JP2001277255A - Method for molding fiber-reinforced plastic and hole forming collar - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide novel fiber-reinforced plastic which can secure enough strength around a hole and a hole forming collar used in the method. SOLUTION: A hole processing pin N is installed in the cavity of a mold K, the cylindrical collar 1 having a cylindrical collar main body 2 and a rib 3 for straightening the flow of a fiber-reinforced resin is fitted to the pin N, and the resin is press-molded. The right and left flows of the resin F divided by the collar main body 2 are combined to overlap each other vertically on the downstream side so that the reinforcing fibers in the resin flow surely around the hole, securing enough strength around the hole.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for press-molding or injection-molding a fiber-reinforced plastic molded article and a novel hole-forming collar used for molding a fiber-reinforced plastic molded article with holes.

[0002]

2. Description of the Related Art In general, a fiber-reinforced plastic molded product obtained by mixing a reinforcing fiber into a resin exhibits strength equivalent to that of metal, is lightweight and has excellent moldability. It has been widely adopted as various vehicle parts such as engine covers and plackets.

[0003] Among such fiber-reinforced plastic molded articles, particularly, sheet-like articles and 50 to 150 mm
In the case of a fiber-reinforced plastic molded article using the above long fibers, injection molding is generally difficult, and therefore most of the molded articles are molded by press molding.

As a press molding method, first, as shown in FIG. 9, a composite material in which fiber mats G, such as glass long fibers, are laminated between thermoplastic resin sheets P, P, P made of, for example, polypropylene or the like. A stampable sheet (S) is prepared and cut into a predetermined length by a cutter (C) as shown in FIG. Next, this plank B
As shown in FIGS. 10 (2) and 10 (3), the (raw material) is heated to about 200 ° C. by a heater H to soften it.
Lower mold K pre-heated to a predetermined temperature (40-65 ° C)
Set on 1. Thereafter, as shown in FIG. 10 (4), the upper mold K is heated from above to a predetermined temperature.
When 2 is lowered and pressurized, the blank B in the form of a sheet is radially expanded and filled into the cavity and press-molded into a predetermined shape. When the temperature of the mold is lowered and the resin in the cavity is hardened, the mold is opened and the molded product R is taken out as shown in FIGS. By punching a mounting hole M or the like at a predetermined position using a punch J or the like, a fiber-reinforced plastic molded article R with a hole having a predetermined shape is obtained.

[0005]

Incidentally, the fiber-reinforced plastic molded product obtained by such a conventional method needs to go through two steps such as a press molding step and a step of drilling a mounting hole M. Therefore, productivity was not good. Further, since the mounting hole M was drilled by the piercing punch J or a drill, a crack or the like occurred during the drilling work, or a part of the fiber protruded from the end face of the mounting hole M. There have been inconveniences such as irritating the worker's skin to cause discomfort or generating unnecessary shavings in large quantities.

Further, when a collar D made of metal or resin is press-fitted after forming a hole as shown in FIGS. 11 and 12 (A) in order to reinforce the hole, a crack is formed around the hole at the time of press-fitting. In addition, when the metal color D is used, the metal color D must be removed each time it is recycled. There is a disadvantage that it becomes expensive. As shown in FIG. 12 (B), it is possible to maintain a certain level of strength by increasing the thickness around the hole. However, not only an extra resin material is required, but also the surrounding space is reduced. It is necessary to increase the size, and when the fixing component is a bolt or the like, there is a problem that an unnecessarily long one is required.

For this reason, recently, a hole-forming pin is previously provided at a predetermined drilling position in a cavity, and a resin collar serving as a reinforcing member around the hole is inserted into the hole-forming pin before press forming. A method has been proposed in which a required number of mounting holes M are formed at the same time as press forming, thereby eliminating the drilling operation itself and making recycling easy.

However, if the holes N and the collars D are provided in advance in the cavity as described above, for example, a molded article having a shape as shown in FIG. When press-molding R, etc., the resin F flowing to the hole-forming pin N side as shown in FIG.
Are distributed to the left and right according to the color D, and flow downstream of the color D, respectively.
A rectangular weld (a resin-rich portion where fibers are not connected) that partially extends in the vertical direction (thickness direction) at its tip as shown in FIGS. There is a problem that W is formed and strength around the hole is significantly reduced.

Accordingly, the present invention has been devised to effectively solve such problems, and an object of the present invention is to provide a novel fiber-reinforced plastic molding method and a hole forming method capable of sufficiently securing strength around a hole. It is intended to provide a color for use.

[0010]

Means for Solving the Problems In order to solve the above problems, the first and second inventions are directed to a thermoplastic or thermoplastic resin containing a long fiber having a length of 50 to 150 mm or more. After the thermosetting reinforcing fiber-containing resin is positioned between the molds, the molds are brought close to each other and filled into the cavity to press-mold a fiber-reinforced plastic molded product having a desired shape. A pin for drilling holes is erected at a predetermined position in the inside, and a cylindrical collar main body to be inserted into the hole drilling pin and a reinforcing fiber-containing resin distributed to the left and right by the collar main body are further thickened. A press-molding is carried out after attaching a hole forming collar composed of a rib which is rectified so as to be distributed in the upper and lower directions.

That is, as described above, when press molding is performed in a state where a cylindrical collar is attached to a hole-forming pin which is simply provided upright at a predetermined position in a cavity, the resin flowing to the collar side is here. After being distributed to the left and right, by merging as it is on the downstream side, a weld extending in the thickness direction is formed and the entanglement of the fiber is partially eliminated, so that the strength around the hole is significantly reduced.

On the other hand, according to the method of the present invention, a hole forming collar comprising a cylindrical collar body and ribs for further distributing the resin distributed to the left and right in the collar body to either upper or lower in the thickness direction is provided. Since the resin is used, the resin distributed to the left and right in the collar main body is immediately further distributed to either the upper and lower sides in the thickness direction by the ribs, and then joined so as to overlap the upper and lower sides in the thickness direction on the downstream side. As a result, the reinforcing fibers in the resin sufficiently wrap around the hole, and the positions of the welds extending in the thickness direction can be dispersed, so that the strength around the hole can be sufficiently ensured.

According to a third aspect of the present invention, there is provided a fiber-reinforced plastic having a desired shape by injecting a thermoplastic resin which has been softened by heating or a soft thermosetting fiber-containing resin before heating into a cavity. In the method of injection-molding a molded product, a hole-forming pin is erected at a predetermined position in the cavity in advance, and a cylindrical collar body inserted into the hole-forming pin and a left-right In this case, the injection molding is performed after attaching a hole forming collar composed of a rib for rectifying the reinforcing fiber-containing resin to be further distributed upward or downward in the thickness direction.

That is, the above-mentioned problem is particularly problematic in lengths of 50 to
This phenomenon occurs remarkably when press-molding using a long fiber of 150 mm or more, but the strength of the weld portion similarly decreases even in the case of injection molding or when using a short fiber.
For this reason, in the case of injection molding, similarly, in the case of injection molding, a hole forming collar provided with a rib is attached to a side surface of a collar body to be inserted into a hole processing pin, and then injection molding is performed. Even in the obtained fiber-reinforced plastic molded product, it is possible to sufficiently secure the strength around the hole.

According to a fourth aspect of the present invention, the hole forming collar is formed from the reinforced fiber-containing resin, and the reinforced fiber content of the collar is made higher than that of the fiber-reinforced plastic molded product. The area around the hole of the plastic molded product can be sufficiently reinforced, and at the same time, the removal work at the time of recycling is not required, so that the recycling cost can be reduced.

According to a fifth aspect of the present invention, there is provided a hole which is previously attached to a hole processing pin in a cavity when a fiber-reinforced plastic molded product having a hole is pressed or injection-molded. In the forming collar, a cylindrical collar main body inserted into the hole processing pin, a rib for rectifying the reinforcing fiber-containing resin flowing from the lateral direction so as to be distributed up and down, and a rotation regulating the rotation of the rib. With the use of such a collar for forming a hole, it is possible to obtain an excellent action and effect as in the method of the present invention, and therefore, a fiber-reinforced plastic molding having excellent strength around the hole. The product can be easily obtained by press molding.

As a specific rib shape for exhibiting such a function, a pair of upper and lower weir-shaped plates provided on both sides of the collar body, respectively, as described in claim 6 or claim 7. 9. A pair of inclined blades provided on both sides of the collar body as shown in FIG.
As shown in (1), an inclined plate or the like spirally provided on the downstream side of the collar body can be used.

[0018]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Next, a preferred embodiment of the present invention will be described with reference to the accompanying drawings.

FIG. 1 shows an embodiment of a hole forming collar 1 according to the present invention.

As shown in FIG.
Is a hole forming pin N set up in the cavity of the mold K.
And a rib 3 provided on both sides of the collar body 2 for rectifying the resin.
3 and a detent 4 provided at the insertion end thereof.

The ribs 3, 3 are formed of a pair of rectangular weir-shaped plates 3a, 3b, one of which is provided on the upper end side of the collar body 2 and the other of which is the other weir-shaped plate 3b.
Are provided on the lower end side of the collar body 2, respectively. The collar body 2 is formed by the weir-shaped plates 3a and 3b.
The resin distributed to the left and right is blocked by upper and lower portions, respectively, and rectified from the lower or upper portion to the downstream side of the collar body 2.

The detent 4 is formed by forming a notch 5 in a part of a flange-shaped flange 4a extending from the insertion end of the collar body 2, and the notch 5 is formed near the pin N for forming a hole. The ribs 3 and 3 are positioned by fitting them into the projections 6 provided on the main body 2 and the rotation of the ribs 3 and 3 and the collar body 2 are prevented.

In the method of the present invention, when the above-mentioned fiber-reinforced resin material (blank B) is press-molded, the hole-forming collar 1 having such a shape is formed as shown in FIGS. Pin N for forming holes set up inside
And then press-formed in the same manner as before to form the necessary mounting holes M
Is formed.

That is, the resin which has flowed in the vicinity of the hole forming collar 1 due to the pressure of the press is first distributed to the left and right by the collar body 2, and then at the lower end side (rotation stop 4 side), As shown in FIG. 5, the fibers in one of the resins distributed to the left and right are dammed together with the resin F by the weir-shaped plate 3b to regulate the flow, while the fibers in the other resin are dispersed together with the resin. It flows around the side of the collar body 2 as it is, and flows downstream of the collar body 2 so as to hold it.
Along the rear surface of the weir-shaped plate 3b.

On the other hand, on the upper end side, as shown in FIG. 6, the fibers in the other resin which are distributed to the left and right are blocked together with the resin by the weir-shaped plate 3a to regulate the flow. On the other hand, the fibers in one of the resins blocked by the weir-shaped plate 3b are kept together with the resin as they are in the color main body 2.
And flows downstream of the collar body 2 to reach the back side of the weir-shaped plate 3a along the collar body 2 as it is.

Therefore, in the molded article R thus formed, a weld line W extending in the circumferential direction is formed downstream of the collar body 2 as shown in FIG. The reinforcing fibers are divided vertically and flow effectively so as to surround the collar body 2 vertically. As a result, even if the reinforcing fibers are made of long fibers, the fibers sufficiently reach around the hole together with the resin, so that it is possible to secure the original sufficient strength of the fiber-reinforced resin around the hole.

In other words, in the conventional method, the weld line W has a rectangular cross section extending in the thickness direction as shown in FIG. 15, whereas in the method of the present invention, the weld line W is mainly formed by the collar body 2. Since the reinforcing fibers are formed so as to extend in the circumferential direction, and the reinforcing fibers are uniformly present around the entire hole, excellent strength can be exerted particularly against a tensile force or the like that tends to concentrate around the hole.

Here, since the hole forming collar 1 according to the present invention is integrated with the molded product R after press molding, it is formed from a reinforcing fiber-containing resin of the same material as the molded product R in consideration of recyclability and the like. It is desirable to do. For example, the resin constituting the molded article R generally includes thermoplastic resins such as polypropylene, polyamide, polybutylene terephthalate, and polyethylene terephthalate, and thermosetting resins such as unsaturated polyester and epoxy phenol. It is preferable to use these resins also for the resin constituting the forming collar 1. In addition, glass fibers, polyester fibers, and carbon fibers are frequently used as the reinforcing fibers to be mixed in the resin. Therefore, it is desirable that the reinforcing fibers mixed into the hole forming collar 1 also use these reinforcing fibers. .

Further, since the hole forming collar 1 is used as a reinforcing member around the hole of the mounting hole M which requires strength, the strength is set to be at least higher than the base material strength of the molded product R. It is necessary to increase the amount of the reinforcing fibers to be increased. For example, the compounding amount of the reinforcing fiber of the fiber-reinforced plastic molded article R used as a vehicle component is about 30 watts.
In general, the content of the reinforcing fibers in the hole forming collar 1 used is at least 30 wt.
% Or more. This makes it possible to manufacture a lightweight, high-strength product at low cost without increasing the reinforcing fiber content of the molded product R.

FIGS. 7 and 8 show another embodiment of the hole forming collar 1 according to the present invention.

First, in the hole forming collar 1 shown in FIG.
An inclined plate 3c protruding substantially horizontally from the side surface of the collar body 2 and extending obliquely from the lower end to the upper end side is employed, and a detent plate 4a vertically extending upstream of the color main body 2 as the detent 4 is used. It has been adopted.

As a result, one of the resins, which is divided right and left by the collar body 2 as shown by the arrow in the figure,
It flows so as to sink under the inclined plate 3c, and the other resin is
Since the fluid flows so as to be lifted along the inclined plate 3c, the reinforcing fibers flow effectively so as to embrace the collar body 2 around the collar body 2 as in the above-described embodiment, and the strength around the hole is reduced. It is possible to secure enough. Moreover, in the hole forming collar 1 according to the present embodiment, the flow of the resin around the hole is smoother than in the method of blocking a part of the resin as in the above embodiment, so that higher quality is obtained. Can be obtained.

On the other hand, the hole forming collar 1 shown in FIG. 8 is provided with a pair of inclined plates 3d and 3e which are respectively inclined in the vertical direction on the side surface of the collar main body 2. It is like removing a part of the middle part (downstream side) of the hole forming collar 1 shown. Thereby, the same resin flow as that of the hole forming collar 1 shown in FIG. 7 can be obtained, and the same effect can be obtained. In addition, in the present embodiment, the hole forming collar 1 shown in FIG. In addition to the smoothness of the resin flow, the number of materials used can be reduced.

In the above-described embodiment, the case of press molding has been described. However, the shortage of fibers in the weld line W formed around the hole can be similarly caused in the case of injection molding or the case of using short fibers. Therefore, even in the case of injection molding, a fiber-reinforced plastic molded product obtained by injection molding by inserting the hole forming collar 1 in advance into the hole forming pin N in advance and mounting the same in the same manner as described above, and then performing injection molding. Even so, the strength around the hole can be sufficiently ensured.

The collar body 2 forming the hole forming collar 1 is not limited to a cylindrical shape.
If the cross-sectional shape is formed into an elliptical or polygonal cylindrical body together with the hole forming pin N, the rotation is regulated while being inserted into the hole forming pin N. Therefore, the detent 4 itself is also omitted. Becomes possible.

The material forming the hole forming collar 1 is not limited to the above-described resin, if sacrificing recyclability, but may be other materials such as metal and ceramic. A material having excellent strength and wear resistance may be used. Further, the collar body 2 and the ribs 3 constituting the hole forming collar 1 may be formed of different materials, for example, the collar body 2 may be formed of metal and the rib 3 may be formed of resin.

[0037]

In summary, according to the present invention, it is possible to flow the reinforcing fiber sufficiently around the hole so that the strength around the hole does not decrease even if the hole is formed simultaneously with the forming. In addition, excellent effects such as sufficient securing of the original strength of the fiber-reinforced plastic can be exhibited.

[Brief description of the drawings]

FIG. 1 is a perspective view showing an embodiment of a hole forming collar according to the present invention.

FIG. 2 is a plan view showing the vicinity of a hole around a fiber-reinforced plastic molded product obtained by the method of the present invention.

FIG. 3 is a sectional view showing the vicinity of a hole around a fiber-reinforced plastic molded product obtained by the method of the present invention.

FIG. 4 is a conceptual diagram showing a weld line around a hole of a fiber-reinforced plastic molded product obtained by the method of the present invention.

FIG. 5 is a conceptual diagram showing the flow of resin at the position of line AA in FIG. 3;

FIG. 6 is a conceptual diagram showing the flow of resin at the position of line BB in FIG. 3;

FIG. 7 is a perspective view showing another embodiment of the hole forming collar according to the present invention.

FIG. 8 is a perspective view showing another embodiment of the hole forming collar according to the present invention.

FIG. 9 is a perspective view showing an example of a composite material (a stampable sheet) serving as a material of a fiber-reinforced plastic molded product by press molding.

FIG. 10 is an explanatory view showing an example of a conventional fiber-reinforced plastic molding step by press molding.

FIG. 11 is a plan view showing around a hole of a fiber-reinforced plastic molded product obtained by conventional fiber-reinforced plastic molding.

FIG. 12 is a cross-sectional view showing the vicinity of a hole of a fiber-reinforced plastic molded product obtained by conventional fiber-reinforced plastic molding.

FIG. 13 is a perspective view showing a battery clamp which is an example of a conventional fiber-reinforced plastic molded product.

FIG. 14 is a conceptual diagram showing a flow of resin around a hole by conventional press molding.

FIG. 15 is a conceptual diagram showing a weld line around a hole obtained by conventional press molding.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Hole forming collar 2 Collar body 3 Rib 3a, 3b Weir plate 3c Inclined plate 3d, 3e Inclined blade 4 Detent 4a Flange 4b Detent plate 5 Notch 6 Projection F Resin K Die M Mounting hole N Hole Forming pin W Weld line

Claims (8)

[Claims] After placing a heat-softened thermoplastic or a soft thermosetting reinforcing fiber-containing resin before heating between molds, the molds are brought close to each other and filled into the cavity to form a desired shape. In a method for press-molding a fiber-reinforced plastic molded product, a hole-forming pin is erected at a predetermined position in the cavity in advance, and a cylindrical collar body inserted into the hole-forming pin and the collar are inserted into the hole-forming pin. A fiber characterized by attaching a hole forming collar consisting of a rib for rectifying the reinforcing fiber-containing resin distributed to the left and right in the main body so that the resin is further distributed upward or downward, and then press-molding the fiber. Reinforced plastic molding method. 2. The reinforcing fiber has a length of 50 to 150 m.
The fiber-reinforced plastic molding method according to claim 1, wherein a long fiber of m or more is used. 3. A method of injecting a heat-softened thermoplastic or a thermosetting resin containing a soft thermosetting reinforcing fiber before heating into a cavity to injection-mold a fiber-reinforced plastic molded product having a desired shape. The drilling pin is set up at a predetermined position, and the cylindrical collar body to be inserted into the drilling pin and the reinforcing fiber-containing resin distributed to the right and left by the collar body are further vertically mounted on the drilling pin. A method for molding a fiber-reinforced plastic, comprising: mounting a collar for forming a hole comprising a rib for rectifying so as to be distributed to any one of the above; 4. The method according to claim 1, wherein the hole forming collar is molded from the resin containing the reinforcing fiber, and the content of the reinforcing fiber is higher than that of the molded article of the fiber reinforced plastic. The method for molding a fiber-reinforced plastic according to the above. 5. A cylinder to be inserted into said hole-forming pin in a hole-forming collar which is previously attached to a hole-forming pin in a cavity when a hole-formed fiber-reinforced plastic molded product is pressed or injection-molded. -Shaped collar body, a rib for rectifying the reinforcing fiber-containing resin distributed to the left and right in the collar body further upward or downward, and a detent for regulating the rotation of the rib. Hole forming collar. 6. The hole forming collar according to claim 5, wherein the rib comprises a pair of upper and lower weir-shaped plates provided on both sides of the collar main body, respectively. 7. The hole forming collar according to claim 5, wherein the rib comprises a pair of inclined blades provided on both sides of the collar body. 8. The hole forming collar according to claim 5, wherein the rib comprises an inclined plate spirally provided on a downstream side surface of the collar body.