JP2005262818A - Reinforcing fiber substrate, preform and method for producing reinforcing fiber substrate - Google Patents

Abstract

Reinforced fiber substrate, preform, and method for producing a reinforced fiber substrate, which not only have excellent handling properties such as form stability but also provide a composite material with high mechanical properties and excellent matrix resin impregnation properties To provide.
A reinforcing fiber base material used for a composite material impregnated with a matrix resin, wherein the reinforcing fiber base material has at least continuous reinforcing fiber yarns arranged in parallel in one direction. Reinforcing fiber comprising a group of reinforcing fiber yarns and having a resin material adhering to at least one surface in a form having a gap in an amount of 2 to 15% by weight, and the substrate has periodic irregularities A base material, a preform using the base material, and a method for producing the reinforcing fiber base material.
[Selection] Figure 1

Description

  The present invention relates to a composite material made of a fiber reinforced plastic (hereinafter sometimes referred to as FRP), a reinforced fiber base material suitable for molding the preform, a preform, and a method for producing the reinforced fiber base material. More specifically, in the production of high-quality composite materials by RTM and VaRTM, which will be described later, the impregnation of the matrix resin is good despite the high fiber volume content (Vf), for example, structures such as aircraft wings and fuselage The present invention relates to a reinforcing fiber base, a preform, and a method for producing a reinforcing fiber base that exhibit excellent mechanical properties (particularly CAI) suitable for the body.

  Conventionally, as a method for producing a composite material such as an aircraft structural member that requires high quality, a prepreg impregnated with a matrix resin in advance on a reinforcing fiber base 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 an autoclave (heating and pressurizing furnace) is often used. This molding method is preferably used because the generation of voids is small even in a composite material, and it is homogeneous and of high quality.

  However, in recent years, without using an autoclave in order to reduce molding and material costs, a reinforced fiber base material in a dry state is set in a cavity formed between an upper die and a lower die, and the clearance is evacuated to reduce the liquid Resin Transfer Molding process (hereinafter referred to as RTM) for injecting the matrix resin, and laminating a reinforcing fiber substrate in a dry state on the mold, covering it with a bag film and evacuating the bag, then the matrix resin An injection molding method such as a so-called vacuum assisted resin transfer molding process (hereinafter referred to as VaRTM) is being applied to aircraft structural members.

  In the above RTM and the like, although the productivity of the composite material is excellent, a low-viscosity resin is used because it is necessary to impregnate the resin in the reinforcing fiber base in a dry state, and the mechanical strength is higher than that of the high-viscosity resin used for the prepreg. There was a problem that it was inferior in a characteristic.

  With respect to such problems, Patent Documents 1 and 2, Non-Patent Documents 1 and 2 and the like describe a technique for arranging a thermoplastic resin layer having a gap between layers of preforms laminated with reinforcing fiber bases, and an epoxy resin and a thermal resin. There has been proposed a technique for improving the mechanical properties (such as delamination resistance and delamination toughness) of a composite material obtained by RTM or the like by applying a resin blended with plastic resin particles onto a fabric.

However, in the above proposal, there is a problem that the impregnation property of the matrix resin is significantly lowered by the thermoplastic resin layer arranged for improving the mechanical characteristics or the resin containing the epoxy resin and the thermoplastic resin particles. As a result, high productivity, which is the original purpose, could not be obtained. That is, the reinforcing fiber base material and the 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 technology that can satisfy such 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

  The 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 reinforcing fiber substrate, a preform, and a method for producing a reinforcing fiber substrate, which are excellent in impregnation of a matrix resin.

  In order to solve the above problems, a reinforcing fiber base material according to the present invention is a reinforcing fiber base material used for a composite material formed by impregnating a reinforcing fiber base material with a matrix resin, and the reinforcing fiber base material is 2 to 15% by weight in the form of at least a reinforcing fiber yarn group in which continuous reinforcing fiber yarns are aligned so as to be parallel in one direction, and the resin material has a gap on at least one surface The reinforcing fiber base material is adhered, and the reinforcing fiber base material has periodic irregularities.

  The preform of the present invention is such that two or more layers of such reinforcing fiber base materials are laminated, and the reinforcing fiber base materials are integrated at least partially by the resin material. It is characterized by being.

  Further, the method for producing a reinforcing fiber base material of the present invention comprises a roller having a concavo-convex pattern on the surface after forming a fabric using reinforcing fiber yarns and bonding or adhering a resin material to the fabric. The method comprises pressing the surface of the material-bonded fabric.

  Or the manufacturing method of the reinforced fiber base material of this invention forms a fabric using a reinforced fiber thread | yarn, resin-bonds the uneven | corrugated sheet | seat which has an uneven | corrugated pattern on the surface, after bonding the resin material to this fabric or bonding. It consists of the method characterized by aligning with material adhesive cloth and pressing with a smooth roller.

  According to the reinforcing fiber base according to the present invention, since the resin material adheres at least on the surface of the reinforcing fiber base with a gap of 2 to 20% by weight and has periodic irregularities, this reinforcing fiber base When a composite material is molded by RTM or VaRTM using a laminate of materials, the handleability is good, the resin impregnation property is excellent, and high mechanical properties (particularly CAI) are 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.

  Furthermore, according to the method for producing a reinforcing fiber base according to the present invention, a roller having a concavo-convex pattern on the surface or a concavo-convex sheet having a concavo-convex pattern is drawn with a resin material adhesive fabric so as to satisfy the requirements of the reinforcing fiber base. In addition, since it is manufactured by pressing with a smooth roller, a composite material having excellent handling properties, high mechanical properties (especially CAI) can be obtained, and good matrix resin impregnation can be achieved.

Hereinafter, preferred embodiments of the reinforcing fiber base according to the present invention will be described with reference to the drawings.
FIG. 1 is a perspective view of a reinforcing fiber base according to an embodiment of the present invention. FIG. 2 is a schematic view of a 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.

  In FIG. 1, the reinforcing fiber base 1 of the present invention has a weft yarn 3 for each of the reinforcing fiber yarns 2 in the orthogonal direction with respect to the reinforcing fiber yarns 2 that become warps oriented in parallel in the longitudinal direction. The cloth is composed of unidirectional woven fabrics 4 alternately arranged one above the other, and the resin material 5 adheres to the entire surface of at least one surface of the cloth with a gap. Furthermore, as shown in FIG. 2, the reinforcing fiber base 1 has periodic recesses 6 and protrusions 7 in the plane direction of the base 1. Further, the convex portion 7 and the concave portion 6 are constituted by the reinforcing fiber yarn 2 and the resin material 5. Moreover, the periodic unevenness | corrugation of this reinforced fiber base material 1 may be a form in which the resin material does not exist in the recessed part 6 of an uneven | corrugated | grooved part as shown in FIG.

  And the resin material has adhered to the fabric surface, and when the reinforcing fiber base material is laminated | stacked and a preform is obtained, the adhesiveness of base materials will be expressed. As a result, misalignment of the reinforcing fiber yarns in the fabric is prevented and the shape stability of the substrate is excellent.

  From the standpoint of mechanical properties, if the resin material is not adhered to at least 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 ( CAI) is inferior. Such a 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), and has a high CAI when the composite material is applied to the structural member. There is a high necessity.

  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 substrates. 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 it is injected into a base material on which the matrix resin is laminated and a composite material is molded. 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.

  This spacer effect also plays a role of concentrating the toughening effect of the resin material between the base materials of the composite material. As a result, an even higher toughening effect is brought about. This is referred to as an interlayer strengthening effect by the resin material.

  The toughening effect, the spacer effect, and the interlayer strengthening effect due to the resin material are even higher when the resin material is unevenly distributed on the substrate surface, particularly when the resin material exists substantially only on the surface of the fabric. Demonstrated in

  In the base material single layer, the resin material may be unevenly distributed and adhered to one surface, or may be unevenly distributed and adhered to both surfaces. 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.

  When the base material is a multilayer, the resin material is placed between each layer of the laminate if it is adhered to both sides only to the substrate located in the center layer of the laminate and only one side is adhered to each other layer. Therefore, 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.

  Moreover, this resin material has periodic unevenness. In other words, since it has periodic irregularities, at least the resin surface between the adjacent layers when the reinforcing fiber substrate is laminated has a recess that regularly becomes a matrix resin flow path. Therefore, the resin can be stably impregnated. Accordingly, the diffusion rate of the matrix resin can be increased even in the in-plane direction between the layers where the matrix resin is difficult to diffuse, and the resin can be impregnated in a short time. In addition, the periodic unevenness | corrugation here means any form as shown in FIGS. 4-7, ie, a convex part is the round shape shown in FIG. 4, the square shape shown in FIG. 5, the rhombus shown in FIG. Any form of the turtle shell shape shown in FIG. Here, in the reinforced fiber base material 10 shown in FIG. 4, the periodic unevenness is formed from a circular convex portion 11 and a concave portion 12 between the convex portions 11. Further, in the reinforcing fiber base 20 shown in FIG. 5, the periodic unevenness is formed from a rectangular convex portion 21 and a concave portion 22 between the convex portions 21. Further, in the reinforcing fiber base 30 shown in FIG. 6, the periodic irregularities are formed from rhombic convex portions 31 and concave portions 32 between the convex portions 31. Further, in the reinforcing fiber base 40 shown in FIG. 7, the periodic unevenness is formed from a turtle shell-shaped convex portion 41 and a concave portion 42 between the convex portions 41.

  If the concave and convex portions are continuous, the continuity of the matrix resin flow path is ensured, so that the matrix resin can be impregnated in a shorter time and the non-impregnated portion is less likely to occur. preferable.

  If the unevenness on the surface of the base material becomes too large, the fluidity of the resin between the layers is improved, but the reinforcing fiber of the adjacent reinforcing fiber base disposed in contact with the uneven surface is bent, and in the composite material Mechanical properties may be reduced. On the other hand, when the resin material is too thin, the fluidity of the resin is lowered, and thus a desired CAI cannot be obtained. From this viewpoint, it is preferable that the maximum height (Rz) of the concavo-convex surface in the reinforcing fiber base is 2 to 100 μm. More preferably, it is 5-70 micrometers, More preferably, it is 8-50 micrometers. Here, the maximum height (Rz) of the uneven surface is a non-contact displacement meter such as a three-dimensional shape measuring instrument using a laser displacement meter (for example, a three-dimensional shape measuring system EMS98-3D manufactured by Sigma Koki Co., Ltd.). Can be measured.

  In addition, if the groove width of the concave portion becomes too large, the fluidity of the resin between the layers is improved, but the reinforcing fibers of the adjacent reinforcing fiber base disposed in contact with the concave and convex surfaces are bent, and the mechanical strength in the composite material is increased. The characteristics may deteriorate. On the other hand, if the groove width becomes too small, the fluidity of the resin is lowered. From this viewpoint, the groove width of the recess is preferably 0.2 to 1 mm. More preferably, it is 0.3-0.5 mm.

  The groove pitch is preferably 3 to 30 mm. If it is less than 3 mm, the number of resin flow paths increases and resin impregnation is facilitated, but the amount of matrix resin between layers increases and Vf of the composite material decreases. On the other hand, if it is larger than 30 mm, the pitch of the grooves becomes too large and the impregnation property of the resin is lowered. Therefore, the groove pitch is preferably 3 to 30 mm.

  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 reinforcing 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.

  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. Examples of the thermosetting resin include an epoxy resin, an unsaturated polyester resin, a vinyl ester resin, and a phenol resin. As thermoplastic resins, polyvinyl acetate, polycarbonate, polyacetal, polyphenylene oxide, polyphenylene sulfide, polyarylate, polyester, polyamideimide, polyimide, polyetherimide, polysulfone, polyethersulfone, polyetheretherketone, Examples thereof include polyaramid, polybenzimidazole, polyethylene, polypropylene, cellulose acetate, and cellulose butyrate.

  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.

  The form of the reinforcing fiber fabric includes a so-called tow sheet in which reinforcing fiber yarns are arranged in one direction, a unidirectional fabric in which reinforcing fiber yarns are arranged in one direction or in two directions, and a bidirectional fabric. . Here, in the tow sheet, in order to improve the resin impregnation property to the base material, it is preferable to arrange the reinforcing fibers so as to ensure an appropriate gap between the strands. Among them, unidirectional fabrics using reinforcing fiber yarns for warp yarns and thin auxiliary yarns for weft yarns have excellent composite properties due to the great straightness of the reinforcing fiber yarns, and the combination of warp yarns and weft yarns. A void portion is formed between the parallel reinforcing fibers, and an appropriate resin path in the thickness direction of the base material can be formed, which is preferable.

  Among these, a unidirectional non-crimp fabric in which the composite material is used for a structural member such as an aircraft 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, fine fibers having a fineness of 50 to 500 dtex are 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 unevenness 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, etc. Organic fiber 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 yarn bundle is elliptical, and the space between the reinforcing fiber yarn bundles arranged in parallel to each other becomes a flow path of the matrix resin in the thickness direction of the reinforcing fiber base material, and the yarn width is large. The pitch between the reinforcing fiber yarn bundles 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, if the yarn width is small, the pitch between the reinforcing fiber yarn bundles is reduced, and the number of resin flow paths in the thickness direction of the base material is increased. Therefore, although the impregnation property of the matrix resin is improved, an elliptical reinforcing fiber bundle is formed. Since the arrangement is made with a small period, the undulation of the reinforcing fiber in the adjacent layer becomes large, and the mechanical properties are deteriorated. 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 reinforced fiber calculated | required from the thickness of the convex part of a reinforced fiber base material is 35 to 55%. More preferably, it is 38 to 53%, and particularly preferably 40 to 53%. Here, the thickness of the reinforcing fiber substrate is a thickness measured according to JIS R7602 (Testing method for carbon fiber fabric), and the thickness when a pressure is applied to 50 kPa 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. The problem is that regarding the laminated structure, if the laminated structure of the base material layer is skewed, only one of the male mold or female mold is used for molding, and a flexible back material is used for the other. Especially manifest. That is, it is not possible to obtain a composite material that has excellent mechanical properties and exhibits a high weight reduction effect.

  On the other hand, if the volume fraction Vff of the reinforcing fibers exceeds 55%, in the case of VaRTM, the reinforcing fibers that are packed too tightly impede the flow of the matrix resin, resulting in poor impregnation and non-impregnated portions (voids). Only a composite material with) is obtained.

  By controlling the volume fraction Vff of the reinforcing fiber in the range of 35 to 55%, the reinforcing fiber volume content Vf and the dimension in the obtained composite material are strictly controlled to a desired range, and high mechanical properties are expressed. It becomes possible to do.

The reinforcing fiber volume fraction Vff calculated from the thickness of the convex portion of the reinforcing fiber base 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 a laminate in which two or more layers of reinforcing fiber bases are laminated, and the reinforcing fiber bases are at least partially bonded and integrated by the resin material. is there. When such adhesion extends over the entire surface of the reinforcing fiber substrate, the handleability of the preform may be inferior or the impregnation property of the matrix resin may be impaired. 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.

  The method for producing a reinforced fiber base material according to the present invention comprises forming a fabric using reinforced fiber yarns, and adding the surface of the reinforced fiber base material with a roller having a concavo-convex pattern on the surface after or after bonding the resin material. Pressure. In another manufacturing method of the present invention, a fabric is formed using reinforced fiber yarns, and after the resin material is bonded or bonded, a concavo-convex sheet having a concavo-convex pattern on the surface is aligned with the reinforced fiber fabric and smoothed. Pressure is applied by a small roller.

  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. Thereafter, a solid resin material is applied or bonded to the reinforcing fiber fabric, and then the resin material is melted and bonded. 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 base, or pressing the surface of the reinforcing fiber base with a roller having a periodic uneven pattern on the surface while bonding the resin material, the unevenness of the roller surface becomes the surface of the reinforcing fiber base. It can be transferred to the resin material adhered to the reinforced fiber base material, and a reinforced fiber base material having periodic unevenness on the surface of the reinforced fiber base material can be obtained. Alternatively, instead of a roller having a periodic unevenness on the surface, an uneven sheet having an uneven pattern on the surface is aligned with the reinforcing fiber fabric and pressed with a smooth roller in the same manner to the surface of the reinforcing fiber substrate. A reinforcing fiber substrate having periodic irregularities can be obtained.

  In addition, the uneven | corrugated sheet | seat which has an uneven | corrugated pattern on the surface has excellent releasability, such as what carried out embossing on the surface, such as a film, a nonwoven fabric, and a mat | matte, and the reinforcing fiber cloth which has a periodic unevenness | corrugation, such as a fluororesin For example, a sheet impregnated with a resin.

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 D ₅₀ (measured with LMS-24 manufactured by Seishin 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., 15 parts 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. 8 is a schematic perspective view showing an aspect of the reinforcing fiber base of Example 1 of the present invention. Reinforcement fiber yarn warp 51, glass fiber yarn warp auxiliary yarn 52, polyamide 66 fiber yarn is weft auxiliary yarn 53, and warp yarn 51 and warp auxiliary yarn 52 alternately. A unidirectional non-crimp, which is a fabric 54 that is arranged and woven into a weft auxiliary yarn 53 and a plain weave structure, crossing the warp auxiliary yarn 52 and the weft auxiliary yarn 53, and holding the reinforcing fiber yarn 51 integrally. A woven fabric (woven fabric A) was obtained. The fabric A had a fabric thickness of 0.2 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 55 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, while heating to 180-200 ° C. with a far-infrared heater, pressing is performed with a metal nip roller (embossing roller) that has been subjected to a release treatment having periodic irregularities on the surface, and the particulate resin material is applied to the fabric A. After bonding, the substrate was naturally cooled and wound up to obtain a substrate A which is a reinforcing fiber substrate 50. The convex shape of the embossing roller is the same circular shape as shown in FIG. 4. The center diameter of the circle is 9 mm, the center distance between the convex portions is 10 mm, the groove width is 0.5 mm, and the depth of the groove portion is It was 40 μm.

The obtained base material A has a base material thickness of 0.234 mm, a reinforcing fiber volume ratio Vff obtained from the thickness of the convex part of the base material A of 46%, a base material weight of 236 g / m ² , and a center-to-center distance between the convex parts: P was 10 mm, groove width: w was 0.45 mm, and the maximum height (Rz) was 40 μm.

  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 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 inside of the cavity was depressurized by a vacuum pump from the vacuum suction port, 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 (made of aluminum), a resin diffusion medium (metal mesh) is placed on the preform, and sealed with a sealant and a bag material. A cavity provided with an inlet and a vacuum suction port was formed. The inside of the cavity was evacuated to a vacuum 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 100 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).

Comparative Example 1
As Comparative Example 1, a reinforced fiber base material B was obtained by using a unidirectional non-crimp fabric as it was in the same manner as in Example 1 except that no resin material was used. In the obtained base material B, since the resin material did not adhere, the periodic unevenness | corrugation of the base-material surface did not exist. In addition, the obtained base material B has a base material thickness of 0.201 mm, a reinforcing fiber volume ratio Vff obtained from the thickness of the convex portion of the base material B of 54%, a base material weight of 193 g / m ² , and a maximum height (Rz ) Was 150 μm. Further, a preform B was produced in the same manner as in Example 1, and resin impregnation was performed to obtain a composite material B. The obtained composite material B did not reach the entire preform with resin impregnation even after the gelling time of the matrix resin had elapsed, and became a composite material without resin impregnation. For this reason, CAI could not be evaluated.

Comparative Example 2
As Comparative Example 2, a reinforcing fiber substrate C was obtained in the same manner as in Example 1 except that a metal nip roller having a smooth surface was used without using an embossing roller. Since the obtained base material C was nipped while being pressed with a smooth metal roll, there was no periodic unevenness on the base material surface. In addition, the obtained base material C has a base material thickness of 0.225 mm, a reinforcing fiber volume ratio Vff obtained from the thickness of the convex portion of the base material A is 48%, a base material weight is 236 g / m ² , and a maximum height (Rz ) Was 14 μm. Further, a preform C was produced in the same manner as in Example 1, and a composite material C was produced by impregnation with a matrix resin. The obtained composite material C had a reinforcing fiber volume fraction Vf of 56%, and although the resin impregnation was good, the time required for resin impregnation was 1.45 times that of Example 1. The results of Example 1 and Comparative Examples 1 and 2 are shown in Table 1.

  As is apparent from Table 1, the base material A of Example 1 and the base material C of Comparative Example 2 have morphological stability that does not cause misalignment or meandering of the fabric due to the resin material adhered on the fabric. Moreover, when these were preformed, excellent tackiness was expressed. Regarding the resin impregnation property, the base material A could be impregnated with the matrix resin in a shorter time than the base material B (not impregnated) and the base material C. From the above results, the effect of the present invention is clear.

  According to the present invention, it is possible to obtain a base material and a preform which are not only excellent in handleability but also excellent in the impregnation property of a matrix resin, and a composite material composed thereof. 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 the elements on larger scale of the uneven | corrugated | grooved part cut | disconnected along the reinforced fiber yarn of the reinforced fiber base material of FIG. It is a partial expanded sectional view of the uneven | corrugated | grooved part cut | disconnected along the reinforced fiber yarn of the reinforced fiber base material which concerns on another embodiment of this invention. It is a plane schematic diagram which shows one aspect | mode of the surface unevenness | corrugation of the resin material in this invention. It is a plane schematic diagram which shows another aspect of the surface unevenness | corrugation of the resin material in this invention. It is a plane schematic diagram which shows another aspect of the surface unevenness | corrugation of the resin material in this invention. It is a plane schematic diagram which shows another aspect of the surface unevenness | corrugation of the resin material in 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

1 Reinforcing fiber substrate 2 Reinforcing fiber (warp yarn)
DESCRIPTION OF SYMBOLS 3 Weft thread 4 Reinforcement fiber cloth 5 Resin material 6 Recessed part of reinforcing fiber base surface 7 Convex part of reinforcing fiber base surface 10, 20, 30, 40 Reinforcing fiber base material 11, 21, 31, 41 Convex part 12, 22, 32, 42 Concave part on the surface of reinforcing fiber base 50 Reinforcing fiber base material 51 Reinforcing fiber 52 Warp auxiliary yarn 53 Weft auxiliary yarn 54 Reinforcing fiber fabric 55 Resin material

Claims (13)

  A reinforcing fiber base material used for a composite material formed by impregnating a matrix resin into a reinforcing fiber base material, wherein the reinforcing fiber base material pulls at least continuous reinforcing fiber yarns in parallel in one direction. It is composed of a group of reinforcing fiber yarns that are aligned, and the resin material adheres in a form having a gap on at least one surface, and the reinforcing fiber substrate has periodic irregularities. A reinforcing fiber substrate characterized by the above.   The reinforcing fiber base material according to claim 1, wherein the concave and convex portions of the periodic unevenness of the reinforcing fiber base material are continuous in the plane direction of the reinforcing fiber base material.   The reinforcing fiber substrate according to claim 1, wherein the resin material has periodic irregularities, and the concave portions of the periodic irregularities are continuous in the plane direction of the reinforcing fiber substrate.   The unidirectional sheet in which the reinforcing fiber base is composed of reinforcing fiber yarn groups and a weft-direction auxiliary fiber yarn group extending in a direction intersecting the continuous auxiliary fiber yarns with the reinforcing fiber yarn groups. The reinforcing fiber substrate according to any one of claims 1 to 3, wherein   The reinforcing fiber substrate according to claim 4, wherein the unidirectional sheet is a woven fabric.   The reinforcing fiber substrate has a reinforcing fiber yarn group and a warp direction auxiliary fiber yarn group extending in a direction parallel to the reinforcing fiber yarn, and the side direction auxiliary fiber yarns are formed on both sides of the base material. A unidirectional non-crimp woven fabric in which a woven structure is formed from a group of auxiliary fibers and a supplementary fiber yarn constituting a warp direction auxiliary fiber yarn group. The reinforcing fiber base material according to any one of claims 1 to 3.   The reinforcing fiber substrate according to any one of claims 4 to 6, wherein the weft direction auxiliary fiber yarn has a single yarn diameter of 10 to 100 µm and a twist number of 50 turns / m or less.   The reinforcing fiber substrate according to any one of claims 1 to 7, wherein the reinforcing fiber yarn has a yarn width of 2 to 10 mm in the reinforcing fiber substrate.   The reinforcing fiber base material according to any one of claims 1 to 8, wherein the volume ratio (Vff) of the reinforcing fiber obtained from the thickness of the convex portion of the base material is 35 to 55%.   The reinforced fiber base material according to any one of claims 1 to 9, wherein the maximum height (Rz) of the uneven surface formed by the resin material is 2 to 100 µm.   The reinforcing fiber base material according to any one of claims 1 to 10, wherein at least two layers are laminated, and the reinforcing fiber base materials are at least partially bonded and integrated by the resin material. A featured preform.   A fabric is formed using reinforcing fiber yarns, and the surface of the resin material-bonded fabric is pressurized with a roller having a concavo-convex pattern on the surface after or while bonding the resin material to the fabric. A method for producing a reinforcing fiber substrate.   After forming a fabric using reinforced fiber yarns and bonding or adhering a resin material to the fabric, aligning an uneven sheet having an uneven pattern on the surface with the resin material bonded fabric and applying it with a smooth roller A method for producing a reinforced fiber base material, comprising pressing.

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