JP3032675B2 - Die for granulation - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a granulating die.
In particular, the present invention relates to a novel improvement for enabling low pressure loss and underwater start by uniform heating of a nozzle and obtaining good quality pellets.

[0002]

2. Description of the Related Art Generally, there are a large-capacity type for cutting resin in water and a small-capacity type for use in the air or in the form of a mist. Are often adopted. In this case, a heating method using a heat medium is adopted as a jacket structure to uniformly heat a large number of nozzles in a large-capacity processing of 2 T / H or more. When the method is used, the equipment cost increases, and thus a method using electrothermal heating is generally used. In the case of this electric heating, the first conventional example shown in FIG. 5 and the second conventional example shown in FIG. 6 and FIG.
A conventional example and a third conventional example shown in FIGS. 8 and 9 can be cited. That is, in the case of the first conventional example shown in FIG. 5, what is indicated by reference numeral 1 in the figure is a die holder provided at the tip of an extruder (not shown) and having a substantially cylindrical shape and having a molten resin flow path 2. A heating element 3 is provided on the outer periphery of the die holder 1, and the molten resin flow path 2 is tapered at a front end 1 a of the die holder 1.

At the front end 1a of the die holder 1, a substantially disk-shaped die 5 is detachably provided via a plurality of tightening bolts 4, and a heater 6 is provided on a peripheral surface of the die 5. ing. The die 5 is provided with a plurality of nozzles 7 arranged in a ring. In a cutter box 12 provided on the discharge surface 5a side of the die 5, a rotating shaft 9 driven to rotate by a motor 8 and a cutter driving device 8A projects vertically with respect to the discharge surface 5a of the die 5,
A cutter holder 10 is provided at the tip, and a plurality of cutter blades 11 radially provided in a direction perpendicular to the axis of the rotating shaft 9 are provided on a peripheral edge of the cutter holder 10 at a discharge surface of a die 5 which is a tip of each of the nozzles 7. 5a is provided so as to be substantially in contact therewith.

Accordingly, in the configuration shown in FIG. 5, the molten resin extruded from an extruder (not shown) is supplied to the die holder 1.
Is discharged from the nozzle 7 of the die 5 into the water of the cutter box 12 filled with the cooling water 12A through the molten resin flow path 2 and is cut into the pellets 12B by the cutter blades 11 one after another.

Next, the structure shown in FIGS. 6 and 7 shows another conventional example of the heater 6 shown in FIG. 5, in which a plurality of rod-shaped heaters 6A are radiated from the outer periphery of the die 5 in the radial direction. The dies 5 are inserted and arranged such that their tips reach the outer peripheral portions of a plurality of nozzles 7 arranged in a ring, and the dies 5 are connected to the die holder 1 through a plurality of tightening bolts 4 by utilizing a space between the heaters 6. The configuration is fixed to.

Next, the configuration shown in FIGS. 8 and 9 shows another conventional example using a heater 6A having a rod shape shown in FIGS. 6 and 7, and a plurality of nozzles 7 are connected to each other. A configuration has been proposed in which the nozzles 7 are arranged radially along both sides of the rod-shaped heater 6A to improve the temperature unevenness of each nozzle 7.

[0007]

Since the conventional granulating dies have the above-described structure, there are the following problems. That is, since the die surface is always exposed to the cooling water, the temperature near the nozzle is strongly affected by the temperature of the cooling water, and the temperature of the nozzle of the die is large, as shown in FIG. As the temperature in the vicinity decreases, the resin temperature decreases, the viscosity increases,
Partial clogging may occur. Therefore, such a heating method has a disadvantage that it can be used only for a limited resin material having a small change in viscosity. In addition, in the conventional example shown in FIGS. 6 and 7, a plurality of rod-shaped heaters are radially arranged as a method of heating the vicinity of the nozzle. However, since the distance between the heater and each nozzle is different, the vicinity of the heater can be heated even at a high temperature. The temperature became lower as the distance increased, and the clogging phenomenon occurred in the lower temperature part. Further, as shown in FIGS. 8 and 9, when nozzles are arranged on the left and right sides of the rod-shaped heater, each nozzle is in the same heating state, but the minimum peripheral speed of the cutter blade is usually required to be 10 m / sec or more. Therefore, the nozzles are arranged in the outer diameter direction with reference to the peripheral speed of the cutter blade at the position of the nozzle arranged inside, thereby increasing the diameter of the die and the driving power of the cutter as compared with the conventional example described above. Was growing up. Further, as the diameter of the die is increased, the inner diameter D of the pressure receiving portion shown in FIG. 5 is increased, and the pressure receiving area with respect to the molten resin pressure of the die is increased. Therefore, it is necessary to increase the thickness of the die itself in terms of strength. . As a result, there are drawbacks such as a significant increase in cost and an increase in pressure loss. Further, in the dies in which the surface of the dies is in direct contact with the cooling water as in the above-described conventional examples, there is a serious problem at the time of starting operation. In other words, even though the dies before passing water through the cutter box are heated and maintained at a substantially uniform temperature as a whole, the surface of the dies is rapidly cooled at the same time as passing water, and the molten resin in the nozzle is cooled and solidified. Therefore, the molten resin must be discharged instantaneously from the nozzle simultaneously with the passage of the cooling water, and if the molten resin is discharged earlier before the passage of the water, the resin adheres to the cutter blade and cannot be cut. For this reason, delicate timing is required for water flow and discharge of the resin from the nozzle, and a delicate feeling of an operator is required in an actual operation, and the operation is extremely difficult for non-experts.

The present invention has been made in order to solve the above-mentioned problems, and in particular, uniformly heats a plurality of nozzles, enables low pressure loss and easy start of operation, and obtains good-quality pellets. An object of the present invention is to provide a granulating die as described above.

[0009]

SUMMARY OF THE INVENTION A granulating die according to the present invention is provided on the downstream side of a substantially cylindrical die holder provided at the tip of an extruder and having a linear molten resin flow path therein and flanges at both ends. A plurality of nozzles, which are held by the flange portion and pass through the molten resin flow path in a thickness direction and are formed in a substantially disc shape and communicate with the molten resin flow path, are provided. In a granulating die configured to discharge resin from the plurality of nozzles, a plurality of radially formed radially in communication with the molten resin flow path on an end surface of a downstream flange portion of the molten resin flow path. A die is formed with a flow path and a circular flow path or an arcuate flow path formed in a circular or arc shape by communicating with a tip of each of the radial flow paths. To each of the circular channels in the Has a deep groove-shaped circular groove flow path or an arc-shaped groove flow path formed by extending the arc-shaped flow path, and each of the nozzles has a groove bottom of the circular groove flow path or the arc-shaped groove flow path. And a plurality of nozzles are provided to penetrate the discharge surface, and each of the circular flow paths or the arc-shaped flow paths, the respective circular groove flow paths or the arc-shaped groove flow paths, and the center of each of the plurality of nozzles. A rod-shaped heater is inserted and arranged in a direction perpendicular to the surface and from the back of the downstream flange portion.

The granulating die according to the present invention is held at the downstream flange of a substantially cylindrical die holder provided at the tip of an extruder and having a linear molten resin flow path inside and flanges at both ends. A plurality of nozzles having a substantially disc shape and communicating with the molten resin flow path are provided so as to penetrate in the thickness direction, and the plurality of molten resins extruded from the extruder via the molten resin flow path are provided. In the granulating die configured to be discharged from the nozzle, the die holder having the molten resin flow path is connected to the molten resin flow path at a joint surface portion with the end face of the downstream flange portion of the die holder. A plurality of radial flow paths formed radially, and a circular groove flow or an arc-shaped groove flow formed in a circular or arc shape in communication with the tip of each of the radial flow paths and forming a deep groove in the discharge surface direction. And a road A plurality of nozzles are respectively provided through the discharge surface from the groove bottom of each of the circular groove flow paths or the arc groove flow paths, and each of the circular groove flow paths or the arc groove flow paths and the plurality of nozzles are provided. A bar-shaped heater is inserted and arranged in the center of the vertical direction with respect to the discharge surface and from the back of the downstream flange.

[0011]

In the granulating die according to the present invention, the molten resin extruded from the extruder or the like through the molten resin flow path of the die holder is joined at the downstream end of the molten resin flow path to the joint surface between the die holder and the granulating die. A plurality of radial flow paths provided in communication with each other further branch and flow into a circular flow path or an arc-shaped flow path or a circular groove flow path or an arc-shaped groove flow path communicating with the distal end thereof, and flow into each circular groove. The fluid flows into a plurality of nozzles of each of the groove channels provided to penetrate the discharge surface in the granulating die in communication with the channel or the arc-shaped groove channel, and forms a thin string (strand) from the nozzle tip. Discharged. During this time, the rod-shaped heater is equidistant over a long section with respect to each circular flow path or arc-shaped flow path or circular groove flow path or arc-shaped groove flow path and a plurality of nozzles arranged in a circular or arc shape. It is arranged parallel to the position, and its tip is inserted close to the discharge surface of the granulating die, so that the molten resin flowing inside each flow path and nozzle is evenly distributed over a long section and up to the nozzle tip. Heated enough. Further, each circular groove flow path or arc-shaped groove flow path is formed deep in the thickness direction of the granulating die,
The flow path resistance is reduced by reducing the length of the nozzle having a small flow path cross-sectional area, and the flow resistance of the molten resin flowing inside them is significantly reduced due to the synergistic effect with the sufficient heating described above. That is, the extrusion pressure of the extruder decreases.

[0012]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Preferred embodiments of a granulating die according to the present invention will be described below in detail with reference to the drawings. The same or equivalent parts as those in the conventional example will be described with the same reference numerals. 1 is a cross-sectional view showing the entire configuration of a granulating die according to the present invention, FIG. 2 is a cross-sectional view taken along the line AA of FIG. 1, FIG. 3 is a cross-sectional view showing another embodiment of FIG. FIG. 3 is a cross-sectional view illustrating the entire configuration of the example. In the figure, reference numeral 1 denotes a die holder having a substantially cylindrical shape, having flange portions 1a formed at both ends (upstream and downstream sides) and having a molten resin flow path 2 at its axial center. Is a substantially disk-shaped die 5
Are held by a plurality of tightening bolts 4. A heating element 3 is provided on the outer periphery of the cylindrical portion of the die holder 1,
As shown in FIG. 2, the molten resin flow path 2 has a radial flow path 20 formed of a plurality of grooves or holes formed in the radial direction at the front end face of the downstream flange 1a. A circular flow path 21 composed of a circular groove or hole is formed at the position of the tip of the flow path 20. The adjacent circular flow path 21 or a die 5 communicating therewith.
At each intermediate position of a circular groove flow path 21a described below formed at the center of the nozzle group 7A formed at the bottom of the groove, a tightening bolt 4 can be arranged, and the die 5 is fixed to the die holder 1. Is held.

As shown in FIG. 1, each of the circular flow paths 21 is formed in a deep groove shape over the die holder 1 and the die 5, and the die holder 1 of each of the circular flow paths 21 is formed.
, That is, the front end face of the downstream flange 1a of the die holder 1 is formed such that the cross-sectional area of the flow path gradually decreases in the direction of travel of the flow path. That is, since the flow rate of the molten resin is sequentially branched and discharged to a plurality of nozzles 7 described later communicating with the circular flow path 21, the flow rate decreases in the flow direction of the flow path. The circular flow path 21 is formed so as to gradually reduce the flow path cross-sectional area in the traveling direction. Each of the circular flow paths 21 is extended in the direction of the discharge surface 5a to form a deep groove-shaped circular groove flow path 21a at a joining surface portion of the die 5 on the die holder 1 side. The groove of the circular groove flow path 21a is formed. A plurality of nozzles 7 penetrating from the bottom to the discharge surface 5a
Are formed, and a plurality of nozzles 7 are provided for each circular groove flow path 21a.
This constitutes the nozzle group 7A. Each nozzle group 7A
Are usually arranged at regular intervals.

Since the circular groove flow path 21a is a circular groove having a small radius of curvature, the circular plane area including the circular groove is small, and the pressure of the molten resin acting on this circular plane, that is, the nozzle group 7A arranged in a circular shape. Since the shear force acting on the wall surface between the adjacent nozzles 7 is small, the length of the wall surface, that is, the length of the nozzle 7 can be reduced. Therefore, the circular groove flow path 2 can reach the allowable range of the shear strength of the wall surface.
The circular groove 1a can be formed deeply, the flow resistance of the molten resin decreases, and the pressure required for discharge decreases.
Further, by making the circular groove flow channel 21a shallow, the thickness of the die 5 can be reduced.

Each of the circular flow paths 21 and the circular groove flow paths 21a
In the central part of each, a bar-shaped elongate bar-shaped heater 6A is provided. The rod-shaped heater 6A is mounted on the die holder 1 from the rear side of the downstream flange 1a of the die holder 1.
And the die 5 is inserted and held in a guide hole 23 formed in the thickness direction of the die 5 to near the discharge surface 5a. That is, the rod-shaped heater 6A is
a and the nozzles 7 of the nozzle group 7A.

At the outer end of the die 5, a thermocouple 24 for detecting the temperature near the tip of the nozzle 7 is provided. A rotary shaft 9 driven by a motor (not shown) protrudes vertically from the discharge surface 5a of the die 5 into a cutter box 12 disposed on the discharge surface 5a side of the die 5 and has a tip thereof. Is provided with a cutter holder 10. A plurality of cutter blades 1 provided radially on the periphery of the cutter holder 10 in a direction perpendicular to the axis of the rotating shaft 9.
1 is a discharge surface 5a of a die 5 which is a tip of each nozzle 7
It is arranged in a state almost in contact with.

Next, the operation will be described. 1 and 2, the molten resin extruded from a booster (not shown) such as an extruder or a gear pump is supplied to a molten resin flow path 2, a radial flow path 20, a circular flow path 21, and a circular groove flow. The water is discharged from the nozzle 7 into the cooling water 12A of the cutter box 12 via the path 21a, cut by the cutter blades 11, and formed into pellets 12B one after another.

The molten resin flowing through the circular flow path 21 is:
Since the flow is gradually branched off and discharged to the nozzle 7 through the circular groove flow path 21a, the flow amount gradually decreases. However, the flow path cross-sectional area is formed so as to gradually decrease in the traveling direction in accordance with the decrease amount. Therefore, the fluid always flows at a constant flow rate to the tip of the circular flow path 21, and the same discharge pressure is generated in all the nozzles 7 of the nozzle group 7A. Therefore, in all the nozzles 7 of the nozzle group 7A, the molten resin is discharged under the same discharge condition.

Further, in the center of each nozzle group 7A, a rod-shaped heater 6A is buried vertically from the die holder 1 to the discharge surface 5a of the die 5 to near the discharge surface 5a. Since the rod-shaped heater 6A is arranged at an equidistant position along the inner peripheral surface of each circular groove flow path 21a and the nozzle group 7A, the rod heater 6A flows through each circular groove flow path 21a and each nozzle 7. The molten resin to be heated is efficiently heated to a uniform and uniform temperature, and is sufficiently heated to the tip of each nozzle 7.

Since the rod-shaped heater 6A is inserted close to the discharge surface 5a of the die 5, the discharge surface 5
The molten material near "a" is sufficiently heated by supplementing the amount of heat radiated from the discharge surface 5a to the cooling water 12A, and is constantly maintained in a dischargeable state. That is, the molten resin is uniformly heated in the plurality of nozzles 7, and is sufficiently heated to a dischargeable state even with respect to the cooling effect by the cooling water 12A.

As described above, in the flow path of the molten resin in the die 5, the length of the nozzle 7 having a small cross-sectional area of the flow path is reduced, the flow path resistance is reduced, and the molten resin is sufficiently heated by the rod-shaped heater 6A. Is performed, the flow resistance of the molten resin is greatly reduced, and the discharge surface 5a is formed at a low discharge pressure.
Is discharged from.

Further, the shearing force acting on the wall surface between the nozzles 7 of the nozzle group 7A formed at the tip of the circular groove channel formed by the circular groove having a small radius of curvature is proportional to the low discharge pressure of the molten resin. And the length of the nozzle 7 can be further reduced. Therefore, a thin disk-shaped die 5 having a low pressure resistance can be obtained. Further, the tightening bolt 4 for the die 5 and the die holder 1 is connected to the circular groove flow path 2.
By providing it in the middle part of 1, the diameter of the disk-shaped die 5 can be reduced.

Further, since the molten resin is sufficiently heated also at the tip of the nozzle 7 of the die 5, the molten resin can be easily discharged even when the discharge surface 5a of the die 5 is cooled by the cooling water. it can.

In the conventional example, the heater 6 is disposed on the outer peripheral surface of the die 5 or the bar-shaped heater 6A is arranged radially inward from the outer peripheral surface.
The wiring and accessories of A are provided on the outer peripheral portion of the die 5 and further increase the outer peripheral diameter. However, according to the present invention, the rod-shaped heater 6A is perpendicular to the surface of the disk-shaped die 5 and its Since it is configured to be arranged inside, it is possible to arrange and configure the wiring and accessory parts within the outer diameter of the die 5.

In the structure of another embodiment shown in FIG.
The circular flow path 21 and the circular groove flow path 21a are a semicircular arcuate flow path 21A and an arcuate groove flow path 21Aa, and are located at the center positions of the arcuate flow path 21A and the arcuate groove flow path 21Aa. The bar-shaped heater 6A is provided. This embodiment can obtain a small-capacity processing configuration with respect to the large-capacity processing configuration shown in FIG. The arc-shaped channel 21A and the arc-shaped groove channel 21Aa are not limited to a semicircle.
An arc shape having an arbitrary central angle can be set according to the processing capacity.

Further, in the configuration of another embodiment shown in FIG. 4, grooves forming the radial flow path 20 and the circular flow path 21 or the arc-shaped flow path 21A are formed on the die 5 side. In such a configuration, the same operation and effect as those of the above-described configuration can be obtained.

[0027]

Since the granulating die according to the present invention is constituted as described above, the following effects can be obtained. That is, (1) a rod-shaped heater arranged at the center of each circular flow path or arc-shaped flow path or a circular groove flow path or an arc-shaped groove flow path and a nozzle group near the die surface along the nozzle group. The molten resin flowing in the flow path is uniformly and efficiently heated up to the nozzle tip to the nozzle tip. Therefore, even when the discharge surface of the die is cooled by the cooling water, the die can be heated to a dischargeable state, and granulation can be easily started without clogging. (2) The length of the nozzle portion having a small channel cross-sectional area is short, the molten resin is sufficiently heated, the flow resistance is reduced, and the radius of curvature of each circular channel or arc-shaped channel is small, so that the groove is formed. The required pressure-resistant strength is reduced by reducing the shearing force due to the discharge pressure acting between the adjacent nozzles of the nozzle group arranged in a circular shape at the bottom, and the outer diameter is reduced by configuring the nozzle group in a circular shape. In addition, it is possible to make the die thinner and smaller in diameter, that is, to make it smaller and lighter, and to arrange and arrange wiring and accessories within the outer diameter of the die by arranging the bar-shaped heater vertically on the discharge surface of the die. Becomes possible.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view showing an entire configuration of a granulating die according to the present invention.

FIG. 2 is a sectional view taken along line II-II of FIG.

FIG. 3 is a sectional view showing another embodiment of FIG. 2;

FIG. 4 is a cross-sectional view showing the overall configuration of another embodiment.

FIG. 5 is a sectional view showing a conventional granulating die.

FIG. 6 is a configuration diagram showing another conventional granulating die.

FIG. 7 is a cross-sectional view of FIG. 6 as viewed from a side.

FIG. 8 is a configuration diagram showing another conventional granulating die.

FIG. 9 is a sectional view of FIG. 8 as viewed from the side.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Die holder 2 Molten resin flow path 4 Tightening bolt 5 Die 5a Discharge surface 6A Rod heater 7 Nozzle 20 Radial flow path 21 Circular flow path 21A Arc-shaped flow path

──────────────────────────────────────────────────続 き Continuation of the front page (72) Inventor Minoru Yoshida 1-6-1, Funakoshi Minami, Aki-ku, Hiroshima-shi, Hiroshima Japan Steel Works Co., Ltd. (56) References JP-A-4-189509 (JP, A) 1986-81913 (JP, U) (58) Field surveyed (Int. Cl. ⁷ , DB name) B29B 9/00-9/16

Claims (2)

(57) [Claims] An extruder is provided at a distal end of an extruder and held by a downstream flange portion (1a) of a substantially cylindrical die holder (1) having a linear molten resin flow path (2) therein and flange portions at both ends. And
A plurality of nozzles (7) having a substantially disc shape and communicating with the molten resin flow path (2) are provided so as to penetrate in the thickness direction, and are extruded from the extruder through the molten resin flow path (2). In the granulating die configured to discharge the molten resin to be discharged from the plurality of nozzles (7), the molten resin flow is provided on the end face of the downstream flange portion (1a) of the molten resin flow path (2). A plurality of radial channels (20) radially formed in communication with the path (2); and a circular channel formed in a circular or arc shape in communication with a tip of each of the radial channels (20). (2
1) or die holder (1) formed with an arc-shaped flow path (21A)
In contrast, a deep groove-shaped circular groove formed by extending each of the circular flow paths (21) or the arc-shaped flow paths (21A) from the bonding surface with the die holder (1) toward the discharge surface (5a). A flow path (21a) or an arc-shaped groove flow path, and each of the nozzles (7) penetrates from the groove bottom of the circular groove flow path (21a) or the arc-shaped groove flow path to the discharge surface (5a). A plurality of each, the circular flow path (21) or the arcuate flow path (21A), the circular groove flow path (21a) or the arcuate groove flow path and the plurality of nozzles (7) At the center of the discharge surface
(5a) perpendicular to the and the downstream flange portion (1a)
A granulating die comprising a configuration in which a rod-shaped heater (6A) is inserted and arranged from the back surface of the granule. 2. A substantially cylindrical die holder (1) provided at a tip of an extruder and having a linear molten resin flow path (2) therein and flanges at both ends thereof is held by a downstream flange (1a). And
A plurality of nozzles (7) having a substantially disc shape and communicating with the molten resin flow path (2) are provided so as to penetrate in the thickness direction, and are extruded from the extruder through the molten resin flow path (2). In the granulation die configured to discharge the molten resin to be discharged from the plurality of nozzles (7), the die holder (1) having the molten resin flow path (2), the downstream of the die holder (1) A plurality of radial flow paths (20) radially formed in communication with the molten resin flow path (2) at the joint surface portion with the end face of the side flange portion (1a), and the respective radial flow paths
A circular groove or an arc groove formed in a circular or arc shape in communication with the tip of (20) and forming a deep groove in the direction of the discharge surface (5a); (7) is the discharge surface (5) from the groove bottom of each circular groove flow path (21a) or the circular groove flow path.
a) are provided in a plurality, respectively, and the respective circular groove flow paths (21a) or arcuate groove flow paths and each of the plurality of nozzles are provided.
A bar-shaped heater (6A) is provided at the center of (7) in a direction perpendicular to the discharge surface (5a) and from the back of the downstream flange (1a).
Characterized by having a configuration in which is inserted and arranged.