JPH05177014A - Racket frame for badminton and its manufacture - Google Patents

Abstract

PURPOSE:To simplify the manufacturing process and stabilize the quality by molding the ball drive section of a racket flame for badminton by the RIM molding method or the RTM molding method, and junction-molding the ball drive section to a shaft concurrently with its molding. CONSTITUTION:When a racket frame for badminton is to be molded, a ball drive section 8 is molded with continuous fibers and a crosslinkable material such as a polyaminoamide resin, epoxy-denatured polyaminoamide resin or polyesteramide resin by the RIM molding method or the RTM molding method, and the ball drive section 8 is junction-molded to a shaft 3 molded in advance to form the racket frame.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a badminton racket frame made of fiber reinforced resin and a method for manufacturing the same.

[0002]

2. Description of the Related Art A badminton racket frame (hereinafter abbreviated as a racket frame) made of fiber reinforced resin (hereinafter referred to as FRP) such as carbon fiber or glass fiber.
Is lightweight, has excellent strength, rigidity, impact resistance, and has a large degree of freedom in design, and has recently become the mainstream of racket frames. As these FRP racket frames, those manufactured by molding the respective components of the ball striking portion, the shaft portion, and the grip portion separately, and then joining and assembling them, or a mandrel coated with a tube for internal pressure molding. After forming a molded body covering the prepreg of a length corresponding to the frame portion and the shaft portion, and removing the mandrel from the molded body, place it in the racket frame molding die and compress the internal pressure molding tube. There is an internal pressure molding method in which it is expanded by air or the like and molded. In addition, a core molding material for a frame is covered with a prepreg, placed in a molding die, and pressure-heated and molded.

[0003]

The conventional FRP racket frame and the manufacturing method thereof have the following problems. That is, in the case where each member is separately molded and joined and assembled, the process is complicated and time-consuming because each member is separately molded, and when joining each member, particularly the hitting portion and the shaft portion, It was difficult to bond the racket frame without lowering its strength and without changing the various characteristics of the racket frame. In the internal pressure molding method, since the badminton racket frame has a thin inner diameter of each member of about 1 to 10 mm, a prepreg is wound around the core material tube and compressed air is injected into the tube. When press-molding the prepreg onto the inner wall of the mold by expanding, it is difficult to send sufficient pressure to every corner of the tube, and therefore, the FRP of each member
It was difficult to form the layer with a uniform thickness, which was also a cause of variations in quality.

In addition, in a case where a core material for molding a hitting portion is covered with a prepreg and placed in a mold to perform thermocompression molding, the core material is thin and the material used is a foam such as urethane resin. Therefore, it may be deformed by heat or molding pressure, and it is difficult to apply molding pressure to the prepreg,
Further, it is difficult to form the outer shell with a uniform thickness, and therefore, there is a problem in the strength of the frame. Further, in any of the above manufacturing methods, the racket frame for badminton has a remarkably small diameter of each member as compared with a racket frame for tennis etc. Therefore, the frame portion and the shaft portion are integrally molded. This is difficult, and each component must be molded separately, and must be completed by the method of joining and assembling. Therefore, the process is complicated and the cost is increased. Moreover, the physical and mechanical properties of the finished product were difficult to achieve as designed. Therefore, in view of these conventional drawbacks, the present invention has a simple manufacturing process, a short molding time, and
Keeping mechanical strength while being lightweight, making full use of the characteristics of RP,
It is an object of the present invention to provide a racket frame with little variation in these characteristics and a manufacturing method thereof.

[0005]

In order to achieve the above object, the racket frame of the present invention has the following structure. That is, in a badminton racket frame including a hitting portion, a shaft portion, and a grip portion, the outer shell of the racket frame has a continuous fiber as a reinforcing fiber, and a crosslinked polyaminoamide resin, a crosslinked epoxy-modified polyaminoamide resin, or a crosslinked polyesteramide resin. A material that can be produced,
RIM (reaction injection molding) molding method or RTM (resin transfer molding)
A racket frame molded by a molding method. As the reinforcing fiber used in the present invention, a fiber reinforcing material such as carbon fiber, glass fiber, aramid fiber or the like which is used in ordinary FRP molded articles can be used. These reinforcing fibers may be used alone or in combination in the form of being processed into products such as mats, woven fabrics, blades and preforms. The hitting portion may be hollow by a manufacturing method in which the meltable core material is removed after curing and molding, but it may be a solid body made of polymethacrylimide hard foam which is lightweight and does not deform due to heat or molding temperature.

As a method for producing the product of the present invention, first, the shaft portion is formed by a conventional sheet winding method in which a prepreg is wound around a mandrel for forming a shaft, and the sheet is pressed with a wrapping tape and then cured by heating. The shaft molding resin is preferably the same as the hitting portion molding resin. Next, a core material for forming a hitting portion is coated with reinforcing fibers to form a hitting portion molded body, and a mold is formed in a state where the ends of the separately molded shaft are clamped at both ends of the hitting portion molded body. To place. Then, after the mold is clamped, a molding resin material is injected into the gap between the core material and the mold, and the mixture is molded by reacting and curing in the mold. As the resin to be injected, a material which can form a crosslinked polyaminoamide resin, a crosslinked epoxy-modified polyaminoamide resin or a crosslinked polyesteramide resin, and a resin material having a low viscosity of 100 CPS or less is preferably used. As a device for injecting, the above resin material is separately mixed in two tanks of a main agent and a curing agent system, and the two liquids are mixed at the time of use and injected into a mold by a two-liquid method. When a meltable material is used for the core, a racket frame having a hitting portion with a hollow structure can be obtained by heating and removing after curing and molding.
A core material that can withstand molding heat and pressure in the molding method of the present invention,
For example, when a polymethacrylimide hard foam is used, a racket frame having a solid hitting portion is obtained.

[0007]

As described above, the racket frame of the present invention is
A material that can form crosslinked polyaminoamide resin, crosslinked epoxy-modified polyaminoamide resin or crosslinked polyesteramide resin. By molding by RIM molding method or RTM molding method, it has excellent impact resistance and elasticity compared to conventional epoxy resin. The racket frame is lightweight and has high toughness due to its high rate and compressive strength. Molding material viscosity is 1
Since it is not more than 00 CPS, the wetting with the reinforcing fiber is good, the content of the reinforcing fiber can be increased, and the adhesion at the time of molding the hitting portion and simultaneously joining and integrating with the pre-cured shaft is good. Further, according to the manufacturing method of the present invention, the shaft is preliminarily molded by a normal sheet winding method using a prepreg made of the same resin as that for molding the hitting portion, and the hitting portion is subjected to the RIM molding method or the RT method.
Since it is molded by the M molding method and is jointly molded with the shaft at the same time, the joint portion between the hitting portion and the shaft can be firmly joined and the diameter from the hitting portion to the shaft is continuous, so the elastic moduli of the two are separated. Not done. In molding the hitting portion, a low-viscosity molding material is injected into the mold and reaction-cured in the mold, so that the wetting of the reinforcing fiber is good and the impregnation is also good.
It can be increased to 0 to 80% by weight.

[0008]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT A preferred embodiment of the present invention will be described below with reference to the drawings. FIG. 1 is a front view of a racket frame according to this embodiment, and FIG. 2 is a sectional view taken along the line AA ′. The racket frame 1 of the present invention comprises a hitting portion 2, a shaft 3 and a grip 4, and an outer shell 5 is formed of a carbon fiber reinforced resin having a crosslinked epoxy modified polyaminoamide resin as a matrix. Inside the outer shell 5 of the hitting portion 2, a core material 6 made of a polymethacrylimide hard foam is built. Depending on the design, the inside of the outer shell of the hitting portion may be hollow.

FIG. 3 is a schematic explanatory view of a method for molding the racket frame 1. A crosslinked epoxy-modified polyaminoamide resin was used as the molding resin, carbon fiber was used as the reinforcing fiber, and polymethacrylimide hard foam was used as the core material. First, a core material 6 for forming a hitting portion is formed from a polymethacrylimide foam. The core material 6 is covered with a reinforcing fiber 7 made of carbon fiber to form a hitting ball molded body 8. As the form of the reinforcing fiber, a biaxial or triaxial blade was used. Then, the shaft 3 molded by the sheet winding method with a prepreg formed by impregnating carbon fiber with a molding resin similar to the ball hitting portion is sandwiched between both ends of the ball hitting molded body 8 and the molds 10 and 11 are formed. Place and close the mold. At this time, if the portion where the hitting ball portion and the shaft are joined is covered in advance with a substantially T-shaped joining member 9 having a tubular portion into which both ends of the shaft and the hitting portion can be inserted, the joining portion can be molded in a continuous state. After that, a material capable of forming a crosslinked epoxy-modified polyaminoamide resin was injected into the gap between the core and the mold in the closed mold, and the mixture was reacted and cured in the mold to obtain a racket frame 1.

[0010]

As described above, since the racket frame of the present invention is a racket frame made of a crosslinked polyaminoamide resin, a crosslinked epoxy-modified polyaminoamide resin or a crosslinked polyesteramide resin as the matrix resin, the conventional epoxy resin, etc. Compared to, the racket frame is superior in impact resistance, elastic modulus, and compressive strength, and thus becomes a lightweight and tough racket frame with improved durability. or,
The viscosity of the material to be injected into the mold is as low as 100 CPS or less, and because it is cured by reaction in the mold, it wets well with the reinforcing fiber, so it is easy to impregnate the reinforcing fiber even if the hitting frame has a small diameter. In addition, the thickness of the outer shell can be made uniform and the quality is stable, and the content of reinforcing fibers can be increased, which improves the degree of freedom in design. Further, since the hitting portion is molded by the RIM molding method or the RTM molding method, and at the same time, it is joined and molded with the shaft which is previously molded with the same resin as the resin for molding the hitting portion, the joining is strong and the hitting portion and the shaft portion are Since there is no risk of separation by the connecting members or uneven wall thickness as in the past, the elastic modulus is not separated from the ball hitting portion to the shaft portion, and it is a racket frame with good operability and moderate flexibility. Become.

[Brief description of drawings]

FIG. 1 is a front view of a racket frame for badminton of the present invention.

FIG. 2 is a sectional end view taken along line AA-A ′ of FIG.

FIG. 3 is a schematic explanatory view of a molding method.

[Explanation of symbols]

 1 Badminton racket frame 2 Ball hitting part 3 Shaft 4 Grip 5 Outer shell 6 Core material 7 Reinforcing fiber 8 Ball hitting part molded body 9 Joining member 10 Mold

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Teruyuki Sugita 3877-8 Takada, Yoro-cho, Yoro-gun, Gifu Mitsuno Co., Ltd.

Claims (2)

[Claims] 1. A badminton racket frame comprising a ball striking portion, a shaft portion and a grip portion, wherein the outer shell of the racket frame has a continuous fiber as a reinforcing fiber, a crosslinked polyaminoamide resin, a crosslinked epoxy modified polyaminoamide resin or a crosslinked polyester. A racket frame for badminton, which is a material capable of forming an amide resin and is molded by a RIM molding method or an RTM molding method. 2. A method for manufacturing a badminton racket frame comprising a ball striking portion, a shaft portion and a grip portion, wherein a core material for molding a ball striking portion is coated with reinforcing fibers to form a ball striking portion molded body, Placed in the mold with the separately molded shaft part sandwiched at both ends of the ball striking part molded body, crosslinked polyaminoamide resin, crosslinked epoxy modified in the gap between the core material and the mold in the closed mold A method for producing a racket frame for badminton, which comprises molding a racket frame by injecting a low-viscosity material capable of forming a polyaminoamide resin or a crosslinked polyesteramide resin and curing the mixture by reaction in a mold.