JP2018138355A - Fiber-reinforced plastic molded article, and molding method thereof - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a fiber-reinforced plastic molded article exhibiting high interfacial strength between a sheet surface and a projection member formed on the surface, and to provide a molding method thereof.SOLUTION: There is provided a fiber-reinforced plastic molded article in which a projection member 5 is formed on a surface of a thermoplastic resin sheet 1 having oriented continuous fibers therein. The fiber-reinforced plastic molded article comprises a swelling part 2 and a through-hole 3 that are formed so as to protrude from one surface side to the other surface side in the resin sheet 1. The projection member 5 is connected to a region including the swelling part 2 and the through-hole 3. When injection-molding the projection member 5, an injected resin is charged into an internal cavity 2a of the swelling part 2 via the through-hole 3 formed at the swelling part 2, and thus a resin forming the projection member 5 and the resin that goes around into the swelling part 2 are integrated. Therefore, bonding strength between the projection member 5 and the resin sheet 1 in the fiber-reinforced plastic molded article becomes remarkably high.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a fiber-reinforced plastic molded article and a molding method thereof. More specifically, the present invention relates to a fiber reinforced plastic molded article in which a protruding member is formed on the surface of a thermoplastic resin sheet reinforced with continuous fibers, and a molding method thereof.

A thermoplastic resin sheet reinforced with continuous fibers has high strength but is difficult to be molded into a complicated shape. Therefore, once formed into a simple shaped sheet by clamping such as press molding or injection molding, a continuous fiber reinforced thermoplastic resin having a complicated shape is formed by providing protrusions such as ribs on the surface of the sheet by injection molding or the like. A molded product is obtained (Patent Document 1).
However, in this molding method, since the protruding portion is formed by injection molding on the flat portion of the sheet, there is a problem that the area of the interface that is a joint surface between the sheet portion and the protruding portion is reduced, and the interface strength is low. is there.

As a method for increasing the interface strength, there are the following conventional techniques.
In Patent Document 2, an attempt is made to increase the bonding strength between resin pieces by compressing a sheet surface with a press die to give an uneven shape and exposing continuous fibers in a concave or convex shape by cutting. Yes.
In Patent Document 3, the contact surfaces of two resin pieces are faced with inclined surfaces inclined at different angles, and injection molding is performed to improve the flow of resin and increase the adhesive strength.

  However, the conventional techniques of Patent Documents 2 and 3 have a problem that the degree of increase in the contact area at the interface is small and the interface strength cannot be significantly improved.

JP 2014-148124 A JP 2014-136357 A JP 2013-6389 A

  SUMMARY OF THE INVENTION In view of the above circumstances, an object of the present invention is to provide a fiber-reinforced plastic molded article having a high interface strength between a thermoplastic resin sheet surface reinforced with continuous fibers and a protruding member formed on the surface, and a molding method thereof. And

The fiber-reinforced plastic molded article of the first invention is a fiber-reinforced plastic molded article in which a protruding member is provided on the surface of a thermoplastic resin sheet oriented with continuous fibers, from one surface to the other of the thermoplastic resin sheet. A bulging portion formed so as to protrude to the front surface side, a through hole formed in the thermoplastic resin sheet, and a region where the protruding member of the thermoplastic resin sheet includes the bulging portion and the through hole. It is connected.
The fiber-reinforced plastic molded product of the second invention is characterized in that, in the first invention, the through hole is formed in the bulging portion.
The fiber-reinforced plastic molded product of the third invention is characterized in that, in the first invention, the through hole is formed in a region other than the bulging portion.
In the fiber-reinforced plastic molded product according to a fourth aspect of the present invention, in the second or third aspect of the invention, the bulging portion is formed such that the inner cavity has an inner diameter that increases from the top side to the back side of the bulging portion. It is characterized by.
A molding method of a fiber reinforced plastic molded product according to a fifth aspect of the present invention is a molding method of a fiber reinforced plastic molded product in which a protruding member is molded by injection molding on the surface of a thermoplastic resin sheet in which continuous fibers are oriented. A step of pressing a pressing member from one surface of the resin sheet to form a bulging portion on the other surface, a step of forming a through-hole in the thermoplastic resin sheet, and the step formed in the thermoplastic resin sheet And forming the projecting member by injection molding in a region including the bulging portion and the through hole.
According to a sixth aspect of the present invention, there is provided a molding method for a fiber-reinforced plastic molded product according to the fifth aspect of the present invention, wherein in the step of forming the bulging portion and the through hole, the bulging portion and the through hole are formed in the same step by the pressing member. It is characterized by forming.
According to a seventh aspect of the present invention, in the method of forming a fiber-reinforced plastic molded article, in the fifth aspect, in the step of forming the bulging portion and the through hole, the bulging portion and the through hole are formed in separate steps. Features.

According to the first invention, since the resin is filled through the through hole in the internal cavity of the bulging portion formed in the thermoplastic resin sheet and the protruding member, the resin forming the protruding member and the bulging portion The wraparound resin is integrated. Therefore, the bond strength between the protruding member of the fiber reinforced plastic molded product and the thermoplastic resin sheet is dramatically increased.
According to the second aspect of the invention, since the resin in the bulging portion is filled with the resin through the through hole formed in the bulging portion, the resin that forms the protruding member and the resin that has entered the bulging portion are integrated. In addition, the bond strength between the protruding member of the fiber-reinforced plastic molded product and the thermoplastic resin sheet has been dramatically increased.
According to the third invention, since the resin is filled in the internal cavity of the bulging portion through the through hole formed in the portion other than the bulging portion, the resin forming the protruding member and the resin entering the bulging portion are Are integrated, and the bond strength between the protruding member of the fiber-reinforced plastic molded product and the thermoplastic resin sheet is dramatically increased.
According to the fourth aspect of the invention, the internal space of the bulging portion expands from the top side toward the back surface side, so that the resin filled in the internal cavity of the bulging portion has a shape that expands toward the back surface side. Since the resin shape becomes a resistance to the drawing direction of the protruding member, the bonding strength of the protruding member to the thermoplastic resin sheet is further increased.
According to the fifth invention, when the protruding member is injection-molded, the injected resin wraps around the internal cavity of the bulging portion through the through hole, and wraps around the resin forming the protruding member and the bulging portion. Integrate with resin. Therefore, the bond strength between the protruding member of the fiber-reinforced plastic molded product and the thermoplastic resin sheet can be dramatically increased.
According to the sixth invention, when the bulging portion and the through hole are formed in the same process, the fiber-reinforced plastic molded product can be molded with a small number of processes.
According to the seventh invention, if the bulging portion and the through hole are formed in separate steps, the bulging portion and the through hole having an arbitrary shape can be formed, which is advantageous in increasing the coupling strength of the protruding member.

It is explanatory drawing which shows the shaping | molding method of the fiber reinforced plastics molded product which concerns on 1st Embodiment of this invention. (A) is a detailed view of step II in FIG. 1, (B) is an explanatory view of a pressing member, and (C) is an explanatory view of a bulging portion and a through hole. (A) A figure is explanatory drawing of the other shape of a bulging part and a through-hole, (B) figure is explanatory drawing of a press member. (A) A figure is explanatory drawing of the further another shape of a bulging part and a through-hole, (B) figure is explanatory drawing of a press member. It is explanatory drawing of the fiber reinforced plastic molding A made with the shaping | molding method of this invention, (A) is a perspective view, (B) is a side view of the (A) figure. It is explanatory drawing of the fiber reinforced plastic molded product B made with the shaping | molding method of this invention, (A) is a perspective view, (B) is a side view of the (A) figure. It is explanatory drawing of the fiber reinforced plastic molded product C made by the shaping | molding method of this invention, (A) is explanatory drawing of the shaping | molding die 10, (B1) is sectional drawing of a molded product, (B2) is a perspective view of a molded product. FIG. It is explanatory drawing of the fiber reinforced plastic molded product D made by the shaping | molding method of this invention, (A) is explanatory drawing of the shaping | molding die 10, (B1) is sectional drawing of a molded product, (B2) is a perspective view of a molded product. FIG.

Next, an embodiment of the present invention will be described with reference to the drawings.
The object of application of the present invention is a fiber reinforced plastic molded product in which a protruding member is formed on a thermoplastic resin sheet (hereinafter referred to as a resin sheet) reinforced with continuous fibers, and the present invention provides a molded product obtained and a molding method used therefor It is.
The resin sheet uses a thermoplastic resin in which continuous fibers are oriented and reinforced, and has high strength but is difficult to press-mold in a complicated shape.

For the continuous fiber, carbon fiber, glass fiber, or the like is used as a raw material, and the fiber is oriented in one direction, the fiber is oriented in a lattice shape, or the laminate is oriented.
The shape of the resin sheet is typically a flat plate shape, but includes a resin sheet having a flat plate shape that is primarily processed to be gently curved or curved only at the edges. .

The protruding member is formed by injection molding. In addition, as long as injection molding is possible, the short resin etc. may be mix | blended with the molding resin of the protrusion member.
The shape of the protruding member can be exemplified by members such as a rod shape, a plate shape, and a block shape, but is not limited thereto.

  In the fiber reinforced plastic molded product in which the protruding member is erected on the surface of the resin sheet, the strength of the interface which is a joint surface between the protruding member and the resin sheet affects the overall strength. It is the molding method of the present invention to mold so as to increase the strength.

The molding method will be described with reference to FIG.
FIG. 1 shows the basic concept of the molding method according to the present invention.
(I) Preparatory Step The molding die 10 of the injection molding machine is composed of a fixed die 12 and a movable die 13 disposed so as to be able to advance and retreat with respect to the fixed die 12. The movable die 13 has a fixed die 12 side. A pressing member 20 that can freely move forward and backward is provided. A cavity 11 is formed between the fixed mold 12 and the movable mold 13.
In the preparation step, the resin sheet 1 is set between the fixed mold 12 and the movable mold 13. The resin sheet 1 is heated by a heating means.

(II) Swelling portion / through-hole forming step The pressing member 20 is pressed against the cavity 11 to press the resin sheet 1.
The pressing member 20 includes a cylindrical rod 21 and a pin 22 formed at the tip thereof. By pressing the pressing member 20 from one surface of the resin sheet 1 to the opposite surface, the bulging portion 2 is formed in the resin sheet 1 and the through hole 3 is formed in the bulging portion 2 by the rod 21.

(III) Retraction of the pressing member When the pressing member 20 is retracted, the bulging portion 2 is formed in the resin sheet 1, and the through hole 3 is formed at the apex of the bulging portion 2. In this state, the preparation for the next injection molding is completed.
(IV) Injection Molding Although not shown, resin is filled into the cavity 11 of the mold 10 with a filling device from the fixed mold 12 side. The filling direction may be from the cavity side (arrow x direction) or from the opposite cavity side (side with the pressing member 20). In the anti-cavity direction, a filling device and a pressing member 20 are provided on the fixed mold 13 side.

Details of the step (II) will be described with reference to FIG.
(B) is a single view of the pressing member 20, and comprises a cylindrical rod 21 and a needle-like pin 22 formed at its tip. The length of the rod 21 can be set to an arbitrary length according to the mold 10, and the diameter may be selected according to the size of the bulging portion 2 to be formed. The length and thickness of the pin 22 may be selected according to the through hole 3 to be formed.

(A) (1)-(3) of the figure has shown the detail (embodiment of 6th invention) of the bulging part and through-hole formation process (II) which forms the bulging part 2 and the through-hole 3 simultaneously. .
In (1) of the figure, the pins 22 are starting to perforate the resin sheet 1.
In (2) of the figure, the perforated portion is being enlarged while the resin sheet 1 is pushed and spread by the shoulder of the rod 21 to form the bulging portion 2.
As shown in (3) of the figure, when the rod 21 and the pin 22 penetrate the resin sheet 1 by a predetermined amount, the bulging portion 2 is formed and the formation of the through hole 3 is completed.

In the bulging portion 2 thus obtained, as shown in FIG. (C), the inside of the bulging portion 2 is a cavity, and the inner diameter of the inner cavity 2 a corresponds to the diameter of the rod 21. The length of the internal cavity 2a is determined by the amount of penetration of the rod 21.
The shape of the internal cavity 2a is formed such that the inner diameter increases from the top side of the bulging portion 2 toward the back surface side. The reason is that the pressing member 20 is pressed against the internal resistance of the resin sheet 1 that is clamped, thereby stopping the press molding in a state where tensile resistance is generated inside the sheet.
The size of the through hole 3 formed at the top of the bulging portion 2 is determined by the diameter of the pin 22, and the drilling position is determined by the position where the pin 22 is formed with respect to the rod 21.

  When the protruding member is formed on the resin sheet 1 having the bulging portion 2 and the through-hole 3 as described above, the resin r is injected into the cavity 11 of the mold 10 as shown in FIG. Fill. In this case, the resin r is filled in the cavity 11 and the internal cavity 2a of the bulging portion 2 regardless of whether the resin r is injected from either the cavity side (arrow x direction) or the opposite cavity side. This is because the cavity 11 and the inside of the bulging portion 2 communicate with each other through the through hole 3.

  Thus, when the injected resin r is filled into the internal cavity 2a of the bulging portion 2 through the through-hole 3 formed in the bulging portion 2, the resin r and the bulging portion forming the protruding member The resin r that wraps around in 2 is integrated. Therefore, the area of the interface that defines the bonding strength between the protruding member of the plastic molded product and the resin sheet 1 is dramatically increased. This is the technical principle that characterizes the present invention.

The formation position and shape of the through-hole 3 are not limited to those shown in FIG. In short, what is necessary is just to make the cavity 11 in the shaping | molding die 10 and the internal cavity 2a of the bulging part 2 connect.
Therefore, as shown in FIG. 3A, the through-hole 3 may be formed not on the apex of the bulging portion 2 but on the side portion. In the illustrated example, the number of through holes 3 formed is two, but may be three or more.

  As the pressing member 20 for forming the through holes 3 and 3 in the side portion of the bulging portion 2, the bulging portion is formed with two or more sharp pins 22 for forming the through holes on the front end surface of the rod 21. For example, the pressing member 20 provided with the flat head type pin 23 can be illustrated.

Still another example will be described with reference to FIG.
The example shown in FIG. 4 (A) is an example in which the through hole 3 is formed on the side slightly away from the base of the bulging portion 2. In this case, if the passage 14 of the resin r is formed in the mold 10, the cavity 11 and the inside of the bulging portion 2 can be communicated with each other.

  As the pressing member 20 for forming the side through-holes 3 and 3 as described above, a flat head type pin 23 for forming a bulging part at the center of the front end of the rod 21 having a large diameter, and a little from the pin 23 For example, one having two or more sharp pins 22 for forming through-holes on the laterally separated sides can be exemplified.

In the embodiment shown in FIGS. 1 and 2, the bulging portion 2 and the through hole 3 are formed simultaneously in the same process. Thus, if the bulging part 2 and the through-hole 3 are formed in the same process, it can shape | mold with few processes and can shorten shaping | molding time.
However, unlike the above, the bulging portion 2 and the through hole 3 may be formed in separate steps.
When the bulging portion 2 and the through hole 3 are formed in separate steps (the seventh embodiment), the rod 21 of the pressing member 20 is first penetrated to form the bulging portion 2 first, and then the pin The through hole 3 may be formed by penetrating 22, the through hole 3 may be formed first by penetrating the pin 22 first, and then the bulging portion 2 may be formed by penetrating the rod 21. .

  As the pressing member 20 used in the separate process method as described above, a structure in which the pin 22 is configured to be nested with respect to the rod 21 and the rod 21 and the pin 22 are individually operated can be exemplified. Alternatively, separate rods 21 and pins 22 may be used, and after one (rod or pin) has penetrated, the other (pin or rod) may penetrate.

  In addition to the above, the formation method of the bulging part 2 and the through-hole 3 may be arbitrarily adopted. If such another process method is used, it can be formed in the bulging portion 2 or the through hole 3 having an arbitrary shape, which is advantageous in increasing the coupling strength of the protruding member.

Next, a fiber reinforced plastic molded product (hereinafter referred to as a plastic molded product) obtained by the above molding method will be described.
A plastic molded product A in FIG. 5A is obtained by forming a resin sheet 1 and a rod-like protruding member 5 on the surface thereof. The resin sheet 1 is a sheet using a thermoplastic resin in which continuous fibers are oriented as described above. The protruding member 5 is formed by injecting the resin r as described above.

  As shown in FIG. 5B, the protruding member 5 has a shape standing on the surface of the resin sheet 1, but the resin r forming the protruding member 5 is inside the bulging portion 2 formed on the sheet 1. The cavity 2a is also filled. As a result, the area of the interface where the resin r comes into contact with the protruding member 5 and the resin sheet 1 is widened, and the bonding strength becomes very high.

  Moreover, when the inner cavity 2a of the bulging portion 2 has an inner diameter that widens from the top side toward the back surface side, the resin r filled inside the bulging portion 2 has a shape that expands toward the back surface side. The resin shape becomes a resistance to the pulling direction of the protruding member 5. For this reason, the bonding strength of the protruding member 5 to the resin sheet 1 is further increased.

  In the plastic molded product B of FIG. 6A, the protruding member 6 has a thick plate shape. Although the number of the bulging portions 2 with the through holes 3 shown in the figure is three, the number is not limited to this, and an appropriate number may be formed in accordance with the longitudinal dimension of the protruding member 6.

The protruding member is not limited to a rod shape as shown in FIG. 5A, but can be formed in a thick plate shape shown in FIG. 6A and used in the form of a rib.
Furthermore, not only a rod shape or a thick plate shape, but any shape of protruding member can be formed on the resin sheet 1 as long as injection molding is possible.

The resin sheet 1 shown in FIGS. 5 and 6 has a flat plate shape, but the resin sheet 1 is not limited to this and may be somewhat curved.
FIG. 7A shows that the facing surfaces of the fixed mold 12 for molding the resin sheet 1 and the movable mold 13 are gently curved. When this mold 10 is used, a plastic molded product C in which the protruding member 5 is formed on the resin sheet 1 curved in a shallow dish shape is obtained, as shown in FIGS.

  FIG. 8A shows a case where the facing surfaces of the fixed mold 12 and the movable mold 13 are curved in a deep dish shape. When such a mold 10 is used, a plastic molded product D in which a protruding member 5 is formed on a resin sheet 1 curved in a deep dish shape is obtained, as shown in the same figure (B1, B2).

Although FIG. 7 shows the shallow dish-shaped resin sheet 1 formed with the rod-shaped projecting member 5, the thick plate-shaped projecting member 6 may be formed. Although FIG. 8 shows a deep dish-shaped resin sheet 1 formed with a thick plate-like protruding member 6, a rod-shaped protruding member may be formed.
Further, the resin sheet 1 may be formed in a curved or deep dish shape by clamping the fixed mold 12 and the movable mold 13, and may be curved or deep dished by another processing means before being inserted into the molding die 10. You may form in a shape.
Thus, the combination of the resin sheet 1 and the protruding member 5 is arbitrary, and there is no particular limitation.

DESCRIPTION OF SYMBOLS 1 Resin sheet 2 Bulging part 2a Internal cavity 3 Through-holes 5, 6 Protruding member 10 Mold 11 Cavity 20 Pressing member 21 Rod 22 Pin

Claims (7)

A fiber reinforced plastic molded article provided with a protruding member on the surface of a thermoplastic resin sheet oriented continuous fibers,
A bulging portion formed so as to protrude from one surface of the thermoplastic resin sheet to the other surface side;
A through hole formed in the thermoplastic resin sheet;
The protruding member of the thermoplastic resin sheet is connected to a region including the bulging portion and the through hole.
A fiber-reinforced plastic molded product characterized by that. 2. The fiber-reinforced plastic molded product according to claim 1, wherein the through hole is formed in the bulging portion. 2. The fiber-reinforced plastic molded product according to claim 1, wherein the through hole is formed in a region other than the bulging portion. 4. The fiber-reinforced plastic molded product according to claim 2, wherein the bulging portion is formed such that an inner diameter of an inner cavity of the bulging portion increases from a top side to a back side of the bulging portion. A method of molding a fiber reinforced plastic molded product in which a protruding member is molded by injection molding on the surface of a thermoplastic resin sheet in which continuous fibers are oriented,
A step of pressing with a pressing member from one surface of the thermoplastic resin sheet to form a bulging portion on the other surface;
Forming a through hole in the thermoplastic resin sheet;
A step of forming the protruding member by injection molding in a region including the bulging portion and the through-hole formed in the thermoplastic resin sheet.
A method for molding a fiber-reinforced plastic molded product. 6. The molding of a fiber-reinforced plastic molded product according to claim 5, wherein in the step of forming the bulging portion and the through hole, the bulging portion and the through hole are formed by the pressing member in the same step. Method. 6. The method for forming a fiber-reinforced plastic molded product according to claim 5, wherein in the step of forming the bulging portion and the through hole, the bulging portion and the through hole are formed in separate steps.

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