Pressing laminated body and pressed laminated body

Abstract

The present invention provides a press laminate for reducing manufacturing cost and manufacturing a metal-fiber reinforced resin composite molded product with high precision and in a short time, and a post-press laminate obtained by press molding the press laminate. The press laminate includes: a first fiber reinforced resin prepreg layer; a resin foam layer disposed on the first fiber reinforced resin prepreg; a metal layer disposed on the resin foam layer, composed of a punched metal; and a second fiber reinforced resin prepreg layer disposed on the metal layer.

Description

Technical Field

[0001] This invention relates to laminates for pressing and laminates after pressing. Background Technology

[0002] Fiber-reinforced resins, such as those made of carbon fiber, are materials that combine high strength and lightweight, and are therefore used in a variety of applications. For example, in the automotive industry, they are highly anticipated as a new material to replace steel. However, fiber-reinforced resins are currently more expensive than steel, making it difficult to use them in large quantities when the goal is to reduce product prices. Therefore, composites of metals such as steel and fiber-reinforced resins are used, thereby achieving material lightweighting and cost reduction.

[0003] As a composite material of metal and fiber-reinforced resin, for example, a honeycomb material is stamped into a honeycomb structure of a desired shape, as in the embodiment of Patent Document 1, and a fiber-reinforced resin composite material is bonded to the honeycomb structure and then heated and cured to obtain a laminate. However, there are problems such as the high cost of honeycomb material, and the fact that the fiber-reinforced resin composite material is bonded to the honeycomb material and then heated and cured to make the laminate, which makes it impossible to manufacture in a short time and incurs manufacturing costs.

[0004] Furthermore, in so-called compression molding, if a metal sheet and a fiber-reinforced resin prepreg sheet are pressed together in one go to manufacture a metal-fiber-reinforced resin composite, the difference in flexibility and thermal expansion rate between the metal and the fiber-reinforced resin will result in dimensional differences between them, making it difficult to achieve a perfect fit and failing to provide a high-quality molded product.

[0005] Existing technical documents

[0006] Patent documents

[0007] Patent Document 1: Japanese Patent Application Publication No. 2021-112849 Summary of the Invention

[0008] Therefore, the object of the present invention is to provide a laminate for pressing that reduces manufacturing costs, is lightweight, and has high molding precision.

[0009] The inventors of this invention conducted in-depth research and discovered that by using a perforated metal as the metal layer and a resin foam layer disposed between the metal layer and the fiber-reinforced resin prepreg layer, it is possible to reduce manufacturing costs and perform pressing molding with high precision. That is, this invention includes the following solution.

[0010] [1] A laminate for pressing, comprising:

[0011] First fiber-reinforced resin prepreg layer;

[0012] A resin foam layer disposed on the first fiber-reinforced resin prepreg;

[0013] A metal layer, disposed on the resin foam layer, is composed of perforated metal; and

[0014] A second fiber-reinforced resin prepreg layer is disposed on the metal layer.

[0015] [2] According to the laminated body for pressing described in [1], wherein,

[0016] The metal layer is selected from aluminum, stainless steel, copper, iron, steel, brass, nickel, and titanium.

[0017] [3] According to the laminated body for pressing described in [1], wherein,

[0018] The resins constituting the first fiber-reinforced resin prepreg layer and the second fiber-reinforced resin prepreg layer include at least one of epoxy resin, acrylic resin, phenolic resin or polyurethane resin.

[0019] [4] According to the pressing laminate described in [1], wherein,

[0020] The resin foam layer comprises a resin selected from polystyrene resin, polyurethane resin, polyolefin resin, polyethylene terephthalate resin, polyphenylene ether resin, polymethacrylamide resin, and acrylic resin.

[0021] [5] A pressed laminate, which is obtained by pressing the pressed laminate described in [1] into shape.

[0022] [6] A pressed laminate, wherein it comprises:

[0023] First fiber-reinforced resin layer;

[0024] A metal-resin composite layer disposed on the first fiber-reinforced resin layer; and

[0025] A second fiber-reinforced resin layer is disposed on the metal-resin composite layer.

[0026] The metal is made of perforated metal.

[0027] Invention Effects

[0028] By employing the pressing laminate of the present invention, it is possible to reduce manufacturing costs and manufacture lightweight pressed laminates with high precision and in a short time using a pressing method.

[0029] The metal layer of the pressed laminate of the present invention is made of a very light perforated metal, which is very light and strong. In addition, this metal layer is sandwiched together with the resin foam in a fiber-reinforced resin prepreg, and by heating and pressing, a pressed laminate in which the resin foam and the high-strength fiber-reinforced resin are integrated can be obtained.

[0030] For the pressed laminate, during pressing, at least a portion of the metal layer is embedded in the resin foam. Therefore, the contact between the metal layer and the unevenness of the fiber-reinforced resin is reduced, and adhesion is improved. Furthermore, the perforated metal is easily stretchable, and the resin foam is elastic; therefore, it is easy to mold into the desired shape using pressing. In addition, the pressed laminate of the present invention uses easily stretchable perforated metal; therefore, although wrinkles are prone to occur at the corners of the metal sheet during normal pressing processes, the present invention can obtain a pressed laminate with fewer wrinkles. Attached Figure Description

[0031] Figure 1 middle, Figure 1 The figure above is a schematic diagram of the pressing laminate 13 of the embodiment. The pressing laminate 13 is obtained by laminating the first carbon fiber reinforced resin prepreg 1, the adhesive sheet 2 (only symbols are shown because it is a thin sheet), the polyurethane resin foam 3, the mesh aluminum plate 4, the adhesive sheet 2 and the second carbon fiber reinforced resin prepreg 5. Figure 1 The figure below shows a pressing laminate 14 manufactured by heating and pressurizing the materials of the pressing laminate 14 after laminating them. The polyurethane resin foam 3 and the mesh aluminum plate 4 are composited by pressing to form a metal-polyurethane resin composite layer 6. In the pressing laminate 14, the carbon fiber reinforced prepregs 1 and 5 become fiber reinforced resin layers.

[0032] Figure 2 It represents a houndstooth pattern arranged at 60°.

[0033] Figure 3 This is a schematic diagram illustrating the overall configuration of a manufacturing apparatus for producing the pressed laminated body involved in this invention.

[0034] Figure 4A This is a schematic diagram illustrating the manufacturing process of the pressed laminate involved in this invention.

[0035] Figure 4B This is an explanation of the manufacturing process of the pressed laminate involved in the present invention. Figure 4A A schematic diagram. Detailed Implementation

[0036] [Laminated body for compression]

[0037] In this specification, the laminate for pressing is a laminate consisting of a first fiber-reinforced resin prepreg layer, a resin foam layer, a metal layer made of perforated metal, and a second fiber-reinforced resin prepreg layer made of prepreg. The resin foam layer, the metal layer, and the prepreg layer are bonded together. By heating and pressurizing the laminate for pressing, these layers are integrated to obtain the pressed laminate.

[0038] The metal constituting the metal layer can be any material that can be formed using the pressing molding of this invention, and there are no particular limitations. Various metals such as aluminum, stainless steel, copper, iron, steel, brass, nickel, and titanium can be used.

[0039] The thickness of the metal layer is not limited, but it is preferably about 0.05 to 5 mm, and more preferably 0.25 mm to 2 mm, so that it can be easily formed into the desired shape by pressing.

[0040] The metal layer is composed of perforated metal. In this specification, perforated metal refers to material obtained by processing a metal sheet with holes using a punching die. The perforated metal is manufactured by creating holes in a specified metal sheet, and the ratio of metal volume to the overall volume can be appropriately varied depending on the intended use.

[0041] In this specification, perforated metal is used instead of mesh metal for the metal layer. In the case of mesh metal, the following will explain… Figure 3 , Figure 4A , Figure 4B Such forming (forming a deep-drawn shape) is extremely difficult. Typically, the prepreg can be shaped into a diamond pattern with folded lines at the curved portion of the lower die. When using mesh metal, a uniform deep-drawn shape cannot be formed if the mesh does not form a diamond shape in the same way as the prepreg. That is, it is impossible to shape both the prepreg and the mesh simultaneously. If shaping is possible, the mesh diameter must be less than 0.25 mm and the spacing must be more than 5 mm. However, with such mesh metal, it is difficult to improve the strength of the laminate.

[0042] On the other hand, the ductility of the metal during deep drawing allows the prepreg to become rhomboid, while the round holes in the metal become elliptical, enabling it to follow the shape of the prepreg. Furthermore, the thickness of the metal layer and the diameter of the holes can be appropriately selected to improve strength, making it suitable for various applications.

[0043] Furthermore, the laminate of the present invention shortens the molding time due to the inclusion of a metal layer. Specifically, because metals such as aluminum have good thermal conductivity, heating the adhesive sheet during curing facilitates bonding, thus further increasing bond strength in a short time. During cooling, the good exothermic effect aids in the cooling of the molded body after pressing. For example, if a 0.3mm perforated metal layer is added relative to a 10mm foam thickness, a 20-second reduction in molding time is observed.

[0044] There are no particular limitations on the holes in punched metal. In deep drawing, the corner portions of the punch are usually designed with a radius of curvature R of R3 to R25 (distance radius of 3mm to 25mm). If the hole diameter is 1mm or more and 20mm or less, the spacing P2 or more, and the arrangement is a 60° houndstooth pattern, then it can correspond to the deep drawing shape. For reference, Figure 2 The image shows a houndstooth pattern arranged at 60°. Figure 2 In this diagram, D represents the hole diameter, and P represents the spacing. P2 indicates that the spacing length is 2 mm. Under these conditions, even in deep-drawn shapes, the metal layer and prepreg can be formed simultaneously in a laminated state. It should be noted that the opening ratio of the punch is preferably 10% to 50%.

[0045] In addition, the prepreg constituting the first fiber-reinforced resin prepreg layer and the second fiber-reinforced resin prepreg layer can be any sheet-like intermediate material obtained by uniformly impregnating the resin with fibrous reinforcing materials such as glass cloth or carbon fiber and heating or drying it to make it into a semi-cured state. There are no particular limitations, and fabric prepregs, unidirectional prepregs, etc. can be used.

[0046] The resin constituting the prepreg is not particularly limited; thermosetting resins, thermoplastic resins, and resin compositions comprising one of these can be used. Examples of thermosetting resins include epoxy resins, vinyl ester resins, unsaturated polyester resins, polyurethane resins, and phenolic resins, which can be used in combination. Examples of thermoplastic resins include acrylic resins, polyester resins, polycarbonate resins, polypropylene resins, polyethylene resins, polystyrene resins, vinyl chloride resins, and polyamide resins. These thermoplastic resins can be used alone or in combination.

[0047] The fibers constituting the prepreg can be glass fibers, carbon fibers, metal fibers, etc. As the fiber matrix in the fiber-reinforced resin prepreg, carbon fiber material with a thickness of 0.03 mm to 0.5 mm is preferred, but not limited to this. Furthermore, the carbon fibers constituting the prepreg can be PAN-based carbon fibers made from polyacrylonitrile, pitch-based carbon fibers made from pitch, etc. As the carbon fibers constituting the prepreg layer, PAN-based carbon fibers are preferred, but not limited to this. In addition, the fibers constituting the prepreg may also include composites such as SMC (Sheet Molding Compound), FRD (Fiber Reinforced Plastics), and GMT (Glass Reinforced Thermoplastics).

[0048] Carbon fiber is preferably woven with fibers.

[0049] The prepreg constituting the prepreg layer is preferably a fabric prepreg made of epoxy resin and carbon fiber, but is not limited thereto. It should be noted that the first fiber-reinforced resin prepreg layer and the second fiber-reinforced resin prepreg layer may be the same or different. Furthermore, the first fiber-reinforced resin prepreg layer and the second fiber-reinforced resin prepreg layer may each be composed of a single piece of prepreg, or they may be composed of multiple pieces of the same or different types of prepreg.

[0050] The first fiber-reinforced resin prepreg layer and the second fiber-reinforced resin prepreg layer preferably use rectangular prepregs with a length of 300-2000 mm and a width of 300-2000 mm independently.

[0051] The resin foam constituting the resin foam layer is not particularly limited, and any substance obtained by foaming resin can be used. Because it is a foam, it is not only lightweight but also has extremely high thermal insulation properties, making it suitable for automotive applications. Examples of resins that can be used as the resin foam include: polystyrene resin, polyurethane resin, polyolefin resin, polyethylene terephthalate resin, polyphenylene ether resin, polymethacrylamide resin, and acrylic resin. Among these, polyurethane resin is preferred from the viewpoint of elasticity and ease with which the metal layer can penetrate the resin during lamination. While polyurethane resin is sometimes slightly inferior to other resins in terms of strength, it exhibits extremely high strength when made into a sandwich-like prepreg, thus providing very high strength as a laminate.

[0052] Furthermore, when further increasing strength, polyphenylene ether resin is preferred, such as SunForce (registered trademark) manufactured by Asahi Kasei Corporation.

[0053] The resin foam is preferably flat and has a thickness of 0.7 to 10.0 mm, but is not limited thereto.

[0054] The resin foam layer and the fiber-reinforced resin prepreg layer constituting the laminate for compression bonding are bonded together using an adhesive sheet for bonding the resin foam and the prepreg. The adhesive sheet can be in sheet form. Examples of materials that serve as the adhesive component of the adhesive sheet include epoxy resin, acrylic resin, and polyurethane resin. The adhesive sheet is prepared by applying it to the fiber-reinforced resin prepreg before bonding it to the resin foam. It should be noted that a liquid adhesive can also be used instead of the adhesive sheet.

[0055] [Pressed laminate]

[0056] The pressed laminate of the present invention is manufactured by heating and pressurizing a pressed laminate, which includes: a first fiber-reinforced resin prepreg layer; a resin foam layer bonded to the first fiber-reinforced resin prepreg layer; a metal layer disposed on the resin foam layer and composed of perforated metal; and a second fiber-reinforced resin prepreg layer bonded to the metal layer and the foam layer exposed from the perforations of the metal layer.

[0057] Specifically, the pressed laminate comprises: a first fiber-reinforced resin layer, a metal-resin composite layer disposed on the first fiber-reinforced resin layer, and a second fiber-reinforced resin layer disposed on the metal-resin composite layer, wherein the metal is composed of perforated metal.

[0058] In the pressed laminate, through heating and pressurization, the metal layer becomes an integrated metal-resin composite layer with the resin layer, and the metal-resin composite layer is sandwiched by a fiber-reinforced resin layer. It should be noted that the prepreg, after pressurization and heating, is cooled to form the fiber-reinforced resin layer. For this type of pressed laminate, because a high-strength metal layer is sandwiched by a high-strength fiber-reinforced resin, the strength is very high. Furthermore, the material is lightweight and can be used as a replacement for conventional aluminum and aramid fiber honeycomb composites.

[0059] The pressed laminate can be formed into a plate shape; however, by pressing the pressed laminate, a pressed laminate with a specified shape can be formed.

[0060] [Compression molding]

[0061] In this invention, an upper mold and a lower mold are used and sandwiched between two molds to perform compression molding. The upper and lower molds can have a predetermined shape to form a molded article. For example, a protrusion can be provided on one of the pressing surfaces of the upper and lower molds, and a corresponding recess (in which the protrusion can enter) can be provided on the other. Accordingly, the pressed laminate is held by the protrusion and the recess, so the pressed laminate can have a three-dimensional shape.

[0062] In the manufacture of the laminate for pressing according to the present invention, the pressing temperature is typically 100–350°C. When the prepreg resin is a thermosetting resin, the temperature can be 120–160°C; when the prepreg resin is a thermoplastic resin, the temperature can be 230–350°C.

[0063] There is no particular limitation on the pressing pressure for forming the laminate after pressing, which is usually 0.1 to 15 MPa.

[0064] The resulting pressed laminate is made by molding fiber-reinforced resin according to its intended use and shape. It can be used for automotive parts, motorcycles, bicycles, wheelchairs, aircraft parts, flying car parts, helicopters, railway vehicle parts, ship parts, battery housings, fuel cell housings, storage battery housings, building materials, furniture (tables, wardrobes) parts, etc.

[0065] Example

[0066] The present invention will now be described in detail using examples. It should be noted that the present invention is not limited to the examples, and appropriate design changes can be made within the scope known to those skilled in the art.

[0067] [Manufacturing of Pressing Laminate 13]

[0068] First, adhesive sheets 2 are disposed on the surfaces of carbon fiber reinforced prepregs 1 and 5 to bond the carbon fiber reinforced resin prepregs 1 and 5 to the polyurethane resin foam 3. In this embodiment, an adhesive sheet containing epoxy resin is used as the adhesive sheet 2. The carbon fiber reinforced resin prepregs 1 and 5 are prepregs composed of epoxy resin and carbon fiber.

[0069] A polyurethane resin foam 3 is disposed on a carbon fiber reinforced resin prepreg 1 having adhesive sheet 2. Next, a mesh aluminum plate 4 is disposed on the polyurethane resin foam 3. A carbon fiber reinforced resin prepreg 5 having adhesive sheet 2 is disposed on the mesh aluminum plate 4. The arrangement is performed with the adhesive sheet 2 in contact with the mesh aluminum plate 4, and the arrangement is finely adjusted. The material is then gently pressed by hand to bond it using the adhesive sheet 2, resulting in a laminate 13 for pressing (see reference). Figure 1 It should be noted that when gently pressed, the polyurethane resin foam 3 passes through the holes of the mesh aluminum plate 4, and a portion of the mesh aluminum plate 4 is embedded in the polyurethane resin foam 3.

[0070] [Forming of laminated bodies for pressing]

[0071] The pressing method using a pressing machine will be explained. First, like... Figure 4AAs in (a), the pressing laminate 13 is placed on a wrinkle-removing plate 9 having a rectangular through hole. Then, the pressing laminate 13 is heated using a heater (not shown) provided inside or outside the second mold 800.

[0072] When the pressing laminate 13 is heated at 130°C, the lifting part 11 is used to raise the second mold 800 and its wrinkle-removing plate 9 to contact the first mold 700 (upper mold) (see reference). Figure 4A (b)

[0073] After the pressing laminate 13 contacts the first mold 700, the second mold 800, which has the core 8, rises further. At this time, the telescopic portion 10 contracts, thereby maintaining the position of the wrinkle-removing plate 9, and only the second mold 800 (core 8) rises further, introducing the pressing laminate 14 between the cavity 7 and the core 8, while deforming the pressing laminate 14 and rising further (see reference). Figure 4A (c)).

[0074] The core 8 enters the cavity 7 of the first mold 700, pressurizing the laminate 14, and the second mold 800 stops rising at a predetermined position. At this stopped position, heating continues to apply pressure and heat until the desired shape is achieved. The time the second mold 800 remains stationary ranges from 10 seconds to 1 hour (refer to...). Figure 4B (d)

[0075] After applying the necessary pressure and heating, heating is stopped, and the material is cooled to the specified temperature. The second mold is then lowered at 800°C to obtain the pressed laminate 14. Figure 4B (e) reference).

[0076] Symbol Explanation

[0077] 1… Carbon fiber reinforced resin prepreg

[0078] 2… Adhesive sheet

[0079] 3… Polyurethane resin foam

[0080] 4… Mesh aluminum sheet

[0081] 5… Carbon fiber reinforced resin prepreg

[0082] 6…Mesh aluminum sheet – polyurethane resin foam composite layer (metal-resin composite layer)

[0083] 7…cavity

[0084] 8… core

[0085] 9… wrinkle removal board

[0086] 10… Telescopic components

[0087] 11… Lifting section

[0088] 700…First mold

[0089] 800…Second mold

[0090] 13…Laminated bodies for pressing

[0091] 14… Pressed laminate

Claims

1. A laminated body for heat pressing, wherein, include: First fiber-reinforced resin prepreg layer; A resin foam layer disposed on the first fiber-reinforced resin prepreg; A metal layer disposed on the resin foam layer, which is composed of perforated metal, suppresses wrinkles caused by heating and pressing. as well as A second fiber-reinforced resin prepreg layer is disposed on the metal layer. The holes in the perforated metal have a diameter of 1 mm or more and less than 20 mm, a spacing of 2 mm or more, and are arranged in a 60° houndstooth pattern. The opening ratio of the perforated metal is 10-50%, and the thickness of the metal layer is 0.05-5 mm.

2. The laminated body for heating and pressing according to claim 1, wherein, The metal layer is selected from aluminum, copper, iron, steel, brass, nickel, and titanium.

3. The laminated body for heating and pressing according to claim 1, wherein, The resins constituting the first fiber-reinforced resin prepreg layer and the second fiber-reinforced resin prepreg layer include at least one of epoxy resin, acrylic resin, phenolic resin or polyurethane resin.

4. The laminated body for heating and pressing according to claim 1, wherein, The resin foam layer comprises a resin selected from polystyrene resin, polyurethane resin, polyolefin resin, polyethylene terephthalate resin, polyphenylene ether resin, polymethacrylamide resin, and acrylic resin.

5. A heat-pressed laminate, which is obtained by heat-pressing the heat-pressed laminate of claim 1.

6. A laminated body after heat pressing, wherein, have: First fiber-reinforced resin layer; A metal-resin foam composite layer is disposed on the first fiber-reinforced resin layer and includes a metal layer and a resin foam. as well as A second fiber-reinforced resin layer is disposed on the metal-resin foam composite layer. The metal layer of the metal-resin foam composite layer is made of perforated metal, which suppresses wrinkles caused by heat pressing. The holes in the perforated metal have a diameter of 1 mm or more and less than 20 mm, a spacing of 2 mm or more, and are arranged in a 60° houndstooth pattern. The opening ratio of the perforated metal is 10-50%, and the thickness of the metal layer is 0.05-5 mm.

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