JPH081754A - Screw conveyor for extruder - Google Patents

Abstract

PURPOSE:To provide an extruder wherein air mixed in a cylinder can be appropriately discharged outside, a molten resin in which air is not mixed can be appropriately fed to a head, and quality of the molded resin can be raised. CONSTITUTION:A screw conveyor 6 wherein a helical screw vane 7 carrying a resin fed from a hopper toward an extrusion opening is formed is, in a freely rotatively drivable manner, arranged inside a cylindrical cylinder. A deaerating groove 23 is formed on an outer peripheral surface of the screw vane 7 of the screw conveyor 6 so that a micro-gap is provided between an outer peripheral surface on a base end side of the screw conveyor 6 and an inner peripheral face of the cylinder.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a screw conveyor of an extruder, and more particularly, to a die of an extrusion molding apparatus for molding a film or the like having a predetermined shape in a cylinder in which resin fed from a hopper of the extruder is sealed. The present invention relates to a screw conveyer of an extruder for melting and conveying.

[0002]

2. Description of the Related Art Generally, for example, in an extrusion molding apparatus for molding a desired tubular film by discharging a molten resin into a tubular shape from a discharge port of a die, a resin such as a thermoplastic resin fed from a hopper is sealed. An extruder is used for melting and feeding to the die while being transported by a screw conveyor in a cylinder.

FIG. 9 shows such a conventional extruder. The extruder 1 has a cylindrical cylinder 2, and a predetermined upper surface of the cylinder 2 on the base end side. A hopper 4 for supplying the resin 3 into the cylinder 2 is attached. Further, inside the cylinder 2, there is disposed a screw conveyor 6 that conveys the resin 3 supplied from the hopper 4 toward an extrusion port 5 formed at the tip of the cylinder 2. On the outer peripheral surface of the conveyor 6, screw blades 7 formed in a spiral shape are projected. The screw conveyor 6 is composed of a supply area having a small root diameter, a compression area having a gradually increasing diameter, and a feeding area having a large diameter.

A speed reducer 8 is attached to the base end of the cylinder 2, and an output shaft 9 connected to the base end of the screw conveyor 6 is provided inside the speed reducer 8. It is rotatably supported by a thrust bearing 10 that supports in the axial direction and a bearing 11 that supports the peripheral surface. Further, a drive gear 12 connected to a drive source such as a drive motor (not shown) is attached to a midway portion of the output shaft 9, and the drive gear 12 is rotationally driven by the drive source to output the output shaft 9. The screw conveyor 6 is rotationally driven at a predetermined speed via 9

A cooling jacket 13 is mounted on the outer periphery of the mounting portion of the hopper 4 of the cylinder 2, and the cooling jacket 13 is supplied with water for supplying cooling water to the inside of the cooling jacket 13. A drain pipe 15 for discharging the cooling water inside the pipe 14 and the cooling jacket 13 is connected thereto. Further, a plurality of band-shaped heaters 16 for melting the resin 3 supplied from the hopper 4 to the inside of the cylinder 2 are mounted on the outer peripheral surface of the cylinder 2, and the outer periphery of the middle portion of the cylinder 2 is mounted. Is provided with a plurality of thermocouple sensors 17 for measuring the temperature of the molten resin 3 inside the cylinder 2.

Further, the extrusion port 5 of the cylinder 2 has a
A head 18 for feeding the molten resin 3 extruded from the cylinder 2 upward is attached, and the head 18 is provided with a ring-shaped discharge port 20 at an upper part through a joint 19 for forming a tubular film. Die 21 is detachably connected.

In the conventional extruder 1, the predetermined resin 3 introduced into the supply area of the cylinder 2 from the hopper 4 of the extruder 1 is conveyed by the screw conveyor 6 and is heated by the heater 16 in the compression area. The molten resin 3 is heated and melted and compressed, and the molten resin 3 is held at a predetermined stretching temperature in the feeding area, extruded from the head 18, and subsequently sent to the die 21. And this die 21
To form the molten resin 3 into a tubular shape to form the discharge port 2
By ejecting upward from 0, for example, a cylindrical tubular film is molded.

However, in such a conventional extruder 1, since the resin 3 is usually in the form of particles or powder, when the resin 3 is supplied from the hopper 4, the particles of the resin 3 as well as the external air are also supplied. Will be supplied to the inside of the cylinder 2. When the resin 3 and the air are heated by the heater 16 inside the cylinder 2 as described above, the air is mixed into the resin 3 and exists as bubbles inside the resin 3. In some cases, heating the resin 3 may generate gas from the resin 3 itself.

When the bubbles are mixed in the molten resin 3 in this way, the strength of the resin 3 is locally reduced, and when the bubbles are present on the surface of the resin 3, the molding resin 3 is formed.
When the above tubular film is molded, pinholes are generated in the molding resin 3 due to the bubbles, and in some cases, the film has holes or is damaged. Therefore, there is a problem that molding defects and molding failure occur.

Further, when the gas inside the cylinder 2 further expands due to the heating of the heater 16, the gas has compressibility, so that when passing through the complicated resin 3 passage inside the cylinder 2 and inside the head 18. However, various volume changes and pressure changes may occur, and extrusion pulsation may occur. Furthermore, there is a problem that the molten resin 3 is oxidized by being in contact with the air inside the cylinder 2, and the quality of the resin 3 is deteriorated, resulting in deterioration of the quality of the resin product.

Further, the internal pressure of the cylinder 2 is 500
Since the pressure is as high as kg / cm 2 or more, there is a problem that the resin 3 may be burnt black due to local explosion due to oxidation of the resin 3 by air.

In order to solve such a problem, conventionally, as shown in FIG. 10, a deaeration window 22 for discharging the air mixed in the cylinder 2 to the outside is formed in the middle of the cylinder 2. The extruder 1 configured to do so is used.

[0013]

However, in the conventional extruder 1, when the supply amount of the resin 3 is increased in order to increase the production amount, the internal pressure of the cylinder 2 increases, so that the molten resin 3 is generated. The cylinder 2 overflows from the deaeration window 22 to cause waste of the resin 3, and there is a problem that the high temperature molten resin 3 is extremely dangerous for the operator. On the other hand, if the supply amount of the resin 3 is reduced to reduce the production amount, a space is created between the screw grooves of the screw conveyor 6, so that the degassing window 2
There is also a problem that air is sucked in reverse from 2 and more air is mixed in the molten resin 3.

Further, the molten resin 3 is removed from the degassing window 22.
If it adheres to the periphery of this, the resin 3 will be burnt while growing due to the heat of the heater 16, and finally the burned resin 3 will reach the screw blades 7 of the screw conveyor 6 and enter the inside of the cylinder 2. There is a problem in that, when the resin 3 that has entered and is fed together with the molten resin 3 is molded, and this scorched resin 3 is molded, it causes pinholes, resulting in deterioration of the quality of the molded resin 3.

The present invention has been made in view of these points, and it is possible to properly discharge the air mixed in the cylinder to the outside, and to appropriately feed the molten resin containing no air to the head. It is an object of the present invention to provide a screw conveyor of an extruder that can improve the quality of molding resin.

[0016]

In order to achieve the above-mentioned object, the screw conveyor of the extruder according to the invention described in claim 1 supplies a predetermined resin to the base end of a cylindrical cylinder inside the cylinder. With a hopper for
Inside the extruder having a heater for heating and melting the resin on the outer peripheral surface of the cylinder, a spiral screw blade is formed on the outer periphery, and the resin supplied from the hopper to the inside of the cylinder by rotation is In a screw conveyor of an extruder for transporting toward the extrusion port at the tip of the cylinder, a deaeration groove is formed on the outer peripheral surface of the screw blade of the screw conveyor.

In the invention according to claim 2, a degassing passage extending in the axial direction and opening at the base end face is formed in the central portion of the screw conveyor, and the screw conveyor is provided at the bottom of the degassing groove. A plurality of deaeration holes penetrating in the radial direction and communicating with the deaeration passage are provided so as to have a predetermined interval in the circumferential direction.

Further, preferably, the outer diameter of the base end of the screw conveyor from the deaeration groove of the screw blade is formed to be slightly smaller than the outer diameter of the tip end of the screw conveyor, and the outer diameter of the screw blade is removed. It is characterized in that a minute gap is formed between the outer peripheral surface of the screw conveyor from the air groove and the inner peripheral surface of the cylinder, and the base end of the screw conveyor from the degassing groove of the screw blade. It is characterized in that a plurality of deaeration slits having a minute width dimension are formed on the side outer circumference so as to have predetermined intervals in the circumferential direction. Further, preferably, a plurality of deaeration holes having a minute diameter are formed at a predetermined interval in the circumferential direction on the base end side of the screw conveyor from the deaeration groove of the screw blade. In addition, an air discharge device is connected to the degassing passage of the screw conveyor.

Further, in the screw conveyor of the extruder according to the invention described in claim 7, a hopper for supplying a predetermined resin into the inside of the cylinder is provided at the base end of the cylinder. A screw formed with an extrusion port for extruding a molten resin at the tip of the cylinder, and a spiral screw blade for conveying the resin supplied from the hopper toward the extrusion port inside the cylinder. In a screw conveyor of an extruder in which a conveyor is rotatably arranged and a heater for heating and melting the resin is arranged on the outer peripheral surface of the cylinder, a base extending in the axial direction at the center of the screw conveyor. Forming a degassing passage opening to the end face,
A plurality of deaeration holes that penetrate the screw conveyor in the radial direction and are in communication with the deaeration passage in the outer peripheral surface of the screw conveyor near the base end side of the screw conveyor of the screw blades have a predetermined interval in the circumferential direction. It is characterized by being drilled in.

Further, in the screw conveyor of the extruder according to the invention described in claim 8, a hopper for supplying a predetermined resin to the inside of the cylinder is provided at the base end of the cylinder. A screw formed with an extrusion port for extruding a molten resin at the tip of the cylinder, and a spiral screw blade for conveying the resin supplied from the hopper toward the extrusion port inside the cylinder. In a screw conveyor of an extruder in which a conveyor is rotatably arranged and a heater for heating and melting the resin is arranged on the outer peripheral surface of the cylinder, a base extending in the axial direction at the center of the screw conveyor. A deaeration passage opening to the end face is formed, and a plurality of deaeration holes, which penetrate the screw conveyor in the radial direction and communicate with the deaeration passage, are formed on the outer peripheral surface of the screw blade in the circumferential direction. Is characterized in that the bored to have a septum.

[0021]

According to the screw conveyor of the extruder according to the first aspect of the present invention, the resin is supplied from the hopper to the inside of the cylinder while the screw conveyor is rotationally driven, and the resin is screwed by the screw conveyor. The resin is melted by operating the heater while being conveyed to the extrusion port of the conveyor, and the molten resin is sent from the extrusion port to a predetermined resin molding die. When the resin is fed by the screw blades of the screw conveyor, the air mixed with the resin from the hopper into the cylinder is expelled from the resin by the pressing force of the screw blades, and the screw conveyor of the screw blades. Is collected in the vicinity of the side surface on the base end side of the air, and the air is a minute gap formed between the outer peripheral surface of the screw blade and the inner peripheral surface of the cylinder.
The gas flows into the degassing groove through the degassing slit or the degassing hole and is discharged to the outside through the hopper.
Further, according to the screw conveyor of the extruder according to claim 2, the air flowing into the degassing groove is sent to the degassing passage through the degassing hole and is discharged to the outside. If the air inside the deaeration passage is sucked by using the exhaust device, the internal pressure of the deaeration passage becomes low, and the air flowing into the deaeration groove is smoothly introduced into the deaeration passage through the deaeration hole. Can be sent.

According to the screw conveyor of the extruder of claim 7, the air expelled from the resin is
The air will be concentrated in the vicinity of the base end side of the screw conveyor of the screw blades, and this air can be sent to the deaeration passage through the deaeration hole and discharged to the outside. Further, according to the screw conveyor of the extruder according to claim 8, the air expelled from the resin passes through the gap between the outer peripheral surface of the screw blade and the inner peripheral surface of the cylinder and flows into the deaeration hole. It can be released to the outside through the degassing passage.

[0023]

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

FIG. 1 shows an embodiment of a screw conveyor applied to the screw conveyor of an extruder according to the present invention. The outer peripheral surface of a screw conveyor 6 rotatably arranged inside a cylinder (not shown). A screw blade 7 formed in a spiral shape is provided so as to protrude from the inner surface of the screw blade 7. In this embodiment, a degassing groove 23 is formed on the outer peripheral surface of the screw blade 7. The deaeration groove 23 may be formed at least on the tip side of the compression region where the root diameter is gradually increased to the larger diameter, but may be formed over the entire area of the screw blade 7 of the screw conveyor 6. In addition, the screw blade 7
The outer diameter of the screw conveyor 6 from the deaeration groove 23 is
The diameter is slightly smaller than the outer diameter on the tip side of the screw conveyor 6, and a minute gap is formed between the outer peripheral surface on the base end side of the screw conveyor 6 and the inner peripheral surface of the cylinder by the deaeration groove 23 of the screw blade 7. It is designed to be done.

Next, the operation of this embodiment will be described.

In the present embodiment, the screw conveyor 6
By supplying a resin (not shown) from the hopper (not shown) to the inside of the cylinder by rotating the resin, and by operating the heater while conveying the resin to the tip side of the screw conveyor 6 by the screw conveyor 6, Is melted, and this molten resin is sent to a predetermined resin molding die through a head (not shown).

When the resin is fed by the screw blades 7 of the screw conveyor 6, the molten resin moves between the screw blades 7. During the movement, the molten resin is The side surface of the screw blade 7 on the tip side of the screw conveyor 6, that is, the left side surface of the screw blade 7 in FIG. In this case, the air mixed in the cylinder together with the resin from the hopper is expelled from the resin by the pressing force of the screw blade 7, and the vicinity of the side surface of the screw blade 7 on the base end side of the screw conveyor 6, that is, in FIG. They will gather near the right side of the screw blade 7. This air passes through the deaeration groove 2 of the screw blade 7 through a minute gap formed between the outer peripheral surface of the screw conveyor 6 on the base end side and the inner peripheral surface of the cylinder.
3 and is discharged from the hopper to the outside.

At this time, since the size of the gap between the screw blade 7 and the inner peripheral surface of the cylinder is extremely small, the molten resin having high viscous resistance will not flow into the deaeration groove 23 through the minute gap. Absent.

Therefore, in this embodiment, the air mixed in the cylinder can be surely discharged to the outside through the deaeration groove 23, so that the molten resin containing no bubbles is fed to the head. As a result, it is possible to prevent a local decrease in the strength of the molding resin due to the inclusion of air bubbles, prevent damage to the molding resin due to the occurrence of pinholes, and perform proper molding. Further, since extrusion pulsation due to expansion of bubbles does not occur, molten resin can be smoothly fed, and since molten resin is not exposed to the outside air, oxidation of molten resin inside the cylinder is reliably prevented. It is possible to prevent deterioration of resin quality and improve the quality of resin products.

Further, since the deaeration window is not formed in the cylinder as in the conventional case, the molten resin does not leak to the outside of the cylinder, and furthermore, the air may be sucked into the cylinder. Absent. Further, it is possible to reliably prevent the occurrence of charring due to the molten resin adhering to the deaeration window.

FIG. 2 shows another embodiment of the present invention, in which a degassing groove 23 is formed on the outer peripheral surface of the screw blade 7 formed on the outer peripheral surface of the screw conveyor 6. Also in this embodiment, the outer diameter of the screw conveyor 6 on the base end side is slightly smaller than the outer diameter of the screw conveyor 6 on the front end side, as in the above embodiment.

Further, in the present embodiment, a degassing passage 24 extending in the axial direction and opening at the base end face is formed at the center of the screw conveyor 6, and at the bottom of the degassing groove 23. , A plurality of deaeration holes 25, 25 penetrating the screw conveyor 6 in the radial direction and communicating with the deaeration passage 24.
Are formed so as to have a predetermined interval in the circumferential direction. Further, an air discharge device 26 such as a vacuum pump is connected to the degassing passage 24.

Next, the operation of this embodiment will be described.

In the present embodiment, when the resin is fed by the screw blades 7 of the screw conveyor 6, the air expelled from the resin by the pressing force of the screw blades 7 is the degassing groove of the screw blades 7. 23, is sent to the degassing passage 24 through the degassing hole 25, and is discharged to the outside by the air discharging device 26. At this time, in the present embodiment, since the air exhaust device 26 sucks the air inside the deaeration passage 24, the internal pressure of the deaeration passage 24 becomes low and the air flowing into the deaeration groove 23 is removed. It can be smoothly sent to the degassing passage 24 through the degassing hole 25. Also,
Since the gap between the screw blade 7 and the inner peripheral surface of the cylinder is extremely small, the molten resin does not flow into the degassing groove 23.

Therefore, also in this embodiment, as in the previous embodiment, the air mixed in the cylinder is degassed by the degassing groove 2.
3, the degassing hole 25 and the degassing passage 24 can be surely discharged to the outside, so that the molten resin without inclusion of bubbles can be fed to the head, and as a result, the molding resin is damaged. Can be prevented and proper molding can be performed. Further, the molten resin can be smoothly fed, and further, the oxidation of the molten resin inside the cylinder can be prevented and the quality of the resin product can be improved. Further, the molten resin does not leak to the outside of the cylinder, and furthermore, the air is not sucked into the inside of the cylinder.

Further, FIGS. 3 and 4 show another embodiment of the present invention, in which a degassing groove 23 is formed on the outer peripheral surface of the screw blade 7 of the screw conveyor 6, and this degassing is performed. As shown in FIG. 4, a plurality of degassing slits 27, 27 ... Having a minute width dimension are arranged at predetermined intervals in the circumferential direction on the outer periphery of the screw blade 7 on the base end side of the screw conveyor 6 with respect to the groove 23. Is formed in.

Since the other structure is the same as that of the above-mentioned embodiment, the same parts are designated by the same reference numerals and the description thereof will be omitted.

In this embodiment, when the resin is fed by the screw blades 7 of the screw conveyor 6, the air expelled from the resin by the pressing force of the screw blades 7 is used for degassing the screw blades 7. It flows into the degassing groove 23 through the slit 27, is sent to the degassing passage 24 through the degassing hole 25, and is discharged to the outside by the air discharging device. At this time, since the width dimension of the degassing slit 27 is extremely small, the molten resin having high viscous resistance is
It does not flow into the degassing groove 23 from the minute gap.

Therefore, also in this embodiment, as in the previous embodiment, the air mixed in the cylinder is degassed by the slit 27 for degassing, the degassing groove 23, the degassing hole 25 and the degassing passage 2.
Since it can be surely discharged to the outside through each of 4, it is possible to feed the molten resin containing no air bubbles to the head, and as a result, it is possible to prevent the molding resin from being damaged and perform proper molding. be able to. Further, the molten resin can be smoothly fed, and further, the oxidation of the molten resin inside the cylinder can be prevented and the quality of the resin product can be improved. Further, the molten resin does not leak to the outside of the cylinder, and furthermore, the air is not sucked into the inside of the cylinder.

In the above embodiment, the deaeration slit 2 is used to allow the air in the cylinder to flow into the deaeration groove 23.
However, as shown in FIG. 5, a plurality of deaeration holes 28 having a minute diameter may be formed.

FIG. 6 shows another embodiment of the present invention. In this embodiment, two degassing grooves 23a, 23 are provided on the outer peripheral surface of the screw blade 7 of the screw conveyor 6.
b are formed in parallel, and these deaeration grooves 23a, 23
A plurality of degassing slits 27 having a minute width dimension are formed at predetermined intervals in the circumferential direction on each outer circumference of the screw blade 7 on the base end side of the screw conveyor 6 with respect to b. In addition, the deaeration groove 23a on the tip side of the screw conveyor 6
A plurality of deaeration holes 25 communicating with a deaeration passage 24 formed at the center of the screw conveyor 6 are formed in the.

Since other structures are the same as those shown 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, when the resin is fed by the screw blades 7 of the screw conveyor 6, the air expelled from the resin by the pressing force of the screw blades 7 is degassed by each of the screw blades 7. It flows into the degassing grooves 23a and 23b through the slit 27, is sent to the degassing passage 24 through the degassing hole 25, and is discharged to the outside by the air discharging device. At this time, since the width dimension of the deaeration slit 27 is extremely small, the molten resin having high viscous resistance does not flow into the deaeration grooves 23a and 23b from the minute gap. Moreover, in this embodiment, since the two degassing grooves 23a and 23b are formed, the molten resin should flow from the degassing slit 27 into the degassing groove 23b on the base end side of the screw conveyor 6. Even in the case, the degassing groove 23a on the tip side of the screw conveyor 6 does not flow into the degassing groove 23a on the tip side.
The air can be properly discharged.

Therefore, also in this embodiment, as in the previous embodiment, the air mixed in the cylinder is passed through the deaeration slit 27, the deaeration grooves 23a and 23b, the deaeration hole 25 and the deaeration passage 24, respectively. Since it is possible to reliably discharge the resin to the outside, it is possible to feed the molten resin containing no air bubbles to the head, and as a result, it is possible to prevent damage to the molding resin and perform proper molding. Furthermore, the molten resin can be smoothly fed, and moreover,
Oxidation of the molten resin inside the cylinder can be prevented to improve the quality of the resin product. Further, the molten resin does not leak to the outside of the cylinder, and furthermore, the air is not sucked into the inside of the cylinder.

FIG. 7 shows still another embodiment of the present invention. In this embodiment, the degassing groove is not formed, and the outer peripheral surface of the root diameter of the screw conveyor 6 is In the vicinity of the base end side of the screw conveyor 6 of 7,
A plurality of deaeration holes 25, 25 ... Having a small diameter, which communicate with a deaeration passage 24 formed at the center of the screw conveyor 6, are formed.

In the present embodiment, when the resin is fed by the screw blades 7 of the screw conveyor 6, the air expelled from the resin by the pressing force of the screw blades 7 is the screw conveyor 6 of the screw blades 7. The air will be concentrated in the vicinity of the base end side, and this air will be sent to the degassing passage 24 through the degassing hole 25 and will be discharged to the outside by the air discharging device. At this time, the molten resin is pressed by the screw blades 7 and collected on the tip side of the screw conveyor 6 of the screw blades 7. The air expelled from the resin by the pressing force of the screw blades 7 is The remaining volume between the two is gathered in the vicinity of the base end side surface of the screw conveyor 6 of the screw blades 7. Further, in this embodiment, since the degassing holes 25 are formed in the portions where the air gathers, a large amount of extruding amount required to fill the molten resin between the screw blades 7 is not required. In this state, the molten resin does not flow into the degassing holes 25.

Therefore, also in this embodiment, as in the previous embodiment, the air mixed in the cylinder is degassed by the degassing holes 2.
5 can be surely discharged to the outside through the degassing passage 24 and the degassing passage 24, so that the molten resin without bubbles can be smoothly fed to the head, and as a result, proper resin molding can be performed. You can Further, the quality of the resin product can be improved by preventing the molten resin from oxidizing inside the cylinder, and the molten resin does not leak to the outside of the cylinder or suck air into the cylinder. Further, in this embodiment, since the deaeration groove is not formed, the structure is simple, and the manufacturing can be performed easily and at low cost.

FIG. 8 shows another embodiment of the present invention. In this embodiment, a plurality of deaeration holes communicating with the deaeration passage 24 are formed on the outer peripheral surface of the screw blade 7 of the screw conveyor 6. 25 is formed. In this case, the size of the gap between the outer peripheral surface of the screw blade 7 and the inner peripheral surface of the cylinder (not shown) is set to an appropriate size so that the molten resin having high viscosity does not pass but only the air passes.

Also in this embodiment, as in each of the above-mentioned embodiments, the air expelled from the resin by the pressing force of the screw blade 7 is generated between the outer peripheral surface of the screw blade 7 and the inner peripheral surface of the cylinder. It passes through the gap, flows into the degassing hole 25, and is discharged to the outside by the air discharge device 26 via the degassing passage 24. At this time, since the size of the gap between the screw blade 7 and the cylinder is extremely small, the molten resin having high viscous resistance does not flow into the degassing hole 25.

Therefore, in this embodiment as well, as in each of the above-described embodiments, the air mixed in the cylinder can be reliably discharged to the outside through the deaeration hole 25 and the deaeration passage 24, respectively, so that air bubbles are generated. It is possible to smoothly feed molten resin to the head, which results in
Appropriate resin molding can be performed. Further, the quality of the resin product can be improved by preventing the molten resin from oxidizing inside the cylinder, and the molten resin does not leak to the outside of the cylinder or suck air into the cylinder. Further, in this embodiment, since the deaeration groove is not formed, the structure is simple, and the manufacturing can be performed easily and at low cost.

The present invention is not limited to the above embodiment, but various modifications can be made as necessary.

[0052]

As described above, in the screw conveyor of the extruder according to the present invention, the air mixed in the cylinder can be surely discharged to the outside, so that the molten resin containing no air bubbles in the head can be discharged to the head. As a result, it is possible to prevent a local decrease in the strength of the molding resin due to the inclusion of air bubbles, prevent damage to the molding resin due to pinholes, etc., and perform proper molding. . further,
Since extrusion pulsation due to expansion of bubbles does not occur, the molten resin can be smoothly fed, and since the molten resin is not exposed to the outside air, it is possible to reliably prevent oxidation of the molten resin inside the cylinder. It is possible to prevent deterioration of resin quality and improve the quality of resin products. Moreover, since the deaeration window is not formed in the cylinder as in the conventional case, the molten resin does not leak to the outside of the cylinder, and furthermore, the air is not sucked into the cylinder. Further, it is possible to reliably prevent the occurrence of charring due to the molten resin adhering to the deaeration window.

[Brief description of drawings]

FIG. 1 is a schematic configuration diagram of a screw conveyor portion showing an embodiment of a screw conveyor of an extruder according to the present invention.

FIG. 2 is a schematic configuration diagram of a screw conveyor portion showing another embodiment of the present invention.

FIG. 3 is a schematic configuration diagram of a screw conveyor portion showing another embodiment of the present invention.

FIG. 4 is a sectional view of FIG.

FIG. 5 is a sectional view of a screw conveyor portion showing another embodiment of the present invention.

FIG. 6 is a schematic configuration diagram of a screw conveyor portion showing another embodiment of the present invention.

FIG. 7 is a schematic configuration diagram of a screw conveyor portion showing another embodiment of the present invention.

FIG. 8 is a schematic configuration diagram of a screw conveyor portion showing another embodiment of the present invention.

FIG. 9 is a schematic configuration diagram showing a conventional extruder.

FIG. 10 is a schematic configuration diagram showing another conventional extruder.

[Explanation of symbols]

 6 Screw Conveyor 7 Screw Blade 23 Degassing Groove 24 Degassing Passage 25 Degassing Hole 26 Air Discharge Device 27 Degassing Slit 28 Degassing Hole

Claims (8)

[Claims] 1. A hopper for supplying a predetermined resin to the inside of the cylinder is provided at the base end of a cylindrical cylinder, and a heater for heating and melting the resin is provided on the outer peripheral surface of the cylinder. An extruder for transporting the resin supplied from the hopper to the inside of the cylinder by rotation toward the extrusion port at the tip of the cylinder by forming a spiral screw blade on the outer periphery inside the extruder. The screw conveyor of the extruder, wherein degassing grooves are formed on the outer peripheral surface of the screw blades of the screw conveyor. 2. A degassing passage that extends in the axial direction and opens at the base end face is formed at the center of the screw conveyor, and the degassing is performed by radially passing through the screw conveyor at the bottom of the degassing groove. The screw conveyer for an extruder according to claim 1, wherein a plurality of deaeration holes communicating with the passage are provided at predetermined intervals in the circumferential direction. 3. The outer diameter of the screw conveyor on the proximal end side is formed to be slightly smaller than the outer diameter of the screw conveyor on the front end side of the deaeration groove of the screw blade. The screw conveyor of the extruder according to claim 1 or 2, wherein a minute gap is formed between the outer peripheral surface of the screw conveyor on the proximal end side and the inner peripheral surface of the cylinder. 4. A plurality of degassing slits having a minute width dimension are formed at a predetermined interval in the circumferential direction on the outer periphery of the screw conveyor at the base end side of the degassing groove of the screw blade. The screw conveyor of the extruder according to claim 1 or 2. 5. A plurality of deaeration holes having a minute diameter are formed at a predetermined interval in the circumferential direction on the base end side of the screw conveyor from the deaeration groove of the screw blade. The screw conveyor of the extruder according to claim 1 or claim 2. 6. The screw conveyor of the extruder according to claim 1, further comprising an air discharge device connected to a deaeration passage of the screw conveyor. 7. A hopper for supplying a predetermined resin to the inside of the cylinder is provided at the base end of the cylindrical cylinder, and an extrusion port for extruding the molten resin is provided at the tip of the cylinder. A screw conveyor formed with a spiral screw blade that conveys the resin supplied from the hopper toward the extrusion port inside the cylinder is rotatably arranged, and is provided on the outer peripheral surface of the cylinder. In a screw conveyor of an extruder provided with a heater for heating and melting the resin, a degassing passage extending in the axial direction and opening at the base end face is formed in the central portion of the screw conveyor, and the outer periphery of the screw conveyor. A plurality of deaeration holes that penetrate the screw conveyor in the radial direction and communicate with the deaeration passage in the vicinity of the base end side of the screw conveyor of the screw blades with a predetermined interval in the circumferential direction. A screw conveyor for an extruder, which is characterized in that 8. A hopper for supplying a predetermined resin to the inside of the cylinder is provided at the base end of the cylindrical cylinder, and an extrusion port for extruding the molten resin is provided at the tip of the cylinder. A screw conveyor formed with a spiral screw blade that conveys the resin supplied from the hopper toward the extrusion port inside the cylinder is rotatably arranged, and is provided on the outer peripheral surface of the cylinder. In an extruder screw conveyor provided with a heater for heating and melting the resin, a degassing passage extending in the axial direction and opening at the base end face is formed in the central portion of the screw conveyor, and the outer periphery of the screw blade A screw controller for an extruder, characterized in that a plurality of deaeration holes, which penetrate the screw conveyor in a radial direction and communicate with the deaeration passages, are formed in the surface so as to have a predetermined interval in the circumferential direction. Bear.