JPWO2020218233A1 - Manufacturing method of fiber reinforced resin fasteners and fiber reinforced resin fasteners - Google Patents

Abstract

Provided is a fiber reinforced resin fastener capable of producing a fastener having excellent mass productivity and high strength. A method for manufacturing a fastener made of a fiber-reinforced resin, in which a plurality of fiber-reinforced resin sheets impregnated with a thermoplastic resin are shredded to a predetermined size in a state where the opened reinforcing fibers are oriented in a predetermined direction. The preparatory step for preparing the chop material, the charging step for charging a plurality of chop materials into the mold, and the fastening by pressurizing the chop material inside the mold while the mold is heated. It includes a pressurizing step of forming into the shape of the tool.

Description

The present invention relates to a method for manufacturing a fiber reinforced resin fastener and a fiber reinforced resin fastener.

Conventionally, metal bolts, resin bolts, and the like have been used as fasteners. Metal bolts have the disadvantage of being easily corroded and heavy, and resin bolts do not corrode, but have the disadvantage of lacking strength.

Therefore, in recent years, as a fastener that is not easily corroded, is lightweight, and has the same strength as a metal bolt or the like, a bolt made of carbon fiber reinforced resin (CFRP (Carbon Fiber Reinforced Plastic), hereinafter referred to as CFRP). Fasteners such as and nuts have been manufactured. Since the CFRP fasteners have both corrosion resistance and high strength, they can be used even under harsh usage conditions such as underwater and places susceptible to rain.

A commonly known manufacturing method for manufacturing such CFRP fasteners is CFRP in which long carbon fiber fibers contained in a carbon fiber reinforced resin are impregnated into the resin in a state of being arranged in a predetermined direction. There is a method of manufacturing a CFRP bolt by preparing a round bar made of CFRP and threading the peripheral surface of the round bar made of CFRP by cutting to cut out a thread.

Further, as in the method described in Patent Document 1, a mold in which a thermoplastic carbon fiber reinforced resin in which a reinforced carbon fiber is impregnated with a thermoplastic resin, that is, a round bar made of CFRTP (Carbon Fiber Reinforced Thermal Plastic) is heated is used. It is also known to produce CFRTP bolts by hot press molding using them.

However, in the method of manufacturing a bolt by threading a CFRP round bar by cutting, it is necessary to perform cutting for each bolt, which is inferior in mass productivity. Moreover, since the CFRP round bar usually has reinforcing fibers extending in the longitudinal direction of the round bar, the reinforcing fibers on the peripheral surface of the round bar are cut when threading is performed in order to manufacture a bolt. It is difficult to manufacture high-strength bolts.

Further, also in the method of manufacturing a bolt by hot press molding a round bar made of CFRP as described in Patent Document 1, since the reinforcing fiber is sharply deformed and cut at the thread portion, this manufacturing method can also be used. It is difficult to improve the strength of bolts.

Special Fair 7-86367 Gazette

An object of the present invention is to provide a fiber-reinforced resin fastener having excellent mass productivity and capable of producing a fastener having high strength.

In order to solve the above problems, the method for manufacturing a fiber-reinforced resin fastener of the present invention is a method for manufacturing a fiber-reinforced resin fastener, in which the opened reinforcing fibers are oriented in a predetermined direction. A preparatory step of preparing a plurality of chop materials in which a fiber-reinforced resin sheet impregnated with a thermoplastic resin is shredded to a predetermined size, and a charging step of charging the plurality of chop materials into a mold. It is characterized by including a pressurizing step of forming the shape of the fastener by pressurizing the chop material inside the mold while the mold is heated.

It is a perspective view of a bolt, a nut, and a washer as a specific example of a fastener made of a fiber reinforced resin manufactured by the manufacturing method of this invention. It is a flowchart which shows the series flow of the manufacturing method which concerns on embodiment of the manufacturing method of the fiber reinforced resin fastener of this invention. It is explanatory drawing which shows the process of manufacturing a CFRTP sheet as an intermediate material for manufacturing a CFRTP chop material which is a material of a fastener. It is explanatory drawing which shows the process of manufacturing a chop material made of CFRTP by continuously shredding a sheet made of CFRTP. It is an exploded perspective view of the mold used in the manufacturing method of this invention. It is explanatory drawing which shows the charging process which puts a plurality of chopped materials or chopped sheets into a mold in the manufacturing method of this invention. It is explanatory drawing which shows the process of pushing a chop material into the inside of a mold in a charging process. It is explanatory drawing which shows the pressurizing process which presses the chop material in the manufacturing method of this invention inside a mold, and forms a bolt which is a fastener. It is explanatory drawing which shows the process of disassembling a mold after a pressurizing process. It is explanatory drawing which shows the process of taking out a molded bolt from a mold. It is explanatory drawing which shows the chopped sheet manufacturing process which manufactures a chopped sheet by impregnating a thermoplastic film with a chopped material which is a modification of the manufacturing method of this invention. It is sectional drawing of the bolt of the comparative example 1. FIG. In (a), a rectangular chop material (thickness 50 μm) having a size of 5 mm × 20 mm and a PA6 film as a matrix (base material) were used, and the carbon fiber was manufactured under production conditions in which the fiber volume content was 53%. A cross-sectional view of the bolt, (b) is a cross-sectional view of the bolt of Comparative Example 3. It is sectional drawing which shows the other example of the mold which can be used by the manufacturing method of this invention. It is sectional drawing which shows the other example of the mold which can be used by the manufacturing method of this invention. It is sectional drawing which shows the other example of the mold which can be used by the manufacturing method of this invention. It is sectional drawing which shows the other example of the mold which can be used by the manufacturing method of this invention. It is explanatory drawing about the evaluation of the filling degree of a fiber when observing the cross section of the fiber reinforced resin bolt.

Hereinafter, a preferred embodiment of the present invention will be described in detail with reference to the accompanying drawings.

FIG. 1 shows bolts B, nuts N, and washers W as specific examples of fiber-reinforced resin fasteners manufactured by the manufacturing method of the present invention. Fasteners such as these bolts B are manufactured by hot press molding a chop material obtained by shredding a fiber reinforced resin sheet impregnated with a reinforced fiber into a thermoplastic resin.

That is, the method for manufacturing the fastener made of the fiber reinforced resin of the present embodiment is
(A) A preparatory step of preparing a plurality of chop materials in which a fiber-reinforced resin sheet impregnated with a thermoplastic resin is shredded to a predetermined size with the opened reinforcing fibers oriented in a predetermined direction.
(B) The loading process of loading multiple chop materials into the mold and
(C) It is characterized by including a pressurizing step of forming a fastener into a shape by pressurizing a chop material inside the die while the die is heated.

As the reinforcing fiber, a fiber bundle obtained by opening a reinforcing fiber bundle such as a carbon fiber bundle, a glass fiber bundle, an aramid fiber bundle, or a ceramic fiber bundle (that is, a fiber bundle spread in a strip shape) is used. In particular, carbon fiber bundles are preferable in terms of strength and corrosion resistance. Further, among the carbon fibers, PAN (polyacrylonitrile) -based carbon fibers are particularly preferable because they have higher strength than other materials.

Examples of the thermoplastic resin include polypropylene, polyethylene, polystyrene, polyamide (nylon 6, nylon 66, nylon MXD6, nylon 9T, nylon 11, nylon 12, etc.), polyacetal, polycarbonate, acrylonitrile-butadiene-styrene copolymer (ABS), and the like. Polyethylene terephthalate, polybutylene terephthalate, polyetherimide, polyethersulfone, polyphenylene sulfide, polyetherketone, polyetheretherketone, polyetherketoneketone, fluororesin and the like are used. Further, a resin obtained by mixing two or more kinds of these thermoplastic resins into a polymer alloy may be used.

The thermoplastic resin is used in the form of a sheet when the fiber-reinforced resin sheet is produced, but is used in the form of a woven sheet material or a knitted sheet material composed of fibers made of a thermoplastic resin material, and further in the form of a non-woven fabric. You may.

Specifically, the method for manufacturing the fastener made of fiber reinforced resin of the present embodiment is executed by the procedure shown in the flowchart of FIG. Here, the bolt B will be described as an example of the fastener to be manufactured.

First, a sheet made of thermoplastic carbon fiber reinforced resin (CFRTP) (hereinafter referred to as CFRTP sheet) is manufactured as a fiber reinforced resin sheet (S1 in FIG. 2).

CFRTP sheets are continuously manufactured, for example, using a sheet manufacturing apparatus for manufacturing CFRTP sheets as shown in FIG.

The sheet manufacturing apparatus shown in FIG. 3 is an apparatus for continuously producing a CFRTP sheet S by using a carbon fiber bundle F1 as a reinforcing fiber and a thermoplastic resin sheet R1.

Specifically, the sheet manufacturing apparatus is located below a group of a plurality of pairs (two pairs in FIG. 3) of heating rolls 1 arranged side by side in the vertical direction and the above-mentioned group of heating rolls 1, and is vertically above and below each other. A pair of endless belts hung around a plurality of pairs of cooling rolls 2 arranged side by side in the direction (two pairs in FIG. 3) and columns of two heating rolls 1 and two cooling rolls 2 arranged in the vertical direction, respectively. 3 is provided with a pair of drawer rolls 4 located below the pair of endless belts 3, and a bobbin 5 for winding.

Further, although not shown, a fiber-opening mechanism is provided in the vicinity of the heating roll 1 at the uppermost stage to continuously form the fiber-spreading fiber F2 by opening the carbon fiber bundle F1 and spreading it in a band shape. There is. The fiber opening mechanism may be, for example, a mechanism capable of expanding the fiber bundle and flattening the long fibers so as to extend in the same direction. Various mechanisms such as a mechanism for applying and spreading are used.

In the manufacturing apparatus shown in FIG. 3, the CFRTP sheet S is manufactured by sandwiching the thermoplastic resin sheet R1 between the open fiber F2 from both the front and back sides.

The two pairs of heating rolls 1 are heated by an electric heater, a heating fluid, or the like, respectively. The two pairs of heating rolls 1 heat the spread fiber F2 while sandwiching the spread fiber F2 and the thermoplastic resin sheet R1 from both sides in a state of being overlapped with each other via the endless belt 3, thereby heating the spread fiber F2 to the thermoplastic resin sheet. R1 is continuously impregnated.

Each of the plurality of pairs of cooling rolls 2 is cooled by a cooling fluid or the like. The plurality of pairs of cooling rolls 2 are CFRTP sheets having a predetermined thickness by cooling the thermoplastic resin sheet R1 in a state of being impregnated with the spread fiber F2 via the endless belt 3 while sandwiching it from both sides and sending it downward. S is continuously molded.

The pair of drawer rolls 4 continuously pull downward while applying tension to the manufactured CFRTP sheet S.

The bobbin 5 for winding is rotated by a drive source such as a motor, and the CFRTP sheets S drawn out by the pair of drawer rolls 4 are sequentially wound to form a roll-shaped CFRTP sheet S.

The CFRTP sheet can also be manufactured by a method in which the thermoplastic resin sheet and the opened reinforcing fibers are flowed together in a predetermined direction and wound up without using the endless belt 3 shown in FIG.

Then, as shown in FIG. 4, the produced CFRTP sheet S is shredded to produce a chop material C (S2 in FIG. 2).

Specifically, as shown in FIG. 4, while pulling out the CFRTP sheet S wound in a roll shape, a cutter having a large number of blades arranged at equal intervals in the width direction of the sheet S in the section I or the like is used. Using, the sheet S is continuously cut in the longitudinal direction so as to form a large number of strips having a predetermined width. Then, in the section II, the sheet S is cut into strips by a predetermined length by using a rotary cutter or the like having a blade extending in the width direction of the sheet S. Thereby, the chop material C having a predetermined size can be continuously produced.

The size of the chop material C is selected in consideration of various conditions such as the size of the bolt B to be molded, the size of the charging port 12 of the mold 11 described later, and the shapeability at the time of molding.

Then, as the charging step of the above (B), a large number of chop materials C are charged into the mold 11 through the charging port 12 in a state where the mold 11 shown in FIGS. 5 to 6 is heated.

The mold 11 may be configured as long as it can be pressure-molded while heating the chop material C inside, and is composed of, for example, split dies 11a and 11b divided into two in the vertical direction. A slot 12 is formed at the upper end of the mold 11. Inside the mold 11, a space portion (cavity) 13 corresponding to the shape of the bolt B (fastener) to be molded is formed. The space portion 13 communicates with the input port 12. The space portion 13 includes a shaft portion side space portion 13a corresponding to the shape of the shaft portion on which the screw of the bolt B is formed, and a head side space portion 13b corresponding to the shape of the hexagonal head of the bolt B. Have. Therefore, a female screw is formed on the inner surface of the shaft portion side space portion 13a, and a hexagonal columnar hollow recess is formed on the head side space portion 13b.

The two split molds 11a and 11b are connected in a state where the mating surfaces 14 are brought into contact with each other to form a space portion 13 corresponding to the shape of the bolt B. Specifically, the two split dies 11a and 11b are connected by inserting a bolt into a through hole 15 formed in the horizontal direction in the two split dies 11a and 11b and fastening a nut to the bolt.

The mold 11 shown in FIGS. 5 to 6 has two vertical split dies 11a and 11b, and one through hole 12 is formed on the bolt head side of the space portion 13. However, the manufacturing method of the present invention does not limit the structure of the mold, and it is possible to adopt molds having various shapes.

For example, as a modification of the present invention, as in the mold 21 shown in FIG. 14, a through hole 21c is formed in the bolt-shaped space portion 21a and communicates with the shaft portion side space portion 21b, and the through hole 21c is formed to penetrate the shaft portion side. The structure may be such that the pressure P can be applied from the hole 21c into the space portion 21a.

Further, as another modification, as in the mold 22 shown in FIG. 15, two through holes, that is, a through hole 22c communicating with the shaft side space portion 22b of the bolt-shaped space portion 22a, and a head. The structure may be such that a through hole 22e communicating with the partial side space portion 22d is formed. In the structure of FIG. 15, the pressure P can be applied to the space portion 22a from the two through holes 22c and 22e.

As yet another modification, the horizontal split mold 23 shown in FIG. 16 may be used. The mold 23 has an upper mold 23a and a lower mold 23b as two split molds that can be fitted by a mating surface 23d extending in the horizontal direction. By combining the upper mold 23a and the lower mold 23b, a bolt-shaped space portion 23c is formed.

As yet another modification of the horizontal split mold, two through holes 24e and 24f may be formed as in the horizontal split mold mold 24 shown in FIG. In the structure of FIG. 17, a bolt-shaped space portion 24c is formed by aligning the upper die 24a and the lower die 24b on the horizontal mating surface 24d. Of the space portions 24c, the shaft portion side space portion 24c1 communicates with the through hole 24e, and the head side space portion 24c2 communicates with the through hole 24f. It is possible to apply the pressure P into the space portion 24c from the two through holes 24e and 24f.

The heating method of the mold 11 may be any method as long as it can be heated to a temperature at which the chop material C melts (for example, 250 to 300 ° C. around 270 ° C.), and is not particularly limited in the present invention. For example, in addition to heating with infrared rays or a burner, heating may be performed by induction heating or the like.

The present invention is not particularly limited as to the method of charging the chop material C into the mold 11, and a predetermined amount of the chop material C may be charged by a mechanical method using a charging device or manually.

When the chop material C is charged, the directions of the chop material C are randomly arranged so that the carbon fibers inside the chop material C are oriented in different directions so that the carbon fibers in the chop material C do not extend in the same direction (that is, the chop material C is oriented in different directions). It is possible to ensure the random orientation of the bolt B after molding by charging the bolt B (so that it becomes). Therefore, the size of the chop material C should be such that a large number of chop materials C face each other in different directions at the time of charging in consideration of the opening area of the charging port 12 and the volume and shape of the space portion 13. It is preferable that it is set to be.

Then, as shown in FIG. 7, the chop material C is pushed into the mold 11 (S4 in FIG. 2). Specifically, the pressing rod 16 is inserted into the charging port 12 of the mold 11, and the chop material C charged into the mold 11 is pushed into the space (cavity) 13 inside the mold 11 by the pressing rod 16. .. As a result, the chop material C is uniformly dispersed and packed inside the space portion 13. When the chop material C is pushed in by the pressing rod 16, the chop material C may be pushed in through a lid having a size substantially the same as that of the charging port 12, or may be pushed directly in the lower end surface of the pressing rod 16. If the chop material C does not leak when it is pushed in, it may be pushed in by an appropriate method. The step (S4) of pushing the chop material C into the mold 11 is not essential in the manufacturing method of the present invention and may be omitted.

Then, as shown in FIG. 8, the chop material C inside the die 11 is pressed by using the hot press machine 17 (S5 in FIG. 2). The heat press machine 17 has a pedestal 17a and a pressurizing portion 17b arranged above the pedestal 17a. The pedestal 17a has a heater and heats the mold 11 placed on the pedestal 17a. With the mold 11 mounted on the pedestal 17a, the pressurizing portion 17b descends, so that the pressurizing portion 17b pressurizes the chop material C inside the heated mold 11 via the pressing rod 16. As a result, a large number of groups of chop materials C are melted and deformed inside the space 13 under high temperature and high pressure inside the mold 11 to be formed into the shape of the bolt B.

After forming the bolt B, as shown in FIG. 9, the mold 11 is disassembled and divided into two split molds 11a and 11b (S6 in FIG. 2).

Finally, as shown in FIG. 10, the bolt B is removed from the space 13 of one of the split molds 11a of the mold 11 and demolded (S7 in FIG. 2), and a series of methods for manufacturing the bolt B is performed. The process ends.

The fiber-reinforced resin fastener such as the bolt B according to the embodiment of the present invention is impregnated with the thermoplastic resin and the thermoplastic resin in a state where the orientation is not specified by manufacturing by the above-mentioned manufacturing method. A fiber-reinforced resin fastener formed of fibers, wherein the fiber length of the reinforcing fibers is in the range of 5 to 100 mm, preferably 5 to 40 mm, and more preferably 5 to 20 mm. It is possible to have the characteristic that the volume content of the reinforcing fiber in the thermoplastic resin is in the range of 30 to 80%, preferably 30 to 60%.

In the above fastener, the state in which the orientation of the reinforcing fibers is not specified, that is, the reinforcing fibers in a state having a random orientation can be impregnated with a thermoplastic resin, moreover, the conditions in the reinforcing fibers, fiber length of 5~100mm Since it is within the range and the volume content of the thermoplastic resin is within the range of 30 to 80%, it is excellent in mass productivity and has high strength.

Under the above conditions, as shown in Examples described later, when the fiber length of the reinforcing fiber is 5 to 100 mm, preferably 5 to 40 mm, and more preferably about 5 to 20 mm, the tensile strength is excellent. If the bolt can be manufactured and the volume content of the reinforcing fiber is in the range of 30 to 80%, preferably 30 to 60%, it is possible to secure high strength and formability of the bolt. It is based on a certain point.

(Characteristics of this embodiment)
In the above-mentioned method for manufacturing a fastener made of fiber-reinforced resin according to the present embodiment, the opened reinforcing fiber F2 is oriented in a predetermined direction as a material for a fastener such as a bolt B, as shown in FIGS. 3 to 4. A plurality of chop materials C formed by shredding a fiber-reinforced resin sheet such as CFRTP sheet S impregnated with the thermoplastic resin R1 into a predetermined size are prepared. Then, a plurality of chop materials C are put into the inside of the mold 11 and pressure-molded in a state where the chop materials are heated. Since the chop material C has good shapeability, that is, followability to the cavity shape of the mold, it is excellent in mass productivity as compared with the case where a rod-shaped member made of a conventional fiber reinforced resin is cut and manufactured.

That is, the fiber-reinforced resin fasteners manufactured by the manufacturing method of the present embodiment can be mass-produced by performing hot press molding as in the pressurization step of (C) above. Further, if the used fastener is reheated to melt the thermoplastic resin, it can be reused for other purposes.

Moreover, since the group of a plurality of chop materials used as the material of the fastener has random orientation, there is a low possibility that the reinforcing fibers contained in the chop material will be cut even if pressure molding is performed. Further, since the fastener after molding also maintains a constant fiber length, the strength of the fastener (for example, torsional strength, shear strength, etc.) can be improved. This makes it possible to manufacture a fiber-reinforced resin fastener having excellent mass productivity and high strength.

Next, as an example of the present invention, the strength and shapeability of the CFRTP bolt B manufactured by the method for manufacturing the fiber-reinforced resin fastener of the present embodiment will be evaluated. As the bolt B, a hexagonal full-threaded bolt having a size of M8 × 30 (that is, a hexagonal full-threaded bolt having an outer diameter of 8 mm and a shaft portion having a length of 30 mm) will be described as an example.

The CFRTP chop material used as the material for the bolt B is formed by shredding the CFRTP sheet. The CFRTP sheet consists of a sheet in which a large number of long fibers made of carbon fibers extend in a single direction, that is, a UD sheet, specifically, an opened PAN (polyacrylonitrile) -based carbon fiber in a single direction. It is manufactured by impregnating nylon 6 (PA6), PA9T, PPS, etc., which is a matrix (base material) while stretching.

The size of the chop material formed by shredding the above CFRTP sheet is shaped with respect to the cavity in consideration of the size of the mold inlet and the cavity for forming the M8 bolt. It is set to have a good size.

The volume content (Vf) of carbon fibers in the CFRTP sheet and the chopped material obtained by chopping it is 35 to 53%.

When a chop material (or a chopped sheet in which the chop material is fixed to a carrier sheet (for example, a film made of a thermoplastic resin)) is put into a mold and the bolt B is press-molded, for example, heating at a molding temperature of 270 ° C. is performed. Under the condition, the chopped material (or chopped sheet) is pressed with a pressing pressure of 37 MPa. Then, with the heating stopped, as a cold press, the bolt B is further pressed at a press pressure of 73 MPa at room temperature (for example, about 25 ° C.) to form a bolt B having a predetermined shape.

The tensile breaking load, formability, and fiber filling degree of the CFRTP bolt B manufactured by the manufacturing method of the present embodiment are evaluated as follows.

The tensile breaking load test is carried out by a test method conforming to JIS B 1051.

As shown in Table 1, as a bolt B made of CFRTP manufactured by the method for manufacturing a fastener made of fiber reinforced resin of the present embodiment, a hexagonal full screw having a size of M8 × 30 under the conditions of Examples 1 to 7. Manufacture bolts. At the same time, an M8 nut corresponding to the bolt is manufactured under the conditions of the eighth embodiment.

In Example 1, a rectangular chop material (thickness 50 μm) having a size of 5 mm × 10 mm (that is, width 5 mm and length 10 mm) and a PA6 film as a matrix (base material) are used. The fiber volume content (Vf) of the carbon fiber is 53%.

In Example 2, a rectangular chop material (thickness 50 μm) having a size of 5 mm × 20 mm and a PA6 film as a matrix (base material) are used, and the fiber volume content of carbon fibers is 35%.

In Example 3, a rectangular chop material (thickness 50 μm) having a size of 5 mm × 100 mm and a PA6 film as a matrix (base material) are used, and the fiber volume content of carbon fibers is 53%.

In Example 4, a 40 mm square (that is, 40 mm in both vertical and horizontal directions) square chop material and a PA6 film as a matrix (base material) are used, and the fiber volume content of carbon fibers is 53%.

In Example 5, a rectangular chop material (thickness 50 μm) of 5 mm × 20 mm and a PA9T film having better physical properties than PA6 are used as the matrix (base material), and the fiber volume content of the carbon fibers is high. It is 53%.

In Example 6, a rectangular chop material having a size of 5 mm × 10 mm and a PPS film as a matrix (base material) are used. The fiber volume content of the carbon fiber is 47.7%.

In Example 7, a chopped sheet (that is, a sheet in which a chopped material is fixed to a carrier sheet (a film made of a thermoplastic resin)) and a PA6 film as a matrix (base material) are used, and the fiber volume content of carbon fibers is high. It is 53%.

Example 8 is an M8 nut corresponding to a bolt manufactured under the conditions of Examples 1 to 7, and is used as a 5 mm × 20 mm rectangular chop material (thickness 50 μm) and a matrix (base material). A PA6 film is used, and the fiber volume content of the carbon fiber is 53%.

On the other hand, in Table 2, in order to compare with Examples 1 to 8, hexagonal full screw bolts having a size of M8 × 30 are manufactured under the conditions of Comparative Examples 1 to 7. At the same time, an M8 nut corresponding to the bolt is manufactured under the conditions of the eighth embodiment.

In Comparative Example 1, it is a UD sheet (thickness 180 μm), and a PA6 film is used as a matrix (base material).

In Comparative Example 2, a tape material (thickness 50 μm) having a size of 5 mm × 1000 mm is rolled and put into a mold. A PA6 film is used as the matrix (base material), and the fiber volume content of the carbon fibers is 53%.

Further, in Comparative Example 3, a rectangular chop material (thickness 50 μm) of 5 mm × 20 mm and a PA6 film as a matrix (base material) are used, and the fiber volume content of the carbon fibers is 53% under the production conditions. After manufacturing the bolt, the thread is machined out.

In Comparative Example 4, it is an injection product of a material of a short fiber reinforced product containing glass fiber, and PPS is used as a matrix (base material). The content of glass fiber (GF) is 40% (% by weight).

In Comparative Example 5, it is an injection product of a material of a short fiber reinforced product containing glass fiber, and MXD6 is used as a matrix (base material). The content of glass fiber (GF) is 50% (% by weight).

In Comparative Example 6, it is an injection product of a resin material, and PC (polycarbonate) is used as a matrix (base material).

In Comparative Example 7, it is an injection product of a resin material, and PEEK (polyetheretherketone) is used as a matrix (base material).

In Comparative Example 8, it is an M8 nut corresponding to a bolt manufactured under the condition of Comparative Example 4, is an injection product of a material of a short fiber reinforced product, and PPS is used as a matrix (base material). The content of glass fiber (GF) is 40% (% by weight).

As a result of conducting a specified number of tensile tests on the bolts and nuts manufactured by Examples 1 to 8 and Comparative Examples 1 to 8, the tensile tensile breaking load for each example was obtained, and the formability and fiber filling were obtained. The degree was evaluated. The results are shown in Tables 1-2.

As shown in Tables 1 and 2 above, the tensile breaking load of the CFRTP bolt manufactured by the manufacturing method of the present embodiment (that is, the manufacturing method of pressure molding using a CFRTP chop material) is determined. As shown in Examples 1-7, it is in the range of 4921-7890N. Moreover, in Examples 1 to 7, the evaluation of the moldability is Δ (molding is completed at a rate of about 70%) and 〇 (all molding is completed). Further, in Examples 1 to 7, the evaluation of the filling degree of the fiber is also 〇 (filling is completed to the entire screw thread at a rate of about 70%) and ◎ (filling is completed to the tip of all threads) (of the fiber in FIG. 18). See the explanatory diagram for the evaluation of the filling degree). Note that FIG. 18 shows a cross-sectional view of the thread 31 of the bolt, where 31a is the tip of the thread, 32 is the carbon fiber, and 33 is the matrix resin.

On the other hand, in Comparative Example 1, the tensile breaking load of the bolt manufactured by pressure-molding the UD sheet as it is is only 2537N, which is far below the minimum value of 4921N in the above range in Examples 1 to 7. Further, the evaluation of the filling degree of the fiber is also × (the tip of the screw thread could not be filled) (see FIG. 18).

In Comparative Example 1 above, although the bolt can be molded using the UD sheet, the tensile breaking load is only 2537N, and the tensile breaking of Examples 1 to 4 and 7 using the matrix of the same material (PA6 film) is used. Significantly lower than the load (4921-7890N). This is due to the decrease in rigidity of the bolt B molded according to Comparative Example 1 due to the void V (vacancy) generated at the inner part of the thread G in the cross section of the bolt B shown in FIG. It is believed that there is. It is believed that the void V was generated during bolting due to the continuous fibers in the UD sheet (ie, a layer of reinforcing fibers of long fibers oriented in a predetermined direction) blocking the air escape path. The void V shown in FIG. 12 was confirmed by observing the cut surface of the bolt B with a laser microscope. On the other hand, in the bolts B of Examples 1 to 4 and 7, no void V was found even when the cross section was observed.

When the tape material was rolled and pressure-molded as in Comparative Example 2, the bolt could not be formed, the tensile breaking load could not be measured, and the formability and the filling degree of the fiber could not be evaluated.

Comparative Example 3 is manufactured under the manufacturing conditions in which a rectangular chop material (thickness 50 μm) of 5 mm × 20 mm and a PA6 film as a matrix (base material) are used, and the fiber volume content of carbon fibers is 53%. The M8 bolt (8 mm in diameter) is further machined to cut threads. As a result, the tensile breaking load (2084N) of Comparative Example 3 is significantly lower than the tensile breaking load (4921 to 7890N) of Examples 1 to 4 and 7. The cause of this is a comparative example after the shaving process shown in FIG. 13 (b) as compared with the state in which the reinforcing fibers F are continuously extended inside the bolt B1 before the shaving process shown in FIG. 13 (a). It is considered that the cause is that the reinforcing fiber F is cut inside the bolt B2 of No. 3 and the tensile strength is lowered.

Looking at the respective tensile breaking loads (3215N and 4386N) when the injection product of PPS containing glass fiber as in Comparative Example 4 and the injection product of MXD6 containing glass fiber as in Comparative Example 5 are also used. It can be seen that it is sufficiently lower than the tensile breaking load (4921 to 7890N) of Examples 1 to 4 and 7.

Further, as an example of the injection product of the resin containing no fiber, the tensile breaking load (2121N and 3258N) when the injection product of PC as in Comparative Example 6 and the injection product of PEEK as in Comparative Example 7 are used. ), It can be seen that it is sufficiently lower than the tensile breaking load (4921 to 7890N) of Examples 1 to 4 and 7.

Further, as shown in Example 8, the tensile breaking load of the nut made of CFRTP manufactured by the manufacturing method of the present embodiment (that is, the manufacturing method of pressure molding using a chop material made of CFRTP) is 9292N. It is a very high value. Moreover, in Example 8, the evaluation of moldability is 〇 (all molding is completed), and the evaluation of the fiber filling degree is also ⊚ (all filling is completed up to the thread tip).

On the other hand, the tensile breaking load of the nut manufactured in Comparative Example 8, that is, the nut which is an injection product of PPS containing glass fiber, is only 3290N, which is much lower than the tensile breaking load (9292N) of the nut of the above embodiment. ing.

Further, as shown in Table 3 below, the weight of the carbon fiber (CF) M8 bolts manufactured in Examples 1 to 7 is 3 g, and the weight of the stainless steel (SUS) M8 bolts. It is smaller than 1/5 and very light compared to (16 g). Further, the weight of the carbon fiber (CF) M8 nut manufactured in Example 8 is 1.2 g, which is 1 as compared with the weight of the stainless steel (SUS) M8 nut (5.4 g). It is about /4 to 1/5 small and very light.

Looking at the test results in Table 1 above, if the fiber length of the reinforcing fiber contained in the chop material is 5 to 100 mm, preferably 5 to 40 mm, and more preferably 5 to 20 mm, the tensile strength is excellent. It is believed that bolts and nuts can be manufactured. Further, it is presumed that the bolts and nuts manufactured according to Examples 1 to 8 have a high torsional strength in consideration of the excellent tensile strength.

Here, it is considered that the longer the fiber length of the chop material contributes to the improvement of the strength of the bolt, but when considering the formability, the fluidity (MFR) of the resin material of the matrix is 2 to 50 g. / 10 min, preferably 5 to 30 g / min. With this value, it is possible to maintain good formability.

Further, it is preferable that the volume content of the reinforcing fibers contained in the matrix in the chop material is in the range of 30 to 80%. If it is less than 30%, the strength of the bolt will be low, and if it exceeds 80%, the shapeability will decrease and molding will be difficult. Therefore, from the viewpoint of ensuring the high strength and shapeability of the bolt, the volume of the reinforcing fiber is contained. The rate is preferably within the above range, more preferably 30 to 60%.

(Modification example)
(A)
In the above embodiment, as shown in FIG. 6, a large number of chop materials C obtained by shredding the CFRTP sheet are put into the mold 11, hot press molding is performed in the state of the chop material C, and bolts B and the like are fastened. Although the tool is manufactured, the present invention is not limited to this, and even if a large number of chop materials C are arranged in a plane and united into a sheet-like member, that is, a chopped sheet CS is put into a mold. good.

That is, as a modification of the manufacturing method of the present invention, in this manufacturing method, after the above-mentioned (A) preparation step of the chopping material, (D) a plurality of chopping materials are arranged in a plane and united to produce a chopped sheet. It further includes a chopped sheet manufacturing step (S21 in FIG. 2), and is characterized in that the chopped sheet is packed inside the mold in the above-mentioned (B) charging step.

The chopped sheet manufacturing step is only required to be able to manufacture a chopped sheet CS in which a plurality of chopped materials C are arranged in a plane and united, and the present invention is not particularly limited to the use of a film for combining the plurality of chopped materials C. ..

As an example of the chopped sheet manufacturing process, for example, a chopped sheet is manufactured by impregnating a plurality of chopped materials in a state of being dispersed on at least one surface of a thermoplastic resin film. Specifically, as shown in FIG. 11, the thermoplastic resin film R2 is continuously sent out, and a large number of chop materials C are dispersed on both sides of the thermoplastic resin film R2 as in the section XI. By pressurizing while heating with a heating roll or the like, a chopped sheet CS in which the chop material C is dispersed on both sides is manufactured. The chop material C may be impregnated only on one of both sides of the thermoplastic resin film R2.

If the thermoplastic resin film R2 is the same material (for example, nylon 6 (PA6)) as the thermoplastic resin sheet R1 (see FIG. 3) used in manufacturing the above-mentioned chop material C, the matrix of the chop material C is used. Since it is the same material as the (base material), the chop material C is easily impregnated into the thermoplastic resin film R2.

The thicknesses of the thermoplastic resin sheet R1 and the thermoplastic resin film R2 are appropriately selected in consideration of the manufacturing conditions for producing the chopped material C and the chopped sheet CS.

The manufactured chopped sheet CS is deformed so as to be easily inserted into the charging port 12 of the mold 11, and is packed into the mold 11 in a rolled state, for example (see FIG. 6). When the chopped sheet CS is large, it may be cut out to a size corresponding to the volume of the bolt B to be molded and then rolled up.

In such a manufacturing method, a plurality of chopped materials C are formed into a chopped sheet CS in which a plurality of chopped materials C are arranged in a plane and united, and the chopped sheet CS is packed inside the mold 11 to form a plurality of chopped materials C. It is possible to easily disperse and charge the mold 11 into the space 13 (cavity) 13. As a result, it is not necessary to perform another work to uniformly disperse the chopped material C after charging in the space 13 of the mold 11, and the mass productivity is further improved.

Moreover, since a constant fiber length is maintained even in the chop material C inside the chopped sheet CS, it is possible to manufacture fasteners such as bolts B having long fibers, and to improve the strength of the fasteners. Is possible.

Further, in the above modification, the chopped sheet CS can be easily produced by impregnating the plurality of chopped materials C in a state of being dispersed on at least one surface of the thermoplastic resin film R2. Further, the possibility that the chop material C is separated from the chopped sheet CS after production is reduced.

(B)
Further, as another modification, the chopped sheet CS produced in FIG. 11 above may be shredded into a size that can be easily put into the mold 11.

That is, in the manufacturing method as another modification of the present invention, after the above-mentioned (D) chopped sheet manufacturing step, as shown in the sections XII to XIII of FIG. 11, the chopped sheet CS is more than the chopped material C. A chopped sheet shredding step of shredding into a large predetermined size is further included, and in the above-mentioned (B) loading step, the chopped sheet T (see FIGS. 6 and 11) is packed inside the mold 11. It is characterized by that.

In the above manufacturing method, the chopped sheet T shredded to a predetermined size larger than the chop material C is packed inside the mold 11, so that the chopped sheet is rolled or deformed before being packed inside the mold 11. No separate work is required, and it is easy to put it in the mold. At the same time, it is possible to disperse the chop material C more uniformly in the space 13 of the mold 11 than to put it into the mold 11 as it is. As a result, mass productivity is further improved.

(C)
In the manufacturing method of the above embodiment, an example is shown in which a chopped sheet is produced by arranging a plurality of chopped materials in a plane and united, and the chopped sheet is packed inside a mold. It is not limited to the above, and it is not limited to the shape of multiple chop materials to be packed into the mold. Therefore, as a modification of the present invention, a rod-shaped plurality of chop materials may be put into a mold and pressed.

<Summary of embodiments>
The embodiments are summarized below.

The method for manufacturing a fiber-reinforced resin fastener according to the above embodiment is a method for manufacturing a fiber-reinforced resin fastener, in which the opened reinforcing fibers are impregnated with the thermoplastic resin in a state of being oriented in a predetermined direction. A preparatory step of preparing a plurality of chop materials in which the fiber-reinforced resin sheet is shredded to a predetermined size, a charging step of charging the plurality of chop materials into the inside of the mold, and a state in which the mold is heated. It is characterized by including a pressurizing step of forming the shape of the fastener by pressurizing the chop material inside the mold.

In such a manufacturing method, the fiber-reinforced resin sheet impregnated with the thermoplastic resin is shredded into a predetermined size as a material for the fastener in a state where the opened reinforcing fibers are oriented in a predetermined direction. Prepare multiple chops. Then, a plurality of chop materials are put into the inside of the mold, and the chop materials are pressure-molded in a heated state. Since the chop material has good shapeability, that is, it can follow the cavity shape of the mold, it is excellent in mass productivity as compared with the case where a rod-shaped member made of a conventional fiber reinforced resin is cut and manufactured.

Moreover, since the group of a plurality of chop materials used as the material of the fastener has random orientation (that is, the property that the orientation of the reinforcing fibers is not specified), even if pressure molding is performed, the reinforcing fibers contained in the chop material are present. Low risk of disconnection. Further, since the fastener after molding also maintains a constant fiber length of the reinforcing fiber, the strength of the fastener can be improved. This makes it possible to manufacture a fiber-reinforced resin fastener having excellent mass productivity and high strength.

The above-mentioned method for manufacturing a fiber-reinforced resin fastener, further including a chopped sheet manufacturing step of manufacturing a chopped sheet in which a plurality of chopped materials are arranged in a plane and united after the preparatory step, and the feeding step. It is preferable to pack the chopped sheet inside the mold.

In such a manufacturing method, the plurality of chopped materials are arranged in a plane and combined into a chopped sheet, and the chopped sheets are packed inside the mold, whereby the plurality of chopped materials can be easily placed in the space of the mold. It will be possible to disperse and input. As a result, it is not necessary to perform another work to uniformly disperse the chopped material after charging in the space of the mold, and the mass productivity is further improved.

Moreover, since a constant fiber length is maintained even in the chopped material inside the chopped sheet, it is possible to manufacture a fastener having long fibers, and it is possible to improve the strength of the fastener.

In the method for manufacturing a fiber-reinforced resin fastener, the chopped sheet manufacturing step is performed by impregnating the plurality of chopped materials in a state of being dispersed on at least one surface of a thermoplastic resin film. It is preferable to prepare.

In this case, a chopped sheet can be easily produced by impregnating a plurality of chopped materials in a state of being dispersed on at least one surface of the thermoplastic resin film. In addition, the risk of the chopped material separating from the chopped sheet after production is reduced.

The method for manufacturing a fiber-reinforced resin fastener, further comprising a chopped sheet shredding step of shredding the chopped sheet into a predetermined size larger than the chopped material after the chopped sheet manufacturing step. In the charging step, it is preferable to pack the shredded chopped sheet into the inside of the mold.

In such a manufacturing method, a chopped sheet that is shredded to a predetermined size larger than the chopped material is packed inside the mold, so that there is no need for another work of rolling or deforming the chopped sheet before packing it inside the mold. Therefore, it is easy to put it in the mold. At the same time, it is possible to disperse the chopped material more uniformly in the space of the mold than when it is put into the mold as it is. As a result, mass productivity is further improved.

In the above-mentioned method for manufacturing a fiber-reinforced resin fastener, the fiber length of the reinforcing fiber contained in the chop material is preferably 5 to 100 mm. Within this range, it is possible to secure high strength of the fastener.

In the above-mentioned method for manufacturing a fiber-reinforced resin fastener, the volume content of the reinforcing fibers contained in the thermoplastic resin in the chop material is preferably 30 to 80%. Within this range, it is possible to secure high strength and shapeability of the fastener.

The fiber-reinforced resin fastener according to the present embodiment is a fiber-reinforced resin fastener formed of a thermoplastic resin and a reinforcing fiber impregnated in the thermoplastic resin in a state where the orientation is not specified. The fiber length of the reinforcing fiber is in the range of 5 to 100 mm, and the volume content of the reinforcing fiber in the thermoplastic resin is in the range of 30 to 80%.

In the above fastener, the orientation of the reinforcing fibers is not specified, that is, the reinforcing fibers are impregnated with the thermoplastic resin in a state where the reinforcing fibers have long fibers, and the fiber length is in the range of 5 to 100 mm as a condition for the reinforcing fibers. Since the volume content of the thermoplastic resin is in the range of 30 to 80%, it is excellent in mass productivity and has high strength.

According to the method for manufacturing a fiber-reinforced resin fastener and the fiber-reinforced resin fastener according to the present embodiment, it is possible to manufacture a fastener having excellent mass productivity and high strength.

Claims (7)

It is a method of manufacturing fasteners made of fiber reinforced plastic.
A preparatory step of preparing a plurality of chop materials in which a fiber-reinforced resin sheet impregnated with a thermoplastic resin is shredded to a predetermined size with the opened reinforcing fibers oriented in a predetermined direction.
The charging process of charging the plurality of chop materials into the mold, and
A method for manufacturing a fiber-reinforced resin fastener, which comprises a pressurizing step of forming the shape of the fastener by pressurizing the chop material inside the mold while the mold is heated. After the preparatory step, the chopped sheet manufacturing step of manufacturing the chopped sheet in which the plurality of chopped materials are arranged in a plane and united is further included.
In the charging step, the chopped sheet is packed inside the mold.
The method for manufacturing a fiber-reinforced resin fastener according to claim 1. The fiber-reinforced resin fastener according to claim 2, wherein in the chopped sheet manufacturing step, the chopped sheet is manufactured by impregnating the plurality of chopped materials in a state of being dispersed on at least one surface of a thermoplastic resin film. Manufacturing method. After the chopped sheet manufacturing step, the chopped sheet shredding step of shredding the chopped sheet into a predetermined size larger than the chopped material is further included.
In the charging step, the chopped sheet that has been shredded is packed inside the mold.
The method for manufacturing a fiber-reinforced resin fastener according to claim 2 or 3. The fiber length of the reinforcing fiber contained in the chop material is 5 to 100 mm.
The method for manufacturing a fiber-reinforced resin fastener according to any one of claims 1 to 4. The volume content of the reinforcing fibers contained in the thermoplastic resin in the chop material is 30 to 80%.
The method for manufacturing a fiber-reinforced resin fastener according to any one of claims 1 to 5. A fiber-reinforced resin fastener formed of a thermoplastic resin and a reinforcing fiber impregnated in the thermoplastic resin in a state where the orientation is not specified.
The fiber length of the reinforcing fiber is in the range of 5 to 100 mm.
The volume content of the reinforcing fibers in the thermoplastic resin is in the range of 30 to 80%.
A fiber reinforced plastic fastener characterized by this.

Images