JP3214646B2 - Preform and manufacturing method thereof - Google Patents

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 can be 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 A fiber-reinforced composite material, particularly a fiber-reinforced plastic (hereinafter referred to as "FRP"), often uses a reinforced fabric formed of a woven fabric using carbon fiber yarn, glass fiber yarn, polyaramid fiber yarn, or the like. ing. Above all, carbon fiber woven fabrics made of carbon fibers having a large specific elastic modulus and a large specific strength are usually woven by a general shuttle loom or rapier loom, and formed into a predetermined shape by compounding with a synthetic resin. Carbon fiber reinforced plastics (hereinafter,
It is widely used as a reinforcing base material used for composite materials such as “CFRP”.

[0003] In particular, CFRP is excellent in its mechanical properties, and is therefore used in fishing rods, golf shafts and other aircraft.
It has been used as a skin material of a honeycomb sandwich structure as the next structural member. Since these are excellent in mechanical properties and reliability of CFRP, carbon fibers are used in the form of continuous fibers, and are processed into unidirectional prepregs or woven fabrics and prepregs thereof and provided for molding. However, since these unidirectional prepregs and woven fabrics are sheet-like materials composed of continuous fibers, deep drawing is difficult, that is, it is difficult to form a preform that is deep drawn into a predetermined shape. However, the shape to be naturally formed was limited.

As a deep drawn FRP molded product, for example, a helmet cap is known, but since it is difficult to fit a woven material without wrinkling a molding die, a woven fabric cut into small pieces of a predetermined size is used. A method of laminating and molding a female mold in a patchwork manner has been adopted. However, in such a molding method, when pressing with a male mold, the laminating position of the woven material is shifted, a predetermined reinforcing effect cannot be obtained, and the cap body has a weak portion. Therefore, there is a problem that the helmet cap becomes heavier than necessary in consideration of the variation in the molding process from the viewpoint of safety. Further, since several tens of small pieces of fiber base material are laminated one by one, labor is required and there is a problem that productivity is poor.

[0005] As a method of forming a deep drawn product, a strand of reinforcing fiber is cut to about 10 to 25 mm, randomly oriented, and impregnated with a resin, such as a sheet molding compound (SMC) or a chopped strand.・ Continuous strand mats, in which mats and continuous strands are oriented while drawing loops, are known.However, with these fiber substrates alone, the reinforcing fibers are short fibers, and the orientation of the reinforcing fibers is also high. However, physical properties fluctuated due to the lack of control, and a highly reliable molded product was not obtained. Further, since continuous fibers arranged in a straight line are not included, there is a problem that the fibers are weak against impact.

[0006]

SUMMARY OF THE INVENTION An object of the present invention is to solve the above-mentioned problems of the above-described deep drawn FRP molded product, and to provide a deep drawn FRP molded product having excellent physical properties and small variations. It is to provide a preform to perform.

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

[0008]

In order to achieve the above object, a deep-drawn preform according to the present invention is provided with a cover.
Factor includes two directional reinforcement fabric is 85% or more, the minimum intersection angle of yarn extending in two directions of the reinforcing fabric 2
0-45 degrees der is, the reinforcing fabric twisted flat substantially
Woven fabric using reinforced multifilament yarn without fiber
The reinforcing fiber multifilament yarn is made of carbon fiber
And the number of filaments of the carbon fiber yarn is 5,000.
~ 24,000, fineness of 3,000 ~ 20,000
It is characterized by being Neil .

Here, the minimum intersection angle is the intersection angle between the reinforcing fiber yarns in a portion where the crossing angle of the reinforcing fiber yarns extending in two directions in the reinforcing fabric in the state of deep drawing 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 between the two woven yarns. The angle of the portion where the intersection angle after the change becomes minimum is referred to as the minimum intersection angle. Usually, this minimum intersection angle occurs at or near the edge of the deep drawing area.

By setting the minimum intersection angle in the range of 20 to 45 degrees, a preform having no openings and a high cover factor can be obtained. The cover factor of this preform is 85% or more , preferably 90% or more.

In order to realize the minimum intersection angle as described above, each yarn of the reinforcing fabric to be deep-drawn is easily moved in the shearing direction during the deep-drawing, and the desired shape of the yarn is also required. To maintain a high cover factor. In ordinary woven fabrics, deep drawing is difficult or it has to be cut in order to prevent wrinkles that occur during deep drawing, but as described above, the woven yarn moves in the shear direction. If a reinforcing fabric which is easy to move and can realize the minimum intersection angle as described above is used, it is not necessary to make a cut.

The reinforcing woven fabric capable of realizing the above minimum intersection angle in the deep drawn state is, for example, a woven fabric made of a flat and substantially twistless reinforcing fiber multifilament yarn.

Here, "substantially no twist" refers to a state in which there is no more than one turn of twist per 1 m of yarn length. That is, it is a state in which there is no twist.

If the woven yarn is twisted, the yarn width becomes narrow and converges at the twisted portion to increase the thickness, and irregularities occur on the surface of the woven fabric. For this reason, in the woven fabric, when an external force acts, stress concentrates on the twisted portion, and the FRP
When formed into a uniform shape, the strength characteristics become non-uniform.

[0015] Such a reinforcing woven fabric made of a woven yarn in a flat state and having substantially no twist, even if the fineness of the woven yarn is increased or the fiber density is increased, is obtained at the intersection of the woven yarns. Crimp is kept very small, FRP and CFR
When P is set, high strength characteristics are obtained. Since the fineness of the woven yarn can be increased, the woven yarn, and thus the reinforced woven fabric, can be manufactured at lower cost.

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

Furthermore, since each yarn is maintained in a flat state in the form of a woven fabric, the impregnating property of the resin is extremely good. Therefore, a composite material having more uniform characteristics can be obtained, and a desired strength characteristic can be easily obtained.

In the reinforcing fabric according to the present invention, the reinforcing fiber multifilament yarn has a yarn thickness of 0.1 mm.
It is preferable that the yarn width / thickness ratio is 30 or more. If the yarn thickness is less than the above range, it is 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 value.
When the yarn width / yarn thickness ratio is less than 30, it is difficult to simultaneously maintain both the shape of the flat yarn and suppress the crimp. Although the upper limit of the yarn width / yarn thickness ratio is not particularly limited, the upper limit is about 150 in consideration of the easiness of the actual weaving process. Also, as the yarn width,
The range of about 4 to 16 mm is easy to weave.

The reinforcing fabric used in the present invention as described above includes:
It can be woven into various forms. In each type of woven fabric, the woven fabric thickness and woven fabric weight are preferably in the following ranges.

When the flat reinforcing fiber multifilament yarn is used as a warp and a weft, the woven fabric has a woven fabric thickness of 0.07 to 0.4 mm and a woven fabric weight of 100 to 30.
It is preferably 0 g / m ² (fabric-1).

In the above woven fabric, 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.
The range is from 0 to 20,000 denier .

Further, in the case of a woven fabric in which a flat reinforcing fiber multifilament yarn is a warp yarn and a weft yarn, at least one of the warp yarn and the weft yarn is a woven fabric in which a plurality of the reinforcing fiber multifilament yarns are laminated, The fabric thickness is 0.2 to 0.6 mm, and the fabric weight is 200 to 50.
It is preferably 0 g / m ² (fabric-2). Since it is a flat woven yarn, crimping can be suppressed to a small value even when woven in such a state that a plurality of layers are laminated. Lamination can increase the fiber density of the woven fabric.

Here, the fiber density of the woven fabric means a value defined by the following equation. Fiber density of fabric (g / m ³ ) = [weight of fabric (g / m ³ )
m ² )] / [fabric thickness (mm)] The fabric weight (g / m ² ) and the fabric thickness (mm)
Is a value measured according to JIS R7602.

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

As described above, the fineness is 3,000 to 20,000.
Even if a thick yarn having a denier of 00 denier or 1,500 to 10,000 denier is used, the flat yarn may be flattened, the weave may be too coarse, or resin may be formed by adjusting the above-mentioned optimum fabric weight. The impregnating property can be prevented from deteriorating.

When the reinforcing fiber yarn is a carbon fiber yarn, the properties of the carbon fiber flat yarn used are required to have a large tensile elongation at break and a high tensile elongation at break, and a tensile elongation at break of 1.5%. As described above, the tensile breaking strength is 200 kg · f / mm ²
As described above, the tensile modulus is desirably 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, it is possible to achieve a large cover factor.

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 basis weight of the woven fabric and the fineness of the carbon fiber yarn satisfy the following relationship. And the cover factor is 95
% Is preferable. W = k · D ^1/2 where W: fabric weight (g / m ² ) k: proportionality constant (1.4 to 3.6) D: fineness of carbon fiber yarn (denier)

Further, in the case of the above-mentioned 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 where W: fabric weight (g / m ² ) k: proportionality constant (2.0 to 6.0) D: fineness of carbon fiber yarn (denier)

[0030] 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 Assuming that the area of the void formed in the above is S ₂ , it means a value defined by the following equation. Cover factor Cf = [(S ₁ −S ₂ ) / S ₁ ] × 1
00

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

As a method of 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 to a predetermined width by a roll or the like, and may be held in a flat shape or may be held in a sizing agent or the like so as not to return to the original shape. In particular, to maintain the flat shape well,
It is preferable to attach a small amount of 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 composed of the flat reinforcing fiber multifilament yarn, preferably has a woven structure substantially equal to each yarn width. Thereby, in a crossing portion where the warp yarn and the weft yarn intersect, a woven fabric having almost no void and having a high fiber density is obtained.

However, since the warp and the weft are actually crossed, it is difficult to make the yarn interval equal to the yarn width.
Therefore, in the woven reinforcing fabric, the interval between any one of the warp yarn and the weft yarn may be equal to the yarn width, and the interval between the other yarns 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 having a high fiber density cannot be obtained. For this reason, it is desirable that the woven yarn pitch of the warp yarn and the weft yarn is 1.0 to 1.2 times the yarn width, that is, the woven yarn pitch / yarn width ratio is 1.0 to 1.2.

The preform of the present invention containing at least one bidirectional reinforcing fabric as described above is formed by deep drawing of a raw fabric or by deep drawing from a prepreg. Further, if necessary, a mat made of reinforcing fibers may be laminated in a layered manner, for example, a mat in which the mat is laminated as a surface layer. 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 molding a helmet cap, and FIG.
FIG. 2 is a schematic perspective view of a preform 1 according to the present invention, in which a part of the preform 1 is broken, and FIG. 2 is a longitudinal section of a preform 2 in which an end portion of a fiber base material of the preform 1 in FIG. FIG. FIG. 3 is a plan view of the preform 1 of FIG. In the present invention, together with the preform 1, the preform 2 from which an extra portion after deep drawing is removed is also provided.
It is called a preform.

The preforms 1 and 2 are made of carbon fiber fabric 3
a, 3b and four layers of continuous strand mats 4a and 4b made of glass fiber, made of a reinforcing fiber base material, and the projections 1a and 2a of the preforms 1 and 2 (deep drawn parts)
From the outer layer portion, the first layer has a continuous strand mat 4a, the second layer has a carbon fiber fabric 3a, the third layer has a continuous strand mat 4b, and the fourth layer has a continuous strand mat 4b. The carbon fiber fabrics 3b are laminated, and the carbon fiber fabrics and the reinforcing fiber base material of the continuous strand mat do not have wrinkles, and have no cuts and are integrally formed with the entire hemispherical shell-shaped preforms 1, 2. Is covered. The second-layer carbon fiber fabric 3a has an X1-X1 axis, Y1-Y
The warp and the weft are oriented in a diagonal direction with respect to one axis, and the carbon fiber fabric 3b of the fourth layer has an X1-X1 axis and a Y axis.
X2-X2 axis, Y2-axis shifted from 1-Y1 axis by 45 degrees
The warp yarn and the weft yarn are oriented in the fiber obliquely with respect to the Y2 axis. The mechanical properties become pseudo-isotropic by the two carbon fiber fabrics 3a and 3b of the second and fourth layers.

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

In the above description, a preform using two layers of carbon fiber fabric has been described. However, at least one layer of carbon fiber fabric may be used, and the rest may be another reinforcing fiber base material. Also, a preform using two types of reinforcing fiber base materials, ie, a continuous strand mat made of glass fiber and a carbon fiber woven fabric, has been described. Preferably, the fiber orientation by lamination is preferably such that the fiber orientation of the carbon fiber fabric is pseudo-isotropic, as described above, but is not necessarily limited. Similarly, the number of layers is not limited to the above-described four layers, but can be appropriately determined depending on the characteristics and thickness required of the molded product.

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

By carefully observing the situation where the carbon fiber woven fabric fits the mold, the carbon fiber is hardly stretched because of its high tensile modulus, and the sheet-shaped carbon fiber woven fabric is deep drawn into a hemispherical shell shape. When deformed, the part where the warp yarn (0 degree) and the weft yarn (90 degree) are fiber oriented with respect to the mold is pulled, and the part where the fiber orientation is diagonal (± 45 degrees) is the intersection angle of the woven yarn. And the woven fabric fitted to the mold. In the preform, there is a portion where the crossing angle of the yarn is 90 degrees, but the crossing angle is variously changed due to misalignment, and the crossing angle of the yarn is smaller in the preform with a higher degree of drawing. . In addition, as a result of intensive studies, it was found that the carbon fiber woven fabric 2
If the minimum intersection angle of the carbon fibers in the direction in the preform is 20 to 45 degrees as specified in the present invention, a normal deep drawn CFRP molded product, for example, a preform of a helmet cap, a housing or a speaker cone, It was found that the fabric can be produced without making a cut in the fabric.

That is, if the minimum intersection angle in the preform is 45 degrees or more, the preform for these deep drawn products is a preform having wrinkles in the fabric and a preform having no wrinkles. It is necessary to make a cut in the woven fabric in order to prevent intrusion. Further, when the minimum crossing angle is 20 degrees or less, the degree of crossing of the warp and the weft in this portion becomes severe, and when molded into FRP, the resin impregnating 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 with a large gap between the yarns and a large void formed by the woven yarn is required. This is possible if a textile fabric is used. In this case, the fiber orientation in the oblique direction is misaligned, the crossing angle of the yarn becomes smaller, and the yarn interval becomes smaller,
The voids formed by the woven yarns of the carbon fiber fabric in this portion are reduced, that is, the cover factor is increased, but the warp and the weft are oriented in the fiber with respect to the mold. Since there is no misalignment deformation, the voids formed by the woven yarn are large as in the original state of the mesh-like carbon fiber woven fabric. That is, the cover factor is small.

However, in the present invention, by using the reinforcing woven fabric using the flat and substantially twistless reinforcing fiber multifilament yarn as the woven yarn as described above, a high cover factor can be obtained without using a mesh woven fabric. Is achieved.

The cover factor of the woven carbon fiber in the preform, as described above, Ru der 85% or more. When a preform with a small cover factor of a carbon fiber fabric is molded, the surface of the FRP molded product becomes uneven, or the resin is unevenly distributed in the void formed by the woven yarn, resulting in a resin excess, and cracks occur in this portion. In addition, the voids concentrate and reduce the strength of the FRP. In addition, since carbon fibers do not exist in this portion when viewed partially, a portion having extremely low strength locally exists.

In the carbon fiber woven fabrics used for the preforms 1 and 2, the warp yarns and the weft yarns made of flat carbon fiber multifilament yarns are woven at a very coarse density, and the crimp of the woven yarns is small. , Easy to misalign the yarn. That is, when the carbon fiber fabric is misaligned and deformed, there is sufficient room to close the yarn interval of the warp or weft yarn, so that wrinkles do not occur while reducing the yarn interval while narrowing the yarn width of the flat yarn. It can be transformed. In other words, the intersection angle between the warp and the weft can be reduced, the wrinkles do not enter the carbon fiber fabric, the entire surface of the hemispherical shell-shaped preform can be integrally covered without breaks, and the physical properties are high, A deep drawn FRP molded product with little variation can be obtained.

The carbon fiber of the carbon fiber fabric used for the preform of the present invention has a single fiber diameter of 5 to 20 μm and a tensile modulus of 18 × 10 ³ kgf / mm ² measured in accordance with JIS R7601. As described above, the tensile strength is 25
For products requiring impact resistance, such as helmet caps, which have a tensile modulus of 2 kgf / mm ² or more,
0 × 10 ³ kgf / mm ² or more, and the fracture strain energy w defined by the following equation is 4.0 mm · kgf / mm ³
The high toughness carbon fibers described above are preferable. w = σ ² / 2E σ: tensile strength of carbon fiber (kgf / mm ² ) E: tensile elasticity of carbon fiber (kgf / mm ² )

The preform according to the present invention as described above is deep-drawn as follows. That is, the preform manufacturing method of the present invention has a cover factor of 85%.
The reinforced fiber multi-layer is flat and has substantially no twist.
A woven fabric using filament yarn as a woven yarn, wherein the reinforcing fiber
The multifilament yarn is a carbon fiber yarn, the carbon fiber
5,000 to 24,000 yarn filaments, fine
A reinforcing base material containing at least one bidirectional reinforcing fabric having a degree of 3,000 to 20,000 denier is inclined in a direction oblique to a direction in which a yarn orientation direction of the reinforcing fabric is directed to a center of deep drawing. And deep-drawing shaping while fixing at each corner.

The reinforcing substrate to be deep- drawn may be a raw reinforcing fabric, or at least one of the reinforcing substrates may be in the form of a prepreg.

The method for producing a preform according to the present invention comprises:
Referring to the preform shown in FIGS. 1 to 3 described above, first, the mats 4a, 4b and the carbon fiber fabrics 3a, 3b are rectangularly shaped along the warp and weft to a predetermined size larger than the surface area of the mold. Cut into squares. Next, a mat 4a serving as the first layer of the preform,
The carbon fiber woven fabric 3a serving as the second layer, the mat 4b serving as the third layer, and the carbon fiber woven fabric 3b serving as the fourth layer are arranged in the second order.
The carbon fiber fabrics 3a and 3b of the fourth layer and the fourth layer are overlapped with a shift of 45 degrees. Next, four corners of each of the second and fourth carbon fiber woven fabrics are fixed with a frame, and preferably, each of the four corners of the mat is also fixed simultaneously with the woven fabric and placed on a female mold. By pressing, deep drawing can be easily performed without wrinkling the woven fabric. Thus, the preform 1 is formed. At the same time as the shaping, the preform 2 can be easily and efficiently manufactured by cutting out the fiber base material that has been pushed to the corners by press cutting.

The fixing points at the time of the above-mentioned deep drawing are four corner points 6 and 7 where the yarn orientation direction of the carbon fiber fabrics 3a and 3b is oblique to the direction toward the deep drawing center 5. . This fixation may be completely fixed at a fixed point, but it is more preferable to apply a slight outward tension because misalignment for keeping the minimum intersection angle θ within a predetermined range is likely to occur.

When a continuous strand mat is used as a reinforcing fiber base material other than carbon fibers as described above, even when deep drawing is performed, the loop-shaped strands stretch and fit into the mold. This is preferable because the base material does not break due to shaping.

In the above-described method for producing a preform, the case where all the fiber bases are simultaneously formed has been described. However, the fiber bases may be formed one by one, and the respective fiber bases may be overlapped to form a preform. Good.

In producing a preform, a continuous strand mat fixed in form with a thermoplastic polymer binder is used as a mat, or a carbon fiber fabric to which a thermoplastic polymer binder is adhered as a reinforcing fabric. Or use a powdery, thread-like or ultra-thin nonwoven fabric as a thermoplastic polymer binder between the carbon fiber woven fabric and the mat, and heat the mold above the softening point of these thermoplastic polymers to shape them. Then, since the form of the preform taken out of the mold is stabilized, the subsequent molding becomes easy. As such a thermoplastic polymer, a polymer having a low melting point and not deteriorating the properties of FRP is preferable, and a low-melting point copolymer nylon resin or a low-melting point polyester resin is preferable. The amount is preferably as small as possible, and is about 0.5 to 5% by weight based on the fiber weight of the preform.

As described above, a prepreg obtained by impregnating a carbon fiber fabric or the like with a B-stage thermosetting matrix resin in advance can 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, using the preform manufactured as described above, the FRP according to the present invention is molded. In this FRP, a thermosetting resin or a thermoplastic resin can be used as the matrix resin. Matrix resin, its tensile elongation at break is preferably larger than the tensile elongation at break of the woven yarn of the reinforcing fabric, and as the matrix resin,
It is preferable to use 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%.

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 in the B stage when impregnated in the fabric. Also, 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-described preform is manufactured in a heated female mold, a measured amount of a liquid thermosetting resin containing a curing agent is put in the female mold, and then the heated preform is molded in a heated male mold. Pressing allows easy molding.

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

In the deep drawn FRP molded product such as a helmet cap, a housing, and a speaker cone according to the present invention, in a preform for molding a fiber-reinforced resin including at least one layer of a reinforcing fabric, the carbon fiber constituting the fabric is preferably used. The minimum intersection angle is between 20 and 45 degrees. In the form of a preform, the woven fabric can be integrated without a break, and the cover factor in each part can be 85% or more.

Such an FRP molded product is a deep drawn product, but the warp and weft of the reinforcing fabric are not cut, wrinkles are not formed, and the cover factor is large. Good, with little variation. Therefore, a lightweight and highly reliable product can be obtained.

In addition, since at least one layer of the reinforcing fabric in the deep drawn FRP molded product has continuous reinforcing fibers throughout the molded product without any breakage, even if it is a chopped strand mat of short fiber type, Although it is a continuous fiber, a molded article having good impact resistance can be obtained even when used in combination with a continuous strand mat in which strands are arranged while drawing a loop.

[0063]

Preferred embodiments of the present invention will be described below. Example 1 A flat carbon fiber having a yarn width of 6.5 mm and a yarn thickness of 0.12 mm (“Treca” T700SC-12K manufactured by Toray Industries, Inc.)
(Fineness: 7,200 deniers)), weaving the warp and weft yarns in a plain weave structure with a weave density of 1.25 yarns / cm and a flat shape to obtain a woven fabric having a basis weight of 200 g / m ^2. Was. The cover factor of the obtained woven fabric is 99
% And voids between the yarns.

Next, four woven fabrics cut into a 60 cm square with the weaving yarn direction as one side are prepared, the centers of the cut woven pieces are aligned, and the weaving yarn angle is (0 °, 90 °) / (± 45 °).
°) / (± 45 °) / (0 °, 90 °).

Then, the laminated fabric base material is placed on a female mold molded from a helmet, and the corners where the weave yarn orientation direction of each fabric is oblique to the direction toward the deep drawing center are fixed. Then, a male mold was pressed from above and shaped.

The preform obtained by the above method was shaped according to the helmet pattern and without wrinkles. Further, the cover factor of the preform was 98%, which was very small and had very few voids, and was smooth. In addition, the bias direction of each fabric in the preform was elongated, and the minimum intersection angle of the woven yarn was greatly sheared as 40 degrees.

The preform was impregnated with a thermosetting vinyl ester resin using a molding die to obtain a molded product. The obtained molded product maintained a high cover factor in the preform, had no uneven distribution of the resin, had a uniform distribution of carbon fibers, and had a smooth surface. In addition, even 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)
The shapeability was evaluated in the same manner as in Example 1 above for 200 g / m ² basis weight woven fabric having a plain weave structure and 0 denier. In the obtained preform, wrinkles occurred in the bias direction of each cut fabric at the edge of the helmet. Further, the weave yarn intersection 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, each woven yarn approaches the stretch in the bias direction and is constrained to be wrinkled due to a limit.

The preform was molded in the same manner as in the example, but could not be molded to the set thickness because of the presence of wrinkles, and was thick. Due to such a situation, there are many places where the resin is insufficient and the resin is missing, and the product has an uneven surface.

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 woven yarn density of 3 yarns / cm was produced and compared. The fabric weight is 120 g / m ²
And the cover factor was as coarse as 80%.

The fabric obtained was evaluated for formability in the same manner as in Example 1. No wrinkles were found on the shaped preform, but the binding of the yarn was very weak.
During shaping, the yarn was misaligned. Also,
At the top of the helmet that was not sheared, there was no misalignment, but the eyes were open because the cover factor remained the same as that of the original fabric.

The preform was molded in the same manner as in Example 1. The obtained molded product was a non-uniform product in which the misalignment and low cover factor observed in the preform appeared as they were, and the resin was unevenly distributed in the misalignment portions and the gaps between the yarns. The portion where the resin was unevenly distributed was depressed due to the shrinkage of the resin upon curing, and was a product having poor surface smoothness. As described above, although the open woven fabric is easily sheared, there is a problem in that misalignment occurs and there are vacant portions, which cannot be used for fiber-reinforced plastics that require reliability.

[0074]

As described above, the preform of the present invention and the deep drawn product of the preform of the present invention are deep drawn since the minimum crossing angle of the reinforcing woven fabric yarn in the preform was specified. However, since the reinforcing fabric has no cuts and no wrinkles and has a large cover factor, a lightweight and highly reliable FRP product can be obtained.

Further, since at least one layer of the reinforcing woven fabric has no break and carbon fibers are continuously contained in the whole molded product, even if it is a chopped strand mat of short fiber type or continuous fiber, Even when used in combination with a continuous strand mat in which strands are arranged while drawing a loop, a molded article having good impact resistance can be obtained.

Further, according to the preform manufacturing method of the present invention, a desired deep-drawn preform is formed by simply fixing each corner of the woven fabric. Since the product is molded, the productivity is good.

[Brief description of the drawings]

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

FIG. 2 is a longitudinal sectional view of the preform in which a peripheral edge of the preform of FIG. 1 is cut and removed.

FIG. 3 is a schematic plan view of the preform of FIG. 1;

[Explanation of symbols]

 1, 2 Preform 1a, 2a Convex portion (deep drawn portion) 3a, 3b Reinforced woven fabric (carbon fiber woven fabric) 4a, 4b Mat 5 Deep drawn center 6, 7 Fixed portion θ Minimum intersection angle

Continuation of front page (56) References JP-A-63-152637 (JP, A) JP-A-5-220853 (JP, A) JP-A-6-31823 (JP, A) JP-A-4-294136 (JP) JP-A-7-243147 (JP, A) JP-A-7-118988 (JP, A) Japanese Utility Model Application Laid-Open 63-187496 (JP, U) Japanese Utility Model Application Laid-open No. 2-38442 (JP, U) 59-47520 (JP, B2) (58) Fields investigated (Int. Cl. ⁷ , DB name) B29B 11/16 B32B 5/02 C08J 5/24 D03D 1/00 D03D 15/00

Claims (11)

(57) [Claims] (1) The cover factor is 85% or more.
Includes a directional reinforcement fabric, Ri minimum intersection angle is 20 to 45 degrees der of yarns extending in the two directions of the reinforcing fabric, the reinforcing fabric
Reinforced fiber multifilament that is flat and has virtually no twist
The reinforced fiber multifilament comprising a woven yarn
The filament yarn is a carbon fiber yarn, and the filament of the carbon fiber yarn is
The number of contacts is 5,000 to 24,000, and the fineness is 3,000.
A deep-drawn preform having a denier of 0 to 20,000 . 2. The reinforcing fabric according to claim 1, wherein the reinforcing fabric is continuous.
Preform. 3. The multifilament yarn of the reinforcing fiber.
Thickness is 0.05-0.2mm, yarn width / thickness ratio is 30 or more
The preform of claim 1 or 2, wherein the preform is on. 4. The reinforcing fabric according to claim 1, wherein the reinforcing fabric comprises the reinforcing fiber multifilament.
A woven fabric having a warp yarn and a weft yarn as a lament yarn,
The fabric thickness is 0.07 to 0.4 mm, and the fabric weight is 100 to
It is 300 g / m ^2, preform according to any one of claims 1 to 3. 5. The method according to claim 1, wherein the reinforcing fabric has a flat structure.
Item 5. The preform according to any one of Items 1 to 4 . 6. A mat comprising the reinforcing fabric and a reinforcing fiber.
The preform according to any one of claims 1 to 5, wherein is laminated . 7. The method according to claim 7, wherein the binder of the thermoplastic polymer adheres.
And the amount of adhesion is relative to the fiber weight of the preform.
The preform according to any one of claims 1 to 6, which is in a range of 0.5 to 5% by weight . 8. The multi-filament yarn for reinforcing fibers according to claim 8, wherein
Made of elementary fiber yarn, wherein the fabric weight and the carbon fiber yarn
Satisfies the following relationship and the cover factor is
The reinforcing fabric for a preform according to claim 4 , which is 95% or more . W = k · D ^1/2 where W: fabric weight (g / m ² ) k: proportionality constant (1.4 to 3.6) D: fineness of carbon fiber yarn (denier) 9. The method according to claim 8, wherein the cover factor is 85% or more.
Reinforced fiber multifilament that is flat and has virtually no twist
The reinforced fiber multifilament comprising a woven yarn
The filament yarn is a carbon fiber yarn, and the filament of the carbon fiber yarn is
The number of contacts is 5,000 to 24,000, and the fineness is 3,000.
Includes bidirectional reinforced fabric from 0 to 20,000 denier
The direction of the yarn of the reinforcing fabric is the center of deep drawing.
At each corner that is diagonal to the direction facing
Manufacture of preforms characterized by deep drawing
Method. 10. The reinforcing base material is in the form of a prepreg.
The method for producing a preform according to claim 9, wherein: 11. The method according to claim 1 , wherein
Fiber reinforced plastic molded using preform
H.