JP2005288756A - Method for producing fiber-reinforced resin molding - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method for producing a fiber-reinforced resin molding which can easily mold a molding having a complex shape without a defect such as a void. <P>SOLUTION: The method for producing the fiber-reinforced resin molding has a step (D) for inserting a flexible cowl plate having a radius of curvature smaller than that of the bottom surface of a flexible upper mold between a lower mold and the upper mold which is fitted into the lower mold and the bottom surface of which is formed to have a radius of curvature smaller than that of the inner bottom surface of the lower mold and a prepreg below the cowl plate, a step (E) in which the upper mold is pressed in the lower mold direction, the prepreg is pressed to a point or along a line, the cowl plate is molded to imitate the lower mold while being deformed, and the space between the upper mold and the lower mold is decompressed, and a step (F) for curing the prepreg by heating. The cowl plate can be excluded. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a method for producing a fiber-reinforced resin molded body having a complicated shape.

  Fiber reinforced resin moldings are lightweight and have high rigidity, and are used for relatively large parts such as furniture such as bathtubs and washstands, sports equipment, automobile parts, aircraft parts, and the like.

  As a method for producing a fiber reinforced resin composite material having a relatively large and complicated shape, a bag molding method is generally used.

  As a bag molding method, a plurality of prepregs are laid on top of each other on the inner surface of the mold cavity, and the bag is inflated by filling a fluid in the inflatable bag placed inside thereof, so that the prepreg is placed on the inner surface of the mold. There has been proposed a method (Patent Document 1) in which the prepreg is cured by bringing it into close contact and heating in that state.

  Alternatively, as a bag forming method, there is disclosed a method (Patent Document 2) in which gas is filled in a bag after reducing the pressure between the mold and the bag.

However, in the conventional bag forming method, a gap is generated in the overlapping part of the prepregs laid on the mold, or the overlapping part is undulated when the vertical lengths of the prepregs stacked vertically are not equal. However, there are problems such as the case where the surface of the resulting molded body is not smooth, the formation of voids in the molded body, and the problem of increased cost.
JP-A-9-70843 (Claim 1) JP-A-5-329856 (Claim 1)

  An object of the present invention is to provide a method for easily producing a fiber reinforced resin molded article having a complicated shape and a smooth surface free from defects such as voids without performing complicated operations.

  As a result of diligent research, the present inventor has found that an upper mold having flexibility in which the lower bottom surface is formed with a smaller radius of curvature than the curvature radius of the inner bottom surface of the lower mold, or the lower bottom surface is a curvature radius of the inner bottom surface of the lower mold. Using a flexible cowl plate formed with a smaller radius of curvature than the first, centered on one point or a line of points in the mold, and the pressed part of the mold from this point or line into the lower mold By deforming the upper die or cowl plate so that it spreads along the bottom surface, the prepreg is shaped to follow the lower die, making it easy to reinforce complex shaped fibers without creating voids and undulations in the molded product. The present inventors have found that a resin molded body can be produced and have completed the present invention.

  The present invention for solving the above problems is described below.

  [1] Between a lower mold and an upper mold having flexibility that is inserted into the lower mold, the bottom surface of which is formed with a smaller radius of curvature than the curvature radius of the inner bottom surface of the lower mold Step (A) of inserting the prepreg, and then pressing the upper mold in the lower mold direction, pressing the prepreg along one point or line, forming the upper mold while following the lower mold while deforming the upper mold and lower The manufacturing method of the fiber reinforced resin molding which has the process (B) which makes pressure reduction between molds, and the process (C) which heats after that and hardens a prepreg.

  [2] Between a lower mold and an upper mold having flexibility and fitted into the lower mold, the bottom surface of which is formed with a smaller radius of curvature than the radius of curvature of the inner bottom surface of the lower mold A step (D) of inserting a flexible cowl plate having a smaller radius of curvature than the bottom surface of the upper die, and further inserting a prepreg below the cowl plate, and then pressing the upper die toward the lower die at one point or line (E) in which the pressure is applied along the lower die while deforming the cowl plate and the pressure between the upper die and the lower die is reduced, and then the prepreg is cured by heating (F) And a method for producing a fiber-reinforced resin molded body.

  [3] The method for producing a fiber-reinforced resin molded product according to [1] or [2], wherein the fiber-reinforced resin molded product has a three-dimensional structure.

  According to the present invention, it is possible to obtain a molded product having a complicated shape made of a fiber-reinforced resin composite material having a smooth surface without generating undulations or voids in the overlapping portion of the prepreg.

  Automatic continuous molding becomes possible by the method for manufacturing a fiber-reinforced resin molded body of the present invention, and the manufacturing cost can be reduced.

  Hereinafter, the present invention will be described in detail with reference to the drawings.

  FIG. 2 shows an example of a method for producing a fiber-reinforced resin molded body of the present invention. FIG. 1 is a plan view of the same. In FIG. 2, reference numeral 1 denotes a metal lower mold that is difficult to be elastically deformed and has a rectangular hollow portion 31 having an open upper surface. The inner bottom surface 32 of the lower mold 1 is formed in a substantially flat surface and has a large curvature radius. The inner surface of the lower mold 1 is formed so that the outer surface shape of the prepreg 4 becomes a desired shape by molding described later.

  Reference numeral 2 denotes a lower upper die that is fitted into the hollow portion 31 of the lower die 1 and is made of elastic silicon resin. The bottom surface 33 is formed to have a smaller radius of curvature than the inner bottom surface 32 of the lower die. Further, the upper surface 34 of the lower upper mold 2 is formed in a plane. Reference numeral 3 denotes an upper upper mold, and a lower surface 35 thereof is formed in a plane. The upper upper mold 3 is made of silicon resin and has elasticity, and presses the lower upper mold 2. A cowl plate 5 is made of FRP. The bottom portion 36 is formed to have a smaller radius of curvature than the lower surface 33 of the lower upper mold 2 and an average angle θ between the outer surface and the vertical surface is about 10 degrees. The cowl plate 5 has a shape of the inner surface of the prepreg 4 that becomes a desired shape when the radius of curvature of the bottom portion 36 becomes large and the average angle θ becomes about 0 degrees in the molding process described later. Is formed. In this state, first, the prepreg 4 is laid along the inner bottom surface 32 of the lower mold 1 (step D).

  FIG. 3 shows a state in which the upper upper mold 3 is pressed in the direction of the lower mold 1 and the upper upper mold 3 and the lower upper mold 2 are inserted into the hollow portion 31 of the lower mold 1. Further, the lower mold 1, the lower upper mold 2, the upper upper mold 3, the cowl plate 5 and the prepreg 4 are covered with a bag 11 and a ground sheet 12 and sealed with a sealing material 13. By sucking air through the air suction port 14 from the formed sealed space, the sealed space is decompressed. As a result, the atmospheric pressure presses the bag 11, and the upper upper mold 3 presses the lower upper mold 2 with the pressing force from the bag 11, the lower upper mold 2 presses the cowl plate 5, and the cowl plate 5 is prepreg. 4 are pressed, and these move in the direction of the lower mold 1. As a result, the prepreg 4 is in linear contact with the inner bottom surface 32 of the lower mold 1 at X. Θ is about 10 degrees (initial stage of step E). Other reference numerals in FIG. 3 are the same as those in FIG.

  FIG. 4 shows a state where air is further sucked through the air suction port 14 from the sealed space formed by the bag 11, the ground sheet 12, and the sealing material 13, and the sealed space is further decompressed. As a result, the upper upper mold 3, the lower upper mold 2, and the cowl plate 5 are further moved in the direction of the lower mold 1 by the pressing force from the bag 11, and the prepreg 4 is pressed against the inner bottom surface 32 of the lower mold 1. To do. The prepreg 4 is molded following the inner bottom surface 32 of the lower mold 1. That is, the prepreg 4 is formed so that the contact portion with the lower mold inner bottom surface 32 is sequentially expanded from the linear portion X to one corner Y1 in the lower mold and the other corner Y2. As a result, the air existing between the lower mold inner bottom surface 32 and the cowl plate 5 is sequentially discharged, and no gap is generated between the prepreg 4 and the lower mold inner bottom surface 32. Further, the bottom surface of the prepreg 4 is formed smoothly without undulations. During this time, the bottom 33 of the lower upper mold is deformed so that its radius of curvature gradually increases. The cowl plate 5 is also deformed so that the radius of curvature of the bottom portion 36 is increased, and the average angle θ between the outer surface and the vertical surface is decreased (about 5 degrees) (step E). Middle stage).

  FIG. 5 shows a state where the sealed space by the bag 11, the ground sheet 12, and the sealing material 13 is further depressurized. As a result, the upper upper die 3 and the lower upper die 2 are further moved in the lower die 1 direction by the pressing force from the bag 11, and the thickness in the lower die 1 direction is reduced. It is deformed so as to increase the width in the direction orthogonal to the above. In addition, the bottom 33 of the lower upper mold has a larger radius of curvature and is substantially equal to the radius of curvature of the lower inner surface 32 of the lower mold. The cowl plate 5 moves in the direction of the lower mold 1, the curvature radius of the bottom portion 36 is further increased to be substantially equal to the curvature radius of the lower mold inner bottom surface 32, and the average angle θ between the outer surface and the vertical surface is formed. Is deformed to be almost 0 degrees. The prepreg 4 receives a pressing force due to the movement and deformation of the cowl plate 5, and the outer surface thereof is made to follow the inner surface of the lower die 1 including the side portion Z1 of the lower die 1 and the other side portion Z2. It is formed into a shape. As a result, no gap is generated between the prepreg 4 and the lower mold inner surface. Further, the outer surface of the prepreg 4 is smooth with no undulations. Further, the prepreg 4 is formed into a desired shape with its inner surface following the outer surface of the cowl plate 5. As a result, no gap is generated between the prepreg 4 and the cowl plate 5. Further, the inner surface of the prepreg 4 is smooth with no undulations. (The final stage of process E).

  Although not shown, the prepreg 4 that has undergone the final stage of the process E is further subjected to a process of heating and curing the prepreg (process F) to obtain a fiber-reinforced resin molded body.

  Although an example of the present invention has been described as described above, the present invention is not limited thereto, and the present invention can be as follows.

  In the present invention, the lower upper mold 2 and the upper upper mold 3 are elastically deformed by the pressing force applied from the bag. In the above description, silicon resin is used, but other flexible materials are used. It may be. Further, as shown in FIG. 6, a relatively thin airtight cover 15 is formed around the upper edge of the upper upper mold 3 so that the space between the lower mold 1 and the upper upper mold 3 can be sealed. It can also function as. In this case, the bag 11 and the ground sheet 12 are unnecessary.

  In the above example, the upper mold is described using two divided molds, but the number of divisions of the divided mold is arbitrary, and the upper mold without division may be used.

  The cowl plate in the present invention is preferably made of a flexible material that is less elastically deformed than the lower upper mold 2 and the upper upper mold 3. In the above description, the cowl plate made of FRP is used, but it may be made of a metal that is thin enough to be elastically deformed.

  Further, in the above description, the bottom of the prepreg 4 and the bottom surface of the lower mold are in linear contact with each other in the initial stage of manufacturing the fiber reinforced resin molded product, but the cone shape and the pyramid shape projecting downward from the upper mold bottom surface. It may be formed in a point contact.

  As the prepreg 4, a known prepreg can be used without limitation, and a prepreg laminated from 1 ply to several tens of plies can be used. The pressure applied to the prepreg is preferably 0.05 to 7 MPa. The heating temperature for heat-curing the prepreg is preferably about 90 to 180 ° C., and the heating time is about 120 to 480 minutes. These are ranges known to those skilled in the art.

  In the above description, a cowl plate is used. However, in the method for manufacturing a fiber-reinforced resin molded body of the present invention, the cowl plate can be omitted. Hereinafter, this case will be described with reference to the drawings.

  FIG. 8 shows another example of the method for producing a fiber-reinforced resin molded body of the present invention. FIG. 7 is a plan view of the same. In FIG. 8, reference numeral 51 denotes a metal lower mold which is difficult to be elastically deformed and has a rectangular hollow portion 81 whose upper surface is opened. The inner bottom surface 82 of the lower mold 51 is formed in a substantially flat surface and has a large curvature radius. The inner surface of the lower mold 51 is formed so that the outer surface shape of the prepreg 54 becomes a desired shape by molding described later.

  An upper die 52 is fitted into the hollow portion 81 of the lower die 51 and is made of elastic silicon resin. A bottom surface 83 of the lower die 83 has a smaller radius of curvature than the inner bottom surface 82 of the lower die. The upper mold 52 is formed such that an average angle δ formed between the outer surface and the vertical surface is about 10 degrees. The upper die 52 has a shape in which the inner surface of the prepreg 54 has a desired shape when the radius of curvature of the bottom 83 becomes large and the average angle δ becomes about 0 degrees in the molding process described later. Is formed. In this state, first, the prepreg 54 is laid along the inner bottom surface 82 of the lower mold 51 (step A).

  FIG. 9 shows a state in which the upper die 52 is pressed in the direction of the lower die 51 and the upper die 52 is inserted into the hollow portion 81 of the lower die 51. Further, the lower mold 51, the upper mold 52 and the prepreg 54 are covered with a bag 61 and a ground sheet 62 and sealed with a sealing material 63. Air is sucked through the air suction port 64 from the formed sealed space, and the sealed space is decompressed. As a result, the upper mold 52 presses the prepreg 54 with the pressing force from the bag 61, and each moves in the direction of the lower mold 51. As a result, the prepreg 54 moves so as to be in linear contact with the inner bottom surface 82 of the lower mold 51 at the X. Note that δ is about 10 degrees (the initial stage of the process B). Other reference numerals in FIG. 9 are the same as those in FIG.

  FIG. 10 shows a state where air is further sucked through the air suction port 64 from the sealed space formed by the bag 61, the ground sheet 62, and the sealing material 63, and the sealed space is further decompressed. As a result, the upper mold 52 moves in the direction of the lower mold 51 while being deformed by the pressing force from the bag 61, and presses the prepreg 54 against the inner bottom surface 82 of the lower mold 51. The prepreg 54 is molded following the inner bottom surface 82 of the lower mold 51. That is, the prepreg 54 is molded so that the contact portion with the lower mold inner bottom surface 82 is sequentially enlarged from the linear part X to both corners Y1 and Y2 in the lower mold 51. As a result, no gap is generated between the prepreg 54 and the lower mold inner bottom surface 82. During this time, the bottom 83 of the upper mold is deformed so that the radius of curvature gradually increases, and the average angle δ between the outer surface and the vertical surface is decreased (about 5 degrees) (step). B middle stage).

  FIG. 11 shows a state where the sealed space is further depressurized. As a result, the upper mold 52 is further moved in the direction of the lower mold 51 by the pressing force from the bag 61, the thickness in the direction of the lower mold 51 is reduced, and the width is expanded in the lateral direction (a direction orthogonal to the direction of the lower mold 1). It is deformed to do. In addition, the curvature radius of the bottom 83 of the upper mold is further increased to be substantially equal to the curvature radius of the inner bottom surface 82 of the lower mold, and the average angle θ between the outer surface and the vertical surface is almost 0 degrees. It is deformed like this. The prepreg 54 receives a pressing force due to the movement and deformation of the upper mold 52 and is formed into a desired shape with its outer surface imitating the inner surface of the side of the lower mold 51, and its inner surface is imitated to the outer surface of the upper mold 52. And formed into a desired shape. As a result, there is no gap between the prepreg 54 and the lower mold inner surface and the upper mold 52 outer surface. Further, the outer surface and the inner surface of the prepreg 54 are smooth with no undulations (the final stage of the process B).

  The prepreg 54 that has undergone the process B is further subjected to a process of heating and curing the prepreg (process C).

It is a front view which shows an example of the molded article obtained by the manufacturing method of this invention. It is a figure which shows an example of sectional drawing in the process D of this invention. It is a figure which shows an example of sectional drawing in the initial stage of the process E of this invention. It is a figure which shows an example of sectional drawing in the intermediate stage of the process E of this invention. It is a figure which shows an example of sectional drawing in the final stage of the process E of this invention. It is sectional drawing which shows an example at the time of using an upper mold | type as a reusable bag in this invention. It is a front view which shows another example of the molded article obtained by the manufacturing method of this invention. It is a figure which shows an example of sectional drawing in the process A of this invention. It is a figure which shows an example of sectional drawing in the initial stage of the process B of this invention. It is a figure which shows an example of sectional drawing in the middle stage of the process B of this invention. It is a figure which shows an example of sectional drawing in the final stage of the process B of this invention.

Explanation of symbols

1, 51 Lower mold 2 Lower upper mold 3 Upper upper mold 52 Upper mold 4, 54 Prepreg 5 Cowl plate 11, 61 Bag 12, 62 Ground sheet 13, 63 Sealing material 14, 64 Air suction port 15 Airtight cover section 31, 81 Lower mold hollow portion 32, 82 Lower mold inner bottom surface 33 Lower upper mold bottom surface 83 Upper mold bottom surface 34 Upper upper mold upper surface 35 Lower upper mold bottom surface 36 Cowl plate bottom surface X Lower side of prepreg and lower mold inner bottom surface Y1 One corner in the lower die Y2 The other corner in the lower die Z1 One side in the lower die Z2 The other side in the lower die θ The outer surface of the cowl plate Angle between the upper surface and the vertical surface δ Average angle between the outer surface of the upper mold and the vertical surface

Claims (3)

A prepreg is inserted between a lower mold and an upper mold having flexibility that is inserted into the lower mold and whose bottom surface is formed with a radius of curvature smaller than that of the inner bottom surface of the lower mold. Step (A), and then pressing the upper die in the lower die direction, pressing the prepreg along one point or line, forming the upper die while following the lower die while deforming the upper die and the lower die The manufacturing method of the fiber reinforced resin molding which has the process (B) which makes a pressure reduction between, and the process (C) which heats after that and hardens a prepreg. Between the lower mold and the upper mold having a flexibility inserted into the lower mold, the bottom of which is formed with a radius of curvature smaller than the radius of curvature of the inner bottom of the lower mold, the upper mold A step (D) of inserting a flexible cowl plate having a smaller radius of curvature than the mold bottom, and further inserting a prepreg below the cowl plate, and then pressing the upper mold in the direction of the lower mold along one point or line A step (E) of pressing and molding the lower plate while deforming the cowl plate and reducing the pressure between the upper die and the lower die, and then a step (F) of heating and curing the prepreg. The manufacturing method of the fiber reinforced resin molding which has. The manufacturing method of the fiber reinforced resin molding of Claim 1 or 2 in which a fiber reinforced resin molding has a three-dimensional structure.

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