JP3530179B2 - Runnerless molding method for thermosetting resin and rubber - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION runnerless formed form how the invention such as a thermosetting resin and a rubber related.

[0002]

2. Description of the Related Art In this type of runnerless molding apparatus and method for thermosetting resin, rubber, etc., it is necessary to constantly maintain the sprue runner portion in a low temperature state of uncured and unvulcanized during molding operation. And is widely known (for example, see Patent Document 1, Patent Document 2, and Patent Document 3).

[0003]

[Patent Document 1] Japanese Utility Model Laid-Open No. 63-141714

[Patent Document 2] JP-A-11-129289

[Patent Document 3] Japanese Patent Laid-Open No. 2000-280293

[0004]

However, in these conventional examples, the structure for preventing the heat conduction to the runner portion having the flowable raw material at the molding temperature in the cavity as complicated as possible is sufficient and sufficient. There was a problem that the effect could not be expected.

The present invention has been made paying attention to the above points, and mainly forms a heat insulating space portion as a movable structure for advancing and retracting a runner portion having a fluid raw material with respect to a cavity during a molding operation. This prevents the high molding temperature of the cavity at the time of molding from being conducted to the runner part which is longer than the gate and is in the open / closed state, which eliminates the material loss of the sprue runner, and the secondary processing cost,
It is an object of the present invention to provide a molding method for thermosetting resin and rubber, which is designed to reduce industrial waste, improve moldability, and reduce the burden on the global environment.

[0006]

The present invention can solve the above-mentioned problems by providing the following constitutions.

[0007]

[0008]

[0009]

[0010]

[0011]

[0012]

[0013]

[0014]

[0015]

( 1 ) A runnerless molding method capable of continuously molding a raw material fluid such as a thermosetting resin and rubber in an uncured and unvulcanized state at a low temperature, in which a fluid is supplied. The raw material is supplied into the movable runner bush, and the movable runner bush is moved within the tubular temperature control bush. First, the movable runner bush is brought into contact with the gate of the cavity and the gate is opened. Immediately after pouring the fluid material into the cavity, advance the valve pin to the "gate closed" state, and keep the valve pin "gate closed" state and move the movable runner bush away from the gate side. , Forming an adiabatic space in the temperature control bush, and then heat-treating the inside of the cavity to cure or vulcanize it and take out the molded product, During the heat treatment or while taking out the molded product after the heat treatment, the valve pin is retracted to return to the initial state as the "gate open" state, and the repeated operation is performed again. Runnerless molding method for resin and rubber.

( 2 ) A valve pin that supplies the fluid material to be supplied to one or more movable runner bushes through a manifold, and is vertically passed through each movable runner bush, moves the valve pin shape and the valve pin forward and backward. To change the opening and closing timings of the gates to obtain the filling balance at the time of a multi-point gate freely, and the runnerless molding of thermosetting resin and rubber as described in ( 1 ) above. Method.

[0018]

BEST MODE FOR CARRYING OUT THE INVENTION An embodiment of the present invention will be described below with reference to the drawings.

In each drawing, reference numeral 1 denotes a cavity formed between a cavity plate 2 of one mold and a core plate 3 of the other mold not shown in detail in a chain line, 4
Is a gate opened to the cavity plate 2 side, 5 is an expanded circular hole portion having a conical bottom portion 6 drilled on the cavity plate 2 side with the gate 4 as the center, and 7 and 8 are polymerized and solidified on the cavity plate 2. The heat insulating plate to be installed and the first back plate are shown and communicate with each other in correspondence with the expanded circular hole portion 5 and are smaller than the diameter of the expanded circular hole portion 5.
0 is worn. Reference numeral 11 denotes a concave portion provided on the lower peripheral edge of the inner peripheral portion of the expanded circular hole portion 5 and exhibits a heat insulating action. The reference numeral 13 forms a gap 12 along the inner circumference of the expanded circular hole portion 5, so that the small holes 9 and 10 in the heat insulating plate 7 and the first back plate 8 are formed.
In the drawing, a temperature-regulating bush having a cylindrical hole shape is shown penetrating through, and the gap 12 forms an air gap with the cavity plate 2. Then, the head of the tubular hole-shaped temperature control bush 13 is
The temperature control bush 13 having a cylindrical hole shape is firmly fixed by being pressed by the surface of the first back plate 8. The tubular hole-shaped temperature control bush 13 is formed with a temperature control hole 14 whose outer cylindrical structure is constituted by an air gap in the space, and the first back plate 8 is formed in the temperature control hole 14. There is provided an opening 14a capable of communicating with a temperature control fluid, such as air or an inert gas, which communicates with the inside.

Reference numeral 15 designates a cylindrical movable runner bush slidably arranged in the tubular hole-shaped temperature control bush 13, and the tip of the cone-shaped head 1 coincides with the cone-shaped bottom portion 6.
5a is formed and a dish-shaped heat insulating bush 16 is provided on the conical head portion 15a so as to be located on the outer periphery of the gate 4 between the conical bottom portion 6 and the conical bottom portion 6 and independent of the air gap of the gap 12. The air gap 17 can be formed. Reference numeral 18 denotes a valve pin arranged in the central axis direction of the movable runner bush 15, and the central hole 1 of the movable runner bush 15 and the dish-shaped heat insulating bush 16 is shown.
The gate 4 can be opened and closed through 9 and 20.

Reference numeral 21 denotes a runner portion formed in the movable runner bush 15 and the stopper rod 38 where the pouring fluid material stays, and the opening 37 of the stopper rod 38 to which the base of the movable runner bush 15 is fixed. Through the manifold 2
It is in communication with the second runner portion 23. Although the pressing rod 38 is formed separately from the movable runner bush 15 in the drawing, it may be formed as an integral structure. In this case, it goes without saying that the opening 37 is provided in the movable runner bush 15 which is integrated.

Reference numeral 24 denotes a runner sliding mechanism for moving the movable runner bush 15 forward and backward, for example, a piston cylinder mechanism, which is arranged on the first back plate 8 via a first spacer block 25. The cylinder portion 24a is fixed to the second back plate 26, the tip of the piston portion 24b is fixed to the manifold 22, and the movable runner bush 15 is movable via the manifold 22.

Reference numeral 27 denotes a valve sliding mechanism for moving the valve pin 18 forward and backward, for example, a piston cylinder mechanism, which is fixed above the second back plate 26 via a second spacer block 28. The cylinder portion 27a is fixed to the side mounting plate 29, the tip end of the piston 27b is fixed to the base portion of the valve pin 18, and is fixed to the valve pin operating plate 30 which is disposed on the second back plate 26 and is separable. The valve pin 18 is movable via 30.

Reference numeral 31 denotes a nozzle for injecting the raw material, which is disposed on the fixed side mounting plate 29, and communicates with this injection nozzle 31.
In addition, it is connected to the runner portion 23 of the manifold 22 provided with the movable injection hole portion 32 having a slidable structure.

In the figure, the structure of two molded products in which the cavity 1 is formed at two positions is shown. However, the structure of a single unit having one cavity 1 as well as a larger number of molded products is shown. Can also be implemented.

Further, although only the structure in which one movable runner bush 15 is disposed in the temperature control bush 13 is shown, the cross-sectional structure of one temperature control bush 13 is enlarged to provide a plurality of holes (gap 12). (Corresponding to the expanded circular hole portion 5 and the small holes 9 and 10) forming a plurality of movable runner bushes may be arranged in parallel in the hole.

Reference numeral 33 is a temperature adjusting hole formed in the cavity plate 2, the first and second back plates 8 and 26, and the manifold 22 in a large number, and together with the temperature adjusting hole 14, the flowable raw material for molding is in the cavity 1. Water, oil or gas flow holes that are circulated before heat treatment so as not to be heat-cured are shown. Reference numeral 34 designates a heating means such as a heater or other heating medium arranged on the cavity plate 2 for heating and hardening the fluid material filled in the cavity 1. Reference numeral 35 denotes a sprue bush forming the injection nozzle 31, and 36 denotes a locate ring arranged on the outer periphery of the sprue bush 35, so that the nozzle of each raw material outflow molding machine is brought into close contact with the injection nozzle 31 accurately and airtightly. Shows a positioning ring for.

Based on the above configuration, FIG.
The function of the present invention, that is, the molding method will be described with reference to (b), (c) and (d).

The raw material of a specific thermosetting resin or rubber is previously uncured or unvulcanized, that is, in the state of a fluid raw material, from the injection nozzle 31 through the runner portion 23 of the manifold 22 and the runner portion 21 of the movable runner bush 15. It is placed in the inside of the movable runner bush 15 and is retained in the state of FIG.
The center holes 19 and 20 at the tip of the are held and placed.

That is, the runner piston cylinder mechanism 24 and the valve piston cylinder mechanism 27 are held in an inoperable state, the movable side core plate 3 shown by the chain line is retracted, and the cavity 1 is opened. Leave it unformed.

Next, the core plate 3 advances toward and abuts on the fixed cavity plate 2 side to form the cavity 1, and at the same time, the runner piston cylinder mechanism 2 is formed.
4, the piston portion 24b moves forward, the movable runner bush 15 fixed to the manifold 22 slides forward in the temperature control bush 13 in the shape of a cylindrical hole, and the conical head portion 15a at the tip end becomes a dish shape. Via the adiabatic bush 16 of the above, it abuts on the conical bottom portion 6, thereby forming an air gap 17, and the center hole 19 of the movable runner bush 15 is
The dish-shaped heat insulating bush 16 is communicated with the gate 4 of the cavity 1 through the central hole 20 (see FIG. 3B).

The air gap 17 is shown in the figure.
Can be formed between the conical bottom portion 6 and the conical head portion 15a, but the concavity is formed not on the conical bottom portion 6 side but on the conical head portion 15a side. Even if it does, the air gap 17 can be similarly formed (not shown).

In this state, the valve pin 18 is connected to the gate 4
Since it is not inserted into the inside, it is in the state of " gate open", and it is possible to inject the fluid raw material, so that the pouring of various molding machines for pouring raw material (not shown) connected to the injection nozzle 31 By obtaining the operating force, the fluid raw material can be made to inject the staying raw material in the runner portion 23 of the manifold 22 and the runner portion 21 of the movable runner bush 15 into the required amount cavity 1 from the gate 4.

At the same time when the injection of the fluid material into the cavity 1 is completed, the valve piston cylinder mechanism 2
7, the piston portion 27b moves forward, the valve pin 18 also moves forward via the valve pin operating plate 30, and the tip portion passes through the center hole 19 of the movable runner bush 15 and the center hole 20 of the dish-shaped heat insulating bush 16 to the gate. 4 and the opening of the gate 4 is closed so that the so-called “ gate closed” state shown in FIG. 3C can be obtained.

Then, immediately the movable runner bush 15
The piston portion 24b retracts by the action of the runner piston cylinder mechanism 24, retracts in the tubular hole-shaped temperature control bush 13, and retracts to a position sufficiently separated from the gate 4 as shown in FIG. 3 (d). In addition to this, a space portion, that is, a heat insulating space portion A can be formed between the tip of the movable runner bush 15 in the tubular hole-shaped temperature control bush 13.

In this state, the uncured resin or uncured resin filled in the cavity 1 is heated by a heating means 34 such as a heater for heat treatment for curing and molding, and the thermoformed molded article is The movable side core plate 3 can be moved to be separated from the fixed side cavity plate 2, and the molded product of the cavity 1 can be taken out by a usual method. It should be noted that the valve pin 18 is retracted by the operation of the valve piston cylinder mechanism 27 at a desired timing during the time from the curing start time of the uncured resin or the unvulcanized resin to the time of reaching the complete curing, and as a whole, FIG. It is possible to return to the state of.

Since the first molding operation is completed as described above,
After that, by repeating the same operation and repeating the same operation, the same molded product can be produced in mass production.

The embodiment of the present invention has been described above.
Next, another embodiment in which the configurations of the sliding mechanism for the runner portion and the sliding mechanism for the valve differ from the first embodiment will be described with reference to FIGS. 4 and 5 (a) (b) (c) and (D) will be described.

In the figure, the same reference numerals as those in the first embodiment indicate the same components, and the detailed description thereof will be omitted.

That is, in the second embodiment, the tip end of the piston 27b of the piston cylinder mechanism 27 corresponding to the valve sliding mechanism is fixed on the central axis of the piston cinder mechanism 24 corresponding to the runner sliding mechanism. The valve pin 18 is slidably inserted, and the cylinder portion 24a and the piston portion 24b of the runner piston cylinder mechanism 24 are arranged on a cylinder plate 26A instead of the second back plate 26.
The cylinder portion 27a and the piston portion 24b of the valve piston cylinder mechanism 27 described above are arranged on the fixed side attachment plate 29 adjacent to.

The piston portion 24b of the runner piston cylinder mechanism 24 is a movable runner bush 15
It is directly connected to the base portion of A and the insertion slide tube portion 39 of the valve pin 18 is arranged on the shaft.

The opening 37 which connects the runner portion 21 of the movable runner bush 15A and the runner portion 23 of the manifold 22 communicates with the raw material in the uncured or unvulcanized state by the sliding action of the movable runner bush 15A. When it is always possible to make the movable runner bush 15A long, the movable runner bush 15A can be formed to have a long opening in any sliding position. 37, the runner portion 23 of the manifold 22 and the runner portion 2 of the movable runner bush 15A.
The state of being communicated with 1 can be maintained (not shown).

Under the above-mentioned structure, the injection molding process in the uncured and unvulcanized state of the thermosetting resin and rubber is shown in FIGS. 3 (a) (b) (c) and (d) of the first embodiment. 5 (a) (b) (c) are shown corresponding to the injection molding process of FIG.
And (d), and details of the process of the molding operation are the same as those in FIGS. 3 (a), (b), (c) and (d).

Therefore, in brief, the uncured and unvulcanized fluidized raw material moves from the operating position shown in FIG. 5 (a) showing the preparation for molding to the operating position shown in FIG. 5 (b) where the injection molding is started. 5 (c) through the operation position of injection completion, and FIG.
The operation position for heat curing and vulcanization molding of “gate closed” in (d) is reached, the operation of taking out the molded product by retreating the valve pin 18 is completed, and the operation position shown in FIG.
The first molding step is completed.

During the molding process, the opening portion 37 of the movable runner bush 15A is displaced from the runner portion 23 of the manifold 22 in a non-circulating state at the sliding position shown in FIGS. 5 (a) and 5 (d).

Next, another different embodiment of the present invention will be described.

In all of the above embodiments, the movable runner bush is shown as a structure that slides in the temperature control bush, but this temperature control bush is omitted and the movable runner bush itself has this temperature control function. By providing the above, it is possible to carry out a completely similar molding apparatus and molding method.

A representative example thereof is shown in an enlarged cross section in FIG.

The movable runner bush 15B having the valve pin 18 slidably passed through is provided with a runner portion 21 on the center of which the valve pin 18 can slide.
A hollow temperature control space 40 is formed along the outer periphery of the movable runner by supplying a desired fluid such as water, oil, air, or an inert gas as a temperature control medium into the temperature control space 40. The flow material such as thermosetting resin and unvulcanized rubber flowing in the bush 15B is prevented from being hardened by the heat transmitted from the mold, and the temperature of the flow material is prevented from dropping, so that an accurate temperature is always maintained. It is created so that it can be controlled so that the state can be maintained.

Therefore, this movable runner bush 1
5B, the base portion is fixed to the manifold 22 similarly to the configuration shown in the above-mentioned embodiment, and the temperature control fluid is disposed in the manifold 22 and the temperature control space portion 4 through the opening 40a.
0, and the movable runner bush 15B main body may be movably arranged in a through hole 41 penetrating the cavity plate 2, the heat insulating plate 7, the first back plate 8 and the like which compose the mold. It does not matter if it is slid also with respect to the hole 41 or is moved back and forth through the gap without sliding.

According to this structure, the movable runner bush 15B can always control the temperature during operation, and the movable runner bush 15B itself exhibits the same operation as that of the above-mentioned embodiment, and the detailed description thereof will be repeated. I will omit it because it does.

By the way, in the above-mentioned embodiments, all of them relate to multi-cavity multi-cavity multi-cavity multi-cavity multi-cavity multi-cavity production. One cavity can be targeted. In this case, by changing the shape of each valve pin and the timing of opening and closing the valve pin with respect to the gate by each piston cylinder mechanism that operates the valve pin, it is possible to make the filling balance at the multipoint gate flexible. it can.

Further, since an opening / closing system using a valve pin is provided as an embodiment, the gate diameter can be set from a small diameter to a large diameter according to the size and shape of the gate, and in the case of a large diameter, filling is performed. The pressure can be reduced and labor can be saved, the internal pressure can be reduced accordingly, which leads to the reduction of product stress and helps to eliminate product defects. Furthermore, the filling time can be shortened, that is, the injection rate of injection molding can be increased.

In any of the embodiments, the structural device can be arranged not only in the vertical structure as shown in the drawing but also in the lateral direction in the left and right directions.

Examples of the thermosetting resin which can be used in the present invention include urea resin, phenol resin, melamine resin, furan resin, alkyd resin, unsaturated polyester resin, diallyl phthalate resin, epoxy resin, silicon resin, Polyurethane resin and the like can be used, and as the rubber material, styrene-butadiene rubber, ethylene-propylene rubber, ethylene-propylene ter-polymer and other butadiene rubber, high styrene rubber, isoprene rubber, butyl rubber, halogenated butyl rubber, villin rubber, All materials such as chlorinated polyethylene and ethylene-acrylic rubber can be used.

[0056]

According to the present invention, when the flowable raw material such as thermosetting synthetic resin or rubber filled in the cavity is heated to the curing temperature or the heating temperature, the movable runner bush is separated from the gate of the cavity. The uncured or unvulcanized fluid resin is movably retracted to a position to form a heat insulating space, and the temperature control effect of various fluids flowing through the temperature control holes provided in each part on the fixed side and the heat insulation effect of the air gap. The high temperature heating of the cavity to the runner portion that has accumulated is insulated so that the runner portion is not carelessly heated and the fluid resin inside is not heat-cured or vulcanized, and the gate of the cavity is opened and closed. By opening and closing the valve pin along the center axis of the movable runner bush, the gate can be opened and closed properly and reliably to prevent drawing from the gate. It can, be unnecessarily the product secondary processing such gate mark treatment, and can completely prevent the derivation of sprue runner.

Therefore, it is possible to eliminate sprue runners that have conventionally been generated in molding processes such as thermosetting resin, rubber injection, compression and transfer, and to prevent material loss and
Secondary processing costs and reduction of industrial waste can be obtained, and material costs and
It has the effects of improving the economic efficiency of processing costs and industrial waste processing costs and reducing the burden on the global environment.

[Brief description of drawings]

FIG. 1 is a longitudinal sectional view showing an embodiment of a runnerless molding apparatus for thermosetting resin, rubber, etc. according to the present invention.

FIG. 2 is an enlarged cross-sectional view of the main part of FIG.

FIG. 3 (a) is a vertical sectional view showing a sequential molding process.

FIG. 3B is a vertical cross-sectional view showing a sequential molding process.

FIG. 3C is a vertical sectional view showing a sequential molding process.

FIG. 3D is a vertical sectional view showing a sequential molding process.

FIG. 4 is a vertical cross-sectional view of a main part showing another embodiment.

FIG. 5A is a vertical cross-sectional view of a sequential molding process.

FIG. 5B is a vertical cross-sectional view of a sequential molding process.

FIG. 5C is a vertical cross-sectional view of a sequential molding process.

FIG. 5D is a vertical cross-sectional view of a sequential molding process.

FIG. 6 is an enlarged sectional view showing another embodiment of the movable runner bush.

[Explanation of symbols]

1 Cavity 4 Gate 13 Temperature Control Bush 14 Air Gap Temperature Control Holes 15, 15A, 15B Movable Runner Bush 18 Valve Pins 21, 23 Runner 22 Manifold 24 Runner Sliding Mechanism For example, Piston Cylinder Mechanism 27 Valve Sliding Mechanism For example, piston cylinder mechanism 31 material injection nozzle 37 opening 40 temperature control space A heat insulation space

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Claims (2)

(57) [Claims] 1. A runnerless molding method capable of continuously molding a raw material fluid such as a thermosetting resin and rubber in an uncured and unvulcanized state at a low temperature, in which a fluid material to be supplied is supplied. Is supplied to the movable runner bush, and the movable runner bush is movably moved in the tubular temperature control bush, and first comes into contact with the gate of the cavity to flow in the movable runner bush in the "gate open" state. Immediately after pouring the raw material into the cavity, move the valve pin forward to bring it to the "gate closed" state, and at the same time hold the valve pin in the "gate closed" state, separate the movable runner bush from the gate side, A heat insulating space is formed inside the temperature control bush, and then the inside of the cavity is heat treated and molded by curing or vulcanization, and the molded product is taken out. Open the gate by retracting the valve pin while removing the molded product during or after heat treatment.
In the runnerless molding method for thermosetting resin and rubber, the method is performed by returning to the initial state and repeating the operation again. 2. A valve pin, which supplies the fluid material to be supplied to one or more movable runner bushes through a manifold, and is vertically passed through each movable runner bush, in order to advance and retract the valve pin shape and the valve pin. The runnerless molding method for a thermosetting resin and rubber according to claim 1, wherein the opening and closing timings with respect to the gate are changed respectively so that the filling balance at the multipoint gate can be freely obtained.