JP5764361B2 - Dielectric and capacitor-type storage battery - Google Patents

Description

The present invention relates to a dielectric used for a capacitor-type storage battery and a capacitor-type storage battery using the dielectric.

  In recent years, in order to prevent global warming, it is necessary to efficiently store and store the generated energy. As such power storage systems, applications such as secondary batteries such as nickel metal hydride batteries and lithium ion batteries, electric double layer capacitors, lithium ion capacitors, etc. that have made significant progress until reaching the theoretical energy density as storage batteries for portable devices have been attempted. ing. These power storage systems use, for example, an electrolyte using a rare metal such as lithium (for example, Patent Document 1).

  When an electrolyte is used for a storage battery, charging takes time. Further, since the electrolyte is deteriorated, the life of the storage battery is short. Moreover, in order to implement | achieve a high output voltage, it was necessary to connect a some storage battery in series. On the other hand, when a capacitor is used as a storage battery, the charging time is short, the life is long, and a high output voltage can be realized. However, when a capacitor is used as a storage battery, it is necessary to increase the capacity per unit volume. For this purpose, a material having a high relative dielectric constant is required.

Japanese Patent No. 4428830

  An object of the present invention is to provide a dielectric having a high relative dielectric constant and a capacitor-type storage battery using the same and having a large electrostatic capacity. .

The above problem is solved by the following means. That is,
The dielectric of the present invention is
A resin having a crosslinked structure ;
A metal ion that is an ionic oligomer having a molecular chain with a metal salt structure ;
It is the dielectric material comprised including.

Also, relaxation time _{T 2} of the pulse NMR of resin having a crosslinked structure may be a both long and 500 .mu.s.
Further, when the resin having a crosslinked structure is a (meth) acrylic resin, the crosslinking ratio is preferably at least 5%, and at least one crosslinkable with respect to its weight average molecular weight of 1000. It is preferable to have a cross-linked structure by a cross-linking reaction of at least a part of the cross-linkable group.

The capacitor-type storage battery of the present invention is
A pair of electrodes;
A dielectric disposed between the pair of electrodes, the dielectric according to any one of the above-described aspects of the present invention,
It is a capacitor type storage battery having

  According to the present invention, it is possible to provide a dielectric having a high relative dielectric constant, and a capacitor-type storage battery using the dielectric having a high electrostatic capacity.

It is a schematic block diagram which shows an example of the capacitor type storage battery of this invention. It is a graph which shows the relationship of the pulse NMR relaxation time of resin, an electrostatic capacitance, and a leakage current in Examples 1-14 and Comparative Example 1.

  The present invention will be described in detail.

(Dielectric)
The dielectric of the present invention includes a resin and metal ions. However, in the dielectric of the present invention, a resin having a crosslinked structure is applied as the resin, and a metal ion that is an ionic oligomer having a molecular chain having a metal salt structure is applied as the metal ion.
Conventionally, a dielectric composed only of a resin is composed of a substance having a small polarization, so that a large relative dielectric constant, that is, a capacitance cannot be obtained in a capacitor-type storage battery.
On the other hand, in the dielectric of the present invention, the dielectric constant is increased by mixing metal ions, which are highly polarizable substances, into the resin. And a capacitance becomes large in a capacitor type storage battery.
That is, in the dielectric of the present invention, the direction of the metal ions is changed by the electric field, so that a space charge distribution is generated, resulting in polarization, and a relative dielectric constant is increased.

In the dielectric of the present invention, the metal ion may be contained in the resin as a compound having a molecular chain having a metal salt structure (hereinafter referred to as “ionic oligomer”).
When metal ions are mixed into a resin alone, the metal ions move freely in the resin (dielectric material) and, for example, easily reach the electrode placed in contact with the dielectric material. The storage battery may not be able to hold power for a long time.
In addition, when a compound having a molecular chain with a metal salt structure is used as a resin and the compound itself is configured as a dielectric, the capacitance is improved as in the case of a single metal ion, but the molecular chain having a metal salt structure is dielectric. It moves freely in the body, the leakage current increases, and the capacitor-type storage battery cannot hold power for a long time. Furthermore, when manufacturing a capacitor-type storage battery, the fluidity may cause contact between the electrodes, resulting in poor yield.

On the other hand, when the ionic oligomer is mixed in the resin, it is considered that the molecular chain of the ionic oligomer is caught by the molecular chain of the resin, so that the free movement of the ionic oligomer in the resin is suppressed.
In other words, the ionic oligomer is in a state where the orientation of the metal ions constituting the metal salt structure can function as a polarizer (that is, the orientation of the metal ions to polarize due to space charge distribution). It is considered that the movement is suppressed and contained in the resin.
Thereby, in the dielectric of this invention, when an ionic oligomer is mixed in resin, a leak current can also be reduced, improving a dielectric constant. As a result, the capacitor-type storage battery can retain electricity for a long time while ensuring a high capacitance.

In the dielectric according to the present invention, the resin preferably has a crosslinked structure.
When the ionic oligomer is mixed in an uncrosslinked resin, movement in the resin is suppressed and leakage current is reduced, but the reduction may not be sufficient.

On the other hand, when the resin has a cross-linked structure, the movement of the ionic oligomer is considered to be limited by the network structure of the molecular chain formed by the cross-linked structure.
In other words, the ionic oligomer is polarized within the network of molecular chains formed by the cross-linked structure of the resin so that the metal ions constituting the metal salt structure function as a polarizer (that is, a space charge distribution is generated). Change of the direction of the metal ions for that purpose), while its movement is limited and is considered to be contained in the resin.
Thereby, in the dielectric of the present invention, when the resin has a cross-linked structure, the leakage current can be reduced while improving the relative permittivity more effectively than the non-cross-linked resin.

Hereinafter, the dielectric of the present invention will be described in more detail.
First, metal ions will be described.
Examples of the metal ions include one selected from ions of metals belonging to Group 1 of the periodic table, ions of metals belonging to Group 2 of the periodic table, and ions of metals belonging to Group 13 of the Periodic Table. Preferably mentioned.

Typical examples of metals belonging to Group 1 of the periodic table include lithium (Li), sodium (Na), and potassium (K).
Typical examples of metals belonging to Group 2 of the periodic table include magnesium (Mg) and calcium (Ca).
Typical examples of the metals belonging to Group 13 of the periodic table include boron (B) and aluminum (Al).

  Among these metal ions, ions of group 1 of the periodic table are particularly preferable from the viewpoint that polarization is likely to occur due to low electronegativity.

The content of metal ions is, for example, 0.5% to 50%, preferably 2% to 30%, and more preferably 5% to 20% with respect to the resin.
In addition, this content is a thing when a metal ion simple substance is included in resin.

Next, the ionic oligomer will be described.
An ionic oligomer is a compound having a molecular chain having a metal salt structure. That is, the ionic oligomer is a material (oligomer) that contains the metal ion that functions as a polarizer and is mixed in the resin.
Specific examples of the ionic oligomer include, for example, a polymer having a monomer having a metal base as at least a polymerization component and having a molecular chain (for example, alkyl chain, amide chain, etc.) formed by polymerization (for example, the number of monomer bonds) 10 to 100 oligomers).

  The ionic oligomer only needs to have, for example, at least one monomer having a metal base as a polymerization component thereof, and may be a homopolymer of a monomer having a metal base, or other monomer (metal base). And a copolymer with a monomer having no).

Examples of the monomer having a metal base include a monomer having a hydroxyl group, in which a hydrogen atom of the hydroxyl group is modified (substituted) with a metal ion.
Monomers with metal bases are monomers with carboxylate metal bases modified (substituted) by hydrogen ions of carboxylic acid groups, metal sulfonates with hydrogen atoms of sulfonic acid groups modified (substituted) by metal ions Examples thereof include a monomer having a base, a phosphonic acid metal base in which a hydrogen atom of a phosphonic acid group is modified (substituted) with a metal ion, and a sulfinic acid metal base in which a hydrogen atom of a sulfinic acid group is modified (substituted) with a metal ion.

Examples of the monomer in which the hydrogen atom of the hydroxyl group is modified with a metal ion include aryl alcohol, 3-buten-1-ol, 5-hexen-1-ol, 3-methyl-buten-1-ol, citronellol, cinnamyl alcohol, and the like. And those obtained by modifying (substituting) a hydrogen atom of a hydroxyl group.
The modification (substitution) of the metal ion with respect to the hydrogen atom of the hydroxyl group is performed, for example, by adding sodium metal or the like to the alcohol.

Examples of the monomer having a carboxylic acid metal base include those obtained by modifying (substituting) a hydrogen atom of a carboxylic acid group of a monomer such as acrylic acid, methacrylic acid, and 3-butenoic acid with a metal ion.
Examples of the monomer having a sulfonic acid metal base include those obtained by modifying (substituting) a hydrogen atom of a sulfonic acid group of a monomer such as styrene sulfonic acid and allyl sulfonic acid 2-acrylamido-2-methylpropane sulfonic acid with a metal ion. It is done.

  Among these, as a monomer having a metal base, an electron-withdrawing group such as a sulfone group is desirable from the viewpoint that polarization is likely to occur due to high electronegativity.

  On the other hand, as other monomers, acrylic acid, methacrylic acid, alkyl acrylate (for example, ethyl acrylate, ethyl acrylate, n-butyl acrylate, iso-butyl acrylate, 2-ethylhexyl acrylate, isopentyl acrylate, hexyl acrylate, tert-butyl) Acrylate etc.), alkyl methacrylate (eg ethyl methacrylate, ethyl methacrylate, n-butyl methacrylate, iso-butyl methacrylate, 2-ethylhexyl methacrylate, isopentyl acrylate, hexyl acrylate, tert-butyl acrylate etc.), hydroxy acrylate (eg hydroxy Ethyl acrylate, hydroxypropyl acrylate, hydroxybutyl methacrylate, etc.) Hydroxy methacrylate (eg, hydroxyethyl methacrylate, hydroxypropyl methacrylate, hydroxybutyl methacrylate, etc.), alkoxyalkyl acrylate (eg, methoxyethyl acrylate, ethoxyethyl acrylate, butoxyethyl acrylate, phenoxyethyl acrylate, etc.), alkoxyalkyl methacrylate (eg, methoxy Ethyl methacrylate, ethoxyethyl methacrylate, butoxyethyl methacrylate, phenoxyethyl methacrylate, etc.) and alkenes (ethylene, propylene, butene, pentene, etc.).

  Among these, as the other monomer, acrylic acid or methacrylic acid is desirable because the terminal functional group has a large polarization.

  The number of monomer bonds of the ionic oligomer is, for example, about 10 to 100. From the viewpoint of increasing the relative dielectric constant and reducing the leakage current, the number of bonds of the monomer constituting the ionic oligomer is 20 It is preferable that it is 100 or more, desirably 40 or more and 90 or less, and more desirably 60 or more and 85 or less.

  The content of the ionic oligomer is, for example, from 5% to 120%, preferably from 20% to 100%, more preferably from 50% to 80% with respect to the resin.

Next, the resin will be described.
Examples of the resin include (meth) acrylic resin, epoxy resin, alkyd resin, polyurethane resin, polyimide resin, polyamide resin, and the like.
The (meth) acrylic resin means either an acrylic resin or a methacrylic resin, or both.

The resin preferably has a crosslinked structure. Thereby, it is possible to effectively improve the relative permittivity and reduce the leakage current.
In order to impart a crosslinked structure to the resin, for example, 1) A resin having a crosslinkable group (for example, a resin having a monomer having a crosslinkable group such as a hydroxyl group, a carboxyl group, an amino group, an isocyanate group as a polymerization component), This can be realized by using a curing agent (crosslinking agent) that undergoes a crosslinking reaction with the crosslinkable group to cause a crosslinking reaction between the crosslinking group of the monomer and the crosslinking group of the curing agent (crosslinking agent).

Here, examples of the monomer having a crosslinkable group include hydroxyethyl acrylate and the like.
Examples of the curing agent include an isocyanate curing agent and an epoxy curing agent.

As a resin having a cross-linked structure, the relaxation time T ₂ of pulse NMR of the resin having a cross-linked structure is preferably 500 μs at the longest, from the viewpoint of improving the relative dielectric constant and reducing the leakage current. At most 300 μs, more preferably at most 200 μs.
Adjustment of the relaxation time T ₂ of the pulse NMR is performed, for example, by adjusting the resin type and crosslinking agent (hardener) amount.

Incidentally, relaxation time _{T 2} of the pulse NMR, the response signal (free induction decay signals: FID) for the pulse by obtained. If the response signal has a plurality of components, the signal is the sum of the components. Specifically, the FID signal measured using the Solid-Echo method is analyzed by the least square method, and the molecular mobility is low (hard segment) or high using the Gaussian function and Lorentz function. The T _{2H of} (soft segment) and the ratio of each component amount are obtained, and the relaxation time T ₂ is obtained from the following formula (1).
Specifically, T ₂ of the entire resin having a crosslinked structure is T ₂ = (Ma ² T ₂ a + McT ₂ c) / (Ma + Mc) (1)
Can be obtained.
In the formula (1), T ₂ a represents the soft segment relaxation time T _2H (μs). T ₂ c represents a hard segment relaxation time T _2H (μs). Ma represents the ratio (mass ratio) of the component amount of the soft segment. Mc shows the ratio (mass ratio) of the component amount of a hard segment.

  The resin having a crosslinked structure is set to 80 μs or more, more preferably 100 μs or more, even if the relaxation time of pulse NMR is short. This is because if the relaxation time of pulse NMR is short and the hard segment of the resin is too high, the orientation of the metal ions constituting the metal salt structure may be hindered.

  The relaxation time of this pulse NMR is an index indicating the ease of movement of the resin, and the smaller this value, the smaller the degree of freedom of the molecular chain of the resin. In other words, the relaxation time of this pulse NMR is an index indicating the ease of movement of the ionic oligomer, and the smaller this value, the higher the degree of movement restriction of the ionic oligomer and the lower the leakage current. On the other hand, if the relaxation time of this pulse NMR is too small, it means that the degree of freedom of the molecular chain of the resin is too small, the degree of movement restriction of the ionic oligomer is too high, and the capacitance becomes small.

  Here, when a (meth) acrylic resin is applied as the resin having a crosslinked structure, the crosslinking ratio is preferably at least 5% from the viewpoint of improving the relative dielectric constant and reducing the leakage current. Is at least 10%, more desirably at least 20%. Adjustment of this crosslinking ratio is performed by adjusting the number of crosslinkable groups and the addition amount of a hardening | curing agent (crosslinking agent), for example.

The crosslinking ratio of the resin is a value calculated by the formula (limit curing agent amount / used curing agent amount) × 100.
Here, the amount of the limit curing agent is calculated by the number of crosslinkable groups possessed by the resin, and specifically by (weight of crosslinkable group possessed by the resin) / (reactive group ratio possessed by the curing agent).

When a (meth) acrylic resin is applied as a resin having a cross-linked structure, the resin having a cross-linked structure has at least one cross-linkable group per 1000 weight average molecular weight, and a cross-linking reaction of the cross-linkable group ( It is preferable to have a crosslinked structure by a crosslinking reaction between the crosslinking group and the curing agent.
By having the number of crosslinkable groups within the above range, a network structure of an appropriate molecular chain can be formed, the movement of the ionic oligomer can be restricted, the relative permittivity can be improved, and the leakage current can be suppressed. .
The resin to be applied preferably has 1 or more and 10 or less crosslinkable groups, more preferably 1 or more and 3 or less crosslinkable groups per 1000 weight average molecular weight. is there. This is because if the crosslinking ratio (crosslinking point) with respect to the crosslinkable group is too large, the orientation of metal ions constituting the metal salt structure may be hindered.

  The number of crosslinkable groups in the resin is calculated based on the number of equivalents of acid and base reaction that react with the crosslinkable group. Specifically, the amount (weight) of acid or base that reacts per unit weight of the resin Is calculated by

When a (meth) acrylic resin is applied as the resin having a crosslinked structure, the ratio of the crosslinking points to the weight average molecular weight (weight average molecular weight / number of crosslinking points) of the resin having a crosslinked structure is in the range of 100 to 22,000. More preferably, it is the range of 300 or more and 11000 or less, More preferably, it is the range of 350 or more and 5000 or less.
Here, the number of crosslinking points is determined by the number of crosslinkable groups and the crosslinking ratio.

The ratio of the crosslinking point to the weight average molecular weight (weight average molecular weight / number of crosslinking points) is an index indicating the size of the network region of the resin molecular chain. The smaller this value, the more the network of the molecular chain of the resin. The size of the area is reduced.
In other words, the ratio of the crosslinking point to the weight average molecular weight (weight average molecular weight / number of crosslinking points) is an index indicating the size of the migration restricted region of the ionic oligomer, that is, an index indicating the ease of movement of the ionic oligomer. The smaller this value is, the higher the degree of movement restriction of the ionic oligomer is, and the leakage current is reduced.
On the other hand, if the ratio of the crosslinking point to the weight average molecular weight (weight average molecular weight / number of crosslinking points) is too small, it means that the size of the network region of the molecular chain of the resin is too small, which restricts the movement of the ionic oligomer. The degree of is too high and the capacitance becomes small.

Next, a method for manufacturing a dielectric according to the present invention will be described.
The dielectric of the present invention is prepared, for example, by preparing a solution obtained by dissolving a resin (uncrosslinked resin), an ionic oligomer, and, if necessary, other additives such as a curing agent in an organic solvent. For example, it can be applied to a substrate, an electrode, etc.), dried, and heated if necessary.

(Storage battery)
FIG. 1 is a schematic configuration diagram showing an example of the storage battery of the present invention.
As shown in FIG. 1, the storage battery according to the present invention includes a pair of electrodes composed of an upper electrode 11 and a lower electrode 12 disposed to face each other, and a dielectric 10 disposed between the upper electrode 11 and the lower electrode 12. And is composed of.
The dielectric according to the present invention is applied as the dielectric 10.

In the storage battery of the present invention, a pair of electrodes (the upper electrode 11 and the lower electrode 12) is a metal (e.g., gold, silver, copper, nickel, etc.), metal oxides (e.g., SnO2 (tin oxide), _{an In} 2 _{O 3} (Indium oxide), ITO (indium tin oxide), IZO (zinc indium oxide)), or an organic material (for example, polypyrrole or polythiophene) can be used.
In addition, a pair of electrodes (upper electrode 11 and lower electrode 12) in which a conductive film made of the conductive material is formed over a resin substrate can be applied.

The storage battery of the present invention may be a unit obtained by connecting a plurality of units in which a dielectric is disposed between a pair of electrodes (upper electrode 11 and lower electrode 12) in series or in parallel.
The storage battery of this invention can be comprised by shapes, such as a sheet form and the roll shape which wound this, for example.

  The storage battery of the present invention forms, for example, a coating film by applying a coating solution containing the dielectric of the present invention (the high dielectric constant solid material of the present invention) to one of the pair of electrodes (lower electrode 12). Then, the other of the pair of electrodes (the upper electrode 11) is overlaid, and after sandwiching the coating film, the dielectric film 10 can be formed and manufactured by performing a treatment such as drying the coating film. .

Hereinafter, the present invention will be described more specifically with reference to examples. However, these examples do not limit the present invention. Examples 1, 2, 10, and 11 correspond to reference examples.

Example 1
Resin comprising 2-ethylhexyl acrylate / 2-hydroxyethyl acrylate copolymer (polymerization ratio 7: 3, weight average molecular weight 200,000, number of hydroxyl groups 1 [piece / weight average molecular weight 1000]): 100 parts by mass (Sodium ion): 10 parts by mass / solvent (ethyl acetate): 100 parts by mass The above composition was mixed to obtain a dielectric forming coating solution.

  The obtained dielectric forming coating solution was applied onto a 0.2 mm thick copper plate as the lower electrode by a bar coating method so that the thickness after drying was 40 μm, and dried at 110 ° C. for 10 minutes. Then, on the formed coating film, a copper plate having a thickness of 0.2 mm as an upper electrode was pasted, and a capacitor type storage battery (capacitor) in which a dielectric was sandwiched between a pair of electrodes was made as a prototype.

(Example 2)
Resin comprising 2-ethylhexyl acrylate / 2-hydroxyethyl acrylate copolymer (polymerization ratio 7: 3, weight average molecular weight 200,000, number of hydroxyl groups 1 [piece / weight average molecular weight 1000]): 100 parts by mass Oligomer A: 80 parts by mass / solvent (ethyl acetate): 100 parts by mass The above composition was mixed to obtain a coating liquid for forming a dielectric.
Then, a capacitor-type storage battery (capacitor) in which a dielectric was sandwiched between a pair of electrodes was fabricated using the obtained dielectric forming coating solution in the same manner as in Example 1.

Here, the ionic oligomer A was produced as follows.
10 parts by mass of 2-hydroxyethyl acrylate having a lithium salt structure, 20 parts by mass of ethyl acrylate, and 30 parts by mass of 2-ethylhexyl acrylate are added to 50 parts by mass of a solvent (ethyl acetate), and heat treatment is performed at 110 ° C. for 6 hours. Ionic oligomer A was obtained.
The obtained ionic oligomer had 60 monomer bonds and a weight average molecular weight of 8,000.

(Example 3)
Resin comprising 2-ethylhexyl acrylate / 2-hydroxyethyl acrylate copolymer (polymerization ratio 7: 3, weight average molecular weight 200,000, number of hydroxyl groups 1 piece / weight average molecular weight 1000): 100 parts by mass Agent: 0.4 parts by mass / ionic oligomer A: 80 parts by mass / solvent (ethyl acetate): 100 parts by mass The above composition was mixed to obtain a coating liquid for forming a dielectric.
Then, a capacitor-type storage battery (capacitor) in which a dielectric was sandwiched between a pair of electrodes was fabricated using the obtained dielectric forming coating solution in the same manner as in Example 1.

(Examples 4 to 9)
The amount of the isocyanate curing agent is 1 part by mass (Example 4), 4 parts by mass (Example 5), 8 parts by mass (Example 6), 12 parts by mass (Example 7), 16 parts by mass (Example 8). ) And 20 parts by mass (Example 9), respectively, except that the coating liquid for forming a dielectric was obtained in the same manner as in Example 3.
Then, a capacitor-type storage battery (capacitor) in which a dielectric was sandwiched between a pair of electrodes was fabricated using the obtained dielectric forming coating solution in the same manner as in Example 1.

(Example 10)
Resin comprising a bisphenol A / epichlorohydrin copolymer (polymerization ratio 5: 5, weight average molecular weight 8,000): 100 parts by mass Metal ion (sodium ion): 10 parts by mass Solvent (methyl ethyl ketone): 100 parts by mass Part of the above composition was mixed to obtain a dielectric forming coating solution.
Then, a capacitor-type storage battery (capacitor) in which a dielectric was sandwiched between a pair of electrodes was fabricated using the obtained dielectric forming coating solution in the same manner as in Example 1.

(Example 11)
-Resin comprising a bisphenol A / epichlorohydrin copolymer (polymerization ratio 5: 5, weight average molecular weight 8,000): 100 parts by mass-Ionic oligomer A: 80 parts by mass-Solvent (methyl ethyl ketone): 100 parts by mass The composition was mixed to obtain a dielectric forming coating solution.
Then, a capacitor-type storage battery (capacitor) in which a dielectric was sandwiched between a pair of electrodes was fabricated using the obtained dielectric forming coating solution in the same manner as in Example 1.

(Example 12)
-Resin comprising a bisphenol A / epichlorohydrin copolymer (polymerization ratio 5: 5, weight average molecular weight 8,000): 100 parts by mass-Isocyanate curing agent: 0.1 parts by mass-Ionic oligomer A: 80 parts by mass -Solvent (methyl ethyl ketone): 100 mass parts The said composition was mixed and the coating liquid for dielectric formation was obtained.
Then, a capacitor-type storage battery (capacitor) in which a dielectric was sandwiched between a pair of electrodes was fabricated using the obtained dielectric forming coating solution in the same manner as in Example 1.

(Examples 13 to 14)
A dielectric forming coating solution was prepared in the same manner as in Example 12 except that the amount of the isocyanate curing agent was changed to 0.8 parts by mass (Example 13) and 1.2 parts by mass (Example 14), respectively. Obtained.
Then, a capacitor-type storage battery (capacitor) in which a dielectric was sandwiched between a pair of electrodes was fabricated using the obtained dielectric forming coating solution in the same manner as in Example 1.

(Comparative Example 1)
Resin comprising 2-ethylhexyl acrylate / 2-hydroxyethyl acrylate copolymer (polymerization ratio 7: 3, weight average molecular weight 200,000, number of hydroxyl groups 1 [piece / weight average molecular weight 1000]): 100 parts by mass Ethyl acetate): 100 parts by mass The above composition was mixed to obtain a dielectric forming coating solution.
Then, a capacitor-type storage battery (capacitor) in which a dielectric was sandwiched between a pair of electrodes was fabricated using the obtained dielectric forming coating solution in the same manner as in Example 1.

(Evaluation)
-Capacitance (dielectric constant)-
For the capacitor-type storage battery (capacitor) produced in each example, the capacitance was measured under conditions of a frequency of 10 Hz and 10 V using an LCR meter. Then, the relative dielectric constant was calculated based on the measured capacitance.

−Leakage current−
With respect to the capacitor-type storage battery (capacitor) produced in each example, the change in the leakage current value when the value of the electric field strength (applied voltage) was changed was measured. The measurement area was 0.25 cm2.
And in the capacitor type storage battery (capacitor), the maximum value of the leakage current measured in the range of electric field strength of 0 to 1500 V / cm was examined. The maximum value of the leakage current is an average value of nine capacitor type storage batteries (capacitors).

The evaluation results are shown in Table 1 along with the details of the dielectric of the capacitor-type storage battery (capacitor) produced in each example.
FIG. 2 is a graph showing the relationship between the pulse NMR relaxation time of the resin, the capacitance, and the leakage current in Examples 1 to 14 and Comparative Example 1.

The relaxation time T _2H (spin-spin relaxation time) was measured using pulsed NMR. Measurement conditions are: observation nucleus: ¹ H, magnet: permanent magnet 0.85T, detection method: QD method, pulse series: Solid-Echo method, pulse width: 2.0 μs, pulse interval 8.0 μs, pulse repetition time: 3 The measurement temperature was 25 ° C. Hard segment obtained therefrom were determined relaxation time T ₂ in the above equation (1) using T _2H and ratio of the components of the soft segment.

In addition, in the details of the dielectrics in Table 1 (Examples 1 to 9 and Comparative Example 1), the cross-linking ratio (%) of the resin is the amount of limit curing agent of the isocyanate curing agent (Examples 3 to 9) is 21.6. It was a mass part, and it computed based on this.
Further, in the details of the dielectrics in Table 1, the molecular chain network region of the resin (molecular weight of the resin / number of crosslinking points) is the resin in the examples (Examples 1 and 2 and Comparative Example 1) in which the uncrosslinked resin is applied. The molecular weight is shown.

From the above results, it can be seen that Example 1 has a larger capacitance, that is, the relative dielectric constant of the dielectric than the comparative example.
Moreover, in Examples 2-9 and 11-14 which mix | blended the ionic oligomer, it turns out that the leakage current is reduced compared with Examples 1 and 10 which mix | blended the metal ion.
Moreover, in Examples 3-9 and 12-14 which applied crosslinked resin, it turns out that a leakage current is reduced compared with Examples 2 and 11 which applied uncrosslinked resin.

  Specifically, in Comparative Example 1, the leakage current is small and the charge retention characteristic is high, but the capacitance is low because there are no metal ions that cause polarization due to the space charge distribution.

  In Examples 1 and 10, the presence of metal ions that cause polarization due to space charge distribution resulted in a high capacitance.

  In Examples 2 and 11, since the ionic oligomer that causes polarization due to the space charge distribution is more suppressed in the resin than the metal ions, the leakage current is less than in Examples 1 and 10, and the charge is reduced. The retention characteristics of were high.

  In Examples 3 to 9 and 12 to 14, since the cross-linked resin is applied, the movement of the ionic oligomer that causes polarization due to the space charge distribution is limited by the network of the molecular chain of the cross-linked resin. Since the movement within the mesh is ensured, the electrostatic capacity is maintained high, the leakage current is small, and the charge retention characteristic is high.

In Examples 3 to 9 and 12 to 14, the amount of the curing agent is increased, and as the number of crosslinking points of the crosslinked resin increases, ionicity causes polarization due to space charge distribution within the network of the molecular chain of the crosslinked resin. Since the movement of the oligomer is limited, that is, the movable region of the ionic oligomer is narrowed, the leakage current is small and the charge retention property is high.
In particular, in Examples 4 to 9 and 13 to 14, compared with Examples 3 and 12, the relaxation time of pulse NMR is as short as 500 μs or less, and the proportion of hard segments is increased, thereby causing polarization due to space charge distribution. The movement of the ionic oligomer is limited, the leakage current is small, and the charge retention property is high.

In addition, for (meth) acrylic resins, the cross-linking ratio is at least 5%, which restricts the movement of ionic oligomers that cause polarization due to space charge distribution, has little leakage current, and has high charge retention characteristics It became.
In Examples 3 to 9 and 12 to 14, even when the amount of the curing agent is increased, the crosslinking point of the crosslinked resin is increased, and the movable region of the ionic oligomer is narrowed, the ionic oligomer is polarized by the space charge distribution. Since the movement to generate the is secured, the capacitance is maintained high.

10 Dielectric 11 Upper electrode 12 Lower electrode

Claims (5)

A resin having a crosslinked structure ;
A metal ion that is an ionic oligomer having a molecular chain with a metal salt structure ;
A dielectric material comprising The dielectric according to claim 1 , wherein a relaxation time T ₂ of pulse NMR of the resin having a crosslinked structure is 500 μs at the longest. The dielectric according to claim 1 or 2 , wherein the resin having a crosslinked structure is a (meth) acrylic resin, and the crosslinking ratio is at least 5%. The resin having the cross-linked structure is a (meth) acrylic resin, and has at least one crosslinkable group with respect to its weight average molecular weight of 1000, and the cross-linked structure is formed by a cross-linking reaction of at least a part of the crosslinkable group. The dielectric according to any one of claims 1 to 3 . A pair of electrodes;
A dielectric disposed between the pair of electrodes, the dielectric according to any one of claims 1 to 4 ,
A capacitor-type storage battery.

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