JP2012001673A - Addition-curable silicone composition and capacitor using the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an addition-curable silicone composition excellent in adhesivity with aluminum and a phenol resin; and to provide a capacitor using the same for sealing an armor case and a sealing member.SOLUTION: The addition-curable silicone composition is constituted of (A) an organopolysiloxane, (B) an alkoxysilane having alkenyl groups at the terminals, (C) an organopolysiloxane, and (D) a platinum group-metallic catalyst. The addition-curable silicone composition is filled and cured in a jointing part of an armor case 1 and a sealing member 2 of a capacitor. For the armor case 1 and the sealing member 2, a pair of projections 11, 12 of the armor case 1 interpose a projection 21 of the circumference of the sealing member 2. The addition-curable silicone composition is filled and cured in a recess 22 of the circumference of the sealing member 2. The mechanical strength of the armor case 1 and the sealing member 2 is secured by caulking, and the airtightness and gas permeability is secured by the addition-curable silicone composition 3.

Description

  The present invention relates to a curable silicone composition, and more particularly to an addition-curable silicone composition that forms a cured silicone product having excellent adhesion to metals and resins, and a capacitor using the same.

  Conventionally, a capacitor is manufactured by winding a capacitor element formed by inserting a sealing member together with the capacitor element into an outer case formed of a bottomed cylindrical metal or resin, and sealing the opening. The sealing member is formed with a through-hole for penetrating and holding the lead terminal drawn from the capacitor element. Or the thing of the state which embedded the external terminal connected with the terminal pulled out from the capacitor | condenser element in the sealing member is formed. In the sealing process, a method of crimping the outer case to the sealing member by applying a molding pressure by pressing a rotary molded body is used. In order to improve the sealing performance, there is a manufacturing method in which a resin is applied after the sealing member is inserted into an outer case formed of metal or resin, or after the caulking process after insertion.

  “Addition-curing silicone composition” used as one of the resins forms a gel-like, rubber-like, or resin-like silicone cured product with excellent electrical properties, heat resistance, weather resistance, and stress relaxation properties. Therefore, it is used as a sealant, buffer, anti-vibration agent, and filler for electrical / electronic parts. However, a cured silicone obtained by curing these curable silicone compositions has a problem of poor adhesion to metals or resins. For this reason, there are cases where these silicone compositions are not suitable for sealing or bonding electrical / electronic parts formed of metal or resin.

  In order to improve the adhesion of the addition-curable silicone, conventionally, studies have been made to add an adhesion-imparting component to the curable silicone resin to develop the adhesion. For example, an addition-curable silicone rubber composition containing an alkoxysilyl group-containing hydrogensiloxane (see Patent Document 1), an addition-curable silicone rubber composition containing an epoxy group-containing hydrogensiloxane (see Patent Document 2), etc. Has been proposed. However, it is difficult to self-adhere to some metals and resins, and adhesiveness may not be exhibited unless a primer component is used.

  On the other hand, as an addition-curable silicone adhesive that self-adheres to a difficult-to-adhere substrate, a technique of adding a nitrogen compound (see Patent Document 3), or an organic catalyst as a hydrolysis catalyst for alkoxysilane added as an adhesion-imparting material Techniques for adding tin compounds, organic titanium compounds, organoaluminum compounds, and zirconium compounds have been developed and are publicly known.

  However, these techniques can affect the curability of addition curable silicone adhesives. When a nitrogen compound is added to the addition-curable silicone adhesive, the catalytic ability of the platinum atom that is the addition reaction catalyst is significantly hindered, and the curability becomes very unstable. Moreover, when an organotin compound, an organotitanium compound, an organoaluminum compound, a zirconium compound, etc. are added similarly, the organohydrogensiloxane in the addition-curable silicone adhesive is deactivated.

  In addition, a technique for adding an alkoxysilane having an alkenyl group at the terminal, such as acryloxy functional alkoxysilane or methacryloxy functional alkoxysilane (see Patent Document 4) is known. However, when an alkoxysilane having an alkenyl group at the terminal is used, it is consumed by reacting with hydrogen siloxane in the presence of a platinum catalyst, and the curability becomes very unstable. When an alkoxysilane having an alkenyl group at the terminal is added, it is necessary to define an appropriate amount of hydrogen siloxane added to the amount used.

Japanese Patent Publication No.53-21026 Japanese Patent Publication No.53-13508 Japanese Patent Publication No. 52-147963 Patent publication 2008-528788

  The present invention has been made in view of the above circumstances, and maintains a curing stability while containing an alkoxysilane having an alkenyl group at the terminal, and exhibits good adhesiveness even on difficult-to-adhere substrates. An object of the present invention is to provide an addition-curable silicone rubber adhesive composition suitable for sealing. Another object of the present invention is to provide a sealing structure that improves sealing performance and a capacitor using the same, in sealing a capacitor that uses an outer case formed of metal or resin.

  In this specification, the term “sealing” is not limited to the purpose of ensuring the sealing performance at the sealing portion of the capacitor, but means all uses for filling gaps between members such as adhesion and sealing of each member constituting the capacitor. .

  As a result of intensive studies to achieve the above-mentioned object, the present inventor made a difficult-to-adhesive substrate by using an addition-curable silicone composition containing the following components (A) to (D). In contrast, the inventors have found that the present invention exhibits excellent adhesion and is excellent in the stability of curing, and has led to the present invention.

The curable silicone composition of the present invention is
(A) Content of cyclic diorganosiloxane having a viscosity at 25 ° C. of 50 to 100,000 mPa · s, an average of two or more silicon atom-bonded alkenyl groups in one molecule, and a polymerization degree of 4 to 10 100 parts by weight of an organopolysiloxane having a content of 0.1% by weight or less,
(B) 0.01 to 10 parts by weight of alkoxysilane having a terminal alkenyl group in the molecule;
(C) An organopolysiloxane having an average of two or more silicon-bonded hydrogen atoms in one molecule is added to one mole of silicon-bonded alkenyl group in component (A) and one mole of alkenyl group in component (B). An amount in which silicon-bonded hydrogen atoms in the component are 0.8 to 1.5 mol,
(D) The amount of platinum group metal catalyst in which 0.01 to 1000 ppm by weight of platinum group metal in this component with respect to the total amount of component (A), component (B) and component (C). ,
It is characterized by comprising.

Hereinafter, the curable silicone composition of the present invention will be described in detail.
The organopolysiloxane of component (A) is the main ingredient of this composition. The viscosity of component (A) at 25 ° C. is in the range of 50 to 100,000 centipoise, particularly preferably in the range of 100 to 50,000 centipoise. This is because when the viscosity at 25 ° C. is less than 50 centipoise, the physical properties of the resulting silicone cured product are remarkably deteriorated, and when this exceeds 100,000 centipoise, the handling workability of the resulting composition is improved. This is because remarkably decreases. Such component (A) contains an average of two or more silicon-bonded alkenyl groups per molecule.

  Examples of the silicon atom-bonded alkenyl group include a vinyl group, an allyl group, a butenyl group, a pentenyl group, and a hexenyl group, and a vinyl group is particularly preferable. Examples of silicon-bonded organic groups other than alkenyl groups in component (A) include, for example, methyl groups, ethyl groups, propyl groups, butyl groups, pentyl groups, hexyl groups and other alkyl groups, cyclopentyl groups, cyclohexyl groups, and other cycloalkyl groups. Aryl groups such as alkyl groups, phenyl groups, tolyl groups and xylyl groups, aralkyl groups such as benzyl groups and phenethyl groups, and halo-substituted alkyl groups such as 3,3,3-trifluoropropyl groups and 3-chloropropyl groups. In particular, a methyl group and a phenyl group are preferable.

  The molecular structure of the component (A) is not limited, and examples thereof include linear, branched, partially branched linear, network, and resinous. The component (A) is a single polymer or copolymer having these molecular structures or a mixture thereof, but preferably has at least a linear molecular structure.

(B) The alkoxysilane which has an alkenyl group at the terminal of a component acts as an adhesion imparting material for this component. The component (B) is used at a concentration of 0.1 to 10% by weight of the total weight of the components (A) to (D). This is because if the content is less than 0.1% by weight, the resulting composition does not exhibit sufficient adhesiveness, and if it is added in excess of 10% by weight, the physical properties of the resulting cured product are reduced. The component (B) is, for example, vinyl functional alkoxysilane, allyl functional alkoxysilane, hexenyl functional alkoxysilane, acryloxy functional alkoxysilane, or methacryloxy functional alkoxysilane.

  Some representative examples of suitable alkoxysilanes are, for example, vinyltrimethoxysilane, vinyltriethoxysilane, allyltrimethoxysilane, hexenyltrimethoxysilane, 3-acryloxypropyldimethylmethoxysilane, 3-acryloxypropylmethyldimethoxy. Silane, 3-acryloxypropyltrimethoxysilane, 3-methacryloxymethyldimethylethoxysilane, 3-methacryloxymethyltriethoxysilane, 3-methacryloxymethyltrimethoxysilane, 3-methacryloxypropyldimethylethoxysilane, 3-methacrylic Loxypropyldimethylmethoxysilane, 3-methacryloxypropylmethyldiethoxysilane, 3-methacryloxypropylmethyldimethoxysilane, 3-methacryloxypropyltri Tokishishiran, 3-methacryloxypropyl trimethoxy silane, 3-methacryloxypropyl tris tetraisopropoxysilane and 3-methacryloxypropyl tris methoxyethoxy silane.

  The organopolysiloxane of component (C) acts as a crosslinking agent for the composition. Such a component (C) contains an average of 2 or more silicon-bonded hydrogen atoms in one molecule. The silicon-bonded organic group in the component (C) is not limited, and examples thereof include alkyl groups such as methyl, ethyl, propyl, butyl, pentyl, and hexyl groups, and cycloalkyl groups such as cyclopentyl and cyclohexyl groups. Aryl groups such as phenyl group, tolyl group and xylyl group, aralkyl groups such as benzyl group and phenethyl group, halo-substituted alkyl groups such as 3,3,3-trifluoropropyl group and 3-chloropropyl group, Particularly preferred are a methyl group and a phenyl group. The molecular structure of the component (C) is not limited, and examples thereof include linear, branched, partially branched linear, cyclic, network, and resinous. Component (C) is a single polymer or copolymer having these molecular structures, or a mixture thereof.

  The amount of component (C) is such that the molar ratio of silicon atom-bonded hydrogen atoms to silicon atom-bonded alkenyl groups of component (A) and alkenyl groups of component (B) is 0.8 to 1.5. This is because a composition in which the molar ratio of the silicon atom-bonded hydrogen atom of component (C) to the silicon atom-bonded alkenyl group of component (A) and the alkenyl group of component (B) is less than 0.8 is not sufficiently cured. Moreover, when this is more than 1.5, it will foam at the time of hardening, or it will cause a time-dependent change of a physical property.

  The platinum group metal catalyst of component (D) is a catalyst for accelerating the curing of the present composition. For example, chloroplatinic acid, an alcohol solution of chloroplatinic acid, a complex of platinum and olefin, platinum and divinyltetramethyl Examples include complexes with disiloxane, palladium compounds, and rhodium compounds.

  The blending amount of the component (D) is an amount such that the platinum metal of this component is in the range of 0.01 to 1000 ppm by weight with respect to the sum of the components (A), (B), and (C), In particular, the amount is preferably in the range of 0.1 to 500 ppm. This is because the composition in which the platinum metal of the component (D) with respect to the total of the components (A), (B), and (C) is less than 0.01 ppm by weight is not sufficiently cured. In addition, this is because it is uneconomical in an amount exceeding 1000 ppm.

  The addition-curable silicone composition of the present invention can be prepared by uniformly mixing the components (A) to (D). In the addition-curable silicone composition of the present invention, as long as the object of the present invention is not impaired, as other optional components, for example, fumed silica, fumed silica hydrophobized with an organosilicon compound, talc, mica, etc. Addition reaction inhibitors such as fillers, acetylene compounds, hydrazine compounds, phosphine compounds, mercaptan compounds, pigments, dyes, fluorescent dyes, heat-resistant additives, flame retardants, plasticizers, alkenyl groups at the ends Examples include adhesion-imparting agents other than the alkoxysilanes.

  The curable properties of the silicone cured product obtained by curing the addition-curable silicone composition of the present invention are not limited, and examples thereof include silicone gel, silicone rubber, and silicone resin. , Its adhesiveness is good.

  The method for curing the addition-curable silicone composition of the present invention is not limited, and examples thereof include a method of leaving the curable silicone composition at room temperature and a method of heating to 50 to 200 ° C. Although the cured silicone obtained in this way can be handled alone, it is generally handled in a state of being in close contact with the substrate, for example, in a state where the capacitors are sealed or sealed. It is preferable. The cured silicone is colorless and transparent or translucent, but can be arbitrarily adjusted by blending a pigment or dye.

  The capacitor according to the present invention is characterized in that the above addition-curable silicone composition is used as a sealing portion. Specifically, in a capacitor in which a capacitor element is housed in a cylindrical outer case formed of metal or resin, and an opening of the outer case is sealed with a sealing member, the sealing member and the outer case are the additional curing type. It is characterized by sealing with a silicone composition.

The following configuration is also one embodiment of the present invention.
(1) The sealing structure of the outer case and the sealing member is fixed by deformation of the opening of the outer case.
(2) In the sealing structure of the outer case and the sealing member, the peripheral portion of the sealing member is sandwiched by a pair of convex portions formed on the inner surface of the outer case.
(3) In the sealing structure of the outer case and the sealing member, the convex portion formed on the inner surface of the outer case is press-fitted into the concave portion formed on the end surface of the sealing member.
(4) A recess is formed on the outer peripheral surface of the sealing member, and the addition-curable silicone composition is filled and cured in the recess.
(5) The sealing member is provided with a gas permeable hole penetrating the inside and outside of the outer case, and the gas permeable hole is sealed with the curable silicone composition.
(6) The exterior case is made of an oval, elliptical, or polygonal cylindrical member, and the sealing member is made of a plate-like member that closes the opening of the cylindrical member. Furthermore, a bottomed cylindrical shape may be used, and a pipe shape may be used.
(7) When using an elastic sealing member having a through hole for penetrating and holding the lead terminal, or when using a hard sealing member embedded with an external terminal, the lead terminal and the external terminal are sealed. The addition curable silicone composition is filled and cured in a contact surface with the member or / and a gap between the lead terminal or the external terminal and the through hole.
(8) In the sealing structure of the exterior case and the sealing member, the exterior case and the sealing member are partially fixed by welding.

  The addition-curable silicone composition of the present invention is a cured silicone product that has excellent adhesion to difficult-to-bond substrates such as dissimilar materials and has excellent curing stability, such as adhesion between aluminum and phenolic resin or polyphenylene sulfide resin. It has the feature of forming. As a result, by sealing with the addition-curable silicone composition of the present invention, it is possible to provide a capacitor with a high sealing performance at the sealing portion.

  The capacitor of the present invention uses the above addition curable silicone composition, and the mechanical strength between the outer case and the sealing member is secured by caulking or welding, and the airtightness and gas permeability are the addition curable silicone. The composition ensures. Thus, the sealing performance as a whole can be improved by providing fixing and sealing of the sealing member as individual functions.

The longitudinal cross-sectional view which shows the structure of the capacitor | condenser of Example 4 of this invention. The longitudinal cross-sectional view which shows the structure of the capacitor | condenser of Example 5 of this invention. The longitudinal cross-sectional view which shows the 1st modification of the capacitor | condenser of this invention. The horizontal sectional view which shows an example of the gas permeation hole part in the capacitor | condenser of Example 6 of this invention. The horizontal sectional view which shows the other example of the gas permeation hole part in the capacitor | condenser of Example 6 of this invention.

  The addition reaction type silicone composition of the present invention will be described in detail with reference to examples. In addition, the viscosity in an Example is the value measured in 25 degreeC. Moreover, the hardness and adhesiveness of the silicone cured product were measured as follows.

(a) Hardness of cured silicone After 8 g of addition-curable silicone composition was poured into an aluminum cup having a diameter of 45 mm and a height of 12 mm, this was heated at 80 ° C. for 30 minutes to form a cured silicone. The silicone cured product was cooled to 25 ° C. and measured using a JIS A hardness meter.

(b) Adhesiveness of cured silicone product 1g of addition curable silicone composition was cured on aluminum test piece (A1050P) and phenolic resin, and the cured product was cut upward with a cutter at the edge of the cured product. The fracture surface was observed. As the evaluation method, the case where the cured product was broken was rated as “◯” because the adhesive strength was strong, the case where the cured product was completely removed from the adherend was evaluated as “poor”, and the case where the rubber was partially broken was evaluated as “Δ”. The results are shown in Table 1.

In Example 1, the following materials were uniformly mixed to prepare an addition curable silicone composition.
(1) 100 parts by weight of dimethylpolysiloxane blocked with dimethylvinylsiloxy group at both ends of the molecular chain having a viscosity of 600 mPa · s (vinyl group content = 0.38 wt%).
(2) 11.4 parts by weight of fumed silica whose surface is hydrophobized with hexamethyldisilazane and the specific surface area is 200 m 2 / g.
(3) 5.71 parts by weight of acryloxypropyltrimethoxysilane.
(4) 2.59 parts by weight of a trimethylsiloxy-capped methylhydrogensiloxane having a viscosity of 1.9 mPa · s (content of silicon-bonded hydrogen atoms = 0.72% by weight).
However, the molar ratio of silicon-bonded hydrogen atoms to alkenyl groups of the organopolysiloxane and acryloxypropyltrimethoxysilane is 1.00.
(5) 2.29 parts by weight of a complex of platinum and divinyltetramethyldisiloxane having a platinum concentration of 0.5% by weight.

  The viscosity of this addition-curable silicone composition was 5,600 centipoise, and the handling workability was good. This addition-curable silicone composition was heated at 80 ° C. for 30 minutes to form a cured silicone product. The hardness and adhesiveness of the cured silicone were observed. These results are shown in Table 1.

In Example 2, an addition-curable silicone composition was prepared by uniformly mixing the following materials.
(1) 100 parts by weight of dimethylpolysiloxane blocked with dimethylvinylsiloxy group at both ends of the molecular chain having a viscosity of 600 mPa · s (vinyl group content = 0.38 wt%).
(2) 11.4 parts by weight of fumed silica whose surface is hydrophobized with hexamethyldisilazane and the specific surface area is 200 m 2 / g.
(3) 5.71 parts by weight of acryloxypropyltrimethoxysilane.
(4) 3.11 parts by weight of a trimethylsiloxy-blocked methylhydrogensiloxane having a viscosity of 1.9 mPa · s (content of silicon-bonded hydrogen atoms = 0.72% by weight).
However, the molar ratio of silicon atom-bonded hydrogen atoms to alkenyl groups of the organopolysiloxane and acryloxypropyltrimethoxysilane is 1.20.
(5) 2.29 parts by weight of a complex of platinum and divinyltetramethyldisiloxane having a platinum concentration of 0.5% by weight.

  This addition curable silicone composition had a viscosity of 5,400 centipoise and good handling workability. This addition-curable silicone composition was heated at 80 ° C. for 30 minutes to form a cured silicone product. The hardness and adhesiveness of the cured silicone were observed. These results are shown in Table 1.

In Example 3, an addition curable silicone composition was prepared by uniformly mixing the following materials.
(1) 100 parts by weight of dimethylpolysiloxane blocked with dimethylvinylsiloxy group at both ends of the molecular chain having a viscosity of 600 mPa · s (vinyl group content = 0.38 wt%).
(2) 11.4 parts by weight of fumed silica whose surface is hydrophobized with hexamethyldisilazane and the specific surface area is 200 m 2 / g.
(3) 5.71 parts by weight of acryloxypropyltrimethoxysilane.
(4) 3.89 parts by weight of a trimethylsiloxy-capped methylhydrogensiloxane having a viscosity of 1.9 mPa · s (content of silicon-bonded hydrogen atoms = 0.72% by weight).
However, the molar ratio of silicon atom-bonded hydrogen atoms to alkenyl groups of the organopolysiloxane and acryloxypropyltrimethoxysilane is 1.50.
(5) 2.29 parts by weight of a complex of platinum and divinyltetramethyldisiloxane having a platinum concentration of 0.5% by weight.

  This addition curable silicone composition had a viscosity of 5,400 centipoise and good handling workability. This addition-curable silicone composition was heated at 80 ° C. for 30 minutes to form a cured silicone product. The hardness and adhesiveness of the cured silicone were observed. These results are shown in Table 1.

In Example 4, the following materials were uniformly mixed to prepare an addition-curable silicone composition.
(1) 100 parts by weight of dimethylpolysiloxane blocked with dimethylvinylsiloxy group at both ends of the molecular chain having a viscosity of 600 mPa · s (vinyl group content = 0.38 wt%).
(2) 11.4 parts by weight of fumed silica whose surface is hydrophobized with hexamethyldisilazane and the specific surface area is 200 m 2 / g.
(3) 5.71 parts by weight of acryloxypropyltrimethoxysilane.
(4) 2.07 parts by weight of a trimethylsiloxy-capped methylhydrogensiloxane having a viscosity of 1.9 mPa · s (content of silicon-bonded hydrogen atoms = 0.72% by weight).
However, the molar ratio of silicon-bonded hydrogen atoms to alkenyl groups of the organopolysiloxane and acryloxypropyltrimethoxysilane is 0.80.
(5) 2.29 parts by weight of a complex of platinum and divinyltetramethyldisiloxane having a platinum concentration of 0.5% by weight.

  The viscosity of this addition-curable silicone composition was 5,800 centipoise, and the handling workability was good. This addition-curable silicone composition was heated at 80 ° C. for 30 minutes to form a cured silicone product. The hardness and adhesiveness of the cured silicone were observed. These results are shown in Table 1.

In Example 5, the following materials were uniformly mixed to prepare an addition-curable silicone composition.
(1) 100 parts by weight of dimethylpolysiloxane blocked with dimethylvinylsiloxy group at both ends of the molecular chain having a viscosity of 600 mPa · s (vinyl group content = 0.38 wt%).
(2) 11.4 parts by weight of fumed silica whose surface is hydrophobized with hexamethyldisilazane and the specific surface area is 200 m 2 / g.
(3) 5.71 parts by weight of acryloxypropyltrimethoxysilane.
(4) 3.89 parts by weight of a trimethylsiloxy-capped methylhydrogensiloxane having a viscosity of 1.9 mPa · s (content of silicon-bonded hydrogen atoms = 0.72% by weight).
However, the molar ratio of silicon-bonded hydrogen atoms to alkenyl groups of the organopolysiloxane and acryloxypropyltrimethoxysilane is 0.80.
(5) 2.29 parts by weight of a complex of platinum and divinyltetramethyldisiloxane having a platinum concentration of 0.5% by weight.
(6) 61.65 parts by weight of wet crushed mica YM-21S (mascobite, average particle size 23 μm, aspect ratio 70) manufactured by Yamaguchi Mica.

  The viscosity of this addition-curable silicone composition was 19,500 centipoise, and the handling workability was good. This addition-curable silicone composition was heated at 80 ° C. for 30 minutes to form a cured silicone product. The hardness and adhesiveness of the cured silicone were observed. These results are shown in Table 1.

[Comparative Example 1]
As Comparative Example 1, an addition curable silicone composition was prepared by uniformly mixing the following materials.
(1) 100 parts by weight of dimethylpolysiloxane blocked with dimethylvinylsiloxy group at both ends of the molecular chain having a viscosity of 600 mPa · s (vinyl group content = 0.38 wt%).
(2) 11.4 parts by weight of fumed silica whose surface is hydrophobized with hexamethyldisilazane and the specific surface area is 200 m 2 / g
(3) 5.71 parts by weight of acryloxypropyltrimethoxysilane.
(4) 1.81 parts by weight of trimethylsiloxy-capped methylhydrogensiloxane having a viscosity of 1.9 mPa · s (content of silicon-bonded hydrogen atoms = 0.72% by weight).
However, the molar ratio of silicon atom-bonded hydrogen atoms to alkenyl groups of the organopolysiloxane and acryloxypropyltrimethoxysilane is 0.70.
(5) 2.29 parts by weight of a complex of platinum and divinyltetramethyldisiloxane having a platinum concentration of 0.5% by weight.

  This addition curable silicone composition had a viscosity of 5,400 centipoise and good handling workability. This addition-curable silicone composition was heated at 80 ° C. for 30 minutes to form a cured silicone product. The hardness and adhesiveness of the cured silicone were observed. These results are shown in Table 1.

[Comparative Example 2]
As Comparative Example 2, an addition curable silicone composition was prepared by uniformly mixing the following materials.
(1) 100 parts by weight of dimethylpolysiloxane blocked with dimethylvinylsiloxy group at both ends of the molecular chain having a viscosity of 600 mPa · s (vinyl group content = 0.38 wt%).
(2) 11.4 parts by weight of fumed silica whose surface is hydrophobized with hexamethyldisilazane and the specific surface area is 200 m 2 / g.
(3) 0 parts by weight of acryloxypropyltrimethoxysilane (not added).
(4) 1.81 parts by weight of trimethylsiloxy-capped methylhydrogensiloxane having a viscosity of 1.9 mPa · s (content of silicon-bonded hydrogen atoms = 0.72% by weight).
However, the molar ratio of silicon-bonded hydrogen atoms to alkenyl groups of the organopolysiloxane and acryloxypropyltrimethoxysilane is 1.00.
(5) 2.29 parts by weight of a complex of platinum and divinyltetramethyldisiloxane having a platinum concentration of 0.5% by weight.

  This addition curable silicone composition had a viscosity of 5,400 centipoise and good handling workability. This addition-curable silicone composition was heated at 80 ° C. for 30 minutes to form a cured silicone product. The hardness and adhesiveness of the cured silicone were observed. These results are shown in Table 1.

  As can be seen from Table 1 and Table 2 showing the composition of each example and comparative example, in Comparative Example 2 that does not contain the B component, it is used as a capacitor outer case and aluminum used as a capacitor sealing case. Sufficient adhesion to the phenol resin cannot be obtained. Further, in Comparative Example 1 where the molar ratio of silicon-bonded hydrogen atoms in the biterminal trimethylsiloxy-capped methylhydrogensiloxane, which is the C component, is less than 0.8 of the present invention, the composition does not cure, Does not work. In Example 5, the hardness is increased by adding mica.

  On the other hand, in Examples 1 to 3, in which the molar ratio of silicon atom-bonded hydrogen atoms in the biterminal trimethylsiloxy-capped methylhydrogensiloxane, which is the C component, was in the range of 1.0 to 1.5, the composition was sufficient. Curing and adhesion to aluminum and phenolic resin were confirmed. This example is related to the C component of the present invention because “a composition in which the molar ratio of silicon-bonded hydrogen atoms is less than 0.8 does not cure sufficiently, and if it is more than 1.5, Or the cause of changes in physical properties over time ”.

  Next, a configuration example of a capacitor using the above addition-curable silicone composition will be described with reference to the drawings. The addition curable silicone composition used in the capacitors shown in Examples 6 and below is not limited to those in Examples 1 to 3, and the compositions defined in the claims of the present invention can be used as appropriate. Moreover, although each Example showed the sealing structure of the exterior case and sealing member of a capacitor | condenser, as an exterior case used, a circular (perfect circle) cylindrical shape, an elliptical shape or an oval cylindrical shape, a rectangular tube shape These members can be used. Further, in places where sealing properties other than the outer case and the sealing member are required, for example, gaps between the sealing member and external terminals provided on the sealing member, metal members such as aluminum and copper, phenol resin, polyphenylene sulfide resin, etc. It can be widely used for joining hard members and elastic members such as rubber.

  For example, when using a sealing member made of rubber or the like in which a through hole for penetrating and holding the lead terminal drawn from the capacitor element is used, the contact surface between the lead terminal and the sealing member, or the through hole By filling and curing the addition-curable silicone composition in the gap between the lead terminal and the lead terminal, the adhesiveness can be enhanced and the sealing performance can be enhanced. In particular, the lead terminal having a shape in which a metal wire is connected to the tip of a round bar portion may cause a gap between the through hole of the sealing member and the metal wire, and the addition to the gap By filling and curing the curable silicone composition, the adhesiveness can be enhanced and the sealing performance can be further enhanced.

  In addition, even when a hard sealing member embedded with an external terminal connected to a terminal drawn from a capacitor element is used, the contact curing surface or gap between the lead terminal and the hard sealing member is filled with the addition-curable silicone composition. By curing, the adhesiveness can be improved and the sealing performance can be improved.

  FIG. 1 shows a case in which an opening of a capacitor outer case 1 having a capacitor element (not shown) inserted therein is sealed by a sealing member 2, and a gap between the two is joined by the addition-curable silicone composition 3. is there. That is, the outer case 1 is made of a bottomed cylindrical member made of aluminum, and a pair of protrusions projecting endlessly toward the inner side of the outer case 1 and over the entire inner surface of the outer case 1 at the opening edge. Portions 11 and 12 are formed. The pair of convex portions 11 and 12 are provided at intervals corresponding to the thickness of the peripheral edge of the sealing member 2, and the peripheral edge of the sealing member 2 is interposed between the two by performing a caulking process on the opening of the outer case 1. Is sandwiched between.

  The sealing member 2 is a member that is fitted inside the outer case 1 and closes the opening thereof, and has a convex portion 21 that is sandwiched between the pair of convex portions 11 and 12 of the outer case 1 at the periphery thereof. Is provided. In this case, the convex portion 21 may have the same thickness as the central portion of the sealing member 2 or is thinner than the central portion as shown in the figure, and forms the concave portion 22 in the peripheral portion of the sealing member 2. But it ’s okay. The outer case 1 and the sealing member 2 are integrally fixed by the caulking process of the outer case 1, but the airtightness required for the capacitor is not ensured only by the caulking process. The sealing member 2 is provided with an external electrode 23 connected to a capacitor element (not shown) housed in the exterior case 1.

  The gap at the joint between the outer case 1 and the sealing member 2 is sealed with the addition-curable silicone composition 3. The addition curable silicone composition 3 is filled in the recess 22 formed on the peripheral edge of the sealing member 2 in Example 1. In this case, since the depth of the concave portion 22 is larger than the thickness of the convex portion 11 of the exterior case 1 in this embodiment, the addition-curable silicone composition 3 also embeds the convex portion 11 therein. Yes. In the present invention, the convex portion 11 is embedded with the addition-curable silicone composition 3, and the convex portion 11 is not exposed to the outside, but the addition-curable silicone composition 3 has its gas permeability and desired permeation amount. The filling amount may be determined according to the above, and a part of the filling portion 11 may be exposed without embedding the convex portion 11.

  In the capacitor of the present embodiment having such a configuration, by sealing the joint portion between the outer case 1 and the sealing member 2 from the addition-curable silicone composition 3, it is possible to ensure the airtightness of the sealing portion. it can. In this case, the caulking portion has a structure in which the sealing member is sandwiched and fixed by the protrusion, and the airtightness is achieved by the resin, so that the airtightness is improved.

  In particular, in flat capacitors that use an oval outer case with a long side and a curved part, the radius of curvature differs between the long side and the curved part. Even if it is added, it is difficult to apply the forming force evenly, and the necessary airtightness may not be obtained only by the caulking process. However, in this embodiment, the sealing member is not a structure that secures airtightness only by the caulking process of the opening edge portion of the exterior case, but the airtightness is ensured by the addition-curable silicone composition. Even in the case of using, it is not necessary to separately provide a soft member such as a rubber ring. This eliminates the need for a mold or a rubber member for manufacturing the rubber ring, thereby reducing the cost. Further, there is no problem of a decrease in sealing strength due to deterioration caused by long-term use at a high temperature.

  Further, since the sealing member can be fixed by the upper and lower protrusions, it is not necessary to obtain the strength of the resin, and the range of selection for adhesiveness is widened. For example, the addition curable silicone composition of the present invention It is possible to select a resin having gas permeability. As a result, it is possible to extend the life of the capacitor by delaying the operation timing of the safety valve.

  FIG. 2 shows another embodiment of the capacitor of the present invention. In the present embodiment, one convex portion 13 is formed in the opening of the outer case 1, and this convex portion 13 is fitted into the concave portion 24 formed on the peripheral edge of the sealing member 2 by the caulking process of the outer case 1. It is a combination. Also in the present embodiment, the recess 22 is formed on the upper surface of the peripheral edge of the sealing member 2, and the addition-curable silicone composition 3 is filled in the recess 22 and cured, so that the exterior case 1 and the sealing member 2 Airtightness is ensured.

  The caulking structure between the outer case 1 and the sealing member 2 is not limited to that shown in FIGS. FIG. 3 is a modification of the embodiment of FIG. 1, using a sealing member 2 having a larger diameter than the main body of the outer case 1, and the entire peripheral edge of the sealing member 2 swells outside the main body of the outer case 1. It is sandwiched between the recesses 14.

  Also in the present embodiment, as in the sixth embodiment, the mechanical coupling strength between the outer case 1 and the sealing member 2 is ensured by the caulking process of both, and the airtightness is filled and cured in the recess 22. This is ensured by the addition-curable silicone composition 3. Therefore, the effect as shown in Example 6 is exhibited.

  In this embodiment, in order to positively use the gas permeability of the addition curable silicone composition 3, a gas permeable hole 4 is formed between the outer case 1 and the sealing member 2. The portion is closed with the addition-curable silicone composition 3. FIG. 4 shows a gas permeation having a semicircular cross section that penetrates the sealing member 2 at the end surface of the outer periphery of the sealing member 2 so that the gas permeation hole 4 is formed between the outer peripheral portion of the sealing member 2 and the inner surface of the exterior case 1. This is an example in which a hole 4 is provided. FIG. 5 shows an example in which a gas permeation hole 4 penetrating the sealing member 2 is provided in a part of the sealing member 2 (a portion where the addition-curable silicone composition 3 is filled).

  According to the present embodiment, the air permeability between the outer case 1 and the sealing member 2 can be kept constant without affecting the sealing performance of the outer case 1 and the sealing member 2 due to the crimping operation. Therefore, the gas pressure in the capacitor can be more accurately controlled in consideration of the gas permeability of the addition curable silicone composition 3 and the airtightness between the outer case 1 and the sealing member 2.

  Although the embodiments of the present invention have been described with reference to the drawings, the specific configuration is not limited to these embodiments, and modifications and additions within the scope of the present invention are included in the present invention. It is.

  For example, in the embodiment shown in FIGS. 1 to 3, the recess 22 is provided on the periphery of the sealing member 2, but the inner surface of the exterior case 1 and the periphery of the sealing member 2 are provided without providing the recess 22 on the periphery of the sealing member 2. The addition-curable silicone composition 3 may be filled and cured between the surface of the part so as to swell. In the embodiment of FIG. 2, the convex portion 13 formed on the outer case 1 and the concave portion 24 on the end surface of the sealing member 2 to which the convex portion 13 is fitted are formed in a square shape. There may be.

  Moreover, although the convex part protrudes endlessly over the whole inner surface in the Example, it is good also as a shape divided | segmented to such an extent that a sealing member can be fixed.

  Furthermore, as the shape of the outer case, it may be composed of an oval, elliptical, or polygonal cylindrical member, and may be composed of a plate-shaped member that closes the opening of the sealing member.

  In the present embodiment, the electrolytic capacitor using a bottomed cylindrical capacitor is illustrated as the outer case. However, the present invention is not limited to this, and the pipe-shaped outer case having no bottom is used, and each of the two openings is used. It is good also as a structure which pulls out a lead terminal and an external terminal.

  In this embodiment, the mechanical strength between the exterior case and the sealing member is secured by caulking, but the mechanical strength can be secured by welding all or part of the exterior case and the sealing member. Good.

  In this embodiment, an electrolytic capacitor is exemplified as the capacitor. However, the present invention is not limited to this, and an electric double layer capacitor can also be used.

DESCRIPTION OF SYMBOLS 1 ... Outer case 11, 12, 13 ... Convex part 2 ... Sealing member 21 ... Convex part 22, 24 ... Concave part 23 ... External electrode 3 ... Addition-curable silicone composition 4 ... Gas permeation hole

Claims (7)

(A) Content of cyclic diorganosiloxane having a viscosity at 25 ° C. of 50 to 100,000 mPa · s, an average of two or more silicon atom-bonded alkenyl groups in one molecule, and a polymerization degree of 4 to 10 100 parts by weight of an organopolysiloxane having a content of 0.1% by weight or less,
(B) 0.01 to 10 parts by weight of alkoxysilane having a terminal alkenyl group in the molecule;
(C) An organopolysiloxane having an average of two or more silicon-bonded hydrogen atoms in one molecule is based on 1 mole of the silicon-bonded alkenyl group in component (A) and the alkenyl group in component (B). The amount of silicon atom-bonded hydrogen atoms in this component is 0.8 to 1.5 mol,
(D) The amount of the platinum group metal catalyst in which 0.01 to 1000 ppm by weight of platinum group metal in this component with respect to the total amount of component (A), component (B) and component (C). An addition-curable silicone composition comprising: The addition-curable silicone composition according to claim 1, wherein the component (B) according to claim 1 comprises a partially hydrolyzed condensate of alkoxysilanes including an alkoxysilane having a terminal alkenyl group. The addition-curable silicone composition according to claim 1, wherein the component (B) according to claim 1 comprises acryloxypropyltrimethoxysilane. In a capacitor in which a capacitor element is housed in a cylindrical or pipe-shaped outer case formed of metal or resin, and an opening of the outer case is sealed with a front sealing member,
The capacitor | condenser which sealed the said sealing member and exterior case with the addition-curable silicone composition in any one of Claims 1-3. In a capacitor in which a capacitor element and a sealing member are inserted into a cylindrical outer case formed of metal or resin, and the front sealing member is fixed by deformation or welding of the opening of the outer case,
The capacitor | condenser which sealed the said sealing member and exterior case with the addition-curable silicone composition in any one of Claims 1-3.   5. The capacitor according to claim 4, wherein the caulking structure of the outer case and the sealing member includes a peripheral portion of the sealing member sandwiched between a pair of convex portions formed on the inner surface of the outer case. . 5. The caulking structure between the outer case and the sealing member is formed by pressing a convex portion formed on the inner surface of the outer case into a concave portion formed on the end surface of the sealing member. The capacitor described.

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