Compositions for liquid electrets and liquid electrets

Abstract

To provide a liquid electret composition that can be produced using a readily available material, and to provide a liquid electret that can be easily produced using this liquid electret composition.SOLUTION: The liquid electret 1b is prepared by subjecting a liquid electret composition 1a that contains an organic material (A)3 having a polar group 31, and a non-polar organic material (B)2, and in which the organic material (A)3 is in dispersion state in the organic material (B)2, and has fluidity, preferably fluidity at ordinary temperature range, to a corona discharge treatment or the like to charge a polar group 31 in liquid electret composition 1a.SELECTED DRAWING: Figure 2

Description

Technical Field

[0001] The present invention relates to a composition for a liquid electret and a liquid electret.

Background Art

[0002] Electrets (piezoelectric materials) are applied to acoustic elements, dust collection filters, and the like. However, most of the conventional electrets are in a solid state and have a problem with flexibility.

[0003] Therefore, in order to solve the above problems, liquid organic materials having two or more branched alkyl chains in π-conjugated molecules such as porphyrin derivatives and liquid electrets obtained by charging this liquid organic material have already been proposed (see Patent Document 1 and Non-Patent Document 1). That is, since this liquid electret is in a liquid state at room temperature, it has an advantage that it can be easily deformed into various shapes.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Non-Patent Documents

[0005]

Non-Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0006] However, in the case of the liquid electret proposed above, there are problems that the synthesis of the liquid organic material used as a raw material is somewhat complicated and not easily available, and it is limited to irradiation with negative ions.

[0007] In view of the above circumstances, the present invention aims to provide a liquid electret composition that can be manufactured using readily available materials, and a liquid electret that can be easily produced using this liquid electret composition. [Means for solving the problem]

[0008] To achieve the above objective, the liquid electret composition according to the present invention comprises a polar organic material (A) and a non-polar organic material (B), wherein the organic material (A) is dispersed in the organic material (B) and is fluid. A composition for liquid electrets, wherein the organic material (A) is at least one selected from the group consisting of maleic anhydride-modified polypropylene, ethylene-vinyl acetate copolymer, ethylene-glycidylmethyl acrylate copolymer, ethylene-acrylic acid copolymer, octadecyl succinic anhydride, dioctyl ether, and N,N'-ethylenebisoctadecaneamide. It is characterized by the following. Furthermore, the liquid electret composition according to the present invention , A liquid electret composition comprising a polar organic material (A) and a non-polar organic material (B), wherein the organic material (A) is dispersed in the organic material (B) and is fluid, characterized in that the organic material (B) is at least one selected from the group consisting of alkene polymers, paraffin, and petrolatum.

[0009] The liquid electret composition according to the present invention is easy to handle and can be used in any location. Therefore, it is preferable that it exhibits fluidity in the room temperature range of 10°C to 40°C. However, if the operating temperature range for the liquid electret is outside the room temperature range, the composition may also exhibit fluidity in that operating temperature range. Furthermore, fluidity refers to a degree of deformation that can be achieved without the use of jigs or other fixtures.

[0010] In the present invention, the dispersed state includes the state in which the organic material (A) is uniformly dispersed in the organic material (B), to the extent that its performance as an electret can be ensured, and in which case the organic material (A) is scattered in the organic material (B), which forms a sea, in the form of islands of different sizes.

[0013] The liquid electret composition according to the present invention has a viscosity of 10P or more in the room temperature range of 10°C to 40°C, although this depends on the above operating temperature range (including the temperature when heated for use). 6 It is preferable to set it to P or less. 2 P or more 10 4 It is more preferable to keep it below P. In other words, if the viscosity of the liquid electret composition is too high, it becomes difficult to evenly disperse organic material (A) into organic material (B) during compounding, and problems may arise with the fluidity of the liquid electret composition. Conversely, if the viscosity of the liquid electret composition is too low, the ion conductivity increases, making it difficult to maintain the charged state for a long time, which may cause variability in the function of the liquid electret.

[0014] Furthermore, the liquid electret composition of the present invention may contain additives such as colorants and reinforcing agents, as long as they do not inhibit electrostatic charge.

[0015] The mixing ratio of organic material (A) and organic material (B) is determined appropriately depending on the combination of organic material (A) and organic material (B). It is not particularly limited as long as it exhibits fluidity within the operating temperature range and can function as a liquid electret by being charged. However, it is preferable that the mixing ratio of organic material (A) and organic material (B) be such that the proportion of the polarity-imparting structure of organic material (A) accounts for 0.5 wt% to 2 wt% of the total mixture. In other words, if the proportion of polarity-imparting structures in the mixture is too small, the electret performance will be insufficient, and if it is too large, the electret performance will not improve further, while too much may impair fluidity.

[0016] The method for producing the liquid electret composition of the present invention is not particularly limited, but examples include a method in which organic material (A) and organic material (B) are placed in a stirring tank equipped with a stirring means and stirred and mixed, or a method of kneading in an extruder kneader. Furthermore, for mixing and kneading, it is preferable to heat the organic material (B) to a melted or softened state, and then add the organic material (A) to the organic material (B) while stirring. Furthermore, organic material (A) may be in a molten or softened state before being added to organic material (B).

[0017] The liquid electret of the present invention is characterized in that the organic material (A) in the composition for the liquid electret is in a charged state. Examples of the charging method include a method of subjecting the composition for the liquid electret to a discharge treatment using a corona discharge treatment apparatus or the like, and a method of supplying ions using a static eliminator (ionizer). As the static eliminator, for example, a small-sized one such as a portable static eliminator (EST-M) manufactured by Ishiyama Seisakusho Co., Ltd. can be used.

Advantages of the Invention

[0018] As described above, the composition for the liquid electret according to the present invention contains a polar organic material (A) and a non-polar organic material (B), and the organic material (A) is in a dispersed state in the organic material (B) and has fluidity. That is, since it has fluidity, it can be easily deformed into various shapes, and it is only necessary to disperse at least the organic material (A) in the organic material (B), so it can be easily manufactured. Also, as the organic material (A) and the organic material (B), general-purpose materials or organic materials that are easy to synthesize even if newly synthesized can be used to reduce costs. Then, by charging the polarity-imparting structural part of the organic material (A) in the composition for the liquid electret by supplying ions using a discharge treatment or a static eliminator, a liquid electret with fluidity can be easily obtained.

Brief Description of the Drawings

[0019] [Figure 1] It is a diagram schematically showing the mixed state of the organic material (A) and the organic material (B) of the composition for the liquid electret according to the present invention. [Figure 2] It is a diagram schematically showing the liquid electret obtained by charging the composition for the liquid electret of FIG. 1. [Figure 3]This graph compares the time evolution of the surface potential of liquid electret composition a prepared in Experiment 1, polybutene, and maleic anhydride-modified polypropylene after they have been charged. [Figure 4] This graph compares the time evolution of the surface potential of liquid electret composition a prepared in Experiment 1, polypropylene, and polytetrafluoroethylene after they have been charged. [Figure 5] This diagram schematically shows a measuring device for measuring the piezoelectric performance of liquid electret a obtained by charging the liquid electret composition a prepared in Experiment 1. [Figure 6] This graph shows the time course of the voltage generated by liquid electret a, measured with the measuring device in Figure 5, in comparison with that of a solid electret made of charged polytetrafluoroethylene. [Figure 7] This graph compares the change in viscosity of polybutene with temperature between liquid electret composition a, prepared in Experiment 1, a comparative composition, and the liquid electret composition a. [Figure 8] This graph shows the time evolution of the surface potential when a comparative composition was subjected to corona discharge treatment under the same conditions as liquid electret composition a in Experiment 1, in comparison with liquid electret composition a in Experiment 1. [Figure 9] This graph shows the time evolution of the surface potential when liquid electret composition b and liquid electret composition c, obtained in Experiment 4, were subjected to corona discharge, in comparison with liquid electret composition a from Experiment 1. [Figure 10] This graph shows the time evolution of the surface potential of liquid electret composition d, electret composition e, and liquid electret composition f obtained in Experiment 5 after corona discharge treatment, in comparison with liquid electret composition a from Experiment 1. [Figure 11]This graph shows the results of treating each of the liquid electret compositions g, h, i, and x obtained in Experiments 6-8 with corona discharge under the same conditions as liquid electret composition a in Experiment 1, and then examining the time evolution of their surface potential. [Figure 12] This graph shows the relationship between the viscosity of a liquid electret and its charge relaxation time. [Figure 13] This graph shows the time-dependent change in surface potential of liquid electret composition a when it is charged by emitting positive ions using a portable static eliminator (EST-M), compared with that of polybutene. [Figure 14] This graph shows the time-dependent change in surface potential when a liquid electret composition (o) using petrolatum as the organic material (B) is charged, compared to the case of petrolatum alone. [Modes for carrying out the invention]

[0020] The present invention will be described in detail below with reference to the drawings. Figure 1 schematically shows the mixed state of organic material (A) and organic material (B) of the liquid electret composition according to the present invention, and Figure 2 schematically shows the state in which the liquid electret composition according to the present invention is charged to become a liquid electret.

[0021] As shown in Figure 1, this liquid electret composition 1a is a dispersion mixture in which an organic material (A) 3 having a polar group 31 as a polarity-imparting structure in its molecule and a non-polar organic material (B) 2 are dispersed with the organic material (A) 3 interposed between the organic materials (B) 2. It is preferable that organic material (A)3 is uniformly dispersed in organic material (B)2 at the molecular level, but it may also be dispersed in an island-like manner within organic material (B)2, where multiple molecules aggregate to form a sea.

[0022] The organic material (A) is not particularly limited as long as it has polarity, can be well dispersed and mixed in the organic material (B), and can yield a liquid electret composition that exhibits fluidity within the operating temperature range. Examples include materials that have a polarity-imparting structure selected from the group consisting of acid anhydride structures, ester structures, carboxylic acid structures, ether structures, and amide structures in their molecules, such as maleic anhydride-modified polypropylene, ethylene-vinyl acetate copolymer, ethylene-glycidylmethyl acrylate copolymer, ethylene-acrylic acid copolymer, octadecyl succinic anhydride, dioctyl ether, and N,N'-ethylenebisoctadecaneamide.

[0023] The organic material (B) is not particularly limited as long as it is nonpolar and fluid within the operating temperature range, but examples include low molecular weight alkene polymers also called oligomers, copolymers of two or more alkenes and α-olefins and mixtures thereof, paraffin, petrolatum, etc., and it is preferable that it is fluid in the room temperature range of 10°C to 40°C.

[0024] Furthermore, although not shown in the figures, by, for example, discharging the liquid electret composition 1a using a discharge processing device, or by radiating positive ions onto the liquid electret composition 1a using a portable static eliminator, a liquid electret 1b in which the polar groups 31 of the liquid electret composition 1b are positively charged can be obtained, as shown in Figure 2.

[0025] The present invention will be described in detail below with reference to specific experiments.

[0026] (Experiment 1) As organic material (B), polybutene represented by the following formula 1 (number average molecular weight Mn = ~920, viscosity at 100°C 2P, isobutylene 90% or more) was placed in a container and stirred with a hot magnetic stirrer at 150~200°C. Then, as organic material (A), solid maleic anhydride-modified polypropylene represented by the following formula 2 (weight average molecular weight Mw = ~9100, number average molecular weight Mn = ~3900, maleic anhydride groups 8~10 wt%) was added in a proportion of 10 wt% of the total (the concentration of maleic anhydride groups, which are the polarity-imparting structural part, corresponds to approximately 1 wt%). After stirring for 1 hour, a transparent liquid electret composition a with a syrup-like fluidity at room temperature was obtained.

[0027] [ka]

[0028] [ka]

[0029] The liquid electret composition a obtained as described above was subjected to a corona discharge device (G-90P, manufactured by Green Techno Co., Ltd.) at +20kV for 30 seconds to obtain the liquid electret a of the present invention. The surface potential of the obtained liquid electret a, the polybutene (PB) charged under the above discharge conditions, and the maleic anhydride-modified polypropylene (MPP) was measured after discharge for up to 2 hours using an electrostatic meter (ASPURE, YC-102), and the results are shown in Figure 3. Furthermore, under the same conditions as described above, polypropylene (PP, Mw=12,000, Mn=5,000) and polytetrafluoroethylene (PTFE sheet with a thickness of 0.05 mm (Nichias Corporation's product name TOMBO No. 9001)), which are used as solid electrets, were charged, and the time change of the surface potential up to 8 days was measured. The results are shown in Figure 4 in comparison with composition a for liquid electrets. In Figures 3 and 4, PB / MPP represents liquid electret a.

[0030] Figure 3 shows that the liquid electret a has a similar level of chargeability to that of a solid MPP. Figure 4 shows that the electrostatic properties of the liquid electret a are not significantly different from those of PP and PTFE. In other words, Figures 3 and 4 show that the liquid electret a obtained by charging liquid electret composition a is fully usable as an electret.

[0031] (Experiment 2) As shown in Figure 5, a liquid electret a is placed on the lower metal electrode plate 5, and the upper metal electrode plate 6 is positioned so as to not contact the liquid electret a and to maintain a constant distance between it and the lower metal electrode plate 5. Then, when a 10g plastic ball 7 was dropped from a position 10cm above the upper metal electrode plate 6, the voltage generated by the change in distance between the two electrode plates 5 and 6 was repeatedly examined at intervals. Similarly, with the PTFE solid electret used in Experiment 1 placed between the metal electrode plates 5 and 6 instead of the liquid electret a, a 10g plastic sphere 7 was dropped from a position 10cm above the upper metal electrode plate 6, just as with the liquid electret a. The voltage generated by the change in distance between the two electrode plates 5 and 6 was repeatedly investigated over time, and the results are shown in comparison in Figure 6. Figure 6 shows that liquid electret a can maintain equivalent or superior piezoelectricity over a long period compared to solid electret. In Figure 6, piezo PB / MPP represents liquid electret a, and piezo PTFE represents solid electret.

[0032] (Experiment 3) A comparative composition was obtained by mixing the polypropylene used in Experiment 1 with the same weight ratio as the maleic anhydride-modified polypropylene used in liquid electret composition a, which was used in Experiment 1. The temperature dependence of the viscosity of liquid electret composition a, the comparative composition described above, and polybutene was measured, and the results are shown in comparison in Figure 7. Furthermore, Figure 8 shows the time evolution of the surface potential when the comparative composition was subjected to corona discharge treatment under the same conditions as liquid electret composition a in Experiment 1, in comparison with liquid electret composition a in Experiment 1. In Figures 7 and 8, PB represents polybutene, PB / MPP represents composition a for liquid electrets, and PB / PP represents the comparative composition. Figure 7 shows that when polybutene is mixed with maleic anhydride-modified polypropylene, the viscosity increases compared to polybutene alone, and when polypropylene is added, the viscosity increases even further. On the other hand, Figure 8 shows that simply mixing polybutene with a nonpolar organic material to increase viscosity does not produce an electret.

[0033] (Experiment 4) Composition b for liquid electrets, in which maleic anhydride-modified polypropylene was blended at a ratio of 5 wt% (equivalent to a maleic anhydride group concentration of approximately 0.5 wt%), and composition c for liquid electrets, in which maleic anhydride-modified polypropylene was blended at a ratio of 20 wt% (equivalent to a maleic anhydride group concentration of approximately 2 wt%), were prepared in the same manner as for composition a for liquid electrets. Then, under the same conditions as for liquid electret composition a, the time evolution of the surface potential of liquid electret composition b and liquid electret composition c when subjected to corona discharge treatment was investigated and shown in comparison with the results for liquid electret composition a in Figure 9. In Figure 9, PB represents polybutene, PB / MPP(10wt%) represents liquid electret composition a, PB / MPP(5wt%) represents liquid electret composition b, and PB / MPP(20wt%) represents liquid electret composition c. Figure 9 shows that if the proportion of maleic anhydride-modified polypropylene is too low, the electret performance is insufficient, and if the proportion is too high, the electret performance does not improve beyond a certain point. In other words, the appropriate mixing ratio of organic material (A) needs to be determined appropriately for each combination of organic material (A) and organic material (B).

[0034] (Experiment 5) In the same polybutene mixture as in Experiment 1, instead of maleic anhydride-modified polypropylene, the following ethylene-vinyl acetate copolymer (manufactured by Sigma-Aldrich, vinyl acetate group content in the molecule 12 wt%, melt index 8 g / 10 min (190°C / 2.16 kg)), ethylene-glycidyl methacrylate copolymer (manufactured by Sigma-Aldrich, glycidyl methacrylate group content in the molecule 8 wt%, melt index 5 g / 10 min (190°C / 2.16 kg)), and ethylene-acrylic acid copolymer (manufactured by Sigma-Aldrich, acrylic acid group content in the molecule 5 wt%) were dispersed and mixed in such a proportion that the polar group portion, which is the polarity-imparting structure, accounts for 1 wt% of the total, to obtain liquid electret compositions d, e, and f, which are fluid at room temperature, as organic material (A). Then, each of the obtained liquid electret compositions d, e, and f was charged in the same manner as liquid electret composition a, and the time change of the surface potential was investigated. The results are shown in comparison in Figure 10. In Figure 10, PB / PEV represents liquid electret composition d, PB / PEG represents liquid electret composition e, and PB / PEA represents liquid electret composition f. Figure 10 shows that by mixing an organic material (A) with a polar group with a non-polar organic material (B), a liquid electret composition can be obtained.

[0035] [ka]

[0036] [ka]

[0037] [ka]

[0038] (Experiment 6) As organic material (B), instead of the polybutene used in Experiment 1, a mixed material x (viscosity 1.4 × 10 at 25°C) was prepared by mixing high-viscosity polybutene (number-average molecular weight Mn = ~2300, viscosity 40P at 99°C) and polypropylene (Mw = 12,000, Mn = 5,000) so that the proportion of polypropylene was 10 wt%. 5 Using P), and except that octadecyl succinic anhydride shown in the following formula 6 was blended as the organic material (A) in an amount of 1 wt%, a liquid electret composition g that is fluid at room temperature was obtained in the same manner as in Experiment 1.

[0039] [ka]

[0040] (Experiment 7) A liquid electret composition h having fluidity at room temperature was obtained in the same manner as in Experiment 6, except that the above mixed material x was used as organic material (B), and dioctyl ether shown in the following formula 7 was blended as organic material (A) in an amount of 1 wt%.

[0041] [ka]

[0042] (Experiment 8) A liquid electret composition i that is fluid at room temperature was obtained in the same manner as in Experiment 6, except that the above mixed material x was used as organic material (B), and N,N'-ethylenebisoctadecaneamide shown in the following formula 8 was blended as organic material (A) in an amount of 1 wt%.

[0043] [ka]

[0044] Each of the liquid electret compositions g, h, i, and x obtained in Experiments 6 to 8 above was subjected to corona discharge treatment under the same conditions as liquid electret composition a in Experiment 1. The time evolution of the surface potential was then investigated, and the results are shown in comparison in Figure 11. Figure 11 shows that if organic material (B) has a reasonably high viscosity, then organic material (A) can be low molecular weight without any problems. In Figure 11, PBh / PP represents mixed material x, PBh / PP+ODSA represents liquid electret composition g, PBh / PP+DOE represents liquid electret composition h, and PBh / PP+EBOA represents liquid electret composition i.

[0045] (Experiment 9) As the organic material (B), paraffin (viscosity 0.3P at 25°C) was used, and maleic anhydride-modified polypropylene used in Experiment 1 was mixed with this paraffin in the same manner as in Experiment 1 to obtain a liquid electret composition j that is fluid at room temperature.

[0046] (Experiment 10) As the organic material (B), a mixture a (viscosity 5P at 25°C) was used, which consisted of polybutene used in Experiment 1 and the paraffin in a weight ratio of 5:5. Maleic anhydride-modified polypropylene used in Experiment 1 was mixed into this mixture a in the same manner as in Experiment 1 to a proportion of 10 wt%, thereby obtaining a liquid electret composition k that is fluid at room temperature.

[0047] (Experiment 11) As the organic material (B), a mixture b (viscosity 70P at 25°C) was obtained by mixing the polybutene used in Experiment 1 and the paraffin in a weight ratio of 8:2. Maleic anhydride-modified polypropylene used in Experiment 1 was mixed into this mixture b in the same manner as in Experiment 1 to a proportion of 10 wt%, thereby obtaining a liquid electret composition l that is fluid at room temperature.

[0048] (Experiment 12) High-viscosity polybutene (viscosity 40P at 99°C) was used as the organic material (B). Maleic anhydride-modified polypropylene used in Experiment 1 was mixed with this high-viscosity polybutene in the same manner as in Experiment 1, at a ratio of 10 wt%, to obtain a liquid electret composition m that is fluid at room temperature.

[0049] (Experiment 13) As organic material (B), a mixture c (viscosity 5P at 25°C) was obtained by mixing high-viscosity polybutene (viscosity 40P at 99°C) and the polybutene used in Experiment 1 in a weight ratio of 5:5. Maleic anhydride-modified polypropylene used in Experiment 1 was mixed into this mixture c in the same manner as in Experiment 1 to a proportion of 10 wt%, thereby obtaining a liquid electret composition n that is fluid at room temperature.

[0050] (Experiment 14) After charging each of the liquid electret compositions a, j, and n obtained in Experiments 1 and 9-13 in the same manner as in Experiment 1, the time until the charged state was relaxed (relaxation time (charge maintenance time ≈ time until it can no longer be used as an electret)) was determined for each, and the results are shown in comparison in Figure 12. In Figure 12, PB represents polybutene, MPP represents maleic anhydride-modified polypropylene, and PBh represents high-viscosity polybutene. From Figure 12, it can be seen that as the viscosity of the liquid electret composition increases, the relaxation time increases, but 10 3 It can be seen that the relaxation time levels off once P is exceeded. In this invention, since the fluid being measured is a non-Newtonian fluid, viscosity was determined by extrapolation at a rotational speed of 10 rpm, and the viscosity at room temperature (25°C) was also determined by extrapolation from the viscosity at high temperature.

[0051] (Experiment 15) Composition a for the liquid electret used in Experiment 1 and polybutene similar to that used in Experiment 1 were each positively charged by emitting positive ions using a portable static eliminator (EST-M) from Ishiyama Seisakusho Co., Ltd., and then the time change of the surface potential was investigated, and the results are shown in Figure 13. Figure 13 shows that the liquid electret composition of the present invention can become charged and form a liquid electret simply by emitting positive ions using a portable static eliminator with a piezoelectric element that does not require electricity supplied from a power source, without the need for a large-scale corona discharge device. In other words, if the amount of static charge decreases, it can be easily restored to its original level using a portable static eliminator like the one described above.

[0052] (Experiment 16) A liquid electret composition o was obtained in the same manner as in Experiment 1, except that petrolatum (viscosity 0.6P at 25°C) was used as the organic material (B) in place of polybutene in Experiment 1. The obtained liquid electret composition o was charged in the same manner as in Experiment 1, and the results are shown in comparison with the case of petrolatum alone in Figure 14. Figure 14 shows that by using petrolatum as a nonpolar organic material (B) and combining it with an organic material (A) that has effective polarity, a liquid electret composition useful for the fabrication of liquid electrets can be produced.

[0053] From experiments 1 to 16 above, it can be seen that, as in the present invention, a liquid electret composition can be easily obtained simply by mixing a general-purpose organic material (A) with a general-purpose organic material (B). Furthermore, it can be seen that a liquid electret can be easily obtained by charging the liquid electret composition of the present invention.

[0054] The present invention is not limited to the experimental examples described above. In the experimental examples described above, the material was made to be positively charged, but it is also possible to make it negatively charged by changing the structure of the part that imparts polarity to the organic material (A). [Explanation of symbols]

[0055] 1a Composition for liquid electrets 1b Liquid electret 2 Organic materials (B) 3 Organic materials (A) 31 Polar group 5. Lower metal electrode plate 6. Upper metal electrode plate 7 Plastic balls

Claims

1. A liquid electret composition comprising a polar organic material (A) and a non-polar organic material (B), wherein the organic material (A) is dispersed in the organic material (B) and is fluid, characterized in that the organic material (A) is at least one selected from the group consisting of maleic anhydride-modified polypropylene, ethylene-vinyl acetate copolymer, ethylene-glycidylmethyl acrylate copolymer, ethylene-acrylic acid copolymer, octadecyl succinic anhydride, dioctyl ether, and N,N'-ethylenebisoctadecaneamide.

2. A liquid electret composition comprising a polar organic material (A) and a non-polar organic material (B), wherein the organic material (A) is dispersed in the organic material (B) and is fluid, characterized in that the organic material (B) is at least one selected from the group consisting of alkene polymers, paraffin, and petrolatum.

3. The liquid electret composition according to claim 1 or claim 2, which exhibits fluidity at 10°C to 40°C.

4. The liquid electret composition according to any one of Claims 1 to 3, wherein the viscosity is 10 P or more and 10 6 P or less in the operating temperature range.

5. A liquid electret characterized in that the organic material (A) in the liquid electret composition according to any one of Claims 1 to 4 is in a charged state.

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