JP3227199U6 - Screw injection device and injection molding device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To produce a micro foam molded product having high strength and light weight, which does not contain coarse bubbles due to moisture or residual monomer in a screw injection device.
SOLUTION: A screw injection device 10 has a vent hole 11a for discharging steam from the inside of a plasticizing cylinder 11 and a reinforcing material supply hole 11b for supplying a predetermined reinforcing material into the cylinder. A supercritical fluid supply hole 11c for supplying a predetermined supercritical fluid into the cylinder is formed on the tip side of these holes.
[Selection diagram] Fig. 1

Description

The present invention relates to a screw injection device and an improvement of an injection molding device configured by using the screw injection device.

Conventionally, a fine foam molding method using a supercritical fluid of a foaming gas is known as a technique for reducing the weight of an injection molded product. By using this method, a lightweight molded product can be obtained by containing a large number of fine foams inside. However, the molded product thus obtained tends to have weaker strength than the conventional molded product without fine foaming.

On the other hand, in the following patent document, for example, a resin composition in which reinforcing fibers are kneaded in advance is used, and a supercritical fluid of a foaming gas is injected into the resin and then molded to form the reinforcing fibers. It is described that a fine foam molded product showing superior impact resistance as compared with a conventional molded product that does not contain the above can be obtained.

Japanese Unexamined Patent Publication No. 2012-192630

By the way, if the resin before molding contains water or volatile residual monomers, bubbles may be generated in the molded product. In particular, in the case of fine foam molding, if coarse bubbles are generated due to moisture or residual monomer, the strength is significantly reduced at that portion, which is a problem. Conventionally, as a countermeasure against such a problem, it has been common to dry the resin pellets in advance. However, the moisture and residual monomers contained in the resin could not be completely removed only by drying, and the moisture and residual monomers adversely affected the strength of the fine foam molded product.

The present invention was made by paying attention to this problem, and by reliably removing water and residual monomers and injecting a resin containing a reinforcing fiber and a foaming gas, a high-strength and lightweight microfoam molding is performed. It is an object of the present invention to provide a screw injection device capable of manufacturing a product and an injection molding device using the screw injection device.

The screw injection device according to the present invention has a plasticized cylinder in which a screw is inserted, and the plasticized cylinder has a vent hole for discharging steam from the inside of the cylinder in the middle portion thereof, and a predetermined reinforcing material in the cylinder. It is characterized in that a reinforcing material supply hole for supplying the material is formed, and a supercritical fluid supply hole for supplying a predetermined supercritical fluid is formed in the cylinder on the tip side of the hole. To do.

Further, the injection molding apparatus according to the present invention is formed by combining the screw injection apparatus with a molding die.

In the present invention, impurities such as water and residual monomers are removed from the plasticized resin by venting, and the resin is supplied with reinforcing fibers and foaming gas as a supercritical fluid. It does not contain coarse bubbles due to residual monomers, and can produce high-strength and lightweight microfoam molded products.

It is a vertical cross-sectional view which shows the schematic structure of an example of Embodiment. It is a phase diagram regarding the temperature and pressure of a general substance. It is a vertical cross-sectional view which shows the schematic structure of the modification of the embodiment. It is a vertical sectional view which shows the schematic structure of the other modification of the embodiment. It is a vertical sectional view which shows the schematic structure of the further modification of the embodiment. It is a vertical sectional view which shows the schematic structure of the further modification of the embodiment. (A) to (e) are a side view, a vertical cross-sectional view, a cross-sectional view when the front end side is viewed, a cross-sectional view when the rear side is viewed, and a vertical sectional view of a specific example of the tip device mounted on the screw. It is a front view of the valve body housed in the tip device. (A) and (b) are side views of a specific example of a tip device for explaining a state when the valve body moves back and forth. (A) is a side view of another example of the advanced device, and (b) and (c) are cross-sectional views illustrating the operation of the advanced device. It is a vertical cross-sectional view which shows the schematic structure of the injection molding apparatus by this invention. (A) to (d) are a series of cross-sectional views for explaining the operation of the injection molding apparatus in chronological order. (A) is a simple cross-sectional view for explaining the progress mode of the resin in the mold, and (b) is a simple cross-sectional view of the solidified work.

FIG. 1 is a vertical cross-sectional view showing a schematic configuration of an injection device as an example of an embodiment.
As will be described in detail below, the injection device 10 removes impurities such as water and residual monomers from the plasticized resin by venting, and the resin contains reinforcing fibers (reinforcing material) F and a supercritical fluid. Since the foaming gas S is supplied, it is possible to produce a high-strength and lightweight microfoam molded product that does not contain coarse bubbles due to moisture or residual monomers.
As the resin, PLA (polylactic acid), PA (polyamide), PET (polyethylene terephthalate), PP (polypropylene) and the like are suitable, but the resin is not limited thereto.

The injection device 10 is an in-line screw type and has a plasticized cylinder 11 in which the screw 12 is inserted.

The cylinder 11 is a cylinder made of magnetic metal, for example, ordinary steel, and an injection nozzle 13 is provided at the tip thereof, and the rear end is opened to extend the screw 12 rearward. Further, the cylinder 11 has a vent hole 11a for discharging moisture and residual monomer vapor from the inside of the cylinder 11 and a reinforcing material supply hole 11b for supplying a predetermined reinforcing fiber F into the cylinder 11 in the middle portion thereof. Further, a supercritical fluid supply hole 11c for supplying the supercritical fluid S of the foaming gas is formed in the cylinder 11 on the tip side of these holes. A resin pellet supply hole 11d for supplying the resin pellet PP into the cylinder 11 is formed at the rear end of the cylinder 11, and a hopper 14 for storing the resin pellet PP is provided above the resin pellet supply hole 11d. ..

An induction heating coil 15 is wound around the peripheral wall surface of the cylinder 11. The power supply device and the like for supplying an alternating current to the coil 15 are not shown. The heat insulating material 16 is arranged in a tubular shape so as to cover the coil winding portion of the cylinder 11. The type of the heat insulating material 16 is not particularly limited.
Briefly explaining the induction heating of the cylinder 11, an alternating current is passed through the coil 15 to generate an alternating magnetic field in the axial direction of the cylinder 11. Since the cylinder 11 is made of a magnetic metal exhibiting high magnetic permeability, most of its magnetic field passes through the wall surface of the cylinder 11. Then, an eddy current is induced in the wall surface of the cylinder 11 in the direction of canceling the change of the magnetic field, that is, in the circumferential direction. The cylinder 11 is heated by the Joule heat generated by this eddy current. If such induction heating is used, the heating device of the cylinder 11 becomes compact and the efficiency becomes high.

The injection nozzle 13 is a shut-off type, is formed in a substantially conical shape so as to automatically align with the nozzle receiving portion of the molding die, and a resin injection port 13a is opened at the tip thereof. Opening and closing can be controlled by the valve mechanism 13b.

The screw 12 is a rod body made of ordinary steel or various alloys, and a series of spiral grooves are formed over substantially the entire length except for the tip portion. By making the shaft diameter or the groove shape of the screw 12 different for each part, the supply region 12b, the measuring region 12c, the vent region 12d, and the mixing region 12e are separately set in order from the rear end to the tip. The volume per pitch of the measuring region 12c is set so that the resin feed amount per rotation of the screw 12 becomes a predetermined value. The volume per pitch of the supply region 12b and the vent region 12d is set to be larger than that of the measurement region 12c. In the mixing region 12e, protrusions, ridges, etc. having a special shape are regularly arranged, and the reinforcing fibers F and the supercritical fluid S supplied in the cylinder 11 are uniformly mixed with the resin P. ing.

When the screw 12 is rotated with an alternating current flowing through the coil 15, the resin pellet PP that has fallen from the hopper 14 to the supply region 12b in the cylinder 11 is transported to the tip side of the cylinder 11 and pressurized in the measuring region 12c. , Is plasticized. The plasticized resin P is temporarily decompressed in the vent region 12d. Therefore, if the vent hole 11a and the reinforcing material supply hole 11b are arranged in the decompressed vent region 12d, the resin ejection phenomenon (vent-up phenomenon) can be suppressed. Since the plasticized resin P has a high temperature, moisture and vapors of residual monomers are easily released from the vent hole 11a opened to the outside, and as a result, the resin P has moisture and moisture on the tip side of the vent hole 11a. It becomes a high-purity product in which residual monomers are almost completely removed. After that, the resin P is mixed with the reinforcing fiber F from the reinforcing material supply hole 11b, and the supercritical fluid S is further injected from the supercritical fluid supply hole 11c. In the mixed region 12e, these reinforcing fibers F and the supercritical fluid S are injected. Is kneaded into the resin P.

The rear end of the screw 12 is connected to the motor device 18 through the power cylinder device 17. Here, the motor device 18 is a power source for rotating the screw 12, and the power cylinder device 17 is a power source for moving the screw 12 back and forth.

The power cylinder device 17 is composed of a hydraulic cylinder, an electric cylinder, and the like. Here, the basic structure of a hydraulic cylinder is shown as an example. The screw 12 is moved back and forth by adjusting the hydraulic pressure applied to the illustrated chambers A and B. When the screw 12 advances, the resin P accumulated at the tip of the cylinder 11 is ejected from the injection nozzle 13.

On the other hand, the motor device 18 is composed of a motor unit such as a stepping motor, a brush motor, and a brushless motor, and a power transmission mechanism and the like. When the motor device 18 rotates the screw 12, the resin pellet PP or the plasticized resin P is transported toward the tip of the cylinder 11 by the action of the spiral groove.

The reinforcing material supply device 20 is an element that supplies the reinforcing fiber F to be kneaded to the resin P. The reinforcing fiber F supplied to the reinforcing material supply hole 11b of the cylinder 11 is mixed with the resin P and automatically drawn into the cylinder 11. Therefore, the reinforcing material supply device 20 can be easily configured by, for example, a reel holding portion for supplying the reinforcing fiber F, a fiber thread feed guide, and the like as shown in the figure.

As the reinforcing fiber F, carbon fiber filament yarn (long fiber), carbon fiber tow (a bundle of thousands to tens of thousands of filaments) and the like are suitable, but the present invention is not limited thereto. For example, a glass fiber filament may be used as another reinforcing fiber, or a carbon fiber filament and a glass fiber filament may be mixed and used. Further, chopped fiber in which the fiber toe is cut to a predetermined length in advance may be used.

The reinforcing material is not limited to a fibrous material, and a granular material can also be used. For example, carbon, ceramic, glass powder and the like. It is considered that the fibrous reinforcing material mainly contributes to the tensile strength of the molded product, and the granular reinforcing material contributes to the compressive strength of the molded product.

The reinforcing fiber F supplied into the cylinder is shredded to an appropriate length by the screw 12 at the vent region 12d. The shredded reinforcing fibers F are uniformly dispersed in the resin P by mixing in the mixing region 12e.

The supercritical fluid supply device 21 is an element that pressurizes a foaming gas such as nitrogen and carbon dioxide and sends it out as a supercritical fluid S at a constant flow rate, and is composed of a tank, a heater, a pressurizing pump, a solenoid valve, and the like. To.

The supercritical fluid injection device 22 is an element that receives the supercritical fluid S from the supercritical fluid supply device 21, adjusts the pressure of the fluid, and quantitatively injects the supercritical fluid S into the cylinder 11 from the supercritical fluid supply hole 11c. , Pressure sensor, electromagnetic valve, etc.

FIG. 2 is a phase diagram relating to the temperature and pressure of a general substance. As shown in this phase diagram G, the substance has three phases of solid, liquid, and gas. Normally, when a gas is compressed, it becomes a liquid at a certain pressure. However, if the temperature exceeds a certain value at this time, it will not become a liquid no matter how much pressure is applied. Such a value is called the critical temperature of the substance. In addition, when a liquid is heated, it usually becomes a gas at a certain temperature. However, if the pressure exceeds a certain value at this time, it will not become a gas no matter how much it is heated. Such a value is called the critical pressure of the substance.
When both the temperature and pressure of a substance exceed the critical temperature and the critical pressure, the substance is a fluid in which a gas and a liquid cannot be distinguished, that is, a supercritical fluid. Supercritical fluids are known to exhibit both high diffusivity of gases and high solubility of liquids.

The reason why the foaming gas is made into a supercritical fluid and injected into the cylinder is that it is necessary to increase the pressure to inject a large amount of gas, resulting in a supercritical fluid, and the fluid is weighed more than the gas. Is easy. Further, if the foaming gas is injected into the cylinder in the state of a supercritical fluid, it is considered that the diffusibility immediately after the injection is also improved.
The solubility of the effervescent gas in the resin increases with the pressure of the resin, but the supercritical fluid injection device controls the injection amount of the effervescent gas so that the injection amount is slightly lower than the saturation amount. Then, by sufficiently mixing the resin in which the foaming gas is injected, a single-phase resin in which bubbles of the foaming gas are not mixed can be obtained. Further, this mixing appropriately cuts the reinforcing material and disperses it well in the resin. When such a resin is injected into a mold, the solubility of the foaming gas drops sharply due to the decompression in the mold, the foaming gas evaporates, and a large number of minute bubbles are generated in the resin.
Further, after the resin is injected into the molding die, it spreads to the cavity or the like due to the injection pressure. However, since the resin in which a large number of minute bubbles are generated becomes soft due to the decrease in viscosity, the injection pressure can be lowered. If the injection pressure is low, the pressure that the molding die receives from the resin is also small, so that the mold clamping force can be small and the press device can be miniaturized. For example, in the case of a resin pallet having an area of about 0.5 to 1 square meter, a mold clamping force of about 700 to 3000 tons has been conventionally required, but this can be reduced to about 450 to 1000 tons. Further, since the decrease in the strength of the molded product due to the micro-foaming of the resin is compensated for by blending the reinforcing fibers, it is possible to reduce the weight by about 10% to 10% while maintaining the strength of the molded product.

Further, in the present embodiment, since water and residual monomers are removed from the resin by venting, it is not necessary to dry the resin pellets in advance, and coarse bubbles due to water and residual monomers are not generated in the molded product. The decrease in strength of the resin is also suppressed.

FIG. 3 is a vertical cross-sectional view showing a schematic configuration of a modified example of the embodiment.
The major difference between this modification and the embodiment shown in FIG. 1 is that a reinforcing material supply amount adjusting device 23 that freely adjusts the supply amount of the reinforcing fiber F is provided.

The reinforcing material supply amount adjusting device 23 may be configured by combining a driving roller whose rotation speed can be adjusted and a driven roller facing the driving roller. In such a case, if the rotation speed of the drive roller is adjusted with the reinforcing fiber F sandwiched between the drive roller and the driven roller, the supply amount of the reinforcing fiber F changes according to the rotation speed. By providing such a reinforcing material supply amount adjusting device 23, for example, it becomes possible to supply a larger amount or a smaller amount of reinforcing fiber F than automatically drawn into the cylinder 11, and the strength of the molded product is increased. Can be adjusted freely. Further, the reinforcing material supply amount adjusting device 23 may adjust the number of filament yarns (toe). Further, the reinforcing material supply amount adjusting device 23 may include a cutting means for automatically cutting the reinforcing fiber F to an appropriate length, so that the reinforcing fiber F having a constant length is always supplied to the reinforcing material supply hole 11b. (Not shown).

Further, in this modification, the vent hole 11a and the resin supply hole are formed as one common hole. If the vent hole 11a and the resin supply hole are formed as one common hole, there is an advantage that the manufacturing cost of the cylinder 11 can be suppressed.
Since the other elements are common to the above-described embodiment, the common elements are designated by the same reference numerals and the description thereof will be omitted.

FIG. 3A is a vertical sectional view showing a schematic configuration of another modification of the embodiment. The same reference numerals are given to the elements common to the above-described embodiments, and the description thereof will be omitted.
The major difference between this modification and the embodiment is that a heat treatment device 24 for energizing the reinforcing fiber F before being supplied to the reinforcing material supply hole 11b to generate heat is further provided, and further, the heat treatment device 24 processes the heat treatment. A surface treatment device 25 for applying a predetermined surface treatment to the reinforcing fiber F after the heat treatment is provided.

The reinforcing fiber F is assumed to be a carbon fiber filament yarn or a tow. Filament yarn is a fiber bundle in which a large number of single fibers having a thickness of 5 to 10 μm are converged, and tow is a fiber bundle in which thousands to tens of thousands of filament yarns are further converged. These filament yarns and towes are coated with resins such as epoxy-based, urethane-based, and polyamide-based as a converging agent for suppressing fraying of fiber bundles.

The reinforcing fiber F in the present invention is intended to reinforce a molded product, but what is important for that purpose is workability and dispersibility during injection molding and adhesion to the resin after curing. Strength (drag against pulling out from resin). Generally, the resin (matrix) and the converging agent are compatible with each other, and if the compatibility is poor, even if the reinforcing fiber F is kneaded, good dispersion and strong adhesion to the resin are not achieved, so that a sufficient reinforcing effect is obtained. Cannot be obtained. Therefore, it is desirable to remove the converging agent which is incompatible with the resin or the unknown converging agent before the reinforcing fiber F is supplied to the reinforcing material supply hole 11b. The heat treatment apparatus 24 of this modification heats the reinforcing fiber F by energizing it to generate heat, thereby vaporizing and thermally decomposing the converging agent to remove it.

The heat treatment apparatus 24 is composed of metal grippers (clips) or the like arranged at predetermined intervals as electrodes 24a connected to the reinforcing fibers F, and is connected to a power supply apparatus 24b that supplies DC power or AC power to them. Since carbon fiber is a conductor, it generates heat by itself when an electric current is passed through it. The metal gripper may be opened and closed automatically. If the heat treatment apparatus 24 uses a metal gripper as the electrode 24a, the reinforcing fiber F is heat-treated by a certain length, but the electrical connection with the reinforcing fiber F is ensured, and abnormal heat is generated at the connecting portion. There is an advantage that such as is unlikely to occur.

The surface treatment device 25 performs a predetermined surface treatment on the reinforcing fiber F after being treated by the heat treatment device 24, for example, coating a specific converging agent or chemical having excellent adhesiveness to the resin. is there. There are no particular restrictions on the specific configuration of the surface treatment device 25. For example, a treatment tank (not shown) for storing such a converging agent or a chemical may be provided in the transport path of the reinforcing fiber F, and the reinforcing fiber F may be immersed in the converging agent or the like. A drug supply device 25a for supplying a converging agent or the like is connected to the surface treatment device 25. By recoding the reinforcing fiber F with a converging agent or the like that is compatible with the resin in this way, a sufficient reinforcing effect can be obtained by the reinforcing fiber F.

FIG. 3B is a modification in which the configuration of the heat treatment apparatus 24 is further changed in the modified example shown in FIG. 3A. In the modified example shown in FIG. 3B, the heat treatment apparatus 24 includes metal rollers arranged at predetermined intervals as electrodes 24a connected to the reinforcing fibers F, and the power supply apparatus 24b for supplying DC power or AC power to them. It is connected. The metal roller rotates according to the movement of the reinforcing fiber F to maintain an electrical connection to the moving reinforcing fiber F. In such a configuration, since the reinforcing fiber F can be continuously heat-treated at a desired feed rate including stopping, an effect that the operation of the injection device can be followed without any special control can be obtained.

FIG. 3C is a vertical cross-sectional view showing a schematic configuration of a further modification of the embodiment.
The major difference between this modification and the embodiment shown in FIG. 1 is the plasma processing apparatus 26 that applies atmospheric pressure plasma to the reinforcing fibers F before being supplied to the reinforcing material supply hole 11b to perform surface treatment. Be prepared.

Atmospheric pressure plasma is a technology that has received much attention in recent years. Briefly, plasma (ionized gas) is generated under atmospheric pressure by corona discharge, dielectric barrier discharge, RF discharge, or the like. Using the plasma, various surface treatments such as reduction of oxide film by hydrogen radicals, decomposition and removal of organic substances on the surface of substances, coating on the surface of substances by mixing various liquids and gases with plasma, and addition of functional groups are possible. Is. Processing with atmospheric pressure plasma has the advantage that it does not require a vacuum environment and can be continuously processed.

In this modification, the focusing agent coated on the reinforcing fibers F is removed by atmospheric pressure plasma. Further, at the same time, a specific converging agent may be coated or a specific functional group may be imparted. The surface treatment device 25 shown in FIG. 3A may be provided on the downstream side of the plasma treatment device 26 to recoat the reinforcing fibers F with a converging agent or the like having excellent adhesiveness to the resin.

The configuration of the plasma processing device 26 is not particularly limited. For example, plasma may be injected from an injection nozzle derived from a plasma generator (not shown), and the plasma may be directly blown onto the reinforcing fiber F during transportation. Alternatively, an electrode for plasma generation may be arranged in the transport path of the reinforcing fiber F to generate plasma in the vicinity of the reinforcing fiber F. The illustrated plasma processing device 26 includes a gas supply device 26a that supplies a gas to be plasma, and a power supply that supplies a power source for generating a corona discharge, a dielectric barrier discharge, an RF discharge, or the like in the plasma processing device 26. The device 26b is connected.

By the way, in the above-described embodiment and its modified example, the check valve is not provided at the tip of the screw, but if a tip device having a check valve function is attached to the tip of the screw, the injection pressure can be made highly accurate. You will be able to control it. However, it is necessary to devise a method for suppressing breakage of the reinforcing fiber F, which tends to occur at the check valve portion.

3D (a) to 3D (e) show a side view of a specific example of a tip device having a check valve function and suppressing breakage of the reinforcing fiber F, a vertical cross-sectional view along a central axis, and a tip side. It is a cross-sectional view when viewed, a cross-sectional view when viewed from the rear side, and a front view of a spherical valve body housed in a tip device. The vertical cross-sectional view of FIG. 3D (b) is obtained by cutting the tip device along a plane S including its center line, and the cross-sectional views of FIGS. 3D (c) and 3D (d) are all orthogonal to the center line of the tip device. It is cut along the plane T to be formed.

The tip device 27 is a rod-shaped body made of ordinary steel or various alloys and provided with a tapered portion 27a on the tip side, and a screw portion 27b is formed at the rear end portion for fixing to the screw 12. Further, the tip device 27 has a cylinder sliding contact portion 27c that is in sliding contact with the inner wall surface of the cylinder 11. The cylinder 11 is separated from the space V at the tip where the resin before injection is stored and the space W on the rear side where the resin is melted and kneaded by the cylinder sliding contact portion 27c. Inside the tip device 27, a valve body accommodating cavity 27d for accommodating the spherical valve body 28 so as to be movable back and forth is formed inside.

The spherical valve body 28 is a sphere made of ordinary steel or various alloys. The valve body accommodating cavity 27d has a cocoon shape in which a sphere having substantially the same size as the spherical valve body 28 is divided into two at the center and a cylinder is sandwiched between them. With such a shape, the spherical valve body 28 can smoothly move back and forth inside the valve body accommodating cavity 27d.

An opening 27e serving as a resin inlet is arranged on the outer wall surface behind the cylinder sliding contact portion 27c of the tip device 27, and an opening 27f serving as a resin outlet is arranged on the wall surface on the front side of the cylinder sliding contact portion 27c. A fluid passage 27g connecting these openings 27e and 27f is formed in combination with the valve body accommodating cavity 27d. The structure of the fluid passage 27g is as follows. The opening 27e, which is the inlet of the resin, communicates with the rear wall surface of the valve body accommodating cavity 27d, which comes into contact with the spherical valve body 28 when it moves to the rear side. The communication port 27h is opened when the spherical valve body 28 is on the front side, but when the spherical valve body 28 moves to the rear side, the communication port 27h is closed by the spherical valve body 28.

Then, a resin guide groove 27i is formed starting from the vicinity of the front side of the communication port 27h and ending at an appropriate position on the front wall surface of the valve body accommodating cavity 27d that comes into contact when the spherical valve body 28 moves to the front side. There is. The resin guide groove 27i serves as a path for the resin to move around the spherical valve body 28.
Further, an opening 27f serving as a resin outlet is arranged on the outer wall surface in front of the cylinder sliding contact portion 27c of the tip device 27, and the opening 27f is communicated with the bottom surface near the end point of the resin guide groove 27i. Since the communication port 27j is located on the bottom surface of the resin guide groove 27i, the spherical valve body 28 is always open regardless of the position on the front side or the rear side.

3E (a) and 3 (b) are side views of a specific example of a tip device for explaining a state when the spherical valve body moves back and forth. In these figures, the gray arrows indicate the movement of the resin P.
The spherical valve body 28 melts the resin and moves back and forth in the valve body accommodating cavity 27d due to the difference between the pressure of the resin in the space W on the rear side of the cylinder 11 and the pressure of the resin in the space V at the tip of the cylinder 11. That is, when the tip device 27 (screw 12) retracts, the pressure of the resin P in the space W on the rear side of the cylinder 11 increases, and the spherical valve body 28 receives a reaction force from the resin P and moves to the front side. As a result, the fluid passage 27g is opened. On the other hand, when the tip device 27 (screw 12) advances, the pressure of the resin P in the space V at the tip of the cylinder 11 increases, and the spherical valve body 28 receives a reaction force from the resin P in the opposite direction to the above. Move to the rear side. As a result, the fluid passage 27g is in a closed state.

In short, the spherical valve body 28 moves back and forth in response to the reaction force of the fluid P accompanying the backward or forward movement of the tip device 27 in the cylinder 11, and the fluid passage 27g opens and closes. As a result, the tip device 27 exerts a check valve function. At this time, the spherical valve body 28 moves back and forth in a state where only the outer peripheral line portion is in contact with the wall surface of the valve body accommodating cavity 27d, and the area where the spherical valve body 28 slides at that time is small. It is very unlikely that the sliding surface will break.

FIG. 3F (a) is a side view of another example of the advanced device, and FIGS. 3F (b) and 3 (c) are cross-sectional views illustrating the operation of the advanced device. In FIGS. 3F (b) and 3 (c), the movement of the resin P is indicated by gray arrows. The same reference numerals are given to the elements common to the above example, and the description thereof will be omitted.

In this advanced device 27, the shape of the valve body accommodating cavity 27d is different from the above example. That is, the valve body accommodating cavity 27d has a shape in which a cylindrical portion 27d1 having a diameter smaller than that of the spherical valve body 28 and a cylindrical portion 27d2 having a large diameter are coaxially connected, and the spherical valve 28 body is accommodated in the large diameter cylindrical portion 27d2. Has been done. A plurality of guide ridges 27d3 for preventing rattling of the spherical valve body 28 are formed on the inner peripheral surface of the large-diameter cylindrical portion 27d2 in the front-rear direction, and the spherical valve body 28 is guided by the guide ridges 27d3. It moves back and forth on the axis of the large-diameter cylinder 27d2.

The opening 27e provided behind the cylinder sliding contact portion 27c communicates with the end portion of the small-diameter cylindrical portion 27d1. On the other hand, the opening 27f provided in front of the cylinder sliding contact portion 27c communicates with the end portion of the large-diameter cylindrical portion 27d2. At this time, the fluid passage 27g connecting the openings 27e and 27f is composed of the small-diameter cylindrical portion 27d1 and the vicinity of the inner peripheral surface of the large-diameter cylindrical portion 27d2 (the gap between the spherical valve body and the inner peripheral surface). Become. Further, the edges of the small-diameter cylindrical portion 27d1 and the large-diameter cylindrical portion 27d2 and the connecting portion are chamfered so as to be in contact with the spherical valve body 28 without a gap. Therefore, when the spherical valve body 28 retracts, the connecting portion is closed by the spherical valve body 28.

The mechanism for moving the spherical valve body 28 back and forth is the same as described above, whereby the fluid passage 27g is opened and closed, so that the tip device 27 exerts a check valve function. Further, since the spherical valve body 28 moves back and forth in a state of being in contact with only the guide protrusion 27d3 and the area where the spherical valve body 28 slides with each other is small at that time, the reinforcing fiber F is broken at the sliding surface. Is also very small. Further, in this example, since a sufficient passage width of 27 g of the fluid passage can be secured, the fluid can be passed smoothly.

Next, an injection molding apparatus formed by combining the screw injection apparatus with a molding die will be described.
FIG. 4 is a vertical cross-sectional view showing a schematic configuration of the injection molding apparatus.

In the figure, a part of the cylinder 11 constituting the injection device 10 and the molding die 31 are shown as the main parts of the injection molding device 30, and the frame part and the like holding these are omitted from the drawing. Here, a 3-plate type mold is adopted, but the mold is not limited to the 3-plate type.

The molding die 31 is composed of the first to third dies 31a to 31c.
The first mold 31a is fixed to the movable side mounting plate 32. The second and third molds 31b and 31c are attached to the fixed side mounting plate 33 so as to be able to advance and retreat. A nozzle receiving portion 33a for receiving the injection nozzle 13 of the injection device 10 is formed on the fixed side mounting plate 33.
A cavity 31d is formed on the surface of the first mold 31a, and a core 31e housed in the cavity 31d is formed on the second mold 31b. The workpiece of the molded product is formed by the cavity 31d and the core 31e.
Further, the third mold 31c is provided with a runner cavity 31f. A runner is formed by the back surface of the second mold 31b and the runner cavity 31f of the third mold 31c. The runner cavity 31f is connected to the surface of the core 31e through a thin gate and is connected to the injection nozzle 13 of the resin injection cylinder 22 through the spool.
Further, the protruding pin 34 penetrates from the back surface of the third mold 31c to the front surface of the core 31e. The protruding pin 34 can be moved forward and backward with respect to the third mold 31c, and the formed work can be pushed out from the core 31e.
The resin P injected from the cylinder 11 generates minute bubbles of the foaming gas by depressurization, and the resin P spreads to the cavity 31d while growing the bubbles. Since the bulk of the resin P increases due to the growth of bubbles, a gate connecting the cavity 31d and the runner cavity 31f is provided in the thin part of the work, whereby the resin P is the thin part of the work. It is considered desirable to proceed from the to the thick part.

5 (a) to 5 (d) are a series of cross-sectional views for explaining the operation of the injection molding apparatus in chronological order.

In FIG. 5A, the mold 31 is closed and the protruding pin 34 is in the retracted position. Further, the injection nozzle 13 of the cylinder 11 is communicated with the runner cavity 31f of the third mold 31c via the fixed side mounting plate 33. In this state, the resin P melted from the cylinder 11 is injected into the mold 31 to form the work. The temperature of the mold 31 is appropriately controlled in each of the resin injection and curing steps. The injection device 10 holds the resin under pressure for a predetermined time after injection and injection of the resin.

In FIG. 5B, the molding of the work 2 is completed, and the first and second dies 31a and 31b are opened. At this time, the runner 2a is separated from the resin injection cylinder 22 by retracting the cylinder 11. At this time, the work 2 is in a state of being fitted in the core 31e.

In FIG. 5C, the protruding pin 34 is advanced. As a result, the work 2 is pulled out of the core 31e, and the work 2 and the runner 2a are automatically cut and separated at the gate portion. The work 2 separated from the runner 2a is taken out from the mold 31 by the work taking-out device 40.

In FIG. 5D, the second mold 31b is separated from the third mold 31c. This makes it possible to remove the runner 2a from the third mold 31c.

Finally, the structural features of the work manufactured by the injection molding apparatus will be described with reference to FIGS. 6 (a) and 6 (b).

FIG. 6A is a simple cross-sectional view illustrating the mode of progress of the resin P in the mold 31. In the figure, the white arrow indicates the traveling direction of the resin P. It is considered that the traveling speed of the resin P is faster in the central portion than in the interface portion with the mold 31, and therefore more bubbles B are generated in the central portion.
Further, the resin P advances while actively bursting and evaporating the foaming gas from the interface with the space at the tip in the traveling direction, so that the interface with the space where the number of bubbles B is reduced is formed by the resin P that comes later. It is considered that it is pushed in the boundary direction with 31 to form a new interface portion with the mold 31. As a result, the tree P fat is solidified in a state where a small amount of bubbles B is contained in the interface portion with the mold 31 and a large number of bubbles B are contained in the central portion. The foaming gas evaporated from the resin P into the space inside the mold 31 is discharged to the outside from a vent portion provided at an appropriate position in the mold 31.

FIG. 6B is a simple cross-sectional view of the solidified work. As shown in the figure, the work 2 has a multi-layer structure in which a skin layer SL containing almost no bubbles B is formed on the surface layer portion, and a core layer CL containing many bubbles B is formed on the central portion of the thickness. The reinforcing fibers F are uniformly dispersed in the resin P, but since the skin layer SL has fewer bubbles B and a higher density than the core layer CL, the skin layer SL has a higher density than the core layer CL. The reinforcing fibers F are mixed at a high density. Therefore, the skin layer SL is stronger than the core layer CL.
As described above, according to the present embodiment, the reinforcing fiber F is dispersed in the resin, and the molded product does not contain coarse bubbles (500 microns or more) and contains a large amount of fine bubbles B (5 to 50 microns). Is obtained.

10 Screw injection device 11 Plasticization cylinder 11a Vent hole 11b Reinforcing material supply hole 11c Supercritical fluid supply hole 12 Screw 15 Induction heating coil 20 Reinforcing material supply device 21 Supercritical fluid supply device 23 Reinforcing material supply amount adjusting device 24 Heat treatment device 25 Surface treatment device 26 Plasma treatment device 27 Tip device 27c Cylinder sliding contact part 27d Valve body accommodating cavity 27e, 27f Opening 27g Fluid passage

Claims (9)

In a screw injection device with a plasticized cylinder with a screw interpolated
In the plasticized cylinder, a vent hole for discharging steam from the inside of the cylinder and a reinforcing material supply hole for supplying a predetermined reinforcing material into the cylinder are formed in the middle portion thereof, and the tip side of the hole is closer to the tip side. A screw injection device characterized in that a supercritical fluid supply hole for supplying a predetermined supercritical fluid is formed in the cylinder. In the screw injection device according to claim 1,
The plasticized cylinder is a screw injection device characterized in that an induction heating coil is wound around the peripheral wall surface thereof. In the screw injection device according to claim 1 or 2.
A reinforcing material supply device that supplies carbon fibers to the reinforcing material supply hole, and
A screw ejection device including a supercritical fluid supply device that supplies a supercritical nitrogen fluid to the supercritical fluid supply hole. In the screw injection device according to claim 3,
A screw injection device further comprising a reinforcing material supply amount adjusting device for freely adjusting the supply amount of the carbon fiber. In the screw injection device according to claim 3,
A screw injection device further comprising a heat treatment device that energizes carbon fibers before being supplied to the reinforcing material supply hole to generate heat. In the screw injection device according to claim 5,
A screw injection device further comprising a surface treatment device for applying a predetermined surface treatment to carbon fibers after being treated by the heat treatment device. In the screw injection device according to claim 3,
A screw injection device, further comprising a plasma processing device that applies atmospheric pressure plasma to the carbon fibers before being supplied to the reinforcing material supply hole to perform surface treatment. In the screw injection device according to any one of claims 1 to 7.
The screw is equipped with a tip device having a check valve function.
The advanced device is
It has a cylinder sliding contact portion that slides into the inner wall surface of the plasticized cylinder.
A valve body accommodating cavity for accommodating the spherical valve body so as to be movable back and forth is formed inside, and an opening arranged on the outer wall surface behind the cylinder sliding contact portion and an opening arranged on the outer wall surface in front of the cylinder sliding contact portion. A fluid passage connecting to and is formed in combination with the valve body accommodating cavity.
The spherical valve body is a screw injection device characterized in that it moves back and forth in response to a reaction force from a fluid accompanying the movement of the screw in the cylinder to open and close the fluid passage. An injection molding apparatus comprising a molding die combined with the screw injection apparatus according to any one of claims 1 to 8.

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