JPH0124044B2 - - Google Patents

Description

[Detailed Description of the Invention] (a) Field of the Invention This invention melts various resin materials supplied to a resin molding machine that molds various synthetic resin products and cuts them into pellets. This invention relates to a resin pellet manufacturing device.

(B) Background of the Invention Processing methods commonly used in resin pellet manufacturing equipment include sheet cut method, strand cut method, aerial hot cut method, underwater hot cut method, etc. Each processing method depends on the melting point of the resin being processed. Or it is limited because of its physical properties.

The sheet cutting method can be applied to most resins, but it is a processing method in which the molten resin is flattened with a roll and then cut vertically and laterally with a cutter, so the processing efficiency is low and it is not suitable for mass production.

In the strand cut method, molten resin is extruded into a linear shape through a die, passed through a cooling bath, cooled and hardened, and then cut with a cutting machine. However, with this method, the cooling tank is long because the linear resin passes through it, increasing the installation area of the device.Also, because the linear resin is pulled out longer than the die, the linear resin may be cut during processing. However, there were some problems with the workability.

The aerial hot cut method is a processing method in which molten resin is extruded in a linear shape from a die, and the extruded resin is cooled by blowing cooling air while cutting with a cutter facing the die. With a low viscosity resin such as, the resin will not stick to the cutter or die even during aerial cutting, and the pellets will not overlap and fuse together even after cutting. Furthermore, this method is effective for resins whose physical properties change or even dissolve due to moisture, such as polyvinyl alcohol resins.

However, resins such as polyethylene and polypropylene have a relatively high viscosity in the molten state, so the cut pellets will stick to the die or cutter, making it difficult to cut, and in the worst case, cutting will not be possible. , not suitable for aerial hot cut method.

Underwater hot-cutting is a processing method in which molten resin is extruded into high-temperature cooling water using a die, and cut with a cutter facing the die while being cooled by the cooling water.
Even if the resin has a high melt viscosity, the cooling water prevents the cut pellets from adhering to the die or cutter, so cutting becomes difficult or impossible as with the aerial hot cut method.

However, this method requires constant circulation of high-temperature cooling water within the casing at the front of the die.
It requires a large amount of hot water and requires large-scale equipment.

In the jet hot cut method, a hot water jet nozzle 2 is installed on either or both of the die 8 and the cutter 36.
Cooling hot water mixed with air is jetted from the nozzles 29 and 37 to cut the linear resin into pellets.

This cooling hot water is extremely small compared to the above-mentioned underwater hot cut method, making it more efficient and requiring smaller equipment.

However, depending on the type of resin, for example, some resins with low melt viscosity such as polypropylene cannot be completely cut.

As explained above, in order to produce pellets using resins having different melt viscosities and physical properties, different means are required, and as a result, a dedicated machine suitable for the resins has conventionally been required.

(c) Purpose of the Invention The purpose of the present invention is to provide a resin pellet manufacturing apparatus that allows a single apparatus to arbitrarily select the most suitable processing method for each resin having different melt viscosity and physical properties.

(d) Structure of the Invention This invention is characterized in that a die having a mold hole for forming resin into a linear shape is attached to the head of an extruder, and a cutter for cutting the extruded resin into pellets is provided on the side facing the die. In the resin pellet manufacturing apparatus, the die and the cutter are covered with a casing body, communication holes are formed in the casing body at positions facing each other with the die and the cutter in between, and a cover and a cooling Installing pipes to connect fluids such as hot water and air,
It is selectably provided to correspond to multiple cutting methods such as an underwater cutting method, an aerial cutting method, and a jet cutting method, and the cutting portion of the die and cutter is provided with:
The resin pellet manufacturing apparatus is characterized in that a nozzle is formed on the cutting part side to set a jetting direction and to control jetting of fluid such as cooled hot water or compressed air in accordance with selection of the plurality of cutting methods.

(E) Functions and Effects of the Invention The present invention achieves the following by selecting the attachment of the lid and the pipe to the communication hole of the casing body, and selecting the fluid jetting control for the nozzle of the cutting part.
By forcibly supplying cooling hot water to the casing body, an underwater cut method can be obtained, and by forcibly supplying cooling air to the casing body, an aerial cut method can be obtained.
A jet cut method can be obtained by ejecting cooling fluid to the cut portion, and a composite cut method can be obtained by combining these methods.

As a result of the above, according to the present invention, by simply changing the supply of the cooling medium without changing the structure of the device, it is possible to obtain various cutting methods optimal for the resin used to produce pellets using one device. This eliminates the need for a dedicated machine for each resin as in the past, which is economical, and requires a smaller installation area than when a dedicated machine is provided.

(F) Embodiment An embodiment of the present invention will be described in detail below based on the drawings.

The resin pellet manufacturing device 1 is located at the head 3 of an extruder 2.
The extruder 2 has a well-known structure consisting of a cylinder 4 and a screw 5.

A die 8 formed by joining two discs 6 and 7 is attached to the front surface of the head 3, and this die 8 extrudes the resin into a linear shape as will be described later.
Further, a casing body 9 whose upper and lower ends are open is fixed to the front surface of the die 8, and within this casing body 9, a linear resin cutting means and a cooling means, which will be described later, are constructed.

The end of a cutter rotating shaft 10 constituting the cutting means is protruded from the front surface of the casing body 9 described above so as to maintain airtightness with the casing main body 9, and a sprocket gear 11 is attached to the end of the rotating shaft 10. is fixed.

Communication holes 9a, 9 are provided at the upper and lower ends of the casing body 9.
b, and a casing lower cover 12 is formed in these communication holes.
The casing top cover 13 is removable and arranged to maintain airtightness. In addition, depending on the cutting method described above, a pipe 51 connected to a hot water supply means (not shown) is connected to the casing lower lid 12 in order to circulate cooling hot water inside the casing body 9 in the underwater hot cut method, and a pipe 51 is connected to the casing lower lid 12 in order to circulate hot water for cooling inside the casing body 9. In the case of this method, the pipe 51 is removed and the cut resin pellets are dropped into the water tank below.

The same applies to the casing top lid 13. In the case of the underwater cut method, a drainage pipe 52 is connected to discharge hot water mixed with resin pellets and conveyed to a dehydrator (not shown), and in the case of the aerial cut method, an air pipe from the blower 53 is connected. Connect 54. In the hot water spout cut method, the upper communication hole 9a of the casing body 9 is closed with a lid.

A support stand 14 is fixed to the upper front surface of the casing body 9, and the motor 1 is mounted on this support stand 14.
A chain 18 is stretched between the sprocket gear 17 fixed to the output shaft 16 of the cutter 5 and the sprocket gear 11 of the aforementioned rotating shaft 10, and the motor 15 rotates the cutter rotating shaft 10 at a predetermined position. Drive in the direction of.

A double pipe-shaped support shaft 19 that also serves as a bearing for the shaft 10 is protruded from the center of the cutter rotating shaft 10 described above, and a pipe joint 20 is fixed to the shaft end of this support shaft 19. The pipe joint 20 includes a die side pipe 21 that supplies a cooling medium to the die 8 side,
Cutter side pipe 22 that supplies to the cutter side described later
are connected.

Note that the spring 23 urges the cutter toward the die 8 side.

The disks 6 and 7 constituting the aforementioned die 8 have a mold hole 24 that passes through them in a joined state, and this mold hole 24 is formed by molding resin into a line and forming a predetermined area excluding the center and outer periphery. A large number are formed within the circumferential range of .

The disk 6 is a heating side for maintaining resin flow, and has embedded holes 25 formed in radial positions along the mold holes 24 described above, and a sheathed heater 26 for heating is embedded in these holes. .

The disk 7 described above is a cooling side for cooling the linear resin, and has conductive passages 27 formed in radial positions sewing the mold holes 24 described above, and each passage 27 forms a circumference at the center side. It communicates with a supply passage 28 formed in a shape. Further, each of the conductive paths 27 communicates with die-side nozzles 29 formed in radial rows on the outer surface of the disk 7.

The inner end of a support shaft 19 is fixed to the front surface of the center of the die 8 consisting of the aforementioned disks 6 and 7 with a screw.
This support shaft 19 has a die-side cooling passage 31 and a cutter-side cooling passage 32 formed by the interior of the tube 30, and the end of the die-side cooling passage 31 is formed by a conduit passage 33 bored in the radial direction. The aforementioned supply passage 28
is connected to. The die-side cooling passage 31 is connected to the die-side pipe 21 described above.

The aforementioned cutter rotating shaft 10 is supported on the outer periphery of the support shaft 19 by bearings 34, 34, and a disc-shaped cutter block 35 is fixed to the inner end of the rotating shaft 10.
The center of the cutter block 35 and the outer periphery of the support shaft 19 are in sliding contact to maintain airtightness.

Cutters 36 are implanted on the inner surface of the cutter block 35 at four radial positions corresponding to the circumferential range of the die holes 24 of the die 8. This contact pressure is applied by the spring 23 described above.

Each cutter 36 described above is provided with a plurality of cutter-side nozzles 37 in a row that are open in the direction of rotation thereof, and the inner ends of the nozzles 37 connect to the inside of the cutter 36 and the conductive path formed in the cutter block 35. 38
..., and this conduction path 38 ... is a supply path 39 formed circumferentially in the stop part of the cutter block 35.
It communicates with

The inner end of the cutter side cooling passage 32 of the support shaft 19 communicates with the above-mentioned supply passage 39 via the conduction passage 40, and the outer end communicates with the above-mentioned cutter side pipe 22.

A cooling pipe 41 is connected to the die-side pipe 21 and the cutter-side pipe 22, which cools the cylinder 4 and supplies cooled hot water whose temperature has increased. A regulating valve 43 for regulating the pressurizing force of the compressed cooling hot water, a compressor 44 for mixing compressed air, and a regulating valve 45 for regulating the compressed air pressure are provided.

Furthermore, the aforementioned cooling pipe 41 has a drainage regulating valve 4.
6, Drain on/off valve 47, die side pipe adjustment valve 4
8. The drainage adjustment valves 46 each provided with a cutter side pipe adjustment valve 49 branch the excess water of the supplied cooling hot water to the drainage pipe 50 and drain it when the amount of cooling hot water to be used is very small. The drain opening/closing valve 47 is
When the resin pellet manufacturing apparatus 1 manufactures pellets by the aerial hot cutting method or the underwater hot cutting method, it is closed to stop the water supply to the die side pipe 21 and the cutter side pipe 22, and discharge the cooled hot water to the drain pipe 50. .

The die-side pipe adjustment valve 48 and the cutter-side pipe adjustment valve 49 adjust the supply amount of the mixed cooling fluid of cooling hot water and compressed air to the die-side nozzle 29 and the cutter-side nozzle 37.
Or stop it.

A method for manufacturing pellets using the resin pellet manufacturing apparatus 1 configured as described above will be described in detail.

When producing resin pellets such as hard vinyl chloride using the aerial hot cut method, the drain on/off valve 47
is closed, and the cooled hot water flowing through the cooling pipe 41 is guided to the drain pipe 50 and drained.

In addition, the casing lower lid 12 is connected to the upper and lower communication holes 9a and 9b of the casing body 9 of the resin pellet manufacturing apparatus 1.
and a casing upper lid 13 are attached to the casing upper lid 13, and an air pipe 54 connected to a blower 53 is connected to the casing upper lid 13 to forcibly supply cooling air into the casing body 9, and the linear resin extruded from the die 8 is passed through the cutter 36. and discharge it from the lower communication hole 9b.

When producing resin pellets by the underwater hot cut method, the drain on-off valve 47 is closed as in the above-mentioned aerial hot cut method, and the upper and lower communication holes 9a, 9b of the casing body 9 of the resin pellet manufacturing apparatus 1 are closed.
casing lower lid 12 and casing upper lid 13
are installed respectively, and a pipe 51 connected to an appropriate cooling/hot water supply means is connected to the casing lower lid 12.
Furthermore, a drainage pipe 52 connected to a suitable dehydrator at one end is connected to the casing upper lid 13.

Then, pressurized cooling hot water is forcibly supplied into the casing body 9 to cool the linear resin extruded from the die 8, while the cutter 3 is installed opposite to the front surface of the linear resin.
6, and guide the cut pellets together with the cooled hot water from the drain pipe 52 to the dehydrator,
Dry and collect pellets.

When producing resin pellets of nylon, polyester, polypropylene, etc. using the hot water jet hot cut method, the upper communicating hole 9a of the casing body 9 of the resin pellet producing apparatus 1 is closed with a suitable lid. In addition, the drain on-off valve 47 is opened, the supplied cooling hot water is pressurized by the pressurizing pump 42, and the mixed cooling fluid obtained by mixing compressed air with the pressurized cooling hot water by the compressor 44 is transferred to the die side pipe 2.
1 and the cutter side pipe 22.

The mixing ratio of the mixed cooling fluid is adjusted according to the characteristics of the resin to be manufactured by the regulating valve 43 of the pressurizing pump 42 and the regulating valve 45 of the compressor 44, and further by the die-side pipe regulating valve 48 and the cutter-side pipe regulating valve 49. Adjust the amount of mixed cooling fluid ejected.

The above-mentioned adjusted mixed cooling fluid is supplied to the die-side nozzle 29 via the die-side cooling passage 31 and to the cutter-side nozzle 37 via the cutter-side cooling passage 32, and is then supplied to the cutter-side nozzle 37 via the die-side cooling passage 31 and cutter by the die 8 and the cutter 36. It is ejected from these nozzles 29 and 37.

By driving the motor 15, the cutter rotation 10 is rotated, and the cutter 36 is rotated in the cutting direction. When the extruder 2 extrudes the resin in this state,
The resin is formed into a linear shape and extruded through the mold holes 24 of the die 8, and the cutters 36 cut the linear resin into pellets.

During this cutting, the resin is cooled by the mixed cooling fluid ejected from both nozzles 29 and 37, and the disk 7 of the die 8 is also cooled by each conduction path 27, so the resin is cooled to a temperature suitable for cutting. be done.

Note that the heat conductivity of the mixed cooling fluid, i.e., air bubbles, is significantly lower than that of the cooling water. As a result, the temperature rise can be suppressed and the appropriate cooling temperature set for the mixed cooling fluid can be maintained, and the cooling effect can be significantly enhanced.

The cut resin pellets are then discharged from the lower communicating hole 9b of the casing body 9 together with the mixed cooling fluid.

In the above embodiment, the mixed cooling fluid of air was ejected from both the die side nozzle 29 and the cutter side nozzle 37, but since this device 1 has a high cooling effect, it can be applied to the type of resin used to produce pellets. It is possible to selectively use the mixed cooling fluid from one of the nozzles 29 or 37 and only cooling water from the other, and also adjust the amount of air mixed into the mixed cooling fluid.

As detailed above, according to the resin pellet manufacturing apparatus of the present invention, it is possible to manufacture resin pellets by selecting the optimal method according to various resins with different melt viscosities and physical properties with one apparatus, thereby reducing the installation area and reducing capital investment. Funding will also be reduced.

[Brief explanation of drawings]

FIG. 1 is a side view of the resin pellet manufacturing apparatus. Second
The figure is an enlarged sectional view of the main part of FIG. FIG. 3 is a sectional view taken along the line AA in FIG. 2. Figure 4 is B-B in Figure 2.
Linear cross-sectional view. FIG. 5 is a side view of a resin pellet manufacturing apparatus including an extruder. 1... Resin pellet manufacturing device, 2... Extruder,
8...Dice, 9...Casing body, 9a, 9
b... Upper and lower communication holes of the casing body, 12... Casing lower cover, 13... Casing upper cover, 36...
...Cutter.

Claims (1)

[Claims] 1. A die 8 having a mold hole 24 for forming resin into a linear shape is attached to the head 3 of the extruder 2, and a cutter for cutting the extruded resin into pellets on the side facing the die 8. 36, the die 8 and the cutter 36 are covered with a casing body 9, and communicating holes 9a and 9b are provided in the casing body 9 at opposing positions with the die 8 and the cutter 36 in between, respectively. These communication holes 9a and 9b are connected to lids 12 and 13, and pipes 5 for connecting fluids such as cooling hot water and air.
1, 52, and 54 are selectively installed in accordance with multiple cutting methods such as an underwater cutting method, an aerial cutting method, and a jet cutting method, and the cutting portions of the die 8 and the cutter 36 are provided with:
a nozzle 29 or 37 for controlling the jetting of fluid such as cooling hot water or compressed air by setting a spouting direction on the cutting section side and selectively corresponding to the plurality of cutting methods;
A resin pellet production device that formed