JP2016179647A - Method for producing fiber-reinforced plastic - Google Patents
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本発明は、繊維強化プラスチックを加圧成形するに際し、良好な流動性、三次元形状に賦形する際に優れた形状追従性を担保し、良好な表面品位、優れた寸法安定性を発現する繊維強化プラスチックの製造方法に関する。 The present invention ensures good fluidity and excellent shape followability when forming into a three-dimensional shape when pressure-molding fiber reinforced plastic, and exhibits good surface quality and excellent dimensional stability. The present invention relates to a method for producing fiber-reinforced plastic.
強化繊維とマトリックス樹脂からなる繊維強化プラスチックは、比強度、比弾性率に優れ、航空機構造部材、自動車構造部材をはじめとした輸送機器分野のみならず、圧力容器部材、ゴルフシャフトといった一般産業分野への適用が拡大し、その需要は年々増加しつつある。 Fiber reinforced plastic made of reinforced fiber and matrix resin is excellent in specific strength and specific elastic modulus, and not only in the field of transportation equipment such as aircraft structural members and automobile structural members, but also in general industrial fields such as pressure vessel members and golf shafts. The application is expanding and the demand is increasing year by year.
これらの構造部材には、繊維強化プラスチックの中でも特に力学特性に優れた、プリプレグと称される連続した強化繊維にマトリックス樹脂を含浸せしめた半硬化状態の中間基材を用いることが多い。中でも、繊維が一方向に引き揃えられた一方向プリプレグは、繊維体積含有率が向上し、強化繊維の高い弾性率、強度を最大限に活用できるとともに、高機能性を有するマトリックス樹脂をあらかじめ目付けばらつき少なく含浸させておくことで、材料品質が安定する。 These structural members often use a semi-cured intermediate base material in which continuous reinforcing fibers called prepregs are impregnated with a matrix resin, which are particularly excellent in mechanical properties among fiber reinforced plastics. Above all, the unidirectional prepreg with the fibers aligned in one direction improves the fiber volume content, maximizes the high elastic modulus and strength of the reinforced fiber, and pre-loads a highly functional matrix resin. The material quality is stabilized by impregnating with less variation.
プリプレグを用いた繊維強化プラスチックの成形方法として、プリプレグを積層し、高温高圧釜で加圧加熱することによりマトリックス樹脂を硬化させて繊維強化プラスチックを成形するオートクレーブ成形が最も一般的である。また、プリプレグの積層体を予備加熱して、軟化状態にある該積層体を雌雄一対の両面型に供給し、次いで加圧することで所望の形状の成形体を得る、プレス成形も広く行われている。特に、プレス成形は、比較的均一な精度の製品を大量生産可能である特徴があり、大量生産を行うために高速化、高精度化、品質の安定化などの要求が高く、それらを実現するために、成形性の向上に関する市場からの要求は高い。 The most common method for molding fiber reinforced plastics using prepregs is autoclave molding in which prepregs are laminated and heated in a high temperature and high pressure kettle to cure the matrix resin and mold the fiber reinforced plastics. In addition, press molding is widely performed in which a prepreg laminate is preheated, the laminate in a softened state is supplied to a pair of male and female double-sided molds, and then pressed to obtain a molded body having a desired shape. Yes. In particular, press molding is characterized by the ability to mass-produce products with relatively uniform accuracy, and there is a high demand for high-speed, high-precision, and stable quality for mass production. Therefore, there is a high demand from the market regarding improvement of formability.
これらの成形方法により得られた繊維強化プラスチックは、連続繊維で構成されるため、優れた力学特性を発現する。また、連続繊維は規則的な配列であるため、積層構成の設計により、要求される力学特性、さらされる荷重状態を考慮した設計が可能で、設計の自由度が高く、力学特性のばらつきも小さい。しかしながら一方で、高い弾性率を有する強化繊維自体の伸縮性は乏しく、凹凸部やコーナー部など複雑な三次元形状を形成することは困難である。このような連続繊維を有するプリプレグを賦形した場合、表面形状を覆いきれない箇所で強化繊維の突っ張りが、また、プリプレグが余った箇所で強化繊維が座屈して皺が発生するため、高品位な賦形が難しい。連続繊維を有するプリプレグであっても、織物にマトリックス樹脂を含浸させた基材であれば、面内せん断変形が可能となり、賦形は容易となるが、複雑形状であれば、繊維の突っ張りや皺が発生してしまう問題があった。 Since the fiber reinforced plastic obtained by these molding methods is composed of continuous fibers, it exhibits excellent mechanical properties. In addition, since the continuous fibers are regularly arranged, it is possible to design by considering the required mechanical properties and exposed load conditions by designing the laminated structure, and the degree of freedom in design is high and the variation in mechanical properties is small. . However, on the other hand, the stretchability of the reinforcing fiber itself having a high elastic modulus is poor, and it is difficult to form a complicated three-dimensional shape such as an uneven portion or a corner portion. When a prepreg having such continuous fibers is shaped, the reinforcing fibers are stretched at places where the surface shape cannot be covered, and the reinforcing fibers buckle at the places where the prepregs are left, resulting in wrinkles. Is difficult to form. Even a prepreg having continuous fibers can be subjected to in-plane shear deformation if it is a base material in which a woven fabric is impregnated with a matrix resin, and shaping is easy. There was a problem that wrinkles occurred.
一方、凹凸部等の三次元形状の部材成形に適した成形方法として、ＳＭＣ（シートモールディングコンパウンド）を用いたプレス成形がある。この成形法では、通常２５ｍｍ程度に切断したチョップドストランドに熱硬化性のマトリックス樹脂を含浸せしめ半硬化状態としたＳＭＣシートを、プレス機を用いて加熱・加圧することにより成形を行う。一般的に、加圧前にＳＭＣを成形体の形状より小さく切断して成形型内に配置し、加圧により成形体の形状に流動させて成形を行う。そのため、流動により凹凸部や複合曲面等の複雑形状にも追従可能となる。しかしながら、ＳＭＣはそのシート加工の工程において、チョップドストランドの分布ムラ、配向ムラが必然的に生じてしまうため、力学特性が低下することに加えて、力学特性自体のばらつきが大きくなる問題があった。さらに、特に薄物の部材ではソリ、ヒケ等が発生しやすく、主要構造部材への適用は困難である場合が多い。 On the other hand, as a molding method suitable for molding a three-dimensional member such as a concavo-convex portion, there is press molding using SMC (sheet molding compound). In this molding method, the SMC sheet which is made into a semi-cured state by impregnating a chopped strand, which is usually cut to about 25 mm, with a thermosetting matrix resin, is heated and pressed using a press. In general, before pressurization, the SMC is cut smaller than the shape of the molded body, placed in a mold, and molded into the shape of the molded body by pressurization. Therefore, it becomes possible to follow complicated shapes such as uneven portions and composite curved surfaces by flow. However, SMC has a problem that uneven distribution of the chopped strands and uneven alignment of the chopped strands are inevitably generated in the sheet processing process, so that in addition to the deterioration of the mechanical characteristics, the dispersion of the mechanical characteristics itself becomes large. . Furthermore, warping, sink marks, etc. are likely to occur especially in thin members, and application to main structural members is often difficult.
特許文献１では、生産性に優れる成形プロセスとして、平板状に積層したプリプレグ積層体を一気に三次元形状に賦形するホットフォーミング法が開示されている。しかしながら、賦形時にプリプレグの形状追従性不足に起因する皺や繊維の突っ張りが発生し、繊維強化プラスチックの品位が低下する問題があった。プリプレグ積層体が硬化され繊維強化プラスチックとなる過程で厚みが減少するため、形状変化の大きい部位、例えばコーナー部に賦形されたプリプレグ積層体は硬化に伴い、強化繊維が座屈して皺になるか、繊維突っ張りを起こして型形状に追従しない、という成形不具合が起こる。また、突っ張りが生じた強化繊維直下では成形圧が加わり難いことから、ボイドが発生しやすい問題があった。 Patent Document 1 discloses a hot forming method in which a prepreg laminate laminated in a flat plate shape is formed into a three-dimensional shape at a stretch as a molding process with excellent productivity. However, there is a problem that wrinkles and fiber stretching occur due to insufficient shape following ability of the prepreg during shaping, and the quality of the fiber reinforced plastic is lowered. As the thickness of the prepreg laminate is reduced to a fiber reinforced plastic, the thickness of the prepreg laminate is reduced. For this reason, the prepreg laminate formed at the part having a large shape change, for example, the corner portion, buckles and becomes wrinkled as the reinforced fiber is cured. Or, there is a molding defect that the fiber is stretched and does not follow the mold shape. In addition, there is a problem that voids are easily generated because it is difficult to apply a molding pressure directly under the reinforcing fiber where the tension is generated.
特許文献２には、プリプレグ積層体に含まれる樹脂が最低粘度となる温度に加温して軟化させた状態で賦形し、その後硬化温度まで昇温する技術が開示されている。しかしながら、実際には樹脂の粘度が低下しすぎて、加圧したプリプレグ積層体から樹脂が絞り出される一方、強化繊維はほとんど流動しないという問題があった。またこの樹脂絞り出しは、成形品の繊維体積含有率Ｖｆの制御を困難とし、力学特性のばらつきに加えて、表面に樹脂不足が生じ表面品位を悪化させる。 Patent Document 2 discloses a technique in which a resin contained in a prepreg laminate is shaped to a temperature at which the resin is heated to a minimum viscosity and softened, and then heated to a curing temperature. However, in reality, the viscosity of the resin is too low and the resin is squeezed out from the pressurized prepreg laminate, while the reinforcing fibers hardly flow. In addition, this resin squeezing makes it difficult to control the fiber volume content Vf of the molded product, and in addition to variations in mechanical properties, the surface lacks resin and deteriorates the surface quality.
本発明の課題は、かかる背景技術を鑑み、シート上の中間基材を加圧成形により、三次元形状に賦形、成形するにあたり、サイクルタイムが短く、良好な流動性、優れた形状追従性を担保し、繊維強化プラスチックを加圧成形した場合、良好な表面品位、優れた寸法安定性を発現する繊維強化プラスチックの製造方法を提供することにある。 In view of the background art, the object of the present invention is to form an intermediate base material on a sheet into a three-dimensional shape by pressure molding, with a short cycle time, good fluidity, and excellent shape followability. It is an object of the present invention to provide a method for producing a fiber reinforced plastic that exhibits good surface quality and excellent dimensional stability when the fiber reinforced plastic is pressure-molded.
本発明の繊維強化プラスチックの製造方法は、上記した課題を解決するため、次のような手段を採用するものである。強化繊維に熱硬化性樹脂を含浸させてなるプリプレグを積層したプリプレグ積層体を、その少なくとも片面を型に接して加圧し、加熱により硬化させて成形する繊維強化プラスチックの製造方法であって、プリプレグと型との間の摩擦係数が、プリプレグとプリプレグの間の摩擦係数よりも低くなる温度であって、プリプレグと型との間の摩擦係数が最小となる温度±１０℃の範囲内に加温したプリプレグ積層体を加圧した後、所定の温度まで昇温し、温度を保持して硬化させる繊維強化プラスチックの製造方法である。 The manufacturing method of the fiber reinforced plastic of the present invention employs the following means in order to solve the above-described problems. A method for producing a fiber reinforced plastic comprising forming a prepreg laminate in which a prepreg obtained by impregnating a reinforced fiber with a thermosetting resin is laminated, pressing at least one surface of the prepreg in contact with a mold, and curing by heating. The temperature of the friction coefficient between the prepreg and the mold is lower than the friction coefficient between the prepreg and the mold, and the temperature is within a range of ± 10 ° C. at which the friction coefficient between the prepreg and the mold is minimized. This is a method for producing a fiber reinforced plastic, in which the prepreg laminate is pressurized, heated to a predetermined temperature, and cured while maintaining the temperature.
本発明によれば、平板状のプリプレグ積層体を三次元形状への形状追従性に優れ、良好な表面品位、優れた寸法安定性を発現する繊維強化プラスチックを、短いサイクルタイムで製造することができる。 According to the present invention, it is possible to produce a fiber reinforced plastic that has a flat prepreg laminate with excellent shape following to a three-dimensional shape, good surface quality, and excellent dimensional stability in a short cycle time. it can.
以下、本発明を詳細に説明する。 Hereinafter, the present invention will be described in detail.
本発明では、強化繊維に熱硬化性樹脂を含浸させてなるプリプレグを基材として使用する。プリプレグの繊維体積含有率Ｖｆは４５〜６５％の範囲内であることが好ましい。Ｖｆが６５％以下で十分な流動性を得ることができ、低いほど流動性が向上するが、Ｖｆが４５％より小さくなると、構造材に必要な力学特性が得られない場合がある。流動性と力学特性との関係を鑑みると、さらに好ましくはＶｆが５５〜６０％の範囲内である。 In the present invention, a prepreg obtained by impregnating a reinforcing fiber with a thermosetting resin is used as a base material. The fiber volume content Vf of the prepreg is preferably in the range of 45 to 65%. Sufficient fluidity can be obtained with a Vf of 65% or less, and the lower the Vf, the better the fluidity. However, if Vf is less than 45%, the mechanical properties required for the structural material may not be obtained. In view of the relationship between fluidity and mechanical properties, Vf is more preferably in the range of 55 to 60%.
プリプレグを構成する強化繊維としては、炭素繊維、アラミド繊維、ガラス繊維などの脆性繊維のほか、金属繊維、合成繊維などの延性繊維が挙げられる。その中でも特に炭素繊維はこれら強化繊維の中でも軽量であり、比強度および比弾性率において特に優れた性質を有しており、加えて耐熱性や耐薬品性にも優れることから、構造部材に好適である。なかでも、高強度の炭素繊維が得られやすいＰＡＮ（ポリアクリロニトリル）系炭素繊維が好ましい。 Examples of reinforcing fibers constituting the prepreg include brittle fibers such as carbon fibers, aramid fibers, and glass fibers, and ductile fibers such as metal fibers and synthetic fibers. Among them, carbon fiber is particularly lightweight among these reinforcing fibers, and has particularly excellent properties in specific strength and specific elastic modulus. In addition, it has excellent heat resistance and chemical resistance, so it is suitable for structural members. It is. Of these, PAN (polyacrylonitrile) -based carbon fibers from which high-strength carbon fibers can be easily obtained are preferred.
また、プリプレグを構成する熱硬化性樹脂はマトリックス樹脂として用いられる。熱硬化性樹脂としては、エポキシ樹脂、ビニルエステル樹脂、フェノール樹脂、不飽和ポリエステル樹脂等が挙げられ、樹脂が熱により架橋反応を起こし、少なくとも部分的な三次元架橋構造を形成するものであればよい。プリプレグにおける熱硬化性樹脂の形態としては、プリプレグ積層時にプリプレグ同士を圧着する必要があることから、タック性に優れる半硬化状態であることが好ましい。中でも、貼り付ける工程でのタック性、および繊維強化プラスチックとしたときの力学特性を考慮するとエポキシ樹脂が好ましい。 Moreover, the thermosetting resin which comprises a prepreg is used as a matrix resin. Examples of thermosetting resins include epoxy resins, vinyl ester resins, phenol resins, unsaturated polyester resins, etc., as long as the resin undergoes a crosslinking reaction by heat and forms at least a partial three-dimensional crosslinked structure. Good. The form of the thermosetting resin in the prepreg is preferably a semi-cured state having excellent tackiness because it is necessary to press-bond the prepregs together during prepreg lamination. Among these, an epoxy resin is preferable in consideration of tackiness in the attaching process and mechanical characteristics when a fiber reinforced plastic is used.
本発明では、プリプレグを積層したプリプレグ積層体を、その少なくとも片面を型に接して加圧し、加熱によりマトリックス樹脂を硬化させて繊維強化プラスチックを成形する。その際、プリプレグ積層体を構成する表面のプリプレグと型との間の摩擦係数、すなわちプリプレグと型面との摩擦係数が、プリプレグ積層体を構成するプリプレグとプリプレグの間の摩擦係数、すなわちプリプレグ同士の摩擦係数よりも低くなる温度であって、プリプレグと型との間の摩擦係数が最小となる温度±１０℃の範囲内に、プリプレグ積層体を加温して加圧する。そして、その後に所定の温度まで昇温し、温度を保持して、マトリックス樹脂を硬化させる。プリプレグ同士の摩擦係数が、プリプレグと型面との摩擦係数よりも、低い温度領域で、加圧した場合、プリプレグ積層体の最表層のプリプレグを除いたプリプレグ層が優先的に流動して、最表層のプリプレグの追従が遅れ、得られる繊維強化プラスチックの表面品位が悪化してしまう問題がある。またプリプレグと型面との摩擦係数が、プリプレグ同士の摩擦係数よりも低い温度域であっても、プリプレグと型面との摩擦係数が大きければ、流動は限定的であるため、プリプレグと型面との摩擦係数が最小となる温度±１０℃の範囲内で加圧されることで、最も良好な表面品位を発現する繊維強化プラスチックを得ることができる。 In the present invention, a prepreg laminate in which prepregs are laminated is pressed while at least one surface thereof is in contact with a mold, and the matrix resin is cured by heating to form a fiber reinforced plastic. At that time, the friction coefficient between the prepreg on the surface constituting the prepreg laminate and the mold, that is, the friction coefficient between the prepreg and the mold surface is the friction coefficient between the prepreg and prepreg constituting the prepreg laminate, that is, between the prepregs. The prepreg laminate is heated and pressed within a temperature range of ± 10 ° C. at which the friction coefficient between the prepreg and the mold is minimized. Then, the temperature is raised to a predetermined temperature, and the matrix resin is cured while maintaining the temperature. When pressure is applied in a temperature range where the friction coefficient between prepregs is lower than the friction coefficient between the prepreg and the mold surface, the prepreg layer excluding the prepreg on the outermost layer of the prepreg laminate preferentially flows, and the There is a problem that the follow-up of the prepreg on the surface layer is delayed, and the surface quality of the fiber-reinforced plastic obtained is deteriorated. Even if the coefficient of friction between the prepreg and the mold surface is lower than the coefficient of friction between the prepregs, the flow is limited if the coefficient of friction between the prepreg and the mold surface is large. The fiber reinforced plastic that exhibits the best surface quality can be obtained by pressurizing within the range of the temperature ± 10 ° C. at which the friction coefficient is minimum.
なお、成形時間を短縮する観点からは、加温したプリプレグ積層体を加圧してから所定の温度まで昇温させるまでに要する時間は、短いほどよく、加圧後にプリプレグ積層体が十分に伸張した段階で所定の温度まで昇温させるのがよい。また、前記した、加圧する際の温度から所定の温度までの昇温は、加圧する際の温度から所定の温度までの温度差ΔＴが１０℃以上となる温度上昇を意味する。一方で、昇温する温度差ΔＴが大きくなるに伴って、昇温時間も長くなるため、成形時間を短縮する観点から好ましくは、昇温する温度差ΔＴが８０℃を超えない、さらに好ましくは４０℃を超えないように、昇温後の保持する温度を決めるのがよい。 From the viewpoint of shortening the molding time, it is better that the time required for raising the temperature to a predetermined temperature after pressurizing the heated prepreg laminate is as short as possible, and the prepreg laminate is sufficiently stretched after pressurization. The temperature should be raised to a predetermined temperature in stages. Moreover, the above-mentioned temperature rise from the temperature at the time of pressurization to a predetermined temperature means a temperature increase at which the temperature difference ΔT from the temperature at the time of pressurization to the predetermined temperature becomes 10 ° C. or more. On the other hand, as the temperature difference ΔT for increasing the temperature increases, the temperature increasing time also becomes longer. Therefore, from the viewpoint of shortening the molding time, the temperature difference ΔT for increasing the temperature preferably does not exceed 80 ° C., more preferably It is preferable to determine the temperature to be maintained after the temperature rise so as not to exceed 40 ° C.
本発明では、プリプレグ積層体を加圧して賦形する温度と、昇温してマトリックス樹脂を硬化させる温度との２段階で温度を上げ、繊維強化プラスチックを成形する。そして、プリプレグ積層体を加圧して賦形する温度を制御して、賦形に適した温度にてプリプレグ積層体を加熱加圧し賦形する。これにより、一定温度でマトリックス樹脂を硬化させる工程にくらべて、短時間で繊維強化プラスチックを成形することが可能となる。 In the present invention, the fiber-reinforced plastic is molded by raising the temperature in two stages: the temperature at which the prepreg laminate is pressurized and shaped, and the temperature at which the matrix resin is cured by raising the temperature. And the temperature which pressurizes and shapes a prepreg laminated body is controlled, and a prepreg laminated body is heat-pressed and shaped at the temperature suitable for shaping. This makes it possible to mold the fiber reinforced plastic in a short time compared to the process of curing the matrix resin at a constant temperature.
本発明における摩擦係数は、図１に示すように２枚の部材４の間に１枚の中央層３を挟んだ試験片を作製し、挟まれた中央層を引き抜く際に得られる荷重を、面外から垂直に押しつける荷重（垂直荷重）の２倍で割って得られる値で定義する。２倍であるのは摩擦抵抗を受ける中央層と部材との界面が２箇所存在するからである。部材４を成形型と同材質、同表面粗さとし、中央層３としてプリプレグを用いて測定した際の値がプリプレグと型面との摩擦係数となる。成形型に滑剤や離型剤などを塗布するなどの処理をして成形を行う場合には、部材４に成形型と同様の処理を行って、部材４の表面状態を成形型と同一の条件として、試験を行う。プリプレグ積層体と成形型との間にフィルムなどを介する条件で成形する場合は、フィルムがプリプレグ積層体と同様に伸張して型面とフィルムとの間が滑る際には、中央層３としてフィルムを用い、フィルムと部材４との摩擦係数をプリプレグと型面との摩擦係数とすればよく、一方で、フィルムと型が一体化し、プリプレグが伸張してプリプレグとフィルムの間が滑る際は、成形型の表面はフィルムであると見なし、部材４としてフィルムを用いて測定した摩擦係数を、プリプレグと型面との摩擦係数とする。また部材４としてプリプレグを用い、部材３もプリプレグを用いて測定した際の値がプリプレグ同士の摩擦係数である。 As shown in FIG. 1, the friction coefficient in the present invention is a test piece in which one central layer 3 is sandwiched between two members 4 and the load obtained when the sandwiched central layer is pulled out, It is defined by the value obtained by dividing by 2 times the load (vertical load) pressed vertically from the outside of the plane. The reason for the double is that there are two interfaces between the central layer and the member that receive frictional resistance. The member 4 is made of the same material and the same surface roughness as the mold, and the value measured using the prepreg as the central layer 3 is the friction coefficient between the prepreg and the mold surface. When forming by performing a process such as applying a lubricant or a mold release agent to the mold, the member 4 is subjected to the same process as the mold, and the surface condition of the member 4 is the same as that of the mold. As a test. When the film is formed between the prepreg laminate and the molding die under the condition that a film or the like is interposed, when the film stretches like the prepreg laminate and slides between the mold surface and the film, the film is used as the central layer 3. And the friction coefficient between the film and the member 4 may be the friction coefficient between the prepreg and the mold surface. On the other hand, when the film and the mold are integrated and the prepreg expands and slides between the prepreg and the film, The surface of the mold is regarded as a film, and the friction coefficient measured using the film as the member 4 is defined as the friction coefficient between the prepreg and the mold surface. Moreover, a prepreg is used as the member 4, and the value when the member 3 is also measured using the prepreg is a friction coefficient between the prepregs.
試験法としては、中央層３を切り出し（中央層３がプリプレグの場合には、繊維方向に長尺となるよう切り出す）、幅３０ｍｍ（中央層３がプリプレグの場合には、繊維直交方向）、長さ６０ｍｍ（中央層３がプリプレグの場合には、繊維方向）の範囲で、２枚の部材４の間に中央層３がオーバーラップするように、２枚の部材４と中央層３の３枚を積層する。なお、繊維方向とは、強化繊維の配向方向を意味し、繊維直交方向とは、強化繊維の配向方向に垂直な方向を意味する。 As a test method, the central layer 3 is cut out (when the central layer 3 is a prepreg, it is cut out so as to be long in the fiber direction), and the width is 30 mm (when the central layer 3 is a prepreg, the direction perpendicular to the fiber), In the range of 60 mm in length (in the fiber direction when the central layer 3 is a prepreg), the two members 4 and the central layer 3 3 so that the central layer 3 overlaps between the two members 4. Laminate the sheets. In addition, a fiber direction means the orientation direction of a reinforced fiber, and a fiber orthogonal direction means a direction perpendicular | vertical to the orientation direction of a reinforced fiber.
部材４と中央層３がともにプリプレグである場合は、それらが同一繊維方向となるように積層する。そして、中央層３のオーバーラップ部に接するように幅３０ｍｍの中央層３と同一材料の（中央層３がプリプレグの場合には、同一繊維方向）スペーサー５を設置して試験片を作製する。引抜きとともにオーバーラップ部の面積が減り、圧板１で加圧する領域が偏ることから、圧板が片当たりして局所的に高い荷重が加わる可能性があるため、引抜きと逆方向にスペーサーを配置し、圧板が傾かないようにする。 When the member 4 and the center layer 3 are both prepregs, they are laminated so that they are in the same fiber direction. Then, a spacer 5 made of the same material as that of the central layer 3 having a width of 30 mm (in the same fiber direction when the central layer 3 is a prepreg) is installed so as to be in contact with the overlap portion of the central layer 3 to prepare a test piece. Since the area of the overlap part decreases with the drawing and the area to be pressed with the pressure plate 1 is biased, there is a possibility that a high load may be applied locally due to the pressure plate hitting, so a spacer is arranged in the direction opposite to the drawing, Prevent the platen from tilting.
オーバーラップ部とスペーサーの長さ２０ｍｍの範囲まで（幅３０ｍｍ、長さ８０ｍｍの範囲）熱源を有した圧板１で試験温度に温調しながら一定の垂直荷重を試験中加え続ける。かかる試験片に試験温度に温調した圧板で垂直荷重を加えて一定時間保持した後に、中央層を長尺方向（中央層３がプリプレグの場合には、繊維方向）に一定の引抜速度で引抜き、引抜荷重をオーバーラップ部（試験開始時には幅３０ｍｍ、長さ８０ｍｍの範囲）に加わる垂直荷重で割ったものを摩擦係数として計算する。ここで引抜きともに中央層が垂直荷重を受けるオーバーラップ部の面積が減少するため、適宜引抜変位で換算したオーバーラップ部の面積（幅３０ｍｍ、長さ６０ｍｍ−引抜変位の範囲）とスペーサーで荷重を受けている面積（幅３０ｍｍ、長さ２０ｍｍの範囲）を足しあわせた面積で垂直荷重を受けるとしてオーバーラップ部に加わる垂直荷重を比例計算し、その垂直荷重の２倍で引抜荷重を割ったものを摩擦係数とする。 A constant vertical load is continuously applied during the test while adjusting the temperature to the test temperature with the pressure plate 1 having a heat source up to a range of 20 mm in length of the overlap portion and the spacer (30 mm in width and 80 mm in length). After applying a vertical load to the test piece with a pressure plate adjusted to the test temperature and holding it for a certain period of time, the central layer is drawn in the longitudinal direction (in the fiber direction when the central layer 3 is a prepreg) at a constant drawing speed. The frictional coefficient is calculated by dividing the pulling load by the vertical load applied to the overlap portion (30 mm width and 80 mm length at the start of the test). Here, since the area of the overlap part where the center layer receives the vertical load is reduced in both the drawing and the area of the overlap part (width 30 mm, length 60 mm-the range of the drawing displacement) converted by the drawing displacement as appropriate, the load is applied by the spacer. The vertical load applied to the overlap part is calculated proportionally to receive the vertical load with the total area (width 30mm, length 20mm), and the pulling load is divided by twice the vertical load. Is the coefficient of friction.
摩擦係数は温度だけでなく、引抜速度、垂直応力、時間経過とともに変化する。本発明において、試験片に、温調した圧板を１９２Ｎの垂直荷重を加えて加圧し１分保持後に引抜きを開始する。引抜速度は０．１７ｍｍ／分とし、引抜き開始後３分における引抜荷重をその時点でオーバーラップ部に加わる垂直荷重で割ったものを摩擦係数として取得し、本試験を５個の試験片で繰り返してその平均値を本発明における摩擦係数として定義する。 The coefficient of friction changes not only with temperature but also with drawing speed, normal stress, and time. In the present invention, a temperature-controlled pressure plate is pressed against the test piece by applying a vertical load of 192 N, and after one minute is held, drawing is started. The drawing speed is 0.17 mm / min, and the pulling load at 3 minutes after the start of drawing is divided by the vertical load applied to the overlap at that time to obtain the friction coefficient, and this test is repeated with five test pieces. The average value is defined as the friction coefficient in the present invention.
本発明において、賦形時にプリプレグ積層体を加温する温度は、前記した摩擦係数の測定方法に従って、試験温度を１０℃きざみで変えた際の、各試験温度において、プリプレグと型面との摩擦係数と、プリプレグ同士の摩擦係数とを比較して、プリプレグと型面との摩擦係数がプリプレグ同士の摩擦係数より小さくなる温度であって、プリプレグと型面との摩擦係数が最小となる温度とする。すなわち、プリプレグと型面との摩擦係数が最小となる温度±１０℃とは、試験温度を１０℃きざみで変えて測定したプリプレグと型面との摩擦係数が、最小の値を示す、きざみ温度を意味する。 In the present invention, the temperature at which the prepreg laminate is heated during shaping is the friction between the prepreg and the mold surface at each test temperature when the test temperature is changed in increments of 10 ° C. according to the method for measuring the friction coefficient. The coefficient is a temperature at which the friction coefficient between the prepreg and the mold surface is smaller than the friction coefficient between the prepregs, and the temperature at which the friction coefficient between the prepreg and the mold surface is minimized. To do. That is, the temperature ± 10 ° C. at which the coefficient of friction between the prepreg and the mold surface is the minimum is the step temperature at which the coefficient of friction between the prepreg and the mold surface measured by changing the test temperature in steps of 10 ° C. shows the minimum value. Means.
本発明の好ましい実施様態として、プリプレグ積層体の加圧を両面型で型締めして行うのがよい。凹凸部や複合曲面といった三次元複雑形状の成形は、強制力が高い雌雄一対の両面型を用いることで良形状追従性、良表面品位を得ることができる。また、両面型とすることで、熱容量の大きな型から迅速にプリプレグ積層体が均一加熱することができる。 As a preferred embodiment of the present invention, the prepreg laminate is preferably pressed by a double-sided mold. In forming a three-dimensional complicated shape such as an uneven portion or a complex curved surface, good shape followability and good surface quality can be obtained by using a pair of male and female high-force forcing. Moreover, by using a double-sided mold, the prepreg laminate can be uniformly heated quickly from a mold having a large heat capacity.
好ましくは、プリプレグ積層体の加圧を両面型で行うに際し、プリプレグ積層体を、型締めまでいずれの型面にも接触させずに配置するのがよい。プリプレグ積層体を温調された型面に配置した状態で、加温した場合、厚物のプリプレグ積層体の場合、プリプレグ積層体に温度ムラ、マトリックス樹脂の硬化ムラが生じるため、加温中に型面と接するプリプレグ積層体の最表層が硬化し、良好な流動性が発現しないことがある。ブランクフォルダなどを用いて、プリプレグ積層体の周縁部を把持することで、型締めまでいずれの型面にも接触させずに配置することができ、型締めの際に、両面型内に引き込みながら型締めをするとともに、加圧することで、型締めまでいずれの型面にも接触させずに、成形が可能となる。さらに好ましくは、ブランクフォルダに把持されたプリプレグ積層体を、温風、ＩＲヒータで温調するのがよい。 Preferably, when pressurizing the prepreg laminate with a double-sided mold, the prepreg laminate is preferably arranged without contacting any mold surface until clamping. When heated in a state where the prepreg laminate is placed on a temperature-controlled mold surface, in the case of a thick prepreg laminate, temperature unevenness and uneven curing of the matrix resin occur in the prepreg laminate. The outermost layer of the prepreg laminate that is in contact with the mold surface may harden and may not exhibit good fluidity. Using a blank folder, etc., by gripping the peripheral edge of the prepreg laminate, it can be placed without contacting any mold surface until mold clamping, while pulling into the double-sided mold during mold clamping By clamping and pressurizing, molding is possible without contacting any mold surface until clamping. More preferably, the temperature of the prepreg laminate held by the blank folder is adjusted with warm air or an IR heater.
好ましくは、本発明では、基材として、一方向に引き揃えられた強化繊維に熱硬化性樹脂を含浸させてなるプリプレグを用いるのがよい。強化繊維を織物としてマトリックス樹脂を含浸せしめた織物プリプレグを用いた場合、面内方向にせん断変形することで形状追従性は高いものの、強化繊維が厚み方向にうねった構成であるため、強化繊維が有する高弾性率、高強度の特性を十分に利用することができず、実現できる力学特性に限界がある。一方で、一方向に強化繊維が配向することで、強化繊維を最密充填可能であり、また真直に引き揃えられているため、強化繊維が持つ高い力学特性を最大限に活用できる。 Preferably, in the present invention, a prepreg formed by impregnating a reinforcing fiber aligned in one direction with a thermosetting resin is used as the base material. When using a woven prepreg impregnated with a matrix resin as a reinforced fiber, the shape followability is high by shear deformation in the in-plane direction, but the reinforced fiber is undulated in the thickness direction. The high elastic modulus and high strength characteristics possessed cannot be fully utilized, and there are limits to the mechanical characteristics that can be realized. On the other hand, since the reinforcing fibers are oriented in one direction, the reinforcing fibers can be packed most closely and are straightly arranged, so that the high mechanical properties of the reinforcing fibers can be utilized to the maximum.
さらに好ましくは、一方向に強化繊維が引き揃ったプリプレグにて構成されるプリプレグ積層体のうち、少なくとも一層のプリプレグが、複数の切込によって一部が繊維長さ１０〜３００ｍｍの強化繊維で構成された切込プリプレグであるようにするのがよい。連続繊維を有するプリプレグを三次元複雑形状へ賦形する場合、表面形状を覆いきれない箇所で強化繊維の突っ張りが、プリプレグが余った箇所で強化繊維が座屈して皺が発生する懸念がある。複数の切込によって、繊維が不連続となるためプリプレグは繊維方向へ伸張することができる。表面形状を覆いきれない箇所、例えば、圧力の加わり難いコーナー部のみに切込を挿入することで、プリプレグ積層体の形状追従性を制御することができる。切込によって分断された強化繊維の繊維長さＬを３００ｍｍ以下とすることにより、前記した強化繊維の突っ張りを効果的に抑制することができる。繊維長さＬを１０ｍｍ未満とすると、切込同士の距離が近づくため、繊維強化プラスチックに荷重が負荷された際、クラックが連結しやすく、強度が低下するという問題がある。形状追従性と力学特性との関係を鑑みると、さらに好ましくは強化繊維の繊維長さＬが１５〜１００ｍｍの範囲内である。さらに好ましくは、１０ｍｍ以下の繊維が配向している面積が、プリプレグ層に占める割合の５％より小さいのがよい。なお、繊維長さＬとは、図２〜６に示すように、任意の切込と、繊維方向に最近接の切込（対になる切込）とにより分断される繊維長さである。 More preferably, at least one prepreg of the prepreg laminate composed of prepregs in which reinforcing fibers are aligned in one direction is composed of reinforcing fibers having a fiber length of 10 to 300 mm by a plurality of cuts. It is good to make it the cut prepreg made. When a prepreg having continuous fibers is shaped into a three-dimensional complex shape, there is a concern that the reinforcing fiber is stretched at a location where the surface shape cannot be covered, and the reinforcing fiber is buckled at a location where the prepreg is left, resulting in wrinkles. Since the fiber becomes discontinuous due to the plurality of cuts, the prepreg can be extended in the fiber direction. The shape following property of the prepreg laminate can be controlled by inserting a cut into only a portion where the surface shape cannot be covered, for example, a corner portion where pressure is hardly applied. By setting the fiber length L of the reinforcing fiber divided by the cutting to 300 mm or less, the above-described stretching of the reinforcing fiber can be effectively suppressed. When the fiber length L is less than 10 mm, since the distance between the cuts approaches, there is a problem that when a load is applied to the fiber reinforced plastic, cracks are easily connected and the strength is reduced. Considering the relationship between the shape followability and the mechanical properties, the fiber length L of the reinforcing fiber is more preferably in the range of 15 to 100 mm. More preferably, the area in which fibers of 10 mm or less are oriented is smaller than 5% of the proportion of the prepreg layer. In addition, the fiber length L is a fiber length divided | segmented by arbitrary notch | incisions and the notch | nearest incision (cutting which becomes a pair) in a fiber direction, as shown to FIGS.
本発明が実施される形態として、プリプレグ積層体の投影面積よりも、製造される繊維強化プラスチックの投影面積が大きくなる繊維強化プラスチックを製造する場合、成形中におけるプリプレグ積層体の伸張方向と、強化繊維の配向方向とのなす角度αが±２０°以内である層に切込プリプレグを用いるのがよい。それにより、伸張方向に繊維が突っ張らず、良好な形状追従性を実現できる。プリプレグ積層体の投影面積よりも、製造される繊維強化プラスチックの投影面積が大きくなる、とは、例えば、プリプレグ積層体の投影面積よりも広いキャビティを有する雌雄一対の両面型を用いて、プリプレグ積層体をその面内方向に押し広げて（伸張させて）、加圧成形する方法が挙げられる。 As an embodiment in which the present invention is implemented, when producing a fiber reinforced plastic in which the projected area of the fiber reinforced plastic to be produced is larger than the projected area of the prepreg laminate, the stretching direction of the prepreg laminate during molding and the reinforcement It is preferable to use a cut prepreg in a layer whose angle α formed with the fiber orientation direction is within ± 20 °. Thereby, the fiber does not stretch in the extending direction, and good shape following property can be realized. The projected area of the fiber reinforced plastic produced is larger than the projected area of the prepreg laminate, for example, using a pair of male and female double-sided molds having a cavity wider than the projected area of the prepreg laminate. There is a method in which the body is pressed (stretched) in the in-plane direction and pressure-molded.
一方向に強化繊維が引き揃ったプリプレグは、成形時に繊維が流動するに際し、繊維方向と繊維直交方向との流動性に異方性が生じるため、効果的に繊維を流動させるためには、強化繊維の配向が異なる方向に積層することが重要となる。なかでも、［０／９０］ｎｓや［０／±６０］ｎｓ、［４５／０／−４５／９０］ｎｓといった等方積層で、かつ対称積層であることが、成形時の流動の均質性、および繊維強化プラスチックとして場合のそり低減を考慮すると好ましい。一方で、繊維直交方向へ伸張する場合は、マトリックス樹脂の流動により繊維が分散しやすく伸張可能であるが、繊維方向へ伸張する場合は、強化繊維の高い弾性率により十分な伸張量を確保できない。特に、伸張方向と強化繊維の配向方向とのなす角度αが±２０°以内である場合、強化繊維の高い弾性率に起因して伸張量を確保できないことから、当該層を切込プリプレグとすることで、伸張量を確保することができる。 A prepreg with reinforced fibers aligned in one direction has anisotropy in the fluidity between the fiber direction and the direction perpendicular to the fiber when the fiber flows during molding. It is important to laminate the fibers in different directions. In particular, the homogeneity of the flow during molding is an isotropic lamination such as [0/90] ns , [0 / ± 60] ns , and [45/0 / −45 / 90] ns , and a symmetric lamination. In view of the reduction of warpage in the case of fiber reinforced plastic, it is preferable. On the other hand, when stretched in the direction perpendicular to the fiber, the fibers can be easily dispersed and stretched by the flow of the matrix resin, but when stretched in the fiber direction, a sufficient stretch amount cannot be secured due to the high elastic modulus of the reinforcing fiber. . In particular, when the angle α between the stretching direction and the orientation direction of the reinforcing fiber is within ± 20 °, the stretch amount cannot be secured due to the high elastic modulus of the reinforcing fiber, so that the layer is a cut prepreg. Thus, the amount of expansion can be ensured.
本発明が実施される形態として、成形前のプリプレグ積層体が平板状であり、製造される繊維強化プラスチックが少なくとも一部に曲面を有する三次元形状であって、成形中に曲げが加わるプリプレグ積層体の中立軸よりも引張側の層に切込プリプレグを用いるのがよい。引張が加わる層が突っ張らないことで、中立軸よりも圧縮側の層に加わる、皺を発生させる圧縮力を低減させることができる。 As an embodiment in which the present invention is implemented, the prepreg laminate before molding is a flat plate shape, and the fiber-reinforced plastic to be manufactured is a three-dimensional shape having a curved surface at least partially, and bending is applied during molding It is preferable to use a cut prepreg in the layer on the tension side of the neutral axis of the body. Since the layer to which tension is applied does not stretch, the compressive force that generates wrinkles applied to the layer on the compression side of the neutral axis can be reduced.
本発明における切込プリプレグは、力学特性の観点から好ましくは、少なくとも一部に強化繊維を横切る方向へ断続的な切込が複数設けられており、切込を強化繊維の配向方向に垂直な方向に投影した長さ、いわゆる投影長さＷｓが３０μｍ〜１．５ｍｍの範囲内であるのがよく、強化繊維の長手方向に断続的な切込に囲まれる領域において実質的に強化繊維のすべてが切込により分断されているのがよい。対となる切込によって全ての繊維が所定の長さ以下となることで、三次元形状への追従性を担保し、強化繊維の突っ張りを抑制することができる。Ｗｓを小さくすることにより、一つ一つの切込により分断される繊維量が減り、強度向上が見込まれる。特に、Ｗｓを１．５ｍｍ以下とすることで、大きな強度向上が見込まれる。一方で、Ｗｓが３０μｍより小さい場合、切込位置の制御が難しく、対となる切込によって全ての繊維を所定の長さ以下とするのが難しく、成形時に強化繊維の突っ張りなどが生じることがある。ここで、“投影長さＷｓ”とは、図２、４、５、６に示すように、プリプレグ層の面内において、切込を強化繊維の配向方向に垂直な方向（繊維直交方向８）を投影面として、切込から該投影面に垂直（繊維方向７）に投影した際の長さを指す。 The cutting prepreg in the present invention is preferably provided with a plurality of intermittent cuts in a direction crossing the reinforcing fibers at least partially in view of mechanical properties, and the cutting is in a direction perpendicular to the orientation direction of the reinforcing fibers. The projection length Ws should be within the range of 30 μm to 1.5 mm, so that substantially all of the reinforcing fibers are substantially surrounded by the intermittent cuts in the longitudinal direction of the reinforcing fibers. It is good that it is divided by cutting. By making all the fibers have a predetermined length or less by the pair of cuts, it is possible to ensure followability to the three-dimensional shape and suppress the tension of the reinforcing fibers. By reducing Ws, the amount of fibers cut by each cutting is reduced, and strength improvement is expected. In particular, when Ws is 1.5 mm or less, a great improvement in strength is expected. On the other hand, when Ws is smaller than 30 μm, it is difficult to control the cutting position, and it is difficult to make all the fibers have a predetermined length or less due to the pair of cuttings, and the reinforcing fibers may be stretched during molding. is there. Here, as shown in FIGS. 2, 4, 5, and 6, the “projected length Ws” is a direction perpendicular to the orientation direction of the reinforcing fibers (fiber orthogonal direction 8) in the plane of the prepreg layer. Is the projection plane, and refers to the length when projected perpendicularly to the projection plane from the cut (fiber direction 7).
本発明の好ましい実施態様として、切込の切込方向と強化繊維の配向方向とのなす角をθとしたとき、θの絶対値が２〜２５°の範囲内であるのがよい。図３に示すように、連続切込の場合は、繊維長さＬを一定にコントロールすることができ、力学特性、三次元形状追従性のバラツキを低減することができる。図４〜６に示すように、断続的な切込の場合にはθの絶対値が前記範囲であることにより、切込長さＹの大きさに対して、投影長さＷｓを小さくすることができるため、１．５ｍｍ以下という極小の切込を工業的に安定して設けることができ、また積層時に、連続切込であってもプリプレグがばらばらになり難く、プリプレグとしての取り扱い性にも優れる。特にθの絶対値が２５°以下であることで力学特性、中でも引張強度の向上が著しい。一方、θの絶対値は２°より小さいと切込を安定して入れることが難しくなる。すなわち、繊維の配向方向に対して切込方向が寝てくると、切込を入れる際、繊維が刃から逃げやすく、また、図４の例でいうと切込の列１３同士の最短距離が小さくなり、切込の位置精度を担保しながら挿入することが難しくなる。切込の制御のしやすさと力学特性との関係を鑑みると、さらに好ましくは５〜１５°の範囲内である。さらに好ましくは、投影長さＷｓが３０μｍ〜１．５ｍｍの範囲内で、かつ、θの絶対値が２〜２５°の範囲内であるのがよい。 As a preferred embodiment of the present invention, when the angle formed by the incision direction of the incision and the orientation direction of the reinforcing fibers is θ, the absolute value of θ is preferably in the range of 2 to 25 °. As shown in FIG. 3, in the case of continuous cutting, the fiber length L can be controlled to be constant, and variations in mechanical characteristics and three-dimensional shape followability can be reduced. As shown in FIGS. 4 to 6, in the case of intermittent cutting, the projection length Ws is made smaller than the cutting length Y because the absolute value of θ is in the above range. Therefore, it is possible to provide industrially stable cuts as small as 1.5 mm or less, and even during continuous cutting, the prepreg is unlikely to break apart and is easy to handle as a prepreg. Excellent. In particular, when the absolute value of θ is 25 ° or less, the mechanical properties, particularly the tensile strength, are remarkably improved. On the other hand, if the absolute value of θ is smaller than 2 °, it becomes difficult to make a stable cut. That is, when the incision direction falls with respect to the fiber orientation direction, the fiber easily escapes from the blade when making the incision, and the shortest distance between the incision rows 13 in the example of FIG. It becomes small and it becomes difficult to insert while ensuring the positional accuracy of the cut. In view of the relationship between the ease of controlling the cutting and the mechanical characteristics, it is more preferably in the range of 5 to 15 °. More preferably, the projection length Ws is in the range of 30 μm to 1.5 mm, and the absolute value of θ is in the range of 2 to 25 °.
切込プリプレグにおける好ましいカットパターンとしては、図４のように、断続的な切込が直線状かつ平行に挿入されて列１３を形成し、列間の距離Ｘが１〜５ｍｍの範囲内であるのがよい。繊維長さＬが同一の場合、同一方向の直線状な切込とすることで切込同士の最短距離を最大化することができる。加えて切込挿入をミシン目の回転丸刃を一直線上に転がしたり、レーザー加工用のパルスレーザーを一直線上に高速で走査したりすることでパルス周期に対応する切込を挿入するなど、生産性の高い切込挿入法を期待できる。 As a preferable cut pattern in the cut prepreg, as shown in FIG. 4, intermittent cuts are inserted linearly and in parallel to form rows 13, and the distance X between rows is in the range of 1 to 5 mm. It is good. When the fiber length L is the same, the shortest distance between the cuts can be maximized by making the straight cuts in the same direction. In addition, the incision is inserted by rolling the perforated rotating round blade on a straight line, or by inserting a cut corresponding to the pulse period by scanning a laser pulse laser at a high speed on a straight line. A highly efficient cutting insertion method can be expected.
別の好ましいカットパターンとしては、図５に示すように、断続的な切込が直線状に挿入され、θの絶対値が実質的に同一であり、正と負の角となる切込が略半数ずつであるのがよい。得られた切込プリプレグを積層する際、斜め切込が一方向の場合には、同一繊維方向のプリプレグであっても、プリプレグを表から見るか裏から見るかで異なる切込の方向となるため、繊維強化プラスチック製造時に、毎回切込の方向が同じようになるように、もしくは同じ繊維方向で切込方向が異なるものを同じ枚数積層するための積層手順を制御する手間が増える可能性がある。繊維方向からの切込の傾きの絶対値が同一であり、正と負の角となる切込が略半数となるカットパターンであれば、通常の連続繊維プリプレグ同様の扱いで積層が可能となる。 As another preferred cut pattern, as shown in FIG. 5, intermittent cuts are inserted in a straight line, the absolute values of θ are substantially the same, and cuts having positive and negative angles are substantially omitted. It should be half. When laminating the obtained cut prepreg, if the diagonal cut is in one direction, even if the prepreg is in the same fiber direction, the direction of the cut differs depending on whether the prepreg is viewed from the front or the back. Therefore, when manufacturing fiber reinforced plastics, there is a possibility that the labor for controlling the laminating procedure for laminating the same number of the same fiber direction with the same cutting direction so that the cutting direction will be the same every time will be increased. is there. If the absolute value of the inclination of the cut from the fiber direction is the same, and the cut pattern is a half of the positive and negative corner cuts, it is possible to laminate in the same manner as a normal continuous fiber prepreg .
切込プリプレグの好ましい様態として、図５に示すように、任意の切込と近接する切込のうち、θの正負が同一である切込よりも最短距離が近いθの正負が異なる切込が４つ以上存在するのがよい。三次元形状追従時にプリプレグの切込挿入部は、切込角度と繊維方向との関係で繊維端部の動きが決まるため、近接する切込同士は同形状、逆方向の角度であることで、マクロに見た場合、成形後の面内の等方性が担保される。 As a preferred mode of the cutting prepreg, as shown in FIG. 5, among the cuttings close to an arbitrary cutting, there is a cutting with different positive and negative values of θ that is the shortest distance than a cutting with the same positive and negative values of θ. There should be four or more. Since the movement of the fiber end is determined by the relationship between the cutting angle and the fiber direction, the adjacent cuttings have the same shape, an angle in the opposite direction, because the prepreg cut insertion part at the time of three-dimensional shape tracking When viewed macroscopically, in-plane isotropy after molding is ensured.
さらに、切込プリプレグの好ましい態様として、図６に示すように、断続的な切込が直線かつ実質的に同一の長さＹで挿入され、近接する切込同士の最短距離が切込の長さＹよりも長いのがよい。力学特性の観点から、繊維の不連続点である切込同士がクラックにより連結された際、繊維強化プラスチックは破壊する。面内の切込同士の距離を離したカットパターンとすることで、少なくとも同一面内でのクラック連結を抑制する効果があり、強度が向上する。 Furthermore, as a preferable aspect of the cut prepreg, as shown in FIG. 6, intermittent cuts are inserted with straight lines and substantially the same length Y, and the shortest distance between adjacent cuts is the cut length. It should be longer than Y. From the viewpoint of mechanical properties, the fiber reinforced plastic breaks when the cuts that are discontinuities of the fibers are connected by cracks. By using a cut pattern in which in-plane notches are separated from each other, there is an effect of suppressing crack connection in at least the same plane, and the strength is improved.
以下、実施例により本発明をさらに具体的に説明するが、本発明は、実施例に記載の発明に限定されるものではない。まず、実施例で用いた、プリプレグ同士の摩擦係数およびプリプレグと型面との摩擦係数の測定方法、繊維強化プラスチックの成形方法およびプリプレグの作製方法を記す。 EXAMPLES Hereinafter, although an Example demonstrates this invention further more concretely, this invention is not limited to the invention as described in an Example. First, the method for measuring the friction coefficient between prepregs and the friction coefficient between the prepreg and the mold surface, the molding method of the fiber reinforced plastic, and the preparation method of the prepreg used in the examples will be described.
（１）プリプレグ同士の摩擦係数の測定方法
次の（ａ）〜（ｃ）の操作により、プリプレグ同士の摩擦係数を測定した。
(1) Method for measuring friction coefficient between prepregs The friction coefficient between prepregs was measured by the following operations (a) to (c).
（ａ）０°を長さ方向として、幅４０ｍｍ、長さ１５０ｍｍに裁断した１層目のプリプレグに、幅３０ｍｍ、長さ１５０ｍｍに裁断した２層目のプリプレグを幅３０ｍｍ、長さ６０ｍｍの範囲でオーバーラップするように積層し、さらに２層目のオーバーラップ部に接するように幅３０ｍｍ、長さ２０ｍｍのスペーサー用プリプレグを積層した後、幅４０ｍｍ、長さ１５０ｍｍの３層目のプリプレグを１層目と重なるように積層して試験片を作製した。その後、幅４０ｍｍ、長さ１５０ｍｍの離型紙を１層目および３層目の外側に重なるよう試験片に貼り付けた。 (A) Range of 30 mm in width and 60 mm in length of the second prepreg cut to 30 mm in width and 150 mm in length to the first prepreg cut to 40 mm in width and 150 mm in length with 0 ° as the length direction After stacking a spacer prepreg 30 mm wide and 20 mm long so as to be in contact with the overlap portion of the second layer, a third layer prepreg 40 mm wide and 150 mm long 1 A test piece was prepared by stacking so as to overlap the layer. Thereafter, a release paper having a width of 40 mm and a length of 150 mm was attached to the test piece so as to overlap the first and third layers.
（ｂ）オーバーラップ部とスペーサー長さを含めた範囲（幅３０ｍｍ、長さ８０ｍｍの範囲）に加熱源を有した上下の圧板を所定の温度に温調した。 (B) The upper and lower pressure plates having the heating source in the range including the overlap portion and the spacer length (range of width 30 mm, length 80 mm) were adjusted to a predetermined temperature.
（ｃ）所定の温度で温調した上下の圧板で、（ａ）で作製した、離型紙を貼り付けた試験片を挟み、１９２Ｎの一定垂直荷重を加えて、１分後に、２層目のプリプレグを繊維方向に引抜速度０．１７ｍｍ／分で引抜き、引抜荷重をオーバーラップ部に加わる垂直荷重の２倍で割ったものをプリプレグ同士の個別の摩擦係数として計算した。２倍であるのは、摩擦抵抗を受けるプリプレグ表面が２箇所存在するからである。引抜荷重としては、試験３分後、すなわち引抜変位０．５ｍｍにおける引抜荷重を用いた。引抜きとともに２層目のプリプレグが垂直荷重を受けるオーバーラップ部の面積が減少するため、オーバーラップ部に加わる垂直荷重は、引抜変位で次のようにして換算した。
オーバーラップ部に加わる垂直荷重＝１９２Ｎ×（６０ｍｍ−引抜変位）÷（８０ｍｍ−引抜変位）
(C) Between the upper and lower pressure plates temperature-controlled at a predetermined temperature, the test piece prepared in (a) with the release paper attached is sandwiched, a constant vertical load of 192N is applied, and after 1 minute, the second layer The prepreg was drawn in the fiber direction at a drawing speed of 0.17 mm / min, and the value obtained by dividing the drawing load by twice the vertical load applied to the overlap portion was calculated as the individual friction coefficient between the prepregs. The reason for the double is that there are two prepreg surfaces that receive frictional resistance. As the pull-out load, the pull-out load after 3 minutes of the test, that is, the pull-out displacement of 0.5 mm was used. Since the area of the overlap portion where the second layer prepreg receives a vertical load decreases with the drawing, the vertical load applied to the overlap portion is converted as follows by the drawing displacement.
Vertical load applied to the overlap part = 192N x (60mm-extraction displacement) / (80mm-extraction displacement)
すなわち、引抜変位０．５ｍｍにおけるオーバーラップ部に加わる垂直荷重は、１９２×（６０−０．５）÷（８０−０．５）＝１４３．７となる。 That is, the vertical load applied to the overlap portion at the drawing displacement of 0.5 mm is 192 × (60−0.5) ÷ (80−0.5) = 143.7.
５個の試験片について、個別の摩擦係数を測定し、その平均値を、プリプレグ同士の摩擦係数とした。 About five test pieces, the individual friction coefficient was measured and the average value was made into the friction coefficient between prepregs.
（２）プリプレグと型面との摩擦係数の測定方法
次の（ａ）〜（ｃ）の操作によりプリプレグと型面との摩擦係数を測定した。
(2) Method of measuring friction coefficient between prepreg and mold surface The friction coefficient between the prepreg and the mold surface was measured by the following operations (a) to (c).
（ａ）長辺を長さ方向として、幅４０ｍｍ、長さ１５０ｍｍの１層目の金属板（材質：ＳＳ４００、算術平均粗さ：３．２）に、０°を長さ方向として、幅３０ｍｍ、長さ１５０ｍｍに裁断したプリプレグを幅３０ｍｍ、長さ６０ｍｍの範囲でオーバーラップするように積層し、さらにオーバーラップ部に接するように幅３０ｍｍ、長さ２０ｍｍのスペーサー用プリプレグを積層した後、幅４０ｍｍ、長さ１５０ｍｍの３層目の金属板（材質：ＳＳ４００、算術平均粗さ：３．２）を１層目と重なるように積層して試験片を作製した。その後、幅４０ｍｍ、長さ１５０ｍｍの離型紙を１層目および３層目の外側に重なるよう貼り付けた。 (A) The first side metal plate (material: SS400, arithmetic average roughness: 3.2) having a width of 40 mm and a length of 150 mm with the long side as the length direction, and a width of 30 mm with 0 ° as the length direction The prepregs cut to a length of 150 mm are laminated so as to overlap in the range of 30 mm in width and 60 mm in length, and further, a prepreg for a spacer having a width of 30 mm and a length of 20 mm is laminated so as to be in contact with the overlap portion. A third-layer metal plate (material: SS400, arithmetic average roughness: 3.2) having a length of 40 mm and a length of 150 mm was laminated so as to overlap with the first layer to prepare a test piece. Thereafter, a release paper having a width of 40 mm and a length of 150 mm was pasted so as to overlap the first and third layers.
（ｂ）オーバーラップ部とスペーサー長さを含めた範囲（幅３０ｍｍ、長さ８０ｍｍの範囲）に加熱源を有した上下の圧板を温調した。 (B) The upper and lower pressure plates having a heating source in a range including the overlap portion and the spacer length (range of width 30 mm, length 80 mm) were temperature-controlled.
（ｃ）所定の温度で温調した上下の圧板で、（ａ）で作製した、離型紙を貼り付けた試験片を挟み、１９２Ｎの一定垂直荷重を加えて、１分後に、２層目のプリプレグを繊維方向に引抜速度０．１７ｍｍ／分で引抜き、引抜荷重をオーバーラップ部に加わる垂直荷重の２倍で割ったものをプリプレグと型面との個別の摩擦係数として計算した。２倍であるのは、摩擦抵抗を受けるプリプレグ表面が２箇所存在するからである。引抜荷重としては、試験３分後、すなわち引抜変位０．５ｍｍにおける引抜荷重を用いた。引き抜きとともに２層目のプリプレグが垂直荷重を受けるオーバーラップ部の面積が減少するため、オーバーラップ部に加わる垂直荷重は、引抜変位で次のようにして換算した。
オーバーラップ部に加わる垂直荷重＝１９２Ｎ×（６０ｍｍ−引抜変位）÷（８０ｍｍ−引抜変位）
(C) Between the upper and lower pressure plates temperature-controlled at a predetermined temperature, the test piece prepared in (a) with the release paper attached is sandwiched, a constant vertical load of 192N is applied, and after 1 minute, the second layer The prepreg was drawn in the fiber direction at a drawing speed of 0.17 mm / min, and the value obtained by dividing the drawing load by twice the vertical load applied to the overlap was calculated as the individual coefficient of friction between the prepreg and the mold surface. The reason for the double is that there are two prepreg surfaces that receive frictional resistance. As the pull-out load, the pull-out load after 3 minutes of the test, that is, the pull-out displacement of 0.5 mm was used. Since the area of the overlap portion where the second layer of the prepreg receives the vertical load decreases with the drawing, the vertical load applied to the overlap portion was converted as follows by the drawing displacement.
Vertical load applied to the overlap part = 192N x (60mm-extraction displacement) / (80mm-extraction displacement)
すなわち、引抜変位０．５ｍｍにおけるオーバーラップ部に加わる垂直荷重は、１９２×（６０−０．５）÷（８０−０．５）＝１４３．７となる。 That is, the vertical load applied to the overlap portion at the drawing displacement of 0.5 mm is 192 × (60−0.5) ÷ (80−0.5) = 143.7.
５個の試験片について、個別の摩擦係数を測定し、その平均値を、プリプレグと型面との摩擦係数とした。 With respect to the five test pieces, individual friction coefficients were measured, and the average value was taken as the friction coefficient between the prepreg and the mold surface.
（３）繊維強化プラスチックの成形方法
次の（ａ）〜（ｄ）の操作により、繊維強化プラスチックを成形した。
(3) Molding method of fiber reinforced plastic Fiber reinforced plastic was molded by the following operations (a) to (d).
（ａ）シリンダーに刃を配置したローラーカッターに、後述する（４）または（５）記載の方法で作製した一方向炭素繊維強化プリプレグを繊維方向に挿入し、断続的な直線状の切込を図６のカットパターンで挿入した。繊維長さＬは２４ｍｍ、θの絶対値は１４°でＷｓは０．２５ｍｍである。θが＋１４°の切込とθが−１４°の切込はプリプレグ中に同数挿入された。全ての切込は切込角度の正負が逆の切込が最近接で、同符号の切込角度の近接の切込より近い距離に４つの切込角度の正負が逆の切込が存在した。また、切込のあらゆる点から切込長さＹの半径内に近接の切込はなかった。切込の列１３は切込長さＹが１ｍｍである切込が１ｍｍピッチで配置されたものであり、切込の列１つおきに対応する切込によって繊維を分断し、切込プリプレグを作製した。 (A) A unidirectional carbon fiber reinforced prepreg produced by the method described in (4) or (5) described later is inserted in a fiber cutter into a roller cutter having a blade disposed on a cylinder, and intermittent linear cuts are made. Inserted with the cut pattern of FIG. The fiber length L is 24 mm, the absolute value of θ is 14 °, and Ws is 0.25 mm. The same number of cuts with a θ of + 14 ° and a cut with θ of −14 ° were inserted into the prepreg. All the incisions were closest to the incision with the opposite inversion angle, and there were incisions with the opposite in positive and negative of the four incision angles closer to the incision with the same sign. . Moreover, there was no adjacent cut within the radius of the cut length Y from every point of the cut. The incision row 13 has a cut length Y of 1 mm and is arranged at a pitch of 1 mm. The incision prepreg is cut by dividing the fibers by incisions corresponding to every other incision row. Produced.
（ｂ）得られた切込プリプレグを０°および４５°方向に１００ｍｍ角の大きさにカットし、［４５／０／−４５／９０］２ｓの積層構成で１６層疑似等方に積層し、１００ｍｍ角のプリプレグ積層体を作製した。 (B) The obtained cut prepreg was cut to a size of 100 mm square in the directions of 0 ° and 45 °, and laminated in a 16-layer pseudo-isotropic manner with a laminated structure of [ 45/0 / −45 / 90] 2s , A 100 mm square prepreg laminate was prepared.
（ｃ）成形における金型は、図７に示されるような両面型であって、下型１５は凹形状となっており、長辺方向を長さ方向として、幅方向に１００ｍｍ、長さ方向に３００ｍｍのキャビティ１７を有し、上型１４は凸形状となっており、凸部は下型のキャビティ部を埋めるような形状である両面型を用いた。金型の材質はＳＳ４００であり、プリプレグ積層体と接するツール面の表面算術平均粗さは３．２である。あらかじめ、両面型を賦形温度Ｔ１に加熱・温調した状態で、下型キャビティ部中央に、金型の長さ方向が（ｂ）で作製したプリプレグ積層体１６の０°方向となるよう、型内にプリプレグ積層体を配置した後、型を閉じ、温度Ｔ１で４分間温調をし、積層体を加温した。その際、プリプレグ積層体に加わる面圧は、上型重量分のみである。 (C) The mold in the molding is a double-sided mold as shown in FIG. 7, and the lower mold 15 has a concave shape. The long side direction is the length direction, and the width direction is 100 mm, the length direction. The upper die 14 has a convex shape, and a double-sided die having a shape that fills the cavity portion of the lower die is used. The material of the mold is SS400, and the surface arithmetic average roughness of the tool surface in contact with the prepreg laminate is 3.2. In a state where the double-sided mold is heated and adjusted to the shaping temperature T1 in advance, in the center of the lower mold cavity, the length direction of the mold is the 0 ° direction of the prepreg laminate 16 produced in (b). After the prepreg laminate was placed in the mold, the mold was closed, and the temperature was adjusted at temperature T1 for 4 minutes to warm the laminate. At that time, the surface pressure applied to the prepreg laminate is only the weight of the upper mold.
（ｄ）型を閉じて３分後、型締めして面圧３ＭＰａで加圧した。その後、成形温度Ｔ２まで昇温し、温度を保持して、プリプレグ積層体を硬化させた。一定時間経過後、両面型からプリプレグ積層体を脱型し、繊維強化プラスチックを得た。 (D) 3 minutes after closing the mold, the mold was clamped and pressurized with a surface pressure of 3 MPa. Thereafter, the temperature was raised to the molding temperature T2, the temperature was maintained, and the prepreg laminate was cured. After a certain period of time, the prepreg laminate was removed from the double-sided mold to obtain a fiber reinforced plastic.
（４）一方向炭素繊維強化プリプレグＡの作製方法
次の（ａ）〜（ｃ）の操作により、一方向炭素繊維強化プリプレグＡを作製した。
(4) Method for Producing Unidirectional Carbon Fiber Reinforced Prepreg A Unidirectional carbon fiber reinforced prepreg A was produced by the following operations (a) to (c).
（ａ）熱可塑性樹脂粒子の調製
透明ポリアミド（製品名：“グリルアミド（登録商標）”−ＴＲ５５、ＥＭＳＥＲ Ｗｅｒｋｅ社）９０質量部、エポキシ樹脂（製品名：“エピコート（登録商標）”８２８、シェル石油化学社製）７．５質量部および硬化剤（製品名：“トーマイド（登録商標）”＃２９６、フジ化成工業（株）製）２．５質量部を、クロロホルム３００質量部およびメタノール１００質量部を含有する溶媒混合物に加えて均一な溶液とした。次に、得られた均一な溶液を塗装用スプレーガンで霧化し、よく混合し、この溶液を沈殿させるためにｎ−ヘキサン３０００質量部の液体表面に向けて噴霧した。沈殿した固体を濾過により分離し、ｎ−ヘキサンで十分に洗浄し、次いで１００℃で２４時間真空乾燥させて球状エポキシ変性ナイロン粒子（熱可塑性樹脂粒子）を得た。エポキシ変性ナイロン粒子をＣＣＥテクノロジーズ社製のＣＣＥ分級機で分球した。得られた粒子の９０％粒径は２８μｍ、ＣＶ値が６０％であった。
(A) Preparation of thermoplastic resin particles 90 parts by mass of transparent polyamide (product name: “Grillamide (registered trademark)”-TR55, EMSER Werke), epoxy resin (product name: “Epicoat (registered trademark)” 828, Shell Petroleum Chemical Co., Ltd.) 7.5 parts by mass and a curing agent (product name: “Tomide (registered trademark)” # 296, Fuji Chemical Industry Co., Ltd.) 2.5 parts by mass, chloroform 300 parts by mass and methanol 100 parts by mass Was added to a solvent mixture containing a homogeneous solution. Next, the obtained uniform solution was atomized with a spray gun for coating, mixed well, and sprayed toward the liquid surface of 3000 parts by mass of n-hexane in order to precipitate this solution. The precipitated solid was separated by filtration, thoroughly washed with n-hexane, and then vacuum-dried at 100 ° C. for 24 hours to obtain spherical epoxy-modified nylon particles (thermoplastic resin particles). Epoxy-modified nylon particles were classified using a CCE classifier manufactured by CCE Technologies. The 90% particle size of the obtained particles was 28 μm, and the CV value was 60%.
（ｂ）熱硬化性樹脂組成物の調製
（i）１３質量部の“スミカエクセル(登録商標)”ＰＥＳ５００３Ｐ（住友化学(株)製）を、混練機中の６０質量部の“アラルダイト（登録商標）”ＭＹ９６５５（ハンツマン・アドバンスト・マテリアルズ社製）および４０質量部の“エポン（登録商標）”８２５（モメンティブ・スペシャルティー・ケミカルズ社製）に加えて溶解させ、次いで硬化剤として、“アラドゥール（登録商標）”９６６４−１（ハンツマン・アドバンスト・マテリアルズ社製）を４５質量部混練して熱硬化性樹脂組成物（１）を作製した。
(B) Preparation of thermosetting resin composition (i) 13 parts by mass of “SUMICA EXCEL (registered trademark)” PES5003P (manufactured by Sumitomo Chemical Co., Ltd.) was added to 60 parts by mass of “Araldite (registered trademark)”. ) “MY9655 (manufactured by Huntsman Advanced Materials)” and 40 parts by weight of “Epon (registered trademark)” 825 (manufactured by Momentive Specialty Chemicals) were dissolved and then used as a curing agent, “Aradour ( (Registered Trademark) "96664-1 (manufactured by Huntsman Advanced Materials)" was kneaded in 45 parts by mass to prepare a thermosetting resin composition (1).
（ii）１６質量部のＰＥＳ５００３Ｐを、混練機中の６０質量部の“アラルダイト（登録商標）”ＭＹ９６５５および４０質量部の“エポン（登録商標）”８２５に加えて溶解させ、（ａ）で作製した熱可塑性樹脂粒子を８０質量部混練し、次いで硬化剤として“アラドゥール（登録商標）”９６６４−１を４５質量部混練して熱硬化性樹脂組成物（２）を作製した。 (Ii) 16 parts by weight of PES5003P was added to 60 parts by weight of “Araldite (registered trademark)” MY9655 and 40 parts by weight of “Epon (registered trademark)” 825 in a kneader, and dissolved in (a). 80 parts by mass of the obtained thermoplastic resin particles were kneaded, and then 45 parts by mass of “Aradour (registered trademark)” 9664-1 as a curing agent was kneaded to prepare a thermosetting resin composition (2).
（ｃ）プリプレグの作製
（ｂ）（i）で作製した熱硬化性樹脂組成物（１）をナイフコーターで離型紙に塗布して、３６．５ｇ／ｍ２の樹脂フィルムを２枚作製した。次に、作製したこの２枚の樹脂フィルムを、一方向に配列されたシート状の炭素繊維（“トレカ（登録商標）”Ｔ８００Ｓ−１２Ｋ、東レ（株）製）の両面に積層し、ローラー温度１１０℃、ローラー圧力０．２５ＭＰａで樹脂を含浸させ、予備プリプレグを作製した。さらに（ｂ）（ii）で作製した熱硬化性樹脂組成物（２）をナイフコーターで離型紙に塗布して、２９ｇ／ｍ２の樹脂フィルムを２枚作製して、先ほど作製した予備プリプレグの表面に積層し、ローラー温度１００℃、ローラー圧力０．０７ＭＰａで樹脂を積層し、単位面積質量が２７０ｇ／ｍ２でマトリックス樹脂の質量分率が３４％の一方向炭素繊維強化プリプレグＡを作製した。
(C) Preparation of prepreg (b) The thermosetting resin composition (1) prepared in (i) was applied to release paper with a knife coater to prepare two 36.5 g / m 2 resin films. Next, the produced two resin films are laminated on both sides of a sheet-like carbon fiber ("Treka (registered trademark)" T800S-12K, manufactured by Toray Industries, Inc.) arranged in one direction, and the roller temperature The resin was impregnated at 110 ° C. and a roller pressure of 0.25 MPa to prepare a preliminary prepreg. Further, the thermosetting resin composition (2) prepared in (b) (ii) was applied to a release paper with a knife coater to prepare two 29 g / m 2 resin films, and the preliminary prepreg prepared earlier was used. Laminating on the surface, laminating a resin at a roller temperature of 100 ° C. and a roller pressure of 0.07 MPa, a unidirectional carbon fiber reinforced prepreg A having a unit area mass of 270 g / m 2 and a mass fraction of a matrix resin of 34% was produced. .
（５）一方向炭素繊維強化プリプレグＢの作製方法
次の（ａ）〜（ｃ）の操作により、一方向炭素繊維強化プリプレグＢを作製した。
(5) Production method of unidirectional carbon fiber reinforced prepreg B Unidirectional carbon fiber reinforced prepreg B was produced by the following operations (a) to (c).
（ａ）熱硬化性樹脂組成物の調製
混練機でビスフェノールＡ型エポキシ樹脂（製品名：“ｊＥＲ（登録商標）”８２８、三菱化学(株)製）を４０質量部と、ビスフェノールＡ型エポキシ樹脂（“ｊＥＲ（登録商標）”１００１）を３０質量部と、フェノールノボラック型エポキシ樹脂（“ｊＥＲ（登録商標）”１５４）を３０質量部とを混練させて、次いで硬化剤として、ジシアンジアミド（ＤＩＣＹ７、三菱化学(株)製）を４質量部と、硬化促進剤として、３−（３，４−ジクロロフェニル）１，１−ジメチルウレア（ＤＣＭＵ−９９、保土ヶ谷化学工業(株)製）を３質量部と、粘度調整剤として、ポリビニルホルマール（“ビニレック（登録商標）”Ｋ、チッソ(株)製）を２質量部混練して熱硬化性樹脂組成物を作製した。
(A) Preparation of thermosetting resin composition In a kneader, 40 parts by mass of bisphenol A type epoxy resin (product name: “jER (registered trademark)” 828, manufactured by Mitsubishi Chemical Corporation) and bisphenol A type epoxy resin ("JER (registered trademark)" 1001) and 30 parts by mass of a phenol novolac type epoxy resin ("jER (registered trademark)" 154) were kneaded and then dicyandiamide (DICY7, 4 parts by mass of Mitsubishi Chemical Corporation) and 3 parts by mass of 3- (3,4-dichlorophenyl) 1,1-dimethylurea (DCMU-99, manufactured by Hodogaya Chemical Co., Ltd.) as a curing accelerator As a viscosity modifier, 2 parts by mass of polyvinyl formal (“Vinylec (registered trademark)” K, manufactured by Chisso Corporation) was kneaded to prepare a thermosetting resin composition.
（ｂ）プリプレグの作製
（ａ）で作製した熱硬化性樹脂組成物をナイフコーターで離型紙に塗布して、２６ｇ／ｍ２の樹脂フィルムを２枚作製した。次に、作製したこの２枚の樹脂フィルムを、一方向に配列されたシート状の炭素繊維（“トレカ（登録商標）”Ｔ７００Ｓ−１２Ｋ、東レ(株)製）の両面に積層し、ローラー温度１１０℃、ローラー圧力０．２５ＭＰａで樹脂を含浸させ、単位面積質量が１５２ｇ／ｍ２でマトリックス樹脂の質量分率が３４％の一方向炭素繊維強化プリプレグＢを作製した。
(B) Preparation of prepreg The thermosetting resin composition prepared in (a) was applied to release paper with a knife coater to prepare two 26 g / m 2 resin films. Next, the produced two resin films are laminated on both sides of a sheet-like carbon fiber ("Treka (registered trademark)" T700S-12K, manufactured by Toray Industries, Inc.) arranged in one direction, and the roller temperature The resin was impregnated at 110 ° C. and a roller pressure of 0.25 MPa to prepare a unidirectional carbon fiber reinforced prepreg B having a unit area mass of 152 g / m 2 and a mass fraction of the matrix resin of 34%.
（実施例１）
（４）記載の方法で作製した一方向炭素繊維強化プリプレグＡを用いて、（１）記載の方法でプリプレグ同士の摩擦係数を、（２）記載の方法でプリプレグと型面との摩擦係数を次のようにして測定するとともに、（３）記載の方法で次のようにして繊維強化プラスチックを作製した。
Example 1
(4) Using the unidirectional carbon fiber reinforced prepreg A prepared by the method described in (1), the friction coefficient between the prepregs by the method described in (1), and the friction coefficient between the prepreg and the mold surface by the method described in (2). While measuring as follows, the fiber reinforced plastic was produced by the method of (3) as follows.
（ａ）プリプレグ同士の摩擦係数測定
測定温度を６０℃から１０℃きざみで２００℃まで変更して、測定を行った。結果を表１に示す。
(A) Friction coefficient measurement between prepregs The measurement temperature was changed from 60 ° C to 200 ° C in increments of 10 ° C. The results are shown in Table 1.
（ｂ）プリプレグと型面との摩擦係数測定
測定温度を６０℃から１０℃きざみで２００℃まで変更して、測定を行った。結果を表１に示す。
(B) Measurement of friction coefficient between prepreg and mold surface The measurement temperature was changed from 60 ° C. to 200 ° C. in steps of 10 ° C. and measured. The results are shown in Table 1.
（ｃ）繊維強化プラスチックの成形
賦形温度Ｔ１を１８０℃、成形温度Ｔ２を２００℃とし、２００℃到達後、４６分経過時点で金型から脱型して、繊維強化プラスチックを得た。
(C) Molding of fiber reinforced plastic The molding temperature T1 was 180 ° C., the molding temperature T2 was 200 ° C., and after reaching 200 ° C., the mold was removed from the mold after 46 minutes to obtain a fiber reinforced plastic.
得られた、繊維強化プラスチックの投影面積は、プリプレグ積層体の投影面積よりも大きく、良好な伸張性を発現していた。また、型面と接するプリプレグ層も良好に伸張しており、得られた繊維強化プラスチックの形状に追従していた。なお、積層体からの樹脂の絞り出しは確認されなかった。成形までの所要時間は、積層体の加温時間４分、加圧後の１８０℃から２００℃までの昇温過程で４分、２００℃到達後の硬化時間４６分で、プリプレグ積層体を金型内に設置してから５４分を要した。 The projected area of the obtained fiber reinforced plastic was larger than the projected area of the prepreg laminate, and exhibited good extensibility. Further, the prepreg layer in contact with the mold surface was also well stretched and followed the shape of the obtained fiber reinforced plastic. In addition, squeezing out of the resin from the laminate was not confirmed. The time required for the molding was 4 minutes for the heating time of the laminate, 4 minutes for the heating process from 180 ° C. to 200 ° C. after pressing, and 46 minutes for the curing time after reaching 200 ° C. It took 54 minutes after installation in the mold.
（実施例２）
（５）記載の方法で作製した一方向炭素繊維強化プリプレグＢを用いて、（１）記載の方法でプリプレグ同士の摩擦係数を、（２）記載の方法でプリプレグと型面との摩擦係数を次のようにして測定するとともに、（３）記載の方法で次のようにして繊維強化プラスチックを作製した。
(Example 2)
(5) Using the unidirectional carbon fiber reinforced prepreg B produced by the method described above, the friction coefficient between the prepregs by the method described in (1), and the friction coefficient between the prepreg and the mold surface by the method described in (2). While measuring as follows, the fiber reinforced plastic was produced by the method of (3) as follows.
（ａ）プリプレグの層間摩擦係数測定
測定温度を６０℃から１０℃きざみで１５０℃まで変更して、測定を行った。結果を表２に示す。
(A) Interlayer friction coefficient measurement of prepreg Measurement was performed by changing the measurement temperature from 60 ° C to 150 ° C in increments of 10 ° C. The results are shown in Table 2.
（ｂ）型面とプリプレグの摩擦係数測定
測定温度を６０℃から１０℃きざみで１５０℃まで変更して、測定を行った。結果を表２に示す。
(B) Measurement of coefficient of friction between mold surface and prepreg Measurement was performed by changing the measurement temperature from 60 ° C to 150 ° C in 10 ° C increments. The results are shown in Table 2.
（ｃ）繊維強化プラスチックの成形
賦形温度Ｔ１を１３０℃、成形温度Ｔ２を１５０℃とし、１５０℃到達後、３０分経過時点で金型から脱型して、繊維強化プラスチックを得た。
(C) Molding of Fiber Reinforced Plastic The forming temperature T1 was 130 ° C. and the molding temperature T2 was 150 ° C. After reaching 150 ° C., the mold was removed from the mold after 30 minutes to obtain a fiber reinforced plastic.
得られた、繊維強化プラスチックの投影面積は、プリプレグ積層体の投影面積よりも大きく、良好な伸張性を発現していた。また、型面と接するプリプレグ層も良好に伸張しており、得られた繊維強化プラスチックの形状に追従していた。なお、積層体からの樹脂の絞り出しは確認されなかった。成形までの所要時間は、積層体の加温時間４分、加圧後の１３０℃から１５０℃までの昇温過程で４分、１５０℃到達後の硬化時間３０分で、プリプレグ積層体を金型内に設置してから３８分を要した。 The projected area of the obtained fiber reinforced plastic was larger than the projected area of the prepreg laminate, and exhibited good extensibility. Further, the prepreg layer in contact with the mold surface was also well stretched and followed the shape of the obtained fiber reinforced plastic. In addition, squeezing out of the resin from the laminate was not confirmed. The time required for molding is 4 minutes for the heating time of the laminate, 4 minutes for the temperature increase process from 130 ° C. to 150 ° C. after pressing, and 30 minutes for the curing time after reaching 150 ° C. It took 38 minutes after installation in the mold.
（比較例１）
（４）記載の方法で作製した一方向炭素繊維強化プリプレグＡを用いて、（３）記載の方法で繊維強化プラスチックを作製した。上記、繊維強化プラスチックの成形において、賦形温度Ｔ１および成形温度Ｔ２を１８０℃として、実施した。得られた、繊維強化プラスチックの投影面積は、プリプレグ積層体の投影面積よりも大きく、良好な伸張性を発現していた。また、型面と接するプリプレグ層も良好に伸張しており、得られた繊維強化プラスチックの形状に追従していた。なお、積層体からの樹脂の絞り出しは確認されなかった。しかしながら、実施例１に記載の繊維強化プラスチック同等の硬化度を得るため、加圧後、９７分間成形温度を保持する必要があり、成形までの所要時間は、積層体の加温時間４分、硬化時間９７分で、プリプレグ積層体を金型内に設置してから１０１分を要した。
(Comparative Example 1)
Using the unidirectional carbon fiber reinforced prepreg A produced by the method described in (4), a fiber reinforced plastic was produced by the method described in (3). In the above-described fiber reinforced plastic molding, the shaping temperature T1 and the molding temperature T2 were set to 180 ° C. The projected area of the obtained fiber reinforced plastic was larger than the projected area of the prepreg laminate, and exhibited good extensibility. Further, the prepreg layer in contact with the mold surface was also well stretched and followed the shape of the obtained fiber reinforced plastic. In addition, squeezing out of the resin from the laminate was not confirmed. However, in order to obtain a degree of curing equivalent to the fiber-reinforced plastic described in Example 1, it is necessary to maintain the molding temperature for 97 minutes after pressing, and the time required for molding is 4 minutes for the heating time of the laminate, The curing time was 97 minutes, and 101 minutes were required after the prepreg laminate was placed in the mold.
（比較例２）
（４）記載の方法で作製した一方向炭素繊維強化プリプレグＡを用いて、（３）記載の方法で繊維強化プラスチックを作製した。上記、繊維強化プラスチックの成形において、賦形温度Ｔ１および成形温度Ｔ２を２００℃として、実施した。得られた、繊維強化プラスチックの投影面積は、プリプレグ積層体の投影面積よりも大きく、伸張性を発現していた。一方、型面と接するプリプレグ層は、得られた繊維強化プラスチックの形状に追従せず、加圧前の形状で硬化していた。なお、積層体からの樹脂の絞り出しは確認されなかった。成形までの所要時間は、積層体の加温時間４分、硬化時間４７分で、プリプレグ積層体を金型内に設置してから５１分を要した。
(Comparative Example 2)
Using the unidirectional carbon fiber reinforced prepreg A produced by the method described in (4), a fiber reinforced plastic was produced by the method described in (3). In the above-described fiber reinforced plastic molding, the shaping temperature T1 and the molding temperature T2 were set to 200 ° C. The projected area of the obtained fiber reinforced plastic was larger than the projected area of the prepreg laminate, and exhibited extensibility. On the other hand, the prepreg layer in contact with the mold surface did not follow the shape of the obtained fiber-reinforced plastic and was cured in the shape before pressing. In addition, squeezing out of the resin from the laminate was not confirmed. The time required for molding was 4 minutes for heating the laminate and 47 minutes for curing, and 51 minutes were required after the prepreg laminate was placed in the mold.
（比較例３）
（４）記載の方法で作製した一方向炭素繊維強化プリプレグＡを用いて、（３）記載の方法で繊維強化プラスチックを作製した。上記、繊維強化プラスチックの成形において、賦形温度Ｔ１を最低粘度付近である１２０℃、成形温度Ｔ２を２００℃とし、２００℃到達後、４５分経過時点で金型から脱型して、繊維強化プラスチックを得た。
(Comparative Example 3)
Using the unidirectional carbon fiber reinforced prepreg A produced by the method described in (4), a fiber reinforced plastic was produced by the method described in (3). In the above-mentioned fiber reinforced plastic molding, the forming temperature T1 is set to 120 ° C. near the minimum viscosity, the molding temperature T2 is set to 200 ° C., and after reaching 200 ° C., the mold is removed from the mold when 45 minutes have elapsed, thereby reinforcing the fiber. Got plastic.
得られた、繊維強化プラスチックの投影面積は、プリプレグ積層体の投影面積よりも大きく、伸張性を発現していた。また、型面と接するプリプレグ層も、得られた繊維強化プラスチックの形状に追従していた。一方で、積層体からの樹脂の絞り出しが確認された。成形までの所要時間は、積層体の加温時間４分、加圧後の１２０℃から２００℃までの昇温過程で１６分、２００℃到達後の硬化時間４５分で、プリプレグ積層体を金型内に設置してから６５分を要した。賦形温度Ｔ１が低いため、成形温度Ｔ２までの昇温に時間を要し、成形時間が長くなってしまった。 The projected area of the obtained fiber reinforced plastic was larger than the projected area of the prepreg laminate, and exhibited extensibility. Further, the prepreg layer in contact with the mold surface also followed the shape of the obtained fiber reinforced plastic. On the other hand, squeezing out of the resin from the laminate was confirmed. The time required for molding is 4 minutes for the heating time of the laminate, 16 minutes for the heating process from 120 ° C. to 200 ° C. after pressing, and 45 minutes for the curing time after reaching 200 ° C., and the prepreg laminate is made of gold. It took 65 minutes after installation in the mold. Since the shaping temperature T1 is low, it takes time to raise the temperature to the molding temperature T2, and the molding time becomes long.
（比較例４）
（５）記載の方法で作製した一方向炭素繊維強化プリプレグＢを用いて、（３）記載の方法で繊維強化プラスチックを作製した。上記、繊維強化プラスチックの成形において、賦形温度Ｔ１および成形温度Ｔ２を１５０℃として、実施した。得られた、繊維強化プラスチックの投影面積は、プリプレグ積層体の投影面積よりも大きく、良好な伸張性を発現していた。一方、型面と接するプリプレグ層は、得られた繊維強化プラスチックの形状に追従せず、加圧前の形状で硬化していた。なお、積層体からの樹脂の絞り出しは確認されなかった。成形までの所要時間は、積層体の加温時間４分、硬化時間３３分で、プリプレグ積層体を金型内に設置してから３７分を要した。
(Comparative Example 4)
Using the unidirectional carbon fiber reinforced prepreg B produced by the method described in (5), a fiber reinforced plastic was produced by the method described in (3). In the above-described fiber reinforced plastic molding, the shaping temperature T1 and the molding temperature T2 were set to 150 ° C. The projected area of the obtained fiber reinforced plastic was larger than the projected area of the prepreg laminate, and exhibited good extensibility. On the other hand, the prepreg layer in contact with the mold surface did not follow the shape of the obtained fiber-reinforced plastic and was cured in the shape before pressing. In addition, squeezing out of the resin from the laminate was not confirmed. The time required for molding was 4 minutes for the heating time of the laminate, and 33 minutes for the curing time. It took 37 minutes after the prepreg laminate was placed in the mold.
（比較例５）
（５）記載の方法で作製した一方向炭素繊維強化プリプレグＢを用いて、（３）記載の方法で繊維強化プラスチックを作製した。上記、繊維強化プラスチックの成形において、賦形温度Ｔ１および成形温度Ｔ２を１３０℃として、実施した。得られた、繊維強化プラスチックの投影面積は、プリプレグ積層体の投影面積よりも大きく、良好な伸張性を発現していた。また、型面と接するプリプレグ層も良好に伸張し、得られた繊維強化プラスチックの形状に追従していた。なお、積層体からの樹脂の絞り出しは確認されなかった。しかしながら、実施例２に記載の繊維強化プラスチック同等の硬化度を得るため、加圧後、７１分間成形温度を保持する必要があり、成形までの所要時間は、積層体の加温時間４分、硬化時間７１分で、プリプレグ積層体を金型内に設置してから７５分を要した。
(Comparative Example 5)
Using the unidirectional carbon fiber reinforced prepreg B produced by the method described in (5), a fiber reinforced plastic was produced by the method described in (3). In the above-described fiber reinforced plastic molding, the shaping temperature T1 and the molding temperature T2 were set to 130 ° C. The projected area of the obtained fiber reinforced plastic was larger than the projected area of the prepreg laminate, and exhibited good extensibility. Further, the prepreg layer in contact with the mold surface also stretched well and followed the shape of the obtained fiber reinforced plastic. In addition, squeezing out of the resin from the laminate was not confirmed. However, in order to obtain a degree of curing equivalent to the fiber-reinforced plastic described in Example 2, it is necessary to maintain the molding temperature for 71 minutes after pressing, and the time required for molding is 4 minutes for the heating time of the laminate, The curing time was 71 minutes, and 75 minutes were required after the prepreg laminate was placed in the mold.
（比較例６）
（５）記載の方法で作製した一方向炭素繊維強化プリプレグＢを用いて、（３）記載の方法で繊維強化プラスチックを作製した。上記、繊維強化プラスチックの成形において、賦形温度Ｔ１を最低粘度付近である１１０℃、成形温度Ｔ２を１５０℃とし、１５０℃到達後、３２分経過時点で金型から脱型して、繊維強化プラスチックを得た。
(Comparative Example 6)
Using the unidirectional carbon fiber reinforced prepreg B produced by the method described in (5), a fiber reinforced plastic was produced by the method described in (3). In the above-mentioned molding of fiber reinforced plastic, the forming temperature T1 is set to 110 ° C. which is near the minimum viscosity, the molding temperature T2 is set to 150 ° C., and after reaching 150 ° C., the mold is removed from the mold when 32 minutes have passed, thereby reinforcing the fiber Got plastic.
得られた、繊維強化プラスチックの投影面積は、プリプレグ積層体の投影面積よりも大きく、伸張性を発現していた。また、型面と接するプリプレグ層も良好に伸張しており、得られた繊維強化プラスチックの形状に追従していた。一方で、積層体からの樹脂の絞り出しが確認された。成形までの所要時間は、積層体の加温時間４分、加圧後の１１０℃から１５０℃までの昇温過程で８分、１５０℃到達後の硬化時間３４分で、プリプレグ積層体を金型内に設置してから４６分を要した。賦形温度Ｔ１が低いため、成形温度Ｔ２までの昇温に時間を要し、成形時間が長くなってしまった。 The projected area of the obtained fiber reinforced plastic was larger than the projected area of the prepreg laminate, and exhibited extensibility. Further, the prepreg layer in contact with the mold surface was also well stretched and followed the shape of the obtained fiber reinforced plastic. On the other hand, squeezing out of the resin from the laminate was confirmed. The time required for molding is 4 minutes for the heating time of the laminate, 8 minutes in the temperature raising process from 110 ° C. to 150 ° C. after pressurization, and 34 minutes for the curing time after reaching 150 ° C. It took 46 minutes after installation in the mold. Since the shaping temperature T1 is low, it takes time to raise the temperature to the molding temperature T2, and the molding time becomes long.
１：圧板
２：離型紙
３：中央層
４：部材
５：スペーサー
６：切込プリプレグ
７：繊維方向
８：繊維直交方向
９：断続的な切込
１０：連続的な切込
１１：断続的な斜め切込（繊維方向に対して正の角度）
１２：断続的な斜め切込（繊維方向に対して負の角度）
１３：断続的な切込の列
１４：金型（上）
１５：金型（下）
１６：プリプレグ積層体
１７：金型キャビティ領域
１８：積層体伸張方向
1: pressure plate 2: release paper 3: center layer 4: member 5: spacer 6: cutting prepreg 7: fiber direction 8: fiber orthogonal direction 9: intermittent cutting 10: continuous cutting 11: intermittent Diagonal cut (positive angle with respect to fiber direction)
12: Intermittent diagonal cut (negative angle with respect to fiber direction)
13: Row of intermittent cuts 14: Mold (top)
15: Mold (bottom)
16: Pre-preg laminate 17: Mold cavity region 18: Laminate extension direction
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Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| WO2017110991A1 (en) * | 2015-12-25 | 2017-06-29 | 東レ株式会社 | Prepreg and method for manufacturing same |
| WO2018117181A1 (en) * | 2016-12-22 | 2018-06-28 | 東レ株式会社 | Composite structure and method for manufacturing same |
| JP2018123267A (en) * | 2017-02-03 | 2018-08-09 | 三菱ケミカル株式会社 | Fiber-reinforced plastic |
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Cited By (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| WO2017110991A1 (en) * | 2015-12-25 | 2017-06-29 | 東レ株式会社 | Prepreg and method for manufacturing same |
| US10723087B2 (en) | 2015-12-25 | 2020-07-28 | Toray Industries, Inc. | Prepreg and method for manufacturing same |
| WO2018117181A1 (en) * | 2016-12-22 | 2018-06-28 | 東レ株式会社 | Composite structure and method for manufacturing same |
| JPWO2018117181A1 (en) * | 2016-12-22 | 2018-12-20 | 東レ株式会社 | Composite structure and manufacturing method thereof |
| US10994510B2 (en) | 2016-12-22 | 2021-05-04 | Toray Industries, Inc. | Composite structure and method for manufacturing same |
| JP2018123267A (en) * | 2017-02-03 | 2018-08-09 | 三菱ケミカル株式会社 | Fiber-reinforced plastic |
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