JP2004160927A - Preform substrate, preform, fiber-reinforced plastic molding and molding method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a preform substrate permitting low-cost manufacture of large and thick fiber-reinforced plastic moldings and having excellent reliability and mechanical characteristics as a molding, including excellent tensile strength, tensile elastic modulus, compression strength, compression elastic modulus and impact fracture toughness, a preform, a method of molding a fiber-reinforced plastic, and a fiber-reinforced plastic molding. <P>SOLUTION: The substrate is composed of a unidirectional fabric base material in which reinforcing fiber threads are oriented in parallel in the longitudinal direction and particles are adhered to at least one side of the fabric. The material is laminated into a large number of intersected layers and integrated into a preform by an integrating means. <P>COPYRIGHT: (C)2004,JPO

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a preform base material suitable for fiber-reinforced plastics, a preform and a fiber-reinforced plastic molded article, and a method for molding the same.
[0002]
[Prior art]
In order to improve the fuel efficiency of the aircraft and increase the payload, it is necessary to reduce the weight of the fuselage. Not only secondary structures such as spoilers, ailerons, wing fuselage fairings and elevators, but also the horizontal and vertical stabilizers of the tail wing recently In addition, fiber reinforced plastics, especially carbon fiber reinforced plastics, have been put to practical use for the primary structure of the floor support girder. Further, in recent years, attempts have been made to replace conventional duralumin with carbon fiber reinforced plastic for primary large-sized structures such as skins of main wings and stringers in order to reduce the weight and cost of the fuselage.
[0003]
As primary structural materials for aircraft, mechanical properties such as tensile strength, tensile modulus, compressive strength, compressive modulus and impact fracture toughness of carbon fiber reinforced plastics are required, and at the same time, to achieve low cost. Requires a molding method capable of achieving cost reduction and a reinforcing fiber material adapted to this molding method.
[0004]
As a low cost molding method, a vacuum bag molding method has recently attracted attention as compared with a conventional autoclave molding method in which a laminate of prepregs is bagged, and the laminate is heated and pressurized in an autoclave while maintaining the laminate under vacuum. In this method, a reinforcing fiber material to which a matrix resin is not adhered is laminated, a resin diffusion medium is placed on the laminate, these are bagged with a film, and the resin is passed through the diffusion medium through the diffusion medium while keeping the inside vacuum. And flows in the thickness direction of the laminate, which seems to be suitable as a method for molding a molded article having a large area.
[0005]
However, when a reinforcing fiber material such as a woven fabric is simply laminated, when molded into a fiber-reinforced plastic, the fracture toughness between layers cannot be ensured. In other words, the fiber-reinforced plastic made of continuous carbon fibers has excellent mechanical properties in the fiber axis direction, but the mechanical properties rapidly decrease as the distance from the fiber axis increases. As a countermeasure, for example, the fiber axis direction such that the mechanical properties become a quasi-isotropic base material is the length (0 °) direction, the width (90 °) direction, or the oblique (± 45 °) direction of the FRP (fiber reinforced plastic) molded product.゜) Laminated and molded in the direction. However, when an impact in the direction perpendicular to the plane is applied to such a formed plate, for example, the mechanical properties in the plane direction of the 0 ° layer and the 45 ° layer are extremely different, so the deformation of the 0 ° layer and the 45 ° layer is different, A large crack may be generated between the layers, and the compressive strength of the formed plate is greatly reduced. The primary structure of an aircraft is required to have high reliability, and at present, structural members made of duralumin are inspected for damage and cracks by periodic visual observation. Unfortunately, however, carbon fiber reinforced plastic is black and opaque, so it is not possible to visually observe the occurrence of cracks caused by rocks flying during takeoff and landing, tools falling during assembly or repair, collisions during assembly transportation, etc. , The damage state cannot be detected.
[0006]
In addition, the vacuum impregnation molding method is suitable as a molding method of a main wing skin material of an aircraft having a large area, but since the skin material is thick as 20 mm to 30 mm, the number of layers of woven fabrics and the like increases to 80 to 200, The resin does not flow to the surface of the laminate opposite to the diffusion medium, which causes a defect of poor resin impregnation.
[0007]
Further, in order to improve the resin impregnation property, if the woven material is a two-way woven fabric in which the reinforcing fiber yarns are arranged in two directions of the warp direction and the weft direction, and the resin can be impregnated from the empty space, The resin can be impregnated even with a thick fiber reinforced plastic by the vacuum impregnation molding method. However, in such a woven fabric, the reinforcing fiber yarn extending in the warp direction by a thick weft is largely crimped (bent), and when it is formed, stress is concentrated on the crimp portion, and the tensile strength and the compressive strength are reduced, and the primary strength is reduced. The predetermined strength as a structural material is not exhibited, and the design strength is reduced. Therefore, there has been a problem that the structural material needs to be designed to be thick, and it is not possible to achieve weight reduction.
[0008]
In addition, a large-sized structural material such as a main wing skin material has a large width of, for example, 5 to 7 m and a length of 20 to 30 m. In the length direction, a large number of woven fabrics with a width of about 100 cm are stacked in multiple directions such as 0 °, + α ° (usually + 45 °), -α ° (usually -45 °), and 90 °. It requires a lot of man-hours to laminate the reinforcing fiber material, despite the labor-saving molding method of vacuum bag molding and the lamination of reinforcing fiber materials such as long woven fabrics. Therefore, the fiber material, that is, the reinforcing fiber yarn is bent, and it is difficult to laminate the fiber straight.
[0009]
On the other hand, as a multiaxial fabric, Patent Document 1 discloses a multiaxial fabric in which a reinforcing fiber yarn is expanded, and a tape in which this state is fixed by a binder or the like is laminated in multiple directions in layers and integrated with stitch yarn. Although disclosed, such a fabric does not have a gap for resin impregnation, and thus there is a problem that sufficient impregnation cannot be ensured even when a thick fiber reinforced plastic is molded by a vacuum bag molding method. Was.
[0010]
Also, a multiaxial fabric is known in which reinforcing fiber yarns arranged in parallel are laminated in a sheet shape in multiple directions, and this is stitched and integrated with a stitch thread, but when reinforcing fiber yarns are arranged in a sheet shape in parallel. , Each thread hooked on a pin is free until it is fixed in position by stitch thread, it is difficult to arrange all threads accurately and there is a problem that a gap is formed between the threads. . Further, this state becomes more remarkable because the width of the free state becomes larger as the width of the multiaxial fabric increases, and the mechanical properties of the fiber-reinforced plastic deteriorate, so that the reliability is lacking. was there.
[0011]
[Patent Document 1]
JP-T-2001-516406 (Claims)
[0012]
[Problems to be solved by the invention]
In view of the background of the prior art, the object of the present invention is to provide a large, thick fiber-reinforced plastic molded product that is inexpensive, can be manufactured with high productivity, and has excellent reliability. An object of the present invention is to provide a preform substrate, a preform, a method of molding fiber-reinforced plastic, and a fiber-reinforced plastic molded article having excellent mechanical properties such as compression strength, compression modulus and impact fracture toughness.
[0013]
[Means for Solving the Problems]
In order to solve the above problems, the present invention employs the following means. That is, the preform substrate according to the present invention comprises a unidirectional woven substrate in which reinforcing fiber yarns are arranged in parallel in the length direction and particles are adhered to at least one surface, and the unidirectional woven substrate is Are cross-laminated and integrated by an integrating means.
[0014]
In this preform base material, the gap between the reinforcing fiber yarns adjacent to the one-way woven fabric base material is preferably a substantially uniform gap of more than 0.1 mm and less than 1.0 mm in the entire width of the woven fabric.
[0015]
Further, the unidirectional woven fabric has reinforcing fiber yarns on both sides of a sheet surface of a yarn group formed by aligning reinforcing fiber yarns having no bending such that stress is concentrated in a direction parallel to each other and in a sheet shape. A one-way non-crimp fabric in which intersecting weft direction auxiliary yarn groups are located, and the weft direction auxiliary yarn groups and the warp direction auxiliary yarn groups parallel to the reinforcing fiber yarns form a woven structure and integrally hold the yarn groups. It is preferable that
[0016]
Further, it is preferable that the integration means is a stitch.
[0017]
It is preferable that the cross lamination angle includes at least 0 ° layer with respect to the length direction of the preform base material.
[0018]
Further, it is preferable that the cross lamination angle includes at least two directions of a + α ゜ layer and a −α ゜ layer with respect to the length direction of the preform base material.
[0019]
Further, it is also possible to adopt a configuration in which the number of laminations is not uniform in the length direction of the preform base material, but increases or decreases in the middle.
[0020]
As the reinforcing fiber yarn, it is preferable to use carbon fiber, but it is not limited to this. When carbon fibers are used, the number of filaments of the carbon fibers is more than 12,000 and less than 25,000, the tensile modulus of the carbon fibers is more than 280 GPa and less than 500 GPa, and the breaking strain energy is 53 MJ / m ³ The above carbon fibers are preferable.
[0021]
In a preferred embodiment, the warp yarn is a carbon fiber yarn, the fineness of the weft direction auxiliary yarn is more than 6 dtex and less than 70 decitex, and the density of the weft direction auxiliary yarn is 0.3 / cm. And less than 6.0 fibers / cm, and the basis weight of the carbon fibers is 100 g / m. ² Over 350g / m ² There may be mentioned configurations that are less than. Among them, the fineness of the weft direction auxiliary yarn is more than 15 decitex and less than 50 decitex, the density of the weft direction auxiliary yarn is more than 1.0 yarn / cm and less than 4.0 yarn / cm, and the basis weight of the carbon fiber is less. 180 g / m ² Over 210 g / m ² It is preferably less than.
[0022]
The particles preferably have a function of imparting interlayer toughness of the fiber reinforced plastic and have a melting point or a glass transition temperature of more than 50 ° C and less than 150 ° C.
[0023]
In addition, the amount of particles attached is preferably more than 2% and less than 20% based on the weight of the reinforcing fibers constituting the one-way woven fabric substrate.
[0024]
The present invention also provides a laminate wherein a plurality of the preform substrates as described above are laminated, and each of the preform substrates is continuously laminated over the entire surface of the laminate.
[0025]
Further, the preform according to the present invention is characterized in that a plurality of the preform substrates as described above are laminated, and the woven substrate and / or the preform substrate are adhered to each other.
[0026]
In this preform, it is preferable that the preform substrate is laminated without interruption over the entire surface of the preform.
[0027]
Further, it is preferable that the reinforcing fiber volume ratio Vpf in the preform is more than 45% and less than 60%.
[0028]
In addition, it is preferable that a gap between the reinforcing fiber yarns adjacent to the one-way woven fabric base constituting the preform is more than 0.1 mm and less than 1.0 mm.
[0029]
In the method of molding a fiber-reinforced plastic according to the present invention, a predetermined number of the above-described preform substrates are laminated on a molding die, or a laminate of the above-described preform substrates is arranged in a molding die, and the resin is placed on the laminate. After placing the medium that diffuses in the direction, cover the whole with the bag film, then put the inside covered with the bag film under reduced pressure, and diffuse the liquid thermosetting resin on one side of the laminated preform base material. And a method of impregnating the preform base material with a resin and curing the resin.
[0030]
Further, in the method of molding a fiber-reinforced plastic according to the present invention, the above-described preform is laminated on a mold, a medium for diffusing the resin in the surface direction is placed on the preform, and the whole is covered with a bag film. The method is characterized in that the inside covered with the film is decompressed, a liquid thermosetting resin is diffused on one side of the laminated preform, and the preform is impregnated with the resin and cured.
[0031]
In such a method of molding a fiber-reinforced plastic according to the present invention, the thermosetting resin is an epoxy resin, and the resin and the mold and the preform base material or the preform are heated to lower the resin viscosity and to impregnate the resin. Is preferably improved.
[0032]
The fiber-reinforced plastic molded article according to the present invention is obtained by the molding method described above.
[0033]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, preferred embodiments of the present invention will be described with reference to the drawings.
FIG. 1 is a schematic perspective view of a unidirectional woven fabric substrate 1 constituting a preform substrate according to one embodiment of the present invention. In FIG. 1, a unidirectional woven fabric substrate 1 has reinforcing fiber yarns 2 arranged in the warp direction, and one thin weft yarn 3 as a lateral auxiliary yarn alternately intersects with the warp yarns to form adjacent reinforcing yarns. The fibers A have a flat structure with a gap A formed between the fiber yarns. Particles 4 adhere to the surface of the unidirectional woven fabric, and a gap A is formed between adjacent reinforcing fiber yarns.
[0034]
FIG. 2 is a schematic perspective view showing another embodiment of the unidirectional woven fabric substrate 1. In FIG. 2, a unidirectional woven fabric substrate 1 has reinforcing fiber yarns 2 having no bend such that stress is concentrated and arranged in a sheet parallel to each other in one direction, and reinforcing fiber yarns are arranged on both sides of the sheet surface. A thin weft yarn 3 intersecting with the weft yarn 3 and the warp direction auxiliary yarn 5 in parallel with the reinforcing fiber yarn form a woven structure to integrally hold the reinforcing fiber yarn. Particles 4 adhere to the surface of the one-way non-crimp fabric, and a gap A is formed between adjacent reinforcing fiber yarns.
[0035]
In FIGS. 1 and 2, the case where the reinforcing fiber yarn of the warp and the weft are integrated in a flat structure and a non-crimp structure as the unidirectional fabric forming the unidirectional fabric base material is described. There may be.
[0036]
The reinforcing fiber yarn used in the present invention is a multifilament yarn, and the type thereof is not particularly limited, and examples thereof include glass fiber, organic (polyaramid, PBO, PVA, PE, etc.) fiber or carbon fiber. . Particularly, carbon fibers are excellent in specific strength and specific elastic modulus and excellent in water absorption resistance, and therefore are preferably used as reinforcing fiber yarns for aircraft structural materials and automobiles.
[0037]
Above all, if the carbon fiber is a high-toughness fiber, the impact-absorbing energy of the fiber-reinforced plastic to be molded becomes large, so that it can be applied as a primary structural material of an aircraft. That is, the tensile modulus of elasticity (E) measured according to JIS-R-7601 exceeds 280 GPa and is less than 500 GPa, and the fracture strain energy (σ ² / 2E, σ: tensile strength measured according to JIS-R-7601) of 53 MJ / m ³ It is preferable that it is above.
[0038]
When carbon fiber is used as the reinforcing fiber yarn, the number of filaments is preferably more than 12,000 and less than 25,000, and the yarn fineness is preferably more than 800 tex and less than 1,800 tex. Within such a range, there is an advantage that the form of the unidirectional fabric is stable, an appropriate gap is easily formed between adjacent yarns, and high-performance carbon fibers can be obtained relatively inexpensively.
[0039]
In addition, the reinforcing fiber yarn in the present invention is preferably substantially non-twisted from the viewpoint of a high reinforcing fiber volume ratio of the molded composite material and an expression rate of mechanical properties.
[0040]
The weft used in the present invention is nylon 6 fiber, nylon 66 fiber, nylon 11 fiber, nylon 12 fiber, polyester fiber, polyaramid fiber, polyphenylene sulfide fiber, polyetherimide fiber, polyether sulfone fiber, polyketone fiber, polyether ketone. The weft is preferably a weft containing at least one selected from fibers, polyetheretherketone fibers and glass fibers. Among them, nylon 66 is preferable because it has good adhesion to a resin, and a fine fiber can be obtained by stretching.
[0041]
Further, the weft of the unidirectional woven fabric substrate in the present invention is preferably a multifilament yarn. With a multifilament yarn, the fineness (diameter) of a single filament yarn can be reduced. When this is used in a substantially untwisted state, the weft in the woven fabric is in a form in which the single filaments are arranged in parallel without overlapping in the thickness direction, and the thickness of the weft is reduced, Crimp due to the crossing or crossing of the reinforcing fiber yarn and the weft yarn is reduced, and the straightness of the reinforcing fiber yarn is increased in the fiber reinforced plastic, resulting in high mechanical properties.
[0042]
From the same viewpoint, the thickness of the weft yarn is preferably as thin as possible, and the fineness of the weft yarn is preferably more than 6 dtex and less than 70 dtex. More preferably, it is more than 15 dtex and less than 50 dtex. Originally, in the present invention, the major role of the weft yarn is to form a gap between adjacent reinforcing fiber yarns and to maintain the shape of the woven fabric substrate. If the weft is thick, the reinforcing fiber yarns are crimped in the fiber reinforced plastic, and the straightness of the yarns is reduced, which is not preferable.
[0043]
Further, the density of the weft yarn is preferably more than 0.3 yarns / cm and less than 6.0 yarns / cm, more preferably more than 2.0 yarns / cm and less than 4.0 yarns / cm. If the density of the weft yarn is low, the fabric will come into contact with rolls or guide bars during weaving or in the powder dispersing process, causing the weft yarn to be disturbed, and adjacent reinforcement that will become a resin flow path during vacuum bag molding. It is not preferable because the gap between the fiber yarns becomes small and the impregnating property of the resin becomes poor. In addition, when the density of the weft yarn increases, the crimp of the reinforcing fiber yarn of the warp yarn increases, and the amount of the weft yarn fiber increases, and the heat resistance of the fiber reinforced plastic decreases due to moisture absorption.
[0044]
In addition, in order to improve the adhesion between the weft yarn and the resin used in the present invention, the process oil agent attached when the fiber is spun is removed by a scouring treatment or the like. Preferably, the dry heat shrinkage at 200 ° C. is set to 4% or less by heat treatment.
[0045]
The warp auxiliary yarns in the non-crimp fabric of FIG. 2 prevent the reinforcing fiber yarns arranged in the warp direction from spreading by intersecting the warp auxiliary yarns and the weft yarns, so that the space between adjacent reinforcing fiber yarns is reduced. To secure the resin flow path during vacuum bag molding. In addition, in order to eliminate crimps caused by the crossing of the weft and the reinforcing fiber yarn, the weft yarn is crossed on both sides of the reinforcing fiber yarn, and the warp auxiliary yarn and the weft yarn are crossed to arrange the reinforcing fiber yarns straight. It is to try to make it.
[0046]
As the auxiliary yarn, a glass fiber yarn that does not shrink due to adhesion of particles or heating during molding is preferable. Further, since the auxiliary yarn has substantially no reinforcing effect on the fiber-reinforced plastic, it is not necessary to make it so thick, and the fineness is preferably more than 100 dtex and less than 470 dtex. In addition, covering is performed on the auxiliary yarn in order to secure the resin flow path, and the resin flow path can be secured by twisting the covering yarn. The yarn used for the covering is nylon 6 fiber, nylon 66 fiber, nylon 11 fiber, nylon 12 fiber, polyester fiber, polyaramid fiber, polyphenylene sulfide fiber, polyetherimide fiber, polyether sulfone fiber, polyketone fiber, polyether ketone fiber. Fiber, polyetheretherketone fiber, especially nylon 66, has good adhesion to resin, and the fineness is more than 15 dtex and less than 50 dtex.
[0047]
The gap A between adjacent reinforcing fiber yarns of the textile substrate in the preform substrate is important for securing the flow path of the resin in the preform substrate and the preform, and is adjacent to each other in the entire width of the textile substrate. The average spacing of the reinforcing fiber yarns is preferably in the range of 0.1 to 1 mm. It is more preferably in the range of 0.2 to 0.8 mm, and still more preferably in the range of 0.3 to 0.5 mm. Within such a range, the above-described effect of forming an intra-layer flow path will be sufficiently exhibited. Below that, it may not be sufficiently expressed. Conversely, if the width is too large, a large resin-rich portion will be formed during molding, which may lead to a decrease in the volume fraction of reinforcing fibers, a decrease in mechanical properties (particularly, fatigue strength), the occurrence of thermal cracks, and the like. In the measurement of the spacing between the reinforcing fiber yarns, even if auxiliary yarns exist between the reinforcing fiber yarns as in a non-crimp fabric, since the auxiliary yarns are thin, they do not significantly affect the flow of the resin, and are ignored. Measured.
[0048]
In addition, the gap A between adjacent reinforcing fiber yarns of the woven fabric substrate in the above was measured using a measuring microscope capable of measuring with an accuracy of 0.01 mm at 100 gaps, and the average value was defined as the gap value. . If measurement is not possible with a measuring microscope, measurement can also be performed with a stereoscopic microscope.
[0049]
The preferred range of the basis weight of the carbon fiber of the textile substrate used in the present invention is 180 g / m2. ² Over 350g / m ² Less than 180 g / m ² Over 210 g / m ² Is less than.
[0050]
If the basis weight of the carbon fiber is too small, when obtaining a molded body having a predetermined thickness, the required amount of fabric is increased, the fabric manufacturing cost and the particle bonding cost are increased, and the number of laminated layers is increased, so that cost reduction is achieved. I can not connect it. Also, when the basis weight is increased, the gap between the yarns is reduced, and the thickness of the molded body is changed. It is not preferable because stress concentration may act on the cut portion of the strip.
[0051]
The particles adhere to the woven fabric on the woven fabric substrate used in the present invention, and the amount of the particles is preferably more than 2% and less than 20% based on the weight of the reinforcing fibers. When the particles are adhered in the above range, the particles adhere to the reinforcing fiber yarns and the weft yarns in the woven fabric and the auxiliary yarns in the non-crimp woven fabric, thereby preventing misalignment of the woven fabric and stabilizing the form. Further, the adhesiveness between the woven fabrics is obtained when the woven fabric substrates are laminated to obtain a preform base material or a preform.
[0052]
In addition, the particles in the above-mentioned range serve as crack stoppers in a fiber-reinforced plastic obtained by laminating a woven fabric substrate. In particular, when the fiber-reinforced plastic is subjected to an impact, it plays a role in suppressing damage between layers of the woven fabric, that is, in suppressing the progress of cracks, and the decrease in compressive strength after impact is reduced.
[0053]
If the particle amount is less than 2%, a sufficient crack stopper effect between the layers cannot be obtained. On the other hand, if the amount of particles exceeds 20%, the volume ratio of reinforcing fibers in the case of fiber-reinforced plastic becomes too small, so that not only the mechanical properties are lowered, but also the heating, pressurizing and preforming when bonding the particles. When heating and pressurizing in the high fiber density treatment, the particles are deformed, filling gaps between the yarns, crushing the flow path of the matrix resin, and impeding impregnation, which is not preferable.
[0054]
Such particles may adhere to the surface of the textile substrate and adhere to one side or both sides of the textile substrate. In the case of producing a textile substrate at lower cost, the former is preferred.
[0055]
The smaller the average diameter of the particles (or the average minor axis in the case of an elliptical shape), the more uniformly the particles can be dispersed on the surface of the woven fabric, so the diameter is preferably 1 mm or less, more preferably 250 μm or less, and more preferably 50 μm or less. The following are more preferred.
[0056]
If the vertical irregularities on the surface of the woven fabric of the particles adhered to the woven fabric substrate are too large, the reinforcing fiber yarn located in contact with the woven fabric may be bent, so the average thickness of the particles on the woven fabric surface Is preferably in the range of 5 to 250 μm. More preferably, it is in the range of 10 to 100 μm, even more preferably in the range of 15 to 60 μm.
[0057]
The particles used in the present invention are subjected to a heat treatment in order to adhere the particles to the fabric and to perform a high fiber density treatment of the preform. However, from the viewpoint of workability, the particles have a melting point or glass transition temperature in the range of 50 to 150 ° C. Are preferred. The temperature is more preferably in the range of 70 to 140C, and still more preferably in the range of 90 to 120C.
[0058]
The melting point and the glass transition point referred to here indicate the melting temperature of the crystal and the transition temperature to the glass state measured by a differential scanning calorimeter (DSC), respectively.
[0059]
The component of the particles is not particularly limited as long as it improves the handleability of the woven fabric substrate and improves the mechanical properties of the fiber-reinforced plastic obtained using the same. Various thermosetting resins and / or thermoplastic resins can be used as the particles.
[0060]
When using a thermoplastic resin as the main component of the particles, for example, polyamide, polysulfone, polyethersulfone, polyetherimide, polyphenylene ether, polyimide, polyamideimide, preferably at least one selected from phenoxy, Among them, polyamide, polyetherimide, polyphenylene ether and polyether sulfone are particularly preferred.
[0061]
The thermoplastic resin becomes the main component of the particles, and the blending amount is preferably 70 to 100% by weight. More preferably, it is 75 to 97% by weight, still more preferably 80 to 95% by weight. If the amount is less than 70% by weight, it may be difficult to obtain a fiber-reinforced plastic having excellent impact resistance. When a thermoplastic resin is used as a main component, the adhesiveness of the particles to the fabric and the adhesive processability may be poor. In this case, a small amount of a tackifier, a plasticizer, or the like may be added to the particles.
[0062]
FIG. 3 is a schematic partially broken perspective view showing a preferred embodiment of the preform substrate 6 according to the present invention. The unidirectional woven fabric substrate 1 to which the particles 4 are adhered sequentially from the lower surface side in the figure. ₁ Is the woven fabric substrate 1 in the + α ° direction of the length direction of the preform substrate. ₂ In the 90 ° direction, the fabric substrate 1 ₃ Is in the -α ° direction, ₄ In the 0 ° direction, the woven fabric substrate 1 ₅ Is in the -α ° direction, ₆ In the 90 ° direction, the fabric substrate 1 ₇ In the + α ° direction, seven layers are cross-laminated so that particles exist between the layers, and these seven layers are stitched and integrated over the entire surface of the preform base material by stitch yarn 7 as an integrating means. . In addition, the integration means is not limited to stitching, and the particles adhered to the woven fabric substrate may be heated and spot-bonded in a spot shape to be integrated, but such a preform substrate has a curved surface. In this case, since the layers do not slide, the concave reinforcing fiber yarn is locally bent.
[0063]
When the layers are stitched together with a stitch thread, there is a degree of freedom in slipping between the layers, so that the reinforcing fiber yarns are not locally bent even along a curved surface, which is preferable. As a sewing structure formed by a stitch thread for stitch integration, single-ring sewing and 1/1 tricot knitting can be given. The stitch pitch of the stitch yarn in the length direction of the preform base material is preferably more than 1 mm and less than 6 mm, and can be appropriately selected in consideration of the handling properties and the shaping properties of the preform base material. The stitching interval of the stitch thread in the width direction of the preform base material is preferably more than 2 mm and less than 40 mm. In addition, the particles adhere to the woven fabric substrate used in the present invention, the reinforcing fiber yarns and the weft yarns adhere to each other, and the movement of the reinforcing fiber yarns is restrained, so to speak, in a state of being stopped. Therefore, when the needles of the stitches arranged linearly in the width direction on the woven fabric substrate laminated in the 90 ° direction pierce the reinforcing fiber yarns in the 90 ° direction at a narrow interval at a narrow interval, the reinforcing fiber at the location where the needle pierces In such a case, the reinforcing fiber of the yarn may be broken, so in such a case, the interval between the stitches is increased to more than 10 mm and less than 40 mm, and when the needle penetrates, the position of the reinforcing fiber yarn may be slightly escaped. preferable. In addition, if the stitching interval exceeds 40 mm, the preform base material is loosely restrained by the stitches and the form becomes unstable.
[0064]
When the reinforcing fiber yarn in the 90 ° direction is damaged by penetration of the needle, the arrangement of the needles in the width direction is adjusted so that about one or two needles pierce the reinforcing fiber yarn in the 90 ° direction. May be arranged in an oblique direction.
[0065]
The stitch yarn used in the present invention is preferably a multifilament yarn, and is, for example, nylon 6 fiber, nylon 66 fiber, nylon 11 fiber, nylon 12 fiber, polyester fiber, polyaramid fiber, polyetherimide fiber, or polyphenylene sulfide fiber. Nylon 66 is preferred because it has good adhesion to the resin and can be drawn to yield fine yarn. The fineness of the stitch thread is sufficient as long as it can withstand thread breakage during stitch processing and can be integrated by stitching. Preferably it is more than 14 dtex and less than 120 dtex. More preferably, it is more than 14 dtex and less than 85 dtex. If the thickness is too large, not only is the stitch portion protruded, so that a fiber-reinforced plastic having a smooth surface cannot be obtained, but also the stitch yarn has a large water absorption and poor heat resistance, so that the properties as a structural material deteriorate, which is not preferable. The stitch yarn used in the present invention is preferably removed by a scouring treatment or the like in order to improve the adhesion between the stitch yarn and the resin.
[0066]
FIG. 3 illustrates a preform base material in which the unidirectional woven base material is laminated into seven layers of a + α ° layer, a 90 ° layer, a −α ° layer, a 0 ° layer, a −α ° layer, a 90 ° layer, and a + α ° layer. However, the present invention is not necessarily limited to the lamination angle and the number of laminations. For example, there are 9 layers and many 0 ° layers such as 0 ° layer / + α ° layer / 0 ° layer / −α ° layer / 90 ° layer / −α ° layer / 0 ° layer / + α ° layer / 0 ° layer. May be included.
[0067]
In addition, the above-described preform base materials have all been described with reference to the uniform number of layers of 7 layers or 9 layers, but the number of layers may increase or decrease in the middle of the preform base material in the length direction. Good. In other words, the thickness of the structural material is not always constant. For example, the thickness of the skin material of an aircraft main wing skin is gradually reduced in the length direction as the distance from the fuselage increases. Therefore, in preparing a preform base material corresponding to the length of the main wing preform in advance, the -α layer, 90 ° layer, + α ° layer, and 0 ° layer are reduced one by one from the middle one by one based on the structural design. A preform substrate having no significant thickness change can be obtained. In particular, since the preform base material has a multilayer structure, in order to cope with changes in the thickness of the main wing, a preform base material with a uniform lamination number is replaced with a preform in which the number of preform base materials is reduced from the middle. Then, since the thickness of the preform base material per sheet is large, the thickness changes suddenly, and stress concentration occurs at the portion where the thickness changes rapidly, resulting in a decrease in strength, which is not preferable.
[0068]
Here, the bias angle α ° is preferably substantially 45 ° from the viewpoint of laminating the preform base material in the length direction of the fiber-reinforced plastic structure and effectively performing shear reinforcement by the reinforcing fibers. The order of the lamination angle is not particularly limited, but the cracks between the layers of the fiber reinforced plastic due to the impact in the thickness direction of the laminate due to the anisotropy of the mechanical properties of each layer are minimized, and the fiber reinforced plastic plate is From the viewpoint of reducing the decrease in the compressive strength, it is preferable that the intersection angle between the reinforcing fibers of the adjacent layers is 45 °.
[0069]
In the present invention, a preform is a laminate in which a large number of preform bases are laminated, a textile base and preforms are bonded to each other, and the preform bases are laminated without bonding. Called.
[0070]
It is preferable that the preform substrate is continuously laminated on the entire surface of the preform in order to prevent a cut portion of the reinforcing fiber thread from being inserted into the laminate of the preform substrate and the preform. For example, when forming a wide structure having a width of 5 m to 8 m, such as a skin material for a main wing of an aircraft, the width direction of the preform is set so that the 0 ° direction of the narrow preform base is the length direction of the main wing. The ends of the base material are overlapped and laminated. However, the weight of the overlapped portion is increased and not only the desired weight reduction cannot be achieved, but also the reinforcing fiber yarns in ± 45 ° direction and 90 ° direction are formed. It is not preferable because it breaks in the middle and stress concentration acts on the cut portion of the reinforcing fiber yarn, resulting in a decrease in strength. In addition, it is possible to laminate the preform base material laminate and the preform so that the edges of the preform base material do not overlap with each other without overlapping the ends of the preform base material. The reinforcing fiber yarn in the ° direction is broken in the middle, and stress concentration acts on the cut portion of the reinforcing fiber yarn, resulting in a decrease in strength, which is not preferable.
[0071]
Therefore, in the case of a wide structure such as a main wing, a wide preform base material corresponding to the main wing width is used to prevent the overlap of the preform base material and the insertion of a cut portion of the reinforcing fiber yarn. It is preferable that the layers are stacked without breaks.
[0072]
Next, an example of producing such a preform substrate will be described.
For example, when producing a preform base material laminated on seven layers of + α ° layer / 90 ° layer / −α ° layer / 0 ° layer / −α ° layer / 90 ° layer / + α ° layer, Seven long woven fabric base rolls in which reinforcing fiber yarns are arranged and wound around the rolls are prepared.
[0073]
Next, on both sides, there is a belt in which pins are linearly implanted, and the belt has + α ° with respect to the length direction of the preform substrate manufacturing machine moving to the stitching section and the winding section. Pull out the fabric substrate while fixing the end of the fabric substrate from the direction, hook the pin on the side opposite to the roll installation side, and cut both ends of the fabric substrate. Furthermore, while fixing the end of the woven fabric substrate, the woven fabric material is pulled out so that there is no gap between the woven fabric material that has already been pulled out and hooked on the pin, and the woven fabric material does not overlap. The both ends of the woven fabric substrate are cut, and this is repeated to form a + α ° layer. Next, the fabric substrate is drawn out from the 90 ° direction, a 90 ° layer is formed on the already formed + α ° layer, and a −α ° layer is similarly formed on the + α ° layer / 90 ° layer. . The 0 ° layer is supplied in parallel with the focus without being hooked on the pin, reaches the stitch portion, and temporarily stops on the −α ° layer until the position is fixed to form the 0 ° layer. The needle is penetrated at the stitch portion into a seven-layer laminate in which a + α ° layer, a 90 ° layer, and a + α ° layer are sequentially formed on the + α ° layer / 90 ° layer / −α ° layer / 0 ° layer. Then, the preform base material of the present invention is manufactured by stitching and integrating with a stitch thread. In addition, the number of laminations is not uniform in the length direction of the preform base material, and the preform base material that is increased or decreased from the middle is based on the structural design. It is possible to manufacture by increasing or decreasing the supply of the + α ° layer and the 0 ° layer.
[0074]
Since the particles are adhered to the woven fabric substrate used in the present invention, the reinforcing fiber yarns and the weft yarns are bonded in advance, and the movement of the reinforcing fiber yarns is restrained, so that it is in a so-called depressed state. When the preform base material is manufactured, the yarn arrangement is not disturbed. Further, even in the case of a thin woven fabric, the morphology of the woven fabric substrate is stabilized by the adhesion of the particles, and even when a wide preform substrate is produced, the woven fabric substrate does not wrinkle, and the quality is stable. It becomes possible to produce a preform substrate.
[0075]
In molding, the laminate of the woven fabric substrate is bulky due to sizing adhered to the reinforcing fiber yarns, entanglement of the reinforcing fibers, etc., and resin is injected into such a laminate by a vacuum bag molding method. However, since the pressing force is small and the laminate cannot be sufficiently held down, the resin component is large, that is, a fiber-reinforced plastic having a small volume content of the reinforcing fiber may be obtained. In such a case, for example, a preform in which a predetermined number of the preform substrates of the present invention are laminated is heated and pressed to a temperature higher than the melting point or glass transition temperature of the particles to increase the fiber density, and the reinforcing fiber volume ratio in the preform is increased. It is preferable that Vpf be more than 45% and less than 60%. When it is 45% or less, the impregnating property of the resin in vacuum impregnation is good, but it becomes a fiber reinforced plastic having a small fiber volume content, and the mechanical properties are lowered, making it difficult to reduce the weight of the structure. On the other hand, if it is 60% or more, the gap between the yarns or the fibers becomes small, and the resin hardly flows, which is not preferable.
[0076]
Here, the reinforcing fiber volume ratio Vpf indicates a value calculated by the following method.
Vpf = W1 / (ρ × T1) × 100 (%)
W1: Preform 1cm ² Weight of reinforcing fiber per unit (g / cm ² )
ρ: density of reinforcing fiber (g / cm ³ )
T1: Preform thickness (cm) measured under a load of 0.1 MPa in accordance with JIS7602
[0077]
The fiber volume content of the fiber-reinforced plastic molded product obtained by molding the preform subjected to the high fiber density treatment as described above is 52 to 62%, and is suitable for aircraft structural materials such as wing skin materials. The performance of fiber reinforced plastic can be fully exhibited.
[0078]
In addition, it is important that a gap between reinforcing fiber yarns of the unidirectional woven fabric substrate is secured in the preform substrate from the impregnating property of the resin. For example, a large number of preform substrates are laminated and bonded. In addition, even in the preform before resin impregnation, the state between the yarns changes due to the high fiber density treatment of the preform to reduce the bulkiness, and it is not preferable that the gap is reduced, and the gap is sufficiently secured. It is important that it is done. It is preferable that the gap between the yarns of the woven fabric substrate is a substantially uniform gap of more than 0.1 mm and less than 1 mm over the entire width of the woven fabric substrate of the preform. More preferably, it is more than 0.2 mm and less than 0.8 mm, and still more preferably more than 0.3 mm and less than 0.5 mm. Within such a range, the resin flows in the thickness direction of the preform, and the preform is impregnated with the resin. If the gap is smaller than this, the viscosity of the resin increases before the resin does not reach the whole, or the resin starts to be cured, a portion not impregnated with the resin occurs, and the molded article is rejected due to a defect. In particular, if a large plastic structure such as a wing is rejected, economic damage will be enormous. When the gap exceeds this range, the impregnation of the resin is good, but at the time of high fiber density treatment or molding, the reinforcing fiber yarns of the layer adjacent to the gap bite or fall, and the fabric base material, the preform Despite the fact that the reinforcing fiber yarns were arranged straight in the state of the base material, the molded product crimps (bends) due to biting or dropping of the yarns into the gaps, resulting in reduced mechanical properties. In addition, since the matrix resin enters the gap, the molded article becomes excessively resinous, and the excessively resinous part is cracked due to fatigue or the like, which is not preferable. If the gap between the yarns is within this range, the resin flows through the gap to the next layer, and the molded article having good resin impregnation and excellent mechanical properties can be obtained. It is. The gap is preferably substantially uniform over the entire width of the woven fabric substrate. If the gaps are non-uniform and large gaps are sparse, the resin from these gaps flows before other gaps, which is not preferable because an unimpregnated portion may be formed inside the preform.
[0079]
From the preform base material of the present invention, a laminate of the preform base material and the preform, a fiber-reinforced plastic can be molded by a conventionally known method. Among them, a resin transfer molding method and a vacuum bag molding method Is preferably used because a large molded product can be manufactured at low cost.
[0080]
Hereinafter, an embodiment of the method for producing the fiber-reinforced plastic of the present invention, which is formed by vacuum bag molding using the preform of the present invention, will be described.
[0081]
FIG. 4 is a cross-sectional view of one embodiment illustrating a molding method of the fiber-reinforced plastic of the present invention. In FIG. 4, a preform 9 is placed on a molding die 8, and a sheet to be removed by being peeled off after the resin is cured, a so-called peel ply 10, is laminated thereon, and the resin is diffused over the entire surface of the preform. The medium 11 for placing. Around the preform, a large number of porous materials such as woven fabrics are laminated, and an edge breather 13 provided with an air suction port 12 of a vacuum pump is stretched around the preform. The whole is covered with a bag film 14, and air leaks. The periphery of the bag film is adhered to the mold with a sealing material 15 so as not to cause any problem. A discharge port 17 for the resin injected from the resin tank is attached to the upper portion of the bag film, and the bag film is adhered with a sealing material 15 so that air does not leak from the attachment portion. The resin tank is filled with a thermosetting resin in a syrup at room temperature containing a predetermined amount of a curing agent. Next, the preform covered with the bag film is reduced to a vacuum pressure of about 93310 to 101325 Pa by a vacuum pump, and then the resin is injected by opening the valve 16. The inside covered with the bag film is in a decompressed state, and the resin flow resistance in the surface direction of the medium is smaller than that in the thickness direction of the preform. Therefore, the resin first spreads over the entire surface of the medium, and then in the thickness direction of the preform. Impregnation proceeds. With this method, the distance over which the resin must flow can be the thickness of the preform, so that the resin impregnation is completed very quickly. After completion of the resin impregnation, the valve 16 is closed and left at room temperature to cure the resin. After the resin is cured, the peel ply is peeled off, the medium and the bag film are removed, and the fiber-reinforced plastic molded article is obtained by removing the mold from the mold.
[0082]
FIG. 5 shows an example of the medium 11 used in the present invention. The medium transmits the resin to the upper surface of the preform on the medium side by transmitting the reduced pressure in the bag to the preform and passing the medium through the gap of the medium to be injected. That is, when the resin is injected into the medium located between the bag film and the peel ply, in FIG. 5, the injected resin flows through the gap of the X group of bars 18 in contact with the bag film in the direction of the bars 18 and at the same time, Since the resin flows in the gap between the bars 19 having the rectangular cross section in the direction of the bars 19, the resin is diffused in all directions. Further, since the force applied to the bar 17 can be transmitted to the bar 18, the reduced pressure can be transmitted to the preform. As a specific medium, a mesh sheet made of polypropylene, polyethylene, polyester, polyvinyl chloride, metal, or the like is used. For example, a mesh-like resin film, a woven fabric, a net-like material, a knitted fabric, and the like can be used by stacking several of them as necessary.
[0083]
Although the fibrous material has been described above as a preform, the fibrous material may be a preform substrate or a laminate of a plurality of preform substrates in the present invention.
[0084]
Although the molding method described above falls largely in the category of vacuum bag molding method, the conventional vacuum bag molding method is used in that the resin is diffused over the entire surface of the preform substrate laminate or the preform simultaneously with resin injection. Unlike the method, it is particularly suitable for use in molding large fiber-reinforced plastic molded articles.
[0085]
The peel ply used in the molding method of the present invention is a sheet that is peeled off and removed from the fiber-reinforced plastic after the resin is hardened, but it is necessary that the resin can be passed through, and nylon fiber woven fabric, polyester fiber woven fabric, glass A fiber fabric or the like is used. Nylon fiber woven fabrics and polyester fiber woven fabrics are preferably used because they are inexpensive, but in order to prevent oils and sizing agents used in manufacturing these woven fabrics from being mixed into the resin of the fiber-reinforced plastic, scouring is performed. In order to prevent shrinkage due to heating during curing, it is preferable to use a heat-set fabric.
[0086]
The edge breather used in the present invention needs to be able to pass air resin, and nylon fiber woven fabric, polyester fiber woven fabric, glass fiber woven fabric and a mat made of nylon fiber or polyester fiber can be used.
[0087]
Further, the bag film used in the present invention needs to be airtight, and a nylon film, a polyester film, a PVC film, or the like can be used.
[0088]
In the molding method of the present invention, a thermosetting resin which is liquid at room temperature, for example, an epoxy resin, a vinyl ester resin, a phenol resin or an unsaturated polyester resin is usually used. An epoxy resin is preferably used in order to obtain a fiber-reinforced plastic having high properties. If the resin viscosity of the epoxy resin is small, the heat resistance generally deteriorates, so even when the resin viscosity is slightly high at room temperature, the mold temperature during injection, the viscosity of the preform and the resin are preferably 70 to 100 ° C. It is preferable that the viscosity of the injected resin is reduced to 200 mPa · s or less. Subsequently, after the resin is injected, it is preferable to perform primary curing at about 130 ° C., advance polymerization of the epoxy resin, at least to a gel state, and then perform secondary curing at a high temperature of about 180 ° C. By this method, it is possible to mold a fiber-reinforced plastic having good resin impregnation, excellent heat resistance, and excellent mechanical properties such as toughness, strength, and elastic modulus.
[0089]
Although the application range of the fiber-reinforced plastic molded product obtained by the present invention is not particularly limited, it is suitably used as a primary structural member of an aircraft such as an aircraft main wing (skin, stringer), floor support, fuselage, horizontal tail and vertical tail. Used.
[0090]
【Example】
Example 1
As the reinforcing fiber yarn, the number of filaments is 24,000, the fineness of the yarn is 1,030 tex, the tensile strength is 5.8 GPa, the tensile modulus is 290 GPa, the sizing adhesion amount is 0.5% by weight, and the number of twists is substantially. Zero carbon fiber yarns are used as warp yarns, and 17 dtex nylon 66 filament yarn obtained by scouring glass fiber yarn to which a 22.5 dtex coupling agent is attached as a warp auxiliary yarn is used as a warp yarn for a number of twists of 250. Using a covering yarn covered at a number of turns / m, a nylon 66 filament yarn of 17 dtex, which has been refined as a weft and has substantially zero twists, and the warp density of the carbon fiber yarn and the auxiliary yarn Are 1.84 threads / cm each, the weft density is 3 threads / cm, and the carbon fiber weight is 190 g / m. ² A one-way non-crimp fabric was prepared. 27 g / m2 particles having an average diameter of 120 microns were placed on the upper surface of the woven fabric. ² Was uniformly dispersed and adhered to the surface of the fabric by heating at 200 ° C. to prepare a fabric substrate.
[0091]
The woven fabric base material is sequentially laminated in the −45 ° direction, the 90 ° direction, the + 45 ° direction, and the 0 ° direction, and a nylon 66 filament yarn of 78 decitex subjected to scouring processing is used as a stitch yarn. Was 10 mm and the pitch was 3 mm to prepare a preform substrate having four layers of woven fabric substrate. As a result of the measurement, the gap between the adjacent carbon fiber yarns of the textile base material constituting the preform base material was 0.4 mm.
[0092]
Example 2
The preform base material was cut so as to be 50 cm in each of the 0 ° direction and the 90 ° direction, and 33 pieces of the preform base material were laminated while matching the corners of the preform base material. This laminate was vacuum bagged with a film, and subjected to a high fiber density treatment in an atmosphere at 80 ° C. for 1 hour to obtain a preform having a carbon fiber volume ratio Vpf of 49%. The gap between adjacent carbon fiber yarns in the preform was 0.35 mm, which was slightly narrowed by the high fiber density treatment.
[0093]
Example 3
Next, the mold on which the epoxy resin and the preform were set was heated to 80 ° C., and the epoxy resin was injected for 1 hour. Then, the resin was primarily cured at 130 ° C. for 2 hours, and then secondary cured at 180 ° C. for 2 hours. After curing, vacuum bag molding was performed.
[0094]
The thickness of the obtained fiber-reinforced plastic molded plate is 25 mm, the volume content of carbon fiber is 55%, and the resin is impregnated in the entire preform. Thus, it was in a state of being sufficiently usable as a structural material.
[0095]
Comparative Example 1
The same carbon fiber yarns as in Example 1 were attached to the support at a density of 1.84 yarns / cm on a sheet arranged in parallel, and the carbon fiber weight was 190 g / m. ² Was produced. Note that the support is a mesh-like material in which an adhesive is attached to glass fiber 22.5 decitex glass fiber yarn and the distance between the vertical direction and the horizontal direction is 10 mm.
[0096]
Next, using this sheet, a comparative preform substrate was produced under the same conditions as in the example. There was no gap between the adjacent carbon fiber yarns of the one-way sheet constituting the comparative preform substrate, and it was 0 mm.
[0097]
Comparative Example 2
In the same manner as in Example 2, a preform subjected to a high fiber density treatment was produced. There was no gap between adjacent carbon fiber yarns in the preform, and it was 0 mm.
[0098]
Comparative Example 3
Next, a bag was formed in the same manner as in Example 3. When the bag film, the peel ply and the resin diffusion medium were peeled off and the molded body was observed, only the preform of about 1 mm on the resin diffusion medium side was impregnated with the resin. The resin was not impregnated.
[0099]
The obtained fiber reinforced plastic molded plate was not impregnated with the resin and was not in a very usable state as a structure.
[0100]
【The invention's effect】
As described above, according to the present invention, the following various effects can be obtained.
(1) The preform substrate of the present invention comprises a one-way woven substrate in which reinforcing fiber yarns are arranged in parallel in the length direction and particles are adhered to at least one surface, and the one-way woven substrate is provided. Are cross-laminated and integrated by the integrating means, so that a preform manufactured by laminating the layers in a multi-layer can be manufactured with a significantly reduced number of laminations, and can be manufactured inexpensively and with good productivity.
[0101]
In addition, since the impregnating property of the resin is good, it is possible to completely impregnate even a thick molded product, and particles are present between the woven fabrics, and a unidirectional woven fabric having a small crimp of the reinforcing fiber yarn is used. Thus, a fiber-reinforced plastic molded article having excellent impact fracture toughness and excellent mechanical properties such as tensile strength, tensile modulus, compressive strength, and compressive modulus can be obtained.
[0102]
(2) In the laminate of the preform and the preform substrate of the present invention, since the preform substrate is continuously laminated on the entire surface, the cut portion of the reinforcing fiber yarn does not exist in the preform and the laminate. A large molded body having excellent tensile strength and compressive strength can be obtained.
[0103]
(3) In the preform of the present invention, a predetermined number of preform base materials are laminated, the textile base material and the preform are adhered to each other, and the reinforcing fiber volume ratio Vpf in the preform is more than 45% and less than 60%. Thus, a molded article having good resin impregnation and a high fiber volume content can be obtained.
[0104]
(4) In the molding method of the present invention, the laminate of the preform base material and the preform are laminated in a mold, a medium for diffusing the resin in the surface direction is placed thereon, and the whole is covered with a bag film. Fiber reinforced, characterized in that the inside covered with the bag film is decompressed, liquid thermosetting resin is diffused on one side of the laminate and the preform, and the laminate and the preform are impregnated with the resin and cured. Since it is a plastic molding method, a large-sized molded body can be manufactured at low cost, and a molded body without voids can be obtained.
[Brief description of the drawings]
FIG. 1 is a schematic perspective view of a one-way woven fabric base constituting a preform base according to one embodiment of the present invention.
FIG. 2 is a schematic perspective view of a unidirectional woven fabric substrate constituting a preform substrate according to another embodiment of the present invention.
FIG. 3 is a schematic partially broken perspective view showing a preferred embodiment of a preform base material according to the present invention.
FIG. 4 is a cross-sectional view in one example illustrating a method for molding a fiber-reinforced plastic according to the present invention.
FIG. 5 is a schematic perspective view showing one embodiment of a resin diffusion medium used in the molding method of the present invention.
[Explanation of symbols]
1 unidirectional textile substrate
1 ₁ Unidirectional textile substrate (+ α ° direction with respect to the length direction of the preform substrate)
1 ₂ Unidirectional woven fabric substrate (90 ° direction to preform substrate length direction a)
1 ₃ Unidirectional woven fabric substrate (-α ° direction with respect to the length direction of the preform substrate)
1 ₄ Unidirectional woven fabric substrate (0 ° direction with respect to the length direction of the preform substrate)
1 ₅ Unidirectional woven fabric substrate (-α ° direction with respect to the length direction of the preform substrate)
1 ₆ Unidirectional woven fabric substrate (90 ° direction to preform substrate length direction a)
1 ₇ Unidirectional textile substrate (+ α ° direction with respect to the length direction of the preform substrate)
2 Reinforcing fiber yarn
3 weft
4 particles
5 Warp direction auxiliary yarn
6 Preform substrate
7 stitch thread
8 Mold
9 Preform
10 peel ply
11 Resin diffusion medium
12 Air suction port
13 Edge Breather
14 Bag film
15 Sealing material
16 valves
17 Resin outlet
18 Group X Bar
19 Group Y Bar
A Gap between reinforcing fiber yarns
I Preform substrate length direction

Claims (22)

The reinforcing fiber yarns are arranged in parallel with each other in the longitudinal direction, and are made of a unidirectional woven fabric substrate in which particles are adhered to at least one surface. A large number of the unidirectional woven fabric substrates are cross-laminated, and integrated by an integrating means. A preform substrate characterized in that the preform substrate is formed. In the preform substrate, the gap between the reinforcing fiber yarns adjacent to the one-way woven fabric substrate is a substantially uniform gap of more than 0.1 mm and less than 1.0 mm in the entire width of the woven fabric, The preform substrate according to claim 1. The one-way woven fabric intersects the reinforcing fiber yarns on both sides of the sheet surface of a yarn group in which the reinforcing fiber yarns having no bend such that stress is concentrated are aligned in one direction in parallel with each other in a sheet shape. A weft direction auxiliary yarn group is located, and the weft direction auxiliary yarn group and the warp direction auxiliary yarn group parallel to the reinforcing fiber yarn form a woven structure, and are a unidirectional non-crimp fabric in which the yarn group is integrally held. The preform substrate according to claim 1, wherein: The preform substrate according to any one of claims 1 to 3, wherein the integration means is a stitch. The preform substrate according to any one of claims 1 to 4, wherein the cross lamination angle includes at least 0 ° layer with respect to the length direction of the preform substrate. The preform substrate according to any one of claims 1 to 5, wherein the crossing lamination angle includes at least two directions of a + α ゜ layer and a -α ゜ layer with respect to a length direction of the preform base material. Wood. The preform substrate according to any one of claims 1 to 6, wherein the number of laminations is not uniform in the longitudinal direction of the preform substrate, but increases or decreases in the middle. The preform substrate according to any one of claims 1 to 7, wherein the reinforcing fiber yarn is made of carbon fiber. The number of filaments of the carbon fiber is more than 12,000 and less than 25,000, the tensile modulus of the carbon fiber is more than 280 GPa and less than 500 GPa, and the breaking strain energy is 53 MJ / m ³ or more. The preform substrate according to claim 8, wherein: 5. The unidirectional woven fabric substrate has a warp yarn of carbon fiber yarn, a fineness of the weft direction auxiliary yarn of more than 6 decitex and less than 70 decitex, and a density of the weft direction auxiliary yarn of more than 0.3 / cm. less than 0 present / cm, and wherein the basis weight of the carbon fibers is less than 350 g / ^{m 2} exceed 100 g / ^{m 2,} preform substrate according to claim 8 or 9. The fineness of the weft direction auxiliary yarn is more than 15 dtex and less than 50 dtex, the density of the weft direction auxiliary yarn is more than 1.0 yarn / cm and less than 4.0 yarn / cm, and the basis weight of the carbon fiber is 180 g / cm2. and less than 210g / ^{m 2} exceed m ^2, preform substrate of claim 10. The preform according to any one of claims 1 to 11, wherein the particles have a function of imparting interlayer toughness of a fiber-reinforced plastic, and have a melting point or a glass transition temperature of more than 50 ° C and less than 150 ° C. Base material. The preform according to any one of claims 1 to 12, wherein the attached amount of the particles is more than 2% and less than 20% based on the weight of the reinforcing fibers constituting the unidirectional woven fabric substrate. Base material. A laminate, wherein a plurality of the preform substrates according to any one of claims 1 to 13 are laminated, and each of the preform substrates is continuously laminated over the entire surface of the laminate. A preform, wherein a plurality of the preform substrates according to any one of claims 1 to 13 are laminated, and the woven substrate and / or the preform substrate are adhered to each other. The preform according to claim 15, wherein the preform base material is continuously laminated over the entire surface of the preform. The preform according to claim 15 or 16, wherein the reinforcing fiber volume fraction Vpf in the preform is more than 45% and less than 60%. The gap between the reinforcing fiber yarns adjacent to the one-way woven fabric substrate constituting the preform is more than 0.1 mm and less than 1.0 mm, according to any one of claims 15 to 17, Preform of description. A predetermined number of preform substrates according to any one of claims 1 to 13 are laminated in a molding die, or a laminate of the preform substrate according to claim 14 is disposed in a molding die, and a resin is placed thereon. After placing the medium that diffuses in the plane direction, cover the whole with a bag film, then put the inside covered with the bag film under reduced pressure, and diffuse the liquid thermosetting resin to one side of the laminated preform base material. A method of impregnating a preform substrate with a resin and curing the resin. The preform according to any one of claims 15 to 18 is laminated on a mold, a medium for diffusing the resin in the surface direction is placed on the preform, the whole is covered with a bag film, and then covered with a bag film. A method for molding a fiber-reinforced plastic, wherein the inside of the preform is depressurized, a liquid thermosetting resin is diffused on one side of the laminated preform, and the preform is impregnated with the resin and cured. 21. The thermosetting resin according to claim 19, wherein the thermosetting resin is an epoxy resin, and heats the resin and the mold and the preform base material or preform to lower the resin viscosity and improve the resin impregnation property. Molding method of fiber reinforced plastic. A fiber-reinforced plastic molded article obtained by the molding method according to claim 19.

Images