Adhesive compositions, adhesives for electronic components, and adhesives for portable electronic devices

Abstract

An adhesive composition according to the present invention contains: a moisture-curable resin (A) which has at least one of a polycarbonate skeleton and a polyester skeleton, while having an isocyanate group and a (meth)acryloyl group; and a moisture-curable resin (B) which has isocyanate group, but does not have a (meth)acryloyl group.

Description

[Technical Field]

[0001] The present invention relates to adhesive compositions, adhesives for electronic components, and adhesives for portable electronic devices. [Background technology]

[0002] Conventionally, moisture-curing adhesives containing moisture-curing resins that harden in response to external moisture have been widely used. As an example of a moisture-curing adhesive, Patent Document 1 shows a moisture-curing adhesive mainly composed of an isocyanate-terminated prepolymer obtained by reacting a polyol containing a polycarbonate diol having a specific structure with a polyisocyanate compound such that the isocyanate group / hydroxyl group molar ratio is 1.3 to 3.5. The moisture-curing adhesive described in Patent Document 1 is suitable for clothing applications, exhibits excellent resistance to sweat degradation and hydrolysis, and can be made highly flexible. In particular, it has been shown to have excellent resistance to degradation by higher fatty acids, which are one of the components of sweat.

[0003] In recent years, moisture-curing adhesives have been explored for use in a variety of applications. For example, as disclosed in Patent Document 2, their use in electronic devices such as display devices and semiconductor chips is also being considered. [Prior art documents] [Patent Documents]

[0004] [Patent Document 1] Japanese Patent Publication No. 2003-313531 [Patent Document 2] International Publication No. 2020 / 149377 [Overview of the project] [Problems that the invention aims to solve]

[0005] Incidentally, in recent years, portable electronic devices such as smartphones and tablet personal computers have become widely popular. Wearable devices are also becoming increasingly popular as portable electronic devices. Portable electronic devices such as smartphones and wearable devices are in contact with the skin for extended periods. Therefore, adhesives used in portable electronic devices often come into contact with sebum, sweat, and chemicals contained in skincare products such as cosmetics and sunscreens, and oil resistance is sometimes required. Furthermore, because portable electronic devices are often dropped during use, the adhesives used in these devices are often required to have high impact resistance to prevent components from falling off when dropped.

[0006] For example, as described in Patent Document 1, a certain level of oil resistance can be ensured by using a polyol with a specific structure, such as polycarbonate, in the moisture-curing resin. However, with conventional moisture-curing adhesives, it is difficult to ensure high impact resistance while maintaining oil resistance.

[0007] Therefore, the present invention aims to achieve both high oil resistance and high impact resistance in an adhesive composition having moisture-curing properties. [Means for solving the problem]

[0008] As a result of diligent research, the inventors have found that the above problems can be solved by using at least two moisture-curing resins having the characteristic structures, and have completed the present invention as follows. That is, the present invention provides the following [1] to

[26] . [1] A moisture-curing resin (A) having at least one of a polycarbonate skeleton and a polyester skeleton, and having isocyanate groups and (meth)acryloyl groups, An adhesive composition comprising a moisture-curing resin (B) having isocyanate groups and not having (meth)acryloyl groups. [2] The adhesive composition according to [1] above, wherein the moisture-curing resin (B) has at least one of a polycarbonate skeleton and a polyester skeleton. [3] The adhesive composition according to [1] or [2] above, wherein the moisture-curing resin (B) has a polycarbonate skeleton. [4] The adhesive composition according to any one of the above [1] to [3], wherein the moisture-curing resin (B) has isocyanate groups at both ends. [5] The adhesive composition according to any one of the above [1] to [4], wherein the moisture-curing resin (A) has a polycarbonate skeleton. [6] The adhesive composition according to any one of the above [1] to [5], wherein the moisture-curing resin (A) has an aromatic isocyanate group. [7] The adhesive composition according to any one of the above [1] to [6], further comprising a radical polymerizable compound (C) that does not contain an isocyanate group. [8] The adhesive composition according to [7] above, wherein the radical polymerizable compound (C) contains at least one selected from the group consisting of radical polymerizable compounds having an aromatic ring and radical polymerizable compounds having an imide ring. [9] The adhesive composition according to [7] or [8] above, wherein the radical polymerizable compound (C) contains a compound having a (meth)acryloyl group.

[10] The adhesive composition according to any one of the above [7] to [9], wherein the radical polymerizable compound (C) contains other radical polymerizable compounds other than a radical polymerizable compound having an aromatic ring and a radical polymerizable compound having an imide ring.

[11] The adhesive composition according to

[10] above, comprising at least one of the other radical polymerizable compounds selected from the group consisting of aliphatic urethane (meth)acrylates and (meth)acrylic acid ester compounds.

[12] The adhesive composition according to any one of the above [7] to

[11] , wherein the content of the radical polymerizable compound (C) is 5 parts by mass or more and 50 parts by mass or less based on 100 parts by mass of the total amount of the moisture-curable resin and the radical polymerizable compound.

[13] The adhesive composition according to any one of the above [7] to

[12] , further comprising a photopolymerization initiator.

[14] The adhesive composition according to any one of the above [1] to

[13] , wherein the moisture-curing resin (A) has an isocyanate group at one end and a (meth)acryloyl group at the other end.

[15] The adhesive composition according to any one of the above [1] to

[14] , wherein the moisture-curing resin (A) is a moisture-curing urethane resin (A1).

[16] The adhesive composition according to

[15] above, wherein the moisture-curable urethane resin (A1) is obtained by reacting a polyol compound, a polyisocyanate compound, and a compound having a (meth)acryloyl group.

[17] The adhesive composition according to any one of the above [1] to

[16] , wherein the content of the moisture-curing resin (A) is 0.1 parts by mass or more and 30 parts by mass or less with respect to 100 parts by mass of the total amount of the moisture-curing resin and the radical polymerizable compound.

[18] The adhesive composition according to any one of the above [1] to

[17] , wherein the moisture-curing resin (B) is a moisture-curing urethane resin (B1).

[19] The adhesive composition according to

[18] above, wherein the moisture-curable urethane resin (B1) is obtained by reacting a polyol compound with a polyisocyanate compound.

[20] The adhesive composition according to any one of the above [1] to

[19] , wherein the content of the moisture-curing resin (B) is 30 parts by mass or more and 99.9 parts by mass or less, based on 100 parts by mass of the total amount of the moisture-curing resin and the radical polymerizable compound.

[21] Adhesive composition according to any one of the above [1] to

[20] , further containing a filler

[22] An adhesive for electronic components comprising the adhesive composition described in any one of the above items [1] to

[21] .

[23] An adhesive for portable electronic devices comprising the adhesive composition described in any one of the above items [1] to

[21] .

[24] A cured body of the adhesive composition described in any one of the above items [1] to

[21] .

[25] Use of the adhesive composition described in any one of the above items [1] to

[21] on electronic components.

[26] Use of the adhesive composition described in any one of the above items [1] to

[21] in portable electronic devices. [Advantages of the Invention]

[0009] According to the present invention, in an adhesive composition having moisture curability, it is possible to achieve both high oil resistance and high impact resistance. [Brief Description of the Drawings]

[0010] [Figure 1] It is a schematic diagram showing a method for evaluating adhesive strength, where Fig. 1(a) is a plan view and Fig. 1(b) is a side view. [Figure 2] It is a schematic side view showing a method for evaluating impact resistance. [Modes for Carrying Out the Invention]

[0011] [Adhesive Composition] The adhesive composition of the present invention contains a moisture curable resin (A) and a moisture curable resin (B). Hereinafter, each moisture curable resin will be described in detail.

[0012] [Moisture Curable Resin (A)] The moisture curable resin (A) has at least one of a polycarbonate skeleton and a polyester skeleton, and has an isocyanate group and a (meth)acryloyl group. The adhesive composition of the present invention uses the moisture curable resin (A) having the above structure in combination with the moisture curable resin (B) having the structure described later, so that while ensuring a certain adhesiveness, it is possible to achieve both high oil resistance and high impact resistance. Further, the adhesive composition has moisture curability by having the moisture curable resin (A) and the moisture curable resin (B), and can be used as a moisture curable adhesive. In this specification, the "(meth)acryloyl group" means an acryloyl group or a methacryloyl group, and the same applies to other similar terms.

[0013] The moisture-curing resin (A) may contain either a polycarbonate skeleton or a polyester skeleton in one molecule, or it may contain both a polycarbonate skeleton and a polyester skeleton in one molecule. Furthermore, the moisture-curing resin (A) may be a combination of a moisture-curing resin having a polycarbonate skeleton and a moisture-curing resin having a polyester skeleton. As the moisture-curing resin (A), a moisture-curing resin having a polyester backbone may be used from the viewpoint of flexibility, but it is preferable to use a moisture-curing resin having a polycarbonate backbone. By using a moisture-curing resin having a polycarbonate backbone, oil resistance is improved, and it becomes easier to maintain good adhesive strength even after contact with oil. As the moisture-curing resin (A), it is preferable to use a moisture-curing resin (A) having a polycarbonate skeleton alone, but as described above, it may also be used in combination with a moisture-curing resin (A) having a polyester skeleton. When the moisture-curing resin (A) contains a moisture-curing resin (A) having a polycarbonate skeleton, it is preferable that the moisture-curing resin (A) having a polycarbonate skeleton contains 50% by mass or more, more preferably 75% by mass or more and 100% by mass or less. In moisture-curing resin (A), the polycarbonate skeleton and polyester skeleton are preferably derived from polyol compounds, as described later. Therefore, the polycarbonate skeleton is preferably derived from polycarbonate polyol, and the polyester skeleton is preferably derived from polyester polyol.

[0014] Furthermore, the moisture-curable resin (A) may have one or more isocyanate groups per molecule, but it is preferable that it has one isocyanate group per molecule. Also, the moisture-curable resin (A) may have either an aliphatic isocyanate group or an aromatic isocyanate group or both, but it is preferable that it has an aromatic isocyanate group. Having an aromatic isocyanate group improves the oil resistance of the moisture-curable resin (A), making it easier to maintain good adhesive strength even after contact with oil. It is preferable that the moisture-curable resin (A) has an isocyanate group at its end. Furthermore, an aromatic isocyanate group is an isocyanate group directly bonded to an aromatic ring, while an aliphatic isocyanate group is an isocyanate group directly bonded to an aliphatic carbon atom.

[0015] Aromatic isocyanate groups are isocyanate groups derived from aromatic isocyanate compounds, and details of aromatic isocyanate compounds will be described later. Aliphatic isocyanate groups are isocyanate groups derived from aliphatic isocyanate compounds, and details of aliphatic isocyanate compounds will be described later. The (meth)acryloyl group of the moisture-curable resin (A) may be derived from a compound having a (meth)acryloyl group, as described later. It is preferable that the moisture-curable resin (A) has a (meth)acryloyl group at its terminus. The (meth)acryloyl group of the moisture-curable resin (A) may be reacted by photocuring, as described later, but it is not necessarily required to react by photocuring. That is, the moisture-curable resin (A) may react with other moisture-curable resins (A) by photocuring, or it may react with the radical polymerizable compound (C), as described later, but it is not necessary for them to react. The moisture-curing resin (A) preferably has an isocyanate group at one end and a (meth)acryloyl group at the other end, from the viewpoint of impact resistance. In this specification, "end" means the end of the main chain.

[0016] (Moisture-curing urethane resin (A1)) The moisture-curing resin (A) is preferably a moisture-curing urethane resin (A1). Therefore, it is preferable that the moisture-curing resin (A) has urethane bonds in addition to isocyanate groups and (meth)acryloyl groups. Using a moisture-curing urethane resin (A1) as the moisture-curing resin (A) tends to improve oil resistance and other properties. The case where the moisture-curing resin (A) is a moisture-curing urethane resin (A1) will be explained in more detail below.

[0017] The moisture-curing urethane resin (A1) is preferably obtained by reacting a polyol compound, a polyisocyanate compound, and a compound having a (meth)acryloyl group. The compound having a (meth)acryloyl group may have either a hydroxyl group or an isocyanate group, but it is preferable to have an isocyanate group from the viewpoint of easily introducing the (meth)acryloyl group into the resin (A1). The reactions of the polyol compounds, polyisocyanate compounds, and compounds containing (meth)acryloyl groups described above are typically carried out in a range where the molar ratio of hydroxyl groups (OH) to isocyanate groups (NCO) in these compounds is [NCO] / [OH] = 2.0 to 2.5.

[0018] Moisture-curing urethane resin (A1) may be obtained by reacting a reaction product obtained by reacting a polyol compound with a polyisocyanate compound, and further reacting the product with a compound having an isocyanate group or a hydroxyl group and a (meth)acryloyl group. Alternatively, a reaction product obtained by reacting a polyol compound with a compound having an isocyanate group and a (meth)acryloyl group may be reacted with a polyisocyanate compound. Alternatively, a reaction product obtained by reacting a polyisocyanate compound with a compound having a hydroxyl group and a (meth)acryloyl group may be reacted with a polyol compound. Furthermore, moisture-curing urethane resin (A1) may be obtained by simultaneously reacting a polyol compound, a polyisocyanate compound, and a compound having an isocyanate group or a hydroxyl group and a (meth)acryloyl group. Furthermore, in the synthesis of moisture-curing urethane resin (A1), at least a portion of the moisture-curing urethane resin (B1), described later, may also be synthesized. Examples of such moisture-curing urethane resin (B1) include urethane resins having isocyanate groups at both ends. Moreover, in the synthesis of moisture-curing urethane resin (A1), a urethane (meth)acrylate having (meth)acryloyl groups without isocyanate groups may also be synthesized.

[0019] The polyol compound used as a raw material for moisture-curing urethane resin (A1) has two or more hydroxyl groups in one molecule. Either polycarbonate polyol or polyester polyol can be used as the polyol compound.

[0020] Polycarbonate diols are preferred as polycarbonate polyols. Specific examples of polycarbonate diols include compounds represented by the following formula (1).

[0021] [ka] In equation (1), R is a divalent hydrocarbon group having 4 to 16 carbon atoms, and n is an integer from 2 to 500.

[0022] In formula (1), R is preferably an aliphatic saturated hydrocarbon group. Having an aliphatic saturated hydrocarbon group as R tends to improve heat resistance and flexibility. Furthermore, it reduces the likelihood of yellowing due to thermal degradation, resulting in good weather resistance. R, consisting of an aliphatic saturated hydrocarbon group, may have a chain-like or cyclic structure, but a chain-like structure is preferred. The chain-like structure of R may be linear or branched. n is preferably 5 to 200, more preferably 10 to 150, and even more preferably 20 to 50. Furthermore, the R contained in the polycarbonate polyol constituting the moisture-curing urethane resin (A1) may be used alone or in combination of two or more types. When two or more types are used in combination, it is preferable that at least a portion of them be a chain-like aliphatic saturated hydrocarbon group having 6 or more carbon atoms. Preferably, one molecule contains two or more types of R, and more preferably, one molecule contains two or three types of R. The chain-like aliphatic saturated hydrocarbon group having 6 or more carbon atoms is preferably 6 to 12 carbon atoms, more preferably 6 to 10 carbon atoms, and even more preferably 6 to 8 carbon atoms. Specific examples of R include linear groups such as tetramethylene, pentylene, hexamethylene, heptamethylene, octamethylene, nonamethylene, and decamethylene groups, or branched groups such as methylpentylene groups (e.g., 3-methylpentylene) and methyloctamethylene groups. Multiple R groups in a single molecule may be identical or different. Furthermore, from the viewpoint of achieving an elastic modulus above a certain value, R preferably contains branched aliphatic saturated hydrocarbon groups, and from the viewpoint of weather resistance, R preferably contains linear aliphatic saturated hydrocarbon groups. In polycarbonate polyols, branched and linear R groups may be used in combination. Furthermore, polycarbonate polyols may be used individually or in combination of two or more types.

[0023] Examples of the above-mentioned polyester polyols include polyester polyols obtained by the reaction of a polycarboxylic acid with a polyol, and poly-ε-caprolactone polyols obtained by ring-opening polymerization of ε-caprolactone. Polyester diols are preferred as the polyester polyol.

[0024] Examples of polycarboxylic acids used as raw materials for polyester polyols include divalent aromatic carboxylic acids such as terephthalic acid, isophthalic acid, 1,5-naphthalic acid, and 2,6-naphthalic acid; divalent aliphatic carboxylic acids such as succinic acid, glutaric acid, adipic acid, pimelic acid, suberic acid, azelaic acid, sebacic acid, decamethylenedicarboxylic acid, and dodecamethylenedicarboxylic acid; trivalent or higher aromatic carboxylic acids such as trimellitic acid, trimesic acid, pyromellitic acid, and naphthalentricarboxylic acid; and trivalent or higher aliphatic carboxylic acids such as cyclohexanetricarboxylic acid and hexanetricarboxylic acid. These polycarboxylic acids may be used individually or in combination of two or more. Examples of polyols used as raw materials for polyester polyols include ethylene glycol, propylene glycol, 1,3-propanediol, 1,4-butanediol, neopentyl glycol, 1,5-pentanediol, 1,6-hexanediol, diethylene glycol, and cyclohexanediol.

[0025] In moisture-curing urethane resin (A1), one polyol compound may be used alone, or two or more may be used in combination. In this invention, by using a polycarbonate polyol as the polyol compound that serves as the raw material for the moisture-curing urethane resin (A1), a polycarbonate skeleton can be introduced into the moisture-curing urethane resin (A1), thereby obtaining a moisture-curing urethane resin (A1) having a polycarbonate skeleton. Similarly, by using a polyester polyol as the polyol compound that serves as the raw material for the moisture-curing urethane resin (A1), a polyester skeleton can be introduced into the moisture-curing urethane resin (A1), thereby obtaining a moisture-curing urethane resin (A1) having a polyester skeleton.

[0026] Furthermore, the moisture-curing urethane resin (A1) may also incorporate both a polycarbonate backbone and a polyester backbone by using both a polycarbonate polyol and a polyester polyol as the polyol compound used as a raw material for the moisture-curing urethane resin (A1). In other words, the moisture-curing urethane resin (A1) may be a moisture-curing urethane resin (A1) having both a polycarbonate backbone and a polyester backbone in a single molecule. In this specification, the moisture-curing urethane resin (A1) having a polycarbonate backbone also includes the moisture-curing urethane resin (A1) containing both a polycarbonate backbone and a polyester backbone. The same applies to other similar terms.

[0027] The polyisocyanate compound used as a raw material for moisture-curing urethane resin (A1) has two or more isocyanate groups in one molecule, but it is preferable that it has two isocyanate groups. Examples of polyisocyanate compounds include aromatic polyisocyanate compounds and aliphatic polyisocyanate compounds. Examples of aromatic polyisocyanate compounds include diphenylmethane diisocyanate, a liquid modified product of diphenylmethane diisocyanate, tolylene diisocyanate, and naphthalene-1,5-diisocyanate. Aromatic polyisocyanate compounds may also be large quantities of these compounds, or polymeric MDIs may be used. Diphenylmethane diisocyanate is preferred as the aromatic polyisocyanate compound. Examples of aliphatic polyisocyanate compounds include hexamethylene diisocyanate, trimethylhexamethylene diisocyanate, lysine diisocyanate, norbornane diisocyanate, transcyclohexane-1,4-diisocyanate, isophorone diisocyanate, hydrogenated xylylene diisocyanate, hydrogenated diphenylmethane diisocyanate, cyclohexane diisocyanate, bis(isocyanate-methyl)cyclohexane, and dicyclohexylmethane diisocyanate. Aliphatic polyisocyanate compounds may also be obtained by increasing the amount of these compounds. Polyisocyanate compounds may be used individually or in combination of two or more.

[0028] In the present invention, when an aromatic polyisocyanate compound is used in the synthesis of moisture-curable urethane resin (A1), the moisture-curable resin (A) contains aromatic isocyanate groups, and when an aliphatic polyisocyanate compound is used, the moisture-curable resin (A) contains aliphatic isocyanate groups. Therefore, it is preferable to use an aromatic polyisocyanate compound as the polyisocyanate compound.

[0029] The compound having a (meth)acryloyl group that serves as a raw material for moisture-curing urethane resin (A1) may contain either an isocyanate group or a hydroxyl group, as described above, but it is preferable that the compound has both an isocyanate group and a (meth)acryloyl group. Examples of compounds having both an isocyanate group and a (meth)acryloyl group include the compound represented by the following formula (2).

[0030] [ka] In formula (2), R 1 R represents a hydrogen or methyl group. 2 This represents a divalent saturated hydrocarbon group having 1 to 10 carbon atoms, which may have an ether bond.

[0031] Preferred compounds having an isocyanate group and a (meth)acryloyl group include 2-(meth)acryloyloxyethyl isocyanate and 2-(meth)acryloyloxyethoxyethyl isocyanate.

[0032] Examples of compounds having hydroxyl groups and (meth)acroyl groups that can be used as raw materials for moisture-curing urethane resin (A1) include hydroxyalkyl (meth)acrylates such as 2-hydroxyethyl (meth)acrylate, 2-hydroxypropyl (meth)acrylate, 2-hydroxybutyl (meth)acrylate, and 4-hydroxybutyl (meth)acrylate. Furthermore, compounds having hydroxyl groups and (meth)acryloyl groups may be used as raw materials for moisture-curing urethane resin (A1) by reacting them with various diisocyanate compounds in a ratio such that the isocyanate group / hydroxyl group (molar ratio) is 2.

[0033] The weight-average molecular weight of the moisture-curable resin (A) is not particularly limited, but is preferably 1,000 to 50,000, more preferably 2,000 to 30,000, and even more preferably 3,000 to 20,000. When the weight-average molecular weight is above the lower limit, the crosslinking density does not become too high during curing, and flexibility after curing tends to be high. Furthermore, for example, in the semi-cured state after photocuring and before moisture curing, it is easier to ensure a certain level of hardness and excellent shape retention. Moreover, when the weight-average molecular weight is below the upper limit, the adhesive composition tends to have appropriate fluidity even at room temperature (for example, 25°C) before curing, resulting in good applicability. In this specification, the weight-average molecular weight is determined by measuring it using gel permeation chromatography (GPC) and converting it to polystyrene equivalent. A suitable column for measuring the weight-average molecular weight in polystyrene equivalent using GPC is the Shodex LF-804 (manufactured by Showa Denko Corporation). A suitable solvent for GPC is tetrahydrofuran.

[0034] The content of the moisture-curable resin (A) in the adhesive composition is, for example, 0.1 parts by mass or more and 30 parts by mass or less, based on 100 parts by mass of the total amount of the moisture-curable resin and the radical polymerizable compound. By having the content of component (A) within the above range, the adhesive composition can easily improve impact resistance while maintaining good oil resistance and adhesion. From these viewpoints, the above content of the moisture-curable resin (A) is preferably 0.5 parts by mass or more and 25 parts by mass or less, more preferably 0.7 parts by mass or more and 15 parts by mass or less, and even more preferably 1 part by mass or more and 10 parts by mass or less. In this specification, the total amount of moisture-curable resin and radical polymerizable compound refers to the total amount of moisture-curable resin when radical polymerizable compound (C) component is not included.

[0035] [Moisture-curing resin (B)] The moisture-curable resin (B) in this invention is a resin having isocyanate groups but not (meth)acryloyl groups. By having the moisture-curable resin (B), the adhesive composition can be given appropriate adhesive performance.

[0036] The moisture-curing resin (B) preferably has at least one of a polycarbonate skeleton and a polyester skeleton. Having either of these makes it easier to achieve both oil resistance and impact resistance in the moisture-curing resin (B). The moisture-curing resin (B), having at least one of a polycarbonate skeleton and a polyester skeleton, may contain either a polycarbonate skeleton or a polyester skeleton in a single molecule, or it may contain both a polycarbonate skeleton and a polyester skeleton in a single molecule. Furthermore, the moisture-curing resin (B) may be a combination of a moisture-curing resin having a polycarbonate skeleton and a moisture-curing resin having a polyester skeleton.

[0037] Furthermore, it is more preferable that the moisture-curing resin (B) has a polycarbonate skeleton. By using a moisture-curing resin (B) having a polycarbonate skeleton in the adhesive composition, it becomes easier to achieve both high oil resistance and high impact resistance. In particular, oil resistance is improved, making it easier to ensure high adhesive strength even after contact with oil. As the moisture-curing resin (B), it is preferable to use a moisture-curing resin (B) having a polycarbonate skeleton alone, but as described above, it may also be used in combination with a moisture-curing resin (B) having a polyester skeleton. When the moisture-curing resin (B) contains a moisture-curing resin (B) having a polycarbonate skeleton, it is preferable that the moisture-curing resin (B) having a polycarbonate skeleton be contained in an amount of 50% by mass or more, more preferably 75% by mass or more and 100% by mass or less.

[0038] As described later, the polycarbonate and polyester skeletons in the moisture-curing resin (B) are preferably derived from polyol compounds. Therefore, the polycarbonate skeleton is preferably derived from polycarbonate polyol, and the polyester skeleton is preferably derived from polyester polyol.

[0039] Furthermore, moisture-curable resin (B) may have one or more isocyanate groups per molecule, but it is preferable to have two or more isocyanate groups per molecule, and more preferably two. Also, moisture-curable resin (B) may have either aliphatic isocyanate groups or aromatic isocyanate groups, or both, but it is preferable to have aromatic isocyanate groups. By having aromatic isocyanate groups, moisture-curable resin (B) has improved oil resistance and is more likely to maintain good adhesive strength even after contact with oil.

[0040] Aromatic isocyanate groups are isocyanate groups derived from aromatic isocyanate compounds, while aliphatic isocyanate groups are isocyanate groups derived from aliphatic isocyanate compounds. The moisture-curable resin (B) preferably has an isocyanate group at its terminus, and more preferably has isocyanate groups at both terminus. Having isocyanate groups at both terminus makes it easier for the moisture-curable resin (B) to increase in molecular weight through moisture curing, thus making it easier to ensure high adhesion. Furthermore, from the viewpoint of oil resistance, it is even more preferable for the moisture-curable resin (B) to have aromatic isocyanate groups at both terminus.

[0041] (Moisture-curing urethane resin (B1)) The moisture-curing resin (B) is preferably a moisture-curing urethane resin (B1). Therefore, it is preferable that the moisture-curing resin (B) has urethane bonds in addition to isocyanate groups. Using a moisture-curing urethane resin (B1) as the moisture-curing resin (B) tends to improve oil resistance and other properties. The case where the moisture-curing resin (B) is a moisture-curing urethane resin (B1) will be explained in more detail below. The moisture-curing urethane resin (B1) may have one isocyanate group or two or more isocyanate groups in one molecule, but it is more preferable to have isocyanate groups at both ends of the main chain as described above.

[0042] Moisture-curing urethane resin (B1) can be obtained by reacting a polyol compound with a polyisocyanate compound. The reaction between the polyol compound and the polyisocyanate compound is usually carried out in the range of [NCO] / [OH] = 2.0 to 2.5, where the molar ratio of hydroxyl groups (OH) in the polyol compound to isocyanate groups (NCO) in the polyisocyanate compound is in the range of [NCO] / [OH].

[0043] As the polyol compound used in the moisture-curing urethane resin (B1), known polyol compounds commonly used in the production of polyurethane can be used. From the viewpoint of achieving both oil resistance and impact resistance, polyester polyols and polycarbonate polyols are preferred, with polycarbonate polyols being particularly preferred. In this invention, a polycarbonate polyol can be used as the polyol compound that serves as the raw material for the moisture-curing urethane resin (B1) to introduce a polycarbonate skeleton into the moisture-curing urethane resin (B1), thereby obtaining a moisture-curing urethane resin (B1) having a polycarbonate skeleton. Alternatively, a polyester polyol can be used as the polyol compound that serves as the raw material for the moisture-curing urethane resin (B1) to introduce a polyester skeleton into the moisture-curing urethane resin (B1), thereby obtaining a moisture-curing urethane resin (B1) having a polyester skeleton. Furthermore, both a polycarbonate skeleton and a polyester skeleton may be introduced into a single molecule.

[0044] The polycarbonate polyols and polyester polyols used as raw materials for moisture-curing urethane resin (B1) are those listed as raw materials for moisture-curing urethane resin (A1), and the explanations for them are the same, so those explanations will be omitted.

[0045] The polyisocyanate compound used as a raw material for the moisture-curing urethane resin (B1) has two or more isocyanate groups in one molecule, preferably two isocyanate groups. Examples of the polyisocyanate compound include aromatic polyisocyanate compounds and aliphatic polyisocyanate compounds. As the aromatic polyisocyanate compound and aliphatic polyisocyanate compound, those listed as raw materials for the moisture-curing urethane resin (A1) can be used, and the description is the same, so the description is omitted. As the polyisocyanate compound, similar to the moisture-curing urethane resin (B1), an aromatic polyisocyanate compound is preferred, and among them, diphenylmethane diisocyanate is preferred.

[0046] The moisture-curing resin (B) may be a resin having an organic silyl group represented by the following formula (3) in addition to the isocyanate group.

[0047]

Chemical formula

[0048] In the above formula (3), when R 3 and R 4 are each an aryl group, examples of the aryl group include a phenyl group, a naphthyl group, a 2-methylphenyl group, etc. In the above formula (3), from the viewpoint of exhibiting better adhesiveness, x is preferably 1 or 2. Note that when x in the above formula (3) is 0, it means that the silicon atom is bonded to three -OR 3 without bonding to the atom or group represented by R 4 In the group represented by formula (3), R 3 and R 4From the viewpoint of improving adhesion, it is preferable that the alkyl group has 1 to 5 carbon atoms, and more preferably that it is either a methyl group or an ethyl group.

[0049] Even when the moisture-curable resin (B) contains the above-mentioned organic silyl group, it is preferable that the moisture-curable resin (B) is a moisture-curable urethane resin (B1), and therefore, in addition to the isocyanate group and the organic silyl group, it is preferable that it has a urethane bond. Furthermore, when the moisture-curable resin (B) contains the above-mentioned organic silyl group, it is preferable that it has both the organic silyl group and the isocyanate group at one end.

[0050] A moisture-curable urethane resin (B1) having an organic silyl group can be obtained by reacting a compound having a urethane bond and an isocyanate group, obtained by reacting a polyol compound with a polyisocyanate compound, with a compound having a reactive functional group and a group represented by formula (3). The above "reactive functional group" refers to a group that can react with the above compound having a urethane bond and an isocyanate group, and a group that can react with an isocyanate group is preferred.

[0051] The polyol compounds and polyisocyanate compounds are as described above. Examples of compounds having the above-mentioned reactive functional group and the group represented by formula (3) include 3-mercaptopropyltrimethoxysilane, 3-mercaptopropyltriethoxysilane, 3-glycidoxypropyltrimethoxysilane, 3-glycidoxypropyltriethoxysilane, 2-(3,4-epoxycyclohexyl)ethyltrimethoxysilane, 3-glycidoxypropylmethyldiethoxysilane, 3-aminopropyltrimethoxysilane, 3-aminopropyltriethoxysilane, 3-(2-aminoethyl)aminopropyltrimethoxysilane, 3-(2-aminoethyl)aminopropyltriethoxysilane, and 3-(2-aminoethyl) Examples include minopropylmethyldimethoxysilane, 3-(meth)acryloyloxypropyltrimethoxysilane, 3-(meth)acryloyloxypropyltriethoxysilane, 3-(meth)acryloyloxypropylmethyldimethoxysilane, 3-(meth)acryloyloxypropylmethyldiethoxysilane, vinyltrimethoxysilane, vinyltriethoxysilane, 3-isocyanatetopropyltrimethoxysilane, 3-mercaptopropylmethyldimethoxysilane, 3-mercaptopropylmethyldiethoxysilane, 3-glycidoxypropylmethyldimethoxysilane, and 3-glycidoxypropylmethyldiethoxysilane. Among these, those having a thiol group as a reactive functional group are preferred from the viewpoint of reactivity.

[0052] The weight-average molecular weight of the moisture-curing resin (B) is not particularly limited, but is preferably between 1,000 and 50,000. When the weight-average molecular weight is above the lower limit, the crosslinking density does not become too high during curing, and flexibility after curing tends to be high. Furthermore, for example, in the semi-cured state after photocuring and before moisture curing, it is easier to ensure a certain level of hardness and excellent shape retention. Moreover, when the weight-average molecular weight is below the upper limit, the adhesive composition has appropriate fluidity even at room temperature (e.g., 25°C) before curing, resulting in good room-temperature application properties. From these perspectives, the weight-average molecular weight of the moisture-curing resin (B) is more preferably 2,000 to 30,000, and even more preferably 3,000 to 20,000.

[0053] The content of moisture-curable resin (B) in the adhesive composition is, for example, 30 parts by mass or more and 99.9 parts by mass or less, based on 100 parts by mass of the total amount of moisture-curable resin and radical polymerizable compound. If the content is above the lower limit, it becomes easier to improve the adhesive strength and impart appropriate moisture-curability. If the content is below the upper limit, it becomes easier to include a certain amount or more of moisture-curable resin (A), making it easier to achieve both oil resistance and impact resistance. From the above viewpoints, and from the viewpoint of containing a certain amount or more of the radical polymerizable compound (C) described later, the above content of the moisture-curable resin (B) is preferably 45 parts by mass or more and 94 parts by mass or less, more preferably 50 parts by mass or more and 88 parts by mass or less, and even more preferably 53 parts by mass or more and 80 parts by mass or less.

[0054] The moisture-curable resin is preferably composed of the above-mentioned moisture-curable resins (A) and (B), but may also contain moisture-curable resins other than moisture-curable resins (A) and (B) as long as the effects of the present invention are not impaired. The moisture-curable resin is a resin that can harden by reacting with water present in the air or on an adherend, and preferably has functional groups such as isocyanate groups and organosilyl groups. The content of moisture-curing resins other than the above-mentioned moisture-curing resins (A) and (B) is not particularly limited, but may be, for example, 30 parts by mass or less, or about 10 parts by mass or less, when the total amount of moisture-curing resins is 100 parts by mass.

[0055] [Radical polymerizable compound (C)] The adhesive composition of the present invention preferably contains a radical polymerizable compound (C) in addition to the moisture-curable resins (A) and (B) described above. The radical polymerizable compound (C) is a compound that does not contain an isocyanate group. In this invention, by including a radical polymerizable compound (C), photocurability can be easily imparted to the adhesive composition, making it a photo-moisture-curable adhesive composition with good photocurability. Therefore, the adhesive composition can be given a certain level of adhesive strength simply by irradiating it with light, and a certain level of adhesive strength can be ensured even in the semi-cured state after photocuring and before moisture curing. Furthermore, in the semi-cured state after photocuring and before moisture curing, it has a certain level of hardness and it is easier to ensure excellent shape retention. With excellent shape retention, for example, an adhesive composition applied by a dispenser can maintain a certain height after photocuring, so that a certain distance can be maintained between adherends by the cured body formed from the adhesive composition. Furthermore, by using a radical polymerizable compound (C) in addition to moisture-curing resins (A) and (B), the viscosity of the adhesive composition tends to decrease. As a result, the adhesive composition can more easily maintain appropriate fluidity at room temperature (e.g., 25°C) before curing, and its applicability can be improved. Furthermore, the radical polymerizable compound (C) is preferably a compound that does not exhibit moisture curing properties, and therefore, it is preferable that it does not contain moisture-curing functional groups such as the organosilyl group mentioned above.

[0056] Radical polymerizable compounds (C) have a radical polymerizable functional group in their molecule. Suitable radical polymerizable functional groups include compounds having an unsaturated double bond, such as (meth)acryloyl groups, vinyl groups, styryl groups, and allyl groups. Among the above, the (meth)acryloyl group is preferred from the viewpoint of adhesion; that is, the radical polymerizable compound (C) preferably contains a compound having a (meth)acryloyl group. The compound having a (meth)acryloyl group will also be referred to as "(meth)acrylic compound" below.

[0057] The radical polymerizable compound (C) preferably contains at least one selected from the group consisting of radical polymerizable compounds having an aromatic ring and radical polymerizable compounds having an imide ring. These compounds are preferably monofunctional, having one radical polymerizable functional group in the molecule, but may also be polyfunctional compounds having two or more radical polymerizable functional groups.

[0058] Examples of radical polymerizable compounds having aromatic rings include monofunctional (meth)acrylic acid ester compounds having aromatic rings. Specifically, these include phenylalkyl (meth)acrylates such as benzyl (meth)acrylate and 2-phenylethyl (meth)acrylate, and phenoxyalkyl (meth)acrylates such as phenoxyethyl (meth)acrylate. Furthermore, (meth)acrylates having multiple benzene rings, such as fluorene skeletons and biphenyl skeletons, may also be used, specifically including fluorene-type (meth)acrylates and ethoxylated o-phenylphenol acrylate. Other examples include phenoxypolyoxyethylene-based (meth)acrylates such as phenoxydiethylene glycol (meth)acrylate, phenoxypolyethylene glycol (meth)acrylate, nonylphenoxydiethylene glycol (meth)acrylate, and nonylphenoxypolyethylene glycol (meth)acrylate. Among these, phenoxyalkyl (meth)acrylate is preferred, and phenoxyethyl (meth)acrylate is more preferred. Furthermore, examples of radical polymerizable compounds having an imide ring include (meth)acrylic acid ester compounds having an imide ring, such as N-(meth)acryloyloxyethylhexahydrophthalimide, and vinyl compounds having an imide ring, such as N-vinylphthalimide, N-allylphthalimide, N-(3-buten-1-in)phthalimide, and N-allyloxyphthalimide.

[0059] The adhesive composition contains at least one radical polymerizable compound having an aromatic ring and a radical polymerizable compound having an imide ring, thereby improving oil resistance and making it easier to maintain better adhesive strength even after contact with oil. The radical polymerizable compound (C) may contain either a radical polymerizable compound having an aromatic ring or a radical polymerizable compound having an imide ring, or it may contain both. Furthermore, it is more preferable that the radical polymerizable compound (C) contains at least a radical polymerizable compound having an imide ring.

[0060] The radical polymerizable compound (C) may consist of at least one selected from radical polymerizable compounds having an aromatic ring and radical polymerizable compounds having an imide ring, but may also contain other radical polymerizable compounds ("other radical polymerizable compounds"). In the adhesive composition, the content of compounds selected from the group consisting of radical polymerizable compounds having an aromatic ring and radical polymerizable compounds having an imide ring is preferably 20% by mass or more, more preferably 25% by mass or more, even more preferably 50% by mass or more, and even more preferably 80% by mass or more, relative to the total amount of radical polymerizable compound (C). Furthermore, the above content of these compounds may be 100% by mass or less. Increasing the content of these compounds improves the oil resistance of the adhesive composition, allowing it to maintain high adhesive strength even after contact with oil.

[0061] Other radical polymerizable compounds include various aliphatic (meth)acrylic compounds. Specifically, other radical polymerizable compounds may include aliphatic urethane (meth)acrylates, or (meth)acrylic acid ester compounds other than aliphatic urethane (meth)acrylates. Furthermore, as mentioned above, the aliphatic urethane (meth)acrylate does not have residual isocyanate groups. Other radical polymerizable compounds may be monofunctional or polyfunctional, such as difunctional compounds, but monofunctional compounds are preferred. In addition, when using a monofunctional aliphatic urethane (meth)acrylate, it may be used in combination with polyfunctional compounds such as difunctional compounds.

[0062] As described above, the aliphatic urethane (meth)acrylate is preferably monofunctional. For example, a compound obtained by reacting an isocyanate compound with a (meth)acrylic acid derivative having a hydroxyl group can be used. Examples of (meth)acrylic acid derivatives having the above-mentioned hydroxyl group include mono(meth)acrylates of dihydric alcohols such as ethylene glycol, propylene glycol, 1,3-propanediol, 1,3-butanediol, 1,4-butanediol, and polyethylene glycol, as well as mono(meth)acrylates of trihydric alcohols such as trimethylolethane, trimethylolpropane, and glycerin.

[0063] Examples of isocyanate compounds used to obtain aliphatic urethane (meth)acrylates include aliphatic monoisocyanates such as alkane monoisocyanates (preferably with 3 to 12 carbon atoms in the alkane) such as butane isocyanate, hexane isocyanate, octane isocyanate, and decane isocyanate, and cyclic aliphatic monoisocyanates such as cyclopentane isocyanate, cyclohexane isocyanate, and isophorone monoisocyanate. More specifically, monofunctional aliphatic urethane (meth)acrylates are preferably urethane (meth)acrylates obtained by reacting the above-mentioned monoisocyanate compound with a dihydric alcohol mono(meth)acrylate. Preferred specific examples include 1,2-ethanediol 1-acrylate 2-(N-alkylcarbamate), such as 1,2-ethanediol 1-acrylate 2-(N-butylcarbamate). Furthermore, examples of polyfunctional aliphatic urethane (meth)acrylates include reaction products obtained by reacting a polyol compound with a compound having an isocyanate group and a (meth)acryloyl group. Specifically, examples include urethane (meth)acrylates having (meth)acryloyl groups at both ends. Details of the polyol compound and the compound having an isocyanate group and a (meth)acryloyl group are as described in the raw materials for moisture-curable urethane resin (A1).

[0064] (Meth)acrylic acid ester compounds other than aliphatic urethane (meth)acrylate may be monofunctional or polyfunctional, but monofunctional is preferred. Specifically, monofunctional (meth)acrylic acid ester compounds include, for example, methyl (meth)acrylate, ethyl (meth)acrylate, propyl (meth)acrylate, n-butyl (meth)acrylate, isobutyl (meth)acrylate, t-butyl (meth)acrylate, n-octyl (meth)acrylate, isooctyl (meth)acrylate, 2-ethylhexyl (meth)acrylate, isononyl (meth)acrylate, and isodecyl (meth)acrylate. Alkyl (meth)acrylates such as lauryl (meth)acrylate, isomiristyl (meth)acrylate, and stearyl (meth)acrylate; cyclohexyl (meth)acrylate, 4-tert-butylcyclohexyl (meth)acrylate, 3,3,5-trimethylcyclohexyl (meth)acrylate, isobornyl (meth)acrylate, dicyclopentenyl (meth)acrylate, and other alicyclic (meth)acrylates; 2-hydroxyethyl (meth)acrylate Examples include hydroxyalkyl (meth)acrylates such as rilate, 2-hydroxypropyl (meth)acrylate, 2-hydroxybutyl (meth)acrylate, and 4-hydroxybutyl (meth)acrylate; alkoxyalkyl (meth)acrylates such as 2-methoxyethyl (meth)acrylate, 2-ethoxyethyl (meth)acrylate, and 2-butoxyethyl (meth)acrylate; alkoxyethylene glycol (meth)acrylates such as methoxyethylene glycol (meth)acrylate and ethoxyethylene glycol (meth)acrylate; polyoxyethylene-based (meth)acrylates such as methoxydiethylene glycol (meth)acrylate, methoxytriethylene glycol (meth)acrylate, methoxypolyethylene glycol (meth)acrylate, ethoxydiethylene glycol (meth)acrylate, ethoxytriethylene glycol (meth)acrylate, and ethoxypolyethylene glycol (meth)acrylate.

[0065] Furthermore, examples of monofunctional (meth)acrylic acid ester compounds include heterocyclic (meth)acrylates such as tetrahydrofurfuryl (meth)acrylate, alkoxylated tetrahydrofurfuryl (meth)acrylate, cyclic trimethylolpropaneformal (meth)acrylate, and 3-ethyl-3-oxetanylmethyl (meth)acrylate, as well as 2,2,2-trifluoroethyl (meth)acrylate, 2,2,3,3-tetrafluoropropyl (meth)acrylate, 1H,1H,5H-octafluoropentyl (meth)acrylate, dimethylaminoethyl (meth)acrylate, diethylaminoethyl (meth)acrylate, 2-(meth)acryloyloxyethyl succinic acid, 2-(meth)acryloyloxyethyl-2-hydroxypropyl phthalate, glycidyl (meth)acrylate, and 2-(meth)acryloyloxyethyl phosphate.

[0066] Examples of bifunctional (meth)acrylic acid ester compounds include 1,3-butanediol di(meth)acrylate, 1,4-butanediol di(meth)acrylate, 1,6-hexanediol di(meth)acrylate, 1,9-nonanediol di(meth)acrylate, 1,10-decanediol di(meth)acrylate, 2-n-butyl-2-ethyl-1,3-propanediol di(meth)acrylate, ethylene glycol di(meth)acrylate, diethylene glycol di(meth)acrylate, tetraethylene glycol di(meth)acrylate, polyethylene glycol di(meth)acrylate, and dipropylene glycol di(meth)acrylate. Examples include acrylates, tripropylene glycol di(meth)acrylate, polypropylene glycol di(meth)acrylate, dimethylol dicyclopentadienyl di(meth)acrylate, neopentyl glycol di(meth)acrylate, ethylene oxide-modified isocyanurate di(meth)acrylate, 2-hydroxy-3-(meth)acryloyloxypropyl(meth)acrylate, carbonate diol di(meth)acrylate, polyether diol di(meth)acrylate, polyester diol di(meth)acrylate, polycaprolactone diol di(meth)acrylate, polybutadiene diol di(meth)acrylate, etc.

[0067] Furthermore, examples of (meth)acrylic acid ester compounds with three or more functionalities include trimethylolpropane tri(meth)acrylate, ethylene oxide-added trimethylolpropane tri(meth)acrylate, propylene oxide-added trimethylolpropane tri(meth)acrylate, caprolactone-modified trimethylolpropane tri(meth)acrylate, pentaerythritol tri(meth)acrylate, ethylene oxide-added isocyanuric acid tri(meth)acrylate, glycerin tri(meth)acrylate, propylene oxide-added glycerin tri(meth)acrylate, tris(meth)acryloyloxyethyl phosphate, ditrimethylolpropane tetra(meth)acrylate, pentaerythritol tetra(meth)acrylate, dipentaerythritol penta(meth)acrylate, and dipentaerythritol hexa(meth)acrylate.

[0068] Other radical polymerizable compounds besides those mentioned above can also be used as appropriate. Examples of other radical polymerizable compounds include (meth)acrylamide compounds such as N,N-dimethyl(meth)acrylamide, N-(meth)acryloylmorpholine, N-hydroxyethyl(meth)acrylamide, N,N-diethyl(meth)acrylamide, N-isopropyl(meth)acrylamide, and N,N-dimethylaminopropyl(meth)acrylamide, as well as vinyl compounds such as N-vinyl-2-pyrrolidone and N-vinyl-ε-caprolactam. Epoxy(meth)acrylates can also be used as (meth)acrylic acid ester compounds.

[0069] As radical polymerizable compounds other than those having an aromatic ring and radical polymerizable compounds having an imide ring, at least one selected from the group consisting of aliphatic urethane (meth)acrylate and (meth)acrylic acid ester compounds is preferred. Among these, at least one selected from the group consisting of aliphatic urethane (meth)acrylate and (meth)acrylate having an alicyclic structure is more preferred. Other radical polymerizable compounds may be used individually or in combination of two or more.

[0070] The content of the radical polymerizable compound (C) is preferably 5 parts by mass or more and 50 parts by mass or less, based on 100 parts by mass of the total amount of the moisture-curable resin and the radical polymerizable compound. When the content of the radical polymerizable compound (C) is above the lower limit, it becomes easier to appropriately impart photocurability to the adhesive composition, and it also becomes easier to ensure shape retention after photocuring and before moisture curing. Furthermore, it becomes easier to improve the applicability of the adhesive composition. On the other hand, by keeping it below the upper limit, the amount of moisture-curable resins (A) and (B) can be kept above a certain amount, allowing appropriate moisture curability to be imparted to the adhesive composition. From these viewpoints, the content of the radical polymerizable compound (C) is more preferably 10 parts by mass or more and 45 parts by mass or less, and even more preferably 15 parts by mass or more and 40 parts by mass or less.

[0071] (Photopolymerization initiator) The adhesive composition of the present invention may further contain a photopolymerization initiator. By containing a photopolymerization initiator, the adhesive composition can be appropriately imparted with photocurability. It is preferable to use a photopolymerization initiator when the adhesive composition contains a radical polymerizable compound (C). Examples of photopolymerization initiators include benzophenone compounds, acetophenone compounds, acylphosphine oxide compounds, titanocene compounds, oxime ester compounds, benzoin ether compounds, and thioxanthones. Examples of commercially available photopolymerization initiators include IRGACURE184, IRGACURE369, IRGACURE379, IRGACURE651, IRGACURE784, IRGACURE819, IRGACURE907, IRGACURE2959, IRGACURE OXE01, and Lucilin TPO (all manufactured by BASF), as well as benzoin methyl ether, benzoin ethyl ether, and benzoin isopropyl ether (all manufactured by Tokyo Chemical Industry Co., Ltd.).

[0072] The content of the photopolymerization initiator in the adhesive composition is preferably 0.01 parts by mass to 8 parts by mass, more preferably 0.1 parts by mass to 6 parts by mass, and even more preferably 0.4 parts by mass to 4 parts by mass, per 100 parts by mass of the adhesive composition. By having the photopolymerization initiator content within this range, the resulting adhesive composition exhibits excellent photocurability and storage stability. Furthermore, within this range, the photoradical polymerization compound (C) is properly cured, making it easier to achieve good adhesive strength.

[0073] (Moisture curing accelerating catalyst) The adhesive composition of the present invention may contain a moisture curing accelerating catalyst that promotes the moisture curing reaction of a moisture-curing resin. By using a moisture curing accelerating catalyst, the adhesive composition becomes more moisture-curable and easier to enhance in terms of adhesive strength. Examples of moisture-curing accelerating catalysts include amine compounds and metal catalysts. Examples of amine compounds include compounds having a morpholine skeleton such as di(methylmorpholino)diethyl ether, 4-morpholinopropylmorpholine, and 2,2'-dimorpholinodiethyl ether; dimethylamino group-containing amine compounds having two dimethylamino groups such as bis(2-dimethylaminoethyl) ether and 1,2-bis(dimethylamino)ethane; triethylamine, 1,4-diazabicyclo[2.2.2]octane, and 2,6,7-trimethyl-1,4-diazabicyclo[2.2.2]octane. Examples of metal catalysts include tin compounds such as di-n-butyltin dilaurate, di-n-butyltin diacetate, and tin octoate; zinc compounds such as zinc octoate and zinc naphthenate; and other metal compounds such as zirconium tetraacetylacetonate, copper naphthenate, and cobalt naphthenate. The content of the moisture curing accelerator in the adhesive composition is preferably 0.1 parts by mass or more and 10 parts by mass or less, more preferably 0.2 parts by mass or more and 8 parts by mass or less, and even more preferably 0.3 parts by mass or more and 5 parts by mass or less, per 100 parts by mass of the adhesive composition.

[0074] (Filler) The adhesive composition of the present invention may contain a filler. The inclusion of a filler allows the adhesive composition of the present invention to have suitable thixotropy, making it easier to improve shape retention after application. Particulate fillers may be used. Inorganic fillers are preferred as fillers, such as silica, talc, titanium dioxide, zinc oxide, and calcium carbonate. Among these, silica is preferred because it results in an adhesive composition with excellent ultraviolet transmittance. The filler may also be subjected to hydrophobic surface treatments such as silylation, alkylation, or epoxidation. The filler may be used alone or in combination of two or more types. The filler content is preferably 0.5 parts by mass or more and 30 parts by mass or less, more preferably 1 part by mass or more and 25 parts by mass or less, and even more preferably 2 parts by mass or more and 15 parts by mass or less, per 100 parts by mass of the adhesive composition.

[0075] In addition to the components described above, the adhesive composition of the present invention may also contain other additives such as coupling agents (silane coupling agents, titanate-based coupling agents, zirconate-based coupling agents, etc.), wax particles, ionic liquids, colorants, foaming particles, expanding particles, reactive diluents, antioxidants, and radical scavengers. The adhesive composition may be diluted with a solvent as needed. When the adhesive composition is diluted with a solvent, each amount (parts by mass, mass%) of the adhesive composition is based on the solids content, i.e., it means parts by mass, mass%, excluding the solvent.

[0076] Methods for producing the adhesive composition of the present invention include mixing moisture-curing resins (A) and (B) with other additives, such as a radical polymerizable compound (C), a photopolymerization initiator, a moisture curing accelerator, a filler, and a coupling agent, using a mixer. Examples of mixers include homodispers, homomixers, universal mixers, planetary mixers, kneaders, and three-roll mixers.

[0077] <How to use> The adhesive composition of the present invention is preferably cured and used as a cured body. The adhesive composition of the present invention is at least moisture-curable. Therefore, the adhesive composition is preferably used, for example, by placing the adhesive composition or a semi-cured adhesive composition between two adherends and bonding the two adherends with the adhesive composition (cured body) that has been cured at least by moisture.

[0078] Furthermore, the adhesive composition of the present invention preferably has photocurability, and more preferably has good photocurability by containing a radical polymerizable compound (C). In other words, the adhesive composition is preferably used as a photo-moisture curing type. Therefore, it is preferable that the adhesive composition of the present invention be photocured by light irradiation to, for example, a B-stage state (semi-cured state), and then further cured by moisture to achieve full curing before use. Here, when the adhesive composition is placed between adherends to join them, it is preferable to apply it to one adherend, then photo-cur it by light irradiation to, for example, a B-stage state, and then place the other adherend on top of the photo-cured adhesive composition to temporarily bond the adherends together with an appropriate adhesive strength. Subsequently, the adhesive composition in the B-stage state is fully cured by curing the moisture-curing resin (A) with moisture, and the adherends that were placed on top of each other via the adhesive composition are joined with sufficient adhesive strength.

[0079] The adhesive composition can be applied to the substrate, for example, by a dispenser, but is not particularly limited. The light used for photocuring is not particularly limited as long as it cures either or both of the moisture-curing resin (A) and the radical polymerizable compound (C), but ultraviolet light is preferred. When the adhesive composition is to be fully cured by moisture, it can be left in the air for a predetermined time.

[0080] The adhesive composition of the present invention is used, for example, as an adhesive for electronic components. Furthermore, it is preferable that the adhesive composition of the present invention be used as an adhesive for electronic devices, particularly portable electronic devices. The electronic component or portable electronic device in which the adhesive composition of the present invention is used may have a cured form of the adhesive composition. The adherend to which the adhesive composition is used is not particularly limited, but is preferably a component of a portable electronic device, and preferably an electronic component. The material of the adherend can be any of metal, glass, plastic, etc. The shape of the adherend is not particularly limited, and examples include film, sheet, plate, panel, tray, rod, box, housing, etc. Portable electronic devices are not particularly limited, but include mobile phones such as smartphones, digital cameras, wearable devices, portable game devices, tablet computers, notebook computers, and action cameras, with smartphones and wearable devices being preferred among these. The adhesive composition of the present invention is particularly suitable for portable electronic devices because it has good impact resistance and oil resistance.

[0081] Electronic components generally have a substrate; therefore, electronic components using the adhesive composition of the present invention may have a cured body of the adhesive composition and a substrate. Various electronic circuits and the like are generally provided on the substrate. Similarly, electronic devices such as portable electronic devices using the adhesive composition of the present invention may also have a cured body of the adhesive composition and a substrate.

[0082] In electronic components, for example, substrates may be joined to each other using the adhesive composition of the present invention as the adherend, or the substrates may be joined to other components of the electronic device (for example, a housing) using the adhesive composition of the present invention. For example, the adhesive composition of the present invention may be used inside electronic equipment, for example, to bond substrates together to obtain an assembled component. The assembled component thus obtained comprises a first substrate, a second substrate, and a cured body of the present invention, wherein at least a portion of the first substrate is bonded to at least a portion of the second substrate via the cured body. [Examples]

[0083] The present invention will be described in more detail by reference to examples, but the present invention is not limited in any way by these examples.

[0084] In this example, the adhesive composition was evaluated as follows. (Adhesive strength) As shown in Figure 1(a), a first substrate 11 measuring 90 mm x 50 mm with a thickness of 5 mm and having a circular hole 11A with a diameter of 12 mm in the center, and a second substrate 12 measuring 50 mm x 50 mm with a thickness of 5 mm were prepared. Both the first substrate 11 and the second substrate 12 were made of polycarbonate. Using a dispenser, the adhesive composition 10 was applied in a 20mm x 20mm rectangular frame shape with a width of 1mm ± 0.2mm and a height of 0.25mm ± 0.05mm, surrounding the hole 11A of the first substrate 11. Within one minute after application, ultraviolet light at 1000mJ / cm² was applied using a UV-LED (wavelength 365nm). 2 The adhesive composition 10 was photocured by irradiation. Then, the second substrate 12 was placed on top of the first substrate 11, with the centers of the first and second substrates 11 and 12 aligned, via a gap material (not shown) with a height of 0.2 mm and the adhesive composition 10. A 2 kg weight was then placed on top of the second substrate 12 for 10 seconds, thereby pressing the first and second substrates 11 and 12 together via the adhesive composition 10. After that, the 2 kg weight was removed, and the adhesive composition 10 was left to moisture cure at 25°C and 50% RH for 24 hours to obtain a sample 13 for measurement. After moisture curing, the gap material was removed from the sample 13 for measurement. In the obtained measurement sample 13, the first substrate 11 was positioned on top and the second substrate 12 on the bottom. With the first substrate 11 supported by a stainless steel jig, a rod-shaped member 14 with a circular cross-section and a diameter of 10 mm was inserted into the hole 11A. Then, as shown in Figure 1(b), the second substrate 12 was pushed vertically downward by the rod-shaped member 14 at a speed of 10 mm / min, and the stress at which the second substrate 12 peeled off from the first substrate 11 was measured and defined as the adhesive strength (adhesion strength before oil contact). The adhesive strength was evaluated according to the following evaluation criteria. AA: Adhesion strength of 4 MPa or higher A: Adhesion strength between 3 MPa and less than 4 MPa B: Adhesion less than 3 MPa

[0085] (Adhesion after contact with oil) A sample for measurement was prepared using the same procedure as described above. The entire sample was wrapped in a nonwoven fabric (product name "Kimwipe," manufactured by Nippon Paper Crecia Co., Ltd.) soaked in oleic acid, and sealed in a polyethylene bag. The bag was cured for two days at 60°C and 90% RH. After curing, the sample was washed with ethanol, and the adhesive strength was measured as described above, representing the adhesive strength after oil contact. The decrease in adhesive strength after oil contact compared to the adhesive strength before oil contact was evaluated according to the following criteria. AA: Adhesion reduction rate is 30% or less A: The reduction in adhesive strength is greater than 30% but less than or equal to 50%. B: Adhesion reduction rate greater than 50% and 70% or less C: Adhesion reduction rate is greater than 70%

[0086] (Impact resistance) As shown in Figure 2, a measurement sample 13 was prepared using the same procedure as described above, with the first substrate 11 placed on top and the second substrate 12 on the bottom, and the first substrate 11 supported by a stainless steel jig. Furthermore, a jig 16 (material: stainless steel) was prepared, having a flat plate portion 16B (20 mm x 20 mm, 5 mm thick) and a rod-shaped portion 16A (diameter 10 mm, cylindrical) connected to the center of the flat plate portion 16B. The rod-shaped portion 16A of the jig 16 was inserted into the hole 11A of the first substrate 11 as shown in Figure 2, and the jig 16 was placed upright in the center of the second substrate 12. In that state, a DuPont drop impact tester was used to repeatedly drop a 300g spherical stainless steel weight 15 vertically downwards onto the center of the flat plate 16B from a position 200mm above the flat plate 16B. The number of drops required for the weight 15 to cause the second substrate 12 to detach due to the impact was evaluated as the durability count. AA: Durability count 50 or more A: Durability: 30 or more times but less than 50 times C: Durability count is less than 30 times

[0087] (shape retention) The first and second substrates were prepared using the same procedure as when preparing the sample for measurement. The adhesive composition was applied to the first substrate and then photocured. Subsequently, without using a gap material, the second substrate was placed on top of the first substrate via the adhesive composition, ensuring that the centers of the first and second substrates aligned. A 100g weight was then placed on the second substrate for 10 seconds to press the first and second substrates together via the adhesive composition, and the weight was removed. The thickness of the adhesive composition after the weight was removed was measured and evaluated according to the following evaluation criteria. A: The thickness of the adhesive composition is 0.1 mm or more. C: The thickness of the adhesive composition is less than 0.1 mm.

[0088] The moisture-curing resins used in each example and comparative example were prepared according to the following synthesis example. <<Moisture-curing resin (1)>> [Synthesis Example 1] 100 parts by mass of polycarbonate diol (a compound represented by formula (1), where 90 mol% of R is a 3-methylpentylene group and 10 mol% is a hexamethylene group, manufactured by Kuraray Co., Ltd., trade name "Kuraraypolyol C-1090") and 0.01 parts by mass of dibutyltin dilaurate were placed in a 500 mL separable flask. The contents of the flask were mixed under vacuum (20 mmHg or less) by stirring at 80°C for 60 minutes. Then, at atmospheric pressure, 30 parts by mass of 2-methacryloyloxyethyl isocyanate (manufactured by Showa Denko Corporation, trade name "Karenz MOI") were added to the reaction product and the mixture was stirred at 100°C for 3 hours to obtain a reaction product having a polycarbonate (PC) skeleton with a methacryloyl group at one end. To the obtained reaction product, 50 parts by mass of diphenylmethane diisocyanate (manufactured by Tosoh Corporation, trade name "Millionate MT") was added as a polyisocyanate compound, and the reaction was carried out by stirring at 80°C for 3 hours to obtain a moisture-curable urethane resin (1-1) having a polycarbonate (PC) skeleton. In the moisture-curable urethane resin (1-1), the proportion of moisture-curable urethane resin (A1), in which one end has a methacryloyl group and the other end has an isocyanate group, was 80% by mass. In addition, moisture-curable urethane resin (1-1) also contained moisture-curable urethane resin (B1), in which both ends have isocyanate groups. The weight-average molecular weight of the obtained moisture-curable urethane resin (1-1) was 5000.

[0089] [Synthesis Example 2] 100 parts by mass of polyester polyol (a polyester polyol obtained mainly from adipic acid, 1,6-hexanediol, and isophthalic acid, aromatic ring concentration 15% by mass, weight-average molecular weight 1000) and 0.01 parts by mass of dibutyltin dilaurate were placed in a 500 mL separable flask. The mixture was stirred under vacuum (20 mmHg or less) at 80°C for 1 hour. Then, under atmospheric pressure, 30 parts by mass of 2-methacryloyloxyethyl isocyanate (manufactured by Showa Denko, trade name "Karenz MOI") was added, and the reaction was carried out by stirring at 100°C for 3 hours to obtain a reaction product containing a polyester skeleton with a methacryloyl group at one end. To the obtained reaction product, 50 parts by mass of diphenylmethane diisocyanate (manufactured by Tosoh Corporation, trade name "Millionate MT") was added as a polyisocyanate compound, and the reaction was carried out at 80°C for 3 hours to obtain a moisture-curable urethane resin (1-2) having a polyester skeleton. In the moisture-curable urethane resin (1-2), the proportion of moisture-curable urethane resin (A1), in which one end has a methacryloyl group and the other end has an isocyanate group, was 80% by mass. Moisture-curable urethane resin (1-2) also contained moisture-curable urethane resin (B1), in which both ends have isocyanate groups. The weight-average molecular weight of the obtained moisture-curable urethane resin (1-2) was 3000.

[0090] <<Moisture-curing resin (2)>> [Synthesis Example 3] 100 parts by mass of polycarbonate diol (a compound represented by formula (1), where 90 mol% of R is a 3-methylpentylene group and 10 mol% is a hexamethylene group, manufactured by Kuraray Co., Ltd., trade name "Kuraraypolyol C-1090") as the polyol compound and 0.01 parts by mass of dibutyltin dilaurate were placed in a 500 mL separable flask. The flask was mixed under vacuum (20 mmHg or less) by stirring at 100 °C for 30 minutes. Then, the pressure was reduced to atmospheric pressure, and 50 parts by mass of diphenylmethane diisocyanate (manufactured by Tosoh Corporation, trade name "Millionate MT") as the polyisocyanate compound was added and the mixture was reacted by stirring at 80 °C for 3 hours to obtain a moisture-curable urethane resin (2-1) having a polycarbonate (PC) backbone and isocyanate groups at both ends. The weight-average molecular weight of the obtained moisture-curable urethane resin (2-1) was 6000.

[0091] [Synthesis Example 4] 100 parts by mass of polyester polyol (a polyester polyol obtained mainly from adipic acid, 1,6-hexanediol, and isophthalic acid, aromatic ring concentration 15% by mass, weight-average molecular weight 1000) and 0.01 parts by mass of dibutyltin dilaurate were placed in a 500 mL separable flask. The mixture was stirred under vacuum (20 mmHg or less) at 100 °C for 30 minutes. Then, under atmospheric pressure, 52.5 parts by mass of diphenylmethane diisocyanate (manufactured by Tosoh Corporation, trade name "Millionate MT") was added as the polyisocyanate compound, and the mixture was reacted by stirring at 80 °C for 3 hours to obtain a moisture-curable urethane resin (2-2) containing a polyester skeleton with isocyanate groups at both ends. The weight-average molecular weight of the obtained moisture-curable urethane resin (2-2) was 1500.

[0092] The components other than the moisture-curing urethane resin used in each example and comparative example were as follows: (Radical polymerizable compounds) Imide ring-containing acrylate: Manufactured by Toagosei Co., Ltd., product name "M-140", N-acryloyloxyethylhexahydrophthalimide, monofunctional. Aromatic ring-containing acrylate: Manufactured by Kyoeisha Chemical Co., Ltd., product name "Light Acrylate PO-A", phenoxyethyl acrylate, monofunctional. Aliphatic acrylate: Manufactured by Daicel Ornex, product name "IBOA-B", isovonyl acrylate, monofunctional. Filler: Trimethylsilylated silica, manufactured by Nippon Aerosil Co., Ltd., product name "R812", primary particle size 7 nm Photopolymerization initiator: 2-benzyl-2-dimethylamino-1-(4-morpholinophenyl)-butanone-1, manufactured by BASF, trade name "IRGACURE 369" Other additives: radical scavengers, antioxidants, and moisture-curing catalysts.

[0093] [Examples 1-6, Comparative Examples 1-3] According to the mixing ratios listed in Table 1, each material was stirred at a temperature of 50°C using a planetary agitator (Sinky Co., Ltd., "Awatori Rentaro"), and then uniformly mixed at a temperature of 50°C using a ceramic three-roll roller to obtain the adhesive compositions of Examples 1-6 and Comparative Examples 1-3.

[0094] [Table 1]

[0095] As shown in Table 1, in each example, the adhesive composition contained a moisture-curable resin (A) having a specific structure and a moisture-curable resin (B), resulting in high impact resistance while maintaining good oil resistance and high adhesive strength even after contact with oil. Furthermore, as shown in Examples 3 to 5, the adhesive composition contained a radical polymerizable compound (C) in addition to moisture-curable resins (A) and (B), resulting in good shape retention, and a certain distance could be maintained between adherends by the cured product formed from the adhesive composition. In contrast, in Comparative Examples 1 to 3, the adhesive compositions were able to secure an adhesive strength above a certain level by containing moisture-curing resin (B), but because they did not contain moisture-curing resin (A), they were unable to improve impact resistance while maintaining good oil resistance.

Claims

1. A moisture-curing resin (A) having at least one of a polycarbonate skeleton and a polyester skeleton, and having isocyanate groups and (meth)acryloyl groups, A moisture-curing resin (B) having an isocyanate group and not having a (meth)acryloyl group, The moisture-curing resin (A) has one isocyanate group in one molecule, An adhesive composition in which the moisture-curable resin (A) is contained in an amount of 0.1 parts by mass or more and 30 parts by mass or less, based on 100 parts by mass of the total amount of the moisture-curable resin and the radical polymerizable compound.

2. The adhesive composition according to claim 1, wherein the moisture-curing resin (B) has at least one of a polycarbonate skeleton and a polyester skeleton.

3. The adhesive composition according to claim 1 or 2, wherein the moisture-curing resin (B) has a polycarbonate skeleton.

4. The adhesive composition according to any one of claims 1 to 3, wherein the moisture-curing resin (B) has isocyanate groups at both ends.

5. The adhesive composition according to any one of claims 1 to 4, wherein the moisture-curing resin (A) has a polycarbonate skeleton.

6. The adhesive composition according to any one of claims 1 to 5, wherein the moisture-curable resin (A) has an aromatic isocyanate group.

7. The adhesive composition according to any one of claims 1 to 6, further comprising a radical polymerizable compound (C) that does not contain an isocyanate group.

8. The adhesive composition according to claim 7, wherein the radical polymerizable compound (C) contains at least one selected from the group consisting of radical polymerizable compounds having an aromatic ring and radical polymerizable compounds having an imide ring.

9. An adhesive for electronic components comprising the adhesive composition according to any one of claims 1 to 8.

10. An adhesive for portable electronic devices comprising the adhesive composition according to any one of claims 1 to 8.

11. A cured body of the adhesive composition according to any one of claims 1 to 8.

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