JP2006051063A - Wooden bat - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a wooden bat with practically sufficient durability/strength as a bat and excellent restitutive performance, capable of exhibiting excellent hitting feel. <P>SOLUTION: Epoxy resin whose viscosity is 50 cps is prepared as synthetic resin 4, and carbon nano-fiber with such properties that the mean fiber diameter is 150 nm, the mean fiber length is 15 μm, the aspect ratio (the mean fiber length/the mean fiber diameter) is 100, the specific surface area is 13 m<SP>2</SP>/g, and the heat conductivity at the temperature of 15 °C is 1500 W/(mK), is mixed in the synthetic resin as micro-carbon fiber 5 at a rate of 1 mass % to obtain a synthetic resin material. The obtained synthetic resin material is impregnated into a hitting area of a wooden bat body 2, and after that, the impregnated part is compression-molded to form the wooden bat. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a wooden bat used in ball games such as baseball and softball.

  Conventionally, blue damwood, ash, yachidamo and the like have been used as wooden bats. In general, blue duck and ash can be used as white wood, but recently these wood resources are depleted, making it difficult to obtain them, resulting in an imbalance between supply and demand. On the other hand, Yachidamo wood is abundant in resources, but due to the nature of Yachidamo wood itself, the diameter of the conduit in the wood pores is large, and the number of conduits is several. For example, repeated hitting has a problem that splitting or peeling occurs in the conduit portion.

  Therefore, conventionally, in order to solve such a problem, resin injection forcibly injecting a synthetic resin such as phenol resin, epoxy resin or unsaturated polyester resin into the cells of the wood part and conduit part of the wooden bat So-called compression bats, which are compressed with a bat or a mold after injection of the synthetic resin and heated and cured, have been proposed and put into practical use.

  By the way, in such a resin injection bat or compression bat, the degree of dependence on the durability strength is high in the synthetic resin to be used, and in order to express more excellent strength and durability, In some cases, reinforcing materials may be added. As a reinforcing material to be added and mixed in such a synthetic resin, for example, as proposed in Patent Document 1, whisker materials such as silicon carbide whisker and silicon nitride whisker are generally used.

JP-A 63-281670

  According to the bat having such a configuration, the wood portion of the bat and the synthetic resin injected into the conduit portion are reinforced and strengthened by the whisker material, so that it is more durable than the bat formed without adding the whisker material. The strength could be improved to some extent.

  However, the whisker material that has been generally used in this way has a characteristic of low thermal conductivity and poor heat dissipation. For example, as a typical example, the thermal conductivity of silicon nitride whisker is 20 to 30 W / (m · K) under the condition of 5 to 30 ° C. (temperature at which the bat is actually used). 1.2 to 1.4 W / (m · K) is low, and when these resin injection batts or compression bats are formed by adding and mixing these whisker materials into the synthetic resin, the thermal conductivity of the bat itself The vibration that occurs when the ball is hit is less likely to be consumed as thermal energy. As a result, the vibration attenuation of the bat is inferior, the soft feeling inherent in the wood is lost, and it is difficult to obtain a good shot feeling.

  In addition, the whisker material is usually a rigid crystal, and when added to a synthetic resin, the toughness of the resin to be cured and molded becomes poor and the impact strength is inferior, and the elasticity of the resin is low. Since it becomes poor, it is predicted that the resilience performance of the bat will be greatly reduced. Further, as a result of a hit test conducted by the present inventor, it has been found that when this type of bat is repeatedly hit, the bat splits along the grain, particularly in the hitting ball region. This is because the synthetic resin filled in the conduit portion of the wooden bat body is rigidized by the whisker material, so that the rigidized conduit portion exerts a so-called wedge action when hitting the ball, and the bat follows the grain. It is presumed that it becomes easy to split.

  Therefore, in view of such conventional problems, the present invention provides a wooden bat that has a practically sufficient durability as a bat, has excellent resilience performance, and can exhibit a good shot feeling. It is the purpose.

In order to achieve the above object, the present invention is configured as follows.
That is, the wooden bat according to claim 1 of the present invention is a wooden bat in which at least a part of the wooden bat main body is reinforced with a synthetic resin. It is a crystal material having a layer structure or a multilayer structure and having a fine hollow part in the center part, and that fine carbon fibers whose average fiber diameter is set within a range of 10 to 300 nm are mixed. It is a feature.

  Moreover, Claim 2 is the wooden bat according to Claim 1, wherein the viscosity of the synthetic resin at normal temperature is set in a range of 10 to 500 cps, and the fine carbon fiber is 0 in the synthetic resin. It is mixed at a ratio of 1 mass% or more and 10 mass% or less.

  A third aspect of the present invention is the wooden bat according to the first or second aspect, wherein the hitting portion of the wooden bat main body is reinforced with a synthetic resin mixed with the fine carbon fibers. is there.

  A fourth aspect of the present invention is the wooden bat according to the first, second, or third aspect, wherein the wooden bat is a resin-injected bat in which the synthetic resin mixed with the fine carbon fibers is injected and cured into a wooden bat body. It is characterized by this.

  Claim 5 is the wooden bat according to claim 1, 2, or 3, wherein the wooden bat is compression-cured after injecting and impregnating the wooden bat body with the synthetic resin mixed with the fine carbon fiber. It is characterized by being a bat.

  As described above, in the present invention, in a wooden bat in which at least a part of the wooden bat main body is reinforced with a synthetic resin, a single layer structure in which crystals of a carbon hexagonal mesh surface are wound in a cylindrical shape in the synthetic resin, or It is a crystal material that has a multilayer structure and has a fine hollow part at the center, and a fine carbon fiber whose average fiber diameter is set within a range of 10 to 300 nm is mixed, so that the wooden bat body Since the synthetic resin filled in the wood part or the conduit part can be effectively reinforced, the shear strength can be remarkably improved. As a result, the strength and durability can be remarkably improved.

  The fine carbon fiber has a very high thermal conductivity, and can increase the thermal conductivity of the wooden bat itself. As a result, the vibration that occurs in the wooden bat at the time of hitting the ball is quickly consumed as thermal energy, so the vibration damping is increased and the soft and good nature of the tree is good even though it is a bat reinforced with synthetic resin. A feel at impact can be obtained.

  Furthermore, since the fine carbon fiber has excellent resilience characteristics and gives appropriate elasticity to the synthetic resin to be cured and molded, the resilience performance of the wooden bat itself can be greatly improved. Further, since the cured synthetic resin has an appropriate elasticity, the conduit portion of the bat body does not become rigid. Therefore, there is no problem that the conduit portion has a wedge action when the ball is hit, and the grain is not easily split even when repeated hitting.

Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the drawings.
FIG. 1 shows an external view of a wooden bat 1 according to the present embodiment, and FIG. 2 shows an explanatory diagram of a main part configuration in a region A of FIG.

  That is, the wooden bat 1 of this embodiment is a ball hitting the wooden bat main body 2 formed by cutting a wood such as a blue damwood material, an ash material, a yachidamo material into a bat shape as shown in FIGS. The portion 3 region is reinforced with the synthetic resin 4. In such a wooden bat 1, the synthetic resin 4 is injected and impregnated into the striking ball 3 region of the wooden bat main body 2, and then compression-molded, so that the synthetic resin 4 is impregnated and cured in the wood portion and the conduit portion. The impregnation part is constituted.

  And in the wooden bat 1 of a present Example, the fine carbon fiber 5 demonstrated below is mixed in the synthetic resin 4 which forms the above-mentioned resin impregnation part as a reinforced material.

  The fine carbon fiber 5 is generated by a method such as a vapor deposition method, an arc discharge method, a laser ablation method, a plasma synthesis method, and the like, and a single layer structure in which a crystal of a carbon hexagonal mesh surface is wound in a cylindrical shape or a multilayer structure It is a crystalline material having a structure and a fine hollow portion at the center thereof, and is made of a very fine carbon fiber material having a fiber diameter of nanometer order. As such fine carbon fibers 5, carbon nanotubes or carbon nanofibers are used.

  This type of fine carbon fiber 5 is a fine fiber that is lightweight and excellent in specific strength. When this is mixed into the synthetic resin 4, the fine carbon fiber 5 serves as a filler that reinforces the synthetic resin 4. Play a role. In particular, since the synthetic resin 4 filled in the wood portion or the conduit portion of the wooden bat body 2 can be effectively reinforced, the shear strength can be remarkably improved, and as a result, a particularly excellent strength and durability can be expressed. it can.

  The fine carbon fiber 5 has an extremely high thermal conductivity compared to other known materials, and can increase the thermal conductivity of the wooden bat 1 itself. As a result, the vibration generated in the wooden bat 1 at the time of hitting the ball is quickly consumed as thermal energy, so that the vibration damping is improved and the original wood has the wooden bat 1 reinforced with the synthetic resin 4. It is possible to obtain a soft and good shot feeling.

  Furthermore, since the fine carbon fiber 5 has excellent resilience characteristics and gives appropriate elasticity to the synthetic resin 4 to be cured and molded, the resilience performance of the wooden bat 1 itself can be greatly improved. This is presumed to be because the fine carbon fiber 5 has a crystal structure having a fine hollow portion at the center thereof. Further, since the cured synthetic resin 4 has an appropriate elasticity, the conduit portion of the wooden bat main body 2 does not become rigid. As a result, the conduit portion does not exhibit a wedge action when the ball is hit, and the grain does not easily split even when hit repeatedly.

  The fine carbon fiber 5 has a tendency that the smaller the fiber diameter, the better the reinforcing effect and the higher the thermal conductivity. Moreover, the larger the hole diameter of the hollow part, the better the resilience performance and the higher the impact strength. In this embodiment, the average fiber diameter is set within the range of 10 to 300 nm, particularly within the range of 20 to 200 nm, and the average fiber length is 2 to 30 μm, as suitable for reinforcing the wooden bat body 2. In particular, those in the range of 5 to 20 μm are used. The thermal conductivity is within a range of 1000 to 3000 W / (m · K), particularly 1500 to 2000 W / (m · K) under the condition of 5 to 30 ° C. (temperature at which the bat is actually used). Those within the range are used. Furthermore, the pore diameter of the hollow portion is preferably within the range of 10 to 60% of the average fiber diameter, particularly 30 to 50%.

  In the above, the upper limit value of the average fiber diameter of the fine carbon fibers 5 is set to 300 nm because when the fiber diameter is larger than this, the fine carbon fibers are placed inside the woody part of the wooden vat body 2 or the conduit part. 5 cannot efficiently enter, the reinforcing effect of the synthetic resin 4 impregnated in the wooden bat body 2 cannot be sufficiently exhibited, and satisfactory strength and durability performance as the wooden bat 1 cannot be obtained. This is because the thermal conductivity becomes low and good vibration damping cannot be expressed. Also, the lower limit is set to 10 nm because when the fiber diameter is smaller than this, the handling becomes difficult, and it cannot be contained uniformly in the synthetic resin 4 and the quality of the wooden bat 1 is improved. This is because variations may occur.

  In addition, the upper limit of the average fiber length is set to 30 μm because when the average fiber length is larger than this, the fine carbon fibers 5 efficiently enter the wood portion or the conduit portion of the wooden bat body 2. The lower limit is set to 2 μm because the handling becomes difficult when the average fiber length is smaller than this.

  The upper limit value of the thermal conductivity is set to 3000 W / (m · K). In the fine carbon fiber 5 that can be known at present, this value is the upper limit value that can be obtained within the setting range of the average fiber diameter. This is because the lower limit is set to 1000 W / (m · K). If the thermal conductivity is smaller than this, the vibration damping property of the wooden bat 1 is inferior, and a good shot feeling is exhibited. Because it becomes impossible.

  In addition, the upper limit value of the hole diameter of the hollow portion is set to 60% of the average fiber diameter as described above, so that it can be produced while ensuring good quality among the fine carbon fibers 5 that can be known at present. This is because the upper limit value that can be obtained is this value, and the lower limit value is set to 10% because if it is smaller than this value, it will be difficult to develop good resilience performance and impact strength.

Further, the fine carbon fiber 5 is 0.1% by mass or more and 10% by mass or less, particularly 3% by mass or more and 7% by mass in the synthetic resin 4 whose viscosity at normal temperature is set within a range of 10 to 500 cps. It is preferable to mix in the following ratio.
If the amount of the fine carbon fiber 5 used is less than 0.1% by mass, the reinforcing effect of the synthetic resin 4 cannot be sufficiently exhibited, and satisfactory strength and durability performance as the wooden bat 1 cannot be obtained. At the same time, vibration damping and resilience performance cannot be sufficiently improved. Further, if the amount is more than 10% by mass, there is a problem that it is difficult to mix evenly in the synthetic resin 4, and the wooden bat is used even if the fine carbon fiber 5 is used more than 10% by mass. No good evaluation was obtained in the durability, vibration damping property, resilience property, and the like.

  Moreover, when the fine carbon fiber 5 is mixed in the synthetic resin 4, the amount of the synthetic resin 4 impregnated in the wooden bat main body 2 flowing out can be suppressed. That is, since the flow control of the resin can be performed, the bat can be formed using the synthetic resin 4 having a relatively low viscosity such as 10 to 500 cps, which has excellent permeability to the wood part and the conduit part of the wooden bat body 2. This enhances the resin impregnation into the wooden bat body 2 and further suppresses resin outflow during molding, so that voids and pinholes are unlikely to form on the molded bat surface, requiring reworking in a later process. A wooden bat 1 having excellent molding quality can be obtained. As a result of various experiments, when the viscosity of the synthetic resin 4 is higher than 500 cps, it is difficult to impregnate the synthetic resin 4 into the woody portion and the inside of the conduit portion of the wooden bat main body 2, and it is difficult to obtain sufficient design strength. In addition, if it is lower than 10 cps, it is difficult to sufficiently control the flow, so that a large amount of the synthetic resin 4 flows out, and reworking is necessary in a post-process after molding. The viscosity of the synthetic resin 4 is particularly preferably 30 to 70 cps. Examples of the synthetic resin 4 that can be used include an epoxy resin, a phenol resin, a nylon resin, and an unsaturated polyester resin. An epoxy resin is preferable in terms of strength, durability, and moldability. .

Still further, the surface state of the fine carbon fiber 5 varies depending on the generation temperature. In the present embodiment, in consideration of wettability with the synthetic resin 4, those having a specific surface area in the range of 11 to 15 m ² / g are preferably used.
When the specific surface area is larger than 15 m ² / g, there arises a problem that it is difficult to uniformly mix in the synthetic resin 4, and when the specific surface area is smaller than 11 m ² / g, wetting with the synthetic resin 4 occurs. The problem is that the property is poor and the reinforcing effect is poor.

  In order to manufacture such a wooden bat 1 of this embodiment, for example, as shown in FIG. 3, the wooden bat main body 2 is placed in a resin impregnation apparatus 6, and the wooden bat 1 is made by a method such as vacuum or pressurization. A synthetic resin 4 is impregnated in the hitting ball 3 region of the bat body 2. Thereafter, the wooden bat main body 2 is taken out from the resin impregnation apparatus 6 and, as shown in FIG. 4, the hitting ball portion 3 region impregnated with the resin with a pair of semicircular molds 7 is heated and pressurized to cure the resin. In a normal manufacturing method of a compression bat such as caulking, means for mixing the above-mentioned fine carbon fibers 5 in a synthetic resin 4 impregnated in the wooden bat body 2 is provided.

  In the above-described embodiment, the example in which the hitting portion 3 region of the wooden bat main body 2 is reinforced with the synthetic resin 4 mixed with the fine carbon fiber 5 is described. However, the present invention is not limited to this, and the wooden bat main body is not limited thereto. 2 may be configured to be reinforced with the synthetic resin 4 in which the fine carbon fibers 5 are mixed.

  The wooden bat 1 of the present invention may be a compression bat as described in the above embodiment, or may be a resin injection bat without a pressure compression means.

Example 1
An epoxy resin having a viscosity of 50 cps is prepared as the synthetic resin 4, and an average fiber diameter of 150 nm, an average fiber length of 15 μm, and an aspect ratio (average fiber length / average fiber diameter) of 100 as fine carbon fibers 5 are prepared. 1% by mass of carbon nanofibers (Showa Denko Co., Ltd .: VGCF-fired type) exhibiting characteristics of 1500 W / (m · K) under a temperature state of a specific surface area of 13 m 2 / g and a thermal conductivity of 15 ° C. Synthetic resin material 8 mixed in the ratio was obtained. This was stored in a resin impregnation apparatus 6 as shown in FIG.
Moreover, as the wooden bat body 2, a Yachidamo material cut into a bat shape was prepared.

In this embodiment, first, as shown in FIG. 3, the wooden bat body 2 is placed in the resin impregnation device 6, and the hitting ball portion 3 region is immersed in the synthetic resin material 8. This dipping process is performed for approximately 2 minutes under a pressurized state (8 kgf / cm ² ).
Next, the wooden bat main body 2 is taken out from the resin impregnation device 6 and allowed to stand at room temperature for a while, so that the synthetic resin material 8 is thoroughly blended into the woody portion and the conduit portion of the wooden bat main body 2.
Thereafter, as shown in FIG. 4, the hitting portion 3 region of the wooden bat main body 2 is placed in the mold 7, and is heated and compressed at a temperature of 100 ° C. for about 20 minutes, whereby the wooden bat 1 of the present embodiment. Got.

  The wooden bat 1 cured and molded as described above did not cause voids or pinholes on the surface, had excellent molding quality, and did not require reworking in a subsequent process.

(Example 2)
In place of the fine carbon fiber 5 used in Example 1, the average fiber diameter is 30 nm, the average fiber length is 30 μm, the aspect ratio (average fiber length / average fiber diameter) is 1000, and the thermal conductivity is 15 ° C. A wooden bat was formed using a synthetic resin material 8 in which carbon nanotubes (CNRI) having a characteristic of 1700 W / (m · K) under the state were mixed in a synthetic resin at a ratio of 1% by mass.

  As in Example 1, the wooden bat cured and molded as described above had no voids or pinholes on its surface, was excellent in molding quality, and did not require reworking in a subsequent process.

(Comparative Example 1)
A synthetic resin material in which the fine carbon fiber 5 was not mixed was prepared, and a wooden vat was formed in the same manner as in Examples 1 and 2 using this material.

  In addition, when this bat was molded, a lot of synthetic resin material flowed out of the mold, and many voids and pinholes were generated on the surface of the cured wooden bat, which required a lot of reworking in the subsequent process. .

(Comparative Example 2)
In place of the fine carbon fiber 5 used in Example 1, the average fiber diameter is 1.0 μm, the average fiber length is 50 μm, the aspect ratio (average fiber length / average fiber diameter) is 50, and the thermal conductivity is 15 ° C. A wooden bat was formed using a synthetic resin material mixed with potassium titanate whisker (manufactured by Otsuka Chemical Co., Ltd .: Tismo D) having a characteristic of 5.3 W / (m · K) under temperature conditions.

  With respect to the wooden bats of Examples 1 and 2 and Comparative Examples 1 and 2, an actual hit test was performed in order to confirm the vibration damping property and rebound characteristics at the time of ball hitting and the durability performance. In this actual hitting test, a general amateur player was hit with the wooden bats of Examples 1 and 2 and Comparative Examples 1 and 2, and the feeling of hitting felt by the player at that time. While performing sensory evaluations such as (vibration transmitted to the hand) and resilience (flying), the durability was determined from the number of hits until the wooden bat was damaged. The results at this time are shown in Table 1 below.

  From these test results, the wooden bats of Examples 1 and 2 have sufficient durability performance compared to the wooden bats of Comparative Examples 1 and 2, and high vibration damping when hitting the ball. It was confirmed that the bat had excellent resilience characteristics.

The external appearance explanatory drawing of the wooden bat of a present Example. FIG. 2 is an explanatory diagram of a configuration in a region A of FIG. 1. Explanatory drawing showing the manufacturing method of the wooden bat of a present Example. Explanatory drawing showing the manufacturing method of the wooden bat of a present Example.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Wooden bat 2 Wooden bat main body 3 Hitting ball part 4 Synthetic resin 5 Fine carbon fiber 6 Resin impregnation apparatus 7 Mold 8 Synthetic resin material

Claims (5)

  In a wooden bat in which at least a part of the wooden bat body is reinforced with a synthetic resin, the synthetic resin has a single layer structure or a multilayer structure in which a crystal of a carbon hexagonal mesh surface is wound into a cylindrical shape, A wooden bat, which is a crystalline material having a fine hollow portion and is mixed with fine carbon fibers whose average fiber diameter is set within a range of 10 to 300 nm.   The viscosity of the synthetic resin at normal temperature is set within a range of 10 to 500 cps, and the fine carbon fibers are mixed in the synthetic resin at a ratio of 0.1% by mass or more and 10% by mass or less. The wooden bat according to claim 1.   The wooden bat according to claim 1 or 2, wherein a hitting portion of the wooden bat main body is reinforced by a synthetic resin mixed with the fine carbon fibers.   4. The wooden bat according to claim 1, 2, or 3, wherein the wooden bat is a resin-injected bat in which a synthetic resin mixed with the fine carbon fiber is injected and cured in a wooden bat body. The wooden bat according to claim 1, 2 or 3, wherein the wooden bat is a compression bat in which a synthetic resin mixed with the fine carbon fiber is injected and impregnated into a main body of the wooden bat and then compression-cured.

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