JP2001058347A - Screw for resin extruder and resin extruder - Google Patents

Abstract

PROBLEM TO BE SOLVED: To reduce the power consumption due to transfer power and a heater by shortening the effective length of a screw while ensuring the conventional production quantity of a resin and to correspond to the production of a resin of every kind even by a single screw by enhancing the transfer efficiency, heat efficiency and kneading efficiency of a resin while shortening the time required in the color change of a resin or the like. SOLUTION: The ratio of the effective length L2 to diameter D of a flight part 3 is almost set to 7-14 deg. and the lead angle thereof is almost set to 7-21 deg.. By this constitution, the it becomes possible to shorten the effective length L2 of the screw and, since the feed speed of a resin is decreased even in the same number of rotations as the conventional one, the pressing time of the resin to the inner wall of a cylinder becomes long and, since the charged resin is sufficiently charged in the gaps between the pitches of the screw, heat efficiency is enhanced to improve kneading efficiency and a slip is reduced to enhance resin feed efficiency.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a screw for a resin extruder which is rotatably housed in a cylinder, melts, kneads, and extrudes a raw material resin fed from a hopper by rotation feed.

[0002]

2. Description of the Related Art FIG. 11 is a schematic view showing a whole of a conventionally known pellet manufacturing apparatus. This pellet manufacturing apparatus has an extruder having a raw material supply port 01, a gas vent port 02, a heater 03 and the like. A screw 06 rotated by a motor 05 is inserted into the cylinder 04 of
The raw resin charged into the cylinder 04 is a screw 0
6, the strand A melted by the heater 03 while being kneaded by the screw 06 and melted by the die head 07 at the tip of the extruder is extruded.

The strand A extruded from the die head 07 is drawn into the water tank 08 and cooled by water. When the strand A is drawn out of the water tank 08 and drained by an air suction type drainer (not shown), the strand cutting machine is used. To be cut into pellets.

[0004] A resin extruder screw 06 shown in FIG. 12 includes a shank portion 09 and a flight portion 010.
When the screw 06 of the flight section 010 is used for a low speed, the effective length L of the flight section 010
The ratio of the diameter D to 2 is usually about 30, but the ratio of the diameter D to the flight portion effective length L2 is 40 or more in the high-speed screw.

Therefore, for example, if the diameter is 100 mm, the effective length L2 of the flight portion is 4000 mm,
The total length is 5000 mm including the shank.

[0006]

The screw 06 shown in FIG. 12 has a ratio of effective length to diameter (hereinafter referred to as L / D).
30), with a diameter of 1
In the case of 00 mm, the pitch P of the screw 06 is 10
0 mm, and the total number of ridges of the screw lead portion 010a is 30 which is the same as the L / D ratio. Therefore, the lead angle α of the screw 06 is formed at 26.5 degrees.

For this reason, when the screw 06 rotates, a slip occurs at the time of feeding the resin, and the feeding amount of the resin becomes half of the pitch interval P in the case of the general resin at the vent portion V, and becomes about 1/3 in the case of the hard resin. There was a problem of lowering.

Here, the flight portion 01 of the screw 06
0 will be described in detail. In accordance with the resin feeding direction in the longitudinal direction of the screw 06, the biting portion region M1, the melting / kneading start region M2, the melting / kneading region M3, the gas venting region M4, the scorch occurrence region M5, and the extruding portion region M6 in this order from the shank portion 09 side. Is divided into

In the figure, a region H is a hopper portion into which the resin is charged. In the region S, the resin is not melted, so that no scorching or scorching occurs, but a slip phenomenon at the time of feeding occurs. The area K is an area where burning and burning occur. In most cases, burning and burning occur in this area K.

That is, the screw 06 has a structure in which the raw material resin including the hopper H is fed by the screw 06 for a long distance and then melted by the heater 03 for the first time. Therefore, the feed amount of the resin transferred by the screw 06 is reduced to １ ／ to ３ at the vent portion V.

Therefore, since the remaining 1/2 to 2/3 of the resin stagnates in this portion, this portion is heated and becomes an area where scorching occurs.

On the other hand, if the rotational speed of the screw 06 is increased in order to increase the resin feeding speed, the resin that comes into contact with the inner wall surface of the cylinder is excessively melted due to frictional heat or the like and deteriorates, and the resin that does not melt in the screw valley becomes insoluble. The remaining phenomenon occurs.

In addition, since the L / D ratio is 30 to 40, the effective length L2 of the screw of the flight section 010 becomes longer, and the total length including the length L1 of the shank section 09 becomes longer. Had.

Further, in recent years, since the production of resin tends to be many kinds and small lots, the range of use of thick and long screws is limited, so that thin and long screws are demanded.

However, since slip and other problems have not been solved, in the case of small-scale production, the diameter of the screw is reduced to about 50 mm to cope with it. ~ 400
rpm), and further lengthen the screw,
Some motors have an increased output of 50 Kw in the case of a motor having a diameter of 50 mm, but at present, there is no fundamental support for multi-product, small-lot production.

The present invention has been made in view of such a problem. By reducing the effective length of the screw while securing the conventional resin production, the transfer power and the power consumption by the heater are reduced. It is reduced, and the resin transfer efficiency, heat efficiency, and cross-linking efficiency are improved, so that a single screw can cope with the production of various resins, and shortens the time required for setup change in resin color change and the like. It is an object of the present invention to provide a screw for a resin extruder that can be used.

[0017]

The gist of the present invention to achieve the above-mentioned object lies in the following items. [1] Screws for resin extruders (1, 1A, 1B) rotatably accommodated in cylinders (100, 100A, 100B), melted, kneaded, and extruded by feeding a raw material resin fed from a hopper. In the resin extruder screw (1, 1A, 1B), the ratio of the effective length to the diameter is approximately 7 to 14, and the lead angle of the screw (1, 1A, 1B) is approximately 7 to 21 degrees. A screw (1, 1A, 1B) for a resin extruder, which is formed with an inclination.

[2] The screw (1, 1A, 1B)
The pitch interval of the screw (1, 1A, 1B) of the resin extruder according to [1], wherein the pitch interval of the screw (1, 1A, 1B) is 1/4 to 3/4 of the diameter of the screw (1, 1A, 1B).
B).

[3] The screw (1, 1A, 1B)
Is a screw (1, 1A, 1B) for a resin extruder according to [1] or [2], wherein the number of peaks in the entire length is approximately 19 to 36.

[4] The screws (1A, 1B)
It comprises a shank part (2) for connecting to a power source side and a flight part (3) extending by the effective length, and the flight part (3) is fed with resin from a base end side located on the hopper side. A biting portion (N1) having a predetermined diameter for taking in and feeding the raw material resin supplied from the hopper in order toward the direction, and a primary kneading and pressing portion (D1) whose diameter gradually increases from the tip of the biting portion (N1). N2-1), a secondary kneading / pressing unit (N2-2) whose diameter gradually increases from the tip of the primary kneading / pressing unit (N2-1), and a secondary kneading / pressing unit (N
Kneading and compressing section (N3) having almost the same diameter as the maximum diameter of the tip of 2-2)
(1A, 1B). The screw (1A, 1B) for a resin extruder according to [1], [2] or [3].

[5] The secondary kneading and pressurizing section (N2-2)
The screw for a resin extruder according to [4], wherein the screw is formed such that the diameter gradually increases at a larger inclination angle stepwise than the tip of the primary kneading pressurizing section (N2-1). (1A, 1B).

[6] The screw (1A, 1B) for the resin extruder according to the above [4] or [5] is connected to the cylinder (10).
0A, 100B) in a rotatable manner, wherein the inner diameter of the cylinder (100A, 100B) is the biting portion (N1) of the screw (1A, 1B) and the primary kneading press. In the first portion (R1) where the portion (N2-1) is located, a predetermined wide gap is generated with respect to the bite portion (N1) which is larger than the maximum diameter of the tip of the primary kneading pressurizing portion (N2-1). In the third portion (R3) where the kneading and compressing section (N3) is located, the size is uniformly set to a predetermined narrow gap with respect to the kneading and compressing section (N3). , The secondary kneading pressurizing section (N
The second portion (R2) where 2-2) is located is set as a decompression region where the inner diameter gradually increases from the first portion (R1) toward the third portion (R3). Machine.

[7] The cylinder (100A, 100A
The ratio of the narrow gap to the wide gap in the gap between the inner wall of B) and the outer periphery of the screw (1A, 1B) is set to approximately 3.5 to 4.5 [6]. The resin extruder as described.

[8] The flight section (3) of the screw (1A, 1B) includes the biting section (N1), the primary kneading / pressing section (N2-1), and the secondary kneading / pressing section (N2-2). ), Following the kneading and compression section (N3), in the resin feeding direction,
A decompression section (N4) whose diameter is gradually reduced, and the decompression section (N4)
A deaeration section (N5) having substantially the same diameter as the tip minimum diameter, a pressurizing section (N6) whose diameter gradually increases, and an extrusion section (N7) having substantially the same diameter as the tip maximum diameter of the pressurization section (N6). ), And the cylinder (100A, 100B) is provided with an inlet (140) through which an auxiliary agent can be injected from the outside toward the inner wall where the downstream side of the degassing part (N5) of the screw (1A, 1B) is located. ), The resin extruder according to [6] or [7].

Next, the operation based on the above-mentioned solution will be described. In the screw (1) for a resin extruder according to the present invention, the ratio of the effective length to the diameter of the flight portion (3) is approximately 7%.
, The effective length of the screw (1) can be shortened, and the resin feed speed is reduced even at the same rotational speed as in the prior art.
0) Not only the time pressed against the inner wall becomes longer, but also the resin charged into the cylinder (100) is sufficiently filled between the pitches of the screw (1), so that the thermal efficiency is improved and the kneading property is improved, Slip can be reduced and the resin feeding efficiency can be improved.

If the pitch of the screw (1) is formed at a ratio of 1/4 to 3/4 of the diameter of the screw (1), the screw (1) has a diameter of 10 mm.
In the case of 0 mm, the pitch interval of the screw (1) is 25 mm to 75 mm in proportion to the total length of the flight portion (3).
Since it is formed in the range of mm, it can be selected according to the molding conditions of various resins, and it is possible to cope with production of many kinds and small lots.

If the number of ridges in the entire length of the screw (1) is approximately 19 to 36, the number of ridges can be adjusted in the range of 19 to 36 even if the entire length of the screw (1) is shortened. Since it is the same as the conventional case, the volume of the resin filled and stored between the pitches of the screw (1) is reduced, and the transfer power can be reduced.

According to the screw (1) for a resin extruder as described above, a single screw (1) can cope with the production of various resins, but special resins such as liquid crystal polymers are kneaded. If the properties (coloring) are somewhat poor and the kneading properties are to be improved, a situation in which the productivity is somewhat reduced may be considered.

More specifically, in the case of the dimensions illustrated in FIGS. 2 to 4, when the raw resin is charged from the hopper (material charging port (140)) at the base end side of the cylinder (100), the raw resin becomes a screw ( Biting part of 1) (N1)
It is sent to the kneading compression section (N3) side (gap dimension 3.5) from the kneading press section (N6) through (kneading dimension 11.5) and the kneading property. Then, the gap size on the kneading compression section (N3) side is set to 2.5 to 3
I have to set to.

However, here, the biting portion (N1)
If the gap size on the side is kept at 11.5, the balance between the degree of melting of the resin on the kneading compression section (N3) side (gap dimension 3.5) and the pushing amount on the biting section (N1) side will be improved. Bad, causing surging (flow stagnation). Therefore, the clearance dimension on the biting portion (N1) side is set to 10.
It is conceivable to set the balance to 5 to 9.0,
As a result, productivity may be reduced, or a special screw for a special resin may be required.

In general, the compression ratio, which is the ratio of the gap size between the biting portion (N1) side and the kneading compression portion (N3) side of the screw (1), is set to about 3.0 to 3.2. However, even with such a compression ratio, the special resin does not melt evenly, so that surging occurs, and the way in which the strands come out is not uniform, which may cause trouble.

Therefore, in order to optimally cope with a special resin, the screw (1) for a resin extruder according to the present invention is further provided.
A, 1B), the flight portion (3) extending by the effective length is sequentially cut in the resin feeding direction in the biting portion (N
1), a primary kneading / pressing unit (N2-1), a secondary kneading / pressing unit (N2-2), and a kneading / compressing unit (N3).

Corresponding to the screw (1A, 1B), the biting portion (N) of the screw (1A, 1B) in the inner diameter of the cylinder (100A, 100B).
1) and the first kneading and pressurizing section (N2-1)
The part (R1) is uniformly set to a size larger than the maximum diameter of the tip of the primary kneading pressurizing part (N2-1) and a predetermined wide gap is formed with respect to the biting part (N1). The third portion (R3) where the compression section (N3) is located is uniformly set to have a predetermined narrow gap with respect to the kneading compression section (N3). The second region (R2) where -2) is located is set as a decompression region in which the inner diameter gradually increases from the first region (R1) toward the third region (R3).

According to the resin extruder provided with such screws (1A, 1B) and cylinders (100A, 100B), the raw material resin supplied from the hopper first receives the bites (1A, 1B) of the screws (1A, 1B). N1) and a relatively large amount is efficiently taken into the wide gap between the first portions (R1) of the cylinders (100A, 100B), and the primary kneading and pressurizing portion (N2-1) is formed in the first portions (R1). ) And gradually pressurized.

Subsequently, the resin is sent to the secondary kneading and pressurizing section (N2-2) of the screw (1A, 1B). The secondary kneading and pressurizing section (N2-2) is connected to the primary kneading and pressurizing section. (N2-
Since the diameter gradually increases as compared with 1), the resin that has started to melt is further pressed. Moreover, the secondary kneading pressurizing section (N2-
The second portion (R2) in the cylinder (100A, 100B) where 2) is located is set as a decompression region in which the inner diameter gradually increases, and the pressure of the resin flow is also reduced.

Accordingly, the secondary kneading pressurizing section (N2-2)
In the gap between the second part (R2) and the second part (R2), decompression of the flow of the resin and pressurization for promoting the degree of dissolution are simultaneously performed, so that the dissolution efficiency and kneading properties are remarkably improved. The sufficiently melted and kneaded resin is sent to the kneading compression section (N3) having substantially the same diameter as the maximum diameter of the tip of the secondary kneading and pressurizing section (N2-2) without causing unevenness in the flow. .

Cylinder (100A, 100B) in which kneading and compressing section (N3) of screw (1A, 1B) is located
The third portion (R3) is uniformly set to have a predetermined narrow gap with respect to the kneading and compressing portion (N3).
The resin sent to such a narrow gap is already uniformly dissolved and kneaded as described above. Therefore, the dimensions of the narrow gap can be set to be narrow so that more kneading properties can be obtained, so that perfect kneading can be performed without reducing the productivity of any kind of special resin. It can be carried out.

More specifically, the cylinder (100A,
100B) of the gap between the inner wall of the screw and the outer circumference of the screw (1A, 1B), the ratio of the narrow gap to the wide gap.
If it is set to approximately 3.5 to 4.5, kneading properties and productivity can be further improved.

In such a resin extruder,
Screw (1A) to cylinder (100A, 100B)
It is possible to provide an inlet (140) through which an auxiliary agent can be injected from the outside toward the inner wall where the downstream side of the degassing section (N5) of (A, 1B) is located.

Thus, an auxiliary agent such as wood flour, carbon black, titanium oxide, or ferrer (mineral) having a specific gravity greatly different from that of the raw material resin is appropriately introduced from the input port (140), whereby the raw material resin and the auxiliary agent are added. Can be easily manufactured in a desired ratio.

[0041]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Various embodiments representing the present invention will be described below with reference to the drawings. FIG. 1 is an overall side view of a screw for a resin extruder according to a first embodiment of the present invention.

The resin extruder screw 1 is rotatably housed in the cylinder 100 shown in FIGS. 2 and 3 as described above, and melts and kneads the resin supplied from the hopper by rotation feed, and extrudes the resin. It is formed by a shank portion 2 connected to the power source side and a flight portion 3 extending by an effective length.

In the flight section 3 of the screw 1 for a resin extruder according to the present embodiment, the ratio of the effective length L to the diameter D is set to approximately 7 to 14 (preferably 14 where the overall balance is obtained). Because it is composed,
The lead angle α of the screw 1 is approximately 7 to 21 degrees (preferably 14 degrees).

The pitch interval P of the screw 1 is proportional to the flight portion length L2. If the diameter of the screw is D, it is formed in the range of 1/4 × D to 3/4 × D. Is 100 mm, the pitch interval P is formed in the range of 25 mm to 75 mm, and the number of screw lead portions in the flight portion length L2 is 19 to
36 (preferably 28 to 30 as the number of peaks at which kneading is sufficiently performed).

Therefore, if the diameter D is 100 mm, the ratio of the effective length L2 to the diameter D is approximately 7 to 14 (preferably 14).
00 to 1400 mm (preferably 1400 m
m), when the shank length L1 is 280 mm, the total length is 980 to 1680 mm (preferably 1680 mm). Here, when the diameter D of the screw 1 is 50 mm and the pitch interval P is 25 mm, the effective length L2 of the flight portion can be halved.

According to the resin extruder screw 1 configured as described above, the screw 1 is rotated by 100
pm, and the resin is injected into the cylinder 100 of the resin extruder from the hopper. The resin is melted and kneaded sequentially by the rotation of the flight unit 3 screw, and the melted resin is fed from the die head at the tip of the resin extruder. Extruded.

The strands that are continuously melted and discharged from the die head while being formed into a small-diameter linear shape in a molten state are drawn into a water tank, cooled with water, and then drawn out of the water tank. And pelletized by a strand cutting machine.

Here, the flight portion 3 screw is configured such that the ratio of the effective length L2 to the diameter D is 14 (7-14) and the lead angle α is 14 degrees (7-14 degrees). , At the same speed as before, the feed rate is halved,
In particular, in the scorch occurrence area, the resin is filled between the pitches P and fills up to the scorch occurrence part, so that the occurrence of scorch is reduced.

Further, since the resin charged into the cylinder 100 is sufficiently filled in each pitch interval P of the screw 1, the time for which the resin presses the inner wall of the cylinder 100 is increased, and the thermal efficiency is improved. It is well fluidized even at a temperature lower by 10 ° C. or more than a normal screw, improves the degree of kneading, and can cope with a wide range of resin molding conditions. Therefore, one screw can cope with various resins.

The number of revolutions is the same as that of the prior art. Even if the feed speed of the resin is reduced, the slip is remarkably reduced, so that not only the thermal efficiency is improved but also the scorch is reduced. , Quality can be improved.

Further, since the occurrence of scorch is reduced, a large amount of waste generated due to decolorization of the color generated at the scorch generating source during setup change during color change, and the waste The waste time for flowing out can be greatly reduced.

In addition, since the entire length of the screw has been reduced, the cylinder 10 can be used during setup change for color change.
From 0, the screw 1 can be easily taken in and out, and the setup time for cleaning and the like has been one hour in comparison with the conventional resin production time of 30 minutes, but this can be reduced to about 5 minutes, and the conventional waste time is reduced. Can be reduced to 1/12.

In addition, since the total length of the screw is reduced and the feed speed is reduced, in the case of the conventional L / D ratio 28, the motor output 55 Kw and the heater power consumption 23 Kw make a total of 78 Kw. In the screw of the present embodiment, the power consumption is the same as the output and the motor output 22
The power consumption can be halved to a total of 37 Kw of Kw and the capacity of the heater of 15 Kw, and the floor area occupied by the entire apparatus can be significantly reduced to save space.

This is the same in an injection molding machine.
It is also effective for an injection molding machine that requires a long measuring time due to slip, and thus a long molding time.

Further, the resin extruder screw 1 and the cylinder 100 having the dimensions illustrated in FIGS. 2 to 4 will be described.

The flight portion 3 of the screw 1 for a resin extruder shown in FIG. 4 includes a biting portion N1 for taking in and feeding the raw material resin in order from the base end located on the hopper side (not shown) toward the resin feeding direction. A kneading pressurizing section N2 whose diameter gradually increases from the tip of the biting section N1, a kneading compressing section N3 having the same diameter as the maximum diameter of the tip of the kneading pressurizing section N2, a short pressure reducing section N4 whose diameter gradually decreases, and the decompression. It is divided into a deaeration section N5 having the same diameter as the tip end minimum diameter of the section N4, a pressurizing section N6 whose diameter gradually increases, and an extrusion section N7 having the same diameter as the tip end maximum diameter of the pressurization section N6.

The inner diameter of the cylinder 100 shown in FIGS. 2 and 3 is set to a constant size over its entire length. Of the gap between the inner wall of the cylinder 100 and the outer circumference of the screw 1, the gap (1
In contrast to 1.5), the ratio of the gap (3.5) at the position where the kneading compression section N3 is located is set to about 3.3.

At the base end side of the cylinder 100, a material input port 110 for mounting a hopper is opened so as to communicate with the inside. A communicating vent 120 is provided. A die head 13 for extruding the melted resin as a strand is provided at the tip of the cylinder 100.
0 is provided. Although not shown, a heater is mounted on the outer peripheral side of the cylinder 100.

According to the resin extruder provided with such a screw 1 for a resin extruder and the cylinder 100, a single screw 1 can cope with the production of various resins. As for the resin, the kneadability (coloring) is somewhat poor, and if you try to improve the kneadability,
It is possible that productivity will decrease slightly.

More specifically, in the case of the dimensions illustrated in FIGS. 2 to 4, when the raw resin is charged from the hopper (material charging port 110) on the base end side of the cylinder, the raw resin is screwed into the biting portion N1 ( From the gap size 11.5) with the inner wall of the cylinder 100, it is sent to the kneading compression section N3 (gap size 3.5) through the kneading pressurizing section N2. It is necessary to increase the kneadability by setting the gap size on the N3 side to 2.5 to 3.

However, if the gap size on the biting portion N1 side is kept at 11.5, the kneading compression portion N
The balance between the degree of melting of the resin on the 3 (gap size 3.5) side and the amount of pressing on the side of the biting portion N1 is poor, causing surging. Therefore, biting part N
It is conceivable to balance by setting the gap size on one side to 10.5 to 9.0, but as a result, the supply amount of resin per unit time decreases, resulting in a decrease in productivity or a special resin. A special screw is required.

The compression ratio, which is the ratio of the gap size between the biting portion N1 side and the kneading compression portion N3 side of the screw 1, is set to about 3.3. Since such a resin does not melt uniformly, surging occurs, and the way the strands come out is not uniform, which may cause trouble.

Therefore, in order to optimally cope with a special resin, the flight portion 3 extending by the effective length is used as the screw 1A of the resin extruder according to the second embodiment shown in FIGS. Biting portion N in order toward the direction
1. Primary kneading and pressurizing section N2-1, secondary kneading and pressurizing section N2-
2, kneading and compressing sections N3,...

As shown in FIG. 7, the primary kneading and pressurizing portion N2-1 of the screw 1A according to the second embodiment is a portion whose diameter gradually increases from the tip of the biting portion N1. The kneading and pressurizing section N2-2 is a primary kneading and pressurizing section N2.
This is a portion where the diameter gradually increases at a larger inclination angle than the tip of -1.

The kneading and compressing section N3 following the secondary kneading and pressurizing section N2-2 extends approximately the same diameter as the maximum diameter of the tip of the secondary kneading and pressurizing section N2-2. Each section of the section of the screw 1A from the kneading compression section N3 to the extruding section N7 at the tip is common to the screw 1 for a resin extruder according to the above-described first embodiment.

The cylinder 100A corresponding to the screw 1A has a primary kneading and pressurizing portion N2 at the first portion R1 where the biting portion N1 and the primary kneading and pressurizing portion N2-1 of the screw 1A are located. -1 is uniformly set to a size that is larger than the tip maximum diameter and that a predetermined wide gap (13.0) is generated with respect to the biting portion N1.

The third kneading and compression section N3 is located
In the part R3, the size is uniformly set to a size where a predetermined narrow gap (3.0) is generated with respect to the kneading compression part N3.
The second region R2 where the secondary kneading and pressurizing portion N2-2 is located is set as a "decompression region" in which the inner diameter gradually increases from the first region R1 toward the third region R3.

The screw 1A and the cylinder 1
According to the resin extruder equipped with the material input port 110A,
First, a relatively large amount of the raw material resin is efficiently taken into a wide gap (13.0) between the biting portion N1 of the screw 1A and the first portion R1 of the cylinder 100A, and the first portion R1 , And is gradually pressurized while being sent to the primary kneading pressurizing section N2-1.

Subsequently, the resin is sent to the secondary kneading and pressurizing section N2-2 of the screw 1A.
In the case of -2, since the diameter gradually increases at an inclination angle larger than that of the primary kneading pressurizing section N2-1, the resin that has begun to melt is further pressed. Moreover, the second portion N2 in the cylinder 100A where the secondary kneading and pressurizing portion N2-2 is located is set as a "decompression region" in which the inner diameter gradually increases, and the pressure of the resin flow is also reduced.

Thus, in the gap (amplifying region, pressurizing / depressurizing region) between the secondary kneading pressurizing section N2-2 and the second portion R2, pressure reduction for the resin flow and pressurization for promoting the degree of dissolution are performed. Are performed at the same time, and the dissolution efficiency and the kneading property are remarkably improved. The sufficiently melted and kneaded resin is free from unevenness in the flow manner, and the secondary kneading pressurizing section N2-
2 is fed to the kneading / compressing unit side N3 having substantially the same diameter as the maximum diameter of the tip.

The third portion R3 of the cylinder 100A where the kneading and compressing portion N3 of the screw 1A is located is
The width of the narrow gap (3.0) is uniformly set with respect to the size of the resin 3, and the resin fed into the narrow gap (3.0) is already uniformly melted and kneaded as described above. Have been. Therefore, the size of the narrow gap can be set to be narrow so that more kneadability can be obtained, as in the dimension example (3.0) of the present embodiment. Even more complete kneading can be performed without lowering the productivity.

Here, of the gap between the inner wall of the cylinder 100A and the outer periphery of the screw 1A, the wide gap (1
The ratio of the narrow gap (3.0) to 3.0) is about 4.3, and this value is set in the range of 3.5 to 4.5, so that further kneading and productivity are further improved. Can be improved.

FIGS. 8 and 9 show a third embodiment of the present invention. In the present embodiment, the cylinder 100B has
There is provided an inlet 140 into which an auxiliary agent can be injected from the outside toward the inner wall where the downstream side of the deaeration section of the screw 1B is located.

The screw 1B is formed in substantially the same manner as the screw 1A of the second embodiment, and has the same sectional shape from the biting portion N1 to the deaeration portion N5. In 1B, a pressure reducing portion N5-1 having a slightly reduced diameter is formed immediately downstream of the pressure reducing portion N4,
Further on the downstream side, there is formed an input port corresponding portion N5-2 extending at the same diameter as the tip minimum diameter of the pressure reducing portion N5-1.
In addition, a pressurizing section N6 and an extruding section N7 which are common to the second embodiment are continued downstream of the input port corresponding section N5-2.

As described above, according to the resin extruder according to the third embodiment, the screw 1 is attached to the cylinder 100B.
The downstream side of the deaeration section N5 of B is located at the position (input port corresponding section N5-
2) It is possible to provide an inlet 140 into which an auxiliary agent can be injected from the outside toward the inner wall.

In the case where an auxiliary agent having a specific gravity greatly different from that of the raw material resin is mixed into the raw material, the auxiliary agent is initially added to, for example, wood powder 60% or more, carbon black 60% or more, titanium oxide, silica 80% or more, or 70% or more of ferrer (mineral), is not mixed from the hopper, but is appropriately added from the input port 140 so as to be mixed into the sufficiently kneaded resin. Can be easily manufactured in a desired ratio.

Accordingly, kneading properties comparable to those of a twin-screw extruder can be obtained, and further, low-temperature extrusion (30 to 5
(A temperature setting as low as 0 ° C.) is also possible, and a product with extremely little resin degradation can be obtained. In addition, it is possible to handle resin raw materials such as agricultural vinyl for houses, which are kept on soil and dust.

Although the embodiments of the present invention have been described with reference to the drawings, the specific structure is not limited to these embodiments, and even if there are changes and additions without departing from the gist of the present invention, the present invention will be described. Included in the invention.

Specifically, for example, the secondary kneading pressurizing section N2 of the screws 1A and 1B according to the second and third embodiments is used.
-2 is formed so that the diameter gradually increases at a larger inclination angle more gradually than the tip of the primary kneading and pressurizing portion N2-1 immediately before, but almost the same as the primary kneading and pressurizing portion N2-1. The diameter may be gradually increased so as to smoothly continue at an appropriate inclination angle.

[0080]

The present invention has the following effects.

(A) According to the first aspect of the present invention, since the ratio of the effective length to the diameter of the flight portion is approximately 7-14, the effective length of the screw can be reduced.
Since the resin feed speed is reduced even at the same rotation speed as before, not only does the time that the resin is pressed against the inner wall of the cylinder become longer, but also the resin injected into the cylinder is sufficiently filled between the screw pitches In addition, the heat efficiency is improved and the kneading property is improved, the slip is reduced, and the resin feeding efficiency can be improved.

(B) According to the second aspect of the present invention, the pitch interval of the screw is 1/4 of the diameter of the screw.
When the screw diameter is 100 mm, the pitch interval of the screw is formed in the range of 25 mm to 75 mm in proportion to the total length. Can be selected in accordance with the requirements, and it is possible to cope with multi-kind, small-lot production.

(C) According to the third aspect of the present invention, since the number of peaks in the entire length is approximately 19 to 36,
Even if the overall length of the screw is shortened, the number of peaks can be adjusted in the range of 19 to 36, which is the same as the conventional case. Therefore, the volume of resin filled and stored between the pitches of the screw is reduced, and the transfer power can be reduced. .

(D) According to the invention according to claims 4 to 7,
Decompression of the resin flow and pressurization that promotes the degree of dissolution are performed simultaneously, so that the flow of the resin will not be uneven and the productivity of any type of special resin will be reduced. And more complete kneading can be performed.

(E) According to the eighth aspect of the present invention, an auxiliary agent such as wood flour, carbon black, titanium oxide, or ferrer (mineral) having a specific gravity greatly different from that of the raw material resin is appropriately introduced from the inlet. In addition, a raw material in which the raw material resin and the auxiliary agent are uniformly mixed at a desired ratio can be easily manufactured.

[Brief description of the drawings]

FIG. 1 is an overall side view showing a screw for a resin extruder according to a first embodiment of the present invention.

FIG. 2 is a side view showing a main part of the resin extruder provided with the resin extruder screw according to the first embodiment of the present invention.

FIG. 3 is an overall side view showing a cylinder accommodating a resin extruder screw according to the first embodiment of the present invention.

FIG. 4 is an overall side view showing a sectional shape of the resin extruder screw according to the first embodiment of the present invention.

FIG. 5 is a side view showing a main part of a resin extruder according to a second embodiment of the present invention.

FIG. 6 is an overall side view showing a cylinder of a resin extruder according to a second embodiment of the present invention.

FIG. 7 is an overall side view showing a sectional shape of a screw for a resin extruder of a resin extruder according to a second embodiment of the present invention.

FIG. 8 is a side view showing a main part of a resin extruder according to a third embodiment of the present invention.

FIG. 9 is an overall side view showing a cylinder of a resin extruder according to a third embodiment of the present invention.

FIG. 10 is an overall side view showing a sectional shape of a screw for a resin extruder of a resin extruder according to a third embodiment of the present invention.

FIG. 11 is an overall schematic view of a conventional pellet manufacturing apparatus.

FIG. 12 is an overall side view showing a conventional screw for a resin extruder.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 ... Screw 1A ... Screw 1B ... Screw 2 ... Shank part 3 ... Flight part 4 ... Screw lead part D ... Diameter L1 ... Shank part length L2 ... Flight part length P ... Pitch interval N1 ... Biting part N2 ... Kneading press Part N2-1: Primary kneading and pressurizing part N2-2 ... Secondary kneading and pressurizing part N3 ... Kneading and compressing part N4 ... Depressurizing part N5 ... Deaeration part N5-1 ... Depressurizing part N5-2 ... Input port corresponding part N6 ... Pressing part N7 ... Extruding part 100 ... Cylinder 100A ... Cylinder 100B ... Cylinder 140 ... Input port

Claims (8)

[Claims] 1. A raw material resin which is rotatably accommodated in a cylinder and fed from a hopper is melted by rotation feed.
In the screw for a resin extruder to be kneaded and extruded, the screw for the resin extruder has a ratio of an effective length to a diameter of about 7 to 14, and a lead angle of the screw is formed at an inclination of about 7 to 21 degrees. A screw for a resin extruder. 2. The screw for a resin extruder according to claim 1, wherein a pitch interval of said screw is formed in a ratio of 1/4 to 3/4 with respect to a diameter of said screw. 3. The screw for a resin extruder according to claim 1, wherein said screw has a number of ridges of about 19 to 36 in its entire length. 4. The screw includes a shank portion for connecting to a power source side and a flight portion extending by the effective length, wherein the flight portion feeds resin from a base end side located on the hopper side. In order, a biting portion having a predetermined diameter for feeding and taking in the raw material resin supplied from the hopper, a primary kneading pressurizing portion whose diameter gradually increases from the tip of the biting portion, and a primary kneading press. The secondary kneading and pressurizing section is further divided at least into a secondary kneading and pressurizing section whose diameter gradually increases from the tip of the section and a kneading and compressing section having a diameter substantially equal to the maximum diameter of the tip of the secondary kneading and pressing section. Item 6. A screw for a resin extruder according to Item 1, 2 or 3. 5. The secondary kneading and pressurizing section is formed such that its diameter gradually increases at a larger inclination angle than the tip of the primary kneading and pressurizing section.
The screw for a resin extruder according to the above. 6. A resin extruder comprising the screw for a resin extruder according to claim 4 or 5 rotatably housed in a cylinder, wherein the inner diameter of the cylinder is a biting portion of the screw and primary kneading. In the first portion where the pressurizing portion is located, it is uniformly set to be larger than the maximum diameter of the tip of the primary kneading pressurizing portion and to have a predetermined wide gap with respect to the biting portion,
In the third portion where the kneading / compressing portion is located, the size is uniformly set to have a predetermined narrow gap with respect to the kneading / compressing portion, and the second portion where the secondary kneading / pressing portion is located is A resin extruder characterized by being set as a decompression region in which an inner diameter gradually increases from a first portion to a third portion. 7. The ratio of the narrow gap to the wide gap in the gap between the inner wall of the cylinder and the outer periphery of the screw is set to approximately 3.5 to 4.5. The resin extruder as described. 8. A depressurizing section in which the diameter of the screw gradually decreases in the resin feeding direction following the biting section, the primary kneading press section, the secondary kneading press section, and the kneading compression section. And, a deaeration section having a diameter substantially the same as the tip minimum diameter of the decompression section, a pressurizing section whose diameter is gradually increased, and at least a section extruded with a diameter substantially equal to the tip maximum diameter of the pressurization section, The resin extruder according to claim 6 or 7, wherein the cylinder is provided with an input port through which an auxiliary agent can be input from the outside toward an inner wall where a downstream side of the deaeration section of the screw is located.