JP5640357B2 - Fiber-reinforced composite material molded article and method for producing the same - Google Patents

Description

  The present invention relates to a fiber reinforced composite material molded article made of a fiber reinforced composite material such as a prepreg or a sheet molding compound (SMC), and a manufacturing method thereof.

  Conventionally, for example, a prepreg made by impregnating a thermosetting resin into substantially continuous reinforcing fibers and a sheet molding compound (SMC) made by impregnating short fiber-like reinforcing fibers with thermosetting resin are stacked on each other. A technique for obtaining a fiber-reinforced composite material molded article having a predetermined shape by setting them in a molding die and heating and pressurizing them is known (for example, see Patent Document 1). There is also a technique for obtaining a hollow fiber-reinforced composite material molded article by winding a core material with prepreg or SMC and applying heat and pressure to the core material (see, for example, Patent Document 2).

International Publication No. 04/48435 Pamphlet JP-A-5-337966

By the way, in a molded product using a normal prepreg, a solid shape portion having a predetermined strength such as a clip seat surface may be provided on one side surface of the flat main body portion. The three-dimensionally shaped portion includes, for example, an upper wall that is separated from one side surface of the main body portion, a support wall that extends from the outer edge of the upper wall toward the main body portion, and one side surface of the main body portion from the tip edge of the support wall. A hollow shape having a plate-like portion that extends is formed, and the plate-like portion is welded in surface contact with one side surface of the main body portion, whereby the three-dimensional shape portion is firmly fixed to the main body portion.
In this case, in order to familiarize the prepreg with the outer surface of the core for forming the three-dimensional shape portion, it is common to provide a cut in the prepreg. At this time, it is necessary to provide different cuts for each prepreg so that the cuts are not overlapped and the strength of the three-dimensional shape portion is not lowered when a plurality of prepregs are stacked. As a result, the number of cut patterns of the prepreg increases and the laminating work becomes complicated, resulting in a problem of reducing work efficiency.
On the other hand, it is conceivable to form the three-dimensional shape part using SMC that is easy to adjust to the mold, but in this case, since the main body part is formed of prepreg from the aspect of ensuring the strength, the SMC is faced to the main body part (prepreg). It will be necessary to contact and weld. Then, there is a problem that sink marks are generated on the other side surface (design surface) of the main body due to a difference in curing shrinkage rate between the two materials, and the appearance is deteriorated.

  In view of this, the present invention provides a molded article of fiber reinforced composite material and a method for manufacturing the same, and allows a three-dimensional shape portion having a predetermined strength to be easily formed on one side surface of a flat main body portion. The purpose is to prevent the occurrence of sink marks on the other side.

As means for solving the above problems, the invention described in claim 1
In the fiber reinforced composite material molded product formed by projecting a three-dimensional shape part on the surface of the main body part composed of a prepreg laminate ,
The three-dimensionally shaped portion has an upper wall spaced from the surface of the main body portion, a support wall extending from the outer edge of the upper wall toward the main body portion, and a plate extending from the front end edge of the support wall along the surface of the main body portion. And consists of
The outer surface side of the three-dimensional shape part is molded by prepreg, and the inner surface side of the upper wall and the support wall is reinforced by a sheet molding compound,
And the said plate-shaped part is shape | molded only by a prepreg, and this plate-shaped part is surface-contacted and integrated with the surface of a main-body part.
The invention described in claim 2
The plate-like portion is composed of an outer layer made of a prepreg for molding the outer surface side of the three-dimensionally shaped portion, and an inner layer made of a prepreg sandwiched between the outer layer and the main body portion,
The inner layer is sandwiched between an end of the sheet molding compound on the main body side and the main body.
The invention described in claim 3
In the manufacturing method of the fiber reinforced composite material molded product formed by projecting a three-dimensional shape part on the surface of the main body part,
A prepreg for main body molding is arranged in the molding die of the molded product, and a core for molding a three-dimensional shape portion, a sheet molding compound, and a prepreg are sequentially arranged on the surface of the prepreg,
Only the prepreg for forming the three-dimensional shape part is provided with a plate-like part extending along the surface of the prepreg for forming the main body part,
In a state where the plate-like portion is brought into surface contact with the surface of the prepreg for forming the main body portion directly or indirectly through another prepreg, the respective materials are integrated and cured to obtain the molded product.

According to the present invention, by forming a part of the thickness of the three-dimensional shape portion with a sheet molding compound having a relatively high formability (fluidity), the strength and thickness of the three-dimensional shape portion are ensured, It is possible to reduce the labor of stacking a plurality of prepregs having different cuts when forming a three-dimensionally shaped part that requires shaping, to improve work efficiency and to reduce costs.
Moreover, the main body part whose design property is questioned by comprising only the prepreg which has the shrinkage | contraction rate equivalent to a main-body part in the joining (welding) part of the solid-shaped part welded in surface contact with one side surface of a main-body part Occurrence of sink marks on the other side surface (design surface) can be suppressed, and the molded product having excellent appearance can be obtained.

It is a perspective view of the principal part of the fiber reinforced composite material molded article in the Example of this invention. It is sectional drawing of the said fiber reinforced composite material molded article and its shaping | molding die. It is sectional drawing of the modification of the said fiber reinforced composite material molded article. It is a perspective view of the prepreg for three-dimensional shape part shaping | molding of the said fiber reinforced composite material molded article, (a) is the state which provided the notch in the sheet-like prepreg, (b) is the state which raised the notch part of the said prepreg , (C) shows the state after molding of a fiber-reinforced composite material molded product.

  Embodiments of the present invention will be described below with reference to the drawings. For convenience of explanation, it is assumed that the arrow FR indicates the front, the arrow LH indicates the left, and the arrow UP indicates the upward.

  1 and 2 show a main part of a fiber-reinforced composite material molded product 1 used, for example, on the inner side of an A-pillar of an automobile. The fiber-reinforced composite material molded product 1 integrally includes, for example, a flat plate-like main body portion 2 and a three-dimensional shape portion 3 that protrudes in a hollow shape on one side surface 2a (surface) of the main body portion 2. The other side surface 2b of the main body 2 forms a flat design surface exposed to the inside of the vehicle (hereinafter, the other side surface 2b may be referred to as a design surface 2b). On the other hand, the three-dimensional shape part 3 forms the clip seating surface 5 for coupling | bonding with other components, for example in the side which is not exposed to the vehicle inside. The design surface 2b is not limited to a flat surface, but includes a curved surface.

  In this embodiment, the fiber reinforced composite material molded article 1 is formed by appropriately arranging two types of unreinforced fiber reinforced resin in the mold 20 and applying pressure and heating with, for example, an autoclave. The molded product 1 is welded and cured.

The main body 2 is formed in a flat plate shape having a predetermined thickness, for example, by laminating a plurality of sheet-like unidirectional prepregs (or cross prepregs).
On the other hand, the three-dimensionally shaped portion 3 has, for example, a rectangular shape in plan view and is raised from the main body portion 2, and an edge of the outer shell 3 a on the main body portion 2 side along one side surface 2 a of the main body portion 2. It has the flat plate part 3b extended.

  One side of the outer shell 3a opens toward one side in the direction along the surface of the main body 2 (the front in the figure), and a flat upper wall 6 that is separated from one side 2a of the main body 2 and the upper shell 6a. A flat left and right inclined wall 7 extending diagonally downward and outward from the left and right side edges of the wall 6 toward the main body 2, and a flat plate rear extending diagonally downward and rearward from the rear edge of the upper wall 6 toward the main body 2 And an inclined wall 8.

The upper wall 6 is substantially parallel to the side surface 2 a of the main body 2 and forms the clip seat surface 5. A slit-shaped notch 6 a for holding a clip is provided on the front side of the left and right intermediate portion of the upper wall 6.
The flat plate portion 3b extends along one side surface 2a of the main body portion 2 from the end edge of the inclined walls 7 and 8 on the main body portion 2 side, and the flat plate portion 3b is in surface contact with the one side surface 2a of the main body portion 2. Then, the three-dimensional shape portion 3 is integrally fixed to the main body portion 2 by being welded.

  Here, the outer shell 3a of the three-dimensional shape portion 3 is formed by a prepreg on the outer surface side thereof, while the inner surface side is formed by a sheet molding compound (a resin containing cut reinforcing fibers, hereinafter referred to as SMC). A two-layer structure is formed.

The prepreg layer 14 a constituting the outer surface side of the outer shell 3 a is made of, for example, a single prepreg having a curing shrinkage rate equivalent to that of the prepreg for forming the main body 2.
On the other hand, the SMC layer 14b (reinforcing layer) constituting the inner surface side of the outer shell 3a has a different curing shrinkage rate from that of the prepreg for molding the main body 2.

  The flat plate portion 3b has a U-shape in plan view and extends outside the edge of the outer shell 3a on the main body portion 2 side. The flat plate portion 3 b includes an outer layer 16 that extends outward from a prepreg layer 14 a that forms the outer surface side of the outer shell 3 a, and an inner layer 17 that includes a prepreg sandwiched between the outer layer 16 and the main body portion 2. Similarly to the outer layer 16, the prepreg constituting the inner layer 17 has a curing shrinkage rate equivalent to that of the prepreg for molding the main body 2. That is, the flat plate portion 3 b is composed only of a prepreg having a curing shrinkage rate equivalent to that of the main body portion 2.

  The inner layer 17 has a flat plate shape, and is provided with an arbitrary thickness so that the flat plate portion 3b has a thickness equivalent to that of the outer shell 3a. The inner edge 17a of the inner layer 17 (prepreg) is sandwiched between the edge of the SMC layer 14b on the main body 2 side and one side surface 2a of the main body 2 (prepreg), so that the SMC layer 14b and the main body Direct contact with 2 (prepreg) is avoided. Then, in this state, the flat plate portion 3b is brought into surface contact with the one side surface 2a of the main body portion 2 and welded, so that the three-dimensional shape portion 3 is in the state in which the SMC layer 14b is held by the prepreg layer 14a from the outer surface side. The unit 2 is integrally fixed.

The prepreg is formed by impregnating a substantially continuous reinforcing fiber with a thermosetting resin.
Examples of the reinforcing fiber include carbon fiber, glass fiber, aramid fiber, high-strength polyester fiber, boron fiber, alumina fiber, silicon nitride fiber, and nylon fiber. Among these, carbon fiber is preferable because it is excellent in specific strength and specific elasticity.
Examples of the thermosetting resin include epoxy resins, unsaturated polyester resins, acrylic resins, vinyl ester resins, phenol resins, and benzoxazine resins. Among these, an epoxy resin is preferable because the strength after curing can be increased.

Further, the prepreg may contain various additives such as a curing agent, a release agent, a defoaming agent, an ultraviolet absorber, and a filler.
The number of prepregs laminated is preferably 2-20. If the number of prepregs laminated is 2 or more, a sufficiently strong molded product can be obtained, and if it is 20 or less, the cost of the molded product can be suppressed.

On the other hand, the sheet molding compound is formed by impregnating a thermosetting resin into a short fiber-like reinforcing fiber which is usually cut to 12 to 50 mm.
Examples of the reinforcing fiber include carbon fiber, glass fiber, aramid fiber, high-strength polyester fiber, boron fiber, alumina fiber, silicon nitride fiber, and nylon fiber. Among these, carbon fiber is preferable because it is excellent in specific strength and specific elasticity. Further, the reinforcing fiber used for the prepreg and the reinforcing fiber used for the sheet molding compound may be the same or different.
Examples of the thermosetting resin include epoxy resins, unsaturated polyester resins, acrylic resins, vinyl ester resins, phenol resins, and benzoxazine resins. Among these, vinyl ester resins are preferred because they can be cured quickly. Moreover, the thermosetting resin used for the prepreg and the thermosetting resin used for the sheet molding compound may be the same or different.

  The outer shell 3a is composed of two layers of the SMC layer 14b and the prepreg layer 14a. When the outer shell 3a having a predetermined thickness is formed only by laminating a plurality of prepregs, the number of cut patterns of the prepreg increases. This is because the work is complicated, and on the other hand, if the number of prepregs is reduced, it becomes difficult to ensure the strength and thickness of the clip seat surface 5. Further, when the outer shell 3a is formed only by SMC, it is necessary to form the flat plate portion 3b for fixing the outer shell 3a to the main body portion 2 by SMC, and the flat plate portion 3b is brought into surface contact with the main body portion 2 and welded. This is because sink marks are generated on the design surface 2 b of the main body 2.

  Therefore, by forming a large part of the thickness of the three-dimensionally shaped portion 3 (outer shell 3a) with SMC having relatively high formability (fluidity) and arranging the prepreg only on the outer surface, the number of cut patterns of the prepreg In addition to simplifying the laminating operation by suppressing the increase in the thickness, it is easy to ensure the strength and thickness of the clip seating surface 5, and by using the flat plate portion 3 b made of only the prepreg for fixing the three-dimensional shape portion 3, The fixing strength of the shape portion 3 (outer shell 3a) to the main body portion 2 can be secured, and only the prepreg having the same curing shrinkage rate is welded to the main body portion 2 while being in surface contact with the main body portion 2. The occurrence of sink marks on the design surface 2b can be prevented.

  FIG. 2 shows an example in which the outer shell 3a and the flat plate portion 3b have the same thickness. In this case, it is possible to use a conventional molding die 20 in which a plurality of prepregs are stacked to form the three-dimensional shape portion 3. The inner layer 17 has a U-shape in plan view similar to that of the flat plate portion 3 b, and the inner edge portion 17 a extends inward from the inner edge portion of the outer layer 16. The inner edge 17a is interposed between the SMC layer 14b and the main body 2 (prepreg) because the end edge of the SMC layer 14b on the main body 2 side abuts on the inner edge 17a. Direct contact of the layer 14b with the main body 2 (prepreg) is completely avoided, and the occurrence of sink marks on the design surface 2b of the main body 2 is more reliably prevented.

  On the other hand, the fiber reinforced composite material molded product 1 ′ in FIG. 3 eliminates the inner layer 17 from the fiber reinforced composite material molded product 1 and suppresses the thickness of the flat plate portion 3 b with respect to the outer shell 3 a of the three-dimensional shape portion 3. It is a thing. In this case, only the edge of the SMC layer 14b on the main body portion 2 side comes into contact with the main body portion 2, but the reason is that the contact area is small compared to the case where the SMC layer 14b is in surface contact with the main body portion 2. As described above, the occurrence of sink marks on the design surface 2b of the main body 2 is prevented, and the cost can be reduced by simplifying the configuration.

Next, an example of a method for producing the fiber-reinforced composite material molded article 1 (and 1 ′) will be described with reference to FIGS.
First, a release agent (for example, MR-3 manufactured by Chem Lease Co., Ltd.) is applied to the CFRP lower mold 21 manufactured in a desired shape, and a prepreg 12 (for example, TRK510 321GMP manufactured by Mitsubishi Rayon Co., Ltd.) is formed thereon. The epoxy resin used has a curing shrinkage of about 3%).

  Next, at a predetermined position on one side surface of the laminated prepreg 12, a slide mold 23 produced by cutting out the same material as the lower mold 21 into a desired shape is disposed, and on a plane portion around the slide mold 23, A prepreg 15 for forming the inner layer 17 cut into a desired shape is disposed (the prepreg 15 is not necessary in the case of the molded product 1 ′), and the outer surface of the slide mold 23 is used for molding the inner surface 3 a of the outer shell 3 a of the three-dimensional shape portion 3. CF-SMC13b (for example, AMC8590BK manufactured by Quantum, the curing shrinkage of the vinyl ester resin used is about 10%), and a predetermined notch 25 is provided so as to cover the slide mold 23 and the SMC13b from above. The put prepreg 13a was placed.

  Next, a release agent was applied to the CFRP upper mold 22 having a predetermined shape, which was then placed on the lower mold 21 to sandwich the stack, and the outer periphery of the mold was appropriately fixed by the fastening means 24 or the like. In this state, the stack together with the mold 20 is put into the autoclave and subjected to predetermined pressure heat treatment (80 ° C. × 20 minutes → 130 ° C. × 60 minutes, temperature increase 1.5 ° C./min, 6 atm). The stack in the mold was cured. Thereafter, the molding die 20 was taken out from the autoclave, and the stack was removed from the mold to obtain the desired integral molded product 1.

  The SMC 13b for forming the three-dimensional shape portion 3 has a high fluidity (shaping property), and therefore can be set in the mold with almost the same material shape. However, the prepreg 13a for forming the three-dimensional shape portion 3 is shown in FIG. As shown in FIG. 4A, for example, a Y-shaped cut 25 in a plan view is provided, and the circumference of the cut 25 is widened so as to be widened (see FIG. 4B), so that the prepreg 13a is attached to the outer surface of the slide mold 23. Adapt to shape. At this time, the lower part of the Y-shaped notch 25 forms the notch 6a for holding the clip. The inside of the expanded cut 25 is filled with SMC 13b during pressurization and heating of each material, and after forming the fiber reinforced composite material molded article 1, the outer shell 3a including the flat upper wall 6 by the prepreg 13a and the SMC 13b. Is formed.

  As described above, the fiber-reinforced composite material molded article 1, 1 ′ in the above embodiment is formed by projecting the three-dimensional shape portion 3 having a predetermined strength on one side surface 2a of the flat main body portion 2 made of prepreg. The three-dimensionally shaped portion 3 includes an upper wall 6 that is separated from one side surface 2a of the main body portion 2, and inclined walls 7 and 8 that extend from the outer edge of the upper wall 6 toward the main body portion 2, Each of the inclined walls 7 and 8 has a hollow shape including a flat plate portion 3b extending along one side surface 2a of the main body portion 2 from the leading edge of the main body portion 2, and the outer surface side of the three-dimensional shape portion 3 is formed by a prepreg 13a. The inner surface side of the wall 6 and the support wall is reinforced by the sheet molding compound 13b, and the flat plate portion 3b is formed only by the prepregs 13a and 15 (or only the prepreg 13a), and the flat plate portion 3b is formed on one side surface 2a of the main body portion 2. In Contact with those to be welded.

  When manufacturing this fiber-reinforced composite material molded product 1, 1 ′, first, the prepreg 12 for molding the main body 2 is placed in the mold 20, and the three-dimensional shaped part 3 for molding is formed on one side of the prepreg 12. The slide mold 23, the sheet molding compound 13b, and the prepreg 13a are arranged in order, and only the prepreg 13a for forming the three-dimensionally shaped portion 3 is provided with a flat plate portion 3b extending along one side surface of the prepreg 12 for forming the main body portion 2. In a state where the flat plate portion 3b is brought into surface contact with one side surface of the prepreg 12 for molding the main body portion 2 directly or indirectly through another prepreg 15, the respective materials are integrally welded and cured, and the molded product 1, You will get 1 '.

According to this structure, the strength and thickness of the three-dimensional shape portion 3 are ensured by molding a part of the thickness of the three-dimensional shape portion 3 with the sheet molding compound 13b having relatively high formability (fluidity). In the above process, it is possible to reduce the labor of stacking a plurality of prepregs having different cuts 25 when forming the three-dimensionally shaped portion 3 whose shapeability is required, to improve work efficiency and to reduce costs.
Further, only the prepregs 13a and 15 having the same contraction rate as that of the main body 2 (or only the prepreg 13a) are used as the joining (welding) portion of the three-dimensionally shaped portion 3 which is welded in contact with the one side surface 2a of the main body 2. By comprising, the generation | occurrence | production of the sink of the other side surface (design surface) 2b of the main-body part 2 in which design property is asked can be suppressed, and the said molded products 1 and 1 'excellent in the external appearance property can be obtained.

Further, in the fiber reinforced composite material molded product 1, the flat plate portion 3 b is sandwiched between an outer layer 16 composed of a prepreg 13 a that molds the outer surface side of the three-dimensional shape portion 3, and the outer layer 16 and the main body portion 2. The inner layer 17 is composed of a prepreg 15, and the inner layer 17 is sandwiched between the body portion 2 side edge of the sheet molding compound 13 b and the body portion 2, so that the body portion 2 (prepreg of the sheet molding compound 13 b The direct contact to 12) can be completely avoided, and the occurrence of sink marks on the design surface 2b of the main body 2 can be more reliably prevented.
On the other hand, in the fiber reinforced composite material molded product 1 ′, the flat plate portion 3 b is composed only of the prepreg 13 a that molds the outer surface side of the three-dimensional shape portion 3, thereby causing the design surface 2 b of the main body portion 2 to sink. It is possible to reduce the cost by simplifying the configuration while preventing it.

The present invention is not limited to the above embodiment. For example, if the three-dimensional shape portion 3 is an open shape, the detachable slide mold 23 can be used as in the above embodiment, but the three-dimensional shape portion 3 is a closed shape. If so, a core material such as a foam core may be used.
And the structure in the said Example is an example of this invention, and it cannot be overemphasized that a various change is possible in the range which does not deviate from the summary of the said invention.

1, 1 'Fiber reinforced composite material molded product 2 Main body 2a One side 3 Solid shape 3b Flat plate (plate-shaped part)
6 Upper wall 7 Left and right inclined wall (support wall)
8 Rear inclined wall (support wall)
12, 13a, 15 Prepreg 13b Sheet molding compound (SMC)
16 Outer layer 17 Inner layer 20 Mold 23 Slide type (core)

Claims (3)

In the fiber reinforced composite material molded product formed by projecting a three-dimensional shape part on the surface of the main body part composed of a prepreg laminate ,
The three-dimensionally shaped portion has an upper wall spaced from the surface of the main body portion, a support wall extending from the outer edge of the upper wall toward the main body portion, and a plate extending from the front end edge of the support wall along the surface of the main body portion. And consists of
The outer surface side of the three-dimensional shape part is molded by prepreg, and the inner surface side of the upper wall and the support wall is reinforced by a sheet molding compound,
A fiber-reinforced composite material molded product in which the plate-like portion is formed only from a prepreg, and the plate-like portion is in surface contact with the surface of the main body to be integrated. The plate-like portion is composed of an outer layer made of a prepreg for molding the outer surface side of the three-dimensionally shaped portion, and an inner layer made of a prepreg sandwiched between the outer layer and the main body portion,
The fiber-reinforced composite material molded article according to claim 1, wherein the inner layer is sandwiched between an end of the sheet molding compound on the main body side and the main body. In the manufacturing method of the fiber reinforced composite material molded product formed by projecting a three-dimensional shape part on the surface of the main body part,
A prepreg for main body molding is arranged in the molding die of the molded product, and a core for molding a three-dimensional shape portion, a sheet molding compound, and a prepreg are sequentially arranged on the surface of the prepreg,
Only the prepreg for forming the three-dimensional shape part is provided with a plate-like part extending along the surface of the prepreg for forming the main body part,
A fiber-reinforced composite material in which each material is integrated and cured to obtain the molded product in a state where the plate-like portion is in surface contact with the surface of the prepreg for forming the main body portion directly or indirectly through another prepreg. Manufacturing method of molded products.

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