JPH0358883B2 - - Google Patents

Description

Detailed Description of the Invention [Industrial Field of Application] The present invention relates to a method for producing a porous molded article whose main raw material is a viscoelastic material. The present invention relates to a method for manufacturing a molded article economically and in any size.

[Conventional technology]

In recent years, porous molded bodies in the form of plates or blocks made by adding a binder to a viscoelastic material such as a porous inorganic substance or a porous synthetic resin have been widely used as filter materials, adsorbents, sound absorbing materials, heat insulating materials, catalyst carriers, etc. ing.
The present inventors have been conducting research on a method for economically producing a high-quality porous molded product having a microporous structure, and have previously filed a patent application (Japanese Unexamined Patent Application Publication No. 1983-1993). −116134).

That is, the method for producing a porous molded product according to the above application is, for example, as shown in FIG. A molding mold 3 is installed below, and a molding pedestal 4 is installed in the mold 3.
This is a method carried out using a device arranged to be able to move up and down, in which the viscoelastic material A filled in the cylinder 1 is pressed by a ram 6, extruding it linearly from the nozzle hole 5 and descending in the vertical direction. At the same time, the linear extrudate is spirally wound and laminated onto the pedestal 4 and further onto the extrudate lamination surface. By drying and firing this, it has been possible to economically produce a porous molded body of better quality than a honeycomb molded body.

However, in the above manufacturing method, since the stacking direction of the linear extrudates is limited to the vertical direction, it is only possible to obtain a molded product with a cross-sectional area that is approximately the same as the extrusion die frontage, and it is difficult to obtain a molded product with a large cross-sectional area. In this case, the opening area of the extrusion die and the extrusion cylinder had to be increased in size. In addition, when trying to manufacture molded products of various sizes, it is necessary to prepare extrusion dies, etc. corresponding to the sizes, and there is also the problem that the complicated work of extrusion dies must be replaced frequently. .

[Problems to be Solved by the Invention] In the prior art, the size of the molded product that can be manufactured is determined by the size of the molding device. Therefore, the biggest problem is that in order to produce a molded article of a desired size, a correspondingly sized molding device, particularly an extrusion die, must be used. Therefore, as mentioned above, it is necessary to prepare extrusion dies of various sizes, and work efficiency deteriorates due to extrusion quizzes being replaced, and a large amount of material is lost during replacement, which increases the manufacturing cost of the molded product. is rising. The present invention was completed as a result of repeated studies to overcome the above-mentioned problems, and it is possible to economically produce a molded article having a cross-sectional area of any size without replacing the molding device, especially the extrusion die. The purpose is to provide a method.

[Means for solving problems]

The present invention has achieved the above object by extruding a viscoelastic material through a number of nozzle holes provided in an extrusion die, lowering it vertically at a constant speed, landing it on a receiving surface in a spiral shape, and extruding it. The gist is that the spiral objects are stacked in the height direction by keeping the distance between the lower surface of the die and the landing surface substantially constant and moving the receiving surface laterally at a constant speed in one way or back and forth. It has the following.

[Effect]

The operation of the above means will be explained in more detail. However, as a basic principle, the extrusion die will be explained with nozzle holes arranged in a single row. First, a viscoelastic material such as a porous inorganic substance or a porous resin is put into a cylinder or the like equipped with an extrusion die. The viscoelastic material is then pressurized by a ram sliding inside the cylinder, extruded at a constant speed through a number of single row nozzle holes provided in an extrusion die, and suspended vertically.
The hanging material from each nozzle is wound spirally and landed on a receiving surface provided at a constant interval from the bottom surface of the nozzle. At this time, if the receiving surface is moved in the lateral direction perpendicular to the single row of nozzle holes, the landing point of the spiral extrudate will move, so while lying flat on the receiving surface, spread a carpet on the receiving surface. It will unfold like this. At this time, the receiving surface is moved so that the distance between the nozzle hole and the landing point is maintained approximately constant.
It is necessary to do it. The distance between the nozzle hole and the landing point is approximately 10 to 100 mm and is appropriately selected. The present invention can be developed in various ways after that, but a typical example is when the distance from the start point of implantation of the helical extrudate is a desired length (length to give a desired cross-sectional area).
When reaching the point, reverse the direction of movement of the receiving surface,
In addition, the receiving surface is lowered by the height of the helical extrudate, a new helical extrudate is deposited and stacked on top of the already deposited helical extrudate, and when it returns to the deposit start point, it is moved downward and reversed again. . Thereafter, the stacking is continued while repeating the above reciprocating movement until the stacking thickness reaches a predetermined thickness, thereby making it possible to obtain a molded article having a desired cross-sectional area and thickness. By drying the molded product thus obtained and then subjecting it to a calcination treatment, a small molded product having excellent performance as a catalyst carrier or the like is obtained. In the above explanation, the moving direction of the transfer belt is uniaxial, but the movement in the direction orthogonal to the above moving direction is combined to make biaxial movement, so that the direction of development of the vertically adjacent spiral objects is Mutually orthogonal laminates may also be formed. The molded body thus obtained has high mechanical strength because the developing directions are perpendicular to each other.

Furthermore, by further developing the above principle, multiple rows of nozzle holes of the extrusion die are also arranged in the direction of movement of the receiving surface (that is, they are arranged so as to spread from front to back, left and right), and the deviation of the landing position in the direction of movement is utilized. By stacking the spiral extrudate layer that descends and lands from the rear row nozzle hole in the traveling direction on the spiral extrudate layer that descends and lands from the front row nozzle hole in the traveling direction, a predetermined thickness is obtained. You can also finish it. Therefore, in order to obtain a molded body of a predetermined length, extrusion of the viscoelastic material may be stopped when the moving length reaches the above-mentioned predetermined length, but extrusion may be continued without stopping and continued in the moving direction. Alternatively, a long molded product may be made and finally cut. By drying and firing the obtained molded body in the same manner as described above, a porous molded body that can be used as a catalyst carrier or the like can be obtained.

In an example in which there are a plurality of nozzle holes, adjustment can be made by adjusting the number of rows. Further, the lamination thickness is determined by the number of rows and the number of reciprocating movements.

In addition, in the present invention, it is necessary to prevent the wires from intersecting with each other in the middle of hanging down and disrupting the spiral state, and to prevent the wires from being too far apart from each other, resulting in insufficient bonding between the implants. In order to avoid this, it is desirable to adjust the radius of the spiral drawn by the linear object on the top surface of the transfer belt. (diameter of the nozzle hole), so the above-mentioned interval and cross-sectional diameter are adjusted respectively to obtain the best results. After setting, the reciprocating movement of the receiving surface is mechanically controlled so that the interval is always substantially constant. Furthermore, for the same reason, it is desirable to suitably adjust the spacing between the nozzle holes.

Raw materials for the viscoelastic material used as described above in the present invention include inorganic substances (porous inorganic substances and non-porous inorganic substances) and synthetic resins, but more specifically, they are as follows. .

First, porous inorganic substances include zeolite (whether synthetic or natural), γ-alumina,
Examples include silica gel, silica/alumina, boehmite, activated titania, activated carbon, and molecular sieving carbon. Mullite (3Al ₂ O ₃ ) and corundum (α-
Al ₂ O ₃ ), cordierite (2Al ₂ O ₃・2MgO・
Examples include metal oxide-containing minerals such as 5SiO ₂ ).
These inorganic substances are generally available as powder or granules, and when extruding them into a linear shape,
A binder as described below is added and kneaded to prepare a viscous viscoelastic material.

In addition, the synthetic resin is preferably one that carbonizes in a non-oxidizing atmosphere to form fine pores, and such resins include cyclic groups (saturated carbocyclic groups, saturated heterocyclic groups, aromatic groups, non-oxidizing groups). Examples include synthetic resins containing saturated heterocyclic groups, etc., among which thermosetting resins such as phenolic resins, aniline resins, xylene/formaldehyde resins, and melamine resins are most suitable. When these synthetic resins are used, they are crushed into powder, kneaded with a suitable binder, and extruded into a linear shape.

There are no particular restrictions on the binder, and any binder can be used as long as it exhibits a caking function for powder and granules. Typical examples include MC, CMC, starch, CMS (carboxymethyl starch), HEC (hydroxyethyl cellulose), HPC (hydroxypropyl cellulose), sodium lignin sulfonate, calcium lignin sulfonate, polyvinyl alcohol, and acrylic ester. , methacrylic acid ester, phenolic resin, melamine resin, etc.; water glass, colloidal silica, colloidal alumina,
Examples include inorganic binders such as colloidal titanium, bentonite, and aluminum phosphate, and of course, two or more of these may be used in combination. The blending ratio of the binder is 35% by dry weight (based on the total kneaded material)
It is preferable to set it to the following value; if it exceeds this value, the strength of the final product will decrease, so it is not recommended.

There are no restrictions on the mixing and kneading means, and known devices and equipment may be used.
When a screw type extrusion molding machine is used for extrusion, the screw of the molding machine can also be used for kneading. The material kneaded in this way is
Extrusion is carried out using the above-mentioned screw type extrusion molding machine or plunger type extrusion molding machine. In a series of steps from extrusion to lamination molding, the spiral extrudates are bonded together with a large number of fine gaps formed therebetween, thereby making it possible to obtain a porous molded product with low ventilation resistance.

〔Example〕

FIG. 1 is a perspective view showing the first embodiment, and FIG. 2 is a cross-sectional view taken along the line - in FIG.
The die block 8 is attached to the lower end flange portion 1a of the cylinder 1, and the discharge die 2 is attached to the lower surface of the die block 8, and the discharge die 2
The nozzle holes 5 are bored in a row in a direction parallel to the long side of the die block 8. During molding, the viscoelastic material A filled in the cylinder 1 and die block 8 is extruded linearly at a constant speed from the nozzle hole 5 of the discharge die 2 by pushing down the ram 6, and is caused to fall vertically. It is placed on a transfer belt 4a disposed substantially horizontally below the molding device S. At this time, since the linear object B has viscoelasticity, the transfer belt 4a
After hitting the upper surface of the plane, they complete the landing by drawing a spiral. On the other hand, the transfer belt 4a is moving in the direction of arrow D by a roll 9 whose shaft 9 rotates in the direction of arrow C, and as mentioned above, the linear object B that has landed on the upper surface of the transfer belt 4a is shown in FIG. As shown, it lies flat in a coil shape and is unfolded onto the belt 4a. In this way, the linear object B is inserted by a predetermined length from the implantation start line M.
As the landing progresses, the direction of rotation of the roll 9 is indicated by the arrow while continuing to extrude the linear material B from the nozzle 5.
The moving belt 4a is lowered by the thickness of the linear object B which has been reversed in the C' direction and has landed on the floor. In this way, the direction of movement of the transfer belt 4a is changed to the direction of arrow D'. As a result, the newly hanging linear object B' lands on top of the linear object B (the first layer in the figure) that has already landed, as shown in Figure 3 (side view). to form a second layer. In this way, when the landing of the second layer returns to the landing start point, the landing direction is reversed and lowered, and the third and subsequent layers are stacked up to a predetermined stacking height. In this way, a molded article having a desired width and thickness can be obtained.

FIG. 4 is a side explanatory view showing the second embodiment, in which nozzle holes 5a, 5b, 5c are bored in three rows in a direction perpendicular to the long side of the die 2 (extending in the penetrating direction of the paper), and The transfer belt 4 is the landing surface for the object B.
b is arranged to be inclined, and the transfer belt 4b is rotated in the direction of arrow E. Nozzle holes 5a, 5b, 5c
When the linear object B is lowered at a constant speed, the landing position is different in the direction of movement of the transfer belt 4b, so in the figure, the linear object that has descended from the nozzle hole 5a becomes the lowest layer, and the nozzle 5b and nozzle 5c are placed above it. The linear objects descended from each nozzle are stacked one after another to form a three-layer linear object stack.The transfer belt 4b is tilted to transfer the linear objects descending from each nozzle from the bottom surface of the die 2 to the landing point. Since the distance and the descending speed of the linear object are constant, the spiral linear object formed by descending from one nozzle has a similar spiral radius, and in this case, the spiral linear object descends from one nozzle and has a similar spiral radius. A stack of linear objects having slightly different diameters is obtained.

FIG. 5 is a cross-sectional view showing a third embodiment, in which three rows of nozzle holes 5d, 5e, and 5f are bored stepwise in a direction perpendicular to the long side of the die 2.
The step length d from d to 5f is designed to be approximately equal to the height d' of one spiral linear object B. Then, the linear material B is extruded and lowered from the nozzle holes 5d to 5f onto the transfer belt 4a running substantially horizontally in the direction of the arrow, thereby obtaining a three-layered linear material laminate as shown. In the above embodiment, since the vertical distances between the lower surfaces of the nozzle holes 5d to 5f and the landing positions of the linear objects are designed to be equal, the turning radii are approximately equal, and a homogeneous linear object stack is produced. can be obtained.

Example of Use As an example of use of the porous molded body according to the present invention, there is a radiator as shown in FIG. That is, the radiator F is held at the upper part of the U-shaped container K with both ends supported, and the combustion exhaust gas introduced from the inlet S provided on the side wall is radiated out of the system through the pores of the radiator. It also functions to reflect radiant heat. In such a radiator F, if the radiator breaks due to thermal shock and falls into the container, it may lead to a serious accident. However, since the porous body according to the present invention cracks in a certain direction, if it is arranged as shown by I in FIG. 7, the radiator F will not fall even if it breaks, and it is extremely effective for such applications.

〔Effect of the invention〕

The present invention is constructed as described above, and in particular, since the receiving surface is moved horizontally one way or back and forth, it is possible to create any size by simply adjusting the moving length of the receiving surface without replacing the cylinder or discharge die. It is possible to obtain a molded body with a long diameter and a uniform helical diameter.

[Brief explanation of drawings]

Fig. 1 is a perspective view showing one embodiment of the method of the present invention, Fig. 2 is a sectional view taken along the line - - in Fig. 1, Fig. 3 is a side view showing the stacked state of linear objects, and Fig.
FIG. 6 is an explanatory view showing another embodiment, FIG. 6 is an explanatory cross-sectional view showing a conventional manufacturing method, and FIG. 7 is a perspective view showing an example of use of the porous molded body according to the present invention. 1... Cylinder, 2... Discharge die, 3...
Molding mold, 4... pedestal, 5... nozzle hole, 6...
...Rum.

Claims (1)

[Claims] 1. A viscoelastic material is extruded through a number of nozzle holes provided in an extrusion die, is lowered vertically at a constant speed, and is deposited on the receiving surface in a spiral manner, and the distance between the lower surface of the extrusion die and the landing surface is A method for manufacturing a porous molded body, which comprises stacking spiral objects in the height direction by moving the receiving surface in one direction or back and forth in the lateral direction at a constant speed while holding the receiving surface substantially constant.