Mold and molding method

Abstract

To provide a mold applicable to press molding such as a heat and cool method and a cold press method, and capable of manufacturing a molded article with high productivity while suppressing deterioration of quality, and a method for manufacturing a molded article using the mold.SOLUTION: In a mold 1 with a multiple structure provided with an outer mold 10, and an inner mold 20 disposed inside the outer mold 10, the outer mold 10 is provided with an upper outer mold 11 and a lower outer mold 12. A face 11a of the upper outer mold 11 facing the lower outer mold 12 is installed with a recess 13. A face 12a of the lower outer mold 12 facing the upper outer mold 11 is installed with a recess 14 and a protrusion 15. An upper inner mold 21 provided in the inner mold 20 has a shape along the face 11a of the upper outer mold 11 provided with the recess 13. A lower inner mold 22 has a shape along the face 12a of the lower outer mold 12 provided with the recess 14 and the protrusion 15.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a mold and a method for manufacturing a molded product. [Background technology]

[0002] Molded articles obtained by molding thermoplastic composite materials containing reinforcing fibers, such as prepregs, are lightweight and have excellent mechanical properties, and are therefore widely used in a variety of applications, from sports and leisure to industrial applications such as automobiles and aircraft.

[0003] Known methods for molding thermoplastic composite materials include, for example, a heat-and-cool method in which a preheated thermoplastic composite material is placed in a heated mold and cooled while applying pressure to obtain a molded product, and a cold-press method in which a preheated thermoplastic composite material is placed in a mold whose temperature is lower than the solidification temperature of the thermoplastic resin and cooled while applying pressure to obtain a molded product. These press moldings use dies that include a pair of upper and lower dies that are clamped close to each other to sandwich and pressurize the thermoplastic composite material (for example, Patent Documents 1 and 2). [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Publication No. 2020-163866 [Patent Document 2] International Publication No. 2017 / 061047 Summary of the Invention [Problem to be solved by the invention]

[0005] In both the heat-and-cool method and the cold press method, a preheated thermoplastic composite material must be quickly placed in a mold and pressed. However, press molding using conventional molds, such as those described in Patent Documents 1 and 2, requires time to align the preheated thermoplastic composite material along the molding surface of the mold, particularly when producing molded products with complex three-dimensional shapes, resulting in a long press molding time. Furthermore, it is not practical to place multiple thermoplastic composite materials in a single mold and simultaneously produce multiple molded products in a single press molding. Therefore, due to the need to ensure the quality of the molded products, the productivity of conventional molds is limited.

[0006] The present invention aims to provide a mold that can be applied to press molding such as a heat and cool method or a cold press method, and that can produce molded products with high productivity while suppressing deterioration in quality, and a method for producing molded products using the mold. [Means for solving the problem]

[0007] The present invention includes the following aspects. [1] A mold having a multi-layer structure comprising an outer mold and an inner mold disposed inside the outer mold, The outer mold comprises an upper outer mold and a lower outer mold, At least one of a recess and a protrusion is provided on a surface of the upper outer die facing the lower outer die and a surface of the lower outer die facing the upper outer die, A mold, wherein the inner mold has a shape that conforms to a surface of the outer mold on which at least one of the recessed portion and the protruding portion is provided. [2] The mold according to [1], wherein the outer mold has a heating and cooling mechanism. [3] The mold according to [1] or [2], wherein the inner mold comprises an upper inner mold and a lower inner mold. [4] The mold according to any one of [1] to [3], which is used for molding a thermoplastic resin or a thermoplastic composite material containing reinforcing fibers. [5] A method for producing a molded product using the mold according to [4], A method for manufacturing a molded product, comprising placing a molding material made of a thermoplastic resin or a thermoplastic composite material containing reinforcing fibers in the inner mold, preheating the inner mold and the molding material, placing them in the outer mold, and pressurizing them to obtain a molded product. [6] The method for producing a molded product according to [5], wherein pressure is applied while the temperature of the outer mold is lower than the temperature of the inner mold. [7] A method for manufacturing a molded product according to [5] or [6], in which a plurality of inner molds are used for one outer mold, and the inner molds are sequentially placed inside the outer mold after the molding material has been placed and preheated, and pressurized to continuously manufacture a plurality of molded products. [Effects of the Invention]

[0008] According to the present invention, it is possible to provide a mold that can be applied to press molding such as a heat and cool method or a cold press method and that can produce molded products with high productivity, and a method for producing molded products using the mold. [Brief explanation of the drawings]

[0009] [Figure 1] FIG. 1 is a cross-sectional view showing an example of a mold of the present invention. [Figure 2] FIG. 4 is a cross-sectional view showing another example of the mold of the present invention. [Figure 3] FIG. 1 is a schematic diagram showing an example of an embodiment in which a plurality of molded articles are continuously produced using the mold of the present invention. DETAILED DESCRIPTION OF THE INVENTION

[0010] [Mold] An example of the mold of the present invention will be described below with reference to the drawings. It should be noted that the dimensions of the figures illustrated in the following description are merely examples, and the present invention is not necessarily limited to them, and can be implemented with appropriate modifications within the scope that does not change the gist of the present invention.

[0011] As shown in Fig. 1, the mold 1 of this embodiment is a mold with a multi-layer structure including an outer mold 10 and an inner mold 20 disposed inside the outer mold 10. A plurality of inner molds can also be used in a stacked manner.

[0012] The outer die 10 includes an upper outer die 11 and a lower outer die 12. The upper outer die 11 and the lower outer die 12 are arranged between a pair of press platens of a press machine (not shown). The press machine moves the upper outer die 11 and the lower outer die 12 closer to or farther away from each other in the vertical direction, thereby enabling clamping and opening of the outer die 10. In the outer die 10, the lower outer die 12 may be fixed and the upper outer die 11 may be movable, or the upper outer die 11 may be fixed and the lower outer die 12 may be movable. Furthermore, both the upper outer die 11 and the lower outer die 12 may be movable.

[0013] A recess 13 is provided on a surface 11a of the upper outer mold 11 facing the lower outer mold 12. A recess 14 is provided on a surface 12a of the lower outer mold 12 facing the upper outer mold 11, and a protrusion 15 is provided that protrudes from the center of the bottom surface of the recess 14 toward the upper outer mold 11. When the outer mold 10 is viewed from the upper outer mold 11 side, the area occupied by the recessed portions 13 is smaller than the area occupied by the recessed portions 14, and the recessed portions 13 are provided so as to completely overlap the inside of the recessed portions 14. In addition, the area occupied by the protruding portions 15 is smaller than the area occupied by the recessed portions 13, and the protruding portions 15 are provided so as to completely overlap the inside of the recessed portions 13. When the outer mold 10 is clamped, a space is formed between the surface of the recessed portions 13 of the upper outer mold 11 and the surface of the protruding portions 15 of the lower outer mold 12, and this space becomes the inner mold accommodating portion 16.

[0014] The shape and dimensions of the recess 13 provided in the upper outer mold 11 are not particularly limited, and may be designed appropriately depending on the shape of the desired molded product. The shapes and dimensions of the recesses 14 and protrusions 15 provided on the lower outer mold 12 are not particularly limited, and may be designed appropriately depending on the shape of the desired molded product.

[0015] The outer mold 10 of the example shown in FIG. 1 has a heating and cooling mechanism. 1 , a plurality of heaters 30 and refrigerant flow paths 40 through which a refrigerant flows are alternately arranged inside the upper outer mold 11 along the surfaces of the recesses 13. Similarly, a plurality of heaters 30 and refrigerant flow paths 40 through which a refrigerant flows are alternately arranged inside the lower outer mold 12 along the surfaces of the recesses 14 and protrusions 15. In this way, the upper outer mold 11 and the lower outer mold 12 can be heated by the heaters 30 or cooled by circulating a refrigerant through the refrigerant flow paths 40. The heating and cooling mechanism of the outer mold 10 may be any mechanism capable of heating or cooling the molding material M through the inner mold 20, and is not limited to the embodiment shown in FIG.

[0016] The inner mold can be preheated not only by a heater inside the mold as described above, but also by external heat such as from a heating furnace. The heating furnace may be a single furnace set to the target temperature of the inner mold, or multiple furnaces whose temperature is gradually changed toward the target temperature. Using a single heating furnace can shorten the process, while using multiple heating furnaces allows the inner mold to be preheated uniformly.

[0017] The inner mold 20 of the example shown in FIG. When the inner mold 20 is placed inside the outer mold 10 , the inner mold 20 is placed in a state where it is housed in the inner mold housing portion 16 of the outer mold 10 . The inner mold 20 is not limited to the embodiment including the upper inner mold 21 and the lower inner mold 22, and may include, for example, only the lower inner mold.

[0018] The upper inner die 21 in this example is plate-shaped and has a shape that follows the surface 11a on which the recesses 13 are provided in the upper outer die 11 of the outer die 10. That is, the upper inner die 21 has a shape that looks like a metal sheet bent along the surface 11a on which the recesses 13 are provided in the upper outer die 11. The lower inner die 22 in this example is plate-shaped and has a shape that follows the surface 12a on which the recesses 14 and protrusions 15 are provided in the lower outer die 12 of the outer die 10. That is, the lower inner die 22 has a shape that looks like a metal sheet bent along the surface 12a on which the recesses 14 and protrusions 15 are provided in the lower outer die 12. The shapes of the upper inner die 21 and the lower inner die 22 are not limited to plate shapes.

[0019] When the inner mold 20 is placed in the inner mold receiving portion 16 of the outer mold 10, a molding space S is formed between the upper inner mold 21 and the lower inner mold 22. The shape of the molding space S is complementary to the shape of the desired molded product. In press molding using the mold 1, a molding material M is placed in the molding space S of the inner mold 20 and preheated, and then placed in the inner mold receiving portion 16 of the outer mold 10 and pressed by a press. This causes the molding material M to be shaped into the desired shape, and the desired molded product is obtained. The inner mold 20 does not have a heating / cooling mechanism inside, and it is preferable that the temperature is adjusted by a device capable of preheating or the outer mold 10.

[0020] Because the mold 1 has a multi-layer structure consisting of an outer mold 10 and an inner mold 20, the molding material M can be placed in the inner mold 20 and preheated in a location separate from the press and the outer mold 10. After the preheated inner mold 20 is placed in the lower outer mold 12 of the outer mold 10, the outer mold 10 can be quickly clamped and press-molded. In other words, the inner mold 20 does not occupy the press during preheating, but occupies the press only during pressure application. This reduces the time the inner mold 20 occupies the press, even if it takes time to place the molding material M along the inner mold 20. Therefore, for example, if multiple molding regions S are formed in one inner mold 20 and multiple molding materials M can be placed therein, multiple molded products can be obtained in a single press molding operation. Furthermore, if multiple inner molds 20 are prepared for one outer mold 10, the molding material M can be placed in the inner mold 20 and preheated in parallel with the press molding. The preheated inner molds 20 can then be sequentially placed on the outer mold 10, allowing for continuous press molding. Therefore, even when manufacturing molded products with complex three-dimensional shapes, molded products can be manufactured with high productivity.

[0021] Furthermore, since the lower inner die 22 of the inner die 20 has a shape that follows the surface 12a of the lower outer die 12 of the outer die 10 on which the recessed portions 14 and protruding portions 15 are provided, the distance from the surface 12a of the lower outer die 12 facing the upper outer die 11 to the molding surface 22a of the lower inner die 22 that contacts the molding material M can be made generally uniform regardless of location. Therefore, the efficiency of heat transfer from the lower outer die 12 to the molding material M via the lower inner die 22 can be made generally uniform regardless of location. The same is true for the upper inner die 21 of the inner die 20, and since the upper inner die 21 of the inner die 20 has a shape that follows the surface 11a of the upper outer die 11 of the outer die 10 on which the recessed portions 13 are provided, the distance from the surface 11a of the upper outer die 11 facing the lower outer die 12 to the molding surface 21a of the upper inner die 21 that contacts the molding material M can be made generally uniform regardless of location. Therefore, the efficiency of heat transfer from the upper outer die 11 to the molding material M via the upper inner die 21 can be made approximately uniform regardless of location. As a result, it becomes easier to adjust the temperature of the molding material M uniformly throughout during press molding, and defects such as wrinkles are less likely to occur on the surface of the molded product, making it possible to manufacture molded products with high productivity while suppressing quality degradation.

[0022] Furthermore, since the lower inner die 22 has a shape that follows the surface 12a of the outer die 10 on which the recessed portions 14 and protruding portions 15 of the lower outer die 12 are provided, when the inner die 20 is installed on the outer die 10, the inner die 20 can be easily positioned without the need for a separate positioning means such as a pin. Therefore, the work efficiency of attaching and detaching the inner die 20 to the outer die 10 during press molding is high, further increasing productivity.

[0023] Furthermore, if the inner mold 20 comprises an upper inner mold 21 and a lower inner mold 22 and the molding material M does not come into direct contact with the outer mold 10, the molding material M can be prevented from cooling rapidly even if the temperature of the outer mold 10 is low when the preheated inner mold 20 is placed on the outer mold 10. This makes it even more difficult for defects such as wrinkles to occur on the surface of the molded product, further increasing the effect of preventing quality degradation.

[0024] The thickness of the lower inner mold 22 is not limited, but is preferably approximately uniform. In terms of suppressing deformation of the inner mold due to preheating, the average thickness of the lower inner mold 22 is preferably 0.5 mm or more, more preferably 1 mm or more. In terms of cooling rate, the average thickness of the lower inner mold 22 is preferably 20 mm or less, more preferably 10 mm or less. The lower and upper limits of the average thickness of the lower inner mold 22 can be arbitrarily combined, and for example, 1 to 10 mm is preferred. The average thickness of the lower inner mold 22 means the average value of thicknesses measured at any three points on the lower inner mold 22 .

[0025] Similarly, the thickness of the upper inner mold 21 is not limited, but is preferably approximately uniform. The preferred upper and lower limits of the average thickness of the upper inner mold 21 are the same as those of the lower inner mold 22. The average thickness of the upper inner mold 21 and the average thickness of the lower inner mold 22 may be the same or different, but it is preferable that they are the same.

[0026] The material of the mold 1 is not particularly limited, and examples thereof include carbon steel, alloy tool steel containing chromium, molybdenum, tungsten, vanadium, etc. in addition to carbon, aluminum, aluminum alloy, titanium, titanium alloy, copper, and copper alloy. Among these, aluminum and aluminum alloys are preferred because of their light weight and high thermal conductivity, and aluminum alloys are particularly preferred because of their excellent rigidity. Examples of commercially available aluminum alloys include KN700 manufactured by Mitsubishi Chemical Corporation, Almigho Hard manufactured by Daido DM Solutions, and 7075 and 2017 manufactured by Hakudo Corporation. As the material for the mold 1, one type may be used alone, or two or more types may be used in combination.

[0027] In order to facilitate heat transfer from the outer mold 10 to the molding material M via the inner mold 20 and facilitate molding in a short time, the thermal conductivity of the outer mold 10 and the inner mold 20 constituting the mold 1 is preferably 5 W / m K or more, and more preferably 10 W / m K or more. There is no particular upper limit to the thermal conductivity of the outer mold 10 and the inner mold 20, and it can be, for example, 400 W / m K or less. The thermal conductivity is calculated from the thermal diffusivity, specific heat, and density measured at 100° C. in accordance with JIS H7801:95 (Method for measuring thermal diffusivity of metals by laser flash method).

[0028] [Manufacturing method for molded products] The mold of the present invention is particularly useful for molding thermoplastic resins or thermoplastic composite materials containing reinforcing fibers. An example of a method for producing a molded product using the mold of the present invention will now be described. In a method for manufacturing a molded product using the mold 1 of the example shown in Figure 1, a molding material M made of a thermoplastic resin or a thermoplastic composite material containing reinforcing fibers is placed in an inner mold 20, and the inner mold 20 and molding material M are preheated and placed in an outer mold 10, and then pressurized to obtain a molded product.

[0029] More specifically, the molding material M is placed on the lower inner mold 22 so that it somewhat conforms to the molding surface 22a thereof, and the upper inner mold 21 is placed from above to sandwich the molding material M, and then they are preheated with a preheating device. If the molding surface 22a of the lower inner mold 22 has a complex shape, the molding material M may be placed on the lower inner mold 22 and preheated, and then the molding material M may be made to conform to the molding surface 22a of the lower inner mold 22, and further preheated. In order to shorten the preheating process, the molding material M may be preheated before being poured into the inner mold.

[0030] In the present invention, the temperature of the outer mold can be set to be lower than the temperature of the inner mold, which shortens the press molding time after placing the preheated inner mold on the outer mold, thereby further improving productivity. The temperature of the inner mold after preheating can be set appropriately depending on the type of molding material, for example, whether the thermoplastic resin is an amorphous resin or a crystalline resin. From the viewpoint of moldability, the temperature of the inner mold after preheating is preferably the glass transition temperature +20°C or more for amorphous resins, the melting point +20°C or more for crystalline resins, and more preferably the glass transition temperature +30°C or more for amorphous resins, and the melting point +30°C or more for crystalline resins. From the viewpoint of preventing resin degradation, the temperature of the inner mold after preheating is preferably the resin degradation temperature −10°C or less, and more preferably the resin degradation temperature −20°C or less. The lower and upper limits of the temperature of the inner mold after preheating can be arbitrarily combined; for example, for amorphous resins, it is preferably the glass transition temperature +20°C or more, and for crystalline resins, it is preferably the melting point +20°C or more and the resin degradation temperature −20°C or less.

[0031] After preheating the inner mold 20, the preheated inner mold 20 is fitted into the recess 14 of the lower outer mold 12 of the outer mold 10 in the mold-open state, and the molding material M is pressurized by clamping the outer mold 10 with a press machine. The surface pressure applied to the molding material M during press molding can be set appropriately, for example, to about 1 to 20 MPa. The pressurizing time can be set appropriately and may be adjusted depending on the press molding method to be adopted so that the molding material M is sufficiently solidified to form a molded product.

[0032] As the press molding using the mold 1, a heat and cool method or a cold press method may be adopted. When press molding is performed using the heat-and-cool method, from the viewpoint of reducing processing time, the temperature of the outer mold 10 when the preheated inner mold 20 is placed is preferably above the glass transition temperature for amorphous resins and above the melting point for crystalline resins. For amorphous resins, the temperature is preferably at least 20°C above the glass transition temperature, and for crystalline resins, the temperature is more preferably at least 20°C above the melting point. For crystalline resins, the temperature is preferably below the glass transition temperature +180°C for amorphous resins and below the melting point +100°C for crystalline resins. For amorphous resins, the temperature is preferably below the glass transition temperature +150°C for amorphous resins and below the melting point +60°C for crystalline resins. When press molding is performed using the heat-and-cool method, the lower and upper limits of the temperature of the outer mold 10 when the preheated inner mold 20 is placed can be arbitrarily combined. For example, for amorphous resins, the temperature is preferably above the glass transition temperature but below the glass transition temperature +180°C, and for crystalline resins, the temperature is preferably above the melting point but below the melting point +100°C.

[0033] When press molding is performed using the cold press method, in order to prevent wrinkles caused by rapid cooling, the temperature of the outer mold 10 when the preheated inner mold 20 is placed is preferably above the glass transition temperature for both amorphous and crystalline resins, and more preferably above the glass transition temperature +20°C for both amorphous and crystalline resins. In terms of shortening the processing time, the temperature of the outer mold 10 when the preheated inner mold 20 is placed is preferably below the flow initiation temperature +40°C for amorphous resins and below the melting point +40°C for crystalline resins, and more preferably below the flow initiation temperature for amorphous resins and below the melting point for crystalline resins. When press molding is performed using the cold press method, the lower and upper limits of the temperature of the outer mold 10 when the preheated inner mold 20 is placed can be arbitrarily combined; for example, for amorphous resins, it is preferably above the glass transition temperature and below the flow initiation temperature, and for crystalline resins, it is preferably above the glass transition temperature and below the melting point.

[0034] In the present invention, it is preferable to use a mold having multiple inner molds for one outer mold, and to sequentially place the inner molds, after preheating them with molding material, into the outer mold and apply pressure to continuously produce multiple molded articles, thereby enabling the production of molded articles with higher productivity. In this case, for example, as shown in Fig. 2, a mold 2 may be configured in which multiple inner molds 20 can be arranged in one outer mold 10, so that multiple molded products can be obtained in one press molding. Note that the same parts in Fig. 2 as those in Fig. 1 are designated by the same reference numerals, and their explanations will be omitted.

[0035] The mode of continuously producing molded articles is not particularly limited, but an example thereof is shown in FIG. Specifically, for example, a plurality of inner molds 20 with molding material placed therein are placed on a first belt conveyor 110 and transported while being preheated in sequence in a preheating furnace 120. Then, a robot arm 130 sequentially places the preheated inner molds 20 on outer molds 10 installed in a press machine 140 for press molding. After press molding, the robot arm 130 removes the inner molds 20 from the outer mold 10 and moves them onto a second belt conveyor 150, transports them to a predetermined location, and then the inner molds 20 are opened and the molded product is taken out.

[0036] The molding material is not particularly limited, and examples thereof include thermoplastic resins and thermoplastic composite materials containing reinforcing fibers. Specific examples of the thermoplastic composite material include prepregs in which a reinforcing fiber substrate is impregnated with a thermoplastic resin, and laminates in which a reinforcing fiber substrate and a thermoplastic resin film are laminated.

[0037] Examples of reinforcing fibers include carbon fibers, glass fibers, metal fibers, and resin fibers. Of these, carbon fibers are preferred from the viewpoint of rigidity and strength. As reinforcing fibers, one type may be used alone, or two or more types may be used in combination. Examples of carbon fibers include polyacrylonitrile (PAN)-based, petroleum / coal pitch-based, rayon-based, and lignin-based.

[0038] A reinforcing fiber bundle can be formed by bundling a plurality of reinforcing fibers and applying a sizing agent thereto. The reinforcing fiber bundle is preferably a tow consisting of 3,000 to 60,000 reinforcing fibers (filaments) from the viewpoint of industrial-scale productivity and excellent mechanical properties.

[0039] In terms of facilitating the production of molded articles with excellent tensile strength, the strand strength of the reinforcing fiber bundle is preferably 4000 MPa or more, and more preferably 5000 MPa or more. In order to facilitate the development of sufficient rigidity in a molded article, the strand modulus of elasticity of the reinforcing fiber bundle is preferably 200 GPa or more, more preferably 230 GPa or more. In order to facilitate the reduction of the graphite crystal size on the surface and inside of the reinforcing fiber and the reduction of the strength in the fiber cross-sectional direction and the compressive strength in the fiber axial direction, the strand modulus of elasticity of the reinforcing fiber bundle is preferably 380 GPa or less, more preferably 350 GPa or less. The lower and upper limits of the strand modulus of elasticity of the reinforcing fiber bundle can be arbitrarily combined, and for example, 200 to 380 GPa is preferred. The strand strength and strand modulus of the reinforcing fiber bundle are measured by a method in accordance with ASTM D4018.

[0040] Examples of the form of the reinforcing fiber substrate include a unidirectional continuous fiber form in which continuous reinforcing fiber bundles are aligned in one direction, woven forms such as plain weave, twill weave, satin weave, non-crimp fabric (NCF), and three-dimensional fabric using continuous reinforcing fiber bundles, and continuous strand mats and chopped strand mats using reinforcing fiber bundles. To maintain the alignment of the fabric, fixing methods such as stitching with reinforcing fibers or welding of thermosetting resin or thermoplastic resin fibers can be applied.

[0041] The proportion of the reinforcing fibers in the reinforcing fiber substrate is preferably 80 mass % or more, more preferably 90 mass % or more, even more preferably 95 mass % or more, and particularly preferably 100 mass % based on the total mass of the reinforcing fiber substrate.

[0042] The sizing agent adhesion rate of the reinforcing fiber substrate is preferably 0.1% by mass or more, more preferably 0.2% by mass or more, so that the reinforcing fibers are sufficiently converged, fluffing is less likely to occur during the production of the molding material, and molded products with excellent mechanical properties are more likely to be obtained. The sizing agent adhesion rate of the reinforcing fiber substrate is preferably 5.0% by mass or less, more preferably 3.0% by mass or less, and even more preferably 1.5% by mass or less. The lower and upper limits of the sizing agent adhesion rate of the reinforcing fiber substrate can be arbitrarily combined, and are, for example, preferably 0.1 to 5.0% by mass, more preferably 0.2 to 3.0% by mass, and even more preferably 0.2 to 1.5% by mass.

[0043] The thermoplastic resin is not particularly limited, and examples thereof include polypropylene resin, polyamide resin, polycarbonate resin, polyphenylene sulfide resin, polyether sulfone resin, polyether imide resin, polyether ether ketone resin, and polyether ketone ketone resin. Among these, the thermoplastic resin preferably includes polyamide resin, polyphenylene sulfide resin, polyether imide resin, polyether ether ketone resin, or polyether ketone ketone resin. One type of thermoplastic resin may be used alone, or two or more types may be used in combination.

[0044] As long as the effects of the invention are not impaired, various additives such as known thermosetting resins, fillers, heat stabilizers, antioxidants, antiaging agents, flame retardants, and pigments may be contained in the thermoplastic resin as needed. The method for producing a thermoplastic composite material is not particularly limited, and may involve impregnating a molten thermoplastic resin into a reinforcing fiber substrate, or impregnating a monomer or low-molecular-weight substance that forms a thermoplastic resin into a reinforcing fiber substrate and then polymerizing the impregnated monomer or low-molecular-weight substance.

[0045] When a thermoplastic resin plate is used, the thickness of the plate is preferably 0.010 to 7 mm.

[0046] Among thermoplastic resin plates, those with particularly thin thicknesses of 0.010 to 0.50 mm are classified as films, and these films may be either unstretched or stretched films, with unstretched films being preferred from the viewpoint of excellent secondary processability. Note that unstretched films include films stretched at a ratio of less than 2.

[0047] The method for producing a thermoplastic resin plate is not particularly limited, and known methods can be used. For example, a method of molding a plate of any thickness by injection molding can be exemplified. A method in which the materials used for a particularly thin thermoplastic resin film are melt-kneaded, then extruded into a film, and cooled can be exemplified. For melt-kneading, known kneaders such as single-screw or twin-screw extruders can be used. For extrusion molding, for example, an extrusion mold such as a T-die can be used. The melt temperature can be adjusted appropriately depending on the type and mixing ratio of the resin, and the presence and type of additives. For cooling, for example, a method in which the resin is brought into contact with a cooling device such as a cooled cast roll can be exemplified.

[0048] The thermoplastic composite material may be laminated with release paper or a release film. For example, a laminate may be formed by laminating a plurality of prepregs or laminate materials, with a release paper or a release film laminated on the outermost surface. As the release film, a resin film, a metal foil, or a fluororesin film that has been subjected to a known release treatment can be used. Among the release papers and films, a polyimide film that has been subjected to a release treatment is preferred in terms of heat resistance.

[0049] From the viewpoint of ease of handling, the thickness of the molding material is preferably 0.015 mm or more, more preferably 0.040 mm or more. From the viewpoint of residual stress in the molded product, the thickness of the molding material is preferably 10 mm or less, more preferably 6.0 mm or less. The upper and lower limits of the thickness of the molding material can be arbitrarily combined, and for example, a range of 0.015 to 10.0 mm is preferred, and a range of 0.040 to 6.0 mm is more preferred.

[0050] The thickness of the molded product can be appropriately set depending on the application, and can be, for example, 0.1 to 50 mm. From the viewpoint of strength, the fiber volume content (Vf) of the molded article is preferably 20 to 75% by volume, more preferably 40 to 65% by volume.

[0051] As described above, the present invention uses a multi-layer mold for press molding, including an outer mold in which at least one of the opposing surfaces of the upper and lower outer molds is provided with a recess or a protrusion, and an inner mold having a shape that conforms to the surface of the outer mold where the recess or protrusion is provided. This allows the inner mold to be preheated in a location separate from the outer mold installed in the press, and the preheated inner mold can be quickly placed on the outer mold for press molding, thereby shortening the time the preheated inner mold occupies the press. Furthermore, it is possible to obtain multiple molded products in a single press molding operation using an inner mold that can form multiple molding regions, or to use multiple inner molds for one outer mold and sequentially place preheated inner molds on the outer mold for continuous press molding, thereby enabling the production of molded products with high productivity. Furthermore, the temperature of the molding material during press molding can be uniformly controlled throughout, reducing the likelihood of defects such as wrinkles on the surface of the molded product, thereby suppressing quality degradation.

[0052] The present invention is not limited to the embodiment using the mold 1 described above. For example, the mold of the present invention may be one in which the inner mold comprises only a lower inner mold, and molding is performed by sandwiching the molding material between the lower inner mold and the upper outer mold. In the case of a mold used in the cold press method, the outer mold may have only a cooling mechanism and may not have a heating mechanism. For example, if the press platen of the press machine has a heating / cooling mechanism, both the inner mold and the outer mold do not need to have a heating / cooling mechanism.

[0053] In addition, within the scope of the spirit of the present invention, the components in the above-described embodiments may be replaced with well-known components as appropriate, and the above-described modified examples may be combined as appropriate. [Explanation of symbols]

[0054] 1...mold, 10...outer mold, 11...upper outer mold, 12...lower outer mold, 13...recess, 14...recess, 15...convex portion, 16...inner mold accommodating portion, 20...inner mold, 21...upper inner mold, 21a...molding surface, 22...lower inner mold, 22a...molding surface, 30...heater, 40...refrigerant flow path, S...molding area, M...molding material.

Claims

1. A mold having a multi-layer structure including an outer mold and an inner mold disposed inside the outer mold, The outer mold comprises an upper outer mold and a lower outer mold, At least one of a recess and a protrusion is provided on a surface of the upper outer die facing the lower outer die and a surface of the lower outer die facing the upper outer die, The inner mold comprises an upper inner mold and a lower inner mold, the entire upper inner die has a shape that follows the surface of the upper outer die on which the recessed portion or the protruding portion is provided, A mold in which the entire lower inner mold has a shape that follows the surface of the lower outer mold on which the recessed or protruding portion is provided.

2. The mold according to claim 1 , wherein the outer mold has a heating and cooling mechanism.

3. 3. The mold according to claim 1 or 2, which is used for molding a thermoplastic resin or a thermoplastic composite material containing reinforcing fibers.

4. A method for manufacturing a molded product using the mold according to claim 3, comprising: A method for manufacturing a molded product, comprising placing a molding material made of a thermoplastic resin or a thermoplastic composite material containing reinforcing fibers in the inner mold, preheating the inner mold and the molding material, placing them in the outer mold, and pressurizing them to obtain a molded product.

5. The method for producing a molded product according to claim 4, wherein pressure is applied in a state in which the temperature of the outer mold is lower than the temperature of the inner mold.

6. 6. The method for producing a molded product according to claim 4 or 5, wherein a plurality of the inner molds are used for one of the outer molds, and the inner molds, after being preheated and having the molding material placed therein, are sequentially placed in the outer mold and pressurized, thereby continuously producing a plurality of molded products.

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