JPH05305640A - Kneading and injection molding method of composite resin and device thereof - Google Patents

Abstract

PURPOSE:To make the uniform and efficient kneading of functional powder and synthetic resin possible. CONSTITUTION:In the kneading and injection molding method concerned, with which the predetermined shaped composite material is obtained by kneading functional powder and synthetic resin as binder added to it and, after that, injecting, the mixture of the powder and the synthetic resin is kneaded under heat with a screw cylinder type kneader 2 so as to feed the resultant thermally kneaded matter as it is thermally melted to a separately provided injection machine 3 in order to inject the kneaded matter under the state being deaerated and metered with the injection machine from a nozzle 35 in a mold.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a kneading injection molding method and a kneading injection molding apparatus for a composite resin containing a functional powder.

[0002]

2. Description of the Related Art In recent years, a functional powder and a synthetic resin are mixed, kneaded and granulated, and then injection-molded to produce a molded product, which is provided with the function of the above-mentioned functional powder. Various functional products (composite resins) that are made to do so are manufactured. As such functional products, for example, plastic magnets are popular. This plastic magnet mixes powdery magnetic material (magnetic powder) with powdered synthetic resin, then heats this mixture, kneading and kneading the synthetic resin while melting, and A resin is coated on each of them and uniformly dispersed, and this kneaded product is injected into a mold to obtain a molded product having a predetermined shape. Since the powder magnetic material is contained in this molded product, a magnet can be obtained by applying a magnetic force. If a kneaded product containing anisotropic magnetic powder is molded while a magnetic field is applied to the mold cavity during injection, a magnetic force is applied in the easy magnetization axis direction, and a strong plastic magnet is obtained. By devising the mold, magnets of various shapes can be obtained, which is extremely convenient.

Conventionally, as a method for producing such a composite resin, a method is used in which granules (pellets) in which powder and resin are kneaded are prepared by a kneader provided separately, and the granules are put into an injection machine and melt-injected. However, there is a problem in that the thermal efficiency is poor because heating and melting are required twice for pellet formation and injection. Therefore, as a solution to such a problem in injection molding of a composite resin, for example, Japanese Patent Publication No. 56-47847.
The one disclosed by the publication is known. This publication describes a kneading injection molding method and apparatus for a uniaxial inline screw type composite resin.

[0004]

By the way, in recent years, in order to more strongly bring out the function of the functional powder, the amount of the functional powder mixed in the synthetic resin tends to increase,
If this amount increases, the viscosity of the mixture of the resin and the powder increases, and it becomes difficult to uniformly disperse the powder in the resin. Therefore, sufficient kneading and kneading must be performed more than ever, but no suitable method and apparatus have been found.

The one disclosed in the above Japanese Patent Publication No. 56-47847 is also a uniaxial in-line screw system, and although it is said that the screw shape and other various measures have been taken, the kneading machine and the injection machine are different from each other. Since the same shaft is used in common, the kneading operation and the injection operation cannot be controlled separately, and the powder must be injected in a state where sufficient dispersion in the resin cannot be realized. As a result, there is a disadvantage that a good molded product cannot be obtained.

[0006] Conventionally, in order to improve this, it has been necessary to increase the axial length, and in order to knead the composite resin in which the powder is highly mixed, the rotation trouble of the screw increases and during kneading. There was a problem that the screw was frequently damaged.

The present invention has been made in order to solve the above problems, and is a kneading injection molding of a composite resin which is small in size and can knead functional powder and synthetic resin uniformly and efficiently. It is an object to provide a method and an apparatus thereof.

[0008]

According to a first aspect of the present invention, there is provided a kneading injection molding method for a composite resin, wherein a powder having functionality is mixed with a synthetic resin as a binder, kneaded, and then injection molded to obtain a predetermined shape. In a kneading injection molding method of a composite resin to obtain a composite material, a mixture of the powder and the synthetic resin is heated and kneaded by a kneader having a rotating disc and a fixed disc, and the kneaded product obtained by the heat kneading Is supplied to an injection machine provided separately from the kneading machine in a heated and molten state, and the kneaded product is injected from a nozzle into a mold while deaerating and measuring with this injection machine. is there.

According to a second aspect of the present invention, there is provided a kneading / injection molding device for a composite resin, wherein a kneading raw material in which a synthetic resin as a binder is added to a functional powder is kneaded into a kneaded product, and the kneaded product is injected. In a kneading injection molding device of a composite resin that is used for molding to obtain a composite material having a predetermined shape,
This kneading injection molding apparatus is composed of a kneading machine having a rotating disk and a fixed disk for kneading kneading raw materials, and an injection machine for guiding a kneaded product derived from this kneading machine to a mold, and the kneading machine is external. A cylinder having a raw material introduction part for forming a frame and for introducing a kneading raw material, and a kneaded material discharge hole for discharging a kneaded material; and a material to be kneaded in the cylinder and rotated in the cylinder in the axial direction thereof. It consists of a rotating shaft with a screw formed on the outer peripheral part for transporting, and a plurality of rotating discs are attached to this rotating shaft, and peaks and valleys are alternately arranged on both sides of these rotating discs in a radial pattern. On the inner peripheral surface of the cylinder, annular fixed discs coaxially opposed to both sides of the rotary disc are attached, and peaks and valleys are alternately formed on both sides of these fixed discs in a radial pattern. The above injection machine only forms the outer frame. A casing having a nozzle for injecting a kneaded material at its tip, and a rotating shaft provided in the casing and having a screw formed on an outer peripheral portion thereof so as to rotate in the casing and transfer the material to be kneaded in the axial direction thereof. The kneaded material discharge hole of the kneader is connected to the kneaded material input hole provided in the body of the injection machine.

[0010]

According to the method for kneading and injection-molding a composite resin according to claim 1, the kneaded material obtained by heating and kneading is supplied to an injection machine provided separately from the kneading machine in a heated and molten state, and the kneaded material is obtained. Since a so-called twin-screw in-line screw kneading method of injecting into the mold is used, by controlling the kneading operation and the injection operation independently of each other, the other operation can be performed without being strongly restricted to one operation. It can be carried out satisfactorily and as a result the functional powder can be more completely dispersed in the synthetic resin.

Further, since the kneaded material kneaded by the kneading machine is delivered to the injection machine in a heating and melting state, it is not necessary to reheat the kneaded material once cooled as in the conventional case, and energy and labor can be saved. Can contribute to reduction.

According to the composite resin kneading injection molding apparatus of the second aspect, first, the peaks and the valleys are alternately and radially formed on both side surfaces of the rotary disk provided on the rotary shaft of the kneader.
On the inner peripheral surface of the cylinder of the kneading machine, annular fixed disks that are coaxially opposed to each other on both sides of the rotary disk are attached, and peaks and valleys are alternately formed on both sides of these fixed disks in a radial pattern. Therefore, the kneading raw material is sufficiently kneaded by being sufficiently sheared and divided and distributed while passing through the gap between the rotating disk and the fixed disk.

Further, the injection machine has an outer frame and a casing having a nozzle for injecting a kneaded material at its tip, and a casing which is provided in the casing and rotates in the casing to transfer the material to be kneaded in the axial direction. So-called twin-screw in-line screw consisting of a rotary shaft having a screw formed on the outer peripheral portion, and the kneaded product discharge hole of the kneader is connected to the kneaded product input hole provided in the body of the injection machine. Since the kneading method is employed, by controlling the kneading operation and the injection operation independently of each other, the other operation can be sufficiently performed without being strongly limited to one operation.

[0014]

1 is a cross-sectional side view of a kneading injection molding apparatus for composite resin according to the present invention. As shown in this figure, a kneading injection molding apparatus 1 according to the present invention includes a kneading machine 2 for kneading and kneading a mixture of functional powder and synthetic resin, and this kneading machine 2.
It is basically composed of an injection machine 3 for injecting the kneaded product discharged from the rotary shaft part thereof.

The kneading machine 2 comprises a rotary shaft 2a having a screw 22 for transferring the kneaded material and a rotary disk 21 for kneading and kneading on the outer peripheral surface thereof, and a casing 2b covering the rotary shaft 2a. ing. Then, the rotating disk 21
Are provided in the axial center of the rotary shaft 2a, a feed screw 22a is formed upstream of the rotary disk 21, and an extrusion screw 22b is downstream of the rotary disk 21. Has been formed. Such a kneading machine 2 is obliquely arranged on the upper part of the injection machine 3, and its rotating shaft 2a is rotated by a drive motor 23 provided on the base end side thereof.

Above the rotary shaft 2a having the feed screw 22a, there is provided a raw material hopper 4 for loading a mixture of functional powder and powdered synthetic resin. In order to supply the above mixture in the raw material hopper 4 into the kneading machine 2, a raw material feeding means 41 including a drive motor and a screw conveyor is provided below the raw material hopper 4.
Further, a raw material chute 42 communicating with the feed screw 22a is provided. A raw material feed portion F is formed by the raw material hopper 4, the raw material feeding means 41, the raw material chute 42 and the rotary shaft 2a of the feed screw 22a.

The rotary shaft 2 following the feed screw 22a
An annular fixed disk 21a protruding from the inner peripheral surface of the casing 2b toward the outer peripheral surface of the rotating shaft 2a is provided between each of the plurality of rotating disks 21 provided on the outer peripheral surface of a. ..

FIG. 2 is a front view showing an example of the rotating disk 21, and FIG. 3 is a front view showing an example of the fixed disk 21a. First, as shown in FIG. 2, a plurality of recesses 25 are provided on the front and back of the rotary disk 21 in a radial pattern from the center to the circumference. 24 are formed.

Then, as shown in FIG.
On the front and back of a, the concave portion 25 and the convex portion 24 of the rotary disk 21 are provided.
The same number of peaks 25 'and valleys 2 so that they face each other.
4'is provided. Recesses 25 of these rotating disks 21
And the number of convex portions 24, and the mountain portion 2 of the fixed disk 21a.
The number of 5'and valleys 24 'is the same as that of the rotary disk 21 on the upstream side.
The fixed disk 21a is smaller, and the larger it is toward the downstream side. A kneading and kneading section K is formed on the rotating shaft 2a of the kneading machine 2 by the rotating disk 21 and the fixed disk 21a.

At the downstream side of the kneading and kneading section K, a kneading material discharge section H is provided with an extrusion screw 22b on a rotary shaft 2a.
Are formed. A kneading machine discharge hole 26 communicating with the inside of the injection machine 3 is provided at the lower end of the kneading and kneading section K.

The injection machine 3 has a rotary shaft 3a arranged so as to extend in the horizontal direction and a casing 3 covering the rotary shaft 3a.
and b. The base end side of the rotary shaft 3a is connected to the drive device 5, and the drive force of the drive device 5 is obtained to rotate the rotary shaft 3a. An injection screw 31 is provided on the outer peripheral surface of the free end side of the rotary shaft 3a, and the kneading machine discharge hole 26 of the kneading machine 2 is a surface provided with the injection screw 31 on the surface of the rotary shaft 3a of the injection machine 3. It is affixed to a kneading material charging hole 37 provided above the casing 3b.

A light weight portion X is formed by the space formed between the inner peripheral surface of the casing 3b and the outer peripheral surface of the rotary shaft 3a provided with the injection screw 31.
By this injection screw 31, the kneaded material moves in the light weight portion X toward the tip side and accumulates in the gap between the conical portion 33 at the tip of the rotating shaft 3a and the tip of the casing 3b. When the weight of the kneaded material in this gap becomes small, the rotary shaft 3a is ejected toward the right in FIG. 1 by a drive mechanism (not shown) in the drive device 5, and the kneaded material at the tip of the conical portion 33 is discharged from the nozzle 35. Discharged from.

The light weight of the kneaded product is the injection screw 31.
Is performed by retreating and the amount of retreat is measured.

FIG. 4 is a sectional view of the tip portion of the injection machine 3. As shown in this figure, a sharp conical portion 33 is formed at the tip of the rotary shaft 3a, and a nozzle 35 for injection is bored at the tip of the casing 3b that opposes the tip of the conical portion 33. .. A tick ring 32 is provided slightly upstream of the conical portion 33. The conical portion 33 and the rotating shaft 3a are connected by a neck portion 34 having a diameter smaller than those of the conical portion 33, and the kneaded material passes through the gap between the neck portion 34 and the neck portion 34 and is fed onto the outer peripheral surface of the conical portion, Ejected from 35. The rotating shaft 3a provided with such a screw 31, the casing 3b, the tick ring 32, the conical portion 33, and the nozzle 35 form a lightweight portion X.

A degassing port 3 opened upward on the base end side of the kneading machine discharge hole 26 of the casing 3b of the injection machine 3.
6 is provided. In the injection machine 3, this degassing port 3
A degassing section D of the injection machine 3 is formed in a portion where the 6 is provided. In the degassing section D, no screw is formed on the outer peripheral surface of the rotating shaft 3a.

An electric heater 6 is provided so as to surround the outer peripheral surfaces of the casing 2b of the kneader 2 and the casing 3b of the injector 3, and the mixture supplied to the kneader 2 and the injector 3 are supplied. The kneaded product thus prepared is used for heating.

Since the composite resin kneading injection molding apparatus of the present invention is constructed as described above, in injection molding the composite resin, first, the casings 2b and 3b of the kneading machine 2 and the injection machine 3 are provided. The electric heater 6 is energized to preheat to a predetermined temperature. In this case, the electric heater 6 can be controlled so that the raw material feed section F, the kneading and kneading section K, the kneaded material discharging section H, and the X lightweight section have different temperatures, and each section is optimal. It is set in advance so that it will reach a proper temperature.

Thereafter, the functional powder and the synthetic resin crushed to a predetermined particle size are mixed in a predetermined mixing ratio,
The raw material is loaded into the raw material hopper 4.

Then, with the drive motor 23 in a movable state, the raw material feeding means 41 is operated to feed the raw material in the raw material hopper 4 to the raw material feed section F of the kneading machine 2 via the raw material chute 42. Then, the mixed raw material supplied to the surface of the rotary shaft 2a of the raw material feed section F is sent to the downstream side by the feed screw 22a, and sequentially moves to the kneading and kneading section K.

The mixed raw material supplied to the kneading and kneading section K passes through the gap formed between the rotary disk 21 and the fixed disk 21a provided in this section, and is rotated as shown in FIGS. The recesses 25 and the protrusions 24 of the disk 21 and the peaks 25 'and the valleys 24' of the fixed disk 21a receive a compressive force and a shearing force due to relative movement, and are sufficiently kneaded and kneaded,
It becomes a kneaded material and is transferred to the kneaded material discharge part H on the downstream side.

Then, the casing 2b of the kneaded material discharge part H
It is supplied to the lightweight section X of the injection machine 3 from the kneading machine discharge hole 26 provided at the lower end of the injection machine 3. Since the rotary shaft 3a of the injection machine 3 is rotated in advance by the drive of the drive device 5, the final kneading is performed by the rotation of the injection screw 31 provided on the surface of the rotary shaft 3a of the light weight portion X. ,And,
Casing 3 while being measured by this screw 31
The inside of b is moved to the tip side. The gas generated in the kneading machine 2 and the injection machine 3 is led out of the system from a degassing port 36 provided in the upper part of the casing 3b in the degassing section D of the injection machine 3 and separately subjected to a detoxification treatment. To be done.

As shown in FIG. 4, the kneaded product which has moved toward the tip through the gap between the inner peripheral surface of the casing 3b and the outer peripheral surface of the rotating shaft 3a has the inner peripheral surface of the tick ring 32 and the rotating shaft 3 as shown in FIG.
a, it advances through a gap with the outer peripheral surface of the neck portion 34, further passes through the outer peripheral surface of the conical portion 33, and is ejected from a nozzle 35 bored at the tip of the casing 3b toward a mold (not shown). To be done.

As described in detail above, the kneading machine 2 of the composite resin kneading injection molding method and apparatus of the present invention.
Since the rotating shafts 2a and 3a are different from each other to be biaxial and the biaxial kneading machine 2 and the injector 3 are connected so as to have a Y shape in a side view, The kneading / injection molding apparatus 1 as a whole can be configured compactly, and the rotating shaft 2a of the kneading machine 2 and the rotating shaft 3a of the injection machine 3 can be operated separately, so that it can be used as a functional powder or a binder thereof. It is possible to operate at different rotation speeds according to the properties of the synthetic resin used and other operating conditions, and the degree of freedom that can be dealt with during operation is dramatically increased, and high-quality composite resin Can be manufactured.

In this example, as the functional powder, strontium ferrite for magnetic field anisotropy (SrO.6FeO ₃ , grade No. OP-, manufactured by Nippon Beni Kogyo Co., Ltd.) was used.
71, the closest packing ratio of 65% by volume, and the synthetic resin to be added and mixed as a binder thereto is a powdered material of 12 nylon (grade No. P3014U) manufactured by Ube Industries, Ltd. Used as a raw material for kneading.

Regarding the functional powder (strontium ferrite for magnetic field anisotropy), a silane coupling agent (grade No.
1160) whose surface was coated was used. The amount of the silane coupling agent used was 0.5% by weight with respect to the strontium ferrite, and the strontium ferrite was diluted with alcohol to be sprayed on the strontium ferrite for coating. Then, kneading and injection molding were carried out by the kneading injection molding apparatus 1 according to the present invention with the mixing ratios thereof being as follows.

▲ Functional powder Strontium ferrite for magnetic field anisotropy 89% by weight ▲ Synthetic resin 12 Nylon 11% by weight Incidentally, as a comparative example, Japanese Patent Publication No. 56-47.
Injection molding was performed using the same raw material as above using a single-axis in-line screw type device described in Japanese Patent No. 847.

Then, the melt flow of the kneaded products of the obtained Examples and Comparative Examples, the maximum energy product of the magnetic force of the molded product (plastic magnet) and the functional powder (strontium ferrite for magnetic field anisotropy) of the molded product. The anisotropic rate was measured. Table 1 shows each measurement result.
Shown in.

[0038]

[Table 1]

As can be seen from this table, the melt flow value of the example is about 1.5 times the melt flow value of the comparative example, and the composite resin kneading injection molding method and apparatus according to the present invention are applied. It is shown that when the above composite resin is kneaded, extremely good fluidity can be imparted even if a large amount of the functional powder is mixed in the synthetic resin.

As a result, the maximum energy product and the anisotropy rate of the obtained plastic magnet are better in the example than in the comparative example.

[0041]

As described above, in the kneading injection molding method of the composite resin of the present invention, the kneaded product obtained by the heat kneading is supplied to the injection machine provided separately from the kneading machine in a heating and melting state. Since a so-called twin-screw in-line screw kneading method of injecting the kneaded product into a mold is adopted, by controlling the kneading operation and the injection operation independently of each other, the other operation is not strongly limited to the other operation. The above operation can be sufficiently performed, and as a result, the functional powder can be more completely dispersed in the synthetic resin.

Further, since the kneaded material kneaded by the kneading machine is delivered to the injection machine in a heated and melted state, it is not necessary to reheat the kneaded material once cooled as in the conventional case, and energy and labor are saved. Can contribute to reduction.

The composite resin kneading injection molding apparatus of the present invention comprises:
Mountains and valleys are alternately formed radially on both sides of a rotary disc provided on the rotary shaft of the kneader, and the inner peripheral surface of the cylinder of the kneader is coaxially opposed to both sides of the rotary disc. An annular fixed disk is attached, and peaks and valleys are alternately formed on both side surfaces of these fixed disks in a radial pattern, so that the kneading raw material is sufficiently supplied while passing through the gap between the rotary disk and the fixed disk. Kneaded well due to shearing, splitting and distribution.

Further, the injection machine has an outer frame and a casing having a nozzle for injecting a kneaded material at the tip, and a casing which is provided in the casing and rotates in the casing to transfer the material to be kneaded in the axial direction. So-called twin-screw in-line screw consisting of a rotary shaft having a screw formed on the outer peripheral portion, and the kneaded product discharge hole of the kneader is connected to the kneaded product input hole provided in the body of the injection machine. Since the kneading method is employed, by controlling the kneading operation and the injection operation independently of each other, the other operation can be sufficiently performed without being strongly limited to one operation.

Therefore, by adopting such a method and apparatus of the present invention, it is possible to simultaneously perform sufficient kneading and injection of different functional powders and synthetic resins, which are effective. This is advantageous because it is possible to obtain a composite resin that is physically mixed.

[Brief description of drawings]

FIG. 1 is a side sectional view of a kneading injection molding apparatus according to the present invention.

FIG. 2 is a front view of a rotating disk.

FIG. 3 is a front view of a fixed disk.

FIG. 4 is a sectional view of a tip portion of the injection machine.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Kneading injection molding apparatus 2 Kneading machine 2a Rotating shaft 2b Casing 21 Rotating disk 21a Fixed disk 22 Screw 22a Feed screw 22b Extruding screw 23 Drive motor 24 Convex portion 25 Recessed portion 24 'Valley portion 25' Mountain portion 3 Injector 3a Rotating shaft 3b Casing 31 Screw 32 Tick ring 33 Conical part 34 Neck part 35 Nozzle 36 Degassing port 4 Raw material hopper 41 Raw material feeding means 42 Raw material chute 5 Driving device 6 Electric heater F Raw material feeding part K Kneading and kneading part H Kneaded material discharging part X Light weight part D degassing unit

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Claims (2)

[Claims] 1. A kneading injection molding method of a composite resin, wherein a synthetic resin as a binder is added to a powder having functionality and kneaded and then injection-molded to obtain a composite material having a predetermined shape. The mixture is heated and kneaded by a kneader having a rotating disc and a fixed disc, and the kneaded product obtained by this heating and kneading is supplied to an injection machine provided separately from the kneading machine in a heating and melting state, A kneading injection molding method for a composite resin, characterized in that the kneaded product is injected from a nozzle into a mold while degassing and measuring with this injection machine. 2. A kneading material in which a synthetic resin as a binder is added to a powder having functionality is kneaded to obtain a kneaded product, and the kneaded product is injection-molded to obtain a composite material having a predetermined shape. In a kneading injection molding machine for composite resin,
This kneading injection molding apparatus is composed of a kneading machine having a rotating disk and a fixed disk for kneading kneading raw materials, and an injection machine for guiding a kneaded product derived from this kneading machine to a mold, and the kneading machine is external. A cylinder having a raw material introduction part for forming a frame and for introducing a kneading raw material, and a kneaded material discharge hole for discharging a kneaded material; and a material to be kneaded in the cylinder and rotated in the cylinder in the axial direction thereof. It consists of a rotating shaft with a screw formed on the outer peripheral part for transporting, and a plurality of rotating discs are attached to this rotating shaft, and peaks and valleys are alternately arranged on both sides of these rotating discs in a radial pattern. On the inner peripheral surface of the cylinder, annular fixed discs coaxially opposed to both sides of the rotary disc are attached, and peaks and valleys are alternately formed on both sides of these fixed discs in a radial pattern. The above injection machine only forms the outer frame. A casing having a nozzle for injecting a kneaded material at its tip, and a rotating shaft provided in the casing and having a screw formed on an outer peripheral portion thereof so as to rotate in the casing and transfer the material to be kneaded in the axial direction thereof. And a kneading material discharge hole of the kneading machine, which is connected to a kneading material charging hole provided in a body portion of the injection machine.