JPH0553618B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to an apparatus for feeding colored extrudate material to a plastic extruder, such as a wire coating extruder.

[Prior Art] Conventionally, in order to supply colored plastics using an extruder for coating colored plastics on electric wires, etc., in order to make the color uniform, color masterbatch and base pellets were accurately mixed at a certain ratio and then extruded. For example, as shown in Figure 3, an extrusion head B is placed at the tip of the extrusion screw part A
A hopper port D for supplying extruded plastic is provided to an extruder C having a hopper port D, and a mixing tank E is attached to this.
Color master batch weighing machine F is placed on top of this mixing tank E.
and base pellet weighing machine G are installed, and a stirring motor J having a stirring blade H is installed, and both weighing machines F and G measure the color masterbatch and base pellets at a constant ratio and discharge them into the mixing tank E. , which were mixed by a stirring blade H and supplied to the extrusion screw section A from the hopper port D of the extruder C.

In addition, as for extruding a mixture of pellets and flakes, as shown in Japanese Patent Application Laid-Open No. 57-93118, flakes obtained by cutting the collected resin film into thin pieces are stored in a flakes storage container.
The resin pellets are stored in a pellet storage container, the flakes in the flakes storage container are weighed using a gravimetric scale, and the flakes are supplied to a hopper equipped with stirring blades.
The pellets in the pellet storage container are weighed with a gravimetric scale and fed to a hopper equipped with stirring blades.In this hopper, the flakes and pellets are uniformly mixed with the stirring blade, and the mixture is transferred to a screw feeder. There is a known method in which the extruder is fed to an extruder.

In addition, as a hopper equipped with a level meter, as shown in Japanese Utility Model Application Publication No. 50-96666, a hopper having one raw material inlet at the upper end and multiple raw material outlet ports at the lower end is used. In addition to providing a level meter to detect the upper limit level of the raw material in the hopper, a timer is also installed. When the raw material in the hopper falls below the level of the level meter, the timer starts and after a predetermined period of time, the raw material is not fed. There is a known device in which the solenoid valve at the mouth opens to start feeding the raw material into the hopper, and when the raw material in the hopper reaches the level of the level meter, the solenoid valve closes and stops the feeding of the raw material and the timer. .

[Problems to be Solved by the Invention] In the conventional device as shown in FIG. Therefore, if you change the coloring of the extruded plastic, the color of the previous material will mix, resulting in a defective product.
To prevent this, the operation of the extruder must be stopped for a long period of time to thoroughly clean the inside of the mixed layer E. In particular, in order to increase the operating rate of the wire extrusion coating line and improve productivity, it is necessary to realize continuous color changes in which the coloring of the extrusion coating can be changed without stopping the line operation. Stopping line operation for long periods of time is a major problem.

Furthermore, the method shown in the above-mentioned patent application publication also has the same problem as the above-mentioned one shown in the third figure because a stirring blade is provided in the hopper. Since the flakes and pellets must be weighed in a container and then fed to a hopper having stirring blades, there is a problem that the weighing and feeding operations of flakes and pellets do not proceed quickly.

Furthermore, the device disclosed in the above-mentioned utility model application publication is configured so that the raw material is fed into the hopper by opening the electric shaft valve of the raw material feed port provided at the upper end of the hopper without measuring the raw material. Due to this, it is not possible to measure the predetermined amounts of each of the two types of raw materials such as color master batch and base pellets, feed them to the hopper, and then push out the mixture. Since the time is set, there are problems in that it is not possible to accurately measure the raw materials, and it is not possible to precisely change the color of extruded plastic.

The present invention solves the above-mentioned problems, and makes it possible to continuously change the color of extrusion coating without stopping the operation of the wire extrusion coating line, thereby increasing the operating rate of the line and improving productivity. The purpose is to provide a supply device.

[Means for Solving the Problems] In order to achieve the above object, the material supply device for a plastic extruder of the present invention includes a color master button above a cylindrical chute 1 whose lower end communicates with the extrusion screw part A. A measuring device 5 for measuring and feeding the base pellet material and a measuring device 6 for measuring and feeding the base pellet material are installed, and an upper limit level detection device 3 for detecting the upper limit level of the material in the cylindrical chute 1. A lower limit level detection device 4 is installed to detect the lower limit level, the detection output of the lower limit level detection device 4 starts the measuring instruments 5, 6, and the detection output of the upper limit level detection device 3 starts the measuring instruments 5, 6.
6 is stopped.

[Function] The cylindrical chute 1 does not have stirring blades like the conventional one inside and does not stir inside the cylindrical chute 1, so unlike the conventional one, a large amount of powder accumulates inside the cylindrical chute 1 and static electricity is generated. There is no need to stop the extruder operation for a long time to clean the inside of the cylindrical chute.

The color master batch measuring device 5 receives a color master batch 11 of a desired color, measures a predetermined amount of it, and feeds it into the cylindrical chute 1, and the base pellet measuring device 6 receives a base pellet 12 and feeds the predetermined amount of the same into the cylindrical chute 1. is weighed and fed into the cylindrical chute 1.

The color masterbatch 11 and base pellets 12 fed into the cylindrical chute 1 are alternately layered and overlapped inside the cylindrical chute 1, and then fed into the extrusion screw section A where they are kneaded uniformly and without color unevenness. A colored plastic of the desired density is extruded from extrusion head B.

When the amount of color masterbatch 11 and base pellet 12 in the cylindrical chute 1 decreases due to this extrusion and the residual level of material in the cylindrical chute 1 falls to the permissible lower limit, the lower limit level detection device 4 detects this. , The color masterbatch measuring device 5 and the base pellet measuring device 6 are started by the detection output, and the color masterbatch 11 and the base pellet 12 are measured and fed into the cylindrical chute 1.

When the amount of color master batch 11 and base pellet 12 fed into the cylindrical chute 1 increases and their level rises to the allowable upper limit amount, the upper limit level detection device 3 detects this, and the detection output is used to detect the above-mentioned. Each meter 5, 6 stops feeding the color masterbatch 11 and base pellets 12 into the cylindrical chute 1.

To change the coloring of the extruded plastic, the coloring can be changed by simply operating the scale 5 of the color masterbatch of the desired color while the extruder continues to operate without stopping.

As mentioned above, by starting the measuring instruments 5 and 6 by the detection output of the lower limit level detection device 4 and stopping the measurement instruments 5 and 6 by the detection output of the upper limit level detection device 3, the line operation can be started without stopping. By making it continuous, the coloring of the extrusion coating can be changed, improving the operating rate of the wire extrusion coating line and improving productivity.

[Embodiment] Fig. 1 shows an embodiment of the present invention, in which A is an extrusion screw section, B is an extrusion head, and a transparent cylindrical chute 1 for feeding extrusion material to the extrusion screw section A is shown. , the lower end is pushed out from the screw part A
Install it in communication with the Reference numeral 2 denotes a conical chute portion at the upper end of the cylindrical chute 1. An upper limit level detection device 3 made of a photo switch or the like is provided on the outside of the upper part of this cylindrical chute 1, and a lower limit level detection device 4 made of a photo switch or the like is provided on the outside of the lower part. The upper limit level of the allowable amount of the extruded material is detected by the upper limit level detection device 3 by transmitting light through the transparent cylindrical wall, and the lower limit level of the allowable amount is detected by the lower limit level detecting device 4 by transmitting light through the transparent cylindrical wall. Detect.

A color masterbatch scale 5 and a base pellet scale 6 are installed above the conical chute 2. Each of these measuring instruments is, for example, a volume measuring type as shown in the second diagram, and one or several measuring holes 9 of a predetermined volume are provided in a rotating disk 8 installed in a tank 7. Make sure that only a predetermined amount of material enters the tank 7, and fill the measuring hole 9 by rotating the disk 8.
When the material reaches the top of the tube 10, a predetermined amount of the material contained in the measuring hole 9 falls into the tube 10 and is discharged, thereby measuring and supplying a predetermined amount.

The operation of each measuring device 5, 6 is controlled by the detection output of the above-mentioned upper limit and lower limit level detection devices 3, 4, and the level of the allowable lower limit amount of extruded material in the transparent cylindrical chute 1 is set as the lower limit. When the level detection device 4 detects the detection output, each of the rotary disks 5 and 6 of each measuring device starts to rotate and starts measuring and discharging the material as described above. When the upper limit level detection device 3 detects the limit level, the rotating disk 8 is stopped based on its detection output, and feeding of the material into the cylindrical chute 1 is stopped.

In each measuring device constructed as described above, in order to color the plastic to be extruded in a desired color, a concentrated color masterbatch is put into the color masterbatch measuring device 5, and a base pellet of colorless plastic is added to the color masterbatch measuring device 5. are placed in the base pellet measuring device 6, and each of the rotary disks 8 provided in each of the measuring devices 5 and 6 is rotated as described above to measure a predetermined amount of the color master batch and the base pellet, respectively, and a transparent cylindrical chute 1 is obtained. to be sent within.

Reference numeral 11 in the figure is a color masterbatch fed into the transparent cylindrical chute 1 as described above, and 12 is a base pellet. As shown in the figure, these two are alternately layered and overlapped in the transparent cylindrical chute 1, with the base pellet 12 having a thickness of a+b and the color masterbatch 11 having a thickness of b. In the figure, the color masterbatch 11 is shown as round pellets in the area b, and the base pellets 12 are shown as dots in the area a, but the color masterbatch measuring device 5 and the base pellet measuring device 6 are operated simultaneously. In addition to color master batch 11, base pellet 1 is placed in area b.
2 will be in a mixed state. In addition, each measuring instrument 5, 6
may be operated separately and alternately to prevent the base pellets 12 from being mixed in the area b of the colored matterbatch 11.

The mixing ratio of color masterbatch and base pellets is selected appropriately depending on the color density of the plastic to be extruded, but for example, if the amount of color masterbatch is 1 and the amount of base pellets is 1,
20, and in order to do this, for example, the measuring holes provided in the rotating disk of the color matsturbatch measurer 5 described above are equal to the total volume that accommodates the material at one time, and the measuring hole provided in the rotating disk of the base pellet measurer 6 is The metering holes form a ratio of 1:20 to the total volume that accommodates the material at one time. In order to double the mixing ratio of this color masterbatch, either the diameter of the measuring hole provided in the rotating disk of the color masterbatch measuring device 5 is increased to double its volume, or the measuring hole provided in the rotating disk of the color masterbatch measuring device 5 is increased in diameter. Just double the number of holes.

As mentioned above, the color master batches 11 and base pellets 12, which are alternately layered and overlapped in the transparent cylindrical chute 1, are fed into the extrusion screw part A in an alternating layered state and are uniformly kneaded. A colored plastic with a desired density and no uneven color is extruded from extrusion head B.

When the amount of material in the transparent cylindrical chute 1 decreases due to the extrusion and the level drops to the allowable lower limit amount, the lower limit level detection device 4 detects this, and the color master batch measuring device 5 uses the detection output.
The rotating disks 8 of the base pellet measuring device 6 start and rotate to measure and feed the color master batch 11 and base pellet 12 into the cylindrical chute 1. Also, the amount of material fed into the cylindrical chute 1 increases. When the level rises to the allowable upper limit amount and the upper limit level detection device 3 detects this, the detection output causes the rotating disks 8 of the color master batch scale 5 and the base pellet scale 6 to stop, and the cylindrical chute 1 This will stop feeding material inside.

In order to uniformly knead the color masterbatch 11 and base pellet 12 and extrude the colored plastic without uneven color as described above, the diameter of the cylindrical chute 1 should be dS, and the diameter of the cylinder in the extrusion screw section A should be If the inner diameter is dC and the maximum dimension of the pellet is dP, it is desirable that dS≦50dP and dS≦dC. This is the color master batch 11 in the cylindrical chute 1.
This is the limit at which the appropriate layered state of the base pellets 12 does not change to an inappropriate state due to differences in fluidity between the two, and if this limit is exceeded, variations in the hue of the extruded colored plastic will occur. In addition, the number of layers formed by the area a+b shown in the figure where the color master batch 11 and base pellet 12 overlap in the cylindrical chute 1 is about 5 layers in order to prevent the above-mentioned variation in hue. It is optimal and should be kept below 10 layers. Therefore, the height of L of the illustrated cylindrical chute 1 is L≦
10(a+b). Each of the above-mentioned measuring instruments 5 and 6
The diameter and length of the metering hole 9 provided in the rotating disk 8 may be within the range of (5 to 10) dP,
In practical terms, it may be more than this.

In the above embodiment, the cylindrical chute 1 is made transparent and the upper and lower limit level detection devices 3 and 4 are used as photo switches to detect the level of the material inside through the transparent wall of the cylindrical chute 1. However, this level detection device is not limited to a photo switch, but may be any suitable device that can detect the level of the material inside the cylindrical chute 1 without interfering with the flow of the material.

In order to change the color of the extruded plastic as described above, the color master batch in the color master batch meter 5 is of the desired color and fed to the cylindrical chute 1. The color master batch measuring device 5 can include a plurality of measuring devices each containing a color master batch for each color to be colored. When changing the coloring, the extruder continues to operate without stopping, and the color master batch meter that was previously in operation is stopped and another color master batch containing the desired color is replaced. You can change the coloring simply by operating the scale.

[Effects of the Invention] As described above, the present invention provides a color master batch measuring device and a base pellet measuring device in a cylindrical chute, and communicates this cylindrical chute with an extrusion screw portion, and the material inside the circular chute is An upper limit level detection device and a lower limit level detection device were installed, and each of the measuring instruments was started and stopped by the detection output of each of the level detection devices.
To change the color of the extruded plastic, simply change the operating color master batch scale.
Since there is no need to stop and clean the extruder for a long period of time as in the past, it is possible to achieve continuous color changes, which was difficult with conventional equipment, and the operating rate of the extruder can be improved. can be improved and productivity can be increased.

In addition, the cylindrical chute does not have stirring blades inside like conventional ones, and the material is not stirred inside the cylindrical chute. When changing the coloring of extruded plastic, color mixing with the previous material does not occur, and there is no need to stop the operation of the extruder for a long time to clean the inside of the cylindrical chute.

[Brief explanation of the drawing]

FIG. 1 is a diagram showing one embodiment of the present invention, FIG. 2 is a diagram showing a measuring device thereof, and FIG. 3 is a diagram showing a conventional device. 1: Cylindrical chute, 3: Upper limit level detection device,
4: Lower limit level detection device, 5: Color master batch measuring device, 6: Base pellet measuring device, A: Extrusion screw section.

Claims (1)

[Claims] 1. A measuring device for measuring and feeding the color masterbatch material and a measuring device for measuring and feeding the base pellet material are installed above a cylindrical chute whose lower end communicates with the extrusion screw part, and a measuring device for measuring and feeding the base pellet material is installed in the cylindrical chute. An upper limit level detection device for detecting the upper limit level of the material and a lower limit level detection device for detecting the lower limit level are installed, the measuring instrument is started by the detection output of the lower limit level detection device, and the detection output of the upper limit level detection device is A material feeding device for a plastic extruder, characterized in that the measuring device is stopped by: