JPH07118991B2 - Resin mold - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a mold for molding a resin product by performing vacuum deaeration while injecting resin into the mold.

[0002]

2. Description of the Related Art A method called resin transfer molding (hereinafter referred to as RTM) is one of the manufacturing methods for molding a resin molded product by injecting resin into a mold. This R
The TM method will be described with reference to FIG. A convex mold 1 that is usually an upper mold and a concave mold 2 that is usually a lower mold are prepared, and the molding portions 3 of both molds are cleaned and a mold release agent is applied. Next, the seal packing 5 is attached to the seal groove formed around the molding portion 3 of the concave mold 2, and the gel coat is sprayed on the molding portion 3 with a spray gun or the like, and the gel coat is initially cured for several minutes. wait. Next, a glass mat, which serves as a reinforcing material for the product, is set on the gel coat. At this time, the glass mat must be set not only inside the molding part 3 but also outside the seal packing 5.
This is because when the resin is injected in the next step, if there is no escape area for the air in the molding part 3, many fine holes called porosity and pits will occur in the molded product, so the fibers of the glass mat will In order to allow the air in the molding part 3 to escape,
This is an essential method for RTM. Next, both molds 1 and 2 are closed and clamped, a resin injection nozzle is connected to the injection port 15 of the upper mold 1, the injection machine is operated to inject the resin, and the completion of curing of the resin is waited. After a predetermined time has elapsed, the mold is opened and the product is taken out.

In the above-mentioned conventional RTM method, since air is entrained when the resin is injected, when this molded product is coated and baked, pinholes, blisters, etc. occur. As a countermeasure for this, it is possible to adopt the vacuum degassing method used in the molding of sheet molding compound (hereinafter referred to as SMC), but unlike the SMC method, the RTM method melts into the mold during molding. Since the resin is injected, if the vacuum deaeration is simply performed, the injected resin may flow into the vacuum pump system, and if the resin gets around the molding part of the mold, it is difficult to remove it. Therefore, the type structure is limited to simple ones.

The applicant has previously filed a patent application for an invention of a resin molding die in which the vacuum degassing method can be adopted without problems in the molding by RTM and there is no fear of pinholes or blisters in the molded product. (See JP-A-3-19814). The outline of the present invention will be described below. Figure 3
4A is a cross-sectional view of a state in which the mold is clamped, for molding the front end panel of the automobile shown in FIG. 4, and the molding part 3 shows a cross section taken along line XX of FIG. A seal groove similar to that of a conventional RTM is formed around the molding portion 3 of the recessed mold 2 and a seal packing 5 is installed, and a resin pool for an overflow is provided outside the seal packing 5 over the entire circumference. A groove 7 is formed, and a second seal groove is formed on the entire outer circumference of the groove 7, and a seal packing 6 is installed. An injection block 4 is provided on the convex mold 1, and a resin injection port 15 of the injection block 4 is opened in the molding section 3. Further, the vacuum deaeration block 8 is installed so as to open in the space between the seal packings 5 and 6, and the nipple 9 is connected to the vacuum devices 10 to 14 outside the mold. The vacuum device is a plug with valve 10, a vacuum adjusting valve 11, a vacuum gauge 12,
It is connected to a vacuum hose (not shown) via a socket 13 with a valve and a plug 14.

RTM molding using the above mold will be described below. The steps up to clamping the two molds 1 and 2 are the same as in the RTM method. A resin injection nozzle is connected to the injection port 15 of the upper mold 1, and the injection machine is operated to inject a molten resin such as unsaturated polyester resin. At this time, the valves 10 and 13 of the vacuum system are opened to evacuate the inside of the resin reservoir groove 7, and the inside of the molding part 3 is evacuated via the glass mat set on the seal packing 5. The degree of vacuum in the mold is adjusted by the vacuum adjusting valve 11. After a lapse of a predetermined time until the curing of the resin is completed, the mold is opened and the molded product is taken out from the molding unit 3. As described above, there is no possibility that the molding portion is degassed when the resin is injected, and the resin that has exceeded the inner seal packing is trapped in the resin reservoir groove and flows into the vacuum system.

[0006]

DISCLOSURE OF THE INVENTION Problems to be Solved by the Invention
In the molding die described in Japanese Patent Publication No. 14, the air in the molded product can be significantly reduced, but when the molded product becomes large, gelation begins during the resin injection, and the air remaining in the product It becomes difficult to discharge the air, and it becomes impossible to completely remove the air in the molded product.

It is an object of the present invention to provide a resin molding die capable of completely eliminating the air in the molded product even when the molded product is large, without the possibility of the injected resin flowing into the vacuum system. To do.

[0008]

SUMMARY OF THE INVENTION According to the present invention, an inner and outer double resin pool groove is formed to surround a molding portion of a mold, and a first space is formed between the inner and outer double resin pool grooves and the outer periphery of the outer resin pool groove. The resin molding die is provided with the seal material and the second seal material, and provided with deaeration ports communicating with the vacuum suction device at the portions facing both the resin reservoir grooves.

[0009]

[Function] To mold a resin using this mold, one side of the mold that has been opened is set with a glass mat that serves as a reinforcing material for the product, the mold is clamped, and vacuum suction is applied from both degassing ports. Keep the vacuum. When molten resin is injected into the molding portion in this state, degassing occurs even when the molten resin filling the molding portion flows out of the molding portion and reaches the inner resin pool groove or the inner first seal material. Continued, even in the case of a large molded product, the air entrapped in the resin is completely discharged out of the mold. Further, there is no possibility that the resin flowing out beyond the molding portion will be trapped inside the resin pool and flow into the vacuum device side.

[0010]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 1 is an enlarged cross-sectional view of a seal portion and a vacuum degassing portion of a molding die for molding a front end panel of an automobile in the same manner as shown in FIGS. A resin reservoir groove 21 for an overflow is formed around the molding portion 3 of the concave mold 2 over the entire circumference, and a second overflow resin is formed on the outer circumference over the entire circumference. Forming a resin reservoir groove 22 for The convex mold 1 is formed with deaeration ports 16 and 18 at the portions facing the resin pool grooves 21 and 22 of the concave mold 2, respectively.
6 and 18 are out-of-mold vacuum devices similar to those shown in FIG.
Connect to 0-14. Further, the convex mold 1 is formed with a first seal groove at a portion facing the middle of the resin pool grooves 21, 22 of the concave mold 2 and is fitted with an inner seal material 17 of corner rubber. A second seal groove is formed in a portion facing the outer periphery of the resin pool groove 22 and a hollow tube-shaped rubber outer seal material 19 is mounted.

In RTM molding using the molding die shown in FIG. 1, the preparatory step before mold clamping is performed in the same manner as described above with reference to FIG. As the mold clamping progresses, first the outer sheath
As shown in FIG. 2, the sealing material 19 comes into contact with the concave mold 2 and seals inside the mold.
To At this stage, the inside of the mold is rapidly degassed from the degassing ports 16 and 18 by the vacuum device. Next, when the mold clamping is completed, as shown in FIG.
As shown in FIG. 3, the inner seal material 17 also contacts the concave mold 2 and the inner and outer seal materials 17, 19 are in a sealed state, so that the deaeration from the deaeration port 18 has its function after the deaeration is completed. And the degassing from the degassing port 16 continues. When the suction by the vacuum device is weakened and the injection of the resin is started when the inside of the molding unit 3 is sufficiently deaerated, the air entrapped in the resin is discharged, and no air remains in the resin molded product, and the molding unit The resin flowing out beyond 3 is trapped in the resin reservoir groove 21 and the resin is prevented from being sucked up to the degassing port 16.

Next, another embodiment will be described. Figure 1
In the above, the sealing function of the inner seal material 17 is intentionally slightly weakened so that the molten resin is prevented from flowing out while the mold is clamped, but the degree of sealing is such that deaeration is possible. Other configurations are the same as those described above.

In the state where the mold is clamped, the outer seal material 19 is completely sealed and the inner seal material 17 is in a sealed state such that it can be deaerated. The inside of the mold is rapidly degassed from the degassing ports 16 and 18 by the vacuum device, and the inside of the molding unit 3 is kept in vacuum. In this state, suction from the degassing port 16 is temporarily stopped. Next, when the injection of the molten resin is started, the resin reaches the inner seal material 17 from the molding portion 3 through the resin reservoir groove 21, and the outflow is stopped to seal this portion. Therefore, the deaeration function from the deaeration port 18 is blocked. When the suction from the degassing port 18 is stopped and the suction from the degassing port 16 is restarted, the air entrained in the subsequent resin in the molding unit 3 is discharged to the outside of the mold, and no air remains in the molded product. The suction of the resin to the degassing port 16 is also prevented.

The present invention includes an engine hood, a fender,
Applicable to molding automobile outer panels such as roofs and trunk lids, and also applicable to automotive structural members such as suspensions, lower arms, upper arms, and frames. Is. Further, it can also be applied to the molding of building structures other than automobile parts such as engine hoods.

[0015]

INDUSTRIAL APPLICABILITY According to the present invention, when the vacuum degassing method is applied to a method of injecting a resin into a mold for molding, it is possible to prevent defective molding or mechanical failure of the product and obtain a high quality molded product. There is an effect.

[Brief description of drawings]

FIG. 1 is a sectional view of an embodiment of the present invention.

FIG. 2 is a partially enlarged view of FIG.

FIG. 3 is a cross-sectional view of a conventional molding die.

FIG. 4 is a front view of a molded product.

[Explanation of symbols]

 1 Convex type 2 Concave type 3 Molding part 16 Degassing port 17 Inner sealing material 18 Degassing port 19 Outer sealing material 21 Resin pool groove 22 Resin pool groove

Continuation of front page (51) Int.Cl. ⁶ Identification number Office reference number FI technical display area B29L 31:30

Claims (1)

[Claims] 1. An inner and outer double resin reservoir groove is formed to surround a molding part of a mold, and a first seal material and a second resin reservoir groove are provided between the inner and outer double resin reservoir grooves and on the outer periphery of the outer resin reservoir groove. And a deaeration port that communicates with a vacuum suction device, respectively, is provided at a portion facing both of the resin reservoir grooves.