Method for producing molded article

Abstract

To provide a method for producing a molded article that exhibits high adhesive strength and superior sealing performance, and allows for material recycling.SOLUTION: A method for producing a molded article includes laminating a thermoplastic elastomer layer by thermal bonding on a structure including a thermoplastic resin, wherein the thermoplastic elastomer layer is composed of a material containing either or both of an olefin-based rubber and a polyolefin-based resin, and wherein the thermoplastic elastomer layer is laminated using a 3D printer such that the maximum-to-minimum thickness gap in the thermoplastic elastomer layer is 1.5 mm or less.SELECTED DRAWING: Figure 6

Description

Technical Field

[0001] The present invention relates to a method for manufacturing a molded body.

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 aimed 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, since 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 become issues, 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 the case, generally, the flange and the vulcanized rubber are adhered with an adhesive layer such as a double-sided tape. However, 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 method for manufacturing a molded body 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 method for manufacturing a molded body in which a thermoplastic elastomer layer is laminated by heat fusion on a structure containing a thermoplastic resin, wherein the thermoplastic elastomer layer is formed of a material containing either or both of an olefin rubber or a polyolefin resin, and the difference between the maximum thickness and the minimum thickness in the thermoplastic elastomer layer is 1.5 mm or less, and the thermoplastic elastomer layer is laminated using a 3D printer.

[0010] (2)Aspect 2 of the present invention may be the method for manufacturing a molded body according to (1), wherein the thermoplastic elastomer layer is directly laminated on the structure. (3)Aspect 3 of the present invention may be the method for manufacturing a molded body according to (1) or (2), wherein the thickness of the thermoplastic elastomer layer is 10 mm or less. (4)Aspect 4 of the present invention may be the method for manufacturing a molded body according to any one of (1) to (3), wherein the 3D printer is a material extrusion method (MEX method). (5)Aspect 5 of the present invention may be the method for manufacturing a molded body according to any one of (1) to (4), wherein the temperature at the time of laminating the thermoplastic elastomer layer is 170 to 260°C. (6)Aspect 6 of the present invention may be the method for manufacturing a molded body according to any one of (1) to (5), wherein the thermoplastic resin contains a polyolefin resin. (7)Aspect 7 of the present invention may be the method for manufacturing a molded body according to any one of (1) to (6), wherein the structure has a three-dimensional shape. (8)Aspect 8 of the present invention may be the method for manufacturing a molded body according to any one of (1) to (7), wherein the structure is formed of a resin fiber composite material in which fibers are mixed with a thermoplastic resin. (9)Aspect 9 of the present invention may be the method for manufacturing a molded body according to (8), wherein the fibers contain glass fibers. (10)Aspect 10 of the present invention may be the method for manufacturing a molded body according to any one of (1) to (9), which is used for a battery pack.

Advantages of the Invention

[0011] According to the present invention, it is possible to provide a method for manufacturing a molded body having high adhesive strength, excellent sealing properties, and 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] <<Molded Body>> The molded body of the present invention (hereinafter, also referred to as "the present molded body") includes a thermoplastic elastomer layer on a structure containing a thermoplastic resin. That is, the present molded body includes a structure containing a thermoplastic resin and, on one side of the structure containing a thermoplastic resin, a thermoplastic elastomer layer.

[0015] <Structure Containing Thermoplastic Resin> The present molded body includes a structure containing a thermoplastic resin. 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. The thermoplastic resin may be a single resin or a composite resin of two or more resins.

[0016] The content of the thermoplastic resin in the structure is not particularly limited, but is preferably 15 to 80% by mass. When the content of the thermoplastic resin is 15% by mass or more, the molding processability 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 thermoplastic resin is more preferably 35 to 70% by mass, and even more preferably 40 to 60% by mass.

[0017] 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 viewpoints, the MFR is more preferably 50 to 400 g / 10 min, even 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] As the thermoplastic resin, it is more preferable to contain a polyolefin-based resin. In the present invention, the "polyolefin-based 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-based resin is preferably 95 mol% or more, more preferably 98 mol% or more. Examples of the polyolefin-based resin include α-olefin polymers such as polyethylene, polypropylene, polybutene, poly(3-methyl-1-butene), poly(3-methyl-1-pentene), poly(4-methyl-1-pentene); α-olefin copolymers such as ethylene-propylene block or random copolymer, α-olefin-propylene block or random copolymer having 4 or more carbon atoms, ethylene-methyl methacrylate copolymer, ethylene-vinyl acetate copolymer; cycloolefin polymers such as polycyclohexene and polycyclopentene. Examples of polyethylene include low-density polyethylene, linear low-density polyethylene, and high-density polyethylene. Examples of polypropylene include isotactic polypropylene, syndiotactic polypropylene, hemi-isotactic polypropylene, and stereoblock polypropylene. 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, and 4-methyl-1-pentene. These polyolefin-based resins may be used alone or in combination of two or more.

[0019] From the viewpoint of recyclability, the polyolefin-based resin preferably contains polypropylene. Polypropylene and other polyolefin resins may be used in combination. 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] The structure containing the thermoplastic 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, phosphorus-based flame retardants are preferred. 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] The phosphorus-based flame retardant is a phosphorus compound, that is, a compound containing a phosphorus atom in the 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)phosphates, (poly)phosphoric acid esters, 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 preferred 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. Also, 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, etc. These (poly)phosphates may be used alone or in combination of two or more.

[0023] Among 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. The formation of the surface expansion layer suppresses the diffusion of decomposition products and heat transfer, 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 Adeka Stab FP-2100J, FP-2200, and FP-2500S (manufactured by ADEKA).

[0025] When the structure contains a flame retardant, the content of the flame retardant in the structure 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, a sufficient amount of other components (thermoplastic resin, dispersant and fiber described later, etc.) can be contained, and for example, good moldability 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 structure may contain a dispersant in order to enhance the dispersibility of the flame retardant in the thermoplastic resin. The dispersant is not particularly limited as long as it can disperse the flame retardant in the thermoplastic resin, but 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 a phosphorus-based flame retardant suitable as a flame retardant is used, a copolymer of an α-olefin and an unsaturated carboxylic acid (hereinafter also referred to as a "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 resin, which is particularly suitable as a thermoplastic 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 a 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 carbon number of the α-olefin is 5 or more, the compatibility with the thermoplastic resin tends to be better. If it is 80 or less, it is advantageous in terms of raw material cost. The carbon number 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 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 anhydrides are preferred from the viewpoint of copolymerization reactivity. Among them, dicarboxylic anhydrides are preferred, and maleic anhydride is particularly preferred, from the viewpoint of compatibility with phosphorus-based flame retardants which are 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. If 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 structure 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 structure 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 structure containing a thermoplastic resin may be formed from a resin fiber composite material (fiber reinforcing material) in which fibers are mixed with the thermoplastic resin. For example, a resin composition containing fibers such as glass fibers and carbon fibers in the thermoplastic resin may be used, or the thermoplastic resin may be impregnated with fibers such as glass fibers and carbon fibers. 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 can be mentioned. These inorganic fibers may be used alone or in combination of two or more. Among the inorganic fibers, it is preferable to contain glass fibers from the viewpoints of flame shielding property and processability. That is, it is preferable that the fibers contain glass fibers.

[0034] When the structure contains fibers, the content of the fibers in the structure 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, production 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 thermoplastic resin is more preferable. When the structure contains a flame retardant and a dispersant, it is preferable to produce a stampable sheet by impregnating a mat made of fibers with a resin composition containing a thermoplastic resin, a flame retardant, a dispersant, optional additives, etc., excluding the fibers. As a method for producing the resin composition, a conventionally known method can be used, and it can be produced by blending the above components and mixing and melt-kneading them. Mixing is performed using a mixer such as a tumbler, V blender, or ribbon blender, and melt-kneading is performed using equipment such as a single-screw extruder, twin-screw extruder, Banbury mixer, roll mixer, Brabender plastograph, kneader, etc., and is melt-kneaded and granulated. Also, as a method of impregnation, there are a method of applying a thermoplastic resin or a resin composition to a mat made of fibers, a method of preparing a sheet of a thermoplastic 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] The structure may be in the form of a sheet or a plate, or may be in the form of a case. Also, the structure may be in a flat shape, or may be shaped into a three-dimensional shape in part or in whole by hot pressing or the like. Among them, the structure is preferably in a three-dimensional shape. When the structure is in the form of a case, the manufacturing method may be, for example, to form the above stampable sheet 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 press mold them.

[0037] <Thermoplastic elastomer layer> This molded article includes a thermoplastic elastomer layer. The material for forming the thermoplastic elastomer layer may be rubber alone or a composition containing rubber and a thermoplastic resin, and preferably is a composition containing rubber and a thermoplastic resin. Among them, from the viewpoint of recycling, it is preferable that the material contains either or both of an olefin rubber or a polyolefin resin. Since the thermoplastic elastomer layer is formed of an elastomer containing either or both of an olefin rubber or a polyolefin resin excellent in recyclability, it is possible to perform melting and reformation by reheating after use and material recycle as a new product such as a recycled molded article.

[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. Further, the olefin rubber may be used alone or in combination of two or more kinds.

[0039] Olefin rubber may have other monomer units such as monomer units based on non-conjugated dienes (non-conjugated diene units) in addition to ethylene units and α-olefin units having 3 to 8 carbon atoms. 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, and 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, and 6-chloromethyl-5-isopropenyl-2-norbornene. Preferably, they are 5-ethylidene-2-norbornene and dicyclopentadiene. Furthermore, ethylene-propylene copolymers, ethylene-propylene-diene copolymers, and ethylene-butene copolymers may be partially or completely crosslinked. Among them, from the viewpoints of moldability and rubber elasticity, partial crosslinking is preferred.

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

[0041] As the polyolefin resin, crystalline polyolefin is preferred 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 obtained by modifying the crystalline polyolefin 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-based polymers, ethylene-based polymers, and the like. These may be used alone or in combination of two or more.

[0043] Examples of the propylene-based polymer include a propylene homopolymer, and a propylene-based copolymer which is a random or block copolymer of polypropylene and an α-olefin such as ethylene, 1-butene, or 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] It is also possible to use commercially available corresponding products for the propylene-based polymer. Commercially available polypropylenes can be procured from manufacturers listed below and can be appropriately selected. Commercially available products that can be obtained include Novatec (registered trademark) PP from Nippon Polypropylene Corporation, Prime Polypro (registered trademark) from Prime Polymer Co., Ltd., Sumitomo Nolen (registered trademark) from Sumitomo Chemical Co., Ltd., polypropylene block copolymer from Sun Allomer Co., Ltd., Moplen (registered trademark), Circluen from LyondellBasell Industries, ExxonMobil PP from ExxonMobil Corporation, Formolene (registered trademark) from Formosa Plastics Corporation, Borealis PP from Borealis AG, SEETEC PP from LG Chem Ltd., ASI POLYPROPYLENE from A. Schulman, Inc., INEOS PP from INEOS Olefins & Polymers, Braskem PP from Braskem S.A., Sumsung Total from SAMSUNG TOTAL PETROCHEMICALS CO., LTD., Sabic (registered trademark) PP from SABIC, TOTAL PETROCHEMICALS Polypropylene from TOTAL PETROCHEMICALS, YUPLENE (registered trademark) from SK Corporation, and the like.

[0045] Examples of the ethylene polymer include high-density polyethylene, low-density polyethylene, and linear low-density polyethylene. The density of the ethylene polymer measured by JIS K 7112 is preferably in the range of 0.910 g / cm 3 to 1.00 g / cm 3 or less from the viewpoint of achieving both 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, excellent moldability can be achieved, the appearance of the resulting thermoplastic elastomer layer can be improved, and the mechanical properties can be controlled within a desired range.

[0046] The molecular weights of the above-mentioned propylene-based polymer and ethylene-based polymer are not particularly limited, but it is preferable to include 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. In addition, 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 or 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 the hydrocarbon-based softening agent for rubber include mineral oil-based softening agents and synthetic resin-based softening agents, and mineral oil-based softening agents are particularly preferred. Mineral oil-based softening agents are generally mixtures of aromatic hydrocarbons, naphthenic hydrocarbons, and paraffinic hydrocarbons. Those in which more than 50% of the total carbon atoms are paraffinic hydrocarbons are called paraffin oils, those in which 30 to 45% of the total carbon atoms are naphthenic hydrocarbons are called naphthenic oils, and those in which 35% or more of the total carbon atoms are aromatic hydrocarbons are called aromatic oils. Among these, paraffin oils are preferred.

[0049] The kinematic viscosity at 40°C of the hydrocarbon-based softening agent 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. Further, the flash point (COC method) of the hydrocarbon-based softening agent for rubber is preferably 200°C or more, more preferably 250°C or more.

[0050] As the hydrocarbon-based softening agent for rubber, commercially available products 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 softening agent for rubber can be used alone as only one type, or in any combination and ratio of two or more types.

[0052] As the composition containing an olefin-based rubber and a polyolefin-based resin, commercially available products can also be used. For example, Milastomer (Registered Trademark) manufactured by Mitsui Chemicals, Inc., the 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, Tefablock (Registered Trademark) TPO manufactured by Mitsubishi Chemical Corporation, Santoprene (Registered Trademark) manufactured by Celanese, Sarlink (Registered Trademark) manufactured by Toyobo EMS Co., Ltd., Dawnprene (Registered Trademark) manufactured by Shandong Dawn Polymer, etc.

[0053] As the composition containing a styrene-based copolymer rubber and a polyolefin-based 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 Co., Ltd., Elastomer AR (registered trademark) manufactured by Aron Kasei Co., Ltd., Allostomer (registered trademark) manufactured by Aron Kasei Co., Ltd., Ernestone (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 the 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 structure containing a thermoplastic resin can preferably be 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 structure containing a thermoplastic resin can preferably be used. When the material for forming the thermoplastic elastomer layer contains a flame retardant or a dispersant, the ratio of the rubber alone and / or the composition containing rubber and a thermoplastic resin 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 ratio 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, and if it is at most the above upper limit value, it is more excellent in flame retardancy. The proportion of the flame retardant relative to the total mass of the material 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 or above the lower limit value, the flame retardancy is more excellent. If it is at or below the upper limit value, the original physical properties of the rubber alone and / or the composition containing rubber and thermoplastic resin (for example, high mechanical properties and flexibility) are likely to be exhibited. The proportion of the dispersant relative to the total mass of the material 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 or above the lower limit value, the flame retardant is well dispersed, and the flame retardancy, high flexibility, mechanical properties of the material forming the thermoplastic elastomer layer, and the appearance of the obtained thermoplastic elastomer layer are good. If the proportion of the dispersant is at or below the upper limit value, the influence of the dispersant on the flame retardancy of the material forming the thermoplastic elastomer layer can be suppressed.

[0055] In addition, conductivity may be imparted to the thermoplastic elastomer layer in order to shield electromagnetic waves. For example, a composition containing rubber alone and / or a composition containing rubber and thermoplastic resin as the material forming the thermoplastic elastomer layer and a conductive agent may be used, or the composition containing the material forming the thermoplastic elastomer layer and the conductive agent may be two-color molded. 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, it can be sufficiently mixed using preliminary mixing means such as a V-type blender, a Henschel mixer, a mechanochemical device, an extrusion mixer, etc., granulated by an extrusion granulator or a briquetting machine as the case may be, and then melt-kneaded and extruded by a melt-kneading machine. 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 shafts, 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 and pelletized, or cooled to form a strand, and then the strand is cut by a device such as a pelletizer and pelletized.

[0057] The thermoplastic elastomer layer is obtained by molding the material for forming the thermoplastic elastomer layer. The molding method is three-dimensional laminated molding. The three-dimensional laminated molding method is molding by a 3D printer. That is, the thermoplastic elastomer layer is laminated on a structure using 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 granule-shaped molding materials. Examples of such printers include those that control the drive of the extrusion nozzle in a gantry manner and those that control it in a robot arm manner. The temperature for molding the material for forming the thermoplastic elastomer layer, that is, the temperature for laminating the thermoplastic elastomer layer, is preferably 170 to 260 °C.

[0058] This molded body has a thermoplastic elastomer layer laminated on the structure by heat fusion. As a method for manufacturing such a molded body, for example, there are a method of integrating with the structure after molding a single thermoplastic elastomer layer by three-dimensional laminated modeling and a method of directly laminating on the structure. By taking such a method, there is an advantage that it is not necessary to provide an adhesive layer, and a molded body having high adhesive strength and excellent sealing property is obtained. Also, the thermoplastic elastomer layer is preferably directly laminated on the structure. By taking such a method, it is also possible to integrally mold the structure and the thermoplastic elastomer layer to obtain a molded body. At this time, for the purpose of improving the heat fusion property, the structure may be heated before or during molding by a 3D printer. This heating temperature is, for example, 40 to 160 °C.

[0059] As a particularly preferred embodiment of the present invention, it is formed from a structure containing a polyolefin-based resin as the thermoplastic resin, and the thermoplastic elastomer layer is formed from a material containing either or both of an olefin-based rubber or a polyolefin-based resin. That is, by forming the thermoplastic elastomer layer and the structure from the same polyolefin-based material, it becomes possible to perform material recycling of the thermoplastic elastomer layer and the structure together after use. As another preferred embodiment, the thermoplastic elastomer layer is formed of a material containing an acid-modified polyolefin-based thermoplastic elastomer, and the structure is formed from a structure containing a polyamide resin as the thermoplastic resin.

[0060] In this molded body, it is preferable that the thermoplastic elastomer layer occupies an area of 90% or less with respect to the surface area of the structure. By adhering the thermoplastic elastomer layer so as to occupy an area of 90% or less with respect to the surface area of the structure, it becomes possible to use the minimum amount of material necessary for the manifestation of the sealing effect, and there are effects such as weight reduction and cost reduction. On the other hand, by adhering so as to preferably occupy an area of 0.1% or more with respect to the surface area of the structure, sufficient sealing performance can be exhibited. From such a viewpoint, it is preferable that the thermoplastic elastomer layer occupies an area of 80% or less with respect to the surface area of the structure, 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, the thermoplastic elastomer layer does not float from the structure, and the sealing performance is excellent. Further, even when another material is adhered to the surface of the thermoplastic elastomer layer opposite to the structure, the thermoplastic elastomer layer is not uneven and the sealing performance 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 viewpoint, 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, optimization of the shaping shape, shaping path, discharge amount, discharge width, etc. can be mentioned when molding by a 3D printer. For example, when the shaping path is a shape that bends at a right angle or an acute angle, resin stays at the bent 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 performance so that no gap is generated 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 molded body. The molded body 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 the molded body corresponds to the thermoplastic elastomer layer 61, and the structure containing the thermoplastic resin corresponds to the upper case 22 and / or the lower case 42. Further, the laminated portion of the thermoplastic elastomer layer and the structure 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 tire 15 is rotatably supported by the chassis 10 via a suspension (not shown). The motor rotates the tire 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 it 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 rectangular tubular shape with a rectangular edge when viewed in the vertical direction. The bottom wall 48 closes the opening formed at the lower end of the lower side wall 47.

[0070] The lower flange 44 projects outward along the 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 separated 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 installed in the same manner 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 power and supplies this 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 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 bolt 57 is passed through the through holes of the upper case 22, the through holes of the lower case 42, and the through holes of the chassis 10, respectively. Nut 58 is in contact with the lower flange 44 of the lower case 42 from below the lower flange 44. Nut 58 is fitted onto the shaft portion of bolt 57. The head of bolt 57 and 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 modified in its configuration as described below. In the battery pack of the first modification example, in each component 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 with reference to 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 Adhesion Strength A structure containing a thermoplastic resin was cut into 10 cm × 20 cm, and after covering the surface with a polyimide (PI) sheet, only a part of the PI sheet was removed so as to form a strip having a width of 1.25 cm in the longitudinal direction to expose the surface of the structure. On this structure, 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 surface of the structure and the material for forming the thermoplastic elastomer layer was about 125 mm 2They were laminated so as to achieve this. Then, the upper surface of the thermoplastic elastomer layer (the surface opposite to the structure containing the thermoplastic resin) was lined with an aluminum plate of 0.8 mmt to obtain a sample for measuring the tensile shear adhesion strength between the structure containing the thermoplastic 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 structure containing the thermoplastic resin and the thermoplastic elastomer layer.

[0078] 2. Measurement of the thickness of the thermoplastic elastomer layer The shape shown in Figure 3 (thickness 3 mm, corner radius of curvature 20 mm) was formed in a single layer on a 15 cm square structure containing a thermoplastic resin by a 3D printer in spiral mode according to the method described in the examples. At that time, the shaping was started from the shaping start part shown in Figure 3. Also, in the range of about 1 cm from the shaping start part (the range of the masking part shown in Figure 3), a packaging PP tape was affixed in advance on the structure as a mask, and after shaping, 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 Figure 4, for the frame-shaped part of the thermoplastic elastomer layer, at the points (a) to (h) shown in Figure 4, the total thickness including the thermoplastic elastomer layer was measured using a constant-pressure thickness measuring machine, and the thickness of the structure containing the thermoplastic 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 structure containing a thermoplastic 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 by hand, the gap between the structure / 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 (manufactured by Mitsubishi Chemical Corporation, DIACARNA 30M, 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 structure containing a thermoplastic resin>> (The thermoplastic resin (b-1)) As the thermoplastic resin, a polypropylene-based resin: "Novatec PP SA06GA" manufactured by Nippon Polypropylene Corporation (melt flow rate: 60 g / 10 min) was used. (The 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. (The dispersant (b-3)) As the dispersant, an α-olefin·maleic anhydride copolymer (manufactured by Mitsubishi Chemical Corporation, Dyne Carnal 30M, weight average molecular weight 7,800) was used. (The 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 fibers (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 pellets (B-1) were put into an extruder, melted, and then extruded into a sheet shape. Component (b-4) was sandwiched and laminated on both sides of the extruded sheet-shaped resin composition. Next, 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 structure (stampable sheet, thickness 2.5 mm) containing a thermoplastic 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 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, it was discharged onto a structure containing a thermoplastic resin, and samples for measuring the tensile shear adhesion strength and samples for measuring the thickness of the thermoplastic elastomer layer were each shaped. At this time, the surface temperature of the structure containing the thermoplastic resin 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 structure containing the thermoplastic resin for the thermoplastic elastomer layer thickness and sealability evaluation samples 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 for 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 structure containing the thermoplastic 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 structure containing the thermoplastic resin for the thermoplastic elastomer layer thickness and 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 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 structure containing the thermoplastic 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 structure containing the thermoplastic resin for the thermoplastic elastomer layer thickness and 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 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 thickness of the thermoplastic elastomer layer were each 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 structure containing the thermoplastic 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 structure containing the thermoplastic 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.

[0091] (Comparative Example 1) The thermoplastic elastomer layer thickness measurement sample was molded in the same manner as in Example 2, except that the discharge rate was 1.38 and 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 thickness of the thermoplastic elastomer layer and the sealability were each evaluated, and the results are shown in Table 1. Also, the external appearance of the molding is shown in FIG. 6. The ratio of the area of the thermoplastic elastomer layer to the surface area of the structure containing the thermoplastic resin for this sample was approximately 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 some retention of the material forming the thermoplastic elastomer layer, 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 structure containing the thermoplastic resin with a contact area of approximately 125 mm 2It was pasted so as to become, 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 structure containing the thermoplastic resin) was lined with an aluminum plate of 0.8 mm t, and in the same manner as in the examples, the adhesive strength between the silicone foam and the structure containing the thermoplastic 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 structure and the double-sided tape.

[0093]

Table 1

[0094] In the methods of 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, and since the material forming the thermoplastic elastomer layer is directly heat-sealed and adhered onto the structure, a molded body excellent in adhesive strength has been obtained. On the other hand, in the method of Comparative Example 1, since the difference between the maximum thickness and the minimum thickness of the thermoplastic elastomer layer is larger than the scope of the present application, a molded body inferior in sealing property has been obtained. Further, in Comparative Example 2, since the silicone foam is adhered onto the structure via a double-sided tape to produce a molded body, the adhesive strength is inferior.

[0095] <Evaluation of Material Recyclability> The structure containing the thermoplastic resin was cut into 10 cm × 10 cm, and on this structure, the material 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 pulverizing device manufactured by Yoshikou Co., Ltd.), and pulverized samples with a pulverization particle size of Φ1 mm were produced respectively. The components of the pulverized samples were adjusted so as to be in the ratios shown in Table 2 below. In this evaluation, the "structure containing the thermoplastic resin" is the same as that used in Examples 1 to 4, and the "material forming the thermoplastic elastomer layer" is pellets obtained in the same manner as the material (A-1) 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 a grade determined by (1) the combustion time after the test piece is exposed to 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 exposure to 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 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 (Experimental Examples 1 to 2) containing the pulverized sample were found to be comparable to the molded products (Experimental Example 3) without the pulverized sample 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 method for manufacturing the molded body 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 that 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 method for producing a molded article in which a thermoplastic elastomer layer is laminated by heat fusion onto a structure containing a thermoplastic resin, comprising the steps of: the thermoplastic elastomer layer is formed of a material containing either or both of an olefin-based rubber or a polyolefin-based resin, A method for producing a molded body, comprising laminating the thermoplastic elastomer layers using a 3D printer so that the difference between the maximum thickness and the minimum thickness of the thermoplastic elastomer layers is 1.5 mm or less.

2. The method for producing a molded article according to claim 1 , wherein the thermoplastic elastomer layer is directly laminated on the structure.

3. The method for producing a molded article according to claim 1 , wherein the thermoplastic elastomer layer has a thickness of 10 mm or less.

4. The method for producing a molded body according to claim 1 , wherein the 3D printer is a material extrusion type (MEX type).

5. The method for producing a molded article according to claim 1, wherein the temperature when laminating the thermoplastic elastomer layer is 170 to 260°C.

6. The method for producing a molded article according to claim 1 , wherein the thermoplastic resin comprises a polyolefin resin.

7. The method for producing a molded article according to claim 1 , wherein the structure has a three-dimensional shape.

8. The method for producing a molded article according to claim 1 , wherein the structure is formed from a resin fiber composite material in which fibers are mixed with a thermoplastic resin.

9. The method for producing a molded article according to claim 8 , wherein the fibers include glass fibers.

10. The method for producing the molded article according to any one of claims 1 to 9, which is used for a battery pack.

Images