JP6906838B2 - Fiber reinforced plastic molded product and its molding method - Google Patents

Description

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

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

As a method for increasing the interfacial 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 the sheet surface with a press die to give an uneven shape and exposing continuous fibers in a concave or convex form by cutting. There is.
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, in the prior arts of Patent Documents 2 and 3, there is a problem that the degree of increase in the contact area at the interface is small and the interface strength cannot be significantly improved.

Japanese Unexamined Patent Publication No. 2014-148124 Japanese Unexamined Patent Publication No. 2014-136357 Japanese Unexamined Patent Publication No. 2013-6389

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

The fiber-reinforced plastic molded product of the first invention is a fiber-reinforced plastic molded product in which a protruding member formed of resin is provided on the surface of a thermoplastic resin sheet in which continuous fibers are oriented, and the thermoplastic resin sheet is used. A bulge formed so as to be pushed from one surface to the other surface and a through hole formed around the bulge or the bulge, and the internal cavity of the bulge is the bulge. The inner diameter is formed so as to expand from the top side of the protruding portion toward the back surface side, and the protruding member of the thermoplastic resin sheet is made of a resin formed on the outside of the bulging portion, and the bulging portion is formed. It is characterized in that it is integrated with the internal space of the above and the resin filled in the inside of the through hole.
The fiber-reinforced plastic molded product of the second invention is characterized in that, in the first invention, the through hole is formed at the top or side of the bulge.
The fiber-reinforced plastic molded product of the third invention is characterized in that, in the first invention, the through hole is formed laterally away from the root of the bulging portion .
The method for molding a fiber-reinforced plastic molded product of the fourth invention is a method for 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, and the thermoplasticity is described. A step of forming a bulging portion on the other surface by pressing from one surface of the resin sheet with a pressing member, a step of forming a through hole in the thermoplastic resin sheet, and the step of forming a through hole in the thermoplastic resin sheet. It is characterized by comprising a step of molding the protruding member by injection molding in a region including a bulging portion and the through hole.
In the fourth invention, the method for molding a fiber-reinforced plastic molded product of the fifth invention is the same step of forming the bulge and the through hole with the pressing member in the step of forming the bulge and the through hole. It is characterized by forming.
In the fourth invention, the method for molding a fiber-reinforced plastic molded product of the sixth invention is to form the bulge and the through hole in separate steps in the step of forming the bulge and the through hole. It is a feature.

According to the first invention, since the resin is filled in the internal cavity of the bulge formed in the thermoplastic resin sheet and the protruding member through the through hole, the resin forming the protruding member and the bulging portion are filled with the resin. The wraparound resin is integrated. Moreover, since the inner cavity of the bulging portion has an inner diameter that expands from the top side to the back surface side, the resin filled inside the bulging portion also has a shape that expands toward the back surface side, and this resin shape protrudes. It becomes a resistance force in the pulling direction of the member. Therefore, the bonding strength between the protruding member of the fiber-reinforced plastic molded product and the thermoplastic resin sheet is dramatically increased.
According to the second invention, since the resin is filled in the internal cavity of the bulging portion through the through hole formed in the bulging portion, the resin forming the protruding member and the resin entering the bulging portion are integrated. Therefore, the bonding strength between the protruding member of the fiber reinforced plastic molded product and the thermoplastic resin sheet is dramatically increased.
According to the third invention, since the resin is filled in the internal cavity of the bulging portion through the through hole on the side of the bulging portion, the resin forming the protruding member and the resin entering the bulging portion are integrated. Therefore, the bonding strength between the protruding member of the fiber reinforced plastic molded product and the thermoplastic resin sheet is dramatically increased .
According to the fourth invention, when the projecting member was 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 projecting member and the bulging portion. Integrate with resin. Therefore, the bonding strength between the protruding member of the fiber reinforced plastic molded product and the thermoplastic resin sheet can be dramatically increased.
According to the fifth invention, if the bulging portion and the through hole are formed in the same step, the fiber reinforced plastic molded product can be molded in a small number of steps.
According to the sixth invention, if the bulging portion and the through hole are formed in separate steps, the bulging portion and the through hole can be formed into an arbitrary shape, which is advantageous for increasing the bonding strength of the protruding member.

It is explanatory drawing which shows the molding method of the fiber reinforced plastic molded article which concerns on 1st Embodiment of this invention. (A) is a detailed view of step II of 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) is an explanatory view of other shapes of the bulging portion and the through hole, and (B) is an explanatory view of the pressing member. (A) is an explanatory view of still another shape of the bulging portion and the through hole, and (B) is an explanatory view of the pressing member. It is explanatory drawing of the fiber reinforced plastic molded article A made by the molding method of this invention, (A) is a perspective view, (B) is a side view of the figure (A). It is explanatory drawing of the fiber reinforced plastic molded article B made by the molding method of this invention, (A) is the perspective view, (B) is the side view of the figure (A). It is explanatory drawing of the fiber reinforced plastic molded article C made by the molding method of this invention, (A) is the explanatory view of the molding die 10, (B1) is the sectional view of the molded article, (B2) is the perspective view of the molded article. It is a figure. It is explanatory drawing of the fiber reinforced plastic molded article D made by the molding method of this invention, (A) is the explanatory view of the molding die 10, (B1) is the sectional view of the molded article, (B2) is the perspective view of the molded article. It is a figure.

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. Is.
The resin sheet uses a thermoplastic resin in which continuous fibers are oriented and reinforced, and it is difficult to press-mold a high-strength but complicated shape.

As the continuous fiber, carbon fiber, glass fiber, or the like is used as a material, and one in which the fibers are oriented in one direction, one in which the fibers are oriented in a lattice pattern, or one in which the fibers are laminated and oriented is used.
The shape of the resin sheet is typically a flat plate, but the shape of the flat resin sheet is primarily processed to be gently curved as a whole, or only the edge is curved. ..

The protruding member is molded by injection molding. As long as injection molding is possible, short fibers or the like may be blended in the molding resin of the protruding member.
The shape of the projecting member can be exemplified by a rod-shaped, plate-shaped, block-shaped member, etc., but is not limited thereto.

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

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

(II) Molding step of bulging portion / through hole The pressing member 20 is pressed against the cavity 11 side 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 side to the other side of the resin sheet 1, the rod 21 forms a bulging portion 2 in the resin sheet 1 and a through hole 3 in the bulging portion 2.

(III) Retracting 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 injection molding in the next step is completed.
(IV) Injection Molding Although not shown, the cavity 11 of the molding die 10 is filled with resin by a filling device from the fixed mold 12 side. The filling direction may be from the cavity side (arrow x direction) or from the anti-cavity side (the side where the pressing member 20 is located). In the anti-cavity direction, a filling device and a pressing member 20 are provided on the fixed mold 13 side.

The details of the step (II) will be described with reference to FIG.
The figure (B) is a single figure of the pressing member 20, and is composed of a columnar rod 21 and a needle-shaped pin 22 formed at the tip thereof. The length of the rod 21 can be set to an arbitrary length according to the molding die 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 also be selected according to the through hole 3 to be formed.

(A) (1) to (3) in the figure show the details (the embodiment of the sixth invention) of the bulging part / through hole forming step (II) which forms the bulging part 2 and the through hole 3 at the same time. ..
In (1) of the figure, the pin 22 has begun to perforate the resin sheet 1.
In (2) of the figure, the resin sheet 1 is pushed open by the shoulder of the rod 21 to form the bulging portion 2, and the perforated portion is also being enlarged.
As shown in (3) of the figure, when the rod 21 and the pin 22 penetrate into the resin sheet 1 by a predetermined amount, the bulging portion 2 is formed and the formation of the through hole 3 is completed.

As shown in FIG. 3C, the bulging portion 2 thus completed has a hollow inside of the bulging portion 2, and the inner diameter of the internal cavity 2a corresponds to the diameter of the rod 21. The length of the internal cavity 2a is determined by the penetration amount of the rod 21.
The shape of the internal cavity 2a is formed so 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 presses against the internal resistance of the mold-fastened resin sheet 1 to stop the pressing 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 thereof is determined by the forming position of the pin 22 with respect to the rod 21.

When the projecting member is formed on the resin sheet 1 having the bulging portion 2 and the through hole 3 formed as described above, the resin r is injected into the cavity 11 of the molding die 10 as shown in FIG. 1 (IV). Fill. In this case, regardless of whether the resin r is injected from the cavity side (arrow x direction) or the anti-cavity side, the resin r is filled in the cavity 11 and in the internal cavity 2a of the bulging portion 2. The reason is that the cavity 11 and the inside of the bulging portion 2 communicate with each other through the through hole 3.

When the injected resin r is filled in 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 are formed. 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 is characteristic of the present invention.

The formation position and shape of the through hole 3 are not limited to those shown in FIG. In short, the cavity 11 in the molding die 10 and the internal cavity 2a of the bulging portion 2 may be communicated with each other.
Therefore, as shown in FIG. 3A, the through hole 3 may be formed not at the apex of the bulging portion 2 but at the side portion. In the illustrated example, the number of through holes 3 formed is two, but it may be three or more.

As the pressing member 20 for forming the through holes 3 and 3 on the side portion of the bulging portion 2, two or more sharp pins 22 for forming the through hole are formed on the front end surface of the rod 21 and the bulging portion is formed. A pressing member 20 provided with a flat-headed pin 23 for use can be exemplified.

Yet another example will be described with reference to FIG.
The example shown in FIG. 4A is an example in which the through hole 3 is formed on the side slightly separated from the root of the bulging portion 2. In this case, if the path 14 of the resin r is formed in the molding die 10, the cavity 11 and the inside of the bulging portion 2 can be communicated with each other.

The pressing member 20 for forming the side through holes 3 and 3 as described above includes a flat-headed pin 23 for forming a bulge in the center of the front end of the rod 21 having a large diameter, and a little from the pin 23. Examples thereof include those provided with two or more sharp pins 22 for forming through holes on the laterally separated sides.

In the embodiment of FIGS. 1 and 2, the bulging portion 2 and the through hole 3 are formed at the same time in the same process. If the bulging portion 2 and the through hole 3 are formed in the same process in this way, molding can be performed in a small number of steps, and the molding time can be shortened.
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 embodiment of the seventh invention), the rod 21 of the pressing member 20 is penetrated first to form the bulging portion 2 first, and then the pin is formed. 22 may be penetrated to form the through hole 3, or the pin 22 may be penetrated first to form the through hole 3, and then the rod 21 may be penetrated to form the bulging portion 2. ..

As the pressing member 20 used in the above-mentioned separate process method, a structure in which the pin 22 is nested with respect to the rod 21 and the rod 21 and the pin 22 are operated individually can be exemplified. Alternatively, a separate rod 21 and pin 22 may be used, and after the penetration of one (rod or pin), the rod or pin 22 may be completely retracted and the other (pin or rod) may be penetrated.

In addition to the above, the method of forming the bulging portion 2 and the through hole 3 may be arbitrarily adopted. When such a separate 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 bonding 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.
The plastic molded product A of FIG. 5A is a resin sheet 1 having a rod-shaped protruding member 5 formed on its surface. The resin sheet 1 is a sheet using a thermoplastic resin in which continuous fibers are oriented as described above. The projecting member 5 is formed by injecting the resin r as described above.

As shown in FIG. 5B, the protruding member 5 has a shape erected 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 projecting 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 expands from the top side toward the back surface side, the resin r filled inside the bulging portion 2 expands toward the back surface side. The resin shape provides resistance to the pulling direction of the protruding member 5. Therefore, the bonding strength of the projecting member 5 to the resin sheet 1 becomes even stronger.

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

The projecting member is not limited to the rod shape as shown in FIG. 5 (A), but may be formed in the thick plate shape shown in FIG. 6 (A) and used in the form of ribs.
Further, not limited to the rod shape and the thick plate shape, any shape of the 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 these, and a slightly curved resin sheet 1 is also allowed.
FIG. 7A shows a resin sheet 1 in which the facing surfaces of the fixed mold 12 for molding and the movable mold 13 are gently curved. When this molding die 10 is used, as shown in FIGS. (B1 and B2), a plastic molded product C in which the protruding member 5 is formed on the resin sheet 1 curved in a shallow dish shape can be obtained.

FIG. 8 (A) shows that the facing surface of the fixed mold 12 and the movable mold 13 is curved in a deep dish shape. When such a molding die 10 is used, as shown in FIGS. (B1 and B2), a plastic molded product D in which the protruding member 5 is formed on the resin sheet 1 curved in a deep dish shape can be obtained.

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

1 Resin sheet 2 Swelling part 2a Internal cavity 3 Through hole 5, 6 Protruding member 10 Molding mold 11 Cavity 20 Pressing member 21 Rod 22 Pin

Claims (6)

A fiber-reinforced plastic molded product in which a protruding member formed of resin is provided on the surface of a thermoplastic resin sheet in which continuous fibers are oriented.
A bulging portion formed so as to push the thermoplastic resin sheet from one side to the other side so as to protrude.
With a bulge or a through hole formed around the bulge.
The internal cavity of the bulging portion is formed so that the inner diameter expands from the top side to the back surface side of the bulging portion.
The protruding member of the thermoplastic resin sheet is made of a resin formed on the outside of the bulging portion, and is integrated with the internal space of the bulging portion and the resin filled inside the through hole.
A fiber reinforced plastic molded product characterized by this. The fiber-reinforced plastic molded product according to claim 1, wherein the through hole is formed at the top or side of the bulging portion. The fiber-reinforced plastic molded product according to claim 1, wherein the through hole is formed laterally away from the root of the bulging portion . It 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 forming a bulge on the other surface by pressing with a pressing member from one surface of the thermoplastic resin sheet.
The step of forming a through hole in the thermoplastic resin sheet and
The step comprises a step of molding 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. The molding of the fiber-reinforced plastic molded product according to claim 4 , 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. The method for molding a fiber-reinforced plastic molded product according to claim 4 , 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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