Adhesive composition, adhesive for electronic parts, and adhesive for portable electronic device

Abstract

The adhesive composition of the present application contains: a moisture-curable resin (A) having at least either a polycarbonate skeleton or a polyester skeleton, and having an isocyanate group and a (meth)acryl group; and a moisture-curable resin (B) having an isocyanate group, and not having a (meth)acryl group.

Description

Technical Field

[0001] This invention relates to adhesive compositions, adhesives for electronic components, and adhesives for portable electronic devices. Background Technology

[0002] In the past, moisture-curing adhesives containing moisture-curing resins that cure using external moisture have been widely used. For example, Patent Document 1 discloses a moisture-curing adhesive with an isocyanate-terminated prepolymer as its main component. This isocyanate-terminated prepolymer is obtained by reacting a polyol containing a polycarbonate diol with a specific structure and a polyisocyanate compound at an isocyanate group / hydroxyl group molar ratio of 1.3 to 3.5.

[0003] The moisture-curing adhesive disclosed in Patent Document 1 can be used in clothing applications. It has excellent resistance to sweat degradation and hydrolysis, and can improve softness. In particular, it exhibits excellent resistance to degradation of higher fatty acids, which are one of the components of sweat.

[0004] In recent years, the application of moisture-curing adhesives in various applications has been studied. For example, as disclosed in Patent Document 2, applications in electronic devices such as display devices and semiconductor chips are also being studied.

[0005] Existing technical documents

[0006] Patent documents

[0007] Patent Document 1: Japanese Patent Application Publication No. 2003-313531

[0008] Patent Document 2: International Publication No. 2020 / 149377 Summary of the Invention

[0009] The problem that the invention aims to solve

[0010] However, in recent years, portable electronic devices such as smartphones and tablet computers have become increasingly widespread. Additionally, wearable devices are also becoming more common. Smartphones, wearable devices, and other portable electronic devices have prolonged contact with the skin. Therefore, adhesives used in portable electronic devices come into frequent contact with sebum, sweat, and chemicals contained in skincare products such as cosmetics and sunscreens, sometimes requiring oil resistance.

[0011] In addition, portable electronic devices are often dropped during use. Therefore, adhesives used in portable electronic devices mostly need to have high impact resistance to prevent parts from falling off when dropped.

[0012] For example, as described in Patent Document 1, a certain degree of oil resistance can be ensured by using a polyol with a specific structure such as polycarbonate in the polyol used in moisture-curing resins. However, in conventional moisture-curing adhesives, it is difficult to ensure both oil resistance and high impact resistance.

[0013] Therefore, the objective of this invention is to achieve a balance between high oil resistance and high impact resistance in adhesive compositions with moisture-curing properties.

[0014] Methods for solving problems

[0015] The inventors of this application, through in-depth research, discovered that by using at least two moisture-curing resins having specific structures, the above-mentioned problems can be solved, thereby completing the following invention. That is, the present invention provides the following [1] to

[26] .

[0016] [1] An adhesive composition comprising:

[0017] A moisture-curing resin (A), wherein the moisture-curing resin (A) has at least one of a polycarbonate backbone and a polyester backbone, and has isocyanate groups and (meth)acryloyl groups; and

[0018] Moisture-curing resin (B), wherein the moisture-curing resin (B) has isocyanate groups and does not have (meth)acryloyl groups.

[0019] [2] According to the adhesive composition described in [1] above, the moisture-curing resin (B) has at least one of a polycarbonate backbone and a polyester backbone.

[0020] [3] According to the adhesive composition described in [1] or [2] above, the moisture-curing resin (B) has a polycarbonate backbone.

[0021] [4] According to any one of the adhesive compositions described in [1] to [3] above, the moisture-curing resin (B) has isocyanate groups at both ends.

[0022] [5] The moisture-curing resin (A) of any one of the adhesive compositions described in any one of [1] to [4] above has a polycarbonate backbone.

[0023] [6] The adhesive composition according to any one of [1] to [5] above, wherein the moisture-curing resin (A) has an aromatic isocyanate group.

[0024] [7] The adhesive composition according to any one of [1] to [6] above further comprises a free radical polymerizable compound (C) that does not contain an isocyanate group.

[0025] [8] According to the adhesive composition described above [7], the free radical polymerizable compound (C) contains at least one selected from the group consisting of free radical polymerizable compounds having an aromatic ring and free radical polymerizable compounds having an imide ring.

[0026] [9] According to the adhesive composition described in [7] or [8] above, the free radical polymerizable compound (C) contains a compound having a (meth)acryloyl group.

[0027]

[10] According to any one of the adhesive compositions described in [7] to [9] above, the free radical polymerizable compound (C) contains other free radical polymerizable compounds besides free radical polymerizable compounds having aromatic rings and free radical polymerizable compounds having imide rings.

[0028]

[11] According to the adhesive composition described in

[10] above, the other free radical polymerizable compound comprises at least one selected from the group consisting of aliphatic urethane (meth)acrylates and (meth)acrylate compounds.

[0029]

[12] In any of the adhesive compositions described in [7] to

[11] above, the content of the free radical polymeric compound (C) is 5 to 50 parts by mass relative to 100 parts by mass of the total mass of the moisture-curing resin and the free radical polymeric compound.

[0030]

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

[12] above further contains a photopolymerization initiator.

[0031]

[14] According to any one of the adhesive compositions described in [1] to

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

[0032]

[15] In any one of the adhesive compositions described above [1] to

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

[0033]

[16] According to the adhesive composition described above

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

[0034]

[17] According to any one of the adhesive compositions described above [1] to

[16] , the content of the moisture-curing resin (A) is 0.1 to 30 parts by mass relative to 100 parts by mass of the total amount of the moisture-curing resin and the free radical polymerizable compound.

[0035]

[18] In any one of the adhesive compositions described above [1] to

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

[0036]

[19] According to the adhesive composition described above

[18] , the moisture-curing polyurethane resin (B1) is a resin obtained by reacting a polyol compound and a polyisocyanate compound.

[0037]

[20] According to any one of the adhesive compositions described above [1] to

[19] , the content of the moisture-curing resin (B) is 30 parts by mass to 99.9 parts by mass relative to 100 parts by mass of the total amount of the moisture-curing resin and the free radical polymerizable compound.

[0038]

[21] The adhesive composition according to any one of [1] to

[20] above further contains a filler.

[0039]

[22] An adhesive for electronic components, which is formed from the adhesive composition described in any one of [1] to

[21] above.

[0040]

[23] An adhesive for portable electronic devices, which is formed from the adhesive composition described in any one of [1] to

[21] above.

[0041]

[24] A cured body, which is a cured body of the adhesive composition described in any one of [1] to

[21] above.

[0042]

[25] Application of the adhesive composition described in any one of [1] to

[21] above to electronic components.

[0043]

[26] The application of the adhesive composition described in any one of [1] to

[21] above to portable electronic devices.

[0044] Invention Effects

[0045] According to the present invention, it is possible to achieve both high oil resistance and high impact resistance in adhesive compositions with moisture curing properties. Attached Figure Description

[0046] [ Figure 1 This is a schematic diagram illustrating the method for evaluating adhesive strength. Figure 1 (a) is a top view. Figure 1 (b) is a side view.

[0047] [ Figure 2 This is a schematic side view illustrating the method for evaluating impact resistance. Detailed Implementation

[0048] <Adhesive Composition>

[0049] The adhesive composition of the present invention contains a moisture-curing resin (A) and a moisture-curing resin (B).

[0050] The following is a detailed description of each moisture-curing resin.

[0051] [Moisture-curing resin (A)]

[0052] The moisture-curing resin (A) has at least one of a polycarbonate backbone and a polyester backbone, and has an isocyanate group and a (meth)acryloyl group.

[0053] The adhesive composition of the present invention, by combining a moisture-curing resin (A) having the above-described structure with a moisture-curing resin (B) having the structure described later, ensures a certain level of adhesion and achieves a balance between high oil resistance and high impact resistance. Furthermore, the adhesive composition, by having both moisture-curing resin (A) and moisture-curing resin (B), possesses moisture-curing properties and can be used as a moisture-curing adhesive.

[0054] It should be noted that in this specification, "(meth)acryloyl" refers to acryloyl or methacryloyl, and other similar terms are the same.

[0055] Moisture-curing resin (A) may have either a polycarbonate backbone or a polyester backbone in one molecule, or it may contain both a polycarbonate backbone and a polyester backbone in one molecule. In addition, moisture-curing resin (A) may be a combination of a moisture-curing resin having a polycarbonate backbone and a moisture-curing resin having a polyester backbone.

[0056] As for the moisture-curing resin (A), from the viewpoint of flexibility, a moisture-curing resin with a polyester backbone can be used, but a moisture-curing resin with a polycarbonate backbone is preferred. By using a moisture-curing resin with a polycarbonate backbone, oil resistance is improved, and the adhesive strength is easily maintained well even after contact with oil.

[0057] As the moisture-curing resin (A), it is preferable to use the moisture-curing resin (A) having a polycarbonate backbone alone, but as described above, it may also be used in combination with the moisture-curing resin (A) having a polyester backbone. When the moisture-curing resin (A) contains the moisture-curing resin (A) having a polycarbonate backbone, it may contain preferably 50% or more by mass, more preferably 75% to 100% by mass of the moisture-curing resin (A) having a polycarbonate backbone.

[0058] As will be described later, the polycarbonate backbone and polyester backbone in the moisture-curing resin (A) are preferably derived from polyol compounds. Therefore, the polycarbonate backbone can be derived from polycarbonate polyols, and the polyester backbone can be derived from polyester polyols.

[0059] Furthermore, the moisture-curing resin (A) may have one or more isocyanate groups per molecule, but preferably one isocyanate group per molecule. Additionally, the moisture-curing resin (A) may have either or both aliphatic and aromatic isocyanate groups, but preferably aromatic isocyanate groups. By having aromatic isocyanate groups, the moisture-curing resin (A) exhibits improved oil resistance, readily maintaining good adhesion even after contact with oils. The moisture-curing resin (A) preferably has isocyanate groups at the ends.

[0060] It should be noted that aromatic isocyanate groups are isocyanate groups directly bonded to aromatic rings, while aliphatic isocyanate groups are isocyanate groups formed by isocyanate groups directly bonded to aliphatic carbon atoms.

[0061] Aromatic isocyanate groups are isocyanate groups derived from aromatic isocyanate compounds, details of which are described later. Aliphatic isocyanate groups are isocyanate groups derived from aliphatic isocyanate compounds, details of which are described later.

[0062] The (meth)acryloyl group of the moisture-curing resin (A) can be derived from compounds containing (meth)acryloyl groups described later. The moisture-curing resin (A) preferably has a (meth)acryloyl group at its terminal. The (meth)acryloyl group of the moisture-curing resin (A) can be reacted by photocuring as described later, but it is not necessarily required to undergo photocuring. That is, the moisture-curing resin (A) can react with itself through photocuring, or it can react with the free radical polymerizable compound (C) described later, or it may not react at all.

[0063] From the viewpoint of impact resistance, the moisture-curing resin (A) preferably has an isocyanate group at one end and a (meth)acryloyl group at the other end. It should be noted that, in this specification, "end" refers to the end of the main chain.

[0064] (Moisture-curing polyurethane resin (A1))

[0065] The moisture-curing resin (A) is preferably a moisture-curing polyurethane resin (A1). Therefore, the moisture-curing resin (A) preferably has urethane bonds in addition to isocyanate groups and (meth)acryloyl groups. By using a moisture-curing polyurethane resin (A1) as the moisture-curing resin (A), oil resistance and other properties are easily improved. The following will describe in more detail the case where the moisture-curing resin (A) is a moisture-curing polyurethane resin (A1).

[0066] The moisture-curing polyurethane resin (A1) is preferably a resin obtained by reacting a polyol compound, a polyisocyanate compound, and a compound having a (meth)acrylyl group. The compound having a (meth)acrylyl group may have either a hydroxyl group or an isocyanate group, but from the viewpoint that (meth)acrylyl groups can be easily introduced into the resin (A1), an isocyanate group is preferred.

[0067] The reactions of the aforementioned polyol compounds, polyisocyanate compounds, and compounds having (meth)acryloyl groups are generally carried out in the range of [NCO] / [OH] = 2.0 to 2.5, where the molar ratio of hydroxyl (OH) to isocyanate (NCO) groups in these compounds is [NCO] / [OH] = 2.0 to 2.5.

[0068] Moisture-curing polyurethane resin (A1) can be obtained by reacting a polyol compound with a polyisocyanate compound, and further reacting the resulting reaction product with a compound having isocyanate or hydroxyl groups and (meth)acryloyl groups. Alternatively, it can be obtained by reacting a polyol compound with a compound having isocyanate and (meth)acryloyl groups, and then reacting the resulting reaction product with the polyisocyanate compound. Furthermore, it can be obtained by reacting a polyisocyanate compound with a compound having hydroxyl and (meth)acryloyl groups, and then reacting the resulting reaction product with the polyol compound. Moreover, moisture-curing polyurethane resin (A1) can also be obtained by reacting a polyol compound, a polyisocyanate compound, and a compound having isocyanate or hydroxyl and (meth)acryloyl groups simultaneously and in parallel.

[0069] Furthermore, in the synthesis of the moisture-curing polyurethane resin (A1), at least a portion of the moisture-curing polyurethane resin (B1) described later can also be synthesized simultaneously. Examples of such a moisture-curing polyurethane resin (B1) include polyurethane resins having isocyanate groups at both ends. Additionally, in the synthesis of the moisture-curing polyurethane resin (A1), urethane (meth)acrylates that do not have isocyanate groups but have (meth)acryloyl groups can also be synthesized.

[0070] The polyol compound used as a raw material for moisture-curing polyurethane resin (A1) has two or more hydroxyl groups in one molecule. Either polycarbonate polyol or polyester polyol can be used as the polyol compound.

[0071] As a polycarbonate polyol, polycarbonate diol is preferred. Specific examples of polycarbonate diols include compounds represented by the following formula (1).

[0072]

[0073] In equation (1), R is a divalent hydrocarbon group with 4 to 16 carbon atoms, and n is an integer from 2 to 500.

[0074] In formula (1), R is preferably an aliphatic saturated hydrocarbon group. By making R an aliphatic saturated hydrocarbon group, heat resistance and flexibility are easily improved. In addition, it is less prone to yellowing due to heat degradation, and weather resistance is also improved. R composed of aliphatic saturated hydrocarbon groups can have a chain structure or a ring structure, but a chain structure is preferred. In addition, R with a chain structure can be any shape, such as straight chain or branched chain.

[0075] n is preferably 5 to 200, more preferably 10 to 150, and even more preferably 20 to 50.

[0076] Furthermore, the R contained in the polycarbonate polyol constituting the moisture-curing polyurethane resin (A1) can be a single type or two or more types used in combination. When two or more types are used in combination, it is preferable that at least a portion of them are chain-like aliphatic saturated hydrocarbon groups with 6 or more carbon atoms. In addition, it is preferable that one molecule contains two or more types of R, and more preferably two or three types of R in one molecule.

[0077] The chain-like aliphatic saturated hydrocarbon group with 6 or more carbon atoms preferably has 6 to 12 carbon atoms, more preferably 6 to 10 carbon atoms, and even more preferably 6 to 8 carbon atoms.

[0078] Specific examples of R can be linear groups such as 1,4-butylene, pentylene, 1,6-hexylene, 1,7-heptene, 1,8-octylene, 1,9-nonylene, and 1,10-decylene, or branched groups such as methylpentylene (e.g., 3-methylpentylene) and methyl-1,8-octylene. Multiple Rs in a molecule can be identical or different. Furthermore, from the viewpoint of achieving an elastic modulus of a certain value or higher, R preferably contains branched aliphatic saturated hydrocarbon groups; from the viewpoint of weather resistance, R preferably contains linear aliphatic saturated hydrocarbon groups. Rs in polycarbonate polyols can also combine both branched and linear Rs.

[0079] It should be noted that polycarbonate polyols can be used alone or in combination of two or more.

[0080] Examples of polyester polyols include, for instance, polyester polyols obtained by reacting polycarboxylic acids with polyols, and poly-ε-caprolactone polyols obtained by ring-opening polymerization of ε-caprolactone. Polyester diols are preferred.

[0081] Examples of polycarboxylic acids used as raw materials for polyester polyols include, for instance, binary aromatic carboxylic acids such as terephthalic acid, isophthalic acid, 1,5-naphthalenedicarboxylic acid, and 2,6-naphthalenedicarboxylic acid; binary aliphatic carboxylic acids such as succinic acid, glutaric acid, adipic acid, pimelic acid, octanoic acid, azelaic acid, sebacic acid, decamethyldicarboxylic acid, and dodecamethyldicarboxylic acid; trivalent or higher aromatic carboxylic acids such as trimellitic acid, pyromellitic acid, pyromellitic tetracarboxylic acid, and naphthalenedicarboxylic acid; and trivalent or higher aliphatic carboxylic acids such as cyclohexanetricarboxylic acid and hexanetricarboxylic acid. These polycarboxylic acids can be used alone or in combination of two or more.

[0082] Examples of polyols that can be used as raw materials for polyester polyols include ethylene glycol, 1,2-propanediol, 1,3-propanediol, 1,4-butanediol, neopentyl glycol, 1,5-pentanediol, 1,6-hexanediol, diethylene glycol, and cyclohexanediol.

[0083] In moisture-curing polyurethane resin (A1), as a polyol compound, one type can be used alone, or two or more types can be used in combination.

[0084] It should be noted that, in this invention, a polycarbonate backbone can be introduced into the moisture-curing polyurethane resin (A1) by using a polycarbonate polyol in the polyol compound that serves as a raw material for the moisture-curing polyurethane resin (A1), thereby producing a moisture-curing polyurethane resin (A1) with a polycarbonate backbone. Similarly, a polyester polyol can be used in the polyol compound that serves as a raw material for the moisture-curing polyurethane resin (A1), thereby introducing a polyester backbone into the moisture-curing polyurethane resin (A1), thereby producing a moisture-curing polyurethane resin (A1) with a polyester backbone.

[0085] Furthermore, the moisture-curing polyurethane resin (A1) can also be made by using both polycarbonate polyol and polyester polyol in the polyol compound that serves as the raw material for the moisture-curing polyurethane resin (A1), thereby introducing both a polycarbonate backbone and a polyester backbone into the moisture-curing polyurethane resin (A1). That is, the moisture-curing polyurethane resin (A1) can be a moisture-curing polyurethane resin (A1) having both a polycarbonate backbone and a polyester backbone in one molecule. It should be noted that, in this specification, the moisture-curing polyurethane resin (A1) having a polycarbonate backbone also includes a moisture-curing polyurethane resin (A1) containing both a polycarbonate backbone and a polyester backbone. Other similar terms are also used.

[0086] Polyisocyanate compounds that serve as raw materials for moisture-curing polyurethane resins (A1) have two or more isocyanate groups in one molecule, but preferably two isocyanate groups. Examples of polyisocyanate compounds include aromatic polyisocyanate compounds and aliphatic polyisocyanate compounds.

[0087] Examples of aromatic polyisocyanate compounds include diphenylmethane diisocyanate, liquid modified diphenylmethane diisocyanate, toluene diisocyanate, and naphthalene-1,5-diisocyanate. Aromatic polyisocyanate compounds can be compounds formed by polymerizing these compounds, or they can be polymerized MDI, etc. Diphenylmethane diisocyanate is preferably a preferred aromatic polyisocyanate compound.

[0088] Examples of aliphatic polyisocyanate compounds include, for example, 1,6-hexanediisocyanate, trimethyl-1,6-hexanediisocyanate, lysine diisocyanate, norbornene diisocyanate, transcyclohexane-1,4-diisocyanate, isophorone diisocyanate, hydrogenated phenylene diisocyanate, hydrogenated diphenylmethane diisocyanate, cyclohexane diisocyanate, bis(isocyanatomethyl)cyclohexane, and dicyclohexylmethane diisocyanate. Aliphatic polyisocyanate compounds can also be compounds formed by polymerizing these compounds.

[0089] Polyisocyanate compounds can be used alone or in combination of two or more.

[0090] In this invention, in the synthesis of the moisture-curing polyurethane resin (A1), if an aromatic polyisocyanate compound is used, the moisture-curing resin (A) contains aromatic isocyanate groups; if an aliphatic polyisocyanate compound is used, the moisture-curing resin (A) contains aliphatic isocyanate groups. Therefore, as the polyisocyanate compound, an aromatic polyisocyanate compound is preferred.

[0091] As described above, the compound having a (meth)acrylyl group that serves as a raw material for moisture-curing polyurethane resin (A1) may contain either an isocyanate group or a hydroxyl group, but is preferably a compound having both an isocyanate group and a (meth)acrylyl group. Examples of compounds having both an isocyanate group and a (meth)acrylyl group include, for example, the compound represented by the following formula (2).

[0092]

[0093] In equation (2), R 1 R represents hydrogen or methyl. 2 It represents a divalent saturated hydrocarbon group with 1 to 10 carbon atoms that can have ether bonds.

[0094] Examples of compounds having an isocyanate group and a (meth)acryloyl group include 2-(meth)acryloyloxyethyl ester isocyanate and 2-(meth)acryloyloxyethoxyethyl ester isocyanate.

[0095] Compounds containing hydroxyl and (meth)acryloyl groups that can be used as raw materials for moisture-curing polyurethane resins (A1) include hydroxyethyl (meth)acrylate, hydroxypropyl (meth)acrylate, hydroxybutyl (meth)acrylate, hydroxybutyl (meth)acrylate, and hydroxyalkyl (meth)acrylates.

[0096] Alternatively, compounds with (meth)acryloyl groups, obtained by reacting these compounds having hydroxyl and (meth)acryloyl groups with various diisocyanate compounds in a ratio of isocyanate group / hydroxyl (molar ratio) of 2, can also be used as raw materials for moisture-curing polyurethane resins (A1).

[0097] The weight-average molecular weight of the moisture-curing 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. If the weight-average molecular weight is above the lower limit, the crosslinking density will not become excessively high during curing, and the flexibility after curing will easily increase. In addition, for example, in the semi-cured state after light curing and before moisture curing, it has a certain hardness, which easily ensures excellent shape retention. Furthermore, by making the weight-average molecular weight below the upper limit, the adhesive composition easily has moderate fluidity before curing, for example, even at room temperature (e.g., 25°C), and the coatability becomes good.

[0098] It should be noted that, in this specification, the weight-average molecular weight is a value determined by gel permeation chromatography (GPC) and converted to polystyrene. Shodex LF-804 (manufactured by Showa Denko) is an example of a column used for determining the weight-average molecular weight converted to polystyrene using GPC. Tetrahydrofuran is an example of a solvent used in GPC.

[0099] The content of the moisture-curing resin (A) in the adhesive composition is, for example, 0.1 to 30 parts by mass relative to 100 parts by mass of the total mass of the moisture-curing resin and the free radical polymerizable compound. By keeping the content of component (A) within the above range, the adhesive composition readily exhibits good oil resistance and adhesion, and improves impact resistance. From these viewpoints, the above-mentioned content of the moisture-curing resin (A) is preferably 0.5 to 25 parts by mass, more preferably 0.7 to 15 parts by mass, and even more preferably 1 to 10 parts by mass.

[0100] It should be noted that, in this specification, the total amount of moisture-curing resin and free radical polymerizable compound, when excluding the free radical polymerizable compound (C) component, refers to the total content of moisture-curing resin.

[0101] [Moisture-curing resin (B)]

[0102] The moisture-curing resin (B) in this invention is a resin having isocyanate groups but not (meth)acryloyl groups. The adhesive composition, by having the moisture-curing resin (B), can impart suitable adhesive properties to the adhesive composition.

[0103] The moisture-curing resin (B) preferably has at least one of a polycarbonate backbone and a polyester backbone. By having any of these backbones, the moisture-curing resin (B) can easily achieve a balance between oil resistance and impact resistance.

[0104] The moisture-curing resin (B) having at least one of a polycarbonate backbone and a polyester backbone may have either a polycarbonate backbone or a polyester backbone in one molecule, or may contain both a polycarbonate backbone and a polyester backbone in one molecule. Furthermore, the moisture-curing resin (B) may also be a combination of a moisture-curing resin having a polycarbonate backbone and a moisture-curing resin having a polyester backbone.

[0105] Furthermore, the moisture-curing resin (B) is more preferably provided with a polycarbonate backbone. By using a moisture-curing resin (B) with a polycarbonate backbone, the adhesive composition can easily achieve a balance between high oil resistance and high impact resistance. In particular, the oil resistance becomes excellent, and high adhesion is easily ensured even after contact with oil.

[0106] As the moisture-curing resin (B), it is preferable to use the moisture-curing resin (B) having a polycarbonate backbone alone, but as described above, it may also be used in combination with the moisture-curing resin (B) having a polyester backbone. When the moisture-curing resin (B) contains the moisture-curing resin (B) having a polycarbonate backbone, it may contain preferably 50% by mass or more, more preferably 75% by mass to 100% by mass of the moisture-curing resin (B) having a polycarbonate backbone.

[0107] As will be described later, the polycarbonate backbone and polyester backbone in the moisture-curing resin (B) are preferably derived from polyol compounds. Therefore, the polycarbonate backbone can be derived from polycarbonate polyols, and the polyester backbone can be derived from polyester polyols.

[0108] Furthermore, the moisture-curing resin (B) may have one or more isocyanate groups per molecule, but preferably two or more isocyanate groups per molecule, and more preferably two isocyanate groups. Additionally, the moisture-curing resin (B) may have any one or both of aliphatic and aromatic isocyanate groups, but preferably aromatic isocyanate groups. By having aromatic isocyanate groups, the moisture-curing resin (B) exhibits improved oil resistance, readily maintaining good adhesion even after contact with oil.

[0109] Aromatic isocyanate groups are derived from the isocyanate groups of aromatic isocyanate compounds, while aliphatic isocyanate groups are derived from the isocyanate groups of aliphatic isocyanate compounds.

[0110] The moisture-curing resin (B) preferably has isocyanate groups at both ends, more preferably has isocyanate groups at both ends. By having isocyanate groups at both ends, the moisture-curing resin (B) can easily achieve high molecular weight through moisture curing, thus ensuring high adhesion. Furthermore, from the viewpoint of oil resistance, the moisture-curing resin (B) is further preferably equipped with aromatic isocyanate groups at both ends.

[0111] (Moisture-curing polyurethane resin (B1))

[0112] The moisture-curing resin (B) is preferably a moisture-curing polyurethane resin (B1). Therefore, the moisture-curing resin (B) preferably has urethane bonds in addition to isocyanate groups. By using a moisture-curing polyurethane resin (B1) as the moisture-curing resin (B), oil resistance and other properties are easily improved. The following will describe in more detail the case where the moisture-curing resin (B) is a moisture-curing polyurethane resin (B1).

[0113] Moisture-curing polyurethane resin (B1) may have one isocyanate group in one molecule or two or more isocyanate groups, but as mentioned above, it is more preferable to have isocyanate groups at both ends of the main chain.

[0114] Moisture-curing polyurethane resin (B1) can be obtained by reacting polyol compounds with polyisocyanate compounds. The reaction between polyol compounds and polyisocyanate compounds is usually carried out in the range of [NCO] / [OH] = 2.0 to 2.5, based on the molar ratio of hydroxyl groups (OH) in the polyol compound to isocyanate groups (NCO) in the polyisocyanate compound.

[0115] As the polyol compound used in the moisture-curing polyurethane resin (B1), known polyol compounds commonly used in the manufacture of polyurethane can be used. From the viewpoint of balancing oil resistance and impact resistance, polyester polyols and polycarbonate polyols are preferred, with polycarbonate polyols being the most preferred.

[0116] It should be noted that, in this invention, a polycarbonate backbone can be introduced into the moisture-curing polyurethane resin (B1) by using a polycarbonate polyol in the polyol compound that serves as a raw material for the moisture-curing polyurethane resin (B1), thereby producing a moisture-curing polyurethane resin (B1) with a polycarbonate backbone. Alternatively, a polyester polyol can be used in the polyol compound that serves as a raw material for the moisture-curing polyurethane resin (B1), thereby introducing a polyester backbone into the moisture-curing polyurethane resin (B1), thus producing a moisture-curing polyurethane resin (B1) with a polyester backbone. Furthermore, both a polycarbonate backbone and a polyester backbone can be introduced into a single molecule.

[0117] The polycarbonate polyols and polyester polyols used as raw materials for moisture-curing polyurethane resin (B1) can be the same substances listed as raw materials for moisture-curing polyurethane resin (A1), and their descriptions are omitted here.

[0118] The polyisocyanate compound used as a raw material for the moisture-curing polyurethane resin (B1) has two or more isocyanate groups in one molecule, preferably two isocyanate groups. Examples of polyisocyanate compounds include aromatic polyisocyanate compounds and aliphatic polyisocyanate compounds. As aromatic or aliphatic polyisocyanate compounds, compounds listed as raw materials for the moisture-curing polyurethane resin (A1) can be used, and their descriptions are the same, therefore their descriptions are omitted. As with the moisture-curing polyurethane resin (B1), aromatic polyisocyanate compounds are preferred, and diphenylmethane diisocyanate is preferred.

[0119] As a moisture-curing resin (B), it may also be a resin having an organosilicon group as shown in formula (3) in addition to the isocyanate group.

[0120]

[0121] In equation (3), R 3 and R 4 Each is independently a hydrogen atom, an alkyl group having 1 to 5 carbon atoms, or an aryl group, each R 3 and R 4 They can be the same or different. x represents an integer from 0 to 2.

[0122] In the above equation (3), in R 3 and R 4 When each component is an aryl group, examples of such aryl groups include phenyl, naphthyl, and 2-methylphenyl. In formula (3) above, from the viewpoint of exhibiting superior adhesion, x is preferably 1 or 2.

[0123] It should be noted that the case where x is 0 in the above equation (3) means that the silicon atom does not interact with R. 3 The atoms or groups represented are bonded to 3 -OR 4 The bonding situation.

[0124] Among the groups represented by formula (3), from the viewpoint of improving adhesion, R 3 and R 4 Preferably, it is an alkyl group having 1 to 5 carbon atoms, more preferably either methyl or ethyl.

[0125] When the moisture-curing resin (B) contains the aforementioned organosilicon group, the moisture-curing resin (B) is preferably a moisture-curing polyurethane resin (B1), and therefore, it is preferable to have urethane bonds in addition to isocyanate groups and organosilicon groups. Furthermore, when the moisture-curing resin (B) contains the aforementioned organosilicon group, it is preferable to have both an organosilicon group and an isocyanate group at each end.

[0126] The moisture-curing polyurethane resin (B1) having an organosilicon alkyl group can be obtained as follows: a polyol compound is reacted with a polyisocyanate compound to obtain a compound having urethane bonds and isocyanate groups, and this compound is then reacted with a compound having reactive functional groups and groups represented by formula (3). It should be noted that the above-mentioned "reactive functional groups" refer to groups that can react with the above-mentioned compounds having urethane bonds and isocyanate groups, preferably groups that can react with isocyanate groups.

[0127] Polyol compounds and polyisocyanate compounds are as described above.

[0128] Examples of compounds having the reactive functional groups and the groups represented by formula (3) include, for example, 3-mercaptopropyltrimethoxysilane, 3-mercaptopropyltriethoxysilane, 3-epoxypropoxypropyltrimethoxysilane, 3-epoxypropoxypropyltriethoxysilane, 2-(3,4-epoxycyclohexyl)ethyltrimethoxysilane, 3-epoxypropoxypropylmethyldiethoxysilane, 3-aminopropyltrimethoxysilane, 3-aminopropyltriethoxysilane, 3-(2-aminoethyl)aminopropyltrimethoxysilane, 3-(2-aminoethyl)aminopropyltrieth ...ethyl)aminopropyltriethoxysilane, 3-(2-aminoethyl)aminoethyl)aminopropyltriethoxysilane, 3-(2-aminoethyl)aminoethyl)aminoethyl)aminoethyl)aminoethyl)triethoxysilane, 3-(2-aminoethyl)aminoethyl)aminoethyl)aminoethyl)aminoethyl)aminoethyl)triethoxysilane, 3-(2-aminoethyl)aminoethyl)aminoethyl)aminoethyl)aminoethyl)aminoethyl)aminoethyl)triethoxysilane, 3-(2-aminoethyl)aminoethyl)aminoethyl)aminoethyl)aminoethyl)aminoethyl)aminoethyl)aminoethyl)aminoethyl)triethoxysilane, 3-(2-aminoethyl)aminoethyl)aminoethyl)aminoethyl)aminoethyl Examples of silanes include ethyl(aminopropylmethyldimethoxysilane), 3-(meth)acryloyloxypropyltrimethoxysilane, 3-(meth)acryloyloxypropyltriethoxysilane, 3-(meth)acryloyloxypropylmethyldimethoxysilane, 3-(meth)acryloyloxypropylmethyldiethoxysilane, vinyltrimethoxysilane, vinyltriethoxysilane, 3-isocyanate-propyltrimethoxysilane, 3-mercaptopropylmethyldimethoxysilane, 3-mercaptopropylmethyldiethoxysilane, 3-epoxypropoxypropylmethyldimethoxysilane, and 3-epoxypropoxypropylmethyldiethoxysilane. Among these, compounds having a thiol group as a reactive functional group are preferred from a reactivity perspective.

[0129] The weight-average molecular weight of the moisture-curing resin (B) is not particularly limited, but is preferably between 1,000 and 50,000. If the weight-average molecular weight is above the lower limit, the crosslinking density will not become excessively high during curing, and the flexibility after curing will easily increase. In addition, for example, in the semi-cured state after light curing and before moisture curing, it has a certain hardness, which easily ensures excellent shape retention. Furthermore, by making the weight-average molecular weight below the upper limit, the adhesive composition has moderate fluidity even at room temperature (e.g., 25°C) before curing, and its room temperature coatability becomes good.

[0130] 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.

[0131] The content of moisture-curing resin (B) in the adhesive composition is, for example, 30 to 99.9 parts by mass relative to 100 parts by mass of the total mass of the moisture-curing resin and the free radical polymerizable compound. If the content is above the lower limit mentioned above, it is easy to improve the adhesive strength and also easy to impart appropriate moisture curing properties. On the other hand, if the content is below the upper limit mentioned above, it is easy to contain a certain amount or more of moisture-curing resin (A), and it is easy to achieve a balance between oil resistance and impact resistance.

[0132] From the above perspective and considering that it contains a certain amount or more of the free radical polymerizable compound (C) described later, the moisture-curing resin (B) is preferably 45 parts by mass to 94 parts by mass, more preferably 50 parts by mass to 88 parts by mass, and even more preferably 53 parts by mass to 80 parts by mass.

[0133] The moisture-curing resin is preferably composed of the above-mentioned moisture-curing resins (A) and (B), but other moisture-curing resins besides moisture-curing resins (A) and (B) may also be used as long as the effect of the present invention is not impaired. The moisture-curing resin is a resin that can react with water present in the air or in the adhered material to cure, and may have functional groups such as isocyanate groups and organosilicon groups.

[0134] The content of moisture-curing resins other than moisture-curing resins (A) and (B) is not particularly limited. When the total amount of moisture-curing resin is set to 100 parts by weight, it can be less than 30 parts by weight or less than 10 parts by weight.

[0135] [Free radical polymerizable compound (C)]

[0136] The adhesive composition of the present invention preferably contains a free radical polymerizable compound (C) in addition to the moisture-curing resins (A) and (B) described above. The free radical polymerizable compound (C) is a compound that does not contain isocyanate groups.

[0137] In this invention, by containing a free radical polymerizable compound (C), the adhesive composition can be easily endowed with photocurability, thus producing a photocurable and moisture-curable adhesive composition with excellent photocurability. Therefore, the adhesive composition can impart a certain adhesive force simply by light irradiation, and thus a certain level of adhesive force 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 possesses a certain level of hardness, easily ensuring excellent shape retention. Since the shape retention is excellent, the adhesive composition applied using, for example, a coater, can maintain a certain height after photocuring; therefore, a certain spacing can be maintained between the adhered objects using the cured body formed from the adhesive composition.

[0138] Furthermore, by using a free radical polymerizable compound (C) in addition to moisture-curing resins (A) and (B), the viscosity of the adhesive composition is easily reduced. Therefore, the adhesive composition can easily ensure moderate fluidity at room temperature (e.g., 25°C) before curing, resulting in good coatability.

[0139] It should be noted that the free radical polymerizable compound (C) may be a compound that does not have moisture curing properties, and therefore may not contain the aforementioned organosilicon alkyl or other moisture curing functional groups.

[0140] A free radical polymerizable compound (C) has a free radical polymerizable functional group in its molecule. Compounds with unsaturated double bonds as free radical polymerizable functional groups are suitable, such as (meth)acryloyl, vinyl, styryl, allyl, etc.

[0141] Of the compounds described above, from an adhesive point of view, a (meth)acryloyl group is suitable; that is, the free radical polymerizable compound (C) preferably contains a compound having a (meth)acryloyl group. It should be noted that, hereinafter, compounds having a (meth)acryloyl group are also referred to as "(meth)acrylic acid compounds".

[0142] The radical polymerizable compound (C) preferably contains at least one compound 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 compounds having one radical polymerizable functional group in the molecule, but can also be polyfunctional compounds having two or more radical polymerizable functional groups.

[0143] As free radical polymerizable compounds with aromatic rings, examples include monofunctional (meth)acrylate compounds with aromatic rings. Specifically, examples include benzyl (meth)acrylate, phenylalkyl (meth)acrylate such as 2-phenylethyl (meth)acrylate, and phenoxyalkyl (meth)acrylate such as phenoxyethyl (meth)acrylate. Furthermore, (meth)acrylates with multiple benzene rings, such as fluorene or biphenyl backbones, can also be included; specifically, examples include fluorene-type (meth)acrylates and ethoxylated o-phenylphenol acrylates.

[0144] In addition, examples include phenoxy diethylene glycol (meth) acrylate, phenoxy polyethylene glycol (meth) acrylate, nonylphenoxy diethylene glycol (meth) acrylate, and nonylphenoxy polyethylene glycol (meth) acrylate, as well as other phenoxy polyoxyethylene (meth) acrylates.

[0145] Among them, phenoxyalkyl methacrylate is preferred, and phenoxyethyl methacrylate is more preferred.

[0146] In addition, examples of free radical polymerizable compounds with an imide ring include (meth)acrylate compounds with an imide ring such as N-(meth)acryloyloxyethylhexahydrophthalimide, vinyl compounds with an imide ring such as N-vinyl phthalimide, N-allyl phthalimide, N-(3-buten-1-yne) phthalimide, and N-allyloxyphthalimide.

[0147] The adhesive composition improves oil resistance by containing at least one of a free radical polymerizable compound having an aromatic ring and a free radical polymerizable compound having an imide ring, and thus maintains adhesion better even after contact with oil.

[0148] The radical polymerizable compound (C) may contain one or both of the following: a radical polymerizable compound having an aromatic ring and a radical polymerizable compound having an imide ring. More preferably, the radical polymerizable compound (C) contains at least a radical polymerizable compound having an imide ring.

[0149] The free radical polymerizable compound (C) may consist of at least one selected from free radical polymerizable compounds having an aromatic ring and free radical polymerizable compounds having an imide ring, and may also contain free radical polymerizable compounds other than those (referred to as "other free radical polymerizable compounds").

[0150] The content of compounds selected from the group consisting of free radical polymerizable compounds having aromatic rings and free radical polymerizable compounds having imide rings in the adhesive composition is preferably 20% by mass or more, more preferably 25% by mass or more, further preferably 50% by mass or more, and even more preferably 80% by mass or more, relative to the total amount of free radical polymerizable compounds (C). Furthermore, the above-mentioned content of these compounds is only required to be 100% by mass or less. By increasing the content of these compounds, the oil resistance of the adhesive composition is improved, and high adhesive strength can be maintained even after contact with oil.

[0151] Various aliphatic (meth)acrylate compounds can be cited as other free radical polymerizable compounds. Specifically, aliphatic urethane (meth)acrylates and other (meth)acrylate compounds can be used as other free radical polymerizable compounds.

[0152] It should be noted that, as mentioned above, aliphatic urethane (meth)acrylates do not have residual isocyanate groups. Other free radical polymerizable compounds can be monofunctional or difunctional or multifunctional, but monofunctional is preferred. Furthermore, when using monofunctional aliphatic urethane (meth)acrylates, they can be used in combination with difunctional or multifunctional compounds.

[0153] As described above, aliphatic urethane (meth)acrylates are preferably monofunctional. For example, aliphatic urethane (meth)acrylates obtained by reacting a (meth)acrylate derivative having hydroxyl groups with an isocyanate compound can be used.

[0154] Examples of the above-mentioned (meth)acrylic acid derivatives having hydroxyl groups include, for example, mono(meth)acrylates of diols such as ethylene glycol, 1,2-propanediol, 1,3-propanediol, 1,3-butanediol, 1,4-butanediol, and polyethylene glycol, and mono(meth)acrylates of triols such as trimethylolethane, trimethylolpropane, and glycerol.

[0155] Examples of isocyanate compounds used to obtain aliphatic carbamate (meth)acrylates include alkane monoisocyanates such as butane isocyanate, hexane isocyanate, octane isocyanate, and decane isocyanate (the number of carbon atoms in the alkane is preferably around 3 to 12), and cyclic aliphatic monoisocyanates such as cyclopentane isocyanate, cyclohexane isocyanate, and isophorone monoisocyanate.

[0156] More specifically, the monofunctional aliphatic urethane (meth)acrylate is preferably an urethane (meth)acrylate obtained by reacting the above-mentioned monoisocyanate compound with a diol mono(meth)acrylate. As a preferred specific example, 1,2-ethylene glycol-1-acrylate-2-(N-butylcarbamate) and other 1,2-ethylene glycol-1-acrylate-2-(N-alkylcarbamate) can be cited.

[0157] Furthermore, as a multifunctional aliphatic urethane (meth)acrylate, examples 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. It should be noted that details of the polyol compound and the compound having an isocyanate group and a (meth)acryloyl group are as described in the raw materials section of the moisture-curing polyurethane resin (A1).

[0158] (Meth)acrylate compounds other than aliphatic carbamates (meth)acrylates can be monofunctional or polyfunctional, but are preferably monofunctional.

[0159] Specifically, examples of monofunctional compounds among (meth)acrylate compounds include, for instance, methyl (meth)acrylate, ethyl (meth)acrylate, propyl (meth)acrylate, n-butyl (meth)acrylate, isobutyl (meth)acrylate, tert-butyl (meth)acrylate, n-octyl (meth)acrylate, isooctyl (meth)acrylate, 2-ethylhexyl (meth)acrylate, isononyl (meth)acrylate, isodecanyl (meth)acrylate, lauryl (meth)acrylate, isomyrmethyl (meth)acrylate, stearyl (meth)acrylate, and other alkyl (meth)acrylates; and cyclohexyl (meth)acrylate, 4-tert-butylcyclohexyl (meth)acrylate, 3,3,5-trimethylcyclohexyl (meth)acrylate, isobornyl (meth)acrylate, dicyclopentenyl (meth)acrylate, and other (meth)acrylates with alicyclic structures. Acrylic esters, including 2-hydroxyethyl methacrylate, 2-hydroxypropyl methacrylate, 2-hydroxybutyl methacrylate, 4-hydroxybutyl methacrylate, etc.; hydroxyalkyl methacrylates, including 2-methoxyethyl methacrylate, 2-ethoxyethyl methacrylate, 2-butoxyethyl methacrylate, etc.; alkoxyalkyl methacrylates, including methoxyethylene glycol (meth)acrylate, ethoxyethylene glycol (meth)acrylate, etc.; polyoxyethylene glycol (meth)acrylates, including methoxydiethylene glycol (meth)acrylate, methoxytriethylene glycol (meth)acrylate, methoxypolyethylene glycol (meth)acrylate, ethoxydiethylene glycol (meth)acrylate, ethoxytriethylene glycol (meth)acrylate, ethoxypolyethylene glycol (meth)acrylate, etc.

[0160] In addition, examples of monofunctional (meth)acrylate compounds include tetrahydrofurfuryl methacrylate, alkoxylated tetrahydrofurfuryl methacrylate, cyclic trimethylolpropane acetal (meth)acrylate, 3-ethyl-3-oxetane butyl methyl methacrylate, and other (meth)acrylates with heterocyclic structures such as 2,2,2-trifluoroethyl methacrylate, 2,2,3,3-tetrafluoropropyl methacrylate, 1H,1H,5H-octafluoropentyl methacrylate, dimethylaminoethyl methacrylate, diethylaminoethyl methacrylate, 2-(meth)acryloyloxyethyl succinic acid, 2-(meth)acryloyloxyethyl-2-hydroxypropyl phthalate, glycidyl methacrylate, and 2-(meth)acryloyloxyethyl phosphate.

[0161] Examples of difunctional compounds among (meth)acrylate compounds include, for example, 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, and polyethylene glycol di(meth)acrylate. Dipropylene glycol di(meth)acrylate, tripropylene glycol di(meth)acrylate, polypropylene glycol di(meth)acrylate, dimethyloldicyclopentadienyl di(meth)acrylate, neopentyl glycol di(meth)acrylate, ethylene oxide modified isocyanuric acid di(meth)acrylate, 2-hydroxy-3-(meth)acryloyloxypropyl acrylate, carbonate glycol di(meth)acrylate, polyether glycol di(meth)acrylate, polyester glycol di(meth)acrylate, polycaprolactone glycol di(meth)acrylate, polybutadiene glycol di(meth)acrylate, etc.

[0162] In addition, examples of compounds with three or more functions among (meth)acrylate compounds include, for example, trimethylolpropane tri(meth)acrylate, ethylene oxide addition trimethylolpropane tri(meth)acrylate, propylene oxide addition trimethylolpropane tri(meth)acrylate, caprolactone-modified trimethylolpropane tri(meth)acrylate, pentaerythritol tri(meth)acrylate, ethylene oxide addition isocyanurate tri(meth)acrylate, glycerol tri(meth)acrylate, propylene oxide addition glycerol tri(meth)acrylate, tri(meth)acryloyloxyethyl phosphate, bis(trimethylolpropane)tetra(meth)acrylate, pentaerythritol tetra(meth)acrylate, dipentaerythritol penta(meth)acrylate, and dipentaerythritol hexa(meth)acrylate.

[0163] Other free radical polymerizable compounds besides those described above may also be suitably used. Examples of such free 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. Furthermore, epoxy(meth)acrylates may also be used as (meth)acrylate compounds.

[0164] As a free radical polymerizable compound other than free radical polymerizable compounds having aromatic rings and free radical polymerizable compounds having imide rings, it is preferably at least one selected from the group consisting of aliphatic urethane (meth)acrylates and (meth)acrylate compounds. More preferably, it is at least one selected from the group consisting of aliphatic urethane (meth)acrylates and (meth)acrylates having an alicyclic structure.

[0165] Other free radical polymerizable compounds can be used alone or in combination of two or more.

[0166] The content of the free radical polymeric compound (C) is preferably 5 to 50 parts by mass relative to 100 parts by mass of the total mass of the moisture-curing resin and the free radical polymeric compound. By setting the content of the free radical polymeric compound (C) to the lower limit value or above, it is easy to properly impart photocurability to the adhesive composition, and it is also easy to ensure shape retention after photocuring and before moisture curing. In addition, it is easy to make the adhesive composition have good coatability. On the other hand, by setting it to the upper limit value or below, it is possible to make the amount of moisture-curing resins (A) and (B) a certain amount or more, and to impart appropriate moisture curability to the adhesive composition. From these viewpoints, the content of the free radical polymeric compound (C) is more preferably 10 to 45 parts by mass, and even more preferably 15 to 40 parts by mass.

[0167] (Photopolymerization initiator)

[0168] The adhesive composition of the present invention may further contain a photopolymerization initiator. By containing a photopolymerization initiator in the adhesive composition, photocurability can be suitably imparted to the adhesive composition. When the adhesive composition contains a free radical polymerizable compound (C), a photopolymerization initiator is preferred.

[0169] Examples of photopolymerization initiators include benzophenone compounds, acetophenone compounds, acylphosphine oxide compounds, dicene compounds, oxime ester compounds, benzoin ether compounds, and thioxanone.

[0170] Commercially available photopolymerization initiators mentioned above include, for example, IRGACURE184, IRGACURE369, IRGACURE379, IRGACURE651, IRGACURE784, IRGACURE819, IRGACURE907, IRGACURE2959, IRGACURE OXE01, Lusilin TPO (all manufactured by BASF), benzoin methyl ether, benzoin ethyl ether, and benzoin isopropyl ether (all manufactured by Tokyo Chemical Industry Co., Ltd.).

[0171] Relative to 100 parts by weight of the adhesive composition, the content of the photopolymerization initiator in the adhesive composition is preferably 0.01 parts by weight to 8 parts by weight, more preferably 0.1 parts by weight to 6 parts by weight, and even more preferably 0.4 parts by weight to 4 parts by weight. By keeping the content of the photopolymerization initiator within these ranges, the resulting adhesive composition exhibits excellent photocurability and storage stability. Furthermore, by setting it within the above ranges, the photoradical polymer compound (C) is appropriately cured, facilitating good adhesion.

[0172] (Moisture-curing accelerating catalyst)

[0173] The adhesive composition of the present invention may contain a moisture-curing promoter that promotes the moisture-curing reaction of the moisture-curing resin. By using the moisture-curing promoter, the moisture-curing properties of the adhesive composition are improved, and the adhesive strength is easily enhanced.

[0174] Specifically, examples of moisture-curing promoting catalysts include amine compounds and metal-based catalysts. Examples of amine compounds include compounds with a morpholine skeleton such as di(methylmorpholino)diethyl ether, 4-morpholinopropylmorpholine, and 2,2'-dimorpholinodiethyl ether; amine compounds containing 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.

[0175] Examples of metal-based 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.

[0176] The content of moisture-curing promoting catalyst in the adhesive composition is preferably 0.1 to 10 parts by weight, more preferably 0.2 to 8 parts by weight, and even more preferably 0.3 to 5 parts by weight, relative to 100 parts by weight of the adhesive composition.

[0177] (filler)

[0178] The adhesive composition of the present invention may contain a filler. By containing a filler, the adhesive composition of the present invention exhibits suitable thixotropy, making it easy to maintain good shape after coating. Particulate fillers are suitable as fillers.

[0179] As a filler, an inorganic filler is preferred, such as silica, talc, titanium dioxide, zinc oxide, and calcium carbonate. Among these, silica is preferred from the perspective of excellent ultraviolet transmittance of the adhesive composition. In addition, the filler may also undergo hydrophobic surface treatments such as silylation, alkylation, or epoxyation.

[0180] One type of filler can be used alone, or two or more types can be used in combination.

[0181] The filler content is preferably 0.5 to 30 parts by mass relative to 100 parts by mass of the adhesive composition, more preferably 1 to 25 parts by mass, and even more preferably 2 to 15 parts by mass.

[0182] The adhesive composition of the present invention may contain, in addition to the components described above, coupling agents such as silane coupling agents, titanate coupling agents, and zirconate coupling agents, wax particles, ionic liquids, colorants, foaming particles, expanding particles, reactive diluents, antioxidants, free radical scavengers, and other additives.

[0183] The adhesive composition can be diluted with a solvent as needed. When the adhesive composition is diluted with a solvent, the amounts (parts by mass, % by mass) of the adhesive composition are based on the solids content, i.e., the parts by mass, % by mass after removing the solvent.

[0184] As a method for manufacturing the adhesive composition of the present invention, examples include mixing moisture-curing resins (A) and (B), and, as needed, a free radical polymerizable compound (C), a photopolymerization initiator, a moisture-curing accelerator, a filler, a coupling agent, and other additives using a mixer. Examples of mixers include, for example, homogenizers, homogenizers, universal mixers, planetary mixers (planetary stirring devices), kneaders, and three-roll mills.

[0185] <How to use>

[0186] The adhesive composition of the present invention can be cured and used as a cured body. The adhesive composition of the present invention has at least moisture-curing properties. Therefore, the adhesive composition, for example, can be disposed between two adherends, or a semi-cured adhesive composition, to bond the two adherends by means of an adhesive composition (cured body) that has been cured at least by moisture.

[0187] Furthermore, the adhesive composition of the present invention can be photocurable, and preferably has good photocurability by having a free radical polymerizable compound (C). That is, the adhesive composition is preferably used as a photo-moisture curing type. Therefore, the adhesive composition of the present invention is preferably used as follows: photocured by light irradiation to reach, for example, a B-stage state (semi-cured state), and then further cured by moisture to achieve complete curing.

[0188] Here, in the case where an adhesive composition is disposed between adherends to bond them together, the adhesive composition can be applied to one adherend and then photocured by light irradiation, for example, to a B-stage state. Another adherend is then superimposed on the photocured adhesive composition, and the adherends are temporarily bonded together using a moderate adhesive force. Then, the B-stage adhesive composition is fully cured by using moisture to cure a moisture-curing resin (A), and the adherends superimposed by the adhesive composition are bonded together with sufficient adhesive force.

[0189] The application of the adhesive composition to the substrate can be performed using, for example, a coater, without particular limitation. Furthermore, the light irradiated during light curing is not particularly limited, as long as it is light capable of curing either or both of the moisture-curing resin (A) and the free-radical polymerizable compound (C), but ultraviolet light is preferred. Additionally, when the adhesive composition is fully cured using moisture, it can be left in the atmosphere for a specified time.

[0190] The adhesive composition of the present invention can be used, for example, as an adhesive for electronic components. Furthermore, the adhesive composition of the present invention is preferably used as an adhesive for electronic devices, particularly portable electronic devices. Moreover, electronic components or portable electronic devices using the adhesive composition of the present invention can have a cured form of the adhesive composition.

[0191] The adherends using the adhesive composition are not particularly limited, but are preferably components constituting portable electronic devices, and these components are more preferably electronic components. The material of the adherend can be any material among metal, glass, plastic, etc. Furthermore, the shape of the adherend is not particularly limited, and examples include, for example, film, sheet, plate, panel, tray, rod (rod-shaped body), box, shell, etc.

[0192] Portable electronic devices are not particularly limited, and examples include smartphones and other mobile phones, digital cameras, wearable terminals, portable gaming devices, tablet computers, laptop computers, action cameras, etc., with smartphones and wearable terminals being preferred. The adhesive composition of the present invention has good impact resistance and oil resistance, and is therefore particularly suitable for portable electronic devices.

[0193] Electronic components typically have a substrate; therefore, electronic components using the adhesive composition of the present invention can have a cured form of the adhesive composition and a substrate. Various electronic circuits are typically disposed on the substrate. Similarly, electronic devices such as portable electronic devices using the adhesive composition of the present invention can also have a cured form of the adhesive composition of the present invention and a substrate.

[0194] In electronic components, for example, substrates can be used as adherends to bond substrates to each other using the adhesive composition of the present invention, or substrates can be bonded to other components of electronic devices (e.g., housings) using the adhesive composition of the present invention.

[0195] For example, the adhesive composition of the present invention can be used in the interior of electronic devices, for example, to bond substrates to substrates to obtain an assembly. The assembly obtained as described above has 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.

[0196] Example

[0197] The invention will be described in more detail below with reference to examples, but the invention is not limited to these examples in any way.

[0198] In this embodiment, the adhesive composition was evaluated as described below.

[0199] (Adhesive strength)

[0200] like Figure 1 As shown in (a), the following substrates are prepared: a first substrate 11 with a diameter of 12 mm and a thickness of 5 mm and a circular hole 11A with a diameter of 12 mm in the center; and a second substrate 12 with a diameter of 50 mm and a thickness of 5 mm. Both the first substrate 11 and the second substrate 12 are polycarbonate sheets.

[0201] Using a coater, the adhesive composition 10 is applied in a 20mm × 20mm border 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 at its center. Within one minute after coating, the substrate is irradiated with a UV-LED (wavelength 365nm) at a speed of 1000mJ / cm². 2Ultraviolet light was used to photocur the adhesive composition 10. Then, the second substrate 12 was stacked on the first substrate 11 with the adhesive composition 10 in such a way that the centers of the first substrate 11 and the second substrate 12 were aligned. A 2 kg weight was then placed on the second substrate 12 for 10 seconds, thereby pressing the first substrate 11 and the second substrate 12 together with the adhesive composition 10. The 2 kg weight was then removed, and the sample was placed at 25°C and 50% RH for 24 hours to allow the adhesive composition 10 to undergo moisture curing, resulting in the test sample 13. After moisture curing, the gap material was removed from the test sample 13.

[0202] In the obtained measurement sample 13, with the first substrate 11 on top and the second substrate 12 on the bottom, a rod-shaped member 14 with a circular cross-section and a diameter of 10 mm is inserted into the hole 11A while the first substrate 11 is supported by a stainless steel clamp. Then, as... Figure 1 As shown in (b), the second substrate 12 was pressed vertically downwards at a speed of 10 mm / min using the rod-shaped member 14, and the stress at which the second substrate 12 peeled off from the first substrate 11 was measured as the adhesive force (adhesive force before oil contact). The adhesive force was evaluated according to the following evaluation criteria.

[0203] AA: Adhesion strength is above 4MPa

[0204] A: Adhesion strength is above 3MPa and less than 4MPa

[0205] B: Adhesion strength less than 3MPa

[0206] (Adhesive strength after oil contact)

[0207] The test sample was prepared using the same steps as described above. The sample was completely wrapped in a nonwoven fabric (product name "Kimwaip", manufactured by Nippon Paper Crescent Co., Ltd.) that had absorbed oleic acid, and then sealed in a polyethylene bag. The bag was allowed to cure at 60°C and 90% RH for 2 days. After curing, the sample was washed with ethanol, and the adhesion strength was measured in the same manner as above, which was taken as the adhesion strength after oil contact. The adhesion strength after oil contact was evaluated according to the following evaluation criteria based on the rate of decrease in adhesion strength after oil contact relative to the adhesion strength before oil contact.

[0208] AA: Adhesion strength reduction rate is less than 30%

[0209] A: Adhesion strength reduction rate greater than 30% but less than 50%

[0210] B: Adhesion strength reduction rate greater than 50% but less than 70%

[0211] C: Adhesion strength reduction rate greater than 70%

[0212] (Impact resistance)

[0213] like Figure 2 As shown, the measurement sample 13 is prepared by the same steps as described above, and after the first substrate 11 is arranged on the upper side and the second substrate 12 is on the lower side, the first substrate 11 is supported by a stainless steel clamp.

[0214] Additionally, a clamp 16 (material: stainless steel) is prepared, comprising a flat plate portion 16B (20mm × 20mm, 5mm thick) and a rod-shaped portion 16A (10mm in diameter, cylindrical) connected to the center of the flat plate portion 16B. The rod-shaped portion 16A of the clamp 16 is then placed as follows. Figure 2 Insert it into the hole 11A of the first substrate 11 as shown, so that it stands in the center of the second substrate 12.

[0215] In this state, using a DuPont drop impact tester, a 300g spherical stainless steel weight 15 was repeatedly dropped vertically downwards from a position 200mm above the plate 16B to the center of the plate 16B. The number of times the weight was dropped until the second substrate 12 peeled off due to the impact of the weight 15 was evaluated as the number of durability cycles.

[0216] AA: Durability count is 50 or more.

[0217] A: Durability count is 30 or more but less than 50.

[0218] C: Durability count less than 30 times

[0219] (shape retention)

[0220] The first and second substrates were prepared using the same steps as when preparing the sample for measurement. An adhesive composition was applied to the first substrate and then photocured.

[0221] Then, without using a gap material, the second substrate was stacked on the first substrate in such a way that the centers of the first and second substrates were aligned with each other using an adhesive composition. A 100g weight was then placed on the second substrate for 10 seconds, thereby pressing the first and second substrates together using the adhesive composition. The weight was then removed. The thickness of the adhesive composition after the weight was removed was measured and evaluated according to the following evaluation criteria.

[0222] A: The thickness of the adhesive composition is 0.1 mm or more.

[0223] C: The thickness of the adhesive composition is less than 0.1 mm.

[0224] The moisture-curing resins used in the various embodiments and comparative examples were prepared according to the following synthesis examples.

[0225] <<Moisture-curing resins (1)>>

[0226] [Synthesis example 1]

[0227] 100 parts by mass of polycarbonate diol (the compound represented by formula (1), where 90 mol% of R is 3-methylpentane and 10 mol% is 1,6-hexane, 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 mixture was stirred at 80 °C for 60 minutes under vacuum (below 20 mmHg) to achieve the desired reaction product. Then, under normal pressure, 30 parts by mass of 2-methacryloyloxyethyl isocyanate (manufactured by Showa Denko Co., Ltd., trade name "Kuraray MOI") were added to the resulting product, and the mixture was stirred at 100 °C for 3 hours to achieve the desired reaction product having a polycarbonate (PC) backbone and a methacrylyl group at the end.

[0228] 50 parts by mass of diphenylmethane diisocyanate (manufactured by Higashiso Corporation, trade name "Milionet MT"), a polyisocyanate compound, were added to the obtained reaction product, and the mixture was stirred at 80°C for 3 hours to allow it to react, thereby obtaining a moisture-curing polyurethane resin (1-1) with a polycarbonate (PC) backbone. In the moisture-curing polyurethane resin (1-1), the proportion of moisture-curing polyurethane resin (A1), which has one terminal methacryloyl group and one terminal isocyanate group, is 80% by mass. Additionally, the moisture-curing polyurethane resin (1-1) also contains moisture-curing polyurethane resin (B1), which has two terminal isocyanate groups. The weight-average molecular weight of the obtained moisture-curing polyurethane resin (1-1) is 5000.

[0229] [Synthesis example 2]

[0230] 100 parts by mass of a polyester polyol (a polyester polyol obtained with adipic acid, 1,6-hexanediol and isophthalic acid as the main components, with an aromatic ring concentration of 15% by mass and a weight-average molecular weight of 1000) and 0.01 parts by mass of dibutyltin dilaurate were placed in a 500 mL separable flask. The mixture was stirred at 80°C for 1 hour under vacuum (below 20 mmHg). Then, under normal pressure, 30 parts by mass of 2-methacryloyloxyethyl isocyanate (manufactured by Showa Denko Co., Ltd., trade name "Karrens MOI") were added, and the mixture was stirred at 100°C for 3 hours to allow the reaction to proceed, yielding a reaction product containing a polyester backbone and a methacryloyl group at the end.

[0231] 50 parts by mass of diphenylmethane diisocyanate (manufactured by Higashiso Corporation, trade name "Milionet MT"), a polyisocyanate compound, were added to the obtained reaction product, and the mixture was reacted at 80°C for 3 hours to obtain a moisture-curing polyurethane resin (1-2) with a polyester backbone. In the moisture-curing polyurethane resin (1-2), the proportion of moisture-curing polyurethane resin (A1), which has one terminal methacryloyl group and one terminal isocyanate group, is 80% by mass. Additionally, the moisture-curing polyurethane resin (1-2) also contains a moisture-curing polyurethane resin (B1) with two terminal isocyanate groups. The weight-average molecular weight of the obtained moisture-curing polyurethane resin (1-2) is 3000.

[0232] <<Moisture-curing resins (2)>>

[0233] [Synthesis example 3]

[0234] 100 parts by mass of polycarbonate diol (the compound represented by formula (1), where 90 mol% of R is 3-methylpentane and 10 mol% is 1,6-hexane, 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 mixture was stirred at 100 °C for 30 minutes under vacuum (below 20 mmHg). Then, the pressure was adjusted to atmospheric pressure, and 50 parts by mass of diphenylmethane diisocyanate (manufactured by Higashi Sou Co., Ltd., trade name "Mirionite MT") was added as a polyisocyanate compound. The mixture was stirred at 80 °C for 3 hours to allow it to react, resulting in a moisture-curing polyurethane resin (2-1) having a polycarbonate (PC) backbone and isocyanate groups at both ends. The weight-average molecular weight of the obtained moisture-curing polyurethane resin (2-1) is 6000.

[0235] [Synthesis example 4]

[0236] 100 parts by mass of a polyester polyol (a polyester polyol obtained with adipic acid, 1,6-hexanediol and isophthalic acid as the main components, with an aromatic ring concentration of 15% by mass and a weight-average molecular weight of 1000) and 0.01 parts by mass of dibutyltin dilaurate were placed in a 500 mL separable flask. The mixture was stirred at 100 °C for 30 minutes under vacuum (below 20 mmHg) to achieve a stable pressure. Then, 52.5 parts by mass of diphenylmethane diisocyanate (manufactured by Higashiso, trade name "Milionet MT") was added as a polyisocyanate compound, and the mixture was stirred at 80 °C for 3 hours to allow the reaction to proceed, yielding a moisture-curing polyurethane resin (2-2) containing a polyester backbone and isocyanate groups at both ends. The resulting moisture-curing polyurethane resin (2-2) had a weight-average molecular weight of 1500.

[0237] The components used in each embodiment and comparative example, excluding the moisture-curing polyurethane resin, are described below.

[0238] (Free radical polymeric compounds)

[0239] Acrylates containing an imide ring: Manufactured by Toa Synthetic Co., Ltd., trade name "M-140", N-acryloyloxyethyl hexahydrophthalimide, monofunctional

[0240] Acrylates containing aromatic rings: Kyoei Chemical Co., Ltd., trade name "Light Acrylate PO-A", phenoxyethyl acrylate, monofunctional.

[0241] Aliphatic acrylate: manufactured by Daiser Ornex Co., Ltd., trade name "IBOA-B", isobornyl acrylate, monofunctional

[0242] Filler: Trimethylsilylated silica, manufactured by Aerogel Co., Ltd. of Japan, trade name "R812", primary particle size 7nm

[0243] Photopolymerization initiator: 2-benzyl-2-dimethylamino-1-(4-morpholinylphenyl)-1-butanone, manufactured by BASF, trade name "IRGACURE 369"

[0244] Other additives: free radical scavengers, antioxidants, and moisture-curing catalysts.

[0245] [Examples 1-6, Comparative Examples 1-3]

[0246] According to the mixing ratios recorded in Table 1, each material was stirred at 50°C using a planetary mixer (made by Sinkie Co., Ltd., "Awatori Rentaro"), and then uniformly mixed at 50°C using a ceramic three-roll mill to obtain the adhesive compositions of Examples 1 to 6 and Comparative Examples 1 to 3.

[0247] [Table 1]

[0248]

[0249] As shown in Table 1, in each embodiment, the adhesive composition improves impact resistance and oil resistance by containing moisture-curing resins (A) and (B) with specific structures, maintaining high adhesion even after contact with oil. Furthermore, as shown in Examples 3-5, the adhesive composition also exhibits good shape retention by containing a free radical polymerizable compound (C) in addition to the moisture-curing resins (A) and (B), ensuring a certain spacing between the adhered materials using the cured body formed from the adhesive composition.

[0250] In contrast, in Comparative Examples 1 to 3, although the adhesive composition can ensure a certain or higher adhesive strength due to the presence of moisture-curing resin (B), it cannot improve impact resistance while maintaining good oil resistance because it does not contain moisture-curing resin (A).

Claims

1. An adhesive composition comprising: a moisture-curable resin A having at least either a polycarbonate skeleton or a polyester skeleton, and having an isocyanate group and a methacryl group; and a moisture-curable resin B having an isocyanate group, and not having a methacryl group, the moisture-curable resin A having 1 isocyanate group in one molecule, a content of the moisture-curable resin A is 0.1 mass part to 30 mass part, relative to 100 mass parts of a total amount of the moisture-curable resins and a radical polymerizable compound in the adhesive composition, and, a total amount of the moisture-curable resins and the radical polymerizable compound, in the absence of the radical polymerizable compound, refers to a total content of the moisture-curable resins.

2. The adhesive composition according to claim 1, the moisture-curable resin B having at least either a polycarbonate skeleton or a polyester skeleton.

3. The adhesive composition according to claim 1 or 2, the moisture-curable resin B having a polycarbonate skeleton.

4. The adhesive composition according to claim 1 or 2, the moisture-curable resin B having isocyanate groups at both terminal ends.

5. The adhesive composition according to claim 1 or 2, the moisture-curable resin A having a polycarbonate skeleton.

6. The adhesive composition according to claim 1 or 2, the moisture-curable resin A having an aromatic isocyanate group.

7. The adhesive composition according to claim 1 or 2, further comprising a radical polymerizable compound C not containing an isocyanate group.

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

9. An adhesive for electronic parts, which is formed from the adhesive composition according to any one of claims 1 to 8.

10. An adhesive for portable electronic devices, which is formed from the adhesive composition according to any one of claims 1 to 8.

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

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