JPS63168320A - Compression molding tool for thermosetting resin - Google Patents

Abstract

PURPOSE:To prevent exhaust ports for air suction from being blocked by molding material, and consequently obtain a compression molding tool for thermosetting resin, by which a high quality molded item having smooth surface is produced, is obtained by a structure wherein an annular groove, which locates on the side of a part communicating to a molding space nearer than the opening positions of the exhaust ports and which lies deeper than the opening positions of the exhaust ports, is formed on the underside of an introduction chamber. CONSTITUTION:A groove part 29, which locates inside the opening positions of exhaust ports 17..., is provided along the whole periphery on the underside of an introduction chamber 9 communicating with a molding space 6. During compression molding material A, which is pushed out through the lower part of the molding space 6 and accompanies with air or gas component, flows in the groove part 29 before it reaches the opening parts of the exhaust ports 17..., resulting in service the side wall of the groove part 29 as the bank part to check the efflux of the molding material from the groove part, and preventing the molding material from dissipating in the introduction chamber 9. As a result, no blockage of the exhaust ports 17... by the molding material flowing in the introduction chamber 9 occurs, and the air in the molding space 6 and the gas in the molding material can be surely exhausted before the final stage of compression. Accordingly, no fear of bubbles, which cause to develop pores and blisters, from being entrapped in the molding material during compression molding occurs and a high quality molded item B having smooth surface is obtained.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention is a method for compression molding a prepreg material formed into a sheet by kneading a thermosetting resin or this thermosetting resin with a reinforcing material. Regarding molds.

[Prior art]

In this type of mold, when the molding space between the upper mold and the lower mold is filled with molding material and compression molding is performed, the air in the molding space and the gas contained in the molding material are released during mold clamping. Until completion, the flow of molding material forces it out of the molding space.

However, if this air or gas is not handled properly, compression molding will be completed with this gas still encapsulated inside the molding material, resulting in many small holes and bulges on the surface of the molded product. There was a problem that surface defects such as

Conventionally, in order to prevent the occurrence of surface defects as described above, when compression molding a molding material, the molding space is airtightly isolated from the outside, and the inside of this molding space is evacuated by an exhaust device. Molds have been developed that forcibly eliminate air in the space and gas in the molding material.

[Problem that the invention seeks to solve]

However, since the exhaust port for exhausting the inside of the molding space is provided at the bottom of the molding space into which molding material accompanied by air and gas flows during the compression stroke, the exhaust port may be blocked by the flowing molding material. Sometimes I got lost.

For this reason, until the molding material is densely filled into the molding space, the air in the molding space and the gas in the molding material may not be completely removed, making it difficult to prevent surface defects from occurring. There was room for small improvements, such as hindering performance.

The present invention was made based on these circumstances, and
The purpose of the present invention is to provide a mold for compression molding a thermosetting resin, in which a high-quality molded product with a clean surface can be obtained without blocking the exhaust port for air suction with molding material.

[Means for solving problems]

Therefore, in the present invention, a molding space for compression molding a thermosetting resin molding material is formed between the upper mold and the lower mold, and a ring-shaped introduction chamber continuous to the lower part of this molding space. An exhaust port connected to the exhaust device is provided on the upper surface of the lower mold, which is the bottom surface of the chamber, and a sealing member is installed on either of the molds to airtightly shut off the molding space and the introduction chamber until the final stage of compression. Assuming a mold for compression molding thermosetting resin with a It is characterized by forming a ring-shaped groove that is also recessed.

[Effect]

According to this configuration, during the compression molding process, the molding material containing air and gas extruded from the lower part of the molding space flows into the groove before reaching the opening of the exhaust port. The side wall functions as a bank to prevent molding material from flowing out. Therefore, the exhaust port is not blocked by the molding material, and the air in the molding space and the gas contained in the molding material can be reliably expelled until the final stage of compression.

〔Example〕

The present invention will be explained below based on an embodiment shown in the drawings.

The mold for compression molding indicated by the reference numeral 1 in the figure is composed of an upper mold 2 which is a female mold and a lower mold 3 which is a male mold. It is connected to the ram of the machine and is moved up and down in the direction toward and away from the lower mold 3.

A recess 4 is formed on the lower surface 2a of the upper mold 2, and a protrusion 5 that fits into the recess 4 is formed on the upper surface 3a of the lower mold 3.
The inner surface of the concave portion 4 and the outer surface of the convex portion 5 are finished into smooth mold surfaces 4a and 5a, respectively. Then, a thermosetting resin or a molding material A made by kneading the thermosetting resin and a reinforcing material and molding it into a sheet or block shape is set on the top of this protrusion 5, and these recesses 4 A molding space 6 for compression molding the molding material A is provided between and the convex portion 5 .

A fitting step 7 that fits into the lower end opening of the recess 4 is formed on the outer circumference of the lower end of the protrusion 5. Between the fitting step 7 and the recess 4, there is a protrusion. 5 is fitted into the recess 4 and the mold 1 is closed, a minute gap 8 of, for example, about 0.1 to 0.4 aIm is formed that continues to the bottom of the molding @6.

Note that inside the upper mold 2 and the lower mold 3, there is a mold surface 4a.

A steam flow path 30 is formed to heat the molding material 5a to melt B and harden the molding material A.

Further, a ring-shaped introduction chamber 9 surrounding the outer periphery of the molding space 6 is formed between the upper mold 2 and the lower mold 3, and this introduction chamber 9 is formed between the fitting step 7 and the recess 8IS4. The molding space 6 is connected to the lower part of the molding space 6 through the space therebetween. A deeper mounting groove 10 is provided continuously in the circumferential direction on the outer circumference of the bottom surface of the introduction chamber 9, that is, on the upper surface 3a of the lower mold 3, and a seal ring 11 as a sealing member is provided in the mounting groove 10. , for example, by means of adhesive or the like in an airtight manner. The seal ring 11 of this embodiment is formed into a tube shape from a rubber material such as ethylene propylene rubber, and the seal ring 11 is made elastic by injecting liquid into its internal space 12 via a pump 13. Deformably expanded. In a free state where no compressive force is applied, this seal ring 11 protrudes upward from the upper surface 3a of the lower mold 3, and when the upper mold 2 descends, it comes into pressure contact with the lower surface 2a of the upper mold 2. The molding space 6 and the introduction chamber 9 are hermetically sealed from the outside.

Further, a pressure regulating valve 15 is provided in the pipe 14 connecting the internal space 12 of the seal ring 11 and the pump 13, and if the injection pressure of the fluid is adjusted by the pressure regulating valve 15, the injection pressure of the fluid can be adjusted. As shown by the lines, the seal ring 11 can be expanded to increase its outer diameter, or conversely can be deflated to decrease its outer diameter. Therefore, the timing at which the molding space 6 and the introduction chamber 9 become airtight can be freely changed depending on the thickness of the molding material A and the like.

Furthermore, since this seal ring 11 is pressurized from the inside, it is possible to prevent the upper mold 2 from becoming sagging due to any contact therewith. At the same time, since the seal ring 11 is cooled from the inside by injecting liquid, there is little thermal deterioration even though the entire mold 1 is heated by steam.
There is an advantage that the seal ring 11 has a long life.

On the other hand, a plurality of exhaust ports 17 are opened at intervals in the circumferential direction on the bottom surface of the recess 9, and these exhaust ports 1
7... are connected to an exhaust system M19 outside the mold 1 via an exhaust passage 18 formed inside the lower mold 3. As shown in FIG.
1, the booster pump 22, the first solenoid valve 23, the surge tank 24, and the second
A solenoid valve 25 is provided, and an exhaust valve 27 is provided in an exhaust branch pipe 26 branching from the downstream of the second solenoid valve 25. It is always evacuated by the rotary pump 20 and maintained in a vacuum state.

Note that the reference numeral 28 in the figure indicates a pressure relief valve.

Further, a groove 29 continuous in the circumferential direction is formed on the bottom surface of the introduction chamber 9, and is located inside the opening position of the exhaust port 11, that is, on the communication side with the molding space 6. .

This groove 29 is formed during molding through the gap 8 during the final stage of compression when the protrusion 5 fits into the recess 4. 6, and the bottom of this groove 29 is connected to the bottom of the exhaust port 17.
It is recessed than the opening of...

Next, the process of compression molding the molding material A will be explained.

First, as shown in FIG. 3, the upper mold 2 is raised to open the molding space 6, and the molding material A is set on the top of the convex portion 5.

Next, the press machine is operated to lower the upper mold 2. Then, the mold surface 4a of the upper mold 2 comes into contact with the molding material A, and the molding material A is pressed between the mold surfaces 4a and sa, forming a product as shown in FIG. 2, and filling the molding space 6. During molding @
It begins to flow towards the lower steel of 6.

As the compression progresses, when the lower surface 2a of the upper mold 2 comes into pressure contact with the seal ring 11, the introduction chamber 9 and the molding space 6
is hermetically sealed off from the outside, and in synchronization with this, the second solenoid valve 25 is opened, and the surge tank 24 is communicated with the molding space 6 and the introduction chamber 9. In this case, since the inside of the surge tank 24 is already in a vacuum state, the air in the molding space 6 and the introduction chamber 9 is sucked all at once through the exhaust ports 17, and the inside of the molding space 6 is Instantly transitions to low pressure space.

When the pressure in the molding space 6 becomes low as described above, the molding material A accompanied by air or gas flows from the entire lower circumference of the molding space 6 into the groove 2 at once due to the suction action from the exhaust ports 17.
The molding material A in a molten state flows into the groove 29 and stays in the groove 29, and most of the air and gas are separated during the inflow process and are transferred from the exhaust port 17 to the introduction chamber 9.
is discharged to the outside.

As the pressurization of the molding material A progresses, this molding material A is filled to every corner of the molding space 111B, and the excess material in the molding space 6 is poured into the gap 8 that continues to the lower part of the molding space 6. Flow into. This gap 8 is 0.1 to 0.4511
Since the amount of molding material A is minute, the excess molding material A becomes flaky and protrudes into the groove 29, and is eaten away by the gap 8. When the upper mold 2 is completely lowered and mold clamping is completed, the molding material A is densely filled into the molding space 6 and becomes pressurized, and the second electromagnetic valve 25 closes and the exhaust valve 27 closes accordingly. is opened, and the inside of the introduction chamber 9 returns to atmospheric pressure.

The pressurized molding material A is passed through the flow path 30 in each mold 2.3.
Because it is heated by the steam flowing through it, a polymerization reaction occurs within the molding space 6 and it hardens. The molded article B obtained by this curing is taken out by opening the mold 1 after a certain curing time has elapsed, thereby completing a series of compression molding.

According to such an embodiment of the present invention, a groove portion 29 located inside the opening device of the exhaust port 17 is provided on the bottom surface of the introduction chamber 9 connected to the molding space 6 over the entire circumference. Therefore, the molding material A with air and gas extruded from the lower part of the molding space 6 during the compression molding process flows into the groove 29 before reaching the opening of the exhaust port 17. The side walls of the groove 29 serve as banks that prevent the molding material A from flowing out, thereby preventing the molding material A from spreading within the introduction chamber 9.

Therefore, the exhaust port 17 is not blocked by the molding material A flowing into the introduction chamber 9, and the air in the molding space 6 and the gas in the molding material A are ensured until the final stage of compression. can be excluded. Therefore, during compression molding, there is no possibility that air bubbles that cause small pores or bulges will be trapped in the molding material A, and a high-quality molded product B with a smooth surface can be obtained.

In addition, in the above-mentioned embodiment, the seal member is a hollow seal ring, but the present invention is not limited to this, and may be, for example, a solid ring.

〔Effect of the invention〕

According to the present invention described in detail above, since the exhaust port is not blocked by the molding material, air in the molding space and gas in the molding material can be reliably expelled until the final stage of compression. Therefore, during compression molding, air bubbles that cause small pores and bulges are not trapped in the molding material, and a high-quality molded product with a smooth surface can be obtained.

[Brief explanation of the drawing]

The drawings show one embodiment of the present invention, and FIG. 1 shows the mold clamping completed.
FIG. 2 is a cross-sectional view of the molding space in an airtight state, and FIG. 3 is a cross-sectional view of the upper die starting to descend. 1...Mold, 2...Upper die, 3...Lower die, 4a,
5a...Mold surface, 6...Molding space, 9...Introduction chamber,
DESCRIPTION OF SYMBOLS 11... Seal member (seal ring), 11... Exhaust port, 19... Exhaust device, 29... Groove, A...
Molding material.

Claims (1)

[Claims] A molding space for compression molding a thermosetting resin molding material is formed between the upper mold and the lower mold, and a ring-shaped introduction chamber continuous to the lower part of this molding space, and this introduction chamber An exhaust port connected to the exhaust device is provided on the top surface of the lower mold, which is the bottom surface of the mold, and a sealing member is installed on either side of the mold to airtightly shut off the molding space and the introduction chamber until the final stage of compression. A mold for compression molding a thermosetting resin provided with a mold for compression molding a thermosetting resin, which is located on the bottom surface of the introduction chamber, and is located closer to the communication part with the molding space than the opening position of the exhaust port. A mold for compression molding thermosetting resin characterized by forming a concave ring-shaped groove.