WO2020053747A1

WO2020053747A1 - Insulating film for bus bar and bus bar

Info

Publication number: WO2020053747A1
Application number: PCT/IB2019/057601
Authority: WO
Inventors: 武井邦浩; 飯塚宏和
Original assignee: 藤森工業株式会社
Priority date: 2018-09-13
Filing date: 2019-09-10
Publication date: 2020-03-19
Also published as: JP2020043031A; JP7154905B2

Abstract

The present invention provides: a bus bar insulating film that is adhered through brief heating and exerts excellent adhesive power with respect to metal; and a bus bar equipped with such a film. More specifically, the present invention pertains to: a bus bar insulating film that is to be bonded to the surface of a bus bar and that is characterized by having a base material layer and an adhesive layer, wherein the base material layer contains a resin as a formation material, the adhesive layer contains a phenolic resin (A), and, in a voltage tolerance test, the film is confirmed not to allow current to pass therethrough even at an average field intensity of 5 kV/mm; and a bus bar equipped with such an insulating film.

Description

Busbar insulating film and busbar

The present invention relates to an insulating film for a bus bar and a bus bar.

The bus bar is a component used for an operation panel, a switchboard, a battery, and the like, and is a conductor for conducting a large amount of current. Busbars are mainly made of metals such as copper and aluminum.
Recently, a laminated bus bar in which an insulating film and a metal conductor are laminated and laminated has been put to practical use. An insulating film used for a laminated bus bar is required to have a high adhesive strength to metal. The insulating film generally includes an insulating base layer made of a resin or the like as a constituent material, and an adhesive layer.

In order to adhere the insulating film to the metal conductor, the adhesive layer is made of an adhesive material exhibiting high adhesive strength to metal. Conventionally, a hot-melt adhesive has been used as a material for bonding to an adherend such as a metal. Patent Literature 1 describes a film-like adhesive for connecting circuit members, which includes a thermoplastic resin, an epoxy resin, a phenol resin, and an insulating spherical inorganic filler.

Japanese Patent No. 3,991,268

Bus bars may be used in high temperature environments. For this reason, the insulating film for bus bars is required to have an adhesive force that does not peel even under a high-temperature environment. Further, it is preferable that the insulating film for a bus bar is bonded to the bus bar by heating for a short time. In addition, when manufacturing a bus bar, bending is generally performed. The insulating film for a bus bar is required to be able to follow the bending process without peeling from the bus bar in the bending process.

The present invention has been made in view of the above circumstances, and is adhered by heating for a short time, can exhibit excellent adhesive strength to metal, and can follow a bending process for a bus bar insulation. It is an object to provide a film and a bus bar provided with the film.

That is, the present invention employs the following configuration.
[1] An insulating film for a bus bar to be attached to a surface of a bus bar, the insulating film having a base layer and an adhesive layer, wherein the base layer contains a resin as a forming material, and the adhesive layer is formed of phenol. An insulating film for a bus bar, comprising a resin (A), wherein when a withstand voltage test described below is performed, current is not confirmed even when the average electric field intensity reaches 5 kV / mm.
[anti-voltage test]
-Test laminate A busbar insulating film is laminated on both sides of an aluminum alloy plate having a thickness of 100 µm. At this time, an aluminum alloy plate is laminated on the adhesive layer side of the bus bar insulating film. A test laminate bonded at a temperature of 170 ° C. and a pressure of 0.4 MPa for 10 minutes is prepared. This test laminate is bent with the base layer inside, with a bending angle of 90 ° and a radius of curvature R of 1 mm. Then, it heats at temperature 180 degreeC for 10 minutes. The thickness of the base layer of the insulating film for a bus bar is 150 μm.
-Withstand voltage test Peel off the end of the test laminate after heating to expose the aluminum alloy plate, connect one terminal of the test circuit, and connect the other stainless steel terminal of the test circuit from above the base material layer. Make contact with the bent part. Thereafter, a DC voltage is applied, the applied voltage is gradually increased, and the energization is checked.
[2] The busbar insulating film according to [1], wherein the phenolic resin (A) is a solid phenolic resin, and the adhesive layer further includes a primer (B).
[3] The busbar insulating film according to [1] or [2], wherein the phenolic resin (A) is a hot-melt phenolic resin having a softening point of 30 ° C or higher.
[4] The insulating film for a bus bar according to [2] or [3], wherein the primer (B) is a modified polyolefin having a functional group introduced into the polyolefin, an epoxy resin or a phenoxy resin.
[5] The adhesive layer contains one or more crosslinking agents (C) selected from the group consisting of isocyanate resins, oxazoline group-containing resins, amino group-containing resins, polyamines, amide resins, melamine resins, and urea resins. The insulating film for a bus bar according to any one of [1] to [4].
[6] The insulating film for a bus bar has a base layer containing a resin as a forming material and an adhesive layer, and has an adhesive layer on at least one surface of the base layer, [1] to [5]. The insulating film for a bus bar according to any one of the above.
[7] The base layer is made of a fluororesin, a polyimide resin, a polyetheretherketone resin, a polyphenylenesulfide resin, a polyphenyleneether resin, a liquid crystal polyester resin, a polyester resin, a polyamide resin, a polyamideimide resin, an epoxy resin, an acrylic resin, and a polyketone. The insulation for a bus bar according to any one of [1] to [6], which comprises, as a forming material, at least one resin selected from the group consisting of a resin, a cyclic olefin resin, polymethylpentene, polypropylene, and polyethylene. the film.
[8] A bus bar comprising a plate-shaped conductor and the insulating film for a bus bar according to any one of [1] to [7].

ADVANTAGE OF THE INVENTION According to this invention, it can adhere | attach by heating for a short time, and can provide the insulating film for bus bars which demonstrates the outstanding adhesive force with respect to metal, and the bus bar provided with this.
Here, “short-time heating” means heating at a heating temperature of 100 ° C. to 200 ° C. for 5 minutes to 15 minutes.

It is a schematic diagram of the cross section of the test laminate manufactured in the example. It is a schematic diagram of the cross section when the test laminate manufactured in the example is bent. It is a schematic diagram of the cross section when the test laminate manufactured in the comparative example is bent. It is a perspective view when the test laminated body manufactured in the comparative example is bent. It is a perspective view when the test laminated body manufactured in the comparative example is bent. It is a schematic diagram for explaining the test method of the withstand voltage test. It is a schematic diagram for explaining the test method of the withstand voltage test.

Hereinafter, the present invention will be described based on preferred embodiments.

<Insulating film for busbar>
The present embodiment is an insulating film for a bus bar to be bonded to the surface of the bus bar. The insulating film for a bus bar of the present embodiment has a base material layer and an adhesive layer. The base material layer is made of resin. For this reason, when the bus bar insulating film of the present embodiment is bonded to the bus bar via the adhesive layer, the insulating property is exhibited. The adhesive layer contains a phenol resin (A).

In the insulating film for a bus bar according to the present embodiment, when the following withstand voltage test is performed, even when the average electric field intensity reaches 5 kV / mm, no current is confirmed. Here, the expression “current is not confirmed” means that a current value of 1 mA is observed when a voltage of 5 kV / mm is applied and a voltage of 5 kV / mm is maintained for 60 seconds in a withstand voltage test described later. Means not being done. Further, “dielectric breakdown” means a case where the current suddenly increases to a state where the current cannot be controlled, or a case where the insulating portion cannot limit the current.

[anti-voltage test]
-Test laminate A busbar insulating film is laminated on both sides of an aluminum alloy plate having a thickness of 100 µm. At this time, an aluminum alloy plate is laminated on the adhesive layer side of the bus bar insulating film. A test laminate bonded at a temperature of 170 ° C. and a pressure of 0.4 MPa for 10 minutes is prepared. This test laminate is bent with the base layer inside, with a bending angle of 90 ° and a radius of curvature R of 1 mm. Then, it heats at temperature 180 degreeC for 10 minutes. The thickness of the base layer of the insulating film for a bus bar is 150 μm.

The thickness of the base layer of the insulating film for a bus bar used for the test laminate may be 150 μm or less. If a test laminate is manufactured using a bus bar insulating film having a substrate layer thickness of 150 μm or less and a withstand voltage test is performed by the method described below, the effect of the present embodiment is obtained. Is played similarly. Examples of the thickness of 150 μm or less include 130 μm, 110 μm, 90 μm, 70 μm, 50 μm, and 30 μm.

When a withstand voltage test is performed using a test laminate, the average electric field strength generally increases as the thickness of the substrate layer increases. For this reason, when energization is not confirmed when a similar withstand voltage test is performed using an insulating film for a bus bar in which the thickness of the base layer is 150 μm or less, if the thickness of the base layer is changed to 150 μm, It can be inferred that energization is not confirmed.

-Withstand voltage test Peel off the end of the test laminate after heating to expose the aluminum alloy plate, connect one terminal of the test circuit, and connect the other stainless steel terminal of the test circuit from above the base material layer. It is brought into contact with the base material layer at the bent portion. Thereafter, a DC voltage is applied, the applied voltage is gradually increased, and the energization is checked.
To give an example, if a bend occurs in the bent portion, even if a stainless steel terminal is pressed from above the base material layer, the aluminum alloy plate cannot be completely covered, and the insulation will be caused by energization.

The insulating film for a bus bar of the present embodiment is manufactured using an adhesive composition described later. An insulating film for a bus bar manufactured using the adhesive composition described below exhibits high adhesive strength to metal.

When manufacturing a bus bar, bending is generally performed. The bus bar insulating film of the present embodiment exhibits high adhesive strength to metal. For this reason, the insulating film for bus bars of the present embodiment can follow the bending process without peeling from the bus bar in the bending process. Thereby, insulation can be exhibited and insulation can be maintained.

Further, the insulating film for a bus bar of the present embodiment can maintain the adhesive strength even when placed in a high temperature environment of, for example, 180 ° C. The insulating film for a bus bar of the present embodiment can exhibit the insulating property without peeling and can maintain the insulating property even when used for a bus bar which is assumed to be used in a high temperature environment.

The insulating film for a bus bar according to the present embodiment has a base material layer made of resin and a bonding layer. The busbar insulating film of the present embodiment includes an adhesive layer on at least one surface of the base layer. The adhesive layer is composed of an adhesive composition described below.

The base material layer is a fluororesin, a polyimide resin, a polyetheretherketone resin, a polyphenylenesulfide resin, a polyphenyleneether resin, a liquid crystal polyester resin, a polyester resin, a polyamide resin, a polyamideimide resin, an epoxy resin, an acrylic resin, a polyketone resin, and a cyclic resin. It is preferable that at least one resin selected from the group consisting of an olefin resin, polymethylpentene, polypropylene, and polyethylene is included as a forming material.

An example of lamination of the insulating film for a bus bar of the present embodiment will be described below.
・ Lamination example 1
A laminate in which an adhesive layer and a base layer are laminated.
・ Lamination example 2
A laminate in which a first adhesive layer / base layer / second adhesive layer is laminated in this order. However, the first adhesive layer and the second adhesive layer are both composed of an adhesive composition described later.

The thickness of the adhesive layer is not particularly limited. For example, the thickness may be 10 μm or more and 50 μm or less, or 15 μm or more and 30 μm or less. When the first adhesive layer and the second adhesive layer are provided as in Lamination Example 2, the thicknesses of the first adhesive layer and the second adhesive layer may be the same or different. .

In the present embodiment, an anchor coat agent may be applied to the surface of the base material layer to perform an easy adhesion treatment.

<Production method of insulating film for busbar>
The insulating film for busbars can be manufactured by applying an adhesive composition dispersed or dissolved in water or a solvent on a base material and drying it.

≪Adhesive composition≫
The adhesive composition used in the present embodiment includes a phenol resin (A) (hereinafter, sometimes referred to as “component (A)”) as an essential component, and further includes a primer (B) (hereinafter, referred to as “component (B)”). ) And the crosslinking agent (C), which may be hereinafter referred to as “component (C)”, as optional components.

・ Phenolic resin (A)
The phenol resin (A) is preferably a solid phenol resin. The phenol resin (A) is more preferably a hot-melt phenol resin. Specifically, novolak type phenol resin (hydroxyl equivalent: 100 g / eq to 110 g / eq, softening point: 75 ° C. to 125 ° C.), cresol type phenol resin (hydroxyl equivalent: 110 g / eq to 120 g / eq, softening point: 80 ° C. to 130 ° C.), or a mixture thereof. Examples of such a phenolic resin (A) include Bell Pearl S type manufactured by Air Water Bell Pearl Co., Ltd. By using such a phenolic resin (A), a rigid structure can be imparted to the adhesive layer after curing, and the adhesive strength is maintained even when the adhesive layer is placed in a high temperature environment of, for example, about 180 ° C.

The weight average molecular weight of the phenol resin (A) is preferably 1,000 or more, more preferably 2,000 or more, and particularly preferably 3,000 or more. Further, the weight average molecular weight of the phenol resin (A) is preferably 10,000 or less, more preferably 9,000 or less, and particularly preferably 8,000 or less. The above upper limit and lower limit can be arbitrarily combined.
When the weight average molecular weight of the phenolic resin (A) is in the above range, moisture resistance can be imparted to the adhesive composition.

The softening point of the phenolic resin (A) is preferably at least 30 ° C, more preferably at least 40 ° C. A temperature of 50 ° C. or higher is particularly preferred. The softening point of the phenolic resin (A) is preferably 160 ° C. or lower, more preferably 150 ° C. or lower, and particularly preferably 140 ° C. or lower. The above upper limit and lower limit can be arbitrarily combined.

・ Primer (B)
The primer (B) is a modified polyolefin obtained by introducing a functional group into a polyolefin. Here, the “functional group” is a functional group that interacts with the surface of the metal, and in the present embodiment, is preferably an acidic functional group such as a carboxy group or a carboxylic anhydride group. The primer (B) is a component that contributes to adhesiveness. Here, "interact with the surface of the metal" means that a chemical bond such as a hydrogen bond is formed between the polar group on the metal surface and the acidic functional group of the primer (B).

The primer (B) in the present embodiment is a polyolefin resin modified with a carboxylic acid or an anhydride thereof, and preferably has an acid functional group such as a carboxy group or a carboxylic anhydride group in the polyolefin resin.

The primer (B) can be prepared by introducing a functional group into a polyolefin. Examples of the introduction method include a copolymerization method and an acid modification method.
Examples of the copolymerization method include a method in which an acid functional group-containing monomer and an olefin are copolymerized.
Examples of the acid modification method include graft modification in which a polyolefin resin and an acid functional group-containing monomer are melt-kneaded in the presence of a radical polymerization initiator such as an organic peroxide or an aliphatic azo compound.
In the present embodiment, it is preferable to prepare the primer (B) by acid-modifying the polyolefin resin.

Examples of the polyolefin resin include polyethylene, polypropylene, poly-1-butene, polyisobutylene, a copolymer of propylene and ethylene, and a copolymer of propylene and an olefin monomer.
Examples of the olefin-based monomer for copolymerization include 1-butene, isobutylene, 1-hexene and the like.

Above all, as the primer (B), maleic anhydride-modified polypropylene is preferable from the viewpoints of adhesion, durability and the like.

··· Weight average molecular weight In this embodiment, the weight average molecular weight of the primer (B) is preferably 40,000 or more, more preferably 50,000 or more, and particularly preferably 60,000 or more. Further, it is preferably 140,000 or less, more preferably 130,000 or less, and particularly preferably 120,000 or less. The above upper limit and lower limit can be arbitrarily combined.

..Acid addition amount Examples of carboxylic acids used for modification include acrylic acid, methacrylic acid, maleic acid, nadic acid, fumaric acid, itaconic acid, crotonic acid, citraconic acid, sorbic acid, mesaconic acid, angelic acid and the like. Can be The derivatives thereof include acid anhydrides, esters, amides, imides, metal salts and the like.Specifically, for example, maleic anhydride, itaconic anhydride, citraconic anhydride, nadic anhydride, methyl acrylate, methyl acrylate, Examples include methyl methacrylate, ethyl acrylate, butyl acrylate, monoethyl maleate, acrylamide, maleic monoamide, maleimide, N-butylmaleimide, sodium acrylate, sodium methacrylate, and the like. Among these, unsaturated dicarboxylic acids and derivatives thereof are preferred, and maleic anhydride or phthalic anhydride is particularly preferred.
In the present embodiment, the carboxylic acid addition amount of the primer (B) is preferably 0.5% by mass or more and 3.0% by mass or less.

··· Melting point In the present embodiment, the melting point of the primer (B) is preferably 50 ° C or higher, more preferably 55 ° C or higher. A temperature of at least 60 ° C. is particularly preferred. The upper limit of the melting point is preferably 110 ° C. or lower, more preferably 105 ° C. or lower, and particularly preferably 100 ° C. or lower. The above upper limit and lower limit can be arbitrarily combined. In the present embodiment, the temperature is more preferably 50 ° C. or more and 100 ° C. or less.

In the present embodiment, the content of the primer (B) is preferably 10 parts by mass or more and 40 parts by mass or less, and more preferably 15 parts by mass with respect to the total of 100 parts by mass of the phenol resin (A) and the primer (B). It is more preferable that the amount be from 35 parts by mass to 35 parts by mass.

When the content of the primer (B) is equal to or more than the lower limit, the adhesive strength can be increased. When the content of the primer (B) is equal to or less than the above upper limit, the adhesive strength is maintained even in a high temperature environment of, for example, about 180 ° C.

In the present embodiment, the content of the phenol resin (A) is preferably 60 parts by mass or more and 90 parts by mass or less with respect to 100 parts by mass of the total of the phenol resin (A) and the primer (B). It is more preferable that the amount be from not less than 85 parts by mass.

When the content of the phenolic resin (A) is equal to or more than the above lower limit, the adhesive strength is maintained even in a high temperature environment of, for example, about 180 ° C. When the content of the phenol resin (A) is equal to or less than the upper limit, the adhesive strength can be increased.

・ Crosslinking agent (C)
The crosslinking agent (C) is preferably at least one selected from the group consisting of an isocyanate resin, an oxazoline group-containing resin, an amino group-containing resin, a polyamine, an amide resin, a melamine resin, and a urea resin. Among these, an isocyanate resin or an oxazoline group-containing resin is preferable.

Examples of the isocyanate resin include hexamethylene diisocyanate, isophorone diisocyanate, diphenylmethane diisocyanate, tolylene diisocyanate, and isocyanurate modified diisocyanates such as xylylene diisocyanate. Examples include polyisocyanate compounds such as adducts.

As the oxazoline group-containing resin, an oxazoline group-containing acrylic resin is preferable.

In this embodiment, the primer (B) and the cross-linking agent (C) are such that the functional group of the cross-linking agent (C) exceeds 1.0 equivalent of the functional group of the primer (B). It is preferred to be blended so as to be not more than 0.0 equivalent.

Here, the functional group of the primer (B) is an acidic functional group such as a carboxy group or a carboxylic anhydride group.
The functional group contained in the crosslinking agent (C) is an isocyanate group when the crosslinking agent (C) is an isocyanate resin, an oxazoline group when the oxazoline group-containing resin is used, and an amino group-containing resin. Is an amino group, a polyamine is an amine, an amide resin is an amide group, a melamine resin is an amide group, and a urea resin is an amino group.

In order to determine the blending amount of the crosslinking agent (C) with respect to the primer (B), first, the concentrations of the functional groups of the primer (B) and the crosslinking agent (C) are determined by potentiometric titration or indicator titration. An example in which the concentration of the functional group (acid value (-COOH) or hydroxyl value (-OH)) of the primer (B) is calculated by an indicator titration method is shown below.

[Method of measuring acid value]
1) Weigh about 3 g of a sample and put it into a 200 mL tall beaker.
2) Add 20 mL of titration solvent.
3) The liquid temperature is heated to 20 ° C. by a beaker heating device to dissolve the sample.
4) After the liquid temperature becomes constant at 20 ° C., titration is performed using a 0.1 mol / L potassium hydroxide / ethanol solution to obtain an acid value.

[Calculation of acid value]
Acid value (mg / g) = (EP1-BL1) × FA1 × C1 × K1 / SIZE
In the above formula, each symbol means the following numerical value.
EP1: titration (mL)
BL1: Blank value (0.0 mL)
FA1: Factor of titrant (1.00)
C1: concentration conversion value (5.611 mg / mL)
(0.1mol / L KOH 1mL potassium hydroxide equivalent)
K1: Coefficient (1)
SIZE: Sampling amount (g)

The concentration of the functional group obtained by the above method is such that the functional group of the crosslinking agent (C) is more than 1.0 equivalent and not more than 5.0 equivalent to 1.0 equivalent of the functional group of the primer (B). To be blended.

From the acid value of the primer (B), the specific amount (parts by mass) of the crosslinking agent (C) is calculated by the following method. First, the functional group equivalent of the primer (B) is determined by the following equation.
Functional group equivalent of primer (B) = molecular weight of KOH × 1000 / acid value

The functional group equivalent of the cross-linking agent (C) is, for example, epoxy, and can be determined by measurement according to JIS K-7236.

In the case of an isocyanate, it is determined by measurement according to JIS K-7301.
[Method for measuring isocyanate equivalent]
1) Collect 3 g of the sample in a 200 mL Erlenmeyer flask.
2) Add 20 mL of dehydrated toluene to dissolve the sample.
3) Add 20.0 mL of a 2 mol / L di-n-butylamine solution.
4) Shake to make uniform, and leave for 20 minutes or more.
5) Add 100 mL of isopropyl alcohol.
6) Perform titration using a 1 mol / L hydrochloric acid solution to determine the isocyanate equivalent.

[Calculation of isocyanate equivalent]
Isocyanate equivalent = (SIZE / ((BL1-EP1) × FA1)) × K2
EP1: titration (mL)
BL1: Blank value (39.888 mL)
FA1: Factor of titrant (1.00)
K2: coefficient (1000)
SIZE: Sampling amount (g)

Assuming that the blending amount of the primer (B) is X, the blending amount Y of the crosslinking agent (C) is represented by the following formula.
Y = functional group equivalent of crosslinking agent (C) × X / functional group equivalent of primer (B)

When the cross-linking agent (C) is blended so as to exceed the above lower limit, the adhesive strength is maintained even in a high temperature environment of, for example, about 180 ° C.

The adhesive composition used in the present embodiment has the above configuration, and thus has a high reactivity of being adhered by heating for a short time. Further, the adhesive composition used in the present embodiment has a high adhesive strength to a metal, and maintains the adhesive strength to a metal even when placed in a high-temperature environment of, for example, 180 ° C.

-Optional components The adhesive composition used in the present embodiment includes known components such as an antioxidant, a surfactant, a curing accelerator, a plasticizer, a filler, a crosslinking catalyst, a processing aid, an antioxidant, and the like. Can be appropriately compounded. These may be used alone or in combination of two or more.

··· Method for producing adhesive composition The adhesive composition is prepared by combining the phenol resin (A), the primer (B), the crosslinking agent (C), and, if necessary, any components in a batch or in an appropriate order. It can be manufactured by mixing.

<Bus bar>
According to the present embodiment, there is further provided a bus bar including the plate-shaped conductor and the bus bar insulating film according to the present embodiment. In the bus bar of this embodiment, an insulating film for a bus bar is adhered to a plate-shaped conductor via an adhesive layer, and an insulating resin base material is laminated. The bus bar of the present embodiment has high insulation reliability.

Examples of the material for forming the plate-shaped conductor include metal materials such as copper, aluminum, stainless steel, and nickel-plated copper.

Hereinafter, the present invention will be described in more detail by way of examples, but the present invention is not limited to these examples.

<Manufacture of insulating films for bus bars>
Aqueous dispersion of the adhesive compositions 1 to 10 containing the phenolic resin (A), the primer (B), and the cross-linking agent (C) shown in Table 1 at the compounding ratio shown in Table 1 and having a solid content of 50% by mass. A liquid was obtained. The "equivalent ratio" of the crosslinking agent (C) in Table 1 below is a ratio of the functional group equivalent of the crosslinking agent (C) to the 1.0 equivalent of the functional group of the primer (B). The functional group amount (acid value) of the primer (B) was calculated by the following method.

In Table 1, each symbol means the following materials.

The resulting aqueous dispersions of the adhesive compositions 1 to 10 are applied on a substrate by hand coating, and dried at 110 ° C. for 1 minute, and the substrate layer (film thickness 150 μm) / adhesive layer (film thickness 20 μm) (Examples 1 to 10 and Comparative Examples 1 to 4) were produced. The materials shown in Table 3 were used for the base layer.

In Table 3, the abbreviations of the base material layers mean the following materials.
-PI: Polyimide-PEN: Polyethylene naphthalate-PPS: Polyphenylene sulfide-COC: Cycloolefin copolymer-PP: Polypropylene

<Evaluation>
≫Production of test laminate 積層
The manufactured test laminate will be described with reference to FIG.
The test laminate 1 shown in FIG. 1 has an insulating film for a bus bar in which an adhesive layer and a base material layer are laminated in this order on both surfaces of an aluminum alloy plate 12 such that the adhesive layer is in contact with the aluminum alloy plate 12. Laminate.
In the test laminate 1, a base layer 10B, an adhesive layer 11B, an aluminum alloy plate 12, an adhesive layer 11A, and a base layer 10A are laminated in this order.
The bus bar insulating film is designed to have a length whose end protrudes 0.5 mm, and the bus bar insulating films are adhered to both ends of the test laminate 1.

-Aluminum alloy plate: A1050H-H1, dimensions were 100 µm x 10 mm x 30 mm.
-Insulating film for busbar: The dimensions were 11 mm x 31 mm.
The conditions for the heat compression bonding were a temperature of 170 ° C., a pressure of 0.4 Mpa, and a compression bonding time of 10 minutes.

≫Floating evaluation at 180 ° C≫
The test laminate 1 shown in FIG. 1 was bent. The bending angle was 90 °. In the folded state, it was heated at a temperature of 180 ° C. for 10 minutes. After heating, the adhesiveness of the insulating film for a bus bar at the bent portion in the bent state was evaluated according to the following criteria.
：: As in the cross section 2 shown in FIG. 2, the insulating film for the bus bar does not float at the bent portion, and the

adhesive layers

11A and 11B are adhered to the aluminum alloy plate 12.
Δ: As shown in section 3 in FIG. 3 or reference numeral 4 in FIG. 4, the insulating film for a bus bar at the bent portion was partially peeled and floating was confirmed, and the adhesive layer was partially peeled from the aluminum alloy plate. .
C: As indicated by reference numeral 5 in FIG. 5, the entire bent portion was peeled off and floating was confirmed, and the adhesive layer was completely separated from the aluminum alloy plate in the entire bent portion.

≪Dielectric strength test≫
A test laminate bent at a bending angle of 90 ° was prepared in the same manner as in the above {Evaluation of floating at 180 ° C.}.
As shown in FIG. 6, the insulating film for a bus bar at a position 10 mm or more away from the bent portion was peeled off to expose the aluminum alloy. The test circuit 62 connected to the withstand voltage tester 6 was connected to the exposed aluminum alloy. A stainless steel terminal 61 is connected to the withstand voltage tester 6 as the other connection terminal. The stainless terminal 61 is a stainless terminal having a diameter of 1 mm, a length of 10 mm, and a tip having a curved surface with a radius of curvature of 1 mm.

As shown in FIG. 7, the stainless steel terminal 61 was brought into contact with the bent portion. The contact locations were three points of the aluminum alloy end 7A, the center 7B of the bent portion, and the aluminum alloy end 7C, and each was contacted from above the base material layer. The aluminum alloy ends 7A and 7C are at a position of 0 mm from the end of the aluminum alloy plate, and the center 7B of the bent portion is at a position of 5 mm from the end of the aluminum alloy plate.

With the stainless steel terminal 61 in contact, a voltage was applied to a voltage of 5 kV / mm in 20 seconds, and the voltage was maintained at a voltage of 5 kV / mm for 60 seconds. The presence or absence of energization for 60 seconds was evaluated according to the following criteria. The withstand voltage test was performed based on IEC-J60950-1.

[Evaluation]
：: No energization was confirmed at all three points of 7A, 7B and 7C, and there was no dielectric breakdown.
×: Energization was confirmed at any one or more of 7A, 7B and 7C, and dielectric breakdown occurred.

≪Bending followability≫
The test laminate 1 shown in FIG. 1 was bent. The bending angle was 90 °. At this time, the bending followability was visually checked and evaluated according to the following criteria.
：: No lifting was observed in the bent portion of the bus bar insulating film.
×: Floating is confirmed in the bent portion of the bus bar insulating film.

As shown in the above results, the test laminate to which the present invention was applied was adhered by heating for a short time of 10 minutes, and exhibited a high adhesive strength. Furthermore, when the insulating film for a bus bar to which the present invention was applied was used, there was no lifting even in a high temperature environment of 180 ° C., and high adhesive strength was maintained. In addition, when the insulating film for a bus bar to which the present invention was applied was used, there was no dielectric breakdown, the bending followability was good, and the insulating property was maintained.

1: Test laminate, 10A, 10B: base material layer, 11A, 11B: adhesive layer, 12: aluminum alloy plate.

Claims

An insulating film for a bus bar to be bonded to the surface of the bus bar,
Having a base material layer and an adhesive layer,
The base material layer contains a resin as a forming material,
The adhesive layer contains a phenolic resin (A),
An insulating film for a bus bar, characterized in that when the following withstand voltage test is carried out, even when the average electric field intensity reaches 5 kV / mm, energization is not confirmed.
[anti-voltage test]
-Test laminate A busbar insulating film is laminated on both sides of an aluminum alloy plate having a thickness of 100 µm. At this time, an aluminum alloy plate is laminated on the adhesive layer side of the bus bar insulating film. A test laminate bonded at a temperature of 170 ° C. and a pressure of 0.4 MPa for 10 minutes is prepared. This test laminate is bent with the base layer inside, with a bending angle of 90 ° and a radius of curvature R of 1 mm. Then, it heats at temperature 180 degreeC for 10 minutes. The thickness of the base layer of the insulating film for a bus bar is 150 μm.
-Withstand voltage test Peel off the end of the test laminate after heating to expose the aluminum alloy plate, connect one terminal of the test circuit, and connect the other stainless steel terminal of the test circuit from above the base material layer. Make contact with the bent part. Thereafter, a DC voltage is applied, the applied voltage is gradually increased, and the energization is checked.
The phenol resin (A) is a solid phenol resin,
The insulating film for a bus bar according to claim 1, wherein the adhesive layer further includes a primer (B).
3. The busbar insulating film according to claim 1, wherein the phenolic resin (A) is a hot-melt phenolic resin having a softening point of 30 ° C. or higher. 4.
The insulating film for a bus bar according to claim 2 or 3, wherein the primer (B) is a modified polyolefin having a functional group introduced into the polyolefin, an epoxy resin, or a phenoxy resin.
The said adhesive layer contains one or more crosslinking agents (C) selected from the group consisting of isocyanate resin, oxazoline group-containing resin, amino group-containing resin, polyamine, amide resin, melamine resin, and urea resin. 5. The insulating film for a bus bar according to any one of items 1 to 4.
6. The busbar insulating film according to claim 1, further comprising: a base layer containing a resin as a forming material; and an adhesive layer, wherein at least one surface of the base layer is provided with an adhesive layer. 2. The insulating film for a bus bar according to item 1.
The base material layer is a fluororesin, a polyimide resin, a polyetheretherketone resin, a polyphenylenesulfide resin, a polyphenyleneether resin, a liquid crystal polyester resin, a polyester resin, a polyamide resin, a polyamideimide resin, an epoxy resin, an acrylic resin, a polyketone resin, and a cyclic resin. The insulating film for a bus bar according to any one of claims 1 to 6, wherein the insulating film contains at least one resin selected from the group consisting of an olefin resin, polymethylpentene, polypropylene, and polyethylene as a forming material.
A bus bar comprising a plate-shaped conductor and the bus bar insulating film according to any one of claims 1 to 7.