JPS62165905A - Manufacture of across-the-line capacitor - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION 0) OBJECTS OF THE INVENTION The present invention relates to a method of manufacturing an across-the-line capacitor.

(Industrial Application Field) The method for manufacturing an across-de-line capacitor of the present invention can easily manufacture a capacitor that has excellent explosion resistance and moisture resistance, and is small compared to its capacity, using a simple work process. It can be used advantageously to

(Prior art) For noise prevention used in AC Kr, +11 power supply circuits,
Insulating capacitors are required to have a high level of safety, as overcurrent during electric shock or lightning strikes can cause dielectric breakdown, leading to element explosions and fires. For example, safety is strictly regulated by the UL standard in the United States and the C8A standard in Canada.

That is, for example, the UL standard requires across-the-line capacitors (capacitors connected across power supply poles) to satisfy the following four tests.

(a) Exterior flame retardancy test (flame contact test) (b) Discharge test (ignitability test) (e) Discharge test (explosion resistance test) (d) Life test (left at 80°C for 1000 hours) When a high voltage is applied to a capacitor, dielectric breakdown occurs instantaneously, and the gas generated by the heat generated by the short circuit destroys the exterior, and the explosion resistance test (c) above is a test related to this. 〇In order to pass the tests (b) and (e) above, it is necessary that the coating film is not destroyed during the test, and for this purpose, the following three types of manufacturing methods have traditionally been used to manufacture such film capacitors. was used.

(1) Case method In this method, in order to suppress the shock of an explosion, the entire device is placed in a case made of noryl resin or polybutylene terephthalate resin, and then a thermosetting resin such as epoxy resin is injected and heated to harden the case. This is the potting method used.

(11) Molding method This is a molding method in which an element is placed in a mold, a highly elastic resin such as urethane rubber is injected, and after curing by heating, the mold is removed to produce a product.

(iii) Method for improving the internal structure of the element This is a method in which one element has a structure in which two capacitors are connected in series, and the element is dip-coated with a thermosetting paint such as epoxy resin. Capacitors manufactured using this method cause less shock to the exterior because the explosion occurs at the connections between the capacitors inside the element.

However, these conventional methods have the following drawbacks.

Both the case method and the mold method require multiple work steps. In other words, in the case of the case method, there are four steps: fixing the jig to the case, fully injecting the epoxy resin into the case, loading the device into the case, fixing the case and the device, and heating the epoxy resin. It requires the steps of curing and removing the device from the jig in which it is fixed.

In addition, in the case of the molding method, there are a process of applying a mold release agent inside the mold, a process of fixing the mold to a jig, a process of injecting urethane polymer into the mold, and a process of inserting the element into the mold. process, fixing the element to the mold, heating to harden the urethane polymer, removing the element from the jig together with the mold, removing the element from the mold, removing paris attached to the element , and cleaning the mold.

Furthermore, the case method and the mold method require long-time heating to cure the epoxy resin or urethane resin used, and have the disadvantage that the working time is long. For example, in the case of epoxy resin, it is necessary to heat it at a temperature of 100°C or more for more than 2 hours, and in the case of urethane polymer, it is necessary to heat it for more than 2 hours.
Requires heating for more than an hour.

In the case method and mold method, since the case or cast product is usually a rectangular parallelepiped, the volume is larger than that of a rounded capacitor, and it is unavoidable that the capacitor is larger than a dip-type capacitor.

In addition, the capacitor obtained by the above-mentioned method of improving the internal structure of the element does not have the drawbacks of the case method or mold method, but
However, since the two capacitors are connected in series, the capacitor obtained by this method has a total capacitance of 1/2 of each capacitance, which is twice the capacitance of the case method or mold method. You have to connect two of them. Therefore, the amount of film is doubled, which is not only uneconomical, but also unavoidably larger than the capacity.

On the other hand, a polymerizable curable resin composition containing a prepolymer having a carbon-carbon double bond that can be cured by ultraviolet rays and heating, a monomer having an ethylenic double bond, a photopolymerization initiation MIJ, and a thermal polymerization initiator. A method is already known in which electrical parts are coated with a material and the coating film is cured by radiation and heat; however, with such a coating method,
For example, film capacitors with excellent explosion resistance that pass UL standards, especially across de line capacitors.
There was no known method for manufacturing zoshita.

The present inventors previously proposed a method for easily manufacturing film capacitors, particularly 7 cross-the-line capacitors, and 9 capacitors, by coating them with a radiation-polymerizable composition and using a simple process. No. 59-206138).

The method includes forming a film capacitor using a polymerizable composition containing a prepolymer having a polymerizable carbon-carbon double bond, a monomer having an ethylenic double bond, and a copolymerization initiator and/or a thermal polymerization initiator. In a method of coating and curing the coating film by radiation and/or heating,
The numerical value (absolute value) of the elongation rate (%) at 25℃ of the cured coating film and the tensile strength ()C9/m'' at 25℃
) is a method of controlling the value (absolute value) of is being manufactured, and its capacitor has a capacitance of 5
UL standard 1414 for a 00nF capacitor
However, as the capacitance of the capacitor becomes even stronger, the explosion energy also increases, so a higher level of explosion resistance is required, and the method of the patent application was not successful. However, it is not possible to respond adequately. In addition to explosion resistance, across-the-line capacitors have other electrical properties that vary depending on the type of equipment to which they are installed or the location where they are installed, particularly moisture resistance, that is, a decrease in internal insulation resistance due to moisture absorption. Characteristics such as a small capacitance and a small rate of change in capacitance are required, but the method of the patent application cannot meet these requirements.

(Problems to be Solved by the Invention) The present invention provides a method for easily manufacturing an across-de-line capacitor that has excellent explosion resistance and moisture resistance using relatively simple painting. This is what we are trying to provide.

(B) Structure of the Invention As a result of repeated research in order to solve the above-mentioned problems, the present inventors discovered a radically polymerizable resin containing a specific prepolymer, a photopolymerization initiator, and a thermal polymerization initiator. The coating is coated with an undercoat containing an epoxy resin containing an imidazole curing agent, the coating film is cured by ultraviolet irradiation, and the coating film is further coated with a photopolymerization initiator and a thermal polymerization initiator. A top coat using urethane polymer is applied, the coat is irradiated with ultraviolet rays, and then both films are completely cured by heating, and the physical properties of the cured top coat are controlled to specific values. In other words, in the method for manufacturing an across-the-line capacitor of the present invention, first, epoxy (meth)acrylate, ethylene, and double bond 'f,
A radically polymerizable resin containing a monomer, a photopolymerization initiator, and a thermal polymerization initiator is mixed with an epoxy resin containing an imidazole curing agent. After applying an undercoat paint, the coating film is cured by ultraviolet irradiation, Next, on the coating film, a urethane polymer having a terminal (meth)acryloyl group and a number average molecular weight in the range of 2,000 to 20,000, a monomer having an ethylenic double bond, a photopolymerization initiator, and a thermal polymerization initiator are added. After applying a topcoat, the coating film is cured by UV irradiation, and both coatings are completely cured by heating, and the elongation rate (%) of the cured coating of the topcoat at 25 ° C. (Absolute value)
The product of the numerical value (absolute value) of the tensile strength (kg/W2) and the tensile strength (kg/W2) is 1
This method is characterized by controlling to 00 or more.

What is "(meth)acrylic acid" described in this specification?

It is a generic term for acrylic acid and methacrylic acid, "(meth)acrylate" is a generic term for acrylate and methacrylate, and "(meth)acryloyl group" is a generic term for acryloyl group and methacryloyl group.

Various epoxy (meth)acrylates can be used in the undercoat of the present invention.

Examples include bisphenol (such as bisphenol A) type epoxy resin, epoxy resin type epoxy resin, and epoxy resin obtained by reacting an alicyclic epoxy resin with (meth)acrylic acid. Epoxy (meth)acrylate has a large effect on the curing speed and physical properties of coating films. Using epoxy (meth)acrylate, other pre-j? The moisture resistance of the canopy is improved compared to when IJ Mama is used.

In addition to participating in the polymerization curing reaction as a crosslinking agent, the monomer having an ethylenic double bond in the primer coating of the present invention acts as a diluent for epoxy (meth)acrylate, and also acts as a diluent for epoxy (meth)acrylate. Styrenic compounds such as styrene; esters of (meth)acrylic acid and alcohols, such as 2- and droxyethyl (meth)acrylate, carpitol (meth)acrylate, trimethylolpropane tri(meth)acrylate
), 1,6-hexanediol (meth)acrylate, etc.; diallyl phthalate, triallyl isocyanurate, etc. allyl groups'! Examples include compounds that These compounds may be used alone or in combination of two or more.

The photopolymerization initiator and L-ite for the undercoat paint of the present invention.

Examples include benzine, benzoin ethyl ether, benzophenone, benzyl dimethyl ketal, hydroxycyclohexylphenyl ketone, 2-ethylanthraquinone, etc., and these can be used alone or in combination of two or more. .

The usage ratio of the photopolymerization initiator is 0.0% relative to the total amount of epoxy (meth)acrylate and ethylenically unsaturated compound.
It is about 5 to 5% by weight.

As a thermal polymerization initiator for the undercoating paint of the present invention.

For example, methyl ethyl ketone monooxide, benzoyl peroxide, t-butyl! -oxybenzony), 1,1-not-t-butylperoxy-3,3,5
-trimethylcyclohexane, etc., and these can be used singly or in combination of two or more. The ratio of thermal polymerization initiator used is epoxy (meth)
The amount is approximately 0.5 to 5% by weight based on the total amount of the acrylate and the monomer having an ethylenic double bond.

The epoxy resin for the undercoat paint of the present invention contributes to improving the moisture resistance and insulation properties of the cured coating film. Various epoxy resins can be used, but one representative example is bisphenol type ( Particular examples include bisphenol A type epoxy resins and novolac type epoxy resins.

In the present invention, an imidazole curing agent is selectively used as the curing agent for the epoxy resin for the undercoat.

This is because when other hardeners, such as acid anhydride hardeners, are used, they react with the hydroxyl groups of epoxy (meth)acrylates and significantly shorten the pot life of the paint, but imidazole hardeners This is because there is less risk of shortening the usable life of the paint, and the usable life of the formulation is longer. Examples of the imidazole-based fecalizing agent used include 2-nityl-4-methyl imitazole, 1
-Benzyl-2-methylimidazole, 1-cyanoethyl-2-ethyl-4-methylimidazole, 1-isobutyl-2-methylimidazole and the like which have good compatibility with the epoxy resin are used. In particular, 1-cyanoethyl-2-ethyl-4-methylimidazole is preferred because it can extend the usable life of the paint the longest. The amount of curing agent added is 2 to 10% by weight based on the epoxy resin.

The mixing ratio of the radically polymerizable resin and the curing agent-containing epoxy resin in the undercoat of the present invention is 1:9 to 9:1,
Preferably, the ratio τ1 is between 2:8 and 8:2, and both are mixed uniformly. If the proportion of epoxy resin is too high, the ultraviolet curing speed will be slow, and sagging will occur during heat curing.
The thickness of the cured coating film will be uneven, and if the gap is too small, radical polymerization will be inhibited by oxygen in the air during ultraviolet irradiation.

Moisture resistance of the cured coating film deteriorates.

The urethane polymer having a terminal (meth)acryloyl group and having a number average molecular weight of 2,000 to 20,000 in the top coating of the present invention is, for example, a reaction product of a polyester and a polyvalent isocyanate compound or a polyhydric alcohol and a polyurethane polymer. Typical examples include urethane polymers obtained by addition-reacting (meth)acrylic acid to a reaction product with an incyanate compound, and having a number average molecular weight within the above range. If the number average molecular weight is less than 2,000, the elongation rate of the cured coating film will be small, and the explosion resistance of the obtained canon 4-shita will be reduced. Also, if it is larger than 20000.

Workability deteriorates due to increased viscosity of the prepolymer.

In that case, if an attempt is made to lower the viscosity by adding a diluent, a considerable amount of diluent is required, and the diluent has a negative effect on the physical properties of the cured coating film.〇The top coat of the present invention The monomer having an ethylenic double bond for the undercoat is the same as the monomer having an ethylenic double bond for the undercoat. ) The same substances as those used in paints are used, and the amounts used are similar to those used in base coat paints.The base coat paint and top coat paint of the present invention may contain various additives, such as pigments, pigments, etc., as necessary. Flame retardants, fillers, thixotropic agents, tack-free agents, etc. can be added.

Examples of flame retardants include hexabromobenzene,
Halogen-containing compounds such as chlorinated polyethylene, 9-chlorocyclodecane, tetrabrom diphenyl ether, hexabrom diphenyl ether, and tetrabrom phenyl (meth)acrylate; Phosphorus or its compounds such as trimethyl phosphate and red phosphorus; antimony trioxide, aluminum oxide Inorganic flame retardants such as especially,
Tetrabromidiphenyl ether (including its crude products) is preferable because it not only has a flame retardant effect but also improves the flexibility, electrical properties, and ultraviolet curability of the cured coating film◇ Its filler or thixotropic agent For example, fine powder silica such as kaolin clay, alumina, mica, and Airosil (trade name of Nippon Airosil Co., Ltd.).

Organic bentonite derivatives, Merck, asbestos.

Examples include calcium carbonate.

Examples of the pigment include titanium oxide, red iron oxide, and phthalocyanine blue, and examples of the tack-free agent include those containing allyl ether foundation and those having a urethane bond in the main chain. When a tack-free agent having a urethane bond in the main chain (for example, Nippon Gohsei Kagaku Kogyo Co., Ltd.'s product name Goselac UV-10) is used, the surface hardening properties of the cured coating film are improved, and at the same time, the tack-free agent has a urethane bond in the main chain. Prevents surface burns and wrinkles.

Various methods can be used to apply the undercoat and topcoat in the present invention. For example, methods such as dip method, spray method, and brush coating method are used.The thickness of the coating film is 0.1 to 0.5 mm for the undercoat and 0.5 for the topcoat as the thickness of the cured coating. is 0.5 to 2 gourds.

In addition, the curing conditions in the present invention are that the UV irradiation is for 30 seconds or less for both the undercoat and the topcoat, and the heating is for 10 seconds or less.
The temperature is 0 to 130°C for about 30 to 120 minutes.

(Examples, etc.) Below, coating preparation examples, examples, and comparative examples are given and described in detail. The parts stated in these examples are parts by weight.

Undercoat paint preparation example A.

An undercoat paint having the composition ratio shown below was prepared.

This undercoat paint is called undercoat paint A.

Composition of primer paint A: Kayarad R-011" 70 parts styrene 30 parts 2-ethylanthraquino 7 1 part t-butyl peroxybenzoate 2 parts Epicor) 828"
100 parts asbestos powder 3 parts *2.
...Product name of epoxy resin manufactured by Yuka Shell Co., Ltd. Top coat preparation example B.

A top coat having the composition ratio shown below was prepared.

This top coat is called top coat B.

Composition of topcoat B1 (diurethane acrylate) *s 20 parts 2-hydroxypropyl acrylate 15 parts 2-hydroxypropyl methacrylate 5 parts benzyl dimethyl ketal 1.5 parts female combustion agent *4
3 parts aluminum hydroxide 20
Part Asst Rst powder 0.5 part t-Butylperoxybenzoate 1 part Tack-free agent 15 10 parts Umbrella...Daikogyo Seiyaku Co., Ltd. trade name Virogard 5R-900 Umbrella 5...1 bottle Synthetic Kagaku Kogyo Co., Ltd. Trade name: Goselac UV-Top Coat Preparation Example B2 A top coat having the composition ratio shown below was prepared.

This top coat is called top coat B2.

Composition of top coating B2: Urethane acrylate 86 20 parts 2-hydroxypropyl acrylate 15 parts 2-hydroxypropyl methacrylate 5 parts benzyl dimethyl ketal 1.5 parts Flame retardant "4"
30 parts aluminum hydroxide 20 parts phthalocyanine blue 003 parts magnesium titanate o, s parts American 4-stroke powder
0.5 parts 1.1--)-t-butyl/g-oxy-3.3.5-trimethylcyclohexane 1 part tack-free agent 95
10 cities 4. *5...Same as above.

Example 1 A film capacitor made of J-lyethylene terephthalate having a capacity of 1 μF was dipped in undercoating paint A under a reduced pressure of 300 mHg to impregnate the inside of the element with the paint, then pulled out and cured by ultraviolet irradiation. The ultraviolet irradiation conditions were as follows: A metal halide lamp with an output of 80 W/cm was used.
The device was placed on a conveyor moving at a speed of 60 cn/min so that the shortest distance from the lamp to the top of the device was 10 m, and the device was irradiated while moving at the same speed.

The thickness of the undercoat (cured coating) was 0.3 m.

Next, the element with this surface-hardened undercoat film is ≠
It was coated by dipping it into the above-mentioned top coat B1 under normal pressure, and the surface was cured by irradiating ultraviolet rays under the same conditions as for the base coat A1, and then heated at a temperature of 120°C for 30 minutes. Both the undercoat and topcoat were completely cured. The thickness of the top cured coating was approximately In+m.

For the obtained across de capacitor, the elements were
1 mt humidity test to determine the capacity change when left in a desiccator at 0°C and 95% relative humidity for 1000 hours, and U
The explosion resistance test sound of (C) above was carried out based on L Inkstone. The results were as shown in Table 1.

Separately, the top coatings B1 and B2 were coated on a glass plate so that the thickness of the cured coating film was 11, and each coating film was cured under the ultraviolet irradiation conditions for the coating film of Example 1. And after curing under the same curing conditions as the heat curing conditions,
The cured film was peeled off from the glass, and the elongation and tensile strength at 25° C. of each obtained cured film were measured. The results are shown in Table 1.

Example 2 Top coat B2 was used in place of top coat B1 in Example 1, and the coating was otherwise applied in the same manner as in Example 1, cured in the same manner, and various tests were conducted in the same manner.

The results were as shown in Table 1. Comparative Examples 1 to 2 The same film coating as used in Example 1 was applied to the top coat B1 (in the case of Comparative Example 1) or the top coat B2. (In the case of Comparative Example 2) The element was dipped under a reduced pressure of 300 rmnHg to impregnate the inside of the element with the paint, then pulled out, and the entire coating film was irradiated with ultraviolet rays under the same conditions as in the case of Example 1 to cure it. Ta.

The thickness of the cured coating was about 1 inch. The coating film was then further cured by heating at a temperature of 120° C. for 30 minutes.

Got Kiya! The results of a test similar to that in Example 1 are shown in Table 1 (as shown in Table 1). Excellent performance.

(C) Effects of the Invention According to the present invention, an across-the-line capacitor with extremely excellent explosion resistance and moisture resistance can be easily manufactured.

Claims (1)

[Claims] 1) For a film capacitor, first add epoxy (meth)acrylate, a monomer having an ethylenic double bond, a radically polymerizable resin containing a photopolymerization initiator and a thermal polymerization initiator, and an epoxy resin containing an imidazole curing agent. After applying an undercoat containing a compound of
After applying a top coat containing a urethane polymer in the range of 20,000, a monomer having an ethylenic double bond, a photopolymerization initiator, and a thermal polymerization initiator, the coating film is cured by ultraviolet irradiation, and then both are cured by heating. The coating film is completely cured, and the numerical value (absolute value) of the elongation rate (%) at 25°C and the tensile strength (kg/
A method for manufacturing an across-the-line capacitor, characterized in that the product of numerical values (absolute values) of mm^2) is controlled to be 100 or more.