JPH11107107A - Carbon fiber woven fabric and fiber-reinforced plastic and molding of fiber-reinforced plastic - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain an inexpensive carbon fiber woven fabric large in carbon fiber metsuke (a weight unit of cloth), excellent in resin flowability and permeability on molding, and giving molded products excellent in mechanical characteristics. SOLUTION: This unidirectional carbon fiber woven fabric comprises tow-like carbon fiber yarns 2 each having filament number of 40,000-4000,000 and has spaces between the carbon fiber yarns. The carbon fiber yarns are arranged in the warp direction, and auxiliary yarns are arranged in the weft directions.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a woven fabric made of carbon fibers, and more particularly to a carbon fiber woven fabric made of thick tow-like carbon fiber yarns and a method of molding fiber-reinforced plastic using the same.

[0002]

2. Description of the Related Art Carbon fiber has a low specific gravity, a high tensile strength and a high tensile modulus, and carbon fiber reinforced plastic (hereinafter referred to as CFRP) obtained by solidifying the resin with resin has a high specific strength and a high specific modulus. And is called an advanced composite material.

However, the conventional CFRP is composed of, for example, 3,000 filaments of fine carbon fiber yarns, and the carbon fiber yarns are arranged in the vertical direction and the horizontal direction, and have a carbon fiber weight of 200 to 400 g / m ² . Since a thin bidirectional fabric is manufactured by laminating a large number of prepregs impregnated with resin in advance and molding it by autoclaving, the manufacturing cost is high and the performance is excellent in the following situations, but its development field is Is limited to aircraft-related structural materials and premium sports equipment such as premium products, and has been difficult to deploy in general industrial fields.

A. Fine carbon fiber yarns reduce the productivity of carbon fibers.

B. Since the woven fabric is manufactured with thin yarns, the productivity of the woven fabric is low.

C. Since the woven fabric is thin, laminating a predetermined amount of carbon fibers requires a large number of laminations, which increases labor for lamination.

D. Since a prepreg process is required, a processing cost of the prepreg is added.

E. An autoclave is required, and a large capital investment is required.

In particular, in order to reduce the cost of large molded products, there is a resin transfer molding method in which conventional carbon fiber fabrics are laminated in a molding die and a room temperature curing resin is injected under pressure. A so-called vacuum bag molding method is known in which these are laminated on a mold, covered with a bag film, a vacuum state is formed in the inside, and a room temperature-curable resin is injected. This method significantly reduces the cost of CFRP according to D and E above, but A, B and C make the molded CFRP product expensive.

On the other hand, it is conceivable to use a carbon fiber woven fabric having a large basis weight of carbon fiber using a conventional carbon fiber thread, but it has hardly been put into practical use due to the following problems.

F. A two-way woven fabric in which carbon fibers are arranged in two directions, the warp direction and the weft direction, makes it possible to obtain a woven fabric having a large carbon fiber basis weight. However, since the warp yarn and the weft yarn intersect, the weaving yarn crimp increases. F
When RP is used, strength and elastic modulus are reduced due to stress concentration.

G. Although the woven fabric arranged in one direction does not cause a decrease in strength due to crimping, since the carbon fiber yarns are arranged only in one direction, if the basis weight of the woven fabric is increased,
Since the fiber density increases and the fibers are densely packed, the resin flow deteriorates in molding methods such as resin transfer molding and vacuum bag molding. Impregnating property of the resin becomes worse.

[0013]

The present invention focuses on such a situation, and the woven fabric has a large basis weight of carbon fiber, but has excellent fluidity and impregnation of resin at the time of molding, and has good mechanical properties at the time of molding. To provide an inexpensive carbon fiber woven fabric having excellent mechanical properties. Another object of the present invention is to provide an inexpensive fiber-reinforced plastic having excellent mechanical properties using the carbon fiber fabric. Another object of the present invention is to provide a method for molding a fiber-reinforced plastic (hereinafter, referred to as FRP) using the woven fabric.

[0014]

In order to achieve the above object, the present invention basically has the following arrangement. That is,
It is composed of tow-like carbon fiber yarns, the number of filaments of the carbon fiber yarns is 40,000 to 400,000, the carbon fiber yarns are arranged in the warp direction, and the auxiliary yarns are arranged in the weft direction. A unidirectional carbon fiber woven fabric having a gap between carbon fiber yarns.

[0015]

BEST MODE FOR CARRYING OUT THE INVENTION The carbon fiber yarn used in the present invention is preferably formed in a tow-like shape by bundling 40,000 to 400,000 multifilaments having a single fiber diameter of 5 to 15 microns. The carbon fiber yarn has a fineness of 25,000 to 350,000 denier.

The number of filaments of the carbon fiber yarn is 40,0.
When the fineness of the yarn is less than or equal to 25,000 deniers, the yarn becomes relatively thin, so that the carbon fiber constituting the yarn is preferably impregnated with the resin. Thin. Therefore, if the basis weight of the carbon fiber fabric is increased, the number of carbon fiber yarns to be used increases, and it becomes difficult to provide a gap between the carbon fiber yarns. In a molding method such as resin transfer molding or vacuum bag molding, resin is used. Flow becomes worse. Further, it is not expected that the cost of the carbon fiber yarn is reduced so much. On the other hand, the number of filaments of the carbon fiber yarn is 400,000 or more, and the fineness of the yarn is 350,
If the denier is 000 denier or more, the carbon fiber yarn becomes inexpensive, and the thickness of the yarn increases, so that even if the basis weight of the carbon fiber woven fabric is increased, it is possible to provide a gap between the carbon fiber yarns. Since the yarn becomes thicker, the distance to the center of the yarn is increased, and impregnation of the resin that advances from the periphery of the yarn becomes incomplete. The number of filaments is 40,000-40
000 fibers, fineness of carbon fiber yarn is 25,000-3
50,000 denier, more preferably the number of filaments of carbon fiber yarn is 40,000 to 100,000,
When the yarn fineness is 30,000 to 70,000 denier, a gap can be provided between the carbon fiber yarns.
The resin flows through resin transfer molding and vacuum bag molding, and even if the laminate becomes thicker, the resin can be quickly spread throughout the entire body, and the impregnation of the resin that progresses from around the yarn can be completed. is there.

The gap between yarns in the carbon fiber fabric of the present invention is preferably 0.2 to 2 mm. 2mm gap between yarns
With the above, since the weft is thin in the unidirectional woven fabric, the draping property of the woven fabric is increased, and the woven fabric becomes soft and difficult to handle. Further, since no fiber exists in the gap, F
When RP is used, the surface of the FRP becomes uneven due to shrinkage of the resin during curing. On the other hand, if the gap between the yarns is 0.2 mm or less, the flow resistance of the resin into the gap between the yarns increases, and the resin injection speed into the fibrous base material laminate decreases.

When the gap between the yarns is 0.2 to 2 mm, when resin is injected into a fiber base material sealed in a mold or bag film, such as resin transfer molding or vacuum bag molding, molding is performed. The gap between the yarns serves as a resin flow path, which reduces the time for injecting the resin and leads to more efficient molding.

Such a carbon fiber thread can be produced, for example, by subjecting a tow of polyacrylonitrile fiber to flame resistance and carbonization, and then attaching a sizing agent and bunching. Because tow can be manufactured as a thick thread, polyacrylonitrile fiber and flame-resistant,
It is possible to improve the productivity in the process of producing carbonized carbon fibers and to produce inexpensive carbon fiber yarns.

Further, the carbon fiber of the present invention is JIS R7
The tensile strength according to the 601 method is 3 to 4 GPa, the tensile modulus is about 200 to 300 GPa, and it is preferable to attach a sizing agent of about 0.5 to 2% by weight in order to improve the weaving operation in the fabric manufacturing process. In addition, if the carbon fiber yarns constituting the woven fabric are twisted, impregnation with the resin is hindered at the convergence portion of the carbon fiber bundle due to the twisting.

In the present invention, if the carbon fibers constituting the yarn are entangled with each other, a gap can be provided between the carbon fibers by the intersection or entanglement of the carbon fibers. This is preferable because it becomes bulky and makes it easy to impregnate the resin into the carbon fiber thread of the woven fabric. The degree of entanglement of this carbon fiber can be represented by a hook drop value, and the degree of entanglement with a hook drop value FD ₍₁₅₎ of 30 cm or less is preferable. Hook drop value FD ₍₁₅₎ is 30c
If it is more than m, the degree of entanglement of the fibers is small, and the impregnation of the resin is not improved. If the hook drop value FD ₍₁₅₎ is 2 cm or less, the entanglement of the carbon fiber becomes large, the carbon fiber thread and the fabric become bulky, the gap between the carbon fibers increases, and the resin is easily impregnated. Since the bending of the fiber becomes large, when FRP is used, stress concentration occurs, and the strength is reduced. Hook drop value is in the range of 2 to 30 cm, more preferably 2 to 10 cm
Within the range, a suitable resin impregnation property is given.
High strength when RP is used.

However, the hook drop value is merely an index for indicating the degree of confounding. Even if it is difficult or impossible to directly measure the hook drop value, the hook drop value is measured by other measuring means and the value is measured. Is converted into a hook drop value by an appropriate method, and the value may be within the above numerical range.

The hook drop value FD ₍₁₅₎ indicates the degree of entanglement of the fibers of the carbon fiber yarn constituting the woven fabric.
It can be represented by the free fall distance of the metal hook measured by the measuring device shown in FIGS.

When the sizing agent is attached to the carbon fiber yarn, the free fall distance of the metal hook is affected by the amount and state of the sizing agent attached. Perform this measurement. For example, the sizing agent can be removed by heat treatment in a nitrogen atmosphere at 700 ° C. for one hour.

Also, when the prepreg or CFRP resin adheres to or impregnates the carbon fiber thread, the free fall distance of the metal hook is affected or almost no measurement is possible. Perform this measurement after removal. For example, 700 ° C for vinyl ester resin
Can be removed by performing a heat treatment in a nitrogen atmosphere for 5 hours.

Hook drop value F of carbon fiber yarn of woven fabric
D ₍₁₅₎ extracts three woven fabrics having a width of 1,000 mm and a length of 1,000 mm, and loosens the warp yarns from each woven fabric so as not to generate fluff and to prevent twisting, A carbon fiber thread having a length of 1,000 mm is collected. A desizing process is performed so that the fiber arrangement state of the loosened carbon fiber yarn is not disturbed,
Fix the device with. Since the width of the fixed yarn, that is, the thickness of the yarn, affects the hook drop value, the relationship between the width B (mm) of the fixed yarn and the yarn fineness D (denier) is determined according to the following equation. Then, the upper clamp 104 was fixed so that the thickness of the yarn became uniform.

Next, with a load of 4 mg / denier applied to the lower end, the width B = 4 × 10 ⁻⁴ × D
In order to prevent twisting, the lower clamp 105 is used to fix the grip vertically in the vertical direction so that the grip distance is 950 mm.

Next, the carbon fiber yarn 10 with the upper and lower ends fixed
In the center in the width direction of No. 1, a weight 103 with a cotton thread 106 is attached to a metal hook 102 (wire diameter: 1 mm, radius: 5 mm).
Weight (from the upper end of the hook 102 to the weight 103)
Distance to the top of the metal: 30 mm) its metal hook 102
Is hooked so that the distance from the lower end of the upper clamp to the upper end of the metal hook 102 becomes 50 mm, and then release the hand to allow the free fall distance of the metal hook 102 (from the above 50 mm position to the upper end of the metal hook 102 at the drop position). Distance). The weight of the metal hook 102 and the cotton thread 106 is reduced as much as possible, and the total weight of the metal hook 102, the cotton thread 106 and the weight 103, that is, the weight of the weight is 15 g.
So that The hook drop value FD ₍₁₅₎ is
Ten measurements were made on the warp yarn of one woven fabric and n =
It is represented by an average value of 30. Although the metal hook 102 may fall to the position of the lower clamp 105, the free fall distance at that time is considered to be 900 mm.
For that purpose, the metal hook 102 is attached to the lower clamp 105.
However, it is necessary to prevent the cotton thread 106 and the weight 103 from being caught, and it is necessary to provide a sufficient space below the lower clamp 105 as shown in FIG. The measurement was carried out at a temperature of 25 ° C.
After leaving for 24 hours in an environment at a temperature of 60 ° C. and a relative humidity of 60%, the process is performed in an environment of a temperature of 25 ° C. and a relative humidity of 60%.

The carbon fiber fabric of the present invention preferably has a bulk density of 0.65 g / cm ³ or less. When the bulk density is 0.65 g / cm ³ or less, the carbon fiber thread and the woven fabric become bulky, the gap between the carbon fibers increases, and the resin is easily impregnated. Resin impregnation is possible even in lay-up molding.

In the present invention, the bulk density V means a value calculated by the following formula.

V = w / (t × A) where t: thickness of fabric (cm) A: area of fabric (cm ² ) w: weight of carbon fiber in area A of fabric (g) The measuring method of the thickness is JIS R 7602
The thickness measuring device described in Section 5.6 complies with the dial gauge method. However, the load was set to 3 kPa, five woven fabrics were superimposed, the value 20 seconds after the load was applied was read, and the value was divided by the number of woven fabrics to obtain the thickness per one fabric. In addition, in order to minimize the influence of the weft yarn as the auxiliary yarn on the thickness of the woven fabric, the woven fabrics were overlapped so that the positions of the weft yarns of the woven fabric to be overlapped were shifted from each other.

A specific embodiment of the present invention will be described with reference to the drawings. FIG. 1 shows a unidirectional carbon fiber woven fabric according to an embodiment of the present invention. In the drawing, reference numeral 2 denotes a carbon fiber yarn, and a large number of carbon fiber yarns are arranged in parallel in the warp direction, This is a so-called unidirectional woven fabric in which the auxiliary yarns 3 in the weft direction are interlaced with the carbon fiber yarns.

FIG. 2 shows another embodiment of the carbon fiber woven fabric of the present invention, in which the carbon fiber yarns 2 having substantially no bending in the warp direction are unidirectionally parallel to each other and in a sheet form. The yarn group d of the weft auxiliary yarn 3 is located on both sides of the sheet surface of the yarn group b which is aligned with the weft yarn auxiliary yarn group,
This is a unidirectional carbon fiber woven fabric in which the yarn group C of the warp direction auxiliary yarn 4 parallel to the carbon fiber yarn group forms a weave structure and integrally holds the yarn group. Since such a woven fabric has no bending in the warp direction carbon fiber thread, it is molded and CFRP.
Even so, stress does not concentrate and high strength is obtained.

The auxiliary yarn used in the present invention is essentially F
Since it is not used to bear the load when it becomes RP, it is used for maintaining the form of the woven fabric.
Yarns of about 000 denier and finer than carbon fiber yarns are preferred. In particular, 100-500 denier, extremely thin compared to carbon fiber yarn, and weft yarn density of 0.5-8
When the number is about book / cm, the restraint of the carbon fiber thread by the auxiliary yarn of the weft becomes weak, so that a bulky woven fabric is obtained. In addition,
The auxiliary yarn preferably has a dry heat shrinkage at 150 ° C. of 0.1% or less from the viewpoint of dimensional stability of the woven fabric and prevention of shrinkage due to heating at the time of staple treatment. Fibers constituting such an auxiliary yarn include carbon fiber, glass fiber, polyaramid fiber and the like.

In the above unidirectional woven fabric, if the basis weight of the carbon fiber is about 400 to 1,500 g / m ² , the number of laminations may be small, so that the labor for laminating the fiber base material during molding is reduced. This leads to labor saving in molding. When the basis weight of the carbon fiber is about 400 to 700 g / m ² , the woven fabric is moderately soft and the woven fabric weight is relatively light, so that the woven fabric can follow a complicated shape such as a corner in lamination. However, it is possible to sufficiently impregnate the resin with a normal temperature-curable resin having a resin viscosity of 2 to 7 poise by using an impregnating roller in usual hand lay-up molding.

Since the carbon fiber woven fabric of the present invention has a thick carbon fiber yarn, the number of yarns constituting the woven fabric is reduced.
Therefore, the number of crossing points with the weft yarns is reduced, and the carbon fiber yarns are frayed at the time of cutting, resulting in poor workability.

Therefore, in the unidirectional carbon fiber woven fabric of the present invention, as shown in FIGS. 1 and 2, the low melting point polymer 5 extending linearly or dotwise in the length direction of the weft auxiliary yarn is used. It is preferable that the low-melting polymer is a so-called blind woven fabric in which the low-melting polymer is adhered at the intersection of the yarns orthogonal to each other, that is, the warp-direction carbon fiber yarns and the warp-direction auxiliary yarns. 1 and 2 show an example in which the low-melting polymer adheres to the weft-direction auxiliary yarn, but may be attached to the warp-direction carbon fiber yarn and / or the warp-direction auxiliary yarn. Alternatively, it may be attached to the warp direction carbon fiber yarn and / or the warp direction auxiliary yarn and the weft direction auxiliary yarn.

The woven fabric thus obtained is made of resin
In transfer molding, vacuum bag molding, and the like, the fabric is cut and laminated into a mold. At the time of cutting, fraying of the yarn can be prevented, and the workability of forming is greatly improved.

The amount of the low-melting polymer adhered is preferably 6 g / m ² or less, since a large amount impairs resin impregnation or lowers the mechanical properties of CFRP. However, 0.5
When the amount is less than g / m ² , the effect of the eye is weakened.
~6g / m ² is preferred.

In the case of a unidirectional carbon fiber woven fabric, if a large amount of these low-melting polymers adhere to a thin auxiliary yarn, the auxiliary yarn basically does not support reinforcement, but the starting point of destruction starts from the auxiliary yarn. To prevent these, the amount of the low-melting polymer adhered is preferably 40% by weight or less of the auxiliary yarn.

The low melting point polymer used in the present invention is usually
It is selected from nylon, copolymer nylon, polyester, copolymer polyester, vinylidene chloride, vinyl chloride, and polyurethane. Among them, copolymerized nylon is particularly preferably used because the polymer can be melted at a low temperature, the adhesive strength is strong, and the expected effect can be obtained with a small amount of use.

The fiber-reinforced plastic of the present invention may be a fiber-reinforced plastic in which all of the reinforcing fiber bases are formed by laminating the carbon fiber fabric of the present invention in a single layer or in multiple layers and impregnated with a resin. At least one layer of the fiber substrate is the carbon fiber fabric of the present invention, and can be combined with a substrate made of another reinforcing fiber such as glass fiber or polyaramid fiber.

The resin used for the fiber reinforced plastic of the present invention includes, for example, thermosetting resins such as epoxy resin, unsaturated polyester resin, vinyl ester resin and phenol resin, nylon resin, polyester resin, ABS resin, polyethylene resin and polypropylene resin. And thermoplastic resins such as polyvinyl chloride resin, polyether ether ketone resin and polyphenylene sulfide resin.

The fiber reinforced plastic of the present invention uses a carbon fiber woven fabric in which the fiber base is made of a thick tow-like yarn and has a high basis weight but has a gap between the carbon fiber yarns. In this case, the resin has good fluidity and impregnating property, is excellent in mechanical properties, and is inexpensive.

A specific embodiment of the present invention will be described with reference to the drawings. FIG. 1 shows a unidirectional carbon fiber woven fabric according to an embodiment of the present invention. In the drawing, reference numeral 2 denotes a carbon fiber yarn, and a large number of carbon fiber yarns are arranged in parallel in the warp direction, This is a so-called unidirectional woven fabric in which the auxiliary yarns 3 in the weft direction are interlaced with the carbon fiber yarns.

FIG. 2 shows another embodiment of the carbon fiber woven fabric of the present invention. In the warp direction, the carbon fiber yarns 2 having substantially no bending (crimp) are unidirectionally parallel to each other. In addition, the yarn group d of the weft auxiliary yarn 3 is located on both sides of the sheet surface of the yarn group B aligned in a sheet shape, and the weft auxiliary yarn group and the warp direction auxiliary yarn parallel to the carbon fiber yarn group. 4 is a unidirectional carbon fiber woven fabric in which the yarn group C has a woven structure and holds the yarn group integrally. Since such a woven fabric does not have a crimp on the carbon fiber thread in the warp direction, stress is not concentrated even when it is molded and CFRP, and high strength is obtained.

The auxiliary yarn used in the present invention is essentially F
Since it is not used to bear the load when it becomes RP, it is used for maintaining the form of the woven fabric.
Yarns of about 000 denier and finer than carbon fiber yarns are preferred. In particular, 100-500 denier, extremely thin compared to carbon fiber yarn, and weft yarn density of 0.5-8
When the number is about book / cm, the restraint of the carbon fiber thread by the auxiliary yarn of the weft becomes weak, so that a bulky woven fabric is obtained. In addition,
The auxiliary yarn preferably has a dry heat shrinkage at 150 ° C. of 0.1% or less from the viewpoint of dimensional stability of the woven fabric and prevention of shrinkage due to heating at the time of staple treatment. Fibers constituting such an auxiliary yarn include carbon fiber, glass fiber, polyaramid fiber and the like.

In the above unidirectional woven fabric, if the basis weight of the carbon fibers is about 400 to 2,000 g / m ² , the number of laminations may be small, so that the labor of laminating the fiber base material during molding is reduced. At the time of molding, the gap between the yarns serves as a resin flow path, shortens the resin injection time, and leads to more efficient molding.

The fabric of the present invention can be used to form FRP by a conventionally known method. Among them, the resin transfer molding method and the vacuum bag molding method allow a large molded product to be produced at low cost. Since it can be used, it is preferably used.

FIG. 3 is a cross-sectional view of an embodiment for explaining a method of forming an FRP according to the present invention. In FIG. 3, a predetermined number of carbon fiber fabrics 7 of the present invention as a fiber base material are laminated on a mold 6 in a predetermined direction, and a sheet which is peeled off after the resin is cured, which is a so-called peel ply. 8 are laminated, and a medium 9 for diffusing the resin over the entire surface of the fiber base material is placed thereon. Around the fiber substrate, a porous material such as woven fabric is laminated and stretched as an edge breather 11 to which an air suction port 10 of a vacuum pump is attached, and the whole is covered with a bag film 12. The periphery of the bag / film is adhered to the mold with a butyl rubber-based or silicone rubber-based sealant 13 to prevent leakage. A discharge port 14 for the resin to be injected from the resin tank is attached to the upper part of the bag film, and the resin film is bonded with a sealant 13 so that air does not leak from a mounting portion of the discharge port. The resin tank is filled with a thermosetting resin in a syrup at room temperature containing a predetermined amount of a curing agent. Then, after the interior including the fiber base material covered with the bag film is evacuated to a vacuum pressure of about 700 to 760 Torr by a vacuum pump, the valve 15 is opened to inject the resin.
Since the inside covered with the bag film is in a vacuum state and the flow resistance of the resin is smaller in the surface direction of the medium than in the thickness direction of the fiber base material, the resin first spreads over the entire surface of the medium, and then the fiber base material Impregnation in the thickness direction proceeds. According to this method, the distance over which the resin must flow may be the thickness of the fiber base material laminate, so that the resin impregnation is completed very quickly. Preferably, the vacuum pump is operated at least until the impregnation of the resin is completed, and the inside of the bag film is kept in a vacuum state. After completion of the resin impregnation, the valve is closed and left at room temperature to cure the resin. After the resin is cured, the peel ply is peeled off, the medium, the bag and the film are removed, and the FRP molded article is obtained by removing the mold from the mold.

FIG. 4 shows an example of the medium 9 used in the present invention. The medium transmits the vacuum pressure in the bag to the fiber base material.
In addition, the resin to be injected is made to spread over the entire upper surface of the fiber base material on the medium side through the gap of the medium. That is, when the resin is injected into the medium located between the bag film and the peel ply, in FIG. 4, the injected resin flows through the gap between the bars 16 in the group A in contact with the bag film, and Since the resin flows through the gap between the bars 17 having a rectangular cross section and flows in the direction of the bars 17, the resin is diffused over the entire surface. Further, since the force applied to the bar 16 can be transmitted to the bar 17, the vacuum pressure can be transmitted to the fiber base material. The thickness of the bar is not particularly limited, but is preferably 0.2 to 2 mm. Further, the width of the gap is preferably 0.2 to 2 cm. Specific examples of the medium include polypropylene, polyethylene, polyester, polyvinyl chloride, and a mesh sheet made of metal, such as a mesh resin film, a woven fabric,
It is a net-like or knitted fabric, and several of these can be used as needed.

Although the above description has been made on the case where the medium is placed on one surface of the upper surface of the fiber base laminate, when the fiber base laminate is thick, the medium is placed on the lower surface and the upper surface of the fiber base laminate. Alternatively, resin impregnation can be performed from both sides of the fiber base laminate.

Although the molding method described above falls broadly in the category of the vacuum bag molding method, it differs from the conventional vacuum bag molding method in that the resin is diffused over the entire surface of the fiber base material laminate at the same time as the resin is injected. Differently, it is particularly suitable for use in molding large FRP molded articles.

[0054] Further, on a molding material having a groove serving as a resin flow path on the surface thereof, it is laminated so as to be in contact with the fiber base material, further covered entirely with a back film, and then covered with the back film. Is vacuumed, the resin is diffused from the groove of the molding material in contact with the fiber base material, and the fiber base material and the molding material are integrated while impregnating the laminated fiber base material with the room-temperature curing type thermosetting resin. It can also be done. According to this method, a sandwich structure using FRP as a skin material and a plate-like plate as a core material can be easily formed. According to this method, a fiber-reinforced plastic structure integrated with a plate-like plate using FRP as a skin material can be easily formed. FIG. 8 is a cross-sectional view illustrating a method of forming an FRP according to the present invention. In FIG. 8, a required number of blocks 19 in which a predetermined number of carbon fiber woven fabrics 7 as a fiber base material are wound around a molding material 18 are arranged on a mold 6, and the whole is covered with a bag film 12, and air is released. The periphery of the bag film is adhered to the mold 6 with a sealing material 13 so as not to leak. FIG. 9 shows an example of the molding material. Grooves 20 serving as resin flow paths are provided on the upper surface C, the lower surface D, the side surface E, and the front surface F of the molding material.

When the interior covered with the bag film is evacuated from the suction port with a vacuum pump and the resin is poured from the discharge port, the resin flows from the grooves with small flow resistance provided on the upper and lower surfaces and side surfaces of the molding material. All over the molding material,
After that, the fiber base material is impregnated with the resin.

Then, when the resin cures at room temperature, the groove of the molding material is filled with the matrix resin, and the groove of the molding material and the matrix resin adhere to each other. At the same time, the fiber-reinforced plastic and the matrix resin adhere to each other. A reinforced plastic structure is obtained.

According to the fiber-reinforced plastic structure of the present invention, the bonding between the fiber-reinforced plastic and the molding material is not limited to the mere fiber-reinforced plastic and the molding material surface, but also the groove of the molding material and the matrix resin. The area is increased, and the integration of the fiber-reinforced plastic and the molding material becomes strong.

The cross-sectional shape of the groove of the molding material is rectangular, trapezoidal, hemispherical, or the like, and these cross-sectional shapes and cross-sectional dimensions can be appropriately determined depending on the fluidity of the resin and the degree of adhesion between the fiber-reinforced plastic and the molding material. . Above all, if you make the trapezoid so that the cross-sectional shape becomes a wedge shape for the molding material,
The bonding between the fiber reinforced plastic and the molding material becomes stronger.

The molding material used in the present invention is preferably used if it is an organic or inorganic foam, since the resulting molded body becomes lighter. However, a non-foamed resin plate or inorganic plate, or It may be a metal plate or wood. Organic or inorganic foams include polyurethane, polystyrene, polyethylene, polypropylene, PVC,
Examples include foams of silicone, isocyanurate, phenol, and acrylic resin, lightweight cellular concrete, calcium silicate foam and calcium carbonate foam.

The compression strength of the molding material is 1.0 kgf
/ Cm ² or more is preferred. Compressive strength is 1.0kgf / c
If it is less than m ² , the vacuum pressure is reduced during vacuum bagging during molding, and the molded material is crushed, which is not preferable.

Although the carbon fiber woven fabric of the present invention has a large fiber basis weight per sheet, there is a gap between the carbon fiber yarns of the woven fabric. Since the resin spreads over the entire surface in the surface direction of the fiber base laminate, resin impregnation proceeds in the thickness direction of the fiber base laminate,
Not only the labor for lamination is reduced, but also the impregnation of the resin is completely performed, and the time for injecting the resin is reduced, so that the workability is improved.

The fiber base material used in the present invention does not need to be all the carbon fiber fabric of the present invention, and may be used in at least one layer. The other fibrous base material may be, for example, a normal carbon fiber woven fabric, or another reinforced fiber, for example, a woven fabric made of glass fiber or polyaramid fiber, a chopped strand mat, or a continuous strand mat. Sheets in which these reinforcing fiber yarns are arranged in parallel are laminated at 0 ° (length direction of the fiber base), 90 ° (width direction of the fiber base) or ± 45 ° (diagonal direction of the fiber base), This may be a multiaxial stitched fabric sewn with a stitch thread such as glass fiber, polyester fiber, or polyaramid fiber.

In particular, when the combination of the fiber base material is the unidirectional carbon fiber fabric of the present invention and the multiaxial stitch fabric,
When a unidirectional carbon fiber woven fabric is used to carry a load in the direction in which the FRP structure is required to be reinforced and a multiaxial stitch fabric is used to carry a load in other directions, these fiber base materials are used as carbon fibers for fabric formation. Since there is no crossing between the yarns and other reinforcing fiber yarns and the fibers are oriented straight without bending, and the fiber volume content increases, FRP
Excellent mechanical properties when used. In addition, since the carbon fibers or other reinforcing fibers are not tightened by interlacing of the yarns, the resin can be sufficiently impregnated even in the vacuum bag molding of the present invention, and the impregnation speed can be increased. .

The resin used in the molding of the present invention is a room temperature-curable, thermosetting resin such as an epoxy resin, an unsaturated polyester resin, a vinyl ester resin or a phenol resin which is liquid at room temperature. The viscosity of the resin used is preferably a low-viscosity resin from the viewpoint of the impregnation property and the impregnation rate of the resin.
It is about 10 to 10 poise, more preferably 0.5 to less than 5 poise. Among them, the vinyl ester resin is capable of reducing the viscosity of the resin and has a resin elongation of 3.5 to 12
%, It is preferably used because it not only has excellent moldability but also has high strength and excellent impact resistance.

The peel ply used in the molding of the present invention is a sheet that is peeled off from the FRP after the resin is cured, but it is necessary that the resin can pass through the ply, and it is necessary to be able to pass the resin. Fiber fabrics and the like. In addition, nylon fiber woven fabrics and polyester fiber woven fabrics are preferably used because they are inexpensive, but in order to prevent oils and sizing agents used in manufacturing these woven fabrics from being mixed into the FRP resin,
In order to perform scouring and to prevent shrinkage of the room-temperature-curable resin due to heat generated by curing, it is preferable to use a heat-set fabric.

The edge breather used in the molding of the present invention needs to be able to pass air and resin, and is made of nylon fiber fabric, polyester fiber fabric,
A mat made of glass fiber fabric, nylon fiber, or polyester fiber can be used.

The bag film used in the molding of the present invention is required to be airtight, and may be a nylon film, a polyester film, a PVC film, or the like.

[0068]

【Example】

(Example 1) A carbon fiber yarn of a multifilament having a filament count of 70,000 and a fineness of 52,000 denier is used as a warp yarn, an auxiliary yarn made of 608 denier glass fiber is used as a weft yarn, and a warp yarn density is 0. A carbon fiber woven fabric A having a flat structure of 87 fibers / cm and a weft yarn density of 2 fibers / cm, in which carbon fibers are arranged in one direction and having a basis weight of 503 g / m ² , was produced. In addition, in the eye-stopping treatment, the insertion of the weft of the glass fiber yarn is performed with a low melting point of 50 mm.
The method was performed in such a manner that the nylon fiber was aligned with the denier copolymerized nylon yarn, and after inserting the weft yarn, the copolymerized nylon yarn was melted by a far-infrared heater mounted on a loom, and the carbon fiber yarn and the glass fiber yarn were bonded. Since a tow-like yarn was used as a warp yarn, a gap between carbon fiber yarns of the obtained woven fabric could be secured, and the length was 1.2 mm.

Next, using the above-mentioned carbon fiber fabric, molding was carried out by the following method of the present invention.

Two carbon fiber woven fabrics A of the present invention having a width of 100 cm and a length of 100 cm, glass fibers of a width of 100 cm and a length of 100 cm, and a fiber weight of 450 g
/ M ² chopped strand mats were prepared.

First, a carbon fiber woven fabric A of the present invention (hereinafter, this carbon fiber woven fabric A is referred to as carbon fiber woven fabric A ₁ ) as a reinforcing fiber base is placed on a mold on which a release agent is applied. Then, three chopped strand mats are laminated one by one so that the end of the mat and the end of the fabric are aligned, and the carbon fiber fabric of the present invention (hereinafter, this carbon fiber fabric) is further laminated thereon. the a is referred to as the carbon fiber fabric a _2.) of 1
A total of five fiber substrates were laminated.

A nylon filament woven fabric as a peel ply is placed on a fiber base material, and a polyethylene medium having a thickness of 1.0 mm, a mesh opening size of 2.6 × 2.6 mm, and a mesh opening ratio are placed thereon. (Total area; ratio of mesh opening area to 100) is 6
Two sheets of 2% mesh were placed so as to cover the entire surface of the fiber base material.

A glass fiber woven fabric as an edge breather was stretched around the laminated fiber base material so as to have substantially the same thickness as the base material laminate, and a suction port of a vacuum pump was attached.

The whole was covered with a bag film made of a nylon film, and the bag film was bonded with a molding die and a mounting port of a suction port with a sealing material so that a vacuum state could be maintained.

A resin discharge port was provided at the center of the bag film, and the film and the discharge port were similarly bonded with a sealant so that a vacuum state could be maintained.

Next, after the inside covered with the bag film was evacuated to 755 Torr by a vacuum pump, the valve was opened and a room temperature-curable vinyl ester resin having a resin viscosity of 3 poise was injected. The resin immediately diffused into the resin diffusion medium over the entire surface of the laminated base material. Then the carbon fiber woven fabric A _1, also passes through the gap between the carbon fiber thread of carbon fiber fabric A _1, is resin in the thickness direction of the laminated base material into chopped strand mat layer resin flows between the fibers The time required for the impregnation and the resin impregnation of the laminated base material was 16 minutes. After the resin was cured, the molded plate was cut and the cross section was observed.
The resin was completely impregnated because the resin was impregnated in a vacuum state.

Comparative Example 1 For comparison, a multifilament carbon fiber yarn having a filament count of 12,000 and a fineness of 7,200 denier was used as a warp yarn, and an auxiliary yarn made of 608 denier glass fiber was used as a weft yarn. The warp yarn density is 6.20 yarns / cm and the weft yarn density is 2 yarns / cm.
A carbon fiber fabric B having a flat structure in which carbon fibers were arranged in one direction and having a carbon fiber weight of 496 g / m ² was produced. There is almost no gap between the carbon fiber yarns of the obtained woven fabric, and 0 mm
Met.

[0078] changing only the carbon fiber woven fabric A in the fabric B, others were the same as in Example (Thus, the fabric B ₁ represents the fabric A _1, the fabric B ₂ is the fabric A _2, corresponding respectively)
Molding was performed. Although the resin was immediately diffused into the entire surface of the laminated base material in the resin diffusion medium, the fabric B ₂ at the top of the laminated base material
Carbon fiber basis weight is large fabric, and the gap between the carbon fiber thread also does not flow easily the resin to hardly because chopped strand mat layer, sufficiently without resin flows to the fabric B ₁ laminated on the lower resin injection After 50 minutes from the start, gelling of the resin started, and molding failed.

[0079]

As described above, the carbon fiber woven fabric of the present invention is composed of a tow-like thick carbon fiber yarn, and despite the large fiber weight per sheet, the carbon fiber yarn of this woven fabric is large. According to the molding method of the present invention, there is a gap between the resin and the resin spreads over the entire surface of the fiber base laminate in which the resin easily flows, and the resin impregnation proceeds in the thickness direction of the fiber base laminate. Therefore, not only the labor of lamination is reduced, but also the impregnation of the resin is completely performed, and the time for injecting the resin is reduced, so that the workability is improved.

The fiber-reinforced plastic of the present invention is made of a tow-like thick carbon fiber thread, but can be easily impregnated with a resin, so that FRP can be obtained at low cost and excellent in mechanical properties.

According to the FRP molding method of the present invention, a bulky carbon fiber fabric is used, and in vacuum bag molding, the resin is diffused over the entire surface via a medium. To spread the resin over the entire surface,
Since the resin impregnation property is good and the resin impregnation time can be reduced, an FRP molded product can be manufactured at low cost.

[Brief description of the drawings]

FIG. 1 shows a unidirectional carbon fiber fabric according to an embodiment of the present invention.

FIG. 2 shows an exemplary embodiment of the unidirectional reinforced fabric of the present invention having warp assist yarns.

FIG. 3 is a cross-sectional view of one embodiment for explaining a method of forming an FRP of the present invention.

FIG. 4 is a perspective view of a resin diffusion medium.

FIG. 5 is a perspective view of an apparatus for measuring a hook drop value.

FIG. 6 is an enlarged partial front view of the hook drop value measuring device.

FIG. 7 is a partial perspective view of a device for measuring a hook drop value.

FIG. 8 is a cross-sectional view of another embodiment illustrating a method of forming an FRP of the present invention.

FIG. 9 is a schematic perspective view illustrating a molding material.

[Explanation of symbols]

 1: Cross section of carbon fiber yarn 2: Carbon fiber yarn 3: Auxiliary yarn 4: Warp direction auxiliary yarn 5: Membrane 6: Mold 7: Carbon fiber fabric 8: Peel ply 9: Medium 10: Suction port 11 : Edge breather 12: Bag film 13: Seal material 14: Discharge port 15: Valve 16: Bar of group A 17: Bar of group B 18: Molding material 19: Block obtained by winding a carbon fiber fabric around molding material 20: Groove 101: Carbon fiber thread 102: Metal hook 103: Weight 104: Upper clamp 105: Lower clamp 106: Cotton thread

Claims (13)

[Claims] 1. A tow-like carbon fiber yarn having a filament number of 40,000 to 400,000.
0, wherein the carbon fiber yarns are arranged in the warp direction, and the auxiliary yarns are arranged in the weft direction, and there is a gap between the carbon fiber yarns. Textile fabric. 2. A carbon fiber yarn having a tow-like carbon fiber yarn fineness of 25,000 to 350,000 denier, wherein the carbon fiber yarns are arranged in the warp direction, and the auxiliary yarns are A unidirectional carbon fiber woven fabric which is arranged in a horizontal direction and has a gap between the carbon fiber yarns. 3. A tow-like carbon fiber yarn, wherein the carbon fiber yarns are arranged in a warp direction, and auxiliary yarns are arranged in a weft direction, and a gap is formed between the carbon fiber yarns. A unidirectional carbon fiber woven fabric, wherein the basis weight of the carbon fiber is 450 to 1,500 g / m ² . 4. The filament number of the carbon fiber yarn is 4
0000 to 100,000 yarns, yarn fineness of 30,00
0-70,000 denier and carbon fiber basis weight of 4
2. The amount is from 100 to 700 g / m < ² >.
4. The unidirectional carbon fiber fabric according to any one of 3. to 3. 5. A weft direction auxiliary yarn group that intersects with the carbon fiber yarn group on both sides of the yarn group, wherein the carbon fiber yarn forms a yarn group without substantially bending. The weft direction auxiliary yarn group and the warp direction auxiliary yarn group parallel to the carbon fiber yarn group form a woven structure and integrally hold the carbon fiber yarn group. Is the unidirectional carbon fiber woven fabric according to any one of 4. 6. The gap between the carbon fiber yarns is 0.2 to 2 m.
The unidirectional carbon fiber fabric according to any one of claims 1 to 5, wherein m is m. 7. The carbon fiber yarn and / or the warp direction auxiliary yarn and the weft direction auxiliary yarn are adhered to each other at the intersection thereof. Carbon fiber fabric. 8. A fiber reinforced plastic obtained by reinforcing a laminated fiber base material with a resin, wherein at least one layer of the fiber base material is the carbon fiber fabric according to claim 1. A fiber-reinforced plastic characterized by the following. 9. A matrix comprising a fiber-reinforced plastic containing the carbon fiber fabric according to claim 1 and a molding material other than the fiber-reinforced plastic, wherein the fiber-reinforced plastic and the molding material constitute a fiber-reinforced plastic. A fiber-reinforced plastic structure, wherein the matrix resin is filled in a groove formed in a molding material on the fiber-reinforced plastic side, which is integrated with a resin. 10. A carbon fiber woven fabric according to any one of claims 1 to 7, wherein at least one or more layers are laminated as a fiber base material, and a medium for diffusing the resin in the surface direction is placed thereon. After that, the whole is covered with the bag film, and then the inside covered with the bag film is evacuated, the room temperature-curable resin is diffused on the surface of the laminated fiber base material, and the fiber base material is impregnated with the resin. A method of molding a fiber-reinforced plastic. 11. A carbon fiber woven fabric according to any one of claims 1 to 7 as a fiber base material, and at least one layer of the fiber base material laminated on a mold in which a medium for diffusing in the plane direction is placed. Then, after further placing a medium thereon, the whole is covered with a bag film, and then the inside covered with the bag film is evacuated, and the room temperature curable resin is diffused on the surface of the laminated fiber base material, A method for molding a fiber-reinforced plastic, comprising impregnating a fiber base material with the resin. 12. The carbon fiber woven fabric according to claim 1, which is used as a fiber base material, and is formed on a molding material having a groove serving as a resin flow path on the surface thereof so that the fiber is in contact with the groove. Laminate at least one layer of the base material, further cover the whole with a back film, then make the inside covered with the back film a vacuum state, diffuse resin from the groove of the molding material in contact with the fiber base material, A method for producing a fiber-reinforced plastic, comprising: integrating a fiber base material and a molding material while impregnating a laminated fiber base material with a room-temperature-curable thermosetting resin. 13. The method for producing a fiber-reinforced plastic according to claim 9, wherein the molding material is a foam.