JPH05261726A - Resin pelletizer - Google Patents

Abstract

PURPOSE:To provide a resin pelletizer capable of suppressing the adhesion of a resin to a cutter or a nozzle die and capable of certainly and stably performing the cutting operation of a resin and capable of keeping a high treatment efficiency. CONSTITUTION:A resin pelletizer is equipped with an extruder 2 extruding a resin from a nozzle die 7 in a molten state, a movable cutter 22 for cutting the strand-shape resin P extruded from the nozzle die 7, a fixed cutter 24 and a cutter driving means 20 reciprocally moving the movable cutter 22 to intermittently perform the cutting operation of the resin P. A guide member 15 preventing the shaking of the strand-shape resin P immediately after extruded from the nozzle die 7 to guide the same to the cutters 22, 24 is provided at the position spaced apart by a specified distance from the nozzle die 7 between the nozzle 7 and the cutters 22, 24 and the strand-shape resin P passing through the guide member 15 is cut by the cutters 22, 24.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a pelletizer for resin which cuts a resin in a heated and molten state extruded through a nozzle die of an extruder into pellets.

[0002]

2. Description of the Related Art Conventionally, a cold cut method (strand cut method) has been used as a method of extruding a molten resin by extruding it from a nozzle die (extrusion head) of an extruder while heating and melting the resin, and processing and processing the extruded molten resin into pellets. (Also called method) and hot cut method are known. In the cold cut method, molten resin is extruded from a nozzle die of an extruder in a strand shape (thin rod shape), the extruded resin is cooled through a cooling water tank, and then cut with an appropriate cutter. In this method, even a resin with a high melt viscosity can be completely cooled and hardened by elongating the cooling water tank, etc., so that there is a problem that the resin adheres to the cutter or the cut pelletized resins are welded to each other. Although it is less likely to occur, it requires a cooling water tank to be installed between the extruder nozzle die and the cutter, increasing the installation area of the device and breaking the resin extruded into a strand before it is cut by the cutter. Therefore, there is a disadvantage that a repairing process or the like is required and the processing efficiency is likely to be low.

On the other hand, in the hot cut method, a rotary cutter is arranged near the nozzle die of the extruder,
Since the molten resin immediately after being extruded from the nozzle die of the extruder is cut by the cutter, the apparatus can be made relatively compact and the processing efficiency can be kept high. However, the conventional resin pelletizer, which is designed to cut the molten resin into pellets by this hot-cut method, usually has a nozzle die of an extruder in which a plurality of nozzle holes are arranged on the same pitch circle at predetermined angular intervals. The extrusion surface of the nozzle die located on the outlet side of the nozzle hole is formed into a flat surface while being arranged in an array, and the rotary cutter is arranged so that its rotation axis is orthogonal to the extrusion surface, and the blade edge thereof is the extrusion surface. It is rotated so as to draw a plane parallel to the nozzle die, and in order to cool the resin extruded from the nozzle die, a cooling medium (water, air, etc.) is jetted from the outside of the nozzle die toward the nozzle die. ..

In the conventional resin pelletizer having such a structure, the injection port of the cooling medium and the extruded molten resin are relatively separated from each other, and moreover, the cooling medium is directly blown to the nozzle die or to the cutter. Since it may be blocked, the extruded molten resin itself may be insufficiently cooled or the nozzle die may be excessively cooled, and moreover, a plurality of nozzle holes may be formed along the rotation direction of the cutter. As it is arranged so that it overlaps when viewed, the molten resin extruded from each nozzle hole is cut one after another in the order along the rotation direction of the cutter and is discharged in the rotation direction of the cutter, but cooling is performed. Since it is often insufficient, there has been a problem that the cut resins are welded to each other to form a lump or adhere to a cutter or a nozzle die.

Further, for example, Japanese Patent Laid-Open No. 59-178208.
In order to solve the above-mentioned problems, in the publication, a plurality of nozzle holes are formed in a row at a predetermined interval in a nozzle die having a flat extrusion surface, and the rotation axis of a rotary cutter is arranged in the direction of arrangement of the nozzle holes. Dispose of the molten resin extruded from each nozzle hole by scraping with a cutter at about the same time, then cool the resin adhering to the cutter and strike the cutter against the claws. There has been proposed a pelletizer for resin, which is designed to remove the adhered resin.

However, in such a hot-cutting device for resin, the rotary cutter is used to scrape off the molten resin extruded from the nozzle hole, and the rotary cutter is made to collide with the scraping claw to scrape off the resin. To achieve this, it is necessary for the rotary cutter to have appropriate elasticity and rigidity, and as a result, the structure and material of the rotary cutter becomes complicated and expensive, and it is also necessary to remove the adhered resin. Since a relatively large impact is applied to the blade edge of the rotary cutter when it is dropped, there is a drawback that the cutter is easily damaged and its life cannot be maintained for a long time.

Therefore, in order to solve the problems associated with the conventional pelletizer for resin as described above, the inventor of the present application has previously described, for example, as described in Japanese Patent Application No. 3-329015. We proposed a new pelletizer for resin. In the resin pelletizer, a main part of the pelletizer will be schematically described. As shown in FIGS. 7 and 8, the nozzle die 102 of the extruder 100 has a plurality of nozzle holes 103.
Are arranged at regular intervals from the front to the back in the figure, and the strand-shaped resin P extruded from the respective nozzle holes 103 simultaneously is reciprocally moved by the cutter driving means 110. Cutter 120
It is supposed to be cut by. Cutter driving means 110
Has a drive mechanism section (not shown) and a swing arm 121 swingable by the drive mechanism section.
The guide pin 123 fixed to the slider 125 is fitted into the elongated hole 122 formed in the first slot. Above slider 1
25 is slidably supported by two guide rods 127 extending in the horizontal direction, and the movable cutter 120 is fixed to the slider 125.

Therefore, when the cutter driving means 110 is driven, the swing arm 121 swings in the left-right direction in the figure, and the movable cutter 120 is horizontally moved with a slight gap left on the lower end pushing surface of the nozzle die 102 accordingly. It reciprocates so that it is pushed out and pulled from it.
The movable cutter 120 intermittently cuts the resin P extruded from each nozzle hole 103 from a direction orthogonal to the resin P each time it reaches a predetermined length.

In the resin pelletizer having such a structure, the resin P extruded is cut by reciprocating the cutter instead of rotating it. Therefore, the conventional resin pelletizer using a rotary cutter is used. In comparison with the above, the degree of freedom of installation of the cooling medium injection means for cooling the extruded resin P, the cutter, etc. is increased
It becomes possible to dispose the cooling medium jetting means at or near the cutter or the nozzle die itself. Therefore, the extruded resin P and the cutter can be cooled extremely reasonably and efficiently, and the problem that the nozzle die is excessively cooled can be avoided. Moreover, the resins cut by the cutter will naturally fall according to gravity while keeping a certain distance, so that the situation in which the cut pellet-shaped resins are welded to each other to form a lump can be reduced. It also becomes.

[0010]

However, even in the cutter reciprocating type resin pelletizer having the above-mentioned advantages, the following points should be improved if the resin pelletizer is actually prototyped and operated. It became clear. That is, the molten resin extruded from the nozzle die is cut by the cutter when it reaches a certain length, but the tip of the extruded resin is a free end, so that it easily shakes. Therefore, the cutting position of the resin by the cutter should be as close as possible to the extrusion surface of the nozzle die from the viewpoint of the reliability and stability of the cutting operation, and therefore, only a small gap is formed between the cutter and the extrusion surface of the nozzle die. I can't.

However, when the cutter is arranged near the extruding surface of the nozzle die, the cutting position of the resin by the cutter becomes a high temperature portion which is not yet sufficiently cooled immediately after being extruded from the nozzle die. Therefore, heat is conducted from the resin immediately after being extruded to the cutter that repeats the cutting operation, and the temperature of the cutter rises. When the cutter becomes hot, the extruded resin easily adheres to the cutter, the cut resin does not separate from the cutter, the cutting operation does not progress, and the cutter and nozzle die are not far apart, so the extruded resin Adheres to the nozzle die. When the resin adheres to the nozzle die, heat is conducted from the nozzle die to the cutter via the resin, the temperature of the cutter further rises, and the amount of resin adhered is increased.

As described above, when the resin adheres to the cutter and the nozzle die, the cutting operation is not smoothly performed and a large number of cutting defects occur, the extruded resin becomes a lump, the nozzle hole is clogged, Problems such as a hindrance to cooling occur, and repair processing is required, resulting in reduced processing efficiency. It should be noted that, as described above, the problem similarly occurs in the conventional resin pelletizer using the rotary cutter, since there is not so much gap between the cutter and the nozzle die.

In view of the above point, the present invention is capable of suppressing the adhesion of the resin to the cutter or the nozzle die, and surely and stably cutting the resin, thereby maintaining the high processing efficiency. An object is to provide a pelletizer for resin.

[0014]

In order to achieve the above object, a resin pelletizer according to the present invention is arranged such that a cutter is placed away from a nozzle die, and the extruded resin is located at a position apart from an extruded surface of the nozzle die to some extent. It is characterized in that a guide member is provided to prevent the resin from shaking due to the resin cutting position being separated from the nozzle die.

Specifically, an extruder having a nozzle die provided with nozzle holes and adapted to extrude the resin in a molten state from the nozzle die, and the strand-shaped resin extruded from the nozzle die are cut. In addition to the basic configuration including a cutter for cutting and a cutter driving unit that causes the cutter to intermittently perform the cutting operation of the strand-shaped resin, a predetermined distance is provided between the nozzle die and the cutter and from the nozzle die. At a position separated by a distance of, a guide member is provided which guides to the cutter side while preventing the swaying of the strand-shaped resin immediately after being extruded from the nozzle die. It will be cut by.

In a preferred embodiment of the present invention, a cooling medium injection means for cooling the resin immediately after being extruded from the nozzle die is provided in the nozzle die or in the vicinity thereof, or the cutter is reciprocated by the cutter driving means. And the like. Also,
When adopting a method of reciprocating the cutter, a fixed cutter is provided in front of the reciprocating movable cutter so that the strand-shaped resin can be sandwiched between the movable cutter and the movable cutter. And the fixed cutter cooperate to cut the resin.

[0017]

[Operation] In the resin pelletizer according to the present invention configured as described above, the strand resin extruded from the nozzle die is guided to the cutter side while being prevented from shaking by the guide member and cut. It In this case, since the cutter is separated from the nozzle die with the guide member sandwiched therebetween, the cut portion of the extruded resin is located not at the vicinity of the extrusion surface of the nozzle die but at a certain distance from it. Therefore, since the cut portion of the resin is cooled from the portion near the nozzle die, the amount of heat conducted to the cutter at the time of cutting is reduced, and the temperature rise of the cutter is suppressed.

As a result, the cutter is maintained at a lower temperature than the conventional one, the extruded resin does not adhere so much at the time of cutting, and the cutting operation is performed smoothly. In addition, since the cutter is separated from the nozzle die and the guide member is interposed between them, resin does not adhere to the nozzle die, and heat can hardly be conducted from the nozzle die to the cutter. ..

When the resin is cut by the cutter,
Since the vicinity of the cut portion of the resin is supported by the guide member, undesired shaking of the resin is prevented, and the cutting operation is performed reliably and stably. By doing so, defective cutting does not occur so much, the situation where the cut resin becomes clumped or the nozzle hole is blocked can be avoided, and the cooling of each part can be performed reasonably and efficiently. It becomes possible and the processing efficiency is remarkably improved.

[0020]

Embodiments of the present invention will be described below with reference to the drawings. 1 and 2 schematically show a main part of an embodiment of a resin pelletizer according to the present invention.
The resin pelletizer 1 has an extruder 2, and the extruder 2 is provided with a screw conveyor 3 as a conveying and extruding means. A stirring blade 5 is provided on the conveying end side of the screw conveyor 3, and a nozzle die 7 having a discharge nozzle 10 is provided below the stirring blade 5. As shown in FIG. 2, a plurality of (four in this case) nozzle holes 11 are formed in the discharge nozzle 10 at predetermined intervals along the horizontal direction with their outlet-side openings facing vertically downward. ing.

Although not shown, a heater is arranged around the extruder 1 so that the crushed thermoplastic resin is fed from the hopper or the like to the conveying start end side of the extruder 1. It has become. The extruder 1 further crushes the charged resin by a screw conveyor 3 while heating and melting the resin, and conveys the resin, and a discharge nozzle 10 provided in a nozzle die 7.
1, the molten resin is extruded in a strand form to the outside (vertically downward) through the nozzle hole 11.

Further, the nozzle die 7 is provided with a cooling medium jetting means for cooling the nozzle die 7 and for cooling the strand-shaped resin P extruded from the nozzle die 7. The cooling medium injection means supplies a distribution passage 13 formed in the nozzle die 7, a plurality of injection ports 13 opening downward from the distribution passage 13, and a cooling medium (air, water, mist, etc.) from the outside to the distribution passage 13. A hose 16, a nipple 14, etc. for

A guide member 15 for guiding the strand-shaped resin P extruded from the nozzle hole 11 is arranged below the nozzle die 7, and a plate-shaped movable cutter 22 and a fixed cutter are provided below the guide member 15. 24 is provided. The guide member 15 is fixed in a substantially horizontal state to the upper ends of brackets 29 mounted near the tips of two guide rods 47 that slidably support a slider 45 of a cutter driving means 20 described later.
A portion of the guide member 15 located directly below the discharge nozzle 10 has a cup-shaped cross section that expands upward.
Guide long hole 1 extending along the arrangement direction of the two nozzle holes 11
7 are formed.

On the other hand, as shown in detail in FIG. 3, the movable cutter 22 and the fixed cutter 24 constituting the resin cutting means are arranged such that the fixed cutter 24 is positioned on the movable cutter 22 and a strand-like shape is formed between them. The resin P is sandwiched and cut. More specifically, the movable cutter 22 has a rectangular plate shape, and a concave portion 23 that is concave inward is formed in the front portion, and the end surface of the concave portion 23 has a cutting edge 22a.
It is said that. The blade edge 22a is the movable cutter 2
It is formed to be inclined by an angle β with respect to the front and rear end faces of No. 2. The movable cutter 22 is fixed to a slider 45 described later and is reciprocated along a horizontal direction as indicated by a white arrow in FIG. 1, and the recess 23 on the front side of the movable cutter 22 is reciprocated. Fixed to 2
The cutting edge of 4 is placed.

The fixed cutter 24 is fixed to the lower surface side of a swinging member 26 in which a bearing portion 28 formed at one end side is rotatably coupled by a pin 27 to a bracket 29 supporting the above-mentioned guide member 15. The swinging member 26
It is constantly urged toward the movable cutter 22 by two coil springs 25 which are compressed between the guide member 15 and the guide member 15.

Therefore, the movable cutter 22 is reciprocated so as to slide on the lower surface side of the fixed cutter 24, and the movable cutter 22 and the fixed cutter 24 cooperate to cut the strand-shaped resin P extruded. To be done. The cutter driving means 20 for reciprocating the movable cutter 22 is provided with a geared motor 30 (FIG. 5) as a drive source, as shown in FIGS. 4 and 5, and a drive shaft 31 of the motor 30 has a disc-like shape. The cam 32 is connected and fixed. A deformed elliptical cam groove 33 is formed in the cam 32 in a state of being eccentric from the center of rotation thereof, and the crank pin 35 is slid in the cam groove 33 so as to slide therein.
Is loosely fitted. As shown in FIG. 4, the cam groove 33 has a distance a from the rotation center 0 of the cam 32 to one apex on the minor axis side and a distance a to the other apex.
It is set to be longer b, and the distances from the center of rotation to the two vertices on the major axis side are made equal.

The crank pin 35 is connected to the cam side arm 3
4 is coupled to one end side of the cam side arm 34, and the other end side of the cam side arm 34 is rigidly coupled to a connecting pin 36 pivotally supported by a bracket 38 fixed to the wall portion 9 so as not to be relatively rotatable. Further, on the side opposite to the arm of the connecting pin 36, the swing arm 4 having a racetrack-shaped guide hole 42 formed on one end side is formed.
The other end side of 1 is rigidly coupled so that it cannot rotate relative to each other.

Therefore, the cam side arm 34 and the swing arm 4
1 always performs a motion similar to the elevation motion according to the rotation of the cam 32 with the connecting pin 36 as the center of rotation while maintaining the crossing angle α. Then, the guide hole 42 of the swing arm 41
Is a roller 43 attached to the tip of a pin 44 screwed to a slider 45 to which the movable cutter 22 is fixed.
Is rotatably inserted. The slider 45 is supported by a bracket 48 attached to the wall 9 and is slidably supported by two guide rods 47 extending in the horizontal direction.

In the cutter driving means 20 having such a structure, when the cam 32 is rotated by the motor 30, the crank pin 35 slides in the cam groove 33, and accordingly, the cam arm 34 and the cam side arm 34 swing. Arm 4
1 swings around the connecting pin 36 while maintaining the intersection angle α, and the state shown in FIG. 4 and the state shown in FIG. 6 (shown by the solid line and the alternate long and short dash line in FIG. 1). And are taken alternately. At this time, the side circumference of the guide hole 42 is the roller 4
3 is pushed, the slider 45 is guided by the guide rod 47 with the movable cutter 22 and moves in the horizontal direction, and the movable cutter 22 is extruded from the nozzle die 7 together with the fixed cutter 24. The P is sandwiched so as to be intermittently cut from a direction orthogonal thereto.

In the resin pelletizer of the present embodiment configured as described above, the strand-shaped resin P extruded from the nozzle die 7 is guided to the cutters 22 and 24 side while being prevented from shaking by the guide member 15. You will be guided and disconnected. In this case, since the cutters 22 and 24 are separated from the nozzle die 7 with the guide member 15 interposed therebetween, the cut portion of the resin P extruded is the extruded surface of the nozzle die 7 (the tip of the nozzle hole 11 of the discharge nozzle 10). ) It is not a neighborhood, but some distance away from it. Therefore, the cut portion of the resin P is cooled to such an extent that at least the outer surface of the cut portion is hardened by the cooling medium or the like ejected from the ejection port 13. Cutters 22 and 24 when cutting
The amount of heat conducted to the blades is reduced, and the temperature rise of the cutters 22 and 24 is suppressed.

As a result, the cutters 22 and 24 are maintained at a lower temperature than conventional ones, the extruded resin P does not adhere so much at the time of cutting, and the cutting operation is performed smoothly. In addition, since the cutters 22 and 24 are separated from the nozzle die 7 and the guide member 15 is interposed between them, the resin does not adhere to the nozzle die 7, and the cutter 22 and the cutter 22, Little heat can be conducted to 24.

Further, when the resin P is cut by the cutters 22 and 24, since the vicinity of the cut portion of the resin P is supported by the guide member 15, undesired shaking of the resin is prevented, and the cutting operation is reliable and stable. Will be done. Further, since the fixed cutter 24 is pressed against the movable cutter 22 by the coil spring 25, the resin P attached to the movable cutter 22 is also scraped off by the fixed cutter 24.

By doing so, defective cutting does not occur so much, the situation in which the cut resin P becomes clumped or the nozzle hole 11 is blocked is avoided, and the cooling of each part is rational and possible. It can be performed efficiently, and the processing efficiency is significantly improved. In addition, in the above-mentioned example, the one in which the movable cutter 22 is reciprocated is used as the cutter driving means 20, but the invention is not limited to this, and the present invention can be applied to one in which the cutter is rotated. .. Further, as a mechanism for reciprocating the cutter, in addition to the mechanism using the above-mentioned cam, for example, a mechanism using a fluid pressure cylinder, a mechanism using a link mechanism similar to a quick return mechanism of a machine tool, etc. You may use.

[0034]

As is apparent from the above description, in the resin pelletizer according to the present invention, since the cutter is separated from the nozzle die with the guide member interposed therebetween, the strand-shaped resin extruded at the time of cutting. The amount of heat conducted from the cutter to the cutter is reduced, and the temperature rise of the cutter is suppressed. As a result, the cutter is maintained at a lower temperature than the conventional one, the extruded resin does not adhere so much at the time of cutting, and the cutting operation is smoothly performed. In addition, since the cutter is separated from the nozzle die and the guide member is interposed between them, the resin does not adhere to the nozzle die, and when the resin is cut by the cutter, the resin is cut. Since the vicinity of the portion is supported by the guide member, undesired shaking of the resin can be prevented, and the cutting operation can be performed reliably and stably.

Therefore, in the resin pelletizer of the present invention, the cutting failure does not occur so much, and the situation where the cut resin becomes lumpy or the nozzle hole is clogged is avoided,
It is possible to cool each part rationally and efficiently, and it is possible to obtain the effect of significantly improving the processing efficiency.

[Brief description of drawings]

FIG. 1 is a side view showing a main part of an embodiment of a resin pelletizer according to the present invention.

2 is a front view of the embodiment shown in FIG.

FIG. 3 is a perspective view showing a movable cutter and a fixed cutter of the embodiment of FIG.

FIG. 4 is a side view provided for explaining an entire configuration including a cutter driving unit of the embodiment shown in FIG. 1 and an operation thereof.

FIG. 5 is a front view for explaining the entire configuration including the cutter driving means of the embodiment shown in FIG. 1 and its operation description.

FIG. 6 is a side view for explaining the overall operation including the cutter driving means of the embodiment shown in FIG.

FIG. 7 is a side view of a main part of a conventionally proposed resin pelletizer.

8 is a side view provided for explaining the operation of the conventional example shown in FIG.

[Explanation of symbols]

 1-Pelletizer for resin 2-Extruder 3-Screw conveyor 7-Nozzle die 10-Discharge nozzle 11-Nozzle hole 13-Cooling medium injection port 15-Guide member 20-Cutter drive means 22-Movable cutter 24-Fixed cutter 25-Coil Spring 30-Motor 32-Cam 41-Swinging arm 45-Slider 47-Guide rod P-Stranded resin

Claims (4)

[Claims] 1. An extruder having a nozzle die provided with a nozzle hole, and an extruder adapted to extrude a resin in a molten state from the nozzle die, and a cutter for cutting a strand-shaped resin extruded from the nozzle die. And a cutter drive means for causing the cutter to intermittently perform the operation of cutting the strand-shaped resin, in a resin pelletizer, the distance between the nozzle die and the cutter and a predetermined distance from the nozzle die. At the position, a guide member for preventing the swaying of the strand-shaped resin immediately after being extruded from the nozzle die and guiding it to the cutter side is provided, and the strand-shaped resin passing through this guide member is cut by the cutter. Pelletizer for resin, which is characterized by 2. The resin hot-cutting apparatus according to claim 1, wherein a cooling medium jetting means for cooling the resin immediately after being extruded from the nozzle die is provided at or near the nozzle die. 3. The resin pelletizer according to claim 1, wherein the cutter driving means is configured to reciprocate the cutter. 4. A fixed cutter is provided on the front side of the reciprocating movable cutter so that the strand-shaped resin can be sandwiched between the movable cutter and the movable cutter, and the movable cutter and the fixed cutter cooperate with each other. The resin pelletizer according to claim 3, wherein the resin pelletizer is configured to cut the resin.