JP3834628B2 - Resin filler for manufacturing fiber reinforced composite material and fiber reinforced composite material manufacturing method using the same - Google Patents

Description

【００２１】
未硬化樹脂フィルム５は、２枚のポリイミドフィルム３，４間に充填の後、融着フィルムによってポリイミドフィルム３，４の周囲部を融着して融着部６とすることにより、未硬化樹脂フィルム５を充填した内部が封止されている。ここで、一方のポリイミドフィルム３には、直径φ１ｍｍの孔７（一部にのみ符号を付す）が４ｍｍ間隔に穿けられている。孔径が小さいと、未硬化樹脂フィルム４を溶融したときの溶融樹脂の流れを阻害する。また、逆に孔径が大きすぎると、未硬化樹脂フィルム５にクラックが生じて細かく砕けた場合に、未硬化樹脂フィルム４の破片の脱落が生じるので、ポリイミドフィルム３，４の孔径および孔数については、十分な配慮が必要である。
【００２２】
樹脂充填体１の具体的な製作手順は下記の通りである。実施例１〜４では、表１の未硬化樹脂成形方法の欄に記してあるように、未硬化樹脂フィルムを粉末プレス成形によって成形した例である。まず、ポリアミック酸の熱イミド化反応によって得られたユーピレックスＡＤのイミドオリゴマー粉末を粉砕・分級して、平均粒径を約３０μｍ以下とした。このようにして得られた粉末を、プレス金型を用いて２００ｍｍ×２００ｍｍのフィルム状に成形した。このようにして成形された未硬化樹脂フィルム５を減圧下でポリイミドフィルム３，４中に真空パックし、ポリイミド融着フィルムを用いてポリイミドフィルム３，４の周囲部を融着して融着部６とし、樹脂充填体１を製作した。ポリイミドフィルム３，４を除いた樹脂フィルム部である未硬化樹脂フィルム５の厚さは、表１に示す通り、０．９４ｍｍ、１．８８ｍｍ、３．７５ｍｍである。
【００２３】
一方、実施例５〜８は、表１の未硬化樹脂成形方法の欄に記してあるように、未硬化樹脂フィルムをイミドオリゴマーの溶融成形によって製作した例である。熱イミド化が終了したユーピレックスＡＤのイミドオリゴマーを３００℃で溶融後これを金型に充填し、わずかに圧力をかけながら金型内で徐冷して、２００ｍｍ×２００ｍｍの平板状フィルムを得た。このようにして得られた未硬化樹脂フィルム５を、減圧下でポリイミドフィルム３，４中に真空パックし、ポリイミド融着フィルムを用いてポリイミドフィルム３，４を融着して樹脂充填体１を製作した。ポリイミドフィルム３，４を除いた未硬化樹脂フィルム５の厚さは、表１に示す通り、０．６８ｍｍ、１．３６ｍｍ、２．７３ｍｍである。いずれも、後述する複合材を製作するために必要なフィルムの面密度から、面密度が同じになるようにフィルム厚さを決定したため、粉末プレス法で成形された実施例１〜４の方が、溶融成形法で成形された実施例５〜８よりも厚くなった。なお、比較例１及び２は、それぞれ粉末プレス成形又は溶融成形によってフィルム化したイミドオリゴマーである。
【００２４】
試作した樹脂充填体１の外観検査結果が表１の最右欄に示されている。まず、比較例１においては、未硬化樹脂フィルムに割れが生じ、樹脂充填体の成形は不可能であった。また、比較例２ではかろうじて未硬化樹脂フィルムが成形できたものの、これをハンドリング中に割れが発生し、ＲＦＩ成形用フィルムに適用することは、全く不適であることがわかった。一方、本発明による実施例においては、厚さが薄い場合には、パックされた未硬化樹脂フィルム５に割れなどは認められず、外観上良好な樹脂充填体１が得られた。しかしながら、実施例１〜４のプレス成形品、実施例５〜８の溶融成形品ともに、未硬化樹脂フィルム５の厚さが厚くなる（フィルム樹脂部分厚さの欄で３．７５ｍｍ又は２．７３ｍｍ）と、成形された未硬化樹脂フィルム５の一部に割れ（クラック）が観察された。樹脂を保持するポリイミドフィルム３，４が１００μｍ（樹脂保持用フィルムのフィルム仕様の欄）と厚い方が未硬化樹脂フィルム５の割れを抑制できる傾向が認められたが、逆に未硬化樹脂フィルム５の柔軟性は低下した。しかしながら、本発明による実施例においては、充填された未硬化樹脂フィルム５中にクラックが発生しても、これをポリイミドフィルム３，４の中にパッキングした樹脂充填体１としての形状保持性には全く問題はなく、ＲＦＩ成形に十分適用可能な形状保持性を有していることがわかった。
【００２５】
表１中の実施例９は、未硬化樹脂フィルム５の形状保持性を向上させた例である。図２は、実施例９に係る樹脂充填体の例を示す模式図である。実施例９に係る樹脂充填体１０は、図２に示すように、溶融成形によって製作された未硬化樹脂フィルム５を２００×２００ｍｍのサイズの区画１２に区画化し、保持体１１を構成するポリイミドフィルム３，４を各区画１２間において融着部６と同様の融着部１３によって融着して、全体として８００ｍｍ×８００ｍｍサイズに作製されている。このように、樹脂充填体１０の寸法が大きくなった場合には、樹脂充填体としての形状保持可能な大きさの複数の区画１２に分割して未硬化樹脂フィルム５をパッキングすることで形状保持性を向上させることにより、サイズ拡大化にも対応可能である。
【００２６】
表１中の実施例１０は、溶融成形によって得られたイミドオリゴマーから成る未硬化樹脂フィルム５をポリイミドフィルム３，４間にパッキングする際に、上下２枚のポリイミドフィルム３，４の端部を融着する代わりに、エポキシ樹脂系接着剤を用いて接着した樹脂充填体を示す。使用した接着剤は２００℃を越えると急激に強度が低下するため、未硬化樹脂フィルム５が溶融する温度（約２９０℃以上）ではポリイミドフィルム３，４の接着端部の接着力が急減し、封止力が低下した端部から溶融した未硬化樹脂を押し出す（又は吸い出し）によって容易に流出させることができる。この方法では、図１に示したような孔７をポリイミドフィルム３に穿ける必要がないという利点がある。
【００２７】
（実施例１１〜１３）
表２に示す実施例１１〜１３は、本発明によって得られたＲＦＩ成形用の樹脂充填体１を用いてＲＦＩ法による複合材平板の製造を行った例である。使用した強化材は、東レ（株）製の高強度炭素繊維Ｔ８００ＨＢ−６Ｋを強化繊維とする５枚朱子織物（織物目付は３１２ｇ／ｍ² ）である。図３は、複合材平板をＲＦＩ成形する際の製造工程を示す模式図である。まず、金型２０の下型２１内に１６０×１６０ｍｍに裁断した炭素繊維織物を所定の枚数（８枚又は１６枚）積層してドライプリフォーム２５とした。この上に、実施例１に示した本発明による樹脂充填体１を、孔７が穿けられたポリイミドフィルム３が下側になるように設置した。織物１枚あたりの目標厚さを０．３ｍｍとし、積層枚数に対応した目標板厚（２．４ｍｍ又は４．８ｍｍ）を設定した。これらの実施例では、計算上の繊維体積率は約５８％である。
【表２】

【００２８】
図４は、実施例１１〜１３における複合材のグラフ化された成形プログラムである。成形工程中、金型２０内はロータリーポンプ２４を用いて常に減圧されている。未硬化樹脂であるユーピレックスＡＤ（分子量１６００バージョン）は、約２８０℃から溶融を開始し、３００℃で炭素繊維織物への含浸には十分な粘度（１０Ｐａ・ｓ）まで低下する。そこで３００℃に達してから徐々に金型２０の加圧（上型２２の加圧）を開始し、下型２１と上型２２との間に形成されるキャビティ２３内において、プリフォーム２５中へのポリイミド樹脂の含浸を行った。最大型締め圧１０ｔｏｎを負荷した状態で、更に温度を３７０℃まで昇温し、１時間保持することによってポリイミド樹脂（未硬化樹脂）を硬化させて複合材を成形した。実施例１１〜１３ともに、ポリイミド樹脂の含浸は良好であり、超音波探傷では欠陥は検出されなかった。また、製造した複合材平板から無孔圧縮試験片を切りだして圧縮強度を測定した結果も良好であった。
【００２９】
しかしながら、実施例１２のように、複合材の板厚が厚くなり、樹脂充填体１の厚さが増すとポリイミド樹脂が流出後の樹脂充填体１にシワが発生し、これが複合材表面に転写されるので、表面の平滑性が損なわれる。板厚が厚い場合には、実施例１３のように、プリフォーム２５の上下両側に樹脂充填体１，１を配置することによって各樹脂充填体１の厚さを薄くし、樹脂流出後の樹脂充填体１に発生するシワを抑制することが効果的である。
【００３０】
実施例１４は、本発明によるＲＦＩ成形用の樹脂充填体１を用いたＲＦＩ成形によって、補強構造を有する平板を一体成形した例である。図５は、本発明における強化繊維複合材料の製造方法によって、実施例１４に示す補強構造を有する平板の製作方法の一例を示す模式図である。実施例１４では、樹脂充填体１が相対的に厚く、また小さいため、孔７穿きフィルムではなく、実施例１０で示した接着剤による封止構造を採用したタイプの樹脂フィルムを用いた。金型３０は、図３に示した金型２０と同様に、下型３１、下型３１と共にキャビティ３３を形成する上型３２、キャビティ３３内のエアを吸引排気して負圧にするロータリーポンプ３４を備えている。上型３２は、プリフォーム３５の補強用の突起部３６を有する形状に合わせて、穴部３７が形成されている。補強構造を有する複合材の成形プログラムは、図４に示すプログラムと同様である。成形された補強平板は、超音波探傷の結果では特に欠陥は認められず、良好な結果が得られた。このように、本発明における樹脂充填体１を用いることによって、複雑な形状の複合材製品であっても容易に製造することが可能である。
【００３１】
（実施例１５）
実施例１５は、保持体を構成する柔軟な多孔質体の開気孔部に複合材のマトリクスとなる樹脂が充填された樹脂充填体の例である。多孔質体としては、多孔質ポリイミド（宇部興産（株）製ユーピレックスフォームＢＦ３０１、密度０．０１ｇ／ｃｍ³ ）を使用した。具体的な製作手順は下記の通りである。まず、ユーピレックスＡＤ（分子量約１６００）を３００℃で加熱溶融し、真空含浸法によって厚さ３ｍｍのユーピレックスフォームの開気孔部に充填させた。ユーピレックスフォームは発泡材ではあるが、壁厚が薄いため、ほとんどが外部に向かって開いた開気孔部となっており、樹脂の充填は良好であった。得られた樹脂充填体は、実施例１〜１０に示した樹脂充填体１と異なり、柔軟性には劣るが、含浸された未硬化樹脂の脱落はほとんどなく、ＲＦＩ成形の樹脂充填体として十分に使用可能であった。多孔質体は形状加工が容易であるため、複雑形状の複合材を製造する際に必要となる複雑形状の樹脂充填体を容易に製作できるという利点がある。図６に示す顕微鏡写真には、複合材のマトリクスとなる樹脂が充填される開気孔部が形成されている樹脂充填体の表面が撮影されている。
【００３２】
【発明の効果】
以上説明したように、本発明の繊維強化複合材料製造用の樹脂充填体によれば、強化繊維又は繊維織物に含浸されたときに複合材のマトリクスとなる未硬化樹脂を保持体内に充填させて成り、保持体は温度上昇によって溶融した未硬化樹脂を外部に流出可能であることから成っているので、従来は脆く強度の弱くフィルム化が不可能である未硬化樹脂に対しても、所定の位置に未硬化樹脂を保持することができ、未硬化樹脂が砕けたり破損すること等に気遣うことなく、取扱が非常に容易になる。また、未硬化樹脂のプリフォームに対する位置や分布も所定の位置や分布に維持することができる。上記の樹脂充填体のサイズが大きくなった場合には、樹脂充填体をいくつかの区画に分割し、かつ各区画間の２枚のフィルムを接着又は融着することにより、樹脂充填体の強度及び柔軟性を向上させることができる。更に、柔軟な多孔質体の開気孔部に複合材のマトリクスとなる樹脂を充填することにより、従来は未硬化樹脂のフィルム化が不可能である樹脂に対しても、また形状が複雑なプリフォームに対してもＲＦＩ法による複合材料の製造を提供することができる。
【００３３】
また、この発明による繊維強化複合材料の製造方法によれば、複合材料の強化繊維又は繊維織物と、保持体に複合材のマトリクスとなる未硬化樹脂を充填し保持した樹脂充填体とを複合材料成形用の型内に設置し、温度を上げることによって保持体に充填した未硬化樹脂を溶融させた後、溶融した樹脂を複合材料の強化繊維又は繊維織物に含浸させることによって複合材料を成形しているので、従来は脆く強度の弱くフィルム化が不可能である未硬化樹脂に対しても、所定の位置に未硬化樹脂を保持することができ、強化繊維や繊維織物のようなプリフォームに対して所定の分布で溶融樹脂を含浸させることができるので、ＲＦＩ法による複合材料を簡単に製造することができる。
【図面の簡単な説明】
【図１】本発明による樹脂充填体の一例（実施例１〜８）を示す模式図である。
【図２】本発明による樹脂充填体の別の例（実施例９）を示す模式図である。
【図３】本発明における実施例１０〜１２において複合材平板をＲＦＩ法によって成形する際の模式図である。
【図４】本発明における強化繊維複合材の製造方法における圧力と温度とで定められる成形プログラムを示した図である。
【図５】本発明における強化繊維複合材料の製造方法による補強平板（実施例１４）を製作する際の模式図である。
【図６】本発明による樹脂充填用の開気孔部を有する樹脂充填体の顕微鏡写真である。
【符号の説明】
１，１０ 樹脂充填体 ２，１１ 保持体
３ ポリイミドフィルム（孔穿き） ４ ポリイミドフィルム
５ 樹脂フィルムの融着部 ６，１３ 溶着部
７ 孔 １２ 区画
２０，３０ ＲＦＩ成形用の金型
２１，３１ 金型の下型 ２２，３２ 金型の上型
２３，３３ キャビティ ２４，３４ ポンプ
２５，３５ プリフォーム（炭素繊維織物）
３６ 突起部 ３７ 穴部[0001]
[Industrial application fields]
The present invention relates to a resin filler used for manufacturing a fiber reinforced composite material by a resin film infusion method (RFI method), and a fiber reinforced composite material manufacturing method using the resin filler.
[0002]
[Prior art]
Conventionally, materials for aerospace are required to have high strength and light weight, but as materials used for these applications, there are advanced composite materials using a thermosetting resin as a matrix. As an advanced composite material manufacturing method, a prepreg in which an uncured resin serving as a matrix is pre-impregnated into a fiber or fiber fabric is manufactured, and this prepreg is laminated on a molding die or inside a mold. The most common is a prepreg molding method that heats and pressurizes. In the prepreg heating / pressurizing step, an autoclave is generally used, but in the case of a simple shape, a hot press or the like is also used.
[0003]
On the other hand, as another manufacturing method of advanced composite materials, a preform of fiber or fiber fabric is installed in a sealed mold, and uncured resin as a matrix is press-fitted into the preform in the mold from the outside. There is an RTM method (resin transfer molding method) in which the resin is cured by impregnating the resin and then heating and pressing. The RTM method is characterized in that a product with good dimensional accuracy and finishing roughness can be manufactured at low cost, and recently, its application has been expanded including aerospace use.
[0004]
As a method similar to the RTM method, a preform made of fiber and woven fabric and an uncured resin film as a matrix are placed in a closed mold, and the whole is heated to melt the resin, and then in the mold There is an RFI method (resin film infusion method) in which a preform is impregnated with a reduced pressure and an external pressure, and further heated to be cured. The RFI method does not require equipment for pumping and injecting resin from the outside like the RTM method, and the preform made of fiber and woven fabric and the uncured resin film serving as the matrix are placed in the mold in an overlapping manner. The amount of resin impregnated into the preform per unit area can be accurately controlled by the film thickness, and, like the RTM method, it is possible to manufacture parts with high dimensional accuracy and good flatness. .
[0005]
However, an important technical problem in the RFI method is to form a film of an uncured resin. The RFI method requires an uncured resin film having flexibility and strength that is not uncured resin but does not break even in handling during production of a composite material or pressure applied during molding. . However, since the uncured resin generally has low strength and is brittle, it is known that even the most common epoxy resin is not easy to produce a film applicable to the RFI method. In particular, in the case of a resin such as a thermosetting polyimide having a small molecular weight in an oligomer state and a glass transition temperature much higher than room temperature, it is practically impossible to produce a film using an uncured resin. It was impossible to apply.
[0006]
[Non-Patent Document 1]
B. Qi et al., “Resin Film Infusion (RFI) Process for Advanced Composite Structure Manufacturing”, Composite Structures, Elsevier Science Ltd., 1999, 47th. Volume, p. 471-476
[0007]
[Problems to be solved by the invention]
Therefore, the uncured resin has almost the same shape and distribution as the uncured resin, which is weak and fragile, and that is easily damaged even when it is made into a film. There is a problem to be solved in that a composite material can be manufactured by making a structure capable of substantially maintaining a predetermined distribution for a preform made of reinforcing fiber or fiber fabric.
[0008]
The object of the present invention is to provide a resin filler that can be used for RFI molding of an uncured resin, which is difficult to form into a film for RFI molding, as compared with the above-described conventional technology, and is obtained as such. Another object of the present invention is to provide a method for producing a reinforced fiber composite material using a resin filler for RFI molding.
[0009]
[Means for Solving the Problems]
In order to solve the above-described problems, a resin filler for producing a fiber-reinforced composite material according to the present invention is an uncured resin that becomes a matrix of a composite material when impregnated in a reinforcing fiber or fiber fabric, and is a resin film-in resin. Fu The holding body is filled with an ineffective resin, which is difficult to form into a film, and the holding body is made of a resin film that can be filled with the uncured resin, and at least a peripheral portion of the resin film is formed. Resin film in, characterized in that it is bonded or fused, and is capable of flowing out the uncured resin melted by temperature rise to the outside Fu It is a resin filler for the production of fiber reinforced composite materials by the fusion method.
[0010]
According to the resin filler for producing the fiber-reinforced composite material, the uncured resin is filled and held in the thermally stable holding body, and the mechanical strength and flexibility are borne by the holding body. Therefore, it does not depend on the strength of the uncured resin that becomes the matrix of the composite material. Since the cured resin is filled and held in the holding body, even if the cured resin is brittle and its strength is low, the relative position with respect to the preform made of the reinforcing fiber or the fiber fabric may be greatly deviated from the predetermined position. Alternatively, the preform can be impregnated with a predetermined amount of a predetermined distribution with a predetermined distribution of the uncured resin melted by the temperature rise. As materials for these holders, fluorinated ethylene resin, polyimide resin, and the like are optimal, but specific materials are not specified.
[0011]
In this resin-filled body for producing a fiber-reinforced composite material, the holding body is composed of the resin film that can be filled with the uncured resin, and at least a peripheral portion of the resin film is bonded or fused. Can do. Since the resin film can have the necessary mechanical strength and flexibility, when the uncured resin is formed into a thin film or film, it is accommodated by sandwiching the uncured resin in between, etc. It is possible to maintain the shape and arrangement. By adhering or fusing at least the periphery of the resin film, for example, a bag-like or shallow tray-like container can be formed, and even an uncured resin with low strength can be sufficiently retained and communicated with the outside. Can be controlled. The resin film can be, for example, an arrangement in which an uncured resin can be accommodated by folding back one film or stacking two films and adhering or fusing the periphery.
[0012]
In this resin-filled body for producing a fiber-reinforced composite material, the holding body is divided into a plurality of sections, and the resin films can be bonded or fused together at a partition portion between the adjacent sections. When the dimension of the resin filler becomes large, it may be difficult to maintain the shape as the resin filler. In such a case, the resin filler is divided into a plurality of sections having a size capable of maintaining the shape, the uncured resin is accommodated in each section, and the resin films between the sections are bonded or fused together. Thus, the strength and flexibility of the resin filler can be improved in correspondence with the enlargement of size. In addition, although the suitable magnitude | size changes with the use purpose, the thickness of a film, the kind of resin, etc., the magnitude | size of a division is not specified for details.
[0013]
In a resin filler for manufacturing a fiber reinforced composite material, in which a holding body is formed from a resin film, at least one hole for allowing the molten uncured resin to flow out is formed in at least one of the resin films. Can do. The resin film filled with the uncured resin needs a route for flowing out the resin melted by heating. For this purpose, for example, when the holding body is formed from two resin films, at least one hole for allowing the molten resin to pass through may be formed in at least one resin film. These holes can be made in advance in the resin film, or can be made immediately before installation in the mold. In the present invention, a specific drilling method for the resin outflow path is not specified.
[0014]
In the resin-filled body for producing a fiber-reinforced composite material in which the holding body is formed from a resin film, the peripheral portion or the partition portion is partially bonded to the outside or to the adjacent section that is not bonded or unfused. You can be in a state. At the end where the resin film of the resin-filled body is fused or bonded, a part of the resin-filled film is unbonded or unfused from the beginning of the production of the resin-filled film, so Can be used as a path for causing the resin melted by heating to flow out.
[0015]
In the resin filler for manufacturing a fiber reinforced composite material in which the holding body is formed from a resin film, the peripheral portion or the partition portion is formed by adhesion of the resin film, and the strength of the adhesion is the peripheral portion or the Part or all of the partition portion can be set to a strength that decreases in the melting temperature range of the resin. As another method of causing the molten resin to flow out, in the temperature range where the filled resin melts, the adhesive strength of part or all of the bonded end portions of the upper and lower two films filled with the resin is reduced. Thus, the adhesive end of the film can be intentionally peeled off in the necessary temperature range to allow the resin to flow out.
[0016]
In the resin filler for producing the fiber-reinforced composite material, the uncured resin can be an uncured imide oligomer formed into a film by powder press molding or melt molding. Polyimide that is difficult to mold can also be melted by heating and impregnated into a preform by filling and holding the resin film.
[0017]
Further, in the resin-filled body for producing the fiber-reinforced composite material, the holding body is a flexible porous body having a large number of open pores, and the open pores when the uncured resin is melted by a temperature rise. The open pores are filled so that they can flow out from the outside. Place the resin filler in which the open pores of the flexible porous body are filled with the uncured resin that is the matrix of the composite material together with the reinforcing fiber or fiber fabric of the composite material in the mold for molding the composite material, When the resin filled in the open pores is melted by raising, it is possible to impregnate the reinforced fiber or fiber fabric of the composite material with the molten resin for molding the composite material. The uncured resin is filled in the open pores of the thermally stable porous body, and the mechanical strength and flexibility are borne by these porous bodies, so that it does not depend on the strength of the uncured resin. Since the porous body can be easily processed, it is easy to manufacture a resin-filled body having a complicated shape that is necessary when manufacturing a complex-shaped composite material. For these holding films, fluorinated ethylene resin, polyimide resin, silicone resin, and the like are optimal, but specific materials are not specified.
[0018]
The method for producing a fiber-reinforced composite material according to the present invention is a resin film-in method. Fu A fiber reinforced composite material manufacturing method by a fusion method, wherein the reinforcing fiber or fiber fabric and the resin filler according to any one of claims 1 to 7 are placed in a mold for molding a composite material, and the temperature The uncured resin filled in the resin filling body is melted by raising and the molten uncured resin is impregnated into the reinforcing fiber or the fiber fabric by pressurization.
[0019]
According to this method for producing a reinforced fiber composite material, a reinforced fiber or fiber fabric of the composite material and a resin filler filled with an uncured resin serving as a matrix of the composite material are placed in a mold for molding the composite material. The composite material can be formed by melting the uncured resin filled in the resin filler by increasing the temperature and impregnating the molten resin into the reinforcing fiber of the composite material. At least a part of the resin film constituting the resin filler is made to have at least one hole in advance in order to allow the molten uncured resin to flow out, or it is put into a mold for molding a composite material. It can be drilled immediately prior to loading and placed in a mold for molding a composite material with reinforcing fibers or fiber fabrics.
[0020]
【Example】
Examples of the present invention will be specifically described below.
(Examples 1-9)
Examples of the present invention are shown in Table 1 and FIG. FIG. 1 is a schematic view showing an example of a resin filler. As shown in FIG. 1, the resin filler 1 shown in Examples 1 to 8 is composed of two polyimide films 3 and 4 (made by Ube Industries, Upilex) as resin films forming the holding body 2 according to the present invention. S, having a thickness of 25 μm or 100 μm), an uncured imide oligomer film (hereinafter referred to as “uncured resin film”) 5 as an uncured resin according to the present invention is packed. The uncured resin film 5 is made by molding thermosetting polyimide (manufactured by Ube Industries, Upilex AD, average molecular weight MW to 1600 g / mole).
[Table 1]

[0021]
The uncured resin film 5 is filled between two polyimide films 3 and 4 and then fused around the polyimide films 3 and 4 with a fused film to form a fused portion 6. The inside filled with the film 5 is sealed. Here, one polyimide film 3 is provided with holes 7 having a diameter of φ1 mm (a part of which is given a reference numeral) at intervals of 4 mm. When the pore diameter is small, the flow of the molten resin when the uncured resin film 4 is melted is hindered. On the other hand, if the hole diameter is too large, cracks occur in the uncured resin film 5 and the fragments of the uncured resin film 4 fall off when the uncured resin film 5 is broken finely. Should be considered carefully.
[0022]
The specific manufacturing procedure of the resin filler 1 is as follows. In Examples 1 to 4, as described in the column of the uncured resin molding method in Table 1, an uncured resin film was molded by powder press molding. First, the imide oligomer powder of Upilex AD obtained by the thermal imidization reaction of polyamic acid was pulverized and classified so that the average particle size was about 30 μm or less. The powder thus obtained was molded into a 200 mm × 200 mm film using a press die. The uncured resin film 5 thus molded is vacuum-packed in the polyimide films 3 and 4 under reduced pressure, and the peripheral portions of the polyimide films 3 and 4 are fused using a polyimide fused film to be fused. 6 and the resin filler 1 was manufactured. As shown in Table 1, the thickness of the uncured resin film 5 that is a resin film portion excluding the polyimide films 3 and 4 is 0.94 mm, 1.88 mm, and 3.75 mm.
[0023]
On the other hand, Examples 5-8 are the examples which manufactured the uncured resin film by melt molding of the imide oligomer as described in the column of the uncured resin molding method of Table 1. The imide oligomer of Upilex AD, which had been subjected to thermal imidization, was melted at 300 ° C. and then filled in a mold, and slowly cooled in the mold while applying a slight pressure to obtain a flat film of 200 mm × 200 mm. . The uncured resin film 5 thus obtained is vacuum-packed in the polyimide films 3 and 4 under reduced pressure, and the polyimide films 3 and 4 are fused using the polyimide fusion film to obtain the resin filler 1. Produced. As shown in Table 1, the thickness of the uncured resin film 5 excluding the polyimide films 3 and 4 is 0.68 mm, 1.36 mm, and 2.73 mm. In any case, since the film thickness was determined so that the surface density was the same from the surface density of the film necessary for producing the composite material described later, the Examples 1 to 4 formed by the powder press method were more preferable. It became thicker than Examples 5-8 molded by the melt molding method. Comparative Examples 1 and 2 are imide oligomers formed into films by powder press molding or melt molding, respectively.
[0024]
The appearance inspection results of the prototype resin filler 1 are shown in the rightmost column of Table 1. First, in Comparative Example 1, the uncured resin film was cracked, and it was impossible to mold the resin filler. Moreover, although the uncured resin film was barely able to be molded in Comparative Example 2, it was found that cracking occurred during handling, and it was completely unsuitable to apply it to the RFI molding film. On the other hand, in the Example by this invention, when the thickness was thin, the packed uncured resin film 5 was not found to be cracked, and the resin filler 1 having a good appearance was obtained. However, the thickness of the uncured resin film 5 increases in both the press-molded products of Examples 1 to 4 and the melt-molded products of Examples 5 to 8 (3.75 mm or 2.73 mm in the column of film resin partial thickness). ) And cracks were observed in a part of the molded uncured resin film 5. Although the polyimide film 3 and 4 which hold | maintain resin have the tendency which can suppress the crack of the uncured resin film 5 as the thicker one is 100 micrometers (column of the film specification of the film for resin retention), conversely, the uncured resin film 5 The flexibility decreased. However, in the embodiment according to the present invention, even if a crack occurs in the filled uncured resin film 5, the shape retaining property as the resin filler 1 in which this is packed in the polyimide films 3 and 4 is not sufficient. There was no problem at all, and it was found that the film has shape retention sufficient for RFI molding.
[0025]
Example 9 in Table 1 is an example in which the shape retention of the uncured resin film 5 is improved. FIG. 2 is a schematic diagram illustrating an example of a resin filler according to Example 9. As shown in FIG. 2, the resin filler 10 according to Example 9 is a polyimide film that forms a holder 11 by partitioning an uncured resin film 5 manufactured by melt molding into sections 12 having a size of 200 × 200 mm. 3 and 4 are fused between the respective sections 12 by the fused portion 13 similar to the fused portion 6, and are manufactured to a size of 800 mm × 800 mm as a whole. As described above, when the size of the resin filler 10 is increased, the shape is maintained by packing the uncured resin film 5 into a plurality of sections 12 having a size capable of retaining the shape as the resin filler. By improving the performance, it is possible to cope with an increase in size.
[0026]
In Example 10 in Table 1, when the uncured resin film 5 made of imide oligomer obtained by melt molding is packed between the polyimide films 3 and 4, the ends of the upper and lower polyimide films 3 and 4 are A resin filler bonded using an epoxy resin adhesive instead of fusing is shown. Since the strength of the adhesive used decreases rapidly when it exceeds 200 ° C., the adhesive strength of the bonded end portions of the polyimide films 3 and 4 rapidly decreases at the temperature at which the uncured resin film 5 melts (about 290 ° C. or more). The melted uncured resin can be easily drained (or sucked out) from the end where the sealing force is reduced. This method has an advantage that the hole 7 as shown in FIG.
[0027]
(Examples 11 to 13)
Examples 11 to 13 shown in Table 2 are examples in which composite flat plates were produced by the RFI method using the RFI molding resin filler 1 obtained according to the present invention. The reinforcing material used was a five-sheet satin woven fabric with a high-strength carbon fiber T800HB-6K manufactured by Toray Industries, Inc. (the fabric weight is 312 g / m) ² ). FIG. 3 is a schematic diagram showing a manufacturing process when RFI molding is performed on a composite material flat plate. First, a predetermined number (8 or 16) of carbon fiber fabrics cut into 160 × 160 mm in the lower mold 21 of the mold 20 was laminated to obtain a dry preform 25. On top of this, the resin filler 1 according to the present invention shown in Example 1 was placed so that the polyimide film 3 with the holes 7 formed on the lower side. The target thickness per fabric was set to 0.3 mm, and a target plate thickness (2.4 mm or 4.8 mm) corresponding to the number of laminated sheets was set. In these examples, the calculated fiber volume fraction is about 58%.
[Table 2]

[0028]
FIG. 4 is a graphed forming program of the composite material in Examples 11-13. During the molding process, the inside of the mold 20 is constantly decompressed using the rotary pump 24. Upilex AD (molecular weight 1600 version), which is an uncured resin, starts to melt from about 280 ° C. and decreases to a viscosity (10 Pa · s) sufficient for impregnation into a carbon fiber fabric at 300 ° C. Therefore, after reaching 300 ° C., pressurization of the mold 20 (pressurization of the upper mold 22) is started gradually, and in the cavity 25 formed between the lower mold 21 and the upper mold 22, The polyimide resin was impregnated. With the maximum mold clamping pressure of 10 tons, the temperature was further raised to 370 ° C. and held for 1 hour to cure the polyimide resin (uncured resin) and form a composite material. In each of Examples 11 to 13, the polyimide resin was satisfactorily impregnated, and no defects were detected by ultrasonic flaw detection. Moreover, the result of cutting out a non-porous compression test piece from the produced composite material flat plate and measuring the compression strength was also good.
[0029]
However, as in Example 12, when the thickness of the composite material increases and the thickness of the resin filler 1 increases, wrinkles occur in the resin filler 1 after the polyimide resin flows out, and this is transferred to the surface of the composite material. Therefore, the smoothness of the surface is impaired. When the plate is thick, the resin fillers 1 and 1 are arranged on both the upper and lower sides of the preform 25 to reduce the thickness of each resin filler 1 as in Example 13, and the resin after the resin flows out. It is effective to suppress wrinkles generated in the filler 1.
[0030]
Example 14 is an example in which a flat plate having a reinforcing structure is integrally molded by RFI molding using the RFI molding resin filler 1 according to the present invention. FIG. 5 is a schematic view showing an example of a method for producing a flat plate having a reinforcing structure shown in Example 14 by the method for producing a reinforcing fiber composite material according to the present invention. In Example 14, since the resin filler 1 was relatively thick and small, a resin film of the type employing the sealing structure with the adhesive shown in Example 10 was used instead of the film having 7 holes. As with the mold 20 shown in FIG. 3, the mold 30 includes a lower mold 31, an upper mold 32 that forms a cavity 33 together with the lower mold 31, and a rotary pump that sucks and exhausts the air in the cavity 33 to make negative pressure. 34 is provided. The upper mold 32 is formed with a hole 37 according to the shape of the preform 35 having the reinforcing protrusion 36. The composite material molding program having the reinforcing structure is the same as the program shown in FIG. The molded reinforcing plate did not show any particular defect as a result of ultrasonic flaw detection, and good results were obtained. As described above, by using the resin filler 1 in the present invention, it is possible to easily manufacture even a complex-shaped composite material product.
[0031]
(Example 15)
Example 15 is an example of a resin-filled body in which a resin serving as a matrix of a composite material is filled in an open pore portion of a flexible porous body that constitutes a holding body. As the porous material, porous polyimide (Upilex foam BF301 manufactured by Ube Industries, Ltd., density 0.01 g / cm) ^Three )It was used. The specific manufacturing procedure is as follows. First, Upilex AD (molecular weight of about 1600) was heated and melted at 300 ° C., and filled into the open pores of Upilex foam having a thickness of 3 mm by vacuum impregnation. Upilex foam is a foam material, but since the wall thickness is thin, most of the open pores are open pores that open to the outside, and the resin filling is good. Unlike the resin filler 1 shown in Examples 1 to 10, the obtained resin filler is inferior in flexibility, but the impregnated uncured resin hardly falls off and is sufficient as a resin filler for RFI molding. It was possible to use it. Since the porous body is easy to shape, there is an advantage that it is possible to easily manufacture a resin filler having a complicated shape that is necessary when manufacturing a complex composite material. In the micrograph shown in FIG. 6, the surface of the resin-filled body in which the open pores filled with the resin serving as the matrix of the composite material are formed is photographed.
[0032]
【The invention's effect】
As described above, according to the resin filler for producing a fiber-reinforced composite material of the present invention, the holding body is filled with an uncured resin that becomes a matrix of the composite material when impregnated in a reinforcing fiber or fiber fabric. The holding body consists of being able to flow out the uncured resin melted by the temperature rise to the outside. The uncured resin can be held at the position, and the handling becomes very easy without worrying about the uncured resin being crushed or damaged. Further, the position and distribution of the uncured resin with respect to the preform can be maintained at a predetermined position and distribution. When the size of the resin filler is increased, the resin filler is divided into several sections, and the two films between the sections are bonded or fused, whereby the strength of the resin filler is increased. In addition, flexibility can be improved. Furthermore, by filling the open pores of a flexible porous body with a resin that is a matrix of a composite material, a resin with a complicated shape can be used even for resins that could not be made into a film of an uncured resin. The production of composite materials by the RFI method can also be provided for reform.
[0033]
Further, according to the method for producing a fiber-reinforced composite material according to the present invention, the composite material includes a reinforced fiber or a fiber fabric of the composite material, and a resin filling body in which the holding body is filled with an uncured resin serving as a matrix of the composite material and held. After the uncured resin filled in the holding body is melted by placing it in a mold for molding and raising the temperature, the composite material is molded by impregnating the molten resin into the reinforcing fiber or fiber fabric of the composite material. Therefore, it is possible to hold the uncured resin at a predetermined position even for uncured resin that is brittle and weak in strength and cannot be formed into a film. On the other hand, since the molten resin can be impregnated with a predetermined distribution, a composite material by the RFI method can be easily manufactured.
[Brief description of the drawings]
FIG. 1 is a schematic view showing an example (Examples 1 to 8) of a resin filler according to the present invention.
FIG. 2 is a schematic view showing another example (Example 9) of the resin filler according to the present invention.
FIG. 3 is a schematic view when a composite flat plate is formed by RFI method in Examples 10 to 12 of the present invention.
FIG. 4 is a diagram showing a molding program determined by pressure and temperature in the method for producing a reinforcing fiber composite material according to the present invention.
FIG. 5 is a schematic view when a reinforcing flat plate (Example 14) is manufactured by the method for manufacturing a reinforcing fiber composite material according to the present invention.
FIG. 6 is a photomicrograph of a resin filler having open pores for resin filling according to the present invention.
[Explanation of symbols]
1,10 Resin filler 2,11 Holder
3 Polyimide film (drilled) 4 Polyimide film
５ Resin film fusion part 6,13 Weld part
7 holes 12 sections
20, 30 Mold for RFI molding
21 and 31 Lower mold 22 and 32 Upper mold
23,33 Cavity 24,34 Pump
25, 35 preform (carbon fiber fabric)
36 Projection 37 Hole

Claims (8)

The holding body is filled with an uncured resin that becomes a matrix of a composite material when impregnated in a reinforcing fiber or fiber fabric, and the holding body is made of a resin film that can be filled with the uncured resin in between. at least the periphery portion consists are bonded or fused, and the temperature resin film in Der characterized in that it consists of said melted is possible outflow of uncured resin to the outside by the rise of the resin film Resin filler for the production of fiber reinforced composite materials by the fusion method. 2. The fiber-reinforced composite material production according to claim 1 , wherein the holding body is divided into a plurality of sections, and the resin films are bonded or fused together at a partition between the adjacent sections. Resin filler. The resin for producing a fiber-reinforced composite material according to claim 1 or 2 , wherein at least one hole for allowing the melted uncured resin to flow out is formed in at least a part of the resin film. Filling body. The fiber according to any one of claims 1 to 3 , wherein a part of the peripheral part or the partition part is in an unbonded or unfused state in which a part thereof can communicate with the outside or the adjacent section. Resin filler for manufacturing reinforced composite materials. The peripheral part or the partition part is formed by adhesion of the resin film, and the strength of the adhesion is such that a part or all of the peripheral part or the partition part decreases in the melting temperature range of the resin. The resin filler for producing a fiber-reinforced composite material according to claim 1 , which is set.   The resin filler for producing a fiber-reinforced composite material according to claim 1, wherein the uncured resin is an uncured imide oligomer formed into a film by powder press molding or melt molding.   The holding body is a flexible porous body having a large number of open pores, and the uncured resin is filled in the open pores so that the uncured resin can flow out from the open pores when melted due to a temperature rise. A resin filler for producing a fiber-reinforced composite material according to claim 1. The reinforcing fiber or the fiber fabric, and the resin filler according to any one of claims 1 to 7 are placed in a mold for molding a composite material, and the resin filler is filled by raising the temperature. the uncured resin is melted, the production of molten the fiber-reinforced composite material according to resin film Inn Der, Version method characterized by consisting in impregnating the reinforcing fibers or the fiber fabric uncured resin by pressure Method.

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