WO2013137346A1

WO2013137346A1 - Extrusion-molding device and method for producing molded article using same

Info

Publication number: WO2013137346A1
Application number: PCT/JP2013/057077
Authority: WO
Inventors: 照夫小森; 和也土本; 朝吉野
Original assignee: 住友化学株式会社
Priority date: 2012-03-16
Filing date: 2013-03-13
Publication date: 2013-09-19
Also published as: JP2013193278A

Abstract

This extrusion-molding device is provided with: a channel for conveying a starting-material composition in the form of a paste; a screw for mixing the starting-material composition and conveying the same downstream, and positioned on the upstream-side of the channel; a die from which a molded article comprising the starting-material composition is extruded, and positioned on the downstream-side of the channel; a rectifier having a plurality of openings penetrating in the thickness direction thereof, and positioned between the screw and the die; a resistance tube for connecting the downstream-side of the rectifier and the die; a plurality of resistance pins which each have individually adjustable lengths projecting into the inside of the resistance tube, and positioned so as to penetrate the tube wall of the resistance tube; and a means for adjusting the temperature of the plurality of resistance pins.

Description

Extrusion molding apparatus and method for producing molded body using the same

The present invention relates to a manufacturing technique of a molded body, and more particularly to an extrusion molding apparatus for manufacturing a ceramic molded body and a manufacturing method of a molded body using the same.

Conventionally, honeycomb filter structures have been widely known for use in diesel particulate filters. This honeycomb filter structure has a structure in which one end side of some through holes of a honeycomb structure having a large number of through holes is sealed with a sealing material, and the other end side of the remaining through holes is sealed with a sealing material. Patent Documents 1 and 2 disclose a die and an extrusion molding apparatus used for manufacturing a honeycomb structure.

Japanese Patent Laid-Open No. 61-5915 Japanese Patent No. 4099896

Incidentally, a honeycomb filter structure for a diesel particle filter is generally used in a state of being housed in a rigid case. If the dimensional accuracy of the honeycomb filter structure is low, problems such as cracks in the honeycomb filter structure due to thermal stress or the like are likely to occur. Therefore, high dimensional accuracy is required for the green molded body before firing. In addition, some honeycomb structures have a narrow cell pitch (for example, about 1.1 to 2.8 mm), and high dimensional accuracy is required for the thickness of partition walls that define a large number of through holes.

When manufacturing a green molded body with an extrusion molding device, the flow rate of the raw material composition reaching the upstream surface of the die is uneven and the flow rate of the raw material composition in a specific region is high compared to other regions. The formed body is extruded from the die. If this is to be corrected straight afterwards, there arises a problem that the partition walls of the molded body are curved or cracks are formed on the outer surface. Further, even if a straight product is obtained at the initial stage when the production of the molded body is started, the bending of the molded body may become gradually noticeable due to die wear or the like.

The present invention has been made in view of the above problems, and provides an extrusion molding apparatus capable of efficiently producing a molded body with sufficiently small bending and high dimensional accuracy, and a method for producing a molded body using the same. With the goal.

The extrusion molding apparatus according to the present invention includes a flow path for transferring a paste-like raw material composition, a screw provided on the upstream side of the flow path, kneading the raw material composition and transferring it downstream, and a flow path A die provided on the downstream side from which a molded body made of the raw material composition is extruded, a rectifying plate provided between the screw and the die and having a plurality of openings penetrating in the thickness direction, and a downstream side of the rectifying plate and the die A resistance tube that communicates with the resistance tube, a plurality of resistance pins that are provided so as to penetrate through the tube wall of the resistance tube, and the lengths that protrude inside the resistance tube can be changed, respectively, and a means for adjusting the temperature of the plurality of resistance pins Is provided.

The plurality of resistance pins provided in the extrusion molding apparatus of the present invention is for uniformizing the flow velocity distribution of the raw material composition introduced into the die. Check the degree and direction of bending of the extruded product, and if bending exceeding the required accuracy is recognized, adjusting the protruding length of each resistance pin makes the bending sufficiently small and the dimensional accuracy is high. A molded object can be manufactured efficiently.

The plurality of resistance pins are configured so that the temperature can be adjusted. By adjusting the temperature of the resistance pin, when adjusting the protruding length of the resistance pin, the friction between the resistance pin and the paste-like raw material composition can be reduced to perform the operation smoothly. Specific examples of the means for adjusting the temperature of the resistance pin include a cooling medium circulation jacket, an electric cooler, an electric heater, or a combination thereof.

The present invention is a method for producing a molded body using the above extrusion molding apparatus, and provides a method comprising a step of changing the protruding length of a resistance pin whose temperature is adjusted. The method may further comprise the step of changing the temperature of the resistance pin. According to the method of the present invention, by appropriately adjusting the protruding length of the resistance pin, it is possible to efficiently produce a molded body with sufficiently small bending and high dimensional accuracy. By adjusting the temperature of the resistance pin to a suitable range, the friction between the resistance pin and the paste-like raw material composition can be reduced when adjusting the protruding length of the resistance pin, and the operation can be performed smoothly. it can.

According to the present invention, it is possible to efficiently produce a molded body with sufficiently small bending and high dimensional accuracy.

(A) is a perspective view which shows an example of the green molded object for honeycomb structures, (b) is the elements on larger scale of a green molded object. It is a schematic sectional drawing which shows embodiment of the extrusion molding apparatus which concerns on this invention. It is a fragmentary sectional view which shows the structure of the resistance pin provided so that the resistance tube shown in FIG. 1 and its tube wall might be penetrated. It is a figure which shows the structure of a baffle plate. It is sectional drawing which shows a mode that the front end side of a some resistance pin has protruded inside the resistance tube. It is sectional drawing which shows a mode that the front end side of a some resistance pin has protruded inside the resistance tube. It is sectional drawing which shows typically the structure inside a resistance pin. It is other embodiment of the extrusion molding apparatus which concerns on this invention, and is a fragmentary sectional view which shows the form provided with the extension pipe (straight pipe part) in the downstream of the resistance pipe. It is a block diagram which shows the form provided with the mechanism which is other embodiment of the extrusion molding apparatus which concerns on this invention, and automatically controls the protrusion length of a resistance pin. It is a schematic diagram which shows an example of the mechanism which detects the bending of a molded object with a non-contact-type dimension measuring device. It is a schematic diagram which shows an example of the mechanism which detects the bending of a molded object with a non-contact-type displacement sensor. It is a figure which shows the other example of a green molded object.

Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the drawings. First, prior to description of the extrusion molding apparatus according to the present invention, a green molded body for a honeycomb structure will be described.

<Green molded body>
A green molded body 70 shown in FIG. 1 is obtained by extruding a raw material composition. As shown in FIG. 1A, the green molded body 70 is a cylindrical body in which a large number of through holes 70a are arranged substantially in parallel. The cross-sectional shape of the through hole 70a is a square as shown in FIG. The plurality of through holes 70a are arranged in a square arrangement in the green molded body 70, that is, such that the central axis of the through hole 70a is located at the apex of the square. The square size of the cross section of the through hole 70a can be set to, for example, 0.8 to 2.5 mm on a side. A honeycomb structure is manufactured by firing the green molded body 70 at a predetermined temperature.

The length of the green molded body 70 in the direction in which the through hole 70a extends is not particularly limited, and can be, for example, 40 to 350 mm. Further, the outer diameter of the green molded body 70 is not particularly limited, and can be, for example, 100 to 320 mm.

The raw material composition forming the green molded body 70 is not particularly limited, and in the case of manufacturing a honeycomb structure for a diesel particle filter, an inorganic compound source powder that is a ceramic raw material, an organic binder such as methyl cellulose, and Additives added as needed. From the viewpoint of high temperature resistance of the honeycomb structure, suitable ceramic materials include alumina, silica, mullite, cordierite, glass, oxides such as aluminum titanate, silicon carbide, silicon nitride and the like. The aluminum titanate can further contain magnesium and / or silicon.

For example, when producing a green molded body of aluminum titanate, the inorganic compound source powder includes an aluminum source powder such as α-alumina powder and a titanium source powder such as anatase type or rutile type titania powder. Furthermore, magnesium source powders such as magnesia powder and magnesia spinel powder and / or silicon source powders such as silicon oxide powder and glass frit can be included.

Examples of the organic binder include celluloses such as methylcellulose, carboxymethylcellulose, hydroxyalkylmethylcellulose, and sodium carboxymethylcellulose; alcohols such as polyvinyl alcohol; and lignin sulfonate.

Examples of additives include pore formers, lubricants and plasticizers, dispersants, and solvents.

Examples of pore-forming agents include carbon materials such as graphite; resins such as polyethylene, polypropylene, and polymethyl methacrylate; plant materials such as starch, nut shells, walnut shells, and corn; ice; and dry ice.

Lubricants and plasticizers include alcohols such as glycerol; higher fatty acids such as caprylic acid, lauric acid, palmitic acid, arachidic acid, oleic acid and stearic acid; metal stearates such as Al stearate, polyoxyalkylene alkyl And ether (POAAE).

Examples of the dispersant include inorganic acids such as nitric acid, hydrochloric acid, and sulfuric acid; organic acids such as oxalic acid, citric acid, acetic acid, malic acid, and lactic acid; alcohols such as methanol, ethanol, and propanol; ammonium polycarboxylate; Surfactants such as oxyalkylene alkyl ethers are listed.

Examples of the solvent include alcohols such as methanol, ethanol, butanol, and propanol; glycols such as propylene glycol, polypropylene glycol, and ethylene glycol; and water.

<Extrusion molding equipment>
A preferred embodiment of the extrusion molding apparatus according to the present invention will be described with reference to FIGS. The extrusion molding apparatus 10 shown in FIG. 2 is for producing a green molded body 70 from a powdery or pasty raw material composition.

The extrusion molding apparatus 10 includes a screw 2A provided at the upper stage in the housing 1 and a screw 2B provided at the lower stage. The

screws

2A and 2B are for kneading the raw material composition supplied from the inlet 1a and transferring it downstream through the flow path 1b. A vacuum chamber 3 is provided between the

screws

2A and 2B, and the raw material composition can be degassed by reducing the pressure in the vacuum chamber 3. The raw material composition in the vacuum chamber 3 is introduced into the lower screw 2B by the roller 3a.

The extrusion molding apparatus 10 includes a rectifying plate 5 provided on the downstream side of the screw 2B, a die 8 from which a molded body 70A made of a raw material composition is extruded, a resistance tube 9 that communicates the flow path 1b and the die 8, and a resistance. It further includes 16 resistance pins P which are provided so as to penetrate the tube wall of the tube 9 and whose lengths protrude inside the resistance tube 9 can be changed (see FIGS. 3 and 5). The resistance tube 9 has a tapered inner flow path, and the flow path cross-sectional area gradually decreases from the upstream side toward the downstream side. In addition, when manufacturing the molded object 70A whose diameter is larger than the diameter of the screw 2B, the resistance tube 9 may have an enlarged portion in which the flow path cross section increases from upstream to downstream. A support base 15 for supporting the molded body 70A is installed next to the extrusion molding apparatus 10 so that the molded body 70A extruded from the die 8 is not deformed. Prior to the introduction of the raw material composition into the die 8, the rectifying plate 5 and the plurality of resistance pins P are intended to make the flow velocity distribution uniform.

The rectifying plate 5 is detachably attached to the housing 1 and is disposed between the screw 2B and the die 8. 4A is a front view of the current plate 5, and FIG. 4B is a cross-sectional view of the current plate 5. The rectifying plate 5 has a plurality of openings 5a penetrating in the thickness direction. The rectifying plate 5 may have a net-like resistor (not shown) in order to enhance the effect of adjusting the flow rate. As the net-like resistor, for example, a wire net having a mesh number of 5 to 200 mesh (more preferably 50 to 150 mesh) can be used. By arranging one or a plurality of wire meshes on the upstream surface of the rectifying plate 5, a higher rectifying effect can be obtained, and foreign substances contained in the raw material composition can be removed. The number of meshes (mesh) of the metal mesh here means the number of meshes between 1 inch (25.4 mm). When selecting the mesh to be used, the first condition is that the mesh opening W is small with respect to the die opening (slit width). Good. The number of meshes N can be calculated by the following formula.
N = 25.4 / (W + d)
In the formula, W represents the mesh opening (mm), and d represents the wire diameter (mm) of the mesh.

The rectifying plate 5 is preferably a structure that hardly causes distortion even when pressure is applied from the upstream side. From this viewpoint, the material of the rectifying plate 5 is preferably carbon steel, for example. Examples of suitable materials other than carbon steel include special steels containing nickel, chromium, tungsten and the like. The thickness of the current plate 5 is preferably 10 to 100 mm from the viewpoint of ensuring sufficient strength.

The rectifying plate 5 has a plurality of openings 5a having a diameter of 1 to 10 mm penetrating in the thickness direction. The opening ratio of the rectifying plate 5 is preferably 30 to 80%. When the current plate 5 having an opening ratio of less than 30% is used, a sufficient amount of the raw material composition cannot be passed per unit time unless the upstream pressure is excessively increased, and the pressure is the allowable pressure of the apparatus. It is easy to become more. On the other hand, the current plate 5 having an aperture ratio exceeding 80% tends to have insufficient strength. The opening ratio of the rectifying plate 5 is preferably 40 to 80%, and more preferably 50 to 80%.

Here, the “aperture ratio” means a value calculated by dividing the total area of the openings on one surface of the current plate 5 by the area of the one surface (excluding the peripheral edge covered by the housing). . In addition, in the case of a rectifying plate in which the flow passage cross-sectional area of the opening is not constant, the total area of the opening may vary depending on the position of the rectifying plate in the thickness direction (feeding direction of the raw material composition). This means a value calculated using the minimum value of the sum.

The 16 resistance pins P are provided so as to penetrate the tube wall of the resistance tube 9 as shown in FIGS. 3 and 5, and are arranged at substantially equal intervals in the circumferential direction of the resistance tube 9. The length of the resistance pin P protruding inside the resistance tube 9 can be freely changed. More specifically, the resistance pin P has a seal mechanism that does not leak the raw material composition from between the resistance pin 9 and the resistance tube 9, and is slidable with respect to the resistance wall 9. Note that, as a configuration that allows the protruding length to be changed, a screw rotation type mechanism using a screw provided in the resistance pin P and a screw hole provided in the resistance tube 9 may be used instead of the slide type mechanism. Further, the number of resistance pins P is not limited to 16. However, in order to obtain a sufficient flow rate adjustment effect, it is preferably 6 to 36 per pair.

From the viewpoint of obtaining a sufficient flow rate adjustment effect, the plurality of resistance pins P are preferably arranged at predetermined positions on the upstream side of the die 8. That is, it is preferable that the central axes of the plurality of resistance pins P are installed in the range of 10 to 100 mm (more preferably 10 to 50 mm) from the upstream surface of the die 8.

The protruding length of the resistance pin P can be changed. By increasing the protruding length, the flow rate of the raw material composition flowing through the region can be reduced, and the bending of the green molded body 70 can be reduced. The protruding length can be 0 to 120% (see FIG. 6), preferably 0 to 100%, based on the radius of the position where the resistance pin P of the resistance tube 9 is provided (see FIG. 5). reference).

For example, when the extruded green molded body 70 is curved upward, it is considered that the flow rate of the raw material composition flowing in the lower region of the resistance tube 9 is higher than the other regions. In this case, as shown in FIG. 5, a plurality of resistance pins P located in the region may be projected. In FIG. 5, the ratio of the protrusion length (radius reference of the resistance tube 9) is 100% for the resistance pin P1 located at the lower end, 70% for the adjacent resistance pin P2, and further for the adjacent resistance pin. P3 is set to 30%. The green molded body 70 having sufficiently high dimensional accuracy can be continuously manufactured by checking the degree and direction of bending of the extruded molded body and changing the protruding length of each resistance pin P.

It is preferable that the tip of the resistance pin P is tapered. By adopting such a configuration, even when each resistance pin P protrudes to the center of the resistance tube 9, it is possible to sufficiently suppress the adjacent resistance pins P from interfering with each other. When all the resistance pins P are projected to the center, that is, when the ratio of the projection lengths of all the resistance pins P is 100%, the flow path at the position where the resistance pins P of the resistance tube 9 are provided. Assuming that the cross-sectional area is 100, the cross-sectional area of the flow path excluding the portion blocked by the resistance pin P is preferably about 10 to 50. Setting the ratio of the flow path cross-sectional area to less than 10 tends to complicate the mechanism of the apparatus, and if it exceeds 50, the effect of adjusting the flow velocity by the resistance pin P tends to be insufficient.

As shown in FIG. 3, the resistance pin P may be disposed so that the angle formed with the central axis of the resistance tube 9 is 90 °, or may be disposed so as to be inclined upstream or downstream. When the resistance pin P is inclined to the upstream side or the downstream side, the inclination angle of the resistance pin P is preferably within 30 ° with respect to a plane whose normal is the central axis of the resistance tube 9.

As shown in FIG. 7, the resistance pin P is hollow except for the tip portion Pa, and a tube Pc for introducing a refrigerant is inserted into the hollow portion Pb. A refrigerant (for example, an antifreeze liquid typified by cold water or an ethylene glycol aqueous solution) can be supplied from the pipe Pc to the tip of the resistance pin P. The resistance pin P is cooled by the refrigerant passing through the hollow portion Pb, and the refrigerant returns to the proximal end side of the resistance pin P. The arrows in FIG. 7 indicate the flow of the refrigerant. In addition, what is necessary is just to use a heat medium (for example, hot water, silicone oil) instead of a refrigerant | coolant, when heating the resistance pin P. In the present embodiment, the tip portion Pa, the hollow portion Pb, and the pipe Pc constitute a cooling medium circulation jacket (temperature adjusting means) Ptc. It is preferable that all of the resistance pins P (16 in the present embodiment) have the cooling medium circulation jacket Ptc.

As a means for adjusting the temperature of the resistance pin P, the cooling medium circulation jacket as described above is preferable, but instead of or together with this, an electric cooler (for example, a Peltier element), an electric heater, or these You may employ | adopt the combination of. By adjusting the temperature of the resistance pin P, the friction between the resistance pin P and the paste-like raw material composition can be reduced when adjusting the protruding length of the resistance pin P for the purpose of controlling the flow rate, and the operation is smoothly performed. Can be done.

The die 8 is for producing a molded body having the shape shown in FIG. 1 from the raw material composition, and has a grid-like flow path (not shown) corresponding thereto. A die used for manufacturing a molded body having a cell structure such as the green molded body 70 needs to set the flow path precisely and is generally expensive. For this reason, it is desirable to reduce the frequency of die replacement work as much as possible. In this embodiment, the frequency of changing the setting of the die 8 can be reduced by changing the protruding length of the resistance pin P provided on the resistance tube 9, and the length of the die 8 can be increased by uniformizing the flow rate of the raw material composition. The service life is extended and the replacement frequency can be lowered.

In the above embodiment, the case where a plurality of resistance pins P are provided on the tube wall of the resistance tube 9 is exemplified, but if the position where the plurality of resistance pins are provided is between the rectifying plate 5 and the die 8, It is not limited. For example, when an extension tube (straight tube portion) 9a is connected to the downstream side of the resistance tube (tapered portion) 9, a plurality of resistance pins P may be provided on the resistance tube 9 or the extension tube 9a (see FIG. 8). A plurality of resistance pins P may be provided on both the resistance tube 9 and the extension tube 9a.

<Method for producing green molded body>
Next, a method for manufacturing the green molded body 70 using the extrusion molding apparatus 10 will be described. First, the raw material composition is introduced into the flow path 1b from the inlet 1a. By operating the

screws

2A, 2B and the roller 3a, the raw material composition is kneaded and transferred downstream. The kneaded material is passed through the opening 5 a of the rectifying plate 5 to make the flow velocity distribution uniform, and then introduced into the die 8 through the resistance tube 9. The linear velocity of the raw material composition on the downstream side of the die 8 can be about 10 to 150 cm / min.

The raw material composition with a uniform flow velocity distribution is extruded from the die 8 and the compact 70A is collected on the support base 15. The green molded body 70 is obtained by cutting the molded body 70A into a predetermined length.

When the flow velocity distribution is not sufficiently uniformed only by the rectifying action of the rectifying plate 5 and the degree of bending of the green molded body 70 becomes remarkable, a step of changing the protruding length of the resistance pin P is performed. Prior to changing the protruding length of the resistor pin P, the temperature of the resistor pin P whose protruding length is changed is adjusted to a predetermined temperature by the temperature adjusting means Ptc. In order to perform the operation of adjusting the protruding length of the resistance pin P more smoothly, the temperature of the resistance pin P is controlled to be equal to or lower than the temperature of the housing 1 or the resistance tube 9, for example. Is preferred. More specifically, it is preferable to adjust the temperature of the resistance pin P so that it is preferably in the range of 5 to 30 ° C., more preferably in the range of 10 to 25 ° C. The temperature adjustment of the resistance pin P may be performed by manually setting the temperature or automatically.

The step of changing the protruding length of the resistance pin P whose temperature has been adjusted can be performed without stopping the supply of the raw material composition to the extrusion molding apparatus 10. As a result, the green molded body 70 with sufficiently high dimensional accuracy can be efficiently manufactured over a long period of time without changing or changing the setting of the die 8. In particular, if an extrusion molding apparatus having a mechanism for automatically controlling the protruding lengths of the plurality of resistance pins P is used, the protruding lengths of the resistance pins P can be automatically changed.

9 has the same configuration as the above-described extrusion molding apparatus 10 except that the extrusion molding apparatus 20 further includes a mechanism that automatically controls the protruding length of each of the plurality of resistance pins P. The extrusion molding device 20 is a computer 12 that detects the degree and direction of bending of the molded body 70 </ b> A extruded from the die 8, and a computer that calculates the length of the plurality of resistance pins P to be projected based on data from the sensor 12. 13 and a pin drive mechanism 14 that changes the protruding length of each of the plurality of resistance pins P based on the output from the computer 13. As the sensor 12, a non-contact type displacement sensor using a laser beam or LED light L, a non-contact type size measuring device, or the like can be used. As the pin drive mechanism 14, when the resistance pin P is a slide type or a screw rotation type, a mechanism that reciprocates or rotates the resistance pin P with a gear or the like can be adopted.

FIG. 10 is a diagram showing a configuration of a bending detection mechanism when a non-contact type dimension measuring device LS-7000 (trade name, manufactured by Keyence Corporation) is used as the sensor 12. The bending of the molded body 70A is detected by using four sets of sensors (non-contact type dimension measuring devices 12A to 12D) each including a light emitting element 12a that emits laser light or LED light L and a light receiving element 12b. A circle Y consisting of a broken line in FIG. 10 indicates the cross-sectional position of the molded body when a straight molded body 70A is obtained, and a circle N consisting of a solid line indicates the cross-sectional position of the molded body where bending has occurred. is there. Two sets of non-contact

type displacement sensors

12A and 12B may be used.

FIG. 11 is a diagram showing a configuration of a bending detection mechanism when a non-contact displacement sensor LK-G (trade name, manufactured by Keyence Corporation) is used as the sensor 12. Sixteen non-contact displacement sensors 12a to 12p are arranged so as to surround the molded body 70A. A circle Y consisting of a broken line in FIG. 11 indicates the cross-sectional position of the molded body when a straight molded body 70A is obtained, and a circle N consisting of a solid line indicates the cross-sectional position of the molded body where bending has occurred. is there. When the non-contact size measuring device is arranged as shown in FIG. 11, the number thereof is not particularly correlated with the number of resistance pins P, but is preferably larger than the number of resistance pins P. Further, only one of a pair of opposing measuring devices may be used, for example, only measuring devices 12a to 12h shown in FIG.

As mentioned above, although the suitable embodiment of the present invention was described in detail, the present invention is not limited to the above-mentioned embodiment. For example, in the above-described embodiment, the cylindrical green molded body 70 is illustrated, but the shape and structure of the molded body are not limited thereto. The outer shape of the green molded body 70 may be, for example, a rectangular column such as a quadrangular column or an elliptical column. Further, the arrangement of the through holes 70a may not be a square arrangement, and may be, for example, a substantially triangular arrangement, a substantially hexagonal arrangement, or the like. Furthermore, the shape of the through hole 70a may not be square, and may be, for example, a substantially triangular shape, a substantially hexagonal shape, a substantially octagonal shape, a substantially circular shape, or a combination thereof. Examples of the combination of a plurality of shapes include a combination of a regular hexagon and an asymmetric hexagon (see FIG. 12), a combination of a square and an octagon (octosquare), and the like.

The green honeycomb molded body 80 shown in FIG. 12 has a plurality of through

holes

81a and 81b having different cross-sectional shapes. The plurality of through

holes

81 a and 81 b are partitioned by a partition wall 82 extending substantially parallel to the central axis of the green honeycomb molded body 80. The through hole 81a has a regular hexagonal cross-sectional shape. On the other hand, the through-hole 81b has a flat hexagonal cross-sectional shape and is disposed so as to surround one through-hole 81a.

DESCRIPTION OF SYMBOLS 1 ... Housing, 1b ... Flow path, 2B ... Screw, 5 ... Current plate, 5a ... Opening, 8 ... Die, 9 ... Resistance pipe (taper part), 9a ... Extension pipe (straight pipe part) 10, 20 ... Extrusion Molding device, 12 ... sensor, 12A, 12B ... non-contact displacement sensor (sensor), 12a to 12p ... non-contact dimension measuring device (sensor), 13 ... computer, 14 ... pin drive mechanism, 70, 80 ... green molding Body, 70A ... molded body, P (P1, P2, P3) ... resistance pin, Pa ... tip, Pb ... hollow part, Pc ... pipe, Ptc ... cooling medium circulation jacket (temperature adjusting means).

Claims

A flow path for transferring a paste-like raw material composition;
A screw provided on the upstream side of the flow path, kneading the raw material composition and transferring it downstream;
A die provided on the downstream side of the flow path, from which a molded body made of the raw material composition is extruded;
A rectifying plate provided between the screw and the die and having a plurality of openings penetrating in the thickness direction;
A resistance tube communicating with the downstream side of the current plate and the die;
A plurality of resistance pins provided so as to pass through the tube wall of the resistance tube, and the length protruding inside the resistance tube can be changed respectively;
Means for adjusting the temperature of the plurality of resistance pins;
An extrusion apparatus comprising:
The apparatus according to claim 1, wherein the means for adjusting the temperature is a cooling medium circulation jacket, an electric cooler, an electric heater, or a combination thereof.
The resistance tube has a tapered portion whose flow path cross section decreases from upstream to downstream, and a straight tube portion connected to the downstream side of the tapered portion, and the plurality of resistance pins include the tapered portion and the straight portion. The apparatus of Claim 1 or 2 provided in the one or both of the pipe parts.
A sensor for detecting the degree and direction of bending of the molded body extruded from the die;
A computer for calculating a length to be projected of the plurality of resistance pins based on data from the sensor;
A pin drive mechanism for changing the protruding length of each of the plurality of resistance pins based on an output from the computer;
The apparatus according to any one of claims 1 to 3, further comprising:
A method for producing a molded body using the extrusion molding apparatus according to any one of claims 1 to 4, comprising a step of changing a protruding length of the resistance pin whose temperature is adjusted.
A method for producing a molded body using the extrusion molding apparatus according to claim 4, comprising a step of automatically changing the protruding length of the resistance pin.
The method according to claim 5 or 6, further comprising a step of changing a temperature of the resistance pin.