JPH07223271A - Bent pipe and method and apparatus for producing the same - Google Patents

Abstract

PURPOSE:To produce an FRP bent pipe or racket having excellent characteristics and stable quality without producing a void, a pinhole and a resin flow defective part on the surface thereof. CONSTITUTION:A fiber reinforced plastic bent pipe or racket to be produced has an inner reinforcing fiber layer 4 and an outer nonwoven fabric layer 5 composed of a reinforcing layer with a monofilament diameter of 20mum or less and a basis wt. of 100-g/m<2> or less.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a bent pipe made of fiber reinforced plastic (hereinafter also referred to as FRP), a manufacturing method and an apparatus therefor, and particularly an optimum structure and manufacturing method applied to a FRP racket. And equipment.

[0002]

Conventional FRP bent pipes, for example FR
There are various problems as described below in the P racket and the frame of the bicycle and the manufacturing process thereof. A conventional racket frame forming method is, for example, a woven fabric of carbon fibers or glass fibers which are reinforcing fibers, a sheet aligned in one direction, or a laminated sheet obtained by stacking the unidirectional sheets obliquely or crossing each other. After making a prepreg sheet impregnated with an epoxy resin or an unsaturated polyester resin, and cutting the prepreg sheet into a predetermined width,
As described in JP-A-5-96030,
The cut narrow prepreg sheets are laminated one by one around a core material covered with a resin or rubber tube (film). In this way, the preforms, which are wound and laminated one by one, are mounted in the mold,
While heating the mold, a pressure medium (for example, compressed air) is injected into the tube from which the core material has been extracted to perform pressure molding (generally called "internal pressure molding method").

In such an internal pressure molding method, the preform is set to have an outer diameter smaller than the outer diameter of the cavity of the die so that the preform can be easily attached to the die. Therefore, the preform is expanded to the outer diameter of the cavity by the pressure of the pressurizing medium in the tube during the thermoforming.

However, in the conventional method as described above, FIG.
0, as shown in FIG. 61, a tube 20 made of resin or rubber.
Prepreg 203 is provided on the outer periphery of the core material 202 coated with 1.
Since each of the layers is wound and laminated, an overlapping portion (overlap portion) occurs in each layer. Eventually, all layers must move to expand in the circumferential direction at the time of heating and pressure molding in the mold, but there are many overlapping parts, so movement for expansion cannot be achieved completely. Occurs, and the outer layer does not reach the mold, or even if it reaches the mold, it cannot receive the original pressure, and molding defects such as voids and resin flow defects occur on the outer surface of the racket frame molded product. Often. Therefore, there is a problem that the surface quality and strength of the molded product vary greatly.

Further, in manufacturing the preform, since the prepreg 203 is wound around the core material 202 one layer at a time,
There was also a problem that work efficiency was very poor.

Further, according to the method as described above, molding as shown in, for example, FIG. 62 is performed in the mold.
In the figure, 204 is a resin tube (for example, nylon) from which the core material 202 is removed, 205 is a fiber reinforced layer (prepreg) composed of reinforcing fibers and matrix resin, and 2
Reference numerals 06 and 207 are molds, 208 is a mold mating surface, and 209 is a core that forms a gut tension surface of the racket frame and that is retracted so that it can be removed from the mold when the mold is removed.

Since the racket frame is composed of a large number of fine curved surfaces and is molded in a closed mold unlike a flat plate, it is located farthest from the mold mating surface 208 and has a small curvature. The voids and the pinholes 210 are likely to be formed as shown in (3), and the fact that they have to be putty-filled has been a cause of lowering the productivity.

Moreover, in the conventional method of applying internal pressure to a prepreg consisting of reinforcing fibers and a matrix resin and curing by heating, the reinforcing fibers constituting the prepreg adhere to the inner wall of the mold when the internal pressure is applied. This has been a cause of reducing the fluidity of the matrix resin and impairing the deaeration property. When the fluidity of the resin is lowered and the degassing property is impaired, the voids and pinholes 210 described above are likely to occur, and the surface quality is deteriorated.

Further, in the conventional internal pressure molding method, there is a reason as described below, and therefore, the pressure is relatively low (for example, 12 kg in compressed air).
/ Cm ² or less). Therefore, poor adhesion of the resin-impregnated reinforced fiber layer to the wall forming the cavity occurs, the air in the mold cannot be completely exhausted, and voids occur, or the amount of resin is insufficient at a certain site. There is also the problem of running out of volume.

Further, as to the preform of the bent pipe such as the racket frame, the forming method is as described above, in which the prepreg sheets in which the orientation directions of the reinforcing fibers are different are covered with the resin or rubber tube in the predetermined stacking order. A method in which the core material is manually wound one layer at a time, or prepreg sheets are arranged in a stacking order on a table and the core material covered with a resin or rubber tube is rotated while being pressurized and heated to form a seaweed roll. A method of winding the wire around the wire is generally known.

However, in such a preform molding method, the work efficiency is poor, the work takes time, the quality is not stable, and automation is difficult. If such a process is present in the racket manufacturing process, the quality of the molded racket is not stable, and the manufacturing cost rises.

In the internal pressure molding method, a relatively low pressure is usually applied as described above, but a pressure is applied from the inside of a molding base material provided with a resin-impregnated fiber reinforced sheet around a tubular film. When the medium pressure is small, its surface,
In particular, in a portion where the cross-sectional shape of the frame changes in the axial direction such as a racket frame, irregularities and residual bubbles due to insufficient adhesion of the FRP molding base material to the inner wall surface of the mold are usually present on the surface of the molded product. However, the problem that the appearance quality deteriorates tends to occur. Here, the pressurizing medium refers to a pressure transmitting medium filled in the inside of the fiber reinforced sheet in order to press the fiber reinforced sheet into a mold until the resin is thermoset. , For example, JP-A-56
In Japanese Patent No. 166862, 6 kg / cm ² · G
The above-mentioned nitrogen gas is disclosed in JP-A-53-9643 as an example of compressed air having a pressure of about 30 bar (30.6 kg / cm ² · G). Gas is usually used.

However, in the method of utilizing gas as the pressurizing medium, the method of connecting the tubular film and the external pressurizing device is easy, and even if the gas leaks due to poor connection, the molded product is contaminated. Although it has the advantage of having little adverse effect, since gas is a compressive fluid, handling above 30 kg / cm ² poses a serious drawback due to high-pressure molding, in addition to the risk of handling and increased production equipment costs. Therefore, it is not possible to meet the demand to suppress the generation of surface defects by increasing the pressure of the pressurized medium.Therefore, when a low pressure medium is used as a countermeasure, this time, surface defects due to low pressure inevitably occur. , The cost for correcting this surface defect in the post processing has led to cost increase.

Therefore, it is conceivable to use a non-compressible fluid such as water or oil as opposed to the method of using a compressible fluid, but it is difficult to contain a liquid having no fixed shape without leaking, The invention disclosing such specific means is not found. Further, even if a means of using an incompressible fluid as the pressurizing medium can be realized, if the liquid leaks, there is a problem that productivity is affected. From the above, the Japanese Patent Laid-Open Publication No. 56-56
Japanese Patent No. 166862 also does not disclose a specific method for connecting a rubber tube, which is a tube for introducing a pressurizing medium to a tubular film, and an external pressurizing device. Normally, the joint connecting the external pressurizing device and the flexible tube employs so-called caulking for the joint portion for pressure resistance and leakage prevention. Filling a high pressure, incompressible fluid into a flexible tube,
Moreover, since the molding temperature is usually 120 ° C. to 150 ° C., it is necessary to caulk the heat-resistant rubber elastic body. However, in such a case, the expansion of the rubber when the temperature rises causes a decrease in the caulking force, which causes leakage of the incompressible fluid. Breakage becomes a problem.

Further, in the internal pressure molding method, good adhesion of the fiber reinforced sheet layer to the mold is required. Therefore, it is preferable that the reinforced fiber layer has a property of easily conforming to the mold (good fit property). . As a technology that meets these needs,
There is known a technique in which a reinforcing fiber layer is composed of multiple braids, and a resin is impregnated into the reinforcing fiber layers to perform internal pressure molding. Japanese Patent Publication No. 5-80329 is known as a method for producing the prepreg of the multiple braid.

In the prior art relating to a multi-braided prepreg, since a solvent-free resin is used, there is a problem that it is generally highly viscous and difficult to be completely impregnated, and in particular, it becomes difficult to impregnate as it becomes a multi-layer. In addition, it is necessary to select a low-viscosity resin to facilitate resin impregnation, and there is little freedom in resin selection, and when a resin with a relatively high viscosity is used, it is completely impregnated and the production rate decreases. Need to deal with. Moreover, since the braided material has a braided structure, the surface is generally non-smooth as compared with the unidirectionally oriented prepreg,
There is also a problem that defects such as voids and pinholes are likely to occur on the surface of the molded product. Further, in order to wind the braided prepreg, it is necessary to separate the release paper. Furthermore, the braid is assembled in a stretched state according to the tension when braiding, but since the structure is loose, it has elasticity and when the tension is released the stretch recovers and becomes thicker, and the braid width and length are not stable. There is also.

In the above Japanese Patent Publication No. 5-80329,
In order to solve the problem of stretchability of the braid, it is said that it will be done with a triaxial structure braid, but although the triaxial structure braid can solve the stretchability in the axial direction, it also reduces the stretchability in the width direction. However, the fitting property to the molding shape, which is one of the characteristics of the braid, is greatly impaired.

A method of manufacturing FRP bent tubes, such as tennis racket frames, is described in US Pat. No. 3,753.
So-called Resin Transfefer M as described in the specification of JP-A No. 5,037 and JP-A No. 3-176083.
A method called olding is known. US Patent No. 3,
The method of No. 755,037 covers a mandrel formed by bundling a steel wire with a flexible tube, forms a helical wound layer of reinforcing fibers around the tube, and then pulls out the mandrel to form a preform, Put the preform in a lower mold having a cavity having a desired racket frame shape, and apply resin to the helical winding layer,
After the upper mold is closed, the helical winding layer is impregnated with resin while molding while pressurizing the inside of the tube.

However, in this method, the resin is applied to the helical winding layer of the preform placed in the lower mold, the upper mold is closed, and then the resin is impregnated into the helical winding layer and molding is performed, so that the resin is confined. However, there is a problem in that air cannot escape completely and crater-like holes and pinholes are easily formed on the surface of the obtained racket frame.

Further, in the method disclosed in Japanese Patent Laid-Open No. 3-176083, a cloth, a sleeve, and a roving made of a fiber-reinforced base material having a flexible tube as a core are placed in a mold, and then a polymerization catalyst and an initiator are included. Molten ω-lactams are poured into a mold and heated while applying pressure to the core to form a hollow racket frame with a polyamide resin matrix.

However, in this method, since the polymerization reaction in the mold involves a rapid reaction, it is difficult to set the amount of the initiator and the temperature, and it is difficult to control the degree of polymerization and the reaction time.
Therefore, there is a problem that voids are easily generated. However, if holes or pinholes are formed on the surface of the frame, the surface quality will be impaired, and if there is a difference in the resin content, the physical properties will deteriorate and the weight balance will be impaired, reducing the commercial value.

[0022]

SUMMARY OF THE INVENTION In view of various problems as described above, an object of the present invention is to provide a manufacturing method and apparatus in which voids, pinholes, and resin flow defective portions do not occur on the surface of a molded article, and molding by the method. It is intended to provide a bent pipe and a racket made of FRP, which has a stable quality with excellent properties.

Another object of the present invention is to provide a preform for producing a molded product of excellent quality as described above, a method for producing the same, and an apparatus for producing the preform.

[0024]

In order to achieve the above object, the FRP bent tube of the present invention has a reinforcing fiber layer on the inner side, and a single yarn diameter of 20 μm or less on the outer side of the reinforcing fiber layer. And a non-woven fabric layer having a basis weight of 100 g / m ² or less.

The FRP racket according to the present invention is
A racket made of fiber reinforced plastic, in which a reinforcing fiber layer is arranged on the inside, and a single yarn diameter is 20 on the outside of the reinforcing fiber layer.
and a non-woven fabric layer having a basis weight of 100 g / m ² or less and having a weight of 100 μm or less.

In such a bent pipe or racket made of FRP, the nonwoven fabric layer is
It functions as an outflow path to make the matrix resin that has received internal pressure reach the die mating surface easily, and when such resin is discharged from the die mating surface, it is inside and on the surface layer of the preformed molding substrate. Since air bubbles are included, deaeration is improved, and a formed body having a good surface quality with very few voids and pinholes can be obtained. Further, since the amount of resin discharged is increased as compared with the conventional racket frame, the weight of the molded body can be reduced, and the fiber volume content of the entire outer shell layer can be increased to increase the strength. Therefore, it is possible to obtain a bent pipe or a racket having a good appearance and surface quality and excellent strength characteristics.

Here, the single yarn diameter of the fibers of the non-woven fabric layer is 20 μm.
If it exceeds m, the density of the non-woven fabric layer becomes large, so that the surface smoothness of the molded product is impaired, and further the resin flows out. Further, if the fiber areal weight exceeds 100 g / m ² , the resin also leads to excessive outflow, which may cause voids, pinholes, or the like, and lead to a decrease in strength. Further, if the basis weight is too large, the weight of the molded product is increased, and therefore the low basis weight as described above is preferable also from this aspect.

Carbon fibers, glass fibers, various organic fibers (for example, polyaramid fibers) can be used as the reinforcing fibers of the reinforcing fiber layer, and carbon fibers, glass fibers, polyaramid fibers, etc. can also be used as the fibers of the nonwoven fabric layer. Can be used. As the fibers of the non-woven fabric layer, carbon fibers are most preferable because they have a small fiber diameter and do not fluff during polishing after molding.

In the FRP bent pipe and racket of the present invention, various forms can be used as the form of the reinforcing fiber layer. For example, a reinforced fiber layer includes a unidirectionally aligned body of reinforced fibers in which reinforced fibers are aligned in one direction, or a reinforced fiber layer in which the arranging directions of the reinforced fibers intersect in at least two directions. It is possible to use those in which the reinforcing fiber layer includes a reinforcing fiber woven layer or a braided layer. In addition, any combination of these may be included.

In the reinforcing fiber layer having such a form,
As will be described in detail in the section of the preform described later, it has a reinforcing fiber layer in a range not exceeding 4 sets, each reinforcing fiber layer has a laminated constitution of a plurality of reinforcing fiber materials, and has a cross section of It is preferable that the reinforcing fiber layer is C-shaped and that the opening of the lower reinforcing fiber layer is covered with the upper reinforcing fiber layer. By taking such a shape, the preform molding is greatly facilitated. It

Further, as described above, as the reinforcing fiber layer,
The structure may include a braid of reinforcing fibers. Preferably, the braid of reinforcing fibers is constructed in multiple braids. By using a braid, a good fitting property to the original molding shape of the braid is ensured, and at the same time, the presence of the non-woven fabric layer ensures good fluidity and deaeration of the resin, and a molded product with a good surface quality. Is obtained.

The fibers forming the non-woven fabric of the non-woven fabric layer are preferably short fibers having a fiber length of 1 to 30 mm, more preferably 5 to 20 mm. If the fiber length exceeds 30 mm, the fluidity of the resin will be hindered and conversely 1
If it is shorter than mm, it may flow out together with the resin.

When the epoxy resin is used as the matrix resin of the molded product, the adhesive used for processing the nonwoven fabric itself is preferably one having the lowest water absorption. More preferably, the same type as the matrix resin is desirable. In addition, it is preferable that such a fixing agent dissolves or softens at the molding temperature from the viewpoint of the widening property of the reinforcing fiber layer and the nonwoven fabric layer.

Further, this non-woven fabric is further laminated on the outermost layer of the frame forming base material in the manufacturing stage, but it spreads if left for a while due to the rigidity of the fibers used in the non-woven fabric,
It may cause biting when setting the mold.
Therefore, the workability is improved by impregnating the non-woven fabric with a resin so that the non-woven fabric has tackiness. That is, it is preferable that the non-woven fabric layer is also made into a prepreg.

Examples of the matrix resin for the bent pipe and the racket according to the present invention include thermosetting resins such as epoxy resin, unsaturated polyester resin, vinyl ester resin and phenol resin. When the non-woven fabric layer is prepreg-prepared for production as described above, it is preferable that the impregnating resin is of the same type as these matrix resins from the viewpoint of preventing reduction in interlaminar peel strength.

When the nonwoven fabric is impregnated with resin,
It is not necessary to increase the amount too much, and the workability was good when the ratio of the nonwoven fabric to the impregnated resin was 3: 7 (weight ratio), for example.
Even if the amount is more than this, most of the resin impregnated into the nonwoven fabric will flow out during molding, which is wasteful.

The fibers of the nonwoven fabric layer are preferably oriented substantially in one direction. It is also possible to set the molding base material in a mold and align the orientation direction of the fibers with the escape direction of the resin or air when performing internal pressure molding.
The orientation direction of the fibers can be naturally achieved in the non-woven fabric manufacturing stage without any special intention. That is, in the manufacture of a nonwoven fabric, usually, short fibers are dispersed on a belt that circulates around, but since the belt has a speed in a certain direction, the short fibers deposited on the belt are also arranged to some extent in the belt running direction. This is because the non-woven fabric is substantially directional.

The structure of the bent pipe or racket frame having the above-mentioned non-woven fabric layer is as shown in FIG. 1, for example. FIG. 1 shows a layer structure of a racket frame according to the present invention, in which a resin (for example, nylon) is used as the innermost layer.
Or rubber inner pressure molding tube 1 (cylindrical film),
A fiber reinforced layer 4 composed of reinforcing fibers 2 and a matrix resin 3 is provided on the outer side thereof, and a nonwoven fabric layer 5 impregnated with a matrix resin is provided at the outermost layer.

The thickness of the non-woven fabric layer is not particularly limited, but the thickness of 0.05 to 0.2 mm ensures the fluidity of the resin described above, prevents the occurrence of voids, and further reduces the weight of the molded product. It is preferable from the viewpoint. The volume content of fibers in the non-woven fabric layer is preferably 5 to 30%.
If the fiber volume content is too high for the same reason that the basis weight is 100 g / m ² or less, the fluidity of the resin is impaired and the weight of the molded product is increased. On the contrary, if it is too low, the effect of the presence of the non-woven fabric layer is impaired.

The non-woven fabric layer may be arranged over the entire length of the curved pipe or racket in the lengthwise direction, or may be partially provided in the lengthwise direction. For example, the non-woven fabric layer may be provided over the entire length of the racket other than the grip, or may be provided near the yoke of the frame.
In particular, the area around the joint between the frame and the yoke is a region where voids and pinholes are likely to occur during molding, so that the effect is great.

The non-woven fabric layer may be arranged over the entire circumference in the circumferential direction of the curved pipe or the racket frame,
It may be partially arranged, for example, in a portion other than the gut groove portion in the circumferential direction of the racket frame.

Further, the non-woven fabric layer may be formed by laminating a plurality of layers. Further, it is preferable that the non-woven fabric layer is provided by winding a non-woven fabric sheet having a predetermined width in the circumferential direction of the curved pipe or the racket frame, not by so-called spiral winding. As a result, the process can be simplified and the overlapping portion of the non-woven sheet can be reduced to improve the surface smoothness.

Further, it is possible to dispose a core material at least partially made of a honeycomb body or wood inside the frame of the racket and / or the reinforcing fiber layer of the yoke. By arranging such a core material, it is possible to further reinforce a necessary part partially and improve the strength characteristics.

Further, the bent pipe according to the present invention can also be constructed to have a specific reinforcing fiber layer which does not have the non-woven fabric layer as described above. That is, the bent pipe according to the present invention has a reinforcing fiber layer in a range not exceeding 4 sets, each reinforcing fiber layer has a laminated structure of a plurality of reinforcing fiber materials, and has a C-shaped cross section. In addition, the upper reinforcing fiber layer covers the opening of the lower reinforcing fiber layer. In such a bent pipe,
The reinforcing fiber material is, for example, a unidirectionally aligned body of a reinforcing fiber or a woven fabric.

The FRP bent pipe and racket as described above are preferably manufactured using the following preforms. That is, the FRP bent pipe or racket forming preform according to the present invention has a reinforcing fiber layer in a range not exceeding 4 sets, and each reinforcing fiber layer has a laminated constitution of a plurality of reinforcing fiber materials. In addition, the cross section is C-shaped, and the opening of the lower reinforcing fiber layer is covered by the upper reinforcing fiber layer. This reinforcing fiber layer is preferably prepregized.

That is, in a conventional preform, for example, as shown in FIG. 64, a reinforcing fiber sheet or a prepreg 213 is sequentially wound around a core material 212 coated with a nylon tube 211, and the core material 212 is wound one by one. The reform 214 was produced. Therefore, the workability is poor, it is troublesome, and the quality is not stable.

The preform according to the present invention has the structure as described above, and is structured as shown in FIGS. 2 and 3, for example. In the figure, 11 and 12 are tubular films 14
A range not exceeding four sets (two in the illustrated example) wound on the core material 13 covered with (for example, a nylon tube) so as to have overlapping regions at both sides in the width direction.
2) shows a reinforcing fiber layer or prepreg sheet having a laminated structure of a plurality of reinforcing fiber materials or prepregs and having a C-shaped cross section. And
The upper reinforcing fiber layer or prepreg sheet covers the opening of the lower reinforcing fiber layer or prepreg sheet.
The preform 15 is subjected to internal pressure molding in a state where the core material 13 is extracted.

The preform 15 as shown in FIG.
When the racket frame is used for molding, it is preferable that the gut hole 16 and the gut tension groove 17 are provided in the overlapping portion as shown in FIG. 4, for example.

In addition to the embodiment shown in FIG. 3, for example, as shown in FIG. 5, a core material 2 covered with a tubular film 21 is provided.
It is also possible to use a preform 25 in which the overlapping area of the reinforcing fiber sheet or prepreg sheets 23, 24 wound on the second sheet 2 is further increased.

In the embodiment shown in FIGS. 3 and 5, two reinforcing fiber sheets or prepreg sheets are wound, but if necessary, a sheet may be further wound on the reinforcing fiber sheets or prepreg sheets. . However, if the number of wound layers becomes too large,
Since the difference from the conventional one-by-one winding is small,
In that case, the number of laminated reinforcing fiber layers or prepreg layers forming the wound sheet may be increased so that the total number does not exceed 4 sets.

Such a preform is formed, for example, by the following method. That is, the method for producing a preform according to the present invention, on the tubular film covered with the core material, at least, the first reinforcing fiber sheet having a width shorter than the entire circumference of the tubular film is wound, A second reinforcing fiber sheet is wound on the first reinforcing fiber sheet so as to cover the opening of the wound first reinforcing fiber sheet. Here, each of the first reinforcing fiber sheet and the second reinforcing fiber sheet is usually formed by laminating a plurality of reinforcing fiber materials.

Further, it is preferable that the first reinforcing fiber sheet and the second reinforcing fiber sheet are prepregized.

For example, as shown in FIG. 6, a predetermined number of reinforcing fiber sheets or prepreg sheets 26 are laminated, and a reinforcing fiber sheet or prepreg sheet 27 formed by the lamination is formed with a predetermined width as shown in FIG. Then, the first reinforcing fiber sheet or the first prepreg sheet and the second reinforcing fiber sheet or the second prepreg sheet are cut.

Then, as shown in FIG. 8, for example, a first reinforcing fiber sheet or prepreg sheet 30 is first wound on a core material 29 covered with a nylon tube 28 to cover an opening 31 and an opening 31. First on both sides of
By winding the second reinforcing fiber sheet or prepreg sheet 32 so as to overlap with the reinforcing fiber sheet or prepreg sheet 30 of No. 1, a preform as shown in FIG. 5 is formed.

In the so-called two-part preform as described above, the total number of layers moved during molding is 2 as compared with the conventional case where the layers are laminated one by one.
Since there are only the locations, the molding is easy, that is, both the reinforcing fiber sheets or the prepreg sheets easily expand and move when the internal pressure is applied, and the defective movement is extremely small, and the defective molding hardly occurs. Further, the number of windings on the core material is only required to be two times for the outer laminated body, so that the working time is short and the efficiency is high. Further, since the number of times of winding is small and the prepregs to be wound are already laminated in multiple layers, the rigidity is high and the mechanization of the winding work, that is, the automation is facilitated. In the above example, an example of a two-divided structure composed of two sets of reinforcing fiber sheets or prepreg sheets has been described. There is enough.

A non-woven fabric layer is preferably provided on the outer side of the preform formed as described above, as described above. The non-woven fabric layer has a single yarn diameter of 20.
It is preferably μm or less and the basis weight is 100 g / m ² or less. A preform provided with such a non-woven fabric layer has a structure as shown in FIG. 9, for example.

The so-called two-part preform as described above can be formed using the following apparatus. That is, the manufacturing apparatus of the tubular preform according to the present invention holds the core material covered with the tubular film and the prepreg sheet of the reinforcing fiber provided on the core material, and the prepreg sheet along the outer shape of the core material. Press on the upper and lower surfaces of the core material,
A pair of upper and lower first pressing means movable in the vertical direction,
Bending the prepreg sheet along the outer shape of the core material, pressing the folded prepreg sheet against the side surface of the core material,
It is characterized in that it has a pair of left and right second pressing means movable in the left-right direction. Here, the second pressing means is provided, for example, in upper and lower two stages.

For example, as shown in FIGS. 10 to 20, the preform having the form shown in FIG.
42, and press plates 43, 4 provided on the left and right in two upper and lower stages.
It is formed as follows using a device having 4, 45, and 46.

The nylon tube-coated core material 47 used has a rectangular cross section and should not be tapered. The width of the upper and lower press plates 41, 42 needs to be narrower than the lateral width of the core material 47.
The height of 46 needs to be larger than the thickness of the core material 47.

Further, each press plate sequentially moves to a predetermined position during the bending operation of the prepreg. In this embodiment, the press plate is moved by an electric motor, but other means such as a cylinder utilizing fluid pressure can be used. Further, since the surface of the prepreg sheet has tackiness, it is desirable that the surface of the press plate is subjected to a tack-resistant treatment such as Teflon coating so as not to adhere to the press plate. Further, in order to hold the prepreg sheet so as not to shift during the bending operation, it is also effective to embed suction pads in a plurality of positions on the pressing surfaces of the upper and lower press plates to suck the prepreg when necessary.

When the prepreg is bent, the prepreg firmly adheres to the core material 47 and has a tackiness.
After bending, it is necessary to have drapeability so that the prepreg sheet does not peel off and return to its original state.Therefore, a heating facility to keep the ambient temperature inside the equipment at the optimum temperature for bending the prepreg is required. It is provided (not shown). The heating device may be configured such that an electric heater is embedded in the press surfaces of the upper and lower press plates.

The molding process shown in FIGS. 10 to 20 is a process of arranging the laminated prepreg and the tube covering core material 47 in the prepreg bending portion by a human or mechanical means, and after the arrangement, the operator starts the device with a start button. By pressing, the apparatus automatically operates, the six press plates are sequentially moved, and the prepreg is bent and wound around the core material.

First, as shown in FIG. 10, the lower press plate 4
2 rises to a position above the center point. Next, the prepreg sheet 48 and the tube covering core material 47 are sequentially arranged on the lower press plate 42.

Next, as shown in FIG. 11, the upper press plate 4
1 descends and presses the prepreg 48 and the core material 47. Next, the lower right and lower left press plates 46 and 45 move forward toward the center point. At this time, as shown in FIG. 12, the upper and lower press plates 41 and 42 descend while sandwiching the prepreg 48 and the core material 47, and bend the prepreg 48. Then, as shown in FIG. 13, the lower right and lower left press plates 46 and 45 are
The core material 47 is sandwiched by advancing toward the center point, and the prepreg 48 is bent 90 degrees and pressed. Next, the upper press plate 41
Rises.

Next, as shown in FIG. 14, the upper right and upper left press plates 44 and 43 are advanced to the center point, and the prepreg 48 is moved.
Is bent into a substantially C shape, and the lower press plate 42 is raised and pressed to fix the C shape.

Next, as shown in FIG. 15, the upper right and upper left press plates 44 and 43 are retracted, and the next prepreg 49 is placed on the core material 47.

Next, as shown in FIG. 16, the upper press plate 4
1 descends to sandwich the prepreg 49 and the core material 47. Then, the lower right and lower left press plates 46 and 45 retract.

Next, as shown in FIG. 17, the upper and lower press plates 41 and 42 descend while sandwiching the core material 47 and the prepregs 48 and 49. After that, upper right and upper left press plates 44, 43
Moves forward toward the center point.

Next, as shown in FIG. 18, the upper and lower press plates 41 and 42 are raised while sandwiching the core material 47 and the prepregs 48 and 49, and the prepreg 49 is bent. Then, as shown in FIG. 19, the upper right and upper left press plates 44 and 43 are
The core material 47 is sandwiched by advancing toward the center point, and the prepreg 49 is bent 90 degrees and pressed. Next, the lower press plate 4
2 descends.

Further, as shown in FIG. 20, the lower right and lower left press plates 46 and 45 are advanced to the center point, and the prepreg 4
9 is bent into a substantially C shape, and the upper press plate 41 is lowered and pressed to fix the C shape. When the preform molded by retracting the press plate is taken out, a preform as shown in FIG. 5 is obtained.

Here, in the case of further winding the prepreg sheet, the next prepreg sheet may be arranged in the apparatus and the above steps may be repeated. Further, the above steps are merely examples, and the moving order, position, etc. of the press plates can be changed according to the preform to be molded.

When a preform is formed by using the above-mentioned apparatus, by sequentially arranging the laminated prepreg sheet and the tube-coated core material in the apparatus, the six press plates in the apparatus are sequentially moved, and the semi-automatic As a general rule, the laminated prepreg sheet can be wound around the tube-coated core material, and the number of windings can in principle be two. Therefore, a long preform with stable quality can be efficiently formed in a short time.

The preform according to the present invention may have a structure using a braid, in addition to the above-described two-divided structure preform.

That is, the FRP bent pipe or racket forming preform according to the present invention is characterized by having a braiding layer made of reinforcing fibers and a non-woven fabric layer arranged outside the braiding layer. It consists of things.

This braided layer is preferably prepregized. Further, the braid layer may be composed of multiple braids.

Here, the fibers constituting the non-woven fabric of the non-woven fabric layer have a single yarn diameter of 20 μm or less and a basis weight of 100 g /
It is preferably m ² or less.

A method of manufacturing the above braided preform will be described with reference to the manufacturing apparatus shown in FIG. 21, for example. Using the braiding machines 51, 52, and 53 in multiple stations (three stations in this example), a fiber bundle 55 of reinforcing fibers is multi-braided on an airtight expansion tube 54 (for example, a nylon tube), and the braid 56 is made of resin. It is dipped in the liquid 57 to impregnate the resin, and the heating and drying device 5
8. The solvent is dried through water-cooled turn rolls 59 and 60 and a heating / drying device 61, and after passing through a water-cooling turn roll 62, a nonwoven fabric 63 is attached thereto from above and below and pressed by a calender device 64, and then the multilayer Braided prepreg 65
Is a method of winding.

In the method and apparatus as described above, braids are braided at the same angle for each layer or at different angles for each layer within the range of 10 to 60 degrees of braid angle (0 ° in the axial direction), and the fiber volume content is 40 to 70. % (Resin volume content 30 to 60%) is preferable.

Further, as the airtight expansion tube 58, any commonly used polymer material such as nylon, polyester, polypropylene, silicone and rubber can be used. Further, as shown in the drawing, a fiber bundle or a tape-like cloth 66 (woven cloth or non-woven cloth) may be passed through the outside of the airtight expansion tube 54 at the same time, and multiple braiding may be performed thereon.

As the resin to be impregnated, epoxy, unsaturated polyester, vinyl ester, phenol and other commonly used thermosetting resins can be used. Further, as the reinforcing fiber, carbon fiber, glass fiber, polyaramid fiber,
Fibers that can be used for the reinforcing fibers of other conventional composite materials can be used, both homogenous fibers or hybrid configurations of different fibers are possible.

As the non-woven fabric, carbon fiber, glass fiber,
Non-woven fabrics or prepregs made of polyaramid fibers, other conventional fibers can be used.

In such a method, in order to facilitate resin impregnation, it is preferable to adjust the viscosity of the impregnating resin by diluting with a solvent. By adjusting the viscosity, complete impregnation can be easily performed even with multiple layers. Further, since it is a solvent system, there is no restriction on the resin composition, and solvent-soluble raw materials can be freely selected and used.

By disposing a non-woven fabric on the surface of the braid, surface defects such as voids and pinholes during FRP molding can be almost eliminated. In addition, by using a non-woven fabric itself that is not processed as the non-woven fabric to be pasted on the surface of the braid, or a prepreg in which resin is applied to only one side, separation by release paper is not required, and handleability during use is improved. .

Further, in order to solve the conventional problem of dimensional stability of the braid, it is sufficient to suppress the elongation of the braid.
As a means for this, by inserting a fiber bundle or tape-like cloth 66 that suppresses elongation into the core separately from the braid structure, the dimensional stability of the braid is ensured and the fit of the braid to the molded shape is not impaired. By acting as a directional reinforcing material, the same effect as that of the triaxial braid can be obtained.

In the continuous manufacturing method of such a braided preform, high productivity, labor saving, homogeneity, easy resin impregnation, a wide selection of resin raw materials, a large degree of freedom in designing molding materials,
Various effects such as good handleability, good dimensional stability, good surface quality of molded products, omission of post-correction processing, high quality, and low cost can be obtained.

When forming a bent pipe or a racket preform having a predetermined shape, it is possible to dispose a core material made of a honeycomb body or wood in at least a part of the tubular preform. For example, as for the racket frame, as shown in FIG. 22 and FIG.
The honeycomb structures 73 and 74 are arranged inside the structure to form a sandwich structure. As a result, it is possible to prevent buckling due to gut tension (increase in gut pull-out strength), reduce weight, and increase rigidity. Honeycomb bodies 73, 7
The position where 4 is arranged is outside (FIG. 22) in the case of anti-gut pull-out strength, and is in the vertical cross section in the case of improving rigidity (FIG. 23).

The yoke portion of the racket can also be constructed in the same manner. That is, a conventional yoke is one in which a foam material such as EVA (ethylene vinyl alcohol) sheet is arranged on both sides of a urethane foam, and a prepreg is wound around the foam material, and is molded by heating (EVA foaming) and curing during frame molding. It was the mainstream. However, in this method, since the internal pressure is not sufficient and the urethane foam as the core has almost no reinforcing effect, it is necessary to thicken the FRP layer, which leads to an increase in weight.

Therefore, as shown in FIGS. 24 and 25, the honeycomb bodies 77 and 78 are arranged inside the yokes 75 and 76,
Buckling due to the tension of the gut 79, 80 is prevented. The location where the honeycomb bodies 77 and 78 are arranged is basically such that the honeycomb body is in contact with the outer shell, and it is advisable to use a foaming material together for molding. If a powdered or granular material is used as the foam material, a sandwich structure can be formed in contact with the inner shell (ball striking face side).

Next, the shaping of the preform will be described. The long preform formed as described above is preshaped according to the shape of a bent tube, for example, a racket, before being molded into an FRP.

For example, before mounting the racket molding base material in the cavity of the racket molding die, a mold having a substantially cavity shape, for example, a mold having a convex portion having a shape along the shape of the cavity ( For example, using a wooden pattern)
It is a method of pressing the molding base material against the outer periphery of the convex portion with a pair of pressing rollers while applying tension to the molding base material, and shaping the molding base material into a shape along the shape of the convex portion.

More specifically, as shown in FIG. 26, a predetermined prepreg, a reinforcing fiber sheet 82, etc. are wound on a tubular film 81, and if necessary, the above-mentioned nonwoven fabric layer (not shown). A long preform 83 coated with
This is a method of imparting (holding) tension to both outer sides in the length direction and shaping along the convex portion 85 of the mold 86 having the convex portion 85 to which the yoke part preform 84 is mounted in advance.

This shaping can be performed using an automatic shaping machine 90 as shown in FIG. 27, for example. In the figure, reference numeral 91 denotes preform guides provided on both sides, and a pair of tension holding mechanisms 92 are used to form the preform 83.
Tension is applied (held) during shaping. Reference numeral 93 denotes a pair of pressing rollers. The preform 83 is symmetrically arranged by the air or hydraulic cylinder 94, and the wooden pattern 86 is formed.
It is pressed against the outer circumference of the convex portion 85.

First, as shown in FIG. 27, the straight and flat preform 83 is placed at the preform set position. Then, the H-shaped yoke part preform 84 is attached to the mold 86.
Place it at the yoke set position of. At this time, the mold 86 and the pressing roller 93 are in the initial positions. The tension holding roller 92 holds the tension by sandwiching the preform 83.

Next, as shown in FIG. 28, the die 86 moves forward, hits the preform 83, and the pressing roller 93 pushes the preform 83 against the convex portion 85 of the die 86, thereby projecting the preform 83. Bend according to the portion 85.

The mold 86 is further advanced, and as shown in FIG. 29, the pressing roller 93 presses and adheres the preform 83 to the yoke preform 84 arranged at the yoke set position.

Then, as shown in FIG. 30, the preforms 83 overlap with each other at the grip roots and are pressed by the pressing rollers 93 to strongly adhere the grip roots, and then the pressing force of the pressing rollers 93 is changed to the pressing force switching mechanism ( (Not shown) to weaken.

By further moving the die 86,
As shown in FIG. 1, the preform 83 presses against the pressing roller 9
The grip portion 95 is adhered by moving while being sandwiched between the three.

The mold 86 moves to the end of the line and stops (see FIG. 3).
2). The preform 83 is taken out from the mold 86, and the pressing roller 93 and the mold 86 return to the initial position. The shaped preform is put into a mold after a person applies a prepreg to the adhesive portion to reinforce it, and then pressure-heated and molded.

In the above, the pressing roller 9
The pressing force of No. 3 is switched by a switching mechanism (for example, switching of the driving pressure of the air cylinder). This prevents the preform 83 from wrinkling and strongly adheres the yoke portion 84 until the grip portion adhering step. For,
This is because the pressing force of the roller is increased and the pressing force of the roller is weakened in order to prevent the grip root from being peeled off by the tension in the grip part adhering step.

Further, the mounting angle of the air cylinder 94 of the pressing roller 93 is within the range of 45 to 90 ° with respect to the machine shaft 96 in order to prevent wrinkles near the top part and to improve the adhesive strength of the yoke part and the grip part. Is desirable.
When comparing this angle with 45 °, 75 °, 90 °,
At 45 °, a sufficient force does not act in the direction in which the pressing roller 93 presses the preform 83 against the mold near the yoke and grip. At 90 °, the pressing roller 93
Since the position where the preform 83 starts to be pressed is retracted, the function of preventing the generation of wrinkles on the inner peripheral side of the preform at the top portion is not fulfilled. To prevent wrinkles from occurring on the top part and to improve the adhesive strength of the yoke and grip parts, 7
Most suitable is 0 to 80 °.

The pressing mechanism for the pressing roller 93 may be a mechanism other than the illustrated air cylinder. In addition to the linear reciprocating motion of the cylinder, the mechanism becomes complicated, but the pressing direction of the pressing roller may be changed by the link mechanism according to the curve of the mold. Further, it is desirable that the surface of the roller is subjected to a tack-resistant treatment such as Teflon coating.

In the tension holding mechanism 92, a pair of tension holding mechanisms 92 are arranged symmetrically with respect to the machine shaft 96 at the preform set position. As a more detailed mechanism, FIG.
As shown in FIG. 3, the movable roller 98 is composed of a fixed roller 97 and a movable roller 98, and the movable cylinder 98 is moved by the air cylinder 99 to hold the tension by sandwiching the preform 83. Fixed roller 9
The tension of both the moving roller 98 and the moving roller 98 can be adjusted by regulating the rotational force with the band brake 100.

As the mold 86, a convex portion 85 in the shape of a racket frame is formed on a rectangular plate (an elliptical portion in the shape of a gut surface and a triangular portion from the yoke portion to the grip base).
Has a protruding structure. As shown in FIG. 26, an H-shaped yoke part preform 84 can be set between the elliptical part and the triangular part.

The mold 86 is on the axis of the apparatus, and moves on the axis from the position before the preform setting position to the line end where the shaping is completed. Driving is performed by converting the rotational movement of the motor into a linear movement with a ball screw, but other driving methods are also possible. It is desirable that the surface of the mold 86 on which the preform 83 contacts is subjected to a non-adhesive treatment (Teflon coating or the like). Otherwise, after shaping, preform 83
It becomes difficult to take out the mold from the mold 86, and the shape may be lost.

In the actual racket frame, the vicinity of the yoke portion is recessed. However, when a mold is created with the shape kept as it is, the preform 83 and the yoke portion which have been once adhered to each other due to the tension applied to the preform 83. Preform 84
May peel off. Therefore, the shape of the mold is a little broken, and the vicinity of the yoke is linear (Fig. 34).
Alternatively, it is preferable to make the shape bulge outward.
If the position of each adhesive is correct, there is no problem even if the curvature of the curve is slightly different from the actual curvature.

The pressing force of the pressing roller 93 is, for example, the drive pressure of the air cylinder 94, which is determined by a solenoid valve (not shown).
You can switch by switching with. For example, the larger pressure is 4kgf / cm ²
And the smaller pressing force may be set to about ² kgf / cm ² .

Conventionally, a straight flat preform made by winding a plurality of prepregs around a core material coated with a resin or rubber tube was manually wound around a wooden mold in the shape of a racket frame. The yoke part and the grip part were adhered. In such a method, when the preform is bent according to the mold, wrinkles are likely to occur on the inner peripheral side, and therefore it is necessary to bend while pulling both ends of the preform. Therefore, there are problems that the operator is tired, that strong tension cannot be applied by the force of a person, and that the tension is not constant. Also, at room temperature, the flexibility of the preform is low, and it is difficult for human power to bend it according to the mold, so heat the preform with a hot plate to make it easier to bend according to the mold. Was softening. Therefore, since the preform is soft, there is a problem that the shape is likely to collapse when bent or taken out from the mold, and handling is troublesome (high adhesiveness), so that defective products are likely to be produced. In addition, it takes time, work efficiency is poor, and because it is manual, it is not uniform and quality variations occur,
There was also such a problem.

By using the automatic shaping apparatus and method as described above, both ends of the preform, which has a certain degree of rigidity even at room temperature (25 to 35 degrees), are bent according to the die while being pulled by a tension holding mechanism with a strong force. It is possible to prevent the generation of wrinkles on the inner peripheral side of the preform.

By forming the preform while pressing it against the mold with the pressing roller, it is possible to prevent the generation of wrinkles on the inner peripheral side of the preform,
The adhesion of the grip portion can also be performed in a preferable state.

Further, since the preform is shaped at room temperature, the tackiness of the preform is not high, but the preform has a certain degree of rigidity. Can hold.

Further, it becomes possible to stabilize the quality, improve the yield, shorten the molding time, save labor and improve the work efficiency.

Next, a method of manufacturing the FRP bent pipe and the FRP molded product of the racket according to the present invention will be described. First, in the method for manufacturing a bent pipe or racket made of FRP according to the present invention, a molding base formed by covering a flexible tube covered with a tubular film with a prepreg of reinforcing fiber is put in a cavity of a mold, Is heated and the inside of the flexible tube is pressurized to 30 kg / cm ² · G or more, and the molding substrate is pressed against the mold.

On this prepreg, the single yarn diameter is 20 μm.
It is preferable that a non-woven fabric having a weight of 100 m / m ² or less and a weight of 100 g / m ² or less is wound around the fabric.

Such a method is one of the so-called internal pressure molding methods, but the load pressure is 30 k.
Since it is g / cm ² · G or more, which is much higher than the normal pressure, it is particularly referred to as “high pressure molding method” in this specification.

That is, as described in the section of the prior art,
Conventionally, internal pressure molding has been performed at a relatively low pressure by mainly using a compressive fluid (for example, air). The high-pressure molding method according to the present invention uses, for example, a flexible tube in which one end is closed and the other end is connected to a joint for introducing a pressurizing medium made of an incompressible fluid from an external pressurizing device. The flexible tube is expanded in a leak-free state, and the molding base material is expanded to perform molding.

Such a method is carried out using the following device. That is, the FRP bent pipe or racket manufacturing apparatus according to the present invention includes a mold having a cavity in which a molding base material obtained by coating a tubular film covered with a flexible tube with a prepreg of reinforcing fibers is placed, 30 kg / consisting of incompressible fluid in the flexible tube
and a pressurizing medium supply means for supplying a pressurizing medium of cm ² · G or more.

Here, the flexible tube is made of a heat-resistant material whose strength is such that even if it is heated to the curing temperature of the thermosetting resin, it will not be broken by the force during molding. The hardness is preferably 80 (JIS
A) The following silicone rubbers and fluororubbers are preferable, and a silicone rubber tube having a hardness of 40 (JISA) is more preferable for obtaining sufficient elongation. In addition, it is convenient to remove the tube after molding if the tube cross-sectional shape is similar to that of the molded product if possible. The outer dimensions of the tube are such that the tube can be easily pulled out from the molded product after molding.
Specifically, in consideration of the limit elongation rate of the tube, one having a cross section of the inner wall of the mold of about 50 to 80% is preferable.

As a method of closing one end of the tube, other than a method of molding one end in a closed state at the time of manufacturing,
Examples include a method of adhering, a method of narrowing one end of a tube whose both ends are open, for example, with a wire, a method of setting the tube in a bent state in a mold and closing the tube by pressing force of the mating surfaces, and the like.
On the other hand, the other end of the flexible tube improves the rigidity of the caulked portion by forming the double-structured portion of the tube, and the wall thickness of the tube is 40 to 70 with respect to the wall thickness before processing. %, More preferably 50 to 60%. Silicon rubber, fluororubber, hard rubber, metal blades, and the like are preferable as the reinforcing member for forming this double structure.

The non-compressible fluid filled in the tube does not vaporize at the curing temperature of the thermosetting resin, and
Those that do not cause deterioration of physical properties during long-term use are preferable.
Specifically, for example, turbine oil, silicone oil or the like can be used, and among these, inexpensive and easily available turbine oil is preferable. These non-compressible fluid, at least 30kg / cm ² · G or more pressure inside the flexible tube, preferably pressurized to a pressure of 70~100kg / cm ² · G. Such pressure, especially at least 30 kg / c
The reason for pressurizing to a pressure of m ² · G or higher is based on the results of visual tests after the coating of the surface recesses performed by the inventors. That is, by pressing a needle-shaped object with a diameter of 0.1 mm to 1.0 mm against the surface of an aluminum plate,
When the size of the recesses that can be observed with the naked eye after coating the aluminum plate is provided, the recesses of m units are provided, and those having a diameter of 0.3 mm or less have almost no effect on the surface quality, but 0.4 m
Defects became observable at 0.5 mm with m as the boundary. From this, the pressure p required to compress a defect having a diameter of 0.5 mm to a diameter of 0.3 mm is p / p ₀ = (0.5 / 0.3) ³ . Here, p ₀ is a molding pressure of about 7 according to the prior art.
Assuming kg / cm ² · G, p is at least about 30 kg /
cm requires a pressure of G or more. On the other hand, the upper limit pressure is not particularly limited, and the higher it is, the more preferable it is from the viewpoint of preventing surface defects, but it is 150 kg / cm ² · G from the viewpoint of practicality.

The reason why the tubular film is inserted into the outer circumference of the flexible tube is that the molded product can be easily pulled out from the flexible tube after the hollow tube made of fiber reinforced plastic is molded. . Therefore, in order to prevent melting when the mold is heated, it is preferable to use, as the material of the tubular film, a material having a melting point higher than the heating temperature by 30 to 40 ° C. or more, for example, a material such as polyamide or PET.

An embodiment of the above method and apparatus will be described with reference to the drawings. FIG. 35 is an overall perspective view of the flexible tube 101 used in the method of the present invention.
01 is inserted into the tubular film 102, and the fiber reinforced sheet 103 (prepreg) is further wound around the outer periphery of the film 102. A molding substrate 104 (preform) is obtained by winding the prepreg 103 around the outer periphery of the film 102.

In carrying out the method of the present invention, the state shown in FIG. 35 must first be prepared as a preliminary step. The specific steps are as follows. First, a core material such as wood, bamboo, or plastic (not shown) is inserted into the tubular film 102 made of polyamide. Then, the fiber reinforced sheet 10 in which the outer periphery of the film 102 is preliminarily impregnated with a thermosetting resin such as an epoxy resin or a phenol resin which is a thermosetting resin according to the intended use.
3 (prepreg) is wound a predetermined number of times and laminated, after which the core material is extracted and the flexible tube 101 is inserted.

In this embodiment, as the tubular film 102 on the core material, a polyamide film having a wall thickness of 0.1 mm is used. The fiber-reinforced sheet 103 is a so-called prepreg, and in the present embodiment, carbon fibers, which are reinforcing fibers, are impregnated with an epoxy resin.

As shown in the overall view of FIG. 36, the flexible tube 101 has an outer shape of 13 mm and a hardness of 40 (JISA).
Cut the silicone rubber tube of to 1800mm in length,
The right end portion was closed by bonding, and the left end portion was connected to a male side joint 106 of a commercially available one-touch coupler joint so that it could be connected to an external pressure device (not shown). That is, as shown in FIG. 37, which is an enlarged partial sectional view of the joint 106, the left end of the flexible tube 101 is connected to the tube 1
In order to prevent liquid leakage from 01 and improve rigidity, a reinforcing ring 114 is fixed to the inner circumferential surface of the tube to form a double structure, and the outer circumference of the tube end of this double structure is caulked ring 1.
With No. 13, the tube thickness after crimping was processed to be 55% of the wall thickness before crimping.

Next, the flexible tube 10 described above.
A procedure for manufacturing a hollow bent tube, specifically, a racket frame using No. 1 will be described with reference to FIG. Figure 38
In the drawing, 115 is an external pressurizing device connected to the male joint 106 of the flexible tube 101 via a pressure-resistant hose 112, and both ends of one rod 119 in two hydraulic cylinders 117 and 118. Piston 12 fixed to
This is a so-called dual type cylinder / piston device in which 0 and 121 move forward and backward. In the pressurizing device 115, the pressure oil produced by the hydraulic pump 122 is supplied to the pipe 123.
When the cylinder 117 is filled via the switching valve 109 and the switching valve 109, the common rod 119 moves to the right and the cylinder 1
The turbine oil 105 in 18 is filled in the tube 101 by the piston 121 via the valve 110, the pressure resistant hose 112, and the joint 106, and the tube 101 is expanded. In addition, the tube 101 is the film 1
When pulling out from 02, the common rod 119 is moved leftward in advance so as to be contracted, and then pulled out. In addition, 111 is a pressure gauge for confirming the filling pressure.

In the present embodiment, as the mold 107, a mold comprising a lower mold 107a whose cavity has a racket frame shape as shown in the figure and an upper mold 107b fixed to the upper part of this lower mold is used. . First, the molding substrate 104 in the state shown in FIG. 35 was mounted along with the flexible tube 101 along the cavity of the lower mold 107a as shown in FIG. 38, and then the yoke 108 was mounted. The tube 10
One end of No. 1 was protruded from the cavity and placed on the mating surface of the lower mold as shown in the figure. In this case, if the temperature of the mold is kept at 40 to 60 ° C. in advance, the fiber reinforced sheet 1
Since 03 is softened, it becomes very easy to mount. Then, the upper and lower molds 107a and 107b were clamped by a hot press machine (not shown) to integrate the molds 107a and 107b, and the tube tip 116 was closed by the mating surfaces of both molds. After that, the external pressurizing device 115
From the turbine oil from 100kg / cm ² ·
The base material 104 is pressed to the film 10 by applying pressure up to G pressure.
It was inflated together with 2 in the cavity of the mold and strongly pressed against the inner wall surface of the cavity.

Next, the mold 107 was heated to 150 ° C. to cure the epoxy resin, the turbine oil was extracted to the outside to release the pressure, and then the molded product was taken out from the mold 107. And finally, from the molded article to the flexible tube 10
The target FRP racket frame was obtained by pulling out 1.

According to such a manufacturing method, the incompressible fluid having an unprecedentedly high internal pressure can be molded without leaking from the flexible tube. It is possible to manufacture a bent pipe and a racket frame made of FRP, which are excellent in quality and have no surface defects due to poor pressure welding.

As the structure of the joint portion of the flexible tube in the above-mentioned high-pressure molding method, other than that shown in FIG. 37, FIG.
As shown in FIG. 9, the flexible tube 125 may have a thick structure at the connection portion 124 with the joint 106. Then, the tube wall thickness t of the connecting portion 124 and the wall thickness t0 of the tube 125 in a portion other than the connecting portion have a relationship of t> t0, and preferably the tube wall thickness after caulking is If t ', 0.4 <(t-
It is desirable to adopt a configuration of t ') / t <0.7. Hereinafter, [(t−t ′) / t] × 100 is referred to as a crimping rate.

The end portion of the flexible tube improves the rigidity of the caulking portion by making the tube of the caulking portion have a double structure or the above-mentioned thick structure, and
The crimping rate is preferably 40 to 70%, more preferably 50 to 60%. Silicone rubber, fluororubber, hard rubber, metallic blade and the like are preferable as the reinforcing member for forming the double structure.

Although the above-mentioned method has been described as a so-called high-pressure molding method, the bent pipe or racket made of FRP having the nonwoven fabric layer according to the present invention is a normal internal-pressure molding method, that is, a method of applying a relatively low internal pressure. But it can be manufactured.

That is, in the method for producing a bent pipe or racket made of FRP according to the present invention, a tubular film is coated with a prepreg of a reinforcing fiber, and a single yarn diameter is 20 μm or less and a basis weight is 100 g on the prepreg. Characterized in that a molding base material formed by winding a non-woven fabric of less than 1 / m ² is put into the cavity of the mold, the mold is heated, and the inside of the tubular film is pressed to press the molding base material to the mold. And the method.

In the above method, the non-woven fabric is also preferably prepregized.

Even with such a normal internal pressure molding method,
By providing the above specific non-woven fabric layer on the outer layer of the molding substrate, as described above, good fluidity and deaeration of the resin at the time of molding are secured, and voids, pinholes, and resin flow are ensured. It is possible to obtain a molded product having good surface quality and having no defective parts.

In the high-pressure molding method or the normal internal-pressure molding method as described above, in order to improve the ease of molding and the ease of demolding, the mold is divided into upper and lower dies and a core that is configured to be separable. It is preferable to use a mold that contains That is, the fiber-reinforced plastic bent pipe or racket manufacturing apparatus according to the present invention is a mold of an upper and lower split type having a cavity in which a molding substrate formed by coating a tubular film with a prepreg of a reinforcing fiber is placed, A pressurizing medium supplying means for supplying a pressurizing medium into the tubular film,
In addition, the lower die includes a core that is configured to be separable. Such a device can also be applied to the RTM method described later.

Further, in the FRP bent pipe and racket according to the present invention, the reinforcing fiber sheet is wound around the outer periphery of the tubular film, and the resin is injected after being mounted in the mold.
It can also be manufactured by the Resin Transfer Molding method (hereinafter sometimes abbreviated as RTM method).

That is, in the method for manufacturing a bent pipe or racket made of FRP according to the present invention, the tubular film is coated with the reinforcing fiber, and the coating layer of the reinforcing fiber has a single yarn diameter of 20 μm or less and a basis weight. Of a non-woven fabric of 100 g / m ² or less is put into a cavity of a mold, the mold is heated, and the inside of the cavity is depressurized while depressurizing the inside of the cavity. The method comprises injecting a resin.

In this method, since the reinforcing fiber layer of the molding substrate is impregnated with resin, it is not necessary to make it into a prepreg, but it is possible to make a non-woven fabric into a prepreg.

More specifically, this method is, for example,
A preform in which reinforcing fibers are formed in a tubular shape and a molding base material in which a flexible tube is arranged in the inner layer are set in a mold heated to the molding temperature, and the flexible tube is pressurized and simultaneously the cavity is depressurized. The resin is injected into the mold at an injection speed of 1 to 7 g / sec and an injection pressure of ² to 15 kgf / cm ² , and the resin is cured in 5 minutes or more and 20 minutes or less.

In this method, the preform is preferably made by filament winding or braiding, and a molding substrate having a flexible tube as an inner layer is used. The molding substrate is bent and put into a lower mold having a cavity having a desired bent tube shape, for example, a racket frame shape. At this time, in order to pressurize the inside of the tube later, one end of the tube is tightly bound to close it, and a coupler for introducing a pressurized medium such as compressed air is attached to the other end. Next, the upper mold is closed, and 0.5 to ² kgf / cm ² is placed in the flexible tube.
Resin is injected while introducing pressured air.

The mold for setting the molding base material has an effect that the molding cycle can be shortened and the molding cost can be reduced by raising the temperature near the molding temperature in advance, and that the viscosity of the injected resin can be lowered and the impregnation property can be improved. There is. Further, by setting the molding substrate in the lower mold and depressurizing the cavity of the mold in which the upper mold is closed, the impregnating property of the injected resin into the substrate and the surface property of the molded product are improved. As a method of depressurizing, resin may be injected while pulling the cavity with a vacuum pump, or by pulling the cavity with a vacuum pump and then closing the depressurizing port of the mold and injecting resin into the cavity where the pressure is reduced. But it's okay. However, it is preferable that the cavity has a sealing property such that the time of holding 300 Torr or less is 3 minutes or more in a state where the depressurized state is not pulled by the vacuum pump and the resin is not injected. If it is within 3 minutes, bubbles are likely to be entrained during the resin injection, and the surface properties and resin impregnability are deteriorated.

Examples of the resin used include thermosetting resins such as epoxy resin, unsaturated polyester resin, vinyl ester resin and phenol resin. The viscosity of these resins is preferably 50 centipoise or more and 10 poises or less in the temperature state at the time of injection. If it exceeds 10 poise, the flow resistance due to the molding base material at the time of injection is large and impregnability and handleability are deteriorated. On the other hand, if it is less than 50 centipoise, it causes resin leakage from the mold and is not preferable.
The temperature of the injected resin is preferably between room temperature 25 ° C. and 70 ° C. At 70 ° C or higher, the viscosity tends to increase due to the curing reaction. However, it is necessary to select an appropriate temperature because there is a difference depending on the type of curing agent.

The time required for injecting the above resin is preferably 1 to 5 minutes. If it is less than 1 minute, the injection pressure becomes high, and the arrangement of the molding base material is disturbed, the resin leaks from the mold, and the impregnation is likely to occur. If it is more than 5 minutes, the curing reaction of the injected resin proceeds and the viscosity becomes high, which is not preferable. The injection method may be continuous injection or intermittent injection.
In the case of intermittent injection, the time from the start of injection to the end is the injection time. The resin injection pressure at this time is 2 to 15 kgf / c
It is preferably m ² . Furthermore, if the pressure inside the flexible tube is increased to 5 to 6 kgf / cm ² during molding, excess fat can be squeezed out, the content of reinforcing fibers increases, and the uniformity of the wall thickness is improved to improve physical properties. It becomes possible to obtain a better bent pipe.

As the preform, one obtained by filament winding or braid is used. In the filament winding method, a mandrel is covered with a flexible tube, for example, a rubber tube or a nylon tube, and a reinforced fiber bundle is formed around the tube by a filament winding method, for example, a fiber bundle made of carbon fiber, glass fiber, polyaramid fiber. Is preferably ± 7 to 75 with respect to the axial direction of the mandrel.
Helical winding is performed in the range of ° to form a helically wound layer of arbitrary thickness. The reinforcing fiber bundle may be in the form of a strand or a tape. Also,
If the winding angle is smaller than 7 °, the stability of the arrangement of the reinforcing fiber bundles is lowered, and if it exceeds 75 °, the tightening force becomes strong and it becomes difficult to pull out the mandrel afterwards. further,
The reinforcing fiber bundle is preferably wrapped while applying a force of 50 to 200 g. The braid is a tubular braid of the above-mentioned reinforcing fiber bundle, and the above-mentioned flexible tube is arranged in the inner layer thereof. The flexible tube is arranged by covering the fixed mandrel with the tube, and then braiding the mandrel so that it has a predetermined thickness. At this time, the braiding angle of the braid is set so that the reinforcing fiber bundles are arranged at an angle of 20 to 30 ° in a state where the tube is expanded by applying pressure to the tube.

When the above molding substrate is set in the cavity of the lower mold, it is also possible to additionally set a cloth using reinforcing fibers to partially reinforce and improve the rigidity. In particular, for a racket frame such as a tennis racket frame, reinforcement around the hole is preferable also for preventing the gut hole from sinking. In addition, the surface of the molded product is apt to be deteriorated due to the disorder of the molding base material at the joining portion of the racket frame with the yoke portion and the portion where the two molding base materials merge from the frame to the grip portion. It is also preferable to wind a cloth made of reinforcing fibers around this portion and additionally set.

The heat resistance of the molded product must have Tg (glass transition temperature) of 130 ° C. or higher. This is important to prevent deformation at high temperatures. For this reason, the Tg of the molded product that has been molded and released from the mold is 11
It is preferably 0 ° C. or higher. If the temperature is 110 ° C or lower, T of 130 ° C or higher, which is necessary for a tennis racket frame
It is difficult to obtain g by after-cure.

In the RTM method as described above, normally,
In order to sufficiently impregnate the reinforcing resin with the injected resin, it is general to use a resin having a low viscosity. However, when the viscosity is low, there is a problem that the resin is likely to leak from the parting surface of the mold. The resin leakage at the time of injection not only impairs the quality of the molded product but also deteriorates the surrounding work environment. In addition, vacuuming the cavity during resin injection has the effect of improving resin impregnation and lowering the injection pressure, but if the parting surface and injection port are not well sealed at that time, the outside air will leak into the cavity and cause voids. There was a problem that became.

Therefore, it is desirable to use a mold that does not leak resin and that has excellent sealing properties when evacuated, and that is excellent in moldability and mold release. To meet this demand, an FRP bent pipe or racket manufacturing apparatus according to the present invention comprises an upper and lower split mold having a cavity for accommodating a molding base formed by coating a tubular film with reinforcing fibers, A pressurizing medium supplying unit for supplying a pressurizing medium into the tubular film, a depressurizing unit for depressurizing the inside of the cavity, and a resin injecting unit for injecting resin into the cavity, and The mold is characterized in that it contains a core that is configured to be splittable.
Further, it is preferable that a sealing material is arranged around the cavity. Further, it is preferable to have a resin pool on one side or both sides of the cavity.

That is, the moldability and the ease of demolding are improved by the structure in which the upper and lower split molds and the splittable core are contained, and the resin leak is prevented by the provision of the sealing material, and at the time of depressurization. The sealing property of is improved. Further, by providing the resin reservoir, the bubbles in the cavity move to the resin reservoir together with the resin, and the bubbles in the resin used for molding are reduced to prevent the occurrence of voids and the like.

For example, the mold is a split mold of an upper mold and a lower mold, and two or more resin injection ports and decompression ports are provided in combination. Further, at one end of the bent pipe, a pressurized gas is applied to a tube arranged in the cavity. It is provided with one port for blowing pressurized air. It is preferable to arrange a continuous sealing material on the outer periphery of the cavity of the mold. Seal material is 150
It is preferably made of a silicone resin or a fluororesin that can withstand a high temperature of ° C and has a circular or flat cross section. Make a groove on the parting surface of either the upper mold or the lower mold or leave it as it is and seal with the tightening force when the mold is closed. In this case, if the sealing property is good, there may be a problem that the injected resin bubbles will not come out of the cavity. For this reason, if a groove for resin accumulation is provided between the cavity and the sealing material, bubbles inside the cavity Has the effect of moving to the resin pool and reducing bubbles in the resin. The size of the groove is 5 to 15 mm wide and 1 to 5 mm deep along the cavity.
Is preferably provided on the outer peripheral side, and more preferably on the inner peripheral side.

The resin injection port and the decompression port are preferably provided in two or more places in total, and the decompression port also serves as a resin extraction port. It is preferable that all the openings are provided in the cavity in the shape of slits so that no marks are visible on the surface of the molded product. Also, depending on the conditions, the inlet and the decompression port can be changed to each other,
Furthermore, if three or more ports are used in combination, the molding conditions can be optimized.

It is preferable that a resin reservoir is provided between the resin injection port and the pressure reducing port to reach the cavity. A slit gate is provided from the resin reservoir to the cavity, and resin is injected from the gate to the cavity or the pressure is reduced. Since the depressurizing port is also a port through which the injected resin escapes, a resin reservoir similar to the injection port is preferable. By providing such a resin reservoir, it becomes easier to install a slit gate in the opening leading to the cavity, and it is possible to make the gate mark invisible on the surface of the molded product after curing. The resin puddle is 3 ° ~ so that the resin will come out of the mold at the same time when the mold is opened.
It is preferable to provide a draft angle of 15 °. It is preferable that the plugs attached to the inlet and the pressure reducing port have a cross-sectional shape that allows the shearing force to be transmitted to the cured resin and screwed by rotating the plug after curing the resin.

In the end portion of the bent pipe according to the present invention, for example, in the racket frame, a portion corresponding to a grip portion has a compressed gas blowing port for loading an internal pressure. The internal pressure is applied by placing an extensible tube in the core portion of the intermediate base material (preform) made of reinforced fibers and blowing compressed air such as air through the nozzle opening of the blowing opening. Since the compressed gas is blown into the cavity through the tube, it is necessary to prevent the gas from leaking into the cavity. For this,
It is preferable to provide a blowing nozzle that covers a tube having a tapered nozzle and inserts the tube into a flange having the same taper to seal the tube. The nozzle diameter at this time is preferably a taper diameter which is ± 5% of the tube diameter. Further, since the tube has a large rate of expansion to the volume of the cavity at the blow-in portion on the cavity side, it is easy to burst when the internal pressure is applied. To prevent bursting, taper the cavity side so that the diameter of the cavity gradually becomes smaller than the diameter of the flange hole. Taper length is 1
~ 5 cm is preferred.

With the above-mentioned mechanism, it is easy to maintain the reduced pressure state in the cavity at -500 Torr or less for 3 minutes or more when the reduced pressure state in the cavity is not pulled by the vacuum pump and the resin is not injected. It can have a sealing property. If it is within 3 minutes, bubbles are likely to be entrained during the resin injection, and the surface properties and resin impregnability are deteriorated. Further, the sealing property of the cavity is preferably a sealing property of keeping -500 Torr or less for 5 minutes or more in a closed state.

More specifically with reference to the drawings,
40 and 41 show a mold 130 including an upper mold 131 and a lower mold 132, and a resin injection port 133 and an air supply port 13 are shown.
4. A decompression port 135 is provided. A sealing O-ring 137 is arranged on the outer periphery of the cavity 136 for sealing the mold 130. In order to provide high sealing property, the sealing material 1 is seamlessly provided around the cavity 136.
Surrounding by 37 is required.

The resin injection port 133, the decompression port 135, and the air supply port 134 are arranged at a total of three or more places, and the injection port and the decompression port can be arbitrarily exchanged. Decompression port 1
Reference numeral 35 is also a resin outlet.

The resin injection port 133 and the pressure reducing port 135 are constructed, for example, as shown in FIG.
Through to the cavity 136. Reference numeral 139 is a storage core, and 140 is a slide core. The slide core 140 is installed on the outer periphery of the cavity 136, and is provided for removing the undercut portion (gut portion of the tennis racket) from the mold and for accommodating the bulky base material so as not to be caught. There is.

The cavity 1 is used as a resin reservoir for removing bubbles.
A resin reservoir 141 of overflow resin is installed on one side or both sides of 36. As a result, the resin that has overflowed after the resin injection can be stored, and the resin overflows together with the air bubbles, so that the voids in the molded product can be reduced. This is effective because it is difficult to remove the sealing material around the cavity from the outside.

Further, as shown in FIG. 42, it is also effective to install the resin reservoir 142 for the gate between the inlet and the pressure reducing port and the gate. By providing the resin reservoir 142, the injection plug can be easily attached to the slit gate injection port 133. Further, even if the injection pressure of the resin supplied from the outside fluctuates, it is buffered and the cavity 13
It is difficult to reach 6. By providing the resin pool 142 with a draft as shown, removal of the cured resin therein is easy.

A plug 143 as shown in FIG. 43 is used for the resin injection port 133 and the pressure reducing port 135.
The cured resin in the plug 143 and the cured resin in the resin pool are threaded by a shearing force. The central axis 144 of the plug 143
By turning it around, the cured resin is threaded by the shearing force generated on the plane 145.

In order to easily generate this shearing force, FIG.
The shape of the pipe portion viewed from the direction A of FIG. 3 is not only a normal simple pipe, but also a pipe shape 146 having an elliptical mouth shown in FIG. 44, a pipe shape 147 having a polygonal mouth shown in FIG. 47 has a square shape with a square mouth, 149 has a rectangular shape with a shape shown in FIG. 47, 149 has a semi-circular shape with a shape shown in FIG. It may be a tubular shape 152 having a mouth divided into two semi-circular mouths shown in FIG. Also,
These tubular shapes may be formed only at the mouth of the plug or may be formed over the entire length of the plug.

Regarding the internal pressure blowing port (air supply port 134), as shown in FIG.
Is installed at one location on one end of the mold. A nozzle 153 and a mounting flange 154 for blowing compressed air into the tube from one end of the bent tube are provided. The tube for loading the internal pressure is put on the nozzle 153, inserted into the flange 154 as it is, and pressure-bonded with the gradient provided on the nozzle 153 and the flange 154, and then fixed to the mold 130 in that state. Since the tube expands greatly near the entrance of the cavity of the internal pressure blowing port 134 and is likely to burst, it is preferable that the cavity have a gradient 155 to change the internal volume of the cavity in a tapered shape as shown in FIG.

Further, the relationship between the slide core 140 and the storage core 139 described above is as shown in FIGS. 53 to 55 (shown in the order of operation at the time of mold matching).
The molded base material 156 mounted on the 36 is housed so as not to be bitten, and the undercut portion (the racket gut tension portion) can be easily demolded.

The FRP bent pipe or racket according to the present invention can also be molded by a so-called air vent molding method in which excess resin and air in the cavity are naturally expelled during molding.

For example, a prepreg is wound around the outer circumference of a tubular film, and the single yarn diameter is 20 μm on the outer circumference of the prepreg.
Then, a molding substrate wound with a non-woven fabric having a basis weight of 100 g / m ² or less is mounted in the cavity of the mold, the mold is heated, and the cylindrical film is pressurized to expand the molding substrate. This is a method in which the resin is pressed against the mold and the excess resin of the molding base material and the air in the cavity are caused to flow out of the cavity during the pressing. Also in this method, the non-woven fabric layer is preferably prepregized.

The above method can be carried out by the following device. For example, a mold having a cavity for mounting a molding base material having a prepreg wound around the outer periphery of a tubular film, and a pressurizing medium supply means for supplying a pressurizing medium into the molding base material, and The apparatus is provided with a slit-shaped discharge path communicating with the outside of the mold, which allows the mold to discharge the excess resin of the molding base material and the air inside the cavity to the outside of the cavity.

The above method and apparatus are intended to solve the following conventional problems. That is,
Conventionally, for example, as shown in FIG. 56, a molding base 164 is mounted in a cavity 163 formed by an upper mold 161 and a lower mold 162, and a slide core 165 and the like are arranged to form an FRP.
When molding a molded product by internal pressure molding (166 is a mating surface), a relatively low pressure (for example, compressed air of 8 kg / cm ² ) is applied, so that insufficient adhesion of the molding base material 164 to the cavity occurs and the air inside the mold is completely removed. It may not come off (adhesion failure part 16
7). Such poor adhesion causes surface defects (occurrence of concave portions) and generation of voids. Further, this defective portion characteristically occurs depending on the mold due to the shape of the hollow tube (it tends to occur at a specific portion).

Therefore, as shown in FIG. 57, by providing a slit 168 at a defective portion due to the air being not released, the air trapped at the portion is not affected by the resin flow and the product quality (for example, gold). It is carried away (outside the mold) to improve the adhesion.

The slit 168 can be machined by an end mill or the like, but die-sinking electric discharge machining or wire cut electric discharge machining is preferable. The width of the slit 168 is preferably 0.3 to 0.7 mm. If it is less than 0.3 mm, the processing is difficult and the resin does not easily flow, and if it exceeds 0.7 mm, the burr after molding is thick and post-finishing processing becomes difficult, and the reinforcing fiber may protrude from the slit 168. . Further, the slit may not be punched, but punching is preferable. This is because workability is improved by using a divided structure for cleaning the resin cured in the slit portion.

The position where the slit 168 is provided is preferably the following part. For example, as shown in FIG.
A state in which 64 is mounted on the molds (161, 162) is shown, but the lacking amount generally occurs at the portion called the 3 o'clock and 9 o'clock portions 169 and the joint portion with the yoke 170. Reference numeral 171 indicates the direction in which the pressurized medium is introduced. The deficiency occurs when air is trapped from the mating surface 166 at a location where resin flow is difficult. Therefore, as shown in FIG. 57, slits 168 are provided at the locations where air is trapped. Machining is performed by the wire electric discharge machining method, and a slit 168 having a width of 0.3 mm
As shown in FIG. 59, was provided all around the racket frame. As a result, the trapped air flowed to the outside of the mold through the slit 168 along with the resin flow, and the molding base material was completely adhered to the mold, and a racket frame made of fiber reinforced plastic with no gap was obtained.

[0171] In the method for manufacturing various FRP rackets described above, each part may be separately molded and joined to the frame molding base material.

For example, the yoke or grip of the racket may be separately molded or processed in advance and mounted in the cavity of the mold together with the molding base material so as to be integrated when molding the frame.

For example, the effect of preforming the grip portion will be examined. In the conventional molding method of the grip part, the grip is molded smaller than the required size when molding the frame, and in the post-processing step, the racket is set in the grip mold of the required size, polyurethane is poured, heated and foamed to make the grip. I was trying to get the shape. In this case, about 20 to 25 g of polyurethane is required to obtain a grip with the required hardness, which is a great obstacle in manufacturing an ultralight (ie, top heavy) racket.

In addition, in the conventional method, there is also a method called an integral molding method. That is, the grip part of the mold for molding the frame is preliminarily processed into a desired grip shape by the method used for manufacturing the ultralight racket, and the desired grip shape is obtained at the same time as the frame is molded. Although it can be made lighter than polyurethane foam, it also has the drawback that the impact of a ball is transmitted directly to the player. Further, since it has a hollow structure, bending rigidity and strength become problems when further weight reduction is intended. Moreover, it is necessary to prepare a mold for each grip size.

Therefore, as described above, the grip is molded or processed into a required shape in advance, and the grip is mounted in the cavity of the mold together with the molding base material and integrated with the frame.
The grip may be made of any material, but wood (strong in compression, easy to process, inexpensive, and good in shock absorption), especially balsa wood, can be used to reduce the weight.

For example, the inside of a grip, which has been molded or processed to a required size in advance, is hollowed out, and the one through which the molding base material forming the frame is passed through is attached to a mold, and heated and pressed (internal pressure). For example, the frame can be molded and the frame and the grip can be bonded at the same time. In this case, the grip may be integrated or may be divided into a plurality of parts.

[0177]

EXAMPLES Various specific examples of the present invention will be described below. Example 1, Comparative Example 1 First, regarding the racket frame having the configuration shown in FIG.
Carbon fiber is used as the reinforcing fiber 2, and the carbon fiber non-woven fabric layer 5
As the carbon fiber non-woven fabric constituting the above, a carbon fiber short fiber having a fiber diameter of 7 μm and a fiber length of 12 mm was processed by using the same resin as the matrix resin 3 constituting the fiber reinforced layer 4 as a fixing agent. Further, the carbon fiber nonwoven fabric 5 was impregnated with the same resin as the matrix resin 3 constituting the fiber reinforced layer 4 so that the fiber weight content rate was 30%. The basis weight of this non-woven fabric layer was 100 g / m ² . Further, the resin-impregnated carbon fiber non-woven fabric 5 is replaced with a nylon tube 1
In the outermost layer of the preform in which the prepreg impregnated with the reinforcing resin 2 and the matrix resin 3 is wound, further wound so as to occupy 60% of the total surface area of the racket frame, and after being assembled in the mold, it is placed in the tube. It was molded by applying pressure and heat curing.

As a result, it was possible to obtain excellent surface quality such that the putty filling step required in the conventional racket frame could be omitted. When the weight and the fiber volume content of the racket frame in the case where the carbon fiber nonwoven fabric layer is not provided (Comparative Example 1) are respectively 100, the racket according to the present invention has a weight of 89 and a fiber volume content of 113, which results in weight reduction. It was possible to realize high fiber volume content, that is, high strength. Since the putty filling step after molding can be omitted, cost can be reduced, and
Since the fiber volume content can be large, it was possible to efficiently provide a lightweight and high-strength racket frame.

Example 2 Five layers of a fiber-reinforced prepreg sheet impregnated with an epoxy resin, which was cut into a size of 38 mm width × 1750 mm length, were laminated, and the pressed laminate was used as a core material coated with a nylon tube (cross section: It was wound around a rectangular body (20 mm × 3 mm) to obtain a preform as shown in FIGS. Of the above five-layer stack, the contents of the outer layer bodies 12 and 13 are as shown in Table 1, and all the resins are epoxy resins. Among the reinforcing fibers used, the carbon fiber is manufactured by Toray Industries, Inc. ”
Trading card "T700S".

[0180]

[Table 1]

After decentering the preform having the above-mentioned structure, it was placed in the cavity of a frame-shaped mold of a tennis racket, and heated to about 150 ° C., and the nylon tube 14 (FIGS. 2 and 3) weighed about 8 kg. 20 tennis racket frames were molded by enclosing a compressed air of / cm ² and pressure molding. As shown in Table 2, a molded product having good surface quality with almost no voids and few resin flow failure parts was obtained.

Comparative Example 2 Using a preform in which the prepreg shown in Table 1 above was sequentially wound 10 times (2 times for each of 1 to 5 layers) in the conventional single layer unit shown in FIG. In the same manner, molding was performed using a mold to obtain 20 racket molded products.

The rackets formed in Examples 1 and 2 and Comparative Example 2 described above were evaluated for surface quality and strength one by one. As for the strength, the head crunch strength (the value of the load that causes a crack when a load is applied from the racket head), which is usually used as a strength evaluation scale for tennis rackets, was examined. The results are shown in Table 2.

Example 3 Next, a fiber-reinforced prepreg sheet impregnated with an epoxy resin was cut into 38 mm width × 1750 mm length, 5 layers were laminated, and the pressed laminate was used as a core material coated with a nylon tube. It was wound around (a rectangular body having a cross section of 20 mm × 3 mm) to obtain a preform as shown in FIG. Of the above five-layer stack, the contents of the outer layer bodies 23 and 24 are as shown in Table 1, and all the resins are epoxy resins. Among the reinforcing fibers used, the carbon fiber is manufactured by Toray Industries, Inc. ”
Torayca "T700S". In the racket frame having the structure shown in FIG. 9, the inner and outer layer bodies 2 are used as the reinforcing fiber layers.
In the same manner as in Example 1, carbon fiber short fibers having a fiber diameter of 7 μm and a fiber length of 12 mm were used as the carbon fiber non-woven fabric forming the carbon fiber non-woven fabric layer 5 using the above preforms composed of 3 and 24. The same resin as the matrix resin constituting the layers was used as a fixing agent and processed into a non-woven fabric.
Further, the same carbon resin as the matrix resin constituting the fiber reinforced layer is added to the carbon fiber nonwoven fabric 5 in a fiber weight content ratio of 30.
It was impregnated so that it became%. The basis weight of this non-woven fabric layer is 100 g
/ M ² . Further, the carbon fiber non-woven fabric 5 impregnated with the resin is applied to the outermost layer of the preform wound around the nylon tube 21 and the total surface area of the racket frame is 6
After further winding so as to occupy 0% and incorporating it in a mold, compressed air of about 8 kg / cm ² was enclosed in the tube and heat-cured to mold. Table 2 shows the results of forming 20 racket frames by the above method and evaluating the surface quality and strength. In Example 3, the surface quality and the strength were almost satisfactory, and the product was a good product.

[0185]

[Table 2]

As is clear from Table 2, in comparison with Comparative Example 2 according to the conventional method, Examples 1 to 3 according to the present invention have smaller variations in surface quality and strength, and no rejected products are produced. I understand.

Example 4 A prepreg sheet having the structure shown in Table 1 (width: 760 mm)
1 to 5 layers (length x 1800 mm) were laminated according to the construction order of Table 1, and the laminated body was pressed with a protective metal plate sandwiched (load: 100 ton).
After that, it was divided into 20 equal parts with a width of 38 mm by a cutting machine. The prepreg laminate after cutting was prepared into 10 racket preforms according to Example 2 described above, and was die-molded in the same manner as described above to produce 10 rackets. The surface quality and strength of the manufactured racket were evaluated in the same manner as in Example 2, and as a result, almost the same results as in Example in Table 2 were obtained.
Here, the time required from the lamination of the prepreg sheets to the cutting and the production of the racket preform was about 12 minutes for producing 10 pieces by two operators.

Comparative Example 3 Similarly, the prepreg sheet (width 76
1 mm to 5 layers (0 mm × length 1800 mm) were laminated according to the construction order of Table 1. However, double-sided release paper was placed between the layers so that the layers would not adhere to each other. After that, it was divided into 20 equal parts with a width of 38 mm by the procedure of Example 4. Each release paper was peeled off from the cut prepreg sheet, and ten racket preforms were prepared in the same manner as in Comparative Example 2. The time required during this period was about 2
It took 5 minutes. That is, compared with the conventional working method, the working method according to the present invention reduced the preform creation time to about 1/4.

Example 5 In Example 2 and Example 3, the overlapping portion (overlap region) of the inner laminate (inner prepreg sheet) and the outer laminate (outer prepreg sheet) was located at the gut hole position. When the gut tension was set to 40 kg, which is the high tension test value, no cracks were generated around the gut holes in all 20 of the gut holes. When the gut was provided at a place other than the overlapping portion, cracks occurred around the gut hole when 6 guts were put on the gut at a high tension test value of 40 kg. Thus, it can be seen that it is extremely effective to position the overlap region at the gut stretched portion.

As described above, by using a so-called two-piece preform, the preform easily moves smoothly to the surface of the mold during pressure molding, so that the surface quality and strength of the molded product are good, and These variations can be reduced. Further, the forming time of the preform by laminating the prepregs can be significantly shortened as compared with the conventional method. This is because the preform laminating process is simplified, and the mechanization (automation) of the preform manufacturing process can be easily performed.

Example 6 A 48-strand round braiding machine was used in triplet and a nylon thickness of 5 was used.
An airtight expansion tube of 0 μm and a folding width of 27 mm and two carbon fiber bundles (Toray Industries, Inc. Torayca T700S-12000) were placed on top of the carbon fiber bundles (Toray Industries, Ltd. Torayca T300-6).
000-50A) with all three layers braided at a braid angle of 30 °,
Immersed in epoxy resin liquid, impregnated with 40% by weight of prepreg resin and dried, then carbon fiber non-woven tape (Toray Industries, Inc., trading card T300, fiber length 12 mm, basis weight 30 g /
m ² , resin amount 50%, single-sided coating prepreg, tape width 25
(mm) was attached to both upper and lower surfaces by calender pressure and wound. The braided prepreg was set in a tennis racket mold, and air pressure of 8 kg / cm ² was applied to the inside of the tube to maintain the mold temperature at 150 ° C. for 20 minutes for molding. The braided prepreg has a nylon core airtight expansion tube and two carbon fiber bundles (Torayca T700S-12000) at the same time in the core, so there is no elongation of the braided structure and a braid width of 2
5 mm was held stably. Further, since a non-woven fabric having a resin applied only on one surface is attached to the surface, there is no tackiness and the workability is extremely good, and the molded product has a good quality with no appearance defect.

Example 7 A plurality of racket frames were manufactured by sequentially increasing the pressure applied to the flexible tube from 15 kg / cm ² · G by the molding method shown in FIG. 38, and the surface of the obtained frames was racketed. Visual observation was made in the vicinity of the yoke, which is one of the places where surface defects are most likely to occur in the hood.

[0193] As a result, there is no about 30kg / cm ² · surface unevenness observable size to the frame surface by the naked eye under a pressure of G, on the surface of the frame molded in 100 kg / cm ² · G, microvoids The results were excellent, and all of them were excellent in quality with no defects. In the manufacturing process, no turbine oil leaked from the flexible tube.

Comparative Example 4 On the other hand, for comparison, a compressed air of 25 kg / cm ² · G was used for the above-mentioned conventional method, and the vicinity of the yoke was visually observed by the above-mentioned method. The surface roughness was inferior and there were four large and small surface irregularities thought to be due to insufficient pressure contact pressure.

Example 8 Using exactly the same preform as in Example 3, 20 pieces were molded under the pressure of about 50 kg / cm ² · G in the same manner as in Example 7. As a result, the surface quality of all 20 pieces is the highest,
The strength of all 20 pieces was 180 to 200 kgf, and all were good products.

Example 9 The flexible tube shown in FIG. 39 was produced as follows.
A fluorosilicone rubber tube having an outer diameter of 13 mm, an inner diameter of 10 mm, a wall thickness of 1.5 mm and a hardness of 40 (JISA) is cut into a length of 1,800 mm, and the end portion has an outer diameter of 13 mm and an inner diameter of 5
A silicon tube of the same material having a length of 30 mm and a length of 30 mm was butted, and then unvulcanized fluorosilicon between both tubes was vulcanized in a mold to be integrated to form a thick portion. After being inserted into the joint 106, the outer tubular body 113 was so-called crimped to reduce the diameter of the outer tubular body 113 so that the crimping rate was 55%. In this embodiment, the joint 106 is a male-side joint of a commercially available one-touch coupler joint so that the joint 106 can be easily connected to the external pressure device. When the pressurized oil was supplied into the flexible tube by the external pressure device and the internal pressure was applied, 70 k
No oil leakage occurred up to g / cm ^2, and no oil leakage occurred even after repeated use.

Comparative Example 5 On the other hand, the outer diameter is 13 mm, the inner diameter is 10 mm, and the wall thickness is 1.5.
mm Fluorosilicone rubber tube (without thick part) is cut into a length of 1,800 mm, and one end is crimped at a rate of 4
Closing the other end after caulking 0%, was subjected to a increasing pressure leak test and sends an external pressurizing device temperature 0.99 ° C. of turbine oil # 32 inside the tube, the oil in 20 kg / cm ² A leak has occurred. Therefore,
When the caulking rate was 70%, the tube was cut.

Example 10 An FRP racket was manufactured by the RTM method as follows. A nylon tube is placed on a mandrel formed by focusing eight CFRP (carbon fiber reinforced plastic) wire rods having a thickness of 5 mm and a length of 2,000 mm, and a helical winding layer of carbon fiber is formed around the nylon tube using a filament winding method. After forming (inner layer: ± 15 ° layer × 3 layers, outer layer: 60 ° × 1 layer), the mandrel was pulled out to obtain a preform, which was used as a molding substrate.

Next, this molding substrate was placed in a split mold having a cavity in the shape of a racket frame which had been heated to near the molding temperature in advance, the upper mold was closed, and 1 kgf / cm ² was placed in a nylon tube. While introducing pressured air to pressurize the inside of the nylon tube and suction from the suction port provided in the upper mold to reduce the pressure to 50 Torr,
The resin preheated by a liquid mixing piston type resin injecting machine (manufactured by Naka Liquid Co., Ltd.) and the curing agent were mixed and injected at different injection speeds from the resin injection port (Table 3). When the resin reached the suction port, suction and injection were stopped, and the pressure inside the nylon tube was increased to 6 kgf / cm ² , and the injection port and the suction port were opened so that the excess resin would come out of the cavity. Leave it for 15 minutes to cure the resin, then remove from the mold.
After-curing treatment was performed at 0 ° C. for 2 hours to obtain a racket frame. As a result, a racket frame having a good surface property was obtained by optimizing the injection speed and injection pressure at the time of injecting the resin. The viscosity was measured by a B-type viscometer, and the Tg was measured by DSC in nitrogen at a temperature rising rate of 40 ° C./min.

[0200]

[Table 3]

Example 11 A fixed mandrel having a diameter of 16 mm and a length of 2,000 mm was covered with a nylon tube, and a carbon fiber bundle having a number of filaments of 6,000 was formed around the nylon tube.
Two layers of 8-stroke blades were stacked. Further, one layer of a braiding of 4,000 carbon fibers having 48 filaments was superposed thereon, and then the mandrel was pulled out to form a preform, which was used as a molding substrate.

Next, using Epocoat 827 (made by Yuka Shell Co., Ltd.) as a resin and Epicure 113 (made by Yuka Shell Co., Ltd.) as a curing agent (viscosity after mixing was 400 centipoise at 50 ° C.), Molding was performed under the same conditions as in Example 10 except that the injection temperature was 50 ° C. for 2 minutes. The surface of the obtained racket frame was good. Also, Tg is 132
It was ℃.

[0203]

As described in detail above, according to the bent pipe and the racket of the present invention, since the specific nonwoven fabric layer is arranged outside the reinforcing fiber layer, the flow of the resin is improved and the degassing property is improved during the molding. It is possible to obtain an FRP molded product having improved surface strength, no surface defects, and excellent strength characteristics.

Further, according to the method and apparatus for manufacturing the bent pipe and the racket made of FRP according to the present invention, it is possible to obtain the FRP molded product having the excellent surface characteristics and the excellent strength characteristics and the stable quality.

Furthermore, according to the preform and the method for producing the same according to the present invention, the FR of excellent quality as described above is used.
It becomes possible to efficiently and inexpensively manufacture a molding base material for obtaining a P-molded product.

[Brief description of drawings]

FIG. 1 is a partial perspective view of a bent pipe according to an embodiment of the present invention.

FIG. 2 is a sectional view of a preform according to an embodiment of the present invention.

FIG. 3 is a partial perspective view of the preform of FIG.

FIG. 4 is a partial perspective view of a racket preform according to an embodiment of the present invention.

FIG. 5 is a sectional view of a preform according to another embodiment of the present invention.

FIG. 6 is a perspective view showing a prepreg stack for producing a preform.

FIG. 7 is a perspective view showing cutting of a laminated prepreg.

FIG. 8 is a partial perspective view of a preform manufactured by using the prepreg of FIG.

9 is a cross-sectional view of a preform in which a nonwoven fabric layer is provided on the preform of FIG.

FIG. 10 is a schematic configuration diagram showing a method of manufacturing a preform according to an embodiment of the present invention.

11 is a schematic configuration diagram showing the next step of FIG.

FIG. 12 is a schematic configuration diagram showing the next step of FIG. 11.

FIG. 13 is a schematic configuration diagram showing a step subsequent to that in FIG.

FIG. 14 is a schematic configuration diagram showing a next step of FIG.

FIG. 15 is a schematic configuration diagram showing a step subsequent to that in FIG.

16 is a schematic configuration diagram showing a step subsequent to FIG.

FIG. 17 is a schematic configuration diagram showing a step subsequent to FIG. 16.

FIG. 18 is a schematic configuration diagram showing a step subsequent to that in FIG.

FIG. 19 is a schematic configuration diagram showing a step subsequent to FIG. 18.

20 is a schematic configuration diagram showing a step subsequent to FIG. 19.

FIG. 21 is a schematic configuration diagram showing a method of manufacturing a preform according to an embodiment of the present invention.

FIG. 22 is a cross-sectional view showing an example of a honeycomb body-embedded racket frame.

FIG. 23 is a cross-sectional view showing another example of the honeycomb body-embedded racket frame.

FIG. 24 is a cross-sectional view showing an example of a honeycomb body-buried yoke portion.

FIG. 25 is a cross-sectional view showing another example of the honeycomb body-buried yoke portion.

FIG. 26 is a perspective view showing a method of shaping a preform.

FIG. 27 is a schematic plan view of an automatic preform forming machine.

28 is a schematic plan view showing a step subsequent to FIG. 27. FIG.

29 is a schematic plan view showing a step subsequent to FIG. 28. FIG.

FIG. 30 is a schematic plan view showing the next step of FIG. 29.

31 is a schematic plan view showing a step subsequent to FIG. 30. FIG.

32 is a schematic plan view showing a step subsequent to FIG. 31. FIG.

FIG. 33 is a schematic configuration diagram of a tension holding mechanism portion of the automatic shaping machine in FIG. 27.

FIG. 34 is a schematic plan view of the vicinity of a yoke portion during shaping.

FIG. 35 is a perspective view of a molding substrate according to an example of the present invention.

36 is a partial cross-sectional side view of the flexible tube of FIG. 35.

37 is an enlarged cross-sectional view of a joint portion of the flexible tube of FIG. 35.

38 is a schematic configuration diagram when a racket is molded using the molding base material of FIG. 35.

FIG. 39 is a cross-sectional view of a flexible tube joint portion according to another example different from FIG. 37.

FIG. 40 is a schematic vertical sectional view of an FRP racket manufacturing apparatus according to an embodiment of the present invention.

41 is a plan view of the lower mold of the apparatus of FIG. 40. FIG.

42 is an enlarged sectional view around the resin injection port of the apparatus of FIG. 40.

43 is an enlarged cross-sectional view of a plug of a resin injection port and a pressure reduction port of the device of FIG. 40.

FIG. 44 is a front view showing an example of the mouth shape of the plug.

FIG. 45 is a front view showing another example of the mouth shape of the plug.

FIG. 46 is a front view showing still another example of the shape of the mouth of the plug.

FIG. 47 is a front view showing still another example of the shape of the mouth of the plug.

FIG. 48 is a front view showing still another example of the shape of the mouth of the plug.

FIG. 49 is a front view showing still another example of the shape of the mouth of the plug.

FIG. 50 is a front view showing still another example of the shape of the mouth of the plug.

51 is an enlarged cross-sectional view of the air supply port of the device of FIG. 40.

FIG. 52 is a cross-sectional view showing another example of the air supply port.

53 is an enlarged front view of the core portion of the apparatus of FIG. 40.

54 is a front view showing the next state of FIG. 53. FIG.

55 is a front view showing the next state of FIG. 54. FIG.

FIG. 56 is a partial vertical cross-sectional view of a mold showing a conventional molding state.

FIG. 57 is a partial vertical sectional view of a mold according to an embodiment of the present invention.

FIG. 58 is a perspective view showing racket frame molding.

59 is a plan view of the mold showing the slit disposition position in FIG. 57. FIG.

FIG. 60 is a partial perspective view of a conventional preform.

61 is a cross-sectional view of the preform of FIG. 60.

FIG. 62 is a partial cross-sectional view of a mold showing a conventional bent tube molding state.

FIG. 63 is a partial perspective view of a conventional bent tube having a surface defect.

FIG. 64 is a cross-sectional view of a conventional preform.

[Explanation of symbols]

1 tubular film 2 reinforcing fiber 3 matrix resin 4 reinforcing fiber layer 5 non-woven fabric layer 11, 12, 23, 24 prepreg 13, 22, 29 core material 14, 21, 28 tubular film 15, 25 preform 16 gut hole 26 prepreg 27 Laminated body 30 First prepreg 31 Opening 32 Second prepreg 41, 42, 43, 44, 45, 46 Press plate 47 Core material 48, 49 Prepreg 51, 52, 53 Braiding machine 54 Airtight expansion tube 55 Fiber Bundle 56 Multiple braid 57 Resin liquid 58, 61 Heating / drying device 59, 60, 62 Water cooling turn roll 63 Nonwoven fabric 64 Calendar device 65 Multiple braid prepreg 66 Tape-like fabric 71, 72 Frame 73, 74 Honeycomb body 75, 76 Yoke part 77, 78 Honeycomb body 79, 80 Gut 81 Cylindrical film 8 2 Reinforcing fiber sheet 83 Preform 84 Yoke 85 Convex part 86 type 91 Guide 92 Tension holding mechanism 93 Pressing roller 94 Cylinder 95 Grip part 96 Machine axis 97 Fixed roller 98 Moving roller 99 Air cylinder 100 Band brake 101 Flexible tube 102 Cylindrical Film 103 Prepreg 104 Molding base material 105 Turbine oil 106 Joint 107a Upper mold 107b Lower mold 108 Yoke part 109 Switching valve 110 Valve 111 Pressure gauge 112 Pressure hose 115 External pressurizing device 116 Tube tip 117, 118 Cylinder 119 Common rod 120, 121 Piston 122 Hydraulic pump 123 Piping 124 Connection part 125 Flexible tube 130 Mold 131 Upper mold 132 Lower mold 133 Resin injection port 134 Air supply port 135 Decompression port 36 cavity 137 sealant 138 gate 139 置中Ko 140 slide core 141, 142, the resin reservoir 143 plug 144 center line 145 shear plane 146,147,148,149,150,151,1
52 Plug mouth shape 153 Nozzle 154 Flange 155 Tapered portion 156 Molding base material 161 Upper mold 162 Lower mold 163 Cavity 164 Molding base material 165 Sliding core 166 Mating surface 167 Poor adhesion part 168 Slit 169 3 o'clock and 9 o'clock 170 Yoke 171 Pressurizing medium introduction direction

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁶ Identification code Office reference number FI technical display location B29C 70/10 B32B 1/08 Z 7415-4F 5/26 7421-4F C08J 5/24 7310-4F F16L 11/08 Z // B29K 105: 08 B29L 23:00 31:52 (72) Inventor Kazuhiko Nishimura 1-1-1, Sonoyama, Otsu City, Shiga Prefecture Toray Industries, Inc. Shiga Plant (72) Inventor Kosuke Yoshimura 1-1-1, Sonoyama, Otsu City, Shiga Prefecture, Toray Co., Ltd. Shiga Plant (72) Inventor Shinya Isoi 1-1-1, Sonoyama, Otsu City, Shiga Prefecture, Shiga Plant (72) Inventor Ohara Haruo 1515 Tsutsui, Matsumae-cho, Iyo-gun, Ehime Prefecture Toray Co., Ltd. Ehime Plant

Claims (53)

[Claims] 1. A reinforcing fiber layer is arranged on the inner side, and a single yarn diameter is 20 μm or less and a basis weight is 100 g on the outer side of the reinforcing fiber layer.
A bent pipe made of fiber reinforced plastic, characterized in that a non-woven fabric layer having a thickness of / m ² or less is arranged. 2. The bent tube of claim 1, wherein the layer of reinforcing fibers comprises a unidirectional aligner, fabric and / or braid of reinforcing fibers. 3. A reinforcing fiber layer in a range not exceeding 4 sets, each reinforcing fiber layer having a laminated constitution of a plurality of reinforcing fiber materials and having a C-shaped cross section, The bent pipe according to claim 1, wherein the opening portion of the lower reinforcing fiber layer is covered with the upper reinforcing fiber layer. 4. The bent pipe according to claim 1, wherein the fibers forming the non-woven fabric of the non-woven fabric layer are short fibers having a fiber length of 1 to 30 mm. 5. The bent pipe according to claim 1, wherein the non-woven fabric layer is arranged over the entire length in the length direction of the bent pipe. 6. The bent pipe according to claim 1, wherein the non-woven fabric layer is arranged over the entire circumference in the circumferential direction of the bent pipe. 7. A reinforcing fiber layer within a range not exceeding 4 sets, each reinforcing fiber layer having a laminated constitution of a plurality of reinforcing fiber materials and having a C-shaped cross section, A bent pipe characterized in that an opening portion of the lower reinforcing fiber layer is covered with the upper reinforcing fiber layer. 8. The bent pipe according to claim 7, wherein the reinforcing fiber material is a unidirectionally aligned body or a woven fabric of reinforcing fibers. 9. A reinforcing fiber layer in a range not exceeding 4 sets, each reinforcing fiber layer having a laminated constitution of a plurality of reinforcing fiber materials and having a C-shaped cross section, A preform for bending pipe molding made of fiber reinforced plastic, characterized in that the opening of the lower layer of reinforcing fiber is covered by the upper layer of reinforcing fiber. 10. The preform according to claim 9, wherein a non-woven fabric layer is arranged on the outside. 11. The preform according to claim 9, wherein the reinforcing fiber layer is prepregized. 12. A preform for bending pipe molding made of fiber reinforced plastic, comprising a braided layer made of reinforced fibers and a non-woven fabric layer arranged outside the braided layer. 13. The preform of claim 12, wherein the braided layer is prepregized. 14. The non-woven fabric of the non-woven fabric layer has a single yarn diameter of 20 μm or less and a basis weight of 100 g / m ^2.
The preform according to any one of claims 10 to 13, which is as follows. 15. A first reinforcing fiber sheet having a width at least shorter than the entire circumference of the tubular film is wound on the tubular film covered with the core material, and the first reinforcing fiber sheet Manufacture of a preform for bending pipe molding made of fiber reinforced plastic, characterized in that a second reinforcing fiber sheet is wound on the upper side so as to cover an opening of the wound first reinforcing fiber sheet. Method. 16. The first reinforcing fiber sheet and the second reinforcing fiber sheet
16. The method for manufacturing a preform according to claim 15, wherein the reinforcing fiber sheet of claim 1 has a laminated constitution of a plurality of reinforcing fiber materials. 17. The first reinforcing fiber sheet and the second reinforcing fiber sheet.
The reinforcing fiber sheet of claim 1 is prepregized.
5 or 16 preform manufacturing method. 18. A method for producing a preform for bending pipes made of fiber reinforced plastic, which comprises covering a tubular film with a braid of reinforcing fibers and winding a non-woven fabric on the braid. 19. The method for producing a preform according to claim 18, wherein the braid is prepregized. 20. A core material covered with a tubular film and a prepreg sheet of reinforcing fibers provided on the core material are held, and the prepreg sheet is pressed against the upper and lower surfaces of the core material along the outline of the core material. A pair of upper and lower first pressing means movable in the vertical direction, a prepreg sheet bent along the outer shape of the core material, and the folded prepreg sheet being pressed against the side surface of the core material; An apparatus for producing a preform for forming a bent pipe made of fiber reinforced plastic, comprising a pair of second pressing means. 21. A molding base material obtained by covering a flexible tube covered with a tubular film with a prepreg of reinforcing fibers is placed in a cavity of a mold, the mold is heated, and the inside of the flexible tube is 30 kg. / Cm ² · G or more and pressurize the above-mentioned molding base material to a metal mold, It is characterized by the above-mentioned. 22. A single yarn diameter is 20 μm on the prepreg.
The method for producing a bent pipe made of fiber-reinforced plastic according to claim 21, wherein a nonwoven fabric having a basis weight of 100 g / m ² or less is wound below. 23. A tubular film is coated with a prepreg of reinforcing fibers, and a single yarn diameter of 20 is provided on the prepreg.
A molding substrate formed by winding a non-woven fabric having a weight per unit area of 100 μm or less and having a weight of 100 g / m ² or less is placed in a cavity of a mold, and the mold is heated and the inside of the cylindrical film is pressed to mold the molding substrate. A method for producing a bent pipe made of fiber reinforced plastic, which comprises press-contacting a mold. 24. A molding base comprising a tubular film coated with reinforcing fibers, and a non-woven fabric having a single yarn diameter of 20 μm or less and a basis weight of 100 g / m ² or less is wound on the coating layer of the reinforcing fibers. The material is put in a cavity of a mold, the mold is heated, and the resin is injected into the cavity while pressurizing the inside of the tubular film and depressurizing the inside of the cavity. Pipe manufacturing method. 25. A mold having a cavity for accommodating a molding base formed by covering a tubular film covered with a flexible tube with a prepreg of reinforcing fibers, and an incompressible fluid in the flexible tube. And a pressurizing medium supply means for supplying a pressurizing medium of 30 kg / cm ² · G or more. 26. An upper and lower split mold having a cavity for accommodating a molding substrate formed by coating a tubular film with a prepreg of reinforcing fibers, and a pressurizing medium for supplying a pressurizing medium into the tubular film. An apparatus for manufacturing a bent pipe made of fiber reinforced plastic, comprising: a supply means; and a lower die including a core that is configured to be separable. 27. An upper and lower split mold having a cavity for accommodating a molding substrate formed by coating a tubular film with a reinforcing fiber, and a pressurizing medium supplying means for supplying a pressurizing medium into the tubular film. And a pressure reducing means for reducing the pressure in the cavity and a resin injecting means for injecting a resin into the cavity, and the lower die includes a core which is configured to be separable. An apparatus for manufacturing bent pipes made of fiber reinforced plastic, characterized by: 28. A fiber-reinforced plastic racket, wherein a reinforcing fiber layer is arranged on the inner side, and a nonwoven fabric layer having a single yarn diameter of 20 μm or less and a basis weight of 100 g / m ² or less is provided on the outer side of the reinforcing fiber layer. A racket characterized by being arranged. 29. The racket according to claim 28, wherein the reinforcing fibers constituting the reinforcing fiber layer are selected from carbon fibers, glass fibers and polyaramid fibers. 30. The racket of claim 28 or 29, wherein the layer of reinforcing fibers comprises unidirectional aligners, fabrics and / or braids of reinforcing fibers. 31. A reinforcing fiber layer in a range not exceeding 4 sets, each reinforcing fiber layer having a laminated constitution of a plurality of reinforcing fiber materials and having a C-shaped cross section, The racket according to any one of claims 28 to 30, wherein the opening portion of the lower reinforcing fiber layer is covered with the upper reinforcing fiber layer. 32. The racket according to claim 28, wherein the fibers forming the nonwoven fabric of the nonwoven fabric layer are selected from carbon fibers, glass fibers and polyaramid fibers. 33. The fiber constituting the non-woven fabric of the non-woven fabric layer is a short fiber having a fiber length of 1 to 30 mm.
The racket according to any one of 8 to 32. 34. The racket according to claim 28, wherein the non-woven fabric layer is arranged on a portion other than a grip of the racket. 35. The non-woven fabric layer is arranged in a portion other than the gut groove portion of the frame.
Racket described in any of. 36. The racket according to claim 28, wherein a wood or honeycomb body is at least partially arranged inside the reinforcing fiber layer of the frame and / or the yoke. 37. A racket according to any of claims 28 to 36, wherein the reinforcing fiber layer in the grip is covered with wood. 38. A reinforcing fiber layer within a range not exceeding 4 sets, each reinforcing fiber layer having a laminated constitution of a plurality of reinforcing fiber materials and having a C-shaped cross section, A preform for molding a racket made of fiber reinforced plastic, characterized in that an opening portion of the reinforcing fiber layer of the lower layer is covered with the reinforcing fiber layer of the upper layer. 39. The preform of claim 38, having a non-woven fabric layer disposed on the outside. 40. The preform of claim 38 or 39, wherein the reinforcing fiber layer is prepregized. 41. A racket-molding preform made of fiber reinforced plastic, comprising a braided layer made of reinforced fibers and a non-woven fabric layer arranged outside the braided layer. 42. The preform of claim 41, wherein the braided layer is prepregized. 43. The non-woven fabric of the non-woven fabric layer has a single yarn diameter of 20 μm or less and a basis weight of 100 g / m ^2.
The preform according to any one of claims 39 to 42, which is: 44. The preform according to claim 38, wherein a wood or honeycomb body is at least partially disposed inside the reinforcing fiber layer in a portion forming a frame and / or a yoke. . 45. A molding base material, which is obtained by covering a flexible tube covered with a tubular film with a prepreg of reinforcing fibers, is placed in a cavity of a mold, the mold is heated, and the inside of the flexible tube is 30 kg. / Cm ² · G or more and pressurize the above-mentioned molding base material to a metal mold, It is a manufacturing method of a fiber reinforced plastic racket. 46. A single yarn diameter is 20 μm on the prepreg.
The method for producing a fiber-reinforced plastic racket according to claim 45, wherein a nonwoven fabric having a basis weight of 100 g / m ² or less is wound below. 47. A tubular film is coated with a prepreg of reinforcing fibers, and a single yarn diameter of 20 is provided on the prepreg.
A molding substrate formed by winding a non-woven fabric having a weight per unit area of 100 μm or less and having a weight of 100 g / m ² or less is placed in a cavity of a mold, and the mold is heated and the inside of the cylindrical film is pressed to mold the molding substrate. A method for producing a fiber-reinforced plastic racket, which comprises press-contacting a mold. 48. A molding base comprising a tubular film coated with reinforcing fibers, and a non-woven fabric having a single yarn diameter of 20 μm or less and a basis weight of 100 g / m ² or less is wound on the coating layer of the reinforcing fibers. A racket made of fiber reinforced plastic, characterized in that the material is put into a cavity of a mold, the mold is heated, and the resin is injected into the cavity while pressurizing the tubular film and depressurizing the cavity. Manufacturing method. 49. The fiber-reinforced plastic racket according to claim 45, wherein the molding substrate is shaped by pressing it into a mold having the shape of the cavity before putting it into the cavity of the mold. Manufacturing method. 50. The method for producing a fiber-reinforced plastic racket according to claim 45, wherein a preformed yoke and / or a grip is put in a cavity of a mold together with the molding substrate. 51. A mold having a cavity for accommodating a molding base formed by covering a flexible tube covered with a tubular film with a prepreg of reinforcing fibers, and an incompressible fluid in the flexible tube. And a pressurizing medium supplying means for supplying a pressurizing medium of 30 kg / cm ² · G or more. 52. An upper and lower split mold having a cavity for accommodating a molding substrate formed by coating a tubular film with a prepreg of reinforcing fibers, and a pressurizing medium for supplying a pressurizing medium into the tubular film. An apparatus for manufacturing a racket made of fiber reinforced plastic, comprising: a supply means; and a lower die including a core that is configured to be separable. 53. A vertically-separated mold having a cavity for accommodating a molding substrate formed by coating a tubular film with reinforcing fibers, and a pressurizing medium supplying means for supplying a pressurizing medium into the tubular film. And a pressure reducing means for reducing the pressure in the cavity and a resin injecting means for injecting a resin into the cavity, and the lower die includes a core which is configured to be separable. An apparatus for manufacturing a fiber-reinforced plastic racket, which is characterized by: