JP2008205192A - Tape for securing winding edge of aluminum electrolytic capacitor element and aluminum electrolytic capacitor - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide adhesive tape for securing the winding edge of an aluminum electrolytic capacitor by which capacitance is not decreased because of loose winding of a capacitor element even under an atmosphere of high temperature when it is used for the aluminum electrolytic capacitor and to provide the aluminum electrolytic capacitor using it. <P>SOLUTION: The tape for securing the winding edge of the aluminum electrolytic capacitor element is composed of a support base material and an adhesive layer. In this case, the adhesive layer contains an adhesive and lamellar silicate. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a tape for winding an aluminum electrolytic capacitor element composed of a support base and an adhesive layer, and an aluminum electrolytic capacitor using the tape.

  Conventionally, adhesives and pressure-sensitive adhesive tapes have been used for element winding of aluminum electrolytic capacitors, and pressure-sensitive adhesive tape systems that can be easily mechanized have become the mainstream. For this pressure-sensitive adhesive tape, rubber-based and acrylic pressure-sensitive adhesive tapes using polypropylene, polyphenylene sulfide, polymethylpentene film or the like as a supporting substrate have been used (Patent Documents 1 to 3).

  Here, the aluminum electrolytic capacitor described above is required to have heat resistance. For example, a wet aluminum electrolytic capacitor for guaranteeing a high temperature is required to have a heat resistance of 150 ° C.

  Further, in the case of chip components for surface mounting, heat resistance of 250 ° C. or higher capable of withstanding the temperature during solder reflow is required because of the increase in solder melting temperature due to recent lead removal. For this reason, also about the adhesive tape used as an adhesive tape for aluminum electrolytic capacitor element winding prevention, the heat resistance with respect to the load temperature concerning an aluminum electrolytic capacitor element is requested | required.

  Further, in the dry aluminum electrolytic capacitor, there is a heat treatment step of 250 ° C. or more in the carbonization treatment step of the electrolytic paper or the separator in the production process. Therefore, high heat resistance is also required in dry aluminum electrolytic capacitors.

  However, the above-described conventional adhesive tape for preventing winding of an aluminum electrolytic capacitor has a problem in that the capacitor element is loosened due to insufficient heat resistance, resulting in a decrease in capacitance.

JP-A-5-101986 JP 2001-93782 A Japanese Patent Laid-Open No. 5-101985

  Accordingly, in view of the above circumstances, the present invention provides an adhesive tape for winding an aluminum electrolytic capacitor that does not cause a decrease in capacitance due to loose winding of an aluminum electrolytic capacitor element even in a high-temperature atmosphere, and an aluminum electrolysis using the same The object is to provide a capacitor.

  As a result of intensive studies to achieve the above object, the present inventors have found that the above object can be achieved by using the following aluminum electrolytic capacitor element winding tape, and have completed the present invention. .

  That is, the present invention is an aluminum electrolytic capacitor element winding tape comprising a support base and an adhesive layer, wherein the adhesive layer contains an adhesive and a layered silicate.

  In the tape for winding an aluminum electrolytic capacitor element in the present invention, the pressure-sensitive adhesive layer preferably contains 1 to 40 parts by weight of the layered silicate with respect to 100 parts by weight of the pressure-sensitive adhesive.

  The tape for winding an aluminum electrolytic capacitor element in the present invention has a sticking surface of an adhesive layer attached to a stainless steel plate, a sticking area of 10 mm × 20 mm, a working temperature of 175 ° C., a load of 25 g, and a deviation distance after 1 hour ( The shear holding force is preferably 0.3 mm or less.

  The aluminum electrolytic capacitor in the present invention is characterized by using the aluminum electrolytic capacitor element winding tape.

  The aluminum electrolytic capacitor element winding tape of the present invention contains layered silicate in the pressure-sensitive adhesive layer, so that the adhesive force can be maintained on the adherend even in a high-temperature atmosphere, and the capacitor element can be wound. An aluminum electrolytic capacitor capable of preventing a decrease in capacitance due to loosening can be provided and is effective.

  The adhesive tape for winding an aluminum electrolytic capacitor of the present invention is composed of a support base material and an adhesive layer. This will be specifically described below.

  The support substrate used in the present invention is not particularly limited, but those having heat resistance are preferred. For example, a plastic film having a melting temperature of 175 ° C. or higher and subjected to a stretching treatment is more preferable. Specifically, a polyester film such as polyethylene terephthalate (PET), a polyphenylene sulfide (PPS) film, a polyetherimide (PEI) ) Film, polysulfone (PSF) film, polyether ether ketone (PEEK) film, polyarylate (PAR) film, aramid film, polyimide film and the like. Kraft paper, Manila hemp paper, synthetic fiber paper, or a mixed paper made of two or more of these can be used.

  The thickness of the support base material can be selected as appropriate as long as the workability of winding the capacitor element is not impaired, but is usually preferably 5 to 100 μm, more preferably about 9 to 50 μm.

  Further, the heat shrinkage rate in the tape width direction of the supporting substrate is preferably 5% or less, more preferably 3% or less, and still more preferably with respect to the load temperature (-30 to 300 ° C.) applied to the capacitor element. 1.5% or less. As an example, a biaxially stretched polyester film (for example, trade name: LCP film, manufactured by Sumitomo Chemical Co., Ltd.), a biaxially stretched polyphenylene sulfide film (for example, trade name: Torelina 3030, manufactured by Toray Industries, Inc.) and the like can be given. In the biaxially stretched polyester film, the thermal shrinkage in the tape width direction is 5% or less in the temperature range up to 150 ° C. In the biaxially stretched polyphenylene sulfide film, the thermal shrinkage in the tape width direction is 5% or less in the temperature range up to 240 ° C. The method for measuring the heat shrinkage rate is a solder reflow furnace (CPL-104S, manufactured by Noritake Co., Ltd.) in which the adhesive tape is cut into a 20 mm square in a tape form, bonded to a BA plate, and set to a predetermined peak temperature. And the size of the tape before and after the heating is measured in both the MD direction and the TD direction using a projector (manufactured by Mitutoyo: PROFILE PROJECTOR PJ-H300F). The BA plate refers to a SUS304 plate (BA5 finish SUS304 manufactured by Nippon Metal Co., Ltd.) surface-finished to BA5 according to JIS “BA finish”.

  The material and configuration of the pressure-sensitive adhesive layer of the pressure-sensitive adhesive tape of the present invention are not particularly limited as long as it has adhesiveness, but normally used pressure-sensitive adhesives such as acrylic pressure-sensitive adhesives, rubber-based pressure-sensitive adhesives, and silicones An adhesive such as a system adhesive can be used. Among these, it is preferable to use an acrylic adhesive.

  As the acrylic pressure-sensitive adhesive, an acrylic monomer having a low glass transition temperature (Tg) that gives adhesiveness and heat resistance can be used as a main monomer. Further, a high Tg comonomer that gives adhesiveness and cohesive force, a monoethylenically unsaturated monomer that is a functional group-containing monomer used to improve crosslinkability and adhesiveness, and the like can also be used.

  Examples of the main monomer include methyl (meth) acrylate, ethyl (meth) acrylate, butyl (meth) acrylate, isoamyl (meth) acrylate, n-hexyl (meth) acrylate 2-ethylhexyl (meth) acrylate, and isooctyl (meth) ) Acrylates, isononyl (meth) acrylates, decyl (meth) acrylates, and acrylic polymers using one or more alkyl (meth) acrylates such as dodecyl (meth) acrylate as monomer components. The acrylic pressure-sensitive adhesive has relatively high heat resistance and is the most suitable pressure-sensitive adhesive for the present invention.

  Examples of the comonomer include vinyl group-containing compounds such as vinyl acetate, vinyl propionate, vinyl ether, styrene, acrylonitrile, and methacrylonitrile.

  Examples of the functional group-containing monomer include carboxyl group-containing monomers such as acrylic acid, methacrylic acid, itaconic acid, maleic acid, fumaric acid, and crotonic acid; (meth) acrylic acid 2-hydroxyethyl, (meth) acrylic acid 2- Hydroxyl, 4-hydroxybutyl (meth) acrylate, N-methylolacrylamide, hydroxyl group-containing monomers such as allyl alcohol; dimethylaminoethyl (meth) acrylate, diethylaminoethyl (meth) acrylate, dimethylaminopropyl (meth) acrylate, etc. Tertiary amino group-containing monomers; amide group-containing monomers such as acrylamide and methacrylamide; N-methyl (meth) acrylamide, N-ethyl (meth) acrylamide, N-methoxymethyl (meth) acrylami , N- ethoxymethyl (meth) acrylamide, N-t-butyl (meth) acrylamide, N- octyl (meth) N- substituted amide group-containing monomers such as acrylamide, epoxy group-containing monomers such as glycidyl methacrylate. One or more of these copolymerizable monomer components can be used. The amount of these copolymerizable monomers used is preferably 70% by weight or less, more preferably 40% by weight or less of the total monomer components.

  The acrylic polymer can be obtained by subjecting a single monomer or a mixture of two or more monomers to polymerization. The polymerization can be performed by any method such as solution polymerization, emulsion polymerization, bulk polymerization, suspension polymerization and the like. The weight average molecular weight (Mw) of the acrylic polymer is preferably 500,000 to 1,500,000, more preferably 800,000 to 1,200,000. Moreover, it is preferable that the dispersion degree (Mw / Mn) of a weight average molecular weight (Mw) and a number average molecular weight (Mn) is 6-10.

The weight average molecular weight is a value converted by standard polystyrene by the GPC method. As a GPC main body, HLC-8120GPC manufactured by Tosoh Corporation is used, and a data processing using a column temperature of 40 ° C., a pump flow rate of 0.5 ml / min, and a detector RI is performed using a standard polystyrene calibration curve (molecular weight known in advance). (Calibration at 500 to 20.6 million), and the molecular weight was determined from the converted molecular weight.
Column used: TSKgel GMH-H (S) x 2 (Tosoh Corporation)
Mobile phase: Tetrahydrofuran Injection volume: 100 μl
Sample concentration: 1.0 g / l (tetrahydrofuran solution)
The degree of dispersion was calculated as the ratio of the weight average molecular weight to the number average molecular weight. The number average molecular weight was measured by the same method as the weight average molecular weight.

  The acrylic pressure-sensitive adhesive can appropriately contain a crosslinking agent. For example, an isocyanate type crosslinking agent, an epoxy crosslinking agent, an aziridine type crosslinking agent, a chelate type crosslinking agent, etc. are mentioned.

  Although the usage-amount of a crosslinking agent in particular is not restrict | limited, For example, 0.1-15 weight part is preferable with respect to 100 weight part of said acrylic polymers, and 1-10 weight part is more preferable. If the amount is less than 0.1 parts by weight, the cohesive force is insufficient, and if it exceeds 15 parts by weight, the adhesive force is insufficient.

  The layered silicate is not particularly limited.For example, saponite, smectite, saconite, stevensite, hectorite, margarite, talc, phlogopite, muscovite, chrysotile, chlorite, vermiculite, kaolinite, xanthite Examples include sophilite, dickite, nacrite, vilophyllite, montmorillonite, hydelite, nontonite, tetrasilic mica, sodium teniolite, antigolite, halloysite, etc.In particular, it is more preferable to use montmorillonite and smectite. is there. The layered silicate may be either a natural product or a synthetic product, and there is no problem even if one or more of these are used simultaneously.

  The average particle size of the layered silicate is preferably 0.01 to 100 μm, more preferably 0.05 to 10 μm, and the aspect ratio is preferably 20 to 500, more preferably 50 to 200.

  The amount of the layered silicate used is not particularly limited, but the amount used is appropriately determined in order to obtain heat resistance. For example, the adhesive surface of the adhesive layer of the tape is affixed to a stainless steel plate, the application area is 10 mm × 20 mm, the working temperature is 175 ° C., the load is 25 g, the displacement distance after 1 hour (shear holding force: JIS Z0237) According to a preferred embodiment, adjustment is made so that the layered silicate is added so that the measurement is 0.3 mm or less. Specifically, the layered silicate is preferably 1 to 40 parts by weight, more preferably 10 to 30 parts by weight, and still more preferably 10 to 20 parts by weight with respect to 100 parts by weight of the acrylic polymer. . When the amount is less than 1 part by weight, heat resistance is hardly exhibited. On the other hand, if it exceeds 40 parts by weight, the adhesiveness of the adhesive is lost.

  In addition to the above-described components, the pressure-sensitive adhesive may contain various conventionally known additives such as various initiators, tackifiers, anti-aging agents, fillers, colorants, chain transfer agents, and plasticizers. Also good.

  The solvent used for the preparation of the pressure-sensitive adhesive layer is not particularly limited, but an organic solvent is usually used. As an organic solvent, what can melt | dissolve an adhesive composition uniformly may be sufficient at the surface of the coating-film stability at the time of film forming. Examples of the organic solvent include butane, hexane, heptane, toluene, o-xylene, m-xylene, p-xylene, cyclohexane, methanol, ethanol, isopropyl alcohol, 1-pentanol, cyclohexanol, 2-methylcyclohexanol, Diethyl ether, isopropyl ether, dibutyl ether, dibenzyl ether, tetrahydrofuran, acetone, methyl ethyl ketone, methyl isobutyl ketone, 2-heptanone (methylpentyl ketone), diisobutyl ketone, cyclohexanone, methylcyclohexanone, cyclopentanone, amyl acetate, methyl acetate, Ethyl acetate, propyl acetate, butyl acetate, N, N-dimethylformamide (DMF), N, N-dimethylacetamide (DMAc), N-methylpyrrole Down, 2-methoxyethanol, 2-ethoxyethanol, and 2-butoxyethanol and the like. As the organic solvent, ethyl acetate, toluene, xylene and the like are preferable. Depending on the solvent, the pressure-sensitive adhesive composition is usually prepared in a solution having a solid concentration of 5 to 50% by weight, preferably 5 to 30% by weight, and more preferably 10 to 25% by weight.

  Although the thickness of the adhesive layer formed is not specifically limited, Usually, about 2-100 micrometers is preferable, about 5-50 micrometers is more preferable, and 10-30 micrometers is still more preferable. If it exceeds 100 μm, it may be too thick and difficult to handle.

  In the method for forming the pressure-sensitive adhesive layer of the present invention, the pressure-sensitive adhesive composition is applied on a supporting substrate to form a pressure-sensitive adhesive composition layer. Various methods can be adopted as the forming method. For example, when a continuous coating apparatus is used for forming the pressure-sensitive adhesive composition layer, for example, the pressure-sensitive adhesive composition (solution) is continuously supplied and continuously from a discharge means such as a die attached to the tip of the apparatus. The method of extruding to a thin layer on a sheet | seat base material is mentioned. When a batch method is adopted as a method for forming the pressure-sensitive adhesive composition layer, the pressure-sensitive adhesive composition (solution) is cast on the support substrate, and the applicator, Meyer bar, knife A method of forming with a coater is mentioned. Thus, after laminating | stacking the thinned adhesive composition on a support base material, it heats and removes a solvent.

  The thickness of the pressure-sensitive adhesive tape of the present invention is preferably at least 5 μm or more in order to prevent breakage or tearing, and further preferably 10 to 100 μm in view of suitable handling properties.

  The shear holding force of the pressure-sensitive adhesive layer is determined by attaching the pressure-sensitive adhesive surface of the pressure-sensitive adhesive layer to a stainless steel plate, and pressing and bonding the pressure-sensitive adhesive layer by reciprocating a 2 kg rubber roller so that the adhesion area is 10 mm × 20 mm. Evaluation was performed by measuring a displacement distance (shear holding force: measured according to JIS Z0237) (mm) at 175 ° C. with a load of 25 g after 1 hour. The shear holding force is preferably 0.3 mm or less, and more preferably 0.2 mm or less. If the shear holding force exceeds 0.3 mm, element winding may be loosened.

  Next, the aluminum electrolytic capacitor of the present invention will be described. The aluminum electrolytic capacitor was drawn from a capacitor element constituted by winding an anode foil and a cathode foil through a separator, and an anode and a cathode foil, respectively. It is comprised by the terminal, the sealing material which seals these, and a case. Here, as the tape for winding the capacitor element, the aluminum electrolytic capacitor element winding tape is used. By using this tape, it is possible to obtain an aluminum electrolytic capacitor capable of preventing a decrease in capacitance due to loose winding of the capacitor element even in a high temperature atmosphere.

  Hereinafter, although the present invention is explained based on an example, the present invention is not limited to these. Hereinafter, “parts” means parts by weight.

<Example 1>
A biaxially stretched polyphenylene sulfide film (trade name: Torelina 3030, manufactured by Toray, thickness: 25 μm) was used as a supporting substrate.

  The pressure-sensitive adhesive layer was prepared by the following method. First, an acrylic polymer which was a base polymer obtained from a monomer mixed solution consisting of 100 parts of n-butyl acrylate and 5 parts of acrylic acid was prepared. To 100 parts of this acrylic polymer, 10 parts of montmorillonite (trade name: Kunipia G, manufactured by Kunimine Kogyo Co., Ltd., average particle size: 0.1 μm) which is a layered silicate is added, and further 100 parts of the acrylic polymer. On the other hand, 1 part of an epoxy-based crosslinking agent (trade name: Tetrad C, manufactured by Mitsubishi Gas Chemical Co., Inc.) and 500 parts of toluene as a solvent were added to prepare an acrylic pressure-sensitive adhesive solution. This acrylic pressure-sensitive adhesive solution was applied onto a support substrate and dried so as to form a pressure-sensitive adhesive layer having a thickness of 20 μm, thereby preparing a pressure-sensitive adhesive layer.

<Example 2>
A biaxially stretched polyester film (for example, trade name: LCP film, manufactured by Sumitomo Chemical Co., Ltd., thickness: 25 μm) was used as the support substrate.

  The pressure-sensitive adhesive layer was prepared by the following method. First, an acrylic polymer that was a base polymer obtained from a monomer mixed solution consisting of 70 parts of n-butyl acrylate, 25 parts of 2-ethylhexyl acrylate, and 5 parts of acrylic acid was prepared. To 100 parts of this acrylic polymer, 15 parts of montmorillonite (trade name: Kunipia G, manufactured by Kunimine Kogyo Co., Ltd., average particle size: 0.1 μm), which is a layered silicate, is added, and further 100 parts of the acrylic polymer. On the other hand, 3 parts of an epoxy-based crosslinking agent (trade name: Tetrad C, manufactured by Mitsubishi Gas Chemical Co., Inc.) and 500 parts of toluene as a solvent were added to prepare an acrylic pressure-sensitive adhesive solution. This acrylic pressure-sensitive adhesive solution was applied onto a support substrate and dried so as to form a pressure-sensitive adhesive layer having a thickness of 20 μm, thereby preparing a pressure-sensitive adhesive layer.

<Comparative Example 1>
A pressure-sensitive adhesive tape was produced in the same manner as in Example 1 except that the pressure-sensitive adhesive layer was prepared without adding the layered silicate in Example 1.

<Comparative example 2>
A pressure-sensitive adhesive tape was produced in the same manner as in Example 2 except that the pressure-sensitive adhesive layer was prepared without adding the layered silicate in Example 2.

  Table 1 shows the evaluation results of the pressure-sensitive adhesive layers obtained in Examples and Comparative Examples.

  By using the pressure-sensitive adhesive tape of the present invention, it was confirmed that the shear holding force under a high temperature atmosphere was 0.3 mm or less, and it was confirmed that it had high heat resistance. For this reason, it was confirmed that it was possible to prevent the occurrence of defects such as loosening of the element even when the aluminum electrolytic capacitor element was used to prevent high temperature and was subjected to high temperature treatment. On the other hand, in the comparative example, the shear holding force exceeded 0.3 mm, and it was confirmed that element loosening due to high temperature treatment was likely to occur.

Claims (4)

An aluminum electrolytic capacitor element winding tape having an adhesive layer on one side of a support substrate,
The tape for winding an aluminum electrolytic capacitor element, wherein the pressure-sensitive adhesive layer contains a pressure-sensitive adhesive and a layered silicate.   The tape for winding an aluminum electrolytic capacitor element according to claim 1, wherein the pressure-sensitive adhesive layer contains 1 to 40 parts by weight of a layered silicate with respect to 100 parts by weight of the pressure-sensitive adhesive.   The adhesive surface of the pressure-sensitive adhesive layer is affixed to a stainless steel plate, the applied area is 10 mm × 20 mm, the operating temperature is 175 ° C., a load of 25 g is applied, and the displacement distance (shear holding force) after 1 hour is 0.3 mm or less. The tape for winding an aluminum electrolytic capacitor element according to claim 1 or 2.   The aluminum electrolytic capacitor formed using the aluminum electrolytic capacitor element winding stop tape in any one of Claims 1-3.