Pellet manufacturing apparatus

Abstract

Provided is a pellet manufacturing apparatus that is compact and easy to operate, and enables small-lot production including experiments and prototypes using a variety of resin materials. 【Solution means】A pellet manufacturing apparatus 1 includes an extrusion mechanism that melts a resin material M and extrudes the resin material M from an extrusion port 22 in a direction DG along gravity to form a strand S, a first forced cooling mechanism 40 and a second forced cooling mechanism 50 that forcibly cool the strand S moving along the direction DG along gravity from both sides with airflows, a feeding mechanism 60 that feeds the strand S, a cutting mechanism 70 that cuts the strand S, and a housing 80. The pellet manufacturing apparatus 1 is configured such that the strand S moves non-contact from the extrusion port 22 to the feeding mechanism 60, and is configured such that the strand S can be appropriately cooled and cured according to the properties of the resin material M by a forced cooling area C1 and natural cooling areas C2a, C2b.

Description

Technical Field

[0001] The present invention relates to a pellet manufacturing apparatus.

Background Art

[0002] Currently, a pellet manufacturing apparatus (pelletizer) for pelletizing resin materials is widely known (see, for example, Patent Documents 1 to 3). The pellet manufacturing apparatus is used for adjusting the components of the resin material by adding various additives (for example, colorants) in order to carry out the processes of melting and kneading the resin material for pellet production, and for pelletizing waste resin products to make them easier to recycle.

[0003] FIG. 9 is a diagram showing a conventional pellet manufacturing apparatus 900 for explanation. FIG. 10 is a diagram showing a conventional pellet manufacturing apparatus 901 for explanation. As a pellet manufacturing apparatus, those having an extrusion mechanism for melting and extruding a resin material, a cutting mechanism for cutting the extruded resin material, and a cooling mechanism for cooling the extruded resin material or pellets before or after cutting are common.

[0004] For example, a conventional pellet manufacturing apparatus 900 (see Patent Document 1) is a so-called strand type pellet manufacturing apparatus including an extrusion mechanism 910 for extruding a resin material as a rod-shaped strand S, a cooling water tank 920 as a cooling mechanism, a cutting mechanism 930, and a conveying mechanism 940 (rollers, etc.) for conveying the strand S (see FIG. 9). Although not shown, as a strand type pellet manufacturing apparatus, there are those having a blower and a water sprinkler as a cooling mechanism, cooling while conveying the strand by a conveying mechanism (belt conveyor, etc.), and those having a blower as a cooling mechanism and the strand moving on the surface of means (wire mesh, etc.) for restricting the oscillation of the strand are also known (see Patent Documents 2 and 3).

[0005] In addition, a conventional pellet manufacturing apparatus 901 (see Patent Document 4) includes an extrusion mechanism 910a, a cutting mechanism 930a disposed near the subsequent stage of the extrusion mechanism 910a, a water-mixed air blowing nozzle 922 which is a cooling mechanism, and a blower 924, and is a so-called hot cut type pellet manufacturing apparatus that forms the extruded resin material into pellets P before solidification (see FIG. 10).

[0006] According to the conventional pellet manufacturing apparatuses 900 and 901, it is possible to pelletize a resin material.

Prior Art Documents

Patent Documents

[0007]

Patent Document 1

Patent Document 2

Patent Document 3

Patent Document 4

Summary of the Invention

Problems to be Solved by the Invention

[0008] By the way, most of the conventional pellet manufacturing apparatuses are large (the size of a set of apparatuses is several meters to over 10 meters), and there are almost no small pellet manufacturing apparatuses, particularly tabletop-sized pellet manufacturing apparatuses that can be installed in a space of about one meter square and are easy to transport and move.

[0009] The reasons therefor include that large pellet manufacturing apparatuses tend to have higher simple manufacturing efficiency (processing speed per unit time), but it can also be said that the configuration of conventional pellet manufacturing apparatuses is not suitable for miniaturization.

[0010] For example, in a strand-type pellet manufacturing apparatus such as a conventional pellet manufacturing apparatus 900, since the strand is passed through a cooling mechanism such as a cooling water tank 920 and sent to a cutting mechanism 930, a large-scale conveying mechanism (rollers, belt conveyors, etc.) is required. In addition, each component is not integrated, which has accelerated the enlargement of the entire apparatus.

[0011] Also, in a hot cut-type pellet manufacturing apparatus such as a conventional pellet manufacturing apparatus 901, in order to cut the semi-molten resin without drawing it, it is necessary to rotate the cutting tool in the cutting mechanism at high speed, and the clearance between the cutting tool and the extrusion port (extrusion die) needs to be precision-controlled in units of several micrometers. To achieve this precision, the rigidity of the main body is required, so it is difficult to miniaturize the hot cut-type pellet manufacturing apparatus.

[0012] Also, in a hot cut-type pellet manufacturing apparatus, the resin immediately after cutting is in a semi-molten state and easily adheres to the wall surface and other resins, so it is necessary to cool it immediately. For this reason, in a hot cut-type pellet manufacturing apparatus, cooling in a shorter time is required compared to the strand type, and the cooling mechanism becomes complicated and enlarged. From this perspective as well, it is difficult to miniaturize the hot cut-type pellet manufacturing apparatus.

[0013] Due to technological advancements, resin injection molding apparatuses that can be owned and operated at the individual level are on the market, and the demand for pellet manufacturing apparatuses capable of adjusting resin materials at the individual level is increasing. In addition, as described above, since the minimum lot size of large-scale pellet manufacturing apparatuses inevitably increases due to their structure, while they are suitable for mass production, they are not suitable for small lot production and the examination of resin material conditions (experiments, prototypes, etc.). This is due to the long distance between the extrusion mechanism and the cutting mechanism in the strand-type pellet manufacturing apparatus, and the fact that a certain extrusion speed or more is required in the hot cut-type pellet manufacturing apparatus due to the rotational speed of the cutting tool.

[0014] Therefore, in the technical field of resins, there is a demand for a pellet manufacturing apparatus that is compact and easy to operate, and can perform small-lot production including experiments, prototypes, etc. using a variety of resin materials.

[0015] The present invention has been made in view of the above problems, and an object thereof is to provide a pellet manufacturing apparatus that is compact and easy to operate, and can perform small-lot production including experiments, prototypes, etc. using a variety of resin materials.

Means for Solving the Problems

[0016] [1] The pellet manufacturing apparatus of the present invention includes an extrusion mechanism that melts a resin material and extrudes the resin material from an extrusion port in a direction along gravity to form a continuous rod-shaped strand, a first forced cooling mechanism that forcibly cools the strand moving in the direction along gravity with an air flow, a second forced cooling mechanism that is disposed on the side opposite to the first forced cooling mechanism with respect to the path along which the strand moves, and forcibly cools the strand with an air flow together with the first forced cooling mechanism, a feeding mechanism that feeds the strand, a cutting mechanism that cuts the strand fed from the feeding mechanism, and a housing in which the extrusion mechanism, the first forced cooling mechanism, the second forced cooling mechanism, the feeding mechanism, and the cutting mechanism are disposed. The pellet manufacturing apparatus is configured such that the strand moves non-contact from the extrusion port of the extrusion mechanism to the feeding mechanism, and the strand is cooled and cured by a forced cooling area where the air flow from the first forced cooling mechanism and the second forced cooling mechanism directly hits the strand, and a natural cooling area where the air flow from the first forced cooling mechanism and the second forced cooling mechanism does not directly hit the strand.

[0017] [2] In the pellet manufacturing apparatus according to one aspect of the present invention, it is preferable that the extrusion mechanism includes a screw for kneading and extruding the resin material, a screw motor for rotating the screw, and a driving force transmission gear mechanism for transmitting the driving force by the screw motor to the screw.

[0018] [3] In the pellet manufacturing apparatus according to one embodiment of the present invention, it preferably further includes a feeding mechanism for feeding the resin material into the extrusion mechanism, and the feeding mechanism includes a hopper for introducing the resin material into the extrusion mechanism and a hopper motor for rotating the hopper.

[0019] [4] In the pellet manufacturing apparatus according to one embodiment of the present invention, the extrusion mechanism preferably includes a first temperature adjustment mechanism for adjusting the temperature on the side where the resin material is introduced and a second temperature adjustment mechanism for adjusting the temperature on the side where the resin material is melted.

[0020] [5] In the pellet manufacturing apparatus according to one embodiment of the present invention, the feeding mechanism includes a first feeding roller, a second feeding roller for sandwiching the strand between the first feeding roller, and a feeding roller motor for rotating at least one of the first feeding roller and the second feeding roller, and at least one of the first feeding roller and the second feeding roller is preferably configured to be movable.

[0021] [6] In the pellet manufacturing apparatus according to one embodiment of the present invention, as the natural cooling area, there are preferably a first natural cooling area existing on the die side rather than the first forced cooling mechanism and the second forced cooling mechanism, and a second natural cooling area existing on the feeding mechanism side rather than the first forced cooling mechanism and the second forced cooling mechanism.

[0022] [7] In the pellet manufacturing apparatus according to one embodiment of the present invention, when the length of the forced cooling area on the moving path of the strand is L1 and the length of the natural cooling area on the moving path of the strand is L2, the relationship of "L1≤L2" preferably holds.

[0023] [8] In the pellet manufacturing apparatus according to one embodiment of the present invention, it is preferable that at least one of the direction of the airflow and the discharge position of the airflow can be changed in the first forced cooling mechanism and the second forced cooling mechanism.

[0024] [9] In the pellet manufacturing apparatus according to one embodiment of the present invention, the extrusion mechanism further includes a hollow member having an internal space for melting and kneading the resin material, and a nozzle disposed at the tip of the hollow member and having an extrusion port formed at an end opposite to the hollow member side. The portion that actually generates the airflow in the first forced cooling mechanism and the second forced cooling mechanism is disposed outside the housing, and it is preferable that the hollow member side of the nozzle is disposed inside the housing and the extrusion port side is exposed outside the housing.

[0025]

[10] In the pellet manufacturing apparatus according to one embodiment of the present invention, it is preferable to further include a control mechanism for controlling at least two or more of the extrusion mechanism, the first forced cooling mechanism, the second forced cooling mechanism, the feeding mechanism, and the cutting mechanism.

Effects of the Invention

[0026] The pellet manufacturing apparatus of the present invention includes an extrusion mechanism that melts a resin material and extrudes the resin material from an extrusion port in a direction along gravity to form a continuous rod-shaped strand, a first forced cooling mechanism that forcibly cools the strand moving in the direction along gravity with an air current, a second forced cooling mechanism that is disposed on the side opposite to the first forced cooling mechanism with respect to the path along which the strand moves and forcibly cools the strand with an air current together with the first forced cooling mechanism, a feeding mechanism that feeds the strand, a cutting mechanism that cuts the strand fed from the feeding mechanism, and a housing in which the extrusion mechanism, the first forced cooling mechanism, the second forced cooling mechanism, the feeding mechanism, and the cutting mechanism are disposed. Further, the pellet manufacturing apparatus of the present invention is configured such that the strand moves non-contact from the extrusion port of the extrusion mechanism to the feeding mechanism, and the strand is cooled and cured by a forced cooling area where the air currents from the first forced cooling mechanism and the second forced cooling mechanism directly hit the strand and a natural cooling area where the air currents from the first forced cooling mechanism and the second forced cooling mechanism do not directly hit the strand.

[0027] Therefore, according to the pellet manufacturing apparatus of the present invention, the strand can be moved by gravity and the feeding mechanism, and the strand moving non-contact can be rapidly and stably cooled in the forced cooling area and the natural cooling area, so that the mechanisms for moving the strand and the cooling mechanism can be made remarkably compact.

[0028] In addition, in an apparatus that cools the strand in a state where the strand is in contact with a conveying mechanism (such as a belt conveyor) or a wire mesh as in a conventional pellet manufacturing apparatus (particularly the pellet manufacturing apparatuses described in Patent Documents 2 and 3), there is a problem that the cooling condition is biased between the contact surface side and the non-contact surface side of the conveying mechanism, the wire mesh, etc. and the strand, and the quality of the strand deteriorates. On the other hand, according to the pellet manufacturing apparatus of the present invention, since the strand moving in a non-contact state is cooled, it is possible to improve the quality of the strand by uniformizing the cooling, and thus improve the quality of the pellet.

[0029] Further, according to the pellet manufacturing apparatus of the present invention, since the airflows are generated from both sides of the strand by the first forced cooling mechanism and the second forced cooling mechanism, it is possible to stabilize the movement path of the strand even without the presence of a guide for conveyance or the like.

[0030] Further, according to the pellet manufacturing apparatus of the present invention, since each component is attached to one housing, the installation, movement, and operation of the apparatus can be facilitated.

[0031] Further, the pellet manufacturing apparatus of the present invention is a strand type pellet apparatus, and since the cooled and hardened strand is cut into pellets, the clearances and the body rigidity as high as those of a hot cut type pellet manufacturing apparatus are not required. Further, since the pellet manufacturing apparatus of the present invention has a configuration for cooling and hardening the strand in the forced cooling area and the natural cooling area, simplification and miniaturization of the cooling mechanism are possible. For this reason, the pellet manufacturing apparatus of the present invention is a pellet manufacturing apparatus that can be miniaturized as compared with a hot cut type pellet manufacturing apparatus.

[0032] Therefore, the pellet manufacturing apparatus of the present invention is a compact and easy-to-operate pellet manufacturing apparatus that can perform small-lot production including experiments, prototypes, etc. using a variety of resin materials.

Brief Description of the Drawings

[0033]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Figure 6

Figure 7

Figure 8

Figure 9

Figure 10

Mode for Carrying Out the Invention

[0034] Hereinafter, the pellet manufacturing apparatus and the method for manufacturing pellets of the present invention will be described based on the embodiments shown in the drawings. The embodiments described below do not limit the invention according to the scope of claims for utility model registration. Also, not all of the various elements and combinations thereof described in the embodiments are essential for the solution means of the present invention.

[0035] [Embodiment] 1. Pellet Manufacturing Apparatus 1 FIGS. 1 to 3 are diagrams shown to explain the pellet manufacturing apparatus 1 according to the embodiment. FIG. 1 can also be said to be an external view of the pellet manufacturing apparatus 1. FIG. 1(a) is a perspective view, FIG. 1(b) is a front view, and FIG. 1(c) is a left side view. FIG. 2 can also be said to be a diagram showing the inside of the pellet manufacturing apparatus 1. In FIG. 2, a part of the housing 80 (the top plate portion 82 and the side plate portion 84a in FIG. 1) is not shown. FIG. 2(a) is a perspective view, and FIG. 2(b) is a left side view. FIG. 3 can also be said to be a plan view and a cross-sectional view of the pellet manufacturing apparatus 1. FIG. 3(a) is a plan view, FIG. 3(b) is a cross-sectional view taken along the line A1-A1 of FIG. 3(a), and FIG. 3(c) is an enlarged cross-sectional view taken along the line A2-A2 of FIG. 3(a) regarding the cutting mechanism 70. In FIG. 3(b), the details of the structure that is not the key point of the invention, such as the internal structure of the motor, are omitted and simply shown.

[0036] FIG. 4 is a front view showing a state in which the pellet P is being manufactured by the pellet manufacturing apparatus 1 according to the embodiment. In FIG. 4, the illustration of the door portion 88 is omitted because if it is illustrated in the closed state, important components will be hidden, and it does not show that the door portion 88 is removed to carry out the manufacture of the pellet P. The same applies to FIG. 5. The thick arrows shown near the first forced cooling mechanism 40 and the second forced cooling mechanism 50 in FIG. 4 simply indicate the direction of the air flow and the discharge position. FIG. 5 is a cross-sectional view showing a state in which the pellet P is being manufactured by the pellet manufacturing apparatus 1 according to the embodiment. FIG. 5 is a cross-sectional view taken along the same cross-section as in the case of FIG. 3(b).

[0037] FIG. 6 is a front view shown to explain that the first forced cooling mechanism 40 and the second forced cooling mechanism 50 can change the direction of the air flow and the discharge position of the air flow in the pellet manufacturing apparatus 1 according to the embodiment. FIG. 6(a) is a front view showing a state where the states of the first forced cooling mechanism 40 and the second forced cooling mechanism 50 are the same as those in FIG. 1(b) and FIG. 4. FIG. 6(b) is a front view showing a state in which the direction of the air flow of the first forced cooling mechanism 40 and the second forced cooling mechanism 50 is changed to an acute angle compared to the case of FIG. 6(a). FIG. 6(c) is a front view showing a state in which the discharge position of the air flow of the first forced cooling mechanism 40 and the second forced cooling mechanism 50 is changed compared to the case of FIG. 6(a). In order to avoid complicating the drawing, in FIG. 6, the display of reference numerals other than the extrusion port 22, the first forced cooling mechanism 40, and the second forced cooling mechanism 50 in the pellet manufacturing apparatus 1 and the illustration of the door portion 88 are omitted. The thick arrows shown near the first forced cooling mechanism 40 and the second forced cooling mechanism 50 in FIG. 6 simply indicate the direction of the air flow and the discharge position.

[0038] The pellet manufacturing apparatus 1 according to the embodiment includes a charging mechanism 10, an extrusion mechanism 20, a first forced cooling mechanism 40, a second forced cooling mechanism 50, a feeding mechanism 60, a cutting mechanism 70, a housing 80, and a control mechanism 90 (see FIGS. 1 to 3). Note that the pellet manufacturing apparatus 1 may include components other than those described above. Hereinafter, each component will be described.

[0039] The charging mechanism 10 charges the resin material M into the extrusion mechanism 20. The charging mechanism 10 includes a hopper 12 that introduces the resin material M into the extrusion mechanism 20, and a hopper motor 14 for rotating the hopper 12. Further, the charging mechanism 10 further includes a stirring member 13 disposed near the inner surface of the hopper 12, a cylindrical member 16 disposed above the hopper 12, and a hopper driving force transmission mechanism 18 that transmits the driving force from the hopper motor 14 to the hopper 12. Therefore, the hopper 12 can rotate while the resin material M is charged.

[0040] Note that the "resin material" in this specification is a material for pellets mainly composed of a resin component. The resin material may be a mixture of an arbitrary additive or the like (for example, a coloring agent). As the resin component, any material that can be heated and melted can be used, and a plurality of types of resin components can also be used. Further, additives or the like other than the resin component may be solid or liquid.

[0041] The stirring member 13 is disposed near the inner surface of the hopper 12, but unlike the hopper 12, it does not rotate and is fixed to the housing 80. Due to the presence of the stirring member 13, the resin material M that moves as the hopper 12 rotates is stirred.

[0042] The extrusion mechanism 20 melts the resin material M and extrudes the resin material M from the extrusion port 22 in the direction DG along gravity to form a continuous rod-shaped strand S (see FIGS. 4 and 5). The number of extrusion ports 22 in the extrusion mechanism 20 is one, and with this configuration, the structure of the pellet manufacturing apparatus 1 can be simplified and miniaturized, and a configuration suitable for small-lot production can be achieved. Note that the pellet manufacturing apparatus 1 is configured such that the strand S moves from the extrusion port 22 of the extrusion mechanism 20 to the feeding mechanism 60 in a non-contact manner. The strand S mainly moves by gravity and the feeding by the feeding mechanism 60.

[0043] The extrusion mechanism 20 includes a screw 24 for kneading and extruding the resin material M, a hollow member 25 having an internal space for melting and kneading the resin material M, a nozzle 26 disposed at the tip of the hollow member 25 and having an extrusion port 22 formed at an end opposite to the hollow member 25 side, a screw motor 28 for rotating the screw 24, and a driving force transmission gear mechanism 29 for transmitting the driving force of the screw motor 28 to the screw 24. The screw 24 is disposed inside the hollow member 25 (see FIGS. 1 to 3).

[0044] The nozzle 26 is a bent nozzle having a substantially L-shaped internal flow path. The nozzle 26 does not necessarily have to be a bent nozzle, but by making the nozzle 26 a bent nozzle, the extrusion mechanism 20 can be accommodated in the space within the housing 80, which is advantageous for miniaturizing the pellet manufacturing apparatus 1. The hollow member 25 side of the nozzle 26 is disposed inside the housing 80, and the extrusion port 22 side is exposed outside the housing 80. It is preferable that the length of the nozzle 26 exposed outside the housing 80 is as short as possible. From this viewpoint, it is preferable that about 90% or more of the nozzle 26 is disposed inside the housing 80.

[0045] Note that the hollow member 25 and the nozzle 26 may be integrally formed as a member or may be separate members. When the hollow member 25 and the nozzle 26 are separate members, the nozzle 26 can be easily replaced and cleaned, so that effects such as improved maintainability and easy correspondence to changes in the resin material M can be obtained.

[0046] The driving force transmission gear mechanism 29 is a mechanism having one or more gears. The transmission of the driving force between the screw motor 28 and the screw 24 by the driving force transmission gear mechanism 29 is performed by gears. The driving force transmission gear mechanism 29 may also serve as a speed reduction mechanism. When the rotation axes of the screw motor 28 and the screw 24 are different as in the pellet manufacturing apparatus 1, a mechanism having a worm gear mechanism can be preferably used as the driving force transmission gear mechanism 29.

[0047] The extrusion mechanism 20 includes a first temperature adjustment mechanism 30 that adjusts the temperature on the side where the resin material M is introduced, and a second temperature adjustment mechanism 32 that adjusts the temperature on the side where the resin material M is melted. The first temperature adjustment mechanism 30 and the second temperature adjustment mechanism 32 each have a heater and a control mechanism. In FIGS. 2 and 3(b), reference numerals are shown for the heaters with respect to the first temperature adjustment mechanism 30 and the second temperature adjustment mechanism 32. The pellet manufacturing apparatus 1 includes two heaters for the first temperature adjustment mechanism 30 and one heater for the second temperature adjustment mechanism 32.

[0048] The first forced cooling mechanism 40 forcibly cools the strand S moving along the direction DG along gravity with an air flow. Further, the second forced cooling mechanism 50 is disposed on the side opposite to the first forced cooling mechanism 40 with respect to the path along which the strand S moves, and forcibly cools the strand S with an air flow together with the first forced cooling mechanism 40. The configurations of the first forced cooling mechanism 40 and the second forced cooling mechanism 50 are not particularly limited, but it is preferable to use those having high directivity of the generated air flow and being compact. As the portion that actually generates the air flow in the first forced cooling mechanism 40 and the second forced cooling mechanism 50, for example, a blower fan can be used, and preferably a blower fan can be used. The portion that actually generates the air flow in the first forced cooling mechanism 40 and the second forced cooling mechanism 50 is disposed outside the housing 80.

[0049] The pellet manufacturing apparatus 1 is configured to cool and harden the strand S by a forced cooling area C1 where the airflows from the first forced cooling mechanism 40 and the second forced cooling mechanism 50 directly hit the strand S, and natural cooling areas C2a and C2b where the airflows from the first forced cooling mechanism 40 and the second forced cooling mechanism 50 do not directly hit the strand S (see FIGS. 4 to 6).

[0050] In the pellet manufacturing apparatus 1, as natural cooling areas, there are a first natural cooling area C2a existing on the die opening 22 side with respect to the first forced cooling mechanism 40 and the second forced cooling mechanism 50, and a second natural cooling area C2b existing on the feeding mechanism 60 side with respect to the first forced cooling mechanism 40 and the second forced cooling mechanism 50 (see FIG. 6).

[0051] In the pellet manufacturing apparatus 1, when the length of the forced cooling area C1 on the movement path of the strand S is L1, and the lengths of the natural cooling areas C2a and C2b on the movement path of the strand S are L2, the relationship of "L1 ≦ L2" holds. In the pellet manufacturing apparatus 1, since the first natural cooling area C2a and the second natural cooling area C2b exist, the "length L2 of the natural cooling areas C2a and C2b" is the "sum of the length L2a of the first natural cooling area C2a and the length L2b of the second natural cooling area C2b". For this reason, in the pellet manufacturing apparatus 1, "L1 ≦ L2" can be expressed as "L1 ≦ L2a + L2b".

[0052] The first forced cooling mechanism 40 and the second forced cooling mechanism 50 can change at least one of the direction of the airflow and the discharge position of the airflow (see FIG. 6). The direction of the airflow can be changed, for example, by rotating the first forced cooling mechanism 40 and the second forced cooling mechanism 50 about a mounting member (not shown in the figure) to the housing 80 as an axis. Further, the discharge position of the airflow can be changed by changing the direction of the first forced cooling mechanism 40 and the second forced cooling mechanism 50 and mounting them to the housing 80.

[0053] Note that the first forced cooling mechanism 40 and the second forced cooling mechanism 50 may have a configuration that can change at least one of the direction of the airflow and the discharge position of the airflow without depending on the attachment member to the housing 80 or the attachment direction to the housing 80.

[0054] When the first forced cooling mechanism 40 and the second forced cooling mechanism 50 are controlled by the control mechanism 90, the change in the cooling situation when at least one of the direction of the airflow and the discharge position of the airflow is changed can be handled by the control via the control mechanism 90.

[0055] In the pellet manufacturing apparatus 1, even when at least one of the first forced cooling mechanism 40 and the second forced cooling mechanism 50 changes at least one of the direction of the airflow and the discharge position of the airflow, the relationship of "L1 ≦ L2" ("L1 ≦ L2a + L2b") holds. However, when at least one of the direction of the airflow and the discharge position of the airflow is changed, the positions and lengths of the forced cooling area C1 and the natural cooling areas C2a and C2b will change.

[0056] The feeding mechanism 60 is a mechanism for feeding the strand S. The feeding mechanism 60 includes a first feeding roller 62, a second feeding roller 64 for sandwiching the strand S between the first feeding roller 62, and a feeding roller motor 66 for rotating at least one of the first feeding roller 62 and the second feeding roller 64.

[0057] Also, at least one of the first feeding roller 62 and the second feeding roller 64 is configured to be movable. In the pellet manufacturing apparatus 1, the second feeding roller 64 is configured to be movable by a mechanism (not shown in the figure) that supports the second feeding roller 64.

[0058] The feeding mechanism 60 can adjust the moving speed of the strand S and the shape of the strand S by feeding the sandwiched strand S. For example, when changing the speed at which the feeding mechanism 60 feeds the strand S, the force pulling the still uncured strand S near the extrusion port 22 changes, so that the shape of the strand S (in this case, mainly the thickness) can be changed.

[0059] The cutting mechanism 70 cuts the strand S sent from the feeding mechanism 60 (see FIGS. 3(b), 3(c), 4, and 5). The cutting mechanism 70 includes a rotary blade 72 having a plurality of cutting blades arranged at the outer end of a rotatable base, a receiving blade 74 that serves as a receiver for the cutting blades, a motor 76 for rotating the rotary blade 72, and a cover 78 for preventing the pellets P from scattering.

[0060] An inlet 79 for passing the strand S is formed on the feeding mechanism 60 side of the cover 78 (see FIG. 3(c)). The end side surface on the feeding mechanism 60 side at the inlet 79 has a tapered shape. Also, the side of the cover 78 opposite to the feeding mechanism 60 is open, and the pellets P are discharged from the side opposite to the feeding mechanism 60 (see FIGS. 4 and 5). Although not shown, it is preferable to manufacture the pellets P with a container or the like arranged at the subsequent stage (downward) of the cutting mechanism 70.

[0061] Note that the strand S at the stage where the cutting mechanism 70 cuts is in a state where the moving path is determined (fixed) by the feeding mechanism 60. Therefore, the strand S is cut in a stable state.

[0062] The housing 80 has an extrusion mechanism 20, a first forced cooling mechanism 40, a second forced cooling mechanism 50, a feeding mechanism 60, and a cutting mechanism 70 disposed therein. In the pellet manufacturing apparatus 1, a charging mechanism 10 is also disposed in the housing 80. The arrangement positions of the respective components can be determined according to the structures and roles of the respective components. The housing 80 has a top plate portion 82, side plate portions 84a and 84b, a front plate portion 86, etc., and it is preferable that at least a part of each portion is openable / closable or detachable. Further, the housing 80 is openable / closable and has a door portion 88 that can cover the movement path of the strand S when closed.

[0063] Note that by manufacturing the pellets P with the door portion 88 closed, the airflows from the first forced cooling mechanism 40 and the second forced cooling mechanism 50 become reflected airflows by the front plate portion 86 and the door portion 88 to define the movement path of the strand S, so that the movement path of the strand S can be made more stable.

[0064] On the front of the housing 80, display mechanisms 91a and 91b for displaying the states, temperatures, etc. of the respective components (in the pellet manufacturing apparatus 1, the first temperature adjustment mechanism 30 and the second temperature adjustment mechanism 32), and operation mechanisms 92a, 92b, 92c, and 92d for operating the respective components are disposed. In the pellet manufacturing apparatus 1, the display mechanisms 91a and 91b are also provided with mechanisms (such as switches) for operating the first temperature adjustment mechanism 30 and the second temperature adjustment mechanism 32.

[0065] The control mechanism 90 is a mechanism that controls at least two or more of the extrusion mechanism 20, the first forced cooling mechanism 40, the second forced cooling mechanism 50, the feeding mechanism 60, and the cutting mechanism 70. Note that the control mechanism 90 may also control mechanisms other than those described above (for example, the charging mechanism 10). The control mechanism 90 is composed of, for example, an IC controller, a power supply, wiring, etc. Further, it is preferable that at least one of the display mechanisms 91a, 91b and the operation mechanisms 92a, 92b, 92c, 92d is connected to the control mechanism 90. The control mechanism 90 may, for example, individually control each mechanism according to an operation by a user, or may control a plurality of mechanisms automatically or semi-automatically. The control mechanism 90 may incorporate artificial intelligence (AI).

[0066] 2. Method for manufacturing pellets FIG. 7 is a flowchart of a method for manufacturing pellets according to an embodiment. Here, the method for manufacturing pellets according to the embodiment will be described. The method for manufacturing the pellets includes a melt extrusion step S10, a first natural cooling step S20, a forced cooling step S30, a second natural cooling step S40, a feeding step S50, and a cutting step S60 (see FIG. 7). Further, the method for manufacturing pellets according to the embodiment is a method for manufacturing pellets using the pellet manufacturing apparatus 1. The method for manufacturing pellets according to the embodiment may include steps other than those described above. Hereinafter, each step will be described.

[0067] The melt extrusion step S10 is a step of melting the resin material M and extruding the melted resin material M from the extrusion port 22 in the direction DG along the gravity to form a continuous rod-shaped strand S. The melt extrusion step S10 is carried out using the extrusion mechanism 20, the first temperature adjustment mechanism 30, and the second temperature adjustment mechanism 32.

[0068] The first natural cooling step S20 is a step of naturally cooling (slowly cooling) the strand S that moves non-contact along the direction DG along the gravity in the first natural cooling area C2a. In the first natural cooling step S20, the strand S passes through the first natural cooling area C2a.

[0069] The forced cooling step S30 is a step of forcibly cooling a strand S that moves non - contactingly along a direction DG along gravity by flowing air currents from both sides of the path along which the strand S moves. The forced cooling step S30 is carried out using a first forced cooling mechanism 40 and a second forced cooling mechanism 50.

[0070] The second natural cooling step S40 is a step of naturally cooling (slowly cooling) a strand S that moves non - contactingly along a direction DG along gravity in a second natural cooling area C2b. In the second natural cooling step S40, the strand S passes through the second natural cooling area C2b.

[0071] The feeding step S50 is a step of feeding the cooled strand S. The feeding step S50 is carried out using a feeding mechanism 60. In the feeding step S50, the strand S is sandwiched by a first feeding roller 62 and a second feeding roller 64 of the feeding mechanism 60, and the strand S is fed by the rotation of at least one of the first feeding roller 62 and the second feeding roller 64. Also, in the feeding step S50, by feeding the strand S, the moving speed of the strand S and the shape of the strand S can be adjusted.

[0072] The cutting step S60 is a step of cutting the strand S into pellets P. The cutting step S60 is carried out using a cutting mechanism 70.

[0073] By carrying out the above steps, pellets P can be manufactured from the resin material M. Note that the method for manufacturing pellets according to the embodiment includes a melt extrusion step S10, a first natural cooling step S20, a forced cooling step S30, a second natural cooling step S40, a feeding step S50, and a cutting step S60. Conceptually, only one of the first natural cooling step S20 and the second natural cooling step S40 may be sufficient. The first natural cooling step S20 and the second natural cooling step S40 can also be summarized as the "natural cooling step".

[0074] 3. Prototype machine and pellets manufactured by the prototype machine FIG. 8 is a photograph showing an actual machine corresponding to the pellet manufacturing apparatus 1 according to the embodiment and the pellets manufactured by the actual machine. FIG. 8(a) is a photograph of the actual machine, and FIG. 8(b) is a photograph of the pellets.

[0075] Note that the inventors of the present invention have already completed an actual machine corresponding to the pellet manufacturing apparatus 1 according to the embodiment (see FIG. 8(a)). The actual machine of the pellet manufacturing apparatus is very compact and easy to operate as a pellet manufacturing apparatus (about 250 mm in width, about 500 mm in depth, and about 700 mm in height). In addition, it is possible to produce a small lot of high-quality pellets with uniform particle sizes (for example, production in units of 100 g for experimental and trial purposes) using a variety of resin materials (see FIG. 8(b)).

[0076] 4. Effects of the Pellet Manufacturing Apparatus and the Pellet Manufacturing Method The pellet manufacturing apparatus 1 according to the embodiment includes the above-described extrusion mechanism 20, a first forced cooling mechanism 40, a second forced cooling mechanism 50, a feeding mechanism 60, a cutting mechanism 70, and a housing 80. Further, the pellet manufacturing apparatus 1 according to the embodiment is configured such that the strand S moves from the extrusion port 22 of the extrusion mechanism 20 to the feeding mechanism 60 in a non-contact manner, and the strand S is cooled and cured by the forced cooling area C1 and the natural cooling areas C2a and C2b.

[0077] Therefore, according to the pellet manufacturing apparatus 1 according to the embodiment, the mechanism for moving the strand S and the cooling mechanism can be made extremely compact, the installation, movement, and operation of the apparatus can be facilitated, the quality of the pellets P can be improved, the movement path of the strand S can be stabilized even without a guide for conveyance or the like, and the apparatus can be miniaturized as compared with a pellet manufacturing apparatus using a hot cut method.

[0078] Therefore, the pellet manufacturing apparatus 1 according to the embodiment is a pellet manufacturing apparatus that is compact, easy to operate, and capable of small lot production including experiments, trial productions, etc. using a variety of resin materials M.

[0079] Also, in the pellet manufacturing apparatus 1 according to the embodiment, the extrusion mechanism 20 has a driving force transmission gear mechanism 29. Therefore, according to the pellet manufacturing apparatus 1 according to the embodiment, it is possible to transmit the driving force from the screw motor 28 to the screw 24 with a highly efficient and compact mechanism.

[0080] Further, the pellet manufacturing apparatus 1 according to the embodiment includes a charging mechanism 10, and the charging mechanism 10 has a hopper 12 and a hopper motor 14. Therefore, according to the pellet manufacturing apparatus 1 according to the embodiment, it is possible to eliminate the clogging of the resin material M in the hopper 12 without using vibration or a complicated mechanism.

[0081] Also, in the pellet manufacturing apparatus 1 according to the embodiment, the extrusion mechanism 20 has a first temperature adjustment mechanism 30 and a second temperature adjustment mechanism 32. Therefore, according to the pellet manufacturing apparatus 1 according to the embodiment, it is possible to subdivide the temperature management in the extrusion mechanism 20, and as a result, it is possible to suppress the clogging of the resin material M and the poor melting of the resin material M.

[0082] Also, in the pellet manufacturing apparatus 1 according to the embodiment, the feeding mechanism 60 has a first feeding roller 62, a second feeding roller 64, and a feeding roller motor 66. Further, in the pellet manufacturing apparatus 1, at least one of the first feeding roller 62 and the second feeding roller 64 is configured to be movable. Therefore, according to the pellet manufacturing apparatus 1 according to the embodiment, it is possible to stably feed the strand S while adjusting the shape of the strand S to a shape suitable for cutting.

[0083] Also, in the pellet manufacturing apparatus 1 according to the embodiment, there are a first natural cooling area C2a and a second natural cooling area C2b as natural cooling areas. Therefore, according to the pellet manufacturing apparatus 1 according to the embodiment, it is possible to suppress the airflow from the first forced cooling mechanism 40 and the second forced cooling mechanism 50 from directly hitting the extrusion port 22, and it is possible to suppress the defects and clogging of the strand S due to the temperature drop of the extrusion port 22.

[0084] Further, in the pellet manufacturing apparatus 1 according to the embodiment, when the length of the forced cooling area C1 on the moving path of the strand S is L1 and the lengths of the natural cooling areas C2a and C2b on the moving path of the strand S are L2, the relationship of "L1 ≤ L2" holds. Therefore, according to the pellet manufacturing apparatus 1 according to the embodiment, it is possible to sufficiently lengthen the lengths of the natural cooling areas C2a and C2b and stably cool the strand S.

[0085] Further, in the pellet manufacturing apparatus 1 according to the embodiment, the first forced cooling mechanism 40 and the second forced cooling mechanism 50 can change at least one of the direction of the air flow and the discharge position of the air flow. Therefore, according to the pellet manufacturing apparatus 1 according to the embodiment, it is possible to change the positions and lengths of the forced cooling area C1 and the natural cooling areas C2a and C2b according to the characteristics of the resin material M and the shape of the strand S, etc., and to change the timing and ratio of rapid cooling and slow cooling.

[0086] For example, by rapidly cooling polycarbonate and acrylic, crystallization inside the resin can be suppressed and transparency can be increased. On the other hand, for crystalline resins such as polypropylene and polyethylene, the crystal structure develops by slow cooling, so the mechanical properties are improved. According to the pellet manufacturing apparatus 1, by making it possible to change the timing and ratio of rapid cooling and slow cooling, it is possible to flexibly and appropriately respond according to the characteristics (properties of the resin material M) for each type of resin material M and the desires of the user, etc.

[0087] Further, in the pellet manufacturing apparatus 1 according to the embodiment, the extrusion mechanism 20 has a hollow member 25 and a nozzle 26, and the portions that actually generate the air flow among the first forced cooling mechanism 40 and the second forced cooling mechanism 50 are arranged outside the housing 80. The nozzle 26 has the hollow member 25 side arranged inside the housing 80 and the extrusion port 22 side exposed outside the housing 80. Therefore, according to the pellet manufacturing apparatus 1 according to the embodiment, it is possible to separate the nozzle 26 from the first forced cooling mechanism 40 and the second forced cooling mechanism 50 by the housing 80, and it is possible to suppress defects and clogging of the strand S due to a temperature drop of the nozzle 26.

[0088] In addition, according to the pellet manufacturing apparatus 1, since it is possible to suppress a temperature drop of the nozzle 26 even when a strong air flow is generated by the first forced cooling mechanism 40 and the second forced cooling mechanism 50, compared with a pellet manufacturing apparatus in which the entire nozzle or a member corresponding thereto is exposed (for example, the pellet manufacturing apparatus described in Patent Document 3), it is possible to improve the cooling capacity.

[0089] Further, according to the pellet manufacturing apparatus 1 according to the embodiment, since the control mechanism 90 is provided, it is possible to make the apparatus compact and simple by integrating the control system.

[0090] The method for manufacturing pellets according to the embodiment includes a melt extrusion step S10, a natural cooling step (a first natural cooling step S20 and a second natural cooling step S40), a forced cooling step S30, a feeding step S50, and a cutting step S60. Therefore, the method for manufacturing pellets according to the embodiment is a method for manufacturing pellets that can manufacture the pellets P in small lots from a wide variety of resin materials M while making the mechanism for moving the strand S and the cooling mechanism extremely compact.

[0091] As described above, the present invention has been described based on the above embodiments, but the present invention is not limited to the above embodiments. It can be implemented in various modes without departing from the gist thereof, and for example, the following modifications are also possible.

[0092] (1) The positions, sizes, shapes, etc. of the respective components described in the above embodiments and shown in the respective drawings are examples, and can be changed within a range that does not impair the effects of the present invention.

[0093] (2) The pellet manufacturing apparatus 1 according to the above embodiment includes two heaters for the first temperature adjustment mechanism 30 and one heater for the second temperature adjustment mechanism 32, but the present invention is not limited thereto. The number and positions of the heaters of each temperature adjustment mechanism can be arbitrarily determined according to the specifications of the product, etc.

Explanation of Reference Numerals

[0094] 1... pellet manufacturing apparatus, 10... feeding mechanism, 12... hopper, 13... stirring member, 14... motor for hopper, 16... cylindrical member, 18... driving force transmission mechanism for hopper, 20... extrusion mechanism, 22... extrusion port, 24... screw, 25... hollow member, 26... nozzle, 28... motor for screw, 29... driving force transmission gear mechanism, 30... first temperature control mechanism, 32... second temperature control mechanism, 40... first forced cooling mechanism, 50... second forced cooling mechanism, 60... feeding mechanism, 62... first feeding roller, 64... second feeding roller, 66... motor for feeding roller, 70... cutting mechanism, 72... rotary blade, 74... receiving blade, 76... motor for rotary blade, 78... cover, 79... inlet, 80... housing, 82... top plate portion, 84a, 84b... side plate portions, 86... front plate portion, 88... door portion, 90... control mechanism, 91a, 91b... display mechanism, 92a, 92b, 92c, 92d... operation mechanism, DG... direction along gravity, M... resin material, P... pellet, S... strand

Claims

1. an extrusion mechanism that melts a resin material and extrudes the resin material from an extrusion port in a direction along gravity to form a continuous rod-shaped strand; a first forced cooling mechanism that forcefully cools the strand moving along the gravity direction with an air flow; a second forced cooling mechanism that is disposed on an opposite side to the first forced cooling mechanism with respect to a path along which the strand moves, and that, together with the first forced cooling mechanism, forcibly cools the strand with an airflow; a feeding mechanism for feeding the strand; a cutting mechanism that cuts the strand fed from the feeding mechanism; A pellet manufacturing apparatus comprising: a housing in which the extrusion mechanism, the first forced cooling mechanism, the second forced cooling mechanism, the feeding mechanism, and the cutting mechanism are disposed, The pellet manufacturing apparatus is characterized in that the strand is configured to move without contact from the extrusion port of the extrusion mechanism to the feed mechanism, and the strand is configured to be cooled and hardened by a forced cooling area where the air currents from the first forced cooling mechanism and the second forced cooling mechanism directly hit the strand, and a natural cooling area where the air currents from the first forced cooling mechanism and the second forced cooling mechanism do not directly hit the strand.

2. 2. The pellet manufacturing apparatus according to claim 1, wherein the extrusion mechanism includes a screw for kneading and extruding the resin material, a screw motor for rotating the screw, and a driving force transmission gear mechanism for transmitting a driving force from the screw motor to the screw.

3. a feeding mechanism for feeding the resin material into the extrusion mechanism, 2. The pellet manufacturing apparatus according to claim 1, wherein the feeding mechanism includes a hopper for introducing the resin material into the extrusion mechanism, and a hopper motor for rotating the hopper.

4. 2. The pellet manufacturing apparatus according to claim 1, wherein the extrusion mechanism has a first temperature adjustment mechanism for adjusting the temperature of a side where the resin material is fed, and a second temperature adjustment mechanism for adjusting the temperature of a side where the resin material is melted.

5. The feed mechanism includes: a first feed roller, a second feed roller for sandwiching the strand between the first feed roller and the second feed roller, and a feed roller motor for rotating at least one of the first feed roller and the second feed roller, 2. The pellet manufacturing apparatus according to claim 1, wherein at least one of the first feed roller and the second feed roller is configured to be movable.

6. The pellet manufacturing apparatus according to claim 1, characterized in that the natural cooling areas include a first natural cooling area located on the extrusion port side of the first forced cooling mechanism and the second forced cooling mechanism, and a second natural cooling area located on the feed mechanism side of the first forced cooling mechanism and the second forced cooling mechanism.

7. 2. The pellet manufacturing apparatus according to claim 1, wherein when the length of the forced cooling area on the movement path of the strand is L1 and the length of the natural cooling area on the movement path of the strand is L2, the relationship "L1≦L2" holds.

8. 2. The pellet manufacturing apparatus according to claim 1, wherein the first forced cooling mechanism and the second forced cooling mechanism are capable of changing at least one of a direction of the air current and a discharge position of the air current.

9. the extrusion mechanism further includes a hollow member having an internal space for melting and kneading the resin material, and a nozzle that is disposed at a tip of the hollow member and has the extrusion port formed at an end portion opposite to the hollow member side, a portion of the first forced cooling mechanism and a portion of the second forced cooling mechanism that actually generates the airflow are disposed outside the housing, 2. The pellet manufacturing apparatus according to claim 1, wherein the nozzle is disposed inside the housing on the side of the hollow member, and the extrusion port side is exposed to the outside of the housing.

10. 2. The pellet manufacturing apparatus according to claim 1, further comprising a control mechanism for controlling at least two or more mechanisms among the extrusion mechanism, the first forced cooling mechanism, the second forced cooling mechanism, the feeding mechanism, and the cutting mechanism.

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