JPS58116134A - Porous molded body and manufacture thereof - Google Patents

Abstract

PURPOSE:To obtain the titled molded body with simple operation which is more uniform and whose resistance to air permeation is low, by extruding linearly a viscoelastic material such as an inorganic material from a plurality of nozzle openings of an extrusion die to wind spirally the extrudates in layers by a specific method. CONSTITUTION:A viscoelastic material (A) comprising an inorganic material (e.g. a zeolite, etc.) or a synthetic resin (preferably phenolic resins or the like) to which a binder is usually added is extruded linearly from the nozzle openings in the extrusion die 2 to descend vertically, and at the same time for example an item receiving table 4 is lowered gradually such that the distance (L) between the top of layers of the linear extrudates (B) and the outlet end of the extrusion die 2 is kept constant and the linear extrudates (B) are spirally wound in layers thereby providing the intended molded body wherein the adjacent spiral surfaces of the linear extrudates (B) are abutted on or eutangled in each other. EFFECT:The pressure drop is less and the performance is high.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a porous molded article whose main raw material is an inorganic substance or a synthetic resin, and a method for producing the same.

In recent years, the use of porous inorganic substances and porous synthetic resins has been rapidly developed, and they are used in a wide range of fields, such as filter materials, adsorbents, sound absorbing materials, heat insulating materials, and catalyst carriers. As application to such a wide range of fields is being considered, the raw shape of the material poses problems in terms of ease of handling in compost and influence on its effects, so it has to be used in the form of pellets, beads, rings, etc. It is now often used by forming it into a honeycomb shape or the like. The most suitable molded bodies are selected depending on the application, and honeycomb-shaped molded bodies are preferred in applications where pressure loss is averse, such as catalyst carriers used in reactions involving gaseous bodies. However, honeycomb structures are subject to major restrictions from the viewpoint of manufacturing technology, and because there are limits to the processing technology itself such as dies and forming rows 2, it is not possible to form a fine structure beyond a certain level. For example, in a molding method using dies, the cell wall thickness is limited to approximately 1oo#En, and even in throat molding methods, it is difficult to achieve a thickness of less than approximately 50μ, and in the end, the number of cells is 10mm per square inch.
00i1! [is considered to be the limit.

For this reason, press-molded products made by adding a binder to molded products are attracting attention. Such a press-formed body has extremely fine voids, and has the advantage that, when used as a catalyst carrier, for example, the effective surface area of the color is considerably larger than that of a honeycomb structure. However, when using an inorganic material as a material, it is necessary to use a binder for 21L during the pellet molding stage and the secondary molding stage, which not only affects the porosity of the product but also reduces its mechanical strength. There are also concerns that it may have a negative impact. In addition, in the conventional method, the formed pellet is crushed and sieved before press molding, which requires twice as much molding operation alone, resulting in an increase in processing cost.

The present inventors focused on the above-mentioned circumstances, and by completing the molding operation in one step, the present inventors created a porous structure with various fine pore structures that surpassed the honeycomb structure and were comparable to the above-mentioned press-formed structure. I continued my research to develop a quality molded jar. As a result, it was confirmed that the porous molded product obtained by extruding an inorganic material into a linear shape, accumulating it into a predetermined shape, drying and firing it has the properties that meet the above purpose. did. In addition, a linear extrusion molded mass was obtained by making 4rIJ11 from an organic synthetic resin, and the fin was carbonized by JI! After learning that it was possible to obtain a substantially porous molded body by processing, they filed a patent application with Hikari.

The present invention further improves the molded product and the molding method of the prior invention, and provides a porous molded product that is more homogeneous and has a ventilation resistance of 0.4%, and a method for producing the same. is an inorganic material *'x is a synthetic resin when a large number of linear extrudates are wound and layered in a spiral shape, and the spirally wound laminates mutually interact with each other on adjacent surfaces due to dust. There is a cost when they are joined or intertwined. The most suitable method for manufacturing this porous molded body is to linearly extrude a viscoelastic material made of an inorganic substance or synthetic resin through a number of nozzle holes provided in an extrusion die, and to drop the material in a vertical direction. The main idea is to stack the linear extrudates while spirally winding them upward while keeping the distance between the upward layer of extruded linear extrudates and the exit end of the extrusion die approximately constant. Any shape can be used as the extrusion die, and an aggregate can be obtained according to the shape of the selected extrusion die.

In addition, by adjusting the interval and diameter of the nozzle holes provided in the extrusion die, the size of the ventilation space in the accumulation pit can be adjusted as desired.
By performing SS, a porous molded body having a color and void density depending on the purpose can be manufactured with high productivity using a simple device.

Furthermore, in the case of using a non-porous inorganic substance as a material in the present invention, the above-mentioned aggregate may be made into a product as it is, and if an inorganic substance that becomes porous through a chemical treatment is used as a material, f! By drying and firing the aggregate to make each linear extrudate porous, it is possible to produce a porous molded body having extremely fine voids. Furthermore, when a synthetic resin is used as a material, the agglomerated mass is heat treated in a non-oxidizing atmosphere to carbonize it, or further subjected to an activation treatment to obtain a porous molded body with excellent performance as an adsorbent, etc. I can do it with Jin.

As mentioned above, the molding materials used in the present invention include inorganic substances (porous inorganic substances, non-porous inorganic substances) and synthetic resins, but more specifically, they are as follows. be.

First, porous inorganic substances include zeolite (whether synthetic or natural), r-allele, silica gel, silica arunna, boehmite, activated titania, activated carbon,
For example, Molex JL Chibip Carbon is exemplified. Mullite (3A1□j・ff
Examples include metal oxide-containing minerals such as ijHOm), kokundum (kure-^1*Os), and cordierite (2A!I03.2Mgo.5810a). These inorganic substances are generally available in the form of powder or granules, and when extruding them into linear shapes, a binder as described below is added and kneaded to make them viscous.

In addition, the synthetic resin is preferably one that carbonizes in a non-oxidizing atmosphere to form pores, and examples of such resins include sulfur groups (saturated carbocyclic groups, saturated polycyclic groups, aromatic groups, etc.).
Among them, thermosetting resins such as phenolic resins, aniline resins, xylene/formaldehyde resins, and melain resins are most suitable. When these synthetic resins are used, they are pulverized into powder, mixed with an inder, and extruded into a linear shape.

There is no limit on the percentage of binders, and it depends on whether you use any binder that exhibits a caking function for powder or granules. Typical examples include MC, CMC, starch, 0M8 (carboxymethyl starch), 1 (EC (hydroxyethyl cellulose), RPC (hydroxypropyl cellulose), sodium lignin sulfonate, calcium lignin sulfonate, polyvinic acid). alcohol,
Organic binders such as acrylic acid ester, methacrylic acid beauty salon hair, phenolic resin, and membrane resin; Inorganic binders such as water glass, colloidal silica, colloidal aluminum, colloidal titanium, bentonite, and plutonium phosphate are exemplified. Of course, two or more of these may be used together. The blending ratio of the binder is 3 in terms of dry violet content.
It is preferable that the amount is 5% or less (based on the whole refined product); if it exceeds this value, the strength of the finished product will decrease, so it is not recommended.

There are no restrictions on these mixing and kneading means, and Koyo's equipment and equipment may be used. However, when using a screw extrusion molding machine for extruding a linear material, the screw of the molding machine must be You can also use it to mix lines. The rope material thus produced is extruded into a linear material using the above-mentioned screw set extrusion molding machine or plunger set extrusion molding machine. This series of steps from extrusion of the linear material to lamination molding is the most characteristic part of the present invention, and is the key to obtaining a porous molded product with low ventilation resistance.

That is, FIG. 1 is a schematic vertical cross-sectional view illustrating the horizontal 1-step process of extruding a linear object in the present invention, and in the figure, 1t is an extrusion cylinder, 2 is a discharge die, 3 is a molding die, and 4 is a Each molded product holder is shown. In the present invention, a discharge die 2 with a large number of nozzles 5 is installed vertically at the tip of the extrusion cylinder 1 placed therein, and a molding die 3 is placed below it. A molded product holder 4 is disposed within the mold 3 so as to be movable.

Then, the mixer A is loaded into the cylinder l, and the ram 6
By pressing, the mixed wire material ^ is discharged all at once from each nozzle 5, and a linear material B is formed. After coming out of the nozzle 5, the --shaped materials B fall vertically and hit the upper surface of the molded body holder 4, as shown, and are stacked one on top of the other, each drawing a substantially circular spiral.

In this case, the radius of the spiral that the --shaped object B draws on one upper surface of the molded object holder 4 is determined by the distance L1 between the lower surface of the die 2 and the upper surface of the stack, the cross-sectional diameter of the linear object B (the diameter of the nozzle 5), and the nozzle 5. 5, and the relationships shown in FIGS. 2 to 4, respectively. That is, as the distance becomes more current, as the cross-sectional diameter of the thin wire material B becomes larger, and as the distance t between the nozzles 5 becomes more energized, the winding diameter of the screw thread becomes smaller. Here, the cross-sectional diameter of the linear object B and the interval t between the nozzles 50 and 50 are uniquely determined by the discharge die 5 used. All you have to do is set . The above-mentioned spacing between and ζ is the length of the molded body holder 4. As the amount of laminated windings of h increases, the length becomes shorter, so if the pedestal 4 is fixed, the spiral diameter will gradually change, and at the bottom of the stack, the spiral diameter will change due to the incoming current, so the spirals will intersect with each other. The spiral loops of gold become distorted.On the other hand, in the upper part of the mound layer, the spiral diameter becomes smaller, so adjacent windings are separated and formed separately, and the porosity of the molded body as a whole becomes unstable. Alternatively, when the independent winding columns reach a certain height, they tilt in irregular directions, resulting in non-uniformity of the entire molded body.

Therefore, in the present invention, the molded object holder 4 is gradually lowered four times in a continuous manner according to the extrusion molding speed of the linear portion B, and molding is performed while maintaining the above-mentioned interval at a constant latency.

As a result, the four helical sources of the linear material remain constant in the vertical direction, making it impossible to obtain a molded body with a constant filling rate (beating porosity) throughout. Moreover, the voids formed in the centers of the four pillars of each spiral penetrate downward <-h, as shown in Figure 5 (*enlarged plan view of the finished cedar body), so that adsorbents and catalysts can It depends on whether pressure loss can be kept to a low level when used as a carrier, etc. By adjusting the above-mentioned spacing so that the turning diameter of the spiral direction is approximately equal to the drilling pitch (4) of the nozzle 5, it is possible to obtain a molded body in which each Al11lI7II! If the above-mentioned spacing is set to Al1fJ so that the swirl diameter is smaller than the drilling pitch of the nozzle 5, a molded body in which the spirals are entwined with each other can be obtained, for example, as shown in No. sIA.In this case, the entanglement of the spirals The void in the center of each 1 g spiral column becomes small, and the pressure loss of the rutted road formed body is greatly reduced.Therefore, the above spacing is set to 814#L [tmF of spiral entanglement.
By changing lt, it is possible to obtain a molded article having electrical ventilation resistance depending on the purpose of use. However, if the spacing is too large, a regular helical diameter cannot be obtained, so the spacing should be 10 times or less the helical diameter (ie, nozzle pitch).

The wound laminate obtained in the above manner may be dried and fired or carbonized to a temperature of t to produce a product, but if this is done, the metal strength of each screw-wound column will be insufficient. There are some spears that lack strength and empty rates that are too competitive, so
After winding and stacking, it is desirable to pressurize from the top and bottom as shown in Figure #I7, and spread it out in the lateral direction to improve mutual adhesion.

Fig. 1 shows an example in which the molding wheel 3 is fixed to form a spiral winding pillar in the vertical direction. If #4 is rotated at an uneven speed, #A will form the rotational body in a spiral shape, and this spiral OSm will reduce the ventilation resistance of the final molded body.
I! It is also difficult to do so.

In addition, in the example shown in Figure 5, the discharge die is configured to have 20 nozzles, 15 nozzles, and a constant nozzle pitch to maintain a constant overall packing density. It is also possible to curse the quality of the body to 1. Specific examples of such configurations include the configurations shown in FIG. 8 (lower Rki diagram of part of the discharge die 2) and FIG. 9 (corresponding to the cross-sectional view taken along the line ■-■ in FIG. 8). That is, in this example, the nozzle 51 located at the outermost circumference of the discharge die 2 is formed into a semicircular shape, and the nozzle 5b at the center is formed into a circular shape.

Since the number of passages of the mixed material A extruded from the nozzle 5 is almost the same, the speed of the mixed material A passing through the semicircular nozzle 5m is higher than the speed of the mixed material A passing through the central circular nozzle 5b. Moreover, the semicircular extrudate is laminated in a spiral manner with the semicircular flat part inside, as shown in Figure 1O (an explanatory diagram showing the rolled and laminated state of the linear material extruded from the outermost nozzle 51). be done. This is better than turning the flat part horizontally. This is because there is less turning resistance when turning in the same direction. As a result of the forging, the helical winding density on the outer circumferential side is denser in the vertical direction than in the center, and the strength of the outer skin is strengthened, resulting in an increase in the strength of the entire molded body. For the same purpose, it is also effective to increase the packing density on the outer side by reducing the nozzle pitch on the outer circumferential side.

The present invention is roughly constructed as shown in E, and since it is difficult to obtain a high-performance porous molded body with low pressure loss, the range of application as an adsorbent or catalyst carrier can be greatly expanded. It's slow to go. Attached reference photographs 1 to 3 show porous molded bodies according to the present invention.

[Brief explanation of the drawing]

FIG. 1 is an explanatory diagram hinting at the manufacturing method of the porous molded body according to the present invention, and FIGS. 2 to 4 are the distance L1 between the lower end of the discharge nozzle and the once laminated portion of the linear material, the 0 cut of the linear material [11 and Discharge nozzle spacing (pitch) L is linear-〇IIIA whirling i! Figure 1115.6 is a partially enlarged graph showing the influence of il diameter on the porous molded body according to the present invention. , 9 illustrates a preferred die according to the present invention, and FIG.
9 is a partial bottom view, FIG. 9 is a cross-sectional view taken along the line ■--■ in FIG. 8, and FIG. 10 is an explanatory diagram showing a spirally wound state of a semicircular linear object. 1... Extrusion cylinder, 2... Dice, 3...
Molding mold, 4... Molded object holder, 5... Nozzle, 6
...Rum.

Claims (1)

[Scope of Claims] 11) A large number of linear extrudates made of an inorganic substance or synthetic IN resin are each spirally wound and laminated, and the Ill spirally wound laminates are connected to each other on adjacent surfaces. A porous molded body that is joined or intertwined. (211?vM In claim 1, a porous molded article in which the linear extrudate has a different cross-sectional shape and/or a different cross-sectional area. (3) In claim 1 or 2, a spiral A porous laminate in which the outer shell side of the spirally wound laminate has a higher lamination density than the central part. (5) A viscoelastic material made of an inorganic substance or synthetic resin is linearly extruded through a number of nozzle holes provided in an extrusion die in a vertical direction. While lowering the extruded linear extrudates, the distance between the stacked top surface of the extruded linear extrudates and the exit end of the extrusion die is kept approximately constant, and the linear extrudates are stacked while being spirally wound toward the stacking top surface. (6) In claim 6, the distance between the top surface of the stack of linear extrudates and the exit end of the extrusion die is 10 times or less the distance between the die holes. A method for producing a porous molded body.