JP2022151308A - Thermosetting adhesive composition and its cured product, and joined body - Google Patents

Abstract

To provide a thermosetting adhesive composition which can achieve both high curability and excellent storage stability.SOLUTION: A thermosetting adhesive composition contains (A) an epoxy resin, (B) a curing agent, and (C) a latent curing agent. The (B) curing agent contains (B1) secondary thiol. The (C) latent curing agent contains two or more latent curing agents having mutually different exothermic peak top temperatures by reaction of an epoxy resin and secondary thiol determined by differential scanning calorimetry at a rate of temperature rise of 10°C/min by 10°C or more. A molar ratio of a sulfanyl group of (B) the curing agent to an epoxy group of (A) the epoxy resin is 0.8 or more.SELECTED DRAWING: None

Description

TECHNICAL FIELD The present disclosure relates to a thermosetting adhesive composition, a cured product of this thermosetting adhesive composition, and a bonded article, and more specifically, a thermosetting adhesive composition containing an epoxy resin, a curing agent, and a latent curing agent. The present invention relates to a thermosetting adhesive composition, a cured product of this thermosetting adhesive composition, and a joined body produced using this thermosetting adhesive composition.

In electronic devices, thermosetting adhesive compositions used for bonding when manufacturing bonded bodies, such as assembly of modules such as camera modules and bonding to housings, are used for comparison at 80 ° C. for 60 minutes, for example. It is required that a high curing rate can be achieved at a relatively low temperature in a short period of time, thereby increasing the adhesion strength of the cured product to copper, liquid crystal polymer (LCP), and the like. Moreover, such a thermosetting adhesive composition is also required to have good storage stability. Thus, in order to achieve both good curability and storage stability, (a) an epoxy component, (b) a latent curing agent component, (c) a thixotropy imparting component, and (d) a secondary or tertiary A curable one-component epoxy resin composition containing a polythiol component containing a polythiol having a thiol group and (e) a stabilizing component containing a solid organic acid has been investigated (see Patent Document 1).

Japanese Patent Publication No. 2014-500895

Recently, however, the demand for curability and storage stability for thermosetting adhesive compositions has increased, and a high curing rate can be achieved at a lower temperature and in a shorter time, such as 60°C for 30 minutes. In addition to curability, there is a demand for excellent storage stability capable of suppressing degradation not only at room temperature, but also in relatively high temperature environments of about 45°C, such as during transportation in the summer. The conventional compositions described above have not been able to achieve both such high curability and excellent storage stability.

The subject of the present disclosure is a thermosetting adhesive composition capable of achieving both high curability and excellent storage stability, a cured product of this thermosetting adhesive composition, and this thermosetting adhesive composition. An object of the present invention is to provide a conjugate produced using a material.

A thermosetting adhesive composition according to one aspect of the present disclosure contains (A) an epoxy resin, (B) a curing agent, and (C) a latent curing agent. The (B) curing agent contains (B1) a secondary thiol. The (C) latent curing agent has two or more latent exothermic peak top temperatures different from each other by 10 ° C. or more in the reaction with the epoxy resin and the secondary thiol obtained by differential scanning calorimetry at a temperature increase rate of 10 ° C./min. Contains hardener. The molar ratio of the sulfanyl group of the curing agent (B) to the epoxy group of the epoxy resin (A) is 0.8 or more.

A cured product according to an aspect of the present disclosure is a cured product of the thermosetting adhesive composition.

A joined body according to an aspect of the present disclosure includes a first member, a second member, and a joining layer. The bonding layer is interposed between the first member and the second member to bond the first member and the second member. The bonding layer includes a cured product of the thermosetting adhesive composition.

According to the present disclosure, a thermosetting adhesive composition capable of achieving both high curability and excellent storage stability, a cured product of this thermosetting adhesive composition, and this thermosetting adhesive composition A conjugate made using the material can be provided.

1. Overview The thermosetting adhesive composition (hereinafter also referred to as composition (X)) according to the present embodiment contains (A) an epoxy resin, (B) a curing agent, and (C) a latent curing agent. do. (B) The curing agent contains (B1) a secondary thiol. (C) The latent curing agent is two or more latent curing agents whose exothermic peak top temperature of the reaction with the epoxy resin and the secondary thiol determined by differential scanning calorimetry at a temperature increase rate of 10 ° C./min differs from each other by 10 ° C. or more. containing agents. The molar ratio of the sulfanyl groups of the (B) curing agent to the epoxy groups of the (A) epoxy resin is 0.8 or more.

The inventors made intensive studies to solve the problem of achieving both a high curability that enables a high curing rate to be achieved at a relatively low temperature in a short time, and storage stability at room temperature and in a relatively high temperature environment. . As a result, in the thermosetting adhesive composition containing (A) an epoxy resin, in addition to using a secondary thiol as (B) a curing agent, (C) a latent curing agent having specific temperature characteristics By using a plurality of latent curing agents possessed, by more appropriately controlling the curing reaction during heat curing, it was found that both high curability and excellent storage stability can be achieved, and the present disclosure was completed. .

Although it is not necessarily clear why the composition (X) having the above structure exhibits the above effect, it can be inferred, for example, as follows. That is, as the latent curing agent (C), by using a plurality of substances whose exothermic peak temperatures differ from each other by a certain value or more, curing occurs stepwise during heat curing, so that the curing can be performed in a limited time. (A) Epoxy resin and (B) Curing agent can be efficiently reacted inside, and it is possible to greatly reduce the unreacted (A) Epoxy resin remaining after heat treatment, which is thought to improve curability. . Further, by using a secondary thiol having relatively low reactivity with (A) the epoxy resin as the (B) curing agent, the storage stability can be improved. By setting the molar ratio of the sulfanyl group of the curing agent (B) to the group to a specific value or more, it is believed that the amount of unreacted epoxy resin can be further reduced, thereby further improving the curability. As a result, the composition (X) can achieve both high curability and excellent storage stability. Moreover, due to this high curability, the cured product of composition (X) can exhibit high adhesive strength to copper, LCP, and the like.

2. Details <Thermosetting adhesive composition>
The composition (X) according to this embodiment contains (A) an epoxy resin, (B) a curing agent, and (C) a latent curing agent. Composition (X) preferably contains (D) a stabilizer, and contains (E) other components other than components (A) to (D) within a range that does not impair the effects of the present disclosure. may Each component will be described below.

[(A) epoxy resin]
(A) The epoxy resin is not particularly limited as long as it is a compound having one or more epoxy groups in one molecule. (A) Epoxy resins preferably include those having two or more epoxy groups in one molecule.

(A) Epoxy resins include, for example, bisphenol type epoxy resins such as bisphenol A type epoxy resins and bisphenol F type epoxy resins; hydrogenated bisphenol type epoxy resins such as hydrogenated bisphenol A type epoxy resins and hydrogenated bisphenol F type epoxy resins. ; biphenyl type epoxy resin, naphthalene ring-containing epoxy resin, alicyclic epoxy resin, dicyclopentadiene type epoxy resin, phenol novolak type epoxy resin, cresol novolak type epoxy resin, triphenylmethane type epoxy resin, aliphatic epoxy resin, triglycidyl isocyanurate, glycidyl group-containing silicone resin, glycidylamine type epoxy resin, and the like.

(A) The epoxy resin is preferably liquid at room temperature (25°C). By using an epoxy resin (A) that is liquid at room temperature, the viscosity of the composition (X) can be appropriately lowered, and as a result, the coatability can be further improved.

The ratio of (A) the epoxy resin to the entire composition (X) is preferably 10% by mass or more and 70% by mass or less. In this case, the curability and storage stability of composition (X) can be further improved. This proportion is more preferably 20% by mass or more and 60% by mass or less, and further preferably 30% by mass or more and 45% by mass or less.

[(B) Curing agent]
The (B) curing agent is a compound capable of undergoing a curing reaction with the (A) epoxy resin. (B) It is important that the curing agent contains (B1) a secondary thiol. “Secondary thiol” refers to a compound having at least one secondary sulfanyl group (—SH group) and no primary sulfanyl group. A "secondary sulfanyl group" refers to a sulfanyl group bonded to a secondary carbon atom. A "primary sulfanyl group" refers to a sulfanyl group bonded to a primary carbon atom.

(B1) Secondary thiols include monofunctional thiols such as 2-octanethiol, 2-decanethiol, cyclopentanethiol, cyclohexanethiol, and 3-mercaptohexyl acetate; 1,4-bis(3-mercaptobutyryloxy ) butane (commercial product: “Karenzu MT BD1” manufactured by Showa Denko), bifunctional thiols such as 2,7-octanedithiol; 1,3,5-tris(2-(3-mercaptobutyryloxy)ethyl) -1,3,5-triazine-2,4,6(1H,2H,5H)-trione (commercial product: "Karenzu MT NR1" manufactured by Showa Denko Co., Ltd.), trimethylolpropane tris (3-mercaptobutyrate) (commercially available: "Karenzu MT TPMB" manufactured by Showa Denko), etc.; trifunctional thiol; Thiol; hexafunctional thiol such as dipentaerythritol hexakis (3-mercaptobutyrate) and the like.

From the viewpoint of further improving the reactivity of the composition (X) and the glass transition temperature and strength of the cured product, the secondary thiol (B1) preferably contains a difunctional to hexafunctional polyfunctional thiol. More preferably it contains a functional thiol.

(B) The curing agent may contain (B2) primary thiol in addition to (B1) secondary thiol. "Primary thiol" refers to a compound having at least one primary sulfanyl group. When the (B) curing agent contains (B2) primary thiol, the curability of the composition (X) can be further improved. In addition, (B) the curing agent may contain (B3) a tertiary thiol in addition to the (B1) secondary thiol. "Tertiary thiol" refers to a compound having only a tertiary sulfanyl group as a sulfanyl group. A "tertiary sulfanyl group" refers to a sulfanyl group bonded to a tertiary carbon atom.

(B2) Primary thiols include, for example, 1-pentanethiol, 1-decanethiol, 1-dodecanethiol (commercially available product: "Thiocalcol 20" manufactured by Kao Corporation), 1-hexadecanethiol, 1-octadecanethiol, 2- Ethylhexyl-3-mercaptopropionate (commercial product: “EHMP” manufactured by SC Organic Chemical Co., Ltd.), n-octyl-3-mercaptopropionate (commercial product: “NOMP” manufactured by SC Organic Chemical Co., Ltd.), stearyl- Monofunctional thiols such as 3-mercaptopropionate (commercially available: “STMP” manufactured by SC Organic Chemical Co., Ltd.); tetraethylene glycol bis (3-mercaptopropionate) (commercially available: “DPMP” manufactured by SC Organic Chemical ”), bifunctional thiols such as 1,6-hexanediol bis (thioglycolate); Trifunctional thiols such as [(3-mercaptopropionyloxy) ethyl]-isocyanurate (commercially available: “TEMPIC” manufactured by SC Organic Chemical Co., Ltd.); pentaerythritol tetrakis (3-mercaptopropionate) (commercially available: SC organic Tetrafunctional thiol such as "PEMP" manufactured by Kagaku Co., Ltd.; .

(B) When the curing agent contains (B2) a primary thiol, from the viewpoint of further improving the reactivity of the composition (X) and the glass transition temperature and strength of the cured product, (B2) the primary thiol is 2 It preferably contains a polyfunctional thiol with ˜6 functionality, and more preferably contains a 4- to 6-functional thiol.

(B3) Tertiary thiols include, for example, t-butylthiol and 3-mercapto-3-methylbutanol.

(B) The curing agent may contain (B4) other curing agents other than (B1) secondary thiol, (B2) primary thiol, and (B3) tertiary thiol. (B4) Other curing agents include, for example, phenol-based curing agents such as phenol novolak resins; acid anhydrides, amines, imidazoles or salts thereof, hydrazides, polymercaptans, Lewis acid-amine complexes, and the like. be done.

The ratio of (B1) secondary thiol in (B) curing agent is preferably 50% by mass or more, more preferably 70% by mass or more, and even more preferably 90% by mass or more. (B1) The proportion of secondary thiol may be 100% by mass. In these cases, the storage stability of composition (X) can be further improved.

The ratio of the curing agent (B) to the entire composition (X) is preferably 10% by mass or more and 60% by mass or less, more preferably 20% by mass or more and 50% by mass or less, and 30% by mass or more and 40% by mass. % by mass or less is more preferable. In this case, the curability of composition (X) can be further improved.

It is important that the molar ratio of the sulfanyl groups of the curing agent (B) to the epoxy groups of the epoxy resin (A) (the number of moles of sulfanyl groups/the number of moles of epoxy groups) is 0.8 or more. This molar ratio is preferably 0.85 or more, more preferably 0.9 or more. The upper limit of this molar ratio is, for example, 1.2 or less, preferably 1.1 or less, more preferably 1.05 or less, and even more preferably 1.0 or less. In these cases, the curability and storage stability of composition (X) can be further improved. The sulfanyl group of the (B) curing agent means the sum of the secondary sulfanyl group, the primary sulfanyl group and the tertiary sulfanyl group of the (B) curing agent.

[(C) latent curing agent]
The term "latent curing agent" refers to a curing agent that does not exhibit curing properties in an epoxy resin under a room temperature environment, but exhibits curing properties due to an external stimulus such as heat or pressure. The (C) latent curing agent contained in the composition (X) develops curability when heated to a predetermined temperature or higher.

Composition (X) contains two or more latent curing agents as (C) latent curing agents, and it is important that the exothermic peak top temperatures of the two or more latent curing agents differ from each other by 10°C or more. is. (C) When the latent curing agent contains 3 or more latent curing agents, "the exothermic peak top temperatures differ from each other by 10 ° C. or more" means any two latent curing agents among the 3 or more latent curing agents. It means that the difference between the exothermic peak top temperatures of the curing agents is 10° C. or more.

When the temperature of the latent curing agent is raised by heating or the like, when a predetermined temperature is reached, the latent curing agent generates a curing agent and/or a catalyst, and the action of this curing agent and/or catalyst causes the epoxy resin and the secondary A reaction with the thiol occurs and the reaction generates an exotherm. This heat generation can be observed by differential scanning calorimetry (DSC), and the temperature at which the peak top of the exothermic peak in the obtained exothermic curve is maximized is called the "exothermic peak top temperature." Further, the temperature corresponding to the intersection of the tangent line at the point of inflection with the maximum slope at the rise of the exothermic peak of the exothermic curve and the baseline is called the "onset temperature".

The temperature that gives the DSC exothermic peak depends not only on the type of the latent curing agent, but also on the ratio of the latent curing agent in the DSC measurement sample, the type and ratio of the epoxy resin and the curing agent, and also on the rate of temperature increase in the DSC measurement. also change. In the present embodiment, the exothermic peak top temperature and the onset temperature are values determined by the measurement method and measurement conditions described in Examples below.

The difference in exothermic peak top temperature between the two or more latent curing agents is preferably 13°C or higher, more preferably 15°C or higher, even more preferably 18°C or higher, and 30°C or higher. is particularly preferred, 50° C. or higher is even more preferred, and 80° C. or higher is most preferred. In this case, the curability and storage stability of composition (X) can be further improved. The upper limit of the difference in exothermic peak top is not particularly limited, but is, for example, 100°C or less.

The difference in onset temperature between the two or more latent curing agents is preferably 10°C or higher, more preferably 13°C or higher, even more preferably 20°C or higher, and 70°C or higher. is particularly preferred. In this case, the curability and storage stability of composition (X) can be further improved.

Among the two or more latent curing agents in (C) the latent curing agent, the one with the lowest exothermic peak top temperature is (CA) the latent curing agent, and the one with the second lowest exothermic peak top temperature is (CB). When used as a latent curing agent, the exothermic peak top temperature of the (CA) latent curing agent is preferably 60° C. or higher and 90° C. or lower, more preferably 65° C. or higher and 80° C. or lower, and 70° C. or higher. It is more preferably 75° C. or lower. (CA) The onset temperature of the latent curing agent is preferably 45° C. or higher and 75° C. or lower, more preferably 50° C. or higher and 65° C. or lower, even more preferably 55° C. or higher and 60° C. or lower. . (CB) The exothermic peak top temperature of the latent curing agent is preferably 75° C. or higher and 200° C. or lower, more preferably 80° C. or higher and 180° C. or lower, and further preferably 85° C. or higher and 175° C. or lower. It is preferably 120° C. or higher and 170° C. or lower, particularly preferably. (CB) The onset temperature of the latent curing agent is preferably 60° C. or higher and 160° C. or lower, more preferably 65° C. or higher and 155° C. or lower, even more preferably 70° C. or higher and 150° C. or lower. , 100° C. or higher and 145° C. or lower.

Examples of the (C) latent curing agent include (C1) a microcapsule-type latent curing agent, (C2) a solid-dispersion-type latent curing agent, (C3) a reactive-group-blocking-type latent curing agent, and (C4) an elution-type curing agent. A latent curing agent, (C5) an ionic latent curing agent, and the like.

(C1) The microcapsule-type latent curing agent usually comprises a shell portion that constitutes the outer shell and a core portion that is wrapped with the shell portion, and the core portion contains a curing agent such as an amine-based curing agent. It is a latent curing agent, and when heated to a predetermined temperature or higher, the shell is destroyed and the curing agent is released, thereby accelerating the curing reaction.

(C1) Examples of commercially available microcapsule-type latent curing agents include Novacure HX-3722, HX-3748, HX-3088, HX-3741, HX-3742, HX-5945HP and HX-9322HP manufactured by Asahi Kasei Corporation. is mentioned.

(C2) The solid-dispersed latent curing agent is usually a solid that is insoluble in epoxy resin at room temperature (25°C), and is cured by being solubilized by melting or the like when heated to a predetermined temperature or higher. It is a latent curing agent that can accelerate the reaction. (C2) Solid dispersion type latent curing agents include, for example, ureas, amine adducts, organic acid hydrazides, imidazole derivatives, dicyandiamide and its derivatives, diaminomaleonitrile and its derivatives, melamine and its derivatives, polyamides, BF _tri -complexes and the like.

(C2) Commercial products of the solid dispersion type latent curing agent include, for example, T&K TOKA Fujicure FXR-1020, FXR-1030, FXR-1032, FXR-1081, FXR-1121, FXR-1131, Ajinomoto Fine Techno Amicure PN-23, PN-H, PN-F, VDH, UDH, AH-123, AH-154 manufactured by San-Apro, U-CAT3512T and U-CAT3513N manufactured by Sun-Apro.

(C3) Reactive group blocking type latent curing agent accelerates the curing reaction by releasing the compound blocking the reactive group at a predetermined temperature or higher by heating to produce a curing agent having a reactive group. It is a latent hardener that causes

(C3) Reactive group blocking type latent curing agents include, for example, a reaction product of an amine compound and an epoxy compound (amine-epoxy adduct system), a reaction product of an amine compound and an isocyanate compound or a urea compound (urea type adduct system) and the like.

(C3) Commercial products of the reactive group blocking type latent curing agent include, for example, Fujicure 7000, 7001 and 7002 manufactured by T&K TOKA.

(C4) The elution-type latent curing agent is a latent curing agent in which a curing agent such as an amine-based curing agent is enclosed in a porous material. , can accelerate the curing reaction.

(C4) Elution-type latent curing agents include, for example, molecular sieve-encapsulated curing agents.

(C5) The ionic latent curing agent contains an ionic compound of an ammonium cation and an organic acid anion, and generates a curing agent such as an amine-based curing agent at a predetermined temperature or higher by heating or the like to initiate a curing reaction. It is an accelerating latent hardener.

(C5) Examples of commercially available ionic latent curing agents include U-CAT SA1 and U-CAT1102 manufactured by San-Apro.

The two or more latent curing agents in (C) the latent curing agent are (C1) a microcapsule-type latent curing agent, (C2) a solid dispersion-type latent curing agent, and (C3) a reactive group-blocking type latent curing agent. It preferably contains two or more latent curing agents selected from the group consisting of agents, and more preferably contains two latent curing agents selected from the group consisting of (C1) to (C3). By using different types of these latent curing agents in combination as a plurality of latent curing agents in (C) the latent curing agent, the composition (X) further improves curability while maintaining storage stability. can be made

(C) When the latent curing agent contains two latent curing agents, the two latent curing agents are a combination of (C1) a microcapsule-type latent curing agent and (C2) a solid dispersion-type latent curing agent. , (C1) a combination of a microcapsule-type latent curing agent and (C3) a reactive group-blocking type latent curing agent, or (C1) a combination of two of the microcapsule-type latent curing agents preferable. By employing a combination of these two latent curing agents in (C) the latent curing agent, the composition (X) can further improve curability while maintaining storage stability.

The ratio of (CA) the latent curing agent is preferably 10 parts by mass or more and 60 parts by mass or less, more preferably 30 parts by mass or more and 50 parts by mass or less, relative to 100 parts by mass of the epoxy resin (A). preferable. The ratio of (CB) the latent curing agent is preferably 5 parts by mass or more and 50 parts by mass or less, more preferably 10 parts by mass or more and 30 parts by mass or less, relative to 100 parts by mass of the epoxy resin (A). preferable.

(CA) The proportion of the latent curing agent is preferably 5% by mass or more and 40% by mass or less, more preferably 10% by mass or more and 30% by mass or less, relative to the entire composition (X). (CB) The proportion of the latent curing agent is preferably 1% by mass or more and 30% by mass or less, more preferably 5% by mass or more and 20% by mass or less, relative to the entire composition (X).

By setting the proportions of (CA) the latent curing agent and (CB) the latent curing agent within the above range, the curability and storage stability of the composition (X) can be further improved.

(C) The ratio of the total amount of the latent curing agent is preferably 50 parts by mass or more and 200 parts by mass or less, and 70 parts by mass or more and 100 parts by mass or less with respect to 100 parts by mass of the epoxy resin (A). is more preferred. (C) The ratio of the total amount of the latent curing agent is preferably 10% by mass or more and 60% by mass or less, more preferably 20% by mass or more and 50% by mass or less, with respect to the entire composition (X). preferable.

[(D) Stabilizer]
(D) Stabilizers are compounds that can react with basic substances such as amines. Even when the composition (X) contains a basic substance such as an amine generated by the decomposition of the latent curing agent (C) before heat curing, the composition (X) can be stored stably by containing the (D) stabilizer. You can keep it in good shape.

(D) Stabilizers include, for example, boric acid esters. Examples of boric acid esters include trimethyl borate, triethyl borate, tributyl borate, tri-n-octyl borate, tri(triethylene glycol methyl ether) boric acid ester, tricyclohexyl borate, trimenthyl borate and other alkyl boric acid esters, trio- Aromatic borate esters such as cresyl borate, tri-m-cresyl borate, tri-p-cresyl borate, triphenyl borate, tri(1,3-butanediol) biborate, tri(2-methyl-2,4- pentanediol) biborate, trioctylene glycol diborate, and the like.

When the composition (X) contains the (D) stabilizer, the ratio of the (D) stabilizer is 0.1 parts by mass or more and 100 parts by mass with respect to 100 parts by mass of the total amount of the (C) latent curing agent. It is preferably not more than 1 part by mass, and more preferably 1 part by mass or more and 10 parts by mass or less. The ratio of (D) the stabilizer is preferably 0.01% by mass or more and 5% by mass or less, and preferably 0.1% by mass or more and 3% by mass or less, relative to the entire composition (X). more preferred.

[(E) other components]
(E) Other components include, for example, inorganic fillers, thixotropic agents, coupling agents, release agents, flame retardants, flame retardant aids, ion trapping agents, pigments such as carbon black, colorants, and stress reduction agents, adhesion imparting agents, silicone flexibilizers, and the like. When the composition (X) contains (E) other components, the ratio of (E) other components is, for example, 0.001% by mass or more and 20% by mass or less with respect to the entire composition (X). .

Since the composition (X) can achieve both high curability and excellent storage stability, for example, in electronic devices, etc., it is suitable for assembly of modules such as camera modules, bonding to housings, and the like. It can be suitably used as an adhesive or the like to be used.

The curing rate of composition (X) by heating at 60° C. for 30 minutes is preferably 90% or more, more preferably 92% or more, still more preferably 95% or more, and 97% or more. It is particularly preferred to have This cure rate may be 100%. This curing rate is a value determined by the measuring method described in the Examples below.

<Cured product>
The cured product according to this embodiment is obtained by curing the composition (X) described above. The cured product of this embodiment is obtained, for example, by heating the composition (X). The heating conditions are appropriately selected depending on the type of the (C) latent curing agent contained in the composition (X). The heating temperature is, for example, 50° C. or higher and 200° C. or lower, preferably 55° C. or higher and 80° C. or lower, and more preferably 60° C. or higher and 65° C. or lower. The heating time is, for example, 10 seconds or more and 5 hours or less, preferably 10 minutes or more and 1 hour or less, and more preferably 20 minutes or more and 40 minutes or less. According to the composition (X), a cured product can be obtained by heating at a relatively low temperature such as 60° C. for 30 minutes.

The cured product of the present embodiment can be suitably used, for example, as a bonding layer for bonding parts by interposing between parts in the manufacture of equipment, and can also be suitably used as a sealing material for sealing electronic parts. can be done.

<Joint body>
A joined body (hereinafter also referred to as a joined body (Y)) according to the present embodiment includes a first member (hereinafter also referred to as a member (1)) and a second member (hereinafter also referred to as a member (2)) and a bonding layer (hereinafter also referred to as bonding layer (h)). The joining layer (h) is interposed between the member (1) and the member (2) to join the member (1) and the member (2). The bonding layer (h) contains a cured product of the composition (X).

Since the conjugate (Y) is produced using the composition (X) having both high curability and excellent storage stability, it can be produced easily and reliably, and the yield can be increased. can.

The bonded body (Y) is composed of the member (1), the member (2), and the bonding layer (h) interposed therebetween and produced by curing the composition (X). The number of members to be adhered is not limited to two, and may be three or more. Also, the number of members included in the joined body (Y) is not limited to two, and may be three or more.

Examples of the member (1) and the member (2) include, but are not limited to, substrates in electronic equipment, electronic devices, and the like. The bonded body (Y) is not particularly limited as long as it is produced by adhering a plurality of members with the composition (X). Examples thereof include various electronic devices and electric devices.

The bonded body (Y) described above is produced by, for example, interposing the composition (X) between the member (1) and the member (2) and heating the composition (X) to form the bonding layer (h). It can be manufactured by

In manufacturing the joined body (Y), first, the composition (X) is interposed between the member (1) and the member (2). The method of interposing is not particularly limited, but for example, after the members are brought into close contact with each other, a method of applying the composition (X) to the places where they are brought into close contact, a method of applying the composition (X) to each member, and then applying the composition (X) to the places where it is applied For example, a method of bringing them into close contact with each other.

Next, the composition (X) interposed between the member (1) and the member (2) is heated. Thereby, the composition (X) is thermally cured to produce the bonding layer (h). By producing the bonding layer (h), the member (1) and the member (2) of the bonded body (Y) are more strongly bonded. The heating conditions are appropriately selected depending on the type of the (C) latent curing agent contained in the composition (X). The heating temperature is, for example, 50° C. or higher and 200° C. or lower, preferably 55° C. or higher and 80° C. or lower, and more preferably 60° C. or higher and 65° C. or lower. The heating time is, for example, 10 seconds or more and 5 hours or less, preferably 10 minutes or more and 1 hour or less, and more preferably 20 minutes or more and 40 minutes or less. A joined body (Y) is produced as described above.

EXAMPLES Hereinafter, the present disclosure will be specifically described with reference to examples, but the present disclosure is not limited only to the examples.

<Preparation of thermosetting adhesive composition>
By mixing raw materials shown in Table 2, a thermosetting adhesive composition was prepared. The details of the raw materials shown in Table 2 are as follows.
- (A) Epoxy resin (A1) Liquid bisphenol A type epoxy resin: "YD8125" manufactured by Nippon Steel Chemical & Materials.
- (B) curing agent (B1) secondary thiol: "Karenzu MT PE1" manufactured by Showa Denko KK. Pentaerythritol tetrakis (3-mercaptobutyrate).
- (B2) primary thiol: "PEMP" manufactured by SC Organic Chemical Co., Ltd.; Pentaerythritol tetrakis (3-mercaptopropionate).
- (C) Latent curing agent (C1-1) Microcapsule-type latent curing agent: "Novacure HXA5945HP" manufactured by Asahi Kasei Corporation.
(C1-2) Microcapsule-type latent curing agent: "Novacure HXA9322HP" manufactured by Asahi Kasei Corporation.
(C1-1) and (C1-2) are masterbatches having a mass ratio of core shell/liquid epoxy resin = about 1/2, containing an amine derivative, an imidazole derivative, or a mixture thereof as a core, and a liquid epoxy resin; is a bisphenol A type epoxy resin, a bisphenol F type epoxy resin, or a mixture thereof.
(C2-1) Solid dispersion type latent curing agent: "Fujicure FXR-1081" manufactured by T&K TOKA.
(C3-1) Reactive group blocking type latent curing agent: "Fujicure 7002" manufactured by T&K TOKA.
- (D) stabilizer (D1) tributylborate. Manufactured by Tokyo Chemical Industry Co., Ltd.

[Measurement of exothermic peak temperature of latent curing agent]
DSC measurement samples (S-1) to (S-4) were prepared by mixing the respective components in the types and amounts shown in Table 1 below. In these DSC measurement samples, the types and proportions of the contained epoxy resin and curing agent, and the proportion of the curing agent component contained in the latent curing agent were made the same. In these DSC measurement samples, a liquid bisphenol A type epoxy resin ("YD8125" manufactured by Nippon Steel Chemical & Materials Co., Ltd.) was used as the epoxy resin, and the ratio of the resin to the entire sample was 40% by mass. A secondary thiol (“Karenzu MT PE1” manufactured by Showa Denko KK) was used as a curing agent, and the proportion of the total sample was 42% by mass. The molar ratio of the sulfanyl groups of the curing agent to the epoxy groups of the epoxy resin (the number of moles of sulfanyl groups/the number of moles of epoxy groups) was 1.0. The ratio of the curing agent component contained in the latent curing agent is 6.1 parts by mass with respect to 100 parts by mass of the epoxy resin.

The prepared DSC measurement sample was measured using a differential scanning calorimetry (DSC) device ("Diamond DSC" manufactured by PerkinElmer Japan Co., Ltd.) in a nitrogen atmosphere under the measurement conditions of a temperature increase rate of 10 ° C./min. got a chart. From the obtained DSC chart, the exothermic peak onset temperature (°C) and the exothermic peak top temperature (°C) were obtained. The measured onset temperature and peak top temperature are shown in Table 1 below.

<Evaluation>
[Curing rate]
The thermosetting adhesive composition was cured at 60°C for 30 minutes using a dryer. About 2 mg of each of the composition before curing and the composition after curing was placed in a measuring pan, and the calorific value was measured using a differential scanning calorimeter (DSC) measuring device ("Diamond DSC" manufactured by Perkin Elmer Japan). The hardening rate was calculated by the following formula (1).
Curing rate (%) = (Ho-Ht) x 100/Ho (1)
(Ho in formula (1) is the calorific value of the composition before curing. Ht is the calorific value of the composition after curing.)
If the curing rate is 90% or more, it can be evaluated as "good", and if it is less than 90%, it can be evaluated as "poor".

[Storage stability]
(45°C for 3 hours)
About 1 g of the thermosetting adhesive composition was placed in a sample bottle and left in a water bath at 45° C. for 3 hours. The fluidity of the composition after 3 hours was observed, and the storage stability at 45°C for 3 hours was evaluated according to the following evaluation criteria.
〇: Not solidified ×: Solidified

(72 hours at 25°C)
80 g of the thermosetting adhesive composition was placed in a 100 cc capacity plastic sample bottle and left in a constant temperature bath at 25° C. for 72 hours. The viscosity of the composition after 72 hours was measured with an E-type viscometer, and the value of the viscosity increase due to standing for 72 hours (viscosity value after standing when the viscosity before standing was taken as 100%) was evaluated according to the following evaluation criteria. was evaluated for storage stability at 25°C for 72 hours.
○: viscosity increase was within 120% ×: viscosity increase was more than 120%

[Adhesion strength]
(Adhesion strength to copper)
The composition was applied onto an adherend made of a copper plate (manufactured by Hirai Seimitsu Kogyo Co., Ltd., material: KFC-1/2H, unplated) to form a coating film having a diameter of 5 mm and a thickness of 0.5 mm. This coating film was thermally cured by heating at 60° C. for 30 minutes to form a cured product. The shear bond strength of the cured product to the adherend was measured using a shear tester. The adhesion strength to copper can be evaluated as "good" when it is 8.5 MPa or more, and as "bad" when it is less than 8.5 MPa.

(Adhesive strength to LCP)
A coating film having a diameter of 5 mm and a thickness of 0.5 mm was prepared by applying the composition onto an adherend made of a liquid crystal polymer (“E463i” manufactured by Polyplastic Co., Ltd.). This coating film was thermally cured by heating at 60° C. for 30 minutes to form a cured product. The shear bond strength of the cured product to the adherend was measured using a shear tester. The adhesive strength to LCP can be evaluated as "good" when it is 9.4 MPa or more, and as "bad" when it is less than 9.4 MPa.

Table 2 below shows the value (%) of the curing rate, the evaluation result of the storage stability (45 ° C. 3 hours), the value (%) of the viscosity increase (25 ° C. 72 hours) and the evaluation result, and the adhesive strength (Cu, LCP) value (MPa) is also shown.

The results in Table 2 show that the thermosetting adhesive compositions of Examples 1 to 6 achieved both high curability and excellent storage stability, and high adhesive strength. On the other hand, some of the thermosetting adhesive compositions of Comparative Examples 1 to 6 had insufficient curability, low adhesive strength, and insufficient storage stability.

Claims (5)

(A) an epoxy resin, (B) a curing agent, and (C) a latent curing agent,
The (B) curing agent contains (B1) a secondary thiol,
The (C) latent curing agent has two or more latent exothermic peak top temperatures different from each other by 10 ° C. or more in the reaction with the epoxy resin and the secondary thiol obtained by differential scanning calorimetry at a temperature increase rate of 10 ° C./min. containing a curing agent,
A thermosetting adhesive composition, wherein the molar ratio of the sulfanyl group of the curing agent (B) to the epoxy group of the epoxy resin (A) is 0.8 or more. The two or more latent curing agents are selected from the group consisting of (C1) a microcapsule type latent curing agent, (C2) a solid dispersion type latent curing agent, and (C3) a reactive group blocking type latent curing agent. 2. The thermosetting adhesive composition of claim 1, comprising two or more latent curing agents. 3. The thermosetting adhesive composition according to claim 1, further comprising (D) a stabilizer. A cured product of the thermosetting adhesive composition according to any one of claims 1 to 3. a first member, a second member, and a joining layer interposed between the first member and the second member to join the first member and the second member; ,
A joined body in which the joining layer comprises a cured product of the thermosetting adhesive composition according to any one of claims 1 to 3.