Base material for forming, formed article using the same, and method for producing the same

Abstract

Provided are: a molding base material characterized by having at least a fiber-reinforced resin prepreg layer, a fiber paper layer, and a partition layer interposed between the prepreg layer and the fiber paper layer; a molded product obtained by using the same; and a production method therefor. The present invention makes it possible to achieve high thermal resistance and insulation properties as well as improved overall space efficiency and weight reduction in a fiber-reinforced resin molded product.

Description

Technical Field

[0001] The present invention relates to a molding base material combining a prepreg layer of a fiber reinforced resin and a fiber paper layer, a molded article molded using the molding base material, and a method for manufacturing the molded article.

Background Art

[0002] Fiber reinforced resin molded articles are widely used in various applications by taking advantage of their characteristics of being lightweight, high-strength, and high-rigidity. In the production of fiber reinforced resin molded articles, molding is often performed using a prepreg, which is an uncured or semi-cured molding base material in which reinforcing fibers such as carbon fibers and glass fibers are impregnated with a matrix resin (for example, Patent Document 1).

[0003] Although heat resistance is sometimes required for fiber reinforced resin molded articles, the heat resistance of fiber reinforced resin molded articles is determined by the heat resistance of the matrix resin. When heat resistance is required for fiber reinforced resin molded articles, conventionally, for example, the following methods have been adopted. (1) Select a resin having high heat resistance characteristics for the matrix resin. (2) Prevent the temperature of the molded article from rising. (i) Keep a distance from a high heat source. (ii) Install a cooling device between the molded article and the high heat source (for example, forced air cooling). (iii) Incorporate a cooling mechanism directly into the molded article (for example, water cooling pipes, cooling fins). (iv) Use a heat insulating material in combination to greatly suppress heat conduction (for example, ceramic material, foam material). (v) Use a heat reflecting material in combination to greatly suppress radiant heat (for example, metal plate, metal foil).

[0004] However, any of the above methods has the following problems. In the above method (1), there is a limit to the heat resistance of the resin. In the above method (2), ·Additional costs are incurred. ·The structure becomes complicated. ·The weight increases. · Space is required.

[0005] Recently, as a heat insulating material for suppressing heat conduction in the above method (2)(iv), a synthetic resin fiber paper (fiber paper made of non-woven fabric, particularly polyimide fiber paper) has been proposed as an alternative to ceramic materials and foaming materials (for example, Patent Document 2). This polyimide fiber paper has excellent properties such as high heat insulation, high heat resistance, thinness, and light weight. That is, this polyimide fiber paper is obtained by papermaking in the same way as the method for making Japanese paper from fibers of a polyimide resin with high heat resistance or a polyimide resin film with high heat resistance that has been micro-slit and fiberized. Since it has voids (air layers between fibers) inside, it can exhibit high heat insulation performance. Such polyimide fiber paper with high heat insulation performance can be formed into a thin layer while ensuring the desired heat insulation performance compared to foaming materials (for example, Patent Document 3) that are generally widely used as heat insulating materials. Therefore, it is particularly suitable when improving space efficiency and weight reduction are required in cases where the installation space of the whole including the heat insulating material is narrow.

[0006] However, when using the above polyimide fiber paper to enhance the heat resistance and heat insulation of a fiber-reinforced resin molded product, since the fiber paper is joined to the molded product by post-construction, there are the following problems. · It takes time and effort for joining. · An adhesive or adhesive agent for joining is required. · There is a risk of peeling off from the molded product during use.

[0007] When applying the above polyimide fiber paper to a fiber-reinforced resin molded product formed using a prepreg of a fiber-reinforced resin as described above, in order to avoid post-construction having the above problems, it is conceivable to integrally mold the prepreg and the polyimide fiber paper. However, simply integrally molding these causes the following problems. That is, during the integral molding, the resin of the prepreg penetrates into the polyimide fiber paper, filling the voids inside the fiber paper (the air layer disappears or significantly decreases), and the excellent heat insulation property of the polyimide fiber paper is impaired.

Prior Art Documents

Patent Documents

[0008]

Patent Document 1

Patent Document 2

Patent Document 3

Summary of the Invention

Problems to be Solved by the Invention

[0009] Therefore, in view of the above background art, an object of the present invention is to provide a molding base material in which a prepreg of a fiber-reinforced resin and a fiber paper capable of exhibiting high heat insulation property in a thin layer are appropriately integrated without impairing the high heat insulation property of the fiber paper, in order to achieve both high heat resistance and heat insulation property of the fiber-reinforced resin molded product, and improvement in overall space efficiency and weight reduction. Also provided are a molded product obtained using the same and a method for manufacturing the molded product.

Means for Solving the Problems

[0010] In order to solve the above problems, the present invention employs the following configuration. (1) A molding base material characterized by having at least a prepreg layer of a fiber-reinforced resin, a fiber paper layer, and a partition layer interposed between the prepreg layer and the fiber paper layer. (2) The base material for molding according to (1), wherein the fiber paper layer is made of a polyimide fiber paper layer. (3) The base material for molding according to (1) or (2), wherein the prepreg layer contains carbon fiber or glass fiber as a reinforcing fiber. (4) The base material for molding according to any one of (1) to (3), wherein the matrix resin of the prepreg layer is made of a thermosetting resin. (5) The base material for molding according to any one of (1) to (4), wherein the partition layer is provided on at least one surface of the fiber paper layer, and a fiber paper layer different from the fiber paper layer is provided between the partition layer and the prepreg layer. (6) The base material for molding according to any one of (1) to (5), wherein the partition layer is made of a thermosetting resin. (7) A molded article obtained by heating and pressing the base material for molding according to any one of (1) to (6). (8) The molded article according to (7), having 30 to 90% voids in the fiber paper layer. (9) The molded article according to (7) or (8), having a glass transition temperature of 90 to 400 °C. (10) The molded article according to any one of (7) to (9), wherein the thermal conductivity of the fiber paper layer is 0.1 W / mK or less. (11) The molded article according to any one of (7) to (10), having a metal layer provided on at least one surface of the surface layer. (12) The molded article according to any one of (7) to (11), which is used for any application of an automobile, a motorcycle, an urban air mobility, an aircraft, or a satellite. (13) A manufacturing method of the molded article according to any one of (7) to (12), the manufacturing method having at least the following steps A to C. A. A step of preparing the base material for molding according to any one of (1) to (6). B. A step of shaping the base material for molding into a desired shape. C. A molding step of heating and pressing the shaped base material for molding.

Advantages of the Invention

[0011] According to the base material for molding of the present invention, the prepreg layer of the fiber reinforced resin and the fiber paper layer can be integrated via a partition layer interposed therebetween, and when the integrally formed base material for molding is molded by heating and pressurization, the intrusion of the matrix resin of the softened or melted prepreg layer into the fiber paper layer, at least into a part of the fiber paper layer, can be blocked by the partition layer, the voids between the fibers inside the fiber paper layer are prevented from being filled with the intruded resin, the presence of the air layer inside the fiber paper layer is maintained, and the excellent heat insulation property of the fiber paper layer is maintained. Therefore, when the integrally formed base material for molding is subjected to molding in this way, molding into a complex shape can be easily performed and the fiber paper can be surely prevented from peeling off from the molded product, and molding into a molded product having a desired form and high strength and high rigidity by the fiber reinforced resin becomes possible, and the fiber paper layer in which the presence of the air layer is maintained is molded into a desired form together with the prepreg layer, so that the molded product can exhibit the target high heat insulation property. Further, since the fiber paper layer can be formed into a thin layer, the molded product can also improve the space efficiency and reduce the weight as a whole including the fiber paper layer as a heat insulating material. Furthermore, when the fiber paper layer is made of a polyimide fiber paper layer having high heat resistance, the molded product can also exhibit high heat resistance.

[0012] Also, according to the method for manufacturing a molded product of the present invention, as long as the base material for molding according to the present invention as described above is prepared, through a shaping step of the base material similar to the conventional shaping using only the prepreg base material and a heating / pressurizing step of the shaped base material, a molded product having a desired high heat insulation property can be easily manufactured.

Embodiments for Carrying Out the Invention

[0013] Hereinafter, the present invention will be described in detail together with embodiments. The base material for molding according to the present invention is characterized by having at least a prepreg layer of a fiber reinforced resin, a fiber paper layer, and a partition layer interposed between the prepreg layer and the fiber paper layer. By laminating these layers, it is preferably formed into an integrated base material as the base material for molding.

[0014] The fiber-reinforced resin that constitutes the prepreg layer consists of reinforcing fibers and a matrix resin impregnated into the reinforcing fibers, and the matrix resin is in an uncured or semi-cured state (so-called B-stage state).

[0015] As the reinforcing fibers of the prepreg layer, either discontinuous fibers or continuous fibers can be used. However, when it is desired to give the fiber-reinforced resin layer of the molded product strength and rigidity above a certain level, it is preferable to use continuous reinforcing fibers. Further, when using continuous reinforcing fibers, from the viewpoint of ease of designing the strength and rigidity of the molded product, it is preferable to use continuous reinforcing fibers aligned in one direction. For example, as the prepreg layer of the fiber-reinforced resin in the molding base material according to the present invention, a single-layer fiber-reinforced resin prepreg layer composed of continuous reinforcing fibers aligned in one direction and a matrix resin, or a plurality of prepreg layers composed of continuous reinforcing fibers aligned in one direction and a matrix resin, with each layer laminated so as to have a desired reinforcing fiber orientation direction, can be adopted as the configuration of the prepreg layer of the fiber-reinforced resin of multiple layers.

[0016] The type of reinforcing fiber is not particularly limited, and examples include inorganic fibers such as carbon fibers and glass fibers, metal fibers, organic fibers, and the like. Two or more of these may be used.

[0017] Examples of carbon fibers include PAN-based carbon fibers using polyacrylonitrile (PAN) fibers as raw materials, pitch-based carbon fibers using petroleum tar or petroleum pitch as raw materials, cellulose-based carbon fibers using viscose rayon or cellulose acetate as raw materials, vapor-grown carbon fibers using hydrocarbons as raw materials, and graphitized fibers thereof. Among these carbon fibers, PAN-based carbon fibers are preferably used in terms of excellent balance between strength and elastic modulus.

[0018] Examples of glass fibers include E-glass fibers (for electrical use), C-glass fibers (for corrosion resistance), S-glass fibers, T-glass fibers (high strength, high elastic modulus), and the like.

[0019] Examples of the metal fibers include fibers made of metals such as iron, gold, silver, copper, aluminum, brass, and stainless steel.

[0020] Examples of the organic fibers include fibers made of organic materials such as aramid, polybenzoxazole (PBO), polyphenylene sulfide, polyester, polyamide, and polyethylene. Examples of the aramid fibers include para-aramid fibers having excellent strength and elastic modulus and meta-aramid fibers having excellent flame retardancy and long-term heat resistance. Examples of the para-aramid fibers include polyparaphenylene terephthalamide fibers and copolyparaphenylene-3,4'-oxydiphenylene terephthalamide fibers, and examples of the meta-aramid fibers include polymetaphenylene isophthalamide fibers. As the aramid fibers, para-aramid fibers having a higher elastic modulus than the meta-aramid fibers are preferably used.

[0021] Examples of the other inorganic fibers include fibers made of inorganic materials such as basalt, silicon carbide, and silicon nitride. Basalt fibers are obtained by fiberizing the mineral basalt and are fibers having very high heat resistance.

[0022] As the matrix resin of the prepreg layer, either a thermosetting resin or a thermoplastic resin can be used. From the viewpoints of being able to control the glass transition temperature as high as possible and easily, and when using the molded product in a high-temperature atmosphere, the molded product does not soften and can maintain its structure, and in the event of an accident, it can be carbonized, the use of a thermosetting resin is preferred.

[0023] Examples of the thermosetting resin as the matrix resin of the prepreg layer include unsaturated polyester, vinyl ester, epoxy, phenol (resole type), urea·melamine, polyimide, etc., as well as copolymers, modified products thereof, and resins obtained by blending two or more of these. Further, for example, an elastomer or a rubber component may be added to the above thermosetting resin to improve impact resistance. Among these, epoxy resin is particularly preferred from the viewpoints of the strength and rigidity of the molded product.

[0024] The thickness of the prepreg layer of the fiber-reinforced resin and the forming substrate using the same in the present invention is not particularly limited. However, considering the formability of the forming substrate, the ease of forming, and the good followability to complex shapes, it is not preferable that the forming substrate is too thick. Therefore, the thickness of the forming substrate is preferably in the range of 0.1 to 5 mm, more preferably in the range of 0.1 to 4 mm, and even more preferably in the range of 0.1 to 3 mm.

[0025] Regarding the ratio of the reinforcing fiber in the prepreg layer of the fiber-reinforced resin in the present invention, from the viewpoints of formability and mechanical properties, in the case of a unidirectional prepreg (UD prepreg), 55 to 65% by volume is preferable, and about 60% by volume is more preferable. In the case of a woven fabric prepreg, 45 to 55% by volume is preferable, and about 50% by volume is more preferable.

[0026] Regarding the fiber paper layer in the present invention, from the viewpoint of imparting heat insulation properties to the forming substrate, it is preferably a dry or wet non-woven fabric made of synthetic fibers. In particular, in order to form an appropriate air layer and have high heat insulation properties, it is preferably a fiber paper layer formed by papermaking synthetic fibers. Among them, in order to have high heat resistance as well as high heat insulation properties, it is preferable that the synthetic resin constituting the fiber paper layer is made of a polyimide resin, and it is preferable that the fiber paper layer is made of a polyimide fiber paper layer. As the polyimide fiber paper, the fiber paper proposed in Patent Document 2 described above can be used. In addition to the polyimide fiber paper proposed in Patent Document 2, for example, aramid fiber paper, polyphenylene sulfide paper, or a fiber paper obtained by co-papermaking these fibers can be used.

[0027] As for the fibrous paper used, from the viewpoint of heat insulation performance, it preferably has voids of 45 to 90% (void ratio at the stage of the base material for molding) in the fibrous paper layer, more preferably in the range of 60 to 90%, and still more preferably in the range of 70 to 90%. This void ratio is preferably maintained as much as possible even in the molded article after molding in order to ensure the high heat insulation property of the molded article after molding. As the molded article after molding, it preferably has voids of 30 to 90% (void ratio at the stage of the molded article) in the fibrous paper layer, more preferably in the range of 45 to 90%, and still more preferably in the range of 60 to 90%.

[0028] The thickness of the fibrous paper layer in the present invention is not particularly limited. However, if it is too thin, the thickness of the internal air layer will also be thin, so there is a possibility that the desired heat insulation performance cannot be obtained as a molded article. If it is too thick, since the fibrous paper layer is a layer that is not expected to essentially bear the strength and rigidity of the molded article, there is a possibility that the strength and hardness of the surface layer of the molded article will become too small. Therefore, the thickness of the fibrous paper layer is preferably in the range of 0.05 to 3.0 mm, more preferably in the range of 0.1 to 2.5 mm, and still more preferably in the range of 0.5 to 2.0 mm, both at the stage of the base material for molding and at the stage of the molded article.

[0029] A partition layer is interposed between the prepreg layer of the fiber-reinforced resin and the fiber paper layer. The interposed partition layer, in particular, when the molding base material according to the present invention is subjected to molding involving heating and pressurization, the matrix resin of the prepreg layer of the fiber-reinforced resin is heated and pressurized for molding to soften or melt, and the softened or melted matrix resin of the prepreg layer penetrates (impregnates) into the interior of the fiber paper layer, filling at least a part of the voids inside the fiber paper layer (the air layer disappears or significantly decreases), and has a function of suppressing the loss of the excellent heat insulation property of the fiber paper. That is, the partition layer in the present invention is a layer having a function of preventing the matrix resin of the prepreg layer from penetrating into at least a part of the fiber paper layer. On the other hand, when a small amount of the matrix resin of the prepreg layer partially penetrates into the fiber paper layer during molding, the prepreg layer and the fiber paper layer after molding are firmly adhered to each other, and it is possible to prevent each layer from peeling off during the use of the molded product, which is preferable. At this time, it is important that the porosity of the fiber paper layer in the molded product is at least 30%. More preferably, it is 45% or more, and still more preferably, it is 60% or more.

[0030] Therefore, as the interposed partition layer, as long as it has a function of preventing the matrix resin of the prepreg layer from penetrating into at least a part of the fiber paper layer, the material and thickness are not particularly limited. As the material of the partition layer, for example, thermosetting adhesive sheets of polyimide-based, polyamide-imide-based, epoxy-based, acrylic-based, urethane-based, polyester-based, phenol-based, urea-based, melamine-based resins, or adhesive sheets of silicone-based resins can be used. Note that an elastomer or rubber component may be added to the above thermosetting adhesive. Among these, from the viewpoint of adhesion to the prepreg, an epoxy-based resin is particularly preferable, but it is preferable to select an adhesive mainly composed of the same component as the resin component of the prepreg.

[0031] The thickness of the partition layer is not particularly limited, but if it is too thick, the heat insulation performance may deteriorate. Conversely, if it is too thin, the function of preventing the matrix resin of the prepreg layer from penetrating into at least a part of the fiber paper layer as described above may be significantly reduced. Therefore, in both the stage of the base material for molding and the stage of the molded product, a range of 0.01 to 0.1 mm is preferable, more preferably a range of 0.015 to 0.075 mm, and even more preferably a range of 0.015 to 0.05 mm.

[0032] In addition, as the partition layer interposed between the prepreg layer of the fiber-reinforced resin and the fiber paper layer, it is preferable to satisfy the following conditions. (1) Integrating the prepreg layer and the fiber paper layer (not necessarily complete integration) (2) Preventing the matrix resin of the prepreg layer from deeply penetrating into the fiber paper layer (both at the base material stage and the molding stage) (3) Preventing the gas in the voids of the fiber paper layer from deeply penetrating into the prepreg layer (both at the base material stage and the molding stage) (4) Having heat resistance equivalent to that of the lower heat resistance of the cured product of the prepreg layer or the fiber paper layer (5) Having the same degree of molding freedom as the prepreg layer and the fiber paper layer (bending, stretching, cutting, etc.)

[0033] Thus, the base material for molding according to the present invention has a basic laminated form (integrated form) of a prepreg layer of a fiber-reinforced resin, a fiber paper layer, and a partition layer interposed therebetween. In the base material for molding according to the present invention having this basic form, as more detailed specific forms, the following various forms can be adopted. (1) At the boundary between the prepreg layer and the partition layer: · The resin of the prepreg layer and the resin of the partition layer are mixed with each other, and the two layers are integrated. · The resin of the prepreg layer and the resin of the partition layer are in contact, and the two layers are integrated. (2) At the boundary between the partition layer and the fiber paper layer: · The resin of the partition layer penetrates only partially in the thickness direction from the boundary surface of the fiber paper layer, and the two layers are integrated. · The resin of the partition layer is in contact with the boundary surface of the fiber paper layer, and the two layers are integrated.

[0034] In the base material for molding according to the present invention, in addition to the above basic laminated form (integrated form), it can also be in a form provided with other layers. For example, a partition layer is provided on at least one surface of the above fiber paper layer (here, it is referred to as the first fiber paper for convenience), and a fiber paper layer different from the above fiber paper layer (here, it is referred to as the second fiber paper for convenience) is provided between the partition layer and the prepreg layer of the fiber reinforced resin. This second fiber paper preferably has high heat insulation and high heat resistance. As the second fiber paper, a polyimide fiber paper equivalent to the above can be used, or other fiber papers can also be used. As other fiber papers, for example, fiber papers made of aramid fiber paper, polyphenylene sulfide paper, ceramic fiber paper, or fiber papers obtained by mixed papermaking of these fibers can be used.

[0035] By heating and pressing the above base material for molding to form it, the prepreg layer of the fiber reinforced resin is cured to obtain a molded product according to the present invention.

[0036] In the molded product according to the present invention, in order to have the target heat insulation property, it is desirable to have voids in the range of 30 to 90%, preferably 45 to 90%, more preferably 60 to 90% in the fiber paper layer. That is, it is preferable to suppress the decrease of the porosity in the fiber paper layer of the base material for molding before molding as much as possible by the partition layer during molding, and maintain the porosity of the fiber paper layer in the molded product after molding within the above range so as to exhibit excellent heat insulation property.

[0037] Also, the glass transition temperature of the molded product after molding is desirably in the range of 90 to 400 °C, preferably 120 to 390 °C, more preferably 150 to 380 °C.

[0038] In the present invention, the thermal conductivity of the fibrous paper is 0.1 W / mK or less, preferably 0.07 W / mK or less, and more preferably 0.04 W / mK or less, when measured by the steady-state method.

[0039] Furthermore, in the molded article according to the present invention as described above, in order to add further functions, it is possible to add a specific layer, particularly to the surface. For example, it is possible to use a molded article in which a metal layer is provided on at least one surface layer. Examples of the metal layer include layers made of aluminum, silver, gold, nickel, chromium, and the like. By providing the metal layer, it becomes possible to endow the surface layer of the molded article with functions such as radiant heat reflection and electromagnetic wave shielding. When adding a specific layer to add functions, it is preferable to add and implement it after the "molding step of heating and pressing the shaped molding base material".

[0040] The molded article according to the present invention as described above can be manufactured by a manufacturing method having at least the following steps A to C. A. A step of preparing a molding base material according to the present invention as described above. B. A step of shaping the molding base material into a desired shape. C. A molding step of heating and pressing the shaped molding base material.

[0041] In the molded article using the molding base material according to the present invention, due to its high heat insulation performance, it is possible to thermally protect the surrounding components from the high-temperature heat source components (for example, around the exhaust pipe of an internal combustion engine). In addition, since the fibrous paper layer responsible for the heat insulation performance is lighter than the current heat insulation materials (glass cloth and ceramic sheet), the molded article can also be made lighter. Further, the molded base material (molded article) after molding can have both high heat insulation performance and high strength and high rigidity while being thin. Furthermore, since the molding base material can be configured to be thin, a compact heat insulation and heat-resistant structure can be realized, and combined with excellent heat insulation and heat resistance, it is possible to minimize the gap with the high-temperature source.

Example

[0042] Examples of the present invention will be described below. The materials used in the examples and the methods for measuring and evaluating the properties used in the description of the present invention are as follows.

[0043] Materials used in the examples: (1) As the prepreg of the fiber-reinforced resin, when the matrix resin type is an epoxy resin, prepreg F6343B-05P manufactured by Toray Industries, Inc. was used, and when the matrix resin is a cyanate ester resin, prepreg GG200T (T800-DT350CN) manufactured by Delta-Preg S.p.A. Uninominale was used. In these prepregs of the fiber-reinforced resin, continuous fibers of carbon fiber are used as the reinforcing fibers. (2) As the fiber paper layer, polyimide fiber paper manufactured by Toray DuPont Co., Ltd. was used. (3) As the partition layer, an epoxy-based adhesive sheet (AU type) manufactured by Arisawa Manufacturing Co., Ltd. was used.

[0044] Laminated form in the examples: · Fiber paper layer / Partition layer / Fiber paper layer / Partition layer / Fiber paper layer / Partition layer / Fiber paper layer / Partition layer / Prepreg layer of fiber-reinforced resin (Example 1) · Prepreg layer of fiber-reinforced resin / Partition layer / Fiber paper layer / Partition layer / Fiber paper layer / Partition layer / Prepreg layer of fiber-reinforced resin (Example 2) · Prepreg layer of fiber-reinforced resin / Partition layer / Fiber paper layer / Partition layer / Fiber paper layer / Partition layer / Fiber paper layer / Partition layer / Prepreg layer of fiber-reinforced resin (Example 3) · Prepreg layer of fiber-reinforced resin / Partition layer / Partition layer / Fiber paper layer / Partition layer / Fiber paper layer / Partition layer / Fiber paper layer / Partition layer / Partition layer / Prepreg layer of fiber-reinforced resin (Example 4)

[0045] (1) Glass transition temperature (after molding): The glass transition temperature of the cured portion of the prepreg layer of the fiber-reinforced resin in the molded product was measured at 5°C / min according to ASTM D7028 Modulus Tangent Intercept.

[0046] (2) Void ratio: It was obtained by the following calculation formula from the thickness, basis weight, and density at any position of the obtained fibrous paper. Void ratio (%) = [1 - (basis weight / thickness / material density)] × 100

[0047] (3) Layer thickness: The thickness (each layer thickness and the thickness of the molded product) was measured using a dial thickness gauge (FFG - 12) manufactured by Ozaki Seisakusho Co., Ltd.

[0048] (4) Heat insulation performance: Using a steady - state thermal conductivity measuring device manufactured by Advance Riko Co., Ltd., the thermal conductivity of the sample was measured in accordance with ASTM E1530 standard.

[0049] (Example 1) In advance, the base material was laminated so as to have a structure of fiber paper layer / partition layer / fiber paper layer / partition layer / fiber paper layer / partition layer / fiber paper layer, and heated at 160 °C for 60 minutes to cure the partition layer and bond the fiber paper layers together (the bonded and integrated base material is called base material 4). Then, an uncured partition layer was laminated on one surface of base material 4, and using an iron heated to 120 °C, it was bonded and laminated while maintaining a semi - cured (B - stage) state (this is called base material 5).

[0050] Next, a prepreg of a fiber - reinforced resin was placed on a flat mold and aligned along the mold. Then, on the prepreg, the semi - cured partition layer of base material 5 was made to contact the prepreg and aligned in the same shape as the mold (this is called base material 6).

[0051] Base material 6 was bagged with a sealing film together with the mold, and the inside was depressurized with a vacuum pump to produce a precursor (preform) of the molded product. Then, under the following conditions, the entire precursor of the molded product was cured in an autoclave to obtain a molded product. The glass transition temperature of the prepreg part of the obtained molded product was 130 °C.

[0052] · Curing conditions (autoclave) The entire precursor of the molded product was charged into an autoclave. Under a pressure of 5.0 bar, the temperature was raised from room temperature to 130 °C, and then held at 130 °C for 3 hours. Thereafter, after cooling to 70 °C, the entire molded product was taken out of the autoclave.

[0053] (Example 2) In advance, the base material was laminated so as to have a structure of fiber paper layer / partition layer / fiber paper layer, and the partition layer was cured by heating at 160 °C for 60 minutes to bond the fiber paper layers to each other (the bonded and integrated base material is called base material 1). Thereafter, partition layers (uncured) were laminated on both surfaces of base material 1, and using an iron heated to 120 °C, they were bonded and laminated while maintaining a semi-cured (B-stage) state (this is called base material 2).

[0054] Next, a prepreg of a fiber-reinforced resin was placed on a hat-shaped mold and aligned along the mold. Thereafter, on top of the prepreg, base material 2 was similarly aligned along the shape of the mold, and then another prepreg was placed on top of base material 2 and also aligned along the mold (this is called base material 3).

[0055] Base material 3 was bagged with a sealing film, and the inside was evacuated with a vacuum pump to produce a precursor (preform) of the molded product. Thereafter, under the following conditions, the entire precursor of the molded product was cured in an autoclave and then post-treated in an oven to obtain a molded product. The glass transition temperature of the prepreg portion of the obtained molded product was 355 °C.

[0056] · Curing conditions (autoclave) The entire precursor of the molded product was charged into an autoclave. Under a pressure of 4.0 bar, the temperature was raised from room temperature to 125 °C at a rate of 1 °C / min, and then held at 125 °C for 3 hours. Thereafter, after cooling to 70 °C at a rate of 2 °C / min, the entire molded product was taken out of the autoclave.

[0057] · Post-treatment conditions (oven) The entire molded product taken out from the autoclave was put into an oven, heated from room temperature to 125°C at a rate of 2°C / min, then heated from 125°C to 200°C at a rate of 0.3°C / min, and held at 200°C for 2 hours. Then, after cooling to 70°C at a rate of 2°C / min, the entire molded product was taken out of the oven.

[0058] (Example 3) In advance, the base material was laminated so as to have a structure of fiber paper layer / partition layer / fiber paper layer / partition layer / fiber paper layer, and heated at 160°C for 60 minutes to cure the partition layer and bond the fiber paper layers together (the bonded and integrated base material is called base material 7). Then, partition layers (uncured) were laminated on both surfaces of base material 7, and an iron heated to 120°C was used to bond and laminate while maintaining a semi-cured (B-stage) state (this is called base material 8).

[0059] Next, a prepreg of a fiber-reinforced resin was placed on a hat-shaped mold and aligned along the mold. Then, on top of the prepreg, base material 8 was similarly aligned along the shape of the mold, and then another prepreg was placed on top of base material 8 and aligned along the mold in the same way (this is called base material 9).

[0060] Base material 9 was bagged with a sealing film, and the inside was depressurized with a vacuum pump to produce a precursor (preform) of the molded product. Then, under the following conditions, the entire precursor of the molded product was cured in an autoclave and then post-treated in an oven to obtain the molded product. The glass transition temperature of the prepreg portion of the obtained molded product was 355°C.

[0061] · Curing conditions (autoclave) The entire precursor of the molded product was put into an autoclave, heated from room temperature to 125°C at a rate of 1°C / min under a pressure of 4.0 bar, and then held at 125°C for 3 hours. Then, after cooling to 70°C at a rate of 2°C / min, the entire molded product was taken out of the autoclave.

[0062] · Post-treatment conditions (oven) The entire molded product taken out from the autoclave was put into an oven, heated from room temperature to 125°C at a rate of 2°C / min, then heated from 125°C to 200°C at a rate of 0.3°C / min, and held at 200°C for 2 hours. Then, after cooling to 70°C at a rate of 2°C / min, the entire molded product was taken out of the oven.

[0063] (Example 4) In advance, the base material was laminated so as to have a structure of partition layer / fiber paper layer / partition layer / fiber paper layer / partition layer / fiber paper layer / partition layer, and heated at 160°C for 60 minutes to cure the partition layer and bond the fiber paper layers together (the bonded and integrated base material is called base material 10). Then, partition layers (uncured) were laminated on both surfaces of base material 10, and using an iron heated to 120°C, they were adhered and laminated while maintaining a semi-cured (B-stage) state (this is called base material 11).

[0064] Next, a prepreg of a fiber-reinforced resin was placed on a hat-shaped mold and aligned along the mold. Then, on top of the prepreg, base material 11 was similarly aligned along the shape of the mold, and then another prepreg was placed on top of base material 11 and aligned along the mold in the same way (this is called base material 12).

[0065] Base material 12 was bagged with a sealing film, and the inside was depressurized with a vacuum pump to produce a precursor (preform) of the molded product. Then, under the following conditions, the entire precursor of the molded product was cured in an autoclave and then post-treated in an oven to obtain the molded product. The glass transition temperature of the prepreg portion of the obtained molded product was 355°C.

[0066] · Curing conditions (autoclave) The entire precursor of the molded product was put into an autoclave, heated from room temperature to 125°C at a rate of 1°C / min under a pressure of 4.0 bar, then held at 125°C for 3 hours. Then, after cooling to 70°C at a rate of 2°C / min, the entire molded product was taken out of the autoclave.

[0067] · Post-treatment conditions (oven) The entire molded product taken out from the autoclave was put into an oven, heated from room temperature to 125°C at a rate of 2°C / min, then heated from 125°C to 200°C at a rate of 0.3°C / min, and held at 200°C for 2 hours. Thereafter, it was cooled to 70°C at a rate of 2°C / min and then the entire molded product was taken out of the oven.

[0068] (Comparative Example 1) A prepreg of a fiber-reinforced resin was placed on a flat-shaped mold and aligned along the mold. Thereafter, a fiber paper was similarly placed along the shape of the mold on the prepreg (this is referred to as substrate 13).

[0069] Substrate 13 was bagged with a sealing film together with the mold, and the inside was depressurized with a vacuum pump to produce a precursor (preform) of the molded product. Thereafter, under the following conditions, the entire precursor of the molded product was cured in an autoclave to obtain a molded product. The glass transition temperature of the prepreg portion of the obtained molded product was 130°C.

[0070] · Curing conditions (autoclave) The entire precursor of the molded product was put into an autoclave, heated from room temperature to 130°C under a pressure of 5.0 bar, and then held at 130°C for 3 hours. Thereafter, it was cooled to 70°C and then the entire molded product was taken out of the autoclave.

[0071] The obtained molded product had a void ratio of 0% in the fiber paper, so the target heat insulation performance could not be expected.

[0072] (Comparative Example 2) A prepreg of a fiber-reinforced resin was placed on a hat-shaped mold and aligned along the mold. Thereafter, substrate 11 was placed on the prepreg and similarly aligned along the shape of the mold, and then a prepreg was further placed on substrate 11 and similarly aligned along the mold (this is referred to as substrate 14).

[0073] The base material 14 was bagged together with the mold using a sealing film, and the inside was depressurized with a vacuum pump to produce a precursor (preform) of the molded product. Thereafter, the entire precursor of the molded product was cured in an autoclave under the following conditions to obtain a molded product. The glass transition temperature of the prepreg portion of the obtained molded product was 130°C.

[0074] · Curing conditions (autoclave) The entire precursor of the molded product was put into an autoclave, heated from room temperature to 130°C under a pressure of 5.0 bar, and then held at 130°C for 3 hours. Thereafter, after cooling to 70°C, the entire molded product was taken out of the autoclave.

[0075] · Post-processing A polyimide fiber paper adhesive tape obtained by coating an acrylic adhesive on separately prepared polyimide fiber paper was cut and pasted according to the shape of the above molded product to form a heat insulation layer made of polyimide fiber paper on the surface.

[0076] Although the porosity in the surface polyimide fiber paper could be maintained high, the polyimide fiber paper could not follow the curved surface shape of the molded product, resulting in lifting from the molded product and wrinkles in the fiber paper. Also, the adhesive force between the fiber paper and the molded product was unstable.

[0077] The conditions and results of each example and comparative example are summarized in Table 1.

[0078]

Table 1

[0079] (Example 5) On both surfaces of the molded product obtained in Example 2, aluminum metal was heated and melted to evaporate in a vacuum deposition apparatus, and aluminum was agglomerated and deposited on both surfaces of the molded product to attach a 50-nm deposition film, obtaining a molded product with an additional aluminum layer on the surface layer.

Industrial Applicability

[0080] The present invention can be applied to all applications that require both high strength and high rigidity characteristics of fiber-reinforced resins and high heat insulation performance of lightweight and thin-layer materials. In particular, it is suitable for various mobilities that require lightweight and compact heat insulation and heat-resistant structures, and is also suitable for members having complex shapes and the like.

Claims

1. A base material for molding, comprising at least a prepreg layer of a fiber-reinforced resin, a fiber paper layer composed of a polyimide fiber paper layer, and a partition layer interposed between the prepreg layer and the fiber paper layer.

2. The base material for molding according to Claim 1, wherein the prepreg layer contains carbon fiber or glass fiber as a reinforcing fiber.

3. The base material for molding according to Claim 1 or 2, wherein the matrix resin of the prepreg layer is a thermosetting resin.

4. The base material for molding according to any one of Claims 1 to 3, wherein the partition layer is provided on at least one surface of the fiber paper layer, and a fiber paper layer different from the fiber paper layer is provided between the partition layer and the prepreg layer.

5. The base material for molding according to any one of Claims 1 to 4, wherein the partition layer is made of a thermosetting resin.

6. A molded article obtained by heating and pressing the base material for molding according to any one of Claims 1 to 5.

7. The molded article according to Claim 6, having 30 to 90% voids in the fiber paper layer.

8. The molded article according to Claim 6 or 7, having a glass transition temperature of 90 to 400°C.

9. The molded article according to any one of Claims 6 to 8, wherein the thermal conductivity of the fiber paper layer is 0.1 W / mK or less.

10. The molded article according to any one of Claims 6 to 9, having a metal layer provided on at least one surface layer.

11. The molded article according to any one of Claims 6 to 10, used for any application of an automobile, a motorcycle, an urban air mobility, an aircraft, or a satellite.

12. A manufacturing method of the molded article according to any one of Claims 6 to 11, having at least the following steps A to C. A. A step of preparing the base material for molding according to any one of Claims 1 to 5. B. A step of shaping the base material for molding into a desired shape. C. A molding step of heating and pressing the shaped base material for molding.

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