JP6484081B2 - Multilayer film for tab lead - Google Patents

Description

  The present invention relates to a laminated film for tab leads.

  2. Description of the Related Art In recent years, secondary batteries packaged in containers made of film have been used as power sources for electronic devices such as notebook computers and mobile phones, and batteries for hybrid vehicles, fuel cell vehicles, and electric vehicles.

  Conventionally, in a secondary battery, a film-like positive electrode and a negative electrode are opposed to each other via a separator, and a nonaqueous electrolyte is interposed therebetween to enable charging and discharging. Then, electricity can be taken out from the positive electrode and the negative electrode by a tab lead material made of metal. Generally, aluminum is used as the positive electrode side tab lead material, and copper is used as the negative electrode side tab lead material. These are covered with a bag made of a highly airtight laminate film in which a sealant made of polyolefin or the like is laminated on a metal foil such as aluminum foil.

  At this time, the tab lead material is bonded to the laminate film via the tab lead laminated film. The laminated film for tab leads is provided between the laminated film and the tab lead material by providing it in advance at the portion where the tab lead material and the laminated film are in contact.

  Laminate film for tab lead is adhesive for bonding metal tab lead material and laminate film, anti-electrolytic solution resistance that does not allow non-aqueous electrolyte to leak to the outside, low moisture permeability that prevents moisture from entering the inside of the battery, laminate film and tab lead There is a demand for insulation that prevents short-circuiting due to contact with the material, and adhesion to metal that the non-aqueous electrolyte does not lower the adhesion. In particular, there has been a growing demand for secondary batteries with a large capacity or large current in the last few years.

  In order to meet the demand for an increase in capacity, it is necessary to increase the size of the battery cells constituting the secondary battery. As the battery cell becomes larger, the distortion generated between the tab lead and the laminate film becomes larger than before, and the laminated film for tab lead is required to have an adhesive property that can withstand the distortion. Moreover, the non-aqueous electrolyte solution used more than before and the opportunity for the tab lead laminated film to come into contact with the electrolyte solution may increase the adhesiveness of the tab lead laminated film. For this reason, the laminated film for tab leads is required to be more resistant to electrolyte than before.

  On the other hand, it is necessary to increase the cross-sectional area (thickness) of the tab lead in order to meet the demand for a large current. When the tab lead is thickened, when the laminate film and the tab lead are bonded together by thermocompression bonding, the force generated at the corner of the tab lead is increasing, and insulation (heat resistance) that can withstand that force is required. As described above, the required level for the tab lead laminated film has increased in recent years, and the conventional tab lead laminated film cannot meet this demand.

  For example, Patent Document 1 discloses a tab lead laminated film using a heat-resistant resin layer made of 4-methyl-1-pentene resin. When a composition containing 4-methyl-1-pentene resin is used for the heat-fusible resin layer, the insulation is sufficient, but it may be easily peeled off at the interface between the tab lead and the tab lead laminated film. . Further, when a composition containing no 4-methyl-1-pentene resin is used for the heat-fusible resin layer, it may be easily peeled off at the interface between the heat-resistant resin layer and the heat-fusible resin layer. .

  In Patent Document 2, a resin obtained by blending an α-olefin polymer or the like with a copolymer of 4-methyl-1-pentene homopolymer and an α-olefin having 2 to 20 carbon atoms is used as a heat resistant resin. Although the laminated film for tab leads used for the layer is disclosed, when the α-olefin polymer is selected to ensure insulation, the adhesion is insufficient, and when the adhesion is ensured, the insulation is insufficient. It was.

  In both cases of Patent Document 1 and Patent Document 2, the adhesiveness may be lower than that in the normal state due to the influence of heat and / or electrolytic solution.

JP 2002-151023 A JP 2003-92089 A

  The required level of adhesiveness and insulation of the tab lead laminated film has increased, and it has been difficult for the conventional techniques to satisfy all the properties of adhesiveness, insulation, and electrolyte resistance.

As a result of diligent studies, the present inventor has found that the above problems can be solved by the modified polyolefin resin of the present invention. That is, the present invention has the following contents.
1) A heat-fusible resin layer (A) containing a modified polypropylene resin and an ethylene / butene resin as essential components, and a heat-sealing resin layer containing a modified polypropylene resin or a polypropylene resin and an ethylene / butene resin as essential components. A laminated film for tab leads in which a heat-resistant resin layer (C) is formed between heat-resistant resin layers (B), wherein the heat-resistant resin layer (C) contains 4-methyl-1-pentene and α-olefin. The difference between the melting point of the ethylene-butene resin and the α-olefin resin (1) of the heat-fusible resin layer (A) including the polymer and the α-olefin resin (1) having a melting point of 30 ° C. to 110 ° C. For tab lead, wherein the difference in melting point between the ethylene-butene resin and the α-olefin resin (1) of the heat-fusible resin layer (B) is within 70 ° C. Laminated film.
2) The laminated film for tab leads according to 1), wherein the α-olefin resin (1) contains either a polybutene resin or a butene / propylene resin.
3) The difference in melting point between the ethylene / butene resin and the α-olefin resin (1) of the heat-fusible resin layer (A) is within 50 ° C., and the ethylene of the heat-fusible resin layer (B) The laminated film for tab leads according to 1) or 2), wherein the difference in melting point between the butene resin and the α-olefin resin (1) is within 50 ° C.
4) Any one of 1) to 3), wherein the modified polypropylene resin is a modified polypropylene resin graft-modified using a monomer containing an ethylenic double bond and an epoxy group in the same molecule. The laminated film for tab leads described in 1.

A heat-fusible resin layer (A) comprising a modified polypropylene resin and an ethylene / butene resin as essential components, and a heat-fusible resin comprising a modified polypropylene resin or a polypropylene resin and an ethylene / butene resin as essential components. A laminated film for tab leads in which a heat resistant resin layer (C) is formed between layers (B), wherein the heat resistant resin layer (C) is a copolymer of 4-methyl-1-pentene and α-olefin. And an α-olefin resin (1) having a melting point of 30 ° C. to 110 ° C., and the difference in melting point between the ethylene butene resin and the α-olefin resin (1) of the heat-fusible resin layer is within 70 ° C. A tab lead laminated film satisfying all of the properties of adhesiveness, insulating properties, and electrolytic solution resistance can be provided by the tab lead laminated film having a certain feature.

Schematic of adhesive strength (peel strength) measurement Schematic diagram of insulation test

  An embodiment of the present invention will be described as follows. The present invention is not limited to the following description.

<Polypropylene resin>
The polypropylene resin used for the tab lead laminated film of the present invention is a resin in which 50 parts by weight or more is propylene with respect to 100 parts by weight of the monomer constituting the polypropylene resin. The polypropylene resin can include, for example, a resin obtained by copolymerization of propylene and an α-olefin having 2 to 20 carbon atoms, and can appropriately include a polyolefin resin.

  The polyolefin-based resin is a resin obtained by polymerizing a plurality of kinds of α-olefins having 2 to 20 carbon atoms. For example, polyethylene, polypropylene, poly-1-butene, polyisobutylene, random copolymer or block copolymer in any ratio of propylene and ethylene and / or 1-butene, diene component in any ratio of ethylene and propylene An ethylene-propylene-diene terpolymer having an ethylene content of 50% by weight or less, an ethylene-butene-diene terpolymer having a diene component of 50% by weight or less in any ratio of ethylene and butene, polymethylpentene, Examples thereof include cyclic polypropylenes such as a copolymer of cyclopentadiene and ethylene and / or propylene, random copolymers of ethylene or propylene and 50% by weight or less of a vinyl compound, block copolymers, and the like. Specifically, random polypropylene, block polypropylene, homopolypropylene, ethylene / propylene copolymer, ethylene / 1-butene copolymer, ethylene / 1-hexene copolymer, ethylene / 4-methylpentene-1 copolymer , Ethylene / 1-octene copolymer, propylene / ethylene copolymer, propylene / ethylene / 1-butene copolymer, 1-butene homopolymer, 1-butene / ethylene copolymer, 1-butene / propylene copolymer Polymer, 4-methylpentene-1 / propylene copolymer, 4-methylpentene-1 / 1-butene copolymer, 4-methylpentene-1 / propylene / 1-butene copolymer, propylene / 1-butene Copolymer, ethylene / vinyl acetate copolymer, ethylene / methacrylic acid copolymer, ethylene / methacrylic acid methyl It can be mentioned copolymers. Moreover, the resin which mixed these by arbitrary ratios can also be used suitably.

  As a polypropylene-based resin, it is easy to flow at the time of thermocompression bonding at 120 ° C. or higher, and at 80 ° C. or lower, the film strength of the modified polypropylene-based resin layer is maintained, so that the proportion of propylene and ethylene and / or 1-butene Random copolymers or block copolymers are preferably used.

  The melting point of the polypropylene resin is preferably 80 ° C. or higher and 180 ° C. or lower. Moreover, it is preferable that MFR in 230 degreeC and a load 2.16kg is 0.1 g / 10min or more and less than 100g / 10min, and when using it as a raw material of a modified polypropylene resin, 230 degreeC of a modified polypropylene resin and a load 2. It is preferable to use a polypropylene resin so that the MFR at 16 kg is 0.1 g / 10 min or more and less than 100 g / 10 min.

<Modified polypropylene resin>
The modified polypropylene resin used for the tab lead laminated film of the present invention is a resin obtained by graft-modifying a polypropylene resin with a compound containing an ethylenic double bond. Examples of the compound containing an ethylenic double bond include α, β-unsaturated carboxylic acid or α, β-unsaturated carboxylic acid anhydride or α, β such as acrylic acid, methacrylic acid, itaconic acid, fumaric acid, maleic acid and the like. -Unsaturated carboxylic acid esters. In particular, a compound containing an ethylenic double bond and an epoxy group in the same molecule, a modified polypropylene resin graft-modified with at least one of maleic anhydride and maleic acid is preferable in terms of increasing the adhesive strength of the metal. The modified polypropylene resin graft-modified with a compound containing a heavy bond and an epoxy group in the same molecule not only adheres to the metal, but also improves the adhesion between the heat-fusible resin layer and the heat-resistant resin layer and peels off between the layers. This is preferable in that the adhesive strength is further increased. As a compound containing an ethylenic double bond and an epoxy group in the same molecule, various compounds can be used without any particular limitation. Specific examples of such compounds include glycidyl (meth) acrylate, diglycidyl maleate, diglycidyl itaconate, diglycidyl allyl succinate, glycidyl p-styrenecarboxylate, allyl glycidyl ether, methallyl glycidyl ether, styrene-p-glycidyl. Examples include ether, p-glycidyl styrene, 3,4-epoxy-1-butene, 3,4-epoxy-3-methyl-1-butene, vinylcyclohexene monoxide, and the like. Among these, glycidyl (meth) acrylate is preferable in order to obtain adhesion with a metal material.

  Although the usage-amount of the compound containing an ethylenic double bond is not restrict | limited in particular, It is preferable that it is 0.1-10 weight part with respect to 100 weight part of polypropylene resins, and it is 0.1-7 weight part. Is more preferably 0.1 to 5 parts by weight. If it is less than 0.1 part by weight, the adhesion may not be sufficient. On the other hand, when the amount is more than 10 parts by weight, the remaining compound containing an ethylenic double bond increases, which may adversely affect the physical properties.

  When the polypropylene resin is graft-modified with a compound containing an ethylenic double bond, other monomers may be used in combination as long as the object of the present invention is not impaired. Other monomers include hydroxyl group-containing ethylenically unsaturated compounds, amino group-containing ethylenically unsaturated compounds, aromatic vinyl compounds, conjugated diene compounds, vinyl ester compounds, vinyl chloride, oxazoline group-containing unsaturated monomers. Etc.

  When aromatic vinyl compounds are used, molecular chain scission is suppressed during grafting to polypropylene and other molecular chain-breaking polypropylene, and the ethylenic double bond and epoxy group are bonded within the same molecule while maintaining a high molecular weight. It is preferable because the monomer contained in can be introduced at a high ratio.

  Examples of aromatic vinyl compounds include styrene; methyl styrene such as o-methyl styrene, m-methyl styrene, p-methyl styrene, α-methyl styrene, β-methyl styrene, dimethyl styrene, and trimethyl styrene; o-chloro. Chlorostyrenes such as styrene, m-chlorostyrene, p-chlorostyrene, α-chlorostyrene, β-chlorostyrene, dichlorostyrene, trichlorostyrene; o-bromostyrene, m-bromostyrene, p-bromostyrene, dibromostyrene, Bromostyrene such as tribromostyrene; fluorostyrene such as o-fluorostyrene, m-fluorostyrene, p-fluorostyrene, difluorostyrene, trifluorostyrene; o-nitrostyrene, m-nitrostyrene, p-nitrostyrene Nitrostyrenes such as dinitrostyrene and trinitrostyrene; vinylphenols such as o-hydroxystyrene, m-hydroxystyrene, p-hydroxystyrene, dihydroxystyrene and trihydroxystyrene; o-divinylbenzene, m-divinylbenzene and p-divinyl 1 type, or 2 or more types, such as divinylbenzene, such as benzene; diisopropenylbenzene, such as o-diisopropenylbenzene, m-diisopropenylbenzene, and p-diisopropenylbenzene; Of these, methylstyrene such as styrene, α-methylstyrene, p-methylstyrene, divinylbenzene monomer or divinylbenzene isomer mixture is preferable in that it is inexpensive. Of these, styrene is particularly preferable.

  The amount of the other monomer used is preferably 0.01 to 10 parts by weight, more preferably 0.1 to 7 parts by weight, with respect to 100 parts by weight of the polypropylene resin. More preferably, it is -5 weight part. If the amount used is too small, when a radical initiator is used in combination, the MFR (melt flow rate) of the modified polypropylene resin becomes too low, and it may be difficult to control the thickness during film formation. On the other hand, if the amount used exceeds 10 parts by weight, it depends on the amount of the compound containing an ethylenic double bond, but it is a by-product of a polymer containing an ethylenic double bond and other monomers in the system. There was a lot of things, causing fish eyes.

  A modified polypropylene resin can be obtained by heating and reacting the above polypropylene resin and a compound containing an ethylenic double bond, and if necessary, an aromatic vinyl compound in the presence of a radical initiator.

  Examples of the radical initiator include organic peroxides and azo compounds. Illustrative examples include ketone peroxides such as methyl ethyl ketone peroxide and methyl acetoacetate peroxide; 1,1-bis (t-butylperoxy) -3,3,5-trimethylcyclohexane, 1,1-bis (t- Peroxyketals such as butylperoxy) cyclohexane, n-butyl-4,4-bis (t-butylperoxy) valerate, 2,2-bis (t-butylperoxy) butane; permethane hydroperoxide, 1 , 1,3,3-tetramethylbutyl hydroperoxide, diisopropylbenzene hydroperoxide, cumene hydroperoxide, etc .; dicumyl peroxide, 2,5-dimethyl-2,5-di (t-butyl Peroxy) hexane, α, α′-bis ( -Butylperoxy-m-isopropyl) benzene, t-butylcumyl peroxide, di-t-butyl peroxide, dialkyl such as 2,5-dimethyl-2,5-di (t-butylperoxy) hexyne-3 Peroxides; diacyl peroxides such as benzoyl peroxide; peroxydicarbonates such as di (3-methyl-3-methoxybutyl) peroxydicarbonate and di-2-methoxybutylperoxydicarbonate; t-butylperoxy Octate, t-butyl peroxyisobutyrate, t-butyl peroxylaurate, t-butyl peroxy-3,5,5-trimethylhexanoate, t-butyl peroxyisopropyl carbonate, 2,5-dimethyl -2,5-di (benzoylperoxy) hexa , T- butyl peroxy acetate, t- butyl peroxybenzoate, one or more organic peroxides such as peroxy esters such as di -t- butyl peroxy isophthalate and the like.

  Of these, those having a particularly high hydrogen abstraction ability are preferred. Examples of such radical initiators include 1,1-bis (t-butylperoxy) -3,3,5-trimethylcyclohexane, 1,1- Peroxyketals such as bis (t-butylperoxy) cyclohexane, n-butyl-4,4-bis (t-butylperoxy) valerate, 2,2-bis (t-butylperoxy) butane; Oxide, 2,5-dimethyl-2,5-di (t-butylperoxy) hexane, α, α′-bis (t-butylperoxy-m-isopropyl) benzene, t-butylcumyl peroxide, di- dialkyl peroxides such as t-butyl peroxide, 2,5-dimethyl-2,5-di (t-butylperoxy) hexyne-3; Diacyl peroxides such as yl peroxide; t-butyl peroxyoctate, t-butyl peroxyisobutyrate, t-butyl peroxylaurate, t-butyl peroxy-3,5,5-trimethylhexanoate , T-butylperoxyisopropyl carbonate, 2,5-dimethyl-2,5-di (benzoylperoxy) hexane, t-butylperoxyacetate, t-butylperoxybenzoate, di-t-butylperoxyisophthalate 1 type, or 2 or more types, such as peroxyesters, etc. are mentioned.

  The addition amount of the radical initiator is preferably in the range of 0.01 to 5 parts by weight, more preferably in the range of 0.2 to 3 parts by weight with respect to 100 parts by weight of the polypropylene resin. . If it is less than 0.01 part by weight, the modification does not proceed sufficiently, and if it exceeds 5 parts by weight, fluidity and mechanical properties may be lowered.

  The reaction for graft modification is not particularly limited, and a solution reaction, an impregnation reaction, a melt reaction, and the like can be used. In particular, the melt reaction is simple and preferable.

  The melting reaction is a method in which a polypropylene resin, a radical initiator, a compound containing an ethylenic double bond, and other monomers added as necessary are kneaded while the polypropylene resin is melted.

  The heating temperature at the time of melt kneading is preferably 100 to 300 ° C. from the viewpoint that the polypropylene resin is sufficiently melted and is not thermally decomposed. The melt kneading time is usually 30 seconds to 60 minutes.

  As an apparatus for melt kneading, an extruder, a Banbury mixer, a mill, a kneader, a heating roll, or the like can be used. From the viewpoint of productivity, a method using a single-screw or twin-screw extruder is preferred. Moreover, in order to mix each material sufficiently uniformly, melt-kneading may be repeated a plurality of times.

  For modified polypropylene resins, stabilizers such as antioxidants, metal deactivators, dehydrating agents, and antacid adsorbents, or crosslinking agents, chain transfer agents, nucleating agents, lubricants, plasticizers, fillers as necessary Additives such as reinforcing materials, pigments, dyes, and flame retardants may be added within a range that does not impair the effects of the present invention. When these stabilizers and additives are used, they may be added to the polypropylene resin in advance, or added when the polypropylene resin, which is a raw material of the modified polypropylene resin, is graft-modified. Alternatively, after the modified polypropylene resin is produced, it may be added to the modified polypropylene resin by an appropriate method. The method of mixing is not particularly limited, but a method in which the modified polypropylene resin and various compounds are mixed in a tumbler, ribbon blender or the like, and when the modified polypropylene resin is produced by a melt reaction, a melt reaction is performed. Examples thereof include a method of mixing with a melt kneader.

In addition, a polypropylene resin, a polyester resin, a polystyrene resin, a polyimide resin, or the like can be mixed with the modified polypropylene resin by a convenient method.
The melting point of the modified polypropylene resin preferably includes a melting point of 80 ° C. or higher and 180 ° C. or lower. The MFR (230 ° C., load 2.16 kg) of the modified polypropylene resin is preferably 0.1 g / 10 min or more and less than 100 g / 10 min.

<Ethylene butene resin>
The ethylene / butene resin is mainly composed of a copolymer of ethylene and butene, or a resin obtained by copolymerizing 2 to 20 α-olefins appropriately with ethylene and butene, and may contain a polyolefin resin as appropriate. it can. The ethylene / butene resins include modified ethylene / butene resins. The modified ethylene / butene resin is a resin obtained by graft-modifying an ethylene / butene resin with a compound containing an ethylenic double bond. As a method for modification, the same method as that for the modified polypropylene resin can be used. By including the modified ethylene / butene resin and the ethylene / butene resin in the heat-fusible resin layer, not only the modified polypropylene resin and the polypropylene resin can be heat-sealed at a lower temperature, Adhesion between the heat-fusible resin layer and the heat-resistant resin layer is improved, and as a result, the laminate film and the tab lead material can be made difficult to peel off. The modified ethylene / butene resin and the ethylene / butene resin are preferably 5 parts by weight or more and 45 parts by weight or less, preferably 5 parts by weight or more and 40 parts by weight or less, with respect to 100 parts by weight of the resin constituting the heat-fusible resin layer. Is more preferable in terms of heat-fusibility at low temperatures and workability. When the amount is less than 5 parts by weight, not only the heat-fusibility at low temperatures is lowered, but also the adhesiveness between the heat-fusible resin layer and the heat-resistant resin is lowered, and the adhesive strength may be lowered. In the case of 45 parts by weight or more, the surface tack is large and workability may be deteriorated. The glass transition temperature of the ethylene / butene resin is preferably 30 ° C. or more and less than 100 ° C. from the viewpoint of heat fusion during low temperature processing, and 40 ° C. or more and 90 ° C. or less is more preferred from the viewpoint of workability and heat fusion. . The heat of fusion of the modified ethylene / butene resin and ethylene / butene resin in the heat-fusible resin layer is smaller than that of the modified polypropylene resin and polypropylene resin, but is preferably 1 J / g or more.

<Heat-fusion resin layer>
The heat-fusible resin layer (A) contains a modified polypropylene resin and an ethylene / butene resin as essential components. The heat-fusible resin layer (A) is in direct contact with the tab lead. On the other hand, the heat-fusible resin layer (B) contains a modified polypropylene resin or polypropylene resin and an ethylene / butene resin as essential components. The heat-fusible resin layer (B) is a layer opposite to the tab lead.
In addition to the modified polypropylene resin, polypropylene resin, and ethylene / butene resin, the heat-fusible resin layer is a synthetic resin such as polyolefin resin, polyester resin, polystyrene resin, polyimide resin, polyamide resin, or the like. Stabilizers such as antioxidants, metal deactivators, dehydrating agents, antacid adsorbents, or crosslinking agents, chain transfer agents, nucleating agents, lubricants, plasticizers, fillers, reinforcing materials, pigments, dyes, flame retardants, etc. These additives may be added within a range not impairing the effects of the present invention.

<Heat resistant resin layer>
The heat resistant resin layer of the present invention contains a heat resistant resin as a main component. The heat-resistant resin layer has a tab lead laminate film placed between the tab lead and the laminate film. When the tab lead and laminate film are heat-sealed by thermocompression bonding, the tab lead laminate film is thinned. It must be heat resistant to the extent that it does not conduct. If the heat dissipation of the tab lead and the laminate film is large, heat may be difficult to be transmitted to the tab lead laminated film, and the way heat is transferred depends on the conditions of thermocompression bonding (pressure and time). For this reason, it is necessary to consider the amount of heat transmitted to the tab lead laminated film, but in the present invention, the tab lead and the laminate film are bonded by thermocompression bonding. The heating temperature at which the tab lead and the laminate film are conducted is preferably 160 ° C. or higher, more preferably 180 ° C. or higher, and particularly preferably 200 ° C. or higher.

<Heat resistant resin>
The heat resistant resin of the present invention contains a copolymer of 4-methyl-1-pentene and α-olefin and an α-olefin resin (1). The α-olefin of the copolymer of 4-methyl-1-pentene and α-olefin contains at least one of α-olefins having 2 to 20 carbon atoms. In order to achieve both compatibility with the α-olefin resin (1) and heat resistance as the heat resistant resin layer with a single resin, the α-olefin preferably has 11 to 20 carbon atoms. 1-pentadecene, 1-hexadecene, 1-heptadecene, and 1-octadecene are preferable in terms of good compatibility with the α-olefin resin (1), and it is preferable to use both 1-hexadecene and 1-octadecene. It is further preferable in terms of good compatibility with the resin (1). On the other hand, even with a plurality of resins, compatibility with the α-olefin-based resin (1) and heat resistance as the heat-resistant resin layer can both be achieved. For example, a copolymer of 4-methyl-1-pentene and α-olefin obtained by copolymerizing 5% or more of an olefin having 2 to 8 carbon atoms of α-olefin is compatible with α-olefin resin (1). Is relatively good, but heat resistance may be low. On the other hand, a copolymer of 4-methyl-1-pentene and α-olefin obtained by copolymerizing less than 5% of α-olefin having 2 to 20 carbon atoms has high heat resistance. Therefore, a copolymer of 4-methyl-1-pentene and α-olefin obtained by copolymerizing 5% or more of an olefin having 2 to 8 carbon atoms of α-olefin, and α having 2 to 20 carbon atoms. -By mixing a copolymer of 4-methyl-1-pentene and α-olefin copolymerized with less than 5% of olefin, compatibility with α-olefin resin (1), and heat resistant resin layer It is possible to achieve both heat resistance. Use of the two types of 4-methyl-1-pentene and α-olefin copolymers balances the compatibility between the α-olefin resin (1) and the heat resistance of the heat resistant resin layer. It is preferable in that it not only removes the film, but also improves the melting characteristics and improves the workability of film processing.

  The α-olefin-based resin (1) is a resin obtained by polymerizing a plurality of α-olefins having 2 to 20 carbon atoms and having a melting point of 30 ° C. to 110 ° C. For example, polyethylene resin, polybutene resin, polyisobutylene resin, random copolymer or block copolymer in any ratio of propylene and ethylene and / or butene, random copolymerization in any ratio of butene and ethylene Copolymer or block copolymer, ethylene-propylene-diene terpolymer having a diene component of 50% by weight or less at any ratio of ethylene and propylene, diene component of 50% by weight or less at any ratio of ethylene and butene An ethylene-butene-diene terpolymer, a cyclic polypropylene such as a copolymer of cyclopentadiene and ethylene and / or propylene, a random copolymer of ethylene or propylene and a vinyl compound of 50% by weight or less, Block copolymer etc. Gerare a resin a melting point of 30 ° C. to 110 ° C.. Specifically, ethylene / propylene resin, ethylene / butene resin, ethylene / hexene resin, ethylene / octene resin, propylene / ethylene resin, propylene / ethylene / butene resin, polybutene resin, butene / ethylene Resin, butene / propylene resin, propylene / butene resin, ethylene / vinyl acetate resin, ethylene / methacrylic acid resin, ethylene / methyl methacrylate resin, and the like. Moreover, the resin which mixed these by arbitrary ratios can also be used suitably. The α-olefin-based resin (1) is an ethylene / butene copolymer, a propylene / ethylene / butene copolymer, a polybutene in terms of the compatibility of 4-methyl-1-pentene and an α-olefin copolymer. Polymer, butene / ethylene copolymer, butene / propylene copolymer, propylene / butene copolymer and melting point of 30 ° C. to 110 ° C., butene / α-olefin polymer is heat-fusible It is preferable at the point which improves adhesiveness with a resin layer. The heat-fusible resin layers (A) and (B) contain an ethylene / butene-based resin. Therefore, the heat-resistant resin layer (C) containing a polymer of butene and α-olefin is heat-fusible. By improving the adhesion with the resin layers (A) and (B), it becomes difficult to peel off between the layers. As a result, the adhesive strength between the laminate film and the tab lead can be increased. When the α-olefin resin (1) is a polybutene resin or a butene / propylene resin, it is particularly preferable from the viewpoint of improving the resistance to electrolytic solution.

  When the resin constituting the heat-resistant resin layer is 100 parts by weight, the copolymer of 4-methyl-1-pentene and α-olefin is 40 parts by weight or more and 90 parts by weight or less, and the α-olefin resin (1) Is preferably 10 parts by weight or more and 60 parts by weight or less.

  The melting point of the α-olefin resin (1) is 30 ° C. to 110 ° C. When the melting point of the α-olefin-based resin (1) is less than 30 ° C., the tackiness of the pellet surface obtained by melt-kneading becomes high and handling may be difficult. In addition, when the melting point of the α-olefin resin (1) is higher than 110 ° C., the crystallization of the α-olefin resin (1) is likely to partially proceed, and the characteristic variation in the plane of the tab lead laminated film. Sometimes increased.

  Using a copolymer of 4-methyl-1-pentene and α-olefin and an α-olefin resin (1) for the heat resistant resin layer, the melting point of the α-olefin resin (1) and the heat-fusible resin layer ( A) Adhesion between the heat-fusible resin layers (A) and (B) and the heat-resistant resin layer (C) by making the difference in melting points of the ethylene / butene resins contained in (B) within 70 ° C. It became possible to improve. Thereby, peeling between the layers of the heat-fusible resin layers (A) and (B) and the heat-resistant resin layer (C) was suppressed, and as a result, the adhesive strength between the laminate film and the tab lead could be increased. When the difference between the melting point of the α-olefin resin (1) and the melting point of the ethylene butene resin contained in the heat-fusible resin layers (A) and (B) is higher than 70 ° C., the adhesive strength between the laminate film and the tab lead May decrease. Reducing the difference between the melting point of the α-olefin resin (1) and the melting point of the ethylene / butene resin contained in the heat-fusible resin layers (A) and (B) means that each component melts at a close temperature. In addition, the temperature at which solidification (crystallization) takes place becomes closer. Therefore, the mutual components are taken in at the interface between the heat-fusible resin layers (A) and (B) and the heat-resistant resin layer (C), and the heat-fusible resin layers (A) and (B) and the heat-resistant resin layers (A) and (B) are heat-resistant. It is estimated that peeling between the resin layers (C) can be suppressed. The effect becomes remarkable when the laminated film for tab leads is formed by coextrusion. The difference between the melting point of the α-olefin-based resin (1) and the melting point of the ethylene / butene-based resin contained in the heat-fusible resin layers (A) and (B) is preferably within 50 ° C. from the viewpoint of increasing the adhesive strength. . As described above, it is possible to increase the adhesive strength after annealing and after immersion in the electrolytic solution.

  Copolymer of 4-methyl-1-pentene and α-olefin and α-olefin resin (1) used for heat resistant resin is a compound containing an ethylenic double bond in the same manner as the modified polypropylene resin Can be graft modified. Moreover, it is also possible to melt knead after graft-modifying either 4-methyl-1-pentene and α-olefin copolymer or α-olefin resin (1) with a compound containing an ethylenic double bond. it can.

  In addition to 4-methyl-1-pentene and α-olefin copolymer and α-olefin resin (1), the heat resistant resin is polyolefin resin, polyester resin, polystyrene resin, polyimide resin, polyamide resin. Synthetic resins such as antioxidants, stabilizers such as antioxidants, metal deactivators, dehydrating agents, antacid adsorbents, or crosslinking agents, chain transfer agents, nucleating agents, lubricants, plasticizers, fillers, reinforcing materials, pigments Additives such as dyes and flame retardants may be added within a range not impairing the effects of the present invention.

<Laminated film for tab lead>
The laminated film for tab leads has a three-layer structure in which a heat resistant resin layer (C) is sandwiched between a heat fusible resin layer (A) and a heat fusible resin layer (B). Although the manufacturing method is not particularly limited, after the heat-resistant resin layer (C) is obtained as a film, the heat-fusible resin layer (A) and the heat-fusible resin layer (B) can be laminated by extrusion lamination. It is. Moreover, it can also manufacture by coextrusion which extrudes a heat-fusible resin layer (A), a heat-resistant resin layer (C), and a heat-fusible resin layer (B) simultaneously. The laminated film for tab lead in the present invention improves the adhesion between the heat-fusible resin layers (A) and (B) and the heat-resistant resin layer (C). It became possible to obtain a highly reliable laminated film for tab leads that is difficult to peel off. The copolymer of 4-methyl-1-pentene and α-olefin has a high releasability, and may be easily peeled off even if a heat-fusible resin layer is laminated. When the laminated film for tab leads is produced by coextrusion, the MFR (measuring temperature 260 ° C., load 2) of the heat-fusible resin layer (A), the heat-fusible resin layer (B), and the heat-resistant resin layer (C). 16 kg) is preferably 3 g / 10 min or more and less than 50 g / 10 min, more preferably 5 g / 10 min or more and 40 g / 10 min or less. When the MFR is less than 3 g / 10 min, a melt fracture may be easily formed. Further, when the MFR is 50 g / 10 min or more, the thickness unevenness in the width direction of the tab lead laminated film may become large. The MFR of the heat-fusible resin layers (A) and (B) at the film forming temperature is 0.5 times or more and less than 2 times the MFR of the heat-resistant resin layer (C). This is preferable in terms of reducing unevenness and stabilizing characteristics.

The thickness and width of the tab lead laminated film are not particularly limited as long as there is no practical problem, but the thickness is preferably 50 μm or more and less than 300 μm, and the width is preferably 3 mm or more and less than 30 mm. A narrow tab lead laminated film can be obtained by slitting a wide tab lead laminated film.
The adhesive strength of the tab lead laminated film is preferably 30 N / 15 mm or more, and more preferably 40 N / 15 mm or more.

<Lamination method of tab lead laminated film to tab lead>
The laminated film for tab lead is bonded to the tab lead. At the time of bonding, it is necessary to bond so that the modified polyolefin resin layer is in contact with the tab lead. The method of bonding is not particularly limited, but it is preferable to bond the tab lead laminated film to the tab lead by thermocompression bonding.

<Lamination film and tab lead bonding method>
The laminate film and the tab lead are bonded together with an adhesive layer inside the laminate film and a laminated film for tab lead. In general, the bonding method is thermocompression bonding.

  EXAMPLES Hereinafter, although an Example demonstrates this invention further more concretely, this invention is not limited at all by these Examples.

<Melting point measurement>
After forming a resin with a film forming temperature of 260 ° C. and a T-die film having a thickness of 100 μm, the film was stored at 23 ° C. and 55% for 72 hours. Thereafter, the melting point was measured using DSC Q1000 (manufactured by TA Instruments). Measurement conditions were as follows: after cooling from room temperature to −20 ° C., a temperature range of −20 ° C. to 250 ° C. was measured at a temperature rising rate of 10 ° C./min to calculate the melting point. The melting point is the first measurement result.

<Adhesive strength measurement>
The laminate film is formed by laminating a nylon film (thickness: 25 μm) on one side of a chemically treated aluminum foil (thickness: 40 μm), and a modified polypropylene resin and a polypropylene film (thickness) on the other side of the aluminum foil. 30 μm) were stacked in that order. A heat-sealable resin layer of a laminated film for tab leads (length 25 mm × width 25 mm) between the laminate film (length 100 mm × width 25 mm) and a chromated aluminum plate (thickness 100 μm, length 50 mm × width 25 mm) (B) Place the side on the laminate film side and heat laminate once at a linear speed of 0.5 m / min with a simple laminating machine (Lamipacker LPD3226 Meister6 manufactured by Fuji Plastic Co., Ltd.) set at 150 ° C. It was. Then, this was press-bonded with a heat seal tester TP-701-B (tester industry) at 200 ° C. (up and down heating) for 10 seconds at 0.5 MPa to prepare a measurement sample. A PET film (thickness: 25 μm) between the laminate film and the aluminum plate in order to prevent the laminate film and the aluminum plate from directly sticking at the portion where there is no tab lead laminated film during the temporary compression bonding and the main compression bonding. ) Was placed.
The adhesive strength is determined by bonding the aluminum plate side of the measurement sample to a SUS plate (thickness: 1 mm) with an adhesive, then pulling the laminate film in the 180 ° direction at a traverse speed of 50 mm / min, and removing the peel strength. It was measured. The value of the peel strength width (horizontal) in terms of 15 mm was defined as the adhesive strength.

  The normal adhesive strength was measured after storing the measurement sample at 23 ° C. and 55% RH for 24 hours. The adhesive strength after annealing was measured within 2 hours after the measurement sample was stored at 80 ° C. for 24 hours. The adhesive strength after immersion in the electrolytic solution is that after being stored in an electrolytic solution (EC: PC: DEC (25: 5: 70 v / v%) (Kishida Chemical) at 80 ° C. for 24 hours, it is washed with the electrolytic solution. The adhesive strength was measured within 2 hours.

<Insulation test>
In order to evaluate the insulating properties of the tab lead laminated film alone, an aluminum foil was used instead of the laminated film. A tab lead laminated film (length 35 mm x width 25 mm) is placed between an aluminum foil (thickness 40 μm, length 50 mm × width 50 mm) and a chromate-treated aluminum plate (thickness 100 μm, length 50 mm × width 15 mm), and aluminum. A tester was connected between the foil and the aluminum plate. After that, with a heat seal tester TP-701-B (tester industry), the pressure was changed to 160 ° C, 180 ° C and 200 ° C with a pressure of 0.5 MPa and a time of 60 seconds, and the resistance value was greatly increased. The maximum temperature that did not decrease was measured.

<Tack evaluation>
Resin is put into the hopper of a single screw extruder (product name: Labo Plast Mill; φ20mm, L / D = 20) set at a cylinder and die temperature of 200 to 250 ° C. and a screw speed of 100 rpm, and attached to the tip of the die. From the T-shaped die, the melt was dropped onto a metallic cooling roll in a mirror state. Thereafter, the number of rotations of the cooling roll was controlled to obtain a film having a thickness of 100 μm. The cylinder and die temperature were set to temperatures at which a film having a thickness of 100 μn was obtained while observing the melted state of the melt.
The obtained film put the surfaces in contact with the cooling rolls together, applied a 2 kg load, and pressed the film once with the rolls. Thereafter, “◯” indicates that the films are not attached to each other, “△” indicates that the films are not attached, and “x” indicates that the films are attached.

<MFR measurement>
The amount of resin flowing for 10 minutes was measured with a melt indexer under measurement conditions of 230 ° C. or 260 ° C. and a load of 2.16 kg.

<Modified polypropylene resin, polypropylene resin>
The resin component and its ratio (parts by weight) were changed to obtain a modified polypropylene resin and a polypropylene resin. Tables 1 and 2 show the resin components and their ratios.

● Modified PP-1 (X / Y)
Polypropylene resin containing a small amount of ethylene (melting point: 124 ° C., MFR (230 ° C.): 7 g / 10 min) and X part by weight of ethylene / butene resin (melting point: 50 ° C., MFR (100 parts by weight) with respect to 100 parts by weight of the resin component. 230 ° C.): 7 g / 10 min) of Y parts by weight and 0.7 parts by weight of 1,3-di (t-butylperoxyisopropyl) benzene (manufactured by NOF: Perbutyl P, half-life 175 ° C. for 1 minute) After supplying from a mouth to a twin screw extruder (Nippon Steel Works, product name LABOTEX30; φ30 mm, L / D = 28) set to a cylinder temperature of 220 ° C. and a screw rotation speed of 150 rpm, melt and knead, then styrene from the middle of the cylinder 4 parts by weight and 4 parts by weight of glycidyl methacrylate were added, and after melt-kneading and deaeration, the strands were cooled with water and then cut to obtain a modified polymer. A pellet of a propylene resin (modified PP-1 (X / Y)) was obtained. When the pellet was used as a film and the melting point was measured, peaks of 3 J / g at 50 ° C. and 34 J / g at 124 ° C. were observed.

● Modified PP-2 (X / Y)
Polypropylene resin containing a small amount of ethylene (melting point: 124 ° C., MFR (230 ° C.): 7 g / 10 min) and X part by weight of ethylene / butene resin (melting point: 50 ° C., MFR (100 parts by weight) with respect to 100 parts by weight of the resin component. 230 ° C.): 7 g / 10 min) of Y part by weight, 1,3-di (t-butylperoxyisopropyl) benzene (manufactured by NOF: Perbutyl P, 1 minute half-life 175 ° C.) 0.7 part by weight, anhydrous After supplying 4 parts by weight of maleic acid from a hopper port to a twin screw extruder (manufactured by Nippon Steel Works, product name LABOTEX30; φ30 mm, L / D = 28) set to a cylinder temperature of 220 ° C. and a screw rotation speed of 250 rpm. Next, 4 parts by weight of styrene was added from the middle of the cylinder, melt kneading and deaeration were performed, and then the strand was cooled with water and cut to obtain a modified polypropylene. Pellets of resin (modified PP-2 (X / Y)) were obtained.

● Modified PP-3 (X / Y)
Except for using ethylene butene resin (melting point: 72 ° C., MFR (230 ° C.): 7 g / 10 min) instead of ethylene butene resin (melting point: 50 ° C., MFR (230 ° C.): 7 g / 10 min). Obtained in the same manner as modified PP-1 (X / Y).

● Modified PP-4 (X / Y)
Except for using ethylene butene resin (melting point: 30 ° C., MFR (230 ° C.): 7 g / 10 min) instead of ethylene butene resin (melting point: 50 ° C., MFR (230 ° C.): 7 g / 10 min). Obtained in the same manner as modified PP-1 (X / Y).

PP-1 (X / Y)
From 100 parts by weight of the resin component, X parts by weight of a polypropylene resin containing a small amount of ethylene and Y parts by weight of ethylene butene resin (melting point: 50 ° C., MFR (230 ° C.): 7 g / 10 min) from the hopper port. Supply to a twin-screw extruder (Nippon Steel Works, product name: LABOTEX30; φ30 mm, L / D = 28) set at a cylinder temperature of 220 ° C. and a screw rotation speed of 250 rpm, and then melt-knead and deaerate, then water-cool and polyolefin Pellets of resin based (PP-1 (X / Y)) were obtained.

<Heat resistant resin>
The resin component and ratio of 4-methyl-1-pentene and α-olefin copolymer and α-olefin resin (1) were changed to obtain a heat resistant resin. Table 3 shows the resin components and their ratios.

● HR-1
80 parts by weight of a copolymer of 4-methyl-1-pentene, hexadecene and octadecene (melting point: 227 ° C., MFR (260 ° C.): 3 g / 10 min) with respect to 100 parts by weight of the resin component, and a polybutene resin ( Melting point: 90 ° C., MFR (230 ° C.): 7 g / 10 min) 20 parts by weight of twin screw extruder set at cylinder temperature 270 ° C. and screw rotation speed 150 rpm from the hopper port (manufactured by Nippon Steel, product name LABOTEX 30; φ30 mm, L / D = 28), melt kneading and deaeration were performed, and then the strand was cooled with water and cut to obtain pellets of heat resistant resin (HR-1). At that time, 1,3-di (t-butylperoxyisopropyl) benzene (manufactured by NOF Corporation: perbutyl P, half-life 175 ° C.) so that the MFR (260 ° C.) of the resin is 20 g / 10 min. The amount added was adjusted.

● HR-2
60 parts by weight of a copolymer of 4-methyl-1-pentene, hexadecene and octadecene (melting point: 227 ° C., MFR (260 ° C.): 3 g / 10 min) with respect to 100 parts by weight of the resin component, butene / propylene system The resin (melting point: 93 ° C., MFR (230 ° C.): 7 g / 10 min) was used in the same manner as HR-1 using 40 parts by weight.

● HR-3
For 100 parts by weight of the resin component, 60 parts by weight of a copolymer of 4-methyl-1-pentene, hexadecene and octadecene (melting point: 227 ° C., MFR (260 ° C.): 3 g / 10 min), polybutene resin ( Melting point: 50 ° C., MFR (230 ° C.): 7 g / 10 min) using 20 parts by weight, polypropylene resin (melting point: 165 ° C., MFR (230 ° C.): 7 g / 10 min) using 20 parts by weight, similar to HR-1 Obtained.

● HR-4
60 parts by weight of a copolymer of 4-methyl-1-pentene and decene (melting point: 237 ° C., MFR (260 ° C.): 3 g / 10 min) with respect to 100 parts by weight of the resin component, and 4-methyl-1- 10 parts by weight of a copolymer of pentene and propylene (melting point: 180 ° C.) and 30 parts by weight of a polybutene resin (melting point: 90 ° C., MFR (230 ° C.): 7 g / 10 min) are used in the same manner as in HR-1. Obtained.

● HR-5
40 parts by weight of 4-methyl-1-pentene and decene copolymer (melting point: 237 ° C., MFR (260 ° C.): 3 g / 10 min) with respect to 100 parts by weight of the resin component, and 4-methyl-1- 10 parts by weight of a copolymer of pentene and propylene (melting point: 180 ° C.), 50 parts by weight of butene / propylene resin (melting point: 93 ° C., MFR (230 ° C.): 7 g / 10 min), (T-Butylperoxyisopropyl) benzene (manufactured by NOF: Perbutyl P, half-life of 175 ° C for 1 minute) A twin screw extruder (set at 0.3 parts by weight from the hopper port at a cylinder temperature of 270 ° C and a screw speed of 250 rpm) Supplied to Nippon Steel Works, product name LABOTEX30; φ30mm, L / D = 28), melt-kneaded, and then 2 parts by weight of styrene, glycidylmeta from the middle of the cylinder After adding 2 parts by weight of acrylate, melt kneading and deaeration were performed, and then the strand was cooled with water and cut to obtain pellets of a modified heat resistant resin (HR-5). The MFR (260 ° C.) of the resin was 20 g / 10 min.

● HR-6
For 100 parts by weight of the resin component, 60 parts by weight of a copolymer of 4-methyl-1-pentene, hexadecene and octadecene (melting point: 227 ° C., MFR (260 ° C.): 3 g / 10 min), polybutene resin ( Melting point: 100 ° C., MFR (230 ° C.): 7 g / 10 min) using 20 parts by weight, polypropylene resin (melting point: 165 ° C., MFR (230 ° C.): 7 g / 10 min) using 20 parts by weight, similar to HR-1 Obtained.

● HR-7
A copolymer of 4-methyl-1-pentene, hexadecene and octadecene (melting point: 227 ° C., MFR (260 ° C.): 3 g / 10 min) is used in the same manner as HR-1 with respect to 100 parts by weight of the resin component. Obtained.

● HR-8
60 parts by weight of a copolymer of 4-methyl-1-pentene, pentene and decene (melting point: 237 ° C., MFR (260 ° C.): 3 g / 10 min) with respect to 100 parts by weight of the resin component, polypropylene resin (melting point) : 124 ° C., MFR (230 ° C.): 7 g / 10 min) was used in the same manner as HR-1 using 40 parts by weight.

● HR-9
For 100 parts by weight of the resin component, 60 parts by weight of a copolymer of 4-methyl-1-pentene, hexadecene and octadecene (melting point: 227 ° C., MFR (260 ° C.): 3 g / 10 min), polyethylene resin ( 40 parts by weight of a melting point: 110 ° C. was obtained in the same manner as in HR-1.

Example 1
A single screw extruder (φ20 mm, L / D = 25) (A) (B) (C) is connected to a three-layer extrusion die (width 200 mm, lip clearance 0.6 mm), and a heat-fusible resin layer (A) Modified PP-1 (80/20) pellets to the single screw extruder (A) connected to the, and modified PP-1 (80/20) to the single screw extruder (B) connected to the heat-fusible resin layer (B) HR-1 pellets are put into a single screw extruder (C) connected to the pellets and the heat-resistant resin layer (C), and the cylinder, the adapter where the resin joins, and the three-layer extrusion die at 260 ° C. at 260 ° C. And cooled with a metal cooling roll to obtain a three-layer film. The three-layer film had a three-layer structure of heat-sealable resin layer (A) / heat-resistant resin layer (C) / heat-sealable resin layer (B). Thereafter, it was slit to a width of 25 mm to obtain a tab lead laminated film. The thickness of the tab lead laminated film was 100 μm, the thickness of the heat-fusible resin layers (A) and (B) was 35 μm, and the thickness of the heat-resistant resin layer (C) was 30 μm. Table 4 summarizes the evaluation of adhesive strength (normal state, after annealing, after immersion in electrolytic solution), insulation, and tack.

(Example 2)
The same procedure as in Example 1 was conducted except that the modified PP-1 (70/30) was added to the single screw extruder (A) (B) and HR-2 was charged to the single screw extruder (C). Table 4 summarizes the evaluation of adhesive strength (normal state, after annealing, after immersion in electrolytic solution), insulation, and tack.

(Example 3)
Other than charging modified PP-1 (70/30) into single screw extruder (A), PP-1 (70/30) into single screw extruder (B), and HR-3 into single screw extruder (C) Was the same as in Example 1. Table 4 summarizes the evaluation of adhesive strength (normal state, after annealing, after immersion in electrolytic solution), insulation, and tack.

Example 4
The same procedure as in Example 1 was conducted except that the modified PP-3 (70/30) was added to the single screw extruder (A) (B) and HR-4 was charged to the single screw extruder (C). Table 4 summarizes the evaluation of adhesive strength (normal state, after annealing, after immersion in electrolytic solution), insulation, and tack.

(Example 5)
The same procedure as in Example 1 was performed except that the modified PP-2 (80/20) was added to the single screw extruder (A) (B) and HR-5 was charged to the single screw extruder (C). Table 4 summarizes the evaluation of adhesive strength (normal state, after annealing, after immersion in electrolytic solution), insulation, and tack.

(Example 6)
The same procedure as in Example 1 was performed except that the modified PP-1 (50/50) was added to the single screw extruder (A) (B) and HR-1 was charged to the single screw extruder (C). Table 4 summarizes the evaluation of adhesive strength (normal state, after annealing, after immersion in electrolytic solution), insulation, and tack.

(Example 7)
The same procedure as in Example 1 was conducted except that modified PP-4 (55/45) was added to the single screw extruder (A) (B) and HR-6 was charged to the single screw extruder (C). Table 4 summarizes the evaluation of adhesive strength (normal state, after annealing, after immersion in electrolytic solution), insulation, and tack.

(Comparative Example 1)
The same procedure as in Example 1 was conducted except that the modified PP-2 (80/20) was added to the single screw extruder (A) (B) and HR-7 was charged to the single screw extruder (C). Table 5 summarizes the evaluation of adhesive strength (normal state, after annealing, after immersion in electrolytic solution), insulation, and tack.

(Comparative Example 2)
The same procedure as in Example 1 was conducted except that the modified PP-1 (70/30) was added to the single screw extruder (A) (B) and HR-8 was charged to the single screw extruder (C). Table 5 summarizes the evaluation of adhesive strength (normal state, after annealing, after immersion in electrolytic solution), insulation, and tack.

(Comparative Example 3)
The same procedure as in Example 1 was conducted except that the modified PP-1 (100/0) was added to the single screw extruder (A) (B) and HR-10 was charged to the single screw extruder (C). Table 5 summarizes the evaluation of adhesive strength (normal state, after annealing, after immersion in electrolytic solution), insulation, and tack.

(Comparative Example 4)
The same procedure as in Example 1 was conducted except that modified PP-4 (55/45) was added to the single screw extruder (A) (B) and HR-9 was charged to the single screw extruder (C). Table 5 summarizes the evaluation of adhesive strength (normal state, after annealing, after immersion in electrolytic solution), insulation, and tack.

Claims (4)

  A heat-fusible resin layer (A) comprising a modified polypropylene resin and an ethylene / butene resin as essential components, and a heat-fusible resin comprising a modified polypropylene resin or a polypropylene resin and an ethylene / butene resin as essential components. A laminated film for tab leads in which a heat resistant resin layer (C) is formed between layers (B), wherein the heat resistant resin layer (C) is a copolymer of 4-methyl-1-pentene and α-olefin. And an α-olefin resin (1) having a melting point of 30 ° C. to 110 ° C., and the difference in melting point between the ethylene butene resin and the α-olefin resin (1) of the heat-fusible resin layer (A) is 70. A laminated film for tab leads, wherein the difference in melting point between the ethylene-butene resin and the α-olefin resin (1) of the heat-fusible resin layer (B) is within 70 ° C. .   The laminated film for tab leads according to claim 1, wherein the α-olefin resin (1) contains either a polybutene resin or a butene / propylene resin. The difference in melting point between the ethylene-butene resin and the α-olefin resin (1) of the heat-fusible resin layer (A) is within 50 ° C., and the ethylene-butene of the heat-fusible resin layer (B) The laminated film for tab leads according to claim 1 or 2, wherein the difference between the melting points of the resin and the α-olefin resin (1) is within 50 ° C.   The modified polypropylene resin is a modified polypropylene resin graft-modified with a monomer containing an ethylenic double bond and an epoxy group in the same molecule, according to any one of claims 1 to 3. The laminated film for tab leads as described.