Method for manufacturing a fiber-reinforced resin molded body and fiber-reinforced resin molded body

Abstract

A fiber-reinforced resin molded article containing a matrix resin and the recycled reinforced fibers contained therein is continuously manufactured while making effective use of recycled reinforced fibers. [Solution] The manufacturing method of the present invention includes a nonwoven fabric preparation step of preparing a nonwoven fabric (31), a mold preparation step of preparing a mold (54) having a die hole (542) extending in the longitudinal direction, and a molding step of heating the nonwoven fabric (31) to which uncured matrix resin (523) has been attached in the longitudinal direction while passing it through the die hole (542), thereby obtaining a fiber-reinforced resin molded body (1) containing the cured matrix resin (523) and the recycled reinforcing fibers (10) contained therein.

Description

Technical Field

[0001] The present invention relates to a method for producing a fiber-reinforced resin molded article containing a matrix resin and recycled reinforcing fibers contained therein, and to the fiber-reinforced resin molded article.

Background Art

[0002] Fiber-reinforced resin molded articles containing reinforcing fibers such as carbon fibers and a matrix resin are sometimes used as reinforcing materials for reinforcing products such as vehicles. Depending on circumstances, for example when a fiber-reinforced resin molded article is not used as planned, surplus fiber-reinforced resin molded articles may be generated. In order to reuse the reinforcing fibers contained in such surplus fiber-reinforced resin molded articles, it is known that the reinforcing fibers are extracted from the fiber-reinforced resin molded articles through a treatment such as heating (incineration), and the extracted reinforcing fibers are accumulated and bonded to produce a recycled reinforcing fiber nonwoven fabric.

[0003] Patent Document 1 listed below discloses a method for producing a laminate in which a plurality of recycled reinforcing fiber nonwoven fabrics (recycled carbon fiber nonwoven fabrics) are laminated as a processed product obtained by processing the aforementioned recycled reinforcing fiber nonwoven fabric. Specifically, this Patent Document 1 discloses a method for producing a laminate of recycled reinforcing fiber nonwoven fabrics by integrating a plurality of recycled reinforcing fiber nonwoven fabrics stacked in the thickness direction through a needle punching method.

Prior Art Literature

Patent Document

[0004]

Patent Document 1

Summary of the Invention

Problem to be Solved by the Invention

[0005] Patent Document 1 further discloses a method for producing a fiber-reinforced polymer (CFRP) molded article with a high fiber content (Vf) by impregnating the resulting laminate of recycled reinforced fibers with resin, inserting it into a mold, and applying high-pressure pressing. A fiber-reinforced polymer molded article with a high Vf content obtained by this method can be suitably used, for example, as a reinforcing material. However, the method described in Patent Document 1, which involves press working, requires a considerable amount of time for each press working cycle. Therefore, in order to shorten the cycle time, it is necessary to prepare a large number of press machines, and there is room for improvement in terms of productivity.

[0006] This invention has been made in view of the above circumstances, and aims to continuously manufacture fiber-reinforced resin molded articles containing a matrix resin and recycled reinforcing fibers contained therein, while making effective use of recycled reinforcing fibers. [Means for solving the problem]

[0007] To solve the above problems, a method for manufacturing a fiber-reinforced resin molded article according to one aspect of the present invention includes: a nonwoven fabric preparation step of preparing a nonwoven fabric containing recycled reinforcing fibers; a mold preparation step of preparing a mold having die holes extending in the longitudinal direction; and a molding step of obtaining a fiber-reinforced resin molded article containing the cured matrix resin and the recycled reinforcing fibers contained therein by heating the nonwoven fabric, to which uncured matrix resin is attached, while passing it through the die holes in the longitudinal direction.

[0008] According to the present invention, since a nonwoven fabric to which uncured matrix resin is attached is passed through the die hole of a molding die, a fiber-reinforced resin molded article containing the matrix resin cured by heating inside the die hole and recycled reinforcing fibers contained therein can be continuously manufactured.

[0009] Preferably, in the nonwoven fabric preparation step, a nonwoven fabric having a first thickness in the thickness direction is prepared, and in the mold preparation step, a mold having a die hole with a second thickness having a dimension in the thickness direction smaller than the first thickness is prepared.

[0010] In this embodiment, since the dimension of the die hole in the thickness direction (second thickness) is smaller than the dimension of the nonwoven fabric in the thickness direction (first thickness), the nonwoven fabric is compressed in the thickness direction within the die hole. As a result, the recycled reinforcing fibers become densely packed in the thickness direction, and the volume content of recycled reinforcing fibers (fiber volume content) in the fiber-reinforced resin molded article can be increased.

[0011] Preferably, in the nonwoven fabric preparation step, the nonwoven fabric is prepared in which a plurality of nonwoven fabric sheets containing the recycled reinforced fibers are laminated in the thickness direction.

[0012] In this embodiment, it is possible to manufacture a fiber-reinforced resin molded article having a relatively large thickness while increasing the fiber volume content.

[0013] Preferably, the uncured matrix resin contains an epoxy resin and a curing agent.

[0014] In this embodiment, after the epoxy groups in the epoxy resin react with the curing agent during the molding process, a high molecular weight three-dimensional cured product is formed, allowing the matrix resin to have high heat resistance and chemical resistance.

[0015] To solve the above problems, a fiber-reinforced resin molded article according to another aspect of the present invention is a fiber-reinforced resin molded article manufactured by the method for manufacturing a fiber-reinforced resin molded article described above, wherein the fiber volume content, which is the volume ratio of the recycled reinforcing fibers to the fiber-reinforced resin molded article, is 20% or more.

[0016] In this embodiment, sufficient strength can be ensured for the fiber-reinforced resin molded article.

[0017] To solve the above problem, a fiber-reinforced resin molded article according to another aspect of the present invention is a fiber-reinforced resin molded article produced by the method for producing a fiber-reinforced resin molded article described above, and has a tensile strength of 300 MPa or more.

[0018] The fiber-reinforced resin molded article according to this aspect can be suitably used as a reinforcing material for reinforcing products. [Effects of the Invention]

[0019] As described above, it is possible to continuously produce a fiber-reinforced resin molded article including a matrix resin and recycled reinforcing fibers contained therein, while achieving effective utilization of the recycled reinforcing fibers. [Brief Description of the Drawings]

[0020] [Figure 1] It is a perspective view showing a fiber-reinforced resin molded article according to one embodiment of the present invention. [Figure 2] It is a side view schematically showing a production apparatus for producing the above fiber-reinforced resin molded article. [Figure 3] It is a perspective view showing three sheets of recycled reinforcing fiber nonwoven fabric according to the present embodiment. [Figure 4] It is a perspective view showing a molding die according to the present embodiment. [Figure 5] It is a flowchart summarizing the production procedure of the fiber-reinforced resin molded article by the above production apparatus. [Mode for Carrying Out the Invention]

[0021] Hereinafter, preferred embodiments of the fiber-reinforced resin molded article of the present invention and the production method thereof will be described with reference to the drawings. The fiber-reinforced resin molded article of the present invention is a fiber-reinforced resin molded article comprising a matrix resin and recycled reinforcing fibers contained therein, and is continuously molded by pultrusion. The fiber-reinforced resin molded article may take various shapes, for example, may be formed into a plate shape (tape shape) extending in the longitudinal direction. The use of the fiber-reinforced resin molded article is not particularly limited, and for example, it can be used as a reinforcing material for products by being adhered to the target surface of products such as vehicles, aircraft, ships, electronic devices, medical devices, civil engineering and building materials, home appliances, and tools via an adhesive.

[0022] [Structure of Fiber-Reinforced Resin Molded Article] Figure 1 is a perspective view showing a fiber-reinforced resin molded article 1 according to an embodiment of the present invention. In addition, in Figure 1, the directional relationship will be described using mutually orthogonal XYZ orthogonal coordinates. One direction side in the X-axis direction is referred to as "+X side", and the other direction side opposite to the one direction side in the X-axis direction is referred to as "-X side". One direction side in the Y-axis direction is referred to as "+Y side", and the other direction side opposite to the one direction side in the Y-axis direction is referred to as "-Y side". One direction side in the Z-axis direction is referred to as "+Z side", and the other direction side opposite to the one direction side in the Z-axis direction is referred to as "-Z side".

[0023] Further, although the X-axis direction, the Y-axis direction and the Z-axis direction are shown in Figure 1, these directions are shown for convenience in order to explain the structure of the fiber-reinforced resin molded article 1 according to the present embodiment, and do not limit the usage mode and the like of the fiber-reinforced resin molded article 1 according to the present invention. The X-axis direction corresponds to an example of the "longitudinal direction" in the present disclosure. The Y-axis direction corresponds to an example of the "width direction" in the present invention. The Z-axis direction corresponds to an example of the "thickness direction" in the present invention.

[0024] As shown in Figure 1, the fiber-reinforced resin molded body 1 is a plate-like body having a length LL, a thickness TT, and a width WW. The thickness TT is an example of the "second thickness" in this invention. The thickness TT is the dimension of the fiber-reinforced resin molded body 1 along the Z-axis direction. The length LL is the dimension of the fiber-reinforced resin molded body 1 along the X-axis direction. In Figure 1, the length LL is short, but in this embodiment, the fiber-reinforced resin molded body 1 can be manufactured continuously, so the length LL may be long. The width WW is the dimension of the fiber-reinforced resin molded body 1 along the Y-axis direction.

[0025] Specifically, the fiber-reinforced resin molded body 1 has an upper surface 11, a lower surface 12, a front side surface 13, a rear side surface 14, a right side surface 15, and a left side surface 16. The upper surface 11 and the lower surface 12 are planes perpendicular to the Z-axis direction. The upper surface 11 and the lower surface 12 face each other in the Z-axis direction. The upper surface 11 is positioned on the +Z side of the lower surface 12.

[0026] In detail, the fiber-reinforced resin molded body 1 comprises recycled reinforcing fibers 10 and a base resin 20 containing the recycled reinforcing fibers 10.

[0027] The recycled reinforced fibers 10 are long fibers of 10 mm to 300 mm in length, or short fibers of 1 cm to 10 cm in length. The shapes of the recycled reinforced fibers 10 may be substantially the same or may be different.

[0028] Various fibers that contribute to reinforcing the fiber-reinforced resin molded body 1 can be used as the recycled reinforcing fiber 10, but carbon fiber is preferred, for example. In the case of carbon fiber, it is more preferable to use PAN (polyacrylonitrile) based carbon fiber, which has relatively high strength, as the recycled reinforcing fiber 10. Of course, pitch-based carbon fiber may also be used as the recycled reinforcing fiber 10. Furthermore, it is also possible to use fibers other than carbon fiber, such as glass fiber, ceramic fiber, aramid fiber, basalt fiber, PBO fiber (poly(p-phenylenebenzoxazole) fiber), etc., as the recycled reinforcing fiber 10.

[0029] The recycled reinforcing fibers 10 are contained in the base resin 20. The recycled reinforcing fibers 10 are widely dispersed within the base resin 20. From the viewpoint of strength, the fiber volume content (Vf) of the fiber-reinforced resin molded body 1 is preferably 10% or more, and more preferably 20% or more. If the fiber volume content (Vf) of the fiber-reinforced resin molded body 1 is less than 10%, there is a risk that the reinforcing effect of the recycled reinforcing fibers 10 cannot be fully exerted when the fiber-reinforced resin molded body 1 is used as a reinforcing material for a product.

[0030] The base resin 20 includes a thermosetting matrix resin that has been cured by heat treatment. Various thermosetting resins can be used as the matrix resin, but a three-dimensional cured product produced by the reaction of epoxy resin and a curing agent is preferred.

[0031] The epoxy resin may contain either a monofunctional epoxy resin or a polyfunctional epoxy resin. When a polyfunctional epoxy resin is included as the epoxy resin, after two or more epoxy groups in the polyfunctional epoxy resin react with the curing agent in the drawing process described later, a high molecular weight three-dimensional cured product is formed, allowing the base resin 20 to have high heat resistance and chemical resistance. The polyfunctional epoxy resin may contain a difunctional epoxy resin, a trifunctional epoxy resin, or a tetrafunctional epoxy resin, but it is more preferable to include a tetrafunctional epoxy resin. These epoxy resins may be used individually or in combination of two or more types.

[0032] Furthermore, the polyfunctional epoxy resin may contain at least one of bisphenol A type epoxy resin and bisphenol F type epoxy resin.

[0033] Examples of monofunctional epoxy resins include glycidyl compounds such as glycidyl ether compounds and glycidyl ester compounds. In this specification, "glycidyl compound" refers to all glycidyl compounds, including glycidyl compounds whose main chain consists of CC bonds, glycidyl compounds whose main chain consists of CO bonds, and glycidyl compounds whose main chain consists of both CC and CO bonds.

[0034] Specifically, the monofunctional epoxy resin is not particularly limited, but examples include butylphenyl glycidyl ether, n-butyl glycidyl ether, versatic acid glycidyl ester, styrene oxide, ethylhexyl glycidyl ether, phenyl glycidyl ether, cresyl glycidyl ether, and the like.

[0035] Furthermore, the curing agent can be a known curing agent commonly used to cure epoxy resins, such as an acid anhydride. Examples of acid anhydrides include phthalic anhydrides, maleic anhydrides, and nadic anhydrides. Examples of phthalic anhydrides include tetrahydrophthalic anhydride, endomethylenetetrahydrophthalic anhydride, and hexahydrophthalic anhydride.

[0036] Furthermore, the base resin 20 may also contain a binder resin (thermoplastic resin). As will be described in detail later, the recycled reinforced fiber nonwoven fabric 110 (see Figure 3), which is the raw material for the fiber-reinforced resin molded body 1, may contain a binder resin that adheres the recycled reinforced fibers 10 together, and the base resin 20 may contain the binder resin in the recycled reinforced fiber nonwoven fabric 110.

[0037] Furthermore, from the viewpoint of strength, the void ratio of the fiber-reinforced resin molded body 1 is preferably less than 20%. If the void ratio of the fiber-reinforced resin molded body 1 is 20% or more, when the fiber-reinforced resin molded body 1 is used as a reinforcing material for a product, the reinforcing effect of the recycled reinforcing fibers 10 may not be fully realized.

[0038] Furthermore, the bending strength of the fiber-reinforced resin molded body 1 is preferably 50 MPa or more, and more preferably 300 MPa or more. If the bending strength of the fiber-reinforced resin molded body 1 is less than 50 MPa, the fiber-reinforced resin molded body 1 may not perform adequately as a reinforcing material when used as a reinforcing material in a product.

[0039] [Manufacturing equipment] The fiber-reinforced resin molded body 1 described above can be manufactured by the following manufacturing apparatus 50. Figure 2 is a schematic side view showing the manufacturing apparatus 50 for manufacturing the fiber-reinforced resin molded body 1. As shown in Figure 2, the manufacturing apparatus 50 is a so-called pultrusion molding machine for manufacturing the fiber-reinforced resin molded body 1.

[0040] The manufacturing apparatus 50 comprises a feeder 51, a resin tank 52, a mold 54, and a take-up machine 55. The feeder 51, resin tank 52, mold 54, and take-up machine 55 are arranged in this order from the upstream side in the drawing direction. Here, the top and bottom of the manufacturing apparatus 50 are defined as shown in Figure 2, but this is not intended to limit the installation orientation of the manufacturing apparatus 50. Furthermore, the fiber-reinforced resin molded body 1 manufactured by the manufacturing apparatus 50 shown in Figure 2 will have its X-axis direction (longitudinal direction) shown in Figure 1 extend along the drawing direction.

[0041] The supply unit 51 is a device that supplies recycled reinforced fiber nonwoven fabric 110 to the resin tank 52. The recycled reinforced fiber nonwoven fabric 110 is an example of a "nonwoven sheet" in the present invention. More specifically, the supply unit 51 is a device that supplies a plurality of recycled reinforced fiber nonwoven fabrics 110 to the resin tank 52. The plurality of recycled reinforced fiber nonwoven fabrics 110 include, for example, a first recycled reinforced fiber nonwoven fabric 110a, a second recycled reinforced fiber nonwoven fabric 110b, and a third recycled reinforced fiber nonwoven fabric 110c. The first to third recycled reinforced fiber nonwoven fabrics 110a to 110c may be the same or different, but in this embodiment, the case in which the first to third recycled reinforced fiber nonwoven fabrics 110a to 110c are the same will be described.

[0042] Figure 3 is a perspective view showing a portion of three recycled reinforced fiber nonwoven fabrics 110. In Figure 3, the directional relationships are explained using mutually orthogonal XYZ Cartesian coordinates. Also, in the manufacturing apparatus 50 shown in Figure 2, the X-axis direction (longitudinal direction) of the three recycled reinforced fiber nonwoven fabrics 110 shown in Figure 3 extends along the drawing direction. As described above, the three recycled reinforced fiber nonwoven fabrics 110 (110a to 110c) are identical, so only the first recycled reinforced fiber nonwoven fabric 110a will be described here. As shown in Figure 3, the first recycled reinforced fiber nonwoven fabric 110a contains recycled reinforced fibers 10 that are bonded together.

[0043] The recycled reinforcing fibers 10 of the first recycled reinforcing fiber nonwoven fabric 110a are the same as the recycled reinforcing fibers 10 of the fiber-reinforced resin molded body 1, and are either long fibers or short fibers. The first recycled reinforcing fiber nonwoven fabric 110a may also contain a binder resin that adheres the surfaces of the recycled reinforcing fibers 10 together.

[0044] The first recycled reinforced fiber nonwoven fabric 110a is a plate-like body having a thickness Ta and a width WW that is approximately the same as the width WW of the fiber-reinforced resin molded body 1. The thickness Ta is the dimension along the Z-axis of the first recycled reinforced fiber nonwoven fabric 110a. The first recycled reinforced fiber nonwoven fabric 110a contains many spaces between the recycled reinforced fibers 10.

[0045] The composition of the second recycled reinforced fiber nonwoven fabric 110b and the third recycled reinforced fiber nonwoven fabric 110c is the same as described above. These first to third recycled reinforced fiber nonwoven fabrics 110a to 110c (recycled reinforced fiber nonwoven fabric 110) can be any nonwoven fabric containing recycled reinforced fibers 10, and the type is not particularly limited. For example, recycled reinforced fiber nonwoven fabric 110 can be obtained by bonding recycled reinforced fibers 10, which have been accumulated by an appropriate method such as a wet method or a dry method, to each other by an appropriate method such as a water entanglement method, a chemical bonding method, or a needle punching method.

[0046] As shown again in Figure 2, in this embodiment, the feeder 51 includes a plurality of discharge rollers 511 around which a plurality of recycled reinforced fiber nonwoven fabrics 110 are wound, and a guide 512 that guides the plurality of recycled reinforced fiber nonwoven fabrics 110 discharged from each discharge roller 511 to the downstream side. The plurality of discharge rollers 511 are arranged to be approximately equally spaced in the vertical direction. Each discharge roller 511 rotates to discharge the recycled reinforced fiber nonwoven fabrics 110 to the downstream side. The plurality of recycled reinforced fiber nonwoven fabrics 110 discharged from each discharge roller 511 are each guided by the guide 512 and led toward the resin tank 52 on the downstream side. By passing through the guide 512, the plurality of recycled reinforced fiber nonwoven fabrics 110 are guided so that the spacing between them narrows as they move downstream. As a result, the plurality of recycled reinforced fiber nonwoven fabrics 110 are stacked in the vertical direction (thickness direction) downstream of the guide 512 and upstream of the resin tank 52.

[0047] Figure 2 illustrates a total of three feed rollers 511 corresponding to the first to third recycled reinforced fiber nonwoven fabrics 110a to 110c described above. However, the number of feed rollers 511, or in other words, the number of recycled reinforced fiber nonwoven fabrics 110 to be laminated, can be increased or decreased as appropriate depending on the target thickness TT of the fiber-reinforced resin molded body 1 (Figure 1), the fiber volume content (Vf) of the recycled reinforced fibers 10, etc.

[0048] The resin tank 52 is a tank for impregnating the recycled reinforced fiber nonwoven fabric 110 with uncured matrix resin 523. The resin tank 52 contains, for example, a matrix resin solution containing uncured matrix resin 523, a solvent, and a curing accelerator. The uncured matrix resin 523 contains, for example, an uncured thermosetting resin and a curing agent. Preferably, the uncured matrix resin 523 contains a polyfunctional epoxy resin and tetrahydrophthalic anhydride. The curing accelerator is, for example, a tertiary amine. Multiple guide rollers 521 and 522 are arranged inside and outside the resin tank 52. The upstream guide roller 521 guides each recycled reinforced fiber nonwoven fabric 110 so that the multiple recycled reinforced fiber nonwoven fabrics 110 are introduced into the resin tank 52 after lamination. In the resin tank 52, the uncured matrix resin 523 is impregnated (adhered) to each of the multiple recycled reinforced fiber nonwoven fabrics 110. This forms a resin-impregnated nonwoven fabric 31. In other words, the resin-impregnated nonwoven fabric 31 is a laminate of multiple recycled reinforced fiber nonwoven fabrics 110 impregnated with matrix resin 523. The downstream guide roller 522 leads this resin-impregnated nonwoven fabric 31 downstream of the resin tank 52 and guides it toward the mold 54. Specifically, in this embodiment, the resin-impregnated nonwoven fabric 31 is formed by laminating the first to third recycled reinforced fiber nonwoven fabrics 110a to 110c and introducing them into the resin tank 52, thereby forming a laminate of three recycled reinforced fiber nonwoven fabrics 110a to 110c impregnated with matrix resin 523.

[0049] Here, the total thickness of the first to third recycled reinforced fiber nonwoven fabrics 110a to 110c, which are laminated upstream of the mold 54 as described above, is denoted as TS (Figure 3). The thickness TS corresponds to three times the thickness Ta of each recycled reinforced fiber nonwoven fabric 110a to 110c (Ta × 3). The thickness TS is an example of the "first thickness" in this invention. The thickness TS (first thickness) is greater than the thickness TT (second thickness) of the fiber-reinforced resin molded body 1.

[0050] Multiple guides 530 are positioned upstream of the mold 54. The multiple guides 530 guide the resin-impregnated nonwoven fabric 31 so that it is introduced into the die hole 542 (see Figure 4) of the mold 54, which will be described later.

[0051] Figure 4 is a perspective view showing the mold 54 according to this embodiment. In Figure 4, the directional relationships will be explained using mutually orthogonal XYZ Cartesian coordinates. In the manufacturing apparatus 50 shown in Figure 2, the X-axis direction of the mold 54 shown in Figure 4 will extend along the pulping direction. As shown in Figures 2 and 4, the mold 54 is a mold that receives and heats the resin-impregnated nonwoven fabric 31. The mold 54 comprises a die 541 having die holes 542 inside and a heating device (not shown).

[0052] The die hole 542 penetrates the die 541 in the X-axis direction. The shape of the die hole 542 corresponds to the shape of the fiber-reinforced resin molded body 1, and the cross-section of the die hole 542 is rectangular. Specifically, the die hole 542 has an upper surface 543, a lower surface 544, a right side surface 546, and a left side surface 547. The distance between the upper surface 543 and the lower surface 544 is the thickness TT. The distance between the right side surface 546 and the left side surface 547 is the width WW.

[0053] The heating device raises the temperature of the inner wall of the die hole 542. The heating device heats the resin-impregnated nonwoven fabric 31 to which the uncured matrix resin 523 is attached, at least downstream of the mold 54, until the temperature of the uncured matrix resin 523 exceeds its curing temperature (for example, the reaction temperature between the epoxy resin and the curing agent). That is, the heating inside the mold 54 causes the uncured matrix resin 523 to cure (the epoxy resin and curing agent react). The resin-impregnated nonwoven fabric 31 in the die hole 542 is shaped by heating with the heating device to have a cross-sectional shape corresponding to the die hole 542. This produces a fiber-reinforced resin molded body 1 having a thickness TT (see Figure 1). That is, the fiber-reinforced resin molded body 1 includes a plurality of recycled reinforced fiber nonwoven fabrics 110 supplied from the delivery roller 511 of the feeder 51. As multiple recycled reinforced fiber nonwoven fabrics 110 pass through the resin tank 52 and the mold 54, the uncured matrix resin 523 adheres to the recycled reinforced fibers 10 and hardens, thereby forming a fiber-reinforced resin molded body 1. In other words, the fiber-reinforced resin molded body 1 comprises recycled reinforced fibers 10 and a base resin 20 derived from the uncured matrix resin 523.

[0054] As shown again in Figure 2, the take-up machine 55 is a device that takes up the fiber-reinforced resin molded body 1 discharged from the mold 54 and sends it further downstream. In this embodiment, the take-up machine 55 includes a plurality of pairs of rollers 551 and a pair of endless belts 552 that are arranged opposite each other vertically and wrapped around the rollers 551. However, the take-up machine 55 is not limited to one using such endless belts 552, and any type of take-up machine that is appropriate to the shape of the fiber-reinforced resin molded body 1, such as a clamp type, can be used.

[0055] [Manufacturing method] Figure 5 is a flowchart summarizing the manufacturing procedure for the fiber-reinforced resin molded body 1 using the manufacturing apparatus 50 described above. As shown in Figure 5, the manufacturing method for the fiber-reinforced resin molded body 1 generally includes a mold preparation step S101, a nonwoven fabric preparation step S102, an adhesion step S103, and a drawing step S104.

[0056] The mold preparation step S101 is a step of preparing the mold 54. The mold 54 has a die hole 542 that extends in the X-axis direction and has a thickness TT.

[0057] The nonwoven fabric preparation step S102 is a step of laminating multiple recycled reinforced fiber nonwoven fabrics 110. The nonwoven fabric preparation step S102 is carried out by a feeder 51. Specifically, a laminate of recycled reinforced fiber nonwoven fabric 110 having a thickness TS (= Ta × 3) is prepared by laminating a first recycled reinforced fiber nonwoven fabric 110a, a second recycled reinforced fiber nonwoven fabric 110b, and a third recycled reinforced fiber nonwoven fabric 110c.

[0058] The adhesion process S103 is a process in which a laminate of recycled reinforced fiber nonwoven fabric 110 is passed through a resin tank 52 to impregnate the recycled reinforced fiber nonwoven fabric 110 with uncured matrix resin 523, thereby obtaining resin-impregnated nonwoven fabric 31. The adhesion process S103 is realized by the resin tank 52 and the guide rollers 521 and 522 before and after it.

[0059] The drawing process S104 is a process to obtain a fiber-reinforced resin molded body 1 having a thickness TT by heating the resin-impregnated nonwoven fabric 31 while drawing it through the die hole 542 of the mold 54 in the drawing direction (X-axis direction). The drawing process S104 is carried out by the mold 54 and the draw machine 55.

[0060] Through the processes S101 to S104 described above, a fiber-reinforced resin molded article 1, schematically shown in Figure 1, is manufactured. That is, a fiber-reinforced resin molded article 1 containing recycled reinforced fibers 10 and a base resin 20 (matrix resin) is manufactured. Note that the adhesion process and the drawing process correspond to the "molding process" in this invention.

[0061] [Effects and Effects] As described above, in this embodiment, since the recycled reinforced fiber nonwoven fabric 110 (first to third recycled reinforced fiber nonwoven fabrics 110a to 110c) to which the uncured matrix resin 523 is attached is passed through the die hole 542 of the mold 54, a fiber-reinforced resin molded body 1 containing the matrix resin cured by heating in the die hole 542 and the recycled reinforced fibers 10 contained therein can be continuously manufactured. Furthermore, in this embodiment, since the thickness TT of the die hole 542 is smaller than the thickness TS of the recycled reinforced fiber nonwoven fabric 110, the recycled reinforced fiber nonwoven fabric 110 is compressed in the thickness direction (Z-axis direction) within the die hole 542, resulting in the recycled reinforced fibers 10 becoming densely packed in the thickness direction, and the volume content of recycled reinforced fibers 10 (fiber volume content) in the fiber-reinforced resin molded body 1 can be increased.

[0062] Furthermore, in this embodiment, since multiple (3) recycled reinforced fiber nonwoven fabrics 110 with a total thickness of TS are passed through the die holes 542, it is possible to manufacture a fiber-reinforced resin molded body 1 with a relatively large thickness while increasing the fiber volume content. Therefore, when the fiber-reinforced resin molded body 1 is used as a reinforcing material, the reinforcing effect of the fiber-reinforced resin molded body 1 can be enhanced.

[0063] [Differentiation] Although preferred embodiments of the present invention have been described above, the present invention is not limited to the above embodiments, and the following modifications are possible, for example.

[0064] (1) In the above embodiment, the fiber-reinforced resin molded body 1 is manufactured from a plurality of (for example, three) recycled reinforced fiber nonwoven fabrics 110 supplied from the feeder 51, but the invention is not limited to this method. For example, the fiber-reinforced resin molded body 1 may be manufactured from a single recycled reinforced fiber nonwoven fabric 110. In this case, the thickness Ta of one recycled reinforced fiber nonwoven fabric 110 corresponds to the "first thickness" in the present invention.

[0065] (2) In the above embodiment, the multiple recycled reinforced fiber nonwoven fabrics 110 were passed through the resin tank 52 in a laminated state. However, the multiple recycled reinforced fiber nonwoven fabrics 110 may be laminated together inside the resin tank 52, or the multiple recycled reinforced fiber nonwoven fabrics 110 may be laminated together after passing through the resin tank 52. In other words, the step of laminating the multiple recycled reinforced fiber nonwoven fabrics 110 (nonwoven fabric preparation step) and the step of passing the multiple recycled reinforced fiber nonwoven fabrics 110 through the resin tank 52 (adhesion step) may be performed in this order, in the reverse order, or simultaneously.

[0066] (3) In the above embodiment, the matrix resin 523 was attached to each of the recycled reinforced fiber nonwoven fabrics 110 by passing them through a resin tank 52 storing the uncured matrix resin 523. However, the method of attaching the uncured matrix resin 523 is not limited to this. For example, the matrix resin 523 may be attached to the multiple recycled reinforced fiber nonwoven fabrics 110 inside the mold 54 by injecting the uncured matrix resin 523 into the upstream part of the mold 54. In other words, the apparatus for attaching the uncured matrix resin 523 to the multiple recycled reinforced fiber nonwoven fabrics 110 (resin attachment apparatus) can be any apparatus that can supply the matrix resin 523 so that the uncured matrix resin 523 attaches to the multiple recycled reinforced fiber nonwoven fabrics 110 in or upstream of the mold 54, and the resin tank 52 is merely one example.

[0067] (4) In the above embodiment, a plate-shaped fiber-reinforced resin molded body 1 having a rectangular cross-section was manufactured by passing a nonwoven fabric 31 through a mold 54 having a die hole 542 with a rectangular cross-section. However, the manufacturing method of the present invention can also be applied to the manufacture of fiber-reinforced resin molded bodies 1 having various cross-sectional shapes other than rectangles, such as polygons and circles. [Examples]

[0068] <Example 1> First, in the mold preparation process, a mold with a die hole having a thickness of 1.0 mm and a width of 20.0 mm was prepared. Next, in the nonwoven fabric preparation process, eight sheets of recycled reinforced fiber nonwoven fabric containing PAN (polyacrylonitrile) carbon fibers were laminated to produce a nonwoven fabric with a thickness of Ta × 8 and a width of 20.0 mm (density 1.8 g / cm³). 2 Weight: 100g / cm 2 A nonwoven fabric was prepared. Next, in the adhesion step, a nonwoven fabric was passed through a resin tank containing a first matrix resin solution containing 70% by mass of polyfunctional epoxy resin ("jER604" manufactured by Mitsubishi Chemical Corporation), 30% by mass of polyfunctional epoxy resin ("Denacol® EX-321" manufactured by Nagase ChemteX Corporation), 132% by mass of tetrahydrophthalic anhydride ("HN-2200" manufactured by Resonaq Corporation), and a solvent, thereby obtaining a nonwoven fabric impregnated with polyfunctional epoxy resin and curing agent. Finally, in the drawing step, the nonwoven fabric impregnated with polyfunctional epoxy resin and curing agent was heated to 200°C while being drawn through the die holes. This obtained a fiber-reinforced resin molded article according to Example 1. The fiber-reinforced resin molded body according to Example 1 was a plate-like body with a thickness of 1.0 mm and a width of 20.0 mm. The fiber volume content (Vf) of the fiber-reinforced resin molded body according to Example 1 was 39.1%, and the void ratio was 0.5%.

[0069] <Example 2> Except for changing the number of layers of recycled reinforced fiber nonwoven fabric from eight to six, the same manufacturing method as in Example 1 was employed, thereby obtaining the fiber-reinforced resin molded article according to Example 2. The fiber-reinforced resin molded article according to Example 2 is a plate-like body with a thickness of 1.0 mm and a width of 20.0 mm. The fiber volume content (Vf) of the fiber-reinforced resin molded article according to Example 2 was 29.5%, and the void ratio was 1.2%.

[0070] <Example 3> Except for changing the number of layers of recycled reinforced fiber nonwoven fabric from eight to four, the same manufacturing method as in Example 1 was employed, thereby obtaining the fiber-reinforced resin molded body according to Example 3. The fiber-reinforced resin molded body according to Example 3 is a plate-like body with a thickness of 1.0 mm and a width of 20.0 mm, and the fiber volume content (Vf) of the fiber-reinforced resin molded body according to Example 3 was 21.4%, and the void ratio was 3.7%.

[0071] <Example 4> Except for changing the number of layers of recycled reinforced fiber nonwoven fabric from eight to five and changing the first matrix resin solution to the second matrix resin solution shown below, the same manufacturing method as in Example 1 was adopted, thereby obtaining the fiber-reinforced resin molded article according to Example 4. The second matrix resin solution contains 80% by mass of bisphenol A type epoxy resin (DIC Corporation's "EPICLON850®"), 20% by mass of monofunctional epoxy resin (p-tert-butylphenyl glycidyl ether, Nagase ChemteX Corporation's "Denacol® EX-146"), 85% by mass of tetrahydrophthalic anhydride (Resonac Corporation's "HN-2200"), and 2% by mass of tertiary amine curing agent "Ancamin K54" (Resonac Corporation). The fiber-reinforced resin molded body according to Example 4 was a plate-like body with a thickness of 1.0 mm and a width of 20.0 mm. The fiber volume content (Vf) of the fiber-reinforced resin molded body according to Example 4 was 28.4%, and the void ratio was 0.9%.

[0072] <Example 5> Except for changing the number of layers of recycled reinforced fiber nonwoven fabric from five to four, the same manufacturing method as in Example 4 was employed, thereby obtaining the fiber-reinforced resin molded body according to Example 5. The fiber-reinforced resin molded body according to Example 5 is a plate-like body having a thickness of 1.0 mm and a width of 20.0 mm, and the fiber volume content (Vf) of the fiber-reinforced resin molded body according to Example 5 was 21.8%, and the void ratio was 2.9%.

[0073] <Comparative Example 1> Unlike Examples 1-5, which were manufactured using a pultrusion machine, Comparative Example 1 was manufactured using a press machine. Specifically, in Comparative Example 1, a laminate consisting of five sheets of recycled reinforced fiber nonwoven fabric laminated with an uncured matrix resin attached was placed in a mold, and a predetermined pressing pressure was applied by a punch to obtain a fiber-reinforced resin molded article. The matrix resin used in Comparative Example 1 was the same as in Examples 1-3. The fiber-reinforced resin molded article in Comparative Example 1 was a plate-like body with a thickness of 1.0 mm and a width of 20.0 mm, and the fiber volume content (Vf) of the fiber-reinforced resin molded article in Comparative Example 1 was 30.1%, and the void ratio was 1.0%.

[0074] <Evaluation Method> Tensile strength and modulus of elasticity of fiber-reinforced resin molded articles Using the fiber-reinforced resin molded articles from Examples 1 to 5 and Comparative Example 1, test specimens measuring 15 mm in width, 250 mm in length, and 1.0 mm in thickness were prepared in accordance with JIS K7164. The tensile strength and elastic modulus of the fiber-reinforced resin molded articles from Examples 1 to 5 and Comparative Example 1 were measured using a testing machine. The tensile strength and elastic modulus are shown in Table 1.

[0075] [Table 1] <Evaluation Results> As shown in Table 1, when a polyfunctional epoxy resin was used as the matrix resin (Examples 1-3), the fiber volume content and tensile strength were greater in Example 1, Example 2, and Example 3, in that order. Specifically, the fiber volume content and tensile strength of Example 2 were greater than those of Example 3, and the fiber volume content and tensile strength of Example 1 were greater than those of Example 2. Furthermore, when a combination of bisphenol A type epoxy resin and monofunctional epoxy resin was used as the matrix resin (Examples 4 and 5), the fiber volume content and tensile strength were greater in Example 4 than in Example 5. From this, it was found that, under the same matrix resin conditions, increasing the number of recycled reinforced fiber nonwoven fabrics improves the fiber volume content (Vf) of the fiber-reinforced resin molded body, and further improves the tensile strength and elastic modulus of the fiber-reinforced resin molded body.

[0076] The fiber volume content of Examples 1 to 5 was 20% or more in all cases. Regarding tensile strength, the tensile strength of Examples 1, 2, 4, and 5 was 300 MPa or more in all cases, which is greater than the tensile strength of Comparative Example 1 (288.3 MPa). In contrast, the tensile strength of Example 3 was lower than that of Comparative Example 1.

[0077] Of Examples 1 to 3, in which the matrix resin is the same polyfunctional epoxy resin as in Comparative Example 1, Examples 1 and 2 exhibit higher tensile strength than Comparative Example 1. The fiber volume content of Examples 1 and 2 is 29% or more. In other words, the fiber-reinforced resin molded articles according to Examples 1 and 2, which had a fiber volume content of 29% or more, exhibited a tensile strength of 300 MPa or more, which is higher than the fiber-reinforced resin molded article according to Comparative Example 1, which used the same polyfunctional epoxy resin as in Examples 1 and 2.

[0078] The fiber volume content of the fiber-reinforced resin molded article in Example 2 (29.5%) was almost the same as that of the fiber-reinforced resin molded article in Comparative Example 1, which used the same polyfunctional epoxy resin as in Example 2 (30.1%). However, the tensile strength of the fiber-reinforced resin molded article in Example 2 (328.1 MPa) was greater than that of the fiber-reinforced resin molded article in Comparative Example 1 (288.3 MPa).

[0079] The tensile strength of the fiber-reinforced resin molded article in Example 3 (244.8 MPa) is lower than that of the fiber-reinforced resin molded article in Comparative Example 1 (288.3 MPa). However, the difference is not significant, indicating that a fiber-reinforced resin molded article of comparable quality can be obtained even with continuous molding using a pultrusion machine. [Explanation of Symbols]

[0080] 1. Fiber-reinforced resin molded body 10 Recycled reinforced fibers 20 Base resin 31 Nonwoven fabric 52 Resin tank 54 Molding mold 110 Recycled reinforced fiber nonwoven fabric (nonwoven sheet) 542 die holes S101 Molding mold preparation process S102 Nonwoven fabric preparation process S103 Adhesion process (molding process) S104 Drawing process (forming process)

Claims

1. A nonwoven fabric preparation process that prepares nonwoven fabric containing recycled reinforced fibers, A mold preparation step in which a mold having a die hole extending in the longitudinal direction is prepared, A method for producing a fiber-reinforced resin molded article, comprising: a molding step of heating the nonwoven fabric, to which uncured matrix resin is attached, while passing it through the die hole in the longitudinal direction, thereby obtaining a fiber-reinforced resin molded article containing the cured matrix resin and the recycled reinforcing fibers contained therein.

2. In the method for producing a fiber-reinforced resin molded article according to claim 1, In the nonwoven fabric preparation step, a nonwoven fabric is prepared in which the dimension in the thickness direction is a first thickness. A method for manufacturing a fiber-reinforced resin molded article, wherein in the mold preparation step, a mold is prepared having a die hole whose dimension in the thickness direction is smaller than the first thickness.

3. In the method for producing a fiber-reinforced resin molded article according to claim 2, A method for manufacturing a fiber-reinforced resin molded article, wherein the nonwoven fabric preparation step involves preparing a nonwoven fabric in which a plurality of nonwoven fabric sheets containing the recycled reinforcing fibers are laminated in the thickness direction.

4. In a method for manufacturing a fiber-reinforced resin molded article according to any one of claims 1 to 3, The method for producing a fiber-reinforced resin molded article, wherein the uncured matrix resin contains an epoxy resin and a curing agent.

5. A fiber-reinforced resin molded article manufactured by the method for manufacturing a fiber-reinforced resin molded article described in any one of claims 1 to 3, A fiber-reinforced resin molded body in which the volume ratio of recycled reinforcing fibers to the fiber-reinforced resin molded body is 20% or more.

6. A fiber-reinforced resin molded article manufactured by the method for manufacturing a fiber-reinforced resin molded article described in any one of claims 1 to 3, A fiber-reinforced resin molded article having a tensile strength of 300 MPa or more.

Images