JPWO2018181589A1 - Adhesive composition and structure - Google Patents

Abstract

It 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. , Adhesive composition.

Description

  The present disclosure relates to adhesive compositions and structures.

2. Description of the Related Art In semiconductor devices and liquid crystal display devices (display display devices), various adhesives have conventionally been used for the purpose of bonding various members in the devices. The properties required for the adhesive include a variety of properties such as adhesiveness, heat resistance, and reliability in a high-temperature and high-humidity state. Examples of the adherend used for bonding include a printed wiring board, an organic substrate (such as a polyimide substrate), a metal (such as titanium, copper, and aluminum), ITO (Indium Tin Oxide), and IZO (Indium Zinc Oxide). IGZO (Indium Gallium Zinc Oxide), a substrate having a surface state such as SiN _X , SiO ₂ or the like is used, and the molecular design of the adhesive is required for each adherend.

  Conventionally, thermosetting resins (epoxy resin, acrylic resin, etc.) exhibiting high adhesiveness and high reliability have been used as adhesives for semiconductor elements or liquid crystal display elements. As a component of the adhesive using the epoxy resin, an epoxy resin and a latent curing agent which generates a cationic or anionic species having reactivity with the epoxy resin by heat or light are generally used. The latent curing agent is an important factor that determines the curing temperature and the curing speed, and various compounds have been used from the viewpoint of storage stability at room temperature and the curing speed at the time of heating. In an actual process, for example, desired adhesiveness was obtained by curing under a curing condition of a temperature of 170 to 250 ° C. and a time of 10 seconds to 3 hours.

  Further, in recent years, with high integration of semiconductor elements and high definition of liquid crystal display elements, the pitch between elements and between wirings has been narrowed, and heat during curing may adversely affect peripheral members. Furthermore, in order to reduce the cost, it is necessary to improve the throughput, and the bonding at a low temperature (90 to 170 ° C.) and in a short time (within 1 hour, preferably within 10 seconds, more preferably within 5 seconds), In other words, adhesion by low-temperature short-time curing (low-temperature rapid curing) is required. In order to achieve this low-temperature and short-time curing, it is necessary to use a heat-latent catalyst having a low activation energy, but it is known that it is very difficult to combine storage stability near room temperature. .

  For this reason, in recent years, a radical-curable adhesive or the like using a (meth) acrylate derivative and a peroxide that is a radical polymerization initiator in combination has attracted attention. In the radical curing system, radicals which are reactive species are very reactive, so that curing is possible for a short time, and at a temperature lower than the decomposition temperature of the radical polymerization initiator, the peroxide is stably present. It is a curing system that achieves both low-temperature, short-time curing and storage stability (for example, storage stability near room temperature). For example, radical-curing adhesive compositions as disclosed in Patent Documents 1 to 3 below are known.

JP 2006-22231 A JP 2009-1765 A International Publication No. 2009/063827

  In recent years, the size of the connection portion between the semiconductor element and the liquid crystal display element has been further reduced, and an adhesive having sufficient adhesive strength even with a small connection area has been demanded. However, it was found that a sufficient adhesive strength could not be obtained with the conventional adhesive.

  Therefore, the present disclosure relates to a radical-curable adhesive capable of low-temperature short-time connection (low-temperature short-time curing), an adhesive composition capable of obtaining a sufficient adhesive strength even when the connection area is small, and a method of using the same. The purpose of the present invention is to provide a structure.

  The present inventors have focused on polyurethane beads during the study. The present inventors have been studying an adhesive composition containing polyurethane beads, and have found that especially when a resin containing a urethane bond is used as a thermoplastic resin, the adhesive strength is particularly increased. Was. In addition, they have found that the use of non-conductive inorganic fine particles in combination with polyurethane beads results in higher adhesive strength.

  That is, one aspect of the present disclosure relates to (a) a thermoplastic resin having a urethane bond, (b) a radical polymerizable compound, (c) a radical polymerization initiator, (d) polyurethane beads, And a conductive inorganic fine particle.

  According to the adhesive composition of the present disclosure, high adhesive strength can be obtained even when the connection area is small. In the adhesive composition of the present disclosure, particularly, the connection area is small by using a combination of (a) a thermoplastic resin having a urethane bond, (d) polyurethane beads, and (e) non-conductive inorganic fine particles. The present inventors speculate as follows about the reason why a high adhesive strength can be obtained even in such a case. That is, the adhesiveness to the adherend is improved by the flexibility and polarity of the polyurethane beads, and the adhesive composition and the cured product thereof have sufficient strength by the non-conductive inorganic fine particles, so that the connection area is small. We believe that high adhesive strength can be obtained in such cases. In addition, (a) a thermoplastic resin having a urethane bond has a high affinity for (d) polyurethane beads, and by using these in combination, dispersibility of (d) polyurethane beads in the adhesive composition is reduced. It is considered that the adhesive strength is greatly improved and excellent adhesive strength can be obtained even when the connection area is small.

  The content of the (a) thermoplastic resin having a urethane bond in the adhesive composition of the present disclosure may be not less than the content of the (d) polyurethane beads on a mass basis.

  The adhesive composition of the present disclosure may further contain (f) conductive particles.

  The adhesive composition of the present disclosure may be for circuit connection (adhesive composition for circuit connection).

  Another aspect of the present disclosure provides a structure including the adhesive composition or the cured product thereof according to the above aspect of the present disclosure.

  Another aspect of the present disclosure is a first circuit member having a first circuit electrode, a second circuit member having a second circuit electrode, and the first circuit member and the second circuit member. And a circuit connecting member disposed therebetween, wherein the first circuit electrode and the second circuit electrode are electrically connected, and the circuit connecting member is an adhesive according to one aspect of the present disclosure. A structure comprising a composition or a cured product thereof is provided.

  According to the present disclosure, in a radical-curable adhesive capable of low-temperature short-time connection (low-temperature short-time curing), an adhesive composition capable of obtaining high adhesive strength even when the connection area is small, and The structure used can be provided.

  According to the present disclosure, it is possible to provide an application of an adhesive composition or a cured product thereof to a structure or its production. According to the present disclosure, it is possible to provide an application of an adhesive composition or a cured product thereof to circuit connection. According to the present disclosure, it is possible to provide an application of an adhesive composition or a cured product thereof to a circuit connection structure or its manufacture.

1 is a schematic cross-sectional view illustrating one embodiment of a structure of the present disclosure. FIG. 6 is a schematic cross-sectional view illustrating another embodiment of the structure of the present disclosure.

  Hereinafter, embodiments of the present disclosure will be described, but the present disclosure is not limited to these embodiments.

  In the present specification, “(meth) acrylate” means at least one of acrylate and methacrylate corresponding thereto. The same applies to other similar expressions such as “(meth) acryloyl” and “(meth) acrylic acid”. The materials exemplified below may be used alone or in combination of two or more, unless otherwise specified. The content of each component in the composition means the total amount of the plurality of substances present in the composition when there are a plurality of substances corresponding to each component in the composition, unless otherwise specified. The numerical range indicated by using “to” indicates a range including the numerical values described before and after “to” as the minimum value and the maximum value, respectively. “A or B” may include one of A and B, and may include both. “Normal temperature” means 25 ° C.

  In the numerical ranges described step by step in this specification, the upper limit or the lower limit of the numerical range of a certain stage may be replaced with the upper limit or the lower limit of the numerical range of another stage. Further, in the numerical ranges described in this specification, the upper limit or the lower limit of the numerical ranges may be replaced with the values shown in the embodiments.

<Adhesive composition>
The adhesive composition of the present embodiment includes (a) a thermoplastic resin having a urethane bond (hereinafter, also referred to as a component (a)), (b) a radical polymerizable compound (hereinafter, also referred to as a component (b)), ( c) 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 fine particles (hereinafter referred to as component (e)) (Also referred to as an adhesive composition). The adhesive composition of the present embodiment may further contain (f) conductive particles (hereinafter, also referred to as component (f)). The adhesive composition of the present embodiment can be suitably used as an adhesive composition for circuit connection. Hereinafter, each component will be described.

(Thermoplastic resin)
The thermoplastic resin (a) having a urethane bond (hereinafter, referred to as a polyurethane resin) used in the present embodiment can be obtained, for example, by reacting a polyol with an isocyanate component such as diisocyanate. The weight average molecular weight of the polyurethane resin is preferably from 5,000 to 150,000, more preferably from 10,000 to 80,000. When this value is 5,000 or more, the film formability tends to be good when the adhesive composition is used in the form of a film, and when it is 150,000 or less, the compatibility with other components is good. It tends to be.

  Examples of the polyol used for synthesizing the polyurethane resin include polyester polyol, polyether polyol, polycarbonate polyol, acrylic polyol, polyurethane polyol, aromatic polyol (phthalic acid polyol), and the like. Specific examples include those having a basic skeleton of ethylene glycol, propylene glycol, 1,4-butanediol, 1,6-hexanediol, neopentyl glycol, triethylene glycol, or the like. These can be used alone or in combination of two or more.

  Examples of the isocyanate component include diisocyanate compounds such as aromatic diisocyanates, aliphatic diisocyanates, and alicyclic diisocyanates. Specifically, 4,4'-diphenylmethane diisocyanate (MDI), tolylene diisocyanate (TDI), trimethylene diisocyanate, tetramethylene diisocyanate, hexamethylene diisocyanate (HDI), 3-isocyanatomethyl-3,5,5-trimethyl Cyclohexyl isocyanate (IPDI) and the like. Further, as the isocyanate component, an isocyanurate compound (trifunctional) or a uretdione compound (bifunctional) formed from the diisocyanate monomer can also be used. Furthermore, terminal isocyanate group polyisocyanate (for example, adduct type polyisocyanate, biuret type polyisocyanate, etc.) can be used as the isocyanate component. These can be used alone or in combination of two or more.

  The content of the polyurethane resin in the adhesive composition is preferably not less than (d) the content of the polyurethane beads on a mass basis. When the content of the polyurethane resin is equal to or more than the content of the polyurethane beads, the dispersibility of the polyurethane beads in the adhesive composition is more due to the relatively large amount of the polyurethane resin having a high affinity for the polyurethane beads. Tends to improve. The content of the polyurethane resin is 5 to 90 mass% based on the total mass of the adhesive component (solid content other than (f) conductive particles in the adhesive composition; the same applies hereinafter) of the adhesive composition. %, More preferably 6 to 80% by mass, still more preferably 8 to 70% by mass, and particularly preferably 10 to 60% by mass. When the content of the polyurethane resin is 5% by mass or more, the dispersibility of the polyurethane beads tends to be improved and the adhesive strength tends to be further improved. When the content is 90% by mass or less, the flowability of the adhesive composition is good. Tend to be able to.

  The adhesive composition of the present embodiment can use a known thermoplastic resin other than the polyurethane resin in combination. Examples of the thermoplastic resin other than the polyurethane resin include one or more resins selected from a polyimide resin, a polyamide resin, a phenoxy resin, a poly (meth) acrylic resin, a polyester resin, and a polyvinyl butyral resin.

  The weight average molecular weight of such a thermoplastic resin is preferably 5,000 to 400,000, more preferably 5,000 to 200,000, and still more preferably 10,000 to 150,000. When the weight average molecular weight of such a thermoplastic resin is 5,000 or more, the adhesive strength of the adhesive composition tends to be good, and when the weight average molecular weight is 400,000 or less, the compatibility with other components is poor. It is good and tends to be able to suppress a decrease in the fluidity of the adhesive.

  As the thermoplastic resin, a rubber component can be used for the purpose of relaxing stress and improving adhesiveness. Examples of rubber components include acrylic rubber, polyisoprene, polybutadiene, carboxyl-terminated polybutadiene, hydroxyl-terminated polybutadiene, 1,2-polybutadiene, carboxyl-terminated 1,2-polybutadiene, hydroxyl-terminated 1,2-polybutadiene, and 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 Can be It is preferable that the rubber component has a cyano group or a carboxyl group, which is a highly polar group, as a side chain group or a terminal group from the viewpoint of improving adhesion. These rubber components can be used alone or in combination of two or more.

  The content of the entire thermoplastic resin in the adhesive composition is preferably from 20 to 90% by mass, more preferably from 20 to 80% by mass, based on the total mass of the adhesive component of the adhesive composition. More preferably, it is 30 to 70% by mass. (A) When the content of the thermoplastic resin is 20% by mass or more, the film forming property of the adhesive composition tends to be improved while improving the adhesive strength. When the content is 90% by mass or less, the adhesive is used. There is a tendency that the fluidity of the composition can be improved.

(Radical polymerizable compound)
(B) The radically polymerizable compound is a compound having a radically polymerizable functional group. Examples of such radical polymerizable compounds include (meth) acrylate compounds, maleimide compounds, citraconic imide resins, and nadimide resins. “(Meth) acrylate compound” means a compound having a (meth) acryloyl group. The radical polymerizable compound may be used in a state of a monomer or an oligomer, or a monomer and an oligomer may be used in combination. The radical polymerizable compound may be used alone or in a combination of two or more.

  Specific examples of the (meth) acrylate compound 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, tetramethylolmethanetetra (meth) acrylate, 2-hydroxy-1,3-di (meth) acryloxypropane, 2,2-bis [4-((meth) acryloxymethoxy) Phenyl] propane, 2,2-bis [4-((meth) acryloxypolyethoxy) phenyl] propane, dicyclopentenyl (meth) acrylate, tricyclodecanyl (meth) acrylate, tris ((meth) acryloyloxy) Etch ) Isocyanurate, urethane (meth) acrylate, isocyanuric acid EO-modified di (meth) acrylate, 9,9-bis [4- (2- (meth) acryloyloxy ethoxy) phenyl] fluorene, and the like. As the radical polymerizable compound other than the (meth) acrylate compound, for example, a compound described in Patent Document 3 (WO 2009/063827) can be suitably used. The (meth) acrylate compounds may be used alone or in combination of two or more.

  As the radical polymerizable compound, a (meth) acrylate compound is preferable, and urethane (meth) acrylate is more preferable, from the viewpoint of obtaining further excellent storage stability. The (meth) acrylate compound preferably has at least one substituent selected from the group consisting of a dicyclopentenyl group, a tricyclodecanyl group, and a triazine ring from the viewpoint of improving heat resistance.

  Further, as the radical polymerizable compound, it is preferable to use a radical polymerizable compound having a phosphate ester structure represented by the following general formula (1), and the radical polymerizable compound such as a (meth) acrylate compound, It is more preferable to use together with the radical polymerizable compound having a phosphate ester structure represented by 1). In these cases, since the adhesive strength to the surface of the inorganic substance (metal or the like) is improved, it is suitable for, for example, bonding between circuit electrodes.

［式中、ｐは１〜３の整数を示し、Ｒは、水素原子又はメチル基を示す。］

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

  The radical polymerizable compound having a phosphate ester structure is obtained, for example, by reacting phosphoric anhydride with 2-hydroxyethyl (meth) acrylate. Specific examples of the radical polymerizable compound having a phosphate ester structure include mono (2- (meth) acryloyloxyethyl) acid phosphate, di (2- (meth) acryloyloxyethyl) acid phosphate, and the like. . The radical polymerizable compound having a phosphate ester structure represented by the formula (1) may be used alone or in combination of two or more.

  The content of the radically polymerizable compound having a phosphate ester structure represented by the formula (1) is determined from the viewpoint of obtaining further excellent adhesiveness from the viewpoint of obtaining a radically polymerizable compound (total amount of components corresponding to the radically polymerizable compound. 1) to 100% by mass, more preferably 1 to 50% by mass, even more preferably 1 to 10% by mass, based on the total mass of the same). The content of the radical polymerizable compound having a phosphate ester structure represented by the formula (1) is determined based on the content of the radical polymerizable compound and the film forming material (component used as necessary) from the viewpoint of obtaining more excellent adhesion. 0.01 to 50% by mass, preferably 0.5 to 10% by mass, and more preferably 0.5 to 5% by mass, based on the total mass.

  The radical polymerizable compound may include allyl (meth) acrylate. In this case, the content of the allyl (meth) acrylate is preferably from 0.1 to 10% by mass, and more preferably from 0.5 to 10% by mass, based on the total mass of the radically polymerizable compound and the film-forming material (component used if necessary). 5 mass% is more preferable.

  The content of the radical polymerizable compound is preferably within the following range based on the total mass of the adhesive component of the adhesive composition, from the viewpoint of obtaining more excellent adhesiveness. The content of the radical polymerizable compound is preferably 10% by mass or more, more preferably 20% by mass or more, further preferably 30% by mass or more, and further preferably 40% by mass or more. preferable. The content of the radical polymerizable compound is preferably 90% by mass or less, more preferably 80% by mass or less, further preferably 70% by mass or less, and particularly preferably 60% by mass or less. It is very preferably at most 50% by mass. From these viewpoints, the content of the radical polymerizable compound is preferably from 10 to 90% by mass, more preferably from 20 to 80% by mass, still more preferably from 30 to 70% by mass, and more preferably 40 to 70% by mass. It is particularly preferable that the content is from 60 to 60% by mass, and it is particularly preferable that the content is from 40 to 50% by mass.

(Radical polymerization initiator)
(C) As the radical polymerization initiator, an initiator that generates free radicals by heat (heating), an initiator that generates free radicals by light, an initiator that generates free radicals by ultrasonic waves, electromagnetic waves, or the like is used. Can be.

  An initiator that generates free radicals by heat is a compound that decomposes by heat to generate free radicals. Such compounds include peroxides (such as organic peroxides) and azo compounds. Such a radical polymerization initiator is appropriately selected depending on the intended connection temperature, connection time, pot life, and the like. From the viewpoints of stability, reactivity and compatibility, a peroxide having a one-minute half-life temperature of 90 to 175 ° C and a molecular weight of 180 to 1000 is preferable. "One minute half-life temperature" refers to the temperature at which the half-life of the peroxide is one minute. "Half-life" refers to the time it takes for the concentration of a compound to decrease to half its initial value at a given temperature. The one-minute half-life temperature is a value described in a catalog (organic peroxide (10th edition, February 2015)) issued by NOF Corporation.

  Specific examples of initiators that generate free radicals by heat include diacyl peroxide, peroxydicarbonate, peroxyester, peroxyketal, dialkyl peroxide, hydroperoxide, silyl peroxide, and the like.

  As the radical polymerization initiator, from the viewpoint of suppressing corrosion of an electrode (such as a circuit electrode), an initiator having a concentration of chlorine ion and an organic acid of 5000 ppm or less is preferable, and an organic acid generated after thermal decomposition is less. Agents are more preferred. Specific examples of such an initiator include peroxyesters, dialkyl peroxides, hydroperoxides, silyl peroxides, and the like. Peroxyesters are more preferable from the viewpoint of obtaining high reactivity.

  Examples of the radical polymerization initiator include 1,1,3,3-tetramethylbutylperoxy neodecanoate, di (4-t-butylcyclohexyl) peroxydicarbonate, and di (2-ethylhexyl) peroxydicarbonate. Carbonate, cumyl peroxy neodecanoate, 1,1,3,3-tetramethylbutyl peroxy neodecanoate, dilauroyl peroxide, 1-cyclohexyl-1-methylethyl peroxy neodecanoate, t- Hexyl peroxy neodecanoate, t-butyl peroxy neodecanoate, t-butyl peroxy pivalate, 1,1,3,3-tetramethylbutyl peroxy-2-ethylhexanoate, 2,5 -Dimethyl-2,5-di (2-ethylhexanoylperoxy) hexane, t-hexylpa Oxy-2-ethylhexanoate, t-butylperoxy-2-ethylhexanoate, t-butylperoxyneoheptanoate, t-amylperoxy-2-ethylhexanoate, di-t-butyl Peroxyhexahydroterephthalate, t-amylperoxy-3,5,5-trimethylhexanoate, 3-hydroxy-1,1-dimethylbutylperoxyneodecanoate, 1,1,3,3-tetramethyl Butyl peroxy-2-ethylhexanoate, t-amyl peroxy neodecanoate, t-amyl peroxy-2-ethyl hexanoate, 3-methylbenzoyl peroxide, 4-methylbenzoyl peroxide, di ( 3-methylbenzoyl) peroxide, dibenzoyl peroxide, di (4-methyl Zoyl) peroxide, 2,2′-azobis-2,4-dimethylvaleronitrile, 1,1′-azobis (1-acetoxy-1-phenylethane), 2,2′-azobisisobutyronitrile, , 2'-Azobis (2-methylbutyronitrile), dimethyl-2,2'-azobisisobutyronitrile, 4,4'-azobis (4-cyanovaleric acid), 1,1'-azobis (1- Cyclohexanecarbonitrile), t-hexylperoxyisopropyl monocarbonate, t-butylperoxymaleic acid, t-butylperoxy-3,5,5-trimethylhexanoate, t-butylperoxylaurate, 2,5 -Dimethyl-2,5-di (3-methylbenzoylperoxy) hexane, t-butylperoxy-2-ethylhexyl monocarbo Tert-hexylperoxybenzoate, 2,5-dimethyl-2,5-di (benzoylperoxy) hexane, t-butylperoxybenzoate, dibutylperoxytrimethyl adipate, t-amylperoxy normal octoate, t -At least one compound selected from amyl peroxy isononanoate and t-amyl peroxy benzoate.

  Initiators that generate free radicals by light are compounds that decompose by light to generate free radicals. As such an initiator, a compound that generates free radicals by irradiation with light having a wavelength of 150 to 750 nm can be used. As such a compound, for example, from the viewpoint of high sensitivity to light irradiation, Photoinitiation, Photopolymerization, and Photocuring, J. Am. -P. Preferred are α-acetaminophenone derivatives and phosphine oxide derivatives described in Fouassier, Hanser Publishers (1995), pp. 17-35.

  One kind of the radical polymerization initiator may be used alone, or two or more kinds may be used in combination. The initiator may be used in combination with a decomposition accelerator, a decomposition inhibitor, and the like. Further, the initiator may be covered with a polyurethane-based or polyester-based polymer substance or the like to be microencapsulated. Microencapsulated initiators are preferred for extended pot life.

  The content of the radical polymerization initiator is preferably from 1 to 15 parts by mass, more preferably from 2.5 to 10 parts by mass, based on 100 parts by mass of the total of the components (a) and (b). .

(Polyurethane beads)
The polyurethane beads (d) used in this embodiment are spherical organic fine particles made of a cross-linked urethane resin.

  Polyurethane beads can be synthesized by reacting a polyol component and an isocyanate component. As the polyol, a bifunctional one is mainly used, but a trifunctional or more functional polyol may be used in combination. When a combination of three or more functional groups is used, the degree of crosslinking of the polyurethane beads can be increased.

  Examples of the polyol component include polyester polyols, polyether polyols, polycarbonate polyols, acrylic polyols, polyurethane polyols, aromatic polyols (phthalic polyols), and the like. Of these, polycarbonate polyols or aromatic polyols are preferred from the viewpoint of improving hydrolysis resistance. As the polyol, a polyfunctional polyol is preferable from the viewpoint of increasing the degree of crosslinking of the polyurethane beads and increasing the elastic recovery. Examples of the polyfunctional polyol include a trifunctional polycaprolactone-based polyol. The higher the weight average molecular weight of the polyfunctional polyol, the higher the flexibility. These can be used alone or in combination of two or more.

  The isocyanate component may be any of a yellowing type, a non-yellowing type, and a non-yellowing type. Examples of the isocyanate component include diisocyanate compounds such as aromatic diisocyanates, aliphatic diisocyanates, and alicyclic diisocyanates. Specifically, for example, 4,4'-diphenylmethane diisocyanate (MDI), tolylene diisocyanate (TDI), trimethylene diisocyanate, tetramethylene diisocyanate, hexamethylene diisocyanate (HDI), 3-isocyanatomethyl-3,5,5 -Trimethylcyclohexyl isocyanate (IPDI) and the like. Further, as the isocyanate component, an isocyanurate compound (trifunctional) or a uretdione compound (bifunctional) formed from the diisocyanate monomer can also be used. Furthermore, terminal isocyanate group polyisocyanate (for example, adduct type polyisocyanate, biuret type polyisocyanate, etc.) can be used as the isocyanate component. These can be used alone or in combination of two or more.

  The average particle size of the polyurethane beads is not particularly limited, but is preferably from 50 nm to 10 μm, more preferably from 70 nm to 6 μm, and still more preferably from 70 nm to 5 μm. Since it may be technically difficult to produce polyurethane beads of less than 50 nm, it is preferably at least 50 nm from the viewpoint of availability. When the thickness is 10 μm or less, aggregation does not easily occur when blended with another adhesive composition, and even if aggregation occurs, deterioration of filterability tends to be suppressed. The average particle size can be confirmed, for example, by SEM.

  It is preferable that the content of the polyurethane beads is less than the content of the polyurethane resin as the component (a). In addition, it is preferably 3 to 50% by mass, more preferably 4 to 40% by mass, and more preferably 5 to 30% by mass based on the total mass of the adhesive component of the adhesive composition. Is more preferably, and particularly preferably 8 to 25% by mass. When the content is 3% by mass or more, sufficient adhesive strength tends to be easily obtained, and when the content is 50% by mass or less, a decrease in the fluidity of the adhesive tends to be suppressed.

(Non-conductive inorganic fine particles)
As the non-conductive inorganic fine particles of the component (e), known non-conductive inorganic fine particles can be used without any particular limitation. Examples of the non-conductive inorganic fine particles include non-conductive inorganic fine particles such as metal oxide fine particles such as silica fine particles, alumina fine particles, silica-alumina fine particles, titania fine particles, and zirconia fine particles. These can be used alone or in combination of two or more. In this embodiment, (e) the non-conductive inorganic fine particles do not have conductivity, and do not belong to (f) conductive particles described later.

  The average particle diameter of the non-conductive inorganic fine particles is preferably less than 1 μm, more preferably 0.1 to 0.5 μm. Here, the average particle diameter is a mode diameter in the major axis direction when present in the circuit connecting material. The average primary particle diameter of the component (e) is preferably 100 nm or less, more preferably 10 to 30 nm. In this specification, the average particle diameter and the average primary particle diameter indicate values measured by image analysis.

  As the non-conductive inorganic fine particles, fine particles having a surface modified with an organic group can be suitably used because of their excellent dispersibility. Examples of the organic group include a dimethylsiloxane group and a diphenylsiloxane group.

  The content of the non-conductive inorganic fine particles is preferably 1 to 30% by mass, more preferably 2 to 25% by mass, and more preferably 5 to 20% by mass based on the total mass of the adhesive component. Is more preferred. When the content of the component (e) is within the above range, the effects of the present disclosure are more remarkably exhibited.

(Conductive particles)
The adhesive composition of the present embodiment may further contain (f) conductive particles. Examples of the constituent material of the conductive particles include gold (Au), silver (Ag), nickel (Ni), copper (Cu), metals such as solder, and carbon. Further, coated conductive particles having a core of non-conductive resin, glass, ceramic, plastic, or the like, and coating the core with the above-described metal (metal particles or the like) or carbon may be used. The coated conductive particles or hot-melt metal particles have deformability due to heating and pressurization, thereby eliminating variations in the height of circuit electrodes during connection and increasing the contact area with the electrodes during connection, thereby improving reliability. Therefore, it is preferable.

  The average particle size of the conductive particles is preferably 1 to 30 μm, more preferably 2 to 25 μm, and still more preferably 3 to 20 μm, from the viewpoint of excellent dispersibility and conductivity. The average particle size of the conductive particles can be measured using, for example, instrumental analysis such as a laser diffraction method.

  The content of the conductive particles is preferably at least 0.1 part by volume, more preferably at least 1 part by volume, based on 100 parts by volume of the total volume of the adhesive component of the adhesive composition, from the viewpoint of excellent conductivity. The content of the conductive particles is preferably equal to or less than 50 parts by volume, and more preferably equal to or less than 20 parts by volume, based on the total volume of the adhesive component of the adhesive composition, from the viewpoint of easily suppressing a short circuit of an electrode (such as a circuit electrode). The content is preferably 10 parts by volume or less, more preferably 5 parts by volume or less, particularly preferably 3 parts by volume or less. From these viewpoints, the content of the 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, and particularly preferably 1 to 10 parts by volume. , 1 to 5 parts by volume, very preferably 1 to 3 parts by volume. The “volume part” 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 is put into a container in which a suitable solvent (water, alcohol, etc.) that does not dissolve or swell the target component and wets the target component well is placed in a measuring cylinder or the like, and the increased volume is taken as the volume of the target component. Can also be sought.

(Silane coupling agent)
The adhesive composition according to the present embodiment may contain a silane coupling agent. The silane coupling agent is preferably a compound represented by the following formula (2).

式（２）中、Ｒ^１、Ｒ^２及びＲ^３はそれぞれ独立に、水素原子、炭素数１〜５のアルキル基、炭素数１〜５のアルコキシ基、炭素数１〜５のアルコキシカルボニル基又はアリール基を示す。Ｒ^１、Ｒ^２及びＲ^３のうち少なくとも１つはアルコキシ基である。Ｒ^４は（メタ）アクリロイル基、（メタ）アクリロイルオキシ基、ビニル基、イソシアネート基、イミダゾール基、メルカプト基、アミノアルキル基で置換されていてもよいアミノ基、メチルアミノ基、ジメチルアミノ基、ベンジルアミノ基、フェニルアミノ基、シクロヘキシルアミノ基、モルホリノ基、ピペラジノ基、ウレイド基、グリシジル基又はグリシドキシ基を示す。ａは０〜１０の整数を示す。

In the formula (2), R ¹ , R ² and R ³ are each independently 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 Indicates an aryl group. At least one of R ¹ , R ² and R ³ is an alkoxy group. R ⁴ represents a (meth) acryloyl group, a (meth) acryloyloxy group, a vinyl group, an isocyanate group, an imidazole group, a mercapto group, an amino group optionally substituted with an aminoalkyl group, a methylamino group, a dimethylamino group, or a benzyl group. It represents an amino group, a phenylamino group, a cyclohexylamino group, a morpholino group, a piperazino group, a ureido group, a glycidyl group or a glycidoxy group. a shows the integer of 0-10.

  Examples of the silane coupling agent of the formula (2) include vinyltrimethoxysilane, vinyltriethoxysilane, 3-glycidoxypropyltrimethoxysilane, 3-glycidoxypropylmethyldiethoxysilane, and 3- (meth) Acryloxypropylmethyldimethoxysilane, 3- (meth) acryloxypropyltrimethoxysilane, 3- (meth) acryloxypropylmethyldiethoxysilane, 3- (meth) acryloxypropyltriethoxysilane, N-2- (amino Ethyl) -3-aminopropylmethyldimethoxysilane, N-phenyl-3-aminopropyltrimethoxysilane, 3-ureidopropyltriethoxysilane, 3-mercaptopropyltrimethoxysilane and 3-isocyanatopropyltriethoxysilane .

  The content of the silane coupling agent is preferably from 0.1 to 10 parts by mass, and more preferably from 0.25 to 5 parts by mass, based on 100 parts by mass of the components (a) and (b). Is more preferred. If the content of the silane coupling agent is 0.1 parts by mass or more, the effect of suppressing the separation of the interface between the circuit member and the circuit connection material, and the generation of bubbles tends to be greater, and the silane coupling agent When the content is 10 parts by mass or less, the pot life of the adhesive composition tends to be long.

(Other components)
The adhesive composition of the present embodiment may appropriately contain a polymerization inhibitor such as hydroquinone and methyl ether hydroquinone, if necessary.

  The adhesive composition of the present embodiment comprises a homopolymer or a copolymer obtained by polymerizing at least one monomer component selected from the group consisting of (meth) acrylic acid, (meth) acrylic acid ester and acrylonitrile. Further, it may be contained. From the viewpoint of excellent stress relaxation, the adhesive composition of the present embodiment preferably contains acrylic rubber or the like, which is a copolymer obtained by polymerizing glycidyl (meth) acrylate having a glycidyl ether group. The weight average molecular weight of the acrylic rubber is preferably 200,000 or more from the viewpoint of increasing the cohesive strength of the adhesive composition.

  The adhesive composition of the present embodiment may contain coated fine particles obtained by coating the surface of the conductive particles with a polymer resin or the like. When such coated fine particles are used in combination with the conductive particles, even when the content of the conductive particles is increased, short-circuiting due to contact between the conductive particles is easily suppressed, so that the insulating property between adjacent circuit electrodes is reduced. Can be improved. The coated fine particles may be used alone without using the conductive particles, or the coated fine particles and the conductive particles may be used in combination. In the case where the adhesive composition contains coated fine particles, the “adhesive component of the adhesive composition” in this specification means a solid content other than the conductive particles and the coated fine particles in the adhesive composition.

  The adhesive composition of the present embodiment can also contain rubber fine particles, a filler, a softener, an accelerator, an antioxidant, a coloring agent, a flame retardant, a thixotropic agent, and the like. Further, the adhesive composition of the present embodiment may appropriately contain additives such as a thickener, a leveling agent, and a weather resistance improver.

  The rubber fine particles have an average particle size of twice or less the average particle size of the conductive particles, and the storage elastic modulus at room temperature is の of the storage elastic modulus of the conductive particles and the adhesive composition at room temperature. The following particles are preferred. In particular, when the material of the rubber fine particles is silicone, acrylic emulsion, SBR (Styrene-Butadiene Rubber), NBR (Nitril-Butadiene Rubber) or polybutadiene rubber, the rubber fine particles may be used alone or in combination of two or more. Is preferred. The three-dimensionally crosslinked rubber fine particles have excellent solvent resistance and are easily dispersed in the adhesive composition.

  The filler can improve electric characteristics (connection reliability and the like) between circuit electrodes. As the filler, for example, particles having an average particle size of 1/2 or less of the average particle size of the conductive particles can be suitably used. When non-conductive particles are used in combination with the filler, particles having an average particle size equal to or less than the non-conductive particles can be used as the filler. The content of the filler is preferably 0.1 to 60% by mass based on the total amount of the adhesive components of the adhesive composition. When the content is 60% by mass or less, the effect of improving connection reliability tends to be more sufficiently obtained. When the content is 0.1% by mass or more, the effect of adding the filler tends to be sufficiently obtained.

  The adhesive composition of the present embodiment can be used in the form of a paste when it is liquid at normal temperature. When the adhesive composition is solid at room temperature, it may be used by heating or pasting using a solvent. The solvent that can be used is not particularly limited as long as it has no reactivity with components in the adhesive composition and shows sufficient solubility. The solvent is preferably a solvent having a boiling point at normal pressure of 50 to 150 ° C. When the boiling point is 50 ° C. or higher, the solvent is poor in volatility at room temperature, so that it can be used even in an open system. When the boiling point is 150 ° C. or lower, it is easy to volatilize the solvent, so that good reliability is obtained after bonding.

  The adhesive composition of the present embodiment may be in the form of a film. If necessary, an adhesive composition containing a solvent or the like is applied to, for example, a fluororesin film, a polyethylene terephthalate film, or a peelable substrate (release paper or the like), and then the solvent or the like is removed to remove the film. Adhesive composition can be obtained. Further, a film-like adhesive composition can be obtained by impregnating a base material such as a nonwoven fabric with the above solution and placing the base material on a peelable base material and then removing the solvent and the like. When the adhesive composition is used in the form of a film, it is excellent in handleability and the like.

The adhesive composition of the present embodiment can be bonded by heating or pressurizing with light irradiation. By using both heating and light irradiation, bonding can be performed at a lower temperature and in a shorter time. Light irradiation is preferably performed with light in a wavelength range of 150 to 750 nm. As a light source, 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, a metal halide lamp, or the like can be used. The irradiation dose may be 0.1 to 10 J / cm ² . The heating temperature is not particularly limited, but a temperature of 50 to 170C is preferable. The pressure is not particularly limited as long as the pressure does not damage the adherend, but is preferably 0.1 to 10 MPa. Heating and pressurization are preferably performed in the range of 0.5 seconds to 3 hours.

  The adhesive composition of the present embodiment may be used as an adhesive for adherends of the same type, or may be used as an adhesive for adherends of different types having different coefficients of thermal expansion. Specifically, circuit connection materials typified by anisotropic conductive adhesives, silver pastes, silver films, etc .; CSP (Chip Size Package) elastomers, CSP underfill materials, LOC (Lead on Chip) tapes, etc. It can be used as a semiconductor element adhesive material to be used.

<Structure and manufacturing method thereof>
The structure of the present embodiment includes the adhesive composition of the present embodiment or a cured product thereof. The structure of the present embodiment is, for example, a semiconductor device such as a circuit connection structure. As one aspect of the structure of the present embodiment, 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 first circuit member. And a circuit connecting member arranged between the second circuit member. The first circuit member has, for example, a first substrate, and a first circuit electrode arranged on the first substrate. The second circuit member has, for example, a second substrate and a second circuit electrode disposed on the second substrate. The first circuit electrode and the second circuit electrode face each other and are electrically connected. The circuit connecting member includes the adhesive composition of the present embodiment or a cured product thereof. The structure according to the present embodiment only needs to include the adhesive composition or the cured product thereof according to the present embodiment. Instead of the circuit member of the circuit connection structure, a member having no circuit electrode ( Substrate, etc.).

  The method for manufacturing a structure of the present embodiment includes a step of curing the adhesive composition of the present embodiment. As one aspect of the method for manufacturing a structure of the present embodiment, the method for manufacturing a circuit connection structure includes a first circuit member having a first circuit electrode, and a second circuit member having a second circuit electrode. In the meantime, the arranging step of arranging the adhesive composition of the present embodiment, the first circuit member and the second circuit member are pressed to electrically connect the first circuit electrode and the second circuit electrode. And a heating and pressurizing step of heating and curing the adhesive composition. In the arranging step, the first circuit electrode and the second circuit electrode can be arranged so as to face each other. In the heating and pressurizing step, the first circuit member and the second circuit member can be pressurized in opposite directions.

  Hereinafter, a circuit connection structure and a method for manufacturing the circuit connection structure will be described as one embodiment of the present embodiment with reference to the drawings. FIG. 1 is a schematic sectional view showing an embodiment of the structure. The circuit connection structure 100a shown in FIG. 1 includes a circuit member (first circuit member) 20 and a circuit member (second circuit member) 30 facing each other. Is provided with a circuit connecting member 10 for connecting them. The circuit connecting member 10 includes a cured product of the adhesive composition of the present embodiment.

  The circuit member 20 includes a substrate (first substrate) 21 and a circuit electrode (first circuit electrode) 22 disposed on a main surface 21 a of the substrate 21. On the main surface 21a of the substrate 21, an insulating layer (not shown) may be arranged as the case may be.

  The circuit member 30 includes a substrate (second substrate) 31 and a circuit electrode (second circuit electrode) 32 disposed on the main surface 31 a of the substrate 31. On the main surface 31a of the substrate 31, an insulating layer (not shown) may be arranged as the case may be.

  The circuit connecting member 10 contains an insulating substance (a cured product of a component excluding conductive particles) 10a and conductive particles 10b. The conductive particles 10b are arranged at least between the opposing circuit electrodes 22 and 32. In the circuit connection structure 100a, the circuit electrode 22 and the circuit electrode 32 are electrically connected via the conductive particles 10b.

  The circuit members 20 and 30 have one or more circuit electrodes (connection terminals). As the circuit members 20 and 30, for example, members having electrodes that require electrical connection can be used. As the circuit member, chip components such as a semiconductor chip (IC chip), a resistor chip, and a capacitor chip; substrates such as a printed board and a semiconductor mounting board can be used. Examples of the combination of the circuit members 20 and 30 include a semiconductor chip and a semiconductor mounting substrate. Examples of the material of the substrate include inorganic substances such as semiconductors, glass, and ceramics; organic substances such as polyimide, polyethylene terephthalate, polycarbonate, (meth) acrylic resin, and cyclic olefin resin; and composites of glass and epoxy. The substrate may be a plastic substrate.

  FIG. 2 is a schematic sectional view showing another embodiment of the structure. The circuit connection structure 100b shown in FIG. 2 has the same configuration as the circuit connection structure 100a except that the circuit connection member 10 does not contain the conductive particles 10b. In the circuit connection structure 100b shown in FIG. 2, the circuit electrode 22 and the circuit electrode 32 are directly contacted and electrically connected without interposing the conductive particles.

  The circuit connection structures 100a and 100b can be manufactured, for example, by the following method. First, when the adhesive composition is in the form of a paste, the resin layer containing the adhesive composition is disposed on the circuit member 20 by applying and drying the adhesive composition. When the adhesive composition is in the form of a film, the resin layer containing the adhesive composition is disposed on the circuit member 20 by attaching the film-like adhesive composition to the circuit member 20. Subsequently, the circuit member 30 is placed on the resin layer disposed on the circuit member 20 so that the circuit electrode 22 and the circuit electrode 32 are arranged to face each other. Then, by subjecting the resin layer containing the adhesive composition to heat treatment or light irradiation, the adhesive composition is cured to obtain a cured product (circuit connecting member 10). Thus, circuit connection structures 100a and 100b are obtained.

  Hereinafter, the present disclosure will be described more specifically with reference to Examples and Comparative Examples. However, the present disclosure is not limited to the following embodiments.

(Synthesis of polyurethane resin)
In a separable flask equipped with a reflux condenser, a thermometer, and a 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 having an ether bond, and methyl ethyl ketone ( After adding 4,000 parts by mass of a solvent, the mixture was stirred at 40 ° C. for 30 minutes to prepare a reaction solution. After the temperature of the reaction solution was raised to 70 ° C., 0.0127 parts by mass of dimethyltin laurate (catalyst) was 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. Thereafter, stirring was continued at the above temperature until an absorption peak (2270 cm ^-1 ) derived from an isocyanate group was not observed by an infrared spectrophotometer (manufactured by JASCO Corporation) to obtain a methyl ethyl ketone solution of polyurethane. Next, the amount of the solvent was adjusted so that the solid content concentration (polyurethane concentration) of this solution was 30% by mass. The weight average molecular weight of the obtained polyurethane (polyurethane resin) was 320,000 (standard polystyrene equivalent) as a result of measurement by GPC (gel permeation chromatography). Table 1 shows the measurement conditions of GPC.

(Synthesis of urethane acrylate)
In a 2 L (liter) four-necked flask equipped with a thermometer, a stirrer, an inert gas inlet and a reflux condenser, 4000 parts by mass of polycarbonate diol (manufactured by Aldrich, number average molecular weight 2000) and 2-hydroxyethyl A reaction liquid was prepared by charging 238 parts by mass of acrylate, 0.49 parts by mass of hydroquinone monomethyl ether, and 4.9 parts by mass of a tin-based catalyst. To the reaction solution heated to 70 ° C., 666 parts by mass of isophorone diisocyanate (IPDI) was uniformly dropped over 3 hours to cause a reaction. After the completion of the dropwise addition, the reaction was continued for 15 hours. When the NCO% (NCO content) became 0.2% by mass or less, the reaction was regarded as completed, and a urethane acrylate was obtained. The NCO% was confirmed by an automatic potentiometric titrator (trade name: AT-510, manufactured by Kyoto Electronics Industry Co., Ltd.). As a result of analysis by GPC, the weight average molecular weight of urethane acrylate was 8,500 (standard polystyrene equivalent). The analysis by GPC was performed under the same conditions as the analysis of the weight average molecular weight of the polyurethane resin.

(Production of conductive particles)
A nickel layer having a thickness of 0.2 μm was formed on the surface of the polystyrene particles. Further, a gold layer having a thickness of 0.04 μm was formed outside the nickel layer. Thus, conductive particles having an average particle size of 4 μm were produced.

[Examples 1 to 7 and Comparative Examples 1 to 4]
(Preparation of film adhesive)
The components shown in Table 2 were mixed at the mass ratio (solid content) shown in Table 2 to obtain a mixture. The conductive particles are dispersed in the mixture at a ratio of 1.5 parts by volume (reference: ratio to 100 parts by volume of the total volume of the adhesive component of the adhesive composition) to form a coating for forming a film adhesive. A liquid was obtained. This coating solution was applied to a 50 μm-thick polyethylene terephthalate (PET) film using a coating apparatus. The coating film was dried with hot air at 70 ° C. for 10 minutes to form a film adhesive having a thickness of 18 μm.

The details of each component shown in Table 2 are as follows.
Polyurethane resin: The polyurethane resin synthesized as described above was used.
Phenoxy resin: A 40% by mass solution prepared by dissolving 40 g of PKHC (trade name, weight average molecular weight: 45,000, manufactured by Union Carbide Co., Ltd.) in 60 g of methyl ethyl ketone was used.
Radical polymerizable compound A: urethane acrylate synthesized as described above was used.
Radical polymerizable compound B: Isocyanuric acid EO-modified diacrylate (trade name: M-215, manufactured by Toagosei Co., Ltd.) was used.
Radical polymerizable compound C (phosphate ester): 2-methacryloyloxyethyl acid phosphate (trade name: Light Ester P-2M, manufactured by Kyoeisha Chemical Co., Ltd.) was used.
Peroxide (radical polymerization initiator): 1,1,3,3-tetramethylbutylperoxy-2-ethylhexanoate (trade name: Perocta O, manufactured by NOF Corporation, 1 minute half-life temperature: 124 .3 ° C.).
Polyurethane beads A: 10 g of P-800T (trade name, manufactured by Negami Kogyo Co., Ltd., average particle diameter: 6 μm, glass transition temperature: −34 ° C.) was used in the form of a 10% by mass solution dispersed in 90 g of methyl ethyl ketone.
Polyurethane beads B: 10 g of JB-800T (trade name, manufactured by Negami Kogyo Co., Ltd., average particle diameter: 6 μm, glass transition temperature: −52 ° C.) was used in the form of a 10% by mass solution dispersed in 90 g of methyl ethyl ketone.
Silica fine particles (non-conductive inorganic fine particles): used in the form of a 10% by mass dispersion of 10 g of R104 (trade name, manufactured by Nippon Aerosil Co., Ltd.) in a mixed solvent of 45 g of toluene and 45 g of ethyl acetate.

(Production of connection body)
Using the film-like adhesives of Examples 1 to 7 and Comparative Examples 1 to 4, a flexible circuit board (FPC) having 2200 copper circuits having a line width of 75 μm, a pitch of 150 μm (space 75 μm) and a thickness of 18 μm, and glass The substrate was connected to a SiN _x substrate (0.7 mm thick) having a thin layer of silicon nitride (SiN _x ) with a thickness of 0.2 μm formed on a glass substrate. The connection was performed by heating and pressing at 170 ° C. and 3 MPa for 5 seconds using a thermocompression bonding apparatus (heating method: constant heat type, manufactured by Toray Engineering Co., Ltd.). Thus, to produce the FPC and SiN _x substrate across width 1.5mm and width 1.0mm connected connection member by the cured product of the adhesive film (the structure). Pressure of the pressure, the pressure bonding area in the case of width 1.5mm 0.495cm ^2, in the case of width 1.0mm was calculated as 0.330cm ^2.

<Measurement of adhesive strength>
The adhesive strength of the obtained connector was measured by a 90-degree peeling method according to JIS-Z0237. Tensilon UTM-4 (trade name, manufactured by Toyo Baldwin Co., Ltd., peel strength: 50 mm / min, 25 ° C.) was used as an adhesive strength measuring device. Table 2 shows the results.

  From Table 2, it was confirmed that the film adhesive of the example can obtain a higher adhesive strength (8 N / cm or more) even when connected with a width of 1.0 mm than the film adhesive of the comparative example. In the case of the film adhesive of Comparative Example 1, high adhesive strength was obtained at the time of connection of 1.5 mm width, but sufficient adhesive strength was not obtained at the time of connection of 1.0 mm width. In the case of the film adhesives of Comparative Examples 2 to 4, sufficient adhesive strength was not obtained even at the time of 1.5 mm width connection.

  DESCRIPTION OF SYMBOLS 10 ... Circuit connecting member, 10a ... Insulating substance, 10b ... Conductive particle, 20 ... First circuit member, 21 ... First board, 21a ... Main surface, 22 ... First circuit electrode, 30 ... Second Circuit member, 31: second substrate, 31a: main surface, 32: second circuit electrode, 100a, 100b: circuit connection structure.

Claims (6)

(A) a thermoplastic resin having a urethane bond;
(B) a radical polymerizable compound;
(C) a radical polymerization initiator;
(D) polyurethane beads,
(E) non-conductive inorganic fine particles;
An adhesive composition comprising:   The adhesive composition according to claim 1, wherein the content of the (a) thermoplastic resin having a urethane bond is equal to or greater than the content of the (d) polyurethane beads on a mass basis.   The adhesive composition according to claim 1, further comprising (f) conductive particles.   The adhesive composition according to any one of claims 1 to 3, which is used for circuit connection.   A structure comprising the adhesive composition according to claim 1 or a cured product thereof. A first circuit member having a first circuit electrode,
A second circuit member having a second circuit electrode,
A circuit connecting member disposed between the first circuit member and the second circuit member,
The first circuit electrode and the second circuit electrode are electrically connected,
A structure, wherein the circuit connection member includes the adhesive composition according to any one of claims 1 to 4 or a cured product thereof.

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