Adhesive composition and adhesive tape

Abstract

To provide an adhesive composition and an adhesive tape having a high adhesive force as well as a high holding force in a high temperature atmosphere.SOLUTION: The adhesive composition contains a β-1,3-glucan derivative with a substitution degree of an acyl group of 2.6 to less than 3.0, and an isocyanate-based cross-linking agent. The adhesive tape includes an adhesive layer composed of the adhesive composition.SELECTED DRAWING: None

Description

[Technical field]

[0001] The present invention relates to a pressure-sensitive adhesive composition and a pressure-sensitive adhesive tape. [Background technology]

[0002] An adhesive composition containing a β-1,3-glucan derivative in which an acyl group has been introduced into a β-1,3-glucan is known (see, for example, Patent Document 1 below). The adhesive described in Patent Document 1 contains a β-1,3-glucan derivative with an acyl group substitution degree of 2.5. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2018-154723 A Summary of the Invention [Problem to be solved by the invention]

[0004] In recent years, there has been a demand for a higher level of adhesive strength, but the adhesive composition described in Patent Document 1 has the disadvantage of being unable to satisfy the above-mentioned requirements.

[0005] Furthermore, the adhesive composition is required to have a high holding power in a high-temperature atmosphere. When the holding power in a high-temperature atmosphere is high, the distance by which the adherend is displaced after a predetermined time has elapsed after the adherend is adhered in a high-temperature atmosphere is short. The adhesive composition described in Patent Document 1 has a problem in that it cannot satisfy the above requirements.

[0006] The present invention provides a pressure-sensitive adhesive composition and a pressure-sensitive adhesive tape that have high adhesive strength and high holding power even in a high-temperature atmosphere. [Means for solving the problem]

[0007] The present invention (1) includes a pressure-sensitive adhesive composition comprising a β-1,3-glucan derivative in which an acyl group has been introduced into β-1,3-glucan, the β-1,3-glucan having a substitution degree of the acyl group of 2.6 or more and less than 3.0, and an isocyanate-based crosslinking agent.

[0008] The present invention (2) includes the pressure-sensitive adhesive composition according to (1), in which the isocyanate-based crosslinking agent is at least one selected from the group consisting of an adduct-type isocyanate-based crosslinking agent, an isocyanurate-type isocyanate-based crosslinking agent, and an allophanate-type isocyanate-based crosslinking agent.

[0009] The present invention (3) also includes the adhesive composition according to (1) or (2), in which the number of parts by weight of the isocyanate-based crosslinking agent per 100 parts by weight of the β-1,3-glucan derivative is 0.1 parts by weight or more and 10 parts by weight or less.

[0010] The present invention (4) also includes the pressure-sensitive adhesive composition according to any one of (1) to (3), which comprises a pressure-sensitive adhesive layer made of the pressure-sensitive adhesive composition. Effect of the Invention

[0011] The pressure-sensitive adhesive composition and pressure-sensitive adhesive tape of the present invention have high adhesive strength and also have high holding power in a high-temperature atmosphere. [Brief description of the drawings]

[0012] [Figure 1] FIG. 1 is a cross-sectional view of one embodiment of the pressure-sensitive adhesive tape of the present invention. [Diagram 2] FIG. 2 is a cross-sectional view of another embodiment of the adhesive tape. [Diagram 3] FIG. 3 is a cross-sectional view of another embodiment of the adhesive tape. [Figure 4] FIG. 4 is a schematic diagram showing the measurement of the holding force in the examples. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0013] [Adhesive composition] The pressure-sensitive adhesive composition of the present invention contains a β-1,3-glucan derivative and an isocyanate-based crosslinking agent.

[0014] [β-1,3-glucan derivative] The β-1,3-glucan derivative is a base polymer in the adhesive composition. The β-1,3-glucan derivative is a partially acyl compound in which some of the hydroxyl groups in the glucose contained in the β-1,3-glucan are acylated with an acyl group. In other words, the β-1,3-glucan derivative is an acyl compound in which an acyl group is introduced into the β-1,3-glucan.

[0015] 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 preferably an aliphatic hydrocarbon group.

[0016] Examples of the aliphatic hydrocarbon group include saturated aliphatic hydrocarbon groups and unsaturated aliphatic hydrocarbon groups. Examples of the saturated aliphatic hydrocarbon group include alkyl groups. Examples of the alkyl group include linear alkyl groups and branched alkyl groups, and preferably linear alkyl groups. 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 branched alkyl group include ethylhexyl.

[0017] An example of the unsaturated aliphatic hydrocarbon group is an alkenyl group. The number of carbon atoms in the alkenyl group is, for example, 3 or more and 18 or less. An example of the alkenyl group is heptadecenyl.

[0018] The number of carbon atoms in the hydrocarbon group (R in RCO-) is preferably 7 or more, more preferably 9 or more, even more preferably 11 or more, and preferably not more than 15. When the number of carbon atoms in the hydrocarbon group is not less than the above-mentioned lower limit or not more than the above-mentioned upper limit, the adhesive strength can be sufficiently improved.

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

[0020] In the present invention, the lower limit of the degree of substitution of the acyl group in the β-1,3-glucan derivative is 2.6. If the degree of substitution of the acyl group is less than 2.6, the amount of remaining hydroxyl groups in the β-1,3-glucan derivative will be excessive. In other words, the interaction between the molecular chains of the β-1,3-glucan derivative will be too strong. Therefore, the adhesive composition will harden. As a result, the adhesive strength of the adhesive composition will decrease.

[0021] The degree of substitution of the acyl group can be referred to as DS. The degree of substitution of the acyl group in a β-1,3-glucan derivative is the average number of hydroxyl groups in a β-1,3-glucan unit that are substituted (introduced) with an acyl group. Therefore, theoretically, the upper limit of the degree of substitution of the acyl group in a β-1,3-glucan derivative is 3.0.

[0022] In the present invention, the substitution degree of acyl group in β-1,3-glucan derivative is less than 3.0.On the other hand, if the substitution degree of acyl group in β-1,3-glucan derivative is 3.0, no hydroxyl group remains in β-1,3-glucan derivative, so that no crosslinking point exists in β-1,3-glucan derivative, and then, β-1,3-glucan derivative is not crosslinked by isocyanate-based crosslinking agent.As a result, the holding power of the adhesive composition is reduced.

[0023] The degree of substitution of acyl groups in the β-1,3-glucan derivative is preferably 2.7 or more, or 2.8 or more, and for example, 2.9 or less, preferably 2.8 or less.

[0024] The types, properties and production methods of β-1,3-glucan derivatives are described, for example, in JP 2018-154723 A. The substitution degree of the acyl group in the β-1,3-glucan derivative is: 1 Determined by H-NMR. 1 Measurement by H-NMR is described in, for example, JP 2015-124183 A.

[0025] The proportion of the β-1,3-glucan derivative in the pressure-sensitive adhesive composition is, for example, 80% by weight or more, and, for example, 99.99% by weight or less.

[0026] [Isocyanate-based crosslinking agent] The isocyanate-based crosslinking agent is a crosslinking agent that reacts with the hydroxyl groups in the β-1,3-glucan derivative to crosslink the β-1,3-glucan derivative. On the other hand, pressure-sensitive adhesive compositions containing crosslinking agents other than the isocyanate-based crosslinking agent, such as oxazoline-based crosslinking agents, carbodiimide-based crosslinking agents, and / or epoxy-based crosslinking agents, are unsuitable for the present invention because they reduce the adhesive strength or holding power.

[0027] Examples of the isocyanate crosslinking agent include an adduct type isocyanate crosslinking agent, an isocyanurate type isocyanate crosslinking agent, and an allophanate type isocyanate crosslinking agent.

[0028] Isocyanate crosslinking agents are also classified according to the molecular structure of the raw isocyanate. Specifically, examples of isocyanate crosslinking agents include hexamethylene diisocyanate (HDI) crosslinking agents, tolylene diisocyanate (TDI) crosslinking agents, xylylene diisocyanate (XDI) crosslinking agents, and hydrogenated xylylene diisocyanate (H6XDI) (also known as 1,3-bis(isocyanatomethyl)cyclohexane) crosslinking agents.

[0029] Examples of HDI type crosslinking agents include trimethylolpropane adduct of HDI, isocyanurate of HDI, and allophanate of HDI. Of the HDI type crosslinking agents, isocyanurate of HDI is preferred from the viewpoint of reducing the adhesive composition residue (or contamination of the adherend) of the adhesive composition remaining on the adherend.

[0030] TDI-type crosslinkers include, for example, trimethylolpropane adducts of TDI, isocyanurates of TDI, and allophanates of TDI.

[0031] Examples of XDI-type crosslinking agents include trimethylolpropane adducts of XDI, isocyanurates of XDI, and allophanates of XDI.

[0032] Examples of H6XDI-type crosslinkers include H6XDI, trimethylolpropane adducts of H6XDI, isocyanurates of H6XDI, and allophanates of H6XDI.

[0033] The above-mentioned isocyanate-based crosslinking agents can be used alone or in combination.

[0034] As the isocyanate-based crosslinking agent, from the viewpoint of obtaining high adhesive strength and high holding power, preferable examples thereof include HDI type crosslinking agents, XDI type crosslinking agents and TDI type crosslinking agents.

[0035] The number of parts by weight of the isocyanate crosslinking agent relative to 100 parts by weight of the β-1,3-glucan derivative is, for example, 0.01 parts by weight or more, preferably 0.1 parts by weight or more, more preferably 0.5 parts by weight or more, and even more preferably 1.0 parts by weight or more. If the number of parts by weight of the isocyanate crosslinking agent relative to 100 parts by weight of the β-1,3-glucan derivative is equal to or more than the above-mentioned lower limit, the adhesive composition can have a higher holding power. Furthermore, the adhesive composition residue can be reduced.

[0036] The number of parts by weight of the isocyanate crosslinking agent relative to 100 parts by weight of the β-1,3-glucan derivative is, for example, 20 parts by weight or less, preferably 10 parts by weight or less, more preferably 5.0 parts by weight or less, and even more preferably 3.0 parts by weight or less. If the number of parts by weight of the isocyanate crosslinking agent relative to 100 parts by weight of the β-1,3-glucan derivative is equal to or less than the upper limit described above, the adhesive composition can have a higher adhesive strength. Furthermore, the adhesive composition residue can be reduced.

[0037] As the isocyanate-based crosslinking agent, a commercially available product can be used.

[0038] [Additives] The adhesive composition may contain additives in an appropriate ratio within a range that does not impair the effects of the present application. Examples of additives include other base polymers (acrylic resins), other crosslinking agents (oxazoline, carbodiimide, and epoxy), tackifiers, viscosity modifiers, leveling agents, plasticizers, fillers, stabilizers, preservatives, crosslinking accelerators, and antiaging agents.

[0039] To produce the adhesive composition, a β-1,3-glucan derivative, an isocyanate-based crosslinking agent, and, if necessary, additives are blended and mixed. The above-mentioned components can also be dissolved in a solvent to prepare a solution containing the adhesive composition. The type of solvent is not limited. The solid content of the adhesive composition solution is, for example, 1% by weight or more, preferably 5% by weight or more, and, for example, less than 50% by weight, preferably 30% by weight or less.

[0040] As shown in FIG. 1, the solution of the adhesive composition is applied to the surface of a substrate sheet 2, and then dried to form an adhesive layer 3. When drying, heating is performed as necessary. The drying conditions are not limited as long as the isocyanate groups of the isocyanate crosslinking agent react with the hydroxyl groups of the β-1,3-glucan derivative to crosslink the β-1,3-glucan derivative. For example, the applied solution of the adhesive composition is left at 100° C. for, for example, 5 minutes or more, preferably 15 minutes or more. The upper limit of the leaving time is not limited.

[0041] In this way, the adhesive tape 1 having the base sheet 2 and the adhesive layer 3 can be produced.

[0042] An example of the material of the base sheet 2 is a resin. An example of the resin is a polyester. The thickness of the base sheet 2 is 0.5 μm or more and, for example, 900 μm or less.

[0043] The pressure-sensitive adhesive layer 3 has a thickness of, for example, 1 μm or more and, for example, 1000 μm or less. The pressure-sensitive adhesive tape 1 has a thickness of, for example, 2 μm or more and, for example, 1100 μm or less.

[0044] Furthermore, as shown in FIG. 2, the pressure-sensitive adhesive tape 1 can also include a base sheet 2 and pressure-sensitive adhesive layers 3 disposed on both the front and back surfaces of the base sheet 2.

[0045] 3, it is also possible to obtain a substrate-less adhesive tape 1 that does not use a substrate sheet 2 and that is provided with only an adhesive layer 3. The adhesive tape 1 is made of only the adhesive layer 3.

[0046] [Effects of the adhesive composition and adhesive tape] This adhesive composition contains a β-1,3-glucan derivative having an acyl group substitution degree of 2.6 or more and less than 3.0, and an isocyanate-based crosslinking agent. Then, the isocyanate group of the isocyanate-based crosslinking agent reacts with the hydroxyl group corresponding to the above-mentioned substitution degree of the acyl group, and the β-1,3-glucan derivative is appropriately crosslinked. This makes it possible to form an adhesive layer 3 having excellent adhesive strength and holding power. Furthermore, after the adhesive composition adheres to an adherend and is peeled off from the adherend, the occurrence of adhesive composition residue on the adherend can be reduced.

[0047] [Modification of adhesive tape] In the modified example, the same components and steps as those in the first embodiment are denoted by the same reference numerals, and detailed description thereof will be omitted. In addition, the modified example can achieve the same effects as those in the first embodiment, unless otherwise specified. Furthermore, the first embodiment and its modified example can be appropriately combined.

[0048] As shown by the phantom lines in FIG. 1 and FIG. 2, the pressure-sensitive adhesive tape 1 of the modified example further includes a release sheet 4 disposed on the surface of the pressure-sensitive adhesive layer 3. EXAMPLES

[0049] The present invention will be described in more detail below with reference to synthesis examples, examples, and comparative examples. The present invention is not limited to the synthesis examples, examples, and comparative examples. In addition, the specific numerical values ​​of the blending ratio (content ratio), physical property values, parameters, etc. used in the following description can be replaced with the upper limit value (numeric value defined as "less than or equal to" or "less than") or lower limit value (numeric value defined as "more than or equal to" or "exceeding") of the corresponding blending ratio (content ratio), physical property value, parameter, etc. described in the above "Form for carrying out the invention". In addition, unless otherwise specified in the following description, "parts" and "%" are based on weight.

[0050] [Synthesis of β-1,3-glucan derivatives and measurement of the degree of substitution (DS) of acyl groups] Synthesis Example 1 [Synthesis of myristoylated β-1,3-glucan (RCO has 13 carbon atoms) with an acyl group substitution degree of 2.7, and the degree of myristoyl substitution]

[0051] 13.3 g of β-1,3-glucan (Euglena strain: glucose portion is 82.0 mmol) and 1000 mL of dehydrated pyridine (Fujifilm Wako Pure Chemical Industries, Ltd.) were added to a reaction vessel equipped with a cooling tube, nitrogen inlet tube, thermometer, and stirrer, and the mixture was stirred for 0.5 hours under a nitrogen atmosphere at a temperature of 60°C. 88.7 mL of myristoyl chloride (328.1 mmol: Fujifilm Wako Co., Ltd.) was added to the pyridine solution, which was then heated to 60°C and stirred for 1 hour. This prepared a reaction mixture.

[0052] After that, a solid intermediate was obtained from the reaction mixture. First, 1 hour after the start of the reaction, 2000 mL of methanol was added to the reaction mixture and cooled to room temperature. Next, the resulting solid was taken out and dissolved in 600 mL of toluene to prepare a toluene solution. The toluene solution was poured into 2000 mL of stirring methanol to obtain a solid. The solid was dissolved in toluene and poured into methanol three times to wash and obtain a solid. The solid was dried under reduced pressure at 60°C for 4 hours.

[0053] In this way, myristoylated β-1,3-glucan was obtained. In other words, myristoylated β-1,3-glucan is a β-1,3-glucan derivative in which myristoyl has been introduced into β-1,3-glucan.

[0054] The degree of substitution of the myristoyl group in the myristoylated β-1,3-glucan was determined as follows: 1 The carbonyl group was determined by H-NMR. 1 In H-NMR, the signals of hydrogen atoms forming the hydroxyl groups in the glucose units and myristoyl (C 13 H 27 The signal of the hydrogen atom forming the β-1,3-glucan derivative (CO) was detected by distinguishing it from the signal of the hydrogen atom forming the β-1,3-glucan derivative (CO). The degree of substitution of the myristoyl group (acyl group) was calculated based on the integral value of each of the two signals. As a result, the degree of substitution (DS) of the acyl group in the β-1,3-glucan derivative in the following synthesis example was also calculated in the same manner as above.

[0055] Synthesis Example 2 [Synthesis of myristoylated β-1,3-glucan (RCO: carbon number of R is 13) with acyl group substitution degree of 2.8] Myristoylated β-1,3-glucan was obtained by treating in the same manner as in Synthesis Example 1. However, the amount of myristoyl chloride was changed from 88.7 mL (328.1 mmol) to 110.9 mL (410.1 mmol). 1 The degree of myristoyl substitution determined by 1 H-NMR was 2.8.

[0056] Synthesis Example 3 [Synthesis of myristoylated β-1,3-glucan (RCO has 13 carbon atoms) with an acyl group substitution degree of 2.9] Myristoylated β-1,3-glucan was obtained by treating in the same manner as in Synthesis Example 1. However, the amount of myristoyl chloride was changed from 88.7 mL (328.1 mmol) to 133.1 mL (492.2 mmol). 1 The degree of myristoyl substitution by H-NMR was 1 H-NMR gave a molecular weight of 2.9.

[0057] Comparative synthesis example 1 [Synthesis of myristoylated β-1,3-glucan (RCO has 13 carbon atoms) with an acyl group substitution degree of 2.5] Myristoylated β-1,3-glucan was obtained by treating in the same manner as in Synthesis Example 1. However, the amount of myristoyl chloride was changed from 88.7 mL (328.1 mmol) to 66.5 mL (246.1 mmol). The degree of substitution of the myristoyl group was 1 H-NMR gave a molecular weight of 2.5.

[0058] Synthesis Example 4 [Synthesis of octanoyl β-1,3-glucan (RCO has 7 carbon atoms) with an acyl group substitution degree of 2.8] An octanoylated β-1,3-glucan having a substitution degree of 2.8 was obtained by treating in the same manner as in Synthesis Example 2. However, 70.0 mL (410.1 mmol) of octanoyl chloride was used in place of myristoyl chloride.

[0059] Synthesis Example 5 [Synthesis of lauroyl β-1,3-glucan (RCO has 11 carbon atoms) with an acyl group substitution degree of 2.8] A lauroyl β-1,3-glucan having a substitution degree of 2.8 was obtained by treating in the same manner as in Synthesis Example 2. However, 94.8 mL (410.1 mmol) of lauroyl chloride was used in place of myristoyl chloride.

[0060] Synthesis Example 6 [Synthesis of palmitoylated β-1,3-glucan (RCO has 15 carbon atoms) with an acyl group substitution degree of 2.8] A palmitoylated β-1,3-glucan having a substitution degree of 2.8 was obtained by treating in the same manner as in Synthesis Example 2. However, 124.4 mL (410.1 mmol) of palmitoyl chloride was used in place of myristoyl chloride.

[0061] The carbon number and degree of substitution (DS) of R in each synthesis example and comparative synthesis example are shown in Table 1.

[0062] [Adhesive tape manufacturing] [Example 1] The myristoylated β-1,3-glucan of Synthesis Example 1 was dissolved in toluene to prepare a toluene solution with a solids concentration of 10% by weight.

[0063] To the prepared toluene solution, Coronate L (trimethylolpropane adduct of tolylene diisocyanate, manufactured by Tosoh Corporation) was added as an isocyanate-based crosslinking agent. The solid content of Coronate L was 1.0 part by weight per 100 parts by weight of the solid content (myristoylated β-1,3-glucan) of the toluene solution. Thus, a toluene solution of the adhesive composition was obtained.

[0064] A toluene solution of the adhesive composition was applied to the surface of a base sheet 2 made of a polyester base material (Toray Industries, Inc.: Lumirror S-10, thickness 25 μm) using an applicator (Tester Sangyo Co., Ltd.), heated at 50° C. for 5 minutes, and further heated at 100° C. for 5 minutes to dry the toluene solution. In this way, an adhesive tape 1 comprising the base sheet 2 and an adhesive layer 3 having a thickness of 50 μm was produced.

[0065] [Examples 2 to 8, 10 to 14, and 18 and Comparative Examples 1 to 8] In Example 2, Example 3, Example 18, Comparative Example 1, Comparative Example 7, and Comparative Example 8, In the same manner as in Example 1 ,So Adhesive Tape 1 was produced for each. However, the composition of the toluene solution of the β-1,3-glucan derivative was changed as follows: In Examples 4 to 8, Examples 10 to 14, and Comparative Examples 2 to 6, pressure-sensitive adhesive tapes 1 were produced in the same manner as in Example 2. However, the toluene solution of the β-1,3-glucan derivative or the composition of the crosslinking agent was changed as follows (Tables 2 to 5 also show the changes).

[0066] [Example 2] Instead of the myristoylated β-1,3-glucan having an acyl substitution degree of 2.7 in Synthesis Example 1, a myristoylated β-1,3-glucan having an acyl substitution degree of 2.8 in Synthesis Example 2 was used. That is, in Example 2, the acyl substitution degree in the β-1,3-glucan derivative was changed to 2.8.

[0067] [Example 3] Instead of the myristoylated β-1,3-glucan having an acyl substitution degree of 2.7 in Synthesis Example 1, a myristoylated β-1,3-glucan having an acyl substitution degree of 2.9 in Synthesis Example 3 was used. That is, in Example 3, the acyl substitution degree in the β-1,3-glucan derivative was changed to 2.9.

[0068] [Comparative Example 1] Instead of the myristoylated β-1,3-glucan having an acyl substitution degree of 2.7 in Synthesis Example 1, a myristoylated β-1,3-glucan having an acyl substitution degree of 2.5 in Comparative Synthesis Example 1 was used. That is, in Comparative Example 1, the acyl substitution degree in the β-1,3-glucan derivative was changed to 2.5.

[0069] [Example 4] Coronate HL (a trimethylolpropane adduct of hexamethylene diisocyanate, manufactured by Tosoh Corporation) was used in place of Coronate L (a trimethylolpropane adduct of tolylene diisocyanate, manufactured by Tosoh Corporation).

[0070] [Example 5] Takenate 110N (a trimethylolpropane adduct of xylylene diisocyanate, manufactured by Mitsui Chemicals) was used in place of Coronate L (a trimethylolpropane adduct of tolylene diisocyanate, manufactured by Tosoh Corporation).

[0071] [Example 6] Takenate 600 (hydrogenated xylylene diisocyanate, manufactured by Mitsui Chemicals) was used in place of Coronate L (a trimethylolpropane adduct of tolylene diisocyanate, manufactured by Tosoh Corporation).

[0072] [Example 7] Coronate HX (isocyanurate of hexamethylene diisocyanate, manufactured by Tosoh Corporation) was used in place of Coronate L (trimethylolpropane adduct of tolylene diisocyanate, manufactured by Tosoh Corporation).

[0073] [Example 8] Duranate A201H (an allophanate of hexamethylene diisocyanate, manufactured by Asahi Kasei Corporation) was used in place of Coronate L (a trimethylolpropane adduct of tolylene diisocyanate, manufactured by Tosoh Corporation).

[0074] [Comparative Example 2] Instead of Coronate L (a trimethylolpropane adduct of tolylene diisocyanate, manufactured by Tosoh Corporation), an oxazoline-based crosslinking agent, Epocross WS-700 (manufactured by Nippon Shokubai Co., Ltd.), was used.

[0075] [Comparative Example 3] Instead of Coronate L (a trimethylolpropane adduct of tolylene diisocyanate, manufactured by Tosoh Corporation), a carbodiimide-based crosslinking agent, Carbodilite V-04 (manufactured by Nisshinbo Chemical Co., Ltd.), was used.

[0076] [Comparative Example 4] Instead of Coronate L (a trimethylolpropane adduct of tolylene diisocyanate, manufactured by Tosoh Corporation), an epoxy-based crosslinking agent, Denacol EX-810 (manufactured by Nagase ChemteX Corporation), was used.

[0077] [ comparison example 5 ] The number of parts by weight of the isocyanate-based crosslinking agent per 100 parts by weight of the β-1,3-glucan derivative was changed from 1.0 part by weight to 0.1 part by weight.

[0078] [Example 10] The number of parts by weight of the isocyanate-based crosslinking agent per 100 parts by weight of the β-1,3-glucan derivative was changed from 1.0 part by weight to 0.5 part by weight.

[0079] [Example 11] The number of parts by weight of the isocyanate-based crosslinking agent per 100 parts by weight of the β-1,3-glucan derivative was changed from 1.0 part by weight to 2 parts by weight.

[0080] [Example 12] The number of parts by weight of the isocyanate-based crosslinking agent per 100 parts by weight of the β-1,3-glucan derivative was changed from 1.0 part by weight to 3 parts by weight.

[0081] [Example 13] The number of parts by weight of the isocyanate-based crosslinking agent per 100 parts by weight of the β-1,3-glucan derivative was changed from 1.0 part by weight to 5 parts by weight.

[0082] [Example 14] The number of parts by weight of the isocyanate-based crosslinking agent per 100 parts by weight of the β-1,3-glucan derivative was changed from 1.0 part by weight to 10 parts by weight.

[0083] [ comparison example 6 ] The number of parts by weight of the isocyanate-based crosslinking agent per 100 parts by weight of the β-1,3-glucan derivative was changed from 1.0 part by weight to 20 parts by weight.

[0084] [ comparison example 7 ] The octanoylated β-1,3-glucan of Synthesis Example 4 was used instead of the myristoylated β-1,3-glucan of Synthesis Example 1. That is, in Example 16, the acyl group in the β-1,3-glucan derivative was changed from myristoyl to octanoyl (R in RCO is 7).

[0085] [ comparison example 8 ] The lauroyl β-1,3-glucan of Synthesis Example 5 was used instead of the myristoylated β-1,3-glucan of Synthesis Example 1. That is, in Example 17, the acyl group in the β-1,3-glucan derivative was changed from myristoyl to lauroyl (R in RCO is 11).

[0086] [Example 18] The palmitoylated β-1,3-glucan of Synthesis Example 6 was used instead of the myristoylated β-1,3-glucan of Synthesis Example 1. That is, the acyl group in the β-1,3-glucan derivative was changed from myristoyl to palmitoyl (R in RCO is 15).

[0087] [evaluation] The pressure-sensitive adhesive tapes 1 of the respective Examples and Comparative Examples were evaluated for the following items. The results are shown in Tables 2 to 5. Note that Example 2 was also included in Tables 2, 4, and 5 to facilitate comparison with the other Examples.

[0088] [Adhesion to stainless steel and polypropylene plates] The adhesive tape 1 was cut to a size of 20 mm in width and 70 mm in length to prepare a sample. Next, the adhesive layer 3 of the adhesive tape 1 was pressed against an adherend made of a stainless steel plate by reciprocating a 2 kg roller in an environment of 23°C and 50% RH. Furthermore, it was left in the same environment for 30 minutes. After that, the peel force (N / 20 mm) was measured when peeled at a peel speed of 300 mm / min and a peel angle of 180° using a precision universal testing machine Autograph AG-IS (Shimadzu Corporation), and the "adhesive force to the stainless steel plate" was obtained. The adhesive force was measured in an environment of 23°C x 50% RH.

[0089] The adherend was changed to a polypropylene plate, and the "adhesive strength to polypropylene plate" was obtained.

[0090] [Holding force] The adhesive tape 1 was cut to a width of 10 mm and a length of 100 mm, and the adhesive surface was pressed against the adherend 6 made of a Bakelite plate by rolling it back and forth once with a 2 kg roller so that the adhesive area was 10 mm wide and 20 mm long, to prepare an adherend sample 7 as shown in FIG. 4. The adherend sample 7 was left in a 23°C atmosphere for 30 minutes, and then left in an 80°C atmosphere for another 30 minutes. Then, a load of 0.5 kg was applied to the lower end of the adhesive tape 1. After leaving it in an 80°C atmosphere for 1 hour (60 minutes) in that state, the slippage length (mm) of the adhesive tape 1 relative to the adherend 6 was measured, and this was obtained as the "holding force". If the adhesive tape 1 fell during the test, the time (minutes) it fell was noted.

[0091] [Contamination of the substrate] The adhesive tape 1 was cut to a size of 20 mm in width and 70 mm in length to prepare a sample 5. The adhesive layer 3 of the sample was pressure-bonded to a stainless steel adherend 6 by reciprocating a 2 kg roller in an environment of 23°C and 50% RH. The sample was left to stand in a thermo-hygrostat at 85°C for one week, and then cooled to room temperature. The adhesive tape 1 was peeled off from the adherend 6, and the adherend 6 was observed. The presence or absence of adhesive composition residue, i.e., contamination of the adherend 6 caused by the adhesive, was observed according to the following criteria.

[0092] Contaminated: White adhesive composition was observed. No contamination: no white adhesive composition was observed.

[0093] [Table 1]

[0094] [Table 2]

[0095] [Table 3]

[0096] [Table 4]

[0097] [Table 5] [Explanation of symbols]

[0098] 1 adhesive tape 2. Base sheet 3 Adhesive layer

Claims

1. A β-1,3-glucan derivative in which an acyl group has been introduced into a β-1,3-glucan, the β-1,3-glucan derivative having a substitution degree of the acyl group of 2.6 or more and less than 3.0; Isocyanate-based crosslinking agent A pressure-sensitive adhesive composition comprising: the acyl group is a myristoyl group or a palmitoyl group, the number of parts by weight of the isocyanate-based crosslinking agent relative to 100 parts by weight of the β-1,3-glucan derivative is 0.5 parts by weight or more and 10 parts by weight or less; A pressure-sensitive adhesive composition, wherein the proportion of the β-1,3-glucan derivative in the pressure-sensitive adhesive composition is 80% by weight or more.

2. The pressure-sensitive adhesive composition according to claim 1, wherein the isocyanate-based crosslinking agent is at least one selected from the group consisting of an adduct-type isocyanate-based crosslinking agent, an isocyanurate-type isocyanate-based crosslinking agent, and an allophanate-type isocyanate-based crosslinking agent.

3. An adhesive tape comprising an adhesive layer comprising the adhesive composition according to claim 1 or 2.

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