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

Abstract

Provided is an adhesive composition suitable for producing an adhesive sheet having a low glass transition temperature. The adhesive composition according to the present invention comprises a beta-1, 3-glucan derivative G. The beta-1, 3-glucan derivative G has an acyl group a having 8 or more carbon atoms, and an acyl group b having a carbon number different from that of the acyl group a and having 8 or more carbon atoms. 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 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] When a pressure-sensitive adhesive composition is prepared using the β-1,3-glucan derivative disclosed in Patent Document 1, a pressure-sensitive adhesive sheet formed from the pressure-sensitive adhesive composition tends not to exhibit sufficient adhesiveness in a low-temperature environment of about 0° C. or less. According to the research of the present inventors, in order to realize a pressure-sensitive adhesive sheet that exhibits sufficient adhesiveness in a low-temperature environment, it is necessary to adjust the glass transition temperature of the pressure-sensitive adhesive sheet to a low value.

[0010] Therefore, an object of the present invention is to provide a PSA composition suitable for producing a PSA sheet having a low glass transition temperature.

[0011] Solutions for solving problems

[0012] The present invention provides an adhesive composition.

[0013] It contains β-1,3-glucan derivatives,

[0014] The β-1,3-glucan derivative has an acyl group a having 8 or more carbon atoms, and an acyl group b having a carbon number different from that of the acyl group a and having 8 or more carbon atoms.

[0015] Furthermore, the present invention provides a pressure-sensitive adhesive sheet.

[0016] It is formed from the above-mentioned adhesive composition.

[0017] Furthermore, the present invention provides a laminate comprising:

[0018] The above adhesive sheet, and

[0019] Substrate sheet.

[0020] Furthermore, the present invention provides a method for producing a β-1,3-glucan derivative, comprising:

[0021] In a state where β-1,3-glucan is dissolved in a solvent A, an acyl group a having 8 or more carbon atoms is introduced into the β-1,3-glucan to synthesize an intermediate product into which the acyl group a is introduced; and

[0022] The β-1,3-glucan derivative is synthesized by introducing an acyl group b having a carbon number different from that of the acyl group a and having 8 or more carbon numbers into the intermediate product while the intermediate product is dissolved in a solvent B different from the solvent A.

[0023] Effects of the Invention

[0024] According to the present invention, a PSA composition suitable for producing a PSA sheet having a low glass transition temperature can be provided. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] Figure 1 This is a cross-sectional view schematically showing a pressure-sensitive adhesive sheet according to one embodiment of the present invention.

[0026] Figure 2 It is a figure for demonstrating the measurement method of the peeling force of a PSA sheet.

[0027] Figure 3 This is a cross-sectional view schematically showing a laminated body according to one embodiment of the present invention.

[0028] Figure 4 It is a cross-sectional view schematically showing a modified example of the stacked body.

[0029] Figure 5This is a graph showing the results of differential scanning calorimetry of β-1,3-glucan derivatives synthesized in Examples and Comparative Examples. DETAILED DESCRIPTION

[0030] The adhesive composition according to the first aspect of the present invention comprises a β-1,3-glucan derivative,

[0031] The β-1,3-glucan derivative has an acyl group a having 8 or more carbon atoms, and an acyl group b having a carbon number different from that of the acyl group a and having 8 or more carbon atoms.

[0032] In the second aspect of the present invention, for example, in the adhesive composition described in the first aspect, the acyl group a is represented by the following formula (1);

[0033] R1CO-(1)

[0034] In the above formula (1), R1 is a hydrocarbon group having 10 to 15 carbon atoms.

[0035] In a third aspect of the present invention, for example, in the adhesive composition according to the second aspect, R1 is an alkyl group having 10 to 15 carbon atoms.

[0036] In a fourth aspect of the present invention, for example, in the adhesive composition according to any one of the first to third aspects, the acyl group b is represented by the following formula (2);

[0037] R2CO-(2)

[0038] In the above formula (2), R2 is a hydrocarbon group having 7 to 9 carbon atoms.

[0039] In a fifth aspect of the present invention, for example, in the adhesive composition according to the fourth aspect, R2 is an alkyl group having 7 to 9 carbon atoms.

[0040] In a sixth aspect of the present invention, for example, in the PSA composition according to any one of the first to fifth aspects, in the β-1,3-glucan derivative, the total value of the degree of substitution of the acyl group a and the degree of substitution of the acyl group b is 2.6 or more and less than 3.0.

[0041] In a seventh aspect of the present invention, for example, in the adhesive composition according to any one of the first to sixth aspects, in the β-1,3-glucan derivative, the amount of the substance of the acyl group a is a The amount M of the substance with the above acyl group b b The ratio (M a :M b ) is 1:2 to 2:1.

[0042] In an eighth aspect of the present invention, for example, in the pressure-sensitive adhesive composition according to any one of the first to seventh aspects, the β-1,3-glucan derivative has a glass transition temperature of 15.0° C. or less.

[0043] In a ninth aspect of the present invention, for example, in the adhesive composition according to any one of the first to eighth aspects, there is no endothermic peak in a DSC curve prepared by the following test;

[0044] Test: The above-mentioned β-1,3-glucan derivative was placed in a differential scanning calorimeter, and in a nitrogen atmosphere, the temperature was increased from 25°C to 250°C at a heating rate of 15°C / min; then, the temperature was cooled from 250°C to -80°C at a cooling rate of 5°C / min; then, the temperature was increased from -80°C to 250°C at a heating rate of 5°C / min; a DSC curve was prepared based on the data during the second heating.

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

[0046] The laminated body according to the eleventh aspect of the present invention comprises:

[0047] The adhesive sheet according to the tenth aspect; and

[0048] Substrate sheet.

[0049] The production method according to the twelfth aspect of the present invention is a method for producing a β-1,3-glucan derivative, comprising:

[0050] In a state where β-1,3-glucan is dissolved in solvent A, an acyl group a having 8 or more carbon atoms is introduced into the β-1,3-glucan to synthesize an intermediate product into which the acyl group a is introduced; and

[0051] The β-1,3-glucan derivative is synthesized by introducing an acyl group b having a carbon number different from that of the acyl group a and having 8 or more carbon atoms into the intermediate product while the intermediate product is dissolved in a solvent B different from the solvent A.

[0052] In a 13th aspect of the present invention, for example, in the production method according to the 12th aspect, the solvent A contains dimethylacetamide.

[0053] In a fourteenth aspect of the present invention, for example, in the production method according to the twelfth or thirteenth aspect, the solvent B contains at least one selected from the group consisting of toluene, cyclohexane, and tetrahydrofuran.

[0054] Hereinafter, the present invention will be described in detail, but the following description is not intended to limit the present invention to specific embodiments.

[0055] (Embodiment of Adhesive Composition)

[0056] The adhesive composition of the present embodiment includes a β-1,3-glucan derivative G. The β-1,3-glucan derivative G has an acyl group a and an acyl group b. The acyl group a has 8 or more carbon atoms. The acyl group b has a carbon number different from that of the acyl group a, and the carbon number is 8 or more. In this way, the β-1,3-glucan derivative G has at least two types of acyl groups.

[0057] [β-1,3-Glucan derivatives]

[0058] 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.

[0059] 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.

[0060] 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.

[0061] The glucose unit U has a structure in which acyl groups a and b are introduced into a hydroxyl group included in an unsubstituted glucose unit, for example. As an example, the glucose unit U has an ester group formed by introducing the acyl group a or b into the hydroxyl group.

[0062] As described above, the carbon number of the acyl group a is 8 or more. The carbon number of the acyl group a is preferably 11 or more, and may be 12 or more, and further may be 13 or more. The carbon number of the acyl group a is, for example, 19 or less, and may be 18 or less, 17 or less, 16 or less, 15 or less, and further may be 14 or less. The carbon number of the acyl group a is preferably 11 to 16.

[0063] The acyl group a is represented by, for example, the following formula (1).

[0064] R1CO-(1)

[0065] In formula (1), R1 is a hydrocarbon group. The hydrocarbon group may have a substituent, but preferably has no substituent. In R1, the carbon number of the hydrocarbon group is, for example, 7 or more, or 10 or more, 11 or more, or 12 or more. The carbon number of the hydrocarbon group is, for example, 18 or less, or 17 or less, 16 or less, 15 or less, 14 or less, or 13 or less. The carbon number of the hydrocarbon group is preferably 10 to 15.

[0066] In R1, examples of hydrocarbon groups 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 aliphatic hydrocarbon groups include saturated aliphatic hydrocarbon groups and unsaturated aliphatic hydrocarbon groups, preferably saturated aliphatic hydrocarbon groups (alkyl groups). Examples of unsaturated aliphatic hydrocarbon groups include alkenyl groups.

[0067] R1 is preferably an alkyl group having 10 to 15 carbon atoms. Examples of the alkyl group having 10 to 15 carbon atoms include decyl, undecyl, dodecyl, tridecyl, tetradecyl, and pentadecyl.

[0068] Specific examples of the acyl group a represented by formula (1) include lauroyl, myristoyl, palmitoyl, etc., preferably myristoyl. Acyl group a is not limited to these specific examples as long as it has a carbon number different from that of acyl group b and the carbon number is 8 or more.

[0069] As described above, the carbon number of the acyl group b is 8 or more. The carbon number of the acyl group b is preferably 10 or less, and may be 9 or less. The carbon number of the acyl group b is preferably 8-10.

[0070] The acyl group b is represented by, for example, the following formula (2).

[0071] R2CO-(2)

[0072] In formula (2), R2 is a hydrocarbon group. The hydrocarbon group may have a substituent, but preferably has no substituent. In R2, the number of carbon atoms in the hydrocarbon group is, for example, 7 or more. The number of carbon atoms in the hydrocarbon group is, for example, 9 or less, or 8 or less. The number of carbon atoms in the hydrocarbon group is preferably 7 to 9.

[0073] In R2, as a hydrocarbon group, for example, an aliphatic hydrocarbon group, an alicyclic hydrocarbon group, and an aromatic hydrocarbon group can be listed, and an aliphatic hydrocarbon group is preferred. The aliphatic hydrocarbon group may be branched, but is preferably straight-chained. As an aliphatic hydrocarbon group, for example, a saturated aliphatic hydrocarbon group and an unsaturated aliphatic hydrocarbon group can be listed, and a saturated aliphatic hydrocarbon group (alkyl) is preferred. As an unsaturated aliphatic hydrocarbon group, for example, an alkenyl group can be listed.

[0074] R2 is preferably an alkyl group having 7 to 9 carbon atoms. Examples of the alkyl group having 7 to 9 carbon atoms include a heptyl group, an octyl group, and a nonyl group.

[0075] Specific examples of the acyl group b represented by formula (2) include octanoyl, nonanoyl, decanoyl, etc., preferably octanoyl. However, the acyl group b is not limited to these specific examples as long as it has a carbon number different from that of the acyl group a and the carbon number is 8 or more.

[0076] In the β-1,3-glucan derivative G, the total value T of the degree of substitution (DS value) of acyl group a and the degree of substitution (DS value) of acyl group b is, for example, greater than 2.5, and may be 2.6 or more, 2.7 or more, 2.8 or more, and further 2.9 or more. When the total value T 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 total value T is, for example, less than 3.0, and may be 2.9 or less, or 2.8 or less, depending on the circumstances. In this case, when an adhesive sheet is formed from an adhesive composition containing the β-1,3-glucan derivative G, the hydroxyl group remaining in the β-1,3-glucan derivative G can react with the following crosslinking agent. The total value T is preferably 2.6 or more and less than 3.0.

[0077] It should be noted that the above-mentioned total value T specifically refers to the number of acyl groups (acyl groups a and b) contained in the β-1,3-glucan derivative G relative to one glucose unit. When the total value T 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 total value T 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. Based on the obtained NMR spectrum, the peaks derived from the hydrogen atoms directly bonded to the carbon atoms at positions 1 to 6 in the glucose unit of the β-1,3-glucan derivative G and the peaks derived from the acyl groups are determined. Based on the integrated values ​​of these peaks, the total value T can be determined.

[0078] In the β-1,3-glucan derivative G, the DS value of the acyl group a is not particularly limited, and is, for example, 1.0 to 2.0. Similarly, the DS value of the acyl group b is not particularly limited, and is, for example, 1.0 to 2.0.

[0079] In the β-1,3-glucan derivative G, the amount of acyl group a is M a The amount of substance M with acyl group b b The ratio (M a :M b ) is not particularly limited, and is, for example, 1:2 to 2:1. a :M b ) is equivalent to the ratio of the DS value of acyl group a to the DS value of acyl group b. a :M b ) can be calculated from the composition of the acyl groups a and b, the above-mentioned total value T, and the integrated value of the peak derived from the acyl groups (acyl groups a and b) in the NMR spectrum of the β-1,3-glucan derivative G.

[0080] The β-1,3-glucan derivative G is preferably a paramylon derivative. The paramylon derivative is represented by, for example, the following formula (3).

[0081]

[0082] In formula (3), n is an integer. X is independently a hydrogen atom, an acyl group a or an acyl group b. At least one of the plurality of X is an acyl group a. Similarly, at least one of the plurality of X is an acyl group b.

[0083] 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.

[0084] 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.

[0085] Since the β-1,3-glucan derivative G has acyl groups a and b, there is a tendency for the glass transition temperature Tg to be low. The glass transition temperature of the β-1,3-glucan derivative G is, for example, 15.0°C or less, and may be 14.0°C or less, 13.0°C or less, 12.0°C or less, 11.0°C or less, or further 10.0°C or less. The lower limit of the glass transition temperature of the β-1,3-glucan derivative G is not particularly limited, and is, for example, -10.0°C.

[0086] The glass transition temperature of the β-1,3-glucan derivative G can be determined by the following method. First, a disc-shaped evaluation sample is prepared using the β-1,3-glucan derivative G. The diameter of the evaluation sample, for example, is 7.9 mm on the bottom surface and is about 0.7 mm thick. The evaluation sample can be prepared, for example, by the following method. First, a sheet consisting of a β-1,3-glucan derivative G is prepared. The sheet can also be an adhesive sheet formed by an adhesive composition comprising a β-1,3-glucan derivative G and a solvent. The preparation of the adhesive sheet can be carried out by the following method. Then, a plurality of sheets are stacked, and the obtained laminate is punched into a disc shape. Thus, an evaluation sample can be prepared.

[0087] Next, the sample for evaluation is sandwiched between parallel plates and placed in a dynamic viscoelasticity measuring device. As a dynamic viscoelasticity measuring device, for example, ARES-G2 manufactured by TA Instruments can be used. Using the dynamic viscoelasticity measuring device, dynamic viscoelasticity measurement is performed under the following conditions.

[0088] (Measurement conditions)

[0089] Frequency: 1Hz

[0090] Deformation mode: Twist

[0091] Measuring temperature: -60℃~200℃

[0092] Heating rate: 5℃ / min

[0093] Next, based on the results of the dynamic viscoelasticity measurement, a graph showing the relationship between temperature and tanδ (loss tangent) was prepared. It should be noted that tanδ is equivalent to the ratio G" / G' of the loss elastic modulus G" to the storage modulus G'. The peak of tanδ can be determined based on the prepared graph, and the temperature corresponding to the peak is regarded as the glass transition temperature of the β-1,3-glucan derivative G.

[0094] Furthermore, the β-1,3-glucan derivative G has a tendency to have low crystallinity due to the presence of acyl groups a and b. As an example, in the present embodiment, in the DSC curve prepared by the following Test 1, there is no endothermic peak.

[0095] Test 1: The β-1,3-glucan derivative was placed in a differential scanning calorimeter and heated from 25°C to 250°C at a heating rate of 15°C / min in a nitrogen atmosphere. Then, it was cooled from 250°C to -80°C at a cooling rate of 5°C / min. Then, it was heated from -80°C to 250°C at a heating rate of 5°C / min. A DSC curve was prepared based on the data from the second heating.

[0096] The absence of an endothermic peak in the DSC curve means that the β-1,3-glucan derivative G does not crystallize during cooling in the above-mentioned test 1. It should be noted that, as can be seen from the results of the following comparative example 2, when the above-mentioned test 1 is performed on a β-1,3-glucan derivative having a single acyl group with a large carbon number, there is a tendency for an endothermic peak to appear in the DSC curve. That is, the β-1,3-glucan derivative having a single acyl group with a large carbon number tends to have high crystallinity due to the acyl group.

[0097] It should be noted that whether there is an endothermic peak in the DSC curve can be determined, for example, by the following method. First, the acyl group with a larger carbon number among acyl group a and acyl group b (typically acyl group a) is introduced into β-1,3-glucan to synthesize a β-1,3-glucan derivative for testing. The β-1,3-glucan derivative for testing, for example, has a structure in which the acyl group b of the β-1,3-glucan derivative G is substituted with the acyl group a. The β-1,3-glucan derivative for testing can be synthesized by the same method as the method for producing the β-1,3-glucan derivative G described below.

[0098] Next, the above-mentioned test 1 is carried out on the test β-1,3-glucan derivative, and a DSC curve is prepared based on the data at the second temperature increase. From the DSC curve, the presence of an endothermic peak can usually be clearly interpreted. The temperature S corresponding to the peak top of the endothermic peak is determined. As an example, in the case of using a paramylon derivative having only lauroyl (carbon number 12) as an acyl group, the temperature S is about -40°C. In the case of using a paramylon derivative having only myristoyl (carbon number 14) as an acyl group, the temperature S is about -15°C. In the case of using a paramylon derivative having only palmitoyl (carbon number 16) as an acyl group, the temperature S is about 10°C. It should be noted that in the DSC curve, usually, the heat flow shows a minimum value at the position of the peak top of the endothermic peak.

[0099] Next, the endothermic amount in the range of the temperature S±30° C. is calculated from the DSC curve of the β-1,3-glucan derivative G. When the calculated endothermic amount is -5 J / g to 5 J / g, it can be determined that there is no endothermic peak in the DSC curve.

[0100] 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.

[0101] The method for producing the β-1,3-glucan derivative G includes, for example:

[0102] In a state where β-1,3-glucan is dissolved in solvent A, the acyl group a is introduced into β-1,3-glucan to synthesize an intermediate product into which the acyl group a is introduced (first step); and

[0103] The acyl group 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).

[0104] 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.

[0105] Next, a first reactant for introducing acyl group 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.

[0106] Next, the hydroxyl group contained in the β-1,3-glucan is reacted with the first reactant to introduce the acyl group a into the β-1,3-glucan. 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.

[0107] 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 acyl group a is not particularly limited, and is, for example, 1.0 to 2.0. In the intermediate product, a part of the hydroxyl group contained in β-1,3-glucan remains.

[0108] 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.

[0109] 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.

[0110] Next, a second reactant for introducing acyl group b into the intermediate product is added to the second solution. As with the first reactant, an acylating agent such as acyl chloride or anhydride can be used as the second reactant. Furthermore, as required, a basic compound for promoting the reaction between 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 solvent B to prepare the second solution. As the basic compound, the above-mentioned compounds can be cited.

[0111] Next, the hydroxyl group contained in the intermediate product is reacted with the second reactant to introduce the acyl group b into the intermediate product. 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.

[0112] 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.

[0113] It should be noted that 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 produce an unwanted gel. It is speculated that the gel is produced by condensation of the paramylon derivatives with each other due to the hydroxyl groups remaining in the paramylon derivative.

[0114] 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. In the case of preparing an adhesive sheet from such an adhesive composition, there is a tendency to suppress the generation of bumps on the surface of the adhesive sheet.

[0115] [additive]

[0116] 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.

[0117] As other base polymers, (meth)acrylic resins and the like are mentioned.

[0118] 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.

[0119] 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.

[0120] 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.

[0121] 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.

[0122] 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.

[0123] 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.

[0124] 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.

[0125] 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.

[0126] 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.

[0127] 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.

[0128] 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.

[0129] 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).

[0130] 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.

[0131] 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.

[0132] 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.

[0133] 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.

[0134] 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.

[0135] 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.

[0136] 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.

[0137] 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.

[0138] 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.

[0139] As the alkoxypolyoxyalkylene glycol mono(meth)acrylate, alkoxypolyoxyethylene glycol mono(meth)acrylate, particularly methoxypolyoxyethylene glycol mono(meth)acrylate, etc. can be mentioned.

[0140] 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.

[0141] 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.

[0142] 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.

[0143] 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.

[0144] 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.

[0145] 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.

[0146] (Embodiments of Adhesive Sheet)

[0147] 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 can be suppressed. In other words, the adhesive sheet 1 can have a smooth surface. The thickness of the adhesive sheet 1 is not particularly limited, and is, for example, 1 μm to 1000 μm.

[0148] 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.

[0149] The adhesive sheet 1 of the present embodiment tends to have a low glass transition temperature Tg due to the β-1,3-glucan derivative G. The glass transition temperature of the adhesive sheet 1 is, for example, 15.0°C or less, and may be 14.0°C or less, 13.0°C or less, 12.0°C or less, 11.0°C or less, or further 10.0°C or less. The lower limit of the glass transition temperature of the adhesive sheet 1 is not particularly limited, and is, for example, -10.0°C. The glass transition temperature of the adhesive sheet 1 can be measured by the same method as the glass transition temperature of the β-1,3-glucan derivative G, except that the adhesive sheet 1 is used instead of the sheet composed of the β-1,3-glucan derivative G.

[0150] When the glass transition temperature of the adhesive sheet 1 is low, the adhesive sheet 1 tends to show sufficient adhesiveness even in a low temperature environment. In other words, the adhesive properties of the adhesive sheet 1 tend not to change easily depending on the environment during use. The adhesive sheet 1 is suitable for use in an environment where the temperature changes, such as outdoors, or in a low temperature environment in winter.

[0151] 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 0.3N / 20mm or more, 0.5N / 20mm or more, 0.7N / 20mm or more, and further 0.8N / 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.

[0152] 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.

[0153] 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.

[0154] (Embodiment of Laminated Body)

[0155] 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.

[0156] 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.

[0157] 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.

[0158] 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.

[0159] 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.

[0160] 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.

[0161] Example

[0162] Hereinafter, the present invention will be described in further detail using Examples and Comparative Examples, but the present invention is not limited thereto.

[0163] (Example 1)

[0164] [1st step]

[0165] 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).

[0166] Next, the heating of DMAc was stopped, and 13.98 mL (128.0 mmol) of pyridine was added. Next, 17.30 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.

[0167] 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 a with 14 carbon atoms) is introduced into paramylon.

[0168] [Step 2]

[0169] 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.

[0170] Next, the heating was stopped, and 21.85 mL of octanoyl 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 octanoyl chloride.

[0171] Next, the heating was stopped, the temperature was lowered to 60°C, and 1 L of methanol was added. Thus, the remaining octanoyl chloride was inactivated, and the target paramylon derivative 1 was precipitated. Next, the supernatant was removed by decantation, and the precipitate was dissolved in 500 mL of toluene. Next, 2.0 L of methanol was used for reprecipitation. The precipitate was added to 500 mL of toluene and allowed to stand overnight. Next, HOMO DISPER 2.5 (manufactured by PRIMIX) was used and stirred at 8000 rpm for 5 minutes. Next, 2.0 L of methanol was used for reprecipitation. The precipitate was air-dried to obtain a paramylon derivative 1 having a structure in which an octanoyl group (acyl group b having 8 carbon atoms) was further introduced into the intermediate product.

[0172] In the paramylon derivative 1, the total value T of the DS value of the acyl group a and the DS value of the acyl group b is 2.9. The amount of substance M of the acyl group a a The amount of substance M with acyl group b b The ratio (M a :M b ) is 1.5:1.5.

[0173] [Adhesive composition and adhesive sheet]

[0174] 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.

[0175] (Example 2)

[0176] In addition to the amount of acyl a substance M a The amount of substance M with acyl group b b The ratio (M a :M b ) was 1.2:1.8, and the addition amounts of myristoyl chloride and octanoyl chloride were adjusted. The paramylon derivative 2 was synthesized by the same method as in Example 1. Furthermore, a pressure-sensitive adhesive composition was prepared by the same method as in Example 1, except that the paramylon derivative 2 was used instead of the paramylon derivative 1, to produce a pressure-sensitive adhesive sheet of Example 2. The thickness of the pressure-sensitive adhesive sheet was 50 μm.

[0177] (Comparative Example 1)

[0178] [1st step]

[0179] 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 a dry nitrogen atmosphere. Next, 500 mL of dehydrated DMAc was added as solvent A, and the mixture was stirred at 90°C for 1 hour, thereby dissolving paramylon in DMAc and preparing 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, thereby changing the suspension of paramylon into a transparent solution (the first solution).

[0180] Next, the heating of DMAc was stopped, and 13.98 mL (128.0 mmol) of pyridine was added. Then, 10.92 mL of octanoyl 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, paramylon and octanoyl chloride reacted to obtain a crude product containing an intermediate product.

[0181] Next, the heating was stopped, the temperature was lowered to 60°C, and 1 L of methanol was added. Thus, the remaining octanoyl chloride was inactivated, and the target intermediate product was precipitated. Next, the supernatant was removed, and the precipitate was recovered by Kiriyama filtration (filter paper: 5A). The precipitate was dissolved in 150 mL of toluene, and reprecipitated using 2.5 L of methanol. The precipitate was air-dried overnight, and dried under reduced pressure at 200 Pa and 60°C for 4 hours, thereby obtaining an intermediate product having a structure in which an octanoyl group (acyl group having 8 carbon atoms) was introduced into paramylon.

[0182] [Step 2]

[0183] 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.

[0184] Next, the heating was stopped, and 21.85 mL of octanoyl 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 octanoyl chloride.

[0185] Next, the heating was stopped, the temperature was lowered to 60°C, and 1 L of methanol was added. Thus, the remaining octanoyl chloride was inactivated, and the target paramylon derivative 3 was precipitated. Next, the supernatant was removed by decantation, and the precipitate was dissolved in 100 mL of toluene. Next, 1.0 L of methanol was used for reprecipitation. The precipitate was added to 500 mL of toluene and left to stand overnight. Next, HOMO DISPER 2.5 (manufactured by PRIMIX) was used to stir at 8000 rpm for 5 minutes. Next, 1.0 L of methanol was used for reprecipitation. The precipitate was air-dried to obtain a paramylon derivative 3 having a structure in which an octanoyl group (acyl group having 8 carbon atoms) was further introduced into the intermediate product. In the paramylon derivative 3, the degree of substitution (DS value) of the acyl group was 2.9.

[0186] [Adhesive composition and adhesive sheet]

[0187] 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.

[0188] (Comparative Example 2)

[0189] [1st step]

[0190] 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 a dry nitrogen atmosphere. Next, 500 mL of dehydrated DMAc was added as solvent A, and the mixture was stirred at 90°C for 1 hour, thereby dissolving paramylon in DMAc and preparing 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, thereby changing the suspension of paramylon into a transparent solution (the first solution).

[0191] Next, the heating of DMAc was stopped, and 13.98 mL (128.0 mmol) of pyridine was added. Then, 17.30 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, paramylon and myristoyl chloride reacted to obtain a crude product containing an intermediate product.

[0192] 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 intermediate product was precipitated. Next, the supernatant was removed, and the precipitate was recovered by Kiriyama filtration (filter paper: 5A). The precipitate was dissolved in 100mL of toluene, and reprecipitated using 500mL of methanol. The precipitate was air-dried overnight, and dried under reduced pressure at 200Pa and 60°C for 4 hours, thereby obtaining an intermediate product having a structure in which a myristoyl group (acyl group having 14 carbon atoms) was introduced into paramylon.

[0193] [Step 2]

[0194] 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.

[0195] Next, the heating was stopped, and 34.60 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 the myristoyl chloride.

[0196] Next, the heating was stopped, the temperature was lowered to 60°C, and 1 L of methanol was added. Thus, the remaining myristoyl chloride was inactivated, and the target paramylon derivative 4 was precipitated. Next, the supernatant was removed by decantation, and the precipitate was dissolved in 450 mL of toluene. Next, 2.0 L of methanol was used for reprecipitation. The precipitate was added to 300 mL of toluene and left to stand overnight. Next, HOMO DISPER 2.5 (manufactured by PRIMIX) was used to stir at 8000 rpm for 5 minutes. Next, 1.2 L of methanol was used for reprecipitation. The precipitate was air-dried to obtain a paramylon derivative 4 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 4, the degree of substitution (DS value) of the acyl group was 2.9.

[0197] [Adhesive composition and adhesive sheet]

[0198] First, the synthesized paramylon derivative 4 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 2. The thickness of the adhesive sheet was 50 μm.

[0199] [Differential Scanning Calorimetry]

[0200] Differential scanning calorimetry was performed on the β-1,3-glucan derivatives synthesized in the examples and comparative examples using the above method to produce a DSC curve. The differential scanning calorimetry was performed by placing about 4 mg of the β-1,3-glucan derivative in an aluminum pan and covering it with a lid, and placing it in a differential scanning calorimeter. As a differential scanning calorimeter, Q2000 manufactured by TA Instruments was used. The results are shown in Figure 5 .according to Figure 5 The DSC curve of was used to confirm the presence or absence of endothermic peak.

[0201] If Figure 5 It is known that an endothermic peak having a peak top at -15°C was observed from the DSC curve when the β-1,3-glucan derivative of Comparative Example 2 was used. Based on this result, the endothermic amount within the range of -15°C±30°C was calculated from the prepared DSC curve for each of the Examples and Comparative Examples.

[0202] [Glass transition temperature]

[0203] The glass transition temperature of the adhesive sheets of the embodiments and comparative examples was determined by the above method. It should be noted that the sample for measuring the glass transition temperature 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.

[0204] It should be noted that the PSA sheets of Examples and Comparative Examples are all composed of only β-1,3-glucan derivatives. Therefore, the measured glass transition temperature of the PSA sheet can be regarded as the glass transition temperature of the corresponding β-1,3-glucan derivative.

[0205] [Peel force F]

[0206] 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.

[0207] [Viscosity test]

[0208] The adhesive sheets of the embodiments and comparative examples were subjected to a stickiness test. The stickiness test was conducted by placing a finger on the surface of the adhesive sheet, leaving it still for 1 second, and then lifting the finger. When the finger was lifted, if the adhesive sheet adhered to the finger for more than 1 second, it was judged to be sticky. If the adhesive sheet separated from the finger before 1 second, it was judged to be non-sticky.

[0209] [Table 1]

[0210]

[0211] (*1) Total value T of DS value of acyl group a and DS value of acyl group b

[0212] (*2) Ratio of the amount of substance Ma of acyl group a to the amount of substance Mb of acyl group b (Ma:Mb)

[0213] As can be seen from Table 1, the adhesive sheet of the embodiment prepared using the adhesive composition containing the β-1,3-glucan derivative having acyl groups a and b has a lower glass transition temperature than the comparative example. Therefore, it can be considered that the adhesive composition of the present embodiment is suitable for preparing an adhesive sheet with a low glass transition temperature. It is estimated that the adhesive sheet of the embodiment has a tendency to show sufficient adhesiveness even in a low temperature environment compared with the comparative example.

[0214] Industrial Applicability

[0215] 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 β-1,3-glucan derivative has an acyl group a having 8 or more carbon atoms, and an acyl group b having a carbon number different from that of the acyl group a and having 8 or more carbon atoms.

2. The adhesive composition according to claim 1, wherein The acyl group a is represented by the following formula (1): R1CO-(1) In the above formula (1), R1 is a hydrocarbon group having 10 to 15 carbon atoms.

3. The adhesive composition according to claim 2, wherein The R1 is an alkyl group having 10 to 15 carbon atoms.

4. The adhesive composition according to claim 1, wherein The acyl group b is represented by the following formula (2): R2CO-(2) In the above formula (2), R2 is a hydrocarbon group having 7 to 9 carbon atoms.

5. The adhesive composition according to claim 4, wherein The R2 is an alkyl group having 7 to 9 carbon atoms.

6. The adhesive composition according to claim 1, wherein In the β-1,3-glucan derivative, the total value of the degree of substitution of the acyl group a and the degree of substitution of the acyl group b is 2.6 or more and less than 3.

0.

7. The adhesive composition according to claim 1, wherein In the β-1,3-glucan derivative, the amount of the acyl group a is M a The amount of substance M with the acyl group b b The ratio (M a :M b ) is 1:2 to 2:

1.

8. The adhesive composition according to claim 1, wherein The glass transition temperature of the β-1,3-glucan derivative is 15.0° C. or less.

9. The adhesive composition according to claim 1, wherein In the DSC curve prepared by the following test, there is no endothermic peak. Experiment: The β-1,3-glucan derivative is placed in a differential scanning calorimeter, and in a nitrogen atmosphere, the temperature is increased from 25°C to 250°C at a heating rate of 15°C / min; then, it is cooled from 250°C to -80°C at a cooling rate of 5°C / min; then, it is heated from -80°C to 250°C at a heating rate of 5°C / min; a DSC curve is prepared based on the data during the second heating. 10 . A pressure-sensitive adhesive sheet formed from the pressure-sensitive adhesive composition according to claim 1 .

11. A laminate comprising: The adhesive sheet according to claim 10, and Substrate sheet.

12. A method for producing a β-1,3-glucan derivative, comprising: In a state where β-1,3-glucan is dissolved in solvent A, an acyl group a having 8 or more carbon atoms is introduced into the β-1,3-glucan to synthesize an intermediate product into which the acyl group a is introduced; as well as The β-1,3-glucan derivative is synthesized by introducing an acyl group b having a carbon number different from that of the acyl group a and having 8 or more carbon numbers into the intermediate product while the intermediate product is dissolved in a solvent B different from the solvent A.

13. The manufacturing method according to claim 12, wherein: The solvent A comprises dimethylacetamide.

14. The manufacturing method according to claim 12, wherein: The solvent B includes at least one selected from the group consisting of toluene, cyclohexane, and tetrahydrofuran.

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