JP2911370B2 - Die for resin granulation and method for producing the same - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a resin granulating die provided at the tip of a screw type extruder when a material is kneaded and melted by a screw type extruder and granulated in water.

[0002]

2. Description of the Related Art FIG. 11 is a sectional view of a commonly used underwater granulator, FIG. 12 is a partial external view of a conventional die, and FIG.
FIG. 3 shows a sectional view of FIG. Reference numeral 1 denotes a screw-type extruder in which a screw 3 is rotatably inserted into an inner hole 2a of a cylinder 2. A substantially disk-shaped die 5 is connected to a tip of the cylinder 2 via a die holder 4. A cutter case 6 is connected to the die 5, and a cutter device 7 is installed in the cutter case 6 so as to face the die 5 and pass through the cutter case 6. The outer surface of the die 5 constitutes a part of the inner surface of the cutter case 6, and is provided with a discharge plane 5a protruding into the cutter case 6 in a circular band shape. Are provided so as to penetrate in the thickness direction. The resin passage nozzle 5b is formed by connecting holes having a circular cross section, whose inner surface side is thicker and whose outer surface side is thinner, by a middle vertical hole.

[0003] A heat medium flow path 5d is provided inside the die 5 adjacent to the resin passage nozzle 5b. An inner hole 4 a is formed in the die holder 4, and the inner hole 4 a communicates the inner hole 2 a of the cylinder 2 with the opening of the resin passage nozzle 5 b on the inner surface of the die 5. The cutter case 6
Has an inlet 6a for cooling water (warm water) below, and an outlet 6b for cooling water above. The cutter device 7
Has a plurality of cutter blades 7c held at the tip of a rotating shaft 7a protruding into a cutter case 6 via a cutter holder 7b.
are radially arranged in a plane perpendicular to the rotating shaft 7a so as to be slidable facing the a.

[0004] In the underwater granulator thus constructed, the resin material kneaded and melted by the screw type extruder 1 and extruded from the tip thereof passes from the inner surface of the die 5 through the die holder 4 to the resin passage nozzle 5b. Then, the resin is discharged into the cutter case 6 from the opening of the resin passage nozzle 5b of the discharge plane 5a in the form of a thin string having a circular cross section. During this time, the resin material in the resin passage nozzle 5b is replenished with the amount of heat radiated from the discharge plane 5a to the cooling water by heating the high-temperature heat medium flowing through the heat medium flow path 5d, and the fluidity is maintained. .
In the cutter case 6, cooling water is supplied from an inflow port 6a and discharged from an outflow port 6b, while the cutter blade 7c is
The rotary shaft 7a is driven to rotate in a state of contact with the discharge plane 5a.

[0005] From the resin passage nozzle 5b to the cutter case 6
The string-like resin material discharged into the inside is cooled and solidified by the cooling water, cut by the cutter blade 7c, granulated into pellets, dispersed in the cooling water and cooled, and cooled by the cooling water from the outlet 6b. It is discharged with. As a dice for resin granulation in such an underwater granulation apparatus, there is a conventional dice according to Japanese Patent Application No. 3-290016 of the present applicant.

In this type of die 5, at the time of granulation, the cutter blade 7c always slides at high speed on the discharge plane 5a, and the discharge plane 5a and the cutter blade 7c are worn. Although the cutter blade 7c is replaced when worn as a consumable part, the die 5 is an expensive main part and is not frequently replaced. Therefore, the discharge flat surface 5a is subjected to a special wear-resistant process, so that the die 5 is protected against wear. The life of parts has been improved. In the invention of the applicant described above, FIG.
As shown in FIG. 3, in the discharge-side surface layer of the die 5, that is, in the discharge plane 5 a,
The wear-resistant powder alloy is pressure-sintered by hot isostatic pressing (HIP) to form a hardened layer 5c.
c, a resin passage nozzle 5b is formed. H
The cured layer 5c formed by pressure sintering by the IP method is
An abrasion-resistant material which is easily formed at an arbitrary position at an arbitrary thickness and is firmly bonded to the base material of the die 5 by diffusion bonding.

[0007]

Problems to be Solved by the Invention Since the conventional resin granulating dies are configured as described above, there are the following problems. That is, the die 5 is heated to a high temperature in order to maintain the flow state of the resin material, but the outer surface of the die 5 forms a part of the inner surface of the cutter case 6, and the discharge plane 5a which is a part thereof is formed. Is always in contact with cooling water (hot water) having a temperature of 60 to 80 ° C. flowing in the cutter case 6. Therefore, the die 5 constantly radiates heat from the discharge plane 5a to the cooling water, and a continuous temperature gradient is generated from the discharge plane 5a in the thickness direction, and the temperature on the discharge plane 5a side decreases. On the other hand, the resin material is heated and kneaded in the screw type extruder 1 and discharged in a molten state at 200 to 300 ° C, but loses fluidity at 150 to 180 ° C and solidifies. The die 5 is heated around the resin passage nozzle 5b with a high-temperature heat medium, and replenishes the amount of heat radiated from the discharge plane 5a to the cooling water to maintain the temperature of the resin material at or above the freezing point.
A slight change in operating conditions can unexpectedly lower the temperature of the resin material and solidify it. When the resin material is solidified in the resin passage nozzle 5b, it is almost impossible to re-melt the extruder 1 and the underwater granulator while the operation is continued. It must be restarted after draining the cooling water and re-melting the solidified resin material. Various arrangements have been made for the arrangement of the heat medium flow path 5d so as to approach the resin passage nozzle 5b and the discharge plane 5a as much as possible. However, there is a limit, and a sufficient amount of heat may not be supplied.

The present invention has been made to solve the above problems, and in particular, provides a resin granulating die in which a resin material is prevented from solidifying in a resin passage nozzle, and a method of manufacturing the same. The purpose is to:

[0009]

A resin granulating die according to the present invention has a plate shape and is provided with a plurality of resin passage nozzles penetrating in the thickness direction thereof, and a powder layer is formed on a discharge-side surface layer of the resin passage nozzle. In a resin granulation die formed of a die having a hardened layer formed by pressure sintering the alloy by hot isostatic pressing, a space is provided on the bottom side of the hardened layer, and the space between the hardened layer and the space is provided. The configuration is such that a partition plate is provided between them.

In the method for manufacturing a resin granulating die according to the present invention, a concave portion is formed in the thickness direction from the discharge plane side on the discharge plane side where the resin passage nozzle penetrates in the thickness direction of the plate-like die. Providing a pressure equalizing hole communicating from the bottom surface of the concave portion to the side opposite to the discharge surface of the die, covering the bottom portion of the concave portion with a partition plate through a space, and filling the concave portion outside the partition plate with the powder alloy. Then, the powder alloy is pressure-sintered by a hot isostatic pressing method to form a hardened layer, and then the resin passing nozzle is formed by penetrating the die, the partition plate and the hardened layer.

[0011]

In the resin granulating die according to the present invention, the space formed at the bottom of the hardened layer formed on the discharge side surface layer acts as a heat insulating layer, and the low temperature on the discharge plane side is blocked by this space. The high temperature state around the resin passage nozzle from the inner surface side to the space is maintained. Therefore, the resin material discharged by flowing through the resin passage nozzle is maintained in a high-temperature molten state close to a space between the discharge planes, and does not solidify even when cooled during a short distance of the hardened layer thereafter. Fluidity is ensured and the liquid is easily discharged. The space communicates with the resin passage nozzle, and the resin material flowing through the resin passage nozzle flows in and fills in the initial stage, but the resin material has a significantly lower thermal conductivity than the metal material, and the resin material layer is formed. Acts as a heat insulating layer. In the method for granulating a resin granulating die according to the present invention, the bottom of the recess is covered with a partition plate via a space, and the powder alloy is filled on the outside thereof, whereby the powder alloy is supported by the partition plate. Thus, the pressure sintering by the hot isostatic pressing method is performed without any trouble, and a space can be easily formed on the bottom surface of the hardened layer.

[0012]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Preferred embodiments of a resin granulating die and a method for producing the same 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 to 7 show a resin granulating die according to the present invention. FIGS. 1 to 3 show radial partial cross-sections of a place where the present invention is carried out, and FIGS. 4 to 7 show the present invention. It is a figure which shows the partial outer surface of the place where it fell. FIGS. 1, 2, and 3 are FIGS. 4, 5, and 6, respectively.
FIG. 8 is a sectional view with respect to the external view of FIG. 7. 1 and 4 show an embodiment in which a common recess 5g is applied to a plurality of resin passage nozzles 5b in the radial direction, and FIGS. 2 and 5 show an embodiment in which a recess 5g is applied to each resin passage nozzle 5b. For example, FIGS. 2 and 6 show an embodiment in which a common recess is applied to a plurality of resin passage nozzles 5b on a full circle or a partial arc in one row in the circumferential direction, and FIGS. 3 and 7 show circles. An example is shown in which a common recess 5g is applied to a plurality of resin passage nozzles 5b on the entire circumference or a partial arc in all rows in the circumferential direction. 1 to 7, a die 5 has a substantially disk shape similarly to the conventional example, and a discharge plane 5a concentric with the disk shape and protruding in a trapezoidal shape in a radial cross section is formed on the outer surface. Are provided with a large number of resin passage nozzles 5b penetrating in the thickness direction of the die 5. The resin passage nozzle 5b is formed by connecting holes having a circular cross section, whose inner surface side is thicker and whose outer surface side is thinner, by a circular hole in the middle.

In this embodiment, a large number of resin passage nozzles 5b
Are provided at equal intervals in the circumferential direction and the radial direction of the discharge plane 5a. Each resin passage nozzle 5b
Is formed such that a portion of the narrow hole on the outer surface side on the discharge plane 5a side is connected to the bottom surface of the hardened layer 5c and the partition plate 5e press-sintered from the discharge plane 5a side by the hot isostatic pressing method (HIP method). A space 5f is formed in a portion formed by the partition plate 5e, and further, a space 5f is formed on the anti-cured layer 5c side, which is the inner surface side of the partition plate 5e. A heat medium flow path 5d is provided around the resin passage nozzle 5b.

In the resin granulating die having the above-described configuration, the screw is heated while the heat medium is supplied from an external heat medium device (not shown) to the heat medium passage 5d and the die 5 is heated. When the hot-kneaded resin material in the hot-melted state is extruded from the extruder 1, the resin material flows through the resin passage nozzle 5b from the inner surface of the die 5, and flows from the discharge plane 5a into the cutter case 6 with a thin string having a circular cross section. It is discharged in a shape.

At the start of operation, the inside of the cutter case 6 is filled with cooling water almost simultaneously with the discharge of the resin material from the discharge plane 5a, and the cutter blade 7c is brought into contact with the discharge plane 5a and slidably rotated. The thin string-shaped resin material discharged into the cutter case 6 is immediately cooled by cooling water and solidified, cut by the cutter blade 7c and granulated into pellets,
It is dispersed and cooled in the cooling water, and the outlet 6 together with the cooling water.
b to the outside of the cutter case 6. Thereafter, the resin material continuously flows through the resin passage nozzle 5b of the die 5, is discharged from the discharge plane 5a, and is granulated.

In the resin passage nozzle 5b, a part of the resin material flowing from the inner surface side of the die 5 is
flows into f. The resin material that has flowed into and filled the space 5f forms a poor heat conductor in the space 5f. For example, the thermal conductivity of cemented carbide, which is a material usually used as the hardened layer 5c of the die 5, and the thermal conductivity of TiC are 60, 18 to 20 respectively.
Although it is Kcal / MH ° C, the thermal conductivity of typical resin materials such as polyethylene or polypropylene is 4-5 Kcal.
/ MH ° C, and the thermal conductivity of the resin material is much lower than that of the material of the cured layer 5c. The die 5 is heated to a high temperature by heating with a heat medium and a high-temperature molten resin, and its outer surface is cooled by cooling water filling the inside of the cutter case 6,
Although the temperature decreases in the outer surface direction, the decrease in temperature is blocked by the resin material filling the space 5f. Accordingly, the die 5 forming the resin passage nozzle 5b maintains a sufficiently high temperature state from the inner surface to the space 5f, and the temperature is reduced by the influence of the cooling water only when the distance from the outer surface to the space 5f is a little. Become.

That is, the resin material flowing through the resin passage nozzle 5b maintains a high-temperature molten state having sufficient fluidity from the inner surface to the space 5f, and solidifies at a small flow distance from the space 5f to the outer surface. Shortly thereafter, the liquid is discharged from the discharge plane 5a. 8 to 10
1 shows a method (procedure) for manufacturing a resin granulating die according to the present invention, and typically shows the case shown in FIG. 1, but the cases of FIGS. 2 and 3 are the same as in FIG. 1. Applied.

In FIG. 8, a die 5 formed with a hole having a large circular cross section on the inner surface side of a resin passage nozzle 5b and a heat medium flow path 5d is provided on a discharge plane 5a in a two-step recess 5g in the plate thickness direction.
Is formed. In the two-step concave portion 5g, a step 5h is formed over the entire periphery of the boundary between the outer first step having a large flat area and the second step having a small flat area. The planar shape of the concave portion 5g is a fan shape or a substantially rectangular shape in the embodiment of FIG. 4, the circular shape in the embodiment of FIG. 5, and the circular shape along the circular band-shaped discharge plane 5a in the embodiments of FIGS. It becomes a groove of a shape or a partial arc. Each recess 5g is provided with at least one pressure equalizing hole 5k communicating from the bottom surface to the inner surface side of the die 5, so that the pressure equalizing hole 5k later becomes a part of the resin passage nozzle 5b. Are provided at the center of a hole having a large circular cross section on the inner surface side.

Next, in FIG. 9, the partition plate 5e is placed on the step 5h, and the space outside the partition plate 5e is filled with the powdered alloy. The partition plate 5e is in the form of a flat plate that covers the entire surface in conformity with the planar shape of the concave portion 5g. The concave portion 5g is divided by the partition plate 5e into a bottom space 5f and a portion filled with the outer powder alloy. In this state, the powder alloy is pressure-sintered by the HIP method to form a hardened layer 5c that forms the discharge plane 5a. That is, the hardened layer 5c is formed with the space 5f provided inside.
At this time, the space 5f is equalized with the outside by the equalizing hole 5k,
The partition plate 5e is pressed by the same pressure from both sides, so that HIP processing is performed without causing any trouble such as deformation. Thereafter, the remaining portion including the hardened layer 5c is drilled in accordance with the resin passage nozzle 5b formed first inside, and as shown in FIGS. 1 to 7, the die through which the resin passage nozzle 5b penetrates is formed. It becomes 5.

A recess 5g formed in the discharge plane 5a
Instead of the two-step recess 5g provided with the step 5h shown in FIG. 8, a recess 5g having a rectangular cross section without the step 5h is provided as shown in FIG.
An obstacle 5i having the same height as the depth f, for example, a wire or a piece member is arranged at the corner of the bottom surface of the concave portion 5g or at an appropriate intermediate position, and a partition plate 5e full of the planar shape of the concave portion 5g is placed thereon.
May be placed. In the die 5 manufactured as described above, the resin passage nozzle 5b penetrating from the inner surface side of the die 5 to the discharge surface 5a on the outer surface side is a space formed at a part closer to the thickness of the hardened layer 5c from the discharge plane 5a. 5f crosses and communicates.

[0021]

The resin granulating die and the method for producing the same according to the present invention are configured as described above, so that the following effects can be obtained. That is, since there is a space on the bottom side of the hardened layer, the resin material flowing through the resin passage nozzle is cooled only in a small portion (hardened layer) near the discharge plane, and is maintained at a sufficiently high temperature in most other portions. As a result, the resin material was discharged immediately after solidification, and the resin material did not solidify in the resin passage nozzle. Therefore, the operation of the extruder and the underwater granulation apparatus was not suddenly stopped, and a good continuous operation became possible. Furthermore, since the resin material is discharged and granulated at a substantially constant temperature, the physical quality is constant, and the discharge speed is constant, so that the shape quality is also constant. Further, a recess is formed in the thickness direction from the discharge plane of the die, an obstacle is provided at the bottom of the recess, and the outer surface covered with the partition plate is filled with the powder alloy through the obstacle, and HIP is performed.
By sintering under pressure by the method, it is possible to produce a die that is formed on the ejection side surface layer without the need for complicated and difficult techniques, with a hardened layer that is extremely strongly bonded while forming a space inside. became.

[Brief description of the drawings]

FIG. 1 is a partial radial sectional view (a sectional view taken along the line II of FIG. 4) of a die according to the present invention.

FIG. 2 is a partial radial sectional view of the die according to the present invention (a sectional view taken along line II-II in FIGS. 5 and 6).

FIG. 3 is a partial radial sectional view (III-III sectional view of FIG. 7) of a die according to the present invention.

FIG. 4 is a partial outer surface (partially sectional view) of a die according to the present invention.

FIG. 5 is a partial outer surface (partially sectional view) of a die according to the present invention.

FIG. 6 is a partial outer surface (partially sectional view) of a die according to the present invention.

FIG. 7 is a partial outer surface (partially sectional view) of a die according to the present invention.

FIG. 8 is a partial radial sectional view showing a method (procedure) for manufacturing a die according to the present invention.

FIG. 9 is a partial radial sectional view showing a method (procedure) for manufacturing a die according to the present invention.

FIG. 10 is a partial radial sectional view showing a method (procedure) for manufacturing a die according to the present invention.

FIG. 11 is a cross-sectional view showing a normal underwater granulation apparatus.

FIG. 12 is a partial external view of a conventional die.

FIG. 13 is a sectional view taken along line XIII-XIII of FIG.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Screw-type extruder 5 Die 5a Discharge plane 5b Resin passing nozzle 5c Hardened layer 5e Partition plate 5f Space 5g Depression 6 Cutter case 7 Cutter device 7c Cutter blade

──────────────────────────────────────────────────続 き Continued on the front page (72) Inventor Kenjiro Riki 1-6-1, Funakoshi Minami, Aki-ku, Hiroshima-shi, Hiroshima Japan Steel Works Co., Ltd. (72) Inventor Yoshitomo Tanaka 1-chome, Funakoshi-minami, Aki-ku, Hiroshima-shi, Hiroshima No. 6-1 Japan Steel Works Co., Ltd. (72) Inventor Toshio Matsuo 1-6-1, Funakoshi Minami, Aki-ku, Hiroshima City, Hiroshima Prefecture Japan Steel Works Co., Ltd. (72) Inventor Yasuhiko Ishida Funakoshi-minami, Hiroshima City, Hiroshima Prefecture 1-6-1, Japan Steel Works, Ltd. (56) References JP-A-5-245833 (JP, A) JP-A-62-262711 (JP, A) (58) Fields investigated (Int. Cl. ⁶⁾ , DB name) B29B 9/06 B29C 47/30

Claims (2)

(57) [Claims] A plurality of resin passage nozzles (5b) having a plate shape and penetrating in a thickness direction thereof are provided, and said resin passage nozzle
(5b) In the resin granulation die comprising a die (5) in which a powder alloy is sintered under pressure by hot isostatic pressing on the discharge side surface layer of the discharge side surface layer (5b), A space (5f) is provided on the bottom side of (5c), and a partition plate (5e) is provided between the hardened layer (5c) and the space (5f). Dies. 2. On a discharge plane (5a) side through which a resin passing nozzle (5b) penetrates in a plate thickness direction of a plate-shaped die (5), a concave portion (5g) is formed from the discharge plane (5a) side in a plate thickness direction. ), A pressure equalizing hole (5k) communicating from the bottom surface of the concave portion (5g) to the side opposite to the discharge plane (5a) of the die (5) is provided, and the bottom portion of the concave portion (5g) is formed into a space (5f). Cover with a partition plate (5e), fill the recess (5g) outside the partition plate (5e) with a powder alloy, press-sinter the powder alloy by hot isostatic pressing and cure Form a layer (5c), then the die (5), a partition (5e) and a hardened layer (5c)
And forming the resin passage nozzle (5b) through the resin die.