Adhesive composition and adhesive tape

Abstract

This adhesive composition contains: a β-1,3-glucan derivative obtained by introducing an acyl group into β-1,3-glucan; and a terpene-based resin. An adhesive tape (1) comprises an adhesive layer (3) formed from the adhesive composition.

Description

[Technical Field]

[0001] This invention relates to adhesive compositions and adhesive tapes. [Background technology]

[0002] Adhesive compositions containing β-1,3-glucan derivatives, in which an acyl group is introduced to β-1,3-glucan, are known (see, for example, Patent Document 1 below). Since β-1,3-glucan derivatives are polysaccharides of biological origin, the adhesive described in Patent Document 1 has a lower environmental impact compared to conventional adhesives made from petroleum. [Prior art documents] [Patent Documents]

[0003] [Patent Document 1] Japanese Patent Publication No. 2018-154723 [Overview of the project] [Problems that the invention aims to solve]

[0004] Adhesive compositions used in optical applications and other fields where transparency is required demand high adhesive strength, and at the same time, excellent transparency is also required.

[0005] However, the adhesive composition described in Patent Document 1 has the drawback of not being able to satisfy the above-mentioned requirements.

[0006] The present invention provides an adhesive composition and adhesive tape that have high adhesive strength and excellent transparency. [Means for solving the problem]

[0007] The present invention (1) includes an adhesive composition containing a β-1,3-glucan derivative obtained by introducing an acyl group to β-1,3-glucan and a terpene resin.

[0008] In the present invention (2), the pressure-sensitive adhesive composition according to (1) is included, wherein the terpene-based resin is at least one selected from the group consisting of a terpene resin, a hydride of a terpene resin, and a phenol-modified terpene resin.

[0009] In the present invention (3), the pressure-sensitive adhesive composition according to (1) or (2) is included, wherein the acyl group is represented by RCO-, and R is an aliphatic hydrocarbon group having 8 to 14 carbon atoms.

[0010] In the present invention (4), the pressure-sensitive adhesive composition according to any one of (1) to (3) is included, wherein the parts by weight of the terpene-based resin relative to 100 parts by weight of the β-1,3-glucan derivative is 10 parts by weight or more and 100 parts by weight or less.

[0011] In the present invention (5), a pressure-sensitive adhesive tape is included, which comprises a pressure-sensitive adhesive layer formed of the pressure-sensitive adhesive composition according to any one of (1) to (4). [Effects of the Invention]

[0012] The pressure-sensitive adhesive composition and the pressure-sensitive adhesive tape of the present invention have high adhesive strength and excellent transparency. [Brief Description of Drawings]

[0013] [Figure 1] FIG. 1 is a cross-sectional view of one embodiment of the pressure-sensitive adhesive tape of the present invention. [Figure 2] FIG. 2 is a cross-sectional view of another embodiment of the pressure-sensitive adhesive tape. [Figure 3] FIG. 3 is a cross-sectional view of still another embodiment of the pressure-sensitive adhesive tape. [Mode for Carrying Out the Invention]

[0014] [Pressure-sensitive Adhesive Composition] The pressure-sensitive adhesive composition of the present invention contains a β-1,3-glucan derivative and a terpene-based resin.

[0015] [β-1,3-glucan Derivative] A β-1,3-glucan derivative is the base polymer in an adhesive composition. The β-1,3-glucan derivative is a partial acyl compound obtained by acylating a part of hydroxyl groups in glucose contained in β-1,3-glucan with acyl groups. In other words, the β-1,3-glucan derivative is an acyl compound obtained by introducing an acyl group into β-1,3-glucan.

[0016] The acyl group is represented by RCO-. Examples of R include a hydrocarbon group. Examples of the hydrocarbon group include an aliphatic hydrocarbon group, an alicyclic hydrocarbon group, and an aromatic hydrocarbon group, and an aliphatic hydrocarbon group is preferable.

[0017] Examples of the aliphatic hydrocarbon group include a saturated aliphatic hydrocarbon group and an unsaturated aliphatic hydrocarbon group, and a saturated aliphatic hydrocarbon group, that is, an alkyl group is preferable. Examples of the alkyl group include a linear alkyl group and a branched alkyl group, and a linear alkyl group is preferable. The number of carbon atoms in the alkyl group is, for example, 3 or more, and for example, 18 or less. Examples of the linear alkyl group include propyl, butyl, pentyl, hexyl, heptyl, octyl, nonyl, decyl, undecyl, dodecyl, tridecyl, tetradecyl, pentadecyl, hexadecyl, heptadecyl, and octadecyl. Examples of the unsaturated aliphatic hydrocarbon group include an alkenyl group having 3 or more carbon atoms, preferably 5 or more carbon atoms, and for example 18 or less carbon atoms. An example of the alkenyl group is heptadecenyl.

[0018] The number of carbon atoms in the aliphatic hydrocarbon group (alkyl group or alkenyl group) is preferably 6 or more, more preferably 8 or more, and preferably 14 or less. When the number of carbon atoms in the aliphatic hydrocarbon group is not less than the above lower limit, the adhesive force can be sufficiently improved. When the number of carbon atoms in the aliphatic hydrocarbon group is not more than the above upper limit, the adhesive force can be sufficiently improved while providing excellent transparency.

[0019] Specific examples of the acyl group include butanoyl (an example in which R in RCO is C3H7), pentanoyl (an example in which R in RCO is C4H9), hexanoyl (an example in which R in RCO is C5H 11 ), heptanoyl (an example in which R in RCO is C6H 13 ), octanoyl (an example in which R in RCO is C7H 15 ), nonanoyl (an example in which R in RCO is C8H 17 ), decanoyl (an example in which R in RCO is C9H 19 ), lauroyl (i.e., dodecanoyl) (an example in which R in RCO is C 11 H 23 ), myristoyl (i.e., tetradecanoyl) (an example in which R in RCO is C 13 H 27 ), palmitoyl (i.e., hexadecanoyl) (an example in which R in RCO is C 15 H 31 ), stearoyl (i.e., octadecanoyl) (an example in which R in RCO is C 17 H 35 ), oleoyl (an example in which R in RCO is C 17 H 33 ), and nonadecanoyl (an example in which R in RCO is C 18 H 37 ). Preferable examples include octanoyl, nonanoyl, decanoyl, lauroyl, myristoyl, and palmitoyl.

[0020] The types, physical properties and production methods of β-1,3-glucan derivatives are described, for example, in Japanese Unexamined Patent Publication No. 2018-154723.

[0021] The proportion of the β-1,3-glucan derivative in the solid content of the pressure-sensitive adhesive composition is, for example, 50% by weight or more, preferably 60% by weight or more, more preferably 70% by weight or more, and for example, 99% by weight or less, preferably 90% by weight or less, more preferably 80% by weight or less.

[0022] The β-1,3-glucan derivative is 1It is identified by 1H-NMR and FT-IR spectroscopy. Details of the identification are described in Japanese Patent Publication No. 2018-154723.

[0023] [Terpene resins] Terpene resins are tackifiers. In other words, terpene resins are components that enhance the tackiness of an adhesive composition. The adhesive composition of the present invention contains a terpene resin as a tackifier. The terpene resin can improve the tackiness of the adhesive composition while suppressing a decrease in transparency.

[0024] Examples of terpene resins include terpene resins, terpene resin hydrides, aromatically modified terpene resins, phenol-modified terpene resins, and phenol-modified terpene resin hydrides. These can be used individually or in combination.

[0025] Preferably, the terpene resin is at least one selected from the group consisting of terpene resins, terpene resins, and phenol-modified terpene resins, from the viewpoint of further increasing adhesive strength and transparency. More preferably, the terpene resin is a phenol-modified terpene resin, a terpene resin, or a terpene resin, and even more preferably, a terpene resin. Note that phenol-modified terpene resins are sometimes referred to as terpene-phenol resins.

[0026] Furthermore, from the viewpoint of having a high proportion of recyclable resources, terpene resins and terpene resin hydrides are also preferred as terpene resins. Examples of terpene resins include α-pinene polymers, β-pinene polymers, and dipentene polymers. Terpene resins are sometimes referred to as polyterpene resins.

[0027] The amount of terpene resin per 100 parts by weight of β-1,3-glucan derivative is, for example, 5 parts by weight or more, preferably 10 parts by weight or more, and also, for example, 150 parts by weight or less, preferably 100 parts by weight or less, more preferably 80 parts by weight or less, even more preferably 60 parts by weight or less, and particularly preferably 40 parts by weight or less. If the amount of terpene resin per 100 parts by weight of β-1,3-glucan derivative is above the lower limit described above, it is possible to suppress an increase in the viscosity of the adhesive composition solution (described later), and consequently, to suppress defects in the appearance of the adhesive layer (described later). If the amount of terpene resin per 100 parts by weight of β-1,3-glucan derivative is below the upper limit described above, it is possible to suppress the bleed-out of the terpene resin from the adhesive layer in a high-temperature environment, and furthermore, the adhesive strength is increased and the transparency is further enhanced.

[0028] Commercially available terpene resins are used.

[0029] In adhesive compositions, terpene resins are 1 It is identified by 1H-NMR spectroscopy, FT-IR spectroscopy, gel permeation chromatography, and / or mass spectrometry.

[0030] [Additives] The adhesive composition may contain additives in appropriate proportions. Examples of additives include other base polymers (acrylic resins), other tackifiers (rosin resins and petroleum resins), viscosity modifiers, leveling agents, plasticizers, fillers, stabilizers, preservatives, and anti-aging agents.

[0031] To manufacture the adhesive composition, a β-1,3-glucan derivative, a terpene resin, and additives as needed are blended and mixed. Alternatively, a solution containing the adhesive composition can be prepared by dissolving each of the above components in an organic solvent. The solution is sometimes referred to as "solution of the adhesive composition." Examples of organic solvents include low-polarity solvents and high-polarity solvents.

[0032] Examples of low-polarity solvents include aromatic compounds, alicyclic compounds, and saturated hydrocarbon compounds. An example of an aromatic compound is toluene. Examples of alicyclic compounds include cyclohexane and methylcyclohexane. Examples of saturated hydrocarbon compounds include pentane, hexane, and heptane.

[0033] Examples of highly polar solvents include ketones, esters, and alcohols. An example of a ketone is methyl ethyl ketone. An example of an ester is ethyl acetate. Examples of alcohols include methanol and ethanol.

[0034] These organic solvents can be used individually or in combination. Preferably, a low-polarity solvent can be used alone, or a combination of a low-polarity solvent and a high-polarity solvent can be used.

[0035] A β-1,3-glucan derivative and a terpene resin can also be dispersed in water using an emulsifier and / or dispersant to prepare an aqueous dispersion containing the adhesive composition. This aqueous dispersion may sometimes be referred to as an "aqueous dispersion of the adhesive composition."

[0036] The solid content in the solution of the adhesive composition or the aqueous dispersion of the adhesive composition is, for example, 1% by weight or more, preferably 10% by weight or more, and also, for example, 50% by weight or less, preferably 40% by weight or less.

[0037] A hot-melt resin for adhesive compositions can also be prepared by mixing a β-1,3-glucan derivative with a terpene resin using a kneader or the like. Note that the hot-melt resin for adhesive compositions is sometimes simply referred to as "hot-melt resin."

[0038] As shown in Figure 1, a solution of the adhesive composition or an aqueous dispersion of the adhesive composition is applied to the surface of the base sheet 2, and then dried by heating to form the adhesive layer 3. Alternatively, the hot melt resin described above is hot-melt coated onto the surface of the base sheet 2, and then cooled to form the adhesive layer 3. This makes it possible to manufacture an adhesive tape 1 having a base sheet 2 and an adhesive layer 3.

[0039] Examples of materials for the base sheet 2 include resin. Examples of resins include polyester. The thickness of the base sheet 2 is 0.5 μm or more, and also, for example, 900 μm or less.

[0040] The thickness of the adhesive layer 3 is, for example, 1 μm or more, and for example, 1000 μm or less. The thickness of the adhesive tape 1 is, for example, 2 μm or more, and for example, 1100 μm or less.

[0041] Furthermore, as shown in Figure 2, the adhesive tape 1 may also comprise a base sheet 2 and adhesive layers 3 disposed on its front and back surfaces, respectively.

[0042] Alternatively, as shown in Figure 3, a substrate-less adhesive tape 1 can be obtained that does not use a base sheet 2 and only has an adhesive layer 3. The adhesive tape 1 consists only of the adhesive layer 3.

[0043] [Adhesive strength] The adhesive strength of the adhesive layer 3 to the stainless steel plate at 23°C and 50% RH is, for example, 1 N / 20 mm or more, preferably 2 N / 20 mm or more, more preferably 3 N / 20 mm or more, and also, for example, 20 N / 20 mm or less. The method for measuring the adhesive strength of the adhesive layer 3 to the stainless steel plate will be described in detail in a later example.

[0044] The haze of the adhesive layer 3 is, for example, 20% or less, preferably 10% or less, more preferably 5.0% or less, even more preferably 2.0% or less, particularly preferably 1.0% or less, and most preferably 0.5% or less. The method for measuring the haze of the adhesive layer 3 will be described in detail in later examples. A small haze indicates excellent transparency. If the haze of the adhesive layer 3 is below the above upper limit, it is suitable for optical applications. Optical applications include, for example, transparent protective films.

[0045] [Effects of adhesive compositions and adhesive tapes] This adhesive composition contains a terpene resin as an essential tackifier. Therefore, the adhesive composition and adhesive tape exhibit high adhesive strength and excellent transparency. For this reason, the adhesive composition and adhesive tape are suitably used in optical applications, including transparent protective films.

[0046] In contrast, when the adhesive composition contains a rosin-based resin as an essential tackifier, haze increases, resulting in reduced transparency. Furthermore, when the adhesive composition contains a petroleum-based resin as an essential tackifier, the tackiness does not improve sufficiently, and haze increases, leading to reduced transparency.

[0047] [A variation of adhesive tape] In the modified examples, components and processes similar to those in the first embodiment are given the same reference numerals, and their detailed descriptions are omitted. Furthermore, the modified examples can achieve the same effects and advantages as the first embodiment, unless otherwise specified. Moreover, the first embodiment and its modified examples can be combined as appropriate.

[0048] As shown by the dashed lines in Figure 1 and Figure 2, the modified adhesive tape 1 further comprises a release sheet 4 placed on the surface of the adhesive layer 3. [Examples]

[0049] In the following description, specific numerical values ​​such as mixing ratios (content percentages), physical properties, and parameters may be replaced with the corresponding upper limits (numbers defined as "less than or equal to" or "less than") or lower limits (numbers defined as "greater than or equal to" or "greater than") of the mixing ratios (content percentages), physical properties, and parameters described in the "Modes for Carrying Out the Invention" section above. Furthermore, unless otherwise specified in the following description, "parts" and "%" are based on weight.

[0050] [Examples of β-1,3-glucan derivative synthesis]

[0051] Synthesis Example 1 [Synthesis of myristoylated β-1,3-glucan (RCO with 13 carbon atoms in the aliphatic hydrocarbon group)] In a reaction vessel equipped with a condenser, nitrogen inlet tube, thermometer, and stirrer, 13.3 g of β-1,3-glucan (Euglena Co., Ltd.: glucose portion 82.03 mmol) and 1000 mL of anhydrous pyridine (Fujifilm Wako Pure Chemical Industries, Ltd.) were added and stirred for 0.5 hours under a nitrogen atmosphere at 92°C. 133.05 mL of myristoyl chloride (492.2 mmol: Fujifilm Wako Co., Ltd.) was added to the pyridine solution, and the mixture was heated to 92°C and stirred for 1 hour. This prepared the reaction mixture.

[0052] Subsequently, a solid intermediate was obtained from the reaction mixture. First, 2000 mL of methanol was added to the reaction mixture one hour after the start of the reaction, and it was cooled to room temperature. Next, the resulting solid was removed and dissolved in 600 mL of toluene to prepare a toluene solution. The toluene solution was poured into 2000 mL of methanol while stirring to obtain a solid. The solid was washed by repeating the process of dissolving it in toluene and pouring it into methanol three times to obtain a solid. The solid was dried under reduced pressure at 60°C for 4 hours. This yielded myristoylated β-1,3-glucan. In other words, myristoylated β-1,3-glucan is a β-1,3-glucan derivative in which myristoyl is introduced into β-1,3-glucan.

[0053] Synthesis Example 2 [Synthesis of palmitoylated β-1,3-glucan (RCO with 15 carbon atoms in the aliphatic hydrocarbon group)] Palmitoylated β-1,3-glucan was obtained by processing in the same manner as in Synthesis Example 1. However, 133.05 mL (492.2 mmol) of myristoyl chloride was replaced with 150.21 mL (492.2 mmol: Fujifilm Wako Co., Ltd.). In other words, palmitoylated β-1,3-glucan is a β-1,3-glucan derivative obtained by introducing palmitoyl into β-1,3-glucan.

[0054] Synthesis Example 3 [Synthesis of lauroylated β-1,3-glucan (RCO with 11 carbon atoms in the aliphatic hydrocarbon group)] Lauroylated β-1,3-glucan was obtained by processing in the same manner as in Synthesis Example 1. However, 133.05 mL (492.2 mmol) of myristoyl chloride was replaced with 113.81 mL (492.2 mmol: Fujifilm Wako Co., Ltd.). In other words, lauroylated β-1,3-glucan is a β-1,3-glucan derivative obtained by introducing lauroyl into β-1,3-glucan.

[0055] Synthesis Example 4 [Synthesis of octanoylated β-1,3-glucan (RCO with 7 carbon atoms in the aliphatic hydrocarbon group)] Octanoylated β-1,3-glucan was obtained by processing in the same manner as in Synthesis Example 1. However, 133.05 mL (492.2 mmol) of myristoyl chloride was replaced with 84.18 mL (492.2 mmol: Fujifilm Wako Co., Ltd.) of octanoyl chloride. In other words, octanoylated β-1,3-glucan is a β-1,3-glucan derivative obtained by introducing octanoyl into β-1,3-glucan.

[0056] Synthesis Example 5 [Synthesis of butanoylated β-1,3-glucan (RCO with 3 carbon atoms in the aliphatic hydrocarbon group)] Butanoylated β-1,3-glucan was obtained by processing in the same manner as in Synthesis Example 1. However, 133.05 mL (492.2 mmol) of myristoyl chloride was replaced with 50.98 mL (492.2 mmol: Fujifilm Wako Co., Ltd.) of butanoyl chloride. In other words, butanoylated β-1,3-glucan is a β-1,3-glucan derivative obtained by introducing butanoyl into β-1,3-glucan.

[0057] Synthesis Example 6 [Synthesis of oleoyl-modified β-1,3-glucan (RCO with 17 carbon atoms in the aliphatic hydrocarbon group)] Oleoylated β-1,3-glucan was obtained by processing in the same manner as in Synthesis Example 1. However, 133.05 mL (492.2 mmol) of myristoyl chloride was replaced with 162.38 mL (492.2 mmol: Fujifilm Wako Co., Ltd.) of oleoyl chloride. In other words, oleoylated β-1,3-glucan is a β-1,3-glucan derivative obtained by introducing oleoyl into β-1,3-glucan.

[0058] [Manufacturing of adhesive tape]

[0059] [Example 1] A toluene solution of myristoylated β-1,3-glucan (solid content concentration of 10% by weight) was prepared.

[0060] Separately, a toluene solution (solid content concentration 50% by weight) of YS Resin TO-125 (Yasuhara Chemical Co., Ltd., aromatic modified terpene resin), a terpene resin, was prepared.

[0061] Next, a toluene solution of myristoylated β-1,3-glucan and a toluene solution of YS resin TO-125 were mixed and stirred so that the ratio of YS resin TO-125 to 100 parts by weight of myristoylated β-1,3-glucan was 30 parts by weight. This yielded a toluene solution of the adhesive composition.

[0062] A toluene solution of the adhesive composition was applied to the surface of a polyester substrate (Toray Industries, Inc.: Lumirror S-10, 25 μm thick) as the base sheet 2, using an applicator (Tester Industries Co., Ltd.), and dried at 50°C for 5 minutes and then at 120°C for 5 minutes. This produced an adhesive tape 1 comprising the base sheet 2 and an adhesive layer 3 with a thickness of 50 μm.

[0063] [Examples 2-4, Comparative Example 1 and Comparative Example 2] The adhesive composition and adhesive tape 1 were manufactured in the same manner as in Example 1. However, the type of tackifier was changed as follows. The changes are also shown in Table 1.

[0064] In Example 2, YS Polystar T-130 (Yasuhara Chemical Co., Ltd., phenol-modified terpene resin) was used instead of YS Resin TO-125 (aromatic-modified terpene resin).

[0065] In Example 3, YS Resin PX-1250 (Yasuhara Chemical Co., Ltd., terpene resin) was used instead of YS Resin TO-125 (aromatic modified terpene resin).

[0066] In Example 4, YS Resin P-130 (Yasuhara Chemical Co., Ltd., terpene resin hydride) was used instead of YS Resin TO-125 (aromatic modified terpene resin).

[0067] In Comparative Example 1, Super Ester A-125 (Arakawa Chemical Industries, Ltd., rosin-based resin) was used instead of YS Resin TO-125 (aromatic modified terpene resin).

[0068] In Comparative Example 2, Alcon M-135 (Arakawa Chemical Industries, Ltd., petroleum-based resin) was used instead of YS Resin TO-125 (aromatic modified terpene resin).

[0069] [Examples 7. Comparative Examples 3 to 6 ] The adhesive composition and adhesive tape 1 were prepared in the same manner as in Example 3. However, the type of carbon atoms in the R (aliphatic hydrocarbon group) of the acyl (RCO) introduced into the β-1,3-glucan derivative was changed as follows. The changes are also shown in Table 2.

[0070] comparison example 3 Therefore, instead of myristoylated β-1,3-glucan (where the R (aliphatic hydrocarbon group) in RCO has 13 carbon atoms), we used butanoylated β-1,3-glucan (where the R (aliphatic hydrocarbon group) in RCO has 3 carbon atoms).

[0071] comparison example 4 Therefore, instead of myristoylated β-1,3-glucan (where the R (aliphatic hydrocarbon group) in RCO has 13 carbon atoms), we used octanoylated β-1,3-glucan (where the R (aliphatic hydrocarbon group) in RCO has 7 carbon atoms).

[0072] In Example 7, lauroylated β-1,3-glucan (with 11 carbon atoms in the aliphatic hydrocarbon group R in RCO) was used instead of myristoylated β-1,3-glucan (with 13 carbon atoms in the R (aliphatic hydrocarbon group) in RCO).

[0073] comparison example 5 Therefore, instead of myristoylated β-1,3-glucan (where the R (aliphatic hydrocarbon group) in RCO has 13 carbon atoms), palmitoylated β-1,3-glucan (where the R (aliphatic hydrocarbon group) in RCO has 15 carbon atoms) was used.

[0074] comparison example 6 Therefore, instead of myristoylated β-1,3-glucan (where the R (aliphatic hydrocarbon group) in RCO has 13 carbon atoms), oleoylated β-1,3-glucan (where the R (aliphatic hydrocarbon group) in RCO has 17 carbon atoms) was used.

[0075] [Examples 11-14 and Comparative Examples] 7 ~Comparative Example 9] The adhesive composition and adhesive tape 1 were prepared in the same manner as in Example 3. However, the amount of YS resin PX-1250 per 100 parts by weight of myristoylated β-1,3-glucan was changed as follows. The changes are also shown in Table 3.

[0076] Comparative Example 7 Therefore, the ratio of YS resin PX-1250 to 100 parts by weight of myristoylated β-1,3-glucan was changed from 30 parts by weight to 5 parts by weight.

[0077] In Example 11, the amount of YS resin PX-1250 per 100 parts by weight of myristoylated β-1,3-glucan was changed from 30 parts by weight to 10 parts by weight.

[0078] In Example 12, the amount of YS resin PX-1250 per 100 parts by weight of myristoylated β-1,3-glucan was changed from 30 parts by weight to 50 parts by weight.

[0079] In Example 13, the amount of YS resin PX-1250 per 100 parts by weight of myristoylated β-1,3-glucan was changed from 30 parts by weight to 70 parts by weight.

[0080] In Example 14, the amount of YS resin PX-1250 per 100 parts by weight of myristoylated β-1,3-glucan was changed from 30 parts by weight to 90 parts by weight.

[0081] Comparative Example 8 Therefore, the ratio of YS resin PX-1250 to 100 parts by weight of myristoylated β-1,3-glucan was changed from 30 parts by weight to 120 parts by weight.

[0082] Comparative Example 9 Therefore, the ratio of YS resin PX-1250 to 100 parts by weight of myristoylated β-1,3-glucan was changed from 30 parts by weight to 150 parts by weight.

[0083] [evaluation] The adhesive layers of each example and comparative example were evaluated as follows. The results are shown in Tables 1 to 3. Note that Example 3 is included in all three Tables 1 to 3 for easy comparison with the other examples.

[0084] [Adhesive strength] A sample was prepared by cutting adhesive tape 1 to a size of 20 mm in width and 70 mm in length.

[0085] The adhesive layer 3 of the sample was pressed onto a stainless steel plate by moving a 2kg roller back and forth under conditions of 23°C and 50%RH. It was then left to stand under the same conditions for 30 minutes. Afterward, the peel force (N / 20mm) was measured using a precision universal testing machine, Autograph AG-IS (Shimadzu Corporation), at a peel speed of 300mm / min and a peel angle of 180°. The "adhesion strength" was then obtained. The adhesion strength was measured under conditions of 23°C and 50%RH.

[0086] [Hayes] Adhesive tape 1 was cut to a size of 50 mm wide x 50 mm long to prepare the sample.

[0087] The haze value (H1) of the samples was measured using a "Haze Meter HM150" manufactured by Murakami Color Technology Laboratory Co., Ltd., in accordance with JIS K 7136:2000.

[0088] Separately, only the base sheet 2 was cut to a size of 50 mm x 50 mm, and the haze value (H2) was measured using the same method as described above.

[0089] Subsequently, the haze value (H3) of the adhesive layer 3 was determined using the following formula. H3 = H1 - H2

[0090] [Table 1]

[0091] [Table 2]

[0092] [Table 3]

[0093] The above invention is provided as an illustrative embodiment of the present invention, but this is merely illustrative and should not be interpreted restrictively. Modifications of the present invention that are obvious to those skilled in the art are included in the claims below. [Industrial applicability]

[0094] The adhesive composition is used as a material for the adhesive layer of adhesive tape. [Explanation of Symbols]

[0095] 1 Adhesive tape 3. Adhesive layer

Claims

1. β-1,3-glucan derivatives obtained by introducing an acyl group into β-1,3-glucan, It contains terpene resins, The amount of the terpene resin relative to 100 parts by weight of the β-1,3-glucan derivative is 10 parts by weight or more and 100 parts by weight or less. The aforementioned acyl group is represented by RCO-, An adhesive composition in which R is an aliphatic hydrocarbon group having 8 or more carbon atoms and 14 or fewer carbon atoms.

2. The adhesive composition according to claim 1, wherein the terpene resin is at least one selected from the group consisting of terpene resins, terpene resin hydrides, and phenol-modified terpene resins.

3. An adhesive tape comprising an adhesive layer made of the adhesive composition according to any one of claims 1 or 2.

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