JPH0630320B2 - Metallized film capacitor - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION (Industrial field of application) The present invention relates to a metallized plastic film capacitor comprising a capacitor element formed by winding a metallized plastic film, which is formed by filling epoxy resin and curing it, a so-called semi-dry type. Of metallized film capacitors of.

(Prior art and its problems) A metallized film capacitor (hereinafter referred to as MF capacitor) formed by winding a metallized film has a self healing action, so that it is easy to increase the withstand voltage. It is widely used because it can be downsized.

By the way, the so-called dry type MF capacitors which do not impregnate an electrically insulating impregnating agent such as an electrically insulating oil are mainly used as the MF capacitors which have been put into practical use at present.

Generally, not only capacitors but also various electric devices have a higher potential gradient when an electrically insulating impregnating agent is present in the environment around electrodes or conductors. That is, the withstand voltage is improved, which is advantageous. Further, at this time, if an impregnating agent having appropriate electric characteristics is selected, higher voltage can be achieved.

Therefore, the impregnated MF capacitor is preferable to the dry one, but the metal vapor-deposited film having a polypropylene film as a base film changes its film size when impregnated with an electrically insulating impregnating agent, Further, the impregnating agent may penetrate into the layer between the vapor-deposited metal layer and the base film that are physically adhered to each other to cause cracks in the metal layer, and in extreme cases, the metal layer may peel off and cause dielectric breakdown. It may reach.

Therefore, as an improvement of the dry MF capacitor, the MF capacitor utilizes the characteristic that dielectric breakdown often occurs at the end face and the outer peripheral portion of the wound capacitor element,
A certain degree of improvement has been achieved by making a semi-dry MF capacitor in which only the end face and the outer peripheral part are impregnated with an impregnating agent and the inside is not impregnated.

However, the semi-dry type is partially impregnated, and since the periphery of the essential electrode layer is not impregnated, its performance improvement is limited, and it is unsatisfactory as compared with the impregnated MF capacitor. There is no denying it.

The insulating agent used for the above-mentioned semi-dry MF capacitor is
Epoxy resins have been used conventionally.

However, since the epoxy resin is expensive, various inexpensive extenders such as petroleum resin and wax are mixed, but the electrical characteristics, especially the performance as a capacitor may be deteriorated, and its improvement has been desired. .

(Means for Solving Problems) The present invention has been completed by discovering that if a petroleum resin according to a specific production method is mixed with an epoxy resin and used, it can be used without deterioration in performance as a capacitor. Is.

That is, the present invention is a capacitor consisting of a capacitor element containing at least a part of a metallized plastic film, unsaturated per 100 parts by weight of epoxy resin, which is a by-product of thermal decomposition of petroleum in the boiling range of 80 ~ 280 ℃. An epoxy resin composition containing 5 to 900 parts by weight of a resin obtained by adding 7 to 45 parts by weight of a phenol to 100 parts by weight of a hydrocarbon fraction containing hydrocarbon as a main component and polymerizing with a Friedel-Crafts type catalyst is filled. And to a cured metallized film capacitor.

The present invention will be further described below.

The main raw material of the resin used in the composition of the present invention is naphtha, distillate through light, or petroleum such as butane, which is a by-product when producing olefins such as ethylene and propylene by thermal decomposition such as steam cracking. It is a cracked oil fraction in the boiling range of 280 ° C. to 280 ° C., each distillate fraction distilled in the boiling point range, or each of these distillate fractions is appropriately prepared. Aromatic olefins having 8 to 10 carbon atoms such as styrene and alkylstyrene, indene and alkylindene are present in a large amount in the cracked oil fraction having a boiling point of 80 to 280 ° C., for example, 35 to 65% by weight. A cracked oil fraction having a boiling point of less than 80 ° C. is not preferable because the resin obtained therefrom has poor compatibility with the epoxy resin. However, within the range in which the effect of the present invention is achieved, a cracked oil fraction having a boiling point of less than 80 ° C., for example, 20 to 80 ° C. is used in the present invention by mixing a small amount such as 20% by weight or less. It can also be used as a hydrocarbon fraction and polymerized.

Next, the phenols to be added to the above hydrocarbon fraction are phenol and alkyl-substituted phenols such as cresol, xylenol, tert-butylphenol, nonylphenol and the like, or a mixture of two or more thereof.

To 100 parts by weight of the above hydrocarbon fraction, 7 to 45 phenols are added.
Mix by weight and polymerize with a Friedel-Crafts type catalyst.
When the amount of the phenols is less than 7 parts by weight, the obtained resin has poor compatibility with the epoxy resin, and the performance of the capacitor also deteriorates. Further, if it exceeds 45 parts by weight, not only a resin having an extremely bad hue is obtained but also it is uneconomical, which is not preferable.

Polymerization was performed by adding a Friedel-Crafts type catalyst such as boron trifluoride, aluminum chloride, a boron trifluoride phenol complex, a boron trifluoride dialkyl ether complex to the raw material in an amount of 0.05 to 5% by weight, and at -10 to + 80 ° C. In the temperature range of
Do 10 minutes to 15 hours. After polymerization, the catalyst is decomposed and removed with an alkali such as caustic soda or sodium carbonate, washed with water if necessary, and the unreacted oil and low molecular weight polymer are separated by evaporation or distillation to obtain a pale yellow or yellow resin. . The resin obtained has a softening point (according to JIS K 2531-60) of 50 to 120 ° C. and a number average molecular weight of 500 to 1500.

The resin used in the present invention obtained as described above is IR
According to the spectrum, it is recognized that a large amount of phenolic hydroxyl groups is contained, which is clearly different from the conventional petroleum resin.

The epoxy resin referred to in the present invention is a known epoxy resin that has been conventionally used in a semi-dry MF capacitor.
Those having a molecular weight of 300 to 3000 and an epoxy equivalent of 150 to 3500 are usefully used.

A typical epoxy resin is obtained as a reaction product of a compound having active hydrogen and epichlorohydrin. Examples of the compound having active hydrogen include compounds having two or more phenolic OHs in the molecule, for example, bisphenol A, novolac resin and derivatives thereof, and also compounds having a carboxyl group, an amino group, etc. Good. Particularly in the present invention, the epoxy resin obtained by the reaction of bisphenol A and epichlorohydrin can be advantageously used.

In the present invention, the mixing ratio of the resin and the epoxy resin is 5 to 900 parts by weight of the resin per 100 parts by weight of the epoxy resin. If the amount of the above resin exceeds 900 parts by weight, the curing of the epoxy resin will be insufficient and the original properties of the epoxy resin will be lost, which is not preferable, and if less than 5 parts by weight, the effect of adding the resin will not occur.

Furthermore, the epoxy resin composition of the present invention comprises 5 to 100 parts by weight, preferably 30 to 50 parts by weight, of a known curing agent for curing the epoxy resin per 100 parts by weight of the epoxy resin. Known curing agents include diethylenetriamine, triethylenetetramine, aliphatic amines such as adducts of epoxy resins and aliphatic amines, aromatic amines such as metaphenylenediamine, diaminodiphenylmethane, diaminophenylsulfone, and methyl nadic anhydride. In addition to acid anhydrides such as hexahydroanhydride, urea resins, melamine resins, phenol resins, polyisocyanates and the like can be mentioned.

Further, an inorganic filler such as mica, silica, calcium carbonate, or talc can be mixed in an arbitrary ratio in order to improve the thixotropic property of the epoxy resin composition. Other known flame retardants for epoxy resins, for example, tetrabromobisphenol A, decabrom diphenyl ether, halogenated flame retardants such as chlorinated paraffin, ammonium phosphate, tricresyl phosphate, triethyl phosphate, tris (β-chloroethyl) Phosphorus flame retardants such as phosphates, acidic phosphates, nitrogen-containing phosphorus compounds, etc., inorganic flame retardants such as red phosphorus, tin oxide, ammonium trioxide, zirconium hydroxide, barium metaborate, aluminum hydroxide, magnesium hydroxide, etc. Can also be used. In addition, monoepoxides such as styrene oxide and olefin oxide, reactive diluents such as polyepoxide such as divinylbenzene dioxide, and non-reactive diluents such as dioctyl phthalate can also be used to reduce the viscosity of the epoxy resin composition. Used for other reasons to improve sex.

In the present invention, a metallized film capacitor is obtained by filling the above epoxy resin composition in an appropriate case containing a capacitor element and heating and curing.

Here, the capacitor element is an element formed by winding a plastic film having one or both sides metallized with a metal such as aluminum or zinc. As the plastic film, a polyolefin film such as polypropylene or a polyester film such as polyethylene terephthalate is used. When winding,
Insulating paper or plastic film may be laminated and wound together with the metallized film. An element formed by winding is usually subjected to a metallikon treatment on its end face and a lead wire is attached thereto.

When the capacitor has a case as an exterior, the epoxy resin composition is filled with the epoxy resin in the case accommodating the capacitor element and then cured. In the case of a capacitor having no exterior, the capacitor element is housed in a case as a container or mold of epoxy resin, and the epoxy resin is filled or cast and cured. In this case, the case is removed after curing. After the epoxy resin is filled, the capacitor element may be housed in a case and cured.

The curing of the epoxy resin composition is carried out so as not to adversely affect the plastic film in the device, but a heating temperature of 70 to 100 ° C. and a heating time of 1 to 5 hours are usually sufficient.

(Effect of the Invention) By mixing an inexpensive resin according to a specific production method, the amount of an expensive epoxy resin used is reduced, but an MF capacitor having improved performance as a capacitor can be obtained.

(Examples) Hereinafter, the present invention will be specifically described based on resin preparation examples, examples and comparative examples. The compounding values in Tables 1 and 2 are all parts by weight.

Resin Preparation Example 1 18 parts by weight of phenol was added to 100 parts by weight of a hydrocarbon fraction having a boiling range of 140 to 210 ° C. and a unsaturated fraction of 57% by weight in a cracked oil fraction obtained from steam cracking of naphtha. 0.7 parts by weight of boron trifluoride ethyl ether complex was added, and the mixture was polymerized at 60 ° C. for 3 hours. After the polymerization, the catalyst was decomposed with an aqueous caustic soda solution, washed with water, and unreacted oil was removed by distillation under reduced pressure to obtain a resin (I) having a softening point of 95 ° C. Resin yield is 58
% By weight.

Resin Preparation Example 2 Polymerization was carried out in the same manner as in Resin Preparation Example 1 except that 100 parts by weight of the hydrocarbon fraction used in Resin Preparation Example 1 plus 2 parts by weight of phenol was used as a raw material, and a resin having a softening point of 110 ° C. (II) was obtained. The resin yield was 50% by weight.

Resin Preparation Example 3 A resin having a softening point of 83 ° C. was polymerized in the same manner as in Resin Preparation Example 1 except that 25 parts by weight of phenol was added to 100 parts by weight of the hydrocarbon fraction used in Resin Preparation Example 1 as a raw material. (III) was obtained. The resin yield was 62% by weight.

Resin Preparation Example 4 The hydrocarbon fraction used in Resin Preparation Example 1 was fractionated by precision distillation into a fraction having a boiling point of 176 to 190 ° C. The unsaturated component in this fraction was 58% by weight, and the indene content was 37% by weight. 25 parts by weight of nonylphenol was added to 100 parts by weight of this fraction, and 0.7 parts of boron trifluoride phenol complex compound catalyst was added.
Resin preparation example 1 after adding wt% and polymerizing at 40 ° C. for 3 hours
A resin (IV) was obtained by the same treatment as described above. The resin yield was 58% by weight and the softening point was 97 ° C.

Examples 1 and 2 and Comparative Examples 1 and 2 A biaxially oriented polypropylene film having a thickness of 15 µm was vapor-deposited with aluminum on one side according to a conventional method to obtain a metallized plastic film having a width of 40 mm and a margin of 3 mm. The capacitor element made by winding this is stored in the case,
A model capacitor was made. Next, the epoxy resin having the composition shown in Table 1 and the epoxy resin composition containing the resin (I) obtained in Resin Preparation Example 1 were filled in each to obtain a capacitor having a capacity of about 5 μF (Example 1 ~
2).

Then, it heated at 90 degreeC for 3 hours, and hardened the epoxy resin. After curing, a constant voltage was applied to the capacitor, and the performance of the capacitor was examined by measuring the time change of the capacity. The results are shown in Fig. 1.

For comparison, an MF capacitor filled with only an epoxy resin (Comparative Example 1), an epoxy resin and a resin preparation example 2
The performance of the capacitor was also tested for the MF capacitor (Comparative Example 2) filled with the epoxy resin composition containing the resin (II) obtained in 1.

From the results shown in FIG. 1, it can be seen that the MF capacitors of Examples 1 and 2 are excellent capacitors with a small change in capacitance over time as compared with the MF capacitors of Comparative Examples 1 and 2.

Examples 3 to 7 Epoxy resin having the composition shown in Table 2 and Resin Preparation Example 1,
Using the epoxy resin composition containing each of the resins (I), (III) and (IV) obtained in 3 to 4, a model capacitor was filled in the same manner as in Example 1 and cured, and then the capacity was increased. The time change rate of was calculated. As a result, each of them was almost the same as the capacitor of Example 1, and its performance was satisfactory.

[Brief description of drawings]

FIG. 1 is a graph showing the relationship between the capacitance changes of the capacitors of Examples 1 and 2 and Comparative Examples 1 and 2 and time.

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁵ Identification code Office reference number FI technical display location (C08L 63/00 57:02) 7242-4J

Claims (2)

[Claims] 1. A metallized plastic film capacitor comprising a capacitor element containing a metallized plastic film in at least a part thereof, wherein per 100 parts by weight of epoxy resin, a boiling point range of 80 to 280 ° C., which is a by-product of thermal decomposition of petroleum, is obtained. Hydrocarbon fraction containing an unsaturated hydrocarbon as the main component 10
Resins obtained by adding 7 to 45 parts by weight of phenols to 0 parts by weight and polymerizing with a Friedel-Crafts catalyst
A metallized film capacitor obtained by filling and curing an epoxy resin composition containing 1 part by weight. 2. The metallized film capacitor according to claim 1, wherein the epoxy resin composition further contains a curing agent in an amount of 5 to 100 parts by weight per 100 parts by weight of the epoxy resin.