JP5690606B2 - Electrical insulating resin sheet - Google Patents

Description

  The present invention relates to an electrically insulating resin sheet.

  Conventionally, various types of electrically insulating resin sheets are known. For example, those used by being arranged around a coil wire that is a heating element in a motor are known.

  Specifically, this type of electrically insulating resin sheet includes, for example, a polyphenylene sulfide resin having a plurality of aromatic hydrocarbons and a plurality of sulfide bonds (-S-) in the molecule, and a vinyl copolymer. The thing provided only with the electrically insulating resin layer containing is known (patent document 1).

However, such an electrically insulating resin sheet has a tracking resistance as an electrical insulating property required between a coil wire of a motor and the like, but has a tensile strength or the like due to heat generated from the coil wire or the like. There is a problem that the heat resistance may not be sufficient.
In addition, such an electrically insulating resin sheet does not necessarily have sufficient resistance to tearing force, that is, it does not necessarily have excellent tear resistance as a mechanical property required for the resin sheet. There is no problem.

JP 2007-186672 A

  This invention is made | formed in view of the said problem etc., and makes it a subject to provide the electrically insulating resin sheet excellent in tear resistance and heat resistance.

The electrically insulating resin sheet of the present invention includes a polyether polyphenylsulfone resin having a plurality of sulfonyl groups , a plurality of ether bonds, and a plurality of aromatic hydrocarbons in the molecule, and a polyamide having an aromatic hydrocarbon in the molecule. an electrically insulating resin sheet with an electrically insulating resin layer comprising a resin, a
The electrically insulating resin layer includes 1 to 45% by weight of the polyamide resin, and the polyamide resin has a dispersed phase dispersed in the polyether polyphenylsulfone resin.
In the 294 μm ² area range of the cut surface in the thickness direction of the electrically insulating resin layer, the number of dispersed phases having a shortest diameter of 0.5 μm or more is 10 or less.

  The electrically insulating resin sheet according to the present invention preferably further includes at least one sheet material, and the sheet material is preferably disposed on at least one side of the electrically insulating resin layer. With such a configuration, there is an advantage that the tear resistance and heat resistance of the electrically insulating resin sheet are further improved.

In the electrically insulating resin sheet according to the present invention, the sheet material is preferably a nonwoven fabric. When the sheet material is a nonwoven fabric, there is an advantage that delamination between the sheet material and the electrically insulating resin layer is suppressed. Moreover, it is preferable that the said sheet material is the paper produced by the wet papermaking method.
The sheet material preferably contains wholly aromatic polyamide, more preferably wholly aromatic polyamide paper containing wholly aromatic polyamide fibers. When the sheet material contains wholly aromatic polyamide, there is an advantage that the heat resistance of the electrically insulating resin sheet can be further improved.

  In the electrically insulating resin sheet according to the present invention, it is preferable that at least the electrically insulating resin layer side of the sheet material is subjected to corona treatment. By performing the corona treatment, there is an advantage that delamination between the sheet material and the electrically insulating resin layer is suppressed.

  The electrically insulating resin sheet according to the present invention is preferably used for electrical insulation.

  The electrically insulating resin sheet of the present invention has an effect of being excellent in tear resistance and heat resistance.

Sectional drawing which showed typically the cross section which cut | disconnected the electrically insulating resin sheet containing a sheet | seat material in the thickness direction. The electron micrograph of the thickness direction cut surface of the electrically insulating resin layer in Example 1. FIG. The electron micrograph of the thickness direction cut surface of the electrically insulating resin layer in Example 2. FIG. The electron micrograph of the thickness direction cut surface of the electrically insulating resin layer in Example 3. FIG. The electron micrograph of the thickness direction cut surface of the electrically insulating resin layer in Example 4. FIG. The electron micrograph of the thickness direction cut surface of the electrically insulating resin layer in a comparative example.

  Hereinafter, an embodiment of an electrically insulating resin sheet according to the present invention will be described.

The electrically insulating resin sheet of this embodiment is an electrically insulating resin sheet provided with an electrically insulating resin layer containing a polysulfone resin having a plurality of sulfonyl groups in the molecule and a thermoplastic resin other than the polysulfone resin. The electrically insulating resin layer has a dispersed phase in which a thermoplastic resin other than the polysulfone resin is dispersed in the polysulfone resin. In the 294 μm ² area range of the cut surface in the thickness direction of the electrically insulating resin layer, The number of the dispersed phases having the shortest diameter of 0.5 μm or more is 10 or less.
The electrical insulating resin sheet is further provided with at least one sheet material in that the tear resistance is further improved, and the sheet material is disposed on at least one side of the electrical insulating resin layer. Preferably it is.

In the electrically insulating resin layer, the polysulfone resin is a continuous phase, and a thermoplastic resin other than the polysulfone resin is dispersed and contained in the polysulfone resin as a discontinuous dispersed phase. .
The shape of the dispersed phase is not particularly limited, and examples of the shape of the dispersed phase include true sphere, oblate shape, plate shape, and needle shape.

In the electrically insulating resin layer, the number of the dispersed phases having the shortest diameter of 0.5 μm or more in the 294 μm ² area range of the cut surface in the thickness direction is 10 or less.
In principle, the above-mentioned 294 μm ² area range is a rectangular area range of 14 μm × 21 μm. Note that, by such the thickness of the electrically insulating resin layer is less than 14 [mu] m, if the rectangular image of 14 [mu] m × 21 [mu] m range is not obtained, the rectangle long sides so that 294Myuemu ² area coverage is more than 21 [mu] m Set and measure the shortest diameter of the dispersed phase in the image in such a rectangle.

  The thickness direction cut surface of the electrically insulating resin layer is not particularly limited as long as it is a surface cut in the thickness direction of the electrically insulating resin layer. Specifically, for example, the thickness direction cut surface of the electrically insulating resin layer formed by extrusion molding described later may be a thickness direction cut surface cut along the extrusion direction, and is a direction orthogonal to the extrusion direction. It may be a cut surface along the thickness direction.

The dispersed phase is obtained by embedding a resin insulating resin layer having a predetermined size and then creating a cut surface in the thickness direction of the electrically insulating resin layer by a polishing method, and performing a dyeing process and a conductive process. It appears as discontinuities of various shapes in an image obtained by a field emission scanning electron microscope (FE-SEM).
The dispersed phase may have various cross-sectional shapes on the cut surface in the thickness direction. Specifically, examples of the cross-sectional shape of the dispersed phase include a perfect circle, an ellipse, and a rectangle.

  Specifically, for example, a dispersed phase composed of a polyamide resin dispersed in a continuous phase of a polysulfone resin is produced by producing a cut surface in the thickness direction by the method described in the Examples, and performing a dyeing process and a conductive process, thereby producing an electric field. It appears as a black discontinuity in the image taken by the radial scanning electron microscope.

The shortest diameter of the dispersed phase is determined by the diameter of the maximum circle inscribed in each discontinuous having various shapes in an image of a rectangle in the above range by a field emission scanning electron microscope at 5000 magnifications.
Specifically, for example, in the cut surface in the thickness direction, when the cut surface shape of the dispersed phase is a rectangle having a long side of 10 times or more compared to the short side, the diameter of the maximum circle inscribed in the shape is Since the length is the short side of the rectangle, the shortest diameter of the dispersed phase is the short side length of the rectangle.

In the electrically insulating resin layer, when the number of the dispersed phases having the shortest diameter of 0.5 μm or more in the 294 μm ² area range of the cut surface in the thickness direction exceeds 10, the tear resistance of the electrically insulating resin layer and There is a risk of insufficient heat resistance.
In the electrically insulating resin layer, the number of the dispersed phases having the shortest diameter of 0.5 μm or more in the 294 μm ² area range of the cut surface in the thickness direction is preferably 0 or more and 5 or less, preferably 0.5 μm. More preferably, the number of the dispersed phases having the shortest diameter is zero.

  The thickness of the electrical insulating resin layer is not particularly limited, and is usually 1 μm to 500 μm.

The polysulfone resin has a molecular structure including a plurality of sulfonyl groups (—SO ₂ —).
Examples of the polysulfone resin include a polyethersulfone resin further including a plurality of ether bonds (—O—) in the molecule, or a polyphenylsulfone resin further including a plurality of aromatic hydrocarbons in the molecule. Moreover, as this polysulfone resin, the polyether polyphenyl sulfone resin which further contains a some ether bond and a some aromatic hydrocarbon in a molecule | numerator is mentioned.

The polysulfone resin, together with the formability of the electrically insulating resin layer is favorable, the electrically insulating in terms heat-resistant resin layer can become better ones, the polyether sulfone resin It is .

  As said polyether polyphenyl sulfone resin, what has the molecular structure of following formula (1) is preferable.

In formula (1), n is a positive integer representing the degree of polymerization, and is usually in the range of 10 to 5000.

  As the polyether polyphenylsulfone resin, commercially available products can be used. For example, “Ultra Zone E Series” manufactured by BASF, “Radel A Series” manufactured by Solvay, “ "Sumika Excel series".

In the electrically insulating resin layer, the content of the polysulfone resin is preferably 50% by weight or more, more preferably 55% by weight or more, and further preferably 70% by weight or more. The content of the polysulfone resin is preferably 99% by weight or less, more preferably 90% by weight or less, still more preferably 85% by weight or less, and most preferably 80% by weight or less. preferable.
When the content ratio of the polysulfone resin is 50% by weight or more, there is an advantage that the heat resistance of the electrically insulating resin layer is further improved. Moreover, when the content rate of the said polysulfone resin is 90 weight% or less, there exists an advantage that the tracking resistance of an electrically insulating resin layer can become more excellent.

Examples of the thermoplastic resin other than the polysulfone resin include a polyamide resin; an epoxy group-containing polyhydroxy polyether phenoxy resin formed by a reaction of bisphenols and epichlorohydrin; a plurality of oxymethylene (—CH ₂ O—) groups in the molecule. A polyacetal (POM) resin having a structure: a polyphenylene oxide (PPO) resin such as a polyphenylene ether (PPE) resin in which the basic structure of an aromatic hydrocarbon-ether bond is repeated in the molecule; an aromatic hydrocarbon-ether in the molecule Aromatic polyether ketone (PEK) resin in which the basic structure of the bond-aromatic hydrocarbon-ketone bond is repeated; aromatic hydrocarbon-ether bond-aromatic hydrocarbon-ether bond-aromatic hydrocarbon in the molecule -Aromatic poly having the basic structure of ketone bond repeated -Terketone (PEEK) resin; polyphenylene sulfide (PPS) resin having a plurality of aromatic hydrocarbons and a plurality of sulfide bonds (-S-) in the molecule; a plurality of aromatic hydrocarbons, imide bonds and ether bonds in the molecule Polyetherimide (PEI) resin having a plurality of resins; Thermoplastic polyamideimide resin having a plurality of imide bonds and a plurality of amide bonds in the molecule; Polyolefin resin such as polyethylene, polypropylene, polycycloolefin; Copolymer of acrylonitrile, butadiene and styrene Aromatic-containing vinyl resins such as polymers (ABS resins); Polyester resins such as polyethylene naphthalate (PEN) resins, polybutylene terephthalate (PBT) resins, polyethylene terephthalate (PET) resins; Polycarbonate (PC) resins Liquid crystal polymer (LCP) and the like.

The thermoplastic resin other than the polysulfone resin is the polyamide resin in that the tear resistance and heat resistance of the electrically insulating resin layer are further improved.

  The polyamide resin is obtained by polymerizing at least a polyamine compound and a polycarboxylic acid compound by dehydration condensation.

Examples of the polyamide resin include a polyamide resin having an aromatic hydrocarbon in the molecule and an aliphatic polyamide resin having only a plurality of aliphatic hydrocarbons as the hydrocarbon in the molecule. Especially, the polyamide resin which has an aromatic hydrocarbon in a molecule | numerator is used at the point that the said electrically insulating resin layer can become the thing excellent in heat resistance.

The polyamide resin having an aromatic hydrocarbon in the molecule includes an aromatic polyamide resin having only a plurality of aromatic hydrocarbons as a hydrocarbon in the molecule, an aliphatic hydrocarbon and an aromatic hydrocarbon as hydrocarbons in the molecule. And semi-aromatic polyamide resins having both of the above.
As the polyamide resin having an aromatic hydrocarbon in the molecule, it is possible to further suppress delamination between the sheet material and the electrically insulating resin layer while being excellent in heat resistance of the electrically insulating resin layer. Aromatic polyamide resins are preferred.

Specific examples of the polyamine compound used in the polymerization of the polyamide resin include a diamine compound.
Examples of the diamine compound include aliphatic diamines containing linear or branched hydrocarbon groups, alicyclic diamines containing cyclic saturated hydrocarbon groups, and aromatic diamines containing aromatic hydrocarbon groups. .

Examples of the aliphatic diamine, the alicyclic diamine, or the aromatic diamine include those represented by the following formula (2). R ₁ in the following formula (2) represents an aliphatic hydrocarbon group having 4 to 12 carbon atoms or an alicyclic hydrocarbon group having 4 to 12 carbon atoms including a cyclic saturated hydrocarbon, or Represents a hydrocarbon group containing an aromatic ring.
H ₂ N—R ₁ —NH ₂ (2)

As the aliphatic diamine, R ₁ carbon in the formula (2) is excellent in that the delamination between the sheet material and the electrically insulating resin layer can be further suppressed while being excellent in the heat resistance of the electrically insulating resin layer. Nonanediamine having a number of 9 is preferable, and a mixture of 1,9-nonanediamine and 2-methyl-1,8-octanediamine is more preferable.
Examples of the aromatic diamine include phenylenediamine and xylylenediamine.

Specific examples of the polycarboxylic acid compound used in the polymerization of the polyamide resin include a dicarboxylic acid compound.
Examples of the dicarboxylic acid compound include an aliphatic dicarboxylic acid containing a linear or branched hydrocarbon group, an alicyclic dicarboxylic acid containing a cyclic saturated hydrocarbon group, and an aromatic dicarboxylic acid containing an aromatic hydrocarbon group. Etc.

Examples of the aliphatic dicarboxylic acid, the alicyclic dicarboxylic acid, or the aromatic dicarboxylic acid include those represented by the following formula (3). R ₂ in the following formula (3) represents an aliphatic hydrocarbon group having 4 to 25 carbon atoms, or an alicyclic hydrocarbon group having 4 to 12 carbon atoms including a cyclic saturated hydrocarbon, or Represents a hydrocarbon group containing an aromatic ring.
_{HOOC-R 2 -COOH ··· (3} )

Examples of the aliphatic dicarboxylic acid include adipic acid and sebacic acid.
Examples of the aromatic dicarboxylic acid include terephthalic acid, methyl terephthalic acid, and naphthalene dicarboxylic acid. As the aromatic dicarboxylic acid, terephthalic acid can be used because the heat resistance of the polyamide resin can be further improved. Acid is preferred.

  The polyamide resin may be one obtained by polymerizing one kind of diamine compound and one kind of dicarboxylic acid compound, or may be one obtained by polymerizing a combination of plural kinds of each compound. Good. Further, if necessary, a material obtained by further polymerizing a compound other than the diamine compound and the dicarboxylic acid compound may be used.

  As described above, the polyamide resin is preferably the semi-aromatic polyamide resin. As the semi-aromatic polyamide resin, an aliphatic diamine as a diamine compound and an aromatic dicarboxylic acid as a dicarboxylic acid compound are polymerized. More preferred are those obtained by polymerizing nonanediamine as an aliphatic diamine and terephthalic acid as an aromatic dicarboxylic acid (PA9T).

Wherein the electrical insulating resin layer state, and are content 1 wt% or more of the thermoplastic resin other than the polysulfone resin is preferably 5 wt% or more, more preferably 15 wt% or more. Further, the content ratio of the polysulfone resin other than the thermoplastic resin Ri der 45 wt% or less, preferably 40 wt% or less, more preferably 30 wt% or less.
When the content of the thermoplastic resin other than the polysulfone resin is 1% by weight or more, there is an advantage that the tracking resistance of the electrically insulating resin layer can be further improved. Moreover, when the content rate of thermoplastic resins other than the said polysulfone resin is 45 weight% or less, there exists an advantage that the heat resistance of an electrically insulating resin layer can become more excellent.

Various additives may be blended in the electrically insulating resin layer as long as the effects of the present invention are not impaired.
Examples of the additive include alkylphenol resins, alkylphenol-acetylene resins, xylene resins, coumarone-indene resins, terpene resins, rosin and other tackifiers, brominated flame retardants such as polybromodiphenyl oxide and tetrabromobisphenol A, Chlorinated flame retardants such as chlorinated paraffin and perchlorocyclodecane, phosphorus flame retardants such as phosphate esters and halogen-containing phosphate esters, boron flame retardants, oxide flame retardants such as antimony trioxide, aluminum hydroxide Hydrated metal compounds such as magnesium hydroxide, phenolic, phosphorus, sulfur antioxidants, silica, clay, calcium carbonate, barium carbonate, strontium carbonate, aluminum oxide, magnesium oxide, boron nitride, silicon nitride, nitride Inorganic fibers such as aluminum Chromatography, heat stabilizers, light stabilizers, UV absorbers, lubricants, pigments, crosslinking agents, crosslinking aids, silane coupling agents, such as general plastic compounding ingredients such as titanate coupling agents. Moreover, aromatic polyamide fibers, montmorillonite having a particle size of several nm to several hundred nm, and the like can be mentioned. These additives can be used in an amount of, for example, 0.1 to 5 parts by weight with respect to 100 parts by weight of the resin mixture containing the polysulfone resin and a thermoplastic resin other than the polysulfone resin.

  Next, as a specific example of the electrically insulating resin sheet, an electrically insulating resin sheet in which sheet materials are arranged on both sides of the electrically insulating resin layer will be described and described in detail with reference to the drawings.

FIG. 1 is a cross-sectional view schematically showing a cross section obtained by cutting an electric insulating resin sheet in which a sheet material 3 is disposed on both sides of the electric insulating resin layer 2 in the thickness direction.
As shown in FIG. 1, such an electrically insulating resin sheet 1 has a plurality of sheet materials 3 bonded together with a sheet-like electrically insulating resin layer 2 interposed therebetween.

  The sheet material 3 is not particularly limited as long as it is a sheet. Moreover, thickness is not specifically limited, Usually, it is 10-100 micrometers. In addition, as shown in FIG. 1, the sheet material 3 is usually provided in two sheets of an electrically insulating resin sheet.

  Examples of the sheet material 3 include a nonwoven fabric, paper, or a film. The sheet material 3 is preferably a non-woven fabric or paper in that the tear resistance of the electrically insulating resin sheet can be improved.

Examples of the sheet material 3 include those prepared by a wet papermaking method (wet nonwoven fabric and the like), and those prepared by a dry method in the air (dry nonwoven fabric and the like).
The sheet material 3 is preferably paper produced by a wet papermaking method in that the electrical insulating resin sheet can be more excellent in tear resistance.

  Examples of the material of the sheet material 3 include synthetic polymer compounds such as polyamide and polyester, natural polymer compounds such as cellulose, and the like, and the tear resistance of the electrically insulating resin sheet can be further improved. Polyamide is preferred.

  The polyamide includes a wholly aromatic polyamide in which all of the constituent monomers have aromatic hydrocarbons, an aliphatic polyamide in which all of the constituent monomers have only aliphatic hydrocarbons, and a semi-aromatic in which some of the constituent monomers have aromatic hydrocarbons. Examples include aromatic polyamides, and wholly aromatic polyamides are preferable in that the electrical insulating resin sheet can be more excellent in tear resistance. That is, it is preferable that the sheet material 3 contains the wholly aromatic polyamide.

  The sheet material 3 is more preferably a wholly aromatic polyamide paper containing wholly aromatic polyamide fibers in that the tear resistance of the electrically insulating resin sheet can be further improved. That is, a wholly aromatic polyamide paper produced by a wet papermaking method using a wholly aromatic polyamide fiber is more preferable.

Examples of the wholly aromatic polyamide paper include, for example, a wholly aromatic polyamide fiber obtained by fiberizing a condensation polymerization product (fully aromatic polyamide) of phenylenediamine and phthalic acid, which includes a benzene ring except for an amide group. Are formed as the main constituent material.
The wholly aromatic polyamide paper is excellent in mechanical properties and preferably has a basis weight of 5 g / m ² or more in terms of good handling in the production process of the electrically insulating resin sheet. When the basis weight is 5 g / m ² or more, there is an advantage that the mechanical strength is prevented from being insufficient and is not easily broken during the production of the electrically insulating resin sheet.
In addition, other components can be added to the wholly aromatic polyamide paper as long as the effects of the present invention are not impaired. Examples of the other components include polyphenylene sulfide fibers, polyether ether ketone fibers, polyester fibers, and arylates. Examples thereof include organic fibers such as fibers, liquid crystal polyester fibers, and polyethylene naphthalate fibers, or inorganic fibers such as glass fibers, rock wool, asbestos, boron fibers, and alumina fibers.
Examples of the wholly aromatic polyamide paper include those commercially available from DuPont under the trade name “NOMEX”.

The sheet material 3 is preferably subjected to a corona treatment on the electrically insulating resin layer 2 side. By performing the corona treatment, there is an advantage that delamination between the sheet material and the electrically insulating resin layer can be further suppressed.
The corona treatment is a treatment in which one surface of the sheet material 3 in contact with the electrical insulating resin layer 2 is subjected to a discharge treatment to generate polar carboxyl groups and hydroxyl groups to roughen the surface. As the corona treatment, a conventionally known general method can be employed.

  The electrically insulating resin sheet preferably has a CTI value of 175 V or more in a tracking resistance test that serves as an index of electrical insulation. The tracking resistance test is performed by the method described in the examples.

  The electrically insulating resin sheet preferably has an end tear resistance value of 100 N / 20 mm or more as an index of tear resistance. The end resistance value is measured by the method described in the examples.

  The electrical insulating resin sheet preferably has a tensile strength remaining ratio of 60% or more after 1250 hours at 220 ° C. The residual strength rate is obtained by the method described in the examples.

  The electrical insulating resin sheet has the interlayer insulating force between the electrical insulating resin layer and the sheet material greater than the cohesive failure force of the electrical insulating resin layer and the sheet material, and thus the electrical insulation. It is preferable that it is comprised so that delamination may not be carried out between an adhesive resin layer and the said sheet | seat material.

  Then, the manufacturing method of the said electrically insulating resin sheet is demonstrated.

The electric insulating resin layer provided in the electric insulating resin sheet is a conventionally known general mixture of a resin mixture obtained by mixing a polysulfone resin and a thermoplastic resin other than the polysulfone resin while heating to a predetermined temperature. It can be produced by molding into a sheet by a method. Specifically, for example, a polysulfone resin and a thermoplastic resin other than the polysulfone resin are mixed while being heated by a general mixing means such as a kneader, a pressure kneader, a kneading roll, a Banbury mixer, or a twin screw extruder. The resin mixture can be prepared by extruding the resin mixture into a sheet by an extruder equipped with a T-die.
In addition, for example, an electrically insulating resin sheet provided with two sheet materials can be manufactured by pressing a sheet in which an electrically insulating resin layer is sandwiched between two sheet materials.

  Specifically, in the production of the electrical insulating resin sheet, these resins are mixed at a temperature at which the difference in viscosity between the polysulfone resin and a thermoplastic resin other than the polysulfone resin becomes smaller, and the resin mixture is mixed at such a temperature. In the sheet-like electrically insulating resin layer, the particle diameter of the dispersed phase of the thermoplastic resin other than the polysulfone resin described above can be reduced in the produced electrically insulating resin layer. The number of dispersed phases having a diameter of 0.5 μm or more can be reduced.

  For example, in a resin mixture in which two different types of resins exist as a dispersed phase and a continuous phase, the following relational expression (4) is established with respect to the relationship between the size of the dispersed phase and the viscosity of the two different types of resins. Are known.

As can be recognized from the relational expression (4), the particle diameter of the dispersed phase can be reduced as the difference in viscosity (η _D / η _m ) between the two resins is reduced. Also, the particle diameter of the dispersed phase can be reduced by increasing the shear rate when the resin is mixed.

  More specifically, for example, when an electrically insulating resin layer containing a polyether polyphenylsulfone resin and a polyamide resin (PA9T) is molded, the higher the temperature in the temperature range of 310 ° C to 340 ° C, The difference in melt flow rate (MFR) between the phenylsulfone resin and the polyamide resin is increased. Therefore, for example, mixing each resin at 310 ° C. rather than mixing at 340 ° C. can reduce the viscosity difference between these two types of resins and reduce the particle size of the dispersed phase of the polyamide resin. it can. That is, the number of dispersed phases having a shortest diameter of 0.5 μm or more can be reduced.

  The electrical insulating resin sheet uses an electrical insulating point, for example, an electrical insulation sheet for a motor in an automobile, an electrical insulation sheet for a transformer (transformer), and an electrical insulation for a bus bar. It can be used in sheets and the like.

The electrically insulating resin sheet of the present embodiment is as illustrated above, but the present invention is not limited to the electrically insulating resin sheet illustrated above.
Moreover, the various aspects used in a general electrically insulating resin sheet can be employed as long as the effects of the present invention are not impaired.

  For example, in the above embodiment, the electrical insulating resin sheet in which one sheet material is disposed on each side of the sheet-like electrical insulating resin layer in FIG. 1 has been described. It is not limited to the embodiment, and one sheet material may be disposed only on one side of the sheet-like electrically insulating resin layer. Alternatively, only a sheet-like electrically insulating resin layer may be provided.

  EXAMPLES Next, although an Example is given and this invention is demonstrated in more detail, this invention is not limited to these.

Example 1
First, the following raw materials were prepared.
・ Polysulfone resin: Polyether polyphenylsulfone resin (PES) resin (including multiple sulfonyl groups, ether bonds, and aromatic hydrocarbons in the molecule)
(Product name “Radel A-300A” manufactured by Solvay) was used.
・ Polyamide resin: Polyamide resin (PA9T)
(Contains multiple terephthalic acid units and nonanediamine units in the molecule)
(Kuraray brand name “Genesta N1000A”)
Next, the PES resin and the PA resin were mixed at 310 ° C. using a twin-screw kneader (manufactured by Technobel) so that the weight ratio of PES / PA = 80/20 was obtained to prepare a resin mixture.
Subsequently, the resin mixture was formed into a sheet having a thickness of 100 μm at 310 ° C. by extrusion molding to form an electrically insulating resin layer, and an electrically insulating resin sheet consisting only of the sheet-like electrically insulating resin layer was manufactured.

(Example 2)
An electrically insulating resin sheet consisting only of a sheet-like electrically insulating resin layer was produced in the same manner as in Example 1 except that a resin mixture was prepared at 320 ° C. and extruded at 320 ° C.

(Example 3)
An electrically insulating resin sheet consisting only of a sheet-like electrically insulating resin layer was produced in the same manner as in Example 1 except that a resin mixture was prepared at 330 ° C. and extruded at 330 ° C.

Example 4
On the other hand, two wholly aromatic polyamide papers (trade name “NOMEX T410”, thickness 50 μm, manufactured by DuPont) were prepared as sheet materials. Furthermore, the corona treatment was performed on the surface of each sheet material in contact with the electrically insulating resin layer. The corona treatment was performed under the conditions of an output of 500 W, a treatment speed of 4 m / min, and a sample width of 0.4 m under atmospheric pressure using “500 series” manufactured by PILLAR TECHNOLOGIES as an instrument.
And using a hot press machine heated at 350 ° C., sandwiched between two metal plates with two fully aromatic polyamide papers arranged on both sides of the electrically insulating resin layer of Example 1, The sheet was pressed at a pressure of 200 N / cm ² for 60 seconds to produce an electrically insulating resin sheet having a thickness of about 200 μm having two sheet materials on both sides of the electrically insulating resin layer.

(Comparative example)
An electrically insulating resin sheet comprising only a sheet-like electrically insulating resin layer was produced in the same manner as in Example 1 except that a resin mixture was prepared at 340 ° C. and extruded at 340 ° C.

<Preparation of sample for electron microscope observation>
A sample of an appropriate size is cut out from the electrically insulating resin layer of the electrically insulating resin sheet of each example and comparative example, and this is embedded in an epoxy resin, and polished along the extrusion direction of the extrusion. A cut surface in the thickness direction was produced.
Further, a sample subjected to electron staining with a heavy metal dye and subjected to conductive treatment by metal deposition was used as an electron microscope observation sample.

<Measurement of shortest diameter in dispersed phase of polyamide resin>
Using a field emission scanning electron microscope (FE-SEM) “product name S-4800, manufactured by Hitachi, Ltd.”, the observation voltage was 10 kV and the magnification was 5000 times, and the measurement was 14 μm (thickness direction) × 21 μm (extrusion direction MD). In the rectangular range, the produced electron microscope observation sample was observed.
As described above, the shortest diameter of the dispersed phase was determined by the diameter of the largest circle inscribed in each discontinuous for each of the polyamide resin dispersed phases that appeared to be black discontinuities. In this measurement, each dispersed phase was distinguished visually.

  The electron micrograph of the thickness direction cut surface in the electrically insulating resin layer of each Example and a comparative example is shown in FIGS. 2 to 6 show the examples in Examples 1 to 4 and the comparative example, respectively.

<Evaluation of heat resistance>
A test sample cut at a width of 15 mm along the flow direction of the electrically insulating resin layer in the manufactured electrically insulating resin sheet was prepared. The prepared test sample was left in a thermostatic chamber heated to 220 ° C. for 1250 hours. About the test sample before and after leaving to stand in a thermostat, according to "tensile characteristic" in JISC2151, the tensile test was performed at 23 degreeC on the test conditions of 200 mm / min and a 100-mm mark, and measured the tensile strength. And the intensity | strength residual rate was computed by the following formula.
Strength remaining ratio (%) = {(Tensile strength after leaving) / (Tensile strength before leaving)} × 100

<Evaluation of tear resistance>
In accordance with “end tear resistance (Method B)” in JIS C2151, the end tear resistance value at the time of tearing along the longitudinal direction (extrusion direction MD) of the electrically insulating resin sheet was measured at 23 ° C.

<Evaluation of tracking resistance>
A CTI (Comparative Tracking Index) value was measured at 23 ° C. in accordance with JIS C2134.

  Table 1 shows the evaluation results of heat resistance (strength residual rate), tear resistance (end tear resistance value), and tracking resistance (CTI value) in each example and each comparative example.

  The electrically insulating resin sheet of the present invention can be suitably used as an electrically insulating sheet that requires heat resistance and electrical insulation. Specifically, for example, an electrical insulating sheet material arranged around the coil wire of a motor, a transformer, a bus bar, a capacitor, an electrical insulating sheet material for a cable, or an insulating film of an electronic circuit board. Is preferred.

1: electrically insulating resin sheet, 2: electrically insulating resin layer, 3: sheet material

Claims (14)

A polyether sulfone resin having a plurality of sulfonyl groups in the molecule and a plurality of ether linkages and a plurality of aromatic hydrocarbons, electrically insulating resin layer comprising a polyamide resin, a having an aromatic hydrocarbon in a molecule An electrically insulating resin sheet comprising:
The electrically insulating resin layer includes 1 to 45% by weight of the polyamide resin, and the polyamide resin has a dispersed phase dispersed in the polyether polyphenylsulfone resin.
Wherein in the 294Myuemu ² area range in the thickness direction cross section of the electrically insulating resin layer, the number of the dispersed phase having a shortest diameter of more than 0.5μm is 10 or less, the electrically insulating resin sheet. The polyamide resin is a semi-aromatic polyamide resin having said aromatic hydrocarbon and an aliphatic hydrocarbon in a molecule, the electrically insulating resin sheet according to claim 1, wherein. The electrically insulating resin sheet according to claim 2 , wherein the semiaromatic polyamide resin is a polyamide resin obtained by polymerizing nonanediamine containing the aliphatic hydrocarbon and terephthalic acid containing the aromatic hydrocarbon . At least one further comprising a sheet material, the sheet material is disposed on at least one surface side of the electrically insulating resin layer, electrically insulating resin sheet according to any one of claims 1-3. The electrically insulating resin sheet according to claim 4 , wherein the sheet material contains wholly aromatic polyamide. The sheet material is a paper made by a wet papermaking method, the electrically insulating resin sheet according to claim 4 or 5, wherein. The sheet material is a wholly aromatic polyamide paper comprising wholly aromatic polyamide fibers, electrically insulating resin sheet according to any one of claims 4-6. The electrically insulating resin sheet according to claim 4 or 5 , wherein the sheet material is a nonwoven fabric. At least the electrically insulating resin layer side, the corona treatment is applied, the electrically insulating resin sheet according to any one of claims 4-8 of the sheet material. The interlayer insulating force between the electrical insulating resin layer and the sheet material is greater than the respective cohesive failure forces of the electrical insulating resin layer and the sheet material, whereby the electrical insulating resin layer and the sheet material It is configured so as not to delaminate between the electrically insulating resin sheet according to any one of claims 4-9. The electrically insulating resin sheet according to any one of claims 1 to 10 , wherein a CTI value of a tracking resistance test is 175 V or more. Edge-cracking resistance of at 100 N / 20 mm or more, the electrically insulating resin sheet according to any one of claims 1 to 11. Strength retention of tensile strength after a 1250 hours at 220 ° C. is 60% or more, the electrically insulating resin sheet according to any one of claims 1 to 12. The electrically insulating resin sheet according to any one of claims 1 to 13 , which is used in an electrically insulating application.