JP2024041073A - battery housing - Google Patents

Abstract

To provide a battery housing excellent in flame retardance and especially excellent in flame-interruption.SOLUTION: A battery housing includes a resin layer containing a flame retardant and a support layer layered on at least one surface of the resin layer. The resin layer and the support layer are arranged in this order from a battery storage part side.SELECTED DRAWING: None

Description

The present invention relates to a battery housing, and more particularly to a battery housing with excellent flame retardant and flame-blocking properties.

In recent years, research and development of electric vehicles and hybrid vehicles has been progressing as part of environmental measures, and efforts are being made to develop batteries with high energy density and reduce weight with the aim of increasing cruising range. Batteries with such high energy density are at risk of catching fire due to an unexpected accident, and as a safety measure for passengers, the housing material must have high flame-retardant properties, so metal materials such as iron and fire-resistant materials are used in combination. There are many cases.
However, metal materials have the disadvantage of being heavy, and when refractory materials are used in combination, there are problems with workability and cost increases due to an increase in the number of parts. Therefore, attempts have been made to use resin, which has the potential to achieve both weight reduction and flameproofing properties.
On the other hand, carbon dioxide reduction and recyclability are currently being emphasized in order to create a sustainable society. Many thermosetting materials have high flame retardancy and are commonly used as composite materials, but thermoplastic resin materials are advantageous in terms of recyclability.

In addition, in China, a safety standard called GB 38031-2020 (Safety Requirements for Electric Vehicle Power Batteries) has been announced, which requires a warning to be issued 5 minutes before battery thermal runaway occurs. It is believed that this can also be achieved by using a housing material that blocks flames for 5 minutes or more after ignition.

To address these problems, for example, Patent Document 1 proposes a carbon fiber-reinforced polypropylene resin in which a brominated flame retardant or an antimony oxide compound is added. However, the additives used here have biopersistence problems.
On the other hand, Patent Document 2 discloses a flame-retardant polyolefin composition in which a polyolefin resin contains a (poly)phosphate compound as a technique for making polypropylene resin flame retardant in consideration of bioresistance. things are being proposed.
Further, Patent Document 3 proposes a flame-retardant resin composition containing long glass fibers and a phosphate compound in a polypropylene resin.

Japanese Patent Application Publication No. 2014-62189 Japanese Patent Application Publication No. 2013-119575 Japanese Patent Application Publication No. 2011-88970

As described above, conventional techniques have many insufficiencies in the use of resin, which has the potential to reduce the weight of high-energy-density batteries and provide flame-retardant properties. Specifically, in the carbon fiber-reinforced polypropylene resin composition disclosed in Patent Document 1, there is a problem with bioresistance in the additives used, and the carbon fiber length indicated in the patent document is insufficient to form a molded article. There is a problem that sufficient strength and rigidity cannot be obtained.
In addition, in the resin composition disclosed in Patent Document 2, the phosphorus flame retardant has poor dispersibility, and although flame retardancy can be obtained by adding a large amount of the phosphorus flame retardant, the resin composition has significantly higher strength than the polypropylene resin. There are issues that cause a decline. Furthermore, when a battery housing contains a large amount of flame retardant, there is a problem that molding defects (unfilled molding) are likely to occur during molding.
Furthermore, like Patent Document 2, the flame-retardant resin composition disclosed in Patent Document 3 needs to contain a large amount of phosphorus-based flame retardant, and maintains the mechanical properties of the battery housing and fluidity during molding. The problem is that it can't be done.
As described above, the flame-retardant resin compositions disclosed in Patent Documents 2 and 3 do not have sufficient flame retardancy when trying to ensure the mechanical properties of battery housings and the fluidity during molding, and especially Insufficient against flammability.

The present invention has been made in order to solve the above-mentioned problems, and an object of the present invention is to provide a battery housing that is excellent in flame retardancy, particularly in flameproofing properties.

In order to solve the above problems, the present inventors have conducted intensive studies and determined the arrangement of a battery housing having a resin layer containing a flame retardant and a support layer on at least one side of the resin layer from the battery housing side. We have found that the above problems can be solved by doing so. The present invention was completed based on these findings. That is, the present invention provides the following [1] to [17].
[1] A battery housing comprising a resin layer containing a flame retardant and a support layer laminated on at least one surface of the resin layer, the resin layer and the support layer being arranged in this order from the battery housing side. The battery housing is characterized by:
[2] According to claim 1, the resin layer is made of a resin composition containing (A) a thermoplastic resin and (B) a flame retardant, and the support layer is a fiber layer made of fibers (X). battery housing.
[3] The battery housing according to [2] above, wherein the fiber layer is a nonwoven fabric layer made of a nonwoven fabric, a woven fabric layer made of a woven fabric, or a knitted fabric layer made of a knitted fabric.
[4] The battery housing according to [2] or [3] above, wherein the fibers (X) constituting the fiber layer have an average fiber length of 5 to 100 mm.
[5] The battery housing according to any one of [2] to [4] above, wherein the resin composition further contains (C) fibers, and the average fiber length of the fibers is 5 to 100 mm.
[6] The battery housing according to any one of [2] to [5] above, wherein the resin composition further contains (D) a dispersant.
[7] The battery housing according to any one of [1] to [6] above, wherein the resin layer has a thickness of 0.5 to 50 mm.
[8] The battery housing according to any one of [2] to [7] above, wherein the flame retardant (B) includes a phosphorus-based flame retardant.
[9] The battery housing according to any one of [2] to [7] above, wherein the flame retardant (B) includes an intumescent flame retardant.
[10] The battery housing according to any one of [2] to [9] above, wherein the fiber (X) constituting the fiber layer contains inorganic fiber.
[11] The battery housing according to [10] above, wherein the inorganic fibers constituting the fiber layer include at least one selected from the group consisting of glass fibers, ceramic fibers, metal fibers, and metal oxide fibers.
[12] The battery housing according to any one of [5] to [11] above, wherein the fiber (C) contains an inorganic fiber.
[13] The battery housing according to [12] above, wherein the inorganic fiber includes at least one selected from the group consisting of glass fiber, ceramic fiber, metal fiber, and metal oxide fiber.
[14] The battery housing according to [6] above, wherein the dispersant (D) contains a copolymer of an α-olefin and an unsaturated carboxylic acid.
[15] Any one of [2] to [14] above, wherein the thermoplastic resin (A) contains a polypropylene resin, and the content of the polypropylene resin in the resin composition is 15 to 80% by mass. Battery housing as described.
[16] The battery housing according to any one of [2] to [15] above, wherein the content of the flame retardant (B) in the resin composition is 1 to 40% by mass.
[17] The content of the dispersant (D) is 0.1 to 20 parts by mass based on 100 parts by mass of the flame retardant (B), according to any one of [6] to [16] above. battery housing.

According to the present invention, it is possible to provide a battery housing that has excellent flame retardancy, particularly excellent flame blocking properties.

FIG. 2 is a conceptual diagram showing the structure of a battery. FIG. 1 is a schematic diagram showing one embodiment of a laminate that constitutes a battery housing of the present invention. FIG. 3 is a schematic diagram showing the positional relationship between a laminate and a flame that constitute the battery housing of the present invention. It is a schematic diagram which shows another aspect of the laminated body which comprises the battery housing of this invention. It is a schematic diagram which shows another aspect of the laminated body which comprises the battery housing of this invention. FIG. 2 is a schematic diagram showing an example of a method for manufacturing a laminate that constitutes the battery housing of the present invention. FIG. 2 is a schematic diagram showing an overview of flame contact evaluation in an example of the present invention.

Hereinafter, embodiments of the present invention will be described in detail. However, the following description is an example of the embodiments of the present invention, and the present invention is not limited to these contents at all.

[Battery housing]
FIG. 1 is a conceptual diagram showing the structure of a battery including a battery housing. The battery 100 includes a battery module 110 that is an assembly of battery cells (single batteries), a battery pack 120 that is an assembly of battery modules, and a battery housing 130 for housing battery members such as the battery pack.
As schematically shown in FIG. 2, the battery housing 130 of the present invention is made of a laminate 10 including a resin layer 12 containing a flame retardant and a support layer 11 laminated on at least one surface of the resin layer. Become. The resin layer 12 and the support layer 11 are arranged in this order from the battery storage section side, that is, from the battery pack 120 side.

As described above, in the battery housing of the present invention, since the resin layer 12 is located on the battery housing side, the resin layer 12 comes into contact with the flame when the battery module 110 ignites. The mechanism by which the battery housing of the present invention blocks flames is considered as follows. In addition, in the battery housing of the present invention, the resin layer 12 contains a flame retardant 13, and preferably contains fibers 14, as will be described in detail later.

<Mechanism of flame blocking action>
The battery housing 130 of the present invention is constituted by a laminate 10, and as schematically shown in FIG. 3, a resin layer 12 is held by a support layer 11. Therefore, when the resin layer 12 comes into contact with the flame, the resin layer is prevented from melting and falling. It is considered that the char (carbonized film) formed by the flame retardant 13 coming into contact with the flame is stably formed in the resin layer. If the resin layer and the support layer are arranged in this order from the battery housing side, in the event that the battery ignites abnormally, the resin layer will come into contact with the flame before the support layer. In this case, the resin layer fully functions as a heat insulating layer during flame contact, and the support layer can be effectively protected from high heat. Therefore, since the temperature of the support layer does not rise to the softening point due to the heat insulating effect of the char, the support layer can exist stably, and the retention effect of the resin layer is maintained. As a result, the flame does not appear to penetrate for long periods of time.

In particular, since the laminate 10, which is a preferred embodiment, includes the fibers 14 in the resin layer 12, it is thought that the flame retardant 13 exists in a uniformly dispersed manner. Since the flame retardant is uniformly dispersed in the resin between the fibers, the char formed when the flame retardant comes into contact with the flame is fixed in the gaps between the fibers. Furthermore, the size of the char that expands and is formed upon contact with the flame is limited by the gaps between the fibers, so that the size of the char that is formed becomes uniform. It is thought that the combination of the effect of fixing the char by the fibers and the uniformity of the size of the char results in the formation of a dense char, which significantly improves the flame-retardant properties of the laminate. In particular, by setting the content ratio of dispersant to flame retardant within a specific range, the flame retardant can be controlled to exist uniformly in the resin between the fibers, and the flame retardant properties of the laminate can be significantly improved. It seems that you will get it.
As described above, by arranging the resin layer and the support layer in this order from the battery housing side, the battery housing of the present invention has a flame blocking effect.

The mechanism by which the battery housing of the present invention blocks flames is presumed as described above, and therefore, in the battery housing of the present invention, the resin layer functions as a flame-retardant heat insulating layer when exposed to flame. preferable.

<Other aspects of the laminate>
The laminate that constitutes the battery housing of the present invention has a resin layer and a support layer, and the support layer may be on one side of the resin layer, but as shown in FIG. It may have a support layer 11 on it. In this aspect, since the support layer 11 is in contact with the flame, the support layer 11 that has come into contact with the flame no longer functions as a support layer, but the other support layer 11 functions as a support layer, so the above-mentioned It exhibits flame-retardant properties through a similar mechanism of action.
Further, in this embodiment, since the support layers 11 are provided on both sides of the resin layer 12, warping does not occur in the laminate, which is preferable.

Furthermore, as shown in FIG. 5, the laminate 10 constituting the battery housing of the present invention may have two resin layers 12 with the support layer 11 sandwiched therebetween. In the case of this embodiment, the effects of the present invention are achieved even if either the upper surface or the lower surface is in contact with the flame, and there is no need to check the front and back sides of the laminate when manufacturing the battery housing.

[Laminated body]
Hereinafter, the laminate that constitutes the battery housing of the present invention will be explained in detail.
In the present invention, the laminate 10 has a resin layer 12 and a support layer 11 laminated on at least one surface of the resin layer 12, as shown in a schematic diagram in FIG. The resin layer 12 has a flame retardant 13, and preferably has fibers 14, as will be described in detail later.
The thickness of the resin layer is preferably at least twice the thickness of the support layer. When the thickness of the resin layer is at least twice the thickness of the support layer, sufficient flameproofing properties can be imparted to the laminate. From the above viewpoint, the thickness of the resin layer is more preferably 2.5 times or more than the thickness of the support layer, even more preferably 5 times or more, even more preferably 8 times or more, and even more preferably 10 times the thickness of the support layer. It is particularly preferable that it is above.
On the other hand, the upper limit of the thickness of the resin layer relative to the thickness of the support layer is not particularly limited and is appropriately determined depending on the application, but it is usually preferably 50 times or less, more preferably 45 times or less, and 30 times or less. It is even more preferably at most 20 times, even more preferably at most 20 times, even more preferably at most 15 times.

The thickness of the resin layer is not particularly limited as long as it satisfies the above ratio, but it is preferably 0.5 mm or more in order to obtain sufficient flameproofing properties. On the other hand, the thickness of the resin layer has a preferable thickness depending on the application, but it is usually preferably 50 mm or less. From the above viewpoint, the thickness of the resin layer is more preferably in the range of 1 to 25 mm, even more preferably in the range of 1.3 to 15 mm, and even more preferably in the range of 1.5 to 10 mm. Preferably, the range is particularly preferably from 1.7 to 5 mm.

It is also preferable that the thickness of the resin layer is 70% or more of the total thickness of the resin layer and the support layer, from the viewpoint of imparting even more excellent flameproofing properties to the battery housing. From the same viewpoint, the thickness of the resin layer is more preferably 75% or more, even more preferably 80% or more, particularly 85% or more of the total thickness of the resin layer and the support layer. preferable.
On the other hand, the upper limit of the thickness of the resin layer is not particularly limited and is appropriately determined depending on the application, but it is usually preferably 98% or less, more preferably 95% or less.

In the present invention, the laminate preferably satisfies at least one of the following conditions (a1) and (b1).
Condition (a1): The minimum value of the flexural modulus measured in accordance with JIS K7171 (ISO 178) is 1000 MPa or more;
Condition (b1): The minimum value of bending strength measured in accordance with JIS K7171 (ISO 178) is 10 MPa or more. The above laminate preferably satisfies either of the above conditions (a1) or (b1), It is more preferable that both requirements (a1) and (b1) are satisfied.

When the laminate satisfies at least one of the above conditions (a1) and (b1), sufficient flameproofing properties can be imparted to the laminate. Note that the minimum value of the bending elastic modulus measured in accordance with JIS K7171 (ISO 178) refers to the smallest value among the bending elastic moduli measured in any direction parallel to the plane of the laminate. Generally, the numerical value of the flexural modulus differs depending on the direction in which the flexural modulus is measured with respect to the plane of the laminate. Typically, the value of the flexural modulus measured in the flow direction of the resin layer constituting the laminate is often the largest, and the value of the flexural modulus measured in the direction perpendicular to the flow direction is often the smallest. many. Furthermore, the numerical value of the flexural modulus may vary depending on the direction in which force is applied to the laminate, which is a test piece, during measurement. For example, there are cases in which force is applied to the resin layer side of the laminate and forces are applied to the support layer side. In this case, the bending modulus of elasticity when force is applied from either direction is , the smallest value is taken as the minimum value of the flexural modulus.
The bending strength is also the same as the bending modulus, and among the bending strengths measured in any direction parallel to the plane of the laminate, the smallest value is taken as the minimum value of the bending strength.

In the present invention, the laminate preferably satisfies the above condition (a1). That is, it is preferable that the minimum value of the bending elastic modulus measured in accordance with JIS K7171 (ISO 178) is 1000 MPa or more. In this case, sufficient flameproofing properties can be imparted to the laminate. From the above viewpoint, the minimum value of the bending elastic modulus is more preferably 2000 MPa or more, further preferably 2500 MPa or more, and particularly preferably 3000 MPa or more (condition (a2)).
In the above laminate, the average value of the flexural modulus measured in the flow direction of the resin and the flexural modulus measured in the direction perpendicular to the flow direction is 3000 MPa or more (condition (a3)). It is also preferable from the viewpoint of improving the flameproofing properties of the laminate. In particular, it is preferable that the condition (a1) and the condition (a3) are satisfied. The average value of the bending elastic modulus in the flow direction and the bending elastic modulus in a direction orthogonal to the flow direction is more preferably 4000 MPa or more, and even more preferably 5000 MPa or more. On the other hand, the upper limit is usually 10 GPa or less. Note that the flow direction of the resin can be confirmed by observing the cross section of the laminate.

In the present invention, it is also preferable that the laminate satisfies the above condition (b1). That is, it is preferable that the minimum value of the bending strength measured according to JIS K7171 (ISO 178) is 10 MPa or more. In this case, sufficient flameproofing properties can be imparted to the laminate. From the above viewpoint, the minimum value of the bending elastic modulus is more preferably 20 MPa or more, further preferably 2500 MPa or more, and particularly preferably 30 MPa or more (condition (b2)).
In the present invention, the laminate has an average value of bending strength measured in the flow direction of the resin and bending strength measured in a direction perpendicular to the flow direction of 30 MPa or more (condition (b3)). This is also preferable from the viewpoint of improving the flameproofing properties of the laminate.In particular, it is preferable that the above-mentioned condition (b1) is satisfied and condition (b3) is also satisfied.The bending elastic modulus in the flow direction and the direction perpendicular to the flow direction The average value of the flexural modulus of elasticity is more preferably 50 MPa or more, and even more preferably 80 MPa or more.On the other hand, the upper limit is usually 1000 MPa or less.As mentioned above, the flow direction of the resin is determined by observing the cross section of the laminate. It can be confirmed.

In the present invention, when a force is applied to one surface of the laminate, the average value of the bending strength measured in the flow direction of the resin and the bending strength measured in the direction perpendicular to the flow direction is , when a force is applied to the surface opposite to that surface, the ratio of the average value of the bending strength value measured in the flow direction of the resin and the bending strength value measured in the direction perpendicular to the flow direction is 105% The above is preferable from the viewpoint of improving the flameproofing properties of the laminate. The above ratio is more preferably 110% or more, and usually 300% or less.

The above-mentioned laminate only needs to have a resin layer and a support layer laminated on at least one surface of the resin layer, and does not exclude an embodiment in which an adhesive layer is provided between the resin layer and the support layer. From the viewpoint of improving flameproofing properties, the binding property between the resin layer and the support layer is important, and it is preferable that the resin layer and the support layer are directly bound without intervening another layer. From the same viewpoint, it is more preferable that in the laminate, at least a portion of the resin composition contained in the resin layer is melted and bonded directly to the support layer. In the laminate, it is particularly preferable that at least a portion of the resin composition contained in the resin layer is melted and impregnated into the support layer, thereby directly bonding the resin composition.

<Resin layer>
In the laminate forming the battery housing of the present invention, the resin layer is made of a resin composition containing (A) a thermoplastic resin and (B) a flame retardant. Hereinafter, the (A) thermoplastic resin and (B) flame retardant that constitute the resin composition will be explained in detail.

<<(A) Thermoplastic resin>>
In the present invention, the thermoplastic resin constituting the resin composition is not particularly limited, and includes polyolefin resin, polycarbonate resin, polyester resin, acrylonitrile styrene resin, ABS resin, polyamide resin, modified polyphenylene oxide, polyvinyl chloride, Examples include polystyrene, polyvinyl acetate, polyurethane, and the like. Note that these may be used alone or in combination of two or more. For example, the thermoplastic resin (A) may be a composite resin of two or more of the above thermoplastic resins.
Among these, polyolefin resins are preferred from the viewpoint of resin physical properties, versatility, cost, etc., and polypropylene resins are particularly preferred.

The polyolefin resin is not particularly limited, and examples include the resins described below. There are no particular limitations on the polyester resin, and examples thereof include polybutylene terephthalate. The polyamide resin is not particularly limited, and examples thereof include nylon 66 and nylon 6.
Among these, in the present invention, it is particularly preferable that the thermoplastic resin (A) contains at least a polyolefin resin. In the present invention, the term "polyolefin resin" refers to a resin in which the ratio of olefin units or cycloolefin units to 100 mol% of all the structural units constituting the resin is 90 mol% or more.
The ratio of olefin units or cycloolefin units to 100 mol% of all structural units constituting the polyolefin resin is preferably 95 mol% or more, particularly preferably 98 mol% or more.

Examples of polyolefin resins include α-olefins such as polyethylene, polypropylene, polybutene, poly(3-methyl-1-butene), poly(3-methyl-1-pentene), and poly(4-methyl-1-pentene). Polymer; α- 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, etc. Olefin copolymers; examples include 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, the α-olefin having 4 or more carbon atoms includes butene, 3-methyl-1-butene, 3-methyl-1-pentene, 4 -Methyl-1-pentene and the like.
Among these, in the laminate constituting the battery housing of the present invention, it is particularly preferable that the thermoplastic resin (A) is a polypropylene resin. The polypropylene resin will be detailed later.
In addition, the said polyolefin resin may be used individually by 1 type, and may use 2 or more types together.

(Melt flow rate (MFR))
The melt flow rate (hereinafter sometimes abbreviated as MFR) (230° C., 2.16 kg load) of the thermoplastic resin (A) used in the present invention is preferably 5 to 500 g/10 minutes. When the MFR is 5 g/10 minutes or more, good fluidity is obtained when producing a molded article by injection molding, for example, and processability becomes good. On the other hand, if it is 500 g/10 minutes or less, the strength of the molded article will be sufficient. From the above viewpoint, MFR is preferably in the range of 10 to 300 g/10 minutes, more preferably 20 to 200 g/10 minutes, and still more preferably 25 to 100 g/10 minutes.
The MFR of the thermoplastic resin (A) can be adjusted by, for example, controlling the hydrogen concentration during polymerization. Furthermore, MFR is a value measured in accordance with JIS K7210-1.

((A) Thermoplastic resin content)
In the present invention, the content of the thermoplastic resin (A) in the resin composition 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, molding processability is particularly good, and molding of a molded article becomes easy. On the other hand, when the content is 80% by mass or less, sufficient amounts of flame retardants, dispersants, fibers, etc., which will be described later, can be contained, and good flameproofing properties can be obtained. From the above viewpoint, the content of the thermoplastic resin in the resin composition is preferably 35 to 70% by mass, more preferably 40 to 60% by mass. In addition, when the thermoplastic resin (A) is the above-mentioned suitable polypropylene resin, the suitable content is the same.

<<<(A-1) Polypropylene resin>>>
In the present invention, the thermoplastic resin (A) constituting the resin composition preferably includes a polypropylene resin, as described above. Examples of the polypropylene resin include propylene homopolymers and propylene-α-olefin copolymers. The propylene-α-olefin copolymer may be either a random copolymer or a block copolymer.

(α-olefin)
Examples of the α-olefin constituting the copolymer include ethylene, 1-butene, 2-methyl-1-propene, 1-pentene, 2-methyl-1-butene, 3-methyl-1-butene, 1 -hexene, 2-ethyl-1-butene, 2,3-dimethyl-1-butene, 2-methyl-1-pentene, 3-methyl-1-pentene, 4-methyl-1-pentene, 3,3-dimethyl Examples include -1-butene, 1-heptene, methyl-1-hexene, dimethyl-1-pentene, ethyl-1-pentene, trimethyl-1-butene, and 1-octene. One type of these may be used to copolymerize with propylene, or two or more types may be used to copolymerize with propylene. Among them, from the viewpoint of improving the impact strength of the laminate, ethylene or 1-butene is preferable because of its large effect, and ethylene is most preferable.

(Propylene-ethylene random copolymer)
In the case of a random copolymer of propylene and ethylene, the propylene unit is preferably 90 to 99.5% by mass, more preferably 92 to 99% by mass, and the ethylene unit is preferably 0.5 to 10% by mass, even more preferably 1 ~8% by mass. When the ethylene unit is at least the above lower limit, sufficient impact strength of the laminate is obtained, and when it is at most the above upper limit, sufficient rigidity is maintained. That is, it is possible to obtain a laminate having excellent heat resistance and flameproofing properties, as well as excellent mechanical properties.
The content of propylene units and ethylene units in the random copolymer of propylene and ethylene can be adjusted by controlling the composition ratio of propylene and ethylene during polymerization of the random copolymer of propylene and ethylene.
In addition, the propylene content of the random copolymer of propylene and ethylene is a value measured using a cross fractionator, FT-IR, etc., and the measurement conditions are described, for example, in JP-A No. 2008-189893. You can use the method provided.

<<<Modified polyolefin resin>>>
In the present invention, the resin composition may further contain a modified polyolefin resin in addition to the polypropylene resin. Specific examples of modified polyolefin resins include acid-modified polyolefin resins and hydroxy-modified polyolefin resins, and each of these may be used alone or both may be used in combination.
The types of acid-modified polyolefin resin and hydroxy-modified polyolefin resin used as the modified polyolefin resin are not particularly limited, and conventionally known ones may be used.

(Acid-modified polyolefin resin)
Examples of acid-modified polyolefin resins include polyethylene, polypropylene, ethylene-α-olefin copolymer, ethylene-α-olefin-nonconjugated diene compound copolymer (EPDM, etc.), ethylene-aromatic monovinyl compound-conjugated diene, etc. Examples include chemically modified polyolefins such as compound copolymerized elastomers by graft copolymerizing them with unsaturated carboxylic acids such as maleic acid or maleic anhydride.
This graft copolymerization is carried out, for example, by reacting the polyolefin with an unsaturated carboxylic acid in a suitable solvent using a radical generator such as benzoyl peroxide. Moreover, the component of unsaturated carboxylic acid or its derivative can also be introduced into the polymer chain by random or block copolymerization with a monomer for polyolefin.

Examples of unsaturated carboxylic acids used for modification include carboxyl groups such as maleic acid, fumaric acid, itaconic acid, acrylic acid, and methacrylic acid, and functional groups such as hydroxyl groups and amino groups as necessary. Examples include compounds having an introduced polymerizable double bond.
Derivatives of unsaturated carboxylic acids include their acid anhydrides, esters, amides, imides, metal salts, etc. Specific examples include maleic anhydride, itaconic anhydride, methyl acrylate, and ethyl acrylate. , butyl acrylate, methyl methacrylate, and the like. Among these, maleic anhydride is preferred.

Preferred acid-modified polyolefin resins include those modified by graft polymerizing maleic anhydride to olefin polymers whose main polymer constituent units are ethylene and/or propylene, and olefins whose main constituent units are ethylene and/or propylene. Examples include those modified by copolymerizing and maleic anhydride. Specific examples include a combination of polyethylene/maleic anhydride grafted ethylene/butene-1 copolymer, or a combination of polypropylene/maleic anhydride grafted polypropylene.

(Hydroxy-modified polyolefin resin)
The hydroxy-modified polyolefin resin is a modified polyolefin resin containing a hydroxyl group. The hydroxy-modified polyolefin resin may have a hydroxyl group at a suitable site, for example, at the end of the main chain or at a side chain.
Examples of the olefin resin constituting the hydroxy-modified polyolefin resin include homopolymers or copolymers of α-olefins such as ethylene, propylene, butene, 4-methylpentene-1, hexene, octene, nonene, decene, and dodecene; Examples include copolymers of the α-olefin and copolymerizable monomers.
Preferred hydroxy-modified polyolefin resins include, for example, low-density, medium-density, or high-density polyethylene, linear low-density polyethylene, ultra-high molecular weight polyethylene, ethylene-(meth)acrylate copolymer, and ethylene-vinyl acetate copolymer. Hydroxy-modified polyethylene resins such as polymers, e.g. polypropylene homopolymers such as isotactic polypropylene, random copolymers of propylene and α-olefins (e.g. ethylene, butene, hexane, etc.), propylene-α-olefin blocks Examples include copolymers and hydroxy-modified polypropylene resins such as hydroxy-modified poly(4-methylpentene-1).

<<(B) Flame retardant>>
In the present invention, the resin composition contains (B) a flame retardant. (B) The flame retardant is not particularly limited, and examples thereof include phosphorus-based flame retardants, bromine-based flame retardants, antimony-based flame retardants, and the like. Among these, phosphorus-based flame retardants are preferred from the viewpoint of improving flameproofing properties. Further, in the classification based on the mechanism of action of the flame retardant, it is preferable that the flame retardant (B) is an intomescent type flame retardant from the viewpoint of improving the flame retardant property.

(phosphorus flame retardant)
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 exhibits a flame retardant effect by forming a char (charred film) during combustion of the resin composition.
The phosphorus-based flame retardant may be any known one, such as (poly)phosphates, (poly)phosphate esters, and the like. Here, "(poly)phosphate" refers to phosphate or polyphosphate, and "(poly)phosphate" refers to phosphate or polyphosphate.
Note that the phosphorus flame retardant is preferably solid at 80°C.

As the phosphorus-based flame retardant, (poly)phosphates are preferred from the viewpoint of flame retardancy.
Examples of (poly)phosphates include ammonium polyphosphate, melamine polyphosphate, piperazine polyphosphate, piperazine orthophosphate, melamine pyrophosphate, piperazine pyrophosphate, melamine orthophosphate, calcium phosphate, phosphoric acid Examples include magnesium.
Furthermore, in the above examples, compounds in which melamine or piperazine is replaced with other nitrogen compounds can also be used. Other nitrogen compounds include, for example, 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'-tetraethylethylenediamine, 1,2-propanediamine, 1,3-propanediamine, tetramethylenediamine , pentamethylene diamine, hexamethylene diamine, 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, ammeline, benzguanamine, acetate Guanamine, phthalodiguanamine, melamine cyanurate, butylene diguanamine, norbornene diguanamine, methylene diguanamine, ethylene dimelamine, trimethylene dimelamine, tetramethylene dimelamine, hexamethylene dimelamine, 1,3-hexylene diguanamine Examples include melamine. These (poly)phosphates may be used alone or in combination of two or more.

Among the above-mentioned phosphorus-based flame retardants, a salt of (poly)phosphoric acid and a nitrogen compound (hereinafter also referred to as "compound (B1)") is preferable. Compound (B1) is an intomescent flame retardant. Intumescent flame retardants are flame retardants that suppress the combustion of materials by forming a surface intumescent layer (Intumescent) that prevents radiant heat from the combustion source and the diffusion of combustion gas and smoke from the burning material to the outside. be. By forming the surface expansion layer, diffusion of decomposition products and heat transfer are suppressed, and excellent flame retardancy is exhibited.
Examples of the nitrogen compound in compound (B1) include ammonia, melamine, piperazine, and the other nitrogen compounds mentioned above. Specific examples 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. Moreover, zinc oxide can also be contained as a flame retardant aid. This case is preferable because the flame retardant performance is further improved.

Commercially available phosphorus flame retardants include ADEKA STAB FP-2100J, FP-2200, and FP-2500S (manufactured by ADEKA Corporation).

(brominated flame retardant)
Examples of brominated flame retardants include decabromodiphenyl ether, tetrabromobisphenol A, tetrabromobisphenol S, 1,2-bis(2',3',4',5',6'-pentabromophenyl)ethane, 1,2-bis(2,4,6-tribromophenoxy)ethane, 2,4,6-tris(2,4,6-tribromophenoxy)-1,3,5-triazine, 2,6-dibromo Phenol, 2,4-dibromophenol, brominated polystyrene, ethylene bistetrabromophthalimide, hexabromocyclododecane, hexabromobenzene, pentabromobenzyl acrylate, 2,2-bis[4'(2'',3''- dibromopropoxy)-3',5'-dibromophenyl]-propane, bis[3,5-dibromo-4-(2,3-dibromopropoxy)phenyl]sulfone, tris(2,3-dibromopropyl)isocyanurate, etc. can be mentioned.

(antimony-based flame retardant)
Examples of antimony-based flame retardants include antimony trioxide, antimony tetroxide, antimony pentoxide, sodium pyroantimonate, antimony trichloride, antimony trisulfide, antimony oxychloride, antimony dichloride perchloropentane, and potassium antimonate. Antimony trioxide and antimony pentoxide are particularly preferred.

Among the above-mentioned flame retardants, phosphorus-based flame retardants are preferred because they have no bioresistance and have excellent flame retardancy, and non-halogen-based flame retardants are preferred from the viewpoint of environmental friendliness. Furthermore, intumescent flame retardants are preferred from the viewpoint of improving the flame retardant properties of the resulting laminate.
In addition, the said flame retardant can be used individually by 1 type, or can also use 2 or more types together.

((B) Content of flame retardant)
In the present invention, the content of the flame retardant in the resin composition is not particularly limited, but is preferably in the range of 1 to 40% by mass. When the content is 1% by mass or more, good flame retardancy can be imparted to the laminate, and good flameproofing properties can be obtained. On the other hand, when the flame retardant content is 40% by mass or less, the thermoplastic resin can be contained at a sufficient content ratio, so moldability becomes better. From the above viewpoints, in the present invention, the content of the flame retardant in the resin composition is more preferably in the range of 1 to 35% by mass, even more preferably in the range of 3 to 30% by mass, and particularly 5 to 25% by mass. preferable.

<<(C) Fiber>>
In the present invention, the resin composition preferably contains (C) fibers in addition to the components (A) and (B). (C) Fibers may be organic or inorganic fibers, but inorganic fibers are preferred from the viewpoint of heat resistance, such as glass fibers, rock wool, basalt fibers, alumina fibers, silica-alumina fibers, potassium titanate fibers, and silicate fibers. Ceramic fibers such as acid calcium (wollastonite) fibers, alkaline earth silicate fibers (biosoluble), silica fibers, metal oxide fibers, carbon fibers, stainless steel fibers, metal fibers such as tungsten fibers, and the like. These inorganic fibers may be used alone or in combination of two or more.
Furthermore, among these inorganic fibers, at least one selected from the group consisting of glass fibers, ceramic fibers such as alumina fibers, metal oxide fibers, and carbon fibers can improve heat resistance and flameproofing properties. preferable.

The fiber (C) used in the present invention preferably has an average fiber diameter of 3 to 25 μm. Further, the average fiber length is preferably in the range of 0.05 to 100 mm, more preferably in the range of 0.5 to 50 mm, even more preferably in the range of 1 to 25 mm, and even more preferably in the range of 2 to 15 mm. It is particularly preferable that the range is within the range. When the average fiber length is within the above range, a laminate having a resin layer containing the resin composition has better mechanical strength (flexural strength, etc.) and excellent heat resistance. Although not bound by a particular theory, it is believed that when the average fiber length is within the above range, the above-mentioned (C) fibers tend to be oriented in the resin layer, so that the above advantages can be obtained. Within the above range, the longer the average fiber length, the better the mechanical strength and heat resistance tend to be.
When there are multiple types of fibers, the average fiber diameter and average fiber length of at least one type of fiber may be within the above ranges.

The average fiber length of the fibers (C) contained in the resin composition may vary depending on the method of manufacturing the laminate. For example, when injection molding, which will be described later, is used, the resin composition is heated and melted, so the fibers tend to break and the average fiber length tends to become short. The above average fiber length means the average fiber length in the resin composition, and is the fiber length before being subjected to heat history. Therefore, the average fiber length of the fibers in the laminate produced by a method such as injection molding is preferably in the range of 0.05 to 50 mm, more preferably in the range of 0.25 to 25 mm, and It is more preferably in the range of .5 to 15 mm, particularly preferably in the range of 1 to 10 mm.
On the other hand, when the laminate is manufactured by a lamination method, the average fiber length of the (C) fibers in the resin composition and the average fiber length of the (C) fibers in the laminate do not change.
Note that the fiber diameter can be measured using an optical microscope or the like, and the average fiber diameter can be obtained, for example, by randomly measuring the fiber diameters of 10 fibers and calculating the average value. In addition, the fiber length can be measured using a ruler, a caliper, etc. from an image enlarged with a microscope, etc., if necessary.The average fiber length can be measured, for example, by randomly measuring the fiber length of 10 fibers, and measuring the average fiber length. It can be obtained by calculating the value.

In the present invention, when the resin composition contains fibers, the content of fibers in the resin composition is preferably 3 to 60% by mass. When the fiber content is 3% by mass or more, the strength, rigidity, and impact resistance of the laminate can be ensured. On the other hand, if the content is 60% by mass or less, the laminate can be easily manufactured and processed. Further, since the fiber content is 60% by mass or less, the specific gravity is small, and there is an advantage that the weight reduction effect as a metal substitute is large.
From the above viewpoint, in the present invention, the content of fibers in the resin composition is more preferably 10 to 50% by mass, even more preferably 20 to 45% by mass, and even more preferably 25 to 40% by mass. Even more preferred.

(glass fiber)
Glass fiber is one of the (C) fibers suitable for the laminate that constitutes the battery housing of the present invention. The glass fibers may be, for example, long fibers with an average fiber length of 30 mm or more, or fibers with a short average fiber length (chopped strands).
More specifically, the average fiber length is preferably in the range of 0.05 to 100 mm. When the average fiber length is within the above range, the strength and impact resistance of the laminate will be good. From the above viewpoint, the range is more preferably 0.5 to 50 mm, even more preferably 1 to 25 mm, and particularly preferably 2 to 15 mm. In the case of glass fibers as (C) fibers in a laminate produced by a method such as injection molding, the average fiber length is preferably in the range of 0.05 to 50 mm, and preferably in the range of 0.25 to 25 mm. More preferably, the range is 0.5 to 15 mm, and particularly preferably 1 to 10 mm.
Note that there is no particular upper limit to the average fiber length of glass fibers. For example, when using pellets manufactured by the pultrusion method using glass fibers, the length of the pellets is longer than that of the glass fibers. Since it is long, the maximum length is about 20 mm. In addition, in the swirl mat system using long glass fibers, the maximum fiber length is the length of the glass fibers in the roving used for manufacturing, so it is about 17,000 m (17 km), but depending on the size of the laminate. , when cut, the cut length is the maximum fiber length.

Further, the average fiber diameter of the glass fibers is preferably in the range of 9 to 25 μm. When the average fiber diameter is 9 μm or more, the laminate has sufficient rigidity and impact resistance, while when the average fiber diameter is 25 μm or less, the laminate has good strength. From the above viewpoint, it is more preferable that the average fiber diameter of the glass fibers is in the range of 10 to 15 μm.
Note that the average fiber diameter and average fiber length of the glass fibers can be measured by the above method.

The material of the glass fiber used in the present invention is not particularly limited, and may be any of alkali-free glass, low-alkali glass, and alkali-containing glass. can be used.

(Alumina fiber)
Alumina fiber is one of the (C) fibers suitable for the laminate that constitutes the battery housing of the present invention. Alumina fibers are usually fibers made of alumina and silica, and in the above laminate, the alumina/silica composition ratio (mass ratio) of the alumina fibers is a mullite composition of 65/35 to 98/2 or a high alumina composition. It is preferably within the range referred to above, more preferably from 70/30 to 95/5, particularly preferably from 70/30 to 74/26.

The average fiber diameter of the alumina fibers is preferably in the range of 3 to 25 μm, and preferably does not substantially contain fibers with a fiber diameter of 3 μm or less. Here, "substantially not containing fibers with a fiber diameter of 3 μm or less" means that fibers with a fiber diameter of less than 3 μm account for 0.1% by mass or less of the total fiber mass. When the average fiber diameter is 3 μm or more, the amount of dust floating in the air is reduced. On the other hand, it is preferable that the thickness is 25 μm or less in terms of the rigidity and impact resistance of the laminate.
The average fiber length of the alumina fibers is preferably in the range of 0.05 to 100 mm. When the average fiber length is within the above range, the strength and impact resistance of the laminate will be good. From the above viewpoint, the range is more preferably 0.5 to 50 mm, even more preferably 1 to 25 mm, and particularly preferably 2 to 15 mm. In the case of alumina fibers as the (C) fibers in a laminate produced by a method such as injection molding, the average fiber length is preferably in the range of 0.05 to 50 mm, and preferably in the range of 0.25 to 25 mm. More preferably, the range is 0.5 to 15 mm, and particularly preferably 1 to 10 mm.

(Carbon fiber)
Carbon fibers also have the same preferred ranges as glass fibers in terms of average fiber diameter and average fiber length.
Note that carbon fiber may be contained in order to provide electromagnetic wave shielding properties.

<<(D) Dispersant>>
In the present invention, the resin composition preferably contains (D) a dispersant. (D) The dispersant is not particularly limited as long as it can disperse the (B) flame retardant in the (A) thermoplastic resin. Dispersants can be suitably used. Preferably, one that can disperse the flame retardant (B) in the polypropylene resin (A-1) can be used. As the polymer dispersant, a polymer dispersant having a functional group is preferable, and from the viewpoint of dispersion stability, a carboxyl group, a phosphoric acid group, a sulfonic acid group, a primary, secondary or tertiary amino group, a quaternary ammonium base, Preferred are polymeric dispersants having functional groups such as groups derived from nitrogen-containing heterocycles such as pyridine, pyrimidine, and pyrazine.
In the present invention, a polymeric dispersant having a carboxyl group is preferred, and in particular, when a phosphorus-based flame retardant suitable as a flame retardant is used, a copolymer of an α-olefin and an unsaturated carboxylic acid is preferred. By using the dispersant, the dispersibility of the phosphorus-based flame retardant can be improved, and the content of the flame retardant can be reduced.

(Copolymer of α-olefin and unsaturated carboxylic acid)
In the present invention, the α-olefin unit and the unsaturated carboxylic acid unit in the above-mentioned “copolymer of α-olefin and unsaturated carboxylic acid” (hereinafter referred to as “copolymer (D1)”) are: It is preferable that the proportion of α-olefin units out of the total 100 mol% is 20 mol% or more and 80 mol% or less.
In the copolymer (D1), the ratio of α-olefin units to the total amount of α-olefin units and unsaturated carboxylic acid units is more preferably 30 mol% or more, while it is preferably 70 mol% or less. More preferred. If the proportion of α-olefin is above the lower limit, the compatibility with (A) thermoplastic resin such as polyolefin resin will be better, and if it is below the upper limit, it will be more compatible with (B) flame retardant. The compatibility of the two becomes better.

In the copolymer (D1), the α-olefin is preferably an α-olefin having 5 or more carbon atoms, more preferably an α-olefin having 10 or more and 80 or less carbon atoms. If the α-olefin has 5 or more carbon atoms, its compatibility with the thermoplastic resin (A) tends to be better, and if it has 80 or less, it is advantageous in terms of raw material cost. From the above viewpoint, the number of carbon atoms in the α-olefin is more preferably 12 or more and 70 or less, even more preferably 15 or more and 65 or less, and particularly preferably 18 or more and 60 or less.

In the copolymer (D1), examples of the unsaturated carboxylic acid include (meth)acrylic acid, maleic acid, methylmaleic acid, fumaric acid, methylfumaric acid, tetrahydrophthalic acid, itaconic acid, citraconic acid, and crotonic acid. , isocrotonic acid, glutaconic acid, norbornan-5-ene-2,3-dicarboxylic acid, and esters, anhydrides, and imides of these unsaturated carboxylic acids. Note that "(meth)acrylic acid" refers to acrylic acid or methacrylic acid.
Specific examples of esters, anhydrides or imides of unsaturated carboxylic acids include methyl (meth)acrylate, ethyl (meth)acrylate, butyl (meth)acrylate, 2-ethylhexyl (meth)acrylate, ( (Meth)acrylic acid esters such as glycidyl meth)acrylate; dicarboxylic acid anhydrides such as maleic anhydride, itaconic anhydride, citraconic anhydride, 5-norbornene-2,3-dicarboxylic anhydride; maleimide, N-ethyl Examples include maleimide compounds such as maleimide and N-phenylmaleimide. 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 these, 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.

The weight average molecular weight of the copolymer (D1) is preferably 2,000 or more, more preferably 3,000 or more, while it is preferably 50,000 or less, and more preferably 30,000 or less. If the weight average molecular weight of the copolymer (D1) is within the above range, the flame retardant (B) will have better dispersibility.
The weight average molecular weight of the copolymer (D1) is a standard polystyrene equivalent value measured by gel permeation chromatography after dissolving the copolymer (D1) in tetrahydrofuran (THF).

Commercially available products of the copolymer (D1) include Recolb CE2 (manufactured by Clariant Japan Co., Ltd.) and Diacarna 30M (manufactured by Mitsubishi Chemical Co., Ltd.).

In the present invention, the content of the dispersant (D) relative to 100 parts by mass of the flame retardant (B) in the resin composition is preferably in the range of 0.1 to 25 parts by mass, and preferably in the range of 1 to 10 parts by mass. is more preferable, and the range of 2 to 5 parts by mass is even more preferable.
When the content of the dispersant (D) is at least the above lower limit, the flame retardant (B) is sufficiently dispersed, making it easy to obtain good flameproofing properties. On the other hand, when it is below the above upper limit, the mechanical properties etc. of the laminate are maintained.

The ratio of the dispersant (D) to a total of 100 parts by mass of the thermoplastic resin (A) and the flame retardant (B) is preferably 0.01 parts by mass or more, more preferably 0.05 parts by mass or more. The amount is preferably 0.1 part by mass or more, and more preferably 0.1 part by mass or more. On the other hand, the amount is preferably 10 parts by mass or less, more preferably 5.0 parts by mass or less, even more preferably 2.0 parts by mass or less, more preferably 1.5 parts by mass or less, and 1.0 parts by mass. It is more preferable that it is the following. If the ratio of the dispersant (D) is equal to or higher than the lower limit, the flame retardant (B) will be better dispersed, and the flame retardant properties, physical properties, and appearance of the laminate will be better. If the ratio of the dispersant (D) is below the upper limit, the influence of the dispersant (D) on the flameproofing properties of the laminate can be further suppressed.

For (C) fibers, the ratio of (D) dispersant to 100 parts by mass of (C) fibers is preferably 0.01 parts by mass or more, more preferably 0.05 parts by mass or more. , more preferably 0.1 parts by mass or more, even more preferably 0.5 parts by mass or more, particularly preferably 1.0 parts by mass or more. On the other hand, it is preferably 10 parts by mass or less, more preferably 5.0 parts by mass or less, and even more preferably 2.0 parts by mass or less. (D) If the proportion of the dispersant is at least the lower limit, the resulting laminate will have better flame-retardant properties, physical properties, and appearance. If the ratio of the dispersant (D) is below the upper limit, the influence of the dispersant (D) on the flameproofing properties of the laminate can be further suppressed.

<<Optional addition ingredients>>
In the present invention, in addition to the above-mentioned components, the resin composition may contain any optional ingredients for the purpose of imparting other effects such as further improving the effects of the invention, within a range that does not significantly impair the effects of the present invention. Additional ingredients can be blended.
Specifically, colorants, light stabilizers, ultraviolet absorbers, nucleating agents such as sorbitol, antioxidants, antistatic agents, neutralizing agents such as inorganic compounds, antibacterial and antifungal agents such as thiazole, Flame retardants/flame retardant aids such as halogen compounds and lignophenol, plasticizers, dispersants such as organic metal salts, lubricants such as fatty acid amide, metal deactivators such as nitrogen compounds, polyolefins other than the polypropylene resins mentioned above. Examples include resins, thermoplastic resins such as polyamide resins and polyester resins, and elastomers (rubber components) such as olefin elastomers and styrene elastomers.
Two or more of these optionally added components may be used in combination.

As a coloring agent, for example, an inorganic or organic pigment can be used to improve the colored appearance, appearance, texture, commercial value, weather resistance, etc. of a resin composition and a laminate having a resin layer made of the resin composition. It is effective in imparting and improving durability.
As specific examples, inorganic pigments include carbon black such as furnace carbon and Ketjen carbon; titanium oxide; iron oxide (red iron oxide, etc.); chromic acid (yellow etc.); molybdic acid; sulfurized selenide; ferrocyanide, etc. Examples of organic pigments include poorly soluble azo lake, soluble azo lake, insoluble azo chelate; condensable azo chelate; azo pigments such as other azo chelates; phthalocyanine pigments such as phthalocyanine blue and phthalocyanine green; anthraquinone, perinone, perylene, Thread-based pigments such as thioindigo; dye lakes; quinacridone-based; dioxazine-based; and isoindolinone-based. In addition, aluminum flakes and pearl pigments can be added to give a metallic or pearlescent tone. Moreover, a dye can also be contained.

As light stabilizers and ultraviolet absorbers, for example, hindered amine compounds, benzotriazole-based, benzophenone-based, and salicylate-based agents are used to improve the weather resistance and durability of resin compositions and laminates having resin layers made of the resin compositions. It is effective for imparting and improving weatherability and discoloration resistance.
As a specific example, a condensate of dimethyl succinate and 1-(2-hydroxyethyl)-4-hydroxy-2,2,6,6-tetramethylpiperidine; poly[[6-(1, 1,3,3-tetramethylbutyl)imino-1,3,5-triazine-2,4-diyl][(2,2,6,6-tetramethyl-4-piperidyl)imino]hexamethylene[(2 ,2,6,6-tetramethyl-4-piperidyl)imino]];tetrakis(2,2,6,6-tetramethyl-4-piperidyl)1,2,3,4-butanetetracarboxylate;tetrakis( 1,2,2,6,6-pentamethyl-4-piperidyl) 1,2,3,4-butanetetracarboxylate; bis(1,2,2,6,6-pentamethyl-4-piperidyl) sebacate; bis Examples include -2,2,6,6-tetramethyl-4-piperidyl sebacate, and examples of benzotriazoles include 2-(2'-hydroxy-3',5'-di-t-butylphenyl)- 5-chlorobenzotriazole; 2-(2'-hydroxy-3'-t-butyl-5'-methylphenyl)-5-chlorobenzotriazole, etc.; examples of benzophenone include 2-hydroxy-4-methoxy; Examples of salicylates include benzophenone; 2-hydroxy-4-n-octoxybenzophenone; examples of salicylates include 4-t-butylphenyl salicylate; 2,4-di-t-butylphenyl 3',5'-di-t -butyl-4'-hydroxybenzoate and the like.
Here, the method of using the above-mentioned light stabilizer and ultraviolet absorber in combination is preferable because it has a large effect of improving weather resistance, durability, resistance to weather discoloration, and the like.

As antioxidants, for example, phenol-based, phosphorus-based, and sulfur-based antioxidants are used to impart and improve heat resistance stability, processing stability, heat aging resistance, etc. of polypropylene resin compositions and molded products thereof. It is effective for
In addition, as an antistatic agent, for example, a nonionic or cationic antistatic agent can be used to impart and improve the antistatic properties of the above resin composition and a laminate having a resin layer composed of the resin composition. It is valid.

Examples of olefin elastomers include ethylene/propylene copolymer elastomer (EPR), ethylene/butene copolymer elastomer (EBR), ethylene/hexene copolymer elastomer (EHR), and ethylene/octene copolymer elastomer (EOR). ) and other ethylene/α-olefin copolymer elastomers; Examples include original copolymer elastomer and styrene-butadiene-styrene triblock copolymer elastomer (SBS).
Examples of styrene-based elastomers include styrene-isoprene-styrene triblock copolymer elastomer (SIS), styrene-ethylene-butylene copolymer elastomer (SEB), and styrene-ethylene-propylene copolymer elastomer (SEP). , styrene-ethylene/butylene-styrene copolymer elastomer (SEBS), styrene-ethylene/butylene-ethylene copolymer elastomer (SEBC), hydrogenated styrene-butadiene elastomer (HSBR), styrene-ethylene/propylene-styrene copolymer Polymer elastomer (SEPS), styrene-ethylene/ethylene/propylene-styrene copolymer elastomer (SEEPS), styrene-butadiene/butylene-styrene copolymer elastomer (SBBS), partially hydrogenated styrene-isoprene-styrene copolymer elastomer , styrene-based elastomers such as partially hydrogenated styrene-isoprene-butadiene-styrene copolymer elastomer, and hydrogenated polymer-based elastomers such as ethylene-ethylene-butylene-ethylene copolymer elastomer (CEBC).
Among them, when an ethylene-octene copolymer elastomer (EOR) and/or an ethylene-butene copolymer elastomer (EBR) is used, in a laminate having the above resin composition or a resin layer composed of the resin composition, It is preferable because it is easy to impart appropriate flexibility and tends to have excellent impact resistance.

<<Production method of resin composition>>
In the present invention, conventionally known methods can be used to produce the resin composition, and the resin composition can be produced by blending, mixing, and melt-kneading the above components.
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, or kneader. , melt-kneaded and granulated.

<Support layer>
The laminate constituting the battery housing of the present invention has a support layer laminated on at least one surface of the resin layer.
The support layer, together with the resin layer, imparts flame retardancy and flameproofing properties to the laminate constituting the battery housing of the present invention, and from the viewpoint of achieving these effects, it is made of fiber (X). A fibrous layer is preferable, and a nonwoven fabric layer made of a nonwoven fabric, a woven fabric layer made of a woven fabric, or a knitted fabric layer is particularly preferable.
In particular, non-woven fabrics are preferable compared to woven fabrics and knitted fabrics because a portion of the resin layer easily penetrates into the surface of the support layer, resulting in higher binding properties. Furthermore, since the fibers of the nonwoven fabric are oriented in an undefined direction, the nonwoven fabric is also preferable because its mechanical strength does not depend on the direction.

The thickness of the support layer is not particularly limited as long as it achieves the effects of the present invention, but it is preferably 0.01 mm or more. If it is 0.01 mm or more, the binding property with the resin layer will be good, and the resin layer can be maintained even if the resin layer is exposed to flame. From the above viewpoint, the thickness of the support layer is more preferably 0.05 mm or more, and even more preferably 0.1 mm or more.
On the other hand, the upper limit of the thickness of the support layer is preferably 5 mm or less, more preferably 2 mm or less, and 1 mm or less, from the viewpoint of suppressing the weight when formed into a molded product and from the cost perspective. It is more preferable that it is, and it is especially preferable that it is 0.5 mm or less.

The size of the fibers (X) constituting the fiber layer is not limited as long as the effects of the present invention can be achieved, but the average diameter of the fibers is preferably in the range of 3 to 25 μm; The fiber length is preferably in the range of 5 to 100 mm.
When the average fiber diameter is 3 μm or more, handling during the manufacturing process of the fiber layer is easy, and when it is 25 μm or less, breakage is difficult to occur. Further, when the average fiber length is 5 mm or more, flameproofing properties can be imparted to the laminate, and sufficient strength can be imparted. On the other hand, when the average fiber length is 100 mm or less, breakage is less likely to occur. The fiber length can be measured using a ruler, caliper, etc. from an image enlarged with a microscope, etc., if necessary.The average fiber length can be measured, for example, by randomly measuring the fiber length of 10 fibers and calculating the average value. It can be obtained by calculation.
The fibers (X) constituting the fiber layer are not particularly limited as long as they exhibit the effects of the present invention, and include glass fibers, carbon fibers, boron fibers, ceramic fibers, metal fibers, metal oxide fibers, etc. Examples include organic fibers such as inorganic fibers, aramid fibers, and aromatic polyester fibers. Among these, inorganic fibers are preferable from the viewpoint of obtaining excellent flameproofing properties, and among them, glass fibers, ceramic fibers, metal fibers, and metal oxide fibers are preferable, and glass fibers are particularly preferable.

As described above, among the fibers, at least one selected from the group consisting of glass fibers and aramid fibers is preferred. As will be described later, when the laminate is used in a battery pack, it is desired to have excellent flameproofing properties. In such a case, safety is required when the flame comes into contact with the resin layer side. Both glass fiber and aramid fiber can withstand flame contact from the resin layer side, but the present invention shows that when glass fiber is selected, it can also withstand flame contact from the support layer side constituting the laminate. They found out. Therefore, glass fiber is more preferable as the fiber (X) constituting the fiber layer.

<<Nonwoven layer>>
The nonwoven fabric layer is composed of nonwoven fabric. The fibers constituting the nonwoven fabric are not particularly limited as long as they exhibit the effects of the present invention, and include inorganic fibers such as glass fibers, carbon fibers, boron fibers, ceramic fibers, metal fibers, and metal oxide fibers, and aramid fibers. and organic fibers such as aromatic polyester fibers. Among these, inorganic fibers are preferable from the viewpoint of obtaining excellent flameproofing properties, and among them, glass fibers, ceramic fibers, metal fibers, and metal oxide fibers are preferable, and glass fibers are particularly preferable.

(Glass fiber nonwoven fabric)
Forms of the glass fiber nonwoven fabric suitably used in the present invention include felts and blankets processed with short fiber glass cotton, chopped strand mats processed with continuous glass fibers, swirl mats of continuous glass fibers, and unidirectionally drawn Examples include alignment mats. Among these, it is particularly preferable to use a glass fiber mat obtained by needle punching a swirl mat of continuous glass fibers because the strength and impact resistance of the laminate are excellent.
Note that the glass fibers are the same as those described above for (C) fibers.

The ceramic fiber is preferably a fiber mainly composed of silica and alumina, for example, in a range of silica:alumina=40:60 to 0:100, specifically, silica-alumina fiber, mullite fiber, alumina fiber. can be used.
Preferable materials for the metal fibers include fibers containing iron, copper, aluminum, nickel, tungsten, titanium, molybdenum, beryllium, platinum, or the like as a main component. Furthermore, in addition to the above-mentioned metals, one or more of carbon, nitrogen, chromium, cobalt, gold, silver, etc. may be included as an alloy component. Fibers containing stainless steel, nickel, or titanium as a main component are particularly preferred because of their excellent strength and corrosion resistance.
Materials for metal oxide fibers include, for example, alkaline earth metal oxides such as magnesium oxide and calcium oxide; Group 4 metal oxides such as titanium oxide and zirconium oxide; Group 13 elements such as alumina and indium oxide. oxides of Group 14 elements such as silica, tin oxide, and lead oxide; oxides of Group 15 elements such as antimony oxide, etc. can be used. Among these, oxide fibers of Group 13 to Group 15 elements are preferred, more preferred are oxide fibers of Group 13 elements, and particularly preferred are fibers containing oxides of Group 13 elements, since they can effectively obtain a high level of heat resistance. is alumina fiber.

The size of the fibers constituting the nonwoven fabric is not limited as long as the effects of the present invention can be achieved, but the average diameter of the fibers is preferably in the range of 3 to 25 μm, and the average fiber length is as follows: It is preferably in the range of 5 to 100 mm.
When the average fiber diameter is 3 μm or more, handling during the manufacturing process of the nonwoven fabric is easy, and when it is 25 μm or less, breakage is difficult to occur. Further, when the average fiber length is 5 mm or more, flameproofing properties can be imparted to the laminate, and sufficient strength can be imparted. On the other hand, when the average fiber length is 100 mm or less, breakage is less likely to occur. From the above viewpoint, the average fiber length is more preferably in the range of 10 to 50 mm, and even more preferably in the range of 15 to 30 mm.
Note that the average fiber length can be measured by the method described above.

The basis weight (fiber amount per unit area) of the nonwoven fabric is preferably in the range of 10 to 500 g/m ² . When the basis weight is 10 g/m ² or more, the flameproofing properties of the laminate and sufficient strength of the laminate can be obtained. On the other hand, if it is 500 g/m ² or less, the binding property with the resin layer will be good, sufficient flameproofing properties of the laminate will be obtained, and the weight will not become excessively large. From the above viewpoint, the basis weight is more preferably in the range of 20 to 300 g/m ² , even more preferably in the range of 30 to 150 g/m ² , and particularly preferably in the range of 35 to 100 g/m ² .
Within the above range of 35 to 100 g/m ² , the basis weight is preferably 35 to 75 g/m ² , more preferably 35 to 70 g/m ² , even more preferably 35 to 45 g/m ² . Although not bound by any particular theory, it is believed that the lower the basis weight is, the more easily the resin composition containing the flame retardant permeates through the resin layer, leading to better flame-blocking properties as a whole.

As a method for manufacturing the nonwoven fabric, conventionally known methods can be used, such as a dry method, a wet method, a spunbond method, a melt plane method, an air laid method, etc. Further, as a method for bonding the fibers of the nonwoven fabric obtained by these manufacturing methods, known methods such as a chemical bond method, a thermal bond method, a needle punch method, and a hydroentangling method can be used.

<<Woven fabric layer>>
The woven fabric layer is made of a woven fabric. The fibers constituting the woven fabric are not particularly limited as long as they can produce the effects of the present invention, and the same fibers as those exemplified for the nonwoven fabric layer can be used. As with the nonwoven fabric layer, inorganic fibers are preferred, and glass fibers are particularly preferred.
The size (average fiber diameter, average fiber length) and basis weight of the fibers constituting the woven fabric are also the same as those described for the nonwoven fabric layer.
The weave of the woven fabric made of the above fibers is not particularly limited, and may be any of plain weave, twill weave, satin weave, and the like.

<<Knitted fabric layer>>
The knitted fabric layer is composed of knitted fabric. The fibers constituting the knitted fabric are not particularly limited as long as they exhibit the effects of the present invention, and the same fibers as those exemplified for the above-mentioned nonwoven fabric layer can be used. Note that, similarly to the nonwoven fabric layer, inorganic fibers are preferred, and glass fibers are particularly preferred.
The size (average fiber diameter, average fiber length) and basis weight of the fibers constituting the knitted fabric are also the same as those described for the nonwoven fabric layer.
The structure of the knitted fabric made of the above-mentioned fibers is not particularly limited, and may be any of rubber knitting, garter knitting, stockinette knitting, and the like.

<Method for manufacturing laminate>
In the present invention, the method for manufacturing the laminate is not particularly limited, and various known methods can be used. Specifically, there are methods such as forming a resin layer and a support layer in advance and pasting them together, and setting the support layer in a mold and injection molding by pouring a resin composition to form the resin layer. Can be mentioned.
As a method for bonding, for example, there is a method in which a resin sheet for configuring the resin layer and a glass fiber nonwoven fabric sheet for configuring the support layer are prepared in advance, and then these are laminated and heated and pressurized.
More specifically, it is a method of press-molding a resin sheet and a glass fiber nonwoven fabric sheet in a mold equipped with a heating device.

The heating temperature is preferably 170 to 300°C. When the heating temperature is 170° C. or higher, sufficient bonding between the resin layer and the support layer is achieved, and the flameproofing properties of the laminate are improved. On the other hand, when the heating temperature is 300° C. or lower, the resin composition constituting the resin layer does not deteriorate.
Further, the pressurizing pressure is preferably 0.1 to 1 MPa. When the applied pressure is 0.1 MPa or more, sufficient bonding between the resin layer and the support layer is achieved, and the flameproofing properties of the laminate are improved. On the other hand, by setting the pressure to 1 MPa or less, burrs do not occur in the resin layer.
When bonding the resin layer and the support layer, an adhesive layer may be provided between the resin layer and the support layer. However, in the present invention, since the binding property between the resin layer and the support layer is important, it is preferable that the resin layer and the support layer are directly bound without intervening another layer.
Note that the temperature during cooling is not particularly limited as long as it is below the freezing point of the thermoplastic resin, but if the cooling temperature is 80° C. or below, the obtained molded product will not be deformed when taken out. From the above viewpoint, the cooling temperature is preferably room temperature to 80°C.

Alternatively, a laminate can be manufactured by laminating a resin sheet and a glass fiber nonwoven fabric sheet by passing them between two pairs of rollers equipped with a heating device and applying heat and pressure. Lamination processing is preferable because it allows continuous production and has good productivity.

Further, as a method of manufacturing the laminate by injection molding, for example, a method as shown in FIG. 6 can be used. That is, the method is to set the glass nonwoven fabric 15 in the movable mold 21, fit the movable mold 21 into the fixed mold 22, inject the resin composition 16 into the cavity, and integrally mold the resin composition 16 and the glass nonwoven fabric 15. . By this method, it is possible to obtain the laminate 10 constituting the battery housing of the present invention, in which the support layer 11 is laminated on one side of the resin layer 12. When this injection molding method is used, the long fibers in the glass nonwoven fabric are maintained without being broken, so that the flameproofing properties of the battery housing of the present invention can be further improved.
When manufacturing the battery housing of the present invention by injection molding, a base fabric such as a nonwoven glass fabric for forming a support layer is set in a mold for manufacturing a battery housing having a desired shape, and the mold is clamped. A preferred method is to inject the resin composition into the cavity after molding.

The battery housing of the present invention can be used for various batteries, and the batteries are not particularly limited. Examples include secondary batteries such as lithium ion batteries, nickel-hydrogen batteries, lithium-sulfur batteries, nickel-cadmium batteries, nickel-iron batteries, nickel-zinc batteries, sodium-sulfur batteries, lead-acid batteries, and air batteries. Among these, lithium ion batteries are preferred, and are particularly suitable for suppressing thermal runaway of lithium ion batteries.
It is useful for electric mobility such as vehicles that operate using electricity as an energy source, transportation equipment such as ships and airplanes, and vehicles include hybrid cars in addition to electric vehicles (EVs).
The battery housing of the present invention has high safety and is very useful for electric mobility using battery modules with high energy density in order to extend driving distance. In the event that the battery ignites, the battery housing of the present invention has high flame-retardant properties, so time is secured for the driver and passenger to evacuate.

EXAMPLES Hereinafter, the present invention will be explained in detail using Examples, but the present invention is not limited to these Examples.
(Evaluation method)
Evaluation of flame resistance (1)
As shown in FIG. 3, the laminates (injection test pieces) prepared in each Example and Comparative Example were exposed to a 1200°C burner flame from the resin layer 12 side surface, and the flame penetrated after 15 minutes. It was evaluated based on whether or not it was. The evaluation criteria are as follows. In addition, as an injection test piece, the below-mentioned evaluation sample was used.
Evaluation criteria A: Flame did not penetrate B: Flame penetrated

Evaluation of flame resistance (2)
Regarding the laminates (injection test pieces) prepared in each example and comparative example, as shown in FIG. It was measured.

Flameproof evaluation (3)
Flame contact evaluation was performed on the laminates (injection test pieces) prepared in each Example and Comparative Example as follows. In addition, as an injection test piece, the below-mentioned evaluation sample was used.
(i) As shown in FIG. 7, a 1200° C. burner flame was applied from the resin layer 12 side surface, and evaluation was made by whether the flame penetrated after 15 minutes. The evaluation criteria are as follows.
(ii) As shown in FIG. 7, a 1200° C. burner flame was applied from the surface of the support layer 11 side, and evaluation was made by whether the flame penetrated after 15 minutes. The evaluation criteria are as follows.
Evaluation criteria A: Flame did not penetrate B: Flame penetrated

Example 1
(1) Preparation of resin composition The following materials were prepared as raw materials for the resin composition.
(a) Polypropylene resin ((A) component)
"Novatec (registered trademark) BC03B" manufactured by Nippon Polypro Co., Ltd. (melt flow rate: 30 g/10 minutes)
(b) Flame retardant ((B) component)
Phosphorous flame retardant (manufactured by ADEKA Co., Ltd., ADEKA STAB FP-2500S, non-halogen intumescent flame retardant)
(c) Dispersant ((D) component)
α-olefin/maleic anhydride copolymer (manufactured by Mitsubishi Chemical Corporation, Diacarna 30M, weight average molecular weight 7,800)
(d) Antioxidant (d-1) Phenolic antioxidant (manufactured by ADEKA Co., Ltd., ADEKA STAB AO-60)
(d-2) Phosphite-based antioxidant (manufactured by ADEKA Co., Ltd., ADEKA STAB 2112)
(e) Glass fiber reinforced thermoplastic resin (GF reinforced resin, component (A) + component (C))
"Funkster (registered trademark)" manufactured by Nippon Polypro Co., Ltd. (polypropylene resin/glass fiber = 50/50, pellet length 10 mm)

The above (a) polypropylene resin, (b) flame retardant, (c) dispersant, and (d) antioxidant are mixed so that each component has the ratio shown in Table 1 below, and (e) GF The reinforcing resins were mixed to prepare a resin composition. Although not listed in Table 1, the ratio of the phenolic antioxidant (d-1) and the phosphite antioxidant (d-2) to 100 parts by mass of the resin composition is as follows: In each case, the content was 0.007 part by mass.

(2) Manufacture of laminate The following materials were prepared as raw materials for the laminate.
(f) Support layer (f-1) Glass nonwoven fabric (manufactured by Oji F-Tex Co., Ltd., GMC-50G, basis weight 50 g/m ² , thickness 0.36 mm)
(f-2) Glass nonwoven fabric (manufactured by Oji F-Tex Co., Ltd., GMC-75G, basis weight 75 g/m ² , thickness 0.53 mm)
(f-3) Glass nonwoven fabric (Olivest Co., Ltd., FAP-035, basis weight 35 g/m ² , thickness 0.26 mm)
(f-4) Aramid nonwoven fabric (manufactured by Oji F-Tex Co., Ltd., APT36, basis weight 36 g/m ² , thickness 0.50 mm)

Examples 1 and 6
The resin composition obtained in the above (1) was laminated on the (f) support layer using an injection molding machine "FANUC ROBOSHOT α-S300iA" manufactured by FANUC Corporation to produce a sample for flame retardant evaluation. did.
Specifically, by placing (f-1) glass nonwoven fabric in a mold in advance and injection molding a resin composition having the composition shown in Table 1 thereon, a mold having a length of 200 mm x width of 200 mm x thickness of 2 A test piece (1) of .0 mm and a test piece (2) of 200 mm in length x 200 mm in width x 3.5 mm in thickness were prepared, respectively. The final formulations are shown in Table 2-1 and Table 2-2. Note that the glass fibers in Tables 2-1 and 2-2 also include glass fibers derived from the (f-1) support layer.
For example, the thickness of the resin layer of the evaluation sample (laminate) obtained in Example 1 was 1.86 mm, and the thickness of the nonwoven fabric layer (supporting layer) was 0.14 mm. Therefore, the thickness of the resin layer was 13.3 times the thickness of the support layer. The thicknesses of the resin layer and support layer of evaluation samples in other Examples are as shown in Table 2-2. In addition, regarding Example 1, evaluation (3) of flameproofing property was also performed. Also shown.
Tables 2-1 and 2-2 show the results of flameproofing evaluation using the obtained evaluation samples. The main molding conditions are as follows.
1) Temperature conditions: cylinder temperature (220℃), mold temperature (60℃)
2) Injection conditions: injection pressure (200MPa), holding pressure (82MPa)
3) Measurement conditions: screw rotation speed (50 rpm), back pressure (15 MPa)

Examples 2, 7 and 10
In Examples 2 and 7, evaluation samples were obtained in the same manner as in Examples 1 and 6, except that (f-2) was used instead of (f-1) in Examples 1 and 6, respectively. Example 10 was the same as Example 1 except that (f-2) was used instead of (f-1) and the test piece (3) was 200 mm long x 200 mm wide x 1.5 mm thick. A sample for evaluation was obtained.
For example, the thickness of the resin layer of the evaluation sample (laminate) obtained in Example 2 was 1.84 mm, and the thickness of the nonwoven fabric layer (support layer) was 0.16 mm. Therefore, the thickness of the resin layer was 11.5 times the thickness of the support layer. The thicknesses of the resin layer and support layer of evaluation samples in other Examples are as shown in Table 2-2. Tables 2-1 and 2-2 show the results of flameproofing evaluation using the obtained evaluation samples.

Examples 3 and 8
In Examples 3 and 8, evaluation samples were obtained in the same manner as in Examples 1 and 6, except that two sheets of (f-2) were used instead of (f-1) in each of Examples 1 and 6. .
For example, the thickness of the resin layer of the evaluation sample (laminate) obtained in Example 3 was 1.73 mm, and the thickness of the nonwoven fabric layer (support layer) was 0.27 mm. Therefore, the thickness of the resin layer was 6.4 times the thickness of the support layer. The thicknesses of the resin layer and support layer of evaluation samples in other Examples are as shown in Table 2-2. Tables 2-1 and 2-2 show the results of flameproofing evaluation using the obtained evaluation samples.

Examples 4, 9, 11 and 12
In Examples 4 and 9, evaluation samples were obtained in the same manner as in Examples 1 and 6, except that (f-3) was used instead of (f-1) in Examples 1 and 6, respectively. Example 11 was the same as Example 1 except that (f-3) was used instead of (f-1) and the test piece (3) was 200 mm long x 200 mm wide x 1.5 mm thick. A sample for evaluation was obtained. Example 12 was the same as Example 1 except that (f-3) was used instead of (f-1) and the test piece (4) was 200 mm long x 200 mm wide x 1.0 mm thick. A sample for evaluation was obtained.
For example, the thickness of the resin layer of the evaluation sample (laminate) obtained in Example 4 was 1.89 mm, and the thickness of the nonwoven fabric layer (support layer) was 0.11 mm. Therefore, the thickness of the resin layer was 17.2 times the thickness of the support layer. The thicknesses of the resin layer and support layer of evaluation samples in other Examples are as shown in Table 2-2. Tables 2-1 and 2-2 show the results of flameproofing evaluation using the obtained evaluation samples. In addition, regarding Example 4, evaluation (3) of flameproofing properties was also conducted. Also shown.

Example 5
An evaluation sample was obtained in the same manner as in Example 1 except that (f-4) was used instead of (f-1). The thickness of the resin layer of the obtained evaluation sample (laminate) was 1.83 mm, and the thickness of the nonwoven fabric layer (supporting layer) was 0.17 mm. Therefore, the thickness of the resin layer was 10.8 times the thickness of the support layer. Table 2-1 shows the results of flameproofing evaluation using the obtained evaluation samples. In addition, flameproofing property evaluation (3) was also conducted. Also shown.

Comparative example 1
A test piece was obtained in the same manner as in Example 1 except that (f) the support layer was not used. The test piece is a molded body consisting only of a resin layer. Flameproofing properties were evaluated in the same manner as in Example 1. The results are shown in Table 2-1.

Even when the laminates of Examples 1 to 12 were exposed to a 1200° C. burner flame for 15 minutes, the flame did not penetrate and showed very good results. On the other hand, when the molded article of Comparative Example 1 was exposed to a burner flame under the same conditions, the flame penetrated after about 90 seconds.

Since the battery housing according to the present invention has extremely excellent flameproofing properties, it is useful as a material for various industrial parts that require high safety, such as aircraft, ships, automobile parts, electrical and electronic equipment parts, and construction materials. In particular, it can be suitably used for various battery housings and casings, which have traditionally been made of metal, and is expected to contribute to automobile safety, improve energy efficiency through weight reduction, and reduce _CO2 emissions. Ru.

10 Laminated body 11 Support layer 12 Resin layer 13 Flame retardant 14 Fiber 15 Support layer 16 Resin composition 21 Movable type 22 Fixed type 100 Battery 110 Battery module 120 Battery pack 130 Battery housing

Claims (17)

A battery housing having a resin layer containing a flame retardant and a support layer laminated on at least one surface of the resin layer, characterized in that the resin layer and the support layer are arranged in this order from the battery storage section side. The battery housing according to claim 1, wherein the resin layer is made of a resin composition containing (A) a thermoplastic resin and (B) a flame retardant, and the support layer is a fiber layer made of fibers (X). . The battery housing according to claim 2, wherein the fiber layer is a nonwoven fabric layer made of a nonwoven fabric, a woven fabric layer made of a woven fabric, or a knitted fabric layer made of a knitted fabric. The battery housing according to claim 2 or 3, wherein the average fiber length of the fibers (X) constituting the fiber layer is 5 to 100 mm. The battery housing according to claim 2, wherein the resin composition further contains (C) fibers, and the average fiber length of the fibers is 0.05 to 100 mm. The battery housing according to claim 2, wherein the resin composition further includes (D) a dispersant. The battery housing according to claim 1, wherein the resin layer has a thickness of 0.5 to 50 mm. The battery housing according to claim 2, wherein the flame retardant (B) includes a phosphorus-based flame retardant. The battery housing according to claim 2, wherein the flame retardant (B) includes an intumescent flame retardant. The battery housing according to claim 2 or 3, wherein the fibers (X) constituting the fiber layer include inorganic fibers. The battery housing according to claim 10, wherein the inorganic fibers constituting the fiber layer include at least one selected from the group consisting of glass fibers, ceramic fibers, metal fibers, and metal oxide fibers. The battery housing according to claim 5, wherein the (C) fibers include inorganic fibers. The battery housing according to claim 12, wherein the inorganic fiber includes at least one selected from the group consisting of glass fiber, ceramic fiber, metal fiber, and metal oxide fiber. The battery housing according to claim 6, wherein the dispersant (D) includes a copolymer of an α-olefin and an unsaturated carboxylic acid. The battery housing according to claim 2, wherein the thermoplastic resin (A) includes a polypropylene resin, and the content of the polypropylene resin in the resin composition is 15 to 80% by mass. The battery housing according to claim 2, wherein the content of the flame retardant (B) in the resin composition is 1 to 40% by mass. The battery housing according to claim 6, wherein the content of the dispersant (D) is 0.1 to 20 parts by mass based on 100 parts by mass of the flame retardant (B).