Fiber-reinforced resin sheet, laminate, and molded body

Abstract

The purpose of the present invention is to provide a fiber-reinforced resin sheet that is capable of suppressing smoke generation in high-speed lay-up molding, producing a laminate having excellent appearance and physical properties by high-speed lay-up molding, and exhibiting high adhesiveness to an injection molding resin. The means for solving the problem is a fiber-reinforced resin sheet characterized by containing continuous reinforcing carbon fibers arranged in one direction and a low-crystalline or amorphous polyamide resin, the low-crystalline or amorphous polyamide resin having a melt shear viscosity of 100 Pa∙s or less at 280°C and an angular velocity of 10 rad / s.

Description

Fiber-reinforced resin sheet, laminate and molded body

[0001] The present invention relates to a fiber-reinforced resin sheet, a laminate, and a molded body.

[0002] Fiber-reinforced resin molded articles, which are produced by subjecting fiber-reinforced composite materials reinforced with continuous fibers to heat and pressure treatment and molding, are used in a variety of fields, including sports and leisure goods and aircraft materials. Traditionally, these have been produced using thermosetting resin-based carbon fiber reinforced plastics (CFRP). However, in recent years, environmental considerations have led to increased demand for easily recyclable thermoplastic resin-based carbon fiber reinforced thermoplastics (CFRTP). Melting the thermoplastic resin is essential for CFRTP processing. Layup molding, which involves additive manufacturing while welding materials using external heating by IR, lasers, hot air, and the like, has attracted attention in order to shorten processing time and produce large and complex shapes (e.g., three-dimensional shapes such as pipes).

[0003] For example, Patent Document 1 discloses a technique for adjusting the half-crystallization time of a polyamide resin made from an aliphatic diamine and terephthalic acid in order to improve resin impregnation into a reinforcing fiber substrate and interlayer adhesion.

[0004] Japanese Patent Application Laid-Open No. 2019-99603

[0005] As products obtained by the above-mentioned layup molding process continue to grow in size, even higher speeds are required. Higher speeds may result in higher energy irradiation, which may cause smoke due to resin degradation, etc. This can lead to problems such as contamination of auxiliary equipment (resulting in molding defects due to malfunctioning temperature sensors) and insufficient expression of physical properties due to poor resin impregnation into the reinforced fiber substrate and poor interlayer adhesion. Furthermore, as flanges, ribs, and the like have increasingly complex shapes, a combination of layup molding and injection molding (hybrid molding) may be required. In this case, excellent adhesion between the fiber-reinforced composite material and the injection-molded resin material is required to fully utilize the strength of the fiber-reinforced composite material. Patent Document 1 does not address these issues, and a solution to the above problems is required.

[0006] The present invention has been made in consideration of the above circumstances, and is capable of suppressing smoke generation during high-speed layup molding, producing a laminate having excellent appearance and physical properties by high-speed layup molding, and exhibiting high adhesion to injection-molded resin. An object of the present invention is to provide a fiber-reinforced resin sheet, a laminate including the fiber-reinforced resin sheet, and a molded product including the fiber-reinforced resin sheet or the laminate and an injection-molded product.

[0007] That is, the present invention is as follows.

[0008] [1] A fiber-reinforced resin sheet comprising: continuous reinforcing carbon fibers aligned in one direction; and a low-crystalline or non-crystalline polyamide resin, wherein the low-crystalline or non-crystalline polyamide resin has a melt shear viscosity of 100 Pa s or less at 280°C and an angular velocity of 10 rad / s.

[0009] [2] The fiber-reinforced resin sheet according to [1], which is in the form of a tape or sheet having a thickness of 0.25 mm or less.

[0010] [3] The fiber-reinforced resin sheet according to [1] or [2], wherein the laser absorbance / thickness value at a wavelength of 1300 nm is 20 or more.

[0011] [4] The fiber-reinforced resin sheet according to any one of [1] to [3], wherein the difference in laser transmittance between a wavelength of 1300 nm and a wavelength of 2000 nm is 0.1% or less.

[0012] [5] The fiber-reinforced resin sheet according to any one of [1] to [4], wherein the polyamide resin has a laser absorbance / thickness value of 0.05 or less at a wavelength of 1300 nm.

[0013] [6] The fiber reinforced resin sheet according to any one of [1] to [5], wherein the solidification peak width of the polyamide resin is 60 ° C. or more.

[0014] [7] A fiber-reinforced resin sheet comprising unidirectionally arranged continuous reinforcing carbon fibers and a semi-aromatic polyamide resin or a copolymer of a semi-aromatic polyamide resin and an aliphatic polyamide resin.

[0015] [8] The fiber-reinforced resin sheet according to [7], wherein the laser absorbance / thickness value at a wavelength of 1300 nm is 20 or more.

[0016] [9] The fiber-reinforced resin sheet according to [7] or [8], wherein the difference in laser transmittance at a wavelength of 1300 nm and a wavelength of 2000 nm is 0.1% or less.

[0017]

[10] A laminate comprising the fiber reinforced resin sheet according to any one of [1] to [9].

[0018]

[11] A molded product obtained by welding the fiber-reinforced resin sheet according to any one of [1] to [9] and an injection-molded product of a thermoplastic resin composition using one or more heat sources selected from the group consisting of a laser, an infrared heater, a halogen heater, a xenon lamp, hot air, and ultrasonic friction.

[12] A molded product obtained by welding the laminate according to

[10] and an injection-molded product of a thermoplastic resin composition using one or more heat sources selected from the group consisting of a laser, an infrared heater, a halogen heater, a xenon lamp, hot air, and ultrasonic friction.

[0019] According to the present invention, it is possible to provide a fiber-reinforced resin sheet that can suppress smoke generation during high-speed layup molding, can produce a laminate that is excellent in appearance and physical properties through high-speed layup molding, and can exhibit high adhesion to injection-molded resins, a laminate that includes the fiber-reinforced resin sheet, and a molded product that includes the fiber-reinforced resin sheet or the laminate and an injection-molded product.

[0020] 1A is a schematic perspective view showing a laminate including a fiber-reinforced resin sheet of an example and a comparative example. FIG. 1B is a schematic perspective view showing an injection-molded article of an example and a comparative example. FIG. 1C is a schematic perspective view showing a hybrid molded article of an example and a comparative example. MODES FOR CARRYING OUT THE INVENTION

[0021] Hereinafter, a mode for carrying out the present invention (hereinafter referred to as "the present embodiment") will be described. The following explanation of the constituent elements may be based on a representative embodiment or specific example, but the present invention is not limited to such an embodiment. In this specification, a numerical range expressed using "to" means a range that includes the numerical values ​​written before and after "to" as the lower and upper limits.

[0022] <Fiber-reinforced resin sheet> The fiber-reinforced resin sheet of this embodiment includes continuous reinforcing carbon fibers aligned in one direction, and a low-crystalline or amorphous polyamide resin, wherein the low-crystalline or amorphous polyamide resin has a melt shear viscosity of 100 Pa s or less at 280°C and an angular velocity of 10 rad / s. The fiber-reinforced resin sheet of this embodiment suppresses smoke generation during high-speed layup molding, makes it possible to produce a laminate with excellent appearance and physical properties through high-speed layup molding, and exhibits high adhesion to injection-molded resins.

[0023] The fiber-reinforced resin sheet of this embodiment includes continuous reinforcing fibers aligned in one direction and a low-crystalline or amorphous polyamide resin. The fiber-reinforced resin sheet is a resin sheet whose strength is increased by including continuous reinforcing carbon fibers. The continuous reinforcing carbon fibers are dispersed generally uniformly within the fiber-reinforced resin sheet without being aggregated in a specific position, and the spaces between the continuous reinforcing carbon fibers are filled with polyamide resin. In other words, the continuous reinforcing carbon fibers are impregnated with polyamide resin.

[0024] The size of the fiber reinforced resin sheet of this embodiment can vary depending on the size and shape of the desired laminate and molded body, but the thickness is preferably in the range of 0.05 mm to 0.25 mm. Considering the handleability of the fiber reinforced resin sheet and the impregnation of the thermoplastic resin into the continuous reinforcing fibers, the thickness of the fiber reinforced resin sheet is more preferably in the range of 0.1 mm to 0.15 mm. In one embodiment, the fiber reinforced resin sheet is preferably in the form of a tape or sheet having a thickness of 0.25 mm or less. More preferably, the fiber reinforced resin sheet is in the form of a tape or sheet having a thickness of 0.15 mm or less.

[0025] [Continuously Reinforced Carbon Fiber] The continuously reinforced carbon fiber contained in the fiber-reinforced resin sheet of the present embodiment can be any carbon fiber used in ordinary fiber-reinforced composite materials, and may be one type alone or a combination of multiple types.

[0026] (Carbon Fiber) As the carbon fiber in the continuous reinforced carbon fiber, polyacrylonitrile-based, petroleum / coal pitch-based, rayon-based, lignin-based, or other carbon fibers can be used. These carbon fibers may be used alone or in combination of two or more types. Among these carbon fibers, polyacrylonitrile-based carbon fibers are preferred from the viewpoints of productivity on an industrial scale and mechanical properties.

[0027] The surface of the continuous reinforcing carbon fiber may be coated with a surface modifier such as a coupling agent and a sizing agent, and it is preferable to change these components depending on the type of polyamide resin (matrix resin) used.

[0028] Continuously reinforced carbon fibers are typically constructed by arranging one or more reinforcing fiber bundles, each of which is formed by bundling a large number of single fibers. When one or more reinforcing fiber bundles are arranged, the total number of filaments in the continuous reinforcing fiber bundle is preferably in the range of 1,000 to 200,000. From the viewpoint of productivity, the total number of filaments in the continuously reinforced carbon fiber is more preferably 1,000 to 100,000, even more preferably 1,000 to 60,000, and particularly preferably 1,000 to 30,000. The upper limit of the total number of filaments in the continuous reinforcing fiber may be set in consideration of the balance between dispersibility and handleability, as long as good productivity, dispersibility, and handleability are maintained.

[0029] The average fiber length of the continuous reinforced carbon fibers is not particularly limited and can be various lengths depending on the desired size and shape of the fiber-reinforced resin sheet and molded body, but it is preferably longer than the length of the longest side of the molded body.

[0030] The weight of the continuous reinforced carbon fiber is 50 to 200 g / m ２ is preferable, and more preferably 90 to 150 g / m ２ is.

[0031] Each continuous reinforcing carbon fiber bundle is preferably composed of reinforcing single fibers having an average diameter (average cross-sectional diameter) of 5 to 10 μm. The average diameter of the single fibers is more preferably 6 to 8 μm. The cross-sectional shape of the single fibers is not particularly limited and may be any of circular, elliptical, irregular (e.g., Y-shaped, X-shaped, I-shaped, R-shaped, etc.), hollow, etc. The average diameter (average cross-sectional diameter) of the reinforcing carbon fibers can be measured using an optical microscope, digital microscope, scanning electron microscope (SEM), etc.

[0032] The tensile strength of the continuous reinforcing carbon fiber is preferably 3000 to 6000 MPa, more preferably 4000 to 5000 MPa. The tensile strength of the continuous reinforcing carbon fiber is calculated by the following formula: "Tensile strength of continuous reinforcing carbon fiber (MPa) = (tensile strength of single fiber (N)) / (cross-sectional area of ​​single fiber (mm ２ The tensile strength of a single fiber can be measured in accordance with JIS R 7606 using a tensile tester for single fibers.

[0033] In the fiber-reinforced resin sheet of this embodiment, the volume content of the continuous reinforcing carbon fiber is preferably in the range of 20 to 65 volume% with respect to the entire fiber-reinforced resin sheet. From the viewpoints of the strength of the fiber-reinforced resin sheet, adhesion to the resin composition for injection molding, and productivity, the volume content of the continuous reinforcing carbon fiber is more preferably in the range of 30 to 60 volume% with respect to the entire fiber-reinforced resin sheet, and particularly preferably in the range of 40 to 55 volume%. The volume content of the continuous reinforcing carbon fiber in the fiber-reinforced resin sheet can be determined by incinerating the fiber-reinforced resin sheet at a sufficiently high temperature to remove the resin component, and then calculating the ratio of the volume of the ash to the volume of the fiber-reinforced resin sheet before incineration, taking the volume of the obtained ash as the volume of the continuous reinforcing carbon fiber.

[0034] [Low-Crystalline or Non-Crystalline Polyamide Resin] The fiber-reinforced resin sheet of the present embodiment contains a low-crystalline or non-crystalline polyamide resin (hereinafter, sometimes simply referred to as "polyamide resin").

[0035] The low-crystalline or amorphous polyamide (PA) resin used in the fiber-reinforced resin sheet of this embodiment refers to the following polyamide resins. A low-crystalline polyamide resin refers to a polyamide resin whose melting point, measured with a differential scanning calorimeter (DSC) at both a heating rate and a cooling rate of 10°C / min, has a difference of 40°C or more between its melting point and its crystallization temperature during cooling. Furthermore, an amorphous polyamide resin refers to a polyamide resin whose crystallization peak is not detected in the heat flow when cooled from a molten state at 10°C / min using DSC, or whose melting peak temperature is not detected in the heat flow when heated at 20°C / min.

[0036] The type of low-crystalline or amorphous polyamide resin is not particularly limited, and polyamides made from any amino acid, lactam, or diamine and dicarboxylic acid can be used. Typical examples of amino acids include 6-aminocaproic acid, 11-aminoundecanoic acid, 12-aminododecanoic acid, and para-aminomethylbenzoic acid. Typical examples of lactams include ε-caprolactam and ω-laurolactam. Representative examples of diamines include aliphatic, alicyclic, and aromatic diamines such as tetramethylenediamine, hexamethylenediamine, 2-methylpentamethylenediamine, undecamethylenediamine, dodecamethylenediamine, 2,2,4- / 2,4,4-trimethylhexamethylenediamine, 5-methylnonamethylenediamine, metaxylylenediamine, paraxylylenediamine, 1,3-bis(aminomethyl)cyclohexane, 1,4-bis(aminomethyl)cyclohexane, 1-amino-3-aminomethyl-3,5,5-trimethylcyclohexane, bis(4-aminocyclohexyl)methane, bis(3-methyl-4-aminocyclohexyl)methane, 2,2-bis(4-aminocyclohexyl)propane, bis(aminopropyl)piperazine, and aminoethylpiperazine. Representative examples of dicarboxylic acids include aliphatic, alicyclic and aromatic dicarboxylic acids such as adipic acid, suberic acid, azelaic acid, sebacic acid, dodecanedioic acid, terephthalic acid, isophthalic acid, 2-chloroterephthalic acid, 2-methylterephthalic acid, 5-methylisophthalic acid, 5-sodiumsulfoisophthalic acid, hexahydroterephthalic acid and hexahydroisophthalic acid.

[0037] Specific examples of low-crystalline or amorphous polyamide resins include polyamide 6I (PA6I), polyamide 66 / 6I (PA66 / 6I), polyamide 6 / 6I (PA6 / 6I), polyamide 6I / 6T (PA6I / 6T), PANDT / INDT, PAMXD6 / PXD6, etc. Among these, polyamide 6I (PA6I) and polyamide 66 / 6I (PA66 / 6I) are particularly preferred.

[0038] From the viewpoint of resin impregnation and fluidity, the low-crystalline or amorphous polyamide resin (matrix resin) contained in the fiber-reinforced resin sheet has a melt shear viscosity of 100 Pa·s or less, preferably 80 Pa·s or less, and more preferably 70 Pa·s or less, at 280 ° C. and an angular velocity of 10 rad / s. When the melt shear viscosity is within the above range, the fiber-reinforced resin sheet exhibits excellent adhesion between fiber-reinforced resin sheets or between fiber-reinforced resin sheets and injection molding resin compositions during high-speed layup molding, press molding, and hybrid molding. The lower limit of the melt shear viscosity at 280 ° C. and an angular velocity of 10 rad / s is not particularly limited, but may be, for example, 10 Pa·s or more. The melt shear viscosity can be adjusted, for example, by adjusting the molecular weight, etc. In the present disclosure, the melt shear viscosity is the viscosity when shear is applied to a resin plate at a predetermined temperature, and is expressed as "melt shear viscosity = shear stress / shear rate". A detailed measurement method will be described in the Examples below. It is preferable to carry out the treatment when the moisture content in the resin has decreased to 200 ppm or less.

[0039] Furthermore, from the viewpoint of adhesion between fiber-reinforced resin sheets during high-speed layup molding, press molding, and hybrid molding, or adhesion between a fiber-reinforced resin sheet and an injection-molded resin composition (or injection-molded article), the low-crystalline or amorphous polyamide resin preferably has a heat of fusion measured by a differential scanning calorimeter (DSC) of 50 J / g or less, more preferably 40 J / g or less. In the present disclosure, the heat of fusion is the area of ​​the endothermic (melting) peak in the heat flow obtained when measured using DSC at a heating rate of 20 ° C. / min in accordance with ISO 11357-3.

[0040] Furthermore, from the viewpoint of impregnation into continuous reinforcing carbon fiber and adhesion between a fiber reinforced resin sheet or laminate and an injection molding resin composition (or injection molded article) during hybrid molding, the low crystalline or amorphous polyamide resin preferably has a solidification peak width of 50 ° C. or more, more preferably 60 ° C. or more, and even more preferably 65 ° C. or more. The upper limit of the solidification peak width is not particularly limited, but may be, for example, 120 ° C. or less. In the present disclosure, the solidification peak width is the width of the solidification peak in the heat flow obtained when the temperature is lowered from 300 ° C. to 30 ° C. at a temperature lowering rate of 10 ° C. / min in accordance with ISO11357-3 using a differential scanning calorimeter (DSC), and specifically, it can be determined by the method described in the examples described below.

[0041] The fiber-reinforced resin sheet may contain additives such as flame retardants, weather resistance improvers, antioxidants, heat stabilizers, UV absorbers, plasticizers, lubricants, colorants, compatibilizers, and conductive fillers depending on the required properties of the fiber-reinforced resin sheet to be obtained. The content of the additives is preferably 5% by mass or less relative to 100% by mass of the fiber-reinforced resin sheet. Furthermore, from the viewpoint of enhancing laser absorption, it is also possible to contain carbon-based additives such as carbon black, carbon nanotubes, and short carbon fibers. The content of the additives is preferably 10% by mass or less relative to 100% by mass of the fiber-reinforced resin sheet from the viewpoints of resin impregnation, mechanical properties, and formability of the fiber-reinforced resin sheet. The additives may be incorporated into the fiber-reinforced resin sheet by adding them to a low-crystalline or amorphous polyamide resin.

[0042] [Physical Properties of Fiber-Reinforced Resin Sheet] In the fiber-reinforced resin sheet of this embodiment, from the viewpoint of suppressing smoke generation when irradiated with a heat source such as a laser, the fiber-reinforced resin sheet preferably has a laser absorbance / thickness (μm) value at a wavelength of 1300 nm of 20 or more. The laser absorbance / thickness value of the fiber-reinforced resin sheet is more preferably 30 or more, and particularly preferably 35 or more. In addition, there is no particular upper limit to the laser absorbance / thickness value at a wavelength of 1300 nm of the fiber-reinforced resin sheet, but it is preferably 60 or less. Specifically, by having the laser absorbance / thickness value of the fiber-reinforced resin sheet within the above-mentioned range, the irradiated body such as a laser is evenly absorbed by the carbon fiber, promoting heat generation, and it is possible to weld the fiber-reinforced resin sheet and form a laminate while suppressing smoke generation due to resin deterioration. In addition, suppressing smoke generation means suppressing resin deterioration in the laminate, making it possible to obtain a molded product with excellent appearance. In addition, suppressing contamination of incidental equipment such as sensors synergistically improves the appearance of the molded product. Here, the laser absorbance can be obtained by the following method. A 40 mm square test piece is cut out from a fiber-reinforced resin sheet, and the sample is set in a film holder using a spectrophotometer (for example, a V670 spectrophotometer manufactured by JASCO Corporation), and the laser transmittance in the wavelength range of 900 nm to 2200 nm is measured. Based on the obtained results, the absorbance is calculated using the following formula: Absorbance = -log (transmittance / 100). When measuring the laser absorbance of a polyamide resin alone, which will be described later, a test piece with a thickness of 1 mm is prepared by injection molding, and measurement is carried out in the same manner as above.

[0043] The fiber-reinforced resin sheet of this embodiment can be widely applied without any restrictions on the laser wavelength to be irradiated and the type of IR heater used for heating. Therefore, the absolute value of the difference in laser transmittance between the fiber-reinforced resin sheet at wavelengths of 1300 nm and 2000 nm is preferably 0.1% or less. The difference in laser transmittance between the wavelengths of 1300 nm and 2000 nm is more preferably 0.05% or less, and particularly preferably 0.01% or less.

[0044] A fiber-reinforced resin sheet having a laser absorbance / thickness value at a wavelength of 1300 nm or a laser transmittance difference between a wavelength of 1300 nm and a wavelength of 2000 nm within a specific range can be obtained by appropriately controlling the dispersion state of the carbon fibers in the sheet. Specific control methods will be described later.

[0045] The polyamide resin used in the fiber-reinforced resin sheet of this embodiment preferably has a laser absorbance / thickness value of 0.05 or less at a wavelength of 1300 nm. The laser absorbance / thickness value of the polyamide resin at a wavelength of 1300 nm is more preferably 0.04 or less, and particularly preferably 0.03 or less. There is no particular lower limit for the laser absorbance / thickness value of the polyamide resin, but it is preferably 0.01 or more. In the method for measuring the laser absorbance of a fiber-reinforced resin sheet, a test piece having a thickness of 1 mm is prepared by injection molding, and this is used as the test piece. Measurement is performed in the same manner as above.

[0046] In another embodiment, the fiber-reinforced resin sheet is characterized by including continuous reinforcing carbon fibers aligned in one direction and a semi-aromatic polyamide resin or a copolymer of a semi-aromatic polyamide resin and an aliphatic polyamide resin.

[0047] The explanations regarding the continuous reinforcing carbon fibers and physical properties in the fiber reinforced resin sheet of the other embodiment can be cited from the explanations in [Continuous reinforcing carbon fibers] and [Physical properties of fiber reinforced resin sheet] above.

[0048] Examples of semi-aromatic polyamide resins include, but are not limited to, polyhexamethylene terephthalamide (polyamide 6T), polyhexamethylene isophthalamide (polyamide 6I), polyxylylene adipamide, polyxylylene sebacamide, polyxylylene dodecamide, polyamide 9T, polyamide 6I / 6T, etc. Note that the above-mentioned specific examples of semi-aromatic polyamide resins are merely examples, and the present invention is not limited to these.

[0049] The copolymer of a semi-aromatic polyamide resin and an aliphatic polyamide resin is not limited, but examples thereof include poly(hexamethylene terephthalamide / hexamethylene adipamide) copolymer (polyamide 6T / 66), poly(hexamethylene adipamide / hexamethylene isophthalamide) copolymer (polyamide 66 / 6I), poly(hexamethylene terephthalamide / hexamethylene sebacamide) copolymer, and the like. Examples include a copolymer of a semi-aromatic polyamide resin and an aliphatic polyamide resin (polyamide 6T / 610), a poly(hexamethylene terephthalamide / hexamethylene dodecamide) copolymer (polyamide 6T / 612), a poly(hexamethylene terephthalamide / hexamethylene isophthalamide / hexamethylene adipamide) copolymer (polyamide 6T / 6I / 66), and a poly(hexamethylene terephthalamide / caproamide) copolymer (polyamide 6T / 6). Note that the above-mentioned specific examples of copolymers of semi-aromatic polyamide resins and aliphatic polyamide resins are merely examples, and the present invention is not limited to these.

[0050] In yet another embodiment, the fiber-reinforced resin sheet comprises: continuous reinforcing carbon fibers aligned in one direction; and a low-crystalline or amorphous polyamide resin having a melt shear viscosity of 100 Pa s or less at 280°C and an angular velocity of 10 rad / s, or a semi-aromatic polyamide resin, or a copolymer of a semi-aromatic polyamide resin and an aliphatic polyamide resin. The polyamide resin, continuous reinforcing carbon fibers, and physical properties of the fiber-reinforced resin sheet of the above-mentioned further embodiment are described by citing the above-mentioned descriptions of the polyamide resin, copolymer, continuous reinforcing carbon fibers, and physical properties of the fiber-reinforced resin sheet.

[0051] (Method for Producing Fiber-Reinforced Resin Sheet) The method for producing the fiber-reinforced resin sheet of this embodiment is not particularly limited. For example, a film method is used in which continuously reinforced carbon fibers aligned in one direction (paralleled) and in a flush state are sandwiched between films of polyamide resin (matrix resin), the film-like matrix resin is heated to a molten or semi-molten state, and pressure is applied to impregnate the continuously reinforced carbon fibers with the matrix resin. Alternatively, a pultrusion method is used in which continuously reinforced carbon fibers aligned in one direction (paralleled) and in a flush state are immersed in a pool of molten matrix resin and pressure is applied to impregnate the continuously reinforced carbon fibers with the matrix resin. A thin-walled fiber-reinforced resin sheet having continuously reinforced carbon fibers aligned in one direction can be produced by continuous molding. The conditions for the pressure treatment to impregnate the continuously reinforced carbon fibers with the matrix resin are not particularly limited and can be performed under known conditions. In this case, in order to improve the impregnation of the polyamide resin with the continuously reinforced carbon fibers, it is effective to adjust the melt viscosity of the polyamide resin, control the solidification behavior, adjust the amount of terminal groups, preheat the continuously reinforced carbon fibers, select a sizing agent, etc. Furthermore, to control the laser absorbance and transmittance values ​​within the preferred ranges, it is preferable that the carbon fibers be uniformly dispersed in the fiber-reinforced resin sheet. Methods for achieving this include opening the carbon fibers before compounding, pre-impregnating the polyamide resin and carbon fibers once and then applying heat and pressure again to spread the carbon fibers in the polyamide resin, or setting a high carbon fiber content. Furthermore, when using a film-like polyamide resin, controlling the water absorption to 1000 ppm or less suppresses dimensional change in the film and enables uniform pressure application to the polyamide resin and the continuous reinforcing carbon fibers. This allows the polyamide resin to be well impregnated into the carbon fibers, and the continuous reinforcing carbon fibers to be uniformly spread and dispersed. Furthermore, steam generation during heating can be suppressed, preventing the inclusion of air, which can be a source of fracture, in the fiber-reinforced composite.

[0052] <Laminate> The laminate of the present embodiment includes the fiber-reinforced resin sheet of the present embodiment described above. Specifically, the laminate of the present embodiment includes a lay-up laminate or a press laminate obtained by lay-up molding or press molding.

[0053] [Laminate (Lay-up Molded Product) Obtained by Lay-up Molding] The laminate of this embodiment may be a lay-up laminate manufactured by, for example, heat welding the fiber-reinforced resin sheet of this embodiment using a lay-up molding machine. More specifically, the method for manufacturing the lay-up laminate of this embodiment involves, for example, setting a fiber-reinforced resin sheet slit into a tape shape of a predetermined width in the machine, and heating the tape fed to the machine head to above the melting point of the resin using a heat source such as a laser or hot air while pressing it against a work surface (jig) with an installed roller, thereby welding and shaping the tape. At this time, the jig may be heated to approximately the glass transition temperature of the fiber-reinforced resin sheet. Heating the fiber-reinforced resin sheet is affected by factors such as changes in the laser irradiation area due to the shape of the jig and changes in heating time due to the tape feed speed. Therefore, it is preferable to measure the change in surface temperature of the fiber-reinforced resin sheet in advance using a non-contact thermometer and adjust molding conditions such as output and operating speed. Furthermore, one or more tapes of a predetermined width may be set.

[0054] The heating method for welding the fiber reinforced resin sheet is not limited, but it is preferable to weld the fiber reinforced resin sheet using one or more heat sources selected from the group consisting of a laser, an infrared heater, a halogen heater, a xenon lamp, hot air, and friction caused by ultrasound, etc. That is, the laminate of this embodiment is preferably a laminate in which the fiber reinforced resin sheet is welded using one or more heat sources selected from the group consisting of a laser, an infrared heater, a halogen heater, a xenon lamp, hot air, and friction caused by ultrasound, etc.

[0055] [Laminate (Press-Molded Product) Obtained by Press Molding] The laminate of this embodiment may be a press laminate produced by, for example, a method of hot-compressing the fiber-reinforced resin sheet of this embodiment using a press molding machine. More specifically, the method for producing the press laminate of this embodiment involves, for example, cutting the sheet to a predetermined size as needed, stacking the required number of sheets in consideration of the desired product thickness, and placing them in a mold to match the mold shape. Next, after closing and clamping the mold, the mold temperature is adjusted to a temperature above the melting point of the polyamide resin contained in the fiber-reinforced resin sheet to melt the polyamide resin, and then pressurizing and shaping the polyamide resin. The mold is cooled to a temperature below the glass transition point of the polyamide resin contained in the fiber-reinforced resin sheet and then opened to obtain a laminate. The fiber-reinforced resin sheet may be cut one sheet at a time, or after stacking the desired number of sheets. The cutting method is not particularly limited, and examples include a water jet, a blade press, a hot blade press, a laser, and a plotter. The molding pressure is not particularly limited, but is preferably 2 to 6 MPa. The molding time is preferably 3 to 10 minutes after the melting point of the polyamide resin is reached.

[0056] The above-mentioned sheet and laminate may be combined with an injection molded article to form a molded article (hybrid molded article).

[0057] The molded article can be produced, for example, by welding the above-mentioned sheet or laminate to an injection-molded article produced by injection molding using a heat source. When welding a sheet to an injection-molded article, for example, a method of pressing the sheet against the injection-molded article with a roller and welding it while heating with a heat source, or a method of surrounding the injection-molded article with a sheet and welding it while heating with a heat source, can be mentioned. When welding a laminate to an injection-molded article, a method described in the examples below can be used. The injection-molded article is not particularly limited, but is preferably one molded using a resin composition described in the section (Resin composition for injection molding) below. The plasticization temperature when injecting and filling the resin composition for injection molding is preferably equal to or higher than the melting point or glass transition temperature of the resin contained in the resin composition for injection molding. More preferably, the plasticization temperature when injecting and filling the resin composition for injection molding is the melting point of the resin contained in the resin composition for injection molding + 20°C or more or the glass transition temperature of the resin contained in the resin composition for injection molding + 20°C or more, and even more preferably the melting point of the resin contained in the resin composition for injection molding + 30°C or more or the glass transition temperature of the resin contained in the resin composition for injection molding + 30°C or more.

[0058] The heating method for welding is not limited, but is preferably one or more heat sources selected from, for example, a laser, an infrared heater, a halogen heater, a xenon lamp, hot air, and ultrasonic friction. That is, the molded article of one embodiment of the present disclosure is preferably a molded article obtained by welding a fiber-reinforced resin sheet or laminate and an injection-molded article using one or more heat sources selected from the group consisting of a laser, an infrared heater, a halogen heater, a xenon lamp, hot air, ultrasonic friction, and heat transfer through a mold.

[0059] [Other Molded Articles] In another embodiment of the present disclosure, the molded article may be a molded article produced by a method in which a fiber-reinforced resin sheet of this embodiment or a laminate obtained using the fiber-reinforced resin sheet of this embodiment is placed in a mold, and then an injection molding resin composition is injected and filled to perform hybrid molding. That is, in another embodiment of the present disclosure, the molded article may be a molded article produced by overmolding the fiber-reinforced resin sheet of this embodiment or the laminate of this embodiment with an injection-molded article by insert injection molding. By insert injection molding, the injection molding resin composition flows into the details of the complex shape of the mold, and a molded article with a complex shape can be produced.

[0060] In addition to the above-described manufacturing method of the molded body, another manufacturing method of the molded body is, for example, placing the fiber-reinforced resin sheet of this embodiment or a laminate containing the fiber-reinforced resin sheet of this embodiment in a mold, closing the mold, applying pressure, and after a predetermined time, injecting and filling the resin composition for injection molding to form a molded body. The polyamide resin contained in the fiber-reinforced resin sheet or laminate and the resin composition for injection molding can be bonded. That is, a molded body can be obtained by welding the fiber-reinforced resin sheet of this embodiment or the laminate of this embodiment by overmolding with an injection-molded body by insert injection molding. By using the fiber-reinforced resin sheet of this embodiment or the laminate containing the fiber-reinforced resin sheet of this embodiment, the fiber-reinforced resin sheet or the laminate containing the fiber-reinforced resin sheet of this embodiment can be well bonded to the resin composition for injection molding without preheating, and a molded body having high mechanical properties can be obtained.

[0061] The plasticization temperature during injection filling of the injection molding resin composition is preferably equal to or higher than the melting point or glass transition temperature of the resin contained in the injection molding resin composition, more preferably equal to or higher than the melting point or glass transition temperature of the resin contained in the injection molding resin composition + 20°C, and even more preferably equal to or higher than the melting point or glass transition temperature of the resin contained in the injection molding resin composition + 30°C.

[0062] From the viewpoint of improving the adhesion between the fiber-reinforced resin sheet or laminate and the resin composition for injection molding, it is preferable to hold the resin composition for injection molding for 20 seconds to 1 minute after injection. The holding pressure at this time is preferably 20 to 40 MPa.

[0063] (Resin Composition for Injection Molding) The resin composition for injection molding in the above-mentioned molded article is not particularly limited, and a thermoplastic resin composition or a thermosetting resin composition generally used in injection molding can be used.

[0064] The thermoplastic resin contained in the resin composition for injection molding is not particularly limited, and examples thereof include polyolefin resin, polyamide resin, polyester resin, polyacetal resin, polycarbonate resin, polyether ketone, polyether ether ketone, polyether sulfone, polyphenylene sulfide, thermoplastic polyetherimide, thermoplastic fluororesin, and modified thermoplastic resins obtained by modifying these, etc. The above thermoplastic resins may be used alone or in combination.

[0065] The thermosetting resin contained in the resin composition for injection molding is not particularly limited and includes, for example, epoxy resin, thermosetting modified polyphenylene ether resin, thermosetting polyimide resin, urea resin, allyl resin, silicon resin, benzoxazine resin, phenol resin, unsaturated polyester resin, bismaleimide triazine resin, alkyd resin, furan resin, melamine resin, polyurethane resin, aniline resin, and other industrially supplied resins. The above thermosetting resins may be used alone or in combination.

[0066] The resin contained in the fiber-reinforced resin sheet and the resin contained in the resin composition for injection molding may be the same or different, but it is preferable that they are the same because this improves adhesion. That is, since the thermoplastic resin contained in the fiber-reinforced resin sheet is a polyamide resin, it is preferable that the resin contained in the resin composition for injection molding is also a polyamide resin. The content of the resin in the resin composition for injection molding is preferably 40 to 100% by mass, more preferably 50 to 70% by mass, relative to 100% by mass of the resin composition.

[0067] Depending on the required properties of the molded article to be obtained, the resin composition for injection molding may contain various fillers such as reinforcing fibers, flame retardants, weather resistance improvers, and other additives such as antioxidants, heat stabilizers, ultraviolet absorbers, plasticizers, lubricants, colorants, compatibilizers, etc. The content of the additives may be, for example, 5% by mass or less relative to 100% by mass of the resin composition.

[0068] [Method for Producing Molded Article] A method for producing a molded article in one embodiment of the present disclosure preferably includes welding the fiber-reinforced resin sheet of the present embodiment or the laminate of the present embodiment and an injection-molded article using one or more heat sources selected from the group consisting of a laser, an infrared heater, a halogen heater, a xenon lamp, hot air, and friction due to ultrasonic waves. This allows the fiber-reinforced resin sheet of the present embodiment or the laminate of the present embodiment to be welded to a previously molded injection-molded article to produce a molded article (hybrid molded article).

[0069] [Uses] A laminate including the fiber reinforced resin sheet of the present embodiment, and a molded article including the sheet or laminate can be used for parts that require high strength and rigidity, such as automobile frames, bumper face bar support materials, chassis shells, seat frames, suspension supports, sunroof frames, bumper beams, inverter cases, motorcycle frames, agricultural machinery frames, office automation equipment frames, drone housings, robot arms, and machine parts.

[0070] The present invention will be specifically explained below by showing examples, but the present invention is not limited to these examples.

[0071] The materials used in the examples and comparative examples are as follows.

[0072] <Polyamide resins> Polyamide 66 / 6I (PA66 / 6I) (synthesized by the method below) Polyamide 6I (PA6I) (synthesized by the method below) Polyamide 6 (PA6, 1013B, manufactured by UBE Corporation)

[0073] <Continuous reinforcing fibers> Carbon fiber (UTS 24K, manufactured by Teijin Limited) Glass fiber (T-425N, Nippon Electric Glass Co., Ltd.) Carbon fiber cloth: A cloth material was produced by weaving the above carbon fibers as warp and weft using a rapier loom. Glass fiber cloth: A cloth material was produced by weaving the above glass fibers as warp and weft using a rapier loom. Continuous reinforcing fibers aligned in one direction are referred to as UD, and cross materials are referred to as cloth.

[0074] The polyamide resins (PA66 / 6I and PA6I) used in the examples were produced using the following raw materials: [Raw Materials] Dicarboxylic acid adipic acid (manufactured by FUJIFILM Wako Pure Chemical Industries, Ltd.) Isophthalic acid (manufactured by FUJIFILM Wako Pure Chemical Industries, Ltd.) Diamine hexamethylenediamine (manufactured by Tokyo Chemical Industry Co., Ltd.)

[0075] (1) Synthesis of Polyamide 66 / 6I: A polyamide polymerization reaction was carried out using the "hot melt polymerization method" as follows. 1,044 g of an equimolar salt of adipic acid and hexamethylenediamine, 456 g of an equimolar salt of isophthalic acid and hexamethylenediamine, and a 0.5 mol% excess adipic acid relative to the total equimolar salt components were dissolved in 1,500 g of distilled water to prepare a 50% by mass equimolar aqueous solution of the raw material monomers. This aqueous solution was charged into an autoclave with an internal volume of 5.4 L and purged with nitrogen. While stirring at a temperature of 110-150°C, the solution was concentrated by gradually removing steam to a solution concentration of 70% by mass. The internal temperature was then raised to 220°C. At this time, the autoclave was pressurized to 1.8 MPa. The reaction was continued for 1 hour, with steam gradually removed to maintain the pressure at 1.8 MPa until the internal temperature reached 245°C. The pressure was then reduced over 1 hour. The autoclave was then vacuumed at 650 torr (86.66 kPa) for 10 minutes using a vacuum device. The final internal temperature of the polymerization was 265°C. The mixture was then pressurized with nitrogen and formed into strands from the lower spinneret (nozzle). The strands were then water-cooled, cut, and discharged as pellets. The pellets were dried at 100°C under a nitrogen atmosphere for 12 hours to obtain polyamide 66 / 6I. The resulting polyamide 66 / 6I had a weight-average molecular weight (Mw) of 28,000, a molecular weight distribution (weight-average molecular weight (Mw) / number-average molecular weight (Mn)) of 2.3, a formic acid relative viscosity (VR) of 22, a Mw / VR ratio of 1,273, and an isophthalic acid ratio of 30 mol% of the dicarboxylic acid units.

[0076] (2) Synthesis of Polyamide 6I: A polyamide polymerization reaction was carried out using the "hot melt polymerization method" as follows. 1500 g of an equimolar salt of isophthalic acid and hexamethylenediamine, and a 1.5 mol% excess adipic acid relative to the total equimolar salt components, were dissolved in 1500 g of distilled water to prepare a 50% by mass equimolar homogeneous aqueous solution of the raw material monomers. This aqueous solution was charged into an autoclave with an internal volume of 5.4 L and purged with nitrogen. While stirring at a temperature of 110-150°C, the solution was concentrated by gradually removing steam to a solution concentration of 70% by mass. The internal temperature was then raised to 220°C. At this time, the autoclave was pressurized to 1.8 MPa. The reaction was continued for 1 hour, with steam gradually removed to maintain the pressure at 1.8 MPa, until the internal temperature reached 245°C. The pressure was then reduced over 30 minutes. The autoclave was then maintained at a reduced pressure of 650 torr (86.66 kPa) for 10 minutes using a vacuum device. The final internal temperature of the polymerization was 265°C. The mixture was then pressurized with nitrogen and formed into strands from the lower spinneret (nozzle). The strands were then water-cooled, cut, and discharged as pellets. These pellets were dried at 100°C under a nitrogen atmosphere for 12 hours to obtain polyamide 6I. The resulting polyamide 6I had Mw = 20,000, Mw / Mn = 2.0, VR = 12, Mw / VR = 1667, and an isophthalic acid ratio of the dicarboxylic acid units = 100 mol%.

[0077] <Production of Polyamide Resin Film> The polyamide 66 / 6I was dehumidified and dried until its moisture content was 200 ppm or less, then fed into an extruder and melt-kneaded at a plasticizing temperature of 260°C. It was then co-extruded with low-density polyethylene (LDPE) melt-kneaded at a plasticizing temperature of 260°C through a film die at a film-forming speed of 20 m / min to form a 1250 mm wide film. While being wound around a cooling roll at 80°C, 125 mm of each end was cut off using a slitting machine, and the LDPE film was peeled off from the polyamide film, yielding a polyamide resin film 1 having a width of 1000 mm and a predetermined thickness. Polyamide resin film 2 was obtained in the same manner as the polyamide resin film 1, except that polyamide 6I was used instead of polyamide 66 / 6I. Polyamide resin film 3 was obtained in the same manner as the polyamide resin film 1, except that polyamide 6I was used instead of polyamide 66 / 6I. Since changes in film thickness due to water absorption after film formation can cause uneven pressure when integrating with carbon fiber in a subsequent process and affect the dispersibility of carbon fiber in the fiber-reinforced resin sheet, polyamide resin films 1 to 3 were stored sealed in aluminum bags to suppress water absorption. Also, a sample of polyamide resin film 1 that was left in an equilibrium water absorption state without using an aluminum bag was designated polyamide resin film 1W.

[0078] The measurement and evaluation methods used in the examples and comparative examples are as follows.

[0079] <Heat of Fusion> 10 mg of a polyamide resin sample was placed in a DSC sample container, and the sample was heated to 350°C at a rate of 20°C / min under a nitrogen flow of 40 mL / min using a DSC3500 manufactured by Netsch Japan Co., Ltd. in accordance with ISO11357-3. The area of ​​the endothermic (melting) peak in the heat flow when the sample was heated was taken as the heat of fusion (J / g).

[0080] <Solidification Peak Width> 10 mg of a polyamide resin sample was placed in a DSC sample container, and using a DSC3500 manufactured by Netsch Japan Co., Ltd., the width (°C) of the solidification peak in the heat flow was determined when the temperature was lowered from 300°C to 30°C at a temperature lowering rate of 10°C / min under a nitrogen flow of 40 mL / min in accordance with ISO11357-3.

[0081] <Melt Shear Viscosity> A polyamide resin was processed into a disk-shaped test piece with a diameter of 25 mm and a thickness of 2 mm. The test piece was previously vacuum-dried at 80°C for 24 hours to adjust the moisture content to 200 ppm or less. Using an ARES-G2 manufactured by TA Instruments, the melt shear viscosity (Pa s) at 280°C was measured in a 280°C environment with a cone-plate jig, with a gap distance of 0.05 mm and a strain amount fixed at 10%, while the angular velocity was changed from 1 to 100 rad / s.

[0082] <Absorbance> Test pieces of 40 mm square were cut out from the obtained fiber-reinforced resin sheet, and the sample was set in a film holder with an opening of 6 mm x 12 mm using a spectrophotometer V670 manufactured by JASCO Corporation, and the laser transmittance was measured in the wavelength range of 900 nm to 2200 nm. Based on the obtained results, the absorbance was calculated by back-calculation using the following formula, and the absorbance was divided by the thickness of the test piece to obtain an index. Absorbance = -log (transmittance / 100) Note that, with regard to the laser transmittance of the polyamide resin alone, a test piece of polyamide resin with a thickness of 1 mm was prepared by injection molding, and measurement was performed in the same manner as above.

[0083] <Evaluation of smoke generation> Test pieces were cut into 75 mm squares from the obtained fiber reinforced resin sheet and stacked to a thickness of 2 mm. The amount of smoke generated after 20 minutes of exposure was evaluated in accordance with the ASTM E662 smokeless test using a smoke generation tester manufactured by Fire Testing Technology. The amount of smoke generated was calculated using the following formula and divided by the number of stacked sheets to obtain an index of the amount of smoke generated per fiber reinforced resin sheet. Amount of smoke generated = chamber volume / (surface area of ​​test piece × optical path length) × log (100 / light transmittance)

[0084] <Appearance evaluation of layup laminate> A 100 mm square sample was randomly selected from the 350 mm square flat plates obtained by layup molding described below, and evaluated based on the following criteria: A: No defects B: Air bubbles or dry spots occurred C: Carbon fiber fluffing or resin dripping occurred D: Unable to mold

[0085] <Bending test> Test pieces measuring 100 mm in length parallel to the carbon fibers, 10 mm in width perpendicular to the carbon fibers, and 2 mm in thickness were cut out from a 350 mm square plate obtained by layup molding (described later), excluding 15 mm from each end. A three-point bending test was performed on the cut-out test pieces using an Instron universal testing machine, model 5582, in accordance with EN2562, at a test temperature of 23°C, a support distance of 80 mm, and a test speed of 5 mm / min, to measure the 0° bending strength (MPa) and 0° bending modulus (GPa).

[0086] <Adhesion test> A hybrid molded body prepared by the method described below was fixed to the lower jig of an Instron universal testing machine, model 5582, and the L-shaped press laminate (hereinafter sometimes referred to as "fiber reinforced resin laminate") was chucked with an upper jig at a point 40 mm from the longitudinal end of the portion not adhered to the injection molded body. Then, the upper jig was moved upward at a speed of 1 mm / min at a test temperature of 23 ° C. to peel the fiber reinforced resin laminate and the injection molded body in the hybrid molded body, and the work (J) required until the fiber reinforced resin laminate was completely peeled off was used as an index of the adhesive strength between the fiber reinforced resin laminate and the injection molded body. A: Work load of 1500 J or more regardless of the type of polyamide used in the injection molding material B: Work load of less than 1500 J depending on the type of polyamide used in the injection molding material C: Work load of less than 1500 J regardless of the type of polyamide used in the injection molding material

[0087] Example 1 (Production of fiber-reinforced resin sheet) Carbon fiber bundles spread to a width of 20 mm by an air-spreading method were fed from each reel to a sheet of 90 g / m2 fiber having a basis weight of 90 g / m2 in a horizontally flush state in close proximity to each other. ２The 25 μm thick polyamide resin film 1 prepared above was fed onto the top and bottom surfaces of the sheet, heated at 250°C, and pressurized in a semi-molten state to pre-impregnate the carbon fibers and polyamide resin. The sheet pre-impregnated with the carbon fibers and polyamide resin was then again brought to a semi-molten state and heated and pressurized at 230°C to improve the dispersibility of the carbon fibers and the impregnation of the polyamide resin. A fiber-reinforced resin sheet with a carbon fiber content of 50% by volume, a width of 1000 mm, and a thickness of 0.1 mm was obtained.

[0088] (Production of lay-up laminate) The prepared fiber-reinforced resin sheet was processed into a tape shape of 6.35 mm wide using a slitter, and eight pieces were set in a lay-up device. The roller pressure of the lay-up device head was set to 1000 N, and the feed rate was 200 mm / s. The fiber-reinforced resin sheet was irradiated and heated while adjusting the laser output so that the surface temperature was approximately 280 ° C., producing a lay-up laminate that was a flat plate of 350 mm square and 2 mm thick. During lamination, the tape gaps were positioned differently for each layer, and lamination was performed by moving each layer left and right so that the tape width overlapped by 0.5.

[0089] Example 2 A fiber reinforced resin sheet and a lay-up laminate were produced in the same manner as in Example 1, except that Polyamide Resin Film 2 was used instead of Polyamide Resin Film 1.

[0090] <Example 3> In the step of integrating the carbon fiber and the polyamide resin in Example 1, the carbon fiber was horizontally and flush with the upper and lower surfaces of the polyamide resin film 1, and the basis weight was 23 g / m ２ The mixture was heated and pressurized to obtain a fiber-reinforced resin sheet having a carbon fiber content of 50% by volume, a width of 1000 mm, and a thickness of 0.05 mm. Otherwise, a fiber-reinforced resin sheet and a lay-up laminate were produced in the same manner as in Example 1.

[0091] <Example 4> In Example 1, the thickness of the polyamide resin film 1 was 75 μm, and the basis weight of the carbon fiber was 270 g / m ２By changing the carbon fiber content to 50% by volume, a fiber reinforced resin sheet having a width of 1000 mm and a thickness of 0.3 mm was obtained. Otherwise, a fiber reinforced resin sheet and a lay-up laminate were produced in the same manner as in Example 1.

[0092] Example 5 A fiber reinforced resin sheet and a lay-up laminate were produced in the same manner as in Example 1, except that Polyamide Resin Film 1W was used instead of Polyamide Resin Film 1.

[0093] Example 6 A fiber-reinforced resin sheet and a lay-up laminate were produced in the same manner as in Example 1, except that carbon fibers that had not been subjected to the fiber-opening process were used.

[0094] Example 7 A fiber-reinforced resin sheet having a carbon fiber content of 50% by volume, a width of 1000 mm and a thickness of 0.1 mm was obtained by integrating the carbon fiber and the polyamide resin film 1 in one step without going through the pre-impregnation step in Example 1. A fiber-reinforced resin sheet and a lay-up laminate were produced in the same manner as in Example 1 except for the above.

[0095] Comparative Example 1 A fiber reinforced resin sheet and a lay-up laminate were produced in the same manner as in Example 1, except that Polyamide Resin Film 3 was used.

[0096] <Comparative Example 2> Glass fiber was used instead of carbon fiber, and the weight per unit area was 260 g / m ２ The same procedure as in Example 1 was carried out except that the glass fiber content was 50% by volume, and the laminate was aligned so that the thickness was 1000 mm and integrated with a 50 μm thick polyamide resin film 1. A fiber-reinforced resin sheet and a lay-up laminate having a width of 1000 mm and a thickness of 0.2 mm were produced.

[0097] Comparative Example 3 A fiber reinforced resin sheet and a lay-up laminate were produced in the same manner as in Comparative Example 2, except that Polyamide Resin Film 2 was used instead of Polyamide Resin Film 1.

[0098] <Comparative Example 4> A fiber having a basis weight of 90 g / m instead of carbon fiber ２ A fiber reinforced resin sheet and a lay-up laminate were produced in the same manner as in Example 1, except that the carbon fiber cloth material was integrated with the polyamide resin film 1.

[0099] <Comparative Example 5> A fiber having a basis weight of 260 g / m instead of glass fiber ２ A fiber reinforced resin sheet and a lay-up laminate were produced in the same manner as in Comparative Example 2, except that the glass fiber cloth material was used.

[0100] <Preparation of Hybrid Molded Article> A hybrid molded article was prepared using the press laminate prepared by the following method using the fiber-reinforced resin sheets of Example 1, Example 2, and Comparative Example 1 and the following resin composition for injection molding, as follows. Then, using the above-mentioned method, the adhesion with the injection-molded resin material during hybrid molding was evaluated.

[0101] [Resin compositions for injection molding] Polyamide 66 (PA66) + glass fiber (GF) (Leona 14G33 manufactured by Asahi Kasei Corporation) Polyamide 66 / 6I (PA66 / 6I) + glass fiber (GF) (Leona 90G33 manufactured by Asahi Kasei Corporation) Polyamide 6 (PA6) + glass fiber (GF) (1015GU6 manufactured by UBE Corporation)

[0102] (Production of press laminate) Press molding of a fiber-reinforced resin sheet was carried out using a ZENformer 100t press molding machine manufactured by Electric Discharge Precision Processing Laboratory Co., Ltd. Thomson punching was performed on the fiber-reinforced resin sheet to a size of 180 mm in length in the direction in which the reinforcing fibers extend and 40 mm in width in the direction perpendicular to the reinforcing fibers, and 20 sheets were obtained. The 20 punched sheets were stacked so as to have a thickness of 2 mm and set in an L-shaped press mold heated to 80 ° C. After clamping the press molding machine, the press mold temperature was increased at 60 ° C. / min to 280 ° C., and the polyamide resin (matrix resin) was left to stand for 3 minutes until it was sufficiently melted. Thereafter, the press mold temperature was kept at 280 ° C. for 5 minutes, and a pressure of 5 ton was applied, and then the pressure was increased to 10 ton, and the press mold was cooled to 80 ° C. at 60 ° C. / min to obtain an L-shaped press laminate (length 90 mm + 90 mm, width 40 mm, thickness 2 mm).

[0103] (Production of Hybrid Molded Articles) Hybrid molding was performed using an injection molding machine SE130D manufactured by Sumitomo Heavy Industries, Ltd., using samples prepared by the following method for each of the three types of injection molding resin compositions. The plasticization temperature was set to 300°C, and the injection molding resin composition was injected and filled and held at a holding pressure of 30 MPa for 30 seconds to obtain an injection molded article (length 160 mm, width 80 mm, thickness 5 mm, see FIG. 1B). 15 mm lengths were cut off from both ends of the L-shaped press laminate obtained above in the longitudinal direction (see FIG. 1A) and inserted into a jig heated to 80°C. The injection molded article obtained above was inserted into the opposite side of the jig heated to 80°C. Thereafter, the L-shaped press laminate fixed to the jig was irradiated and heated using an infrared heater while adjusting the output so that the surface temperature reached 280°C. After that, both jigs were closed under a pressure of 5 MPa for 90 seconds to obtain a hybrid molded body (see Figure 1C) in which the fiber-reinforced resin molded body (press laminate) and the injection-molded body were integrated.

[0104] The measurement results of each physical property are shown in Table 1.

[0105]

[0106] From Table 1, it can be seen that the fiber reinforced resin sheet of this embodiment can suppress smoking during high-speed layup molding, and can produce a laminate having excellent appearance and physical properties by high-speed layup molding. It can also be seen that it exhibits high adhesion to injection-molded resins.

[0107] The fiber-reinforced resin sheet of the present invention can exhibit high adhesion to injection-molded resins without preheating and can exhibit high mechanical properties, so it can be suitably used for producing hybrid molded articles. Furthermore, laminates and hybrid molded articles containing the fiber-reinforced resin sheet of the present invention have excellent mechanical properties and are therefore suitable for use in various parts requiring high strength and rigidity, such as automobile parts, aircraft parts, railway parts, construction machinery parts, agricultural machinery parts, robot parts, and office equipment parts.

Claims

1. A fiber-reinforced resin sheet comprising: continuous reinforcing carbon fibers aligned in one direction; and a low-crystalline or amorphous polyamide resin, wherein the low-crystalline or amorphous polyamide resin has a melt shear viscosity of 100 Pa·s or less at 280°C and an angular velocity of 10 rad / s.

2. The fiber-reinforced resin sheet according to claim 1, which is in the form of a tape or sheet having a thickness of 0.25 mm or less.

3. The fiber-reinforced resin sheet according to claim 1, wherein the laser absorbance / thickness value at a wavelength of 1300 nm is 20 or more.

4. The fiber-reinforced resin sheet according to claim 1, wherein the difference in laser transmittance between wavelengths of 1300 nm and 2000 nm is 0.1% or less.

5. The fiber-reinforced resin sheet according to claim 1, wherein the polyamide resin has a laser absorbance / thickness value of 0.05 or less at a wavelength of 1300 nm.

6. The fiber-reinforced resin sheet according to claim 1, wherein the polyamide resin has a solidification peak width of 60°C or more.

7. A fiber-reinforced resin sheet comprising unidirectionally arranged continuous reinforcing carbon fibers and a semi-aromatic polyamide resin or a copolymer of a semi-aromatic polyamide resin and an aliphatic polyamide resin.

8. The fiber-reinforced resin sheet according to claim 7, wherein the laser absorbance / thickness value at a wavelength of 1300 nm is 20 or more.

9. The fiber-reinforced resin sheet according to claim 7, wherein the difference in laser transmittance between wavelengths of 1300 nm and 2000 nm is 0.1% or less.

10. A laminate comprising the fiber-reinforced resin sheet according to any one of claims 1 to 9.

11. A molded article obtained by welding the fiber-reinforced resin sheet according to any one of claims 1 to 9 and an injection-molded article of a thermoplastic resin composition using one or more heat sources selected from the group consisting of laser, infrared heater, halogen heater, xenon lamp, hot air, and ultrasonic friction.

12. A molded article obtained by welding the laminate according to claim 10 and an injection-molded article of a thermoplastic resin composition using one or more heat sources selected from the group consisting of laser, infrared heater, halogen heater, xenon lamp, hot air, and ultrasonic friction.

Images