JP2016120699A - Insulating sheet - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an insulating sheet having a resin film excellent in heat resistance, withstand voltage characteristics and surface characteristics as a dielectric film.SOLUTION: An insulating sheet has a layer formed of a dielectric film. The dielectric film is obtained by stretching an unstretched film using a hydrogenated crystalline dicyclopentadiene ring-opened polymer, and then heating the resultant film. When a resin film is heated at a softening point of 250-320°C and a temperature of 200°C for 10 minutes, the resin film has a thermal shrinkage rate of 0.01-5.0%, surface roughness of 10-100 nm, and dielectric breakdown voltage of 300-1,000 kV/mm.SELECTED DRAWING: None

Description

  The present invention relates to an insulating sheet having, as a dielectric film, a resin film having excellent heat resistance, voltage resistance characteristics, and surface characteristics.

The insulating sheet is an electrical insulating sheet having a layer made of a dielectric film.
In recent years, insulating sheets are often used in a high-temperature environment, and are often used for applications that generate heat during driving. For this reason, the resin film used as the dielectric film of the insulating sheet is required to be superior in heat resistance.
In addition, in order to reduce the size of the insulating sheet, it has been required to make the dielectric film thinner. However, if the dielectric film is made thinner, the dielectric strength characteristics (characteristic that the insulating state is maintained even under high voltage) ) And surface characteristics (characteristics measured as surface roughness and related to adhesion with other layers).

  In relation to the present invention, Patent Document 1 describes an insulating sheet for an electric motor using polyphenylene sulfide as a dielectric film.

International Publication No. 2010/150669 Pamphlet

  As described in Patent Document 1, in recent years, demands for insulating sheets have been increasing, and in particular, those having further excellent mechanical properties, heat resistance, electrical insulation properties, and chemical resistance have been demanded.

  The present invention has been made in view of the above-described conventional technology, and an object thereof is to provide an insulating sheet having, as a dielectric film, a resin film excellent in heat resistance, voltage resistance characteristics, and surface characteristics.

  In order to solve the above problems, the present inventors have intensively studied a resin film used as a dielectric film of an insulating sheet. As a result, an unstretched film using a crystalline dicyclopentadiene ring-opening polymer hydrogenated product is stretched and then heat-treated, and is obtained by softening point, heat shrinkage rate, surface roughness. The present inventors have found that a resin film having a breakdown voltage and a dielectric breakdown voltage within specific ranges is excellent in all of heat resistance, withstand voltage characteristics, and surface characteristics, and completed the present invention.

Thus, according to the present invention, the following insulating sheets [1] to [2] are provided.
[1] An insulating sheet having a layer made of a dielectric film, wherein the dielectric film is obtained by stretching an unstretched film using a crystalline dicyclopentadiene ring-opening polymer hydrogenated product, followed by heating. It is obtained by processing and has a softening point of 250 to 320 ° C., a heat shrinkage rate of 0.01 to 5.0% when heated at 200 ° C. for 10 minutes, a surface roughness of 10 to 100 nm, and an insulating property. An insulating sheet comprising a resin film having a breakdown voltage of 300 to 1,000 kV / mm.
[2] After the resin film has been subjected to a stretching treatment on the unstretched film at a stretching temperature of 95 to 135 ° C., a stretching ratio of 1.2 to 10 times, and a stretching speed of 100 to 30,000 mm / min. The insulating sheet according to [1], which is obtained by heat treatment under conditions of a heating temperature of 150 to 240 ° C and a heating time of 0.1 to 600 minutes.

  ADVANTAGE OF THE INVENTION According to this invention, the insulating sheet which has as a dielectric film the resin film which is excellent in all of heat resistance, a withstand voltage characteristic, and a surface characteristic is provided.

    The present invention is an insulating sheet that may have a dielectric film and another insulating layer.

[Dielectric film]
The dielectric film constituting the insulating sheet of the present invention is obtained by subjecting an unstretched film formed using a crystalline dicyclopentadiene ring-opened polymer hydrogenated product to a heat treatment. A resin film having a softening point of 250 to 320 ° C., a thermal shrinkage of 0.01 to 5.0%, a surface roughness of 10 to 100 nm, and a dielectric breakdown voltage of 300 to 1,000 kV / mm (hereinafter referred to as “resin film”). (I) ").

“Crystalline dicyclopentadiene ring-opened polymer hydrogenated product” used in the production of the resin film (I) is a dicyclopentadiene ring-opened polymer hydrogenated product, and the melting point is reduced by performing a stretching treatment or the like. A film-like molded product is obtained.
As the hydrogenated crystalline dicyclopentadiene ring-opening polymer, for example, a hydrogenated dicyclopentadiene ring-opening polymer having syndiotactic stereoregularity described in JP-A-2006-52333 is used. Can be mentioned.
Hereinafter, “ring-opened polymer of dicyclopentadiene having syndiotactic stereoregularity” is referred to as “polymer (α)”, and “hydrogenated product of polymer (α)” is referred to as “polymer (β)”. There is.

  The dicyclopentadiene used for the production of the polymer (α) has endo isomers and exo isomers, both of which can be used as monomers. An isomer mixture in which an endo isomer and an exo isomer are present at an arbitrary ratio may be used. However, from the viewpoint of increasing the crystallinity of the polymer (β) and particularly improving heat resistance, it is preferable to increase the ratio of one stereoisomer. For example, the ratio of endo-form or exo-form is preferably 80% or more, more preferably 90% or more, and particularly preferably 95% or more. In addition, it is preferable that the stereoisomer which makes a ratio high is an end body from a viewpoint of synthetic | combination ease.

The polymer (α) may have a repeating unit other than the repeating unit derived from dicyclopentadiene as long as it gives a crystalline polymer (β). Such a polymer (α) can be produced by copolymerizing dicyclopentadiene and a monomer other than dicyclopentadiene.
As monomers other than dicyclopentadiene, polycyclic norbornene compounds other than dicyclopentadiene, bicyclic norbornene compounds having no ring structure condensed with norbornene skeleton, monocyclic olefins, and cyclic dienes, and these And derivatives thereof.
When these monomers are used, the amount thereof is usually more than 0% by weight and 20% by weight or less, preferably more than 0% by weight and 10% by weight or less based on the total monomers.

The catalyst used for producing the polymer (α) is not particularly limited as long as it can ring-open polymerize dicyclopentadiene to produce the polymer (α).
As such a catalyst, for example, a ring-opening polymerization catalyst containing a metal compound represented by the following formula (1) (hereinafter sometimes referred to as “metal compound (1)”) as a catalytically active component can be mentioned.

(In the formula, M is a metal atom selected from group 6 transition metal atoms in the periodic table. R ¹ may have a substituent at at least one of the 3, 4, and 5 positions. A good phenyl group or a group represented by —CH ₂ R ³ , wherein R ³ is a hydrogen atom, an alkyl group which may have a substituent, and an aryl group which may have a substituent. R ² is a group selected from an alkyl group which may have a substituent and an aryl group which may have a substituent, X is a halogen atom, an alkyl group L is a group selected from an aryl group and an alkylsilyl group, L is an electron-donating neutral ligand, a is 0 or 1, and b is an integer of 0 to 2. When X or a plurality of L are present, the plurality of X or the plurality of L may be the same as each other, It may be made to.)

  The metal atom (M) constituting the metal compound (1) is selected from group 6 transition metal atoms (chromium, molybdenum, tungsten) in the periodic table. Of these, molybdenum or tungsten is preferable, and tungsten is more preferable.

The metal compound (1) comprises a metal imide bond.
R ¹ is a substituent on the nitrogen atom constituting the metal imide bond.
Examples of the substituent of the phenyl group which may have a substituent at at least ^one of the 3, 4, and 5 positions of R ¹ include an alkyl group such as a methyl group and an ethyl group; a fluorine atom, a chlorine atom, a bromine A halogen atom such as an atom; an alkoxy group such as a methoxy group, an ethoxy group, and an isopropoxy group; and the like, and further, substituents present in at least two positions of the 3, 4, and 5 positions are bonded to each other. May be.

  Specific examples of the phenyl group which may have a substituent at at least one of the 3, 4, and 5 positions include a phenyl group; a 4-methylphenyl group, a 4-chlorophenyl group, a 3-methoxyphenyl group, 4 A monosubstituted phenyl group such as a cyclohexylphenyl group or a 4-methoxyphenyl group; a 2-substituted group such as a 3,5-dimethylphenyl group, a 3,5-dichlorophenyl group, a 3,4-dimethylphenyl group, or a 3,5-dimethoxyphenyl group; Substituted phenyl group; trisubstituted phenyl group such as 3,4,5-trimethylphenyl group and 3,4,5-trichlorophenyl group; 2-naphthyl group, 3-methyl-2-naphthyl group, 4-methyl-2- 2-naphthyl group which may have a substituent such as a naphthyl group.

The carbon number of the alkyl group which may have a substituent of R ^{3 in} the group represented by —CH ₂ R ³ of R ¹ is not particularly limited, but is usually 1 to 20, preferably 1 to 10. More preferably, it is 1-4. The alkyl group may be linear or branched. Although the substituent of this alkyl group is not specifically limited, For example, the phenyl group which may have substituents, such as a phenyl group and 4-methylphenyl group; Alkoxyl groups, such as a methoxy group and an ethoxy group, are mentioned.

Examples of the aryl group of R ³ which may have a substituent include a phenyl group, a 1-naphthyl group, and a 2-naphthyl group. The substituent of the aryl group is not particularly limited, and examples thereof include a phenyl group which may have a substituent such as a phenyl group and a 4-methylphenyl group; an alkoxyl group such as a methoxy group and an ethoxy group; Can be mentioned.
R ³ is an alkyl group having 1 to 20 carbon atoms such as a methyl group, an ethyl group, a propyl group, an isopropyl group, a butyl group, an isobutyl group, a t-butyl group, a pentyl group, a hexyl group, an octyl group, or a decyl group. Is preferred.

  X is a group selected from a halogen atom, an alkyl group, an aryl group, and an alkylsilyl group. In the metal compound (1), when there are two or more groups represented by X, these groups may be bonded to each other.

  Examples of the halogen atom for X include a chlorine atom, a bromine atom, and an iodine atom. Examples of the alkyl group of X include a methyl group, an ethyl group, a propyl group, an isopropyl group, a butyl group, an isobutyl group, a t-butyl group, a pentyl group, a neopentyl group, a benzyl group, and a neophyll group. Examples of the aryl group of X include a phenyl group, a 4-methylphenyl group, a 2,6-dimethylphenyl group, a 1-naphthyl group, and a 2-naphthyl group. Examples of the alkylsilyl group of X include a trimethylsilyl group, a triethylsilyl group, a t-butyldimethylsilyl group, and the like.

R ² is a group selected from an alkyl group which may have a substituent and an aryl group which may have a substituent. The alkyl group which may have a substituent of R ² and the aryl group which may have a substituent include the alkyl group and substituent which may have a substituent of R ³ described above. The thing similar to what was shown as an aryl group which may have this is mentioned.

L is an electron-donating neutral ligand. For example, an electron donating compound containing an atom of Group 14 or Group 15 of the Periodic Table can be used.
Specific examples thereof include phosphines such as trimethylphosphine, triisopropylphosphine, tricyclohexylphosphine, and triphenylphosphine; ethers such as diethyl ether, dibutyl ether, 1,2-dimethoxyethane, and tetrahydrofuran; trimethylamine, triethylamine, pyridine, And amines such as lutidine. Among these, ethers are preferable.

The metal compound (1) is preferably a tungsten compound having a phenylimide group (in the formula (1), M is a tungsten atom and R ¹ is a phenyl group), and tetrachlorotungsten phenylimide (tetrahydrofuran). Is more preferable.

  The metal compound (1) includes a group 6 transition metal oxyhalide, a phenyl isocyanate which may have a substituent at at least one of the 3, 4, and 5 positions, or a monosubstituted methyl isocyanate. And an electron-donating neutral ligand (L) and, if necessary, an alcohol, a metal alkoxide, a metal aryloxide, etc. (for example, a method described in JP-A-5-345817) ) Can be synthesized. The synthesized metal compound (1) may be used for the ring-opening polymerization reaction after purification and isolation by crystallization or the like, or the obtained mixed solution may be used as a catalyst solution without purification. Good.

  The amount of the metal compound (1) used as a ring-opening polymerization catalyst is usually 1: 100 to 1: 2,000,000, preferably 1: 500, in a molar ratio of (metal compound (1): monomer). ˜1: 1,000,000, more preferably in an amount of 1: 1,000 to 1: 500,000. If the amount of the catalyst is too large, it may be difficult to remove the catalyst. If the amount is too small, sufficient polymerization activity may not be obtained.

When ring-opening polymerization is performed using the metal compound (1), the metal compound (1) may be used alone, or the metal compound (1) and an organometallic reducing agent may be used in combination. By using the metal compound (1) and the organometallic reducing agent in combination, the polymerization activity may be increased.
Examples of the organometallic reducing agent include compounds of Groups 1, 2, 12, 13 and 14 of the periodic table having a hydrocarbon group having 1 to 20 carbon atoms. Among these, organolithium, organomagnesium, organozinc, organoaluminum, or organotin are preferably used, and organoaluminum or organotin are particularly preferably used.

  Examples of the organic lithium include methyl lithium, n-butyl lithium, and phenyl lithium. Examples of the organic magnesium include butyl ethyl magnesium, butyl octyl magnesium, dihexyl magnesium, ethyl magnesium chloride, n-butyl magnesium chloride, allyl magnesium bromide and the like. Examples of the organic zinc include dimethyl zinc, diethyl zinc, and diphenyl zinc. Examples of organic aluminum include trimethylaluminum, triethylaluminum, triisobutylaluminum, diethylaluminum chloride, ethylaluminum sesquichloride, ethylaluminum dichloride, diethylaluminum ethoxide, diisobutylaluminum isobutoxide, ethylaluminum diethoxide, isobutylaluminum diisobutoxide, etc. Is mentioned. Examples of the organic tin include tetramethyltin, tetra (n-butyl) tin, and tetraphenyltin.

  The amount of the organometallic reducing agent used is preferably 0.1 to 100 mol times, more preferably 0.2 to 50 mol times, and particularly preferably 0.5 to 20 mol times based on the metal compound (1). If the amount of the organic metal reducing agent used is too small, the polymerization activity may not be improved. If the amount of the organic metal reducing agent used is too large, side reactions may easily occur.

The ring-opening polymerization reaction is usually performed in an organic solvent.
The organic solvent is not particularly limited as long as the target polymer (α) or polymer (β) can be dissolved or dispersed under predetermined conditions and does not inhibit the polymerization reaction or the hydrogenation reaction. .
Specific examples of the organic solvent include aliphatic hydrocarbons such as pentane, hexane, heptane; cyclopentane, cyclohexane, methylcyclohexane, dimethylcyclohexane, trimethylcyclohexane, ethylcyclohexane, diethylcyclohexane, decahydronaphthalene, bicycloheptane, tricyclo Alicyclic hydrocarbons such as decane, hexahydroindene and cyclooctane; aromatic hydrocarbons such as benzene, toluene and xylene; halogenated aliphatic hydrocarbons such as dichloromethane, chloroform and 1,2-dichloroethane; chlorobenzene, Halogen-based aromatic hydrocarbons such as dichlorobenzene; Nitrogen-containing hydrocarbons such as nitromethane, nitrobenzene and acetonitrile; Ethers such as diethyl ether and tetrahydrofuran; or these Mixed solvents thereof. Among these solvents, aromatic hydrocarbons, aliphatic hydrocarbons, alicyclic hydrocarbons, and ethers are preferably used.

The ring-opening polymerization reaction can be initiated by mixing the monomer, the metal compound (1), and, if necessary, the organometallic reducing agent. The order in which these components are added is not particularly limited. For example, a mixture of the metal compound (1) and the organometallic reducing agent may be added to the monomer and mixed, or a mixture of the monomer and the metal compound (1) may be added to the organometallic reducing agent. The metal compound (1) may be added to and mixed with the mixture of the monomer and the organometallic reducing agent.
In mixing each component, the total amount of each component may be added at once, or may be added in multiple portions.

  The concentration of the monomer at the start of the ring-opening polymerization reaction is not particularly limited, but is preferably 1 to 50% by weight, more preferably 2 to 45% by weight, and particularly preferably 3 to 40% by weight. If the monomer concentration is too low, the productivity of the polymer (α) may decrease. If the monomer concentration is too high, the viscosity of the solution after polymerization is too high, and the subsequent hydrogenation reaction. May become difficult.

An activity regulator may be added to the polymerization reaction system. The activity regulator is used for the purpose of stabilizing the ring-opening polymerization catalyst, adjusting the polymerization reaction rate and the molecular weight distribution of the polymer.
The activity regulator is not particularly limited as long as it is an organic compound having a functional group, but is preferably an oxygen-containing organic compound, a nitrogen-containing organic compound, or a phosphorus-containing organic compound. Specifically, ethers such as diethyl ether, diisopropyl ether, dibutyl ether, anisole, furan and tetrahydrofuran; ketones such as acetone, benzophenone and cyclohexanone; esters such as ethyl acetate; nitriles such as acetonitrile benzonitrile; triethylamine , Amines such as triisopropylamine, quinuclidine, N, N-diethylaniline; pyridines such as pyridine, 2,4-lutidine, 2,6-lutidine, 2-t-butylpyridine; triphenylphosphine, tricyclohexylphosphine Phosphines such as trimethyl phosphate and triphenyl phosphate; phosphine oxides such as triphenyl phosphine oxide; and the like. These activity regulators can be used alone or in combination of two or more.
When using an activity regulator, the amount is not particularly limited, but it may be selected in the range of 0.01 to 100 mol% with respect to the metal compound (1) used as a ring-opening polymerization catalyst.

A molecular weight modifier may be added to the polymerization reaction system in order to adjust the molecular weight of the polymer (α).
Examples of molecular weight modifiers include α-olefins such as 1-butene, 1-pentene, 1-hexene and 1-octene; aromatic vinyl compounds such as styrene and vinyltoluene; ethyl vinyl ether, isobutyl vinyl ether, allyl glycidyl ether, acetic acid Oxygen-containing vinyl compounds such as allyl, allyl alcohol and glycidyl methacrylate; halogen-containing vinyl compounds such as allyl chloride; nitrogen-containing vinyl compounds such as acrylamide; 1,4-pentadiene, 1,4-hexadiene, 1,5-hexadiene, 1 , 6-heptadiene, 2-methyl-1,4-pentadiene, 2,5-dimethyl-1,5-hexadiene and other nonconjugated dienes; 1,3-butadiene, 2-methyl-1,3-butadiene, 2, 3-dimethyl-1,3-butadiene, 1,3-penta Ene, conjugated dienes such as 1,3-hexadiene; and the like.
In the case of using a molecular weight modifier, the amount may be appropriately determined according to the target molecular weight, but it is usually selected in the range of 0.1 to 50 mol% with respect to the monomer to be used.

  Although there is no restriction | limiting in particular in superposition | polymerization temperature, Usually, it is the range of -78 degreeC-+200 degreeC, Preferably it is the range of -30 degreeC-+180 degreeC. The polymerization time is not particularly limited and depends on the reaction scale, but is usually in the range of 1 minute to 1,000 hours.

  Using the ring-opening polymerization catalyst containing the metal compound (1) as described above, the polymer (α) is obtained by carrying out the ring-opening polymerization reaction of the monomer containing dicyclopentadiene under the conditions as described above. It can be manufactured efficiently.

  The ratio of racemo dyad (degree of syndiotactic stereoregularity) in the polymer (α) is usually 60% or more, preferably 65% or more, more preferably 70 to 99%. The ratio of the racemo dyad in the polymer (α) can be adjusted by selecting the type of the ring-opening polymerization catalyst.

Although the weight average molecular weight (Mw) of a polymer ((alpha)) is not specifically limited, Usually, 10,000-100,000, Preferably it is 15,000-80,000. A polymer (β) obtained by hydrogenating a polymer (α) having a weight average molecular weight within this range is more excellent in moldability. Moreover, the resin film obtained by shape | molding this polymer ((beta)) is more excellent in heat resistance.
The weight average molecular weight of a polymer ((alpha)) can be adjusted by adjusting the addition amount etc. of the molecular weight modifier used at the time of superposition | polymerization.
Although the molecular weight distribution (Mw / Mn) of a polymer ((alpha)) is not specifically limited, Usually, it is 1.5-4.0, Preferably it is 1.5-3.5. A polymer (β) obtained by hydrogenating a polymer (α) having a molecular weight distribution within this range is more excellent in moldability.
The molecular weight distribution of the polymer (α) can be adjusted by the monomer addition method and the monomer concentration during the ring-opening polymerization reaction.
The weight average molecular weight (Mw) and molecular weight distribution (Mw / Mn) are standard polystyrene equivalent values obtained by gel permeation chromatography (GPC) using tetrahydrofuran as a solvent.

A polymer (β) can be produced by performing a hydrogenation reaction of the polymer (α) (hydrogenation reaction of a main chain carbon-carbon double bond).
The hydrogenation reaction of the polymer (α) can be performed, for example, by supplying hydrogen into the reaction system in the presence of a hydrogenation catalyst. The hydrogenation catalyst is not particularly limited, and a homogeneous catalyst or a heterogeneous catalyst generally used for a hydrogenation reaction of an olefin compound can be appropriately used.

  As homogeneous catalysts, transition metal compounds such as cobalt acetate / triethylaluminum, nickel acetylacetonate / triisobutylaluminum, titanocene dichloride / n-butyllithium, zirconocene dichloride / sec-butyllithium, tetrabutoxytitanate / dimethylmagnesium and alkali Catalyst system comprising a combination of metal compounds; or dichlorobis (triphenylphosphine) palladium, chlorohydridocarbonyltris (triphenylphosphine) ruthenium, bis (tricyclohexylphosphine) benzilidineruthenium (IV) dichloride, chlorotris (triphenylphosphine) And a noble metal complex catalyst such as rhodium.

  Examples of heterogeneous catalysts include nickel / silica, nickel / diatomaceous earth, nickel / alumina, palladium / carbon, palladium / silica, palladium / diatomaceous earth, palladium / alumina, nickel, palladium, platinum, rhodium, ruthenium, or these And a solid catalyst obtained by supporting the above metal on a carrier such as carbon, silica, diatomaceous earth, alumina, and titanium oxide.

  The hydrogenation reaction is usually performed in an inert organic solvent. Examples of such inert organic solvents include aromatic hydrocarbons such as benzene and toluene; aliphatic hydrocarbons such as pentane and hexane; alicyclic hydrocarbons such as cyclohexane and decahydronaphthalene; tetrahydrofuran and ethylene glycol. And ethers such as dimethyl ether; The inert organic solvent is usually the same as the solvent used for the polymerization reaction, and the hydrogenation reaction can be carried out using a polymerization reaction solution with the hydrogenation catalyst added as it is.

The preferred reaction conditions for the hydrogenation reaction vary depending on the hydrogenation catalyst used, but the reaction temperature is usually -20 ° C to + 250 ° C, preferably -10 ° C to + 220 ° C, more preferably 0 ° C to 200 ° C. If the reaction temperature is too low, the reaction rate may be too slow, and if it is too high, side reactions may occur.
The hydrogen pressure is usually 0.01 to 20 MPa, preferably 0.05 to 15 MPa, and more preferably 0.1 to 10 MPa. If the hydrogen pressure is too low, the hydrogenation rate may be too slow, and if it is too high, there will be restrictions on the apparatus in that a high pressure reactor is required. Although reaction time is not specifically limited, Usually, it is 0.1 to 10 hours.

  The hydrogenation rate in the hydrogenation reaction (ratio of hydrogenated main chain carbon-carbon double bonds) is not particularly limited, but is preferably 70% or more, more preferably 80% or more, particularly preferably 90% or more, Most preferably, it is 99% or more. The higher the hydrogenation rate, the more the heat resistance of the polymer (β) is improved.

  In the polymer (β), the syndiotactic stereoregularity of the polymer (α) subjected to the hydrogenation reaction is usually maintained. Therefore, the polymer (β) has syndiotactic stereoregularity. The ratio of racemo dyad in the polymer (β) is not particularly limited as long as the polymer (β) has crystallinity, but is usually 60% or more, preferably 65% or more, more preferably 70 to 99%. .

The ratio of the racemo dyad in the polymer (β) was determined by applying the inverse decoupling method using a mixed solvent (volume ratio: 2/1) of 1,3,5-trichlorobenzene-d3 / orthodichlorobenzene-d4 as a solvent. ^13C -NMR measurement was performed at 200 ° C., and a signal of 43.35 ppm derived from meso dyad and 43.43 ppm derived from racemo dyad were obtained using a 127.5 ppm peak of orthodichlorobenzene-d4 as a reference shift. Based on the signal intensity ratio, the ratio of racemo dyad in the dicyclopentadiene ring-opening polymer hydrogenated product can be determined.

The polymer (β) has crystallinity (that is, a film-like molded body having a melting point is obtained). Although the temperature range of melting | fusing point is not specifically limited, Usually, it is 260-275 degreeC.
The polymer (β) having such a melting point is excellent due to a balance between moldability and heat resistance. The melting point of the polymer (β) can be adjusted by adjusting the degree of syndiotactic stereoregularity (racemo dyad ratio) or selecting the type of monomer used. .

When producing an unstretched film using the polymer (β), only the polymer (β) may be used as a raw material resin, or a resin composition containing the polymer (β) and an additive is used. It may be used.
Additives include: antioxidants such as phenolic antioxidants, phosphorus antioxidants, sulfur antioxidants; light stabilizers such as hindered amine light stabilizers; petroleum waxes, Fischer-Tropsch waxes and polyalkylene waxes Waxes such as sorbitol compounds, metal salts of organic phosphoric acid, metal salts of organic carboxylic acids, nucleating agents such as kaolin and talc; diaminostilbene derivatives, coumarin derivatives, azole derivatives (for example, benzoxazole derivatives, benzotriazole derivatives) , Benzimidazole derivatives, and benzothiazole derivatives), carbazole derivatives, pyridine derivatives, naphthalic acid derivatives, and imidazolone derivatives, etc .; benzophenone UV absorbers, salicylic acid UV absorbers, benzotriazole UV absorbers UV absorbers; inorganic fillers such as talc, silica, calcium carbonate, glass fiber; colorants; flame retardants; flame retardant aids; antistatic agents; plasticizers; near infrared absorbers; Polymer materials other than the polymer (β) such as a polymer; and the like.
When using an additive, the usage-amount of an additive will not be specifically limited unless the effect of this invention is inhibited, It can determine suitably according to the objective. The content of these additives contained in the resin composition is usually in the range of 0.001 to 5 parts by weight, preferably 0.01 to 1 part by weight with respect to 100 parts by weight of the polymer (β).

The manufacturing method of an unstretched film is not specifically limited, A well-known shaping | molding method can be utilized suitably.
Examples of the molding method include injection molding methods, extrusion molding methods, press molding methods, inflation molding methods, blow molding methods, calendar molding methods, cast molding methods, and compression molding methods. Among these, the extrusion method is preferable because the thickness of the unstretched film can be easily controlled.
In the extrusion method, the cylinder temperature (molten resin temperature) is usually 250 to 330 ° C., preferably 260 to 310 ° C., and the cast roll temperature is usually 45 to 160 ° C., preferably 45 to 130 ° C. Roll temperature is 25-150 degreeC normally, Preferably it is 45-120 degreeC.

  Although the thickness of an unstretched film is not specifically limited, Usually, 20 micrometers-1,000 micrometers, Preferably they are 30 micrometers-700 micrometers, More preferably, they are 40 micrometers-500 micrometers.

After the unstretched film is stretched, heat treatment is performed.
When the unstretched film is stretched, the stretching method is not particularly limited, and a known method can be appropriately used.
Stretching methods include uniaxial stretching in the longitudinal direction using the difference in peripheral speed on the roll side, uniaxial stretching in the lateral direction using a tenter stretching machine, and the like. Simultaneously stretching in the longitudinal direction and simultaneously stretching in the longitudinal direction using the simultaneous biaxial stretching method that stretches in the transverse direction according to the spread angle of the guide rail and the difference in peripheral speed between the rolls, then clip the both ends Biaxial stretching method such as sequential biaxial stretching method that grips and stretches in the lateral direction using a tenter stretching machine; Feeding force, pulling force or pulling force at different speeds can be applied in the lateral or longitudinal direction And a method of continuously and obliquely stretching in a direction of an arbitrary angle θ with respect to the width direction of the film using a tenter stretching machine.

  The stretching temperature is usually 95 to 135 ° C, preferably 100 to 130 ° C. When the stretching temperature is 95 ° C. or higher, the problem that the film breaks during stretching or the productivity decreases due to the clip coming off becomes difficult to occur. Moreover, when the stretching temperature is 135 ° C. or lower, a resin film having a low thermal shrinkage rate can be efficiently produced.

  The draw ratio is usually 1.2 to 10 times, preferably 1.5 to 5 times. When the draw ratio is 1.2 times or more, a resin film having a high softening point can be efficiently produced. On the other hand, when the draw ratio is 10 times or less, a resin film having excellent toughness can be efficiently produced. When the biaxial stretching method is used, the stretching ratio is defined by the product of the longitudinal and lateral stretching ratios.

  The stretching speed is usually 100 to 30,000 mm / min, preferably 1,000 to 20,000 mm / min. When the stretching speed is 100 mm / min or more, the resin film (I) having a high softening point can be efficiently produced. On the other hand, when the stretching speed is 30,000 mm / min or less, the problem that the film is broken during stretching or the productivity is lowered due to the clip coming off is less likely to occur.

When the stretched film obtained by the stretching treatment is subjected to a heat treatment, the heating method is not particularly limited, and a known method can be appropriately used.
Examples of the heating method include a method in which a stretched film is fixed on a table and then heated using a heating apparatus such as a heat treatment oven or an infrared heater.

The heating temperature is usually 150 to 240 ° C, preferably 160 to 210 ° C. When the heating temperature is in the range of 150 ° C. to 240 ° C., the resin film (I) having a small thermal shrinkage can be efficiently produced.
The heating time is usually 0.1 to 600 minutes, preferably 3 to 300 minutes. When the heating time is 0.1 minutes or more, the resin film (I) having a preferable surface roughness can be efficiently produced. On the other hand, when the heating time is 600 minutes or less, the resin film (I) having a preferable dielectric breakdown voltage can be efficiently produced.

Although the thickness of the film obtained by making it above is not specifically limited, Usually, 10 micrometers-200 micrometers, Preferably they are 15 micrometers-170 micrometers, More preferably, they are 20 micrometers-150 micrometers.
A film having a thickness within the above range is preferably used as a dielectric film of an insulating sheet.

  As described above, the resin film (I) is obtained by subjecting an unstretched film formed using a crystalline dicyclopentadiene ring-opened polymer hydrogenated product to a heat treatment, followed by a heat treatment. When the softening point is 250 to 320 ° C. and when heated at 200 ° C. for 10 minutes, the thermal shrinkage is 0.01 to 5.0%, the surface roughness is 10 to 100 nm, and the dielectric breakdown voltage is 300 to 1,000 kV / mm. It is a resin film.

The softening point of the resin film (I) is 250 to 320 ° C, preferably 250 to 300 ° C.
If the softening point of the resin film (I) is too low, the surface roughness tends to be small, and the surface characteristics at the time of producing an insulating sheet tend to be inferior. On the other hand, the resin film (I) having a softening point exceeding 320 ° C. is usually difficult to obtain.
The softening point of the resin film (I) can be increased by, for example, increasing the stretching ratio or increasing the stretching speed in the stretching process. Moreover, there exists a tendency for the resin film (I) of a higher softening point to be obtained by using the polymer ((beta)) with a high ratio of a racemo dyad and a hydrogenation rate.
The softening point of the resin film (I) can be measured by the method described in Examples.

The heat shrinkage rate of the resin film (I) when heated at 200 ° C. for 10 minutes is 0.01 to 5.0%, preferably 0.1 to 4.9%.
The resin film (I) having a too high heat shrinkage rate tends to be inferior in heat resistance. On the other hand, the resin film (I) having a thermal shrinkage rate of less than 0.01% is usually difficult to obtain.
This heat shrinkage rate can be reduced by, for example, performing a stretching process at a stretching temperature that is not too high, or performing a heating process at an appropriate temperature over a certain period of time.
The heat shrinkage rate when the resin film (I) is heated at 200 ° C. for 10 minutes can be determined by the method described in the examples.

The surface roughness of the resin film (I) is 10 to 100 nm, preferably 20 to 80 nm, more preferably 30 to 70 nm.
The resin film (I) having a surface roughness exceeding 100 nm tends to be inferior in the withstand voltage characteristics. On the other hand, the resin film (I) having a surface roughness of less than 10 nm is inferior in adhesiveness.
The surface roughness of the resin film (I) can be reduced by, for example, avoiding heating for a long time in the heat treatment. Moreover, resin film (I) with smaller surface roughness can be manufactured by reducing the amount of metal contained as an impurity in the polymer (β).
The surface roughness of the resin film (I) can be measured by the method described in the examples.

The dielectric breakdown voltage of the resin film (I) is 300 to 1,000 kV / mm, preferably 350 to 800 kV / mm, more preferably 400 to 700 kV / mm.
The resin film (I) having a dielectric breakdown voltage exceeding 1,000 kV / mm and the resin film (I) having a dielectric breakdown voltage of less than 300 kV / mm tend to be inferior in the withstand voltage characteristics.
The dielectric breakdown voltage of the resin film (I) is, for example, that in the stretching process, the stretching ratio is increased, the stretching speed is increased, or the heating process is performed at an appropriate temperature for a certain period of time. It can be made smaller. Moreover, the resin film (I) with a smaller dielectric breakdown voltage can be manufactured by using the polymer ((beta)) with a high ratio of a racemo dyad and a hydrogenation rate.
The dielectric breakdown voltage of the resin film (I) can be measured by the method described in Examples.

The resin film (I) having the above characteristics is excellent in heat resistance, withstand voltage characteristics and surface characteristics.
For example, even when the resin film (I) is heated at 220 ° C. for 10 minutes, the resin film (I) is less likely to shrink or soften and retain its shape.
In addition, since the resin film (I) has an appropriate static friction coefficient, the long resin film (I) is wound up in a roll shape, or when the resin film (I) is pulled out from the roll, When manufacturing a wound type insulating sheet, the work can be performed efficiently.

  Since it has these characteristics, resin film (I) is used as a dielectric film material of an insulating sheet.

  As the dielectric film made of the resin film (I), the resin film (I) is cut into a predetermined size, or the surface of the resin film (I) is subjected to surface treatment such as corona treatment or plasma treatment. Later, the thing cut | judged to the predetermined magnitude | size etc. is mentioned.

[Other insulation layers]
The other insulating layers constituting the insulating sheet of the present invention can be used in combination with materials conventionally known as insulating sheets.
The other insulating layer constituting the insulating sheet is not particularly limited as long as it is made of a dielectric, and examples thereof include aramid paper, a polyethylene terephthalate film, and a polyethylene naphthalate film.

As the other insulating layers can be efficiently formed an insulating layer that is thin and excellent in adhesion to the dielectric film, and it is possible to produce a smaller and excellent insulating sheet, Aramid paper is preferred.
When using aramid paper as the other insulating layer, the method of laminating with aramid paper is not particularly limited, and a method of laminating after modifying the dielectric film surface by corona treatment, plasma treatment, etc., using an adhesive The method of laminating and the like can be used as appropriate.
The other insulating layer may be a single layer or may be multilayered.

〔Insulating sheet〕
The insulating sheet of the present invention has a layer made of the dielectric film.
The insulating sheet of the present invention is not particularly limited as long as the dielectric film is made of the resin film (I).

As the insulating sheet of the present invention, a laminated insulating sheet in which a bonding surface of a dielectric film and another insulating layer is bonded using an adhesive (Japanese Patent No. 4746999, Japanese Patent Application Laid-Open No. 2006-321183); dielectric And a laminate type insulating sheet (International Publication No. 2010/150669, JP2013-2239662); etc., in which the bonding surface of the body film and the other insulating layer is directly thermally bonded.
The manufacturing method of these insulating sheets is not specifically limited, A conventionally well-known method can be utilized.

The insulating sheet of the present invention has a resin film having excellent heat resistance, voltage resistance characteristics, and surface characteristics as a dielectric film.
Therefore, even if the insulating sheet of the present invention is small, it is excellent in heat resistance and durability, and even if it is produced on an industrial scale, it is difficult for defective products to occur.
The insulating sheet of the present invention is used for transformers and electrical / electronic devices, automotive drive motors, industrial motors, wind power generator insulation materials, etc., taking advantage of the characteristics thereof, in particular, automotive drive motor insulation sheets. Is preferably used.

  Hereinafter, the present invention will be described in more detail with reference to Examples and Comparative Examples. The present invention is not limited to these examples. In the following, “parts” and “%” are based on weight unless otherwise specified.

Various physical properties were measured according to the following methods.
(1) Molecular weight of dicyclopentadiene ring-opened polymer (weight average molecular weight and number average molecular weight)
The molecular weight of the dicyclopentadiene ring-opened polymer was measured by gel permeation chromatography (GPC) using tetrahydrofuran as a solvent, and obtained as a standard polystyrene equivalent value.
System HLC-8320 (manufactured by Tosoh Corp.) was used as a measuring device, and an H type column (manufactured by Tosoh Corp.) was used as a column, and measurement was performed at 40 ° C.

(2) Hydrogenation rate of dicyclopentadiene ring-opening polymer hydrogenated product
¹ H-NMR measurement was performed to determine the hydrogenation rate of the dicyclopentadiene ring-opening polymer hydrogenated product.

(3) Ratio of racemo dyad of hydrogenated dicyclopentadiene ring-opening polymer 1,3,5-trichlorobenzene-d3 / orthodichlorobenzene-d4 mixed solvent (volume ratio: 2/1) as a solvent, The inverse decoupled method was applied, ¹³ C-NMR measurement was performed at 200 ° C., and a 43.35 ppm signal derived from meso dyad and a racemo dyad with a 127.5 ppm peak of orthodichlorobenzene-d4 as a reference shift Based on the signal intensity ratio of 43.43 ppm derived from, the ratio of racemo dyad of dicyclopentadiene ring-opening polymer hydrogenated product was determined.

(4) Softening point of resin film The obtained resin film was cut into a circle having a diameter of 5 mm at an arbitrary position to obtain a measurement sample. The obtained measurement sample was heated using a thermomechanical analyzer (SS6100, manufactured by Hitachi High-Tech Science Co., Ltd.) under a temperature rising condition of 10 ° C./min, and the softening point of the resin film was measured.

(5) Thermal contraction rate of resin film The obtained resin film was cut into a square of 500 mm x 500 mm at an arbitrary site to obtain a measurement sample. At this time, each side of the square was made to coincide with the flow direction (MD direction) and the width direction (TD direction) during the production of the resin film.
The obtained measurement sample was heated at 200 ° C. for 10 minutes using an oven, the amount of change in length in the MD direction and the TD direction before and after heating was examined, and the thermal contraction rate of the resin film was calculated. In addition, this thermal contraction rate is an average value of MD direction and TD direction.

(6) Resin film surface roughness (surface properties)
The surface roughness was measured using a laser microscope (manufactured by Keyence Corporation, VK-9700) at an arbitrary portion of the obtained resin film.

(7) Dielectric breakdown voltage (withstand voltage characteristics) of resin film
The obtained resin film was cut into a square of 500 mm × 500 mm at an arbitrary site to obtain a measurement sample.
The dielectric breakdown voltage of the obtained measurement sample was measured in the gas phase using a dielectric breakdown voltage tester (manufactured by Yasuda Seiki Seisakusho).

[Production Example 1]
In a metal pressure-resistant reaction vessel purged with nitrogen inside, 154.5 parts of cyclohexane, 42.8 parts of cyclohexane solution (concentration 70%) of dicyclopentadiene (end content 99% or more) (the amount of dicyclopentadiene is 30) Part) and 1.9 parts of 1-hexene were added, and the whole was heated to 53 ° C. with stirring.
On the other hand, 0.061 part of diethylaluminum ethoxide / n-hexane solution (concentration 19%) was added to a solution obtained by dissolving 0.014 part of tetrachlorotungstenphenylimide (tetrahydrofuran) complex in 0.70 part of toluene. The mixture was stirred for 10 minutes to prepare a catalyst solution.
While stirring the contents of the reaction vessel, this catalyst solution was added to the reactor to start the ring-opening polymerization reaction, and then the ring-opening polymerization reaction was performed for 4 hours while maintaining the entire volume at 53 ° C. Next, 0.037 parts of 1,2-ethanediol was added to the reaction vessel as a terminator, and the whole volume was heated to 60 ° C. and stirred for 1 hour to stop the polymerization reaction.
The number average molecular weight (Mn) and weight average molecular weight (Mw) of the dicyclopentadiene ring-opening polymer in the obtained reaction solution are 8,750 and 28,100, respectively, and the molecular weight distribution (Mw / Mn) is 3.21.

To the reaction solution, 1 part of a hydrotalcite-like compound (manufactured by Kyowa Chemical Industry Co., Ltd., Kyoward (registered trademark) 2000) was added as an adsorbent, heated to 60 ° C., and stirred for 1 hour. To this, 0.4 parts of a filter aid (Radiolite (registered trademark) # 1500, manufactured by Showa Chemical Industry Co., Ltd.) was added, and then a PP pleated cartridge filter (ADVANTEC Toyo Co., Ltd., TCP-HX) was used. The adsorbent was removed by filtration.
100 parts of cyclohexane and 0.0043 parts of chlorohydridocarbonyltris (triphenylphosphine) ruthenium are added to 200 parts of the dicyclopentadiene ring-opening polymer solution after filtration (30 parts of polymer amount), and the hydrogen pressure is 6 MPa, 180 ° C. The hydrogenation reaction was carried out for 4 hours. In the obtained hydrogenation reaction liquid, a polymer was deposited to form a slurry liquid.
The slurry solution was centrifuged to separate the dicyclopentadiene ring-opening polymer hydrogenated product and the solution, and the dicyclopentadiene ring-opened polymer hydrogenated product was collected by filtration. Subsequently, this was dried under reduced pressure at 60 ° C. for 24 hours to obtain 28.5 parts of a hydrogenated dicyclopentadiene ring-opening polymer having crystallinity.
The hydrogenation rate of the dicyclopentadiene ring-opening polymer hydrogenated product was 99% or more, the melting point (Tm) was 262 ° C., and the ratio of racemo dyad was 89%.

[Production Example 2]
To 100 parts of the hydrogenated dicyclopentadiene ring-opened polymer obtained in Production Example 1, tetrakis [methylene-3- (3 ′, 5′-di-t-butyl-4′-hydroxyphenyl) was used as an antioxidant. ) Propionate] 1.1 parts of methane (manufactured by BASF Japan, Irganox (registered trademark) 1010) was mixed to obtain a raw material composition. This raw material composition was charged into a twin-screw extruder (TEM-37B, manufactured by Toshiba Machine Co., Ltd.) having four die holes with an inner diameter of 3 mm, and a strand-shaped molded body was obtained by a hot melt extrusion molding method. After cooling, it was shredded with a strand cutter to obtain resin pellets.

The operating conditions of the twin screw extruder are shown below.
-Barrel set temperature: 270-280 ° C
・ Die setting temperature: 270 ℃
・ Screw speed: 145rpm
・ Feeder rotation speed: 50 rpm

[Production Example 3]
Using the resin pellet obtained in Production Example 2, a film having a thickness of 150 μm and a width of 120 mm is obtained by a hot melt extrusion film forming machine (manufactured by Optical Control Systems, Measuring Extruder Type Me-20 / 2800 V3) equipped with a T die. The unstretched film obtained was wound up into a roll at a speed of 2 m / min.

The operating conditions of the film forming machine are shown below.
・ Barrel temperature setting: 280-290 ° C
-Die temperature: 270 ° C
-Screw rotation speed: 30rpm

[Example 1]
After the unstretched film obtained in Production Example 3 was cut into a 90 mm × 90 mm square at an arbitrary site, this was placed in a small stretcher (EX10-B type, manufactured by Toyo Seiki Seisakusho Co., Ltd.), and the stretching temperature: The film was stretched under the conditions of 100 ° C., stretching ratio: 2.0 × 2.0 times, stretching speed: 10,000 mm / min.
Next, the obtained stretched film was fixed to an iron plate, and this was subjected to a heat treatment at 200 ° C. for 20 minutes using an oven to obtain a resin film for a dielectric film.
Various measurements were performed about the obtained resin film for dielectric films. The measurement results are shown in Table 1.

[Example 2]
In Example 1, the stretching ratio was changed to 3.0 × 3.0 times, the stretching speed was changed to 300 mm / min, and the stretching process was performed. Further, the heating temperature was changed to 210 ° C., and the heating process was performed. Obtained the resin film for dielectric films like Example 1, and performed various measurements about the obtained resin film for dielectric films. The measurement results are shown in Table 1.

Example 3
A resin film for a dielectric film was prepared in the same manner as in Example 1 except that in Example 1, the stretching process was performed by changing the stretching temperature to 130 ° C., and the heating process was further performed by changing the heating temperature to 150 ° C. Various measurements were performed on the obtained resin film for dielectric film. The measurement results are shown in Table 1.

Example 4
In Example 1, except that the heating time was changed to 5 minutes and the heat treatment was performed, the resin film for dielectric film was obtained in the same manner as in Example 1, and the obtained resin film for dielectric film was variously obtained. Measurements were made. The measurement results are shown in Table 1.

Example 5
In Example 1, the stretching ratio was changed to 1.5 × 1.5 times, the stretching process was performed, and the heating process was further performed by changing the heating temperature to 230 ° C. and the heating time to 100 minutes. In the same manner as in Example 1, a dielectric film resin film was obtained, and various measurements were performed on the obtained dielectric film resin film. The measurement results are shown in Table 1.

[Comparative Example 1]
In Example 1, except that the stretching temperature was changed to 140 ° C. and the stretching process was performed, a resin film was obtained in the same manner as in Example 1, and various measurements were performed on the obtained resin film. The measurement results are shown in Table 1.

[Comparative Example 2]
In Example 1, a resin film was obtained in the same manner as in Example 1 except that the stretching treatment was performed by changing the stretching ratio to 1.1 times x 1.1 times, and various measurements were performed on the obtained resin film. Went. The measurement results are shown in Table 1.
This resin film was not sufficiently crystallized and the softening point was too low. For this reason, the heat shrinkage rate could not be measured.

[Comparative Example 3]
In Example 1, a resin film was obtained in the same manner as in Example 1 except that the stretching process was performed while changing the stretching speed to 80 mm / min, and various measurements were performed on the obtained resin film. The measurement results are shown in Table 1.
This resin film was not sufficiently crystallized and the softening point was too low. For this reason, the heat shrinkage rate could not be measured.

[Comparative Example 4]
In Example 1, except that the heating temperature was changed to 250 ° C. and the heat treatment was performed, a resin film was obtained in the same manner as in Example 1, and various measurements were performed on the obtained resin film. The measurement results are shown in Table 1.

[Comparative Example 5]
In Example 1, except that the heating temperature was changed to 140 ° C. and the heat treatment was performed, a resin film was obtained in the same manner as in Example 1, and various measurements were performed on the obtained resin film. The measurement results are shown in Table 1.

[Comparative Example 6]
In Example 1, a resin film was obtained in the same manner as in Example 1 except that the heat treatment was performed while changing the heating time to 0.5 minutes, and various measurements were performed on the obtained resin film. The measurement results are shown in Table 1.

[Comparative Example 7]
In Example 1, a resin film was obtained in the same manner as in Example 1 except that the heat treatment was performed with the heating time changed to 700 minutes, and various measurements were performed on the obtained resin film. The measurement results are shown in Table 1.

The following can be seen from Table 1.
The resin films obtained in Examples 1 to 5 are excellent in heat resistance, withstand voltage characteristics, and surface characteristics.
On the other hand, the resin films obtained in Comparative Examples 1, 4 to 6 have a large heat shrinkage rate and are inferior in heat resistance.
The resin films obtained in Comparative Examples 2 and 3 have a low softening point, and these resin films are also inferior in heat resistance.
The resin films obtained in Comparative Examples 2, 3, 5, and 6 have small surface roughness and poor adhesion.
Moreover, the resin film obtained in Comparative Example 7 has a low dielectric breakdown voltage and is inferior in the withstand voltage characteristics.

Claims (2)

An insulating sheet having a layer made of a dielectric film,
The dielectric film is
It is obtained by subjecting an unstretched film formed using a crystalline dicyclopentadiene ring-opening polymer hydrogenated product to a heat treatment,
The softening point is 250-320 ° C., the heat shrinkage rate is 0.01-5.0% when heated at 200 ° C. for 10 minutes,
An insulating sheet comprising a resin film having a surface roughness of 10 to 100 nm and a dielectric breakdown voltage of 300 to 1,000 kV / mm.   The resin film is an unstretched film formed by using a crystalline dicyclopentadiene ring-opening polymer hydrogenated product, a stretching temperature of 95 to 135 ° C., a stretching ratio of 1.2 to 10 times, and a stretching speed of 100 to 100. It is what is obtained by extending | stretching on the conditions for 30,000 mm / min, and then heat-processing on the conditions whose heating temperature is 150-240 degreeC and heating time is 0.1-600 minutes. Insulating sheet.