JP2005131838A - Tubular body and its manufacturing method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To easily manufacture a tubular body having lightweight properties and high rigidity with good moldability. <P>SOLUTION: The tubular body is manufactured by a process for laminating fiber-reinforced resin layers each of which comprises reinforcing fibers and a thermosetting resin to form a tubular preform, a rotation control process for rotating the preform while heating the same to a temperature below the curring temperature of the thermosetting resin to allow the resin in the preform to flow to the outside in the diametric direction of the preform by centrifugal force not only to fill the gap, which is not filled with the resin in the preform, with the resin but also to control the resin content on the outer surface side so as to increase the same, a curing process for heating the preform controlled in resin content to the curing temperature of the thermosetting resin during or after rotation to cure the same to obtain the tubular body and a grinding process for grinding the outer surface increased in resin content of the tubular body. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a tubular body manufacturing method and a tubular body, and more particularly, to improve the resin distribution in a manufacturing process of a fiber reinforced resin tubular body used for a golf club shaft or the like, and to obtain a lightweight and highly rigid tubular body. It is easy to mold.

Tubular bodies used for golf club shafts, tennis and badminton rackets, fishing rods and the like are mainly formed using a fiber reinforced resin material such as carbon prepreg. Since these materials have high strength, moderate flexibility, and are light in weight, various types of tubular bodies having functions suited to the purpose have been proposed.
From the viewpoint of improving operability, there is a strong demand for weight reduction, and in recent years, the demand has further increased with the increase of users such as elderly people and women. It is requested.

Such a golf club shaft is formed by winding a prepreg obtained by impregnating a reinforcing fiber such as carbon fiber with a synthetic resin such as an epoxy resin around a mandrel, and applying pressure and heating. In order to produce a lightweight and high-strength shaft, a prepreg having a low resin content is used in order to increase the content of reinforcing fibers.
When a prepreg having a low resin content is used, the rigidity can be increased and the weight can be reduced because of a large amount of fiber, but on the other hand, there is a problem that the prepreg is difficult to wind and the moldability is poor because the resin content is small. is there. In addition, there is a problem that the adhesion is deteriorated at the boundary of the prepreg winding layer, voids (voids) are generated at the boundary, and the strength is easily lowered.

  On the other hand, when a prepreg having a high resin content is used, since the resin content is large, the prepreg is easy to wind and the moldability is improved. However, on the other hand, the weight is increased and the fiber content is relatively small, resulting in low rigidity. There is a problem. In addition, there is a problem that there is no fiber or a portion where the presence of fiber is extremely small and a resin pool is formed, and delamination or cracks are likely to occur.

From the viewpoint described above, conventionally, a tubular body having a desired performance may be formed by using prepregs having different resin contents.
For example, in Japanese Patent Application Laid-Open No. 8-207166 (Patent Document 1), there are a resin amount poor region and a resin amount rich region in the thickness direction, and the average impregnation amount of the resin is within a range of 10 wt% to 20 wt%. It has been proposed to manufacture a tubular body by winding a prepreg having the above value and pressurizing and heating from the outside with a tightening body.
In JP-A-8-98906 (Patent Document 2), a tape-like or sheet-like film made of an organic polymer is used as a reinforcing material on the outermost layer of the shaft main body and wound only on the chip side. A golf club shaft manufacturing method has been proposed.

  However, in Patent Document 1, since there is a resin-rich portion in the prepreg, the weight increases accordingly. Further, when the outer peripheral surface of the tubular body is polished, the fiber component is also scraped together with the resin component in the outermost prepreg, so that there is a problem that rigidity and strength are lower than before the polishing. Furthermore, it is necessary to separately prepare a prepreg having a resin amount poor region and a resin amount rich region in the thickness direction, and there is a problem that the moldability is poor.

Further, in Patent Document 2, a resin film not containing fiber is wound only on the outermost layer on the chip side, but since it does not contain fiber, rigidity cannot be improved, and improvement in impact strength is insufficient. It is. Moreover, a weight increase is caused by the resin film, and there exists a problem that weight reduction and high rigidity cannot be made compatible as a whole tubular body.
JP-A-8-207166 JP-A-8-98906

  The present invention has been made in view of the above-described problems, and it is an object of the present invention to provide a method for producing a tubular body that can easily obtain a lightweight and highly rigid tubular body and has excellent moldability.

In order to solve the above problems, the present invention includes a step of laminating a fiber reinforced resin layer composed of a reinforced fiber and a thermosetting resin to form a tubular preform,
The preform is rotated while being heated below the curing temperature of the thermosetting resin, and the resin in the preform is caused to flow radially outward by centrifugal force so that the resin in the preform is filled. A rotation control step for controlling the outer surface side resin content to be increased while filling the voids not filled with resin;
A curing step in which the preform with the resin content controlled is heated at or above the curing temperature of the thermosetting resin during or after the rotation to obtain a tubular body;
A polishing step for polishing the outer surface of the tubular body having a high resin content;
The manufacturing method of the tubular body containing this is provided.

By rotating an uncured fiber reinforced resin tubular preform with its axis as the axis of rotation, centrifugal force acts on the preform, and in the radial direction, the fiber component in the fiber reinforced resin However, a resin component having a large specific gravity flows toward the outer peripheral side relative to the fiber component. For this reason, the resin content rate on the inner peripheral side can be decreased and the resin content rate on the outer peripheral side can be increased as compared to before rotation. Further, the resin can be filled into voids that are not filled with the resin, and the resin content can be made uniform in the circumferential direction of the preform in the rotation control step.
Also, since the outer surface with a high resin content is polished, the resin component that causes an increase in weight can be cut and the weight can be reduced. At the same time, the fiber component is not cut, thus reducing the weight without reducing the rigidity. can do. Furthermore, it is possible to prevent the occurrence of resin pools and voids that cause a decrease in the strength of the tubular body, and the strength can be increased.

  The forming step of the tubular preform with the fiber reinforced resin layer laminated may be formed by a sheet winding method or a filament winding method. In the rotation control step, the mandrel may be rotated in a state where the preform is wound around the mandrel, or the cylindrical container may be rotated by being accommodated in the cylindrical container.

Preferably, the preform may be formed by winding a plurality of prepregs in which a mandrel is impregnated with a thermosetting resin in a reinforcing fiber and then rotating the mandrel. By the rotation of the mandrel, the preform on the outer periphery of the mandrel is rotated, and the resin content is gradually increased from the inner periphery side to the outer periphery side by controlling the rotation speed and the heating temperature. be able to.
By increasing the resin content on the outer peripheral side relative to the inner peripheral side, voids can be eliminated particularly on the outer peripheral side where a large bending stress or torsional stress is applied, and durability can be improved.

As the plurality of prepregs, those having approximately the same resin content are used.
In the present invention, it is necessary to prepare a plurality of prepregs having different resin contents because the resin content ratio in the preform can be controlled in the radial direction by the rotation control step even if prepregs having the same resin content are used. Therefore, the material type can be reduced, the material cost is reduced, and the production efficiency is improved. Further, even when a prepreg having a high resin content is used, the amount of resin on the outer surface to be polished is increased, so that a tubular body having a low rigidity and a low resin content that can realize weight reduction can be formed.
It goes without saying that prepregs having different resin contents may be used according to the required performance of the tubular body to be manufactured.

  In the thickness portion from the outer surface to 20% of the entire thickness of the tubular body before the polishing step, the resin content after the rotation control step is 120% to 200% with respect to the resin content before the rotation control step. It is controlled to become%

In the polishing step, the range from the outer surface to a distance of 20% of the thickness in the radial direction is a region that may be polished. Therefore, when the resin content of this portion is increased, the change in rigidity of the tubular body due to polishing can be suppressed, the resin content of the tubular body after polishing is reduced, and a lightweight, high-rigidity tubular body can be obtained. it can. The amount of polishing can be changed according to the required performance of the tubular body, and the entire outer peripheral surface of the tubular body may be polished or partially polished.
In the above region, the resin content after the resin amount adjustment step is increased to 120% to 200% of the resin content before the rotation control step. This is because the rigidity and strength are easily changed by polishing. On the other hand, if it is made larger than 200%, the change in the resin amount becomes too large, and the time required for the rotation control process becomes longer and the productivity deteriorates. In addition, it is preferable that the resin content rate by the said rotation control process shall be 120%-150%.

  A mandrel is formed with a small diameter at one end in the axial direction and a large diameter at the other end. If it is formed as a tapered tubular body, the resin flow rate from the inner diameter to the outer periphery is larger on the larger diameter side than on the smaller diameter side in the rotation control step. A tubular body having a high height can be obtained.

  After the rotation control step and the heat curing step, and before the polishing step, the resin content in the range from the outer peripheral surface of the tubular body to 10% of the thickness in the radial direction is 50% to 100%, preferably 80% to 100%. It is said. This is because in a region that may be polished, if the resin content is less than 50%, the fiber content is large, so that the fiber component is polished and the rigidity and strength are likely to decrease. From this viewpoint, the above range is optimally set to 100% resin content.

  The rotation speed in the rotation control step is 30 rpm to 1500 rpm, preferably 300 rpm to 1500 rpm. This is because if the rotational speed is less than 30 rpm, the centrifugal force does not act sufficiently, and the resin is difficult to flow to the outer peripheral side. On the other hand, even if it exceeds 1500 rpm, the flow of the resin to the outer peripheral side cannot be accelerated, and high-speed rotation of the metal mandrel is difficult. The rotation speed may be constant or may be changed in stages.

The heating temperature in the rotation control step for causing the thermoplastic resin to flow is preferably lower than the curing temperature of the resin used and the temperature at which the viscosity of the resin used decreases. For example, when the thermosetting resin is an epoxy resin, the rotation is good while heating at a resin temperature of 40 ° C. to 100 ° C., preferably 50 ° C. to 80 ° C., and then stepwise up to the curing temperature. Heating is good.
In the rotation control step, it is preferable that a resin film such as polypropylene or polyethylene is wound around the outer peripheral surface of the preform and pressurized, and then heated and rotated.

  The prepreg to be laminated is used in combination with a prepreg such as a bias layer having a fiber angle of 10 to 70 degrees, a straight layer having a fiber angle of 0 to 10 degrees, and a hoop layer having a fiber angle of 70 to 90 degrees relative to the axial direction. The fiber configuration of the reinforcing fibers, the laminated position such as the arrangement position, length, width, and thickness of each layer can be set according to the required performance of the tubular body. You may combine the prepreg over the full length of an axial direction, and the prepreg arrange | positioned partially.

The thickness of the prepreg is preferably 0.01 mm to 0.3 mm, more preferably 0.05 mm to 0.15 mm, and the elastic modulus of the prepreg is preferably 5 ton / mm ^{2 to} 100 ton / mm ² . Furthermore, the bending strength is preferably from 100kgf / mm ² ~200kgf / mm ² at 0 degrees with respect to the axial direction, the resin weight per unit area of the prepreg is ^{5g / m 2 ~500g / m 2} , carbon fiber basis weight is 5 g / m ^{2 to} 300 g / m ² is preferable.

  The resin content of the prepreg used is preferably 10% by weight to 50% by weight. This is because if the thickness is smaller than this range, the tackiness is small and it is difficult to wind the prepreg, and if it is larger than this range, the polishing amount increases, the productivity is deteriorated, and the weight reduction is difficult to realize. More preferably, it is 20 to 40 weight%, More preferably, it is 20 to 30 weight%.

  Examples of reinforcing fibers include carbon fibers, glass fibers, various ceramic fibers, boron fibers, metal fibers such as copper and stainless steel, amorphous fibers, organic fibers such as aromatic polyamides (for example, Kevlar fibers, Tyranno fibers), and the like. A mixed fabric or the like can be used. Among these, carbon fiber and glass fiber are preferable, and carbon fiber is particularly preferable. The thickness of the reinforcing fiber is preferably 3 μm to 13 μm, and more preferably 3 μm to 4 μm. The reinforcing fibers can be used in any shape / arrangement such as a single direction, a random direction, a sheet shape, a mat shape, a woven (cross) shape, a braided shape, and the like.

  As the thermosetting resin, an epoxy resin, a phenol resin, a vinyl ester resin, a polyester resin, an unsaturated polyester resin, or the like can be used, and a resin having a large specific gravity is preferable. Of these, epoxy resins and phenol resins are preferable, and epoxy resins are particularly preferable.

The present invention provides a tubular body manufactured by the above manufacturing method.
In the tubular body, since the resin component flows to the outer periphery in the radial direction by centrifugal force in the rotation control process, voids that are not filled with the resin in the tubular body can be eliminated, and at the same time, the resin in the resin reservoir has an outer diameter. By flowing to the side, it is possible to eliminate a resin reservoir, and it is possible to provide a tubular body with uniform physical properties and high durability. Moreover, since the part with high resin content rate of an outer surface is grind | polished, it can be set as a highly rigid tubular body with low resin content rate as a whole, and lightweight.
As a result, it can be particularly suitably used as a golf club shaft, and can also be used for tennis or badminton rackets, fishing rods, ski stocks, and the like.

  As described above, according to the present invention, the resin content can be made uniform in the circumferential direction in the preform by rotating the shaft center as the rotation axis while heating the uncured preform. In the radial direction, the resin content can be gradually increased from the inner peripheral side toward the outer peripheral side.

  After curing the preform with the resin content controlled in this way, the outer peripheral side having a large resin content is polished, so that the fiber portion is not scraped by polishing, and a rigid tubular body is easily obtained. be able to. Moreover, a lightweight and highly rigid tubular body can be easily manufactured without using a prepreg having a low resin content that is difficult to mold as in the prior art. Furthermore, since no voids or resin pools are generated, the durability of the tubular body can be improved.

  Further, when the tubular preform is tapered with one end in the axial direction having a small diameter and the other end having a large diameter, the resin content of the outer periphery can be increased on the large diameter side than on the small diameter side. In other words, since the fiber content of the outer periphery on the small diameter side can be made higher than that on the large diameter side, the impact resistance can be increased, and the resin content can be increased on the large diameter side, so that the durability can be increased. Therefore, when applied to a golf club shaft, the impact resistance on the head mounting side on the small diameter side can be improved, while the outer periphery on the grip mounting side on the large diameter side has a high resin content to improve durability. Moreover, since the outer surface having a high resin content is polished regardless of the small-diameter side and the large-diameter side, the weight can be reduced, and it can be suitably applied particularly to a golf club shaft.

Hereinafter, the manufacturing method of a tubular thing is explained with reference to drawings as an embodiment of the present invention.
First, in the preforming step, a preform formed of a laminate of fiber reinforced resin including reinforced fibers and a thermosetting resin is formed.
As shown in FIGS. 1A and 1B, the preform is formed by winding a plurality of layers of prepregs 11 to 14 in which reinforcing fibers are impregnated with a thermosetting resin around a mandrel 10. The mandrel 10 has a circular cross section, and has a tapered shape in which one end 10a has a small diameter, the other end 10b has a large diameter, and the outer diameter gradually increases from the small diameter side to the large diameter side. The reinforcing fibers F11 to F14 of the prepregs 11 to 14 are all made of carbon fiber, and an epoxy resin is used as the matrix resin.

In the prepregs 11 and 12, the fiber angles formed by the reinforcing fibers F11 and F12 with respect to the axial direction are + 45 ° and −45 ° (angle layer), respectively, and each of the prepregs 11 and 12 has three turns. The prepreg 13 has a fiber angle of 0 ° (straight layer) formed by the reinforcing fibers F11 with respect to the axial direction and is wound twice.
The prepreg 14 has a fiber angle formed by the reinforcing fiber F14 with respect to the axial direction of 0 ° and is wound three times.
The number of windings of the prepregs 11 to 14 is common from the front end to the rear end. Each prepreg 11-14 has a resin content of 20% by weight, a thickness of 0.1 mm, and an elastic modulus of 30 ton / mm ² . Further, the resin basis weight of the prepreg is 150 g / m ² , the carbon fiber basis weight is 100 g / m ^2, and the bending strength at 0 degrees with respect to the axial direction is 155 kgf / mm ² .

  Specifically, the prepregs 11 to 14 are wound around the outer peripheral surface 10 c of the mandrel 10 in order from the inner layer side and laminated to form a tubular preform 20. The preform 20 is laminated so that one end 20a in the axial direction has a small diameter and the other end 20b has a large diameter, and the outer diameter and inner diameter gradually increase from the one end 20a to the other end 20b, and the thickness is constant.

  As shown in FIG. 2, the resin content in the radial direction of the preform 20 before the rotation control step is uniform from the inner peripheral side 20 a to the outer peripheral side 20 b of the preform, and the resin content 21 and the fiber content 22. The ratio is constant.

  After the preform 20 is formed by the sheet winding method using the prepreg described above, a polypropylene tape (not shown) is wound around the outer peripheral surface of the preform 20 at a pitch of several mm while applying a certain tension. The preform 20 is pressed from the outer peripheral surface side.

Next, as shown in FIGS. 3 and 4, in the rotation control step, the mandrel 10 is rotated, and the preform 20 on the outer peripheral surface of the mandrel 10 is rotated. At this time, the thermosetting resin is heated and held in a state where the fluidity is maintained at a temperature lower than the curing temperature, and is rotated as indicated by an arrow in the drawing with the axis i as the rotation axis. With this rotation, the centrifugal force of the preform 20 acts, and the resin portion 21 having a specific gravity larger than the fiber portion 22 in the fiber reinforced resin flows relative to the fiber portion 22 toward the outer peripheral side 22b. Thus, the resin content is controlled from the state of FIG. 2A to the state of FIG.
Thereafter, the preform 20 'having the resin content adjusted is heated and cured at a temperature equal to or higher than the curing temperature of the thermosetting resin while rotating to obtain a tubular body. .

  As shown in FIG. 4, the resin content in the tubular body 20 ′ cured in this state is flowed from the inner peripheral side 20 a ′ to the outer peripheral side 20 b ′. As compared to before the rotation control step, the fiber portion 22 is larger on the inner peripheral side 20a ′ and the resin portion 21 is larger on the outer peripheral side 20b ′.

Specifically, in the present embodiment, the mandrel 10 is gripped on the large diameter side, and a rotational torque is applied by a motor (not shown) to rotate the mandrel 10 around the axis. The center i is rotated at 500 rpm about the rotation axis.
Heating is started at the start of rotation, the temperature is raised to 80 ° C. in 50 minutes, and then maintained at 80 ° C. for 30 minutes, and the resin content is flowed to the outer peripheral side by centrifugal force accompanying rotation while maintaining the fluidity of the resin. Yes. Thereafter, the temperature is raised to 130 ° C. over 30 minutes, and the preform 20 is heated stepwise to adjust the resin amount and cure the resin. After the temperature is raised to 130 ° C., the temperature is gradually lowered and the rotation is stopped simultaneously with the temperature fall.

With the heating and rotation described above, the resin content after the rotation control process is increased to 180% with respect to the resin content before the rotation control process in the region from the outer surface to 20% in the radial direction. And after the rotation control process, the resin content of the fiber reinforced resin from the outer surface to the region of 10% of the thickness is set to 65%.
After cooling to room temperature, the polypropylene tape is peeled off from the heat-cured tubular body. Thereafter, as shown in FIGS. 5A and 5B, the cured tubular body 20 ′ is extracted from the mandrel 10, and the outer surface of the tubular body 20 ′ is polished in a polishing process.
In the present embodiment, the tubular body 30 is manufactured by uniformly polishing the outer peripheral surface having a high resin content in the range from the outer surface 20c ′ to the position of 0.06 mm over the entire surface.
During the polishing, the resin component 21 is mainly removed and the fiber component 22 is hardly scraped.
The tubular body may be extracted from the mandrel after polishing, or may be coated for decoration or the like after polishing.

  In this way, by rotating the preform 20 with a uniform resin content while heating as described above, the void is not filled with the resin by flowing the resin component to the outer peripheral side by centrifugal force. In addition, the resin in the resin reservoir portion also flows toward the outer peripheral side, so that the resin content can be made uniform in the circumferential direction. In the radial direction, the resin content can be gradually increased from the inner peripheral side toward the outer peripheral side. And the lightweight and highly rigid tubular body 30 can be easily obtained by grind | polishing after hardening the outer peripheral part which made resin content high.

  In FIG. 6, the tubular body of the present invention is used as a shaft 31 for a golf club. A head 32 is attached to the small diameter end side of the shaft 31, and a grip 33 is attached to the large diameter end side.

  Hereinafter, the Example of the manufacturing method of the tubular body of this invention and a comparative example are explained in full detail.

(Example 1)
A tubular body was manufactured by adjusting the resin content of the preform by the same method as in the above embodiment.

(Comparative Example 1)
Without rotating the mandrel and the preform, the mandrel and the preform were heated and cured with the prepreg laminated. Others were the same as in Example 1.

The prepregs 11, 12, and 14 used MR350C 125S (manufactured by Mitsubishi Rayon), and the prepreg 13 used 8255S-12 (manufactured by Toray).
After heat curing, the thickness of the tubular body before polishing is constant, 3.0 mm, the outer diameter on the small diameter side is 9.5 mm, the outer diameter on the large diameter side is 16.0 mm, and from the outer peripheral surface to the position of 0.06 mm Was polished over the entire outer peripheral surface.

Measure the resin content in the radial direction from the outer peripheral surface of the preform and measure the resin content at a position separated by 20% of the thickness of the preform and at a distance of 10%, and compare before and after molding The results are shown in Table 1.
Further, the distance from the outer peripheral surface to the outermost fiber was measured, and the average value from the small diameter side to the large diameter side of the tubular body was described in the column of “Distance” in Table 1.

(Measurement of 3-point bending strength)
The three-point bending strength of the polished tubular body was measured. The three-point bending strength is an SG type breaking strength determined by the Product Safety Association. As shown in FIG. 7, the tubular body 40 was supported at three points, a load F was applied from above by a load indenter 41, and a load value (peak value) when the tubular body 40 was broken was measured. The measurement points were 90 mm (point T), 175 mm (point A), and 525 mm (point B) from the small diameter end of the tubular body 40 at four positions 175 mm (point C) from the large diameter end. . The span of the two support points 42 was 150 mm only when measuring the T point, and 300 mm when measuring the points A to C. The tip radius of the load indenter 41 was 75 mm, the tip radius of the support point 42 was 12.5 mm, and the load indenter 41 applied a load F to the tubular body 40 at the center position of the support point 42.

Example 1
T point: 205N, A point: 87N, B point: 108N, C point: 122N.
Comparative Example 1
T point: 181N, A point: 75N, B point: 93N, C point: 101N.

Moreover, the cross-section observation of the tubular body after heat-hardening was performed. The resin content was measured by the area ratio of the resin content and the fiber content in the cross section.
In Example 1, the average value of the resin content in the outer half of the cross section was 35% by weight, and the average of the resin content in the inner half was 5% by weight.
In Comparative Example 1, both of the average values of the resin content in the outer peripheral side half and the inner peripheral side half of the cross section were 20% by weight.

  As shown in Table 1 and the experimental results, in Example 1, since the resin content was controlled, the resin content on the outer peripheral side was increased, and the distance from the outer peripheral surface to the outermost fiber was 0.05 mm. Thus, it was confirmed that even if polishing was performed, the fiber was hardly polished, and the rigidity and strength were not reduced by polishing.

  On the other hand, since the comparative example 1 is heat-cured with the prepreg wound, the resin content in the tubular body is constant, and the distance from the outer peripheral surface to the outermost fiber is 0.005 mm. It was confirmed that the fiber portion was polished by polishing, and the rigidity and strength were reduced by polishing.

(A) (B) is the schematic of the mandrel and prepreg which were used for the manufacturing method of the tubular body of this invention. (A) is schematic explanatory drawing of the presence condition of the resin part and fiber part in a preform before resin content rate adjustment, (B) is sectional drawing of a mandrel and a preform. It is explanatory drawing of the rotation state of a mandrel and a preforming body. It is a schematic explanatory drawing of the presence condition of the resin part and fiber part in the preforming body after resin content rate adjustment. (A) shows the tubular body and mandrel after molding, and (B) is a schematic explanatory view of the polishing state of the tubular body. It is the schematic of the golf club shaft using a tubular body. It is explanatory drawing of the measuring method of 3 point | piece bending strength.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 Mandrel 11-14 Prepreg 20 Preformed body 21 Resin content 22 Fiber content 30 Tubular body

Claims (7)

Forming a tubular preform by laminating a fiber reinforced resin layer composed of reinforced fibers and a thermosetting resin;
The preform is rotated while being heated below the curing temperature of the thermosetting resin, and the resin in the preform is caused to flow radially outward by centrifugal force so that the resin in the preform is filled. A rotation control step for controlling the outer surface side resin content to be increased while filling the voids not filled with resin;
A curing step in which the preform with the resin content controlled is heated at or above the curing temperature of the thermosetting resin during or after the rotation to obtain a tubular body;
A polishing step for polishing the outer surface of the tubular body having a high resin content;
The manufacturing method of the tubular body containing this.   The preform is formed by winding a plurality of layers of a prepreg in which a mandrel is impregnated with a thermosetting resin in a reinforcing fiber, and then rotating the mandrel so that the resin content is directed from the inner peripheral side to the outer peripheral side. The manufacturing method of the tubular body of Claim 1 which is made to increase gradually.   The tubular body manufacturing method according to claim 2, wherein the plurality of prepregs have the same resin content.   In the thickness portion from the outer surface to 20% of the entire thickness of the tubular body before the polishing step, the resin content after the rotation control step is 120% to 200% with respect to the resin content before the rotation control step. The manufacturing method of the tubular body of any one of Claim 1 thru | or 3 currently controlled to become%.   The preform is formed in a tapered shape with one end in the axial direction having a small diameter and the other end having a large diameter, and in the preform after the rotation control step, the large diameter side has a higher resin content in the outer peripheral portion than the small diameter side. The manufacturing method of the tubular body of any one of Claim 1 thru | or 4.   A tubular body manufactured by the method for manufacturing a tubular body according to any one of claims 1 to 5.   The tubular body according to claim 6, which is used as a golf club shaft.

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