JPH0474608A - Kneading method and kneading device in biaxial kneading apparatus - Google Patents

Abstract

PURPOSE:To prevent a material to be kneaded from suddenly invading a kneading chamber situated at the rear of the kneading chamber to which the material is placed by previously blowing oxidation inhibiting gas toward a kneading chamber from the rear of the kneading chamber. CONSTITUTION:In a biaxial kneading apparatus wherein a material to be kneaded is forwarded to the axially directional one-end side of a rotor 4 while kneading the material to be kneaded in respective kneading chambers 2, 3, oxidation inhibiting gas is blown previously from the rearmost end side of the kneading chamber 2 to the inside of the kneading chamber 2, and after the gas reaches the kneading chambers 2, 3 where kneading is conducted, any one of supplying ports 5, 6 is selected from which the material to be kneaded is placed, and then a rotor 4 is rotated for effecting the kneading and transporting of the material to be kneaded. Thus, the material to be kneaded as powder is prevented from entering the rear side of the kneading chambers 2, 3, there is no need for the kneading chambers 2, 3 and rotor 4 or the like to be cleaned even in the case of grade-changing in strong kneading and weak kneading, and therefore the range of resin producible by one line (kneading apparatus) is extended substantially.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a kneading method in a twin-screw kneader and to kneading equipment for direct use in carrying out the method.

(Conventional technology) In the kneading industry, with the recent diversification of resin products,
The number of orders for large quantities of the same grade at once, as in the past, is decreasing, and on the contrary, the number of orders for relatively small quantities of various grades is increasing.

As a person skilled in the art, conventionally, in order to meet such diversified needs, the rotor for bullets and the rotor for weak kneading must be replaced one after another, or the kneading device for bullets and the kneader for weak kneading must be installed in the factory. Generally speaking, there were only two options to take, such as installing two lines.

On the other hand, among the twin-screw kneading devices, one for bullets is
For example, there is one shown in FIG.

In the figure, 1 is a housing, and there are 2
Two kneading chambers 2 and 3 are formed side by side in the material conveyance direction, and a pair of rotors 4 and 4 are rotatably inserted into the kneading chambers 2 and 3 in parallel with each other. Reference numerals 5 and 6 indicate supply ports for the material to be kneaded, and one each is provided on the rear side (on the right side in FIG. 4) of each of the kneading chambers 2 and 3.

On the circumferential surface of the rotor 4, a feed portion 7 having a protruding feed blade 7 and a kneading portion 8 having a protruding kneading blade are formed separately in the axial direction, and each portion 7,
8 are disposed in each of the kneading chambers 2 and 3, one set each, and the feed section 7 is located at the rear in the material conveyance direction.

Reference numeral 9 denotes a gate device, which is provided at the joining portion of the kneading chambers 2 and 3 and, in the case of this example, also on the discharge port 10 side of the housing 1. This gate device 9 consists of a pair of upper and lower gates 1 and 12, and a drive mechanism 13 for moving the gates 1L12 toward and away from each other.
The gap formed between the arc-shaped recess 14 formed on the joint end side of the rotor 4 and the ring part 15 formed between the feed part 7 and the kneading part 8 of the rotor 4 is By making various changes, it is possible to adjust the flow resistance of the material to be kneaded.

In the case of this example, the powdery material to be kneaded is mainly supplied from the supply port 5 on the rear side, and the material to be kneaded is kneaded in the kneading chamber 2 on the rear side. 1,
12 and is further kneaded in the kneading chamber 3 on the front side. In addition, the supply port 6 on the front side was provided because
This is mainly to adjust the degree of filling of the material in the front kneading chamber 3 by degassing the gas generated during kneading or by adding the material afterward, thereby making it possible to homogenize and control the product quality. It is said that

(Problem to be solved by the invention) Among the above conventional techniques, when the rotor is replaced one after another,
Because it takes too much effort, it is not possible to quickly respond to grade changes that should be made frequently.

Furthermore, in the case of installing two lines, it goes without saying that the equipment cost will be enormous, and furthermore, the operating efficiency will be low in comparison.

Therefore, in the bullet kneading device shown in Fig. 4, if the material to be kneaded is supplied from the beginning through the supply port 6 on the front side, has anyone suggested that it could also be used for weak kneading? Although it is possible to imagine this, in reality it is not so simple.

That is, as mentioned above, since the material to be kneaded is initially in powder form, if the material to be kneaded is introduced only from the front supply port 6, the gates 1 and 12 and the ring of the rotor 4 Part 1
Powdered material to be kneaded may sometimes enter the rear kneading chamber 2 through the gap between There is an inconvenience that the product may be mixed with the powder for use, resulting in a decrease in product quality.

Furthermore, in this case, if the powder remaining in the kneading chamber 2 is to be cleaned and removed when changing the grade, it will take more time and effort than when replacing the rotor.

The present invention has been made in view of the above circumstances, and by adding various improvements to the conventional bullet kneading device, it is possible to produce bullets on one line without the need for labor such as changing the rotor. The object of the present invention is to provide a kneading method and kneading equipment in a twin-screw kneading device that can be used for both wire kneading and weak kneading.

(Means for solving the problem) The technical means taken by the present invention to achieve the above object are as follows:
It is as shown below.

That is, the invention described in claim (1) consists of a pair of rotors 4, 4 inserted into a plurality of kneading chambers 2, 3 arranged in the material transport direction, each having a supply port 5, 6 for the material to be kneaded. A pair of gates 1L that partition the kneading chambers 2 and 3 by mutual rotation.
While adjusting the flow resistance of the material to be kneaded by approaching and separating the material to be kneaded, the material to be kneaded is fed to one end in the axial direction of the rotor 4 while being kneaded in each of the kneading chambers 2 and 3. In a kneading method using an axial kneading device, a pre-oxidation preventing gas is blown into the kneading chamber 2 from the rearmost side of the kneading chamber 2 located at the rearmost side in the direction of conveyance of the materials to be kneaded, and the gas is used to carry out the kneading. After reaching the kneading chambers 2 and 3, - select one of the supply ports 5 and 6 and input the material to be kneaded therefrom, and rotate the rotor 4 to knead and mix the material to be kneaded. It is characterized by carrying out transportation.

Further, the invention according to claim (2) provides that the housing 1 includes:
A plurality of kneading chambers 2, 3 are formed, each having a supply port 5.6 for the material to be kneaded and arranged in the material transport direction.
3, a pair of rotors 4 for kneading and transporting materials to be kneaded;
4 is rotatably inserted through the kneading chambers 2 and 3, and a gate device 9 is provided at the connecting portion of each of the kneading chambers 2 and 3, and the flow resistance of the material to be kneaded can be adjusted by approaching and separating a pair of gates 11 and 12. In the axial kneading device, among the supply ports 5 and 6, at least the supply ports 5 other than the supply port 6 located at the frontmost side in the material conveyance direction include the supply port 5.
An opening/closing lid 25 is provided on the outside of the housing 1 to allow the inside of the kneading chamber 2 to be sealed.
. It is characterized in that a gas injection means 30 is provided for blowing in a prevention gas to ventilate the inside of each kneading chamber 2, 3 from the rear.

(Function) In FIG. 1, the material to be kneaded is supplied into the kneading chambers 2, 3 from either one of the supply ports 5, 6 by the switching conveyance means 17.

At this time, a gas injection means 30 is provided further rearward of the kneading chamber 2 located at the rearmost side in the direction of conveyance of the materials to be kneaded, from which an antioxidant gas is blown in advance toward the kneading chamber 2. ing.

This anti-oxidation gas is not only vented to the kneading chamber 2 on the rearmost side, but also to the next one from the gap between the upper and lower gates 11, 12 of the gate device 9 and the rotor 4, provided that the kneading chamber 2 is sealed. It will be blown out into the kneading chamber 3.

Therefore, the initially powdered materials to be mixed that are introduced from the respective supply ports 2 and 3 are prevented from accidentally entering the drive part of the rotor 4 or the kneading chamber 2 located behind the mixing chamber 3 into which the materials to be mixed are introduced. is prevented.

(Example) Hereinafter, an example of the present invention will be described based on the drawings.

Since the basic structure of the kneading device itself is almost the same as that of the conventional kneading device, basic members such as the rotor 4 will be given the same reference numerals and explanation thereof will be omitted, and the characteristic structure will be described first.

In addition, the kneading chamber 2 on the rear side in the material conveyance direction will be called the first kneading chamber, and the kneading chamber 3 on the front side will be called the second kneading chamber. is the second
We will distinguish them by adding .

FIG. 1 illustrates an overview of the kneading equipment according to this embodiment.

In the same figure, 17 is a switching conveyance means, and from the top of the figure, a main hopper 18, a main feeder 19 connected below the hopper 18, and a switching means such as a rotary valve provided on the discharge side of the feeder 19. 20, first and second feeders 2L22 alternatively connected to the discharge side of the means 20;
, and first and second pumps 23 and 24 respectively connected to the discharge side of the feeder 2L22.

Opening/closing lids 25.26 are provided below the first and second hoppers 23.24, respectively, and the kneading chambers 2 and 3 can be closed or opened by opening and closing the lids 25.26. .

In Fig. 1, 27 and 28 are pressurizing means such as compressors, which blow anti-oxidation gas, in this example nitrogen gas, into appropriate places in the system of the kneading equipment to remove the materials to be kneaded in the system. This is to prevent oxidation (deterioration).

Among these, one pressurizing means 27 is connected to the main hopper 18, the first and second hoppers, and the ida 2122 via a pressurizing pipe 29, and the inside of the switching conveying means 17 system is filled with nitrogen gas. The other pressurizing means 28 is installed at the rearmost side of the housing 1 (on the right side in FIG. 1), and the pressurizing means 28 is installed at the rearmost side of the housing 1 (right side in FIG. The inside of the kneading device system is filled with nitrogen gas.

In this embodiment, the gas injection means 30 includes a housing 1
The kneading chamber 2 is composed of a casing 31 installed further rearward of the first kneading chamber 2 inside, an injection ring 32 and an oil seal 33 fitted to the inner surface of the casing 31, and an injection nozzle 34.

As shown in FIG. 2, the shaft portion 4a of the rotor 4 is loosely fitted into the casing 31, and its peripheral surface is sealed by the oil seal 33, so that a space 35 is formed in front of the seal 33. Furthermore, the nitrogen gas injected from the nozzle 34 within the space 35 has a flow velocity in the flow path between the injection ring 32 and the shaft portion 4a, as shown by the arrow U in the figure. is increased, and is injected into the first kneading chamber 2 through the periphery of the ring portion 36 of the rotor 4.

A gear pump 38 is connected to the lower part of the discharge port 10 of the second kneading chamber 3, and a beletizer (granulator) 39 is connected to the discharge side thereof via an L-shaped pipe 40.
A continuous resin granulation system is configured together with the axial kneading device.

The gear pump 38 has a pressure adjustment function, so that the amount of molten material to be kneaded discharged from the second kneading chamber 3 can be adjusted thereby.

Moreover, all 41 are pressure equalizing pipes, and in this embodiment, they are connected to each pumper 1B, 23, 24 and feeder 2L22, and the tip thereof is connected to a dust collector such as a bag filter (not shown). Therefore, all of the nitrogen gas filling the system is discharged to the outside of the system through this pressure equalizing pipe 41, and the pressure within the system is set to be slightly higher than atmospheric pressure.

Next, a kneading method using the kneading equipment having the above configuration will be explained along with its effects.

First, for example, when you want to knead and produce high-density polyethylene film grade, that is, material for thin film products,
Strongly knead the materials to be kneaded (specific energy 0.25KWH/kg
degree), but in this case, switching means 2
0 on the first feeder 21 side, and the material to be kneaded is introduced from the first supply port 5, with the first opening/closing lid 25 left in between.

At this time, the material to be kneaded is in powder form as described above, but in this case, nitrogen gas is blown into the first kneading chamber 2 from the rear by the gas injection means 30, and the first supply port 5 Since the powder escapes to the side, the powder is prevented from entering the drive section side of the rotor 4 and adversely affecting the gear mechanism and the like.

In this case, the introduced materials to be kneaded are once fed and kneaded in the first kneading chamber 2, and then kneaded again in the second kneading chamber 3 through the kneading degree adjustment by the gate device 9, and then hard kneaded. It will be provided.

Next, for example, when you want to knead and produce injection grade or blow grade high-density polyethylene, that is, a material for injection molding or blow molding, the materials to be kneaded are lightly kneaded (specific energy 0.15 KWH/kg).
degree), but in this case, switching means 2
0 is set on the second feeder 22 side, the material to be kneaded is introduced from the second supply port 6, the second opening/closing lid 26 is left open, and the first opening/closing lid 25 is closed.

In this case, the nitrogen gas blown into the first kneading chamber 2 by the injection means 30 flows through the same chamber 2 and reaches the gate device 9, as shown by the arrow ■ in FIG. In the gap between the ring part 15 of the rotor 4 and the ring part 15 of the rotor 4, the flow speed is increased, and the mixture comes to be ejected into the second kneading chamber 3, and finally passes through to the second supply rotor 6 side.

Therefore, the material to be kneaded in the form of powder introduced from the second supply port 6 is transferred to the first supply port 6 by the blowing action of the nitrogen gas described above.
Intrusion into the kneading chamber 2 side is almost completely prevented.

It goes without saying that from now on, the material to be kneaded is fed and kneaded only in the second kneading chamber 3, and is subjected to weak kneading.

As described above, according to this embodiment, by injecting nitrogen gas from the rear end side of the first kneading chamber 2, deterioration of the materials to be kneaded is prevented, and the nitrogen gas is ) or the first kneading chamber 2 (in the case of weak kneading), it is possible to prevent the materials to be kneaded from entering the kneading chamber 2 (in the case of weak kneading), so even if the kneading device is used interchangeably for bullet kneading and for weak kneading, The materials to be kneaded will not remain in the kneading chambers 2 and 3 unexpectedly. Therefore, even when the grade is changed frequently, the next kneading can be carried out without maintenance such as cleaning the inside of the kneading chamber 23, and one line (kneading device) can be used for both projectile kneading and weak kneading. It becomes a reality that it can be used for

Although one embodiment of the present invention has been described above, the present invention is not limited to this.

For example, the number of kneading chambers is not limited to two, and there may be three or more. In that case, it is necessary to additionally provide a supply port, a feeder in the switching conveyance means 17, a gate device 9, etc.

Furthermore, the antioxidant gas is not limited to nitrogen gas, but may also be an inert gas such as argon.

Furthermore, the switching conveyance means 17 is not limited to the above-mentioned configuration, but may be of any configuration as long as it can selectively convey materials to the respective supply ports 5 and 6.

Further, the second kneading chamber 3, that is, the kneading chamber 3 located at the frontmost side in the material transport direction, may not be provided with the opening/closing lid 25. That is, this is because there is no next chamber beyond the kneading chamber 3 into which the antioxidant gas is to be fed.

Further, the configuration of the gas injection means 30 is not limited to the above-mentioned one, and the gas may be directly blown into the kneading chamber 2 from an injection nozzle 34, as shown in FIG. 3, for example.

(Effects of the Invention) As explained above, according to the present invention, the antioxidant gas is injected from the rearmost side of the kneading chamber 2 located at the rearmost side in the material conveyance direction, and the antioxidant gas is The materials to be kneaded as powder are blown from the rear into the kneading chambers 2 and 3 to be kneaded in advance, and the material to be kneaded as a powder is blown into the kneading chambers 2 and 3 to be kneaded.
This prevents the possibility of intrusion into the rear side of the kneading chamber 2, even when changing grades between bullet and weak kneading.
, 3 and the rotor 4, etc., and thus the range of resins that can be produced by one line (kneading device) is greatly expanded.

[Brief explanation of drawings]

Figures 1 and 2 show an embodiment of the present invention, with Figure 1 being a schematic side view of the kneading equipment, Figure 2 being a longitudinal sectional view of the gas injection means, and Figure 3 being a modification of the gas injection means. FIG. 4 is a side sectional view of a conventional two-screw kneading device. 1-housing, 2, 3-kneading chamber, 4 rotor, 5.
6 - supply port, 9 - gate device, 11.12 gate, 17 - switching conveyance means, 25 - opening/closing lid, 30 gas injection means.

Claims (2)

[Claims] (1) A pair of rotors (4) (4) inserted into a plurality of kneading chambers (2) (3) arranged in the material conveyance direction each having a supply port (5) (6) for the material to be kneaded Due to rotation,
A pair of gates (11
) (12) While adjusting the flow resistance of the material to be kneaded by approaching and separating the material to be kneaded, the material to be kneaded is kneaded in each of the kneading chambers (2) and (3) while moving the material to be kneaded in the axial direction of the rotor (4). In a kneading method using a two-screw kneading device in which the materials are fed to one end, an anti-oxidizing compound is introduced into the kneading chamber (2) from the rearmost end of the kneading chamber (2) located at the rearmost side in the conveyance direction of the materials to be kneaded. Gas is blown into the kneading chamber (where the gas is mixed).
2) After reaching step (3), select one of the supply ports (5) and (6), input the material to be kneaded there, and rotate the rotor (4) to supply the material to be kneaded. A kneading method in a two-screw kneading device, characterized in that kneading and conveying are carried out. (2) A plurality of kneading chambers (2) and (3) are formed in the housing (1), each having a supply port (5) and (6) for the material to be kneaded and lined up in the material conveyance direction. )(3) is equipped with a pair of rotors (4)(
4) is rotatably inserted through the kneading chambers (2) and (3), and a gate is provided at the connection portion of each kneading chamber (2) and (3), and the flow resistance of the materials to be kneaded can be adjusted by approaching and separating a pair of gates (11) and (12). In the two-shaft kneading device provided with the device (9), among the supply ports (5) and (6), at least the supply port (5) other than the supply port (6) located at the frontmost side in the material conveyance direction, An opening/closing lid (25) that can seal the inside of the kneading chamber (2) corresponding to the supply port (5) is provided, and the housing (
1) is provided with a switching conveyance means (17) for selectively conveying the material to be kneaded to either one of the supply ports (5) and (6). Further behind the kneading chamber (2) on the rearmost side in the material transport direction,
Gas injection means (for blowing antioxidant gas into the kneading chamber (2) and ventilating the inside of each kneading chamber (2) and (3) from the rear)
30) A kneading equipment in a twin-screw kneading device characterized by being provided with.