JP2002283468A - Fiber-reinforced pipe and its production method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To easily provide an FRP pipe which has a low void ratio and good flexural strength characteristics in spite of its high volume ratio of fibers. SOLUTION: In the pipe comprising a plurality of fiber-reinforced resin layers, the volume ratio of fibers of at least one layer is 70-82 vol.%. The void ratio of the pipe is 2 vol.% or below.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a tubular body made of fiber-reinforced resin (hereinafter referred to as FRP) used for fishing rods, shafts for golf clubs, ski poles, tennis rackets, ski poles, bicycle frames and the like, and a method for producing the same. About.

[0002]

2. Description of the Related Art Since fishing rods, golf club shafts, tennis rackets, etc. are required to be lightweight and have high strength and high rigidity, FRPs, particularly carbon fiber reinforced resins (hereinafter referred to as CFRPs), are widely used. Particularly, in recent years, products using CFRP having a higher fiber volume content have been marketed in order to further reduce the weight. A laminate having a content of about 73 to 86%) has been devised.

Generally, an FRP tubular body having a high fiber volume content of 60% by volume or more is formed by laminating or winding a prepreg having a low resin content (a sheet-like intermediate material in which a reinforcing fiber is impregnated in a resin in advance). Thus, it is manufactured under predetermined molding conditions. This is because the fiber volume content cannot be increased if it is produced without a prepreg, and it is difficult to keep the fiber volume content constant. For this reason, at present, prepregs having a resin mass content of about 20 to 55% have been commercially available.

However, when manufacturing a FRP tubular body using a prepreg having an extremely low resin content of about 20% by mass, workability is poor due to low adhesiveness of the prepreg. Since voids remain in the tubular body, bending strength is reduced and peeling is likely to occur.

For this reason, Japanese Patent Application Laid-Open No. 8-207166 discloses a prepreg having a region with a small amount of resin and a region with a large amount of resin in the thickness direction and having an average resin impregnation amount of 10 to 20% by mass. The method of manufacturing the FRP tubular body used was
Japanese Patent Application Laid-Open No. 9-2014434 discloses that the fiber content is 70%.
Disclosed is a method for producing an FRP tubular body in which a thinner prepreg having a fiber content of less than 70% by volume is sandwiched between two prepregs having a volume percentage of not less than 70% by volume and wound around a core for molding. Improvements in wrapping techniques by manufacturers have overcome the poor workability of prepregs with low resin content.

On the other hand, for the purpose of preventing separation between FRP layers, Japanese Patent Application Laid-Open No. 10-694 discloses an oblique fiber main body layer in which the fiber direction is oriented in an inclined direction and an axis in which the fiber direction is oriented in an axial direction. While winding a prepreg in which the resin impregnation amount of the long fiber main body layer is approximately 10% by mass or more and less than 25% by mass,
Characterized in that a thin thick layer having a high resin content is formed between the skewed fiber main body layer and the axial long fiber main body layer,
An FRP tubular body is disclosed. However, when a prepreg having a high resin content is used in combination, a problem arises in that the weight of the FRP tubular body increases. Further, when molding a FRP tubular body using a prepreg having a low resin content, not only voids at the lamination interface generated due to low adhesiveness,
Regarding voids caused by insufficient resin impregnation of the reinforcing fibers in the prepreg due to extremely low resin content, when a prepreg having a high resin content is used in combination, there is a problem that the voids are hardly removed. .

Further, Japanese Patent Application Laid-Open No. 10-67054 discloses that the first prepreg having a resin content of 10 to 20% by mass (the fiber direction is the longitudinal direction of the tubular body) has a maximum of two continuous windings. An FRP tubular body characterized by being divided is disclosed. Shortening the number of continuous windings to two or less may reduce the occurrence of voids,
There is a concern that the strength may be reduced due to an increase in the number of discontinuous layers, while there is a problem that the production becomes complicated.

[0008]

SUMMARY OF THE INVENTION The present invention solves the problem that it is difficult to obtain a high bending strength in an FRP tubular body including a layer having a high fiber content as described above.
An object of the present invention is to provide an FRP tubular body having improved strength and a method for producing the same.

[0009]

A first gist of the present invention is as follows.
In a tubular body having a plurality of FRP layers formed, at least one of the layers has a fiber volume content of 70 to 82% by volume.
And the void ratio is 2% by volume or less.

[0010] A second gist of the present invention is that a plurality of FRP intermediate material layers are formed on a cored bar, a resin film is wound thereon at a constant pitch, fixed, heated and cured. In the method for producing a tubular body made of FRP,
The fiber content of at least one of the FRP intermediate material layers is 70
~ 82% by volume, and a method for manufacturing an FRP tubular body characterized by winding a resin film twice or more.

[0011]

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, the present invention will be described in detail together with preferred embodiments of the present invention.

The tubular body made of FRP according to the present invention is made of FRP.
The layers are laminated, and at least one layer has a fiber volume content of 70 to 82% by volume, and the high fiber content layer has a void fraction of 2% by volume or less, more preferably 1% by volume or less. The void ratio here is defined by the fiber content of the carbon fiber reinforced plastic specified in JIS K 7075 and the void ratio obtained by the void ratio measurement method. In an FRP tubular body having a void ratio of more than 2% by volume, the bending strength does not increase, and the strength varies depending on the measurement position.

The reinforcing fibers used in the present invention include carbon fibers, glass fibers, boron fibers, silicon carbide fibers, alumina fibers, aramid fibers, polyphenylene benzobisoxazole fibers and the like.
It is most suitable because it has excellent specific rigidity.

The matrix resin constituting the FRP layer is not particularly limited, but a thermosetting resin or a thermoplastic resin such as an epoxy resin, an unsaturated polyester resin, a vinyl ester resin, a polyimide resin, and a polybismaleimide resin may be used. Can be. Among them, epoxy resins are most preferred from the viewpoints of adhesion to reinforcing fibers, strength development, cure shrinkage, moisture resistance, and weather resistance.

The high fiber content layer having a fiber volume content of 70 to 82% by volume has at least one layer in order to reduce the weight of the obtained tubular body. More preferably, at least half of the number of FRP layers constituting the high fiber content layer is high fiber. Further weight reduction can be achieved by using the containing layer. The orientation angle of the reinforcing fibers in the high fiber content layer can be from 0 ° (that is, parallel to the axial direction) to 90 ° with respect to the axial direction (longitudinal direction) of the tubular body. When 0 is set to 0 ° or 45 °, the ratio in increasing the bending strength, bending stiffness, torsional strength, and torsional stiffness in the axial direction increases, so that such FRP
When the layer is a high fiber content layer, the contribution to weight reduction of the FRP tubular body increases.

Next, a method for producing the FRP tubular body of the present invention will be described. In the present invention, the FRP tubular body is formed by winding an FRP intermediate material layer on a cored bar, and fixing and winding a resin film thereon at a constant pitch, and after heating and curing, removing the resin film. In the method for producing an FRP tubular body, at least one layer of the FRP intermediate material layer has a fiber content of 70 to 82% by volume, and is produced by winding the resin film twice or more.

The fiber-reinforced resin intermediate material to be used is a sheet-like product in which a matrix resin (precured in the case of a thermosetting resin) is impregnated in advance with a reinforcing fiber generally called a prepreg, and at least one layer is a fiber-containing product. Rate 70
８２82% by volume (the prepreg used is a carbon fiber reinforced epoxy resin intermediate material and the density of carbon fibers is 1.8 g / cm ³ ,
If the density of the epoxy resin is 1.2 g / cm ³ , the resin content is about 22.5 to 13% by mass). The thickness of the prepreg to be used is not particularly limited.
Those having a thickness of 200 μm are preferably used.

The resin film has a width of 10 to 30 mm and a thickness of 10 to 40 μm, more preferably 20 to 30 μm.
Although it is a resin film of μm and the material is not particularly limited, polypropylene and polyethylene terephthalate are preferable in terms of heat resistance, strength, and releasability from the molded FRP tubular body. Further, stretched polypropylene and polyethylene terephthalate are more preferable in terms of strength and heat shrinkage. The winding pitch of the resin film is preferably in the range of 1 to 3 mm. By winding twice or more, even if the fiber content is 70 to 82% by volume.
It is possible to form an FRP tubular body having a void ratio of 2% or less even if the above layer is included. The method of winding the resin film into two or more layers is not particularly limited, and a method of winding the resin film once wound on the same operation once again or a mechanism having two unwinding of the resin film may be employed. A method of using the apparatus to perform double winding during one scan is illustrated.

The tension per tape width around which the resin film is wound is preferably 20 to 60 N / cm, more preferably 25 to 50 N / cm. If the tension is less than 20 N / cm, voids are generated in the high fiber content layer, which is not preferable. If the tension is more than 60 N / cm, the resin film may be broken by the tension, which is not preferable.

[0020]

The present invention will be specifically described below with reference to examples. The following prepreg, cored bar, and resin film were used in manufacturing an FRP tubular body (golf club shaft). [Prepreg] As prepreg, commercially available MR350B
100S (Mitsubishi Rayon Co., Ltd., basis weight 125g /
m ² , resin content 20% by mass). The carbon fiber used in this prepreg was MR40 (manufactured by Mitsubishi Rayon Co., Ltd., elastic modulus 294 GPa, density 1.77).
g / cm ³ ), and the matrix resin is epoxy resin # 350 (manufactured by Mitsubishi Rayon Co., Ltd., density 1.20 g).
/ Cm ³ ). [Core metal] As a core metal for producing a tubular body, the outer diameter Da at the distal end on the smaller diameter side is 5.0 mm, the outer diameter Db at a position 1000 mm from the distal end on the smaller diameter side is 13.5 mm, and the outer diameter Db is 1000 from the distal end on the smaller diameter side.
In FIG. 1, 500 mm from the position of mm to the tip of the large diameter side is a parallel portion, and the outer diameter Dc of the tip of the large diameter side is 13.5 mm.
A core metal having a total length of 1500 mm shown in (a) was used. [Resin Film] A commercially available 20 mm wide, 30 μm thick polypropylene tape (trade name: Mirefan, Mitsubishi Rayon Co., Ltd.) as a resin film used for forming a tubular body
Manufactured).

(Embodiment) 7 from the tip of the small diameter side of the mandrel
Wrapped portion from the position _{P 1} of 5mm up to the position _{P 2} of 1240mm from the small-diameter side distal end becomes a three-layer over _{P 2} from _{P 1,} and the + 45 ° direction of the carbon fibers relative to the metal core axis Prepreg MR350B
100S is a substantially trapezoid having a length of 1165 mm (FIG. 1).
(Shown in (b)). The next time likewise wrapped becomes P ₂ over by three layers from P _1, and, as in the direction of the carbon fiber is -45 ° with respect to the metal core axis was cut the same prepreg (Figure 1 (Shown in (c)). Then, after bonding these two prepregs, winding them around the core metal, FRP of ± 45 ° with respect to the axial direction.
A layer (hereinafter, referred to as an angle layer) was formed. FIG.
In (b) and (c), L = 1165 mm, L ₁ = 56 m
m, L ₂ = 130 mm, L ₃ = 240 mm, and the arrows indicate the orientation angles of the carbon fibers.

Next, when wound on the angle layer,
From P ₁ becomes _{P 2} over to four layers, and carbon fiber with respect to the metal core axis direction is cut out prepreg MR350B100S in parallel (0 °) (FIG. 1 (d)). Then, this was wound on a winding layer for an angle layer to form an FRP layer (hereinafter, referred to as a straight layer). In addition, in FIG. 1D, L = 1165 mm, L ₄
= 85 mm, L ₅ = 184 mm, L ₃ = 240 mm, and the arrows indicate the orientation angles of the carbon fibers.

Next, when the wound on the straight layer, the _{P 1} and _{P 1} to the position of 150mm becomes a three-layer, and then layer wound toward the _{P 2} decreases P
_A prepreg MR350B for a tip reinforcing layer so that it is no longer at a position of ₁ to 300 mm and the carbon fiber is at 0 °.
100S was cut out (shown in FIG. 1 (e)). And
This from _{P 1} on the straight layer 300 in the _{P 2} direction
The FRP layer (hereinafter, referred to as a tip reinforcing layer) was formed by wrapping around a part up to mm. Subsequently, the prepreg MR350B100S for adjusting the outer diameter on the small diameter side is shown in FIG.
Cut into square, wound on site from _{P 1,} to 100mm in _{P 2} direction. In FIGS. 1 (e) and 1 (f),
L ₆ = 69 mm, L ₇ = 81 mm, L ₈ = 300 mm,
L ₉ = 150 mm, L ₁₀ = 135 mm, L ₁₁ = 10
0 mm, and the arrow indicates the orientation angle of the carbon fiber.

Next, about the resin film from the position of _{P 2} 3
A tension of 50N (25N /
cm width) wound toward the _{P 1} while feeding at a 2.5mm pitch / rotated downward, beyond the _{P 1,} about 3 from the position of _{P 1}
Wrap it to the position of the small diameter side of the 0 mm core bar, stop it with a commercially available adhesive tape (Nitto Denko Packaging System Co., Ltd., cellophane tape) so that the resin tape does not come off, then cut the resin tape to single Eye winding was applied. Further, after the first winding, the second winding was performed by applying the same winding conditions and the same procedure as the first winding.

Next, this was cured by heating at 135 ° C. for 2 hours, and then the mandrel was de-centered to peel off the double resin film. Cut both ends about 10mm each, mass about 57
g, a length of 1145 mm, a tip diameter on the small diameter side of about 8.5 mm, and a golf club shaft having a tip diameter on the large diameter side of about 15.0 mm. Five of the obtained shafts were JIS K7
Among the methods for measuring the fiber content and porosity of the carbon fiber reinforced plastic specified in 075, the fiber volume content and the porosity (void rate) were determined by the sulfuric acid decomposition method. The average fiber volume content was 73.4% by volume, and the void ratio (void ratio) was 0.8%.

The three-point bending strength of the shaft is determined by a certification standard for golf club shafts and a method for confirming the standards (commonly approved by the Minister of Industry, No. 5, No. 2087, October 1993).
4), a position 175 mm from the small-diameter end (so-called point A), a position 525 mm from the small-diameter end (so-called point B), and a position 175 mm from the large-diameter end (so-called point C). The measurement was performed according to the measurement method. The number of measurement was 25, and the average value was calculated according to JISZ8401.
The coefficient of variation was calculated. Average flexural strength at point A is 957N
(The lowest value among the 25 measurements was 870 N, the coefficient of variation was 4.2%), and the average bending strength at point B was 928 N (minimum value 8
56N, coefficient of variation was 4.6%), and the average bending strength at point C was 1110N (minimum value: 991N, coefficient of variation was 4.8%).

(Comparative Example) Winding was performed using the same core metal, prepreg, and pattern as in the example. For the winding of the resin film, the same resin film as in the example was used, and a single winding was performed with the same tension and pitch as in the example. Next, the same heat curing as in the example with only a single winding,
De-center, cut both ends, mass 57g, length 1145m
m, about 8.5 mm on the small diameter side, about 15.5 mm on the large diameter side.
A 0 mm golf club shaft was obtained. The fiber volume content of the five obtained shafts was 73.2%, and the void ratio was 3.1%. The bending strength of the obtained shaft was measured in the same manner as in the Example. The average bending strength at point A is 894N (the lowest value of the 25 measurements is 767N,
The coefficient of variation is 5.5%) and the average bending strength at point B is 878N.
(Minimum value: 760 N, coefficient of variation: 5.7%), and the average bending strength at point C was 1,040 N (minimum value: 870 N, coefficient of variation: 6.2%).

[0028]

[Table 1]

[0029]

According to the present invention, it is possible to easily provide an FRP tubular body having a low fiber content, a low void ratio, and excellent bending strength characteristics. Therefore, the FRP tubular body of the present invention is most suitable for fishing rods, golf club shafts, ski poles, tennis rackets, ski poles, bicycle frames, and the like.

[Brief description of the drawings]

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a view for explaining a wrapping pattern of a prepreg around a core bar in an embodiment, (a) a plan view showing a core bar, (b) a plan view of a prepreg for an angle layer, and (c).
FIG. 2 is a plan view of a prepreg for an angle layer, (d) a plan view of a prepreg for a straight layer, (e) a plan view of a prepreg for a tip reinforcing layer, and (f) a plan view of a prepreg for adjusting a small-diameter side outer diameter.

Continued on front page F-term (reference) 2B019 AB03 AB04 AB14 AB22 2C002 AA05 CS03 MM02 PP01 4F205 AD16 AD19 AG08 AH59 HA02 HA23 HA33 HA35 HA45 HB01 HC17 HL11 HT13 HT20 HT22

Claims (7)

[Claims] 1. A tubular body comprising a plurality of fiber-reinforced resin layers, wherein at least one layer has a fiber volume content of 70 to 82.
A fiber-reinforced resin tubular body having a volume percentage of 2% by volume or less. 2. The fiber-reinforced resin tubular body according to claim 1, wherein the reinforcing fibers constituting the fiber-reinforced resin layer are carbon fibers. 3. The fiber-reinforced resin tubular body according to claim 1, wherein the reinforcing fibers in the high fiber content layer are oriented at 0 to 90 ° with respect to the tubular body axial direction. 4. A fiber reinforced resin comprising a plurality of fiber reinforced resin intermediate material layers formed on a cored bar, a resin film wound thereon at a constant pitch, fixed, heated and cured, and then the resin film is removed. In the method for producing a tubular body, at least one of the fiber-reinforced resin intermediate material layers has a fiber content of 70%.
A method for producing a fiber-reinforced resin tubular body, which comprises winding a resin film twice or more. 5. The winding tension of the resin film is 20-6.
The method for producing a fiber-reinforced resin tubular body according to claim 4, wherein the pressure is 0 N / cm. 6. The method for producing a fiber-reinforced resin tubular body according to claim 4, wherein the resin film is made of polypropylene or polyethylene terephthalate. 7. The method for producing a fiber-reinforced resin tubular body according to claim 4, wherein the reinforcing fibers constituting the fiber-reinforced resin intermediate material are carbon fibers.