Adhesive composition and adhesive tape

Abstract

An adhesive composition includes a beta-1,3-glucan derivative having an acyl group introduced in a beta-1,3-glucan, and a terpene-based resin. An adhesive tape (1) is provided with an adhesive layer (3) formed of 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 with acyl groups introduced into β-1,3-glucan are known (see, for example, Patent Document 1 below). β-1,3-glucan derivatives are biologically derived polysaccharides, therefore the adhesive described in Patent Document 1 has a lower environmental impact compared to conventional petroleum-based adhesives.

[0003] Existing technical documents

[0004] Patent documents

[0005] Patent Document 1: Japanese Patent Application Publication No. 2018-154723 Summary of the Invention

[0006] The problem the invention aims to solve

[0007] Adhesive compositions used in optical applications and other applications requiring transparency require higher adhesive strength, while simultaneously demanding excellent transparency from the adhesive composition.

[0008] However, the adhesive composition described in Patent Document 1 has the drawback of failing to meet the above requirements.

[0009] This invention provides adhesive compositions and adhesive tapes with high adhesion and excellent transparency.

[0010] Solution for solving the problem

[0011] The present invention (1) comprises an adhesive composition comprising a β-1,3-glucan derivative having an acyl group introduced into β-1,3-glucan, and a terpene resin.

[0012] The present invention (2) comprises the adhesive composition of (1), wherein the terpene resin is at least one selected from the group consisting of terpene resins, hydrides of terpene resins and phenol-modified terpene resins.

[0013] The present invention (3) comprises the adhesive composition described in (1) or (2), wherein the acyl group is represented by RCO-, and the R is an aliphatic hydrocarbon group having 8 or more and 14 or fewer carbon atoms.

[0014] The present invention (4) comprises the adhesive composition of any one of (1) to (3), wherein, relative to 100 parts by weight of the β-1,3-glucan derivative, the terpene resin is 10 parts by weight or more and 100 parts by weight or less.

[0015] The present invention (5) includes an adhesive tape having an adhesive layer formed from any one of the adhesive compositions (1) to (4).

[0016] The effects of the invention

[0017] The adhesive composition and adhesive tape of the present invention have high adhesive strength and excellent transparency. Attached Figure Description

[0018] Figure 1 This is a cross-sectional view of one embodiment of the adhesive tape of the present invention.

[0019] Figure 2 This is a cross-sectional view of another embodiment of the adhesive tape.

[0020] Figure 3 This is a cross-sectional view of another embodiment of the adhesive tape. Detailed Implementation

[0021] [Adhesive Composition]

[0022] The adhesive composition of the present invention comprises a β-1,3-glucan derivative and a terpene resin.

[0023] [β-1,3-glucan derivatives]

[0024] β-1,3-glucan derivatives are the basic polymers in adhesive compositions. β-1,3-glucan derivatives are partially acylated compounds in which a portion of the hydroxyl groups in the glucose contained in β-1,3-glucan are acylated compounds with acyl groups introduced into β-1,3-glucan.

[0025] The acyl group is represented by RCO-. Examples of R include hydrocarbon groups. Examples of hydrocarbon groups include aliphatic hydrocarbon groups, alicyclic hydrocarbon groups, and aromatic hydrocarbon groups, with aliphatic hydrocarbon groups being the most preferred.

[0026] Examples of aliphatic hydrocarbon groups include saturated and unsaturated aliphatic hydrocarbon groups, with saturated aliphatic hydrocarbon groups, i.e., alkyl groups, being preferred. Examples of alkyl groups include straight-chain and branched alkyl groups, with straight-chain alkyl groups being preferred. The number of carbon atoms in the alkyl group is, for example, 3 or more, and also, for example, 18 or less. Examples of straight-chain alkyl groups include propyl, butyl, pentyl, hexyl, heptyl, octyl, nonyl, decyl, undecyl, dodecyl, tridecyl, tetradecyl, pentadecyl, hexadecyl, heptadecanyl, and octadecyl. Examples of unsaturated aliphatic hydrocarbon groups include alkenyl groups, for example, having 3 or more carbon atoms, preferably 5 or more, and also, for example, 18 or less. Examples of alkenyl groups include heptadecanyl.

[0027] The aliphatic hydrocarbon group (alkyl or alkenyl) preferably has 6 or more carbon atoms, more preferably 8 or more, and more preferably 14 or less. If the number of carbon atoms in the aliphatic hydrocarbon group is at or above the lower limit mentioned above, the adhesive strength can be sufficiently improved. If the number of carbon atoms in the aliphatic hydrocarbon group is at or below the upper limit mentioned above, excellent transparency can be achieved while simultaneously improving the adhesive strength.

[0028] Specific examples of acyl groups include butyryl (where R in RCO is C3H7), pentanoyl (where R in RCO is C4H9), and hexanoyl (where R in RCO is C5H9). 11 Examples), heptanyl (R in RCO is C6H) 13 Examples), octanoyl (R in RCO is C7H) 15 Examples), nonanoyl (R in RCO is C8H) 17 Examples), decanoyl (R in RCO is C9H) 19 Examples), lauroyl (i.e., dodecanoyl) (R in RCO is C 11 H 23 Examples), myristoyl (i.e., tetradecanoyl) (R in RCO is C 13 H 27 Examples), palmitoyl (i.e., hexadecanoyl) (R in RCO is C 15 H 31 Examples), stearoyl (i.e., octadecanoyl) (R in RCO is C 17 H 35 Examples), oleoyl group (R in RCO is C) 17 H 33 Examples), and nonadecanyl (R in RCO is C). 18 H 37 Examples include octanoyl, nonanoyl, decanoyl, lauroyl, myristoyl, and palmitoyl.

[0029] The types, properties and manufacturing methods of β-1,3-glucan derivatives are described, for example, in Japanese Patent Application Publication No. 2018-154723.

[0030] The proportion of β-1,3-glucan derivative in the solid component of the adhesive composition is, for example, 50% by weight or more, preferably 60% by weight or more, more preferably 70% by weight or more, and also, for example, 99% by weight or less, preferably 90% by weight or less, more preferably 80% by weight or less.

[0031] β-1,3-glucan derivatives via 1Identification was performed using H-NMR and FT-IR spectroscopy. Detailed identification information is described in Japanese Patent Application Publication No. 2018-154723.

[0032] [Terpene-based resins]

[0033] Terpene resins are used as tackifiers. That is, terpene resins are components that improve the adhesive strength of the adhesive composition. The adhesive composition of the present invention contains terpene resins as tackifiers. Terpene resins can improve the adhesive strength of the adhesive composition while suppressing a decrease in transparency.

[0034] Examples of terpene-based resins include terpene resins, hydrides of terpene resins, aromatic modified terpene resins, phenol-modified terpene resins, and hydrides of phenol-modified terpene resins. They can be used alone or in combination.

[0035] From the viewpoint of further improving adhesion and transparency, at least one type of terpene resin selected from the group consisting of terpene resin, hydride of terpene resin, and phenol-modified terpene resin is preferably included as a terpene resin. Phenolic-modified terpene resin, terpene resin, or hydride of terpene resin is more preferably included as a terpene resin, and terpene resin is even more preferably included. It should be noted that phenol-modified terpene resin is sometimes referred to as terpenephenol resin.

[0036] Furthermore, from the viewpoint of maximizing the proportion of recyclable resources, terpene resins and hydrogenated terpene resins are 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.

[0037] Relative to 100 parts by weight of the β-1,3-glucan derivative, the terpene resin is, for example, 5 parts by weight or more, preferably 10 parts by weight or more, and further, 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. As long as the weight of the terpene resin is above the lower limit mentioned above relative to 100 parts by weight of the β-1,3-glucan derivative, the viscosity increase of the adhesive composition solution (described later) can be suppressed, thereby suppressing poor appearance of the adhesive layer (described later). As long as the weight of the terpene resin is below the upper limit mentioned above relative to 100 parts by weight of the β-1,3-glucan derivative, the exudation of the terpene resin from the adhesive layer under high temperature conditions can be suppressed, thereby further improving adhesion and transparency.

[0038] As a terpene resin, commercially available products can be used.

[0039] Terpene resins in adhesive compositions via1 Identification was performed using 1H-NMR spectroscopy, FT-IR spectroscopy, gel permeation chromatography, and / or mass spectrometry.

[0040] [additive]

[0041] The adhesive composition may contain additives in appropriate proportions. Examples of additives include, for instance, other base polymers (acrylic resins), other tackifiers (rosin-based and petroleum-based resins), viscosity modifiers, leveling agents, plasticizers, fillers, stabilizers, preservatives, and anti-aging agents.

[0042] In manufacturing the adhesive composition, β-1,3-glucan derivatives, terpene resins, and additives as needed are mixed. Alternatively, the above-mentioned components can be dissolved in an organic solvent to prepare a solution containing the adhesive composition. The solution is sometimes referred to as a "solution of the adhesive composition." Examples of organic solvents include low-polarity solvents and high-polarity solvents.

[0043] Examples of low-polarity solvents include aromatic compounds, alicyclic compounds, and saturated chain hydrocarbons. Examples of aromatic compounds include toluene. Examples of alicyclic compounds include cyclohexane and methylcyclohexane. Examples of saturated chain hydrocarbons include pentane, hexane, and heptane.

[0044] Examples of highly polar solvents include ketones, esters, and alcohols. Examples of ketones include methyl ethyl ketone. Examples of esters include ethyl acetate. Examples of alcohols include methanol and ethanol.

[0045] These organic solvents can be used alone or in combination. Preferred examples include the use of low-polarity solvents alone, and the use of low-polarity solvents and high-polarity solvents in combination.

[0046] An aqueous dispersion containing the binder composition can also be prepared by dispersing β-1,3-glucan derivatives and terpene resins in water using emulsifiers and / or dispersants. It should be noted that the aqueous dispersion is sometimes referred to as an "aqueous dispersion of the binder composition".

[0047] The proportion of solid components in the solution or 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.

[0048] Alternatively, a mixing machine or similar device can be used to mix β-1,3-glucan derivatives and terpene resins to prepare a hot melt resin for the adhesive composition. It should be noted that the hot melt resin of the adhesive composition is sometimes simply referred to as "hot melt resin".

[0049] like Figure 1 As shown, a solution of the adhesive composition or an aqueous dispersion of the adhesive composition is coated onto the surface of the substrate sheet 2, and then dried by heating to form the adhesive layer 3. Alternatively, the aforementioned hot-melt resin is hot-melted and coated onto the surface of the substrate sheet 2, and then cooled to form the adhesive layer 3. This allows the manufacture of an adhesive tape 1 having a substrate sheet 2 and an adhesive layer 3.

[0050] For example, resin can be used as the material for the substrate sheet 2. Polyester can be used as an example of resin. The thickness of the substrate sheet 2 is 0.5 μm or more, and, for example, 900 μm or less.

[0051] The thickness of the adhesive layer 3 is, for example, 1 μm or more, and also, for example, 1000 μm or less. The thickness of the adhesive tape 1 is, for example, 2 μm or more, and also, for example, 1100 μm or less.

[0052] Furthermore, such as Figure 2 As shown, the adhesive tape 1 may also have a substrate sheet 2 and an adhesive layer 3 disposed on its surface and back respectively.

[0053] Or, such as Figure 3 As shown, a substrate-free adhesive tape 1 can also be obtained that does not use a substrate sheet 2 but only has an adhesive layer 3. The adhesive tape 1 consists only of the adhesive layer 3.

[0054] [Adhesive strength]

[0055] The adhesive layer 3 at 23°C and 50% RH exhibits an adhesion strength of at least 1 N / 20 mm to the stainless steel sheet, preferably at least 2 N / 20 mm, more preferably at least 3 N / 20 mm, and, for example, at least 20 N / 20 mm. The method for measuring the adhesion strength of the adhesive layer 3 to the stainless steel sheet is described in detail in the following examples.

[0056] The haze of the adhesive layer 3 is, for example, 20% or less, preferably 10% or less, more preferably 5.0% or less, further 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 is described in detail in the following examples. Low haze indicates excellent transparency. When the haze of the adhesive layer 3 is below the aforementioned upper limit, it is suitable for optical applications. Optical applications include, for example, transparent protective films.

[0057] [Effects of adhesive compositions and adhesive tapes]

[0058] This adhesive composition contains terpene resins as an essential tackifier. Therefore, the adhesive composition and tape exhibit high adhesion and excellent transparency. Consequently, the adhesive composition and tape are suitable for optical applications involving transparent protective films.

[0059] In contrast, when the adhesive composition contains rosin-based resins as an essential tackifier, the haze increases, resulting in decreased transparency. Furthermore, when the adhesive composition contains petroleum-based resins as an essential tackifier, the adhesion is not sufficiently improved, leading to increased haze and decreased transparency.

[0060] [Example of a modified adhesive tape]

[0061] In the variations, the same reference numerals are used to mark the same components and processes as in the first embodiment, and detailed descriptions are omitted. Furthermore, unless otherwise specified, the variations can achieve the same effects as the first embodiment. Moreover, it is possible to appropriately combine an embodiment and its variations.

[0062] like Figure 1 Imaginary lines and Figure 2 As shown by the imaginary line, the modified adhesive tape 1 also has a release tab 4 disposed on the surface of the adhesive layer 3.

[0063] Example

[0064] The specific values ​​of mixing ratios (including proportions), physical property values, parameters, etc. used in the following description can replace the corresponding upper limit values ​​(defined as "less" or "less than") or lower limit values ​​(defined as "more than" or "exceeding") of the mixing ratios (including proportions), physical property values, parameters, etc., described in the "Specific Embodiments" above. Furthermore, in the following description, unless otherwise specified, "parts" and "%" are based on weight.

[0065] [Examples of the synthesis of β-1,3-glucan derivatives]

[0066] Synthesis example 1

[0067] Synthesis of myristylated β-1,3-glucan (R in RCO has 13 carbon atoms in the aliphatic hydrocarbon group)

[0068] 13.3 g of β-1,3-glucan (Euglena Co Ltd: 82.03 mmol of glucose fraction) and 1000 mL of dehydrated pyridine (Fujifilm and Kazumitsu Chemical Co., Ltd.) were added to a reaction vessel equipped with a cooling pipe, a nitrogen inlet pipe, a thermometer, and a stirrer. The mixture was stirred at 92°C under a nitrogen atmosphere for 0.5 hours. Then, 133.05 mL of myristoyl chloride (492.2 mmol: Fujifilm and Kazumitsu Chemical 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.

[0069] Then, a solid intermediate was obtained from the reaction mixture. First, one hour after the start of the reaction, 2000 mL of methanol was added to the reaction mixture, and the mixture was cooled to room temperature. The resulting solid was then removed and dissolved in 600 mL of toluene to prepare a toluene solution. The toluene solution was then injected into 2000 mL of stirred methanol to obtain a solid. The solid was washed by repeating the process of dissolving the solid in toluene and injecting it into methanol three times to obtain another solid. The solid was then dried under reduced pressure at 60 °C for 4 hours. This yielded myristylated β-1,3-glucan. In other words, myristylated β-1,3-glucan is a β-1,3-glucan derivative incorporating a myristoyl group into β-1,3-glucan.

[0070] Synthesis example 2

[0071] [Synthesis of palmitoylated β-1,3-glucan (R in RCO has 15 carbon atoms in the aliphatic hydrocarbon group)]

[0072] Palmitoylated β-1,3-glucan was obtained by proceeding with the same treatment as in Synthesis Example 1. However, the amount of myristoyl chloride (133.05 mL, 492.2 mmol) was replaced with palmitoyl chloride (150.21 mL, 492.2 mmol: Fujifilm and Koichi Pure Chemicals Co., Ltd.). In other words, palmitoylated β-1,3-glucan is a β-1,3-glucan derivative incorporating a palmitoyl group into β-1,3-glucan.

[0073] Synthesis example 3

[0074] Synthesis of lauroyl β-1,3-glucan (R in RCO has 11 carbon atoms in the aliphatic hydrocarbon group)

[0075] Lauroylated β-1,3-glucan was obtained by proceeding with the same treatment as in Synthesis Example 1. However, the amount of myristoyl chloride (133.05 mL, 492.2 mmol) was replaced with lauroyl chloride (113.81 mL, 492.2 mmol: Fujifilm Wōko Co., Ltd.). In other words, lauroylated β-1,3-glucan is a β-1,3-glucan derivative incorporating a lauroyl group into β-1,3-glucan.

[0076] Synthesis example 4

[0077] Synthesis of octanoyl β-1,3-glucan (R in RCO has 7 carbon atoms in the aliphatic hydrocarbon group)]

[0078] The same procedure as in Synthesis Example 1 was followed to obtain octanoyl β-1,3-glucan. However, the myristoyl chloride (133.05 mL, 492.2 mmol) was replaced with octanoyl chloride (84.18 mL, 492.2 mmol: Fujifilm Wōko Co., Ltd.). In other words, octanoyl β-1,3-glucan is a β-1,3-glucan derivative incorporating an octanoyl group into β-1,3-glucan.

[0079] Synthesis example 5

[0080] [Synthesis of butyrylated β-1,3-glucan (R in RCO has 3 carbon atoms in the aliphatic hydrocarbon group)]

[0081] Butyrylated β-1,3-glucan was obtained by proceeding with the same treatment as in Synthesis Example 1. However, the myristoyl chloride (133.05 mL, 492.2 mmol) was replaced with butyryl chloride (50.98 mL, 492.2 mmol: Fujifilm Wōko Co., Ltd.). In other words, butyrylated β-1,3-glucan is a β-1,3-glucan derivative incorporating a butyryl group into β-1,3-glucan.

[0082] Synthesis example 6

[0083] Synthesis of oleylamide β-1,3-glucan (R in RCO has 17 carbon atoms in the aliphatic hydrocarbon group)]

[0084] The same procedure as in Synthesis Example 1 was followed to obtain oleylated β-1,3-glucan. However, the myristoyl chloride 133.05 mL (492.2 mmol) was replaced with oleoyl chloride 162.38 mL (492.2 mmol: Fujifilm Wōko Co., Ltd.). In other words, oleylated β-1,3-glucan is a β-1,3-glucan derivative incorporating an oleyl group into β-1,3-glucan.

[0085] [Manufacturing of Adhesive Tape]

[0086] [Example 1]

[0087] Prepare a toluene solution of myristylated β-1,3-glucan (solid content concentration 10% by weight).

[0088] In addition, a toluene solution (solid content concentration 50% by weight) was prepared for YS resin TO-125 (YASUHARA CHEMICAL CO.,LTD., aromatic modified terpene resin), which is a terpene resin.

[0089] Next, a toluene solution of myristoylated β-1,3-glucan and a toluene solution of YS resin TO-125 were mixed and stirred, with the ratio of YS resin TO-125 parts by weight to myristoylated β-1,3-glucan parts by weight being 30 parts by weight. This yielded a toluene solution of the adhesive composition.

[0090] As the substrate sheet 2, a toluene solution of the adhesive composition is applied to the surface of a polyester substrate (Toray Industries, Inc. Lumirror S-10, 25 μm thick) using a spreader (TESTER SANGYO CO,.LTD.), dried at 50°C for 5 minutes, and further dried at 120°C for 5 minutes. Thus, an adhesive tape 1 having the substrate sheet 2 and an adhesive layer 3 with a thickness of 50 μm is manufactured.

[0091] [Examples 2-4, Comparative Example 1 and Comparative Example 2]

[0092] 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 shown below. The changes are also shown in Table 1.

[0093] In Example 2, YS Polyster T-130 (YASUHARA CHEMICAL CO.,LTD., phenol-modified terpene resin) was used instead of YS resin TO-125 (aromatic modified terpene resin).

[0094] 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).

[0095] In Example 4, YS resin P-130 (YASUHARA CHEMICAL CO.,LTD., a hydrogenated terpene resin) was used instead of YS resin TO-125 (aromatic modified terpene resin).

[0096] In Comparative Example 1, Super Ester A-125 (Arakawa Chemical Industry Co., Ltd., rosin-based resin) was used instead of YS resin TO-125 (aromatic modified terpene resin).

[0097] In Comparative Example 2, Arkon M-135 (Arakawa Chemical Industry Co., Ltd., petroleum-based resin) was used instead of YS resin TO-125 (aromatic modified terpene resin).

[0098] [Examples 5 to 9]

[0099] The adhesive composition and adhesive tape 1 were manufactured in the same manner as in Example 3. However, the type of carbon atom number of the R (aliphatic hydrocarbon group) in the acyl group (RCO) introduced into the β-1,3-glucan derivative was changed as shown below. The changes are also shown in Table 2.

[0100] In Example 5, butyrylated β-1,3-glucan (R in RCO has 3 carbon atoms) was used instead of myristylated β-1,3-glucan (R in RCO has 13 carbon atoms).

[0101] In Example 6, octanoyl β-1,3-glucan (R in RCO has 7 carbon atoms) was used instead of myristoylated β-1,3-glucan (R in RCO has 13 carbon atoms).

[0102] In Example 7, lauroyl β-1,3-glucan (R in RCO has 11 carbon atoms in the aliphatic hydrocarbon group) was used instead of myristyl β-1,3-glucan (R in RCO has 13 carbon atoms in the aliphatic hydrocarbon group).

[0103] In Example 8, palmitoylated β-1,3-glucan (R in RCO has 15 carbon atoms) was used instead of myristoylated β-1,3-glucan (R in RCO has 13 carbon atoms).

[0104] In Example 9, oleyl β-1,3-glucan (R in RCO has 17 carbon atoms) was used instead of myristyl β-1,3-glucan (R in RCO has 13 carbon atoms).

[0105] [Examples 10 to 16]

[0106] The adhesive composition and adhesive tape 1 were manufactured in the same manner as in Example 3. However, the weight parts of YS resin PX-1250 relative to 100 parts by weight of myristylated β-1,3-glucan were changed as shown below. The changes are also shown in Table 3.

[0107] In Example 10, the weight of YS resin PX-1250 relative to 100 parts by weight of myristylated β-1,3-glucan was changed from 30 parts by weight to 5 parts by weight.

[0108] In Example 11, the weight of YS resin PX-1250 relative to 100 parts by weight of myristylated β-1,3-glucan was changed from 30 parts by weight to 10 parts by weight.

[0109] In Example 12, the weight of YS resin PX-1250 relative to 100 parts by weight of myristylated β-1,3-glucan was changed from 30 parts by weight to 50 parts by weight.

[0110] In Example 13, the weight of YS resin PX-1250 relative to 100 parts by weight of myristylated β-1,3-glucan was changed from 30 parts by weight to 70 parts by weight.

[0111] In Example 14, the weight of YS resin PX-1250 relative to 100 parts by weight of myristylated β-1,3-glucan was changed from 30 parts by weight to 90 parts by weight.

[0112] In Example 15, the weight of YS resin PX-1250 relative to 100 parts by weight of myristylated β-1,3-glucan was changed from 30 parts by weight to 120 parts by weight.

[0113] In Example 16, the weight of YS resin PX-1250 relative to 100 parts by weight of myristylated β-1,3-glucan was changed from 30 parts by weight to 150 parts by weight.

[0114] [evaluate]

[0115] The adhesive layers of each embodiment and comparative example were evaluated for the following aspects. These results are shown in Tables 1 to 3. It should be noted that Example 3 is included in all Tables 1 to 3 for easy comparison with other embodiments.

[0116] [Adhesive strength]

[0117] Cut adhesive tape 1 into pieces 20mm wide and 70mm long to make a sample.

[0118] The adhesive layer 3 of the sample was pressed onto a stainless steel plate by reciprocating a 2 kg roller at 23°C and 50% RH. It was then left in this environment for 30 minutes. The peel force (N / 20 mm) at a peel speed of 300 mm / min and a peel angle of 180° was then measured using an Autograph AG-IS precision universal testing machine (Shimadzu Corporation), yielding the "adhesive force". The adhesive force was measured at 23°C and 50% RH.

[0119] [Haze]

[0120] Cut the adhesive tape 1 into 50mm wide x 50mm long pieces to prepare samples.

[0121] The haze value (H1) of the sample was measured using a "HM150 haze meter" manufactured by Murakami Color Technology Research Institute Co., Ltd., in accordance with JIS K 7136:2000.

[0122] In addition, the substrate sheet 2 was cut into 50mm×50mm pieces, and the haze value (H2) was measured using the same method as described above.

[0123] Then, the haze value (H3) of the adhesive layer 3 is calculated using the following formula.

[0124] H3 = H1 - H2

[0125] [Table 1]

[0126]

[0127] [Table 2]

[0128]

[0129] [Table 3]

[0130]

[0131] It should be noted that the above technical solutions are provided as illustrative embodiments of the present invention, but these are merely illustrative and not limiting. Variations of the present invention that will be apparent to those skilled in the art are included within the scope of the claims.

[0132] Industrial availability

[0133] The adhesive composition is used as a material for the adhesive layer of an adhesive tape.

[0134] Explanation of reference numerals in the attached figures

[0135] 1. Adhesive tape

[0136] 3 Adhesive layer

Claims

1. An adhesive composition comprising: β-1,3-glucan derivatives with acyl groups introduced into β-1,3-glucan, and Terpene resins in, Relative to 100 parts by weight of the β-1,3-glucan derivative, the terpene resin comprises 10 parts by weight or more and 90 parts by weight or less. The acyl group is represented by RCO-. The R is an aliphatic hydrocarbon group with 7 or more but less than 15 carbon atoms.

2. The adhesive composition according to claim 1, wherein, The terpene resin is selected from at least one of the following groups: terpene resin, hydride of terpene resin, and phenol-modified terpene resin.

3. The adhesive composition according to claim 1 or 2, wherein, The acyl group is represented by RCO-. The R is an aliphatic hydrocarbon group with 8 or more but less than 14 carbon atoms.

4. An adhesive tape comprising an adhesive layer formed of the adhesive composition according to any one of claims 1 to 3.

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