JP2015229316A - Extrusion molding die and production method of molding - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an extrusion molding die which suppresses occurrence of poor molding.SOLUTION: An extrusion molding die 1 is used in molding a molding 40 which has a hollow part 43 and is provided with a core part 41 and a skin part 42 covering the core part 41, by extrusion of a molding material 30. The extrusion molding die 1 includes an outer frame die 2 for forming an outer frame of the molding 40 and a hollow pin 11 for forming the hollow part 43 of the molding 40. The extrusion molding die 1 has, close to an outlet of the outer frame die 2, an expanded passage part 3 in which a passage 20 for the molding material 30 is expanded toward a drawing axis 11y of the hollow pin 11.

Description

  The present invention relates to an extrusion mold and a method for producing a molded body using the same.

  Conventionally, ceramic-type molded bodies formed by extrusion molding of materials such as cement and gypsum are known. Ceramic moldings are used as ceramic building materials. Ceramic-based building materials are used for various building materials such as outer walls of buildings. Such ceramic building materials have been proposed to be formed into various structures for the purpose of improving performances such as strength, fire resistance, heat insulation, and handleability. For example, Patent Document 1 discloses a ceramic building material having a two-layer structure. In this ceramic building material, a coating layer of high specific gravity cement is formed on the surface of a foamed lightweight cement board, which has a structure having a core part and a skin part. And the core part is wrapped in the skin part over the whole surface. In such a molded body, the molding material for forming the core part and the molding material for forming the skin part are merged inside the extrusion mold and then extruded from the extrusion mold. It is formed.

JP-A-2-14105

  In the molded body having the core part and the skin part as described above, the extruded molded body may be defective due to the difference between the molding material forming the core part and the molding material forming the skin part. It turned out to be. For example, if the molding material passes through the flow path in the extrusion mold in a compressed state, but the material forming the core portion has a higher expansibility than the material forming the skin portion, the material is removed from the extrusion mold. When it comes out, the core part may swell and spread the skin part. As a result, cracks may occur in the skin part, the skin part may be torn, or peeling may occur between the core part and the skin part, resulting in molding defects.

  An object of the present invention is to provide an extrusion mold and a method for producing a molded body that suppress the occurrence of molding defects.

  The extrusion mold according to the present invention is a mold that forms a molded body having a hollow portion and having a core portion and a skin portion covering the core portion by extruding a molding material. The extrusion mold includes an outer frame mold that forms an outer frame of the molded body and a hollow pin that forms the hollow portion of the molded body. The extrusion mold has an enlarged flow path portion in the vicinity of the outlet of the outer frame mold where the flow path of the molding material becomes larger toward the extending axis of the hollow pin.

  Preferably, the enlarged flow path section has a structure in which the cross-sectional area of the hollow pin is reduced in the vicinity of the outlet of the outer frame mold, and the tip of the hollow pin is disposed upstream of the outlet of the outer frame mold It has at least any one of the structure made.

  The manufacturing method of the molded object which concerns on this invention is a manufacturing method of the molded object which extrudes the said molding material and manufactures the said molded object using said extrusion mold. The molding material includes a skin material that forms the skin portion and a core material that forms the core portion. The skin material and the core material are merged in the extrusion mold, and the core material is expanded on the extending axis side of the hollow pin in the enlarged flow path portion, and the molding material is expanded into the extrusion mold. Take out.

  According to the present invention, since the material of the core portion expands before exiting from the outlet of the extrusion mold, the core portion is prevented from spreading the skin portion. As a result, molding defects are suppressed.

FIG. 1 consists of FIG. 1A and FIG. 1B. FIG. 1A is a partial cross-sectional view of an example of an extrusion mold. FIG. 1B is a cross-sectional view showing an example of how a molded body is manufactured using the extrusion mold of FIG. 1A. It is the schematic which shows an example of an extrusion molding apparatus. It is a perspective view which shows an example of the core of an extrusion mold. It is a perspective view which shows an example of a molded object. FIG. 5 is composed of FIGS. 5A to 5H. FIG. 5A is a partial cross-sectional view of an example of an extrusion mold. FIG. 5B is a cross-sectional view showing an example of how a molded body is manufactured using the extrusion mold shown in FIG. 5A. FIG. 5C is a partial cross-sectional view of an example of an extrusion mold. FIG. 5D is a cross-sectional view showing an example of how a molded body is manufactured using the extrusion mold of FIG. 5C. FIG. 5E is a partial cross-sectional view of an example of an extrusion mold. FIG. 5F is a cross-sectional view showing an example of how a molded body is manufactured using the extrusion mold shown in FIG. 5E. FIG. 5G is a partial cross-sectional view of an example of an extrusion mold. FIG. 5H is a cross-sectional view showing an example of how a molded body is manufactured using the extrusion mold of FIG. 5G. FIG. 6 includes FIGS. 6A to 6F. FIG. 6A is a partial cross-sectional view of an example of an extrusion mold. FIG. 6B is a cross-sectional view showing an example of how a molded body is manufactured using the extrusion mold shown in FIG. 6A. FIG. 6C is a partial cross-sectional view of an example of an extrusion mold. FIG. 6D is a cross-sectional view showing an example of how a molded body is manufactured using the extrusion mold of FIG. 6C. FIG. 6E is a partial cross-sectional view of an example of an extrusion mold. FIG. 6F is a cross-sectional view showing an example of how a molded body is manufactured using the extrusion mold of FIG. 6E. FIG. 7 is composed of FIGS. 7A to 7C. FIG. 7A is a partial cross-sectional view of a comparative example of an extrusion mold. FIG. 7B is a cross-sectional view showing an example of how a molded body is manufactured using the extrusion mold of FIG. 7A. FIG. 7C is a cross-sectional view showing an example of a molded body formed using the extrusion mold of FIG. 7A.

  The invention of the extrusion mold is disclosed as follows. FIG. 1 shows a part of an example of an extrusion mold 1. In FIG. 1A, the outline of the downstream part of the extrusion mold 1 is shown, and in FIG. 1B, the vicinity of the exit of the extrusion mold 1 when extrusion molding is performed using the extrusion mold 1 is shown. . FIG. 2 is a schematic diagram of the extrusion molding apparatus 50. The extrusion molding apparatus 50 has an extrusion mold 1. FIG. 3 is an example of the core 10 of the extrusion mold 1. FIG. 4 is an example of a molded body 40 formed by the extrusion mold 1.

  The extrusion mold 1 is a mold for forming a molded body 40 by extruding a molding material 30. In the following description, upstream and downstream are based on the direction in which the molding material 30 flows (flow direction). The flow direction is indicated by the white arrow in FIGS. 1B, 2 and 4. In FIG. 4, the thickness direction of the compact 40 is indicated by an arrow V1, and the width direction of the compact 40 is indicated by an arrow V2. The thickness direction of the molded body 40 is equal to the vertical direction of the extrusion mold 1. The width direction of the molded body 40 is equal to the width direction of the extrusion mold 1. The width direction of the extrusion mold 1 is a direction perpendicular to the flow direction and the vertical direction.

  As shown in FIG. 4, the molded body 40 includes a core portion 41 and a skin portion 42. The skin part 42 covers the core part 41. The molded body 40 has a hollow portion 43. The skin part 42 is disposed on the outer surface of the molded body 40. The skin part 42 is arrange | positioned at the surface of the molded object 40, a back surface, and a side surface. The skin part 42 may be cylindrical. The core portion 41 is disposed inside the molded body 40. The outer periphery of the core part 41 is covered with the skin part 42. The core portion 41 can be exposed on the surface of the molded body 40 when viewed from the flow direction. The hollow portion 43 may be formed inside the core portion 41. The hollow portion 43 is a cavity. The hollow portion 43 may be a rod-shaped cavity that extends in the core portion 41 along the flow direction. The molded body 40 is provided with a plurality of hollow portions 43. In the molded body 40, the skin portion 42 can be formed of a material excellent in strength and durability, and the core portion 41 can be formed of a lightweight and inexpensive material. Therefore, the performance of the molded body 40 is improved. Moreover, in the molded object 40, since the hollow part 43 exists, further weight reduction and cost reduction are achieved. Therefore, the performance of the molded body 40 is further improved.

  The molded body 40 is formed by a core material 31 for forming the core portion 41 and a skin material 32 for forming the skin portion 42. For forming the molded body 40, an extrusion molding apparatus 50 is used.

  The extrusion molding apparatus 50 in FIG. 2 is an apparatus for manufacturing the molded body 40. The extrusion molding apparatus 50 can form a ceramic-based molded body 40. The extrusion molding apparatus 50 can form a plate-shaped molded body 40. The extrusion molding apparatus 50 can preferably produce a ceramic building board. The extrusion molding apparatus 50 extrudes the molding material 30 to form the molded body 40. The molded body 40 can be a long building material along the flow direction. The extruded molded body 40 is cut at an appropriate location in the flow direction, and the dimensions are adjusted.

  As shown in FIG. 2, the extrusion molding apparatus 50 includes a first extruder 51 </ b> A and a second extruder 51 </ b> B as the extruder 51. As the first extruder 51A and the second extruder 51B, an extruder that can be used for extrusion molding of ceramic materials is used. The first extruder 51 </ b> A is a machine that extrudes the core material 31. The second extruder 51 </ b> B is a machine that extrudes the skin material 32. The extrusion molding apparatus 50 includes an extrusion mold 1 downstream of the first extruder 51A and the second extruder 51B.

  The extruder 51 includes a pug portion 52 and an auger portion 54. Here, in FIG. 2, the configuration of the first extruder 51 </ b> A is indicated by parentheses, and the configuration of the second extruder 51 </ b> B is indicated by the numbers with B added to the numbers. It is shown. For example, the pug portion 52 is indicated as a pug portion 52A in the first extruder 51A, and is indicated as a pug portion 52B in the second extruder 51B. Further, the auger part 54 is represented as an auger part 54A in the first extruder 51A, and is represented as an auger part 54B in the second extruder 51B. In FIG. 2 and the following description, the other components are also given the same reference numerals. In 1st extruder 51A and 2nd extruder 51B, what was demonstrated with the structure of only a number means that it is applicable to both.

  In the extruder 51, the pug portion 52 has a function of feeding the material downstream while kneading the material. The auger part 54 has a function of extruding a material to the extrusion mold 1. The pug portion 52 has a vacuum portion 53 at a connection position with the auger portion 54. The vacuum part 53 has a function of degassing the material. By degassing the material, the appearance of the molded body 40 is adjusted, the quality such as durability is improved, and the specific gravity is secured. In the vacuum unit 53, for example, an eye plate is provided upstream of the vacuum unit 53, and the pressure is reduced by sealing with the material itself. The extruder 51 has a material input port 55. The material input port 55 is a port through which material is input to the extruder 51. The material input port 55 is disposed upstream of the extruder 51. The material inlet 55 is connected to the pug portion 52. The extruder 51 has a material injection part 56. The material injection unit 56 is a part for injecting the material in the extruder 51 into the extrusion mold 1. The material injection unit 56 is disposed downstream of the extruder 51. The material injection part 56 is connected to the auger part 54. The pug portion 52 has a biaxial screw 57. The auger part 54 has a uniaxial screw 58. By using a screw, the material can be extruded with high uniformity. Here, the material injection part 56A of the first extruder 51A is constituted by a pipe, for example. This material injection part 56 </ b> A is connected to the core 10. The material injection part 56 </ b> B of the second extruder 51 </ b> B is connected to the outer frame mold 2. In addition, in FIG. 2, although the screw-type extruder 51 is shown, the extruder 51 may be a pump system.

  The molding material 30 includes a core material 31 for forming the core portion 41 and a skin material 32 for forming the skin portion 42. The core material 31 and the skin material 32 flow separately and merge in the extrusion mold 1. In the example of the extrusion molding apparatus 50 of FIG. 2, the core material 31 flows through the first extruder 51A. The skin material 32 flows through the second extruder 51B. Each material is charged from the material charging port 55, kneaded by the pug portion 52, degassed by the vacuum portion 53, passed through the auger portion 54, and injected from the material injection portion 56 into the extrusion mold 1. The In FIG. 2, a portion through which the core material 31 in the extrusion mold 1 passes is indicated by a broken line so that the flow of the core material 31 in the extrusion mold 1 can be easily understood. Further, the flow direction of the molding material 30 is indicated by white arrows.

  As shown in FIG. 1A, the extrusion mold 1 includes an outer frame mold 2. The outer frame mold 2 is a mold for forming the outer frame of the molded body 40. A skin material 32 flows along the outer frame mold 2. The outer frame mold 2 includes an outer frame mold upper part 2A arranged on the upper side and an outer frame mold lower part 2B arranged on the lower side. The extrusion mold 1 includes a core 10. The core 10 is disposed in a cavity inside the outer frame mold 2. The core 10 is disposed between the outer frame mold upper part 2A and the outer frame mold lower part 2B. The core 10 is fixed inside the outer frame mold 2.

  The extrusion mold 1 includes a hollow pin 11. The hollow pin 11 has a function of forming the hollow portion 43 of the molded body 40. The hollow pin 11 can be composed of a rod-shaped body. The hollow pin 11 extends in the flow direction. The extrusion mold 1 preferably has a plurality of hollow pins 11. The hollow pin 11 is preferably connected to a core body 12 which is the body of the core 10. In that case, the core 10 includes a hollow pin 11. The core body 12 does not include the hollow pin 11.

  FIG. 3 shows an example of the core 10. The core 10 has a plurality of hollow pins 11. The plurality of hollow pins 11 are arranged in the width direction. The hollow pin 11 is connected to the tip of the core body 12. In FIG. 3, the extending axis 11y of the hollow pin 11 is indicated by a broken line.

  As shown in FIGS. 1 and 3, the core body 12 has a concentrating portion 13 whose width in the vertical direction decreases as it goes downstream. In FIG. 1, the upstream end portion of the collecting portion 13 is indicated by a broken line. The collecting part 13 has a function of collecting the skin material 32 separated upstream. The collecting portion 13 is disposed on the downstream side of the core 10. As for the concentration part 13, the upper half becomes the upper concentration part 13A, and the lower half is comprised by the lower concentration part 13B. A flow path (core material flow path 21) through which the core material 31 flows is disposed between the upper concentrated portion 13A and the lower concentrated portion 13B. As shown in FIG. 3, the upper surface 13 a of the collecting portion 13 is an inclined surface that is inclined downward toward the downstream side. The lower surface 13b of the collecting portion 13 is an inclined surface that rises and inclines toward the downstream side. A plurality of projecting step portions 14 projecting upward in a step shape are arranged on the upper surface 13 a of the collecting portion 13. A plurality of protruding step portions 14 that protrude downward in a step shape may also be disposed on the lower surface 13 b of the collecting portion 13. A gap 14 a formed by a gap between the protruding step portions 14 is disposed between the plurality of protruding step portions 14. Thus, by providing the protruding step portion 14 and the gap 14a, the flow of the skin material 32 becomes smooth. At the upstream end of the concentrating portion 13, the ridge portion 15 is notched so as to be flush with the protruding portion 15 extending in the width direction and the inclined surface of the surface (upper surface 13 a) of the concentrating portion 13. A notch 16 is arranged. The notches 16 are provided at both ends of the upstream end of the collecting portion 13. In FIG. 3, the protrusions 15 and the notches 16 on the upper surface 13 a of the concentration part 13 are illustrated, but the protrusions 15 and the notches 16 may also be provided on the lower surface 13 b of the concentration part 13. By providing the protrusion 15 and the notch 16, the skin material 32 is easily supplied to the end in the width direction where molding defects are likely to occur due to insufficient material. Therefore, good molding is performed.

  A core material inlet 17 into which the core material 31 flows is disposed at the tip of the concentration part 13. The core material inlet 17 is formed by an opening. The core material inlet 17 is connected to the material injection portion 56A of the first extruder 51A via a flow path (core material flow path 21). The core material inlet 17 is provided around the hollow pin 11.

  As shown in FIG. 1, the extrusion mold 1 has a flow path 20 through which a molding material 30 flows. The flow path 20 includes a core material flow path 21 in which the core material 31 flows and a skin material flow path 22 in which the skin material 32 flows. The core material flow path 21 is disposed in the core 10. The skin material flow path 22 may be formed by a gap between the outer frame mold 2 and the core 10. The skin material flow path 22 has a skin material flow path 22 a disposed on the upper side of the core 10 and a skin material flow path 22 b disposed on the lower side of the core 10. The skin material flow path 22a is formed by a gap between the core 10 and the outer frame mold upper part 2A. The skin material flow path 22b is formed by a gap between the core 10 and the outer frame mold lower part 2B. The skin material flow path 22 may be provided on the side of the core 10. In that case, the skin material flow path 22 may be provided on the outer periphery of the core 10. Therefore, the skin material 32 can easily wrap the core material 31. The skin material 32 injected from the second extruder 51B into the outer frame mold 2 flows downstream along the inner surface of the outer frame mold 2.

  Skin material flow path 22 and core material flow path 21 merge in the vicinity of core material inlet 17. This junction point becomes the junction 23. In the merge part 23, the core material 31 and the skin material 32 merge. Downstream of the merging portion 23, the molding material 30 flows through the cylindrical flow path 20 surrounded by the outer frame mold 2. At this time, since the hollow pin 11 exists, the outer peripheral shape of the hollow pin 11 is reflected and the hollow portion 43 is formed. And the molding material 30 after shaping | molding is taken out from the exit 2p of the outer frame metal mold | die 2. FIG. The outlet 2p of the outer frame mold 2 can be said to be the outlet of the extrusion mold 1. The cross-sectional shape of the hollow pin 11 is an appropriate shape such as a polygon such as a quadrangle (for example, a square, a rectangle, a rhombus), a hexagon or an octagon, a shape having a curve such as a circle or an ellipse, or a star shape. Good. The cross-sectional shape of the hollow pin 11 is reflected in the shape of the hollow portion 43. In the molded body 40 of FIG. 4, a rectangular hollow portion 43 having a slightly rounded corner is illustrated.

  As shown in FIG. 1, the extrusion mold 1 has an enlarged flow path portion 3 in which the flow path 20 of the molding material 30 becomes larger toward the extending axis 11 y of the hollow pin 11 near the outlet of the outer frame mold 2. Have. Due to the presence of the enlarged flow path portion 3, the core material 31 is decompressed before the outlet 2 p of the outer frame mold 2. Therefore, the core material 31 easily expands toward the hollow pin 11 in the enlarged flow path portion 3. As described above, the core material 31 is expanded in the outer frame mold 2 before exiting from the outlet 2p of the outer frame mold 2 in advance, so that the core material 31 of the outer frame mold 2 can be removed. The expansion is suppressed, and the spread on the skin material 32 is suppressed. Thereby, molding defects are reduced. In the enlarged flow path part 3, the shape of the inner surface of the outer frame mold 2 may be maintained upstream of the enlarged flow path part 3. In addition, the extending | stretching axis | shaft 11y of the hollow pin 11 is a virtual straight line which passes along the center vicinity of the hollow pin 11, and advances in the direction where the hollow pin 11 extends | stretches. The extending shaft 11y of the hollow pin 11 extends in the flow direction. The extending shaft 11 y of the hollow pin 11 can extend near the center of the hollow portion 43 of the molded body 40.

  In the example of FIG. 1, the enlarged flow path portion 3 has a structure in which the cross-sectional area of the hollow pin 11 becomes small near the outlet of the outer frame mold 2. By reducing the cross-sectional area of the hollow pin 11, the flow path 20 expands near the outlet of the outer frame mold 2. FIG. 1 is an example of a hollow pin 11 having a structure for forming the enlarged flow path portion 3.

  The hollow pin 11 shown in FIG. 1 includes a base portion 11A, a tapered portion 11B, and a protruding portion 11C. The base portion 11 </ b> A is a portion that extends in the flow direction so that the hollow pin 11 forms the hollow portion 43 downstream of the joining portion 23. The base 11A may have substantially the same cross-sectional shape in the direction perpendicular to the extending direction of the hollow pin 11 over the extending direction. The base 11A may be connected to the core body 12.

  The tapered portion 11B is a portion that is disposed downstream (front end side) from the base portion 11A and tapers so that the cross-sectional area decreases toward the front end. In the taper portion 11B, the cross-sectional area of the hollow pin 11 gradually decreases. When the tapered portion 11B is provided in this way, the core material 31 can be gradually decompressed and gently expanded, so that the core material 31 is peeled from the skin material 32 as compared with the case where the core material 31 is expanded at once. Is suppressed.

  The protruding portion 11C is disposed downstream (tip side) of the tapered portion 11B. 11 C of protrusion parts are formed in the extending direction in substantially the same cross-sectional area. The protruding portion 11C protrudes downstream from the tip of the tapered portion 11B. The protruding portion 11C extends in the flow direction with a smaller cross-sectional area than the base portion 11A. When the protruding portion 11C is provided in this manner, the shape of the core material 31 expanded by decompression is adjusted, so that the molded body 40 in which the shape of the hollow portion 43 is stable can be easily obtained.

  The tip 11p of the hollow pin 11 is disposed at substantially the same position as the outlet 2p of the outer frame mold 2. Since the positions of the tip 11p of the hollow pin 11 and the outlet 2p of the outer frame mold 2 are aligned, molding defects are more easily suppressed.

  The molded body 40 is manufactured by extruding the molding material 30 using the extrusion mold 1. The molding material 30 includes a skin material 32 that forms the skin portion 42 and a core material 31 that forms the core portion 41. Here, the core material 31 may be an expandable material. The extrusion mold 1 is effective when the core material 31 has expandability. The expansibility of the core material 31 may be exhibited during molding. The core material 31 can be compressed during extrusion and released from compression when exiting the extrusion mold 1. The expandability of the core material 31 can occur when the extrusion pressure is released. The skin material 32 may have expansibility at the time of molding. However, the expanded flow path portion 3 is more effective when the expansibility of the core material 31 is larger than the expansibility of the skin material 32. This is because the extrusion mold 1 having the enlarged flow path portion 3 is effective when the core material 31 has a larger swell ratio than the skin material 32. The swell ratio is a ratio at which the cross-sectional area increases. The core material 31 and skin material 32 can be compressed during extrusion. When the compression rate of the core material 31 is larger than the compression rate of the skin material 32, the extrusion mold 1 is more effective. This is because the compressed material tends to return to the original state when it comes out of the mold, so that if the compression ratio of the core material 31 is high, the core material 31 easily spreads the skin material 32.

  In manufacturing the molded body 40, the skin material 32 is charged from the material inlet 55 </ b> B of the second extruder 51 </ b> B, and the skin material 32 is extruded and injected into the outer frame mold 2 of the extrusion mold 1. At the same time, the core material 31 is introduced from the material inlet 55A of the first extruder 51A, the core material 31 is extruded, and injected into the core 10 of the extrusion mold 1.

  As a molding material used for the core material 31 and the skin material 32, an appropriate cement-based molding material is used. Ceramic moldings can be obtained from cement molding materials. Specific examples of the cement-based molding material include, for example, a mixture in which cement, silica, reinforcing fibers, water, and the like are blended. As said cement, well-known cements, such as a Portland cement, a blast furnace cement, an alumina cement, a fly ash cement, can be used. Silica is a siliceous raw material, and appropriate silica is used. Examples of the reinforcing fibers include natural fibers such as pulp fibers, organic fibers such as vinylon and polypropylene, and inorganic fibers such as glass fibers, rock wool, and carbon fibers. The cement-based molding material may contain only one of the above listed reinforcing fibers, or may contain two or more. In addition, the cement-based molding material may contain aggregates, lightweight aggregates, water reducing agents, thickeners, and other additives. For example, mica and other lightweight aggregates may be included. The mixing ratio and mixing method of each component constituting the cement-based molding material are not particularly limited, and can be appropriately set according to the physical properties required for the ceramic-based molded body to be produced and the intended use. Note that the molding material for forming the ceramic molding is not limited to the cement molding material, and other hydraulic inorganic materials, ceramic materials, firing materials such as clay, and the like can be used.

  In the molded body 40, the cement-based molding material can be applied as the material used as the core material 31 and the skin material 32, but the core material 31 and the skin material 32 are defined as different materials. For example, the core material 31 and the skin material 32 may have different components. Moreover, the core material 31 and the skin material 32 may contain the same component, but content of each component may differ. For example, the composition (components and content) in the solids is the same, and the core material 31 can contain different materials by containing more water than the skin material 32. If the core material 31 contains more water than the skin material 32, the core material 31 becomes lighter and less solid material is obtained, so that the molded body 40 can be reduced in weight and cost.

  The core material 31 and the skin material 32 may have different air contents. In this case, the core material 31 and the skin material 32 may have the same solid content and different moisture ratios relative to the solid content, and may have the same composition except for the air content. Also good. Thereby, the core material 31 and the skin material 32 having different physical properties are easily formed from the molding material. For example, if the core material 31 contains more air than the skin material 32, the core material 31 becomes lighter and less solid material is obtained, so that the molded body 40 can be reduced in weight and cost. The air content can be controlled by the difference in the degree of vacuum of the decompression performed in the extruder 51. For example, the vacuum degree (degree of reduced pressure) of the core material 31 is set lower than the vacuum degree (degree of reduced pressure) of the skin material 32. That is, the pressure of the vacuum part 53A of the first extruder 51A is made higher than the pressure of the vacuum part 53B of the second extruder 51B. Then, the core material 31 has a higher air content than the skin material 32. Here, when the degree of vacuum of the core material 31 is low, even when a soft material (generally a material having a low viscosity or a material having a low specific gravity) is used as the core material 31, it can be easily evacuated (depressurized). Thus, degassing of the core material 31 is facilitated. For example, in the core material 31 containing a large amount of water, the viscosity is low, so that when the degree of vacuum is increased, the vacuum device may suck the core material 31, but the phenomenon is suppressed by reducing the degree of vacuum. Is done. Furthermore, since the core material 31 is arranged inside the molded body 40 and does not appear on the outer peripheral surface of the molded body 40, bubbles remain in the core portion 41 of the molded body 40 because the core material 31 contains a large amount of air. Even so, quality problems are unlikely to occur. Thus, there is an advantage in reducing the degree of vacuum of the core material 31.

  In manufacturing the molded body 40, the skin material 32 flows into the skin material channel 22. The core material 31 flows into the core material flow path 21. The skin material 32 flowing through the skin material flow path 22 is branched in the middle and flows through the upper skin material flow path 22a and the lower skin material flow path 22b. The skin material 32 may flow on the outer periphery of the core 10. The core material 31 flowing through the core material flow path 21 flows toward the downstream where the hollow pin 11 is disposed. Then, the skin material 32 and the core material 31 merge in the extrusion mold 1. The merging is performed at the merging unit 23. Specifically, in the gathering portion 13, the skin material 32 flowing through the upper skin material flow path 22a is directed downward, and the skin material 32 flowing through the lower skin material flow path 22b is directed upward. Then, the skin material 32 and the core material 31 merge at the point where the skin material channels 22a and 22b and the core material channel 21 merge. At this time, the skin material 32 is disposed around the core material 31. The core material 31 is disposed around the hollow pin 11.

  As shown in FIG. 1B, the molding material 30 that flows through the flow path 20 after merging flows further downstream. The molding material 30 flowing toward the downstream reaches the enlarged flow path portion 3 in the vicinity of the outlet 2p of the outer frame mold 2. Then, in the enlarged flow path portion 3, the core material 31 expands toward the extending axis 11 y side of the hollow pin 11. At this time, since the skin material 32 is surrounded by the outer frame mold 2 in the enlarged flow path portion 3, the core material 31 cannot expand in the direction of expanding the skin material 32, and goes toward the hollow pin 11. Inflates in the direction. Therefore, cracks and tearing of the skin portion 42 due to the spread of the skin material 32 are suppressed. Further, peeling between the skin part 42 and the core part 41 is suppressed. After the enlarged flow path portion 3, the molding material 30 is taken out from the extrusion mold 1. Thus, the molded body 40 is molded.

  The molded body 40 extruded from the extrusion mold 1 can normally become a ceramic-based plate material through a plurality of processes such as press molding, cutting, curing treatment, and cosmetic coating. In press molding, an uneven pattern can be imparted to the surface. In addition, a patterning roll may be arranged at the exit of the extrusion mold 1 to immediately give a concavo-convex pattern to the extruded molding material 30.

  FIG. 5 shows another example of the extrusion mold 1 and extrusion molding using the same. FIG. 5 is composed of FIGS. 5A to 5H. In the extrusion mold 1 shown in FIG. 5, the cross section of the hollow pin 11 is small in the vicinity of the outlet of the outer frame mold 2, as in the example of FIG. 1. The enlarged flow path portion 3 is formed by a structure in which the cross-sectional area of the hollow pin 11 is reduced. The same components as those described above are denoted by the same reference numerals. Open arrows indicate the direction of flow.

  In the extrusion mold 1 of FIG. 5A, the hollow pin 11 has a base portion 11A and a tapered portion 11B. The hollow pin 11 does not have the protruding portion 11C described above. An end face 11q of the tip of the tapered portion 11B is disposed at the tip 11p of the hollow pin 11. FIG. 5B shows a state of extrusion molding using the extrusion mold 1 of FIG. 5A.

  In the extrusion mold 1 of FIG. 5C, the hollow pin 11 has a base portion 11A and a tapered portion 11B. The hollow pin 11 does not have the protruding portion 11C described above. The tip 11p of the hollow pin 11 is configured by a tip of a tapered portion 11B that is tapered and sharpened. FIG. 5D shows a state of extrusion molding using the extrusion mold 1 of FIG. 5C.

  In the extrusion mold 1 of FIG. 5E, the hollow pin 11 has a base portion 11A and a protruding portion 11C. The hollow pin 11 does not have the tapered portion 11B that is tapered as described above. The protrusion 11C protrudes downstream from the tip of the base 11A with a size smaller than that of the base 11A. The cross-sectional area of the protruding part 11C is smaller than the cross-sectional area of the base part 11A. Therefore, the flow path 20 expands at the boundary portion between the base portion 11 </ b> A and the protruding portion 11 </ b> C, and the enlarged flow path portion 3 is provided in the vicinity of the outlet of the outer frame mold 2. FIG. 5F shows a state of extrusion molding using the extrusion mold 1 of FIG. 5E.

  In the extrusion mold 1 of FIG. 5G, the hollow pin 11 includes a base portion 11A, a tapered portion 11B, and a protruding portion 11C, as in FIG. 1, but the tip 11p of the hollow pin 11 is an outer frame mold. 2 is disposed downstream of the outlet 2p. It can be said that the tip 11 p of the hollow pin 11 protrudes from the outer frame mold 2. However, the tapered portion 11B is disposed upstream of the outlet 2p of the outer frame mold 2. Therefore, the cross-sectional area of the hollow pin 11 is small before the outlet 2p of the outer frame mold 2. Thereby, the flow path 20 spreads in the vicinity of the outlet of the outer frame mold 2 and the enlarged flow path portion 3 is provided. Thus, the position of the tip 11p of the hollow pin 11 may be shifted from the position of the outlet 2p of the outer frame mold 2. Furthermore, the tip 11p of the hollow pin 11 may protrude outward from the outlet 2p of the outer frame mold 2. In short, if the flow path 20 expands before the outlet 2p of the outer frame mold 2, the expanded flow path portion 3 is provided, and good molding is performed. FIG. 5H shows a state of extrusion molding using the extrusion mold 1 of FIG. 5G.

  5B, FIG. 5D, FIG. 5F, and FIG. 5H, also in the form shown in FIG. 5, since the enlarged flow path portion 3 is provided, the core material 31 expands before leaving the outer frame mold 2. Therefore, spreading to the skin material 32 is suppressed, and molding is performed satisfactorily.

  FIG. 6 shows an extrusion mold 1 and another example of extrusion molding using the same. FIG. 6 includes FIGS. 6A to 6F. In FIG. 6, the enlarged flow path portion 3 has a structure in which the tip 11 p of the hollow pin 11 is disposed upstream of the outlet 2 p of the outer frame mold 2. Thus, also when the front end 11p of the hollow pin 11 is located inside the outer frame mold 2, the flow path 20 through which the molding material 30 flows is expanded, so that the expanded flow path portion 3 is formed. The same components as those described above are denoted by the same reference numerals. Open arrows indicate the direction of flow.

  In the extrusion mold 1 of FIG. 6A, the hollow pin 11 protrudes downstream while maintaining the cross-sectional area of the base portion 11A. The hollow pin 11 does not include the tapered portion 11B and the protruding portion 11C having a smaller cross-sectional area than the base portion 11A described above. It can be said that the hollow pin 11 is retracted from the opening of the outer frame mold 2. FIG. 6B shows a state where extrusion is performed using the extrusion mold 1 of FIG. 6A.

  In the extrusion mold 1 of FIG. 6C, the hollow pin 11 includes a base portion 11A, a tapered portion 11B, and a protruding portion 11C. The shape of the hollow pin 11 may be the same as that shown in FIG. However, the hollow pin 11 shown in FIG. 6C is different from FIG. 1 in that the tip 11p is located upstream of the outlet 2p of the outer frame mold 2. FIG. 6D shows a state of extrusion using the extrusion mold 1 shown in FIG. 6C.

  In the extrusion mold 1 of FIG. 6E, the hollow pin 11 includes a base portion 11A and a tapered portion 11B, but does not include the protruding portion 11C described above. The hollow pin 11 of the extrusion mold 1 of FIG. 6E has the same shape as that of FIG. 5A, but differs in the position of the tip 11p. FIG. 6F shows a state of extrusion molding using the extrusion mold 1 of FIG. 6E.

  As shown in FIGS. 6B, 6D, and 6F, in these embodiments, since the enlarged flow path portion 3 is provided, the core material 31 expands before leaving the outer frame mold 2, so that the skin material is used. The expansion to 32 is suppressed and molding is performed satisfactorily. 6C and 6E, the enlarged flow path portion 3 has a structure in which the cross-sectional area of the hollow pin 11 is reduced in the vicinity of the outlet of the outer frame mold 2, and the hollow pin upstream of the outlet 2p of the outer frame mold 2 11 has a structure in which 11 tips 11p are arranged.

  As can be understood from FIGS. 5 and 6, the extrusion mold 1 has a portion in which the flow path 20 of the molding material 30 becomes larger toward the extending axis 11 y of the hollow pin 11 near the outlet of the outer frame mold 2. What is necessary is just to have (expanded flow path part 3). Various other modifications will be understood from FIGS. 5 and 6.

  Extrusion molding was performed using the extrusion mold 1 shown in FIG. As the molding material 30, the following were used.

  As a skin material, 43 parts of cement, 43 parts of siliceous raw material, 5 parts of pulp, and 1 part of additive were mixed, and 40 parts of water was added to a total of 100 parts of the solid content of this mixture. Using. Further, as a core material, 43 parts of cement, 43 parts of siliceous raw material, 5 parts of pulp, and 1 part of additive were mixed, and 60 parts of water was added to a total of 100 parts of the solid content of this mixture. A thing was used. The skin material and the core material have the same solid content, but different water contents.

  As a comparative example, an extrusion mold 1α shown in FIG. 7A was prepared. FIG. 7 is composed of FIGS. 7A to 7C. As shown in FIG. 7A, the extrusion mold 1α of the comparative example does not have the enlarged flow path portion 3. The hollow pin 11 projects downstream to the position of the outlet 2p of the outer frame mold 2 with the same cross-sectional area. Except for the shape of the hollow pin 11, the extrusion mold 1α of FIG. 7A may be the same as the extrusion mold 1 of the example of FIG.

  When extrusion molding was performed using the extrusion mold 1α of FIG. 7A, a molded body 40α shown in FIG. 7C was obtained. In the molded body 40α, tears 44 of the skin portion 42α were observed at the boundary between the skin portion 42α and the core portion 41α at the end in the width direction of the molded body 40α. FIG. 7B shows a schematic diagram of extrusion molding using the extrusion mold 1α of FIG. 7A. As shown in FIG. 7B, in the extrusion mold 1α of FIG. 7A, when the molding material 30 comes out of the extrusion mold 1α, the core material 31 expands outward and the skin material 32 is expanded (see FIG. 7B). (See the line arrow in the figure). Therefore, it is considered that the skin material 32 has been torn.

  On the other hand, in the extrusion molding using the extrusion mold 1 of FIG. 1, the skin portion 42 did not tear. This is considered because the core material 31 expanded inward before the outlet 2p of the outer frame mold 2 as shown in FIG. 1B. Therefore, it was confirmed by the enlarged flow path portion 3 that molding defects are suppressed. Moreover, when the extrusion mold 1 of FIG. 1 was used, there was no expansion after coming out of a mold, and the formation of the molded object 40 was also favorable.

  When the extrusion mold 1 shown in FIG. 1 is used, the base 11A of the hollow pin 11 is formed with a diameter larger than that of the hollow pin 11 of the extrusion mold 1α shown in FIG. May be.

DESCRIPTION OF SYMBOLS 1 Extrusion die 2 Outer frame die 3 Expanded flow path part 11 Hollow pin 11y Extending shaft 30 Molding material 31 Core material 32 Skin material 40 Molded body 41 Core part 42 Skin part 43 Hollow part

Claims (3)

An extrusion mold for forming a molded body having a hollow portion and having a core portion and a skin portion covering the core portion by extruding a molding material,
An outer frame mold for forming an outer frame of the molded body;
A hollow pin forming the hollow portion of the molded body,
In the vicinity of the outlet of the outer frame mold, an extrusion mold having an enlarged flow path portion in which the flow path of the molding material becomes larger toward the extending axis of the hollow pin.   The enlarged flow path section has a structure in which the cross-sectional area of the hollow pin is reduced in the vicinity of the outlet of the outer frame mold, and a structure in which the tip of the hollow pin is disposed upstream of the outlet of the outer frame mold The extrusion mold according to claim 1, comprising at least one of the following. A method for producing a molded body, wherein the molding material is produced by extruding the molding material using the extrusion mold according to claim 1 or 2,
The molding material includes a skin material that forms the skin portion, and a core material that forms the core portion,
Combining the skin material and the core material in the extrusion mold,
In the enlarged flow path part, the core material is expanded on the extending axis side of the hollow pin,
A method for producing a molded body, wherein the molding material is removed from the extrusion mold.

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