JP2001277296A - Method and apparatus for directly supplying additive - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method and apparatus for directly supplying an additive, capable of certainly preventing addition irregularity without generating surplus cost. SOLUTION: In a method for directly supplying the additive M to the base resin material N supplied to the screw part C4 of a plastic injection molding machine C, the additive M is directly supplied to the screw part C4 in a predetermined ratio at the same time when the base resin material N is supplied to the screw part C4.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a method and an apparatus for directly supplying an additive to a base resin material supplied to a screw portion (material supply port) of a plastic injection molding machine.

[0002]

2. Description of the Related Art A base resin material supplied to a plastic injection molding machine is a natural material or a natural material containing a crushed material or a recycled material, which can be a main material of a resin molding material, and an additive material. In contrast, additives are those that can be secondary materials to the base resin, such as colorants (masterbatch materials, pigments, dyes), stabilizers, antistatic agents, and flame retardants. Say.

The base resin material and the additive are mixed and supplied to a plastic injection molding machine. In the plastic injection molding machine, the mixed resin molding material is kneaded and plasticized, and at the same time, the coloring in the additive is performed. An agent or the like is dispersed throughout and injected to form a resin molded product.

FIGS. 6, 7 and 8 are schematic views showing the steps of injection, holding pressure and metering in a conventional plastic injection molding machine equipped with a device for directly supplying an additive.

As shown in these drawings, the plastic injection molding machine C includes a hopper C1 for storing a base resin material N, and the base resin material N stored in the hopper C1 is provided at a lower end of the hopper C1. Material input port C2
From its own weight, and is supplied to the screw portion C4 in the cylinder C3.

A hopper C1 of a plastic injection molding machine C
Is provided with a device 150 for directly supplying the additive material. The device 150 includes an additive hopper 101 for storing the additive material M, and a metering rotor 121 for measuring a predetermined ratio of the additive material M to the base resin material N. Weighing machine 102 that weighs by controlling the rotation of, and conveying means 1 that guides weighed additive material M to material inlet C2 of plastic injection molding machine C
03 is provided.

In the plastic injection molding machine C, the additive material M is measured at a predetermined ratio with respect to the supplied base resin material N by the measuring machine 102, and guided to the material input port C2 via the conveying means 103. The additive material M is supplied to the screw portion C4 together with the base resin material N. Such a method of supplying the additive material M is referred to as a method of directly supplying the additive material.

[0008] The base resin material N and the additive material M (hereinafter, also referred to as "mixture material NM") thus supplied are transferred forward by the rotational transfer action of the screw portion C4. It is pushed back by the mixed material NM transferred and accumulated at the tip, and retreats. A heater C6 is provided around the cylinder C3, and the mixed material NM is provided.
Is heated and kneaded while being transferred to the tip of the screw portion C4, and is plasticized.

The retracted position of the screw portion C4 being pushed back is electrically detected by a detector (not shown), and the rotation of the screw portion C4 is stopped. This step is called “weighing” (see FIG. 8).

[0010] By this measurement, one shot of the mixture NM is accumulated in the tip of the cylinder C3 in front of the screw portion C4. When the measurement is completed, the weighing machine 102 of the apparatus 100 for directly supplying the additive is , Measuring rotor 1
The rotation of 21 is stopped, and the supply of the additive material M is stopped.

Then, the screw portion C4 is pushed forward by a hydraulic cylinder (not shown) provided at the base end of the screw portion C4, and the heat-plasticized mixed material NM is discharged from the nozzle C5 at the tip of the cylinder C3 into the mold K. Injected into. This step is called “injection” (see FIG. 6).

In order to prevent the mixture NM finally injected into the mold K from returning to the inside of the cylinder C3, the screw portion C4 is held for a certain period of time without any change. This step is referred to as “holding pressure” (see FIG. 7). The holding time is not uniform depending on the type of the mixed material NM, the mixing ratio, and the like.
In some cases, little pressure is needed.

Thus, the plastic injection molding machine C is
The process of weighing (FIG. 8) → injection (FIG. 6) → holding pressure (FIG. 7) is sequentially repeated to produce a resin molded product with the mold K, and the apparatus 150 for directly supplying the additive material, Screw part C
4 is supplied directly to the vicinity of the material input port C2 to the hopper C1 of the base resin material N, a predetermined amount of the additive material M is added in advance, mixed well, and then supplied to the screw portion C4. As compared with the mixing type, the mixing unevenness of the additive material M was further reduced, and the color change and the like could be shortened.

Here, FIGS. 6, 7, and 8 are arranged in the order of injection, holding pressure, and measurement instead of the order of measurement, injection, and holding pressure. This is because the feature that the material M is directly supplied is taken into consideration, and this is compared with a conventional example.

[0015]

However, in the apparatus 150 for directly supplying the additive, as shown in FIGS. 6, 7, and 8, the weighing machine 102 weighs only the weighing signal of the screw section C4. When the rotor 121 is rotated, the additive material M is supplied only at the time of metering, and is not supplied at the time of injection and holding pressure.

On the other hand, the material inlet C2 is not provided with a means for opening and closing the supply of the base resin material N to the screw portion C4, and if there is a space below the material inlet C2, The material N has a structure that falls naturally.

However, when measuring, the screw portion C
4 retreats, a portion behind the material input port C2 is formed. This portion becomes a blank portion C4a to which neither the base resin material N nor the additive material M is supplied, and the screw portion C4 is pushed forward during injection. In the meantime, this blank portion C4a is positioned below the material input port C2,
At this time, only the base resin material N was supplied to the blank portion C4a of the screw portion C4 without supplying the additive material M from the device 150 for directly supplying the additive material.

FIG. 9 is a conceptual diagram showing a kneading state when this apparatus 150 is used. As described above, since only the base resin material N is supplied at the time of injection, the screw portion in the cylinder C3 is provided. C4 is a state in which a layer mixed with the mixture NM of the base resin material N and the additive material M shown by hatching in FIG. 9 and a layer filled only with the base resin material N shown by a space alternately appear (see “Flow”). Mark ").

Such a flow mark is generated because the screw portion C4 of the plastic injection molding machine C has a structure in which the material is transferred forward by the rotary transfer operation, so that the kneading in the radial and circumferential directions is sufficiently performed. However, since kneading in the axial direction is difficult, kneading to eliminate the supply unevenness by the device 150 cannot be performed. When the resin is injected into the mold K in this state, it is easy to cause addition unevenness in the resin molded product. There was a problem.

It has also been proposed to provide a mixing nozzle (not shown) at the tip end of the cylinder C3 in order to make this uniform, but it is not possible to knead the plasticized resin material without unevenness, and the cost is also reduced. It was to increase by that much. In addition, in a translucent resin molded product that has been increasing in recent years, the addition unevenness such as the color unevenness is more conspicuous, and a method and apparatus for more reliably preventing the addition unevenness have been demanded.

An object of the present invention is to provide a method and apparatus for directly supplying an additive capable of reliably preventing unevenness in addition without generating extra cost.

[0022]

According to the first aspect of the present invention, there is provided a method of directly supplying an additive to a base resin material supplied to a screw portion of a plastic injection molding machine. When the base resin material is supplied to the screw portion, the additive material is simultaneously supplied directly to the screw portion at a predetermined ratio.

Here, the direct supply is not a batch type or a mixed type, as described above, and the additive material is continuously supplied to the screw portion as the base resin material is supplied to the screw portion. The supply port for supplying the additive material to the base resin material is located near the material input port to the screw part of the plastic injection molding machine, or an appropriate supply port for the base resin material hopper. Position.

The predetermined ratio refers to a ratio of an additive to a base resin material which is a target for manufacturing a resin molded product. In order to achieve the predetermined ratio, a screw portion is used during measurement or injection. The amount of the additive is adjusted such that the ratio of the additive to the amount of the base resin material supplied to the substrate becomes the predetermined ratio.

Simultaneously, regardless of the steps on the screw side of the plastic injection molding machine, such as metering, injection, and holding pressure, when the base resin material is actually supplied, the additive material is supplied at the same time. It is.

Conventionally, the method of directly supplying the additive is as follows.
Focusing on the fact that the base resin material is supplied even at the time of injection, which has been overlooked, from this fact, anyway, when the base resin material is supplied, the additive material is also supplied. A simple and obvious solution.

In this way, when the base resin material is supplied to the screw portion, the additive material is always supplied at a predetermined ratio, so that the addition of the additive material does not occur, and the uniformly kneaded mixture is added to the mold. Only materials can be supplied. Further, since only the supply timing of the additive is changed, the conventional apparatus can be used as it is, and no extra cost such as a mixing nozzle is generated.

The method for directly supplying an additive according to a second aspect is characterized in that, in the first aspect, the additive is directly supplied at a predetermined ratio not only at the time of measurement but also at the time of injection.

This method of directly supplying the additive material embodies the features of the present method in accordance with the actual process on the screw side of the plastic injection molding machine. In the case of the injection which has not been performed, the additive material is supplied, and the same effect as that of the first aspect is exhibited.

The apparatus for directly supplying an additive according to claim 3 is an apparatus for directly supplying an additive to a base resin material supplied to a screw portion of a plastic injection molding machine, wherein the base resin material is When being supplied to the screw section, the additive is simultaneously supplied directly to the screw section at a predetermined ratio.

This apparatus embodies the method of directly supplying the additive according to the first aspect, and has the same effect as the first aspect.

A device for directly supplying an additive according to a fourth aspect is characterized in that, in the third aspect, the additive is directly supplied at a predetermined ratio not only at the time of measurement but also at the time of injection.

This apparatus embodies the method of directly supplying the additive according to the second aspect, and has the same effect as the second aspect.

[0034]

Embodiments of the present invention will be described with reference to the drawings.

FIG. 1 is a schematic view showing a state of an injection step in a plastic injection molding machine provided with an example of an apparatus for directly supplying an additive according to the present invention. Hereinafter, the plastic injection molding machine is the same as the conventional example described with reference to FIG. 6, and therefore, the same portions are denoted by the same reference numerals and overlapping description will be omitted.

The hopper C1 of the plastic injection molding machine C
The device 5 for directly supplying the additive material attached to the
Hopper 1 for storing the additive material M, a weighing machine 2 for metering the additive material M at a predetermined ratio according to the supply amount of the base resin material N, and feeding the additive material M measured by the weighing machine 2 to a plastic injection molding machine C A supply port 3 leading to the port C2 is provided.

The weighing machine 2 includes a weighing rotor 21 and a rotor case 22 having a control unit (not shown) for controlling the rotation of the weighing rotor 21. The rotation and stop of the weighing rotor 21 are transmitted to the screw unit C4. By controlling the additive material M at a predetermined ratio with respect to the supplied base resin material N, the supply amount of the additive material M can be adjusted or the supply can be stopped.

The device 5 for directly supplying the additive is different from the conventional one, and as shown in the figure, also at the time of injection, the additive 2 is measured at a predetermined ratio by the meter 2 and supplied to the material inlet C2. . Therefore, at the time of injection, the additive material M is also supplied when the blank portion C4a of the screw portion C4 is located below the material input port C2 and the base resin material N is supplied to the blank portion C4a of the screw portion C4. The addition unevenness of the additive material M can be prevented.

If a measuring instrument (not shown) capable of measuring the amount of the base resin material N supplied to the screw portion C4 is provided, and this measuring instrument (not shown) and the control section are linked, The control unit may calculate a predetermined ratio with respect to a numerical value of a measuring device (not shown), and automatically adjust the supply amount of the additive material M.

FIGS. 2, 3 (a) and 3 (b) respectively show
FIG. 2 is a schematic diagram showing a state of a pressure holding and measuring process of the plastic injection molding machine of FIG. 1.

The operation of the screw portion in each of the steps shown in FIGS. 1, 2, and 3 is the same as that of the conventional example shown in FIGS. The difference is that here the device 5 for directly supplying the additive is
As clearly shown in FIG. 1, the additive material M is supplied also at the time of injection. Therefore, as can be seen from the drawing, the length of the cylinder C3 of the plastic injection molding machine C is increased in any of the steps. The mixture NM uniformly over the
Since the base resin material N and the additive material M are distributed, unevenness in the addition of the additive material M can be prevented.

FIG. 3B shows a state in which the measuring step has been completed. As can be seen from FIG. 3B, at the time of the completion of the measuring, the screw portion C4 is located at a portion after the material inlet C2. The blank portion C4a is formed. When the process proceeds to the injection step in FIG. 1 from this state, the base resin material N is inserted into the blank portion C4a through the material inlet C2.
It can be understood that the additive material M is supplied by natural fall.

FIGS. 4A and 4B are time charts showing the supply timing of the additive in the apparatus for directly supplying the additive according to the present invention.

In this time chart, the horizontal axis is a time axis, and the vertical axis is a binary value of signal on / off (1, 0).
It shows the timing of the weighing operation of the present apparatus, that is, the apparatus for directly supplying the additive of the present invention, with respect to the injection signal, the dwelling signal, and the weighing signal of the molding machine.

FIG. 4A shows an example in which the metering operation of the apparatus for directly supplying an additive according to the present invention is synchronized with the injection signal and the metering signal of the molding machine, and FIG. An example of synchronization with a pressure signal is shown.

As described above, by synchronizing the metering operation of the device for directly supplying the additive material to the injection signal of the molding machine or the like, the additive material corresponding to the supply of the base resin material can be supplied. Further, in this case, if the measurement counter of the device for directly supplying the additive is synchronized with the counter signal of the injection or the measurement of the molding machine, the two can be accurately associated with each other.

Further, as shown in FIG. 4B, the additive material is directly supplied not only at the time of injection but also at the time of holding pressure. If the dwell time is short, even if the additive is supplied during this time, the effect may be small.Thus, the number of times the additive signal is turned on and off can be reduced, and control can be performed. This is because some aspects become easier.

Further, the case where the base resin material flows into the screw portion not only during the injection but also during the dwelling time can be considered from the relationship between the injection time and the fluidity of the base resin material. Since the base resin material is also supplied during the pressure holding, the additive material is supplied in consideration of this.

FIG. 5 is a conceptual diagram showing a kneading state in the case of using the direct supply apparatus of the present invention.

As shown in FIG. 1, when the device 5 for directly supplying the additive is used, the additive M is supplied to the screw portion C4 at the same time as the base resin N at the time of injection.

Accordingly, the mixed material NM indicated by oblique lines is distributed all over the screw portion C4. If the mixed material NM is injected into the mold K in this state, the additive material M with respect to the base resin material N can be obtained. Can be made uniform, the addition unevenness of the resin molded article can be reliably prevented, and no flow mark is generated.

Further, since only the supply timing of the additive material M is changed, it is not necessary to provide an additional hardware device such as a mixing nozzle (not shown), and the cost is not increased.

In this way, the apparatus for directly supplying the additive can surely prevent the non-uniformity of the additive, so that the color due to the non-uniformity of the additive M, such as a translucent resin molded article, which has been increasing in recent years, is increased. The present invention can also be suitably used for a plastic injection molding machine for molding a product in which unevenness is conspicuous.

Here, an example has been described in which the direct supply device 5 is attached to the existing hopper C1 for the base resin material N of the plastic injection molding machine C, but the plastic injection molding machine C is newly provided with a base resin material. When the hopper for N is installed, a device for directly supplying the additive can be provided integrally, in which case the cost can be reduced as compared with a case where the device for directly supplying the additive is added later. I can plan.

[0055]

According to the method for directly supplying an additive according to the first aspect, the additive is always supplied at a predetermined ratio when the base resin material is supplied to the screw portion. Does not occur, and the mixed material uniformly kneaded can be supplied to the mold. Further, since only the supply timing of the additive is changed, the conventional apparatus can be used as it is, and no extra cost such as a mixing nozzle is generated.

According to the method for directly supplying the additive according to the second aspect, in addition to the effect of the first aspect, the feature of the present method is made corresponding to the actual process on the screw portion side of the plastic injection molding machine. Specifically, the additive material is supplied also at the time of injection, which has not been noticed as the supply timing of the additive material, so that the same effect as that of claim 1 is exerted.

According to the apparatus for directly supplying an additive according to the third aspect, since the method for directly supplying the additive according to the first aspect is embodied, the same effect as that of the first aspect is exhibited.

According to the apparatus for directly supplying an additive according to the fourth aspect, in addition to the effect of the third aspect, the method for directly supplying the additive of the second aspect is embodied, so that the same as the second aspect is achieved. Demonstrate the effect of.

[Brief description of the drawings]

FIG. 1 is a schematic diagram showing a state in an injection process in a plastic injection molding machine provided with an example of an apparatus for directly supplying an additive according to the present invention.

FIG. 2 is a schematic view showing a state in a pressure holding step of the plastic injection molding machine of FIG. 1;

3 (a) and 3 (b) are schematic views showing a state in a measuring step of the plastic injection molding machine of FIG. 1;

FIGS. 4A and 4B are time charts showing the supply timing of the additive in the apparatus for directly supplying the additive according to the present invention.

FIG. 5 is a conceptual diagram showing a kneading state when an apparatus for directly supplying an additive according to the present invention is used.

FIG. 6 is a schematic view showing a state of an injection process in a conventional plastic injection molding machine equipped with a device for directly supplying an additive.

FIG. 7 is a schematic view showing a state of a holding pressure process in a conventional plastic injection molding machine equipped with a device for directly supplying an additive.

FIG. 8 is a schematic view showing a state of a measuring step in a conventional plastic injection molding machine equipped with a device for directly supplying an additive.

FIG. 9 is a conceptual diagram showing a kneading state when a conventional direct supply device is used.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Hopper 2 Measuring machine 3 Supply port 5 Device for directly supplying additive material C Plastic injection molding machine C4 Screw part N Base resin material M Additive material

 ────────────────────────────────────────────────── ─── Continuing from the front page (72) Inventor Kensuke Yamashita 2-19, Shojitsuda, Hirakata-shi, Osaka F-term in Matsui Manufacturing Co., Ltd. (reference) 4F206 AB12 JA07 JD03 JF02 JF13 JM01 JN03 JT02

Claims (4)

[Claims] 1. A method of directly supplying an additive material to a base resin material supplied to a screw portion of a plastic injection molding machine, wherein when the base resin material is supplied to the screw portion, the additive material is simultaneously added at a predetermined ratio. A method for directly supplying an additive material, wherein the material is directly supplied to the screw portion. 2. The method for directly supplying an additive according to claim 1, wherein the additive is directly supplied at a predetermined ratio not only at the time of measurement but also at the time of injection. 3. An apparatus for directly supplying an additive material to a base resin material supplied to a screw portion of a plastic injection molding machine, wherein when the base resin material is supplied to the screw portion, the additive material is simultaneously added at a predetermined ratio. An apparatus for directly supplying an additive, wherein the additive is directly supplied to the screw section. 4. An apparatus for directly supplying an additive according to claim 3, wherein the additive is directly supplied at a predetermined ratio not only at the time of measurement but also at the time of injection.