JP3485358B2 - Extrusion molding equipment - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an extrusion molding apparatus, and more particularly to an extrusion molding apparatus for performing desired resin molding by discharging molten resin supplied by an extruder from a discharge port of a die.

[0002]

2. Description of the Related Art Generally, a resin material such as a thermoplastic resin fed from an hopper by an extruder is melted while being transported by a screw conveyor in a closed cylinder, and then the molten resin is melted into a die having a predetermined shape. There is often used an extrusion molding apparatus that extrudes the molten resin from the discharge port of the die and discharges the molten resin into a desired shape.

FIG. 6 shows a die of such a conventional extrusion molding apparatus. A die 1 of the extrusion molding apparatus has a cylindrical mandrel 3 integrally formed on the center of the upper surface of a disk-shaped base 2. And a cylindrical main body 4 engaged with the mandrel 3 so as to have a slight gap on the outer peripheral side. Between the outer peripheral surface of the mandrel 3 and the inner peripheral surface of the main body 4, there is formed an annular resin flow passage 6 through which the molten resin 5 from an extruder (not shown) is fed so as to gradually narrow the flow passage. A plurality of spirally formed resin grooves are formed on the outer peripheral surface of the mandrel 3 forming the resin path 6, and the upper end of the resin flow path 6 serves as a discharge port 7 for the resin 5. There is. Further, a feed port 8 connected to the extruder is formed in the center of the lower surface of the base portion 2, and the upper end of the feed port 8 and the lower end of the resin groove 6 are arranged in the radial direction. Are connected by a resin introduction path 9 extending to the. Then, the molten resin 5 supplied from the extruder is discharged from the discharge port 7 through the feed port 8 of the die 1, the resin introduction path 9, and the resin flow path 6, respectively.

An air jet 10 is formed in the center of the mandrel 3 of the die 1 so as to open to the inside of the discharge port 7. The air jet 10 is provided inside the mandrel 3. An air communication path 11 communicating with each other is formed. Further, on the lower surface of the die 1, the air conducting path 1
1. An air supply port 12 communicating with 1 is formed. By sending air from the air supply port 12 and ejecting air from the air ejection port 10 via the air conduction path 11,
The resin 5 discharged from the discharge port 7 is blown up.

Further, above the die 1, an annular cooling air supply device 13 for cooling the resin 5 by ejecting cooling air to the outer periphery of the resin 5 which is cylindrically discharged from the discharge port 7 is arranged. Further, a pair of guide plates 14, 14 for guiding the resin 5 discharged in a cylindrical shape from the discharge port 7 so as to be folded into a flat shape is disposed above the die 1. . A pair of pinch rollers 15, 15 that pulls up and conveys the planar resin 5 folded by the guide plate 14 is disposed at the upper position of each of the guide plates 14. On the downstream side, a cutter 16 is provided which cuts both sides of the resin 5 to separate the tubular resin 5 into two planar resins 5. Further, in the vicinity of the cutter 16, a pair of conveying rollers 17, 17 for separately conveying the separated resin 5 is arranged.

In the conventional extrusion molding apparatus, the molten resin 5 supplied from the extruder is fed through the feed port 8 of the die 1.
From the discharge port 7 through the resin introduction path 9 and the resin flow path 6 and is discharged upward, and the air is sent from the air supply port 12.
Air is ejected from the air ejection port 10 at a predetermined pressure via 1 to blow up the resin 5 ejected from the ejection port 7. Then, the discharged resin 5 is cooled by the cooling air blown from the cooling air supply device 13 and gradually pulled up by the guide plate 14 into a planar shape while being pulled up by the pinch roller 15, and then the cutter. Both side portions of the resin 5 are cut by 16 to separate the tubular resin 5 into two planar resins 5, and the transport rollers 17 individually transport the separated resins 5 to predetermined positions. It is supposed to do.

However, in the conventional extrusion molding apparatus, when the resin 5 is molded, if the resin 5 is solidified in a natural state, there is a problem that the surface of the resin 5 is crystallized. When the surface of No. 5 is irradiated with external light, there is a problem that the external light is diffusely reflected by the crystal and the transparency of the resin 5 is significantly impaired.
Therefore, the use of the molding resin 5 is limited, and the commercial value of the molding resin 5 is reduced.

FIG. 7 shows a conventional means for increasing the transparency of the molding resin in order to solve such a problem. The pair of rolling rolls 18 and 18 have a gap size of the film thickness of the resin 5 after molding. The rolled roll 18 is arranged so as to have a smaller gap size, the rolled roll 18 is heated at a temperature lower than the melting point of the resin 5 and higher than the softening point, and the resin 5 after molding is placed between the rolling rolls 18. By inserting and rolling the resin 5, the film thickness of the resin 5 is reduced and the surface irregularities are removed, and the transparency of the resin 5 is increased.

FIG. 8 shows another conventional means for increasing the transparency of the molded resin. A pair of rolled plates 19 and 19 having mutually smooth surfaces are formed with a gap of resin 5 between them. The thickness of the rolled plate 19 is smaller than that of the rolled plate 19 and the rolled plate 19 is maintained at a constant temperature. The smooth surface removes the unevenness of the surface of the resin 5 and enhances the transparency of the resin 5.

[0010]

However, in any of the conventional means for increasing the transparency of the molding resin, the resin 5 after being molded by the extrusion molding device is used in any means.
Since the secondary processing is performed on the resin, it takes a lot of time and effort to increase the transparency of the resin 5, and the rolling roll 1
8 requires a separate device such as the rolling plate 8 and the rolling plate 19, which raises the problem of high manufacturing cost.

Further, the precision of the rolling roll 18, the surface precision of the smooth surface of the rolling plate 19, and the like, and the rolling roll 18
There is a problem that the transparency of the resin 5 varies depending on the control temperature of the rolling plate 19 or the rolling plate 19, and it is extremely difficult to perform processing so that the transparency of the resin 5 becomes uniform.

The present invention has been made in view of the above points, and an object of the present invention is to provide an extrusion molding apparatus capable of easily molding a resin having high transparency without secondary processing. It is a thing.

[0013]

In order to achieve the above object, an extrusion molding apparatus according to the present invention is provided with an extruder for melting and extruding a predetermined resin, and the molten resin is formed into a tubular shape in the extruder. A die having a discharge port for molding and discharging is connected, and an air discharge port is formed at the center of the die to blow air into the resin discharged from the discharge port to blow the resin. In the extrusion molding device, an inner heating plate that forms the inner peripheral surface of the discharge port formed in an annular shape so as not to close the air ejection port on the upper surface of the die and inside the discharge port is provided , An outer peripheral surface of the ejection port , which is an upper surface of the die and is formed in a ring shape outside the ejection port, is formed.
An outer heating plate is provided, and heaters are attached to the inner heating plate and the outer heating plate.

Preferably, a heat insulating plate is provided between the inner heating plate and the outer heating plate and the upper surface of the die, and the die is provided with a heat insulating plate portion of the outer heating plate and the outside. It is characterized in that an air escape hole communicating therewith is formed. Further, preferably, a heat exchanger for exchanging heat with the temperature adjusting medium by a predetermined refrigerant is provided, and a medium pipe for circulating the temperature adjusting medium from the heat exchanger to each heat insulating plate portion is provided. Further, a temperature sensor is arranged on each of the heat insulating plate portions, and a temperature controller for adjusting the temperature of the temperature control medium based on the temperature detected by the temperature sensor is arranged on the heat exchanger. It is characterized by being installed.

[0015]

According to the extrusion molding apparatus of the present invention, the heater is energized when resin molding is performed.
By energizing this heater, the inner heating plate and the outer heating plate are respectively heated, and the molten resin passing between the inner heating plate and the outer heating plate from the discharge port is heated by the inner heating plate and the outer heating plate. The inner and outer surfaces are heated instantaneously. By this heating, the surface of the molten resin is smoothed and discharged, and since the surface of the discharged molten resin is smoothed, light from the outside may be irregularly reflected. Without
The transparency can be increased. Further, if a heat insulating plate is provided between the inner heating plate and the outer heating plate and the upper surface of the die, heat of the inner heating plate and the outer heating plate by the heater is less likely to be transferred to the die. By forming an air escape hole,
The heat dissipation effect of the heat insulating plate can be enhanced. Further, the temperature of the heat insulating plate can be controlled by circulating the temperature control medium that has been heat-exchanged by the heat exchanger through each heat insulating plate portion through the medium pipe.

[0016]

Embodiments of the present invention will be described below with reference to FIGS.

FIG. 1 shows an embodiment of a die of an extrusion molding apparatus according to the present invention, in which the same parts as in the prior art are designated by the same reference numerals. The die 1 of the extrusion molding apparatus has a cylindrical mandrel 3 integrally formed at the center of the upper surface of a disk-shaped base 2.
On the outer peripheral side of the mandrel 3, a cylindrical main body 4 having an inner diameter having a slight gap with respect to the outer peripheral surface of the mandrel 3 is provided from the lower surface of the base 2 to the lower surface of the main body 4. It is fitted and fixed by a fixing screw 20 which is screwed into. In addition, the outer peripheral surface of the mandrel 3 and the main body 4
An annular resin flow channel 6 is formed between the inner peripheral surface of the resin flow path 6 and the inner peripheral surface thereof, and the upper end of the resin flow channel 6 serves as a discharge port 7 for the resin 5. Further, a feeding port 8 for feeding the molten resin 5 from the extruder is formed in the center of the lower surface of the base 2, and the upper end of the feeding port 8 and the lower end of the resin flow path 6 are formed. The parts are connected by a resin introducing passage 9 extending in the radial direction. Then, the molten resin 5 supplied from the extruder is discharged from the discharge port 7 through the feed port 8 of the die 1, the resin introduction path 9, and the resin flow path 6, respectively.

An air jet 10 is formed in the center of the mandrel 3 of the die 1 so as to open to the inside of the discharge port 7. The air jet 10 is provided inside the mandrel 3. An air communication path 11 communicating with each other is formed. Further, on the lower surface of the die 1, the air conducting path 1
1, an air supply port 12 communicating with 1 is formed, air is sent from the air supply port 12, and air is ejected from an air ejection port 10 via the air conduction path 11 to eject the air.
The resin 5 discharged from is blown up.

Further, in the present embodiment, the upper surface of the die 1 and the inside of the discharge port 7 are formed in an annular shape so as not to close the air ejection port 10, and a recess 21 is formed in the central portion of the upper surface. An inner heating plate 22 is provided,
An annular outer heating plate 23 having an outer diameter similar to that of the die 1 is provided on the upper surface of the die 1 and outside the discharge port 7. A heat insulating plate 24 is provided between the inner heating plate 22 and the upper surface of the die 1, and a heat insulating plate 25 is provided between the outer heating plate 23 and the upper surface of the die 1. There is. Further, a heater 26 is attached to the inner peripheral surface of the recess 21 of the inner heating plate 22, and the heater 26 has a through hole 44 formed in the mandrel 3, an air communication path 11, and an air ejection port 10. It is designed to be energized by the wiring 28 which is electrically connected to the inside. Through hole 44
The outer end of is closed by a blind plug 44a that prevents the air in the air passage 11 from leaking to the outside. Also,
A heater 27 is attached to the outer peripheral surface of the outer heating plate 23.

An annular cooling air supply device 13 is arranged above the die 1 to cool the resin 5 by ejecting cooling air to the outer periphery of the resin 5 which is cylindrically discharged from the discharge port 7. It is set up.

Next, the operation of this embodiment will be described.

When resin molding is performed in this embodiment, a predetermined resin 5 is melted by the extruder and supplied to the feed port 8 of the die 1. The molten resin 5 is supplied to the resin introducing passage 9 and the resin. The air is discharged from the discharge port 7 through the respective flow paths 6 into a cylindrical shape, air is sent from the air supply port 12, and the air is ejected from the air ejection port 10 through the air communication path 11 to eject the air. The resin 5 discharged from is blown up.

In this case, in the present embodiment, when the resin molding is performed, the heaters 26 and 27 are energized, and the inner heating plate 22 is energized by energizing the heaters 26 and 27. And the outer heating plate 23, respectively. The inner heating plate 22 and the outer heating plate 23 respectively heat the inner surface of the molten resin 5 passing from the discharge port 7 between the inner heating plate 22 and the outer heating plate 23, and The outer surface is heated instantaneously. As the heating temperature, for example, when the temperature of the molten resin 5 supplied from the extruder is about 200 to 220 ° C., each surface of the molten resin 5 is covered by the inner heating plate 22 and the outer heating plate 23. It is heated to about 250 ° C.

FIG. 2 shows the surface condition of the molten resin 5. When the molten resin 5 supplied from the extruder is discharged and molded as it is, the surface of the resin 5 is as shown in FIG. 2 (a). Since the irregularities are formed on the surface and irregular light is reflected from the outside, the transparency is deteriorated. However, as in this embodiment, the surface of the molten resin 5 supplied from the extruder at the temperature t _e is melted. When a predetermined temperature t _S is applied immediately before the ejection of the resin 5, the surface of the molten resin 5 is smoothed and ejected, as shown in FIG. 2B. As shown in FIG. 2 (c), since the surface is made smooth, light from the outside is not irregularly reflected and the transparency can be improved.

Thereafter, the resin 5 discharged from the discharge port 7 of the die 1 is cooled by the cooling air blown from the cooling air supply device 13 and pulled up by a pinch roller (not shown).

Therefore, in this embodiment, the die 1
Immediately before the molten resin 5 supplied to the discharge port 7 is discharged from the discharge port 7, the inner heating plate 22 and the outer heating plate 23 instantaneously heat and discharge the surface of the molten resin 5. It is possible to remove irregularities on the surface of the resin 5 and mold it smoothly, and as a result, the transparency of the molding resin 5 can be remarkably enhanced, and the quality of the molding resin 5 can be improved, and the resin 5 having an extremely high commercial value. Can be obtained.

FIG. 3 shows another embodiment of the present invention. In this embodiment, a flat heater 26 is arranged on the upper surface of the inner heating plate 22 and the outer heating plate 2 is provided.
The flat heater 27 is arranged on the upper surface of No. 3, and the other parts are the same as those in the above-mentioned embodiment, so that the same parts are designated by the same reference numerals and the description thereof is omitted. .

Also in this embodiment, as in the case of the above-described embodiment, when resin molding is performed, the heaters 26, 2 are
The inner surface and the outer surface of the molten resin 5 passing from the discharge port 7 between the inner heating plate 22 and the outer heating plate 23 by energizing 7 to heat the inner heating plate 22 and the outer heating plate 23, respectively. Is heated for a moment to make the surface of the molten resin 5 smooth, and the molten resin 5 is discharged.

Therefore, also in the present embodiment, it is possible to remove the irregularities on the surface of the ejection resin 5 and perform the molding smoothly, and as a result, the light from the outside is not irregularly reflected, and the molding resin 5 is prevented. The transparency can be significantly increased. Moreover, since the inner heating plate 22 and the outer heating plate 23 are heated by the flat heaters 26 and 27, respectively, the heating efficiency can be improved.

FIG. 4 shows another embodiment of the present invention. In this embodiment, the upper surfaces of the inner heating plate 22 and the outer heating plate 23 are the same as those of the embodiment shown in FIG. The flat heaters 26 and 27 are arranged on the outer heating plate 2 on the upper surface of the main body 4.
An annular void 29 is formed at a position corresponding to the lower surface of the heat insulating plate 25 of No. 3. In addition, an air escape hole 30 is formed in the main body 4 and communicates with the gap 29 and opens on a side surface of the main body 4. Since other parts are the same as those in the above-mentioned embodiment, the same parts are designated by the same reference numerals and the description thereof will be omitted.

Also in this embodiment, as in the case of the above-mentioned embodiment, when the resin is molded, the heaters 26 and 27 are energized to heat the inner heating plate 22 and the outer heating plate 23, respectively. The surface of the molten resin 5 is heated so that the surface of the molten resin 5 is smoothed and discharged. In this case, in this embodiment, since the air escape hole 30 is formed, the outer heating plate 23 is replaced by the heater 27.
When heated by, the heat transferred to the heat insulating plate 25 can be released to the outside through the air escape hole 30, and the heat radiating effect of the heat insulating plate 25 can be enhanced.

Therefore, also in the present embodiment, it is possible to remove the irregularities on the surface of the ejection resin 5 and perform the molding smoothly, and as a result, the light from the outside is not irregularly reflected, and the molding resin 5 is prevented. The transparency can be significantly increased.

FIG. 5 shows still another embodiment of the present invention. In this embodiment as well, like the embodiment shown in FIG. 4, the outer heating plate is the upper surface of the main body 4. Two
An annular gap 29 is formed on the lower surface side of the heat insulating plate 25 of No. 3, and in this embodiment, on the lower surface side of the heat insulating plate 24 of the inner heating plate 22 which is the upper surface of the mandrel 3. An annular space 31 is formed.

Further, in this embodiment, the outer heat exchanger 32 and the inner heat exchanger 33 are provided, respectively, and the outer heat exchanger 32 and the inner heat exchanger 3 are provided.
A circulation pipe 35 through which a predetermined refrigerant is circulated via valves 34, 34 is disposed in the valve 3. Further, in the outer heat exchanger 32, a medium supply pipe 36 for exchanging heat with a refrigerant circulated in the circulation pipe 35 for sending a predetermined temperature control medium to the outer heat exchanger 32 and sending it to the gap 29 of the main body 4. Also, a medium recovery pipe 37 for recovering the temperature control medium supplied to the space 29 to the outer heat exchanger 32 is provided, and the outer heat exchanger 32 has a space 29 portion of the main body 4. A temperature controller 39 for adjusting the temperature of the temperature adjusting medium based on the detected temperature sent from the temperature sensor 38 disposed in the above through the cable 38a is attached. Further, similarly, in the inside heat exchanger 33, a predetermined temperature control medium is caused to exchange heat with the refrigerant circulated in the circulation pipe 35, and the inside heat exchanger 33 receives air from the lower end surface of the mandrel 3. Supply port 12 to 90
A medium supply pipe 40 that penetrates inward through a through hole 45 formed at a position displaced in the circumferential direction and is sent to the space 31 of the mandrel 3 through the air passage 11 and a temperature control medium supplied to this space 31. Medium recovery pipes 41 for recovery are respectively arranged in the inside heat exchanger 33, and the inside heat exchanger 33 is passed through a cable 42a from a temperature sensor 42 arranged in the space 31 of the mandrel 3. A temperature controller 43 for adjusting the temperature of the temperature control medium based on the detected temperature sent is attached.
The outer end of the through hole 45 is closed by a blind plug 44a that prevents the air in the air passage 11 from leaking to the outside.

Also in this embodiment, as in the case of the previous embodiment, the heaters 26 and 27 are energized to supply power to the inner heating plate 2.
By heating each of the outer heating plate 2 and the outer heating plate 23, the surface of the discharge resin 5 is heated and the surface of the molten resin 5 is smoothed and discharged.

In this case, in this embodiment, a predetermined refrigerant is circulated in the outer heat exchanger 32 and the inner heat exchanger 33 by the circulation pipe 35, and this refrigerant and a predetermined temperature control medium are supplied. By exchanging heat, the temperature adjusting medium is brought to a predetermined temperature and the temperature adjusting medium is supplied to the space 29 of the main body 4 and the space 31 of the mandrel 3 through the medium supply pipes 36 and 40. Then, this temperature control medium exchanges heat with the heat insulating plates 24 and 25 to cool the heat insulating plates 24 and 25, and thereafter, the medium recovery pipe 37,
It is returned to the outer heat exchanger 32 and the inner heat exchanger 33 via 41. At this time, in this embodiment, the temperature sensors 38 and 42 detect the temperature of the temperature control medium supplied to the gaps 29 and 31, and the temperature controllers 39 and 43 are operated based on the detected temperatures. The temperature of the temperature adjusting medium in each of the heat exchangers 32 and 33 is adjusted.

Therefore, also in the present embodiment, it is possible to remove the irregularities on the surface of the ejection resin 5 and perform the molding smoothly, and as a result, the light from the outside is not irregularly reflected, and the molding resin 5 is prevented. The transparency can be significantly increased. Moreover, since the temperature adjusting medium whose temperature is adjusted by the heat exchangers 32 and 33 is supplied to the gaps 29 and 31 of the main body 4 and the mandrel 3, the temperatures of the heat insulating plates 24 and 25 are properly controlled. can do.

In this embodiment, the temperature of the heat insulating plates 24 and 25 is controlled by using the temperature adjusting medium adjusted to a predetermined temperature by the heat exchanger. However, for example, the heaters 26 and 27 are used. Alternatively, a temperature control medium may be used. In this case, the heat exchanger may be adjusted to raise the temperature of the temperature control medium.

Further, the present invention is not limited to the above-mentioned embodiment, but various modifications can be made if necessary.

[0040]

As described above, in the extrusion molding apparatus according to the present invention, the surface of the molten resin is instantaneously moved by the inner heating plate and the outer heating plate immediately before the molten resin supplied to the die is discharged from the discharge port. Since it was heated so that it was ejected,
It is possible to remove irregularities on the surface of the discharged resin and perform smooth molding, and as a result, the transparency of the molding resin can be remarkably increased, and the quality of the molding resin can be improved to obtain a resin having an extremely high commercial value. There is an effect such as being able to.

[Brief description of drawings]

FIG. 1 is a vertical sectional view showing an embodiment of a die of an extrusion molding apparatus according to the present invention.

FIG. 2 (a) is an explanatory view showing a surface state of a resin which is naturally solidified, FIG. 2 (b) is an explanatory view showing a state in which a molten resin is heated, and FIG. 2 (c) is a state in which the molten resin is heated. Explanatory diagram showing the state where the surface has been smoothed

FIG. 3 is a vertical sectional view of a part of a die showing another embodiment of the present invention.

FIG. 4 is a vertical sectional view of a part of a die showing another embodiment of the present invention.

FIG. 5 is a longitudinal sectional view of a die showing another embodiment of the present invention.

FIG. 6 is a schematic configuration diagram showing a conventional extrusion molding apparatus.

FIG. 7 is an explanatory view showing a conventional means for increasing the transparency of resin.

FIG. 8 is an explanatory view showing another means for improving the transparency of a conventional resin.

[Explanation of symbols]

1 die 3 Mandrel 4 body 5 resin 7 outlet 10 Air jet 22 Inner heating plate 23 Outside heating plate 24,25 heat insulation board 26,27 heater 29,31 void 30 Air escape hole 32 Outside heat exchanger 33 Inside heat exchanger 35 Circulation piping 36,40 medium supply piping 37,41 Media recovery piping 38,42 Temperature sensor 39,43 Temperature controller

Claims (5)

(57) [Claims] 1. An extruder for melting and extruding a predetermined resin is provided, and a die having a discharge port for molding and discharging the molten resin into a cylindrical shape is connected to the extruder, and a central portion of the die is connected. In an extrusion molding apparatus in which air is ejected to the inside of the resin discharged from the discharge port to blow and expand the resin, an extrusion molding device is provided on the upper surface of the die and inside the discharge port. with arranging the inner heating plate forming the inner peripheral surface of the discharge port formed in an annular shape so as not to block the air ejection port, which is formed annularly on the outside of the discharge port on the upper surface of the die ejection An extrusion molding apparatus, wherein an outer heating plate forming an outer peripheral surface of an outlet is provided, and heaters are attached to the inner heating plate and the outer heating plate. 2. The extrusion molding apparatus according to claim 1, wherein a heat insulating plate is provided between the inner heating plate and the outer heating plate and the upper surface of the die. 3. The extrusion molding apparatus according to claim 2, wherein the die is formed with an air escape hole that communicates the heat insulating plate portion of the outer heating plate with the outside. 4. A heat exchanger for exchanging heat with a temperature control medium by a predetermined refrigerant is provided, and a medium pipe for circulating the temperature control medium from the heat exchanger to each of the heat insulating plate portions is provided. The extrusion molding apparatus according to claim 2. 5. A temperature sensor is provided on each of the heat insulating plate portions, and a temperature controller for adjusting the temperature of the temperature adjusting medium based on the temperature detected by the temperature sensor is provided on the heat exchanger. The extrusion molding apparatus according to claim 1, wherein: