JP2024060486A - Laminate and molded body using same - Google Patents

Abstract

[Problem] To provide a laminate having high flame blocking properties, flame resistance and heat insulation properties. [Solution] A laminate including a layer (A) in which a thermoplastic resin composition (X) and inorganic fibers (Y) are integrated, and a thermoplastic resin layer (B), in which layer (B) is disposed so that one surface thereof is adjacent to layer (A) and the other surface thereof serves as a surface layer, the thermoplastic resin composition (X) includes a thermoplastic resin and a halogen-free flame retardant, and the thermoplastic resin layer (B) includes a thermoplastic resin having a melt flow rate (MFR, 230°C, 2.16 kg load) of 0.05 to 30 g/10 min. [Selected Figure] None

Description

The present invention relates to a laminate and a molded body using the same.

In recent years, research and development of electric and hybrid vehicles has been promoted as part of environmental measures, and the development of high-energy density batteries and weight reduction are being actively promoted in order to improve the driving range. Such high-energy density batteries are at risk of catching fire in the event of an accident, so as a safety measure for passengers, the housing material must have high flame retardancy, and therefore, in many cases, metal materials such as iron are used in combination with fire-resistant materials.
However, metal materials have the drawback of being heavy, and when fire-resistant materials are used in combination, issues arise regarding workability and increased costs due to the increased number of parts. Therefore, attempts are being made to use resins, which have the potential to achieve both weight reduction and flame resistance. Currently, in order to create a sustainable society, emphasis is being placed on reducing carbon dioxide emissions and recyclability. Many thermosetting materials have high flame retardancy and are common as composite materials, but in terms of recyclability, thermoplastic resin materials are advantageous.

In addition, China has announced a safety standard called GB 38031-2020 "Safety Requirements for Electric Vehicle Power Batteries," which requires that a warning be issued five minutes before the battery experiences thermal runaway. It is believed that this can be achieved by using housing materials that provide flame protection for at least five minutes after the battery ignites.

To address these issues, for example, Patent Document 1 proposes adding a brominated flame retardant or an antimony oxide compound to a carbon fiber reinforced polypropylene resin, but the additives used therein have a problem in terms of their persistence in living organisms.
In response to this, Patent Document 2 proposes a flame-retardant polyolefin-based composition in which a polyolefin-based resin contains a (poly)phosphate compound, as a technology for making polypropylene-based resin flame-retardant while taking into consideration bioretention.
Moreover, Patent Document 3 proposes a flame-retardant resin composition comprising a polypropylene resin, long glass fibers, and a phosphate compound.

JP 2014-62189 A JP 2013-119575 A JP 2011-88970 A

Conventional fiber-reinforced composite material technology, which has the potential to achieve both lightweight and flame-resistant properties in high-energy density batteries, has many shortcomings. Specifically, stampable sheets that are fiber-reinforced composite materials are required to have high flame-resistant properties and further improved insulation properties.

The present invention was made to solve the above problems, and aims to provide a laminate that combines high flame blocking properties, flame resistance, and heat insulation properties.

Means for Solving the Problems The present inventors conducted intensive research to solve the above problems, and as a result, found that the above problems can be solved by a laminate having a layer in which a thermoplastic resin composition containing a non-halogen-based flame retardant is integrated with inorganic fibers, and a layer containing a thermoplastic resin having specific physical properties. Based on these findings, the present inventors have completed the present invention.
That is, the present invention provides the following [1] to [10].
[1] A laminate including a layer (A) in which a thermoplastic resin composition (X) and inorganic fibers (Y) are integrated, and a thermoplastic resin layer (B), in which the layer (B) is disposed so that one surface thereof is adjacent to the layer (A) and the other surface thereof serves as a surface layer, the thermoplastic resin composition (X) includes a thermoplastic resin and a halogen-free flame retardant, and the thermoplastic resin layer (B) includes a thermoplastic resin having a melt flow rate (MFR, 230°C, 2.16 kg load) of 0.05 to 30 g/10 min.
[2] The laminate according to the above [1], wherein the non-halogen flame retardant is a phosphorus-based flame retardant.
[3] The laminate according to the above [1] or [2], wherein the thermoplastic resin composition (X) further contains a dispersant.
[4] The laminate according to the above [3], wherein the dispersant is a copolymer of an α-olefin and an unsaturated carboxylic acid.
[5] The laminate according to the above [3] or [4], wherein the content of the dispersant per 100 parts by mass of the phosphorus-based flame retardant is more than 0 and not more than 25 parts by mass.
[6] The laminate according to any one of the above [1] to [5], wherein the inorganic fibers (Y) have an average fiber length of 0.1 mm or more.
[7] The laminate according to any one of the above [1] to [6], wherein the inorganic fiber (Y) is at least one selected from glass fibers, ceramic fibers, metal fibers, and metal oxide fibers.
[8] The laminate according to any one of the above [1] to [7], wherein the thermoplastic resin constituting the thermoplastic resin composition (X) and the thermoplastic resin constituting the thermoplastic resin layer (B) are polypropylene-based resins, and the content of the polypropylene-based resin is 15 to 80 mass% based on the total mass.
[9] The laminate according to any one of the above [1] to [8], wherein the content of the non-halogen flame retardant is 1 to 30 mass% based on the total mass.
[10] A molded article obtained by stamping the laminate according to any one of [1] to [9] above.

The present invention provides a laminate that combines flame blocking, flame resistance, and heat insulation properties.

FIG. 2 is a schematic diagram showing an embodiment of one layer structure in the laminate of the present invention. FIG. 2 is a schematic diagram showing another embodiment of a layer structure in the laminate of the present invention. FIG. 2 is a schematic diagram showing another embodiment of a layer structure in the laminate of the present invention. FIG. 1 is a schematic diagram showing a layer structure of a laminate in Example 1 of the present invention (before impregnation). FIG. 2 is a schematic diagram showing a layer structure of a laminate in Example 1 of the present invention (after impregnation). FIG. 10 is a schematic diagram showing a layer structure of a laminate in Example 3 of the present invention (before impregnation). FIG. 11 is a schematic diagram showing a layer structure of a laminate in Example 3 of the present invention (after impregnation).

The following describes in detail the embodiments of the present invention, but the following description is merely an example of an embodiment of the present invention, and the present invention is not limited to these contents in any way.

[Laminate]
The present invention is a laminate including a layer (A) (hereinafter, sometimes simply referred to as "layer (A)") in which a thermoplastic resin composition (X) and inorganic fibers (Y) are integrated, and a thermoplastic resin layer (B) (hereinafter, sometimes simply referred to as "layer (B)"). The layer (B) is disposed so that one surface thereof is adjacent to the layer (A) and the other surface thereof serves as a surface layer. The thermoplastic resin composition (X) is characterized in that it contains (a) a thermoplastic resin and (b) a halogen-free flame retardant, and the thermoplastic resin layer (B) contains a thermoplastic resin having a melt flow rate (MFR, 230°C, 2.16 kg load) of 0.05 to 30 g/10 min.

The structure of the laminate of the present invention may be a laminate (A/B) in which a layer (B) is laminated on one surface (front surface) of a layer (A) as shown in Fig. 1, or an embodiment (B/A/C) in which a layer (B) is laminated on a layer (A) (front surface) and another layer (C) is laminated on the back surface side as shown in Fig. 2. Also, an embodiment (B/A/B) in which a layer (B) is laminated on both surfaces of a layer (A) as shown in Fig. 3 may be used.
The other layer (C) (hereinafter, may be simply referred to as "layer (C)") laminated on the back surface side is not particularly limited, but is preferably a resin layer, and may have the same resin composition as the thermoplastic resin composition (X) constituting the layer (A).

The thickness ratio of layer (A) to layer (B) (thickness of layer (A)/thickness of layer (B)) is not particularly limited, but is preferably 10/90 to 50/50. If it is 10/90 or more, sufficient flame retardancy and heat insulation can be exhibited. If it is 50/50 or less, sufficient moldability can be ensured. From the same viewpoint, the thickness ratio of layer (A) to layer (B) (thickness of layer (A)/thickness of layer (B)) is more preferably 15/85 to 45/55, and even more preferably 20/80 to 40/60. When the laminate has multiple layers (A) and layers (B), the above thickness ratio is calculated with respect to the total thickness of the multiple layers (A) and layers (B).

[Thermoplastic resin composition (X)]
The thermoplastic resin composition (X) according to the present invention contains at least (a) a thermoplastic resin and (b) a non-halogen-based flame retardant. Hereinafter, the (a) thermoplastic resin and the (b) non-halogen-based flame retardant will be described in detail.

<(a) Thermoplastic resin>
The thermoplastic resin constituting the layer (A) in the present invention is not particularly limited, but it is essential that the thermoplastic resin constituting the layer (B) has a melt flow rate (MFR, 230°C, 2.16 kg load) of 0.05 to 30 g/10 min.
Examples of the thermoplastic resin include polyolefin resin, polycarbonate resin, polyester resin, acrylonitrile styrene resin, ABS resin, polyamide resin, modified polyphenylene oxide, etc. Among these, polyolefin resin is preferred in the present invention. These may be used alone or in combination of two or more. For example, the (a) thermoplastic resin may be a composite resin of two or more of the above thermoplastic resins.

The polyolefin resin is not particularly limited, and examples thereof include the resins described below. The polyester resin is not particularly limited, and examples thereof include polybutylene terephthalate. The polyamide resin is not particularly limited, and examples thereof include nylon 66 and nylon 6.
Among them, the present invention is particularly useful when 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 proportion of olefin units or cycloolefin units is 90 mol % or more relative to 100 mol % of all structural units constituting the resin.
The proportion of olefin units or cycloolefin units relative to 100 mol % of all structural units constituting the polyolefin resin is preferably 95 mol % or more, and particularly preferably 98 mol % or more.

Examples of polyolefin resins include α-olefin polymers such as polyethylene, polypropylene, polybutene, poly(3-methyl-1-butene), poly(3-methyl-1-pentene), and poly(4-methyl-1-pentene); α-olefin copolymers such as ethylene-propylene block or random copolymers, α-olefin-propylene block or random copolymers having 4 or more carbon atoms, ethylene-methyl methacrylate copolymers, and ethylene-vinyl acetate copolymers; and 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, hemiisotactic polypropylene, and stereoblock polypropylene. In the α-olefin-propylene block or random copolymers having 4 or more carbon atoms, examples of the α-olefins having 4 or more carbon atoms include butene, 3-methyl-1-butene, 3-methyl-1-pentene, and 4-methyl-1-pentene. These polyolefin resins may be used alone or in combination of two or more.
Of the above olefin resins, polypropylene resin (hereinafter sometimes referred to as "PP resin") is particularly preferred.

(Melt Flow Rate (MFR))
The melt flow rate (hereinafter sometimes abbreviated as MFR) (230°C, 2.16 kg load) of the thermoplastic resin constituting the layer (A) used in the present invention is preferably 40 to 500 g/10 min. If the MFR is 40 g/10 min or more, for example, no chipping occurs when the laminate is stamped, and the processability does not decrease. Also, if it is 500 g/10 min or less, no burrs are generated during the production of the laminate. From the above viewpoints, the MFR is preferably 50 to 400 g/10 min, more preferably 60 to 400 g/10 min, and more preferably 70 to 300 g/10 min.
The MFR of the (a) thermoplastic resin can be adjusted, for example, by controlling the hydrogen concentration during polymerization.
The MFR is a value measured in accordance with JIS K7210.

On the other hand, the MFR of the thermoplastic resin constituting the layer (B) is 0.05 to 30 g/10 min. When the MFR of the thermoplastic resin constituting the layer (B) is in this range, the viscosity is relatively high and the molecular weight is large. Therefore, since it is difficult to impregnate the inorganic fiber (Y) constituting the layer (A), it tends to become a layer with a high resin content that is separated from the inorganic fiber (Y). When the layer (B) having such a tendency is arranged on the flame contact side, it is difficult for thermal decomposition by flame to occur, and the flame retardant contained in the layer (A) is likely to form char. This can improve the flame barrier property and fire resistance.
From the above viewpoints, the MFR of the thermoplastic resin constituting the layer (B) is preferably in the range of 0.05 to 30 g/10 min, and more preferably in the range of 0.1 to 10 g/10 min.

In addition, when layer (B) is placed on the side opposite the flame-contacting side, smoke generation can be suppressed. The inventors found that smoke generation mainly occurs on the side opposite the flame-contacting surface, and this embodiment is based on this finding. It is believed that when the MFR of the thermoplastic resin constituting layer (B) is 0.05 to 30 g/10 min, the thermoplastic resin is less likely to undergo thermal decomposition, and smoke is therefore less likely to be generated.

From the above viewpoints, the most preferable layer configuration of the laminate of the present invention is the configuration (B/A/B) in which layer (B) is laminated on both sides of layer (A) among the configurations described above. In this configuration, flame-proofing properties, heat insulation properties, and suppression of smoke generation can be effectively achieved.

((a) Thermoplastic Resin Content)
The content of the thermoplastic resin (a) in the laminate of the present invention (the total amount used in layers (A) and (B)) is not particularly limited, but is preferably 15 to 80% by mass. When the content of the thermoplastic resin is 15% by mass or more, the molding processability is particularly good, and molding of the laminate is easy. On the other hand, when the content is 80% by mass or less, the flame retardant, dispersant, and inorganic fibers can be contained in sufficient amounts, and good flame blocking properties can be obtained. From the above viewpoints, the content of the thermoplastic resin in the laminate is preferably 35 to 75% by mass, and more preferably 40 to 70% by mass.

<(a-1) Polypropylene Resin>
The thermoplastic resin (a) used in the laminate of the present invention preferably contains a polypropylene-based resin. Examples of the polypropylene-based resin include a propylene homopolymer and a propylene-α-olefin copolymer. Here, 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-1-butene, 1-heptene, methyl-1-hexene, dimethyl-1-pentene, ethyl-1-pentene, trimethyl-1-butene, and 1-octene. One of these may be copolymerized with propylene, or two or more may be copolymerized with propylene. Among them, from the viewpoint of improving the impact strength of the laminate, ethylene or 1-butene, which have a large effect, are preferred, and ethylene is most preferred.

(Propylene-ethylene random copolymer)
In the case of a random copolymer of propylene and ethylene, it preferably contains 90 to 99.5% by mass, more preferably 92 to 99% by mass, of propylene units and preferably 0.5 to 10% by mass, more preferably 1 to 8% by mass of ethylene units. When the ethylene units are equal to or more than the lower limit, sufficient impact strength of the laminate is obtained, and when the ethylene units are equal to or less than the upper limit, sufficient rigidity is maintained.
The contents 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.
The propylene content of the random copolymer of propylene and ethylene is a value measured using a cross fractionation device, FT-IR, or the like, and the measurement conditions and the like may be, for example, those described in JP-A-2008-189893.

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

(Acid-modified polyolefin resin)
Examples of acid-modified polyolefin resins include those obtained by graft copolymerizing polyolefins such as polyethylene, polypropylene, ethylene-α-olefin copolymers, ethylene-α-olefin-non-conjugated diene compound copolymers (such as EPDM), and ethylene-aromatic monovinyl compound-conjugated diene compound copolymer elastomers with unsaturated carboxylic acids such as maleic acid or maleic anhydride, thereby chemically modifying the polyolefins.
The 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. The unsaturated carboxylic acid or its derivative component can also be introduced into the polymer chain by random or block copolymerization with a polyolefin monomer.

Examples of unsaturated carboxylic acids used for modification include compounds having a carboxyl group, such as maleic acid, fumaric acid, itaconic acid, acrylic acid, and methacrylic acid, and a polymerizable double bond into which a functional group, such as a hydroxyl group or an amino group, has been introduced as necessary.
Derivatives of unsaturated carboxylic acids include their acid anhydrides, esters, amides, imides, metal salts, etc., and specific examples thereof include maleic anhydride, itaconic anhydride, methyl acrylate, ethyl acrylate, butyl acrylate, methyl methacrylate, etc. Of these, maleic anhydride is preferred.

Preferred acid-modified polyolefin resins include those modified by graft polymerization of maleic anhydride to an olefin polymer having ethylene and/or propylene as the main polymer unit, and those modified by copolymerization of an olefin mainly consisting of ethylene and/or propylene with 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 an appropriate site, for example, at the end of the main chain or on 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, and copolymers of the above-mentioned α-olefins with copolymerizable monomers.
Examples of preferred hydroxy-modified polyolefin resins include hydroxy-modified polyethylene resins such as low-, medium- or high-density polyethylene, linear low-density polyethylene, ultra-high molecular weight polyethylene, ethylene-(meth)acrylic acid ester copolymers, and ethylene-vinyl acetate copolymers; and hydroxy-modified polypropylene resins such as polypropylene homopolymers such as isotactic polypropylene, random copolymers of propylene and α-olefins (e.g., ethylene, butene, hexane, etc.), propylene-α-olefin block copolymers, and hydroxy-modified poly(4-methylpentene-1).

<(b) Halogen-free flame retardant>
The thermoplastic resin composition (X) forming the layer (A) constituting the laminate of the present invention contains (a) a thermoplastic resin and (b) a non-halogen flame retardant. The non-halogen flame retardant is a preferred flame retardant from the viewpoint of environmental conservation. The (b) non-halogen flame retardant is not particularly limited, and examples thereof include phosphorus-based flame retardants and antimony-based flame retardants. Among them, phosphorus-based flame retardants are preferred from the viewpoint of non-bioresiduality, excellent flame retardancy, and improved flame retardancy. In addition, in the classification focusing on the action mechanism of the flame retardant, intumescent flame retardants are preferred from the viewpoint of improved flame retardancy.
The flame retardants may be used alone or in combination of two or more.

(Phosphorus-based flame retardant)
The phosphorus-based flame retardant is a phosphorus compound, i.e., a compound containing a phosphorus atom in the molecule, and exerts a flame retardant effect by forming char when the resin composition is burned.
The phosphorus-based flame retardant may be a known one, and examples thereof include (poly)phosphates, (poly)phosphate esters, etc. Here, "(poly)phosphates" refers to phosphates or polyphosphates, and "(poly)phosphate esters" refers to phosphate esters or polyphosphate esters.
The phosphorus-based flame retardant is preferably solid at 80°C.

As the phosphorus-based flame retardant, (poly)phosphates are preferred in terms of flame retardancy.
Examples of (poly)phosphates include ammonium polyphosphate, melamine polyphosphate, piperazine polyphosphate, piperazine orthophosphate, melamine pyrophosphate, piperazine pyrophosphate, melamine polyphosphate, melamine orthophosphate, calcium phosphate, and magnesium phosphate.
In addition, in the above examples, compounds in which melamine or piperazine is replaced with other nitrogen compounds can be used in the same manner. Examples of other nitrogen compounds include N,N,N',N'-tetramethyldiaminomethane, ethylenediamine, N,N'-dimethylethylenediamine, N,N'-diethylethylenediamine, N,N-dimethylethylenediamine, N,N-diethylethylenediamine, N,N,N',N'-tetramethylethylenediamine, N,N,N',N'-diethylethylenediamine, 1,2-propanediamine, 1,3-propanediamine, tetramethyl Diamine, pentamethylenediamine, hexamethylenediamine, 1,7-diaminoheptane, 1,8-diaminooctane, 1,9-diaminononane, 1,10-diaminodecane, trans-2,5-dimethylpiperazine, 1,4-bis(2-aminoethyl)piperazine, 1,4-bis(3-aminopropyl)piperazine, acetoguanamine, benzoguanamine, acrylguanamine, 2,4-diamino-6-nonyl-1,3,5-triamine 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, Examples of such (poly)phosphates include 3,5-triazine, 2-amino-4,6-dimercapto-1,3,5-triazine, ammeline, benzguanamine, acetoguanamine, phthalodiguanamine, melamine cyanurate, melamine pyrophosphate, butylenediguanamine, norbornenediguanamine, methylenediguanamine, ethylenedimelamine, trimethylenedimelamine, tetramethylenedimelamine, hexamethylenedimelamine, 1,3-hexylenedimelamine, etc. These (poly)phosphates may be used alone or in combination of two or more.

Among the above phosphorus-based flame retardants, a salt of (poly)phosphoric acid and a nitrogen compound (hereinafter also referred to as "compound (b1)") is preferred. Compound (b1) is an intumescent flame retardant, and forms a surface expansion layer (intemescent) which is a foamed char when the resin composition is burned. The formation of the surface expansion layer suppresses the diffusion and heat transfer of decomposition products, and excellent flame retardancy is exhibited.
Examples of the nitrogen compound in the compound (b1) include ammonia, melamine, piperazine, and the other nitrogen compounds described above.

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

(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 perchloropentane dichloride, and potassium antimonate, with antimony trioxide and antimony pentoxide being particularly preferred.

(Intumescent flame retardant)
Intumescent flame retardants are flame retardants that suppress the combustion of materials by forming a surface expansion layer (intumescent) that prevents the diffusion of radiant heat from the combustion source and combustion gases and smoke from the burning material to the outside. Examples of intumescent flame retardants include salts of (poly)phosphoric acid and nitrogen compounds. 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.

(b) Flame retardant content
The content of the flame retardant in the laminate of the present invention is not particularly limited, but is preferably in the range of 1 to 30% by mass as the content in the thermoplastic resin composition (X). When the content is 1% by mass or more, good flame retardancy can be imparted to the laminate, and good flame shielding properties can be obtained. On the other hand, when the flame retardant is 30% by mass or less, the thermoplastic resin can be contained in a sufficient content ratio, so that the molding processability becomes better. From the above viewpoints, the content of the flame retardant in the thermoplastic resin composition (X) is more preferably in the range of 1 to 25% by mass, and even more preferably in the range of 3 to 20% by mass.
In addition, it is also preferable from the viewpoint of improving flame-proofing properties to contain a flame retardant in the thermoplastic resin layer (B). The content in the thermoplastic resin layer (B) is preferably in the range of 1 to 30% by mass. When it is 1% by mass or more, good flame retardancy can be imparted to the laminate, and good flame-proofing properties can be obtained. On the other hand, when the flame retardant is 30% by mass or less, the thermoplastic resin can be contained in a sufficient content ratio, so that the molding processability becomes better. From the above viewpoints, the content of the flame retardant in the thermoplastic resin layer (B) is more preferably in the range of 1 to 25% by mass, and even more preferably in the range of 3 to 20% by mass.

<(c) Dispersant>
The thermoplastic resin composition (X) according to the present invention preferably further contains a dispersant.
The (c) dispersant is not particularly limited as long as it can disperse the (b) flame retardant in the (a) thermoplastic resin, but a polymer dispersant can be preferably used in terms of compatibility with the (a) thermoplastic resin. Preferably, a polymer dispersant capable of dispersing the (b) flame retardant in the (a-1) polypropylene resin can be preferably used. As the polymer dispersant, a polymer dispersant having a functional group is preferred, and from the viewpoint of dispersion stability, a polymer dispersant having a functional group such as a carboxyl group, a phosphoric acid group, a sulfonic acid group, a primary, secondary or tertiary amino group, a quaternary ammonium base, a group derived from a nitrogen-containing heterocycle such as pyridine, pyrimidine or pyrazine is preferred.
In the present invention, a polymer 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 such a 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 "copolymer of α-olefin and unsaturated carboxylic acid" according to the present invention (hereinafter referred to as "copolymer (c1)"), the proportion of α-olefin units in the total of 100 mol % of α-olefin units and unsaturated carboxylic acid units is preferably 20 mol % or more and 80 mol % or less.
In the copolymer (c1), the ratio of the α-olefin units to the total amount of the α-olefin units and the unsaturated carboxylic acid units is more preferably 30 mol % or more, and more preferably 70 mol % or less. If the ratio of the α-olefins is equal to or more than the lower limit, (a) the compatibility with the polyolefin resin is better, and if it is equal to or less than the upper limit, (b) the compatibility with the non-halogen flame retardant is better.

In the copolymer (c1), the α-olefin is preferably an α-olefin having 5 or more carbon atoms, and more preferably an α-olefin having 10 to 80 carbon atoms. If the α-olefin has 5 or more carbon atoms, it tends to have better compatibility with the thermoplastic resin (a), and if it has 80 or less carbon atoms, it is advantageous in terms of raw material costs. From the above viewpoints, it is even more preferable that the α-olefin has 12 to 70 carbon atoms, and particularly preferably 18 to 60 carbon atoms.

In the copolymer (c1), examples of the unsaturated carboxylic acid include (meth)acrylic acid, maleic acid, methylmaleic acid, fumaric acid, methylfumaric acid, tetrahydrophthalic acid, itaconic acid, citraconic acid, crotonic acid, isocrotonic acid, glutaconic acid, norbornane-5-ene-2,3-dicarboxylic acid, and esters, anhydrides, imides, etc. of these unsaturated carboxylic acids. Note that "(meth)acrylic acid" refers to acrylic acid or methacrylic acid.
Specific examples of the ester, anhydride or imide of an unsaturated carboxylic acid include (meth)acrylic acid esters such as methyl (meth)acrylate, ethyl (meth)acrylate, butyl (meth)acrylate, 2-ethylhexyl (meth)acrylate, and glycidyl (meth)acrylate; dicarboxylic acid anhydrides such as maleic anhydride, itaconic anhydride, citraconic anhydride, and 5-norbornene-2,3-dicarboxylic acid anhydride; maleimide compounds such as maleimide, N-ethylmaleimide, and N-phenylmaleimide. These may be used alone or in combination of two or more.
Among the above, esters and dicarboxylic anhydrides are preferred from the viewpoint of copolymerization reactivity, and among these, dicarboxylic anhydrides are preferred, with maleic anhydride being particularly preferred, from the viewpoint of compatibility with phosphorus-based flame retardants that are suitable as flame retardants.

The weight average molecular weight of the copolymer (c1) is preferably 2,000 or more, more preferably 3,000 or more, and is preferably 50,000 or less, more preferably 30,000 or less. When the weight average molecular weight of the copolymer (c1) is within the above range, the dispersibility of the flame retardant (b) is more excellent.
The weight average molecular weight of the copolymer (c1) is a value calculated as standard polystyrene by dissolving the copolymer (c1) in tetrahydrofuran (THF) and measuring the result by gel permeation chromatography.

Commercially available copolymers (c1) include Ricorb CE2 (Clariant Japan Co., Ltd.) and Diacalna 30M (Mitsubishi Chemical Co., Ltd.).

The content of the dispersant (c) relative to 100 parts by mass of the flame retardant (b) in the thermoplastic resin composition (X) according to the present invention is in the range of more than 0 and not more than 25 parts by mass, and preferably in the range of 0.01 to 10 parts by mass.
According to the study by the inventors, the flame retardant is uniformly dispersed in the inorganic fibers constituting the laminate with a thermoplastic resin as a matrix resin, and the flame-resistant properties of the laminate can be significantly improved. Although the detailed mechanism is unclear, the inventors speculate as follows. That is, when the flame retardant is uniformly dispersed in the resin between the inorganic fibers, the char formed by the flame retardant coming into contact with the flame is fixed in the gaps between the inorganic fibers. Furthermore, the size of the char formed by expansion upon contact with the flame is restricted by the gaps between the inorganic fibers, and the size of the char formed becomes uniform. It is believed that the combination of the fixing effect of the char by the inorganic fibers and the uniformity of the char size results in the formation of dense char, and the flame-resistant properties of the laminate are significantly improved. Based on these findings, the inventors have found that by setting the ratio of the content of the dispersant to the flame retardant to a specific range, the flame retardant can be controlled to be uniformly present in the resin between the inorganic fibers, and the flame-resistant properties of the laminate can be significantly improved.
For the above reasons, when the content of the (c) dispersant is more than 0, the dispersibility of the (b) flame retardant is sufficient, and sufficient flame-shielding properties can be imparted to the laminate. On the other hand, when the content is 25 parts by mass or less, the physical properties of the laminate are sufficient. From the same viewpoint, the content of the (c) dispersant is preferably 0.01 parts by mass or more, more preferably 0.1 parts by mass or more, even more preferably 1 part by mass or more, and particularly preferably 2 parts by mass or more. On the other hand, the upper limit is more preferably 20 parts by mass or less, even more preferably 15 parts by mass or less, even more preferably 10 parts by mass or less, even more preferably 5 parts by mass or less, and particularly preferably 3 parts by mass or less.

In addition, the ratio of the (c) dispersant to the total of 100 parts by mass of the (a) thermoplastic resin and the (b) non-halogen flame retardant is preferably 0.01 parts by mass or more, more preferably 0.05 parts by mass or more, and even more preferably 0.1 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, even more preferably 2.0 parts by mass or less, more preferably 1.5 parts by mass or less, and even more preferably 1.0 parts by mass or less. If the ratio of the (c) dispersant is equal to or greater than the lower limit, the (b) non-halogen flame retardant is better dispersed, and the flame retardant properties and physical properties of the obtained laminate and the appearance of the obtained molded product are better. If the ratio of the (c) dispersant is equal to or less than the upper limit, the influence of the (c) dispersant on the flame retardant properties of the laminate can be further suppressed. In particular, the ratio of the (c) dispersant to the total of 100 parts by mass of the polyolefin resin and the (b) flame retardant is preferably 0.01 parts by mass or more, more preferably 0.05 parts by mass or more, and even more preferably 0.1 parts by mass or more. On the other hand, 10 parts by mass or less is preferable, 5.0 parts by mass or less is more preferable, 2.0 parts by mass or less is even more preferable, 1.5 parts by mass or less is even more preferable, and 1.0 parts by mass or less is even more preferable.

For the (Y) inorganic fibers described in detail below, the ratio of the (c) dispersant to 100 parts by mass of the (Y) inorganic fibers is preferably 0.01 parts by mass or more, more preferably 0.05 parts by mass or more, and even more preferably 0.1 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. If the ratio of the (c) dispersant is equal to or greater than the lower limit, the flame-resistant properties and physical properties of the resulting laminate and the appearance of the resulting molded product are improved. If the ratio of the (c) dispersant is equal to or less than the upper limit, the effect of the (c) dispersant on the flame-resistant properties of the laminate can be further suppressed.

When the thermoplastic resin layer (B) contains a flame retardant, it is preferable from the viewpoint of improving flame-shielding properties that the thermoplastic resin layer (B) further contains a dispersant. The content of the dispersant (c) per 100 parts by mass of the flame retardant (b) in the thermoplastic resin layer (B) according to the present invention is preferably in the range of more than 0 and not more than 25 parts by mass, and more preferably in the range of 0.01 to 10 parts by mass.

<(Y) Inorganic Fiber>
The laminate of the present invention has a layer (A) in which the thermoplastic resin composition (X) and the inorganic fibers (Y) are integrated together. Here, the integrated layer refers to a layer in which the thermoplastic resin composition (X) permeates the inorganic fibers (Y) and the inorganic fibers (Y) are thoroughly integrated together.
As the inorganic fiber (Y), various fibers can be used, for example, glass fiber, rock wool, metal oxide fibers such as alumina fiber and silica alumina fiber, potassium titanate fiber, calcium silicate (wollastonite) fiber, ceramic fibers such as ceramic fiber, carbon fiber, metal fiber, etc. These inorganic fibers may be used alone or in combination of two or more.
Of the above inorganic fibers, at least one selected from glass fibers and alumina fibers is preferred from the viewpoints of flame resistance and processability.
The (Y) inorganic fiber may contain two or more inorganic fibers having different melting temperatures. As a combination of two or more inorganic fibers having different melting temperatures, at least one of the fibers is preferably glass fiber, and the other one or more is preferably one or more inorganic fibers selected from the group consisting of alumina fiber, silica fiber, alkaline earth silicate fiber (biosoluble), and carbon fiber. By containing two or more inorganic fibers having different melting temperatures, it is possible to effectively prevent the deterioration of the flame-shielding function.
The inorganic fibers used in the present invention may be used in combination with a sizing agent or a surface treatment agent, such as compounds having a functional group, such as epoxy compounds, silane compounds, and titanate compounds.

The inorganic fibers preferably have an average fiber diameter of 3 to 25 μm, and an average fiber length of 0.1 mm or more, more preferably 1 mm or more, and even more preferably 5 mm or more.
As for the average fiber diameter and the average fiber length, the preferred ranges vary depending on the type of inorganic material constituting the inorganic fibers, and specific preferred ranges will be described later.
The fiber diameter can be measured using a scanning electron microscope or the like, and the average fiber diameter can be obtained by, for example, measuring the fiber diameters of 10 randomly selected fibers and calculating the average value. The fiber length can be measured using a ruler, calipers, or the like from an image enlarged by a microscope or the like as necessary, and the average fiber length can be obtained by, for example, measuring the fiber lengths of 10 randomly selected fibers and calculating the average value.

The content of inorganic fibers in the laminate of the present invention is 1 to 80% by mass. When the content of inorganic fibers is 1% by mass or more, the strength, rigidity, and impact resistance of the laminate are sufficient, and when it is 80% by mass or less, it is preferable in terms of manufacturing and processing of the laminate. In addition, when the content of inorganic fibers is 80% by mass or less, the specific gravity of the laminate is light, and the weight reduction effect as a metal substitute is remarkable.
From the above viewpoints, the content of the (Y) inorganic fiber in the laminate is more preferably from 3 to 60 mass %, further preferably from 10 to 50 mass %, and particularly preferably from 30 to 45 mass %.

(Glass fiber)
One of the inorganic fibers (Y) suitable for the laminate of the present invention is glass fiber. The glass fiber may be, for example, a long fiber having an average fiber length of 30 mm or more, or a fiber having a short average fiber length (chopped strand), but it is preferable to use glass fiber having a long average fiber length from the viewpoints of flame retardancy, rigidity, impact resistance, etc.
More specifically, the average fiber length is preferably 5 mm or more. When the average fiber length is 5 mm or more, the strength and impact resistance of the laminate are good. From the above viewpoints, the average fiber length of the glass fiber is preferably 5 mm or more, and more preferably 30 mm or more.
There is no particular upper limit to the average fiber length of the glass fibers, and when using pellets produced by the pultrusion method using glass fibers, the length of the pellets is the fiber length of the glass fibers, which is a maximum of about 20 mm. In addition, in a swirl mat system using long glass fibers, the length of the glass fibers in the roving used for production is the maximum fiber length, which can be as long as 17,000 m (17 km), but when cut to fit the size of the laminate, the cut length is the maximum fiber length.

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 viewpoints, the average fiber diameter of the glass fibers is more preferably in the range of 10 to 15 μm.
The average fiber diameter and average fiber length of the glass fibers can be measured by the above-mentioned method.

There are no particular limitations on the material of the glass fiber used in the present invention, and it may be any of alkali-free glass, low-alkali glass, and alkali-containing glass, and any of the various compositions that have been used conventionally as glass fibers can be used.

(Alumina fiber)
One of the inorganic fibers (Y) suitable for the laminate of the present invention is alumina fiber. Alumina fiber is usually a fiber made of alumina and silica, and in the laminate of the present invention, the alumina/silica composition ratio (mass ratio) of the alumina fiber is preferably in the range of 65/35 to 98/2, which is called a mullite composition, or a high alumina composition, more preferably in the range of 70/30 to 95/5, and particularly preferably in the range of 70/30 to 74/26.

The average fiber diameter of the alumina fibers is preferably in the range of 3 to 25 μm, and it is preferable that the alumina fibers are substantially free of fibers with a fiber diameter of 3 μm or less. Here, "substantially free of fibers with a fiber diameter of 3 μm or less" means that the amount of fibers with a fiber diameter of 3 μm or less is 0.1 mass % or less of the total inorganic fiber mass.
The average fiber diameter of the alumina fibers is more preferably 5 to 8 μm. If the average fiber diameter of the inorganic fibers is too large, the repulsive force and toughness of the mat-like inorganic fiber assembly layer will decrease, while if the average fiber diameter is too small, the amount of dust suspended in the air will increase, and the probability of containing inorganic fibers having a fiber diameter of 3 μm or less will increase.
The alumina fibers have an average fiber length of preferably 5 mm or more, more preferably 30 mm or more, and even more preferably 50 mm or more. Also, the average fiber length and average fiber diameter of the alumina fibers are preferably 3.0× ¹⁰ mm or less, and more preferably 1.0× ¹⁰ mm or less. When the average fiber length and average fiber diameter of the alumina fibers are within these ranges, the strength and impact resistance of the laminate are good.

(Carbon fiber)
The suitable range for carbon fiber is similar to that for glass fiber.

<Optionally Added Ingredients>
In addition to the above-mentioned components, any additive components may be blended into the laminate of the present invention for the purpose of further improving the effects of the present invention or imparting other effects, within a range that does not significantly impair the effects of the present invention.
Specific examples of the additives include colorants such as pigments, light stabilizers such as hindered amines, ultraviolet absorbers such as benzotriazoles, nucleating agents such as sorbitols, antioxidants such as phenols and phosphorus, antistatic agents such as nonionic surfactants, neutralizing agents such as inorganic compounds, antibacterial and antifungal agents such as thiazoles, flame retardant assistants such as lignophenols, plasticizers, dispersants such as organic metal salts, lubricants such as fatty acid amides, metal deactivators such as nitrogen compounds, polyolefin resins other than the polypropylene resins, thermoplastic resins such as polyamide resins and polyester resins, and elastomers (rubber components) such as olefin elastomers and styrene elastomers.
These optional components may be used in combination of two or more kinds.

Colorants such as inorganic or organic pigments are effective in imparting or improving the colored appearance, appearance, texture, commercial value, weather resistance, durability, etc. of polypropylene resin compositions and molded articles thereof.
Specific examples of inorganic pigments include carbon black such as furnace carbon and ketjen carbon; titanium oxide; iron oxide (e.g., red iron oxide); chromic acid (e.g., yellow lead); molybdic acid; selenide sulfide; and ferrocyanide. Specific examples of organic pigments include azo pigments such as sparingly soluble azo lake, soluble azo lake, and insoluble azo chelate; condensed azo chelate; and other azo chelates; phthalocyanine pigments such as phthalocyanine blue and phthalocyanine green; threne pigments such as anthraquinone, perinone, perylene, and thioindigo; dye lake; quinacridone; dioxazine; and isoindolinone. In order to achieve a metallic or pearlescent look, aluminum flakes and pearl pigments can be added. Dyes can also be added.

Light stabilizers and ultraviolet absorbers, for example, hindered amine compounds, benzotriazoles, benzophenones, and salicylates, are effective in imparting or improving the weather resistance, durability, and the like of polypropylene resin compositions and molded articles thereof, and are effective in further improving weather discoloration resistance.
Specific examples of the hindered amine compound include a condensation product 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-butane tetracarboxylate; tetrakis(1,2,2,6,6-pentamethyl-4-piperidyl)1,2,3,4-butane tetracarboxylate; bis(1,2,2,6,6-pentamethoxy) 2-(2'-hydroxy-3'-t-butyl-5'-methylphenyl)-5-chlorobenzotriazole;2-(2'-hydroxy-3'-t-butyl-5'-methylphenyl)-5-chlorobenzotriazole;2-hydroxy-4-methoxybenzophenone;2-hydroxy-4-n-octoxybenzophenone; and the like. Examples of the salicylate-based compounds 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 light stabilizer and the ultraviolet absorber in combination is preferable because it has a large effect of improving weather resistance, durability, weather discoloration resistance, and the like.

As the antioxidant, for example, a phenol-based, phosphorus-based or sulfur-based antioxidant is effective in imparting or improving heat resistance, processing stability, heat aging resistance, etc. to a polypropylene resin composition and a molded article thereof.
Furthermore, antistatic agents such as nonionic and cationic antistatic agents are effective in imparting and improving antistatic properties to polypropylene resin compositions and molded articles thereof.

Examples of olefin-based elastomers include ethylene-α-olefin copolymer elastomers such as ethylene-propylene copolymer elastomer (EPR), ethylene-butene copolymer elastomer (EBR), ethylene-hexene copolymer elastomer (EHR), and ethylene-octene copolymer elastomer (EOR); ethylene-α-olefin-diene terpolymer elastomers such as ethylene-propylene-ethylidenenorbornene copolymer, ethylene-propylene-butadiene copolymer, and ethylene-propylene-isoprene copolymer; and styrene-butadiene-styrene triblock copolymer elastomer (SBS).
Examples of the styrene-based elastomer include styrene-based elastomers such as styrene-isoprene-styrene triblock copolymer elastomer (SIS), styrene-ethylene-butylene copolymer elastomer (SEB), 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 elastomer (SEPS), styrene-ethylene-ethylene-propylene-styrene copolymer elastomer (SEEPS), styrene-butadiene-butylene-styrene copolymer elastomer (SBBS), partially hydrogenated styrene-isoprene-styrene copolymer elastomer, and partially hydrogenated styrene-isoprene-butadiene-styrene copolymer elastomer, as well as hydrogenated polymer-based elastomers such as ethylene-ethylene-butylene-ethylene copolymer elastomer (CEBC).
Among these, the use of an ethylene-octene copolymer elastomer (EOR) and/or an ethylene-butene copolymer elastomer (EBR) is preferred since it is easy to impart appropriate flexibility and the like to the polypropylene resin composition of the present invention and a molded article thereof, and they tend to have excellent impact resistance.

<Method for producing thermoplastic resin composition (X)>
As described above, the thermoplastic resin composition (X) according to the present invention contains (a) a thermoplastic resin, a modified polyolefin resin added as needed, (b) a halogen-free flame retardant, and (c) a dispersant added as needed. In addition, optional additives may be further blended. In the thermoplastic resin composition (X), when the thermoplastic resin (a) is a polypropylene resin (a-1), it may be particularly called a polypropylene resin composition (hereinafter, sometimes referred to as a "PP composition").
The thermoplastic resin composition (X) or the PP composition can be produced by a conventionally known method, and can be produced by blending, mixing, and melt-kneading the above-mentioned components.
The mixing is carried out using a mixer such as a tumbler, a V blender, or a ribbon blender, and the melt kneading is carried out using equipment such as a single-screw extruder, a twin-screw extruder, a Banbury mixer, a roll mixer, a Brabender plastograph, or a kneader, and the materials are melt kneaded and granulated.

<Method of manufacturing laminate>
The laminate of the present invention is not particularly limited in the manufacturing method, but is preferably manufactured by impregnating a mat made of inorganic fibers (Y) (hereinafter sometimes referred to as "inorganic fiber mat (Y)") with the thermoplastic resin composition (X) or the PP composition. Examples of the impregnation method include a method of applying the thermoplastic composition (X) or the PP composition to the inorganic fiber mat (Y), and a method of preparing a sheet of the thermoplastic resin composition (X) or the PP composition (hereinafter sometimes referred to as "thermoplastic resin sheet" or "PP sheet"), laminating the thermoplastic resin sheet or the PP sheet on the inorganic fiber mat (Y), and heating and melting the sheet to impregnate the inorganic fiber mat (Y).
In the present invention, from the viewpoint of impregnation of the resin of the laminate into the fibers, a method of laminating a thermoplastic resin sheet or a PP sheet on an inorganic fiber mat (Y) and heating and melting it is preferred. In particular, the inorganic fiber mat is laminated between two thermoplastic resin sheets or PP sheets, and then the laminate is heated and pressed, and then cooled and solidified to obtain the laminate.
The thickness of the thermoplastic resin sheet or PP sheet is not particularly limited as long as it allows good impregnation of the fiber mat.

(Inorganic fiber mat (Y))
The form of the inorganic fibers used in the method for producing a laminate is not particularly limited, and various forms can be used, but it is preferable that the inorganic fibers are formed into a mat or sheet shape.
More specifically, a mat formed from glass fibers (hereinafter referred to as a "glass fiber mat") and a mat formed from metal oxide fibers such as alumina fibers (hereinafter referred to as a "metal oxide mat") are preferred.

The basis weight (mass per unit area) of the inorganic fiber mat is not particularly limited and is appropriately determined depending on the application, but is preferably 300 g/m ² or more, more preferably more than 800 g/m ² , and more preferably more than 1500 g/m ^2. The basis weight of the inorganic fiber mat is not particularly limited, but is preferably 5000 g/m ² or less, more preferably 4500 g/m ² or less, even more preferably 4000 g/m ² or less, and particularly preferably 3500 g/m ² or less.
The thickness of the inorganic fiber mat according to the present invention is not particularly limited, but is preferably 4 mm or more, more preferably 5 mm or more, and even more preferably 6 mm or more. The thickness of the fiber mat is preferably 40 mm or less, more preferably 35 mm or less, and particularly preferably 30 mm or less.

The basis weight per unit area of the inorganic fiber mat can be set within the above range by adjusting the amount of fiber per unit area when the inorganic fiber aggregates that make up the inorganic fiber mat are stacked using a folding device. The inorganic fiber mat of the present invention may be composed of multiple inorganic fiber mats bonded together or may be composed of a single material, but is preferably composed of a single material in terms of handling properties and peel strength at the adhesive interface.

(fiberglass mat)
The form of the glass fiber mat used in the present invention may be a felt or blanket made of short fiber glass wool, a chopped strand mat made of continuous glass fiber, a swirl (spiral) mat of continuous glass fiber, a unidirectionally aligned mat, etc. Among these, the use of a glass fiber mat obtained by needle punching a swirl (spiral) mat of continuous glass fiber is particularly preferred because it provides excellent strength and impact resistance of the laminate.

(Metal oxide fiber mat)
The metal oxide fiber mat according to the present invention is a mat that is made of metal oxide fibers such as alumina fibers and that has been subjected to a needling treatment.

In the method of laminating a thermoplastic resin sheet or a PP sheet on an inorganic fiber mat and heating and melting the sheet, the heating temperature is preferably 170 to 300° C. When the heating temperature is 170° C. or higher, the fluidity of the polypropylene resin is sufficient, and the inorganic fiber mat can be sufficiently impregnated with the PP composition, resulting in a suitable resin-impregnated body. On the other hand, when the heating temperature is 300° C. or lower, the thermoplastic resin composition or the PP composition does not deteriorate.
Furthermore, the pressure applied is preferably 0.1 to 1 MPa. If the pressure applied is 0.1 MPa or more, the inorganic fiber mat can be sufficiently impregnated with the thermoplastic resin composition or the PP composition, and a suitable resin-impregnated body can be obtained. On the other hand, if the pressure applied is 1 MPa or less, the thermoplastic resin composition or the PP composition flows, and no burrs are generated.
The cooling temperature is not particularly limited as long as it is equal to or lower than the freezing point of the thermoplastic resin in the thermoplastic resin composition (X) or the PP composition, but if the cooling temperature is equal to or lower than 80° C., the resin-impregnated body obtained will not deform when it is taken out. From the above viewpoints, the cooling temperature is preferably from room temperature to 80° C.

The resin-impregnated body is finally produced into a laminate by a method such as press molding in a mold equipped with a heating device, or by lamination processing in which heat and pressure are applied between two pairs of rollers equipped with a heating device. In particular, lamination processing is preferable because it allows for continuous production and has good productivity.

<Thickness of Laminate>
The thickness of the laminate of the present invention is usually 1 to 10 mm, preferably 2 to 5 mm. When the thickness of the laminate is 1 mm or more, the laminate can be easily produced, while when the thickness of the laminate is 10 mm or less, long-term preheating is not required when the laminate is processed by stamping molding or the like, and good moldability can be obtained.
The thickness of the layer (A) of the present invention is not particularly limited, but is preferably 40% or more of the total thickness of the laminate from the viewpoint of improving mechanical strength and moldability. On the other hand, from the viewpoint of improving flame-proofing and heat insulation, it is preferably 95% or less of the thickness of the laminate. From the same viewpoint, the thickness of the layer (A) is more preferably 45% or more of the total thickness of the laminate, even more preferably 55% or more, particularly preferably 60% or more, more preferably 90% or less, even more preferably 85% or less, and particularly preferably 80% or less. When the laminate has a plurality of layers (A), the total thickness may be within the above range.
The thickness of the layer (B) of the present invention is not particularly limited, but is preferably 5% or more of the total thickness of the laminate from the viewpoint of improving flame-proofing and heat insulation. On the other hand, from the viewpoint of moldability, it is preferably 50% or less of the thickness of the laminate. From the same viewpoint, the thickness of the layer (B) is more preferably 10% or more of the total thickness of the laminate, even more preferably 15% or more, particularly preferably 20% or more, more preferably 45% or less, and even more preferably 40% or less. When the laminate has a plurality of layers (A), the total thickness may be within the above range.

<Molded body>
The laminate of the present invention can be molded into a desired shape by stamping in a conventional manner, to obtain a molded article made of the laminate of the present invention.

(Application)
Examples of applications of the laminate of the present invention include various parts in the industrial field, such as automobile parts and electrical and electronic equipment parts. In particular, since it has excellent strength, rigidity, and electrical conductivity, as well as excellent processability, it can be suitably used in applications where these performances are required in a balanced manner and at a higher level, such as various housings and cases, such as battery cases.

[Structure]
Examples of structures made of the molded article of the present invention include battery housings and battery cells.
The structure in the present invention is preferably a battery, and the battery is not particularly limited. For example, 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 can be mentioned. Among these, lithium ion batteries are preferable, and the battery housing of the present invention is particularly suitable for use in suppressing thermal runaway of lithium ion batteries. That is, the battery housing of the present invention is preferably a battery housing for lithium ion batteries.

[Electric Mobility]
In the present invention, electric mobility refers to transportation equipment such as vehicles, ships, and airplanes that run on electricity as an energy source. Note that vehicles include hybrid cars in addition to electric vehicles (EVs).
The above-described battery housing and battery structures having battery cells of the present invention are highly safe and extremely useful for electric mobility using battery modules with high energy density to extend driving distance.

The present invention will be described in detail below using examples, but the present invention is not limited to these examples.
(Evaluation method)
1. Evaluation of flame barrier properties For the laminates prepared in each Example and Comparative Example, a flame from a burner at 1200°C was applied from one surface, and after 15 minutes, the flame was evaluated based on whether it penetrated. The distance from the burner nozzle to the sample was 110 mm. The flame surface was set to 1200°C. The flame surface temperature was confirmed with a thermocouple thermometer.

2. Evaluation of flame resistance In the same manner as in the evaluation method of flame shielding, a flame from a burner at 1200°C was applied to one surface of the laminate, and the time (seconds) until the entire surface (back surface) opposite the flame-contact surface melted was measured. The longer the time, the higher the flame resistance can be evaluated. In addition, the time (seconds) until the combustion of the entire flame-contact surface was reduced was measured. The shorter the time, the higher the flame resistance can be evaluated.

3. Evaluation of smoke generation In the same manner as in the evaluation method of flame barrier properties, a flame from a burner at 1200°C was applied to one surface of the laminate, and the amount of smoke from the surface opposite to the flame-contact surface (reverse surface) was visually evaluated. A large amount of smoke was rated as large, a medium amount as medium, and a small amount as small.
In addition, the time (seconds) until smoke began to be emitted from the back surface and the time (seconds) until smoke was confirmed to be emitted from the entire back surface were measured. The longer the time for either, the better the result.

4. Evaluation of heat insulation In the flame-shielding evaluation described in 1 above, the temperature of the surface (back surface) opposite to the surface exposed to the burner flame of the test piece was measured with a non-contact radiation thermometer (FT-H50K manufactured by Keyence Corporation). The measurement area was φ35 mm. The center of the measurement area was visually set to be immediately above the position of the burner flame. Table 1 shows the maximum temperature (°C) reached on the back surface until 600 seconds had elapsed.

(Materials used)
1. Polypropylene resin (component a)
(a1) "Novatec PP SA06GA" (melt flow rate: 60 g/10 min) manufactured by Japan Polypropylene Corporation was used.
(a2) "Novatec PP EC9GD" (melt flow rate: 0.5 g/10 min) manufactured by Japan Polypropylene Corporation was used.

2. Flame retardant (component b)
Phosphorus-based flame retardant composition (ADEKA CORPORATION, Adeka STAB FP-2500S, containing 50 to 60 mass% piperazine pyrophosphate, 35 to 45 mass% melamine pyrophosphate, and 3 to 6 mass% zinc oxide based on the total mass of the phosphorus-based flame retardant composition)

3. Dispersant (component c)
α-Olefin/maleic anhydride copolymer (Mitsubishi Chemical Corporation, Diacalna 30M, weight average molecular weight 7,800).

4. Glass fiber mat (Y component)
A glass fiber mat was used which was needle-punched from a swirl mat (basis weight 880 g/m ² ) made from continuous glass fibers (fiber diameter 23 μm) of roving.

Preparation Example 1 (Preparation of Thermoplastic Resin Composition (X))
68% by mass of the above component a1, 30% by mass of component b, and 2% by mass of component c were mixed and melt-kneaded (230° C.) to prepare pellets of a thermoplastic resin composition (X).

Preparation Example 2 (Preparation of resin composition for forming thermoplastic resin layer (B))
68% by mass of the component a2, 30% by mass of the component b, and 2% by mass of the component c were mixed and melt-kneaded (230° C.) to prepare pellets of a resin composition for forming a thermoplastic resin layer (B).

Preparation Example 3
Resin pellets were prepared in the same manner as in Preparation Example 1, except that the components b and c were not blended and the component a1 was 100 mass %.

Example 1
The method for producing the laminate of Example 1 will be described below with reference to Fig. 4. Fig. 4 shows the layer structure before the glass fiber mat is impregnated with the thermoplastic resin composition. Fig. 5 shows the layer structure after impregnation.
The pellets of the thermoplastic resin composition (X) granulated in Preparation Example 1 were put into an extruder, melted, and extruded into a sheet, and the extruded sheet-like thermoplastic resin composition (X) (hereinafter referred to as "sheet X"; 21 in FIG. 4) was sandwiched and laminated with a glass fiber mat 22 from both sides. Next, a sheet (hereinafter referred to as "sheet Y"; 11 in FIG. 4) formed from the thermoplastic resin composition prepared in Preparation Example 2 was laminated on one side (upper side in FIG. 4), and sheet X (13 in FIG. 4) was laminated on the other side (lower side in FIG. 4), and heated and pressed at 230° C. for 4 minutes while applying a pressure of 0.3 MPa using a laminator, and then cooled and solidified to obtain a laminate (thickness; 2.5 mm) (see FIG. 4). The sheet X was impregnated into the glass mat fiber, and a laminate was obtained in which a thermoplastic resin layer (B) (11 in FIG. 5) was laminated on one surface of the integrated glass fiber resin-impregnated layer (layer (A), 12 in FIG. 5) as shown in FIG. 5. The obtained laminate was cut, and the cross section was observed under an optical microscope, revealing that the layer (A) had a thickness of 1.9 mm, the layer (B) had a thickness of 0.6 mm, and the thickness of the layer (B) was 24% of the total thickness of the laminate.
In Example 1, the glass fiber resin-impregnated layer (layer (A)) (12 in FIG. 5) in FIG. 5 was used as the flame-contact layer, and the thermoplastic resin layer (B) (11 in FIG. 5) was used as the backside layer, and evaluation was performed by the above method. The results are shown in Table 2.

Example 2
In Example 1, the thermoplastic resin layer (B) (11 in FIG. 5) shown in FIG. 5 was used as the flame contact layer, and the glass fiber resin impregnated layer (layer (A)) (12 in FIG. 5) was used as the back surface layer, and evaluation was performed in the same manner as in Example 1. The results are shown in Table 2.

Example 3
A laminate was obtained in the same manner as in Example 1, except that a sheet Y was laminated on both sides of a laminate in which glass fiber mats 22 were sandwiched and laminated on both sides of a sheet X (see Figs. 6 and 7). The sheet X was impregnated into the glass mat fibers, and a laminate was obtained in which a thermoplastic resin layer (B) was laminated on both surfaces of an integrated glass fiber resin-impregnated layer (layer (A)) as shown in Fig. 7. The results of evaluation in the same manner as in Example 1 are shown in Table 2.

Comparative Example 1
A laminate was obtained in the same manner as in Example 1, except that the PP resin prepared in Preparation Example 3 was used instead of the thermoplastic resin X in Example 1, that glass fiber mats 22 were sandwiched and laminated on both sides of a resin sheet (sheet Z) formed from the PP resin prepared in Preparation Example 3, and that sheets Z were laminated on both sides of the glass fiber mats 22. The evaluation results are shown in Table 2.

As shown in Examples 1 to 3, the laminate of the present invention has excellent flame-proofing properties, and even after 15 minutes, the flame was blocked and did not spread to the back side. Regarding heat insulation properties, the back side temperature was suppressed between 397°C and 498°C.
In contrast, the flame penetrated to the back surface in about 140 seconds in Comparative Example 1. In addition, since the flame penetrated to the back surface in Comparative Example 1, the flame resistance could not be evaluated.

As described above, the laminate of the present invention has excellent flame shielding properties, flame resistance, smoke suppression, and heat insulation properties, and is therefore useful as a material for various industrial parts that require high safety, such as aircraft, ships, automobile parts, electrical and electronic equipment parts, building materials, etc. In particular, it can be suitably used for various battery housings and cases that have traditionally been made of metal, and is expected to contribute to the safety of automobiles as well as improve energy efficiency and reduce _CO2 emissions by reducing weight.

10 Laminate 11 Layer (B)
12 Layer (A)
13 Layer (C)
21 Resin sheet (X)
22 Glass fiber mat

Claims (10)

A laminate comprising a layer (A) in which a thermoplastic resin composition (X) and inorganic fibers (Y) are integrated, and a thermoplastic resin layer (B),
The layer (B) is disposed so that one surface thereof is adjacent to the layer (A) and the other surface thereof serves as a surface layer;
The thermoplastic resin composition (X) contains a thermoplastic resin and a halogen-free flame retardant,
The thermoplastic resin layer (B) is a laminate containing a thermoplastic resin having a melt flow rate (MFR, 230° C., 2.16 kg load) of 0.05 to 30 g/10 min. The laminate according to claim 1, wherein the non-halogen flame retardant is a phosphorus-based flame retardant. The laminate according to claim 2, wherein the thermoplastic resin composition (X) further contains a dispersant. The laminate according to claim 3, wherein the dispersant is a copolymer of an α-olefin and an unsaturated carboxylic acid. The laminate according to claim 3, wherein the content of the dispersant per 100 parts by mass of the phosphorus-based flame retardant is more than 0 and not more than 25 parts by mass. The laminate according to claim 1, wherein the inorganic fibers (Y) have an average fiber length of 0.1 mm or more. The laminate according to claim 1, wherein the inorganic fiber (Y) is at least one selected from glass fibers, ceramic fibers, metal fibers, and metal oxide fibers. The laminate according to claim 1, wherein the thermoplastic resin constituting the thermoplastic resin composition (X) and the thermoplastic resin constituting the thermoplastic resin layer (B) are polypropylene-based resins, and the content of the polypropylene-based resin is 15 to 80% by mass relative to the total mass. The laminate according to claim 1, wherein the content of the non-halogen flame retardant is 1 to 30% by mass based on the total mass. A molded body obtained by stamping the laminate according to any one of claims 1 to 9.