JPH08337666A - Preform and its production - Google Patents

Abstract

PURPOSE: To improve the physical properties and reliability of a deep-drawn molded item by continuously or discontinuously depositing a thermoplastic polymer linearly on the warps and/or wefts of a two-directional fabric of reinforcing fibers and specifying the min. crossing angle of weaving yarns. CONSTITUTION: Mats 4a and 4b and carbon fiber fabrics 3a and 3b are cut along the warps and wefts into a certain size larger than the surface area of a die. The mat 4a as the first layer of a preform, the fabric 3a as the second layer, the mat 4b as the third layer, and the fabric 4b as the fourth layer are laid one on top of another in this order with the second and fourth layers shifted from the first and third layers by 45 deg.. The four corners of the fabrics and the four corners of the mats are fixed with a frame. The fixed fabrics and mats are placed on a female die and pressed with a male die, thus easily giving a deeply drawn preform 1 without causing creases on the fabrics. Pref. tension is applied a little outwardly at the fixing points. points 6 and 7 at the four corners, to facilitate the slippage to bring the min. crossing angle into the range of 20-40 deg..

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a preform for a fiber-reinforced composite material, which is expected to have excellent properties when molded, and a method for producing the same, and more particularly to a deep-drawn preform and a method for producing the same.

[0002]

2. Description of the Related Art Fiber reinforced composite materials, especially fiber reinforced plastics (hereinafter referred to as "FRP"), often use a reinforced woven fabric in the form of a woven fabric using carbon fiber threads, glass fiber threads, polyaramid fiber threads or the like. ing. Among them, a carbon fiber woven fabric having a large specific elastic modulus and a large specific strength is usually woven by a general shuttle loom or rapier loom, and formed into a predetermined shape by combining with a synthetic resin. Carbon fiber reinforced plastic (hereinafter,
It is often used as a reinforcing base material for composite materials such as "CFRP").

CFRP, in particular, has excellent mechanical properties, so that it is used in fishing rods, golf shafts, and aircraft.
It has been used as a skin material for the honeycomb sandwich structure of the next structural member. Since these have excellent mechanical properties and reliability of CFRP, carbon fibers are used in the form of continuous fibers, and are processed into unidirectional prepregs and woven fabrics and their prepregs, and then provided for molding. However, since these unidirectional prepregs and woven fabrics are sheet-like materials composed of continuous fibers, it is difficult to perform deep drawing, that is, it is difficult to form a deep drawn preform into a predetermined shape. However, there was a limitation in the shape to be naturally molded.

As a deep-drawn FRP molded product, for example, a helmet cap body is known. However, since it is difficult to fit a woven material into a mold without wrinkling, a woven fabric cut into small pieces of a predetermined size is used. A method of laminating and molding the female mold like a patchwork is adopted. However, in such a forming method, when the male material is pressed, the laminated positions of the woven material are displaced, a predetermined reinforcing effect cannot be obtained, and the cap body has a weak portion. Therefore, there is a problem that the helmet cap body becomes unnecessarily heavy in consideration of variations in the molding process from the viewpoint of safety. Further, since several dozen pieces of small-sized fiber base materials are laminated one by one, manpower is required, and there is a problem that productivity is poor.

Further, as a method for molding a deep-drawn molded product, a sheet molding compound (SMC) or chopped strand in which a strand of reinforcing fiber is cut into about 10 to 25 mm and randomly oriented to impregnate a resin -A method using a mat or a continuous strand mat in which continuous strands are oriented while drawing a loop is known, but since the reinforcing fibers are short fibers only with these fiber base materials, the orientation of the reinforcing fibers is also known. However, it was not possible to control the temperature, so the physical properties varied and the molded product did not become highly reliable. Further, since there is no continuous fiber arranged in a straight line, there is a problem that it is weak against impact.

[0006]

SUMMARY OF THE INVENTION The object of the present invention is to solve the problems of the conventional deep-drawing FRP molded product described above, to provide a deep-drawing FRP molded product having excellent physical properties and a small variation, and to form the same. It is to provide a preform to do.

Another object of the present invention is to provide a method for manufacturing such a preform with excellent workability at low cost.

[0008]

In order to achieve the above object, the deep-drawn preform of the present invention comprises a bidirectional woven fabric having reinforcing fibers as warp yarns and weft yarns, and at least the warp yarns and weft yarns are provided. On the other hand, the thermoplastic polymer is adhered linearly and continuously or discontinuously, and the minimum cross angle of the weaving yarns extending in two directions of the reinforcing fabric is 20 to 40 degrees. Become.

The thermoplastic polymer is, for example, a low melting point copolymerized nylon. This thermoplastic polymer
For example, it may be continuously extended in the form of a polymer yarn and continuously attached to at least one of the warp yarn and the weft yarn, or the polymer yarn may be heated and melted to form a discontinuous form, which is at least the warp yarn and the weft yarn. It is attached discontinuously on one side. The amount of the thermoplastic polymer attached to the woven yarn is preferably in the range of 0.2 to 5.0% by weight. Such a thermoplastic polymer can serve as a seal between the textile yarns when the preform is shaped into the desired shape. Therefore, even if deep drawing is performed, the flat state of the flat yarn described later can be formed without being crushed.

The minimum crossing angle is the crossing angle of both reinforcing fiber yarns in a portion of the above-mentioned reinforcing fabric in the deep-drawn state where the intersecting angle of the reinforcing fiber yarns extending in two directions is minimized. Say. That is, the deep drawing causes more or less misalignment in the woven yarn (reinforced fiber yarn extending in two directions) of the reinforcing fabric, and the misalignment changes the intersection angle of both woven yarns. Then, the angle of the portion where the crossing angle after this change becomes the minimum is called the minimum crossing angle. Usually, this minimum intersection angle occurs at or near the edge of the deep drawing region.

By setting the minimum crossing angle to be in the range of 20 to 40 degrees, a preform having no opening and a high cover factor can be obtained. The cover factor of this preform is preferably 85% or more, more preferably 90% or more.

In order to realize the above-described minimum crossing angle, each woven yarn of the reinforcing fabric to be deep-drawn is easy to move in the shearing direction at the time of deep-drawing, and at that time, a desirable form of the woven yarn is required. To maintain a high cover factor. For ordinary fabrics, it is difficult to perform deep drawing, or it is necessary to make cuts in order to prevent wrinkles that occur during deep drawing. When a woven fabric that is easy to move and can realize the above-described minimum cross angle is used, it is not necessary to make a break.

The reinforced woven fabric which can realize the above-mentioned minimum crossing angle in the deep-drawn state is, for example, a woven fabric which is a flat and substantially non-twisted reinforcing fiber multifilament yarn.

Here, "substantially no twist" means that there is no twist of 1 turn or more per 1 m of the yarn length. In other words, it means a realistic untwisted state.

When the woven yarn is twisted, the yarn width is narrowed and converged and thickened at the twisted portion, and unevenness occurs on the surface of the woven fabric. Therefore, when the woven fabric is woven, stress concentrates on the twisted portion when an external force acts, and
When molded into the same shape, the strength characteristics become non-uniform.

Such a flat reinforced woven fabric composed of a substantially non-twisted woven yarn is produced in the intersecting portion of the respective woven yarns even if the fineness of the woven yarn or the fiber density is increased. Crimp is kept extremely small, FRP and CFR
When P is used, high strength characteristics can be obtained. Since the fineness of the weaving yarn can be increased, the weaving yarn, and thus the reinforcing woven fabric, can be manufactured at a lower cost.

Further, since the crimp is suppressed to a very small value, the fabric weight can be set high and the cover factor can be set close to 100% while the flat state of the weaving yarn is secured. Therefore, in FRP or the like, the fiber content can be set high, and the resin-rich portion between the weaving yarns can be suppressed to an extremely small value, and a composite material having high strength and uniform strength characteristics can be obtained.

Further, since each woven yarn is maintained in a flat state in the form of a woven fabric, the resin impregnation property is extremely good. Therefore, a composite material having more uniform properties can be obtained, and target strength properties can be easily obtained.

In such a reinforced woven fabric according to the present invention, the reinforcing fiber multifilament yarn has a yarn thickness of 0.
It is preferable that the yarn width / thread thickness ratio is from 05 to 0.2 mm and 20 or more. If the yarn thickness is less than the above range, it becomes too thin to maintain the shape of the flat yarn, and if it exceeds the above range, it becomes difficult to suppress the crimp to a small extent.
When the yarn width / thickness ratio is less than 20, it is difficult to simultaneously maintain the form of the flat yarn and suppress crimp. Although the upper limit of the yarn width / thickness ratio is not particularly limited, the upper limit is about 150 in consideration of the ease of performing the actual weaving process. Also, as the thread width,
Weaving is easy in the range of 3 to 16 mm.

The reinforcing fabric used in the present invention as described above is
Can be woven in various forms. In the woven fabric of each form, the woven fabric thickness and fabric weight are preferably in the following ranges.

When the flat reinforcing fiber multifilament yarn is used as warp and weft, the fabric has a thickness of 0.07 to 0.4 mm and a fabric weight of 100 to 40.
It is preferably 0 g / m ² (woven fabric-1).

In the above woven fabric, when the reinforcing fiber multifilament yarn is a carbon fiber yarn, the number of filaments of the carbon fiber yarn is 5,000 to 24,000 and the fineness is 3,000 to 20,000 denier. Preferably there is.

In the case of a woven fabric in which flat reinforcing fiber multifilament yarns are used as warp yarns and weft yarns, and at least one of the warp yarns and the weft yarns is a woven fabric in which a plurality of reinforcing fiber multifilament yarns are laminated, Fabric thickness is 0.2-0.6mm, fabric weight is 200-60
It is preferably 0 g / m ² (woven fabric-2). Since it is a flat woven yarn, the crimp can be suppressed to a small level even if the yarn is woven in such a laminated state. The lamination can increase the fiber density of the fabric.

Here, the fiber density of the woven fabric means a value defined by the following equation. Textile fiber density (g / m ³ ) = [texture weight (g / m ³
m ² )] / [woven fabric thickness (mm)] Note that the fabric weight (g / m ² ) and the fabric thickness (mm)
Are values measured in accordance with JIS R7602.

In this woven fabric, when the reinforcing fiber multifilament yarn is a carbon fiber yarn, the number of filaments of the carbon fiber yarn is 3,000 to 12,000 and the fineness is 1,500 to 10,000 denier. Preferably there is.

As described above, the fineness is 3,000 to 20,0.
Even if a thick yarn of 00 denier or 1,500 to 10,000 denier is used, the flatness of the flat yarn is crushed or the texture becomes too coarse by setting the range of the optimum fabric weight above. It is possible to prevent the impregnating property of the above from being deteriorated.

When the reinforcing fiber yarn is a carbon fiber yarn, the characteristics of the carbon fiber flat yarn to be used are that the tensile elongation at break must be high and the tensile strength at break must be high. The tensile elongation at break is 1.5%. Above, tensile breaking strength is 200kgf / mm ²
As described above, it is desirable that the tensile elastic modulus is 20,000 kg · f / mm ² or more.

The reinforcing fabric used in the present invention in various forms as described above has, for example, a flat structure. Further, since a flat woven yarn is used and the crimp is extremely small, a large cover factor can be achieved.

For example, in the case of the above-mentioned woven fabric-1 and when the flat reinforcing fiber multifilament yarn is made of carbon fiber yarn, the fabric weight and the fineness of the carbon fiber yarn satisfy the following equation. , And the cover factor is 95
% Or more is preferable. W = k · D ^1/2 However, W: fabric weight (g / m ² ) k: proportional constant (1.4 to 3.6) D: fineness of carbon fiber yarn (denier)

Further, in the case of the above-mentioned form of woven fabric-2, and when the flat reinforcing fiber multifilament yarn is made of carbon fiber yarn, the relationship between the fabric weight and the fineness of the carbon fiber yarn is expressed by the following equation. Meet and cover factor is 9
It is preferably at least 5%. W = k · D ^1/2 However, W: fabric weight (g / m ² ) k: proportional constant (2.0 to 6.0) D: fineness of carbon fiber yarn (denier)

[0031] Here, the cover factor Cf, an element related to the size of the gap portion formed between weaving yarns, when setting a region of area S ₁ on the textile, in the area S ₁ yarn Let S ₂ be the area of the voids formed in 1. Then, the value is defined by the following equation. Cover factor Cf = [(S ₁ −S ₂ ) / S ₁ ] × 1
00

The reinforcing fabric as described above uses warp yarns or weft yarns made of thin flat reinforcing fiber multifilaments. Therefore, the woven fabric has a small degree of perforation, that is, a large cover factor. When a preform is deep-drawn using a reinforced woven fabric with such a large cover factor and then FRP is molded, a uniform molded product is obtained, and a fiber distribution in which voids are contained in the resin and stress is concentrated. No unevenness occurs.

As the method for producing the flat yarn itself as described above, for example, in the manufacturing process of the reinforcing fiber yarn,
A fiber bundle composed of a plurality of reinforcing fibers may be spread by a roll or the like to a predetermined width and kept in a flat shape, or may be held by a sizing agent or the like so as not to return to its original shape. In particular, in order to maintain the flat shape well,
It is preferable to attach a small amount of the sizing agent of about 0.5 to 1.5% by weight to the flat yarn.

The reinforcing woven fabric according to the present invention, which is woven using the warp yarn and / or the weft yarn made of the flat reinforcing fiber multifilament yarn, preferably has a woven structure substantially equal to each yarn width. As a result, a woven fabric having a high fiber density with almost no voids in the intersecting portion where the warp yarn and the weft yarn intersect.

However, since the warp yarns and the weft yarns actually intersect, it is difficult to make the yarn interval equal to the yarn width.
Therefore, in the woven woven woven fabric, the space between any one of the warp yarn and the weft yarn may be equal to the yarn width, and the other yarn interval may be slightly larger than the yarn width. However, if the yarn interval exceeds 1.2 times the yarn width, the voids become large and a woven fabric with a high fiber density cannot be obtained. Therefore, it is desirable that the warp or weft yarn woven yarn pitch is 1.0 to 1.2 times the yarn width, that is, the woven yarn pitch / thread width ratio is 1.0 to 1.2.

The preform of the present invention containing at least one bidirectional reinforcing woven fabric as described above is deep drawn from a raw woven fabric or a prepreg. In addition, if necessary, a mat made of reinforcing fibers may be laminated in layers, for example, a mat having a surface layer may be laminated. The lamination of the mat gives a smoother surface morphology when it is made into FRP.

One embodiment of the preform according to the present invention will be described with reference to the drawings. 1 and 2 show a preform used for forming a helmet cap body.
FIG. 2 is a schematic perspective view in which a part of the preform 1 according to the present invention is broken, and FIG. 2 is a vertical cross section of the preform 2 in which an end portion of the fiber base material of the preform 1 in FIG. 1 is removed along a dashed line in the figure. It is a figure. FIG. 3 is a plan view of the preform 1 of FIG. In the present invention, in addition to the preform 1, the preform 2 from which the excess portion after deep drawing is removed is also
It is called a preform.

The preforms 1 and 2 are carbon fiber woven fabrics 3a in which a thermoplastic polymer is linearly and continuously or discontinuously attached to at least one of warp yarns and weft yarns.
3b and continuous strand mats 4a and 4b made of glass fiber, which are four layers of reinforcing fiber base material, and the convex portions 1a and 2a of the preforms 1 and 2 (deep drawing portion).
From the outer layer to the first layer is a continuous strand mat 4a, the second layer is a carbon fiber fabric 3a, the third layer is a continuous strand mat 4b, and the fourth layer is The carbon fiber woven fabrics 3b are laminated so that the carbon fiber woven fabrics and the reinforcing fiber base material of the continuous strand mat do not have wrinkles, and the hemispherical shell-shaped preforms 1 and 2 are integrally formed without breaks. Covers. The carbon fiber woven fabric 3a of the second layer has X1-X1 axes and Y1-Y.
The warp yarns and the weft yarns are obliquely oriented with respect to one axis, and the carbon fiber woven fabric 3b of the fourth layer has X1-X1 axis, Y-axis.
1-Y2-axis, X2-X2 axis, which is 45 degrees out of phase, Y2-
The warp yarns and the weft yarns are obliquely oriented with respect to the Y2 axis. The two carbon fiber fabrics 3a and 3b of the second layer and the fourth layer make the mechanical properties pseudo isotropic.

The carbon fiber woven fabrics 3a and 3b are woven fabrics having a flat structure, and the warp yarns and the weft yarns are woven at an intersection angle of 90 degrees before the preforms 1 and 2 are formed.
In the deep-drawn preforms 1 and 2, the respective weaving yarns are misaligned by deep drawing, and the minimum crossing angle θ is within the range specified in the present invention. This minimum intersection angle θ is
In the present embodiment, the deep drawing region (preform convex portion 1a,
It occurs on the edge of 2a).

In the above description, the preform using the two-layer carbon fiber woven fabric has been described, but at least one layer of the carbon fiber woven fabric may be used, and the rest may be other reinforcing fiber base materials. Also, a preform using two types of reinforcing fiber base materials, that is, a continuous strand mat made of glass fiber and a carbon fiber woven fabric has been described, but it goes without saying that a mat is not used and all are carbon fiber woven fabrics. The fiber orientation due to lamination is preferably, but not limited to, the carbon orientation of the carbon fiber woven fabric, as described above. Similarly, the number of laminated layers is not limited to the above four layers, and can be appropriately determined according to the characteristics and thickness required of the molded product.

If the first layer from the outer layer of the convex portion is a mat layer made of glass fiber or vinylon fiber, the black color of the carbon fiber cannot be easily seen when the molded product is coated. As a result, molded products having various colors can be obtained, and the smoothness of the FRP surface is improved, so that molded products of high commercial value can be obtained.

By closely observing the situation where the carbon fiber woven fabric fits the mold, the carbon fiber has a large tensile elastic modulus and therefore hardly expands. When deformed, the warp (0 degree) and weft (90 degree) fiber-orientation parts with respect to the mold are stretched, and the diagonal fiber orientation (± 45 degrees) fiber-orientation part is the crossing angle of the weaving thread. The fabric was fitted to the mold by misalignment deformation so that In the preform, there is a portion where the crossing angle of the woven thread is originally 90 degrees, but the crossing angle changes variously due to misalignment, and the preform having a higher degree of drawing has a smaller crossing angle of the woven thread. . In addition, as a result of diligent studies, a carbon fiber woven fabric is formed 2
If the minimum crossing angle of the carbon fiber in the preform in the preform is 20 to 40 degrees as specified in the present invention, a normal deep-drawing CFRP molded product, for example, a preform for a helmet cap body, a housing, or a speaker cone is formed. It was found that it is possible to fabricate the fabric without making a cut.

That is, if the minimum intersecting angle in the preform is 40 degrees or more, the preforms for these deep-drawn molded articles will be wrinkled preforms in the woven fabric and will not be wrinkled. It is necessary to make a cut in the woven fabric to prevent the entry. Further, when the minimum crossing angle is 20 degrees or less, the degree of crossing of the warp yarn and the weft yarn in this portion becomes tight, and when the FRP is molded, the resin impregnation property becomes poor, and the bending of the woven yarn, that is, the crimp becomes large. However, there is a problem that strength is reduced due to stress concentration.

In order to integrally cover the entire surface of the hemispherical shell-shaped preform without wrinkles or cuts, a mesh-like carbon having a large gap between the yarns and a large void formed by the woven yarn is formed. This is possible if fiber fabrics are used. In this case, in the portion where the fibers are oriented in the oblique direction, misalignment deformation occurs, the crossing angle of the woven yarn becomes small, and the yarn interval becomes small
The voids formed by the weaving yarn of the carbon fiber woven fabric in this portion are small, that is, the cover factor is large, but the warp yarn (0 °) and the weft yarn (90) with respect to the mold
Since the portion in which the fiber orientation is at (°) does not undergo misalignment deformation even along the mold, the voids formed by the woven yarn are as large as the original mesh-like carbon fiber woven fabric. That is, the cover factor is small.

However, in the present invention, by using the reinforcing woven fabric having the above-mentioned flat and substantially non-twisted reinforcing fiber multifilament yarn as a woven yarn, a high cover factor can be obtained without using a mesh woven fabric. Will be realized.

The cover factor of the carbon fiber woven fabric in the preform is preferably 85% or more as described above. When a preform with a small cover factor of carbon fiber woven fabric is molded, the surface of the FRP molded product becomes uneven, and the resin is unevenly distributed in the voids formed by the weaving yarn, resulting in resin excess, and cracks occur in this part. Also, voids are concentrated and the strength of FRP is reduced. In addition, since there is no carbon fiber in this part in a partial view, a locally extremely weak part exists.

In the carbon fiber woven fabric used for the above-mentioned preforms 1 and 2, the warp yarn and the weft yarn made of flat carbon fiber multifilament yarn are woven with a very coarse density, and further, the crimp of the woven yarn is small. , It is easy to misalign the weaving thread. That is, when the carbon fiber woven fabric is deformed by misalignment, there is sufficient margin to close the yarn interval of the warp yarn or the weft yarn, so that the yarn interval of the flat yarn is reduced while the yarn interval is reduced, and a large amount is obtained without causing wrinkles. It can be transformed. That is, it is possible to reduce the angle of intersection between the warp yarn and the weft yarn, without wrinkling in the carbon fiber woven fabric, and it is possible to cover the entire surface of the hemispherical shell-like preform integrally with no break, and the physical properties are high, A deep-drawn FRP molded product with less variation can be obtained.

Further, since the thermoplastic polymer is adhered to the carbon fiber woven fabrics of the preforms 1 and 2 for sealing, the thermoplastic polymer is appropriately heated, for example, at the time of shaping the preform. The adhesive force of the polymer does not cause local bending of the flat yarns or displacement of the intersection points of the respective weaving yarns, and it is possible to change only the intersection angle of the respective weaving yarns, resulting in misalignment of the weaving yarns and flatness of the flat yarns. It is possible to perform deep drawing without causing a collapse. Therefore, since the reinforcing fibers are uniformly covered in the preform, when the preform is impregnated with resin and molded, a surface smooth FRP can be obtained.

The carbon fiber of the carbon fiber woven fabric used in the preform of the present invention has a single fiber diameter of 5 to 20 microns and a tensile modulus of elasticity of 18 × 10 ³ kgf / mm ² measured according to JIS R7601. Above, tensile strength is 25
Products with a shock resistance of 0 kgf / mm ² or more, such as helmet caps, have a tensile modulus of 2
0 × 10 ³ kgf / mm ² or more, and the fracture strain energy w defined by the following formula is 4.0 mm · kgf / mm ³
The above high toughness carbon fiber is preferable. w = σ ² / 2E σ: tensile strength of carbon fiber (kgf / mm ² ) E: tensile modulus of carbon fiber (kgf / mm ² ).

The preform according to the present invention as described above is formed by deep drawing as follows. That is, in the method for producing a preform of the present invention, a reinforcing base material including at least one bidirectional reinforcing fabric is provided in a direction oblique to the direction in which the weaving yarn orientation direction of the reinforcing fabric is directed to the deep drawing center. The method is characterized in that deep corner shaping is performed by fixing at each corner.

As described above, the reinforcing woven fabric is preferably a woven fabric which is a flat and substantially non-twisted reinforcing fiber multifilament yarn. Further, as the reinforcing base material to be deep-drawn, raw reinforcing fabric may be used,
At least one layer of the reinforcing base material may be in the form of a prepreg.

A method for producing a preform according to the present invention,
To describe the preforms shown in FIGS. 1 to 3 above, first, the mats 4a, 4b and the carbon fiber fabrics 3a, 3b are formed into rectangular shapes along the warp and weft threads to a predetermined size larger than the surface area of the mold. Cut into squares. Next, the mat 4a, which is the first layer of the preform,
The second layer of carbon fiber woven fabric 3a, the third layer of mat 4b, and the fourth layer of carbon fiber woven fabric 3b
The carbon fiber woven fabrics 3a and 3b of the fourth layer and the fourth layer are shifted by 45 degrees and overlapped. Next, fix the four corners of each of the second and fourth layers of carbon fiber woven fabric with a frame, preferably also fix each of the four corners of the mat together with the woven fabric and place them on the female mold. By pressing, deep drawing can be easily performed without wrinkling the woven fabric. As a result, the preform 1 is molded. Simultaneously with shaping, the preform 2 can be manufactured easily and efficiently by cutting off the fibrous base material that is pushed out in the corners by pressing.

The fixed points in the deep drawing are the four corner points 6 and 7 in which the weaving direction of the carbon fiber woven fabrics 3a, 3b is oblique to the direction of the deep drawing center 5. . This fixing may be fixed at a fixed point completely, but it is more preferable to apply tension slightly outward, because it is easy to cause misalignment for keeping the minimum intersection angle θ within a predetermined range.

When the continuous strand mat is used as the reinforcing fiber base material other than the carbon fiber as described above, the loop-shaped strands stretch and fit the mold even when deep drawing is performed, It is preferable because the substrate is not cut by shaping.

In the above-mentioned preform manufacturing method, the case where all the fiber base materials are shaped at the same time has been described. However, it is also possible to shape one fiber base material at a time and stack each fiber base material to form a preform. Good.

In the production of the preform, a continuous strand mat whose form is fixed by a binder of a thermoplastic polymer is used as a mat, or as described above, a binder of a thermoplastic polymer is attached as a reinforcing fabric. Use a carbon fiber woven fabric, or interpose a powdery, thread-like or ultrathin non-woven fabric as a binder of the thermoplastic polymer between the carbon fiber woven fabric and the mat, and move the mold above the softening point of these thermoplastic polymers. When heated and shaped, the shape of the preform taken out from the mold is stabilized, and the subsequent molding becomes easy. As such a thermoplastic polymer, those having a low melting point and not impairing the properties of FRP are preferable, and in addition to the low melting point copolymer nylon as described above, a resin or a low melting point polyester resin can be used. In order not to deteriorate the characteristics of FRP, it is preferable that the adhesion amount is as small as possible, and it is about 0.2 to 5.0% by weight based on the fiber weight of the preform.

As described above, a prepreg obtained by impregnating a carbon fiber woven fabric with a B-stage thermosetting matrix resin in advance can also be used as a fiber base material for producing the preform or FRP of the present invention. . The thermosetting matrix resin is an epoxy resin, an unsaturated polyester resin, a vinyl ester resin or a phenol resin, and the resin ratio in the prepreg is about 30 to 60% by weight.

Further, the FRP according to the present invention is molded using the preform manufactured as described above. In this FRP, a thermosetting resin or a thermoplastic resin can be used as the matrix resin. The matrix resin preferably has a tensile elongation at break higher than the tensile elongation at break of the woven yarn of the reinforcing fabric.
A thermosetting resin having a tensile elongation at break of 3.5 to 10% or a thermoplastic resin having a tensile elongation at break of 8 to 200% is preferable.

Examples of the matrix resin used include thermosetting resins such as epoxy resin, unsaturated polyester resin, polyimide resin and phenol resin. These thermosetting resins are B stage when impregnated into the fabric. As the matrix resin, nylon resin,
Polyester resin, polybutylene terephthalate resin,
Thermoplastic resins such as polyetheretherketone (PEEK) resin and bismaleimide resin can also be used.

The FRP according to the present invention can be molded by a usual molding method. For example, the above-mentioned preform is manufactured in a heated female mold, and a liquid thermosetting resin containing a curing agent, which is weighed, is put into this female mold, and then added with a heated male mold. It can be easily molded by pressing.

The FRP molded product may take various forms. For example, a helmet cap, a housing, a speaker cone, and the like.

In a deep-drawing FRP molded article such as a helmet cap, housing, and speaker cone according to the present invention, a fiber-reinforced resin molding preform containing at least one layer of reinforcing woven fabric is used. The minimum intersection angle is 20 to 40 degrees. In the form of a preform, the woven fabric can be made integral without breaks, and the cover factor in each part can be 85% or more.

Such an FRP molded product is a deep-drawing molded product, but the warp and weft of the reinforced fabric are not cut, there are no wrinkles, and the cover factor is large, so the physical properties and performance of the molded product are high. Good and there is little variation. In addition, since the thermoplastic polymer can seal the weaving yarns of the woven fabric, unfavorable misalignment does not occur even when deep drawing is performed, and the flat state of the flat yarn is not crushed. Therefore, a lightweight and highly reliable product can be obtained.

Further, in the deep-drawing FRP molded product, at least one layer of the reinforcing woven fabric continuously and continuously contains the reinforcing fibers, so that even a chopped strand mat of a short fiber type, Although it is a continuous fiber, it is a molded product with good impact resistance when used in combination with a continuous strand mat in which the strands are arranged while drawing a loop.

[0065]

The preferred embodiments of the present invention will be described below. Example 1 Flat carbon fiber having a yarn width of 6.5 mm and a yarn thickness of 0.12 mm ("Torayca" T700SC-12K manufactured by Toray Industries, Inc.)
(Fineness 7,200 denier)), with a plain weave structure, a weaving density of warp threads and weft threads of 1.25 yarns / cm, and weaving while maintaining a flat shape. At the time of weaving, warp yarns are used. Weaving copolymer nylon yarn with
A woven fabric having a basis weight of 200 g / m ² was obtained by heating to a temperature not lower than the melting point of the copolymerized nylon yarn with a heater provided up to the winding roller. The cover factor of the resulting fabric is 9
The woven fabric had almost no voids between 9% and the yarn.

Next, four woven fabrics cut into 60 cm squares with one side in the weaving yarn direction were prepared, and the center of each cut woven fabric was aligned, and the weaving yarn angle was (0 °, 90 °) / (± 45
°) / (± 45 °) / (0 °, 90 °).

Then, the laminated woven fabric base material is heated in advance above the softening point temperature of the sealing yarn (copolymerized nylon polymer), placed on a female mold taken from the helmet, and the weaving yarn orientation of each woven fabric. Each corner, which is a direction oblique to the direction of the deep drawing center, was fixed, and a male mold was pressed onto the corners for shaping.

The preform obtained by the above-mentioned method was shaped as a helmet mold without wrinkles. The cover factor of the preform was 98%, which was very smooth with few voids. Further, the bias direction of each woven fabric in the preform was in a stretched form, and the minimum intersecting angle of the woven yarn was greatly sheared and deformed to 35 degrees.

The above preform was impregnated with a thermosetting vinyl ester resin using a molding die to obtain a molded product. The obtained molded product was a product in which the high cover factor in the preform was maintained, the resin was not unevenly distributed, the carbon fibers were uniformly dispersed, and the surface was smooth. In addition, when the cross-section of the molded product was observed, there was no void and the resin was uniformly impregnated.

Comparative Example 1 As a comparative example, an ordinary carbon fiber woven fabric (# 6343: "Torayca" T300-3K manufactured by Toray Industries, Inc. (fineness 1,80
Using 0 denier), the shapeability of a plain weave fabric of 200 g / m ^{2 with} basis weight) was evaluated in the same manner as in Example 1 above. In the obtained preform, wrinkles were generated in the bias direction portion of each cut fabric at the edge portion of the helmet. Further, the weft yarn crossing angle in the bias direction was 50 degrees, which was smaller than that of the preform of Example 1.

That is, in the ordinary carbon fiber woven fabric used in this comparative example, the respective weaving yarns approached with respect to the elongation in the bias direction and were restrained.

Although the preform was molded by the same method as in the example, it was thick because it could not be molded to the set thickness due to the presence of wrinkles. As a result, there were many places where the resin was lacking due to lack of resin, and the surface was uneven. In addition, since no stopper thread was used, non-uniform misalignment occurred at various points of the fabric during deep drawing.

Comparative Example 2 For the purpose of increasing the elongation in the bias direction, the same carbon fiber yarn as in Comparative Example 1 was used, and a woven fabric having a coarse weaving yarn density of 3 yarns / cm was prepared and compared. Fabric weight is 120g / m ²
The cover factor was 80%, which was a coarse mesh.

The obtained woven fabric was evaluated for shapeability in the same manner as in Example 1. No wrinkle was found in the shaped preform, but the binding of the woven yarn is very weak, so
The woven yarn was greatly misaligned during shaping. Also,
At the top of the helmet that was not sheared, there was no misalignment, but the cover factor was still the cover factor of the original fabric, so it was open.

The above preform was molded in the same manner as in Example 1. The resulting molded product was uneven in that the misalignment and low cover factor seen in the preform were shown as they were, and the resin was unevenly distributed in the misalignment and the gaps between the weaving yarns. Further, the unevenly distributed portion of the resin was recessed due to the curing shrinkage of the resin, and the product had poor surface smoothness. As described above, a woven fabric having a coarse mesh is apt to be sheared and deformed, but there is a problem in that it causes misalignment and there are vacant spaces, and therefore it cannot be used for a fiber-reinforced plastic that requires reliability.

[0076]

As described above, the preform of the present invention and the deep-drawn molded product of the preform of the present invention can be used for the purpose of specifying the minimum crossing angle of the reinforcing fabric woven yarn in the preform and for sealing. Since a thermoplastic polymer is attached, it is possible to maintain the desired fabric form and flat yarn form during deep drawing, and even when deep drawn, the reinforcing fabric does not break or wrinkle. In addition, since it has a large cover factor, it can be a lightweight and highly reliable FRP product.

Further, since at least one layer of the reinforcing woven fabric has no breaks and the carbon fibers are continuously contained in the entire molded article, although it is a chopped strand mat of short fibers or continuous fibers, Even when used in combination with a continuous strand mat, in which the strands are arranged while drawing a loop, it is a molded product with good impact resistance.

Furthermore, according to the method for producing a preform of the present invention, the desired deep-formed preform is shaped by simply fixing the corners of the fabric, and the deep-drawn molding is performed. Since the product is molded, the productivity is good.

[Brief description of drawings]

FIG. 1 is a perspective view of a preform according to an embodiment of the present invention.

FIG. 2 is a vertical cross-sectional view of the preform in which the peripheral portion of the preform of FIG. 1 is cut and removed.

FIG. 3 is a schematic plan view of the preform of FIG.

[Explanation of symbols]

 1, 2 Preform 1a, 2a Convex part (deep drawing part) 3a, 3b Reinforcing woven fabric (carbon fiber woven fabric) 4a, 4b Mat 5 Deep drawing center 6,7 Fixed part θ Minimum cross angle

Claims (27)

[Claims] 1. A warp yarn and a weft yarn as reinforcing fibers 2
A directional woven fabric, a thermoplastic polymer is linearly and continuously or discontinuously attached to at least one of the warp yarn and the weft yarn, and the minimum cross angle of the woven yarns extending in two directions of the reinforcing fabric is 20. A deep-drawn preform, characterized in that it is -40 degrees. 2. The preform of claim 1, wherein the thermoplastic polymer is a low melting point copolymerized nylon. 3. The preform according to claim 1, wherein the amount of the thermoplastic polymer attached to the yarn is 0.2 to 5.0% by weight. 4. The reinforcing fabric is seamless.
The preform according to any one of 1 to 3. 5. The cover factor of the reinforcing fabric is 85.
The preform according to any one of claims 1 to 4, which is at least%. 6. The preform according to claim 1, wherein the reinforcing woven fabric is a woven fabric having a reinforcing fiber multifilament yarn that is flat and has substantially no twist. 7. The preform according to claim 6, wherein the reinforcing fiber multifilament yarn has a yarn thickness of 0.05 to 0.2 mm and a yarn width / yarn thickness ratio of 20 or more. 8. The woven fabric wherein the reinforcing fiber multifilament yarn is a warp yarn and a weft yarn,
Fabric thickness is 0.07-0.4mm, fabric weight is 100-
Preform according to claim 6 or 7, which is 400 g / m ² . 9. The reinforcing fiber multifilament yarn is a carbon fiber yarn, and the number of filaments of the carbon fiber yarn is 5,
000 to 24,000, fineness of 3,000 to 20,0
9. The preform according to claim 6, which has a denier of 00. 10. The reinforcing fabric is a fabric in which the reinforcing fiber multifilament yarn is a warp yarn and a weft yarn, and at least one of the warp yarn and the weft yarn is formed by laminating a plurality of the reinforcing fiber multifilament yarns, and the fabric thickness is 0.2-0.6 mm, fabric weight 200-600 g /
The preform of claim 6 or 7, which is m ² . 11. The reinforcing fiber multifilament yarn is a carbon fiber yarn, and the number of filaments of the carbon fiber yarn is 3,000 to 12,000 and the fineness is 1,500 to 1.
The preform of claim 6, 7 or 10 which is denier of 10,000. 12. The preform according to claim 1, wherein the reinforcing fabric has a flat structure. 13. The preform according to claim 1, wherein a mat made of reinforcing fibers is laminated on the reinforcing fabric. 14. The reinforcing fiber multifilament yarn is made of carbon fiber yarn, the fabric weight and the fineness of the carbon fiber yarn satisfy the relationship of the following expression, and the cover factor is 95% or more. Reinforcing fabric for preform of 8. W = k · D ^1/2 However, W: fabric weight (g / m ² ) k: proportional constant (1.4 to 3.6) D: fineness of carbon fiber yarn (denier) 15. The reinforcing fiber multifilament yarn comprises a carbon fiber yarn, the fabric weight and the fineness of the carbon fiber yarn satisfy the relationship of the following equation, and the cover factor is 95% or more. Reinforcing fabric for 10 preforms. W = k · D ^1/2 However, W: fabric weight (g / m ² ) k: proportional constant (2.0 to 6.0) D: fineness of carbon fiber yarn (denier) 16. A bidirectional woven fabric comprising reinforcing fibers as warp yarns and weft yarns, comprising a reinforced fabric having a thermoplastic polymer linearly and continuously or discontinuously attached to at least one of the warp yarns and the weft yarns. Manufacturing of a preform, characterized in that the reinforcing base material is deep-drawn by fixing it at each corner where the direction of the woven yarn of the reinforcing fabric is a direction oblique to the direction of the deep-drawing center. Method. 17. The method for producing a preform according to claim 16, wherein the reinforcing woven fabric is a woven fabric having a reinforcing fiber multifilament yarn which is flat and has substantially no twist. 18. The method for producing a preform according to claim 16, wherein the reinforcing base material is in the form of a prepreg. 19. The method for producing a preform according to claim 16 or 17, wherein the thermoplastic polymer is heated to a softening point or higher and deep-drawn. 20. The method for producing a preform according to claim 18, wherein the prepreg is heated to be deep-drawn. 21. A fiber-reinforced plastic molded by using the preform according to claim 1. 22. The fiber reinforced plastic according to claim 21, wherein the matrix resin is a thermosetting resin or a thermoplastic resin. 23. The fiber reinforced plastic according to claim 21, wherein the tensile breaking elongation of the matrix resin is larger than the tensile breaking elongation of the woven yarn of the reinforcing woven fabric. 24. The matrix resin is a thermosetting resin having a tensile elongation at break of 3.5 to 10% or a tensile elongation at break of 8.
~ 200% thermoplastic resin.
The fiber-reinforced plastic according to any one of 3 above. 25. The fiber-reinforced plastic according to any one of claims 21 to 24, which is molded into a helmet cap body. 26. The fiber reinforced plastic according to claim 21, which is molded into a housing. 27. The fiber-reinforced plastic according to claim 21, which is molded into a speaker cone.