition according to any one of [1] to [6], wherein the number of the electron-donating groups of the benzyl group is 3,

[0023] The electron-donating group is an alkyl group.

[0024] [8] The adhesive composition according to any one of [1] to [7], wherein the pyridinium salt comprises a pyridinium cation and an anion,

[0025] The anion is B(C6F5)4 - .

[0026] [9] The adhesive composition according to any one of [1] to [8], further comprising conductive particles.

[0027]

[10] An adhesive film for circuit connection, comprising an adhesive layer formed from the adhesive composition according to any one of [1] to [9].

[0028]

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

[0029] 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 [9].

[0030]

[12] A connection structure comprising:

[0031] a first circuit member having a first electrode;

[0032] a second circuit member having a second electrode; and

[0033] a connecting portion disposed between the first circuit member and the second circuit member and electrically connecting the first electrode and the second electrode to each other;

[0034] The connecting portion includes a cured product of the circuit connecting adhesive film described in

[10] or

[11] .

[0035]

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

[0036] The circuit connection adhesive film described in

[10] or

[11] is interposed between a first circuit member having a first electrode and a second circuit member having a second electrode, and the first circuit member and the second circuit member are thermally pressed together to electrically connect the first electrode and the second electrode to each other.

[0037] Effects of the Invention

[0038] According to one aspect of the present disclosure, an adhesive composition is provided that can be mounted at temperatures ranging from low temperatures (e.g., 120°C) to high temperatures (e.g., 150°C), and that exhibits excellent appearance even after HAST testing, both in low-temperature and high-temperature mounting. Furthermore, according to another aspect of the present disclosure, an adhesive composition, a circuit connection adhesive film, a connection structure, and a method for manufacturing the connection structure using the adhesive composition are provided. BRIEF DESCRIPTION OF THE DRAWINGS

[0039] Figure 1 This is a schematic cross-sectional view showing one embodiment of an adhesive film for circuit connection.

[0040] Figure 2 This is a schematic cross-sectional view showing one embodiment of an adhesive film for circuit connection.

[0041] Figure 3 It is a schematic cross-sectional view showing one embodiment of a connection structure.

[0042] Figure 4 Yes Figure 3 Schematic cross-sectional view of a method for manufacturing a connection structure. DETAILED DESCRIPTION

[0043] Hereinafter, embodiments of the present invention will be described in detail. However, the present invention is not limited to the following embodiments.

[0044] 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 the resin range can be arbitrarily combined with the lower limit or upper limit of other numerical ranges. In the description of the class of the numerical range "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, for example, the description of the class "10 or more" refers to a value of 10 and above, and this is used as a reference even if the numerical values are different. Furthermore, for example, the description of the class "10 or less" refers to a value of 10 and below, and this is used as a reference even if the numerical values are different. 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 there are multiple substances corresponding to each component in the composition, 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, "epoxy group" refers to a substituent containing an epoxy group in a structure such as glycidol or glycidyloxy.

[0045] <Adhesive composition>

[0046] One embodiment of the present disclosure provides an adhesive composition comprising a cationically polymerizable compound and a curing agent. The cationically polymerizable compound comprises at least a trifunctional or higher epoxy compound having an epoxy equivalent weight of greater than 100 g / eq and less than 250 g / eq. The curing agent comprises at least a pyridinium salt 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.

[0047] (Cationically polymerizable compound)

[0048] The cationically polymerizable compound may be, for example, a compound that crosslinks by reacting with a curing agent by heating, and includes at least a trifunctional or higher epoxy compound having an epoxy equivalent weight of more than 100 g / eq and less than 250 g / eq (such an epoxy compound is also referred to as "epoxy compound X"). A trifunctional or higher epoxy compound refers to an epoxy compound having 3 or more epoxy groups. The epoxy equivalent weight is a value measured in accordance with JIS K7236.

[0049] The cationic polymerizable compound includes an epoxy compound X, which results in an excellent appearance of the adhesive composition and reduced bubble generation. The reasons for this are presumably as follows. Specifically, the epoxy compound has 3 or more epoxy groups and an epoxy equivalent weight of 250 g / eq or less, which increases the crosslinking density of the adhesive composition, improves adhesion to the substrate, and exhibits excellent appearance even after a HAST test. Furthermore, the epoxy compound has 3 or more epoxy groups and an epoxy equivalent weight exceeding 100 g / eq, which can suppress the stickiness of the film when the adhesive composition is formed into a film. This also allows bubbles that have entered between the substrate and the film to be easily expelled during film attachment, thereby suppressing bubble generation.

[0050] The number of epoxy groups contained in the epoxy compound X may be 4 or more, or 15 or less, 12 or less, 10 or less, 8 or less, 6 or less, or 4 or less.

[0051] The epoxy equivalent of the epoxy compound X may be 105 g / eq or more, 110 g / eq or more, 120 g / eq or more, 130 g / eq or more, 140 g / eq or more, or 150 g / eq or less, or 240 g / eq or less, or 230 g / eq or less, or 220 g / eq or less, or 210 g / eq or less, or 200 g / eq or less.

[0052] The epoxy compound X may be an epoxy compound having an aromatic ring. The epoxy compound X having an aromatic ring and an epoxy equivalent within a specific range provides a rigid skeleton, thereby improving appearance even after a HAST test and enabling the production of an adhesive composition with reduced bubble generation.

[0053] The epoxy compound X may be solid at room temperature (25° C.). Since the epoxy compound X is solid at room temperature and has an epoxy equivalent weight within a specific range, it is easier to achieve excellent appearance even after the HAST test and can further reduce the generation of bubbles compared to epoxy compounds that are liquid at room temperature.

[0054] The molecular weight of the epoxy compound X may be 200 or more, 250 or more, or 300 or more, or 1500 or less, 1000 or less, 900 or less, 800 or less, 700 or less, or 650 or less.

[0055] Examples of the epoxy compound X include an epoxy compound having a triphenolmethane structure (hereinafter, this epoxy compound is also referred to as "compound A"), an epoxy compound having a bisphenol structure and having a glycidyl group and a glycidyloxy group (hereinafter, this epoxy compound is also referred to as "compound B"), an epoxy compound having a tetravalent organic group and an aromatic ring bonded to the organic group and the aromatic ring having a substituent containing an epoxy group (hereinafter, this epoxy compound is also referred to as "compound C"), and an epoxy compound having a naphthalene structure (hereinafter, this epoxy compound is also referred to as "compound D").

[0056] From the viewpoint of more easily achieving an excellent appearance even after the HAST test and reducing the generation of bubbles, the compound A may be a compound represented by the following general formula (1A).

[0057]

[0058] [In formula (1A), R 11 、R 12 and R 13 Each independently represents a hydrogen atom or an organic group, R 11 、R 12 and R 13 At least one of them represents an organic group having an epoxy group, R 14 represents a hydrogen atom or an alkyl group, R 15 represents a hydrogen atom or an organic group.]

[0059] As R 11 、R 12 and R 13 Examples of the organic groups represented by R include alkyl, alkyl ether, 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, or 8 or less, 6 or less, or 4 or less. 11 、R 12 and R 13 At least one of them may be an organic group having a glycidyl group or an organic group having a glycidyloxy group. 11 、R 12 and R 13 From the perspective of achieving an excellent appearance even after the HAST test and reducing the generation of bubbles, R 11 、R 12 and R 13 Any of them may be an organic group having a glycidyl group, and any of them may be an organic group having a glycidyloxy group.

[0060] R 14In 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 an excellent appearance even after the HAST test and reducing the generation of bubbles, R 14 It may be a hydrogen atom.

[0061] As R 15 The organic group represented by R 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 an excellent appearance even after the HAST test and reducing the generation of bubbles, R 15 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 an excellent appearance even after the HAST test and reducing the generation of bubbles, R 15 The alkyl group may be a phenyl group having a glycidyloxy group.

[0062] The number of epoxy groups contained in compound A may be 15 or less, 12 or less, or 10 or less.

[0063] Specifically, compound A may be a compound represented by the following formula (2A).

[0064]

[0065] [In formula (2A), k represents an integer of 1 to 3.]

[0066] From the viewpoint of more easily achieving an excellent appearance even after the HAST test and reducing the generation of bubbles, the compound B may be a compound represented by the following general formula (1B).

[0067]

[0068] [In formula (1B), R 21 、R 22 、R 23 and R 24 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 21 、R 22 、R 23 and R 24 At least one of them represents an organic group having a glycidyl group, R 21 、R 22 、R 23 and R 24 At least one of them represents an organic group having a glycidyloxy group, R 25 and R26 Each independently represents a hydrogen atom or an organic group.]

[0069] As R 21 、R 22 、R 23 and R 24 Examples of the organic group include alkyl, alkylether, and alkenyl groups. These organic groups may have a substituent. 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.

[0070] R 21 、R 22 、R 23 and R 24 From the perspective of achieving an excellent appearance even after the HAST test and reducing the generation of bubbles, R 21 and R 22 Can be different, R 21 and R 22 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 an excellent appearance even after the HAST test and reducing the generation of bubbles, R 23 and R 24 Can be different, R 23 and R 24 One of them may be an organic group having a glycidyl group, and the other may be an organic group having a glycidyloxy group.

[0071] R 25 and / or R 26 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 an excellent appearance even after the HAST test and reducing the generation of bubbles, R 25 and R 26 It may be a hydrogen atom, an alkyl group, or a methyl group.

[0072] The number of epoxy groups contained in compound B may be 4 or more, or 10 or less, 8 or less, 6 or less, or 4 or less.

[0073] From the viewpoint of more easily achieving an excellent appearance even after the HAST test and reducing the generation of bubbles, the compound B may be a compound having a plurality of glycidyl groups and a plurality of glycidyloxy groups.

[0074] Specifically, the compound B may be a compound represented by the following formula (2B).

[0075]

[0076] From the viewpoint that it is easier to achieve excellent appearance even after the HAST test and the viewpoint that the generation of bubbles becomes less, compound C can be a tetravalent organic group with four aromatic rings bonded thereto, or four aromatic rings can each have an epoxy group. At this time, the four aromatic rings can be different, and from the viewpoint that it is easier to achieve excellent appearance even after the HAST test and the viewpoint that the generation of bubbles becomes less, they can also be the same. Compound C, for example, can be the following compound represented by general formula (1C).

[0077]

[0078] [In formula (1C), R 31 represents a tetravalent organic group, R 32 represents an organic group having an epoxy group.]

[0079] As R 31 The organic group represented by , for example, can be an alkyl group, an alkyl ether group, and an alkenyl group. These organic groups may have a substituent. The number of carbon atoms in the organic group may be, for example, 2 or more or 3 or more, or 8 or less, 6 or less, 4 or less, or 3 or less. From the perspective of achieving an excellent appearance even after the HAST test and reducing the generation of bubbles, R 31 It may be an alkyl group or an ethyl group.

[0080] R 32 It can be an organic group having a glycidyl group or an organic group having a glycidyloxy group. From the perspective of achieving an excellent appearance even after the HAST test and reducing the generation of bubbles, R 32 It may be an organic group having a glycidyloxy group.

[0081] The number of epoxy groups possessed by compound C may be 4 or more, or 10 or less, 8 or less, 6 or less, or 4 or less.

[0082] Specifically, the compound C may be a compound represented by the following formula (2C).

[0083]

[0084] From the viewpoint of more easily achieving an excellent appearance even after the HAST test and reducing the generation of bubbles, the compound D may be a compound represented by the following general formula (1D).

[0085]

[0086] [In formula (1), X 41 represents an oxygen atom, a sulfur atom or an alkylene group having 1 to 10 carbon atoms, R 42 and R 43 Each independently represents a glycidyl group or a glycidyloxy group, m and n each independently represent an integer of 1 to 7, and m+n is 3 or more.]

[0087] X 41 It may have a substituent. 41 In the case of an alkylene group, the carbon number of the alkylene group may be 8 or less, 6 or less, 4 or less, 3 or less, or 2 or less, from the viewpoint of achieving an excellent appearance even after the HAST test and reducing the generation of bubbles. From the viewpoint of achieving an excellent connection resistance even after the HAST test and reducing the generation of bubbles, X 41 It may be ethylene.

[0088] The compound C may be a compound represented by the following formula (2D) from the viewpoint of more easily achieving an excellent appearance even after the HAST test and from the viewpoint of reducing the generation of bubbles.

[0089]

[0090] [In formula (2D), R 44 、R 45 、R 46 and R 47 Each independently represents a hydrogen atom, a glycidyl group or a glycidyloxy group, R 44 、R 45 、R 46 and R 47 Three or more of them are glycidyl groups or glycidyloxy groups.]

[0091] In formula (2D), from the viewpoint of achieving an excellent appearance even after the HAST test and reducing the generation of bubbles, R 44 、R 45 、R 46 and R 47 They may all be glycidyl groups or glycidyloxy groups.

[0092] The cationically polymerizable compound may be composed solely of any one of Compounds A to D, or may be composed of two or more of Compounds A to D. The cationically polymerizable compound may include at least one selected from the group consisting of an epoxy compound having a trisphenolmethane structure, an epoxy compound having a bisphenol structure and having a glycidyl group and a glycidyloxy group, an epoxy compound having a tetravalent organic group and an aromatic ring bonded to the organic group, the aromatic ring having a substituent including an epoxy group, and an epoxy compound having a naphthalene structure.

[0093] The cationically polymerizable compound may contain compounds A to D and cationically polymerizable compounds other than compounds A to D. Examples of cationically polymerizable compounds other than compounds A to D include epoxy compounds (excluding compounds A to D), vinyl ether compounds, and oxetane compounds.

[0094] Examples of the epoxy compound (excluding compounds A to D) 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.

[0095] The cationically polymerizable compound may contain a bifunctional or less epoxy compound (hereinafter, such epoxy compound is also referred to as "epoxy compound Y") together with the epoxy compound X. By containing the epoxy compound X and the epoxy compound Y together with the cationically polymerizable compound, the crosslinking density can be adjusted.

[0096] The epoxy equivalent of the epoxy compound Y may be 100 g / eq or more, more than 100 g / eq, 110 g / eq or more, 120 g / eq or more, 140 g / eq or more, or 160 g / eq or less, or 300 g / eq or less, or 250 g / eq or less, or 220 g / eq or less, or 200 g / eq or less.

[0097] The ratio of the content of epoxy compound Y to the content of epoxy compound X (content of epoxy compound Y / content of epoxy compound X) may be 0.1 or more, 0.2 or more, 0.5 or more, or 0.8 or less, or 10 or less, 8 or less, 6 or less, 4 or less, 2 or less, or 1.5 or less.

[0098] As oxetane compound, as long as it is the compound with more than 1 oxetane ring structure in molecule, then 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 include epoxy compound (wherein, except compound X) and oxetane compound together with compound X.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 X) and oxetane compound. Regarding the case where only one of an epoxy compound (except compound X) and an oxetane compound is contained, the following cases can be mentioned: as a cationically polymerizable compound, one selected from epoxy compounds and oxetane compounds other than compound X is used alone together with compound X; and one selected from epoxy compounds and oxetane compounds other than compound X and a cationically polymerizable compound such as a vinyl ether compound are used in combination with compound X.

[0099] Examples of the oxetane compound include xylylenebisoxetane, 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-oxetane-1)methoxymethyl]biphenyl and 3-ethyl-3{[(3-ethyloxetane-3-yl)methoxy]methyl}oxetane, etc.

[0100] 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.

[0101] From the perspective of achieving an excellent appearance even after the HAST test and reducing the generation of bubbles, the content of the epoxy compound (including compounds A to D) in the cationically polymerizable compound can 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 cationically polymerizable compound. The content of the epoxy compound (including compounds A to D) in the cationically polymerizable compound can be substantially 100% by mass (in an embodiment where the cationically polymerizable compound is formed from the epoxy compound (including compounds A to D)).

[0102] From the perspective of achieving an excellent appearance even after the HAST test and reducing the generation of bubbles, the total content of the epoxy compound X in the cationically polymerizable compound may be 10% by mass or more, 20% by mass or more, 30% by mass or more, or 40% by mass or more, based on the total mass of the cationically polymerizable compound. The total content of the epoxy compound X in the cationically polymerizable compound may be 90% by mass or less, 80% by mass or less, 70% by mass or less, or 60% by mass or less, based on the total mass of the cationically polymerizable compound.

[0103] From the perspective of achieving an excellent appearance even after the HAST test and reducing the generation of bubbles, the total content of compounds A to D in the cationically polymerizable compound may be 10% by mass or more, 20% by mass or more, 30% by mass or more, or 40% by mass or more, based on the total mass of the cationically polymerizable compound. The total content of compounds A to D in the cationically polymerizable compound may be 90% by mass or less, 80% by mass or less, 70% by mass or less, or 60% by mass or less, based on the total mass of the cationically polymerizable compound.

[0104] (Curing Agent)

[0105] The curing agent comprises 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. The adhesive composition comprises the epoxy compound X as a cationically polymerizable compound and the pyridinium salt A as a curing agent. This allows for installation at temperatures ranging from low temperatures (e.g., 120°C) to high temperatures (e.g., 150°C). Furthermore, even after HAST testing, the adhesive composition exhibits excellent appearance and minimal bubble formation, both at low and high temperatures.

[0106] The pyridinium salt A may be, for example, a compound represented by the following general formula (3).

[0107]

[0108] [In formula (1), R 1 Represents an electron-withdrawing group, R 2 represents an electron-donating group, X - represents an anion.]

[0109] Examples of the electron-withdrawing group at the 2-position of the pyridinium salt A include cyano, halide, nitro, carbonyl, carboxyl, and sulfo groups. Examples of the halide 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 halide 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.

[0110] Examples of electron-donating groups in the benzyl group at the 1-position of the pyridinium salt A include alkyl groups, alkoxy groups, hydroxyl groups, amino groups, and alkylamino groups. Examples of alkyl groups include methyl groups, ethyl groups, n-propyl groups, and isopropyl groups. Examples of alkoxy groups include methoxy groups and ethoxy 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 an alkyl group or alkoxy group, or a methyl group or methoxy group. The benzyl ring may contain multiple electron-donating groups, and the number of electron-donating groups in the benzyl group at the 1-position of the pyridinium salt A may be 1 or more, 2 or more, or 3 or more, and may be 3. The benzyl group at the 1-position of the pyridinium salt A may 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. This is the para position relative to the bonding position of the benzyl group to the pyridine ring).

[0111] When the number of electron-donating groups possessed by the benzyl group at position 1 of the pyridinium salt A is 3, the three electron-donating groups may all be alkyl groups or may all be 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 possessed by the benzyl group at position 1 of the 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 excellent adhesion relative to circuit components and excellent peelability from the substrate of the 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 in the benzyl group at the 1-position of the pyridinium salt A being three, resulting in 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).

[0112] 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.

[0113] 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 - .

[0114] Pyridinium salt A may be a compound comprising 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.

[0115] 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 which the curing agent is substantially composed of pyridinium salt A), based on the total mass of the curing agent.

[0116] 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 an embodiment where the curing agent is substantially composed of pyridinium salt A).

[0117] A curing agent containing a pyridinium salt A can be obtained, for example, by a manufacturing method comprising the following steps: a step of reacting 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 a step of reacting the obtained pyridinium iodide and an anion salt in a solvent (e.g., dichloromethane) to obtain a pyridinium salt A.

[0118] 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.

[0119] 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.

[0120] 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.

[0121] 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.

[0122] 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.

[0123] 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 is completed, the obtained pyridinium salt A can be washed with acetone, distilled water, or the like, and then vacuum-dried to remove the solvent.

[0124] In the step of obtaining pyridinium salt A, the yield of pyridinium salt A may 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 obtainable from pyridinium iodide used to synthesize pyridinium salt A.

[0125] Regarding obtaining the pyridinium salt A, it can be obtained by using nuclear magnetic resonance spectroscopy ( 1 Specifically, it can be confirmed by the method described in the Examples described below.

[0126] 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.

[0127] 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.

[0128] 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.

[0129] 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.

[0130] (Conductive particles)

[0131] The adhesive composition may contain conductive particles. The conductive particles are not particularly limited as long as they are conductive particles. 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 having a core composed of non-conductive glass, ceramic, or plastic (polystyrene, etc.) and a coating layer comprising the above 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.

[0132] 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.

[0133] 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.

[0134] 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 .

[0135] 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.

[0136] 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.

[0137] 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.

[0138] (Thermoplastic resin)

[0139] 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.

[0140] 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.

[0141] 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, or 40% by mass or less based on the total mass of the adhesive composition.

[0142] 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.

[0143] (Coupling agent)

[0144] The adhesive composition may further contain a coupling agent. The adhesive composition contains a coupling agent, thereby further improving adhesion. The coupling agent may be a silane coupling agent, for example, 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 silane and condensates thereof. These may be used alone or in combination of two or more.

[0145] 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.

[0146] 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.

[0147] (Filling material)

[0148] 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.

[0149] 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.

[0150] 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.

[0151] 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.

[0152] 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.

[0153] 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.

[0154] 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.

[0155] Examples of the siloxane compound include tetradecamethylcycloheptasiloxane, decamethylcyclopentasiloxane, hexaphenylcyclotrisiloxane, octamethylcyclononasiloxane, hexadecylcyclooctasiloxane, dodecamethylcyclohexasiloxane, octaphenylcyclotetrasiloxane, hexamethylcyclotrisiloxane, heptaphenyldisiloxane, tetradecamethylhexasiloxane, dodecamethylpentasiloxane, hexamethyldisiloxane, decamethyltetrasiloxane, hexamethoxydisiloxane, and octamethyltrisiloxane. Alkane, 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, octaphenyloctasilsesquioxane, and the like.

[0156] 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-propyltrimethoxysilane, 3-methacryloxypropylmethyldiethoxysilane, 3-methacryloxypropyltriethoxysilane, 3-propyltrimethoxysilane, 3-methacryloxypropylmethyldimethoxysilane, 3-methacryloxypropyltrimethoxysilane, 3-methacryloxypropylmethyldiethoxysilane, 3-methacryloxypropyltriethoxysilane, 3-propyltrimethoxysilane, 3-methacryloxy ... Acryloyloxypropyltrimethoxysilane, N-2-(aminoethyl)-3-aminopropylmethyldimethoxysilane, N-2-(aminoethyl)-3-aminopropyltrimethoxysilane, 3-aminopropyltrimethoxysilane, 3-aminopropyltriethoxysilane, 3-triethoxysilyl-N-(1,3-dimethyl-butylene)propylamine, N-phenyl-3-aminopropyltrimethoxysilane, tris-(methoxysilylpropyl)isocyanuric acid, 3-ureapropyltrialkoxysilane, 3-mercaptopropylmethyldimethoxysilane, 3-mercaptopropyltrimethoxysilane, 3-isocyanatepropyltriethoxysilane, 3-trimethoxysilylpropylsuccinic anhydride, etc.

[0157] In order to further hydrophobize the hydroacidic residues on the surface of the silica particles surface treated with a silane compound or a silane coupling agent, the silica particles can be surface treated with a silane compound such as 3-methacryloxypropyltrimethoxysilane, vinyltrimethoxysilane, or trimethoxyphenylsilane to further hydrophobize the surface.

[0158] From the perspective of facilitating fluidity control when the adhesive film for circuit connection is laminated when the adhesive composition is used as an adhesive film for circuit connection, and from the perspective of improving the mechanical properties and water resistance of the connection structure after lamination, 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.

[0159] 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.

[0160] 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.

[0161] 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 in combination with monomers and oligomers. Free radical polymerizable compounds may be used alone or in combination of two or more.

[0162] 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.

[0163] 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.

[0164] 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.

[0165] 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.

[0166] 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.

[0167] 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.

[0168] 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.

[0169] 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.

[0170] Adhesive films for circuit connection

[0171] The adhesive composition may be in the form of a film. That is, another embodiment of the present disclosure is an adhesive film for circuit connection, comprising: a cationically polymerizable compound including an epoxy compound X; and a curing agent including a pyridinium salt A. The adhesive film for circuit connection may contain conductive particles.

[0172] 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 .

[0173] 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.

[0174] 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.

[0175] 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.

[0176] From the perspective of fully ensuring the curability of the circuit-connecting adhesive film, the content of the epoxy compound X in the circuit-connecting adhesive film can 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 circuit-connecting adhesive film. From the perspective of ensuring the formability of the circuit-connecting adhesive film, the content of the epoxy compound X in the circuit-connecting adhesive film can be 50% by mass or less, 40% by mass or less, 35% by mass or less, or 30% by mass or less, based on the total mass of the circuit-connecting adhesive film. From these perspectives, the content of the epoxy compound X in the circuit-connecting adhesive film can be 10 to 50% by mass, based on the total mass of the circuit-connecting adhesive film.

[0177] From the perspective of fully ensuring the curability of the adhesive film for circuit connection, the total content of compounds A to D in the adhesive film for circuit connection can 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 total content of compounds A to D in the adhesive film for circuit connection can be 50% by mass or less, 40% by mass or less, 35% by mass or less, or 30% by mass or less, based on the total mass of the adhesive film for circuit connection. From these perspectives, the total content of compounds A to D in the adhesive film for circuit connection can be 5-50% by mass or 10-50% by mass, based on the total mass of the adhesive film for circuit connection.

[0178] 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.

[0179] 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.

[0180] 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.

[0181] 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.

[0182] 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.

[0183] 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.

[0184] 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.

[0185] The circuit-connecting adhesive film may be a single layer or a multilayer structure comprising multiple laminated layers. When the circuit-connecting adhesive film has a multilayer structure, for example, the circuit-connecting adhesive film may include a first adhesive layer and a second adhesive layer other than the first adhesive layer, wherein the first adhesive layer contains: a cationically polymerizable compound including an epoxy compound X; and a curing agent including a pyridinium salt A. That is, the circuit-connecting adhesive film may include a first adhesive layer and a second adhesive layer laminated on the first adhesive layer. At least one of the first adhesive layer and the second adhesive layer may contain: a cationically polymerizable compound including an epoxy compound X; a curing agent including a pyridinium salt A; and conductive particles. When the circuit-connecting adhesive film has a multilayer structure, the content of each of the above components in each layer may be within the above-described ranges based on the total mass of each layer.

[0186] 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 can be a region containing a cationically polymerizable compound including an epoxy compound X and a curing agent including a pyridinium salt A. Specifically, the adhesive film for circuit connection can include: a first region formed from a first adhesive composition containing a cationically polymerizable compound including an epoxy compound X and a curing agent including a pyridinium salt A; and a second region disposed on the first region and formed from a second adhesive composition. When the adhesive film for circuit connection has multiple regions, the contents of the aforementioned components in each region can be within the aforementioned ranges based on the total mass of each region.

[0187] 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.

[0188] Figure 1 1 is a schematic cross-sectional view showing an embodiment of a circuit connection adhesive film. 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 cationically polymerizable compound including an epoxy compound X and a curing agent including a pyridinium salt A. The circuit-connecting adhesive film 1 may be in an uncured state or a partially cured state.

[0189] 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.

[0190] 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 circuit-connecting adhesive film 1 may have a two-layer structure comprising a layer 1A containing conductive particles 3A (a first adhesive layer formed from an adhesive component 2A and conductive particles 3A dispersed in the adhesive component 2A) and a layer 1B containing no conductive particles (a second adhesive layer formed from an adhesive component 2B). In this case, the first adhesive layer 1A may be formed from an adhesive composition (a first adhesive composition) containing a cationically polymerizable compound including an epoxy compound X, a curing agent including a pyridinium salt A, and conductive particles. The second adhesive layer 1B may be formed from an adhesive composition (a second adhesive composition) containing a cationically polymerizable compound including an epoxy compound X and a curing agent including a pyridinium salt A. The types and contents of the components contained in the second adhesive layer 1B may 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 may be in an uncured state or in a partially cured state.

[0191] 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 more, or 1.5 or less or 0.5 or less.

[0192] The circuit-connecting adhesive film may be an anisotropically conductive adhesive film (anisotropic conductive film) or a conductive adhesive film without anisotropic conductivity.

[0193] <Connection structure>

[0194] 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.

[0195] Figure 3 : is a schematic cross-sectional view showing one embodiment of a connection structure. Figure 3 As shown, the structure 10 includes a first circuit member 4 and a second circuit member 5 facing each other, and a connecting portion 6 connecting the first circuit member 4 and the second circuit member 5 .

[0196] The first circuit member 4 includes a first circuit board 41 and a first electrode 42 formed on a main 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 main surface 51a of the second circuit board 51.

[0197] The first circuit member 4 and the second circuit member 5 are not particularly limited as long as they are members having electrodes required for electrical connection. Examples of members (circuit members, etc.) having electrodes formed thereon 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.

[0198] 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.

[0199] 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 member 4 and the second circuit member 5 to be fully exerted.

[0200] <Method for Manufacturing Connected Structure>

[0201] 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.

[0202] Figure 4 Schematic cross-sectional view showing one embodiment of a method for manufacturing a connection structure. Figure 4 As shown in (a), first, prepare the first circuit member 4 and the circuit connection adhesive film 1. Next, the circuit connection adhesive film 1 is arranged on the main surface 41a of the first circuit member 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 oriented toward the first circuit member 4, and the laminate is arranged on the first circuit member 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 conductive particles is in contact with the main surface 41a of the first circuit component 4.

[0203] 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.

[0204] 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.

[0205] 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.

[0206] 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.

[0207] 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 member 4 and the second circuit member 5 via the connecting portion 6. Furthermore, in the structure 10, sufficiently high bonding strength is maintained over a long period of time. Consequently, in the structure 10, temporal changes in the distance between the first electrode 42 and the second electrode 52 are substantially suppressed, resulting in excellent long-term reliability of the electrical characteristics between the first electrode 42 and the second electrode 52.

[0208] Example

[0209] Hereinafter, the present invention will be described in detail with reference to Examples. However, the present invention is not limited to the following Examples.

[0210] <Preparation of Curing Agent>

[0211] [Synthesis and Analysis of Curing Agent B1]

[0212] 100 mL of acetonitrile and a stirrer were placed in a 300 mL Erlenmeyer 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.), and 17.8 g (119 mmol, manufactured by Tokyo Chemical Industry Co., Ltd.) of 2-cyanopyridine were added to the acetonitrile in the 300 mL Erlenmeyer flask and reacted at room temperature (25°C) for 24 hours to obtain crystals. The obtained crystals were filtered with a glass filter, washed with acetone and distilled water, and then vacuum dried to obtain 29.1 g of 2-cyano-1-(2,4,6-trimethylbenzyl)pyridinium iodide (yield 80%).

[0213] 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.

[0214] 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.

[0215] 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)

[0216]

[0217] <Synthesis of Phenoxy Resin a>

[0218] In a 3000 mL 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, 45 g of 4,4'-(9-fluorenyl)-diphenol (manufactured by Sigma-Aldrich Japan) and 50 g of 3,3',5,5'-tetramethylbiphenol diglycidyl ether (product name: YX-4000H, manufactured by Mitsubishi Chemical Corporation) were dissolved in 1000 mL of N-methylpyrrolidone as a reaction solution. 21 g of potassium carbonate was added to the reaction solution, and the mixture was stirred for 3 hours while being heated to 110°C using a mantle heater. The stirred reaction solution was added dropwise to a beaker containing 1000 mL of methanol, and the precipitate generated by suction filtration was filtered out. The filtered precipitate was further washed three times with 300 mL of methanol to obtain 75 g of phenoxy resin a. The molecular weight of the obtained phenoxy resin a was measured using 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.

[0219] <Production of Conductive Particles>

[0220] 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.

[0221] <Production of Adhesive Film for Circuit Connection>

[0222] 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, and the amounts of each component in the table represent the amount of the non-volatile component.

[0223] Cationic polymerizable compounds

[0224] A1: Bisphenol A epoxy resin (bifunctional epoxy resin, manufactured by Mitsubishi Chemical Corporation, product name: YL980, epoxy equivalent: 180-190 g / eq)

[0225] A2: Naphthalene-type epoxy resin (quadrifunctional epoxy resin, manufactured by DIC Corporation, product name: HP4700, epoxy equivalent: 165 g / eq, solid at room temperature)

[0226] A3: Trisphenol methane-type epoxy resin (multifunctional epoxy resin, manufactured by Mitsubishi Chemical Corporation, product name: jER1032H60, epoxy equivalent: 163-175 g / eq, solid at room temperature)

[0227] A4: Tetraphenolmethane-type epoxy resin (quadrifunctional epoxy resin, manufactured by Mitsubishi Chemical Corporation, product name: jER1031S, epoxy equivalent: 180-220 g / eq, solid at room temperature)

[0228] A5: Bisphenol A epoxy resin (a tetrafunctional epoxy resin having two glycidyl groups and two glycidyloxy groups, manufactured by Showa Denko KK, product name: BATG, epoxy equivalent: 120-128 g / eq, liquid at room temperature)

[0229] A6: Bisphenol F epoxy resin (bifunctional epoxy resin, manufactured by Mitsubishi Chemical Corporation, product name: YL983U, epoxy equivalent: 165-175 g / eq)

[0230] A7: Novolac-type epoxy resin with an aralkyl skeleton (trifunctional epoxy resin, manufactured by Mitsubishi Chemical Corporation, product name: YX7700, epoxy equivalent: 260-285 g / eq, solid at room temperature)

[0231] A8: Aliphatic epoxy resin (quadrifunctional epoxy resin, manufactured by Showa Denko KK, product name: PETG, epoxy equivalent: 90-100 g / eq)

[0232] Curing agent

[0233] B1: Curing agent synthesized above

[0234] B2: Sulfonium salt (manufactured by SANSHIN CHEMICAL INDUSTRY CO., LTD., product name: SI60)

[0235] Thermoplastic resin

[0236] C1: Phenoxy resin a synthesized above

[0237] C2: Epoxy resin (manufactured by Mitsubishi Chemical Corporation, product name: jER1010, epoxy equivalent: 3000-5000 g / eq)

[0238] Filling material

[0239] D1: Surface-treated silica particles (hydrolysis product of silica and bis(trimethylsilyl)amine)

[0240] D2: Surface-treated silica particles (a hydrolyzate of trimethoxyoctylsilane and silica, manufactured by Evonik Industries AG, product name: AEROSIL R805, diluted with an organic solvent to a non-volatile content of 10% by mass)

[0241] Coupling agent

[0242] E1: Silane coupling agent (3-glycidoxypropyltrimethoxysilane, product name: KBM-403, manufactured by Shin-Etsu Chemical Co., Ltd.)

[0243] Conductive particles

[0244] F1: Conductive particles produced in the above

[0245] 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 a sequential stack of the first adhesive layer, the second adhesive layer, and the substrate. 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.

[0246] <Fabrication of the connection structure>

[0247] As the first circuit component, a wiring pattern of AlNd (100 nm) / Mo (50 nm) / ITO (100 nm) (pattern width: 19 μm, inter-electrode spacing: 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 spacing: 12 μm, bump thickness: 8 μm) was prepared, with bump electrodes arranged in two staggered rows.

[0248] A connection structure was produced 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 member. A thermal compression bonding apparatus (manufactured by OHASHI SEISAKUSYO Co., Ltd.) consisting of a ceramic heater and a tool (8 mm × 50 mm) was used at 60°C and 0.98 MPa (10 kgf / cm 2 ) under the conditions of 1000 nm and 2000 nm, and heat and pressurize for 1 second, and attach the circuit connection adhesive film to the first circuit member. Then, peel off the substrate on the side opposite to the first circuit member of the circuit connection adhesive film, and align the position of the bump electrode of the first circuit member with the circuit electrode of the second circuit member. 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 member on a base heated to 90°C at the installation temperature shown in Table 2 and heated and pressurized at 60MPa for 5 seconds to produce a connection structure. In addition, the installation temperature is set to the 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 member relative to the surface opposite to the first circuit member.

[0249] <Appearance Evaluation>

[0250] Evaluation of appearance after the HAST test. The HAST test was conducted in an accelerated life testing apparatus (manufactured by HIR AYAMA Manufacturing Corporation, product name: PC-242HSR2, conditions: 110°C / 85% RH / 150 hours). The appearance was evaluated as follows: An A rating was given for a peeled area of the circuit connection adhesive film relative to the area of the bonding surface of less than 1%, a B rating for a peeled area of 1% or more and less than 10%, a C rating for a peeled area of 10% or more and less than 50%, and a D rating for a peeled area of 50% or more. The evaluation results are shown in Table 2.

[0251] <Evaluation of Bubbles>

[0252] The presence of bubbles was evaluated after the HAST test. The HAST test was conducted in an accelerated life testing apparatus (manufactured by HIRAYAMA Manufacturing Corporation, product name: PC-242HSR2, conditions: 110°C / 85% RH / 150 hours). Bubbles were evaluated as follows: if the area of the bubble-generating site relative to the bonding surface of the circuit connection adhesive film was less than 10%, the rating was A; if it was 10% or more, the rating was B. The evaluation results are shown in Table 2.

[0253]

[0254]

[0255] As shown in Table 2, it can be confirmed that the adhesive composition contains a trifunctional or higher epoxy compound with an epoxy equivalent of more than 100 g / eq and less than 250 g / eq as a cationically polymerizable compound, and contains a pyridinium salt having a benzyl group at the 1-position and an electron-withdrawing group at the 2-position, and an electron-donating group at the benzyl group as a curing agent. This allows installation at temperatures ranging from low temperatures (e.g., 120°C) to high temperatures (e.g., 150°C). In both low-temperature and high-temperature installations, the adhesive composition exhibits excellent appearance and exhibits minimal bubble generation even after the HAST test.

[0256] Explanation of symbols

[0257] 1- Adhesive film for circuit connection, 1A- First adhesive layer, 1B- Second adhesive layer, 2, 2A, 2B- Adhesive components, 3, 3A- Conductive particles, 4- First circuit member, 5- Second circuit member, 6- 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 and a curing agent, The cationic polymerizable compound includes an epoxy compound having trifunctional or higher functionality and an epoxy equivalent of more than 100 g / eq and less than 250 g / eq, The curing agent contains a pyridinium salt, The pyridinium salt has a benzyl group at the 1-position and an electron-withdrawing group at the 2-position, The benzyl group has an electron donating group.

2. The adhesive composition according to claim 1, wherein The epoxy compound has an aromatic ring.

3. The adhesive composition according to claim 1, wherein The epoxy compound is solid at room temperature.

4. The adhesive composition according to claim 1, wherein The cationic polymerizable compound includes at least one selected from the group consisting of an epoxy compound having a trisphenolmethane structure, an epoxy compound having a bisphenol structure and having a glycidyl group and a glycidyloxy group, an epoxy compound having a tetravalent organic group and an aromatic ring bonded to the organic group, the aromatic ring having a substituent including an epoxy group, and an epoxy compound having a naphthalene structure.

5. The adhesive composition according to claim 1, wherein The electron-withdrawing group is a cyano group or a halide group.

6. The adhesive composition according to claim 1, wherein The electron-donating group is an alkyl group or an alkoxy group.

7. The adhesive composition according to claim 1, wherein The number of the electron-donating groups of the benzyl group is 3, The electron-donating group is an alkyl group.

8. The adhesive composition according to claim 1, wherein The pyridinium salt comprises a pyridinium cation and an anion, The anion is B(C6F5)4 - . 9 . The adhesive composition according to claim 1 , further comprising conductive particles. 10 . An adhesive film for circuit connection, comprising an adhesive layer formed from the adhesive composition according to claim 1 .

11. 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 9.

12. A connection structure comprising: a first circuit member having a first electrode; a second circuit member having a second electrode; and a connecting portion disposed between the first circuit member and the second circuit member and electrically connecting the first electrode and the second electrode to each other; The connecting portion includes a cured product of the circuit-connecting adhesive film according to claim 10 .

13. A method for manufacturing a connection structure, comprising the following steps: The circuit-connecting adhesive film according to claim 10 is interposed between a first circuit member having a first electrode and a second circuit member having a second electrode, and the first circuit member and the second circuit member are thermocompression-bonded to electrically connect the first electrode and the second electrode to each other.

Images