JP2000313008A - Die for extrusion molding, extrusion molding apparatus using the die, and production of molded body - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a die for extrusion molding by which extrusion velocity becomes const. and dimensional accuracy of a molded body is improved, an extrusion molding apparatus using the die, and a method for producing the molded body. SOLUTION: A die 1 wherein an extrusion hole 3 is constituted of an approximately funnel-shaped crosssection changing successively from a large diameter hole to a small diameter along the extrusion direction and the length of the hole at the smallest diameter is 15-200% to the diameter at the smallest diameter part is provided. This extrusion molding apparatus is provided with the die 1 and a cutting device 2 which cuts the molded article just after extrusion by crossing the front face of an extrusion hole 3 of the die 1 while it is brought into contact with the peripheral edge of the extrusion hole 3.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

TECHNICAL FIELD The present invention relates to an extrusion die,
The present invention relates to an extrusion molding apparatus and a method for producing a molded body using the same.

[Prior art]

Generally, a catalyst, a catalyst carrier, an adsorbent, a drying material, a humidity control material and the like have a diameter of 2 to 10 mm and a length of 10 to 20 m.
It is formed into a cylindrical or cylindrical shaped body of about m, which is filled in a reactor and used for various chemical reaction processes. In order to produce such a molded article such as a catalyst, an extrusion molding method has conventionally been employed. That is, a molded product obtained by continuously extruding a soft clay-like material such as alumina from a die is cut into small pieces to produce a molded article. At this time, if the length of the molded body is not uniform, a drift or the like occurs when a fluid is passed through a reactor obtained by filling the molded body, which causes a problem in that the chemical reaction process is hindered.

[0003] For this reason, a molded product is required to have high dimensional accuracy, and a molded product extruded from an extrusion hole of a die must be extruded at a constant flow speed. For the same reason, the extruded molded body should not be bent or warped. However, conventional extrusion molding cannot perform extrusion molding with high dimensional accuracy and without deformation.

[0004]

SUMMARY OF THE INVENTION It is an object of the present invention to provide an extrusion die for obtaining a molded body having improved dimensional accuracy, an extrusion molding apparatus using the die, and a method of manufacturing the molded body.

[0005]

According to the present invention, there is provided an extrusion die having an extrusion hole through which a molded product is continuously extruded. The diameter of the hole at the minimum diameter is 15 to 200% with respect to the diameter of the minimum diameter portion. This prevents fluctuations in the extrusion flow, makes the extrusion speed constant, and improves the dimensional accuracy of the molded body.

The die according to the present invention is constituted by a disk attached to the tip of a cylindrical cylinder, and a conical body whose axis coincides with the center C of the disk is protruded from the back of the die. When the radius from the center C of the disk to the inner surface of the cylinder is R ₁ and the radius of the base of the cone is R ₂ , the same center C
Therefore, a plurality of extrusion holes having a center D at a position of a radius r represented by the following formula (I) are preferably arranged concentrically. r = {(R ₁ ² + R ₂ ² ) / 2} ^0.5 (I) Accordingly, it is possible to prevent the molded body extruded from the die from being warped or bent.

The extrusion molding apparatus of the present invention includes the extrusion die described above, and a cutting device for cutting a molded product immediately after extrusion by crossing the front surface of the extrusion hole while contacting the periphery of the extrusion hole. It is characterized by the following. Further, the method of manufacturing a molded article according to the present invention is characterized in that molded articles continuously extruded from the die are sequentially cut to a predetermined length by a cutting device using the above-mentioned die for extrusion molding.

[0008]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS One embodiment of the present invention is shown in FIGS.
Shown in FIG. 1 shows an extrusion molding apparatus according to this embodiment. A cutting apparatus 2 is provided on the front surface of an extrusion die 1. The die 1 has an extrusion hole 3 through which a molded product is continuously extruded. Further, the cutting device 2 has a piano wire 6 (wire material) stretched between the two guide rollers 4 and 5. The piano wire 6 moves on the front surface of the extrusion hole 3 while being in contact with the top surface of the bulging portion 15 having the trapezoidal cross section provided with the extrusion hole 3, and cuts the molded product extruded from the die 1 into a predetermined length. Thus, a molded body 7 is obtained.

The extrusion hole 3 of the die 1 is, as shown in FIG.
It has a substantially funnel-shaped cross section in which the diameter gradually decreases from the large-diameter hole 16 along the extrusion direction (indicated by the arrow A), and the length t of the hole at the minimum diameter 17 (hereinafter, simply referred to as the wall thickness t). 15 to 200%, preferably 25 to 1, of the diameter of the minimum diameter portion 17
00%. The diameter of the minimum diameter portion 17 is usually 1 to 10 m.
m, preferably 3 to 6 mm. As a specific example of the thickness t, when the diameter of the minimum diameter portion 17 is 5 mm, 0.75 to 1
0 mm, preferably 1.25 to 5 mm.

By using the extrusion hole 3 having a substantially funnel-shaped cross-section and having a reduced thickness, the fluctuation of the extrusion flow is reduced, the extrusion speed is made constant, and the size of the molding 7 is reduced. The accuracy is improved. When the wall thickness t is larger than the above range, the extrusion speed is not constant, and the length variation of the obtained molded body 7 becomes large. On the other hand, when the thickness t is smaller than the above range, the rigidity of the die 1 itself is reduced, and the dimensional accuracy such as the length and diameter of the obtained molded body is reduced.

Next, the position of the extrusion hole 3 will be described with reference to FIGS. As shown in FIG. 3, the die 1 is composed of a disk 19 attached to the tip of a cylindrical cylinder 18, and a plurality of extrusion holes 3 having a center D at a position of a radius r from the center C of the disk 19 are formed. They are arranged concentrically (see FIG. 4). Further, a cone 20 whose axis coincides with the center C of the disk is protruded from the back of the die 1. The cone 20 is configured so that the extruded material flows evenly toward each extrusion hole 3. Although the cone 20 is formed integrally with the die 1 in FIG. 3, it may be formed separately.

Here, the radius r is equal to the center C of the disk 19.
The radius from the inner surface of the cylinder 18 to R ₁ , the cone 20
Where R ₂ is the radius of the base of
It is preferable to have the relationship represented by (I) in order to prevent the molded product extruded from the die from being warped or bent. Formula (I), the extrusion hole 3 on the circumference of a circle of radius r which divides the area of the donut-like portion from the radius R ₁ of the area of a circle A1 except the area A2 of the circle of radius R ₂ equal parts It means to provide. That is, the formula _{^{(I): 2 × (πr 2 -πR 1}} 2) = calculated from ^{_{πR 1 2 -πR 2 2 (II}} ).

The radius r is expressed by the following equation (I): ｛(R ₁ ²
+ R _{² 2)} / _2} is greater than ^0.5 will tend to bend the radial direction of the first outward (outer circumferential direction). on the other hand,
When the radius r is smaller than {(R ₁ ² + R ₂ ² ) / 2} ^0.5 , the molded article tends to bend inward (in the center direction) in the radial direction of the die 1.

The die 1 shown in FIGS. 1 to 4 is for molding a columnar molded body 7, but using the die 1 provided with a core 21 as shown in FIG. A cylindrical molded body 7 'may be obtained. The core 21 includes a pin 22 and a support bar 23. Support bar 23
Both ends are bridged in the large-diameter hole 16 of the die 1, and a pin 22 is movably attached to the center of the support bar 23. When the pin 22 moves, the pin 22 is always positioned at the center with respect to the flow direction of the molded product due to the extrusion flow of the molded product, and the cylindrical molded body 7 ′ having the cavity 26 at the central portion. Can be obtained. As a specific example of the core 21, for example, as shown in FIG.
2 in addition to a support bar 23 having a pin insertion hole 24 at the center larger than the outer diameter of the pin 2 and a pin 22 having a head 25 at the rear end to be locked on the periphery of the pin insertion hole 24, and the support bar and the pin are connected by a ball joint. A connected core (not shown) and the like are included. The number of holes of the extrusion holes 3 may be appropriately determined in consideration of the outer diameter of the die 1, the inner diameter of the extrusion holes 3, and the like, and examples thereof include two, four, eight, sixteen, and thirty-two. .

Next, the cutting device 2 used in this embodiment will be described. As shown in FIG. 1, the cutting device 2 includes a disk-shaped mounting plate 9 that is integrally mounted on a rotating shaft 8 arranged parallel to the extrusion direction and perpendicular to the rotating shaft 8. 9 is arranged so as to be spaced apart from the outer surface of the die 1 and to rotate in the direction perpendicular to the extrusion direction of the molded product by rotating the rotating shaft 8.

On the front surface of the mounting plate 9 facing the die 1,
The guide rollers 4 and 5 are provided upright, and a feed-out roller 10 and a take-up roller 11 are mounted on the back surface of the mounting plate 9. The piano wire 6 is wound around a feeding roller 10 in advance, and is stretched from the feeding roller 10 to a winding roller 11 via guide rollers 4 and 5. The mounting plate 9 includes
Openings 13 and 14 for moving the piano wire 6 are provided.

The take-up roller 11 is provided with a motor 12 (rotation drive means) for winding the piano wire 6. The motor 12 is driven to take up the piano wire 6 by the take-up roller 11. Can be moved continuously. On the other hand, in order to apply a predetermined tension (tension) to the piano wire 6 to be wound, a permahist torque controller (trade name, manufactured by Ogura Clutch Co., Ltd.) is provided between the feeding roller 10 and the support plate 20 thereof. A rotation resistance means (not shown) such as a perma torque (trade name, manufactured by Kousin Seiko Co., Ltd.) is provided. The tension of the piano wire 6 can be adjusted by the rotation resistance means. The tension is usually 0.1 to 1 kgf, preferably 0.25 to 0.1 kgf.
It is good to be about 5 kgf.

The rotation shaft 8 is supported at its rear portion by a rotation drive unit (not shown) so as to be rotatable about the axis B.
It is provided coaxially with the center axis of the disk-shaped die 1. As shown in FIG. 6, a plurality of extrusion holes 3 are arranged concentrically in the die 1, so that the rotation shaft 8 is rotated and the mounting plate 9 is rotated, so that the die 1 is stretched on the front surface thereof. The passed piano wire 6 passes while crossing the front surface of each extrusion hole 3. As shown in FIG. 6, in this embodiment, two piano wires 6, 6 are stretched on the mounting plate 9 in opposite directions via the rotating shaft 8.
At 6, the molded product is cut.

The piano wire 6 used has a diameter of 200 μm.
It is preferred to use: If the diameter of the piano wire 6 is larger than 200 μm, the obtained molded body may be crushed at the cut portion. The length of the piano wire is preferably about 150 to 10 m. If the length of the piano wire exceeds 150 m, the piano wire 6 may be bent at the time of winding around the feeding roller 10. On the other hand, if the length of the piano wire is less than 10 m, the piano wire 6 must be replaced frequently, and the productivity is reduced. The winding speed of the piano wire 6 is not particularly limited.
It can be appropriately set in consideration of the extrusion speed of the molded article from the die 1, the number of extrusion holes 3 in the die 1, and the like.
mm / min.

In this embodiment, the piano wire 6 is connected to the extrusion hole 3
Is moved while being in contact with the top surface of the bulging portion 15 having a trapezoidal cross section provided with the above. However, since the piano wire 6 is moved while being continuously wound as described above, the piano wire 6 does not break. . Therefore, the extruder can be continuously operated until the piano wire 6 wound around the pay-out roller 10 is almost completely wound up, and the trouble of frequently changing the piano wire 6 is greatly reduced. The productivity and workability are improved, the product yield is improved, and the process can be prevented from being stopped by cutting the piano wire 6, so that the process management is facilitated.

The cutting device is not limited to the above-mentioned cutting device using a piano wire, but may be another metal wire or a cutting device using a wire made of a plastic material or a fiber material. Further, the present invention can be applied to a cutting device using a blade or the like as long as the effects of the present invention are not impaired.
Further, in the above embodiment, the mounting plate 9 is configured to rotate, but may be reciprocated in a direction orthogonal to the extrusion direction of the molded product.

Specific examples of the molded body include, for example, a catalyst, a catalyst carrier, an adsorbent, a drying material, a humidity control material and the like. Further, the material of the molded body is not limited to the inorganic material, and the die and the extrusion molding apparatus of the present invention can be applied to various plastic materials and the like.

[0023]

EXAMPLES The extrusion molding apparatus of the present invention will be described below with reference to examples and comparative examples. Examples and Comparative Examples Clay-like alumina catalyst molded bodies were extruded with various dies 1 having different thicknesses t shown in FIG. 2 using the extrusion molding apparatus shown in FIGS. The dies 1 used were all chrome-plated on the surface, and the extruded holes 3 were concentrically formed by 8 holes.
It has the shape of a disc arranged. The extrusion hole 3 has a minimum diameter portion 17
Is 5 mm and has a center at a radius of 60 mm from the same center for a cylinder radius of 80 mm. The thickness t of each die 1 used is 1.5 mm, 3 mm, respectively.
6.2 mm and 20 mm. The thickness t is 6.2.
The mm die is a die for manufacturing a cylindrically formed body 7 'having a core 21 as shown in FIG. Cutting device 2
Is a tension of 0.5 kgf (at the start of molding) to 0.25 kgf using a piano wire 6 having a diameter of 150 μm and a length of 100 m.
(At the end of molding), the piano wire 6 was continuously moved at a winding speed of 25 mm / min, and was moved while being in contact with the top surface of the bulging portion 15 provided with the extrusion hole 3. These dies 1
Using the cutting apparatus 2, the alumina catalyst molded body was extruded at an extrusion speed of 40 mm / min. as a result,
The continuous operation of the piano wire 6 for 8 hours and 57 minutes was possible without cutting.

On the other hand, the effect of the thickness t of the die 1 on the dimensional accuracy of the compact was evaluated by the coefficient of variation of the length of the compact (the number of samples n = 10). Here, the length variation coefficient (%) refers to the measurement of the length of each sample, and the formula: (standard deviation / average value) × 1
It is calculated from 00, and indicates that a large length variation coefficient indicates large dimensional variation. The molded body to be filled in the reactor is required to have a length variation coefficient of 10% or less for the purpose of keeping the packing density constant and making the flow uniform. FIG. 7 shows the results. As is apparent from FIG. 7, in order to reduce the length variation coefficient to 10% or less,
It is understood that the thickness t of the die 1 is desirably set to 10 mm or less.

[0025]

According to the present invention, the extrusion hole of the die is formed in a substantially funnel-shaped cross section in which the diameter gradually decreases from the large diameter hole in the extrusion direction, and the length of the hole at the minimum diameter is the minimum diameter. Since the diameter is 15% to 200% with respect to the diameter of the part, there is an effect that the fluctuation of the extrusion flow is prevented, the extrusion speed is constant, and the dimensional accuracy of the molded body is improved. In the present invention,
The die is constituted by a disk attached to the tip of a cylindrical cylinder, and a plurality of extrusion holes having a center D at a position of a radius r represented by the above formula (I) from the center C of the disk are formed concentrically. By arranging, there is an effect that it is possible to prevent the molded body extruded from the die from being warped or bent.

[0026]

[Brief description of the drawings]

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

FIG. 2 is a schematic sectional view showing an extrusion hole of a die.

FIG. 3 is a sectional view showing a state where a die is attached to a cylinder.

FIG. 4 is a schematic plan view of the die shown in FIG.

FIG. 5 is a schematic cross-sectional view showing an extrusion hole of a die for producing a cylindrical formed body.

FIG. 6 is a schematic explanatory view showing a relationship between a cutting wire and an extrusion hole of a die.

FIG. 7 is a graph showing a relationship between a die thickness and a length variation coefficient.

[Description of Signs] 1 Die 2 Cutting device 3 Extrusion hole 6 Piano wire (wire material) 7 Molded body 8 Rotation axis 20 Conical body

Claims (4)

[Claims] 1. An extrusion die having an extrusion hole through which a molded product is continuously extruded, wherein the extrusion hole has a substantially funnel-shaped cross section in which the diameter decreases gradually from a large-diameter hole in an extrusion direction. An extrusion die, wherein the length of the hole at the minimum diameter is 15 to 200% of the diameter of the minimum diameter portion. 2. A circular cylinder attached to the tip of a cylindrical cylinder, and a conical body whose axis coincides with the center C of the disk protrudes from the back, and the center C of the disk is provided. When the radius from the cylinder to the inner surface of the cylinder is R ₁ , and the radius of the base of the cone is R ₂ , a plurality of extrusion holes having a center D at the position of a radius r represented by the following formula (I) from the same center C are formed. The extrusion die according to claim 1, which is arranged concentrically. ^{_{r = {(R 1 2 +}} R 2 2) / 2} 0.5 (I) 3. A die for extrusion molding according to claim 1 or 2, and a cutting device for cutting a molded product immediately after extrusion by traversing the front surface of an extrusion hole provided in the die while contacting the periphery of the extrusion hole. An extrusion molding device comprising: 4. A method of manufacturing a molded product, comprising: using a die for extrusion molding according to claim 1 or 2, and sequentially cutting a molded product extruded from the die into a predetermined length by a cutting device. Method.