Adhesive composition, adhesive sheet, laminate, and glucan derivative

Abstract

The present invention provides a novel adhesive composition comprising a glucan derivative. The adhesive composition according to the present invention contains a glucan derivative G having a glycosidic bond A and a glycosidic bond B having a different bonding manner from the glycosidic bond A. The glycosidic bond A is, for example, a 1, 6-glycosidic bond. The pressure-sensitive adhesive sheet (1) is formed from a pressure-sensitive adhesive composition. This laminate (10) is provided with an adhesive sheet (1) and a base sheet (2).

Description

Technical Field

[0001] The present invention relates to an adhesive composition, an adhesive sheet, a laminate and a dextran derivative. Background Art

[0002] In recent years, from the perspective of reducing environmental load, research has been conducted on bioplastics that utilize renewable resources. As renewable resources, for example, polysaccharides derived from organisms and plants are known. As specific examples of such polysaccharides, glucans containing glucose (specifically D-glucose) as a constituent sugar can be cited.

[0003] From the perspective of effectively utilizing glucan, studies have been conducted on the synthesis of glucan derivatives by introducing substituents into glucan. For example, Patent Document 1 studies the synthesis of glucan derivatives by introducing substituents into paramylon, a type of glucan. It should be noted that paramylon is a β-1,3-glucan synthesized by photosynthesis of microalgae such as Euglena, and has no glycosidic bonds other than β-1,3-glycosidic bonds.

[0004] Prior art literature

[0005] Patent Literature

[0006] Patent Document 1: Japanese Patent No. 7012984 Summary of the invention

[0007] Problem that the invention aims to solve

[0008] From the viewpoint of reducing environmental load, new PSA compositions containing glucan derivatives are desired.

[0009] Solutions for solving problems

[0010] The present inventors have conducted intensive research and found that when a PSA composition is prepared using a paramylon derivative, there is room for improvement in the peeling strength of a PSA sheet formed from the PSA composition. Based on this finding, the present inventors have advanced their research and newly discovered that the bonding mode of the glycosidic bonds contained in the glucan derivative affects the peeling strength of the PSA sheet, thereby completing the present invention.

[0011] The present invention provides an adhesive composition.

[0012] The invention comprises: a glucan derivative having a glycosidic bond A and a glycosidic bond B whose bonding mode is different from that of the glycosidic bond A.

[0013] The present invention further provides an adhesive sheet,

[0014] It is formed from the above-mentioned adhesive composition.

[0015] The present invention further provides a laminate comprising:

[0016] The above adhesive sheet, and

[0017] Substrate sheet.

[0018] The present invention further provides a dextran derivative having:

[0019] Glycosidic bond A,

[0020] The bonding mode is different from the glycosidic bond A described above, and

[0021] An acyl group having 8 to 16 carbon atoms.

[0022] Effects of the Invention

[0023] According to the present invention, a novel adhesive composition comprising a glucan derivative can be provided. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] Figure 1 This is a cross-sectional view schematically showing a pressure-sensitive adhesive sheet according to one embodiment of the present invention.

[0025] Figure 2 It is a figure for demonstrating the measurement method of the peeling force of a PSA sheet.

[0026] Figure 3 It is a cross-sectional view schematically showing a laminated body according to one embodiment of the present invention.

[0027] Figure 4 It is a cross-sectional view schematically showing a modified example of the stacked body. DETAILED DESCRIPTION

[0028] The adhesive composition according to the first aspect of the present invention includes:

[0029] A glucan derivative having a glycosidic bond A and a glycosidic bond B whose bonding pattern is different from that of the aforementioned glycosidic bond A.

[0030] In a second aspect of the present invention, for example, in the pressure-sensitive adhesive composition according to the first aspect, the glycosidic bond A is a 1,6-glycosidic bond.

[0031] In a third aspect of the present invention, for example, in the PSA composition according to the first or second aspect, the glycosidic bond B is at least one selected from the group consisting of a 1,3-glycosidic bond and a 1,4-glycosidic bond.

[0032] In a fourth aspect of the present invention, for example, in the PSA composition according to any one of the first to third aspects, the ratio of the number of the glycosidic bonds A contained in the glucan derivative to the number of all glycosidic bonds is 10% to 50%.

[0033] In a fifth aspect of the present invention, for example, in the PSA composition according to any one of the first to fourth aspects, the glucan derivative contains an acyl group.

[0034] In a sixth aspect of the present invention, for example, in the pressure-sensitive adhesive composition according to the fifth aspect, the acyl group has 8 to 16 carbon atoms.

[0035] In a seventh aspect of the present invention, for example, in the PSA composition according to the fifth or sixth aspect, the acyl group is represented by the following formula (1).

[0036] RCO-(1)

[0037] In the above formula (1), R is a hydrocarbon group.

[0038] In an eighth aspect of the present invention, for example, in the PSA composition according to any one of the fifth to seventh aspects, in the glucan derivative, the degree of substitution (DS value) of the acyl group is greater than 2.0.

[0039] In a ninth aspect of the present invention, for example, in the PSA composition according to any one of the first to eighth aspects, the glucan derivative includes at least one selected from the group consisting of pullulan derivatives and laminarin derivatives.

[0040] In a tenth aspect of the present invention, for example, in the PSA composition according to any one of the first to ninth aspects, the weight average molecular weight of the glucan derivative is 5,000,000 or less.

[0041] In an eleventh aspect of the present invention, for example, the pressure-sensitive adhesive composition according to any one of the first to tenth aspects further includes a tackifier.

[0042] In a twelfth aspect of the present invention, for example, in the adhesive composition according to the eleventh aspect, the tackifier includes at least one selected from the group consisting of terpene resins, rosin resins, and petroleum resins.

[0043] In a thirteenth aspect of the present invention, for example, the pressure-sensitive adhesive composition according to any one of the first to twelfth aspects further includes a cross-linking agent.

[0044] In a fourteenth aspect of the present invention, for example, in the pressure-sensitive adhesive composition according to the thirteenth aspect, the crosslinking agent includes an isocyanate crosslinking agent.

[0045] A pressure-sensitive adhesive sheet according to a fifteenth aspect of the present invention is formed from the pressure-sensitive adhesive composition according to any one of the first to fourteenth aspects.

[0046] A laminated body according to a sixteenth aspect of the present invention includes:

[0047] A pressure-sensitive adhesive sheet according to a fifteenth aspect, and

[0048] Substrate sheet.

[0049] The glucan derivative according to the seventeenth aspect of the present invention has:

[0050] Glycosidic bond A,

[0051] The bonding mode is different from the glycosidic bond A described above, and

[0052] An acyl group having 8 to 16 carbon atoms.

[0053] Hereinafter, the present invention will be described in detail, but the following description is not intended to limit the present invention to specific embodiments.

[0054] (Embodiment of Adhesive Composition)

[0055] The adhesive composition of the present embodiment includes a glucan derivative G. The glucan derivative G functions as a base polymer in the adhesive composition, for example. The glucan derivative G has a glycosidic bond A and a glycosidic bond B whose bonding method is different from that of the glycosidic bond A. In this specification, "glycosidic bond" is a bond for connecting glucose units to each other, and refers to an α-glycosidic bond and / or a β-glycosidic bond. "Different bonding methods" means that the connection positions of the glucose units of glycosidic bonds A and B are different from each other.

[0056] In the glucan derivative G having glycosidic bonds A and B with different bonding modes, the distance between molecular chains tends to be longer than that of the glucan derivative having a single type of glycosidic bond. As a result, the adhesive composition containing the glucan derivative G tends to have high adhesive strength.

[0057] As an example, glycosidic bond A can be a 1,6-glycosidic bond. In this case, glycosidic bond B is a glycosidic bond other than a 1,6-glycosidic bond, for example, at least one selected from the group consisting of a 1,2-glycosidic bond, a 1,3-glycosidic bond, and a 1,4-glycosidic bond. Glycosidic bond B is preferably at least one selected from the group consisting of a 1,3-glycosidic bond and a 1,4-glycosidic bond. Wherein, glycosidic bonds A and B are not limited to the above combination.

[0058] The ratio P1 of the number of glycosidic bonds A, particularly 1,6-glycosidic bonds, to the number of all glycosidic bonds contained in the glucan derivative G is, for example, 5% or more, and may be 10% or more, 15% or more, 20% or more, 25% or more, or 30% or more. The upper limit of the ratio P1 is not particularly limited, and may be, for example, 70% or 50%. The ratio P1 is preferably 10% to 50%. When the ratio P1 is within the above numerical range, the adhesive composition tends to have sufficient adhesive force for practical use.

[0059] The ratio P2 of the number of glycosidic bonds B, especially glycosidic bonds other than 1,6-glycosidic bonds, to the number of all glycosidic bonds contained in the glucan derivative G is, for example, 95% or less, 90% or less, 85% or less, 80% or less, 75% or less, or further 70% or less. The lower limit of the ratio P2 is not particularly limited, and is, for example, 30% or 50%.

[0060] The glucan derivative G, for example, has a glucose unit U1 connected to a glycosidic bond A. The glucose unit U1 may be connected to a glycosidic bond B or may not be connected to a glycosidic bond B while being connected to the glycosidic bond A. The glucan derivative G may have a glucose unit U1 and a glucose unit U2 connected to a glycosidic bond B. In this specification, glucose units U1 and U2 may be simply referred to as glucose units U.

[0061] In the glucan derivative G, the number of glycosidic bonds (glycosidic bonds A and B) connected to one glucose unit U is usually 1 to 3. It can be said that the glucan derivative G containing the glucose unit U connected to three glycosidic bonds has a branched structure. On the other hand, it can be said that the glucan derivative G composed only of the glucose unit U connected to one glycosidic bond and the glucose unit U connected to two glycosidic bonds does not have a branched structure but has a linear structure.

[0062] The glucose unit U has, for example, a structure in which a substituent is introduced into a part or all of the hydroxyl groups contained in the unsubstituted glucose unit. A specific example of the substituent is an acyl group. In other words, the glucan derivative G has an acyl group as a substituent. As an example, the glucose unit U has an ester group formed by introducing an acyl group into the hydroxyl group.

[0063] The carbon number of the acyl group possessed by the glucan derivative G is, for example, 8 or more, 9 or more, 10 or more, 11 or more, 12 or more, or 13 or more. The carbon number of the acyl group is, for example, 16 or less, 15 or less, or 14 or less. The carbon number of the acyl group is preferably 8 to 16. In this case, the adhesive composition tends to have sufficient adhesive force for practical use and high transparency.

[0064] According to another aspect, the present invention provides a glucan derivative G having:

[0065] Glycosidic bond A,

[0066] Glycosidic bond B having a bonding mode different from glycosidic bond A, and

[0067] An acyl group having 8 to 16 carbon atoms.

[0068] The polysaccharide derivative G is particularly suitable for use in adhesive compositions.

[0069] The acyl group contained in the glucan derivative G is represented by, for example, the following formula (1).

[0070] RCO-(1)

[0071] In formula (1), R is a hydrocarbon group. The hydrocarbon group may have a substituent, but preferably has no substituent. The number of carbon atoms in the hydrocarbon group is, for example, 7 or more, 8 or more, 9 or more, 10 or more, 11 or more, or 12 or more. The number of carbon atoms in the hydrocarbon group is, for example, 15 or less, 14 or less, or 13 or less. The number of carbon atoms in the hydrocarbon group is preferably 7 to 15.

[0072] Examples of the hydrocarbon group include aliphatic hydrocarbon groups, alicyclic hydrocarbon groups, and aromatic hydrocarbon groups, and aliphatic hydrocarbon groups are preferred. The aliphatic hydrocarbon group may be branched, but is preferably straight-chain. Examples of the aliphatic hydrocarbon group include saturated aliphatic hydrocarbon groups and unsaturated aliphatic hydrocarbon groups, and saturated aliphatic hydrocarbon groups (alkyl groups) are preferred. Examples of the unsaturated aliphatic hydrocarbon group include alkenyl groups.

[0073] Examples of the alkyl group include a heptyl group, an octyl group, a nonyl group, a decyl group, an undecyl group, a dodecyl group, a tridecyl group, a tetradecyl group, and a pentadecyl group.

[0074] Specific examples of the acyl group represented by the formula (1) include octanoyl, nonanoyl, decanoyl, lauroyl, myristoyl, and palmitoyl.

[0075] In the dextran derivative G, the degree of substitution (DS value) of the acyl group is, for example, greater than 2.0, preferably greater than 2.3, greater than 2.4, greater than 2.5, greater than 2.6, greater than 2.7, greater than 2.8, greater than 2.9, and further greater than 3.0. When the DS value of the acyl group is as large as this, the interaction between the molecular chains in the dextran derivative G is weakened, and there is a tendency for the adhesive force of the adhesive composition to increase. When the DS value of the acyl group is greater than 2.0, the number of hydroxyl groups (OH groups) remaining in the dextran derivative G is small, so when the adhesive sheet is formed by the adhesive composition, the situation where the adhesive sheet becomes excessively hard due to the influence of hydrogen bonds can also be suppressed. Among them, the DS value of the acyl group can be lower than 3.0, can be less than 2.9, and can be less than 2.8 depending on the situation. In this case, when the adhesive sheet is formed by the adhesive composition, the hydroxyl groups remaining in the dextran derivative G can react with the cross-linking agent described later.

[0076] It should be noted that the DS value specifically refers to the number of acyl groups for one glucose unit U contained in the glucan derivative G. When the DS value is 3, it can be said that the glucan derivative G has a structure in which acyl groups are basically introduced into the hydroxyl groups contained in the unsubstituted glucose unit. The DS value can be determined by performing nuclear magnetic resonance spectroscopy analysis on the glucan derivative G ( 1In detail, the glucan derivative G was subjected to 1 H-NMR is used to obtain an NMR spectrum. From the obtained NMR spectrum, peaks derived from hydrogen atoms directly bonded to carbon atoms at positions 1 to 6 in the glucose unit U of the dextran derivative G and peaks derived from acyl groups are determined. The DS value can be determined based on the integrated values ​​of these peaks.

[0077] The glucan derivative G can be classified into an α-glucan derivative containing an α-glycosidic bond and a β-glucan derivative containing a β-glycosidic bond. As a specific example of the α-glucan derivative, a pullulan derivative can be cited. The pullulan derivative is represented by the following formula (α1), for example. As a specific example of the β-glucan derivative, a laminarin derivative can be cited. The laminarin derivative is represented by the following formula (β1), for example.

[0078] [Chemistry 1]

[0079]

[0080] In each of formula (α1) and (β1), n ​​is an integer. X is independently a hydrogen atom (excluding the case where all X are hydrogen atoms) or an arbitrary substituent. X may be the same as or different from each other. A specific example of an arbitrary substituent is an acyl group. As the acyl group, the above examples can be cited.

[0081] The glucan derivative G preferably contains at least one selected from the group consisting of a pullulan derivative and a laminarin derivative, and more preferably contains a pullulan derivative. When the glucan derivative G contains a pullulan derivative, anchor failure and cohesive failure tend to be suppressed in the adhesive sheet formed by the adhesive composition. When the glucan derivative G contains both a pullulan derivative and a laminarin derivative, the weight ratio of the pullulan derivative to the laminarin derivative is not particularly limited, and is, for example, 5:95 to 99:1, 30:70 to 95:5, and further 50:50 to 90:10.

[0082] The weight average molecular weight of the glucan derivative G is not particularly limited, and is, for example, 10,000 or more, 30,000 or more, 100,000 or more, 150,000 or more, 200,000 or more, 300,000 or more, and further 400,000 or more. The weight average molecular weight of the glucan derivative G is, for example, 5 million or less, 3 million or less, 2.5 million or less, 2 million or less, 1 million or less, 800,000 or less, and further 500,000 or less. The weight average molecular weight of the glucan derivative G is preferably 150,000 to 2.5 million.

[0083] The glucan derivative G can be synthesized, for example, by introducing a substituent, particularly an acyl group, into an unsubstituted glucan having glycosidic bonds A and B. As an example, the glucan derivative G into which the acyl group is introduced can be synthesized by reacting the hydroxyl group contained in the glucan with an acylating agent. Examples of the acylating agent include acyl chlorides and acid anhydrides. The conditions for the reaction of the glucan with the acylating agent can be appropriately set according to the types of the glucan and the acylating agent.

[0084] It should be noted that the weight average molecular weight of the dextran before the introduction of the substituent is not particularly limited, and is, for example, 10,000 or more, 30,000 or more, 100,000 or more, 200,000 or more, 300,000 or more, and further 400,000 or more. The weight average molecular weight of the dextran is, for example, 1,000,000 or less, 800,000 or less, and further 500,000 or less.

[0085] The content of the glucan derivative G in the adhesive composition is not particularly limited, and may be, for example, 1 wt % or more, 10 wt % or more, 30 wt % or more, 50 wt % or more, 80 wt % or more, or 90 wt % or more.

[0086] The adhesive composition may further include additives other than the dextran derivative G. As additives, other base polymers, tackifiers, crosslinking agents, photoradical generators, free radical polymerizable compounds, solvents, viscosity modifiers, leveling agents, plasticizers, fillers, stabilizers, preservatives, antioxidants, etc. can be cited. The adhesive composition may further include a tackifier as an additive, and may further include a crosslinking agent as an additive. It should be noted that the adhesive composition may also not contain a crosslinking agent.

[0087] As other base polymers, (meth)acrylic resins and the like can be mentioned.

[0088] The tackifier is a component for improving the adhesive force of the adhesive composition and includes, for example, at least one selected from the group consisting of terpene resins, rosin resins, and petroleum resins.

[0089] Examples of the terpene resin include terpene resins, hydrogenated products of terpene resins, aromatic modified terpene resins, phenol-modified terpene resins, hydrogenated products of phenol-modified terpene resins, etc., and phenol-modified terpene resins are preferred. Examples of the terpene resin include α-pinene polymers, β-pinene polymers, dipentene polymers, etc.

[0090] Examples of rosin-based resins include disproportionated rosin, rosin esters, phenol-modified rosin, hydrogenated rosin, polymerized rosin, maleic rosin, fumaric rosin, disproportionated maleic acid-modified rosin resins, etc., preferably rosin esters and phenol-modified rosin. Examples of rosin esters include pentaerythritol ester-modified rosin resins, etc.

[0091] Examples of petroleum-based resins include aliphatic (C5) petroleum resins, aromatic (C9) petroleum resins, aliphatic / aromatic copolymer (C5 / C9) petroleum resins, their hydrogenated products, their modified products (e.g., maleic anhydride modified products), coumarone resins, coumarone indene resins, styrene-based tackifiers, and the like. Preferred are hydrogenated products, and particularly preferred are hydrogenated products of aromatic (C9) petroleum resins.

[0092] The amount of the thickener to be added is not particularly limited. As an example, the amount of the thickener to be added relative to 100 parts by weight of the glucan derivative G is, for example, 5 parts by weight or more, 10 parts by weight or more, and further 20 parts by weight or more. The amount of the thickener to be added relative to 100 parts by weight of the glucan derivative G is, for example, 150 parts by weight or less, 120 parts by weight or less, 100 parts by weight or less, 90 parts by weight or less, 70 parts by weight or less, 60 parts by weight or less, and further 40 parts by weight or less.

[0093] The crosslinking agent is preferably a crosslinking agent that can react with the hydroxyl groups remaining in the dextran derivative G. Examples of the crosslinking agent include isocyanate crosslinking agents, oxazoline crosslinking agents, carbodiimide crosslinking agents, epoxy crosslinking agents, etc. The crosslinking agent may contain a compound C containing a (meth)acryloyl group and a hydroxyl-reactive functional group. The crosslinking agent preferably contains an isocyanate crosslinking agent.

[0094] Examples of isocyanate crosslinking agents include adduct-type isocyanate crosslinking agents, isocyanurate-type isocyanate crosslinking agents, allophanate-type isocyanate crosslinking agents, etc. Examples of isocyanate crosslinking agents include hexamethylene diisocyanate (HDI)-type crosslinking agents, toluene diisocyanate (TDI)-type crosslinking agents, xylene diisocyanate (XDI)-type crosslinking agents, and hydrogenated xylene diisocyanate (H6XDI) (also known as 1,3-bis(isocyanatomethyl)cyclohexane)-type crosslinking agents.

[0095] As HDI type crosslinking agent, trimethylolpropane adduct of HDI, isocyanurate of HDI, allophanate of HDI, etc. can be cited, preferably isocyanurate of HDI. In the case of using isocyanurate of HDI, there is a tendency to suppress the situation that the components of the adhesive composition remain in the adherend. As TDI type crosslinking agent, trimethylolpropane adduct of TDI, isocyanurate of TDI, allophanate of TDI, etc. can be cited. As XDI type crosslinking agent, trimethylolpropane adduct of XDI, isocyanurate of XDI, allophanate of XDI, etc. can be cited. As H6XDI type crosslinking agent, trimethylolpropane adduct of H6XDI, isocyanurate of H6XDI, allophanate of H6XDI, etc. can be cited.

[0096] In the compound C containing a (meth)acryloyl group and a hydroxyl-reactive functional group, the (meth)acryloyl group refers to an acryloyl group and / or a methacryloyl group. As the hydroxyl-reactive functional group, an isocyanate group, an epoxy group, an alkoxysilyl group, an acid anhydride group, an acyl chloride group, etc. can be cited, preferably an isocyanate group. The number of (meth)acryloyl groups contained in the compound C can be 1 or more than 2. The number of hydroxyl-reactive functional groups contained in the compound C can be 1 or more than 2.

[0097] Compound C can react with the hydroxyl group remaining in the dextran derivative G via the hydroxyl-reactive functional group. By reacting compound C with the dextran derivative G, a (meth)acryloyl group can be introduced into the dextran derivative G. By reacting a plurality of dextran derivatives G with each other using the (meth)acryloyl group, the dextran derivative G can be cross-linked. It should be noted that in this specification, the reaction product of the dextran derivative G and compound C is sometimes referred to as dextran derivative G.

[0098] As for the compound C containing an isocyanate group as a hydroxyl-reactive functional group, there can be mentioned isocyanatoalkyl (meth)acrylates, (meth)acryloyl (poly)oxyalkylene alkyl isocyanate, etc. Specific examples of isocyanatoalkyl (meth)acrylates include isocyanatomethyl (meth)acrylates, isocyanatoethyl (meth)acrylates, isocyanatopropyl (meth)acrylates, isocyanatobutyl (meth)acrylates, etc. Specific examples of isocyanatoalkyl (meth)acrylates include isocyanatomethyl (meth)acrylates, isocyanatoethyl (meth)acrylates, isocyanatopropyl (meth)acrylates, isocyanatobutyl (meth)acrylates, etc. (meth)acryloyl (poly)oxyalkylene alkyl isocyanate includes (meth)acryloyl polyoxyethylene ethyl isocyanate, (meth)acryloyloxyethyloxyethyl isocyanate, etc.

[0099] Commercially available products can be used as the isocyanate group-containing compound C. Examples of commercially available products include Karenz AOI (manufactured by Showa Denko, 2-isocyanatoethyl acrylate), Karenz MOI (manufactured by Showa Denko, 2-isocyanatoethyl methacrylate), and Karenz MOI-EG (manufactured by Showa Denko, 2-(2-methacryloyloxyethyloxy)ethyl isocyanate).

[0100] The amount of the cross-linking agent is not particularly limited. As an example, the amount of the cross-linking agent to be added to 100 parts by weight of the glucan derivative G is, for example, 0.01 parts by weight or more, 0.1 parts by weight or more, 0.5 parts by weight or more, 1.0 parts by weight or more, 3.0 parts by weight or more, and further 5.0 parts by weight or more. The amount of the cross-linking agent to be added to 100 parts by weight of the glucan derivative G is, for example, 50 parts by weight or less, 25 parts by weight or less, 20 parts by weight or less, 15 parts by weight or less, and further 10 parts by weight or less. The amount of the cross-linking agent to be added to 100 parts by weight of the glucan derivative G may be 5.0 parts by weight or less, or 3.0 parts by weight or less, depending on the circumstances.

[0101] When the adhesive composition includes the above-mentioned compound C as a crosslinking agent, the adhesive composition preferably further includes a photoradical generator and may further include a radical polymerizable compound. A photoradical generator is a compound that generates free radicals by irradiation with light. In this specification, light includes radiation (gamma rays, X-rays, etc.), ultraviolet rays, visible rays, etc.

[0102] As the photo radical generator, benzyl ketal compounds, α-hydroxy ketone photopolymerization initiators, α-amino ketone photopolymerization initiators, acyl phosphine oxide photopolymerization initiators, oxime ester photopolymerization initiators, acridine photopolymerization initiators, titanocene photopolymerization initiators, benzophenone photopolymerization initiators, acetophenone photopolymerization initiators, aromatic ketone ester photopolymerization initiators, benzoate photopolymerization initiators, etc., preferably benzyl ketal compounds. As the photo radical generator, commercially available products can be used. As commercially available products, Omnirad184, 369, 500, 651, 819, 907, 784, 2959 (above, IGM Resins BV system), CGI-1700, -1750, -1850, CG24-61, Darocur1116, 1173 (above, BASF Co., Ltd. system) and the like can be cited.

[0103] The amount of the photoradical generator to be added is not particularly limited. As an example, the amount of the photoradical generator to be added relative to 100 parts by weight of the glucan derivative G is, for example, 0.01 parts by weight or more, 0.05 parts by weight or more, 0.075 parts by weight or more, and further 0.1 parts by weight or more. The amount of the photoradical generator to be added relative to 100 parts by weight of the glucan derivative G is, for example, 5 parts by weight or less, 1 part by weight or less, 0.5 parts by weight or less, and further 0.2 parts by weight or less.

[0104] The radical polymerizable compound is, for example, a compound having a radical polymerizable unsaturated double bond, and examples thereof include (meth)acrylic acid, (meth)acrylic acid amide, aromatic vinyl, vinyl ester, acrylonitrile, etc. (meth)acrylic acid refers to acrylic acid and / or methacrylic acid.

[0105] Examples of (meth)acrylic acid include (meth)acrylic acid monomers and (meth)acrylic acid oligomers. In (meth)acrylic acid monomers, the residue bonded to the (meth)acryloyl group does not contain a repeating unit. (Meth)acrylic acid monomers may or may not contain a functional group. Examples of (meth)acrylic acid monomers include (meth)acrylic acid alkyl esters, carboxyl group-containing (meth)acrylic acid monomers, and hydroxyl group-containing (meth)acrylic acid monomers.

[0106] Examples of the alkyl (meth)acrylate include alkyl (meth)acrylates having a linear or branched aliphatic alkyl group or an alicyclic alkyl group. Specific examples of the alkyl (meth)acrylate include methyl (meth)acrylate, ethyl (meth)acrylate, butyl (meth)acrylate, 2-ethylhexyl (meth)acrylate, nonyl (meth)acrylate, lauryl (meth)acrylate, cyclohexyl (meth)acrylate, and isobornyl (meth)acrylate.

[0107] Examples of the carboxyl group-containing (meth)acrylic acid monomer include (meth)acrylic acid, and examples of the hydroxyl group-containing (meth)acrylic acid monomer include 2-hydroxyethyl (meth)acrylate, 3-hydroxypropyl (meth)acrylate, and 4-hydroxybutyl (meth)acrylate.

[0108] In the (meth)acrylic oligomer, the residue bonded to the (meth)acryloyl group contains a repeating unit. The (meth)acrylic oligomer may contain a functional group or may not contain a functional group. Examples of the (meth)acrylic oligomer include alkoxy polyoxyalkylene glycol mono (meth)acrylate, carboxyl group-containing (meth)acrylic oligomer, hydroxyl group-containing (meth)acrylic oligomer, and the like.

[0109] Examples of the alkoxypolyoxyalkylene glycol mono(meth)acrylate include alkoxypolyoxyethylene glycol mono(meth)acrylate, particularly methoxypolyoxyethylene glycol mono(meth)acrylate, and the like.

[0110] Examples of the carboxyl group-containing (meth)acrylic oligomer include ω-carboxy-polycaprolactone mono(meth)acrylate, and examples of the hydroxyl group-containing (meth)acrylic oligomer include polyoxyalkylene glycol mono(meth)acrylate.

[0111] As the (meth)acrylic oligomer, commercially available products may be used, such as BlemmerAME400 (manufactured by NOF Corporation, methoxy polyethylene glycol-acrylate), Aronix M-5300 (manufactured by Toagosei Corporation, ω-carboxy-polycaprolactone (n (polymerization degree)≈2) monoacrylate), and the like.

[0112] The amount of the radical polymerizable compound is not particularly limited. As an example, the amount of the radical polymerizable compound to be added to 100 parts by weight of the dextran derivative G is, for example, 0.001 parts by weight or more, 0.01 parts by weight or more, 0.1 parts by weight or more, 1 part by weight or more, or further 3 parts by weight or more. The amount of the radical polymerizable compound to be added to 100 parts by weight of the dextran derivative G is, for example, 100 parts by weight or less, 10 parts by weight or less, or further 7 parts by weight or less.

[0113] The solvent may be an organic solvent, and may be water. The organic solvent may be low polar or high polar. As low polar organic solvents, aromatic compounds, alicyclic compounds, saturated chain hydrocarbon compounds, etc. may be mentioned. As aromatic compounds, toluene, etc. may be mentioned. As alicyclic compounds, cyclohexane, methylcyclohexane, etc. may be mentioned. As saturated chain hydrocarbon compounds, pentane, hexane, heptane, etc. may be mentioned.

[0114] Examples of highly polar organic solvents include ketones, esters, and alcohols. Examples of ketones include methyl ethyl ketone, esters include ethyl acetate, and alcohols include methanol and ethanol.

[0115] When the adhesive composition contains a solvent, the solid content concentration in the adhesive composition is, for example, 1 wt % or more, or 10 wt % or more, or 50 wt % or less, or 40 wt % or less.

[0116] (Embodiments of Adhesive Sheet)

[0117] An example of the pressure-sensitive adhesive sheet 1 of the present embodiment is shown in Figure 1 The pressure-sensitive adhesive sheet 1 is formed from the pressure-sensitive adhesive composition described above. The thickness of the pressure-sensitive adhesive sheet 1 is not particularly limited, and is, for example, 1 μm to 1000 μm.

[0118] The adhesive sheet 1 can be produced, for example, by the following method. First, an adhesive composition is applied to a substrate sheet to obtain a coating film. As the substrate sheet, the examples described later about the laminate can be used. Then, the adhesive sheet 1 can be obtained by drying the coating film. The drying of the coating film can be performed, for example, by heating the coating film. The heating temperature of the coating film is not particularly limited, for example, it is above 30°C, and can be above 100°C. The heating time of the coating film is not particularly limited, for example, it is above 5 minutes, and can be above 30 minutes. In the case where the adhesive composition contains a photoradical generator, the coating film can be irradiated with light when or after the coating film is dried.

[0119] According to the research of the inventors, the peeling force of the adhesive sheet 1 can be easily increased by using an adhesive composition containing a glucan derivative G having glycosidic bonds A and B with different bonding modes. As an example, the peeling force F of the adhesive sheet 1 measured according to the test described later is, for example, 0.2N / 20mm or more, and can be 0.3N / 20mm or more, 0.5N / 20mm or more, 0.8N / 20mm or more, 1N / 20mm or more, 2N / 20mm or more, 3N / 20mm or more, 4N / 20mm or more, 5N / 20mm or more, 6N / 20mm or more, and further 7N / 20mm or more. The upper limit of the peeling force F of the adhesive sheet 1 is not particularly limited, for example, 20N / 20mm.

[0120] The peeling force F of the adhesive sheet 1 can be measured by the following method: Figure 2 ). First, a laminate of an adhesive sheet 1 and a substrate sheet 20 is prepared. As the substrate sheet 20, for example, Lumirror S-10 (polyester film, thickness 25 μm) manufactured by Toray is used. In the laminate, the thickness of the adhesive sheet 1 is adjusted to 50 μm, for example. Next, the laminate is cut into a width of 20 mm and a length of 70 mm to prepare a test piece 25.

[0121] Next, under the environment of 23°C and 50% RH, the test piece 25 is overlapped with the stainless steel test plate 21 by means of the adhesive sheet 1, and a 2 kg roller is reciprocated once to press them together. As the stainless steel test plate 21, for example, a SUS304BA plate is used. After being left in this state for 30 minutes, as shown in FIG. Figure 2 As shown, they are mounted in a tensile test apparatus. Specifically, one end of the stainless steel test plate 21 is fixed to the lower chuck 31 of the tensile test apparatus, and the end of the test piece 25 on the lower chuck 31 side is folded back 180° and fixed to the upper chuck 30 of the tensile test apparatus. Next, the test piece 25 is peeled off from the stainless steel test plate 21 at a peeling speed of 300 mm / min and a peeling angle of 180°, and the average value of the peeling force at this time is determined as the peeling force F of the adhesive sheet 1.

[0122] (Embodiment of Laminated Body)

[0123] An example of the laminate of this embodiment is shown in Figure 3 . Figure 3 The laminate 10 includes an adhesive sheet 1 and a substrate sheet 2, and may further include a release liner 3. In the laminate 10, the adhesive sheet 1 is, for example, disposed between the substrate sheet 2 and the release liner 3, and is directly in contact with each of the substrate sheet 2 and the release liner 3. The laminate 10 is typically an adhesive tape. The laminate 10 can be used by peeling off the release liner 3.

[0124] The substrate sheet 2 is a sheet made of a resin such as polyester. The surface of the substrate sheet 2 in contact with the pressure-sensitive adhesive sheet 1 is subjected to a release treatment and can function as a release liner. The thickness of the substrate sheet 2 is not particularly limited, and is, for example, 0.5 μm to 900 μm.

[0125] The release liner 3 is, for example, a sheet having a release-treated surface in contact with the pressure-sensitive adhesive sheet 1. Examples of the material of the release liner 3 include resins such as polyester. The thickness of the release liner 3 is not particularly limited, and is, for example, 0.5 μm to 900 μm.

[0126] Modification examples of the laminate of this embodiment are shown in Figure 4 . Figure 4 The laminate 11 includes two adhesive sheets 1 and two release liners 3. In addition to the above, the structure of the laminate 11 is the same as that of Figure 3 The structure of the stacked body 10 is the same.

[0127] Specifically, the laminate 11 has a laminate structure in which a release liner 3a, an adhesive sheet 1a, a substrate sheet 2, an adhesive sheet 1b, and a release liner 3b are laminated in this order. The laminate 11 is typically a double-sided adhesive tape. The laminate 11 can be used by peeling off the release liners 3a and 3b.

[0128] The above-mentioned laminated bodies 10 and 11 can be distributed and stored as a rolled body obtained by winding a strip-shaped laminated body, or as a single-sheet laminated body, for example.

[0129] Example

[0130] Hereinafter, the present invention will be described in further detail based on Examples and Comparative Examples, but the present invention is not limited thereto.

[0131] [Pullulan derivative 1]

[0132] First, in a reaction vessel equipped with a condenser, a nitrogen inlet tube, a thermometer and a stirrer, 10 g of pullulan (pullulan manufactured by Hayashihara Co., Ltd.) and 1000 mL of dehydrated pyridine (manufactured by FUJIFILM Wako Chemicals Corporation) were added. Pullulan has an α-1,6-glycosidic bond as a glycosidic bond A and an α-1,4-glycosidic bond as a glycosidic bond B. The ratio P1 of the number of glycosidic bonds A to the number of all glycosidic bonds contained in pullulan is 33%. The weight average molecular weight of pullulan is 500,000.

[0133] Next, the obtained mixed solution was heated to 90°C and stirred for 0.5 hours under a nitrogen atmosphere. Next, 100 mL of myristoyl chloride (manufactured by FUJIFILM Wako Chemicals Corporation) was added to the mixed solution, and stirred at 90°C for 1.5 hours. Thus, the reaction between pullulan and myristoyl chloride proceeded.

[0134] Next, 2000 mL of methanol was added to the reaction solution and cooled to room temperature. Next, the solid matter in the reaction solution was taken out and dissolved in 600 mL of toluene to obtain a toluene solution. Next, the obtained toluene solution was injected into 2000 mL of stirred methanol to precipitate the solid matter. Repeat this reprecipitation treatment 3 times. Next, the solid matter obtained by the reprecipitation treatment was dried under reduced pressure at 60°C for 4 hours to obtain pullulan derivative 1. Pullulan derivative 1 has a structure in which a myristoyl group (acyl group with 14 carbon atoms) is introduced into pullulan. In pullulan derivative 1, the degree of substitution (DS value) of the acyl group is 2.6.

[0135] [Pullulan derivative 2]

[0136] Pullulan derivative 2 was synthesized in the same manner as pullulan derivative 1 except that 90 mL of lauroyl chloride was used instead of myristoyl chloride. Pullulan derivative 2 had a structure in which a lauroyl group (acyl group having 12 carbon atoms) was introduced into pullulan. In pullulan derivative 2, the DS value of the acyl group was 2.6.

[0137] [Pullulan derivative 3]

[0138] Pullulan derivative 3 was synthesized in the same manner as in pullulan derivative 2 except that the amount of lauroyl chloride used was changed so that the DS value of the lauroyl group (acyl group having 12 carbon atoms) would be 2.4.

[0139] [Pullulan derivative 4]

[0140] Pullulan derivative 4 was synthesized in the same manner as pullulan derivative 1 except that 65 mL of octanoyl chloride was used instead of myristoyl chloride. Pullulan derivative 4 has a structure in which an octanoyl group (acyl group having 8 carbon atoms) is introduced into pullulan. In pullulan derivative 4, the DS value of the acyl group is 3.0.

[0141] [Pullulan derivative 5]

[0142] Pullulan derivative 5 was synthesized in the same manner as pullulan derivative 1 except that 115 mL of palmitoyl chloride was used instead of myristoyl chloride. Pullulan derivative 5 has a structure in which a palmitoyl group (acyl group having 16 carbon atoms) is introduced into pullulan. In pullulan derivative 5, the DS value of the acyl group is 3.0.

[0143] [Laminaria polysaccharide derivative 1]

[0144] First, 10 g of laminarin (laminarin manufactured by Nacalai Tesque Co., Ltd.) and 1000 mL of dehydrated pyridine (manufactured by FUJIFILM Wako Chemicals Corporation) were added to a reaction vessel equipped with a condenser, a nitrogen inlet tube, a thermometer, and a stirrer. Laminarin has a β-1,6-glycosidic bond as a glycosidic bond A and a β-1,3-glycosidic bond as a glycosidic bond B. The ratio P1 of the number of glycosidic bonds A to the number of all glycosidic bonds contained in laminarin is 25%. The weight average molecular weight of laminarin is 30,000 to 40,000.

[0145] Next, the obtained mixed solution was heated to 90° C. and stirred for 0.5 hours under a nitrogen atmosphere. Next, 90 mL of lauroyl chloride was added to the mixed solution, and the mixture was stirred at 90° C. for 1.5 hours. Thus, the reaction between laminarin and lauroyl chloride proceeded.

[0146] Next, 2000 mL of methanol was added to the reaction solution, and the mixture was cooled to room temperature. Next, the solid matter in the reaction solution was taken out and dissolved in 600 mL of toluene to obtain a toluene solution. Next, the obtained toluene solution was injected into 2000 mL of stirred methanol to precipitate the solid matter. This reprecipitation treatment was repeated 3 times. Next, the solid matter obtained by the reprecipitation treatment was dried under reduced pressure at 60° C. for 4 hours to obtain laminarin derivative 1. Laminarin derivative 1 has a structure in which a lauroyl group (acyl group having 12 carbon atoms) is introduced into laminarin. In laminarin derivative 1, the DS value of the acyl group is 3.0.

[0147] [Laminaria polysaccharide derivative 2]

[0148] Laminarin derivative 2 was synthesized in the same manner as laminarin derivative 1 except that 100 mL of myristoyl chloride was used instead of lauroyl chloride. Laminarin derivative 2 had a structure in which a myristoyl group (acyl group having 14 carbon atoms) was introduced into laminarin. In laminarin derivative 2, the DS value of the acyl group was 3.0.

[0149] (Example 1)

[0150] First, a pullulan derivative 1 is dissolved in toluene to prepare an adhesive composition having a solid content concentration of 20 wt%. The adhesive composition is applied to a substrate sheet to prepare a coating film. As a substrate sheet, Lumirror S-10 (polyester film, thickness 25 μm) manufactured by Toray is used. The adhesive composition is applied using an applicator (manufactured by Tester Industries). Next, the coating film is dried at 60° C. for 5 minutes to obtain the adhesive sheet of Example 1. The thickness of the adhesive sheet is 50 μm.

[0151] (Examples 2 to 4)

[0152] Except that the type of the glucan derivative was changed as shown in Table 1, the same method as in Example 1 was carried out to obtain PSA sheets of Examples 2 to 4.

[0153] (Example 5)

[0154] First, a pullulan derivative 1 is dissolved in toluene to prepare a toluene solution S1 having a solid content concentration of 20 wt%. Next, a phenol-modified terpene resin (YS Polyster T-130 manufactured by YASUHARA CHEMICAL CO., LTD.) as a tackifier is dissolved in toluene to prepare a toluene solution S2 having a solid content concentration of 20 wt%. The toluene solutions S1 and S2 are mixed and stirred to prepare an adhesive composition. The toluene solutions S1 and S2 are mixed in such a manner that the blending amount of the aromatic modified terpene resin is 30 parts by weight relative to 100 parts by weight of the pullulan derivative 1.

[0155] Next, the obtained adhesive composition was applied to a substrate sheet to prepare a coating film. As a substrate sheet, Lumirror S-10 (polyester film, thickness 25 μm) manufactured by Toray was used. The adhesive composition was applied using an applicator (manufactured by Tester Industries). Next, the coating film was dried at 60° C. for 5 minutes to obtain an adhesive sheet of Example 5. The thickness of the adhesive sheet was 50 μm.

[0156] (Examples 6 to 8)

[0157] Except that the type of the glucan derivative was changed as shown in Table 1, the same method as in Example 5 was carried out to obtain PSA sheets of Examples 6 to 8.

[0158] (Example 9)

[0159] First, the pullulan derivative 1 was dissolved in toluene to prepare a toluene solution having a solid content concentration of 20 wt%. Next, an isocyanate crosslinking agent (TAKENATE D-101A (trimethylolpropane adduct of toluene diisocyanate) manufactured by Mitsui Chemicals, Inc.) was blended into the toluene solution to prepare an adhesive composition. The blending amount of the isocyanate crosslinking agent was 3.0 parts by weight relative to 100 parts by weight of the pullulan derivative 1.

[0160] Next, the obtained adhesive composition was applied to a substrate sheet to prepare a coating film. As a substrate sheet, Lumirror S-10 (polyester film, thickness 25 μm) manufactured by Toray was used. The adhesive composition was applied using an applicator (manufactured by Tester Industries). Next, the coating film was treated at 60°C for 5 minutes, at 120°C for 3 minutes, and at 50°C for 3 days to obtain the adhesive sheet of Example 9. The thickness of the adhesive sheet was 50 μm.

[0161] (Examples 10-11)

[0162] Except that the type of the glucan derivative was changed as shown in Table 2, the same method as in Example 9 was carried out to obtain PSA sheets of Examples 10 to 11.

[0163] (Example 12)

[0164] A PSA sheet of Example 12 was obtained in the same manner as in Example 5, except that pullulan derivative 4 was used as the glucan derivative, a phenol-modified terpene resin (YS Polyster T-80 manufactured by YASUHARA CHEMICAL CO., LTD.) was used as the thickener, and the amount of the thickener blended per 100 parts by weight of the glucan derivative was changed as shown in Table 2.

[0165] (Example 13)

[0166] A PSA sheet of Example 13 was obtained in the same manner as in Example 5 except that pullulan derivative 5 was used as the glucan derivative and the amount of the thickener blended per 100 parts by weight of the glucan derivative was changed as shown in Table 2.

[0167] (Examples 14 to 17)

[0168] PSA sheets of Examples 14 to 17 were obtained by the same method as in Example 5, except that pullulan derivative 3 was used as the glucan derivative, rosin-based resin (Pinecrystal KE100 manufactured by Arakawa Chemical Industries) was used as the tackifier, and the amount of the tackifier blended per 100 parts by weight of the glucan derivative was changed as shown in Table 2.

[0169] (Examples 18 to 21)

[0170] As the glucan derivative, a mixture of pullulan derivative 3 and laminarin derivative 1 at the weight ratio shown in Table 3 was used, a rosin-based resin (Pinecrystal KE100 manufactured by Arakawa Chemical Industries) was used as a tackifier, and the amount of the tackifier blended per 100 parts by weight of the glucan derivative was changed as shown in Table 3. PSA sheets of Examples 18 to 21 were obtained in the same manner as in Example 5.

[0171] (Example 22)

[0172] A PSA sheet of Example 22 was obtained in the same manner as in Example 1 except that the pullulan derivative 3 and the laminarin derivative 1 were mixed at the weight ratio shown in Table 4 as the glucan derivative.

[0173] (Comparative Example 1)

[0174] First, pullulan (pululan manufactured by Hayashihara Co., Ltd.) is dissolved in water to prepare an adhesive composition having a solid content concentration of 20 wt%. The adhesive composition is applied to a substrate sheet to prepare a coating film. As a substrate sheet, Lumirror S-10 (polyester film, thickness 25 μm) manufactured by Toray is used. The adhesive composition is applied with an applicator (manufactured by Tester Industries). Next, the coating film is dried at 90° C. for 15 minutes to obtain an adhesive sheet of Comparative Example 1. The thickness of the adhesive sheet is 50 μm.

[0175] (Comparative Example 2)

[0176] A PSA sheet of Comparative Example 2 was obtained in the same manner as in Comparative Example 1 except that laminarin (laminarin manufactured by Nacalai Tesque Co., Ltd.) was used instead of pullulan.

[0177] [Peel force F]

[0178] For the adhesive sheets of the embodiments and comparative examples, the peeling force F was determined by the above method. In the determination of the peeling force F, a precision universal testing machine Autograph AG-IS manufactured by Shimadzu Corporation was used as a tensile test device. It should be noted that for Examples 3 and 4, peeling (anchor failure) between the adhesive sheet and the substrate sheet was observed in the determination of the peeling force F. For Examples 7, 8, 18 and 19, cohesive failure of the adhesive sheet was observed in the determination of the peeling force F. For Example 11, peeling (anchor failure) between the adhesive sheet and the substrate sheet and cohesive failure of the adhesive sheet were observed in the determination of the peeling force F.

[0179] [Table 1]

[0180]

[0181] [Table 2]

[0182]

[0183] [Table 3]

[0184]

[0185] [Table 4]

[0186]

[0187] (*1) Weight average molecular weight of dextran before acyl group introduction

[0188] (*2)) Ratio of the number of glycosidic bonds A to the total number of glycosidic bonds

[0189] As can be seen from Tables 1 to 4, the peeling force F of the PSA sheets of Examples formed from the PSA composition containing the glucan derivative G having glycosidic bonds A and B is higher than that of the Comparative Examples. It should be noted that, according to the study by the present inventors, the peeling force F of the PSA sheets of Examples tends to be greater than the peeling force F of the PSA sheets formed from the PSA composition containing the glucan derivative having a single type of glycosidic bond (e.g., paramylon derivative).

[0190] Industrial Applicability

[0191] The adhesive composition of this embodiment can be used for adhesive tapes.

Claims

1. An adhesive composition comprising: a glucan derivative having a glycosidic bond A and a glycosidic bond B having a bonding mode different from that of the glycosidic bond A.

2. The adhesive composition according to claim 1, wherein The glycosidic bond A is a 1,6-glycosidic bond.

3. The adhesive composition according to claim 1, wherein The glycosidic bond B is at least one selected from the group consisting of a 1,3-glycosidic bond and a 1,4-glycosidic bond.

4. The adhesive composition according to claim 1, wherein The ratio of the number of the glycosidic bonds A to the number of all glycosidic bonds contained in the glucan derivative is 10% to 50%.

5. The adhesive composition according to claim 1, wherein The dextran derivative comprises an acyl group.

6. The adhesive composition according to claim 5, wherein The acyl group has 8 to 16 carbon atoms.

7. The adhesive composition according to claim 5, wherein The acyl group is represented by the following formula (1): RCO-(1) In the formula (1), R is a hydrocarbon group.

8. The adhesive composition according to claim 5, wherein In the dextran derivative, the degree of substitution (DS value) of the acyl group is greater than 2.

0.

9. The adhesive composition according to claim 1, wherein The glucan derivative includes at least one selected from the group consisting of pullulan derivatives and laminarin derivatives.

10. The adhesive composition according to claim 1, wherein The weight average molecular weight of the dextran derivative is 5 million or less. The adhesive composition according to claim 1 , further comprising a tackifier.

12. The adhesive composition according to claim 11, wherein The tackifier includes at least one selected from the group consisting of terpene resins, rosin resins, and petroleum resins.

13. The adhesive composition according to claim 1, further comprising a crosslinking agent.

14. The adhesive composition according to claim 13, wherein The cross-linking agent includes an isocyanate-based cross-linking agent. 15 . A pressure-sensitive adhesive sheet comprising the pressure-sensitive adhesive composition according to claim 1 . 16 . A laminate comprising the pressure-sensitive adhesive sheet according to claim 15 and a substrate sheet.

17. A dextran derivative having: Glycosidic bond A, A glycosidic bond B having a bonding mode different from that of the glycosidic bond A, and An acyl group having 8 to 16 carbon atoms.

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