JPH084776B2 - Coating method of capacitor surface with epoxy resin - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for coating the surface of a capacitor with an epoxy resin.

[0002]

2. Description of the Related Art Epoxy resin is often used as a moisture-proof protective material for ceramic capacitors, chemical capacitors, etc. The coating of the capacitor surface with such a moisture-proof protective material involves immersing the capacitor in a moisture-proofing agent,
After pulling up, it is cured and then performed. However, during coating, the epoxy resin may adhere to the lead wires attached to the capacitor body, but if you try to mount such a capacitor on a printed circuit board, for example, the epoxy resin that adheres to the lead wires will become an obstacle. In some cases, the inconvenience may occur that wiring cannot be performed properly. Epoxy resin is
As shown by the fact that it is widely used as an adhesive, it has a strong adhesive force to the lead wire and cannot be easily removed once it is attached.

[0003]

Conventionally, an emulsion of silicone oil or the like has been used for the purpose of preventing the adhesion of the epoxy resin to the lead wires, but the epoxy resin adhesion prevention property, so-called drainage property, is unsatisfactory. Sufficient and no satisfactory effect was obtained. Also, in order to improve the effect, when the concentration of silicone oil is increased and it is attached to the lead wire, a thin film is formed on the lead wire due to the robustness of silicone oil, and because of the high insulating property of silicone oil, There is a drawback in that poor electrical continuity occurs at the connecting portion of the other conducting wire, which causes malfunction of the assembled device.

[0004]

SUMMARY OF THE INVENTION The present inventors have focused on such problems associated with the production of capacitors, and have proposed a method for preventing the epoxy resin from adhering to lead wires during the production of capacitors, an adhesion preventive agent, and As a result of repeated research on an anti-adhesive agent that also functions as a release agent that allows the epoxy resin to be easily released with a fingertip, etc.
It has been found that a homopolymer of 21 polymerizable compounds containing a perfluoroalkyl group or a copolymer with up to 10% by weight of another polymerizable compound is extremely effective as an anti-adhesive agent. .

That is, the gist of the present invention is to have 4 to 2 carbon atoms.
90% by weight of a homopolymer composed of a polymerizable compound containing a perfluoroalkyl group of 1 or a polymerizable compound containing a perfluoroalkyl group of 4 to 21 carbon atoms
Any one of the above copolymers and a copolymer composed of 10% by weight or less of a compound copolymerizable therewith is applied to the lead wire of the capacitor so as to include at least an end,
Next, a method of coating the surface of the capacitor with an epoxy resin is characterized in that a part or the whole of the coated portion of the capacitor body and the lead wire is dipped in the epoxy resin, and finally the epoxy resin is cured.

When the anti-adhesion agent of the present invention is applied to a substrate such as a metal wire, the epoxy resin does not adhere to the substrate, and even if it adheres, it can be easily removed with a fingertip. Further, the base body, for example, the metal wire, does not have any adverse effect on the soldering characteristics even when it is connected to another metal by soldering, etc., and does not cause electrical conduction failure. The polymerizable compound containing a C 4-21 perfluoroalkyl group used in the present invention includes various compounds having a C 4-21 perfluoroalkyl group.

Specifically, for example, the formula:

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[Chemical 3]

[Chemical 4] [Wherein, Rf is a perfluoroalkyl group having 4 to 21 carbon atoms; R is hydrogen or an alkyl group having 1 to 10 carbon atoms; R '
Is an alkylene group having 1 to 10 carbon atoms; R "is hydrogen or a methyl group; R '" is an alkyl group having 1 to 17 carbon atoms;
Represents an integer of 10. ] The compound which has a C4-C21 perfluoroalkyl group in one end, and has a carbon-carbon double bond in the other end as shown by these is mentioned.

There are various compounds which can be copolymerized with the above compounds, and the main ones are (1) acrylic acid, methacrylic acid and their methyl, ethyl, butyl, isobutyl, propyl and 2-ethylhexyl. , Hexyl, decyl, lauryl, stearyl, β-hydroxyethyl, glycidyl esters, (2) acetic acid, propionic acid, caprylic acid, lauric acid, vinyl esters of fatty acids such as stearic acid, (3) styrene, α-methyl Styrene, styrenic compounds such as p-methylstyrene,
(4) Vinyl halides or vinylidene compounds such as vinyl fluoride, vinyl chloride, vinyl bromide, vinylidene fluoride and vinylidene chloride, and (5) allyl esters of fatty acids such as allyl heptanoate, allyl caprylate and allyl caproate. (6) Vinyl alkyl ketones such as vinyl methyl ketone and vinyl ethyl ketone, (7) N-methyl acrylamide, N-methylol methacrylamide, acrylamides such as glycidyl acrylate and glycidyl methacrylate, and (8) 2,3 Examples include dienes such as dichloro-1,3-butadiene and isoprene. Among these, acrylic acid esters, methacrylic acid esters, and styrene compounds are particularly preferable because of ease of copolymerization.

The proportion of the polymerizable compound containing a perfluoroalkyl group and the compound copolymerizable therewith in the polymer is 100 to 90% by weight and the latter is 0 to 90% by weight.
10% by weight is preferred. The anti-adhesion performance is best when a small amount of other copolymerizable compound is present, and the performance decreases as this amount is increased. The method of the polymerization reaction for producing the polymer used in the present invention can be arbitrarily selected, and any of various polymerization methods such as bulk polymerization, solution polymerization, suspension polymerization, emulsion polymerization and radiation polymerization can be adopted.

For example, a mixture of compounds to be copolymerized is dissolved in an appropriate organic solvent, and a solution is produced by the action of a polymerization initiation source (such as a peroxide soluble in the organic solvent used, an azo compound or ionizing radiation). Polymerize. Alternatively, a mixture of compounds to be copolymerized is emulsified in water in the presence of a surfactant, and emulsion-polymerized by the action of a polymerization initiation source such as a peroxide, an azo compound or ionizing radiation. As the surfactant, various anionic, cationic or nonionic surfactants are used.

The anti-adhesive agent of the present invention comprises the polymer used in the present invention in an amount of 0.2 to 3% by weight, preferably 0.5 to 1.5% by weight.
Is dissolved in an organic solvent or is dispersed in water together with a suitable emulsifier to prepare a composition for use.

As a suitable solvent, a fluorinated solvent such as trichlorotrifluoroethane, tetrachlorodifluoroethane or metaxylenehexafluoride is used. As the emulsifier, various anionic, cationic or nonionic emulsifiers can be used, and particularly preferable are emulsifiers cationic and nonionic. Desirable anionic emulsifiers are sodium salts of sulfated alkenyl acetate having 16 to 18 carbon atoms, sodium oleate, sodium salts of sulfated methyl oleate, and 8 to 10 carbon atoms.
Ammonium ω-H-polyfluoroalkanoate,
Ammonium perfluoroalkanoate, carbon number 10
~ 18 alkyl sodium sulfate, carbon number 12
.About.18 sodium alkylbenzene sulfonate, sodium alkylnaphthalene sulfonate, and the like. Further, preferred cationic compounds include (dodecylmethylbenzyl) trimethylammonium chloride, benzyldodecyldimethylammonium chloride, N- [2-
(Diethylamino) ethyl] -oleamide hydrochloride, dodecyltrimethylammonium acetate, trimethyltetradecylammonium chloride, hexadecyltrimethylammonium chloride, trimethyloctadecylammonium chloride and the like. Desirable nonionic emulsifiers also include condensation products of ethylene oxide with hexylphenol, isooctylphenol, hexadecanol, oleic acid, alkanethiols having 12 to 16 carbon atoms, alkylamines having 12 to 18 carbon atoms, and the like.

In order to impart anti-adhesion properties to the substrate, it is sufficient to immerse the substrate, for example the lead wire of a capacitor, in the inhibitor composition and air dry. It is preferable to use a solution type composition as the composition because of the ease of air-drying and the compatibility of the solution. Next, the present invention will be described more specifically by showing Examples and Comparative Examples. In each example, part or%
The term "parts" means "parts by weight" or "% by weight" unless otherwise specified.

Example 1

Embedded image (mixture of n = 3,4,5 compounds in a weight ratio of 4: 2: 1) 32
g, 2-ethylhexyl methacrylate 0.8 g and glycidyl methacrylate 0.8 g were dissolved in a mixed solvent of acetone 23 g, tetrachlorodifluoroethane 128 g, and trichlorotrifluoroethane 50 g, and the mixture was put into a 300 ml four-necked flask, and the internal air was replaced with nitrogen. After substituting with gas, a solution of 3 g of t-butylperoxypivalate in 70% paraffin is added dropwise and a polymerization reaction is carried out at 55 ° C. for 7 hours.
Then a solution of 3 g of t-butyl peroxypivalate is added dropwise and the polymerization is continued at the same temperature for 7 hours. By this polymerization reaction, 230 g of a solution containing 14.2% of the polymer was obtained.

Example 2

[Chemical 6] 30g, emulsifier (dimethyloctadecylamine / acetate)
1.5 g, 15 g of acetone and 165 g of water are added to 300 ml of 4
The flask is placed in a two-necked flask, the air inside is replaced with nitrogen gas with stirring, and the mixture is heated on a water bath. When the internal temperature reached 55 ° C, a solution of 0.2 g of azobisisobutyroamidine hydrochloride in 10 g of water was added dropwise, the internal temperature was kept at 60 ° C, and the polymerization reaction was continued for 2 hours.

[Chemical 7] 210 g of an emulsion dispersion containing 14% of the homopolymer of was obtained.
The polymers used in the following Examples 3 to 8 are those obtained in Example 1 or 2, or those produced by the same procedure as in Examples 1 and 2.

Examples 3 to 8 and Comparative Examples 1 to 5 A portion of 7 cm of the lead wire for a capacitor, 2 cm from the end, was dipped in each anti-adhesive composition shown in Table 1 until the solvent or water disappeared at room temperature. dry. 5 cm from the end of the lead wire coated with the anti-adhesive agent is dipped in the epoxy resin composition for capacitors, pulled up, allowed to stand at room temperature for 10 minutes, and then cured at 120 ° C. for 1 hour in a constant temperature bath.
The surface of each lead wire coated with the anti-adhesion agent thus treated was observed, and whether or not the epoxy resin adhered to the surface was visually determined according to the following criteria. The results are shown in Table 1.

Judgment Criteria ⊚ No epoxy resin adheres to the part coated with the anti-adhesion agent. ○ A small amount of epoxy resin adheres to the area where the anti-adhesive agent is applied, but it can be removed immediately by touching it with your fingertips. △ Epoxy resin is mottled on the part coated with the anti-adhesive agent and can be removed easily with a fingertip. × There is no effect of the anti-adhesion agent, and the epoxy resin adheres as in the uncoated area.

[0018]

[Table 1]

Claims (1)

[Claims] 1. A homopolymer composed of a polymerizable compound containing a C4-21 perfluoroalkyl group or 90% by weight or more of a polymerizable compound containing a C4-21 perfluoroalkyl group, and Any one of the copolymers composed of 10% by weight or less of a copolymerizable compound was applied to the lead wire of the capacitor so as to include at least the ends, and then the capacitor body and the lead wire were applied. A method for coating a capacitor surface with an epoxy resin, which comprises immersing a part or all of a portion in an epoxy resin and finally curing the epoxy resin.