WO2007009931A1 - Method and device for separating pasty moulding materials - Google Patents

Abstract

The invention relates to a method for separating pasty moulding materials by means of an extrusion device consisting in extruding said moulding materials through a plurality of openings. Said invention is characterised in that the extruded pasty moulding materials are separated by one or several fluid films, wherein the fluid film exhibits a continuous volume flow rate associated with a parallel distribution along a distance equal to or greater than 5 cm calculated from the fluid film point of origin. A device for separating the pasty moulding materials is also disclosed.

Description

Process and device for dicing pasty molding compounds

description

The present invention relates to a process for dicing pasty molding compositions using an extrusion apparatus, wherein the molding compositions are extruded through a plurality of openings on a die plate, which is characterized in that the extruded, pasty molding compositions are separated by one or more fluid films the fluid film has a continuous volume flow with a parallel distribution over a distance of at least 5 cm, calculated from the place of origin of the fluid film. Furthermore, the invention relates to a device for dicing pasty molding compounds.

In technical processes often fall to process steps in which pasty masses must be cut. Such processes are used for example in the mass production of plastic products, pharmaceutical products, cleaning and personal care products, foods, animal feed or catalysts in which pasty masses are deformed.

Examples which may be mentioned include extrusion processes in which pasty masses are processed in an extrusion apparatus and brought into a form that is necessary in terms of process technology or application. In this case, a die is usually attached to the exit of the extrusion apparatus, the geometry of which determines the diameter and the cross-sectional shape of the molding leaving the extrusion apparatus. In this way, for example, strands or

Hollow strands of various diameters, cross-sectional shapes and geometries were obtained.

In order to separate the pasty masses and thus to adjust the length of the molded articles, the extrusion devices are equipped with teeing devices which specifically cut to length an endless molding emerging from the extrusion device. In general, this cutting is accomplished by means of impact or cutting tools, these tools are usually made of metal, ceramic, plastic or corresponding composite materials.

JP 06 063937 describes a dicing device using an energy beam. This jet is located in the center of the circular extrusion orifices and breaks up the extrudates, in which the jet moves continuously in a circle over the extrudate openings.

EP-A 830 927 describes a process for cutting extrudates using water jets. The water jets are generated by means of nozzles. Several nozzles are arranged so that the water jets of each nozzle covered segment of the extrusion openings, in which the nozzles move alternately on a circular motion path.

US 3,846,529 discloses a method for cutting extrudates using a gas curtain. The gas curtain is created by a nozzle and a subsequent deflector. The distance from the deflector to the extrusion openings, i. the length of the extrudates, is flexibly adjustable.

US 5,063,002 describes a process for producing small particles of an elastomeric material. The extrudates are crushed by means of an air system which has a sufficiently high speed, dried and discharged from the crushing chamber. The gas source is at right angles to the extrusion orifices and is connected to the cutting chamber via a necked throat means so that the cross-sectional area of the throat means increases to those extrusion orifices closest to the exit region.

WO 2004/69507 describes a process for dicing a paste-like molding composition, in which the molding composition is brought into contact with a stream containing a fluid medium. It is disclosed that the flow is brought into contact with the molding compounds via outlet openings. As outlet openings nozzles are disclosed, in particular flat nozzles, wherein the resulting fluid film has a parabolic or trapezoidal distribution.

Despite the improvements that have been made in recent years, there is still a need for optimization, particularly with respect to optimized space utilization, i. an increase in production with the same working hours and the same space requirements. There is also a need for optimization with regard to a simplified design that is easy to adjust and clean.

A simple construction is especially important in those processes where the dies have to be changed every few hours. Furthermore, the nozzles of the prior art are expensive to clean. After cleaning, an adjustment of the individual nozzles is sometimes necessary.

The object of the present invention was therefore to show a structurally simple method for cutting to length paste-like molding compositions that can be easily adjusted and cleaned and also guarantees a high throughput of extrudates. Another object was to replace the nozzles used in the prior art.

A method has been described for dicing pasty molding compositions using an extrusion device, wherein the molding compounds are separated by a plurality of openings. be extruded on a die plate found, which is characterized in that the extruded, pasty molding materials are separated by one or more fluid films, wherein the fluid film has a continuous volume flow with a parallel distribution over a distance of at least 5 cm, calculated from the Location of the fluid film having.

The term "continuous", as used in the context of the present invention in connection with the volume flow and the parallel distribution, comprises a deviation of 0 to 10 percent relative to a distance of 5 cm.

The term "dicing", as used in the context of the present invention, comprises on the one hand process guides in which a part of the pasty molding composition is completely separated off. As an example of this complete separation is for example called the cutting to length of a molding compound. Likewise, the term "dicing" includes process guides in which said film is contacted with the molding compound such that the molding compound is not completely severed.

The term "molding composition" as used in the context of the present invention includes compositions which are subjected to at least one molding step. In this case, process guides are included, in which the shaping step consists in that the molding composition is broken according to the invention. Before the dicing according to the invention or following the dicing according to the invention or both before and after the dicing according to the invention, the pasty molding composition can be subjected to at least one further shaping step. Further shaping steps are described for example in DE-A 103 04 611 in the text passages [0013] to [0015].

In the context of the present invention, the term "fluid film" is understood as meaning all states of matter which lie below the conditions prevailing during dicing between ideal gas and solid and constitute a coherent film. Accordingly, the term "fluid" includes, for example, dense gases, liquids, melts or supercritical phases. Likewise, in the context of the present invention, finely divided solids in one or more gases or liquids, such as, for example, fluidized beds or magnetic liquids, constitute fluids. In the process according to the invention, gases or liquids are preferably used as fluids for producing the fluid film.

For example, nitrogen can be used as the fluid. This offers the advantage that nitrogen is already present on site in gas networks in many production processes. Likewise, a fluid film is conceivable, which consists of compressed air, which is also usually present on site in gas networks. Of course, but also other gases are up to Noble gases conceivable, wherein the stream may contain one or more gases or may consist of at least one gas.

Preferably, air is used as the fluid. By the term "air" as used in the present invention is meant a gas or gas mixture consisting essentially of nitrogen, preferably with nitrogen contents of greater than or equal to 78% by volume, and substantially in each laboratory and every production facility operated on a technical or industrial scale is permanently installed. Depending on the source from which the air originates, their composition may vary within the limits known to those skilled in the art.

If, for example, shaped catalyst bodies are produced in the process according to the invention, it is also conceivable to use a stream which comprises at least one reactive gas. For example, the surfaces that are formed by the dicing process can be oxidized by reactive gases such as oxygen or hydrogen can be reduced. Through such dicing processes, dicing and chemical reaction of the surfaces resulting from dicing are combined in the process according to the invention, which ensures a high process economy.

Two or more different fluids may also be used in the present invention. In this regard, for example, the stream used to break up the pasty molding material may contain two or more different fluids, for example two or more different gases or two or more different liquids being conceivable.

Advantageously, the fluid film has a volume flow per mm ² of 0.0001 to

50 Nm ³ / mm ² , preferably 0.001 to 20 Nm ³ / mm ² , particularly preferably 0.01 to

5 Nm ³ / mm ² , in particular 0.1 to 2 Nm ³ / mm ² . This volume flow is advantageously constant over a distance of at least 10 cm, in particular of at least 20 cm.

The fluid film with parallel distribution advantageously has a horizontal spread of 1 to 60 mm, preferably 1 to 40 mm, in particular 15 to 25 on. The vertical spread of the fluid film is advantageously 0.1 to 20 mm, preferably 0.1 to 15 mm, in particular 0.3 to 5 mm.

Advantageously, the fluid film at a temperature of - 200 to 650 ⁰ C, preferably from -20 to 100 ⁰ C, in particular from 0 to 40 ⁰ C.

Advantageously, the fluid film is generated under a pressure of 1 to 100 bar, preferably from 1 to 20 bar, in particular from 2 to 6 bar. If, for example, a liquid is preferably used as the fluid, pressures and temperatures are generally used which are selected analogously to those used in water-jet cutting.

The fluid film can be produced continuously or discontinuously, for example plus-wise, advantageously the fluid film is produced continuously.

The fluid film is advantageously produced by dividing a fluid stream by a plurality of slit-like openings arranged in a circle. The fluid flow flows advantageously parallel, but in the opposite direction to the extruded molding compositions, in an inflow tube with a diameter of preferably 5 to 100 mm, preferably 20 to 30 mm. The tube is advantageously located in the center of the die plate of the extrusion device. At the end of the inflow tube, 0 to 100 mm, preferably 2 to 20 mm, in front of the die plate, the tube has slot-like outlet openings.

The aforementioned slot-like outlet openings are advantageously located on a circle. The outlet openings advantageously have a length, measured on the circumference of 1 to 60 mm, preferably from 1 to 40 mm, in particular 15 to 25, on. The distance between the individual slot-like openings is advantageously 0 to 60 mm, preferably 0 to 40 mm, in particular 0 to 15 mm. The outlet openings are advantageously 0.1 to 20 mm, preferably 0.1 to 15 mm, in particular 0.3 to 5 mm high. The circle diameter on which the slot-like outlet openings are located is advantageously 10 to 1000 mm, preferably 20 to 300 mm, in particular 50 to 200 mm. On the circle described are 1 to 25 slot-like outlet openings. Optionally, the fluid film is created over a single slot-like opening that makes up the entire circumference. Accordingly, a fluid film is formed, which is aligned perpendicular to the molding mass strands.

The inflow pipe is advantageously made of materials such as metals such as brass, acid-proof steel, heat-resistant steel, titanium, plastics such as polyvinyl chloride (PVC), polypropylene (PP) or Hastelloy, or two or more of these materials, especially stainless steel V2A.

The distance between the slot-like outlet openings to the die plate can be easily adjusted over metal rings of different thickness. The fluid film is advantageously 0 to 100 mm above the die plate, preferably 1 to 40 mm, in particular 3 to 15 mm.

Advantageously, several strands of a pasty molding material are cut periodically. For example, the strands of the molding compound can be moved past the outlet openings at a constant feed rate and with the outflow Fluid film are brought into contact. By the frequency with which the fluid film is applied, the length of the pieces can be controlled, which are separated from the respective strands. It is conceivable, inter alia, to also keep this pulse frequency constant at a constant feed rate of the strands, as a result of which strand pieces of the same length are obtained, for example. It is also possible to change the pulse frequency over time with a constant feed rate, whereby strand pieces of defined different lengths are obtained. It is also possible to change the feed rate continuously or discontinuously over time and to keep the pulse frequency constant or to change it continuously or discontinuously over time.

Advantageously, the die plate 1 to 50 openings for dies for extruding the pasty molding compositions. Each individual die advantageously has 1 to 50 extruded openings, preferably 1 to 25 extrudate openings. The extrudate openings suitably have a diameter of 0.5 to 50 mm, preferably 1 to 30 mm. The openings are advantageously arranged on 1 to 2 circles around the fluid inflow pipe. The distance between the centers of two adjacent openings for matrices on a circle is advantageously 20 to 80 mm. For example, with a circle radius of 140 mm, 16 openings for matrices are arranged. Thus, advantageously 16 to 800 strands are cut to length in parallel.

In the method according to the invention it is thus possible to cut off a very large number of individual extrudates with a dicing process. The slit-like fluid film openings and all the extrudate openings are advantageously in line in this case. 1 to 50, preferably 1 to 25 extrudates can be separated per fluid film. Thus, per dicing operation using a conventional dicing device with, for example, a circular radius of the openings of the dies of 140 mm, 5 to 800 mm ² , preferably 100 to 500 mm ² extrudate mass can be divided.

The pasty molding compositions advantageously have a viscosity of 300 to 5000 N / cm ² . Furthermore, the molding compositions have a density of 100 to 1500 g / l, preferably 300 to 1400 g / l. The diameter of the strands of pasty molding compositions is advantageously from 0.5 to 50 mm, preferably from 1 to 30 mm, in particular from 1.5 to 25 mm.

Such pasty molding compositions are obtained, for example, in the production or mass production of plastic products, pharmaceutical products, cleaning and personal care products, food products, animal feeds or catalysts.

The process according to the invention is particularly preferably used for the production of shaped catalyst bodies. For the purposes of the present invention, the term "shaped catalyst bodies" is to be understood as meaning shaped bodies which serve as a finished catalyst or as a catalyst precursor. Furthermore, catalyst form bodies may have at least one further, non-catalytically active constituent which, in the case of a catalyst precursor, may be removed from the shaped body, for example in at least one further treatment step, for example in a thermal treatment or a chemical reaction.

Examples of such catalysts include oxidation, hydrogenation, deoxidation, epoxidation, amination, alkylation, purification or reforming catalysts. Likewise catalysts for the removal of nitrogen oxides NO _x or for the decomposition of N 2 O may be mentioned.

Optionally, the fluid, in particular using a liquid, is collected after the dicing step and recycled to the process. If necessary, the fluid may be subjected to one or more suitable purification steps or treatment steps prior to recycling.

The present invention, in contrast to the prior art, a structurally simple method for cutting to length pasty molding compositions. The matrices, which have to be changed every few hours due to the abrasive material, are easy to remove and reinsert without the need for expensive (dis) assembly of the fluid film assembly. Furthermore, there is no need to re-adjust the fluid film arrangement after the die change, as is the case, for example, when changing nozzles. In addition, significantly more mold strands per unit time can be cut to length, since a) the spatial distribution of the die openings could be optimized and b) the fluid film has a separation force over a distance of several die openings due to the parallel distribution. Furthermore, the mold strands are already dried by the fluid film, so that, for example, the mold strands do not stick to other strands when falling onto a conveyor belt.

Furthermore, the invention relates to an apparatus for severing paste pasty masses with an extrusion device with a die plate having a plurality of extrudate openings, emerge from the extruded molding compounds through the openings, and with a fluid source which is arranged in the center of the die plate, wherein the Fluid exits through slit-like outlet openings, which are arranged in a circle.

The device according to the invention is explained in more detail below with reference to the drawings: It shows

Fig. 1 is a schematic representation of a plan view of the device according to the invention

Fig. 2 is a schematic representation of a side view of the device according to the invention

The device according to the invention has an extruder 6 with an extruder screw 7. Via the extruder 6, the pasty molding compounds reach the die plate 3, which has a plurality of openings for dies. Each die has a plurality of extrudate openings 4. The openings for dies are arranged in the form of several circles on the die plate 3. The fluid passes through the inflow pipe 5 to the center of the die plate. There, it emerges through slit-like outlet openings 1, which are arranged in a circle on the inflow pipe 5, and forms a fluid film 2.

Examples

Comparative example according to WO 2004/69507: Using the special jet nozzles mentioned in WO 2004/69507 (Schlick Co., designation 19828), a device for dicing pasty molding compositions was constructed, which was optimized for a circle radius of the openings for dies of 140 mm. In order to realize a uniform cutting, 8 openings for dies with a diameter of 23.8 mm on the circle radius of 140 mm could be used. Each die had 12 extrudate openings. Per extrusion process 96 extrudates could be produced.

Inventive Example 1: For comparison, a device for dicing pasty molding compositions was constructed using the method according to the invention, which was also optimized for a circle radius of the openings for matrices of 140 mm. In order to realize an even cutting, 12 openings for dies with a diameter of 23.8 mm on the circle radius of 140 mm could be used. Each die had 12 extrudate openings.

Per extrusion process, 144 extrudates could be produced.

Inventive Example 2:

For comparison, a device for dicing pasty molding compounds was constructed using the method of the invention, which was also optimized for a circle radius of the openings for matrices of 140 mm. In order to realize a uniform cutting, 12 openings for dies with a diameter of 23.8 mm on the circle radius of 140 mm could be used. In addition, another 12 holes for matrices could be used on another circle with a radius of 180 mm. Each die had 12 extrudate openings. Per extrusion process 288 extrudates could be produced.

Claims

claims 1. A method for dicing pasty molding materials using an extrusion device, wherein the molding materials are extruded through a plurality of openings on a die plate, characterized in that the extruded, pasty molding compositions are separated by one or more fluid films, wherein the Fluid film has a continuous volume flow with a parallel distribution over a distance of at least 5 cm, calculated from the origin of the fluid film. 2. The method according to claim 1, characterized in that the fluid film has a horizontal spread of 1 to 60 mm and a vertical spread of 0.1 to 20 mm. 3. The method according to claim 1 or 2, characterized in that the fluid film has a volume flow of 0.0001 to 50 Nm ³ / mm ² . 4. The method according to claims 1 to 3, characterized in that the fluid film has a temperature of -200 to 650 ⁰ C. 5. Process according to claims 1 to 4, characterized in that the fluid film is generated under a pressure of 1 to 100 bar. 6. Process according to claims 1 to 5, characterized in that the fluid film is formed perpendicular to the molding material extrudates. 7. The method according to claim 6, characterized in that the fluid film forms 0 to 100 mm above the die plate. 8. Process according to claims 1 to 7, characterized in that with a dicing process 5 to 800 mm ² extrudate mass is separated. 9. A device for dicing pasty molding compositions, comprising: an extrusion device having a die plate (3) with a plurality of extrudate openings (4) from which extruded molding compounds emerge through the openings, and with a fluid source in the center of the die plate is arranged, wherein the fluid exits through slit-like outlet openings (1) which are arranged in a circle on the fluid inflow pipe (5). 10. Apparatus according to claim 9, wherein 1 to 25 slot-like outlet openings are arranged on a circle with a diameter of 10 to 1000 mm. 2 figures 11. The device according to claims 9 or 10, wherein 1 to 50 matrices are arranged with 1 to 50 extrudate openings on the die plate.