Method for producing ion gel, ion gel, solid electrolyte, and actuator

Abstract

To provide a method for producing an ion gel having both of excellent moldability and excellent uniformity.SOLUTION: An method for producing an ion gel includes polymerizing a radical polymerizable compound (A) in a composition, which comprises the radical polymerizable compound (A), a radical polymerization initiator (B), and an ionic liquid (C), with the mass ratio B / A of the content of the radical polymerization initiator to the content of the radical polymerizable compound being 5×10-5-5×10-3, and the mass ratio A / C of the content of the radical polymerizable compound to the content of the ionic liquid being 0.15 or more and less than 2.00, to produce a polymer compound with a number average molecular weight of 450,000-10,000,000, resulting in an ion gel comprising the polymer compound and the ionic liquid.SELECTED DRAWING: None

Description

[Technical field]

[0001] The present invention relates to a method for producing an ion gel, an ion gel, a solid electrolyte, and an actuator. [Background technology]

[0002] Polymer gels (ion gels) are known in which a polymer compound is swollen with an ionic liquid as a solvent. Patent Document 1 describes "a polymer composite containing an ionic liquid and a polymer, the composite being a product of a composition containing an ionic liquid and a monomer cured by active energy rays." [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2018-80236 A Summary of the Invention [Problem to be solved by the invention]

[0004] The present inventors have found that with conventional methods such as that described in Patent Document 1, the moldability of the resulting ion gel is poor, or even if it can be molded, air bubbles may form inside, making it difficult to obtain a uniform molded product.

[0005] Therefore, an object of the present invention is to provide a method for producing an ion gel that has both excellent moldability and excellent uniformity. Another object of the present invention is to provide an ion gel, a solid electrolyte, and an actuator. [Means for solving the problem]

[0006] As a result of extensive investigations aimed at achieving the above object, the present inventors have found that the above object can be achieved by the following configuration.

[0007] [1] A composition comprising a radical polymerizable compound (A), a radical polymerization initiator (B), and an ionic liquid (C), wherein the mass ratio B / A of the content of the radical polymerizable compound to the content of the radical polymerization initiator is 5×10 -5 ~5×10 -3 a ratio A / C, based on a mass standard, of the content of the radical polymerizable compound to the content of the ionic liquid is 0.15 or more and less than 2.00, and the radical polymerizable compound is polymerized to produce a polymer compound having a number average molecular weight of 450,000 to 10,000,000, thereby obtaining an ion gel containing the polymer compound and the ionic liquid. [2] The above B / A is 3×10 -3 The method for producing an ion gel according to [1], wherein the ionic gel is less than 100%. [3] The above B / A is 5×10 -4 The method for producing an ion gel according to [1], wherein the ionic gel is less than 100%. [4] The method for producing an ionic gel according to any one of [1] to [3], wherein the radical polymerizable compound is at least one selected from the group consisting of (meth)acrylic acid, (meth)acrylic acid esters, (meth)acrylamide, and (meth)acrylonitrile. [5] The method for producing an ionic gel according to [4], wherein the radically polymerizable compound is (meth)acrylic acid or a (meth)acrylic acid ester. [6] The method for producing an ionic gel described in [4], wherein the radically polymerizable compound is methacrylic acid or a methacrylic acid ester. [7] The method for producing an ion gel according to [5] or [6], wherein the ionic liquid is an ionic liquid represented by the formula 8 described below. [8] R in the above formula 8 83 , and R 84 The method for producing an ion gel according to [7], wherein each of the groups is independently a perfluoroalkyl group. [9] R in the above formula 8 83 , and R 84are each independently selected from the group consisting of a trifluoromethyl group and a pentafluoroethyl group.

[10] A composition comprising a radical polymerizable compound, a radical polymerization initiator, and an ionic liquid, wherein the mass ratio of the content of the radical polymerizable compound to the content of the radical polymerization initiator is 5×10 -5 ~5×10 -3 The ionic gel obtained by curing the composition comprising:

[11] The ion gel according to

[10] , wherein the radical polymerizable compound is (meth)acrylic acid or a (meth)acrylic acid ester.

[12] The ion gel according to

[10] or

[11] , wherein the ionic liquid is an ionic liquid represented by the following formula 8.

[13] R in Equation 8 83 , and R 84 Each of the groups independently represents a perfluoroalkyl group.

[14] A solid electrolyte comprising the ion gel according to any one of

[10] to

[13] .

[15] An actuator having a solid electrolyte according to

[14] . Effect of the Invention

[0008] According to the present invention, an ion gel having excellent moldability can be produced. Also, according to the present invention, an ion gel, a solid electrolyte, and an actuator can be provided. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0009] The present invention will be described in detail below. The following description of the components may be based on a representative embodiment of the present invention, but the present invention is not limited to such an embodiment. In this specification, a numerical range expressed using "to" means a range that includes the numerical values ​​before and after "to" as the lower and upper limits.

[0010] In addition, in this specification, "(meth)acrylate" refers to both or either of acrylate and methacrylate, "(meth)acrylic" refers to both or either of acrylic and methacrylic, and "(meth)acryloyl" refers to both or either of acryloyl and methacryloyl.

[0011] [Method of manufacturing ion gel] Ion gels have been prepared by directly mixing an ionic liquid with a polymer compound, but this method requires a lot of time for preparation due to the high viscosity of the ionic liquid, and the resulting ion gel tends to be non-uniform. There is also a method in which a polymer compound is dissolved in a solvent and then mixed with an ionic liquid (or a mixture of an ionic liquid and a solvent), but in this case, it is necessary to distill off the solvent from the resulting mixture. If the solvent cannot be completely distilled off, the remaining solvent may volatilize during thermoforming, causing air bubbles in the molded product.

[0012] In contrast, the method described in Patent Document 1 is expected to produce a relatively uniform ion gel, but the inventors' investigations have revealed that there are still areas that need improvement in terms of moldability and uniformity.

[0013] The present inventors have investigated factors that affect the moldability and uniformity of ion gels, and have found that when the number-average molecular weight of a polymer compound contained in an ion gel is low, the resulting ion gel becomes fluid, and as a result, moldability is likely to deteriorate.

[0014] In addition, when the conversion rate of the radical polymerizable compound is insufficient, the radical polymerizable compound remains in the ion gel. In this case, when the obtained ion gel is subjected to thermal molding, the radical polymerizable compound vaporizes, generating bubbles in the ion gel, and the ion gel tends to become non-uniform in appearance and mechanical properties.

[0015] Therefore, the inventors considered that if both the molecular weight of the polymer compound and the conversion rate of the radical polymerizable compound could be improved, an ion gel having excellent moldability and excellent uniformity could be obtained.

[0016] In solution radical polymerization using a general radical polymerization initiator, it is known that the molecular weight of the resulting polymer compound and the conversion rate of the radical polymerizable compound can be changed by adjusting the amount of the radical polymerization initiator relative to the radical polymerizable compound.

[0017] However, it has been conventionally believed that there is a trade-off between the molecular weight of the resulting polymer compound and the conversion rate of the radically polymerizable compound. For example, in order to increase the molecular weight of the resulting polymer compound, the content of the radical polymerization initiator contained in the composition containing the radical polymerizable compound may be reduced. However, it has been thought that reducing the content of the radical polymerization initiator in the composition reduces the conversion rate of the radical polymerizable compound, and as a result, it is difficult to obtain a compound with an intended high molecular weight.

[0018] In other words, because there is a trade-off between the molecular weight of a polymer compound and the conversion rate of a radically polymerizable compound, it has been thought that it is difficult to improve both the molecular weight and the conversion rate, no matter how much the content of the radical polymerization initiator is adjusted (reduced).

[0019] However, the present inventors have continued to conduct intensive research without being bound by the above common knowledge. As a result, they have surprisingly found that the B / A ratio in a composition containing a radical polymerizable compound (A), a radical polymerization initiator (B), and an ionic liquid (C) is 5×10 -5 ~5×10 -3 It has been found that by doing so, it is possible to maintain a high conversion rate while making it possible to make the number average molecular weight of the obtained polymer 450,000 to 10,000,000. The above facts are unexpected results from the perspective of common general technical knowledge, and the present inventors have continued their research efforts without being bound by common general knowledge, leading to the completion of the present invention.

[0020] <Composition> The composition used in the present production method contains a radical polymerizable compound (A), a radical polymerizable compound (B), and an ionic liquid (C). Each component contained in the composition will be described in detail below.

[0021] (Radical polymerizable compound) The radically polymerizable compound (A) is a compound having at least one radically polymerizable group in the molecule, and is preferably a compound having one radically polymerizable group in the molecule.

[0022] Examples of the radically polymerizable group include groups having an ethylenically unsaturated bond such as a vinyl group, a (meth)acryloyl group, and an allyl group. Of these, a (meth)acryloyl group is preferred.

[0023] The molecular weight of the radically polymerizable compound is not particularly limited, but is generally preferably 50 or more and 1,000 or less.

[0024] Examples of the radically polymerizable compound include carboxy group-containing compounds such as (meth)acrylic acid, carboxyethyl (meth)acrylate, carboxypentyl (meth)acrylate, itaconic acid, maleic acid, fumaric acid, and crotonic acid, as well as esters thereof; amide compounds such as (meth)acrylamide, N,N-dimethyl (meth)acrylamide, N,N-diethyl (meth)acrylamide, N-hexyl (meth)acrylamide, N-methyl (meth)acrylamide, N-butyl (meth)acrylamide, N-butyl (meth)acrylamide, N-methylol (meth)acrylamide, and N-methylolpropane (meth)acrylamide; and cyano (meth)acrylate compounds such as (meth)acrylonitrile.

[0025] The radical polymerizable compound is preferably at least one compound selected from the group consisting of (meth)acrylic acid, (meth)acrylic acid esters, (meth)acrylamide, and (meth)acrylonitrile, and more preferably (meth)acrylic acid or (meth)acrylic acid esters.

[0026] From the viewpoint of providing an ion gel with superior moldability, particularly in terms of ease in repeating softening by heating and hardening by cooling, at least one compound selected from the group consisting of methacrylic acid, methacrylic acid esters, methacrylamide, and methacrylonitrile, which are less likely to cause branching in the molecular chain of the resulting polymer compound, is preferred, and methacrylic acid or methacrylic acid esters are more preferred.

[0027] The content of the radical polymerizable compound in the composition is such that the mass ratio (B / A) of the content of the radical polymerizable compound (A) to the content of the radical polymerization initiator (B) described below is 5×10 -5 ~5×10 -3 B / A is adjusted to 3×10 -3 Less than 5×10 is preferable. -4 Less than 3×10 is preferable. -4 It is more preferable that the B / A ratio is rounded to one significant digit.

[0028] B / A is 5 x 10 -5 If the conversion rate is less than 100%, the conversion rate of the radical polymerizable compound will be low. If the conversion rate is low, the radical polymerizable compound will remain in the ion gel, and when the ion gel is thermoformed, the radical polymerizable compound will volatilize, forming bubbles, etc., making it impossible to obtain an ion gel with excellent uniformity. On the other hand, B / A is 5×10 -3 If the polymerization degree exceeds this value, the degree of polymerization becomes low, the resulting ion gel becomes fluid, and an ion gel having excellent moldability cannot be obtained.

[0029] In addition, B / A is 3×10 -3 If it is less than 5 × 10, the number average molecular weight of the polymer compound tends to be large, which is preferable.-4 When the molecular weight is less than 1, the number average molecular weight of the polymer compound tends to become larger, which is preferable.

[0030] The composition may contain one type of polymerizable compound alone or two or more types. When the composition contains two or more types of polymerizable compounds, the total content is preferably within the above numerical range.

[0031] (Radical polymerization initiator) The radical polymerization initiator contained in the present composition includes a thermal radical polymerization initiator and a photoradical polymerization initiator.

[0032] Examples of the thermal radical polymerization initiator include peroxides such as t-butyl peroxybenzoate, di-t-butyl peroxide, cumene perhydroxide, acetyl peroxide, benzoyl peroxide, and lauroyl peroxide; and azo compounds such as azobisisobutyronitrile, azobis-2,4-dimethylvaleronitrile, and azobiscyclohexanecarbonitrile.

[0033] Examples of the photoradical polymerization initiator include 1-hydroxy-cyclohexyl-phenyl-ketone, 2-hydroxy-2-methyl-1-phenyl-propan-1-one, 2,2-dimethoxy-1,2-diphenylethan-1-one, 2-methyl-1-(4-methylthiophenyl)-2-morpholinopropan-1-one, and 2,4,6-trimethylbenzoyl-diphenyl-phosphine oxide.

[0034] The content of the radical polymerization initiator in the composition is adjusted so that the mass ratio (B / A) to the radical polymerizable compound is within a predetermined range, and is preferably 0.0001 to 3 parts by mass when the total content of the radical polymerizable compound and the content of the ionic liquid in the composition is 100 parts by mass. The composition may contain one type of radical polymerization initiator alone or two or more types. When the composition contains two or more types of radical polymerization initiators, the total content is preferably within the above numerical range.

[0035] (Ionic Liquid) As used herein, ionic liquid refers to a non-volatile salt formed by the combination of a cation and an anion, the salt having a melting point of 25° C. or less under atmospheric pressure.

[0036] The cation constituting the ionic liquid is preferably at least one selected from the group consisting of organic cations and metal complex cations, and preferably contains an organic cation or is preferably made of an organic cation. In this specification, the organic cation means a cation that does not contain a metal atom and has at least one carbon atom.

[0037] The organic cation is not particularly limited, but examples thereof include onium ions. More specifically, ammonium ions (e.g., R A 4N + ), iminium ions (e.g., R B 2C=N + R 1 2), sulfonium ions (e.g., R A 3S + ), oxonium ions (e.g., R A 2O + ), phosphonium ion (representative structure: R A 4P + ), and iodonium ions (e.g., R A 2I + ) etc. In the above formulas, R A R represents a substituent such as an alkyl group, an aryl group, or a heterocyclic group. B represents a hydrogen atom or a monovalent substituent. 1 , multiple R in molecule B , or R in the molecule A and R Bmay be bonded to each other to form a ring. A , or two R B together form a double bond group (e.g., =O, =S, =NR B ) may be formed.

[0038] The metal complex cation is not particularly limited, and examples thereof include ferrocene-based, cobaltocene-based, ruthenium-based, and solvated ions of lithium, sodium, and the like, whose high Lewis acidity is lowered by coordination with crown ether or the like.

[0039] Other forms of cations include ammonium ions, pyrrolidinium ions, pyridinium ions, piperidinium ions, oxazolium ions, oxazolinium ions, imidazolium ions, thiazolium ions, and phosphonium ions.

[0040] Ammonium ion An example of the ammonium ion is a cation represented by the following formula 1. [ka]

[0041] In formula 1, R 1 Each independently represents a hydrogen atom or a monovalent substituent, and a plurality of R 1 may be the same or different. 1 The monovalent substituent is not particularly limited, and examples thereof include substituted or unsubstituted hydrocarbon groups having 1 to 15 carbon atoms which may contain a hetero atom.

[0042] Pyrrolidinium ion An example of the pyrrolidinium ion is a cation represented by the following formula 2. [ka]

[0043] In formula 2, R2 Each independently represents a hydrogen atom or a monovalent substituent, and a plurality of R 2 may be the same or different. 2 The monovalent substituent is not particularly limited, and examples thereof include substituted or unsubstituted hydrocarbon groups having 1 to 15 carbon atoms which may contain a hetero atom.

[0044] Piperidinium ion An example of the piperidinium ion is a cation represented by the following formula 3. [ka]

[0045] In formula 3, R 3 Each independently represents a hydrogen atom or a monovalent substituent, and a plurality of R 3 may be the same or different. 3 The monovalent substituent is not particularly limited, and examples thereof include substituted or unsubstituted hydrocarbon groups having 1 to 15 carbon atoms which may contain a hetero atom.

[0046] Pyridinium ion An example of the pyridinium ion is a cation represented by the following formula 4. [ka]

[0047] In formula 4, R 4 Each independently represents a hydrogen atom or a monovalent substituent, and a plurality of R 4 may be the same or different. 4 The monovalent substituent is not particularly limited, and examples thereof include substituted or unsubstituted hydrocarbon groups having 1 to 15 carbon atoms which may contain a hetero atom.

[0048] Imidazolium ion An example of the imidazolium ion is a cation represented by the following formula 5. [ka]

[0049] In formula 5, R 5 Each independently represents a hydrogen atom or a monovalent substituent, and a plurality of R 5 may be the same or different. 5 The monovalent substituent is not particularly limited, and examples thereof include substituted or unsubstituted hydrocarbon groups having 1 to 15 carbon atoms which may contain a hetero atom.

[0050] The phosphonium ion may, for example, be a cation represented by the following formula 6: [ka]

[0051] In formula 6, R 6 Each independently represents a hydrogen atom or a monovalent substituent, and a plurality of R 6 may be the same or different. 6 The monovalent substituent is not particularly limited, and examples thereof include substituted or unsubstituted hydrocarbon groups having 1 to 15 carbon atoms which may contain a hetero atom.

[0052] The anion constituting the ionic liquid is not particularly limited, and known anions can be used. Among them, the anion is preferably an anion containing a halogen atom. The halogen atom is not particularly limited, but is preferably fluorine or bromine, and more preferably fluorine.

[0053] The anion containing a halogen atom is not particularly limited, and examples thereof include anions represented by the following formula 7. [ka]

[0054] In formula 7, R 7represents a halogenated alkyl group, and preferably a fluorinated alkyl group. 7 may be the same or different. 7 may be linked to each other to form a ring.

[0055] Specific examples of the anion include bis(fluorosulfonyl)imide (FSI), bis(trifluoromethanesulfonyl)imide (TFSI), bis(pentafluoroethylsulfonyl)imide (BETI), N,N-bis(nonafluorobutanesulfonyl)imide (NFSI), and N,N-hexafluoropropane-1,3-disulfonylimide (cTFSI).

[0056] As the ionic liquid, an ionic liquid represented by the following formula 8 is preferred, since it gives an ionic gel having better moldability and uniformity.

[0057] [ka]

[0058] In formula 8, R 81 , and R 82 R each independently represents an alkyl group having 1 to 10 carbon atoms, and more preferably an alkyl group having 1 to 4 carbon atoms. 81 The number of carbon atoms in the alkyl group of R 82 may have the same or different numbers of carbon atoms, but preferably have different numbers of carbon atoms.

[0059] R 83 , and R 84 each independently represents a monovalent organic group and may be the same or different. That is, the structure of the anion may be symmetric or asymmetric.

[0060] As the monovalent organic group, for example, a substituted or unsubstituted hydrocarbon group which may have a heteroatom is preferable, and in order to obtain an ion gel having a more excellent effect of the present invention, R 83 , and R 84are each independently preferably a halogenated alkyl group, and more preferably a perfluoroalkyl group. The number of carbon atoms in the halogenated alkyl group is not particularly limited, but is preferably 1 to 10, more preferably 1 to 8, and even more preferably 1 to 6.

[0061] The perfluoroalkyl group is preferably at least one group selected from the group consisting of -C4F9, -C3F7, -C2F5, and -CF3. From the viewpoint of providing an ion gel with superior moldability, -C2F5 (pentafluoroethyl group) or -CF3 (trifluoromethyl group) is preferred, and -CF3 is more preferred.

[0062] The content of the ion gel in the composition is adjusted so that the mass ratio (A / C) of the content of the radical polymerizable compound (A) to the content of the ionic liquid (C) in the composition is 0.15 or more and less than 2.00. If A / C is less than 0.15, the fluidity of the resulting ion gel will be too high, making it impossible to obtain an ion gel with sufficient moldability.If A / C is 2.00 or more, the fluidity of the ion gel will be too low, making it impossible to obtain an ion gel with sufficient moldability.

[0063] A / C is preferably 1.0 or less, and more preferably less than 1.0, in that an ion gel having a more excellent effect of the present invention can be obtained. When A / C is 0.60 or less, the resulting ion gel has better moldability, and when A / C is 0.40 or less, the resulting ion gel has better moldability and better uniformity.

[0064] The composition can be prepared by mixing the components. The mixing method and order are not particularly limited, but an example of the method is mixing a radical polymerizable compound and a radical polymerization initiator, and then mixing the ionic liquid.

[0065] The method for polymerizing the radically polymerizable compound in the composition to produce a polymer compound having a number average molecular weight of 450,000 to 10,000,000 is not particularly limited, and a known method may be appropriately selected depending on the type of radical polymerization initiator. For example, when the composition contains a thermal radical polymerization initiator, it may be heated in an inert gas atmosphere at a temperature of room temperature to 130° C. for 1 to 72 hours.

[0066] The conversion rate (%) of the radical polymerizable compound is not particularly limited, but from the viewpoint of obtaining an ion gel having a more excellent effect of the present invention, it is preferably 70% or more, more preferably more than 70%, even more preferably 90% or more, and particularly preferably more than 90%. The upper limit is generally 100% or less. The conversion rate of the radical polymerizable compound means a value determined by the method described in the examples.

[0067] The number average molecular weight of the polymer compound obtained by radical polymerization is 450,000 to 10,000,000. If the molecular weight is less than 450,000, an ion gel having both sufficient moldability and uniformity cannot be obtained. From the viewpoint of obtaining an ion gel having a more excellent effect of the present invention, the number average molecular weight of the polymer compound is preferably 900,000 or more, and more preferably 1,350,000 or more. The number average molecular weight of the polymer compound means a value measured by the method described in the Examples.

[0068] The degree of polymerization of the polymer compound is not particularly limited, but is preferably at least 4,500, more preferably at least 9,000, and even more preferably at least 14,000. The upper limit is not particularly limited, but is preferably 100,000 or less.

[0069] When the radically polymerizable compound is polymerized, a polymer compound is produced, and an ion gel containing the polymer compound and the ionic liquid is obtained. According to this production method, the radical polymerizable compound is polymerized in a homogeneous composition containing the radical polymerizable compound, the radical polymerization initiator, and the ionic liquid, and thus the obtained ion gel has excellent uniformity. In addition, by setting B / A within a predetermined range, it is possible to simultaneously improve two parameters, namely, molecular weight and conversion rate, which have been considered to be in a trade-off relationship in the past. Therefore, the obtained ion gel has both excellent moldability and excellent uniformity.

[0070] The ion gel obtained by this production method has ion conductivity and can be easily thermoformed, so it can be formed into a sheet and used as a solid electrolyte. In addition, if this solid electrolyte is sandwiched between a pair of electrodes, it can also be used as an actuator element. EXAMPLES

[0071] The present invention will be described below with reference to examples, but the present invention is not limited to these.

[0072] [Example 1: Preparation of ion gel] Methyl methacrylate (MMA, Kanto Chemical) was purified by passing it through a short column of activated alumina to remove the polymerization inhibitor hydroquinone. Next, α,α′-azobisisobutyronitrile (AIBN) powder (0.1 parts by mass) and purified MMA (30 parts by mass) were added to a 5 mL vial and completely dissolved. Next, 1-ethyl-3-methylimidazolium bis(trifluoromethanesulfonyl)imide ([C2mIm][TFSI], Iolitec) (70 parts by mass) was added to the resulting solution to obtain a uniform and transparent pre-gel solution.

[0073] The vial was then sealed with a silicone double cap and bubbled with argon for 10 minutes using a syringe needle, after which the vial was placed in an oven heated to 80°C and heated for 24 hours without stirring to obtain an ion gel.

[0074] [Examples 2 to 10, Comparative Examples 1 to 7] The ion gels of Examples 2 to 10 and Comparative Examples 1 to 7 were prepared in the same manner as in Example 1, except that the types and contents of each component of the pre-gel solution were as shown in Table 1.

[0075] The meanings of the abbreviations in Table 1 are as follows: MMA: Methyl methacrylate EMA: Ethyl methacrylate [C2mIm][BETI]: 1-Ethyl-3-methylimidazolium bis(pentafluoroethanesulfonyl)imide [C2mIm][NFSI]: 1-ethyl-3-methylimidazolium N,N-bis(nonafluorobutanesulfonyl)imide [C2mIm][OTf]: 1-Ethyl-3-methylimidazolium trifluoromethanesulfonate

[0076] [conversion] The conversion of the radical polymerizable compound (unit: %, conversion rate) was measured by the following procedure. Note that the following explanation is for the case where MMA was used as the radical polymerizable compound, but the same applies when EMA was used.

[0077] First, the ion gel was completely dissolved in chloroform-d (manufactured by ACROS ORGANICS, product number 46402-0075) to obtain a solution. Next, the obtained solution was introduced into an NMR sample tube, and NMR measurement (JEOL, ECZ 400S) was performed at 25°C. From the obtained NMR spectrum, the ratio of the number of residual monomers (radical polymerizable compounds) in the ion gel to the number of MMA units in the polymer was calculated, and the conversion was obtained by the following formula.

[0078]

number

[0079] [Number average molecular weight] The number average molecular weight of the obtained ion gel was measured by GPC. The details of the measurement procedure are as follows.

[0080] (Pretreatment) Each ion gel was purified by reprecipitation. Specifically, the ion gel was dissolved in acetone to a concentration of 1% by mass. Next, the solution was dropped into a large amount of methanol (20 times by volume) to precipitate the polymer (polymer compound). Polymer powder was obtained by suction filtration.

[0081] The polymer powder was again dissolved in acetone, precipitated, and filtered in the same manner, and the obtained polymer powder was vacuum dried for 24 hours at 60° C. Next, the polymer powder was dissolved in an eluent (10 mM LiBr / DMF) to a concentration of 0.1 mass%, and passed through a 0.45 μm syringe filter before being used for measurement.

[0082] (GPC measurement) Device configuration Degasser / JAPAN SPECTRA (DG-2080-53) Pump: JASCO (PU-2080) Interface box / JASCO (LC-Net II / ADC) Column oven / JASCO (CO-4060) RI detector / JASCO (RI-4030) Column: Two Shodex (registered trademark) SB-806M HQ columns connected directly Guard column: Shodex (registered trademark) SB-G 6B

[0083] Standards Type: Polymethyl methacrylate (PMMA) Manufacturer: Shodex (registered trademark) ·Product: STANDARD M-75 Molecular weight range: 2,870~965,000 (7 points)

[0084] Measurement conditions Column temperature: 40℃ ·Flow rate: 1mL / min ·Elution phase: 10mM LiBr / DMF Detection: RI

[0085] analysis A calibration curve was created by linear regression (least squares method) of a third order equation for seven standard samples. Molecular weights exceeding 965,000 were extrapolated using the above calibration curve.

[0086] [Table 1]

[0087] [Moldability] The moldability of the ion gel was evaluated by the following method. The prepared ion gel was placed in a 2 mm high silicone spacer with a 5 cm x 5 cm opening in the center, sandwiched between release films on the top and bottom, and further sandwiched between stainless steel plates on the outside, and compressed using a small press (ASONE, H300-15) heated to 130°C. The compressed state was evaluated according to the following criteria. The results are shown in Table 2.

[0088] AA: It was molded nicely. A: It is possible to mold it by slowing down the compression speed, but if the compression speed is too fast, cracks will appear on the edges. B: The shape could not be maintained and molding was not possible.

[0089] [Uniformity of molded product] The uniformity of the molded products obtained was evaluated according to the following criteria. The odor of the molded products was also evaluated. The results are shown in Table 2.

[0090] AA: There were no visible bubbles within a 10mm square area, and the product was uniform. In addition, the product was odorless. A: There were 1 to 3 visible air bubbles in a 10 mm square area, but the transparency was maintained, and when placed on a piece of paper with writing on it, the writing underneath was readable. There was a slight odor of monomer. B: There were 4 or more visible bubbles in a 10mm square area, some of the text was illegible, and the monomer smell was stronger.

[0091] [Table 2]

[0092] In Table 2, "90<" means over 90%, "~70" means 70% or less, and "-" means that the test could not be performed. From the results in Tables 1 and 2, the ion gels obtained by the manufacturing methods of Examples 1 to 10 had excellent moldability and excellent uniformity. On the other hand, the ion gels obtained by the manufacturing methods of Comparative Examples 1 to 3 and Comparative Examples 5 to 7 had poor moldability, and the desired molded products were not obtained. Moreover, the manufacturing method of Comparative Example 4 did not produce an ion gel with the desired uniformity.

[0093] B / A is 3 x 10 -3 In the production method of Example 3 using a composition having a molecular weight of less than 1000, the number average molecular weight of the obtained polymer compound was higher than that in the production method of Example 1. Also, B / A is 5×10 -4 In the production method of Example 3 using a composition having a number average molecular weight of less than 100%, the number average molecular weight of the obtained polymer compound was even higher than that of the production method of Example 2. Moreover, in the production method of Example 4, which used a composition with an A / C of 0.60 or less, the resulting ion gel had superior moldability compared to the production method of Example 5. Moreover, the production method of Example 4, which used a composition with an A / C ratio of 0.40 or less, gave an ion gel with superior uniformity compared to the production method of Example 3.

[0094] In addition, the ion gel has a structure represented by formula 8, and the anion R 83 In the production methods of Examples 3 and 6, which used compositions in which n was a trifluoromethyl group and n was a pentafluoroethyl group, respectively, the resulting ion gels had superior moldability as compared to the production method of Example 7. [Industrial Applicability]

[0095] The ion gel produced by the ion gel production method of the present invention has both excellent moldability and excellent uniformity, and can be easily molded by heating, so that it can be used as a solid electrolyte, an actuator element, etc.

Claims

1. The composition contains a radical polymerizable compound (A), a radical polymerization initiator (B), and an ionic liquid (C), and the mass ratio B / A of the content of the radical polymerization initiator to the content of the radical polymerizable compound is 5×10 －５ ~5×10 －３ a ratio A / C, based on a mass standard, of the content of the radical polymerizable compound to the content of the ionic liquid is 0.15 or more and less than 2.00, and the radical polymerizable compound is polymerized to produce a polymer compound having a number average molecular weight of 450,000 to 10,000,000, thereby obtaining an ion gel containing the polymer compound and the ionic liquid.

2. The B / A is 3×10 －３ The method for producing the ionic gel according to claim 1, wherein the ionic gel is less than 100% by mass.

3. The B / A is 5×10 －４ The method for producing the ionic gel according to claim 1, wherein the ionic gel is less than 100% by mass.

4. The method for producing an ion gel according to any one of claims 1 to 3, wherein the radical polymerizable compound is at least one selected from the group consisting of (meth)acrylic acid, (meth)acrylic acid esters, (meth)acrylamide, and (meth)acrylonitrile.

5. The method for producing an ionic gel according to claim 4 , wherein the radically polymerizable compound is (meth)acrylic acid or a (meth)acrylic acid ester.

6. The method for producing an ionic gel according to claim 4 , wherein the radical polymerizable compound is methacrylic acid or a methacrylic acid ester.

7. The method for producing an ion gel according to claim 5 or 6, wherein the ionic liquid is an ionic liquid represented by the following formula 8: 【Chemistry 1】 (In formula 8, R ８１ , and R ８２ each independently represents an alkyl group having 1 to 10 carbon atoms; R ８３ , and R ８４ each independently represents a monovalent organic group.

8. R in the above formula 8 ８３ , and R ８４ The method for producing an ionic gel according to claim 7 , wherein each of the groups independently represents a perfluoroalkyl group.

9. R in the above formula 8 ８３ , and R ８４ The method for producing an ionic gel according to claim 7 , wherein each of the groups independently represents a group selected from the group consisting of a trifluoromethyl group and a pentafluoroethyl group.

10. An ionic gel obtained by curing a composition, comprising: The composition contains a radical polymerizable compound, a radical polymerization initiator, and an ionic liquid, and the ratio of the content of the radical polymerization initiator to the content of the radical polymerizable compound on a mass basis is 5×10 －５ ~5×10 －３ and the radical polymerizable compound is composed only of a compound having one radical polymerizable group in the molecule, The ion gel is a polymer compound having a number average molecular weight of 450,000 to 10,000,000 obtained by polymerizing the radical polymerizable compound; An ion gel comprising the ionic liquid.

11. The ion gel according to claim 10 , wherein the radically polymerizable compound is (meth)acrylic acid or a (meth)acrylic acid ester.

12. The ion gel according to claim 10 or 11, wherein the ionic liquid is an ionic liquid represented by the following formula 8: 【Chemistry 2】 (In formula 8, R ８１ , and R ８２ each independently represents an alkyl group having 1 to 10 carbon atoms; R ８３ , and R ８４ each independently represents a monovalent organic group.

13. R in Formula 8 ８３ , and R ８４ The ionic gel of claim 12 , wherein each of the groups is independently a perfluoroalkyl group.

14. A solid electrolyte comprising the ion gel according to any one of claims 10 to 13.

15. An actuator comprising the solid electrolyte according to claim 14.

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