Adhesive, adhesive sheet, and method for producing adhesive

Abstract

The present invention provides: an adhesive agent which contains a cyclodextrin compound, has a gel fraction of 30% or less, has a loss tangent (tan [delta]) of 0.48-3.00 at 25 DEG C, or has a thickness of 500 [mu] m and a width of 10 mm, and has a thickness of 30 [mu] m or less; and an adhesive sheet (1A) which is provided with at least an adhesive agent layer (11) that is formed from the adhesive agent, said adhesive agent having a gel fraction of 30% or less, and having a loss tangent (tan [delta]) of 0.48-3.00 at 25 DEG C. And the maximum stress of 0.08 N / mm2 or more when the steel sheet is stretched to the elongation at break at a measured length of 20 mm and a tensile rate of 200 mm / min in an environment of 23 DEG C and 50% RH. The adhesive and the adhesive sheet 1A have excellent high-temperature adhesion and can be recycled.

Description

Technical Field

[0001] The present invention relates to an adhesive, an adhesive sheet, and a method for manufacturing an adhesive. Background Art

[0002] In recent years, the demand for building a recycling-based society has been increasing, and recyclability is required for various products and materials.

[0003] In response to this, a new type of material using cyclodextrin monomers has recently been proposed. Specifically, Patent Document 1 proposes a polymer material that includes a crosslinked polymer crosslinked by the interaction between a host group and a guest group. Among them, the host group is a monovalent group formed by removing one hydrogen atom or one hydroxyl group from cyclodextrin, and the above crosslinked polymer includes a specified repeating structural unit.

[0004] In addition, Patent Document 2 proposes an inclusion complex, which is a cyclodextrin monomer derivative formed by the host group of a monomer containing a host group and the guest group of a monomer containing a guest group. Among them, the monomer containing a host group has a (meth)acryloyl group, and the monomer containing a guest group is a specified monomer having a vinyl group.

[0005] Prior Art Documents

[0006] Patent Documents

[0007] Patent Document 1: Japanese Patent No. 6636610 Gazette

[0008] Patent Document 2: Japanese Patent No. 6239043 Gazette Summary of the Invention

[0009] (I) Technical Problems to be Solved

[0010] Based on the above background, it is desired that the adhesive layer of the adhesive sheet can also be recycled. In addition, there is no description of the adhesive layer of the adhesive sheet in Patent Documents 1 and 2, nor is there any mention of recyclability.

[0011] On the other hand, the adhesive sheet is used to fix various adherends, but depending on the use, it is sometimes required that even when exposed to high temperatures for a long time, the change in the bonding position is small.

[0012] The present invention has been completed in view of the above actual situation, and an object thereof is to provide an adhesive and an adhesive sheet having excellent high-temperature adhesion and recyclability, and a method for manufacturing an adhesive capable of manufacturing such an adhesive.

[0013] (II) Technical Solutions

[0014] In order to achieve the above object, first, the present invention provides an adhesive which contains a cyclodextrin compound and has a gel fraction of 30% or less, and the loss tangent tanδ of the adhesive at 25 °C is 0.48 or more and 3.00 or less (Invention 1).

[0015] Second, the present invention provides an adhesive which contains a cyclodextrin compound and has a gel fraction of 30% or less. When the adhesive is formed into a thickness of 500 μm and a width of 10 mm, and is extended to the elongation at break at a measurement length of 20 mm and a tensile speed of 200 mm / minute in an environment of 23 °C and 50% RH, the maximum stress is 0.08 N / mm 2 or more (Invention 2).

[0016] For the adhesives of the above inventions (Inventions 1 and 2), by making them contain a cyclodextrin compound and have a gel fraction of 30% or less, the solvent solubility becomes excellent, and the recycling of the adhesive can be realized. In addition, for the adhesives of the above inventions (Inventions 1 and 2), by making them contain a cyclodextrin compound and making the loss tangent tanδ at 25 °C or the above maximum stress satisfy the above values, even when exposed to high temperature for a long time, the change in the bonding position is small, and the high-temperature bonding property becomes excellent.

[0017] In the above inventions (Inventions 1 and 2), it is preferred that the loss tangent tanδ at 80 °C is 0.01 or more and 2.00 or less (Invention 3).

[0018] In the above inventions (Inventions 1 to 3), it is preferred that when formed into a thickness of 500 μm and a width of 10 mm, and extended to the elongation at break at a measurement length of 20 mm and a tensile speed of 200 mm / minute in an environment of 23 °C and 50% RH, the fracture energy is 0.80 MJ / m 3 or more (Invention 4).

[0019] In the above inventions (Inventions 1 to 4), it is preferred that the adhesive is an acrylic adhesive (Invention 5).

[0020] In the above inventions (Inventions 1 to 5), it is preferred that the adhesive contains a polymer having a main chain formed by copolymerizing an acrylic monomer and a cyclodextrin compound having a polymerizable group (Invention 6).

[0021] In the above inventions (Inventions 1 to 6), it is preferred that the adhesive contains an acrylic polymer and a cyclodextrin compound formed by acylating all the hydroxyl groups of cyclodextrin (Invention 7).

[0022] Third, the present invention provides an adhesive sheet which is an adhesive sheet having at least an adhesive layer, and is characterized in that the adhesive constituting the adhesive layer is the adhesive (Inventions 1 to 7) (Invention 8).

[0023] Fourth, the present invention provides a method for manufacturing an adhesive, which is a method for manufacturing the adhesive (Inventions 1 to 7), and is characterized in that an acrylic monomer and a cyclodextrin compound are completely cured at once (Invention 9).

[0024] Fifth, the present invention provides a method for manufacturing an adhesive, which is a method for manufacturing the adhesive (Inventions 1 to 7), and is characterized by comprising the following steps: a step of curing at least a cyclodextrin compound having a polymerizable group to obtain a primary cured product; a step of mixing an acrylic monomer, a cyclodextrin compound having a polymerizable group, and the primary cured product to obtain a secondary mixture; and a step of curing the secondary mixture to obtain a secondary cured product (Invention 10).

[0025] Sixth, the present invention provides a method for manufacturing an adhesive, which is a method for manufacturing the adhesive (Inventions 1 to 7), and is characterized by comprising the following steps: a step of mixing an acrylic monomer and a cyclodextrin compound to obtain a primary mixture; a step of curing the primary mixture to obtain a primary cured product; a step of mixing an acrylic monomer, a cyclodextrin compound, and the primary cured product to obtain a secondary mixture; and a step of curing the secondary mixture to obtain a secondary cured product (Invention 11).

[0026] Seventh, the present invention provides a method for manufacturing an adhesive, which is a method for manufacturing the adhesive (Inventions 1 to 7), and is characterized by comprising the following steps: a step of curing one or more acrylic monomers to obtain a primary cured product; a step of mixing at least a cyclodextrin compound and the primary cured product to obtain a secondary mixture; and a step of curing the secondary mixture to obtain a secondary cured product (Invention 12).

[0027] (III) Advantageous Effects

[0028] The adhesive and the adhesive sheet of the present invention have excellent high-temperature adhesiveness, and recycling of the adhesive can be achieved. In addition, according to the method for manufacturing the adhesive of the present invention, an adhesive having excellent high-temperature adhesiveness and capable of being recycled can be manufactured. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] Figure 1 is a cross-sectional view of an adhesive sheet according to an embodiment of the present invention.

[0030] Figure 2 is a cross-sectional view of an adhesive sheet according to another embodiment of the present invention. DETAILED DESCRIPTION OF THE INVENTION

[0031] Hereinafter, embodiments of the present invention will be described.

[0032] [Adhesive]

[0033] The adhesive of an embodiment of the present invention preferably contains a cyclodextrin compound, and the gel fraction is 30% or less. Moreover, the loss tangent tanδ at 25°C is preferably 0.48 or more and 3.00 or less, or when formed into a thickness of 500 μm and a width of 10 mm, and elongated to the elongation at break at a measurement length of 20 mm and a tensile speed of 200 mm / minute in an environment of 23°C and 50% RH, the maximum stress is 0.08 N / mm 2 or more, or simultaneously satisfies the above range of the loss tangent tanδ and the above range of the maximum stress.

[0034] In addition, the method for measuring the gel fraction in this specification is as shown in the test examples described later. Moreover, the methods for measuring the loss tangent tanδ and the storage modulus G' in this specification are as shown in the test examples described later. Furthermore, the details of the tensile test for measuring the maximum stress, fracture energy, and tensile elastic modulus in this specification are as shown in the test examples described later.

[0035] The adhesive of this embodiment contains a cyclodextrin compound, and the gel fraction is 30% or less, so the solvent solubility becomes excellent, and recycling of the adhesive can be achieved. That is, by immersing the adhesive of this embodiment in a specified solvent, etc., the adhesive will dissolve in the solvent and peel off from the substrate. The adhesive dissolved in the solvent can be reused by volatilizing the solvent.

[0036] The solvent for dissolving the adhesive (layer) during recycling is not particularly limited, and for example, aliphatic hydrocarbons such as hexane, heptane, and cyclohexane; aromatic hydrocarbons such as toluene and xylene; halogenated hydrocarbons such as dichloromethane and dichloroethane; alcohols such as methanol, ethanol, propanol, butanol, and 1-methoxy-2-propanol; ketones such as acetone, methyl ethyl ketone, 2-pentanone, isophorone, and cyclohexanone; esters such as ethyl acetate and butyl acetate; cellosolve-based solvents such as ethyl cellosolve, etc. can be used.

[0037] The adhesive of this embodiment contains a cyclodextrin compound, and by making the loss tangent tanδ at 25°C or the above maximum stress satisfy the above values, even when exposed to high temperatures for a long time, the change in the bonding position is small, and the high-temperature bonding property becomes excellent. Additionally, it is more preferable that both the loss tangent tanδ at 25°C and the above maximum stress satisfy the above values.

[0038] From the perspective of solvent solubility, the gel fraction of the adhesive in this embodiment is preferably 30% or less, more preferably 15% or less, particularly preferably 10% or less, further preferably 6% or less, preferably 4% or less, and preferably 2% or less. On the other hand, from the perspective of cohesion, the gel rate of the adhesive in this embodiment is preferably 0% or more, more preferably 0.1% or more.

[0039] The loss tangent tanδ of the adhesive in this embodiment at 25°C is preferably 0.48 or more and 3.00 or less. Thus, the high-temperature adhesion becomes excellent. From this perspective, the loss tangent tanδ at 25°C is more preferably 0.51 - 2.60, particularly preferably 0.55 - 2.20, further preferably 0.70 - 2.00, and preferably 0.80 - 1.80.

[0040] The maximum stress of the adhesive in this embodiment is preferably 0.08 N / mm 2 or more. Thus, the high-temperature adhesion becomes excellent. From this perspective, the above maximum stress is more preferably 0.1 - 30.0 N / mm 2 particularly preferably 0.5 - 10.0 N / mm 2 preferably 0.8 - 8.0 N / mm 2 further preferably 1.1 - 6.0 N / mm 2 or more, and preferably 1.0 - 4.5 N / mm 2 or more.

[0041] The loss tangent tanδ of the adhesive in this embodiment at 80°C is preferably 0.01 or more, more preferably 0.05 or more, particularly preferably 0.10 or more. In addition, the loss tangent tanδ at 80°C is preferably 2.00 or less, more preferably 1.50 or less, particularly preferably 1.20 or less. By making the loss tangent tanδ at 25°C and the loss tangent tanδ at 80°C both within the above ranges, the high-temperature adhesion becomes even more excellent. In addition, from the perspective of balancing high-temperature adhesion and solvent solubility, the loss tangent tanδ at 80°C is preferably 0.20 - 0.90, more preferably 0.30 - 0.60, and preferably 0.38 - 0.52.

[0042] When the adhesive in this embodiment is formed into a thickness of 500 μm and a width of 10 mm, and stretched to the elongation at break at a measurement length of 20 mm and a stretching speed of 200 mm / minute in an environment of 23°C and 50% RH, the breaking energy is preferably 0.80 MJ / m 3 or more, more preferably 1.2 MJ / m 3 or more, particularly preferably 2.0 MJ / m3 More preferably, it is 3.0 MJ / m or more 3 or more. Thus, the high-temperature adhesion becomes excellent. On the other hand, from the perspective of balancing high-temperature adhesion and solvent solubility, the above-mentioned fracture energy is preferably 100 MJ / m or less, 3 more preferably 50 MJ / m or less, 3 particularly preferably 30 MJ / m or less, 3 and further preferably 15 MJ / m or less. 3

[0043] When the adhesive of this embodiment is formed into a thickness of 500 μm and a width of 10 mm, and a tensile test is carried out at a measurement length of 20 mm and a tensile speed of 200 mm / minute in an environment of 23°C and 50% RH, the tensile elastic modulus is preferably 0.01 MPa or more, more preferably 0.10 MPa or more, particularly preferably 0.20 MPa or more, and further preferably 0.40 MPa or more, and preferably 0.50 MPa or more. Thus, the high-temperature adhesion becomes more excellent. On the other hand, from the perspective of balancing high-temperature adhesion and solvent solubility, the above-mentioned tensile elastic modulus is preferably 40 MPa or less, more preferably 20 MPa or less, particularly preferably 10 MPa or less, and further preferably 6 MPa or less.

[0044] The storage modulus G' of the adhesive of this embodiment at 25°C is preferably 1.0×10 4 ~1.0×10 8 Pa, more preferably 1.0×10 5 ~1.0×10 7 Pa, particularly preferably 2.0×10 5 ~8.0×10 6 Pa, and further preferably 3.0×10 5 ~5.0×10 6 Pa. Thus, it becomes easier to meet the above physical properties, and further makes the high-temperature adhesion more excellent, and also makes it easier to balance the solvent solubility well.

[0045] The storage modulus G' of the adhesive of this embodiment at 80°C is preferably 1.0×10 4 ~1.0×10 6 Pa, more preferably 1.5×10 4 ~5.0×10 5 Pa, particularly preferably 3.0×10 4 ~1.0×10 5 Pa, and further preferably 5.0×10 4 ~9.0×10 4 ​Pa. Thus, it becomes easier to satisfy the above physical properties, and furthermore, the high-temperature adhesion becomes more excellent, and it also becomes easier to well balance the solvent solubility.

[0046] The adhesive of the present embodiment contains a cyclodextrin compound. The cyclodextrin compound in this specification may be cyclodextrin itself, a cyclodextrin having a substituent (cyclodextrin derivative), or a cyclodextrin or cyclodextrin derivative incorporated into a polymer (a polymer having cyclodextrin or cyclodextrin derivative as a structural monomer). In addition, the adhesive of the present embodiment is preferably a solvent-free adhesive. In addition, the adhesive of the present embodiment is preferably an acrylic adhesive, and particularly preferably a solvent-free acrylic adhesive.

[0047] The adhesive of the present embodiment preferably contains: a polymer having a main chain formed by copolymerizing an acrylic monomer and a cyclodextrin compound having a polymerizable group, or contains an acrylic polymer and cyclodextrin or a cyclodextrin derivative. In the latter case, a cyclodextrin derivative is more preferred than cyclodextrin. In addition, the cyclodextrin derivative is preferably a cyclodextrin derivative formed by substituting all hydroxyl groups of cyclodextrin with acyl groups, particularly acetyl groups. By having the above composition, it is possible to easily satisfy the above physical properties, and furthermore, the high-temperature adhesion becomes more excellent, and the adhesive dissolved in the solvent during recycling can be easily reused, making the recyclability of the adhesive more excellent.

[0048] The adhesive of the present embodiment preferably does not contain a guest molecule that can be included in the above cyclodextrin compound. In addition, in this specification, the term "inclusion" refers to the phenomenon in which a guest molecule is incorporated into the cavity inside the host molecule (cyclodextrin compound). In addition, in this specification, the term "guest molecule" refers to a molecule that can be included in a cyclodextrin compound, and also includes those that have not been included yet. As such guest molecules, for an α-cyclodextrin compound, n-butyl acrylate, styrene, octyl acrylate, and dodecyl acrylate can be listed; for a β-cyclodextrin compound, n-butyl acrylate, tert-butyl acrylate, styrene, adamantyl acrylate, and isobornyl acrylate can be listed; for a γ-cyclodextrin compound, octyl acrylate and dodecyl acrylate can be listed.

[0049] In addition, in this specification, the so-called adhesive "not containing guest molecules that can be included in the above-mentioned cyclodextrin compound" means substantially not containing. Specifically, relative to 100 moles of the total amount of acrylic monomers, the adhesive is allowed to contain 1 mole or less of guest molecules, preferably 0.1 mole or less, particularly preferably 0.01 mole or less, and further preferably 0.001 mole or less. There are cases where, for example, the above-listed monomers are used as acrylic monomers. These monomers will basically become polymers through polymerization and will not become guest molecules that can be included. However, sometimes a small amount will remain after polymerization. Therefore, the above regulations are made.

[0050] The above polymer having a main chain formed by copolymerizing an acrylic monomer and a cyclodextrin compound having a polymerizable group preferably does not have a branched structure. Thus, the resulting adhesive will not become too dense and will easily meet the above gel fraction.

[0051] First, the adhesive of this embodiment is preferably manufactured by the following method: using an acrylic monomer (A), a cyclodextrin compound having a polymerizable group (hereinafter sometimes referred to as "polymerizable cyclodextrin compound") (Bp), and a photoinitiator (C) which is preferably further contained, and copolymerizing the acrylic monomer (A) and the polymerizable cyclodextrin compound (Bp). In addition, second, the adhesive of this embodiment is preferably manufactured by the following method: using an acrylic monomer (A), a cyclodextrin compound not having a polymerizable group (hereinafter sometimes referred to as "non-polymerizable cyclodextrin compound") (Bn), and a photoinitiator (C) which is preferably further contained, and copolymerizing the acrylic monomer (A).

[0052] 1. Each component

[0053] (1) Acrylic monomer (A)

[0054] The acrylic monomer (A) in this embodiment is preferably a monofunctional acrylic monomer. Thus, the resulting polymer can be made to have no branched structure and will easily meet the above gel fraction.

[0055] In the adhesive of this embodiment, the acrylic monomer (A) can be used alone or in combination of two or more. First, it is preferred that the acrylic monomer (A) contains (meth)acrylate. (Meth)acrylate can be used alone or in combination of two or more. In addition, in this specification, the so-called (meth)acrylic acid means acrylic acid and methacrylic acid. The same applies to other similar terms.

[0056] As the (meth)acrylate, examples thereof include (meth)acrylic acid alkyl esters in which the alkyl group is linear or branched, (meth)acrylic acid esters having a cyclic structure such as an alicyclic structure, (meth)acrylic acid esters having a functional group such as a hydroxyl group, and the like. Among them, (meth)acrylic acid alkyl esters in which the alkyl group is linear or branched are preferred.

[0057] From the viewpoint of adhesiveness, the above-mentioned (meth)acrylic acid alkyl ester is preferably a (meth)acrylic acid alkyl ester having 1 to 20 carbon atoms in the alkyl group. Examples of the (meth)acrylic acid alkyl ester having 1 to 20 carbon atoms in the alkyl group include methyl (meth)acrylate, ethyl (meth)acrylate, propyl (meth)acrylate, n-butyl (meth)acrylate, n-pentyl (meth)acrylate, n-hexyl (meth)acrylate, 2-ethylhexyl (meth)acrylate, isooctyl (meth)acrylate, n-decyl (meth)acrylate, n-dodecyl (meth)acrylate, myristyl (meth)acrylate, palmityl (meth)acrylate, stearyl (meth)acrylate, and the like. Among them, from the viewpoint of obtaining good adhesiveness, (meth)acrylic acid esters having 1 to 8 carbon atoms in the alkyl group are preferred, and methyl (meth)acrylate, ethyl (meth)acrylate, n-butyl (meth)acrylate, 2-ethylhexyl (meth)acrylate, and the like are more preferred. In particular, from the viewpoint of easily satisfying the above physical properties, ethyl (meth)acrylate, n-butyl (meth)acrylate, and the like are preferred, and ethyl acrylate, n-butyl acrylate, and the like are further preferred.

[0058] The content of the above-mentioned (meth)acrylic acid alkyl ester in the acrylic monomer (A) is preferably 70 to 100% by mass, more preferably 75 to 99% by mass, particularly preferably 80 to 98% by mass, and further preferably 84 to 97% by mass when a nitrogen atom-containing monomer described later is included. Thereby, the above physical properties are within a more preferable range.

[0059] Second, the acrylic monomer (A) preferably contains a monomer containing a nitrogen atom in the molecule (nitrogen atom-containing monomer). Thereby, the above physical properties are within a more preferable range, and in particular, the high-temperature adhesion property becomes more excellent. The nitrogen atom-containing monomer is preferably used simultaneously with the above-mentioned (meth)acrylic acid alkyl ester.

[0060] Examples of the nitrogen atom-containing monomer include a monomer having an amino group, a monomer having an amide group, a monomer having a nitrogen-containing heterocycle, etc. Among them, from the viewpoint of easily satisfying the above physical properties, a monomer having an amide group is preferred. In addition, from the viewpoint of increasing the degree of freedom of the portion derived from the nitrogen atom-containing monomer in the higher-order structure of the resulting adhesive, it is preferred that the nitrogen atom-containing monomer does not contain a reactive unsaturated double bond group except for one polymerizable group used in the polymerization for forming the (meth)acrylate polymer (A). The nitrogen atom-containing monomer may be used alone or in combination of two or more.

[0061] Examples of the monomer having an amide group include (meth)acrylamide, N-methyl(meth)acrylamide, N,N-dimethyl(meth)acrylamide, N-ethyl(meth)acrylamide, N,N-diethyl(meth)acrylamide, N-hydroxymethyl(meth)acrylamide, N-tert-butyl(meth)acrylamide, N,N-dimethylaminopropyl(meth)acrylamide, N-isopropyl(meth)acrylamide, N-phenyl(meth)acrylamide, N-(n-butoxymethyl)(meth)acrylamide, dimethylaminopropyl(meth)acrylamide, N-vinylcaprolactam. Among them, from the viewpoint of more excellent high-temperature adhesion, N,N-diethyl(meth)acrylamide or N-isopropyl(meth)acrylamide is preferred, and N,N-diethylacrylamide or N-isopropylacrylamide is particularly preferred.

[0062] The content of the nitrogen atom-containing monomer (especially the monomer having an amide group) in the acrylic monomer (A) is preferably 1 to 30% by mass, more preferably 2 to 25% by mass, particularly preferably 3 to 20% by mass, and further preferably 4 to 16% by mass. Thereby, the above physical properties will be in a more preferable range, and in particular, the high-temperature adhesion will become more excellent.

[0063] The acrylic monomer (A) may contain an acrylic monomer other than the above monomers, for example, a carboxyl group-containing monomer such as (meth)acrylic acid, a hydroxyl group-containing monomer such as 2-hydroxyethyl (meth)acrylate, etc.

[0064] The content of the component derived from the acrylic monomer (A) in the adhesive of the present embodiment is preferably 70 to 99.99% by mass, more preferably 75 to 99.9% by mass, particularly preferably 80 to 99.6% by mass, and further preferably 90 to 99.2% by mass. Thereby, the above physical properties will be in a more preferable range.

[0065] (2) Polymerizable cyclodextrin compound (Bp)

[0066] In the present embodiment, the cyclodextrin moiety of the polymeric cyclodextrin compound (Bp) is preferably α-cyclodextrin, β-cyclodextrin or γ-cyclodextrin, and these cyclodextrin moieties may also have substituents. Among them, from the perspective of easily satisfying the above physical properties, β-cyclodextrin is preferred, and β-cyclodextrin having a substituent is particularly preferred.

[0067] The above-mentioned substituent is a group that replaces the hydroxyl group of the cyclodextrin. Examples of the above-mentioned substituent include an acyl group, an alkyl group, a trityl group, a toluenesulfonyl group, a trimethylsilyl group, a phenyl group, etc., as well as a polyester chain, an ethylene oxide chain, an alkyl chain, an ether chain, an ester chain, an acrylate chain, etc. Among them, from the perspective of easily obtaining an adhesive that satisfies the above physical properties, an acyl group is preferred, and an acetyl group is particularly preferred.

[0068] In the polymeric cyclodextrin compound (Bp), it is preferred that no hydroxyl group of the cyclodextrin remains, and it is preferred that all the hydroxyl groups of the cyclodextrin except for the part having a polymerizable group are substituted with an acyl group, particularly an acetyl group.

[0069] The polymerizable group possessed by the polymeric cyclodextrin compound (Bp) is not particularly limited as long as it can polymerize with the acryloyl group of the above-mentioned acrylic monomer (A). It is preferably a group containing a polymerizable unsaturated double bond, more preferably an ethylenically unsaturated group. Specifically, it is preferably a (meth)acryloyl group, a vinyl group, an allyl group, etc., and a (meth)acryloyl group is particularly preferred.

[0070] It is preferred that one polymerizable group is present in each molecule of cyclodextrin in the polymeric cyclodextrin compound (Bp). Thereby, the copolymer of the acrylic monomer (A) and the polymeric cyclodextrin compound (Bp) can be made to have no branched structure, and it becomes easy to satisfy the above-mentioned gel fraction.

[0071] From the above perspective, the content of the cyclodextrin compound having two or more polymerizable groups in each molecule in the adhesive is preferably as small as possible. Specifically, it is preferably 0.1% by mass or less, particularly preferably 0.01% by mass or less, and further preferably 0.001% by mass or less.

[0072] The polymeric cyclodextrin compound (Bp) in the present embodiment is preferably a compound represented by the following formula (1).

[0073] [Chemical formula 1]

[0074]

[0075] R in the above formula (1) 1 represents a hydrogen atom or a methyl group. R 2It represents O, NH, a hydrocarbon containing O, a hydrocarbon containing NH, or a hydrocarbon containing O and NH. CD represents α-cyclodextrin, β-cyclodextrin, γ-cyclodextrin, or their derivatives.

[0076] As the above-mentioned "hydrocarbon containing NH", for example, when bonded to CD on the right side, -CH2-NH-CH2-, -NH-CH2-O-CH2-, -O-CH2-NH-CH2-, -CH2-NH-CH2-O-, -O-CH2-NH-CH2-O-, -CH2-O-CO-NH-CH2-O-, -CH2-O-CO-NH-C2H4-O-, etc. can be cited. Among them, from the perspective of easily satisfying the above physical properties, -NH-CH2-O-CH2- is particularly preferred.

[0077] CD in the above formula (1) is preferably a derivative of β-cyclodextrin, and particularly preferably a β-cyclodextrin derivative formed by substituting all the hydroxyl groups of cyclodextrin with acyl groups, especially acetyl groups, except for the part bonded to R. 2

[0078] When the content of the component derived from the acrylic monomer (A) (the total amount of the acrylic monomer (A) when producing the adhesive) is set to 100 moles, the molar ratio of the content of the component derived from the polymerizable cyclodextrin compound (Bp) (the total amount of the polymerizable cyclodextrin compound (Bp) when producing the adhesive) in the adhesive of this embodiment is preferably 0.01 to 10, more preferably 0.05 to 6, particularly preferably 0.1 to 3, further preferably 0.3 to 2, and preferably 0.4 to 1.2. Thus, it becomes easier to satisfy the above physical properties, and the solvent solubility (recyclability) and high-temperature bonding property of the obtained adhesive become more excellent.

[0079] (3) Non-polymerizable cyclodextrin compound (Bn)

[0080] The cyclodextrin part of the non-polymerizable cyclodextrin compound (Bn) in this embodiment is preferably α-cyclodextrin, β-cyclodextrin, or γ-cyclodextrin, and these cyclodextrin parts may also have substituents (excluding polymerizable groups). Among them, from the perspective of easily satisfying the above physical properties, β-cyclodextrin is preferred, and β-cyclodextrin having substituents (excluding polymerizable groups) is particularly preferred.

[0081] The above-mentioned substituents are groups that substitute the hydroxyl groups of cyclodextrin, and specific examples thereof are the same as the specific examples of the substituents described for the polymerizable cyclodextrin compound (Bp).

[0082] In the non-polymerizable cyclodextrin compound (Bn), it is preferred that no hydroxyl groups of cyclodextrin remain, and it is particularly preferred that all the hydroxyl groups of cyclodextrin are substituted with acyl groups, especially acetyl groups. ​

[0083] When the content of the component derived from the acrylic monomer (A) (total amount of the acrylic monomer (A) used in producing the adhesive) is set to 100 moles, the molar ratio of the content of the component derived from the non-polymerizable cyclodextrin compound (Bn) (total amount of the non-polymerizable cyclodextrin compound (Bn) used in producing the adhesive) in the adhesive of the present embodiment is preferably from 0.01 to 10, more preferably from 0.05 to 6, particularly preferably from 0.1 to 3, still more preferably from 0.3 to 2, and preferably from 0.4 to 1.2. Thus, it becomes easier to satisfy the above physical properties, and the solvent solubility (recyclability) and high-temperature adhesiveness of the resulting adhesive become more excellent.

[0084] (4) Photoinitiator (C)

[0085] When ultraviolet rays are used as the active energy rays irradiated for copolymerizing the acrylic monomer (A) with the polymerizable cyclodextrin compound (Bp) or polymerizing the acrylic monomer (A), it is preferable to further use a photoinitiator (C) in producing the adhesive. By using the photoinitiator (C), the acrylic monomer (A) can be effectively copolymerized without remaining in the adhesive, and the polymerization curing time and the irradiation amount of the active energy rays can be reduced.

[0086] Examples of such photoinitiators include benzoin, benzoin methyl ether, benzoin ethyl ether, benzoin isopropyl ether, benzoin n-butyl ether, benzoin isobutyl ether, acetophenone, dimethylaminoacetophenone, 2,2-dimethoxy-2-phenylacetophenone, 2,2-diethoxy-2-phenylacetophenone, 2-hydroxy-2-methyl-1-phenylpropan-1-one, 1-hydroxycyclohexyl phenyl ketone, 2-methyl-1-[4-(methylthio)phenyl]-2-morpholinopropan-1-one, 4-(2-hydroxyethoxy)phenyl-2-(hydroxy-2-propyl)ketone, benzophenone, p-phenylbenzophenone, 4,4'-diethylaminobenzophenone, dichlorobenzophenone, 2-methylanthraquinone, 2-ethylanthraquinone, 2-tert-butylanthraquinone, 2-aminoanthraquinone, 2-methylthioxanthone, 2-ethylthioxanthone, 2-chlorothioxanthone, 2,4-dimethylthioxanthone, 2,4-diethylthioxanthone, benzil dimethyl ketal, acetophenone dimethyl ketal, p-dimethylaminobenzoate, oligomer [2-hydroxy-2-methyl-1-[4-(1-methylethenyl)phenyl]acetone], 2,4,6-trimethylbenzoyl diphenylphosphine oxide, phenylbis(2,4,6-trimethylbenzoyl)phosphine oxide, and the like. These photoinitiators can be used alone or in combination of two or more.

[0087] When the total amount of acrylic monomer (A) and polymerizable cyclodextrin compound (Bp) is 100 mol, the molar ratio of the amount of photoinitiator (C) used is preferably 0.001 to 10, more preferably 0.01 to 1, preferably 0.02 to 0.5, particularly preferably 0.05 to 0.3, and further preferably 0.1 to 0.2. Thus, the resulting adhesive becomes more likely to satisfy the above physical properties.

[0088] (5) Other components

[0089] The adhesive of the present embodiment may be blended with various additives commonly used in acrylic adhesives as required, such as silane coupling agents, rust inhibitors, ultraviolet absorbers, infrared absorbers, antistatic agents, thickeners, antioxidants, etc., light stabilizers, softeners, refractive index modifiers, colorants, fillers, etc.

[0090] 2. Manufacturing method

[0091] (1) In the case of using polymerizable cyclodextrin compound (Bp)

[0092] In the case of using polymerizable cyclodextrin compound (Bp), the adhesive of the present embodiment is preferably manufactured by copolymerizing acrylic monomer (A) and polymerizable cyclodextrin compound (Bp), and particularly preferably copolymerizing under solvent-free conditions. Specifically, it is preferably manufactured by the following method.

[0093] The first manufacturing method is a method of curing all of acrylic monomer (A) and polymerizable cyclodextrin compound (Bp) at once. When forming the adhesive layer, a mixed solution containing the total amount of acrylic monomer (A), the total amount of polymerizable cyclodextrin compound (Bp), and the photoinitiator (C) contained as required is coated on a desired object and cured to form the adhesive layer.

[0094] The curing of the mixed solution can be carried out by irradiating active energy rays or heat treatment, and is preferably carried out by irradiating active energy rays.

[0095] The so-called active energy rays refer to rays having energy quanta in electromagnetic waves or charged particle beams. Specifically, ultraviolet rays, electron beams, etc. can be cited. Among the active energy rays, ultraviolet rays that are easy to operate are preferred.

[0096] Ultraviolet rays can be irradiated using a high-pressure mercury lamp, an H lamp manufactured by Heraeus, a xenon lamp, etc. Regarding the irradiation amount of ultraviolet rays, the illuminance is preferably 50 to 1000 mW / cm 2 , and the light quantity is preferably 50 to 10000 mJ / cm 2 , more preferably 100 to 7000 mJ / cm2 , particularly preferably 200 to 4000 mJ / cm 2 . On the other hand, electron beam irradiation can be carried out by an electron beam accelerator or the like, and the irradiation dose of the electron beam is preferably 10 to 1000 krad.

[0097] The heating temperature of the heat treatment is preferably 60 to 150 °C, particularly preferably 80 to 120 °C. In addition, the heating time of the heat treatment is preferably 10 seconds to 10 minutes, particularly preferably 30 seconds to 5 minutes. This heat treatment can also serve as a drying treatment after coating the mixed solution.

[0098] In addition, when manufacturing the adhesive of this embodiment, active energy ray irradiation can be carried out after the heat treatment, or these two treatments can be carried out simultaneously.

[0099] The second manufacturing method is a method having the following steps: a step of obtaining a primary cured product (syrup) by curing at least the polymerizable cyclodextrin compound (Bp); a step of mixing the acrylic monomer (A), the polymerizable cyclodextrin compound (Bp), and the above primary cured product to obtain a secondary mixture; and a step of curing the secondary mixture to obtain a secondary cured product. In the step of obtaining the primary cured product, it is preferable to cure a primary mixture containing both the polymerizable cyclodextrin compound (Bp) and the acrylic monomer (A).

[0100] When forming the adhesive layer, first, a primary mixture containing a specified amount of the polymerizable cyclodextrin compound (Bp) and a specified amount of the acrylic monomer (A), a photoinitiator (C), etc. as required is prepared, and the primary mixture is cured to form a primary cured product (syrup). Then, the remaining amount of the acrylic monomer (A), the remaining amount of the polymerizable cyclodextrin compound (Bp), the above primary cured product, and the photoinitiator (C), etc. as required are mixed to form a secondary mixture (secondary mixed solution). This secondary mixture (secondary mixture solution) is coated on a desired object and cured to form an adhesive layer.

[0101] With respect to the total amount (100 mol%) of the polymerizable cyclodextrin compound (Bp), the blending amount of the polymerizable cyclodextrin compound (Bp) when preparing the primary mixture is preferably 1 mol% or more, more preferably 5 mol% or more, particularly preferably 15 mol% or more, further preferably 30 mol% or more, and, with respect to the upper limit, preferably 100 mol% or less. In addition, with respect to the total amount (100 mol%) of the acrylic monomer (A), the blending amount of the acrylic monomer (A) when preparing the primary mixture is preferably 0 to 80 mol%, particularly preferably 10 to 60 mol%, further preferably 20 to 50 mol%.

[0102] The curing method of the above-mentioned primary mixture and secondary mixture is the same as the above-mentioned first manufacturing method. However, when curing the primary mixture, regarding the irradiation amount of ultraviolet light, the illuminance is preferably 50 to 1000 mW / cm 2 , and the light amount is preferably 200 to 10000 mJ / cm 2 , particularly preferably 500 to 8000 mJ / cm 2 . In addition, when curing the secondary mixture, regarding the irradiation amount of ultraviolet light, the illuminance is preferably 50 to 1000 mW / cm 2 , and the light amount is preferably 200 to 20000 mJ / cm 2 , particularly preferably 500 to 10000 mJ / cm 2 .

[0103] The third manufacturing method is a method having the following steps: a step of curing one or more acrylic monomers (A) to obtain a primary cured product; a step of mixing at least a polymerizable cyclodextrin compound (Bp) with the above-mentioned primary cured product to obtain a secondary mixture; and a step of curing the secondary mixture to obtain a secondary cured product. In the step of obtaining the secondary mixture, it is preferable to mix the acrylic monomer (A), the polymerizable cyclodextrin compound (Bp), and the above-mentioned primary cured product simultaneously to obtain the secondary mixture.

[0104] When forming the adhesive layer, first, a primary mixture containing a specified amount of acrylic monomer (A) and a photopolymerization initiator (C) contained as required is prepared. In the third manufacturing method, the polymerizable cyclodextrin compound (Bp) is not blended at this time. Then, the primary mixture is cured to form a primary cured product (paste). Then, the remaining amount of acrylic monomer (A), polymerizable cyclodextrin compound (Bp), the above-mentioned primary cured product, and a photopolymerization initiator (C) contained as required are mixed to obtain a secondary mixture (secondary mixed solution). The secondary mixture (secondary mixture solution) is applied to a desired object and cured to form an adhesive layer.

[0105] Relative to the total amount (100 mol%) of the acrylic monomer (A), the blending amount of the acrylic monomer (A) when preparing the primary mixture is preferably 5 to 80 mol%, particularly preferably 10 to 60 mol%, and further preferably 20 to 50 mol%.

[0106] The curing method of the above-mentioned primary mixture and secondary mixture is the same as the above-mentioned second manufacturing method.

[0107] (2) Case of using a non-polymerizable cyclodextrin compound (Bn)

[0108] In the case of using a non-polymerizable cyclodextrin compound (Bn), the pressure-sensitive adhesive of the present embodiment is preferably produced by adding the non-polymerizable cyclodextrin compound (Bn) when polymerizing the acrylic monomer (A), and it is particularly preferably produced under solvent-free conditions. Specifically, it is preferably produced by the following method.

[0109] The first production method is a method of curing all of the acrylic monomer (A) at once. When forming the pressure-sensitive adhesive layer, a mixed solution containing the total amount of the acrylic monomer (A), the total amount of the non-polymerizable cyclodextrin compound (Bn), and a photopolymerization initiator (C) contained as required is coated on a desired object and cured to form the pressure-sensitive adhesive layer. The curing method is the same as in the case of using the polymerizable cyclodextrin compound (Bp).

[0110] The second production method is a method having the following steps: a step of curing a mixture of the acrylic monomer (A) and the non-polymerizable cyclodextrin compound (Bn) to obtain a primary cured product (paste); a step of mixing the acrylic monomer (A), the non-polymerizable cyclodextrin compound (Bn), and the above-mentioned primary cured product to obtain a secondary mixture; and a step of curing the secondary mixture to obtain a secondary cured product.

[0111] When forming the pressure-sensitive adhesive layer, first, a primary mixture containing a specified amount of the acrylic monomer (A), a specified amount of the non-polymerizable cyclodextrin compound (Bn), and a photopolymerization initiator (C) contained as required is prepared, and the mixed solution of the primary mixture is cured to form a primary cured product (paste). Then, the remaining amount of the acrylic monomer (A), the remaining amount of the polymerizable cyclodextrin compound (Bp), the above-mentioned primary cured product, and a photopolymerization initiator (C) contained as required are mixed to form a secondary mixture (secondary mixed solution). The secondary mixture (secondary mixture solution) is coated on a desired object and cured to form the pressure-sensitive adhesive layer.

[0112] With respect to the total amount (100 mol%) of the acrylic monomer (A), the blending amount of the acrylic monomer (A) when preparing the primary mixture is preferably 1 to 80 mol%, particularly preferably 10 to 60 mol%, and further preferably 20 to 50 mol%. In addition, with respect to the total amount (100 mol%) of the non-polymerizable cyclodextrin compound (Bn), the blending amount of the non-polymerizable cyclodextrin compound (Bn) when preparing the primary mixture is preferably 1 mol% or more, more preferably 5 mol% or more, particularly preferably 15 mol% or more, and further preferably 30 mol% or more in terms of the lower limit, and preferably 100 mol% or less in terms of the upper limit.

[0113] The curing methods of the above-mentioned primary mixture and secondary mixture are the same as those in the case of using the polymerizable cyclodextrin compound (Bp).

[0114] The third manufacturing method is a method comprising the following steps: a step of curing one or more acrylic monomers (A) to obtain a primary cured product; a step of mixing at least a non-polymerizable cyclodextrin compound (Bn) with the above-mentioned primary cured product to obtain a secondary mixture; and a step of curing the secondary mixture to obtain a secondary cured product. In the step of obtaining the secondary mixture, it is preferable to mix the acrylic monomer (A), the non-polymerizable cyclodextrin compound (Bn), and the above-mentioned primary cured product simultaneously to obtain the secondary mixture.

[0115] When forming the adhesive layer, first, a primary mixture containing a specified amount of the acrylic monomer (A) and a photopolymerization initiator (C) contained as required is prepared. In the third manufacturing method, the non-polymerizable cyclodextrin compound (Bn) is not blended at this time. Then, the primary mixture is cured to form a primary cured product (paste). Then, the remaining amount of the acrylic monomer (A), the non-polymerizable cyclodextrin compound (Bn), the above-mentioned primary cured product, and a photopolymerization initiator (C) contained as required are mixed to obtain a secondary mixture (secondary mixed solution). The secondary mixture (secondary mixture solution) is applied to a desired object and cured to form an adhesive layer.

[0116] With respect to the total amount (100 mol%) of the acrylic monomer (A), the blending amount of the acrylic monomer (A) when preparing the primary mixture is preferably 5 to 80 mol%, particularly preferably 10 to 60 mol%, and further preferably 20 to 50 mol%.

[0117] The curing methods of the above-mentioned primary mixture and secondary mixture are the same as those in the case of using the polymerizable cyclodextrin compound (Bp).

[0118] 4. Physical properties

[0119] (1) Measuring the gap ratio

[0120] An adhesive in the form of a cylinder with a diameter of 8 mm and a height of 800 μm is placed in a viscoelasticity tester. While continuously applying a force of 1 N to the adhesive in the vertical direction (the height direction of the adhesive), when heating from -20°C to 100°C at a heating rate of 4°C / min, the ratio of the measurement gap at 80°C to the measurement gap at 25°C is preferably 0.40 to 1.20, more preferably 0.50 to 1.15, particularly preferably 0.70 to 1.10, and further preferably 0.90 to 1.05. Thus, the shape of this adhesive changes little even at high temperatures, and the high-temperature adhesion property becomes excellent. In addition, the so-called measurement gap here refers to the distance between the measurement fixture and the Peltier module. The specific measurement method of the measurement gap is shown in the test examples described later.

[0121] (2) Displacement amount

[0122] An adhesive layer with a thickness of 50 μm and a size of 7 cm × 7 cm is attached to a soda-lime glass plate with a thickness of 1.1 mm and a size of 7 cm × 7 cm, and this is used as a sample. The above sample is attached to the vertically erected soda-lime glass plate and left standing at 80°C for 240 hours. The maximum value of the displacement amount at the left and right ends of the sample at this time is preferably 7.0 mm or less, more preferably 4.5 mm or less, particularly preferably 4.0 mm or less, and further preferably 3.0 mm or less, and preferably 1 mm or less. Thus, it can be said that the high-temperature adhesion property of this adhesive is excellent. In addition, the lower limit value of the above displacement amount is 0 mm. Furthermore, the specific measurement method of the above displacement amount is shown in the test examples described later.

[0123] [Adhesive sheet]

[0124] The adhesive sheet of one embodiment of the present invention includes at least an adhesive layer, and preferably a release sheet is laminated on one or both surfaces of the adhesive layer. The specific structure of an example of the adhesive sheet of this embodiment is shown in Figure 1 and Figure 2 .

[0125] As Figure 1 shown, the adhesive sheet 1A of the first embodiment is composed of a release sheet 12, an adhesive layer 11 laminated on the release surface of the release sheet 12, and a base material 13 laminated on the adhesive layer 11, starting from the bottom.

[0126] In addition, as Figure 2As shown, the adhesive sheet 1B of the second embodiment is composed of two release sheets 12a and 12b, and an adhesive layer 11 sandwiched between the two release sheets 12a and 12b in contact with the release surfaces of the two release sheets 12a and 12b. In addition, in this specification, the release surface of the release sheet refers to the surface having releasability in the release sheet, including the surface subjected to the release treatment and the surface showing releasability even without the release treatment.

[0127] Regardless of whether it is the adhesive sheet 1A or 1B, the adhesive layer 11 is formed of the above-mentioned adhesive. The thickness of the adhesive layer 11 (the value measured according to JIS K7130) can be appropriately determined according to the use purpose of the adhesive sheets 1A and 1B, but it is preferably 1 μm or more, more preferably 3 μm or more, particularly preferably 5 μm or more, further preferably 10 μm or more, and most preferably 15 μm or more. Thereby, good high-temperature adhesion can be exhibited. In addition, the thickness of the above-mentioned adhesive layer 12 is preferably 3000 μm or less, more preferably 1000 μm or less, particularly preferably 600 μm or less, further preferably 100 μm or less, and most preferably 50 μm or less. Thereby, the solvent solubility of the adhesive layer 12 becomes more excellent, and the recyclability of the adhesive becomes better. In addition, the above-mentioned adhesive layer 12 can be formed of a single layer or can be formed by laminating multiple layers.

[0128] There is no particular limitation on the base material 13, and all conventional materials used as the base material of the adhesive sheet can be used. For example, polyester films such as polyethylene terephthalate, polybutylene terephthalate, and polyethylene naphthalate can be mentioned; polyolefin films such as polyethylene film and polypropylene film; cellophane, diacetyl cellulose film, triacetyl cellulose film, cellulose acetate butyrate film, polyvinyl chloride film, polyvinylidene chloride film, polyvinyl alcohol film, ethylene-vinyl acetate copolymer film, polystyrene film, polycarbonate film, polymethylpentene film, polysulfone film, polyetheretherketone film, polyethersulfone film, polyetherimide film, fluororesin film, polyamide film, acrylic resin film, polyurethane resin film, norbornene-based polymer film, cyclic olefin-based polymer film, cyclic conjugated diene-based polymer film, vinyl norbornene polymer film, etc. plastic films or their laminated films; woven fabrics or non-woven fabrics using fibers such as rayon, acrylic, and polyester; papers such as high-grade paper, glassine paper, impregnated paper, and coated paper; metal foils such as aluminum and copper; foams such as urethane foam and polyethylene foam; laminates of two or more of the above materials, etc.

[0129] The base material 13 can be a desired optical member. As the optical member, for example, a polarizing plate (polarizing film), a polarizer, a retardation plate (retardation film), a viewing angle compensation film, a brightness enhancement film, a contrast enhancement film, a liquid crystal polymer film, a diffusion film, a semi-transmissive reflective film, etc. can be mentioned.

[0130] The thickness of the base material 13 varies depending on its type, use, etc., but is generally preferably 10 to 300 μm, particularly preferably 20 to 200 μm, and further preferably 30 to 100 μm.

[0131] The release sheets 12, 12a, 12b protect the adhesive layer 11 until the adhesive sheet 1 is used, and are peeled off when the adhesive sheet 1 (adhesive layer 11) is used.

[0132] As the release sheets 12, 12a, 12b, for example, a polyethylene film, a polypropylene film, a polybutene film, a polybutadiene film, a polymethylpentene film, a polyvinyl chloride film, a vinyl chloride copolymer film, a polyethylene terephthalate film, a polyethylene naphthalate film, a polybutylene terephthalate film, a polyurethane film, an ethylene vinyl acetate film, an ionomer resin film, an ethylene-(meth)acrylic acid copolymer film, an ethylene-(meth)acrylate copolymer film, a polystyrene film, a polycarbonate film, a polyimide film, a fluororesin film, etc. can be used. In addition, a crosslinked film of these films can also be used. In addition, a laminated film of these films can also be used.

[0133] Preferably, a release treatment is performed on the release surface of the release sheets 12, 12a, 12b (particularly the surface in contact with the adhesive layer 11). As the release agent used in the release treatment, for example, alkyd-based, silicone-based, fluorine-based, unsaturated polyester-based, polyolefin-based, wax-based release agents, etc. can be cited. In addition, preferably, one of the release sheets 12a, 12b is a heavy release type release sheet with a large release force, and the other release sheet is a light release type release sheet with a small release force.

[0134] The thickness of the release sheets 12, 12a, 12b is not particularly limited, but is generally preferably 20 to 200 μm, more preferably 30 to 120 μm.

[0135] When manufacturing the above-mentioned adhesive sheet 1A, preferably, the above-mentioned mixed liquid or secondary mixed liquid is applied to the release surface of the release sheet 12 to form a coating layer, and then the base material 13 is laminated on the coating layer, and then the coating layer is cured to form the adhesive layer 11. Or, the above-mentioned mixed liquid or secondary mixed liquid is applied to one surface of the base material 13 to form a coating layer, and then the release surface of the release sheet 12 is overlapped on the coating layer, and then the coating layer is cured to form the adhesive layer 11. The curing conditions are as described above.

[0136] In addition, when manufacturing the above-mentioned adhesive sheet 1B, the above-mentioned mixed liquid or secondary mixed liquid is applied to the release surface of one release sheet 12a (or 12b) to form a coating layer, and then the other release sheet 12b (or 12a) is overlapped on the coating layer, and then the coating layer is cured to form the adhesive layer 11.

[0137] As a method for coating the above-mentioned mixed liquid or secondary mixed liquid, for example, a bar coating method, a doctor blade coating method, a roll coating method, a blade coating method, a die coating method, a gravure coating method, etc. can be used.

[0138] The embodiments described above are described for the purpose of more easily understanding the present invention and are not intended to limit the present invention. Therefore, each element disclosed in the above embodiments is intended to include all design changes, equivalents, etc. belonging to the technical scope of the present invention.

[0139] For example, the release sheet 12 in the adhesive sheet 1A can be omitted, or either one of the release sheets 12a and 12b in the adhesive sheet 1B can be omitted.

[0140] In addition, in this specification, when "X~Y" (where X and Y are arbitrary numbers) is described, in the case of no special requirement, it means "X or more and Y or less", and at the same time, it also includes the meaning of "preferably larger than X" or "preferably smaller than Y". In addition, when "X or more" (where X is an arbitrary number) is described, in the case of no special requirement, it includes the meaning of "preferably larger than X"; when "Y or less" (where Y is an arbitrary number) is described, in the case of no special requirement, it includes the meaning of "preferably smaller than Y".

[0141] Examples

[0142] Hereinafter, the present invention will be described more specifically by way of examples and the like, but the scope of the present invention is not limited to these examples and the like.

[0143] [Production Example 1]

[0144] As the polymerizable cyclodextrin compound (Bp), the polymerizable β-cyclodextrin compound (Bp1) represented by the following formula (2) was produced according to the same procedure as in Production Example 6 of International Publication No. 2018 / 159791.

[0145] [Chemical Formula 2]

[0146]

[0147] In formula (2), Ac represents an acetyl group.

[0148] [Production Example 2]

[0149] As the polymerizable cyclodextrin compound (Bp), the polymerizable γ-cyclodextrin compound (Bp2) represented by the following formula (3) was produced according to the same procedure as in Production Example 7 of International Publication No. 2018 / 159791.

[0150] [Chemical Formula 3]

[0151]

[0152] In formula (3), Ac represents an acetyl group.

[0153] [Production Example 3]

[0154] As the non-polymeric cyclodextrin compound (Bn), the following non-polymeric β-cyclodextrin compound (Bn3) shown in formula (4) was produced according to the following steps.

[0155] 1.8 g of β-cyclodextrin (manufactured by Nacalai Tesque) and 47 mg of p-toluenesulfonic acid monohydrate as a catalyst were added to 8.5 ml of isopropyl acetate as a solvent, and the mixture was reacted at 70 °C for 16 hours. The reaction solution was removed by distillation under reduced pressure. The obtained solid was washed with a 10 mass% aqueous sodium carbonate solution, extracted with chloroform, and recrystallized with acetone to obtain 2.5 g of a white solid non-polymeric β-cyclodextrin compound (Bn3).

[0156] [Chemical Formula 4]

[0157]

[0158] In formula (4), Ac represents an acetyl group.

[0159] [Example 1]

[0160] 1. Preparation of the coating liquid of the adhesive composition

[0161] Ethyl acrylate and N-isopropylacrylamide as the acrylic monomer (A), the polymeric cyclodextrin compound (Bp1) produced in Production Example 1, and 1-hydroxycyclohexyl phenyl ketone as the photoinitiator (C) were mixed at the molar ratios shown in Table 1 and stirred well to obtain a mixed liquid.

[0162] 2. Production of the adhesive sheet

[0163] The mixed liquid obtained in Step 1 above was coated on the release-treated surface of a heavy-release type release sheet R1 formed by subjecting one surface of a polyethylene terephthalate film to a release treatment with a silicone-based release agent using a doctor blade coater.

[0164] Thereafter, the coated layer on the obtained release sheet R1 was adhered to a light-release type release sheet R2 formed by subjecting one surface of a polyethylene terephthalate film to a release treatment with a silicone-based release agent such that the release-treated surface of the release sheet R2 was in contact with the coated layer.

[0165] Thereafter, through the release sheet R2, active energy rays (ultraviolet rays; UV) were irradiated under the following conditions to cure the coating layer, thereby forming an adhesive layer with a thickness of 50 μm. Thus, an adhesive sheet having a structure of release sheet R2 / adhesive layer (thickness: 50 μm) / release sheet R1 was produced.

[0166] <Active energy ray irradiation conditions>

[0167] · Use a high-pressure mercury lamp

[0168] · The illuminance is 200 mW / cm 2 and the light quantity is 2000 mJ / cm 2

[0169] · The UV illuminance-light quantity meter used is "UVPF-A1" manufactured by EYE GRAPHICS

[0170] In addition, the thickness of the above-mentioned adhesive layer is the value measured using a constant-pressure thickness gauge (manufactured by Teclock, product name "PG-02") in accordance with JIS K7130 (the same applies hereinafter). Furthermore, when the release sheet is peeled off from the adhesive layer of the obtained adhesive sheet, the value of the peeling force of release sheet R1 is greater than that of release sheet R2.

[0171] [Examples 2, 4 to 6, Comparative Examples 2, 3, 5, 6]

[0172] Except that the types and blending amounts of the acrylic monomer (A) and the cyclodextrin compound (B) were changed as shown in Table 1, the adhesive sheet was produced in the same manner as in Example 1. In addition, in Comparative Example 5, the polymerizable γ-cyclodextrin compound (Bp2) produced in Production Example 2 was used as the cyclodextrin compound (B).

[0173] [Example 3]

[0174] Ethyl acrylate and N-isopropylacrylamide as the acrylic monomer (A) and 1-hydroxycyclohexyl phenyl ketone as the photoinitiator (C) were mixed in the molar ratios shown in Table 1 and stirred well to obtain a primary mixed solution.

[0175] The above-mentioned primary mixed solution was irradiated with active energy rays (ultraviolet rays; UV) under the following conditions to obtain a primary cured product (paste).

[0176] <Active energy ray irradiation conditions>

[0177] · Use a high-pressure mercury lamp

[0178] · The illuminance is 60 mW / cm 2 and the light quantity is 2000 mJ / cm 2

[0179] · The UV illuminance - light quantity meter uses "UVPF - A1" manufactured by EYE GRAPHICS

[0180] Next, the above - obtained primary cured product, ethyl acrylate as the acrylic monomer (A), N - isopropylacrylamide, the non - polymerizable β - cyclodextrin compound (Bn3) manufactured in Production Example 3, and 1 - hydroxycyclohexyl phenyl ketone as the photo - polymerization initiator (C) were mixed in the molar ratios shown in Table 1 and stirred well to obtain a secondary mixed solution.

[0181] The above - obtained secondary mixed solution was coated on the release - treated surface of the same release sheet R1 as the release sheet R1 used in Example 1 using a doctor coater.

[0182] After that, the coated layer on the release sheet R1 and the release sheet R2 same as the release sheet R2 used in Example 1 were laminated in such a way that the release - treated surface of the release sheet R2 was in contact with the coated layer.

[0183] After that, through the release sheet R2, active energy rays (ultraviolet rays; UV) were irradiated under the following conditions to cure the coated layer, thereby forming an adhesive layer with a thickness of 50 μm. Thus, an adhesive sheet having a structure of release sheet R2 / adhesive layer (thickness: 50 μm) / release sheet R1 was produced.

[0184] <Active energy ray irradiation conditions>

[0185] · A high - pressure mercury lamp was used

[0186] · The illuminance was 60 mW / cm 2 , and the light quantity was 2000 mJ / cm 2

[0187] · The UV illuminance - light quantity meter uses "UVPF - A1" manufactured by EYE GRAPHICS

[0188] [Example 7]

[0189] An adhesive sheet was produced in the same manner as in Example 3, except that the polymerizable β - cyclodextrin compound (Bp1) manufactured in Production Example 1 was used instead of the non - polymerizable β - cyclodextrin compound (Bn3) when preparing the secondary mixed solution.

[0190] [Example 8]

[0191] Ethyl acrylate as an acrylic monomer (A), the polymerizable β-cyclodextrin compound (Bp1) produced in Production Example 1, and 1-hydroxycyclohexyl phenyl ketone as a photoinitiator (C) were mixed at the molar ratios shown in Table 1 and stirred well to obtain a primary mixed solution.

[0192] The above primary mixed solution was irradiated with active energy rays (UV; ultraviolet rays) under the following conditions to obtain a primary cured product (paste).

[0193] <Active energy ray irradiation conditions>

[0194] ·Use a high-pressure mercury lamp

[0195] ·The illuminance is 60 mW / cm 2 and the light quantity is 2000 mJ / cm 2

[0196] ·The UV illuminance-light quantity meter used is "UVPF-A1" manufactured by EYE GRAPHICS Co., Ltd.

[0197] Thereafter, the primary cured product obtained above, ethyl acrylate as an acrylic monomer (A), and 1-hydroxycyclohexyl phenyl ketone as a photoinitiator (C) were mixed at the molar ratios shown in Table 1 and stirred well to obtain a secondary mixed solution.

[0198] The secondary mixed solution obtained above was coated on the release-treated surface of the same release sheet R1 as the release sheet R1 used in Example 1 using a doctor coater.

[0199] Thereafter, the coated layer on the release sheet R1 obtained above and the same release sheet R2 as the release sheet R2 used in Example 1 were adhered in such a manner that the release-treated surface of the release sheet R2 was in contact with the coated layer.

[0200] Thereafter, through the release sheet R2, active energy rays (ultraviolet rays; UV) were irradiated under the following conditions to cure the coated layer, thereby forming an adhesive layer with a thickness of 50 μm. Thus, an adhesive sheet having a structure of release sheet R2 / adhesive layer (thickness: 50 μm) / release sheet R1 was produced.

[0201] <Active energy ray irradiation conditions>

[0202] ·Use a high-pressure mercury lamp

[0203] ·The illuminance is 60 mW / cm 2 and the light quantity is 2000 mJ / cm 2

[0204] · The UV irradiance - light quantity meter uses "UVPF - A1" manufactured by EYE GRAPHICS

[0205] [Comparative Examples 1 and 4]

[0206] The adhesive sheet was produced in the same manner as in Example 8, except that the type and blending amount of the acrylic monomer (A) and the type and blending amount of the cyclodextrin compound (B) were changed as shown in Table 1. Additionally, in Comparative Example 4, the polymerizable γ - cyclodextrin compound (Bp2) produced in Production Example 2 was used as the cyclodextrin compound (B).

[0207] Details of the abbreviations and the like described in Table 1 are as follows.

[0208] [Acrylic monomer (A)]

[0209] EA: Ethyl acrylate

[0210] BA: n - Butyl acrylate

[0211] NiPAAm: N - Isopropylacrylamide

[0212] DEAA: N,N - Diethylacrylamide

[0213] DCP: Dimethylol tricyclodecane diacrylate

[0214] [Cyclodextrin compound (B)]

[0215] Bp1: Polymerizable β - cyclodextrin compound produced in Production Example 1

[0216] Bp2: Polymerizable γ - cyclodextrin compound produced in Production Example 2

[0217] Bn3: Non - polymerizable β - cyclodextrin compound produced in Production Example 3

[0218] [Test Example 1] (Measurement of gel fraction)

[0219] The adhesive sheets produced in the examples and comparative examples were cut into a size of 80 mm × 80 mm, and the adhesive layer was wrapped in a polyester mesh (mesh size 200). The mass was measured using an analytical balance, and the mass of the adhesive alone was calculated by subtracting the mass of the above - mentioned mesh alone. The mass at this time was set as M1.

[0220] Thereafter, the adhesive wrapped in the above-mentioned polyester mesh was immersed in ethyl acetate at room temperature (23°C) for 24 hours. Thereafter, the adhesive was taken out, air-dried for 24 hours in an environment at a temperature of 23°C and a relative humidity of 50%, and then dried in an oven at 80°C for 12 hours. After drying, its mass was weighed using a precision balance, and the mass of the above-mentioned mesh alone was subtracted therefrom, whereby the mass of the adhesive alone was calculated. The mass at this time was designated as M2. The gel fraction (%) is represented by (M2 / M1)×100. Thus, the gel fraction of the adhesive was derived. The results are shown in Table 2.

[0221] [Test Example 2] (Measurement of Dynamic Viscoelasticity)

[0222] The adhesive layers of the adhesive sheets manufactured in the laminated multilayer examples and comparative examples were laminated to produce a laminate with a thickness of 800 μm. Cylinders (height 800 μm) with a diameter of 8 mm were punched out from the obtained laminate of the adhesive layer and used as samples.

[0223] For the above-mentioned samples, in accordance with JIS K7244-6, using a viscoelasticity tester (manufactured by Anton Paar, product name “MCR302”), the storage modulus G’ and loss tangent tanδ were measured by the torsional shear method under the following conditions, and the storage modulus G’ (MPa) and loss tangent tanδ at 25°C, and the storage modulus G’ (MPa) and loss tangent tanδ at 80°C were obtained. The results are shown in Table 2.

[0224] Measurement frequency: 1 Hz

[0225] Heating rate: 5°C / min

[0226] Strain: 1%

[0227] Normal force: 1.0 N

[0228] Measurement temperature: -30°C to 140°C

[0229] [Test Example 3] (Tensile Test)

[0230] The adhesive layers of the adhesive sheets obtained in the laminated multilayer examples and comparative examples were cut out to obtain samples with a width of 10 mm and a length of 75 mm after the total thickness became 500 μm. The above-mentioned samples were set in a tensile testing machine (manufactured by Orientec, product name “TENSILON”) such that the sample measurement part was 10 mm wide and 25 mm long (elongation direction), and in an environment at 23°C and 50% RH, the tensile testing machine was used to elongate the sample at a tensile speed of 200 mm / minute. The above-mentioned sample was elongated until it broke, and the maximum stress (N / mm 2 ) and fracture energy (MJ / m3 )。In addition, the tensile elastic modulus (MPa) was measured by the above tensile test. The respective results are shown in Table 2.

[0231] [Test Example 4] (Measurement of the measurement gap)

[0232] For the adhesive layers of the pressure-sensitive adhesive sheets manufactured in the laminated multilayer examples and comparative examples, a laminate with a thickness of 800 μm was produced. A cylinder with a diameter of 8 mm (height 800 μm) was punched out from the obtained laminate of the adhesive layer and used as a sample.

[0233] The above sample was placed in a viscoelasticity tester (manufactured by Anton Paar, product name "MCR302"), and while applying a force of 1 N, the temperature was raised from -20°C to 100°C at a rate of 4°C / min. At this time, the measurement gap at 25°C and the measurement gap at 80°C were measured. In addition, the so-called measurement gap here refers to the distance between the measurement jig (an accessory of MCR301 manufactured by Anton Paar, PP08) and the Peltier module (an accessory of MCR301 manufactured by Anton Paar, P-PTD200). Then, the ratio of the measurement gap at 80°C to the measurement gap at 25°C (measurement gap at 80°C / measurement gap at 25°C) was calculated. The respective results are shown in Table 2.

[0234] [Test Example 5] (Measurement of the displacement amount)

[0235] The pressure-sensitive adhesive sheets manufactured in the examples and comparative examples were cut into 7 cm × 7 cm, and the release sheet R2 was peeled off and attached to a soda-lime glass plate with a thickness of 1.1 mm and a size of 7 cm × 7 cm. After that, the release sheet R1 was peeled off to expose the adhesive layer, and this was used as a sample.

[0236] The above sample was attached to a vertically erected soda-lime glass plate and left standing at 80°C for 240 hours. After that, the displacement amounts (mm) from the initial position at the left end and the right end of the sample were measured respectively, and the maximum value (mm) of the displacement amounts at the left end and the right end was obtained. Then, based on the maximum value of the displacement amount, the high-temperature adhesion was evaluated according to the following criteria. The results are shown in Table 2.

[0237] ◎: The maximum value of the displacement amount is less than 1 mm.

[0238] ○: The maximum value of the displacement amount is 1 mm or more and less than 4.5 mm.

[0239] △: The maximum value of the displacement amount is 4.5 mm or more and less than 7 mm.

[0240] ×: The maximum value of the displacement amount is 7 mm or more.

[0241] [Test Example 6] (Evaluation of Solvent Solubility)

[0242] The release sheet R2 was peeled off from the pressure-sensitive adhesive sheets obtained in the examples and comparative examples, and the exposed pressure-sensitive adhesive layer was attached to a soda-lime glass plate (thickness: 1.1 mm). Thereafter, the release sheet R1 was peeled off from this pressure-sensitive adhesive layer, and this was used as a sample. The obtained sample was taken out after being immersed in ethyl acetate for 72 hours, and with respect to the surface on the pressure-sensitive adhesive layer side in the soda-lime glass plate of this sample, it was visually observed and confirmed by finger whether there was a pressure-sensitive adhesive. Then, based on the following criteria, the solvent solubility of the pressure-sensitive adhesive layer was evaluated. The results are shown in Table 2.

[0243] ◎: No pressure-sensitive adhesive was visually observed to remain, and no tackiness was confirmed.

[0244] ○: No pressure-sensitive adhesive was visually observed to remain, but tackiness was confirmed.

[0245] ×: Pressure-sensitive adhesive was visually observed to remain.

[0246] [Table 1]

[0247]

[0248] [Table 2]

[0249]

[0250] As can be seen from Table 2, the pressure-sensitive adhesives and pressure-sensitive adhesive sheets of the examples are excellent in high-temperature bondability and also excellent in solvent solubility.

[0251] Industrial Applicability

[0252] The pressure-sensitive adhesives and pressure-sensitive adhesive sheets of the present invention are suitable for applications requiring high-temperature bondability and recyclability.

[0253] Explanation of Reference Numerals

[0254] 1A, 1B: Pressure-sensitive adhesive sheet; 11: Pressure-sensitive adhesive layer; 12, 12a, 12b: Release sheet; 13: Substrate.

Claims

1. An adhesive comprising a cyclodextrin compound, wherein the gel fraction of the adhesive is 30% or less, and the loss tangent tanδ thereof at 25 °C is 0.48 or more and 3.00 or less.

2. An adhesive comprising a cyclodextrin compound, wherein the gel fraction of the adhesive is 30% or less, And its maximum stress when formed into a thickness of 500 μm and a width of 10 mm, and elongated to the elongation at break at a measurement length of 20 mm and a tensile speed of 200 mm / minute in an environment of 23°C and 50% RH is 0.08 N / mm 2 or more.

3. The adhesive according to claim 1 or 2, characterized in that, and the loss tangent tanδ of the adhesive at 80 °C is 0.01 or more and 2.00 or less.

4. The adhesive according to claim 1 or 2, characterized in that The adhesive has a fracture energy of 0.80 MJ / m when formed into a thickness of 500 μm and a width of 10 mm, and elongated to the elongation at break at a measurement length of 20 mm and a tensile speed of 200 mm / minute in an environment of 23°C and 50% RH. 3 or more.

5. The adhesive according to claim 1 or 2, characterized in that, The adhesive is an acrylic adhesive.

6. The adhesive according to claim 1 or 2, characterized in that, The adhesive contains a polymer having a main chain formed by copolymerizing an acrylic monomer and a cyclodextrin compound having a polymerizable group.

7. The adhesive according to claim 1 or 2, characterized in that, The adhesive contains an acrylic polymer and a cyclodextrin compound formed by acylating all hydroxyl groups of cyclodextrin.

8. An adhesive sheet which is an adhesive sheet having at least an adhesive layer, characterized in that, The adhesive constituting the adhesive layer is the adhesive according to claim 1 or 2.

9. A method for producing an adhesive, which is a method for producing the adhesive according to claim 1 or 2, characterized in that the acrylic monomer and the cyclodextrin compound are completely cured at one time.

10. A method for manufacturing an adhesive, which is the method for manufacturing the adhesive according to claim 1 or 2, characterized in that, It comprises the following steps: a step of curing at least a cyclodextrin compound having a polymerizable group to obtain a primary cured product; a step of mixing an acrylic monomer, a cyclodextrin compound having a polymerizable group, and the primary cured product to obtain a secondary mixture; and a step of curing the secondary mixture to obtain a secondary cured product.

11. A method for manufacturing an adhesive, which is the method for manufacturing the adhesive according to claim 1 or 2, characterized in that, It comprises the following steps: a step of mixing an acrylic monomer and a cyclodextrin compound to obtain a primary mixture; a step of curing the primary mixture to obtain a primary cured product; a step of mixing an acrylic monomer, a cyclodextrin compound, and the primary cured product to obtain a secondary mixture; and a step of curing the secondary mixture to obtain a secondary cured product.

12. A method for manufacturing an adhesive, which is the method for manufacturing the adhesive according to claim 1 or 2, characterized in that, It comprises the following steps: a step of curing one or more acrylic monomers to obtain a primary cured product; a step of mixing at least a cyclodextrin compound and the primary cured product to obtain a secondary mixture; and a step of curing the secondary mixture to obtain a secondary cured product.

Images