JPS62134223A - Liquid resin sealing mechanism - Google Patents

Abstract

PURPOSE:To prevent the leakage of resin perfectly by a method wherein an annular surface, constituting a gap around a top force and a bottom force, is heated to a high temperature to harden thermosetting resin during a period in which the thermosetting resin moves to an opening at the outside opening. CONSTITUTION:A block 48 is fixed through an insulating material 44 along the whole periphery of the cavity surface 30 of a backup section 18 and a plate heater 54 is embedded in the block 48. When a top force 10 and a bottom force 12 are closed, a gap 52 is formed between an upper end face 50 and the annular surface 26 of the top force 10. When liquid thermosetting resin, curing agent or the like is poured into the cavity 14, the resin, entered into the gap 52, flows toward the outside of a molding mold, heated by the heated upper end face 50 and is hardened perfectly until it arrives at an opening at the outside of the gap 52 whereby the opening is blockaded so as to remain no gap. Accordingly, the leakage of the resin between the top force 10 and the bottom force 12 may be prevented. In this case, the resin cured in the gap 52 is removed as burrs after removing the cured resin from the mold together with the molded product.

Description

DETAILED DESCRIPTION OF THE INVENTION TECHNICAL FIELD The present invention relates to a sealing mechanism for preventing leakage of resin in a mold used for molding thermosetting resin.

BACKGROUND OF THE INVENTION A mold used for molding thermosetting resins such as unsaturated polyester, epoxy resin, and phenolic resin generally includes a first mold and a second mold that are closed together to form a cavity. In this type of mold, sealing has conventionally been performed in various ways in order to prevent the resin injected into the cavity from leaking from between the first mold and the second mold.

For example, a gap is formed between the mating surfaces of the first mold and the second mold around the cavity to allow air to escape but prevent resin from leaking. In FRP resin injection molding that strengthens the resin, the fiber base material sandwiched between the first mold and the second mold is larger than the cavity, and a rubber or metal pinch is placed in an annular shape between the mating surfaces of both molds. A member is arranged so that a portion of the fiber base material that is locally strongly compressed by the pinch member performs a sealing function. Furthermore, the circumference of the cavity is sealed with an O-ring or the like, and after the air inside the mold is removed using a vacuum pump or the like, resin is injected and the O-ring is used to prevent the resin from leaking.

Problems to be Solved by the Invention However, according to the first and second seal mechanisms, resin leakage cannot be completely prevented when the resin injection pressure is increased or when a resin with low viscosity is used. Therefore, during molding, it is necessary to use a resin with high viscosity or to lower the injection pressure of the resin, which makes it difficult to shorten the molding cycle, and due to resin leakage, the resin that should be filled into the cavity If the amount is insufficient, the molded product may be damaged, or
There was a problem in that cleaning had to be performed to remove resin leaked outside the mold, which increased the number of work steps.

According to the third sealing mechanism, resin will not leak even if the injection pressure is increased or a resin with low viscosity is used, but the molding cycle becomes longer due to the time required to bleed air from the cavity. Furthermore, if the air is not completely evacuated and accumulates in the corners of the cavity, there is a problem that the molded product may be damaged.

First Means for Solving the Problems The present invention has been made in order to solve the above problems, and the sealing mechanism according to the first invention has a seal mechanism between the first mold and the second mold. A gap is provided around the entire circumference of the cavity, with one end opening into the cavity and the other end opening outside, and at least one of the annular surfaces forming the gap between the first mold and the second mold. Along the entire circumference, the surface is heated to a temperature higher than that of the cavity, and
A heating element is embedded therein to heat the thermosetting resin injected into the cavity over a distance sufficient to cure the resin while it travels from the opening on the cavity side of the gap to the opening on the outside.

Effect of the first means According to the sealing mechanism according to the first invention, as the resin is injected, the air in the cavity is well discharged from the gap provided around the cavity, and then the resin flows into the gap. but,
By being rapidly heated by the surface of the gap that is heated to a higher temperature than the cavity, the resin hardens before it can travel to the outside opening of the mold, sealing that opening without any gaps and allowing the next inflowing resin to harden. It will function as a sealing material to prevent leakage.

Effect of the first means Therefore, even if the resin injection pressure is high or a resin with low viscosity is used, the hardened resin in the gap will perform a sealing function, and the injected resin will be removed from the mold. There is no risk of leakage, and the molding cycle can be shortened. In addition, by preventing resin leakage, there is no shortage of resin to be filled into the cavity, and a complete molded product can be obtained, and there is no need to remove resin leaked outside the mold. The effect of significantly reducing the number of work steps can be obtained.

Second Means for Solving the Problem Furthermore, the sealing mechanism according to the second invention has a porous elastic body sandwiched between the gaps of the sealing mechanism according to the first invention.

Effect of the second means Since the porous elastic body has sufficient air permeability for air circulation, the discharge of the air pushed out by the resin is not hindered, and the resin flowing into the gap is As in the sealing mechanism according to the first invention, it is heated and the flow is slowed down by the resistance provided by the porous elastic body.

Effect of the second means Therefore, according to the sealing mechanism according to the second invention, the effect of shortening the molding cycle can be obtained like the sealing mechanism according to the first invention, and when the heating temperature is the same, , since the rate of temperature rise relative to the distance traveled by the resin increases, the distance required for the resin to harden is shortened, and the size of the heating element and, by extension, the gap in the direction of resin movement can be reduced to make the mold more compact. At the same time, less resin flows into the gap, resulting in an effect of reducing molding costs.

EXAMPLES Hereinafter, examples of the first invention and the second invention will be described in detail based on the drawings.

What is shown in FIG. 1 is a mold equipped with a liquid resin sealing mechanism, which is an embodiment of the first invention, and this mold is used for molding products made of epoxy resin reinforced with glass fiber or the like. In the figure, 10 is an upper mold as a first mold, 12 is a lower mold as a second mold, and 4 these are the upper mold 10 and the lower mold 1.
2 is a bank up part 1 which together forms a cavity 14.
6.18, and an auxiliary plate 20.22 fixed to the back surface of the bank-up portions 16.18.

, a cavity 14 is provided in the backup part 1G of the upper die 10.
The cavity surface 24 and the annular surface 2 surrounding it
6, a plurality of pipes 28 are buried in parallel to each other, while a plurality of pipes 32 are buried in the backup part 18 only along the cavity surface 3° constituting the cavity 14.
are buried parallel to each other, and these pipes 28.32
By flowing oil into the cavity surface 24.3
0 is heated to 130°C. Further, a resin injection hole 34 extending in the vertical direction is formed in the upper mold 10, and a mixer 3 is inserted into this resin injection hole 34 during molding.
An injection gun 40 connected to a resin supply device (not shown) through a resin supplying device 6 is inserted, and resin is injected into the cavity 14 from a resin injection hole 42 of the upper mold 10.

As shown in FIGS. 1 and 2, a block 4 is fixed around the cavity surface 30 of the backup part 18 over the entire circumference with a heat insulating material 44 interposed therebetween. The block 48 is arranged so that its outer end surface exactly matches the side surface of the lower die 10 and its upper end protrudes from the cavity surface 30. Also, block 4
A plurality of spacers (not shown) are placed at appropriate intervals on the upper end surface 50 of the upper mold 8, and when the upper mold 10 and the lower mold 12 are closed, the upper end surface 5o and the annular surface 26 of the upper mold 10 are A gap 52 having a thickness of 0.2 mm is formed between them, with one end opening into the cavity 14 and the other end opening outside the mold.

A plate heater 54 as a heating body is embedded in the block 48, and this plate heater 54 has the following functions:
The upper end surface 50 of the block 48 can be heated to 250° C. by a temperature regulator (not shown). Further, the width of the block 48, that is, the length from the end on the cavity 24 side to the outer end is 200 mm. This length is long enough for the epoxy resin that has flowed into the gap 52 from the cavity 14 to be completely cured while being heated by the upper end surface 50 at 250° C. and moving from the opening on the side of the cavity 14 to the opening on the outside. It is.

During resin molding using the mold configured as above,
After the liquid thermosetting resin, curing agent, etc. supplied from the resin supply device are mixed in the mixer 36, the injection gun 40
The resin is injected into the cavity 14 through the resin injection hole 42, fills the gap in the fiber base material previously placed in the cavity 14, flows while eliminating air in the cavity 14, and flows into the gap 52. The resin that has flowed into the gap 52 flows toward the outside of the mold, but at this time, it is rapidly hardened by being heated by the upper end surface 50 heated to 250°C, and a pressure of about 30 kgf/cd is applied. Even if it is injected, it will completely harden by the time it reaches the opening on the outside of the mold in the gap 52, and the opening will be closed without any gap. This will prevent the resin from leaking between the two and 12.

Note that the resin that has hardened within the gap 52 is removed from the mold together with the molded product and then cut out.

FIG. 3 shows an embodiment of the second invention. In this example, the first
In a mold configured similarly to the mold shown in FIG. 2 and FIG.
A soft urethane foam material 60 of m is sandwiched therebetween.

The soft urethane foam material 60 is porous and can provide resistance to the resin flowing through the gap 52 while allowing air to be discharged. Therefore, the flow rate of the resin becomes slower and the rate of temperature rise relative to the moving distance increases, so the moving distance required for the resin to completely harden is shortened, and the width of the block 48 is shortened (150 mm in this example). )can do.

Further, in the gap 52, a material such as a glass fiber continuous strand cloak, which is a porous elastic organic or inorganic fiber base material impregnated with a reaction accelerator such as metaxylylene diamine, may be sandwiched. If you do that,
The curing of the resin is accelerated, the curing time is shortened, and the width of the block 48 can be made even shorter (for example, 120 mm).

In the above embodiments, the plate heater 54 serving as a heating element was buried only in the lower mold 12, but it was buried in the upper mold 10 or in the upper mold 10. It may be buried in any of the lower molds 12.

Furthermore, the heating body is not limited to the plate heater 54, but for example, the heating body may be a gap 52 of a pipe that heats the cavity 14.
It is also possible to heat the surface forming the gap 52 to a higher temperature than the cavity surface by using a pipe disposed along the gap 52.

Although not illustrated in detail, the present invention can be implemented with various modifications and improvements based on the knowledge of those skilled in the art.

[Brief explanation of drawings]

FIG. 1 is a front sectional view showing a mold equipped with a liquid resin sealing mechanism according to an embodiment of the first invention. FIG. 2 is a front sectional view showing the sealing mechanism. FIG. 3 is a front sectional view showing a liquid resin sealing mechanism which is an embodiment of the second invention. lO: Upper mold (first mold) 12: Lower mold (second mold) 14:
Cavity 48 Ni block 50: Upper end surface
52: Gap 54 Nibrate heater (heating body) 60: Soft urethane foam material (porous elastic body) Applicant: Todoroki Director, Agency of Industrial Science and Technology Figure 1 Figure 2 Figure 3

Claims (3)

[Claims] (1) In a thermosetting resin mold comprising a first mold and a second mold that are closed to each other to form a cavity, the liquid thermosetting resin injected into the cavity is mixed with the first mold. A sealing mechanism that prevents leakage from between the first mold and the second mold, the seal mechanism having one end opening into the cavity and the other end opening outside the first mold and the second mold. A gap is provided over the entire circumference of the cavity, and the temperature of at least one of the annular surfaces forming the gap between the first mold and the second mold is lower than that of the cavity. A heating element is embedded that heats the resin to a high temperature and over a distance sufficient to cure the thermosetting resin injected into the cavity as it moves from the opening on the cavity side of the gap to the opening on the outside. A liquid resin seal mechanism featuring: (2) In a thermosetting resin mold comprising a first mold and a second mold that are closed to each other to form a cavity, the liquid thermosetting resin injected into the cavity is connected to the first mold. A sealing mechanism that prevents leakage from between the first mold and the second mold, the seal mechanism having one end opening into the cavity and the other end opening outside the first mold and the second mold. A gap is provided around the entire circumference of the cavity, a porous elastic body is sandwiched in the gap, and at least one of the annular surfaces forming the gap between the first mold and the second mold is provided. The surface is heated to a temperature higher than the temperature of the cavity over the entire circumference, and the thermosetting resin injected into the cavity is cured while moving from the opening on the cavity side of the gap to the opening on the outside. A liquid resin seal mechanism characterized by having a heating element embedded therein that heats over a sufficient distance. (3) The liquid resin sealing mechanism according to claim 2, wherein the porous elastic body supports a reaction accelerator.