JP2013188924A - Combined sealing body - Google Patents

Abstract

Disclosed is a composite sealing body in which different types of conductive plastics are firmly bonded via an adhesive and have high solvent resistance.
A first conductive layer formed of a cured product of a photocurable composition including a photocurable resin and a first conductive filler, and a crystallinity including a crystalline resin and a second conductive filler. A composite encapsulant is formed by integrating the second conductive layer formed of the resin composition with the adhesive layer formed of the acid-modified olefin resin. The photocurable resin includes a trifunctional or higher polyfunctional vinyl compound and a monofunctional and / or bifunctional vinyl compound. The bifunctional vinyl compound may contain a chain aliphatic bifunctional (meth) acrylate. The bifunctional vinyl compound may further contain a ring-containing bifunctional (meth) acrylate having an aliphatic ring and / or an aromatic ring. The polyfunctional vinyl compound may be a 3-6 functional (meth) acrylate.
[Selection figure] None

Description

  The present invention relates to a composite encapsulant used for an electric double layer capacitor, a lithium ion battery, an electronic component, a semiconductor element, and the like.

  Conventionally, inorganic materials such as metals and glass have been known as materials having solvent resistance, and when encapsulating a solvent, it has been a general technique to encapsulate using an inorganic material. On the other hand, in the case of liquids, there has also been known a technique of encapsulating a content containing a solvent with a soft packaging material formed of plastic and sealing it by heat sealing. However, many solvents swell or dissolve plastic materials, and plastic materials cannot be used for certain solvents. Examples of the solvent for swelling or dissolving the plastic include an electrolyte solution for a lithium ion battery using a polar solvent having high solubility in plastics such as ethylene carbonate and propylene carbonate.

  The current mainstream lithium ion battery is a single battery layer in which an electrolyte layer containing an electrolyte solution is interposed between a positive electrode active material layer and a negative electrode active material layer, and a current collector is laminated on the positive electrode active material layer and the negative electrode active material layer. Further, a plurality of layers are stacked. The lithium ion battery having such a structure includes a general-purpose battery (non-bipolar battery) in which a current collector is stacked on each of a positive electrode active material layer and a negative electrode active material layer, and single battery layers are stacked in parallel. A bipolar type (bipolar) battery in which a positive electrode and a negative electrode are respectively stacked on both surfaces of a current collector and single cell layers are stacked in series is included. In any type, the current collector is required to have conductivity, so that metal foil has been mainly used in the past. However, in recent years, with the demand for reduction in weight and size of lithium ion batteries, plastic ( A conductive film formed of a polymer or resin) and a conductive filler has been proposed as a current collector.

  However, in order to reduce the thickness of the conductive film, it is necessary to use a soft elastomer or the like as a resin component, but a soft resin such as an elastomer or an amorphous resin has low solvent resistance. Furthermore, in a current collector formed of a plastic containing a conductive filler, it is necessary to reduce the proportion of the conductive filler in order to reduce the thickness, and it is difficult to reduce the thickness while maintaining conductivity.

Japanese Patent Laid-Open No. 2010-170833 (Patent Document 1) has a structure including one or more layers having a resin and a conductive material, and a crystalline resin having a melting point of 120 ° C. or higher is used as the resin. A current collector for a bipolar secondary battery to be used is disclosed. This document describes that the volume resistivity in the thickness direction (film thickness direction) of the current collector is 10 ² Ω or less, preferably 10 ² to 10 ⁻⁵ Ω. Furthermore, in the examples, pellets were prepared by adding 10% by weight ketjen black to a crystalline resin such as polypropylene, and then the pellets were kneaded and rolled with a rolling mill to produce a current collecting sheet having a thickness of 50 μm. doing. The electrical resistance in the thickness direction of the obtained current collecting sheet is 10 to 100Ω (2000 to 20000Ω · cm in terms of volume resistivity per 1 cm thickness), and has chemical resistance, oxygen barrier property, and heat press resistance. It is described that it is good and useful as a current collector for a secondary battery such as a lithium ion battery.

  However, this current collector has low solvent resistance. Furthermore, since the thin film is manufactured by the kneading / rolling process, the content of the conductive filler is limited to a small amount and the conductivity is low.

  Furthermore, in a lithium ion battery, it is necessary to be sealed so that the electrolyte solution does not leak, and usually, the ends of the opposing current collectors are sealed with an adhesive (sealant).

  For example, Japanese Patent Laid-Open No. 2007-250449 (Patent Document 2) discloses a seal on a current collector so as to surround a unit cell in which a positive electrode active material layer, an electrolyte layer, and a negative electrode active material layer are laminated in this order. A bipolar secondary battery in which members are arranged is disclosed. In this document, as a current collector, a metal foil, a metal plating material, a thermoformed body of a paste containing a binder (resin) such as an epoxy resin, the main component of which is metal powder, and the like are described. Further, examples of the sealing member include polyolefin resins and thermosetting resins, and it is described that polypropylene, polyethylene, and epoxy resins are preferable.

  In such a sealing member (adhesive), in order to prevent the electrolyte solution from leaking, in addition to the adhesive property for firmly adhering to the current collector and sealing the electrolyte solution, Solvent resistance is also required.

  On the other hand, Japanese Patent Laid-Open No. 2001-76689 (Patent Document 3) seals a thermoadhesive resin layer on the inner surface of an outer bag for preventing leakage of an electrolytic solution and a lead-out terminal formed of a metal foil. Therefore, after forming a thermosetting resin layer as a base layer on a metal foil, an intermediate layer in which a thermocompression-bonded acid-modified polyolefin resin is interposed between the thermosetting resin layer and the thermoadhesive resin layer is provided. A lithium secondary battery is disclosed. In this document, an olefin resin layer such as polypropylene is described as the thermoadhesive resin layer, and an epoxy resin layer and a urethane resin layer are described as the thermosetting resin layer. Furthermore, as an acid-modified polyolefin resin, an acid-modified polypropylene resin obtained by graft polymerization of maleic anhydride is described, and it is described that a carboxyl group forms a covalent bond with a hydroxyl group or an amino group of a thermosetting resin. . In the examples, the epoxy resin was cured at 60 ° C. for 1 hour, the acid-modified polypropylene film was thermocompression bonded, and further cured at 80 ° C. for 3 hours.

  However, the intermediate layer contains no conductive filler and has low solvent resistance.

JP 2010-170833 A (claims, paragraph [0088], examples) JP 2007-250449 A (Claim 1, paragraphs [0028] to [0031], [0068] to [0070]) JP 2001-76689 A (Claims, paragraphs [0015], [0020] to [0024], Examples)

  Accordingly, an object of the present invention is to firmly bond different types of conductive plastics (conductive plastic film containing a photo-curable resin and conductive plastic film containing a crystalline resin) via an adhesive, and solvent resistance. The object is to provide a composite encapsulant having a high value.

  Another object of the present invention is to provide a composite encapsulant that is stable against polar solvents (such as aprotic polar solvents) such as alkylene carbonate, has high solvent resistance, and low solvent permeability. .

  Yet another object of the present invention is that a conductive plastic film having high electrical conductivity and thermal conductivity, excellent in mechanical properties such as flexibility, even when thin and lightweight, is firmly bonded, and is solvent resistant. It is in providing the composite sealing body with high property.

  Another object of the present invention is to provide a composite encapsulant in which different types of conductive plastic films are firmly bonded by a simple method.

  As a result of intensive studies to achieve the above-mentioned problems, the present inventor has a first conductive layer formed of a cured product of a photocurable composition containing a specific photocurable resin and a first conductive filler, and The second conductive layer formed of the crystalline resin composition containing the crystalline resin and the second conductive filler is connected to the adhesive layer (adhesive or sealant) formed of the acid-modified olefin resin. As a result of the integration, it was found that different types of conductive plastics (especially different types of plastic films) can be firmly bonded via an adhesive and solvent resistance can be improved, and the present invention has been completed.

  That is, the composite encapsulant of the present invention includes a first conductive layer formed of a cured product of a photocurable composition containing a photocurable resin and a first conductive filler, a crystalline resin, and a second resin. A composite encapsulant integrated with a second conductive layer formed of a crystalline resin composition containing a conductive filler via an adhesive layer formed of an acid-modified olefin resin, the photocuring The functional resin contains a trifunctional or higher polyfunctional vinyl compound and a monofunctional and / or bifunctional vinyl compound. The bifunctional vinyl compound may contain a chain aliphatic bifunctional (meth) acrylate. The bifunctional vinyl compound may further contain a ring-containing bifunctional (meth) acrylate having an aliphatic ring and / or an aromatic ring. The polyfunctional vinyl compound may be a 3-6 functional (meth) acrylate.

  The crystalline resin may be a polypropylene resin. The first and second conductive fillers may be conductive carbon black. The ratio (weight ratio) between the crystalline resin and the second conductive filler may be about the former / the latter = 90/10 to 55/45. The average thickness of the first conductive layer may be about 3 to 50 μm, and the average thickness of the second conductive layer may be about 15 to 100 μm. The average thickness ratio between the first conductive layer and the second conductive layer may be about 1st conductive layer / second conductive layer = 1/1 to 1/20.

  The acid-modified olefin resin may be a maleic anhydride graft copolymer. The acid-modified olefin resin may have a melting point of about 120 to 150 ° C.

  In the composite encapsulant of the present invention, the same conductive layer as the second conductive layer is further stacked on the first conductive layer, and the same conductive layer as the first conductive layer is further stacked on the second conductive layer. May be.

  In the present specification, acryloyl group and methacryloyl group are collectively referred to as (meth) acryloyl group, and acrylate and methacrylate are collectively referred to as (meth) acrylate.

  In this invention, the 1st conductive layer formed with the hardened | cured material of the photocurable composition containing specific photocurable resin and a 1st conductive filler, crystalline resin, and a 2nd conductive filler are included. Since the second conductive layer formed of the crystalline resin composition is integrated with the adhesive layer formed of the acid-modified olefin resin, the conductive plastic film containing the photocurable resin and the crystal The conductive plastic film containing a conductive resin can be firmly bonded via an adhesive, and the solvent resistance can be improved. In particular, it is stable with respect to polar solvents (such as aprotic polar solvents) such as alkylene carbonates used for lithium ion batteries, and has high solvent resistance and low solvent permeability. Further, when a carbon-based conductive filler such as conductive carbon black is used, the conductive layer can be filled with the carbon-based conductive filler at a high density. Therefore, even if it is thin and lightweight, a conductive plastic film having high electrical conductivity and thermal conductivity and excellent mechanical properties such as flexibility can be firmly bonded, and solvent resistance can be improved. Furthermore, different types of conductive plastic films can be firmly bonded by a simple method by thermocompression bonding.

[Composite encapsulant]
The composite encapsulant of the present invention includes a first conductive layer formed of a cured product of a photocurable composition containing a photocurable resin and a first conductive filler, a crystalline resin, and a second conductive property. A composite encapsulant in which a second conductive layer formed of a crystalline resin composition containing a filler is integrated through an adhesive layer formed of an acid-modified olefin resin.

(First conductive layer)
The 1st conductive layer is formed with the hardened | cured material of the photocurable composition containing photocurable resin and a 1st conductive filler.

(A) Photocurable resin The photocurable resin contains a trifunctional or higher polyfunctional vinyl compound and a monofunctional and / or bifunctional vinyl compound.

(A) Polyfunctional vinyl compound As the polyfunctional vinyl compound, there are 3 or more (for example, about 3 to 8) polymerizable groups (for example, α, β- such as vinyl group and (meth) acryloyl group) in the molecule. It is only necessary to have an (ethylenically unsaturated bond), and specifically, a polyfunctional (meth) acrylate having 3 or more (meth) acryloyl groups is widely used.

As polyfunctional (meth) acrylate, esterified product of polyhydric alcohol and (meth) acrylic acid, for example, glycerin tri (meth) acrylate, trimethylolpropane tri (meth) acrylate, trimethylolethane tri (meth) acrylate, Examples include pentaerythritol tri (meth) acrylate; ditrimethylolpropane tetra (meth) acrylate, pentaerythritol tetra (meth) acrylate; dipentaerythritol penta (meth) acrylate; dipentaerythritol hexa (meth) acrylate, and the like. Further, in these polyfunctional (meth) acrylates, the polyhydric alcohol may be an adduct of alkylene oxide (for example, C _2-4 alkylene oxide such as ethylene oxide or propylene oxide). The average addition mole number of alkylene oxide can be selected from the range of about 0-30 mol (especially 1-10 mol), for example. These polyfunctional (meth) acrylates can be used alone or in combination of two or more.

  Among these polyfunctional vinyl compounds, 3-6 functional (meth) acrylates such as trimethylolpropane tri (meth) acrylate, pentaerythritol tri (meth) acrylate and pentaerythritol tetra (meth) acrylate are preferable, and pentaerythritol tris. 3 to 4 functional (meth) acrylates such as (meth) acrylate are widely used. Furthermore, the polyfunctional vinyl compound is preferably a polyfunctional vinyl compound that has not been modified with an amine (polyfunctional vinyl compound to which no amine has been added by Michael addition or the like).

(B) Monofunctional and / or bifunctional vinyl compound The monofunctional and / or bifunctional vinyl compound has one or two polymerizable groups (α, β-ethylenically unsaturated bond) in the molecule. Specifically, it may be an aromatic vinyl compound such as styrene or divinylbenzene, but from the viewpoint of photopolymerization and the like, monofunctional or 2 having one or two (meth) acryloyl groups Functional (meth) acrylates are widely used.

(B1) Monofunctional vinyl compound Examples of the monofunctional vinyl compound include (meth) acrylic acid; methyl (meth) acrylate, ethyl (meth) acrylate, propyl (meth) acrylate, butyl (meth) acrylate, isobutyl ( (Meth) acrylate, sec-butyl (meth) acrylate, t-butyl (meth) acrylate, hexyl (meth) acrylate, octyl (meth) acrylate, isooctyl (meth) acrylate, 2-ethylhexyl (meth) acrylate, decyl (meth) acrylate, lauryl (meth) acrylate, _{C 1-24} alkyl (meth) such as stearyl (meth) acrylate acrylate; cyclohexyl (meth) cycloalkyl (meth) acrylates such as acrylate; dicyclopentanyl ( ) Acrylate, dicyclopentenyl (meth) acrylate, dicyclopentenyloxyethyl (meth) acrylate, bornyl (meth) acrylate, isobornyl (meth) acrylate, tricyclodecanyl (meth) acrylate, etc. ) Acrylate; aryl (meth) acrylates such as phenyl (meth) acrylate and nonylphenyl (meth) acrylate; aralkyl (meth) acrylates such as benzyl (meth) acrylate; hydroxyethyl (meth) acrylate, hydroxypropyl (meth) acrylate, hydroxy _{C 2-10} alkyl (meth) acrylate or _{C 2-10} alkanediol mono (meth) acrylates such as hydroxybutyl (meth) acrylate; trifluoroethyl (meth Alkoxyalkyl (meth) acrylates such as methoxyethyl (meth) acrylate; acrylate, tetrafluoropropyl (meth) acrylate, fluoroalkyl C _1-10 alkyl (meth) acrylates such as hexafluoroisopropyl (meth) acrylate and phenoxyethyl (meth) Aryloxyalkyl (meth) acrylates such as acrylate and phenoxypropyl (meth) acrylate; aryloxy (poly) such as phenyl carbitol (meth) acrylate, nonylphenyl carbitol (meth) acrylate, and nonylphenoxypolyethylene glycol (meth) acrylate Alkoxyalkyl (meth) acrylates; Polyalkylene glycol mono (meth) ) Acrylate; alkane polyol mono (meth) acrylate such as glycerin mono (meth) acrylate; 2-dimethylaminoethyl (meth) acrylate, 2-diethylaminoethyl (meth) acrylate, 2-t-butylaminoethyl (meth) acrylate, etc. (Meth) acrylate having an amino group or a substituted amino group; glycidyl (meth) acrylate; vinylpyrrolidone and the like.

(B2) Bifunctional vinyl compound Examples of the bifunctional vinyl compound include allyl (meth) acrylate; ethylene glycol di (meth) acrylate, propylene glycol di (meth) acrylate, and 1,3-propanediol di (meth). Alkanediol di (meth) acrylates such as acrylate, 1,4-butanediol di (meth) acrylate, neopentyl glycol di (meth) acrylate, 1,6-hexanediol di (meth) acrylate; glycerin di (meth) acrylate Alkane polyol di (meth) acrylate such as: Diethylene glycol di (meth) acrylate, triethylene glycol di (meth) acrylate, polyethylene glycol di (meth) acrylate, dipropylene glycol di (meth) acrylate Polyalkylene glycol di (meth) acrylates such as polypropylene glycol di (meth) acrylate; 2,2-bis (4- (meth) acryloxyethoxyphenyl) propane, 2,2-bis (4- (meth) acrylic Di (meta) of C _2-4 alkylene oxide adducts of bisphenols (bisphenol A, bisphenol S, etc.) such as loxydiethoxyphenyl) propane and 2,2-bis (4- (meth) acryloxypolyethoxyphenyl) propane ) Acrylates; di (meth) acrylates of alkane polyol partial esters such as pentaerythritol fatty acid esters; and bridged cyclic di (meth) acrylates such as tricyclodecane dimethanol di (meth) acrylate and adamantane di (meth) acrylate Exemplification it can.

  Furthermore, as a bifunctional vinyl compound, for example, epoxy di (meth) acrylate (such as bisphenol A type epoxy di (meth) acrylate), polyester di (meth) acrylate (for example, aliphatic polyester type di (meth) acrylate, aromatic Examples include oligomers or resins such as polyester-type di (meth) acrylate), (poly) urethane di (meth) acrylate (polyester-type urethane di (meth) acrylate, polyether-type urethane di (meth) acrylate, etc.), and silicone (meth) acrylate. it can.

  These vinyl compounds can be used alone or in combination of two or more. Among these vinyl compounds, a bifunctional (meth) acrylate is preferable from the viewpoint of reactivity and solvent resistance, and a chain aliphatic having a chain aliphatic skeleton from the viewpoint of improving the flexibility of the cured product. Bifunctional (meth) acrylates including bifunctional (meth) acrylates are particularly preferred.

(B2-1) Chain aliphatic bifunctional (meth) acrylate The chain aliphatic bifunctional (meth) acrylate may have an alkylene chain. For example, 1,4-butanediol di (meth) C _2-12 alkanediol di (meth) acrylate such as acrylate, neopentyl glycol di (meth) acrylate, 1,6-hexanediol di (meth) acrylate; di (meth) acrylate of alkane polyol fatty acid ester; aliphatic polyester Type di (meth) acrylate; aliphatic polyester type urethane di (meth) acrylate and the like. Moreover, the chain | strand-shaped aliphatic skeleton may be introduce | transduced into the (meth) acrylate which has an aliphatic ring and / or an aromatic ring. Furthermore, the number of carbon atoms of the alkylene chain constituting the chain aliphatic skeleton can be selected from a range of, for example, about 3 to 20, but is preferably 4 to 12, for example, from the viewpoint of the balance between flexibility and solvent resistance. Is preferably 4 to 10, more preferably about 4 to 8 (particularly 5 to 8). These chain aliphatic bifunctional (meth) acrylates can be used alone or in combination of two or more.

  Further, the chain aliphatic bifunctional (meth) acrylate particularly preferably contains a lactone-derived unit and / or an aliphatic polyester unit.

Examples of the lactone include C ₃ such as γ-butyrolactone (GBL), γ-valerolactone, δ-valerolactone, β-methyl-δ-valerolactone, γ-caprolactone, and enanthlactone (7-hydroxyheptanoic acid lactone). _{And -10} lactone. These lactones can be used alone or in combination of two or more. Of these lactones, C _4-8 lactones (particularly C _5-8 lactones) such as valerolactone and caprolactone are preferred.

Examples of the aliphatic polyester include aliphatic dicarboxylic acids or anhydrides thereof (C _4-20 alkanedicarboxylic acids such as succinic acid, succinic anhydride, adipic acid, azelaic acid, and sebacic acid) and aliphatic diols (ethylene glycol). Reaction products with C _2-10 alkanediols such as propylene glycol and tetramethylene ether glycol), reaction products obtained by ring-opening addition polymerization of the lactone with respect to the initiator, and the like. The degree of polymerization of the polyester unit can be appropriately selected from a range of, for example, about 2 to 100, and may be, for example, 3 to 90, preferably 5 to 80, and more preferably about 10 to 70.

Examples of chain aliphatic bifunctional (meth) acrylates containing lactone-derived units and / or aliphatic polyester units include aliphatic polyester _diesters having polyester units obtained by ring-opening polymerization of C _5-8 lactones such as caprolactone. (Meth) acrylate, urethane di (meth) acrylate having the polyester unit, epoxy di (meth) acrylate having the polyester unit, and the like can be used.

  Furthermore, the polyisocyanate unit of the polyester type urethane di (meth) acrylate may be any of aliphatic polyisocyanate, alicyclic polyisocyanate, and aromatic polyisocyanate, and aliphatic polyisocyanate such as hexamethylene diisocyanate is widely used. . The epoxy di (meth) acrylate having a polyester unit may be a bisphenol-type epoxy (meth) acrylate such as bisphenol A.

(B2-2) Ring-containing bifunctional (meth) acrylate A monofunctional and / or bifunctional vinyl compound, in addition to the vinyl compound having a chain aliphatic skeleton, further improves solvent resistance. A (meth) acrylate having an aliphatic ring and / or an aromatic ring (ring-containing (meth) acrylate) may be included.

The ring-containing bifunctional (meth) acrylate may have an aliphatic ring and / or an aromatic ring in the molecule. For example, tricyclodecane dimethanol di (meth) acrylate, adamantane di (meth) acrylate C _6-20 (especially C _8-12 ) bridged 2-4 cyclic di (meth) acrylate; 2,2-bis (4- (meth) acryloxyethoxyphenyl) propane, 2,2-bis ( 4- (meth) acryloxypropoxyphenyl) propane, 2,2-bis (4- (meth) acryloxydiethoxyphenyl) propane, 2,2-bis (4- (meth) acryloxypolyethoxyphenyl) propane, etc. bisphenols (bisphenol a, S, _{etc.) -C 2-4} alkylene oxide adducts [average addition mole number of alkylene oxide 0-30 Di (meth) acrylates, oligomers [aromatic epoxy (meth) acrylates such as bisphenol A type epoxy (meth) acrylates, novolac type epoxy (meth) acrylates, etc.]] and the like. . These bifunctional (meth) acrylates can be used alone or in combination of two or more.

Among these ring-containing bifunctional (meth) acrylates, polycyclic alicyclic rings such as tricyclodecane dimethanol di (meth) acrylate and adamantane di (meth) acrylate are used because of the high solvent resistance and strength of the cured product. Di (meth) acrylate having a bisphenol skeleton such as di (meth) acrylate having a group skeleton, 2,2-bis (4- (meth) acryloxyethoxyphenyl) propane, bisphenol A type epoxy (meth) acrylate, Particularly preferred are di (meth) acrylates having a C _8-12 bridged 2-4 cyclic alicyclic skeleton such as tricyclodecane dimethanol di (meth) acrylate.

  The proportion of the ring-containing bifunctional (meth) acrylate can be appropriately selected from the range of about 0 to 500 parts by weight with respect to 100 parts by weight of the chain aliphatic bifunctional (meth) acrylate according to the target viscoelasticity. 5 to 200 parts by weight, preferably 10 to 100 parts by weight (for example, 20 to 80 parts by weight), more preferably about 30 to 60 parts by weight (particularly 40 to 50 parts by weight). In the present invention, flexibility can be improved while maintaining solvent resistance by combining the chain aliphatic bifunctional (meth) acrylate and the ring-containing bifunctional (meth) acrylate at such a ratio.

  The proportion of the monofunctional and / or bifunctional vinyl compound can be selected from the range of about 1 to 1000 parts by weight with respect to 100 parts by weight of the polyfunctional vinyl compound, for example, 5 to 500 parts by weight, preferably 10 to 10 parts by weight. About 300 parts by weight.

  In the present invention, the monofunctional and / or bifunctional vinyl compound can be selected from the above range depending on the type of the monofunctional and / or bifunctional vinyl compound. For example, the monofunctional and / or bifunctional vinyl compound is a chain aliphatic bifunctional (meth) acrylate and In the case of a combination with a ring-containing bifunctional (meth) acrylate, the proportion of the monofunctional and / or bifunctional vinyl compound is, for example, 30 to 500 parts by weight, preferably 100 parts by weight of the polyfunctional vinyl compound. Is about 50 to 300 parts by weight, more preferably about 100 to 200 parts by weight (particularly 120 to 150 parts by weight).

  When the monofunctional and / or bifunctional vinyl compound is a chain aliphatic bifunctional (meth) acrylate, the ratio of the monofunctional and / or bifunctional vinyl compound is 100 parts by weight of the polyfunctional vinyl compound. On the other hand, it is about 1-100 weight part, for example, Preferably it is 5-50 weight part, More preferably, it is about 10-40 weight part (especially 20-30 weight part).

(B) First conductive filler Examples of the first conductive filler include carbon materials (for example, artificial graphite, expanded graphite, natural graphite, coke, conductive carbon black, carbon fiber, etc.), simple metals or alloys. (For example, iron, copper, magnesium, aluminum, gold, platinum, zinc, manganese, stainless steel, etc.), ceramics (for example, ferrite, tourmaline, diatomaceous earth, etc.), etc. are mentioned. These conductive fillers can be used alone or in combination of two or more.

  Among these conductive fillers, a carbon-based conductive filler is preferable from the viewpoint of lightness. The carbon-based conductive filler is excellent in light weight as compared with the metal filler, and even if a large amount of filler is blended, the light weight is not greatly impaired.

  Although it is difficult to determine the true specific gravity of carbon-based conductive fillers, especially nano-level particulate fillers, the specific gravity of carbon-based conductive fillers is 2.5 or less, for example, 0.30 to 2.5, preferably Is about 0.45 to 2.0, more preferably about 1.0 to 2.0 (especially 1.4 to 1.9).

  Furthermore, in the present invention, among carbon-based conductive fillers, conductive carbon black is preferable from the viewpoint of conductivity and lightness.

  Examples of the conductive carbon black include furnace black, channel black, gas black, acetylene black, arc black, and ketjen black. These conductive carbon blacks can be selected depending on the application.For example, acetylene black with low oil content may be used to improve flame retardancy, and hollow shell structure ketjen black is used to improve lightness. May be. Of these conductive carbon blacks, furnace black, ketjen black, acetylene black and the like are preferable from the viewpoint of conductivity. Further, the conductive carbon black may be a conductive composite carbon black obtained by combining these conductive carbon blacks.

  Commercially available conductive carbon blacks include ketjen black ("EC600JD", "EC300J", "MBP1853" manufactured by Ketjen Black International Co., Ltd.), acetylene black ("Denka Black HS, manufactured by Denki Kagaku Kogyo Co., Ltd.). −100 ”), furnace carbon black (“ Toka Black # 5500 ”,“ Toka Black # 4300 ”manufactured by Tokai Carbon Co., Ltd.,“ # 3030B ”,“ # 3400B ”manufactured by Mitsubishi Chemical Corporation), etc.) Examples thereof include conductive carbon black having various properties such as cohesiveness.

  Examples of the shape of the first conductive filler include a particulate shape (powder shape), a plate shape (or scale shape), a fiber shape, and an indefinite shape. Of these shapes, particle shapes such as a substantially spherical shape and a polygonal shape are widely used.

  The average primary particle diameter (calculated average particle diameter obtained by observation with a transmission electron microscope) of the first conductive filler (particularly conductive carbon black) can be appropriately selected from a range of about 10 μm or less. 1 μm or less is preferable from the viewpoint of being dispersible, and in addition, for example, from 1 to 1000 nm, preferably from 5 to 100 nm, further from the point of being able to suppress pinholes and tearing when the first conductive layer is thin and thin. Preferably it is about 10-60 nm (especially 10-50 nm).

  In the first conductive layer (conductive molded body), the first conductive filler (particularly conductive carbon black) has such a primary particle size, but the primary particles in the conductive layer are aggregated. It can be estimated that aggregates (aggregates) are further formed. It can be presumed that this aggregate structure is maintained even in the thinned layer, forms a network structure with many contact points between particles, and improves the conductivity of the conductive layer.

The first conductive filler (in particular, conductive carbon black) DBP (dibutyl phthalate) oil absorption amount of (A method of JIS K6221), depending on the application, 10~1000cm ³ / 100g (e.g., 30~500cm ³ / 100 g), and the nitrogen adsorption BET specific surface area is 20 m ² / g or more, preferably 30 m ² / g or more (for example, 30 to 2000 m ² / g), more preferably 100 m ² / g or more (for example, 100 to 1500 m ² / g).

  The ratio of the first conductive filler is from about 1 to 100 parts by weight with respect to 100 parts by weight of the photocurable resin (the total amount of the polyfunctional vinyl compound and the monofunctional and / or bifunctional vinyl compound). For example, it is about 3 to 80 parts by weight, preferably about 5 to 50 parts by weight, more preferably about 10 to 40 parts by weight (particularly 15 to 35 parts by weight), and in particular, the flexibility of the cured product is ensured. To 45 parts by weight or less (particularly about 5 to 40 parts by weight).

(C) Organic solvent The photocurable composition may contain an organic solvent. Examples of the organic solvent include ketones (acetone, methyl ethyl ketone, methyl isobutyl ketone, cyclohexanone, etc.), ethers (dioxane, tetrahydrofuran, etc.), aliphatic hydrocarbons (hexane, etc.), alicyclic hydrocarbons (cyclohexane, etc.) ), Aromatic hydrocarbons (benzene, toluene, xylene, etc.), halogenated carbons (dichloromethane, dichloroethane, etc.), esters (methyl acetate, ethyl acetate, etc.), water, alcohols (ethanol, isopropanol, butanol, cyclo Hexanol, etc.), cellosolves (methyl cellosolve, ethyl cellosolve, etc.), cellosolve acetates, amides (dimethylformamide, dimethylacetamide, etc.) and the like. These organic solvents can be used alone or in combination of two or more. Of these organic solvents, ketones such as methyl ethyl ketone, aromatic hydrocarbons such as toluene, etc. are widely used. For the purpose of improving the properties such as coating properties, monofunctional vinyl compounds such as styrene and other vinyl compounds such as (meth) acrylic acid may be used as the reactive diluent.

  The ratio of the solvent can be selected from a range of about 10 to 1000 parts by weight with respect to 100 parts by weight of the photocurable resin, and for example, 50 to 500 parts by weight, preferably 80 to 300 parts by weight, and more preferably 100 to 200 parts by weight. Part (particularly 120 to 180 parts by weight).

(D) Other Additives The photocurable composition further includes conventional additives such as polymerization initiators (eg, photopolymerization initiators, photosensitizers, etc.), polymers, plasticizers, and other conductive agents. Filler, conductive polymer, stabilizer (heat stabilizer, ultraviolet absorber, light stabilizer, antioxidant, etc.), dispersant, antistatic agent, colorant, lubricant, crystal nucleating agent, flame retardant, flame retardant Auxiliaries, fillers, impact resistance improvers, reinforcing agents, foaming agents, antibacterial agents and the like may be contained. These additives can be used alone or in combination of two or more. The ratio of these additives is, for example, 10 parts by weight or less, preferably 0.01 to 5 parts by weight, more preferably 0.05 to 3 parts, with respect to 100 parts by weight of the total of the photocurable resin and the conductive filler. About 1 part by weight (particularly 0.1 to 2 parts by weight).

  However, the photocurable composition may not substantially contain a polymerization initiator (for example, a photopolymerization initiator, a photosensitizer, a thermal polymerization initiator, etc.) when cured with an electron beam. Furthermore, it is preferable that a photocurable composition does not contain a thermoplastic resin (especially polyphenylene oxide resin) substantially as a resin component from the point of solvent resistance.

(Hardened product of photocurable composition)
The first conductive layer formed of a cured product is obtained by irradiating and curing the photocurable composition as described later, and is −50 under conditions of a temperature rising rate of 5 ° C./min and a frequency of 10 Hz. In the dynamic viscoelasticity test measured from ℃ to 250 ℃, the storage elastic modulus E ′ in the rubbery region is 200 to 2000 MPa, preferably 300 to 1500 MPa, more preferably about 350 to 1200 MPa (particularly 400 to 1000 MPa). is there. In addition, the rubber-like region is substantially flat in the vicinity of 10 ⁶ to 10 ⁷ Pa after passing through a transition region in which the storage elastic modulus-temperature curve greatly decreases as the temperature rises from a glassy region of about 10 ¹⁰ Pa. Means an area to become.

  Since the first conductive layer (cured product) has such a storage elastic modulus E ′, it has an appropriate crosslinking density, is excellent in solvent resistance, and contains a conductive filler to be conductive. Although it is excellent, it has moderate flexibility. In particular, there is a trade-off between the relationship between solvent resistance and flexibility, and the relationship between the improvement in conductivity and the improvement in the above characteristics due to the addition of the conductive filler, and these properties are well balanced. Although the first conductive layer is difficult to adjust, the viscoelasticity of the photocured product is adjusted by adjusting the type and ratio of the resin component, the number of functional groups, the molecular weight (viscosity), the type and blending amount of the conductive filler. By controlling the value within the above range, both characteristics are obtained.

The first conductive layer is excellent in conductivity and may have a volume resistivity of 10 ⁵ Ω · cm or less, for example, 10 ⁴ Ω · cm or less (for example, 0.01 to 10 ⁴ Ω · cm). , Preferably 10 ³ Ω · cm or less (for example, 0.1 to 10 ³ Ω · cm), more preferably 10 ² Ω · cm or less (particularly 10 Ω · cm or less).

  Although the shape of a 1st conductive layer is not specifically limited, Usually, it is a sheet form or a film form. The average thickness of the first conductive layer can be selected from the range of about 1 to 100 μm depending on the application, and is, for example, about 1 to 80 μm, preferably 3 to 50 μm, more preferably 5 to 30 μm (particularly 8 to 20 μm). is there.

  The first conductive layer may be surface-treated in order to improve adhesion, and a conventional surface treatment such as corona discharge treatment, flame treatment, plasma treatment, ozone or ultraviolet irradiation treatment, or an organic solvent is used. The surface treatment may be performed by a cleaning treatment, a chemical treatment using an acid or an alkali, a polishing treatment using polishing paper or sandblasting, or the like.

  The first conductive layer is integrated (adhered) with the second conductive layer through the adhesive layer, but the surface opposite to the side to be bonded to the second conductive layer has mechanical characteristics and the like. Further, other layers may be laminated. The laminated structure with other layers is not limited to a two-layer structure, and may be a multilayer structure of three or more layers.

  The other layer may be formed of glass, ceramic, metal, plastic or the like, but plastic is preferable from the viewpoint of adhesion to a cured product. Examples of the plastic include olefin resins (polyethylene, polypropylene, amorphous polyolefin, etc.), styrene resins (polystyrene, acrylonitrile-styrene copolymers, etc.), polyester resins (polyethylene terephthalate, polybutylene terephthalate, polyethylene naphthalate). Such as polyalkylene arylate resin, polyarylate resin, liquid crystalline polyester, etc., polyamide resin (polyamide 6, polyamide 66, polyamide 12, etc.), vinyl chloride resin (polyvinyl chloride, etc.), polycarbonate resin (bisphenol) A type polycarbonate), polyvinyl alcohol resin, cellulose ester resin, polyimide resin, polysulfone resin, polyphenylene ether resin, poly E double sulfide resins, and fluorine resins. Of these, polypropylene resins such as polypropylene, polyamide resins, polyester resins and the like are preferable from the viewpoint of excellent heat resistance. Further, the plastic may contain the conductive filler. The other layer may be a functional layer (hard coat layer, other conductive layer, antistatic layer, optical layer, etc.).

  In particular, in the present invention, even if it is thin and lightweight, the other layers are the same as the second conductive layer described later from the viewpoint of high conductivity and thermal conductivity and excellent mechanical properties such as flexibility. The conductive layer may be used. When other layers are formed of the same conductive layer as the second conductive layer, a conductive laminated film in which the first conductive layer and the second conductive layer are laminated (a conductive laminated film laminated without an adhesive layer) The composite encapsulant of the present invention may be a composite encapsulant obtained by laminating two or more (especially three or more) conductive laminate films. That is, such conductive laminated films are laminated such that the first conductive layer side and the second conductive layer side are in contact with each other, and the first conductive layer and the second conductive layer that are in contact are bonded to each other. A composite encapsulant in which three or more layers are laminated (adhering three or more conductive laminated films with an adhesive layer interposed between the first conductive layer and the second conductive layer) Composite sealing body) can be produced. Such a composite encapsulant is suitable for a bipolar battery of a lithium ion battery in which a large number of current collectors are stacked, for example.

(Second conductive layer)
The second conductive layer is formed of a crystalline resin composition containing a crystalline resin and a second conductive filler. In the present invention, by integrating the first conductive layer and the second conductive layer through the adhesive layer, even if it is thin and lightweight, the electrical conductivity and thermal conductivity are high, and the machine such as flexibility A composite encapsulant having excellent mechanical properties can be obtained.

(A) Crystalline resin Examples of the crystalline resin include olefin resins (polyethylene resins such as high density polyethylene, polypropylene resins, etc.), styrene resins (syndiotactic polystyrene, etc.), polyacetal resins (polyoxy). Methylene, etc.), polyester resins (polyethylene terephthalate, polybutylene terephthalate, polyalkylene arylates such as polyethylene naphthalate, liquid crystal polyesters, etc.), polyamide resins (aliphatic polyamides, etc.), polyphenylene sulfide resins, polyether ether ketone, fluorine Resin (polytetrafluoroethylene etc.) etc. are mentioned. These crystalline resins can be used alone or in combination of two or more.

  Of these crystalline resins, polypropylene resins, polyamide resins, polyphenylene sulfide resins, polyether ether ketones, etc. are preferred because of their excellent heat resistance and mechanical properties. Solvent resistance, moldability, and lightness are preferred. Polypropylene resins and polyamide resins are particularly preferred from the standpoint of superiority.

(A1) Polypropylene resin The polypropylene resin may be a propylene copolymer (propylene copolymer) as well as a propylene homopolymer (propylene homopolymer). Copolymers include propylene and α-olefins [e.g., ethylene, 1-butene, 2-butene, 1-pentene, 1-hexene, 3-methylpentene, 4-methylpentene, 4-methyl-1-butene, 1 Α-C _2-16 olefins other than propylene such as hexene, 1-octene, 1-nonene, 1-decene, 1-undecene and 1-dodecene (particularly α-C _2-6 olefins such as ethylene and butene), etc. ], For example, propylene-ethylene random copolymer, propylene-butene random copolymer, propylene-ethylene-butene random terpolymer, and the like. In the present invention, from the viewpoints of solvent resistance and heat resistance, it does not substantially contain a copolymerizable unit having a polar group such as maleic acid or (meth) acrylic acid and / or an aromatic vinyl unit such as styrene. Is preferred. Examples of the form of the copolymer include block copolymerization, random copolymerization, and graft copolymerization.

  In the copolymer, the ratio (molar ratio) of propylene and α-olefin (particularly ethylene) is propylene / α-olefin = 90/10 to 100/0, preferably 95/5 to 100/0, more preferably. It is about 99/1 to 100/0. When the proportion of α-olefin is too small, crystallinity is lowered, and solvent resistance and heat resistance are lowered. In the present invention, a homopolymer is preferred.

  The polypropylene resin may be an atactic polymer, but from the viewpoint of improving crystallinity, a structure having stereoregularity such as isotactic and syndiotactic is preferable, and an isotactic polymer is particularly preferable.

  Further, the polypropylene resin may be a polymer using a Ziegler catalyst, but a metallocene resin using a metallocene catalyst from the viewpoint of obtaining a polymer having a low molecular weight tack component and a narrow molecular weight distribution. It is preferable to contain at least (particularly a metallocene copolymer).

  The specific gravity of the polypropylene resin is 1.00 or less (particularly 0.95 or less), for example, 0.80 to 0.95, preferably 0.85 to 0.95, and more preferably 0.87 to 0.93. (Especially about 0.89 to 0.91).

  The melting point of the polypropylene resin (melting peak temperature in the differential scanning calorimeter DSC) can be selected from a range of about 100 to 170 ° C., for example, but is 110 to 170 ° C., preferably 120 to 120 ° C. from the viewpoint of heat resistance. It is about 168 ° C., more preferably about 130 to 166 ° C. (especially 160 to 166 ° C.). In the present specification, the melting point of the polypropylene resin in the crystalline resin is measured in the state of pellets prepared by melting and mixing with a conductive filler.

  The melt flow rate (MFR) of the polypropylene resin is, for example, 0.3 to 60 g / 10 minutes, preferably 0.2 to 20 g / 10 minutes, more preferably 1 to 7 g / 10, according to ASTM D1238. About minutes.

(A2) Polyamide resin Examples of polyamide resins include polyamides obtained by polycondensation of diamine and dicarboxylic acid, polyamides obtained by polycondensation of aminocarboxylic acid, and polyamides obtained by ring-opening polymerization of lactam. And polyamides obtained by polymerizing these monomers in combination.

  Examples of the diamine include trimethylenediamine, tetramethylenediamine, pentamethylenediamine, hexamethylenediamine, 2,2,4-trimethylhexamethylenediamine, 2,4,4-trimethylhexamethylenediamine, octamethylenediamine, and nonamethylene. Aliphatic diamines such as diamines; and alicyclic diamines such as bis (4-aminocyclohexyl) methane and bis (4-amino-3-methylcyclohexyl) methane. In addition, aromatic diamines such as phenylenediamine and metaxylylenediamine may be used in combination. These diamines can be used alone or in combination of two or more.

Examples of the dicarboxylic acid include C _4-20 aliphatic dicarboxylic acids such as glutaric acid, adipic acid, pimelic acid, suberic acid, azelaic acid, sebacic acid, and octadecanedioic acid; dimerized fatty acid (dimer acid); cyclohexane Examples include alicyclic dicarboxylic acids such as -1,4-dicarboxylic acid and cyclohexane-1,3-dicarboxylic acid; aromatic dicarboxylic acids such as phthalic acid, phthalic anhydride, isophthalic acid, terephthalic acid, and naphthalenecarboxylic acid. . These dicarboxylic acids can be used alone or in combination of two or more.

Examples of aminocarboxylic acids include C _4-20 aminocarboxylic acids such as aminoheptanoic acid, aminononanoic acid, and aminoundecanoic acid. Aminocarboxylic acids can be used alone or in combination of two or more. These aminocarboxylic acids can be used alone or in combination of two or more.

Examples of the lactam include C _4-20 lactams such as butyrolactam, bivalolactam, caprolactam, capryllactam, enantolactam, undecanolactam, and dodecalactam. These lactams can be used alone or in combination of two or more.

  Polyamide resins include aliphatic polyamides such as polyamide 46, polyamide 6, polyamide 66, polyamide 610, polyamide 612, polyamide 11 and polyamide 12, aromatic dicarboxylic acids (for example, terephthalic acid and / or isophthalic acid) and aliphatic. Obtained from polyamides obtained from diamines (eg hexamethylenediamine, nonamethylenediamine, etc.), aromatic and aliphatic dicarboxylic acids (eg terephthalic acid and adipic acid) and aliphatic diamines (eg hexamethylenediamine) Examples thereof include polyamide. These polyamide-based resins are not limited to homopolyamide but may be copolyamide. These polyamide resins can be used alone or in combination of two or more.

Of these polyamide-based resins, aliphatic polyamides such as polyamide 46, polyamide 6, polyamide 66, polyamide 610, polyamide 612, polyamide 11, and polyamide 12 are preferable because of high crystallinity and excellent heat resistance. These aliphatic polyamides can be selected depending on the use, and when improving crystallinity such as uses where heat resistance and gas barrier properties are important, aliphatic polyamides having a C _2-12 alkylene chain (particularly polyamide 46). And aliphatic polyamides having a C _3-8 alkylene chain such as polyamide 66). In applications where moldability and solvent resistance are important, aliphatic polyamides having C _8-16 alkylene chains (particularly aliphatic polyamides having C _10-14 alkylene chains such as polyamide 11 and polyamide 12) are preferred.

  The specific gravity of the polyamide resin is 1.05 or less, for example, about 0.80 to 1.04, more preferably about 0.85 to 1.02.

  The melting point of the polyamide-based resin (melting peak temperature in the differential scanning calorimeter DSC) can be selected from a range of about 100 to 250 ° C., for example, but is 140 to 220 ° C., preferably 150 to 150 ° C. from the viewpoint of heat resistance. It is 200 degreeC, More preferably, it is about 160-190 degreeC (especially 170-180 degreeC) grade. In the present specification, the melting point of the polyamide-based resin is measured in the state of pellets prepared by melt mixing with the conductive filler.

  Of these crystalline resins, polypropylene resins are particularly preferred because they are excellent in chemical resistance, gas barrier properties, toughness, and economy in addition to the above-mentioned properties. In particular, when a polypropylene resin is used, the effect of reducing the weight is remarkable. Furthermore, polypropylene resin is more preferably used in applications that require low moisture permeability or water absorption.

(B) Second conductive filler As the second conductive filler, the conductive filler exemplified in the section of the conductive filler (first conductive filler) of the photocurable resin composition can be used. As the second conductive filler, a carbon-based conductive filler is preferable, and conductive carbon black is particularly preferable because a large amount of filler is added to the crystalline resin so that lightness is not greatly impaired. The specific gravity of the second carbon filler is the same as that of the first carbon filler. As the second conductive carbon black, the conductive carbon black exemplified in the section of the first conductive filler can be used.

  The shape, average primary particle size, DBP oil absorption, and specific surface area of the second conductive filler (particularly the second conductive carbon black) are the same as those of the first conductive filler. In particular, by adjusting the average primary particle size of the second conductive layer, pinholes and tearing can be suppressed even if the second conductive layer is thinned by extrusion molding or the like.

  The ratio (weight ratio) between the crystalline resin and the second conductive filler is the former / the latter = 90/10 to 55/45, preferably 85/15 to 55/45, and more preferably 85/15 to It is about 60/40 (particularly 80/20 to 60/40). When the content of the second conductive filler is too small, the volume specific resistance value of the thin second conductive layer is increased. Conversely, when the content is too large, the film moldability and film properties tend to be lowered.

  In addition, when the second conductive filler is a carbon-based conductive filler, a special filler (such as ketjen black) having an internal void or cavity such as a hollow structure or a tube structure has a low apparent density, and therefore the resin composition While the volume is large and the aggregate structure is easily formed with respect to the added weight to the product, the influence of the filler on the kneading and melt extrusion characteristics becomes larger. Therefore, although the true specific gravity of the composition is low and a film having high electrical conductivity can be obtained even with a small addition amount, the upper limit of the addition weight is higher than other carbon-based fillers with a large apparent density because of the workability of the composition. Tend to be low. In addition, a structure having voids or cavities is destroyed by mechanical shearing force such as kneading, extrusion molding, stretching, rolling, etc., compared to a filler having substantially no internal voids or cavities, such as acetylene black. Tend. Therefore, when using the filler which has a space | gap inside, it is necessary to pay attention to the conditions in each process.

  The ratio between the crystalline resin and the second carbon-based conductive filler may be adjusted according to the specific gravity of the carbon-based conductive filler, and although it is difficult to determine the true specific gravity of the nano-level granular carbon black, for example, In the case of a filler (for example, acetylene black) having a specific gravity of 2.0 to 1.7 (particularly 1.9 to 1.8), crystalline resin / second carbon-based conductive filler = 80/20 to 55 / 45, preferably 75/25 to 55/45, more preferably about 70/30 to 60/40. In the case of a filler (for example, acetylene black) having a specific gravity of 0.3 to 1.6 (particularly 0.4 to 1.5), crystalline resin / second carbon-based conductive filler = 90/10 to 70. / 30, preferably 90/10 to 80/20, more preferably about 90/10 to 85/15.

(C) Other additives The second conductive layer is made of a conventional additive such as other polymer (amorphous resin, amorphous elastomer, crystalline elastomer, rubber, etc.), plasticizer, other Conductive filler, conductive polymer, stabilizer (thermal stabilizer, ultraviolet absorber, light stabilizer, antioxidant, etc.), dispersant, antistatic agent, colorant, lubricant, crystal nucleating agent, flame retardant, It may contain flame retardant aids, fillers, impact resistance improvers, reinforcing agents, foaming agents, antibacterial agents and the like. These additives can be used alone or in combination of two or more. The ratio of these additives is, for example, 10 parts by weight or less, preferably 0.01 to 5 parts by weight, more preferably 0.05, with respect to 100 parts by weight of the total of the crystalline resin and the second conductive filler. About 3 parts by weight (particularly 0.1 to 2 parts by weight).

  The second conductive layer may contain a soft component such as an elastomer or rubber as long as the ratio is as described above, but substantially includes a soft component such as an elastomer or rubber (especially an elastomer such as an amorphous elastomer). It does not need to contain. In the present invention, the second conductive layer having a thin wall and high conductivity can be prepared without containing a soft component, although the resin component is substantially formed of a crystalline resin.

(Characteristics of the second conductive layer)
Although the shape of a 2nd conductive layer is not specifically limited, Usually, it is a sheet form or a film form. The second conductive layer may be a thin layer having an average thickness of 200 μm or less. Specifically, the average thickness of the second conductive layer can be selected from a range of about 5 to 150 μm (for example, 5 to 120 μm), preferably 10 to 110 μm, more preferably about 15 to 100 μm (particularly 20 to 100 μm). In applications where thin walls are required, the thickness may be, for example, about 25 to 50 μm (particularly 30 to 45 μm).

  The second conductive layer also has high thickness uniformity, and the thickness variation ratio (maximum thickness / minimum thickness) is, for example, 1.5 or less (for example, 1 to 1.5), preferably 1.01 to 1. 4, more preferably about 1.03 to 1.3 (particularly 1.05 to 1.25), for example, about 1.1 to 1.2. Since the second conductive layer has a uniform thickness, for example, even when a plurality of films are stacked, a large gap does not occur, and the adhesiveness is high, and the uniformity and stability of the conductivity are also high. The thickness variation ratio can be measured by the method described in Examples described later.

  The second conductive layer has high conductivity while being thin. That is, the volume resistivity of the second conductive layer is 0.1 to 1500 Ω · cm, preferably 1 to 1000 Ω · cm, more preferably 2 to 500 Ω · cm (particularly 3 to 100 Ω · cm). For example, about 1-50 ohm * cm (especially 2-10 ohm * cm) may be sufficient. The volume resistance value of the second conductive layer is, for example, about 0.001 to 5Ω, preferably about 0.01 to 3Ω, and more preferably about 0.1 to 1Ω.

  The second conductive layer is also excellent in solvent resistance and has a weight change rate (weight increase rate) of 10% by weight or less after being immersed in tetrahydrofuran at 25 ° C. for 24 hours. % By weight, preferably 0.5 to 5.0% by weight, more preferably about 0.5 to 4.0% by weight. For applications that require high solvent resistance, for example, 0.5 to 3%. It may be about 0.0% by weight, preferably 0.5 to 2.0% by weight, more preferably about 0.5 to 1.5% by weight (particularly 0.5 to 1.0% by weight).

  The specific gravity of the second conductive layer is, for example, about 0.75 to 1.20, preferably about 0.80 to 1.18, more preferably about 0.85 to 1.15 (particularly 0.90 to 1.15). It is. When the crystalline resin is a polypropylene resin, the specific gravity of the second conductive layer is, for example, 0.95 to 1.2, preferably 0.96 to 1.18, and more preferably 0.97 to 1.15. It may be about (especially 1.0 to 1.1).

  In the second conductive layer, another layer may be further laminated on the surface opposite to the side to be bonded to the first conductive layer. The other layer may be a layer exemplified as another layer in the first conductive layer, and as described above, the other layer may be the same conductive layer as the first conductive layer. Good.

(Characteristics of the first and second conductive layers)
The first conductive layer and the second conductive layer are both excellent in solvent resistance and high in conductivity even though they are thin. Each of the first conductive layer and the second conductive layer may have a volume resistivity of 10 ⁵ Ω · cm or less (for example, about 0.01 to 10 ⁵ Ω · cm), for example, 10 ⁴ Ω. · Cm or less (for example, about 0.1 to 10 ⁴ Ω · cm), preferably 10 ³ Ω · cm or less (for example, about 1 to 10 ³ Ω · cm), more preferably 10 ² Ω · cm or less (particularly 10 Ω · cm or less).

In particular, a conductive laminated film obtained by laminating a first conductive layer and a second conductive layer without using an adhesive layer can improve conductivity and solvent resistance while maintaining mechanical properties such as flexibility. . The volume resistivity of the conductive laminated film may be 10 ⁵ Ω · cm or less, for example, 1 to 10000 Ω · cm (for example, 2 to 1000 Ω · cm), preferably 3 to 500 Ω · cm, more preferably About 5-100 ohm * cm (especially 10-50 ohm * cm) may be sufficient.

  The first conductive layer and the second conductive layer have high solvent resistance and particularly low permeability to polar solvents. Specifically, in the conductive laminated film, in accordance with the method described in the examples described later, propylene carbonate is interposed between the two conductive laminated films laminated with the second conductive layers facing each other. The weight change rate (weight increase rate) after 14 days is, for example, 5% by weight or less, preferably 1% by weight or less (for example, 0.01 to 1% by weight), more preferably 0.5%. It may be not more than wt% (for example, 0.1 to 0.5 wt%).

  The average thickness of the conductive laminated film can be selected from a range of about 1 to 300 μm, for example, from a range of about 1 to 250 μm (for example, 5 to 200 μm), preferably 10 to 150 μm, more preferably. Is about 15 to 120 μm (particularly 20 to 100 μm), and usually about 25 to 90 μm (for example, 30 to 80 μm).

  In the conductive laminated film, the average thickness ratio between the first conductive layer and the second conductive layer can be selected from a range of about 1st conductive layer / second conductive layer = 10/1 to 1/100. 5/1 to 1/50, preferably 3/1 to 1/30, more preferably 1/1 to 1/20 (particularly 1/2 to 1/15), and 1/2 to 1/10. It may be about (for example, 1/3 to 1/9).

  The conductive laminated film is excellent in flexibility and can be made into a sheet and manufactured in a roll-to-roll manner, so that the productivity is high and the industrial value is high.

(Method for producing first conductive layer)
The first conductive layer formed of a cured product of the photocurable composition is a coating step of applying a liquid photocurable composition on a substrate, and the applied photocurable composition is irradiated with light. It is manufactured through a curing process that cures.

  As a coating method of the photocurable composition, conventional methods such as a roll coater, an air knife coater, a blade coater, a rod coater, a reverse coater, a bar coater, a comma coater, a dip squeeze coater, a die coater, a gravure coater, a micro coater, and the like. Examples include a gravure coater, a silk screen coater method, a dip method, a spray method, and a spinner method. Of these methods, the bar coater method and the gravure coater method are widely used. If necessary, the coating solution may be applied a plurality of times.

  When the photocurable composition contains an organic solvent, it may be dried as necessary after coating. The drying may be performed at a temperature of, for example, 30 to 150 ° C, preferably 40 to 100 ° C, more preferably about 50 to 70 ° C.

  As a method of irradiating the photocurable composition with light, a method of irradiating light energy rays such as radiation (gamma rays, X-rays, etc.), ultraviolet rays, visible rays, electron beams (EB) can be used. Of these methods, the method of irradiating with ultraviolet rays and electron beams is preferable.

In the method of irradiating ultraviolet rays, as the light source, for example, in the case of ultraviolet rays, a Deep UV lamp, a low-pressure mercury lamp, a high-pressure mercury lamp, an ultrahigh-pressure mercury lamp, a halogen lamp, a laser light source (helium-cadmium laser, excimer laser, etc.) Light source) or the like. The amount of irradiation light (irradiation energy) varies depending on the thickness of the coating film, but may be, for example, about 50 to 10,000 mJ / cm ² , preferably 70 to 7000 mJ / cm ² , and more preferably about 100 to 5000 mJ / cm ² .

  As a method of irradiating an electron beam, a method of irradiating an electron beam with an exposure source such as an electron beam irradiation apparatus can be used. The irradiation amount (dose) varies depending on the thickness of the coating film, but is, for example, about 1 to 200 kGy (gray), preferably about 10 to 180 kGy, and more preferably about 30 to 150 kGy (particularly about 50 to 120 kGy). The acceleration voltage is, for example, about 10 to 1000 kV, preferably about 50 to 500 kV, and more preferably about 100 to 300 kV.

  In addition, you may perform irradiation of an electron beam in inert gas (for example, nitrogen gas, argon gas, helium gas etc.) atmosphere as needed.

  In the present invention, the method of irradiating with an electron beam is particularly preferred because polymerization can be performed without using a polymerization initiator and a cured product having high weather resistance can be produced.

(Method for producing second conductive layer)
In the case of the conductive laminated film in which the first conductive layer and the second conductive layer are laminated, the second conductive layer may be manufactured in advance instead of the base material.

  After extruding the crystalline resin composition, the second conductive layer may be stretched or rolled while heating the obtained sheet.

  The crystalline resin composition may be a pellet prepared by previously melt-kneading the crystalline resin and the second conductive filler. As a method of melt kneading, a conventional method, for example, a method using a mixer such as a pressure kneader kneader, a Banbury mixer, a mixing roll, or the like can be used. Furthermore, you may pelletize using a feeder luder etc. after melt-kneading. In this invention, workability | operativity, such as adjustment between each process of sheet | seat processing, can be improved by pelletizing. In addition, as a method of melt kneading, each component may be dry-mixed with a Henschel mixer or a ribbon mixer, and melt kneading and pelletization may be simultaneously performed using a single screw or twin screw extruder.

  The obtained pellet or dry mixture is produced into a sheet using an extruder (for example, a single-screw or twin-screw extruder) or a calendar molding machine, and usually the pellet is melt-kneaded in the extruder, Molding is performed by extruding from the slit of the die (die) at the tip of the extruder. The die (die) may be a ring die used for inflation molding, but usually a T die such as a multi-manifold die or a flat die can be used. Further, the extruded sheet is cooled by a cooling roll and can be wound on a sheet winder.

  The conditions for extrusion molding can be selected according to the type of the extruder and the crystalline resin, and the molding temperature is usually about 100 to 280 ° C, preferably about 150 to 260 ° C, more preferably about 180 to 250 ° C. The cooling temperature by a cooling roll is 80-200 degreeC, for example, Preferably it is 100-180 degreeC, More preferably, it is about 120-160 degreeC. Further, the gap (clearance or gap) of the extrusion slit is 0.5 to 2.0 mm, preferably 0.6 to 1.5 mm, and more preferably 0.7 to 1.0 mm. The take-up speed (winding speed) is, for example, about 0.1 to 70 m / min, preferably 0.5 to 40 m / min, more preferably about 1.5 to 30 m / min (particularly 2 to 10 m / min). .

  In the present invention, each resin composition is extruded to 120 to 500 μm, preferably 130 to 400 μm, and more preferably 130 to 300 μm (particularly 130 to 250 μm). The winding speed is adjusted.

  In the present invention, the sheet is once adjusted to such a thickness by extrusion molding. In this state, the second conductive filler (particularly conductive carbon black) is appropriately aggregated (aggregated) in the sheet. High conductivity is probably due to the formation of a network structure. The obtained sheet has a volume resistivity of 1000 Ω · cm or less, preferably 0.1 to 500 Ω · cm, more preferably 0.2 to 200 Ω · cm (particularly 0.3 to 100 Ω · cm). .

  The roll sheet obtained by extrusion molding is rewound and stretched or rolled. The stretching or rolling process is performed in a state where the sheet is heated. In the method of the present invention, the stretching or rolling process is performed in order to prevent the network structure of the conductive filler formed by the extrusion from being destroyed by the stretching or rolling process. The heating temperature in is controlled. The heating temperature in the stretching or rolling treatment is a temperature range of (mp-40) ° C. to (mp-5) ° C., preferably (mp−35) ° C. to (mp, where mp is the melting point of the crystalline resin. −5) ° C., more preferably (mp-30) ° C. to (mp-10) ° C. [particularly, (mp-30) ° C. to (mp-15) ° C.]. If the heating temperature is too high, the conductivity decreases because the molecular chain of the molten polymer enters the network structure of the conductive filler. In addition, the polymer is softened or melted, and tends to be in close contact with the rotating roll or difficult to tear and wind. On the other hand, if the heating temperature is too low, a high shearing force is applied to the resin composition and the network structure is destroyed. Moreover, since the fluidity | liquidity of a polymer is low, a sheet | seat is not fully thinned but it becomes easy to tear. On the other hand, in the method of the present invention, the heating temperature in stretching or rolling is controlled to an appropriate range. For example, the network structure is reduced in the thickness direction so that the pantograph is folded. Alternatively, high conductivity can be maintained even after the rolling process.

  In the stretching or rolling treatment, the thickness of the thin sheet after the treatment may be adjusted to about 1 / 1.2 to 1/10 times that of the sheet before the treatment, for example, 1 / 1.5-1 to 1. / 8 times, preferably 1/2 to 1/5 times, more preferably about 1 / 2.5 to 1 / 4.5 times.

  The stretching treatment may be uniaxial stretching or biaxial stretching. The biaxial stretching may be simultaneous biaxial stretching or sequential biaxial stretching. The draw ratio may be adjusted so that the thickness of the thin sheet falls within the above range, and can be selected from a range of about 1.1 to 10 times, preferably 1.5 to 5 times, more preferably 2 to 5 times. It is about twice.

  The load of the rolling treatment can be selected from about 100 kN or less, for example, about 0.1 to 100 kN, preferably 0.5 to 50 kN, more preferably about 1 to 30 kN (particularly 2 to 10 kN). If the rolling pressure increases, the shearing force applied to the thick sheet increases, or the volume-specific low efficiency of the thin sheet tends to increase. Therefore, the load applied to the sheet from the heating roll is preferably small.

  In the rolling process, a drawing process may be applied in the longitudinal direction of the sheet by increasing the winding speed of the winder from the supply speed of the original sheet. The ratio of the winding speed to the supply speed (winding speed / supply speed) is, for example, about 1 to 10 times, preferably 1.5 to 8 times, more preferably 2 to 5 times (particularly 3 to 4.5 times). is there. This ratio can be selected from this range in accordance with the processing temperature and load load, and the thickness of the sheet may be adjusted by adjusting these conditions. In the rolling process, the relationship between the load load and the speed ratio is preferably such that the load ratio is reduced and the speed ratio is increased from the viewpoint that the sheet thickness can be made uniform and the conductivity can be improved. Furthermore, from the point which makes sheet | seat thickness uniform and improves electroconductivity, the extending | stretching process which does not load a load may be sufficient. In particular, a conductive filler having a cavity structure such as ketjen black can maintain high conductivity even after stretching or rolling because the destruction of the cavity structure can be suppressed.

  Further, in the stretching or rolling treatment, a lubricant or a release agent may be applied to the sheet surface in order to improve workability, or a plurality of rolls may be combined.

  The obtained second conductive layer may be annealed by a conventional method in order to release residual strain in the thinned layer. The annealing temperature is, for example, (mp-60) ° C to (mp-5) ° C, preferably (mp-55) ° C to (mp-10), where mp is the melting point of the crystalline resin. More preferably, it is (mp-50) ° C to (mp-20) ° C.

(Adhesive layer)
The adhesive layer (seal layer or adhesive) is formed of an acid-modified olefin resin, and in order to seal the first conductive layer and the second conductive layer and enclose a solvent or the like, The conductive layer and the second conductive layer are bonded.

  Examples of the olefin resin constituting the acid-modified olefin resin include homo- or copolymers of α-olefins such as ethylene, propylene, butene, and methylpentene-1. Examples of such olefin resins include polyethylene resins (polyethylene, ethylene-propylene copolymer, ethylene-butene copolymer, etc.), polypropylene resins (polypropylene, propylene-ethylene random copolymer, propylene-ethylene). Examples thereof include block copolymers and propylene-butene copolymers. Among these, polyethylene resins such as high-density polyethylene and polypropylene resins are preferable, and polypropylene resins are particularly preferable from the viewpoint of excellent lightness and heat resistance. As a polypropylene resin, the polypropylene resin illustrated as a crystalline resin of a 2nd conductive layer can be illustrated.

  The acid-modified olefin resin may be an olefin resin modified with a carboxylic acid, and specifically, an olefin resin having a carboxyl group and / or an acid anhydride group. The modification method using an acid is not particularly limited as long as a carboxyl group and / or an acid anhydride group is introduced into the skeleton of the olefin resin. From the viewpoint of solvent resistance and mechanical properties, the carboxyl group and / or Or the method of introduce | transducing the monomer which has an acid anhydride group by copolymerization is preferable. The form of copolymerization may be random copolymerization or block copolymerization, but graft copolymerization is preferred from the viewpoint of improving adhesion to the conductive layer.

  Examples of the monomer having a carboxyl group and / or an acid anhydride group include an unsaturated monocarboxylic acid [for example, (meth) acrylic acid, crotonic acid], an unsaturated dicarboxylic acid or an acid anhydride thereof [for example, ( Anhydride) maleic acid, fumaric acid, (anhydrous) citraconic acid, (anhydrous) itaconic acid, etc.]. These monomers can be used alone or in combination of two or more. Of these monomers, unsaturated dicarboxylic acids such as (anhydrous) maleic acid or acid anhydrides thereof are preferable, and maleic anhydride is particularly preferable from the viewpoint of improving adhesiveness.

  The proportion of the monomer is 0.01 to 10 parts by weight, preferably 0.05 to 5 parts by weight, and more preferably 0.1 to 3 parts by weight (particularly 0.1. 2 to 1 part by weight). If the proportion of the monomer is too small, the adhesion to the conductive layer is lowered, and conversely if it is too much, the solvent resistance is lowered.

  The melting point of the acid-modified olefin resin (particularly acid-modified polypropylene resin) can be selected from the range of about 80 to 170 ° C., for example, in the method based on ASTM D2117. It is about 160 ° C, preferably 120 to 150 ° C, more preferably about 120 to 140 ° C (particularly 120 to 135 ° C). If the melting point of the acid-modified olefin resin is too low, the heat resistance and mechanical properties are reduced, and conversely if it is too high, the adhesion to the conductive layer is reduced.

  Furthermore, the acid-modified olefin resin preferably has a melting point lower than the melting point of the crystalline resin contained in the second conductive layer. For example, the melting point of the crystalline resin is, for example, 5 to 80 ° C., The melting point may be preferably about 10 to 60 ° C, more preferably about 20 to 50 ° C. If the melting point of the acid-modified olefin resin is higher than that of the crystalline resin, it is difficult to seal (heat seal) the conductive layer, and it is difficult to firmly bond the two by a simple method.

  The melt flow rate (MFR) of acid-modified olefin resin (particularly acid-modified polypropylene resin) is a method based on ASTM D1238 and is about 0.3 to 20 g / 10 minutes, for example, 0.5 to 15 g. / 10 minutes, preferably 0.8 to 10 g / 10 minutes, more preferably about 1 to 5 g / 10 minutes (particularly 1.2 to 3 g / 10 minutes). If the MFR is too large, the mechanical properties are lowered, and if it is too small, the adhesiveness tends to be lowered.

  The yield point stress of the acid-modified olefin resin (particularly acid-modified polypropylene resin) is, for example, 5 to 50 MPa, preferably 10 to 30 MPa, more preferably 12 to 25 MPa (particularly 15 to 15 MPa) in accordance with ASTM D638. 20 MPa). The strength at break is a method based on ASTM D638, and is, for example, about 3 to 50 MPa, preferably about 5 to 30 MPa, and more preferably about 8 to 25 MPa (particularly 10 to 20 MPa).

  The Izod impact strength of the acid-modified olefin resin (particularly acid-modified polypropylene resin) may be about 10 J / m or more by a method based on ASTM D256, for example, 10 to 1000 J / m, preferably 30. It is about -500 J / m, More preferably, it is about 50-300 J / m (especially 100-150 J / m). If the Izod impact strength is too low, the mechanical properties are lowered. Conversely, if it is too high, the solvent resistance tends to be lowered.

  Acid-modified olefin resins (particularly acid-modified polypropylene resins) are also excellent in solvent resistance (swelling resistance to organic solvents). For example, the weight change rate after being immersed in diethyl carbonate at 23 ° C. for 24 hours. May be 10 wt% or less, for example, 5 wt% or less (for example, 0.1 to 5 wt%), preferably 0.2 to 3 wt%, more preferably 0.3 to 2 wt% ( In particular, it is about 0.5 to 1.5% by weight). In addition, in this specification, the test method of the swelling resistance with respect to diethyl carbonate can be measured by the method as described in the Example mentioned later.

  The adhesive layer may contain conventional additives exemplified in the section of the second conductive layer.

  The adhesive layer only needs to be able to bond the first conductive layer and the second conductive layer in order to seal the conductive layer (especially, a conductive film such as a current collector of a lithium ion battery), and its shape is particularly limited. Usually, it is in the form of a sheet or film. The adhesive layer may be used for sealing in a state where a solvent is sealed in a conductive film such as a current collector, for example. The adhesive layer may be a laminate (for example, a laminate of 2 to 3 layers), for example, an adhesive layer formed of a laminate in which layers formed of different acid-modified olefin resins are laminated. May be. Further, the adhesive layer may be laminated with another adhesive layer (for example, a layer formed of a hot-melt adhesive resin such as a polypropylene resin) or an adhesive layer.

  The average thickness of the adhesive layer may be 10 μm or more, for example, about 10 to 200 μm, preferably about 20 to 150 μm, and more preferably about 25 to 120 μm (particularly about 30 to 100 μm). If the thickness of the adhesive layer is too thin, the sealing force is reduced when encapsulating a solvent or the like.

  The adhesive layer may be surface-treated in order to improve adhesion, and is a conventional surface treatment such as corona discharge treatment, flame treatment, plasma treatment, ozone or ultraviolet irradiation treatment, cleaning treatment using an organic solvent, The surface treatment may be performed by chemical treatment using acid or alkali, or polishing treatment using abrasive paper or sandblast.

(Characteristics of composite encapsulant)
The composite encapsulant has high adhesive strength between the first conductive layer and the second conductive layer, and the peel strength between the two may be 0.2 N / mm or more, for example, 0.2 to 1 N / mm , Preferably 0.3 to 0.9 N / mm, more preferably about 0.4 to 0.8 N / mm (particularly 0.5 to 0.7 N / mm). The composite encapsulant of the present invention has such a high adhesive strength despite its high solvent resistance. In addition, in this specification, the peelability test method can be measured by the method described in Examples described later.

  The composite encapsulant is a sheet or a film, but the adhesive layer is usually laminated in a partial region of the first and second conductive layers, for example, the first and second conductive layers. You may laminate | stack in the area | region of an edge part or a peripheral part.

  In the composite encapsulant, the average thickness ratio between the total thickness of the first conductive layer and the second conductive layer and the adhesive layer is the total thickness of the first and second conductive layers / adhesive layer = 40/200 to 100/20, preferably 40/150 to 100/25, more preferably 40/120 to 100/30 (particularly 40/100 to 100/30) degrees.

[Method for producing composite encapsulant]
The method for producing the composite encapsulant of the present invention is not particularly limited as long as the adhesive layer can be heat-sealed to bond the first conductive layer and the second conductive layer. A production method including a step of thermocompression bonding is preferable.

  The adhesive layer subjected to the thermocompression bonding step is usually in the form of a sheet or film. As the adhesive layer, an adhesive layer separately prepared in the form of a sheet may be laminated on the conductive layer, or a liquid composition for forming the adhesive layer may be applied to the surface of the conductive layer. The adhesive layer can be formed into a sheet shape by a conventional method, for example, a thermoforming method for forming into a sheet shape by melt extrusion, rolling, hot pressing or the like, a casting method for processing into a sheet shape by casting on a substrate, etc. The method can be used. The liquid adhesive layer may be, for example, a dispersion in which an acid-modified olefin resin is dispersed in an organic solvent (for example, toluene, xylene, decalin, methylcyclohexane, methyl ethyl ketone, ethyl acetate, etc.). In the dispersion of the organic solvent, it may be dried after being applied to the surface of the conductive layer.

  The heating temperature in thermocompression bonding is not limited as long as the acid-modified olefin resin can be melted, and is higher than the melting point of the acid-modified olefin resin (for example, about 5 to 50 ° C. higher than the melting point of the acid-modified olefin resin, preferably 10 to 45). It may be a temperature as high as about ° C, more preferably as high as about 15 to 40 ° C. The heating temperature in the thermocompression bonding is a temperature lower than the melting point of the crystalline resin of the second conductive layer (for example, a temperature 1 to 50 ° C. lower than the melting point of the crystalline resin, preferably about 3 to 40 ° C., The temperature may preferably be about 5 to 30 ° C.).

  The pressurizing pressure in thermocompression bonding is, for example, about 0.1 to 50 MPa, preferably about 0.2 to 40 MPa, and more preferably about 0.3 to 30 MPa (particularly 0.5 to 20 MPa).

  Hereinafter, the present invention will be described in more detail based on examples, but the present invention is not limited to these examples. Evaluation of the characteristics of the compounding components used in Examples and Comparative Examples, the conductive laminated films obtained in Examples and Comparative Examples, and composite encapsulating sheets was measured by the following method.

[Specific gravity of conductive layer]
Based on JIS K7112, specific gravity was calculated | required from the sample density measured using the electronic hydrometer ("Electronic Densometer SD-200L" by Alpha Mirage Co., Ltd.). In addition, in a bulky sample or the like, when a sample shape appropriate for measurement could not be obtained, the sample was cut out after being previously formed by hot pressing.

[Melting point / glass transition temperature of second conductive layer]
A melting point (mp) and a glass transition temperature (Tg) of a resin composition (for example, pellets) prepared by melt kneading were measured. The measurement was performed by a normal thermal analysis method using a differential scanning calorimeter (DSC) (trade name “Q2000”, manufactured by TA Instruments Japan Co., Ltd.).

[Average thickness and uniformity of second conductive layer]
Using a micrometer ("Digimatic Micrometer MDC25MJ" manufactured by Mitutoyo Co., Ltd.), measurement is performed at 10 or more points at 25 mm intervals in the sheet width direction (TD), and the sheet flow direction (MD) The measurement was performed at 10 points or more at intervals of 25 mm, and the arithmetic average value was obtained from the measured values of 20 points or more in total. Similarly, the uniformity (or stability) of the thickness is determined by measuring the thickness in the flow direction (MD) of 1 m in the center of the sheet at intervals of 50 mm, and obtaining the average value and the minimum of the obtained measurement values at the maximum of 5 points. The average value of 5 points was calculated as thickness variation ratio = (maximum average value / minimum average value). The smaller the ratio, the more stable the sheet thickness.

[Conductivity (volume resistivity)]
A seal with a Φ3 mm hole was attached to both sides of the sample, silver paste was applied, the resistance value (Ω) was measured with a tester, and the volume resistivity (Ω · cm) was calculated according to the following formula.

Volume resistivity (Ω · cm) = resistance (Ω) × area (cm ² ) / thickness (cm)

[Solvent resistance of second conductive layer]
The film was cut into 100 mm × 100 mm, and the initial weight: A (mg) was measured. Next, the film was completely immersed in tetrahydrofuran (THF) at 25 ° C. and allowed to stand for 24 hours, and then the surface of the film taken out was wiped and dried, and the weight: B (mg) was measured again. Based on the following formula, the weight change rate (weight increase rate) was calculated.

    Weight change rate (%) = [(BA) / A] × 100 (%)

[Storage elastic modulus E ′ of first conductive layer]
About the obtained test piece, using a dynamic viscoelasticity measuring apparatus (manufactured by TA Instruments Japan Co., Ltd., RSA-III) under the conditions of a heating rate of 5 ° C./min and a frequency of 10 Hz, The storage elastic modulus (E ′) at 50 ° C. to 250 ° C. was determined.

[Flexibility of conductive laminated film]
The specimen was cut into 2 cm × 15 cm strips, subjected to a flexibility test in accordance with JIS K5600, whether or not a mandrel having a diameter of 10 mm was cracked, and evaluated according to the following criteria.

○: No cracking or cracking occurred ×: Cracking or cracking occurred.

[Solvent permeability of conductive laminated film]
Two pieces of the conductive laminated film having a size of 10 cm × 10 cm were cut out and welded in a width of 1 cm in each of the three directions with the first conductive layer on the outside. From the unwelded portion, 2 g of propylene carbonate was added, and a width of 1 cm was welded and sealed. Furthermore, the welded part was sealed with aluminum tape to obtain a test specimen. The test specimen was placed in a desiccator and allowed to stand at 23 ° C. and 50 Rh%, and the change in weight over time was calculated and evaluated based on the following formula. In this test, if the weight change (%) after 14 days is 0.5% or less, the solvent permeability is excellent.

    Weight change rate (%) = {[(weight of specimen immediately after enclosing solvent) − (weight of specimen after 14 days)] / (weight of encapsulated solvent)} × 100

[Peel strength of composite encapsulant]
Each end of the peel strength between the first conductive layer and the second conductive layer of the composite encapsulant according to JIS K6854-2, using a tensile tester (Orientec Co., Ltd., RTM-1210). Then, the two layers were pulled at a pulling speed of 5 mm / min, peeled 180 °, and measured.

[Solvent resistance of adhesive layer]
10 ml of diethyl carbonate was put in a petri dish, the adhesive layer was immersed in diethyl carbonate, allowed to stand at 23 ° C. for 24 hours, and the weight change rate before and after the solvent immersion was determined by the following formula. In this test, if the weight change (%) is 5% or less, it indicates that the solvent resistance is excellent.

    Weight change rate (%) = {[(weight of coating film after immersion in solvent) − (weight of coating film before immersion in solvent)] / (weight of coating film before immersion in solvent)} × 100

[Composition ingredients]
(First conductive layer)
Trifunctional acrylate: Pentaerythritol triacrylate, “PETIA” manufactured by Daicel Cytec Co., Ltd.
Ring-containing bifunctional acrylate: Tricyclodecane diacrylate, “IRR214K” manufactured by Daicel-Cytec Co., Ltd.
Bifunctional urethane acrylate: highly weather-resistant urethane acrylate, “EBECRYL8402” manufactured by Daicel-Cytec Co., Ltd.
Photopolymerization initiator: hydroxycyclohexyl phenyl ketone, “Irgacure 184” manufactured by BASF Japan Ltd.
Furnace carbon black: conductive carbon black, average primary particle size 50 nm, BET specific surface area 33 m ² / g, “# 4300” manufactured by Tokai Carbon Co., Ltd.

(Second conductive layer)
Polypropylene: Prime polymer “E-100GPL”, specific gravity 0.90
Polyamide 12: “L1901” manufactured by Daicel Evonik Co., Ltd., specific gravity 1.01
Carbon black: “Denka Black HS-100, manufactured by Denki Kagaku Kogyo Co., Ltd., average particle size 48 nm, BET specific surface area 39 m ² / g, specific gravity 1.9

(Adhesive layer)
Acid-modified PP pellet 1: polypropylene grafted with maleic acid graft, “Admer HE040” manufactured by Mitsui Chemicals, melting point 125 ° C., MFR 1.6 g / 10 min, yield point stress 18.6 MPa, breaking point strength 11 MPa, Izod impact strength 110 J / M
Acid-modified PP pellet 2: polypropylene grafted with maleic acid graft, “Admer QE060” manufactured by Mitsui Chemicals, melting point 140 ° C., MFR 7.0 g / 10 min, yield point stress 21.6 MPa, breaking point strength 35 MPa, Izod impact strength 70 J / M
Acid-modified PP pellet 3: polypropylene grafted with maleic acid graft, “Admer QF551” manufactured by Mitsui Chemicals, melting point 135 ° C., MFR 5.7 g / 10 min, yield point stress 15.7 MPa, breaking point strength 19 MPa, Izod impact strength 500 J / M
Liquid acid-modified PP: acid-modified polypropylene, “Unistor H-100” manufactured by Mitsui Chemicals, Inc., viscosity 160 mPa · s, solid content 20%
Urethane laminating agent 1: polyurethane / isocyanate adhesive, “M329” manufactured by Toyo Morton Co., Ltd., curing agent: polyisocyanate “CAT-8B”
Urethane-based laminating agent 2: polyether / isocyanate-based adhesive, “969” manufactured by Toyo Morton Co., Ltd., curing agent: polyisocyanate “A-5”
Epoxy resin: “AW136N” manufactured by Nagase ChemteX Corporation, curing agent “HY994”

[Example of production of second conductive layer]
68 parts by weight of homopolypropylene as a resin component and 32 parts by weight of carbon black as a conductive filler were blended in a pressure kneader kneader, melt mixed, and further pelletized with a feeder ruder. When the characteristics of the pellet were measured, the specific gravity was 1.08, the melting point (mp) was 166 ° C., and the glass transition temperature (Tg) was −22 ° C.

  The obtained pellets are supplied to a T-die extrusion molding machine, extruded into a sheet shape from an extrusion slit gap of 0.8 mm at an extrusion temperature of 230 ° C., wound at a winding speed of 2.5 m / min, and have a thickness of 140 μm. Sex sheet was obtained. The volume resistivity of this sheet was 8 Ω · cm.

  Next, while unwinding the roll sheet, the roll load is 5 kN between the two heating rolls having a surface temperature of the heating roll of 140 ° C. (thermal stretching temperature difference = composition melting point−heating roll surface temperature = −25 ° C.). Then, while being heated from both sides of the sheet, the film was passed at a feeding speed of 1 m / min and a winding speed of 2.8 m / min to perform a heat stretching process. The obtained second conductive layer has a thickness of 40 μm, a volume resistivity of 8 Ω · cm, a thickness variation ratio of 1.1, a weight change rate of THF of 0.8%, and is smooth and has a thickness variation. There was almost no solvent resistance.

[Example of production of conductive laminated film]
The acrylate was weighed in a 150 ml container with a lid at a ratio shown in Table 1, and dissolved in a mixed solvent of methyl ethyl ketone (MEK) and toluene (TOL) [MEK / TOL = 50/50 (weight ratio)]. Carbon black was added to this solution, and a dispersion composition was prepared using a self-revolving mixing deaerator (“ARE-250” manufactured by Shinkey Co., Ltd.).

  The obtained dispersion composition was coated on a release paper with a bar coater to a thickness of about 50 μm and dried at 60 ° C. The dried composition was irradiated with an electron beam having an acceleration voltage of 150 kV and a dose of 100 kGy in a nitrogen atmosphere to prepare a cured coating film (second conductive layer). The storage elastic modulus was evaluated about the 1st conductive layer obtained by peeling a release paper.

  Furthermore, the dispersion composition was applied to a thickness of about 10 μm on the second conductive layer obtained in the production example, and dried at 60 ° C. The dried composition was irradiated with an electron beam having an acceleration voltage of 150 kV and a dose of 100 kGy in a nitrogen atmosphere to prepare a cured coating film (first conductive layer). About the obtained electroconductive laminated sheet, flexibility, solvent permeability, and electroconductivity were evaluated.

  These results are shown in Table 1.

  The obtained conductive laminated film is flexible, has low solvent permeability, and high conductivity.

Example 1
The acid-modified PP pellet 1 was hot-pressed using a press molding machine (manufactured by Toyo Seiki Seisakusho Co., Ltd.) at a temperature of 150 ° C. and a pressure of 20 MPa to produce a 60 μm thick adhesive layer. The produced adhesive layer was evaluated for solvent resistance. The adhesive layer is laminated on the first conductive layer in the conductive laminated film obtained in the production example, and the same conductive laminated film is further placed on the adhesive layer on the second conductive layer side. Laminate toward the adhesive layer and use a press molding machine (manufactured by Toyo Seiki Seisakusho Co., Ltd.) to perform thermocompression bonding under conditions of a temperature of 145 ° C., a pressure of 10 MPa, and 300 seconds to produce a composite encapsulating sheet and peeling It used for the test. The average thickness of the adhesive layer after pressure bonding was 50 μm, and the average thickness of the conductive laminated film was 40 μm.

Example 2
An adhesive layer having a thickness of 60 μm was prepared in the same manner as in Example 1 except that the acid-modified PP pellet 2 was used instead of the acid-modified PP pellet 1. The produced adhesive layer was evaluated for solvent resistance. The adhesive layer is laminated on the first conductive layer in the conductive laminated film obtained in the production example, and the same conductive laminated film is further placed on the adhesive layer on the second conductive layer side. Laminated toward the adhesive layer, a composite sealing sheet was prepared in the same manner as in Example 1, and subjected to a peel test. The average thickness of the adhesive layer after pressure bonding was 50 μm, and the average thickness of the conductive laminated film was 40 μm.

Example 3
An adhesive layer having a thickness of 60 μm was prepared in the same manner as in Example 1 except that the acid-modified PP pellet 3 was used instead of the acid-modified PP pellet 1. The produced adhesive layer was evaluated for solvent resistance. The adhesive layer is laminated on the first conductive layer in the conductive laminated film obtained in the production example, and the same conductive laminated film is further placed on the adhesive layer on the second conductive layer side. Laminated toward the adhesive layer, a composite sealing sheet was prepared in the same manner as in Example 1, and subjected to a peel test. The average thickness of the adhesive layer after pressure bonding was 45 μm, and the average thickness of the conductive laminated film was 40 μm.

Example 4
On the 1st conductive layer in the electroconductive laminated sheet obtained by the said manufacture example, after apply | coating liquid acid modification PP using an applicator, it dried at 80 degreeC and formed the contact bonding layer. On the adhesive layer obtained, the same conductive laminated film was further laminated on the adhesive layer with the second conductive layer side facing the adhesive layer, and a press molding machine (manufactured by Toyo Seiki Seisakusho Co., Ltd.). ) Was thermocompression bonded under the conditions of a temperature of 150 ° C. and a pressure of 10 MPa for 60 seconds to prepare a composite sealing sheet, which was subjected to a peel test. The release layer was coated with an applicator to a thickness of 250 μm, and the solvent resistance of the adhesive layer prepared by drying treatment as described above was evaluated. The average thickness of the adhesive layer after pressure bonding was 20 μm, and the average thickness of the conductive laminated film was 50 μm.

Comparative Example 1
18 parts by weight of the urethane laminating agent 1 and 18 parts by weight of the curing agent were dissolved in 38.6 parts by weight of ethyl acetate to prepare a laminating agent solution 1.

  On the first conductive layer in the conductive laminated film obtained in the above production example, the urethane-based laminating agent solution 1 was applied using a bar coater, and then dried at 80 ° C. to form an adhesive layer having a thickness of 5 μm. Formed. The same conductive laminated film was further laminated on the obtained adhesive layer with the second conductive layer side facing the adhesive layer, and pressure-bonded using a table laminator under conditions of pressure 0.2 MPa and 3 m / min. Then, it hardened | cured by processing at 40 degreeC for 15 hours, and then at 80 degreeC for 4 hours, and produced the composite sealing sheet. The obtained composite encapsulating sheet was subjected to a peel test. The release layer was coated to a thickness of 50 μm using a bar coater, and the solvent resistance of the adhesive layer produced by curing as described above was evaluated. The average thickness of the adhesive layer after pressure bonding was 3 μm, and the average thickness of the conductive laminated film was 50 μm.

Comparative Example 2
5 parts by weight of urethane-based laminating agent 2 and 1.66 parts by weight of curing agent were dissolved in 7.13 parts by weight of ethyl acetate to prepare laminating agent solution 2.

  On the first conductive layer in the conductive laminated film obtained in the above production example, the urethane-based laminating agent solution 2 is cured in the same manner as in Comparative Example 1 and has a 5 μm thick adhesive layer. A sheet was produced. The obtained composite encapsulating sheet was subjected to a peel test. The release layer was coated to a thickness of 50 μm using a bar coater, and the solvent resistance of the adhesive layer produced by curing as described above was evaluated. The average thickness of the adhesive layer after pressure bonding was 5 μm, and the average thickness of the conductive laminated film was 50 μm.

Comparative Example 3
An epoxy resin composition was prepared by mixing 100 parts by weight of an epoxy resin and 40 parts by weight of a curing agent.

  An epoxy resin composition is applied using an applicator on the first conductive layer in the conductive laminated film obtained in the production example, and an adhesive layer is formed. Laminate the conductive laminated film with the second conductive layer side facing the adhesive layer, and press and bond with a table laminator under the conditions of pressure 0.2 MPa and 3 m / min, and then cure at 80 ° C. for 30 minutes. And the composite sealing sheet was produced. The obtained composite encapsulating sheet was subjected to a peel test. The release layer was coated with an applicator to a thickness of 30 μm, and the solvent resistance of the adhesive layer prepared by curing as described above was evaluated. The average thickness of the adhesive layer after pressure bonding was 20 μm, and the average thickness of the conductive laminated film was 50 μm.

  Table 2 shows the evaluation results of the composite sealing sheets obtained in Examples and Comparative Examples.

  As is clear from the results in Table 2, the composite encapsulating sheets of the examples are excellent in adhesion and solvent resistance, whereas the composite encapsulating sheets of the comparative examples have low solvent resistance.

  The composite encapsulant of the present invention is used in various fields where conductivity and solvent resistance are required because different types of conductive layers are firmly bonded via an adhesive layer and have excellent solvent resistance. Applications such as containers and packaging materials for encapsulating a solvent between the first conductive layer and the second conductive layer, such as semiconductor wafer storage containers, gasoline tanks, various battery members (for example, electric two It can be used as a member such as a multilayer capacitor or a lithium ion battery. In particular, lithium ions that use polar solvents such as propylene carbonate, butylene carbonate, ethylene carbonate, methyl ethyl carbonate, diethyl carbonate, etc. to exhibit high solvent resistance even in polar solvents that are highly soluble in plastics (polymers) Suitable as a battery member, for example, a combination of a current collector and an adhesive (sealant or sealing member) (particularly a laminate of a sheet-shaped current collector and a sheet-like adhesive of a bipolar lithium ion battery). is there.

Claims (11)

  A first conductive layer formed of a cured product of a photocurable composition containing a photocurable resin and a first conductive filler, and a crystalline resin composition containing a crystalline resin and a second conductive filler The formed second conductive layer is a composite encapsulant integrated through an adhesive layer formed of an acid-modified olefin resin, and the photocurable resin is a polyfunctional vinyl having three or more functions A composite encapsulant comprising a compound and a monofunctional and / or bifunctional vinyl compound.   The composite encapsulant according to claim 1, wherein the bifunctional vinyl-based compound contains a chain aliphatic bifunctional (meth) acrylate.   The composite encapsulant according to claim 2, wherein the bifunctional vinyl compound further includes a ring-containing bifunctional (meth) acrylate having an aliphatic ring and / or an aromatic ring.   The composite encapsulant according to any one of claims 1 to 3, wherein the polyfunctional vinyl compound is 3 to 6 functional (meth) acrylate.   The composite sealing body according to claim 1, wherein the crystalline resin is a polypropylene resin.   The composite encapsulant according to any one of claims 1 to 5, wherein the first and second conductive fillers are conductive carbon black.   The composite encapsulant according to claim 1, wherein the ratio (weight ratio) between the crystalline resin and the second carbon-based conductive filler is the former / the latter = 90/10 to 55/45.   The composite sealing body according to claim 1, wherein the average thickness of the first conductive layer is 3 to 50 μm, and the average thickness of the second conductive layer is 15 to 100 μm.   The composite encapsulant according to any one of claims 1 to 8, wherein the acid-modified olefin resin is a graft copolymer of maleic anhydride.   The composite encapsulant according to claim 9, wherein the melting point of the acid-modified olefin resin is 120 to 150 ° C.   Any of Manufacturing 1 to 10 in which the same conductive layer as the second conductive layer is further stacked on the first conductive layer, and the same conductive layer as the first conductive layer is further stacked on the second conductive layer A composite encapsulant according to claim 1.