JPH045973A - Racket frame - Google Patents

Abstract

PURPOSE:To improve mechanical characteristics, such as tenacity and to improve a repulsive fore, to prevent fracture and to increase a vibration damping characteristic by providing a hybrid prepreg layer between a central material and an outer shell forming material or on the outermost layer. CONSTITUTION:A cloth 5 is disposed on the 1st carbon fiber reinforced prepreg 4A which is held on release paper 10 and has carbon fibers specified in fiber diameter to 5 to 30mum as reinforcing fibers 2. The cloth 5 is so disposed at this time that the different fibers 6 woven into the cloth 5 and having 50 to 500mum fiber diameter larger than the fiber diameter of the carbon fibers are arranged in the same direction as the arranging direction of the carbon fibers 2 of the above-mentioned 1st carbon fiber reinforced prepreg 4A. Further, the 2nd carbon fiber reinforced prepreg 4B held on the release paper 10 similar to the 1st carbon fiber reinforced prepreg 4A is superposed on the above- mentioned prepreg in the form of crimping the cloth 5. The 1st carbon fiber reinforced prepreg 4A, the cloth 5 and the 2nd carbon fiber reinforced prepreg 4B are integrally joined, by which the hybrid prepreg 1 is formed.

Description

[Detailed Description of the Invention] Produced by JPY 1 The present invention relates to frames for various rackets, such as tennis rackets or badminton rackets, in which an outer molded material is provided around a center material, and in particular, A hybrid prepreg layer is provided between the material and the outer shell molding material and/or on the outermost layer, which is composed of fibers of a different type than the reinforcing fibers woven in a cloth (fabric) state. This relates to racket frames.

Niuraura Aimi: Traditionally, frames for tennis rackets, for example, were manufactured using the second
As shown in the figure, the core material 101 and the outer shell molding material 10
However, in recent years, carbon fiber or glass fiber has been used as the reinforcing fiber for the outer shell molding material 102 because it is lightweight, has high mechanical strength, and has good vibration damping characteristics. A fiber-reinforced composite resin material is used.

Such a conventional racket frame is produced by wrapping a predetermined number of fiber-reinforced prepregs to form an outer shell material 102 around a core material made of, for example, hard urethane foam, and curing the material. be done.

At this time, in order to improve the elastic modulus, torsional and bending performance, and furthermore to improve the vibration damping characteristics, a plurality of carbon fiber reinforced prepregs or a carbon fiber reinforced prepreg and a glass fiber reinforced prepreg are used. The outer shell molded material 102 is frequently constructed as a hybrid structure by overlapping the two.

However, in order to improve repulsive force, prevent breakage, and increase vibration damping properties, it is desired to improve mechanical properties such as tensile strength, compressive strength, elastic modulus, and stickiness. Further improvements are desired in terms of feel (hitting feel), moldability and aesthetics.

As a result of many research experiments, the present inventors found that in a racket frame in which an outer shell molding material is provided around a center material,
Between the core material and the outer shell molding material or as the outermost layer, and further between the core material and the outer shell molding material and as the outermost layer, the first
In other words, dissimilar fibers 6 having a fiber diameter of 50 to 500 μm are provided in the reinforcing fibers 2 having a fiber diameter of 5 to 30 ILm. It has been found that by providing a hybrid prepreg layer formed of hybrid prepregs 4 arranged in the same direction as the reinforcing fibers 2 at predetermined intervals, it is possible to provide a racket frame that can satisfy the above requirements.

Further, such a hybrid prepreg 4 is made of two unidirectional fiber-reinforced prepregs using reinforcing fibers 2 having a fiber diameter of 5 to 30 um, arranged at a predetermined interval in the same direction as the reinforcing fibers. Fiber diameter is 50-500um
It is manufactured by sandwiching and integrating different types of fibers 6, and in particular, it can be manufactured efficiently using a drum winder.

Lesson 1 Such hybrid prepregs can be produced relatively easily and can achieve improved mechanical strength and improved feel, but in some cases, during the manufacturing process or after manufacturing. In the process of shaping such a hybrid prepreg into a predetermined shape, it is experienced that the dissimilar fibers 6 arranged at a predetermined interval in the same direction as the reinforcing fibers become disordered in the arrangement direction. Disturbances in the arrangement of different types of fibers are not only undesirable from an aesthetic point of view, but also cause physical variations, which is also undesirable from a product quality point of view.

In order to avoid such fiber disturbances, extremely careful handling of dissimilar fibers during the manufacturing process or of hybrid prepregs after manufacturing is required, and handling performance (
There is a problem in terms of workability.

Therefore, an object of the present invention is to improve mechanical properties such as tensile strength, compressive strength, elastic modulus, and stickiness.
It is an object of the present invention to provide a racket frame that can improve repulsive force, prevent breakage, and increase vibration damping characteristics, and is also improved in terms of feel during use and moldability.

Another object of the present invention is to stabilize physical properties such as mechanical strength without disturbing the arrangement of the different fibers in a hybrid prepreg layer using reinforcing fibers with a small fiber diameter and different fibers with a large fiber diameter. To provide a racket frame that is easy to use, has excellent handling properties, and is also desirable from the aesthetic point of view.

The above-mentioned object for playing is achieved by the racket frame according to the present invention. In summary, the present invention provides a racket frame in which an outer molded material is provided around a center material, and the fiber diameter is 5 to 30 μm.
Among the reinforcing fibers with a fiber diameter of 50 to 500 μm
A hybrid prepreg layer having a cloth in which one or more types of different types of fibers are woven in the same direction as the reinforcing fibers at predetermined intervals is placed between the core material and the outer shell molding material. This racket frame is characterized in that it is provided between and/or on the outermost layer.

To explain further, the racket frame according to the present invention, as shown in FIG. It is made by winding a predetermined number of fiber-reinforced prepregs and curing them.

Furthermore, according to the present invention, the hybrid prepreg layer 1' is formed as the outermost layer of the outer shell molding material 102. Although not shown, the hybrid prepreg layer l° may be provided between the core material 101 and the outer shell molding material 102, or between the core material 101 and the outer shell molding material 102, and on the outermost M. You can also do it.

The core material 101 is preferably made of hard foamed urethane, and the outer shell material 102 is made of a plurality of carbon fiber reinforced prepregs or a combination of carbon fiber reinforced prepregs and glass fiber reinforced prepregs. By overlapping them, a hybrid structure can be created.

The carbon fiber-reinforced prepreg and glass fiber-reinforced prepreg used may be ordinary ones, and the reinforcing fibers used are carbon fibers (including graphite fibers) and glass fibers, and the matrix resins include epoxy resin and non-carbon fiber. Thermosetting matrix resins such as saturated polyester resins, polyurethane resins, diallyl phthalate resins, and phenolic resins can be used. Furthermore, the curing temperature is 50-2
A curing agent and other imparting agents, such as a flexibility imparting agent, are appropriately added so that the temperature is 00°C.

Next, the hybrid prepreg layer 1 which is a feature of the present invention
I will explain this in more detail.

FIG. 3 shows a hybrid prepreg 1 used to form a hybrid prepreg layer 1 according to the present invention.
An example of this is shown.

According to this embodiment, in a prepreg 4 having, for example, carbon fibers as reinforcing fibers 2 having a fiber diameter of 5 to 30 um, dissimilar fibers 6 having a fiber diameter of 50 to 500 LLm are placed in the same direction as the carbon fibers. are arranged at predetermined intervals. At this time, according to the present invention, the different types of fibers 6 are arranged in a state of being woven into the cloth.

That is, according to the present invention, as illustrated in FIG.
The different types of fibers 6 are woven using different types of fibers as warp threads and other fibers or the same fibers as the weft threads 8, and are positioned approximately at the center of the unidirectional carbon fiber prepreg 4 as a cloth (fabric) 5.

Note that the weft structure, fabric density, etc. of the cloth 5 are appropriately selected as necessary, but it is sufficient that the weft threads 8 are woven to the extent that the arrangement of different types of fibers, which are the warp threads 6, is fixed.

The hybrid prepreg 1 having such a structure can be produced by various methods, but in particular, the different fibers 6 are made of carbon fibers between two unidirectional carbon fiber reinforced prepregs using carbon fibers as reinforcing fibers. It is very suitably manufactured by arranging the cloths 5 in the same direction at predetermined intervals and integrating them by pressing and/or heating.

To explain further, as shown in FIG.
The fiber diameter is 5 to 30 μm as the reinforcing fiber 2 held in
The cloth 5 is placed on the first carbon fiber-reinforced prepreg 4A having carbon fibers, and at this time, the cloth 5 has a diameter of fibers woven into the cloth 5 compared to that of the carbon fibers. Dissimilar fibers 6 having a large fiber diameter of 50 to 500 μm are arranged so as to be arranged in the same direction as the arrangement direction of the carbon fibers 2 of the first carbon fiber reinforced prepreg 4A,
Furthermore, a second carbon fiber reinforced prepreg 4A held on release paper 10 similar to the first carbon fiber reinforced prepreg 4A is held in such a manner that the cloth 5 is sandwiched therebetween.
The carbon fiber-reinforced prepregs 4B of
Or by heating the first carbon fiber reinforced prepreg 4
A, the cloth 5 and the second carbon fiber reinforced prepreg 4B are joined together to form a hybrid prepreg l according to the present invention as illustrated in FIG.

The carbon fibers as the reinforcing fibers 2 of the first and second carbon fiber reinforced prepregs 4A and 4B may be the same carbon fiber (
, carbon fibers with different strengths can also be used.

Furthermore, different types of reinforcing fibers may be used for the prepreg 4A and the prepreg 4B.

The reinforcing fibers 2 are not limited to carbon fibers, but may also include inorganic fibers such as boron fibers with small fiber diameters, glass fibers, alumina fibers, silicon carbide fibers, and silicon nitride fibers; aramid fibers, polyethylene fibers, and polyethylene fibers. Organic fibers such as fibers; or metal fibers such as titanium fibers, amorphous fibers, and stainless steel fibers with small fiber diameters can be arbitrarily used. The reinforcing fiber 2 has a fiber diameter of 5 to 30 μm, preferably 6 to 12 μm.

As the different fibers 6, inorganic fibers such as boron fibers, which have a larger fiber diameter than the reinforcing fibers 2, and metal fibers such as titanium fibers, amorphous fibers, and stainless steel fibers are preferably used. is 50~150μ
m, preferably 70 to 120 μm.

Furthermore, according to the present invention, glass fiber,
Inorganic fibers such as alumina fibers, silicon carbide fibers, and silicon nitride fibers; organic fibers such as aramid fibers, polyarylate fibers, and polyethylene fibers can also be used. However, these fibers generally have a small fiber diameter, that is, a monofilament diameter (d) of 5 to 50 μm. It is used in the form of a strand (fiber bundle) 6, which is made by bundling a large number of fibers 6a together.

Therefore, it is also possible to use metal fibers with small fiber diameters in the form of strands.

Different types of fibers 6 in the form of such strands
In this specification, the fiber diameter is the converted diameter expressed by the following formula. shall mean.

D o = FW-d n: Number of convergent strands d: Fiber diameter Also, when such a strand is used as the dissimilar fiber 6, regardless of whether it is twisted or not, as shown in Fig. 7,
Converted diameter in hybrid prepreg 1. It does not exist in the form of a circular cross section, but is usually deformed into a flattened state. Therefore, as described above, it is necessary to manufacture a hybrid prepreg l having the same thickness (T) as when using boron fibers, titanium fibers, amorphous fibers, stainless steel fibers, etc. with large fiber diameters as the different fibers 6. The strands are made of different fibers6
Fiber diameter when used as , equivalent diameter. is preferably set to a maximum of 500 μm.

For example, for organic fibers such as polyarylate fibers whose fiber diameter d is 23 μm, the equivalent diameter is obtained by converging 300 fibers. is 398 μm, and the fiber diameter d is 13 μm.
By converging 800 glass fibers, the converted diameter D0 is 368 μm, and both of these strands are also suitably used as the different fibers 6 to produce a hybrid prepreg 1 as shown in FIG. can do.

The weft threads 8 constituting the cloth 5 can be the same as the different fibers 6 or the reinforcing fibers 2, and furthermore, various other fibers can be used.
Generally, it is preferable to use inorganic fibers such as glass fibers and alumina fibers, and organic fibers such as polyethylene fibers and polyester fibers. As the weft, thin fibers or thin fiber bundles, and transparent ones are more preferable. From this point of view, glass fibers, polyethylene fibers, alumina fibers, etc. are particularly preferred.

As the matrix resin, thermosetting matrix resins such as epoxy resin, unsaturated polyester resin, polyurethane resin, diallyl phthalate resin, and phenol resin can be used. Furthermore, a curing agent and other imparting agents, such as a flexibility imparting agent, are appropriately added so that the curing temperature is 50 to 200°C.

To give a preferred example, epoxy resin is preferred as the matrix resin, and usable epoxy resins include (1) glycidyl ether epoxy resin (
Bisphenol A, F.

S-based epoxy resin, novolac-based epoxy resin, brominated bisphenol A-based epoxy resin); (2) cycloaliphatic epoxy resin; (3) glycidyl ester-based epoxy resin; (4) glycidylamine-based epoxy resin (tetraglycidyl diamino diphenylmethane, triglycidyl-p-aminophenol, etc.); (5) heterocyclic epoxy resin; one or more selected from various other epoxy resins are used; in particular, bisphenol A
, F, S glycidylamine-based epoxy resins are preferably used. In addition, as a curing agent, an amine type curing agent such as dicyandiamide (DICY), diaminophenyl sulfone (DDS), diaminodiphenylmethane (DDM) is used.
; acid anhydride systems, such as hexahydrophthalic anhydride (HH
PA), methylhexahydrophthalic anhydride (MHHP)
A), etc. are used, and amine-based curing agents are particularly preferably used.

Further, the blending ratio of reinforcing fibers, different types of fibers, and matrix resin in the hybrid of the present invention can be adjusted arbitrarily, but generally, in weight%, reinforcing fibers: different types of fibers: matrix resin = (40 to 80): (2 to 80) 20): (20~6
0). Further, according to the present invention, the thickness (T) of the prepreg can be made to be approximately the same as the fiber diameter of the different types of fibers used, but it will usually be about 80 to 200 μm.

In the above embodiment, the explanation has been made on the assumption that there is only one type of different type of fiber 6, but the present invention is not limited to this, and can include two or more types of different type of fiber. For example, in FIGS. 8 and 9, two types of fibers 6 are shown in the cloth 5 as different types of fibers.
This shows an embodiment in which a and 6b are woven. In this example, 2
Although the seed fibers 6a and 6b are woven alternately, the arrangement is not limited to this, and any arrangement is possible.

The manufacturing method of the above embodiment will be described in more detail with numerical values as follows.

The first and second carbon fiber reinforced prepregs 4A and 4B using carbon fiber as reinforcing fibers have the same configuration,
It was formed with a thickness of 65 μm on a release paper 10 with a thickness of 120 μm. The carbon fibers used as the reinforcing fibers 2 were PAN-based carbon fibers (manufactured by Toshi Co., Ltd., trade name: rM40J) with a fiber diameter of 6.5 μm, and the matrix resin was an epoxy resin. Further, the content of matrix resin in the prepreg was 35% by weight.

As the different fibers 6, boron fibers and titanium fibers were used, and as the weft threads 8, glass fibers having a fineness of 1Og/1000m were used.

Boron fibers have a fiber diameter of 100μm and are 1mm.
The cloth 5 was prepared by weaving the weft threads 8 at intervals of 05 mm.

In addition, titanium fibers with a fiber diameter of 100 μm are
The cloth 5 was prepared by arranging the fabrics at intervals of 0.5 mm and weaving the weft threads 8 at intervals of 0.5 mm.

The first and second carbon fiber-reinforced prepregs 4A and 4B are pressed toward each other using a press roll (not shown) heated to 100°C and heated and pressurized to form the first carbon fiber-reinforced prepreg 4A and the cloth. 5 and second carbon fiber reinforced prepreg 4B
were joined together. As a result, a hybrid prepreg 1 according to the present invention as shown in FIG. 3 was formed.

The mechanical strength and other properties of the hybrid prepreg manufactured in this way were measured, and although the hybrid prepreg used in the present invention is thin, both the compressive strength and elastic modulus are as shown in Figure 1O. It showed physical properties equivalent to prepreg.

Furthermore, in the hybrid prepreg used in the present invention, the different fibers 6 can be easily aligned in parallel with the reinforcing fibers 2 during the manufacturing process, and the prepreg 1 manufactured in this way can be used. Even when molding a racket frame, the arrangement of the different types of fibers 6 was not disturbed in the length direction of the fibers (this was easy to work with and aesthetically pleasing).

In the above embodiment, the first and second w & fiber reinforced prepreg 4
Both A and 4B were carbon fiber reinforced prepregs using carbon fibers as reinforcing fibers, but the first fiber reinforced prepreg 4A used carbon fiber reinforced prepregs using carbon fibers as reinforcing fibers, and the second fiber reinforced prepreg used carbon fiber reinforced prepregs. Prepreg 4
As B, a glass fiber reinforced prepreg using glass fiber as the reinforcing fiber was used, and a hybrid prepreg was produced in the same manner as described above.

In this example, the first carbon fiber reinforced prepreg 4A is
Similar to the above example, it is formed with a thickness of 65 μm on a release paper 10 with a thickness of 120 μm, and reinforcing fibers 2
The carbon fiber is PA with a fiber diameter of 6.5 μm.
N-based carbon fiber (manufactured by Toshi Co., Ltd.: product name rM40J)
It was used.

Further, the second glass fiber reinforced prepreg 4B has a fiber diameter of 13
Micrometer glass fiber was used, and epoxy resin was used as the matrix resin. Further, the content of matrix resin in the prepreg was 35% by weight.

As the different fibers 6, boron fibers and titanium fibers were used, and as the weft threads 8, glass fibers with a fineness of 10 g/1000 m were used.

Boron fibers have a fiber diameter of 100μm and are 1mm.
The cloth 5 was prepared by inserting the weft threads 8 at intervals of 05 mm and 5 mm.

In addition, titanium fibers with a fiber diameter of 100 μm are
The cloth 5 was prepared by arranging the fabrics at intervals of 0.5 mm and weaving the weft threads 8 at intervals of 0.5 mm.

The hybrid prepreg according to this example can exhibit the above-mentioned effects similar to those of the previous example, and also has a second
Since the fiber-reinforced prepreg is glass fiber-reinforced prepreg and furthermore, glass fiber is used as the weft thread 8 of the cloth, the second fiber-reinforced prepreg side is transparent, and therefore there are no disordered (aligned dissimilar fibers) inside the hybrid. It became possible to observe the image from the outside, and it was also aesthetically superior.

Furthermore, using the above hybrid prepreg 1, the first
A frame for a tennis racket as shown in the figure was manufactured.

The mechanical properties of the racket frame were measured, and although the racket frame according to the present invention is lightweight, it has poor tensile strength, compressive strength, elastic modulus, and impact resistance.
It is superior to the conventional racket frame shown in Figure 2,
The feel during use was good, and the repulsion and vibration damping properties were also improved.

Further, a hybrid prepreg as shown in the second embodiment according to the present invention, that is, a hybrid prepreg in which the second fiber-reinforced prepreg is a glass fiber-reinforced prepreg and furthermore, glass fiber is used as the weft thread 8 of the cloth When the prepreg was provided as the outermost layer, the different types of fibers were arranged without disorder in the length direction of the fibers, which was also aesthetically pleasing.

In the description of each of the above embodiments, the cloth 5 disposed in the hybrid prepreg 4 has a structure in which different types of fibers 6 are used as warp yarns, but the cloth 5 used in the present invention
(For example, as shown in FIG. 10, fixing fibers 9 can be further arranged and woven between the different types of hem fibers 6 as warp yarns.)

The fixing warp 9 used for this purpose can be the same as the weft 8, and as described above, can also be the same as the reinforcing fiber 2 in the hybrid prepreg 4, and furthermore, Although various other fibers can be used, usually inorganic fibers such as glass fibers and alumina fibers,
It is preferable to use organic fibers such as polyethylene fibers and polyester fibers. Also as a fixing warp 9,
Thin fibers or thin fiber bundles, and transparent ones are more preferable. From this point, like the weft thread 8, especially glass fiber,
Polyethylene fibers, alumina fibers, etc. are preferred.

More specifically, in each of the above embodiments, glass fibers with a fineness of 10 g/1000 m are used as the weft yarn 8 and the fixing warp yarn 9, and different types of fibers 6 such as boron fibers and titanium fibers are arranged at 2 mm intervals. Then, three fixing warp yarns 9 are arranged between each of the different types of fibers 60 at intervals of 0.5 mm, and weft yarns 8 are arranged at intervals of 0.5 mm, and are woven as shown in FIG. 10 to produce the cloth 5. did.

A frame for a tennis racket was manufactured using the cloth 5 produced using the fixing warp 9 in this way, and the different types of fibers 6 could be fixed at a predetermined pitch.
It was possible to almost completely eliminate the disorder in the fiber orientation.

Anal support 1 The racket frame according to the present invention configured as described above can improve mechanical properties such as tensile strength, compressive strength, elastic modulus, and stickiness, and can improve repulsive force. It is possible to improve the performance, prevent breakage, and increase vibration damping properties, and is also excellent in terms of feel during use and moldability. Furthermore, the racket frame of the present invention has the following features:
In a hybrid prepreg layer that uses reinforcing fibers with a small fiber diameter and dissimilar fibers with a large fiber diameter, the arrangement of the dissimilar fibers is not disordered, and physical properties such as mechanical strength can be stabilized, resulting in improved handling properties. It is excellent and also preferred from the aesthetic point of view.

[Brief explanation of drawings]

FIG. 1 is a cross-sectional view of a racket frame according to the present invention. FIG. 2 is a cross-sectional view of a conventional racket frame. FIG. 3 is a cross-sectional view of an embodiment of a hybrid prepreg for manufacturing a racket frame according to the present invention. FIG. 4 is a perspective view showing an example of a cloth woven with different types of fibers used in the present invention. FIG. 5 is a diagram for explaining one embodiment of a method for manufacturing a hybrid prepreg. FIG. 6 is a diagram for explaining the converted diameter when the fiber diameter is small. FIG. 7 is a cross-sectional view of a hybrid prepreg using fibers with a small fiber diameter. FIG. 8 is a sectional view of another embodiment of a hybrid prepreg for manufacturing according to the present invention. FIG. 9 is a perspective view showing an example of a cloth woven with different types of fibers used in the hybrid prepreg of FIG. 8. FIG. 1O is a perspective view showing another example of a cloth woven with different types of fibers used in the hybrid prepreg according to the present invention. FIG. 11 is a cross-sectional view for explaining an example of a conventional hybrid prepreg. 1°; Hybrid prepreg layer 101; Core material 102: Outer shell molding material 1; Hybrid prepreg 2: Reinforcing fiber 5: Cloth 6: Different type of fiber (warp) 9: Fixing warp 8: Weft

Claims (1)

[Claims] 1) In a racket frame in which an outer shell molding material is provided around a core material, one or more types of different fibers having a fiber diameter of 50 to 500 μm are added to the reinforcing fibers having a fiber diameter of 5 to 30 μm. A hybrid prepreg layer having a cloth woven in the same direction as the reinforcing fibers at predetermined intervals is provided between the core material and the outer shell molding material and/or as the outermost layer. A racket frame featuring