JP2012021114A - Curable composition and connection structure - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a curable composition quickly curable and capable of increasing adhesive force of the cured product to a connection object member, and to provide a connection structure produced by using the curable composition.SOLUTION: The curable composition includes a curable compound having a thiirane group, a thermosetting agent and a phenoxy resin having a weight-average molecular weight of ≥5,000. The connection structure 1 is provided with a first connection object member 2, a second connection object member 4 and a connection part 3 connecting the first and second connection object members 2, 4. The connection part 3 is made of the curable composition.

Description

  The present invention relates to a curable composition, and more particularly to a curable composition containing a curable compound having a thiirane group as a thermosetting compound, and a connection structure using the curable composition.

  The epoxy resin composition has high adhesive strength of the cured product after curing, and is excellent in water resistance and heat resistance of the cured product. For this reason, epoxy resin compositions are widely used in various applications such as electricity, electronics, architecture, and vehicles.

  Moreover, in order to electrically connect various connection object members, conductive particles may be blended in the epoxy resin composition. The epoxy resin composition containing conductive particles is called an anisotropic conductive material.

  Specifically, the anisotropic conductive material is used for connection between an IC chip and a flexible printed circuit board, connection between an IC chip and a circuit board having an ITO electrode, and the like. For example, after an anisotropic conductive material is arranged between the electrode of the IC chip and the electrode of the circuit board, these electrodes can be connected by heating and pressurizing.

  As an example of the anisotropic conductive material, Patent Document 1 below discloses a curing agent that generates free radicals upon heating, a hydroxyl group-containing resin having a molecular weight of 10,000 or more, a phosphate ester, a radical polymerizable substance, a conductive material. An anisotropic conductive material containing conductive particles is disclosed. Specific examples of the hydroxyl group-containing resin include polymers such as polyvinyl butyral resin, polyvinyl formal, polyamide, polyester, phenol resin, epoxy resin, and phenoxy resin.

  Patent Document 2 below discloses an anisotropic conductive material containing a curable component, a silane compound, and conductive particles. Here, it is described that a sufficient adhesive strength can be obtained by the combined use of the curable component and the silane compound, and a stable adhesive strength can be obtained even in a high temperature and high humidity environment.

JP 2005-314696 A JP 2006-16580 A

  In recent years, in the field of precision electronic equipment, the density of circuits has been increasing, and the electrode width and electrode interval have become extremely narrow. For this reason, in the conventional anisotropic conductive materials as described in Patent Documents 1 and 2, the curing does not proceed quickly, and the wiring may fall off, peel off, or be displaced.

  Moreover, although patent document 2 describes that sufficient adhesive strength is obtained, the problem that the adhesive strength of the cured | curing material of anisotropic conductive material with respect to adhesion target members, such as various board | substrates, does not necessarily become high enough. There is.

  An object of the present invention is to provide a curable composition that can be quickly cured and that can further increase the adhesive strength of a cured product to a connection target member, and a connection structure using the curable composition. That is.

  According to a wide aspect of the present invention, there is provided a curable composition comprising a curable compound having a thiirane group, a thermosetting agent, and a phenoxy resin having a weight average molecular weight of 5000 or more.

  In another specific aspect of the curable composition according to the present invention, conductive particles are further included, and the curable composition is an anisotropic conductive material.

  The connection structure according to the present invention includes a first connection target member, a second connection target member, and a connection portion connecting the first and second connection target members, and the connection The part is formed by a curable composition constituted according to the present invention.

  In a specific aspect of the connection structure according to the present invention, the curable composition is an anisotropic conductive material including conductive particles, and the first and second connection target members are the conductive particles. Are electrically connected.

  Since the curable composition concerning this invention contains the curable compound which has a thiirane group, a thermosetting agent, and a phenoxy resin, it can be hardened rapidly. Furthermore, the hardened | cured material which hardened the curable composition concerning this invention has high adhesive force with respect to a connection object member. Therefore, by using the curable composition according to the present invention, a connection structure having excellent connection reliability can be obtained.

FIG. 1 is a partially cutaway cross-sectional view schematically showing a connection structure using a curable composition according to an embodiment of the present invention.

  Hereinafter, the present invention will be described in detail.

(Curable composition)
The curable composition according to the present invention includes a curable compound having a thiirane group, a thermosetting agent, and a phenoxy resin having a weight average molecular weight of 5000 or more. By adopting this composition, the curable composition can be quickly cured at a low temperature, and the adhesive force of the cured product to the connection target member can be increased. Moreover, the adhesive force of the hardened | cured material which hardened the resin component of the curable composition with respect to metals, such as a metal wiring or electroconductive particle, becomes high by use of the curable composition which has the said composition. This is considered to be because the sulfur atom of the thiirane group of the curable compound having a thiirane group is coordinated with the metal.

  Conventionally, it has been difficult to achieve both low-temperature curing characteristics and adhesive strength at a high level. The inventor has found for the first time that the low-temperature curing characteristics and the adhesive strength can be achieved at a high level by employing the above composition.

  In recent years, in the field of precision electronic equipment, the density of circuits has been increasing, and the electrode width and electrode interval have become extremely narrow. For this reason, there is a high tendency for the wiring to drop off, peel off and be displaced. When the curable composition according to the present invention is an anisotropic conductive material containing conductive particles, the curable composition can be quickly cured at a low temperature and the cured product has high adhesive strength, so that the wiring Can be effectively prevented from falling off, peeling off and displacement. Therefore, the curable composition according to the present invention is particularly advantageous when it is an anisotropic conductive material containing conductive particles.

  Hereinafter, first, the detail of each component contained in the curable composition which concerns on this invention is demonstrated.

[Thermosetting compound]
The curable composition concerning this invention contains the curable compound which has a thiirane group as a thermosetting compound. The curable compound having a thiirane group is a thermosetting compound. As for the curable compound which has a thiirane group, only 1 type may be used and 2 or more types may be used together.

  The curable compound having a thiirane group may have an epoxy group. That is, the curable compound having a thiirane group may be a curable compound having a thiirane group and an epoxy group.

  The curable composition according to the present invention may contain a curable compound having an epoxy group different from the curable compound having a thiirane group, in addition to the curable compound having a thiirane group. That is, the curable composition according to the present invention may contain a curable compound having no thiirane group and having an epoxy group in addition to the curable compound having a thiirane group. The curable compound having an epoxy group is a thermosetting compound. As for the curable compound which has an epoxy group, only 1 type may be used and 2 or more types may be used together.

  When the curable compound having a thiirane group is a curable compound having a thiirane group and an epoxy group, the curable composition according to the present invention, in addition to the curable compound having a thiirane group and an epoxy group, The curable compound having an epoxy group different from the curable compound having a thiirane group and an epoxy group may be included, that is, a curable compound having no thiirane group and having an epoxy group may be included. Good.

  The curable compound having a thiirane group is an episulfide compound. The curable compound having an epoxy group is an epoxy compound. The curable compound having an epoxy group and a thiirane group is a thiirane group-containing epoxy compound.

  By using a curable compound having a thiirane group, the curable composition can be rapidly cured at a low temperature. From the viewpoint of enhancing the storage stability and handleability of the curable composition, the curable composition preferably contains a curable compound having a thiirane group and a curable compound having an epoxy group.

  In 100% by weight of the thermosetting compound, the content of the curable compound having a thiirane group is preferably in the range of 0.1 to 100% by weight. In 100% by weight of the thermosetting compound, the content of the curable compound having a thiirane group is more preferably 5% by weight or more, still more preferably 10% by weight or more, and particularly preferably 50% by weight or more. Since the curable compound having a thiirane group has a thiirane group, the reactivity is higher than that of the curable compound having an epoxy group. Therefore, the higher the content of the curable compound having a thiirane group, the more rapidly the curable composition can be cured at a low temperature.

  When only the curable compound having a thiirane group is used as the thermosetting compound, the “thermosetting compound 100 wt%” indicates 100 wt% of the curable compound having a thiirane group. When the curable compound having a thiirane group and the curable compound having an epoxy group are used in combination as the thermosetting compound, the “thermosetting compound 100% by weight” means the curable compound having a thiirane group and an epoxy. A total of 100% by weight with the curable compound having a group is shown.

  From the viewpoint of curing more rapidly at a low temperature, the curable compound having a thiirane group is represented by the following formula (1-1), (2-1), (3), (7) or (8). An episulfide compound having a structure is preferable, and an episulfide compound having a structure represented by the following formula (1-1), (2-1) or (3) is more preferable.

  In the following formula (1-1), the bonding sites of the six groups bonded to the benzene ring are not particularly limited. In the following formula (2-1), the bonding sites of the eight groups bonded to the naphthalene ring are not particularly limited.

  In said formula (1-1), R1 and R2 represent a C1-C5 alkylene group, respectively. Of the four groups R3, R4, R5 and R6, 2 to 4 groups represent hydrogen. The group which is not hydrogen among R3, R4, R5 and R6 represents a group represented by the following formula (4). All four groups of R3, R4, R5 and R6 may be hydrogen. One or two of the four groups of R3, R4, R5 and R6 is a group represented by the following formula (4), and among the four groups of R3, R4, R5 and R6 The group that is not a group represented by the following formula (4) may be hydrogen.

  In said formula (4), R7 represents a C1-C5 alkylene group.

  In said formula (2-1), R51 and R52 represent a C1-C5 alkylene group, respectively. Of the 6 groups of R53, R54, R55, R56, R57 and R58, 4 to 6 groups represent hydrogen. The group which is not hydrogen among R53, R54, R55, R56, R57 and R58 represents a group represented by the following formula (5). All of the six groups of R53, R54, R55, R56, R57 and R58 may be hydrogen. One or two of the six groups of R53, R54, R55, R56, R57 and R58 are groups represented by the following formula (5), and R53, R54, R55, R56, R57 and R58. Of these, a group that is not a group represented by the following formula (5) may be hydrogen.

  In said formula (5), R59 represents a C1-C5 alkylene group.

  In said formula (3), R101 and R102 represent a C1-C5 alkylene group, respectively. Six to eight groups out of the eight groups of R103, R104, R105, R106, R107, R108, R109 and R110 represent hydrogen. The group which is not hydrogen among R103, R104, R105, R106, R107, R108, R109 and R110 represents a group represented by the following formula (6). All of the eight groups of R103, R104, R105, R106, R107, R108, R109 and R110 may be hydrogen. One or two of the eight groups of R103, R104, R105, R106, R107, R108, R109 and R110 are groups represented by the following formula (6), and R103, R104, R105, R106 , R107, R108, R109 and R110, which is not a group represented by the following formula (6), may be hydrogen.

  In said formula (6), R111 represents a C1-C5 alkylene group.

  In said formula (7), R1 and R2 represent a C1-C5 alkylene group, respectively.

  In said formula (8), R3 and R4 represent a C1-C5 alkylene group, respectively.

  The curable compound having an epoxy group is not particularly limited. A conventionally well-known epoxy compound can be used as a curable compound which has an epoxy group. As for the said curable compound which has an epoxy group, only 1 type may be used and 2 or more types may be used together.

  Examples of the curable compound having an epoxy group include bisphenol F type epoxy resin, bisphenol S type epoxy resin, phenol novolac type epoxy resin, biphenol type epoxy resin, naphthalene type epoxy resin, fluorene type epoxy resin, phenol aralkyl type epoxy resin, Examples thereof include naphthol aralkyl type epoxy resins, dicyclopentadiene type epoxy resins, anthracene type epoxy resins, epoxy resins having an adamantane skeleton, epoxy resins having a tricyclodecane skeleton, and epoxy resins having a triazine nucleus in the skeleton.

  Furthermore, as the curable compound having the epoxy group, for example, an epoxy obtained by converting a thiirane group in the formula (1-1), (2-1), (3), (7) or (8) into an epoxy group. Compounds can be used.

  Furthermore, in the curable composition according to the present invention, as the curable compound having an epoxy group, an epoxy compound monomer having a structure represented by the following formula (21) and at least two of the epoxy compounds are bonded. A multimer, or a mixture of the monomer and the multimer.

  In said formula (21), R1 represents a C1-C5 alkylene group, R2 represents a C1-C5 alkylene group, R3 is a hydrogen atom, a C1-C5 alkyl group, or following formula ( 22), R4 represents a hydrogen atom, an alkyl group having 1 to 5 carbon atoms, or a structure represented by the following formula (23).

  In said formula (22), R5 represents a C1-C5 alkylene group.

  In said formula (23), R6 represents a C1-C5 alkylene group.

  The epoxy compound having the structure represented by the above formula (21) has an unsaturated double bond and at least two epoxy groups. By using the epoxy compound having the structure represented by the above formula (21), the curable composition can be rapidly cured at a low temperature.

  The curable composition according to the present invention includes a monomer of a compound having a structure represented by the following formula (31) as the curable compound having the thiirane group or the curable compound having the epoxy group, It may contain a multimer in which at least two are combined, or a mixture of the monomer and the multimer.

  In the above formula (31), R1 represents a hydrogen atom, an alkyl group having 1 to 5 carbon atoms or a structure represented by the following formula (32), R2 represents an alkylene group having 1 to 5 carbon atoms, and R3 represents carbon. X 1 represents an oxygen atom or a sulfur atom, and X 2 represents an oxygen atom or a sulfur atom.

  In said formula (32), R4 represents a C1-C5 alkylene group, X3 represents an oxygen atom or a sulfur atom.

  The curable composition concerning this invention may contain the epoxy compound which has a heterocyclic ring containing a nitrogen atom as a curable compound which has the said epoxy group. The epoxy compound having a heterocyclic ring containing a nitrogen atom is preferably an epoxy compound represented by the following formula (41) or an epoxy compound represented by the following formula (42). By using such a compound, the curing rate of the curable composition can be further increased, and the heat resistance of the cured product can be further enhanced.

  In said formula (41), R1-R3 represents a C1-C5 alkylene group, respectively, Z represents an epoxy group or a hydroxymethyl group. R1 to R3 may be the same or different.

  In the above formula (42), R1 to R3 each represent an alkylene group having 1 to 5 carbon atoms, p, q and r each represents an integer of 1 to 5, and R4 to R6 each represent an alkylene having 1 to 5 carbon atoms. Represents a group. R1 to R3 may be the same or different. p, q and r may be the same or different. R4-6 may be the same or different.

  The epoxy compound having a heterocyclic ring containing a nitrogen atom is preferably triglycidyl isocyanurate or trishydroxyethyl isocyanurate triglycidyl ether. By using these compounds, the curing rate of the curable composition can be further increased.

  It is preferable that the curable composition which concerns on this invention contains the epoxy compound which has an aromatic ring as a curable compound which has the said epoxy group. By using an epoxy compound having an aromatic ring, the curing rate of the curable composition can be further increased and the curable composition can be easily applied. From the viewpoint of further improving the applicability of the curable composition, the aromatic ring is preferably a benzene ring, a naphthalene ring or an anthracene ring. Examples of the epoxy compound having an aromatic ring include resorcinol diglycidyl ether and 1,6-naphthalenediglycidyl ether. Of these, resorcinol diglycidyl ether is particularly preferable. By using resorcinol diglycidyl ether, the curing rate of the curable composition can be increased and the curable composition can be easily applied.

[Phenoxy resin]
The phenoxy resin contained in the curable composition according to the present invention is not particularly limited. As the phenoxy resin, a conventionally known phenoxy resin can be used. As for a phenoxy resin, only 1 type may be used and 2 or more types may be used together.

  Specifically, the phenoxy resin is, for example, a resin obtained by reacting an epihalohydrin and a divalent phenol compound, or a resin obtained by reacting a divalent epoxy compound and a divalent phenol compound.

  The weight average molecular weight of the phenoxy resin is generally 5000 or more. Moreover, the weight average molecular weight of the phenoxy resin contained in the curable composition concerning this invention is 5000 or more. The phenoxy resin is superior in compatibility with other components as compared with a general epoxy resin. Moreover, the adhesiveness of the hardened | cured material of the curable composition using a phenoxy resin is comparatively high. Moreover, the larger the weight average molecular weight of the phenoxy resin, the easier it is to make the curable composition into a film, and the melt viscosity that affects the fluidity of the curable composition can be controlled over a wide range. Therefore, the weight average molecular weight of the phenoxy resin is preferably 10,000 or more. The upper limit of the weight average molecular weight of the phenoxy resin is not particularly limited. The weight average molecular weight of the phenoxy resin is preferably 1000000 or less, more preferably 250,000 or less.

  When the phenoxy resin has a polar group such as a hydroxy group or a carboxyl group, compatibility with other components, particularly a curable compound having an epoxy group, is increased. For this reason, the appearance of the cured product can be made uniform, and the curing rate of the curable composition can be further increased.

  The content of the phenoxy resin is preferably 10 parts by weight or more, more preferably 20 parts by weight or more, preferably 1000 parts by weight or less, more preferably 800 parts by weight with respect to 100 parts by weight of the curable compound having a thiirane group. Or less. The adhesive force with respect to the connection object member of hardened | cured material becomes still higher that content of a phenoxy resin is more than the said minimum. When the content of the phenoxy resin is not more than the above upper limit, the content of the curable compound having a thiirane group is relatively increased, and the curable composition can be effectively cured at a low temperature.

[Thermosetting agent]
The thermosetting agent contained in the curable composition according to the present invention is not particularly limited. The thermosetting agent cures the thermosetting compound. A conventionally known thermosetting agent can be used as the thermosetting agent. As for this thermosetting agent, only 1 type may be used and 2 or more types may be used together.

  Examples of the thermosetting agent include imidazole curing agents, amine curing agents, phenol curing agents, polythiol curing agents, and acid anhydrides. Especially, since a curable composition can be hardened more rapidly at low temperature, an imidazole hardening | curing agent, a polythiol hardening | curing agent, or an amine hardening | curing agent is preferable. Moreover, since a storage stability can be improved when the said thermosetting compound and the said thermosetting agent are mixed, a latent hardening agent is preferable. The latent curing agent is preferably a latent imidazole curing agent, a latent polythiol curing agent or a latent amine curing agent. As for these thermosetting agents, only 1 type may be used and 2 or more types may be used together. In addition, the said thermosetting agent may be coat | covered with polymeric substances, such as a polyurethane resin or a polyester resin.

  The imidazole curing agent is not particularly limited, but 2-methylimidazole, 2-ethyl-4-methylimidazole, 1-cyanoethyl-2-phenylimidazole, 1-cyanoethyl-2-phenylimidazolium trimellitate, 2, 4-Diamino-6- [2'-methylimidazolyl- (1 ')]-ethyl-s-triazine and 2,4-diamino-6- [2'-methylimidazolyl- (1')]-ethyl-s- Examples include triazine isocyanuric acid adducts.

  The polythiol curing agent is not particularly limited, and examples thereof include trimethylolpropane tris-3-mercaptopropionate, pentaerythritol tetrakis-3-mercaptopropionate, and dipentaerythritol hexa-3-mercaptopropionate. .

  Although it does not specifically limit as said amine hardening | curing agent, Hexamethylene diamine, octamethylene diamine, decamethylene diamine, 3,9-bis (3-aminopropyl) 2,4,8,10-tetraspiro [5.5] undecane , Bis (4-aminocyclohexyl) methane, metaphenylenediamine, diaminodiphenylsulfone and the like.

  Among the thermosetting agents, polythiol compounds or acid anhydrides are preferably used. Since the curing rate of the curable composition can be further increased, a polythiol compound is more preferably used.

  Among the polythiol compounds, pentaerythritol tetrakis-3-mercaptopropionate is more preferable. By using this polythiol compound, the curing rate of the curable composition can be further increased.

  The content of the thermosetting agent is not particularly limited. The content of the thermosetting agent is preferably 0.01 parts by weight or more, more preferably 30 parts by weight or more, still more preferably 45 parts by weight or more, preferably 200 parts by weight with respect to 100 parts by weight of the thermosetting compound. The amount is more preferably 100 parts by weight or less, still more preferably 75 parts by weight or less. It is easy to fully harden a curable composition as content of a thermosetting agent is more than the said minimum. When the content of the thermosetting agent is not more than the above upper limit, it is difficult for an excessive thermosetting agent that has not been involved in curing after curing to remain, and the heat resistance of the cured product can be further enhanced.

  When the thermosetting agent is an imidazole curing agent or a phenol curing agent, the content of the imidazole curing agent or the phenol curing agent is preferably 1 part by weight or more, preferably 100 parts by weight of the thermosetting compound. 15 parts by weight or less. Further, when the thermosetting agent is an amine curing agent, a polythiol curing agent or an acid anhydride, the content of the amine curing agent, polythiol curing agent or acid anhydride is preferably 100 parts by weight of the thermosetting compound. Is 15 parts by weight or more, preferably 40 parts by weight or less.

[Other ingredients]
The curable composition according to the present invention preferably further contains a curing accelerator. By using a curing accelerator, the curing rate of the curable composition can be further increased. As for a hardening accelerator, only 1 type may be used and 2 or more types may be used together.

  Specific examples of the curing accelerator include imidazole curing accelerators and amine curing accelerators. Of these, imidazole curing accelerators are preferred. In addition, an imidazole hardening accelerator or an amine hardening accelerator can be used also as an imidazole hardening agent or an amine hardening agent.

  Examples of the imidazole curing accelerator include 2-methylimidazole, 2-ethyl-4-methylimidazole, 1-cyanoethyl-2-phenylimidazole, 1-cyanoethyl-2-phenylimidazolium trimellitate, 2,4-diamino- 6- [2′-Methylimidazolyl- (1 ′)]-ethyl-s-triazine and 2,4-diamino-6- [2′-methylimidazolyl- (1 ′)]-ethyl-s-triazine isocyanuric acid addition Thing etc. are mentioned.

  The content of the curing accelerator is preferably 0.5 parts by weight or more, more preferably 1 part by weight or more, preferably 6 parts by weight or less, more preferably 4 parts by weight with respect to 100 parts by weight of the thermosetting compound. It is as follows. It is easy to fully harden a curable composition as content of a hardening accelerator is more than the said minimum. When the content of the curing accelerator is less than or equal to the above upper limit, it is difficult for an excessive curing accelerator that did not participate in curing after curing to remain.

  The curable composition concerning this invention may further contain the photocurable compound so that it may harden | cure also by light irradiation. Moreover, when a photocurable compound is contained, the curable composition concerning this invention may further contain the photoinitiator. However, when using the curable composition concerning this invention, you may add a photoinitiator to this curable composition. By using the photocurable compound and the photopolymerization initiator, the curable composition can be cured by light irradiation. Furthermore, the curable composition can be semi-cured to reduce the fluidity of the curable composition.

  The said photocurable compound is not specifically limited. As the photocurable compound, a (meth) acrylic resin or a cyclic ether group-containing resin is preferably used, and a (meth) acrylic resin is more preferably used. The (meth) acrylic resin indicates a methacrylic resin and an acrylic resin. The (meth) acrylic resin has a (meth) acryloyl group. The (meth) acryloyl group represents a methacryloyl group and an acryloyl group.

  In the composition containing the thermosetting compound and the (meth) acrylic resin, when the epoxy group or thiirane group of the thermosetting compound is ring-opened to generate a radical, a (meth) acrylic is produced by the action of the radical. Resin polymerization is likely to proceed. However, when the phenolic compound and the storage stabilizer are combined with the thermosetting compound, the epoxy group or thiirane group is difficult to open during storage of the curable composition. As a result, polymerization of the (meth) acrylic resin is difficult to proceed during storage of the curable composition.

  As the (meth) acrylic resin, an ester compound obtained by reacting (meth) acrylic acid and a compound having a hydroxyl group, an epoxy (meth) acrylate obtained by reacting (meth) acrylic acid and an epoxy compound, or Urethane (meth) acrylate obtained by reacting a (meth) acrylic acid derivative having a hydroxyl group with isocyanate is preferably used.

  The ester compound obtained by making the said (meth) acrylic acid and the compound which has a hydroxyl group react is not specifically limited. As the ester compound, any of a monofunctional ester compound, a bifunctional ester compound, and a trifunctional or higher functional ester compound can be used.

  The photocurable compound preferably includes light having at least one kind of epoxy group and a (meth) acryl group and a thermosetting compound (hereinafter also referred to as a partially (meth) acrylated epoxy resin).

  The partially (meth) acrylated epoxy resin can be obtained, for example, by reacting an epoxy resin and (meth) acrylic acid in the presence of a basic catalyst according to a conventional method. It is preferable that 20% or more of the epoxy groups are converted to (meth) acryloyl groups (conversion rate) and partially (meth) acrylated. More preferably, 50% of the epoxy groups are converted to (meth) acryloyl groups.

  Examples of the epoxy (meth) acrylate include bisphenol type epoxy (meth) acrylate, cresol novolac type epoxy (meth) acrylate, carboxylic acid anhydride-modified epoxy (meth) acrylate, and phenol novolac type epoxy (meth) acrylate. .

  When a photocurable compound other than the photocurable compounds described above is included, the photocurable compound may be a crosslinkable compound or a non-crosslinkable compound.

  Specific examples of the crosslinkable compound include 1,4-butanediol di (meth) acrylate, 1,6-hexanediol di (meth) acrylate, 1,9-nonanediol di (meth) acrylate, (poly ) Ethylene glycol di (meth) acrylate, (poly) propylene glycol di (meth) acrylate, neopentyl glycol di (meth) acrylate, pentaerythritol di (meth) acrylate, glycerol methacrylate acrylate, pentaerythritol tri (meth) acrylate, tri Examples include methylolpropane trimethacrylate, allyl (meth) acrylate, vinyl (meth) acrylate, divinylbenzene, polyester (meth) acrylate, and urethane (meth) acrylate.

  Specific examples of the non-crosslinkable compound include ethyl (meth) acrylate, n-propyl (meth) acrylate, isopropyl (meth) acrylate, n-butyl (meth) acrylate, isobutyl (meth) acrylate, t-butyl (meth) ) Acrylate, pentyl (meth) acrylate, hexyl (meth) acrylate, heptyl (meth) acrylate, 2-ethylhexyl (meth) acrylate, n-octyl (meth) acrylate, isooctyl (meth) acrylate, nonyl (meth) acrylate, decyl Examples include (meth) acrylate, undecyl (meth) acrylate, dodecyl (meth) acrylate, tridecyl (meth) acrylate, and tetradecyl (meth) acrylate.

  From the viewpoint of efficiently photocuring the curable composition, the photocurable compound (when the photocurable compound is a (meth) acrylic resin with respect to 100 parts by weight of the thermosetting compound ( The content of (meth) acrylic resin) is preferably 0.1 parts by weight or more, more preferably 1 part by weight or more, still more preferably 10 parts by weight or more, particularly preferably 50 parts by weight or more, preferably 10,000 parts by weight or less. More preferably, it is 1000 weight part or less, More preferably, it is 500 weight part or less.

  The photopolymerization initiator is not particularly limited. As for the said photoinitiator, only 1 type may be used and 2 or more types may be used together.

  Specific examples of the photopolymerization initiator include acetophenone photopolymerization initiator, benzophenone photopolymerization initiator, thioxanthone, ketal photopolymerization initiator, halogenated ketone, acyl phosphinoxide, and acyl phosphonate.

  Specific examples of the acetophenone photopolymerization initiator include 4- (2-hydroxyethoxy) phenyl (2-hydroxy-2-propyl) ketone, 2-hydroxy-2-methyl-1-phenylpropan-1-one, methoxy Examples include acetophenone, 2,2-dimethoxy-1,2-diphenylethane-1-one, and 2-hydroxy-2-cyclohexylacetophenone. Specific examples of the ketal photopolymerization initiator include benzyl dimethyl ketal.

  The content of the photopolymerization initiator is not particularly limited. The content of the photopolymerization initiator is preferably 0.1 parts by weight or more, more preferably 0.2 parts by weight or more, still more preferably 2 parts by weight or more, based on 100 parts by weight of the photocurable compound. Is 10 parts by weight or less, more preferably 5 parts by weight or less. When the content of the photopolymerization initiator is not less than the above lower limit, it is easy to sufficiently obtain the effect of adding the photopolymerization initiator. When the content of the photopolymerization initiator is not more than the above upper limit, the adhesive strength of the cured product of the curable composition is sufficiently increased.

  The curable composition according to the present invention preferably further contains a phenolic compound. By using a curable compound having a thiirane group, a thermosetting agent, a phenoxy resin, and a phenolic compound, a curable composition containing conductive particles was placed between the electrodes to appropriately compress the conductive particles. Sometimes an appropriate impression can be formed on the electrode. Therefore, the connection resistance between the electrodes can be lowered.

  The phenolic compound has a phenolic hydroxyl group in which a hydroxyl group is bonded to a benzene ring. Examples of the phenolic compound include polyphenol, triol, hydroquinone, and tocopherol (vitamin E). As for the said phenolic compound, only 1 type may be used and 2 or more types may be used together.

  The curable composition according to the present invention preferably further contains a filler. By using the filler, latent heat expansion of the cured product of the curable composition can be suppressed. As for a filler, only 1 type may be used and 2 or more types may be used together.

  Specific examples of the filler include silica, aluminum nitride, and alumina. The filler is preferably filler particles.

  The curable composition according to the present invention may contain a solvent. By using the solvent, the viscosity of the curable composition can be easily adjusted. Furthermore, for example, when the thermosetting compound is solid, the dispersibility of the thermosetting compound can be improved by adding a solvent to the solid thermosetting compound and dissolving it.

  Examples of the solvent include ethyl acetate, methyl cellosolve, toluene, acetone, methyl ethyl ketone, cyclohexane, n-hexane, tetrahydrofuran, and diethyl ether.

  The curable composition according to the present invention preferably further contains a storage stabilizer. The curable composition according to the present invention preferably contains at least one selected from the group consisting of phosphate ester, phosphite ester and borate ester as the storage stabilizer, and phosphate ester and phosphorous acid. It is more preferable to include at least one of the esters, and it is even more preferable to include a phosphite. By using these storage stabilizers, particularly by using phosphites, the storage stability of the curable compound having a thiirane group can be further enhanced. As for the said storage stabilizer, only 1 type may be used and 2 or more types may be used together.

  Examples of the phosphate ester include diethyl benzyl phosphate. As the phosphite, diphenyl mono (2-ethylhexyl) phosphite, diphenyl monodecyl phosphite or diphenyl mono (tridecyl) phosphite is preferable, and diphenyl monodecyl phosphite and diphenyl mono (tridecyl) phosphite are listed. It is done.

  The curable composition according to the present invention is at least one component selected from the group consisting of ascorbic acid, a derivative of ascorbic acid, a salt of ascorbic acid, isoascorbic acid, a derivative of isoascorbic acid, and a salt of isoascorbic acid May be included. By blending these components, the storage stability of the curable composition is increased.

  The curable composition concerning this invention may further contain the ion-trapping agent or the silane coupling agent as needed.

[Curable composition containing conductive particles]
When the curable composition according to the present invention further contains conductive particles, the curable composition can be used as an anisotropic conductive material. Since the curable composition according to the present invention includes a curable compound having a thiirane group, a thermosetting agent, and a phenoxy resin, the adhesive force between the cured product of the resin component of the curable composition and the conductive particles is increased. be able to.

  For example, the conductive particles electrically connect the electrodes of the circuit board and the semiconductor chip. The conductive particles are not particularly limited as long as at least the surface has conductivity. Examples of the conductive particles include conductive particles whose surfaces are coated with a metal layer, such as organic particles, inorganic particles, organic-inorganic hybrid particles, or metal particles, or metal particles that are substantially composed of only metal. It is done. The metal layer is not particularly limited. Examples of the metal layer include a gold layer, a silver layer, a copper layer, a nickel layer, a palladium layer, or a metal layer containing tin. The conductive particles may be conductive particles whose surface is covered with solder.

  The content of the conductive particles is not particularly limited. In 100% by weight of the curable composition, the content of the conductive particles is preferably 0.1% by weight or more, more preferably 0.5% by weight or more, preferably 20% by weight or less, more preferably 10% by weight. Hereinafter, it is further preferably 5% by weight or less. A conductive particle can be easily arrange | positioned between the upper and lower electrodes which should be connected as content of the said electroconductive particle is more than the said minimum and below the said upper limit. Furthermore, it becomes difficult to electrically connect adjacent electrodes that should not be connected via a plurality of conductive particles. That is, a short circuit between adjacent electrodes can be prevented.

(Use of curable composition)
The curable composition concerning this invention can be used for adhere | attaching various connection object members.

  When the curable composition according to the present invention is an anisotropic conductive material containing conductive particles, the anisotropic conductive material includes an anisotropic conductive paste, an anisotropic conductive ink, and an anisotropic conductive adhesive. It can be used as an adhesive, an anisotropic conductive film, or an anisotropic conductive sheet. When the anisotropic conductive material is used as a film-like adhesive such as an anisotropic conductive film or anisotropic conductive sheet, the film-like adhesive containing the conductive particles contains conductive particles. No film-like adhesive may be laminated.

  The anisotropic conductive material is suitably used for obtaining a connection structure in which the first and second connection target members are electrically connected.

  In FIG. 1, an example of the connection structure using the curable composition which concerns on one Embodiment of this invention is typically shown with sectional drawing.

  A connection structure 1 shown in FIG. 1 includes a first connection target member 2, a second connection target member 4, and a connection part 3 connecting the first and second connection target members 2 and 4. Prepare. The connection part 3 is formed by hardening the curable composition containing the electroconductive particle 5, ie, an anisotropic conductive material.

  A plurality of electrodes 2 b are provided on the upper surface 2 a of the first connection target member 2. A plurality of electrodes 4 b are provided on the lower surface 4 a of the second connection target member 4. The electrode 2b and the electrode 4b are electrically connected by one or a plurality of conductive particles 5. Therefore, the first and second connection target members 2 and 4 are electrically connected by the conductive particles 5.

  Specifically, as the connection structure, an electronic component chip such as a semiconductor chip, a capacitor chip or a diode chip is mounted on a circuit board, and the electrode of the electronic component chip is connected to an electrode on the circuit board. Examples include electrically connected structures. As a circuit board, various printed circuit boards, such as various printed circuit boards, such as a flexible printed circuit board, a glass substrate, or a board | substrate with which metal foil was laminated | stacked are mentioned. The first and second connection target members are preferably electronic components or circuit boards.

  The manufacturing method of the connection structure is not particularly limited. As an example of a manufacturing method of a connection structure, the anisotropic conductive material is disposed between a first connection target member such as an electronic component or a circuit board and a second connection target member such as an electronic component or a circuit board. And after obtaining a laminated body, the method etc. which heat and pressurize this laminated body are mentioned.

  In addition, the said curable composition does not need to contain electroconductive particle. In this case, the curable composition is used to bond and connect the first and second connection target members without electrically connecting the first and second connection target members.

  Hereinafter, the present invention will be specifically described with reference to Examples and Comparative Examples. The present invention is not limited only to the following examples.

  In order to obtain anisotropic conductive materials of Examples and Comparative Examples, the following materials were used.

(1) Preparation of a compound having a thiirane group In a 2 L vessel equipped with a stirrer, a cooler and a thermometer, ethanol 250 mL, pure water 250 mL, and potassium thiocyanate 20 g were added to dissolve potassium thiocyanate, A first solution was prepared. Thereafter, the temperature in the container was kept in the range of 20 to 25 ° C. Next, 160 g of resorcinol diglycidyl ether was dropped into the first solution at a rate of 5 mL / min while stirring the first solution in the container maintained at 20 to 25 ° C. After dropping, the mixture was further stirred for 30 minutes to obtain an epoxy compound-containing mixed solution.

  Next, a second solution in which 20 g of potassium thiocyanate was dissolved in a solution containing 100 mL of pure water and 100 mL of ethanol was prepared. The obtained second solution was added to the obtained epoxy group-containing mixed solution at a rate of 5 mL / min, and then stirred for 30 minutes. After stirring, a second solution in which 20 g of potassium thiocyanate is dissolved in a solution containing 100 mL of pure water and 100 mL of ethanol is further prepared, and the second solution is further added to the container at a rate of 5 mL / min. And stirred for 30 minutes. Thereafter, the temperature in the container was cooled to 10 ° C., and stirred for 2 hours to be reacted.

  Next, 100 mL of saturated saline was added to the container and stirred for 10 minutes. After stirring, 300 mL of toluene was further added to the container and stirred for 10 minutes. Thereafter, the solution in the container was transferred to a separating funnel and allowed to stand for 2 hours to separate the solution. The lower solution in the separatory funnel was discharged, and the supernatant was taken out. 100 mL of toluene was added to the removed supernatant, stirred, and allowed to stand for 2 hours. Further, 100 mL of toluene was further added, stirred and allowed to stand for 2 hours.

  Next, 50 g of magnesium sulfate was added to the supernatant liquid to which toluene was added and stirred for 5 minutes. After stirring, magnesium sulfate was removed with a filter paper to separate the solution. The remaining solvent was removed by drying the separated solution under reduced pressure at 80 ° C. using a vacuum dryer. Thus, a compound (mixture) 1 having a thiirane group was obtained.

(2) Compound having no thiirane group Epoxy resin (“EX-201P” manufactured by Nagase ChemteX Corporation)
Phenoxy resin (“YP-50S” manufactured by Nippon Steel Chemical Co., Ltd., Mw = 55000)
Urethane resin (“T-5201H” manufactured by DIC, 20% by weight solution of MEK (methyl ethyl ketone))
Acrylic resin (“G-2050M” manufactured by NOF Corporation)

(3) Thermosetting agent Thermosetting agent ("PN-23J" manufactured by Ajinomoto Fine Techno Co., Ltd.)

(4) Conductive particles Conductive particles (conductive particles having a metal layer in which a gold plating layer is formed on the surface of a nickel plating layer)

(Examples 1-2 and Comparative Examples 1-4)
The components shown in Table 1 below were uniformly mixed at a ratio shown in Table 1 below in terms of solid content to obtain a mixture.

  When the obtained mixture was a solvent-free liquid composition, the mixture was used as it was as a paste (anisotropic conductive paste).

  When the obtained mixture is a solvent-containing composition or a solid composition, the mixture is diluted with a solvent, applied on a fluorine-based film using a coating apparatus, and then dried to remove the solvent. To obtain a film (anisotropic conductive film).

(Evaluation)
(1) Low temperature curing characteristics A flexible circuit board (FPC) having 500 copper wiring patterns having a line width of 50 μm and a pitch of 100 μm and a glass substrate on which a thin layer of ITO was formed were prepared. On this glass substrate, the obtained paste was applied, or the obtained film was peeled off from the fluorine-based film and laminated to form a curable composition layer. Next, a flexible circuit board was laminated on the curable composition layer.

  Then, while adjusting the temperature of the heating head so that the temperature of the curable composition layer is 185 ° C., the heating head is placed on the upper surface of the flexible circuit board, and a pressure of 3 MPa is applied to 185 ° C. To obtain a connection structure. When obtaining this connection structure, the time until the curable composition layer was cured by heating was measured. The low temperature curing characteristics were determined according to the following criteria.

[Criteria for low-temperature curing characteristics]
◯: Curing time 5 seconds or less ○: Curing time exceeds 5 seconds, 10 seconds or less ×: Curing time 10 seconds or more

(2) Leak Evaluation Using the connection structure obtained in the above (1) evaluation of low temperature curing characteristics, whether or not there is a leak between adjacent electrodes is measured by a tester and determined by the following criteria did.

[Criteria for leak evaluation]
○: No leak ×: Leak generated −: Not evaluated

(3) Adhesive strength In the connection structure obtained by the evaluation of the above (1) low-temperature curing characteristics, the adhesive strength was measured by a 90-degree peeling method and evaluated. Adhesive strength (adhesive force) was determined according to the following criteria.

[Evaluation criteria for adhesive strength]
○: Adhesive force of 100 N / m or more ×: Adhesive force of less than 100 N / m −: Not evaluated

  The results are shown in Table 1 below.

DESCRIPTION OF SYMBOLS 1 ... Connection structure 2 ... 1st connection object member 2a ... Upper surface 2b ... Electrode 3 ... Connection part 4 ... 2nd connection object member 4a ... Lower surface 4b ... Electrode 5 ... Conductive particle

Claims (4)

  A curable composition comprising a curable compound having a thiirane group, a thermosetting agent, and a phenoxy resin having a weight average molecular weight of 5000 or more. Further comprising conductive particles;
The curable composition according to claim 1, which is an anisotropic conductive material. A first connection target member, a second connection target member, and a connection part connecting the first and second connection target members;
A connection structure in which the connection portion is formed of the curable composition according to claim 1. The curable composition is an anisotropic conductive material containing conductive particles,
The connection structure according to claim 3, wherein the first and second connection target members are electrically connected by the conductive particles.

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