Adhesive composition and structure

Abstract

The invention provides an adhesive composition and a structure. The adhesive composition contains (a) a thermoplastic resin having a urethane bond, (b) a radical polymerizable compound, (c) a radical polymerization initiator, (d) polyurethane beads, and (e) non-conductive inorganic fine particles. The non-conductive inorganic fine particles are one or more selected from the group consisting of silica fine particles, alumina fine particles, silica-alumina fine particles, titania fine particles, and zirconia fine particles, and the content of the non-conductive inorganic fine particles is 5-20 mass% based on the total mass of the adhesive component. The radical-polymerizable compound contains a radical-polymerizable compound having a phosphate ester structure represented by general formula (1) (in the formula, p represents an integer of 1-3, and R represents a hydrogen atom or a methyl group.

Description

[0001] This application is a divisional application of Chinese patent application No. 201880021694.3, filed on March 28, 2018, entitled "Adhesive Composition and Structure". Technical Field

[0002] This disclosure relates to adhesive compositions and structures. Background Technology

[0003] In semiconductor components and liquid crystal display (LCD) components, various adhesives have long been used to bond the various components together. Regarding the required properties of adhesives, adhesion is paramount, but other aspects include heat resistance and reliability under high temperature and humidity conditions. Furthermore, the materials used for bonding include printed circuit boards, organic substrates (such as polyimide substrates), metals (titanium, copper, aluminum, etc.), and materials with ITO (Indium Tin Oxide), IZO (Indium Zinc Oxide), IGZO (Indium Gallium Zinc Oxide), and SiN. X For substrates with surface states such as SiO2, the molecular design of the adhesive needs to be tailored to each substrate being bonded.

[0004] Traditionally, adhesives for semiconductor components or liquid crystal display components have used thermosetting resins (epoxy resins, acrylic resins, etc.) that exhibit high adhesion and reliability. As components of adhesives using epoxy resins, epoxy resins and latent curing agents (cationic or anionic species that react with epoxy resins due to heat or light) are generally used. The latent curing agent is a crucial factor determining the curing temperature and rate; various compounds are used considering both storage stability at room temperature and curing speed upon heating. In actual processes, for example, the desired adhesion is achieved by curing at temperatures of 170–250°C for 10 seconds to 3 hours.

[0005] Furthermore, in recent years, with the increasing integration of semiconductor components and the increasing precision of liquid crystal display components, the spacing between components and wiring has become narrower, raising concerns about the adverse effects of heat during curing on surrounding components. Moreover, to reduce costs and increase production capacity, bonding needs to be performed at low temperatures (90–170°C) and for short periods (less than 1 hour, preferably less than 10 seconds, more preferably less than 5 seconds). In other words, bonding requires low-temperature, short-time curing (low-temperature rapid curing). Achieving this low-temperature, short-time curing requires the use of thermally latent catalysts with low activation energy, but it is known that achieving storage stability near room temperature is very difficult.

[0006] Therefore, in recent years, free radical curing adhesives utilizing (meth)acrylate derivatives and peroxides as free radical polymerization initiators have attracted considerable attention. Regarding free radical curing systems, since free radicals, as reactive species, are highly reactive, short-time curing can be achieved. Furthermore, because peroxides are stably present at temperatures below or equal to the decomposition temperature of the free radical polymerization initiator, these curing systems combine low-temperature short-time curing with storage stability (e.g., storage stability near room temperature). For example, free radical curing adhesive compositions as shown in Patent Documents 1-3 are known.

[0007] Existing technical documents

[0008] Patent documents

[0009] Patent Document 1: Japanese Patent Application Publication No. 2006-22231

[0010] Patent Document 2: Japanese Patent Application Publication No. 2009-1765

[0011] Patent Document 3: International Publication No. 2009 / 063827 Summary of the Invention

[0012] The problem that the invention aims to solve

[0013] In recent years, the interconnects between semiconductor components and liquid crystal display components have been further miniaturized, requiring adhesives with sufficient bonding strength even for smaller interconnect areas. However, conventional adhesives are known to fail to achieve adequate bonding strength.

[0014] Therefore, the purpose of this disclosure is to provide an adhesive composition and a structure using the adhesive composition, wherein the adhesive composition is a free radical curing adhesive capable of low-temperature short-time bonding (low-temperature short-time curing), and sufficient adhesive strength can be obtained even when the bonding area is small.

[0015] Methods for solving problems

[0016] During their research, the inventors focused on polyurethane beads. Furthermore, in their studies of adhesive compositions incorporating polyurethane beads, they discovered that the adhesive strength became particularly high, especially when using a resin containing urethane bonds as the thermoplastic resin. Moreover, they found that by combining non-conductive inorganic microparticles with polyurethane beads, the adhesive strength was further improved.

[0017] That is, one aspect of this disclosure provides an adhesive composition comprising: (a) a thermoplastic resin having urethane bonds, (b) a free radical polymerizable compound, (c) a free radical polymerization initiator, (d) polyurethane beads, and (e) non-conductive inorganic microparticles.

[0018] According to the adhesive composition of this disclosure, high adhesive strength can be obtained even when the bonding area is small. In particular, the adhesive composition of this disclosure achieves high adhesive strength even when the bonding area is small by combining (a) a thermoplastic resin having urethane bonds, (d) polyurethane beads, and (e) non-conductive inorganic microparticles. The inventors speculate the following reasons for this: The polyurethane beads are believed to have improved adhesion to the bonded material due to their flexibility and polarity, and the adhesive composition and its cured product have sufficient strength due to the non-conductive inorganic microparticles, thus achieving high adhesive strength even when the bonding area is small. Furthermore, the thermoplastic resin having urethane bonds (a) has a high affinity for the polyurethane beads (d), and by combining them, the dispersibility of the polyurethane beads (d) in the adhesive composition is significantly improved, resulting in excellent adhesive strength even when the bonding area is small.

[0019] The content of the thermoplastic resin having urethane bonds in the adhesive composition disclosed herein may be greater than or equal to the content of the polyurethane beads in (d) above, on a mass basis.

[0020] The adhesive composition disclosed herein may further contain (f) conductive particles.

[0021] The adhesive composition disclosed herein can be used for circuit connections (an adhesive composition for circuit connections).

[0022] Another aspect of this disclosure provides a structure having the adhesive composition or cured form thereof described in one aspect of this disclosure.

[0023] Another aspect of this disclosure provides a structure comprising: a first circuit member having a first circuit electrode, a second circuit member having a second circuit electrode, and a circuit connection member disposed between the first circuit member and the second circuit member, wherein the first circuit electrode and the second circuit electrode are electrically connected, and the circuit connection member comprises the adhesive composition or cured form thereof described in one aspect of this disclosure.

[0024] The effects of the invention

[0025] According to this disclosure, an adhesive composition and a structure using the adhesive composition can be provided. The adhesive composition is a free radical curing adhesive capable of low-temperature short-time bonding (low-temperature short-time curing), which can achieve high adhesion even when the bonding area is small.

[0026] According to this disclosure, it is possible to provide the use of an adhesive composition or its cured product in a structure or in its manufacture. According to this disclosure, it is possible to provide the use of an adhesive composition or its cured product in circuit connections. According to this disclosure, it is possible to provide the use of an adhesive composition or its cured product in circuit connection structures or in their manufacture. Attached Figure Description

[0027] Figure 1 This is a cross-sectional schematic diagram illustrating one embodiment of the structure of this disclosure.

[0028] Figure 2 This is a cross-sectional schematic diagram illustrating another embodiment of the structure of this disclosure. Detailed Implementation

[0029] The following describes embodiments of the present disclosure, but the present disclosure is not limited to these embodiments in any way.

[0030] In this specification, "(meth)acrylate" refers to at least one of acrylate and the corresponding methacrylate. The same applies to other similar expressions such as "(meth)acryloyl" and "(meth)acrylic acid". Unless otherwise specified, the materials exemplified below may be used alone or in combination of two or more. Regarding the content of each component in the composition, in the case of multiple substances equivalent to each component present in the composition, unless otherwise specified, it refers to the total amount of the multiple substances present in the composition. Numerical ranges indicated by "~" represent the range of minimum and maximum values, respectively, before and after the "~". "A or B" means that either A or B may be included, or both. "Room temperature" refers to 25°C.

[0031] In the numerical ranges described in this specification, the upper or lower limit of a numerical range for one stage can be replaced with the upper or lower limit of a numerical range for another stage. Furthermore, the upper or lower limit of the numerical range described in this specification can also be replaced with the values ​​shown in the embodiments.

[0032] <Adhesive Composition>

[0033] The adhesive composition of this embodiment is an adhesive composition containing (a) a thermoplastic resin having urethane bonds (hereinafter also referred to as component (a)), (b) a free radical polymerizable compound (hereinafter also referred to as component (b)), (c) a free radical polymerization initiator (hereinafter also referred to as component (c)), (d) polyurethane beads (hereinafter also referred to as component (d)), and (e) non-conductive inorganic microparticles (hereinafter also referred to as component (e)). The adhesive composition of this embodiment may further contain (f) conductive particles (hereinafter also referred to as component (f)). The adhesive composition of this embodiment can be suitably used as an adhesive composition for circuit connection. Hereinafter, each component will be described.

[0034] (Thermoplastic resin)

[0035] The thermoplastic resin (hereinafter referred to as polyurethane resin) having urethane bonds used in this embodiment can be obtained, for example, by reacting a polyol with an isocyanate component such as a diisocyanate. The weight-average molecular weight of the polyurethane resin is preferably 5,000 to 150,000, more preferably 10,000 to 80,000. If this value is greater than or equal to 5,000, there is a tendency for good film-forming properties when the adhesive composition is used in film form; furthermore, if it is less than or equal to 150,000, there is a tendency for good compatibility with other components.

[0036] Examples of polyols used in the synthesis of polyurethane resins include polyester polyols, polyether polyols, polycarbonate polyols, acrylic polyols, polyurethane polyols, and aromatic polyols (phthalic acid polyols). Specifically, examples include polyols with ethylene glycol, propylene glycol, 1,4-butanediol, 1,6-hexanediol, neopentyl glycol, and triethylene glycol as their basic backbones. These can be used individually or in combination.

[0037] Examples of diisocyanate components include aromatic diisocyanates, aliphatic diisocyanates, and alicyclic diisocyanates. Specifically, examples include 4,4'-diphenylmethane diisocyanate (MDI), toluene diisocyanate (TDI), trimethylene diisocyanate, tetramethylene diisocyanate, hexamethylene diisocyanate (HDI), and 3-isocyanate methyl-3,5,5-trimethylcyclohexyl isocyanate (IPDI). Furthermore, isocyanurate compounds (3-functional) or isocyanate dimers (uretdione) formed from the above-mentioned diisocyanate monomers can also be used as isocyanate components. Moreover, terminal isocyanate-based polyisocyanates (e.g., adduct-type polyisocyanates, biuret-type polyisocyanates, etc.) can also be used as isocyanate components. They can be used individually or in combination.

[0038] The content of polyurethane resin in the adhesive composition, based on a mass basis, is preferably greater than or equal to the content of polyurethane beads (d). When the content of polyurethane resin is greater than or equal to the content of polyurethane beads, since a relatively large amount of polyurethane resin with high affinity for polyurethane beads is present, there is a tendency to further improve the dispersibility of polyurethane beads in the adhesive composition. Furthermore, the content of polyurethane resin, based on the total mass of the adhesive components of the adhesive composition (the solid components in the adhesive composition excluding (f) conductive particles. The same applies below), is preferably 5 to 90% by mass, more preferably 6 to 80% by mass, even more preferably 8 to 70% by mass, and particularly preferably 10 to 60% by mass. If the content of polyurethane resin is greater than or equal to 5% by mass, there is a tendency to improve the dispersibility of polyurethane beads and further improve the adhesive strength; if it is less than or equal to 90% by mass, there is a tendency to improve the flowability of the adhesive composition.

[0039] The adhesive composition of this embodiment can be used with known thermoplastic resins other than polyurethane resins. Examples of thermoplastic resins other than polyurethane resins include, for example, one or more resins selected from polyimide resins, polyamide resins, phenoxy resins, poly(meth)acrylic resins, polyester resins, and polyvinyl butyral resins.

[0040] The weight-average molecular weight of such thermoplastic resin is preferably 5,000 to 400,000, more preferably 5,000 to 200,000, and even more preferably 10,000 to 150,000. If the weight-average molecular weight of such thermoplastic resin is greater than or equal to 5,000, it tends to improve the adhesive strength of the adhesive composition; if the weight-average molecular weight is less than or equal to 400,000, it exhibits good compatibility with other components and tends to suppress the decrease in the flowability of the adhesive.

[0041] As thermoplastic resins, rubber components can also be used for stress relief and improved adhesion. Examples of rubber components include, for instance, acrylic rubber, polyisoprene, polybutadiene, carboxyl-terminated polybutadiene, hydroxyl-terminated polybutadiene, 1,2-polybutadiene, carboxyl-terminated 1,2-polybutadiene, hydroxyl-terminated 1,2-polybutadiene, styrene-butadiene rubber, hydroxyl-terminated styrene-butadiene rubber, carboxylated nitrile rubber, hydroxyl-terminated poly(oxypropylene), alkoxysilyl-terminated poly(oxypropylene), poly(oxytetramethylene) glycol, polyolefin glycol, and poly-ε-caprolactone. From the viewpoint of improved adhesion, rubber components preferably have cyano or carboxyl groups as side chain groups or terminal groups, which are highly polar groups. These rubber components can be used alone or in combination of two or more.

[0042] Based on the total mass of the adhesive components in the adhesive composition, the overall content of thermoplastic resin in the adhesive composition is preferably 20 to 90% by mass, more preferably 20 to 80% by mass, and even more preferably 30 to 70% by mass. If (a) the content of thermoplastic resin is greater than or equal to 20% by mass, there is a tendency to improve the film-forming properties of the adhesive composition while improving the adhesive strength; if it is less than or equal to 90% by mass, there is a tendency to improve the flowability of the adhesive composition.

[0043] (Free radical polymeric compounds)

[0044] (b) Free radical polymerizable compounds are compounds having functional groups capable of free radical polymerization. Examples of such free radical polymerizable compounds include (meth)acrylate compounds, maleimide compounds, citraconimide resins, and nadimide resins. The term "(meth)acrylate compound" refers to a compound having a (meth)acryloyl group. Free radical polymerizable compounds can be used as monomers or oligomers, or in combination of monomers and oligomers. A single free radical polymerizable compound can be used, or two or more can be used in combination.

[0045] Specific examples of (meth)acrylate compounds include methyl (meth)acrylate, ethyl (meth)acrylate, isopropyl (meth)acrylate, isobutyl (meth)acrylate, ethylene glycol di(meth)acrylate, diethylene glycol di(meth)acrylate, trimethylolpropane tri(meth)acrylate, tetramethylolmethane tetra(meth)acrylate, 2-hydroxy-1,3-di(meth)acryloyloxypropane, 2,2-bis[4-((meth)acryloyloxymethoxy)phenyl]propane, 2,2-bis[4-((meth)acryloyloxypolyethoxy)phenyl]propane, dicyclopentenyl (meth)acrylate, tricyclodecyl (meth)acrylate, tri((meth)acryloyloxyethyl)isocyanurate, urethane (meth)acrylate, EO-modified di(meth)acrylate, and 9,9-bis[4-(2-(meth)acryloyloxyethoxy)phenyl]fluorene, etc. As a free radical polymerizable compound other than (meth)acrylate compounds, compounds such as those described in Patent Document 3 (International Publication No. 2009 / 063827) can be suitably used. A single (meth)acrylate compound can be used alone, or two or more can be used in combination.

[0046] As a free radical polymerizable compound, (meth)acrylate compounds are preferred from the viewpoint of obtaining better storage stability, and urethane (meth)acrylate compounds are more preferred. From the viewpoint of improving heat resistance, (meth)acrylate compounds preferably have at least one substituent selected from dicyclopentenyl, tricyclodecyl, and triazine rings.

[0047] Furthermore, as a free radical polymerizable compound, a free radical polymerizable compound having a phosphate ester structure as shown in the following general formula (1) is preferred, and more preferably, the above-mentioned free radical polymerizable compound, such as a (meth)acrylate compound, is combined with a free radical polymerizable compound having a phosphate ester structure as shown in formula (1). In this case, the adhesion strength to the surface of inorganic materials (metals, etc.) is improved, and therefore, for example, it is suitable for bonding circuit electrodes to each other.

[0048] [Chemistry 1]

[0049]

[0050] [In the formula, p represents an integer from 1 to 3, and R represents a hydrogen atom or a methyl group.]

[0051] Free radical polymerizable compounds having the above-described phosphate ester structure can be obtained, for example, by reacting anhydrous phosphoric acid with 2-hydroxyethyl (meth)acrylate. Specific examples of free radical polymerizable compounds having the above-described phosphate ester structure include mono(2-(meth)acryloyloxyethyl) phosphate and di(2-(meth)acryloyloxyethyl) phosphate. Free radical polymerizable compounds having the phosphate ester structure shown in formula (1) can be used alone or in combination of two or more.

[0052] From the viewpoint of obtaining superior adhesion, the content of the free radical polymerizable compound having the phosphate ester structure shown in Formula (1) is preferably 1 to 100% by mass, more preferably 1 to 50% by mass, and even more preferably 1 to 10% by mass, based on the total mass of the free radical polymerizable compound (equivalent to the total amount of the free radical polymerizable compound components, hereinafter the same). From the viewpoint of obtaining superior adhesion, the content of the free radical polymerizable compound having the phosphate ester structure shown in Formula (1) is preferably 0.01 to 50% by mass, more preferably 0.5 to 10% by mass, and even more preferably 0.5 to 5% by mass, based on the total mass of the free radical polymerizable compound and the film-forming material (components used as needed).

[0053] The aforementioned free radical polymerizable compound may contain allyl (meth)acrylate. In this case, based on the total mass of the free radical polymerizable compound and the film-forming material (as needed), the content of allyl (meth)acrylate is preferably 0.1 to 10% by mass, more preferably 0.5 to 5% by mass.

[0054] From the viewpoint of obtaining superior adhesion, the content of the free radical polymerizable compound, based on the total mass of the adhesive component in the adhesive composition, is preferably within the following ranges: The content of the free radical polymerizable compound is preferably greater than or equal to 10% by mass, more preferably greater than or equal to 20% by mass, even more preferably greater than or equal to 30% by mass, and even more preferably greater than or equal to 40% by mass. The content of the free radical polymerizable compound is preferably less than or equal to 90% by mass, more preferably less than or equal to 80% by mass, even more preferably less than or equal to 70% by mass, particularly preferably less than or equal to 60% by mass, and extremely preferably less than or equal to 50% by mass. From these viewpoints, the content of the free radical polymerizable compound is preferably 10–90% by mass, more preferably 20–80% by mass, even more preferably 30–70% by mass, particularly preferably 40–60% by mass, and extremely preferably 40–50% by mass.

[0055] (Free radical polymerization initiator)

[0056] As (c) free radical polymerization initiators, initiators that generate free radicals due to heat (heating), initiators that generate free radicals due to light, initiators that generate free radicals due to ultrasound, electromagnetic waves, etc., can be used.

[0057] Initiators that generate free radicals due to heat are compounds that decompose upon heating to produce free radicals. Examples of such compounds include peroxides (organic peroxides, etc.) and azo compounds. The free radical polymerization initiator is appropriately selected based on the target bonding temperature, bonding time, and shelf life. From the viewpoints of stability, reactivity, and compatibility, peroxides with a 1-minute half-life temperature of 90–175°C and a molecular weight of 180–1000 are preferred. The "1-minute half-life temperature" refers to the temperature at which the half-life of the peroxide is 1 minute. The "half-life" refers to the time it takes for the concentration of a compound to decrease to half its initial value at a predetermined temperature. The 1-minute half-life temperature is the value listed in the product catalog (Organic Peroxides (10th Edition, February 2015)) published by Nippon Oil Co., Ltd.

[0058] Specific examples of initiators that generate free radicals due to heat include diacyl peroxides, dicarbonates peroxides, peroxide esters, peroxide ketals, dialkyl peroxides, hydrogen peroxides, and silyl peroxides.

[0059] From the viewpoint of suppressing corrosion of electrodes (circuit electrodes, etc.), initiators containing chloride ions and organic acids at concentrations of less than or equal to 5000 ppm are preferred as free radical polymerization initiators, and initiators that produce less organic acid after thermal decomposition are more preferred. Specific examples of such initiators include ester peroxides, dialkyl peroxides, hydrogen peroxide, and silyl peroxides, and ester peroxides are more preferred from the viewpoint of obtaining high reactivity.

[0060] As a free radical polymerization initiator, for example, it is selected from 1,1,3,3-tetramethylbutyl peroxyneodecanate, di(4-tert-butylcyclohexyl) peroxydicarbonate, di(2-ethylhexyl) peroxydicarbonate, cumyl peroxyneodecanate, 1,1,3,3-tetramethylbutyl peroxyneodecanate, dilauroyl peroxide, 1-cyclohexyl-1-methylethyl peroxyneodecanate, tert-hexyl peroxyneodecanate, tert-butyl peroxyneodecanate, tert-butyl peroxynepentyl peroxy, 1,1,3,3-tetramethylbutyl peroxy-2-ethylhexanoate, 2,5- Dimethyl-2,5-di(2-ethylhexanoyl peroxide)hexane, tert-hexyl peroxide-2-ethylhexanoate, tert-butyl peroxide-2-ethylhexanoate, tert-butyl peroxide neoheptanoate, tert-pentyl peroxide-2-ethylhexanoate, di-tert-butyl peroxide hexahydrophthalic acid ester, tert-pentyl peroxide-3,5,5-trimethylhexanoate, 3-hydroxy-1,1-dimethylbutyl peroxide neodecanoate, 1,1,3,3-tetramethylbutyl peroxide-2-ethylhexanoate, tert-pentyl peroxide neodecanoate, tert-pentyl peroxide-2-ethylhexanoate, 3-methylbenzoyl 4-Methylbenzoyl peroxide, bis(3-methylbenzoyl) peroxide, dibenzoyl peroxide, bis(4-methylbenzoyl) peroxide, 2,2'-azobis(2,4-dimethylpentanonitrile), 1,1'-azobis(1-acetoxy-1-phenylethane), 2,2'-azobisisobutyronitrile, 2,2'-azobis(2-methylbutyronitrile), dimethyl-2,2'-azobisisobutyronitrile, 4,4'-azobis(4-cyanopentanoic acid), 1,1'-azobis(1-cyclohexanecarboxynitrile), tert-hexyl peroxide isopropyl monoisobutyronitrile One or more compounds selected from carbonates, tert-butyl maleic peroxide, tert-butyl peroxide-3,5,5-trimethylhexanoate, tert-butyl peroxylaurate, 2,5-dimethyl-2,5-di(3-methylbenzoyl peroxide)hexane, tert-butyl peroxide-2-ethylhexyl monocarbonate, tert-hexyl peroxide benzoate, 2,5-dimethyl-2,5-di(benzoyl peroxide)hexane, tert-butyl peroxide benzoate, dibutyl peroxide-trimethyl adipate, tert-pentyl peroxide-octanoate, tert-pentyl peroxide-isonononate, and tert-pentyl peroxide benzoate.

[0061] Initiators that generate free radicals by light are compounds that decompose upon exposure to light to produce free radicals. Compounds that generate free radicals by exposure to light with wavelengths of 150–750 nm are suitable initiators. For example, from the viewpoint of high sensitivity to light irradiation, α-acetaminophenone derivatives and phosphine oxide derivatives described in *Photoinitiation, Photopolymerization, and Photocuring*, J.-P. Fouassier, Hanser Publishers (1995), pp. 17–35 are preferred.

[0062] Free radical polymerization initiators can be used alone or in combination of two or more. Initiators can be used in combination with decomposition accelerators, decomposition inhibitors, etc. Furthermore, initiators can be microencapsulated by coating them with polyurethane-based or polyester-based polymers. Microencapsulated initiators are preferred because they have a longer shelf life.

[0063] The content of the free radical polymerization initiator is preferably 1 to 15 parts by mass relative to the total amount of components (a) and (b) 100 parts by mass, more preferably 2.5 to 10 parts by mass.

[0064] (Polyurethane beads)

[0065] The polyurethane beads used in this embodiment are spherical organic microparticles formed from cross-linked urethane resin.

[0066] Polyurethane beads can be synthesized by reacting polyol and isocyanate components. The polyols used are primarily difunctional, but trifunctional or higher polyols can also be used in combination. Using trifunctional or higher polyols in combination can increase the crosslinking degree of the polyurethane beads.

[0067] Examples of polyol components include polyester polyols, polyether polyols, polycarbonate polyols, acrylic polyols, polyurethane polyols, and aromatic polyols (phthalic acid polyols). Among these, polycarbonate polyols or aromatic polyols are preferred for improving hydrolysis resistance. Furthermore, multifunctional polyols are preferred for improving the crosslinking degree of polyurethane beads and thus enhancing elastic recovery. Examples of multifunctional polyols include trifunctional polycaprolactone polyols. The higher the weight-average molecular weight of the multifunctional polyol, the higher its flexibility. They can be used alone or in combination.

[0068] The isocyanate component can be any of the following: yellowing type, non-yellowing type, or non-yellowing type. Examples of isocyanate components include aromatic diisocyanates, aliphatic diisocyanates, and alicyclic diisocyanates. Specifically, examples include 4,4'-diphenylmethane diisocyanate (MDI), toluene diisocyanate (TDI), trimethylene diisocyanate, tetramethylene diisocyanate, hexamethylene diisocyanate (HDI), and 3-isocyanate methyl-3,5,5-trimethylcyclohexyl isocyanate (IPDI). Furthermore, isocyanurate compounds (3-functional) or isocyanate dimers (2-functional) formed from the above-mentioned diisocyanate monomers can also be used as isocyanate components. Further, terminal isocyanate-based polyisocyanates (e.g., adduct-type polyisocyanates, biuret-type polyisocyanates, etc.) can also be used as isocyanate components. They can be used alone or in combination.

[0069] The average particle size of the polyurethane beads is not particularly limited, but is preferably 50 nm to 10 μm, more preferably 70 nm to 6 μm, and even more preferably 70 nm to 5 μm. Sometimes it is technically difficult to produce polyurethane beads smaller than 50 nm, so from the viewpoint of availability, beads larger than or equal to 50 nm are preferred. Furthermore, with a particle size smaller than or equal to 10 μm, aggregation is less likely to occur when combined with other adhesive compositions, and even if aggregation does occur, the tendency to deteriorate filterability can be suppressed. The average particle size can be confirmed, for example, by SEM.

[0070] The content of polyurethane beads is preferably less than the content of polyurethane resin as component (a). Based on this, the content is preferably 3 to 50% by mass, more preferably 4 to 40% by mass, further preferably 5 to 30% by mass, and particularly preferably 8 to 25% by mass, based on the total mass of the adhesive components in the adhesive composition. When the content is greater than or equal to 3% by mass, there is a tendency to easily obtain sufficient adhesive strength; when it is less than or equal to 50% by mass, there is a tendency to suppress the reduction of adhesive flowability.

[0071] (Non-conductive inorganic particles)

[0072] As the non-conductive inorganic particles in component (e), known non-conductive inorganic particles can be used without particular limitation. Examples of non-conductive inorganic particles include, for instance, non-conductive inorganic particles such as silica particles, alumina particles, silica-alumina particles, titanium dioxide particles, zirconium oxide particles, and other metal oxide particles. One type can be used alone, or two or more types can be used in combination. Furthermore, in this embodiment, the non-conductive inorganic particles in component (e) are not conductive and are not considered conductive particles in component (f) described later.

[0073] The average particle size of the non-conductive inorganic microparticles is preferably less than 1 μm, more preferably 0.1 to 0.5 μm. Furthermore, the average particle size referred to here is the most frequent particle size along the long axis when present in the circuit connection material. Additionally, the average first-order particle size of component (e) is preferably less than or equal to 100 nm, more preferably 10 to 30 nm. Furthermore, in this specification, the average particle size and average first-order particle size are displayed as values ​​obtained through image analysis.

[0074] As non-conductive inorganic particles, these particles exhibit excellent dispersibility, making it suitable for use when their surfaces are modified with organic groups. Examples of such organic groups include dimethylsiloxane and diphenylsiloxane.

[0075] Based on the total mass of the adhesive components, the content of non-conductive inorganic microparticles is preferably 1 to 30% by mass, more preferably 2 to 25% by mass, and even more preferably 5 to 20% by mass. If the content of component (e) is within the above range, the effects of this disclosure can be further significantly enhanced.

[0076] (Conductive particles)

[0077] The adhesive composition of this embodiment may further contain (f) conductive particles. Examples of materials constituting the conductive particles include metals such as gold (Au), silver (Ag), nickel (Ni), copper (Cu), and solder, as well as carbon. Alternatively, a non-conductive resin, glass, ceramic, or plastic may be used as a core, onto which the aforementioned metal (metal particles, etc.) or carbon-coated conductive particles are deposited. Since the coated conductive particles or hot-melt metal particles are deformable due to heating and pressure, uneven height of the circuit electrodes is eliminated during connection, increasing the contact area with the electrodes and thus improving reliability; therefore, this is preferred.

[0078] From the viewpoint of excellent dispersibility and conductivity, the average particle size of the conductive particles is preferably 1 to 30 μm, more preferably 2 to 25 μm, and even more preferably 3 to 20 μm. The average particle size of the conductive particles can be determined, for example, using equipment such as laser diffraction.

[0079] From the viewpoint of excellent conductivity, the content of conductive particles is preferably greater than or equal to 0.1 parts by volume relative to 100 parts by volume of the total volume of the adhesive component in the adhesive composition, more preferably greater than or equal to 1 part by volume. From the viewpoint of easily suppressing short circuits of electrodes (circuit electrodes, etc.), the content of conductive particles is preferably less than or equal to 50 parts by volume, more preferably less than or equal to 20 parts by volume, further preferably less than or equal to 10 parts by volume, particularly preferably less than or equal to 5 parts by volume, and extremely preferably less than or equal to 3 parts by volume, based on the total volume of the adhesive component in the adhesive composition. From these viewpoints, the content of conductive particles is preferably 0.1 to 50 parts by volume, more preferably 0.1 to 20 parts by volume, further preferably 1 to 20 parts by volume, particularly preferably 1 to 10 parts by volume, extremely preferably 1 to 5 parts by volume, and very preferably 1 to 3 parts by volume. In addition, "parts by volume" is determined based on the volume of each component before curing at 23°C, and the volume of each component can be converted from mass to volume using specific gravity. In addition, the target component can be placed into a container such as a graduated cylinder containing a suitable solvent (water, alcohol, etc.) that does not dissolve or swell the target component but fully wets it, and the increased volume can be calculated as the volume of the target component.

[0080] (Silane coupling agent)

[0081] The adhesive composition described in this embodiment may also contain a silane coupling agent. The silane coupling agent is preferably a compound represented by the following formula (2).

[0082] [Chemistry 2]

[0083]

[0084] In equation (2), R 1 R 2 and R 3 Each can independently represent a hydrogen atom, an alkyl group having 1 to 5 carbon atoms, an alkoxy group having 1 to 5 carbon atoms, an alkoxycarbonyl group having 1 to 5 carbon atoms, or an aryl group. R 1 R 2 and R 3 At least one of them is an alkoxy group. R 4 The group represents (meth)acryloyl, (meth)acryloyloxy, vinyl, isocyanate, imidazole, mercapto, amino group that can be substituted with aminoalkyl, methylamino, dimethylamino, benzylamino, phenylamino, cyclohexylamino, morpholino, piperazine, ureo, glycidyl, or epoxypropoxy. 'a' represents an integer from 0 to 10.

[0085] Examples of silane coupling agents of formula (2) include, for example, vinyltrimethoxysilane, vinyltriethoxysilane, 3-epoxypropoxypropyltrimethoxysilane, 3-epoxypropoxypropylmethyldiethoxysilane, 3-(meth)acryloyloxypropylmethyldiethoxysilane, 3-(meth)acryloyloxypropyltrimethoxysilane, 3-(meth)acryloyloxypropylmethyldiethoxysilane, 3-(meth)acryloyloxypropyltriethoxysilane, N-2-(aminoethyl)-3-aminopropylmethyldiethoxysilane, N-phenyl-3-aminopropyltrimethoxysilane, 3-ureapropyltriethoxysilane, 3-mercaptopropyltrimethoxysilane, and 3-isocyanatepropyltriethoxysilane.

[0086] The content of the silane coupling agent relative to 100 parts by mass of the total amount of components (a) and (b) is preferably 0.1 to 10 parts by mass, more preferably 0.25 to 5 parts by mass. If the content of the silane coupling agent is greater than or equal to 0.1 parts by mass, the effect of suppressing interfacial delamination between circuit components and circuit connection materials and suppressing bubble generation tends to be greater. If the content of the silane coupling agent is less than or equal to 10 parts by mass, the shelf life of the adhesive composition tends to be longer.

[0087] (Other ingredients)

[0088] The adhesive composition of this embodiment may contain appropriate polymerization inhibitors such as hydroquinone and methyl ether hydroquinone as needed.

[0089] The adhesive composition of this embodiment may further contain a homopolymer or copolymer obtained by polymerizing at least one monomer component selected from the group consisting of (meth)acrylic acid, (meth)acrylate, and acrylonitrile. From the viewpoint of excellent stress relief, the adhesive composition of this embodiment preferably contains acrylic rubber, etc., as a copolymer obtained by polymerizing glycidyl acrylate having glycidyl ether groups. From the viewpoint of improving the cohesiveness of the adhesive composition, the weight-average molecular weight of the aforementioned acrylic rubber is preferably greater than or equal to 200,000.

[0090] The adhesive composition of this embodiment may also contain coated microparticles obtained by coating the surface of the conductive particles with a polymer resin or the like. When such coated microparticles are used in conjunction with the conductive particles, even with an increased content of conductive particles, short circuits caused by contact between conductive particles are easily suppressed, thus improving the insulation between adjacent circuit electrodes. The coated microparticles may be used alone without conductive particles, or they may be used in conjunction with conductive particles. Furthermore, when the adhesive composition contains coated microparticles, the term "adhesive component of the adhesive composition" in this specification refers to the solid components in the adhesive composition other than the conductive particles and coated microparticles.

[0091] The adhesive composition of this embodiment may also contain rubber microparticles, fillers, softeners, accelerators, antioxidants, colorants, flame retardants, thixotropic agents, etc. Furthermore, the adhesive composition of this embodiment may appropriately contain additives such as thickeners, leveling agents, and weather-resistant improvers.

[0092] The rubber microparticles are preferably those having an average particle size less than or equal to twice the average particle size of the conductive particles, and a storage modulus of elasticity at room temperature less than or equal to half the storage modulus of elasticity of the conductive particles and the adhesive composition at room temperature. Particularly when the rubber microparticles are made of silicone, acrylic emulsion, SBR (Styrene-Butadiene Rubber), NBR (Nitrile-Butadiene Rubber), or polybutadiene rubber, it is suitable to use two or more types of rubber microparticles alone or in combination. The three-dimensionally cross-linked rubber microparticles exhibit excellent solvent resistance and are easily dispersed in the adhesive composition.

[0093] Fillers can improve the electrical characteristics (connection reliability, etc.) between circuit electrodes. As fillers, particles with an average particle size less than or equal to half the average particle size of conductive particles can be suitably used. When using non-conductive particles with a filler, particles with an average particle size less than or equal to the average particle size of non-conductive particles can be used as fillers. Based on the total amount of adhesive components in the adhesive composition, the filler content is preferably 0.1% to 60% by mass. A content of less than or equal to 60% by mass tends to further adequately improve the connection reliability. A content of greater than or equal to 0.1% by mass tends to adequately achieve the effect of filler addition.

[0094] When the adhesive composition of this embodiment is liquid at room temperature, it can be used as a paste. When the adhesive composition is solid at room temperature, it can be used by heating or by using a solvent to paste it. There are no particular limitations on the solvent that can be used, as long as it is non-reactive to the components in the adhesive composition and exhibits sufficient solubility. The solvent is preferably a solvent with a boiling point of 50 to 150°C at normal pressure. If the boiling point is greater than or equal to 50°C, the solvent has low volatility at room temperature, so it can be used even in open systems. If the boiling point is less than or equal to 150°C, the solvent evaporates easily, thus achieving good reliability after bonding.

[0095] The adhesive composition of this embodiment can be in film form. An adhesive composition containing solvents, etc., can be applied to, for example, a fluoropolymer film, a polyethylene terephthalate film, or a release liner (release paper, etc.), and then the solvents, etc., can be removed to obtain a film-like adhesive composition. Furthermore, the above solution can be impregnated into a substrate such as a nonwoven fabric, placed on a release liner, and then the solvents, etc., can be removed to obtain a film-like adhesive composition. Using the adhesive composition in film form offers excellent operability and other advantages.

[0096] The adhesive composition of this embodiment can be bonded by applying pressure while heating or irradiating with light. By using both heating and light irradiation, bonding can be further achieved at a low temperature and for a short time. Irradiation is preferably performed using light in the wavelength range of 150–750 nm. The light source can be a low-pressure mercury lamp, a medium-pressure mercury lamp, a high-pressure mercury lamp (such as an ultra-high-pressure mercury lamp), a xenon lamp, or a metal halide lamp. The irradiation dose can be 0.1–10 J / cm². 2 There are no particular limitations on the heating temperature, but it is preferably between 50 and 170°C. There are no particular limitations on the pressure, as long as it does not damage the materials being bonded, but it is preferably between 0.1 and 10 MPa. Heating and pressurization are preferably carried out within the range of 0.5 seconds to 3 hours.

[0097] The adhesive composition of this embodiment can be used as an adhesive for the same type of substrates, or as an adhesive for different types of substrates with different coefficients of thermal expansion. Specifically, it can be used as circuit connection materials represented by anisotropic conductive adhesives, silver paste, silver film, etc.; and as semiconductor element adhesive materials represented by elastomers for CSP (Chip Size Package), underfill materials for CSP, LOC (Lead on Chip) tape, etc.

[0098] <Structures and their Manufacturing Methods>

[0099] The structure of this embodiment includes the adhesive composition or its cured form as described in this embodiment. The structure of this embodiment is, for example, a semiconductor device such as a circuit connection structure. As one embodiment of the structure, the circuit connection structure includes: a first circuit member having a first circuit electrode, a second circuit member having a second circuit electrode, and a circuit connection member disposed between the first circuit member and the second circuit member. The first circuit member, for example, has a first substrate and a first circuit electrode disposed on the first substrate. The second circuit member, for example, has a second substrate and a second circuit electrode disposed on the second substrate. The first circuit electrode and the second circuit electrode are opposite to and electrically connected. The circuit connection member contains the adhesive composition or its cured form as described in this embodiment. The structure according to this embodiment only needs to include the adhesive composition or its cured form as described in this embodiment; alternatively, a component without circuit electrodes (such as a substrate) may be used instead of the circuit member of the circuit connection structure described above.

[0100] The manufacturing method of the structure according to this embodiment includes a step of curing the adhesive composition of this embodiment. As one aspect of the manufacturing method of the structure according to this embodiment, the manufacturing method of the circuit connection structure includes the following steps: a placement step, in which the adhesive composition of this embodiment is placed between a first circuit member having a first circuit electrode and a second circuit member having a second circuit electrode; and a heating and pressurizing step, in which the first circuit member and the second circuit member are pressurized to electrically connect the first circuit electrode and the second circuit electrode, while the adhesive composition is heated to cure it. In the placement step, the first circuit electrode and the second circuit electrode can be placed facing each other. In the heating and pressurizing step, the first circuit member and the second circuit member can be pressurized in opposing directions.

[0101] The following description uses the accompanying drawings to illustrate a circuit connection structure and its manufacturing method as one embodiment of this invention. Figure 1 This is a cross-sectional schematic diagram illustrating one embodiment of the structure. Figure 1 The circuit connection structure 100a shown includes opposing circuit members (first circuit member) 20 and circuit members (second circuit member) 30, and a circuit connection member 10 connecting them is disposed between the circuit members 20 and 30. The circuit connection member 10 contains a cured product of the adhesive composition of this embodiment.

[0102] The circuit component 20 includes a substrate (first substrate) 21 and a circuit electrode (first circuit electrode) 22 disposed on the main surface 21a of the substrate 21. An insulating layer (not shown) may be disposed on the main surface 21a of the substrate 21 as needed.

[0103] The circuit component 30 includes: a substrate (second substrate) 31 and circuit electrodes (second circuit electrodes) 32 disposed on the main surface 31a of the substrate 31. An insulating layer (not shown) may be disposed on the main surface 31a of the substrate 31 as needed.

[0104] The circuit connection component 10 contains an insulating material (a solidified product of components other than conductive particles) 10a and conductive particles 10b. The conductive particles 10b are disposed at least between opposing circuit electrodes 22 and 32. In the circuit connection structure 100a, the circuit electrodes 22 and 32 are electrically connected by means of the conductive particles 10b.

[0105] Circuit components 20 and 30 have one or more circuit electrodes (connection terminals). Circuit components 20 and 30 can be, for example, components with electrodes requiring electrical connection. As circuit components, chip components such as semiconductor chips (IC chips), resistor chips, and capacitor chips; substrates such as printed circuit boards and semiconductor mounting substrates can be used. Examples of combinations of circuit components 20 and 30 include, for example, semiconductor chips and semiconductor mounting substrates. Examples of substrate materials include, for example, inorganic materials such as semiconductors, glass, and ceramics; organic materials such as polyimide, polyethylene terephthalate, polycarbonate, (meth)acrylic resin, and cyclic olefin resins; and composites of glass and epoxy, etc. The substrate can be a plastic substrate.

[0106] Figure 2 A cross-sectional schematic diagram illustrating other embodiments of the structure. Figure 2 The circuit connection structure 100b shown has the same structure as the circuit connection structure 100a, except that the circuit connection member 10 does not contain conductive particles 10b. Figure 2 In the circuit connection structure 100b shown, circuit electrode 22 and circuit electrode 32 are in direct contact and electrically connected without the aid of conductive particles.

[0107] Circuit connection structures 100a and 100b can be manufactured, for example, by the following method. First, when the adhesive composition is in paste form, a resin layer containing the adhesive composition is disposed on the circuit member 20 by coating and drying the adhesive composition. When the adhesive composition is in film form, a resin layer containing the adhesive composition is disposed on the circuit member 20 by adhering the film-like adhesive composition to the circuit member 20. Next, the circuit member 30 is placed on the resin layer disposed on the circuit member 20 in such a way that the circuit electrode 22 and the circuit electrode 32 are arranged opposite each other. Then, the adhesive composition is cured by heat treatment or light irradiation of the resin layer containing the adhesive composition to obtain a cured product (circuit connection member 10). Through the above operations, circuit connection structures 100a and 100b can be obtained.

[0108] Example

[0109] The present disclosure will now be described in more detail by way of examples and comparative examples. However, the present disclosure is not limited to the following examples.

[0110] (Synthesis of polyurethane resin)

[0111] In a detachable flask equipped with a reflux condenser, thermometer, and stirrer, 1000 parts by mass of polypropylene glycol (manufactured by Wako Pure Chemical Industries, Ltd., number average molecular weight Mn = 2000), which is a diol with ether bonds, and 4000 parts by mass of methyl ethyl ketone (solvent) were added, and the mixture was stirred at 40°C for 30 minutes to prepare a reaction solution. The reaction solution was then heated to 70°C, and 0.0127 parts by mass of dimethyltin laurylate (catalyst) were added. Next, a solution prepared by dissolving 125 parts by mass of 4,4'-diphenylmethane diisocyanate in 125 parts by mass of methyl ethyl ketone was added dropwise to the reaction solution over 1 hour. The mixture was then stirred at the above temperature until no absorption peak (2270 cm⁻¹) originating from the isocyanate group was observed by an infrared spectrophotometer (manufactured by Nippon Spectrophotometer Co., Ltd.). -1 A methyl ethyl ketone solution of polyurethane was obtained. The solvent volume was then adjusted to achieve a solids concentration (polyurethane concentration) of 30% by mass. The weight-average molecular weight of the resulting polyurethane (polyurethane resin), determined by GPC (gel permeation chromatography), was 320,000 (converted from standard polystyrene). The GPC determination conditions are shown in Table 1.

[0112] [Table 1]

[0113]

[0114] (Synthesis of carbamate acrylates)

[0115] In a 2L four-necked flask equipped with a thermometer, stirrer, inactive gas inlet, and reflux cooler, 4000 parts by mass of polycarbonate diol (Aldrich, number average molecular weight 2000), 238 parts by mass of 2-hydroxyethyl acrylate, 0.49 parts by mass of hydroquinone monomethyl ether, and 4.9 parts by mass of a tin-based catalyst were added to prepare a reaction solution. The reaction solution was heated to 70°C, and 666 parts by mass of isophorone diisocyanate (IPDI) were added dropwise over 3 hours to allow the reaction to proceed. After the addition was complete, the reaction was continued for 15 hours. The reaction was considered complete when the NCO% (NCO content) became less than or equal to 0.2% by mass, yielding urethane acrylate. The NCO% was confirmed using an automatic potentiometric titration apparatus (trade name: AT-510, Kyoto Electronics Industry Co., Ltd.). GPC analysis showed that the weight average molecular weight of the urethane acrylate was 8500 (converted from standard polystyrene). Furthermore, the analysis performed by GPC was conducted under the same conditions as the analysis of the weight-average molecular weight of the polyurethane resins described above.

[0116] (The creation of conductive particles)

[0117] A nickel layer with a thickness of 0.2 μm is formed on the surface of polystyrene particles. Further, a gold layer with a thickness of 0.04 μm is formed on the outer side of this nickel layer. This produces conductive particles with an average particle size of 4 μm.

[0118] [Examples 1-7 and Comparative Examples 1-4]

[0119] (Preparation of film-like adhesives)

[0120] The components shown in Table 2 were mixed at the mass ratios (solid components) shown in Table 2 to obtain a mixture. The conductive particles described above were dispersed in this mixture at a ratio of 1.5 parts by volume (reference: 100 parts by volume relative to the total volume of the adhesive components in the adhesive composition) to obtain a coating liquid for forming a film-like adhesive. This coating liquid was applied to a 50 μm thick polyethylene terephthalate (PET) film using a coating apparatus. The film was dried with hot air at 70°C for 10 minutes to form a 18 μm thick film-like adhesive.

[0121] In addition, details of each component shown in Table 2 are as follows.

[0122] Polyurethane resin: Polyurethane resin synthesized as described above.

[0123] Phenoxy resin: It is used in the form of a 40% by mass solution prepared by dissolving 40g of PKHC (manufactured by Union Carbide Co., Ltd., trade name, weight average molecular weight 45000) in 60g of methyl ethyl ketone.

[0124] Free radical polymerizable compound A: using urethane acrylate synthesized as described above.

[0125] Free radical polymerizable compound B: isocyanuric acid EO-modified diacrylate (trade name: M-215, manufactured by Toa Synthetic Co., Ltd.).

[0126] Free radical polymerizable compound C (phosphate ester): 2-methacryloyloxyethyl phosphate ester (trade name: Light Ester P-2M, manufactured by Kyoei Chemical Co., Ltd.).

[0127] Peroxide (free radical polymerization initiator): 1,1,3,3-tetramethylbutylperoxide-2-ethylhexanoate (trade name: PEROCTA O, manufactured by Nippon Oil Co., Ltd., 1-minute half-life temperature: 124.3°C).

[0128] Polyurethane beads A: are used in the form of a 10% by mass solution obtained by dispersing 10g of P-800T (manufactured by Nejou Kogyo Co., Ltd., trade name, average particle size: 6μm, glass transition temperature: -34℃) in 90g of methyl ethyl ketone.

[0129] Polyurethane beads B: Used in the form of a 10% by mass solution obtained by dispersing 10g of JB-800T (manufactured by Nejou Kogyo Co., Ltd., trade name, average particle size: 6μm, glass transition temperature: -52℃) in 90g of methyl ethyl ketone.

[0130] Silica microparticles (non-conductive inorganic microparticles): Used in the form of a 10% by mass dispersion obtained by dispersing 10g of R104 (manufactured by AEROSIL Co., Ltd., Japan, trade name) in a mixed solvent of 45g toluene and 45g ethyl acetate.

[0131] (Construction of the connector)

[0132] Using the film adhesives of Examples 1-7 and Comparative Examples 1-4, a flexible circuit board (FPC) having 2200 copper circuits with a line width of 75 μm, a spacing of 150 μm (gap 75 μm) and a thickness of 18 μm was bonded to a glass substrate and a silicon nitride (SiN) film with a thickness of 0.2 μm formed on the glass substrate. x Thin-layer SiN x Substrate (0.7mm thickness) bonding. Bonding is performed using a thermoforming device (heating method: constant temperature type, manufactured by Toray Engineering Co., Ltd.), by heating and pressurizing at 170°C and 3MPa for 5 seconds. This creates a cured film of an adhesive that bonds the FPC and SiN... xThe substrate is connected to form a connector (structure) with widths of 1.5 mm and 1.0 mm. With a width of 1.5 mm, the pressing area is set to 0.495 cm². 2 To calculate the applied pressure, with a width of 1.0 mm, the pressing area is set to 0.330 cm². 2 To calculate the applied pressure.

[0133] <Determination of Bond Strength>

[0134] The adhesive strength of the resulting bond was determined using the 90-degree peel test according to JIS-Z0237. A Tensilon UTM-4 (manufactured by Toyo Baldwin Co., Ltd., trade name, peel strength 50 mm / min, 25°C) was used as the adhesive strength measuring apparatus. The results are shown in Table 2.

[0135] [Table 2]

[0136]

[0137] As can be confirmed from Table 2, the film adhesive of the embodiments, compared with the film adhesive of the comparative examples, can obtain high adhesive strength (greater than or equal to 8 N / cm) even when joined with a width of 1.0 mm. In the film adhesive of Comparative Example 1, although high adhesive strength was obtained when joined with a width of 1.5 mm, sufficient adhesive strength could not be obtained when joined with a width of 1.0 mm. In the film adhesives of Comparative Examples 2-4, sufficient adhesive strength could not be obtained even when joined with a width of 1.5 mm.

[0138] Symbol Explanation

[0139] 10…circuit connection component, 10a…insulating material, 10b…conductive particle, 20…first circuit component, 21…first substrate, 21a…main surface, 22…first circuit electrode, 30…second circuit component, 31…second substrate, 31a…main surface, 32…second circuit electrode, 100a, 100b…circuit connection structure.

Claims

1. An adhesive composition comprising: (a) Thermoplastic resins containing urethane bonds, (b) Free radical polymers, (c) Free radical polymerization initiators (d) polyurethane beads, and (e) Non-conductive inorganic particles, The non-conductive inorganic microparticles are selected from one or more of the group consisting of silica microparticles, alumina microparticles, silica-alumina microparticles, titanium dioxide microparticles, and zirconium oxide microparticles. Based on the total mass of the adhesive components, the content of the non-conductive inorganic microparticles is 5-20% by mass. The free radical polymerizable compound comprises a free radical polymerizable compound having a phosphate ester structure as shown in the following general formula (1). In the formula, p represents an integer from 1 to 3, and R represents a hydrogen atom or a methyl group.

2. The adhesive composition according to claim 1, wherein the content of (a) the thermoplastic resin having urethane bonds is greater than or equal to the content of (d) the polyurethane beads on a mass basis.

3. The adhesive composition according to claim 1 or 2, further comprising (f) conductive particles.

4. The adhesive composition according to claim 1 or 2, used for circuit connection.

5. A structure comprising the adhesive composition or cured form thereof as described in any one of claims 1 to 4.

6. A structure having: First circuit component having first circuit electrodes A second circuit component having a second circuit electrode, and A circuit connection component disposed between the first circuit component and the second circuit component. The first circuit electrode is electrically connected to the second circuit electrode. The circuit connection component comprises the adhesive composition or cured form thereof as described in any one of claims 1 to 4.

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