JP5479878B2 - Electrolytic capacitor - Google Patents

Description

  The present invention relates to an electrolytic capacitor.

  Electrolytic capacitors have the characteristics of small size, large capacity, and low cost, and are widely used as one of important components such as electronic devices, electric devices, and on-vehicle devices. An electrolytic capacitor comprises an anode foil having an anodized film on the surface, a cathode foil, and a separator, and a capacitor element obtained by winding these with a separator interposed between the anode foil and the cathode foil. It has a structure formed by being immersed in an electrolytic solution.

  In such an electrolytic capacitor, the separator is mainly used for the purpose of ensuring the separation between the anode foil and the cathode foil. Cellulose paper is generally used as the separator, but conventionally, for example, heat-resistant flame retardant paper made of aromatic polyaramid fiber, aromatic polyamide fiber, polyphenylene sulfide, etc. has been used. (For example, refer patent documents 1-3.).

  According to the conventional electrolytic capacitor, since a heat-resistant flame retardant paper made of aromatic polyaramid fiber, aromatic polyamide fiber, polyphenylene sulfide, etc. is used as a separator, high flame resistance, high tensile strength, chemical resistance, Excellent capacitor characteristics (capacitance characteristics, dielectric loss tangent characteristics and leakage current characteristics) are obtained.

JP-A-1-278713 JP-A-2-20012 Japanese Patent Laid-Open No. 2-126622

  In recent years, further environmental resistance is required in electronic devices, electric devices, vehicle-mounted devices, and the like. Electrolytic capacitors mounted on these devices are also required to have high safety, particularly high flame retardance, while exhibiting sufficient performance even when used in harsh environments. ing.

  Then, this invention is made | formed in view of an above-described situation, Comprising: It aims at providing the electrolytic capacitor which was further excellent in the flame retardance than before.

[1] The electrolytic capacitor of the present invention includes an anode foil having an anodized film on the surface, a cathode foil, and a separator, and the separator is interposed between the anode foil and the cathode foil. An electrolytic capacitor having a structure in which a capacitor element obtained by winding an anode foil, the cathode foil, and the separator is immersed in an electrolytic solution, wherein the separator includes at least an amorphous polyetherimide fiber. It consists of a flame-retardant paper.

  According to the present invention, as can be seen from an example (Example 2) which will be described later, it is possible to provide an electrolytic capacitor which is more excellent in flame retardancy than before.

Further, according to the present invention, the following effects can also be obtained. That is, it is known that the content of water and boric acid in the electrolytic solution may be increased in order to increase the flame retardance of the electrolytic capacitor. However, when the content of water and boric acid in the electrolytic solution is increased, the cellulose fibers contained in the cellulose paper generally used as a separator are easily broken, so that the separator is easily broken and the pressure when an abnormal voltage is applied is increased. The problem that durability falls and the problem that the long-term reliability of an electrolytic capacitor falls newly generate | occur | produces. In addition, when the cellulose fiber is easily broken, the separator using the cellulose fiber is more easily combusted, so that the flame retardancy cannot be increased as expected.
On the other hand, according to the present invention, as can be seen from the examples (Example 2) described later, even if the contents of water and boric acid in the electrolytic solution are increased, the fibers constituting the heat-resistant flame retardant paper Since it is difficult for the unraveling to occur, the separator easily breaks and the durability against pressure at the time of abnormal voltage application is reduced, and the long-term reliability of the electrolytic capacitor is reduced. The flame retardance of the electrolytic capacitor can be increased.

[2] In the electrolytic capacitor of the present invention, it is preferable that the heat-resistant flame retardant paper contains 30% by weight to 90% by weight of amorphous polyetherimide fiber.

  When the content of the amorphous polyetherimide fiber is less than 30% by weight, the effect of improving flame retardancy may not be obtained. On the other hand, when the content of the amorphous polyetherimide fiber exceeds 90% by weight, the amorphous polyetherimide fiber has properties that are difficult to make into paper originally, so the formability in the papermaking process is reduced. To do.

[3] In the electrolytic capacitor of the present invention, it is preferable that the electrolytic solution contains 5 to 15% by weight of water and 5 to 35% by weight of boric acid.

  When the water content is less than 5% by weight, the effect of improving flame retardancy may not be obtained. On the other hand, when the water content exceeds 15% by weight, the aluminum foil constituting the anode foil and the cathode foil may be easily deteriorated, or the corrosion resistance of the anode-side constituent member may be lowered. . From these viewpoints, the water content is preferably in the range of 7 wt% to 13 wt%.

  When the content of boric acid is less than 5% by weight, the effect of improving flame retardancy may not be obtained. On the other hand, when the content of boric acid exceeds 35% by weight, it becomes difficult to sufficiently impregnate the electrolytic solution into the capacitor element due to the viscosity of the electrolytic solution becoming too high, which is necessary as an electrolytic capacitor. There may be a problem that performance may not be obtained. From these viewpoints, the boric acid content is preferably in the range of 10 wt% to 20 wt%.

In the electrolytic capacitor of [4] The present invention, the density of the separator ^is preferably in the range of ^{0.25g / cm 3 ~0.95g / cm 3} .

When the density of the separator is less than 0.25 g / cm ³ , the separator performance such as heat resistance, insulating properties, and withstand voltage characteristics may be deteriorated. From this point of view, the density of the separator is more preferably 0.50 g / cm ³ or more, and further preferably 0.60 g / cm ³ or more. On the other hand, when the density of the separator exceeds 0.95 g / cm ³ , the performance of the electrolytic capacitor such as tan δ (loss angle tangent) characteristic, ESR (equivalent series resistance) characteristic, and life may deteriorate. From this viewpoint, the density of the separator is more preferably 0.90 g / cm ³ or less, and further preferably 0.85 g / cm ³ or less.

[5] In the electrolytic capacitor of the present invention, the amorphous polyetherimide fiber is formed from an amorphous polyetherimide polymer having a molecular weight distribution (Mw / Mn) of less than 2.5. It is preferable.

  By using an amorphous polyetherimide-based polymer having a specific molecular weight distribution as in the present invention, it is not only excellent in flame retardancy but also low smoke generation, flexibility, and low temperature shrinkage. -Based polyetherimide fiber can be produced.

[6] In the electrolytic capacitor of the present invention, the heat resistant flame retardant paper includes at least a heat resistant fiber other than the amorphous polyetherimide fiber in addition to the amorphous polyetherimide fiber. Is preferred.

  Thus, in addition to the amorphous polyetherimide fiber, when including at least a heat resistant fiber other than the amorphous polyetherimide fiber, the moldability in the papermaking process is improved and the heat resistance is improved. There is an effect that the fibers contained in the flame retardant paper are difficult to break.

  From this point of view, in the electrolytic capacitor of the present invention, in addition to the amorphous polyetherimide fiber and the heat resistant fiber other than the amorphous polyetherimide fiber, the electrolytic capacitor has flame retardancy and heat resistance. It is preferable that the binder fiber of the kind and quantity which do not reduce the characteristic as is included.

  Examples of heat-resistant fibers other than amorphous polyetherimide fibers include polyarylate fibers, polyphenylene sulfide fibers, glass fibers, paraamide fibers, cellulose fibers, and polysulfonamides as shown in Examples (Example 1) described later. Organic or inorganic fibers such as fibers can be preferably used.

  As a binder fiber, as shown in the Example (Example 1) mentioned later, organic fibers, such as a polyethylene terephthalate fiber and a polyvinyl alcohol fiber, can be used preferably.

[7] In the electrolytic capacitor of the present invention, the heat-resistant fiber preferably has a melting point or a thermal decomposition temperature of 200 ° C. or higher.

  By comprising in this way, it becomes possible to ensure the heat resistance as the whole heat-resistant flame-retardant paper.

[8] In the electrolytic capacitor of the present invention, the weight ratio of the amorphous polyetherimide fiber to the heat resistant fiber is preferably 30/70 to 98/2.

  By comprising in this way, "flame retardance", "formability in a papermaking process", and "the difficulty of unraveling fibers contained in heat resistant flame retardant paper" can be improved in a balanced manner.

[9] In the electrolytic capacitor of the present invention, the ratio of the total weight of the amorphous polyetherimide fiber and the heat resistant fiber to the total weight of the heat resistant flame retardant paper is 50% or more. It is preferable that

  By comprising in this way, "flame retardance", "formability in a papermaking process", and "the difficulty of unraveling fibers contained in heat resistant flame retardant paper" can be improved in a balanced manner.

[10] In the electrolytic capacitor of the present invention, it is preferable that the carbonization length of the heat-resistant flame retardant paper is 15.0 cm or less as measured using “JIS L1091 A-4 method”.

  Thus, when the carbonization length of the heat resistant flame retardant paper is 15.0 cm or less, predetermined flame retardancy can be ensured.

[11] In the electrolytic capacitor of the present invention, the heat-resistant flame retardant paper preferably has a dry heat shrinkage at 200 ° C. of 4.0% or less.

  Thus, when the heat-resistant flame retardant paper has a dry heat shrinkage at 200 ° C. of 4.0% or less, the long-term reliability of the electrolytic capacitor can be increased.

[12] In the electrolytic capacitor of the present invention, it is preferable that an equilibrium moisture content of the heat-resistant flame retardant paper is 3.0% or less.

  Thus, when the equilibrium moisture content of the heat-resistant flame retardant paper is 3.0% or less, the amount of water contained in the electrolytic solution can be precisely controlled.

[13] In the electrolytic capacitor of the present invention, the heat-resistant fiber is preferably composed of at least one selected from the group consisting of wholly aromatic polyester fibers, glass fibers, and polysulfonamide fibers.

  By comprising in this way, "flame retardance", "formability in a papermaking process", and "the difficulty of unraveling fibers contained in heat resistant flame retardant paper" can be improved in a balanced manner.

[14] In the electrolytic capacitor of the present invention, the heat-resistant fiber is preferably composed of a melt-anisotropic wholly aromatic polyester fiber.

  By comprising in this way, "flame retardance", "formability in a papermaking process", and "the difficulty of unraveling fibers contained in heat resistant flame retardant paper" can be improved in a balanced manner.

It is a figure shown in order to demonstrate the electrolytic capacitor which concerns on embodiment. FIG. 4 is a diagram showing evaluation results of test examples in Example 1. FIG. 6 is a diagram showing the evaluation results of each test example in Example 2. FIG. 10 is a diagram showing the evaluation results of each test example in Example 3.

  Hereinafter, the electrolytic capacitor of the present invention will be described in more detail based on the embodiments shown in the drawings.

1. Configuration of electrolytic capacitor 100 according to the embodiment
1-1. Overall Configuration FIG. 1 is a diagram for explaining an electrolytic capacitor 100 according to an embodiment. 1A is a diagram showing the structure of the capacitor element 110, FIG. 1B is an exploded perspective view of the electrolytic capacitor 100, and FIG. 1C is a perspective view of the electrolytic capacitor 100. FIG.

  As shown in FIG. 1, the electrolytic capacitor 100 according to the embodiment includes an anode foil 120 having an anodized film on the surface, a cathode foil 130, and a separator 140, and the anode foil 120 and the cathode foil 130 are between them. Capacitor element 110 (see FIG. 1A) obtained by winding anode foil 120, cathode foil 130, and separator 140 with separator 140 interposed therebetween was placed in bottomed cylindrical metal case 180. It has a structure formed by immersing it in an electrolytic solution (not shown) (see FIGS. 1B and 1C).

  In the electrolytic capacitor 100 according to the embodiment, the anode side external lead terminal 150 connected to the anode foil 120 and the cathode side external lead terminal 160 connected to the cathode foil 130 are inserted into each external lead terminal insertion hole of the elastic sealing body 170. Then, the capacitor element 110 and the elastic sealing body 170 are integrated (see FIG. 1B), and then the capacitor element 110 is inserted into the bottomed cylindrical metal case 180 in a state impregnated with the electrolytic solution. Then, it can be manufactured by winding the metal case 180 around the elastic sealing member 170 (see FIG. 1C).

1-2. The heat-resistant flame retardant paper constituting the heat-resistant flame retardant paper separator 140 includes amorphous polyetherimide fibers (A), polyarylate fibers (PAR fibers) as heat resistant fibers (B), and binder fibers ( And polyethylene terephthalate fiber (PET fiber) as C). This heat resistant flame retardant paper is basically the same heat resistant flame retardant paper as the heat resistant flame retardant paper shown in Test Example 1 of FIG. However, only the basis weight is changed to 50 g / m ² .
In the following, amorphous polyetherimide is abbreviated as amorphous PEI. Polyarylate is abbreviated as PAR. In addition, polyethylene terephthalate is abbreviated as PET.

  The amorphous PEI fiber is formed from an amorphous PEI polymer having a molecular weight distribution (Mw / Mn) of less than 2.5. The PAR fiber is an organic heat-resistant fiber classified as a wholly aromatic polyester fiber, and the thermal decomposition temperature of the PAR fiber is 400 ° C. or higher.

  The weight ratio of the amorphous PEI fiber (A) to the heat resistant fiber (B) (hereinafter referred to as parameter D) is 30/45, and the amorphous PEI fiber relative to the total weight of the heat resistant flame retardant paper ( The ratio of the total weight of A) and the heat-resistant fiber (B) (hereinafter referred to as parameter E) is 75%.

The basis weight of the heat resistant flame retardant paper is 50 g / m ² as described above, and the thickness of the heat resistant flame retardant paper is 0.07 mm (70 μm). 0.72 g / cm ³ . Further, the carbonization length of the heat-resistant flame retardant paper measured by using “JIS L1091 A-4 method” is 3.0 cm, and “the heat-resistant flame retardant paper has a dry heat shrinkage ratio at 200 ° C. of 0. 0. The equilibrium moisture content of the heat-resistant flame retardant paper is 0.2%.

1-3. The electrolytic solution used in the electrolytic capacitor 100 according to the electrolytic solution is an electrolytic solution in which 20 wt% boric acid as a solute and other electrolytes are dissolved in a solvent containing 50 wt% ethylene glycol and 10 wt% water. (Refer to Test Example 23 in FIG. 3).

1-4. Details of heat-resistant flame retardant paper The heat-resistant flame retardant paper is described in detail below.

(Amorphous PEI fiber)
The amorphous PEI fiber used in the present invention is formed from an amorphous PEI polymer having a specific molecular weight distribution. By using such a polymer, it is possible to improve the spinnability from the amorphous PEI polymer and to obtain amorphous PEI fiber having small single yarn fineness suitable for paper use. And the obtained amorphous PEI fiber can improve the workability in the paper-making process performed next, and can improve the flame retardance.

(Amorphous PEI polymer)
The amorphous PEI polymer will be described. The amorphous PEI polymer used in the present invention is a polymer containing an aliphatic, alicyclic or aromatic ether unit and a cyclic imide as repeating units, and has amorphous and melt moldability. If it is, it will not specifically limit. Moreover, within the range that does not inhibit the effect of the present invention, the structural unit other than cyclic imide and ether bond, such as aliphatic, alicyclic or aromatic ester unit, oxycarbonyl unit, etc. It may be contained.

Specifically, as the amorphous PEI polymer, a polymer having a unit represented by the following general formula is preferably used. Where R ¹ is a divalent aromatic residue having 6 to 30 carbon atoms, R ² is a divalent aromatic residue having 6 to 30 carbon atoms, Selected from the group consisting of alkylene groups having 20 carbon atoms, cycloalkylene groups having 2 to 20 carbon atoms, and polydiorganosiloxane groups chain-terminated with alkylene groups having 2 to 8 carbon atoms. A divalent organic group.

As the R ^1, R ^2, for example, is preferably used those having an alkylene group of the aromatic residues and n = 2 to 10 represented by the following formula group.

In the present invention, 2,2-bis [4- (2,3-dicarboxyphenoxy) phenyl] propane dianhydride mainly having a structural unit represented by the following formula from the viewpoint of amorphousness, melt moldability, and cost. A condensate of the product with m-phenylenediamine is preferably used. This polyetherimide is commercially available from Servic Innovative Plastics under the trademark “Ultem”.

The molecular weight of the amorphous PEI polymer used in the present invention is not particularly limited, but considering the mechanical properties, dimensional stability, and process passability of the resulting fiber, it is 390 ° C. and shear rate 1200 sec ⁻¹ . From the viewpoint, it is desirable that the weight average molecular weight (Mw) is 1000 to 80000. The use of a polymer having a high molecular weight is preferable because it is excellent in terms of fiber strength, heat resistance and the like, but it is more preferable that Mw is 10,000 to 50,000 from the viewpoint of resin production cost, fiberization cost, and the like.

  In particular, the amorphous PEI polymer used in the present invention needs to have a molecular weight distribution that is a ratio of the weight average molecular weight (Mw) to the number average molecular weight (Mn) of less than 2.5. When the molecular weight distribution is larger than this, not only the workability and stability in the fiber production process are deteriorated, but also the heat resistance of the fiber obtained from this polymer is inferior.

  On the other hand, when the molecular weight distribution is 1, it is an ideal monodisperse polymer. From this viewpoint, the lower limit of the molecular weight distribution of the amorphous PEI polymer is preferably 1.0.

  For example, the molecular weight distribution of the amorphous PEI polymer is preferably 1.0 to 2.4, and more preferably 1.0 to 2.3. Such an amorphous PEI polymer having a narrow molecular weight distribution can be obtained by, for example, the method exemplified in Japanese Patent Publication No. 2007-503513, but is not limited thereto.

  Although details will be described later in the Examples section, the weight average molecular weight (Mw), the number average molecular weight (Mn), and the molecular weight distribution mentioned here are, for example, gel permeation, which is a kind of size exclusion chromatography (SEC). It can be calculated in terms of polystyrene by an association chromatography (GPC).

  The amorphous PEI polymer may contain an antioxidant, a radical inhibitor, a matting agent, an ultraviolet absorber, a flame retardant, an inorganic substance, and other polymers as long as the effects of the present invention are not impaired. . Specific examples of such inorganic substances include carbon nanotubes, fullerenes, carbon black, graphite and other carbides; silicic acids such as talc, wollastonite, zeolite, sericite, mica, kaolin, clay, pyrophyllite, silica, bentonite, and alumina silicate. Metal oxides such as silicon oxide, magnesium oxide, alumina, zirconium oxide, titanium oxide and iron oxide; carbonates such as calcium carbonate, magnesium carbonate and dolomite; sulfates such as calcium sulfate and barium sulfate; calcium hydroxide, Hydroxides such as magnesium hydroxide and aluminum hydroxide; glass beads, glass flakes, glass powder, ceramic beads, boron nitride, silicon carbide and the like are used.

  Specific examples of other polymers include polyamide, polybutylene terephthalate, polyethylene terephthalate, modified polyphenylene ether, polysulfone, polyethersulfone, polyallylsulfone, polyketone, polyarylate, liquid crystal polymer, polyetherketone resin, polythioether. Ketone, polyetheretherketone, polyimide, polyamideimide, tetrafluoropolyethylene, polycarbonate and the like are used.

(Method for producing amorphous PEI fiber)
In the production of the amorphous PEI fiber used in the present invention, a known melt spinning apparatus can be used. That is, it can be obtained by melting and kneading amorphous PEI polymer pellets with a melt extruder, introducing the molten polymer into a spinning cylinder, measuring it with a gear pump, and winding the yarn discharged from the spinning nozzle. When the amorphous polymer is stretched, the shrinkage at high temperature increases. Therefore, the amorphous PEI fiber of the present invention winds the yarn discharged from the spinning nozzle as it is without stretching, It is preferable to use it as a yarn. The take-up speed at that time is not particularly limited, but it is not preferred if molecular orientation occurs on the spinning line, and it is preferably taken in the range of 500 m / min to 4000 m / min. If it is less than 500 m / min, it is not preferable from the viewpoint of productivity. On the other hand, if it exceeds 4000 m / min, not only the molecular orientation is sufficient to cause shrinkage at high temperatures, but also fiber breakage tends to occur. There are prisoners.
Further, the amorphous PEI fiber is not particularly limited with respect to the cross-sectional shape of the fiber at that time, and may be circular, hollow, or an atypical cross section such as a star shape.

(Physical properties of amorphous PEI fiber)
The amorphous PEI fibers obtained as described above may have, for example, a dry heat shrinkage of 5.0% or less at 200 ° C., specifically, all the temperatures from 100 to 200 ° C. In the temperature range, the dry heat shrinkage is preferably -1.0 to 5.0%. If the dry heat shrinkage rate exceeds 5.0%, the dimensional change of the product at the time of processing or use may increase. On the other hand, the same reason exists even if it is less than -1.0%. More preferably, the dry heat shrinkage is -1.0 to 4.5%, and more preferably 0 to 4.0%. The dry heat shrinkage referred to here is a value measured by the method described later.

  The amorphous PEI fiber obtained as described above preferably has a fiber strength at room temperature of 2.0 cN / dtex or more. When the fiber strength is less than 2.0 cN / dtex, it is not preferable because the process passability in making a fabric such as paper, non-woven fabric or woven fabric is deteriorated or the usage is limited. More preferably, it is 2.3 to 4.0 cN / dtex, and further preferably 2.5 to 4.0 cN / dtex.

  Further, the fineness of the amorphous PEI fiber of the present invention is not particularly limited as long as it can be subjected to a papermaking process. For example, the single fiber fineness may be about 0.1 to 5.0 dtex, It may be 3.0 dtex or less, more preferably 2.6 dtex or less (for example, 0.1 to 2.3 dtex). Amorphous PEI fibers with such single fiber fineness reduce the porosity of the paper-made flame retardant paper, flame retardant paper with heat resistance, flame retardant, low smoke generation, electrical insulation, etc. Can be advantageously used.

  Further, the fiber length is preferably about 0.5 to 12 mm, more preferably about 1.0 to 6.0 mm. If the fiber length is too short, there are some captives that the mechanical properties of the paper are not sufficient. On the other hand, if the fiber length is too long, the fiber opening property, dispersibility, etc. deteriorate, and the uniformity as paper is impaired. There are prisoners.

(Heat resistant fiber)
The heat-resistant fiber used in the present invention is an organic or inorganic heat-resistant fiber having a melting point or a thermal decomposition temperature of 200 ° C. or higher, and has flame retardancy and heat resistance in combination with amorphous PEI fiber. It is not particularly limited as long as it can be imparted, and various organic fibers and inorganic fibers can be used. These heat resistant fibers may be used alone or in combination of two or more.

  For example, examples of inorganic fibers include glass fibers, carbon fibers, silicon carbide fibers, alumina fibers, ceramic fibers, and various metal fibers (for example, gold, silver, copper, iron, nickel, titanium, stainless steel, etc.). .

  Examples of organic fibers include fully aromatic polyester fibers, polyphenylene sulfide fibers, para-aramid fibers, polysulfonamide fibers, phenol resin fibers, polyimide fibers, fibers made of heat-resistant polymers such as fluorine fibers, and the like. be able to.

  Among these heat-resistant fibers, from the viewpoint of physical properties of the obtained paper, wholly aromatic polyester fibers, glass fibers, polyphenylene sulfide fibers, para-aramid fibers, polysulfonamide fibers, and the like are preferable, and the water balance can be reduced. From the viewpoint, a wholly aromatic polyester fiber and glass fiber are more preferable, and from the viewpoint of improving flame retardancy, a wholly aromatic polyester fiber is particularly preferable.

The wholly aromatic polyester-based polymer is obtained by polymerization from aromatic diol, aromatic dicarboxylic acid, aromatic hydroxycarboxylic acid, etc. Among them, melt anisotropy (liquid crystallinity) showing optical anisotropy at the time of melting. For example, by placing the sample on a hot stage and heating in a nitrogen atmosphere and observing the transmitted light of the sample.
For example, such a melt anisotropic polyester fiber is marketed as “Vectran (registered trademark)” by Kuraray Co., Ltd.

(Physical properties of heat-resistant fiber)
The heat resistant fiber used in the present invention needs to have a melting point or a thermal decomposition temperature of 200 ° C. or higher. The melting point herein is a main endothermic peak temperature measured and observed with a differential scanning calorimeter (DSC) in accordance with “JIS K7121 test method”. In addition, the thermal decomposition temperature means that when heat is applied to the heat-resistant fiber, a part of the heat-resistant fiber disappears by decomposition, evaporation or sublimation, and the weight of the resin is reduced by 5.0%. Refers to temperature.

  Depending on the type of heat-resistant fiber, its physical properties vary, but from the viewpoint of improving the strength of flame retardant paper, the strength of the heat-resistant fiber may be, for example, 3 cN / dtex or more, preferably 5 cN / dtex or more, more preferably 7 cN / dtex or more. The elastic modulus of the heat resistant fiber is preferably, for example, 50 cN / dtex or more, and more preferably 100 cN / dtex or more.

  In addition, the fineness of the heat-resistant fiber used in the present invention is not particularly limited as long as it can be subjected to a papermaking process. For example, the single fiber fineness may be about 0.1 to 5.0 dtex, preferably May be 3.0 dtex or less, more preferably 2.6 dtex or less (0.1 to 2.3 dtex).

  Further, the fiber length of the heat resistant fiber is preferably about 0.5 to 12 mm, more preferably about 1.0 to 6.0 mm. If the fiber length is too short, there are some captives that the mechanical properties of the paper are not sufficient. On the other hand, if the fiber length is too long, the fiber opening property, dispersibility, etc. deteriorate, and the uniformity as paper is impaired. There are prisoners.

(Method for producing heat-resistant flame-retardant paper)
The heat-resistant flame retardant paper of the present invention can usually be suitably produced by a wet papermaking method. In the wet papermaking method, an aqueous slurry containing the amorphous PEI fibers and wholly aromatic polyester fibers may be prepared, and then the slurry may be subjected to a normal papermaking process. The aqueous slurry may contain a binder (for example, a water-soluble polymer fiber such as polyvinyl alcohol fiber, a heat-adhesive polymer fiber such as polyethylene terephthalate fiber (PET fiber)), and the like. In addition, you may perform a beating process with respect to the fiber used as needed.
Moreover, you may add a hot press process after a wet papermaking process in order to improve the uniformity and press-fit property of paper.

Unless the effects of the present invention are impaired, the heat-resistant flame retardant paper of the present invention may contain other fibers , paper strength improvers, fixing agents, antifoaming agents, dyes, ultraviolet absorbers, flame retardants, etc., depending on the purpose. Various fillers such as various additives, talc, karin, calcium carbonate, titanium dioxide and the like may be included. These raw materials are often added to the aqueous slurry, but may be appropriately attached by coating or the like.

  For example, as other fibers that can be used in combination, in addition to general-purpose fibers such as polyolefin fibers, polyester fibers, polyamide fibers, cellulose fibers, polysulfone fibers, aromatic para-aramid, polyaryl ketone fibers, poly Other heat resistant fibers such as sulfone fibers can be mentioned.

In the heat-resistant flame retardant paper of the present invention, it can be appropriately selected according to the type of heat-resistant fiber. For example, the ratio (weight) of the amorphous PEI fiber (A) and the heat-resistant fiber (B) Ratio) may be included in a ratio (weight ratio) of (A) / (B) = 30/70 to 98/2, preferably 35/65 to 90/10, more preferably 40/60 to 85. / 15.
If the ratio of amorphous PEI fibers is too small, there are some captives that cannot impart sufficient flame resistance, while if the proportion of heat-resistant fibers is too small, there are prisoners that cannot impart sufficient heat resistance.

  Further, the ratio of the total amount of amorphous PEI fibers and heat resistant fibers in the heat resistant flame retardant paper of the present invention may be, for example, 50 to 100 parts by weight from the viewpoint of flame retardancy and heat resistance. May be 55 to 98 parts by weight, more preferably 60 to 95 parts by weight.

  When the binder is included, the ratio of the binder to the total amount of 100 parts by weight of the amorphous PEI fiber and the heat-resistant fiber may be 3 to 100 parts by weight, preferably 5 to 80 parts by weight. Also good.

(Heat resistant flame retardant paper)
The heat-resistant flame retardant paper of the present invention thus obtained not only has excellent heat resistance and flame retardancy, but also has a low equilibrium moisture content and can be suitably used for various applications such as electrical and electronic parts. is there.

  For example, the heat-resistant flame retardant paper of the present invention has a low water content, and its equilibrium moisture content is, for example, 3.0% or less (for example, 0.01 to 2.8%), preferably 2.0% or less. Preferably it may be 1.0% or less. In addition, the equilibrium moisture content here is a value measured by the method described in the Example mentioned later.

  The heat-resistant flame retardant paper of the present invention is excellent in flame retardancy. For example, the carbonization length according to “JIS L1091 A-4 method” is, for example, 15.0 cm or less (for example, 1.0 cm to 15.0 cm). It may be 10.0 cm or less, more preferably 7.0 cm or less. In addition, the carbonization length here is a value measured by the method described in the Example (Example 1) mentioned later.

  The heat-resistant flame retardant paper of the present invention has a dry heat shrinkage at 200 ° C. of, for example, 4.0% or less. Specifically, in all temperature ranges from 100 to 200 ° C., the dry heat shrinkage is − It is preferable that it is 1.0 to 3.5%. More preferably, the dry heat shrinkage at 200 ° C. may be −1.0 to 3.0%, more preferably 0 to 2.5%. The dry heat shrinkage referred to here is a value measured by the method described in Examples described later.

  The thickness of the heat-resistant flame retardant paper of the present invention can be appropriately set according to its use and is not particularly limited. For example, the thickness can be selected from a wide range of about 0.01 to 1 mm. However, the thickness at which the heat-resistant flame retardant paper of the present invention can exhibit excellent heat resistance and flame resistance may be, for example, 0.1 mm or less.

Further, the heat resistant flame retardant basis weight of the present invention may be, for example, about 10 to 150 g / m ² depending on the ratio of the fiber, and more preferably 100 g / m ² or less from the viewpoint of weight reduction. It may be.

2. Effect of Electrolytic Capacitor 100 According to the Embodiment The electrolytic capacitor 100 according to the embodiment configured as described above is more excellent in flame retardancy than the conventional one, as can be seen from an example (Example 2) described later. It becomes an electrolytic capacitor.

  In addition, as can be seen from an example (Example 2) to be described later, the electrolytic capacitor 100 according to the embodiment is a fiber that constitutes a heat-resistant flame retardant paper even if the content of water and boric acid in the electrolytic solution is increased. Since it is difficult for the unraveling to occur, the separator easily breaks and the durability against pressure at the time of abnormal voltage application is reduced, and the long-term reliability of the electrolytic capacitor is reduced. It becomes possible to increase the flame retardancy.

  Moreover, since the electrolytic capacitor 100 according to the embodiment includes 30% by weight of amorphous polyetherimide fiber, the electrolytic capacitor 100 has a predetermined flame retardancy improving effect.

  In addition, the electrolytic capacitor 100 according to the embodiment has the necessary performance as an electrolytic capacitor while having a good balance of flame retardancy and long-term reliability because the electrolytic solution contains 10 wt% water and 20 wt% boric acid. The electrolytic capacitor having

Moreover, since the density of the separator is 0.72 g / cm ³ in the electrolytic capacitor 100 according to the embodiment, the separator performance and tan δ (loss angle tangent) characteristics such as heat resistance, insulation, and withstand voltage characteristics, The electrolytic capacitor has the performance of an electrolytic capacitor such as ESR (equivalent series resistance) characteristics and life.

  In addition, the electrolytic capacitor 100 according to the embodiment is such that the amorphous polyetherimide fiber is formed from an amorphous polyetherimide polymer having a molecular weight distribution (Mw / Mn) of less than 2.5. In addition to being excellent in flame retardancy, an electrolytic capacitor having a heat-resistant fiber with low smoke generation, flexibility, and small shrinkage at high temperatures is obtained.

  Moreover, since the heat resistant flame retardant paper includes at least a heat resistant fiber other than the amorphous polyetherimide fiber in addition to the amorphous polyetherimide fiber, the electrolytic capacitor 100 according to the embodiment has “difficulty”. It becomes an electrolytic capacitor capable of improving the “flammability”, “formability in the paper making process”, and “characteristics of the fiber included in the heat-resistant flame-retardant paper” with good balance.

  In the electrolytic capacitor 100 according to the embodiment, since the heat-resistant fiber is a PAR fiber having a melting point or a thermal decomposition temperature of 200 ° C. or higher, the heat resistance of the entire heat-resistant flame retardant paper can be ensured. It becomes an electrolytic capacitor.

  Moreover, since the weight ratio of the amorphous polyetherimide fiber to the heat-resistant fiber is 30/45, the electrolytic capacitor 100 according to the embodiment has “flame resistance”, “formability in papermaking process”, and “ It becomes an electrolytic capacitor capable of improving in a well-balanced manner the “dissolving property of fibers contained in the heat-resistant flame-retardant paper”.

  In the electrolytic capacitor 100 according to the embodiment, the ratio of the total weight of the amorphous polyetherimide fiber and the heat resistant fiber to the total weight of the heat resistant flame retardant paper is 50% or more. Thus, an electrolytic capacitor capable of improving the “flame resistance”, “formability in the paper making process” and “difficulty property of fibers contained in the heat resistant flame retardant paper” in a well-balanced manner is obtained.

  In addition, the electrolytic capacitor 100 according to the embodiment ensures a predetermined flame retardance because the carbonization length of the heat-resistant flame-retardant paper is 15.0 cm or less when measured using the “JIS L1091 A-4 method”. It becomes an electrolytic capacitor that can.

  In addition, the electrolytic capacitor 100 according to the embodiment is an electrolytic capacitor with high long-term reliability because the heat-resistant flame retardant paper has a dry heat shrinkage rate at 200 ° C. of 4.0% or less.

  In addition, the electrolytic capacitor 100 according to the embodiment has an equilibrium moisture content of 3.0% or less of the heat-resistant flame retardant paper, so that the amount of water contained in the electrolytic solution can be precisely controlled and Become.

  In addition, the electrolytic capacitor 100 according to the embodiment is included in “flame retardant”, “formability in paper making process”, and “heat resistant flame retardant paper” because the heat resistant fiber is composed of wholly aromatic polyester fiber. An electrolytic capacitor capable of improving the “dissolvability characteristic of the fiber” in a well-balanced manner.

  EXAMPLES Hereinafter, although an Example demonstrates this invention in detail, this invention is not limited at all by this Example.

[Example 1]
Example 1 is an example for showing that the heat-resistant flame retardant paper used for the electrolytic capacitor of the present invention has excellent flame retardancy, a low heat shrinkage rate and a low equilibrium moisture content. In Example 1, Test Examples 1 to 15 are examples of the present invention, and Test Examples 16 and 17 are comparative examples of the present invention.

1. Evaluation Method In each test example, the physical properties of the polymer and paper were measured by the following methods.

[Molecular weight distribution Mw / Mn]
The molecular weight distribution of the sample was measured using water permeation gel permeation chromatography (GPC) and 1500 ALC / GPC (polystyrene conversion). The sample was dissolved so as to be 0.2% by weight using chloroform as a solvent, and then filtered for measurement. The molecular weight distribution (Mw / Mn) was determined from the ratio of the obtained weight average molecular weight (Mw) and number average molecular weight (Mn).

[Fiber strength cN / dtex]
In accordance with “JIS L1013 test method”, a pre-humidified yarn is measured under the conditions of a test length of 20 cm, an initial load of 0.25 cN / dtex and a tensile speed of 50% / min, and an average value of n = 20 is adopted. did. The fiber fineness (dtex) was determined by a mass method.

[Carbonization length cm]
Carried out in accordance with “JIS L1091 A-4 test method”, the carbonization length when heated for 3 seconds with a Bunsen burner 17 mm away from the lower end of the sample was measured with respect to the lower end of the sample arranged vertically, n = An average value of 5 was adopted.

[Dry heat shrinkage%]
Fiber length or fabric length (Xcm) after holding a fiber cut out to 10 cm or a paper made of the fiber cut into a 10 cm square for 10 minutes in an air thermostat kept at 200 ° C. without fixing the end. From this, it was calculated using the following formula.
Dry heat shrinkage (%) = <X / 10> × 100

[Equilibrium moisture percentage]
Consistent with “JIS L1013”, the sample was completely dried in an atmosphere of 120 ° C., then adjusted at a temperature of 20 ° C. and a relative humidity of 65% RH for 72 hours, and included in the sample with respect to the weight of the sample in the absolutely dry state. The moisture content was calculated and expressed as a percentage (%).

[Comprehensive evaluation]
When all of “carbonization length 15.0 cm or less”, “dry heat shrinkage 4.0% or less” and “equilibrium moisture ratio 3.0% or less” were satisfied, the overall evaluation was “◯”. If the carbonization length is 15.0 cm or less, the dry heat shrinkage is 4.0% or less, and the equilibrium moisture content is 3.0% or less, the overall evaluation is “x”. .

2. Sample Preparation In each test example, the heat-resistant flame retardant paper was prepared by the following method.

(Reference example: Preparation of amorphous PEI fiber)
(1) An amorphous PEI polymer (“ULTEM 9001” manufactured by Servic Innovative Plastics) having a weight average molecular weight (Mw) of 32000, a number average molecular weight (Mn) of 14500, and a molecular weight distribution of 2.2 is 150 ° C. Vacuum dried for 12 hours.

(2) The polymer of the above (1) was discharged from a round hole nozzle under the conditions of a spinning head temperature of 390 ° C., a spinning speed of 2000 m / min, and a discharge rate of 50 g / min, and a 220 dtex / 100 f multifilament (single fiber fineness; 2 dtex, strength: 2.6 cN / dtex, dry heat shrinkage at 200 ° C .; 3.5%). The obtained filament was cut into a fiber length of 10 mm to obtain short fibers of amorphous PEI fibers.

(Test Example 1)
30 parts by weight of amorphous PEI fiber obtained in Reference Example and wholly aromatic polyester fiber (manufactured by Kuraray Co., Ltd., “Vectran”, single fiber fineness: 2.8 dtex, fiber length: 5 mm, melting point 370 ° C.) 45 Using a weight part and 25 parts by weight of a binder fiber (“EP101: polyester binder fiber” manufactured by Kuraray Co., Ltd., single fiber fineness: 1.5 dtex, fiber length: 5 mm), wet papermaking is performed, and the basis weight is 80 g / m ^2. Made paper. The physical properties of the obtained paper are shown in FIG.

(Test Examples 2 to 6)
Except that the ratio of the amorphous PEI fiber, wholly aromatic polyester fiber, and binder fiber used in Test Example 1 is the ratio shown in FIG. A 40 g / m ² paper was prepared. The physical properties of the obtained paper are shown in FIG.

(Test Example 7)
40 parts by weight of amorphous PEI fiber used in Test Example 1, 30 parts by weight of wholly aromatic polyester fiber, binder fiber (“VP105; polyvinyl alcohol binder fiber” manufactured by Kuraray Co., Ltd., single fiber fineness; Wet paper was made using 30 parts by weight of 5 dtex and fiber length of 3 mm to prepare a paper having a basis weight of 40 g / m ² . The physical properties of the obtained paper are shown in FIG.

(Test Example 8)
90 parts by weight of amorphous PEI fibers used in Test Example 1, 3 parts by weight of wholly aromatic polyester fibers, binder fibers (“VP105; polyvinyl alcohol binder fibers” manufactured by Kuraray Co., Ltd., single fiber fineness; Wet paper was made using 7 parts by weight of 5 dtex and fiber length of 3 mm to prepare a paper having a basis weight of 40 g / m ² . The physical properties of the obtained paper are shown in FIG.

(Test Example 9)
Tested except that polyphenylene sulfide fiber (“Procon” manufactured by Toray Industries, Inc., single fiber fineness: 4.0 dtex, fiber length: 6 mm, melting point 285 ° C.) was used in place of the wholly aromatic polyester fiber used in Test Example 1. Wet paper was made in the same manner as in Example 3 to prepare a paper having a basis weight of 40 g / m ² . The physical properties of the obtained paper are shown in FIG.

(Test Example 10)
Instead of the wholly aromatic polyester fiber used in Test Example 1, glass fiber (“ECS03-350” manufactured by Central Glass Co., Ltd., single fiber fineness: 2.0 dtex, fiber length: 3 mm, no melting point) is used. Wet paper was made in the same manner as in Test Example 3 to prepare a paper with a basis weight of 40 g / m ² . The physical properties of the obtained paper are shown in FIG.

(Test Example 11)
Instead of using the para-aramid fiber (“Kevlar 49” manufactured by Toray Industries, Inc., single fiber fineness: 1.7 dtex, fiber length: 6 mm, decomposition temperature 490 ° C.) instead of the wholly aromatic polyester fiber used in Test Example 1, Wet paper was made in the same manner as in Test Example 3 to prepare a paper with a basis weight of 40 g / m ² . The physical properties of the obtained paper are shown in FIG.

(Test Example 12)
60 parts by weight of amorphous PEI fibers used in Test Example 1 and 40 parts by weight of para-aramid fibers (“Kevlar 49” manufactured by Toray Industries, Inc., single fiber fineness: 1.7 dtex, fiber length: 6 mm, decomposition temperature 490 ° C.) Was used to make paper with a basis weight of 40 g / m ² . The physical properties of the obtained paper are shown in FIG.

(Test Example 13)
80 parts by weight of amorphous PEI fiber used in Test Example 1 and cellulose fiber (“Wait for wet nonwoven fabric” manufactured by Daiwabo Rayon Co., Ltd., single fiber fineness: 1.3 dtex, fiber length: 3 mm, decomposition temperature 310 ° C.) Using 20 parts by weight, wet papermaking was performed to prepare a paper with a basis weight of 40 g / m ² . The physical properties of the obtained paper are shown in FIG.

(Test Example 14)
40 parts by weight of amorphous PEI fiber used in Test Example 1 and 20 parts by weight of polysulfonamide fiber (“TANLON” manufactured by Shanghai TNLON, single fiber fineness: 1.2 dtex, fiber length: 3 mm, decomposition temperature 490 ° C.) And 30 parts by weight of binder fiber (“VP105; polyvinyl alcohol-based binder fiber” manufactured by Kuraray Co., Ltd., single fiber fineness: 1.5 dtex, fiber length: 3 mm), and paper having a basis weight of 40 g / m ² . It was created. The physical properties of the obtained paper are shown in FIG.

(Test Example 15)
Using 50 parts by weight of the amorphous PEI fiber used in Test Example 1 and 50 parts by weight of the binder fiber used in Test Example 1, wet papermaking was performed to prepare a paper with a basis weight of 40 g / m ² . The physical properties of the obtained paper are shown in FIG.

(Test Example 16)
The physical properties of a commercially available meta-aramid heat resistant paper (“Nomex paper” manufactured by DuPont) were measured in the same manner as in the test example, and the physical properties are shown in FIG.

(Test Example 17)
Wet paper is made using commercially available cellulose fibers (“Daiwabo Rayon Co., Ltd.“ Wet cotton for wet nonwoven fabric ”, single fiber fineness: 1.3 dtex, fiber length: 3 mm, decomposition temperature 310 ° C.), and cellulose having a basis weight of 40 g / m ² . Made paper. The physical properties of the obtained paper are shown in FIG.

FIG. 2 is a diagram showing the evaluation results of each test example in Example 1.
As is clear from FIG. 2, the heat-resistant flame retardant paper obtained in Test Examples 1 to 15 (Examples of the present invention) contains a specific amorphous PEI fiber or a specific amorphous property. Since it is composed of PEI fibers and heat-resistant fibers, it has a short carbonization length, a low shrinkage rate at 200 ° C., and a low equilibrium water content of paper.

  Various heat-resistant fibers have been shown to be able to impart flame resistance to heat-resistant flame-retardant paper by combining with amorphous PEI fibers, but especially melt anisotropic fully aromatic polyester fibers and glass fibers are flame retardant. It was preferred because of its heat resistance and low moisture content.

  Further, the ratio of the total amount of amorphous PEI fibers and heat resistant fibers to the entire heat resistant flame retardant paper (parameter E) is 70 parts by weight or more, and the flame retardancy is good, particularly 70 to 90 parts by weight. It showed high flame retardancy. Moreover, the shrinkage rate at 200 ° C. tended to decrease as the ratio of heat resistant fiber to amorphous PEI fiber increased.

  Moreover, in the meta-aramid heat-resistant paper currently marketed (Test Example 16), although it has flame retardancy, the equilibrium moisture content was not suppressed. In addition, the cellulose paper (Test Example 17) made using commercially available cellulose fibers was not flame retardant and not only burned but also its equilibrium moisture content remained high.

[Example 2]
Example 2 is an example for showing that the electrolytic capacitor of the present invention has excellent “flame retardancy” and excellent “fiber unbreakability characteristics”. In Example 2, Test Examples 21 to 26 are examples of the present invention, and Test Examples 18 to 20 and 27 to 30 are comparative examples of the present invention.

1. Evaluation Method In each test example, “flame retardancy” and “fiber unraveling property” were measured by the following methods.

[Flame retardance]
The evaluation of “flame retardant” was made by fixing a capacitor element impregnated with an electrolytic solution vertically with the lead out facing up, and then indirectly burning a blue gas burner flame at the lower end of the capacitor element for 10 seconds. This was done by burning the element, then separating the flame from the capacitor element and measuring the burning duration of the capacitor element. As an evaluation standard, an evaluation of “◎” is given when the combustion immediately stops when the flame is separated from the capacitor element, and when the combustion stops within 10 seconds after the flame is separated from the capacitor element. An evaluation of “◯” is given, and when combustion stops in 10 to 30 seconds after separating the flame from the capacitor element, an evaluation of “△” is given, and 30 seconds have elapsed after the flame is separated from the capacitor element. Even when combustion did not stop, an evaluation of “x” was given.

[Characteristics of difficulty in unraveling fibers]
The “fiber unbreakability characteristic” is defined as the fiber breakage at the cut surface of the heat resistant flame retardant paper or cellulose paper after immersing the heat resistant flame retardant paper or cellulose paper having a cut surface in an electrolyte at 105 ° C. for 24 hours. This was carried out by visually observing with a 20 × stereomicroscope. As an evaluation standard, when it is determined that the fiber unraveling has not increased in the cut surface, an evaluation of `` ○ '' is given, and when it is determined that the fiber unraveling has slightly increased in the cutting surface, an evaluation of `` △ '' is given, An evaluation of “x” was given when it was judged that the fiber unraveling increased in the cut surface.

[Comprehensive evaluation]
When both “Flame Retardancy” and “Fiber Difficulty Properties” were both given “◯” or higher, the overall evaluation was “◯”. When an evaluation of “Δ” was given for either “flame retardant” or “fiber unraveling property”, the overall evaluation was “Δ”. When an evaluation of “x” was given for either “flame retardant” or “fiber unraveling property”, the overall evaluation was “x”.

2. Preparation of sample (Test Examples 18 to 20)
An electrolytic capacitor having the same configuration as the electrolytic capacitor according to the embodiment was produced, and this was used as an electrolytic capacitor according to Test Examples 18-20. However, the cellulose paper of Test Example 17 was used as the separator. Further, as shown in FIG. 3, in the case of Test Example 18, an electrolytic solution containing 10% by weight of water and 10% by weight of boric acid was used as the electrolytic solution. An electrolytic solution containing 15% by weight and containing 10% by weight of boric acid was used. In the case of Test Example 20, an electrolytic solution containing 10% by weight of water and 20% by weight of boric acid was used.

(Test Examples 21 to 23)
An electrolytic capacitor having the same configuration as the electrolytic capacitor according to the embodiment was produced, and this was used as the electrolytic capacitor according to Test Examples 21-23. However, as shown in FIG. 3, in the case of Test Example 21, an electrolytic solution containing 10% by weight of water and 10% by weight of boric acid was used as the electrolytic solution, and in the case of Test Example 22, water was used. An electrolytic solution containing 15% by weight and containing 10% by weight of boric acid was used. In the case of Test Example 23, an electrolytic solution containing 10% by weight of water and 20% by weight of boric acid was used.

(Test Examples 24-26)
An electrolytic capacitor having the same configuration as the electrolytic capacitor according to the embodiment was produced, and this was used as an electrolytic capacitor according to Test Examples 24-26. However, as shown in FIG. 3, an electrolytic solution containing 5% by weight of water is used in the case of Test Example 24, and an electrolytic solution containing 5% by weight of boric acid is used in the case of Test Example 25 as shown in FIG. In the case of Test Example 26, an electrolytic solution containing 35% by weight of boric acid was used.

(Test Examples 27 to 30)
An electrolytic capacitor having the same configuration as the electrolytic capacitor according to the embodiment was produced, and this was used as the electrolytic capacitor according to Test Examples 27-30. However, as shown in FIG. 3, in the case of Test Example 27, an electrolyte solution containing no water was used, and in the case of Test Example 28, an electrolyte solution containing 20% by weight of water was used as the electrolyte solution. In the case of Example 29, an electrolytic solution containing no boric acid was used, and in the case of Test Example 30, an electrolytic solution containing 40% by weight of boric acid was used.

3. Evaluation Results FIG. 3 is a diagram showing the evaluation results of the respective test examples in Example 2.
From Test Examples 18 to 20, the following was found. That is, even when cellulose paper is used for the separator, when an electrolytic solution containing 10% by weight of water and 10% by weight of boric acid is used as the electrolytic solution, an excellent “flame retardant (◯)” (Test Example 18), and when the content of water is 15% by weight (Test Example 19) or when the content of boric acid is slightly increased to 20% by weight (Test Example 20), Test Example 18 “Flame retardance (◎)” superior to that in the above case was obtained. On the other hand, in any of the electrolytic capacitors (Test Examples 18 to 20), it was not possible to obtain an excellent “fiber undissolved property”.

  Moreover, the following was found from Test Examples 21 to 23. That is, when a heat-resistant flame retardant paper containing amorphous PEI fibers is used for the separator, excellent “flame resistance (◎)” and excellent “hard fiber breakage” in any electrolytic capacitor. Satisfaction ”was obtained.

  Moreover, the following was found from Test Examples 24 and 22. That is, when the heat-resistant flame retardant paper containing amorphous PEI fibers is used for the separator, the water content is high even when the water content is 5% by weight (Test Example 24). Even in the case of% by weight (Test Example 22), an excellent “characteristic of difficulty in unraveling fibers” was obtained. In addition, the following was found from Test Examples 25 and 26. That is, when the heat-resistant flame retardant paper containing amorphous PEI fibers is used for the separator, the boric acid content is high even when the boric acid content is 5% by weight (Test Example 25). Also in the case of% by weight (Test Example 26), excellent “fiber unraveling characteristics” were exhibited.

  Moreover, the following was found from Test Examples 27-30. That is, even when heat-resistant flame retardant paper containing amorphous PEI fibers is used for the separator, when the water content is reduced to 0% by weight (Test Example 27), “ When the “flammability” cannot be obtained and the water content is increased to 20% by weight (Test Example 28), the aluminum foil constituting the anode foil and the cathode foil is likely to deteriorate, or the structure on the anode side In some cases, the corrosion resistance of the member may decrease. Further, when the content of boric acid is reduced to 0% by weight (Test Example 29), excellent “flame resistance” cannot be obtained, and when the content of boric acid is increased to 40% by weight (Test Example) In 30), it is difficult to sufficiently impregnate the capacitor element with the electrolytic solution due to the viscosity of the electrolytic solution being too high, which may cause a decrease in performance of the electrolytic capacitor.

  In summary, a heat-resistant flame retardant paper containing amorphous PEI fibers is used for the separator, and 5 to 15% by weight of water and 5 to 35% by weight of boric acid are used as the electrolyte. It has been clarified that an excellent “flame retardance” and an excellent “fiber unbreakability characteristic” can be obtained when an electrolyte solution containing is used.

[Example 3]
Example 3 is an example for showing that the electrolytic capacitor of the present invention has high “tensile strength”. In Example 3, Test Examples 31 and 32 are examples of the present invention, and Test Example 33 is a comparative example of the present invention.

1. Evaluation Method In each test example, “tensile strength” was measured by the following method.

[Tensile strength]
Evaluation of “tensile strength” is to measure the tensile strength of a heat-resistant flame retardant paper or cellulose paper using a digital load meter (SV55 manufactured by Imada Seisakusho) after the heat-resistant flame retardant paper or cellulose paper is immersed in water. It was done by doing. In addition, immersion in water was 1 second, and liquid removal was performed immediately after immersion. In each test example, the measurement was performed once for five samples, and the average value was defined as “tensile strength”. Cellulose paper has different “tensile strength” in the vertical and horizontal directions, so the value obtained by arithmetically averaging “longitudinal tensile strength” and “lateral tensile strength” is used as “tensile strength”. did.

[Evaluation]
The evaluation was “◯” when the “tensile strength” exceeded the “tensile strength” of cellulose.

2. Sample preparation (Test Examples 31 to 33)
A heat resistant flame retardant paper having the same configuration as in Test Example 1 was cut into a size of 15 mm in width and 75 mm in length to obtain a sample of Test Example 31. Further, a heat-resistant flame retardant paper having the same configuration as in Test Example 7 was cut into a size of 15 mm in width and 75 mm in length to obtain a sample in Test Example 32. Further, a cellulose paper having the same configuration as in Test Example 17 was cut into a size of 15 mm in width and 75 mm in length to obtain a sample in Test Example 33.

3. Evaluation Results FIG. 4 is a diagram showing the evaluation results of each test example in Example 3.
As can be seen from Test Examples 31 to 33, both the heat-resistant flame-retardant paper containing amorphous PEI fibers (Test Examples 31 and 32) were immersed in water rather than the case of cellulose paper (Test Example 33). Later "tensile strength" was high.

  In summary, it has become clear that a high “tensile strength” can be obtained when a heat-resistant flame retardant paper containing amorphous PEI fibers is used for the separator.

  As mentioned above, although the electrolytic capacitor of this invention was demonstrated based on said each embodiment, this invention is not limited to said each embodiment, It implements in a various aspect in the range which does not deviate from the summary. Is possible.

DESCRIPTION OF SYMBOLS 100 ... Electrolytic capacitor, 110 ... Capacitor element, 120 ... Anode foil, 130 ... Cathode foil, 140 ... Separator, 150 ... Anode side external lead terminal, 160 ... Cathode side external lead terminal, 170 ... Elastic sealing body, 180 ... Metal case

Claims (12)

The anode foil, the cathode foil, and the separator are provided with an anode foil having an anodized film on the surface, a cathode foil, and a separator, with the separator interposed between the anode foil and the cathode foil. An electrolytic capacitor having a structure formed by immersing a capacitor element obtained by winding in an electrolytic solution,
The separator, Ri Do heat resistant flame燃紙containing at least amorphous polyetherimide fiber,
The heat-resistant flame retardant paper comprises 30% to 90% by weight of amorphous polyetherimide fiber . The anode foil, the cathode foil, and the separator are provided with an anode foil having an anodized film on the surface, a cathode foil, and a separator, with the separator interposed between the anode foil and the cathode foil. An electrolytic capacitor having a structure formed by immersing a capacitor element obtained by winding in an electrolytic solution,
The separator, Ri Do heat resistant flame燃紙containing at least amorphous polyetherimide fiber,
In addition to the amorphous polyetherimide fiber, the heat resistant flame retardant paper includes at least a heat resistant fiber other than the amorphous polyetherimide fiber,
The electrolytic capacitor according to claim 1, wherein a weight ratio of the amorphous polyetherimide fiber to the heat resistant fiber is 30/70 to 98/2. The electrolytic capacitor according to claim 2 ,
The heat resistant fiber has an melting point or a thermal decomposition temperature of 200 ° C. or higher. The electrolytic capacitor according to claim 2 or 3 ,
The electrolytic capacitor characterized in that the ratio of the total weight of the amorphous polyetherimide fiber and the heat-resistant fiber to the total weight of the heat-resistant flame-retardant paper is 50% or more. In the electrolytic capacitor in any one of Claims 2-4 ,
An electrolytic capacitor characterized in that the carbonization length of the heat-resistant flame-retardant paper is 15.0 cm or less as measured using "JIS L1091 A-4 method". In the electrolytic capacitor in any one of Claims 2-5 ,
The electrolytic capacitor, wherein the heat-resistant flame retardant paper has a dry heat shrinkage at 200 ° C. of 4.0% or less. In the electrolytic capacitor in any one of Claims 2-6 ,
An electrolytic capacitor, wherein the heat-resistant flame retardant paper has an equilibrium moisture content of 3.0% or less. In the electrolytic capacitor in any one of Claims 2-7 ,
The electrolytic capacitor is characterized in that the heat-resistant fiber is composed of at least one selected from the group consisting of wholly aromatic polyester fibers, glass fibers, and polysulfonamide fibers. In the electrolytic capacitor in any one of Claims 2-7 ,
The electrolytic capacitor is characterized in that the heat-resistant fiber is composed of a melt-anisotropic wholly aromatic polyester fiber. In the electrolytic capacitor in any one of Claims 1-9 ,
The electrolytic capacitor includes 5 to 15% by weight of water and 5 to 35% by weight of boric acid. In the electrolytic capacitor in any one of Claims 1-10 ,
Density of the ^separator, an electrolytic capacitor, characterized in that in the range of ^{0.25g / cm 3 ~0.95g / cm 3} . In the electrolytic capacitor in any one of Claims 1-11 ,
The electrolytic capacitor, wherein the amorphous polyetherimide fiber is formed from an amorphous polyetherimide polymer having a molecular weight distribution (Mw / Mn) of less than 2.5.

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