KR200183571Y1 - Apparatus for manufacturing foamed thermoplastic resin pellets - Google Patents

Abstract

The present invention is a pellet-type thermoplastic that can be continuously and inexpensively formed in a pellet form in a thermoplastic resin such as low density polyethylene (PE) or polypropylene (PP), which has a simple structure and does not emit pollution gas during incineration. The present invention relates to an apparatus for producing a resin foam, and in particular, to continuously form a linear foam in a pellet form, so that a smooth and uniform process can be performed smoothly and uniformly without noise, vibration, frictional heat, and airflow. An object of the present invention is to provide an apparatus for producing pelletized thermoplastic foams which can be produced continuously with high productivity.

In one embodiment of the present invention for achieving the above object is a die that is press-supplied from the inlet side to the inside in the state that the thermoplastic resin and the blowing agent are melt-mixed, and a plurality of radial extrusion holes 23 are formed on the cylindrical outlet side (11), a top feed (17) coupled to one end is fixed to the outlet end of the die 11 and the other end is extended to the inner center of the die 11, and the extrusion hole of the die 11 Means 25 for cutting and forming linear foam extruded through the radially extruded holes 23 of the die 11 into pellet-shaped resin foams of a predetermined size, which are installed on the outside of the portion where the portions 23 are formed. It is configured to include, so that the means 25 is in close contact with the outer peripheral surface of the portion where the radial extrusion holes 23 of the die 11 is formed to extend in a spiral along the curved surface of the outer peripheral surface It provides a device for producing a pellet-type thermoplastic resin foam, characterized in that consisting of a plurality of cutting steel wire 30 is installed.

Description

Apparatus for manufacturing pellet-type thermoplastic resin foam {APPARATUS FOR MANUFACTURING FOAMED THERMOPLASTIC RESIN PELLETS}

The present invention relates to an apparatus for producing a pellet-type thermoplastic resin foam, in particular a die for extruding and foaming a resin material in the radial direction of the cylindrical body and means for continuously cutting and forming the extruded foam from the die into pellets of uniform size and shape. The present invention relates to an apparatus for producing a pellet-type thermoplastic resin foam having a relatively high viscosity thermoplastic resin so as to be able to form a large amount of continuous foam inexpensively in a small pellet form.

Pellet-type thermoplastic foam has good moldability to products with complex shapes, and features excellent cushioning and durability against repeated impact, hard and smooth surface, excellent chemical resistance and moisture resistance. It is widely used for molding products for various applications such as carrying cases, cushioning materials for shock absorption, cushioning materials for vehicles, buoys, and the like.

Conventionally, such thermoplastic resin foams are usually polystyrene, or a copolymer of polystyrene and other resins is used to cut linear resin melt-extruded into pellets after water cooling to produce foamed resin pellets as intermediate products. It was prepared by a method of foam molding to a final foam through a foam molding process including. This manufacturing method has been commonly used because it is easy to manufacture pellets, but once the foamable resin pellets have to be made through a two-step manufacturing process of foam molding again, the overall process and equipment are complicated, and using The use of these products is increasingly regulated because they emit pollutant gases when incinerated.

Therefore, in recent years, thermoplastic resin pellets are manufactured using materials such as low density polyethylene (LDPE), linear low density polyethylene (L-LDPE), polypropylene (PP), and the like as thermoplastic resin materials that do not emit polluting gases. Doing.

Since the thermoplastic resin pellets have a high viscosity of resin materials such as LDPE and L-LDPE, they are difficult to be manufactured by conventional cutting methods, and the foaming agent is mixed with plastic particles in a small amount of individual reaction method, and foamed after heating and pressing. Was manufacturing.

To explain this in more detail, the resin pellets are made according to the expansion ratio and the size of the foamed particles, and many small resin pellets are put in the drum container to add the foaming agent, and then heated to a temperature below the melting point. At the same time, it is pressurized to high pressure and kneaded for several minutes (5-30 minutes), and then foamed particles are intermittently obtained by opening and foaming after the foaming agent has sufficiently infiltrated the resin particles. Therefore, such a small amount of foaming method has a problem that it is difficult to continuously mass-produce the production cost of the foam particles, as well as the size of the foam particles pellets is not uniform.

In general, foams such as polystyrene are not difficult to produce in pellet form, but thermoplastic resins such as low density polyethylene and linear low density polyethylene and polypropylene have high viscosity and are difficult to cut into pellets. The bur is cut in the form of remaining, it is not possible to obtain a good quality pellets and there is a problem that the uniformity is greatly reduced. Therefore, there is a great demand for a means that can economically and practically achieve uniform pelletization while continuously foaming thermoplastic resin having high viscosity.

Accordingly, the present inventors enable continuous foam molding in pellet form while mixing and extruding thermoplastic resin and foaming agent so that the desired pellet-type thermoplastic resin foam can be continuously molded directly from the resin material without forming a separate foamable intermediate product. The device has been researched and patented as Korean Patent No. 135899. The present invention further improves the manufacturing performance of the desired foam by further improving it.

The patent application is a die in which the thermoplastic resin and the blowing agent are melt-mixed and press-supplied from the inlet side to the inside, and a plurality of radial extrusion holes are formed at the outlet side, and one side is fixed to the outlet side end of the die. And a spindle-shaped top feed coupled to the other side so as to extend to the inner center of the die, and a linear foam that is rotatably coupled to the outer side of the die to be extruded and foamed through radial extrusion holes of the die. And a cutter for forming a resin foam, wherein the cutter includes plate-shaped blades which tangentially contact an outer circumferential surface of a die in which the radial extrusion holes are formed. It is describing.

However, this apparatus has been found to have the following problems in use due to the use of a rotary cutter having a plate-like blades in contact with the length of the die on the outer peripheral surface of the cylindrical die as described above.

First, it is very difficult to install the blades correctly to smoothly perform the required cutting operation because the blades should be installed on the outer circumferential surface of the cylindrical die along the length of the die. If the replacement of the blade is required there is a problem that takes a long time to replace the work.

Secondly, the blade blade structure is rotated along the die surface with the blade blade contacting the die surface without any gap, and the blade blade receives the impact force repeatedly repeatedly when cutting the extrudate by the blade blade. Since the work is made, the blade blades are prone to wear and breakage prematurely, and the noise and vibration are severe.

Third, the use of the plate blades as described above causes severe frictional heat due to the contact rotation between the die and the blades, and at the same time, the air flow due to the rotating plate blades acts on the die and the extrudate through the die, thereby extruded and foaming the resin. Since the conditions are liable to fluctuate unstable, it is difficult to obtain an optimum good foaming condition, and at the same time, the shape of the foam pellets is irregular due to the influence of airflow by the rotating blades.

The present invention has been made in order to effectively improve the problems and disadvantages of the prior patent invention as described above to provide a device capable of exhibiting the production performance of a more excellent pellet-type thermoplastic resin foam.

1 is a cross-sectional view of a pellet-type thermoplastic resin foam manufacturing apparatus according to an embodiment of the present invention,

Figure 2 is an enlarged cross-sectional view of the excerpts of Figure 1,

3 is a general configuration diagram of an apparatus according to another possible embodiment of the present invention;

4 is an enlarged view of a die portion of the apparatus of FIG. 3;

5 is an enlarged cross-sectional view of the excerpts of the apparatus of FIG.

FIG. 6 is a cross-sectional view along the direction A-A in FIG. 4; FIG.

Explanation of symbols on the main parts of the drawings

1,11: Dies 2,17: Top feed 3: Resin flow path

4,23: extrusion hole 5: working rod 6a, 6b: hole

7: cutting surface 8: inclined surface 9: driving motor

10: extruder 13: die inlet 14: hollow part

25: pellet-shaped resin foam cutting molding means 26, 27: ring portion

28: bearing 29: holder 30: cutting steel wire

31: shaft 32: eccentric cam 33: crank

34: support plate 35: connecting rod

In one embodiment of the present invention for achieving the above object is a die that is press-supplied from the inlet side to the inside in the state that the thermoplastic resin and the blowing agent is melt-mixed, and a plurality of radial extrusion holes formed in the cylindrical outlet side, One side is fixed to the exit side end of the die and the other end is coupled to the other side extending to the inner center of the die and a radial extrusion hole of the die is installed outside the radial extrusion hole formed in the die And means for cutting and molding the linear foam that is extruded and foamed through the pellet into a pellet resin foam having a predetermined size, and the cutting molding means of the pellet resin foam is formed on the outer circumferential surface of the die in which the radial extrusion holes are formed. Plurality installed so as to extend in a spiral along the curved surface of the outer circumference It provides a device for producing a pelletized thermoplastic foam, characterized in that consisting of cutting steel wires.

In another possible embodiment of the present invention that can achieve the above object, the die and the die which is supplied therein in a state that the thermoplastic resin and the foam is melt-mixed and a plurality of radial extrusion holes are formed on the cylindrical outlet side, A top feed formed in the inner center of the plurality of resin flow paths radially disposed between the outer circumferential surface and the inner circumferential surface of the cylindrical body of the die at a predetermined interval, and a predetermined distance to the cylindrical body of the die along the respective resin flow paths; A plurality of extrusion holes provided in a radial direction with respect to each other, and a resin disposed at a portion where radial extrusion holes of the die body are formed to be extruded through radial extrusion holes of the die pellets of a constant size A means for cutting and molding into a resin foam; The radially extruded holes of the die body are arranged to reciprocate in one direction or the opposite direction along the length of the die and alternately to two adjacent extrusion holes on the die body according to the vibrations. It provides a manufacturing apparatus of the pelletized thermoplastic resin foam comprising a plurality of operating rods formed with a plurality of pairs of holes communicated with the driving means, and driving means for vibrating the operating rods during operation of the device. do.

Hereinafter, the present invention will be described in more detail with reference to the accompanying drawings.

First, the thermoplastic resin which can be applied in the present invention is conventional polystyrene, styrene-acrylonitrile interpolymer and styrene-ethylene interpolymer, and the like, low density and linear low density polyethylene, polypropylene, ethylene-propylene interpolymer, ethylene-vinyl acetate hybrid Polymers, polyvinyl chloride, and the like, and those made of interpolymers alone or in combination may be used.

In addition, a blowing agent applied to the present invention may be used a volatile or degradable blowing agent. Examples of the highly volatile blowing agent include aliphatic hydrocarbons such as propane, butane, isobutane, and pentane, substituted aliphatic hydrocarbons such as cyclobutane, cyclopentane, and cyclohexane, methyl chloride, methylene chloride, dichlorofluoromethane and chlorotri Fluoromethane, dichlorodifluoromethane and the like can be used, and dinitrosopentamethylenetetraamine, trinitrosotrimethylenetriamine, benzene sulfonylhydrazide, azodicarbonamide and the like can be used as the degradable blowing agent. These blowing agents can be used independently or in combination.

The thermoplastic resin, the blowing agent and other additives, etc., are made into the thermoplastic resin foam mixture by passing through an extruder.

That is, in the extruder configured by inserting a mixer between the main extruded part and the cold extruded part, the thermoplastic resin raw material is first supplied to the main extruded part and melted and transferred to the mixer by screw operation. The blowing agent is uniformly dispersed and mixed in the thermoplastic resin by indentation, mixing and stirring.

According to the kind of thermoplastic resin raw material, the main extrusion part is used, for example, in the case of low-density polyethylene, adjusted to a temperature of 100-200 ° C., and the mixer is set at the maximum temperature and pressure.

Thereafter, the foam mixture is continuously foamed in pellet form by the apparatus of the present invention as shown in FIGS. 1-2 or 3-6.

1 to 2 show the configuration of an apparatus according to an embodiment of the present invention. The device is a die 11 having an inlet 13 coupled to an outlet of the extruder 10 and having a hollow portion 14 therein, and one side of which is fixed to the outlet side of the die 11 and the other side of a die ( A top feed 17 provided in the die 11 and a cylindrical outlet side outer periphery of the die 11 so as to extend to the inner center of the hollow portion 14 of the hollow portion 14). And a means 25 for continuously cutting the linear foam extruded through the plurality of radially perforated extrusion holes 23 into pellets of a predetermined length.

In the illustrated embodiment, the die 11 has a first body in which the inlet 13 is coupled to the outlet side of the extruder 10 and has an inner groove 11B for receiving the centering support 27 of the top feed 17. 11A and a second body 11C, which is coupled to the top feed 17 to extend through the inner center thereof, and has a plurality of extrusion holes 23 bored in the radial direction at the body, and the first body. The inlet side is inserted into the outlet inner diameter of the first body 11A and the outer protruding flange to connect the body 11A and the second body 11C and at the same time to fix the centering support 27 of the top feed 17. The third body 11D, which is additionally bolted to the outlet side of the first body 11A, the outer periphery of the tip end of the second body 11C, is screwed inside the outlet side, and the outer periphery of the tip end of the first body 11A. It is configured to include a coupling ring 11E screwed to the bolted to the outlet of the extruder 10.

As shown in Fig. 2, the pellet-shaped resin foam cutting means 25 is rotatably installed on the outer circumference of the cylindrical outlet side of the die 11 through a bearing 28, and is provided by a plurality of fasteners 29. The curved surface of the outer circumferential surface on a cylindrical outlet side outer circumferential surface having radially extruded holes 23 of the die 11 between the two ring portions 26 and 27 fixed to each other and the ring portions 26 and 27 being fixed to each other. It is configured to include a plurality of cutting steel wires 30 are connected to be installed to be in close contact with the spiral. In a preferred embodiment, each cutting steel wire 30 is fixed at one end thereof in place of one ring portion 26 and the other end is about 180 from the wire connection point of the one ring portion 26 at the other ring portion 27. The means 25 are connected to each other in a biased position, and the means 25 is preferably configured by connecting and installing a total of four or more steel wires 30 between the ring portions 26 and 27 as described above.

At the rear end of the means 25, a power transmission means 31 for rotating the entire means 25 around the second body 11C of the die 11 in accordance with a rotational driving source (not shown), for example, a motor. ) Is connected and installed.

In operation, when the foam mixture from the extruder 10 is fed through the inlet 13 of the die 11, the foam mixture is compressed, expanded, through a passage between the top feed 17 and the inner circumferential surface of the die 11. It is conveyed to the exit side of the die 11 while undergoing a compression process.

Thereafter, the foam mixture is linearly extruded through a plurality of extrusion holes 23 radially formed at the outlet side of the die 11 and simultaneously foamed, and the foam thus extruded is rotated by an unillustrated rotational drive source. The pellets are cut into pellets by the cutting steel wires 30 of the rotary resin pellet-forming foam cutting means 25 so that the thermoplastic resin foam in pellet form is continuously obtained.

When the means 25 is rotated, the cutting steel wires 30 connected as described above between the ring portions 26 and 27 of the means 25 are provided with the extrusion holes 23 of the die 11. Since the foam is continuously cut along the outer circumferential surface of the cylindrical portion and continuously extruded through the extrusion holes 23, the foam is gradually obliquely with respect to the foam without being subjected to the vertical shear pressure with respect to the foam. Due to the shear force acting, the cutting is performed very smoothly. Accordingly, the operation of continuously cutting the linear foam from the extruded port 23 into pellets of a predetermined size is performed on the plate-shaped blade acting perpendicular to the foam as in the prior art. Very quiet and smooth with little noise or vibration caused by shear shock and extremely uniform size and shape It is obtained. In addition, since cutting steel wires 30 having a diameter of about 0.3 to 2.0 mm proceed in a spiral manner, the cutting action is performed as described above, so that friction heat and airflow are not generated as in the case of conventional plate blades. It is easy to maintain a constant setting of the foaming conditions in an optimal state and has the advantage of minimizing the deformation of the pellets due to airflow.

Furthermore, Figures 3 to 6 show the configuration of a device according to another possible embodiment of the present invention, which is a die 1 consisting of a hollow cylindrical body and a seat in the inner center of the die 1. A top feed (2) forming a plurality of resin flow paths (3) disposed radially at regular intervals between the outer circumferential surface and the cylindrical body inner circumferential surface of the die (1), and along the respective resin flow paths (3) Arranged in a portion where a plurality of extrusion holes 4 provided in a radial direction at regular intervals in the cylindrical body of the die 1 and radial extrusion holes 4 in the body of the die 1 are formed. And means for continuously cutting molding the resin extruded through the radial extrusion holes 4 of the die 1 into pellet-shaped resin foams of a predetermined size, the means being the length of the die 1 One direction along the direction Or a plurality of pairs of holes 6a and 6b which are arranged to reciprocate in the opposite direction and alternately communicate with two mutually adjacent extrusion holes 4 on the body of the die 1 according to the vibrations. It is composed of a configuration including the driving rods 5 and the driving means for achieving the vibrating movement of the operating rods (5) formed.

During the vibrating movement of the actuating rod 5, a pair of dies 6a and 6b paired with each other on the actuating rod 5 are arranged so as to be in communication with the two extruded holes 4 adjacent to each other. 1) The outer end of each of the extruded holes 4 on the body cooperates with the outer end of each of the holes 6a and 6b on the operating rod 5 to form a linear extrudate through the holes 6a and 6b. A cutting surface 7 is formed to cause a cutting action, and an outer side of each cutting surface 7 is provided with an inclined surface 8 for smooth cutting and discharging of the extrudate.

There may be various means in the means for vibrating the operating rods 5 as the present invention aims. One possible example for this is the rotational operation by the drive motor 9 as illustrated in FIG. A circular eccentric cam 32 is installed on the rotation shaft 31, and a crank 33 is connected to the eccentric cam 32 by bearing one end of the same crank 33, and the operating rod 5 is installed. Means of connecting the connecting rod 35 between the center of the support plate 34 and the end of the crank 33 by fixing the end of the crank 33 side to the one support plate 34. Can be mentioned. In Fig. 3, the connecting state of the connecting rod 35 is shown in a schematic manner, but the eccentric rotational movement of the eccentric cam 32 on the rotation shaft 31 and the crank along the rotational movement of the eccentric cam 32 ( The connection between the connecting rod 35 and the support plate 34 is made via a connecting means such as a universal joint, in order to enable the swinging movement of 33 to be transmitted in a linear reciprocating motion of the operating rods 5. .

In the action of the apparatus according to the embodiment of Figs. 3 to 6, the resin material mixed with the blowing agent is a resin flow path (3) between the die (1) and the top feed (2) located in the center of the die (1). The extrusion holes 4 and the holes on the operating rod 5 which are press-fitted into the dies 1 and then penetrated to the respective resin flow paths 3 in a radial direction through the die 1 body. It is extruded out of the die 1 through 6a) and 6b. At this time, if one of the two adjacent holes 6a and 6b on the operating rod 5 is in communication with one of the extruded holes 4 on the body of the die 1, the remaining holes adjacent thereto are 6a is blocked by a wall between two adjacent extrusion holes 4 on the body of the die 1 including the extrusion holes 4, so that the extrusion of the resin material through them is temporarily stopped.

At the same time, when the driving motor 9 is operated, the rotary shaft 31 is rotated by receiving the rotational force of the driving motor 9, and thus the eccentric cam 32 installed on the rotary shaft 31 is rotated ( 31, while the eccentric rotation around the central axis of the crank 33 is connected to this rocking movement, the rocking movement of the crank 33 is connected to the support plate 34 through the connecting rod (35) The operating rods 5 having end portions connected to and fixed to the support plate 34 are to be reciprocated in the drawing body in a reciprocating direction. In accordance with the vibration movement of these operating rods 5, two adjacent holes 6a and 6b on each operating rod 5 are alternately communicated with two adjacent extrusion holes 4 on the die body. At this time, through the hole 6a or the hole 6b on the operating rod 5 connected to the extrusion hole 4 of the die 1 body, the resin material is extruded and linearly foamed outward from the die 1. The linear extruded foam, which is extruded in this manner, meets the cutting surface 7 located on the outer circumferential surface of the body of the die 1 in accordance with the vibrating motion of the operating rod 5, and thus the vibration speed of the operating rod 5. It is cut into pellets of a corresponding size and then discharged out of the die 1. Since a large number of radially extruded holes 4 along each resin flow path 3 are formed in a plurality of radial positions on the body of the die 1, a large amount of pellets is used for each vibration movement of the operating rods 5. The type thermoplastic resin foam is formed and discharged outside the die 1.

On the other hand, when the resin extrudate extruded out of the die 1 through the holes 6a and 6b of the operating rod 5 is cut by the cutting surface 7, the cutting surface 7 is cut into the extrudate. Since the extrudate is cut while gathering the inward parts, the pellets cut out and re-extruded outside the die 1 have an extremely uniform shape at both ends of the cut and minimize the rupture or spreading at the cutting end of the pellet. Good quality pellets with a hard coat are obtained.

Therefore, according to the present invention as described above, the desired pellet-type thermoplastic resin foam can be molded continuously in a large quantity without a separate foamable intermediate product molding process, and high viscosity foam resin, which has been difficult to foam foam in the past, has been difficult to form. Also, continuous foaming is possible in the form of pellets, and noise, vibration, frictional heat, and airflow are hardly generated by means of continuously cutting the foam into pellets, thereby further improving the quality and uniformity of the product. Lose.

Claims (2)

A die 11 in which the thermoplastic resin and the blowing agent are melt-mixed and press-supplied from the inlet side to the inside thereof, and a plurality of radial extrusion holes 23 are formed at the cylindrical outlet side, and the outlet end of the die 11; One end is fixed to and the other end is installed on the outside of the portion where the top feed 17 is coupled and installed so as to extend to the inner center of the die 11, the extrusion hole 23 of the die 11 is formed And means (25) for continuously cutting and molding the linear foam extruded through the radial extrusion holes (23) of the die (11) into pellet-shaped resin foam of a predetermined size, wherein the means (25) (11) characterized in that it consists of a plurality of cutting steel wires (30) are installed to be in close contact with the outer circumferential surface of the portion where the radial extrusion holes (23) are formed along the curved surface of the outer circumferential surface Pellet manufacturing apparatus of thermoplastic resin foam with. 2. A device according to claim 1, wherein the device is located radially between the die 1 having a cylindrical body and at an inner center of the die 1 between its outer circumferential surface and the cylindrical body inner circumferential surface of the die 1; A plurality of top feeds (2) forming a plurality of resin flow paths (3), and a plurality of radially formed provided at regular intervals in the cylindrical body of the die (1) along each resin flow path (3) The resin to be extruded through the extrusion holes 4 and the radial extrusion holes 4 of the die 1 is disposed at a portion where the extrusion holes 4 in the die 1 body are formed. And means for continuously cutting into pellet-shaped resin foams of size, said means being arranged to allow reciprocating vibrations in one direction or the opposite direction along the longitudinal direction of said dice 1 and oscillating motions thereof. Based on Operating rods 5 having a plurality of pairs of holes 6a, 6b alternately communicating with two mutually adjacent extrusion holes 4 on the body of the die 1, and vibrations of the operating rods 5; Apparatus for producing a pellet-type thermoplastic resin foam, characterized in that it comprises a drive means arranged to effect movement.