Active energy ray-curable adhesive composition, hardened product, and adhesive sheet

Abstract

The present disclosure provides a living energy ray-curable adhesive composition which can exhibit a low dielectric constant, a cured product thereof, and an adhesive sheet having the cured product. The living energy ray-curable adhesive composition includes: (A) a polyurethane (meth) acrylate having two or more (meth) acryloyl groups which is a reaction product of (a1) a hydrogenated polybutadiene polyol, (a2) an aliphatic polyisocyanate, and (a3) a (meth) acrylate having an isocyanate group, (B) an alkyl mono(meth) acrylate in which the carbon number of an alkyl group is 4 or more and 18 or less, (C) a mono(meth) acrylate containing a primary hydroxyl group, (D) one or more selected from the group consisting of a hydrogenated polybutadiene polyol, a hydrogenated polybutadiene, a hydrogenated polyisoprene polyol, a hydrogenated polyisoprene, a hydrogenated terpene phenol resin, and a hydrogenated petroleum resin, and (E) a photopolymerization initiator.

Description

Technical Field

[0001] This disclosure relates to an active energy line curing adhesive composition, a cured product, and an adhesive sheet. Background Technology

[0002] In recent years, touchscreens with capacitive touch sensors have been advancing towards larger sizes, higher integration, and improved response speeds, resulting in greater functionality. To achieve these larger sizes and higher integrations, there is a growing demand for lightweighting and thinning of components used in touchscreens, such as adhesive layers. It is known that capacitive touchscreens alter the electrostatic capacitance, which affects the touchscreen's sensitivity, by changing the relative permittivity of the components used within the touchscreen and the film thickness. For example, simply thinning the adhesive layer of the touchscreen can change the electrostatic capacitance value, potentially requiring design changes or causing malfunctions. To address these issues, it is necessary to adjust the electrostatic capacitance value by lowering the dielectric constant of components such as adhesive layers. Furthermore, lower dielectric constants are expected to improve the touchscreen's response speed or sensitivity. In addition, such adhesive layers require not only strong adhesive properties but also excellent optical properties (transparency).

[0003] In contrast, Patent Document 1 discloses an adhesive comprising a (meth)acrylic polymer, which is obtained by polymerizing a monomeric component comprising a specific alkyl (meth)acrylate, with the goal of achieving an adhesive layer with a low dielectric constant.

[0004] [Existing technical documents]

[0005] [Patent Literature]

[0006] [Patent Document 1] Japanese Patent Application Publication No. 2012-246477 Summary of the Invention

[0007] [The problem the invention aims to solve]

[0008] The purpose of this disclosure is to provide an active energy line curing adhesive composition exhibiting good low dielectric constant, a cured product thereof, and an adhesive sheet having the cured product thereof.

[0009] [Technical means to solve the problem]

[0010] The inventors conducted intensive research to solve the aforementioned problem and discovered that the problem could be solved by using a prescribed active energy line curing adhesive composition, its cured form, and an adhesive sheet having the cured form, thus completing the present invention.

[0011] That is, the present invention relates to the following items 1 to 7.

[0012] (Project 1)

[0013] An active energy line curing adhesive composition, characterized in that it comprises:

[0014] (A) A polyurethane (meth)acrylate having two or more (meth)acryloyl groups as a reaction product of (a1) hydrogenated polybutadiene polyol, (a2) aliphatic polyisocyanate and (a3) ​​(meth)acrylate having an isocyanate group.

[0015] (B) Alkyl mono(meth)acrylates with 4 or more but less than 18 carbon atoms.

[0016] (C) Mono(meth)acrylates containing primary hydroxyl groups,

[0017] (D) Selected from one or more of hydrogenated polybutadiene polyols, hydrogenated polybutadiene, hydrogenated polyisoprene polyols, hydrogenated polyisoprene, hydrogenated terpene phenolic resins, and hydrogenated petroleum resins, and

[0018] (E) Photopolymerization initiator

[0019] The proportions of components (A), (B), (C), and (D) relative to a total of 100% mass are 25%–60% mass, 15%–65% mass, 1%–5% mass, and 0.5%–55% mass, respectively.

[0020] (Project 2)

[0021] According to the active energy line hardening adhesive composition of Project 1, wherein the weight average molecular weight (converted to polystyrene by gel permeation chromatography) of component (A) is 10,000 to 60,000.

[0022] (Project 3)

[0023] According to the active energy line hardening adhesive composition of Project 1 or Project 2, wherein the average functional group number of component (A) is 2.0 to 4.0.

[0024] (Project 4)

[0025] The active energy line curing adhesive composition according to any one of Projects 1 to 3, wherein component (B) is selected from...

[0026] (b1) Alkyl mono(meth)acrylates with 4 or more but less than 18 carbon atoms in a straight-chain alkyl group without an alicyclic structure.

[0027] (b2) Alkyl mono(meth)acrylates with 4 or more but less than 18 carbon atoms, without alicyclic branched alkyl groups, and

[0028] (b3) One or more alkyl mono(meth)acrylates containing an alkyl group having 6 or more and 15 or fewer carbon atoms.

[0029] (Project 5)

[0030] A hardener is a hardener of an active energy line hardening adhesive composition according to any one of items 1 to 4.

[0031] (Project 6)

[0032] According to the hardened material described in Project 5, the dielectric constant at 25°C and 10kHz is less than 3.2.

[0033] (Project 7)

[0034] An adhesive sheet having a hardened material according to item 5 or item 6 on at least one side of a substrate surface.

[0035] [The effects of the invention]

[0036] The adhesive layer (hereinafter also referred to as "the hardened layer") of the active energy line hardening adhesive composition disclosed herein has a particularly excellent low dielectric constant. Attached Figure Description

[0037] none Detailed Implementation

[0038] In this disclosure as a whole, the ranges of various physical property values, contents, etc., can be appropriately set (for example, by selecting from the upper and lower limits described in the following items). Specifically, regarding the value α, if A1, A2, A3, etc. can be exemplified as the lower limit of the value α, and B1, B2, B3, etc. can be exemplified as the upper limit of the value α, the range of the value α can be A1 or above, A2 or above, A3 or above, B1 or below, B2 or below, B3 or below, A1 to B1, A1 to B2, A1 to B3, A2 to B1, A2 to B2, A2 to B3, A3 to B1, A3 to B2, A3 to B3, etc. Furthermore, the term "~" in this disclosure is used to mean the lower and upper limits, including the values ​​described before and after it. Hereinafter, the components of the active energy line curing adhesive composition of this disclosure, its cured product, and the adhesive sheet having the cured product will be described in detail.

[0039] <(A)Component>

[0040] (A) is a polyurethane (meth)acrylate having two or more (meth)acryloyl groups as the reaction product of (a1) hydrogenated polybutadiene polyol (also referred to as "(a1) component" in this disclosure), (a2) aliphatic polyisocyanate (also referred to as "(a2) component" in this disclosure), and (a3) ​​(meth)acrylate having isocyanate groups (also referred to as "(a3) component" in this disclosure).

[0041] <(a1)Component>

[0042] By including hydrogenated polybutadiene polyol as component (a1) in component (A), the active energy line hardening adhesive composition exhibits excellent compatibility of the solution and the adhesive layer.

[0043] (a1) The ingredients may also be commercially available products. Examples of such products include: hydrogenated polybutadiene glycol (product names "NISSO-PB GI-1000", "NISSO-PB GI-2000", "NISSO-PB GI-3000", manufactured by Nippon Soda Co., Ltd.), (product names "Krasol HLBH-P2000", "Krasol HLBH-P3000", manufactured by CRAY VALLEY Co., Ltd.), etc.

[0044] Examples of the upper limit of the number average molecular weight (Mn) of component (a1) include 5,000, 4,500, 4,000, 3,500, 3,000, 2,500, 2,000, 1,500, etc., and examples of the lower limit include 4,500, 4,000, 3,500, 3,000, 2,500, 2,000, 1,500, 1,000, etc. In one embodiment, the number average molecular weight (Mn) of component (a1) is preferably around 1,000 to 5,000. When the number average molecular weight of component (a1) is less than the lower limit, the adhesive layer tends to harden; when the number average molecular weight of component (a1) exceeds the upper limit, the adhesive layer tends to soften. Therefore, within the preferred range, not only is there a tendency for good adhesion, but also an excellent tendency for step-following property (the characteristic of the adhesive layer to deform according to the shape of the step when applied to a step-shaped portion). In this disclosure, the number average molecular weight is a polystyrene conversion value obtained by gel permeation chromatography.

[0045] Examples of upper limits for the iodine value (Ig / 100g) of component (a1) include: 50, 45, 40, 35, 30, 25, 20, 15, etc., and examples of lower limits include: 45, 40, 35, 30, 25, 20, 15, 10, etc. In one embodiment, the lower the iodine value (Ig / 100g) of component (a1), the better the durability. In this disclosure, the iodine value is a value determined by the method described in Japanese Industrial Standards (JIS) K 0070-1992.

[0046] Examples of upper limits for the hydroxyl value (KOH mg / g) of component (a1) include 200, 150, 100, 90, 80, 70, 60, 50, 40, 30, 20, etc., and examples of lower limits include 150, 100, 90, 80, 70, 60, 50, 40, 30, 20, 10, etc. In one embodiment, for particularly excellent adhesion, the hydroxyl value (KOH mg / g) of component (a1) is preferably 20 to 100. In this disclosure, the hydroxyl value is a value determined by the neutralization titration method described in JIS K 0070-1992.

[0047] Examples of the upper limit for the number of hydroxyl groups in component (a1) include 3, 2.9, 2.8, 2.7, 2.6, 2.5, 2.4, 2.3, 2.2, 2.1, 2.0, 1.9, 1.8, 1.7, 1.6, etc., and examples of the lower limit include 2.9, 2.8, 2.7, 2.6, 2.5, 2.4, 2.3, 2.2, 2.1, 2.0, 1.9, 1.8, 1.7, 1.6, 1.5, etc. In one embodiment, for the sake of excellent adhesion layer step followability and processability, the number of hydroxyl groups in component (a1) is preferably 1.5 or more and 3 or less, more preferably 1.8 or more and 2.5 or less. In this disclosure, the number of hydroxyl groups can be determined by the method described in JIS K1557-1:2007. Specifically, the number of hydroxyl groups can be determined by acetylation.

[0048] The upper limit of the content (converted to solid content) of component (a1) relative to 100% mass of components (a1), (a2), and (a3) ​​can be exemplified as: 99% by mass, 98% by mass, 96% by mass, 94% by mass, 92% by mass, 90% by mass, 85% by mass, 80% by mass, 75% by mass, 70% by mass, 65% by mass, 60% by mass, 55% by mass, etc., and the lower limit can be exemplified as: 98% by mass, 96% by mass, 94% by mass, 92% by mass, 90% by mass, 85% by mass, 80% by mass, 75% by mass, 70% by mass, 65% by mass, 60% by mass, 55% by mass, 50% by mass, etc. In one embodiment, the content (converted to solid content) of component (a1) relative to 100% mass of components (a1), (a2), and (a3) ​​is preferably 50% by mass to 99% by mass. By ensuring that the content of component (a1) is within the stated range, the various properties of this disclosure can be better exhibited. When the content of component (a1) is above the stated lower limit, the adhesive layer exhibits a more suitable hardness, which is preferred.

[0049] <(a2) Components>

[0050] Component (a2) is an aliphatic polyisocyanate. Examples of components (a2) include: aliphatic diisocyanate, aliphatic triisocyanate, aliphatic tetraisocyanate, etc. Examples of components (a2) include: linear aliphatic polyisocyanate, branched aliphatic polyisocyanate, alicyclic aliphatic polyisocyanate, aromatic polyisocyanate, etc. Examples of linear aliphatic diisocyanates include: trimethylene diisocyanate, tetramethylene diisocyanate, 1,5-pentamethylene diisocyanate, hexamethylene diisocyanate, octamethylene diisocyanate, decamethylene diisocyanate, etc. Examples of branched aliphatic diisocyanates include: methyl 2,6-diisocyanatohexanoate, trimethylhexamethylene diisocyanate, etc. Examples of alicyclic aliphatic diisocyanates include: dicyclohexylmethane 4,4'-diisocyanate, isophorone diisocyanate, 1,3-bis(isocyanatomethyl)cyclohexane, cyclohexane-1,4-diylbis(methylene)diisocyanate, 1-methylcyclohexane-2,4-diyl diisocyanate, 1,4-cyclohexane diisocyanate, hydrogenated xylene diisocyanate, hydrogenated toluene diisocyanate, norbornene diisocyanate, etc. Examples of aromatic diisocyanates include: toluene diisocyanate, diphenylmethane diisocyanate, phenyl dimethyl diisocyanate, etc. Examples of linear aliphatic triisocyanates include: lysine triisocyanate, etc.

[0051] In terms of its excellent low dielectric properties, component (a2) is preferably an alicyclic aliphatic polyisocyanate, and more preferably an alicyclic aliphatic diisocyanate.

[0052] The upper limit of the mass ratio (converted to solid components, (a1) / (a2)) of component (a1) to component (a2) can be exemplified by: 30, 28, 26, 24, 22, 20, 18, 16, 14, 12, etc., and the lower limit can be exemplified by: 28, 26, 24, 22, 20, 18, 16, 14, 12, 10, etc. In one embodiment, the mass ratio (converted to solid components, (a1) / (a2)) of component (a1) to component (a2) is preferably 10 to 30. By making the mass ratio (converted to solid components, (a1) / (a2)) of component (a1) to component (a2) within the aforementioned range, the various properties of this disclosure can be better displayed. When the mass ratio of component (a1) to component (a2) is above the aforementioned lower limit, the adhesive layer has a more suitable hardness, and in addition, a low dielectric constant is also excellent, therefore it is preferred.

[0053] The upper limit of the content (converted to solid content) of component (a2) relative to 100% by mass of components (a1), (a2), and (a3) ​​can be exemplified as follows: 20% by mass, 18% by mass, 16% by mass, 14% by mass, 12% by mass, 10% by mass, 8% by mass, 6% by mass, 4% by mass, 2% by mass, etc. The lower limit can be exemplified as follows: 18% by mass, 16% by mass, 14% by mass, 12% by mass, 10% by mass, 8% by mass, 6% by mass, 4% by mass, 2% by mass, 1% by mass, etc. In one embodiment, the content (converted to solid content) of component (a2) relative to 100% by mass of components (a1), (a2), and (a3) ​​is preferably 1% by mass to 20% by mass. By keeping the content of component (a2) within the aforementioned range, the various properties of this disclosure can be better exhibited. When the content of component (a2) is below the aforementioned upper limit, the low dielectric constant of the adhesive layer is excellent and therefore preferred.

[0054] <(a3) component>

[0055] By including (meth)acrylate with isocyanate groups as component (a3) ​​in component (A), the solution and adhesive layer of the active energy line curing adhesive composition exhibit excellent compatibility. When the active energy line curing adhesive composition is manufactured without component (a3), poor curing occurs, and the adhesive layer becomes too soft at room temperature.

[0056] Examples of components (a3) ​​include: 2-isocyanoethyl (meth)acrylate, 1,1-(bis(meth)acryloyloxymethyl)ethyl isocyanate, etc.

[0057] (a3) The ingredients may also be commercially available products. Examples of such products include: 2-isocyanoethyl (meth)acrylate (product name "Karenz MOI", "Karenz AOI", manufactured by Showa Denko Co., Ltd.), 1,1-(bis(meth)acryloyloxymethyl)ethyl isocyanate (product name "Karenz BEI", manufactured by Showa Denko Co., Ltd.), etc.

[0058] The upper limit of the ratio (OH(a1) / NCO((a2)+(a3))) of the number of hydroxyl groups (OH(a1)) of component (a1) to the number of isocyanate groups (NCO((a2)+(a3))) of components (a2) and (a3) ​​can be exemplified as: 3.0, 2.8, 2.6, 2.4, 2.2, 2.0, 1.8, 1.6, 1.4, 1.2, 1.0, 0.8, etc., and the lower limit can be exemplified as: 2.8, 2.6, 2.4, 2.2, 2.0, 1.8, 1.6, 1.4, 1.2, 1.0, 0.8, 0.6, etc. In one embodiment, the ratio of the number of moles of hydroxyl groups (OH(a1)) in component (a1) to the number of moles of isocyanate groups (NCO((a2)+(a3))) in components (a2) and (a3) ​​(OH(a1) / NCO((a2)+(a3))) is about 0.6 to 3.0. By keeping the ratio within this range, the various properties of this disclosure can be better demonstrated.

[0059] The upper limit of the mass ratio (converted to solid components, (a1) / (a3)) of component (a1) to component (a3) ​​can be exemplified by: 90, 85, 80, 75, 70, 65, 60, 55, 50, 45, 40, 35, etc., and the lower limit can be exemplified by: 85, 80, 75, 70, 65, 60, 55, 50, 45, 40, 35, 30, etc. In one embodiment, the mass ratio (converted to solid components, (a1) / (a3)) of component (a1) to component (a3) ​​is preferably 30 to 90. By keeping the mass ratio (converted to solid components, (a1) / (a3)) of component (a1) to component (a3) ​​within the aforementioned range, the various properties of this disclosure can be better displayed. When the mass ratio of component (a1) to component (a3) ​​is above the aforementioned lower limit, the adhesive layer has a more suitable hardness, which is therefore preferred. When the mass ratio of component (a1) to component (a3) ​​is below the upper limit, the adhesive layer becomes more appropriately soft, which is therefore preferred.

[0060] The upper limit of the mass ratio (converted to solid components, (a2) / (a3)) of component (a2) to component (a3) ​​can be exemplified by: 10, 8, 6, 4, 2, 1, etc., and the lower limit can be exemplified by: 8, 6, 4, 2, 1, 0.5, etc. In one embodiment, the mass ratio (converted to solid components, (a2) / (a3)) of component (a2) to component (a3) ​​is preferably 0.5 to 10. By making the mass ratio (converted to solid components, (a2) / (a3)) of component (a2) to component (a3) ​​within the aforementioned range, the various properties of this disclosure can be better displayed. When the mass ratio of component (a2) to component (a3) ​​is below the aforementioned upper limit, the adhesive layer becomes more appropriately flexible, and the low dielectric constant is also excellent, and therefore is preferred.

[0061] The upper limit of the content (converted to solid content) of component (a3) ​​relative to 100% by mass of components (a1), (a2), and (a3) ​​can be exemplified by: 10% by mass, 8% by mass, 6% by mass, 4% by mass, 2% by mass, 1% by mass, 0.5% by mass, etc., and the lower limit can be exemplified by: 8% by mass, 6% by mass, 4% by mass, 2% by mass, 1% by mass, 0.5% by mass, 0.1% by mass, etc. In one embodiment, the content (converted to solid content) of component (a3) ​​relative to 100% by mass of components (a1), (a2), and (a3) ​​is preferably 0.1% by mass to 10% by mass. By keeping the content of component (a3) ​​within the aforementioned range, the various properties of this disclosure can be better exhibited. When the content of component (a3) ​​is above the aforementioned lower limit, the adhesive layer becomes appropriately softer, which is therefore preferred.

[0062] <Other additives that can be incorporated into ingredient (A)>

[0063] (A) The ingredients may also include various additives as needed. Additives may be any known additives. Additives may be used alone or in combination of two or more. Examples of additives include catalysts, crystallization nucleating agents, crystallization promoters, chain transfer agents, polymerization inhibitors, etc.

[0064] The manufacturing method of component (A) is not particularly limited, and various known methods for manufacturing polyurethanes can be used. Component (A) is obtained by reacting component (a1) with component (a2) to temporarily produce a polyurethane prepolymer (hereinafter referred to as component (A')) having one or more hydroxyl groups at the ends, and then reacting component (A') with component (a3). The reaction temperature and reaction time are not particularly limited, and are generally 70°C or higher and 85°C or lower, and 1 hour or higher and 5 hours or lower. Components (b1), (b2), or (b3) can be used as diluents when manufacturing the polyurethane resin, preferably components (b1) and (b2). Alternatively, when manufacturing component (A), a method in which components (a1), (a2), and (a3) ​​are reacted together can be used, but the former is preferred in terms of ease of controlling the weight average molecular weight of component (A).

[0065] Examples of the upper limit of the dielectric constant of component (A) at 25°C and 10kHz include 3.0, 2.8, 2.6, 2.4, 2.2, 2.0, etc., and examples of the lower limit include 2.8, 2.6, 2.4, 2.2, 2.0, 1.8, etc. In one embodiment, the dielectric constant of component (A) at 25°C and 10kHz is preferably around 1.8 to 3.0.

[0066] Examples of the upper limit for the weight average molecular weight of component (A) include 90,000, 80,000, 70,000, 60,000, 50,000, 40,000, 30,000, 20,000, etc., and examples of the lower limit include 80,000, 70,000, 60,000, 50,000, 40,000, 30,000, 20,000, 10,000, etc. In one embodiment, the weight average molecular weight of component (A) is preferably 10,000 or more and 90,000 or less, in terms of excellent adhesion and step followability of the adhesive layer. When the weight average molecular weight of component (A) is above the lower limit, there is a tendency for the adhesion of the adhesive layer to become stronger; when the weight average molecular weight of component (A) is below the upper limit, there is a tendency for the viscosity of the active energy line curing adhesive composition to be moderate, and it becomes easier to manufacture. In this disclosure, the weight-average molecular weight is a polystyrene conversion value obtained by gel permeation chromatography.

[0067] Examples of the upper limit of the average functional group number of component (A) include: 4.0, 3.8, 3.6, 3.4, 3.2, 3.0, 2.8, 2.6, 2.4, 2.2, 2.0, 1.8, 1.6, etc., and examples of the lower limit include: 3.8, 3.6, 3.4, 3.2, 3.0, 2.8, 2.6, 2.4, 2.2, 2.0, 1.8, 1.6, 1.5, etc. In one embodiment, the average functional group number of component (A) is preferably 1.5 to 4.0, more preferably 1.8 to 4.0, and even more preferably 2.0 to 4.0, with regard to improving the durability of the adhesive layer. In this disclosure, the average functional group number refers to the average number of (meth)acryloyl groups present in one molecule of component (A).

[0068] The upper limit of the content (converted to solid content) of component (A) relative to 100% by mass of components (A), (B), (C), and (D) can be exemplified as 60% by mass, 55% by mass, 50% by mass, 45% by mass, 40% by mass, 35% by mass, 30% by mass, etc., and the lower limit can be exemplified as 55% by mass, 50% by mass, 45% by mass, 40% by mass, 35% by mass, 30% by mass, 25% by mass, etc. In one embodiment, with regard to the excellent curing properties, adhesion, durability, and step followability of the active energy line curing adhesive composition, the content (converted to solid content) of component (A) relative to 100% by mass of components (A), (B), (C), and (D) is 25% by mass or more and 60% by mass or less.

[0069] <(B) Component>

[0070] By including an alkyl mono(meth)acrylate with 4 to 18 carbon atoms as component (B) in the active energy line curing adhesive composition, the solution compatibility, adhesive layer compatibility, and dielectric constant of the adhesive layer of the active energy line curing adhesive composition are excellent. Component (B) is preferably selected from one or more of components (b1), (b2), and (b3) described below.

[0071] <(b1) Components>

[0072] Component (b1) is an alkyl mono(meth)acrylate with 4 to 18 carbon atoms in a straight-chain alkyl group without an alicyclic structure. By using component (b1) in an active energy line curing adhesive composition, excellent step follow-through of the adhesive layer is achieved. Since the alkyl mono(meth)acrylate in component (b1) has less than 19 carbon atoms in its alkyl group, compatibility becomes good, making it easier to achieve the effects of this disclosure.

[0073] Examples of (b1) components include: butyl methacrylate, pentyl methacrylate, hexyl methacrylate, heptyl methacrylate, octyl methacrylate, nonyl methacrylate, decyl methacrylate, hexadecyl methacrylate, lauryl methacrylate, stearyl methacrylate, etc.

[0074] Examples of the upper limit for the number of carbon atoms in the linear alkyl group of component (b1) include 18, 17, 16, 15, 14, 13, 12, 11, 10, 9, 8, 7, 6, 5, etc., and examples of the lower limit include 17, 16, 15, 14, 13, 12, 11, 10, 9, 8, 7, 6, 5, 4, etc. In one embodiment, the number of carbon atoms in the linear alkyl group of component (b1) is 4 or more and 18 or less.

[0075] The upper limit of the content (converted to solid content) of component (b1) relative to 100% by mass of components (A), (B), (C), and (D) can be exemplified as 65% by mass, 60% by mass, 55% by mass, 50% by mass, 45% by mass, 40% by mass, 35% by mass, 30% by mass, 25% by mass, 20% by mass, 15% by mass, 10% by mass, etc., and the lower limit can be exemplified as 60% by mass, 55% by mass, 50% by mass, 45% by mass, 40% by mass, 35% by mass, 30% by mass, 25% by mass, 20% by mass, 15% by mass, 10% by mass, 5% by mass, etc. In one embodiment, for excellent adhesion of the adhesive layer's step followability, the content (converted to solid content) of component (b1) relative to 100% by mass of components (A), (B), (C), and (D) is preferably 5% by mass or more and 65% by mass or less.

[0076] <(b2) Components>

[0077] Component (b2) is an alkyl mono(meth)acrylate with 4 to 18 carbon atoms in a branched alkyl group without an alicyclic structure. By using component (b2) in the active energy line curing adhesive composition, excellent step follow-through of the adhesive layer is achieved. Since the alkyl mono(meth)acrylate in component (b2) has less than 19 carbon atoms in its alkyl group, compatibility becomes good, making it easier to achieve the effects of the present invention.

[0078] Examples of components (b2) include: isoamyl methacrylate, isooctyl methacrylate, isononyl methacrylate, isodecanyl methacrylate, isostearyl methacrylate, 2-ethylhexyl methacrylate, etc.

[0079] Examples of the upper limit for the number of carbon atoms in the branched alkyl group of component (b2) include 18, 17, 16, 15, 14, 13, 12, 11, 10, 9, 8, 7, 6, 5, etc., and examples of the lower limit include 17, 16, 15, 14, 13, 12, 11, 10, 9, 8, 7, 6, 5, 4, etc. In one embodiment, the number of carbon atoms in the branched alkyl group of component (b2) is 4 or more and 18 or less.

[0080] Compared to the total of 100% by mass of components (A), (B), (C), and (D), the upper limit of the content of component (b2) (converted to solid components) can be exemplified as: 65% by mass, 60% by mass, 55% by mass, 50% by mass, 45% by mass, 40% by mass, 35% by mass, 30% by mass, 25% by mass, 20% by mass, 15% by mass, 10% by mass, 5% by mass, etc., and the lower limit can be exemplified as: 60% by mass, 55% by mass, 50% by mass, 45% by mass, 40% by mass, 35% by mass, 30% by mass, 25% by mass, 20% by mass, 15% by mass, 10% by mass, 5% by mass, 1% by mass, etc. In one embodiment, for the purpose of excellent step followability of the adhesive layer, the content (converted to solid content) of component (b2) is preferably 1% or more and 65% or less relative to the total of 100% by mass of components (A), (B), (C) and (D).

[0081] <(b3)Component>

[0082] Component (b3) is an alkyl mono(meth)acrylate containing an alkyl group with 6 or more and 15 or fewer carbon atoms. By using component (b3) in an active energy line curing adhesive composition, excellent adhesion of the adhesive layer is achieved.

[0083] Examples of components (b3) include: cyclohexyl methacrylate, 3,3,5-trimethylcyclohexyl methacrylate, 4-tert-butylcyclohexyl methacrylate, isobornyl methacrylate, dicyclopentyl methacrylate, dicyclopentenyl methacrylate, etc.

[0084] Regarding the excellent adhesion of the adhesive layer, component (b3) is preferably selected from one or more of the group consisting of cyclohexyl methacrylate, 3,3,5-trimethylcyclohexyl methacrylate, 4-tert-butylcyclohexyl methacrylate, isobornyl methacrylate and dicyclopentyl methacrylate, more preferably isobornyl methacrylate and / or dicyclopentyl methacrylate.

[0085] Examples of the upper limit for the number of carbon atoms in the alkyl group containing the alicyclic structure of component (b3) include 15, 14, 13, 12, 11, 10, 9, 8, 7, etc., and examples of the lower limit include 14, 13, 12, 11, 10, 9, 8, 7, 6, etc. In one embodiment, the number of carbon atoms in the alkyl group containing the alicyclic structure of component (b3) is 6 or more and 15 or less.

[0086] Compared to the total of 100% by mass of components (A), (B), (C), and (D), the upper limit of the content of component (b3) (converted to solid components) can be exemplified as: 65% by mass, 60% by mass, 55% by mass, 50% by mass, 45% by mass, 40% by mass, 35% by mass, 30% by mass, 25% by mass, 20% by mass, 15% by mass, 10% by mass, 5% by mass, etc., and the lower limit can be exemplified as: 60% by mass, 55% by mass, 50% by mass, 45% by mass, 40% by mass, 35% by mass, 30% by mass, 25% by mass, 20% by mass, 15% by mass, 10% by mass, 5% by mass, 1% by mass, etc. In one embodiment, in terms of the excellent adhesion of the adhesive layer, the content (converted to solid content) of component (b3) is preferably 1% or more and 65% or less relative to the total of 100% by mass of components (A), (B), (C) and (D).

[0087] Examples of the upper limit of the dielectric constant of component (B) at 25°C and 10kHz include 5.0, 4.8, 4.6, 4.4, 4.2, 4.0, 3.8, 3.6, 3.4, and 3.2, while examples of the lower limit include 4.8, 4.6, 4.4, 4.2, 4.0, 3.8, 3.6, 3.4, 3.2, and 3.0. In one embodiment, the dielectric constant of component (B) at 25°C and 10kHz is preferably around 3.0 to 5.0.

[0088] In terms of both superior adhesion and the ability to follow the step of the adhesive layer, component (B) is particularly preferred to include one or more components selected from (b1) and (b2) and two or more components selected from (b3). The upper limit of the content ratio (mass ratio, solid content conversion, [one or more components selected from (b1) and (b2) / (b3) component]) of component (b3) can be exemplified as: 2.0, 1.8, 1.6, 1.4, 1.2, 1.0, 0.8, etc., and the lower limit can be exemplified as: 1.8, 1.6, 1.4, 1.2, 1.0, 0.8, 0.5, etc. In one embodiment, the content ratio (mass ratio, solid content conversion, [one or more selected from (b1) and (b2) / (b3)]) of one or more of the components (b1) and (b2) is preferably about 0.5 to 2.0.

[0089] The upper limit of the content ratio (mass ratio, solid content conversion, [(A) component / (B) component]) of component (A) to component (B) can be exemplified by: 3.0, 2.8, 2.6, 2.4, 2.2, 2.0, 1.8, 1.6, 1.4, 1.2, 1.0, 0.8, 0.5, 0.3, etc., and the lower limit can be exemplified by: 2.8, 2.6, 2.4, 2.2, 2.0, 1.8, 1.6, 1.4, 1.2, 1.0, 0.8, 0.5, 0.3, 0.1, etc. In one embodiment, the content ratio (mass ratio, solid content conversion, [(A) component / (B) component]) of component (A) to component (B) is preferably about 0.1 to 3.0.

[0090] The upper limit of the content (converted to solid content) of component (B) relative to 100% by mass of components (A), (B), (C), and (D) can be exemplified as 65% by mass, 60% by mass, 55% by mass, 50% by mass, 45% by mass, 40% by mass, 35% by mass, 30% by mass, 25% by mass, 20% by mass, etc., and the lower limit can be exemplified as 60% by mass, 55% by mass, 50% by mass, 45% by mass, 40% by mass, 35% by mass, 30% by mass, 25% by mass, 20% by mass, 15% by mass, etc. In one embodiment, for the sake of excellent adhesion and step followability of the adhesive layer, the content (converted to solid content) of component (B) relative to 100% by mass of components (A), (B), (C), and (D) is preferably 15% by mass or more and 65% by mass or less.

[0091] <(C) Ingredients>

[0092] By using a mono(meth)acrylate containing a primary hydroxyl group as component (C) in the active energy line curing adhesive composition, the curing properties of the active energy line curing adhesive composition are excellent, and the durability of the adhesive layer after the damp heat resistance test is excellent. When a mono(meth)acrylate without hydroxyl groups is used as a substitute for component (C), the durability after the damp heat resistance test or the haze value after the damp heat resistance test deteriorates. In addition, when a mono(meth)acrylate containing a secondary hydroxyl group is used as a substitute for component (C), the haze value after the damp heat resistance test deteriorates.

[0093] Examples of component (C) include: 2-hydroxyethyl (meth)acrylate, 4-hydroxybutyl (meth)acrylate, 6-hydroxyhexyl (meth)acrylate, cyclohexanediol mono(meth)acrylate, etc.

[0094] In terms of the excellent curing properties of the active energy line curing adhesive composition and the excellent durability of the adhesive layer after the damp heat resistance test, component (C) is preferably 2-hydroxyethyl (meth)acrylate and / or 4-hydroxybutyl (meth)acrylate.

[0095] Examples of the upper limit of the dielectric constant of component (C) at 25°C and 10kHz include 15.0, 14.5, 14.0, 13.5, 13.0, 12.5, 12.0, 11.5, 11.0, and 10.5, while examples of the lower limit include 14.5, 14.0, 13.5, 13.0, 12.5, 12.0, 11.5, 11.0, 10.5, and 10.0. In one embodiment, the dielectric constant of component (C) at 25°C and 10kHz is preferably around 10.0 to 15.0.

[0096] The upper limit of the content ratio (mass ratio, solid content conversion, [(A) component / (C) component]) of component (A) to component (C) can be exemplified by: 20, 18, 16, 14, 12, 10, 8, 6, 4, etc., and the lower limit can be exemplified by: 18, 16, 14, 12, 10, 8, 6, 4, 2, etc. In one embodiment, the content ratio (mass ratio, solid content conversion, [(A) component / (C) component]) of component (A) to component (C) is preferably around 2 to 20.

[0097] The upper limit of the content ratio (mass ratio, solid content conversion, [(B) component / (C) component]) of component (B) to component (C) can be exemplified as: 20, 18, 16, 14, 12, 10, 8, 6, 4, etc., and the lower limit can be exemplified as: 18, 16, 14, 12, 10, 8, 6, 4, 2, etc. In one embodiment, the content ratio (mass ratio, solid content conversion, [(B) component / (C) component]) of component (B) to component (C) can be exemplified as: 20, 18, 16, 14, 12, 10, 8, 6, 4, 2, etc.

[0098] (C) Components] are preferably around 2 to 20.

[0099] The upper limit of the content (converted to solid content) of component (C) relative to 100% by mass of components (A), (B), (C), and (D) can be exemplified by: 5% by mass, 4% by mass, 3% by mass, 2% by mass, etc., and the lower limit can be exemplified by: 4% by mass, 3% by mass, 2% by mass, 1% by mass, etc. In one embodiment, the content (converted to solid content) of component (C) relative to 100% by mass of components (A), (B), (C), and (D) is preferably 1% by mass or more and 5% by mass or less. When the content of component (C) is above the lower limit, the adhesive layer exhibits excellent durability after the damp heat resistance test. When the content of component (C) is below the upper limit, the dielectric constant of the adhesive layer can be maintained at a low level.

[0100] <(D) component>

[0101] The adhesive layer exhibits excellent dielectric constant by including one or more selected from hydrogenated polybutadiene polyol, hydrogenated polybutadiene, hydrogenated polyisoprene polyol, hydrogenated polyisoprene, hydrogenated terpene phenolic resin, and hydrogenated petroleum resin as component (D) in the active energy line curing adhesive composition. Component (D) can be used alone or in combination of two or more.

[0102] Hydrogenated polybutadiene may also be a commercially available product. Examples of such products include "NISSO-PB BI-2000" and "NISSO-PB BI-3000" (manufactured by Nippon Soda).

[0103] Hydrogenated polybutadiene polyols may also be commercially available products. Examples of such products include "NISSO-PBGI-1000", "NISSO-PB GI-2000", and "NISSO-PB GI-3000" (manufactured by Nippon Soda Co., Ltd.).

[0104] Hydrogenated polyisoprene polyols may also be commercially available products. Examples of such products include "EPOL" (manufactured by Idemitsu Kosan Co., Ltd.).

[0105] Hydrogenated polyisoprene may also be a commercially available product. Examples of such products include "Kuraprene LIR-290" (manufactured by Kuraray Co., Ltd.).

[0106] Examples of terpene phenol resins include: terpene phenol resins obtained by copolymerizing known terpenes (α-pinene, β-pinene, dipentene, etc.) with phenols; and substances obtained by increasing the molecular weight of terpene phenol resins (for example, see Japanese Patent Application Publication No. 2000-212534). Hydrogenated terpene phenol resins can be obtained by hydrogenating terpene phenol resins using known methods. Hydrogenated terpene phenol resins can also be commercially available products. Examples of such products include "YS Polystar UH" (manufactured by Yasuhara Chemical Co., Ltd.).

[0107] Examples of petroleum resins include: C9 series petroleum resins, C5 series petroleum resins, C5-C9 series petroleum resins, dicyclopentadiene resins, or substances obtained by modifying these resins with alcohols, phenols, organic acids, etc. Examples of organic acids used in modification include: α,β-unsaturated carboxylic acids such as maleic acid, fumaric acid, succinic acid, and sebacic acid, and their anhydrides; rosin resins; (meth)acrylic acid; phenols, etc. Examples of modification methods include: methods that react with organic acids after the manufacture of petroleum resins; methods that manufacture petroleum resins in the presence of organic acids, etc. Hydrogenated petroleum resins can be obtained by hydrogenating petroleum resins using known methods. Hydrogenated petroleum resins can also be commercially available products. Examples of such products include the product name "Alcon" (manufactured by Arakawa Chemical Industry Co., Ltd.).

[0108] Examples of the upper limit of the softening point (°C) of component (D) include: 200, 190, 180, 170, 160, 150, 140, 130, 120, 110, 100, 90, etc., and examples of the lower limit include: 190, 180, 170, 160, 150, 140, 130, 120, 110, 100, 90, 80, etc. In one embodiment, for the purpose of excellent durability, the softening point (°C) of component (D) is preferably around 90 to 200.

[0109] Examples of the upper limit of the dielectric constant of component (D) at 25°C and 10kHz include 2.5, 2.4, 2.3, 2.2, 2.1, 2.0, and 1.9, while examples of the lower limit include 2.4, 2.3, 2.2, 2.1, 2.0, 1.9, and 1.8. In one embodiment, the dielectric constant of component (D) at 25°C and 10kHz is preferably around 1.8 to 2.5.

[0110] The upper limit of the content (converted to solid content) of component (D) relative to 100% by mass of components (A), (B), (C), and (D) can be exemplified as 55% by mass, 50% by mass, 45% by mass, 40% by mass, 35% by mass, 30% by mass, 25% by mass, 20% by mass, 15% by mass, 10% by mass, 5% by mass, 1% by mass, etc., and the lower limit can be exemplified as 50% by mass, 45% by mass, 40% by mass, 35% by mass, 30% by mass, 25% by mass, 20% by mass, 15% by mass, 10% by mass, 5% by mass, 1% by mass, 0.5% by mass, etc. In one embodiment, with regard to the excellent dielectric constant of the active energy line curing adhesive composition, the content (converted to solid content) of component (D) relative to 100% by mass of components (A), (B), (C), and (D) is preferably 0.5% by mass or more and 55% by mass or less.

[0111] <(E) component>

[0112] The adhesive layer exhibits excellent curability by including a photopolymerization initiator as component (E) in the active energy line curing adhesive composition, and is therefore preferred.

[0113] Examples of photopolymerization initiators include free radical photopolymerization initiators, cationic photopolymerization initiators, and anionic photopolymerization initiators. Examples of free radical photopolymerization initiators include benzyl ketone type photopolymerization initiators, acylphosphine oxide type photopolymerization initiators, hydrogen-abstracting type photopolymerization initiators, and oxime ester type photopolymerization initiators. Examples of benzyl ketone type photopolymerization initiators include benzyl dimethyl ketals such as 2,2-dimethoxy-1,2-diphenylethane-1-one; α-hydroxybenzyl ketones such as 1-[4-(2-hydroxyethoxy)-phenyl]-2-hydroxy-2-methyl-1-propane-1-one and 2-hydroxy-1-{4-[4-(2-hydroxy-2-methyl-propanoyl)-benzyl]phenyl}-2-methyl-propane-1-one; and α-aminobenzyl ketones such as 2-methyl-1-(4-methylthiophenyl)-2-morpholinopropane-1-one. Examples of acylphosphine oxide-type photopolymerization initiators include 2,4,6-trimethylbenzoyl-diphenylphosphine oxide and bis(2,4,6-trimethylbenzoyl)-phenylphosphine oxide. Examples of hydrogen-abstracting photopolymerization initiators include methyl phenylglyoxylate. Examples of oxime ester-type photopolymerization initiators include 1,2-octanedione, 1-[4-(phenylthio)-,2-(O-benzoyl oxime)], acetone, 1-[9-ethyl-6-(2-methylbenzoyl)-9H-carbazole-3-yl]-,1-(O-acetyl oxime), etc. Examples of cationic photopolymerization initiators include iodonium, mixtures of (4-methylphenyl)[4-(2-methylpropyl)phenyl]-hexafluorophosphate (1-) and propylene carbonate, triarylsulfonium hexafluorophosphate, and triarylsulfonium tetra-(pentafluorophenyl)borate. Examples of anionic photopolymerization initiators include cobaltamine complexes, o-nitrobenzyl alcohol carbamate, and oxime esters.

[0114] The upper limit of the content (converted to solid content) of component (E) relative to 100% by mass of components (A), (B), (C), and (D) can be exemplified by: 5% by mass, 4% by mass, 3% by mass, 2% by mass, 1% by mass, 0.5% by mass, etc., and the lower limit can be exemplified by: 4% by mass, 3% by mass, 2% by mass, 1% by mass, 0.5% by mass, 0.1% by mass, etc. In one embodiment, for the purpose of excellent adhesion / durability of the active energy line curing adhesive composition, the content (converted to solid content) of component (E) relative to 100% by mass of components (A), (B), (C), and (D) is preferably 0.1% by mass or more and 5% by mass or less.

[0115] <Other compatible additives>

[0116] The active energy line curing adhesive composition may contain various additives as needed. Additives may be used alone or in combination of two or more. Examples of additives include: surface conditioners, surfactants, UV absorbers, antioxidants, light stabilizers, adhesion promoters, inorganic fillers, silane coupling agents, colloidal silica, defoamers, wetting agents, rust inhibitors, chain transfer agents, photosensitizers, etc.

[0117] The active energy line hardening adhesive composition may contain an organic solvent. Examples of organic solvents include: ketone solvents, aromatic solvents, alcohol solvents, glycol solvents, glycol ether solvents, ester solvents, haloalkane solvents, amide solvents, and other petroleum-based solvents.

[0118] Examples of ketone solvents include methyl ethyl ketone, acetylacetone, methyl isobutyl ketone, cyclopentanone, and cyclohexanone.

[0119] Examples of aromatic solvents include toluene, xylene, and products named "T-SOL 100" and "T-SOL 150" (both manufactured by JXTG Energy).

[0120] Examples of alcohol solvents include methanol, ethanol, n-propanol, isopropanol, butanol, benzyl alcohol, and cresol.

[0121] Examples of glycol solvents include ethylene glycol, propylene glycol, diethylene glycol, dipropylene glycol, triethylene glycol, tripropylene glycol, polyethylene glycol, and polypropylene glycol.

[0122] Examples of glycol ether solvents include: ethylene glycol dimethyl ether, ethylene glycol diethyl ether, propylene glycol dimethyl ether, propylene glycol diethyl ether, diethylene glycol dimethyl ether, triethylene glycol dimethyl ether, diethylene glycol methyl ethyl ether, diethylene glycol diethyl ether, propylene glycol monomethyl ether, ethylene glycol monomethyl ether, ethylene glycol monoethyl ether, ethylene glycol mono-n-propyl ether, ethylene glycol monoisopropyl ether, ethylene glycol mono-n-butyl ether, ethylene glycol monoisobutyl ether, ethylene glycol mono-tert-butyl ether, bis(2-methoxyethyl) ether, etc.

[0123] Examples of ester solvents include ethyl acetate, butyl acetate, methyl cellosol acetate, ethyl cellosol acetate, and propylene glycol monomethyl ether acetate.

[0124] Examples of haloalkane solvents include chloroform.

[0125] Examples of amide solvents include dimethylformamide, dimethylacetamide, N-methyl-2-pyrrolidone, and N-methylcaprolactam.

[0126] Examples of other petroleum-based solvents include dimethyl sulfoxide and methylcyclohexane.

[0127] Active energy line curing adhesive compositions can be used even without solvents. Therefore, from the viewpoint of controlling cost and environmental impact, active energy line curing adhesive compositions are preferably solvent-free.

[0128] Examples of upper limits for the dielectric constant of the active energy line curable adhesive composition at 25°C and 10kHz include 3.5, 3.4, 3.3, 3.2, 3.1, 3.0, 2.9, 2.8, 2.7, 2.6, and 2.5, while examples of lower limits include 3.4, 3.3, 3.2, 3.1, 3.0, 2.9, 2.8, 2.7, 2.6, 2.5, and 2.4. In one embodiment, the dielectric constant of the active energy line curable adhesive composition at 25°C and 10kHz is preferably 3.5 or less. Therefore, the adhesive sheet can preferably be used to suppress transmission loss.

[0129] The active energy line hardening adhesive composition can be obtained by mixing components (A), (B), (C), (D), and (E), as well as other configurable additives as needed. There is no particular order of mixing; the components can be mixed sequentially or all at once.

[0130] <Hardened material>

[0131] One aspect of this invention is the substance obtained by curing an active energy line hardening adhesive composition by irradiating it with active energy lines such as ultraviolet light. When the active energy line hardening adhesive composition contains a solvent, a drying treatment can be considered before ultraviolet irradiation.

[0132] Examples of ultraviolet light sources include ultraviolet irradiation devices with xenon lamps, high-pressure mercury lamps, and metal halide lamps. The irradiation intensity, cumulative light output, and delivery speed of the ultraviolet light in such devices are not particularly limited; typically, the irradiation intensity is 80 mW / cm². 2 Above and 160mW / cm 2 Below, the transmission speed is 3 m / min or higher but less than 50 m / min, and the cumulative light intensity is 100 mJ / cm². 2 Above 3,000 mJ / cm 2 the following.

[0133] Alternatively, the active energy line curing adhesive composition can be applied to various plastic film substrates to form a layer of the active energy line curing adhesive composition, and then the layer can be irradiated with ultraviolet light to obtain a cured product.

[0134] Examples of coating methods for active energy line curing adhesive compositions include bar coating, Mayer bar coating, air knife coating, gravure coating, reverse gravure coating, offset printing, flexographic printing, and screen printing.

[0135] Regarding the application rate, the usual dry weight is 1 g / m³. 2 Above and 1,000g / m 2 The following, preferably 3g / m 2 Above and 500g / m 2 The following range.

[0136] There is no particular limitation on the thickness of the hardened material, but in order to prevent the formation of bubbles, it is preferable that the dried coating film is 10 μm or more and 1,000 μm or less, more preferably 25 μm or more and 500 μm or less.

[0137] Examples of upper limits for the dielectric constant of the hardened material at 25°C and 10kHz include 3.2, 3.1, 3.0, 2.9, 2.8, 2.7, 2.6, and 2.5, while examples of lower limits include 3.1, 3.0, 2.9, 2.8, 2.7, 2.6, 2.5, and 2.4. In one embodiment, the dielectric constant of the hardened material at 25°C and 10kHz is preferably 3.2 or less. This allows the adhesive sheet to exhibit good transmission loss suppression.

[0138] <Adhesive Sheet>

[0139] As an example of the application of active energy line curing adhesive composition, coating between substrates of various known articles can be illustrated.

[0140] Examples of such articles include: mobile communication devices such as mobile phones and smartphones or their base station devices, network-related electronic devices such as servers / routers, the frames and displays of information terminals such as personal computers, and printed circuit boards of these articles. The adhesive layer is particularly preferred for use with displays for various information terminals (personal computers, smartphones, input boards, etc.) due to its good dielectric constant and good haze.

[0141] <Applicable substrates>

[0142] Examples of substrates for coating active energy line-curing adhesive compositions include: glass substrates, metal substrates, and plastic substrates. Examples of plastic substrates include thermoplastic substrates and thermosetting plastic substrates. Examples of thermoplastic substrates include general-purpose plastic substrates and engineering plastic substrates. Examples of general-purpose plastic substrates include olefin-based, polyester-based, acrylic-based, vinyl-based, and polystyrene-based substrates. Examples of olefin-based substrates include polyethylene, polypropylene, and norbornene. Examples of polyester-based substrates include polyethylene terephthalate (PET) and polyethylene naphthalate (PEN). Examples of acrylic-based substrates include polymethyl methacrylate (PMMA). Examples of vinyl-based substrates include polyvinyl chloride, polyvinylidene chloride, and polyvinyl alcohol. Examples of polystyrene-based materials include polystyrene (PS) resin, styrene-acrylonitrile (AS) resin, and styrene-butadiene-acrylonitrile (ABS) resin. Examples of engineering plastic substrates include general-purpose engineering plastics and super engineering plastics. Examples of general-purpose engineering plastics include polycarbonate and polyamide (nylon). Examples of super engineering plastics include polyether ether ketone (PEEK). Examples of thermosetting plastic substrates include polyimide, epoxy resin, and melamine resin. Examples of other plastic substrates include triacetyl cellulose resin. The plastic substrate can be a copolymer of the aforementioned plastics. The substrate disclosed herein can be a multilayer comprising multiple of the aforementioned substrates. Furthermore, the substrate can also be a surface-treated substrate (such as corona discharge). Examples of upper limits for the thickness of the substrate include 300 μm, 275 μm, 250 μm, 225 μm, 200 μm, 175 μm, 150 μm, 125 μm, 100 μm, 75 μm, 50 μm, 25 μm, and 10 μm, while examples of lower limits include 275 μm, 250 μm, 225 μm, 200 μm, 175 μm, 150 μm, 125 μm, 100 μm, 75 μm, 50 μm, 25 μm, 10 μm, and 1 μm. In one embodiment, the thickness of the substrate is preferably 1 μm to 300 μm, more preferably 25 μm to 250 μm, even more preferably 50 μm to 200 μm, particularly preferably 50 μm to 150 μm, and even more preferably 75 μm to 125 μm.

[0143] The adhesive layer is particularly preferred for optical applications due to its excellent transparency. That is, the adhesive layer is especially suitable for bonding optical substrates. The adhesive layer is suitable for use as an optically clear adhesive (hereinafter also referred to as "optical clear adhesive (OCA)"). There are no particular limitations on the optical substrate; various known substrates are acceptable. The optical substrate can be used alone or in combination with two or more types.

[0144] Examples of substrates for optical applications include: polyester films such as polyethylene terephthalate (PET), polybutylene terephthalate (PET), and polyethylene naphthalate (PEN); polyethylene films; polypropylene films; cellophane; diacetyl cellulose films; triacetyl cellulose films; acetyl cellulose butyrate films; polyvinyl chloride films; polyvinylidene chloride films; polyvinyl alcohol films; ethylene-vinyl acetate copolymer films; polystyrene films; polycarbonate films; polymethylpentene films; polysulfone films; polyetheretherketone films; polyethersulfone films; polyetherimide films; polyimide films; fluoropolymer films; polyamide films; acrylic resin films; norbornene resin films; cycloolefin resin films; and other plastic films, glass; tin-doped indium oxide films; indium tin oxide (ITO) films; and transparent conductive films.

[0145] Specifically, examples of combinations of adhesive layers and optical substrates include:

[0146] (1) Glass, adhesive layer, transparent conductive film (hereinafter also referred to as "ITO").

[0147] (2) Supporting film, adhesive layer, ITO

[0148] (3) Support film, adhesive layer, liquid crystal display

[0149] (4) Glass, adhesive layer, liquid crystal display

[0150] wait.

[0151] [Example]

[0152] The present invention will be described in more detail below by providing manufacturing examples, comparative manufacturing examples, embodiments, comparative examples, evaluation examples, and comparative evaluation examples, but the present invention is not limited to these embodiments. Furthermore, in the following description, parts and percentages refer to mass.

[0153] In this embodiment, the weight average molecular weight (Mw) was determined by gel permeation chromatography (GPC) under the following conditions.

[0154] (GPC measurement conditions)

[0155] Model: Product name "HLC-8220GPC" (manufactured by Tosoh Corporation)

[0156] Tube column: Product name "TSKgel G1000H" "TSKgel G2000H" (manufactured by Tosoh Corporation)

[0157] Developing solvent: Tetrahydrofuran

[0158] Flow rate: 0.6 mL / min

[0159] Measurement temperature: 40℃

[0160] Detector: Differential Refractive Index Detector (RI)

[0161] Standard: Monodisperse polystyrene

[0162] Sample: A 20 μL solution obtained by preparing a tetrahydrofuran solution with a concentration of 0.2% (based on solids content) from the resin and filtering the solution using a microfilter.

[0163] In each manufacturing example, the method for determining the NCO of the urethane prepolymer is as follows.

[0164] Main body of the measuring device: Automatic potentiometric titration apparatus (product name "AT-400", manufactured by Kyoto Electronics Industry Co., Ltd.)

[0165] Measurement sequence:

[0166] 1: Weigh the sample in the weighing bottle to a weight of 0.500g or more but less than 1.000g.

[0167] 2: Inject 10 mL of a 0.15 mol / L dibutylamine toluene solution.

[0168] 3: Place the weighing bottle containing the sample into the ultrasonic cleaner to completely dissolve the sample.

[0169] 4. Confirm that the sample is completely dissolved and let it stand for 15 minutes (in a place away from direct sunlight and heat).

[0170] 5. After 15 minutes, add 100 mL of isopropanol to the weighing bottle. Place the stirrer piece into the weighing bottle.

[0171] 6: Titrate with 0.1 mol / L hydrochloric acid solution (f = 1.00) to determine the NCO value.

[0172] Input the sample volume to be measured into the automatic titration device and perform the measurement. If the measurement difference is within 0.30, the measurement is considered acceptable. If the difference is greater than 0.30, perform another measurement to confirm that it is within 0.30.

[0173] <Manufacturing Example 1: (A-1) Preparation of Ingredients>

[0174] In a reaction apparatus equipped with a cooling pipe and a stirrer, 936 parts (0.47 mol) of hydrogenated polybutadiene polyol (manufactured by Nippon Soda, trade name "NISSO-PB GI-3000"), 44 parts (0.34 mol) of dicyclohexylmethane-4,4-diisocyanate, and 0.2 parts of tin octoate were added. The mixture was heated to 80°C and held at that temperature for 2 hours. The reaction was then confirmed to be complete by NCO determination, yielding a hydroxyl-terminated urethane oligomer as an intermediate. Subsequently, 20 parts (0.13 mol) of 2-isocyanoethyl methacrylate (product name "Karenz MOI", manufactured by Showa Denko) were added, and the mixture was held at 80°C for 2 hours. The reaction was then confirmed to be complete by NCO determination, thereby obtaining a polyurethane methacrylate oligomer with a weight average molecular weight of 22,000 and an average functional group number of 2.0 (hereinafter also referred to as "component A-1").

[0175] <Manufacturing Example 2 and Comparative Manufacturing Example 1: Preparation of Components (A-2) and (A-C1)>

[0176] The components were changed as described in Table 1, except that the process was carried out in the same manner as in Manufacturing Example 1.

[0177] [Table 1]

[0178]

[0179] The meanings of the terms used in Table 1 are as follows. Furthermore, the numerical values ​​for the components listed in the table are converted from solid component values. Additionally, the dielectric constant was determined using the same method as in the performance evaluation (2) described below.

[0180] GI-3000: Hydrogenated polybutadiene glycol (product name "NISSO-PB GI-3000", manufactured by Showa Denko Co., Ltd.)

[0181] PPG2000: Polypropylene glycol (product name "Polypropylene glycol, glycol type, 2,000", manufactured by Fujifilm and Koichi Pharmaceutical Co., Ltd.)

[0182] H12MDI: Dicyclohexylmethane-4,4-diisocyanate (manufactured by Tokyo Chemical Industry Co., Ltd.)

[0183] IPDI: Isophorone diisocyanate (manufactured by Tokyo Chemical Industry Co., Ltd.)

[0184] MOI: 2-Isocyanoethyl methacrylate (Product name "Karenz MOI", manufactured by Showa Denko Co., Ltd.)

[0185] HEA: Hydroxyethyl acrylate (manufactured by Osaka Organic Chemicals Co., Ltd.)

[0186] <Example 1: Preparation of Active Energy Line Hardening Adhesive Composition (1)>

[0187] 37 parts of component (A-1), 20 parts of 2-EHA as component (b2), 20 parts of isobornyl acrylate (product name "IBXA", manufactured by Osaka Organic Chemical Industry Co., Ltd.) as component (b3), 3 parts of 4-hydroxybutyl acrylate (product name "4HBA", manufactured by Mitsubishi Chemical Co., Ltd.) as component (C), 20 parts of P-100 as component (D), and 1 part of 2,4,6-trimethylbenzoyl-diphenylphosphine oxide (product name "Speedcure TPO", manufactured by DKSH Co., Ltd.) as component (E) were mixed to obtain an active energy line hardening adhesive composition (1).

[0188] <Examples 2 to 7 and Comparative Examples 1 to 5: Active Energy Line Curing Adhesive Compositions (2) to (7) and Active Energy Line Curing Adhesive Compositions (C1) to (C5)>

[0189] The components were changed as described in Tables 2 and 3, except that the process was carried out in the same manner as in Example 1.

[0190] <Performance Evaluation (1): Viscosity (mPa·s)>

[0191] The viscosities of the active energy line hardening adhesive compositions (1) to (7) and the active energy line hardening adhesive compositions (C1) to (C5) were measured at 25°C using a commercially available measuring instrument (product name "TVE-10 type viscometer", manufactured by Toki Sangyo Co., Ltd.).

[0192] <Performance Evaluation (2): Dielectric Constant (Solution)>

[0193] The dielectric constants of active energy line curing adhesive compositions (1) to (7) and active energy line curing adhesive compositions (C1) to (C5) at 25°C and 10 kHz were determined using a commercially available dielectric constant measuring device (product name "Model 871", manufactured by Rufuto Co., Ltd., Japan).

[0194] <Performance Evaluation (3): Compatibility (Solution)>

[0195] The compatibility of the active energy line curing adhesive compositions (1) to (7) and (C1) to (C5) was visually confirmed and evaluated according to the following criteria.

[0196] ○: The solution of the active energy line hardening adhesive composition is transparent, and no precipitates can be found in the solution.

[0197] ×: The solution of the active energy line hardening adhesive composition is whitened and / or has precipitates in the solution.

[0198] <Performance Evaluation (4): Dielectric Constant (Adhesive Layer)>

[0199] Any one of the active energy line curing adhesive compositions (1) to (7) and (C1) to (C5) is coated onto a 75 μm thick heavily peeled polyester film (product name "SP-PET-03-75BU", manufactured by Panac) with a cured adhesive layer thickness of 100 μm. A 38 μm thick lightly peeled polyester film (product name "SP-PET-01-38BU", manufactured by Panac) is then bonded onto the peeled surface of the active energy line curing adhesive composition coating. Subsequently, the film is subjected to high-pressure mercury lamp (100 mW / cm²) in the atmosphere. 2 900mJ / cm 2 The obtained coated film was irradiated with ultraviolet light to produce a laminated film containing an adhesive layer (lightly peeled polyester film / adhesive layer / heavily peeled polyester film). Next, a 1cm × 1cm test piece was cut from the laminated film. Then, the lightly peeled polyester film and the heavily peeled polyester film were peeled off from the test piece to obtain a sheet containing only the adhesive layer (adhesive layer (1) to adhesive layer (7) and adhesive layer (C1) to adhesive layer (C5)). For the obtained sample, the dielectric constant at 25°C and 10kHz was measured using a commercially available dielectric constant measuring device (product name "Keysight E4980A", manufactured by Keycom).

[0200] <Performance Evaluation (5): Compatibility (Adhesive Layer)>

[0201] Using a spectrophotometer (product name "U-3210 self-recording spectrophotometer", manufactured by Hitachi, Ltd.), the transmittance (%) of the adhesive layer in performance evaluation (4) was measured by irradiating it with light of wavelength 500 nm, and the compatibility was evaluated according to the following criteria.

[0202] ○:More than 85%

[0203] ×: Less than 85%

[0204] <Performance Evaluation (6): Haze Value (Before Damp Heat Resistance Test)>

[0205] A laminated film was prepared with a film thickness of 100 μm for the cured active energy line-curing adhesive composition as per performance evaluation (4). The lightly peeled polyester film was then peeled off and replaced with a 50 μm thick polyester film (product name "COSMOSHINE A-4300", manufactured by Toyobo Co., Ltd.). The film was then bonded using a 2 kg roller and left to stand for 2 hours. Subsequently, an 8 cm × 8 cm test piece was cut from the material, and the heavily peeled polyester film was peeled off, thus creating a single-sided adhesive sheet (COSMOSHINE A-4300 / adhesive layer). A single-sided adhesive sheet (adhesive layer / COSMOSHINE A-4300) (5cm×5cm×150μm) was stacked on a glass plate (10cm×10cm×2mm) and tightly bonded using a 2kg roller to create a laminate (COSMOSHINE A-4300 (50μm thick) / adhesive layer (100μm thick) / glass plate (2mm thick)) (laminate (1)~laminate (7) and laminate (C1)~laminate (C5)). The haze values ​​of laminate (1)~laminate (7) and laminate (C1)~laminate (C5) were measured according to JIS K 7136:2000 using a commercially available measuring machine (product name "HM-150 Haze / Transmittance Meter", manufactured by Murakami Color Technology Research Institute Co., Ltd.). Furthermore, the haze values ​​obtained include the haze values ​​of the substrate (COSMOSHINE A-4300 and the glass plate).

[0206] <Performance Evaluation (7): Haze Value (After Damp Heat Resistance Test)>

[0207] Using a commercially available measuring instrument (product name "HM-150 Haze / Transmittance Meter", manufactured by Murakami Color Technology Research Institute Co., Ltd.), the haze values ​​of laminates (1) to (7) and laminates (C1) to (C5) were measured according to JIS K 7136:2000 after standing for 500 hours in a constant temperature and humidity chamber at 85°C and 85% humidity. Furthermore, the obtained haze values ​​include the haze values ​​of the substrate (COSMOSHINE A-4300 and the glass plate).

[0208] <Performance Evaluation (8): Adhesion (N / 25mm)>

[0209] Laminates (1) to (7) and laminates (C1) to (C5) were left to stand for 24 hours at 25°C and 50% humidity. The adhesion (N / 25mm) was measured by peeling the single-sided adhesive sheet (adhesive layer / COSMOSHINE A-4300) from the glass plate at a speed of 300mm / min along a 180° direction. Commercially available equipment (product name "Tensilon Universal Testing Machine", manufactured by AND) was used for the measurement.

[0210] <Performance Evaluation (9): Durability (after damp heat test)>

[0211] Laminates (1) to (7) and laminates (C1) to (C5) were left to stand for 500 hours in a constant temperature and humidity chamber at 85°C and 85% humidity. The durability of the adhesive layer was then evaluated according to the following criteria.

[0212] ○: No peeling of the substrate, misalignment of the adhesive layer, air bubbles in the adhesive layer, or damage to the adhesive layer.

[0213] ×: At least one of the following defects: substrate peeling, adhesive layer misalignment, air bubbles in the adhesive layer, or adhesive layer breakage.

[0214] [Table 2]

[0215]

[0216]

[0217] [Table 3]

[0218]

[0219] The meanings of the terms used in Tables 2 and 3 are as follows.

[0220] LA: Lauryl acrylate (manufactured by Osaka Organic Chemicals Co., Ltd., dielectric constant: 3.6)

[0221] 2-EHA: 2-Ethylhexyl acrylate (Product name: "2-Ethylhexyl acrylate", manufactured by Mitsubishi Chemical Co., Ltd., dielectric constant: 4.3)

[0222] ISTA: Isostearyl acrylate (product name "ISTA", manufactured by Osaka Organic Chemicals, Ltd., dielectric constant: 3.3)

[0223] IBXA: Isoborneol acrylate (Product name "IBXA", manufactured by Osaka Organic Chemicals Co., Ltd., dielectric constant: 4.6)

[0224] 4-HBA: 4-Hydroxybutyl acrylate (product name "4-HBA", manufactured by Osaka Organic Chemicals Co., Ltd., dielectric constant: 13.3)

[0225] P-100: Hydrogenated petroleum resin (product name "Alcon P-100", manufactured by Arakawa Chemical Industry Co., Ltd., softening point (ring and ball method) 100±5℃, dielectric constant: 2.1)

[0226] P-140: Hydrogenated petroleum resin (product name "Alcon P-140", manufactured by Arakawa Chemical Industry Co., Ltd., softening point (ring and ball method) 140±5℃, dielectric constant: 2.1)

[0227] BI-2000: Hydrogenated polybutadiene (product name "NISSO-PB BI-2000", manufactured by Nippon Soda Co., Ltd., dielectric constant: 2.1)

[0228] TPO: 2,4,6-Trimethylbenzoyl-diphenylphosphine oxide (product name "Speedcure TPO", manufactured by DKSH Co., Ltd., Japan)

[0229] The dielectric constant of each component was determined using the same method as in performance evaluation (2).

Claims

1. A composition of an active energy line-curing adhesive, characterized in that... Include: (A) A polyurethane (meth)acrylate having two or more (meth)acryloyl groups as a reaction product of (a1) hydrogenated polybutadiene polyol, (a2) aliphatic polyisocyanate and (a3) ​​(meth)acrylate having isocyanate groups. (B) Alkyl mono(meth)acrylates with 4 or more but less than 18 carbon atoms. (C) Mono(meth)acrylates containing primary hydroxyl groups, (D) Selected from one or more of hydrogenated polybutadiene polyol, hydrogenated polybutadiene, hydrogenated polyisoprene polyol, hydrogenated polyisoprene, hydrogenated terpene phenolic resin, and hydrogenated petroleum resin, and (E) Photopolymerization initiator, Relative to the total mass of components (A), (B), (C), and (D), the respective percentages are 25%–60% by mass, 15%–65% by mass, 1%–5% by mass, and 0.5%–55% by mass, respectively. (B) The ingredients include: The alkyl mono(meth)acrylate is selected from one or more of the following: (b1) alkyl mono(meth)acrylates with 4 or more and 18 or fewer carbon atoms of a straight-chain alkyl group without an alicyclic structure, and (b2) alkyl mono(meth)acrylates with 4 or more and 18 or fewer carbon atoms of a branched-chain alkyl group without an alicyclic structure. (b3) Alkyl mono(meth)acrylates containing an alkyl group with 6 or more but less than 15 carbon atoms in an alicyclic structure, and The mass ratio of one or more of the components (b1) and (b2) to the component (b3) is 0.5 to 2.

0.

2. The active energy line curing adhesive composition according to claim 1, wherein, (A) The weight average molecular weight of the component is 10,000 to 60,000.

3. The active energy line curing adhesive composition according to claim 1 or 2, wherein, (A) The average functional group of the component is 2.0 to 4.

0.

4. A cured product, which is a cured product of the active energy line curing adhesive composition according to any one of claims 1 to 3.

5. The hardened material according to claim 4, wherein, The dielectric constant at 25℃ and 10 kHz is below 3.

2.

6. An adhesive sheet having a hardened material according to claim 4 or 5 on at least one surface of a substrate.

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