JP2576251B2 - Hollow impact buffer and hitting tool comprising the same - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to an impact buffering material capable of remarkably suppressing impact vibration generated by a collision between an object and an impact operation or the like.

(Prior art) Conventionally, various types of metal pipes, fiber reinforced plastic pipes, and the like have been manufactured, but these have been studied only with a focus on improving strength characteristics and weight reduction. There is no study on the problem of shock vibration.

Generally, impact vibration occurs when objects collide with each other, but there is no specific solution to such a special technique for controlling vibration at present.

(Problems to be Solved by the Invention) The most problematic field due to the generation of impact vibration is a hitting tool (tool, tool, instrument) that performs a desired job or play by performing a hitting operation. When a hitting operation is performed using such a hitting tool, a strong impact vibration is applied to a grip portion of the hitting tool.

If such impact vibration is continued for a long time, stiffness will remain on the wrist, arm, elbow, and the like, and if discomfort or fatigue due to the stiffness accumulates, the human body will eventually be damaged.

The present invention has intensively studied the problems caused by the above-described collision and impact.

That is, an object of the present invention is to provide a hollow material capable of remarkably suppressing impact vibration generated by a collision between objects and an impact operation.

Further, according to the present invention, for example, it is possible to solve the accumulation of discomfort and fatigue accompanied by stiffness remaining on the wrist, arm and elbow due to impact vibration at the time of impact, and to worry about obstacles such as elbow pain. Therefore, the hitting operation can be performed comfortably continuously for a long time.

(Means for Solving the Problems) The present invention employs the following means to achieve the above object.

That is, the hollow shock-absorbing material of the present invention is a laminate including a fiber-reinforced resin layer and at least one vibration-suppressing material layer having a vibration-loss coefficient at room temperature of 0.01 or more, which is made of an epoxy resin, a polyamide resin and an inorganic filler. And the outermost layer of the laminate is composed of the fiber reinforced resin layer.

In the hitting tool of the present invention, at least a part of the aggregate constituting the hitting tool is made of a fiber-reinforced resin layer, an epoxy resin, a polyamide resin and an inorganic filler, and has a vibration loss coefficient at room temperature of 0.01 or more. At least one vibration suppression material layer
It is characterized by being constituted by a hollow shock-absorbing material composed of a laminate including layers.

(Function) The present invention is to solve the problem of impact vibration caused by a collision between objects and an impact operation, and the like. It is play.

That is, the use of a hitting tool (tool, tool, instrument) is typical, and the present invention will be described below with the hitting tool as a representative.

Examples of such hitting tools include tools, martial arts tools, self-defense tools, and general sports tools.

Examples of tools include hammers, mallets, axes, etc.
Also, as martial arts equipment, for example, nunchaku, wooden sword,
Stick sticks and the like, and, as self-defense equipment, for example, a baton, etc., as general sports equipment, for example, rackets, hockey, ice hockey, cricket, such as tennis, tenipon, badminton and squash, Examples include sticks such as gate balls, hitting tools such as golf clubs and baseball bats. Of these hitters, tennis and golf are currently the most popular, and many people complain of elbow pain.
The hollow shock absorbing material of the present invention is preferably used as an aggregate for such sports rackets and clubs.

The present invention, when a composite hollow material comprising a vibration suppressing material and a fiber-reinforced resin containing the same is used as an aggregate constituting the hitting tool, unexpectedly suppresses the impact vibration at the time of hitting extremely small. It was completed after investigating the fact that it could be done.

As the above-mentioned fiber-reinforced resin, a material having sufficiently high strength and rigidity as an aggregate of a hitting tool, for example, a thermoplastic resin or a thermosetting resin can be used, but preferably, the thermosetting resin may have high rigidity. .

As thermoplastic resins, polyamide resins, polyester resins, polycarbonate resins, ABS resins, polyvinyl chloride resins, polyacetal resins, polyacrylate resins, polystyrene resins, polyethylene resins, polyvinyl acetate resins , Polyimide-based resins and the like and mixed resins thereof can be used.

As the thermosetting resin, an epoxy resin, an unsaturated polyester resin, a phenol resin, a urea resin, a melamine resin, a diallyl phthalate resin, a urethane resin, a polyimide resin, and a mixed resin thereof can be used. .

These fiber reinforced resins are preferably reinforced with inorganic fibers such as metal fibers, carbon fibers, and glass fibers, and reinforced fibers such as aramid fibers and other high-strength synthetic fibers. These reinforcing fibers may be used alone or in a mixed system thereof for reinforcement, and may be used in the form of long fibers, short fibers or a mixture thereof.

The vibration suppressing material referred to in the present invention is made of a specific resin composition comprising an epoxy resin, a polyamide resin and an inorganic filler, and has a vibration loss coefficient at room temperature of 0.01 or more, and attenuates shock vibration. It is the main part of the action that does.

Such a resin composition has an advantage that it can be processed into a desired shape, for example, a projection, a plate, a film, and the like, and is excellent in shock vibration suppression. Epoxy resin having fluidity at room temperature to 100 ° C, especially at room temperature to 100 ° C
A cured resin made of a resin composition containing a polyamide resin having fluidity at a temperature of at least one and at least one inorganic filler selected from graphite, ferrite and mica as a main component is preferably used.

That is, the epoxy resin having fluidity at room temperature to 100 ° C. is preferably a resin having at least two or more glycidyl ether groups, and more preferably has a viscosity at 25 ° C. of 1 to 300 poise and an epoxy equivalent of 100. ~ 50
0, those having a molecular weight of 200 to 1,000 are preferred. Specifically, for example, Epicoat 828, 827, 834, 807 (all manufactured by Yuka Shell Chemical Co., Ltd.) can be used.

Further, as a polyamide resin having fluidity at room temperature to 100 ° C., preferably, a viscosity at 25 ° C. of 3 to 2000 poise and an amine value of 100 to 800 are used as a curing agent for an epoxy resin, and after curing. It is effective because it effectively acts as a resin flexibility imparting agent. Specifically, for example, Tomide # 225-X, # 215-X, # 225 (these are Fuji Kasei Co., Ltd.)
), Versamide 930, 115 (all manufactured by General Mills), Epon-V15 (manufactured by Shell) and the like.

Such a polyamide resin acts as a curing agent for the epoxy resin, but in order to shorten the curing time and sufficiently promote the curing of the molded product, a commonly used curing agent for the epoxy resin can be used in combination. . Examples of the curing agent include aliphatic amines such as triethyltetramine, propanolamine and aminoethylethanolamine, aromatic amines such as P-phenylenediamine, tris (dimethylamino) methylphenol and benzylmethylamine, and furthermore phthalic anhydride, A carboxylic acid such as maleic anhydride can be used. The addition amount of such a curing agent may be an amount sufficient for curing in consideration of an epoxy equivalent, an amine equivalent, and an acid equivalent.

The inorganic filler to be filled in these resins is preferably at least one selected from graphite, ferrite and mica. Among these inorganic fillers, graphite is preferably used because of its excellent impact vibration suppression properties, and among them, those having an aspect ratio of 3 to 70 are preferred. The aspect ratio is a value obtained by dividing the diameter of the graphite particles by the thickness, and those in the above range may have excellent wettability to resin and mixing characteristics.

 The above components are preferably blended in the following proportions.

That is, the blending amount of the polyamide resin with respect to 100 parts of the epoxy resin is 100 to 800 parts, more preferably 200 to 500 parts.
Parts, and the inorganic filler is the total amount of these resins (including the monoglycidyl ether described below when it is blended)
The amount is 30 to 120 parts, more preferably 40 to 100 parts, per 0 parts.

In addition, when a monoglycidyl ether compound is further added to the above-mentioned resin composition, it is possible to provide a vibration-damping resin material which is extremely flexible and has good processability, and further provides a material having an excellent shock vibration damping effect. Is preferred. Particularly preferred are monoglycidyl ether compounds having an epoxy equivalent of 80 to 400 and a molecular weight of 80 to 400. Specifically, octadecyl glycidyl ether, phenyl glycidyl ether, butylphenyl glycidyl ether and the like can be preferably used.

The compounding amount of this compound is preferably 5 to 45 parts, more preferably 10 to 25 parts, per 100 parts of the epoxy resin.

A more preferable material as the vibration suppressing material in the present invention is a material having a vibration loss coefficient in a frequency range of 50 Hz to 5 kHz at room temperature of 20 ° C. of 0.02 or more, particularly preferably 0.04 or more.

 The above-mentioned vibration loss coefficient is measured as follows.

That is, a sample resin of 10 mm thickness is adhered to a steel plate of 5 mm thickness with a two-component epoxy adhesive, left for 24 hours, and then room temperature (20 μm) according to MIL-P-22581B of the U.S. military standard.
C)), the vibration attenuation waveform is measured, and the vibration loss equation coefficient (η) is determined by the following equation.

a. Decay rate (DECAY RATE) D ₀ (dB / sec) = (F / N) 20log (A ₁ / A ₂ ) b. Effective decay rate (EFFECTIVE DECAY RATE) De (dB / sec) = D ₀ -D . _B c limit attenuation factor (PERCENT cRITICAL dAMPING) C / Cc (%) = (183 × De) / F where, N: number of computationally taking period F: natural frequency a ₁ sample adhesive plate: N Maximum amplitude in medium A ₂ : Minimum amplitude in N D ₀ : Damping rate of sample adhesive plate D _B : Damping rate of original steel sheet d. Vibration loss coefficient (η) η = (C / Cc) / 50 Vibration of the present invention As an inhibitor, in addition to the above resin composition, the compression hardness at 25% compression specified in JIS K6767 is 5.0
A material of kg / cm ² or less, preferably 3.0 kg / cm ² or less can be used as a buffer. That is, such a shock absorbing material can be mixed or compounded with the vibration suppressing material to form an island component or a layer, or can be filled in a hollow portion to form a hollow impact shock absorbing material.

Here, the compression hardness is measured using a compression hardness tester (manufactured by Daiei Kagaku Seiki Seisaku-sho, Ltd.) in a temperature control room at 20 ° C.

The test piece used is a rectangular parallelepiped having a length of 50 mm, a width of 50 mm and a thickness of about 25 mm.

The thickness of the central part of the test piece was measured, and then the test piece was set at a predetermined position on a tester, compressed at 25% of the initial thickness at a compression speed of 10 mm / min., And stopped. The load after standing for 20 seconds in the state is measured, the stress is calculated by the following equation, and the stress value is determined as the compression hardness (H). In some cases, the compression hardness (stress value) may be determined with a smaller dimension (length, width) of the test piece.

Here, P: Load after 20 seconds under 25% compression (kg) w: Width of test piece (cm) l: 〃 Length (cm) As the cushioning material, use the materials listed below. However, the present invention is not limited to these.

Anhydrous elastomers: rubbery sulfur, silicon fluoride polymers, phosphorus-based, silicon-based (siloxane-based polymers), phosphazene-based elastomers (phosphorus and nitrogen are the skeleton), etc.

Polymer gel type: polyvinyl alcohol hydrogel, sodium acrylate / acrylamide copolymer gel, etc.

Organic elastomers: polyvinyl chloride, polyurethane, polyamide, polystyrene, ethylene vinyl acetate copolymer, ethylene ethyl acrylate, polyolefin, polyester, epoxy resins, etc.

Rubber elastomer: Natural rubber, styrene butadiene rubber, nitrile rubber, isoprene rubber, hydrin rubber, chloroprene rubber, etc.

Foamed plastics: Polyurethane-based, polystyrene-based, polyethylene-based, fluorine-based, EVA-based, phenol-based, PVC-based, and polyurea-based resins.

Next, the hollow shock absorbing material of the present invention is formed, for example, by laminating a fiber reinforced resin layer on a sheet made of a vibration suppressing material. As the fiber-reinforced resin, generally, a prepreg obtained by impregnating or coating a reinforcing fiber with a resin is used. Since such a polypreg exerts a stronger reinforcing effect in the orientation (arrangement) direction of the reinforcing fibers, when laminating, by changing the fiber arrangement angle of each prepreg, it is preferable to balance the reinforcing effect. Can be achieved.

Such a prepreg is a main component of an aggregate of a hollow shock absorbing material. For example, after winding the prepreg around a core bar (hollow or solid metal bar, resin bar), the vibration suppressing material sheet is formed. And then again wrap a few plies of prepreg. Note that any number of vibration suppressing material layers can be arranged at appropriate positions other than the outermost layer of the final product thickness. An example of such a molding method will be described below.

As one molding method, the rod-like material with the core rod obtained as described above is directly heated and molded.

As another molding method, the above-mentioned core rod may be used as it is as the core of the hollow shock absorbing material. The core material in this case is made of a core material made of a material to be practically used to form the above-mentioned wound body, which is fitted into a mold and heat-molded. For example, after winding a prepreg, a vibration-suppressing material, and a prepreg in the order of a synthetic resin tube such as nylon as a core material as described above, charging the molding die, and simultaneously pressing compressed air into the core material tube at the same time as heating. The tube is molded along the mold.

Instead of such a core material, a synthetic resin foamed by heating can be used as the core material. In this case, the resin is charged into a wound body composed of a prepreg and a vibration-suppressing material, and then molded as it is or charged into a mold and heated and foamed.

The hollow shock-absorbing material of the present invention is limited to an annular structure made of a fiber-reinforced resin material. That is, such a hollow material has a tendency that the shock vibration is amplified as compared with the solid material, but by combining a specific vibration suppressing material, the shock vibration can be effectively canceled. .

1 to 4 show typical examples of the structure, but the hollow shock absorbing material of the present invention is not limited to these structures.

The hollow shock-absorbing material 1 shown in FIG. 1 is an example in which a vibration-suppressing material layer 3 is arranged all around the middle layer of the aggregate composed of the fiber-reinforced resin layer 2. FIG. 2 is an example of a modification of the structure of FIG. 1, in which the vibration suppressing material layer 3 is arranged on a half circumference. FIG.
This is an example of a structure in which an intermittent portion is partially provided in the structure shown in the drawing. FIG. 4 shows an example of a structure in which the vibration suppressing material layers 3 are arranged in multiple layers.

Further, the hollow shock absorbing material of the present invention is characterized in that
The structure shown in the drawing may be variously combined, or may be a structure in which the vibration-suppressing material layer is arranged on a part of the aggregate in the axial direction.

The shape of the hollow shock-absorbing material may be any shape, in other words, it may be annular, and various shapes such as a circle, a triangle and a rectangle can be used.

The apparent vibration loss coefficient of the hollow shock absorbing material of the present invention thus obtained or a hitting tool using the same is preferably excellent impact vibration damping of 0.02 or more, more preferably 0.03 or more, and particularly preferably 0.04 or more. It is effective.

The method of measuring the apparent vibration loss coefficient is as follows.

That is, a micro-acceleration pickup is attached to one end of the sample or the center of the handle or grip of the tool and suspended, and the other end (head or zenith) of the sample or the tool is tapped with a hammer. The resonance frequency having the largest impact strength is detected. Next, a frequency filter near the detection resonance frequency is set, a new sample is dabbed with a hammer, and the attenuation waveform of the vibration is measured with an FFT analyzer (manufactured by Ono Sokki Co., Ltd.). MIL-P-225 by NEC Corporation
The vibration loss coefficient (η) is measured according to the formula of 81B.

(Examples) Hereinafter, the present invention will be described in more detail with reference to examples.

Example 1 and Comparative Example 1 As a tennis racket structural material, a glass fiber made of E glass and a carbon fiber were used in a weight ratio of 80/20 and an epoxy resin was used, and the fiber weight ratio was 65%. ^Two unidirectional prepreg sheets having a basis weight of 350 g / m ² were stacked in a ± 45 ° direction to form a 90 ° orthogonal prepreg sheet.

On the other hand, as a vibration suppressing material, the following resin composition was spread and cured to obtain a resin sheet having a thickness of 0.2 mm.

Epoxy resin (Epicoat # 828, Yuka Shell Co., Ltd.)
16.3 parts Octadecyl glycidyl ether 3.2 parts Polyamide resin (Tomide # 225-X, manufactured by Fuji Kasei Co., Ltd.) 38.3 parts Tris (dimethylamide) methylphenol 2.2 parts Graphite 40.0 parts The vibration loss coefficient of this resin sheet at 20 ° C is , 50Hz
And 0.04 in the frequency range from 5KHz.

This resin sheet was cut into a rectangle of 25 × 800 mm. The weight of the sheet was 5.6 g.

Subsequently, the prepreg sheet was cut into a rectangle of about 350 × 1600 mm and wound around a core of a nylon film tube. At this time, the resin sheet is the second layer from the outside,
In addition, a tubular laminated body was formed by arranging the tubular laminated body at the center of the tube.

Next, the tubular laminate was charged into a tennis racket mold and placed in a 130 ° C. curing oven. When the resin was softened, compressed air was injected into the nylon tube and cured for 2 hours, and then the molded product was taken out of the mold.

This molded product had a good appearance without swelling or voids. Further, after passing through processes such as deburring and surface polishing of the molded product, a grip and a gut were attached to form a tennis racket.

The weight of this racket was 355 g. As a result of measuring the apparent vibration loss coefficient of this racket, it was 0.22 at 20 ° C. and a resonance frequency of 137.5 Hz.

The shot feeling when this racket was used was such that the impact vibration transmitted to the wrist and elbow was extremely small as compared with the commercially available racket and that of the comparative example described later, and the ball could be hit comfortably.

For a comparative example, a conventional tennis racket was obtained in the same manner as in Example 1 without laminating the vibration suppressing material sheets (Comparative Example 1).

The weight of this racket was 349 g. As a result of measuring the apparent vibration loss coefficient of this racket, it was 0.007 at 20 ° C. and a resonance frequency of 142.5 Hz. The shot feeling when this racket was used was uncomfortable because the vibration transmitted to the wrist and elbow was large.

Examples 2 to 5, Comparative Example 2 As a vibration-suppressing material, the following resin composition having a thickness of 15
A 0μ resin sheet was used.

Epoxy resin (Epicoat # 828, Yuka Shell Co., Ltd.)
13.6 parts Octadecyl glycidyl ether 2.7 parts Polyamide resin (Tomide # 225-X, manufactured by Fuji Kasei Co., Ltd.) 31.9 parts Tris (dimethylamide) methyl phenol 1.8 parts Graphite 50.0 parts The above resin composition was 25 × 50 × As a result of molding and hardening to a size of 20 (mm) and measuring the vibration loss coefficient at 20 ° C,
It was 0.05 in the frequency range from 50Hz to 5KHz.

One of the prepreg, a carbon fiber bundle of a total fineness 3300D basis weight 139 g / m ² is arranged, to which a prepreg obtained by epoxy resin 207 g / m ² coating, as the arrangement direction of the carbon fibers is biased Cut pieces were prepared (prepreg A).

Another prepreg, a carbon fiber bundle of a total fineness 3600D is basis weight 150 g / m ² sequence, the prepreg obtained this by epoxy resin 244 g / m ² coating, and the arrangement direction of the carbon fibers straight part-length Was prepared (prepreg B).

First, the prepreg A is wrapped around a core bar made of a steel metal rod coated with a fluorine-based release agent by 6 ply, then the resin sheet is wrapped by 1 ply, and prepreg B is wrapped thereon by 4 ply to form a laminate. (Example 2).

Next, the resin sheet was wound around a core bar similar to that described above in the first ply, then the prepreg A was wound 6 ply, and the prepreg B was wound 4 ply thereon to form a laminate (Example 3). ).

Next, the prepreg A was wound around the core bar with 6 plies, then the prepreg B was wound with 4 plies, and finally the resin sheet was wound with 1 ply to form a laminate (Example 4).

Finally, the prepreg A is wound around the core bar with 6 plies, then the prepreg B is wound with 2 plies, the resin sheet is wound thereon with 1 ply, and finally the prepreg B is wound with 2 plies to form a laminate. (Example 5).

For comparison, 6 plies of prepreg A,
A laminate in which four layers of prepreg B were laminated was produced (Comparative Example 2).

Put the above five types of laminates in a high-temperature constant temperature
The epoxy resin was cured by heating for 2 hours, molded, and the metal bar was pulled out from the molded product to obtain five golf shaft materials.

Table 1 shows the results of measuring the apparent vibration loss coefficient of these golf shaft materials.

The apparent vibration loss factor in this case is a numerical value at a resonance frequency of 250 Hz at 20 ° C.

The materials of Examples 2 to 5, and particularly of Example 5, exhibited excellent shock vibration damping effects. When a golf club was made from these materials and the golf clubs were used, the shot feeling of each of the examples was much smaller than that of Comparative Example 2, and the impact vibration transmitted to the wrist and the elbow was much smaller. Was. In particular, Example 5
The clubs made of these materials were excellent.

(Effects of the Invention) The present invention remarkably controls the impact vibration generated by a collision or a striking operation, and makes it possible to extremely effectively transmit the impact vibration to a hand, a body, and a portion other than a portion subjected to an impact. A hollow impact buffer having a damping function can be provided.

INDUSTRIAL APPLICABILITY The hitting tool of the present invention is free from unpleasant vibration and stiffness, satisfactorily reduces fatigue of the arm and elbow due to impact vibration, does not accumulate such fatigue on the wrist, arm and elbow, etc. Can be. Further, it is expected to be a very useful material for applications that dislike impact vibration such as precision equipment.

[Brief description of the drawings]

1 to 4 are cross-sectional views showing an example of the structure of the hollow shock absorbing material of the present invention. 1: Hollow shock absorber 2: Fiber reinforced resin 3: Vibration suppressor

 ──────────────────────────────────────────────────続 き Continuation of the front page (56) References JP-A-1-1121074 (JP, A) JP-A-64-151 (JP, A) JP-A-1-152398 (JP, U) 23427 (JP, B2) JP-B 62-1988 (JP, B2)

Claims (6)

(57) [Claims] 1. A vibration-suppressing material layer comprising a fiber-reinforced resin layer and an epoxy resin, a polyamide resin, and an inorganic filler and having a vibration loss coefficient at room temperature of 0.01 or more.
A hollow impact cushioning material comprising a laminate including layers, wherein the outermost layer of the laminate is constituted by the fiber reinforced resin layer. 2. The hollow shock absorbing material according to claim 1, wherein the resin constituting the fiber reinforced resin layer is a thermosetting resin. 3. The hollow shock absorbing material according to claim 2, wherein the thermosetting resin is a resin selected from an epoxy resin and an unsaturated polyester resin. 4. The hollow shock absorbing material according to claim 1, wherein the vibration suppressing material is made of a material having a vibration loss coefficient at room temperature of 0.02 or more. 5. At least a part of the aggregate constituting the hitting tool,
Vibration loss coefficient at room temperature consisting of a fiber reinforced resin layer, a epoxy resin, a polyamide resin and an inorganic filler is 0.01
A hitting tool comprising a hollow impact buffer made of a laminate including at least one vibration suppressing material layer as described above. 6. The hitting tool according to claim 5, wherein the hitting tool is a racket or a golf club.