JP7238503B2 - Manufacturing method of tubular body - Google Patents

Description

TECHNICAL FIELD The present disclosure relates to a method for manufacturing a tubular body.

A tubular body made of fiber-reinforced resin can have high strength while being lightweight. This tubular body is useful in various applications.

There is a limit to weight reduction and strength enhancement. Manufacturing methods have been proposed to overcome this limitation. Patent Nos. 5,161,530, 5,113,726, 4,960,268 and 5,074,236 disclose methods of manufacturing tubular bodies using woven tapes as wrapping tapes.

Japanese Patent No. 5161530 Japanese Patent No. 5113726 Japanese Patent No. 4960268 Japanese Patent No. 5074236

The inventors have found a manufacturing method that can further improve the performance of tubular bodies. The present disclosure provides a method of manufacturing a lightweight, high-strength tubular body.

In one aspect, a tubular body manufacturing method comprises the steps of: obtaining an intermediate wound body by winding a fiber-reinforced resin material containing fibers and a matrix resin around a mandrel; A first wrapping step of winding a woven tape while applying a tension F1, a second wrapping step of winding a resin film tape around the outside of the woven tape while applying a tension F2, and the woven tape and the resin film tape are wound. A curing step of heating the intermediate wound body to cure the matrix resin, and after the curing step, pulling out the mandrel and removing the woven tape and the resin film tape are performed to obtain a cured tubular body. and a step. The 80° C. residual tightening force of the resin film tape in the curing step is 0.4 N/mm or more.

As one aspect, a lightweight and high-strength tubular body can be obtained.

FIG. 1 shows a golf club with a golf club shaft that is one embodiment of a tubular body. FIG. 2 shows a tubular body (shaft) used in the golf club of FIG. FIG. 3 is a process drawing showing an example of the tape wrapping process. FIG. 4 is a cross-sectional view of a spirally wound woven tape. FIG. 4 is a cross-sectional view along the axial direction of the tubular body. FIG. 5(a) is a plan view showing a test piece used for measuring residual stress, and FIG. 5(b) is a cross-sectional view taken along line AA in FIG. 5(a). FIG. 6 is an exploded view showing the laminated structure of cured tubular bodies used in all the examples and comparative examples.

Hereinafter, embodiments will be described in detail with reference to the drawings as appropriate.

The tubular bodies of the present disclosure have a variety of uses. Applications include golf club shafts, tennis racket frames, badminton racket frames, fishing rods, trekking poles, walking poles, canes, and the like.

FIG. 1 shows a golf club 2 using a golf club shaft 6, which is an example of a tubular body. The club 2 has a head 4, a shaft 6 and a grip 8. The head 4 is attached to the tip of the shaft 6 . A grip 8 is attached to the rear end of the shaft 6 .

FIG. 2 shows shaft 6 . The shaft 6 has a leading end Tp and a trailing end Bt. The outer diameter of the shaft 6 at the tip Tp is smaller than the outer diameter of the shaft 6 at the rear end Bt. The shaft 6 has a tapered portion whose outer diameter decreases toward the tip Tp. The shaft 6 has a centerline z1.

The material of the tubular body 6 is a sheet-like prepreg, that is, a prepreg sheet. In the present application, a prepreg sheet is also simply referred to as a sheet. In a typical prepreg sheet, fibers are oriented in one direction. The tubular body 6 is formed by winding and curing a plurality of prepreg sheets. The tubular body 6 is manufactured by a sheet winding manufacturing method. The manufacturing method of the tubular body 6 is not limited, and for example, the tubular body 6 may be manufactured by a filament winding manufacturing method.

An example of a method for manufacturing the tubular body (golf club shaft) 6 will be described below.

[Example of manufacturing process of tubular body]

(1) Cutting process In the cutting process, the prepreg sheet is cut into a desired shape. A plurality of sheets are cut out by this process. An example of cut sheets is shown in FIG. 6 below.

Cutting may be done by a cutting machine. Cutting may be done manually. For manual work, for example, a cutter knife is used.

(2) Bonding step If necessary, a plurality of sheets are bonded together to produce a united sheet.

(3) Winding process In the winding process, a mandrel is prepared. A typical mandrel is made of metal. A release agent is applied to the mandrel. Further, the mandrel is coated with a sticky resin. This resin is also called a tacking resin. A cut sheet is wound around this mandrel. The tacking resin facilitates the attachment of the sheet edges to the mandrel.

Each sheet is edge-attached to the winding object at a predetermined edge-attachment position. This wound object is then rolled. This winding may be done manually or by machine. This machine is called a rolling machine. The object to be wound is a mandrel or one or more sheets wound around a mandrel. All sheets are rolled to obtain an intermediate roll.

(4) Tape Wrapping Step In the tape wrapping step, a tape is wound around the outer peripheral surface of the intermediate roll. This tape is also called wrapping tape. The tape is wrapped under tension. In this embodiment, this tape wrapping process has a first wrapping process and a second wrapping process. Details of these steps will be described later.

(5) Curing Step In the curing step, the intermediate wound body after tape wrapping is heated. This heating cures the matrix resin. During this curing process, the matrix resin is temporarily fluidized. Voids between sheets or within sheets can be discharged by fluidizing the matrix resin. The pressure (tightening pressure) of the wrapping tape promotes the discharge of this void.

(6) Mandrel Pulling Process and Wrapping Tape Removing Process After the curing process, a mandrel pulling process and a wrapping tape removing process are carried out. As a result, a hardened tubular body is obtained. In this embodiment, the wrapping tapes are woven tapes and resin film tapes. From the viewpoint of improving the efficiency of the wrapping tape removing process, the wrapping tape removing process is preferably performed after the mandrel pulling process.

(7) Both ends cutting step In this step, both ends of the cured laminate are cut. This cut flattens the end face of the tip Tp and the end face of the rear end Bt.

(8) Polishing step In this step, the surface of the cured laminate is polished. Spiral irregularities are present on the surface of the cured laminate. This unevenness is a trace of the wrapping tape. Polishing can eliminate this irregularity and smooth the surface.

(9) Painting process The cured laminate after the polishing process is painted.

In the manufacturing method of this embodiment, a prepreg is used as the fiber-reinforced resin material. In this manufacturing method, a sheet-like prepreg (prepreg sheet) is wound around a mandrel. In addition to the prepreg sheet, the fiber-reinforced resin material includes tow prepreg, slit prepreg, and the like. This fiber-reinforced resin material may be a fiber bundle impregnated with a liquid resin.

A prepreg sheet includes fibers and a matrix resin. In this embodiment, the fibers are carbon fibers. The carbon fibers are oriented in one direction. This fiber may be other than carbon fiber. Carbon fiber is preferable from the viewpoint of forming a high-strength and lightweight tubular body.

[First lapping step and second lapping step]
In this embodiment, the tape wrapping process includes a first wrapping process and a second wrapping process. FIG. 3 is a process drawing showing the first lapping process St1 and the second lapping process St2. A second lapping process St2 is performed after the first lapping process St1.

In the first wrapping step St1, the woven tape TP1 is wrapped around the outer peripheral surface of the intermediate wound body 100 obtained in the winding step. A woven tape TP1 is wound while applying a tension F1. The woven tape TP1 is spirally wound. A double-headed arrow Pt1 in FIG. 3 indicates the spiral pitch Pt1 of the fabric tape TP1. A spiral pitch Pt1 is set so that no gap is formed. The pitch Pt1 can be set by the width W1 and the winding angle θ1 of the woven tape TP1. The winding angle θ1 is the angle between the longitudinal direction of the tape and the center line z1 of the tubular body 6 .

In the second wrapping step St2, the resin film tape TP2 is wound around the outside of the fabric tape TP1. The resin film tape TP2 is wound while applying tension F2. The resin film tape TP2 is spirally wound.

The tension F2 can change the width of the resin film tape TP2. The width of the resin film tape TP2 to which no tension is applied is W2. The width of the resin film tape TP2 in the wound state is W3. Width W3 is less than or equal to width W2.

What is indicated by a double arrow Pt2 in FIG. 3 is the spiral pitch Pt2 in the resin film tape TP2. The spiral pitch Pt2 is set so that no gap is formed. The pitch Pt2 can be set by the width W3 and the winding angle θ2 of the resin film tape TP2.

When the first wrapping step St1 and the second wrapping step St2 are completed, a layer of the woven tape TP1 is formed on the intermediate wound body 100, and a layer of the resin film tape TP2 is formed outside the layer of the woven tape TP1. . A layer of resin film tape TP2 adjoins a layer of textile tape TP1. A layer of resin film tape TP2 is in contact with a layer of textile tape TP1.

[Heating conditions in curing step]
As mentioned above, the curing step involves heating. From the viewpoint of accelerating the curing of the matrix resin, this curing step is preferably heated to a temperature of 60° C. or higher and 200° C. or lower, more preferably 70° C. or higher and 200° C. or lower, and 80° C. It is more preferable to heat to a temperature of 200° C. or higher.

Preferably, the curing step includes a first heating step and a second heating step. The curing process may consist of only the first heating step and the second heating step. After the first heating step, a second heating step is performed. The temperature of the first heating step is lower than the temperature of the second heating step.

In the first heating step, the matrix resin is fluidized. This fluidization can facilitate migration of the matrix resin to the woven tape. In addition, this fluidization facilitates the evacuation of voids. From these points of view, the temperature of the first heating step is preferably 60° C. or higher, preferably 70° C. or higher, and more preferably 80° C. or higher. From the viewpoint of suppressing the progress of excessive curing and promoting movement of the matrix resin, the temperature of the first heating step is preferably 115° C. or lower, preferably 100° C. or lower, and more preferably 90° C. or lower. The temperature of the first heating step may be 80°±10° or 80°±5°.

From the viewpoint of lengthening the time during which the matrix resin is fluidized, the time of the first heating step is preferably 10 minutes or longer, more preferably 15 minutes or longer, more preferably 20 minutes or longer, and more preferably 30 minutes or longer. From the viewpoint of tubular body productivity, the time of the first heating step is preferably 50 minutes or less, more preferably 40 minutes or less, and even more preferably 30 minutes or less.

From the viewpoint of promoting curing of the resin, the temperature of the second heating step is preferably 120° C. or higher, more preferably 125° C. or higher, and even more preferably 130° C. or higher. From the viewpoint of reducing energy costs, the temperature of the second heating step is preferably 200° C. or lower, more preferably 150° C. or lower. The temperature of the second heating step may be 130°±10° or 130°±5°.

From the viewpoint of advancing the curing of the resin, the time of the second heating step is preferably 10 minutes or longer, more preferably 15 minutes or longer. From the viewpoint of tubular body productivity, the time of the second heating step is preferably 240 minutes or less, more preferably 120 minutes or less, and even more preferably 60 minutes or less.

The temperature of the curing process can refer to the temperature of the air in the oven. The temperature of the curing process can refer to the surface temperature of the wrapping tape during the curing process.

[Wrap thickness]
In this application, the wrapping thickness of the woven tape TP1 is defined. FIG. 4 is a cross-sectional view of a spirally wound textile tape TP1. This FIG. 4 is a cross-sectional view along the center line z1 of the tubular body 6. As shown in FIG. The direction along the centerline z1 is also referred to as the axial direction. In addition, in FIG. 4, the thickness t1 of the woven tape TP1 is exaggerated and drawn large in order to make the drawing easy to see.

As shown in FIG. 4, the woven tape TP1 wound on a dashed line constitutes the layer 108 . A layer 108 of woven tape TP1 has an overlapping portion 110 and a non-overlapping portion 112 . Overlapping portions 110 and non-overlapping portions 112 are alternately arranged in the axial direction. In the overlap portion 110, the first winding portion TP11 and the second winding portion TP12 overlap. Therefore, the thickness of the overlapping portion 110 is twice the thickness t1 of the woven tape TP1. On the other hand, the thickness of the non-overlapping portion 112 is equal to the thickness t1 of the woven tape TP1.

A double-headed arrow Wa in FIG. 4 indicates the axial width of the woven tape TP1. This axial width Wa is determined by the width W1 of the woven tape TP1 and the winding angle θ1. The axial width Wa can be calculated by W1/sin θ1. A double-headed arrow Wb in FIG. 4 indicates the axial width of the overlapping portion 110 . A double arrow Wc in FIG. 4 indicates the axial width of the non-overlapping portion 112 . In the embodiment of FIG. 4, the following equation holds.
・Wa = Wb + Wb + Wc
・Pt1=Wb+Wc

In the woven tape TP1 thus formed, the winding thickness M1 is calculated by the following equation (1).
M1 = t1 x [(4 x Wb + Wc)/Wa] (1)

This winding thickness M1 is the average thickness of a layer of the textile tape TP1. Therefore, when the woven tape TP1 overlaps differently from that shown in FIG. 4, the average thickness can be calculated according to the overlap configuration.

By changing the pitch Pt1, the width Wb and the width Wc can be adjusted. Therefore, the winding thickness M1 can be adjusted by changing the pitch Pt1.

FIG. 4 shows the layer 108 of the woven tape TP1 with one turn. For example, if the number of turns is 2, layer 108 overlaps and the wrap thickness M1 is doubled. For example, if the number of turns is 3, the winding thickness M1 becomes 3 times. Thus, the winding thickness M1 can be adjusted also by the number of windings.

[Width W1 of woven tape TP1]
As FIG. 3 shows, the woven tape TP1 has a width W1. The width W1 is measured in a natural state where no external force is applied. However, in this embodiment, even if the tension F1 is applied, the width W1 does not change.

[Width W2 of resin film tape TP2]
The resin film tape TP2 has a width W2. The width W2 is measured in a natural state where no external force is applied.

[Width W3 of resin film tape TP2 after winding]
The tension F2 can change the width of the resin film tape TP2. As shown in FIG. 3, the wound resin film tape TP2 has a width W3. Width W3 is measured after being wrapped. The width W3 is also the width of the resin film tape TP2 when wound. Width W3 may be smaller than width W2 due to tension F2. The width W3 can be the same as the width W2 depending on the type and tension F2 of the resin film tape TP2. Width W3 is less than or equal to width W2.

[Tension F2]
As described above, the tension F2 is applied in winding the resin film tape TP2. This tension F2 increases the tightening pressure by the resin film tape TP2.

[Tightening force]
In this application, "clamping force" is defined. The tightening force of the resin film tape TP2 is obtained by dividing the tension F2 (N) by the width W3 (mm). The unit of tightening force is N/mm.

[effect]
The manufacturing method of this embodiment has the following effects.

[Resin Extraction Effect]
The intermediate wound body is tightened by the resin film tape TP2. When heated in the curing process, the matrix resin is fluidized and discharged from the prepreg. The matrix resin is discharged outside and absorbed by the fabric tape TP1. The woven tape TP1 has interstices between fibers, and the matrix resin enters into the interstices. As a result, the matrix resin is extracted from the prepreg.

The effect of removing the resin reduces the resin content, and weight reduction can be achieved.

Due to this resin extraction effect, the resin content of the tubular body can be made lower than the resin content in the winding process. Since the resin content of the prepreg can be made relatively high in the winding process, the winding work is facilitated, and the accuracy and efficiency of the winding work are enhanced.

[Void discharge effect]
In the winding process, air enters between the sheets (between the layers). This air becomes a void. Furthermore, voids also exist in the prepreg sheet. Voids reduce the strength of the tubular body. When the matrix resin is fluidized, voids are discharged from the intermediate wound body tightened by the resin film tape TP2. The reduction in voids increases the strength of the tubular body.

[Textile filling effect]
A fabric tape TP1 is interposed between the resin film tape TP2 and the intermediate roll. The fabric tape TP1 absorbs the matrix resin, but on the other hand, it relieves the clamping pressure of the resin film tape TP2. The fabric tape TP1 has a cushioning property, and this cushioning property relieves the tightening pressure of the resin film tape TP2. This mitigation can reduce the voiding effect. However, the woven fabric tape TP1 is impregnated with the resin, thereby deteriorating the cushioning properties of the woven fabric tape TP1. As the resin filling rate of the woven tape TP1 increases, the cushioning properties decrease. Due to the decrease in cushioning properties, the tightening pressure is less likely to be relaxed, and the void discharge effect is enhanced. This effect is also referred to as the fabric filling effect.

[Residual stress]
It was found that increasing the residual tightening force of the resin film tape TP2 at high temperatures increases the strength of the tubular body. It has been found that even if the winding tension F2 is increased, the void evacuation effect decreases when the residual tightening force decreases during heating in the curing process. By increasing the 80° C. residual tightening force and the 130° C. residual tightening force, the void discharge effect is increased and the strength of the tubular body is improved.

To calculate these residual clamping forces, the 80° C. residual stress and the 130° C. residual stress are measured. These residual stresses are measured by the following method. FIGS. 5(a) and 5(b) show a test piece 120 used for measuring residual stress. FIG. 5(b) is a cross-sectional view taken along line AA in FIG. 5(a). As the test piece 120, a resin film tape TP2 cut to a length of 180 mm is used. As grips, aluminum tabs 122 are attached to 40 mm long portions on both ends of the test piece. The aluminum tab is an aluminum plate with a thickness of 2 mm, a width of W4, and a length of 40 mm. Similarly, two aluminum tabs 122 are attached to the second end of the test piece 120 and the second end is sandwiched between the aluminum tabs 122 . The length of the pulled part is 100 mm. The width W4 of the test piece is the product width of the resin film tape TP2, and is the same as the width W2 described above.

A tensile tester (“AG-IS 500N (equipped with a constant temperature tester)” manufactured by Shimadzu Corporation) is used for the measurement. The aluminum tabs at both ends of the test piece 120 are gripped with jigs, and the test piece 120 is stretched at a displacement speed of 50 mm/min. When the tension reaches the tension F2 (N) in the example, the displacement is stopped and left as it is for 3 minutes, after which the heating conditions in the curing step of the example are reproduced. During heating under these heating conditions, the load at the end of the holding time at 80°C is the 80°C residual stress. Also, the load at the end of the holding time at 130°C is the 130°C residual stress. By measuring under actual heating conditions, a value corresponding to the actual residual stress in the curing process can be measured.

For example, the heating conditions in Examples described later are as follows. After raising the temperature from room temperature to 80° C. over 30 minutes, the temperature was maintained at 80° C. for 30 minutes, then the temperature was raised to 130° C. over 30 minutes, the temperature was maintained at 130° C. for 2 hours, and then the temperature was lowered to room temperature. Therefore, this heating condition is adopted also in the measurement of the residual stress in this example. That is, when the tension reaches the tension F2 (N) in the example, the displacement is stopped and left for 3 minutes, then heating is started and the temperature is raised to 80° C. in 30 minutes. Next, after holding the temperature at 80° C. for 30 minutes, the temperature is raised to 130° C. in 30 minutes. Next, after holding the temperature at 130° C. for 120 minutes, the heating is stopped and the temperature is lowered to room temperature. The load at the end of the holding time at 80°C is the 80°C residual stress. In this case, the load at 30 minutes after 80°C is the 80°C residual stress. The load at the end of the holding time at 130°C is the 130°C residual stress. In this case, the load when 120 minutes have passed since the temperature was set to 130° C. is the 130° C. residual stress. Note that the room temperature can be 20°C.

Thus, when the temperature condition of the curing step includes a holding time at 80° C., the residual stress at the time when the holding time has just finished is defined as the 80° C. residual stress. When the heating condition does not include the holding time at 80°C and only passes through 80°C, the residual stress at the time when the temperature reaches 80°C for the first time is taken as the 80°C residual stress. When the heating conditions include a holding time at 130° C., the residual stress at the time when the holding time has just finished is taken as the 130° C. residual stress. When the heating condition does not include the holding time at 130°C and only passes through 130°C, the residual stress at the time when the temperature reaches 130°C for the first time is taken as the 130°C residual stress.

[Residual tightening force]
A value obtained by dividing the residual stress (N) by the width W3 (mm) is defined as the residual tightening force. The unit of residual tightening force is N/mm. The 80°C residual tightening force is a value obtained by dividing the 80°C residual stress by the width W3. The 130°C residual tightening force is a value obtained by dividing the 130°C residual stress by the width W3.

[Growth rate]
It has been found that winding defects such as wrinkles can be suppressed by increasing the elongation rate of the resin film tape TP2. When spirally wound, if the elongation rate is small, slackness and wrinkles are likely to occur. It is even more so when the tubular body has a taper. By increasing the elongation rate, wrinkles and the like of the resin film tape TP2 can be suppressed. By suppressing wrinkles and the like, poor appearance of the tubular body is suppressed and the strength of the tubular body is increased.

Elongation is measured using the same specimen and equipment as for measuring residual stress. Similar to the residual stress measurement, the test piece 120 is used for measurement (see FIGS. 5(a) and 5(b)). The aluminum tabs at both ends of the test piece 120 are gripped with jigs, and the test piece 120 is stretched at a displacement speed of 50 mm/min. Displacement is stopped when the tension reaches F2 (N). The process up to this point is the same as the measurement of residual stress. The elongation rate is calculated based on this displacement amount. Assuming that the amount of displacement is X mm, the elongation rate (%) is calculated by [(100+X)/100]×100. By measuring the elongation at the tension F2 in this way, the actual elongation is accurately reflected.

From the viewpoint of strength and weight reduction of the tubular body, the 80° C. residual tightening force of the resin film tape is preferably 0.4 (N/mm) or more, more preferably 0.5 (N/mm) or more, and 0.6 (N/mm) or more is more preferable, and 0.7 (N/mm) or more is more preferable. Considering the strength of the resin film tape, the 80 ° C. residual tightening force of the resin film tape is preferably 10 (N / mm) or less, more preferably 8 (N / mm) or less, and more preferably 6 (N / mm) or less. Preferably, 4 (N/mm) or less is more preferable.

From the viewpoint of strength and weight reduction of the tubular body, the 130° C. residual tightening force of the resin film tape is preferably 0.3 (N/mm) or more, more preferably 0.4 (N/mm) or more, and 0.5 (N/mm) or more is more preferable. Considering the strength of the resin film tape, the 130 ° C. residual tightening force of the resin film tape is preferably 8 (N / mm) or less, more preferably 6 (N / mm) or less, and more preferably 4 (N / mm) or less. preferable.

If the elongation is small, winding defects such as wrinkles are likely to occur when spirally wound. This winding failure causes wrinkles or dents on the surface of the tubular body. Wrinkles and dents deteriorate the appearance. Additionally, wrinkles and dents can reduce strength. Also, a winding defect can cause uneven clamping force applied to the intermediate winding. From these points of view, the elongation percentage of the resin film tape due to the tension F2 is preferably 4% or more, more preferably 5% or more, and more preferably 6% or more. If the elongation rate is too large, the width W3 may become too small. From this point of view, the elongation rate of the resin film tape due to the tension F2 is preferably 50% or less, more preferably 45% or less, and even more preferably 40% or less.

From the viewpoint of increasing the resin absorption amount and enhancing the resin extraction effect, the winding thickness M1 of the woven tape is preferably 50 μm or more, more preferably 60 μm or more, more preferably 70 μm or more, and more preferably 80 μm or more. If the winding thickness is excessively large, the fabric filling effect described above may be reduced, and the tightening pressure of the resin film tape to the intermediate winding body may be reduced. As the tightening pressure decreases, the void evacuation effect decreases and the strength decreases. From the viewpoint of enhancing the fabric filling effect, the winding thickness M1 is preferably 400 μm or less, more preferably 300 μm or less, and more preferably 200 μm or less. From the viewpoint of reducing the weight of the tubular body, it is preferable to maximize the absorption amount of the resin. In this case, the winding thickness M1 may be 150 μm or more and 400 μm or less, or may be 200 μm or more and 400 μm or less.

Examples and comparative examples were tested using the following woven tapes and resin film tapes.
[Woven tape]
・Product name "Ester Satin" manufactured by Kinki Tape
・Product name “Ester Taffeta” manufactured by Kinki Tape
[resin film tape]
・Product name “PET 38K” manufactured by Shin-Etsu Film Co., Ltd.
・ Developed product "PT-30SD2" manufactured by Shin-Etsu Film Co., Ltd.
・Product name “PT-30H” manufactured by Shin-Etsu Film Co., Ltd.
・ Trade name “PET 75K” manufactured by Shin-Etsu Film Co., Ltd.
・ Trade name “PET 25K” manufactured by Shin-Etsu Film Co., Ltd.
・Product name “PET25” manufactured by Fujimori Industry Co., Ltd.
・Product name “W16-15” manufactured by Fujimori Industry Co., Ltd.

"Ester taffeta" is a plain weave woven tape, and "ester satin" is a satin weave woven tape.

[Example 1]
FIG. 6 shows the mandrel 126 and the prepreg sheet s1 or s6 used in Example 1. FIG. A tubular body according to Example 1 was produced according to the manufacturing process of the tubular body described above. After coating the mandrel 126 with a release agent, six prepregs s1 to s6 were wound around the mandrel 126 to obtain an intermediate wound body 100. FIG. The configuration of these six prepregs was as shown in FIG. The prepreg types and prepreg configurations of sheets s1 to s6 are shown in Table 1 below. Sheets s1 to s6 are all prepregs manufactured by Toray Industries, Inc. The "number of tip ply" in Table 1 indicates the number of turns of the prepreg at the tip Tp. "Fiber angle" in Table 1 is the orientation angle of carbon fibers with respect to the axial direction of the shaft. The matrix resin in each prepreg is an epoxy resin. The product number of each prepreg and the type (product number) of carbon fiber are as shown in Table 1.

Next, a first lapping process and a second lapping process were performed using a lapping machine manufactured by Yokote Iron Works. The first wrapping step is a step of winding the woven tape TP1 around the outer peripheral surface of the intermediate wound body 100 . The first lapping step was performed while applying tension F1. The second wrapping step is a step of winding the resin film tape TP2 around the outside of the wound fabric tape TP1 obtained in the first wrapping step. A second lapping step was performed while applying tension F2. The tension F1 and the tension F2 were measured by a load cell manufactured by Nidec-Shimpo Corporation.

In the first wrapping step, the above "ester satin" was used as the woven tape. This woven tape had a width W1 of 10 mm and a thickness of 80 μm. The tension F1 in the first lapping step was set to 40N. The winding angle θ1 and the pitch Pt1 were adjusted so that the winding thickness M1 was 80 μm.

After the first lapping step, a second lapping step was performed. In the second wrapping step, a resin film tape was wound. The above "PET 38K" was used as this resin film tape. This resin film tape had a width W2 of 20 mm and a thickness of 38 μm. The winding angle θ2 was set so that the pitch pt2 was 2 mm, and the pitch Pt2 was 2 mm. The tension F2 was set to 90N. Due to this tension F2, the width W3 after winding became smaller than the width W2 before winding, and was 12 mm.

After the second lapping step, a curing step was performed. In this curing step, the temperature was raised from room temperature to 80° C. over 30 minutes, held at 80° C. for 30 minutes, then raised to 130° C. over 30 minutes, held at 130° C. for 2 hours, and then It was allowed to cool to room temperature.

The mandrel 126 was then withdrawn. Next, the resin film tape and the fabric tape were removed to obtain a cured tubular body according to Example 1.

The specifications and evaluation results of Example 1 are shown in Table 2 below.

[Examples 2 to 23 and Comparative Examples 1 to 3]
Tubular bodies according to Examples 2 to 23 and Comparative Examples 1 to 3 were obtained in the same manner as in Example 1 except for the specifications shown in Tables 2 to 6 below. These specifications and evaluation results are shown in Tables 2 to 6 below.

[Measurement of residual stress, calculation of residual tightening force]
The 80° C. residual stress and 130° C. residual stress were measured by the method described above. By dividing these by the width W3 after winding, the 80° C. residual tightening force and the 130° C. residual tightening force were calculated. These values are shown in Tables 2-6 above.

[Measurement of elongation]
Elongation was measured by the method described above. This elongation is shown in Tables 2 to 6 above.

[Measurement of strength]
The 3-point bending strength of the tubular body was measured according to the SG type 3-point bending strength test. This is a test stipulated by the Product Safety Association of Japan. The strength at point B defined in this three-point bending strength test was measured. Point B is a point 525 mm from tip Tp. Indexes when the strength of Comparative Example 1 is 100 are shown in Tables 2 to 6 above.

[Appearance evaluation]
In Tables 2 to 6 above, in which the entire tubular body was visually confirmed, "x" indicates that dents or wrinkles were observed on the surface, and "x" indicates that no dents or wrinkles were observed on the surface. ○” is indicated.

[weight]
Indexes when the weight of Comparative Example 1 is 100 are shown in Tables 2 to 6 above.

Table 2 shows the specifications and evaluation results of Examples 1 to 6. Examples with high 80° C. residual clamping force and 130° C. residual clamping force tend to have relatively high strength. Example 6 with a small elongation rate has a low appearance evaluation. Example 5 with a small elongation has a small strength.

Table 3 shows the specifications and evaluation results of Examples 7-10. In Table 3, the winding thickness M1 is changed. In Example 10, in which the winding thickness M1 is 500 μm, the fabric filling effect is small and the strength is lowered.

Table 4 shows the specifications and evaluation results of Examples 11-17. In Table 4, the winding thickness M1 is changed, and the winding amount of the resin film tape is also changed. In Example 11, the resin film tape was wound twice. That is, in Example 11, after the resin film tape was spirally wound from the front end Tp to the rear end Bt, the resin film tape was wound again from the front end Tp to the rear end Bt. Therefore, in Example 11, it is described as "twice the amount of winding". The tightening pressure is increased by repeatedly winding the resin film tape. Example 12 was set to "3 times the amount of winding", and Examples 13, 15 and 17 were set to "4 times the amount of winding".

Comparing Example 11 with Example 7, in Example 11, the strength is improved by double winding the resin film tape. In other words, by setting the number of turns to 2, the strength is improved. In Example 12, in which the resin film tape is wound three times, the strength is further improved. In Example 14, in which the winding thickness M1 was set to 200 μm, weight reduction was achieved, but the strength was lowered. This is probably because the thick winding M1 enhanced the effect of extracting the resin, but reduced the effect of filling the fabric. Compared with the 14th embodiment, in the 15th embodiment, the strength is enhanced by winding the resin film tape four times. This is because the overwrapped resin film tape increases the clamping pressure and compensates for the reduced fabric filling effect. In Example 16, the winding thickness M1 is 400 μm, and the strength is greatly reduced. In comparison with this Example 16, in Example 17, the strength is enhanced by winding the resin film tape four times. Again, the overlapping wrapped resin film tape compensates for the reduced fabric filling effect.

By increasing the winding thickness M1 in this way, the effect of extracting resin is enhanced, and weight reduction can be achieved. Further, when the winding thickness M1 is increased, the effect of filling the fabric is reduced and the strength may be decreased. The resin film tape TP2 may be wound a plurality of times from the viewpoint of maintaining strength while emphasizing weight reduction. Considering production efficiency, the resin film tape TP2 is preferably wound in a single layer. Considering the balance between weight reduction and productivity, the resin film tape TP2 is preferably double to quadruple wound, more preferably double or triple wound, and more preferably double wound.

Table 5 shows the specifications and evaluation results of Examples 18-23. In Table 5, PET25 is used and the elongation rate is changed, and the 80° C. residual clamping force and the 130° C. residual clamping force are also changed. These examples also show a tendency for strength to decrease when elongation is low. It also shows a tendency for the strength to decrease when the two residual tightening forces are low.

Table 6 shows the specifications and evaluation results of Comparative Examples 1 to 3. In Comparative Example 1, no woven tape is used, and the weight is large. In Comparative Example 2, the 80° C. residual tightening force and the 130° C. residual tightening force are small, and the strength is low. Comparative Example 3 has a small elongation rate and two small residual tightening forces. Comparative Example 3 has low strength and poor appearance evaluation.

The following remarks are disclosed with respect to the above-described embodiments.
[Appendix 1]
a step of winding a fiber-reinforced resin material containing fibers and a matrix resin around a mandrel to obtain an intermediate wound body;
a first wrapping step of winding a woven tape around the outer peripheral surface of the intermediate wound body while applying tension F1;
a second wrapping step of winding a resin film tape around the outside of the woven tape while applying tension F2;
a curing step of heating the intermediate wound body around which the woven tape and the resin film tape are wound to cure the matrix resin;
After the curing step, pulling out the mandrel and removing the woven tape and the resin film tape to obtain a cured tubular body,
A method for manufacturing a tubular body, wherein the resin film tape has a residual tightening force at 80° C. of 0.4 N/mm or more in the curing step.
[Appendix 2]
The method for manufacturing a tubular body according to appendix 1, wherein the resin film tape has a residual tightening force at 130° C. of 0.3 N/mm or more in the curing step.
[Appendix 3]
3. The method for manufacturing a tubular body according to appendix 1 or 2, wherein the elongation rate of the resin film tape in the second wrapping step is 4% or more.
[Appendix 4]
4. The method for manufacturing a tubular body according to any one of Appendices 1 to 3, wherein the thickness of the woven tape wound in the first wrapping step is 400 μm or less.

2... golf club 4... head 6... golf club shaft (tubular body)
8... Grip 100... Intermediate wound body 108... Fabric tape layer 110... Overlap part 112... Non-overlap part TP1... Woven tape TP2... Resin film tape

Claims (7)

a step of winding a fiber-reinforced resin material containing fibers and a matrix resin around a mandrel to obtain an intermediate wound body;
a first wrapping step of winding a woven tape around the outer peripheral surface of the intermediate wound body while applying tension F1;
a second wrapping step of winding a resin film tape around the outside of the woven tape while applying tension F2;
a curing step of heating the intermediate wound body around which the woven tape and the resin film tape are wound to cure the matrix resin;
After the curing step, pulling out the mandrel and removing the woven tape and the resin film tape to obtain a cured tubular body,
A method for manufacturing a tubular body, wherein the 80° C. residual tightening force of the resin film tape determined based on the tension F2 and the heating conditions in the curing step is 0.4 N/mm or more. 2. The method for manufacturing a tubular body according to claim 1, wherein the residual tightening force at 130[deg.] C. of said resin film tape in said curing step is 0.3 N/mm or more. 3. The method for manufacturing a tubular body according to claim 1, wherein the elongation rate of the resin film tape in the second wrapping step is 4% or more. 4. The method for manufacturing a tubular body according to any one of claims 1 to 3, wherein the thickness of the woven tape wound in the first wrapping step is 400 [mu]m or less. The tubular body according to any one of claims 1 to 4, wherein the resin film tape has a residual tightening force at 80°C determined based on the tension F2 and the heating conditions in the curing step of 0.5 N/mm or more. manufacturing method. The method for manufacturing a tubular body according to any one of claims 1 to 5, wherein the resin film tape is double-wound, triple-wound or quadruple-wound. The method for manufacturing a tubular body according to any one of claims 1 to 6, wherein the woven tape has a winding thickness of 200 µm or more and 400 µm or less.

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