JP2021041557A - Carbon fiber reinforced thermoplastic resin composite material and manufacturing method therefor - Google Patents

Abstract

To provide a fiber reinforced resin composite material to which excellent mechanical properties are imparted by having a rib part sufficiently filled with carbon fibers.SOLUTION: A manufacturing method of carbon fiber reinforced thermoplastic resin composite material is a method for manufacturing a carbon fiber reinforced thermoplastic resin composite material having a base part 12 and a rib part 14 provided on the base part, and the rib part contains carbon fibers 34. The manufacturing method includes the steps of: cutting a prepreg 20 in which carbon fibers are oriented in a uniaxial direction such that an average fiber length of carbon fibers is 1 cm or more and 20 cm or less; stacking a plurality of prepreg; and heat-press molding a laminate 25 containing the plurality of cut prepreg.SELECTED DRAWING: Figure 1

Description

The present invention relates to a carbon fiber reinforced thermoplastic resin composite material and a method for producing the same.

As a method for producing a carbon fiber reinforced thermoplastic resin composite material (hereinafter, also referred to as a fiber reinforced resin composite material) which is a fiber reinforced resin molded product, for example, a reinforced fiber bundle in which a plurality of continuous reinforced fibers are aligned in one direction is used. A method of shaping a laminate composed of two or more layers of uniaxial prepreg impregnated with a thermoplastic resin into a predetermined shape by heat press molding using a mold, a so-called stamping molding method, is known.

Since the fiber-reinforced resin composite material obtained by this method contains continuously reinforcing fibers, it has high mechanical strength. Further, since the continuous reinforcing fibers are regularly arranged, it is possible to design a fiber reinforced resin composite material having a desired mechanical strength, and the variation in mechanical strength is small.

However, it is difficult to shape the laminate containing the continuous reinforcing fibers into a complicated shape because the fluidity at the time of press molding is poor. Therefore, the fiber-reinforced resin composite material obtained by the stamping molding method is mainly limited to those having a nearly planar shape.

As another method for producing a fiber-reinforced resin composite material having a high rib portion, for example, the following methods (1) to (4) have been proposed.
(1) After the first resin material containing the resin and the reinforcing fibers is press-molded to obtain a primary molded product, the second resin material is formed in the space remaining between the primary molded product and the cavity surface of the mold. A method called overmolding (for example, Patent Document 1).
(2) A prepreg obtained by cutting a continuous reinforcing fiber into a discontinuous reinforcing fiber by forming a notch in a uniaxial prepreg impregnated with a thermoplastic resin in a reinforcing fiber bundle in which a plurality of continuous reinforcing fibers are aligned in one direction is used. Method (eg, Patent Document 2).
(3) A fiber-reinforced resin composite material having a rib structure manufactured by press injection hybrid molding, which has a rib root portion containing carbon fibers and a rib portion made of a thermoplastic resin, and has an average height of the rib root portion. A method of setting the ratio of Ha to the maximum thickness Tr of the rib portion within a specific range (for example, Patent Document 3).
(4) A method for manufacturing a collision energy absorbing member having a rib portion by heat-press molding a long fiber random mat (for example, Patent Document 4).

Japanese Patent No. 5072133 Japanese Unexamined Patent Publication No. 63-247012 Japanese Unexamined Patent Publication No. 2017-08930 International Publication No. 2013-08974

In the method (1), after the first press molding, a space corresponding to a complicated shape such as a rib remains between the primary molded product and the cavity surface of the mold. Next, by filling the space with the second resin material, the second resin material can be shaped into a complicated shape such as a rib. However, in the method (1), the bonding strength at the interface between the primary molded product and the second resin material is low, and the mechanical strength at the rib portion of the fiber reinforced resin molded product is insufficient.

The method (2) only discloses a laminate made of a prepreg with a notch, and does not describe a fiber-reinforced resin molded product including a rib portion.

In the method (3), the base portion and the rib root portion contain carbon fibers and have excellent strength, but the rib tip portion formed by injection does not contain carbon fibers and the ribs. Sufficient strength cannot be obtained by itself. In particular, the strength of the rib root is important for stress from the lateral direction, but the mechanical strength of the entire rib is important for stress from the vertical (rib height) direction.

In the method (4), carbon fibers randomly arranged in the base portion and the rib portion are included, but the rib structure made of a random mat material sufficiently improves the mechanical strength in a specific direction per carbon fiber content. It's difficult.

On the other hand, as a result of diligent studies, the present inventors cut the carbon fibers of the uniaxial prepreg to a specific average fiber length, and heat the laminated body in which the prepregs are laminated in multiple layers without randomizing the cut prepregs. It has been found that a fiber-reinforced resin composite material having rib portions sufficiently filled with carbon fibers can be obtained by press molding. That is, an object of the present invention is to provide a fiber reinforced resin composite material having excellent mechanical properties by having a rib portion sufficiently filled with carbon fibers.

[1] The method for producing a carbon fiber reinforced thermoplastic resin composite material according to the present invention is as follows.
A step of cutting a prepreg in which carbon fibers are oriented in the uniaxial direction so that the average fiber length of the carbon fibers is 1 cm or more and 20 cm or less.
The process of laminating multiple prepregs to form a laminate,
A laminate containing a plurality of cut prepregs is heat-press molded, and the base portion and the carbon fiber reinforced thermoplastic that is integrally molded with the base portion and protrudes from the base portion and contains the carbon fibers. Includes a step of making a resin composite.

[2] The method for producing a carbon fiber reinforced thermoplastic resin composite material according to [1], wherein a plurality of cut prepregs are laminated in the laminating step.

[3] The method for producing a carbon fiber reinforced thermoplastic resin composite material according to [1], wherein in the cutting step, a laminated body containing a plurality of laminated prepregs is cut.

[4] All the cutting lines contained in one of the two cut prepregs adjacent to the laminated body in the stacking direction are included in the other of the two cut prepregs in the projection in the stacking direction. The method for producing a carbon fiber reinforced thermoplastic resin composite material according to any one of [1] to [3], which is at least partially deviated from the cutting line of.

[5] The carbon fiber reinforcing heat according to any one of [1] to [4], wherein the orientation direction of the carbon fibers of the plurality of prepregs contained in the laminate is 1 or more and 4 or less. A method for manufacturing a plastic resin composite material.

[6] The ratio (H / T) of the protrusion height H [mm] of the rib portion from the base portion to the thickness T [mm] of the rib portion is 10 or more and 500 or less, [1] to [ 6] The method for producing a carbon fiber reinforced thermoplastic resin composite material according to any one of.

[7] The rib portion has a longitudinal direction along the base portion and has a longitudinal direction.
The carbon fiber reinforced thermoplastic according to any one of [1] to [6], wherein the orientation direction of the carbon fibers of at least one prepreg contained in the laminate is parallel or orthogonal to the longitudinal direction of the rib portion. A method for manufacturing a resin composite material.

[8] The method for producing a carbon fiber reinforced thermoplastic resin composite material according to any one of [1] to [7], wherein the base portion and the rib portion are integrally molded.

[9] In the cutting step, the prepreg is cut along a cutting line along a direction non-parallel to the uniaxial direction, and at least one end of the cutting line is located inside the peripheral edge of the prepreg. The method for producing a carbon fiber reinforced thermoplastic resin composite material according to any one of [1] to [8].

[10] The method for producing a carbon fiber-reinforced thermoplastic resin composite material according to any one of [1] to [8], wherein the prepreg is cut so as to be divided into a plurality of prepreg pieces in the cutting step.

[11] In the cutting step, one prepreg and another prepreg are cut at the same constant pitch along the uniaxial direction.
In the laminating step, the one prepreg and the other prepreg are aligned with each other in the orientation direction of the carbon fibers and the cutting position is deviated in the orientation direction, preferably half of the constant pitch. The method for producing a carbon fiber reinforced thermoplastic resin composite material according to any one of [1] to [10], wherein the carbon fiber reinforced thermoplastic resin composite material is laminated so that the cutting position is deviated in the orientation direction by the length.

[12] The rib portion has a longitudinal direction along the base portion and has a longitudinal direction.
The carbon fiber reinforced thermoplastic resin composite material according to any one of [1] to [11], wherein the cutting line of at least one prepreg contained in the laminate is inclined with respect to the longitudinal direction of the rib portion. Production method.

[13] The carbon fiber reinforced thermoplastic resin composite material has a plurality of plate-shaped rib portions.
One rib portion contained in the carbon fiber reinforced thermoplastic resin composite material has a longitudinal direction along the base portion and has a longitudinal direction.
The other rib portion contained in the carbon fiber reinforced thermoplastic resin composite material has a longitudinal direction along the base portion that is non-parallel to the longitudinal direction of the one rib portion.
The orientation direction of the carbon fibers of one prepreg contained in the laminate is parallel to the longitudinal direction of the one rib portion.
The carbon according to any one of [1] to [12], wherein the orientation direction of the carbon fibers of the other prepreg contained in the laminate is parallel to the longitudinal direction of the other rib portion. A method for producing a fiber-reinforced thermoplastic resin composite material.

[14] The carbon fiber reinforced thermoplastic resin composite material has a plurality of plate-shaped rib portions that are arranged apart from each other in the arrangement direction and each extends in a longitudinal direction non-parallel to the arrangement direction.
In the step of producing the cut prepreg, the prepreg is cut so that the average fiber length of the carbon fibers is equal to or less than the distance between the two adjacent rib portions along the arrangement direction, [1] to [13]. ] The method for producing a carbon fiber reinforced thermoplastic resin composite material according to any one of.

[15] The carbon fiber reinforced thermoplastic resin composite material is arranged apart from each other in the first arrangement direction, and a plurality of plate-shaped first ribs each extending in a first longitudinal direction non-parallel to the first arrangement direction. A plurality of plate-shaped second rib portions that are arranged apart from each other in the second arrangement direction that is non-parallel to the first arrangement direction and extend in the second longitudinal direction that is non-parallel to the second arrangement direction. Have,
The orientation direction of the carbon fibers of one prepreg contained in the laminate is parallel to the first longitudinal direction, and the average fiber lengths of the carbon fibers of the one prepreg are adjacent to each other along the second arrangement direction. It is less than or equal to the distance between the two matching second ribs.
The orientation direction of the carbon fibers of the other prepreg contained in the laminate is parallel to the second longitudinal direction, and the average fiber length of the carbon fibers of the other prepreg is the first arrangement direction. The method for producing a carbon fiber reinforced thermoplastic resin composite material according to any one of [1] to [14], which is equal to or less than the distance between two first rib portions adjacent to each other along the above.

[16] A carbon fiber reinforced thermoplastic resin composite material produced by the production method according to any one of [1] to [15].

[17] A carbon fiber reinforced thermoplastic resin composite material having a plurality of carbon fibers and a thermoplastic resin.
With the base part
A rib portion protruding from the base portion is provided.
A carbon fiber reinforced thermoplastic resin composite material in which at least a part of carbon fibers extends across the base portion and the rib portion.

[18] A carbon fiber reinforced thermoplastic resin composite material having a plurality of carbon fibers and a thermoplastic resin.
With the base part
A rib portion protruding from the base portion is provided.
The rib portion has a longitudinal direction along the base portion and has a longitudinal direction.
A carbon fiber reinforced thermoplastic resin composite material in which at least a part of carbon fibers is located in the rib portion and extends in the longitudinal direction over the entire length thereof.

[19] A plurality of rib portions arranged apart from each other in the uniaxial direction are arranged.
The carbon fiber reinforced thermoplastic resin composite material according to [17] or [18], wherein the length of at least a part of the carbon fibers is shorter than the distance between the plurality of rib portions along the uniaxial direction.

[20] The carbon fiber according to any one of [17] to [19], wherein one end of at least a part of the carbon fibers is located in the base portion and the other end is located in the rib portion. Reinforced thermoplastic resin composite material.

According to the present invention, the rib portion of the fiber-reinforced resin composite material can be sufficiently filled with carbon fibers, whereby excellent mechanical properties can be imparted to the fiber-reinforced resin composite material.

FIG. 1 is a diagram for explaining an embodiment of the present invention, and is a perspective view showing an example of a carbon fiber reinforced thermoplastic resin composite material. FIG. 2 is a top view showing the carbon fiber reinforced thermoplastic resin composite material of FIG. FIG. 3 is a vertical cross-sectional view showing the carbon fiber reinforced thermoplastic resin composite material of FIG. 1, and shows a cross section taken along the line III-III of FIG. FIG. 4 is a view corresponding to FIG. 1 and is a perspective view showing another example of the carbon fiber reinforced thermoplastic resin composite material. FIG. 5 is a view corresponding to FIG. 1 and is a perspective view showing still another example of the carbon fiber reinforced thermoplastic resin composite material. FIG. 6 is a diagram for explaining an example of a method for producing a carbon fiber reinforced thermoplastic resin composite material. FIG. 7 is a diagram for explaining an example of a method for producing a carbon fiber reinforced thermoplastic resin composite material. FIG. 8 is a diagram for explaining an example of a method for producing a carbon fiber reinforced thermoplastic resin composite material. FIG. 9 is a diagram for explaining an example of a cutting method in a method for producing a carbon fiber reinforced thermoplastic resin composite material. FIG. 10 is a diagram for explaining another example of a cutting method in a method for producing a carbon fiber reinforced thermoplastic resin composite material. FIG. 11 is a diagram for explaining still another example of the cutting method in the method for producing the carbon fiber reinforced thermoplastic resin composite material. FIG. 12 is a diagram for explaining still another example of the cutting method in the method for producing the carbon fiber reinforced thermoplastic resin composite material. FIG. 13 is a diagram for explaining an example of a laminating method in a method for producing a carbon fiber reinforced thermoplastic resin composite material. FIG. 14 is a diagram for explaining another example of the laminating method in the method for producing a carbon fiber reinforced thermoplastic resin composite material. FIG. 15 is a diagram for explaining still another example of the laminating method in the method for producing the carbon fiber reinforced thermoplastic resin composite material. FIG. 16 is a diagram for explaining another example of a method for producing a carbon fiber reinforced thermoplastic resin composite material. FIG. 17 is a diagram for explaining an example of a heat press molding method of a method for producing a carbon fiber reinforced thermoplastic resin composite material. FIG. 18 is a diagram for explaining an example of a heat press molding method of a method for producing a carbon fiber reinforced thermoplastic resin composite material.

Hereinafter, an embodiment of the present invention will be described with reference to the drawings. In the drawings attached to the present specification, the scale, aspect ratio, etc. are appropriately changed from those of the actual product and exaggerated for the convenience of illustration and comprehension.

1 to 18 are diagrams for explaining one embodiment of the present invention. Of these, FIGS. 1 to 3 are a perspective view, a top view, and a cross-sectional view showing a specific example of the carbon fiber reinforced thermoplastic resin composite material, respectively. 4 and 5 are perspective views showing another example of the carbon fiber reinforced thermoplastic resin composite material, respectively. 6 to 8 are views for explaining an example of a method for producing a carbon fiber reinforced thermoplastic resin composite material. 9 to 18 are views for explaining details of a method for producing a carbon fiber reinforced thermoplastic resin composite material and examples of modifications.

In one embodiment described below, a device is made to sufficiently fill the rib portion of the fiber reinforced resin composite material with carbon fibers. As a result, the resulting carbon fiber reinforced thermoplastic resin composite has sufficient mechanical properties due to the carbon fibers, typically excellent tensile strength and excellent flexural rigidity.

Hereinafter, one embodiment will be described with reference to the specific examples shown in the drawings. In order to clarify the directional relationship between the drawings, some drawings show the orientation direction OD, the arrangement direction AD, the longitudinal direction LD, and the like as common directions between the drawings.

First, the carbon fiber reinforced thermoplastic resin composite material 10 will be described. In the following description, "carbon fiber reinforced thermoplastic resin composite material" is abbreviated as "fiber reinforced resin composite material".

As shown in FIGS. 1 to 5, the fiber reinforced resin composite material 10 has a base portion 12 and a rib portion 14 protruding from the base portion 12. The base portion 12 and the rib portion 14 include a thermoplastic resin 32 as a base material and carbon fibers 34 held by the thermoplastic resin 32. The rib portion 14 is integrally molded with the base portion 12 by a manufacturing method described later. Details of the materials and the like used for the thermoplastic resin 32 and the carbon fiber 34 will be described later in the method for producing the fiber reinforced resin composite material 10.

The base portion 12 typically has a flat outer shape. However, the present invention is not limited to this example, and the base portion 12 can have various outer shapes such as a rectangular parallelepiped shape, a rotating body shape, and a frustum shape.

The fiber-reinforced resin composite material 10 having the illustrated flat plate-shaped base portion 12 has a flat shape as a whole. When the fiber-reinforced resin composite material 10 is viewed as a whole and from a broad perspective, the direction orthogonal to the plane direction of the fiber-reinforced resin composite material 10 is referred to as the normal direction ND of the fiber-reinforced resin composite material 10. The normal direction ND of the fiber reinforced resin composite material 10 coincides with the normal direction of the flat plate-shaped base portion 12 in the illustrated example.

The rib portion 14 extends from the surface of the base portion 12. The rib portion 14 reinforces the base portion 12. The rib portion 14 typically extends from the surface of the base portion 12 in the normal direction ND. The shape and quantity of the rib portion 14 are not particularly limited. The rib portion 14 may be provided only on one surface of the base portion 12 as in the illustrated example. As another example, the rib portion 14 may be provided on a plurality of surfaces of the base portion 12, or may be provided on a pair of main surfaces of the base portion 12 having a flat plate shape. Further, the rib portion 14 may be provided on the base portion 12 in various patterns.

The rib portion 14 may be formed in a rod shape or a flat plate shape so as to extend on the base portion 12. According to the rib portion 14 formed in a rod shape or a flat plate shape, it is possible to effectively improve the mechanical properties of the fiber reinforced resin composite material 10 while effectively suppressing the weight increase of the fiber reinforced resin composite material 10. it can. Further, a plurality of rib portions 14 having the longitudinal LD may intersect on the base portion 12. By intersecting the plurality of rib portions 14 on the base portion 12, mechanical properties in various directions can be effectively improved. Usually, in the fiber reinforced resin composite material 10 provided with the rib portion 14 having the longitudinal LD, the rigidity in the longitudinal LD and the bending rigidity around the axis orthogonal to the longitudinal LD can be significantly improved. Conversely, in the fiber reinforced resin composite material 10 that receives a tensile force, a rib portion 14 having a longitudinal LD along the direction in which the tensile force is applied is usually provided. Further, in the fiber reinforced resin composite material 10 that receives a bending force, a rib portion 14 having a longitudinal LD along a direction orthogonal to the bending axis of the bending force is usually provided.

In the examples shown in FIGS. 1 to 3, the rib portions 14 are provided on the base portion 12 in a grid pattern. In the fiber-reinforced resin composite material 10, the rib portion 14 has a plurality of plate-shaped first rib portions 14A and a plurality of plate-shaped second rib portions 14B. Each first rib portion 14A intersects a plurality of second rib portions 14B. Each second rib portion 14B intersects a plurality of first rib portions 14A. The plurality of rib portions 14 are integrally molded with each other.

In the example shown in FIGS. 1 to 3, the plurality of first rib portions 14A are arranged in the first arrangement direction AD1 along the base portion 12. In particular, in the illustrated example, the plurality of first rib portions 14A are arranged with a constant separation interval DA1 (see FIG. 2) in the first arrangement direction AD1. Each first rib portion 14A extends linearly in the first longitudinal direction LD1 along the base portion 12. In particular, in the illustrated example, each first rib portion 14A extends linearly along the first longitudinal direction LD1 orthogonal to the first arrangement direction AD1.

In the example shown in FIGS. 1 to 3, the plurality of second rib portions 14B are arranged in the second arrangement direction AD2 along the base portion 12. In particular, in the illustrated example, the plurality of second rib portions 14B are arranged with a constant separation interval DA2 (see FIG. 2) in the second arrangement direction AD2. Further, the second arrangement direction AD2 is orthogonal to the first arrangement direction AD1. Each second rib portion 14B extends linearly in the second longitudinal direction LD2 along the base portion 12. In particular, in the illustrated example, each second rib portion 14B extends linearly along the second longitudinal direction LD2 orthogonal to the second arrangement direction AD2. Further, the second longitudinal direction LD2 is orthogonal to the first longitudinal direction LD1.

Next, in the example shown in FIG. 4, the rib portion 14 has a plate-shaped rib portion forming a grid shape on the base portion 12 and a plate-shaped rib portion extending along a rectangular diagonal line formed by the grid. Includes ribs. In the example shown in FIG. 5, the rib portion 14 includes rib portions arranged in a honeycomb arrangement on the base portion 12. Each rib portion is formed in a plate shape and extends along one side of a regular hexagon.

As shown in FIG. 3, the rib portion 14 extends from the base portion 12 in the normal direction ND in a cross section orthogonal to the longitudinal LD. The thickness T of the rib portion 14 may be constant at each position along the ND in the normal direction. However, considering the manufacturing method by molding, it is preferable that the cross-sectional shape of the base portion 12 is tapered as it is separated from the base portion 12 in consideration of releasability. Specifically, the base portion 12 may be tapered so that both side surfaces are inclined by 1 ° or more and 2 ° or less with respect to the normal direction ND. Further, the cross-sectional shape of the rib portion 14 is not limited to a rectangular shape or a frustum shape as in the illustrated example, and may be various shapes.

In the fiber reinforced resin composite material 10, the height H of the rib portion 14 is preferably 10 mm or more and 100 mm or less. By setting the height H of the rib portion 14 in the above range, the fiber reinforced resin composite material 10 can be obtained with high productivity. The height H of the rib portion 14 is more preferably 2 mm or more and 80 mm or less, further preferably 5 mm or more and 50 mm or less, and particularly preferably 8 mm or more and 30 mm or less.

Further, from the viewpoint of ensuring moldability in heat press molding, the ratio (H) of the protrusion height H [mm] of the rib portion 14 from the base portion 12 to the thickness T [mm] orthogonal to the height of the rib portion 14. / T) is preferably 10 or more and 500 or less. This ratio (H / T) is more preferably 11 or more and 100 or less, and further preferably 12 or more and 50 or less.

In the fiber reinforced resin composite material 10, the thickness K of the base portion 12 is preferably 0.01 mm or more and 40 mm or less. By setting the thickness K of the base portion 12 in the above range as in the height H of the rib portion 14, the fiber-reinforced resin composite material 10 can be obtained with high productivity. The thickness K of the base portion 12 is more preferably 0.1 mm or more and 10 mm or less, further preferably 0.2 mm or more and 5 mm or less, and particularly preferably 0.3 mm or more and 2 mm or less.

By the way, the base portion 12 and the rib portion 14 of the fiber-reinforced resin composite material 10 have a thermoplastic resin 32 as a base material and carbon fibers 34 held by the thermoplastic resin 32. The rib portion 14 is integrally molded with the base portion 12. In particular, in the present embodiment, not only the thermoplastic resin 32 is continuously provided across the base portion 12 and the rib portion 14, but also the carbon fiber 34 is straddled over the base portion 12 and the rib portion 14. It is provided. According to such a fiber-reinforced resin composite material 10, the joint strength between the base portion 12 and the rib portion 14 can be effectively improved, and the fiber-reinforced resin composite material 10 is imparted with excellent mechanical properties. Can be done.

Further, by adjusting the average fiber length of the carbon fibers as described later, as shown in FIG. 3, at least one end of the carbon fibers 34 is located in the base portion 12, and the carbon fibers The other end of 34 will be located within the rib portion 14. According to such a fiber-reinforced resin composite material 10, the joint strength between the base portion 12 and the rib portion 14 can be effectively improved, and the fiber-reinforced resin composite material 10 is imparted with excellent mechanical properties. Can be done.

Similarly, by adjusting the average fiber length of the carbon fibers as described later, at least a part of the carbon fibers 34 is extended in the longitudinal direction LD of the rib portion 14, as shown in FIG. It will be located in the rib portion 14 over the entire length. As described above, the rib portion 14 is usually provided for the purpose of reinforcement, and receives tensile stress in the longitudinal direction thereof. Therefore, the presence of the carbon fibers 34 extending along the longitudinal LD of the rib portion 14 can effectively impart desired mechanical properties to the fiber reinforced resin composite material 10.

As shown by the alternate long and short dash line in FIG. 3, an additional layer made of metal or resin may be laminated on the fiber reinforced resin composite material 10. In the example shown by the alternate long and short dash line in FIG. 3, the resin layer 16 and the metal layer 17 are laminated in this order on the base portion 12 of the fiber reinforced resin composite material 10. However, unlike the example shown in FIG. 3, the metal layer 17 and the resin layer 16 may be laminated in this order on the base portion 12 of the fiber reinforced resin composite material 10, or the resin layer 16 and the metal may be laminated in this order. Only one of the layers 17 may be laminated on the base portion 12, or two or more layers of the resin layer 16 and the metal layer 17 may be laminated.

Next, a method for producing the fiber-reinforced resin composite material will be described.

In the method for producing a fiber-reinforced resin composite material described below, the uniaxial carbon fiber prepreg 20 in which the carbon fibers 34 are oriented in the uniaxial direction UD is cut so that the average fiber length of the carbon fibers 34 is 1 cm or more and 20 cm or less. (See FIG. 6), a step of laminating a plurality of prepregs 20 (see FIG. 7), and a step of heat-press molding a laminate 25 containing a plurality of cut prepregs 22 (see FIG. 8). Includes. According to such a manufacturing method, the fiber-reinforced resin composite material 10 in which the thermoplastic resin 32 and the carbon fiber 34 are sufficiently filled in the base portion 12 can be manufactured. Hereinafter, each step will be described.

First, a cutting step for cutting the prepreg 20 will be described.

The prepreg 20 to be cut contains the thermoplastic resin 32 and the carbon fibers 34. The prepreg 20 is a uniaxial carbon fiber prepreg, in which the carbon fibers 34 are oriented in the uniaxial UD. That is, the carbon fiber 34 extends substantially along the uniaxial UD. In the prepreg 20, a large number of carbon fibers 34 are arranged in a direction orthogonal to the uniaxial UD. As a result, a large number of carbon fibers 34 contained in the prepreg 20 are arranged in a sheet shape. The thermoplastic resin 32 impregnates the bundle of carbon fibers 34 thus arranged as a matrix resin. The prepreg 20 has a sheet-like outer shape.

The uniaxial prepreg 20 can be made as follows. First, a carbon fiber sheet-like material is produced by arranging carbon fiber bundles containing a plurality of carbon fibers (single fibers) extending in the uniaxial direction UD in a direction orthogonal to the uniaxial direction UD. The number of carbon fibers constituting one carbon fiber bundle can be 1000 or more and 100,000 or less. Basis weight of the carbon fibers in the carbon fiber sheet-like material may be a 700 g / m ² or more 7000 g / m ² or less. When the basis weight of the carbon fibers is 700 g / m ² or more, the mechanical strength of the prepreg 20 obtained by using the carbon fiber bundle can be improved. When the grain size of the carbon fibers is 7,000 g / m ² or less, the thermoplastic resin can be uniformly impregnated between the carbon fibers, and the mechanical strength of the prepreg obtained by using the carbon fiber bundle can be improved. ..

Next, the carbon fiber sheet-like material and the thermoplastic resin film are laminated. Then, the prepreg 20 is obtained by impregnating the carbon fiber sheet-like material with the thermoplastic resin by heating and pressurizing the laminate of the carbon fiber sheet-like material and the thermoplastic resin film.

As the carbon fibers 34 contained in the prepreg 20, polypropylene and polypropylene acid modified products, polyvinyl chloride, chlorinated polyvinyl chloride, ethylene vinyl chloride copolymer, vinyl acetate vinyl chloride copolymer, α-olefin vinyl chloride copolymer, maleate bi Copolymer, Polysulfone, Polyethersulfone, Polyetherketone, Polyetheretherketone, Aromatic or aliphatic polyamide, Aromatic polyester, Aromatic polycarbonate, Polyetherimide, Polyarylene oxide, Thermoplastic polyimide, Polyamideimide, Poly Examples thereof include resins selected from the group of butylene terephthalate, polyethylene terephthalate, polyethylene, acrylonitrile butadiene styrene, and polyphenylene sulfide resin, which may be used alone or in combination of two or more.

On the other hand, as the carbon fiber 34 contained in the prepreg 20, for example, a PAN-based carbon fiber, a PITCH-based carbon fiber, or the like can be used. The fiber diameter of the carbon fiber 34 is preferably 6 μm or more, more preferably 7 μm or more. The fiber diameter of the carbon fiber 34 is preferably 30 μm or less, more preferably 27 μm or less. In the present invention, the fiber diameter means the diameter of a perfect circle having the smallest diameter that can surround this cross section in a cross section along a direction orthogonal to the length direction of the fiber.

The carbon fiber volume content (Vf) of the prepreg 20 may be 10% or more and 70% or less. By setting the carbon fiber volume content (Vf) to 10% or more and 70% or less, the resin can be sufficiently impregnated, and the fiber reinforced resin composite material 10 can be obtained with high productivity. The upper limit of the carbon fiber volume content (Vf) is preferably 60% or less, more preferably 55% or less. On the other hand, the lower limit of the carbon fiber volume content (Vf) is preferably 20% or more, more preferably 30% or more.

The thickness of one prepreg 20 can be variously selected according to the fiber-reinforced resin composite material 10 to be manufactured, and depends on the height H of the rib portion 14 and the thickness K of the base portion 12, but is 0. It can be 0.03 mm or more and 0.60 mm or less. The upper limit of the thickness of the prepreg 20 is preferably 0.50 mm or less, more preferably 0.40 mm or less. On the other hand, the lower limit of the thickness of the prepreg 20 is preferably 0.04 mm or more, more preferably 0.05 mm or more.

In the step of cutting the prepreg 20, the prepreg 20 described above is cut. In this step, the length of the carbon fibers 34 is shortened while maintaining the orientation of the carbon fibers 34 in the prepreg 20 in the uniaxial direction UD. Specifically, the prepreg 20 has an average fiber length of 1 cm or more and 20 cm or less, more preferably 1.2 cm or more and 10 cm or less, and even more preferably 2 cm or more and 5 cm or less. To disconnect. By shortening the carbon fiber 34, the fluidity of the carbon fiber 34 in the heat pressing process is improved, which makes it possible to sufficiently fill the rib portion 14 with the carbon fiber 34.
The average fiber length can be measured, for example, by the following method.
(I) A test piece having a width of 5 mm, a thickness of 3 mm, and a length of 15 mm is cut out from the molded product.
(Ii) The test piece is immersed in a solvent (eg, nitric acid, trifluoroacetic acid, etc.) to dissolve components other than the carbon fiber 34, and only the carbon fiber 34 is taken out from the test piece.
(Iii) The taken-out fibrous reinforcing material is dispersed in water or the like as necessary, observed with an optical microscope (magnification of about 50 times) or the like, and the fiber length of 500 fibrous reinforcing materials in the field of view is measured. ..

In order to shorten the length of the carbon fiber 34, the prepreg 20 is cut along a cutting line CT that is non-parallel to the orientation direction OD. The orientation direction OD is the direction in which the carbon fibers 34 extend and coincides with the uniaxial direction UD in which the carbon fibers 34 extend in the prepreg 20. Typically, as shown in FIG. 6, the prepreg 20 is cut along a cutting line CT orthogonal to the orientation direction OD of the carbon fibers 34 in the prepreg 20. However, the cutting line CT may be orthogonal to the orientation direction OD at least in a part, and may be inclined with respect to the orientation direction OD in at least a part as shown in FIG.

In the example shown in FIG. 6, the prepreg 20 is cut along three cutting lines CT orthogonal to the orientation direction OD. The cut prepreg 22 formed by cutting the prepreg 20 includes four divided prepreg pieces 23. In one prepreg 20 to be cut, the plurality of cutting lines CT may be spaced at equal intervals or may be spaced at non-constant intervals. That is, the obtained plurality of prepreg pieces 23 may have the same dimensions along the orientation direction OD, or may have different dimensions along the orientation direction OD.

In the example shown in FIG. 9, the prepreg 20 is cut along three cutting lines CT that are inclined with respect to the orientation direction OD. The cut prepreg 22 formed by cutting the prepreg 20 includes four divided prepreg pieces 23. In one prepreg 20 to be cut, the angles formed by the plurality of cutting lines CT with respect to the orientation direction OD may be the same or different from each other. The obtained plurality of prepreg pieces 23 may have the same dimensions along the orientation direction OD, or may have different dimensions along the orientation direction OD.

However, not all cutting lines CT need to be non-parallel to the orientation direction OD of the carbon fibers 34 in the prepreg 20. It is sufficient that at least a part of the cutting line CT is non-parallel to the orientation direction OD of the carbon fiber 34 in the prepreg 20. Even in such a case, the average fiber length of the carbon fibers 34 can be adjusted. For example, as shown in FIG. 10, a part of the cutting line CT may be parallel to the orientation direction OD of the carbon fibers 34 in the prepreg 20 to be cut. The flow of the carbon fibers 34 in the heat press molding step can also be promoted by cutting the prepreg 20 into smaller pieces. In the example shown in FIG. 10, the prepreg 20 is cut along the cutting line CT parallel to the orientation direction OD, and is also cut along the cutting line CT orthogonal to the orientation direction OD. As a result, the cut prepreg 22 formed by cutting the prepreg 20 shown in FIG. 10 contains four prepreg pieces 23.

Further, in the examples shown in FIGS. 6, 9 and 10, the cutting line CT extends over the entire width of the prepreg 20, and the cut prepreg 22 includes a plurality of prepreg pieces 23. The divided cut prepreg 22 maintains the orientation direction OD of the carbon fibers 34 in the laminating step and the heat pressing step described later, that is, the carbon fibers 34 of each prepreg piece 23 extend in a common uniaxial direction UD. And be treated. In other words, the cut prepreg 22 including the plurality of prepreg pieces 23 is handled while keeping the orientations of the plurality of prepreg pieces 23 in a constant relationship, that is, keeping the orientation directions OD of the plurality of prepreg pieces 23 parallel to each other. ..

On the other hand, as in the examples shown in FIGS. 11 and 12, the cutting line CT may not extend over the entire width of the prepreg 20. For example, at least one end of the cutting line CT may be located inside the peripheral edge of the prepreg 20. In the examples shown in FIGS. 11 and 12, the cut prepreg 22 is not divided into a plurality of prepreg pieces 23, and is excellent in handleability. In the example shown in FIG. 11, the cutting line CT extends from one of the pair of opposing edges and does not reach the other edge. In the example shown in FIG. 12, the cutting line CT extends alternately from one and the other of the pair of opposing edges.

Further, if the length of the carbon fiber 34 can be adjusted, it is not necessary to cut the prepreg 20 by the total thickness of the prepreg 20. For example, the prepreg 20 may be cut to a depth that divides the carbon fiber 34 in the thickness direction, but the portion of the thermoplastic resin 32 may not be divided.

The cutting of the prepreg 20 described above is not particularly limited, and is carried out using various cutting devices such as scissors, a cutter, and a punching machine.

Next, the step of laminating will be described. The laminate 25, which is a raw material for heat press processing, is produced by laminating a plurality of prepregs 20. The number of prepregs 20 contained in the laminate 25 is variously selected according to the fiber reinforced resin composite material 10 to be produced. The number of prepregs 20 included in the laminated body 25 may include, for example, 2 or more and 48 or less laminated prepregs 20, and further, 6 or more and 20 or less laminated prepregs 20. May be good

In the example shown in FIG. 7, the laminating step is performed after the cutting step. As shown in FIG. 7, the laminated body 25 is manufactured by laminating a plurality of cut prepregs 22. Each prepreg 20 handled in this laminating step is a cut prepreg 22, and is divided into a plurality of prepreg pieces 23 by a cutting line CT. Each of the cut prepregs 22 has a carbon fiber 34 in a plurality of prepreg pieces 23 included in the cut prepreg 22 oriented in a certain arrangement direction AD so as to be aligned with another prepreg 20 (cut prepreg 22). Stacked.

As shown in FIG. 7, the disconnection CTs in the projection in the cutting / stacking direction DD may not coincide with each other among the plurality of cut prepregs 22 included in the laminated body 25. By shifting the position of the cutting line CT between the cut prepregs 22 contained in the laminate 25, it is possible to suppress the distribution variation of the carbon fibers 34 in the finally obtained fiber reinforced resin composite material 10.

In the example shown in FIG. 7, the laminated body 25 has four or more prepregs 20 including the illustrated first to fourth prepregs. In FIG. 7, the cutting lines CT provided on the first to fourth prepregs 20 stacked in this order are shown as the first cutting line CT1 to the fourth cutting line CT4, respectively. Similarly, in FIGS. 13 to 15 which will be referred to later, the first to fourth prepregs 20 which are laminated in order to form one laminated body 25 are shown. In FIGS. 13 to 15, the cutting lines CT provided on the first to fourth prepregs 20 are shown as the first cutting line CT1 to the fourth cutting line CT4, respectively. Further, in FIGS. 13 to 15, the arrangement direction ADs of the carbon fibers 34 in the first to fourth prepregs 20 are shown as the first arrangement direction AD1 to the fourth arrangement direction AD4, respectively.

In the examples shown in FIGS. 7 and 13, the disconnection CT in the projection in the stacking direction DD does not overlap between the two prepregs 20 (cut prepregs 22) adjacent to the stacking direction DD of the laminated body 25. There is. In particular, any cutting line CT included in one of the two prepregs 20 adjacent to the stacking direction DD of the laminated body 25 is laminated with any cutting line CT included in the other of the two prepregs 20 over the entire length. It does not overlap with DD. In other words, any cut line CT contained in one of the two prepregs 20 adjacent to the stacking direction DD of the laminate 25 is all cuts contained in the other of the two prepregs 20 in projection into the stacking direction DD. It is at least partially deviated from the line CT. According to such an example, in the finally obtained fiber-reinforced resin composite material 10, the distribution variation of the carbon fibers 34 can be suppressed more effectively. In particular, it is possible to effectively suppress the generation of regions in the fiber-reinforced resin composite material 10 in which the carbon fibers 34 are not filled and the generation of regions in the fiber-reinforced resin composite material 10 in which the density of the carbon fibers 34 is low. it can.

Further, in the example shown in FIG. 13, one prepreg 20 (cut prepreg 22) and another prepreg 20 (cut prepreg 22) contained in the laminated body 25 are arranged at a constant pitch along the orientation direction OD. It has been disconnected. More specifically, the plurality of cutting lines CT in which the prepreg 20 is cut are arranged at a constant pitch PP in the orientation direction OD. Then, one prepreg 20 and the other prepreg 20 are laminated so that the orientation directions OD of the respective carbon fibers 34 are aligned and the cutting line CT is deviated from the orientation direction OD. In particular, one prepreg 20 and another prepreg 20 are arranged adjacent to the stacking direction DD. According to such an example, it is effective to generate a region in the fiber reinforced resin composite material 10 in which the carbon fiber 34 is not filled and a region in the fiber reinforced resin composite material 10 in which the density of the carbon fiber 34 is low. Can be suppressed. At the same time, the distribution of the carbon fibers 34 in the fiber reinforced resin composite material 10 can be effectively made uniform.

In particular, in the example shown in FIG. 13, one prepreg 20 (cut prepreg 22) and another prepreg 20 (cut prepreg 22) are cut at the same constant pitch along the orientation direction OD. .. One prepreg 20 and the other prepreg 20 are laminated so that the orientation directions OD of the respective carbon fibers 34 are aligned and the cutting line CT is deviated to the orientation direction OD by half the length of the constant pitch. There is. According to such an example, the distribution of the carbon fibers 34 in the fiber reinforced resin composite material 10 can be more effectively made uniform.

Further, in the example shown in FIG. 14, the disconnection CT in the projection in the stacking direction DD does not overlap between the arbitrary prepregs 20 (cut prepregs 22) included in the laminated body 25. In particular, any cutting line CT included in any prepreg 20 included in the laminated body 25 does not overlap with any cutting line CT included in the other prepreg 20 in the stacking direction DD over the entire length. In other words, any cut line CT contained in any prepreg 20 included in the laminate 25 is at least partially deviated from any cut line CT contained in the other prepreg 20 in projection to the stacking direction DD. There is. According to such an example, in the finally obtained fiber-reinforced resin composite material 10, the distribution variation of the carbon fibers 34 can be suppressed more effectively. In particular, it is possible to effectively suppress the generation of regions in the fiber-reinforced resin composite material 10 in which the carbon fibers 34 are not filled and the generation of regions in the fiber-reinforced resin composite material 10 in which the density of the carbon fibers 34 is low. it can.

Unlike the examples shown in FIGS. 13 and 14, the orientation direction OD may be different among the plurality of prepregs 20 (cut prepregs 22) included in the laminated body 25. For example, the orientation direction OD of the carbon fibers 34 of the plurality of prepregs contained in the laminate 25 may be oriented in a direction of 1 or more and 4 or less. As an example, in the example shown in FIG. 15, the orientation directions OD of the first to fourth prepregs 20 face four different first orientation directions OD1 to fourth orientation directions OD4. By shifting the orientation direction OD of the carbon fibers 34 among the plurality of prepregs 20 (cut prepregs 22) contained in the laminate 25, the fiber-reinforced resin composite 10 finally produced is mechanically produced in the plurality of directions. The characteristics can be improved.

By the way, the laminating step may be carried out after the cutting step as shown in FIG. 7, or may be carried out before the cutting step as shown in FIG. When the laminating step is carried out after the cutting step, the arrangement of the cutting line CT can be adjusted among the plurality of prepregs 20 to be laminated.

Further, in order to improve the handleability of the laminated body 25, the plurality of prepregs 20 and the plurality of prepreg pieces 23 contained in the laminated body 25 may be fixed to each other by preheating the laminated body 25. The preheating temperature is not particularly limited as long as it is the temperature at which the thermoplastic resin contained in the laminate 25 melts, but is preferably 180 ° C. or higher and 400 ° C. or lower, and more preferably 185 ° C. or higher and 315 ° C. or lower. More preferably, it is 190 ° C. or higher and 300 ° C. or lower, and it is particularly preferable that the temperature is the same as the heating temperature in the heat press molding described below. Further, the laminate may be pressurized at the time of preheating. By pressurizing, the laminate can be heated efficiently. When pressurizing, the pressure is preferably 0.1 MPa or more and 20 MPa or less, more preferably 0.5 MPa or more and 10 MPa or less, and further preferably 1 MPa or more and 5 MPa or less. The preheating time is not particularly limited as long as the laminated body 25 can be integrated, but is preferably 1 minute or more, more preferably 3 minutes or more, and further preferably 5 minutes or more. is there.

Next, the heat press molding process will be described. The heat press molding is a step of forming a fiber-reinforced resin composite material 10 by heating and pressing the laminate 25 to form a shape.

When the fiber-reinforced resin composite material 10 to be manufactured has a flat shape with the base portion 12 as the base as in the illustrated example, as shown in FIG. 8, the fiber-reinforced resin composite material 10 to be manufactured The laminated body 25 is arranged in the cavity 41 of the mold 40 so as to follow the overall shape. In the example shown in FIG. 8, the laminated body 25 is arranged on the first mold piece 40A of the mold 40 that molds the base portion 12. Then, the laminated body 25 is pressed in the cavity 41 of the mold 40 by approaching and pressing the first mold piece 40A and the second mold piece 40B toward each other. At this time, the laminated body 25 is heated by the mold 40 having a built-in heating source. As a result, the laminated body 25 can be compressed to form the base portion 12. Further, the rib portion 14 can be formed by plastically deforming the laminated body 25 so as to protrude from the base portion 12. In the example shown in FIG. 8, the rib portion 14 can be formed by flowing a part of the laminated body 25 into the recess 41A of the second mold piece 40B. At this time, the thermoplastic resin 32 and the carbon fiber 34 flow in the recess 41A of the second mold piece 40B, so that the rib portion 14 includes the thermoplastic resin 32 and the carbon fiber 34. In this way, the fiber reinforced resin composite material 10 having the base portion 12 and the rib portion 14 is obtained.

According to the heat press molding as described above, the length of the carbon fibers 34 in the prepreg 20 is shortened by cutting the prepreg 20 contained in the laminate 25 in advance. Therefore, the fluidity of the carbon fibers 34 at the time of heat press molding can be ensured. As a result, the flowability of the thermoplastic resin 32 is not hindered by the carbon fibers 34, and the fluidity of the thermoplastic resin 32 is also ensured. As a result, the fiber-reinforced resin composite material 10 including the base portion 12 and the rib portion 14 protruding from the base portion 12 can be heat-press molded with high accuracy. Further, the fiber-reinforced resin composite material 10 obtained by heat press molding has the orientation of the carbon fibers 34 in the direction caused by the orientation direction OD of each prepreg 20 contained in the laminate 25. Therefore, the fiber-reinforced resin composite material 10 has excellent mechanical properties in the direction corresponding to the orientation of the carbon fibers 34 in the laminate 25.

The heating temperature in the heat press molding is not particularly limited as long as it is the temperature at which the thermoplastic resin 32 contained in the laminate 25 melts, but is preferably 180 ° C. or higher and 400 ° C. or lower, and more preferably 185 ° C. or higher and 350 ° C. or higher. It is ℃ or less, more preferably 190 ℃ or more and 300 ℃ or less. Here, the "heating temperature" means the temperature of the mold.

The pressure of heat press molding is preferably 0.5 MPa or more and 20 MPa or less, more preferably 1 MPa or more and 15 MPa or less, and further preferably 2 MPa or more and 10 Ma or less. Further, the pressure at the time of heat press molding may be changed stepwise within the above pressure range. Further, the heat press molding is preferably performed at a pressure higher than that of preheating.

The holding time of the heat press molding is not particularly limited as long as the thermoplastic resin 32 contained in the laminated body 25 can be melted and the rib portion can be formed, but the holding time is preferably 1 minute or more. , More preferably 3 minutes or more, still more preferably 5 minutes or more.

In the heat press molding, the preformed metal layer 17 is arranged in the cavity 41 of the mold 40, and the rib portion 14 and the metal layer 17 are joined at the same time as the base portion 12 and the rib portion 14 are molded. The fiber-reinforced resin composite material 10 provided with the metal layer 17 can be obtained by so-called insert molding.

By the way, the laminate 25 to be heat-press molded includes a plurality of prepregs 20, and each prepreg 20 has an orientation direction OD in which the carbon fibers 34 are oriented. On the other hand, the fiber-reinforced resin composite material 10 has a direction in which it is desired to improve mechanical properties in view of its usage situation and the like, and the rib portion 14 usually has a longitudinal LD along the direction. .. Therefore, in the heat press molding step, it is effective to position the arrangement direction AD of the prepreg 20 included in the laminated body 25 with respect to the longitudinal direction LD of the rib portion 14 to be formed. In the actual heat press molding, the arrangement direction AD of the prepreg 20 included in the laminated body 25 is positioned with respect to the mold 40 having the recess 41A corresponding to the rib portion 14. More specifically, the arrangement direction AD of the prepreg 20 included in the laminated body 25 is relative to the longitudinal direction of the recess 41A of the mold 40 (second mold piece 40B) for forming the target rib portion 14. Will be positioned.

First, the orientation direction OD of the carbon fibers 34 of at least one prepreg 20 contained in the laminate 25 may be parallel to the longitudinal direction LD of the rib portion 14. That is, at the time of heat press molding, the orientation direction OD of the carbon fibers 34 of at least one prepreg 20 contained in the laminate 25 may be parallel to the longitudinal direction of the recess 41A of the mold 40. According to such an example, the carbon fiber 34 flowing in the recess 41A of the mold 40 can be extended along the orientation direction OD of the rib portion 14 of the fiber reinforced resin composite material 10. The carbon fiber 34 extending along the orientation direction OD can effectively enhance the mechanical properties of the rib portion 14 along the orientation direction OD.

Further, the orientation direction OD of the carbon fibers 34 of at least one prepreg 20 contained in the laminate 25 may be orthogonal to the longitudinal direction LD of the rib portion 14. That is, at the time of heat press molding, the orientation direction OD of the carbon fibers 34 of at least one prepreg 20 contained in the laminate 25 may be orthogonal to the longitudinal direction of the recess 41A of the mold 40. According to such an example, the carbon fiber 34 flowing in the recess 41A of the mold 40 can be made to straddle the base portion 12 and the rib portion 14 of the fiber reinforced resin composite material 10. According to the carbon fiber 34 straddling the base portion 12 and the rib portion 14, the bonding strength of the rib portion 14 to the base portion 12 can be effectively strengthened. As a result, it is possible to effectively prevent the rib portion 14 from falling off from the base portion 12 due to an external force or the like during the use of the fiber reinforced resin composite material 10.

In particular, as shown in FIG. 3, the carbon fiber 34 having one end located in the base portion 12 and the other end located in the rib portion 14 tends to easily flow into the vicinity of the tip of the rib portion 14. There is. Therefore, according to the fiber-reinforced resin composite material 10 having such carbon fibers 34, the bonding strength of the rib portion 14 with respect to the base portion 12 can be strengthened more effectively.

It is preferable that the cutting line CT of the prepreg 20 is not orthogonal to the longitudinal LD of the rib portion 14 but is inclined. In particular, when the orientation direction OD of the carbon fibers 34 of at least one prepreg 20 contained in the laminate 25 is orthogonal to the longitudinal direction LD of the rib portion 14, as shown in FIG. 9, the cutting line CT of the prepreg 20 is a rib. It is preferable that the portion 14 is inclined with respect to the longitudinal LD. That is, it is preferable that the cutting line CT of the prepreg 20 is not orthogonal to the longitudinal direction of the recess 41A of the mold 40 but is inclined at the time of heat press molding. In this case, it is possible to prevent the cutting line CT from extending along the rib portion 14 (strictly speaking, the recess 41A of the mold 40 for forming the rib portion 14). If the cutting line CT extends along the rib portion 14, the carbon fiber 34 may be difficult to flow into the rib portion 14 over the entire length of the rib portion 14. By inclining the cutting line CT with respect to the rib portion 14, such a problem can be solved.

Here, FIG. 17 shows the first prepreg in the case where the fiber-reinforced resin composite material 10 shown in FIGS. 1 to 3 is produced by using the laminate 25 including the plurality of prepregs 20 shown in FIG. It is a top view which shows the direction with respect to the fiber reinforced resin composite material 10 to be produced of 20. Similarly, FIG. 18 shows a second prepreg in the case of producing the fiber reinforced resin composite material 10 shown in FIGS. 1 to 3 using the laminate 25 including the plurality of prepregs 20 shown in FIG. It is a top view which shows the direction with respect to the fiber reinforced resin composite material 10 to be produced of 20.

The rib portion 14 of the fiber reinforced resin composite material 10 shown in FIGS. 1 to 3 has a first rib portion 14A extending linearly in the first longitudinal direction LD1 and a second rib portion 14 extending linearly in the second longitudinal direction LD2. The rib portion 14B and the like are included. The first orientation direction OD1 of the prepreg 20 shown in FIG. 17 is parallel to the second longitudinal direction LD2 of the second rib portion 14B. That is, the second orientation direction OD2 of the prepreg 20 shown in FIG. 17 is parallel to the longitudinal direction of the recess of the mold 40 for forming the second rib portion 14B. Therefore, a part of the carbon fibers 34 in the prepreg 20 shown in FIG. 17 flows into the second rib portion 14B and extends in the second longitudinal direction LD2 as shown in FIG. The other part of the carbon fiber 34 in the prepreg 20 shown in FIG. 17 is such that one end is located in the base portion 12 and the other end is located in the first rib portion 14A, as shown in FIG. Become. That is, the prepreg 20 shown in FIG. 17 effectively enhances the mechanical properties of the second rib portion 14B along the second longitudinal direction LD2, and joins the first rib portion 14A to the base portion 12. The strength can be effectively enhanced.

Similarly, the second orientation direction OD2 of the prepreg 20 shown in FIG. 18 is parallel to the first longitudinal direction LD1 of the first rib portion 14A. That is, the second orientation direction OD2 of the prepreg 20 shown in FIG. 18 is parallel to the longitudinal direction of the recess of the mold 40 for forming the first rib portion 14A. Therefore, a part of the carbon fibers 34 in the prepreg 20 shown in FIG. 18 flows into the first rib portion 14A and extends in the first longitudinal direction LD1. The other part of the carbon fiber 34 in the prepreg 20 shown in FIG. 18 has one end located in the base portion 12 and the other end located in the second rib portion 14B. That is, the prepreg 20 shown in FIG. 18 effectively enhances the mechanical properties of the first rib portion 14A along the first longitudinal direction LD1 and joins the second rib portion 14B to the base portion 12. The strength can be effectively enhanced.

That is, according to the example described with reference to FIGS. 17 and 18, the orientation direction OD (first orientation direction OD1) of the carbon fibers 34 of one prepreg 20 contained in the laminate 25 is one rib portion 14. It is parallel to the longitudinal LD (second longitudinal LD2) of (second rib portion 14B). In addition, the orientation direction OD (second orientation direction OD2) of the carbon fiber 34 of the other prepreg 20 included in the laminate 25 is the longitudinal LD of the other rib portion 14 (first rib portion 14A). It is parallel to (first longitudinal direction LD1). According to such an example, the carbon fibers 34 of one prepreg 20 effectively provide mechanical properties along the longitudinal LD (second longitudinal LD2) of one rib portion 14 (second rib portion 14B). And, the bonding strength of the other rib portion 14 (first rib portion 14A) to the base portion 12 can be effectively strengthened. In addition, the carbon fiber 34 of the other prepreg 20 effectively provides mechanical properties along the longitudinal LD (first longitudinal LD1) of the other rib portion 14 (first rib portion 14A). It can be strengthened, and the bonding strength of one rib portion 14 (second rib portion 14B) to the base portion 12 can be effectively strengthened.

Further, in the fiber reinforced resin composite material 10 shown in FIGS. 1 to 3, a plurality of first rib portions 14A are arranged at intervals in the first arrangement direction AD1, and each first rib portion 14A has a first longitudinal direction. It extends in the direction LD1. Then, the carbon fibers 34 contained in one prepreg 20 of the laminate 25 shown in FIG. 17 extend in the first orientation direction OD1 which is non-parallel (particularly orthogonal) to the first longitudinal direction LD1 and the carbon fibers. The average fiber length of 34 is equal to or less than the separation interval DA1 (see FIG. 2) between the two first rib portions 14A adjacent to each other in the first arrangement direction AD1. By setting the average fiber length of the carbon fibers 34 oriented in the first orientation direction OD1 to be equal to or less than the separation interval DA1 of the first rib portion 14A, the end portion of the carbon fiber 34 can easily flow into the first rib portion 14A. be able to. This makes it possible to effectively strengthen the bonding strength of the first rib portion 14A to the base portion 12 of the fiber reinforced resin composite material 10.

Further, in the fiber reinforced resin composite material 10 shown in FIGS. 1 to 3, a plurality of first rib portions 14A are arranged at intervals in the first arrangement direction AD1, and each first rib portion 14A has a first longitudinal direction. It extends in the direction LD1. Further, the plurality of second rib portions 14B are arranged at intervals in the second arrangement direction AD2, and each of the second rib portions 14B extends in the second longitudinal direction LD2. The orientation direction OD (second orientation direction OD2) of the carbon fibers 34 of one prepreg 20 included in the laminate 25 and shown in FIG. 18 is parallel to the first longitudinal direction LD1 of the first rib portion 14A. The average fiber length of the carbon fibers 34 of the prepreg 20 is equal to or less than the separation interval DA2 between the two adjacent second rib portions 14B along the second arrangement direction AD2. Further, the orientation direction OD (first orientation direction OD1) of the carbon fiber 34 of the other prepreg 20 included in the laminate 25 shown in FIG. 17 is parallel to the second longitudinal direction LD2 of the second rib portion 14B. The average fiber length of the carbon fibers 34 of the prepreg 20 is equal to or less than the separation interval DA1 between the two adjacent first rib portions 14A along the first arrangement direction AD1.

According to such an example, the end portion of at least a part of the carbon fibers 34 of the prepreg 20 shown in FIG. 18 can be easily flowed into the second rib portion 14B, and the prepreg shown in FIG. 17 can be easily introduced. At least a part of the ends of the carbon fibers 34 of 20 can easily flow into the first rib portion 14A. In addition, at least a portion of the carbon fibers 34 of the prepreg 20 shown in FIG. 18 can flow into the first rib portion 14A and easily extend into the first longitudinal LD1 as shown in FIG. At least a part of the carbon fibers 34 of the prepreg 20 can flow into the second rib portion 14B and easily extend in the second longitudinal direction LD2. In particular, in the illustrated example, the first arrangement direction AD1 and the first longitudinal direction LD1 are orthogonal, the second arrangement direction AD2 and the second longitudinal direction LD2 are orthogonal, and the first longitudinal direction LD1 and the second longitudinal direction are orthogonal. LD2 is orthogonal. Therefore, at least a part of the carbon fibers 34 of the prepreg 20 shown in FIG. 18 is more effectively promoted to flow into the first rib portion 14A and extend in the first longitudinal direction LD1, and is shown in FIG. At least a part of the carbon fibers 34 of the prepreg 20 flow into the second rib portion 14B and are more effectively promoted to extend the LD2 in the second longitudinal direction. This makes it possible to effectively enhance the mechanical properties of the rib portion 14 in the fiber reinforced resin composite material 10.

In one embodiment described above, the carbon fiber reinforced thermoplastic resin composite material 10 is a carbon fiber reinforced thermoplastic resin composite material having a plurality of carbon fibers 34 and a thermoplastic resin 32, and is a base portion 12 and a carbon fiber reinforced thermoplastic resin composite material. , And a rib portion 14 protruding from the base portion 12. In the carbon fiber reinforced thermoplastic resin composite material 10, at least a part of carbon fibers 34 extend across between the base portion 12 and the rib portion 14. According to such a carbon fiber reinforced thermoplastic resin composite material 10, the joint strength between the base portion 12 and the rib portion 14 can be effectively improved, and the machine excellent in the carbon fiber reinforced thermoplastic resin composite material 10 Characteristic can be imparted.

Further, in one embodiment described above, the carbon fiber reinforced thermoplastic resin composite material 10 is a carbon fiber reinforced thermoplastic resin composite material having a plurality of carbon fibers 34 and a thermoplastic resin 32, and has a base portion. It has a rib portion 12 and a rib portion 14 protruding from the base portion 12. The rib portion 14 has a longitudinal LD along the base portion 12, and at least a part of the carbon fibers 34 are located in the rib portion 14 and extend in the longitudinal LD over the entire length thereof. Usually, the rib portion 14 is provided for the purpose of reinforcement and receives tensile stress in the longitudinal direction thereof. Therefore, the presence of the carbon fibers 34 extending along the longitudinal LD of the rib portion 14 can effectively impart desired mechanical properties to the carbon fiber reinforced thermoplastic resin composite material 10.

Further, in one embodiment described above, the method for producing the carbon fiber reinforced thermoplastic resin composite material has a base portion 12 and a rib portion 14 provided on the base portion 12, and the rib portion 14 has a rib portion 14. This is a method for producing a carbon fiber reinforced thermoplastic resin composite material 10 containing carbon fibers 34. This production method includes a step of cutting the prepreg 20 in which the carbon fibers 34 are oriented in the uniaxial direction UD so that the average fiber length of the carbon fibers 34 is 1 cm or more and 20 cm or less along one or more cutting lines CT. Includes a step of laminating the prepregs 20 and a step of heat-press molding the laminate 25 containing the plurality of cut prepregs 20. According to the heat press molding as described above, the length of the carbon fibers 34 in the prepreg 20 is shortened by cutting the prepreg 20 contained in the laminate 25 in advance. Therefore, the fluidity of the carbon fibers 34 at the time of hot press molding can be ensured. Along with this, the flowability of the thermoplastic resin 32 is not hindered by the carbon fibers 34, and the fluidity of the thermoplastic resin 32 is also ensured. As a result, the fiber-reinforced resin composite material 10 including the base portion 12 and the rib portion 14 protruding from the base portion 12 can be heat-press molded with high accuracy. Further, the fiber-reinforced resin composite material 10 obtained by heat press molding has the orientation of the carbon fibers 34 in the direction caused by the orientation direction OD of each prepreg 20 contained in the laminate 25. Therefore, the fiber-reinforced resin composite material 10 has excellent mechanical properties in the direction corresponding to the orientation of the carbon fibers 34 in the laminate 25.

Although one embodiment has been described by a plurality of specific examples, these specific examples are not intended to limit one embodiment. The above-described embodiment can be implemented in various other specific examples, and various omissions, replacements, changes, additions, and the like can be made without departing from the gist thereof.

For example, the fiber-reinforced resin composite material 10 which has been heat-press-molded may be further cooled-press-molded. By performing the cooling press molding, the shape of the rib portion 14 formed by the heat press molding can be stabilized. The pressure of the cooling press molding is preferably 0.5 MPa or more and 20 MPa or less, more preferably 1 MPa or more and 15 MPa or less, and further preferably 2 MPa or more and 10 MPa or less. The cooling method in the cooling press molding is not particularly limited, and examples thereof include a water cooling method in which running water is allowed to flow in the press plate and the fiber reinforced resin composite material 10 obtained by the heat press molding is pressed by the press plate. In this case, the upper limit of the cooling temperature is preferably 120 ° C. or lower, more preferably 100 ° C. or lower, from the viewpoint of stabilizing the shape of the rib portion 14. The lower limit of the cooling temperature is preferably 50 ° C. or higher, more preferably 60 ° C. or higher, from the viewpoint of facilitating the mold release of the fiber-reinforced resin composite material 10 after molding. The holding time of the cooling press can be the time required for cooling to the above temperature range.

Hereinafter, the present invention will be described in more detail with reference to Examples, but the present invention is not limited to these Examples.

[Example 1]
The carbon fiber reinforced thermoplastic resin composite material according to Example 1 was produced as follows.

A uniaxial carbon fiber prepreg impregnated with a vinyl chloride resin (manufactured by Ronseal, product name: Ronace NP) in a carbon fiber bundle (manufactured by Formosa Plastics Group, product name: TC-35) having 24,000 filaments is flat. A total of 12 sheets were prepared with a visual shape of 210 mm × 210 mm. A laminated body was produced by laminating the prepared 12 prepregs in order. The 12 prepregs were laminated so that the arrangement directions of the carbon fibers in the adjacent prepregs along the stacking direction were orthogonal to each other. Next, each side of the laminated body was cut into seven equal parts by a press cutting machine, and the laminated body was divided into 49 small pieces of the laminated body. Each laminated piece was made to have a planar shape of 30 mm × 30 mm. However, the positions and orientations of the 49 laminated small pieces were maintained unchanged. That is, the position and orientation of each laminate piece with respect to the other laminate pieces were kept unchanged before and after cutting the laminate. Then, heat press molding was carried out for 7 minutes using a mold set at 195 ° C. to prepare a carbon fiber reinforced thermoplastic resin composite material similar to those in FIGS. 1 to 3.

The shape of the carbon fiber reinforced thermoplastic resin composite material to be manufactured is as follows. The plane shape of the base portion was a square shape of 214 mm × 214 mm, and the thickness was 0.8 mm. The rib portions are three first rib portions arranged at a distance of 50 mm in the first arrangement direction parallel to one side of the base portion, and a first rib portion orthogonal to the first arrangement direction and parallel to the other side of the base portion. It was made to have three second rib portions arranged at a distance of 50 mm in the two arrangement directions. Each first rib portion extends linearly in the first longitudinal direction orthogonal to the first arrangement direction, and each second rib portion 14B extends linearly in the second longitudinal direction orthogonal to the second arrangement direction. The rib portion has a tapered shape so that both side surfaces are inclined by 1 ° with respect to the normal direction in a cross section orthogonal to the longitudinal direction thereof. The width at the tip (end) farthest from the base of the rib portion was set to 1 mm.

[Example 2]
The carbon fiber reinforced thermoplastic resin composite material according to Example 2 was produced as follows.

Twelve prepregs similar to those in Example 1 were prepared. Next, each side of the prepreg was cut into seven equal parts with a press cutting machine, and the prepreg was divided into 49 pieces. Each prepreg piece was made to have a planar shape of 30 mm × 30 mm. However, the positions and orientations of the 49 prepreg pieces were maintained unchanged. That is, the position and orientation of each prepreg piece with respect to the other prepreg pieces did not change before and after cutting the prepreg.

Then, 12 cut prepregs were laminated in order to prepare a laminated body. In each of the cut prepregs contained in the laminated body, the positions and orientations of the arbitrary prepreg pieces with respect to the other prepreg pieces were the same as those before cutting the prepreg. The twelve prepregs were arranged so that the arrangement directions of the carbon fibers in the adjacent prepregs along the stacking direction were orthogonal to each other. However, when stacking each cut prepreg, the position of the outer shape in the projection in the stacking direction is shifted by 15 mm in each of the two orthogonal directions with respect to the cut prepreg placed (stacked) immediately before. .. Specifically, the first cut prepreg is arranged so that each side extends vertically and horizontally, and then 15 mm on both the right and upper sides of the outer shape of the first cut prepreg. The second cut prepreg was laminated on the first cut prepreg so as to shift the outer shape. After that, when stacking the third to twelfth cut prepregs, the positions of the outer shapes of the odd-numbered cut prepregs should be the same as those of the first cut prepreg in the projection in the stacking direction. Laminated in. On the other hand, the fourth, sixth, eighth, tenth, and twelfth cut prepregs are projected to the right and bottom of the odd-numbered cut prepregs in the stacking direction, respectively. The outer shapes were shifted by 15 mm on both the left and the bottom, the left and the top, the right and the top, and the right and the bottom, and the layers were laminated.

The laminate obtained as described above was heat-press molded in the same manner as in Example 1 to prepare a carbon fiber reinforced thermoplastic resin composite material.

[Comparative Example 1]
The laminate prepared in the same manner as in Example 1 except that it was not cut was heat-press molded in the same manner as in Example 1 to prepare a carbon fiber reinforced thermoplastic resin composite material.

[Comparative Example 2]
The carbon fiber reinforced thermoplastic resin composite material according to Comparative Example 2 was produced as follows.

Twelve prepregs similar to those in Example 1 were prepared. A laminated body was produced by laminating the prepared 12 prepregs in order. In this laminate, the arrangement directions of the carbon fibers in the 12 prepregs were made parallel. Next, each side of the laminate was cut into seven equal parts, and the laminate was divided into 49 small pieces by a press cutting machine. After dropping the laminate containing the prepreg pieces divided into 588 (= 49 × 12) pieces from a position of 30 cm in height and randomly arranging the prepreg pieces, the prepreg pieces are manually arranged so that the thickness becomes uniform. Was leveled to prepare a workpiece containing a large number of randomly arranged prepreg pieces. The work piece obtained as described above was heat-press molded in the same manner as in Example 1 to prepare a carbon fiber reinforced thermoplastic resin composite material.

[Evaluation 1: 4-point bending test]
A 4-point bending test was performed using a precision universal testing machine (AG-IS 100kN manufactured by Shimadzu Corporation) in accordance with JIS K 7171 and JIS K 7017. A 5 kN load cell was used. Regarding the dimensions of the test piece, the total length was set to 100 mm in consideration of the test piece slipping off from the bending jig at the time of large deflection, and the width of the test piece was set to 20 mm in consideration of the cut length of the CFRTP chop of 30 mm. The distance between the fulcrums was 16 times the plate thickness as specified. By such a method, 5 test pieces were evaluated for each of Example 1, Example 2, Comparative Example 1 and Comparative Example 2, and the average value of the bending strength (MPa) obtained as the test result was shown in Table 1. It is shown in the column of "bending strength (MPa)".

[Evaluation 2: Visual evaluation of appearance]
In the obtained carbon fiber reinforced thermoplastic resin composite material, there is a part where the end (tip) of the rib portion is sufficiently molded by the resin and the carbon fiber is not filled and the color peculiar to the resin remains. Visual confirmation was performed at two points. When only the milky white part peculiar to the vinyl chloride resin was confirmed, it was judged that the impregnation of carbon fiber was insufficient. Table 1 shows the results of confirming which of the following "○", "△" and "×" the appearance evaluations of Example 1, Example 2, Comparative Example 1 and Comparative Example 2 correspond to. Shown in the "Appearance evaluation" column.
◯: A resin containing carbon fiber is impregnated up to the end of the rib portion. There are no cracks or chips on the ribs, and the color of the resin alone is not confirmed.
Δ: Resin is impregnated up to the end of the rib portion, but it is confirmed that some carbon fibers are not sufficiently impregnated.
X: Cracks and chips are confirmed on the rib part.

UD Uniaxial direction ND Normal direction DD Stacking direction OD Orientation direction OD1 First orientation direction OD2 Second orientation direction OD3 Third orientation direction OD4 Fourth orientation direction CT Cutting line CT1 First cutting line CT2 Second cutting line CT3 Third cutting Line CT4 4th cutting line AD Arrangement direction AD1 1st arrangement direction AD2 2nd arrangement direction LD Longitudinal LD1 1st longitudinal LD2 2nd longitudinal DA1 Separation interval DA2 Separation interval 10 Carbon fiber reinforced thermoplastic resin composite material (fiber reinforced) Resin composite material)
12 Base part 14 Rib part 14A 1st rib part 14B 2nd rib part 16 Resin layer 17 Metal layer 20 prepreg 22 Cut prepreg 23 prepreg piece 25 Laminated body 32 Thermoplastic resin 34 Carbon fiber 40 Mold 40A First mold piece 40B 2nd mold piece 41 cavity

Claims (7)

A step of cutting a prepreg in which carbon fibers are oriented in the uniaxial direction so that the average fiber length of the carbon fibers is 1 cm or more and 20 cm or less.
The process of laminating multiple prepregs to form a laminate,
A laminate containing a plurality of cut prepregs is heat-press molded, and the base portion and the carbon fiber reinforced thermoplastic that is integrally molded with the base portion and protrudes from the base portion and contains the carbon fibers. A method for producing a carbon fiber reinforced thermoplastic resin composite material, which comprises a step of producing a resin composite material. Any cutting line contained in one of the two cut prepregs adjacent to the laminated body in the stacking direction is all the cutting lines contained in the other of the two cut prepregs in the projection in the stacking direction. The method for producing a carbon fiber reinforced thermoplastic resin composite material according to claim 1, which is at least partially deviated from. The method for producing a carbon fiber-reinforced thermoplastic resin composite material according to claim 1 or 2, wherein the orientation directions of the carbon fibers of the plurality of prepregs contained in the laminate are 1 or more and 4 or less. Any of claims 1 to 3, wherein the ratio (H / T) of the protrusion height H [mm] of the rib portion from the base portion to the thickness T [mm] of the rib portion is 10 or more and 500 or less. The method for producing a carbon fiber reinforced thermoplastic resin composite material according to item 1. The rib portion has a longitudinal direction along the base portion and has a longitudinal direction.
The carbon fiber reinforced thermoplastic according to any one of claims 1 to 4, wherein the orientation direction of the carbon fibers of at least one prepreg contained in the laminate is parallel or orthogonal to the longitudinal direction of the rib portion. A method for manufacturing a resin composite material. The method for producing a carbon fiber reinforced thermoplastic resin composite material according to any one of claims 1 to 5, wherein the base portion and the rib portion are integrally molded. A carbon fiber reinforced thermoplastic resin composite material having a plurality of carbon fibers and a thermoplastic resin.
With the base part
A rib portion protruding from the base portion is provided.
A carbon fiber reinforced thermoplastic resin composite material in which at least a part of carbon fibers extends across the base portion and the rib portion.

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