Pressure-sensitive adhesive composition, pressure-sensitive adhesive sheet, and

Abstract

To improve the adhesive force of an adhesive composition.SOLUTION: (A) and nanocellulose, wherein the block polymer (A) includes a polymer block (A1) and a (meth) acrylic polymer block (A2).SELECTED DRAWING: None

Description

[Technical Field]

[0001] The present invention relates to a pressure-sensitive adhesive composition, a pressure-sensitive adhesive sheet, and a textile product. [Background technology]

[0002] Pressure-sensitive adhesives are sometimes used, for example, to bond flexible adherends together (for example, fiber fabrics, a fiber fabric and a flexible conductive sheet, or a fiber fabric and an elastomer material).

[0003] In recent years, a seamless construction method in which fiber fabrics are bonded together with an adhesive instead of being sewn together has been attracting attention in the field of clothing, etc. Advantages of seamless construction include improved design, reduced skin irritation caused by underwear, and improved wind resistance and heat retention of winter clothing.

[0004] Patent Document 1 aims to "provide a pressure-sensitive adhesive composition that can strongly bond fiber layers together without impairing the texture of the fiber layers after bonding," and discloses "a pressure-sensitive adhesive composition containing a block copolymer having a polymer block (A) and a (meth)acrylic polymer block (B), wherein the polymer block (A) is a polymer having a glass transition temperature (Tg) of 50°C or more and 350°C or less, and the (meth)acrylic polymer block (B) is a polymer containing 50% by mass or more and 99% by mass or less of structural units derived from a (meth)acrylic acid alkoxyalkyl ester and having a glass transition point of -50°C or more and -10°C or less, and wherein the pressure-sensitive adhesive composition has a storage modulus at 23°C of 0.01 MPa or more and 0.50 MPa or less."

[0005] Furthermore, pressure-sensitive adhesive compositions for bonding fiber fabrics are also disclosed in, for example, Patent Documents 2 to 4. [Prior art documents] [Patent documents]

[0006] [Patent Document 1] Japanese Patent Application Publication No. 2020-59829 [Patent Document 2] Japanese Patent Application Publication No. 2019-11382 [Patent Document 3] International Publication No. 2020 / 059637 [Patent Document 4] Patent Publication No. 2021-75585 Summary of the Invention [Problem to be solved by the invention]

[0007] An object of the present invention is to improve the adhesive strength of a pressure-sensitive adhesive composition. [Means for solving the problem]

[0008] Adhesion can be improved by combining nanocellulose with a polymer having a specific structure.

[0009] The present invention includes the following embodiments. [1] a block copolymer (A); Nanocellulose and Including, The block copolymer (A) is a polymer block (A1), a (meth)acrylic polymer block (A2); Including, Pressure-sensitive adhesive composition. [2] The pressure-sensitive adhesive composition according to [1], wherein the glass transition temperature of the polymer block (A1) is 10°C or higher and 220°C or lower. [3] The pressure-sensitive adhesive composition according to [1] or [2], wherein the (meth)acrylic polymer block (A2) has a glass transition temperature of -80°C or higher and lower than 10°C. [4] The polymer block (A1) a structural unit (A1U1) derived from an imide group-containing vinyl monomer; A structural unit (A1U2) derived from a (meth)acrylic monomer (excluding an imide group-containing vinyl monomer), The pressure-sensitive adhesive composition according to any one of [1] to [3], comprising: [5] The pressure-sensitive adhesive composition according to [4], wherein the total amount of the structural unit (A1U1) and the structural unit (A1U2) is 60 mass % or more based on the mass of all structural units of the polymer block (A1). [6] The structural unit (A1U2) is represented by the following formula (1): CH2=CR 1 -C(=O)O(R 2 O) n -R 3 (1) [R 1 is a hydrogen atom or a methyl group, R 2 is a linear or branched alkylene group having 2 to 6 carbon atoms, R 3 is a hydrogen atom or an alkyl group having 1 to 20 carbon atoms, n is an integer from 0 to 100. The pressure-sensitive adhesive composition according to [4] or [5], which contains a structural unit derived from a compound represented by the following formula: [7] The pressure-sensitive adhesive composition according to any one of [1] to [6], wherein the pressure-sensitive adhesive layer formed from the pressure-sensitive adhesive composition has a storage modulus at 23° C. of 1.0 MPa or less. [8] The pressure-sensitive adhesive composition according to any one of [1] to [7], wherein the (meth)acrylic polymer block (A2) contains a structural unit (A2U1) derived from a (meth)acrylic acid ester. [9] The pressure-sensitive adhesive composition according to [8], wherein the amount of the structural unit (A2U1) is 15 mass % or more based on the mass of all structural units of the (meth)acrylic polymer block (A2).

[10] The block copolymer (A) is a triblock copolymer as follows: [Said block (A1)] - [Said block (A2)] - [Said block (A1)] The pressure-sensitive adhesive composition according to any one of [1] to [9], comprising:

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

[10] , further comprising a silane coupling agent.

[12] The pressure-sensitive adhesive composition according to any one of [1] to

[11] , wherein the nanocellulose has a modifying group.

[13] The pressure-sensitive adhesive composition according to

[12] , wherein the modifying group is introduced to at least some of the hydroxyl groups of the nanocellulose via a covalent bond.

[14] The hydroxyl group to which the modifying group has been introduced is represented by the following formula (2): RC(=O)-O- (2) wherein R is a substituted or unsubstituted alkyl group, a substituted or unsubstituted cycloalkyl group, a substituted or unsubstituted alkenyl group, or a substituted or unsubstituted cycloalkenyl group. The pressure-sensitive adhesive composition according to

[13] ,

[15] The pressure-sensitive adhesive composition according to

[12] , wherein the modifying group is introduced to at least some of the carboxy groups of the nanocellulose via an ionic bond.

[16] The pressure-sensitive adhesive composition according to

[15] , wherein the modifying group has an amino group.

[17] The pressure-sensitive adhesive composition according to any one of [1] to

[16] , wherein the nanocellulose contains an oxide of a cellulose-based raw material with hypochlorous acid or a salt thereof, and is substantially free of N-oxyl compounds.

[18] The pressure-sensitive adhesive composition according to any one of [1] to

[17] , wherein the nanocellulose has a structure in which the hydroxyl groups at the second and third positions of the glucopyranose ring are oxidized to introduce dicarboxy groups.

[19] The pressure-sensitive adhesive composition according to any one of [1] to

[18] , which does not contain a crosslinking agent.

[20] A pressure-sensitive adhesive sheet comprising the pressure-sensitive adhesive composition according to any one of [1] to

[19] . [twenty one] A textile product adhered with the pressure-sensitive adhesive composition according to any one of [1] to

[19] . [Effects of the Invention]

[0010] The present invention can improve the adhesive strength of a pressure-sensitive adhesive composition. DETAILED DESCRIPTION OF THE INVENTION

[0011] Hereinafter, embodiments of the present invention will be described in detail, but the present invention is not limited to these and various modifications are possible without departing from the gist of the present invention.

[0012] As used herein, "(meth)acrylate" refers to acrylate and methacrylate. As used herein, "(meth)acryloyl" means acryloyl and methacryloyl. In this specification, "(meth)acrylic" means acrylic and methacrylic.

[0013] <<Adhesive composition>> One embodiment of the present invention relates to a pressure-sensitive adhesive composition comprising a block copolymer (A) and nanocellulose, wherein the block copolymer (A) comprises a polymer block (A1) and a (meth)acrylic polymer block (A2).

[0014] In the pressure-sensitive adhesive composition according to this embodiment, the use of a polymer having a predetermined structure in combination with nanocellulose can improve adhesive strength (peel strength). In addition, the pressure-sensitive adhesive composition according to this embodiment can also improve storage modulus.

[0015] The storage modulus at 23°C of the pressure-sensitive adhesive layer formed from the pressure-sensitive adhesive composition according to this embodiment is preferably 1.0 MPa or less, more preferably 750 kPa or less, and even more preferably 500 kPa or less. The lower limit of the storage modulus is not particularly limited, and may be, for example, 30 kPa, 40 kPa, or 50 kPa. The range of the storage modulus (0°C) can be determined by appropriately combining the above-mentioned upper and lower limits. The range of the storage modulus (0°C) may be, for example, 30 to 500 kPa, 50 to 1000 kPa, or 30 to 1000 kPa.

[0016] The method for preparing the pressure-sensitive adhesive layer and the method for measuring the storage modulus are as described in the Examples below.

[0017] The storage modulus can be adjusted, for example, by changing the amount of modified nanocellulose. For example, increasing the amount of modified nanocellulose tends to increase the storage modulus.

[0018] <Block copolymer (A)> The pressure-sensitive adhesive composition according to this embodiment contains a block copolymer (A). The block copolymer (A) preferably contains a plurality of polymer blocks having different monomer compositions.

[0019] The glass transition temperature of the block copolymer (A) is preferably -80°C or higher and lower than 10°C, more preferably -70°C or higher and 0°C or lower, even more preferably -60°C or higher and -10°C or lower, and particularly preferably -50°C or higher and -20°C or lower.

[0020] By adjusting the glass transition temperature of the block copolymer (A) to fall within the above range, the adhesive strength tends to be further improved.

[0021] The glass transition temperature of the block copolymer (A) can be adjusted by changing the type and amount of the monomers that constitute the polymer.

[0022] The method for measuring the glass transition temperature of the block copolymer (A) is as described in the Examples below.

[0023] The number average molecular weight (Mn) of the block copolymer (A) is preferably 30,000 or more and 400,000 or less, more preferably 50,000 or more and 300,000 or less, and even more preferably 70,000 or more and 200,000 or less.

[0024] The weight average molecular weight (Mw) of the block copolymer (A) is preferably 100,000 or more and 700,000 or less, more preferably 130,000 or more and 600,000 or less, and even more preferably 150,000 or more and 500,000 or less.

[0025] The molecular weight distribution (Mw / Mn) of the block copolymer (A) is preferably 1.0 or more and 6.0 or less, more preferably 1.1 or more and 5.0 or less, and even more preferably 1.2 or more and 4.0 or less.

[0026] By setting the Mn, Mw, and / or Mw / Mn of the block copolymer (A) within the above ranges, the adhesive strength tends to be further improved.

[0027] The Mn and Mw of the block copolymer (A) can be measured by converting the molecular weight measured by gel permeation chromatography (GPC) into polystyrene equivalents.

[0028] The amount of the block copolymer (A) is preferably 50 to 99 mass %, more preferably 70 to 97 mass %, and even more preferably 90 to 95 mass %, based on the mass of the solid content of the pressure-sensitive adhesive composition (i.e., components excluding the solvent).

[0029] The block copolymer (A) contains a polymer block (A1) and a (meth)acrylic polymer block (A2). When the block copolymer (A) contains the polymer block (A1) and the (meth)acrylic polymer block (A2), the polymer block (A1) and the (meth)acrylic polymer block (A2) are not the same. It is preferable that the block (A1) has a higher glass transition temperature than the block (A2).

[0030] The ratio (A1 / A2) of the block (A1) to the block (A2) is preferably 1 / 99 to 70 / 30, more preferably 3 / 97 to 60 / 40, and even more preferably 5 / 95 to 50 / 50.

[0031] The total amount of the block (A1) and the block (A2) is preferably 80% by mass or more, more preferably 90% by mass or more, and even more preferably 95% by mass or more, based on the mass of the block copolymer (A).

[0032] The structure of the block copolymer (A) is, for example, [Block (A1)]-[Block (A2)] [Block (A1)]-[Block (A2)]-[Block (A1)] [Block (A2)]-[Block (A1)]-[Block (A2)] Examples include:

[0033] The block copolymer (A) preferably has the following triblock structure: [Block (A1)]-[Block (A2)]-[Block (A1)] By having such a triblock structure, the block (A1) functions as a pseudo crosslinking point between the block copolymers (A), which tends to further improve adhesive strength.

[0034] [Polymer block (A1)] The block copolymer (A) contains a polymer block (A1), which can function as a pseudo-crosslinking point between the block copolymers (A).

[0035] The glass transition temperature of the block (A1) is preferably from 10° C. to 280° C., more preferably from 20° C. to 250° C., and even more preferably from 40° C. to 220° C. The glass transition temperature of the block (A1) refers to the glass transition temperature of the independently synthesized block (A1) itself (i.e., the block (A1) not incorporated into the block copolymer (A)).

[0036] By adjusting the glass transition temperature of the block (A1) to fall within the above range, pseudo-crosslinking is formed due to the microphase-separated structure of the block copolymer (A), and adhesive strength tends to be further improved.

[0037] The glass transition temperature of the block (A1) can be adjusted by changing the type and amount of the monomers that constitute the block.

[0038] The glass transition temperature of the block (A1) is measured by the method described in the Examples below.

[0039] The number average molecular weight (Mn) of the block (A1) is preferably 1,000 or more and 90,000 or less, more preferably 5,000 or more and 70,000 or less, and even more preferably 10,000 or more and 50,000 or less.

[0040] The weight average molecular weight (Mw) of the block (A1) is preferably 1,000 or more and 100,000 or less, more preferably 5,000 or more and 90,000 or less, and even more preferably 10,000 or more and 70,000 or less.

[0041] The molecular weight distribution (Mw / Mn) of the block (A1) is preferably 1.0 or more and 2.0 or less, more preferably 1.05 or more and 1.9 or less, and even more preferably 1.1 or more and 1.7 or less.

[0042] By setting the Mn, Mw, and / or Mw / Mn of the block (A1) within the above ranges, the adhesive strength tends to be further improved.

[0043] The Mn and Mw of the block (A1) can be measured by converting the molecular weight measured by gel permeation chromatography (GPC) into polystyrene equivalents. When a plurality of blocks (A1) are present, the sum of the Mn or Mw of each block is the Mn or Mw of the block (A1).

[0044] The block (A1) preferably contains a structural unit (A1U1) derived from an imide group-containing vinyl monomer and a structural unit (A1U2) derived from a (meth)acrylic monomer (excluding an imide group-containing vinyl monomer).

[0045] From the viewpoint of obtaining excellent adhesive strength, the total amount of the structural units (A1U1) and (A1U2) is preferably 60% by mass or more, more preferably 80% by mass or more, and even more preferably 90% by mass or more, based on the mass of all structural units in the block (A1). There are no particular limitations on the upper limit of the total amount of the structural units (A1U1) and (A1U2), and it may be, for example, 100% by mass, 90% by mass, or 80% by mass.

[0046] (Structural unit (A1U1) derived from imide group-containing vinyl monomer) The polymer block (A1) preferably contains a structural unit (A1U1) derived from an imide group-containing vinyl monomer, which tends to further improve adhesive strength.

[0047] Examples of the imide group-containing vinyl monomer include: maleimide compounds such as maleimide and N-substituted maleimide compounds; itaconimide compounds such as N-methylitaconimide, N-ethylitaconimide, N-butylitaconimide, N-2-ethylhexylitaconimide, and N-cyclohexylitaconimide; Citraconimide compounds such as N-methylcitraconimide, N-ethylcitraconimide, N-butylcitraconimide, N-2-ethylhexylcitraconimide, and N-cyclohexylcitraconimide; and (meth)acrylimide compounds such as N-(2-(meth)acryloyloxyethyl)succinimide, N-(2-(meth)acryloyloxyethyl)maleimide, N-(2-(meth)acryloyloxyethyl)phthalimide, and N-(4-(meth)acryloyloxybutyl)phthalimide; etc.

[0048] The imide group-containing vinyl monomer is preferably a maleimide compound, and the maleimide compound is preferably a maleimide or N-substituted maleimide compound. Examples of the N-substituted maleimide compound include: N-alkyl-substituted maleimide compounds such as N-methylmaleimide, N-ethylmaleimide, Nn-propylmaleimide, N-isopropylmaleimide, Nn-butylmaleimide, N-isobutylmaleimide, N-tert-butylmaleimide, N-pentylmaleimide, N-hexylmaleimide, N-heptylmaleimide, N-octylmaleimide, N-laurylmaleimide, and N-stearylmaleimide; N-cycloalkyl-substituted maleimide compounds such as N-cyclopentylmaleimide and N-cyclohexylmaleimide; N-aralkyl-substituted maleimide compounds such as N-benzylmaleimide; and N-aryl substituted maleimide compounds such as N-phenylmaleimide, N-(4-hydroxyphenyl)maleimide, N-(4-acetylphenyl)maleimide, N-(4-methoxyphenyl)maleimide, N-(4-ethoxyphenyl)maleimide, N-(4-chlorophenyl)maleimide, and N-(4-bromophenyl)maleimide; Examples include:

[0049] From the viewpoint of improving heat resistance and adhesiveness, the imide group-containing vinyl monomer is preferably a compound represented by the following formula (U1). [ka] [R U1 is a hydrogen atom, an alkyl group having 1 to 3 carbon atoms, a cyclohexyl group, a phenyl group, or a substituted phenyl group (the substituent may be, for example, a hydroxy group, an alkoxy group having 1 to 2 carbon atoms, an acetyl group, or a halogen atom).

[0050] The amount of the structural unit (A1U1) is preferably 20% by mass or more and 90% by mass or less, more preferably 30% by mass or more and 80% by mass or less, and even more preferably 40% by mass or more and 70% by mass or less, based on the mass of all structural units in the block (A1).

[0051] (Structural unit (A1U2) derived from (meth)acrylic monomer) The polymer block (A1) preferably contains a structural unit (A1U2) derived from a (meth)acrylic monomer, which tends to further improve adhesive strength.

[0052] Examples of the (meth)acrylic monomer include (meth)acrylic acid, alkyl (meth)acrylate compounds (the alkyl group preferably has 1 to 12 carbon atoms), hydroxyalkyl (meth)acrylate compounds (the alkyl group preferably has 1 to 12 carbon atoms), epoxy group-containing (meth)acrylic acid ester compounds, and silyl group-containing (meth)acrylic acid ester compounds.

[0053] Examples of the alkyl (meth)acrylate compound include methyl (meth)acrylate, ethyl (meth)acrylate, n-propyl (meth)acrylate, isopropyl (meth)acrylate, n-butyl (meth)acrylate, isobutyl (meth)acrylate, n-hexyl (meth)acrylate, n-octyl (meth)acrylate, isooctyl (meth)acrylate, 2-ethylhexyl (meth)acrylate, n-nonyl (meth)acrylate, isononyl (meth)acrylate, n-decyl (meth)acrylate, and lauryl (meth)acrylate.

[0054] Examples of the hydroxyalkyl (meth)acrylate compound include 2-hydroxyethyl (meth)acrylate, 2-hydroxypropyl (meth)acrylate, 3-hydroxypropyl (meth)acrylate, 2-hydroxybutyl (meth)acrylate, 3-hydroxybutyl (meth)acrylate, and 4-hydroxybutyl (meth)acrylate.

[0055] Examples of epoxy group-containing (meth)acrylic acid ester compounds include glycidyl (meth)acrylate, 4-hydroxybutyl (meth)acrylate glycidyl ether, and 3,4-epoxycyclohexylmethyl (meth)acrylate.

[0056] Examples of silyl group-containing (meth)acrylic acid ester compounds include trimethoxysilylpropyl (meth)acrylate, triethoxysilylpropyl (meth)acrylate, methyldimethoxysilylpropyl (meth)acrylate, and dimethylmethoxysilylpropyl (meth)acrylate.

[0057] From the viewpoint of obtaining excellent adhesive strength, the structural unit (A1U2) is preferably a structural unit derived from a compound represented by the following formula (1). CH2=CR 1 -C(=O)O(R 2 O) n -R 3 (1) [R 1is a hydrogen atom or a methyl group, R 2 is a linear or branched alkylene group having 2 to 6 carbon atoms, R 3 is a hydrogen atom or an alkyl group having 1 to 20 carbon atoms, n is an integer of 0 to 100, preferably 0 or 1.

[0058] The amount of the structural unit (A1U2) is preferably 10% by mass or more and 80% by mass or less, more preferably 20% by mass or more and 70% by mass or less, and even more preferably 30% by mass or more and 60% by mass or less, based on the mass of all structural units in the block (A1).

[0059] (Structural units derived from other monomers (A1U3)) The polymer block (A1) may contain a structural unit (A1U3) derived from another monomer. Examples of the structural unit (A1U3) include a structural unit derived from an aromatic vinyl monomer (hereinafter also referred to as an "aromatic vinyl structural unit"). By containing an aromatic vinyl structural unit, adhesive strength tends to be further improved.

[0060] Examples of aromatic vinyl monomers include: Styrenic compounds such as styrene, α-methylstyrene, β-methylstyrene, vinylxylene, o-methylstyrene, m-methylstyrene, p-methylstyrene, o-ethylstyrene, m-ethylstyrene, p-ethylstyrene, p-n-butylstyrene, p-isobutylstyrene, pt-butylstyrene, o-methoxystyrene, m-methoxystyrene, p-methoxystyrene, o-chlorostyrene, m-chlorostyrene, p-chlorostyrene, p-hydroxystyrene, m-hydroxystyrene, o-hydroxystyrene, p-isopropenylphenol, m-isopropenylphenol, o-isopropenylphenol, o-vinylbenzoic acid, m-vinylbenzoic acid, p-vinylbenzoic acid, and divinylbenzene; and vinylnaphthalene; Examples include:

[0061] When the polymer block (A1) contains structural units derived from an aromatic vinyl monomer, the amount of the aromatic vinyl structural units is preferably from 5 to 70% by mass, more preferably from 10 to 60% by mass, and even more preferably from 20 to 50% by mass, based on the mass of all structural units in the block (A1).

[0062] [(Meth)acrylic polymer block (A2)] The block copolymer (A) contains a (meth)acrylic polymer block (A2).

[0063] The glass transition temperature of the block (A2) is preferably −80° C. or higher and lower than 10° C., more preferably −70° C. or higher and 0° C. or lower, even more preferably −60° C. or higher and −10° C. or lower, and particularly preferably −50° C. or higher and −20° C. The glass transition temperature of the block (A2) refers to the glass transition temperature of the independently synthesized block (A2) itself (i.e., the block (A2) not incorporated into the block copolymer (A)).

[0064] By adjusting the glass transition temperature of the block (A2) to fall within the above range, the adhesive strength tends to be further improved.

[0065] The glass transition temperature of the block (A2) can be adjusted by changing the type and amount of the monomers that constitute the block.

[0066] The method for measuring the glass transition temperature of the block (A2) is as described in the Examples below.

[0067] (Structural unit (A2U1) derived from (meth)acrylic acid ester) The (meth)acrylic polymer block (A2) preferably contains a structural unit (A2U1) derived from a (meth)acrylic acid ester, which tends to further improve adhesive strength.

[0068] Examples of (meth)acrylic acid esters include alkyl (meth)acrylate compounds (the alkyl group preferably has 1 to 12 carbon atoms), hydroxyalkyl (meth)acrylate compounds (the alkyl group preferably has 1 to 12 carbon atoms), and alkoxyalkyl (meth)acrylate compounds (the alkoxyalkyl group preferably has 2 to 12 carbon atoms).

[0069] Specific examples of the alkyl (meth)acrylate compound and the hydroxyalkyl (meth)acrylate compound are as described above in the description of the structural unit (A1U2).

[0070] Examples of the alkoxyalkyl (meth)acrylate compound include methoxymethyl (meth)acrylate, ethoxymethyl (meth)acrylate, butoxymethyl (meth)acrylate, methoxyethyl (meth)acrylate, ethoxyethyl (meth)acrylate, butoxyethyl (meth)acrylate, methoxybutyl (meth)acrylate, ethoxybutyl (meth)acrylate, and butoxybutyl (meth)acrylate.

[0071] The amount of the structural unit (A2U1) is preferably 15% by mass or more, more preferably 50% by mass or more, even more preferably 70% by mass or more, and particularly preferably 90% by mass or more, based on the mass of all structural units in the block (A2). The upper limit of the amount of the structural unit (A2U1) is not particularly limited, and may be, for example, 100% by mass, 98% by mass, 95% by mass, or 93% by mass.

[0072] (Structural units derived from other monomers (A2U2)) The polymer block (A2) may contain a structural unit (A2U2) derived from another monomer, such as (meth)acrylic acid or a (meth)acrylamide compound.

[0073] Examples of the (meth)acrylamide compound include (meth)acrylamide, dimethylacrylamide, diethylacrylamide, isopropylacrylamide, and 2-hydroxyethylacrylamide.

[0074] When the polymer block (A2) contains the structural unit (A2U2), the amount of the structural unit (A2U2) is preferably 0.1% by mass or more and 10% by mass or less, more preferably 0.5% by mass or more and 8% by mass or less, and even more preferably 1% by mass or more and 6% by mass or less, based on the mass of all structural units of the block (A2).

[0075] <Vinyl polymer (B)> The pressure-sensitive adhesive composition according to this embodiment may contain a vinyl polymer (B).

[0076] It is preferable that the vinyl polymer (B) is not completely miscible with the block copolymer (A) and does not completely phase separate. The vinyl polymer (B) preferably has a lower polarity than the block copolymer (A). By using such a vinyl polymer (B), when a pressure-sensitive adhesive layer is formed from the pressure-sensitive adhesive composition, the vinyl polymer (B) segregates on the surface of the pressure-sensitive adhesive layer, thereby exhibiting excellent adhesiveness.

[0077] The glass transition temperature of the vinyl polymer (B) is preferably 30°C or higher and 200°C or lower, more preferably 40°C or higher and 180°C or lower, and even more preferably 60°C or higher and 150°C or lower.

[0078] By adjusting the glass transition temperature of the vinyl polymer (B) to fall within the above range, the adhesive strength tends to be further improved.

[0079] The glass transition temperature of the vinyl polymer (B) can be adjusted by changing the type and amount of the monomers that constitute the polymer.

[0080] The glass transition temperature of the vinyl polymer (B) is measured by the method described later in the Examples.

[0081] The number average molecular weight (Mn) of the vinyl polymer (B) is preferably 500 or more and 10,000 or less, more preferably 1,000 or more and 7,000 or less, and even more preferably 1,500 or more and 5,000 or less.

[0082] The weight average molecular weight (Mw) of the vinyl polymer (B) is preferably 1,000 or more and 12,000 or less, more preferably 2,000 or more and 10,000 or less, and even more preferably 3,000 or more and 8,000 or less.

[0083] The molecular weight distribution (Mw / Mn) of the vinyl polymer (B) is preferably 1.0 or more and 3.0 or less, more preferably 1.1 or more and 2.5 or less, and even more preferably 1.2 or more and 2.0 or less.

[0084] By setting the Mn, Mw, and / or Mw / Mn of the vinyl polymer (B) within the above ranges, the degree of segregation of the vinyl polymer (B) on the surface of the pressure-sensitive adhesive layer is suitably controlled, and adhesiveness tends to be further improved.

[0085] The Mn and Mw of the vinyl polymer (B) can be measured by converting the molecular weight measured by gel permeation chromatography (GPC) into polystyrene equivalents.

[0086] The amount of the vinyl polymer (B) is preferably 0.5 to 30 mass %, more preferably 1 to 20 mass %, and even more preferably 3 to 10 mass %, based on the mass of the block copolymer (A).

[0087] If the amount of vinyl polymer (B) is too small, the segregation of the vinyl polymer (B) on the surface of the pressure-sensitive adhesive layer becomes insufficient. If the amount of vinyl polymer (B) is too large, phase separation from the (meth)acrylic polymer (A) tends to occur, resulting in a decrease in adhesiveness. By adjusting the amount of vinyl polymer (B) within the above range, the degree of segregation of the vinyl polymer (B) on the surface of the pressure-sensitive adhesive layer can be suitably adjusted, and adhesiveness tends to be further improved.

[0088] The vinyl polymer (B) preferably contains a structural unit derived from a radically polymerizable vinyl monomer. Examples of the radically polymerizable vinyl monomer include (meth)acrylic acid compounds, aromatic vinyl compounds, unsaturated carboxylic acids, unsaturated acid anhydrides, hydroxyl group-containing unsaturated compounds, amino group-containing unsaturated compounds, amide group-containing unsaturated compounds, alkoxyl group-containing unsaturated compounds, cyano group-containing unsaturated compounds, nitrile group-containing unsaturated compounds, and maleimide compounds.

[0089] Examples of (meth)acrylic acid compounds include methyl (meth)acrylate, ethyl (meth)acrylate, n-propyl (meth)acrylate, isopropyl (meth)acrylate, n-butyl (meth)acrylate, isobutyl (meth)acrylate, tert-butyl (meth)acrylate, amyl (meth)acrylate, n-hexyl (meth)acrylate, n-octyl (meth)acrylate, ethylhexyl (meth)acrylate, n-dodecyl (meth)acrylate, n-octadecyl (meth)acrylate, cyclohexyl (meth)acrylate, methylcyclohexyl (meth)acrylate, tert-butylcyclohexyl (meth)acrylate, cyclododecyl (meth)acrylate, isobornyl (meth)acrylate, adamantyl (meth)acrylate, dicyclopentenyl (meth)acrylate, dicyclopentanyl (meth)acrylate, phenyl (meth)acrylate, and benzyl (meth)acrylate.

[0090] Examples of aromatic vinyl compounds include styrene, α-methylstyrene, o-methylstyrene, p-methylstyrene, vinyltoluene, β-methylstyrene, ethylstyrene, p-tert-butylstyrene, vinylxylene, and vinylnaphthalene.

[0091] Examples of unsaturated carboxylic acids include (meth)acrylic acid, ethacrylic acid, maleic acid, fumaric acid, itaconic acid, crotonic acid, citraconic acid, cinnamic acid, and monoalkyl esters of unsaturated dicarboxylic acids (maleic acid, fumaric acid, itaconic acid, citraconic acid, maleic anhydride, itaconic anhydride, citraconic anhydride, etc.).

[0092] Unsaturated acid anhydrides include, for example, maleic anhydride, itaconic anhydride, and citraconic anhydride.

[0093] Examples of hydroxyl group-containing unsaturated compounds include 2-hydroxyethyl (meth)acrylate, 2-hydroxypropyl (meth)acrylate, 3-hydroxypropyl (meth)acrylate, 2-hydroxybutyl (meth)acrylate, 3-hydroxybutyl (meth)acrylate, 4-hydroxybutyl (meth)acrylate, mono(meth)acrylic acid esters of polyalkylene glycols (polyethylene glycol, polypropylene glycol, etc.), p-hydroxystyrene, m-hydroxystyrene, o-hydroxystyrene, p-isopropenylphenol, m-isopropenylphenol, and o-isopropenylphenol.

[0094] Examples of amino group-containing unsaturated compounds include dimethylaminomethyl (meth)acrylate, diethylaminomethyl (meth)acrylate, 2-dimethylaminoethyl (meth)acrylate, 2-diethylaminoethyl (meth)acrylate, 2-(di-n-propylamino)ethyl (meth)acrylate, 2-dimethylaminopropyl (meth)acrylate, 2-diethylaminopropyl (meth)acrylate, 2-(di-n-propylamino)propyl (meth)acrylate, 3-dimethylaminopropyl (meth)acrylate, 3-diethylaminopropyl (meth)acrylate, and 3-(di-n-propylamino)propyl (meth)acrylate.

[0095] Examples of the amide group-containing unsaturated compound include (meth)acrylamide, N,N-dimethyl(meth)acrylamide, N,N-dimethylaminopropyl(meth)acrylamide, and N-methylol(meth)acrylamide.

[0096] Examples of alkoxyl group-containing unsaturated compounds include 2-methoxyethyl (meth)acrylate, 2-ethoxyethyl (meth)acrylate, 2-(n-propoxy)ethyl (meth)acrylate, 2-(n-butoxy)ethyl (meth)acrylate, 3-methoxypropyl (meth)acrylate, 3-ethoxypropyl (meth)acrylate, 2-(n-propoxy)propyl (meth)acrylate, and 2-(n-butoxy)propyl (meth)acrylate.

[0097] Examples of cyano group-containing unsaturated compounds include cyanomethyl (meth)acrylate, 1-cyanoethyl (meth)acrylate, 2-cyanoethyl (meth)acrylate, 1-cyanopropyl (meth)acrylate, 2-cyanopropyl (meth)acrylate, 3-cyanopropyl (meth)acrylate, 4-cyanobutyl (meth)acrylate, 6-cyanohexyl (meth)acrylate, 2-ethyl-6-cyanohexyl (meth)acrylate, and 8-cyanooctyl (meth)acrylate.

[0098] Examples of the nitrile group-containing unsaturated compound include (meth)acrylonitrile, ethacrylonitrile, α-ethylacrylonitrile, α-isopropylacrylonitrile, α-chloroacrylonitrile, and α-fluoroacrylonitrile.

[0099] Examples of maleimide compounds include maleimide, N-methylmaleimide, N-isopropylmaleimide, N-butylmaleimide, N-dodecylmaleimide, N-cyclohexylmaleimide, N-phenylmaleimide, N-(2-methylphenyl)maleimide, N-(4-methylphenyl)maleimide, N-(2,6-dimethylphenyl)maleimide, N-(2,6-diethylphenyl)maleimide, N-benzylmaleimide, and N-naphthylmaleimide.

[0100] From the viewpoint of obtaining suitable compatibility with the (meth)acrylic polymer (A), the radically polymerizable vinyl monomer preferably contains a (meth)acrylic acid compound.

[0101] The amount of structural units derived from (meth)acrylic acid compounds is preferably 10% by mass or more, more preferably 30% by mass or more, even more preferably 50% by mass or more, and particularly preferably 70% by mass or more, based on the mass of all structural units in the vinyl polymer (B). The upper limit of the amount of structural units derived from (meth)acrylic acid compounds is not particularly limited, and may be, for example, 100%, 95%, 90%, or 80% by mass.

[0102] <Nanocellulose> The pressure-sensitive adhesive composition according to this embodiment contains nanocellulose. By using nanocellulose, adhesive strength can be improved.

[0103] The amount of nanocellulose is preferably 0.1 to 20 mass %, more preferably 0.5 to 15 mass %, and even more preferably 1 to 10 mass %, based on the mass of the block copolymer (A). By setting the amount of nanocellulose within the above range, the adhesive strength can be further improved.

[0104] The nanocellulose may be modified nanocellulose. Modified nanocellulose can be obtained, for example, by reacting nanocellulose with a modifying group-introducing compound described below. Nanocellulose is cellulose that has been nanosized. Nanocellulose can be obtained, for example, by oxidizing and nanoizing a cellulosic raw material. The order of oxidation and nanoization is not particularly limited, but it is preferable to oxidize the cellulosic raw material and then nanoize it. Nanoization tends to be easier by oxidizing the cellulosic raw material first.

[0105] Examples of oxidizing agents for oxidizing cellulosic raw materials include hypochlorous acid or its salts and N-oxyl compounds, such as 2,2,6,6-tetramethylpiperidine-1-oxyl (TEMPO).

[0106] From the viewpoint of exerting excellent adhesive strength, it is preferable to use hypochlorous acid or its salt as the oxidizing agent. In other words, nanocellulose is preferably produced by oxidizing a cellulosic raw material with hypochlorous acid or its salt (without using an N-oxyl compound) and nano-sizing the resulting oxidized cellulose.

[0107] The following description focuses on the oxidation of cellulosic raw materials with hypochlorous acid or its salts, but nanocellulose is not limited to nanocellulose with hypochlorous acid or its salts.

[0108] [Oxidized cellulose] Unless otherwise specified, "oxidized cellulose" in this section below refers to an oxidation product of a cellulose-based raw material with hypochlorous acid or a salt thereof before defibration.

[0109] Examples of hypochlorous acid or salts thereof include hypochlorous acid water, sodium hypochlorite, potassium hypochlorite, calcium hypochlorite, and ammonium hypochlorite.

[0110] The amount of hypochlorous acid or its salt used is not particularly limited, but it is preferable to use it so that the available chlorine concentration in the reaction system is 6 to 43 mass %. The available chlorine concentration may be a low concentration of 6 to 14 mass %, or a high concentration of 14 to 43 mass %.

[0111] The definition of the effective chlorine concentration of hypochlorous acid or a salt thereof is as described in WO 2022 / 009979.

[0112] The cellulosic raw material is not particularly limited as long as it is a material primarily composed of cellulose, and examples thereof include pulp, natural cellulose, and fine cellulose obtained by depolymerizing cellulose through mechanical processing. The cellulosic raw material preferably has a type I crystal structure. As the cellulosic raw material, commercially available products such as crystalline cellulose made from pulp can be used as is. Alternatively, unused biomass containing a large amount of cellulose components, such as soybean pulp refuse or soybean hulls, may also be used as the raw material. Furthermore, the cellulosic raw material may be pre-treated with an alkali of an appropriate concentration in order to facilitate the penetration of the oxidizing agent used into the raw pulp. The main component of plants is cellulose, and bundles of cellulose molecules are called cellulose microfibrils. The cellulose in cellulosic raw materials is also contained in the form of cellulose microfibrils.

[0113] (N-oxyl compounds) Preferably, oxidized cellulose is substantially free of N-oxyl compounds. By being substantially free of N-oxyl compounds, the impact on the environment and human body is sufficiently reduced, resulting in a high level of safety. Examples of N-oxyl compounds include 2,2,6,6-tetramethylpiperidine-1-oxyl (TEMPO).

[0114] As used herein, "substantially free of N-oxyl compounds" means that no N-oxyl compounds are used in the production of oxidized cellulose, that the oxidized cellulose contains no N-oxyl compounds at all, or that the content of N-oxyl compounds is 2.0 ppm by mass or less, and preferably 1.0 ppm by mass or less, relative to the total amount of oxidized cellulose. In addition, when the content of N-oxyl compounds is, as an increase from the cellulosic raw material, preferably 2.0 mass ppm or less, more preferably 1.0 mass ppm or less, it is also considered to be "substantially free of N-oxyl compounds."

[0115] The content of N-oxyl compounds can be measured by known means, such as a method using a trace total nitrogen analyzer (for example, TN-2100H manufactured by Nitto Seiko Analytech Co., Ltd.).

[0116] (carboxyl group amount) The amount of carboxy groups in the oxidized cellulose is preferably 0.1 to 3.0 mmol / g, more preferably 0.2 to 2.0 mmol / g, even more preferably 0.3 to 1.5 mmol / g, particularly preferably 0.4 to 1.2 mmol / g, and most preferably 0.5 to 0.9 mmol / g.

[0117] The amount of carboxy groups in oxidized cellulose can be measured by the method described in WO 2022 / 009979.

[0118] Oxidized cellulose preferably has a structure in which at least two of the hydroxyl groups on the glucopyranose ring that constitutes cellulose are oxidized, and more specifically, it preferably has a structure in which the hydroxyl groups at the second and third positions on the glucopyranose ring are oxidized and dicarboxyl groups are introduced. It is also preferable that the hydroxyl group at the sixth position on the glucopyranose ring is not oxidized and remains as a hydroxyl group. The position of the carboxyl group on the glucopyranose ring is determined by the solid 13 It can be analyzed by C-NMR spectroscopy.

[0119] Rayon has the same chemical structure as cellulose, and its oxide (rayon oxide) is water-soluble. 13 By C-NMR measurement, a carbon peak attributable to the carboxy group is observed at 165 to 185 ppm. In one embodiment of the oxidation of a cellulosic raw material with hypochlorous acid or its salt, two signals appear in this chemical shift range. Furthermore, by solution two-dimensional NMR measurement, it can be determined that the carboxy groups are introduced at the 2- and 3-positions.

[0120] Solid oxide of cellulosic raw materials with hypochlorous acid or its salts 13 In C-NMR, when the amount of carboxyl groups introduced is large, two signals appear at 165 to 185 ppm, and when the amount of carboxyl groups introduced is small, a very broad signal may appear. As can be seen from the results for oxidized rayon, the signals of the carboxyl group carbons introduced at the 2nd and 3rd positions are close to each other, and this is difficult to achieve with low-resolution solid state spectroscopy. 13 In C-NMR, the separation of the two signals is insufficient. Therefore, when the amount of carboxyl group introduced is small, a broad signal is observed. 13 In the C-NMR spectrum, the introduction of carboxy groups at the 2nd and 3rd positions can be confirmed by evaluating the broadening of the peaks appearing at 165 to 185 ppm.

[0121] That is, solid 13 A baseline is drawn around the peak in the range of 165 ppm to 185 ppm in the C-NMR spectrum to determine the overall area value, and then the area value is vertically divided at the peak top to determine the ratio of the two peak area values ​​(large area value / small area value). If the ratio of the peak area values ​​is 1.2 or more, the peak can be said to be broad. The presence or absence of the broad peak can be determined by the ratio of the length L of the baseline in the range of 165 ppm to 185 ppm to the length L' of the perpendicular line from the peak top to the baseline. That is, if the ratio L' / L is 0.1 or more, it can be determined that a broad peak is present. The ratio L' / L may be 0.2 or more, 0.3 or more, 0.4 or more, or even 0.5 or more. There is no particular upper limit to the ratio L' / L, but it is usually 3.0 or less, and may be 2.0 or less, or 1.0 or less.

[0122] The structure of the glucopyranose ring can also be determined by analysis according to the method described in Sustainable Chem. Eng. 2020, 8, 48, 17800-17806.

[0123] (Viscosity average degree of polymerization) The viscosity average degree of polymerization of the oxidized cellulose is preferably 30-500, more preferably 60-300, even more preferably 70-150, and particularly preferably 80-130.

[0124] The viscosity average degree of polymerization is the average degree of polymerization measured by a viscosity method. The viscosity average degree of polymerization can be measured by the method described in WO 2022 / 009979.

[0125] [Method of producing oxidized cellulose] Oxidized cellulose can be produced by oxidizing a cellulosic raw material with hypochlorous acid or a salt thereof. Specific production methods include those described in WO 2022 / 009979 and WO 2022 / 009980. Oxidized cellulose is also available commercially, such as Aronfibro (registered trademark) manufactured by Toagosei Co., Ltd.

[0126] [Nanocellulose] Unless otherwise specified, "nanocellulose" in this section hereinafter refers to an oxide of a cellulose-based raw material with hypochlorous acid or its salt, after defibration.

[0127] Nanocellulose is a general term for micronized cellulose, and includes micronized cellulose fibers and cellulose nanocrystals. Micronized cellulose fibers are also called cellulose nanofibers (also referred to as CNF).

[0128] Nanocellulose preferably has a carboxyl group. The carboxyl group may be in the H type (-COOH) or in the salt type. The type of salt is not particularly limited, but examples include alkali metal salts such as lithium salt, sodium salt, and potassium salt; alkaline earth metal salts such as calcium salt and barium salt; other metal salts such as magnesium salt and aluminum salt; ammonium salt; and organic amine salts.

[0129] Nanocellulose is a collection of individual fibers. When nanocellulose contains carboxylated nanocellulose, it is sufficient that it contains at least one carboxylated nanocellulose, and it is preferable that carboxylated nanocellulose is the main component. Here, carboxylated nanocellulose being the main component means that the proportion of carboxylated nanocellulose in the total amount of nanocellulose exceeds 50% by mass, preferably exceeds 70% by mass, and more preferably exceeds 80% by mass. The upper limit of the above proportion is 100% by mass, but it may also be 98% by mass or 95% by mass.

[0130] (N-oxyl compounds) It is preferable that nanocellulose is substantially free of N-oxyl compounds. The meaning of "substantially free of N-oxyl compounds" and the method for measuring the content of N-oxyl compounds are as described in the above [Oxidized Cellulose] (N-oxyl Compounds) section.

[0131] (carboxyl group amount) The amount of carboxyl groups in nanocellulose, the method for measuring them, and the position at which the carboxyl groups are introduced shall follow the description in the (Carboxy group amount) section of [Oxidized Cellulose] above.

[0132] (average fiber length) The average fiber length of nanocellulose is preferably 50 to 3000 nm, more preferably 50 to 700 nm, even more preferably 50 to 500 nm, still more preferably 60 to 300 nm, and particularly preferably 70 to 200 nm.

[0133] (average fiber width) The average fiber width of nanocellulose is preferably 1 to 20 nm, more preferably 1 to 15 nm, even more preferably 1 to 10 nm, and particularly preferably 1 to 5 nm.

[0134] The average fiber length and average fiber width of nanocellulose can be measured by the method described in WO 2022 / 009980.

[0135] (aspect ratio) The aspect ratio of nanocellulose (average fiber length / average fiber width) is preferably 20-1000, more preferably 20-200, even more preferably 30-190, and particularly preferably 40-180.

[0136] The average fiber length, average fiber width, and aspect ratio of the modified nanocellulose are preferably in the same range as those of the nanocellulose. The average fiber length, average fiber width, and aspect ratio of the modified nanocellulose can also be measured in accordance with the description of WO 2022 / 009980, as in the measurement of nanocellulose.

[0137] (zeta potential) The zeta potential of nanocellulose is preferably -30 mV or less, more preferably -90 mV or more and -30 mV or less, even more preferably -80 mV or more and -30 mV or less, even more preferably -70 mV or more and -30 mV or less, and particularly preferably -65 mV or more and -35 mV or less.

[0138] The zeta potential can be measured by the method described in WO 2022 / 009980.

[0139] (crystallinity) The crystallinity of the nanocellulose is preferably 10 to 70%, more preferably 20 to 70%, even more preferably 30 to 65%, particularly preferably 40 to 60%, and most preferably 50 to 55%.

[0140] The crystallinity can be measured by the method described in WO 2022 / 138759.

[0141] [Method of manufacturing nanocellulose] Nanocellulose can be produced by defibrating the above-mentioned oxidized cellulose. Specific production methods include those described in International Publication Nos. 2022 / 009979 and 2022 / 009980. Nanocellulose can also be obtained by defibrating commercially available oxidized cellulose (e.g., Aronfibro (registered trademark) manufactured by Toagosei Co., Ltd.).

[0142] [Modifying group] The nanocellulose may be modified nanocellulose in which a modifying group has been introduced into the nanocellulose. The modifying group may be of one type or of multiple types.

[0143] (First modifying group) The modified nanocellulose may have a first modifying group introduced into at least some of the hydroxyl groups of the nanocellulose. The hydroxyl groups to which the first modifying group has been introduced are preferably primary hydroxyl groups.

[0144] The bond between the first modifying group and nanocellulose is preferably a covalent bond, more preferably an ester bond. The ester bond is preferably composed of oxygen (O) derived from the hydroxyl group of nanocellulose and a carbonyl group (CO) derived from the first modifying group-introducing compound described below.

[0145] The hydroxyl group of nanocellulose into which the first modifying group has been introduced is preferably represented by the following formula (2). RC(=O)-O- (2)

[0146] In formula (1), R is a substituted or unsubstituted alkyl group, a substituted or unsubstituted cycloalkyl group, a substituted or unsubstituted alkenyl group, or a substituted or unsubstituted cycloalkenyl group. The alkyl group may be linear or branched. The alkenyl group may be linear or branched.

[0147] The alkyl group for R preferably has 1 to 6 carbon atoms, more preferably 1 to 3 carbon atoms, and even more preferably 1 or 2 carbon atoms.

[0148] The cycloalkyl group for R preferably has 3 to 14 carbon atoms, more preferably 4 to 10 carbon atoms, and even more preferably 5 to 6 carbon atoms.

[0149] The alkenyl group for R preferably has 2 to 8 carbon atoms, more preferably 2 to 5 carbon atoms, and even more preferably 2 to 3 carbon atoms.

[0150] The cycloalkenyl group for R preferably has 3 to 14 carbon atoms, more preferably 4 to 10 carbon atoms, and even more preferably 5 to 6 carbon atoms.

[0151] Examples of the substituents of the alkyl group, cycloalkyl group, alkenyl group, and cycloalkenyl group of R include a carboxy group.

[0152] (First modifying group-introducing compound) The first modifying group-introducing compound is a compound that is reacted with nanocellulose to introduce the first modifying group into the hydroxyl group of the nanocellulose. The first modifying group-introducing compound is preferably a carboxylic acid compound.

[0153] Examples of the carboxylic acid compound include saturated monocarboxylic acid compounds, saturated dicarboxylic acid compounds, monocarboxylic acid compounds having an unsaturated bond (hereinafter simply referred to as "unsaturated monocarboxylic acid compounds"), and dicarboxylic acid compounds having an unsaturated bond (hereinafter simply referred to as "unsaturated dicarboxylic acid compounds"). In this specification, the carboxylic acid compound also includes its acid anhydride.

[0154] Saturated monocarboxylic acid compounds include, for example, formic acid, acetic acid, propionic acid, and butyric acid.

[0155] Examples of saturated dicarboxylic acid compounds include succinic acid, glutaric acid, adipic acid, suberic acid, and sebacic acid.

[0156] Examples of unsaturated monocarboxylic acid compounds include (meth)acrylic acid, 2-ethylacrylic acid, 2-propylacrylic acid, and 2-isopropylacrylic acid.

[0157] Examples of unsaturated dicarboxylic acid compounds include maleic acid, fumaric acid, itaconic acid, and alkenyl-substituted succinic acid.

[0158] The first modifying group is preferably a group derived from a carboxylic acid compound, specifically the residue of a carboxylic acid compound that is attached to the nanocellulose as a result of reaction of the carboxylic acid compound with the nanocellulose.

[0159] (Second modifying group) The modified nanocellulose may have a second modifying group introduced into at least some of the carboxy groups of the nanocellulose, and the bond between the second modifying group and the nanocellulose is preferably an ionic bond.

[0160] The second modifying group preferably has an amino group. Preferably, an ionic bond is formed between the amino group of the second modifying group and a carboxyl group of the nanocellulose. The amino group of the second modifying group may be in the form of an ammonium ion.

[0161] The second modifying group can be introduced by reacting nanocellulose having a carboxy group with a second modifying group-introducing compound having an amino group. The second modifying group can also be expressed as a second modifying group-introducing compound that is ionically bonded to the carboxy group of nanocellulose. The second modifying group-introducing compound will be described below, but the second modifying group may have the same structure as the second modifying group-introducing compound, except for the ionic bond with nanocellulose.

[0162] (Second modifying group-introducing compound) The second modifying group-introducing compound is a compound that is reacted with nanocellulose to introduce a second modifying group into the carboxyl group of the nanocellulose. The second modifying group-introducing compound preferably has an amino group.

[0163] The number of amino groups per molecule is, for example, 1 to 4, 1 to 3, 1 or 2, or 1.

[0164] The second modifying group-introducing compound preferably has a long-chain linear or long-chain branched structure. The amino group is preferably located at the terminal of the molecule. The amino group may be located at only one terminal of the molecule, at multiple terminals of the molecule, or at all terminals of the molecule.

[0165] The second modifying group-introducing compound preferably has an oxyalkylene group, more preferably has multiple oxyalkylene groups (polyoxyalkylene groups). In this specification, a compound having an amino group and a polyoxyalkylene group is referred to as a polyetheramine.

[0166] The oxyalkylene group is preferably an oxyalkylene group having 1 to 6 carbon atoms, more preferably an oxyalkylene group having 2 to 4 carbon atoms, and even more preferably an oxyalkylene group having 2 or 3 carbon atoms.

[0167] The oxyalkylene group preferably contains at least one selected from the group consisting of an oxyethylene group, an oxypropylene group, and an oxybutylene group, and more preferably contains an oxyethylene group and / or an oxypropylene group.

[0168] The number of repeating units of the oxyalkylene group is preferably 5-70, more preferably 10-50, and even more preferably 20-45.

[0169] The weight-average molecular weight of the second modifying group-introducing compound is preferably 200 to 5000, more preferably 300 to 4000, and even more preferably 400 to 2500. The weight-average molecular weight can be measured by gel permeation chromatography (GPC).

[0170] <Optional ingredients> The pressure-sensitive adhesive composition according to the present embodiment may contain any additives. Examples of the additives include antioxidants, ultraviolet absorbers, antiaging agents, flame retardants, antifungal agents, silane coupling agents, fillers, colorants, and solvents. The additives may or may not contain a crosslinking agent.

[0171] <Application> The pressure-sensitive adhesive composition according to this embodiment is preferably used to adhere objects (adherends), such as textile fabrics, flexible conductive sheets, and elastomer materials.

[0172] <<Adhesive sheet>> One embodiment of the present invention relates to a pressure-sensitive adhesive sheet comprising the pressure-sensitive adhesive composition described above.

[0173] The PSA sheet preferably includes a PSA composition and a substrate. The PSA composition is preferably disposed on the surface of the substrate. When the substrate is porous, the PSA composition may be disposed on the surface of the substrate, inside the substrate, or both.

[0174] Examples of the substrate include a resin film, paper, cloth, and metal foil. Examples of the material for the resin film include a polyester resin, a polyethersulfone resin, an acetate resin, a polycarbonate resin, and a polyolefin resin.

[0175] The pressure-sensitive adhesive sheet may be the pressure-sensitive adhesive composition itself processed into a sheet shape.

[0176] <<Textile products>> One embodiment of the present invention relates to a textile product adhered with the above-mentioned pressure-sensitive adhesive composition. Examples of textile products include clothing. [Example]

[0177] The present invention will be described in more detail below using examples and comparative examples, but the technical scope of the present invention is not limited to these.

[0178] Various values ​​in the examples may be used as preferred lower or upper limits in the embodiments of the present invention. Two values ​​of the same type in the examples may be appropriately combined to form a preferred numerical range.

[0179] <Synthesis of Block Copolymer (A)> [Synthesis Example A1] (Synthesis of Polymer A-1) A four-neck flask equipped with a stirrer and thermometer was charged with dibenzyl trithiocarbonate (hereinafter referred to as "DBTTC") (1.59 parts by mass) as a RAFT agent, 2,2'-azobis(2-methylbutyronitrile) (hereinafter also referred to as "ABN-E") (0.255 parts by mass) as a polymerization initiator, styrene (hereinafter also referred to as "St") (37.0 parts by mass) as a monomer, and N-phenylmaleimide (hereinafter also referred to as "PhMI") (63.0 parts by mass), and acetonitrile (233.0 parts by mass) as a solvent. The mixture was thoroughly degassed by nitrogen bubbling, and polymerization was initiated in a thermostatic chamber at 70 °C. After 3 hours, the reaction was stopped by cooling to room temperature. The polymer solution was purified by reprecipitation with methanol and vacuum dried to obtain polymer block A1. Polymer block A1 had an Mn of 10,900, an Mw of 12,700, and an Mw / Mn of 1.2. The glass transition temperature Tg of the polymer block A1 was 206°C.

[0180] Next, the resulting polymer block A1 (7.0 parts by weight), ABN-E (0.0267 parts by weight) as a polymerization initiator, n-butyl acrylate (hereinafter also referred to as "BA") (17.0 parts by weight), 2-methoxyethyl acrylate (hereinafter also referred to as "MEA") (78.0 parts by weight), and 2-hydroxyethyl acrylate (hereinafter also referred to as "HEA") (5.0 parts by weight) as monomers, and acetonitrile (35.7 parts by weight) as a solvent were charged into a four-neck flask equipped with a stirrer and a thermometer. The mixture was thoroughly degassed by nitrogen bubbling, and polymerization was initiated in a thermostatic oven at 70 ° C. After 6 hours, the mixture was cooled to room temperature, and ethyl acetate was added to adjust the solids concentration to 30% by weight to obtain a pressure-sensitive adhesive solution containing an (A1-A2-A1) triblock copolymer A-1 having the polymer block A1 and the (meth)acrylic polymer block A2. The polymer A-1 thus obtained had an Mn of 160,000, an Mw of 283,000, and an Mw / Mn of 1.8. The glass transition temperature Tg of the polymer A-1 was -35°C.

[0181] In addition, in the synthesis of polymer A-1, a polymer was prepared by using DBTTC in place of polymer block A1 in an amount equal to the amount of the monomer used in the synthesis of polymer block A1. The glass transition temperature Tg of this polymer was −35° C., which was designated as the glass transition temperature of polymer block A2.

[0182] The glass transition temperature Tg was determined by reading the maximum value of tan δ in dynamic shear viscoelasticity measurement. The Tg of the vinyl polymer (B) described below was also determined in the same manner.

[0183] The vinyl polymers described below were measured by DSC under the following conditions. DSC: TA Instrument (Q-100) Temperature rise: 10°C / min Measurement atmosphere: Nitrogen

[0184] [Synthesis Examples A2 to A10] (Synthesis of Polymers A-2 to A-10) The same procedure as in Synthesis Example A1 was performed, except that the types and amounts of raw materials charged into the flask were changed as shown in Table 1, the reaction time for obtaining polymer block A1 was changed to 6 hours, and the solvent was changed to ethyl acetate (Synthesis Examples A2, A3, A6, A8 to A10) or butyl acetate (Synthesis Examples A4, A5, A7), to obtain adhesive solutions containing polymers A-2 to A-10, respectively. In addition, the glass transition temperature of the polymer block A2 was determined in the same manner as in Synthesis Example A1.

[0185] [Table 1]

[0186] The symbols in Table 1 have the following meanings: PhMI: N-phenylmaleimide MA: methyl acrylate EA: Ethyl acrylate BA: n-butyl acrylate HA: 2-ethylhexyl acrylate HEA: 2-hydroxyethyl acrylate St: styrene MEA: 2-Methoxyethyl acrylate AA: acrylic acid HEAA: 2-hydroxyethylacrylamide

[0187] <Synthesis of vinyl polymer (B)> [Synthesis Example B1] (Synthesis of vinyl polymer B-1) A 1-liter four-neck flask was charged with a mixture of butyl acetate (200 parts by mass) and dimethyl 2,2'-azobis(2-methylpropionate) (manufactured by Wako Pure Chemical Industries, Ltd., trade name "V-601") (0.9 parts by mass). The mixture was thoroughly degassed by bubbling nitrogen gas through it, and the internal temperature of the mixture was raised to 90°C. Separately, a mixture of methyl methacrylate (hereinafter referred to as "MMA") (165 parts by mass), isobornyl methacrylate (hereinafter referred to as "IBXMA") (44 parts by mass), V-601 (17 parts by mass), and butyl acetate (90 parts by mass) was added dropwise from a dropping funnel to the flask over 5 hours to carry out polymerization. After completion of the dropwise addition, the polymerization solution was added dropwise to a mixture of methanol (4,800 parts by mass) and distilled water (1,200 parts by mass). The vinyl polymer in the polymerization solution was isolated to obtain vinyl polymer B-1. The polymer composition of the obtained vinyl polymer B-1 was calculated from the charged amounts and the monomer consumption amounts measured by GC, and was found to consist of 80% by mass of MMA and 20% by mass of IBXMA, with Mw of 6700, Mn of 4370, and Mw / Mn of 1.53. Tg was 108°C. The composition and analytical results of vinyl polymer B-1 are shown in Table 2.

[0188] [Synthesis Examples B2 and B3] (Synthesis of Polymers B-2 and B-3) The same procedure as in Synthesis Example B1 was carried out except that the ratio of the raw materials charged into the flask was changed as shown in Table 2, to obtain vinyl polymers B-2 and B-3.

[0189] [Table 2]

[0190] <Production of modified nanocellulose> [Production Example 1] (Acetic acid-modified (acetylated) nanocellulose [N-1]) (oxidation process) A jacketed glass vessel was charged with 500 g of sodium hypochlorite solution with a pH of 12.7 and an available chlorine concentration of 12.5% ​​by mass, and the mixture was heated to 35°C while stirring at 200 rpm using a Shinto Scientific mixer (Three-One Motor, BL600) with three swept-back blades. Then, 47 g of powdered pulp (KC Flock W-100GK) from Nippon Paper Industries Co., Ltd. was added as a cellulosic raw material. After the cellulosic raw material was added, the mixture was stirred at 35°C until the pH dropped to 10.5. Then, a 25% by mass aqueous sodium hydroxide solution was added to maintain the pH at 10.5 during the reaction. The mixture was stirred under the same conditions for a total of 520 minutes after the cellulosic raw material was added. After the reaction was completed, the remaining sodium hypochlorite was inactivated by adding aqueous hydrogen peroxide, and then hydrochloric acid was added to convert the carboxyl groups of the oxidized cellulose from the salt form (-COO-Na) to the proton form (-COO-H), yielding an aqueous dispersion with a pH of 2.5. The solid-liquid separation was carried out by pressure filtration at 0.2 MPa, and then the dispersion was washed with an aqueous hydrochloric acid solution at pH 2.5. Sodium hydroxide was added to the resulting proton-type oxidized cellulose to convert the carboxylic acid groups from the proton-type (-COO-H) back to the salt-type (-COO-Na), yielding an aqueous dispersion of Na-type oxidized cellulose at pH 7.4. The amount of carboxyl groups in the oxidized cellulose was measured to be 0.78 mmol / g. The nitrogen content derived from N-oxyl compounds in the oxidized cellulose was measured as nitrogen using a trace total nitrogen analyzer (TN-2100H, manufactured by Nitto Seiko Analytech Co., Ltd.), and the increase from the raw pulp was calculated to be less than 1 ppm.

[0191] (defibration process) An aqueous dispersion of Na-type oxidized cellulose (7.5% solids by mass) was processed in a homomixer (Primix, Robomix) at 10,000 rpm with 440 g of liquid for 33 minutes to defibrate the oxidized cellulose into nanocellulose, yielding an aqueous nanocellulose dispersion. The resulting aqueous dispersion was adjusted to a pH of 2.0-2.1 by adding 1N hydrochloric acid solution, and then washed twice with pure water using a tabletop multi-rack centrifuge (KOKUSAN, H-40α). The mixture was then washed (substituted) four times with acetone, followed by concentration by suction filtration using a vacuum pump to obtain acetone-substituted H-type nanocellulose.

[0192] (acetylated denaturation) To the acetone-substituted H-type nanocellulose (1 part by mass) obtained in the above defibration process, acetic anhydride (1.5 parts by mass), 70% perchloric acid (0.05 parts by mass), acetone (6.0 parts by mass), and toluene (14.4 parts by mass) were added and stirred at room temperature for 1 hour. Methanol was added to the reaction solution, and the mixture was stirred to stop the reaction. After that, the mixture was washed (substituted) with methanol seven times using a tabletop multi-rack centrifuge (KOKUSAN, H-40α) to obtain acetylated modified H-type nanocellulose N-1.

[0193] [Production Example 2] (Methacrylic acid modified nanocellulose [N-2]) Methacrylic acid-modified H-type nanocellulose N-2 was obtained in the same manner as in Production Example 1, except that acetic anhydride was changed to methacrylic anhydride and the reaction temperature was changed to 50°C.

[0194] [Production Example 3] (Amine-modified nanocellulose [N-3]) To the acetone-substituted H-type nanocellulose obtained by the defibration step in Production Example 1, an amount of JEFFAMINE M-2005 (weight average molecular weight: 2,000, manufactured by Tomoe Engineering Co., Ltd.) equivalent to the acid value was added and stirred. Toluene was added to this, and the solids concentration was adjusted to 5% by mass. The residue was removed by filtration using a filter cloth, and the acetone was distilled off using an evaporator to obtain amine-modified nanocellulose N-3.

[0195] [Production Example 4] (Succinic acid modified nanocellulose [N-4]) To the amine-modified nanocellulose N-3 (1 part by mass) obtained in Production Example 3, succinic anhydride (20 parts by mass) and toluene (42 parts by mass) were added and stirred for 1.5 hours at 90°C. Methanol was added to the reaction solution, and the mixture was stirred to stop the reaction. After that, the mixture was washed (substituted) with methanol seven times using a tabletop multi-rack centrifuge (KOKUSAN, H-40α) to obtain succinic acid-modified H-type nanocellulose N-4.

[0196] [Production Example 5] (Maleic acid-modified nanocellulose [N-5] and itaconic acid-modified nanocellulose [N-6]) Maleic acid-modified H-type nanocellulose [N-5] and itaconic acid-modified H-type nanocellulose [N-6] were obtained in the same manner as in Production Example 4, except that succinic anhydride in Production Example 4 was changed to itaconic anhydride or itaconic anhydride.

[0197] <Preparation of Pressure-Sensitive Adhesive Composition> [Example 1] To block copolymer A-1 (20.0 parts by mass), a 1.0 wt% ethyl acetate dispersion of modified nanocellulose N-1 (20.0 parts by mass) and a 30 wt% ethyl acetate solution of vinyl polymer B-1 (2.67 parts by mass) were added, and the mixture was diluted with ethyl acetate (33.3 parts by mass) to give a blended mixture with a concentration of components excluding the solvent of 26% by mass, thereby obtaining the adhesive composition of Example 1.

[0198] [Examples 2 to 10] The various components were blended to obtain the composition ratios (parts by mass) shown in Table 3, to obtain pressure-sensitive adhesive compositions of Examples 2 to 10. The additive used was KBE-9007N manufactured by Shin-Etsu Silicone Co., Ltd.

[0199] "Rate of increase in peel strength" in Table 3 refers to the rate of increase in peel strength of the Examples relative to the peel strength of the Comparative Examples. Specifically, Examples 1 to 10 are compared with Comparative Examples 2 to 11, respectively.

[0200] [Comparative Example 1] In Comparative Example 1, a polyester-based hot melt adhesive PES310S30 manufactured by Toagosei Co., Ltd. was used.

[0201] [Comparative Examples 2 to 11] Each of the pressure-sensitive adhesive compositions of Comparative Examples 2 to 11 was obtained in the same manner as in Examples 1 to 10, except that modified nanocellulose was not used.

[0202] <Preparation of adhesive film samples> The pressure-sensitive adhesive compositions described in the Examples and Comparative Examples were applied to a 50 μm thick polyethylene terephthalate (hereinafter, "PET") separator so that the thickness after drying would be 50 μm. The pressure-sensitive adhesive composition was dried at 80° C. for 4 minutes to remove ethyl acetate, and a 38 μm thick PET separator with a different peel strength from the separator was attached to obtain various pressure-sensitive adhesive film samples with double-sided separators.

[0203] <Peel strength measurement> The polyester fabrics were bonded together using a 1.0 cm wide adhesive film sample to obtain a laminate consisting of polyester fabric / adhesive film / polyester fabric. The obtained laminate was subjected to a heat press treatment (conditions: 130°C, 3 kg / cm 2 The laminate after compression was used as a test piece, and the T-peel strength was measured using a tensile tester INSTRON 5565A (manufactured by Instron Japan) under conditions of a measurement temperature of 23°C, a test piece width of 10 mm, and a peel rate of 300 mm / min, and this was taken as the adhesive strength.

[0204] <Measurement of storage modulus> 50 μm thick adhesive film samples were laminated to a thickness of 1.0 mm to obtain various evaluation adhesive sheets. This was punched into a circle with a diameter of 8 mm, and the dynamic viscoelasticity was measured using a dynamic shear viscoelasticity device (TA Instruments, Discovery HR20) at a frequency of 1 Hz and a strain of 0.1% while heating from -40 ° C to 200 ° C at a rate of 2 ° C / min, and the storage modulus was read at 23 ° C, 50 ° C, and 120 ° C. Parallel plates with an 8 mm diameter were used for the measurement.

[0205] Table 3

[0206] Table 4

Claims

1. A block copolymer (A), Nanocellulose and Including, The block copolymer (A) is a polymer block (A1), a (meth)acrylic polymer block (A2); and Including, Pressure-sensitive adhesive composition.

2. The glass transition temperature of the polymer block (A1) is 10°C or higher and 220°C or lower. The pressure-sensitive adhesive composition according to claim 1 .

3. the glass transition temperature of the (meth)acrylic polymer block (A2) is −80° C. or higher and lower than 10° C.; The pressure-sensitive adhesive composition according to claim 1 .

4. The polymer block (A1) a structural unit (A1U1) derived from an imide group-containing vinyl monomer; a structural unit (A1U2) derived from a (meth)acrylic monomer (excluding an imide group-containing vinyl monomer); Including, The pressure-sensitive adhesive composition according to claim 1 .

5. the total amount of the structural unit (A1U1) and the structural unit (A1U2) is 60 mass% or more based on the mass of all structural units in the polymer block (A1); The pressure-sensitive adhesive composition according to claim 4.

6. The structural unit (A1U2) is represented by the following formula (1): CH 2 =CR 1 -C(=O)O(R 2 O) n -R 3 (1) [R 1 is a hydrogen atom or a methyl group, R 2 is a linear or branched alkylene group having 2 to 6 carbon atoms, R 3 is a hydrogen atom or an alkyl group having 1 to 20 carbon atoms, n is an integer from 0 to 100. The structural unit derived from the compound represented by The pressure-sensitive adhesive composition according to claim 4.

7. the pressure-sensitive adhesive layer formed from the pressure-sensitive adhesive composition has a storage modulus at 23°C of 1.0 MPa or less; The pressure-sensitive adhesive composition according to claim 1 .

8. the (meth)acrylic polymer block (A2) contains a structural unit (A2U1) derived from a (meth)acrylic acid ester; The pressure-sensitive adhesive composition according to claim 1 .

9. the amount of the structural unit (A2U1) is 15% by mass or more based on the mass of all structural units of the (meth)acrylic polymer block (A2); The pressure-sensitive adhesive composition according to claim 8.

10. The block copolymer (A) is a triblock copolymer as follows: [the block (A1)] - [the block (A2)] - [the block (A1)] Including, The pressure-sensitive adhesive composition according to claim 1 .

11. Further comprising a silane coupling agent, The pressure-sensitive adhesive composition according to claim 1 .

12. The nanocellulose has a modifying group; The pressure-sensitive adhesive composition according to claim 1 .

13. The modifying group is introduced into at least some of the hydroxyl groups of the nanocellulose via a covalent bond; The pressure-sensitive adhesive composition according to claim 12.

14. The hydroxyl group to which the modifying group has been introduced is represented by the following formula (2): RC(=O)-O- (2) wherein R is a substituted or unsubstituted alkyl group, a substituted or unsubstituted cycloalkyl group, a substituted or unsubstituted alkenyl group, or a substituted or unsubstituted cycloalkenyl group. is expressed as The pressure-sensitive adhesive composition according to claim 13.

15. The modifying group is introduced into at least some of the carboxy groups of the nanocellulose via ionic bonding; The pressure-sensitive adhesive composition according to claim 12.

16. the modifying group has an amino group; The pressure-sensitive adhesive composition according to claim 15.

17. The nanocellulose comprises an oxide of a cellulosic raw material with hypochlorous acid or a salt thereof, and is substantially free of N-oxyl compounds; The pressure-sensitive adhesive composition according to claim 1 .

18. The nanocellulose has a structure in which the second and third hydroxyl groups of the glucopyranose ring are oxidized and dicarboxyl groups are introduced, The pressure-sensitive adhesive composition according to claim 1 .

19. Contains no crosslinking agents The pressure-sensitive adhesive composition according to claim 1 .

20. A pressure-sensitive adhesive sheet comprising the pressure-sensitive adhesive composition according to any one of claims 1 to 19.

21. A textile product adhered with the pressure-sensitive adhesive composition according to any one of claims 1 to 19.

Images