JPH07165950A - Prepreg sheet and fiber-reinforced resin tubular form - Google Patents

Abstract

PURPOSE:To obtain a lightweight prepreg with natural fibers as reinforcing material, having practically sufficient mechanical strength and modulus, excellent in impact resistance and vibration damping, moldable into thin-walled or small- diameter tubular forms, and high in producibility. CONSTITUTION:Firstly, an epoxy resin composition is prepared by incorporating Japanese paper with 30 pts.wt. of a bisphenol A-type epoxy resin, 70 pts.wt. of bisphenol F-type epoxy resin, 4 pts.wt. of dicyanamide (DICY) as a curing agent and 4 pts.wt. of dichlorophenyl dimethylurea (DCMU) as an accelerator. Next, a mold releasing paper is coated with this composition followed by laminating with paper and then hot contact bonding with a press roller to effect impregnating the Japanese paper with the resin composition, thus the aimed prepreg is obtained.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a prepreg sheet and a fiber-reinforced resin tubular body made of paper made of plant fiber as a reinforcing material.

[0002]

2. Description of the Related Art In recent years, high-performance fibers such as carbon fibers, aramid fibers or boron fibers have been developed as fibers used in fiber reinforced resins. Since so-called advanced composite materials using these as reinforcing fibers have high strength and high elastic modulus and are lightweight, they are widely used as substitutes for metals from the aerospace field to the sports field.

[0003]

However, although the advanced composite material has very high strength and elastic modulus, it generally has low performance such as impact resistance and vibration damping. Furthermore, it is extremely difficult to dispose of these high-performance fibers and advanced composite materials, which has become a major environmental problem.

On the other hand, natural fibers have been conventionally used as reinforcing fibers for fiber-reinforced resins. Contrary to advanced composite materials, natural fiber reinforced resins have low strength and elastic modulus, but relatively high impact resistance (for example, Takeshi Hayashi,
"Composite Material Engineering", P78, JST, 1971). Also, since natural fibers are decomposed in the natural world and natural fiber reinforced resins can be incinerated relatively easily, it can be said that they are environmentally friendly materials compared to high performance fibers and advanced composite materials.

As an example of the natural fiber reinforced resin, there is a golf head in which a matrix resin is mixed with a natural fiber and transfer molding is performed (eg, Nikkei New Material, P6).
0, Nikkei McGraw-Hill, December 24, 1990). Also,
Japanese Unexamined Patent Publication No. 4-175347 proposes a method of mixing a kozo fiber with a thermosetting resin, setting this in a mold, and curing and releasing the mold to take out a molded product. As described above, the method of mixing short fibers with a matrix resin and molding is relatively easy and has high productivity, but on the other hand, it is difficult to increase the fiber content and the fiber orientation, and the mechanical properties of the fibers are sufficient. There is a problem that can not be fully utilized.

Japanese Unexamined Patent Publication Nos. 5-155374 and 5
In Japanese Patent Laid-Open No. 157184/1993, Japanese paper made of natural fibers is cut into strips and appropriately twisted to make a paper thread, which is used as a reinforcing material, and is made by filament winding (FW) while impregnating this with an epoxy resin. Pipes have been proposed. The use of paper yarn as paper has an advantage in that the density of the fibers and the entanglement of the fibers are increased and the strength is increased as compared with the sheet-shaped paper.

On the other hand, in the FW method, since it is difficult to make the winding angle of the reinforcing material parallel to the longitudinal direction of the tubular body, it is disadvantageous when considering the strength and elastic modulus in the longitudinal direction. Also, FW
The method has a drawback in that stress is likely to be concentrated on the bent portion because the method produces a crossing portion of the yarn. Further, in the FW method, it is difficult to wind the yarn without a gap, and the gap generated at the crossing portion is included.
There is a lot of room for resin to enter, and the fiber content tends to decrease.

From the viewpoint of moldability, the FW method is not suitable for molding thin or thin tubular bodies. From the viewpoint of productivity, there is a problem that the paper thread manufacturing process is added to the ordinary papermaking process and the FW method has lower productivity than the sheet winding method.

A method in which a paper thread is made into a woven fabric, which is prepregized and formed into a tubular body by a sheet winding method is also considered. However, the woven fabric has problems that crimp occurs and stress concentrates easily on the crimp, and productivity is low.

As described above, the conventional fiber reinforced resin using natural fibers as a reinforcing material has not been sufficiently satisfactory in terms of the balance of mechanical properties, moldability and productivity. Therefore, the object of the present invention is to 1) use natural fiber as a reinforcing material, be lightweight, have practically sufficient strength and elastic modulus, and be excellent in impact resistance and vibration damping property 2) Thin or thin tubular It is an object of the present invention to provide a prepreg sheet capable of molding a body and satisfying high productivity and a fiber-reinforced resin tubular body molded from the prepreg.

[0011]

Means for Solving the Problems The present inventor satisfies the above-mentioned object by using a specific vegetable fiber as a main component to obtain a paper having excellent mechanical properties, and using the paper in a sheet form. The inventors have found that a prepreg and a fiber-reinforced resin tubular body can be obtained, and completed the present invention.

That is, a prepreg sheet obtained by impregnating a Japanese resin containing at least one of bast fibers and vein fibers as a main component with a matrix resin, and a fiber-reinforced resin tubular body formed by winding the prepreg sheet around a core and forming a tubular shape. Is.

The bast fibers used in the present invention are classified into woody bast fibers such as 杮, 椏, goose bark, mulberry and salago, and herbaceous bast fibers such as cannabis, flax, ramie, jute and kenaf. The vein fibers include Manila hemp, sisal hemp, banana and pineapple fiber. These fibers have a high specific strength and a large aspect ratio.

The main raw material of the Japanese paper used as the reinforcing material of the prepreg of the present invention is pulped plant fiber, but when it is used as the reinforcing material of the composite material, 1) the strength of the Japanese paper, 2) the impregnation property of the resin (fiber) And the affinity with the resin) are important.

Furthermore, there are three factors of the strength of Japanese paper: 1) the strength of the fibers themselves, 2) the adhesive strength between the fibers, and 3) the friction due to the entanglement of the fibers, but among them, the bast fibers and the vein fibers are for the following reasons. Chosen from among.

The interfiber adhesion of paper fibers is due to hydrogen bonding of cellulose, which is a constituent of the fibers. Therefore, a fiber containing a large amount of cellulose having a high hydrogen bonding property is desirable. However, linters (fluff fibers) are not suitable because they often contain α-cellulose (having high crystallinity and low hydrogen bondability) and low interfiber bonding strength. (The following table shows the α-cellulose content in the holocellulose of the raw material fibers for paper.) Bast fiber Leaf vein fiber Wood fiber Linter Holocellulose (%) 50-72 65.9 77.1 82.5 α-cellulose (%) 43-56 53- 64 42.5 82.5 Since bast fibers and vein fibers have many fibers of relatively round cross section and are long, a porous structure can be obtained. Therefore, the impregnation property of the matrix resin is good. On the other hand, since the wood pulp fibers used in the paper have a flat cross section and a dense structure, the impregnability of the matrix resin is poor. (The density of paper at the same beating degree is shown in the table below.) Bast fiber (Sanhime) Leaf vein fiber (Manila hemp) Wood fiber (NBKB) Density (g / cm ² ) 0.662 0.641 0.865 Wood property among Japanese paper fibers Bast fibers such as swordfish, goose bark, mulberry and salago have many soft cells, and have high interfiber adhesiveness, and since the fibers are thin and long, it is possible to obtain high-strength washi paper.楮 三 椏 薮 皮 Mulberry average fiber length (mm) 6 to 21 3 to 5 3 to 5 6.97 2.97 average fiber width (μm) 10 to 30 10 to 30 10 to 30 17 12 Among the Japanese paper fibers, it is a herbaceous bast fiber. Cannabis, flax and kenaf have long fibers and high strength.

Cannabis Flax Ginseng Burlap Average fiber length (mm) 25 20-30 20-200 20-30 Average fiber width (μm) 15-25 10-30 24-47 20-25 Single fiber strength (10 ³ N / cm ² ) 70 76 to 88 91 85 Manila hemp, sisal, banana and pineapple fibers, which are vein fibers among the fibers for Japanese paper, are not as thick as bast fibers, but the fibers are relatively thin and long. The strength of this fiber can be adjusted by fibrillation by beating like wood pulp (NBKP, LBKP) which is a raw material for western paper.

Manila hemp Sisal banana Pineapple fiber Average fiber length (mm) 2 to 12 0.8 to 8.0 3.5 to 4.7 (3 to 9) Average fiber width (μm) 16 to 328 to 41 to 27 to 31 (5 to 10) In addition, a small amount of wood pulp or synthetic fiber which does not deteriorate the properties of Japanese paper can be mixed and used.

(Pipe-formed) main bast fibers are produced by steaming bark stripped from the above-mentioned original with a chemical such as an alkali to produce fibers for Japanese paper. On the other hand, the herbaceous bast fiber is produced by separating a fiber bundle from its stem by a method such as fermentation and then steaming it with a chemical solution such as an alkali to produce a fiber for Japanese paper. In addition, leaf vein fibers are produced by removing the mesophyll from the leaves and steaming the remaining leaf veins with a chemical such as an alkali to produce fibers for Japanese paper.

The pulping conditions of San Tsubaki and Manila hemp, which are typical fibers of machine-made Japanese paper, will be described below. (Three tsubaki pulp) After air-dried white skin three tsubaki is soaked in one liquid water, it is put into a flat kettle, and 15% caustic soda and 15 times water of three tsubaki are added and heated for 1.5 hours. This is drained and washed with water,
After being dispersed in a beater, it is bleached with sodium hypochlorite, washed with water and then dedusted and dehydrated to obtain a wet pulp sheet.

(Manila hemp pulp) Manila hemp is charged into a spherical digester and caustic soda of 15% of the weight of the Manila hemp and 3 to 3 are added.
Add 4 times water and steam heat for 6 hours at a steam pressure of 5.5 kg / cm ² . This is dewatered, washed with water, dispersed with a beater, bleached with sodium hypochlorite, further washed with water to remove dust and dehydrate to obtain a wet pulp sheet.

(Adjustment) It is the papermaking process that determines the uniformity, strength characteristics and anisotropy of Japanese paper, but the handmade method, which has been handed down since ancient times, cannot provide a continuously uniform Japanese paper. Therefore, the machine papermaking method is used, but in that case 25 mm
The above extremely long fibers are not suitable because they tend to bind due to entanglement during the process.

Therefore, fibers are fibrillated by a disperser / beater such as a beater, cut into fibers, or a plurality of different types of pulp are mixed to prepare a raw material system that facilitates papermaking. (Papermaking) Machine As the papermaking machine, each papermaking machine such as a long-mesh, a short-mesh, a slanted wire, a cylinder, and a rotoformer, which are also used in the production of paper, is appropriately used. Above all, with a cylinder paper machine, the fibers are oriented in the MD direction, and it is possible to produce a highly anisotropic Japanese paper. Further, with a slanted wire or rotoformer, the fiber orientation can be arbitrarily set, and Japanese paper having an arbitrary strength ratio can be produced.

By using the above paper as a reinforcing material, the strength of the prepreg itself is increased and the workability during molding is stabilized. Further, since the paper used in the present invention has a porous structure, it easily becomes a prepreg having a good resin impregnation property, and defects such as voids are less likely to occur in the molded product.

The fiber-reinforced resin molded from this prepreg has practically sufficient strength and elastic modulus. Above all, more preferable results can be obtained by using paper having anisotropy as the reinforcing material. This is because giving the paper anisotropy enhances the orientation of the fibers constituting the paper, and as a result, the strength and elastic modulus of the paper in the fiber orientation direction increase. In particular, it is preferable to use paper having a tensile strength of 1400 kgf / cm ² or more and a tensile modulus of 1000 kgf / mm ² or more in order to enhance the mechanical properties of the fiber-reinforced resin.

The prepreg treatment of paper can be performed by a conventionally known wet method (solvent method) or dry method (hot melt method). The wet method is a method of dissolving a matrix resin, a curing agent, a catalyst and the like in an appropriate solvent to prepare a solution, impregnating this with a reinforcing material, and then heating to remove the solvent. The dry method is a method in which a resin, a curing agent, and the like are heated and melted, and a resin in a molten state is impregnated into a reinforcing material and cooled. Here, the matrix resin is a thermosetting resin such as an epoxy resin, a phenol resin, or a bismaleimide resin, or a thermoplastic resin such as polyamide, polyolefin, polyester, or polycarbonate, depending on the purpose of mechanical properties, heat resistance, workability, etc. An appropriate resin may be used among the resins.

Of these, epoxy resin is an example in which particularly preferable results are obtained. The resins include epibis type, phenol novolac type, Brized epibis type, TGDDM.
(Tetraglycidylaminodiphenylmethane), TGM
AP (triglycidylmethaaminophenol) and the like are used as hardeners such as BF3.MEA (boron trifluoride monoethylamine), DICY (dicyandiamide), DC.
MU (dichlorophenyldimethylurea), imidazole, DDS (diaminodiphenyl sulfone), DDM
(Diaminodiphenylmethane) and the like are widely used.

In particular, in the case of 250 ° F. curing type, epibis type and novolac type epoxy resin is mainly used, DICY is often used as the curing agent, and DCMU is often used as the accelerator. Also,
In the case of 350 ° F curing type, T which is a tetrafunctional epoxy resin
Main component is GDDM, curing agent is DDS, accelerator is BF3
-Often used in MEA combinations. Here, in order to utilize the color of the colored paper in the molded product, the color of the resin must be taken into consideration. Further, the prepreg sheet can be combined with a scrim cloth or the like within a range that does not impair the object of the present invention.

To form a fiber-reinforced resin tubular body from a prepreg sheet, a sheet winding method (cylindrical winding method) using a rolling machine is generally used.

[0030]

The reason why the prepreg and the fiber-reinforced resin tubular body of the present invention have various excellent properties has not been fully clarified, but is presumed to be based on the following factors.

The paper used in the present invention has high strength, elastic modulus and toughness. This is because the fibers, which are the main components of the paper, have a high specific strength and a high specific elastic modulus, a large aspect ratio, and a strong adhesive strength between the fibers. In particular, anisotropic paper made by orienting fibers has high strength and elastic modulus. Further, by using paper as the reinforcing material, the fiber content rate, orientation, and dispersibility are stabilized, although it is basically a short fiber reinforced resin. Further, since the paper is porous, it has a good impregnation property with the matrix resin and is less likely to cause defects such as voids.

For the above reason, the fiber reinforced resin molded from the prepreg sheet of the present invention, particularly the tubular body, has a reinforcing effect close to that obtained when the continuous fiber is used as the reinforcing material, and is higher than the conventional natural fiber reinforcing material. It has a specific strength and a specific elastic modulus. On the other hand, due to the ductility of the reinforcing paper and fibers, it is superior in impact resistance to CFRP (carbon fiber reinforced resin), GFRP (glass fiber reinforced resin) and the like. Also,
Vibration damping is also large.

Next, from the viewpoint of the molding surface, the prepreg sheet of the present invention can be made thin, which is advantageous for molding a thin tubular body or a thin tubular body. Further, as compared with a tubular body formed by sheet winding or FW of a woven fabric, there are few bent portions in the fiber, and stress concentration is less likely to occur.

[0034]

[Examples] Table 1 shows the physical properties of various papers produced by changing the raw material fibers and the composition. Here, MD is the machine direction and CD is the direction perpendicular to it. Washi Nos. 1 to 5 are the papers used in the examples, and these have high tensile strength and tensile elastic modulus in the fiber orientation direction. Washi Nos. 6 and 7 are the papers used in the comparative examples, and these have low tensile strength and tensile elastic modulus.

[0035]

[Table 1]

Table 2 shows a bisphenol A type epoxy resin (Okaka Shell Epoxy Co., Ltd.) for the paper shown in Table 1.
Made, Epicoat 828) 30 parts by weight, bisphenol A
Type epoxy resin (Okaka Shell Epoxy [Co.], Epicoat 1001) 70 parts by weight, DICY as a curing agent (Okaka Shell Epoxy [Co.], Epicure DICY-7)
4 parts by weight and 4 parts by weight of DCMU as a curing accelerator were mixed to obtain an epoxy resin composition. This resin was applied on a release paper, and the paper and the paper were superposed on each other and heat-pressed with a press roller to impregnate the Japanese paper with the resin to obtain prepregs of Examples 1 to 5 and Comparative Examples 1 and 2.
The properties are shown in Table 2.

The papers used in Comparative Examples 1 and 2 are poor in resin impregnation and have low paper strength, so that the amount of resin is large.

[0038]

[Table 2]

In order to understand the basic mechanical characteristics of the prepreg, a prepreg was formed into a laminated plate by press molding, and a tensile test and a three-point bending test were conducted. The measurement results are shown in Table 3. The measurement is performed according to JIS K 7054 (198).
7) and JIS K 7055 (1987). It can be seen that the laminated plates formed from the prepregs of Examples 1 to 5 have high strength and elastic modulus and can be used for various products. On the other hand, the laminated plates of Comparative Examples 1 and 2 have low strength and elastic modulus and are not suitable for practical use.

[0040]

[Table 3]

Further, the results of examining the impact resistance and vibration damping property of a tubular body formed by winding the above prepreg around a core metal by sheet winding, curing the core and then molding the core body are shown in Table 4.
Shown in. Here, ◯ means good and Δ means bad.

The tubular bodies formed from Examples 1 to 5 of the present invention have good impact resistance and vibration damping properties, and can be applied to various fields such as fishing rods and golf shafts. In addition, thin-walled tubes and thin tubes can be easily formed.

On the other hand, the tubular bodies molded from Comparative Examples 1 and 2 were inferior in impact resistance and vibration damping property, and could not be used for fishing rods, golf shafts and the like.

[0044]

[Table 4]

[0045]

As described in detail above, the present invention has the following excellent effects. 1) Since vegetable fiber is used as a reinforcing material, it is easier to dispose of it than conventional high performance fiber. The fiber-reinforced resin molded from this can be easily incinerated if the composition of the matrix resin is taken into consideration. 2) The tubular body of the present invention is lightweight, has practically sufficient strength and elastic modulus, and is also excellent in impact resistance and vibration damping. 3) In producing the prepreg and the tubular body, a method with high productivity can be adopted. 4) A thin tube or a thin tube can be formed. 5) By coloring the fiber or paper, a quality product different from the conventional surface-coated molded product can be obtained.

─────────────────────────────────────────────────── ───

[Procedure amendment]

[Submission date] June 8, 1994

[Procedure Amendment 1]

[Document name to be amended] Statement

[Correction target item name] Full text

[Correction method] Change

[Correction content]

[Document name] Statement

Title of invention Prepreg sheet and fiber-reinforced resin tubular body

[Claim scope]

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a prepreg sheet and a fiber-reinforced resin tubular body made of Japanese paper made of vegetable fiber as a reinforcing material.

[0002]

2. Description of the Related Art In recent years, high-performance fibers such as carbon fibers, aramid fibers or boron fibers have been developed as fibers used in fiber reinforced resins. Since so-called advanced composite materials using these as reinforcing fibers have high strength and high elastic modulus and are lightweight, they are widely used as substitutes for metals from the aerospace field to the sports field.

[0003]

However, although the advanced composite material has very high strength and elastic modulus, it generally has low performance such as impact resistance and vibration damping. Furthermore, it is extremely difficult to dispose of these high-performance fibers and advanced composite materials, which has become a major environmental problem.

On the other hand, natural fibers have been conventionally used as reinforcing fibers for fiber-reinforced resins. Contrary to advanced composite materials, natural fiber reinforced resins have low strength and elastic modulus, but relatively high impact resistance (for example, Takeshi Hayashi,
"Composite Material Engineering", P78, JST, 1971). Also, since natural fibers are decomposed in the natural world and natural fiber reinforced resins can be incinerated relatively easily, it can be said that they are environmentally friendly materials compared to high performance fibers and advanced composite materials.

As an example of the natural fiber reinforced resin, there is a golf head in which a matrix resin is mixed with a natural fiber and transfer molding is performed (eg, Nikkei New Material, P6).
0, Nikkei McGraw-Hill, December 24, 1990). Also,
Japanese Unexamined Patent Publication No. 4-175347 proposes a method of mixing a kozo fiber with a thermosetting resin, setting this in a mold, and curing and releasing the mold to take out a molded product. As described above, the method of mixing short fibers with a matrix resin and molding is relatively easy and has high productivity, but on the other hand, it is difficult to increase the fiber content and the fiber orientation, and the mechanical properties of the fibers are sufficient. There is a problem that can not be fully utilized.

Japanese Unexamined Patent Publication Nos. 5-155374 and 5
In Japanese Patent Laid-Open No. 157184/1993, Japanese paper made of natural fibers is cut into strips and appropriately twisted to make a paper thread, which is used as a reinforcing material, and is made by filament winding (FW) while impregnating this with an epoxy resin. Pipes have been proposed. The use of Japanese paper as a paper thread has an advantage in that the density of the fibers and the entanglement of the fibers are increased, and the strength is increased, as compared with the sheet-shaped Japanese paper.

On the other hand, in the FW method, since it is difficult to make the winding angle of the reinforcing material parallel to the longitudinal direction of the tubular body, it is disadvantageous when considering the strength and elastic modulus in the longitudinal direction. Also, FW
The method has a drawback in that stress is likely to be concentrated on the bent portion because the method produces a crossing portion of the yarn. Further, in the FW method, it is difficult to wind the yarn without a gap, and the gap generated at the crossing portion is included.
There is a lot of room for resin to enter, and the fiber content tends to decrease.

From the viewpoint of moldability, the FW method is not suitable for molding thin or thin tubular bodies. From the viewpoint of productivity, there is a problem that the paper thread manufacturing process is added to the ordinary papermaking process and the FW method has lower productivity than the sheet winding method.

A method in which a paper thread is made into a woven fabric, which is prepregized and formed into a tubular body by a sheet winding method is also considered. However, the woven fabric has problems that crimp occurs and stress concentrates easily on the crimp, and productivity is low.

As described above, the conventional fiber reinforced resin using natural fibers as a reinforcing material has not been sufficiently satisfactory in terms of the balance of mechanical properties, moldability and productivity. Therefore, the object of the present invention is to 1) use natural fiber as a reinforcing material, be lightweight, have practically sufficient strength and elastic modulus, and be excellent in impact resistance and vibration damping property 2) Thin or thin tubular It is an object of the present invention to provide a prepreg sheet capable of molding a body and satisfying high productivity and a fiber-reinforced resin tubular body molded from the prepreg.

[0011]

The inventor of the present invention satisfies the above-mentioned object by using a specific vegetable fiber as a main component to obtain a Japanese paper having excellent mechanical properties, and by using the Japanese paper in a sheet form. The inventors have found that a prepreg and a fiber-reinforced resin tubular body can be obtained, and completed the present invention.

That is, a prepreg sheet obtained by impregnating a Japanese resin containing at least one of bast fibers and vein fibers as a main component with a matrix resin, and a fiber-reinforced resin tubular body formed by winding the prepreg sheet around a core and forming a tubular shape. Is.

The bast fibers used in the present invention are classified into woody bast fibers such as 杮, 椏, goose bark, mulberry and salago, and herbaceous bast fibers such as cannabis, flax, ramie, jute and kenaf. The vein fibers include Manila hemp, sisal hemp, banana and pineapple fiber. These fibers have a high specific strength and a large aspect ratio.

The main raw material of the Japanese paper used as the reinforcing material of the prepreg of the present invention is pulped plant fiber, but when it is used as the reinforcing material of the composite material, 1) the strength of the Japanese paper, 2) the impregnation property of the resin (fiber) And the affinity with the resin) are important.

Furthermore, there are three factors of the strength of Japanese paper: 1) the strength of the fibers themselves, 2) the adhesive strength between the fibers, and 3) the friction due to the entanglement of the fibers, but among them, the bast fibers and the vein fibers are for the following reasons. Chosen from among.

The interfiber adhesion of paper fibers is due to hydrogen bonding of cellulose, which is a constituent of the fibers. Therefore, a fiber containing a large amount of cellulose having a high hydrogen bonding property is desirable. However, linters (fluff fibers) are not suitable because they often contain α-cellulose (having high crystallinity and low hydrogen bondability) and low interfiber bonding strength. ( Table 1 shows the α-cellulose content in the holocellulose of the raw material fibers for paper)

[0017]

[Table 1]

Since bast fibers and vein fibers have many fibers having a relatively round cross section and are long, a porous structure can be obtained. Therefore, the impregnation property of the matrix resin is good. On the other hand, since the wood pulp fibers used in the paper have a flat cross section and a dense structure, the impregnability of the matrix resin is poor.
(The table below shows the density of paper at the same beating degree)

[0019]

[Table 2]

Among the fibers for Washi paper, woody bast fibers such as swordfish, goose bark, mulberry and salago have a lot of soft cells, and the interfiber adhesiveness is high, and the fibers are thin and long, so that high-strength Washi paper can be obtained. .

[0021]

[Table 3]

Among the fibers for Japanese paper, hemp, flax and kenaf, which are herbaceous bast fibers, have long fibers themselves and high strength.

[0023]

[Table 4]

Among the fibers for Japanese paper, leaf fiber such as Manila hemp, sisal hemp, banana and pineapple fiber are relatively thin and long, though not as thick as bast fiber. The strength of this fiber can be adjusted by fibrillation by beating like wood pulp (NBKP, LBKP) which is a raw material for western paper.

[0025]

[Table 5]

In addition to this, a small amount of wood pulp or synthetic fiber which does not deteriorate the properties of Japanese paper can be mixed and used. (Pulping) body of bast fibers to produce fibers for paper and cooked in a chemical solution of an alkali such as a bark stripped from the foregoing timber. On the other hand, the herbaceous bast fiber is produced by separating a fiber bundle from its stem by a method such as fermentation and then steaming it with a chemical solution such as an alkali to produce a fiber for Japanese paper. In addition, leaf vein fibers are produced by removing the mesophyll from the leaves and steaming the remaining leaf veins with a chemical such as an alkali to produce fibers for Japanese paper.

The pulping conditions for San Tsubaki and Manila hemp, which are typical fibers of machine-made Japanese paper, will be described below. (Three tsubaki pulp) After air-dried white skin three tsubaki is soaked in one liquid water, it is put into a flat kettle, and 15% caustic soda and 15 times water of three tsubaki are added and heated for 1.5 hours. This is drained and washed with water,
After being dispersed in a beater, it is bleached with sodium hypochlorite, washed with water and then dedusted and dehydrated to obtain a wet pulp sheet.

(Manila hemp pulp) Manila hemp is charged into a spherical digester and caustic soda of 15% of the weight of the Manila hemp and 3 to 3 are added.
Add 4 times water and steam heat for 6 hours at a steam pressure of 5.5 kg / cm ² . This is dewatered, washed with water, dispersed with a beater, bleached with sodium hypochlorite, further washed with water to remove dust and dehydrate to obtain a wet pulp sheet.

(Adjustment) It is the papermaking process that determines the uniformity, strength characteristics and anisotropy of Japanese paper, but the handmade method, which has been handed down since ancient times, cannot provide a continuous and uniform Japanese paper. Therefore, the machine papermaking method is used, but in that case 25 mm
The above extremely long fibers are not suitable because they tend to bind due to entanglement during the process.

Therefore, the fibers are fibrillated by a disperser / beater such as a beater, cut into fibers, or a plurality of different pulps are mixed to prepare a raw material system that facilitates papermaking. (Papermaking) Machine As the papermaking machine, each papermaking machine such as a long-mesh, a short-mesh, a slanted wire, a cylinder, and a rotoformer, which are also used in the production of paper, is appropriately used. Above all, with a cylinder paper machine, the fibers are oriented in the MD direction, and it is possible to produce a highly anisotropic Japanese paper. Further, with a slanted wire or rotoformer, the fiber orientation can be arbitrarily set, and Japanese paper having an arbitrary strength ratio can be produced.

By using the above-mentioned Japanese paper as a reinforcing material, the strength of the prepreg itself is increased and the workability during molding is stabilized.
Moreover, since the Japanese paper used in the present invention has a porous structure, it tends to be a prepreg having a good resin impregnation property, and defects such as voids are less likely to occur in the molded product.

The fiber-reinforced resin molded from this prepreg has practically sufficient strength and elastic modulus. Above all, it is possible to obtain more preferable results by using a Japanese paper having anisotropy as the reinforcing material. This is because imparting anisotropy to the Japanese paper enhances the orientation of the fibers forming the Japanese paper , and as a result, the strength and elastic modulus of the Japanese paper in the fiber orientation direction increase. In particular, using Japanese paper with a tensile strength of 1400 kgf / cm2 or more and a tensile modulus of 1000 kgf / mm2 or more
It is preferable for improving the mechanical properties of the fiber reinforced resin.

The prepreg treatment of Japanese paper can be performed by a conventionally known wet method (solvent method) or dry method (hot melt method). The wet method is a method of dissolving a matrix resin, a curing agent, a catalyst and the like in an appropriate solvent to prepare a solution, impregnating this with a reinforcing material, and then heating to remove the solvent. The dry method is a method in which a resin, a curing agent, and the like are heated and melted, and a resin in a molten state is impregnated into a reinforcing material and cooled. Here, the matrix resin is a thermosetting resin such as an epoxy resin, a phenol resin, or a bismaleimide resin, or a thermoplastic resin such as polyamide, polyolefin, polyester, or polycarbonate, depending on the purpose of mechanical properties, heat resistance, workability, etc. An appropriate resin may be used among the resins.

Of these, epoxy resin is an example in which particularly preferable results are obtained. The resins include epibis type, phenol novolac type, Brized epibis type, TGDDM.
(Tetraglycidylaminodiphenylmethane), TGM
AP (triglycidylmethaaminophenol) and the like are used as hardeners such as BF3.MEA (boron trifluoride monoethylamine), DICY (dicyandiamide), DC.
MU (dichlorophenyldimethylurea), imidazole, DDS (diaminodiphenyl sulfone), DDM
(Diaminodiphenylmethane) and the like are widely used.

Particularly, in the case of 250 ° F. curing type, epibis type and novolac type epoxy resin is mainly used, DICY is often used as the curing agent, and DCMU is often used as the accelerator. Also,
In the case of 350 ° F curing type, T which is a tetrafunctional epoxy resin
Main component is GDDM, curing agent is DDS, accelerator is BF3
-Often used in MEA combinations. Where colored
In order to make the best use of the color of Japanese paper in molded products, it is necessary to consider the color of the resin. Further, the prepreg sheet can be combined with a scrim cloth or the like within a range that does not impair the object of the present invention.

To form a fiber-reinforced resin tubular body from a prepreg sheet, a sheet winding method (rolling method) using a rolling machine is generally used.

[0037]

The reason why the prepreg and the fiber-reinforced resin tubular body of the present invention have various excellent properties has not been fully clarified, but is presumed to be based on the following factors.

The Japanese paper used in the present invention has high strength, elastic modulus and toughness. This is because fibers, which are the main components of Japanese paper , have a high specific strength and a high specific elastic modulus, a large aspect ratio, and a strong adhesive strength between the fibers. In particular, anisotropic Japanese paper made by orienting fibers has high strength and elastic modulus. In addition, by using Japanese paper as the reinforcing material, the fiber content, orientation, and dispersibility are stabilized, although it is basically a short fiber reinforced resin. Further, the Japanese paper since it is porous, good impregnation of the matrix resin, hardly cause defects such as voids.

For the above reason, the fiber reinforced resin molded from the prepreg sheet of the present invention, particularly the tubular body, has a reinforcing effect close to that obtained when the continuous fiber is used as the reinforcing material, and is higher than the conventional natural fiber reinforcing material. It has a specific strength and a specific elastic modulus. On the other hand, Japanese paper and fiber reinforcement is superior to such <br/> or al impact ductile. Also, the vibration damping property is large.

Next, from the viewpoint of the molding surface, the prepreg sheet of the present invention can be made thin, which is advantageous for molding a thin tubular body or a thin tubular body. Further, as compared with a tubular body formed by sheet winding or FW of a woven fabric, there are few bent portions in the fiber, and stress concentration is less likely to occur.

[0041]

[Examples] Table 6 shows the physical properties of various papers produced by changing the raw material fibers and the composition. Here, MD is the machine direction and CD is the direction perpendicular to it. Washi Nos. 1 to 5 are the Washi used in the examples, and these have high tensile strength and tensile elastic modulus in the fiber orientation direction. Sum paper No.6 and 7 used in Comparative Example
In paper , they have low tensile strength and tensile modulus.

[0042]

[Table 6]

Table 7 shows bisphenol A type epoxy resin (Okaka Shell Epoxy Co., Ltd.) for Japanese paper shown in Table 6 .
Made, Epicoat 828) 30 parts by weight, bisphenol A
Type epoxy resin (Okaka Shell Epoxy [Co.], Epicoat 1001) 70 parts by weight, DICY as a curing agent (Okaka Shell Epoxy [Co.], Epicure DICY-7)
4 parts by weight and 4 parts by weight of DCMU as a curing accelerator were mixed to obtain an epoxy resin composition. Apply this resin on release paper, overlap this with Japanese paper ,
The prepregs of Examples 1 to 5 and Comparative Examples 1 and 2 were obtained by impregnating Japanese paper with a resin by thermocompression bonding with a press roller. The properties are shown in Table 7 .

The Japanese papers used in Comparative Examples 1 and 2 are poor in resin impregnation and have low paper strength, so that the amount of resin is large.

[0045]

[Table 7]

In order to grasp the basic mechanical characteristics of the prepreg, a prepreg was formed into a laminated plate by press molding, and a tensile test and a three-point bending test were conducted. The measurement results are shown in Table 8. The measurement is performed according to JIS K 7054 (198).
7) and JIS K 7055 (1987). It can be seen that the laminated plates formed from the prepregs of Examples 1 to 5 have high strength and elastic modulus and can be used for various products. On the other hand, the laminated plates of Comparative Examples 1 and 2 have low strength and elastic modulus and are not suitable for practical use.

[0047]

[Table 8]

Further, the results of examining the impact resistance and vibration damping property of the tubular body formed by winding the above prepreg around a core metal by sheet winding, curing the core and then molding the core body are shown in Table 9.
Shown in. Here, ◯ means good and Δ means bad.

The tubular bodies formed from Examples 1 to 5 of the present invention have good impact resistance and vibration damping properties, and can be applied in various fields such as fishing rods, sports equipment such as golf shafts, and the like. In addition, thin-walled tubes and thin tubes can be easily formed.

On the other hand, the tubular bodies molded from Comparative Examples 1 and 2 were inferior in impact resistance and vibration damping property, and could not be used for fishing rods, golf shafts and the like.

[0051]

[Table 9]

[0052]

As described in detail above, the present invention has the following excellent effects. 1) Since vegetable fiber is used as a reinforcing material, it is easier to dispose of it than conventional high performance fiber. The fiber-reinforced resin molded from this can be easily incinerated if the composition of the matrix resin is taken into consideration. 2) The tubular body of the present invention is lightweight, has practically sufficient strength and elastic modulus, and is also excellent in impact resistance and vibration damping. 3) In producing the prepreg and the tubular body, a method with high productivity can be adopted. 4) A thin tube or a thin tube can be formed. 5) By coloring the fibers or Japanese paper , a product with a quality different from the conventional surface-coated molded product can be obtained.

Claims (4)

[Claims] 1. At least one of bast fibers or vein fibers.
A prepreg sheet made by impregnating a Japanese resin containing seeds as the main component with a matrix resin. 2. The prepreg sheet according to claim 1, wherein the paper has anisotropy. 3. The tensile strength of paper in a predetermined direction is 1400 kgf / cm ^2.
The prepreg sheet according to claim 1 or 2, which has a tensile elastic modulus of 1000 kgf / mm ² or more. 4. A fiber-reinforced resin tubular body formed by winding the prepreg sheet according to claim 1, 2 or 3 around a core body and forming a tubular shape.