JP2522734B2 - Method for manufacturing plant fiber reinforced composite pipe - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for producing a plant fiber reinforced composite pipe.

[0002]

2. Description of the Related Art Pipes made of fiber-reinforced composite material obtained by impregnating synthetic fibers with chemical fibers such as carbon fibers are used in place of metal (for example, iron or aluminum) pipes instead of aircraft parts. It tends to be widely used for sports / leisure products and parts in general industrial fields.

This carbon fiber pipe is manufactured by molding a composite material obtained by impregnating carbon fiber into a synthetic resin into a pipe shape. It is also conventionally known that a paper including a Japanese paper is mainly used and a fiber-reinforced composite material obtained by impregnating the paper with a synthetic resin is formed into a pipe shape.

[0004]

As described above, the fiber-reinforced composite material obtained by impregnating the synthetic resin into the chemical fiber such as carbon fiber has no chemical reaction at the adhesive interface between the chemical fiber and the synthetic resin. , They are only joined by the physical anchor effect, and there is no clear theory regarding chemical bonding.

Further, in this fiber-reinforced composite material, since the elongation of the chemical fiber itself is very small, when the carbon fiber and the synthetic resin are applied to a pipe due to shock delamination at the adhesive interface. However, there were problems such as brittleness of impact resistance and brittle fracture of synthetic resin. Further, the composite material obtained by impregnating the paper including the above-mentioned Japanese paper with the synthetic resin has a low density, and when compounded with the synthetic resin, the fiber volume content in the composite material is small, and therefore, the tensile strength and elasticity The rate was so low that it was not suitable for pipe applications.

The present invention has been proposed in view of the above problems, and its object is to make it more resistant than a pipe made of a fiber-reinforced composite material obtained by impregnating a synthetic resin into a chemical fiber such as carbon fiber. An object of the present invention is to provide a method for producing a plant fiber-reinforced composite pipe that can improve impact strength and can improve tensile strength and elastic modulus as compared with a fiber-reinforced composite material pipe obtained by impregnating paper including Japanese paper with a synthetic resin. In point.

[0007]

In order to achieve the above object, the method for producing a plant fiber reinforced composite pipe of the present invention comprises:
A synthetic fiber is mixed with valved fiber obtained by steaming one or more kinds of plant fibers selected from wood bast fiber, hemp bast fiber, and leaf fiber with a chemical solution such as alkali, and slurry. And send it to the paper machine, dry weighing 1
After making paper in the range of 0 to 100 g / m ² and drying, it is slit into a thin tape with a desired width or twisted to form a filamentous paper, and this filamentous paper is set in a filament winding device, Impregnated with thermosetting synthetic resin in the device,
Then, the impregnated composite material is wrapped around a core material to form a pipe, and then the core material and the pipe-shaped composite material are heated to the curing temperature of the thermosetting synthetic resin to cure the thermosetting synthetic resin. It has a feature.

[0008]

(A) The fiber-reinforced composite material obtained by impregnating a synthetic resin into a chemical fiber such as carbon fiber as described above has no chemical reaction at the adhesive interface between the chemical fiber and the synthetic resin,
They are only joined by the physical anchor effect, and there is no clear theory of chemical bonding. Moreover, in this fiber-reinforced composite material, since the elongation of the chemical fiber itself is very small, delamination occurs at impact at the adhesive interface between the carbon fiber and the synthetic resin, and when applied to a pipe,
There was a problem in brittleness of impact resistance and brittle fracture of synthetic resin. (B) Further, the composite material obtained by impregnating a paper including Japanese paper with a synthetic resin as described above has a low density, and when composited with a synthetic resin, the fiber volume content in the composite material is Small, so the tensile strength and elastic modulus are low,
Although not suitable for application to pipes, the method for producing a plant fiber reinforced composite pipe of the present invention is one or more selected from wood bast fibers, hemp bast fibers, and leaf fibers as described above. Synthetic fibers are mixed with valved fibers obtained by steaming various kinds of plant fibers with a chemical solution such as alkali to form a slurry, which is then sent to a paper machine and dried and weighed 10 to 10
After making paper in the range of 0 g / m ² and drying it, slit it into a tape with a desired width or twist it into a filamentous paper, set this filamentous paper in a filament winding machine, and in the same machine. With the thermosetting synthetic resin is impregnated, then the impregnated composite material is wrapped around a core material to form a pipe, and then these core material and pipe-shaped composite material are heated to the curing temperature of the thermosetting synthetic resin, Since thermosetting synthetic resin is hardened, when compounded with synthetic resin, the fiber volume content in the pipe becomes high, high tensile strength and elastic modulus are obtained, and synthetic fiber is impregnated with chemical fiber such as carbon fiber. The impact resistance is improved compared to the fiber reinforced composite pipe obtained by the above, and the tensile strength and elastic modulus are higher than those of the fiber reinforced composite pipe obtained by impregnating paper including Japanese paper with synthetic resin. Is improved.

[0009]

EXAMPLES Next, a method for producing a plant fiber reinforced composite pipe of the present invention will be described with reference to the examples shown in FIGS. First, the filamentous paper made of plant fibers will be described. (1) Raw Material Fiber The main raw material of the filamentous paper used as the reinforcing material of the tubular composite material of the present invention is pulped plant fiber. The plant fiber is selected from wood bast fiber, hemp bast fiber and leaf fiber. In addition to this, a small amount of wood pulp or a known synthetic fiber or synthetic pulp for papermaking is mixed and used.

The wood bast fibers include fibers such as kozo, mitsumata, ganpi and mulberry. The bark peeled off from these raw trees is steamed with a chemical such as an alkali to produce pulped fibers. Hemp bast fibers include flax, ramie, hemp, jute, kenaf and the like. Fiber bundles are separated from these stems by a method such as fermentation and steamed with a chemical such as an alkali to produce pulped fibers.

Leaf fibers are produced by removing mesophyll from leaves of Manila hemp and sisal hemp and steaming the remaining fibers such as veins with a chemical solution such as alkali to produce pulped fibers. Pulp manufacturing technology from these bast fibers and leaf fibers is described in detail in "Craft Pulp / Non-Wood Pulp", March 1972: Published by The Japan Pulp and Paper Technology Association, edited by the Japan Pulp and Paper Technology Association.

Known synthetic fibers for papermaking include organic fibers such as rayon, vinylon, polyester, nylon, acrylic and aramid, and inorganic fibers such as glass fiber and carbon fiber. Of these, organic fibers have a fineness of 0.1.
It has a denier of 5 to 5 and a length of 3 to 13 mm, is well compatible with water and has a finish dispersible in water attached thereto.

The inorganic fiber has a fiber diameter of 3 to 13 μm and a length of 3
It is preferable to use one having a thickness of 13 mm. The synthetic pulp is a fine fibril formed by solidifying a polymer from a molten state or a molten state while applying a strong force, and a commercially available polyolefin valve or aramid valve is used.

Pulping Example (a) As a bast fiber, an air-dried white leather mitsumata was soaked in water overnight, then placed in a flat kettle, heated with 15% caustic soda and 15 times water for 1.5 hours. Boil. Deliquoring this,
It was washed with water, dispersed with a beater, bleached with sodium hypochlorite, washed with water, passed through a dust remover and dehydrated to obtain a wet pulp sheet.

Pulping example (b) As leaf fibers, Manila hemp was placed in a global digester with 15% caustic soda and water at a pressure of 5.5 kg / cm ^2.
Steam heating under pressure for 6 hours to pulp. This was drained, washed with water, bleached with sodium hypochlorite, washed with water, passed through a dust remover, and dehydrated to obtain a wet pulp sheet. (2) Papermaking The pulped plant fiber obtained as described above is dispersed in water and beaten to a desired beating degree using a beater or a refiner.

If necessary, different types of valved plant fibers are mixed, synthetic valves or synthetic fibers are mixed, or an additive chemical such as a wet strength improver is mixed. These are appropriately mixed in a pulper, a beater, and a rice porcher. Next, the slurry thus blended is sent to a paper machine, and the paper is dried in a dry weight range of 10 to 100 g / cm ² , dried and wound. As the paper machine, various types of paper machines such as long-mesh, short-mesh, inclined wire net, and circular net are used. Among them, in the cylinder paper machine, the fibers are oriented in the longitudinal direction, so that there is an advantage that the strength becomes high after slitting the filament paper in a slender shape. Further, the paper creped with a doctor blade during papermaking becomes bulky, and the resin impregnation property is improved. (3) Slit Put the rolled paper on a micro slitter,
Slit into a thin tape of the desired width, make a filament paper,
Take it up on a pobin. A shear-cut type slitter is most suitable as a micro slitter.

The thickness and width of the base paper slit into the filamentous paper are set within a possible range according to the quality design of the composite material. The thickness is within the above range and the width is 0.3 to 20 m.
m is preferable as the thread material. (4) (Twisting) In the filament winding process for producing a tubular composite material, (twisting) is added by filamentous paper in order to stably impregnate the filamentous paper with the resin and to perform running and winding after impregnation. Is preferred. The thread can be normally produced by using a threading machine and setting the speed low. The appropriate twist depends on the thickness and thickness of the filamentous paper, but by setting it lower than the usual yarn for clothing, good results can be obtained after resin impregnation, running and workability.

[0018]

[Table 1] Filamentous Paper Example (a) A mitsumata or Went valve sheet was dispersed in water, and a slurry was prepared by adding 1% of the absolute dry weight of the wet strength improver. A small amount of a sticky agent was used for paper making with a cylinder paper machine. The properties of the obtained mitsumata paper were as shown in Example 1 of Table 1.

This paper is slit into a width of 2 mm and 500 T
(Twist) of / m was added to prepare a thread-shaped paper for honey-comb. Filamentous paper example (b) Paper was made in the same manner using only Manila hemp wet valve sheet instead of the wet valve sheet of Example 1 in Table 1. The characteristics of the obtained Manila paper are as shown in Example 2 of Table 1. Further, in the same manner as in Example 1 in Table 1, slitting and twisting were performed to obtain a filament paper of Manila paper.

Example of filamentous paper (c) The Manila hemp wet valve seat used in Example 2 of Table 1 was mixed with PAN diameter carbon fiber having a diameter of 7 μm and a length of 6 mm in a dry weight ratio of 9: 1 and wet. A paper was made in the same manner as in Example 1 with the addition of the strength improver. The characteristics of the obtained carbon fiber-blended paper are described in Example 3 of Table 1. Further, in the same manner as in Example 1 in Table 1, slitting and twisting (twisting) were performed to obtain a mixed thread-like paper.

Since the carbon fiber has a remarkably high rigidity and the adhesiveness is not so high, the results show that the original fiber characteristics are not sufficiently reflected in the paper characteristics and the thread-like paper strength. However, the penetration of the resin was good, and the effect of fiber properties was recognized as a reinforcing material for the composite material. Set the filamentous paper created by the above method in the raw material feeding part of the filament winding device,
Appropriate tension is applied to the filamentous paper according to the purpose within the tensile strength limit of the filamentous paper.

Next, the resin is passed through the resin layer in the apparatus and impregnated with the thermosetting synthetic resin while setting a jig so that the volume content is appropriate. Next, the composite material was set in the rotating part of the filament winding device, and the metal core material 1 having a diameter of 18 mm shown in FIG. Automatically wrap under conditions such as 15 m / min. This state is shown in FIG. 2A shows a state where the composite material 2 starts to be wound, FIG. 2B shows an intermediate folded state, and FIG. 2C shows a state where the composite material 2 ends.

Next, the wound composite material 2 and the core material 1 are heated in a rotary heating furnace at a temperature of 80 ° C. for 2 hours to cure the thermosetting synthetic resin of the composite material 2, Allow to cool naturally, then decore the core material 1 and take out the molded product (plant fiber reinforced composite pipe). 3 of FIG. 3 is a molded product, and FIG. 3 shows a case where the molded product 3 is applied to a bicycle frame.

As described above, the composite material 2 is impregnated with the thermosetting synthetic resin in the filament winding apparatus and wound around the metal core material 1. The composite material 2 is thermoset by the time the winding of the composite material 2 is completed. Since the synthetic resin sufficiently penetrates into the plant fiber, the bond between the fiber and the resin becomes strong. Further, the composite material 2 is heated to the curing temperature of the thermosetting synthetic resin in a heating furnace. However, in the initial stage of heating, the thermosetting synthetic resin becomes fluid, so that the resin further penetrates into the fiber. , The hydroxyl group of plant fiber and the hydrogen group of thermosetting synthetic resin reacted positively, the chemical bond became stronger, and the bending strength of the composite pipe was improved.

FIG. 4 shows the result of measuring the bending rigidity of the composite pipe. The flexural modulus obtained from the bending test of the composite pipe is that one end of the composite pipe is fixed, two strain gauges are attached to the part about 5 mm from the fixed end for 180 degrees, and the load is applied to the part 200 mm from the fixed end. It can be obtained from the amount of strain when applied. At this time, at a lamination angle of 45 degrees, the bending elastic modulus of the composite pipe when the volume content rate is 60% (converted value) is about 11,600 MPa. A bicycle frame assembled from these pipes is shown in FIG.

[0026]

EFFECTS OF THE INVENTION (a) The fiber-reinforced composite material obtained by impregnating a synthetic resin into a chemical fiber such as carbon fiber as in the above-mentioned conventional method has no chemical reaction at the bonding interface between the chemical fiber and the synthetic resin. However, they are only joined by the physical anchor effect, and there is no clear theory regarding chemical bonding. Moreover, this fiber-reinforced composite material has a very small elongation of the chemical fiber itself, so shock delamination occurs at the adhesive interface between the carbon fiber and the synthetic resin, and when applied to pipes, impact resistance There was a problem in brittleness of properties and brittle fracture of synthetic resin. (B) Further, the composite material obtained by impregnating the paper including the Japanese paper with the synthetic resin as described above has a low density,
When compounded with a synthetic resin, the fiber volume content in the composite material is small, and therefore the tensile strength and elastic modulus are low, which is unsuitable for application to pipes, but the plant fiber reinforced composite of the present invention. As described above, the pipe manufacturing method is selected from wood bast fiber, hemp bast fiber, and leaf fiber.
Mix synthetic fibers with bulbed fibers obtained by steaming kinds or multiple kinds of plant fibers with chemicals such as alkali,
Slurry, send to paper machine, dry weighing 10
After making paper in the range of 100 g / m ² and drying, slit it into a tape with a desired width or twist it into a filamentous paper, set this filamentous paper in a filament winding machine, and in the same machine. With the thermosetting synthetic resin is impregnated, then the impregnated composite material is wrapped around a core material to form a pipe, and then these core material and pipe-shaped composite material are heated to the curing temperature of the thermosetting synthetic resin, Since thermosetting synthetic resin is hardened, when compounded with synthetic resin, the fiber volume content in the pipe becomes high, high tensile strength and elastic modulus are obtained, and synthetic fiber is impregnated with synthetic resin such as carbon fiber. The impact resistance can be improved compared to the fiber reinforced composite material pipe obtained in this way, and the tensile strength and elastic modulus can be improved compared to the fiber reinforced composite material pipe obtained by impregnating paper including Japanese paper with synthetic resin. Can be improved.

The above effect will be further supplementarily described. Thermosetting synthetic resin such as plastics penetrates into filamentous paper made from plant fiber sufficiently, and delamination becomes difficult to occur.Therefore, in a bicycle or wheelchair, the impact is softened and the human body is harmed. Function to minimize. Plant fiber (or a mixture of plant fiber and chemical fiber)
Since the filamentous paper made from is high in yarn density and strong intertwined with fibers, the strength of the filamentous paper itself is also strong, and the rupture form during the strength test such as the tensile test of the composite pipe is damaged. However, the tensile strength and elastic modulus can be improved as compared with the case of the chemical fiber alone, such as the fact that it does not break.

In addition, the filamentous paper made from vegetable fibers (or a mixture of plant fibers and chemical fibers) increases the density of the yarns by appropriately twisting the yarns, and further elongates, so that the elasticity is improved. Becomes stronger. Therefore, workability of filament winding can be improved. Further, the method for producing a plant fiber reinforced composite pipe of the present invention, a filamentous paper made of a mixture of plant fibers or a mixture of plant fibers and chemical fibers is set in a filament winding device, and heat is applied in the device. After impregnated with the cured synthetic resin, the impregnated composite material is wrapped around a core material to form a pipe, and then the core material and the pipe-shaped composite material are heated to the curing temperature of the thermosetting synthetic resin to form a pipe shape. The composite material is made to cure, and the composite material obtained by the filament winding device has continuous fibers from the beginning to the end, and commonly used sheet-like fibers (prepreg) are wrapped around the core material. The density of filamentous paper is higher than that of the method of molding, and more fibers can be added to the product. Therefore, it is lighter and the rigidity of the pipe is higher. Further, since it is not necessary to form the fiber into a sheet, the molding time can be shortened and the manufacturing cost can be reduced.

In particular, using Mitsumata as the plant fiber and thermosetting synthetic resin as the synthetic resin, the resin layers in the filament winding device are impregnated with each other to form a composite, and then the composite material is attached to the rotating part of the device. When wound around a metallic core material, heat the composite material and core material that have been wound up to the curing temperature of the thermosetting resin in a heating furnace to cure, then decore the core material and take out the molded product Can also achieve the following effects. That is, in the first stage of heating, the thermosetting synthetic resin is fluid, and the hydroxyl groups of the plant fiber and the hydrogen groups of the thermosetting synthetic resin react positively to strengthen the chemical bond. It was Therefore, the plant fiber reinforced composite pipe has effects such as improving impact resistance and enhancing flexibility. Further, even when the fiber is broken, the adhesion between the fiber and the resin is high, so that the brittleness does not show a broken form, and the risk of harming the human body can be reduced.

When a two-component room temperature curing synthetic resin is used as the thermosetting synthetic resin, the room temperature curing synthetic resin is heated to an appropriate curing temperature and molded in the same manner in order to shorten the curing time. In this case, most of the room temperature curable synthetic resin does not cause any problem even if it is heated, and when heated, the molding time tends to be shortened in proportion to the temperature. Further, when the pipe made of metal and fiber reinforced plastic is used for the core material,
Since most of the core material is used as part of the pipe, the step of removing the core material can be omitted.

[Brief description of drawings]

FIG. 1 is a perspective view showing a core material used in the method for producing a plant fiber reinforced composite pipe of the present invention.

FIG. 2 is an explanatory diagram showing a winding state of a composite material around a core material in a filament winding device.

FIG. 3 is a side view showing an example of use of a molded product (plant fiber reinforced composite pipe).

FIG. 4 is an explanatory diagram showing a measurement result of bending rigidity of a composite pipe.

[Explanation of symbols]

 1 Core material 2 Composite material 3 Molded product (plant fiber reinforced composite pipe)

Front page continuation (72) Hirotaka Ogawa 1-1501 Shiogamaguchi, Tenpaku-ku, Nagoya-shi, Aichi Prefecture, Faculty of Science and Engineering, Meijo University (72) Akio Suzumura 2-12-1 Ookayama, Meguro-ku, Tokyo No. Tokyo Institute of Technology Faculty of Engineering Department of Industrial Machinery Engineering (72) Inventor Shotaro Endo 422 Maeno City, Mino City, Gifu Prefecture Daifuku Paper Co., Ltd. In-house (72) Inventor Kenji Sakaida 3-25-23 Takanawa, Minato-ku, Tokyo Keikyu Second Building Asahi Engineering Co., Ltd. (56) Reference JP-A-57-167259 (JP, A) Japan Automotive Industry Promotion Association Technical Research Institute, Proceedings of Research Presentations (Head 3-6) 33-36

Claims (1)

(57) [Claims] 1. A valved fiber obtained by steaming one or more kinds of plant fibers selected from wood bast fiber, hemp bast fiber and leaf fiber with a chemical solution such as an alkali and synthetic fiber. After mixing and making into slurry, this is sent to a paper machine, paper is dried and weighed in the range of 10 to 100 g / m ² , dried and then slit into a tape with a desired width or twisted to form a thread. Paper, set the filamentous paper in a filament winding machine, impregnate it with thermosetting synthetic resin, and then wrap the impregnated composite material around a core to form a pipe, then these cores And a pipe-shaped composite material are heated to a curing temperature of a thermosetting synthetic resin to cure the thermosetting synthetic resin, which is a method for producing a plant fiber reinforced composite pipe.