Fiber-reinforced resin composite sheet, fiber-reinforced resin composite material and resin molding having the same

Abstract

To provide a fiber-reinforced resin composite sheet which has excellent flame retardancy, and has good moldability and sufficient tensile strength under high temperature condition.SOLUTION: A fiber-reinforced resin composite sheet includes a flame retardant resin film composed of a thermoplastic resin composition having a glass transition temperature Tg of 90°C or higher, and a plurality of reinforcement fibers in which a plurality of reinforcement fibers opened from a reinforcement fiber bundle are laminated on the flame-retardant resin film while being oriented in the same direction, wherein a combustibility classification of the flame-retardant resin film determined in UL94VTM combustion test according to ASTM D 4804 standard is VTM-0, a volume percentage content Vf of the reinforcement fiber is 30% or more and 65% or less, thickness of the fiber-reinforced resin composite sheet is 20 μm or more and 100 μm or less, and a combustibility classification of the fiber-reinforced resin composite sheet determined in UL94-5V combustion test according to ASTM D 5048 standard is 5V-A or 5V-B.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present invention relates to a fiber-reinforced resin composite sheet including a flame-retardant resin film and reinforcing fibers. [Background technology]

[0002] Fiber-reinforced resin composites are widely used materials, from components for sports and leisure to components for industrial applications such as automobiles and aircraft. Fiber-reinforced resin composites are manufactured using an intermediate material, i.e., prepreg, in which a resin matrix is ​​impregnated with a reinforcing material made of long fibers (continuous fibers) such as reinforcing fibers. Specifically, a molded product of fiber-reinforced resin composite can be obtained by stacking multiple prepregs and heating and curing, or heating and cooling to solidify.

[0003] Conventionally, in the production of fiber-reinforced resin composites, thermosetting resins have been widely used as resins for prepregs from the viewpoint of excellent strength and rigidity (see, for example, Patent Document 1). However, prepregs using thermosetting resins have problems in that they have low impact resistance and are difficult to process. In order to solve these problems, prepregs in which reinforcing fibers are impregnated with thermoplastic resins as the matrix resin have been widely developed. Such prepregs are easy to melt by heating and solidify by cooling, so they are excellent in operability during molding and processing of the prepregs, and are expected to have effects such as shortening production time, which also leads to cost reduction.

[0004] Recently, fiber-reinforced resin composites are also used as materials for housings and parts of smartphones, tablets, laptops, video cameras, mobile devices, and other electric or electronic devices. Housings and parts of electric or electronic devices may ignite and burn due to heat generated from inside the device or exposure to a high-temperature environment. In order to prevent such accidents, the prepreg material is required to have flame retardancy. Generally, thermosetting resins have excellent flame retardancy, but thermoplastic resins have poor flame retardancy, and there are few thermoplastic resins that have sufficient flame retardancy by themselves without adding a flame retardant (see, for example, Patent Document 2). Therefore, when manufacturing fiber-reinforced resin composites that require flame retardancy, thermosetting resins are mainly used as the matrix resin.

[0005] However, depending on the type of molded product, for example, the type of housing or parts of an electrical or electronic device, good moldability may be required for the fiber reinforced resin composite material (hereinafter also referred to as "fiber reinforced resin composite sheet") in order to increase the degree of freedom in shape. On the other hand, a fiber reinforced resin composite sheet using a thermoplastic resin as the matrix resin has excellent moldability compared to a fiber reinforced resin composite sheet using a thermosetting resin, but has a problem of inferior strength. Depending on the type of housing or parts of an electrical or electronic device as described above, strength, for example tensile strength, may also be required. [Prior art documents] [Patent documents]

[0006] [Patent Document 1] Japanese Patent Application Publication No. 8-118381 [Patent Document 2] JP 2005-239939 A Summary of the Invention

[0007] Therefore, an object of the present invention is to provide a fiber-reinforced resin composite sheet having excellent flame retardancy, good moldability, and sufficient tensile strength under high temperature conditions.

[0008] A fiber-reinforced resin composite sheet according to a first aspect of the present invention is a fiber-reinforced resin composite sheet including: a flame-retardant resin film made of a thermoplastic resin composition having a glass transition temperature Tg of 90° C. or higher; and a plurality of reinforcing fibers laminated on the flame-retardant resin film in a state in which the plurality of reinforcing fibers are spread from a reinforcing fiber bundle and oriented in the same direction; The flammability classification of the flame-retardant resin film is VTM-0 as determined in a UL94 VTM flammability test in accordance with the ASTM D4804 standard; The volume fraction Vf of the reinforcing fibers is 30% or more and 65% or less, The thickness of the fiber reinforced resin composite sheet is 20 μm or more and 100 μm or less, The fiber reinforced resin composite sheet has a flammability classification of 5V-A or 5V-B as determined in a UL94-5V flammability test in accordance with ASTM D5048 standard. [Brief description of the drawings]

[0009] [Figure 1] FIG. 1 is a diagram showing an example of a schematic configuration of a manufacturing apparatus for a fiber-reinforced resin composite sheet in this embodiment. [Diagram 2] FIG. 2 is a diagram showing an example of a method for cutting out chopped material from the fiber reinforced resin composite sheet in this embodiment. [Diagram 3] FIG. 3 is a diagram for explaining a method for producing a laminated chopped sheet, which is an example of the fiber reinforced resin composite material in this embodiment. [Figure 4] FIG. 4 is a cross-sectional view of a laminated chopped sheet, which is an example of the fiber reinforced resin composite material in this embodiment. [Diagram 5] FIG. 5 shows laser microscope images of the cross sections of test pieces of the fiber-reinforced resin composite sheets in Examples 2-1 and 2-2 and Comparative Examples 2-1 and 2-2. [Figure 6] FIG. 6 is an image showing the results of a supplemental flame retardancy test of test pieces of the fiber-reinforced resin composite sheets in Examples 2-1 and 2-2 and Comparative Examples 2-1 and 2-2. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0010] The higher the volume fraction Vf of the reinforcing fibers in the fiber-reinforced resin composite material, the greater the tensile strength of the fiber-reinforced resin composite material tends to be. However, when manufacturing a fiber-reinforced resin composite sheet, which is an intermediate material, simply increasing the amount of reinforcing fibers impregnated into the resin matrix will make the sheet thicker, and the moldability of the fiber-reinforced resin composite sheet will decrease. Furthermore, it is predicted that the structure of the reinforcing fibers and the value of the volume fraction Vf will also affect the flame retardancy of the fiber-reinforced resin composite sheet, etc. In this way, it is difficult to adjust the flame retardancy, moldability, and strength properties of a fiber-reinforced resin composite sheet using a thermoplastic resin so that they are all suitable.

[0011] Furthermore, when a thermoplastic resin is used as the matrix resin, polyamide 6 resin is often used from the viewpoints of excellent physical properties such as impact resistance, toughness, and flexibility, as well as from the viewpoints of cost and ease of handling. However, since polyamide 6 resin has a relatively low glass transition temperature Tg, a fiber-reinforced resin composite sheet manufactured using the polyamide 6 resin may lose strength under high temperature conditions. Therefore, polyamide 6 resin is not suitable as a material that may be exposed to heat from inside the housing or parts of an electric or electronic device.

[0012] Therefore, the present inventors have conducted intensive research into a fiber-reinforced resin composite sheet having excellent flame retardancy, good moldability, and sufficient tensile strength under high temperature conditions. As a result, the present invention has been arrived at. Specifically, a thermoplastic resin composition having predetermined characteristics is selected, a fiber-reinforced resin composite sheet having a predetermined structure is constructed, the type and amount of the flame retardant added optionally are appropriately set, and the volume fraction Vf of the reinforcing fiber is appropriately adjusted within a predetermined range, thereby providing the fiber-reinforced resin composite sheet as described above.

[0013] Hereinafter, the embodiments of the present invention will be described in detail. Note that the scope of the present invention is not limited to the embodiments described here, and various modifications can be made without departing from the spirit of the present invention.

[0014] <Fiber-reinforced resin composite sheet> The fiber-reinforced resin composite sheet in this embodiment includes a flame-retardant resin film and a plurality of reinforcing fibers laminated on the flame-retardant resin film. The plurality of reinforcing fibers are laminated on the flame-retardant resin film in a state in which the plurality of reinforcing fibers spread from a reinforcing fiber bundle are oriented in the same direction.

[0015] Here, throughout this specification, the term "reinforced fibers are laminated" used in the "flame-retardant resin film" also means "at least a part of the reinforcing fibers are fused to the flame-retardant resin film and laminated," "at least a part of the reinforcing fibers are attached to the flame-retardant resin film and laminated," "at least a part of the reinforcing fibers are pressed against the flame-retardant resin film and laminated," and "approximately half of each reinforcing fiber is impregnated from the surface of the flame-retardant resin film to the inside," depending on the physical properties and shape of the flame-retardant resin film, the type of treatment performed for lamination, and the conditions thereof. More specifically, heating, cooling and / or pressure treatment may be performed as necessary during "lamination."

[0016] First, each component included in the fiber reinforced resin composite sheet in this embodiment will be described.

[0017] [Flame-retardant resin film] The flame-retardant resin film is made of a thermoplastic resin composition having a glass transition temperature Tg of 90° C. or higher. When the thermoplastic resin contained in the thermoplastic resin composition has flame retardant properties, the thermoplastic resin composition may be made of a thermoplastic resin alone. Alternatively, when the thermoplastic resin contained in the thermoplastic resin composition does not have flame retardant properties, the thermoplastic resin composition contains a flame retardant. Furthermore, the thermoplastic resin composition may contain other additives other than the flame retardant as necessary. Each component contained in the thermoplastic resin composition will be described below.

[0018] (thermoplastic resin) The thermoplastic resin composition is not particularly limited as long as it has a glass transition temperature Tg of 90° C. or higher, and may be composed of a thermoplastic resin alone or may be a composition containing a thermoplastic resin and a flame retardant. Alternatively, a commercially available product may be used. Examples of types of thermoplastic resins include methacrylic resins such as polymethyl methacrylate resins, polystyrene resins, ABS resins, and AS resins, polyamide (PA) resins such as PA9T, polycarbonate (PC) resins, polyphenylene sulfide (PPS) resins, modified polyphenylene ether (PPE) resins, polyetherimide (PEI) resins, polysulfone (PSF) resins, polyethersulfone (PES) resins, polyarylate (PAR) resins, polyethernitrile (PEN) resins, polyetherketone (PEK) resins, polyetheretherketone (PEEK) resins, polyetherketoneketone (PEKK) resins, polyimide (PI) resins, polyamideimide (PAI) resins, fluorine (F) resins, liquid crystal polymer (LCP) resins such as liquid crystal polyester resins, or copolymer resins or modified resins thereof. In the thermoplastic resin composition, these thermoplastic resins may be contained alone or in combination.

[0019] Among these thermoplastic resins, it is preferable to use a highly heat-resistant plastic resin, so-called super engineering plastic, from the viewpoint of excellent properties such as heat resistance, flame retardancy, and strength. That is, the thermoplastic resin composition preferably contains one or more selected from polyphenylene sulfide (PPS) resin, polyether ether ketone (PEEK) resin, polyether ketone ketone (PEKK) resin, polyether imide (PEI) resin, polyether sulfone (PES) resin, and liquid crystal polymer (LCP) resin. Since these thermoplastic resins have excellent flame retardant properties, the thermoplastic resin composition may be composed of these thermoplastic resins alone. Specifically, if these resin films meet the conditions of the flammability classification described later and the fiber reinforced resin composite sheet manufactured using the resin film also meets the conditions of the flammability classification described later, a flame retardant may not be included. Furthermore, from the viewpoint of having a high continuous use temperature among these super engineering plastics, it is more preferable that the thermoplastic resin composition contains one or more selected from polyphenylene sulfide (PPS) resin, polyether ether ketone (PEEK) resin, and polyether ketone ketone (PEKK) resin. For example, the flame-retardant resin film made of the thermoplastic resin composition may be made of any one of polyphenylene sulfide (PPS) resin, polyether ether ketone (PEEK) resin, and polyether ketone ketone (PEKK) resin.

[0020] These super engineering plastics may be known commercially available products. Examples of commercially available polyphenylene sulfide (PPS) resins include "TORELINA (registered trademark)" manufactured by Toray Industries, Inc., "DURAFIDE (registered trademark)" manufactured by Polyplastics Co., Ltd., and "Ryton (registered trademark)" manufactured by Solvay. Examples of commercially available polyetheretherketone (PEEK) resins include "TORAY TPS (registered trademark) PEEK" manufactured by Toray Industries, Inc., "Vestakeep" manufactured by Daicel-Evonik Co., Ltd., and "PEEK Polymer" manufactured by Victrex. Examples of commercially available polyetherketoneketone (PEKK) resins include "Kepstan (registered trademark) PEKK" manufactured by Arkema. Examples of commercially available polyetherimide (PEI) resins include "Ultem (registered trademark)" manufactured by Sabic. Examples of commercially available polyethersulfone (PES) resins include "SumikaExcel PES" manufactured by Sumitomo Chemical Co., Ltd., "Mitsui PES (registered trademark)" manufactured by Mitsui Fine Chemicals, Inc., and "Ultrason (registered trademark) E" manufactured by BASF. Examples of commercially available liquid crystal polymer (LCP) resins include "SumikaSuper LCP" manufactured by Sumitomo Chemical Co., Ltd., "LAPEROS (registered trademark) LCP" manufactured by Polyplastics Co., Ltd., and "UENOLCP (registered trademark)" manufactured by Ueno Junyaku Co., Ltd.

[0021] Alternatively, the thermoplastic resin composition preferably contains a polycarbonate (PC) resin from the viewpoint of obtaining a fiber-reinforced resin composite sheet having excellent processability. When the thermoplastic resin composition contains a polycarbonate (PC) resin as a thermoplastic resin, the thermoplastic resin composition preferably further contains one or more flame retardants selected from a halogen-based flame retardant, a phosphorus-based flame retardant, a silicone-based flame retardant, and an inorganic flame retardant.

[0022] In this embodiment, since the glass transition temperature Tg of the thermoplastic resin composition constituting the flame-retardant resin film is 90° C. or higher, it is predicted that the fiber-reinforced resin composite sheet, etc. manufactured using the thermoplastic resin composition will not lose properties such as tensile strength or bending strength even under high temperature conditions. In contrast, for example, the glass transition temperature Tg of the polyamide 6 resin matrix, which is widely used as a resin matrix for prepregs, is about 50° C. (see Comparative Example 1-1 described later). Therefore, it is predicted that the fiber-reinforced resin composite sheet, etc. manufactured using polyamide 6 resin will lose properties such as strength under high temperature conditions.

[0023] (Flame retardant) The thermoplastic resin composition contains a flame retardant as necessary. In particular, when the thermoplastic resin contained in the thermoplastic resin composition does not have flame retardant properties, the thermoplastic resin composition contains a flame retardant as an essential component. Even when the thermoplastic resin contained in the thermoplastic resin composition has flame retardant properties, the thermoplastic resin composition may further contain a flame retardant from the viewpoint of improving the flame retardant properties.

[0024] The flame retardant is not particularly limited, but examples thereof include halogen-based flame retardants, phosphorus-based flame retardants, silicone-based flame retardants, inorganic flame retardants, other flame retardants, etc. Each of these will be described below.

[0025] Examples of halogen-based flame retardants include bromine-based flame retardants and chlorine-based flame retardants.

[0026] Examples of bromine-based flame retardants include decabromodiphenyl ether, tetrabromobisphenol A, its derivatives tetrabromobisphenol A carbonate oligomer, tetrabromobisphenol A epoxy oligomer, etc., polybenzene ring compound bis(pentabromophenyl)ethane, 1,2-bis(2,4,6-tribromophenoxy)ethane, etc., brominated polystyrene, brominated polystyrene, polybrominated styrene, etc., phthalic acid, ethylene bistetrabromophthalimide, etc., cyclic aliphatic hexabromocyclododecane, etc., or other hexabromobenzene, pentabromobenzyl acrylate, etc. Examples of chlorine-based flame retardants include chlorinated paraffin, dechlorane, chlorendic acid, chlorendic anhydride, etc.

[0027] Examples of phosphorus-based flame retardants include aromatic phosphate ester flame retardants, aromatic condensed phosphate ester flame retardants, halogen-containing phosphate ester flame retardants, and other phosphorus-based flame retardants.

[0028] Examples of aromatic phosphate ester flame retardants include triphenyl phosphate, cresyl phenyl phosphate, tricresyl phosphate, trixylyl phosphate, tris(t-butylated phenyl) phosphate, tris(i-propylated phenyl) phosphate, and 2-ethylhexyl diphenyl phosphate. Examples of aromatic condensed phosphate ester flame retardants include 1,3-phenylene bis(diphenyl phosphate) and 1,2-phenylene bis(dixylenyl phosphate). Examples of halogen-containing phosphate ester flame retardants include tris(dichloropropyl) phosphate, trischloroethyl phosphate, and 2,2-bis(dichloromethyl)trimethylene, bis(2-chloroethyl) phosphate. Examples of other phosphorus-based flame retardants include red phosphorus, phosphate ester amide, and ammonium polyphosphate.

[0029] Examples of silicone-based flame retardants include polydimethylsiloxane, polymethylethylsiloxane, polymethyloctylsiloxane, polymethylvinylsiloxane, polydimethylphenylsiloxane, polydiphenylsiloxane, polydimethyldiphenylsiloxane, and polymethyl(3,3,3-trifluoropropyl)siloxane.

[0030] Examples of inorganic flame retardants include antimony compounds such as antimony trioxide, antimony tetroxide, antimony pentoxide, and sodium antimonate; molybdenum compounds such as molybdenum oxide and ammonium molybdate; hydrated metal compounds such as aluminum hydroxide and magnesium hydroxide; nanofillers such as titanium oxide, montmorillonite, and silica; or zinc borate, zinc stannate, zinc sulfide, tin oxide, zirconium oxide, zeolite, and low-melting point glass.

[0031] Other flame retardants include, for example, melamine compounds such as melamine cyanurate and melamine sulfate, nitrogen compounds such as triazine compounds and guanidine compounds, organometallic compounds such as calcium perfluorobutanesulfonate, potassium perfluorobutanesulfonate, potassium diphenylsulfonate, potassium diphenylsulfone-3-sulfonate, and potassium p-toluenesulfonate, hindered amine compounds, and expandable graphite.

[0032] Among the above-mentioned flame retardants, halogen-based flame retardants, phosphorus-based flame retardants, hindered amine compounds, and antimony compounds have flame retardancy due to radical trapping action. In addition, hydrated metal compounds and expandable graphite have flame retardancy due to endothermic action. Phosphorus-based flame retardants, halogen-based flame retardants, nitrogen compounds, hydrated metal compounds, antimony compounds, and ammonium polyphosphate have flame retardancy due to oxygen blocking action or combustible gas dilution action. Silicone-based flame retardants, low-melting glass, hydrated metal compounds, red phosphorus, ammonium polyphosphate, expandable graphite, and organometallic compounds have flame retardancy due to heat insulation action. By combining flame retardants with different actions to have the desired flame retardancy, a thermoplastic resin composition having the desired flame retardancy can be obtained.

[0033] The flame retardant may be added in an appropriate amount to the thermoplastic resin composition so that the flame retardant resin film made of the thermoplastic resin composition is classified as VTM-0 in the flammability classification determined by the UL94VTM flammability test conforming to the ASTM D4804 standard. The UL94VTM flammability test conforming to the ASTM D4804 standard will be described in detail in the examples below. Furthermore, the flame retardant needs to be added in an amount adjusted while taking into account the volume fraction Vf of the reinforcing fibers so that the fiber-reinforced resin composite sheet produced using the flame retardant resin film also satisfies the conditions of the flammability classification described below.

[0034] Specifically, for example, the thermoplastic resin composition may contain 1 to 30 parts by mass of the flame retardant relative to 100 parts by mass of the thermoplastic resin. Alternatively, as described above, if the thermoplastic resin contained in the thermoplastic resin composition itself has suitable flame retardant properties, the composition may not contain a flame retardant.

[0035] (Other additives) The thermoplastic resin composition may contain various known additives as necessary within the scope of not impairing the effects of the present invention. For example, antioxidants, light stabilizers, weather resistance improvers, etc. may be added to improve the storage stability of the thermoplastic resin composition and to prevent discoloration or deterioration of the solidified product.

[0036] Specific examples of other additives include thermosetting elastomers, thermoplastic elastomers, silicone oils, wetting and dispersing agents, antifoaming agents, defoaming agents, natural waxes, synthetic waxes, metal salts of linear fatty acids, acid amides, esters, release agents such as paraffins, crystalline silica, fused silica, calcium silicate, alumina, calcium carbonate, talc, barium sulfate, and other powders, metal oxides, metal hydroxides, inorganic fillers such as glass fibers, carbon nanotubes, and fullerenes, organic fillers such as carbon fibers and cellulose nanofibers, colorants such as red iron oxide, silane coupling agents, conductive materials, slip agents, leveling agents, polymerization inhibitors such as hydroquinone monomethyl ether, ultraviolet absorbers, etc. These additives can be used alone or in appropriate combination of two or more.

[0037] In addition, the flame-retardant resin film made of the thermoplastic resin composition can be produced by applying any method known to those skilled in the art. The method for producing the film is not particularly limited, but examples thereof include roll coating, reverse coating, comma coating, knife coating, die coating, gravure coating, melt extrusion molding, solution casting, T-die method, and calendaring. In addition, the film can be produced by increasing the thickness or laminating resin films having different resin compositions by using a co-extrusion method or a lamination method.

[0038] The lower limit of the thickness of the flame-retardant resin film is not particularly limited, but is preferably 5 μm or more, so that the shape of the film can be easily maintained during film molding. The thickness of the flame-retardant resin film is preferably 50 μm or less, more preferably 45 μm or less, even more preferably 40 μm or less, and even more preferably 30 μm or less, 25 μm or less, or 20 μm or less. By setting the thickness of the flame-retardant resin film to 50 μm or less, the fiber-reinforced resin composite sheet in this embodiment can also be configured thin, and as a result, it can have good molding processability.

[0039] A flame-retardant resin film made of such a thermoplastic resin composition is an intermediate material for producing the fiber-reinforced resin composite sheet of this embodiment. A plurality of reinforcing fibers spread from a reinforcing fiber bundle are laminated on one or both surfaces of the flame-retardant resin film in a state of being oriented in the same direction, and the fiber-reinforced resin composite sheet of this embodiment is obtained by heating, cooling and / or pressure treatment. From the viewpoint of obtaining better flame retardant properties, it is preferable that the plurality of reinforcing fibers are laminated on both surfaces of the flame-retardant resin film.

[0040] [Reinforced fiber] The reinforcing fibers are laminated on the flame-retardant resin film made of the thermoplastic resin composition in a state where a plurality of reinforcing fibers opened from a reinforcing fiber bundle are oriented in the same direction. In this specification, the term "a state where a plurality of reinforcing fibers are oriented in the same direction" means a state where the reinforcing fibers extend in a substantially parallel direction.

[0041] By laminating a plurality of reinforcing fibers in such a state on the flame-retardant resin film (specifically on the surface of the flame-retardant resin film), the fiber-reinforced resin composite sheet in this embodiment has very excellent flame retardancy. Specifically, not only does the resin film itself have flame retardant properties, but a plurality of non-flammable reinforcing fibers (preferably carbon fibers) are laminated on the flame-retardant resin film in an exposed state without being completely impregnated, so that the spread of flames can be suppressed compared to a sheet in which the reinforcing fibers are completely impregnated in the molten resin.

[0042] The material of the reinforcing fiber is not particularly limited, but it is possible to appropriately select a fiber that is known as a reinforcing fiber constituting a fiber-reinforced resin composite sheet and that satisfies the flammability classification conditions described later when the sheet is constituted, depending on the application. Specific examples include various fibers such as carbon fiber, aramid fiber, glass fiber, boron fiber, alumina fiber, silicon nitride fiber, and basalt fiber. Among these, carbon fiber, aramid fiber, glass fiber, boron fiber, alumina fiber, and silicon nitride fiber are preferable from the viewpoint of specific strength and specific elasticity. Furthermore, carbon fiber is more preferable because it can improve the strength and corrosion resistance of a molded product using the fiber-reinforced resin composite sheet in this embodiment. As the carbon fiber, it is preferable to use PAN (polyacrylonitrile)-based carbon fiber, which has particularly high strength. When carbon fiber is used as the reinforcing fiber, it may be surface-treated with a metal. In addition, the reinforcing fibers opened from these reinforcing fiber bundles can be used in one or more appropriate combinations as long as they are oriented in the same direction.

[0043] In the fiber reinforced resin composite sheet of this embodiment, the volume fraction Vf of the reinforcing fibers in the fiber reinforced resin composite sheet is 30% or more and 65% or less. By setting the volume fraction Vf of the reinforcing fibers to 30% or more, the fiber reinforced resin composite sheet is sufficiently reinforced by the reinforcing fibers, and therefore has excellent strength, particularly tensile strength. On the other hand, by setting the volume fraction Vf of the reinforcing fibers to 65% or less, good molding processability of the fiber reinforced resin composite sheet made of thermoplastic resin can be maintained. Furthermore, by adjusting the volume fraction Vf of the reinforcing fibers within the range of 30% or more and 65% or less while taking into consideration the type of resin selected and the type and amount of the flame retardant optionally added, the fiber reinforced resin composite sheet can be made to satisfy the conditions of the flammability classification described later in detail.

[0044] The volume fraction Vf of the reinforcing fibers is preferably 35% or more, more preferably 40% or more, and even more preferably 44% or more. The volume fraction Vf of the reinforcing fibers is preferably 60% or less, more preferably 55% or less, and even more preferably 53% or less. The volume fraction Vf of the reinforcing fibers in the fiber-reinforced resin composite sheet can be adjusted within the above range by appropriately controlling not only the type and thickness of the reinforcing fibers, the fiber width in which the reinforcing fibers are oriented, and the thickness of the flame-retardant resin film, but also the temperature and pressure applied during the production of the fiber-reinforced resin composite sheet. The volume fraction Vf of the reinforcing fibers can be measured by a combustion method, a nitric acid decomposition method, a sulfuric acid decomposition method, and the like, but the volume fraction Vf of the reinforcing fibers in this specification is a value measured by the same combustion method as in the examples.

[0045] Furthermore, the thickness of the fiber reinforced resin composite sheet in this embodiment is 20 μm or more and 100 μm or less. The thickness of the fiber reinforced resin composite sheet is preferably 25 μm or more, more preferably 30 μm or more, even more preferably 35 μm or more, and even more preferably 40 μm or more. The thickness of the fiber reinforced resin composite sheet is preferably 90 μm or less, more preferably 80 μm or less, even more preferably 70 μm or less, and even more preferably 60 μm or less, 55 μm or less, or 50 μm or less.

[0046] Specifically, by making the thickness of the fiber-reinforced resin composite sheet as thin as possible within the above range, the flame-retardant resin film and the reinforcing fibers are laminated after being fused in most parts, so that the strength of the reinforcing fibers can be fully exhibited. In addition, when stress is applied, delamination of the laminate (fiber-reinforced resin composite material described later) made of the fiber-reinforced composite sheet is unlikely to occur, and the fatigue properties are also excellent. Furthermore, the molding processability when using the fiber-reinforced resin composite sheet can be made more excellent. The thickness of the fiber-reinforced resin composite sheet is also affected by the thickness of the flame-retardant resin film, but it can be kept within the above range by appropriately controlling the temperature and pressure applied during the production of the fiber-reinforced resin composite sheet.

[0047] The fiber reinforced resin composite sheet in this embodiment has a flammability classification of 5V-A or 5V-B as determined by a UL94-5V flammability test in accordance with the ASTM D5048 standard. The UL94-5V flammability test in accordance with the ASTM D5804 standard will be described in detail in the Examples below. Preferably, the flammability classification as determined by the UL94-5V flammability test in accordance with the ASTM D5048 standard is 5V-A. As described above, the flammability of the fiber reinforced resin composite sheet can be made to satisfy the conditions of the flammability classification by the type of resin selected, the type and amount of flame retardant optionally added, and the adjustment ratio within the range of 30% to 65% of the volume fraction Vf of the reinforcing fiber.

[0048] Thus, the fiber reinforced resin composite sheet in this embodiment not only has excellent flame retardancy and high heat resistance, but also has excellent reinforcing effect and fatigue resistance due to the volume fraction Vf of the reinforcing fibers, which is sufficient, and excellent moldability due to the relatively thin thickness of the fiber reinforced resin composite sheet. That is, the fiber reinforced resin composite sheet in this embodiment is suitable for use as a material for manufacturing resin molded products such as housings and parts of electrical or electronic devices such as smartphones, tablets, and laptops that may generate heat, ignite, and burn from inside the device. Furthermore, according to the fiber reinforced resin composite sheet in this embodiment, it is possible to laminate multiple fiber reinforced resin composite sheets while minimizing voids, thereby forming various shapes at high density, and therefore it is possible to manufacture fiber reinforced resin composite materials and resin molded products having excellent strength.

[0049] An example of a method for producing a fiber reinforced resin composite sheet in this embodiment will be described with reference to Fig. 1. In Fig. 1, the various symbols represent a fiber reinforced resin composite sheet production apparatus 1, a heating roller 2, a cooling roller 3, an endless belt 4, a drawing roller 5, a bobbin 6, a fiber reinforced resin composite sheet S, a flame retardant resin film R0, a reinforcing fiber bundle F0, and reinforcing fibers (reinforcing fibers opened (from the reinforcing fiber bundle)) F.

[0050] The fiber reinforced resin composite sheet S can be continuously produced, for example, by using a fiber reinforced resin composite sheet production apparatus 1 shown in Fig. 1. This fiber reinforced resin composite sheet production apparatus 1 is an apparatus that continuously produces a fiber reinforced resin composite sheet S from a reinforcing fiber bundle F0 and a flame retardant resin film R0 made of a thermoplastic resin composition.

[0051] Specifically, the fiber reinforced resin composite sheet manufacturing apparatus 1 includes multiple pairs (two pairs in FIG. 1) of heating rollers 2 arranged vertically, multiple pairs (two pairs in FIG. 1) of cooling rollers 3 arranged vertically below the heating rollers 2, a pair of endless belts 4 stretched between the heating rollers 2 and the cooling rollers 3, a pair of pull-out rollers 5 positioned below the endless belts 4, and a winding bobbin 6 arranged below the pull-out rollers 5.

[0052] Although not shown, a spreading mechanism that spreads the reinforcing fiber bundle F0 into a band shape is provided near the uppermost heating roller 2. This spreading mechanism is capable of continuously spreading the reinforcing fiber bundle F0, thereby spreading and forming a large number of continuous reinforcing fibers F so that they are oriented and extend in the same direction. The spreading mechanism may be any mechanism capable of such processing, and various mechanisms can be used, such as a mechanism that beats the reinforcing fiber bundle F0 to spread it, a mechanism that blows air on the reinforcing fiber bundle F0 to spread it, or a mechanism that applies ultrasonic waves to the reinforcing fiber bundle F0 to spread it.

[0053] In the example of Fig. 1, the spreading mechanism has a mechanism for supplying the spread reinforcing fibers F to one side of the flame-retardant resin film R0, and a mechanism for supplying the spread reinforcing fibers F to the other side of the flame-retardant resin film R0. The former mechanism is provided to introduce the reinforcing fibers F between one side of the flame-retardant resin film R0 and the heating roller 2 in contact with that side, and the latter mechanism is provided to introduce the reinforcing fibers F between the other side of the flame-retardant resin film R0 and the heating roller 2 in contact with that side. However, the spreading mechanism may be one that supplies the reinforcing fibers F only to one side of the flame-retardant resin film R0.

[0054] The heating roller 2 is a high-temperature roller heated by an electric heater or a heating medium (e.g., a heating fluid). The two pairs of heating rollers 2 heat the flame-retardant resin film R0 and the reinforcing fibers F introduced on both sides thereof while sandwiching them from both sides via the endless belt 4, thereby continuously laminating the reinforcing fibers F onto the flame-retardant resin film R0. The reinforcing fibers F are laminated onto the flame-retardant resin film R0 in a state where they are oriented in the same direction (a state where they are aligned in the vertical direction in FIG. 1).

[0055] The cooling roller 3 is a low-temperature roller cooled by a cooling medium or the like (for example, a cooling fluid). The cooling roller 3 cools the flame-retardant resin film R0 having the reinforcing fibers F laminated thereon while sandwiching the flame-retardant resin film R0 from both sides via the endless belt 4, thereby fixing the reinforcing fibers F to the flame-retardant resin film R0. This forms a fiber-reinforced resin composite sheet S in which the flame-retardant resin film R0 (resin matrix) and the reinforcing fibers F are integrated.

[0056] The pull-out roller 5 is a roller that applies tension to the molded fiber reinforced resin composite sheet S and pulls it downward.

[0057] The winding bobbin 6 is a core material for winding up the fiber reinforced resin composite sheet S. The bobbin 6 is rotationally driven by a driving source such as a motor, and sequentially winds up the fiber reinforced resin composite sheet S drawn out by the drawing roller 5, thereby forming a roll-shaped fiber reinforced resin composite sheet S.

[0058] It is also possible to produce the fiber-reinforced resin composite sheet S by a method in which the flame-retardant resin film R0 and the spread reinforcing fibers are wound up together in the same direction without using the endless belt 4 shown in FIG.

[0059] When reinforcing fibers are laminated on one side of a flame-retardant resin film R0 with the opened reinforcing fibers oriented in the same direction, the reinforcing fibers F shown in Figure 1 are fed from one side instead of both sides, thereby obtaining a fiber-reinforced resin composite sheet S in which the reinforcing fibers F are laminated on one side of the flame-retardant resin film.

[0060] <Fiber reinforced resin composite material> The fiber reinforced resin composite material in this embodiment is a fiber reinforced composite material in which a plurality of the fiber reinforced resin composite sheets in the above-described embodiment are laminated in the thickness direction.

[0061] Here, throughout this specification, the term "lamination" used in "fiber-reinforced resin composite sheets (or chopped materials thereof) are laminated" includes the meanings of "lamination with at least a portion fixed", "lamination with at least a portion bonded", "lamination with at least a portion fused", "lamination with at least a portion attached" and "lamination with at least a portion pressed" depending on the physical properties and shape of the fiber-reinforced resin composite sheets (or chopped materials thereof), the type of processing performed for lamination, and the conditions thereof. More specifically, heating, cooling and / or pressure processing may be performed as necessary during "lamination".

[0062] The fiber reinforced resin composite sheets to be laminated may be cut into pieces or the like as necessary to match the shape of the desired fiber reinforced resin composite material, and then laminated. The number of laminated fiber reinforced resin composite sheets is not particularly limited, and may be appropriately set according to the size of the desired fiber reinforced resin composite material. The fiber reinforced resin composite sheets may be laminated in any state with respect to the fiber direction of the reinforcing fibers, but are preferably laminated in a state in which the fiber directions of the reinforcing fibers of the multiple fiber reinforced resin composite sheets have an angle difference in a two-dimensional direction.

[0063] For example, a fiber-reinforced composite material can be mentioned in which two or more fiber-reinforced resin composite sheets are laminated in the thickness direction, preferably 4×n sheets (n is an integer of 1 or more), so that the fiber directions of the reinforcing fibers have an angular difference of about 45° in two-dimensional directions, in other words, four axial directions of 0°, 45°, -45°, and 90° in a two-dimensional plane (hereinafter also referred to as "four axial directions with an angular difference of 45°"). By stacking the fiber-reinforced resin composite sheets in this way, the tensile strength and bending strength along each fiber direction can be improved, and therefore the overall strength of the fiber-reinforced resin composite material can be effectively improved.

[0064] Alternatively, another fiber reinforced resin composite material in this embodiment may be obtained by stacking the fiber reinforced resin composite sheet in the above-described embodiment in the thickness direction in the form of a plurality of chopped pieces.

[0065] A plurality of chopped materials can be produced by, for example, cutting the fiber reinforced resin composite sheet S shown in FIG. 1 in the above-described embodiment into thin strips in the longitudinal and transverse directions.

[0066] As a specific example, chopped material can be produced by the following procedure. The procedure will be described with reference to FIG. 2. In FIG. 2, the respective symbols represent a fiber reinforced resin composite sheet S, a cut X, a cut Y, a section I, a section II, and chopped material C. First, as shown in FIG. 2, cuts X extending in the longitudinal direction are formed. That is, while the fiber reinforced resin composite sheet S is fed in the longitudinal direction, a large number of continuous cuts X in the longitudinal direction are formed in section I along the feed path. The cuts X can be formed, for example, by using a shredding device including a large number of blades arranged at equal intervals in the width direction of the fiber reinforced resin composite sheet S.

[0067] Next, in the following section II, continuous incisions Y are formed from one end to the other end in the width direction of the fiber reinforced resin composite sheet S. The incisions Y can be formed, for example, by using a rotary cutter or the like. The incisions Y are formed each time the fiber reinforced resin composite sheet S is fed a fixed distance in the longitudinal direction. As a result, a large number of rectangular chopped materials C having short sides with a length corresponding to the pitch of the incisions X and long sides with a length corresponding to the pitch of the incisions Y are cut out.

[0068] As described above, the fiber reinforced resin composite sheet S is a sheet in which a large number of reinforcing fibers F are laminated in a state in which they are oriented in the same direction in the longitudinal direction. Therefore, each chopped material C cut out from the fiber reinforced resin composite sheet S is also laminated in a state in which a large number of reinforcing fibers F are oriented in the same direction in the longitudinal direction (direction of the long side). In other words, the chopped material C includes a flame retardant resin film R0 and a large number of reinforcing fibers F laminated on the flame retardant resin film R0 in a state in which they are oriented in the same direction.

[0069] The larger the size of the chopped material C, the stronger the fiber reinforced resin composite material or resin molded product can be produced, but the formability will be lower. On the other hand, the smaller the size of the chopped material C, the better the formability and the more flexible the shape of the fiber reinforced resin composite material or resin molded product can be produced, but the strength of the product will be lower. By taking into consideration the balance between formability and mechanical properties depending on the size of the chopped material C, adjusting the size of the chopped material C and appropriately controlling the balance, it is possible to impart properties suitable for the application of the molded product.

[0070] The length of the short side of the chopped material C is preferably 2 mm or more, more preferably 3 mm or more, even more preferably 4 mm or more, still more preferably 4.5 mm or more, and is preferably 50 mm or less, more preferably 40 mm or less, even more preferably 30 mm or less, or even more preferably 20 mm or less, 15 mm or less, or 10 mm or less. The length of the long side of the chopped material C is preferably 2 mm or more, more preferably 4 mm or more, even more preferably 6 mm or more, or even more preferably 8 mm or more or 10 mm or more, and is preferably 80 mm or less, more preferably 70 mm or less, even more preferably 60 mm or less, or even more preferably 50 mm or less, or 45 mm or less.

[0071] The thickness of the chopped material C is the same as that of the fiber reinforced resin composite sheet in the above embodiment, and is 20 μm or more and 100 μm or less. The preferred thickness is also the same as that of the fiber reinforced resin composite sheet in the above embodiment. That is, like the fiber reinforced resin composite sheet in the above embodiment, it is possible to laminate multiple sheets with a small size as the chopped material C while minimizing voids due to its thinness. Therefore, it is possible to manufacture a fiber reinforced resin composite material having a higher density, significantly excellent strength and low water absorption, and a resin molded product using the same. Furthermore, by forming the chopped material C into a shape, the formability is improved, and a resin molded product having a complex shape can also be manufactured.

[0072] In the fiber-reinforced composite material of this embodiment, such multiple chopped materials C may be stacked in any state in which the fiber direction of the reinforcing fibers is inclined, but it is preferable that the multiple chopped materials C are stacked in a state in which the fiber direction of the reinforcing fibers is two-dimensionally random (quasi-isotropic).

[0073] An example of a method for manufacturing such a fiber-reinforced composite material will be described with reference to FIG. 3. In FIG. 3, the respective symbols represent a belt conveyor 7, a release film 8, a heating roller 9, a bobbin 10 for laminated chopped sheets, chopped material C, a section XI, a section XII, a section XIII, and a laminated chopped sheet CS. First, as shown in FIG. 3, a belt conveyor 7 is rotated, which is arranged substantially horizontally, and a large number of chopped materials C are distributed and arranged on its upper surface. For example, a drop device that vibrates and drops the chopped materials C from above the belt conveyor 7 can be used to distribute and arrange the chopped materials C. Then, by repeating the dropping operation of the chopped materials C using such a drop device, the density of the chopped materials C on the upper surface of the belt conveyor 7 and the number of layers are increased. That is, by repeatedly dropping the chopped material C using a dropping device in multiple sections XI, XII, XIII, etc. in the rotation direction of the belt conveyor 7, a large number of chopped materials C are stacked on the belt conveyor 7 so that the fiber direction of the reinforcing fibers F contained in each chopped material C (in other words, the longitudinal direction of the chopped material C) varies in various directions on the horizontal plane and multiple chopped materials C are piled up in the thickness direction.

[0074] Then, from the end side where a large number of chopped materials C are stacked, the chopped materials C stacked on the upper surface of the belt conveyor 7 are pressurized and heated using a heating roller 9 or a heat-resistant endless belt via a release film 8, and a large number of chopped materials C are integrated. That is, the stacked chopped materials C are bonded to each other by the pressurization and heat treatment using the heating roller 9. In this way, the dispersion and stacking of a large number of chopped materials C on the upper surface of the belt conveyor 7 and the pressurization and heat treatment using the heating roller 9 are continuously performed. After that, a laminated chopped sheet CS in which a plurality of chopped materials C are stacked and integrated with each other is continuously formed in a scroll shape using a laminated chopped sheet bobbin 10 or the like. A partial cross section of the continuously formed scroll-shaped laminated chopped sheet CS is shown in FIG. 4. In FIG. 4, each symbol represents the chopped material C, the laminated chopped sheet (fiber reinforced composite material) CS, and the thickness t of the laminated chopped sheet CS. The thickness t of this laminated chopped sheet CS, that is, the total thickness of the chopped materials C stacked on top of a plurality of sheets, can be set appropriately.

[0075] Alternatively, as another example of a method for producing a fiber-reinforced composite material, when producing a laminated chopped sheet, a large number of chopped materials C may be laminated on a carrier sheet made of a thermoplastic resin composition.

[0076] In detail, a large number of chopped materials C are distributed on the upper surface of the carrier sheet while the carrier sheet is sent out in the longitudinal direction like the belt conveyor 7 shown in FIG. 3. For distributing the chopped materials C, for example, a drop device similar to that described above can be used from above the carrier sheet. The dropping operation of the chopped materials C using such a drop device may be repeated at multiple locations in the feed direction of the carrier sheet as described above to increase the density and number of stacked chopped materials C on the carrier sheet. That is, a large number of chopped materials C may be stacked on the carrier sheet so that the fiber direction of the reinforcing fibers F contained in each chopped material C varies in various directions on the horizontal plane and multiple chopped materials C are stacked in the thickness direction.

[0077] Thereafter, the carrier sheet and the chopped material C thereon are pressurized and heated using a heating roller to integrate the carrier sheet and the chopped material C. That is, the pressurization and heat treatment using the heating roller causes the carrier sheet to support the chopped material C in a stacked state, and the stacked chopped materials C are bonded to each other. By this method, a stacked chopped sheet CS in which multiple chopped materials C are stacked on the upper surface of the carrier sheet can be formed.

[0078] The material of the carrier sheet can be basically the same thermoplastic resin composition as the thermoplastic resin composition of the chopped material C, a resin composition containing other thermoplastic resins having flame retardant properties, or a thermoplastic resin composition that does not have flame retardant properties. These thermoplastic resin compositions may be composed of a thermoplastic resin alone without additives.

[0079] Although the case where the chopped material C is laminated only on the upper surface of the carrier sheet to produce the laminated chopped sheet CS has been described, it is of course possible to laminate the chopped material C on both sides of the carrier sheet. In this case, the operation of laminating the chopped material C on the carrier sheet (i.e., the operation of randomly arranging the chopped material C in multiple layers and applying heat and pressure) may be performed on the upper and lower surfaces of the carrier sheet in order. That is, after laminating the chopped material C on the upper surface of the carrier sheet, the carrier sheet is turned over so that the lower surface of the carrier sheet is facing up, and the operation of laminating the chopped material C in that state is repeated in the same manner. As a result, a laminated chopped sheet in which the chopped material C is laminated on both sides of the carrier sheet can be produced.

[0080] <Resin molded products> The resin molded product in this embodiment includes the fiber reinforced resin composite material in the above-described embodiment.

[0081] The resin molded product may be any molded product of any shape that can be produced using the fiber-reinforced resin composite material in the above-mentioned embodiment by any molding method known to those skilled in the art. For example, molded products such as housings and parts used in electrical or electronic devices such as smartphones, tablets, laptops, video cameras, mobile devices, and other household electrical appliances can be mentioned.

[0082] The manufacturing method of the resin molded product in this embodiment is not particularly limited. For example, first, a plurality of laminated chopped sheets CS described in the above embodiment cut into a predetermined size are prepared, and the laminated chopped sheets CS are stacked in the thickness direction and placed in a mold such as a heat press. After that, the stacked laminated chopped sheets CS are heated and / or pressed, and cooled as necessary, to manufacture a resin molded product.

[0083] According to the above-mentioned manufacturing method, since the flame-retardant resin film R0 made of a highly heat-resistant thermoplastic resin composition is used, it is possible to obtain a resin molded product in which the physical properties of the tensile strength and bending strength of the resin molded product are unlikely to decrease even under high temperature conditions. Furthermore, since the resin molded product is molded using the laminated chopped sheet CS containing a sufficient amount of reinforcing fibers F such that the volume fraction Vf of the reinforcing fibers is 30% or more and 65% or less, an excellent reinforcing effect due to the reinforcing fibers F can be obtained, and the strength of the resin molded product can be increased. Furthermore, the laminated chopped sheet CS in which the fiber directions of the reinforcing fibers F of the multiple chopped materials C are laminated in a state where they are two-dimensionally random (quasi-isotropic), can reduce the possibility that the reinforcing fibers F will be chopped when the laminated chopped sheet CS is pressed, and can promote the flow of the resin during press processing to increase the degree of freedom in the shape of the resin molded product. As a result, it is possible to mold various shapes of resin molded products without any problems while isotropically exerting the reinforcing effect due to the reinforcing fibers F.

[0084] The outline of the present invention has been described above. The fiber reinforced resin composite sheet, the fiber reinforced resin composite material, and the resin molded product including the same in this embodiment can be summarized as follows.

[0085] A fiber-reinforced resin composite sheet according to a first aspect of the present invention is a fiber-reinforced resin composite sheet including: a flame-retardant resin film made of a thermoplastic resin composition having a glass transition temperature Tg of 90° C. or higher; and a plurality of reinforcing fibers laminated on the flame-retardant resin film in a state in which the plurality of reinforcing fibers are spread from a reinforcing fiber bundle and oriented in the same direction; The flammability classification of the flame-retardant resin film is VTM-0 as determined in a UL94 VTM flammability test in accordance with the ASTM D4804 standard; The volume fraction Vf of the reinforcing fibers is 30% or more and 65% or less, The thickness of the fiber reinforced resin composite sheet is 20 μm or more and 100 μm or less, The fiber reinforced resin composite sheet has a flammability classification of 5V-A or 5V-B as determined in a UL94-5V flammability test in accordance with ASTM D5048 standard.

[0086] A fiber-reinforced resin composite sheet having such a configuration has excellent flame retardancy, good moldability, and sufficient tensile strength under high temperature conditions.

[0087] The plurality of reinforcing fibers are preferably laminated on one or both surfaces of the flame-retardant resin film.

[0088] A fiber-reinforced resin composite sheet having such a configuration has multiple reinforcing fibers laminated on one or both surfaces of a flame-retardant resin film, and therefore has extremely superior flame retardancy compared to a prepreg in which the reinforcing fibers are completely impregnated with the molten resin.

[0089] It is more preferable that the plurality of reinforcing fibers are laminated on both surfaces of the flame-retardant resin film.

[0090] A fiber-reinforced resin composite sheet having such a structure certainly has extremely excellent flame retardancy as compared with a prepreg in which the reinforcing fibers are completely impregnated with the molten resin.

[0091] It is more preferable that the thermoplastic resin composition contains a polycarbonate resin and one or more flame retardants selected from a halogen-based flame retardant, a phosphorus-based flame retardant, a silicone-based flame retardant, and an inorganic flame retardant.

[0092] A fiber-reinforced resin composite sheet having such a configuration reliably has excellent flame retardancy.

[0093] It is particularly preferable that the thermoplastic resin composition contains one or more selected from polyphenylene sulfide resin, polyether ether ketone resin, polyether ketone ketone resin, polyether imide resin, polyether sulfone resin and liquid crystal polymer resin.

[0094] A fiber-reinforced resin composite sheet having such a configuration reliably has excellent flame retardancy.

[0095] More preferably, the reinforcing fibers are carbon fibers.

[0096] A fiber-reinforced resin composite sheet having such a configuration can improve the strength, corrosion resistance, etc. of a molded article using the same, and also ensures extremely excellent flame retardancy due to the non-flammable carbon fiber.

[0097] It is even more preferable that the thickness of the flame-retardant resin film is 5 μm or more and 50 μm or less.

[0098] The fiber-reinforced resin composite sheet having such a structure can be constructed so that the sheet itself is thin, and as a result, the sheet has good moldability.

[0099] A fiber reinforced resin composite material according to a second aspect of the present invention is a fiber reinforced composite material in which a plurality of fiber reinforced resin composite sheets according to the first aspect are laminated in a thickness direction, The fiber reinforced composite material is laminated in a state where the fiber directions of the reinforcing fibers of the plurality of fiber reinforced resin composite sheets have an angular difference in a two-dimensional direction.

[0100] A fiber reinforced resin composite material having such a configuration can effectively improve the overall strength of the fiber reinforced resin composite material.

[0101] Alternatively, a fiber reinforced resin composite material according to a second aspect of the present invention is a fiber reinforced composite material in which the fiber reinforced resin composite sheet according to the first aspect is laminated in a thickness direction in the form of a plurality of chopped materials, The chopped material is formed so that the fiber reinforced resin composite sheet has a rectangular shape with a short side length of 2 mm or more and 50 mm or less and a long side length of 2 mm or more and 80 mm or less, The fiber reinforced composite material is laminated in a state in which the fiber directions of the reinforcing fibers of the plurality of chopped materials are two-dimensionally random.

[0102] A fiber-reinforced resin composite material having such a structure can be molded into resin molded products of various shapes without any problems while isotropically exerting the reinforcing effect of the reinforcing fibers.

[0103] A resin molded article according to a third aspect of the present invention includes the fiber reinforced resin composite material according to the second aspect.

[0104] A resin molded article having such a structure has excellent flame retardancy and sufficient tensile strength under high temperature conditions. EXAMPLES

[0105] The present invention will be described in more detail below with reference to examples, but the present invention is not limited to these examples in any way.

[0106] Test pieces of the fiber reinforced resin composite sheets and fiber reinforced resin composite materials of Examples 1-1 to 1-4 and Comparative Examples 1-1 to 1-5 were prepared as follows.

[0107] (Example 1-1) In order to produce a fiber-reinforced resin composite sheet, a flame-retardant resin film made of a thermoplastic resin composition was prepared. In Example 1-1, a flame-retardant resin film made of a thermoplastic resin composition containing a polycarbonate resin and containing a non-bromine-based and non-phosphorus-based flame retardant was used. The glass transition temperature Tg of this thermoplastic resin composition is 148°C to 150°C. The thickness of the flame-retardant resin film is 20 μm.

[0108] Using this flame-retardant resin film and carbon fiber (manufactured by Toray Industries, Inc., "TORAYCA", grade: T-700 (PAN-based carbon fiber), fiber diameter: 7 μm, number of filaments: 12K, fineness: 800 tex) as reinforcing fiber, the fiber-reinforced resin composite sheet of the present embodiment described above was obtained while spreading the carbon fiber bundles by the manufacturing device shown in FIG. 1. At this time, the pressure was 0.5 MPa, the roll temperature (the temperature of the heating roller 2 shown in FIG. 1) was 270° C., and the feed speed was 10 m / min. The obtained fiber-reinforced resin composite sheet has the spread carbon fiber bundles laminated on both sides of the flame-retardant resin film. The volume content Vf of the carbon fiber in the fiber-reinforced resin composite sheet was 53%, and the thickness of the fiber-reinforced resin composite sheet was 40 μm to 50 μm.

[0109] The obtained fiber reinforced resin composite sheets were stacked 40 sheets so that the opened carbon fibers were in the direction of 0° angle difference. The stacked fiber reinforced resin composite sheets were placed in a mold and pressed while heating for 15 minutes under conditions of 300°C and 2 MPa, and then pressed while cooling for 10 minutes under conditions of room temperature and 3 MPa. A fiber reinforced resin composite material of 300 mm x 300 mm x 2 mm (thickness) was taken out from the mold and cut out from the fiber reinforced resin composite material to obtain a fiber reinforced resin composite test piece of 150 mm x 150 mm x 2 mm (thickness). The volume fraction Vf of the carbon fibers of the test piece was also 53%.

[0110] (Example 1-2) In Example 1-2, instead of the thermoplastic resin composition containing the polycarbonate resin to which the flame retardant of Example 1-1 was added, a thermoplastic resin composition consisting of only polyphenylene sulfide (PPS) resin having flame retardant properties (manufactured by Solvay, "Ryton (registered trademark) QC200N") was used. The glass transition temperature Tg of the thermoplastic resin composition consisting of polyphenylene sulfide (PPS) resin is 90°C. Pellets of polyphenylene sulfide (PPS) resin were extruded using an extruder equipped with a T-die at a molding temperature of 280°C to produce a flame-retardant resin film consisting of polyphenylene sulfide (PPS) resin having a thickness of 25 μm.

[0111] Using this flame-retardant resin film and the carbon fiber described in Example 1-1, a fiber-reinforced resin composite sheet was obtained by opening the carbon fiber bundles using the manufacturing device shown in Fig. 1. At this time, the pressure was 0.5 MPa, the roll temperature (the temperature of the heating roller 2 shown in Fig. 1) was 280°C, and the feed speed was 20 m / min, and a fiber-reinforced resin composite sheet having the same shape as in Example 1-1 was obtained. The volume fraction Vf of the carbon fiber in the fiber-reinforced resin composite sheet was 44.7%, and the thickness of the fiber-reinforced resin composite sheet was 50 µm.

[0112] Using the obtained fiber-reinforced resin composite sheet, a test piece of a fiber-reinforced resin composite material having a size of 150 mm x 150 mm x 2 mm (thickness) was obtained by the same method as in Example 1-1 described above. The volume fraction Vf of the carbon fiber of the test piece was also 44.7%.

[0113] (Examples 1-3) A 50 μm-thick fiber-reinforced resin composite sheet and a 150 mm × 150 mm × 2 mm (thickness) fiber-reinforced resin composite test piece were obtained in the same manner as in Example 1-2, except that a 25 μm-thick film made of polyphenylene sulfide (PPS) resin was further added when laminating the carbon fiber fiber-reinforced resin composite sheets so that the volume fraction Vf of the carbon fiber in the fiber-reinforced resin composite sheet was 35%.

[0114] (Examples 1 to 4) Instead of the flame-retardant resin film made of polyphenylene sulfide (PPS) resin with a thickness of 25 μm produced in Example 1-2, a polyether ether ketone (PEEK) resin film (manufactured by Mitsubishi Chemical, "Superio UT (registered trademark) αKN-type") having flame-retardant properties and a thickness of 20 μm was used. The glass transition temperature Tg of the thermoplastic resin composition made of polyether ether ketone (PEEK) resin is 143°C to 147°C.

[0115] Using this flame-retardant resin film and the carbon fiber described in Example 1-1, a fiber-reinforced resin composite sheet was obtained by opening the carbon fiber bundles using the manufacturing device shown in Fig. 1. At this time, the pressure was 0.5 MPa, the roll temperature (the temperature of the heating roller 2 shown in Fig. 1) was 360°C, and the feed speed was 10 m / min, and a fiber-reinforced resin composite sheet having the same shape as in Example 1-1 was obtained. The volume fraction Vf of the carbon fiber in the fiber-reinforced resin composite sheet was 53%, and the thickness of the fiber-reinforced resin composite sheet was 40 µm.

[0116] Using the obtained fiber-reinforced resin composite sheet, a test piece of a fiber-reinforced resin composite material having a size of 150 mm x 150 mm x 2 mm (thickness) was obtained by the same method as in Example 1-1 described above. The volume fraction Vf of the carbon fiber of the test piece was also 53%.

[0117] (Comparative Example 1-1) As Comparative Example 1-1, a commercially available polyamide 6 resin matrix fiber reinforced resin composite sheet (manufactured by TCAC, "TC910") was used, which is manufactured by impregnating carbon fiber bundles in molten resin without spreading them. The glass transition temperature Tg of the polyamide 6 resin matrix is ​​about 50°C (reference value). The volume fraction Vf of the carbon fiber in the fiber reinforced resin composite sheet was 48%, and the thickness of the fiber reinforced resin composite sheet was 180 μm.

[0118] Fourteen fiber-reinforced resin composite sheets were laminated so that the carbon fiber bundles were oriented at an angle of approximately 0°. Then, a test piece of a fiber-reinforced resin composite material measuring 150 mm x 150 mm x 2 mm (thickness) was obtained by the same method as in Example 1-1 described above. The volume fraction Vf of the carbon fiber in the test piece was also 48%.

[0119] (Comparative Example 1-2) In Comparative Example 1-2, a fiber-reinforced resin composite sheet having a thickness of 30 μm was obtained in the same manner as in Example 1-1 described above, except that the amount of carbon fiber laminated on both sides of the flame-retardant resin film containing polycarbonate resin to which a flame retardant had been added was reduced so that the volume fraction Vf of the carbon fiber in the fiber-reinforced resin composite sheet was 25%.

[0120] The obtained fiber reinforced resin composite sheets were stacked 74 sheets so that the opened carbon fibers were in the direction of 0° angle difference. Then, by the same method as in Example 1-1 described above, a test piece of fiber reinforced resin composite material of 150 mm × 150 mm × 2 mm (thickness) was obtained. The volume fraction Vf of the carbon fiber of the test piece was also 25%.

[0121] (Comparative Example 1-3) In Comparative Example 1-3, a fiber-reinforced resin composite sheet having a thickness of 70 μm was obtained by the same method as in Example 1-1 described above, except that the amount of carbon fiber laminated on both sides of the flame-retardant resin film containing polycarbonate resin to which a flame retardant had been added was increased so that the volume fraction Vf of the carbon fiber in the fiber-reinforced resin composite sheet was 70%.

[0122] Using the obtained fiber-reinforced resin composite sheet, an attempt was made to prepare a fiber-reinforced resin composite test piece of 150 mm × 150 mm × 2 mm (thickness) by the same method as in Example 1-1 described above, but the impregnation between the fibers and the resin was poor, and the test piece could not be molded.

[0123] (Comparative Examples 1-4) In Comparative Example 1-4, a fiber-reinforced resin composite sheet having a thickness of 35 μm was obtained in the same manner as in Example 1-2 described above, except that the amount of carbon fiber laminated on both sides of a flame-retardant resin film made of polyphenylene sulfide (PPS) resin was reduced so that the volume fraction Vf of the carbon fiber in the fiber-reinforced resin composite sheet was 25%.

[0124] The obtained fiber reinforced resin composite sheets were stacked 64 sheets so that the opened carbon fibers were in the direction of 0° angle difference. Then, by the same method as in Example 1-2 described above, a test piece of fiber reinforced resin composite material of 150 mm × 150 mm × 2 mm (thickness) was obtained. The volume fraction Vf of the carbon fiber of the test piece was also 25%.

[0125] (Comparative Examples 1-5) In Comparative Example 1-5, a fiber-reinforced resin composite sheet having a thickness of 85 μm was obtained by the same method as in Example 1-2 described above, except that the amount of carbon fiber laminated on both sides of a flame-retardant resin film made of polyphenylene sulfide (PPS) resin was increased so that the volume fraction Vf of the carbon fiber in the fiber-reinforced resin composite sheet was 70%.

[0126] Using the obtained fiber-reinforced resin composite sheet, an attempt was made to prepare a fiber-reinforced resin composite test piece of 150 mm × 150 mm × 2 mm (thickness) by the same method as in Example 1-2 described above, but the impregnation between the fibers and the resin was poor, and the test piece could not be molded.

[0127] The volume fraction Vf of the reinforcing fibers in the fiber-reinforced resin composite sheet and the fiber-reinforced resin composite material was measured by a combustion method. The glass transition temperature Tg of each thermoplastic resin composition or the thermoplastic resin itself is a temperature measured by a differential scanning calorimeter (DSC).

[0128] <Flame retardancy evaluation of thermoplastic resin film or resin matrix> The resin films produced in Examples 1-1 to 1-4 and Comparative Examples 1-2 to 1-5, and the polyamide 6 resin matrix used in Comparative Example 1-1 were evaluated for their flammability by a UL94VTM flammability test in accordance with the ASTM D4804 standard. Specifically, a test piece (dimensions: 200±5mm×50±1mm×tmm) was rolled into a cylindrical shape, attached vertically to a clamp, and exposed to a 20mm flame for 3 seconds twice, and the test piece was evaluated as "VTM-0", "VTM-1", "VTM-2" or "Not" based on the flammability behavior. t was set to 20 to 25 μm. Specific evaluation criteria are shown in Table 1 below.

[0129] [Table 1]

[0130] <Flame retardancy evaluation of fiber-reinforced resin composite sheets> The flammability of the fiber-reinforced resin composite sheet test pieces prepared in Examples 1-1 to 1-4 and Comparative Examples 1-1, 1-2, and 1-4 was evaluated by the UL94-5V flammability test in accordance with the ASTM D5048 standard. Specifically, a rectangular test piece (dimensions: 125±5mm×13±0.5×tmm) was attached vertically to a clamp, and 5 seconds of indirect flame exposure with a 125mm flame was performed five times. Furthermore, a flat test piece (dimensions: 150±5mm×150±5×tmm) was held horizontally, and 5 seconds of indirect flame exposure with a 125mm flame was performed five times from below. Based on these flammability behaviors, a judgment was made as "5V-B", "5V-A", or "Not". Note that t=2mm was set. Specific judgment criteria are shown in Table 2 below. Note that in Comparative Examples 1-3 and 1-5, the fiber-reinforced resin composite sheet test pieces were not able to be tested because the impregnation between the fiber and the resin was poor.

[0131] [Table 2]

[0132] <Evaluation of tensile strength (MPa) of test pieces of fiber-reinforced resin composite material> The tensile strength of the test pieces of the fiber reinforced resin composite materials of Examples 1-1 to 1-4 and Comparative Examples 1-1, 1-2, and 1-4 was measured in accordance with JIS K 7165: 2008. As described above, in Comparative Examples 1-3 and 1-5, the test pieces of the fiber reinforced resin composite materials could not be molded, and therefore the test could not be performed.

[0133] The properties and evaluation results of the thermoplastic resin films or resin matrices and fiber reinforced resin composite sheets in Examples 1-1 to 1-4 and Comparative Examples 1-1 to 1-5 are summarized in Tables 3 and 4 below.

[0134] [Table 3]

[0135] [Table 4]

[0136] As is clear from the results in Table 3 above, the resin films and fiber-reinforced resin composite sheets of Examples 1-1 to 1-4 had excellent flame retardancy compared to the polyamide 6 resin matrix and fiber-reinforced resin composite sheet of Comparative Example 1-1.

[0137] Furthermore, the fiber reinforced resin composite sheets of Examples 1-1 to 1-4 could be formed with a significantly thinner thickness than the fiber reinforced resin composite sheet of Comparative Example 1-1, which was produced by impregnating the carbon fiber bundles into a resin matrix without opening them. In addition, the test pieces of the fiber reinforced resin composite materials of Examples 1-2 and 1-3 had a high tensile strength, contrary to the results usually expected, despite the fact that the volume fraction Vf of the reinforcing fibers was smaller than that of the test piece of the fiber reinforced resin composite material of Comparative Example 1-1. This is because the fiber reinforced resin composite sheets of Examples 1-1 to 1-4 are composed of thin fiber reinforced resin composite sheets stacked on top of each other, so the dispersion of the reinforcing fibers and the resin is good, and it is assumed that interlayer peeling is less likely to occur and the original strength of the fibers is expressed compared to the laminate in Comparative Example 1-1 composed of thick layers. In this way, the fiber reinforced resin composite sheets of Examples 1-1 to 1-4 have excellent moldability as intermediate materials, and the tensile strength of the fiber reinforced resin composite materials produced from the sheets was also excellent.

[0138] Furthermore, as can be seen from the results of Comparative Examples 1-2 and 1-4 in Table 4 above, when the volume fraction Vf of the reinforcing fibers was reduced to 25%, the tensile strength of the fiber-reinforced resin composite material was significantly reduced. Also, as can be seen from the results of Comparative Examples 1-3 and 1-5 in Table 4 above, when the volume fraction Vf of the reinforcing fibers was increased to 70%, the impregnation of the fibers and the resin in the obtained fiber-reinforced resin composite sheet was deteriorated, and as a result, the moldability was deteriorated, so that the fiber-reinforced resin composite material could not be molded. From these results, it can be seen that unless the volume fraction Vf of the reinforcing fibers is adjusted to a value within a specific range specified for the fiber-reinforced resin composite sheet of this embodiment, a fiber-reinforced resin composite sheet that has both good moldability and sufficient tensile strength under high temperature conditions cannot be obtained.

[0139] The glass transition temperature Tg of the resin film (thermoplastic resin composition or thermoplastic resin) used in Examples 1-1 to 1-4 is significantly higher than the glass transition temperature Tg of the polyamide 6 resin matrix used in Comparative Example 1-1. Therefore, it is expected that the fiber reinforced resin composite sheets of Examples 1-1 to 1-4 and the fiber reinforced resin composite materials produced therefrom have heat resistance and good strength, such as tensile strength (or bending strength), even under high temperature conditions. Furthermore, it is expected that the thermoplastic resins of Reference Examples 1 to 4 (polyetherketoneketone (PEKK) resin, polyetherimide (PEI) resin, polyethersulfone (PES) resin, and liquid crystal polymer (LCP) resin) shown in Table 5 below, which have high glass transition temperatures Tg and high flammability, will also exhibit the same effects as the present invention.

[0140] [Table 5]

[0141] Further, additional experiments were conducted to evaluate the flame retardancy of the fiber reinforced resin composite sheets. Specifically, additional experiments were conducted to investigate the relationship between the structure of the fiber reinforced resin composite sheet and the flame retardancy of the sheet. First, test pieces of the fiber reinforced resin composite sheets in Examples 2-1 and 2-2 and Comparative Examples 2-1 and 2-2 were prepared by the following method.

[0142] (Example 2-1) In Example 2-1, a fiber reinforced resin composite sheet containing a polycarbonate resin to which a flame retardant was added was obtained by the same method as in Example 1-1 described above. The volume fraction Vf of the carbon fiber in the fiber reinforced resin composite sheet was 53%, and the thickness of the fiber reinforced resin composite sheet was 40 to 50 μm. Next, a test piece of the fiber reinforced resin composite sheet having a size of 13 mm × 125 mm × 40 to 50 μm (thickness) was cut out from the obtained fiber reinforced resin composite sheet.

[0143] The cross section of the test piece of the fiber reinforced resin composite sheet prepared was observed using a laser microscope ("VK-X160", manufactured by Keyence Corporation). As shown in Fig. 5, the cross section of the test piece of the fiber reinforced resin composite sheet in Example 2-1 shows a state in which a plurality of carbon fibers are laminated on both sides of a flame retardant resin film containing a polycarbonate resin to which a flame retardant has been added, specifically, a state in which a plurality of carbon fibers are impregnated from the surface of the film to the inside in approximately half of each carbon fiber.

[0144] (Example 2-2) In Example 2-2, a fiber-reinforced resin composite sheet containing polyphenylene sulfide (PPS) resin was obtained by the same method as in Example 1-2 described above. The volume fraction Vf of carbon fiber relative to the fiber-reinforced resin composite sheet was 44.7%, and the thickness of the fiber-reinforced resin composite sheet was 50 μm. Next, a test piece of the fiber-reinforced resin composite sheet measuring 13 mm × 125 mm × 50 μm (thickness) was cut out from the obtained fiber-reinforced resin composite sheet.

[0145] The cross section of the test piece of the fiber reinforced resin composite sheet prepared was observed in the same manner as in Example 2-1. As shown in Fig. 5, the cross section of the test piece of the fiber reinforced resin composite sheet in Example 2-2 showed a state in which a plurality of carbon fibers were laminated on both sides of a flame retardant resin film made of polyphenylene sulfide (PPS) resin, specifically, a plurality of carbon fibers were impregnated from the surface of the film to the inside in approximately half of each carbon fiber.

[0146] (Comparative Example 2-1) In Comparative Example 2-1, first, a fiber-reinforced resin composite sheet containing a polycarbonate resin to which a flame retardant was added was obtained by the same method as in Example 1-1 described above. Furthermore, the sheet was sandwiched between iron plates heated to 300°C and pressed at 5 kgf x 60 seconds using a press machine to obtain a fiber-reinforced resin composite sheet containing a polycarbonate resin to which a flame retardant was added in Comparative Example 2-1. The volume fraction Vf of the carbon fiber relative to the fiber-reinforced resin composite sheet was 53%, and the thickness of the fiber-reinforced resin composite sheet was 38 μm. Next, a test piece of a fiber-reinforced resin composite sheet having a size of 13 mm x 125 mm x 38 μm (thickness) was cut out from the obtained fiber-reinforced resin composite sheet.

[0147] The cross section of the test piece of the fiber reinforced resin composite sheet prepared was observed in the same manner as in Example 2-1. As shown in Fig. 5, the cross section of the test piece of the fiber reinforced resin composite sheet in Comparative Example 2-1 showed that a plurality of carbon fibers were completely impregnated in the flame retardant resin film containing the polycarbonate resin to which the flame retardant was added.

[0148] (Comparative Example 2-2) In Comparative Example 2-2, first, a fiber-reinforced resin composite sheet containing polyphenylene sulfide (PPS) resin was obtained by the same method as in Example 1-2 described above. Furthermore, the sheet was sandwiched between iron plates heated to 330°C and pressed with a press at 5 kgf x 60 seconds to obtain a fiber-reinforced resin composite sheet containing polyphenylene sulfide (PPS) resin in Comparative Example 2-2. The volume fraction Vf of carbon fiber in the fiber-reinforced resin composite sheet was 44.7%, and the thickness of the fiber-reinforced resin composite sheet was 42 μm. Next, a test piece of a fiber-reinforced resin composite sheet measuring 13 mm x 125 mm x 42 μm (thickness) was cut out from the obtained fiber-reinforced resin composite sheet.

[0149] The cross section of the test piece of the fiber reinforced resin composite sheet prepared was observed in the same manner as in Example 2-1. As shown in Fig. 5, the cross section of the test piece of the fiber reinforced resin composite sheet in Comparative Example 2-2 showed that a plurality of carbon fibers were completely impregnated inside the flame retardant resin film made of polyphenylene sulfide (PPS) resin.

[0150] <Additional flame retardancy test for fiber-reinforced resin composite sheets> The flame retardancy of the fiber-reinforced resin composite sheet test pieces prepared in Examples 2-1 and 2-2 and Comparative Examples 2-1 and 2-2 was evaluated by a method different from the above-mentioned method. As a test method, first, the fiber-reinforced resin composite sheet test piece prepared was hung by a clamp. Next, the flame of the prepared gas burner was adjusted so that it was blue. After that, the gas burner was moved so that the fiber-reinforced resin composite sheet test piece hung by the clamp was located about 1 cm away from the tip of the gas burner flame. In this way, the flame was applied from the bottom of the fiber-reinforced resin composite sheet test piece hung by the clamp, and the initial ignition state, specifically, the state 1 second after ignition was observed.

[0151] FIG. 6 is an image showing the results of the additional flame retardancy test of the test pieces of each fiber reinforced resin composite sheet. Specifically, FIG. 6 is an image 1 second after ignition in the test pieces of each fiber reinforced resin composite sheet. As can be seen from FIG. 6, the test pieces of Example 2-1 and Example 2-2, in which the carbon fibers were impregnated from the surface of the film to the inside in approximately half of each carbon fiber, tended to be less susceptible to flame spread than the test pieces of Comparative Example 2-1 and Comparative Example 2-2, in which multiple carbon fibers were completely impregnated inside the resin film. This is thought to be because the test pieces of Example 2-1 and Example 2-2 were laminated in a state where multiple non-flammable carbon fibers were not completely impregnated and were exposed on the flame retardant resin film, suppressing the spread of flame. In this way, the fiber reinforced resin composite sheet in this embodiment is thought to have very excellent flame retardancy because not only the resin film has flame retardant properties, but also a configuration in which multiple reinforcing fibers are laminated on the flame retardant resin film.

[0152] This application is based on Japanese Patent Application No. 2020-075392, filed on April 21, 2020, the contents of which are incorporated herein by reference.

[0153] In order to express the present invention, the present invention has been described adequately and sufficiently through the embodiments and examples with reference to specific examples, but it should be recognized that those skilled in the art can easily change and / or improve the above-mentioned embodiments and examples. Therefore, unless the changes or improvements made by those skilled in the art are at a level that departs from the scope of the claims described in the claims, the changes or improvements are interpreted as being included in the scope of the claims. [Industrial Applicability]

[0154] The present invention can improve the flame retardancy, moldability, and strength under high temperature conditions of a sheet in the technical field related to fiber reinforced resin composite sheets, and can be widely used as materials for sports and leisure components, industrial components such as automobiles and aircraft, and housings and parts for electrical or electronic devices.

Claims

1. A fiber-reinforced resin composite sheet comprising: a flame-retardant resin film made of a thermoplastic resin composition having a glass transition temperature Tg of 90° C. or higher; and a plurality of carbon fibers laminated on the flame-retardant resin film in a state in which the plurality of carbon fibers are spread from a carbon fiber bundle and oriented in the same direction, The flammability classification of the flame-retardant resin film as determined in a UL94 VTM flammability test in accordance with the ASTM D4804 standard is VTM-0; The volume fraction Vf of the carbon fiber is 30% or more and 65% or less, The thickness of the fiber reinforced resin composite sheet is 20 μm or more and 80 μm or less, The flammability classification of the fiber-reinforced resin composite sheet as determined in a UL94-5V flammability test in accordance with the ASTM D5048 standard is 5V-A or 5V-B; The thermoplastic resin composition is a fiber-reinforced resin composite sheet comprising a polycarbonate resin and one or more flame retardants selected from a halogen-based flame retardant, a phosphorus-based flame retardant, a silicone-based flame retardant, and an inorganic flame retardant.

2. The fiber-reinforced resin composite sheet according to claim 1 , wherein the carbon fibers are laminated on both sides of the flame-retardant resin film.

3. The fiber reinforced resin composite sheet according to claim 1 or 2, wherein the flame retardant resin film has a thickness of 5 μm or more and 50 μm or less.

4. The thickness of the flame-retardant resin film is 5 μm or more and 40 μm or less, and the thickness of the fiber reinforced resin composite sheet is 25 μm or more and 60 μm or less. Fiber reinforced resin composite sheet according to any one of claims 1 to 3.

5. The fiber-reinforced resin composite sheet according to any one of claims 1 to 4 is a fiber-reinforced composite material in which a plurality of layers are laminated in the thickness direction, The fiber reinforced composite material is a fiber reinforced resin composite material in which the fiber directions of the carbon fibers of the multiple fiber reinforced resin composite sheets are laminated in a state where there is an angular difference in a two-dimensional direction.

6. The fiber reinforced resin composite sheet according to any one of claims 1 to 4 is a fiber reinforced composite material laminated in the thickness direction in the form of a plurality of chopped materials, The chopped material is formed so that the fiber reinforced resin composite sheet has a rectangular shape with a short side length of 2 mm or more and 50 mm or less and a long side length of 2 mm or more and 80 mm or less, The fiber reinforced composite material is a fiber reinforced resin composite material in which the fiber directions of the carbon fibers of the multiple chopped materials are layered in a two-dimensionally random manner.

7. A resin molded product comprising the fiber-reinforced resin composite material according to claim 5 or 6.

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