JP2006138031A - Reinforcing fiber substrate, preform and method for producing them - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To obtain a reinforcing fiber substrate that provides a composite material having not only excellent handleability such as shape stability, etc., but also high mechanical properties and has excellent impregnation properties of matrix resin and a preform and to provide methods for producing them. <P>SOLUTION: The reinforcing fiber substrate comprises a reinforcing fiber yarn group obtained by arranging at least continuous reinforcing fiber yarns in one direction in parallel in which spaces passing through the reinforcing fiber yarns in the thickness direction of the reinforcing fiber substrate are formed. The preform is obtained by using the reinforcing fiber substrate. The methods for producing the reinforcing fiber substrate and the preform are provided. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a reinforced fiber base material, a preform suitable for molding a fiber reinforced plastic (hereinafter sometimes referred to as FRP), and a method for producing the same. More specifically, in the production of high-quality FRP by a molding method such as RTM or VaRTM described later, the matrix resin is well impregnated despite the high fiber volume content (Vf), and excellent mechanical properties ( In particular, the present invention relates to a reinforcing fiber base material, a preform and a method for producing the same, which can cause CAI).

  Conventionally, as a manufacturing method of FRP that requires high quality such as aircraft structural members, a prepreg in which a reinforcing fiber base material is impregnated with a matrix resin in advance is used, and this is laminated on a mold and covered with a bag film. An autoclave molding method in which a resin is cured by heating and pressurizing in a (heating and pressing furnace) is frequently used. This molding method is preferably used because even in FRP, there is little generation of voids, and it is possible to form a homogeneous and high quality product.

  However, in recent years, in order to reduce molding and material costs, instead of using an autoclave, a reinforced fiber base material in a dry state is set in a cavity formed between the upper die and the lower die, and the pressure in the clearance is reduced by vacuum. Resin Transfer Molding process (hereinafter referred to as RTM), which injects liquid matrix resin, or a laminated reinforcing fiber substrate in a dry state on a mold, covered with a bag film, and the bag is evacuated. Injection molding methods such as a so-called vacuum assisted resin transfer molding process (hereinafter referred to as VaRTM) in which a resin is injected are being applied to structural members and the like.

  In the above RTM, etc., the productivity of the composite material is excellent, but since it is necessary to impregnate the resin into the reinforcing fiber base in the dry state, the resin impregnation is performed when the number of laminated layers is large (when the thickness of the FRP is thick). It is necessary to use a low-viscosity resin as a matrix resin, and there is a problem that the mechanical properties are inferior to a high-viscosity resin used for a prepreg.

  For such problems, Patent Documents 1 and 2 and Non-Patent Documents 1 and 2 describe a technique in which a thermoplastic resin layer is disposed in a state having a gap between preforms laminated with reinforcing fiber substrates, and an epoxy resin. While improving the mechanical properties (such as delamination resistance and interlaminar fracture toughness) of composite materials obtained by RTM, etc., by applying a resin composition containing styrene and thermoplastic resin particles onto a reinforcing fiber fabric, Technologies for ensuring good impregnation properties have been proposed.

However, in the above proposal, the impregnation property of the matrix resin is greatly reduced by the thermoplastic resin layer arranged to improve the mechanical characteristics or the resin composition in which the epoxy resin and the thermoplastic resin particles are blended. As a result, the high productivity that is the original purpose cannot be obtained. That is, the reinforcing fiber base material and preform that can achieve both the mechanical properties and the impregnation property of the matrix resin have not been achieved by the above proposal, and a technique that can solve both of these problems has been desired.
International Patent Publication No. WO00-61363 (Claim 1) International Patent Publication No. WO03-04-758 (Claim 1) Journal of Advanced Materials, Volume 32, No.3, July 2000, P27-34 Composites part A, Volume 32, 2001, P721-729

  An object of the present invention is not only to solve the above-mentioned problems of the prior art, that is, not only excellent in handling properties such as form stability but also high mechanical properties (in particular, after compression impact, hereinafter referred to as CAI). It is to provide a reinforced fiber substrate, a preform and a method for producing the same, which are excellent in impregnation of a matrix resin.

  In order to solve the above-mentioned problems, the reinforcing fiber base according to the present invention includes at least a reinforcing fiber base composed of a group of reinforcing fiber yarns arranged so that continuous reinforcing fiber yarns are arranged in parallel in one direction. And the space which has penetrated the reinforcing fiber yarn is formed in the thickness direction of the reinforcing fiber substrate. Preferably, the reinforcing fiber base material is adhered to at least one surface of the resin material with a gap, and the adhesion amount is 2 to 15% by weight. It is.

  In the preform according to the present invention, two or more layers of such reinforcing fiber bases are laminated, and the laminated reinforcing fiber bases are at least partially bonded and integrated by a resin material. It consists of what is characterized by this.

  Further, the preform according to the present invention has at least two layers of reinforcing fiber yarns composed of a group of reinforcing fiber yarns arranged such that continuous reinforcing fiber yarns are aligned in parallel in one direction, and at least A preform that is partially bonded and integrated, and at least a reinforcing fiber yarn in the outermost reinforcing fiber base has a space penetrating in the thickness direction of the preform. It is made up of.

  The method for producing a reinforcing fiber base according to the present invention forms a reinforcing fiber cloth form using reinforcing fiber yarns, and has a protrusion while forming a reinforcing fiber base after bonding or adhering a resin material. To penetrate the pin from the surface of the reinforcing fiber base and form a space that penetrates in the thickness direction of the reinforcing fiber base, or to form a space that penetrates in the thickness direction of the reinforcing fiber base by irradiation with laser light It consists of a characteristic method.

  In addition, the preform manufacturing method according to the present invention includes a pin having a protrusion while forming a preform after or while adhering reinforcing fiber substrates to each other with a resin material adhering to the reinforcing fiber substrate. It consists of a method characterized by forming a space penetrating from the surface of the reinforcing fiber base and penetrating in the thickness direction of the preform, or forming a space penetrating in the thickness direction of the preform by laser light irradiation. .

  According to the reinforcing fiber substrate according to the present invention, the reinforcing fiber substrate is composed of continuous reinforcing fiber yarns, and a space penetrating the reinforcing fiber yarns is formed in the thickness direction of the reinforcing fiber substrate. Therefore, when a composite material is molded by RTM or VaRTM using the laminate of the reinforcing fiber base material, the resin impregnation is promoted through the penetrating space, and the resin impregnation property is excellent and high mechanical properties are obtained. can get. Furthermore, when the resin material adheres at least on the surface of the reinforcing fiber base with a gap, the handleability is good at the time of work and further excellent mechanical properties (especially CAI) can be obtained.

  Further, according to the preform according to the present invention, the reinforcing fiber bases are at least partially bonded and integrated with each other by the resin material, so that the handling property is excellent and the productivity of the composite material is excellent. it can.

  Further, according to the method for producing a reinforcing fiber base according to the present invention, after the reinforcing fiber base is formed using the reinforcing fiber yarn so as to satisfy the requirements of the reinforcing fiber base and the resin material is bonded, or A pin having protrusions is penetrated from the surface of the reinforcing fiber base while being bonded, or a space penetrating the reinforcing fiber base is formed by irradiation with a laser beam, so that it has excellent resin impregnation properties and high mechanical properties ( In particular, a reinforcing fiber base from which a CAI composite material can be obtained can be produced easily and reliably.

  Furthermore, according to the method for manufacturing a preform according to the present invention, the preform is formed while forming the preform after bonding the reinforcing fiber bases to each other or by bonding them with the resin material bonded to the reinforcing fiber base. Because the pin penetrates from the surface of the reinforcing fiber base or forms a space penetrating in the thickness direction of the preform by laser irradiation, a pull foam with excellent handling and resin impregnation can be manufactured easily and reliably. can do.

In the following, preferred embodiments of the present invention will be described with reference to the drawings, with reference to the preferred embodiments of the reinforcing fiber base according to the present invention.
FIG. 1 is a perspective view of a reinforcing fiber base according to an embodiment of the present invention. FIG. 2 is a schematic diagram of an AA ′ cross section along the reinforcing fiber yarn in a direction parallel to the longitudinal direction of the reinforcing fiber yarn in the reinforcing fiber substrate of FIG. 1.

  In FIG. 1, the reinforcing fiber base 1 has weft auxiliary fibers 3 which are weft yarns in a direction intersecting with the reinforcing fiber yarns 2 which are warp yarns oriented in parallel in the longitudinal direction, in the present embodiment in the orthogonal direction. The reinforcing fiber yarns 2 are formed on a reinforcing fiber fabric 4 made of a unidirectional woven fabric arranged alternately up and down for each one of the reinforcing fiber yarns 2. As shown in FIG. 2, the resin material 5 is attached in a form having a gap over substantially the entire surface of at least one side of the reinforcing fiber base 1 and penetrates the reinforcing fiber yarn 2. A space 6 is formed.

  In the present invention, since a space (dotted in FIG. 1) penetrating the reinforcing fiber yarns is formed in the thickness direction of the reinforcing fiber base material, the dry preform is impregnated with the liquid resin. The resin injected into the fiber can be impregnated in the thickness direction of the reinforcing fiber substrate through the space penetrating the reinforcing fiber yarns while diffusing in the in-plane direction of the reinforcing fiber substrate. Impregnation is possible.

  Moreover, it is preferable that the form of the space that penetrates the reinforcing fiber yarn in the thickness direction of the reinforcing fiber base is linear (more precisely, a line segment) or a point when viewed in a plan view. If the penetrating space is dotted, there is an advantage that this substrate can be easily manufactured (details will be described later). On the other hand, if it is linear, the space that penetrates can be made larger, so that the impregnation property of the resin can be made higher than that of the dot shape. In particular, when the linear orientation direction is parallel to the reinforcing fiber yarn, damage to the reinforcing fiber yarn (the number of reinforcing fiber filaments to be cut) can be minimized, which is preferable in the present invention. It can be called an aspect.

  Further, the arrangement of the penetrating spaces may be any arrangement such as a staggered arrangement or a line arrangement, but is preferably an irregular arrangement. That is, if the through space is arranged in a fixed pattern such as a staggered arrangement, the position of the through space may overlap when the reinforcing fiber base material is laminated, and the thickness of the laminated body in the overlapping portion Since the impregnation in the direction is accelerated at once, the progress of the resin impregnation is not uniform, and a local unimpregnated spot may be easily formed. When the penetrating spaces are irregularly arranged, the resin impregnation can proceed from different positions for each reinforcing fiber base so that the effect of the present invention can be exhibited to the maximum. become.

  FIG. 3 shows an example of a preform 7 in which a plurality of layers of the reinforcing fiber base material of the present invention are laminated, and a schematic cross-sectional view cut along the reinforcing fiber yarn. When the penetrated spaces 6 are irregularly arranged as shown in FIG. 3, the resin impregnation proceeds from different positions for each reinforcing fiber substrate, and the laminate of reinforcing fiber substrates is formed. The entire preform 7 can be uniformly impregnated with the resin.

Average area projected in the planar direction of the space through the reinforcing fiber yarns in the reinforcing fiber substrate and below the preform is preferably 0.1 to 10 mm ^2/1 space. In FIG. 1, since the penetrated space is dot-like, the average area corresponds to the average value of the area of a circle or an ellipse. If the average area is less than 0.1 mm ² , the resin impregnation rate is slow because the area is too small, and the effect of improving the resin impregnation due to the formation of the space may not be sufficiently obtained. On the other hand, when the thickness exceeds 10 mm ² , the resin impregnation speed is improved, but when a composite material is used, the space portion becomes a resin-rich portion, and when stress concentration occurs, it tends to be a starting point of fracture. In addition, when the area is increased, the number of reinforcing fiber filaments that are cut to form this space increases, and mechanical characteristics are likely to deteriorate when the composite material is formed. For this reason, it is preferable that the area projected to the plane direction of the space which the reinforcement fiber base penetrated is 0.1-10 mm < ² > / 1 space.

Moreover, it is preferable that the total area projected in the plane direction of the space which penetrated in the reinforcing fiber base material or the preform described later is 0.05 to ⁵ mm ² per 100 mm ² . If the total area is less than 0.05 mm ² , the area of the space is too small, so that the resin impregnation speed is slow, and the effect of improving the resin impregnation due to the formation of the space may not be obtained. On the other hand, if it exceeds 5 mm ² , the space occupies a large proportion, and the resin impregnation speed is improved, but when a composite material is used, the space portion becomes a resin-rich portion and stress concentration occurs. It becomes easy to become. Further, when the total area is increased, the number of reinforcing fiber filaments to be cut to form this space is increased, and mechanical characteristics are likely to be deteriorated when the composite material is formed. For this reason, it is preferable that the total area projected in the plane direction of the penetrated space is 0.05 to ⁵ mm ² per 100 mm ² .

In the present invention, the total area of the space that penetrates the reinforcing fiber yarn is obtained by multiplying the area of the space that penetrated in a certain area as viewed from the upper surface of the base material by converting the number into a value at 100 mm ² . It is.

  Here, the measurement of the area projected in the plane direction of the penetrating space is a non-contact type or contact type length measurement if the shape is a circle, the diameter if it is an ellipse, the length of the major axis and the minor axis. By measuring with a vessel, the area can be calculated. As another method, it is also possible to obtain an image captured by a CCD camera by performing an area calculation process using an image processing system.

Moreover, it is preferable that the total number projected to the plane direction of the space which penetrated in the reinforcing fiber base material or the below-mentioned preform is 0.05-2 per 100 mm < ² >. If the total number is less than 0.05, the area of the space is too small, so the resin impregnation rate is slow, and the effect of improving the resin impregnation due to the formation of the space may not be obtained. On the other hand, if the number exceeds two, the space occupies a large proportion, and the resin impregnation speed is improved. However, when a composite material is used, this space becomes a resin-rich part and stress concentration occurs. It becomes easy to become. In addition, when the area is increased, the number of reinforcing fiber filaments that are cut to form this space increases, and mechanical characteristics are likely to deteriorate when the composite material is formed. For this reason, it is preferable that the total number projected to the plane direction of the space which the reinforcement fiber base penetrated is 0.05-2 per 100 mm < ² >.

  Furthermore, if the shape of the space is linear and the longitudinal direction of this space is parallel to the array direction of the reinforcing fibers, the number of reinforcing fibers to be cut is small, so that the mechanical characteristics when made into a composite material Since the decrease in resistance is small and the area of the penetrating space can be increased, the resin impregnation property can be improved.

  When the penetrating space is within the above range, improvement in mechanical properties (formation of resin-rich portion and damage of reinforcing fiber yarn) and resin impregnation can be achieved at a high level, and this is a preferable aspect of the present invention. it can.

  In the reinforcing fiber base of the present invention, it is preferable that a resin material adheres to at least one surface of the reinforcing fiber cloth. That is, when the resin material adheres to the fabric surface, a function of bonding and integrating the base materials when the reinforcing fiber base materials are laminated to obtain a preform is exhibited. In addition, misalignment of the reinforcing fiber yarn formed on the fabric is prevented, and the base material has excellent shape stability. Furthermore, by adhering the resin material, the space formed so as to penetrate the fiber yarn of the base material is fixed by the resin material, and it is possible to prevent the space from being blocked when the reinforcing fiber base material is handled. . The shape maintaining effect of the space that penetrates by such a resin material is a new effect found by the present inventors, and can be said to be one of the major features of the present invention.

  From the standpoint of mechanical properties, at least when the resin material is bonded to the surface of the fabric, the compression property after application of impact of the composite material having a pseudo isotropic laminated structure formed by laminating a plurality of sheets ( Excellent CAI). Such CAI is a mechanical characteristic that is very important when a composite material is used as an aircraft structural member (particularly a primary structural member).

  The resin material used in the present invention plays a role of a crack stopper and a role of relieving residual stress of the composite material in a composite material obtained by laminating reinforcing fiber base materials. In particular, when the composite material receives an impact, it plays a role of suppressing damage between the base material layers, and provides excellent mechanical properties (especially CAI), that is, a toughening effect.

  In addition to the toughening effect, at least if the resin material is bonded to the surface of the fabric, when the base material is laminated, the resin material adhering to the fabric surface becomes a spacer, and between adjacent base materials To form a space. This is referred to as a spacer effect by a resin material, and this spacer effect serves to form a flow path of the matrix resin when injected into the base material on which the matrix resin is laminated. This not only facilitates the impregnation of the matrix resin into the substrate, but also increases the impregnation rate, leading to excellent productivity of the composite material.

  The toughening effect, spacer effect, and the like by the resin material are exhibited at a higher level when the resin material is unevenly distributed on the surface of the base material, particularly when the resin material is substantially present only on the surface of the fabric. The

  In the case where the reinforcing fiber base is used as a single layer, the resin material may be bonded to one side or may be bonded to both sides. When manufacturing a base material at lower cost, the former is preferable. The latter is preferred when you do not want to use the front and back of the substrate properly.

  In the present invention, the space penetrating the reinforcing fiber yarns in the thickness direction of the reinforcing fiber substrate is not necessarily at a different position for each reinforcing fiber substrate, and a plurality of sheets called multi-stacks are required. A space penetrating the reinforcing fiber yarns in the thickness direction of the multilayer material may be formed in the multilayer material in which the reinforcing fibers are partially bonded and wound around a paper tube or the like. Moreover, you may form the space which has penetrated the reinforced fiber fiber thread | yarn in the thickness direction of the preform mentioned later.

  When reinforcing fiber base materials are laminated in multiple layers and used in the form of a multilayer base material, only the base material located in the center layer of the laminate is adhered to both sides, and the other layers are adhered to only one side. Since a resin material can be disposed between the layers of the laminate, it can be said to be one of the preferred embodiments of the present invention.

  The resin material is bonded in a state having a gap. That is, it is a dot, line or discontinuous line. In order to adhere in a dotted manner, the powder is preferably dispersed on the surface of the reinforcing fiber base and heat-sealed. Moreover, in order to make it adhere in a linear form or a discontinuous linear form, after producing the fabric which consists of continuous fibers, such as a nonwoven fabric and a textile fabric, it is good to stick and heat-seal on the surface of a reinforced fiber base material. By doing so, it has appropriate adhesiveness in preform production and does not hinder impregnation of the resin in the thickness direction of the reinforcing fiber base during molding of the composite material.

  In the reinforcing fiber base, 2 to 15% by weight of the resin material is adhered to at least one surface of the reinforcing fiber base. More preferably, it is 6-14 weight%, More preferably, it is 8-13 weight%. By having the resin material in the above range, higher morphological stability of the substrate is brought about. Furthermore, when the base materials are laminated, tackiness (adhesiveness) between the base materials and appropriate stiffness of the base materials are brought about. As a result, it is possible to obtain a reinforced fiber base material that is excellent in form stability, can be easily laminated, and can be automated. Such characteristics are less likely to be manifested at less than 2% by weight. On the other hand, if it exceeds 15% by weight, the impregnation property of the resin is essentially lowered, so that the effects of the present invention may not be exhibited.

  The resin material adhering to the surface of the reinforcing fiber base is a thermosetting resin, a thermoplastic resin, or a mixture thereof. When only adhesiveness as a preform is required, a thermosetting resin or a thermoplastic resin may be used alone. However, when impact resistance such as CAI is required, the toughness is excellent. When using a mixture of a thermoplastic resin and a thermosetting resin that is easy to lower the viscosity and easy to adhere to the reinforcing fiber base, it has appropriate adhesiveness to the reinforcing fiber sheet while having appropriate toughness. preferable. As the thermosetting resin, an epoxy resin, an unsaturated polyester resin, a vinyl ester resin, a phenol resin, or the like can be used. As thermoplastic resins, polyvinyl acetate, polycarbonate, polyacetal, polyphenylene oxide, polyphenylene sulfide, polyarylate, polyester, polyamideimide, polyimide, polyetherimide, polysulfone, polyethersulfone, polyetheretherketone, Polyaramid, polybenzimidazole, polyethylene, polypropylene, cellulose acetate, cellulose butyrate and the like can be used.

  The reinforcing fiber yarn constituting the reinforcing fiber substrate used in the present invention is a high-strength, high-modulus fiber such as carbon fiber, glass fiber, aramid fiber or PBO (polyparaphenylene benzobisoxazole) fiber. Among these, carbon fiber is more preferable because it has higher strength and higher elastic modulus among these fibers, and thus a composite material having excellent mechanical properties can be obtained. More preferably, when the carbon fiber has a tensile strength of 4500 MPa or more and a tensile elastic modulus of 250 GPa or more, more excellent composite characteristics can be obtained.

  Further, as a form of the reinforcing fiber fabric, a non-woven structure (so-called tow sheet) in which reinforcing fiber yarns are arranged so as to cross or entangle in one direction or two directions, or reinforcing fiber yarns in one direction or two directions. An woven structure (unidirectional woven fabric or bi-directional woven fabric) arranged. Among these, unidirectional fabrics using reinforcing fiber yarns for warp yarns and thin auxiliary yarns (auxiliary fibers) for weft yarns have excellent straightness of the reinforcing fiber yarns, so that excellent composite properties can be obtained and warp yarns. It is preferable because voids are formed between parallel reinforcing fibers by crossing of the weft yarns and an appropriate resin path in the thickness direction of the substrate can be formed.

  Especially, when a composite material is used for structural members, such as an aircraft, a unidirectional non-crimp fabric is preferable. Such unidirectional non-crimp fabrics are described in detail in, for example, Japanese Patent No. 3279049 and Japanese Patent Application Laid-Open No. 2003-82117.

  Further, as the weft direction auxiliary yarn in the unidirectional woven fabric or the unidirectional non-crimp woven fabric, a fine fiber having a fineness of 5 to 500 dtex is preferable. When the fineness is small, the warp crimp due to the presence of the weft yarn can be minimized, which is preferable. In particular, if the single yarn diameter of the auxiliary yarn is 10 to 100 μm and the number of twists is 50 turns / m or less, the weft direction is interlaced by the tension acting on the reinforcing fiber yarn when producing the reinforcing fiber fabric. This is preferable because the auxiliary yarn is pressed down, and the single weft-direction auxiliary yarns are arranged in a straight line and the surface irregularities can be reduced.

  The type of yarn is not particularly limited because it is for holding parallel reinforcing fiber yarns together, inorganic fiber such as carbon fiber and glass fiber, polyaramid fiber, vinylon fiber, polyester fiber, polyamide fiber Organic fibers such as can be used.

  Moreover, it is preferable that the yarn width of the reinforcing fiber yarn in the reinforcing fiber fabric is 2 to 10 mm. This is because the cross-sectional shape of the reinforcing fiber yarns is elliptical, and the gaps between the reinforcing fiber yarns arranged in parallel to each other serve as a flow path for the matrix resin in the thickness direction of the reinforcing fiber substrate. The pitch between the fiber yarns is increased, and the number of resin flow paths in the thickness direction of the substrate is reduced, so that the impregnation property of the matrix resin is lowered. In addition, when the yarn width is small, the pitch between the reinforcing fiber yarns is reduced, and the number of resin flow paths in the thickness direction of the base material is increased. There is a problem of high prices. For this reason, it is preferable that the yarn width of the reinforcing fiber yarn in the reinforcing fiber fabric is 2 to 10 mm. More preferably, it is 4-8 mm.

  Moreover, it is preferable that the volume fraction Vff of the reinforcing fiber calculated | required from the thickness of a reinforcing fiber base material is 35 to 65%. More preferably, it is 38 to 63%, and particularly preferably 40 to 63%. Here, the thickness of the reinforcing fiber substrate is a thickness measured according to JIS R7602 (test method for carbon fiber fabric), and the thickness when a pressure of 50 kPa is applied for 20 seconds is measured at five locations. It is expressed by the average value.

  When the volume ratio Vff of the reinforcing fiber is less than 35%, VaRTM in which the matrix resin is impregnated particularly by vacuum pressure does not apply a pressure higher than the atmospheric pressure, so the volume of the substrate, that is, the volume ratio Vff of the reinforcing fiber is desired. It cannot be controlled within the range, and the reinforcing fiber volume content Vf of the obtained composite material cannot be controlled to 50 to 65% suitable for mechanical properties, and a composite material having a desired thickness cannot be obtained. Furthermore, the base material layer in the resulting composite material is swelled, and the mechanical properties of the resulting composite material, particularly the compressive strength, are significantly reduced. This problem is related to the laminated structure, in the case where the laminated structure of the base material layer is a slanted laminated structure, for molding, only one of the male mold and the female mold is used and a flexible back material is used for the other. It becomes particularly obvious. That is, when Vff is less than 35%, a composite material that is excellent in mechanical properties and exhibits a high weight reduction effect cannot be obtained.

  On the other hand, when the volume fraction Vff of the reinforcing fibers exceeds 65%, in the case of VaRTM, the reinforcing fibers that are packed too tightly inhibit the flow of the matrix resin, thereby forming a space penetrating the reinforcing fiber yarns. However, the impregnation property of the resin is deteriorated, and only a composite material having an unimpregnated portion (void) can be obtained.

  By controlling the volume fraction Vff of the reinforcing fibers to be in the range of 35 to 65%, the reinforcing fiber volume content Vf and dimensions in the obtained composite material are strictly controlled to a desired range, and high mechanical properties are expressed. It becomes possible to do.

In addition, the reinforcing fiber volume fraction Vff calculated from the thickness of the reinforcing fiber substrate in the present invention (JIS R7602) refers to a value obtained by the following formula (unit:%). The symbols used here are as follows. Here, the base material to be used for the measurement is one that has been substantially saturated in the amount of springback after at least 24 hours has elapsed since it was manufactured.
Vff = W / (ρ × Tf × 10) (%)
W: Weight of reinforcing fiber per 1 m ² of reinforcing fiber substrate (g / m ² )
ρ: density of reinforcing fiber (g / cm 3)
Tf: Reinforced fiber base material thickness measured in accordance with JIS R7602 (mm)

  The preform according to the present invention is obtained by laminating two or more layers of the reinforcing fiber base material, and the reinforcing fiber base materials are at least partially bonded and integrated with each other by a resin material. .

  In the preform of the present invention, at least a part of the reinforcing fiber base composed of a group of reinforcing fiber yarns in which continuous reinforcing fiber yarns are aligned in parallel in one direction is laminated, The preform is bonded and integrated, and a space penetrating in the thickness direction of the preform is formed at least in the reinforcing fiber yarn in the outermost reinforcing fiber substrate.

  Here, when such adhesion extends over the entire surface of the reinforcing fiber base, the formability of the preform and the shape followability may be inferior, or the impregnation of the matrix resin may be hindered. Such adhesion is only required to be handled as a preform in which a plurality of laminated reinforcing fiber substrates are integrated, and it is preferable that the substrates are partially bonded to each other.

  In addition, at least the outermost layer (the layer that forms the outermost surface) of the preform can be used without using a reinforcing fiber substrate that has a space penetrating in the thickness direction of the reinforcing fiber substrate. If the space penetrated in the preform thickness direction is formed in the reinforcing fiber yarn in the reinforcing fiber base of (), the effect of the present invention can be achieved. With such a preform configuration, when the preform is filled into the mold and the liquid resin is injected into the mold, the resin is impregnated from a large number of spaces penetrating in the thickness direction of the reinforcing fiber base on the preform surface. Therefore, the preform can be impregnated with the resin in a short time.

  The method for producing a reinforced fiber base material according to the present invention includes forming a reinforced fiber base material using reinforced fiber yarns, and forming protrusions while forming the reinforced fiber base material after or after bonding the resin material. A pin is penetrated from the surface of the reinforcing fiber base to form a space penetrating in the thickness direction of the reinforcing fiber base. In addition, a space that penetrates the reinforcing fiber base by irradiation of laser light while forming a reinforcing fiber base using a reinforcing fiber yarn and forming a reinforcing fiber base after bonding or adhering a resin material. Is formed.

  More specifically, a reinforced fiber fabric is formed through a weaving process or the like by drawing a large number of reinforcing fiber yarns from a bobbin mounted on a creel stand or the like. Then, after applying or bonding a solid resin material to the reinforcing fiber cloth, the resin material is melted and bonded to form a reinforcing fiber substrate. In this case, the resin material may be a powder or a fabric such as a nonwoven fabric, a woven fabric, or a knitted fabric. Then, after bonding the resin material to the reinforcing fiber cloth or while forming the reinforcing fiber substrate, the pin having the protrusions is pressed against the surface of the reinforcing fiber substrate to form a through hole in the reinforcing fiber substrate. be able to.

Further, instead of the pins having the protrusions, a part of the reinforcing fiber yarn can be sublimated by irradiation with laser light to form a space penetrating the reinforcing fiber substrate. Examples of such laser light include a YAG laser, a CO ₂ laser, and the like, but it is preferable to use a YAG laser that can form a space in which reinforcing fiber yarns penetrate even with carbon fibers or glass fibers.

  The method for manufacturing a preform according to the present invention includes forming a preform after bonding reinforcing fiber substrates with a resin material bonded to a reinforcing fiber substrate, or forming a preform with bonding, and reinforcing pins with protrusions. A space penetrating from the surface of the base material and penetrating in the thickness direction of the preform is formed. In addition, a space penetrating the reinforcing fiber base by irradiation with laser light while forming a preform while adhering the reinforcing fiber bases to each other with a resin material adhering to the reinforcing fiber base. To form.

Hereinafter, the present invention will be described in more detail with reference to examples. The raw materials used in the examples and comparative examples are as follows.
-Reinforcing fiber yarn: PAN-based carbon fiber, number of filaments: 24,000, fineness: 1,030 tex, tensile strength: 5830 MPa, tensile elastic modulus: 294 GPa.
Glass fiber yarn: ECE225 1/0 1.0Z, fineness: 22.5 tex, binder “DP” (manufactured by Nittobo).
Polyamide 66 fiber yarn: fineness: 1.7 tex, number of filaments: 7.

Resin material: Polyether sulfone resin (Sumitomo Chemical Co., Ltd. “Sumika Excel” 5003P) 60% by weight (main component) and the following epoxy resin composition 40% by weight (subcomponent) in a twin screw extruder What was melt-kneaded and freeze-ground. Average particle diameter D50 (measured with LMS-24 manufactured by Seishin Enterprise Co., Ltd.) 115 μm, glass transition point 92 ° C.
Epoxy resin composition—21 parts by weight of “Epicoat” 806 manufactured by Japan Epoxy Resin Co., Ltd., 12.5 parts by weight of NC-3000 manufactured by Nippon Kayaku Co., Ltd., and TEPIC-P manufactured by Nissan Chemical Industries, Ltd. 4 parts by weight were stirred at 100 ° C. until uniform.

Matrix resin: An epoxy resin composition obtained by adding 39 parts by weight of the next curing liquid to 100 parts by weight of the next main liquid and stirring uniformly at 80 ° C. Viscosity by E-type viscometer at 80 ° C .: 55 mPa · s, glass transition point after curing at 180 ° C. for 2 hours: 197 ° C., flexural modulus: 3.3 GPa.
Main liquid: As epoxy, 40 parts by weight of “Araldite” MY-721 manufactured by Vantico Co., Ltd., 35 parts by weight of “Epicoat” 825 manufactured by Japan Epoxy Resin Co., Ltd., and 15% by weight of GAN manufactured by Nippon Kayaku Co., Ltd. And 10 parts by weight of “Epicoat” 630 manufactured by Japan Epoxy Resin Co., Ltd., and uniformly dissolved by stirring at 70 ° C. for 1 hour.
Curing solution: 70 parts by weight of “Epicure” W manufactured by Japan Epoxy Resin Co., Ltd., 20 parts by weight of 3,3′diaminodiphenylsulfone manufactured by Mitsui Chemicals Fine Co., Ltd., and “SumiCure” manufactured by Sumitomo Chemical Co., Ltd. 10 parts by weight of S and stirred at 100 ° C. for 1 hour to make it uniform and then cooled to 70 ° C., and as a curing accelerator, 2 parts by weight of Ube Industries, Ltd. t-butylcatechol was further stirred at 70 ° C. for 30 minutes. And uniformly dissolved.

Example 1
FIG. 4 is a schematic perspective view showing an aspect of the reinforcing fiber substrate 10 of Example 1. FIG. Reinforcement fiber yarn warp 11, glass fiber yarn warp auxiliary yarn 12, polyamide 66 fiber yarn weft auxiliary yarn 13, alternate warp yarn 11 and warp auxiliary yarn 12 alternately A unidirectional non-crimp, which is a fabric 14 that is arranged and woven into a weft auxiliary yarn 13 and a plain weave structure, crossing the warp auxiliary yarn 12 and the weft auxiliary yarn 13 and holding the reinforcing fiber yarn 11 integrally. A woven fabric (woven fabric A) was obtained. The fabric A had a fabric thickness of 0.20 mm, a reinforcing fiber basis weight of 193 g / m ² , and a warp (warp auxiliary yarn) density of 1.8 yarns / cm.

On the fabric A, the particulate resin material 15 was freely dropped while being measured with an embossing roller and a doctor blade. At this time, the particles falling under their own weight passed through the vibration net and were uniformly applied to one surface of the fabric. The amount of the particulate particle material applied was 14% by weight of the base material A described later. Furthermore, the hole 16 penetrated in the thickness direction of the reinforcing fiber yarn of the reinforcing fiber base with a pin having projections while adhering the particulate resin material to the woven fabric while heating to 180 to 200 ° C. with a far infrared heater. Then, the substrate was naturally cooled and wound up to obtain a base material A as the reinforcing fiber base material 10. In addition, the outer diameter of the pin having the projection used for forming the through hole 16 was 0.4 mm, and the number of holes per 100 mm ² was set to one.

The obtained base material A has a base material thickness of 0.23 mm, a reinforcing fiber volume ratio Vff obtained from the thickness of the base material A of 46%, a base material basis weight of 225 g / m ² , and a through hole having a hole diameter of 0. The total area of the through holes was 4 mm (area 0.13 mm ² ), 0.13 mm ² per 100 mm ² , and the number of through holes was 1 per 100 mm ² .

  The obtained base material A was laminated in a [−45 ° / 0 ° / + 45 ° / 90 °] laminated structure, and two sets of this laminated structure repeated three times were prepared. They were pasted together to form a mirror-symmetric laminate. Such a laminate (Preform A) was placed in a planar shape and sealed with a sealant and a bag material (polyamide film) to form a cavity provided with a vacuum suction port. The cavity was depressurized from the vacuum suction port to a predetermined vacuum state by a vacuum pump, and the shaping mold was temperature-controlled at 60 ° C. This state was maintained for 2 hours, and after cooling to room temperature, the suction was stopped and the preform A was obtained. Then, this preform A is placed in a flat mold (aluminum), a resin diffusion medium (metal mesh) is placed on the preform, and sealed with a sealant and a bag material. And a cavity provided with a vacuum suction port. The inside of the cavity was decompressed to a predetermined vacuum state from a vacuum suction port by a vacuum pump, and the temperature of the mold and the preform was adjusted to 60 ° C. Next, the matrix resin prepared and vacuum degassed in advance was poured from the resin inlet using atmospheric pressure while maintaining the temperature at 60 ° C. When the matrix resin reached the vacuum suction port, the injection port was closed to stop the injection. Thereafter, the matrix resin was cured by maintaining at 180 ° C. for 2 hours while continuing to reduce the pressure from the reduced pressure suction port, and composite material A was obtained. In the composite material A, the volume fraction Vf of the reinforcing fibers was 55%, no pinholes or voids were found anywhere, and the resin impregnation was good. The resin impregnation time during resin impregnation was also measured. The resin impregnation time was relatively evaluated by an index with the time taken in this example as 1, for comparison with a comparative example described later.

  Furthermore, using the obtained composite material A, CAI at 23 ° C. was measured according to SACMA SRM 2R-94. The impact was obtained by dropping a weight of 5.44 kg (12 pounds) to obtain a weight impact energy of 6.67 kJ / m (270 in · lb).

Example 2
The outer diameter of the pin having the projection used for forming the through hole in Example 1 is 2 mm, and the number of holes per 100 mm ² is set to 2 in the same manner as in Example 1, A reinforcing fiber substrate B was obtained. The obtained base material B has a base material thickness of 0.22 mm, a reinforcing fiber volume fraction Vff determined from the thickness of the base material B of 48%, a base material weight per unit area of 224 g / m ² , and a through-hole diameter of 2 mm ( Area 3.1 mm ² ), the total area of the through holes was 9.4 mm ² per 100 mm ² , and the number of through holes was 3 per 100 mm ² . Further, a preform B was produced in the same manner as in Example 1, and a composite material B was produced by impregnation with a matrix resin. The obtained composite material B had a reinforcing fiber volume fraction Vf of 56%, and the time required for resin impregnation could be impregnated in a short time of 0.7 times that of Example 1.

Example 3
Using a reinforcing fiber base material C in which no through-holes are provided in the reinforcing fiber base material, a multilayer material previously laminated in a [−45 ° / 0 ° / + 45 ° / 90 °] laminated structure and partially bonded is used. A reinforced fiber substrate laminate (Preform C) was produced in the same manner as in Example 1 except that through-holes were formed in the thickness direction of these four layers.

The substrate thickness per substrate C determined from the obtained preform C was 0.23 mm, the reinforcing fiber volume fraction Vff determined from the thickness of the substrate C was 46%, and the substrate basis weight was 225 g / m ^2. Met. Furthermore, resin impregnation was performed to obtain a composite material C. The obtained composite material C was able to impregnate the entire preform with resin. The obtained composite material C had a reinforcing fiber volume fraction Vf of 55%, and the time required for resin impregnation was 0.9 times that of Example 1.

Example 4
Reinforcing fiber substrate laminate in the same manner as in Example 1 except that the reinforcing fiber substrate C in which no through hole was provided in the reinforcing fiber substrate was laminated and the through holes were formed in the thickness direction of the laminate after lamination. (Preform D) was produced.

  The substrate thickness per substrate C determined from the obtained preform D was 0.23 mm, and the reinforcing fiber volume fraction Vff calculated from the thickness of the substrate C was 46%. Furthermore, resin impregnation was performed to obtain a composite material D. The obtained composite material D was able to impregnate the entire preform with resin. The obtained composite material D had a reinforcing fiber volume fraction Vf of 55%, and the time required for resin impregnation was 0.8 times that of Example 1.

Comparative Example 1
A reinforcing fiber substrate C was obtained in the same manner as in Example 1 except that the through hole was not provided in the reinforcing fiber substrate. The obtained base material C had a base material thickness of 0.23 mm, a reinforcing fiber volume fraction Vff determined from the thickness of the base material C of 46%, and a base material weight of 226 g / m ² . Further, a preform E was produced in the same manner as in Example 1, and resin impregnation was performed to obtain a composite material E. The obtained composite material E was able to impregnate the entire preform immediately before the gelation time of the matrix resin. The obtained composite material E had a reinforcing fiber volume fraction Vf of 56%, and although the resin impregnation was good, the time required for resin impregnation was 1.4 times that of Example 1. Table 1 shows the results of Example 1, Example 2, Example 3, Example 4, and Comparative Example 1.

  As is apparent from Table 1, in the composite materials made from the reinforcing fiber bases of Examples 1, 2, 3, and 4 or preforms A to D provided with through holes in the preforms, resin impregnation properties and mechanical properties were obtained. It was possible to make both. On the other hand, the composite material E prepared from the reinforcing fiber base material of Comparative Example 1 and the preform E having no through-holes in the preform is inferior in resin impregnation property but excellent in mechanical properties, and takes a long time for resin impregnation. It cost.

  ADVANTAGE OF THE INVENTION According to this invention, the base material and preform which are excellent in the impregnation property of matrix resin, and can make a dynamic characteristic compatible, and a composite material consisting thereof can be obtained. The composite material thus obtained can be applied to a wide range of fields including structural members such as aircraft and automobiles, but is particularly suitable for aircraft structural members.

It is a perspective view of the reinforced fiber base material concerning one embodiment of the present invention. It is sectional drawing cut | disconnected along the A-A 'line in the extension direction of the reinforced fiber thread | yarn of the reinforced fiber base material of FIG. It is sectional drawing cut | disconnected along the reinforced fiber yarn of the preform which laminated | stacked multiple layers of the reinforced fiber base material which concerns on one embodiment of this invention. It is a perspective view which shows the aspect of the reinforced fiber base material of Example 1 of this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1,10 Reinforcement fiber base material 2,11 Reinforcement fiber yarn 3, which is warp yarn 3,13 Auxiliary fiber 4,14 Reinforcement fiber fabric 5,15 Resin material 6,16 Penetration space (through hole)
7 Preform 12 Warp auxiliary yarn

Claims (19)

  At least a reinforcing fiber base composed of a group of reinforcing fiber threads in which continuous reinforcing fiber yarns are aligned in parallel in one direction, and penetrates the reinforcing fiber yarn in the thickness direction of the reinforcing fiber base. A reinforcing fiber substrate, characterized in that a space is formed.   2. The reinforcing fiber base material according to claim 1, wherein the resin material is adhered to at least one surface of the reinforcing fiber substrate with a gap, and the adhesion amount is 2 to 15% by weight. Reinforced fiber base material.   The reinforcing fiber base material according to claim 1 or 2, wherein the shape of the penetrated space is a line segment or a dot shape when seen in a plan view. Wherein the average area projected in the planar direction of the through-space of the reinforcing fiber base material is 0.1 to 10 mm ^2/1 space, the reinforcing fiber substrate according to any one of claims 1 to 3 . The reinforcing fiber base according to any one of claims 1 to 4, wherein a total area projected in a plane direction of a space through which the reinforcing fiber substrate passes is 0.05 to ⁵ mm ² per 100 mm ^2. Wood. 6. The reinforcing fiber base according to claim 1, wherein the total number projected in the plane direction of the space through which the reinforcing fiber base penetrates is 0.05 to ² per 100 mm ^2. Wood.   The reinforcing fiber base is composed of a reinforcing fiber yarn group extending in one direction and an auxiliary fiber yarn group extending in a direction intersecting the continuous auxiliary fiber yarn with the reinforcing fiber yarn group. The reinforcing fiber substrate according to any one of claims 1 to 6, wherein the reinforcing fiber substrate comprises a directional sheet or a unidirectional woven fabric.   The reinforcing fiber substrate is composed of a bi-directional sheet or a bi-directional woven fabric constituted by crossing or entanglement of reinforcing fiber yarn groups arranged in two directions, according to any one of claims 1 to 6. Reinforced fiber substrate.   The reinforcing fiber substrate according to any one of claims 1 to 8, wherein a yarn width of the reinforcing fiber yarn in the reinforcing fiber substrate is 2 to 10 mm.   The reinforcing fiber base material according to any one of claims 1 to 9, wherein a volume ratio (Vff) of the reinforcing fiber obtained from the thickness of the reinforcing fiber base material is 35 to 65%.   At least two layers of the reinforcing fiber base material according to any one of claims 2 to 10 are laminated, and the laminated reinforcing fiber base materials are at least partially bonded and integrated by a resin material. Preform characterized by being.   At least two layers of reinforcing fiber bases composed of reinforcing fiber yarn groups in which continuous reinforcing fiber yarns are aligned so as to be parallel in one direction are laminated, and at least partially bonded and integrated. A preform, wherein a space penetrating in the thickness direction of the preform is formed at least in the reinforcing fiber yarn in the reinforcing fiber base of the outermost layer. Wherein the average area projected in the planar direction of the through-space of the preform is 0.1 to 10 mm ^2/1 space, preform as claimed in claim 12. The preform according to claim 12 or 13, wherein a total area projected in a plane direction of a space through which the preform passes is 0.05 to ⁵ mm ² per 100 mm ² . The preform according to any one of claims 12 to 14, wherein the total number projected in the plane direction of the space through which the preform passes is 0.05 to ² per 100 mm2.   Reinforced fiber yarn form is formed using reinforcing fiber yarns, and a reinforcing fiber base is formed after bonding or adhering a resin material, and a pin having protrusions is penetrated from the surface of the reinforcing fiber base to strengthen it. A method for producing a reinforced fiber base material, wherein a space penetrating in the thickness direction of the fiber base material is formed.   A space penetrated in the thickness direction of the reinforcing fiber base by irradiation with laser light while forming a reinforcing fiber base using a reinforcing fiber yarn and forming a reinforcing fiber base after bonding or adhering a resin material A method for producing a reinforcing fiber substrate, characterized in that is formed.   After forming the preform while bonding the reinforcing fiber substrates to each other with the resin material bonded to the reinforcing fiber substrate, the pin having the protrusion is penetrated from the surface of the reinforcing fiber substrate, A method for producing a preform, wherein a space penetrating in the thickness direction is formed.   Forming a space penetrating in the thickness direction of the preform by irradiating with laser light while forming the preform after bonding the reinforcing fiber substrates to each other with the resin material bonded to the reinforcing fiber substrate A process for producing a preform, characterized in that

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