JP7625819B2 - Method for producing fiber-reinforced molding - Google Patents

Description

The present invention relates to a method for producing a fiber-reinforced molding. More specifically, the present invention relates to a method for producing a fiber-reinforced molding having a core material containing reinforcing fibers and a matrix resin in which the core material is embedded.

Conventionally, methods for producing fiber-reinforced molded bodies include the RTM (Resin Transfer Molding) method and the Vacuum Assisted Resin Transfer Molding (VaRTM) method (see Patent Document 1). These methods involve placing a woven fabric containing reinforcing fibers in the cavity of a mold, injecting uncured resin into the cavity to impregnate the woven fabric with the uncured resin, and then curing the uncured resin to obtain a fiber-reinforced molded body. The VaRTM method differs from the RTM method in that it involves an operation of degassing the cavity to assist the impregnation of the uncured resin.

JP 2015-186884 A

Although the RTM method and VaRTM method as described above have the advantage of being suitable for mass production, they have the problem that it is difficult to produce a molded body having a three-dimensional shape, i.e., a complex three-dimensional shape. That is, a woven fabric containing reinforcing fibers is originally a flat two-dimensional shape, and it is difficult to shape it into a complex three-dimensional shape by molding. Therefore, the above-mentioned Patent Document 1 discloses a method of using a core material 7 in the RTM method. This method is excellent for fiber-reinforced molded bodies with a linear shape in the longitudinal direction of the core material 7, but it is difficult to make the core material 7 into a branched shape, for example.

For these reasons, fiber-reinforced molded bodies with complex shapes are often realized by integrating multiple parts that have been manufactured separately. However, when integrating parts manufactured separately, there is a problem that the structure tends to become complicated in order to obtain strength at the joints. Furthermore, in fiber-reinforced molded bodies such as skeletal structures formed by combining reinforcing structures of different shapes, the strength at the joints decreases, making it difficult to obtain a well-balanced reinforcing structure.

The present invention was made in consideration of the above-mentioned circumstances, and aims to provide a method for manufacturing a fiber-reinforced molding that can prevent the need to manufacture each part separately when manufacturing a fiber-reinforced molding having a complex three-dimensional shape.

That is, in order to solve the above problems, the present invention is presented below.
[1] The method for producing a fiber-reinforced molding of the present invention is a method for producing a fiber-reinforced molding having a core material containing reinforcing fibers and a matrix resin in which the core material is embedded,
a fixing step of fixing the fiber aggregate serving as the core material along a peripheral surface of a middle mold (such as a core);
The method also includes a removal step of embedding the fixed fiber aggregate in the matrix resin, and then dismantling, deforming or reducing the volume of the central mold to remove the fiber-reinforced molding.
[2] In the method for producing a fiber-reinforced molding of the present invention, the fiber aggregate has a fiber bundle obtained by bundling continuous fibers including the reinforcing fibers, and a base layer to which the fiber bundle is sewn,
The fiber bundles may have strips sewn onto the base layer so as to be arranged in double rows.
[3] In the method for producing a fiber-reinforced molding of the present invention, the fixing step may include a step of winding the belt-shaped portion around the peripheral surface of the middle mold.
[4] In the method for producing a fiber-reinforced molding of the present invention, the middle mold may have a recess on its peripheral surface that accommodates the thickness of the fiber aggregate.
[5] In the method for producing a fiber-reinforced molding of the present invention, the center die may have a protrusion on the peripheral surface thereof that engages with a through hole provided in the fiber aggregate.
[6] In the method for producing a fiber-reinforced molding of the present invention, the fixing step can be carried out by driving a fastening device from the outer surface side of the fiber assembly aligned along the peripheral surface of the middle mold toward the middle mold.
[7] In the method for producing a fiber-reinforced molding of the present invention, the intermediate mold is formed from a dismantlable material,
The material may be selected from a bound material in which particulate matter is bound with a binder, and a coagulated material in which particulate matter is agglomerated.
[8] In the method for producing a fiber-reinforced molding of the present invention, the inner mold is made of a material that can be heated and melted,
The material may be a thermoplastic composition.
[9] In the method for producing a fiber-reinforced molding of the present invention, the fiber-reinforced molding has a plurality of reinforcing holes for forming a reinforcing structure, including two adjacent reinforcing holes _H1 and _H2 ,
The opening surface of the reinforcing hole _H1 and the opening surface of the reinforcing hole _H2 may belong to different planes.

According to the method for producing a fiber-reinforced molding of the present invention, when producing a fiber-reinforced molding having a complex three-dimensional shape, it is possible to avoid producing each part separately.
More specifically, while enjoying the advantage of being suitable for mass production associated with the RTM method and the VaRTM method, a more complex fiber-reinforced molded body (e.g., a skeletal structure with a reinforcement structure) can be manufactured in one piece, without being manufactured separately, as compared to the conventional method. Therefore, the fiber-reinforced molded body can be efficiently manufactured by suppressing the generation of connection points. In addition, since the generation of connection points can be suppressed, a fiber-reinforced molded body in which the complexity of the shape required for connection and the increase in weight are suppressed can be obtained. In addition, a fiber-reinforced molded body with a smoother shape and a uniform strength balance can be obtained. Furthermore, an opening reinforcement structure that could be realized by obtaining a molded body without holes and then drilling holes in the necessary places in the conventional method can be obtained with a low man-hour without performing a hole drilling process.

The present invention will be further described in the following detailed description by way of non-limiting examples of exemplary embodiments according to the invention and with reference to the several drawings mentioned, in which like reference numerals refer to like parts throughout the several views of the drawings.
FIG. 2 is an explanatory diagram illustrating an example of a method for producing a fiber-reinforced molding of the present invention. FIG. 2 is an explanatory diagram illustrating an example of a fiber aggregate. FIG. 2 is an explanatory diagram illustrating a sewing mode of a sewn-type fiber aggregate. FIG. 2 is an explanatory diagram illustrating a sewing mode of a sewn-type fiber aggregate. FIG. 13 is an explanatory diagram illustrating a fixing step. FIG. 2 is an explanatory diagram illustrating an example of a fiber-reinforced molding. FIG. 2 is an explanatory diagram illustrating an example of a fiber-reinforced molding. FIG. 2 is an explanatory diagram illustrating an example of a fiber-reinforced molding. FIG. 4 is an explanatory diagram illustrating another example of a fiber-reinforced molding.

The matters shown herein are for illustrative purposes and are intended to provide an illustrative description of the embodiments of the present invention, with the aim of providing what is believed to be the most effective and easily understandable explanation of the principles and conceptual features of the present invention. In this respect, it is not intended to show structural details of the present invention beyond the extent necessary for a fundamental understanding of the present invention, and the description, taken together with the drawings, will make clear to those skilled in the art how some forms of the present invention may be actually embodied.
In addition, in Fig. 2(b), the sewing thread 175 is illustrated, but in other figures, the sewing thread 175 is omitted from illustration to avoid complication. Also, Fig. 1(a) in the drawings will be referred to as Fig. 1(a) or Fig. 1a in the specification.

The method for producing a fiber-reinforced molding of the present invention is a method for producing a fiber-reinforced molding (1) having a core material (13) containing reinforcing fibers (12) and a matrix resin (15) in which the core material (13) is embedded (see Figures 1 and 9).
This manufacturing method includes a fixing step (R1) and a removal step (R2).
Among these, the fixing step (R1) is a step of fixing the fiber aggregate (14) that will become the core material (13) along the peripheral surface (201) of the middle mold (20).
The removal step (R2) is a step of embedding the fixed fiber aggregate (14) in the matrix resin (15), and then dismantling, deforming or reducing the volume of the middle mold (20) to remove the fiber-reinforced molding (1).

[1] Fixing Step The fixing step R1 is a step of fixing the fiber aggregate 14 that will become the core material 13 along the peripheral surface 201 of the middle mold 20 (see Figs. 1a, 1b, and 1c).
(1) Core material and fiber aggregate The core material 13 is a part that reinforces the matrix resin 15 in the fiber-reinforced molding 1, and is formed from an aggregate of fibers. That is, the matrix resin 15 is impregnated into the core material 13 and fixed (cured, solidified, etc.) in a state where it is impregnated into the inside of the core material 13, resulting in a fiber-reinforced molding 1 that has high strength overall. Therefore, compared to a resin member consisting of only the matrix resin 15, the addition of the core material 13 in the resin increases the mechanical strength of the fiber-reinforced molding 1.
In this specification, the fiber aggregate that constitutes a part of the fiber-reinforced molding 1 is referred to as the core material 13, and the core material 13 before the fiber-reinforced molding 1 is completed is referred to as the fiber aggregate 14. As described above, the core material 13 and the fiber aggregate 14 are basically the same thing, so the following description will use the fiber aggregate 14, but the same applies to the core material 13.

The form of the fiber assembly 14 is not limited, and may be, for example, a nonwoven fabric, a woven fabric, a knitted fabric, a fiber bundle (tow), or a combination thereof.
Among the above, the fiber bundle 17 is in the form of a bundle of continuous fibers 171, and contains the reinforcing fibers 12 as part or all of the continuous fibers 171. The fiber bundle 17 may be formed only from the reinforcing fibers 12, or may contain fibers 172 other than the reinforcing fibers.
Among the above, the composite form is a form in which two or more of nonwoven fabric, woven fabric, knitted fabric, and fiber bundle are combined. Specifically, a form in which a fiber bundle is fixed to a base layer can be mentioned. The fixing means is not limited, and for example, one or more of means such as sewing, adhesion, and fusion can be adopted. That is, the fiber assembly 14 can have a fiber bundle 17 and a base layer 18 to which the fiber bundle 17 is sewn, and the fiber bundle 17 can be sewn onto the base layer 18. The fiber bundle 17 may be sewn to only one surface of the base layer 18, or may be sewn to both surfaces of the base layer 18.

In the sewn-type fiber assembly 14, one or more of nonwoven fabric, woven fabric, knitted fabric, etc. may be used as the base layer. That is, for example, the fiber bundles 17 may be sewn to a base layer 18 made of woven fabric, or the fiber bundles 17 may be sewn to a base layer 18 made of nonwoven fabric (see FIG. 2).
In this manner, in the fiber aggregate 14 in which the fiber bundles 17 are sewn to the base layer 18 (hereinafter, the fiber aggregate 14 in this form is also referred to as a "sewn-type fiber aggregate") (see Figs. 2 and 4), the fiber bundles 17 are sewn to the base layer 18 by a sewing thread 175. Any fiber may be used for the sewing thread 175. That is, the same fiber as the reinforcing fiber described below may be used, or a fiber other than the reinforcing fiber may be used.

Of the above, the base layer 18 in the sewn-type fiber aggregate 14 is preferably a woven fabric. Woven fabrics have the advantages of being easy to sew the fiber bundles 17 to, having high restraint on the sewing thread 175 when sewn, excellent flexibility as the base layer 18, and being easy to impregnate with matrix resin (unsolidified material). When the base layer 18 is a woven fabric, any fiber may be used as the fiber that constitutes this fabric. That is, fibers similar to the reinforcing fibers described below may be used, or fibers other than the reinforcing fibers may be used.

Furthermore, in the sewn-type fiber assembly 14, the shape of the base layer 18 usually determines the overall shape of the fiber assembly 14. For example, if the base layer 18 has a belt-like portion 141, the fiber assembly 14 can also have a belt-like portion 141 depending on the shape of the base layer 18 (see Figs. 1, 2 and 5).
In addition, as described above, the sewn-type fiber aggregate 14 can have an area (sewn area) where the fiber bundles 17 are sewn to the base layer 18, but can also have an area (non-sewn area) where the fiber bundles 17 are not sewn to the base layer 18 but are arranged so as to be spaced apart from the base layer 18.

As described above, when sewing is selected as a means for fixing the fiber bundles 17 to the base layer 18, the degree of restraint of the fiber bundles 17 can be freely controlled by the tension of the sewing thread 175. Therefore, while the fiber bundles 17 are firmly fixed to the base layer 18, the mobility of the fiber bundles 17 (the mobility relative to the base layer 18 and/or the mobility between the fiber bundles 17) can be ensured to a greater extent than in a woven fabric made by weaving fiber bundles. As a result, for example, the flexibility of the fiber aggregate 14 in the sewing area can be maintained at a high level.

Furthermore, in the sewing region, the fiber bundles 17 may be sewn in any manner, but may be arranged in a planar manner so as to be aligned in double rows on the base layer 18. More specifically, a plurality of fiber bundles 17 may be aligned and sewn together so as to fill a specific surface (see FIG. 3a). Furthermore, the fiber bundles 17 may be folded and sewn together so as to fill a specific surface. More specifically, one fiber bundle 17 may be folded and arranged in an accordion-like manner (see FIG. 3b). Also, the fiber bundles 17 may be folded and arranged by winding them in a spiral shape (circular spiral, polygonal spiral, etc.) (see FIG. 3c). Only one of these sewing modes may be used, or two or more may be used in combination. Needless to say, sewing modes other than these may also be used.

The fiber bundles 17 may be sewn to the base layer 18 in a single layer (see FIG. 4a), or in multiple layers (see FIG. 4b and FIG. 4c). They may also be sewn to the front and back of the base layer 18. When sewing to two or more layers or when sewing to the front and back, the fiber bundles 17 constituting one layer may be arranged in parallel to the fiber bundles 17 constituting the adjacent other layer, but they may be arranged to cross each other so that their arrangement directions are different (see FIG. 4b and FIG. 4c). In this case, the crossing angle may be 90 degrees or less (0 degrees < θ ≦ 90 degrees).

Furthermore, as described above, the core material 13 contains reinforcing fibers 12 (see FIG. 2b). That is, the fiber aggregate 14 also contains reinforcing fibers 12. The fiber aggregate 14 may contain reinforcing fibers 12 in any part. That is, for example, the fiber aggregate 14 may contain reinforcing fibers 12 as the sewing thread 175 or as the base layer 18, but it is particularly preferable that the fiber aggregate 14 contains reinforcing fibers 12 as the fiber bundles 17.

The reinforcing fibers 12 are fibers having superior mechanical strength compared to ordinary fibers, and for example, fibers having a tensile strength of 7 cN/dtex or more (usually 50 cN/dtex) according to JIS L1015 are preferable.
The reinforcing fiber 12 may be a fiber made of an inorganic material, a fiber made of an organic material, or a fiber made of a combination of these. Examples of inorganic material fibers include carbon fiber (PAN-based carbon fiber, pitch-based carbon fiber), glass fiber, metal fiber, etc. These may be used alone or in combination of two or more types. Examples of organic material fibers include aromatic polyamide resin fibers (para-aramid: trade name "Kevlar", trade name "Twaron", trade name "Technora", etc., meta-aramid: trade name "Nomex", trade name "Conex", etc.), polybenzazole resin fibers (polyparaphenylene benzobisoxazole fibers, trade name "Zylon", etc.), aromatic polyester resin fibers (trade name "Vectran", etc.), high-strength polyethylene resin fibers (trade name "Dyneema"), etc. These may be used alone or in combination of two or more types.

The fiber form of the reinforcing fiber 12 is not limited, and may be a spun yarn, a filament yarn, or a combination of these, but among these, a filament yarn is preferable. Furthermore, the reinforcing fiber 12 may be a monofilament, a multifilament, or a combination of these.

The fiber aggregate 14 may be composed entirely of reinforcing fibers 12, or may partially contain reinforcing fibers 12. The composition ratio of reinforcing fibers 12 is not limited, but the content ratio of reinforcing fibers 12 can be 50% by mass or more (or 100% by mass) relative to 100% by mass of all constituent fibers constituting the fiber aggregate 14. It can be 75% by mass or more, or 90% by mass or more. In other words, when the fiber aggregate 14 contains fibers other than reinforcing fibers, the other fibers can be less than 50% by mass (1% by mass or more), less than 25% by mass, or less than 10% by mass, when the entire constituent fibers are taken as 100% by mass.

The material of the fibers other than the reinforcing fibers 12 is not limited, and fibers other than the reinforcing fibers described above can be used. Specifically, various resin fibers and vegetable fibers can be used, and among these, polyamides (aliphatic polyamides, etc.), polyesters (polyesters having structural units derived from aromatic dicarboxylic acids, etc.) can be used as the resins constituting the resin fibers. In addition, cotton fibers and hemp fibers can be used as the vegetable fibers.
The fiber form of the other fibers is not limited either, and may be spun yarn, filament yarn, or a combination of these.

Furthermore, the fiber bundle 17 may be bundled in any manner. It may be in a state where multiple continuous fibers are simply pulled together, multiple continuous fibers may be bound together using a thread (bundling thread), continuous fibers may be bound together and bundled together using other agents such as adhesives, pressure sensitive adhesives, and thermal fusion agents, or may be bundled by other methods.

The number of continuous fibers constituting one fiber bundle 17 is not limited, and can be, for example, 3,000 or more. By having 3,000 or more continuous fibers constituting the fiber bundle 17, the fiber aggregate 14 and the core material 13 can exhibit excellent strength while being flexible. The number is not limited, but can be, for example, 3,000 or more and 100,000 or less, 5,000 or more and 70,000 or less, 7,000 or more and 50,000 or less, and 10,000 or more and 30,000 or less.

In addition, when considering workability when handling the fiber bundles 17, it is possible to use fiber bundles (thick bundles) that have a large number of continuous fibers constituting each fiber bundle 17. In this case, the number of continuous fibers constituting each fiber bundle 17 can be, for example, 30,000 or more, further 40,000 or more, and further 60,000 or more. On the other hand, the number of continuous fibers constituting each fiber bundle 17 can be, for example, 1,500,000 or less, and further 1,000,000 or less.

(2) Middle Mold The middle mold 20 is a member for fixing the fiber aggregate 14 along the peripheral surface 201, and is a member that is removed after the matrix resin 15 has solidified (see Figures 1, 5, and 6).
Moreover, the intermediate mold 20 is a member that ultimately gives a three-dimensional shape to the fiber aggregate 14. Usually, the fiber aggregate 14 has a planar shape, and is given a three-dimensional shape by being fixed along the peripheral surface 201 of the intermediate mold 20. Furthermore, the intermediate mold 20 may be a mold independent of the outer mold 21 (e.g., upper mold, lower mold, main mold, etc.) like a core, or may be a mold protruding from the outer mold 21 as a part of the outer mold 21.

In the present invention, the intermediate mold 20 has a complex three-dimensional shape, which allows the effects of the present invention to be more pronounced. The intermediate mold 20 may be formed in any manner, and various three-dimensional modeling methods can be used, for example, 3D printing is one of the methods. The model obtained by 3D printing may be used as the intermediate mold 20 as is, or the model obtained may be reworked and then molded again to form a female mold, and then the material to become the intermediate mold 20 may be poured into the female mold to obtain the intermediate mold 20 as a male mold.
The configuration of the intermediate mold 20 will be described in detail in the explanation of the removal process R2.

Any method may be used to fix the fiber aggregate 14 to the middle mold 20, but for example, the middle mold 20 may have a recess 203 (see FIG. 1a) on the peripheral surface 201 that accommodates part or all of the thickness of the fiber aggregate 14. By having the recess 203, the fiber aggregate 14 can be fitted into this recess 203 and fixed. In addition, the recess 203 can function to suppress movement of the fiber aggregate 14 due to the impregnation pressure of the resin when the fiber aggregate 14 is impregnated with uncured resin or the like.

The middle mold 20 can have a protrusion 205 (see FIG. 1a) on the peripheral surface 201 that engages with a through hole 143 (see FIG. 1b) provided in the fiber aggregate 14. By having the protrusion 205, the through hole 143 provided in the fiber aggregate 14 can be fitted into the protrusion 205 and fixed. Furthermore, when the fiber aggregate 14 is impregnated with unsolidified resin (uncured resin, molten resin, etc.), the protrusion 205 can suppress the fiber aggregate 14 from moving due to the impregnation pressure of the resin.

Furthermore, the fiber aggregate 14 can be fixed to the peripheral surface 201 of the intermediate mold 20 by driving a fastener 207 (see FIG. 5b) from the outer surface side of the fiber aggregate 14 aligned along the peripheral surface 201 of the intermediate mold 20 toward the intermediate mold 20. Specifically, various fasteners 207 such as (1) fasteners shaped like a U-shape, L-shape, etc., and (2) fasteners having a wide fastening portion such as a thumb tack, nail, or screw, etc., can be driven into the intermediate mold 20 to fix the fiber aggregate 14 to the peripheral surface 201. As the above (1), for example, a device called a stapler, stapler, paper binder, etc. can be used. These fasteners 207 can also exert a function of suppressing the movement of the fiber aggregate 14 due to the impregnation pressure of the resin when the fiber aggregate 14 is impregnated with unsolidified resin.

In the fixing step R1, the fiber aggregate 14 is fixed along the peripheral surface 201 of the middle mold 20. By fixing the fiber aggregate 14 along the peripheral surface 201, the fiber aggregate 14 and the peripheral surface 201 are in close contact with each other, and when the fiber aggregate 14 is impregnated with the unsolidified resin, the fiber aggregate 14 can be prevented from moving due to the impregnation pressure of the resin.
Furthermore, when the fiber aggregate 14 has a belt-shaped portion 141, in the fixing step R1, it is preferable to wind the belt-shaped portion 141 around the peripheral surface 201 of the middle mold 20. By winding using the belt-shaped portion 141, it is possible to design the shape with a high degree of freedom. That is, when a planar fiber aggregate 14 is wound around the middle mold 20, the fiber aggregate 14 can only be three-dimensionally formed into a cylindrical shape. In contrast, when a belt-shaped fiber aggregate 14 is wound around the middle mold 20, in addition to a cylindrical shape, a spiral shape, a branched shape, etc. can be formed, so that a skeletal structure can be easily formed. For example, when the middle mold 20 is a cube, the middle mold 20 has a six-sided square as its peripheral surface 201. When a planar fiber aggregate 14 is used, the fiber aggregate 14 cannot be wound so as to pass through all of these six faces, but when a belt-shaped fiber aggregate 14 is used, a skeletal shape that passes through all of the six faces can be formed in a manner similar to hanging a ribbon.

[2] Removal process In the removal process R2, after the fixed fiber aggregate 14 is embedded in the matrix resin 15, the middle mold 20 is dismantled, deformed or reduced in volume to remove the fiber-reinforced molding 1 (see Figures 1d, 1e, 1f and 1g).
(1) Matrix resin 15
The matrix resin 15 is a resin in which the core material 13 is embedded. More specifically, it is a resin that is impregnated and fixed (cured in the case of a curable resin, or solidified in the case of a thermoplastic resin) so as to permeate the inside of the core material 13. As a method for impregnating and fixing this matrix resin 15, various conventionally known methods can be used.

The type of matrix resin 15 is not limited, and various resins can be used. That is, a curable resin, a thermoplastic resin, or a combination of these may be used. Examples of curable resins include epoxy resin, polyester resin (curable polyester resin), and urethane resin. On the other hand, examples of thermoplastic resins include polyolefin resin, acrylic resin, polyester resin (thermoplastic polyester resin), and polyamide resin.

Embedding in matrix resin 15 can be achieved, for example, by following the fixing step R1, an outer mold arrangement step in which the outer mold 21 covers the peripheral surface 201 of the middle mold 20 to which the fiber aggregate 14 is fixed, a filling and impregnation step in which unsolidified resin is filled in the gap between the outer mold 21 and the middle mold 20 and the fiber aggregate 14 is impregnated with the resin, and a solidification step in which the resin impregnated into the fiber aggregate 14 is solidified to obtain matrix resin 15.
Of the above, the outer mold 21 used in the outer mold arrangement process may be of any type, and in addition to using a metal mold or a resin mold, a bag-shaped object (such as a resin bag) can also be used as the outer mold 21.

(2) Removal of the Fiber-Reinforced Molded Body The fiber-reinforced molded body 1 is removed by dismantling, deforming or reducing the volume of the middle mold 20. That is, the middle mold 20 is formed from a material that can be dismantled, deformed or reduced in volume.
Among the above, dismantlable materials (items) include a bound material in which granular materials (including powder) are bound with a binder, and a coagulated material in which granular materials (including powder) are aggregated. Specifically, the former includes sand molds and compressed wood. The latter includes gypsum. As described above, the recesses 203, the protrusions 205, and the like can be formed in these intermediate molds 20 by methods such as carving and/or cutting. In addition, it is also possible to drive in the locking devices 207. In addition, the dismantling of these intermediate molds 20 can be performed by methods such as pressurization, impact application, cutting, and grinding. These dismantling methods may be used alone or in combination of two or more.

Among the above, examples of the heat-meltable material (item), heat-deformable material (item), and heat-reducable material (item) include thermoplastic compositions.Furthermore, examples of the heat-meltable material (item), heat-reducible material (item), and heat-reducible material (item), include bound materials in which granular materials are bound by a thermoplastic composition, bound materials in which powder is bound by a thermoplastic composition, and the like.
Examples of the thermoplastic composition include liquids that become solid in a temperature range below the melting point, such as thermoplastic resins, waxes, waxes, and low-melting-point metals (tin, tin alloys, etc.). When a thermoplastic composition is used as the material of the middle mold 20 and a thermosetting resin is used as the matrix resin 15, it is preferable to use a combination in which the melting point (T _B ) of the thermoplastic composition is 25° C. or higher than the curing start temperature (T _A ) of the thermosetting resin. This temperature is more preferably T _B -T _A (° C.) ≧ 30, even more preferably T _B -T _A (° C.) ≧ 40, and particularly preferably T _B -T _A (° C.) ≧ 50.

Moreover, the melting point (T _B ) is preferably 50° C. or higher. In this case, the recesses 203, the protrusions 205, etc. can be easily formed in the middle mold 20 by engraving and/or cutting or the like (mold forming can also be performed). This is also suitable from the viewpoint of driving in the locking members 207. This melting point (T _B ) is more preferably 60° C. or higher, and even more preferably 70° C. or higher. However, the melting point (T _B ) is usually 200° C. or lower.
In the removal step, if the inner mold 20 made of the thermoplastic composition can be disassembled in the same manner as above, it may be disassembled, but it is more preferable to reduce the volume and deform the inner mold 20 by heating. That is, if it is possible to remove it from the fiber-reinforced molding 1 by softening it by heating and then deforming it by applying pressure, or to remove it from the fiber-reinforced molding 1 by melting it by heating, or to dissolve it by heating, or to disappear by heating, it may be burned to reduce the volume.

When using a thermoplastic resin as the material for the middle mold 20, for example, polyolefin can be used. Polyolefin has the advantage of being easy to use as a low melting point material. Polyamide can also be used. Polyamide has the advantage of being easy to use because of its low melt viscosity.

[3] Other Steps The present method may include other steps in addition to the steps described above. That is, as described above, an outer mold disposing step may be included after the fixing step R1 and before the removal step R2. Also, a fiber aggregate forming step for obtaining a fiber aggregate 14 may be included before the fixing step R1. Furthermore, for example, the removal step R2 may include a filling step for filling the gap between the inner mold 20 and the outer mold 21 with unsolidified resin, a solidification step for solidifying the unsolidified resin to obtain a matrix resin 15, and the like. Only one of these steps may be included, or two or more of them may be included.

[4] Fiber-reinforced molding The fiber-reinforced molding 1 obtained by this method has a core material 13 and a matrix resin 15 in which the core material 13 is embedded (see Figs. 6 to 9). In the fiber-reinforced molding 1, the matrix resin 15 is a resin in which the core material 13 is embedded. More specifically, it is a resin that is impregnated and fixed (cured in the case of a curable resin, solidified in the case of a thermoplastic resin) so as to permeate the inside of the core material 13. The impregnation method and fixation method of this matrix resin 15 can be various conventionally known methods.

The type of matrix resin 15 is not limited, and various resins can be used. That is, a curable resin, a thermoplastic resin, or a combination of these may be used. Examples of curable resins include epoxy resin, polyester resin (curable polyester resin), and urethane resin. On the other hand, examples of thermoplastic resins include polyolefin resin, acrylic resin, polyester resin (thermoplastic polyester resin), and polyamide resin.

The shape, size, thickness, and other dimensions of the fiber-reinforced molding 1 produced by this method are not particularly limited. For example, this method is suitable for producing a fiber-reinforced molding 1 having a plurality of reinforcing holes H for forming a reinforcing structure, including two adjacent reinforcing holes _H1 and _H2 , and having a shape in which the opening surface of reinforcing hole _H1 and the opening surface of reinforcing hole _H2 belong to different planes (see FIGS. 6 to 8 ).

Specifically, for example, it is difficult to homogeneously form the structural parts constituting the reinforcing holes H ₁ and H ₂ using an openable and closable upper and lower molds. In this respect, in the present method, since the middle mold 20 is used, a shaping shape can be obtained separately from the upper and lower molds. Therefore, particularly excellent shaping properties can be obtained in the above-mentioned shape. For this reason, when manufacturing the fiber-reinforced molding 1 having the above-mentioned complex three-dimensional shape, it is possible to prevent the respective parts from being divided and manufactured. As a result, the fiber-reinforced molding 1 can be manufactured integrally, so that the fiber-reinforced molding 1 can be efficiently manufactured by suppressing the generation of connection points. In addition, since the generation of connection points can be suppressed, a fiber-reinforced molding in which the complexity of the shape required for connection and the increase in weight are suppressed can be obtained. Then, a fiber-reinforced molding 1 that realizes a smoother shape and has a uniform strength balance can be obtained. Furthermore, an opening reinforcement structure that could be realized by obtaining a molded body without holes and then forming holes in the necessary places in the conventional method can be obtained with a low man-hours without performing a hole-forming process.

Reinforcing holes are holes that form reinforcing structures such as truss structures, rigid frame structures, and arch structures within a three-dimensional object. In other words, by subsequently providing holes in a three-dimensional object that is generally thin, a reinforcing structure can be formed within the three-dimensional object. A three-dimensional object without holes is subject to complex loads of forces, but by providing reinforcing holes, the locations where the forces are applied can be made clear, resulting in a higher structural strength.
Conventionally, such reinforcing holes required a post-hole drilling step as described above, but with this method, reinforcing holes can be pre-drilled without cutting the fiber aggregate 14 and without reducing the reinforcing properties of the fiber aggregate 14. In other words, a better reinforcing hole can be obtained without the need for a hole drilling step. In particular, two or more reinforcing holes whose opening faces belong to different planes can be obtained at the same time.

Similarly, the present method is also excellent in the manufacture of a fiber-reinforced molding 1 having an endless, three-dimensionally connected band-shaped portion, a fiber-reinforced molding 1 having at least one of a ring-shaped portion, an annular portion, and an opening, a fiber-reinforced molding 1 having a band-shaped portion having a curved twisted surface, a fiber-reinforced molding 1 having a band-shaped branch portion three-dimensionally branched in different directions (see FIG. 5), and the like. In particular, the present method is excellent in the manufacture of a fiber-reinforced molding 1 having a band-shaped branch portion having a first branch portion 141a and a second branch portion 141b, in which each branch portion is fixed to a different peripheral surface 201 (first surface 201a and second surface 201b) of the middle mold 20.

The applications of the fiber-reinforced molding 1 obtained by this method are not particularly limited, and it can be used, for example, as exterior materials, interior materials, structural materials (body shells, car bodies, aircraft fuselages), shock absorbing materials, etc. for automobiles, railroad cars, ships, airplanes, etc. Among these, examples of automotive products include exterior materials for automobiles, interior materials for automobiles, structural materials for automobiles, shock absorbing materials for automobiles, engine room parts, etc.
Specific examples include bumpers, spoilers, cowlings, front grilles, garnishes, bonnets, trunk lids, cowl louvers, fender panels, rocker moldings, door panels, roof panels, instrument panels, center clusters, door trims, quarter trims, roof linings, pillar garnishes, deck trims, tonneau boards, package trays, dashboards, console boxes, kicking plates, switch bases, seat backboards, seat frames, armrests, sun visors, intake manifolds, engine head covers, engine under covers, oil filter housings, housings for in-vehicle electronic components (ECUs, TV monitors, etc.), energy absorbers such as air filter boxes and rush boxes, and body shell components such as front end modules.

Further examples include interior materials, exterior materials, and structural materials for buildings and furniture. That is, they can be door covering materials, door structural materials, covering materials and structural materials for various furniture (desks, chairs, shelves, chests, etc.), and even unit baths and septic tanks. They can also be used as packaging materials, containers (trays, etc.), protective materials, partition materials, etc. They can also be molded into housings and structures for home appliances (flat-screen TVs, refrigerators, washing machines, vacuum cleaners, mobile phones, portable game consoles, notebook computers, etc.).

The present invention will now be described in detail with reference to examples.
(1) Materials Used Base layer 18: vegetable fiber cloth (woven cloth made from spun cotton fibers)
Fiber bundle 17: A fiber bundle of 12,000 carbon fibers (12K multifilament)
Sewing thread 175: Resin fiber (multifilament using polyester monofilament)

(2) Preparation of fiber aggregate 14 Fiber bundles 17 were sewn to only necessary portions of base layer 18 at 1.7 mm pitch using sewing thread 175, and unnecessary portions of base layer 18 were cut away to obtain fiber aggregate 14 having a band-like shape (having a meandering shape) overall.

(3) Preparation of Fiber-Reinforced Molded Body 1 The fiber aggregate 14 obtained in the above (2) was fixed by wrapping it around a wax-made (melting point 101° C.) inner mold 20 (see FIG. 6 ) to give it a three-dimensional shape.
Thereafter, the middle mold 20 with the fiber assembly 14 fixed thereto was placed in a resin bag, and while the resin bag was being degassed, uncured epoxy resin (product number "XNR6830" manufactured by Nagase ChemteX Corporation) that would become the matrix resin was added. Next, the middle mold 20 was heated to thermally expand the wax while impregnating the fiber assembly 14 with the uncured epoxy resin, and the uncured epoxy resin was then cured to obtain a fiber-reinforced molding 1 (see FIGS. 6 to 8 ).

The obtained fiber-reinforced molded body 1 had a complex skeletal shape, but was manufactured as a single unit without the need to manufacture each part separately. This allowed the fiber-reinforced molded body 1 to be manufactured efficiently by suppressing the generation of connection points. Furthermore, because the generation of connection points could be suppressed, a fiber-reinforced molded body 1 was obtained in which the complexity of the shape required for connection and the increase in weight were suppressed. As a result, a fiber-reinforced molded body 1 with a smoother shape and uniform strength balance was obtained. Furthermore, an opening reinforcement structure that could be achieved by first obtaining a molded body without holes and then drilling holes in the necessary places in the past could be achieved by this method, but it was possible to obtain it with low labor costs without the need for a hole drilling process.

The foregoing examples are merely illustrative and are not to be construed as limiting the invention. While the invention has been described with reference to exemplary embodiments, it is understood that the words used in describing and illustrating the invention are descriptive and exemplary rather than limiting. As detailed herein, changes may be made within the scope of the appended claims without departing from the scope or spirit of the invention in its form. While the description of the invention has been made with reference to specific structures, materials and examples, it is not intended that the invention be limited to the disclosures set forth herein, but rather that the invention extends to all functionally equivalent structures, methods and uses within the scope of the appended claims.

1: Fiber-reinforced molding,
12; reinforcing fiber; 13; core material; 14; fiber aggregate;
141; strip portion, 141a; first branch portion, 141b; second branch portion, 143; through hole,
15: matrix resin,
17; fiber bundle, 171; continuous fiber, 172; fiber other than reinforcing fiber,
175: sewing thread,
18: Substratum,
20; medium size,
201; peripheral surface, 201a; first surface, 201b; second surface,
203; recessed portion, 205; protruding portion, 207; fastener,
21; outer mold, 215; degassing, 216; filling with unsolidified resin,
H, H ₁ , H ₂ ; Reinforcement hole,
R1: Fixation step;
R2: Removal step.

Claims (8)

A method for producing a fiber-reinforced molding having a core material containing reinforcing fibers and a matrix resin in which the core material is embedded,
a fixing step of fixing the fiber aggregate that becomes the core material along a peripheral surface of a medium mold;
and a removal step of dismantling, deforming or reducing the volume of the central mold after embedding the fixed fiber aggregate in the matrix resin, and removing the fiber-reinforced molding .
A method for producing a fiber-reinforced molding , wherein the middle mold has a recess on its peripheral surface that accommodates a part or all of the thickness of the fiber aggregate . The fiber-reinforced molding has two adjacent reinforcing holes H ₁ and reinforcement hole H ₂ having a plurality of reinforcing holes for forming a reinforcing structure,
The reinforcing hole H ₁ and the reinforcing hole H ₂ The method for producing a fiber-reinforced molding according to claim 1 , wherein the opening faces of and belong to different planes. The fiber aggregate has a fiber bundle formed by bundling continuous fibers including the reinforcing fibers, and a base layer to which the fiber bundle is sewn,
The method for producing a fiber-reinforced molding according to claim 1 or 2 , wherein the fiber bundles have strip-shaped portions sewn onto the base layer so as to be aligned in double rows. The method for producing a fiber-reinforced molding according to claim 3 , wherein the fixing step includes a step of winding the belt-shaped portion around the peripheral surface of the middle mold. The method for manufacturing a fiber-reinforced molding according to any one of claims 1 to 4, wherein the middle mold has a protrusion on its peripheral surface that engages with a through hole provided in the fiber aggregate. The method for manufacturing a fiber-reinforced molding according to any one of claims 1 to 5, wherein the fixing step is performed by driving a fastener from the outer surface side of the fiber aggregate aligned along the peripheral surface of the middle mold toward the middle mold. The intermediate part is made of a dismantlable material;
7. The method for producing a fiber-reinforced molding according to claim 1, wherein the material is selected from the group consisting of a bound material obtained by binding granules with a binder, and a coagulated material obtained by agglomerating granules. The intermediate mold is made of a material that can be melted by heating,
The method for producing a fiber-reinforced molding according to any one of claims 1 to 6, wherein the material is a thermoplastic composition.

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