Adhesive composition, adhesive sheet, laminate, and method for producing beta-1, 3-glucan derivative

Abstract

Provided is an adhesive composition suitable for forming an adhesive sheet having a smooth surface. The adhesive composition according to the present invention comprises a beta-1, 3-glucan derivative G. In the adhesive composition, tan [delta] at 200 DEG C as determined by the following test is 0.7 or more. Test: using the adhesive composition to produce a disc-shaped sample for evaluation. And performing dynamic viscoelasticity measurement on the sample for evaluation to determine tan delta at 200 DEG C.

Description

Technical Field

[0001] The present invention relates to an adhesive composition, an adhesive sheet, a laminate, and a method for producing a β-1,3-glucan derivative. Background Art

[0002] In recent years, bioplastics using renewable resources have been studied from the perspective of reducing environmental load. As renewable resources, for example, polysaccharides derived from organisms or plants are known. As specific examples of such polysaccharides, β-glucan containing β-glucose (specifically, β-D-glucose) as a constituent sugar can be cited.

[0003] β-glucan is classified into β-1,4-glucan or β-1,3-glucan, etc., according to the bonding positions of β-glucose. As a specific example of β-1,4-glucan, cellulose can be cited, and as a specific example of β-1,3-glucan, paramylon can be cited. Paramylon is synthesized by photosynthesis of microalgae such as Euglena. Microalgae have the following advantages: they can not only be easily cultured, but also can absorb a large amount of carbon dioxide during their culture process.

[0004] In order to effectively utilize β-1,3-glucans such as paramylon, studies have been conducted on introducing substituents into β-1,3-glucans to synthesize β-1,3-glucan derivatives. As an example, Patent Document 1 discloses the use of acyl-introduced β-1,3-glucan derivatives for adhesives and the like.

[0005] Prior art literature

[0006] Patent Literature

[0007] Patent Document 1: Japanese Patent No. 6890316 Summary of the invention

[0008] Problem that the invention aims to solve

[0009] According to the research of the present inventors, when a β-1,3-glucan derivative is synthesized by the method disclosed in Patent Document 1 to prepare an adhesive composition containing the β-1,3-glucan derivative, there is a tendency for the surface of the adhesive sheet formed from the adhesive composition to be uneven. If the surface of the adhesive sheet is uneven, the thickness of the adhesive sheet will be uneven, and thus, uneven adhesive force may also be generated.

[0010] Therefore, an object of the present invention is to provide a PSA composition suitable for forming a PSA sheet having a smooth surface.

[0011] Solutions for solving problems

[0012] The present inventors have conducted intensive studies and have newly discovered that the tan δ value of an evaluation sample prepared from a PSA composition tends to be correlated with the surface state of a PSA sheet. Based on this finding, the present inventors have conducted studies and have completed the present invention.

[0013] The present invention provides an adhesive composition.

[0014] It contains a β-1,3-glucan derivative, and

[0015] The adhesive composition has a tan δ of 0.7 or more at 200°C as determined by the following test;

[0016] Test: A disc-shaped evaluation sample was prepared using the above-mentioned adhesive composition; the dynamic viscoelasticity of the evaluation sample was measured to determine tan δ at 200°C.

[0017] Furthermore, the present invention provides an adhesive sheet,

[0018] It is formed from the above-mentioned adhesive composition.

[0019] Furthermore, the present invention provides a laminated body,

[0020] It has:

[0021] The above adhesive sheet; and

[0022] Substrate sheet.

[0023] Furthermore, the present invention provides a method for producing a β-1,3-glucan derivative, comprising:

[0024] In a state where β-1,3-glucan is dissolved in solvent A, substituent a is introduced into the β-1,3-glucan to synthesize an intermediate product into which the substituent a is introduced; and

[0025] The β-1,3-glucan derivative is synthesized by introducing a substituent b into the intermediate product while the intermediate product is dissolved in a solvent B different from the solvent A.

[0026] Effects of the Invention

[0027] According to the present invention, a PSA composition suitable for forming a PSA sheet having a smooth surface can be provided. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] Figure 1 This is a cross-sectional view schematically showing a pressure-sensitive adhesive sheet according to one embodiment of the present invention.

[0029] Figure 2 It is a figure for demonstrating the measurement method of the peeling force of a PSA sheet.

[0030] Figure 3 This is a cross-sectional view schematically showing a laminated body according to one embodiment of the present invention.

[0031] Figure 4 It is a cross-sectional view schematically showing a modified example of the stacked body. DETAILED DESCRIPTION

[0032] The first aspect of the adhesive composition of the present invention comprises a β-1,3-glucan derivative, and

[0033] The adhesive composition has a tan δ at 200° C. of 0.7 or more as determined by the following test.

[0034] Test: A disc-shaped evaluation sample was prepared using the above-mentioned adhesive composition, and the dynamic viscoelasticity of the evaluation sample was measured to determine tan δ at 200°C.

[0035] In a second aspect of the present invention, for example, in the adhesive composition of the first aspect, the tan δ is 4.1 or less.

[0036] In a third aspect of the present invention, for example, in the PSA composition of the first or second aspect, the β-1,3-glucan derivative contains an acyl group.

[0037] In a fourth aspect of the present invention, for example, in the PSA composition of the third aspect, in the β-1,3-glucan derivative, the degree of substitution (DS value) of the acyl group is 2.6 or more and less than 3.0.

[0038] In a fifth aspect of the present invention, for example, in the adhesive composition of the third or fourth aspect, the acyl group is represented by the following formula (1);

[0039] RCO-(1)

[0040] In the above formula (1), R is a hydrocarbon group.

[0041] In a sixth aspect of the present invention, for example, in the adhesive composition of the fifth aspect, the hydrocarbon group has 7 to 15 carbon atoms.

[0042] In a seventh aspect of the present invention, for example, the pressure-sensitive adhesive composition according to any one of the first to sixth aspects further includes a tackifier.

[0043] In an eighth aspect of the present invention, for example, in the adhesive composition of the seventh aspect, the tackifier includes at least one selected from the group consisting of terpene resins, rosin resins, and petroleum resins.

[0044] In a ninth aspect of the present invention, for example, the pressure-sensitive adhesive composition according to any one of the first to eighth aspects further includes a cross-linking agent.

[0045] In a tenth aspect of the present invention, for example, in the pressure-sensitive adhesive composition of the ninth aspect, the crosslinking agent includes an isocyanate crosslinking agent.

[0046] The pressure-sensitive adhesive sheet according to the eleventh aspect of the present invention is formed from the pressure-sensitive adhesive composition according to any one of the first to tenth aspects.

[0047] A laminated body according to a twelfth aspect of the present invention includes:

[0048] Adhesive sheet of the eleventh aspect

[0049] and a substrate sheet.

[0050] The production method according to the 13th aspect of the present invention is a method for producing a β-1,3-glucan derivative, comprising:

[0051] In a state where β-1,3-glucan is dissolved in solvent A, substituent a is introduced into the β-1,3-glucan to synthesize an intermediate product into which the substituent a is introduced; and

[0052] The β-1,3-glucan derivative is synthesized by introducing a substituent b into the intermediate product while the intermediate product is dissolved in a solvent B different from the solvent A.

[0053] In a fourteenth aspect of the present invention, for example, in the production method of the thirteenth aspect, the substituent a and the substituent b are the same as each other.

[0054] In a fifteenth aspect of the present invention, for example, in the production method of the thirteenth or fourteenth aspect, the solvent A contains dimethylacetamide.

[0055] In a sixteenth aspect of the present invention, for example, in the production method according to any one of the thirteenth to fifteenth aspects, the solvent B contains at least one selected from the group consisting of toluene, cyclohexane, and tetrahydrofuran.

[0056] Hereinafter, the present invention will be described in detail, but the following description is not intended to limit the present invention to specific embodiments.

[0057] (Embodiment of Adhesive Composition)

[0058] The pressure-sensitive adhesive composition of the present embodiment contains the β-1,3-glucan derivative G. The pressure-sensitive adhesive composition has a tan δ (loss tangent) at 200° C. determined by the following test and is 0.7 or more.

[0059] Test: A disc-shaped evaluation sample was prepared using the adhesive composition. The evaluation sample was subjected to dynamic viscoelasticity measurement to determine tan δ at 200°C.

[0060] In the above test, the diameter of the evaluation sample, for example, the bottom surface is 7.9 mm, and the thickness is about 0.7 mm. The evaluation sample can be made, for example, by the following method. First, a plurality of adhesive sheets are made from the adhesive composition. The production of the adhesive sheet can be carried out by the following method. Then, a plurality of adhesive sheets are stacked, and the obtained laminate is punched into a disc shape. Thus, the evaluation sample can be made.

[0061] The dynamic viscoelasticity measurement can be performed by the following method. First, the evaluation sample is clamped between parallel plates and set in a dynamic viscoelasticity measurement device. As a dynamic viscoelasticity measurement device, for example, ARES-G2 manufactured by TA Instruments can be used. Using the dynamic viscoelasticity measurement device, the dynamic viscoelasticity measurement is performed under the following conditions.

[0062] (Measurement conditions)

[0063] Frequency: 1Hz

[0064] Deformation mode: Twist

[0065] Measuring temperature: -60℃~200℃

[0066] Heating rate: 5℃ / min

[0067] The storage modulus G' (MPa) and the loss modulus G" (MPa) at 200°C were determined from the results of the dynamic viscoelasticity measurement. The ratio G" / G' of the loss modulus G" to the storage modulus G' can be regarded as tan δ at 200°C.

[0068] In the adhesive composition having a tanδ of 0.7 or more at 200°C obtained by the above test, there is a tendency that there is less unnecessary gel. According to the research of the inventors, when an adhesive sheet is made from such an adhesive composition, there is a tendency to suppress the generation of unevenness on the surface of the adhesive sheet. By suppressing the generation of unevenness, the unevenness of the thickness of the adhesive sheet can be suppressed, and thus, there is a tendency to suppress the unevenness of the adhesive force. Furthermore, in the adhesive sheet formed by the adhesive composition, the generation of fish-eye-shaped foreign matter (fish eyes) can also be suppressed. By suppressing the adhesive sheet with fish eyes, when the adhesive sheet is peeled off from the adherend, it is not easy to cause residual glue or cohesive failure.

[0069] The tanδ at 200°C is, for example, 0.8 or more, and may be 1.0 or more, 1.2 or more, 1.4 or more, 1.6 or more, 1.8 or more, 2.0 or more, 2.2 or more, 2.4 or more, 2.6 or more, 2.8 or more, 3.0 or more, 3.5 or more, and further 4.0 or more. The upper limit of tanδ at 200°C is not particularly limited. The tanδ at 200°C is, for example, 10 or less, and may be 8.0 or less, 5.0 or less, 4.5 or less, and further 4.1 or less.

[0070] [β-1,3-Glucan derivatives]

[0071] The β-1,3-glucan derivative G functions as a base polymer in an adhesive composition, for example. The β-1,3-glucan derivative G has a glucose unit U sidically bonded to β-1,3-glucose. The β-1,3-glucan derivative G contains the glucose unit U as a main component, and is preferably substantially composed of only the glucose unit U. In the present specification, the "main component" refers to the structural unit with the largest content on a weight basis among all the structural units constituting the β-1,3-glucan derivative G. "Substantially composed of only to" means excluding other components that would change the essential characteristics of the structural unit mentioned, and means, for example, that more than 95wt%, and further more than 99wt% is composed of the structural unit. However, the β-1,3-glucan derivative G may also contain other structural units other than the glucose unit U.

[0072] Examples of the glucose unit U include a glucose unit U1 that is not connected to any other glucosidic bond except for the β-1,3-glucosidic bond, and a glucose unit U2 that is connected to both the β-1,3-glucosidic bond and other glucosidic bonds. Examples of other glucosidic bonds connected to the glucose unit U2 include a β-1,6-glucosidic bond.

[0073] In the β-1,3-glucan derivative G, the number of glucosidic bonds connected to one glucose unit U is generally 1 to 3. The β-1,3-glucan derivative G containing glucose units U connected to three glucosidic bonds can be said to have a branched structure. On the other hand, the β-1,3-glucan derivative G consisting only of glucose units U connected to one glucosidic bond and glucose units U connected to two glucosidic bonds can be said to have a linear structure without a branched structure.

[0074] 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 β-1,3-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 a hydroxyl group.

[0075] The carbon number of the acyl group of the β-1,3-glucan derivative G is, for example, 4 or more, 6 or more, 7 or more, 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, 19 or less, 18 or less, 17 or less, 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.

[0076] The acyl group contained in the β-1,3-glucan derivative G is represented by, for example, the following formula (1).

[0077] RCO-(1)

[0078] 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, 3 or more, and may be 5 or more, 6 or more, 7 or more, 8 or more, 9 or more, 10 or more, 11 or more, and further 12 or more. The number of carbon atoms in the hydrocarbon group is, for example, 18 or less, and may be 17 or less, 16 or less, 15 or less, 14 or less, and further 13 or less. The number of carbon atoms in the hydrocarbon group is preferably 7 to 15.

[0079] Examples of the hydrocarbon group include aliphatic hydrocarbon groups, alicyclic hydrocarbon groups, and aromatic hydrocarbon groups, preferably aliphatic hydrocarbon groups. 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, preferably saturated aliphatic hydrocarbon groups (alkyl groups). Examples of the unsaturated aliphatic hydrocarbon group include alkenyl groups.

[0080] Examples of the alkyl group include propyl, butyl, pentyl, hexyl, heptyl, octyl, nonyl, decyl, undecyl, dodecyl, tridecyl, tetradecyl, pentadecyl, hexadecyl, heptadecyl, and octadecyl. Examples of the alkenyl group include heptadecenyl.

[0081] Specific examples of the acyl group represented by formula (1) include butyryl, valeryl, hexanoyl, heptanoyl, octanoyl, nonanoyl, decanoyl, lauroyl, myristoyl, palmitoyl, stearoyl, oleoyl, nonadecanoyl, etc. The acyl group is preferably octanoyl, nonanoyl, decanoyl, lauroyl, myristoyl, palmitoyl, etc.

[0082] In the β-1,3-glucan derivative G, the degree of substitution (DS value) of the acyl group is, for example, greater than 2.5, and may also be greater than 2.6, greater than 2.7, greater than 2.8, and further greater than 2.9. When the DS value of the acyl group is as large as this, in the β-1,3-glucan derivative G, there is a tendency that the interaction between the molecular chains is weakened, and the adhesive force of the adhesive composition increases. The DS value of the acyl group is, for example, less than 3.0, and may be less than 2.9 or less than 2.8 depending on the circumstances. In this case, when the adhesive sheet is formed from the adhesive composition, the hydroxyl group remaining in the β-1,3-glucan derivative G can react with the following cross-linking agent. The DS value of the acyl group is preferably greater than 2.6 and less than 3.0.

[0083] It should be noted that the DS value specifically refers to the number of acyl groups contained in the β-1,3-glucan derivative G relative to one glucose unit. When the DS value is 3, it can be said that the β-1,3-glucan derivative G has a structure in which acyl groups are introduced into most of the hydroxyl groups contained in the unsubstituted glucose unit. The DS value can be obtained by performing nuclear magnetic resonance spectroscopy analysis on the β-1,3-glucan derivative G ( 1 Specifically, the β-1,3-glucan derivative G was subjected to 1 H-NMR, obtain an NMR spectrum. From the obtained NMR spectrum, the peaks derived from hydrogen atoms directly bonded to carbon atoms at positions 1 to 6 in the glucose unit of the β-1,3-glucan derivative G and the peaks derived from acyl groups are determined. Based on the integrated values ​​of these peaks, the DS value can be determined.

[0084] The β-1,3-glucan derivative G is preferably a paramylon derivative. The paramylon derivative is represented by, for example, the following formula (2).

[0085]

[0086] In formula (2), 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-mentioned acyl groups can be cited.

[0087] The β-1,3-glucan derivative G is not limited to a paramylon derivative. Other examples of the β-1,3-glucan derivative G include a curdlan derivative, a laminarin derivative, a schizophyllan derivative, a pachyman derivative, and a lentinan derivative.

[0088] The weight average molecular weight of the β-1,3-glucan derivative G 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, or 400,000 or more. The weight average molecular weight of the β-1,3-glucan derivative G is, for example, 1,000,000 or less, 800,000 or less, or 500,000 or less.

[0089] The content of the β-1,3-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. The adhesive composition may also be substantially composed of the β-1,3-glucan derivative G alone.

[0090] The method for producing the β-1,3-glucan derivative G includes, for example:

[0091] In a state where β-1,3-glucan is dissolved in solvent A, substituent a is introduced into β-1,3-glucan to synthesize an intermediate product into which substituent a is introduced (first step); and

[0092] The substituent b is introduced into the intermediate product while the intermediate product is dissolved in a solvent B different from the solvent A, thereby synthesizing a β-1,3-glucan derivative G (second step).

[0093] The first step can be carried out in detail by the following method. First, β-1,3-glucan is dissolved in solvent A to prepare the first solution. β-1,3-glucan has the same structure as β-1,3-glucan derivative G, except for the case where it is composed only of unsubstituted glucose units. Solvent A preferably contains a high-polarity organic solvent. Examples of high-polarity organic solvents include dimethylacetamide (DMAc), dimethyl sulfoxide (DMSO), formic acid, dimethylformamide, and the like. Solvent A preferably contains DMAc as a high-polarity organic solvent. When preparing the first solution, in order to improve the solubility of β-1,3-glucan in solvent A, a salt such as LiCl may be further added. Furthermore, in order to fully dissolve β-1,3-glucan in solvent A, solvent A may also be heated.

[0094] Next, a first reactant for introducing substituent a into β-1,3-glucan is added to the first solution. The first reactant is typically an acylating agent. Examples of the acylating agent include acyl chlorides and acid anhydrides. Furthermore, as required, a basic compound for promoting the reaction between β-1,3-glucan and the first reactant may be added to the first solution. Examples of the basic compound include amine compounds such as pyridine and triethylamine.

[0095] Next, the hydroxyl group contained in the β-1,3-glucan is reacted with the first reactant to introduce the substituent a into the β-1,3-glucan. As an example, when an acylating agent is used as the first reactant, an acyl group is introduced into the β-1,3-glucan as the substituent a. The conditions for the reaction of the β-1,3-glucan with the first reactant can be appropriately set according to the type of the β-1,3-glucan or the first reactant.

[0096] The intermediate product can be synthesized by reacting β-1,3-glucan with the first reactant. In the intermediate product, the DS value of the substituent (acyl group) is not particularly limited, and is, for example, 1.0 or more. The upper limit of the DS value is, for example, 2.0. In the intermediate product, a part of the hydroxyl group contained in β-1,3-glucan remains.

[0097] Next, a solid intermediate product is obtained by precipitating the intermediate product from the first solution or removing the solvent A from the first solution. The intermediate product may be subjected to a purification treatment as necessary.

[0098] The second step can be carried out in detail by the following method. First, the intermediate product is dissolved in a solvent B different from solvent A to prepare the second solution. Solvent B preferably comprises an organic solvent (low-polarity organic solvent) having a polarity lower than solvent A. Solvent B preferably comprises at least one selected from the group consisting of toluene, cyclohexane and tetrahydrofuran as a low-polarity organic solvent, more preferably comprises toluene. The second solution may also not comprise salts such as LiCl.

[0099] Next, a second reactant for introducing the substituent b into the intermediate product is added to the second solution. As the second reactant, the first reactant mentioned above can be cited, and it can also be the same as the first reactant. Furthermore, as needed, a basic compound for promoting the reaction of the intermediate product and the second reactant can also be added to the second solution. It should be noted that the intermediate product can also be dissolved in a mixed solution containing a basic compound and a solvent B to prepare the second solution. As the basic compound, the above-mentioned compounds can be cited.

[0100] Next, by reacting the hydroxyl group contained in the intermediate product with the second reactant, the substituent b is introduced into the intermediate product. The above-mentioned substituent a and substituent b may be different from each other, preferably the same as each other. The conditions for the reaction of the intermediate product with the second reactant can be appropriately set according to the type of the intermediate product or the second reactant.

[0101] The reaction of the intermediate product with the second reactant can synthesize the β-1,3-glucan derivative G. The solid β-1,3-glucan derivative G can be obtained by precipitating the β-1,3-glucan derivative G from the second solution or removing the solvent B from the second solution. The β-1,3-glucan derivative G can be purified as needed.

[0102] Patent Document 1 discloses that an acyl group is introduced into paramylon in a state where paramylon is not dissolved in a solvent (a heterogeneous system), thereby synthesizing a paramylon derivative. According to the research of the present inventors, when a paramylon derivative is synthesized by the above method, there is a tendency to generate an unwanted gel. It is speculated that the gel is generated by condensation of the paramylon derivatives with each other due to the hydroxyl groups remaining in the paramylon derivative.

[0103] In contrast, in the manufacturing method of the present embodiment, in both the first step and the second step, the introduction reaction of the substituent is carried out in a state where the β-1,3-glucan and the intermediate product are dissolved in a solvent (homogeneous system). By this method, the above-mentioned condensation reaction is suppressed, thereby suppressing the generation of unwanted gel. By using the β-1,3-glucan derivative G prepared by the manufacturing method, an adhesive composition with less unwanted gel can be prepared. As described above, in the case of preparing an adhesive sheet by such an adhesive composition, there is a tendency to suppress the generation of bumps on the surface of the adhesive sheet.

[0104] It should be noted that in the first step of the production method of the present embodiment, as the substituent a is introduced into β-1,3-glucan, there is a tendency for the solubility of the intermediate product in the solvent A to change. In detail, in the first step, as the reaction proceeds, there is a tendency for the intermediate product to precipitate from the first solution. The precipitation of the intermediate product from the first solution is particularly significant when the carbon number of the substituent a is large (for example, the carbon number is 8 or more). When the intermediate product precipitates, there is a tendency for the speed of the reaction of introducing the substituent a to decrease significantly. Therefore, it is difficult to introduce the substituent into β-1,3-glucan with a sufficient degree of substitution only in the first step. In the production method of the present embodiment, by combining the first step and the second step, it is possible to easily synthesize the β-1,3-glucan derivative G into which the substituent is introduced with a sufficient degree of substitution.

[0105] [additive]

[0106] The adhesive composition may further include additives other than the β-1,3-glucan derivative G. Examples of the additives include other base polymers, tackifiers, crosslinking agents, photoradical generators, radical polymerizable compounds, solvents, viscosity modifiers, leveling agents, plasticizers, fillers, stabilizers, preservatives, anti-aging agents, etc. The adhesive composition may further include a tackifier as an additive, and may further include a crosslinking agent as an additive.

[0107] As other base polymers, (meth)acrylic resins and the like are mentioned.

[0108] The tackifier is a component that improves 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.

[0109] 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., preferably terpene resins and aromatic modified terpene resins. Examples of the terpene resin include α-pinene polymers, β-pinene polymers, dipentene polymers, etc.

[0110] Examples of rosin-based resins include disproportionated rosin, rosin esters, phenol-modified rosin, hydrogenated rosin, polymerized rosin, maleated rosin, fumarated rosin, disproportionated maleic acid-modified rosin resins, and rosin esters and phenol-modified rosin are preferred. Examples of rosin esters include pentaerythritol ester-modified rosin resins, and the like.

[0111] 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, particularly hydrogenated products of aromatic (C9) petroleum resins.

[0112] The amount of the thickener is not particularly limited. As an example, the amount of the thickener is, for example, 5 parts by weight or more, 10 parts by weight or more, or 20 parts by weight or more, relative to 100 parts by weight of the β-1,3-glucan derivative G. The amount of the thickener is, for example, 150 parts by weight or less, 100 parts by weight or less, 80 parts by weight or less, 60 parts by weight or less, or 40 parts by weight or less, relative to 100 parts by weight of the β-1,3-glucan derivative G.

[0113] The crosslinking agent is preferably capable of reacting with the hydroxyl group remaining in the β-1,3-glucan 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 also contain a compound C containing a (meth)acryloyl group and a hydroxyl reactive functional group. The crosslinking agent preferably contains an isocyanate crosslinking agent.

[0114] 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, xylylene diisocyanate (XDI)-type crosslinking agents, and hydrogenated xylylene diisocyanate (H6XDI) (also known as 1,3-bis(isocyanomethyl)cyclohexane)-type crosslinking agents.

[0115] As HDI type crosslinking agents, trimethylolpropane adducts of HDI, isocyanurates of HDI, allophanates of HDI, etc. can be cited, preferably isocyanurates of HDI. When isocyanurates of HDI are used, there is a tendency that the components of the adhesive composition can be suppressed from remaining on the adherend. As TDI type crosslinking agents, trimethylolpropane adducts of TDI, isocyanurates of TDI, allophanates of TDI, etc. can be cited. As XDI type crosslinking agents, trimethylolpropane adducts of XDI, isocyanurates of XDI, allophanates of XDI, etc. can be cited. As H6XDI type crosslinking agents, trimethylolpropane adducts of H6XDI, isocyanurates of H6XDI, allophanates of H6XDI, etc. can be cited.

[0116] 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 listed, 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.

[0117] Compound C can react with the hydroxyl group remaining in the β-1,3-glucan derivative G through the hydroxyl-reactive functional group. By reacting compound C with the β-1,3-glucan derivative G, a (meth)acryloyl group can be introduced into the β-1,3-glucan derivative G. By reacting a plurality of β-1,3-glucan derivatives G with each other using a (meth)acryloyl group, the β-1,3-glucan derivative G can be cross-linked. It should be noted that in this specification, the reaction product of the β-1,3-glucan derivative G and compound C is sometimes simply referred to as β-1,3-glucan derivative G.

[0118] As the compound C containing an isocyanate group as a hydroxyl-reactive functional group, there can be mentioned isocyanoalkyl (meth)acrylate, isocyano(meth)acryloyl (poly)oxyalkylene alkyl ester, etc. Specific examples of isocyanoalkyl (meth)acrylate include isocyanomethyl (meth)acrylate, isocyanoethyl (meth)acrylate, isocyanopropyl (meth)acrylate, isocyanobutyl (meth)acrylate, etc. As isocyano(meth)acryloyl (poly)oxyalkylene alkyl ester, there can be mentioned isocyano(meth)acryloyl polyoxyethylene ethyl isocyanate, isocyano(meth)acryloyloxyethyloxyethyl isocyanate, etc.

[0119] 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-isocyanoethyl acrylate), Karenz MOI (manufactured by Showa Denko, 2-isocyanoethyl methacrylate), and Karenz MOI-EG (manufactured by Showa Denko, 2-(2-methacryloyloxyethyloxy)ethyl isocyanate).

[0120] The amount of the crosslinking agent is not particularly limited. As an example, the amount of the crosslinking agent 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 relative to 100 parts by weight of the β-1,3-glucan derivative G. The amount of the crosslinking agent relative to 100 parts by weight of the β-1,3-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 crosslinking agent relative to 100 parts by weight of the β-1,3-glucan derivative G may be 5.0 parts by weight or less, or 3.0 parts by weight or less depending on the circumstances.

[0121] In the case where the adhesive composition includes the above-mentioned compound C as a crosslinking agent, the adhesive composition preferably further includes a photoradical generator and may also 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.

[0122] As the photoradical 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 photoradical generator, commercially available products can be used. As commercially available products, Omnirad184, 369, 500, 651, 819, 907, 784, 2959 (above, manufactured by IGM Resins BV), CGI-1700, -1750, -1850, CG24-61, Darocur 1116, 1173 (above, manufactured by BASF), etc. can be cited.

[0123] The amount of the photoradical generator is not particularly limited. As an example, the amount of the photoradical generator 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, relative to 100 parts by weight of the β-1,3-glucan derivative G. The amount of the photoradical generator 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, relative to 100 parts by weight of the β-1,3-glucan derivative G.

[0124] The radical polymerizable compound is, for example, a compound having a radical polymerizable unsaturated double bond, and examples thereof include (meth)acrylic acid, (meth)acrylamide, aromatic vinyl, vinyl ester, acrylonitrile, etc. (Meth)acrylic acid refers to acrylic acid and / or methacrylic acid.

[0125] 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. The (meth)acrylic acid monomer 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.

[0126] 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.

[0127] Examples of the carboxyl group-containing (meth)acrylic monomer include (meth)acrylic acid, and examples of the hydroxyl group-containing (meth)acrylic monomer include 2-hydroxyethyl (meth)acrylate, 3-hydroxypropyl (meth)acrylate, and 4-hydroxybutyl (meth)acrylate.

[0128] 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.

[0129] As the alkoxypolyoxyalkylene glycol mono(meth)acrylate, alkoxypolyoxyethylene glycol mono(meth)acrylate, particularly methoxypolyoxyethylene glycol mono(meth)acrylate, etc. can be mentioned.

[0130] 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.

[0131] 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.

[0132] The amount of the radical polymerizable compound is not particularly limited. As an example, the amount of the radical polymerizable compound 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 3 parts by weight or more, relative to 100 parts by weight of the β-1,3-glucan derivative G. The amount of the radical polymerizable compound is, for example, 100 parts by weight or less, 10 parts by weight or less, or 7 parts by weight or less, relative to 100 parts by weight of the β-1,3-glucan derivative G.

[0133] The solvent may be an organic solvent or water. The organic solvent may be low polar or high polar. Examples of low polar organic solvents include aromatic compounds, alicyclic compounds, saturated chain hydrocarbon compounds, etc. Examples of aromatic compounds include toluene, etc. Examples of alicyclic compounds include cyclohexane, methylcyclohexane, etc. Examples of saturated chain hydrocarbon compounds include pentane, hexane, heptane, etc.

[0134] Examples of the highly polar organic solvent include ketones, esters, and alcohols. Examples of ketones include methyl ethyl ketone, esters include ethyl acetate, and alcohols include methanol and ethanol.

[0135] 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.

[0136] (Embodiments of Adhesive Sheet)

[0137] An example of the pressure-sensitive adhesive sheet 1 of the present embodiment is shown in Figure 1 The adhesive sheet 1 is formed from the above-mentioned adhesive composition. In the adhesive sheet 1, the generation of irregularities on the surface is suppressed. In other words, the adhesive sheet 1 has a smooth surface. The thickness of the adhesive sheet 1 is not particularly limited, and is, for example, 1 μm to 1000 μm.

[0138] 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 substances described later with respect to the laminate can be used. Next, the coating film is dried, thereby obtaining the adhesive sheet 1. The drying of the coating film can be carried out, 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 it can also be above 100°C. The heating time of the coating film is not particularly limited, for example, it is above 5 minutes, and it can also be above 30 minutes. In the case where the adhesive composition contains a photoradical generator, the coating film can also be irradiated with light during or after the drying of the coating film.

[0139] The gel fraction of the adhesive sheet 1 is not particularly limited, and may be, for example, 1% or more, 5% or more, 10% or more, 30% or more, 50% or more, or 60% or more. The upper limit of the gel fraction of the adhesive sheet 1 is, for example, 90%. According to the adhesive composition, since the generation of unnecessary gel is suppressed, the value of tanδ at 200°C can be maintained at 0.7 or more, and the gel fraction of the adhesive sheet 1 can be adjusted to 50% or more.

[0140] The gel fraction of the adhesive sheet 1 can be evaluated, for example, by the following method. First, a portion of the adhesive sheet 1 is scraped to obtain a small piece. Then, the obtained small piece is wrapped with a stretched porous film of polytetrafluoroethylene and tied with a kite string. In this way, a test piece can be obtained. As a stretched porous film, for example, NTF1122 (average pore size 0.2 μm) manufactured by Nitto Denko Corporation can be used. Next, the total weight (weight C) of the small piece of the adhesive sheet 1, the stretched porous film and the kite string is measured. It should be noted that the total weight of the stretched porous film and the kite string used is defined as weight B. Next, the test piece is immersed in a container filled with toluene and allowed to stand at 23°C for 1 week. After standing, the test piece is taken out of the container, dried in a dryer set at 130°C for 2 hours, and then the weight A of the test piece is measured. Based on the following formula, the gel fraction of the adhesive sheet 1 can be calculated based on weight A, weight B and weight C.

[0141] Gel fraction (weight %) = (A-B) / (C-B) × 100

[0142] The adhesive sheet 1 preferably has an appropriate peeling force. As an example, the peeling force F of the adhesive sheet 1 measured by the following test is, for example, 0.1N / 20mm or more, and may also be 0.5N / 20mm or more, 1N / 20mm or more, 2N / 20mm or more, 3N / 20mm or more, 4N / 20mm or more, and further 5N / 20mm or more. The upper limit of the peeling force F of the adhesive sheet 1 is not particularly limited, and is, for example, 20N / 20mm.

[0143] 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.

[0144] Next, under an environment of 23°C and 50% RH, the test piece 25 was overlapped with the stainless steel test plate 21 by means of the adhesive sheet 1, and a 2 kg roller was moved back and forth once to press them together. As the stainless steel test plate 21, for example, a SUS304BA plate was used. After being left in this state for 30 minutes, as shown in FIG. Figure 2As shown, they are set in a tensile test device. Specifically, one end of the stainless steel test plate 21 is fixed to the lower fixture 31 of the tensile test device, and the end of the test piece 25 on the lower fixture 31 side is folded 180° and fixed to the upper fixture 30 of the tensile test device. 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.

[0145] (Embodiment of Laminated Body)

[0146] 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 in direct 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.

[0147] 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 also 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.

[0148] The release liner 3 is, for example, a sheet having a release treatment applied to the 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.

[0149] 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.

[0150] 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.

[0151] The above-mentioned laminated bodies 10 and 11 can be distributed and stored in the form of a roll body in which a belt-shaped laminated body is rolled up, or in the form of a single-sheet laminated body, for example.

[0152] Example

[0153] Hereinafter, the present invention will be described in further detail using Examples and Comparative Examples, but the present invention is not limited thereto.

[0154] (Example 1)

[0155] [1st step]

[0156] First, 5.19 g of paramylon (the amount of glucose unit substance is 32.0 mmol) was prepared as β-1,3-glucan, and it was dried under reduced pressure at 200 Pa and 60°C for 1 hour. Furthermore, 4.07 g of LiCl (3 equivalents (96.0 mmol) relative to the glucose unit of paramylon) was prepared and dried at 130°C for 1 hour. Next, paramylon and LiCl were placed in a 3L flask, and nitrogen was supplied at a flow rate of 0.5 L / min for 10 minutes, thereby making the flask into a dry nitrogen atmosphere. Next, 500 mL of dehydrated DMAc was added as solvent A, and the paramylon was dissolved in DMAc by stirring at 90°C for 1 hour to prepare the first solution. At this time, the heating of DMAc was performed using a water bath. The stirring was performed using a Teflon stirring blade at 150 rpm. DMAc was added to the flask and stirred, and the suspension of paramylon was changed into a transparent solution (first solution).

[0157] Next, the heating of DMAc was stopped, and 13.98 mL (128.0 mmol) of pyridine was added. Then, 17.3 mL of myristoyl chloride (2 equivalents (64.0 mmol) relative to the glucose unit of paramylon) was added dropwise at 80°C. After the addition was completed, the mixture was heated to 90°C using a water bath and stirred at 150 rpm for 1 hour. Thus, the reaction between paramylon and myristoyl chloride proceeded, and a crude product containing an intermediate product was obtained.

[0158] Next, stop heating, lower the temperature to 60°C, and then add 1L of methanol. In this way, the remaining myristoyl chloride is inactivated and the target intermediate product is precipitated. Next, remove the supernatant and recover the precipitate by Kiriyama filtration (filter paper: 5A). The precipitate is dissolved in 400mL of tetrahydrofuran and reprecipitated using 1.6L of a mixed solution of methanol and water (1:1). The precipitate is air-dried overnight and dried under reduced pressure at 200Pa and 60°C for 4 hours to obtain an intermediate product having a structure in which a myristoyl group (acyl group with 14 carbon atoms) is introduced into paramylon. In the intermediate product, the degree of substitution (DS value) of the acyl group is 1.2.

[0159] [Step 2]

[0160] Next, for the intermediate product obtained in the first step, it was dried under reduced pressure at 200 Pa and 60° C. for 4 hours. The intermediate product was placed in a 3L flask, and nitrogen was supplied at a flow rate of 0.5L / min for 10 minutes, thereby making the flask a dry nitrogen atmosphere. Next, 250mL of dehydrated toluene was added as solvent B, and stirred at 60° C. for 15 minutes, and then 250mL of dehydrated pyridine was added and stirred at 60° C. for 15 minutes. Thus, the intermediate product was dissolved in toluene to obtain the second solution. It should be noted that the above-mentioned heating was carried out using a water bath. Stirring was carried out using a Teflon stirring blade at 150rpm.

[0161] Next, heating was stopped, and 34.6 mL of myristoyl chloride (4 equivalents (128.0 mmol) relative to the glucose unit of paramylon) was added dropwise at 60°C. After the addition was completed, the mixture was heated to 90°C using a water bath, and after the temperature was raised, the mixture was stirred at 150 rpm for 1 hour using a Teflon stirring blade. Thus, the intermediate product reacted with myristoyl chloride.

[0162] Next, the heating was stopped, the temperature was lowered to 60°C, and 1L of methanol was added. Thus, the remaining myristoyl chloride was inactivated, and the target paramylon derivative 1 was precipitated. Next, the supernatant was removed by decantation, and the precipitate was dissolved in 500mL of toluene. Next, 2L of methanol was used for reprecipitation. The precipitate was added to 500mL of toluene and left to stand overnight. Next, HOMO DISPER 2.5 (manufactured by PRIMIX) was used to stir at 8000rpm for 5 minutes. Next, 2L of methanol was used for reprecipitation. The precipitate was dried under reduced pressure at 200Pa and 60°C for 4 hours, thereby obtaining a paramylon derivative 1 having a structure in which a myristoyl group (acyl group having 14 carbon atoms) was further introduced into the intermediate product. In the paramylon derivative 1, the DS value of the acyl group was 2.9.

[0163] [Adhesive composition and adhesive sheet]

[0164] First, the synthesized paramylon derivative 1 was dissolved in toluene to prepare an adhesive composition having a solid content concentration of 10 wt%. The adhesive composition was applied to a substrate sheet to prepare a coating film. As the 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 SANGYO). Next, the coating film was dried at 100° C. for 6 minutes, thereby obtaining an adhesive sheet of Example 1. The thickness of the adhesive sheet was 50 μm.

[0165] (Example 2)

[0166] In the first step and the second step, paramylon derivative 2 was synthesized by the same method as in Example 1, except that octanoyl chloride was used instead of myristoyl chloride. At this time, in the first step, an intermediate product having a structure in which an octanoyl group (acyl group having 8 carbon atoms) was introduced into paramylon was obtained. In the intermediate product, the DS value of the acyl group was 1.2. In the second step, paramylon derivative 2 having a structure in which an octanoyl group (acyl group having 8 carbon atoms) was further introduced into the intermediate product was obtained. In paramylon derivative 2, the DS value of the acyl group was 2.9. Furthermore, an adhesive composition was prepared by the same method as in Example 1, except that paramylon derivative 2 was used instead of paramylon derivative 1, to produce an adhesive sheet of Example 2. The thickness of the adhesive sheet was 50 μm.

[0167] (Example 3)

[0168] First, the paramylon derivative 1 synthesized in Example 1 was dissolved in toluene to prepare a toluene solution having a solid content concentration of 10 wt%. Next, an isocyanate-based crosslinking agent (Coronate HX (trimethylolpropane adduct of hexamethylene diisocyanate) manufactured by Tosoh Corporation) was blended into the toluene solution to prepare an adhesive composition. The blending amount of the isocyanate-based crosslinking agent was 2.0 parts by weight relative to 100 parts by weight of the paramylon derivative 1.

[0169] 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 TESTERSANGYO). Next, the coating film was dried at 100° C. for 6 minutes, thereby obtaining an adhesive sheet of Example 3. The thickness of the adhesive sheet was 50 μm.

[0170] (Example 4)

[0171] First, the paramylon derivative 1 synthesized in Example 1 was dissolved in toluene to prepare a toluene solution S1 having a solid content concentration of 10 wt%. Next, a thickener (YS resin PX-1250 manufactured by Yasuhara Chemical Co., Ltd.) was dissolved in toluene to prepare a toluene solution S2 having a solid content concentration of 50 wt%. The toluene solutions S1 and S2 were mixed and stirred to prepare a mixed solution. The toluene solutions S1 and S2 were mixed so that the blending amount of the thickener was 70 parts by weight relative to 100 parts by weight of the paramylon derivative 1.

[0172] Next, an isocyanate crosslinking agent (Coronate HX (trimethylolpropane adduct of hexamethylene diisocyanate) manufactured by Tosoh Corporation) was added to the mixed solution to prepare an adhesive composition. The amount of the isocyanate crosslinking agent added was 2.0 parts by weight per 100 parts by weight of the paramylon derivative 1.

[0173] 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 TESTERSANGYO). Next, the coating film was dried at 100° C. for 6 minutes, thereby obtaining an adhesive sheet of Example 4. The thickness of the adhesive sheet was 50 μm.

[0174] (Comparative Example 1)

[0175] [Paramilin derivatives]

[0176] First, 13.3 g of paramylon (the amount of glucose unit substance is 82.03 mmol) and 1000 mL of dehydrated pyridine (manufactured by Fujifilm Wako Pure Chemical Industries, Ltd.) were added to a reaction container equipped with a condenser, a nitrogen inlet tube, a thermometer, and a stirrer. Then, the obtained mixed solution was heated to 92° C. and stirred for 0.5 hours under a nitrogen atmosphere. The mixed solution was a suspension of paramylon (a heterogeneous system). Then, 133.05 mL (492.2 mmol) of myristoyl chloride (manufactured by Fujifilm Wako Pure Chemical Industries, Ltd.) was added to the mixed solution and stirred at 92° C. for 1 hour. Thus, paramylon reacted with myristoyl chloride.

[0177] 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 methanol being stirred, thereby precipitating a 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, thereby obtaining paramylon derivative 3. Paramylon derivative 3 has a structure in which a myristoyl group (acyl group having 14 carbon atoms) is introduced into paramylon. In paramylon derivative 3, the degree of substitution (DS value) of the acyl group is 2.9.

[0178] [Adhesive composition and adhesive sheet]

[0179] First, the synthesized paramylon derivative 3 was dissolved in toluene to prepare an adhesive composition having a solid content concentration of 10 wt%. The adhesive composition was applied to a substrate sheet to prepare a coating film. As the 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 SANGYO). Next, the coating film was dried at 100° C. for 6 minutes, thereby obtaining an adhesive sheet of Comparative Example 1. The thickness of the adhesive sheet was 50 μm.

[0180] (Reference Example 1)

[0181] In the second step, except that DMAc (solvent A) was used instead of toluene and 4.07 g of LiCl was added to the DMAc, a paramylon derivative 4 having a structure in which a myristoyl group (acyl group having 14 carbon atoms) was introduced into paramylon was synthesized by the same method as in Example 1. The DS value of the acyl group in the paramylon derivative 4 was 1.3. As is known from this result, in the first and second steps, when the same solvent is used to carry out the introduction reaction of the acyl group, especially the acyl group having a large carbon number, it is difficult to adjust the DS value of the acyl group to a high value.

[0182] [Gel fraction]

[0183] The gel fraction of the PSA sheets of Examples and Comparative Examples was determined by the above-mentioned method.

[0184] [Evaluation of concave and convex]

[0185] The surfaces of the pressure-sensitive adhesive sheets of Examples and Comparative Examples were visually observed and the irregularities were evaluated as follows.

[0186] ○: Almost no irregularities were observed on the surface of the pressure-sensitive adhesive sheet, and the surface was smooth.

[0187] ×: Concavities and convexities were observed on the surface of the pressure-sensitive adhesive sheet.

[0188] [tanδ at 200℃]

[0189] The tan δ at 200° C. was determined for the adhesive compositions prepared in the examples and comparative examples by the above method. It should be noted that the evaluation sample for measuring tan δ was prepared by laminating a plurality of adhesive sheets and punching the obtained laminate into a disc shape. The dynamic viscoelasticity measurement was performed using ARES-G2 manufactured by TA Instruments.

[0190] [Peel force F]

[0191] The peel force F of the pressure-sensitive adhesive sheets of Examples and Comparative Examples was measured by the above method. In the measurement of the peel force F, a precision universal testing machine Autograph AG-IS manufactured by Shimadzu Corporation was used as a tensile testing device.

[0192] [Table 1]

[0193]

[0194] The abbreviations in Table 1 are as follows.

[0195] C / HX: isocyanate crosslinking agent (Coronate HX (trimethylolpropane adduct of hexamethylene diisocyanate) manufactured by Tosoh Corporation)

[0196] TF: Tackifier (YS resin PX-1250 manufactured by Yasuhara Chemical Co., Ltd.)

[0197] As can be seen from Table 1, the PSA sheets of the Examples produced using the PSA compositions having a tan δ of 0.7 or more at 200° C. have smoother surfaces than the Comparative Examples. From this result, it is estimated that the PSA sheets of the Examples have less uneven thickness than the Comparative Examples, and thus less uneven adhesive strength.

[0198] The results of Example 1 and Comparative Example 1 show that the gel fraction or the value of tanδ at 200°C varies greatly depending on the method for producing the β-1,3-glucan derivative. In particular, in Example 1, the value of the gel fraction is smaller than that of Comparative Example 1, and it can be considered that there is less unnecessary gel in the adhesive composition. Furthermore, as can be seen from the results of Examples 3 and 4, when an adhesive composition with less unnecessary gel is used, there is a tendency that tanδ at 200°C can be maintained at 0.7 or more even when the gel fraction of the adhesive sheet is increased by using a crosslinking agent.

[0199] Furthermore, when Examples 1, 3, and 4 and Comparative Example 1, which have the same number of carbon atoms in the acyl group introduced into β-1,3-glucan, are compared, the peel force F of the pressure-sensitive adhesive sheets of Examples is greater than that of Comparative Example.

[0200] Industrial Applicability

[0201] The adhesive composition of this embodiment can be used for adhesive tapes.

Claims

1. An adhesive composition comprising a β-1,3-glucan derivative, The adhesive composition has a tan δ at 200° C. of 0.7 or more as determined by the following test. Test: A disk-shaped evaluation sample was prepared using the PSA composition, and the evaluation sample was subjected to dynamic viscoelasticity measurement to determine tan δ at 200°C.

2. The adhesive composition according to claim 1, wherein The tan δ is 4.1 or less.

3. The adhesive composition according to claim 1, wherein The β-1,3-glucan derivative includes an acyl group.

4. The adhesive composition according to claim 3, wherein In the β-1,3-glucan derivative, the degree of substitution (DS value) of the acyl group is 2.6 or more and less than 3.

0.

5. The adhesive composition according to claim 3, wherein The acyl group is represented by the following formula (1): RCO-(1) In the formula (1), R is a hydrocarbon group.

6. The adhesive composition according to claim 5, wherein The hydrocarbon group has 7 to 15 carbon atoms. The adhesive composition according to claim 1 , further comprising a tackifier.

8. The adhesive composition according to claim 7, wherein The tackifier includes at least one selected from the group consisting of terpene resins, rosin resins, and petroleum resins. 9 . The adhesive composition according to claim 1 , further comprising a crosslinking agent.

10. The adhesive composition according to claim 9, wherein The cross-linking agent includes an isocyanate-based cross-linking agent. 11 . A pressure-sensitive adhesive sheet formed from the pressure-sensitive adhesive composition according to claim 1 . 12 . A laminate comprising: the pressure-sensitive adhesive sheet according to claim 11 and a substrate sheet.

13. A method for producing a β-1,3-glucan derivative, The manufacturing method comprises: In a state where β-1,3-glucan is dissolved in solvent A, a substituent a is introduced into the β-1,3-glucan to synthesize an intermediate product into which the substituent a is introduced; as well as The β-1,3-glucan derivative is synthesized by introducing a substituent b into the intermediate product while the intermediate product is dissolved in a solvent B different from the solvent A.

14. The manufacturing method according to claim 13, wherein: The substituent a and the substituent b are the same as each other.

15. The manufacturing method according to claim 13, wherein: The solvent A comprises dimethylacetamide.

16. The manufacturing method according to claim 13, wherein: The solvent B includes at least one selected from the group consisting of toluene, cyclohexane, and tetrahydrofuran.

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