Composition for adhesive, hot melt adhesive composition, and adhesive

Abstract

The present invention provides a composition for an adhesive agent, which contains a block copolymer composition and an alkyl radical scavenger, the block copolymer composition comprising a block copolymer A1 represented by a specific general formula (1) or a block copolymer A2 represented by a specific general formula (2), the weight-average molecular weight (Mw) of the entire block copolymer composition being 300,000-800,000, the weight-average molecular weight (Mw) of the block copolymer composition being 2,000-3,000, and the weight-average molecular weight (Mw) of the block copolymer composition being 2,000-3,000. The content of the alkyl radical scavenger is 0.05-2 parts by mass per 100 parts by mass of the block copolymer composition.

Description

Technical Field

[0001] The present invention relates to an adhesive composition, and a hot-melt adhesive composition and an adhesive formed using the adhesive composition. Background Art

[0002] Hot melt adhesives have the property of solidifying in a short time after cooling from a heated molten state, and can efficiently bond various products. Moreover, since they do not require solvents, they are highly safe for the human body, so they are used in various fields. For example, in the manufacture of paper, cartons, and film packaging adhesives for food, clothing, electronic equipment, cosmetics, etc., and sanitary products such as diapers and sanitary products, hot melt adhesives are widely used as adhesives for bonding the components that constitute them, and as adhesives that constitute the adhesive layer of tapes and labels.

[0003] As a base polymer for constituting a hot melt adhesive, various thermoplastic resins are used, and for example, aromatic-conjugated diene copolymers such as styrene-isoprene block copolymers and styrene-butadiene block copolymers are known.

[0004] For example, Patent Document 1 describes a composition comprising a block copolymer containing an aromatic vinyl monomer unit, an antioxidant (I), an antioxidant (II), and an antioxidant (III) as an optional component, wherein the antioxidant (I) is a compound containing a hindered phenol structure in which two ortho positions of a hydroxyl group bonded to a benzene ring are substituted with tert-butyl groups, the antioxidant (II) is a compound containing a sulfur atom in the molecule (excluding the antioxidant (I)), the antioxidant (III) is a polymer alkyl radical scavenger, and the content of the antioxidant (I) is about 100%. The content of the antioxidant (II) is in the range of 0.10 to 1.00 parts by mass relative to 100 parts by mass of the block copolymer, the total content of the antioxidant (I), the antioxidant (II) and the antioxidant (III) is in the range of 0.15 to 1.50 parts by mass relative to 100 parts by mass of the block copolymer, and the content of the conjugated diene dimer in the composition is 10 ppm by weight or less relative to the composition.

[0005] Prior art literature

[0006] Patent Literature

[0007] Patent document 1: Japanese Patent Application Publication No. 2020-117663. Summary of the invention

[0008] Problem that the invention aims to solve

[0009] In recent years, there has been a demand for further improvement in adhesive properties, and a technology capable of improving adhesive properties even higher than that of Patent Document 1 has been desired.

[0010] The present invention has been made in view of such actual circumstances, and an object of the present invention is to provide an adhesive composition that has excellent processability and can form an adhesive having excellent adhesive properties.

[0011] Solutions for solving problems

[0012] The present inventors have conducted intensive studies to solve the above-mentioned problems and have found that the above-mentioned problems can be solved by using a block copolymer composition containing a specific block copolymer A1 or a specific block copolymer A2 and having an overall weight average molecular weight (Mw) of 300,000 to 800,000 as a block copolymer composition and adding a specific amount of an alkyl radical scavenger thereto to form an adhesive composition, thereby completing the present invention.

[0013] That is, according to the present invention, the following adhesive composition can be provided.

[0014] [1] An adhesive composition comprising a block copolymer composition and an alkyl radical scavenger, wherein the block copolymer composition comprises a block copolymer A1 represented by the following general formula (1) or a block copolymer A2 represented by the following general formula (2),

[0015] The weight average molecular weight (Mw) of the block copolymer composition as a whole is 300,000 to 800,000.

[0016] The content of the alkyl radical scavenger is 0.05 to 2 parts by mass relative to 100 parts by mass of the block copolymer composition.

[0017]

[0018] (In the general formula (1), Ar 1 is an aromatic monovinyl polymer block, D 1 and D 2 are conjugated diene polymer blocks, m is an integer greater than 1, n is an integer greater than 1, m+n is an integer greater than 3, and X 1 is the residue of a multifunctional coupling agent)

[0019]

[0020] (In the general formula (2), Ar is an aromatic monovinyl polymer block, D is a conjugated diene polymer block, p is an integer greater than 3, and X is a residue of a multifunctional coupling agent).

[0021] [2] The adhesive composition according to [1], wherein the molecular weight distribution (Mw / Mn) of the block copolymer A1 or the block copolymer A2 is 1.40 or less,

[0022] The total content of the block copolymer A1 and the block copolymer A2 in the block copolymer composition is 10% by mass or more.

[0023] [3] The adhesive composition according to [1] or [2], wherein the block copolymer composition further comprises a diblock copolymer B represented by the following general formula (3) or a polymer C represented by the following general formula (4),

[0024] The molecular weight distribution (Mw / Mn) of the diblock copolymer B or the polymer C is 1.20 or less,

[0025] The total content of the diblock copolymer B and the polymer C in the block copolymer composition is 60% by mass or less,

[0026] The content of the aromatic monovinyl monomer unit in the block copolymer composition is 5 to 40% by mass.

[0027] The block copolymer composition has a type A hardness of 25 to 65 as measured using a durometer hardness tester (type A) in accordance with JIS K6253.

[0028]

[0029]

[0030] (In general formula (3) and general formula (4), Ar 3 is an aromatic monovinyl polymer block, D 3 and D 4 conjugated diene polymer blocks, respectively).

[0031] [4] The adhesive composition according to any one of [1] to [3], wherein the melt index measured in accordance with ASTM D1238 (condition G, 200°C, 5 kg load) is 1.5 to 50 g / 10 min.

[0032] [5] The adhesive composition according to any one of [1] to [4], wherein the block copolymer composition comprises the block copolymer A1,

[0033] In the above block copolymer A1, Ar 1 -D 1 The mass of the branched chain is expressed relative to that of D 2 The ratio of the mass of the branched chain (Ar 1-D 1 ) / D 2 ) is 1.0 / 0.15~1.0 / 1.75.

[0034] [6] The adhesive composition according to any one of [1] to [5], wherein the block copolymer composition contains the block copolymer A1,

[0035] In the above block copolymer A1, Ar 1 -D 1 The conjugated diene polymer block D in the branched chain 1 The weight average molecular weight (Mw(D 1 )) Relative to D 2 The weight average molecular weight (Mw(D 2 )) ratio ((Mw(D 1 )) / (Mw(D 2 ))) is 1.0 / 0.3~1.0 / 1.1.

[0036] [7] The adhesive composition according to any one of [1] to [6], wherein the polyfunctional coupling agent is a compound having two or more radical polymerizable groups in a molecule.

[0037] [8] The adhesive composition according to any one of [1] to [7], wherein the polyfunctional coupling agent is divinylbenzene.

[0038] [9] The adhesive composition according to any one of [1] to [8], wherein the conjugated diene polymer block is an isoprene polymer block.

[0039]

[10] The adhesive composition according to any one of [1] to [9], wherein the alkyl radical scavenger is at least one selected from 2-[1-(2-hydroxy-3,5-di-tert-pentylphenyl)ethyl]-4,6-di-tert-pentylphenyl acrylate and 2-tert-butyl-6-(3-tert-butyl-2-hydroxy-5-methylbenzyl)-4-methylphenyl acrylate.

[0040]

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

[10] , further comprising at least one antioxidant selected from hindered phenol-based antioxidants, phosphorus-based antioxidants, sulfur-based antioxidants and benzofuranone-based antioxidants,

[0041] The content of the antioxidant is 0.01 to 10 parts by mass based on 100 parts by mass of the block copolymer composition.

[0042] Furthermore, according to the present invention, the following hot-melt adhesive composition and adhesive formed using the above-mentioned adhesive composition can be provided.

[0043]

[12] A hot-melt adhesive composition comprising the adhesive composition according to any one of [1] to

[11] , a tackifier resin, and a crosslinking agent.

[0044] The content of the tackifier resin is 10 to 400 parts by mass, and the content of the crosslinking agent is 0.01 to 50 parts by mass, based on 100 parts by mass of the block copolymer composition in the adhesive composition.

[0045]

[13] The hot-melt adhesive composition according to

[12] , wherein the hot-melt adhesive composition contains 0 to 200 parts by mass of a plasticizer based on 100 parts by mass of the block copolymer composition in the adhesive composition.

[0046]

[14] An adhesive comprising the hot-melt adhesive composition according to

[12] or

[13] , which is obtained by crosslinking the block copolymer A1 or the block copolymer A2 in the hot-melt adhesive composition.

[0047] Effects of the Invention

[0048] According to the present invention, it is possible to provide an adhesive composition which has excellent processability and can form an adhesive having excellent adhesive properties. DETAILED DESCRIPTION

[0049] <Adhesive composition>

[0050] The adhesive composition of the present invention contains the block copolymer composition described below and an alkyl radical scavenger.

[0051] The adhesive composition of the present invention has excellent processability, can well implement processing requiring strong shear stress (e.g., biaxial extrusion processing), and can form an adhesive having excellent hot melt processability. Furthermore, the adhesive composition of the present invention has not only excellent processability but also excellent cross-linking properties, and can form an adhesive having excellent adhesive properties (heat resistance stability, high temperature adhesiveness, and initial adhesiveness).

[0052] 1. Block copolymer composition

[0053] The block copolymer composition used in the present invention comprises a block copolymer A1 represented by the general formula (1) or a block copolymer A2 represented by the general formula (2), and the weight average molecular weight (Mw) of the block copolymer composition as a whole is 300000 to 800000. The block copolymer composition used in the present invention may contain either the block copolymer A1 or the block copolymer A2, or both.

[0054] The block copolymer composition used in the present invention is a composition of a polymer component containing a conjugated diene polymer block in the adhesive composition of the present invention, and contains a block copolymer A1 represented by the general formula (1) or a block copolymer A2 represented by the general formula (2).

[0055] (1-1) Block copolymer A1

[0056] The block copolymer A1 is a block copolymer represented by the following general formula (1):

[0057]

[0058] (In the general formula (1), Ar 1 is an aromatic monovinyl polymer block, D 1 and D 2 are conjugated diene polymer blocks, m is an integer greater than 1, n is an integer greater than 1, m+n is an integer greater than 3, and X 1 It is the residue of a multifunctional coupling agent. )

[0059] In the general formula (1), Ar 1 -D 1 and D 2 and X 1 The bonded side chain, m is 1 Bonded by Ar 1 -D 1 The number of branches represented by n is the same as X 1 Bonded by D 2 The number of branches represented by m+n is composed of Ar 1 -D 1 The branched chain represented by D 2 The total number of branches represented by is therefore the number of branches in the block copolymer A1. 1 is an aromatic monovinyl polymer block, D 1 and D 2 It is a conjugated diene polymer block.

[0060] In the general formula (1), m is an integer of 1 or more, n is an integer of 1 or more, and m+n is an integer of 3 or more. That is, the block copolymer A1 has a branched structure consisting of three or more branches and contains Ar1 -D 1 The branched chain represented by D 2 Both of the branched chains (conjugated diene polymer block chains) represented are considered as branched chains.

[0061] In the general formula (1), m+n is an integer greater than 3, and is not particularly limited, but is preferably an integer from 4 to 20, more preferably an integer from 5 to 15, and even more preferably an integer from 6 to 10. By making m+n within the above range, the processability and crosslinking properties of the adhesive composition and the adhesive properties of the obtained adhesive can be further improved. m+n can be adjusted by adjusting the Ar 1 -D 1 The branched chain represented by D 2 The structure of the branched chains represented and the coupling conditions (such as the type and amount of the multifunctional coupling agent used) are adjusted.

[0062] The block copolymer A1 may be composed of only one type of block copolymer having substantially a single structure, or may be composed of two or more types of block copolymers having substantially different structures.

[0063] In addition, the block copolymer A1 may be a mixture of block copolymers having different values ​​of m, n, and m+n. When the average molecular weight of the block copolymer A1 is obtained by using the measurement of high performance liquid chromatography described later to calculate m, n, and m+n, the average values ​​of m, n, and m+n of the plurality of block copolymers in the mixture are calculated, and therefore, these calculated values ​​may not necessarily be integers. In the present invention, the integers closest to the calculated values ​​may be designated as m, n, and m+n.

[0064] (1-1-1) Aromatic monovinyl polymer block Ar 1

[0065] The aromatic monovinyl polymer block Ar constituting the block copolymer A1 1 The aromatic monovinyl polymer block Ar is a polymer block having an aromatic monovinyl monomer unit as a structural unit. 1The aromatic monovinyl monomer of the aromatic monovinyl monomer unit is not particularly limited as long as it is an aromatic vinyl compound having a free radical polymerizable group, and examples thereof include styrene, α-methylstyrene, 2-methylstyrene, 3-methylstyrene, 4-methylstyrene, 2-ethylstyrene, 3-ethylstyrene, 4-ethylstyrene, 2,4-diisopropylstyrene, 2,4-dimethylstyrene, 4-tert-butylstyrene, 5-tert-butyl-2-methylstyrene, 2-chlorostyrene, 3-chlorostyrene, 4-chlorostyrene, 4-bromostyrene, 2-methyl-4,6-dichlorostyrene, 2,4-dibromostyrene, vinylnaphthalene, etc. Among these, styrene is preferred as the aromatic monovinyl monomer. These aromatic monovinyl monomers are preferably used in the aromatic monovinyl polymer block Ar. 1 They can be used alone or in combination of two or more.

[0066] Aromatic monovinyl polymer block Ar 1 It may contain monomer units other than aromatic monovinyl monomer units. As monomers constituting monomer units other than aromatic monovinyl monomer units, there may be mentioned conjugated diene monomers such as 1,3-butadiene, isoprene (2-methyl-1,3-butadiene), α,β-unsaturated nitrile monomers, unsaturated carboxylic acid or anhydride monomers, unsaturated carboxylic acid ester monomers, and non-conjugated diene monomers. Aromatic monovinyl polymer block Ar 1 The content of monomer units other than the aromatic monovinyl monomer units in the monomer unit is preferably 20% by mass or less, more preferably 10% by mass or less, and particularly preferably substantially 0% by mass.

[0067] Aromatic monovinyl polymer block Ar 1 The weight average molecular weight (Mw(Ar 1 )) is not particularly limited and can be in the range of 7000 to 18000, preferably in the range of 7500 to 17000, and more preferably in the range of 8000 to 16000.

[0068] In addition, in the present invention, the weight average molecular weight (Mw) and number average molecular weight (Mn) of polymer blocks, branches, block copolymers, block copolymer compositions, etc. are obtained as polystyrene conversion values ​​measured by high performance liquid chromatography. More specifically, the weight average molecular weight and number average molecular weight are measured by the method described in the Examples.

[0069] (1-1-2) Conjugated diene polymer block D 1

[0070] Conjugated diene polymer block D constituting block copolymer A1 1It is a polymer block with a conjugated diene monomer unit as a structural unit. 1 The conjugated diene monomer of the conjugated diene monomer unit is not particularly limited as long as it is a conjugated diene compound, and examples thereof include 1,3-butadiene, isoprene (2-methyl-1,3-butadiene), 2,3-dimethyl-1,3-butadiene, 2-chloro-1,3-butadiene, 1,3-pentadiene, 1,3-hexadiene, etc. Among these conjugated diene monomers, 1,3-butadiene and / or isoprene are preferably used, and isoprene is particularly preferably used. Conjugated diene polymer block D 1 The isoprene polymer block is particularly preferred. By using isoprene monomer units to constitute the conjugated diene polymer block D 1 , which can further improve the processability and crosslinking properties of the adhesive composition and the adhesive properties of the obtained adhesive. 1 In the embodiment of the present invention, two or more of the above-mentioned compounds can be used alone or in combination. 1 That is, the conjugated diene polymer block D 1 It may be a non-hydrogenated conjugated diene polymer block or a hydrogenated conjugated diene polymer block.

[0071] Conjugated diene polymer block D 1 The monomer units other than the conjugated diene monomer units may be included. Examples of monomer units other than the conjugated diene monomer units include aromatic monovinyl monomers such as styrene and α-methylstyrene, α,β-unsaturated nitrile monomers, unsaturated carboxylic acid or anhydride monomers, unsaturated carboxylic acid ester monomers, and non-conjugated diene monomers. Conjugated diene polymer block D 1 The content of the monomer units other than the conjugated diene monomer units in the monomer unit is preferably 20% by mass or less, more preferably 10% by mass or less, particularly preferably substantially 0% by mass.

[0072] Conjugated diene polymer block D 1 The weight average molecular weight (Mw(D 1 )) is preferably in the range of 20,000 to 140,000, more preferably in the range of 25,000 to 120,000, and further preferably in the range of 30,000 to 100,000.

[0073] (1-1-3) by Ar 1 -D 1 The branch chain

[0074] The block copolymer A1 is composed of Ar 1 -D 1The branched chain represented by may be produced by using any coupling agent or may be produced without using a coupling agent. 1 -D 1 The side chain represented by may contain the residue of a coupling agent in each polymer block or between each polymer block, or may not contain the residue of a coupling agent. From the viewpoint of further improving the processability and crosslinking property of the adhesive composition and the adhesive properties of the obtained adhesive, it is preferred that Ar 1 -D 1 The branches shown are produced without the use of a coupling agent and do not contain residues of a coupling agent within or between the polymer blocks.

[0075] By Ar 1 -D 1 The weight average molecular weight (Mw(Ar 1 -D 1 )) is preferably in the range of 30,000 to 150,000, more preferably in the range of 35,000 to 130,000, and further preferably in the range of 40,000 to 110,000.

[0076] By Ar 1 -D 1 The molecular weight distribution (Mw / Mn) of the branched chains represented by is preferably within a range of 1.20 or less, more preferably within a range of 1.00 to 1.20, further preferably within a range of 1.00 to 1.18, particularly preferably within a range of 1.00 to 1.13, and particularly preferably within a range of 1.00 to 1.10.

[0077] (1-1-4) By D 2 The branch chain

[0078] The block copolymer A1 is composed of D 2 The branched chains represented are polymer block chains having conjugated diene monomer units as structural units.

[0079] As the conjugated diene polymer block D 2 The conjugated diene monomer of the conjugated diene monomer unit is not particularly limited as long as it is a conjugated diene compound, and examples thereof include 1,3-butadiene, isoprene (2-methyl-1,3-butadiene), 2,3-dimethyl-1,3-butadiene, 2-chloro-1,3-butadiene, 1,3-pentadiene, 1,3-hexadiene, etc. Among these conjugated diene monomers, 1,3-butadiene and / or isoprene are preferably used, and isoprene is particularly preferably used. Conjugated diene polymer block D 2 The isoprene polymer block is particularly preferred. 2The branched chains represented by the above-mentioned can further improve the processability and crosslinking properties of the adhesive composition and the adhesive properties of the obtained adhesive. 2 The side chains represented by can be used alone or in combination of two or more. 2 The unsaturated bonds of the side chains represented by are partially hydrogenated. 2 It may be a non-hydrogenated conjugated diene polymer block or a hydrogenated conjugated diene polymer block.

[0080] By D 2 The branched chain represented by may contain monomer units other than conjugated diene monomer units. Examples of monomer units other than conjugated diene monomer units include aromatic monovinyl monomers such as styrene and α-methylstyrene, α,β-unsaturated nitrile monomers, unsaturated carboxylic acid or anhydride monomers, unsaturated carboxylic acid ester monomers, and non-conjugated diene monomers. Conjugated diene polymer block D 2 The content of the monomer units other than the conjugated diene monomer units in the monomer unit is preferably 20% by mass or less, more preferably 10% by mass or less, particularly preferably substantially 0% by mass.

[0081] By D 2 The weight average molecular weight (Mw(D 2 )) is not particularly limited, but is preferably in the range of 20,000 to 140,000, more preferably in the range of 25,000 to 120,000, and further preferably in the range of 30,000 to 100,000.

[0082] (1-1-5) Residue X of a multifunctional coupling agent 1

[0083] As the residue X of the multifunctional coupling agent in the block copolymer A1 1 Any coupling agent that can react with Ar 1 -D 1 The branched chain represented by D 2 The branched chains represented by the coupling agent may be bonded to form a block copolymer having three or more branches in total.

[0084] Examples of the multifunctional coupling agent include silane compounds such as halogenated silanes such as tetrachlorosilane and tetrabromosilane, alkoxysilanes such as tetramethoxysilane and tetraethoxysilane, tin compounds such as tin halides such as tin tetrachloride, epoxy compounds such as polycarboxylates and epoxidized soybean oil, compounds having two or more radical polymerizable groups in the molecule, etc. Among these, compounds that can react with coupling agents to form a polymer are preferred, and compounds having two or more radical polymerizable groups in the molecule are more preferred.

[0085] As compounds having two or more radical polymerizable groups in the molecule, there can be mentioned, for example, free radical polymerizable aromatic compounds having an aromatic ring and two or more radical polymerizable groups in the molecule such as aromatic divinyl compounds, aromatic trivinyl compounds, and aromatic tetravinyl compounds; free radical polymerizable aliphatic compounds having an aliphatic group and two or more radical polymerizable groups in the molecule such as pentaerythritol tetraacrylate. In addition, as the free radical polymerizable group, a group containing a carbon-carbon double bond is preferred, and vinyl is more preferred.

[0086] Specific examples of aromatic divinyl compounds include divinylbenzene (DVB), divinyltoluene, divinylxylene, divinylanthracene, divinylnaphthalene, divinyldurene, 1,2-bis(4-vinylphenyl)ethane, etc. Specific examples of aromatic trivinyl compounds include trivinylbenzene, etc. Specific examples of aromatic tetravinyl compounds include tetravinylbenzene, etc.

[0087] In the present invention, the multifunctional coupling agent is preferably a compound having two or more free radical polymerizable groups in the molecule, more preferably a free radical polymerizable aromatic compound having an aromatic ring and two or more free radical polymerizable groups in the molecule, further preferably an aromatic divinyl compound, and particularly preferably divinylbenzene. By using these coupling agents, a block copolymer A1 having a branch number (m+n) within the above preferred range can be easily obtained, which can further improve the processability and crosslinking properties of the adhesive composition and the adhesive properties of the obtained adhesive.

[0088] (1-1-6) Block copolymer A1

[0089] In block copolymer A1, Ar 1 -D 1 The mass of the branched chain is expressed relative to that of D 2 The ratio of the mass of the branched chain (Ar 1 -D 1 ) / D 2 ) is not particularly limited, but is preferably 1.0 / 0.15 to 1.0 / 1.75, more preferably 1.0 / 0.20 to 1.0 / 1.25, further preferably 1.0 / 0.25 to 1.0 / 0.75, and particularly preferably 1.0 / 0.25 to 1.0 / 0.5. 1 -D 1 ) / D 2 ) is within the above range, the processability and crosslinking properties of the adhesive composition and the adhesive properties of the obtained adhesive can be further improved.

[0090] In block copolymer A1, Ar 1 -D 1 The conjugated diene polymer block D in the branched chain 1 The weight average molecular weight (Mw(D 1 )) Relative to D 2 The weight average molecular weight (Mw(D 2 )) ratio ((Mw(D 1 )) / (Mw(D 2 ))) is not particularly limited, but is preferably 1.0 / 0.3 to 1.0 / 1.1, more preferably 1.0 / 0.5 to 1.0 / 1.07, further preferably 1.0 / 0.7 to 1.0 / 1.05, and particularly preferably 1.0 / 0.9 to 1.0 / 1.03. 1 )) / (Mw(D 2 ))) is within the above range, the processability and cross-linking properties of the adhesive composition and the adhesive properties of the obtained adhesive can be further improved.

[0091] The weight average molecular weight (MwA1) of the block copolymer A1 is preferably within the range of 300,000 to 800,000, more preferably within the range of 330,000 to 700,000, further preferably within the range of 360,000 to 650,000, particularly preferably within the range of 380,000 to 600,000, and most preferably within the range of 400,000 to 550,000. By setting the weight average molecular weight (MwA1) of the block copolymer A1 within the above range, the processability and crosslinking properties of the adhesive composition and the adhesive properties of the obtained adhesive can be further improved.

[0092] The molecular weight distribution (Mw / Mn) of the block copolymer A1 is preferably 1.40 or less, more preferably 1.00 to 1.30, further preferably 1.00 to 1.20, particularly preferably 1.00 to 1.18, and most preferably 1.00 to 1.16. By setting the molecular weight distribution (Mw / Mn) of the block copolymer A1 to the above range, the processability and crosslinking properties of the adhesive composition and the adhesive properties of the obtained adhesive can be further improved.

[0093] The content of the aromatic monovinyl monomer unit of the block copolymer A1 (the proportion of the aromatic monovinyl monomer unit relative to all monomer units constituting the block copolymer A1) is preferably in the range of 5 to 40% by mass, more preferably in the range of 9 to 35% by mass, further preferably in the range of 12 to 30% by mass, particularly preferably in the range of 15 to 28% by mass, and most preferably in the range of 18 to 26% by mass. By making the content of the aromatic monovinyl monomer unit of the block copolymer A1 within the above range, the processability and crosslinking properties of the adhesive composition and the adhesive properties of the obtained adhesive can be further improved.

[0094] The vinyl bond content in the conjugated diene monomer units of the block copolymer A1 (the ratio of 1,2-vinyl bonds and 3,4-vinyl bonds in all the conjugated diene monomer units constituting the block copolymer A1) is preferably in the range of 1 to 20 mass %, more preferably in the range of 1 to 15 mass %, and particularly preferably in the range of 1 to 10 mass %.

[0095] (1-2) Block copolymer A2

[0096] The block copolymer composition used in the present invention may contain the block copolymer A2 described below instead of the block copolymer A1, or may contain the block copolymer A1 and the block copolymer A2.

[0097] The block copolymer A2 is a block copolymer represented by the following general formula (2):

[0098]

[0099] (In the general formula (2), Ar is an aromatic monovinyl polymer block, D is a conjugated diene polymer block, p is an integer of 3 or more, and X is a residue of a polyfunctional coupling agent.)

[0100] In general formula (2), Ar-D is a branched chain bonded to X, and p is the number of branches represented by Ar-D bonded to X, thus representing the number of branches of block copolymer A2. In addition, Ar is an aromatic monovinyl polymer block, and D is a conjugated diene polymer block.

[0101] In general formula (2), p is an integer greater than or equal to 3. That is, block copolymer A2 has a branched structure consisting of three or more branches, and the branches are branches represented by Ar-D (a diblock chain including an aromatic monovinyl polymer block and a conjugated diene polymer block).

[0102] In the general formula (2), p is an integer greater than 3, and is not particularly limited, but is preferably an integer from 4 to 20, more preferably an integer from 5 to 15, and still more preferably an integer from 6 to 10. By making p within the above range, the processability and crosslinking properties of the adhesive composition and the adhesive properties of the obtained adhesive can be further improved. p can be adjusted by adjusting the structure of the side chain represented by Ar-D, the coupling conditions (such as the type and amount of the multifunctional coupling agent used).

[0103] The block copolymer A2 may be composed of only one type of block copolymer having substantially a single structure, or may be composed of two or more types of block copolymers having substantially different structures.

[0104] In addition, block copolymer A2 can be a mixture of block copolymers with different p. When the average molecular weight of block copolymer A2 is obtained by using the high performance liquid chromatography described later to calculate p, what is calculated is the average value of p of multiple block copolymers in the mixture, therefore, these calculated values ​​exist and may not be the possibility of integers, and in the present invention, the integer closest to the calculated value can be designated as p.

[0105] (1-2-1) Aromatic monovinyl polymer block Ar

[0106] The aromatic monovinyl polymer block Ar constituting the block copolymer A2 is a polymer block having an aromatic monovinyl monomer unit as a structural unit. As the aromatic monovinyl monomer used to constitute the aromatic monovinyl polymer block Ar, the aromatic monovinyl monomers used to constitute the aromatic monovinyl polymer block Ar can be exemplified. 1 The aromatic monovinyl monomer of the aromatic monovinyl monomer unit is the same aromatic monovinyl monomer, and styrene is particularly preferred. The aromatic monovinyl monomer can be used alone or in combination of two or more kinds in the aromatic monovinyl polymer block Ar.

[0107] The aromatic monovinyl polymer block Ar may contain monomer units other than the aromatic monovinyl monomer units. As monomers constituting monomer units other than the aromatic monovinyl monomer units, examples thereof include conjugated diene monomers such as 1,3-butadiene, isoprene (2-methyl-1,3-butadiene), α,β-unsaturated nitrile monomers, unsaturated carboxylic acid or anhydride monomers, unsaturated carboxylic acid ester monomers, and non-conjugated diene monomers. The content of monomer units other than the aromatic monovinyl monomer units in the aromatic monovinyl polymer block Ar is preferably 20% by mass or less, more preferably 10% by mass or less, and particularly preferably substantially 0% by mass.

[0108] The weight average molecular weight (Mw(Ar)) of the aromatic monovinyl polymer block Ar is not particularly limited, and can be in the range of 7,000 to 18,000, preferably in the range of 7,500 to 17,000, and more preferably in the range of 8,000 to 16,000.

[0109] (1-2-2) Conjugated diene polymer block D

[0110] The conjugated diene polymer block D constituting the block copolymer A2 is a polymer block having a conjugated diene monomer unit as a structural unit. Examples of the conjugated diene monomers used to constitute the conjugated diene polymer block D include the same monomers as those used to constitute the conjugated diene polymer block D of the block copolymer A1. 1 The conjugated diene monomers of the conjugated diene monomer units are the same as the conjugated diene monomers, and 1,3-butadiene and / or isoprene are particularly preferably used, and isoprene is particularly preferably used. The conjugated diene polymer block D is particularly preferably an isoprene polymer block. By using isoprene monomer units to constitute the conjugated diene polymer block D, the processability and crosslinking properties of the adhesive composition and the adhesive properties of the obtained adhesive can be further improved. These conjugated diene monomers can be used alone or in combination of two or more in the conjugated diene polymer block D. Furthermore, a part of the unsaturated bonds of the conjugated diene polymer block D can be hydrogenated. That is, the conjugated diene polymer block D can be an unhydrogenated conjugated diene polymer block or a hydrogenated conjugated diene polymer block.

[0111] The conjugated diene polymer block D may contain monomer units other than the conjugated diene monomer units. As monomers constituting monomer units other than the conjugated diene monomer units, there may be mentioned aromatic monovinyl monomers such as styrene and α-methylstyrene, α,β-unsaturated nitrile monomers, unsaturated carboxylic acids or anhydride monomers, unsaturated carboxylic acid ester monomers, and non-conjugated diene monomers. The content of monomer units other than the conjugated diene monomer units in the conjugated diene polymer block D is preferably 20% by mass or less, more preferably 10% by mass or less, and particularly preferably substantially 0% by mass.

[0112] The weight average molecular weight (Mw(D)) of the conjugated diene polymer block D is preferably in the range of 20,000 to 140,000, more preferably in the range of 25,000 to 120,000, and further preferably in the range of 30,000 to 100,000.

[0113] (1-2-3) Branched chain represented by Ar-D

[0114] The side chain represented by Ar-D constituting the block copolymer A2 can be manufactured using any coupling agent, in addition, it can also be manufactured without using a coupling agent. That is, the side chain represented by Ar-D can include the residue of a coupling agent in each polymer block or between each polymer block, in addition, it is also possible not to include the residue of a coupling agent. From the viewpoint of being able to further improve the processability and crosslinking of the adhesive composition and the adhesive properties of the obtained adhesive, the side chain preferably represented by Ar-D is manufactured without using a coupling agent and does not include the residue of a coupling agent in each polymer block and between each polymer block.

[0115] The weight average molecular weight (Mw(Ar-D)) of the branched chain represented by Ar-D is preferably in the range of 30,000 to 150,000, more preferably in the range of 35,000 to 130,000, and further preferably in the range of 40,000 to 110,000.

[0116] The molecular weight distribution (Mw / Mn) of the branch represented by Ar-D is preferably within a range of 1.20 or less, more preferably within a range of 1.00 to 1.20, further preferably within a range of 1.00 to 1.18, particularly preferably within a range of 1.00 to 1.13, and particularly preferably within a range of 1.00 to 1.10.

[0117] (1-2-4) Residue X of a multifunctional coupling agent

[0118] The coupling agent forming the residue X of the polyfunctional coupling agent in the block copolymer A2 may be any coupling agent as long as it can bond to the branched chain represented by Ar-D to form a block copolymer having three or more branches in total.

[0119] Examples of the polyfunctional coupling agent that forms the residue X of the polyfunctional coupling agent include the polyfunctional coupling agent residue X in the block copolymer A1. 1 The coupling agent described above is a coupling agent. The multifunctional coupling agent is preferably a compound having two or more free radical polymerizable groups in the molecule, more preferably a free radical polymerizable aromatic compound having an aromatic ring and two or more free radical polymerizable groups in the molecule, further preferably an aromatic divinyl compound, and particularly preferably divinylbenzene. By using these coupling agents, a block copolymer A2 having a branch number (p) within the above-mentioned preferred range can be easily obtained, which can further improve the processability and crosslinking properties of the adhesive composition and the adhesive properties of the obtained adhesive.

[0120] (1-2-5) Block copolymer A2

[0121] The weight average molecular weight (MwA2) of the block copolymer A2 is preferably in the range of 300000 to 800000, more preferably in the range of 340000 to 750000, further preferably in the range of 380000 to 700000, particularly preferably in the range of 420000 to 650000, and most preferably in the range of 450000 to 600000. By setting the weight average molecular weight (MwA2) of the block copolymer A2 in the above range, the processability and crosslinking properties of the adhesive composition and the adhesive properties of the obtained adhesive can be further improved.

[0122] The molecular weight distribution (Mw / Mn) of the block copolymer A2 is preferably 1.40 or less, more preferably 1.00 to 1.30, further preferably 1.00 to 1.20, particularly preferably 1.00 to 1.18, and most preferably 1.00 to 1.16. By setting the molecular weight distribution (Mw / Mn) of the block copolymer A2 to the above range, the processability and crosslinking properties of the adhesive composition and the adhesive properties of the obtained adhesive can be further improved.

[0123] The content of the aromatic monovinyl monomer unit of the block copolymer A2 (the proportion of the aromatic monovinyl monomer unit relative to all monomer units constituting the block copolymer A2) is preferably in the range of 5 to 40% by mass, more preferably in the range of 9 to 35% by mass, further preferably in the range of 12 to 30% by mass, particularly preferably in the range of 15 to 28% by mass, and most preferably in the range of 18 to 26% by mass. By making the content of the aromatic monovinyl monomer unit of the block copolymer A2 within the above range, the processability and crosslinking properties of the adhesive composition and the adhesive properties of the obtained adhesive can be further improved.

[0124] The vinyl bond content in the conjugated diene monomer units of the block copolymer A2 (the proportion of 1,2-vinyl bonds and 3,4-vinyl bonds in all the conjugated diene monomer units constituting the block copolymer A2) is preferably in the range of 1 to 20 mass %, more preferably in the range of 1 to 15 mass %, and particularly preferably in the range of 1 to 10 mass %.

[0125] (1-3) Diblock copolymer B

[0126] The block copolymer composition used in the present invention may contain a diblock copolymer B in addition to the block copolymer A1 or the block copolymer A2.

[0127] The diblock copolymer B is a block copolymer represented by the following general formula (3):

[0128]

[0129] (In formula (3), Ar3 is an aromatic monovinyl polymer block, D 3 It is a conjugated diene polymer block. )

[0130] When the block copolymer composition contains the block copolymer A1, the diblock copolymer B generally has the same structure as the Ar constituting the block copolymer A1. 1 -D 1 The same structure of the branched chains represented by may also have different structures. In this case, for the aromatic monovinyl polymer block Ar constituting the diblock copolymer B 3 and conjugated diene polymer block D 3 , can be the aromatic monovinyl polymer block Ar in the block copolymer A1 1 and conjugated diene polymer block D 1 The same contents and preferred embodiments are also the same. In addition, according to the method for producing the block copolymer A1 described later, the structure of the diblock copolymer B can generally be the same as that of the Ar constituting the block copolymer A1. 1 -D 1 The same structure as the branched chain is represented.

[0131] When the block copolymer composition contains block copolymer A2, diblock copolymer B generally has the same structure as the branched chain represented by Ar-D constituting block copolymer A2, but may have a different structure. In this case, for the aromatic monovinyl polymer block Ar constituting diblock copolymer B, 3 and conjugated diene polymer block D 3 , can be the same as the aromatic monovinyl polymer block Ar and the conjugated diene polymer block D in the block copolymer A2, and the preferred mode is also the same. In addition, according to the manufacturing method of the block copolymer A2 described later, the structure of the diblock copolymer B can usually be the same structure as the side chain represented by Ar-D constituting the block copolymer A2.

[0132] The diblock copolymer B may be produced using any coupling agent or may be produced without using a coupling agent, but preferably contains no coupling agent residue in each polymer block or between each polymer block.

[0133] The weight average molecular weight (MwB) of the diblock copolymer B is preferably within a range of 30,000 to 150,000, more preferably within a range of 35,000 to 130,000, and even more preferably within a range of 40,000 to 110,000.

[0134] The molecular weight distribution (Mw / Mn) of the diblock copolymer B is preferably within a range of 1.20 or less, more preferably within a range of 1.00 to 1.20, further preferably within a range of 1.00 to 1.18, particularly preferably within a range of 1.00 to 1.13, and particularly preferably within a range of 1.00 to 1.10.

[0135] The content of the aromatic monovinyl monomer unit in the diblock copolymer B (the proportion of the aromatic monovinyl monomer unit relative to all the monomer units constituting the diblock copolymer B) is preferably in the range of 5 to 40 mass %, more preferably in the range of 9 to 35 mass %, further preferably in the range of 12 to 30 mass %, particularly preferably in the range of 15 to 28 mass %, and most preferably in the range of 18 to 26 mass %.

[0136] The vinyl bond content in the conjugated diene monomer units of the diblock copolymer B (the proportion of 1,2-vinyl bonds and 3,4-vinyl bonds in all the conjugated diene monomer units constituting the diblock copolymer B) is preferably in the range of 1 to 20 mass %, more preferably in the range of 1 to 15 mass %, and particularly preferably in the range of 1 to 10 mass %.

[0137] The diblock copolymer B constituting the block copolymer composition used in the present invention may be composed of only one type of diblock copolymer B having substantially a single structure, or may be composed of two or more types of diblock copolymers B having substantially different structures.

[0138] (1-4) Polymer C

[0139] The block copolymer composition used in the present invention may contain polymer C in addition to block copolymer A1 or block copolymer A2 and diblock copolymer B used as needed. In one embodiment of the present invention, the block copolymer composition may consist of only block copolymer A1, block copolymer A2, diblock copolymer B and polymer C, or only block copolymer A1, diblock copolymer B and polymer C, or only block copolymer A2, diblock copolymer B and polymer C.

[0140] The polymer C is a conjugated diene polymer having a conjugated diene monomer unit as a structural unit represented by the following general formula (4):

[0141]

[0142] (In formula (4), D 4 It is a conjugated diene polymer block. )

[0143] The polymer C is a conjugated diene polymer having a conjugated diene monomer unit as a structural unit. Examples of the conjugated diene monomer used to constitute the conjugated diene monomer unit of the polymer C include the conjugated diene polymer block D used to constitute the block copolymer A1. 2 The conjugated diene monomers described above are preferably 1,3-butadiene and / or isoprene, and isoprene is particularly preferred. Conjugated diene polymer block D 4 Isoprene polymer blocks are particularly preferred. By making polymer C consist of isoprene monomer units, the processability and crosslinking properties of the adhesive composition and the adhesive properties of the obtained adhesive can be further improved. These conjugated diene monomers can be used alone or in combination of two or more in polymer C. Furthermore, a part of the unsaturated bonds of polymer C can be hydrogenated. That is, conjugated diene polymer block D 4 It may be a non-hydrogenated conjugated diene polymer block or a hydrogenated conjugated diene polymer block.

[0144] Polymer C may contain monomer units other than conjugated diene monomer units. As monomers constituting monomer units other than conjugated diene monomer units, aromatic monovinyl monomers such as styrene and α-methylstyrene, α,β-unsaturated nitrile monomers, unsaturated carboxylic acids or anhydride monomers, unsaturated carboxylic acid ester monomers, and non-conjugated diene monomers can be cited. The content of monomer units other than conjugated diene monomer units in polymer C is preferably 20% by mass or less, more preferably 10% by mass or less, and particularly preferably substantially 0% by mass.

[0145] When the block copolymer composition contains the block copolymer A1, the polymer C usually has a conjugated diene polymer block D constituting the block copolymer A1. 2 The same structure may have different structures. When the block copolymer composition contains the block copolymer A1, the polymer C may be a polymer having the same structure as the conjugated diene polymer block D in the block copolymer A1. 2 The same contents and preferred embodiments are also the same. In addition, according to the method for producing the block copolymer A1 described below, the structure of the polymer C can usually be a conjugated diene polymer block D constituting the block copolymer A1. 2 Same structure.

[0146] The weight average molecular weight (MwC) of the polymer C is preferably in the range of 20,000 to 140,000, more preferably in the range of 25,000 to 120,000, and even more preferably in the range of 30,000 to 100,000.

[0147] The molecular weight distribution (Mw / Mn) of polymer C is preferably within a range of 1.20 or less, more preferably within a range of 1.00 to 1.20, further preferably within a range of 1.00 to 1.18, particularly preferably within a range of 1.00 to 1.13, and particularly preferably within a range of 1.00 to 1.10. By setting the molecular weight distribution (Mw / Mn) of polymer C within the above range, the processability and crosslinking properties of the adhesive composition and the adhesive properties of the obtained adhesive can be further improved.

[0148] The vinyl bond content in the conjugated diene monomer units of the polymer C (the ratio of 1,2-vinyl bonds and 3,4-vinyl bonds in all the conjugated diene monomer units constituting the polymer C) is preferably in the range of 1 to 20 mass %, more preferably in the range of 1 to 15 mass %, and particularly preferably in the range of 1 to 10 mass %.

[0149] The polymer C may be composed of only one type of polymer C having substantially a single structure, or may be composed of two or more types of polymers C having substantially different structures.

[0150] (1-5) Block copolymer composition

[0151] The block copolymer composition used in the present invention contains the above-mentioned block copolymer A1 or block copolymer A2 and, if necessary, a diblock copolymer B and a polymer C, and the weight average molecular weight (Mw) of the entire block copolymer composition is 300,000 to 800,000.

[0152] In the present invention, the weight average molecular weight (Mw) of the block copolymer composition as a whole refers to the weight average molecular weight (Mw) of the polymer components including the conjugated diene polymer block constituting the block copolymer composition as a whole. For example, when the block copolymer composition is composed of block copolymer A1, block copolymer A2, diblock copolymer B and polymer C, the weight average molecular weight (Mw) of the block copolymer composition as a whole refers to the weight average molecular weight (Mw) of the polymer components as a whole composed of block copolymer A1, block copolymer A2, diblock copolymer B and polymer C.

[0153] The weight average molecular weight (Mw) of the block copolymer composition used in the present invention is in the range of 300,000 to 800,000. By making the weight average molecular weight (Mw) of the block copolymer composition as a whole within the above range, the adhesive composition of the present invention has excellent processability and can form an adhesive composition having excellent adhesive properties. From the viewpoint of being able to further improve the processability and crosslinking of the adhesive composition, and the adhesive properties of the obtained adhesive, the weight average molecular weight (Mw) of the block copolymer composition as a whole is preferably in the range of 320,000 to 750,000, more preferably in the range of 340,000 to 700,000, further preferably in the range of 360,000 to 650,000, and particularly preferably in the range of 380,000 to 600,000.

[0154] The molecular weight distribution of the entire block copolymer composition, represented by the ratio (Mw / Mn) of the weight average molecular weight (Mw) to the number average molecular weight (Mn), is preferably in the range of 1.01 to 2.50, more preferably in the range of 1.02 to 2.20, and even more preferably in the range of 1.02 to 2.0.

[0155] When the block copolymer composition contains the block copolymer A1, the content of the block copolymer A1 in the block copolymer composition is preferably in the range of 10% by mass or more, more preferably in the range of 40% by mass or more, further preferably in the range of 60% by mass or more, particularly preferably in the range of 80 to 99% by mass, and most preferably in the range of 90 to 98% by mass, when the total mass of the block copolymer composition is 100% by mass. By making the content of the block copolymer A1 in the block copolymer composition within the above range, the processability and crosslinking properties of the adhesive composition and the adhesive properties of the obtained adhesive can be further improved.

[0156] When the block copolymer composition contains the block copolymer A2, the content of the block copolymer A2 in the block copolymer composition is preferably in the range of 10% by mass or more, more preferably in the range of 40% by mass or more, further preferably in the range of 60% by mass or more, particularly preferably in the range of 80 to 99% by mass, and most preferably in the range of 90 to 98% by mass, when the total mass of the block copolymer composition is 100% by mass. By making the content of the block copolymer A2 in the block copolymer composition in the above range, the processability and crosslinking properties of the adhesive composition and the adhesive properties of the obtained adhesive can be further improved.

[0157] The total content of block copolymer A1 and block copolymer A2 in the block copolymer composition is preferably in the range of 10% by mass or more, more preferably in the range of 40% by mass or more, further preferably in the range of 60% by mass or more, particularly preferably in the range of 80 to 99% by mass, and most preferably in the range of 90 to 98% by mass, when the total mass of the block copolymer composition is 100% by mass. By making the total content of block copolymer A1 and block copolymer A2 in the block copolymer composition within the above range, the processability and crosslinking properties of the adhesive composition and the adhesive properties of the obtained adhesive can be further improved.

[0158] The content of the diblock copolymer B in the block copolymer composition is preferably within a range of 60% by mass or less, more preferably within a range of 40% by mass or less, further preferably within a range of 20% by mass or less, particularly preferably within a range of 0.5 to 15% by mass, and most preferably within a range of 1 to 10% by mass, when the total mass of the block copolymer composition is 100% by mass. By making the content of the diblock copolymer B in the block copolymer composition within the above range, the processability and crosslinking properties of the adhesive composition and the adhesive properties of the obtained adhesive can be further improved.

[0159] The content of polymer C in the block copolymer composition is preferably within the range of 60% by mass or less, more preferably within the range of 40% by mass or less, further preferably within the range of 20% by mass or less, particularly preferably within the range of 0.5 to 15% by mass, and most preferably within the range of 1 to 10% by mass, when the total mass of the block copolymer composition is 100% by mass. By making the content of polymer C in the block copolymer composition within the above range, the processability and crosslinking properties of the adhesive composition and the adhesive properties of the obtained adhesive can be further improved.

[0160] The total content of the diblock copolymer B and the polymer C in the block copolymer composition is preferably within the range of 90% by mass or less, more preferably within the range of 60% by mass or less, further preferably within the range of 40% by mass or less, particularly preferably within the range of 1 to 20% by mass, and most preferably within the range of 2 to 10% by mass, when the total mass of the block copolymer composition is 100% by mass. By making the total content of the diblock copolymer B and the polymer C in the block copolymer composition within the above range, the processability and crosslinking properties of the adhesive composition and the adhesive properties of the obtained adhesive can be further improved.

[0161] When the block copolymer composition contains the block copolymer A1, the content ratio of the block copolymer A1, the diblock copolymer B and the polymer C in the block copolymer composition (content of the block copolymer A1 / content of the diblock copolymer B / content of the polymer C) is preferably 10 to 100 / 0 to 60 / 0 to 60, more preferably 40 to 100 / 0 to 40 / 0 to 40, further preferably 60 to 100 / 0 to 20 / 0 to 20, particularly preferably 80 to 99 / 0.5 to 15 / 0.5 to 15, and most preferably 90 to 98 / 1 to 10 / 1 to 10.

[0162] When the block copolymer composition contains the block copolymer A2, the content ratio of the block copolymer A2, the diblock copolymer B and the polymer C in the block copolymer composition (the content of the block copolymer A2 / the content of the diblock copolymer B / the content of the polymer C) is preferably 10 to 100 / 0 to 60 / 0 to 60, more preferably 40 to 100 / 0 to 40 / 0 to 40, further preferably 60 to 100 / 0 to 20 / 0 to 20, particularly preferably 80 to 99 / 0.5 to 15 / 0.5 to 15, and most preferably 90 to 98 / 1 to 10 / 1 to 10, on a mass basis.

[0163] The total content of the block copolymer A1 and the block copolymer A2, the content of the diblock copolymer B, and the content ratio of the polymer C (total content of the block copolymer A1 and the block copolymer A2 / content of the diblock copolymer B / content of the polymer C) in the block copolymer composition is preferably 10 to 100 / 0 to 60 / 0 to 60, more preferably 40 to 100 / 0 to 40 / 0 to 40, further preferably 60 to 100 / 0 to 20 / 0 to 20, particularly preferably 80 to 99 / 0.5 to 15 / 0.5 to 15, and most preferably 90 to 98 / 1 to 10 / 1 to 10.

[0164] The content of the aromatic monovinyl monomer unit in the block copolymer composition, i.e., the proportion of the aromatic monovinyl monomer unit relative to the total amount of the block copolymer composition, i.e., the proportion of the aromatic monovinyl monomer unit relative to the entire block copolymer component of the block copolymer composition (hereinafter, sometimes referred to as "the overall aromatic monovinyl monomer unit content") is preferably in the range of 5 to 40% by mass, more preferably in the range of 9 to 35% by mass, further preferably in the range of 12 to 30% by mass, particularly preferably in the range of 15 to 28% by mass, and most preferably in the range of 18 to 26% by mass. By making the content of the overall aromatic monovinyl monomer unit within the above range, the processability and crosslinking properties of the adhesive composition and the adhesive properties of the obtained adhesive can be further improved.

[0165] The overall aromatic monovinyl monomer unit content can be easily adjusted by adjusting the amount of each polymer to be added, taking into account the content of the aromatic monovinyl monomer unit of each polymer constituting the block copolymer composition. In addition, in the case where all polymer components constituting the block copolymer composition are only composed of aromatic monovinyl monomer units and conjugated diene monomer units, if the polymer components are subjected to ozone decomposition according to the method described in Rubber Chem. Technol., 45, 1295 (1972), followed by reduction with lithium aluminum hydride, the conjugated diene monomer unit can be partially decomposed, and only the aromatic monovinyl monomer unit portion can be extracted, so the overall aromatic monovinyl monomer unit content can be easily measured.

[0166] The vinyl bond content in the conjugated diene monomer units in the block copolymer composition (the ratio of 1,2-vinyl bonds and 3,4-vinyl bonds in all the conjugated diene monomer units constituting the block copolymer composition) is preferably in the range of 1 to 20 mass %, more preferably in the range of 1 to 15 mass %, and particularly preferably in the range of 1 to 10 mass %.

[0167] The A-type hardness of the block copolymer composition is preferably 25 to 65, more preferably 26 to 64, and further preferably 27 to 63. By setting the A-type hardness of the block copolymer composition to the above range, the processability of the adhesive composition can be further improved. The A-type hardness is a value measured using a durometer hardness tester (A-type) in accordance with JIS K6253.

[0168] The content of the block copolymer composition in the adhesive composition is preferably 90 to 99.95% by mass, more preferably 93 to 99.9% by mass, further preferably 96 to 99.85% by mass, particularly preferably 98 to 99.8% by mass, and most preferably 99 to 99.75% by mass, which can further improve the processability and crosslinking properties of the adhesive composition and the adhesive properties of the resulting adhesive.

[0169] 2. Alkyl radical scavengers

[0170] The adhesive composition of the present invention contains an alkyl radical scavenger in addition to the above-mentioned block copolymer composition.

[0171] The alkyl radical scavenger used in the present invention is a compound that captures alkyl radicals generated from polymer components. The alkyl radicals may be alkyl radicals generated by cleavage of the main chain or side chain of a polymer component such as a block copolymer by heat, light or the like.

[0172] As an alkyl radical scavenger, a compound containing an acryloyl or methacryloyl group in the molecule is preferred, and a compound containing an acryloyl or methacryloyl group in the molecule and further containing a hydroxyphenyl group is more preferred. In addition, the hydroxyphenyl group can be a hydroxyphenyl group in which at least one of the two ortho positions of the hydroxyl group bonded to the benzene ring is substituted by a group containing two or more carbon atoms. As an alkyl radical scavenger, it is further preferred to be selected from at least one of 2-[1-(2-hydroxy-3,5-di-tert-amylphenyl)ethyl]-4,6-di-tert-amylphenyl acrylate and 2-tert-butyl-6-(3-tert-butyl-2-hydroxy-5-methylbenzyl)-4-methylphenyl acrylate. These can be used alone or in combination of two or more.

[0173] The content of the alkyl radical scavenger in the adhesive composition is 0.05 to 2 parts by mass relative to 100 parts by mass of the block copolymer composition in the adhesive composition. When the content of the alkyl radical scavenger is too small, the processability is poor, and processing (such as biaxial extrusion processing) with strong shear stress cannot be well implemented, and the hot melt processability of the obtained hot melt adhesive composition is also poor. On the other hand, when the content of the alkyl radical scavenger is too large, the crosslinking property is poor, and the adhesive properties of the obtained adhesive are also poor.

[0174] In addition, in the present invention, “the content of the alkyl radical scavenger is 0.05 to 2 parts by mass relative to 100 parts by mass of the block copolymer composition” means “the content of the alkyl radical scavenger is 0.05 to 2 parts by mass relative to 100 parts by mass of the total content of the polymer component (block copolymer composition) containing a conjugated diene polymer block in the adhesive composition”. For example, when the polymer component (block copolymer composition) containing a conjugated diene polymer block in the adhesive composition is composed of only block copolymer A1, block copolymer A2, diblock copolymer B and polymer C, “the content of the alkyl radical scavenger is 0.05 to 2 parts by mass relative to 100 parts by mass of the block copolymer composition” means “the content of the alkyl radical scavenger is 0.05 to 2 parts by mass relative to 100 parts by mass of the total content of the block copolymer A1, block copolymer A2, diblock copolymer B and polymer C in the adhesive composition”. Hereinafter, regarding the content of each component other than the alkyl radical scavenger, the description of "the content relative to 100 parts by mass of the block copolymer composition" can be replaced with "relative to 100 parts by mass of the total content of the polymer component (block copolymer composition) containing the conjugated diene polymer block".

[0175] The content of the alkyl radical scavenger in the adhesive composition is not particularly limited as long as it is 0.05 to 2 parts by mass relative to 100 parts by mass of the block copolymer composition in the adhesive composition, and is preferably 0.1 to 1.5 parts by mass, more preferably 0.15 to 1 part by mass, further preferably 0.18 to 0.8 parts by mass, and particularly preferably 0.2 to 0.5 parts by mass relative to 100 parts by mass of the block copolymer composition. By making the content of the alkyl radical scavenger in the adhesive composition within the above range, the processability and crosslinking properties of the adhesive composition and the adhesive properties of the obtained adhesive can be further improved.

[0176] 3. Antioxidants

[0177] The adhesive composition of the present invention preferably contains an antioxidant in addition to the block copolymer composition and the alkyl radical scavenger. Examples of the antioxidant include hindered phenol antioxidants, phosphorus antioxidants, sulfur antioxidants, and benzofuranone antioxidants. The adhesive composition of the present invention may consist only of the block copolymer composition, the alkyl radical scavenger, and the antioxidant.

[0178] (3-1) Hindered phenol antioxidants

[0179] Examples of the hindered phenol-based antioxidant include compounds having a hydroxyphenyl group in which at least one of two ortho positions of a hydroxy group bonded to a benzene ring is substituted with a group containing two or more carbon atoms.

[0180] Specific examples of hindered phenol antioxidants include pentaerythritol tetrakis[3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate], 4-[[4,6-bis(octylthio)-1,3,5-triazin-2-yl]amino]-2,6-di-tert-butylphenol, 2,6-di-tert-butyl-p-cresol, stearyl 3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate, 2,4,6-tris(3′,5′-di-tert-butyl-4′-hydroxybenzyl)mesitylene, tetrakis(methylene-3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate)methane, and 2,6-di-tert-butyl-4-((4,6-bis(octylthio)-1,3,5-triazin-2-yl)amino)-phenol. Among these, pentaerythritol tetrakis[3-[3,5-di(tert-butyl)-4-hydroxyphenyl]propionate] and 4-[[4,6-bis(octylthio)-1,3,5-triazin-2-yl]amino]-2,6-di-tert-butylphenol are preferred, and pentaerythritol tetrakis[3-[3,5-di(tert-butyl)-4-hydroxyphenyl]propionate] and 4-[[4,6-bis(octylthio)-1,3,5-triazin-2-yl]amino]-2,6-di-tert-butylphenol are more preferred.

[0181] The content of the hindered phenol antioxidant in the adhesive composition is not particularly limited, but is preferably 0 to 5 parts by mass, more preferably 0.01 to 2 parts by mass, further preferably 0.02 to 1 part by mass, particularly preferably 0.05 to 0.5 parts by mass, and most preferably 0.1 to 0.3 parts by mass, relative to 100 parts by mass of the block copolymer composition in the adhesive composition. By setting the content of the hindered phenol antioxidant within the above range, the adhesive properties of the obtained adhesive can be further improved.

[0182] (3-2) Phosphorus antioxidants

[0183] Examples of the phosphorus-based antioxidant include monophosphite-based compounds and diphosphite-based compounds.

[0184] Specific examples of the monophosphite-based compounds include triphenyl phosphite, diphenyl isodecyl phosphite, phenyl diisodecyl phosphite, tris(nonylphenyl)phosphite, tris(dinonylphenyl)phosphite, tris(2,4-di-tert-butylphenyl)phosphite, tris(2-tert-butyl-4-methylphenyl)phosphite, tris(cyclohexylphenyl)phosphite, 2,2-methylenebis(4,6-di-tert-butylphenyl)octylphosphite, 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide, 10-(3,5-di-tert-butyl-4-hydroxybenzyl)-9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide, and 10-decyloxy-9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide.

[0185] Specific examples of diphosphite compounds include 4,4′-butylene-bis(3-methyl-6-tert-butylphenyl-di-tridecylphosphite), 4,4′-isopropylidene-bis(phenyl-dialkyl (C12-C15)phosphite), 4,4′-isopropylidene-bis(diphenylmonoalkyl (C12-C15)phosphite), 1,1,3-tris(2-methyl-4-di-tridecylphosphite-5-tert-butyl diphosphite compounds such as cyclopentanetetraylbis(isodecyl phosphite), cyclopentanetetraylbis(nonylphenyl phosphite), cyclopentanetetraylbis(2,4-di-tert-butylphenyl phosphite), cyclopentanetetraylbis(2,4-dimethylphenyl phosphite), and cyclopentanetetraylbis(2,6-di-tert-butylphenyl phosphite).

[0186] Among these, monophosphite compounds are preferred, and tris(nonylphenyl)phosphite, tris(dinonylphenyl)phosphite, and tris(2,4-di-tert-butylphenyl)phosphite are more preferred.

[0187] The content of the phosphorus antioxidant in the adhesive composition is not particularly limited, but is preferably 0 to 5 parts by mass, more preferably 0.01 to 2 parts by mass, further preferably 0.02 to 1 part by mass, particularly preferably 0.05 to 0.5 parts by mass, and most preferably 0.1 to 0.3 parts by mass, relative to 100 parts by mass of the block copolymer composition in the adhesive composition. By setting the content of the phosphorus antioxidant to the above range, the adhesive properties of the obtained adhesive can be further improved.

[0188] (3-3) Sulfur-based antioxidants

[0189] Examples of the sulfur-based antioxidant include dilauryl 3,3-thiodipropionate, dimyristyl 3,3′-thiodipropionate, distearyl 3,3-thiodipropionate, laurylstearyl 3,3-thiodipropionate, pentaerythritol tetrakis(β-laurylthiopropionate), and 3,9-bis(2-dodecylthioethyl)-2,4,8,10-tetraoxaspiro[5,5]undecane.

[0190] The content of the sulfur-based antioxidant in the adhesive composition is not particularly limited, but is preferably 0 to 5 parts by mass, more preferably 0.01 to 2 parts by mass, further preferably 0.02 to 1 part by mass, particularly preferably 0.05 to 0.5 parts by mass, and most preferably 0.1 to 0.3 parts by mass, relative to 100 parts by mass of the block copolymer composition in the adhesive composition. By setting the content of the sulfur-based antioxidant to the above range, the adhesive properties of the obtained adhesive can be further improved.

[0191] (3-4) Benzofuranone antioxidants

[0192] As a benzofuranone antioxidant, any compound having a benzofuranone skeleton is sufficient, and preferably a 3-arylbenzofuran-2-one having a benzofuranone skeleton and an aryl group as a substituent on the side chain of the furan ring. As a specific example of a benzofuranone antioxidant, 5,7-di-tert-butyl-3-(3,4-dimethylphenyl)-3H-benzofuran-2-one and the like can be cited.

[0193] The content of the benzofuranone antioxidant in the adhesive composition is not particularly limited, but is preferably 0 to 5 parts by mass, more preferably 0.01 to 2 parts by mass, further preferably 0.02 to 1 part by mass, particularly preferably 0.05 to 0.5 parts by mass, and most preferably 0.1 to 0.3 parts by mass, relative to 100 parts by mass of the block copolymer composition in the adhesive composition. By making the content of the benzofuranone antioxidant within the above range, the adhesive properties of the obtained adhesive can be further improved.

[0194] (3-5) Antioxidants

[0195] As the antioxidant, at least one selected from hindered phenol antioxidants, phosphorus antioxidants and sulfur antioxidants is preferred, and at least one selected from hindered phenol antioxidants and phosphorus antioxidants is more preferred. One antioxidant may be used alone or in combination of two or more. For example, one or more hindered phenol antioxidants may be used as the antioxidant, or a hindered phenol antioxidant and a phosphorus antioxidant may be used in combination as the antioxidant.

[0196] The content of the antioxidant in the adhesive composition (the total content of the antioxidants when two or more antioxidants are used) is not particularly limited, but is preferably 0.01 to 10 parts by mass, more preferably 0.05 to 5 parts by mass, further preferably 0.1 to 2 parts by mass, particularly preferably 0.15 to 1 part by mass, and most preferably 0.2 to 0.5 parts by mass, relative to 100 parts by mass of the block copolymer composition in the adhesive composition. By making the content of the antioxidant within the above range, the adhesive properties of the obtained adhesive can be further improved.

[0197] 4. Adhesive composition

[0198] The melt index of the adhesive composition of the present invention is a value measured according to ASTM D1238 (G condition, 200°C, 5kg load), preferably in the range of 1.5 to 50 g / 10 minutes, more preferably in the range of 2 to 40 g / 10 minutes, further preferably in the range of 3 to 30 g / 10 minutes, and particularly preferably in the range of 4 to 20 g / 10 minutes. By making the melt index of the adhesive composition within the above range, the processability of the adhesive composition can be further improved. The melt index of the adhesive composition can be adjusted by adjusting the molecular weight and monomer composition of each polymer constituting the block copolymer composition, the weight average molecular weight of the block copolymer composition as a whole, and the like.

[0199] 5. Method for producing adhesive composition

[0200] As a method for producing the adhesive composition of the present invention, a method having the following steps can be preferably cited: a solution preparation step of preparing a solution containing a block copolymer composition containing block copolymer A1 or block copolymer A2; an addition step of adding an alkyl radical scavenger to the solution of the block copolymer composition obtained in the solution preparation step to obtain a mixed solution; and a recovery step of removing the solvent from the mixed solution obtained in the addition step to recover a solid adhesive composition. Such a production method is described below.

[0201] (5-1) Solution Preparation Step

[0202] In the solution preparation process, the method for preparing a solution of a block copolymer composition containing block copolymer A1 or block copolymer A2 is not particularly limited. For example, a polymerization solution containing a block copolymer composition can be obtained by polymerizing the monomers used to form the block copolymer composition, and the polymerization solution can be used as a solution of the block copolymer composition for the later-described addition process. On the other hand, after obtaining a solid block copolymer composition by any method, the solid block copolymer composition is dissolved in a solvent to obtain a solution of the block copolymer composition, and the solution is used for the later-described addition process. As a method for preparing a solution of a block copolymer composition, the method for manufacturing a block copolymer composition containing block copolymer A1 or the method for manufacturing a block copolymer composition containing block copolymer A2 described later is preferred.

[0203] The block copolymer composition used in the present invention can be produced at once by the production method described below, or can be produced by preparing block copolymer A1 or block copolymer A2 and optionally mixing separately prepared diblock copolymer B, polymer C, and block copolymer D.

[0204] (5-1-1) Method for producing a block copolymer composition containing block copolymer A1

[0205] As a method for producing a block copolymer composition containing block copolymer A1, a method having the following steps can be preferably mentioned: a polymerization step of polymerizing an aromatic monovinyl monomer in a polymerization solvent using an organic lithium initiator to obtain an aromatic monovinyl polymer block chain; a polymerization step of polymerizing a conjugated diene monomer in a polymerization solvent using an organic lithium initiator in the presence of the above-mentioned aromatic monovinyl polymer block chain to obtain a diblock chain and a conjugated diene polymer block chain; and a coupling step of reacting a multifunctional coupling agent with the diblock chain and the conjugated diene polymer block chain.

[0206] (Polymerization process)

[0207] As the organic lithium initiator used in the polymerization process, it is possible to use a known organic lithium initiator that can initiate the polymerization of an aromatic monovinyl monomer and a conjugated diene monomer, and as a specific example thereof, organic monolithium initiators such as methyl lithium, n-propyl lithium, n-butyl lithium, and sec-butyl lithium can be cited. Among these, n-butyl lithium is preferred. The amount of the organic lithium initiator used is as long as it is the amount calculated by a method known to those skilled in the art according to the molecular weight of the desired polymer. In the present invention, by using an organic lithium initiator, the polymerization reaction is accompanied by activity, so there will be a polymer with an active terminal in the polymerization reaction system. Therefore, in the present invention, the polymer chain obtained in the polymerization process can be made to have an active terminal.

[0208] The polymerization solvent is not particularly limited as long as it is an inactive solvent to the organic lithium initiator. For example, an open-chain hydrocarbon solvent, a cyclic hydrocarbon solvent, or a mixed solvent thereof can be used. Examples of the open-chain hydrocarbon solvent include: n-butane, isobutane, n-hexane, or a mixture thereof; 1-butene, isobutene, trans-2-butene, cis-2-butene, or a mixture thereof; 1-pentene, trans-2-pentene, cis-2-pentene, or a mixture thereof; n-pentane, isopentane, neopentane, or a mixture thereof; and open-chain alkanes and alkenes having 4 to 6 carbon atoms such as 1-pentene, trans-2-pentene, cis-2-pentene, or a mixture thereof. In addition, examples of the cyclic hydrocarbon solvent include: aromatic hydrocarbons such as benzene, toluene, and xylene; and alicyclic hydrocarbons such as cyclohexane. From the perspective of controlling the polymerization temperature and controlling the molecular weight distribution, it is preferred to use a solvent that is a mixture of an open-chain hydrocarbon solvent and a cyclic hydrocarbon solvent. They are preferably used in a ratio of 5:95 to 50:50 in terms of the mass ratio of "open-chain hydrocarbon solvent: cyclic hydrocarbon solvent", and are further preferably used in a ratio of 10:90 to 40:60.

[0209] In addition, the above-mentioned polymerization reaction can also be carried out in the presence of a polar compound. By using a polar compound, the polymerization initiation rate and the molecular weight distribution can be adjusted. As polar compounds, aromatic ethers or aliphatic ethers or tertiary amines having a relative dielectric constant (25°C) of 2.5 to 5.0 can be cited. Specific examples of polar compounds include: aromatic ethers such as diphenyl ether and anisole; aliphatic ethers such as diethyl ether and dibutyl ether; tertiary monoamines such as trimethylamine, triethylamine, and tripropylamine; tertiary polyamines such as tetramethylethylenediamine and tetraethylethylenediamine. These polar compounds can be used alone or in combination of two or more. The amount of the polar compound used is preferably 0.001 to 50 moles relative to 1 mole of the organic lithium initiator, and more preferably 0.005 to 10 moles.

[0210] The polymerization method of the aromatic monovinyl monomer is not particularly limited, and any common method can be used, such as batch polymerization in which the entire amount of the aromatic monovinyl monomer and the entire amount of the initiator are added to the polymerization system at once for reaction, continuous polymerization in which they are continuously supplied to the polymerization system and reacted, and a method in which a part of the monomer and the initiator are polymerized to a predetermined conversion rate and then the remaining monomer and initiator are added to continue polymerization. The polymerization is usually carried out at 0°C to 90°C, preferably in the range of 20°C to 80°C. In the case where it is difficult to control the reaction temperature, it is preferred to use a reaction vessel equipped with a reflux condenser to control the temperature by reflux cooling.

[0211] Under the above conditions, an aromatic monovinyl monomer is polymerized in a solvent using an organic lithium initiator, thereby obtaining a solution containing an aromatic monovinyl polymer block chain. In addition, the aromatic monovinyl polymer block chain obtained by polymerization usually has an active end. In addition, since the obtained aromatic monovinyl polymer block chain forms an aromatic monovinyl polymer block (Ar 1 ) or aromatic monovinyl polymer block (Ar 3 ), so the amount of the monomer used in the polymerization step is determined according to the aromatic monovinyl polymer block (Ar 1 ) and aromatic monovinyl polymer blocks (Ar 3 ) can be determined by the weight average molecular weight.

[0212] Next, an organic lithium initiator and a conjugated diene monomer are added to the obtained solution containing the aromatic vinyl polymer block chain for polymerization. Thus, a solution containing diblock chains and conjugated diene polymer block chains can be obtained. In addition, the diblock chains and conjugated diene polymer block chains obtained by polymerization usually have active ends. In addition, the obtained diblock chains are formed in the formation of aromatic monovinyl polymer blocks (Ar 1 ) and aromatic monovinyl polymer blocks (Ar 3 ) is further bonded to the polymer chain to form a conjugated diene polymer block (D 1 ) or conjugated diene polymer block (D 3 ) polymer chain. Furthermore, the obtained conjugated diene polymer block chain forms a conjugated diene polymer block (D 2 ) and polymer C. Therefore, the amount of the monomers used in the polymerization step is determined according to the conjugated diene polymer block (D 1 ), conjugated diene polymer block (D 2 ), conjugated diene polymer block (D 3 ) and the weight average molecular weight of polymer C. In addition, the polymerization reaction temperature, polymerization time, and polymerization pressure are controlled within the same range as the polymerization of aromatic monovinyl monomers. In addition, during the polymerization of conjugated diene monomers, the above-mentioned polar compounds can also be used as randomizers to adjust the vinyl bond content in the conjugated diene monomer units.

[0213] (Coupling process)

[0214] Next, a multifunctional coupling agent is added to the solution containing the diblock chain and the conjugated diene polymer block chain. Thus, the active ends of the diblock chain and the conjugated diene polymer block chain react with the multifunctional coupling agent, and three or more side chains are bonded via the residue of the multifunctional coupling agent to form a block copolymer A1. As the multifunctional coupling agent, those mentioned above can be used. In addition, a compound having a coupling reaction promoting effect can also be added.

[0215] The amount of the multifunctional coupling agent can be adjusted to a suitable amount according to the number of branches of the block copolymer A1 and the content of the block copolymer A1 in the block copolymer composition. As the amount of the multifunctional coupling agent, relative to 1 mole of the organic lithium initiator, it is preferably in the range of 0.0001 to 20 moles, more preferably in the range of 0.01 to 10 moles, and further preferably in the range of 0.02 to 6 moles. By making the amount of the multifunctional coupling agent used in the above range, it is possible to suppress the side reaction from producing polymer components other than the block copolymer A1, and it is possible to easily obtain the block copolymer composition containing the block copolymer A1 as the target.

[0216] The suitable usage amount of multifunctional coupling agent can be calculated according to the number of branches of the block copolymer A1 as the target and the content of the block copolymer A1 in the block copolymer composition, but since the organic lithium initiator or the multifunctional coupling agent may be deactivated in the actual polymerization reaction, it is best to conduct preliminary experiments to find the optimum value. In addition, as required, reaction terminators such as methanol can be used to adjust the coupling rate. And then, the diblock chain and the conjugated diene polymer block chain obtained in the polymerization process can be left in an unreacted state by adjusting the usage amount of the multifunctional coupling agent, using a reaction terminator, etc., and finally recovered as diblock copolymer B and polymer C.

[0217] The reaction temperature is preferably 10 to 150° C., more preferably 30 to 130° C., and even more preferably 40 to 90° C. The time required for the reaction varies depending on the conditions, but is usually within 48 hours, preferably 0.5 to 10 hours.

[0218] By the above method, a solution of a block copolymer composition containing the block copolymer A1 can be prepared.

[0219] (5-1-2) Method for producing a block copolymer composition containing block copolymer A2

[0220] As a method for producing a block copolymer composition containing block copolymer A2, a method having the following steps can be preferably mentioned: a polymerization step of polymerizing an aromatic monovinyl monomer in a polymerization solvent using an organic lithium initiator to obtain a solution containing an aromatic monovinyl polymer block chain; a polymerization step of adding a conjugated diene monomer to the above-mentioned solution containing the aromatic monovinyl polymer block chain and polymerizing it to obtain a diblock chain; and a coupling step of reacting a multifunctional coupling agent with the diblock chain.

[0221] (Polymerization process)

[0222] The polymerization step of polymerizing an aromatic monovinyl monomer in a polymerization solvent using an organic lithium initiator to obtain a solution containing an aromatic monovinyl polymer block chain can be carried out in the same manner as the corresponding polymerization step in the method for producing a block copolymer composition containing block copolymer A1, and the preferred embodiment is also the same.

[0223] Specifically, an aromatic monovinyl monomer is polymerized in a solvent using an organic lithium initiator, thereby obtaining a solution containing an aromatic monovinyl polymer block chain. In addition, the aromatic monovinyl polymer block chain obtained by polymerization usually has an active end. In addition, since the obtained aromatic monovinyl polymer block chain forms an aromatic monovinyl polymer block (Ar) or an aromatic monovinyl polymer block (Ar 3 ), and therefore the amount of the monomers used in the polymerization step is determined according to the amount of the aromatic monovinyl polymer block (Ar) and the amount of the aromatic monovinyl polymer block (Ar 3 ) can be determined by the weight average molecular weight.

[0224] Next, a conjugated diene monomer is added to the obtained solution containing the aromatic vinyl polymer block chain for polymerization. Thus, a solution containing a diblock chain can be obtained. In addition, the diblock chain obtained by polymerization usually has an active end. In addition, the obtained diblock chain forms an aromatic monovinyl polymer block (Ar) and an aromatic monovinyl polymer block (Ar). 3 ) is further bonded to form a conjugated diene polymer block (D) or a conjugated diene polymer block (D 3 ) polymer chain. Therefore, the amount of the monomer used in the polymerization step is determined according to the conjugated diene polymer block (D) and the conjugated diene polymer block (D 3 ) can be determined. In addition, the polymerization reaction temperature, polymerization time, and polymerization pressure are controlled within the same range as the polymerization of aromatic monovinyl monomers. In addition, during the polymerization of conjugated diene monomers, the above-mentioned polar compounds can also be used as randomizers to adjust the vinyl bond content in the conjugated diene monomer units.

[0225] (Coupling process)

[0226] Next, a multifunctional coupling agent is added to the solution containing the diblock chain. Thus, the active end of the diblock chain reacts with the multifunctional coupling agent, and three or more side chains are bonded via the residue of the multifunctional coupling agent to form a block copolymer A2. As the multifunctional coupling agent, those mentioned above can be used. In addition, a compound having a coupling reaction promoting effect can also be added.

[0227] The usage amount of the multifunctional coupling agent can be adjusted to a suitable amount according to the number of branches of the block copolymer A2 and the content of the block copolymer A2 in the block copolymer composition. As the usage amount of the multifunctional coupling agent, relative to 1 mole of the organic lithium initiator, it is preferably in the range of 0.0001 to 20 moles, more preferably in the range of 0.01 to 10 moles, and further preferably in the range of 0.02 to 6 moles. By making the usage amount of the multifunctional coupling agent the above range, it is possible to suppress the side reaction from producing polymer components other than the block copolymer A2, and it is possible to easily obtain the block copolymer composition containing the block copolymer A2 as the target.

[0228] The suitable usage amount of multifunctional coupling agent can be calculated according to the number of branches of the block copolymer A2 as the target and the content of the block copolymer A2 in the block copolymer composition, but since the organic lithium initiator or the multifunctional coupling agent may be deactivated in the actual polymerization reaction, it is best to conduct preliminary experiments to find the optimum value. In addition, as required, reaction terminators such as methanol can be used to adjust the coupling rate. And then, the diblock chain obtained in the polymerization process can be left in an unreacted state by adjusting the usage amount of the multifunctional coupling agent, using a reaction terminator, etc., and finally recovered as a diblock copolymer B.

[0229] The conditions of the coupling step can be the same as those of the coupling step in the method for producing a block copolymer composition containing the block copolymer A1, and the preferred embodiment is also the same.

[0230] By the above method, a solution of a block copolymer composition containing the block copolymer A2 can be prepared.

[0231] (5-2) Adding process

[0232] In the adding step, an alkyl radical scavenger is added to the solution of the block copolymer composition containing block copolymer A1 or block copolymer A2 obtained as described above. Examples of the alkyl radical scavenger include those described above as the alkyl radical scavenger contained in the adhesive composition of the present invention.

[0233] In the adding step, in addition to adding the alkyl radical scavenger, a polymerization terminator and an antioxidant may be added as needed. Examples of the polymerization terminator include water, methanol, ethanol, propanol, hydrochloric acid, citric acid, etc. In addition, examples of the antioxidant include those described above as the antioxidant that the adhesive composition of the present invention may contain.

[0234] In the adding step, the alkyl radical scavenger and, if necessary, the polymerization terminator and antioxidant may be added by a conventional method, and the method is not particularly limited as long as the target adhesive composition can be recovered in the recovery step described later.

[0235] By the above method, a mixed solution containing the block copolymer composition, the alkyl radical scavenger, and, if necessary, the antioxidant can be obtained.

[0236] (5-3) Recovery process

[0237] In the recovery step, the solvent is removed from the mixed solution obtained as described above to recover the solid adhesive composition.

[0238] As a method for removing the solvent from a mixed solution, reclaiming a solid-state adhesive composition, there is no particular limitation, and the method of applying known methods such as direct drying method and steam stripping to a mixed solution can be cited. In addition, when steam stripping is applied to a solution, the polymer component is recovered as a slurry, and the granular adhesive composition can be reclaimed by dehydrating it using any dehydrator such as an extruder type squeezer. In addition, the granules can be dried using any drying machine such as a belt dryer or an expansion extrusion dryer. And then, the solid-state adhesive composition can be supplied for use after being processed into a particle shape according to a conventional method as required.

[0239] Since the adhesive composition of the present invention has excellent processability, the adhesive composition of the present invention can be well processed by applying strong shear stress (such as biaxial extrusion). The adhesive composition of the present invention can be obtained by applying strong shear stress (such as biaxial extrusion).

[0240] In addition, when a strong shear stress is applied to the block copolymer composition, alkyl radicals are generated as the molecular chains are cut due to the shear stress. The alkyl radicals react with the residues (X) of the multifunctional coupling agent in the block copolymer A1 or the block copolymer A2 contained in the block copolymer composition. 1 In the case of the reaction of (i) or (ii), the block copolymer A1 or the block copolymer A2 is crosslinked, thereby reducing the melt index. In addition, when a block copolymer composition with a significantly reduced melt index is used, the hot melt processability of the resulting adhesive will deteriorate.

[0241] In contrast, the adhesive composition of the present invention contains block copolymer A1 or block copolymer A2 and also contains an alkyl radical scavenger, so even when a strong shear stress is applied (such as a biaxial extrusion process), the crosslinking caused by the above reaction can be suppressed, so the melt index before and after the processing changes little. Therefore, such processing can be well implemented for the adhesive composition of the present invention. And then, even if the adhesive composition after such processing is used, an adhesive with excellent hot melt processability can be formed. The adhesive composition of the present invention can have such excellent processability, and can form an adhesive with excellent bonding properties.

[0242] In addition, the problem of crosslinking caused by the reaction of the alkyl radical with the residue of the multifunctional coupling agent is a problem unique to the case of using a coupling agent capable of forming a block copolymer having a total of three or more branches as the multifunctional coupling agent. On the other hand, when using a coupling agent such as dichlorodimethylsilane that cannot form a block copolymer having a total of three or more branches, the problem of crosslinking does not occur.

[0243] 6. Hot melt adhesive composition

[0244] The hot melt adhesive composition of the present invention contains the above-mentioned adhesive composition of the present invention, a tackifying resin, and a crosslinking agent. Since the hot melt adhesive composition of the present invention contains the above-mentioned adhesive composition of the present invention, it is excellent in hot melt processability and crosslinking property, and can form an adhesive having excellent adhesive properties (heat resistance stability, high temperature adhesiveness, and initial adhesiveness).

[0245] (6-1) Tackifying resin

[0246] As the tackifying resin, the existing known tackifying resin can be used. Specifically, as the tackifying resin, there can be mentioned: rosin; modified rosins such as disproportionated rosin and dimerized rosin; esters of polyols such as ethylene glycol, glycerol, pentaerythritol and rosin or modified rosins; terpene resins; hydrocarbon resins of aliphatic, aromatic, alicyclic or aliphatic-aromatic copolymers or their hydrogenates; phenolic resins; benzofuran-indene resins, etc. The tackifying resin preferably used is a hydrocarbon resin of an aliphatic or aliphatic-aromatic copolymer having good compatibility with the block copolymer composition used in the present invention. The tackifying resin can be used alone or in combination of two or more.

[0247] The content of the tackifier resin in the hot-melt adhesive composition is preferably in the range of 10 to 400 parts by mass, more preferably in the range of 30 to 300 parts by mass, and even more preferably in the range of 60 to 200 parts by mass, relative to 100 parts by mass of the block copolymer composition in the adhesive composition contained in the hot-melt adhesive composition.

[0248] (6-2) Cross-linking agent

[0249] As the crosslinking agent, a known crosslinking agent used in a hot melt adhesive composition can be used. Representative crosslinking systems include a peroxide crosslinking system, a sulfur crosslinking system, and a photocrosslinking system.

[0250] The peroxide crosslinking system includes a peroxide crosslinking agent. Examples of the peroxide crosslinking agent include tert-butyl hydroperoxide, cumene hydroperoxide, diisopropylbenzene peroxide, di-tert-butyl peroxide, tert-butyl isopropyl peroxide, 2,5-dimethyl-tert-butyl peroxyhexane, 2,5-dimethyl-tert-butyl peroxyhexyne, 1,3-bis(tert-butylperoxyisopropyl)benzene, p-chlorobenzoyl peroxide, tert-butyl peroxybenzoate, tert-butyl peroxyisopropyl carbonate, tert-butyl benzoate, and the like.

[0251] Furthermore, in the peroxide crosslinking system, in addition to these peroxide-based crosslinking agents, polyfunctional unsaturated compounds such as trimethylolpropane trimethacrylate, divinylbenzene, ethylene glycol dimethacrylate, polyethylene glycol polydimethacrylate, triallyl isocyanurate, triallyl cyanurate, diallyl phthalate, diallyl itaconate, and triallyl trimellitate can also be used as vulcanization aids.

[0252] The sulfur crosslinking system includes a sulfur-based crosslinking agent. Examples of the sulfur-based crosslinking agent include sulfur such as powdered sulfur, sulfur flowers, precipitated sulfur, colloidal sulfur, surface-treated sulfur, and insoluble sulfur; sulfur compounds such as sulfur chloride, sulfur dichloride, morpholine disulfide, alkylphenol disulfide, 1,1′-dithiobiscaprolactam (N,N′-Dithiobis(hexahydro-2H-azepinone-2)), phosphorus-containing polysulfide compounds, and polymer polysulfide compounds; and tetramethylthiuram disulfide, selenium dimethyldithiocarbamate, and 2-(4′-morpholinyldithio)benzothiazole. Furthermore, in addition to these sulfur-based crosslinking agents, the sulfur crosslinking system can also use: stearic acid; guanidine-based, aldehyde-amine-based, aldehyde-ammonia-based, thiazole-based, sulfenamide-based, thiourea-based, and xanthate-based vulcanization accelerators.

[0253] The photocrosslinking system can be any single compound or combination of compounds that can generate one or more free radicals that initiate monomer polymerization by sensing light such as ultraviolet light (UV) without causing excessive termination reactions. As known photocrosslinking systems, in particular, free radical photoinitiators such as quinone, benzophenone, benzoin ether, allyl ketone, peroxide, bisimidazole, benzyl dimethyl ketal, hydroxyalkylphenyl acetophenone, dialkoxyacetophenone, trimethylbenzoylphosphine oxide derivatives such as bis(2,4,6-trimethylbenzoyl)phenylphosphine oxide, aminoketone, benzoylcyclohexanol, methylthiophenylmorpholinone, morpholinophenylaminoketone, α-haloacetophenone, oxygen sulfonyl ketone, sulfonyl ketone, oxygen sulfonyl ketone, benzoyl oxime ester, 2-isopropylthioxanthone and the like, camphorquinone, ketocoumarin, and Michler's ketone can be used. Alternatively, the photocrosslinking system may be a mixture of compounds wherein one of the compounds provides free radicals when induced by a radiation-activated sensitizer. The photocrosslinking system is preferably a photocrosslinking system that senses visible light or ultraviolet light (chemical rays). In addition, the photocrosslinking system can use a free radical photoinitiator together with the above-mentioned multifunctional unsaturated compound.

[0254] The crosslinking agent used in the present invention is not limited to the above-mentioned crosslinking agents, and may be a crosslinking agent that can crosslink the hot melt adhesive composition in response to active energy rays such as electron beams and radiation.

[0255] The content of the crosslinking agent in the hot-melt adhesive composition is preferably in the range of 0.01 to 50 parts by mass, more preferably in the range of 0.1 to 20 parts by mass, and even more preferably in the range of 0.5 to 10 parts by mass, relative to 100 parts by mass of the block copolymer composition in the adhesive composition contained in the hot-melt adhesive composition.

[0256] (6-3) Plasticizer

[0257] The hot-melt adhesive composition of the present invention may contain a plasticizer in addition to the above-mentioned adhesive composition, tackifying resin, and cross-linking agent.

[0258] There are no particular limitations on the plasticizer (softener), but an organic compound that is liquid at room temperature (23°C) is preferably used. The type of plasticizer is not particularly limited as long as it is compatible with the block copolymer composition in the adhesive composition. Specifically, aromatic, paraffinic or cycloparaffinic process oils added to conventional hot-melt adhesive compositions; liquid polymers such as polybutene and polyisobutylene, etc. can be used, and among these, paraffinic process oils or cycloparaffinic process oils are particularly preferred. In addition, the plasticizer may be used alone or in combination of two or more.

[0259] The content of the plasticizer in the hot-melt adhesive composition is preferably within the range of 0 to 200 parts by mass, more preferably within the range of 1 to 100 parts by mass, and even more preferably within the range of 2 to 50 parts by mass, relative to 100 parts by mass of the block copolymer composition in the adhesive composition contained in the hot-melt adhesive composition. By setting the content of the plasticizer within the above range, it is possible to suppress bleeding while further improving hot-melt processability.

[0260] (6-4) Other ingredients

[0261] The hot melt adhesive composition of the present invention may also contain polymers other than the above-mentioned essential components. Examples of such polymers include conjugated diene homopolymers such as polybutadiene and polyisoprene, (styrene-butadiene) random copolymers, (styrene-isoprene) random copolymers and other aromatic vinyl-conjugated diene random copolymers, polystyrene and other aromatic vinyl homopolymers, isobutylene polymers, acrylic polymers, ester polymers, ether polymers, urethane polymers, polyvinyl chloride and other polymers having elasticity at room temperature (23°C), but are not limited thereto. In the hot melt adhesive composition of the present invention, the content of these polymers is preferably 20 parts by mass or less, more preferably 10 parts by mass or less relative to 100 parts by mass of the block copolymer composition in the adhesive composition contained in the hot melt adhesive composition.

[0262] In addition, an antioxidant can be added to the hot-melt adhesive composition of the present invention as needed. The type of antioxidant is not limited, and for example, those described above as antioxidants that can be contained in the adhesive composition of the present invention can be cited. An antioxidant can be used alone or in combination of two or more. In addition, when the hot-melt adhesive composition of the present invention is manufactured using an adhesive composition containing an antioxidant, an antioxidant of the same or different type as the antioxidant contained in the adhesive composition can be further added as needed.

[0263] The content of the antioxidant in the hot-melt adhesive composition (when using an adhesive composition containing an antioxidant, the total content of the antioxidant in the adhesive composition and the antioxidant added later) is not particularly limited, but is preferably in the range of 10 parts by mass or less, more preferably in the range of 0.5 to 5 parts by mass, relative to 100 parts by mass of the block copolymer composition in the adhesive composition contained in the hot-melt adhesive composition.

[0264] In addition, other compounding ingredients such as wax, heat stabilizer, ultraviolet absorber, filler, etc. can be further added to the hot melt adhesive composition of the present invention. In addition, the hot melt adhesive composition of the present invention is preferably a solvent-free composition containing no solvent.

[0265] (6-5) Hot Melt Adhesive Composition

[0266] When obtaining the hot melt adhesive composition of the present invention, the method of mixing the block copolymer composition, the tackifying resin, the crosslinking agent, and other components used as needed is not particularly limited, and examples thereof include: a method of dissolving each component in a solvent and mixing them uniformly, and then removing the solvent by heating or the like; and a method of melt mixing each component using a kneader or the like. From the viewpoint of more efficient mixing, melt mixing is preferred among these methods. In addition, the temperature during melt mixing is not particularly limited, and is generally in the range of 100 to 200°C.

[0267] The crosslinking property of the hot melt adhesive composition of the present invention is preferably set so that after the hot melt adhesive composition is crosslinked, 50% or more of the block copolymer composition is converted to a high molecular weight, more preferably 70% or more is converted to a high molecular weight, and further preferably 80% or more is converted to a high molecular weight. By having such crosslinking property, an adhesive having more excellent adhesive properties (heat resistance stability, adhesiveness at high temperature, and initial adhesiveness) can be formed.

[0268] To obtain appropriate crosslinking properties, the crosslinking properties may be appropriately adjusted by selecting the vinyl bond content in the conjugated diene monomer units in the block copolymer composition, the type and amount of the crosslinking agent and other ingredients, and the irradiation dose of active energy rays such as irradiated light.

[0269] When ultraviolet rays are used as active energy rays, ultraviolet light sources such as high-pressure mercury lamps, low-pressure mercury lamps, excimer lasers, and metal halide lamps can be used. The irradiation dose is usually 0.03 to 5 J / cm 2 In this case, a filter, PYREX (registered trademark) glass, or polyester sheet that shields short-wavelength ultraviolet rays may be used as needed. In addition, the temperature during ultraviolet irradiation is not particularly limited, and a heating condition from room temperature to 180° C. may be selected. Ultraviolet rays may be irradiated to a layer obtained by, for example, applying the hot-melt adhesive composition to a substrate.

[0270] 7. Adhesive

[0271] The adhesive of the present invention is formed from the hot-melt adhesive composition of the present invention described above, and can be obtained by crosslinking the block copolymer A1 or the block copolymer A2 in the hot-melt adhesive composition.

[0272] In the adhesive of the present invention, from the viewpoint of further improving the adhesive properties, preferably 50% or more of the block copolymer composition contained in the hot-melt adhesive composition is cross-linked, more preferably 70% or more of the block copolymer is cross-linked, and more preferably 80% or more of the block copolymer is cross-linked. In particular, the adhesive composition of the present invention has excellent hot-melt processability and can form an adhesive having excellent adhesive properties (heat-resistant stability, high-temperature adhesiveness, and initial adhesiveness), and also has excellent cross-linking properties. Therefore, even if the energy is small, the cross-linking ratio of the block copolymer contained in the hot-melt adhesive composition can be made high as described above, and an adhesive containing a large number of cross-linked sites can be obtained.

[0273] The purpose (object of bonding) of the hot-melt adhesive composition of the present invention and the adhesive is not particularly limited, and can be used for various bondings suitable for hot-melt bonding. It is particularly preferred to use as an adhesive for the so-called adhesive tape of the hot-melt adhesive composition melt-coated on a film-like substrate. For example, the hot-melt adhesive composition of the present invention can be melted by heating, melt-coated on the substrate, and before the hot-melt adhesive composition is completely cured, the adherend composed of the same or different materials as the material constituting the substrate is pressed to bond. In addition, at this time, the adhesive can also be made by cross-linking the hot-melt adhesive composition. The hot-melt adhesive composition of the present invention is good in hot-melt processability, so it helps to reduce the defective product rate and improve productivity in the manufacture of such an adhesive tape. And the adhesive properties (heat-resistant stability, adhesion at high temperature and initial adhesion) of the obtained adhesive tape are excellent. In addition, the hot-melt adhesive composition and adhesive of the present invention can be preferably used for: sanitary products such as disposable diapers and sanitary napkins; food packaging such as frozen foods, fresh foods, and snacks; parts packaging such as automobile parts and mechanical parts; electrical appliance packaging such as televisions, audio products, and refrigerators; binding purposes such as invoices, books, and product catalogs; bag making purposes such as kraft paper bags, polypropylene bags, and polyethylene bags; clothing purposes such as lapel of coats, lamination of leather and cloth, and bonding of linings, etc.

[0274] The hot melt adhesive composition and adhesive of the present invention are also used in the manufacture of labels. The label preferably has an adhesive layer and a support composed of the hot melt adhesive composition or adhesive of the present invention. The adhesive layer can usually be formed by applying the hot melt adhesive composition of the present invention on a support and drying it, and then cross-linking it as needed.

[0275] The support used is not particularly limited, and may be, for example, paper such as kraft paper, Japanese paper, high-quality paper, and synthetic paper; cloth such as cotton cloth, rayon cloth, and polyester cloth; resin films such as cellophane film, polyvinyl chloride film, polypropylene film, and polyethylene film; metal foils such as aluminum foil and copper foil; non-woven fabrics such as polyester non-woven fabric and rayon non-woven fabric, etc. These supports may be those whose surfaces have been subjected to corona discharge treatment or coated with a primer in advance.

[0276] The label obtained by using the hot-melt adhesive composition or adhesive of the present invention may be cut into a suitable shape according to its use, and may be subjected to punching or the like. Furthermore, the adhesive layer of the label using the hot-melt adhesive composition or adhesive of the present invention is not limited to a continuously formed adhesive layer. For example, the adhesive layer may be formed into a regular pattern such as dots or stripes, or a random pattern.

[0277] The present invention is not limited to the above-mentioned embodiments. The above-mentioned embodiments are merely examples, and any embodiments having substantially the same structure and having the same effects as the technical ideas described in the patent claims of the present invention are included in the technical scope of the present invention.

[0278] Example

[0279] The present invention will be described in more detail below with reference to Examples and Comparative Examples. In addition, unless otherwise specified, parts and % in each example are by mass.

[0280] Various measurements were performed according to the following methods.

[0281] [Weight average molecular weight and molecular weight distribution]

[0282] The molecular weight was determined as polystyrene equivalent by high performance liquid chromatography with tetrahydrofuran as carrier at a flow rate of 0.35 ml / min. The apparatus was HLC8320 manufactured by Tosoh Corporation, the chromatographic column was composed of three Shodex (registered trademark) KF-404HQ manufactured by Showa Denko K.K. connected together (column temperature 40°C), the detector used was a differential refractometer and an ultraviolet detector, and the molecular weight was calibrated at 12 points of standard polystyrene (5 to 3 million) manufactured by Polymer Laboratories Ltd.

[0283] [Content of Each Polymer in the Block Copolymer Composition]

[0284] It was determined from the area ratio of the peak corresponding to each polymer (block copolymer A1, block copolymer A2, diblock copolymer B, polymer C) in the chart obtained by the above high performance liquid chromatography.

[0285] [Weight average molecular weight of styrene polymer block of block copolymer]

[0286] According to the method described in Rubber Chem. Technol., 45, 1295 (1972), the block copolymer is reacted with ozone and reduced with lithium aluminum hydride, thereby decomposing the isoprene polymer block of the block copolymer. Specifically, proceed as follows. That is, in a reaction vessel equipped with 100 ml of dichloromethane treated with molecular sieves, 300 mg of the sample is dissolved. The reaction vessel is placed in a cooling tank so that it is -25 ° C, and then oxygen is passed into the reaction vessel at a flow rate of 170 ml / min while the ozone generated by the ozone generator is introduced. After 30 minutes from the start of the reaction, the gas flowing out of the reaction vessel is introduced into an aqueous solution of potassium iodide, thereby confirming that the reaction is complete. Then, 50 ml of diethyl ether and 470 mg of lithium aluminum hydride are loaded into another reaction vessel after nitrogen replacement, and the reaction vessel is cooled with ice water while the solution reacted with ozone is slowly added dropwise to the reaction vessel. Then, the reaction vessel is placed in a water bath, the temperature is gradually raised, and refluxed at 40°C for 30 minutes. After that, dilute hydrochloric acid is added dropwise to the reaction vessel while stirring the solution, and the addition is continued until almost no hydrogen is generated. After the reaction, the solid product produced in the solution is filtered out, and the solid product is extracted with 100 ml of diethyl ether for 10 minutes. The extract is combined with the filtrate when filtered out, and the solvent is distilled off to obtain a solid sample. For the sample obtained in this way, the weight average molecular weight is determined according to the above-mentioned weight average molecular weight determination method, and its value is used as the weight average molecular weight of the styrene polymer block.

[0287] [Weight average molecular weight of the isoprene polymer block of the block copolymer]

[0288] The weight average molecular weight of the isoprene polymer block was determined based on the calculated value by subtracting the weight average molecular weight of the corresponding styrene polymer block from the weight average molecular weight of the block copolymer determined as described above.

[0289] [Mass ratio of branches in block copolymer A1 (Ar 1 -D 1 ) / D 2 )]

[0290] 2 mL of the polymer solution before the coupling step was collected and mixed with 1 mL of excess methanol to inactivate the polymerization activity. The sample was analyzed by high performance liquid chromatography, and the mass ratio of the branched chains in the block copolymer A1 (Ar 1 -D 1 ) / D 2 ).

[0291] [Weight average molecular weight ratio (Mw(D1 )) / (Mw(D 2 )))]

[0292] In the same manner as above, the sample collected before the coupling step was analyzed by high performance liquid chromatography to determine Ar 1 -D 1 and D 2 The weight average molecular weight of the isoprene polymer block in the block copolymer A1 was calculated by subtracting the weight average molecular weight of the styrene polymer block of the block copolymer A1 obtained by the above method to obtain the weight average molecular weight ratio (Mw(D 1 )) / (Mw(D 2 ))).

[0293] [Average number of branches of block copolymer A1]

[0294] According to the weight average molecular weight and Ar of the block copolymer A1 obtained by the above method, 1 -D 1 and D 2 The weight average molecular weight of the block copolymer A1 and the mass ratio of the branched chains (Ar 1 -D 1 ) / D 2 ) to calculate the average number of branches of block copolymer A1.

[0295] [Average number of branches in block copolymer A2]

[0296] The same method as above was used to analyze the sample collected before the coupling step by high performance liquid chromatography to determine the weight average molecular weight of Ar-D. Then, the average number of branches of block copolymer A2 was calculated based on the weight average molecular weight of block copolymer A2 and the weight average molecular weight of Ar-D determined by the above method.

[0297] [Styrene unit content of the entire block copolymer composition]

[0298] Calculated based on proton NMR measurement.

[0299] [Type A Hardness of Block Copolymer Composition]

[0300] The type A hardness is measured using a durometer hardness tester (type A) in accordance with JIS K6253.

[0301] [Melt index of adhesive composition before and after biaxial extrusion]

[0302] The melt index of the pelletized adhesive composition before biaxial extrusion and the pelletized adhesive composition after biaxial extrusion was measured according to ASTM D1238 (G condition, 200°C, 5 kg load). The smaller the change in the melt index before and after biaxial extrusion, the better the processability of the adhesive composition can be judged.

[0303] [Hot melt processability]

[0304] 10 g of the hot melt adhesive composition was taken and the melt viscosity (unit: mPa・s) at 180°C was measured by a Thermosel type Brookfield viscometer using a No. 27 rotor. When the melt viscosity value was 500,000 mPa・s or less, the hot melt processability was excellent and the production of the adhesive using the hot melt was easy, so it was evaluated as "A", while on the other hand, when the melt viscosity value was greater than 500,000 mPa・s, the hot melt processability was poor, so it was evaluated as "B".

[0305] [Residual glue test]

[0306] The hot melt adhesive composition was melt-coated on a PET film with a thickness of 25 μm in a manner such that the thickness became 20 to 30 μm to obtain a coated sheet. Then, the coated sheet was cut to obtain a test piece before crosslinking. The test piece before crosslinking obtained in this way was crimped at a speed of 300 mm / min using a 2 kg rubber roller at 23°C, thereby pasting it to a stainless steel plate, and the test piece after 12 hours at 100°C after pasting was used as a measurement sample. For this measurement sample, according to PSTC-1 (180° peeling adhesion test specified by the American Pressure Sensitive Tape Committee), a high-speed peeling tester "TE-701-S" made by TESTER SANGYO CO,. LTD. was used as a measuring device, and peeling was performed at a peeling speed of 15 m / min at 23°C to obtain the peeling adhesion strength (N / m). In addition, the heat resistance stability of the hot melt adhesive composition before crosslinking was evaluated by visually confirming whether there was residual adhesive on the stainless steel plate after peeling.

[0307] In addition, the test pieces before crosslinking were exposed to UV-C light at 100 mJ / cm 2 The hot melt adhesive composition is cross-linked by irradiating ultraviolet rays under the conditions of , and a test piece having an adhesive layer is obtained. The obtained test piece is used to obtain the peeling strength (N / m) of the cross-linked adhesive and evaluate the heat resistance stability. Specifically, the test piece where no residual adhesive can be seen is evaluated as "A", the test piece where a part of the residual adhesive can be seen is evaluated as "B", and the test piece where the residual adhesive can be seen as a whole is evaluated as "C". The less the residual adhesive is, the better the heat resistance stability can be judged.

[0308] [SAFT]

[0309] The hot melt adhesive composition was melt-coated on a PET film having a thickness of 25 μm in a manner such that the thickness was 20 to 30 μm to obtain a coated sheet. Next, the coated sheet was cut to obtain a test piece before crosslinking. Using the test piece before crosslinking obtained in this way, it was contacted with stainless steel as an adherend in a manner such that the adhesive portion became 10×25 mm, and a 2 kg rubber roller was used to press at a speed of 300 mm / min under the condition of 23°C to obtain a measurement sample. A load of 500 g of a weight was applied to the measurement sample, and the shear failure temperature (SAFT) of the hot melt adhesive composition before crosslinking was measured at a heating rate of 0.5°C / min.

[0310] In addition, the test pieces before crosslinking were exposed to UV-C light at 100 mJ / cm 2 The hot melt adhesive composition is cross-linked by irradiating ultraviolet rays under the conditions of , and a test piece having an adhesive layer is obtained. The obtained test piece is used to measure the shear failure temperature (SAFT) of the cross-linked adhesive. The higher the shear failure temperature (SAFT), the better the adhesive performance at high temperature (adhesion at high temperature) can be judged.

[0311] [Ring initial viscosity]

[0312] The hot melt adhesive composition was melt-coated on a 25 μm PET film in a manner to make the thickness of 20 to 30 μm to obtain a coated sheet. Next, the coated sheet was cut to obtain a test piece before cross-linking. Using the test piece before cross-linking obtained in this way, a stainless steel plate was used as the adherend, and the ring initial adhesion (N / 25mm) of the hot melt adhesive composition before cross-linking was evaluated by a tensile tester under the conditions of a test speed of 300 mm / min, a bonding portion of 25×25 mm, and a temperature of 23°C.

[0313] In addition, the test pieces before crosslinking were exposed to UV-C light at 100 mJ / cm 2 The hot melt adhesive composition was cross-linked by irradiating ultraviolet rays under the conditions of , to obtain a test piece having an adhesive layer. The obtained test piece was used to evaluate the initial adhesion of the adhesive after cross-linking. The larger the value, the better the initial adhesion.

[0314] [Crosslinking]

[0315] For hot melt adhesive compositions, UV-C light was used at 100 mJ / cm 2The conditions of irradiation light are used to crosslink the adhesive. Then, the hot melt adhesive composition before crosslinking and the adhesive after crosslinking are measured by high performance liquid chromatography to evaluate the crosslinking property. Specifically, in the case where the block copolymer A1 or block copolymer A2 before crosslinking is crosslinked and high molecular weighted, the peak area of ​​the block copolymer A1 or block copolymer A2 is reduced, and the peak area of ​​the block copolymer A1 or block copolymer A2 contained in the hot melt adhesive composition before crosslinking is used as a reference to obtain the reduction ratio of the peak area of ​​the block copolymer A1 or block copolymer A2 before and after crosslinking. In addition, in the table, ">90 (%)" means that the reduction ratio of the peak area is greater than 90%. The greater the reduction ratio of the peak area, the more excellent the crosslinking property can be judged.

[0316] [Production Example 1]

[0317] A 2-liter pressure-resistant reactor was used, and 400 g of a mixed solvent of n-butane / cyclohexane = 30 / 70, 0.07 mmol of tetramethylethylenediamine, 2.25 mmol of initiator n-butyllithium were loaded, 22 g of styrene was added, and polymerization was carried out at 30 ° C for 1 hour, followed by adding 78 g of isoprene, while the reaction temperature was controlled between 50 ° C and 60 ° C by reflux cooling, and polymerization was carried out for about 1 and a half hours. Next, divinylbenzene (DVB) with a 4-fold equivalent relative to all n-butyllithium was added as a coupling agent, and a coupling reaction was carried out for 2 hours. Afterwards, 1 ml of methanol was added to the reaction mixture as a polymerization terminator to obtain a solution containing a block copolymer composition (1). Using the obtained solution, the block copolymer composition (1) in the solution was measured as described above. The results are shown in Table 1.

[0318] [Production Example 2]

[0319] A 2-liter pressure-resistant reactor was used, and 400 g of a mixed solvent of n-butane / cyclohexane in a ratio of 30 / 70, 0.07 mmol of tetramethylethylenediamine, 1.75 mmol of initiator n-butyllithium were charged, and 22 g of styrene were added, and polymerization was carried out at 30°C for 1 hour. Then, 0.75 mmol of n-butyllithium and 78 g of isoprene were added, and the polymerization was carried out for about 1 and a half hours while the reaction temperature was controlled between 50°C and 60°C by reflux cooling. Next, divinylbenzene (DVB) in an amount of 4 times the equivalent of all n-butyllithium was added as a coupling agent, and a coupling reaction was carried out for 2 hours. Afterwards, 1 ml of methanol was added to the reaction mixture as a polymerization terminator to obtain a solution containing a block copolymer composition (2). Using the obtained solution, the block copolymer composition (2) in the solution was measured as described above. The results are shown in Table 1.

[0320] [Production Example 3]

[0321] A 2-liter pressure-resistant reactor was used, and 400 g of a mixed solvent of n-butane / cyclohexane = 30 / 70, 0.07 mmol of tetramethylethylenediamine, and 2 mmol of initiator n-butyllithium were loaded, 25 g of styrene was added, and polymerization was carried out at 30 ° C for 1 hour, followed by adding 75 g of isoprene, while the reaction temperature was controlled between 50 ° C and 60 ° C by reflux cooling, and polymerization was carried out for about 1 and a half hours. Next, 0.375 times the equivalent of dichlorodimethylsilane (DMDCS) relative to the total n-butyllithium was added as a coupling agent for 2 hours of coupling reaction. Afterwards, 1 ml of methanol was added to the reaction mixture as a polymerization terminator to obtain a solution containing a block copolymer composition (3). Using the obtained solution, the block copolymer composition (3) in the solution was measured as described above. The results are shown in Table 1.

[0322] [Table 1]

[0323]

[0324] In the Examples and Comparative Examples, the following alkyl radical scavengers and antioxidants were used.

[0325] [Hindered phenol antioxidants]

[0326] ・IRGANOX 1010: Pentaerythritol tetrakis[3-[3,5-di-tert-butyl-4-hydroxyphenyl]propionate], manufactured by BASF

[0327] ・IRGANOX 565: 4-[[4,6-bis(octylthio)-1,3,5-triazin-2-yl]amino]-2,6-di-tert-butylphenol, manufactured by BASF

[0328] [Phosphorus antioxidants]

[0329] ・IRGAFOS 168: Tris(2,4-di-tert-butylphenyl) phosphite, manufactured by BASF

[0330] [Alkyl radical scavenger]

[0331] ・SUMILIZER GM: 2-tert-butyl-6-(3-tert-butyl-2-hydroxy-5-methylbenzyl)-4-methylphenyl acrylate, manufactured by Sumitomo Chemical Co., Ltd.

[0332] ・SUMILIZER GS: 2-[1-(2-hydroxy-3,5-di-tert-pentylphenyl)ethyl]-4,6-di-tert-pentylphenyl acrylate, manufactured by Sumitomo Chemical Co., Ltd.

[0333] [Example 1-1]

[0334] To the solution containing the block copolymer composition (1) obtained in Preparation Example 1, 0.1 parts of IRGANOX 1010, 0.2 parts of IRGAFOS 168, and 0.2 parts of SUMILIZER GM were added relative to 100 parts of the block copolymer composition (1), and the mixture was thoroughly mixed. The obtained mixed solution was added dropwise little by little to hot water heated to 85 to 95° C. to volatilize the solvent and recover the granular adhesive composition. The obtained granular adhesive composition was put into a twin-screw kneading extruder for twin-screw extrusion processing to obtain a granular adhesive composition. The structure of the twin-screw kneading extruder used and the twin-screw extrusion processing conditions are shown below.

[0335] [Structure of the twin-screw kneading extruder]

[0336] Co-rotating twin-shaft kneading extruder HK-25D (41D) (manufactured by Parker Corporation)

[0337] φ25mm, L / D=41, number of barrels=7

[0338] [Twin-screw compounding extrusion conditions]

[0339] Barrel setting temperature: 180℃

[0340] Resin temperature: 210℃

[0341] Speed ​​(rpm): 100

[0342] Feeding speed (using weight feeder): 5kg / h

[0343] The melt index was measured as described above using the pelletized adhesive composition before biaxial extrusion and the pelletized adhesive composition after biaxial extrusion.

[0344] [[Example 1-2 to Example 1-6, Comparative Examples 1-1 to 1-6]

[0345] As shown in Table 2, the solution obtained in any one of Manufacturing Examples 1 to 3 was used as the solution containing the block copolymer composition, and IRGANOX 1010, IRGANOX 565, IRGAFOS 168, SUMILIZER GM and SUMILIZER GS were used in the amounts shown in Table 2 relative to 100 parts of the block copolymer composition. The same method as in Example 1-1 was used to obtain a pelletized adhesive composition and a granular adhesive composition. The obtained adhesive composition was measured in the same manner as in Example 1-1. The results are shown in Table 2.

[0346] [Table 2]

[0347]

[0348] [Example 2-1]

[0349] The granular adhesive composition obtained in Example 1-1 was charged into a stirring blade type kneader, and 100 parts of a petroleum resin (aliphatic-aromatic copolymer hydrocarbon resin, trade name "QUINTON S195", manufactured by Japan Zeon Co., Ltd.), 10 parts of a cycloparaffinic process oil (trade name "SUNPURE N100", manufactured by Japan Sun Oil Co., Ltd.) as a softener (plasticizer), 1 part of a crosslinking agent 1 (bis(2,4,6-trimethylbenzoyl)phenylphosphine oxide, Omnirad 819, manufactured by IGM RESINS), 1 part of a crosslinking agent 2 (2-isopropylthioxanthone, 2-ITX, manufactured by IGM RESINS) and 1 part of IRGANOX 1010 were added thereto, and after replacing the system with nitrogen, the mixture was kneaded at 160° C. for 1.5 hours to prepare a hot melt adhesive composition.

[0350] The obtained hot-melt adhesive composition was used to evaluate hot-melt processability, residual adhesive test, SAFT, loop tack, and crosslinking properties.

[0351] [[Example 2-2 to Example 2-6, Comparative Examples 2-1 to 2-6]

[0352] A hot melt adhesive composition was obtained in the same manner as in Example 2-1 except that the adhesive composition obtained in the examples or comparative examples shown in Table 3 was used instead of the adhesive composition obtained in Example 1-1. The obtained hot melt adhesive composition was measured in the same manner as in Example 2-1. The results are shown in Table 3.

[0353] [Table 3]

[0354]

[0355] As shown in Table 3, an adhesive composition containing a block copolymer A1 represented by the general formula (1) or a block copolymer A2 represented by the general formula (2), and an alkyl radical scavenger, wherein the weight average molecular weight (Mw) of the block copolymer composition as a whole is 300,000 to 800,000, and the content of the alkyl radical scavenger is 0.05 to 2 parts by mass relative to 100 parts by mass of the block copolymer composition has excellent processability and can form an adhesive having excellent adhesive properties (Examples 1-1 to 1-6 and Examples 2-1 to 2-6).

[0356] On the other hand, in the case of a block copolymer composition containing block copolymer A1 or block copolymer A2 but not containing an alkyl radical scavenger, the result was that the melt index before biaxial extrusion processing changed greatly, and the hot melt processability of the obtained hot melt adhesive composition was poor, and the processability was poor (Comparative Examples 1-1, 1-2, 1-4 and Comparative Examples 2-1, 2-2, 2-4).

[0357] Furthermore, when the content of the alkyl radical scavenger was too high, the adhesive properties of the obtained adhesive were poor as a result (Comparative Examples 1-3 and 2-3).

[0358] In addition, in the case of a block copolymer composition not containing block copolymer A1 or block copolymer A2, the melt index before biaxial extrusion processing hardly changed regardless of the presence or absence of an alkyl radical scavenger, but the adhesive properties of the obtained adhesive were poor (Comparative Examples 1-5, 1-6 and Comparative Examples 2-5, 2-6).

Claims

1. An adhesive composition comprising a block copolymer composition and an alkyl radical scavenger, wherein the block copolymer composition comprises a block copolymer A1 represented by the following general formula (1) or a block copolymer A2 represented by the following general formula (2), The weight average molecular weight (Mw) of the block copolymer composition as a whole is 300,000 to 800,000, The content of the alkyl radical scavenger is 0.05 to 2 parts by mass relative to 100 parts by mass of the block copolymer composition. In the general formula (1), Ar 1 is an aromatic monovinyl polymer block, D 1 and D 2 are conjugated diene polymer blocks, m is an integer greater than 1, n is an integer greater than 1, m+n is an integer greater than 3, and X 1 is the residue of a multifunctional coupling agent, In the general formula (2), Ar is an aromatic monovinyl polymer block, D is a conjugated diene polymer block, p is an integer of 3 or more, and X is a residue of a polyfunctional coupling agent.

2. The adhesive composition according to claim 1, wherein The molecular weight distribution (Mw / Mn) of the block copolymer A1 or the block copolymer A2 is 1.40 or less, The total content of the block copolymer A1 and the block copolymer A2 in the block copolymer composition is 10% by mass or more.

3. The adhesive composition according to claim 1 or 2, wherein The block copolymer composition further comprises a diblock copolymer B represented by the following general formula (3) or a polymer C represented by the following general formula (4), The molecular weight distribution (Mw / Mn) of the diblock copolymer B or the polymer C is 1.20 or less, The total content of the diblock copolymer B and the polymer C in the block copolymer composition is 60% by mass or less, The content of the aromatic monovinyl monomer unit in the block copolymer composition is 5 to 40% by mass. The block copolymer composition has a type A hardness of 25 to 65 as measured using a durometer hardness tester (type A) in accordance with JIS K6253. In the general formula (3) and the general formula (4), Ar 3 is an aromatic monovinyl polymer block, D 3 and D 4 They are conjugated diene polymer blocks, respectively.

4. The adhesive composition according to any one of claims 1 to 3, wherein The melt index measured in accordance with ASTM D1238 (G condition, 200° C., 5 kg load) is 1.5 to 50 g / 10 minutes.

5. The adhesive composition according to any one of claims 1 to 4, wherein The block copolymer composition comprises the block copolymer A1, In the block copolymer A1, Ar 1 -D 1 The mass of the branched chain is expressed relative to that of D 2 The ratio of the mass of the branched chain (Ar 1 -D 1 ) / D 2 ) is 1.0 / 0.15~1.0 / 1.

75.

6. The adhesive composition according to any one of claims 1 to 5, wherein The block copolymer composition contains the block copolymer A1, In the block copolymer A1, Ar 1 -D 1 The conjugated diene polymer block D in the branched chain 1 The weight average molecular weight (Mw(D 1 )) Relative to D 2 The weight average molecular weight (Mw(D 2 )) ratio ((Mw(D 1 )) / (Mw(D 2 ))) is 1.0 / 0.3~1.0 / 1.

1.

7. The adhesive composition according to any one of claims 1 to 6, wherein The multifunctional coupling agent is a compound having two or more free radical polymerizable groups in a molecule.

8. The adhesive composition according to claim 7, wherein The multifunctional coupling agent is divinylbenzene.

9. The adhesive composition according to any one of claims 1 to 8, wherein The conjugated diene polymer block is an isoprene polymer block.

10. The adhesive composition according to any one of claims 1 to 9, wherein The alkyl radical scavenger is at least one selected from 2-[1-(2-hydroxy-3,5-di-tert-pentylphenyl)ethyl]-4,6-di-tert-pentylphenyl acrylate and 2-tert-butyl-6-(3-tert-butyl-2-hydroxy-5-methylbenzyl)-4-methylphenyl acrylate.

11. The adhesive composition according to any one of claims 1 to 10, wherein The adhesive composition further contains at least one antioxidant selected from the group consisting of hindered phenol antioxidants, phosphorus antioxidants, sulfur antioxidants, and benzofuranone antioxidants. The content of the antioxidant is 0.01 to 10 parts by mass based on 100 parts by mass of the block copolymer composition.

12. A hot-melt adhesive composition comprising the adhesive composition according to any one of claims 1 to 11, a tackifying resin and a cross-linking agent, The content of the tackifier resin is 10 to 400 parts by mass, and the content of the crosslinking agent is 0.01 to 50 parts by mass, relative to 100 parts by mass of the block copolymer composition in the adhesive composition. 13 . The hot-melt adhesive composition according to claim 12 , comprising 0 to 200 parts by mass of a plasticizer based on 100 parts by mass of the block copolymer composition in the adhesive composition.

14. An adhesive formed from the hot-melt adhesive composition according to claim 12 or 13, The adhesive is obtained by crosslinking the block copolymer A1 or the block copolymer A2 in the hot-melt adhesive composition.

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