JPH0410407B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a master batch method, which is one of the methods for blending additives into thermoplastic resin molded products using a molding machine such as an injection molding machine or an extrusion molding machine. The present invention relates to a master batch supply device used in the above system.

The masterbatch referred to in the present invention refers to a material in which additives such as colorants, stabilizers, antistatic agents, and flame retardants are dispersed in a thermoplastic resin at a high concentration, and is mainly in the form of pellets. say. In the masterbatch method, a predetermined amount of masterbatch is mixed with natural resin (a pellet-shaped molding resin material that does not contain the above additives), and the resin is kneaded and plasticized in a molding machine, at the same time the additives in the masterbatch are dispersed. This is a method for obtaining molded products.

Traditionally, the mixing process using the master batch method was
The natural resin and masterbatch were mixed in batches using a mixer such as a tumbler or a Henschel mixer, and then the mixture was charged into a hopper of a molding machine. However, in such batch mixing, it takes several hours to clean the mixer used in the mixing method when changing product types or colors, which is a major hindrance to the flow of the process. Moreover, the installation area had to be increased, and the energy consumption of the mixer was large. Furthermore, the natural resin and masterbatch are separated from each other due to vibrations in the hopper of the molding machine and static electricity caused by material flow, making it impossible to obtain a final molded product in which additives are uniformly blended. However, despite these drawbacks, it is often used in small lot molding due to its simplicity.

As an improvement to the above-mentioned batch mixing method, automation of measuring and mixing is progressing, and various methods have been put into practical use. To explain the currently employed equipment with drawings, for example, as shown in Figure 1, a molding machine 1
A device in which a mixer 2 is provided on the raw material supply port of the machine, and the mixer 2 is separately equipped with a natural resin quantitative feeder 3 and a masterbatch quantitative feeder 4, or as shown in FIG. An apparatus is known in which a mixer 2, a masterbatch quantitative feeder 4, and a natural resin quantitative feeder 3 are sequentially stacked one on top of the other. However, all of these devices are batch type and are built on top of the molding machine, which makes disassembly and cleaning very troublesome, and it is also difficult to prevent separation inside the hopper of the molding machine as described above. I can't.

In addition, a masterbatch quantitative feeder 4 as shown in Fig. 3 is provided on the molding machine 1, and the masterbatch is quantitatively supplied to the raw material supply section of the molding machine, and the natural resin is supplied from a separately provided hopper 6 of the molding machine. A device for mixing the masterbatch with the molding machine is also known, but this method is also inconvenient to disassemble and clean because the device is built into the molding machine, and it requires manual labor or dedicated equipment to feed the masterbatch to the masterbatch metering machine. It is necessary to incorporate the following equipment. In addition, when the masterbatch metering method is capacitive, it cannot detect if the masterbatch is a pellet mistake or is not being supplied for some reason, and it cannot respond to changes in the bulk density of the masterbatch. By using a gravimetric method for measuring the masterbatch, the disadvantages in measurement can be overcome, but incorporating a new device on the molding machine makes the device even more complicated, which adds to the complexity of disassembly and cleaning.

The present invention was made as a result of intensive research to overcome the problems in the automatic supply of master batches as described above. That is, the first invention has a mechanism that measures a predetermined amount of masterbatch supplied from a masterbatch storage hopper and automatically controls the supply amount, and mechanically controls the supplied masterbatch in conjunction with the operation of a molding machine. a quantitative transport device comprising means for transporting, an air-solid separator disposed above the molding machine, an air conveyor for transporting the masterbatch transported from the quantitative transport device to the air-solid separator, and the above-mentioned A mixer for substantially uniformly mixing the masterbatch separated by the air-solid separator with the molding resin material that is being supplied from the raw material supply section of the molding machine by continuously dropping it onto the molding resin material being supplied from the raw material supply section of the molding machine. A second invention is an automatic masterbatch supplying device comprising a plurality of masterbatch storage hoppers, the number of which is equal to the number of masterbatch storage hoppers, and which measures and supplies a predetermined amount of masterbatch supplied from one of the plurality of storage hoppers. A metering transport device equipped with a mechanism for automatically controlling the amount and a means for mechanically transporting the supplied masterbatch in conjunction with the operation of the molding machine, and an air-solid separator disposed above the molding machine. , an air conveying machine that transports the masterbatch transported by the quantitative transport device to the air-solid separator, and the masterbatch separated by the air-solid separator is being supplied to the raw material supply section of the molding machine. A switch mechanism is provided for operating a mixer for substantially uniformly mixing the molded resin material with the molded resin material by continuously dropping the mixture onto the molded resin material, and any one of the plurality of metered volume transporters. This is an automatic master batch supply device.

An object of the present invention is to provide an automatic master batch feeding device that minimizes the time and effort required for cleaning the device when changing the type or color of master batches, and is extremely economically advantageous even in high-mix, low-volume production. There is a particular thing. Another purpose is that even if the masterbatch is continuously supplied, the natural resin and masterbatch will not separate in the hopper of the molding machine, so molded products with fewer defects and excellent quality stability. The present invention provides an automatic master batch supplying device that makes it possible to obtain a master batch.

Hereinafter, the present invention will be explained based on the drawings.

FIG. 4 and FIG. 5 are drawings showing an embodiment of the present invention, in which a quantitative transport device 8 and a pneumatic conveyor 9 are shown.
, a cyclone 10, and a mixer 11 for uniformly mixing the masterbatch and molding resin material. In this embodiment, the control panel 1 of the device of the present invention
A master batch storage hopper 7, quantitative transport device 8, and pneumatic conveyor 9 are installed on the loading platform of a special caster 13 equipped with 2, so that the main body of the automatic feeding device can freely move on the floor. below,
This will be explained using FIG.

The storage hopper 7 is fixed on the loading platform of the caster 13 by a support 14, and is provided with a cut-gate type supply mechanism 15 interlocking with the quantitative transport device 8 at the discharge port.

The quantitative transport device 8 is disposed below the storage hopper 7, and includes a mechanism 16 for measuring the weight of the masterbatch supplied from the storage hopper 7, a circuit means for exchanging the measured value into an electric signal, and opening and closing the cut gate. Spring feeder 17 and power 18
and circuit means for controlling the amount of master batch transported. The operation of the spring feeder 17 depends on the type of molding machine. For example, if the molding machine is an extrusion molding machine, it is fed continuously, and if the molding machine is an injection molding machine, it is fed intermittently in conjunction with the operation of the molding machine. The rotational speed of the spring feeder 17 is controlled based on the rate of reduction of the masterbatch, and a fixed amount is supplied. The master batch may be supplied from the storage hopper 7 to the quantitative transport device 8 by other means, such as a screw feeder, rotary feeder, pneumatic transport, etc., in addition to the cut gate used in this embodiment. In addition to the gravimetric method, it is also possible to adopt a capacitive method for measuring the masterbatch, but the capacitive measuring method is useful when it is not possible to cope with changes in the density of the master batch due to product changes or color changes. Therefore, a gravimetric measurement method is preferable.
In addition to the spring feeder used in this embodiment, screw feeders, table feeders, etc. can also be used as mechanical transport means provided in the quantitative transport device 8, but from the viewpoint of cleaning and ease of handling, Spring feeders are preferred.

The air conveyance machine 9 has a pipe 19 and a quantitative conveyance device 8.
Piping 19 receives the masterbatch transported from
It consists of a hopper 20 and an ejector mechanism 21. The ejector mechanism 21 is a mechanism that uses compressed air supplied from a compressor (not shown) to suck air into the pipe 19 and eject it. There is a rider. In the present invention, a blower used in a general pneumatic conveyor may be used without attaching an ejector mechanism. However, when using a blower, the normal shape, which is considered to have the largest true specific gravity (2 g/cm ² ),
To transport masterbatch pellets of the same size (3 mm diameter, 3 mm length) by 3 m horizontally and 2 m vertically, it takes 20~
A 0.4-0.7KW blower is required for an 80mm diameter pipe, and the space required for the blower equipment is also quite large. However, according to the ejector mechanism described above, the power consumption is about 0.4KW and the equipment space is small. If the diameter is about 1/50th, and the pipe diameter is 20mm, it will have the same transport capacity.

The cyclone 10 is integrated with the mixer 11,
It is arranged and detachably fixed on the molding machine 25, and has an inlet 22 for air and the masterbatch conveyed by the air on the side, an air outlet 23 at the upper part, and a droplet 24 for the masterbatch separated from the air at the lower part. The size of the cyclone 10 is quite small when using a normal master batch. For example, when the diameter of the pipe 19 is 20 mm, separation is theoretically possible with a diameter of 53 mm and a height of 160 mm. but,
If it is too small, it will be inconvenient to clean, so it is practically designed to be larger than the above value. The air-solids separator that separates the air-borne masterbatch from the air does not use a cyclone, but other means may be used, When introduced into the hopper of a molding machine, the masterbatch flies around inside the mixer 11 and is not uniformly mixed with the molding material.

The mixer 11 is made by connecting two cylinders with different diameters; one end of the small cylinder is connected to the masterbatch drop port 24, and one end of the large cylinder is connected to the bottom of the hopper 26 of the molding machine 25. It is attached.

FIG. 5 is a diagram schematically explaining the movement of pellets in the mixer 11 of FIG. The natural resin 29 and masterbatch 28 are uniformly mixed while falling onto the resin 29 and moving to the supply port 27 within the mixer 11. As shown in Fig. 5, if the diameters of the large and small cylinders of the mixer 11 are Aφ and Bφ, and the diameter of the discharge port of the hopper 20 is Cφ, then when the blending ratio of the masterbatch to natural resin is 5/100, Aφ/Cφ >1/
5, preferably >1/4 is required, and when the above blending ratio is 3/100, Aφ/Cφ>1/7, preferably >1/5 is required. Further, considering the ease of handling the device, it is preferable that Aφ>Bφ.

FIG. 6 shows a second embodiment using a mixer 30 having a different shape from that of the embodiment shown in FIG. In the second embodiment, the process from the masterbatch storage hopper to the cyclone is the same as in the first embodiment, and the drawings are omitted. The mixer 30 has a shape in which a cylinder and a cone are connected, and the upper cylindrical part is connected to the cyclone 10.
The master batch is connected to the master batch drop port 24 and charged into the hopper 31 of the molding machine, and the other end is fixed to the lower inner surface of the hopper 31 with a member 31.
The master batch 28 that has fallen inside the mixer 30 is
It is mixed with the natural resin 29 at the opening 33 and transferred to the raw material supply port 27 . When the mixer 30 is used, there is an advantage that a hopper having a shape normally used in a molding machine can be used as is. Letting the diameters of the portions shown in FIG. 6 be Aφ and Cφ, respectively, the same equation as the above-mentioned equation holds true here as well. However, Aφ
Aφ must be large enough to not obstruct the flow of natural resin entering the molding machine relative to Cφ, and this is also related to the throughput of the molding machine, but in reality Aφ is 1/3 of Cφ.
It is sufficient to know the upper limit of Aφ, and there is no need to know the upper limit of Aφ.
In addition to the conical shape, the lower part of the mixer 30 may have a cylindrical shape or a polygonal prism having the same area of Aφ.

FIG. 7 shows five masterbatch storage hoppers 34, 35, 36, 37, 38 and five mass transfer devices 39, 4 under each storage hopper.
FIG. 4 is a conceptual diagram of a third embodiment using 0, 41, 42, and 43. Different types of masterbatches are stored in each storage hopper, and any masterbatch can be introduced into the pneumatic conveyance machine 44 by switching a switch on the quantitative transfer device. The masterbatch conveyed by the pneumatic conveyor 44 passes through a cyclone 45 and a mixer 46, is mixed with natural resin, and is supplied to a molding machine 47.

In the present invention, the quantitatively measured masterbatch is supplied to the hopper of the molding machine by air conveyance.
There is no need to place the masterbatch storage hopper and quantitative transport device on top of the molding machine, and they can be installed on the same floor as the molding machine or on movable casters, reducing the time and effort required to clean the equipment when changing masterbatch types. You can save a lot of time. In addition, by installing a pair of storage hoppers and a plurality of quantitative supply devices for master batches, it is possible to change master batch types extremely easily even in high-mix low-volume production, which greatly contributes to streamlining the process.

[Brief explanation of drawings]

FIG. 1, FIG. 2, and FIG. 3 are drawings showing conventional automatic feeding devices, respectively. 1... Molding machine, 2... Mixing machine, 3... Natural resin metering and feeding machine, 4... Master batch metering and feeding machine, 5... Hopper, 6... Hopper, 7...
...Load cell. FIG. 4 is a drawing showing a first embodiment of an automatic master batch supplying device of the present invention. 7...Storage hopper, 8...Quantity transport device, 9
...Air conveyor, 10...Cyclone, 11...
Mixer, 25... Molding machine, 26... Hopper. FIG. 5 is a sectional view of the mixer of the first embodiment, and FIG. 6 is a sectional view of the mixer of the second embodiment. FIG. 7 is a conceptual diagram of the third embodiment. 34-38...Storage hopper, 39-43...
Quantitative transport device, 44... pneumatic conveyor, 45... cyclone, 46... mixer, 47... molding machine.

Claims (1)

[Scope of Claims] 1. A mechanism for measuring a predetermined amount of masterbatch supplied from a masterbatch storage hopper and automatically controlling the supply amount, and mechanically transporting the supplied masterbatch in conjunction with the operation of a molding machine. an air-solid separator disposed above the molding machine, an air conveyor for transporting the masterbatch transported from the quantitative transport device to the air-solid separator, and the above-mentioned A mixer for substantially uniformly mixing the masterbatch separated by the air-solid separator with the molding resin material that is being supplied from the raw material supply section of the molding machine by continuously dropping it onto the molding resin material being supplied from the raw material supply section of the molding machine. An automatic master batch supply device that is equipped with a master batch. 2 The same number of storage hoppers for a plurality of master batches are provided, and a mechanism for measuring a predetermined amount of master batches supplied from one of the plurality of storage hoppers and automatically controlling the supply amount, and a molding machine for storing the supplied master batches. an air-solid separator disposed above the molding machine; The masterbatch separated by the air-solid separator is continuously dropped onto the molding resin material being supplied by the raw material supply section of the molding machine, so that the molded resin material and the molded resin material are substantially separated. An automatic master batch supply device comprising a mixer for uniformly mixing the batches and a switch mechanism for activating any one of the plurality of metered metering conveyors.