JPS61241105A - Screw type extruding machine or kneading machine - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Field of Application] The present invention relates to a single-screw extruder or kneader. The term "extruder" used herein refers to all machines, such as so-called extrusion molding machines and injection molding machines, that move the processed material using a screw rotating inside a barrel. In addition, there is no particular limitation on the material to be processed in both the extruder and the kneading machine, and any material such as plastic, ceramic, metal particles, or composite materials may be used, but in particular, it is suitable for processing hard materials or at least materials containing hard materials. Are suitable.

[Conventional technology]

Various types of extruders or injection molding machines are used in the processes of melt spinning synthetic fibers and molding synthetic resins. In addition, hard fibrous materials such as glass fibers, metal fibers, inorganic fibers, carbon fibers, and various fillers are added to polymers during mixing of pigments, stabilizers, or titanium oxide, etc. prior to spinning, and during premixing and molding of resin composite materials. New materials and composite materials that can be mixed and molded into objects have been developed and put into practical use.

Conventionally, processing machines for such mixing, extrusion, pressurization, molding, etc. have all been made of steel, and in order to improve their wear resistance and salt resistance, they have been made of materials (alloys), plating, and different materials. It has been proposed and put into practical use to increase surface hardness by various means such as fusing materials.

[Problem that the invention seeks to solve]

However, along with the improvement in the functionality of the composite materials mentioned above, the heat resistance of the polymer materials has also improved, and the strength component materials to be mixed have become increasingly hard, resulting in the wear resistance of processing machines being lower than that of metals. Materials have reached their limits and are no longer sufficient. Therefore, it is necessary to frequently replace machine parts in a short period of time, which increases costs due to equipment replacement, reduces productivity, and makes molding conditions unstable (for example, the extruder may fluctuate greatly depending on the old and new machine due to significant wear). ) and other problems.

In addition, the mixing of iron and other metals into processed materials due to wear is a problem in recent processing of ultra-high purity materials.

[Means for solving problems]

In order to solve the above-mentioned problems, the present invention provides an extruder or a kneader that extrudes or kneads a material to be processed using a screw that rotates inside a container. The parts that require wear resistance are made of ceramic.

In order to solve the above-mentioned problems, it is possible to change the parts of the melt extruder, injection molding machine, kneading machine, etc. that come into contact with the processing materials to materials with excellent wear resistance and heat resistance, but inorganic materials ( For example, ceramic materials such as metal oxides), glass fibers, metal fibers, etc. have high hardness, and ceramic materials have hardness equal to or higher than these, have wear resistance, and can be used industrially at low cost. Only.

On the other hand, although ceramic materials have high hardness, they have low mechanical impact strength, toughness, coefficient of thermal expansion, thermal conductivity, etc. Must be made of metal. Therefore, only the parts that require particularly high wear resistance and hardness are made of ceramic, and the rest are made of metal.

Also, since ceramics lack toughness, they are particularly difficult to use when disassembling machines for repairs, cleaning, etc.
It is thought that chipping, cracking, cracking, etc. are likely to occur in the ceramic part, and in such a case, it is preferable to make it easy to individually replace the damaged part of the ceramic part.

Hereinafter, the structure of the screw according to the present invention will be specifically explained with reference to the drawings. First, an extrusion screw of a melt extruder will be explained as a representative example, but the same is basically applicable to a kneader and the like.

FIG. 1 shows an example of a melt extruder. In the figure, 1 is a screw, 2 is a barrel, and 3 is a hopper.

The raw material is supplied from a hopper 3, and is propelled by a screw 1 rotating in a barrel 2 into a propelling zone - compression zone - melting zone -
It moves from the lightweight zone (1) to the mixing zone (2), and during the movement, it is subjected to the actions of propulsion, compression, melting, metering, and mixing in each zone, and is extruded through the squeeze gate 4 and molded. In addition, this diagram shows the die, heating zone, cooling zone, vent, bearing,
The drive unit, weighing hopper, various measuring instruments, etc. are the same as those of a conventional melt extruder, so they are omitted from the diagram.

In the melt extruder shown in FIG. 1, the outer surfaces of the screw 1 and barrel 2, from the compression zone (2) to the melting zone (2) and the metering body (2), which are in contact with the material to be processed, are made of ceramic. Namely, the members of the screw 5.6.7.8.
9.10 and barrel members 11, 12, 13, 14
, 15, 16. member 17 of screw 1,
18 , 19 , 20 as well as the body of the barrel 2 and the hopper 3 are made of metal, generally steel.

Further, the members 5 to 10 are cylindrical, and the center portion is composed of one metal shaft.

Part 17, 1B of the screws in FIG.

19, 20 and the shaft body were not made of ceramic because the shaft body and member 20 are subject to torsional stress due to the driving force, and members 17, 19 are used at both ends when removing the screw for product changeover or cleaning. This is because the member 18 is easily damaged, and the solid material supplied from the hopper 3 hits the member 18. However, member 17
, 18 may be made of ceramic depending on the target material. Further, the main body of the barrel 2 is made of metal because it is a structural member and needs to have durability against external impacts.

However, the length of the part of the screw and barrel that comes into contact with the processing material that should be ceramicized is determined by the ceramic material, the life of the screw, the type of molded product, etc., and is limited to the example shown in Figure 1. It's not like that.

FIG. 2 shows, in cross-section, an example of a ceramicized part of the screw. Ceramic cylindrical body 5 having a spiral groove on the outer periphery
10 are fitted onto a metal shaft body 21. Part 1
7 and 18 also have a spiral groove on the outer periphery, but the shaft body 21
It may be integrated with or independent of. Further, it may be made of steel or ceramic, and the method of fixing it to the shaft body may be, for example, the method shown in FIG. 5. However, in order to connect the ceramic cylinders 5 to 10 to the shaft 21, one of the ends of the shaft must be split, at least initially.

When fixing the ceramic cylinders 5 to 10 to the shaft body 21, they may be bonded with an adhesive such as epoxy, melamine, or phenol, or the ceramic cylinders 5 to 10 may be fixed to the shaft body 21.
It may be attached to the shaft body 21 so that it can be removed (removed and replaced).

In the latter case, for example, the ceramic cylindrical bodies 5 to 10 can be fixed by threading the member 17 or the member 18 or 19 in the opposite direction with respect to the rotation of the screw with respect to the shaft body.

In addition, in an extruder, ceramic and metal have different coefficients of thermal expansion, so in order to absorb thermal changes during operation and to cushion the shock at the start of operation, the gap between the ceramic and metal parts is added as necessary. Alternatively, it is preferable to provide a buffer zone between the ceramic members. A buffer band is not particularly necessary when a ceramic member and a metal member are bonded together with an adhesive, as the adhesive acts as a buffer band, but when the ceramic member is removably attached,
Resins such as polyimide, polysulfone, and polyamide, films of heat-resistant synthetic polymers such as synthetic rubber, or foils such as copper and aluminum may be used, or epoxy,
It may also be formed by applying a resin such as melamine or phenol onto a metal member or a ceramic member.

FIG. 3 shows the shape of the spirally grooved ceramic cylinders 5 to 1.0. The shape of the spiral groove 22 formed on the outer periphery of the cylindrical body 5 is determined by the processing material and extrusion conditions, but the spiral groove 22 is made to be continuous when a plurality of cylindrical bodies are connected. In the example shown in FIG. 1, the groove 22 gradually becomes deeper in the direction of 10 along the screw 1, but the groove 22 is not limited thereto.

The ceramic cylinders 5 to 10 are elongated along the central axis in order to be coupled to the metal shaft 21.

When the cylindrical bodies 5 to 10 are bonded to the shaft body 21, a completely circular hole may be used, but when the cylindrical bodies 5 to 10 are removably attached, the holes a and b in FIG.

As shown in C, it is necessary to provide a keyway or modify the shape of the hole to stop the rotation between the cylindrical bodies 5 to 10 and the shaft body 21.

Even when the member 18 is produced independently of the shaft body 21, its shape can follow the shape shown in FIG.

The materials for the spiral grooved ceramic cylinders 5 to 10 include:
A sintered body of alumina, zirconia, silicon nitride, etc., which has high wear resistance and heat resistance, is used.

In particular, the content of alumina is 80% by weight or more, especially 85% to 85% by weight.
A 95% by weight sintered body is preferable because it has excellent wear resistance, impact resistance, heat resistance, and moldability.

The ceramic cylindrical body 3 may be manufactured by forming and firing according to a conventional method. The raw material powder preferably has a rough diameter of 5 μm or less, particularly about 1 to 3 μm, in order to improve the surface precision after firing. When molding, the dimensions and shape are set in consideration of shrinkage after firing, but if necessary, after firing, the dimensional accuracy is improved by grinding.

FIG. 4 shows the metal bearing 21 and the tip holding member 17. The shaft body 21 should have a necessary and sufficient thickness to withstand the maximum torsional stress applied to the screw during processing. The tip holding member 17 is manufactured by machining, but when making a screw connection with the shaft body 21, a method such as making the screw rotate in the opposite direction is used.

FIG. 5 explains a method of fixing ceramic parts when the screw is to be made of ceramic parts up to the tip of the screw. Cylindrical body 23
, 25 are fixed to the shaft body 26.

FIG. 6 shows an alternative screw, which uses a ceramic cylinder 27 with specially shaped grooves near the tip to enhance the mixing effect. As described above, since the screw according to the present invention uses ceramic parts that can be divided and replaced, it is possible to construct a screw having a desired tooth profile by appropriately combining ceramic parts having spiral grooves of various shapes. is possible.

FIG. 7 shows examples of ceramic barrel lining members 11, 12, 13, 14, 15, and 16. These lining members 11 to 16 are generally tubular, but in order to fix them to the barrel body without rotation, for example, as shown in FIG. 7(A), flanges 28 are formed at both ends. Groove 29 on 28
or as shown in FIG. 7 (b), the lining member 1
The cross-sectional shapes of Nos. 1 to 16 are modified. Further, if a vent is required, vent holes 30 are provided in the ceramic lining members (11 to 16) as shown in FIG. 7(c).

The material composition and manufacturing method of these ceramic lining members 11-16 are the same as those of the ceramic cylindrical bodies 5-10. Further, it is preferable to provide a buffer band as described above between these ceramic lining members 11 to 16 and the main body of the metal barrel 2, or between the ceramic lining members 11 to 16 as well.

FIG. 8 shows an example of the structure of a screw for a kneader.

This screw passes a metal shaft 33 through ceramic cylinders 31 and 32 having spiral grooves on the outer periphery, and is fixed at both ends with holding members 34 and 35. The helical grooves of the kneader screws are generally deeper than the grooves of the extruder, but the production and assembly of the ceramic cylinders 31, 32 are similar to those of the extruder. Figure 9 shows two screws like this.
6 is a cross-sectional view showing a twin-screw kneader configured with parts 6 and 37.

The container 38 of this twin-screw kneader has a ceramic lining 39 on its inner surface. Note that the configuration of the crosstalk machine can be configured with one shaft, two shafts, or three or more shafts according to a conventional method.

〔Example〕

±-Based on the above-mentioned conventional melt extruder having mixing, metering, melting, compression, and thrust zones, a melt extruder was created in which the screw and part of the barrel were made of ceramic, as shown in Figure 1. .

First, the screw has a total length of 2000 mm as shown in Figure 2.
In order to ceramicize the central 1680+u length of the 1680mm spiral groove, that is, from the metering zone to the melting zone and the compression zone, six spirally grooved alumina cylindrical bodies with a length of 280mm as shown in Fig. 3 were created. .

To create an alumina cylinder, 100 parts by weight of alumina powder (purity 92% by weight) with a particle size of 3 μm or less, 65 to 70 parts by weight of water,
Parts by weight, and 2 to 6 parts by weight of P, V, A, were thoroughly mixed and made into granules with a spray dryer, and the outer diameter was 771.
A hollow cylindrical body having an inner diameter of 45 mm and a keyway of 333 mm in length was made into a hollow cylindrical body, which was then cut and processed into the shape shown in FIG. 3a. The spiral groove of each cylinder has a pitch length (
74.7mm) and the shape of the peaks were the same, the depth of the valleys was increased sequentially to L (from 8.1mm to 20.7mm), and this molded body was fired at 1650°C for 1 hour.

Further, for the ceramic barrel lining, six alumina tubes having a shape as shown in FIG. 7(a) were prepared.

The material composition and manufacturing method of this alumina tube are the same as those of the alumina cylinder. The alumina tube body had an inner diameter of 65 mm, an outer diameter of 85 m, and a length of 280 mm, and had flanges with an outer diameter of 105 mm and a thickness of about 12 m at both ends, and four grooves were formed in the flanges.

A shaft body and a tip holding member as shown in FIG. 4, and a spirally grooved cylindrical body (propelling section) as shown in FIG. 1 were fabricated by machining steel materials. The shaft body has a cylindrical insertion part with an outer diameter of 38 m.
The length was 2000 mm, and the tip was threaded and the cylindrical body insertion part was machined with a keyway. At the rear of the shaft, a stopper having an outer diameter approximately the same as the inner diameter of the barrel to stop the backward movement of the processed material and a connecting portion with a drive device (not shown) were formed. The surfaces of the shaft body, tip presser member, and cylindrical body thus processed were plated with hard chrome.

The barrel body is basically the same as the regular type, and the inner surface from the alkali and metering body to the melt and compression zone has been processed to accommodate an alumina lining.

When assembling the screw and barrel, a 0.2-inch thick polyimide film was inserted between the ceramic parts and the steel parts and between the ceramic parts to serve as a buffer zone.

In this way, a melt extruder was finally completed.

Using this melt extruder, we melt-extruded a composite material containing short glass fibers and a polyolefin polymer containing 30% by weight and 20% by weight of titanium oxide, respectively. There is almost no wear inside the barrel and it has withstood more than a year of use.

In contrast, conventional extruders that use steel screws and barrel inner surfaces with hard chrome plating,
When melt extruding a composite material under the same conditions as above, the mixing condition of the product deteriorates due to wear on part of the screw and the inner surface of the barrel after 24 hours of continuous operation, and the extrusion rate decreases to less than 80% and it is used within 3 weeks. becomes impossible.

Note that it is easy to disassemble the barrel body and screw and replace the ceramic lining and cylindrical body.

A melt extruder similar to that of Example 1 was constructed. However, in this melt extruder, the spiral groove of the screw has a total length of 2
It is 190m long and has an outer diameter (maximum diameter) of 65 cranes. Six alumina blocks and two zirconia blocks with a length of 250 mm were prepared as ceramic cylinders with spiral grooves.

These cylindrical bodies were fixed to a steel shaft body plated with nickel and zirconia at the tip of the screw. In this shaft as well, a hard nickel-plated steel member having a spiral groove on the outer periphery was used for the propulsion portion and the tip portion.

Three tubes made of alumina and two tubes made of silicon nitride, each having a length of 2501 mm and an inner diameter of 650 mm and flanges at both ends, were prepared as the inner lining of the barrel. When assembling the barrel, from the measuring section to the melting section and the compression section, there are 3 alumina barrel linings (750 mm) and 2 silicon nitride barrel linings.
pieces (500m), 75 parts without ceramic lining
Composed of 0 cranes. Additionally, three vents were formed near the tip of the barrel.

The inside of the aperture gate at the extrusion tip is made of zirconia,
A tip gate was created by protecting the outside with a steel member.

Using this melt extruder, a crosslinkable polyether containing 60% by weight of a mixture of whiskers and inorganic fine particles such as titanium oxide, magnesium silicate, and aluminium oxide was integrally melt-extruded. Even after continuous operation for 6 months, it can be operated well without any change in appearance, extrusion pressure, or other measurements.

On the other hand, when the above composite material is melt-extruded under the same conditions using a melt-extruder made of hard nickel-plated steel of the same shape, the wear becomes significant after about a week, and the screws must be thickened once a week. It was necessary to scrunch the barrel once a month.

5 - A screw for a kneader was prepared in the same manner as the screw in Main Example 1. The shape of this screw is as shown in Figure 8, and the effective length of the helical groove is 600 m, the depth of the groove is deeper than that of an extruder screw (about 22 mm), and the groove is deep along the axis of the screw. The depth of the groove does not change. Two spirally grooved alumina cylinders each having a length of 250 fi were used to form one screw.

Using this alumina screw, as shown in Figure 9 (
, a two-screw kneader was constructed. An alumina lining was placed on the inner surface of the container of this crosstalk machine.

This kneader was used to heat and knead ABS resin containing 50% by weight of magnesium silicate, zinc oxide, glass fiber, and stabilizer, and was used to produce a premix intermediate product. As a result, the replacement life of the mixing screw is 10% longer than when using conventional hard nickel-plated steel screws.
It was extended 2 to 15 times.

In addition, in the case of a kneader, the surface finish accuracy did not necessarily need to be high, and it was sufficient to simply improve the dimensional accuracy before firing.

〔Effect of the invention〕

The present invention provides an extruder and a kneader that have improved wear resistance and heat resistance and are suitable for processing hard materials or materials containing hard materials.

In explaining the present invention, reference has been made mainly to the processing of composite materials in which hard materials are blended into resin. However, the characteristics that wear resistance and heat resistance are improved by using ceramic members are It is clear that it is also effective in processing such as.

[Brief explanation of drawings]

Fig. 1 is a schematic diagram of an extruder according to the present invention, Fig. 2 is a partially sectional front view of a screw of the extruder, Fig. 3 is a front view and side view of a ceramic cylinder with a spiral groove, and Fig. 4. 5 is a sectional view showing another embodiment of the screw and a method of assembling the tip, FIG. 6 is a sectional view showing still another embodiment of the screw, and FIG. ) ~
(c) is a cross-sectional view and side view of the ceramic barrel lining;
FIG. 8 is a front view of the screw of the mixer according to the present invention, and FIG. 9 is a schematic sectional view of the two-screw mixer according to the present invention. 1...screw, 2...barrel, 3...
・Hopper, 4...Aperture gate section, 5-1
0... Ceramic cylindrical body with spiral grooves, 11-16...
- Ceramic barrel lining, 17... Metal cylindrical body member with spiral groove, 18... Metal cylindrical body with spiral groove, 19... Stopper, 21... Metal shaft, 2
2... Spiral groove, 23, 25... Ceramic cylinder with spiral groove at tip, 27... Ceramic cylinder with spiral groove, 28...
- Flange part, 29... Key groove, 30... Vent hole, 31, 32... Ceramic cylindrical body with spiral groove, 33
...metal shaft body, 34, 35...pressing member,
38... Container, 39... Ceramic lining. No. 71gl Procedural Amendment (Voluntary) 1985 Calling Form 2+ Day

Claims (1)

[Claims] 1. In an extruder or kneader that extrudes or kneads a material to be processed using a screw that rotates inside a container, a part or all of the outer surface of the screw that is in contact with the material to be processed, and an inner surface of the container that is in contact with the material to be processed 1. A screw extruder or kneader, characterized in that a part or all of its surface is made of ceramic parts.