JP6543929B2 - Insulating sheet - Google Patents

Description

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

An insulating sheet is a sheet for electrical insulation which has a layer which consists of dielectric films.
In recent years, insulating sheets are often used in high-temperature environments, and often used for applications that generate heat when driven. For this reason, the resin film used as the dielectric film of the insulating sheet is required to be more excellent in heat resistance.
Moreover, in order to miniaturize the insulating sheet, it has been required to make the dielectric film thinner. However, when the dielectric film is made thinner, the withstand voltage characteristics (characteristic that the insulation state is maintained even under high voltage) And surface characteristics (characteristics measured as surface roughness and related to adhesion with other layers) tend to be inferior.

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

International Publication No. 2010/150669 Pamphlet

  As described in Patent Document 1, in recent years, while the performance required for the insulating sheet is increased, it is desired to further improve the mechanical properties, heat resistance, electrical insulation and chemical resistance.

  The present invention is made in view of the above-mentioned prior art, and it aims at providing an insulating sheet which has a resin film which is excellent in heat resistance, withstand voltage characteristics, and surface characteristics as a dielectric film.

  MEANS TO SOLVE THE PROBLEM The present inventors earnestly examined about the resin film used as a dielectric material film of an insulation sheet, in order to solve the said subject. As a result, it is obtained by subjecting an unstretched film formed using a hydrogenated dicyclopentadiene ring-opened polymer to a stretching treatment and then heat treatment, and the softening point, the heat shrinkage, and the surface roughness. It has been found that a resin film having a thickness and a dielectric breakdown voltage within specific ranges, respectively, is excellent in all of heat resistance, voltage resistance characteristics and surface characteristics, and the present invention has been completed.

Thus, according to the present invention, the following insulating sheets [1] and [2] are provided.
[1] An insulating sheet having a layer formed of a dielectric film, wherein the dielectric film is subjected to a stretching treatment after stretching an unstretched film formed of a hydrogenated dicyclopentadiene ring-opened polymer hydrogenated substance and then heated. Heat resistance is 0.01 to 5.0%, surface roughness is 10 to 100 nm, insulation when heated at a softening point of 250 to 320 ° C for 10 minutes at 200 ° C. An insulation sheet comprising a resin film having a breakdown voltage of 300 to 1,000 kV / mm.
[2] The resin film stretches the unstretched film under conditions of 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 insulation sheet which has as a dielectric film the resin film which is excellent in all of heat resistance, a withstand voltage characteristic, and surface characteristics 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 hydrogenated dicyclopentadiene ring-opened polymer to stretching treatment and then heat treatment. , A resin film with 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 breakdown voltage of 300 to 1,000 kV / mm (hereinafter referred to as "resin film (I) ”.

The “crystalline dicyclopentadiene ring-opened polymer hydrogenated substance” used for the production of the resin film (I) is a dicyclopentadiene ring-opened polymer hydrogenated substance, and the melting point is increased by performing stretching treatment and the like. A film-like molded product is obtained.
The hydrogenated dicyclopentadiene ring-opened polymer hydrogenated substance is, for example, a hydrogenated product of a ring-opened polymer of dicyclopentadiene having syndiotactic stereoregularity described in JP-A-2006-52333. It 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)" It is said that.

  Although dicyclopentadiene used for the production of the polymer (α) has stereoisomers of endo form and exo form, both of them can be used as monomers, and one isomer can be used alone. You may use and you may use the isomer mixture in which an endo body and an exo body exist in arbitrary ratios. However, from the viewpoint of enhancing the crystallinity of the polymer (β) and making the heat resistance particularly good, it is preferable to increase the proportion of one stereoisomer. For example, the proportion of endo or exo 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 polymer (β) having crystallinity. 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 fused to norbornene skeleton, monocyclic olefins, and cyclic dienes, and these Derivatives of
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 all monomers.

The catalyst used for the production of the polymer (α) is not particularly limited as long as it is capable of ring-opening polymerization of 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.

(Wherein, M is a metal atom selected from transition metal atoms of Group 6 of the periodic table. R ¹ may have a substituent at at least one of positions 3, 4 and 5 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 And L is an electron donating neutral ligand, a is 0 or 1, b is an integer of 0 to 2. plural When X or a plurality of L are present, the plurality of X or a plurality of L may be identical to each other, or It may be made to.)

  The metal atom (M) constituting the metal compound (1) is selected from transition metal atoms (chromium, molybdenum, tungsten) of Group 6 of the periodic table. Among them, 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.
As a substituent of the phenyl group which may have a substituent at at least one position of 3, 4 and 5 positions of R ¹ , an alkyl group such as methyl group and ethyl group; a fluorine atom, a chlorine atom, bromine Halogen atoms such as atoms; alkoxy groups such as methoxy, ethoxy and isopropoxy; and the like, and further, substituents present in at least two positions of 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 position of 3, 4 and 5 positions include phenyl group; 4-methylphenyl group, 4-chlorophenyl group, 3-methoxyphenyl group, 4 Mono-substituted phenyl groups such as cyclohexylphenyl group and 4-methoxyphenyl group; 3,5-dimethylphenyl group, 3,5-dichlorophenyl group, 3,4-dimethylphenyl group, 3,5-dimethoxyphenyl group and the like 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-yl group And 2-naphthyl group which may have a substituent such as naphthyl group.

The carbon number of the optionally substituted alkyl group 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 And more preferably 1 to 4. The alkyl group may be linear or branched. The substituent of this alkyl group is not particularly limited, and examples thereof include a phenyl group which may have a substituent such as phenyl group and 4-methylphenyl group; and an alkoxyl group such as methoxy group and ethoxy group.

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

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

  As a halogen atom of X, a chlorine atom, a bromine atom, and an iodine atom are mentioned. 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 neophyl group. As an aryl group of X, a phenyl group, 4-methylphenyl group, 2, 6- dimethylphenyl group, 1-naphthyl group, 2-naphthyl group etc. are mentioned. Examples of the alkylsilyl group of X include a trimethylsilyl group, a triethylsilyl group, and a t-butyldimethylsilyl group.

R ² is a group selected from an alkyl group which may have a substituent and an aryl group which may have a substituent. As the alkyl group which may have a substituent or the aryl group which may have a substituent of R ² , the alkyl group which may have a substituent or substituent of R ³ described above And the same as those described as the optionally substituted aryl group.

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 mentioned.
Specific examples thereof include phosphines such as trimethyl phosphine, triisopropyl phosphine, tricyclohexyl phosphine and triphenyl phosphine; 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.

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

  The metal compound (1) is 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 (E.g., the method described in JP-A-5-345817), etc. by mixing the organic group with an electron-donating neutral ligand (L) and, if necessary, an alcohol, a metal alkoxide, a metal aryloxide Can be synthesized by The synthesized metal compound (1) may be used for ring-opening polymerization reaction after purification and isolation by crystallization etc., or even if it is used as a catalyst liquid without purification, the obtained liquid mixture is used as it is Good.

  The amount of metal compound (1) used as the ring-opening polymerization catalyst is usually 1: 100 to 1: 2,000,000, preferably 1: 500, in terms of the molar ratio of (metal compound (1): monomer) It is an amount of about 1: 1,000,000, more preferably 1: 1,000 to 1: 500,000. When the amount of the catalyst is too large, the removal of the catalyst may be difficult, and when 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 the organometallic reducing agent may be used in combination. The polymerization activity may be increased by using the metal compound (1) and the organic metal reducing agent in combination.
As an organometallic reducing agent, the compound of periodic table group 1, 2, 12, 13, 14 which has a C1-C20 hydrocarbon group is mentioned. Among them, organic lithium, organic magnesium, organic zinc, organic aluminum or organic tin is preferably used, and organic aluminum or organic tin is particularly preferably used.

  Examples of the organic lithium include methyllithium, n-butyllithium and phenyllithium. Examples of the organic magnesium include butylethyl magnesium, butyl octyl magnesium, dihexyl magnesium, ethyl magnesium chloride, n-butyl magnesium chloride, allyl magnesium bromide and the like. Examples of organic zinc include dimethyl zinc, diethyl zinc, diphenyl zinc and the like. As organoaluminum, trimethylaluminum, triethylaluminum, triisobutylaluminum, diethylaluminum chloride, ethylaluminum sesquichloride, ethylaluminum dichloride, diethylaluminum ethoxide, diisobutylaluminum isobutoxide, ethylaluminum diethoxide, isobutylaluminum diisobutoxide, etc. Can be mentioned. Examples of the organic tin include tetramethyl tin, tetra (n-butyl) tin, tetraphenyl tin and the like.

  The amount of use of the organometallic reducing agent is preferably 0.1 to 100 moles, more preferably 0.2 to 50 moles, and particularly preferably 0.5 to 20 moles, per mole of the metal compound (1). If the amount of the organic metal reducing agent used is too small, the polymerization activity may not be improved, and 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 carried out in an organic solvent.
The organic solvent is not particularly limited as long as it can dissolve or disperse the target polymer (α) or polymer (β) 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 and 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; halogen-based 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 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.
When mixing each component, the whole quantity of each component may be added at once, and may be divided and added in multiple times.

  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 concentration of the monomer is too low, the productivity of the polymer (α) may be reduced. If the concentration of the monomer is too high, the viscosity of the solution after polymerization is too high, and the subsequent hydrogenation reaction May be difficult.

An activity regulator may be added to the polymerization reaction system. The activity modifier is used for the purpose of stabilizing the ring-opening polymerization catalyst, the rate of the polymerization reaction, 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 oxygen-containing organic compounds, nitrogen-containing organic compounds, and phosphorus-containing organic compounds are preferable. 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 And phosphines; phosphates such as trimethyl phosphate and triphenyl phosphate; phosphine oxides such as triphenyl phosphine oxide; and the like. These activity modifiers can be used singly or in combination of two or more.
When the activity regulator is used, the amount thereof is not particularly limited, but generally, it may be selected in the range of 0.01 to 100% by mole 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).
As molecular weight modifiers, α-olefins such as 1-butene, 1-pentene, 1-hexene, 1-octene, etc .; aromatic vinyl compounds such as styrene, vinyl toluene; 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 Non-conjugated dienes such as 2,6-heptadiene, 2-methyl-1,4-pentadiene, 2,5-dimethyl-1,5-hexadiene; 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.
When a molecular weight modifier is used, the amount thereof may be suitably determined in accordance with the target molecular weight, but in general, it may be selected in the range of 0.1 to 50 mol% with respect to the monomer to be used.

  The polymerization temperature is not particularly limited, but is usually in the range of -78 ° C to + 200 ° C, preferably in the range of -30 ° C to + 180 ° C. 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.

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

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

The weight average molecular weight (Mw) of the polymer (α) is not particularly limited, but is usually 10,000 to 100,000, preferably 15,000 to 80,000. The polymer (β) obtained by hydrogenating the polymer (α) having a weight average molecular weight in this range is more excellent in moldability. Moreover, the resin film obtained by shape | molding this polymer ((beta)) is excellent by heat resistance.
The weight average molecular weight of the polymer (α) can be adjusted by adjusting the addition amount of the molecular weight modifier used at the time of polymerization.
The molecular weight distribution (Mw / Mn) of the polymer (α) is not particularly limited, but is usually 1.5 to 4.0, preferably 1.5 to 3.5. The polymer (β) obtained by hydrogenating the polymer (α) having a molecular weight distribution in this range is more excellent in moldability.
The molecular weight distribution of the polymer (α) can be adjusted by the addition method of the monomer at the time of the ring-opening polymerization reaction or the concentration of the monomer.
The above 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.

The polymer (β) can be produced by carrying out a hydrogenation reaction (hydrogenation reaction of main chain carbon-carbon double bond) of the polymer (α).
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 homogeneous catalysts and heterogeneous catalysts generally used in the hydrogenation reaction of olefin compounds can be appropriately used.

  Examples of homogeneous catalysts include transition metal compounds such as cobalt acetate / triethylaluminum, nickel acetylacetonate / triisobutylaluminum, titanocene dichloride / n-butyllithium, zirconocene dichloride / sec-butyllithium, tetrabutoxytitanate / dimethylmagnesium and alkalis Catalyst systems consisting of combinations of metal compounds; or dichlorobis (triphenylphosphine) palladium, chlorohydridocarbonyltris (triphenylphosphine) ruthenium, bis (tricyclohexylphosphine) benziridineruthenium (IV) dichloride, chlorotris (triphenylphosphine) Noble metal complex catalysts such as rhodium;

  Heterogeneous catalysts include nickel / silica, nickel / diatomaceous earth, nickel / alumina, palladium / carbon, palladium / silica, palladium / diatomaceous earth, palladium / alumina, etc., nickel, palladium, platinum, rhodium, ruthenium, or these These catalysts are supported on a carrier such as carbon, silica, diatomaceous earth, alumina, titanium oxide, etc.

  The hydrogenation reaction is usually carried out in an inert organic solvent. As such inert organic solvents, aromatic hydrocarbons such as benzene and toluene; aliphatic hydrocarbons such as pentane and hexane; alicyclic hydrocarbons such as cyclohexane and decahydronaphthalene; tetrahydrofuran, ethylene glycol Ethers such as dimethyl ether; and the like. The inert organic solvent is usually the same as the solvent used for the polymerization reaction, and the hydrogenation reaction can be performed using the polymerization reaction solution to which the hydrogenation catalyst is added as it is.

The preferred reaction conditions for the hydrogenation reaction depend on the hydrogenation catalyst used, but the reaction temperature is generally -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, 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, equipment limitations arise in that a high pressure resistant reactor is required. The reaction time is not particularly limited, but is usually 0.1 to 10 hours.

  The hydrogenation rate (proportion of hydrogenated main chain carbon-carbon double bond) in the hydrogenation reaction 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 degree of hydrogenation, the better the heat resistance of the polymer (β).

  In the polymer (β), generally, syndiotactic stereoregularity possessed by the polymer (α) subjected to the hydrogenation reaction is maintained. Thus, the polymer (β) has syndiotactic stereoregularity. The proportion of racemo dyads 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 racemo dyad of the polymer (β) was determined by applying the inverse decoupling method using a solvent mixture of 1,3,5-trichlorobenzene-d3 / orthodichlorobenzene-d4 (volume ratio: 2/1) as a solvent. ¹³ C-NMR measurement at 200 ° C., and using the peak at 127.5 ppm of ortho-dichlorobenzene-d4 as a reference shift, the 43.35 ppm signal derived from meso dyad and 43.43 ppm derived from racemo dyad Based on the intensity ratio of the signals, the ratio of racemo dyads of the dicyclopentadiene ring-opened polymer hydrogenated substance can be determined.

The polymer (β) is one having crystallinity (ie, one from which a film-like shaped product 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 more excellent in the balance between moldability and heat resistance. The melting point of the polymer (β) can be adjusted by adjusting the degree of syndiotactic stereoregularity (ratio of racemo and dyad), selecting the kind of monomer to be used, etc. .

When producing an unstretched film using a polymer (β), only a polymer (β) may be used as a raw material resin, or a resin composition containing a polymer (β) and an additive may be used. You may use.
Additives include antioxidants such as phenol-based antioxidants, phosphorus-based antioxidants, sulfur-based antioxidants; light stabilizers such as hindered amine-based light stabilizers; petroleum-based wax, Fischer-Tropsch wax and polyalkylene wax Waxes such as sorbitol; 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 , Benzoimidazole derivatives, and benzothiasol derivatives), carbazole derivatives, pyridine derivatives, naphthalic acid derivatives, and imidazolone derivatives; fluorescent whitening agents such as benzophenone based ultraviolet light absorbers, salicylic acid based ultraviolet light absorbers, benzotriazole based ultraviolet light absorbers UV absorbers; inorganic fillers such as talc, silica, calcium carbonate and glass fibers; colorants; flame retardants; flame retardant aids; antistatic agents; plasticizers; near infrared absorbers; lubricants; Polymer materials other than polymer ((beta)), such as a polymer ;;
When an additive is used, the amount of the additive used is not particularly limited as long as the effects of the present invention are not impaired, and can be appropriately determined according to the purpose. 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 parts by weight, per 100 parts by weight of the polymer (β).

The method for producing the unstretched film is not particularly limited, and a known molding method can be appropriately used.
Examples of the molding method include injection molding method, extrusion molding method, press molding method, inflation molding method, blow molding method, calendar molding method, cast molding method, compression molding method and the like. Among these, the extrusion molding method is preferable because the thickness of the unstretched film can be easily controlled.
In the extrusion molding 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. The roll temperature is usually 25 to 150 ° C, preferably 45 to 120 ° C.

  The thickness of the unstretched film is not particularly limited, but is usually 20 μm to 1,000 μm, preferably 30 μm to 700 μm, and more preferably 40 μm to 500 μm.

After stretching the unstretched film, heat treatment is performed.
When the unstretched film is stretched, the stretching method is not particularly limited, and known methods can be appropriately used.
As a stretching method, a method of uniaxially stretching in the longitudinal direction by utilizing a difference in peripheral speed on the roll side, a method of uniaxially stretching in the transverse direction by using a tenter stretching machine, etc. Simultaneously with stretching in the longitudinal direction and simultaneously with stretching in the longitudinal direction using the simultaneous biaxial stretching method of stretching in the lateral direction according to the spread angle of the guide rails and the difference in peripheral speed between the rolls, Biaxial stretching method such as sequential biaxial stretching method in which gripping and stretching in the lateral direction using a tenter stretching machine; to be able to apply feed force or tension force or take-up force at different speeds laterally in the lateral or longitudinal direction A method of obliquely stretching continuously in the direction of an arbitrary angle θ with respect to the width direction of the film using a tenter stretching machine, and the like.

  The stretching temperature is usually 95 to 135 ° C, preferably 100 to 130 ° C. When the stretching temperature is 95 ° C. or higher, problems such as breakage of the film at the time of stretching and reduction in productivity due to removal of the clip hardly occur. In addition, when the stretching temperature is 135 ° C. or less, a resin film having a small thermal contraction rate can be efficiently produced.

  The stretching 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, the resin film which is excellent in toughness can be efficiently manufactured because a draw ratio is 10 times or less. In addition, when a biaxial stretching method is used, a draw ratio is prescribed | regulated by the product of the draw ratio of length and width.

  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, problems such as breakage of the film at the time of stretching or reduction in productivity due to clip removal hardly occur.

When heat-processing the stretched film obtained by the said extending | stretching process, a heating method is not specifically limited, A well-known method can be utilized suitably.
As a heating method, after fixing a stretched film to a stand, the method of heating this using heating apparatuses, such as a heat processing oven and an infrared heater, is mentioned.

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 contraction rate 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.

The thickness of the film obtained as described above is not particularly limited, but is usually 10 μm to 200 μm, preferably 15 μm to 170 μm, and more preferably 20 μm to 150 μm.
The film whose thickness is in 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 hydrogenated dicyclopentadiene ring-opened polymer to a stretching treatment and then heat treatment, 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 when the softening point is heated at 250 to 320 ° C and 200 ° C for 10 minutes. 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 the insulating sheet are likely to be inferior. On the other hand, resin film (I) whose softening point exceeds 320 ° C. is usually difficult to obtain.
The softening point of the resin film (I) can be increased, for example, by increasing the draw ratio or increasing the drawing rate in the drawing treatment. Moreover, there is a tendency that a resin film (I) having a higher softening point can be obtained by using a polymer (β) having a high rate of hydrogenation and a ratio of racemo dyad.
The softening point of the resin film (I) can be measured by the method described in the examples.

The heat shrinkage 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 an excessively large heat shrinkage ratio tends to be inferior in heat resistance. On the other hand, the resin film (I) having a heat shrinkage of less than 0.01% is usually difficult to obtain.
The heat shrinkage ratio can be reduced, for example, by performing the stretching process at a stretching temperature that is not too high, or by performing the heat process over a certain amount of time that is an appropriate temperature.
The thermal contraction 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.
Resin film (I) whose surface roughness exceeds 100 nm tends to be inferior in withstand voltage characteristics. On the other hand, resin film (I) whose surface roughness is less than 10 nm is inferior in adhesiveness.
The surface roughness of the resin film (I) can be reduced, for example, by avoiding long-time heating in heat treatment. Moreover, resin film (I) with smaller surface roughness can be manufactured by lowering | hanging the metal amount contained as an impurity in a polymer ((beta)).
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, and more preferably 400 to 700 kV / mm.
Resin films (I) having a dielectric breakdown voltage exceeding 1,000 kV / mm and resin films (I) having less than 300 kV / mm are likely to be inferior in withstand voltage characteristics.
The dielectric breakdown voltage of the resin film (I) is, for example, to increase the draw ratio or to increase the drawing rate in the drawing treatment, or to carry out the heat treatment over a certain time at an appropriate temperature. Can be made smaller. Moreover, resin film (I) with a smaller dielectric breakdown voltage can be manufactured by using a 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 the examples.

The resin film (I) having the above-mentioned characteristics is excellent in heat resistance, voltage resistance characteristics and surface characteristics.
For example, even when the resin film (I) is heated at 220 ° C. for 10 minutes, shrinkage and softening do not easily occur, and its shape is maintained.
In addition, since the resin film (I) has an appropriate coefficient of static friction, when winding the long resin film (I) into a roll or when drawing the resin film (I) from the roll, When manufacturing a wound-type insulating sheet, the operation can be performed efficiently.

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

  The dielectric film made of the resin film (I) was obtained by cutting the resin film (I) into a predetermined size, or the surface of the resin film (I) was subjected to surface treatment such as corona treatment or plasma treatment. After that, those cut into a predetermined size and the like can be mentioned.

[Other insulating layers]
The other insulating layer which comprises the insulating sheet of this invention can be used combining the material conventionally known as an insulating sheet.
The other insulating layer which comprises an insulating sheet will not be specifically limited if it consists of dielectrics, For example, an aramid paper, a polyethylene terephthalate film, a polyethylene naphthalate film etc. are mentioned.

As other insulating layers can be formed because a thin insulating layer excellent in adhesion to a dielectric film can be formed efficiently, and an insulating sheet smaller and superior in durability can be manufactured. Aramid paper is preferred.
When using an aramid paper as another insulating layer, the method of laminating with the aramid paper is not particularly limited, and a method of modifying the dielectric film surface by corona treatment, plasma treatment, etc. and then laminating, and using an adhesive It is possible to appropriately use a method of laminating and the like.
The other insulating layers may be single-layered or multi-layered.

〔Insulating sheet〕
The insulating sheet of the present invention has a layer comprising the dielectric film.
In the insulating sheet of the present invention, the dielectric film may be made of the resin film (I), and the structure is not particularly limited.

As the insulating sheet of the present invention, a laminated type 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 Laid-Open No. 2006-321183); A laminated type insulation sheet (International Publication No. 2010/150669, JP-A 2013-223962), etc., in which a bonding surface of a body film and another insulating layer is directly thermally bonded.
The manufacturing method of these insulation sheets is not specifically limited, A conventionally well-known method can be utilized.

The insulating sheet of the present invention has, as a dielectric film, a resin film excellent in heat resistance, voltage resistance characteristics, and surface characteristics.
Therefore, the insulation sheet of the present invention is excellent in heat resistance and durability even if it is small, and defective products are unlikely to occur even when manufactured on an industrial scale.
The insulating sheet of the present invention is used for insulating materials of transformers and electric / electronic devices, drive motors for automobiles, industrial motors, wind power generators, etc., taking advantage of its characteristics, and in particular, insulating sheets for drive motors for automobiles Are preferably used.

  Hereinafter, the present invention will be described in more detail by way of examples and comparative examples. The present invention is not limited to these examples. In the following, "parts" and "%" are by weight unless otherwise specified.

The measurement of various physical properties was performed according to the following method.
(1) Molecular weight (weight-average molecular weight and number-average molecular weight) of dicyclopentadiene ring-opened polymer
The molecular weight of the dicyclopentadiene ring-opened polymer was measured by gel permeation chromatography (GPC) using tetrahydrofuran as a solvent, and determined as a standard polystyrene conversion value.
It measured at 40 degreeC, using system HLC-8320 (made by Tosoh Corp.) as a measuring apparatus, and using H type column (made by Tosoh Corp.) as a column.

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

(3) Ratio of racemo-dyad of dicyclopentadiene ring-opened polymer hydrogenated substance Mixed solvent of 1,3,5-trichlorobenzene-d3 / orthodichlorobenzene-d4 (volume ratio: 2/1) as a solvent Inverse gated decoupling method is applied, ¹³ C-NMR measurement is performed at 200 ° C., 43.35 ppm signal derived from meso dyad and racemo dyad with reference to the 127.5 ppm peak of ortho-dichlorobenzene-d 4 as a reference shift Based on the intensity ratio of the 43.43 ppm signal derived from, the ratio of racemo dyad of dicyclopentadiene ring-opened polymer hydrogenated substance was determined.

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

(5) Thermal Shrinkage 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. At this time, each side of the square was made to coincide with the flow direction (MD direction) and the width direction (TD direction) at the time of resin film production.
The obtained measurement sample was heated at 200 ° C. for 10 minutes using an oven, and the amount of change in length in the MD direction and the TD direction before and after heating was examined to calculate the thermal contraction rate of the resin film. The thermal contraction rate is an average value in the MD direction and the TD direction.

(6) Surface roughness of resin film (surface characteristics)
The surface roughness was measured at any part of the obtained resin film using a laser microscope (VK-9700, manufactured by KEYENCE CORPORATION).

(7) Dielectric breakdown voltage of resin film (withstand voltage characteristics)
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 whose inside is replaced with nitrogen, 154.5 parts of cyclohexane and 42.8 parts of a cyclohexane solution (concentration 70%) of dicyclopentadiene (end body content 99% or more) (30 as the amount of dicyclopentadiene) Part), 1.9 parts of 1-hexene were added and the whole volume was heated to 53 ° C. with stirring.
On the other hand, 0.061 part of diethylaluminum ethoxide / n-hexane solution (19% concentration) is added to a solution of 0.014 part of tetrachlorotungsten phenylimide (tetrahydrofuran) complex dissolved in 0.70 part of toluene. Stir for 10 minutes to prepare a catalyst solution.
While stirring the contents of the reaction vessel, this catalyst solution was added into the reactor to start the ring-opening polymerization reaction, and then the ring-opening polymerization reaction was performed for 4 hours while maintaining the total volume at 53 ° C. Next, 0.037 parts of 1,2-ethanediol as a terminator was added to the reaction vessel, the whole volume was heated to 60 ° C., and the polymerization reaction was stopped by stirring for 1 hour.
The number average molecular weight (Mn) and weight average molecular weight (Mw) of the dicyclopentadiene ring-opened polymer in the obtained reaction solution are 8,750 and 28,100 respectively, and the molecular weight distribution (Mw / Mn) is It was 3.21.

To the reaction solution was added 1 part of a hydrotalcite-like compound (Kyowa Chemical Industry Co., Ltd., Kyoward (registered trademark) 2000) as an adsorbent, and the mixture was heated to 60 ° C. and stirred for 1 hour. After adding 0.4 parts of a filter aid (manufactured by Showa Kagaku Kogyo Co., Ltd., Radiolite (registered trademark) # 1500) to this, using a PP pleated cartridge filter (manufactured by ADVANTEC Toyo Corp., TCP-HX), 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-opened polymer solution (30 parts of polymer) after filtration, and the hydrogen pressure is 6 MPa, 180 ° C. The hydrogenation reaction was performed for 4 hours. In the obtained hydrogenation reaction solution, a polymer was deposited to form a slurry solution.
The slurry solution was centrifuged to separate the dicyclopentadiene ring-opened polymer hydrogenated substance and the solution, and the dicyclopentadiene ring-opened polymer hydrogenated substance was collected by filtration. Then, the resultant was dried under reduced pressure at 60 ° C. for 24 hours to obtain 28.5 parts of crystalline dicyclopentadiene ring-opened polymer hydrogenated substance.
The hydrogenation rate of the dicyclopentadiene ring-opened polymer hydrogenated substance was 99% or more, the melting point (Tm) was 262 ° C., and the ratio of racemo dyad was 89%.

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

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

Production Example 3
A film with a thickness of 150 μm and a width of 120 mm, using a resin pellet obtained in Production Example 2, in a hot melt extrusion film molding machine (Measuring Extruder Type Me-20 / 2800 V3 manufactured by Optical Control Systems, Inc.) equipped with a T-die The resulting unstretched film was rolled up 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: 30 rpm

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

Example 2
In Example 1, the stretching was carried out by changing the stretching ratio to 3.0 times × 3.0 times and the stretching speed to 300 mm / min, and further changing the heating temperature to 210 ° C. to carry out the heat treatment. In the same manner as in Example 1, a resin film for a dielectric film was obtained, and various measurements were performed on the obtained resin film for a dielectric film. The measurement results are shown in Table 1.

[Example 3]
The resin film for a dielectric film is produced in the same manner as in Example 1 except that in Example 1, the drawing temperature is changed to 130 ° C., and the heating temperature is changed to 150 ° C., and the heat treatment is performed. Various measurements were performed on the obtained resin film for a dielectric film. The measurement results are shown in Table 1.

Example 4
A resin film for a dielectric film is obtained in the same manner as in Example 1 except that the heat treatment is performed by changing the heating time to 5 minutes in Example 1, and various kinds of resin films for a dielectric film obtained are obtained. It measured. The measurement results are shown in Table 1.

[Example 5]
Example 1 except that the stretching was carried out by changing the draw ratio to 1.5 × 1.5 times in Example 1, and heating was carried out by changing the heating temperature to 230 ° C. and the heating time to 100 minutes. A resin film for a dielectric film was obtained in the same manner as 1 and various measurements were performed on the obtained resin film for a dielectric film. The measurement results are shown in Table 1.

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

Comparative Example 2
A resin film was obtained in the same manner as in Example 1 except that the drawing was carried out by changing the drawing ratio to 1.1 times x 1.1 times in Example 1, and various measurements were made on the obtained resin film. Did. The measurement results are shown in Table 1.
In this resin film, the crystallization did not proceed sufficiently, and the softening point was too low. For this reason, the thermal contraction rate could not be measured.

Comparative Example 3
A resin film was obtained in the same manner as in Example 1 except that the drawing process was performed by changing the drawing speed to 80 mm / min in Example 1, and various measurements were performed on the obtained resin film. The measurement results are shown in Table 1.
In this resin film, the crystallization did not proceed sufficiently, and the softening point was too low. For this reason, the thermal contraction rate could not be measured.

Comparative Example 4
A resin film was obtained in the same manner as in Example 1 except that the heating process was performed by changing the heating temperature to 250 ° C. in Example 1, and various measurements were performed on the obtained resin film. The measurement results are shown in Table 1.

Comparative Example 5
A resin film was obtained in the same manner as in Example 1 except that the heating process was performed by changing the heating temperature to 140 ° C. in Example 1, and various measurements were performed on the obtained resin film. The measurement results are shown in Table 1.

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

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

Table 1 shows the following.
The resin films obtained in Examples 1 to 5 are excellent in heat resistance, voltage resistance characteristics, and surface characteristics.
On the other hand, the resin films obtained in Comparative Examples 1 and 4 have a large heat shrinkage rate and are inferior in heat resistance.
The resin films obtained in Comparative Examples 2 and 3 have low softening points, 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 withstand voltage characteristics.

Claims (1)

A method of manufacturing an insulating sheet having a layer comprising a dielectric film, the method comprising:
The dielectric film is
The unstretched film formed from crystalline dicyclopentadiene ring-opened polymer hydrogenated substance is stretched at a temperature of 95 to 135 ° C., a stretch ratio of 1.5 to 10 times, and a stretch rate of 100 to 30,000 mm / min. After the drawing treatment under the conditions of (1) , the heating temperature is 150 to 240.degree. C., and the heating time is 3 to 600 minutes .
Thermal contraction rate 0.01 to 5.0% when heated at a softening point of 250 to 320 ° C. and 200 ° C. for 10 minutes,
A method for producing 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.