JP2009249754A - Reinforcing fiber woven fabric and method for weaving the same - Google Patents

Abstract

An object of the present invention is to provide a unidirectional strengthening that is not limited to the materials of warps and weft assist yarns, does not cause point-like irregularities on the surface of a woven fabric after weaving, and that the shape is ensured from the time of weaving and has excellent resin impregnation properties. Provided is a method of weaving a unidirectional reinforcing fiber woven fabric that can achieve high production efficiency with a slight modification to the fiber woven fabric and the conventional loom.
A unidirectional reinforcing fiber fabric comprising a plurality of weft reinforcing yarns 2 and warp reinforcing yarns 3 arranged in parallel between one or more warp groups 1 at a predetermined interval. . A plurality of the warp groups 1 are arranged in a sheet shape on the same plane without bending, and the weft reinforcing yarns 2 are alternately arranged along the front and back surfaces of the sheet-like warp group. 2 and warp reinforcing yarn 3 form a woven structure and are woven together with warp group 1. Each yarn unit of the weft reinforcing yarn 2 is also made of a flat yarn made of reinforcing fiber multifilament yarn, and the weft reinforcing yarn 2 is made of an aligned yarn of two flat yarns.
[Selection] Figure 1

Description

  The present invention is applied to various fields such as general structures, automobiles, leisure / sports equipment, aerospace equipment, etc. and for reinforcement of elevated road piers, floor slabs, building columns, walls, etc. The present invention relates to a unidirectional reinforcing fiber woven fabric that exhibits excellent properties as a reinforcing base material for applied fiber reinforced plastic (FRP) and a method for producing the same.

  As the reinforcing base material for FRP, fabrics made of high strength and high elastic modulus fibers such as inorganic fibers such as glass fibers and carbon fibers, and organic fibers such as aramid fibers and high strength polyethylene fibers are frequently used.

  In general, FRP has large anisotropy and exhibits high tensile strength and elastic modulus in the direction in which the reinforcing fibers are oriented, but has a defect that it can exhibit almost only the strength of the resin in the direction perpendicular to the fibers. Therefore, when high tensile strength and elastic modulus are required in multiple directions, it is preferable to orient a large number of reinforcing fibers in the required directions. In other words, in order to ensure high tensile strength and elastic modulus in multiple directions, and to ensure ease of subsequent handling, the reinforcing fibers are reinforced so that they are oriented in the warp direction, the weft direction, and at an oblique angle with a desired angle. If fibers are arranged, more effective reinforcement is possible.

  In order to orient the fibers in multiple directions in this way, cut the sheets with the fibers facing in one direction into a desired size, prepare multiple sheets, and stack the sheets while directing the fibers in the required direction. Impregnated with matrix resin. This lamination operation is not only complicated, but it requires considerable skill to handle the sheet while ensuring the fiber direction of each sheet.

  Therefore, conventionally, a reinforcing fiber fabric in which reinforcing fiber yarns are arranged in the warp direction and the weft direction is used. In this reinforcing fiber fabric, since the warp and the weft intersect, the thickness of the fiber increases at the intersection of the warp and the weft, and irregularities are generated on the surface of the woven reinforcing fiber fabric. The generation of the irregularities refuses to uniformly impregnate the matrix resin, and when an external force is applied to the fabric, stress is concentrated at the crossing portion, and the strength characteristic as FRP tends to be non-uniform.

  Therefore, in order to reduce the number of intersections between the warp and the weft auxiliary yarn as much as possible, to reduce the crimp of the warp and to ensure the stability of the fabric form, a plurality of flat warps composed of multifilaments are possible. A so-called unidirectional reinforcing fiber fabric in which weft auxiliary yarns are woven in such a manner that they are arranged in parallel as closely as possible and the weft auxiliary yarns are woven so as to intersect with the warp yarns with the interval between the weft auxiliary yarns being larger than the warp interval is, for example, Japanese Patent No. 3279049 Japanese Patent Laid-Open No. 11-43839 (Patent Document 2) and the like have been proposed.

  Patent Document 1 discloses a reinforced fiber multifilament yarn on both sides of a sheet surface of a yarn group in which flat reinforcing fiber multifilament yarns that do not have a bend in which stress is concentrated are aligned in one direction and parallel to each other in a sheet shape. Crossing weft-direction auxiliary yarn groups are located, and the weft-direction auxiliary yarn groups and warp-direction auxiliary yarn groups parallel to the reinforcing fiber multifilament yarns are integrally held as a flat reinforcing fiber multifilament yarn group. A directionally reinforced fabric is disclosed. The reinforcing fiber multifilament yarn has a fineness of 7,200 to 20,000 denier, a converging property in a range of 100 to 1,000 mm as a hook drop value, and a yarn width / yarn thickness ratio of 30 or more. The warp direction auxiliary yarn group and / or the weft direction auxiliary yarn group include a low melting point polymer, and the intersection of the warp direction auxiliary yarn group and the weft direction auxiliary yarn group is bonded to each other by the polymer.

  By adopting such a configuration, even a reinforcing fiber multifilament yarn having a high fineness is oriented straight in a predetermined direction, and the reinforcing fiber multifilament yarn does not converge due to tightening of the weft direction auxiliary yarn and is uniformly high Since it is dispersed at a density, the high tensile strength and elastic modulus of the reinforcing fiber are sufficiently exhibited.

Patent Document 2 is a unidirectional fabric in which a large number of reinforcing fiber yarns are arranged in parallel in the warp direction and auxiliary yarns are arranged in the weft direction. The auxiliary yarn has a flexural rigidity index (tensile modulus of fiber × (diameter of single fiber) ⁴ × number of filaments) of 5 × 10 ⁻³ to 200 × 10 ⁻³ Kgf / · mm ² , and a reinforcing fiber yarn in the warp direction It is assumed that the ratio of the tensile rigidity (stretch modulus of fiber x fiber cross-sectional area per unit width) of the strip and the weft direction auxiliary yarn is 3 to 100. The invention described in Patent Document 2 is particularly excellent in dimensional stability and handleability, has good matrix resin impregnation properties when molded into a fiber-reinforced plastic, and does not cause wrinkles or blisters. Is able to perform smooth molding.
Japanese Patent No. 3279049 JP 11-43839 A

  According to the unidirectional reinforcing fiber fabrics described in Patent Documents 1 and 2, since many flat reinforcing fiber multifilament yarns are not bent and are not easily converged by the weft direction auxiliary yarn, for example, a structure It is said that an FRP having improved adhesion during repair and reinforcement and having a smooth surface during molding can be obtained. By the way, in the weaving method of the unidirectional reinforcing fiber fabric disclosed in FIG. 6 of Patent Document 1, the reinforcing fiber multifilament yarn and the warp direction auxiliary yarn are respectively passed through the reeds and the reeds are driven to drive the reinforced fiber multifilaments. Filament yarns and warp direction auxiliary yarns are alternately raised and lowered to form an opening, and weft direction auxiliary yarns are sequentially inserted into the opening to be beaten to produce a woven fabric. Here, in the woven fabric that has been woven, the weft direction auxiliary yarn is assumed to maintain a linear shape.

  However, in the weaving method described in Patent Document 1, bending (crimping) usually occurs at the intersection of the reinforcing fiber multifilament yarn as the warp and the weft direction auxiliary yarn. In order to keep the weft direction auxiliary yarn linearly even after weaving, the weft direction auxiliary yarn must have a tensile rigidity greater than that of the reinforcing fiber multifilament yarn, and its form can be twisted yarn or It is necessary to use a bundled yarn or make the weft direction auxiliary yarn more rigid than the reinforcing fiber multifilament yarn. On the other hand, in order to weave the reinforcing fiber multifilament yarn in a straight line (on the same plane) by the above-described weaving method, it is necessary to make the tensile stiffness of the reinforcing fiber multifilament yarn larger than the tensile stiffness of the weft direction auxiliary yarn.

  However, although Patent Document 1 describes the tensile rigidity of the flat reinforcing fiber multifilament yarn, the rigidity of the weft direction auxiliary yarn is higher than that of the reinforcing fiber multifilament yarn which is a warp as described above. It is only desirable to do. Moreover, as long as the weft-direction auxiliary yarn is woven in a straight line, it is inevitable that the reinforcing fiber multifilament yarn, which is a warp, bends at the intersection with the weft-direction auxiliary yarn.

  Incidentally, in the unidirectional reinforcing fiber woven fabric of Patent Document 2, unlike Patent Document 1, there is no warp direction auxiliary yarn, but the tensile stiffness of the warp yarn composed of multifilaments of reinforcing fibers and the weft direction assist. The ratio of the tensile stiffness of the yarn is 3 to 100, and the tensile stiffness of the warp direction auxiliary yarn is larger than the tensile stiffness of the weft direction auxiliary yarn. Not only depending on this factor, but by setting the tensile stiffness as described above, in the unidirectional reinforcing fiber fabric obtained by a normal weaving method, the warp-direction reinforcing fiber multifilament yarn group is coplanar. It is arranged on the top.

  As described above, the unidirectional reinforcing fiber fabrics described in Patent Documents 1 and 2 are manufactured by paying attention to the physical properties of the warp direction reinforcing fiber multifilament yarn group and the weft direction auxiliary yarn, and the weaving thereof. The method is not different from the conventional method. Even if it is slight, crimp occurs in the warp-direction reinforcing fiber multifilament yarn group, and bending occurs at the intersection of the reinforcing fiber multifilament yarn and the weft-direction auxiliary yarn. Unevenness is inevitable.

  The present invention has been developed in view of such a conventional situation, and is not limited to the materials of the warp and the weft auxiliary yarn, does not cause point-like unevenness on the surface of the woven fabric, and the form thereof is woven. Providing a unidirectional reinforcing fiber woven fabric secured from time and excellent in resin impregnation, and a method of weaving the unidirectional reinforcing fiber woven fabric, which can achieve high production efficiency by adding a slight improvement to a conventional loom. The purpose is to do.

  The above object is a basic configuration of the unidirectional reinforcing fiber fabric according to the present invention, and a plurality of flat warp yarns made of reinforcing fiber multifilament yarns are aligned in one direction and arranged in parallel. And unidirectional reinforcement comprising a plurality of weft reinforcing yarns arranged to intersect with the warp yarn groups and warp reinforcing yarns arranged in parallel between one or more warp yarn groups at a required interval It is a textile fabric, and a plurality of the warp groups are arranged in a sheet shape on the same plane without bending, and weft reinforcement yarns are alternately arranged along the front and back surfaces of the sheet-like warp groups The weft reinforcing yarn and the warp reinforcing yarn are woven in a woven structure, each unit of the weft reinforcing yarn is composed of a flat yarn made of reinforcing fiber multifilament yarn, and the two weft reinforcing yarns Unidirectional reinforcing fiber fabric, which is an aligned yarn of flat yarns It is achieved.

  According to a preferred aspect of the invention, at least one of the weft reinforcing yarn and the warp reinforcing yarn contains a low-melting polymer, the warp reinforcing yarn is arranged adjacent to each warp group, and the warp reinforcing yarn is disposed on the sheet surface. It is preferable that the weft reinforcement yarns arranged on the front and back are alternately crossed so that the weft reinforcement yarns extend substantially linearly. The reinforcing fiber multifilament yarn constituting the warp and weft is preferably a multifilament yarn having substantially no twist, and the materials of the warp reinforcement yarn and the weft reinforcement yarn are carbon fiber yarn, glass fiber yarn, polyaramid It can be selected from fiber yarn, vinylon fiber yarn and polyester fiber yarn.

  The basic structure of the weaving method according to the present invention for weaving a unidirectional reinforcing fiber woven fabric having the above-described structure is to supply a plurality of warp groups arranged in parallel before bending, To move the warp reinforcing yarn up and down to form an opening based on the fabric structure of the weft reinforcing yarn between the warp reinforcing yarn arranged between the warp groups and the warp group, Including two weft reinforcing yarns inserted into an opening formed between the warp reinforcing yarns and inserting the weft reinforcing yarns every time the weft reinforcing yarns are inserted. The present invention is characterized in that the weft reinforcing yarns are alternately inserted through the front surface side opening and the back surface side opening among the openings formed across the front and back surfaces of the sheet surface.

  According to a preferred aspect, the weaving is performed using a needle loom, and the switching operation is performed immediately before the opening of the weft reinforcement thread of the needle loom at the needle closing position immediately before the opening after the beating operation is closed. At the timing before insertion, switching is made between the first insertion position of the opening portion on the front surface side of the sheet surface and the second insertion position of the opening portion on the back surface side.

  According to the unidirectional reinforcing fabric of the present invention and the method for producing the same, the warp group composed of flat multifilaments arranged in parallel at the time of being on the loom is always folded without being bent at all. The straight line state is maintained, and each warp group is already in the same plane at the time of weaving and is in the form of a sheet, and the weft reinforcement yarn is a warp reinforcement yarn and a linearly extending sheet-like warp group. Therefore, only the external force at the time of hammering acts on the weft reinforcing yarn. For example, the external force at the time of hammering may impair the flat cross-sectional shape of the weft reinforcing yarn, for example, by referring to the hammering timing disclosed in Japanese Patent Application Laid-Open No. 2003-268650 previously proposed by the present applicant. Absent.

  That is, immediately before the opening is closed and before the next weft insertion, the first insertion position of the front surface side opening portion and the second insertion position of the rear surface side opening portion of the sheet surface are switched to each insertion position. After the weft reinforcing yarns are sequentially inserted into the corresponding openings, the beating is performed when the insertion is completed and the opening formed with the warp group is to be closed. In this way, the flattened form of the weft reinforcement yarn is broken in order to press the weft reinforcement yarn composed of flat multifilaments against the sheet surface of the warp group where the warp reinforcement yarn is in the fixed position. It will be possible to beat.

  The unit of the weft reinforcing yarn is composed of two flat multifilament yarns that are aligned. Therefore, when the thickness of the weft reinforcement yarn itself is small and the weft reinforcement yarn is linearly arranged on both the front and back surfaces of a plurality of sheet-like warp groups, crimps can be generated only on the warp reinforcement yarn, and as a whole fabric The flatness without unevenness is ensured. In addition, since two flat multifilament yarns which are weft reinforcing yarns are inserted in parallel, if the timing of beating is appropriate, the weft reinforcing yarns are not bound and the flat shape is maintained. . In addition, when a needle loom is used to manufacture the unidirectional reinforcing fiber fabric of the present invention, two weft reinforcing yarns are inserted into one opening by the reciprocating movement of the needle. Compared to conventional ordinary looms and rapier looms, the number of times can be relatively delayed by more than twice, and not only the timing control is easy, but also the weaving efficiency is further improved.

  The operation of inserting the weft reinforcement thread into the opening is, for example, such that the needle is inserted alternately into the opening part on the front side and the opening part on the back side of the sheet-like warp group among the openings formed by the warp reinforcement thread. The operation start position is automatically switched to the vertical position with respect to the sheet surface in the preferred mode as described in the solving means of the invention.

Hereinafter, typical embodiments of the present invention will be specifically described with reference to the drawings.
FIG. 1 shows a unidirectional reinforcing fiber fabric according to an embodiment of the present invention. In FIG. 1, reference numeral 1 denotes a warp group consisting of flat reinforcing fiber multifilament yarns that are substantially untwisted. One unit. In the unidirectional reinforcing fiber fabric in the present embodiment, a plurality of warp groups 1 are arranged in parallel in one direction, and the warp groups 1 are arranged in a sheet on the same plane. It does not substantially have a bent portion where stress is concentrated. For this reason, the weft reinforcing yarns 2 are arranged alternately along the front and back surfaces of the plurality of warp groups 1 in a direction orthogonal to the warp groups 1.

  The unidirectional reinforcing fiber fabric according to the present embodiment includes a plurality of warp groups 1 and weft reinforcement yarns 2 described above, and a warp reinforcement in parallel with the warp group 1 between the adjacent warp groups 1. Thread 3 is arranged. The warp reinforcing yarns 3 are alternately arranged on the front and back surfaces of the weft reinforcing yarns 2 linearly arranged along the front and back of the sheet surface of the warp group 1 and at a predetermined interval in the length direction of the sheet surface. The weft reinforcing yarns 2 are alternately crossed while being bent up and down. The woven structure between the weft reinforcing yarn 2 and the warp reinforcing yarn 3 can be various woven structures such as a twill structure other than the plain weave structure described above.

  The number of filaments of the reinforcing fiber multifilament constituting the warp group 1 depends on the type of reinforcing fiber, but 1,000 to 50,000 carbon fibers and 5 to 10 μm in filament diameter are common. is there. The type of the reinforcing fiber may be either an inorganic fiber or an organic fiber. In addition to natural or synthetic polymer fibers, carbon fibers, glass fibers, aromatic aramid fibers, aromatic polyaramid fibers, boron fibers. In addition, alumina fibers and silicon carbide fibers may be used alone or in combination of two or more. The material of the warp reinforcing yarn 3 is the same as that of the reinforcing fiber, but the yarn form is preferably a twisted yarn rather than an untwisted multifilament, or may be a normal spun yarn.

  For cost reasons, carbon fibers are often used as the reinforcing fibers for composite materials, and in particular, those having 1,000 to 50,000 filaments per multifilament are widely used.

  The sizing agent used for the reinforcing fiber multifilament may be either an inorganic substance or an organic substance, and commercially available ones can be used. In particular, as a sizing agent for carbon fiber multifilaments, epoxy resins, urethane resins, polyester resins, bismaleimide resins, imide resins, nylon resins and the like are often used alone or in combination of two or more. In particular, when an epoxy resin and a urethane resin are used singly or in combination of two or more kinds, a carbon fiber multifilament having good multifilament opening and spreading at the time of processing is obtained. The adhesion amount of the sizing agent is preferably 10% by weight or less with respect to the reinforcing fiber.

  The form of the reinforcing fiber is slightly influenced by the entanglement of the filaments in the reinforcing fiber multifilament, the twisted state of the multifilament, or flattening of the multifilament when winding on the bobbin. The smaller the number of filaments, the larger the spreading width per filament and the less the entanglement between filaments tends to be. Accordingly, the spreadability of the multifilaments during the production of the prepreg is improved, and a prepreg excellent in resin impregnation is often obtained.

  As shown in FIG. 1, the unidirectional reinforcing fiber fabric according to this embodiment uses the reinforcing fiber multifilament as described above as the warp group 1 and the weft reinforcing yarn 2, and the two weft reinforcing yarns 2 are aligned. The weft reinforcing yarns 2 are arranged so as to intersect the warp yarn groups 1 with an interval between the front and back of the sheet surface of the warp yarn groups 1 arranged in parallel. Furthermore, in the unidirectional reinforcing fiber woven fabric according to the present invention, warp reinforcing yarns 3 are arranged in parallel with the warp yarns between one or more warp yarn groups 1, and the warp reinforcing yarns 3 are arranged in the warp yarn groups. 1 after straddling the upper surface of the weft reinforcement yarn 2 arranged on the surface of the sheet surface 1 and then straddling the lower surface of the weft reinforcement yarn 2 arranged on the back surface of the sheet surface, This is repeated across the top surface of the. In this embodiment, the weft reinforcing yarn 2 and the warp reinforcing yarn 3 are woven with a plain weave structure. The basis weight of the woven fabric is set to an appropriate basis weight depending on the type of reinforcing fiber multifilament used.

  Next, the manufacturing method of the unidirectional reinforcing fiber fabric of the present invention using the warp 1, the weft reinforcing yarn 2, and the warp reinforcing yarn 3 as described above will be specifically described based on FIG. 2 and FIG. The warp group 1 of the reinforcing fiber multifilament is taken from a large number of bobbins (not shown) set on a needle loom and is straightened without being bent to the pre-weaving 4 via a tension adjusting device (not shown). Are supplied in parallel on the same plane. At this time, in the illustrated example, a plurality of warp reinforcing yarns 3a, 3b are alternately passed through the two front and rear heels 5a, 5b in the weaving width direction, and one or more warp groups are arranged in parallel by driving the heels 5a, 5b. 1 is arranged so that it can move up and down. A wing 6 that reciprocates in the front-rear direction is disposed between the heel 5a in front of the weaving direction and the front 4 of the weave. The wings 6 are formed with ridges through which a plurality of warp groups 1 can be inserted in the order of arrangement, and ridges through which the warp reinforcing yarns 3 arranged between one or more warp groups 1 can be inserted. Yes. The arrangement of the meshes of the reeds 5a, 5b and the reed wings 6 is determined by the woven structure between the weft reinforcing yarn 2 and the warp reinforcing yarn 3, and is not limited to the illustrated embodiment.

  On the other hand, the weft insertion of the weft reinforcing yarn 2 is performed by reciprocating in the opening along one opening formed between the warp yarns. Therefore, if the needle loom is used, the weft reinforcing yarn 2 is necessarily composed of two aligned yarns, and is continuously formed at the folded end of the weft reinforcing yarn 2 each time the weft is inserted. Stitches are made and ears are formed at the folded ends.

  The unidirectional fiber reinforced fabric produced by the present invention is composed of a sheet surface in which a plurality of flat warp groups 1 made of multifilaments are arranged on the same plane, and the at least one warp group 1 It is obtained by weaving with a predetermined woven structure between the warp reinforcing yarns 3 arranged between them and the weft reinforcing yarns 2 arranged alternately and linearly on the front and back surfaces of the sheet surface. That is, at the time of weft insertion, the weft reinforcing yarns 2 must be alternately wefted on the front and back surfaces of the sheet surface formed by a plurality of flat warp groups 1.

  In order to alternately weft the weft reinforcing yarns 2 along the front and back surfaces of the warp sheet surface formed on the same plane in which a plurality of flat warp groups 1 extend linearly, for example, as shown in FIGS. In this way, an opening is formed between the warp reinforcing yarn 3 and the sheet surface, and after weft insertion into the opening above the sheet surface, the next weft insertion into the opening below the sheet surface to be formed next time There must be. However, in the present invention, the plurality of flat warp groups 1 supplied in parallel on the loom also advance on the same plane without bending up to the front 4 as described above. For this reason, it is necessary to alternately form openings formed between the warp group 1 and the warp reinforcing yarn 2 at least above and below the sheet surface of the warp group 1 every time weft insertion.

  In order to alternately insert the wefts in the openings formed on the front and back sides with the sheet surface interposed therebetween, the weft insertion position (weft insertion position) must be switched up and down with the sheet surface interposed therebetween. Therefore, in the present invention, although not shown in the drawings, the rotation base end position of the swing arm that supports the base end of the needle is changed up and down by means of, for example, a crank mechanism, a cam mechanism, or an electronic control mechanism. It has. By using the needle loom having such a configuration, the unidirectional fiber reinforced fabric of the present invention can be easily woven.

  In the present invention, the constituent yarns of the weft reinforcing yarn 2 are also composed of flat fiber yarns made of multifilaments as in the warp group 1, and these two flat fiber yarns are aligned to serve as weft reinforcing yarns. Yes. When the flat weft reinforcing yarns 2 are wefted in a state in which the two flat weft reinforcing yarns are aligned and then beaten, the two yarns are crushed and bound by the force of the beating. Therefore, it is important to avoid this binding and weave the two flat yarns while maintaining the shape. Therefore, in this embodiment, the warp reinforcing yarn 3 and the size of the opening of the opening and the size of the opening of the opening disclosed in Japanese Patent Application Laid-Open No. 2003-268650 previously proposed by the present applicant are referred to Strike is performed immediately before the opening between the warp group 1 and the opening is as small as possible. A strike is made at this timing.

  When beating is performed at such timing, the weft reinforcement yarn 2 is pressed against the sheet surface of the warp group 1 by the warp reinforcement yarn 3 which is closing, and conversely, the flat state is promoted and the aligned 2 The flat yarns of the books are maintained in parallel without overlapping in the yarn width direction. Here, if the tension of the warp reinforcing yarn 3 is appropriately adjusted, the weft insertion is completed while maintaining the substantially straight state without largely bending the weft reinforcing yarn 2.

It is a fragmentary perspective view which shows the schematic block diagram of the conventional reinforced fiber fabric. It is explanatory drawing which shows the weft strike state when opening is formed between the warp reinforcement yarn above the warp group. It is explanatory drawing which shows the weft strike state when opening is formed between the warp reinforcement yarn under the warp group.

Explanation of symbols

1 Warp group (warp)
2 Weft reinforcement thread 3 Warp reinforcement thread 4 Weaving front 5a, 5b

Claims (8)

A flat warp group in which a plurality of warp yarns made of reinforcing multifilament yarns are aligned in one direction and arranged in parallel, a plurality of weft reinforcement yarns arranged to intersect the warp group, and A unidirectional reinforcing fiber fabric comprising warp reinforcing yarns arranged in parallel between one or more warp groups at intervals,
The plurality of warp groups are aligned in a sheet on the same plane without bending,
The weft reinforcing yarns are alternately arranged along the front and back surfaces of the sheet-like warp group, and the weft reinforcing yarns and the warp reinforcing yarns are woven into a woven structure,
Each yarn unit of the weft reinforcing yarn is composed of a flat yarn made of reinforcing fiber multifilament yarn, and the weft reinforcing yarn is an alignment yarn of two flat yarns,
Unidirectional reinforcing fiber fabric.   The reinforcing fiber fabric according to claim 1, wherein at least one of the weft reinforcing yarn and the warp reinforcing yarn comprises a low melting point polymer.   The warp reinforcing yarns are arranged adjacent to each other for each warp group, the warp reinforcing yarns alternately intersect with the weft reinforcing yarns arranged on the front and back of the sheet surface, and the weft reinforcing yarns extend substantially straight. Item 10. A reinforcing fiber fabric according to Item 1.   The reinforcing fiber woven fabric according to claim 1, wherein the reinforcing fiber multifilament yarn constituting the warp and weft reinforcing yarn is a multifilament yarn having substantially no twist.   The reinforcing fiber fabric according to claim 1, wherein the warp reinforcing yarn and the weft reinforcing yarn are selected from carbon fiber yarn, glass fiber yarn, polyaramid fiber yarn, vinylon fiber yarn, and polyester fiber yarn. A method for weaving a reinforcing fiber fabric according to any one of claims 1 to 5,
Supplying a plurality of warp groups arranged in parallel straight before weaving without bending,
Forming an opening based on the fabric structure of the weft reinforcement yarn between the warp reinforcement yarn and the warp yarn group arranged between the warp yarn groups by moving the warp reinforcement yarn up and down by driving the reed,
Pulling and inserting two weft reinforcement yarns into the opening formed between the warp group and the warp reinforcement yarns, and striking each time the weft reinforcement yarns are inserted,
Comprising
The weft reinforcing yarns are alternately inserted through the front surface side opening and the back surface side opening among the openings formed across the front and back surfaces of the sheet surface composed of a plurality of warp groups,
Weaving method for reinforcing fiber fabric.   The weaving method according to claim 6, comprising performing weaving using a needle loom.   The weft reinforcing thread insertion position of the needle is just before the opening after the beating is closed and before the next weft insertion, and the first insertion position of the front surface side opening portion of the seat surface and the first opening position of the back surface side opening portion. The weaving method according to claim 6 or 7, comprising switching between two insertion positions.

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