JPS5936848B2 - Molding method for fiber-reinforced plastic molded products - Google Patents

Description

Detailed Description of the Invention The present invention involves pressurizing and injecting a synthetic resin liquid into the molding gap formed between a lower mold and an upper mold while reducing the pressure in the molding gap, and then injecting the synthetic resin liquid into the molding gap. This relates to a molding method for fiber-reinforced plastic molded products that is cured and molded by curing and molding.The molding gap between the upper and lower molds is completely sealed, and the upper and lower molds are kept in contact with each other throughout the molding process. The present invention provides a method for molding a fiber-reinforced plastic molded product that can maintain the width of the gap at a predetermined size.

Conventional molding of fiber-reinforced plastic molded products involves placing preformed fiber mats, mainly glass fiber mats, as reinforcing fibers on the molded concave surface of the lower mold, or placing fiber cloth mats while preforming them. However, after that, the upper and lower molds are tightened and sealed using a large number of bolts and nuts around the entire periphery of both the upper and lower molds.
A method has been adopted in which a resin liquid is then pressurized and injected into a molding gap formed by a lower mold and an upper mold to harden and mold the resin. However, this method of molding plastic molded products requires the use of a large number of bolts to tighten both the upper and lower molds, which is complicated and time-consuming, and it is difficult to evenly tighten the entire mold. Moreover, since the viscosity of the synthetic resin liquid press-fitted into the molding gap is usually 3 to 5 poise, when the synthetic resin liquid is injected into the molding gap, the viscosity is 2 to 6 kg/Cd. In order to prevent the upper mold and lower mold from deforming even under such high injection pressure of the synthetic resin liquid, for example, the thickness of the plastic sander arch structure must be increased. Due to its structure, upper and lower molds must be manufactured, which inevitably increases the weight of the upper and lower molds for molding, making them difficult to handle. There is.

In view of the above drawbacks, as shown in FIG. By arranging two rod-shaped rubber plates 4, 5 in parallel across the suction port 3, the lower mold 1, upper mold 2, and two rod-shaped rubber plates 4, 5 can be used for sealing. After forming a gap and reducing the pressure in this sealing gap by suction using the suction port 3 to seal the upper mold 2 and the lower mold 1, the gap between the upper mold 2 and the lower mold 1 is A suction port (
A molding method in which a synthetic resin liquid is injected into the molding gap while reducing the pressure using a molding machine (symbols omitted in the drawings), the synthetic resin liquid is filled into the molding gap, and normal curing molding is performed. By adopting this, it is possible to make the upper mold, the lower mold, or both the upper and lower molds light in weight.

When molding a molded product filled with reinforcing fibers using the above method using these two rod-shaped rubber plates, a preformed reinforcing fiber mat is placed on the molding concave surface of the lower mold 1. A type in which a fiber mat is placed while being preformed, an upper mold 2 is placed on top of the fiber mat, and a sealing gap is formed by the lower mold 1, the upper mold 2, and the two rod-shaped rubber plates 4, 5. However, due to the repulsive force (spring back) of the reinforcing fibers placed on the molding concave surface of the lower mold 1, the two rod-shaped rubber plates 4 and 5, the upper mold 2, and the lower mold 1 It becomes difficult to form a gap of a predetermined size between them, and it becomes impossible to seal the inside of the gap with a suction.

Therefore, a method can be considered in which the height of the rod-shaped rubber plate is increased to form a gap, but in this method, the pressure in the gap is continued to be reduced by a suction, and both the upper mold 2 and the lower mold 1 are As the distance between the molds approaches a predetermined distance, the rod-shaped rubber plates 4 and 5 become distorted, making it impossible to maintain the seal in the sealing gap. In order to prevent this phenomenon, it is possible to increase the width of the rod-shaped rubber plates 4 and 5, but in such a case, the elastic repulsion force of the rod-shaped rubber plates themselves becomes too strong, so it is not possible to use suction alone. It becomes impossible to adjust the distance (interval) between the mold 2 and the lower mold 1 to a predetermined size. The method for molding a fiber-reinforced plastic molded product of the present invention is a method for molding a fiber-reinforced plastic molded product, which comprises curing and molding a synthetic resin within a molding gap formed between a lower mold and an upper mold. After laying and placing reinforcing fibers on the molding concave surface of the lower mold, two rubber tubes to which internal pressure is applied are placed over the entire periphery between the lower mold and the upper mold. Alternatively, by arranging them in parallel across the suction ports attached to the upper mold, a sealing gap is formed between the lower mold, the upper mold and the two rubber tubes, and then the sealing gap is formed between the lower mold, the upper mold and the two rubber tubes. The inside of the gap is depressurized and sealed using the suction port for the suction,
Thereafter, the synthetic resin liquid is pressurized into the molding gap while reducing the pressure in the molding gap using a suction port passed through the molding gap between the lower mold and the upper mold. As a result, it has been possible to provide a method for molding fiber-reinforced plastic molded products that eliminates all of the above-mentioned drawbacks.

The configuration of the present invention will be explained below based on illustrated embodiments.

In FIGS. 2 and 3, a reinforcing fiber mat 9 is laid and placed on the concave molding surface 8 of the lower mold 7, which is fixed to a frame or the like so as not to be deformed.

The reinforcing fiber mat 9 may be preformed beforehand and laid and placed, or it may be laid and placed while being preformed. After that, the two rubber tubes 1 to which internal pressure is applied are applied to the entire periphery of the lower mold 7.
0 and 11 are arranged in parallel, and then the upper mold 12 is placed on the lower mold 7. When the two rubber tubes 10 and 11 to which internal pressure is applied are arranged parallel to each other over the entire periphery of the lower mold 7, the lower mold 7, the upper mold 12, and the two rubber tubes 10 and 11 are formed. The suction suction port 13 is connected to the rubber tube 10 so that the sealing gap 15 can be depressurized and sealed by using the suction suction port attached to the lower mold 7 or the upper mold 12. In the figure, the suction suction port 13 attached to the upper die 12 is placed in a position sandwiched between the rubber tubes 10 and 11. It has been set up.

Note that even if the two rubber tubes are arranged with internal pressure already applied as described above, or if the upper mold 12
Of course, after fixing the rubber tube to the lower mold 7, an operation may be performed to apply internal pressure to the already installed rubber tube. Reference numeral 14 is a rubber packing for sealing.

This sealing rubber backing 14 is made of a material that will not be corroded by polyester resin or epoxy resin, which are general synthetic resins for molding, and like the packing spacer 18, it can be used as needed. In the illustrated embodiment, a rubber packing 14 is arranged along the outside of the backing spacer 18. After placing the upper mold 12 on the lower mold 7, mark 1 in the figure
The sealing gap 15 between the upper die 12 and the lower die 7 is sealed by suctioning the sealing gap indicated by 5 from the suction suction port 13 attached to the upper die 12.

At this time, when the degree of suction becomes high and the pressure difference between the internal pressure of the rubber tubes 10, 11 and the negative pressure in the sealing gap 15 becomes too large, the rubber tubes 10, 11
It is necessary to appropriately reduce the internal pressure of the rubber tubes 10 and 11 to prevent them from bursting. Next, a suction port for suction passing through the molding gap between the upper mold 12 and the lower mold 7 (that is, the gap into which the synthetic resin liquid for molding is injected) is attached to the upper mold 12 in the illustrated embodiment. At the same time, the pressure in the gap for the former mold is reduced by the suction from the suction port 16, and a predetermined synthetic resin liquid is injected from the synthetic resin liquid injection port 17 attached to the bottom of the upper mold 12. A predetermined amount of synthetic resin liquid is filled into the molding gap, and then the usual synthetic resin is cured and molded to form a desired plastic molded product.

The method for molding a fiber-reinforced plastic molded article of the present invention is constructed as described above, and internal pressure is applied to form a sealing gap 15 between the upper mold 12 and the lower mold 7. Since the rubber tubes 10 and 11 are used, before applying negative pressure to the sealing gap 15, the upper and lower molds 12 and 7 must be It is possible to maintain a sufficient height without being hindered by the repulsive force of the reinforcing fibers, and to form a gap of a predetermined size between the upper mold 12 and the lower mold 7. Also, when negative pressure is applied within the sealing gap 15, the rubber tube 10 to which the internal pressure is applied is
11 is gradually flattened to form a sealing gap 15 between the upper mold 12 and the lower mold 7 at a predetermined height. It is possible to form a molding gap that is held at a height.

Moreover, flattening of the rubber tubes 10 and 11 while applying negative pressure in the sealing gap 15 can be easily achieved by controlling the internal pressure of the tubes without applying any particularly large force to the rubber tubes. Furthermore, since the rubber tube can be deformed while maintaining the seal in the sealing gap 15, accurate molding can be performed while maintaining the predetermined height between the upper and lower molds 12 and 7. A gap can be easily formed, and the molding gap between the upper and lower molds can be sealed and the upper and lower molds can be fixed easily. In the method for molding a fiber-reinforced plastic molded article of the present invention having the above configuration, two rubber tubes 10 are used to completely seal the sealing gap 15 between the upper mold 12 and the lower mold 7; Specifically, it is preferable that the material 11 has a diameter of about 25 m1 that can withstand an internal pressure of 0.5k9/Cd, and it is preferable to apply an internal pressure of about 0.2kg/Cd when sealing. In addition, when suctioning and sealing the sealing gap 15, it is better to suction at 660T0rr or more, and if the suction is lower than 660T0rr, the degree of pressure reduction will be low and it will not be possible to achieve a complete press-tight seal. There is a risk.

In addition, when using a thin fiber-reinforced plastic material with a thickness of about 2 to 5 mm as the upper mold 12 in the method of the present invention, the flow and transition state of the synthetic resin within the molding gap, that is, the synthetic resin Since the state in which the liquid impregnates the reinforcing fibers can be visually observed from the upper part of the upper mold 12 through the upper mold 12, the molding operation can be performed while observing the behavior of the synthetic resin liquid during the molding process and the behavior during curing. It has the advantage of being able to recommend

The method for molding a fiber-reinforced plastic molded product of the present invention is constructed as described above. This is achieved by reducing the pressure in a sealing gap separate from the gap using a suction port that passes through the sealing gap, and the molding gap into which the synthetic resin liquid for molding is injected. This reduction in pressure is achieved by using a suction port that passes only into the forming gap.In other words, the pressure reduction in the sealing gap and the pressure reduction in the forming gap are completely separate and independent. Therefore, by highly reducing the pressure in the sealing gap, it is possible to perfect the pressure seal between the upper and lower molds, and also to prevent atmospheric suction due to seal leakage. Even if air bubbles occur in the sealing gap, the molding of the plastic can be completed without causing problems such as generation of bubbles in the molding gap.

Furthermore, as mentioned above, the pressure reduction for press-sealing between the upper mold and the lower mold and the pressure reduction in the molding gap are achieved by using separate suction ports, respectively. Since the injection pressure of the synthetic resin liquid can be lower than that of conventional methods, it is possible to use molds made of thin-walled, lightweight materials for the upper mold, lower mold, or both upper and lower molds. This has the effect that handling of the mold becomes extremely easy and molding operations can be performed easily. In addition, in the method of the present invention, a rubber tube to which internal pressure is applied is used to form the sealing gap between the upper and lower molds, so that it can be laid and placed on the molding concave surface of the lower mold. It is possible to form a gap high enough between the upper and lower molds to create a sealing gap without being hindered by the repulsive force of certain reinforcing fibers, and to apply negative pressure within the sealing gap. When the pressure inside the gap is reduced, the rubber tube can be gradually flattened to form a sealing gap with a predetermined height between the upper and lower molds. It is possible to sufficiently reduce the pressure in the sealing gap between the molds, and to completely seal the spaces between the upper and lower molds. Therefore, while reducing the pressure in the molding gap between the upper and lower molds using the suction, the injection pressure necessary to smoothly and quickly fill the synthetic resin liquid into the gap can be reduced by the conventional method. It has the effect of being able to be lowered step by step. Furthermore, as mentioned above, in the method of the present invention, a rubber tube is used to form a sealing gap, so when removing the mold after plastic molding, the internal pressure of the rubber tube is increased to remove the upper mold. There is also an effect that demolding between the mold and the lower mold and between the upper mold and the molded article can be easily performed.

In addition, in the vacuum assisted resin injection (ARI) molding targeted by the method of the present invention, when obtaining a fiber-reinforced plastic molded product by this method, it is necessary to improve the fluidity of the resin within the molding gap. Therefore, bulky reinforcing fibers with a large repulsive force are generally used.For this reason, in the case of packing seals that use rod-shaped rubber plates, at least the thickness (height) of the packing is However, in the present invention, since a rubber tube is used to form the sealing gap, the diameter of the tube is enlarged to be larger than the volume of the reinforcing fibers, and then the reinforcing fibers are compressed in advance. Since the pressure reduction in the gap can be started, there is no need to press the reinforcing fibers in advance, and a complete seal can be achieved in the sealing gap.

In addition, in the case of packing seals made of rod-shaped rubber plates, there is a risk that various compression strains may occur in the rod-shaped rubber plates during the plastic molding process depending on their size, shape, etc., making the sealing effect unstable. However, since the method of the present invention uses a rubber tube, by adjusting the internal pressure of the tube as necessary, the distortion that occurs in the rubber tube during the plastic molding process can be suppressed, and the sealing effect can be improved. It also has the effect of being completely expressed.

[Brief explanation of drawings]

FIG. 1 is a partially cutaway sectional view showing an example of a conventional method for molding a fiber-reinforced plastic molded product, and FIG. 2 is a front view showing an example of the method for molding a fiber-reinforced plastic molded product of the present invention. FIG. 3 is an enlarged sectional view taken along a line in FIG. 2. 7...Lower mold, 8...Molding concave surface of the lower mold, 9...Glass fiber for reinforcement, 10, 11...
...Rubber tube to which internal pressure is applied, 12...
... Upper mold, 13 ... Suction port for suction passing through the sealing gap, 15 ... Sealing gap, 1
6... suction port for suction passed through the molding gap, 17... injection port for synthetic resin liquid.

Claims (1)

[Claims] 1 In a method for molding a fiber-reinforced plastic molded product, which consists of curing and molding a synthetic resin within a molding gap formed between a lower mold and an upper mold, the molding concave surface 8 of the lower mold 7 is After laying and placing the reinforcing fibers 9, two rubber tubes 10 and 11 to which internal pressure is applied are placed over the entire periphery between the lower mold 7 and the upper mold 12. By arranging the suction ports 13 attached to the upper mold 12 in parallel, a sealing gap 15 is created between the lower mold 7, the upper mold 12, and the two rubber tubes 10 and 11. The sealing gap 15 is then depressurized and sealed using the suction suction port 13, and then a suction is formed which leads into the molding gap between the lower mold 7 and the upper mold 12. A method for molding a fiber-reinforced plastic molded product, which comprises pressurizing a synthetic resin liquid into the molding gap while reducing the pressure in the molding gap using a suction port 16.