WO2023189063A1

WO2023189063A1 - Method for producing molded article

Info

Publication number: WO2023189063A1
Application number: PCT/JP2023/006655
Authority: WO
Inventors: 璃奈近藤; 真子宇佐見
Original assignee: 愛三工業株式会社
Priority date: 2022-03-29
Filing date: 2023-02-24
Publication date: 2023-10-05
Also published as: JP2023146089A

Abstract

A method for producing pellets (52) containing powder includes first preparing a kneaded material (50) by kneading the powder and a liquid. The kneaded material (50) is extruded to produce a rod-shaped filament (51) that is thinner than the kneaded material (50). At least a surface of the filament (51) is solidified. The solidified filament (51) is cut to a prescribed length from the tip thereof.

Description

Method for manufacturing molded bodies

The technology disclosed in this specification relates to a method for manufacturing a molded object.

For example, an evaporated fuel processing device for a vehicle such as an automobile is provided with an adsorber for adsorbing and desorbing evaporated fuel. The adsorber is filled with a porous adsorbent that adsorbs evaporated fuel generated within the fuel tank. The evaporated fuel adsorbed by the adsorbent is desorbed into the purge passage when the vehicle is running, that is, when the internal combustion engine is operating, and is supplied to the intake passage leading to the internal combustion engine.

Porous adsorbents include powders of organic and inorganic substances such as MOF (Metal Organic Frameworks), inorganic substances such as zeolite, and organic substances such as activated carbon. The porous adsorbent is formed into pellets having a predetermined shape, such as a columnar shape, by kneading powder together with a binder and a solvent and extruding the kneaded product. In order to obtain sufficient adsorption performance of the adsorber, it is necessary to fill the adsorber with pellets in a suitable arrangement. Therefore, it is preferable that the pellets be formed with high accuracy, such as the straightness of the cylindrical shaft and the circularity of the cross section.

Japanese Patent Publication No. 7-64646 discloses a molding process in which ceramic powder and liquid binder are kneaded, the kneaded product is molded using an extrusion molding machine, and then the molded body is heated (degreased) to remove the binder. A method of manufacturing the body is described. Therefore, the molded body is cut into pellets in a soft state containing a binder before being heated. Therefore, the pellets may be deformed during cutting, resulting in variations in shape after cutting.

JP-A-8-266238 discloses a method of kneading powder such as grains and water (solvent), heating the kneaded product to remove water, and then extruding the dried kneaded product. The manufacturing method is described. Therefore, since water is removed from the kneaded product before extrusion molding, the viscosity increases and deformation during cutting is suppressed. However, since the specific surface area of the kneaded product before extrusion molding is small, it is difficult to efficiently remove water from the kneaded product. Moreover, due to an increase in the viscosity of the kneaded material, the energy required for extrusion molding may increase, or extrusion molding may become difficult due to high pressure molding.

The problem to be solved by the technology disclosed in this specification is to suppress variations in shape after processing while reducing manufacturing costs when manufacturing a molded body containing powder.

In order to solve the above problems, the technology disclosed in this specification takes the following measures.

One embodiment of the present disclosure is a method for manufacturing a molded body containing powder. Create a mixture by kneading powder and liquid. The kneaded material is extruded to create rod-shaped filaments that are thinner than the kneaded material. Solidify at least the surface of the filament. The solidified filament is cut at a predetermined length from its tip.

Therefore, the kneaded product containing liquid and having a low viscosity is extruded. This allows extrusion molding to be easily performed at low pressure (low energy). In addition, wear and the like of extrusion molding jigs can be suppressed. Therefore, the manufacturing cost of the molded body can be reduced. Moreover, by extruding the kneaded product into thin rod-shaped filaments, the specific surface area of the filaments can be increased. Therefore, the surface of the filament can be solidified in a short time. Thereby, deformation of the filament can be suppressed when cutting the tip of the filament, and variations in the shape of the molded product after cutting can be suppressed.

FIG. 1 is a schematic diagram of a molded body manufacturing apparatus according to a first embodiment. FIG. 2 is a perspective view of a pellet obtained by cutting the tip of a filament. FIG. 3 is a cross-sectional view of the filament in a plane parallel to the cut plane. It is a flowchart which shows the manufacturing flow of the molded object based on 1st Embodiment. FIG. 2 is a schematic diagram of a molded body manufacturing apparatus according to a second embodiment. It is a flow chart which shows the manufacturing flow of the molded object concerning a 2nd embodiment.

A preferred first embodiment of the present disclosure will be described based on FIGS. 1 to 4. The same reference numbers in the description refer to the same elements with the same function, without redundant description. FIG. 1 is a schematic diagram showing a molded body manufacturing apparatus, FIG. 2 is a perspective view of a pellet, which is a molded body, FIG. 3 is a sectional view of a filament in a plane parallel to the cutting surface, and FIG. 4 is a flowchart showing the manufacturing flow of the molded body. It is. In each figure, the vertical direction is defined as the direction in which gravity acts downward.

As shown in FIG. 1, the molded body manufacturing apparatus 10 forms pellets 52 from the input kneaded material 50 as a molded body. The kneaded material 50 includes powder as a main component, a binder that binds the powder, and a solvent that kneads the powder and binder. The powder is, for example, MOF, zeolite, porous material such as activated carbon, wood powder, carbon, or a mixture of multiple types thereof. That is, the powder includes any of organic and inorganic substances, inorganic substances, and organic substances. The binder is, for example, a resin material such as cellulose or polyvinyl alcohol, or a mixture of a plurality of these materials. Powdered binders are generally used, but liquid binders may also be used. The solvent is a liquid, such as water, alcohol, or a mixture of multiple types thereof. The weight ratio of the powder in the kneaded material is greater than that of the binder. The pellets 52 are used as a porous adsorbent for adsorbing evaporated fuel generated in a fuel tank, for example, in a vehicle's evaporative fuel processing system.

As shown in FIG. 1, the molded body manufacturing apparatus 10 includes a kneading section 12, an extrusion section 20, a solidification section 30, and a pellet forming section 40 in order from the top. The kneading section 12 kneads the powder, binder, and solvent to generate a kneaded material 50. The extrusion molding section 20 extrudes the kneaded material 50 to form rod-shaped filaments 51. The solidifying section 30 solidifies at least the surface of the filament 51. The pellet forming section 40 cuts the tip of the filament 51 to form a cylindrical pellet 52.

As shown in FIG. 1, the kneading section 12 has a cylindrical screw case 13 and a screw 14 rotatably supported inside the screw case 13. At the top of the screw case 13, an input port 13a is provided for inputting the powder, the binder, and the solvent. From the input port 13a, the binder and solvent are first introduced and kneaded, and then the powder is further introduced and kneaded. The screw 14 rotates around a rotation axis extending in the vertical direction. As the screw 14 rotates, the powder, binder, and solvent are kneaded to produce a kneaded material 50. The screw 14 feeds the kneaded material 50 toward the extrusion molding section 20 below while kneading it.

As shown in FIG. 1, the extrusion molding section 20 has an extrusion blade 21 and a die 22. The extrusion blade 21 is attached to the lower end of the screw 14 and is rotatable together with the screw 14. The die 22 is provided below the extrusion blade 21. The die 22 has a plurality of cylindrical die holes 22a passing through it in the vertical direction. The die 22 is supported by a die holder 23 attached to the lower end of the screw case 13. As the extrusion blade 21 rotates, the kneaded material 50 is extruded downward from the die hole 22a of the die 22. Thereby, the kneaded material 50 is extruded into rod-shaped filaments 51 that are thinner than before extrusion.

As shown in FIG. 1, the solidification section 30 has a cylindrical drying chamber 31 that extends in the vertical direction. The lower end of the drying chamber 31 is sealed by a filament holder 41, which will be described later. The drying chamber 31 is generally sealed from the outside air. The solidification section 30 has a heater 32 in the upper part of the drying chamber 31 . The heater 32 is arranged below the die 22 so as to surround from the outside a plurality of filaments 51 that are extruded downward from the plurality of die holes 22a. The heater 32 heats the filament 51 to volatilize the kneaded liquid (solvent). The heating temperature of the heater 32 is set at a temperature below which the properties of the powder do not change. Here, the alteration of powder includes, for example, chemical alteration such as decomposition, carbonization, and oxidation of powder components, and physical alteration such as splitting and melting of the structure of powder.

As shown in FIG. 1, a liquid recovery port 34 is provided on the side surface of the drying chamber 31. The liquid recovery port 34 is provided near the lower end of the heater 32. The liquid recovery port 34 is connected to the vacuum device 33 via a pipe. The air containing the liquid volatilized within the drying chamber 31 is sucked by the vacuum device 33 . The vacuum device 33 cools the intake air and collects the condensed liquid.

As shown in FIG. 1, the pellet forming section 40 has a filament holder 41 that supports the lower part of the filament 51, and a cutter 42 that cuts the lower end of the filament 51. The filament holder 41 is provided with a filament support hole 41 a having approximately the same diameter as the filament 51 . The lower end of the filament 51 is fed downward from the filament support hole 41a. A propeller 42a having, for example, three blades is supported outside the lower end of the drying chamber 31. The propeller 42a rotates around a rotation axis extending in the vertical direction. A cutting tool 42 is provided on the front surface of each blade of the propeller 42a in the rotational direction. As the propeller 42a rotates, the cutting tool 42 cuts the lower end of the filament 51 in the horizontal direction.

As shown in FIG. 2, the filament 51 is formed into a rod shape with a circular cross section and a diameter 51b centered on a central axis 51a extending in the vertical direction. Since the filament 51 is extruded downward along the direction of gravity, the central axis 51a has high straightness. Furthermore, since the filament 51 has a high straightness of the central axis 51a, the filament 51 has a high degree of circularity around the central axis 51a. The pellet 52 having a circular cross section is formed by cutting a predetermined length 52b from the lower end of the filament 51. The pellet 52 has a cylindrical shape with cut surfaces 52a at the upper and lower ends. The length 52b can be changed based on the feed amount for extruding the filament 51 and the rotational speed of the propeller 42a (see FIG. 1).

As shown in FIG. 3, when the filament 51 is heated by the heater 32 (see FIG. 1), a predetermined amount of liquid evaporates from the surface 51c. As a result, a region having a thickness 51e from the surface 51c to the boundary surface 51d is formed as a dry and solidified layer. As an indicator that the surface 51c of the filament 51 is dry, it is preferable that the amount of volatilization of the liquid immediately before cutting the filament 51 is 5% by weight or more based on the content of the liquid immediately after extrusion molding. More preferably it is % by weight.

As shown in FIG. 1, the pellet 52 formed by the cutting tool 42 falls and is stored in the collection case 43. The pellets 52 are sent from the collection case 43 to the sieving machine 44. The particle sizer 44 shapes the end faces of the pellets 52 to further increase the straightness and roundness of the shafts of the pellets 52.

The flow of molding the pellet 52, which is a molded object, will be explained based on FIGS. 1 and 4. First, powder, binder, and liquid (solvent) are put into the screw case 13 (step (hereinafter referred to as ST) 1). The screw 14 kneads the input powder, binder, and liquid to generate a kneaded material 50 (ST2). The extrusion blade 21 extrudes the kneaded material 50 downward toward the die 22. As a result, a rod-shaped filament 51 with a circular cross section is formed (ST3). The heater 32 heats the filament 51 from its surroundings in the drying chamber 31 to volatilize, for example, 5% by weight of the liquid from the surface of the filament 51 (ST4).

The cutting tool 42 cuts the tip of the filament 51 coming out downward from the drying chamber 31 to a predetermined length. As a result, a cylindrical pellet 52 is formed (ST5). The vacuum device 33 recovers the liquid volatilized within the drying chamber 31 through the liquid recovery port 34 (ST6). The pelletizing machine 44 shapes the end surfaces of the pellets 52 formed by cutting (ST7). In this way, pellets 52 with small variations in shape can be shaped, and the collected liquid can be reused.

As described above, in the method for manufacturing pellets (molded bodies) 52 containing powder, first, as shown in FIG. 1, powder and liquid are kneaded to create a kneaded product 50. The kneaded material 50 is extruded to create rod-shaped filaments 51 that are thinner than the kneaded material 50. At least the surface of the filament 51 is solidified. The solidified filament 51 is cut at a predetermined length from its tip.

Therefore, the kneaded material 50 containing liquid and having a low viscosity is extruded. This allows extrusion molding to be easily performed at low pressure. Furthermore, wear of the extrusion blades 21 and the die 22 can be suppressed. Therefore, the manufacturing cost of the pellets 52 can be reduced. Moreover, by extruding the kneaded material 50 into thin rod-shaped filaments 51, the specific surface area of the filaments 51 can be increased. Therefore, the surface of the filament 51 can be solidified in a short time. Thereby, deformation of the filament 51 can be suppressed when cutting the tip of the filament 51, and variations in the shape of the pellets 52 after cutting can be suppressed.

As shown in FIG. 3, at least the surface 51c of the filament 51 is solidified by volatilizing the liquid from at least the surface 51c of the filament 51. Therefore, the liquid can be volatilized from the surface 51c of the filament 51 having a large specific surface area in a short time and with less energy. Furthermore, the surface 51c of the filament 51 can be solidified all around in the circumferential direction.

As shown in FIG. 1, the liquid volatilized from the filament 51 is collected. Therefore, the collected liquid can be used repeatedly. Further, by removing the volatilized liquid from around the filament 51, volatilization of the liquid can be promoted.

As shown in FIG. 1, the kneaded material 50 is extruded downward to form filaments 51. Therefore, the influence of gravity on the filament 51 can be minimized. Therefore, bending of the molded filament 51 can be suppressed, and the filament 51 can be extended straight in the vertical direction. Thereby, variations in the shape of the pellets 52 after cutting can be further suppressed. Moreover, it is possible to suppress the filaments 51 from being recombined with each other after molding.

Next, a second embodiment of the present disclosure will be described based on FIGS. 5 and 6. The molded body manufacturing apparatus 60 of the second embodiment includes a solidification section 62 in place of the solidification section 30 of the molded body manufacturing apparatus 1 shown in FIG. The solidification section 62 has a cylindrical drying chamber 63 that extends in the vertical direction. The lower end of the drying chamber 63 is sealed by the filament holder 41. The drying chamber 63 is generally sealed from the outside air. The solidification section 62 has a cooler 64 in the upper part of the drying chamber 63 . The cooler 64 is arranged below the die 22 so as to surround from the outside the plurality of filaments 51 that are extruded downward from the plurality of die holes 22a. The cooler 64 cools the filament 51 and solidifies the liquid (solvent) kneaded into the filament 51. The cooling temperature of the cooler 64 may be set below the freezing point of the liquid and above a temperature at which the chemical and physical properties of the powder do not change.

As shown in FIG. 5, an opening 66 is provided on the side surface of the drying chamber 63. The opening 66 is provided near the lower end of the cooler 64. Opening 66 is connected to vacuum pump 65 via a pipe. By starting the decompression pump 65, the pressure inside the drying chamber 63 is reduced. The solvent kneaded into the filament 51 is volatilized or sublimed from the surface of the filament 51 by reduced pressure. As an indicator that the surface 51c of the filament 51 is dry, the amount of solvent volatilization is preferably 5% by weight or more, and more preferably 5% by weight, based on the content of the liquid immediately after extrusion molding. .

As shown in FIG. 5, a liquid recovery port 68 is provided on the side surface of the drying chamber 63. Liquid recovery port 68 is provided below opening 66 . Liquid recovery port 68 is connected to vacuum device 67 via a pipe. The air containing the solvent volatilized within the drying chamber 63 is sucked by the vacuum device 67 . A vacuum device 67 cools the intake air and collects the condensed liquid.

The flow for molding pellets 52, which are molded objects, will be explained based on FIGS. 5 and 6. First, powder, binder, and liquid (solvent) are put into the screw case 13 (ST11). The screw 14 kneads the input powder, binder, and liquid to generate a kneaded material 50 (ST12). The extrusion blade 21 extrudes the kneaded material 50 downward toward the die 22. As a result, a rod-shaped filament 51 with a circular cross section is formed (ST13). The cooler 64 cools the drying chamber 63 to solidify the liquid kneaded on at least the surface of the filament 51 (ST14). The vacuum pump 65 reduces the pressure in the drying chamber 63 to volatilize, for example, 5% by weight of the liquid from the surface of the filament 51 (ST15).

The cutting tool 42 cuts the tip of the filament 51 coming out downward from the drying chamber 63 to a predetermined length. As a result, a cylindrical pellet 52 is formed (ST16). The vacuum device 67 recovers the liquid volatilized within the drying chamber 63 through the liquid recovery port 68 (ST17). The granulator 44 shapes the end faces of the pellets 52 formed by cutting (ST18). In this way, pellets 52 with small variations in shape can be shaped, and the collected liquid can be reused.

As described above, in the method for manufacturing the pellet (molded body) 52 containing powder, at least the surface of the filament 51 is solidified by cooling the filament 51, as shown in FIG. Therefore, even when using powder that may be altered by heating, for example, the surface of the filament 51 can be solidified in a short time.

As shown in FIG. 5, after at least the surface of the filament 51 is solidified by cooling, the liquid is evaporated from the filament 51. Therefore, the surface of the filament 51 is temporarily solidified by cooling, and the solidified state is maintained for a long time by further volatilizing the liquid. Therefore, deformation of the filament 51 during cutting can be further suppressed.

Although specific embodiments have been described above, the technology disclosed in this application can also be implemented with various other modifications. In the embodiment, a method of kneading powder, a binder, and a liquid (solvent) to generate the kneaded material 50 was exemplified. Alternatively, the kneaded material 50 may be generated by kneading only powder and liquid without including the binder, for example. Although the method of forming the cylindrical pellets 52 has been exemplified, the shape of the pellets 52 is not limited to this, and may be, for example, a prismatic shape, a cylindrical shape with a hollow axis, or the like.

The method of producing the kneaded material 50 using the screw 14 rotating within the screw case 13 has been illustrated. Alternatively, the kneaded material 50 may be produced using a mortar and pestle, for example. The extrusion molding section 20 that extrudes the kneaded material 50 toward the die 22 using the extrusion blades 21 is illustrated. Instead of this, for example, a method may be used in which the kneaded material is pushed out toward the die 22 using a piston.

A configuration in which a heater 32 or a cooler 64 is provided to solidify the surface of the filament 51 has been illustrated. Alternatively, for example, the filament 51 may not be heated or cooled, and the liquid kneaded into the filament 51 may be volatilized only by reducing the pressure inside the drying chamber. Instead of the heater 32, for example, a configuration may be used in which heated gas is circulated within the drying chamber 31. Instead of the cooler 64, for example, a configuration may be used in which cooled gas is circulated within the drying chamber 31. Although it is preferable that the

liquid recovery ports

34 and 68 be arranged immediately below the heater 32 and the cooler 64, the arrangement location is not limited to this and may be changed as appropriate. The molded body manufacturing apparatus 60 is illustrated in which a decompression pump 65 and a vacuum device 67 are provided. Alternatively, for example, by starting the vacuum pump 65, the pressure inside the drying chamber 63 may be reduced and the air containing the volatilized liquid may be recovered at the same time.

According to another aspect of the present disclosure, at least the surface of the filament is solidified by volatilizing the liquid from at least the surface of the filament. Therefore, the liquid can be volatilized from the surface of the filament having a large specific surface area in a short time and with less energy. Moreover, the surface of the filament can be solidified over the entire circumferential direction.

According to another aspect of the present disclosure, at least the surface of the filament is solidified by cooling the filament. Therefore, even when using powder that may be altered by heating, for example, the surface of the filament can be solidified in a short time.

According to another aspect of the present disclosure, after at least the surface of the filament is solidified by cooling, the liquid is evaporated from the filament. Therefore, the surface of the filament is temporarily solidified by cooling, and the solidified state is maintained for a long time by further volatilizing the liquid. Therefore, deformation of the filament during cutting can be further suppressed.

According to another aspect of the present disclosure, the liquid volatilized from the filament is recovered. Therefore, the collected liquid can be used repeatedly. Further, the volatilization of the liquid can be promoted by removing the volatilized liquid from around the filament.

According to another aspect of the present disclosure, the kneaded material is extruded downward to form filaments. Therefore, the influence of gravity on the filament can be minimized. Therefore, bending of the molded filament can be suppressed, and the filament can be made to extend straight in the vertical direction. This further suppresses variations in the shape of the molded body after cutting. Further, it is possible to suppress the filaments from being recombined with each other after molding.

The various embodiments described above in detail with reference to the accompanying drawings are representative examples of the present invention and are not intended to limit the present invention. The detailed description is provided to teach those skilled in the art to make, use and/or implement various aspects of the present teachings and does not limit the scope of the invention. Furthermore, each of the additional features and teachings described above may be applied and/or used separately or in conjunction with other features and teachings to provide improved methods of making and/or using molded bodies. Thing.

Claims

A method for producing a molded body containing powder, the method comprising:
kneading the powder and liquid to create a kneaded product;
Extruding the kneaded product to create a rod-shaped filament thinner than the kneaded product,
solidifying at least the surface of the filament;
A method for producing a molded body, which comprises cutting the solidified filament at a predetermined length from its tip.
A method for producing a molded article according to claim 1, comprising:
A method for producing a molded body, comprising solidifying at least the surface of the filament by volatilizing the liquid from at least the surface of the filament.
A method for producing a molded article according to claim 1, comprising:
A method for producing a molded body, comprising solidifying at least the surface of the filament by cooling the filament.
A method for manufacturing a molded article according to claim 3, comprising:
A method for producing a molded body, comprising solidifying at least the surface of the filament and then volatilizing the liquid from the filament.
A method for producing a molded article according to claim 2 or 4, comprising:
A method for producing a molded body, comprising recovering the liquid volatilized from the filament.
A method for producing a molded article according to any one of claims 1 to 5, comprising:
A method for producing a molded body, comprising extruding the kneaded material downward to mold the filament.