Laminate, method for producing the same, and battery pack

Abstract

To provide a laminate that exhibits high adhesive strength and superior sealing performance, and allows for material recycling.SOLUTION: A laminate comprises a thermoplastic elastomer layer on one side of a plate including a synthetic resin, wherein the thermoplastic elastomer layer is in direct contact with the plate, the thermoplastic elastomer layer is composed of a material containing either or both of an olefin-based rubber and a polyolefin-based resin, the thermoplastic elastomer layer constitutes an area of 90% or less relative to a surface area of the plate, and the maximum-to-minimum thickness gap in the thermoplastic elastomer layer is 1.5 mm or less.SELECTED DRAWING: None

Description

Technical Field

[0001] The present invention relates to a laminate, a method for manufacturing the same, and a battery pack.

Background Art

[0002] Conventionally, a battery pack in which a power storage unit is disposed in a case has been known (see, for example, Patent Documents 1 and 2).

[0003] The case includes an upper case and a lower case. The upper case has an upper case body formed in a toped cylindrical shape and an upper flange protruding outward from the outer peripheral edge of the lower end portion of the upper case body. The lower case has a lower case body formed in a bottomed cylindrical shape and a lower flange protruding outward from the outer peripheral edge of the upper end portion of the lower case body. The upper flange of the upper case is disposed so as to face the lower flange of the lower case. A predetermined power is stored in the power storage unit. The power storage unit is disposed in the upper case body and the lower case body.

[0004] Also, a sealing material is used between the upper flange and the lower flange (see, for example, Patent Document 1). The sealing material is used for waterproof and dustproof purposes, is flexible, and vulcanized rubber is used as a member that requires rubber elasticity.

[0005] In recent years, as part of environmental measures, research and development of electric vehicles and hybrid vehicles have been promoted, and development and weight reduction of high-energy density batteries aiming at improving the cruising range have been actively carried out. Such high-energy density batteries may catch fire due to an accidental accident, and since the case requires high flame retardancy as a safety measure for passengers, a metal material and a refractory material are often used in combination. However, metal materials have the drawback of being heavy, and when used in combination with refractory materials, cost increases due to workability and an increase in the number of parts have become issues. Therefore, resinification that has the potential to achieve both weight reduction and flame shielding properties has been attempted (see, for example, Patent Document 3).

Prior Art Documents

Patent Documents

[0006]

Patent Document 1

Patent Document 2

Patent Document 3

Summary of the Invention

Problems to be Solved by the Invention

[0007] Currently, towards a sustainable society, suppression of carbon dioxide and recyclability have been emphasized. However, the vulcanized rubber conventionally used as a sealing material has problems such as being difficult to recycle materials. In addition, as a method of fixing a sealing material to the flange portion of a case, generally, the flange and the vulcanized rubber are adhered with an adhesive layer such as a double-sided tape. In such a case, the adhesive strength may not be sufficient. In addition, the sealing performance may be impaired by passing through an adhesive layer such as a double-sided tape.

[0008] Therefore, the present invention has been made in view of such problems, and an object thereof is to provide a laminate having high adhesive strength, excellent sealing performance, and capable of material recycling.

Means for Solving the Problems

[0009] In order to solve the above problems, the present invention proposes the following means. (1)Aspect 1 of the present invention is a laminate having a thermoplastic elastomer layer on one side of a plate containing a synthetic resin, wherein the thermoplastic elastomer layer is in direct contact with the plate, the thermoplastic elastomer layer is formed of a material containing either or both of an olefin rubber or a polyolefin resin, the thermoplastic elastomer layer occupies an area of 90% or less with respect to the surface area of the plate, and the difference between the maximum thickness and the minimum thickness in the thermoplastic elastomer layer is 1.5 mm or less.

[0010] (2)Aspect 2 of the present invention may be the laminate according to (1), wherein the thickness of the thermoplastic elastomer layer is 10 mm or less. (3)Aspect 3 of the present invention may be the laminate according to (1) or (2), wherein the synthetic resin contains a thermoplastic resin. (4)Aspect 4 of the present invention may be the laminate according to any one of (1) to (3), wherein the synthetic resin contains a polyolefin resin. (5)Aspect 5 of the present invention may be the laminate according to any one of (1) to (4), wherein the plate is formed of a resin fiber composite material in which fibers are mixed with a synthetic resin. (6)Aspect 6 of the present invention may be the laminate according to (5), wherein the fibers contain glass fibers. (7)Aspect 7 of the present invention may be the laminate according to (5) or (6), wherein the resin fiber composite material is a stampable sheet. (8)Aspect 8 of the present invention may be a method for manufacturing the laminate according to any one of (1) to (7), wherein the thermoplastic elastomer layer is heat-sealed to the plate. (9)Aspect 9 of the present invention may be a method for manufacturing the laminate according to any one of (1) to (7), wherein the thermoplastic elastomer layer is formed by a three-dimensional laminating and shaping method. (10)Aspect 10 of the present invention may be a battery pack using the laminate according to any one of (1) to (7).

Advantages of the Invention

[0011] The laminate of the present invention has high adhesive strength, excellent sealing properties, and is capable of material recycling.

Brief Description of the Drawings

[0012]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Figure 6

Modes for Carrying Out the Invention

[0013] Next, an example of an embodiment of the present invention will be described. However, the present invention is not limited to the embodiments described below.

[0014] <<Laminate>> The laminate of the present invention (hereinafter, also referred to as "the present laminate") includes a thermoplastic elastomer layer on one side of a plate containing a synthetic resin. That is, the present laminate includes a plate containing a synthetic resin and a thermoplastic elastomer layer on one side of the plate containing a synthetic resin.

[0015] <Plate Containing Synthetic Resin> The present laminate includes a plate containing a synthetic resin. Examples of the resin used for the synthetic resin include thermoplastic resins, thermosetting resins, and elastomer resins. Examples of the thermoplastic resin include polyolefin resins such as polypropylene resin, polyethylene resin, poly(1-)butene resin, and polypentene resin; polyester resins such as polyethylene terephthalate; polystyrene resin; acrylonitrile-butadiene-styrene (ABS) resin; polyvinyl acetal resin; ethylene-vinyl acetate copolymer (EVA) resin; polyvinyl alcohol resin; polycarbonate resin; polyphenylene ether resin; acrylic resin; polyamide resin; polyvinyl chloride resin (PVC); novolak resin; polyurethane resin; and polyisobutylene resin. Examples of the thermosetting resin include epoxy resin, vinyl ester resin, urethane resin, phenol resin, urea resin, melamine resin, unsaturated polyester resin, and polyimide resin. Examples of the elastomer resin include acrylonitrile-butadiene rubber, ethylene-propylene-diene rubber (EPDM), ethylene-propylene rubber, natural rubber, polybutadiene rubber, polyisoprene rubber, styrene-butadiene block copolymer, hydrogenated styrene-butadiene block copolymer, hydrogenated styrene-butadiene-styrene block copolymer, hydrogenated styrene-isoprene block copolymer, and hydrogenated styrene-isoprene-styrene block copolymer. The synthetic resin may be a single resin or a composite resin of two or more kinds.

[0016] The content of the synthetic resin in the plate is not particularly limited, but is preferably 15 to 80% by mass. When the content of the synthetic resin is 15% by mass or more, the moldability is good, and when it is 80% by mass or less, a sufficient amount of other components (flame retardants, dispersants, fibers, etc., described later) can be contained, and for example, good flame shielding properties can be obtained. From the above viewpoints, the content of the synthetic resin is more preferably 35 to 70% by mass, and even more preferably 40 to 60% by mass.

[0017] Among them, from the perspective of recyclability, it is preferable to include a thermoplastic resin as the synthetic resin. The overall melt flow rate (MFR) of the thermoplastic resin is preferably 40 to 500 g / 10 min. If the MFR is 40 g / 10 min or more, the processability will not decrease. Also, if it is 500 g / 10 min or less, burrs will not occur. From the above perspectives, the MFR is more preferably 50 to 400 g / 10 min, still more preferably 60 to 400 g / 10 min, and particularly preferably 70 to 300 g / 10 min. The MFR of the thermoplastic resin can be adjusted, for example, by controlling the hydrogen concentration during polymerization. The MFR is measured in accordance with JIS K7210 under the conditions of a temperature of 230°C and a load of 2.16 kg.

[0018] More preferably, the thermoplastic resin includes a polyolefin resin. That is, it is more preferable to include a polyolefin resin as the synthetic resin. In the present invention, the "polyolefin resin" means a resin in which the proportion of olefin units or cycloolefin units is 90 mol% or more with respect to 100 mol% of all the constituent units constituting the resin. The proportion of olefin units or cycloolefin units with respect to 100 mol% of all the constituent units constituting the polyolefin resin is preferably 95 mol% or more, and more preferably 98 mol% or more. Examples of polyolefin resins include α-olefin polymers such as polyethylene, polypropylene, polybutene, poly(3-methyl-1-butene), poly(3-methyl-1-pentene), poly(4-methyl-1-pentene), etc.; α-olefin copolymers such as ethylene-propylene block or random copolymers, α-olefin-propylene block or random copolymers having 4 or more carbon atoms, ethylene-methyl methacrylate copolymers, ethylene-vinyl acetate copolymers, etc.; cycloolefin polymers such as polycyclohexene, polycyclopentene, etc. Examples of polyethylene include low-density polyethylene, linear low-density polyethylene, high-density polyethylene, etc. Examples of polypropylene include isotactic polypropylene, syndiotactic polypropylene, hemi-isotactic polypropylene, stereoblock polypropylene, etc. In the α-olefin-propylene block or random copolymer having 4 or more carbon atoms, examples of the α-olefin having 4 or more carbon atoms include butene, 3-methyl-1-butene, 3-methyl-1-pentene, 4-methyl-1-pentene, etc. These polyolefin resins may be used alone or in combination of two or more.

[0019] From the viewpoint of recyclability, the polyolefin resin preferably contains polypropylene. Polypropylene may be used in combination with other polyolefin resins. For example, as the polyolefin resin, a mixture of polypropylene and other α-olefin polymers such as ethylene-propylene block or random copolymer, α-olefin-propylene block or random copolymer having 4 or more carbon atoms may be used. The polyolefin resin preferably has polypropylene as the main component. The proportion of polypropylene in the polyolefin resin (100% by mass) is preferably 50% by mass or more, more preferably 60% by mass or more.

[0020] A board containing a synthetic resin preferably contains a flame retardant for the purpose of improving the flame shielding property. The flame retardant is not particularly limited, and examples thereof include phosphorus-based flame retardants, bromine-based flame retardants, and antimony-based flame retardants. Among them, from the viewpoint of improving the flame shielding property, a phosphorus-based flame retardant is preferable. Also, from the same viewpoint, in the classification focusing on the action mechanism of the flame retardant, the flame retardant is preferably an intumescent flame retardant.

[0021] A phosphorus-based flame retardant is a phosphorus compound, that is, a compound containing a phosphorus atom in its molecule. The phosphorus-based flame retardant exerts a flame retardant effect by forming a char during combustion. The phosphorus-based flame retardant may be a known one, and examples thereof include (poly)phosphate, (poly)phosphoric acid ester, etc. "(Poly)phosphate" indicates phosphate or polyphosphate. "(Poly)phosphoric acid ester" indicates phosphoric acid ester or polyphosphoric acid ester. The phosphorus-based flame retardant is preferably solid at 80°C.

[0022] As the phosphorus-based flame retardant, (poly)phosphate is preferable in terms of flame retardancy. (Poly)phosphates include, for example, ammonium polyphosphate, melamine polyphosphate, piperazine polyphosphate, piperazine orthophosphate, melamine pyrophosphate, piperazine pyrophosphate, melamine orthophosphate, calcium phosphate, and magnesium phosphate. In addition, in the above examples, compounds in which melamine or piperazine is replaced with another nitrogen compound can be used in the same manner. Examples of other nitrogen compounds include N,N,N’,N’-tetramethyldiaminomethane, ethylenediamine, N,N’-dimethylethylenediamine, N,N’-diethylethylenediamine, N,N-dimethylethylenediamine, N,N-diethylethylenediamine, N,N,N’,N’-tetramethylethylenediamine, N,N,N’,N’-diethylethylenediamine, 1,2-propanediamine, 1,3-propanediamine, tetramethylenediamine, pentamethylenediamine, hexamethylenediamine, 1,7-diaminoheptane, 1,8-diaminooctane, 1,9-diaminononane, 1,10-diaminodecane, trans-2,5-dimethylpiperazine, 1,4-bis(2-aminoethyl)piperazine, 1,4-bis(3-aminopropyl)piperazine, acetoguanamine, benzoguanamine, acrylguanamine, 2,4-diamino-6-nonyl-1,3,5-triazine, 2,4-diamino-6-hydroxy-1,3,5-triazine, 2-amino-4,6-dihydroxy-1,3,5-triazine, 2,4-diamino-6-methoxy-1,3,5-triazine, 2,4-diamino-6-ethoxy-1,3,5-triazine, 2,4-diamino-6-propoxy-1,3,5-triazine, 2,4-diamino-6-isopropoxy-1,3,5-triazine, 2,4-diamino-6-mercapto-1,3,5-triazine, 2-amino-4,6-dimercapto-1,3,5-triazine, ammelin, benzoguanamine, acetoguanamine, phthalodiguanamine, melamine cyanurate, butylenediguanamine, norbornenediguanamine, methylenediguanamine, ethylenedimelamine, trimethylenedimelamine, tetramethylenedimelamine, hexamethylenedimelamine, 1,3-hexylenedimelamine, and the like. These (poly)phosphates may be used alone or in combination of two or more.

[0023] Among the phosphorus-based flame retardants, salts of (poly)phosphoric acid and nitrogen compounds are preferred. Salts of (poly)phosphoric acid and nitrogen compounds are intumescent flame retardants, which form a surface expansion layer (intumescent) of foamed char during combustion. By forming the surface expansion layer, the diffusion of decomposition products and heat transfer are suppressed, and excellent flame retardancy is exhibited. Examples of the nitrogen compound in the salt of (poly)phosphoric acid and nitrogen compound include ammonia, melamine, piperazine, and the other nitrogen compounds described above. In addition, examples of intumescent flame retardants include ammonium salts and amine salts of (poly)phosphoric acid such as ammonium polyphosphate, melamine polyphosphate, piperazine polyphosphate, ammonium pyrophosphate, melamine pyrophosphate, and piperazine pyrophosphate.

[0024] Examples of commercially available phosphorus-based flame retardants include Adekastab FP-2100J, FP-2200, and FP-2500S (manufactured by ADEKA).

[0025] When the board contains a flame retardant, the content of the flame retardant in the board is not particularly limited, but is preferably 1 to 30% by mass. When the content of the flame retardant is 1% by mass or more, good flame shielding properties can be obtained, and when it is 30% by mass or less, other components (synthetic resin, dispersant and fiber described later, etc.) can be contained in a sufficient amount, and for example, good molding processability can be obtained. From the above viewpoints, the content of the flame retardant is more preferably 1 to 25% by mass, and even more preferably 3 to 20% by mass.

[0026] The board may contain a dispersant in order to enhance the dispersibility of the flame retardant in the synthetic resin. The dispersant is not particularly limited as long as it can disperse the flame retardant in the synthetic resin. However, when using a thermoplastic resin suitable as the synthetic resin, a polymer dispersant can be preferably used in terms of compatibility with the thermoplastic resin. As the polymer dispersant, a polymer dispersant having a carboxyl group is preferable. When using a phosphorus-based flame retardant suitable as the flame retardant, a copolymer of an α-olefin and an unsaturated carboxylic acid (hereinafter, also referred to as "copolymer") is preferable. By using this dispersant, the dispersibility of the phosphorus-based flame retardant can be improved, and the content of the flame retardant can be reduced.

[0027] The copolymer of an α-olefin and an unsaturated carboxylic acid means a copolymer in which the proportion of α-olefin units is 20 mol% or more and 80 mol% or less out of a total of 100 mol% of α-olefin units and unsaturated carboxylic acid units. In the copolymer, the proportion of α-olefin units relative to the total mass of α-olefin units and unsaturated carboxylic acid units is preferably 30 mol% or more, and on the other hand, preferably 70 mol% or less. If the proportion of the α-olefin is at least the lower limit value, the compatibility with a polyolefin-based resin, which is particularly suitable as the synthetic resin, is more excellent. If it is at most the upper limit value, the compatibility with a phosphorus-based flame retardant, which is suitable as the flame retardant, is more excellent.

[0028] In the copolymer, as the α-olefin, an α-olefin having 5 or more carbon atoms is preferable, and an α-olefin having 10 or more and 80 or less carbon atoms is more preferable. If the number of carbon atoms of the α-olefin is 5 or more, the compatibility with a thermoplastic resin suitable as the synthetic resin tends to be better. If it is 80 or less, it is advantageous in terms of raw material cost. The number of carbon atoms of the α-olefin is more preferably 12 or more and 70 or less, and particularly preferably 18 or more and 60 or less.

[0029] In the copolymer, examples of the unsaturated carboxylic acid include (meth)acrylic acid, maleic acid, methylmaleic acid, fumaric acid, methylfumaric acid, tetrahydrophthalic acid, itaconic acid, citraconic acid, crotonic acid, isocrotonic acid, glutaconic acid, norbornene-5-ene-2,3-dicarboxylic acid, and esters, anhydrides, imides, etc. of these unsaturated carboxylic acids. “(Meth)acrylic acid” means acrylic acid or methacrylic acid. Specific examples of the ester, anhydride or imide of the unsaturated carboxylic acid include (meth)acrylic acid esters such as methyl (meth)acrylate, ethyl (meth)acrylate, butyl (meth)acrylate, 2-ethylhexyl (meth)acrylate, glycidyl (meth)acrylate; dicarboxylic acid anhydrides such as maleic anhydride, itaconic anhydride, citraconic anhydride, 5-norbornene-2,3-dicarboxylic anhydride; maleimide compounds such as maleimide, N-ethylmaleimide, N-phenylmaleimide, etc. These may be used alone or in combination of two or more. Among the above, esters and dicarboxylic acid anhydrides are preferred from the viewpoint of copolymerization reactivity. Among them, dicarboxylic acid anhydrides are preferred, and maleic anhydride is particularly preferred, from the viewpoint of compatibility with phosphorus-based flame retardants suitable as flame retardants.

[0030] The weight average molecular weight of the copolymer is preferably 2,000 or more, more preferably 3,000 or more. On the other hand, it is preferably 50,000 or less, more preferably 30,000 or less. When the weight average molecular weight of the copolymer is within the above upper and lower limit ranges, the dispersibility of the flame retardant is more excellent. The weight average molecular weight of the copolymer is a value in terms of standard polystyrene measured by gel permeation chromatography after dissolving the copolymer in tetrahydrofuran (THF).

[0031] Commercially available products of the copolymer include Licolube CE2 (manufactured by Clariant Japan Co., Ltd.) and Diacarna 30M (manufactured by Mitsubishi Chemical Corporation).

[0032] When the board contains a flame retardant and a dispersant, the content of the dispersant with respect to 100 parts by mass of the flame retardant in the board is more than 0 and in the range of 25 parts by mass or less, preferably in the range of 0.01 to 10 parts by mass.

[0033] The board containing a synthetic resin may be formed from a resin fiber composite material (fiber reinforced material) in which fibers are mixed with the synthetic resin. For example, a resin composition containing fibers such as glass fibers and carbon fibers in the synthetic resin may be used, or the synthetic resin may be impregnated with fibers such as glass fibers and carbon fibers. Further, the board containing a synthetic resin may have a flat shape, or may be shaped into a three-dimensional shape in part or in whole by hot pressing or the like. Preferably, the fibers contain inorganic fibers. As the inorganic fibers, various fibers can be used, for example, metal oxide fibers such as glass fibers, rock wool, alumina fibers, and silica alumina fibers, ceramic fibers such as potassium titanate fibers, calcium silicate (wollastonite) fibers, and ceramic fibers, carbon fibers, metal fibers, and the like. These inorganic fibers may be used alone or in combination of two or more. Among the inorganic fibers, from the viewpoints of flame shielding property and processability, it is preferable to contain glass fibers. That is, it is preferable that the fibers contain glass fibers.

[0034] When the board contains fibers, the content of the fibers in the board is not particularly limited, but is preferably 1 to 80% by mass. When the fiber content is 1% by mass or more, a decrease in strength, rigidity, and impact resistance can be suppressed, and when it is 80% by mass or less, manufacturing and processing are easy, and a weight reduction effect as a metal substitute can also be obtained. From the above viewpoints, the fiber content is more preferably 3 to 60% by mass, still more preferably 10 to 50% by mass, and particularly preferably 30 to 45% by mass.

[0035] As the resin fiber composite material, a stampable sheet is preferable, and a stampable sheet produced by impregnating a mat made of fibers with a synthetic resin is more preferable. When the board contains a flame retardant and a dispersant, it is preferable to manufacture a stampable sheet by impregnating a mat made of fibers with a resin composition containing a synthetic resin, a flame retardant, a dispersant, optional additives, etc., excluding the fibers. As a method for manufacturing the resin composition, a conventionally known method can be used, and it can be manufactured by blending the above components and mixing and melt-kneading them. Mixing is performed using a mixer such as a tumbler, a V blender, or a ribbon blender, and melt-kneading is performed using equipment such as a single-screw extruder, a twin-screw extruder, a Banbury mixer, a roll mixer, a Brabender plastograph, or a kneader, and is melt-kneaded and granulated. Also, as a method of impregnation, there are a method of applying a synthetic resin or a resin composition to a mat made of fibers, a method of preparing a sheet of a synthetic resin or a resin composition, laminating the sheet on a mat made of fibers, and heating and melting to impregnate, etc. From the viewpoint of surface smoothness, the latter method is preferable. More specifically, the method described in International Publication No. 2022 / 220303 can be used.

[0036] When the board containing a synthetic resin has a three-dimensional shape, for example, the stampable sheet may be made into a case shape, and various methods can be used. From the viewpoint of productivity, press molding is preferable. In press molding, for example, it is preferable to prepare a stampable sheet, stack a plurality of sheets, and perform press molding.

[0037] <Thermoplastic elastomer layer> This laminate includes a thermoplastic elastomer layer. As a material for forming the thermoplastic elastomer layer, it may be rubber alone or a composition containing rubber and a thermoplastic resin, and it is preferably a composition containing rubber and a thermoplastic resin. Among them, from the viewpoint of recycling, it is preferably a material containing either or both of an olefin-based rubber or a polyolefin-based resin. The thermoplastic elastomer layer is formed of an elastomer containing either or both of an olefin rubber or a polyolefin resin excellent in recyclability, so that it can be melted and reformed by reheating after use and can be material-recycled as a new product such as a recycled molded product.

[0038] The olefin rubber is preferably a copolymer containing at least two or more α-olefin units. Examples of the α-olefin include ethylene, propylene, 1-butene, 2-methylpropylene, 1-pentene, 3-methyl-1-butene, 1-hexene, 4-methyl-1-pentene, 1-octene and the like. From the viewpoint of material recycling, it is preferable to contain ethylene having 2 carbon atoms and propylene having 3 carbon atoms. The α-olefin may be a copolymer of only one kind with ethylene or a copolymer of two or more kinds with ethylene. Also, the olefin rubber may be used alone or in combination of two or more kinds.

[0039] In addition to the ethylene unit and the α-olefin unit having 3 to 8 carbon atoms, the olefin rubber may have other monomer units such as monomer units (non-conjugated diene units) based on non-conjugated dienes. Examples of the non-conjugated diene include chain non-conjugated dienes such as 1,4-hexadiene, 1,6-octadiene, 2-methyl-1,5-hexadiene, 6-methyl-1,5-heptadiene, 7-methyl-1,6-octadiene; cyclic non-conjugated dienes such as cyclohexadiene, dicyclopentadiene, methyltetrahydroindene, 5-vinylnorbornene, 5-ethylidene-2-norbornene, 5-methylene-2-norbornene, 5-isopropylidene-2-norbornene, 6-chloromethyl-5-isopropenyl-2-norbornene. Preferably, they are 5-ethylidene-2-norbornene and dicyclopentadiene. Further, the ethylene-propylene copolymer, ethylene-propylene-diene copolymer, and ethylene-butene copolymer may be partially or completely crosslinked. Among them, from the viewpoints of moldability and rubber elasticity, it is preferably partially crosslinked.

[0040] As a method for producing an olefin rubber, a known polymerization method using a known catalyst for olefin polymerization is used. For example, as the catalyst for olefin polymerization, a Ziegler-Natta catalyst, a complex catalyst such as a metallocene complex or a non-metallocene complex can be used, and examples of the polymerization method include a slurry polymerization method, a solution polymerization method, a bulk polymerization method, and a gas phase polymerization method. It is also possible to use commercially available corresponding products. Examples of commercially available corresponding products include the Engage (registered trademark) series manufactured by Dow Chemical Company and the Tafmer (registered trademark) series manufactured by Mitsui Chemicals, Inc.

[0041] As the polyolefin resin, crystalline polyolefin is preferable from the viewpoints of light weight, stable rubber elasticity, excellent mechanical properties, and good moldability. The above crystalline polyolefin may be an unmodified crystalline polyolefin, or may be a modified crystalline polyolefin modified with at least one functional group selected from the group consisting of an acid anhydride group, a carboxyl group, an amino group, an imino group, an alkoxysilyl group, a silanol group, a silyl ether group, a hydroxyl group, and an epoxy group.

[0042] Examples of the crystalline polyolefin include propylene polymers, ethylene polymers, etc. These may be used alone or in combination of two or more.

[0043] Examples of the propylene polymer include a propylene homopolymer, and a propylene copolymer which is a random or block copolymer of polypropylene and an α-olefin such as ethylene or 1-butene, 1-hexene. The melt flow rate (JIS K 7210, 230°C, 21.2 N load) of the propylene-based polymer is not particularly limited, but is usually 0.05 to 200 g / 10 min, preferably 0.05 to 100 g / 10 min, and more preferably 0.1 to 80 g / 10 min. By setting the melt flow rate within the above range, the moldability is excellent, the appearance of the resulting thermoplastic elastomer layer is good, and the mechanical properties can be controlled within a desired range.

[0044] Commercially available products of the propylene-based polymer can also be used. Commercially available polypropylenes can be procured from the manufacturers listed below and can be appropriately selected. Commercially available products that can be obtained include Novatec (registered trademark) PP of Japan Polypropylene Co., Ltd., Prime Polypro (registered trademark) of Prime Polymer Co., Ltd., Sumitomo Nolen (registered trademark) of Sumitomo Chemical Co., Ltd., polypropylene block copolymer of Sun Allomer Co., Ltd., Moplen (registered trademark), Circluen of LyondellBasell Co., Ltd., ExxonMobil PP of ExxonMobil Co., Ltd., Formolene (registered trademark) of Formosa Plastics Co., Ltd., Borealis PP of Borealis Co., Ltd., SEETEC PP of LG Chemical Co., Ltd., ASI POLYPROPYLENE of A. Schulman Co., Ltd., INEOS PP of INEOS Olefins & Polymers Co., Ltd., Braskem PP of Braskem Co., Ltd., Sumsung Total of SAMSUNG TOTAL PETROCHEMICALS Co., Ltd., Sabic (registered trademark) PP of Sabic Co., Ltd., TOTAL PETROCHEMICALS Polypropylene of TOTAL PETROCHEMICALS Co., Ltd., YUPLENE (registered trademark) of SK Co., Ltd., etc.

[0045] Examples of the ethylene-based polymer include high-density polyethylene, low-density polyethylene, and linear low-density polyethylene. The density of the ethylene-based polymer measured by JIS K 7112 is 0.910 g / cm 3 or more and 1.00 g / cm 3The following are preferred from the viewpoint of compatibility between mechanical properties and rubber elasticity. The melt flow rate (JIS K 7210, 190 °C, 21.2 N load) of the ethylene polymer is not particularly limited, but is usually 0.05 to 200 g / 10 min, preferably 0.05 to 100 g / 10 min, and more preferably 0.1 to 80 g / 10 min. By setting the melt flow rate within the above range, the moldability is excellent, the appearance of the obtained thermoplastic elastomer layer is good, and the mechanical properties can be controlled within a desired range.

[0046] The molecular weights of the above-mentioned propylene polymer and ethylene polymer are not particularly limited, but it is preferable to contain a resin having a weight average molecular weight of 500 to 1,500,000 measured by gel permeation chromatography (GPC). This weight average molecular weight is more preferably 1,000 to 1,000,000, and even more preferably 2,000 to 500,000. The above weight average molecular weight is measured using standard polystyrene as a molecular weight standard substance.

[0047] As described above, the thermoplastic elastomer layer is preferably formed from a material containing either or both of an olefin rubber and a polyolefin resin, more preferably formed from a material containing at least a polyolefin resin, and even more preferably a composition containing an olefin rubber and a polyolefin resin or a composition containing a rubber component other than an olefin rubber and a polyolefin resin. When the thermoplastic elastomer layer is formed from a composition containing a rubber component other than an olefin rubber and a polyolefin resin, it is preferably a composition containing a polyolefin resin and a styrene copolymer rubber as a rubber component other than an olefin rubber.

[0048] The composition containing a rubber and a thermoplastic resin may contain a hydrocarbon-based softening agent for rubber from the viewpoints of improving the processability and fluidity of the composition. Examples of hydrocarbon-based softeners for rubber include mineral oil-based softeners and synthetic resin-based softeners, with mineral oil-based softeners being particularly preferred. Mineral oil-based softeners are generally mixtures of aromatic hydrocarbons, naphthenic hydrocarbons, and paraffinic hydrocarbons. Those with more than 50% of all carbon atoms being paraffinic hydrocarbons are called paraffinic oils, those with 30 - 45% of all carbon atoms being naphthenic hydrocarbons are called naphthenic oils, and those with 35% or more of all carbon atoms being aromatic hydrocarbons are called aromatic oils. Among these, paraffinic oils are preferred.

[0049] The kinematic viscosity at 40°C of the hydrocarbon-based softener for rubber is preferably 20 centistokes (cSt) or more, more preferably 50 cSt or more. On the other hand, it is preferably 800 cSt or less, more preferably 600 cSt or less. Also, the flash point (COC method) of the hydrocarbon-based softener for rubber is preferably 200°C or more, more preferably 250°C or more.

[0050] Commercially available hydrocarbon-based softeners for rubber may be used. Examples of commercially available products include the "ENEOS POLYBUTENE (registered trademark) HV" series manufactured by ENEOS, the "DIANA (registered trademark) PROCESS OIL PW" series manufactured by Idemitsu Kosan Co., Ltd., and the "VIVA - B - FIX" (registered trademark) series manufactured by H&R.

[0051] The hydrocarbon-based softener for rubber can be used alone as only one type, or in any combination and ratio of two or more types.

[0052] As a composition containing an olefin rubber and a polyolefin resin, commercially available products can also be used. For example, Milastomer (registered trademark) manufactured by Mitsui Chemicals, Inc., Espolex TPE series (registered trademark) manufactured by Sumitomo Chemical Co., Ltd., Thermoran (registered trademark) manufactured by Mitsubishi Chemical Corporation, Trexplane (registered trademark) manufactured by Mitsubishi Chemical Corporation, Tefabloc (registered trademark) TPO manufactured by Mitsubishi Chemical Corporation, Santoprene (registered trademark) manufactured by Celanese, Sarlink (registered trademark) manufactured by Toyobo MSC Co., Ltd., Dawnprene (registered trademark) manufactured by Shandong Dawn Polymer, etc. can be mentioned.

[0053] As a composition containing a styrene copolymer rubber and a polyolefin resin, commercially available products can also be used. For example, Tefabloc (registered trademark) TPS manufactured by Mitsubishi Chemical Corporation, Leostomer (registered trademark) manufactured by Riken Technos Corporation, Elastomer AR (registered trademark) manufactured by Aron Kasei Co., Ltd., Arastommer (registered trademark) manufactured by Aron Kasei Co., Ltd., Erneston (registered trademark) manufactured by Kuraray Plastics Co., Ltd., THERMOLAST (registered trademark) manufactured by KRAIBURG TPE GMBH & CO.KG, etc. can be mentioned.

[0054] The thermoplastic elastomer layer may be imparted with flame retardancy in order to suppress fracture during thermal runaway. For example, as a material for forming the thermoplastic elastomer layer, a composition containing rubber alone and / or a composition containing rubber and a thermoplastic resin, and a flame retardant may be used. As the flame retardant, those exemplified as flame retardants that may be contained in a plate containing a synthetic resin can be preferably used. In addition, a dispersant may be contained in order to enhance the dispersibility of the flame retardant in the rubber alone or the composition containing rubber and a thermoplastic resin in the material for forming the thermoplastic elastomer layer. As the dispersant, those exemplified as dispersants that may be contained in a plate containing a synthetic resin can be preferably used. When the material for forming the thermoplastic elastomer layer contains a flame retardant and a dispersant, the proportion of the rubber alone and / or the composition containing rubber and a thermoplastic resin with respect to the total mass of the material for forming the thermoplastic elastomer layer is preferably 20% by mass or more, more preferably 30% by mass or more, still more preferably 40% by mass or more, even more preferably 45% by mass or more, particularly preferably 50% by mass or more. On the other hand, it is preferably 80% by mass or less, more preferably 70% by mass or less, still more preferably less than 60% by mass. If the proportion of the rubber alone and / or the composition containing rubber and a thermoplastic resin is at least the above lower limit value, the original physical properties of the rubber alone and / or the composition containing rubber and a thermoplastic resin are likely to be exhibited. If it is at most the above upper limit value, the flame retardancy is more excellent. The proportion of the flame retardant with respect to the total mass of the material for forming the thermoplastic elastomer layer is preferably 35% by mass or more, more preferably 38% by mass or more, still more preferably 40% by mass or more. On the other hand, it is preferably 50% by mass or less, more preferably 48% by mass or less, still more preferably 45% by mass or less. If the proportion of the flame retardant is at least the above lower limit value, the flame retardancy is more excellent. If it is at most the above upper limit value, the original physical properties (for example, high mechanical properties and flexibility) of the composition containing the rubber alone and / or the rubber and the thermoplastic resin are likely to be exhibited. The proportion of the dispersant with respect to the total mass of the material for forming the thermoplastic elastomer layer is preferably 0.01% by mass or more, more preferably 0.03% by mass or more, still more preferably 0.1% by mass or more, even more preferably 0.5% by mass or more, particularly preferably 1% by mass or more. On the other hand, it is preferably 10% by mass or less, more preferably 5% by mass or less, still more preferably 3% by mass or less. If the proportion of the dispersant is at least the above lower limit value, the flame retardant is well dispersed, and the flame retardancy, high flexibility, mechanical properties of the material for forming the thermoplastic elastomer layer, and the appearance of the obtained thermoplastic elastomer layer are good. If the proportion of the dispersant is at most the above upper limit value, the influence of the dispersant on the flame retardancy of the material for forming the thermoplastic elastomer layer can be suppressed.

[0055] In addition, the thermoplastic elastomer layer may be imparted with conductivity in order to shield electromagnetic waves. For example, a composition containing rubber alone and / or a composition containing rubber and a thermoplastic resin and a conductive agent as a material for forming the thermoplastic elastomer layer may be used, or a two-color molding of a composition containing a material for forming the thermoplastic elastomer layer and a conductive agent may be performed. As the conductive agent, conventionally known ones can be used.

[0056] Any method can be adopted to manufacture the material for forming the thermoplastic elastomer layer. For example, a method of sufficiently mixing using preliminary mixing means such as a V-type blender, a Henschel mixer, a mechanochemical device, an extrusion mixer, etc., granulating by an extrusion granulator or a briquetting machine as the case may be, and then melt-kneading and extruding with a melt-kneading machine can be mentioned. Examples of the melt-kneading machine include a twin-screw extruder such as a vented twin-screw extruder, a Banbury mixer, a kneading roll, a single-screw extruder, a multi-screw extruder with three or more axes, etc. The temperature during melt-kneading is, for example, 170 to 260°C. The material for forming the thermoplastic elastomer layer extruded as described above is directly cut by a device such as a pelletizer to be pelletized, or after being cooled to form a strand, such a strand is cut by a device such as a pelletizer to be pelletized.

[0057] The thermoplastic elastomer layer can be obtained by molding the material for forming the thermoplastic elastomer layer. Examples of the molding method include extrusion processing, calendering, injection molding, rolling, compression molding, press molding, blow molding, three-dimensional laminated modeling, etc., and it is preferably molded by a three-dimensional laminated modeling method. The three-dimensional lamination molding method is molding by a 3D printer. As the 3D printer, it is preferable to use a printer of the material extrusion method (MEX method). The material for forming the thermoplastic elastomer layer can be supplied to the 3D printer in the form of pellets, powders, granules, filaments, etc., and it is desirable to perform molding using a type of 3D printer that can use pellet or granular molding materials. Examples of such printers include those that control the drive of the extrusion nozzle in a gantry method and those that use a robotic arm method. The temperature at the time of molding the material for forming the thermoplastic elastomer layer is, for example, 170 to 260°C.

[0058] In this laminate, the thermoplastic elastomer layer is in direct contact with the plate. Examples of the manufacturing method of such a laminate include a method of integrating the thermoplastic elastomer layer alone by three-dimensional lamination molding or the like and then integrating it with the plate, and a method of directly molding on the plate. As will be described later, it is preferable to directly mold on the plate. By taking such a method, there is an advantage that an adhesive layer does not need to be provided, and a laminate having high adhesive strength and excellent sealing properties is obtained. Among them, it is preferable that the thermoplastic elastomer layer is heat-sealed to a plate containing a synthetic resin. By taking such a method, it is also possible to integrally mold the plate and the thermoplastic elastomer layer to obtain a laminate. Examples of this integral molding technique include integration of the thermoplastic elastomer layer and the plate by hot press molding, and molding of the thermoplastic elastomer layer on the plate by the above-described three-dimensional lamination molding method. From the viewpoint of manufacturing efficiency, it is more preferable to directly mold the thermoplastic elastomer layer on the plate by the three-dimensional lamination molding method. At this time, for the purpose of improving the heat-sealing property, the plate may be heated before or during molding by a 3D printer. This heating temperature is, for example, 40 to 160°C.

[0059] Particularly preferred embodiments of the present invention include forming from a plate containing a polyolefin resin as a synthetic resin and forming the thermoplastic elastomer layer from a material containing either or both of an olefin rubber or a polyolefin resin. That is, by forming the thermoplastic elastomer layer and the plate from the same polyolefin-based material, it becomes possible to perform material recycling of the thermoplastic elastomer layer and the plate together after use. Another preferred embodiment is to form the thermoplastic elastomer layer from a material containing an acid-modified polyolefin-based thermoplastic elastomer and form the plate from a plate containing a polyamide resin as a synthetic resin.

[0060] In this laminate, the thermoplastic elastomer layer occupies an area of 90% or less with respect to the surface area of the plate. By adhering the thermoplastic elastomer layer so that it occupies an area of 90% or less with respect to the surface area of the plate, it becomes possible to use the minimum amount of material necessary for the manifestation of the sealing effect, resulting in effects such as weight reduction and cost reduction. On the other hand, by adhering it so that it preferably occupies an area of 0.1% or more with respect to the surface area of the plate, sufficient sealing performance can be exhibited. From such a viewpoint, the thermoplastic elastomer layer preferably occupies an area of 80% or less with respect to the surface area of the plate, more preferably 70% or less, still more preferably 0.3% or more, and even more preferably 0.5% or more.

[0061] From the viewpoints of weight reduction and cost reduction, the thickness of the thermoplastic elastomer layer is preferably 10 mm or less, more preferably 8 mm or less, and even more preferably 6 mm or less. On the other hand, from the viewpoint of exhibiting sufficient sealing performance, the thickness of the thermoplastic elastomer layer is preferably 1 mm or more, more preferably 1.5 mm or more. Also, the difference between the maximum thickness and the minimum thickness of the thermoplastic elastomer layer is 1.5 mm or less. If the difference between the maximum thickness and the minimum thickness is 1.5 mm or less, since the thickness error is small, the thermoplastic elastomer layer is not uneven, and the thermoplastic elastomer layer does not float from the plate, and the sealing property is excellent. Also, when adhering another material to the surface of the thermoplastic elastomer layer opposite to the plate, the thermoplastic elastomer layer is not uneven, and the sealing property is excellent. The smaller the difference between the maximum thickness and the minimum thickness, the better, and the lower limit value is 0. From this perspective, the difference between the maximum thickness and the minimum thickness is preferably 1.3 mm or less, more preferably 1.0 mm or less. As a method for reducing the difference, when molding by a 3D printer, optimization of the shaping shape, shaping path, discharge amount, discharge width, etc. can be mentioned. For example, when the shaping path is a shape that bends at a right angle or an acute angle, resin stays at the bending portion, and unevenness of the material (elastomer) forming the thermoplastic elastomer layer is likely to occur. Also, when the paths overlap at the start point and the end point of the shaping path, unevenness is likely to occur at the overlapping portion, so it is preferable to adjust the discharge amount, discharge width, etc. At this time, it is preferable to adjust the discharge amount, discharge width, etc. within a range where the size of the unevenness does not affect the sealing property so that no gap occurs between the paths at the overlapping portion of the paths. Here, the maximum thickness and the minimum thickness of the thermoplastic elastomer layer refer to the maximum thickness and the minimum thickness of the thermoplastic elastomer layer installed in a frame shape so as to surround the periphery of the housing portion in the battery pack described later. At this time, the thermoplastic elastomer layer may be formed in one layer by lamination with a 3D printer, or may be formed in two or more layers.

[0062] <<Battery Pack>> The battery pack according to the present invention (hereinafter, also referred to as "this battery pack") uses this laminate. The laminate in this battery pack corresponds to the thermoplastic elastomer layer 61 and the upper case 22, and / or the thermoplastic elastomer layer 61 and the lower case 42, which will be described later. That is, the thermoplastic elastomer layer in this structure corresponds to the thermoplastic elastomer layer 61, and the plate containing the synthetic resin corresponds to the upper case 22 and / or the lower case 42. Further, the laminated portion of the thermoplastic elastomer layer and the plate corresponds to the thermoplastic elastomer layer 61 and the upper flange 24, and / or the thermoplastic elastomer layer 61 and the lower flange 44.

[0063] Hereinafter, an electric vehicle using an embodiment of the battery pack according to the present invention will be described with reference to FIG. 1. As shown in FIG. 1, this electric vehicle 1 includes a chassis 10, tires 15, and the battery pack 20 of this embodiment. For example, the chassis 10 of this embodiment constitutes a part of the skeleton of the electric vehicle 1. The chassis 10 extends along a horizontal plane. Here, when it is said that A is along B, it means that the angle formed by A and B is 30 degrees or less. It is more preferable that this formed angle is 15 degrees or less. For example, A corresponds to the chassis 10 and B corresponds to the horizontal plane. The chassis 10 supports a motor (not shown). An opening 10a penetrating in the vertical direction is formed in the chassis 10. A plurality of through holes (reference signs omitted) penetrating in the vertical direction are formed in the peripheral portion of the opening 10a in the chassis 10.

[0064] The battery pack 20 is supported by the chassis 10. Electric power is stored in the battery pack 20. The battery pack 20 supplies the stored electric power to the motor based on an instruction from the operator of the electric vehicle 1. Details of the battery pack 20 will be described later. The tires 15 are rotatably supported by the chassis 10 via a suspension (not shown). The motor rotates the tires 15 in a predetermined direction.

[0065] As shown in FIG. 1, the battery pack 20 includes a case 21, a power storage unit 51, and a fixing unit 56. The case 21 has an upper case 22 and a lower case 42. The upper case 22 has an upper case body 23 and an upper flange 24. The upper case body 23 is formed in a toped cylindrical shape. That is, the upper case body 23 has an upper side wall 32 and a top wall 33. Therefore, the power storage unit 51 can be accommodated in a part of the accommodation space S1 formed in the upper side wall 32. The upper side wall 32 is formed in a rectangular edge-shaped square tube shape (tube shape) when viewed in the vertical direction. Hereinafter, the direction along one outer edge (short side) of the upper side wall 32 when viewed in the vertical direction is referred to as the first direction X. The first direction X is a direction along the horizontal plane. Hereinafter, the direction orthogonal to the vertical direction and orthogonal to the first direction X is referred to as the second direction Y.

[0066] Note that the shape of the upper side wall 32 is not limited to this, and may be formed in a tube shape presenting a triangular, pentagonal or more edge shape, a circular edge shape, etc. when viewed in the vertical direction. The top wall 33 closes the opening formed at the upper end of the upper side wall 32. Hereinafter, the central axis of the top wall 33 is referred to as the axis O1. For example, the axis O1 is an axis passing through the center of gravity of the top wall 33 and along the vertical direction.

[0067] The upper flange 24 protrudes from the outer peripheral edge of the lower end of the upper side wall 32 in the upper case body 23 along the horizontal plane toward the outside of the upper side wall 32. The outside mentioned here means the direction away from the axis O1. The upper flange 24 protrudes over the entire circumference of the upper side wall 32. Note that the upper flange 24 may protrude only a part of the circumferential direction of the upper side wall 32 (a part around the axis O1). A plurality of through holes (reference numerals omitted) penetrating in the vertical direction are formed in the upper flange 24. The plurality of through holes are arranged at intervals around the upper side wall 32.

[0068] The upper case body 23 and the upper flange 24 of the upper case 22 are integrally formed of a resin material.

[0069] As shown in FIG. 1, the lower case 42 has a lower case body 43 and a lower flange 44. The lower case body 43 is formed in a bottomed cylindrical shape. That is, the lower case body 43 has a lower side wall 47 and a bottom wall 48. Similar to the upper side wall 32, the lower side wall 47 is formed in a square tube shape presenting a rectangular edge when viewed in the vertical direction. The bottom wall 48 closes an opening formed at the lower end of the lower side wall 47.

[0070] The lower flange 44 protrudes outward along a horizontal plane from the outer peripheral edge of the lower side wall 47 of the lower case body 43. The lower flange 44 is arranged to face the upper flange 24 from below the upper flange 24. Here, when it is said that A faces B, it means that A and B face each other with a space therebetween. A plurality of through holes (reference numerals omitted) penetrating in the vertical direction are formed in the lower flange 44. The plurality of through holes are arranged at intervals around the lower side wall 47.

[0071] The lower case 42 (including the lower case body 43 and the lower flange 44) may be integrally formed of the same material as the resin material forming the upper case 22, or may be formed of iron, aluminum, or the like.

[0072] The thermoplastic elastomer layer 61 is formed of a material forming the thermoplastic elastomer layer and is formed between the upper flange 24 and the lower flange 44. That is, the thermoplastic elastomer layer 61 is provided between the upper flange 24 and the lower flange 44. An adhesive layer or the like may be provided between the thermoplastic elastomer layer 61 and the upper flange 24, or between the thermoplastic elastomer layer 61 and the lower flange 44. However, from the viewpoints of waterproof and dustproof properties and suppression of an increase in the number of parts, the thermoplastic elastomer layer 61 is in direct contact with at least one of the upper flange 24 and the lower flange 44. Note that the thermoplastic elastomer layer 61 may be in contact with the through hole or may be installed at a position away from the through hole. Further, the thermoplastic elastomer layer 61 may be installed only on the power storage unit side from the through hole. In addition, since the thermoplastic elastomer layer functions as a sealing material for waterproof and dustproof purposes, it is installed in a frame shape so as to surround the periphery of the housing portion so that water and dust do not enter the housing space S1. For example, as shown in FIG. 2, it is installed on the lower flange. Although not shown, it can be similarly installed on the upper flange. At this time, the maximum thickness and the minimum thickness of the thermoplastic elastomer layer described above refer to the maximum thickness and the minimum thickness of the thermoplastic elastomer layer installed in a frame shape so as to surround the periphery of the housing portion. For example, in a shaped portion that protrudes outward or inward from the periphery of the housing portion as in part A of FIG. 2, it is considered that even if the thickness becomes extremely thin, the sealing performance is not affected. The "maximum thickness and minimum thickness of the thermoplastic elastomer layer" in the present patent does not target the thickness of a portion having a shape that protrudes outward or inward from the peripheral portion of the housing portion such as this portion A.

[0073] The power storage unit 51 is a known secondary battery. The power storage unit 51 stores a predetermined amount of electric power and supplies this electric power to the outside. For example, the power storage unit 51 is a lithium ion battery. The power storage unit 51 is disposed in a housing space S1 formed by the upper case body 23 and the lower case body 43. By arranging the upper flange 24 and the lower flange 44 to face each other, the power storage unit 51 is held in a housing space S1 formed between the upper case body 23 and the lower case body 43.

[0074] For example, the fixing portion 56 includes a plurality of bolts 57 and a plurality of nuts 58. The head of the bolt 57 is in contact with the upper flange 24 of the upper case 22 from above the upper flange 24. The shaft portion of the bolt 57 is passed through the through-hole of the upper case 22, the through-hole of the lower case 42, and the through-hole of the chassis 10, respectively. The nut 58 is in contact with the lower flange 44 of the lower case 42 from below the lower flange 44. The nut 58 is fitted onto the shaft portion of the bolt 57. The head of the bolt 57 and the nut 58 sandwich the upper flange 24, the lower flange 44, and the chassis 10 in the vertical direction.

[0075] The battery pack 20 can be variously deformed in its configuration as described below. In the battery pack of the first modification example, in each configuration of the battery pack 20 of the present embodiment, the upper case body 23 and the upper flange 24 of the upper case 22 are formed of iron, aluminum, etc. instead of the resin material, and the lower case body 43 and the lower flange 44 of the lower case 42 are formed of a resin material instead of iron, aluminum, etc.

Example

[0076] Hereinafter, the present invention will be specifically described by way of examples. However, the present invention is not limited by the following examples in any way. In the following examples, etc., % is based on mass unless otherwise specified. The evaluation was carried out for the following items.

[0077] 1. Measurement of adhesive strength A plate containing a synthetic resin was cut into 10 cm × 20 cm, and after covering the surface with a polyimide (PI) sheet, only a part was removed so as to form a strip having a width of 1.25 cm in the longitudinal direction to expose the plate surface. On this plate, a material for forming a thermoplastic elastomer layer was laminated in a rectangular shape with a thickness of 3 mm and a width of 10 mm in a single layer by a 3D printer according to the method described in the examples. At this time, the contact area between the exposed portion of the plate surface and the material for forming the thermoplastic elastomer layer was about 125 mm 2They were laminated so as to achieve this. After that, the upper surface of the thermoplastic elastomer layer (the surface opposite to the plate containing the synthetic resin) was lined with an aluminum plate of 0.8 mm t to obtain a sample for measuring the tensile shear adhesion strength between the plate containing the synthetic resin and the thermoplastic elastomer layer. Based on JIS K 6850, a shear peel test was carried out on this sample at a test speed of 5 mm / min to evaluate the adhesion strength between the plate containing the synthetic resin and the thermoplastic elastomer layer.

[0078] 2. Measurement of the thickness of the thermoplastic elastomer layer The shape shown in Fig. 3 (thickness 3 mm, corner radius of curvature 20 mm) was formed in a spiral mode on a 15 cm square plate containing synthetic resin by a 3D printer using the method described in the examples, with only one layer. At that time, the formation was started from the formation start part shown in Fig. 3. Also, in the range of about 1 cm from the formation start part (the range of the masking part shown in Fig. 3), a packaging PP tape was attached to the plate in advance as a masking, and after the formation, the masking part was removed together with the thermoplastic elastomer layer. Regarding the obtained sample for measuring the thickness of the thermoplastic elastomer layer, as shown in Fig. 4, for the frame-shaped part of the thermoplastic elastomer layer, at the points (a) to (h) shown in Fig. 4, the total thickness including the thermoplastic elastomer layer was measured using a constant pressure thickness measuring machine, and the thickness of the plate containing the synthetic resin was subtracted to obtain the thickness of the thermoplastic elastomer layer at each point.

[0079] 3. Evaluation of sealing performance A 15 cm square plate containing synthetic resin was overlaid on the thermoplastic elastomer layer surface of the above sample for measuring the thickness of the thermoplastic elastomer layer, and while gently pressing it by hand, the gap between the plate / thermoplastic elastomer layer was visually confirmed, and the sealing performance was evaluated as follows. Sealing performance OK: No gap can be visually confirmed Sealing performance NG: A gap can be visually confirmed

[0080] <<Materials for forming the thermoplastic elastomer layer>> (Composition (a-1) containing an olefin rubber and a polyolefin resin) As a composition containing an olefin rubber and a polyolefin resin, TREXPLANE (registered trademark) 3555B manufactured by Mitsubishi Chemical Corporation was used. (Composition (a-2) containing a styrene copolymer rubber and a polyolefin resin) As a composition containing a styrene copolymer rubber and a polyolefin resin, TEFABLOCK (registered trademark) SJ4300C manufactured by Mitsubishi Chemical Corporation was used. (Composition (a-3) containing a styrene copolymer rubber and a polyolefin resin) As a composition containing a styrene copolymer rubber and a polyolefin resin, TEFABLOCK (registered trademark) TOSI212 40A manufactured by Mitsubishi Chemical Corporation was used. (Flame retardant (a-4)) As a flame retardant, an intumescent flame retardant containing 50 - 60% of piperazine pyrophosphate, 35 - 45% of melamine pyrophosphate, and 3 - 6% of zinc oxide with respect to the total mass of the phosphorus-based flame retardant composition, ADEKA STAB FP-2500S manufactured by ADEKA Corporation, was used. (Dispersant (a-5)) As a dispersant, an α-olefin·maleic anhydride copolymer (DIAKARNA 30M manufactured by Mitsubishi Chemical Corporation, weight average molecular weight 7,800) was used.

[0081] <Material (A-1) for forming a thermoplastic elastomer layer> As the material (A-1) for forming a thermoplastic elastomer layer, 58% by mass of component (a-1), 40% by mass of component (a-4), and 2% by mass of component (a-5) were blended and mixed by hand blending. Then, using a φ30 mm co-rotating twin-screw extruder (model name "BT-30", manufactured by Plastic Engineering Laboratory Co., Ltd., L / D = 30), after melt-kneading under the conditions of a screw rotation speed of 250 rpm and a cylinder temperature of 200°C, it was dried at 70°C for 12 hours to obtain pellets (A-1). "L / D" indicates the ratio of the length (L) to the diameter (D) of the screw.

[0082] <Material (A-2) for forming a thermoplastic elastomer layer> As the material (A-2) for forming the thermoplastic elastomer layer, pellets (A-2) were obtained in the same manner as the material (A-1) for forming the thermoplastic elastomer layer, except that 100% by mass of the component (a-1) was used.

[0083] <The material (A-3) for forming the thermoplastic elastomer layer> As the material (A-3) for forming the thermoplastic elastomer layer, pellets (A-3) were obtained in the same manner as the material (A-1) for forming the thermoplastic elastomer layer, except that 100% by mass of the component (a-2) was used.

[0084] <The material (A-4) for forming the thermoplastic elastomer layer> As the material (A-4) for forming the thermoplastic elastomer layer, pellets (A-4) were obtained in the same manner as the material (A-1) for forming the thermoplastic elastomer layer, except that 100% by mass of the component (a-3) was used.

[0085] <<The plate containing the synthetic resin>> (Synthetic resin (b-1)) As the synthetic resin, a polypropylene-based resin: "Novatec PP SA06GA" manufactured by Nippon Polypropylene Corporation (melt flow rate: 60 g / 10 min) was used. (Flame retardant (b-2)) As the flame retardant, an intumescent flame retardant containing 50 to 60% of piperazine pyrophosphate, 35 to 45% of melamine pyrophosphate, and 3 to 6% of zinc oxide with respect to the total mass of the phosphorus-based flame retardant composition, manufactured by ADEKA Corporation, Adeka Stab FP-2500S, a phosphorus-based flame retardant composition, was used. (Dispersant (b-3)) As the dispersant, an α-olefin / maleic anhydride copolymer (Daiyakarna 30M, manufactured by Mitsubishi Chemical Corporation, weight average molecular weight 7,800) was used. (Fiber (b-4)) As the fiber, a glass fiber mat obtained by needle punching a swirl (spiral) mat (basis weight 880 g / m 2 ) made from continuous roving glass fiber (fiber diameter 23 μm) was used.

[0086] The components (b-1), (b-2), and (b-3) were melt-kneaded (at 230 °C) at a ratio of 68% by mass, 30% by mass, and 2% by mass, respectively, to prepare pellets (B-1) of the resin composition. The above-mentioned pellets (B-1) were put into an extruder, melted, and then extruded into a sheet shape. Component (b-4) was sandwiched from both sides and laminated on the extruded sheet-shaped resin composition. Subsequently, sheet-shaped resin compositions were laminated on both surfaces, and while applying a pressure of 0.3 MPa using a laminator, heating and pressurization were performed at 230 °C for 4 minutes, and then cooling and solidification were carried out to obtain a plate (stampable sheet, thickness 2.5 mm) containing a synthetic resin.

[0087] (Example 1) The material (A-1) for forming a pellet-shaped thermoplastic elastomer layer was put into a 3D printer (GEM550 manufactured by S. Lab Co., Ltd.), and was discharged onto a plate containing a synthetic resin under the set conditions of a lamination pitch of 3 mm, a nozzle diameter of 6 mm, a nozzle temperature of 195 °C, a shaping speed of 20 mm / s, a discharge rate of 1.0, and a table temperature of 80 °C, and samples for measuring the tensile shear adhesion strength and samples for measuring the thickness of the thermoplastic elastomer layer were each shaped. The surface temperature of the plate containing the synthetic resin at this time was approximately 70 °C as measured by a contact thermometer. Also, the ratio of the area of the thermoplastic elastomer layer to the surface area of the plate containing the synthetic resin for the thermoplastic elastomer layer thickness and the sealability evaluation sample was approximately 18%. Using these samples, the adhesion strength, the thickness of the thermoplastic elastomer layer, and the sealability were each evaluated, and the results are shown in Table 1. In the adhesion strength evaluation, the peeling mode was cohesive failure of the material forming the thermoplastic elastomer layer.

[0088] (Example 2) The material for forming the thermoplastic elastomer layer was designated as (A-2). Samples for measuring the tensile shear adhesion strength and samples for measuring the thickness of the thermoplastic elastomer layer were respectively molded in the same manner as in Example 1, except that the nozzle temperature was 220°C and the discharge rate was 1.04. At this time, the surface temperature of the plate containing the synthetic resin was approximately 70°C as measured with a contact thermometer. Also, the ratio of the area of the thermoplastic elastomer layer to the surface area of the plate containing the synthetic resin for the samples for measuring the thickness of the thermoplastic elastomer layer and the sealability evaluation samples was approximately 18%. Using these samples, the adhesion strength, the thickness of the thermoplastic elastomer layer, and the sealability were respectively evaluated, and the results are shown in Table 1. In the adhesion strength evaluation, the peeling mode was cohesive failure of the material for forming the thermoplastic elastomer layer.

[0089] (Example 3) The material for forming the thermoplastic elastomer layer was designated as (A-3). Samples for measuring the tensile shear adhesion strength and samples for measuring the thickness of the thermoplastic elastomer layer were respectively molded in the same manner as in Example 1, except that the nozzle temperature was 220°C and the discharge rate was 1.04. At this time, the surface temperature of the plate containing the synthetic resin was approximately 70°C as measured with a contact thermometer. Also, the ratio of the area of the thermoplastic elastomer layer to the surface area of the plate containing the synthetic resin for the samples for measuring the thickness of the thermoplastic elastomer layer and the sealability evaluation samples was approximately 18%. Using these samples, the adhesion strength, the thickness of the thermoplastic elastomer layer, and the sealability were respectively evaluated, and the results are shown in Table 1. In the adhesion strength evaluation, the peeling mode was cohesive failure of the material for forming the thermoplastic elastomer layer.

[0090] (Example 4) The material for forming the thermoplastic elastomer layer was designated as (A-4). Samples for measuring the tensile shear adhesion strength and samples for measuring the thermoplastic elastomer layer thickness were respectively molded in the same manner as in Example 1, except that the nozzle temperature was 220°C and the discharge rate was 1.04. At this time, the surface temperature of the plate containing the synthetic resin was about 70°C as measured by a contact thermometer. Also, the ratio of the area of the thermoplastic elastomer layer to the surface area of the plate containing the synthetic resin for the thermoplastic elastomer layer thickness and the sealability evaluation sample was about 18%. Using these samples, the adhesion strength, the thermoplastic elastomer layer thickness, and the sealability were respectively evaluated, and the results are shown in Table 1. In the adhesion strength evaluation, the peeling mode was cohesive failure of the material forming the thermoplastic elastomer layer.

[0091] (Comparative Example 1) The discharge rate was 1.38, and the thermoplastic elastomer layer thickness measurement sample was molded in the same manner as in Example 2, except that the shape of the thermoplastic elastomer layer thickness measurement sample was the shape with right-angled corners shown in Fig. 5. Using this sample, the thermoplastic elastomer layer thickness and the sealability were respectively evaluated, and the results are shown in Table 1. Also, the molded appearance of this is shown in Fig. 6. The ratio of the area of the thermoplastic elastomer layer to the surface area of the plate containing the synthetic resin for this sample was about 18%. In this sample, unevenness occurred at the portion where the paths overlapped at the start and end points of the molding path. Also, at the right-angled corner portion, there was a retention of the material forming the thermoplastic elastomer layer in part, and the surface was uneven.

[0092] (Comparative Example 2) A silicone foam material with a thickness of 5 mm and a width of 8 mm, with a double-sided tape (product number: 93010LE) manufactured by 3M attached to one side, was prepared. The double-sided tape side of this was in contact with the plate containing the synthetic resin with a contact area of about 125 mm 2It was pasted so as to be, and a pressure of 2.0 MPa was applied from above the silicone foam for 24 hours. Then, the upper surface of the silicone foam (the surface opposite to the plate containing the synthetic resin) was lined with a 0.8 mmt aluminum plate, and in the same manner as in the examples, the adhesive strength between the silicone foam and the plate containing the synthetic resin was evaluated by a tensile shear test, and the results are shown in Table 1. In the adhesive strength evaluation, the peeling mode was interfacial peeling between the plate and the double-sided tape.

[0093]

Table 1

[0094] In Examples 1 to 4, since the difference between the maximum thickness and the minimum thickness of the thermoplastic elastomer layer is within the scope of the present application, the sealing property is excellent. Also, since the material forming the thermoplastic elastomer layer is directly adhesively bonded by heat fusion on the plate, the adhesive strength is excellent. On the other hand, in Comparative Example 1, the difference between the maximum thickness and the minimum thickness of the thermoplastic elastomer layer is larger than the scope of the present application, and the sealing property is inferior. Also, in Comparative Example 2, since the silicone foam is adhesively bonded to the plate via a double-sided tape, the adhesive strength is inferior.

[0095] <Evaluation of Material Recyclability> The plate containing the synthetic resin was cut into 10 cm × 10 cm, and on this plate, the material for forming the thermoplastic elastomer layer was laminated only in one layer by a 3D printer in the method described in the examples. This sample was put into a rotary cutter (RC250 type pulverizer manufactured by Yoshikou Co., Ltd.), and pulverized samples with a pulverization particle size of Φ1 mm were each prepared. The components of the pulverized samples were adjusted so as to be in the ratios shown in Table 2 below. In this evaluation, the "plate containing the synthetic resin" is the same as that used in Examples 1 to 4, and the "material for forming the thermoplastic elastomer layer" is pellets obtained in the same manner as the material (A-1) for forming the thermoplastic elastomer layer except that 100% by mass of the components described in Table 2 were used. The pulverized sample obtained above was added to the raw materials in Table 3, and molded products (Experimental Examples 1 to 2) were manufactured using an injection molding machine "FANUC ROBOSHOTα-S300iA" manufactured by FANUC Corporation. Also, a molded product (Experimental Example 3) was manufactured in the same manner as Experimental Examples 1 to 2 except that the pulverized sample was not included. The main molding conditions for the molded products (Experimental Examples 1 to 3) are as follows. 1) Temperature conditions: Cylinder temperature (220 °C), mold temperature (60 °C) 2) Injection conditions: Injection pressure (200 MPa), holding pressure (82 MPa) 3) Metering conditions: Screw rotation speed (50 rpm), back pressure (15 MPa)

[0096]

Table 2

[0097] 4. Evaluation of Flame Retardancy UL94 Using the molded products (1 / 16-inch test bars) prepared in each experimental example, the flame retardancy was evaluated by a vertical combustion test in accordance with the UL94 standard. The "total combustion time" is the sum of the flaming combustion times during the combustion test. The "number of drips" is the number of particles (drips) that fall from the test piece during the combustion test. The "judgment" is the grade determined by (1) the combustion time of each test piece after contact with the flame, (2) the total combustion time of 5 samples, (3) the combustion reach position of each test piece, (4) ignition by drips, and (5) red heat after the second contact with the flame, as defined in the UL94 standard.

[0098] 5. Measurement of Tensile Strength Using the molded products (JIS K7139-A1 or JIS K6251-1, dumbbell test pieces) prepared in each experimental example, the maximum tensile point strength (MPa) was measured in accordance with JIS K7161-1.

[0099] 6. Measurement of Flexural Strength The molded products (JIS K7139-A1 dumbbell test pieces) prepared in each experimental example were cut to a length of 80 mm, and the flexural modulus (MPa) and maximum flexural strength (MPa) were measured in accordance with JIS K7171.

[0100] The evaluation results of the molded products (Experimental Examples 1 to 3) obtained above are shown in Table 3.

[0101]

Table 3

[0102] From the results in Table 3, the recycled molded products containing the pulverized samples (Experimental Examples 1 to 2) were found to be comparable to the molded products without the pulverized samples (Experimental Example 3) in terms of both flame retardancy and mechanical properties. From this, it was confirmed that even when the pulverized material obtained by collecting and pulverizing the thermoplastic elastomer layer together was used as the raw material for the next molded product (recycled molded product), it could be molded without problems. In addition, when the flame retardancy and mechanical properties of the manufactured recycled molded products were confirmed, it was also confirmed that the performance was not impaired.

Industrial Applicability

[0103] The laminate of the present invention has high adhesive strength, excellent sealing properties, and is capable of material recycling. In particular, it is useful for battery packs using resin materials, which have been actively studied in recent years. Because of its high adhesive strength and excellent sealing properties, it has an excellent waterproof and dustproof effect. Moreover, since it can be recycled, it is expected to contribute to a sustainable society.

Explanation of Signs

[0104] 1 Electric vehicle 10 Chassis 10a Opening 15 Tire 20 Battery pack 21 Case 22 Upper case 23 Upper case body 24 Upper flange 32 Upper side wall 33 Top wall 42 Lower case 43 Lower case body 44 Lower flange 47 Lower side wall 48 Bottom wall 51 Power storage section 56 Fixing section 57 Bolt 58 Nut 61 Thermoplastic elastomer layer O1 Axis S1 Accommodation space

Claims

1. A laminate comprising a thermoplastic elastomer layer on one side of a plate containing a synthetic resin, the thermoplastic elastomer layer is in direct contact with the plate; the thermoplastic elastomer layer is formed of a material containing either or both of an olefin-based rubber or a polyolefin-based resin, The thermoplastic elastomer layer occupies 90% or less of the surface area of ​​the plate; A laminate, wherein the difference between the maximum thickness and the minimum thickness of the thermoplastic elastomer layer is 1.5 mm or less.

2. The laminate according to claim 1 , wherein the thermoplastic elastomer layer has a thickness of 10 mm or less.

3. The laminate of claim 1 , wherein the synthetic resin comprises a thermoplastic resin.

4. The laminate according to claim 1 , wherein the synthetic resin comprises a polyolefin-based resin.

5. 2. The laminate according to claim 1, wherein the plate is formed from a resin fiber composite material in which fibers are mixed with a synthetic resin.

6. The laminate of claim 5 , wherein the fibers comprise glass fibers.

7. The laminate according to claim 5 , wherein the resin fiber composite material is a stampable sheet.

8. The method for producing a laminate according to any one of claims 1 to 7, wherein the thermoplastic elastomer layer is heat fused to the plate.

9. The method for producing the laminate according to any one of claims 1 to 7, wherein the thermoplastic elastomer layer is formed by a three-dimensional additive manufacturing method.

10. A battery pack using the laminate according to any one of claims 1 to 7.

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