JPS61266207A - Dice for manufacturing resin pellet - Google Patents

Abstract

PURPOSE:To uniformize nozzle temperature, prevent generation of clogging and obtain the pellet of high quality by a method wherein a heating jacket, consisting of inside annular path, outside annular path and straight paths connecting both of inside and outside annular paths, is formed on the surface side of the dice. CONSTITUTION:In the dice for manufacturing resin pellet, the outside annular groove 22, the inside annular groove 23 and a multitude of straight line grooves 26, parallel thereto and provided therebetween, are provided while these annular grooves and straight grooves are covered by a hard plate 33 whereby the heating jacket is formed in the dice. Synthetic resin, kneaded in a molten condition, is pressurized and supplied to the back surface side of the nozzle 34, is extruded into cooling water from the surface side thereof and is cut into fine pieces by a rotary cutter. During this period, heating fluid or steam is introduced into the outside annular groove 22 through a heating fluid introducing path 30, is distributed into a multitude of straight grooves 26, 26 respectively, flows into the lower arced groove 22b and is discharged out of a heating fluid discharging path 31. Accordingly, resin extruding nozzles 34, provided between the straight grooves 26, are heated substantially uniformly on the whole surface of the dice 20.

Description

Detailed Description of the Invention (Industrial Application Field) The present invention relates to a die used in a resin pellet manufacturing apparatus for manufacturing synthetic resin pellets, and in particular to a heating jacket for heating a resin extrusion nozzle portion. The present invention relates to a die for manufacturing resin pellets, which is equipped with a die for producing resin pellets.

(Prior Art) Generally, synthetic resin materials are transported after being processed into pellets by kneading raw materials. Such resin pellets are
It is manufactured by continuously extruding kneaded molten synthetic resin from a nozzle and cutting it into small pieces with a rotating cutter. Therefore, a die equipped with a large number of resin extrusion nozzles is used in a resin pellet manufacturing apparatus for this purpose.

FIGS. 4 and 5 are a front view and a cross-sectional view of essential parts of an example of such a conventional die for producing resin pellets.

As is clear from these figures, the die main body l is a disc-shaped body in which an outer flange ring 3 and an inner flange ring 4 are welded to the outer and inner sides of the nozzle ring 2, respectively. Bolt holes 5,5. formed in the flange ring 3.4. ...and 6,6. It is fixed to the base of the resin pellet manufacturing apparatus by bolts inserted through... The nozzle part ring 2 has a number of nozzles 7.7.・・・
・is formed. As shown in FIG. 4, the nozzle 7.7. ... are arranged radially on the nozzle ring 2.

The surface 2a of the nozzle ring 2 is formed as a flat surface, and the die main body 1 is attached so that the surface 2a is substantially perpendicular. A hardened surface layer 8 with high wear resistance is provided on the surface 2a.
is provided, and the blade of the rotary cutter 9 is rotated along the surface 2a.

The synthetic resin in a molten state is supplied under pressure from the back side of the die body 1 to the back side of the nozzle ring 2, and is passed through the nozzles 7.7.・
It is continuously pushed out from... Then, the extruded string-like synthetic resin is cut into small pieces by a rotary cutter 9 and made into pellets.

By the way, the pellets produced in this way will weld together and become lumpy if left in a high temperature state. Therefore, normally, the surface side of the die body 1 is filled with cooling water, and the synthetic resin is extruded into the cooling water and is cured at the same time as it is cut by the cutter 9. In that case, the cooling water comes into contact with the surface of the die body l, and the surface 2a side of the nozzle ring 2 is cooled by the cooling water, so that the molten resin in the nozzle 7 hardens. In order to prevent the nozzle 7 from clogging, a heating jacket is provided around the nozzle 7, and a heating fluid such as steam is introduced into the jacket to heat the nozzle 7 portion.

Conventionally, such a heating jacket has an outer annular passage lO and an inner annular passage 11 provided on the outer circumferential surface and the inner circumferential surface of the nozzle ring 2, respectively, as shown in FIG. 4.5. , a large number of small holes 12, 12.11 connecting these annular passages 10.11. It was composed of... And the small holes 12, 12. ... are formed radially by drilling or electrical discharge machining from the outer peripheral surface side of the ring 2 through between each row of nozzles 7゜7, ... arranged radially in the nozzle part ring 2. Ta.

The outer annular passage IO is divided into a -L semicircular passage 10a and a lower semicircular passage 10b by partitions 13.13 provided on both sides in the horizontal direction. The semicircular passages 10a, 1 are located at the lower part of the die body l.
A heated fluid introduction passage 14 and a heated fluid discharge passage 15 are provided which communicate with each other.

In this way, the heating fluid such as steam introduced from the introduction passage 14 flows radially from the semicircular passage 10a of the outer annular passage 10 to the small holes 12, 12. . . into the inner annular passage 11 through the lower small holes 12, 12 . ... through the lower semicircular passage 10b through the discharge passage 15, while the nozzles 7.7. ...parts are heated. When a liquid such as high-temperature oil is used as the heating fluid, the heating fluid is made to flow in the opposite direction (see Japanese Patent Publication No. 51-32680).

(Problems to be Solved by the Invention) However, in such a die for producing resin pellets, there are an outer annular passage lO1, an inner annular passage II, and a large number of small holes 12, 12, . ..., the die body 1 is constituted by three rings 2゜3.4, and by welding them all around the ring, they are joined together in a sealed manner. There is a need to. Therefore, the number of parts increases, and the assembly layer T also requires time and effort. In addition, the work of forming a large number of small holes 12°12, etc. in a radial manner is complicated, and especially in large dies, the length of the small holes 12 becomes long, so the machining process is difficult. becomes extremely difficult. Furthermore, it is desirable that the small holes 12 be provided close to the surface 2a of the nozzle ring 2 in order to heat the nozzle 7 to its tip. Therefore, it is difficult to drill holes in such areas.

Furthermore, the heating fluid flows from the outer annular passage lO through a generally horizontal small hole 12, for example at the side of the die;
The flow from the inner annular passage 11 to the substantially horizontal small holes 12 is such that each small hole 12, 12 . It is difficult to obtain a uniform flow in the nozzle 7.7. There is a problem that not only is the heating of the die uneven depending on the part of the die, but also the internal resistance to flow becomes large, making it difficult to flow a large amount of heating fluid. Furthermore, when steam is used as the heating fluid, there is also the problem that condensate accumulates inside.

The present invention was made in view of these problems, and its purpose is to provide a die for producing resin pellets that is easy to process and in which a large number of resin extrusion nozzles are heated almost uniformly throughout. It's about getting.

Another object of the present invention is to heat the resin extrusion nozzle to a portion close to the die surface.

(Means for Solving the Problems) In order to achieve this object, the present invention comprises a die body made of one flat plate, and an outer annular groove and an inner annular groove are formed on the surface of the die body. A large number of parallel straight grooves in two downward directions are formed in the annular surface section defined by the outer and inner annular grooves, and these annular grooves and straight grooves are covered by an annular hard plate. The hard plate is integrated with the surface of the die body by diffusion welding. And -L of the outer annular groove
A heating fluid introduction passage communicating with the lower semicircular groove portion and a heating fluid discharge passage communicating with the lower semicircular groove portion are provided.

The resin extrusion nozzle is formed between each straight groove so as to penetrate through the die body and the hard plate.

(Function) In this way, by covering the outer annular groove, the inner annular groove, and a large number of straight grooves provided on the surface of the die body with the annular hard plate diffusion-welded to the surface, the outer A heating jacket consisting of an annular passage, an inner annular passage, and an inter-nozzle passage is now formed. Therefore, the die body only needs to be machined with an annular groove and a straight groove on its surface, and the process becomes easy.

The heating fluid introduced into the outer annular groove from the heating fluid introduction passage flows from one end of the straight groove to the outer annular groove at the other end, or from the straight groove to the inner annular groove and from the other straight groove to the outer annular groove. It flows into the groove and is discharged from the heated fluid discharge passage. At this time, since the heated fluid introduction passage and the discharge passage communicate with both ends of each straight groove formed downward, the flow thereof is also smooth. Therefore, the heating fluid is reliably distributed to both straight grooves, and each nozzle is heated evenly.

Moreover, since the straight groove is only covered by the hard plate, it is close to the die surface.

(Example) Hereinafter, the present invention will be explained in detail using the drawings.

In the drawings, Figures 1 to 3 show a die for producing resin pellets according to the present invention. Figure 1 is a partially cutaway front view of the die, Figure 2 is a longitudinal sectional view thereof, and Figure 3 is a It is an enlarged cross-sectional view.

As is clear from these figures, this die 20 has 1
The die main body 21 has a disk shape. The surface 21a of the die body 21 is a flat surface, and an outer annular groove 22 and an inner annular groove 23 that are concentric with the center axis of the die body 21 are formed on the surface 21a. A plurality of bolt holes 24 and 2 are provided outside the outer annular groove 22 and inside the inner annular groove 23, respectively.
4,...;25,25. ... is provided,
Bolts inserted through these bolt holes 24 and 25 allow the die 20 to be mounted in a substantially vertical position to a base body (not shown) of a resin pellet manufacturing apparatus.

The annular surface portion 21b of the die body 21 defined by the outer annular groove 22 and the inner annular groove 23 has a large number of mutually parallel linear grooves 26, 26, extending in the vertical direction. ... is formed.

i Both ends of this straight groove 26 are connected to the outer annular groove 22, or one end is connected to the outer annular groove 22 and the other end is connected to the inner annular groove 2.
3, they are connected to each other.

The outer annular groove 22 is divided into an upper semicircular groove and a lower semicircular groove by partitions 27.27 provided on both sides in the horizontal direction. ” The partially semicircular groove further includes a plurality of partitions 28, 28 . ..., a plurality of upper arcuate grooves 2
2a, 22a.

It is divided into... Further, the lower semicircular groove is divided into a pair of left and right lower arcuate grooves 22b, 22b by a partition 29 provided at the lower part. The die body 21 includes heating fluid introduction passages 30, 30, . ...
and heated fluid discharge passages 31.31 communicating with the lower arcuate grooves 22b, 22b, respectively. These heating fluid introduction passages 30 are located in each upper arcuate groove 22a.
Two parts, that is, near the 4th end of the straight groove 26 located on the center side, communicate with the upper arcuate groove 22a, respectively. Further, the heated fluid discharge passage 31 is connected to the lower arcuate groove 22b in the lower part of each lower arcuate groove 22b, that is, in the vicinity of the lower end of the straight groove 26 located in the center.
It communicates with 2b.

The inner annular groove 23 also has partitions 32 provided above and below it.
32 into a pair of left and right semicircular grooves.

These outer annular grooves 2 are formed on the surface 21a of the die body 21.
2. Inner annular groove 23 and annular surface portion 21b therebetween
An annular hard plate 33 that can cover the area is diffusion welded. This hard plate 33 is made of a wear-resistant and corrosion-resistant material, and a blade of a rotary cutter (not shown) rotates along its surface.

In this way, a heating jacket consisting of an inner annular passage, an outer annular passage, and a straight passage connecting them is formed on the surface side of the die 20.

A large number of resin extrusion nozzles 34, 34, . . . are located between the straight grooves 26, 26, . ... are arranged in a row. This nozzle 34 is connected to the die body 21
and a hard plate 33 in the axial direction, and as shown in FIG. 3, the back side has a large diameter part 34a, the front side has a small diameter part 34b, and a tapered part 34c is provided between them. There is. The straight groove 26 is deep enough to reach the tapered part 34c of the bulge, and the bottom surface 26a is deep enough to reach the tapered part 34c.
The slope corresponds to the slope of 4c.

In the resin pellet manufacturing die 20 configured as described above, the synthetic resin kneaded in a molten state is passed through the nozzle 34.
The material is supplied under pressure to the back side, pushed out from the front side into cooling water, and cut into small pieces by a rotating cutter.

During this time, steam, which is a heating fluid, flows into the heating fluid introduction passage 3.
0 to the outer annular groove 22 and divided by the partitions 27.28, a large number of straight grooves 26, 26, .
Each will be distributed to... And each straight groove 26.2
The steam guided to B, .
, 26 , .

In this way, the nozzles 34 , 34 , . . . provided between the straight grooves 26 , 26 , .
．． 26. It is heated by the steam flowing through... At this time, as described above, by making the bottom surface 26a of the straight groove 26 an inclined surface corresponding to the tapered part 34c of the nozzle 34, the straight groove 26 is deep enough to reach the tapered part 34c. The nozzle 34 has a small diameter portion 3
The area from the tapered portion 4b to the tapered portion 34c is effectively heated, and clogging thereof is reliably prevented. Moreover, since only the hard plate 33 is provided on the surface side of the straight groove 26, the nozzle 34 is reliably heated up to the vicinity of its tip.

The steam flows from -1- to the lower arcuate groove 22b from the inner arcuate groove 22a through the upper straight groove 26, the inner annular groove 23, and the lower straight groove 26, almost linearly from top to bottom. Since it flows, the flow becomes smooth and is reliably distributed to each straight groove 26.2B, . . . . Therefore, all nozzles 34 , 34
.

... is heated almost uniformly over the entire surface of the die 20. Moreover, even if drainage occurs inside, the drainage will not accumulate inside because each passage is formed in the vertical direction.

When manufacturing such a die 20 for producing resin pellets, first, an outer annular groove 22 and an inner annular groove 23 are formed on the surface 21a of the disk-shaped die body 21, and then a large number of straight grooves 26, 26, ... are formed at approximately equal intervals. Since these grooves 22, 23, and 26 can be formed by groove machining, the machining becomes extremely easy. In particular, since the straight grooves 26 1 , 26 , . . . are formed as straight grooves parallel to each other, even a large number of narrow grooves can be easily processed. Then, partition bodies 27 , 28 are formed in the outer annular groove 22 and the inner annular groove 23 by overlay welding or the like.

29 and 32 are provided.

Next, a heating fluid introduction passage 30 and a discharge passage 31 are formed in the die body 21 by drilling, and nozzles 34 , 34 , .
... by drilling or electrical discharge machining. Then, an annular hard plate 33 is diffusion-welded to the surface 21a of the die body 21. Finally, using the nozzle 34 formed on the die body 21 as a guide, the hard plate 33
Then, the tip of the nozzle 34 is bored by electrical discharge machining.

In this way, a die 20 as shown in FIGS. 1 to 3 can be obtained by simple processing. Its constituent parts are only one die body 21 and one hard plate 33, and parts management becomes easy.

The die 20 manufactured in this manner was attached to the base of a resin pellet manufacturing apparatus, and the surface temperature distribution under actual usage conditions was measured, and the temperature difference was within 1°C. This means that the surface temperature difference of conventional dies is 10 to 15 degrees Celsius.
This is extremely good compared to what it was. As a result, no clogging occurred in the nozzles 34, 34, . . . and high quality pellets could be obtained.

In addition, in the above embodiment, the heated fluid introduction passage 30 and the discharge passage 31 are each provided at a plurality of locations, but the number of these may be reduced. In particular, only one discharge passage 31 may be provided at the lowest part of the outer annular passage 22. In that case, the discharge passage 31 should have a large diameter.

Further, when high temperature oil or the like is used as the heating fluid, the introduction passage 30 and the upper semicircular groove are provided in the lower part, and the discharge passage 31 and the lower semicircular groove are provided in the upper part. Even in such cases.

The same effects as in the above embodiment can be obtained.

(Effects of the Invention) As is clear from the following explanation, according to the present invention, an outer annular groove and an inner annular groove are provided on the surface of a flat die body, and a large number of parallel linear grooves are provided between the outer annular groove and the inner annular groove. By providing a heating jacket and covering these annular grooves and linear grooves with a hard plate, a heating jacket is formed inside the die, which not only makes the processing extremely easy, but also allows parts to be easily processed. You can also reduce your points.

Furthermore, since the heating fluid introduction passage communicates with the outer annular groove at one end of the straight groove, and the discharge passage communicates with the outer annular groove at the other end of the straight groove,
The flow direction of the heating fluid is simplified to approximately one direction, thereby preventing drainage from accumulating inside, and allowing the heating fluid to flow approximately evenly through each straight groove. Therefore, the resin extrusion nozzle installed between the straight grooves is heated almost uniformly over the entire surface of the die. Moreover, since the passage for the heating fluid that heats the nozzle is formed as a groove, the effective heating area can be increased, and a jacket with high heat retention efficiency can be obtained.

Since the straight groove is only covered by the hard plate, by adjusting the thickness of the hard plate, the heated fluid passage formed by the straight groove can be brought closer to the die surface, and the nozzle can be moved closer to the die surface. It becomes possible to heat up to 100%.

[Brief explanation of drawings]

FIG. 1 is a partially cutaway front view showing an embodiment of a die for producing resin pellets according to the present invention, FIG. 2 is a cross-sectional view of the die shown in FIG. 1 taken along line II-II, and FIG. An enlarged cross-sectional view taken along the line ■-■ of the die shown in Fig. 1. Fig. 4 is a partially cutaway front view showing an example of a conventional die for producing resin pellets. It is a sectional view taken along the -v line. 20...Dice 21...Dice body 21a
...Surface 21b...Annular portion 22...Outer annular groove 22a...Upper arcuate groove 22b...Lower arcuate groove 23...Inner annular groove 26...Straight groove 26a... Bottom surface 27.28
．． 29... Partition body 30... Heating fluid introduction passage 31... Heating fluid discharge passage 33... Hard plate 34... Resin extrusion nozzle 34c... Taper part Fig. 4 1efgjG1-26G2υ7 (8 ) Figure 5 L

Claims (2)

[Claims] (1) An outer annular groove 22 and an inner annular groove 23 are provided on the surface 21a of the flat die body 21, and an annular portion 21b of the surface 21a is defined by the outer annular groove 22 and the inner annular groove 23. are provided with a large number of parallel straight grooves 26, 26, . . . in the vertical direction, and these outer annular groove 22, inner annular groove 23, and straight groove 2
6 is covered by an annular hard plate 33 which is diffusion-welded to the surface 21a of the die body 21, and a heating fluid introduction passage 30 communicating with the upper semicircular groove portion of the outer annular groove 22 and the lower semicircular groove portion. By providing a communicating heated fluid discharge passage 31, a jacket is formed through which the heated fluid flows, and a large number of holes passing through the die body 21 and the hard plate 33 are provided between each of the straight grooves 26, 26, . A die for manufacturing resin pellets, which is equipped with resin extrusion nozzles 34, 34, . (2) The bottom surface 26a of the straight groove 26 is connected to the nozzle 34.
The die for producing resin pellets according to claim 1, characterized in that the die has an inclined surface corresponding to the tapered portion 34c.