Adhesive composition and adhered body

Abstract

To provide an adhesive composition capable of yielding a cured product having sufficient adhesive strength following a hot-humid test.SOLUTION: An adhesive composition includes a (meth)acrylate compound, an epoxy compound, a crosslinking agent, a photoacid generator, and a silane coupling agent. The (meth)acrylate compound includes a monofunctional (meth)acrylate compound. The monofunctional (meth)acrylate compound includes a (meth)acrylate having a fluorine-containing organic group. The crosslinking agent includes a (meth)acrylic resin having a first structural unit derived from a (meth)acrylate having a fluorine-containing organic group, and a second structural unit derived from a (meth)acrylate having a cyclic ether group.SELECTED DRAWING: None

Description

Technical Field

[0001] The present disclosure relates to an adhesive composition and an adherend.

Background Art

[0002] As an adhesive composition, a photocurable composition containing a (meth)acrylate compound, an epoxy compound, and a photoacid generator is known (see, for example, Patent Document 1).

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] Polymers of compounds having fluorine-containing organic groups have attracted attention as materials exhibiting a low refractive index. The present inventors focused on an adhesive composition containing a (meth)acrylate compound, an epoxy compound, and a photoacid generator, and applied a (meth)acrylate having a fluorine-containing organic group as the (meth)acrylate compound to examine the curing reaction. As a result, the present inventors found that the adhesive strength of the cured product of the adhesive composition tends to significantly decrease after a damp heat test (for example, a durability test under the conditions of a temperature of 85°C, a humidity of 85% RH, and a time of 168 hours).

[0005] The main object of the present disclosure is to provide an adhesive composition capable of giving a cured product having sufficient adhesive strength after a damp heat test.

Means for Solving the Problems

[0006] As a result of intensive studies to solve the above problems, the inventors of the present invention have found that by applying a silane coupling agent to a predetermined adhesive composition, a cured product having sufficient adhesive strength can be obtained after a damp heat test, and thus the invention of the present disclosure has been completed.

[0007] The present disclosure includes the following [1] to [5]. [1] An adhesive composition containing a (meth)acrylate compound, an epoxy compound, a crosslinking agent, a photoacid generator, and a silane coupling agent, wherein the (meth)acrylate compound includes a monofunctional (meth)acrylate compound, the monofunctional (meth)acrylate compound includes a (meth)acrylate having a fluorine-containing organic group, the crosslinking agent includes a (meth)acrylic resin having a first structural unit derived from a (meth)acrylate having a fluorine-containing organic group and a second structural unit derived from a (meth)acrylate having a cyclic ether group, Adhesive composition. [2] The adhesive composition according to [1], wherein the (meth)acrylate compound further includes a polyfunctional (meth)acrylate compound. The adhesive composition according to [1]. [3] The adhesive composition according to [1] or [2], wherein the epoxy compound includes an aliphatic epoxy compound. The adhesive composition according to [1] or [2]. [4] The adhesive composition according to [3], wherein the epoxy compound further includes an alicyclic epoxy compound. The adhesive composition according to [3]. [5] An adherend including a first adherend, a second adherend, and an adhesive portion that adheres the first adherend and the second adherend to each other, wherein the adhesive portion contains a cured product of the adhesive composition according to any one of [1] to [4]. Adherend.

Advantages of the Invention

[0008] According to the present disclosure, there is provided an adhesive composition capable of providing a cured product having sufficient adhesive strength after a damp heat test. Some forms of the adhesive composition have sufficient adhesive strength even before the damp heat test, and can provide a cured product having a sufficiently high strength retention rate of the adhesive strength before and after the damp heat test. Further, according to the present disclosure, there is provided an adherend using such an adhesive composition.

Mode for Carrying Out the Invention

[0009] Hereinafter, embodiments of the present disclosure will be described. However, the present disclosure is not limited to the following embodiments.

[0010] In this specification, a numerical range indicated by using "~" indicates a range including the numerical values described before and after "~" as the minimum value and the maximum value, respectively. In the numerical ranges described stepwise in this specification, the upper limit value or the lower limit value of a certain stepwise numerical range may be replaced with the upper limit value or the lower limit value of another stepwise numerical range. Further, in the numerical ranges described in this specification, the upper limit value or the lower limit value of the numerical range may be replaced with the value shown in the examples. Further, the individually described upper limit value and lower limit value can be arbitrarily combined. In the notation of the numerical range "A~B", the numerical values A and B at both ends are included in the numerical range as the lower limit value and the upper limit value, respectively. In this specification, for example, the description "10 or more" means "10" and "a numerical value exceeding 10", and the same applies when the numerical values are different. Further, for example, the description "10 or less" means "10" and "a numerical value less than 10", and the same applies when the numerical values are different.

[0011] In this specification, the (meth)acrylate compound means a compound having one or more (meth)acryloyl groups. The monofunctional (meth)acrylate compound means a compound having one (meth)acryloyl group, and the polyfunctional (meth)acrylate compound means a compound having two or more (meth)acryloyl groups. The (meth)acrylic resin means a (co)polymer having at least a structural unit derived from the (meth)acrylate compound. The (meth)acryloyl group means an acryloyl group or a corresponding methacryloyl group. The same applies to other similar expressions such as (meth)acrylate. Also, "A or B" means that either A or B may be included, or both may be included.

[0012] In this specification, the cyclic ether group means a group obtained by removing one hydrogen atom directly bonded to a carbon atom from a compound having a cyclic ether such as oxirane or oxetane. The cyclic ether group may be a group obtained by removing one hydrogen atom directly bonded to a carbon atom from a compound having a three-membered or four-membered cyclic ether. Examples of such a cyclic ether group include an epoxy group (oxiranyl group), an oxetanyl group, and an alicyclic epoxy group such as an epoxycyclohexyl group (an epoxy group formed together with two carbon atoms constituting the alicyclic ring).

[0013] Unless otherwise specified, the materials exemplified below may be used alone or in combination of two or more. The amount of use or content of each component means the total amount of the plurality of substances present in the composition when there are a plurality of substances corresponding to each component in the composition, unless otherwise specified.

[0014] [Adhesive Composition] The adhesive composition of one embodiment contains a (meth)acrylate compound (hereinafter sometimes referred to as “component (A)”), an epoxy compound (hereinafter sometimes referred to as “component (B)”), a crosslinking agent (hereinafter sometimes referred to as “component (C)”), a photoacid generator (hereinafter sometimes referred to as “component (D)”), and a silane coupling agent (hereinafter sometimes referred to as “component (E)”). The adhesive composition may further contain, for example, a photo radical generator (hereinafter sometimes referred to as “component (F)”).

[0015] (A) component: (meth)acrylate compound (A) component includes a monofunctional (meth)acrylate compound (hereinafter sometimes referred to as “component (Aa)”), and may further include a polyfunctional (meth)acrylate compound (hereinafter sometimes referred to as “component (Ab)”).

[0016] (Aa) component includes a (meth)acrylate having a fluorine-containing organic group (hereinafter sometimes referred to as “component (Aa1)”). (Aa) component may further include a (meth)acrylate having a hydroxy group (hereinafter sometimes referred to as “component (Aa2)”). (Aa) component may further include a (meth)acrylate having an alkoxy group (hereinafter sometimes referred to as “component (Aa3)”).

[0017] (Aa) component contains (Aa1) component, so that the cured product of the adhesive composition can have a lower refractive index. The (A1) component may be, for example, a (meth)acrylate having a fluoroalkyl group. Examples of the (meth)acrylate having a fluoroalkyl group include trifluoromethyl (meth)acrylate, 2,2,2-trifluoroethyl (meth)acrylate, 1,1,1,3,3,3-hexafluoro-2-propyl (meth)acrylate, perfluoroethyl methyl (meth)acrylate, perfluoropropyl methyl (meth)acrylate, perfluorobutyl methyl (meth)acrylate, perfluoropentyl methyl (meth)acrylate, perfluorohexyl methyl (meth)acrylate, perfluoroheptyl methyl (meth)acrylate, perfluorooctyl methyl (meth)acrylate, perfluorononyl methyl (meth)acrylate, perfluorodecyl methyl (meth)acrylate, perfluoroundecyl methyl (meth)acrylate, perfluorododecyl methyl (meth)acrylate, perfluorotridecyl methyl (meth)acrylate, perfluorotetradecyl methyl (meth)acrylate, 2-(trifluoromethyl)ethyl (meth)acrylate, 2-(perfluoroethyl)ethyl (meth)acrylate, 2-(perfluoropropyl)ethyl (meth)acrylate, 2-(perfluorobutyl)ethyl (meth)acrylate, 2-(perfluoropentyl)ethyl (meth)acrylate, 2-(perfluorohexyl)ethyl (meth)acrylate, 2-(perfluoroheptyl)ethyl (meth)acrylate, 2-(perfluorooctyl)ethyl (meth)acrylate, 2-(perfluorononyl)ethyl (meth)acrylate, 2-(perfluorotridecyl)ethyl (meth)acrylate, 2-(perfluorotetradecyl)ethyl (meth)acrylate, etc.

[0018] (Aa1) In the (meth)acrylate having a fluoroalkyl group as a component, the number of carbon atoms of the fluoroalkyl group may be, for example, 1 to 20, may be 2 or more, 3 or more, 4 or more, or 6 or more, from the viewpoint of reducing the refractive index of the cured product, and may be 18 or less, 16 or less, 14 or less, or 12 or less.

[0019] (Aa1) In the (meth)acrylate having a fluoroalkyl group as a component, the ratio of fluorine atoms of the fluoroalkyl group is calculated based on the total amount of hydrogen atoms and fluorine atoms directly bonded to the carbon atoms constituting the fluoroalkyl group. For example, in the trifluoromethyl group of trifluoromethyl (meth)acrylate, since there are 3 fluorine atoms and 0 hydrogen atoms, the ratio of fluorine atoms is 100%. For example, in the 2,2,2-trifluoroethyl group of 2,2,2-trifluoroethyl (meth)acrylate, since there are 3 fluorine atoms and 2 hydrogen atoms, the ratio of fluorine atoms is 60%. From the viewpoint of reducing the refractive index of the cured product, the ratio of the fluorine atoms may be, for example, 100% or less, 90% or less, or 80% or less, and may be 30% or more, 40% or more, or 50% or more.

[0020] (Aa1) From the viewpoint of reducing the refractive index of the cured product, the content of the (Aa1) component may be 5% by mass or more, 15% by mass or more, 25% by mass or more, 30% by mass or more, 35% by mass or more, 40% by mass or more, or 45% by mass or more, based on the total amount of the (Aa) component, and may be 70% by mass or less, 65% by mass or less, or 60% by mass or less.

[0021] (Aa) By including the (Aa2) component, the curability and adhesiveness of the adhesive composition can be further improved. The (A2) component may be, for example, a (meth)acrylate having a hydroxyalkyl group. Examples of the (meth)acrylate having a hydroxyalkyl group include 2-hydroxyethyl (meth)acrylate, 2-hydroxypropyl (meth)acrylate, 3-hydroxypropyl (meth)acrylate, 4-hydroxybutyl (meth)acrylate, and the like.

[0022] From the viewpoint of the curability and adhesiveness of the adhesive composition, the content of the (Aa2) component may be 0.1% by mass or more, 1% by mass or more, or 2% by mass or more, based on the total amount of the (Aa) component, and may be 15% by mass or less, 12% by mass or less, 10% by mass or less, or 8% by mass or less.

[0023] By the (Aa) component containing the (Aa3) component, the solubility of the (C) component described later can be improved, and furthermore, the transmittance of the cured product of the adhesive composition can be further improved. The (Aa3) component may be, for example, a (meth)acrylate having an alkoxyalkyl group. Examples of the (A3) component include 2-methoxyethyl acrylate, 2-ethoxyethyl (meth)acrylate, and the like.

[0024] From the viewpoint of the solubility of the (C) component, the content of the (Aa3) component may be 5% by mass or more, 10% by mass or more, 20% by mass or more, 30% by mass or more, or 35% by mass or more, based on the total amount of the (Aa) component, and may be 65% by mass or less, 60% by mass or less, 55% by mass or less, or 50% by mass or less.

[0025] The (Aa) component may contain other (meth)acrylates (hereinafter sometimes referred to as the "(Aa4) component") as long as the effects of the present disclosure are not inhibited. Examples of the (Aa4) component include monofunctional (meth)acrylates having one (meth)acryloyl group other than the (Aa1) component, the (Aa2) component, and the (Aa3) component.

[0026] Examples of the component (Aa4) include alkyl (meth)acrylates having an alkyl group such as methyl (meth)acrylate, ethyl (meth)acrylate, n-butyl (meth)acrylate, isobutyl (meth)acrylate, tert-butyl (meth)acrylate, n-hexyl (meth)acrylate, n-octyl (meth)acrylate, isooctyl (meth)acrylate, 2-ethylhexyl (meth)acrylate, isodecyl (meth)acrylate, dodecyl (meth)acrylate; alkenyl (meth)acrylates having an alkenyl group such as 3-butenyl (meth)acrylate; (meth)acrylates having an aromatic group such as benzyl (meth)acrylate and phenoxyethyl (meth)acrylate; (meth)acrylates having an alicyclic group such as cyclohexyl (meth)acrylate, isobornyl (meth)acrylate, and dicyclopentanyl (meth)acrylate; (meth)acrylates having a heterocyclic group such as 4-(meth)acryloylmorpholine; alkoxypolyalkylene glycol (meth)acrylates such as methoxyethylene glycol (meth)acrylate, methoxytetraethylene glycol (meth)acrylate, methoxyhexaethylene glycol (meth)acrylate, and methoxyoctaethylene glycol (meth)acrylate; polyalkylene glycol mono(meth)acrylates such as tetraethylene glycol mono(meth)acrylate, hexaethylene glycol mono(meth)acrylate, and octapropylene glycol mono(meth)acrylate; and (meth)acrylates having a siloxane skeleton.

[0027] The content of the component (Aa4) may be 0 to 45% by mass, 0 to 40% by mass, 0 to 30% by mass, 0 to 25% by mass, 0 to 10% by mass, or 0 to 5% by mass based on the total amount of the component (Aa).

[0028] The content of the component (Aa) may be 70% by mass or more, 75% by mass or more, 80% by mass or more, or 85% by mass or more, and may be 100% by mass or less, 99% by mass or less, 97% by mass or less, or 95% by mass or less based on the total amount of the component (A).

[0029] (A) component may contain (Ab) component. By containing (Ab) component in (A) component, a cured product excellent in terms of initial adhesion strength and further excellent in terms of adhesion strength tends to be easily obtained.

[0030] Examples of (Ab) component include difunctional (meth)acrylates such as ethylene glycol di(meth)acrylate, diethylene glycol di(meth)acrylate, polyethylene glycol di(meth)acrylate, dipropylene glycol di(meth)acrylate, tripropylene glycol di(meth)acrylate, polypropylene glycol di(meth)acrylate, 1,9-nonanediol di(meth)acrylate, polyethylene glycol di(meth)acrylate, tetraethylene glycol di(meth)acrylate, 1,6-hexanediol di(meth)acrylate, neopentyl glycol di(meth)acrylate, 1,3-bis((meth)acryloyloxy)-2-propanol, dioxane glycol di(meth)acrylate, EO-modified di(meth)acrylate of isocyanuric acid, dimethylol tricyclodecane di(meth)acrylate, 1,3-adamantanediol di(meth)acrylate; trifunctional (meth)acrylates such as trimethylolpropane tri(meth)acrylate, EO-modified trimethylolpropane tri(meth)acrylate, PO-modified trimethylolpropane tri(meth)acrylate, PO-modified glycerin tri(meth)acrylate, EO-modified tri(meth)acrylate of isocyanuric acid; tetrafunctional (meth)acrylates such as pentaerythritol tetra(meth)acrylate, sorbitol tetra(meth)acrylate, ditrimethylolpropane tetra(meth)acrylate, dipentaerythritol tetra(meth)acrylate propionate; pentafunctional (meth)acrylates such as sorbitol penta(meth)acrylate; hexafunctional (meth)acrylates such as dipentaerythritol hexa(meth)acrylate, sorbitol hexa(meth)acrylate, alkylene oxide-modified hexa(meth)acrylate of phosphazene, caprolactone-modified dipentaerythritol hexa(meth)acrylate, etc.

[0031] (The (Ab) component may contain a trifunctional or higher (meth)acrylate compound because the effects of the present disclosure can be more easily obtained. The trifunctional or higher (meth)acrylate compound may be a decafunctional or lower (meth)acrylate compound, and may also be an octafunctional or lower (meth)acrylate compound or a hexafunctional or lower (meth)acrylate compound.)

[0032] (The (Ab) component may be an acrylate compound having an acryloyl group and not having a methacryloyl group, or may be a methacrylate compound having a methacryloyl group and not having an acryloyl group. Since the effects of the present disclosure can be more easily obtained, the (Ab) component may be an acrylate compound having an acryloyl group and not having a methacryloyl group.)

[0033] (The content of the (Ab) component may be 0% by mass or more, 1% by mass or more, 3% by mass or more, or 5% by mass or more, based on the total amount of the (A) component, and may be 30% by mass or less, 25% by mass or less, 20% by mass or less, or 85% by mass or less.)

[0034] (The content of the (A) component (total amount of the (Aa) component and the (Ab) component) may be 20% by mass or more, 25% by mass or more, or 30% by mass or more, based on the total amount of the adhesive composition, and may be 60% by mass or less, 55% by mass or less, 50% by mass or less, or 45% by mass or less.)

[0035] (B) component: epoxy compound (The (B) component is a compound having one or more epoxy groups. The (B) component may be a compound having two or more epoxy groups. The (B) component may contain an aliphatic epoxy compound (hereinafter sometimes referred to as the "(B1) component"). The (B) component may contain an alicyclic epoxy compound (hereinafter sometimes referred to as the "(B2) component"). The (B) component may contain both the (B1) component and the (B2) component.)

[0036] (Component (B) containing component (B1) tends to improve the compatibility and crosslinkability of the adhesive composition. Component (B1) may be an aliphatic diglycidyl ether having at least one aliphatic group (linking group) selected from the group consisting of an alkylene group, an oxyalkylene group, and a cycloalkylene group. Further, component (B1) may be an epoxy compound having no aromatic ring.)

[0037] Examples of the aliphatic diglycidyl ether include diglycidyl ethers having an alkylene group such as ethylene glycol diglycidyl ether, propylene glycol diglycidyl ether, neopentyl glycol diglycidyl ether, 1,4-butanediol diglycidyl ether, 1,6-hexanediol diglycidyl ether; diglycidyl ethers having an oxyalkylene group such as diethylene glycol diglycidyl ether, tripropylene glycol diglycidyl ether, polyethylene glycol diglycidyl ether; diglycidyl ethers having a cycloalkylene group such as hydrogenated bisphenol A diglycidyl ether, 1,4-cyclohexanedimethanol diglycidyl ether, diglycidyl-1,2-cyclohexanedicarboxylate, and the like.)

[0038] (The content of component (B1) may be 10% by mass or more, 20% by mass or more, 30% by mass or more, 40% by mass or more, 50% by mass or more, or 60% by mass or more, based on the total amount of component (B), and may be 100% by mass or less, 90% by mass or less, or 85% by mass or less.)

[0039] (Component (B2) is a compound having an epoxy group (for example, an epoxycyclohexyl group) formed together with two carbon atoms constituting an alicyclic ring. When component (B) contains component (B2), the heat resistance and crosslinkability of the adhesive composition tend to be improved. Examples of commercially available products of component (B2) include Celoxide 8010, Celoxide 2021P, Celoxide 2081 (trade names, all manufactured by Daicel Corporation), and the like. Further, component (B2) may be an epoxy compound having no aromatic ring.)

[0040] The content of component (B2) may be 0% by mass or more, 10% by mass or more, or 15% by mass or more, and may be 90% by mass or less, 80% by mass or less, 70% by mass or less, 60% by mass or less, 50% by mass or less, or 40% by mass or less, based on the total amount of component (B).

[0041] In addition to components (B1) and (B2), component (B) may contain other epoxy compounds (hereinafter sometimes referred to as “component (B3)”) as long as the effects of the present disclosure are not inhibited. Examples of the other epoxy compounds include epoxy compounds having an aromatic ring.

[0042] Examples of component (B3) include diglycidyl phthalate, bisphenol A type epoxy resin, bisphenol F type epoxy resin, bisphenol AD type epoxy resin, bisphenol S type epoxy resin, phenol novolak type epoxy resin, cresol novolak type epoxy resin, biphenyl type epoxy resin, and biphenyl aralkyl type epoxy resin.

[0043] The content of component (B3) may be 0 to 40% by mass, 0 to 30% by mass, 0 to 20% by mass, or 0 to 10% by mass, based on the total amount of component (B).

[0044] The content of component (B) (the total amount of components (B1), (B2), and (B3)) may be 5% by mass or more, 10% by mass or more, 15% by mass or more, or 20% by mass or more, and may be 50% by mass or less, 45% by mass or less, or 40% by mass or less, based on the total amount of the adhesive composition.

[0045] Component (C): Crosslinking agent Component (C) contains a (meth)acrylic resin having a first structural unit derived from a (meth)acrylate having a fluorine-containing organic group and a second structural unit derived from a (meth)acrylate having a cyclic ether group. The crosslinking agent may be composed of the (meth)acrylic resin.

[0046] The (meth)acrylate having a fluoroorganic group that provides a first structural unit may be, for example, a (meth)acrylate having a fluoroalkyl group. Examples of the (meth)acrylate having a fluoroalkyl group include those exemplified in the component (A1).

[0047] In the (meth)acrylate having a fluoroalkyl group, the number of carbon atoms of the fluoroalkyl group may be, for example, 1 to 10, may be 2 or more, and may be 8 or less, 6 or less, 4 or less, or 3 or less from the viewpoint of compatibility with the component (A) or its polymer.

[0048] In the (meth)acrylate having a fluoroalkyl group, the proportion of fluorine atoms in the fluoroalkyl group may be, for example, 100% or less, 80% or less, or 70% or less, and may be 30% or more, 40% or more, or 50% or more from the viewpoint of compatibility with the component (A) or its polymer.

[0049] The content of the first structural unit may be 10 to 90 mol%, 20 to 90 mol%, 30 to 90 mol%, or 40 to 90 mol% based on all the structural units of the (meth)acrylic resin from the viewpoint of compatibility with the component (A) or its polymer.

[0050] The (meth)acrylate having a cyclic ether group that provides a second structural unit may be at least one selected from the group consisting of, for example, (meth)acrylates having an epoxy group, (meth)acrylates having an alicyclic epoxy group, and (meth)acrylates having an oxetanyl group. Examples of the (meth)acrylate having an epoxy group include glycidyl (meth)acrylate and the like. Examples of the (meth)acrylate having an alicyclic epoxy group include 3,4-epoxycyclohexylmethyl (meth)acrylate and the like. Examples of the (meth)acrylate having an oxetanyl group include (3-ethyloxetan-3-yl)methyl (meth)acrylate and the like.

[0051] In the (meth)acrylic resin, the content of the second structural unit may be 10 to 90 mol%, 10 to 80 mol%, 10 to 70 mol%, or 10 to 60 mol% based on all the structural units of the (meth)acrylic resin from the viewpoint of crosslinkability with the component (B).

[0052] The (meth)acrylic resin may have other structural units other than the first structural unit and the second structural unit as long as the effects of the invention of the present disclosure are not inhibited. Examples of the compound that provides other structural units include monofunctional (meth)acrylates having one (meth)acryloyl group such as alkyl (meth)acrylates having an alkyl group, (meth)acrylates having an aromatic group, (meth)acrylates having an alicyclic group, (meth)acrylates having a nitrogen-containing oxygen heterocyclic group, alkoxypolyalkylene glycol (meth)acrylates, polyalkylene glycol mono(meth)acrylates, (meth)acrylates having a siloxane skeleton, etc.; polyfunctional (meth)acrylates having two or more (meth)acryloyl groups such as aliphatic poly(meth)acrylates and aromatic poly(meth)acrylates; compounds having a radically polymerizable group other than the (meth)acryloyl group such as styrene, 4-methylstyrene, vinylpyridine, vinylpyrrolidone, vinyl acetate, cyclohexyl maleimide, phenyl maleimide, etc.

[0053] The content of the other structural units may be 0 to 40 mol%, 0 to 30 mol%, 0 to 20 mol%, or 0 to 10 mol% based on all the structural units of the (meth)acrylic resin.

[0054] The weight average molecular weight (Mw) of the (meth)acrylic resin may be, for example, 1000 to 200000, may be 3000 or more, 5000 or more, or 10000 or more, and may be 150000 or less, 100000 or less, 60000 or less, or 50000 or less. The weight average molecular weight (Mw) is a polystyrene conversion value using a calibration curve with standard polystyrene by gel permeation chromatography (GPC). The weight average molecular weight (Mw) can be measured, for example, by the method described in the examples.

[0055] (Meth)acrylic resins can be obtained, for example, by radical polymerization using the solution polymerization method. More specifically, it can be obtained by polymerizing monomers including (meth)acrylate having a cyclic ether group and (meth)acrylate having a fluorine-containing organic group in a solvent.

[0056] As the solvent, an organic solvent generally used in the field of radical polymerization can be appropriately selected and used. Since the solvent can be directly used in the polymerization reaction and blended with the crosslinking agent ((meth)acrylic resin) without performing an isolation operation (without removing and replacing the solvent) on the curing reaction of a curable resin such as a compound having a cyclic ether group (epoxy resin), it may be a solvent having a cyclic ether group (epoxy group or oxetanyl group) and not having a radical polymerizable group. Examples of the solvent include those generally used in the field of diluents for epoxy resins. Further, examples of the solvent include epoxy resins that are liquid at 25°C. From the viewpoint of being able to be used as the component (B1), the solvent may be, for example, an aliphatic diglycidyl ether. Examples of the aliphatic diglycidyl ether include those exemplified as the component (B1).

[0057] In the present specification, the radical polymerizable group means a group having a carbon-carbon double bond. Examples of the radical polymerizable group include (meth)acryloyl group, vinyl group, allyl group, styryl group, alkenyl group, alkenylene group, maleimide group, etc.

[0058] The amount of the solvent used can be appropriately set according to the type of the monomer, reaction conditions, the proportion of the solid content of the (meth)acrylic resin solution, etc.

[0059] When polymerizing the monomer, a thermal radical generator, an additive, etc. may be added as necessary.

[0060] Examples of the thermal radical generator include organic peroxides such as cumene hydroperoxide, diisopropylbenzene hydroperoxide, di-t-butyl peroxide, lauroyl peroxide, benzoyl peroxide, t-butyl peroxyisopropyl carbonate, t-amyl peroxy-2-ethylhexanoate, and t-butyl peroxy-2-ethylhexanoate; and azo compounds such as 2,2'-azobis(isobutyronitrile), 1,1'-azobis(cyclohexanecarbonitrile), 2,2'-azobis(2,4-dimethylvaleronitrile), and dimethyl-2,2'-azobis(2-methylpropionate).

[0061] The addition amount of the thermal radical generator may be appropriately set according to the type of monomer, reaction conditions, etc., and is not particularly limited. However, based on the total amount of the monomer, it may be 100 to 200,000 mass ppm, 100 to 100,000 mass ppm, 1000 to 100,000 mass ppm, 1000 to 50,000 mass ppm, 3000 to 30,000 mass ppm, or 10,000 to 80,000 mass ppm.

[0062] Examples of the additive include a chain transfer agent, an antioxidant, a light stabilizer, a weather stabilizer, an ultraviolet absorber, a radical scavenger, etc. The addition amount of the additive is not particularly limited, but based on the total amount of the monomer, it may be 0.001 to 2 mass% or 0.005 to 1 mass%.

[0063] The polymerization temperature may be 40 to 120 °C, 50 to 100 °C, or 60 to 90 °C. Also, the polymerization time may be 0.1 to 24 hours, 0.5 to 20 hours, or 1 to 12 hours.

[0064] The content of the component (C) may be 5 mass% or more, 8 mass% or more, 10 mass% or more, 12 mass% or more, or 15 mass% or more, and may be 40 mass% or less, 35 mass% or less, or 30 mass% or less, based on the total amount of the adhesive composition.

[0065] (D) Component: Photoacid generator (D) component may be a component that generates an acid to initiate polymerization upon irradiation with light having wavelengths in the range of 150 to 750 nm or light having wavelengths in the range of 254 to 405 nm. (D) component may be a component that generates radicals and an acid upon irradiation with ultraviolet light.

[0066] Examples of (D) component include onium salts such as sulfonium salts, phosphonium salts, ammonium salts, diazonium salts, iodonium salts, and anilinium salts. Examples of the anion of the onium salt include, for example, BF4 - , BR4 - (R represents a phenyl group substituted with two or more fluorine atoms or two or more trifluoromethyl groups.), PF6 - , SbF6 - , AsF6 - , SO4R - (R represents an alkyl group), etc.

[0067] Examples of commercially available products of (D) component include, for example, CPI-100P, CPI-110P, CPI-101A, CPI-200K, CPI-210S (all manufactured by San-Apro Ltd.), UVI-6990, UVI-6992, UVI-6976 (all manufactured by Dow Chemical Japan Ltd.), SP-150, SP-152, SP-170, SP-172, SP-300 (all manufactured by ADEKA Corporation), etc.

[0068] The content of (D) component may be, for example, 0.1 part by mass or more, 0.5 part by mass or more, or 1 part by mass or more, and may be 15 parts by mass, 10 parts by mass or less, or 8 parts by mass or less, based on 100 parts by mass of the total amount of (B) component and (C) component.

[0069] (E) component: silane coupling agent When the adhesive composition contains the component (E), it becomes possible to provide a cured product having sufficient adhesive strength after the damp heat test. The reason why such an effect is exhibited is not necessarily clear, but the inventors of the present invention believe that the interfacial adhesion is strengthened by the silane coupling agent and it is possible to prevent the intrusion of water during wetting. The component (E) may be, for example, a compound having a hydrolyzable silyl group and a functional group capable of reacting with either a (meth)acrylate compound or an epoxy compound. The hydrolyzable silyl group is, for example, a group having a silicon atom and 1 to 3 alkoxy groups bonded to the silicon atom. The number of carbon atoms of the alkoxy group bonded to the silicon atom may be, for example, 1 to 4. Examples of the functional group include amino groups such as primary amino group and secondary amino group, epoxy group, mercapto group, (meth)acryloyl group, isocyanate group, and the like. Since the functional group is excellent in terms of the strength retention rate (strength maintenance rate) of the adhesive strength before and after the damp heat test, it may be an isocyanate group. In the present specification, a compound having a hydrolyzable silyl group and a (meth)acryloyl group, and a compound having a hydrolyzable silyl group and an epoxy group are classified as silane coupling agents.

[0070] Examples of commercially available products of the component (E) include KBM-303, KBM-402, KBM-403, KBE-402, KBE-403, KBM-4803, KBM-502, KBM-503, KBE-502, KBE-503, KBM-5103, KBM-5803, KBM-602, KBM-603, KBM-903, KBE-903, KBE-9103P, KBM-573, KBM-575, KBM-802, KBM-803, KBE-9007N (trade names, manufactured by Shin-Etsu Chemical Co., Ltd.).

[0071] The content of the component (E) may be 0.1% by mass or more, 0.2% by mass or more, or 0.3% by mass or more, and may be 10% by mass or less, 8% by mass or less, 5% by mass or less, 3% by mass or less, or 2% by mass or less based on the total amount of the adhesive composition.

[0072] (F) Component: Photo radical generator (F) component may be a component that generates radicals upon irradiation with light having wavelengths in the range of 150 to 750 nm or light having wavelengths in the range of 254 to 405 nm. (F) component may be a component that generates radicals upon irradiation with ultraviolet light. (F) component may mainly be a component that acts on (A) component.

[0073] (F) component decomposes by light to generate free radicals. That is, (F) component is a compound that generates radicals by the application of external light energy. (F) component may be a compound having a structure such as an oxime ester structure, a bisimidazole structure, an acridine structure, an α - aminoalkylphenone structure, an aminobenzophenone structure, an N - phenylglycine structure, an acylphosphine oxide structure, a benzyldimethylketal structure, an α - hydroxyalkylphenone structure, etc. (F) component may be, for example, a compound having a structure selected from the group consisting of an oxime ester structure, an α - aminoalkylphenone structure, and an acylphosphine oxide structure, and may also be a compound having an acylphosphine oxide structure.

[0074] Specific examples of the compound having an oxime ester structure include 1 - phenyl - 1,2 - butanedione - 2 - (o - methoxycarbonyl)oxime, 1 - phenyl - 1,2 - propanedione - 2 - (o - methoxycarbonyl)oxime, 1 - phenyl - 1,2 - propanedione - 2 - (o - ethoxycarbonyl)oxime, 1 - phenyl - 1,2 - propanedione - 2 - o - benzoyloxime, 1,3 - diphenylpropanetrione - 2 - (o - ethoxycarbonyl)oxime, 1 - phenyl - 3 - ethoxypropanetrione - 2 - (o - benzoyl)oxime, etc.

[0075] Specific examples of the compound having an α - aminoalkylphenone structure include 2 - methyl - 1 - [4 - (methylthio)phenyl] - 2 - morpholinopropan - 1 - one, 2 - benzyl - 2 - dimethylamino - 1 - (morpholinophenyl) - butan - 1 - one, etc.

[0076] Specific examples of the compound having an acylphosphine oxide structure include bis(2,6-dimethoxybenzoyl)-2,4,4-trimethyl-pentylphosphine oxide, bis(2,4,6,-trimethylbenzoyl)phenylphosphine oxide, diphenyl(2,4,6-trimethylbenzoyl)phosphine oxide, and the like.

[0077] The content of the (F) component may be, for example, 0.1 to 15 parts by mass, 0.5 to 10 parts by mass, or 1 to 8 parts by mass with respect to 100 parts by mass of the total amount of the (A) component.

[0078] The adhesive composition may contain other components. Examples of the other components include antioxidants, photosensitizers, and the like.

[0079] The content of the antioxidant may be 0.1 to 10% by mass based on the total amount of the adhesive composition.

[0080] Examples of the photosensitizer include benzoflavin, anthracene, pyrene, thioxanthone, benzophenone, anthraquinone, camphorquinone, coumarin dyes, oxazole compounds, and the like.

[0081] The content of the photosensitizer may be 0.01 to 10% by mass based on the total amount of the adhesive composition, or may be 0.01 to 1% by mass.

[0082] The adhesive composition can be prepared by mixing (or kneading) the (A) component, (B) component, (C) component, (D) component, (E) component, (F) component, and other components. The mixing can be appropriately performed by combining a normal stirrer and a disperser such as a planetary mixer. Further, in the mixing, a defoaming treatment may be appropriately performed by vacuum degassing or the like.

[0083] The adhesive composition can form an adhesive part (adhesive layer) excellent in adhesiveness to various adherends. The adhesive part can be obtained by disposing the adhesive composition at a predetermined position and irradiating the disposed adhesive composition with light. The adhesive part contains a cured product of the adhesive composition. The light irradiation may be performed directly on the adhesive composition or through a transparent resin, glass, or the like.

[0084] The light for light irradiation may be light including wavelengths in the range of 150 to 750 nm or light including wavelengths in the range of 254 to 405 nm, and may be ultraviolet light.

[0085] Examples of the light source for light irradiation include a low-pressure mercury lamp, a medium-pressure mercury lamp, a high-pressure mercury lamp, an ultra-high-pressure mercury lamp, a xenon lamp, a metal halide lamp, an LED light source, etc. The integrated light amount of light irradiation can be set as appropriate, for example, it may be 100 to 5000 mJ / cm 2 and may be.

[0086] The atmosphere for light irradiation is not particularly limited, but may be, for example, an air atmosphere or an inert gas atmosphere such as nitrogen or argon.

[0087] The infrared transmittance of the cured product of the adhesive composition may be 70% or more, and may be 75% or more, 80% or more, 85% or more, or 90% or more. The infrared transmittance can be determined by measuring the transmittance at a wavelength of 1310 nm using a spectrophotometer. The measurement sample can be prepared by the following procedure. First, a spacer film with a thickness of 500 μm is disposed on a release film so that the dimensions are 50 mm in width × 50 mm and 500 μm in thickness, and the adhesive composition is applied on the release film. Next, using an LED lamp (manufactured by Ushio Denki Co., Ltd., wavelength: 365 nm), the adhesive composition is irradiated with light under the conditions of 30 mW / cm 2 , 30 seconds. After 600 seconds have elapsed since the end of the light irradiation, it is peeled off from the release film to obtain a measurement sample. Also, for the baseline, glass used as a base material can be adopted.

[0088] [Adhesive body] An adhesive body according to one embodiment includes a first adherend, a second adherend, and an adhesive portion that adheres the first adherend and the second adherend to each other. The adhesive portion contains a cured product of the above-described adhesive composition.

[0089] Examples of the first adherend and the second adherend include organic materials such as polyolefin resin, polyamide resin, ABS (acrylonitrile-butadiene-styrene) resin, PC (polycarbonate) resin, PET (polyethylene terephthalate) resin, PPS (polyphenylene sulfide) resin, acrylic resin, and transparent resin; inorganic materials such as steel, stainless steel, a single metal (such as aluminum, copper, nickel, chromium, etc.) or an alloy of these metals, glass, and silicon wafer; wood; rubber, and the like. Further, examples of the first adherend 1 and the second adherend 2 also include a material in which the above-described plastic and the above-described inorganic material are combined. Either the first adherend 1 or the second adherend 2 may be a transparent resin or glass from the viewpoint of light irradiation.

[0090] The thicknesses of the first adherend and the second adherend may be, for example, 0.1 to 2.0 mm, 0.1 to 1.0 mm, or 0.1 to 0.5 mm.

[0091] The adhesive body can be obtained, for example, by a method including a step of applying an adhesive composition on a first adherend to form an adhesive portion containing the adhesive composition, a step of disposing a second adherend on the adhesive portion precursor to produce a laminate, and a step of forming an adhesive portion containing a cured product of the adhesive composition by irradiating light on the adhesive portion of the laminate.

[0092] The adhesive composition can be applied using a knife coater, a roll coater, an applicator, a comma coater, a die coater, a dispenser, or the like.

[0093] The light irradiation conditions (such as the wavelength of light, light source, integrated light amount, etc.) for the adhesive portion of the laminate may be the same as the above-described light irradiation conditions (such as the wavelength of light, light source, integrated light amount, etc.).

[0094] The thickness of the bonding part containing the cured product of the adhesive composition may be, for example, 0.01 to 1.0 mm, 0.01 to 0.5 mm, or 0.01 to 0.2 mm.

Examples

[0095] Hereinafter, the present disclosure will be specifically described by way of examples, but the present disclosure is not limited to these examples.

[0096] [Synthesis of (meth)acrylic resin (crosslinking agent)] The following raw materials were prepared. ·(Meth)acrylate compound M-3F: 2,2,2-trifluoroethyl methacrylate (Light Ester M-3F, Kyoeisha Chemical Co., Ltd.) TTA-15: 3,4-epoxycyclohexylmethyl methacrylate (manufactured by Sankyo Chemical Co., Ltd.) ·Thermal radical generator V-601: Dimethyl-2,2'-azobis(2-methylpropionate) (Fuji Film Wako Pure Chemical Industries, Ltd.) ·Solvent NPG(D): Neopentyl glycol diglycidyl ether (Epogoce NPG(D)) (manufactured by Yokkaichi Gosei Co., Ltd.)

[0097] <Production Example 1> 144.38 g of M-3F and 42.13 g of TTA-15 (molar ratio of M-3F / TTA-15 = 80% / 20%), 5.78 g of V-601, and 24.11 g of NPG(D) were mixed to prepare a mixture (a). Separately, 1.87 g of V-601 was dissolved in 7.46 g of NPG(D) to prepare a solution (b).

[0098] A flask equipped with a stirring device, a dropping funnel, a condenser, a thermometer, and a gas inlet tube was charged with 162.44 g of NPG (D), stirred while purging with gas under a nitrogen atmosphere, and heated to 85°C. Subsequently, the mixture (a) was dropped into the flask over 2 hours. After completion of the dropping, the mixture was stirred at 85°C for 20 minutes, then the solution (b) was added, and stirring was continued for another 7 hours. Then, while continuing stirring, it was cooled to room temperature (25°C) to obtain a solution containing the (meth)acrylic resin (crosslinking agent A) of Production Example 1. The solid content concentration was 50% by mass.

[0099] [Evaluation of (meth)acrylic resin (crosslinking agent)] [Measurement of viscosity (25°C)] The viscosity at 25°C of the solution containing the (meth)acrylic resin was measured using an E-type viscometer (manufactured by Toki Sangyo Co., Ltd., product name: VISCOMETER-TV22, applicable cone plate type rotor: 3°×R17.65) after setting the sample to 0.5 - 1.0 mL and measuring under the condition of a rotation speed of 10 rpm. The results are shown in Table 1.

[0100] [Measurement of weight average molecular weight (Mw)] As a sample for Mw measurement, a solution containing the (meth)acrylic resin was dissolved in tetrahydrofuran (THF) to prepare a 0.2% by mass THF solution. Mw was measured by gel permeation chromatography (GPC) method and derived by conversion using a calibration curve of standard polystyrene. The conditions of GPC are shown below. Also, the results are shown in Table 1. Measuring device: SHODEX (registered trademark) GPC-101 (manufactured by Resonac Co., Ltd.) Detector: Differential refractometer SHODEX RI-71S (manufactured by Resonac Co., Ltd.) Column: SHODEX LF-804 + LF-804 (manufactured by Resonac Co., Ltd.) Column temperature: 40°C Eluent: Tetrahydrofuran (THF) Flow rate: 1 mL / min

[0101]

Table 1

[0102] [Preparation of Adhesive Composition] <Examples 1 to 8 and Comparative Example 1> The adhesive compositions of Examples 1 to 8 and Comparative Example 1 containing component (A), component (B), component (C), component (D), and component (E) were prepared by mixing each component in the amounts (unit: parts by mass) shown in Table 2 with a planetary mixer (5 minutes / 1500 rpm).

[0103] The details of each raw material are as follows. Component (A): (Meth)acrylate compound · Component (Aa): Monofunctional (meth)acrylate compound V-13F: 1H,1H,2H,2H-Tridecafluorooctyl acrylate (2-(Perfluorohexyl)ethyl acrylate) (manufactured by Osaka Organic Chemical Industry Co., Ltd.) 4-HBA: 4-Hydroxybutyl acrylate (manufactured by Osaka Organic Chemical Industry Co., Ltd.) 2-MTA: 2-Methoxyethyl acrylate (manufactured by Osaka Organic Chemical Industry Co., Ltd.) · Component (Ab): Polyfunctional (meth)acrylate compound A-9300S: Tris(2-acryloxyethyl)isocyanurate (trifunctional, EO-modified tri(meth)acrylate of isocyanuric acid, manufactured by Shin-Nakamura Chemical Co., Ltd.) M-402: Dipentaerythritol hexaacrylate (hexafunctional, manufactured by Toagosei Co., Ltd.) Component (B): Epoxy compound NPG(D): Neopentyl glycol diglycidyl ether (Epogoce NPG(D)) (manufactured by Yokkaichi Gosei Co., Ltd.) 2021P: 3’,4’-Epoxycyclohexylmethyl-3,4-epoxycyclohexanecarboxylate (Celloxide 2021P, manufactured by Daicel Corporation) Component (C): Crosslinking agent Crosslinking agent A: (Meth)acrylic resin of Production Example 1 Component (D): Photoacid generator CPI-110P: Sulfonium salt (manufactured by San-Apro Ltd.) (Component (E): Silane coupling agent KBM-403: 3-Glycidoxypropyltrimethoxysilane (manufactured by Shin-Etsu Chemical Co., Ltd.) KBE-9007N: 3-Isocyanatopropyltriethoxysilane (manufactured by Shin-Etsu Chemical Co., Ltd.)

[0104] In addition, the addition amounts of the (meth)acrylic resin (crosslinking agent A) of Production Example 1, which is Component (C), and NPG(D), which is Component (B), were adjusted using the solution containing the (meth)acrylic resin (crosslinking agent) obtained above.

[0105] [Evaluation of Adhesive Composition] (Measurement of Shear Strength Before and After Damp Heat Test) A spacer film with a thickness of 50 μm was placed on a slide glass so that the dimensions were 5 mm in width × 5 mm and the thickness was 50 μm, and the adhesive composition was applied on the slide glass. On the applied adhesive composition, a glass chip with a width of 7 mm × 7 mm and a thickness of 1.0 mm was placed, and using an LED lamp (manufactured by Ushio Inc., wavelength: 365 nm), 30 mW / cm 2 , the adhesive composition was irradiated with light under the conditions of 30 seconds, and the sample after 270 seconds had elapsed after the light irradiation was used as a measurement sample. Note that a plurality of measurement samples were prepared for the measurement of the shear strength after the damp heat test. The shear strength was measured for the measurement samples using a bond tester (manufactured by Nordson, product name: DAGE4000) under the condition of a shear rate of 180 mm / min to measure the initial shear strength. Next, using a measurement sample different from the measurement sample used for the measurement of the initial shear strength, a damp heat test (durability test under the conditions of a temperature of 85°C, a humidity of 85%RH, and a time of 168 hours) was carried out in a thermo-hygrostat (manufactured by ETAC, product name: SXN402-E) to obtain a measurement sample after the damp heat test. For the measurement sample after the damp heat test, the same conditions as above were measured to measure the shear strength after the damp heat test. The results are shown in Table 2. Also, from the initial shear strength and the shear strength after the damp heat test, the strength retention rate (%) of the adhesive strength was determined based on the following formula. The results are shown in Table 2. Retention rate of strength of subsequent strength (%) = Shear strength after damp heat test / Initial shear strength × 100

[0106]

Table 2

[0107] As shown in Table 2, the adhesive compositions of Examples 1 to 8 containing the component (E) were superior in terms of the adhesive strength of the cured product after the damp heat test as compared with the adhesive composition of Comparative Example 1 not containing the component (E). Further, from the comparison between Examples 1 and 2 and Examples 3 to 8, it was found that the use of the component (Ab) as the component (A) tended to further improve the adhesive strength of the cured product after the damp heat test. Furthermore, from the comparison between Examples 2, 4, 6, 8 and Examples 1, 3, 5, 7, it was found that the use of the component (E) having an isocyanate group as the functional group tended to further improve the strength retention rate of the adhesive strength. From the above, it was confirmed that the adhesive composition of the present disclosure can provide a cured product having sufficient adhesive strength after the damp heat test.

Claims

1. A pressure-sensitive adhesive composition containing a (meth)acrylate compound, an epoxy compound, a crosslinking agent, a photoacid generator, and a silane coupling agent, wherein the (meth)acrylate compound includes a monofunctional (meth)acrylate compound, the monofunctional (meth)acrylate compound includes a (meth)acrylate having a fluorine-containing organic group, the crosslinking agent includes a (meth)acrylic resin having a first structural unit derived from a (meth)acrylate having a fluorine-containing organic group and a second structural unit derived from a (meth)acrylate having a cyclic ether group, a pressure-sensitive adhesive composition.

2. The pressure-sensitive adhesive composition according to claim 1, wherein the (meth)acrylate compound further includes a polyfunctional (meth)acrylate compound.

3. The pressure-sensitive adhesive composition according to claim 1, wherein the epoxy compound includes an aliphatic epoxy compound.

4. The pressure-sensitive adhesive composition according to claim 3, wherein the epoxy compound further includes an alicyclic epoxy compound.

5. An adherend including a first adherend, a second adherend, and an adhesive portion that adheres the first adherend and the second adherend to each other, wherein the adhesive portion contains a cured product of the pressure-sensitive adhesive composition according to any one of claims 1 to 4.

6. A method for producing an adherend, the method comprising the steps of: applying the pressure-sensitive adhesive composition according to any one of claims 1 to 4 to at least one of the first adherend and the second adherend; bringing the first adherend and the second adherend into contact with each other with the pressure-sensitive adhesive composition interposed therebetween; and curing the pressure-sensitive adhesive composition to form an adhesive portion that adheres the first adherend and the second adherend to each other.

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