Adhesive layer and adhesive sheet, and uses thereof

Abstract

To provide an adhesive layer and an adhesive sheet which have sufficient adhesiveness and exhibit superior moisture resistance and low-temperature flexibility.SOLUTION: An adhesive layer comprises an adhesive composition containing (A) a (meth)acrylic resin, (B) a graft-modified ethylene / α-olefin copolymer that satisfies the following conditions (b-1) and (b-2), and (C) a crosslinker, the adhesive layer having a gel fraction of 40 mass% or more. Condition (b-1): the graft-modified ethylene / α-olefin copolymer contains a main chain portion derived from an ethylene / α-olefin copolymer (B0). Condition (b-2): the graft-modified ethylene / α-olefin copolymer contains a graft portion derived from an ethylenically unsaturated monomer having a hydroxyl group.SELECTED DRAWING: None

Description

Technical Field

[0001] The present invention relates to an adhesive layer and an adhesive sheet having sufficient adhesiveness and excellent moisture resistance and low-temperature flexibility, and their uses.

Background Art

[0002] In recent years, electronic devices such as organic EL devices, solar cells, and sensor devices have been widely used for sealing, and input / output devices such as image display devices such as liquid crystal displays and touch panels used in combination with image display devices have become widely used. In the production of these, an adhesive composition and an adhesive sheet having an adhesive layer formed from the adhesive composition are often used.

[0003] The expansion of touch panels into automotive applications has also been increasing. In automotive applications, due to reasons such as high temperatures in summer, higher durability under high temperature and high humidity than in general applications is required. For example, Patent Document 1 discloses an adhesive composition containing a specific (meth)acrylic copolymer, an olefin polymer having a specific viscosity, and a crosslinking agent as an adhesive composition having excellent performance even under high temperature and high humidity conditions, and also discloses an adhesive sheet having an adhesive layer formed from such an adhesive composition.

[0004] In recent years, for electronic components constituting image display devices and input / output devices, a printed portion may be provided at the peripheral portion in order to impart design properties. When bonding such a printed surface with an adhesive sheet, flexibility to follow the step is required. For example, Patent Document 2 discloses an adhesive composition containing two types of methacrylic acid alkyl ester monomers having different carbon numbers of alkyl groups, a crosslinking agent, and a plasticizer as an adhesive composition having excellent flexibility performance.

Prior Art Documents

Patent Documents

[0005]

Patent Document 1

[0006] However, in the pressure-sensitive adhesive sheet using a conventional pressure-sensitive adhesive composition, there is room for improvement from the viewpoints of flexibility in a low-temperature environment and compatibility between adhesive strength and moisture resistance. For example, a pressure-sensitive adhesive sheet using a pressure-sensitive adhesive composition containing a (meth)acrylic copolymer, an unmodified olefin polymer, and a crosslinking agent tends to have insufficient moisture resistance, and there is room for improvement from the viewpoint of compatibility between adhesive strength and moisture resistance.

[0007] An object of the present invention is to provide a pressure-sensitive adhesive layer and a pressure-sensitive adhesive sheet having sufficient adhesiveness and excellent moisture resistance and low-temperature flexibility. [Means for Solving the Problems]

[0008] As a result of intensive studies to solve the above problems, the present inventors have found that in a pressure-sensitive adhesive composition containing a (meth)acrylic copolymer, an olefin polymer, and a crosslinking agent, the above problems can be solved by adopting a specific graft-modified olefin polymer as the olefin polymer, and thus the present invention has been completed.

[0009] The present invention provides the following. [1] A pressure-sensitive adhesive composition comprising a (meth)acrylic resin (A), a graft-modified ethylene-α-olefin copolymer (B) satisfying the following (b-1) to (b-2), and a crosslinking agent (C), and A pressure-sensitive adhesive layer having a gel fraction of 40% by mass or more; (b-1) including a main chain portion derived from an ethylene-α-olefin copolymer (B0); (b-2) including a graft portion derived from an ethylenically unsaturated monomer having a hydroxyl group. [2] The graft-modified ethylene·α-olefin copolymer (B) further satisfies the following (b-3) to (b-6), when the total content of the (meth)acrylic resin (A), the graft-modified ethylene·α-olefin copolymer (B), and the crosslinking agent (C) is 100% by mass, the amount of the (meth)acrylic resin (A) is 47% by mass or more and 99% by mass, the amount of the graft-modified ethylene·α-olefin copolymer (B) is 0.5% by mass or more and 50% by mass or less, and the amount of the crosslinking agent (C) is 0.5% by mass or more and 5% by mass or less; the pressure-sensitive adhesive layer according to [1]; (b-3) The proportion of the graft part is 0.1% by mass or more and less than 70% by mass (however, the total amount of the main chain part and the graft part is 100% by mass.); (b-4) The weight average molecular weight (Mw) determined by gel permeation chromatography (GPC) is 1,500 to 30,000; (b-5) The kinematic viscosity at 100 °C is 10 to 5,000 mm 2 / s; (b-6) No melting point is observed as measured by differential scanning calorimetry (DSC). [3] The pressure-sensitive adhesive layer according to [1] or [2], having a haze of 5.0% or less as measured in accordance with JIS K7136. [4] The pressure-sensitive adhesive layer according to any one of [1] to [3], having a total light transmittance of 80% or more as measured in accordance with JIS K7361 of any one of the above. [5] The pressure-sensitive adhesive layer according to any one of [1] to [4], having a thickness of 5 to 200 μm. [6] A pressure-sensitive adhesive sheet having the pressure-sensitive adhesive layer according to any one of [1] to [5].[[]END]] [7] A laminate having the pressure-sensitive adhesive sheet according to [6].[[]END]] [8] An optical member having the pressure-sensitive adhesive sheet according to [6].[[]END]] [9] A touch panel type input / output device or an image display device having the pressure-sensitive adhesive sheet described in [6].

[10] A method for producing a pressure-sensitive adhesive sheet including a pressure-sensitive adhesive layer, (meth)acrylic resin (A), A graft-modified ethylene·α-olefin copolymer (B) produced by the following method (α) or method (β) and satisfying the following requirements (b-1) to (b-2), Crosslinking agent (C) Mixing to obtain a composition containing the (meth)acrylic resin (A), the graft-modified ethylene·α-olefin copolymer (B), and the crosslinking agent (C) (step (S1)); Forming a pressure-sensitive adhesive layer from the composition obtained in the step (S1) (step (S2)) A method for producing a pressure-sensitive adhesive sheet including; (b-1) including a main chain portion derived from an ethylene·α-olefin copolymer; (b-2) including a graft portion derived from an ethylenically unsaturated monomer having a hydroxyl group; Method (α): In the presence of a catalyst system including at least one compound (Q) selected from the group consisting of a crosslinking metallocene compound (P) represented by the following (Formula 1), an organometallic compound (Q-1), an organoaluminum oxy compound (Q-2), and a compound (Q-3) that reacts with the crosslinking metallocene compound (P) to form an ion pair, solution-polymerizing ethylene and an α-olefin to obtain an ethylene·α-olefin copolymer (B0) (step (SB1)); Adding the ethylenically unsaturated monomer having a hydroxyl group to the ethylene·α-olefin copolymer (B0) and subjecting it to graft copolymerization (step (SB2)) A method including

[0010] [Chemical formula] [In (Formula 1), R 1 , R 2 , R 3 , R 4 , R 5 , R 8, R 9 and R 12 are each independently a hydrogen atom, a hydrocarbon group or a silicon-containing hydrocarbon group, and a plurality of adjacent groups may be linked to each other to form a ring structure, R 6 and R 11 are the same group as each other and are a hydrogen atom, a hydrocarbon group or a silicon-containing hydrocarbon group, R 7 and R 10 are the same group as each other and are a hydrogen atom, a hydrocarbon group or a silicon-containing hydrocarbon group, R 6 and R 7 may be bonded to a hydrocarbon having 2 to 3 carbon atoms to form a ring structure, R 10 and R 11 may be bonded to a hydrocarbon having 2 to 3 carbon atoms to form a ring structure, R 6 R 7 R 10 and R 11 are not hydrogen atoms simultaneously, R 13 and R 14 are each independently a hydrogen atom, a hydrocarbon group or a silicon-containing hydrocarbon group, and may be linked to each other to form a ring structure, Y is a carbon atom or a silicon atom, M is Ti, Zr or Hf, Q is independently a halogen atom, a hydrocarbon group, an anionic ligand or a neutral ligand capable of coordinating to a lone pair of electrons, j is an integer from 1 to 4.]. Method (β): A step (SB1') of solution-polymerizing ethylene and an α-olefin in the presence of a vanadium-based catalyst composed of a soluble vanadium compound (V) and an organoaluminum compound (Q') to obtain an ethylene·α-olefin copolymer (B0), A step (SB2) of adding the ethylenically unsaturated monomer having a hydroxyl group to the ethylene·α-olefin copolymer (B0) and subjecting it to graft copolymerization, and a method comprising the above steps.

[11] The substituent R of the crosslinked metallocene compound (P) represented by the above (Formula 1) 13 and R 14 The production method according to

[10] , wherein either one or both of them are aryl groups.

[12] The substituent R of the crosslinked metallocene compound (P) represented by the above (Formula 1) 13 and R 14 are both aryl groups, and either one of the substituents R 2 and R 3 is a saturated hydrocarbon group having 4 carbon atoms. The production method according to

[10] . [Advantages of the Invention]

[0011] According to the present invention, an adhesive layer and an adhesive sheet having sufficient adhesiveness and excellent moisture resistance and low temperature flexibility can be provided. [Modes for Carrying Out the Invention]

[0012] Hereinafter, the present invention will be described in more detail. Here, in this specification, "~" indicating a numerical range means a numerical range including the lower limit value and the upper limit value unless otherwise specified. For example, when expressed as "M~N" (where M and N are numerical values satisfying M < N), it means "M or more and N or less" unless otherwise specified. Adhesive composition The pressure-sensitive adhesive composition used in the present invention contains (meth)acrylic resin (A), a graft-modified ethylene / α-olefin copolymer (B) satisfying specific requirements, a crosslinking agent (C), and.

[0013] In this specification, "(meth)acrylic" means acrylic or methacrylic, "(meth)acrylate" means acrylate or methacrylate, and "(co)polymer" means a homopolymer or a copolymer.

[0014] [(Meth)acrylic resin (A)] (Meth)acrylic resin (A) is a (co)polymer of an acrylic monomer or a methacrylic monomer. The acrylic monomer or methacrylic monomer constituting (meth)acrylic resin (A) may be, for example, a monomer derived from fossil fuel or a monomer derived from biomass.

[0015] The acrylic monomer or methacrylic monomer constituting (meth)acrylic resin (A) may be a single species or a combination of two or more species. Here, (meth)acrylic resin (A) preferably satisfies the following requirements (a-1) and (a-2).

[0016] Requirement (a-1) (Meth)acrylic resin (A) preferably contains a structural unit derived from a (meth)acrylate having an alkyl group with 1 to 12 carbon atoms and a structural unit derived from a (meth)acrylate containing a hydroxyl group.

[0017] Specifically, when (meth)acrylic resin (A) contains a structural unit derived from a (meth)acrylate having an alkyl group with a small number of carbon atoms, for example, a structural unit derived from a (meth)acrylate having an alkyl group with 1 to 12 carbon atoms, the glass transition temperature (Tg) of (meth)acrylic resin (A) increases, and the adhesiveness of the adhesive composition further increases. Here, the "structural unit derived from a (meth)acrylate having an alkyl group with 1 to 12 carbon atoms" refers to a structural unit corresponding to a (meth)acrylate having an alkyl group with 1 to 12 carbon atoms. Specifically, -[-CH2-CR'(-C(=O)-OR)-]- ···[A1] (R is an alkyl group having 1 to 12 carbon atoms, and R' is a hydrogen atom or a methyl group.) It is a structural unit represented by.

[0018] From the above viewpoints, the (meth)acrylate having an alkyl group with 1 to 12 carbon atoms is more preferably a (meth)acrylate having an alkyl group with 1 to 10 carbon atoms, and even more preferably a (meth)acrylate having an alkyl group with 2 to 8 carbon atoms. The alkyl group may be linear or branched.

[0019] Examples of the (meth)acrylate having an alkyl group with 1 to 12 carbon atoms include methyl (meth)acrylate, ethyl (meth)acrylate, n-propyl (meth)acrylate, isopropyl (meth)acrylate, n-butyl (meth)acrylate, isobutyl (meth)acrylate, pentyl (meth)acrylate, hexyl (meth)acrylate, heptyl (meth)acrylate, octyl (meth)acrylate, isooctyl (meth)acrylate, 2-ethylhexyl (meth)acrylate, decyl (meth)acrylate, lauryl (meth)acrylate, and the like.

[0020] In the (meth)acrylic resin (A), the content of the structural unit derived from the (meth)acrylate having an alkyl group with 1 to 12 carbon atoms with respect to the total amount of its structural units is preferably 50 mol% or more, more preferably 55 mol% or more, and even more preferably 60 mol% or more. The content is preferably 99 mol% or less, more preferably 95 mol% or less, and even more preferably 90 mol% or less.

[0021] In addition, when the (meth)acrylic resin (A) contains a structural unit derived from a (meth)acrylate containing a hydroxyl group, the number of crosslinking points by the crosslinking agent (C) increases, so that the crosslinking density of the pressure-sensitive adhesive composition increases and it is easy to increase the molecular weight. Such a pressure-sensitive adhesive composition is excellent in the mechanical strength of the pressure-sensitive adhesive layer and is less likely to cause a decrease in adhesiveness. Here, the "structural unit derived from a (meth)acrylate containing a hydroxyl group" means a structural unit corresponding to a (meth)acrylate containing a hydroxyl group.

[0022] Examples of the (meth)acrylate containing the hydroxyl group include hydroxyalkyl (meth)acrylates such as hydroxyethyl (meth)acrylate and hydroxypropyl (meth)acrylate, and hydroxyalkyl (meth)acrylamides such as N-methylol (meth)acrylamide. Among these, from the above viewpoints, the (meth)acrylate containing the hydroxyl group is preferably hydroxyethyl (meth)acrylate.

[0023] That is, examples of the "structural unit derived from the (meth)acrylate containing a hydroxyl group" include a structural unit derived from hydroxyalkyl (meth)acrylate and a structural unit derived from hydroxyalkyl (meth)acrylamide. Specifically, -[-CH2-CR'(-C(=O)-O-R-OH)-]- ···[A2a] (R is an alkanediyl group, preferably an ethane-1,2-diyl group or a propane-1,3-diyl group, more preferably an ethane-1,2-diyl group. R' is a hydrogen atom or a methyl group.) The structural unit represented by, and -[-CH2-CR'(-C(=O)-NH-R-OH)-]- ···[A2b] (R is an alkanediyl group (for example, a methanediyl group). R' is a hydrogen atom or a methyl group.) The structural unit represented by can be mentioned. In one of the exemplary and preferred embodiments of the present invention, the "structural unit derived from the (meth)acrylate containing a hydroxyl group" is the structural unit represented by the above formula [A2a].

[0024] (Meth)acrylic resin (A) preferably has a content of the structural unit derived from the (meth)acrylate containing the hydroxyl group of 0.1 mol% or more, more preferably 0.2 mol% or more, still more preferably 0.3 mol% or more, based on the total amount of its structural units. Further, the content is preferably 10 mol% or less, more preferably 5 mol% or less, still more preferably 3 mol% or less.

[0025] Further, the (meth)acrylic resin (A) may be a copolymer having a structural unit derived from a monomer (or oligomer) having a functional group capable of forming a crosslink, which is different from the (meth)acrylate having an alkyl group with 1 to 12 carbon atoms or the (meth)acrylate containing a hydroxyl group described above. Examples of the monomer having a functional group capable of forming a crosslink include (meth)acrylic acid and (meth)acrylamide.

[0026] Further, the (meth)acrylic resin (A) may be a copolymer having a structural unit derived from a vinyl monomer other than those described above, if necessary. Examples of such vinyl monomers include styrene and vinyl acetate.

[0027] Note that the content of each structural unit in the (meth)acrylic resin (A) can be determined using an appropriate method. For example, as shown in the following examples, it can be determined using pyrolysis gas chromatography-mass spectrometry (pyrolysis GC-MS).

[0028] Requirement (a-2) The (meth)acrylic resin (A) preferably has a peak temperature of loss tangent (tanδ) due to the glass transition temperature as measured by the temperature dependence measurement of dynamic viscoelasticity (frequency 1 Hz, -100 to 200 °C) of less than 0 °C.

[0029] Specifically, when the peak temperature of loss tangent (tanδ) due to the glass transition temperature of the (meth)acrylic resin (A) as measured by the temperature dependence measurement of dynamic viscoelasticity (frequency 1 Hz, -100 to 200 °C) is within a specific range, for example, less than 0 °C, the pressure-sensitive adhesive composition in the form of a thin film adhesive layer can exhibit adhesiveness over a wide temperature range.

[0030] From the above viewpoints, the (meth)acrylic resin (A) preferably has a peak temperature of loss tangent (tanδ) of more preferably -80 °C or higher, still more preferably -70 °C or higher. Also, the peak temperature is more preferably less than 0 °C, still more preferably -5 °C or lower. (Meta) The peak temperature of the loss tangent (tanδ) of the acrylic resin (A) can be adjusted to the above range by changing the monomers to be polymerized and their ratios.

[0031] Production method of (meth)acrylic resin (A) (Meta) The acrylic resin (A) can be synthesized by a known polymerization method using the monomers (or oligomers) that are the materials for the above structural units. The above polymerization method is not particularly limited as long as it is a radical polymerization method including bulk polymerization, solution polymerization, suspension polymerization, etc. Among these, the solution polymerization method is preferable because it is easy to control the glass transition temperature (Tg) and other properties of the (meta)acrylic resin (A), and it is easy to synthesize the (meta)acrylic resin (A) having desired properties.

[0032] A polymerization initiator may be used during polymerization. Examples of the above polymerization initiator include dicumyl peroxide, benzoyl peroxide, tert-butyl peroxy-2-ethylhexanoate, 1,1-bis(tert-butylperoxy)cyclohexane, α,α'-azobisisobutyronitrile, acetyl peroxide, tert-butyl peroxypivalate, tert-butyl hydroperoxide, cumene hydroperoxide, tert-hexyl peroxypivalate, 2,2'-azobis-(2,4-dimethylvaleronitrile), lauroyl peroxide, tert-butyl peroxyneohexanoate, di-tert-butyl peroxide, azodicyclohexylcarbonitrile, dimethyl α,α-azodiisobutyrate, succinic peroxide, dicumene peroxide, and dichlorobenzoyl peroxide. Examples of the solvent used in the above solution polymerization include ethyl acetate, butyl acetate, benzene, toluene, xylene, cyclohexane, and methyl ethyl ketone.

[0033] [Graft-modified ethylene·α-olefin copolymer (B)] The graft-modified ethylene·α-olefin copolymer (B) satisfies the following requirements (b-1) to (b-2).

[0034] (b-1) It contains a main chain portion derived from an ethylene-α-olefin copolymer (B0). (b-2) It contains a graft portion derived from an ethylenically unsaturated monomer having a hydroxyl group.

[0035] Here, in addition to the above requirements (b-1) to (b-2), the graft-modified ethylene-α-olefin copolymer (B) preferably satisfies one or more of the following requirements (b-3) to (b-6), more preferably satisfies two or more, and even more preferably satisfies all. Further, the graft-modified ethylene-α-olefin copolymer (B) may further satisfy the following requirement (b-7).

[0036] Requirement (b-1) The graft-modified ethylene-α-olefin copolymer (B) contains a main chain portion derived from the ethylene-α-olefin copolymer (B0). Here, the "main chain portion derived from the ethylene-α-olefin copolymer (B0)" refers to the main chain portion corresponding to the ethylene-α-olefin copolymer (B0). This ethylene-α-olefin copolymer (B0) gives the graft-modified ethylene-α-olefin copolymer (B) by introducing a "graft portion derived from an ethylenically unsaturated monomer having a hydroxyl group" described later by graft modification.

[0037] Examples of the α-olefin that constitutes the ethylene·α-olefin copolymer (B0) include α-olefins other than ethylene. Typical examples include linear α-olefins having 3 to 20 carbon atoms such as propylene, 1-butene, 1-pentene, 1-hexene, 1-heptene, 1-octene, 1-nonene, 1-decene, 1-undecene, 1-dodecene, 1-tridecene, 1-tetradecene, 1-pentadecene, 1-hexadecene, 1-heptadecene, 1-octadecene, 1-nonadecene, 1-eicosene, and α-olefins having a branch with 3 to 20 carbon atoms such as 3-methyl-1-pentene, 4-methyl-1-pentene, 8-methyl-1-nonene, 7-methyl-1-decene, 6-methyl-1-undecene, 6,8-dimethyl-1-decene. In the ethylene·α-olefin copolymer (B0), these α-olefins may be contained alone or in combination of two or more. Among these α-olefins, in terms of effectively reducing crystallinity to become liquid, improving fluidity and flexibility, and improving the compatibility between the ethylene·α-olefin copolymer and the (meth)acrylic resin (A), α-olefins having 3 to 10 carbon atoms are preferred, and propylene is particularly preferred. Here, the ethylene·α-olefin copolymer (B0) preferably satisfies the following (b-1-1) to (b-1-5).

[0038] Requirement (b-1-1) From the viewpoint of reducing bleed-out, the ethylene·α-olefin copolymer (B0) used in the present invention preferably has a weight average molecular weight (Mw) of 1,500 to 30,000 in terms of polystyrene as determined by gel permeation chromatography (GPC), and more preferably has a weight average molecular weight (Mw) of 1,500 to 15,000. In one particularly preferred embodiment of the present invention, the weight average molecular weight (Mw) is 1,500 to 8,500. However, the weight average molecular weight (Mw) may exceed 8,500, for example, it may be about 14,000 (for example, 13,000 to 15,000).

[0039] When the weight-average molecular weight (Mw) is below the above lower limit, especially less than 1,500, it may cause bleed-out because it contains low-molecular-weight components. On the other hand, when the weight-average molecular weight (Mw) exceeds the above upper limit, especially exceeds 30,000, the compatibility with the (meth)acrylic resin (A) decreases, which may cause bleed-out.

[0040] Requirement (b-1-2) From the viewpoint of reducing bleed-out, the ethylene·α-olefin copolymer (B0) used in the present invention preferably has a molecular weight distribution (Mw / Mn) of 2.5 or less, more preferably 2.2 or less, and even more preferably 2.1 or less, as determined by gel permeation chromatography (GPC). When the molecular weight distribution (Mw / Mn) exceeds the above upper limit, especially exceeds 2.5, it may cause bleed-out due to low-molecular-weight components and high-molecular-weight components with low compatibility.

[0041] Requirement (b-1-3) From the viewpoint of reducing bleed-out, the ethylene·α-olefin copolymer (B0) used in the present invention preferably has a kinematic viscosity at 100°C of 10 to 5,000 mm 2 / s, more preferably 15 to 3,500 mm 2 / s, and even more preferably 20 to 2,500 mm 2 / s.

[0042] When the kinematic viscosity at 100°C is below the above lower limit, especially less than 10 mm 2 / s, it may cause bleed-out because it contains high-flow components. When the kinematic viscosity at 100°C exceeds the above upper limit, especially exceeds 5,000 mm 2 / s, the dispersibility in the (meth)acrylic resin (A) decreases due to high-viscosity components, which may cause bleed-out.

[0043] Requirement (b-1-4) The ethylene-α-olefin copolymer (B0) used in the present invention preferably has an ethylene unit content of 10 to 85 mol%, more preferably 30 to 70 mol%, and even more preferably 40 to 60 mol%.

[0044] When the content of ethylene units is greater than the above upper limit or less than the above lower limit, particularly when it is less than 10 mol% or greater than 85 mol%, the crystallinity increases, the compatibility with the (meth)acrylic resin (A) deteriorates, and bleeding out or a decrease in mechanical properties may occur.

[0045] Requirement (b-1-5) The ethylene-α-olefin copolymer (B0) used in the present invention preferably has no melting point observed by differential scanning calorimetry (DSC). Here, the non-observation of the melting point (Tm) means that the heat of fusion (ΔH) (unit: J / g) measured by differential scanning calorimetry (DSC) is not substantially measured. The non-measurement of the heat of fusion (ΔH) means that no peak is observed in the differential scanning calorimeter (DSC) measurement or the observed heat of fusion is 1 J / g or less.

[0046] The non-observation of the melting point is preferable because it has the effect of improving fluidity, improves the compatibility between the graft-modified ethylene-α-olefin copolymer (B) obtained from the ethylene-α-olefin copolymer (B0) and the (meth)acrylic resin (A), and can provide a flexibility-imparting effect at low temperatures.

[0047] Production method of ethylene·α-olefin copolymer (B0) The ethylene-α-olefin copolymer (B0) can be produced using known methods without limitation.

[0048] For example, there is a method of copolymerizing ethylene and an α-olefin in the presence of a catalyst composed of a transition metal compound such as vanadium, zirconium, titanium, hafnium, etc., an organoaluminum compound (organoaluminum oxy compound) and / or an ionizing ionic compound. A metallocene catalyst using a transition metal compound such as zirconium, titanium, hafnium, etc. is preferable because the amount of 2,1-bonding (inversion) of two or more consecutive propylene monomers is reduced, and the low-temperature properties of the adhesive composition are improved. Such methods are described, for example, in WO 2000 / 34420 pamphlet, JP-A-62-121710, WO 2004 / 29062 pamphlet, JP-A-2004-175707, WO 2001 / 27124 pamphlet, etc.

[0049] The ethylene and α-olefin, which are monomers constituting the ethylene·α-olefin copolymer (B0), may be, for example, monomers derived from fossil fuels or monomers derived from biomass, and these monomers may be used alone or in combination of two or more. In other words, the ethylene·α-olefin copolymer may be composed only of monomers derived from fossil fuels, may be composed only of monomers derived from biomass, or may use monomers derived from fossil fuels and monomers derived from biomass in combination.

[0050] Fossil fuels are petroleum, coal, natural gas, shale gas or a combination thereof. Biomass is any renewable natural raw material and its residue, such as plant-derived or animal-derived, including fungi, yeast, algae and bacteria.

[0051] The ethylene-α-olefin copolymer (B0) can be produced by copolymerizing ethylene and an α-olefin (for example, an α-olefin having 3 to 20 carbon atoms) in the presence of a metallocene catalyst containing at least one compound (Q) selected from the group consisting of a crosslinked metallocene compound (P) represented by the following (Formula 1), an organometallic compound (Q-1), an organoaluminum oxy compound (Q-2), and a compound (Q-3) that reacts with the crosslinked metallocene compound (P) to form an ionic pair. Further, the ethylene-α-olefin copolymer (B0) can also be produced by copolymerizing ethylene and an α-olefin (for example, an α-olefin having 3 to 20 carbon atoms) in the presence of a vanadium catalyst composed of a soluble vanadium compound (V) and an organoaluminum compound (Q').

[0052] [Metallocene catalyst] In the present invention, a metallocene catalyst can be used as the olefin polymerization catalyst for obtaining the ethylene-α-olefin copolymer (B0). The metallocene catalyst that can be used in the production of the ethylene-α-olefin copolymer (B0) contains a crosslinked metallocene compound (P) represented by the following (Formula 1), and at least one compound (Q) selected from the group consisting of an organometallic compound (Q-1), an organoaluminum oxy compound (Q-2), and a compound (Q-3) that reacts with the crosslinked metallocene compound (P) to form an ionic pair.

[0053] [Crosslinked metallocene compound (P)] The crosslinked metallocene compound (P) constituting the metallocene catalyst that can be used in the present invention has a structure represented by the following (Formula 1).

[0054] [Chemical formula] Y, M, R in (Formula 1) 1 ~R 14 、Q and j will be described below.

[0055] 《Y》 Y is a carbon atom or a silicon atom, preferably a carbon atom.

[0056] 《M》 M is a titanium atom, a zirconium atom or a hafnium atom (Ti, Zr or Hf), preferably a zirconium atom (Zr).

[0057] 《R 1 ~R 14 》 R 1 、R 2 、R 3 、R 4 、R 5 、R 8 、R 9 and R 12 are each independently an atom or a substituent selected from the group consisting of a hydrogen atom, a hydrocarbon group and a silicon-containing hydrocarbon group, and a plurality of adjacent groups may be linked to each other to form a ring structure.

[0058] Examples of the hydrocarbon group include an alkyl group having 1 to 20 carbon atoms, a cyclic saturated hydrocarbon group having 3 to 20 carbon atoms, a chain unsaturated hydrocarbon group having 2 to 20 carbon atoms, a cyclic unsaturated hydrocarbon group having 3 to 20 carbon atoms, an alkylene group having 1 to 20 carbon atoms, an arylene group having 6 to 20 carbon atoms, and the like.

[0059] Examples of the alkyl group having 1 to 20 carbon atoms include linear saturated hydrocarbon groups such as methyl group, ethyl group, n-propyl group, allyl group, n-butyl group, n-pentyl group, n-hexyl group, n-heptyl group, n-octyl group, n-nonyl group, n-decanyl group, etc., and branched saturated hydrocarbon groups such as isopropyl group, isobutyl group, sec-butyl group, tert-butyl group, tert-amyl group, neopentyl group, 3-methylpentyl group, 1,1-diethylpropyl group, 1,1-dimethylbutyl group, 1-methyl-1-propylbutyl group, 1,1-dipropylbutyl group, 1,1-dimethyl-2-methylpropyl group, 1-methyl-1-isopropyl-2-methylpropyl group, cyclopropylmethyl group, etc. The number of carbon atoms of the alkyl group is preferably 1 to 6.

[0060] Examples of the cyclic saturated hydrocarbon group having 3 to 20 carbon atoms include cyclic saturated hydrocarbon groups such as cyclopropyl group, cyclobutyl group, cyclopentyl group, cyclohexyl group, cycloheptyl group, cyclooctyl group, norbornyl group, 1-adamantyl group, 2-adamantyl group, etc., and groups in which a hydrogen atom of the cyclic saturated hydrocarbon group is replaced with a hydrocarbon group having 1 to 17 carbon atoms such as 3-methylcyclopentyl group, 3-methylcyclohexyl group, 4-methylcyclohexyl group, 4-cyclohexylcyclohexyl group, 4-phenylcyclohexyl group, etc. The number of carbon atoms of the cyclic saturated hydrocarbon group is preferably 5 to 11.

[0061] Examples of the chain unsaturated hydrocarbon group having 2 to 20 carbon atoms include alkenyl groups such as ethenyl group (vinyl group), 1-propenyl group, 2-propenyl group (allyl group), 1-methylethenyl group (isopropenyl group), etc., and alkynyl groups such as ethynyl group, 1-propynyl group, 2-propynyl group (propargyl group), etc. The number of carbon atoms of the chain unsaturated hydrocarbon group is preferably 2 to 4.

[0062] Examples of the cyclic unsaturated hydrocarbon group having 3 to 20 carbon atoms include a cyclopentadienyl group, a norbornenyl group, a phenyl group, a naphthyl group, an indenyl group, an azulenyl group, a phenanthryl group, an anthracenyl group, etc., which are cyclic unsaturated hydrocarbon groups, and groups in which a hydrogen atom of the cyclic unsaturated hydrocarbon group is replaced with a hydrocarbon group having 1 to 15 carbon atoms, such as a 3-methylphenyl group (m-tolyl group), a 4-methylphenyl group (p-tolyl group), a 4-ethylphenyl group, a 4-tert-butylphenyl group, a 4-cyclohexylphenyl group, a biphenylyl group, a 3,4-dimethylphenyl group, a 3,5-dimethylphenyl group, a 2,4,6-trimethylphenyl group (mesityl group), etc., and groups in which a hydrogen atom of a linear hydrocarbon group or a branched saturated hydrocarbon group is replaced with a cyclic saturated hydrocarbon group or a cyclic unsaturated hydrocarbon group having 3 to 19 carbon atoms, such as a benzyl group, a cumyl group, etc. The number of carbon atoms of the cyclic unsaturated hydrocarbon group is preferably 6 to 10.

[0063] Examples of the alkylene group having 1 to 20 carbon atoms include a methylene group, an ethylene group, a dimethylmethylene group (isopropylidene group), an ethylmethylene group, a methylethylene group, an n-propylene group, etc. The number of carbon atoms of the alkylene group is preferably 1 to 6.

[0064] Examples of the arylene group having 6 to 20 carbon atoms include an o-phenylene group, an m-phenylene group, a p-phenylene group, a 4,4'-biphenylylene group, etc. The number of carbon atoms of the arylene group is preferably 6 to 12.

[0065] Examples of the silicon-containing hydrocarbon group include alkylsilyl groups such as a trimethylsilyl group, a triethylsilyl group, a tert-butyldimethylsilyl group, a triisopropylsilyl group, etc., arylsilyl groups such as a dimethylphenylsilyl group, a methyldiphenylsilyl group, a tert-butyldiphenylsilyl group, etc., in which a carbon atom is replaced with a silicon atom in the above-described hydrocarbon group, and pentamethyldisilanilyl group, a trimethylsilylmethyl group, etc. The number of carbon atoms of the alkylsilyl group is preferably 1 to 10, and the number of carbon atoms of the arylsilyl group is preferably 6 to 18.

[0066] In the present invention, R 2 and R 3 It is preferable that either one of them is a saturated hydrocarbon group having 4 carbon atoms. In this case, all of R 1 to R 4 other than the saturated hydrocarbon group having 4 carbon atoms may be hydrogen atoms, or, of R 1 to R 4 the two groups adjacent to the saturated hydrocarbon group having 4 carbon atoms may be hydrogen atoms and the non-adjacent groups may be methyl groups. However, this does not prevent the case where neither R 2 nor R 3 is a saturated hydrocarbon group having 4 carbon atoms. For example, all of R 1 to R 4 may be hydrogen atoms.

[0067] R 6 and R 11 are the same group as each other and are a hydrogen atom, a hydrocarbon group or a silicon-containing hydrocarbon group, and the details of the hydrocarbon group and the silicon-containing hydrocarbon group are as described above. R 7 and R 10 are the same group as each other and are a hydrogen atom, a hydrocarbon group or a silicon-containing hydrocarbon group, and the details of the hydrocarbon group and the silicon-containing hydrocarbon group are as described above.

[0068] R 6 and R 7 may be bonded to a hydrocarbon having 2 to 3 carbon atoms to form a ring structure, and R 10 and R 11 may be bonded to a hydrocarbon having 2 to 3 carbon atoms to form a ring structure. R 6 , R 7 , R 10 and R 11 are not hydrogen atoms at the same time.

[0069] R 13 and R 14Each is independently a hydrogen atom, a hydrocarbon group or a silicon-containing hydrocarbon group, and may be linked to each other to form a ring structure. Details of the hydrocarbon group and the silicon-containing hydrocarbon group are as described above, and examples of the hydrocarbon group further include an aryl group and a substituted aryl group.

[0070] Examples of the aryl group partly overlap with the examples of the cyclic unsaturated hydrocarbon group having 3 to 20 carbon atoms described above, and include a phenyl group, a 1-naphthyl group, a 2-naphthyl group, an anthracenyl group, a phenanthrenyl group, a tetracenyl group, a chrysenyl group, a pyrenyl group, an indenyl group, an azulenyl group, a pyrrolyl group, a pyridyl group, a furanyl group, a thiophenyl group, etc., which are substituents derived from aromatic compounds. As the aryl group, a phenyl group or a 2-naphthyl group is preferable.

[0071] Examples of the aromatic compound include benzene, naphthalene, anthracene, phenanthrene, tetracene, chrysene, pyrene, indene, azulene, pyrrole, pyridine, furan, thiophene, etc., which are aromatic hydrocarbons and heteroaromatic compounds.

[0072] The replacement aryl group partially overlaps with the examples of the cyclic unsaturated hydrocarbon group having 3 to 20 carbon atoms described above, and at least one hydrogen atom of the aryl group is replaced by at least one substituent selected from the group consisting of a hydrocarbon group having 1 to 20 carbon atoms, an aryl group, a silicon-containing group, a nitrogen-containing group, an oxygen-containing group, a halogen atom, and a halogen-containing group. Specific examples include 3-methylphenyl group (m-tolyl group), 4-methylphenyl group (p-tolyl group), 3-ethylphenyl group, 4-ethylphenyl group, 3,4-dimethylphenyl group, 3,5-dimethylphenyl group, biphenylyl group, 4-(trimethylsilyl)phenyl group, 4-aminophenyl group, 4-(dimethylamino)phenyl group, 4-(diethylamino)phenyl group, 4-morpholinylphenyl group, 4-methoxyphenyl group, 4-ethoxyphenyl group, 4-phenoxyphenyl group, 3,4-dimethoxyphenyl group, 3,5-dimethoxyphenyl group, 3-methyl-4-methoxyphenyl group, 3,5-dimethyl-4-methoxyphenyl group, 3-(trifluoromethyl)phenyl group, 4-(trifluoromethyl)phenyl group, 3-chlorophenyl group, 4-chlorophenyl group, 3-fluorophenyl group, 4-fluorophenyl group, 5-methylnaphthyl group, 2-(6-methyl)pyridyl group, and the like.

[0073] In the present invention, it is preferable that either one or both of R 13 and R 14 are aryl groups. In one of the preferred embodiments of the present invention, both R 13 and R 14 are aryl groups. However, this does not prevent one of R 13 and R 14 from being a group other than an aryl group. For example, R 13 may be an aryl group and R 14 may be an alkyl group having 1 to 20 carbon atoms.

[0074] 《Q》 Q is selected from a halogen atom, a hydrocarbon group, an anionic ligand, and a neutral ligand capable of coordinating with a lone pair of electrons in the same or different combinations.

[0075] Examples of the halogen atom include a fluorine atom, a chlorine atom, a bromine atom, and an iodine atom, and a chlorine atom is preferred. Examples of the hydrocarbon group include hydrocarbon groups having 1 to 20 carbon atoms. Details of the hydrocarbon group are as described above, and the number of carbon atoms of the hydrocarbon group is preferably 1 to 7.

[0076] Examples of the anionic ligand can include alkoxy groups such as a methoxy group, a tert-butoxy group, and a phenoxy group, carboxylate groups such as acetate and benzoate, and sulfonate groups such as mesylate and tosylate.

[0077] Examples of the neutral ligand capable of coordinating with an unshared electron pair can include organic phosphorus compounds such as trimethylphosphine, triethylphosphine, triphenylphosphine, and diphenylmethylphosphine, and ether compounds such as tetrahydrofuran, diethyl ether, dioxane, and 1,2-dimethoxyethane.

[0078] 《j》 j is an integer of 1 to 4, and preferably 2.

[0079] (Examples of crosslinked metallocene compound (P)) Examples of the bridged metallocene compound (P) include a bridged metallocene compound (P1) in which in the above (Formula 1), either one or both of R 13 and R 14 are an aryl group.

[0080] Preferable examples of the bridged metallocene compound (P1) include a bridged metallocene compound (P2) in which in the above (Formula 1), both of R 13 and R 14 are an aryl group, and either one of R 2 and R 3 is a saturated hydrocarbon group having 4 carbon atoms. Examples of the bridged metallocene compound (P2) include R 1 ~R 4A bridged metallocene compound in which all of those other than the saturated hydrocarbon group having 4 carbon atoms are hydrogen atoms, and R 1 ~R 4 Examples thereof include a bridged metallocene compound in which two groups adjacent to the saturated hydrocarbon group having 4 carbon atoms are hydrogen atoms and the non-adjacent groups are methyl groups.

[0081] As another preferred example of the bridged metallocene compound (P1), for example, either one of R 13 and R 14 is an aryl group, and all of R 1 ~R 4 are hydrogen atoms, and a bridged metallocene compound (P3) can be mentioned.

[0082] Specific examples of the bridged metallocene compound (P) include [Dimethylmethylene(η 5 -cyclopentadienyl)(η 5 -2,7-di-tert-butylfluorenyl)]zirconium dichloride, [Dimethylmethylene(η 5 -cyclopentadienyl)(η 5 -3,6-di-tert-butylfluorenyl)]zirconium dichloride, [Dimethylmethylene(η 5 -cyclopentadienyl)(η 5 -octamethyloctahydrodibenzofluorenyl)]zirconium dichloride, [Dimethylmethylene(η 5 -cyclopentadienyl)(η 5 -tetramethyloctahydrodibenzofluorenyl)]zirconium dichloride, [Cyclohexylidene(η 5 -cyclopentadienyl)(η 5 -2,7-di-tert-butylfluorenyl)]zirconium dichloride, [Cyclohexylidene(η 5 -cyclopentadienyl)(η 5 -3,6-di-tert-butylfluorenyl)]zirconium dichloride, [Cyclohexylidene(η 5 -cyclopentadienyl)(η 5-Octamethyl octahydro dibenzofluorenyl)] zirconium dichloride, [cyclohexylidene(η 5 -cyclopentadienyl)(η 5 -tetramethyl octahydro dibenzofluorenyl)] zirconium dichloride, [Diphenylmethylene(η 5 -cyclopentadienyl)(η 5 -2,7-di-tert-butylfluorenyl)] zirconium dichloride, [Diphenylmethylene(η 5 -2-methyl-4-tert-butylcyclopentadienyl)(η 5 -2,7-di-tert-butylfluorenyl)] zirconium dichloride, [Diphenylmethylene(η 5 -cyclopentadienyl)(η 5 -3,6-di-tert-butylfluorenyl)] zirconium dichloride, [Diphenylmethylene(η 5 -cyclopentadienyl)(η 5 -octamethyl octahydro dibenzofluorenyl)] zirconium dichloride, [Diphenylmethylene{η 5 -(2-methyl-4-i-propylcyclopentadienyl)}(η 5 -octamethyl octahydro dibenzofluorenyl)] zirconium dichloride, [Diphenylmethylene(η 5 -cyclopentadienyl)(η 5 -tetramethyl octahydro dibenzofluorenyl)] zirconium dichloride, [Diphenylmethylene(η 5 -3-n-butylcyclopentadienyl)(η 5 -2,7-di-tert-butylfluorenyl)] zirconium dichloride, [Methylphenylmethylene(η 5 -cyclopentadienyl)(η 5 -2,7-di-tert-butylfluorenyl)] zirconium dichloride, [Methylphenylmethylene(η 5 -cyclopentadienyl)(η 5 -3,6-di-tert-butylfluorenyl)] zirconium dichloride, [Methylphenylmethylene(η5 -(Cyclopentadienyl)(η 5 -Octamethyl octahydro dibenzofluorenyl)]zirconium dichloride, [Methylphenylmethylene(η 5 -(Cyclopentadienyl)(η 5 -Tetramethyl octahydro dibenzofluorenyl)]zirconium dichloride, [Methyl(3-methylphenyl)methylene(η 5 -(Cyclopentadienyl)(η 5 -2,7-Di-tert-butylfluorenyl)]zirconium dichloride, [Methyl(3-methylphenyl)methylene(η 5 -(Cyclopentadienyl)(η 5 -3,6-Di-tert-butylfluorenyl)]zirconium dichloride, [Methyl(3-methylphenyl)methylene(η 5 -(Cyclopentadienyl)(η 5 -Octamethyl octahydro dibenzofluorenyl)]zirconium dichloride, [Methyl(3-methylphenyl)methylene(η 5 -(Cyclopentadienyl)(η 5 -Tetramethyl octahydro dibenzofluorenyl)]zirconium dichloride, [Methyl(4-methylphenyl)methylene(η 5 -(Cyclopentadienyl)(η 5 -2,7-Di-tert-butylfluorenyl)]zirconium dichloride, [Methyl(4-methylphenyl)methylene(η 5 -(Cyclopentadienyl)(η 5 -3,6-Di-tert-butylfluorenyl)]zirconium dichloride, [Methyl(4-methylphenyl)methylene(η 5 -(Cyclopentadienyl)(η 5 -Octamethyl octahydro dibenzofluorenyl)]zirconium dichloride, [Methyl(4-methylphenyl)methylene(η 5 -(Cyclopentadienyl)(η 5 -Tetramethyl octahydro dibenzofluorenyl)]zirconium dichloride, [Diphenylsilylene(η 5-(Cyclopentadienyl)(η 5 -2,7-Di-tert-butylfluorenyl)]zirconium dichloride, [Diphenylsilylene(η 5 -Cyclopentadienyl)(η 5 -3,6-Di-tert-butylfluorenyl)]zirconium dichloride, [Diphenylsilylene(η 5 -Cyclopentadienyl)(η 5 -Octamethyloctahydrodibenzofluorenyl)]zirconium dichloride, [Diphenylsilylene(η 5 -Cyclopentadienyl)(η 5 -Tetramethyloctahydrodibenzofluorenyl)]zirconium dichloride, [Bis(3-methylphenyl)silylene(η 5 -Cyclopentadienyl)(η 5 -2,7-Di-tert-butylfluorenyl)]zirconium dichloride, [Bis(3-methylphenyl)silylene(η 5 -Cyclopentadienyl)(η 5 -3,6-Di-tert-butylfluorenyl)]zirconium dichloride, [Bis(3-methylphenyl)silylene(η 5 -Cyclopentadienyl)(η 5 -Octamethyloctahydrodibenzofluorenyl)]zirconium dichloride, [Bis(3-methylphenyl)silylene(η 5 -Cyclopentadienyl)(η 5 -Tetramethyloctahydrodibenzofluorenyl)]zirconium dichloride, [Dicyclohexylsilylene(η 5 -Cyclopentadienyl)(η 5 -2,7-Di-tert-butylfluorenyl)]zirconium dichloride, [Dicyclohexylsilylene(η 5 -Cyclopentadienyl)(η 5 -3,6-Di-tert-butylfluorenyl)]zirconium dichloride, [Dicyclohexylsilylene(η 5 -Cyclopentadienyl)(η 5-Octamethyl octahydro dibenzofluorenyl)]zirconium dichloride, [dicyclohexylsilylene(η 5 -cyclopentadienyl)(η 5 -tetramethyl octahydro dibenzofluorenyl)]zirconium dichloride, [ethylene(η 5 -cyclopentadienyl)(η 5 -2,7-di-tert-butylfluorenyl)]zirconium dichloride, [ethylene(η 5 -cyclopentadienyl)(η 5 -3,6-di-tert-butylfluorenyl)]zirconium dichloride, [ethylene(η 5 -cyclopentadienyl)(η 5 -octamethyl octahydro dibenzofluorenyl)]zirconium dichloride, [ethylene(η 5 -cyclopentadienyl)(η 5 -tetramethyl octahydro dibenzofluorenyl)]zirconium dichloride, Ethylene[η 5 -(3-tert-butyl-5-methylcyclopentadienyl)][η 5 -(3,6-di-tert-butylfluorenyl)]zirconium dichloride, Ethylene[η 5 -(3-tert-butyl-5-methylcyclopentadienyl)][η 5 -(2,7-di-tert-butylfluorenyl)]zirconium dichloride, Ethylene[η 5 -(3-tert-butyl-5-methylcyclopentadienyl)](octamethyl octahydro dibenzofluorenyl)zirconium dichloride, Ethylene[η 5 -(3-tert-butyl-5-methylcyclopentadienyl)](benzofluorenyl)zirconium dichloride, Ethylene[η 5 -(3-tert-butyl-5-methylcyclopentadienyl)](dibenzofluorenyl)zirconium dichloride, Ethylene[η 5 -(3-tert-butyl-5-methylcyclopentadienyl)](octahydro dibenzofluorenyl)zirconium dichloride, Ethylene[η 5-(3-tert-butyl-5-methylcyclopentadienyl)][η 5 -(2,7-diphenyl-3,6-di-tert-butylfluorenyl)]zirconium dichloride, ethylene[η 5 -(3-tert-butyl-5-methylcyclopentadienyl)][η 5 -(2,7-dimethyl-3,6-di-tert-butylfluorenyl)]zirconium dichloride, ethylene[η 5 -(3-tert-butylcyclopentadienyl)][η 5 -(3,6-di-tert-butylfluorenyl)]zirconium dichloride, ethylene[η 5 -(3-tert-butylcyclopentadienyl)][η 5 -(2,7-di-tert-butylfluorenyl)]zirconium dichloride, ethylene[η 5 -(3-tert-butylcyclopentadienyl)](octamethyloctahydrodibenzofluorenyl)zirconium dichloride, ethylene[η 5 -(3-tert-butylcyclopentadienyl)](benzofluorenyl)zirconium dichloride, ethylene[η 5 -(3-tert-butylcyclopentadienyl)](dibenzofluorenyl)zirconium dichloride, ethylene[η 5 -(3-tert-butylcyclopentadienyl)](octahydrodibenzofluorenyl)zirconium dichloride, ethylene[η 5 -(3-tert-butylcyclopentadienyl)][η 5 -(2,7-diphenyl-3,6-di-tert-butylfluorenyl)]zirconium dichloride, ethylene[η 5 -(3-tert-butylcyclopentadienyl)][η 5 -(2,7-dimethyl-3,6-di-tert-butylfluorenyl)]zirconium dichloride, ethylene[η 5 -(3-n-butylcyclopentadienyl)][η 5-[η-(3,6-di-tert-butylfluorenyl)]zirconium dichloride, ethylene 5 -[η-(3-n-butylcyclopentadienyl)][η 5 -[η-(2,7-di-tert-butylfluorenyl)]zirconium dichloride, ethylene 5 -[η-(3-n-butylcyclopentadienyl)](octamethyloctahydrodibenzofluorenyl)zirconium dichloride, ethylene 5 -[η-(3-n-butylcyclopentadienyl)](benzofluorenyl)zirconium dichloride, ethylene 5 -[η-(3-n-butylcyclopentadienyl)](dibenzofluorenyl)zirconium dichloride, ethylene 5 -[η-(3-n-butylcyclopentadienyl)](octahydrodibenzofluorenyl)zirconium dichloride, ethylene 5 -[η-(3-n-butylcyclopentadienyl)][η 5 -[η-(2,7-diphenyl-3,6-di-tert-butylfluorenyl)]zirconium dichloride, ethylene 5 -[η-(3-n-butylcyclopentadienyl)][η 5 -[η-(2,7-dimethyl-3,6-di-tert-butylfluorenyl)]zirconium dichloride, diphenylmethylene[η 5 -[η-(3-tert-butyl-5-methylcyclopentadienyl)][η 5 -[η-(3,6-di-tert-butylfluorenyl)]zirconium dichloride, diphenylmethylene[η 5 -[η-(3-tert-butyl-5-methylcyclopentadienyl)][η 5 -[η-(2,7-di-tert-butylfluorenyl)]zirconium dichloride, diphenylmethylene[η 5 -[η-(3-tert-butyl-5-methylcyclopentadienyl)](octamethyloctahydrodibenzofluorenyl)zirconium dichloride, diphenylmethylene[η 5-(3-tert-Butyl-5-methylcyclopentadienyl)(benzofluorenyl)zirconium dichloride, diphenylmethylene[η 5 -(3-tert-Butyl-5-methylcyclopentadienyl)(dibenzofluorenyl)zirconium dichloride, diphenylmethylene[η 5 -(3-tert-Butyl-5-methylcyclopentadienyl)(octahydrodibenzofluorenyl)zirconium dichloride, diphenylmethylene[η 5 -(3-tert-Butyl-5-methylcyclopentadienyl)][η 5 -(2,7-Diphenyl-3,6-di-tert-butylfluorenyl)]zirconium dichloride, diphenylmethylene[η 5 -(3-tert-Butyl-5-methylcyclopentadienyl)][η 5 -(2,7-Dimethyl-3,6-di-tert-butylfluorenyl)]zirconium dichloride, Diphenylmethylene[η 5 -(3-tert-Butylcyclopentadienyl)][η 5 -(3,6-Di-tert-butylfluorenyl)]zirconium dichloride, diphenylmethylene[η 5 -(3-tert-Butylcyclopentadienyl)][η 5 -(2,7-Di-tert-butylfluorenyl)]zirconium dichloride, diphenylmethylene[η 5 -(3-tert-Butylcyclopentadienyl)(octamethyloctahydrodibenzofluorenyl)zirconium dichloride, diphenylmethylene[η 5 -(3-tert-Butylcyclopentadienyl)(benzofluorenyl)zirconium dichloride, diphenylmethylene[η 5 -(3-tert-Butylcyclopentadienyl)(dibenzofluorenyl)zirconium dichloride, diphenylmethylene[η 5 -(3-tert-Butylcyclopentadienyl)(octahydrodibenzofluorenyl)zirconium dichloride, diphenylmethylene[η 5-(3-tert-Butylcyclopentadienyl)][η 5 -(2,7-Diphenyl-3,6-di-tert-butylfluorenyl)]zirconium dichloride, diphenylmethylene[η 5 -(3-tert-Butylcyclopentadienyl)][η 5 -(2,7-Dimethyl-3,6-di-tert-butylfluorenyl)]zirconium dichloride, diphenylmethylene[η 5 -(3-n-Butylcyclopentadienyl)][η 5 -(3,6-Di-tert-butylfluorenyl)]zirconium dichloride, diphenylmethylene[η 5 -(3-n-Butylcyclopentadienyl)][η 5 -(2,7-Di-tert-butylfluorenyl)]zirconium dichloride, diphenylmethylene[η 5 -(3-n-Butylcyclopentadienyl)](octamethyloctahydrodibenzofluorenyl)zirconium dichloride, diphenylmethylene[η 5 -(3-n-Butylcyclopentadienyl)](benzofluorenyl)zirconium dichloride, diphenylmethylene[η 5 -(3-n-Butylcyclopentadienyl)](dibenzofluorenyl)zirconium dichloride, diphenylmethylene[η 5 -(3-n-Butylcyclopentadienyl)](octahydrodibenzofluorenyl)zirconium dichloride, diphenylmethylene[η 5 -(3-n-Butylcyclopentadienyl)][η 5 -(2,7-Diphenyl-3,6-di-tert-butylfluorenyl)]zirconium dichloride, diphenylmethylene[η 5 -(3-n-Butylcyclopentadienyl)][η 5 -(2,7-Dimethyl-3,6-di-tert-butylfluorenyl)]zirconium dichloride, di(p-tolyl)methylene[η 5 -(3-tert-Butyl-5-methylcyclopentadienyl)][η 5-(3,6-Di-tert-butylfluorenyl)]zirconium dichloride, di(p-tolyl)methylene[η 5 -(3-tert-butyl-5-methylcyclopentadienyl)][η 5 -(2,7-Di-tert-butylfluorenyl)]zirconium dichloride, di(p-tolyl)methylene[η 5 -(3-tert-butyl-5-methylcyclopentadienyl)](octamethyloctahydrodibenzofluorenyl)zirconium dichloride, di(p-tolyl)methylene[η 5 -(3-tert-butyl-5-methylcyclopentadienyl)](benzofluorenyl)zirconium dichloride, di(p-tolyl)methylene[η 5 -(3-tert-butyl-5-methylcyclopentadienyl)](dibenzofluorenyl)zirconium dichloride, di(p-tolyl)methylene[η 5 -(3-tert-butyl-5-methylcyclopentadienyl)](octahydrodibenzofluorenyl)zirconium dichloride, di(p-tolyl)methylene[η 5 -(3-tert-butyl-5-methylcyclopentadienyl)][η 5 -(2,7-Diphenyl-3,6-di-tert-butylfluorenyl)]zirconium dichloride, di(p-tolyl)methylene[η 5 -(3-tert-butyl-5-methylcyclopentadienyl)][η 5 -(2,7-Dimethyl-3,6-di-tert-butylfluorenyl)]zirconium dichloride, di(p-tolyl)methylene[η 5 -(3-tert-butylcyclopentadienyl)][η 5 -(3,6-Di-tert-butylfluorenyl)]zirconium dichloride, di(p-tolyl)methylene[η 5 -(3-tert-butylcyclopentadienyl)][η 5 -(2,7-Di-tert-butylfluorenyl)]zirconium dichloride, di(p-tolyl)methylene[η 5-(3-tert-butylcyclopentadienyl)(octamethyl octahydrodibenzofluorenyl)zirconium dichloride, di(p-tolyl)methylene[η 5 -(3-tert-butylcyclopentadienyl)(benzofluorenyl)zirconium dichloride, di(p-tolyl)methylene[η 5 -(3-tert-butylcyclopentadienyl)(dibenzofluorenyl)zirconium dichloride, di(p-tolyl)methylene[η 5 -(3-tert-butylcyclopentadienyl)(octahydrodibenzofluorenyl)zirconium dichloride, di(p-tolyl)methylene[η 5 -(3-tert-butylcyclopentadienyl)][η 5 -(2,7-diphenyl-3,6-di-tert-butylfluorenyl)]zirconium dichloride, di(p-tolyl)methylene[η 5 -(3-tert-butylcyclopentadienyl)][η 5 -(2,7-dimethyl-3,6-di-tert-butylfluorenyl)]zirconium dichloride, di(p-tolyl)methylene[η 5 -(3-n-butylcyclopentadienyl)][η 5 -(3,6-di-tert-butylfluorenyl)]zirconium dichloride, di(p-tolyl)methylene[η 5 -(3-n-butylcyclopentadienyl)][η 5 -(2,7-di-tert-butylfluorenyl)]zirconium dichloride, di(p-tolyl)methylene[η 5 -(3-n-butylcyclopentadienyl)(octamethyl octahydrodibenzofluorenyl)zirconium dichloride, di(p-tolyl)methylene[η 5 -(3-n-butylcyclopentadienyl)(benzofluorenyl)zirconium dichloride, di(p-tolyl)methylene[η 5 -(3-n-butylcyclopentadienyl)(dibenzofluorenyl)zirconium dichloride, di(p-tolyl)methylene[η 5-(3-n-butylcyclopentadienyl)(octahydrodibenzofluorenyl)zirconium dichloride, di(p-tolyl)methylene[η 5 -(3-n-butylcyclopentadienyl)(2,7-diphenyl-3,6-di-tert-butylfluorenyl)zirconium dichloride, di(p-tolyl)methylene[η 5 -(3-n-butylcyclopentadienyl)][η 5 -(2,7-dimethyl-3,6-di-tert-butylfluorenyl)]zirconium dichloride may be mentioned.

[0083] As the bridged metallocene compound (P), further, compounds in which the zirconium atom of the above compound is replaced with a hafnium atom or a titanium atom, compounds in which the chloro ligand is replaced with a methyl group, etc. may be exemplified. Incidentally, η 5 -tetramethyloctahydrodibenzofluorenyl is 4,4,7,7-tetramethyl-(5a,5b,11a,12,12a-η 5 )-1,2,3,4,7,8,9,10-octahydrodibenz[b,H]fluorenyl group, η 5 -octamethyloctahydrodibenzofluorenyl is 1,1,4,4,7,7,10,10-octamethyl-(5a,5b,11a,12,12a-η 5 )-1,2,3,4,7,8,9,10-octahydrodibenz[b,H]fluorenyl group, respectively. The bridged metallocene compound (P) may be used alone or in combination of two or more.

[0084] <Compound (Q)> The compound (Q) is at least one compound selected from the group consisting of an organometallic compound (Q-1), an organoaluminum oxy compound (Q-2), and a compound (Q-3) that reacts with the bridged metallocene compound (P) to form an ion pair.

[0085] As the organometallic compound (Q-1), specifically, organometallic compounds (Q-1a), (Q-1b), and (Q-1c) of Groups 1, 2, 12, or 13 of the periodic table as described below can be mentioned. (Q-1a) Formula R a m Al(OR b ) n H p X q An organoaluminum compound represented by. (In the formula, R a and R b may be the same as or different from each other, and represent a hydrocarbon group having 1 to 15 carbon atoms, preferably 1 to 4 carbon atoms. X represents a halogen atom. m is a number where 0 < m ≦ 3, n is a number where 0 ≦ n < 3, p is a number where 0 ≦ p < 3, q is a number where 0 ≦ q < 3, and m + n + p + q = 3.)

[0086] As such a compound, Tri-n-alkylaluminum such as trimethylaluminum, triethylaluminum, tri-n-butylaluminum, tri-n-hexylaluminum, tri-n-octylaluminum, Tri-branched alkylaluminum such as triisopropylaluminum, triisobutylaluminum, tri-sec-butylaluminum, tri-tert-butylaluminum, tri-2-methylbutylaluminum, tri-3-methylhexylaluminum, tri-2-ethylhexylaluminum, Tricycloalkylaluminum such as tricyclohexylaluminum, tricyclooctylaluminum, Triarylaluminum such as triphenylaluminum, tri(4-methylphenyl)aluminum, Formula (i-C4H9) x Al y (C5H 10 ) z (In the formula, x, y, and z are positive numbers, and z ≦ 2x.) An alkenylaluminum such as isoprenylaluminum represented by, Alkylaluminum alkoxides (monoalkylaluminum alkoxides) such as isobutylaluminum methoxide and isobutylaluminum ethoxide, Dialkylaluminum alkoxides such as dimethylaluminum methoxide, diethylaluminum ethoxide, and dibutylaluminum butoxide, Alkylaluminum sesquialkoxides such as ethylaluminum sesquiethoxide and butylaluminum sesquibutoxide, Formula R a 2.5 Al(OR b ) 0.5 Partially alkoxylated alkylaluminum having an average composition represented by etc., Dialkylaluminum aryloxides such as diethylaluminum phenoxide and diethylaluminum (2,6 - di - tert - butyl - 4 - methylphenoxide), Dialkylaluminum halides such as dimethylaluminum chloride, diethylaluminum chloride, dibutylaluminum chloride, diethylaluminum bromide, and diisobutylaluminum chloride, Alkylaluminum sesquihalides such as ethylaluminum sesquichloride, butylaluminum sesquichloride, and ethylaluminum sesquibromide, Partially halogenated alkylaluminum such as alkylaluminum dihalides like ethylaluminum dichloride, Dialkylaluminum hydrides such as diethylaluminum hydride, diisopropylaluminum hydride, dibutylaluminum hydride, and diisobutylaluminum hydride, Alkylaluminum dihydrides such as ethylaluminum dihydride and propylaluminum dihydride, and other partially hydrogenated alkylaluminum, Partially alkoxylated and halogenated alkylaluminum such as ethylaluminum ethoxychloride, butylaluminum butoxychloride, and ethylaluminum ethoxybromide, etc. can be exemplified. Also, the above formula Ra m Al(OR b ) n H p X q Compounds similar to the compounds represented by can also be used. For example, organoaluminum compounds in which two or more aluminum compounds are bonded via a nitrogen atom can be mentioned. Specific examples of such compounds include (C2H5)2AlN(C2H5)Al(C2H5)2 and the like.

[0087] (Q-1b) The complex alkyl compound of a Group 1 metal and aluminum in the periodic table represented by the formula M 2 AlR a 4. (In the formula, M 2 represents Li, Na or K, and R a represents a hydrocarbon group having 1 to 15 carbon atoms, preferably 1 to 4 carbon atoms.) Examples of such compounds include LiAl(C2H5)4, LiAl(C7H 15 )4 and the like.

[0088] (Q-1c) The dialkyl compound of a Group 2 or Group 12 metal in the periodic table represented by the formula R a R b M 3 (In the formula, R a and R b may be the same as or different from each other, and represent a hydrocarbon group having 1 to 15 carbon atoms, preferably 1 to 4 carbon atoms, and M 3 is Mg, Zn or Cd.) As the organoaluminum oxy compound (Q-2), conventionally known aluminoxane can be used as it is. Specifically, compounds represented by the following formula [III] and compounds represented by the following formula [IV] can be mentioned.

[0089]

Chemical formula

[0090] Particularly, methylaluminoxane in which R is a methyl group and n is 3 or more, preferably 10 or more, is used. Even if a small amount of an organoaluminum compound is mixed in these aluminoxanes, it does not matter.

[0091] In the present invention, when copolymerizing ethylene and an α-olefin having 3 or more carbon atoms at a high temperature, a benzene-insoluble organoaluminum oxy compound as exemplified in JP-A-2-78687 can also be applied. Further, an organoaluminum oxy compound described in JP-A-2-167305, an aluminoxane having two or more alkyl groups described in JP-A-2-24701 and JP-A-3-103407, etc. can also be preferably used. The "benzene-insoluble organoaluminum oxy compound" that may be used in the present invention means that the Al component dissolved in benzene at 60 °C is usually 10% or less, preferably 5% or less, particularly preferably 2% or less in terms of Al atoms, and is a compound insoluble or hardly soluble in benzene.

[0092] Further, examples of the organoaluminum oxy compound (Q-2) include modified methylaluminoxane represented by the following formula [V].

[0093]

Chemical formula

[0094] Methylaluminoxane, an example of the organoaluminum oxy compound (Q-2), is readily available and has high polymerization activity, so it is generally used as an activator in olefin polymerization. However, since methylaluminoxane is difficult to dissolve in saturated hydrocarbons, it has been used as a solution of aromatic hydrocarbons such as toluene or benzene, which is not environmentally desirable. For this reason, in recent years, a flexible body of methylaluminoxane represented by the formula [V] has been developed and used as aluminoxane dissolved in saturated hydrocarbons. This modified methylaluminoxane represented by the formula [V] is prepared using trimethylaluminum and an alkylaluminum other than trimethylaluminum, for example, using trimethylaluminum and triisobutylaluminum, as shown in, for example, U.S. Patent No. 4,960,878 and U.S. Patent No. 5,041,584. Aluminoxane in which Rx is an isobutyl group is commercially available under the trade names MMAO and TMAO in the form of a saturated hydrocarbon solution (see Tosoh Finechem Corporation, Tosoh Research & Technology Review, Vol 47, 55 (2003)).

[0095] Furthermore, examples of the organoaluminum oxy compound (Q-2) include an organoaluminum oxy compound containing boron represented by the following formula [VI].

[0096] [Chemical formula] In formula [VI], R c represents a hydrocarbon group having 1 to 10 carbon atoms. R d may be the same as or different from each other and represents a hydrogen atom, a halogen atom or a hydrocarbon group having 1 to 10 carbon atoms.

[0097] Compounds (Q-3) that react with the bridging metallocene compound (P) to form an ion pair (hereinafter sometimes abbreviated as "ionized ionic compound" or simply "ionic compound") include Lewis acids, ionic compounds, borane compounds, and carborane compounds described in JP-T-1-501950, JP-T-1-502036, JP-A-3-179005, JP-A-3-179006, JP-A-3-207703, JP-A-3-207704, US Patent No. 5321106, etc. Furthermore, heteropoly compounds and isopoly compounds can also be mentioned.

[0098] The ionized ionic compound preferably used in the present invention is a boron compound represented by the following formula [VII].

[0099] [Chemical formula] In formula [VII], R e+ is, for example, H + , a carbenium cation, an oxonium cation, an ammonium cation, a phosphonium cation, a cycloheptyltrienyl cation, a ferrocenium cation having a transition metal, etc. R f ~R i may be the same as or different from each other, and is a substituent selected from the group consisting of hydrocarbon groups having 1 to 20 carbon atoms, silicon-containing groups, nitrogen-containing groups, oxygen-containing groups, halogen atoms, and halogen-containing groups, and is preferably a substituted aryl group.

[0100] Specific examples of the above carbenium cation include trisubstituted carbenium cations such as triphenylcarbenium cation, tris(4-methylphenyl)carbenium cation, and tris(3,5-dimethylphenyl)carbenium cation.

[0101] Specific examples of the ammonium cation include trialkyl-substituted ammonium cations such as trimethylammonium cation, triethylammonium cation, tri(n-propyl)ammonium cation, triisopropylammonium cation, tri(n-butyl)ammonium cation, and triisobutylammonium cation; N,N-dialkylanilinium cations such as N,N-dimethylanilinium cation, N,N-diethylanilinium cation, and N,N-2,4,6-pentamethylanilinium cation; and dialkylammonium cations such as diisopropylammonium cation and dicyclohexylammonium cation.

[0102] Specific examples of the phosphonium cation include triarylphosphonium cations such as triphenylphosphonium cation, tris(4-methylphenyl)phosphonium cation, and tris(3,5-dimethylphenyl)phosphonium cation.

[0103] R e+ Among the above specific examples, carbocation, ammonium cation, etc. are preferable, and particularly triphenylcarbocation, N,N-dimethylanilinium cation, and N,N-diethylanilinium cation are preferable.

[0104] Among the ionizable ionic compounds preferably used in the present invention, examples of the compound containing a carbocation include triphenylcarbenium tetraphenylborate, triphenylcarbenium tetrakis(pentafluorophenyl)borate, triphenylcarbenium tetrakis{3,5-di-(trifluoromethyl)phenyl}borate, tris(4-methylphenyl)carbenium tetrakis(pentafluorophenyl)borate, and tris(3,5-dimethylphenyl)carbenium tetrakis(pentafluorophenyl)borate.

[0105] Among the ionized ionic compounds preferably used in the present invention, as compounds containing a trialkyl-substituted ammonium cation, triethylammonium tetraphenylborate, tripropylammonium tetraphenylborate, tri(n-butyl)ammonium tetraphenylborate, trimethylammonium tetrakis(4-methylphenyl)borate, trimethylammonium tetrakis(2-methylphenyl)borate, tri(n-butyl)ammonium tetrakis(pentafluorophenyl)borate, triethylammonium tetrakis(pentafluorophenyl)borate, tripropylammonium tetrakis(pentafluorophenyl)borate, tripropylammonium tetrakis(2,4-dimethylphenyl)borate, tri(n-butyl)ammonium tetrakis(3,5-dimethylphenyl)borate, tri(n-butyl)ammonium tetrakis{4-(trifluoromethyl)phenyl}borate, tri(n-butyl)ammonium tetrakis{3,5-di(trifluoromethyl)phenyl}borate, tri(n-butyl)ammonium tetrakis(2-methylphenyl)borate, dioctadecylmethylammonium tetraphenylborate, dioctadecylmethylammonium tetrakis(4-methylphenyl)borate, dioctadecylmethylammonium tetrakis(pentafluorophenyl)borate, dioctadecylmethylammonium tetrakis(2,4-dimethylphenyl)borate, dioctadecylmethylammonium tetrakis(3,5-dimethylphenyl)borate, dioctadecylmethylammonium tetrakis{4-(trifluoromethyl)phenyl}borate, dioctadecylmethylammonium tetrakis{3,5-di(trifluoromethyl)phenyl}borate, dioctadecylmethylammonium, etc. can be exemplified.

[0106] Among the ionized ionic compounds preferably used in the present invention, examples of the compounds containing an N,N-dialkylanilinium cation include N,N-dimethylanilinium tetraphenylborate, N,N-dimethylanilinium tetrakis(pentafluorophenyl)borate, N,N-dimethylanilinium tetrakis{3,5-di(trifluoromethyl)phenyl}borate, N,N-diethylanilinium tetraphenylborate, N,N-diethylanilinium tetrakis(pentafluorophenyl)borate, N,N-diethylanilinium tetrakis{3,5-di(trifluoromethyl)phenyl}borate, N,N-2,4,6-pentamethylanilinium tetraphenylborate, N,N-2,4,6-pentamethylanilinium tetrakis(pentafluorophenyl)borate, and the like.

[0107] Among the ionized ionic compounds preferably used in the present invention, examples of the compounds containing a dialkylammonium cation include di-n-propylammonium tetrakis(pentafluorophenyl)borate, dicyclohexylammonium tetraphenylborate, and the like.

[0108] In addition, the ionic compounds exemplified by JP-A-2004-51676 can also be used without limitation. The above ionic compound (Q-3) may be used alone or in combination of two or more.

[0109] <Constitutional examples of metallocene catalysts> Examples of the constitutional examples of the metallocene catalyst include the following [1] to [4]. [1] Containing a bridged metallocene compound (P) and a compound (Q-2) [2] Containing a bridged metallocene compound (P), a compound (Q-1), and a compound (Q-2) [3] Containing a bridged metallocene compound (P), a compound (Q-1), and a compound (Q-3) [4] Containing a bridged metallocene compound (P), a compound (Q-2), and a compound (Q-3) The crosslinked metallocene compound (P) and the compounds (Q-1) to (Q-3) may be introduced into the reaction system in any order.

[0110] <Support (R)> The metallocene catalyst containing the crosslinked metallocene compound (P) and the compound (Q) may further contain a support (R).

[0111] The support (R) that may be used in the present invention is an inorganic or organic compound and is a granular or particulate solid. Among these, as the inorganic compound, porous oxides, inorganic chlorides, clays, clay minerals or ion-exchangeable layered compounds are preferable.

[0112] As the porous oxide, specifically, SiO2, Al2O3, MgO, ZrO, TiO2, B2O3, CaO, ZnO, BaO, ThO2, etc., or a composite or mixture containing these, for example, natural or synthetic zeolite, SiO2-MgO, SiO2-Al2O3, SiO2-TiO2, SiO2-V2O5, SiO2-Cr2O3, SiO2-TiO2-MgO, etc. can be used. Among these, those mainly composed of SiO2 and / or Al2O3 are preferable. Such porous oxides have different properties depending on the type and production method, but the support preferably used in the present invention has a particle size of 0.5 to 300 μm, preferably 1.0 to 200 μm, and a specific surface area of 50 to 1000 m 2 / g, preferably 100 to 700 m 2 / g, and the pore volume is in the range of 0.3 to 3.0 cm 3 / g. Such a support is used after being calcined at 100 to 1000 °C, preferably 150 to 700 °C, if necessary.

[0113] As the inorganic chloride, MgCl2, MgBr2, MnCl2, MnBr2, etc. are used. The inorganic chloride may be used as it is, or may be used after being pulverized by a ball mill or a vibration mill. Also, after dissolving the inorganic chloride in a solvent such as alcohol, a precipitate obtained by precipitating it into fine particles with a precipitating agent may be used.

[0114] Clay is usually composed mainly of clay minerals. An ion-exchangeable layered compound is a compound having a crystal structure in which the constituting planes are stacked parallel to each other with a weak binding force by an ionic bond or the like, and the contained ions are exchangeable. Most clay minerals are ion-exchangeable layered compounds. Further, as these clays, clay minerals, and ion-exchangeable layered compounds, not only naturally occurring ones but also synthetic products can be used. Further, examples of the clay, clay mineral, or ion-exchangeable layered compound include clay, clay mineral, and ion-crystalline compounds having a layered crystal structure such as a hexagonal close-packed type, an antimony type, a CdCl2 type, and a CdI2 type. Examples of such clays and clay minerals include kaolin, bentonite, kibushi clay, gyrolite clay, allophane, hisingerite, pyrophyllite, umo group, montmorillonite group, vermiculite, riokite group, palygorskite, kaolinite, nacrite, dickite, halloysite, etc. Examples of the ion-exchangeable layered compound include crystalline acidic salts of polyvalent metals such as α-Zr(HAsO4)2·H2O, α-Zr(HPO4)2, α-Zr(KPO4)2·3H2O, α-Ti(HPO4)2, α-Ti(HAsO4)2·H2O, α-Sn(HPO4)2·H2O, γ-Zr(HPO4)2, γ-Ti(HPO4)2, γ-Ti(NH4PO4)2·H2O. It is also preferable to subject the clay and clay minerals used in the present invention to chemical treatment. As the chemical treatment, any of a surface treatment for removing impurities adhering to the surface, a treatment that affects the crystal structure of the clay, etc. can be used. Specific examples of the chemical treatment include acid treatment, alkali treatment, salt treatment, organic substance treatment, etc.

[0115] Ion-exchangeable layered compounds may be layered compounds in a state where the interlayer is expanded by utilizing ion-exchangeability and exchanging the exchangeable ions between layers with another large and bulky ion. Such bulky ions play a supporting role in supporting the layered structure and are usually called pillars. Further, introducing another substance (guest compound) into the interlayer of such a layered compound is called intercalation. Examples of guest compounds include cationic inorganic compounds such as TiCl4 and ZrCl4, metal alkoxides such as Ti(OR)4, Zr(OR)4, PO(OR)3, and B(OR)3 (where R is a hydrocarbon group, etc.), 13 O4(OH) 24 7+ 、[Zr4(OH) 14 2+ 、[Fe3O(OCOCH3)6] + and metal hydroxide ions such as. These compounds are used alone or in combination of two or more. Further, when intercalating these compounds, polymers obtained by hydrolysis and polycondensation of metal alkoxides such as Si(OR)4, Al(OR)3, and Ge(OR)4 (where R is a hydrocarbon group, etc.), colloidal inorganic compounds such as SiO2, etc. can also coexist. Examples of pillars include oxides formed by heating and dehydrating after intercalating the above metal hydroxide ions between layers.

[0116] Among these, preferred ones are clay or clay minerals, and particularly preferred ones are montmorillonite, vermiculite,pectolite, teniolite and synthetic mica. Examples of the organic compound as the carrier (R) include granular or fine particulate solids having a particle size in the range of 0.5 to 300 μm. Specifically, (co)polymers produced mainly from α-olefins having 2 to 14 carbon atoms such as ethylene, propylene, 1-butene, and 4-methyl-1-pentene, (co)polymers produced mainly from vinylcyclohexane and styrene, and modified products thereof can be exemplified.

[0117] <Conditions for polymerization using metallocene catalysts>​​ The usage method and the addition order of each component constituting the above metallocene catalyst are arbitrarily selected. Further, at least two or more of the components in the catalyst may be contacted in advance. The crosslinked metallocene compound (P) (hereinafter also referred to as "component (P)") is usually 1×10 -9 ~1×10 -1 mol, preferably 1×10 -8 ~1×10 -2 mol per liter of the reaction volume.

[0118] The organometallic compound (Q-1) (hereinafter also referred to as "component (Q-1)") is used in such an amount that the molar ratio [(Q-1) / M] between the component (Q-1) and the transition metal atom (M) in the component (P) is usually 0.01 to 50,000, preferably 0.05 to 10,000.

[0119] The organoaluminum oxy compound (Q-2) (hereinafter also referred to as "component (Q-2)") is used in such an amount that the molar ratio [(Q-2) / M] between the aluminum atom in the component (Q-2) and the transition metal atom (M) in the component (P) is usually 10 to 5,000, preferably 20 to 2,000.

[0120] The ionic compound (Q-3) (hereinafter also referred to as "component (Q-3)") is used in such an amount that the molar ratio [(Q-3) / M] between the component (Q-3) and the transition metal atom (M) in the component (P) is usually 1 to 10,000, preferably 1 to 5,000.

[0121] The polymerization temperature is usually -50°C to 300°C, preferably 30°C to 250°C, more preferably 100°C to 250°C, and even more preferably 130°C to 200°C. In the polymerization temperature range of the above range, as the temperature increases, the solution viscosity during polymerization decreases, and the removal of the polymerization heat becomes easier. The polymerization pressure is usually normal pressure to 10 MPa gauge pressure (MPa-G), preferably normal pressure to 8 MPa-G.

[0122] The polymerization reaction can be carried out by any of the batch, semi - continuous, and continuous methods. Furthermore, it is also possible to continuously carry out the polymerization in two or more polymerization reactors with different reaction conditions. The molecular weight of the resulting copolymer can be adjusted by changing the hydrogen concentration and polymerization temperature in the polymerization system. Furthermore, it can also be adjusted by the amount of the compound (Q) used. When adding hydrogen, the amount is preferably about 0.001 - 5,000 NL per 1 kg of the copolymer to be produced.

[0123] The polymerization solvent used in the liquid - phase polymerization method is usually an inert hydrocarbon solvent, preferably a saturated hydrocarbon having a boiling point of 50°C to 200°C under normal pressure. Specifically, as the polymerization solvent, there are aliphatic hydrocarbons such as propane, butane, pentane, hexane, heptane, octane, decane, dodecane, and kerosene, and alicyclic hydrocarbons such as cyclopentane, cyclohexane, and methylcyclopentane. Particularly preferred are hexane, heptane, octane, decane, and cyclohexane. The α - olefin itself to be polymerized can also be used as the polymerization solvent. In addition, aromatic hydrocarbons such as benzene, toluene, and xylene, and halogenated hydrocarbons such as ethylene chloride, chlorobenzene, and dichloromethane can also be used as the polymerization solvent, but from the viewpoints of reducing the environmental load and minimizing the impact on human health, their use is not preferred.

[0124] 〔Vanadium - based catalyst〕 In the present invention, a vanadium - based catalyst can also be used as the olefin polymerization catalyst for obtaining the ethylene·α - olefin copolymer (B0). The vanadium - based catalyst that can be used for the production of the ethylene·α - olefin copolymer (B0) consists of a soluble vanadium compound (V) and an organoaluminum compound (Q').

[0125] <Soluble vanadium compound (V)> The soluble vanadium compound (V) constituting the vanadium - based catalyst that can be used in the present invention is specifically represented by the following general formula. VO(OR) a X b or V(OR) c X d In the formula, R represents a hydrocarbon group such as an alkyl group, a cycloalkyl group, or an aryl group, X represents a halogen atom, and a, b, c, and d satisfy 0 ≦ a ≦ 3, 0 ≦ b ≦ 3, 2 ≦ a + b ≦ 3, 0 ≦ c ≦ 4, 0 ≦ d ≦ 4, and 3 ≦ c + d ≦ 4, respectively.

[0126] Specific examples of the soluble vanadium compound (V) represented by the above general formula include VOCl3, VO(OCH3)Cl2, VO(OC2H5)Cl2, VO(OC2H5) 1.5 Cl 1.5 , VO(OC2H5)2Cl, VO(O n-C3H7)Cl2, VO(O iso-C3H7)Cl2, VO(O n-C4H9)Cl2, VO(O iso-C4H9)Cl2, VO(O sec-C4H9)Cl2, VO(O t-C4H9)Cl2, VO(OC2H5)3, VOBr2, VCl4, VOCl2, VO(O n-C4H9)3, VOCl3·2OC8H 17 OH, etc.

[0127] <Organic aluminum compound (Q’)> The organic aluminum compound (Q’) constituting the vanadium-based catalyst is the same as the organic aluminum compound (Q-1a) described above in the above “metallocene-based catalyst”, and the exemplified compounds thereof are also the same as the compounds exemplified for the organic aluminum compound (Q-1a). The organic aluminum compound (Q’) may be, for example, ethylaluminum sesquichloride.

[0128] <Polymerization conditions using the vanadium-based catalyst> The usage and addition order of each component constituting the above vanadium-based catalyst are arbitrarily selected. The soluble vanadium compound (V) is usually 1×10 per liter of the reaction volume -5 ~5×10 -3 mol, preferably 5×10 -5 ~3×10 -3It is used in an amount to become mol. The organoaluminum compound (Q') is used in an amount such that the molar ratio [(Q') / M] of the organoaluminum compound (Q') to the vanadium atom (M) in the soluble vanadium compound (V) is usually 2 to 50, preferably 3 to 20. The polymerization temperature is usually -50°C to 100°C, preferably -30 to 80°C, more preferably -20°C to 60°C. The polymerization pressure is usually atmospheric pressure to 5 MPa gauge pressure (MPa-G), preferably atmospheric pressure to 2 MPa-G. The polymerization reaction can be carried out by any of the batch, semi-continuous, and continuous methods. Further, it is also possible to continuously carry out the polymerization in two or more polymerization reactors having different reaction conditions. The molecular weight of the obtained copolymer can be adjusted by changing the hydrogen concentration and polymerization temperature in the polymerization system. Further, it can also be adjusted by the amount of the organoaluminum compound (Q') used. The polymerization solvent used in the liquid phase polymerization method is usually an inert hydrocarbon solvent, preferably a saturated hydrocarbon having a boiling point of 50°C to 200°C under atmospheric pressure. The polymerization solvent may be, for example, the solvent exemplified in the above "Conditions for Polymerization Using a Metallocene Catalyst".

[0129] Requirement (b-2) The graft-modified ethylene·α-olefin copolymer (B) contains a graft portion derived from an ethylenically unsaturated monomer having a hydroxyl group. Here, the "graft portion derived from an ethylenically unsaturated monomer having a hydroxyl group" means a graft portion containing one or more structural units corresponding to the "ethylenically unsaturated monomer having a hydroxyl group". For example, an ethylenically unsaturated monomer having a hydroxyl group is represented as R H1 R H2 C=CR H3 R H4 (R H1 、R H2 、R H3 and R H4 are each independently a hydrogen atom or a hydrocarbon group, and the hydrocarbon group may contain a functional group containing a hetero atom, RH1 , R H2 , R H3 and R H4 When one or more selected from the group consisting of are represented as having a hydroxyl group), the "graft portion derived from an ethylenically unsaturated monomer having a hydroxyl group" is -[R H1 R H2 C-CR H3 R H4 n H - (n H is an integer of 1 or more) and contains a structure represented by

[0130] Ethylenically unsaturated monomer having a hydroxyl group The ethylenically unsaturated monomer having a hydroxyl group used in the present invention is a compound having a hydroxyl group and an ethylenically unsaturated bond in the molecule, and examples thereof include (meth) acrylic esters having a hydroxyl group in the ester part, unsaturated alcohols, hydroxyl group-containing styrene derivatives, and hydroxyvinyl ethers. Among these, unsaturated alcohols are preferred from the viewpoints of compatibility and transparency with the (meth) acrylic resin (A).

[0131] Examples of the (meth) acrylic ester having a hydroxyl group in the ester part include mono (meth) acrylate compounds of polyhydric alcohols, and specific examples include 2-hydroxyethyl (meth) acrylate, 2-hydroxypropyl (meth) acrylate, 3-hydroxypropyl (meth) acrylate, 2-hydroxy-3-phenoxypropyl (meth) acrylate, glycerin mono (meth) acrylate, pentaerythritol mono (meth) acrylate, polyethylene glycol mono (meth) acrylate, and the like.

[0132] Specific examples of the unsaturated alcohol include allyl alcohol, 2-methyl-3-buten-1-ol, 2-methyl-3-buten-2-ol, 3-methyl-3-buten-1-ol, 10-undecen-1-ol, 1-octen-3-ol, 2-methoxynorbornene, 2-butene-1,4-diol, and the like. Among these, 2-methyl-3-buten-1-ol and 2-methyl-3-buten-2-ol are preferred.

[0133] Specific examples of the hydroxyl group-containing styrene derivative include hydroxystyrene and the like. Specific examples of the hydroxyvinyl ether include hydroxymethyl vinyl ether, hydroxyethyl vinyl ether, hydroxypropyl vinyl ether, hydroxybutyl vinyl ether, hydroxymethyl propenyl ether, hydroxyethyl propenyl ether, hydroxypropyl propenyl ether, hydroxybutyl propenyl ether, hydroxymethyl butenyl ether, hydroxyethyl butenyl ether, hydroxypropyl butenyl ether, hydroxybutyl butenyl ether, and the like.

[0134] In addition, as the ethylenically unsaturated monomer having a hydroxyl group, N-methylolacrylamide, 2-(meth)acryloyloxyethyl acetyl phosphate, glycerin monoallyl ether, allyloxyethanol, and the like can also be used. The ethylenically unsaturated monomer having a hydroxyl group can be used alone or in combination of two or more.

[0135] Requirement (b-3) The graft-modified ethylene / α-olefin copolymer (B) of the present invention is a graft-modified ethylene / α-olefin copolymer containing a main chain portion derived from an ethylene / α-olefin copolymer and a graft portion derived from the ethylenically unsaturated monomer having the above-mentioned hydroxyl group. Here, from the viewpoint of reducing bleed-out and obtaining a sufficient flexibility-imparting effect, the graft-modified ethylene / α-olefin copolymer (B) preferably has a graft portion ratio in the range of 0.1% by mass or more and less than 70% by mass, more preferably 0.5% by mass or more and less than 50% by mass, still more preferably 1.0% by mass or more and less than 30% by mass (however, the total amount of the main chain portion and the graft portion is taken as 100% by mass).

[0136] When the ratio of the graft portion is less than the above lower limit value, particularly less than 0.1% by mass, the compatibility with the acrylic resin (A) may decrease, which may cause bleed-out. On the other hand, when the ratio of the graft portion is equal to or more than the above upper limit value, particularly 70% by mass or more, the effect of improving fluidity may decrease, and a sufficient flexibility-imparting effect may not be obtained.

[0137] Requirement (b-4) The graft-modified ethylene / α-olefin copolymer (B) according to the present invention preferably has a weight average molecular weight (Mw) of 1,500 to 30,000 in terms of polystyrene as determined by gel permeation chromatography (GPC) from the viewpoint of reducing bleed-out, and more preferably a weight average molecular weight (Mw) of 1,500 to 20,000. In one particularly preferred embodiment of the present invention, the weight average molecular weight (Mw) is 1,500 to 12,000. However, the weight average molecular weight (Mw) may exceed 12,000, for example, it may be about 18,000 (for example, 17,000 to 19,000).

[0138] When the weight average molecular weight (Mw) is below the above lower limit, particularly less than 1,500, it may cause bleed - out due to the presence of low - molecular - weight components. On the other hand, when the weight average molecular weight (Mw) exceeds the above upper limit, particularly greater than 30,000, the compatibility with the (meth)acrylic resin (A) decreases, which may also cause bleed - out. In order to surely obtain both sufficiently high low - temperature flexibility and sufficiently high adhesiveness when forming an adhesive layer, it may be preferable to reduce the weight average molecular weight (Mw) of the graft - modified ethylene·α - olefin copolymer (B) to some extent (for example, 10,000 or less, and in some cases, 6,000 or less).

[0139] Requirement (b-5) The graft - modified ethylene·α - olefin copolymer (B) according to the present invention preferably has a kinematic viscosity at 100°C of 10 to 5,000 mm 2 / s, more preferably 15 to 4,000 mm 2 / s, and even more preferably 20 to 3,000 mm 2 / s from the viewpoint of reducing bleed - out.

[0140] When the kinematic viscosity at 100°C is below the above lower limit, particularly less than 10 mm 2 / s, it may cause bleed - out due to the presence of highly fluid components. When the kinematic viscosity at 100°C exceeds the above upper limit, particularly greater than 5,000 mm 2 / s, the dispersibility in the (meth)acrylic resin (A) decreases due to the high - viscosity components, which may cause bleed - out. In order to surely obtain both sufficiently high low - temperature flexibility and sufficiently high adhesiveness when forming an adhesive layer, it may be preferable to reduce the kinematic viscosity at 100°C of the graft - modified ethylene·α - olefin copolymer (B) to some extent (for example, 1,000 mm 2 / s or less, and in some cases, 500 mm 2 / s or less).

[0141] Requirement (b-6) The graft-modified ethylene-α-olefin copolymer (B) according to the present invention preferably has no melting point observed by differential scanning calorimetry (DSC). Here, the non-observation of the melting point means that the heat of fusion (ΔH) (unit: J / g) measured by differential scanning calorimetry (DSC) is not substantially measured. The fact that the heat of fusion (ΔH) is not substantially measured means that no peak is observed in the differential scanning calorimeter (DSC) measurement, or the observed heat of fusion is 1 J / g or less. The non-observation of the melting point is preferable because it can improve fluidity, improve compatibility with the (meth)acrylic resin (A), and impart flexibility at low temperatures.

[0142] Requirement (b-7) The graft-modified ethylene-α-olefin copolymer (B) according to the present invention preferably has a molecular weight distribution (Mw / Mn) of 3.5 or less, more preferably 3.0 or less, as determined by gel permeation chromatography (GPC), from the viewpoint of reducing bleed-out. In one particularly preferred embodiment of the present invention, the molecular weight distribution (Mw / Mn) is 2.5 or less. However, the molecular weight distribution (Mw / Mn) may exceed 2.5, for example, it may be about 2.9. When the molecular weight distribution (Mw / Mn) exceeds the above upper limit, particularly when it is greater than 3.5, bleed-out may occur due to low molecular weight components and high molecular weight components with low compatibility.

[0143] Production method of graft-modified ethylene·α-olefin copolymer (B) The graft-modified ethylene-α-olefin copolymer (B) according to the present invention can be prepared using various conventionally known methods. For example, it can be prepared by adding the ethylenically unsaturated monomer having a hydroxyl group to the above ethylene-α-olefin copolymer (B0) and performing graft copolymerization. Here, the above ethylene-α-olefin copolymer (B0) can be obtained by the method described above in the section "Method for Producing Ethylene-α-Olefin Copolymer (B0)", and can be produced, for example, by the following method (α) or method (β).

[0144] Method (α): In the presence of a catalyst system containing at least one compound (Q) selected from the group consisting of a crosslinked metallocene compound (P) represented by the following (Formula 1), an organometallic compound (Q-1), an organoaluminum oxy compound (Q-2), and a compound (Q-3) that reacts with the crosslinked metallocene compound (P) to form an ion pair, ethylene and an α-olefin are solution-polymerized to obtain an ethylene·α-olefin copolymer (B0) in step (SB1); A step (SB2) of adding the ethylenically unsaturated monomer having a hydroxyl group described above in the above requirement (b-2) to the ethylene·α-olefin copolymer (B0) and subjecting it to graft copolymerization; A method comprising:

[0145] [Chemical formula] Y, M, R in (Formula 1) 1 ~R 14 , Q and j are the same as Y, M, R 1 ~R 14 , Q and j described above in the section of "Method for Producing Ethylene·α-Olefin Copolymer (B0)", respectively. Also, the organometallic compound (Q-1), the organoaluminum oxy compound (Q-2), and the compound (Q-3) are the same as the organometallic compound (Q-1), the organoaluminum oxy compound (Q-2), and the compound (Q-3) described above in the section of "Method for Producing Ethylene·α-Olefin Copolymer (B0)", respectively.

[0146] Method (β): In the presence of a vanadium-based catalyst composed of a soluble vanadium compound (V) and an organoaluminum compound (Q'), ethylene and an α-olefin are solution-polymerized to obtain an ethylene·α-olefin copolymer (B0) in step (SB1'); A step (SB2) of adding the ethylenically unsaturated monomer having a hydroxyl group described above in the above requirement (b-2) to the ethylene·α-olefin copolymer (B0) and subjecting it to graft copolymerization; A method comprising:

[0147] Here, the soluble vanadium compound (V) and the organoaluminum compound (Q') are the same as the soluble vanadium compound (V) and the organoaluminum compound (Q') described above in the section of "Method for Producing Ethylene·α-Olefin Copolymer (B0)", respectively.

[0148] Here, the graft copolymerization of the ethylene·α-olefin copolymer (B0) with the ethylenically unsaturated monomer having a hydroxyl group can be carried out, for example, by the method shown in the following (1) or (2).

[0149] (1) A method in which the ethylene·α-olefin copolymer (B0) is mixed in an extruder, a batch reactor, etc., and the ethylenically unsaturated monomer having a hydroxyl group is added for graft copolymerization. (2) A method in which the ethylene·α-olefin copolymer (B0) is dissolved in a solvent, and the ethylenically unsaturated monomer having a hydroxyl group is added for graft copolymerization.

[0150] In any method, in order to efficiently graft copolymerize the ethylenically unsaturated monomer having a hydroxyl group onto the ethylene·α-olefin copolymer (B0), it is preferable to carry out the graft reaction in the presence of a radical initiator. As the radical initiator, for example, organic peroxides, azo compounds, etc. are used.

[0151] Examples of the organic peroxide include benzoyl peroxide, dichlorobenzoyl peroxide, dicumyl peroxide, di-tert-butyl peroxide, etc., and examples of the azo compound include azobisisobutyronitrile, dimethylazoisobutyrate, etc.

[0152] Specific examples of such radical initiators preferably used include dialkyl peroxides such as dicumyl peroxide, di-tert-butyl peroxide, 2,5-dimethyl-2,5-di(tert-butylperoxy)hexine-3, 2,5-dimethyl-2,5-di(tert-butylperoxy)hexane, and 1,4-bis(tert-butylperoxyisopropyl)benzene.

[0153] These radical initiators are usually used in an amount of 0.001 part by mass or more, preferably 0.003 part by mass or more, and more preferably 0.05 part by mass or more, based on 100 parts by mass of the ethylene-α-olefin copolymer (B0), so that the radical reaction can occur sufficiently. On the other hand, although the upper limit of the amount of the radical initiator is not particularly limited as long as the effects of the present invention are not impaired, the amount is, for example, 5 parts by mass or less based on 100 parts by mass of the ethylene-α-olefin copolymer (B0). Here, in one aspect of the present invention, the radical initiator is usually used in an amount of 0.001 to 1 part by mass, preferably 0.003 to 0.5 part by mass, and more preferably 0.05 to 0.3 part by mass, based on 100 parts by mass of the ethylene-α-olefin copolymer (B0). However, depending on the type of the ethylene-α-olefin copolymer (B0), the amount of the radical initiator does not prevent the amount from exceeding 1 part by mass based on 100 parts by mass of the ethylene-α-olefin copolymer (B0), and for example, 1 to 3 parts by mass may be preferable in some cases.

[0154] The reaction temperature in the graft reaction using the radical initiator as described above or the graft reaction carried out without using a radical initiator is usually set in the range of 60 to 350°C, preferably 120 to 300°C.

[0155] [Crosslinking agent (C)] The crosslinking agent (C) crosslinks the (meth)acrylic resin (A) to further enhance the adhesiveness of the pressure-sensitive adhesive composition used in the present invention.

[0156] Examples of the crosslinking agent (C) include epoxy compounds such as sorbitol polyglycidyl ether, polyglycerol polyglycidyl ether, pentaerythritol polyglycidyl ether, diglycerol polyglycidyl ether, glycerol polyglycidyl ether, neopentyl glycol diglycidyl ether, and resorcin diglycidyl ether; isocyanate compounds such as tetramethylene diisocyanate, hexamethylene diisocyanate, toluene diisocyanate 3-adduct of trimethylolpropane, and polyisocyanate; aziridine compounds such as trimethylolpropane-tri-β-aziridinylpropionate, tetramethylolmethane-tri-β-aziridinylpropionate, N,N'-diphenylmethane-4,4'-bis(1-aziridinecarboxamide), N,N'-hexamethylene-1,6-bis(1-aziridinecarboxamide), N,N'-toluene-2,4-bis(1-aziridinecarboxamide), and trimethylolpropane-tri-β-(2-methylaziridine)propionate; and melamine compounds such as hexamethoxymethylol melamine. Here, the epoxy compound usually has two or more epoxy groups, the isocyanate compound usually has two or more isocyanate groups (groups represented by -N=C=O), and the aziridine compound usually has two or more aziridine groups. In one of the preferred and exemplary embodiments of the present invention, the crosslinking agent (C) is an isocyanate compound. The crosslinking agent (C) may be used alone or in combination of two or more.

[0157] The crosslinking agent (C) is preferably blended to such an extent that the number of functional groups capable of bonding to the (meth)acrylic resin (A) in the crosslinking agent (C) (when the crosslinking agent (C) contains a blocked isocyanate, it includes the number of functional groups generated by the dissociation of the blocking agent) does not exceed the number of functional groups of the (meth)acrylic resin (A). However, when a new functional group is generated by the crosslinking reaction or when the progress of the crosslinking reaction is slow, a larger amount may be blended.

[0158] [Content of Each Component] When the total of the content of the above (meth)acrylic resin (A), the content of the above graft-modified ethylene·α-olefin copolymer (B), and the content of the above crosslinking agent (C) is 100% by mass, the amount of the (meth)acrylic resin (A) is 47% by mass or more and 99% by mass or less, the amount of the graft-modified ethylene·α-olefin copolymer (B) is 0.5% by mass or more and 50% by mass or less, it is preferable that the amount of the crosslinking agent (C) is 0.5% by mass or more and 5% by mass or less.

[0159] When the content of the above (meth)acrylic resin (A) is a certain amount or more, for example, 47% by mass or more, a larger amount of the (meth)acrylic resin (A) will be contained in the pressure-sensitive adhesive composition. Since the crosslinking density of the pressure-sensitive adhesive composition becomes higher and the molecular weight becomes higher, it has excellent mechanical strength and is less likely to cause a decrease in adhesiveness. From this point, the content of the above (meth)acrylic resin (A) is more preferably 55% by mass or more, and even more preferably 60% by mass or more.

[0160] When the content of the above (meth)acrylic resin (A) is a certain amount or less, for example, 99% by mass or less, a larger amount of the graft-modified ethylene·α-olefin copolymer (B) and the crosslinking agent (C) will be contained in the pressure-sensitive adhesive composition. Therefore, the low-temperature flexibility, moisture resistance, and adhesiveness of the pressure-sensitive adhesive composition can be further enhanced. From this point, the content of the above (meth)acrylic resin (A) is more preferably 97% by mass or less, and even more preferably 95% by mass or less. However, in order to surely obtain both sufficiently high low-temperature flexibility and sufficiently high adhesiveness, the content of the above (meth)acrylic resin (A) may be preferably, for example, 85% by mass or less or 80% by mass or less.

[0161] From the above viewpoints, the content of the above (meth)acrylic resin (A) is more preferably 55% by mass or more and 97% by mass or less, and even more preferably 60% by mass or more and 95% by mass or less.

[0162] When the content of the graft-modified ethylene-α-olefin copolymer (B) is 0.5% by mass or more, the low-temperature flexibility and moisture resistance of the pressure-sensitive adhesive composition can be further enhanced. From this aspect, the content of the graft-modified ethylene-α-olefin copolymer (B) is more preferably 1% by mass or more, and even more preferably 3% by mass or more. However, in order to surely obtain both sufficiently high low-temperature flexibility and sufficiently high adhesiveness, the content of the graft-modified ethylene-α-olefin copolymer (B) may be, for example, preferably 15% by mass or more or 20% by mass or more.

[0163] When the content of the graft-modified ethylene-α-olefin copolymer (B) is 50% by mass or less, the adhesiveness of the pressure-sensitive adhesive composition can be further enhanced. From this aspect, the content of the graft-modified ethylene-α-olefin copolymer (B) is more preferably 40% by mass or less, and even more preferably 35% by mass or less.

[0164] From the above viewpoints, the content of the graft-modified ethylene-α-olefin copolymer (B) is more preferably 1% by mass or more and 40% by mass or less, and even more preferably 3% by mass or more and 35% by mass or less.

[0165] When the content of the crosslinking agent (C) is 0.5% by mass or more, the pressure-sensitive adhesive composition is likely to aggregate, and so-called glue residue, in which the pressure-sensitive adhesive composition remains on the surface of the adherend after pressure bonding, hardly occurs. From this aspect, the content of the crosslinking agent (C) is more preferably 0.7% by mass or more, and even more preferably 1% by mass or more.

[0166] When the content of the crosslinking agent (C) is 5% by mass or less, a larger amount of the (meth)acrylic resin (A) is contained in the pressure-sensitive adhesive composition, and the crosslinking density of the pressure-sensitive adhesive composition becomes higher and the molecular weight becomes higher, so that it has excellent mechanical strength and hardly causes a decrease in adhesiveness. From this aspect, the content of the crosslinking agent (C) is more preferably 3% by mass or less, and even more preferably 2.5% by mass or less. From the above viewpoints, the content of the crosslinking agent (C) is more preferably 0.7% by mass or more and 3% by mass or less, and even more preferably 1% by mass or more and 2.5% by mass or less.

[0167] [Additive] In addition to the above (meth)acrylic resin (A), the graft-modified ethylene / α-olefin copolymer (B), and the crosslinking agent (C), the pressure-sensitive adhesive composition used in the present invention may contain, as an additive, at least one selected from an organic solvent, an antistatic agent, a silane coupling agent, an ultraviolet absorber, an antioxidant, a tackifier resin, a plasticizer, an antifoaming agent, a filler, a stabilizer, a softening agent, and a wettability modifier, as long as the effects of the present invention are not impaired.

[0168] [Method for producing pressure-sensitive adhesive composition] The pressure-sensitive adhesive composition used in the present invention can be prepared by mixing the above-described (meth)acrylic resin (A), graft-modified ethylene / α-olefin copolymer (B), and crosslinking agent (C) in a blending amount corresponding to the above-described content together with an arbitrarily used solvent. That is, the production method according to the present invention includes the above (meth)acrylic resin (A), the above graft-modified ethylene / α-olefin copolymer (B), the above crosslinking agent (C), and a step of mixing them (hereinafter referred to as "step (S1)"). By this step, a composition containing the (meth)acrylic resin (A), the graft-modified ethylene / α-olefin copolymer (B), and the crosslinking agent (C) is obtained. Here, when mixing, the mixture containing the (meth)acrylic resin (A), the graft-modified ethylene / α-olefin copolymer (B), and the crosslinking agent (C) may also contain a solvent. Further, the mixture may also contain the above additives. Examples of the above solvent include ethyl acetate, butyl acetate, benzene, toluene, xylene, cyclohexane, and methyl ethyl ketone.

[0169] Here, in a preferred and exemplary embodiment of the present invention, the graft-modified ethylene-α-olefin copolymer (B) is produced by the method (α) or method (β) described above in the "method for producing a graft-modified ethylene-α-olefin copolymer (B)". Therefore, the production method may further include a step of obtaining the graft-modified ethylene-α-olefin copolymer (B) by the method (α) or method (β) described above in the "method for producing a graft-modified ethylene-α-olefin copolymer (B)". The pressure-sensitive adhesive composition used in the present invention can be suitably used as a pressure-sensitive adhesive and can be used in various applications that require pressure sensitivity, such as pressure-sensitive processed products such as sheets, tapes, labels, and double-sided tapes, and sealing materials.

[0170] 〔Pressure-sensitive adhesive layer and pressure-sensitive adhesive sheet〕 <Pressure-sensitive adhesive layer> The pressure-sensitive adhesive layer according to the present invention is composed of the above pressure-sensitive adhesive composition and has a gel fraction of 40% by mass or more. The pressure-sensitive adhesive layer according to the present invention may be composed of an uncrosslinked pressure-sensitive adhesive composition as long as the effects of the present invention are not impaired, or may be composed of a crosslinked product of the above pressure-sensitive adhesive composition (that is, a crosslinked product of the above pressure-sensitive adhesive composition). In a typical embodiment of the present invention, the pressure-sensitive adhesive layer is composed of a crosslinked product of the above pressure-sensitive adhesive composition.

[0171] The gel fraction of the pressure-sensitive adhesive layer according to the present invention is 40% by mass or more, preferably 50% by mass or more. When the gel fraction is at least the lower limit value, there is a tendency to reduce the risk of paste oozing over time, which is preferable. In addition, when the gel fraction is at least the lower limit value, when the pressure-sensitive adhesive layer according to the present invention is used in an image display device such as a liquid crystal display or an input device such as a touch panel used in combination with such an image display device, there is also an advantage that the appearance of the image display device or the input device is less likely to deteriorate.

[0172] On the one hand, although the upper limit value of the gel fraction of the pressure-sensitive adhesive layer according to the present invention is not particularly limited, the gel fraction is usually 100% by mass or less, preferably 90% by mass or less, and more preferably 70% by mass or less.

[0173] Here, the gel fraction is considered to be an indication of the amount of low-molecular-weight components that can be contained in the pressure-sensitive adhesive layer, and when the pressure-sensitive adhesive layer is composed of a crosslinked product of the above pressure-sensitive adhesive composition, it can also be an indication of the degree of crosslinking (degree of curing).

[0174] The gel fraction is a process (SG1) of taking out an appropriate amount of sample from the pressure-sensitive adhesive layer, wrapping the sample with a 300-mesh wire mesh, immersing it in toluene adjusted to 23°C for 24 hours, and then drying it under vacuum at 80°C for 1 hour; a process (SG2) of calculating the ratio of the mass of the insoluble sample remaining in the wire mesh obtained after the process (SG1) to the mass of the sample before the toluene immersion used in the process (SG1), and calculating the percentage of the ratio as the gel fraction and can be determined by a method including this. Here, the pressure-sensitive adhesive layer used in the process (SG1) is usually a pressure-sensitive adhesive layer composed of a crosslinked product of the above pressure-sensitive adhesive composition.

[0175] Specifically, the gel fraction can be measured under the measurement conditions described in the examples below. The haze of the pressure-sensitive adhesive layer according to the present invention, measured in accordance with JIS K7136, is preferably 5.0% or less, more preferably 4.0% or less. When the haze is below the above upper limit value, excellent transparency and excellent appearance can be obtained, which is preferable. When the haze is below the above upper limit value, it is useful for applications such as image display devices where transparency is required. On the other hand, although the lower limit value of the haze of the pressure-sensitive adhesive layer according to the present invention is not particularly limited, theoretically it is 0%, and in practical use it may exceed 0.01%.

[0176] The haze can be measured under the measurement conditions described in the examples below. The total light transmittance of the pressure-sensitive adhesive layer according to the present invention, measured in accordance with JIS K7361, is preferably 80% or more, more preferably 85% or more. When the total light transmittance is equal to or higher than the lower limit value, excellent transparency and excellent appearance can be obtained, which is preferable. When the total light transmittance is equal to or higher than the lower limit value, it is useful for applications that require transparency, such as image display devices.

[0177] On the other hand, although the upper limit value of the total light transmittance of the pressure-sensitive adhesive layer according to the present invention is not particularly limited, it may be 95% or less in practical use. The total light transmittance can be measured under the measurement conditions described in the examples below. The thickness of the pressure-sensitive adhesive layer according to the present invention is usually 3 μm or more, preferably 5 μm or more, more preferably 10 μm or more, from the viewpoint of easy stabilization of adhesive physical properties. On the other hand, the thickness is usually 1000 μm or less, preferably 500 μm or less, more preferably 200 μm or less, from the viewpoint of easy drying effectively.

[0178] When the thickness of the pressure-sensitive adhesive layer is formed by applying the above pressure-sensitive adhesive composition, it can be adjusted by the coating thickness and the solid content concentration of the coating solution. The pressure-sensitive adhesive layer can be formed from the above pressure-sensitive adhesive composition, that is, the composition obtained in the step (S1) described above in the "method for producing a pressure-sensitive adhesive composition". Here, the formation can be performed by applying the above pressure-sensitive adhesive composition. In this case, the pressure-sensitive adhesive layer can be produced, for example, by forming the above pressure-sensitive adhesive composition into a film shape and removing the solvent. Here, the removal of the solvent can be performed by heating or the like. More specifically, the pressure-sensitive adhesive composition according to the present invention is applied onto a separator or a substrate by a known method such as a roll coater method, a reverse roll coater method, a gravure roll method, a bar coating method, a comma coater method, and a die coater method, and the applied pressure-sensitive adhesive composition is dried to produce the pressure-sensitive adhesive layer according to the present invention.

[0179] Specific formation conditions of the adhesive layer are as follows, for example. The above-mentioned pressure-sensitive adhesive composition is applied onto a separator or a substrate, and is usually dried at 60 to 120 °C, preferably 70 to 110 °C, usually for 1 to 15 minutes, preferably for 2 to 10 minutes, to form a coating film. Subsequently, when applied onto a separator, a substrate or a separator is laminated onto the coating film on the side without the separator, and when applied onto a substrate, a separator is laminated onto the coating film. Subsequently, it is cured (aged) under an environment of usually 1 day or more, preferably 3 to 10 days, usually 5 to 60 °C, preferably 15 to 50 °C, and usually 30 to 70% RH, preferably 40 to 70% RH. When crosslinking is performed under the above-mentioned aging conditions, a crosslinked product (network polymer) can be efficiently formed. In the case of a coating film sandwiched by separators, after aging, one of the separators is peeled off, and a substrate is laminated onto the exposed adhesive layer.

[0180] <Adhesive sheet> The adhesive sheet of the present invention has the above-mentioned adhesive layer. The thickness, gel fraction, haze, and total light transmittance of the adhesive layer constituting the adhesive sheet of the present invention are as described above in the "adhesive layer".

[0181] Examples of the adhesive sheet include a double-sided adhesive sheet having only the above-mentioned adhesive layer, a double-sided adhesive sheet having a substrate and the above-mentioned adhesive layers formed on both sides of the substrate, a single-sided adhesive sheet having a substrate and the above-mentioned adhesive layer formed on one side of the substrate, and an adhesive sheet to which a separator subjected to a peeling treatment is attached to a surface not in contact with other layers of the adhesive layer in these adhesive sheets.

[0182] In other words, the adhesive sheet of the present invention may be an adhesive sheet consisting only of the above-mentioned adhesive layer, an adhesive sheet having the above-mentioned adhesive layer and one or more substrate layers, wherein the one or more substrate layers are in direct contact with one side or both sides of the above-mentioned adhesive layer. It may be an adhesive sheet having the above adhesive layer and one or more release layers, wherein the one or more release layers are in direct contact with the adhesive layer on one or both sides of the adhesive layer. It may be an adhesive sheet having the above adhesive layer, a base material layer, and a release layer, wherein the base material layer is on one side of the adhesive layer, and the release layer is in direct contact with the adhesive layer on the surface of the adhesive layer opposite to the base material layer. Here, the release layer is a layer made of the separator.

[0183] Examples of the base material and the separator include plastic films such as polyester (e.g., polyethylene terephthalate, polyethylene naphthalate, etc.), polyethylene, polypropylene, polycarbonate, polymethyl methacrylate, acrylonitrile-butadiene-styrene copolymer, ethylene-vinyl acetate copolymer, polyamide, polyurethane, and polyvinyl chloride; woven fabrics, non-woven fabrics; paper, glass, etc. The surfaces of the base material and the separator may each be subjected to a release treatment.

[0184] The adhesive layer constituting the adhesive sheet of the present invention can be formed from the above adhesive composition, that is, the composition obtained in step (S1) described above in the "method for producing an adhesive composition". That is, the method for producing the adhesive sheet of the present invention is Step (S1) described above in the "method for producing an adhesive composition", and Step (S2) of forming an adhesive layer from the composition obtained in step (S1) can be said to be included.

[0185] Here, step (S2) can be carried out by applying the above adhesive composition (that is, the composition obtained in step (S1)). In this case, the adhesive layer can be produced, for example, by forming the above adhesive composition into a film shape on a separator or a base material and removing the solvent. Here, the removal of the solvent can be carried out by heating or the like.

[0186] For example, the pressure-sensitive adhesive sheet consisting only of the above pressure-sensitive adhesive layer can be obtained by a production method including a step of applying the pressure-sensitive adhesive composition (i.e., the composition obtained in the step (S1)) to a separator and forming it into a film shape, and then removing the solvent to obtain an intermediate sheet composed of a pressure-sensitive adhesive layer and a release layer, and a step of peeling the release layer from the intermediate sheet obtained by the above step.

[0187] Further, the pressure-sensitive adhesive sheet having the above pressure-sensitive adhesive layer and a base material layer (i.e., the pressure-sensitive adhesive sheet having the above pressure-sensitive adhesive layer and one or more base material layers, and the one or more base material layers being directly in contact with one side or both sides of the above pressure-sensitive adhesive layer) can be obtained by a production method including a step of applying the pressure-sensitive adhesive composition (i.e., the composition obtained in the step (S1)) to a base material and forming it into a film shape, and then removing the solvent. Here, the pressure-sensitive adhesive sheet having a first base material layer, the above pressure-sensitive adhesive layer, and a second base material layer in this order can be obtained by a production method including a step of applying the pressure-sensitive adhesive composition (i.e., the composition obtained in the step (S1)) to the first base material and forming it into a film shape, and then removing the solvent to obtain an intermediate sheet composed of a pressure-sensitive adhesive layer and the first base material layer, and a step of attaching the second base material to the surface where the pressure-sensitive adhesive layer exists in the intermediate sheet obtained by the above step.

[0188] Also, the pressure-sensitive adhesive sheet having the above pressure-sensitive adhesive layer and a release layer (i.e., the pressure-sensitive adhesive sheet having the above pressure-sensitive adhesive layer and one or more release layers, and the one or more release layers being directly in contact with one side or both sides of the above pressure-sensitive adhesive layer) can be obtained by a production method including a step of applying the pressure-sensitive adhesive composition (i.e., the composition obtained in the step (S1)) to a separator and forming it into a film shape, and then removing the solvent. Here, the pressure-sensitive adhesive sheet having a first release layer, the above pressure-sensitive adhesive layer, and a second release layer in this order can be obtained by a production method including a step of applying the pressure-sensitive adhesive composition (i.e., the composition obtained in the step (S1)) to the first separator and forming it into a film shape, and then removing the solvent to obtain an intermediate sheet composed of a pressure-sensitive adhesive layer and the first release layer, and a step of attaching the second separator to the surface where the pressure-sensitive adhesive layer exists in the intermediate sheet obtained by the above step.

[0189] Further, an adhesive sheet having a base material layer, the adhesive layer, and the release layer in this order (that is, having the adhesive layer, the base material layer, and the release layer, with the base material layer on one side of the adhesive layer and the release layer on the surface of the adhesive layer opposite to the base material layer, each directly contacting the adhesive layer) can be obtained by a production method including a step of applying the pressure-sensitive adhesive composition (that is, the composition obtained in the step (S1)) to a separator and forming it into a film shape, removing the solvent to obtain an intermediate sheet composed of the adhesive layer and the release layer, and a step of attaching a base material to the surface of the intermediate sheet where the adhesive layer exists obtained by the above step. Such an adhesive sheet may be obtained by a production method including a step of applying the pressure-sensitive adhesive composition (that is, the composition obtained in the step (S1)) to a base material and forming it into a film shape, removing the solvent to obtain an intermediate sheet composed of the adhesive layer and the base material, and a step of attaching a separator to the surface of the intermediate sheet where the adhesive layer exists obtained by the above step. More specific application methods of the pressure-sensitive adhesive composition and specific formation conditions of the adhesive layer are as described above in the "adhesive layer".

[0190] <Use of the Adhesive Sheet>

[0191] The adhesive sheet of the present invention has good adhesiveness to adherends such as polyolefins such as polypropylene and polyethylene, resins other than polyolefins, and glass, and can be used for various members for displays, members for touch panels, members for automobiles, members for aircraft, members for ships, members for electrical appliances, members for building materials, electronic devices, conductive substrates, and the like.

[0192] Touch panels are mounted on in-vehicle devices such as car navigation devices, in addition to smartphones and tablet computers. Examples of electronic devices include organic EL devices, solar cells, and sensor devices.

[0193] Here, in one of the preferred embodiments of the present invention, the pressure-sensitive adhesive sheet of the present invention is used for forming a laminate. That is, the present invention provides a laminate having the above pressure-sensitive adhesive sheet. Here, the laminate can also be regarded as having the above pressure-sensitive adhesive layer.

[0194] The laminate can include adherends on both sides of the pressure-sensitive adhesive sheet. When the pressure-sensitive adhesive sheet is a double-sided pressure-sensitive adhesive sheet, it is preferable to bond two adherends with the pressure-sensitive adhesive sheet before post-curing, and then form the laminate by post-curing the pressure-sensitive adhesive layer. For example, the laminate Prepare a pressure-sensitive adhesive sheet having a first release layer, the above pressure-sensitive adhesive layer, and a second release layer in this order, peel off the first release layer constituting the pressure-sensitive adhesive sheet to expose the pressure-sensitive adhesive layer, and bring a first adherend into contact with the exposed surface of the pressure-sensitive adhesive layer (that is, the surface where the first release layer was present), thereby obtaining a first laminate composed of the pressure-sensitive adhesive layer and the first adherend; In the first laminate, peel off the second release layer constituting the pressure-sensitive adhesive sheet to expose the pressure-sensitive adhesive layer, and bring a second adherend into contact with the exposed surface of the pressure-sensitive adhesive layer (that is, the surface where the second release layer was present), thereby obtaining a second laminate having the first adherend, the pressure-sensitive adhesive layer, and the second adherend in this order can be obtained by a manufacturing method including. Further, the laminate Prepare a pressure-sensitive adhesive sheet having a first release layer, the above pressure-sensitive adhesive layer, and a second release layer in this order, peel off the first release layer and the second release layer constituting the pressure-sensitive adhesive sheet to expose both surfaces of the pressure-sensitive adhesive layer, bring a first adherend into contact with the surface where the first release layer was present among the exposed surfaces of the pressure-sensitive adhesive layer, and bring a second adherend into contact with the surface where the second release layer was present among the exposed surfaces of the pressure-sensitive adhesive layer, thereby obtaining a laminate having the first adherend, the pressure-sensitive adhesive layer, and the second adherend in this order may be obtained by a manufacturing method including.

[0195] Here, the adherend is more preferably a base material and an optical member, and particularly preferably a polycarbonate film, a polarizing plate, a transparent film, a transparent resin, or glass. Here, the base material that can be an adherend may be a base material of the same material as the base material constituting the pressure-sensitive adhesive sheet, or may be a base material of a different material.

[0196] The pressure-sensitive adhesive sheet of the present invention is preferably used for bonding to a base material, and preferably used for bonding a base material and another optical member. In addition, the pressure-sensitive adhesive sheet of the present invention may be used for bonding to a polarizing plate.

[0197] Examples of the optical member included in the laminate include components in optical products such as touch panels and image display devices, and anti-scattering films bonded to the outermost cover lens. Examples of the components of the touch panel include an ITO film in which an ITO film is provided on a transparent resin film, ITO glass in which an ITO film is provided on the surface of a glass plate, a transparent conductive film in which a conductive polymer is coated on a transparent resin film, a hard coat film, and a fingerprint-resistant film. Examples of the components of the image display device include an anti-reflection film, an alignment film, a polarizing film, a retardation film, and a brightness enhancement film used in a liquid crystal display device.

[0198] Examples of the materials used for these members include glass, polycarbonate, polyethylene terephthalate, polymethyl methacrylate, polyethylene naphthalate, cycloolefin polymer, triacetyl cellulose, polyimide, and cellulose acylate.

[0199] As described above, the laminate can be obtained by a manufacturing method including a step of laminating an adherend on at least one surface side of the pressure-sensitive adhesive sheet and a step of post-curing the pressure-sensitive adhesive layer. As described above, since the adhesive sheet of the present invention can have an optical member as an adherend, it can be said that the adhesive sheet of the present invention is used for forming an optical member. That is, the present invention provides an optical member having the above adhesive sheet. Here, the optical member can also be regarded as having the above adhesive layer.

[0200] In one of the preferred and exemplary embodiments of the present invention, the optical member is an optical member having at least the above adhesive sheet and a substrate, the substrate is provided with metal wiring (for example, metal mesh wiring, silver nanowires, etc.) on at least one side, and the adhesive layer of the present invention (the adhesive layer formed by the adhesive composition of the present invention) is adhered to the surface of the substrate on the side having the metal wiring, and is not particularly limited in other respects. Note that the adhesive sheet of the present invention may be provided with a separator (release layer) on the adhesive surface until use, but since the adhesive sheet in the optical member of the present invention is the adhesive sheet at the time of use, it does not have a separator (release layer).

[0201] From the viewpoint of obtaining a more excellent corrosion prevention effect, it is preferable that the optical member has the adhesive layer on the side opposite to the side of the substrate having the metal wiring, and it is more preferable that the adhesive layer is adhered to the surface on the side opposite to the side of the substrate having the metal wiring.

[0202] The material constituting the metal wiring is not particularly limited. For example, metals such as titanium, silicon, niobium, indium, zinc, tin, gold, silver, copper, aluminum, cobalt, chromium, nickel, lead, iron, palladium, platinum, tungsten, zirconium, tantalum, and hafnium can be mentioned. Furthermore, those containing two or more of these metals and alloys mainly composed of these metals can also be mentioned. Among them, from the viewpoint of conductivity, gold, silver, and copper are preferable, and from the viewpoints of conductivity and cost, silver and copper are more preferable. That is, the above metal wiring is preferably silver wiring and / or copper wiring, particularly copper mesh wiring, silver mesh wiring, or silver nanowires. Also, an oxide film or a metal coating film may be provided on the metal wiring for the purpose of more advanced rust prevention. Note that the material constituting the metal wiring of the touch panel described later is the same.

[0203] An optical member refers to a member having optical characteristics (e.g., polarization, photo-refractivity, light scattering, light reflection, light transmittance, light absorption, photo-diffraction, optical rotation, visibility, etc.). The substrate constituting the optical member is not particularly limited, and examples include substrates constituting devices (optical devices) such as display devices (image display devices) and input devices, or substrates used in these devices. Examples include polarizing plates, wave plates, retardation plates, optical compensation films, brightness enhancement films, light guide plates, reflection films, anti-reflection films, hard coat films (films obtained by subjecting at least one surface of a plastic film such as a PET film to a hard coat treatment), transparent conductive films (e.g., plastic films having an ITO layer on the surface (preferably ITO films such as PET-ITO, polycarbonate, cycloolefin polymer, etc.)), design films, decorative films, surface protection plates, prisms, lenses, color filters, transparent substrates (glass substrates such as glass sensors, glass display panels (LCDs, etc.), glass plates with transparent electrodes), and further substrates on which these are laminated (which may be collectively referred to as "functional films"). Further, these films may have a metal nanowire layer, a conductive polymer layer, or the like. Further, fine metal wires may be screen-printed on these films. Note that the above "plate" and "film" include forms such as plate-like, film-like, and sheet-like. For example, "polarizing film" includes "polarizing plate" and "polarizing sheet", etc. Further, "film" includes film sensors, etc.

[0204] In particular, the pressure-sensitive adhesive sheet of the present invention is preferably used for an optical member having a transparent conductive film (metal mesh film, silver nanowire film) in which the metal wiring is a metal mesh wiring or silver nanowires, particularly a metal mesh film. Silver and copper are metals that are prone to ion migration. In particular, silver and copper in the form of metal mesh wiring or silver nanowires are prone to ion migration, and malfunctions are likely to occur due to short circuits caused by metal ions penetrating into the adhesive layer. Since the pressure-sensitive adhesive sheet of the present invention has a low dielectric constant and excellent stress relaxation properties, it is filled without leaving bubbles at steps due to metal wiring or the like, and silver and copper are less likely to malfunction due to ion migration. The same applies to the metal mesh film and silver nanowire film constituting the touch panel described later.

[0205] Examples of the display device (image display device) include a liquid crystal display device, an organic EL (electroluminescence) display device, a PDP (plasma display panel), and electronic paper. Examples of the input device include a touch panel. When the pressure-sensitive adhesive sheet of the present invention is used in the manufacture of a touch panel, the touch panel is a touch panel having at least the pressure-sensitive adhesive sheet and a substrate. The substrate is provided with metal wiring (for example, metal mesh wiring, silver nanowires, etc.) on one side, and it is sufficient that the adhesive layer is adhered to the surface of the substrate having the metal wiring, and there are no other particular limitations. Note that since the pressure-sensitive adhesive sheet in the touch panel is the pressure-sensitive adhesive sheet during use, it does not have a separator.

[0206] The substrate constituting the optical member is not particularly limited. Examples include substrates made of glass, acrylic resin, polycarbonate, polyethylene terephthalate, cycloolefin polymer, metal thin film, etc. (for example, sheet-like, film-like, plate-like substrates, etc.). Note that the "optical member" in the present invention includes members (design films, decorative films, surface protection films, etc.) that play a role in decoration and protection while maintaining the visibility of the display device and the input device as described above.

[0207] If the pressure-sensitive adhesive sheet of the present invention is a pressure-sensitive adhesive sheet with a substrate, and the pressure-sensitive adhesive sheet constitutes a member having optical characteristics, the substrate can be regarded as the same as the substrate, and it can be said that the pressure-sensitive adhesive sheet is also an optical member of the present invention.

[0208] In a preferred and exemplary embodiment of the present invention, the pressure-sensitive adhesive sheet of the present invention is used in the manufacture of a touch panel type input / output device or an image display device. That is, it can be said that the present invention provides a touch panel type input / output device or an image display device having the pressure-sensitive adhesive sheet.

Example

[0209] Hereinafter, the present invention will be described more specifically based on examples, but the present invention is not limited to these examples. In the following examples and comparative examples, each physical property was measured or evaluated by the following methods.

[0210] 〔Weight average molecular weight (Mw) and molecular weight distribution (Mw / Mn)〕 Determined by the following high-speed GPC measuring device. Measuring device: HLC8320GPC manufactured by Tosoh Corporation Mobile phase: THF (manufactured by Wako Pure Chemical Industries, Ltd., stabilizer-free, grade for liquid chromatography) Column: Two TSKgel Super Multipore HZ-M columns manufactured by Tosoh Corporation were connected in series. Sample concentration: 5 mg / mL Mobile phase flow rate: 0.35 mL / min Measurement temperature: 40 °C Standard sample for calibration curve: PStQuick MP-M manufactured by Tosoh Corporation

[0211] 〔Kinematic viscosity〕 Based on ASTM D 445, measurement was carried out using a fully automatic viscometer CAV-4 manufactured by CANNON INSTRUMENT COMPANY. The above measurement was carried out at 100 °C unless otherwise specified.

[0212] 〔Composition〕 The content ratios of each structural unit (ethylene and α-olefin) in the ethylene-α-olefin copolymer were 13 measured by 13C-NMR. Here, the NMR measurement was performed using an ECP500 type nuclear magnetic resonance apparatus manufactured by JEOL Ltd., with an ortho-dichlorobenzene / heavy benzene (80 / 20 vol%) mixed solvent as the solvent, a sample concentration of 55 mg / 0.6 mL, a measurement temperature of 120 °C, and 13 13C (125 MHz) as the observed nucleus, a single pulse proton decoupling as the sequence, a pulse width of 4.7 μs (45° pulse), a repetition time of 5.5 s, an integration number of 10,000 times or more, and a chemical shift reference value of 27.50 ppm. The ethylene content was 13 determined from the 13C-NMR spectrum based on the reports of "Polymer Analysis Handbook" (published by Asakura Shoten, P163 - 170), G. J. Ray (Macromolecules, 10, 773 (1977)), J. C. Randall (Macromolecules, 15, 353 (1982)), K. Kimura (Polymer, 25, 4418 (1984)), etc.

[0213] [Melting point] It was measured using an X-DSC-7000 manufactured by Seiko Instruments Inc. Approximately 8 mg of the sample was placed in a simple sealable aluminum sample pan and arranged in the DSC cell. The DSC cell was heated from room temperature to 150 °C at 10 °C / min under a nitrogen atmosphere, then held at 150 °C for 5 minutes, and then cooled at 10 °C / min until the DSC cell was cooled to -100 °C (cooling process). Then, after holding at -100 °C for 5 minutes, it was heated from -100 °C to 150 °C at 10 °C / min. The temperature at which the enthalpy curve (DSC curve) obtained during the heating process shows a maximum value (however, a minimum value when the heat flow (heat flux) associated with endotherm is taken in the negative direction) was defined as the melting point, and the total sum of the endothermic amount associated with melting was defined as the heat of fusion. In this enthalpy curve (DSC curve), when no peak was observed or the value of the observed heat of fusion was 1 J / g or less, the melting point (Tm) was considered not to be observed. The method for determining the melting point and the heat of fusion was carried out based on JIS K7121.

[0214] [(Meth)acrylic resin (A)] [Production Example A1] Synthesis of (meth)acrylic resin (A-1) Into a temperature-adjustable reactor equipped with a stirrer, 350 parts by mass of ethyl acetate as a polymerization solvent and 40 parts by mass of toluene were charged, purged with nitrogen, and the temperature was raised to 75°C. Then, to the resulting mixture of ethyl acetate and toluene, a mixture of 316 parts by mass of n-butyl acrylate, 43 parts by mass of ethyl acrylate, 50 parts by mass of vinyl acetate, 9 parts by mass of acrylic acid, 2 parts by mass of hydroxyethyl acrylate, and 2 parts by mass of benzoyl peroxide as a polymerization initiator was continuously added, and then reacted for 5 hours. Five hours after the addition was completed, the resulting reaction mixture was diluted with 120 parts by mass of toluene to obtain an ethyl acetate / toluene solution containing a (meth)acrylic resin (solid content: 45% by mass; mass ratio of ethyl acetate to toluene: 69 / 31).

[0215] Here, the (meth)acrylic resin obtained in this production example is designated as (meth)acrylic resin (A-1). The peak temperature of the loss tangent (tanδ) due to the glass transition temperature of the (meth)acrylic resin (A-1) obtained by volatilizing the solvent from the resulting ethyl acetate / toluene solution and measuring the temperature dependence of the dynamic viscoelasticity (frequency 1 Hz, -100 to 200°C) was -47°C.

[0216] When the composition of the (meth)acrylic resin (A-1) was quantified by pyrolysis gas chromatography-mass spectrometry (pyrolysis GC-MS), the content of the structural unit derived from (meth)acrylate having an alkyl group with 1 to 12 carbon atoms was 80 mol%, and the content of the structural unit derived from (meth)acrylate containing a hydroxyl group was 0.5 mol%. Here, the quantification by pyrolysis GC-MS was performed under the following conditions.

[0217] Pyrolysis apparatus: JAI JHP-5 manufactured by Nippon Analytical Industry Co., Ltd. Pyrolysis temperature: 590°C GC apparatus: 6890N manufactured by Agilent Column: DB-5MS manufactured by Agilent Column temperature: 40 °C Column flow rate: 0.9 mL / min (mobile phase: helium) MS device: JMS-Q1000GC manufactured by JEOL

[0218] [Ethylene·α-olefin copolymer (X)] [Production Example X1] Synthesis of ethylene·α-olefin copolymer (X-1) 760 mL of heptane and 120 g of propylene were charged into a 2 L stainless steel autoclave fully purged with nitrogen. After raising the temperature inside the system to 150 °C, hydrogen 0.85 MPa and ethylene 0.19 MPa were supplied to make the total pressure 3 MPa-G. Next, 0.4 mmol of triisobutylaluminum, 5 [methylphenylmethylene(η 5 -cyclopentadienyl)(η

[0219] -2,7-di-tert-butylfluorenyl)]zirconium dichloride 0.0002 mmol, and N,N-dimethylanilinium tetrakis(pentafluorophenyl)borate 0.002 mmol were injected with nitrogen, and the polymerization was started by setting the stirring rotation speed to 400 rpm. Then, by continuously supplying only ethylene, the total pressure was maintained at 3 MPa-G, and the polymerization was carried out at 150 °C for 5 minutes. After stopping the polymerization by adding a small amount of ethanol to the system, unreacted ethylene, propylene, and hydrogen were purged. The obtained polymerization solution was washed 3 times with 1000 mL of 0.2 mol / L hydrochloric acid and then 3 times with 1000 mL of distilled water, dried over magnesium sulfate, and the solvent was distilled off under reduced pressure to obtain a crude ethylene·propylene copolymer.Into a 1 L stainless steel autoclave, 100 mL of a hexane solution of 0.5 mass% Pd / alumina catalyst and 500 mL of a 30 mass% hexane solution of the obtained crude ethylene·α-olefin copolymer were added. After sealing the autoclave, nitrogen substitution was carried out. Then, while stirring, the temperature was raised to 140 °C. After replacing the system with hydrogen, the pressure was increased to 1.5 MPa with hydrogen and a hydrogenation reaction was carried out for 15 minutes. After filtering the reaction solution to separate the hydrogenation catalyst by filtration, the solvent was distilled off under reduced pressure from the obtained filtrate, and drying was carried out at 80 °C under reduced pressure for 24 hours to obtain an ethylene·propylene copolymer.

[0220] Here, the ethylene·propylene copolymer obtained in this production example is designated as ethylene·α-olefin copolymer (X-1). The obtained ethylene·α-olefin copolymer (X-1) had a weight average molecular weight (Mw) of 5100, a molecular weight distribution (Mw / Mn) of 1.7, a kinematic viscosity at 100 °C of 150 mm 2 / s, an ethylene content of 48 mol%, and no observed melting point.

[0221] [Production Example X2] Synthesis of ethylene·α-olefin copolymer (X-2) 760 mL of heptane and 120 g of propylene were charged into a 2 L stainless steel autoclave that had been sufficiently purged with nitrogen. After raising the temperature inside the system to 150 °C, the total pressure was set to 3 MPa-G by supplying 0.85 MPa of hydrogen and 0.19 MPa of ethylene. Next, 0.4 mmol of triisobutylaluminum, [diphenylmethylene(η 5 -3-n-butylcyclopentadienyl)(η 50.0002 mmol of [(2,7-di-tert-butylfluorenyl)]zirconium dichloride and 0.002 mmol of N,N-dimethylanilinium tetrakis(pentafluorophenyl)borate were pressured into nitrogen, and polymerization was initiated by setting the stirring speed to 400 rpm. Then, only ethylene was continuously supplied to maintain the total pressure at 3 MPa-G, and polymerization was carried out at 150 °C for 5 minutes. Polymerization was stopped by adding a small amount of ethanol to the system, and unreacted ethylene, propylene, and hydrogen were purged. The obtained polymerization solution was washed three times with 1000 mL of 0.2 mol / L hydrochloric acid and then three times with 1000 mL of distilled water, dried over magnesium sulfate, and the solvent was distilled off under reduced pressure to obtain a crude ethylene-propylene copolymer.

[0222] Into a 1 L stainless steel autoclave, 100 mL of a hexane solution of a 0.5 mass% Pd / alumina catalyst and 500 mL of a 30 mass% hexane solution of the obtained crude ethylene-α-olefin copolymer were added. After sealing the autoclave, nitrogen substitution was performed. Then, while stirring, the temperature was raised to 140 °C, the system was hydrogen-substituted, and the pressure was increased to 1.5 MPa with hydrogen and a hydrogenation reaction was carried out for 15 minutes. After filtering the reaction solution to separate the hydrogenated catalyst, the solvent was distilled off under reduced pressure from the obtained filtrate, and drying was carried out at 80 °C under reduced pressure for 24 hours to obtain an ethylene-propylene copolymer.

[0223] Here, the ethylene-propylene copolymer obtained in this production example is designated as ethylene-α-olefin copolymer (X-2). The obtained ethylene-α-olefin copolymer (X-2) had a weight average molecular weight (Mw) of 4800, a molecular weight distribution (Mw / Mn) of 1.7, a kinematic viscosity at 100 °C of 150 mm 2 / s, an ethylene content of 49 mol%, and no observed melting point.

[0224] [Production Example X3] Synthesis of ethylene-α-olefin copolymer (X-3) Into a 2-L continuous polymerization reactor with a stirrer blade that had been sufficiently purged with nitrogen, 1 L of dehydrated and purified hexane was placed. Then, a hexane solution of ethylaluminum sesquichloride (Al(C2H5) 1.5 ·Cl 1.5 ) prepared at 96 mmol / L was continuously fed at a rate of 500 mL / h for 1 hour. After that, as a catalyst, a hexane solution of VO(OC2H5)Cl2 adjusted to 16 mmol / L was continuously fed at a rate of 500 mL / h, and hexane was continuously fed at a rate of 500 mL / h. On the other hand, from the upper part of the reactor, the polymerization solution was continuously withdrawn so that the volume of the polymerization solution in the reactor always remained at 1 L.

[0225] Next, using a bubbling tube, ethylene gas was fed at a rate of 47 L / h, propylene gas was fed at a rate of 47 L / h, and hydrogen gas was fed at a rate of 20 L / h. The copolymerization reaction was carried out at 35 °C by circulating a refrigerant through a jacket attached outside the reactor. As a result, a polymerization solution containing an ethylene-propylene copolymer was obtained.

[0226] The obtained polymerization solution was washed three times with 500 mL of 0.2 mol / L hydrochloric acid per 1 L of the polymerization solution, and then washed three times with 500 mL of distilled water per 1 L of the polymerization solution. After drying with magnesium sulfate, the solvent was distilled off under reduced pressure. The obtained viscous liquid was dried at 130 °C under reduced pressure for 24 hours to obtain an ethylene-propylene copolymer.

[0227] Here, the ethylene-propylene copolymer obtained in this production example is designated as an ethylene-α-olefin copolymer (X-3). The obtained ethylene-α-olefin copolymer (X-3) had a weight-average molecular weight (Mw) of 14,000, a molecular weight distribution (Mw / Mn) of 2.0, a kinematic viscosity at 100 °C of 2100 mm 2 / s, an ethylene content of 55 mol%, and no observed melting point.

[0228] The data of the obtained ethylene·α-olefin copolymers (X-1) to (X-3) are shown below. In the following Production Examples B1, B2, and B3, the ethylene·α-olefin copolymers (X-1), (X-2), and (X-3) were used as the ethylene·α-olefin copolymer (B0), respectively.

[0229] [Table 1]

[0230] [Graft-modified ethylene·α-olefin copolymer (B)] [Production Example B1] Synthesis of graft-modified ethylene·α-olefin copolymer (B-1) Using the ethylene·α-olefin copolymer (X-1) as the raw material ethylene·α-olefin copolymer (ethylene·α-olefin copolymer (B0)), a graft-modified ethylene·α-olefin copolymer was prepared as follows.

[0231] Into a 500 mL glass reactor equipped with a stirrer, a nitrogen blowing tube, a water-cooled condenser, and a thermometer, 120 g of the ethylene·α-olefin copolymer (X-1), 15 g of 2-methyl-3-butene-2-ol, and 3 g of di-tert-butyl peroxide were added, and nitrogen substitution was carried out for 1 hour to expel dissolved oxygen. Then, the temperature inside the reactor was raised to 160 °C, and after reacting for 3 hours, the temperature inside the reactor was raised to 180 °C, and unreacted 2-methyl-3-butene-2-ol and decomposition products of di-tert-butyl peroxide were removed under reduced pressure (10 Torr) to obtain a graft-modified ethylene·α-olefin copolymer.

[0232] Here, the graft-modified ethylene·α-olefin copolymer obtained in this production example is designated as the graft-modified ethylene·α-olefin copolymer (B-1). The graft ratio of the obtained graft-modified ethylene / α-olefin copolymer (B-1) was 9% by mass. The above graft ratio was determined by quantifying the hydroxyl group content in the sample by measuring the hydroxyl value by the acetylation method and calculating the content of the hydroxyl group-containing graft monomer component from that value. Also, the weight average molecular weight (Mw): 5300, the molecular weight distribution (Mw / Mn): 1.8, and the kinematic viscosity at 100 °C: 200 mm 2 / s, and no melting point was observed.

[0233] [Production Example B2] Synthesis of Graft-Modified Ethylene / α-Olefin Copolymer (B-2) Using the ethylene / α-olefin copolymer (X-2) as the raw material ethylene / α-olefin copolymer (ethylene / α-olefin copolymer (B0)), a graft-modified ethylene / α-olefin copolymer was prepared as follows.

[0234] Into a 500 mL glass reactor equipped with a stirrer equipped with a nitrogen blowing tube, a water-cooled condenser, and a thermometer, 120 g of an ethylene / α-olefin copolymer (X-2), 15 g of 2-methyl-3-buten-2-ol, and 3 g of di-tert-butyl peroxide were added, and nitrogen substitution was carried out for 1 hour to expel dissolved oxygen. Then, the temperature inside the reactor was raised to 160 °C, and after reacting for 3 hours, the temperature inside the reactor was raised to 180 °C, and unreacted 2-methyl-3-buten-2-ol and decomposition products of di-tert-butyl peroxide were removed under reduced pressure (10 Torr) to obtain a graft-modified ethylene / α-olefin copolymer.

[0235] Here, the graft-modified ethylene / α-olefin copolymer obtained in this production example is designated as the graft-modified ethylene / α-olefin copolymer (B-2). The graft ratio of the obtained graft-modified ethylene / α-olefin copolymer (B-2) was 8% by mass. The above graft ratio was determined by quantifying the hydroxyl group content in the sample by measuring the hydroxyl value by the acetylation method and calculating the content of the hydroxyl group-containing graft monomer component from that value. Also, weight-average molecular weight (Mw): 5000, molecular weight distribution (Mw / Mn): 1.8, kinematic viscosity at 100 °C: 190 mm 2 / s, and no melting point was observed.

[0236] [Production Example B3] Synthesis of graft-modified ethylene·α-olefin copolymer (B-3) The reaction was carried out in the same manner as in Production Example B1 except that the ethylene·α-olefin copolymer (X-3) was used as a raw material to obtain a graft-modified ethylene·α-olefin copolymer (B-3).

[0237] The graft ratio of the obtained graft-modified ethylene·α-olefin copolymer (B-3) was 8% by mass. The above graft ratio was determined by quantifying the hydroxyl group content in the sample by measuring the hydroxyl value by the acetylation method and calculating the content of the hydroxyl group-containing graft monomer component from that value. Also, weight-average molecular weight (Mw): 18000, molecular weight distribution (Mw / Mn): 2.9, kinematic viscosity at 100 °C: 2700 mm 2 / s, and no melting point was observed.

[0238] The data of the obtained graft-modified ethylene·α-olefin copolymers (B-1) to (B-3) are shown below.

[0239]

Table 2

[0240] [Crosslinking agent (C)] As the crosslinking agent (C-1), Takenate D-101E (isocyanate-based compound, "Takenate" is a registered trademark of Mitsui Chemicals, Inc.) manufactured by Mitsui Chemicals, Inc. was used.

[0241] [Examples 1 to 4 and Comparative Examples 1 to 5] In each of Examples 1 to 4 and Comparative Examples 1 to 5, an ethyl acetate / toluene solution containing the above (meth)acrylic resin (A-1), and Either graft-modified ethylene·α-olefin copolymers (B-1) to (B-3) or ethylene·α-olefin copolymers (X-1) to (X-3), and a crosslinking agent (C), and were stirred and mixed at room temperature to obtain a pressure-sensitive adhesive composition in the form of an ethyl acetate / toluene solution. Here, in the pressure-sensitive adhesive composition, the mass ratio of the (meth)acrylic resin (A-1) contained in the ethyl acetate / toluene solution, either of the graft-modified ethylene·α-olefin copolymers (B-1) to (B-3) or ethylene·α-olefin copolymers (X-1) to (X-3), and the mass of the crosslinking agent (C) was as described in Table 3. In addition, in the evaluation of each physical property described later, an ethyl acetate / toluene solution (hereinafter, "ethyl acetate / toluene (40 / 60 mass%) solution of the pressure-sensitive adhesive composition") obtained by adding toluene to the mixture obtained by the above stirring and mixing and adjusting the mass ratio of ethyl acetate to toluene to 40 / 60 was used.

[0242] [Gel fraction] The evaluation of the gel fraction was carried out as follows for each of the ethyl acetate / toluene (40 / 60 mass%) solutions of the pressure-sensitive adhesive compositions obtained in the examples and comparative examples. The ethyl acetate / toluene (40 / 60 mass%) solution of the pressure-sensitive adhesive composition was applied to a release paper so that the film thickness after drying would be 25 μm, and dried at 100°C for 10 minutes to obtain an adhesive layer. Then, it was left at 50°C for 3 days to sufficiently crosslink the pressure-sensitive adhesive composition (by this, the adhesive layer was an adhesive layer composed of a crosslinked body of the pressure-sensitive adhesive composition). The release paper was removed, 100 mg was cut out from the adhesive layer as a sample, the sample was wrapped with a 300-mesh wire mesh, immersed in toluene adjusted to 23°C for 24 hours, and then vacuum dried at 80°C for 1 hour. The mass percentage of the insoluble sample remaining in the wire mesh with respect to the mass of the sample before toluene immersion was calculated as the gel fraction.

[0243] [Haze] The haze evaluation was carried out as follows for each of the ethyl acetate / toluene (40 / 60% by mass) solutions of the pressure-sensitive adhesive compositions obtained in the examples and comparative examples. The ethyl acetate / toluene (40 / 60% by mass) solution of the pressure-sensitive adhesive composition was applied to a release paper so that the film thickness after drying would be 25 μm, dried at 100 °C for 10 minutes, and then a 25-μm PET film was pressure-bonded to the coated surface to prepare a pressure-sensitive adhesive sheet having a base material layer made of a PET film and a pressure-sensitive adhesive layer made of the pressure-sensitive adhesive composition. It was left standing at 50 °C for 3 days to sufficiently crosslink the pressure-sensitive adhesive composition.

[0244] The release paper of the above pressure-sensitive adhesive sheet was peeled off to expose the pressure-sensitive adhesive layer, and a 25-μm PET film was pressure-bonded to the exposed pressure-sensitive adhesive layer to obtain a test piece. The structure of the test piece was PET film / pressure-sensitive adhesive layer / PET film = 25 / 25 / 25 μm. Thereafter, in accordance with JIS K7136, the haze of the above test piece was measured.

[0245] [Total light transmittance] The total light transmittance evaluation was carried out as follows for each of the ethyl acetate / toluene (40 / 60% by mass) solutions of the pressure-sensitive adhesive compositions obtained in the examples and comparative examples. The ethyl acetate / toluene (40 / 60% by mass) solution of the pressure-sensitive adhesive composition was applied to a release paper so that the film thickness after drying would be 25 μm, dried at 100 °C for 10 minutes, and then a 25-μm PET film was pressure-bonded to the coated surface to prepare a pressure-sensitive adhesive sheet having a base material layer made of a PET film and a pressure-sensitive adhesive layer made of the pressure-sensitive adhesive composition. It was left standing at 50 °C for 3 days to sufficiently crosslink the pressure-sensitive adhesive composition.

[0246] The release paper of the above pressure-sensitive adhesive sheet was peeled off to expose the pressure-sensitive adhesive layer, and a 25-μm PET film was pressure-bonded to the exposed pressure-sensitive adhesive layer to obtain a test piece. The structure of the test piece was PET film / pressure-sensitive adhesive layer / PET film = 25 / 25 / 25 μm. In accordance with JIS K7361, the total light transmittance of the above test piece was measured.

[0247] [Adhesiveness evaluation] The adhesiveness evaluation was carried out as follows for each of the ethyl acetate / toluene (40 / 60 mass%) solutions of the adhesive compositions obtained in the examples and comparative examples. The ethyl acetate / toluene (40 / 60 mass%) solution of the adhesive composition was applied to the release paper so that the film thickness after drying would be 25 μm, dried at 100°C for 10 minutes, and then a 50-μm PET film was pressure-bonded to the coated surface to produce an adhesive sheet having a base material layer made of a PET film and an adhesive layer made of the adhesive composition. It was left at 50°C for 3 days to sufficiently crosslink the adhesive composition.

[0248] The above adhesive sheet was cut into pieces 25 mm wide and 150 mm long to obtain test pieces. The release paper of the above test pieces was peeled off to expose the adhesive layer, and in an atmosphere of 23°C, the exposed adhesive layer was brought into contact with a PP plate, and a rubber roll with a mass of 2 kg was reciprocated twice to pressure-bond the test pieces. After leaving it for 20 minutes, in accordance with JIS Z0237, the 180° peel strength was measured at a speed of 300 mm / min.

[0249] The adhesiveness was evaluated based on the obtained peel strength. The evaluation results are shown in Table 3. The meanings of the symbols in the table are as follows. 〇: Peel strength is 3 N / 25 mm or more △: Peel strength is less than 3 N / 25 mm and 1 N / 25 mm or more ×: Peel strength is less than 1 N / 25 mm Here, the symbol "〇" indicates that the adhesive sheet and the PP plate are in a state of being adhered with sufficient strength. The symbol "△" indicates that the adhesive sheet and the PP plate are in a state of being adhered with a certain degree of strength. The symbol "×" indicates that there is a poor adhesion state (non-adhesion state) between the adhesive sheet and the PP plate.

[0250] The adhesive sheet having the adhesive layer of the present invention is preferable because the higher the adhesive strength, the more it can prevent the peeling of the base materials.

[0251] [Low-temperature flexibility evaluation] The low-temperature flexibility evaluation was performed as follows for each of the ethyl acetate / toluene (40 / 60% by mass) solutions of the pressure-sensitive adhesive compositions obtained in the examples and comparative examples. An ethyl acetate / toluene (40 / 60% by mass) solution of the pressure-sensitive adhesive composition was applied to a release paper so that the film thickness after drying would be 25 μm, dried at 100°C for 10 minutes, and the release paper was peeled off from the resulting laminate to obtain a sheet made of the pressure-sensitive adhesive composition.

[0252] For the obtained sheet of the pressure-sensitive adhesive composition, using a rheometer (ARES-G2 manufactured by TA Instruments), the dynamic viscoelasticity at -20°C was measured at a frequency of 1 Hz with a measuring jig of parallel plates (8 mm in diameter). Specifically, a sample formed by shaping the sheet of the pressure-sensitive adhesive composition into a disk shape with a diameter of 8 mm and a thickness of 0.4 mm was used, and the sample was sandwiched between two parallel plates (8 mm in diameter) attached to the rheometer (the gap between the parallel plates was set to 0.4 mm.), and the loss elastic modulus G" and the storage elastic modulus G' at -20°C were measured at a frequency of 1 Hz. The low-temperature flexibility was evaluated based on the obtained storage elastic modulus G'. The evaluation results are shown in Table 3. The meanings of the symbols in the table are as follows. 〇: The storage elastic modulus G' is 0.1 MPa or more and less than 0.5 MPa △: The storage elastic modulus G' is 0.5 MPa or more and less than 1.0 MPa ×: The storage elastic modulus G' is 1.0 MPa or more

[0253] Here, the symbol "〇" indicates that the adhesive is sufficiently soft, and when the pressure-sensitive adhesive sheet obtained in combination with the base material is bent, the adhesive can sufficiently follow the movement of the base material, and peeling of the adhesive from the base material is extremely unlikely to occur (that is, it is extremely unlikely to cause peeling of the adhesive due to insufficient follow-up when the base material is bent).

[0254] The symbol "△" indicates that the adhesive is somewhat soft and when the adhesive sheet obtained by combining with the substrate is bent, the adhesive can follow the movement of the substrate to a certain extent, and the peeling of the adhesive from the substrate is somewhat difficult to occur (that is, it is somewhat difficult to cause peeling of the adhesive due to insufficient follow - up when the substrate is bent).

[0255] The symbol "×" indicates that the adhesive is hard and when the adhesive sheet obtained by combining with the substrate is bent, the adhesive cannot follow the movement of the substrate, and the peeling of the adhesive from the substrate is likely to occur (that is, it is likely to cause peeling of the adhesive due to insufficient follow - up when the substrate is bent).

[0256] The adhesive sheet having the adhesive layer of the present invention shows better low - temperature flexibility as the storage elastic modulus G' at - 20°C is lower. From this, when the adhesive layer of the present invention is combined with a substrate to form an adhesive sheet, even when the substrate is bent, the adhesive can follow, and peeling of the adhesive can be suppressed, which is preferable.

[0257] [Moisture Resistance Evaluation] The moisture resistance evaluation was carried out as follows for each of the ethyl acetate / toluene (40 / 60 mass%) solutions of the pressure - sensitive adhesive compositions obtained in the examples and comparative examples. The ethyl acetate / toluene (40 / 60 mass%) solution of the pressure - sensitive adhesive composition was applied to a 50 - μm - thick cellulose triacetate film (TAC film) so that the film thickness after drying would be 50 μm. After drying at 100°C for 10 minutes, a 50 - μm - thick TAC film was pressure - bonded to the coated surface to prepare an adhesive sheet. It was left at 50°C for 3 days to sufficiently cross - link the pressure - sensitive adhesive composition.

[0258] The above - mentioned adhesive sheet was cut into pieces 50 mm long and 50 mm wide to obtain test pieces. For the obtained test pieces, in accordance with the MOCON method, the moisture permeability (g / m 2 ·24h) was measured under the conditions of 40°C, 90% RH, and 24 hours.

[0259] The moisture resistance was evaluated based on the obtained moisture permeability. Here, it is considered that a pressure-sensitive adhesive sheet with a low moisture permeability exhibits high moisture resistance. The evaluation results are shown in Table 3. The meanings of the symbols in the table are as follows. 〇: The moisture permeability of the pressure-sensitive adhesive sheet to be evaluated is less than 0.50 times the moisture permeability of the pressure-sensitive adhesive sheet obtained in Comparative Example 4 (that is, the reduction rate with respect to the moisture permeability of the pressure-sensitive adhesive sheet obtained in Comparative Example 4 is 50% or more and less than 100%). △: The moisture permeability of the pressure-sensitive adhesive sheet to be evaluated is more than 0.50 times and less than or equal to 0.90 times the moisture permeability of the pressure-sensitive adhesive sheet obtained in Comparative Example 4 (that is, the reduction rate with respect to the moisture permeability of the pressure-sensitive adhesive sheet obtained in Comparative Example 4 is 10% or more and less than 50%). ×: The moisture permeability of the pressure-sensitive adhesive sheet to be evaluated exceeds 0.90 times the moisture permeability of the pressure-sensitive adhesive sheet obtained in Comparative Example 4 (that is, the moisture permeability has not decreased at all compared to the pressure-sensitive adhesive sheet obtained in Comparative Example 4, or the reduction rate with respect to the moisture permeability of the pressure-sensitive adhesive sheet obtained in Comparative Example 4 is less than 10%).

[0260] The symbol "〇" or "△" indicates that the moisture permeability of the pressure-sensitive adhesive sheet to be evaluated is less than that of the pressure-sensitive adhesive sheet obtained in Comparative Example 4 to a certain extent or more, and the pressure-sensitive adhesive composition constituting the pressure-sensitive adhesive sheet has a certain degree or more excellent moisture resistance compared to the pressure-sensitive adhesive composition (Comparative Example 4) that does not contain the graft-modified ethylene·α-olefin copolymer (B-1) to (B-3) or the ethylene·α-olefin copolymer (X-1) to (X-3). Here, the pressure-sensitive adhesive composition scored with "〇" has high moisture resistance and is less likely to cause whitening, foaming, or blistering of the adhesive under high-durability conditions when used as an adhesive for a pressure-sensitive adhesive sheet or the like. In addition, the pressure-sensitive adhesive composition scored with "△" has a certain degree of moisture resistance and is less likely to cause whitening, foaming, or blistering of the adhesive under high-durability conditions when used as an adhesive for a pressure-sensitive adhesive sheet or the like.

[0261] On the one hand, the symbol "×" indicates that the moisture permeability of the pressure-sensitive adhesive sheet to be evaluated is equivalent to that of the pressure-sensitive adhesive sheet obtained in Comparative Example 4, and the pressure-sensitive adhesive composition constituting the pressure-sensitive adhesive sheet does not contain the graft-modified ethylene-α-olefin copolymers (B-1) to (B-3) or the ethylene-α-olefin copolymers (X-1) to (X-3), meaning that it does not exhibit sufficient moisture resistance similar to the pressure-sensitive adhesive composition (Comparative Example 4). That is, the pressure-sensitive adhesive composition scored with "×" has insufficient moisture resistance and tends to cause whitening, foaming, and blistering of the pressure-sensitive adhesive under high-durability conditions when used as a pressure-sensitive adhesive for pressure-sensitive adhesive sheets and the like.

[0262] Since the pressure-sensitive adhesive sheet having the pressure-sensitive adhesive layer of the present invention exhibits more excellent moisture resistance as the reduction rate of the moisture permeability is lower, it can suppress the whitening, foaming, and blistering of the pressure-sensitive adhesive even under high-durability conditions, which is preferable.

[0263]

Table 3

Claims

1. An adhesive composition comprising a (meth)acrylic resin (A), a graft-modified ethylene / α-olefin copolymer (B) satisfying the following (b-1) to (b-2), and a crosslinking agent (C), and an adhesive layer having a gel fraction of 40% by mass or more; (b-1) including a main chain portion derived from an ethylene / α-olefin copolymer (B0); (b-2) including a graft portion derived from an ethylenically unsaturated monomer having a hydroxyl group.

2. The graft-modified ethylene / α-olefin copolymer (B) further satisfies the following (b-3) to (b-6), when the total content of the (meth)acrylic resin (A), the graft-modified ethylene / α-olefin copolymer (B), and the crosslinking agent (C) is 100% by mass, the amount of the (meth)acrylic resin (A) is 47% by mass or more and 99% by mass, the amount of the graft-modified ethylene / α-olefin copolymer (B) is 0.5% by mass or more and 50% by mass or less, and the amount of the crosslinking agent (C) is 0.5% by mass or more and 5% by mass or less. The adhesive layer according to Claim 1; (b-3) the proportion of the graft portion is 0.1% by mass or more and less than 70% by mass (however, the total amount of the main chain portion and the graft portion is 100% by mass); (b-4) the weight average molecular weight (Mw) determined by gel permeation chromatography (GPC) is 1,500 to 30,000; (b - 5) having a kinematic viscosity at 100 °C of 10 to 5,000 mm 2 / s; (b-6) no melting point is observed by differential scanning calorimetry (DSC).

3. The adhesive layer according to Claim 1, having a haze of 5.0% or less measured in accordance with JIS K7136.

4. The adhesive layer according to Claim 1, having a total light transmittance of 80% or more measured in accordance with JIS K7361.

5. The adhesive layer according to Claim 1, having a thickness of 5 to 200 μm.

6. An adhesive sheet having the adhesive layer according to any one of Claims 1 to 5.

7. A laminate having the adhesive sheet according to Claim 6.

8. An optical member having the adhesive sheet according to Claim 6.

9. A touch panel type input / output device or an image display device having the adhesive sheet according to Claim 6.

10. A method for producing an adhesive sheet including an adhesive layer, comprising a (meth)acrylic resin (A), A graft-modified ethylene / α-olefin copolymer (B) produced by the following method (α) or method (β) and satisfying the following requirements (b-1) to (b-2), and a crosslinking agent (C), are mixed to obtain a composition containing the (meth)acrylic resin (A), the graft-modified ethylene / α-olefin copolymer (B), and the crosslinking agent (C) (step (S1)); forming an adhesive layer from the composition obtained in the step (S1) (step (S2)); A method for producing an adhesive sheet comprising: (b-1) including a main chain portion derived from an ethylene / α-olefin copolymer; (b-2) including a graft portion derived from an ethylenically unsaturated monomer having a hydroxyl group; Method (α): In the presence of a catalyst system containing a crosslinking metallocene compound (P) represented by the following (Formula 1) and at least one compound (Q) selected from the group consisting of an organometallic compound (Q-1), an organoaluminum oxy compound (Q-2), and a compound (Q-3) that reacts with the crosslinking metallocene compound (P) to form an ion pair, ethylene and an α-olefin are solution-polymerized to obtain an ethylene / α-olefin copolymer (B0) (step (SB1)); adding the ethylenically unsaturated monomer having a hydroxyl group to the ethylene / α-olefin copolymer (B0) and subjecting it to graft copolymerization (step (SB2)); A method comprising: 【Chemical Formula 1】 [(In formula (1), R 1 , R 2 , R 3 , R 4 , R 5 , R 8 , R 9 and R 12 are each independently a hydrogen atom, a hydrocarbon group or a silicon-containing hydrocarbon group, and a plurality of adjacent groups may be linked to each other to form a ring structure, R 6 and R 11 are the same group as each other and are a hydrogen atom, a hydrocarbon group or a silicon-containing hydrocarbon group, R 7 and R 10 are the same group as each other and are a hydrogen atom, a hydrocarbon group or a silicon-containing hydrocarbon group, R 6 and R 7 may be bonded to a hydrocarbon having 2 to 3 carbon atoms to form a ring structure, R 10 and R 11 may be combined with a hydrocarbon having 2 to 3 carbon atoms to form a ring structure, R 6 , R 7 , R 10 and R 11 are not simultaneously hydrogen atoms, R 13 and R 14 are each independently a hydrogen atom, a hydrocarbon group or a silicon-containing hydrocarbon group, and may be linked to each other to form a ring structure, Y is a carbon atom or a silicon atom, M is Ti, Zr or Hf, Q is independently a halogen atom, a hydrocarbon group, an anionic ligand or a neutral ligand capable of coordinating to a lone pair of electrons, j is an integer from 1 to 4. Method (β): In the presence of a vanadium-based catalyst composed of a soluble vanadium compound (V) and an organoaluminum compound (Q'), ethylene and an α-olefin are solution-polymerized to obtain an ethylene / α-olefin copolymer (B0) (step (SB1')); adding the ethylenically unsaturated monomer having a hydroxyl group to the ethylene / α-olefin copolymer (B0) and subjecting it to graft copolymerization (step (SB2)); A method comprising:

11. The substituent R of the crosslinked metallocene compound (P) represented by the above (Formula 1) 13 and R 14 The production method according to claim 10, wherein either one or both of them are aryl groups.

12. Substituent R of the crosslinked metallocene compound (P) represented by the above (Formula 1) 13 and R 14 are both aryl groups, and either one of the substituents R 2 and R 3 is a saturated hydrocarbon group having 4 carbon atoms. The production method according to claim 10

Images