EP0306865A1 - Mould for slip casting in the manufacture of shaped products of ceramic masses - Google Patents

Mould for slip casting in the manufacture of shaped products of ceramic masses Download PDF

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Publication number
EP0306865A1
EP0306865A1 EP19880114422 EP88114422A EP0306865A1 EP 0306865 A1 EP0306865 A1 EP 0306865A1 EP 19880114422 EP19880114422 EP 19880114422 EP 88114422 A EP88114422 A EP 88114422A EP 0306865 A1 EP0306865 A1 EP 0306865A1
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European Patent Office
Prior art keywords
pore
open
mold
carrier
slip casting
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EP19880114422
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German (de)
French (fr)
Inventor
Hans-Josef Dr. Sterzel
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BASF SE
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BASF SE
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    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B28—WORKING CEMENT, CLAY, OR STONE
    • B28B—SHAPING CLAY OR OTHER CERAMIC COMPOSITIONS; SHAPING SLAG; SHAPING MIXTURES CONTAINING CEMENTITIOUS MATERIAL, e.g. PLASTER
    • B28B1/00—Producing shaped prefabricated articles from the material
    • B28B1/26—Producing shaped prefabricated articles from the material by slip-casting, i.e. by casting a suspension or dispersion of the material in a liquid-absorbent or porous mould, the liquid being allowed to soak into or pass through the walls of the mould; Moulds therefor ; specially for manufacturing articles starting from a ceramic slip; Moulds therefor
    • B28B1/261—Moulds therefor

Definitions

  • the present invention relates to molds for the production of ceramic molded parts by means of the pressure slip casting process, where flowable slurries are injected into open-pore molds and the mold surface is designed in such a way that slurries with particle sizes of 0.1 to 2 ⁇ m expansion can be processed without difficulty.
  • slip is understood to mean slurrying of the ceramic powder in water or organic liquids.
  • surface-active substances such as organic surfactants or inorganic polyphosphates.
  • the flow behavior is adjusted in a desired manner by adding further additives, such as synthetic or natural polymers that are soluble in the liquid, such as polyacrylic acid, polyacrylamides or cellulose derivatives.
  • the aim is to set a high solids content with good flowability.
  • pressure slip casting was proposed as a new process.
  • the plaster mold is replaced by another molding material, namely open-pore sintered metal or open-pore plastic.
  • the slip is first slowly pumped into the closed mold, the inner wall of the mold holding back the ceramic powder and the suspension medium passing through the mold. If the inner wall of the mold is covered with a layer of ceramic powder, the conveying speed is increased and the molded part is built up in the mold in a layer filtration analogous to the filter cake. Because of the high filtration pressure, the cullet is built up in a much shorter time than in a plaster mold at normal pressure.
  • the mold When the conveyance of the slip to the mold comes to a standstill, the mold is filled.
  • the maximum delivery pressure is 40 - 60 bar.
  • the divisible mold is installed in a corresponding apparatus which is not the subject of this application.
  • the pressure is removed and a negative pressure is applied to one mold half in order to hold the molded body on this mold half.
  • the mold is then opened and the molded product is removed after the vacuum has been removed.
  • the mold halves are rinsed in the opposite direction with water.
  • the molds required for this process can be produced from porous sintered metal semi-finished products. For economic reasons, molds made from open-pore plastics are preferred (DOS 3 134 679). Plastic molds of this type are usually produced by foaming reactive resins. These reactive resins contain urethane and / or isocyanurate and / or urea bonds and are produced by foaming the corresponding components using conventional polyurethane technology.
  • starting powder with grain sizes in the range from 0.1 ⁇ m to 5 ⁇ m are used for the production of structural ceramic parts with high temperature resistance and high strengths based on aluminum oxide, zirconium dioxide, silicon nitride, silicon carbide, mullite, sialons or other powders for structural ceramic parts.
  • the pressure slip molds according to the prior art are no longer sufficient. It has also not yet been possible to produce reproducible shapes with duromer technology, the open pores of which have widths below 5 ⁇ m.
  • the mold has a two-layer structure with a mechanically stable open-pore carrier with large pore sizes and a thin open-pore separation layer with a small pore size on the inside of the mold.
  • the coarser-pored shape essentially serves as a support material, while the separation of ceramic powder and liquid runs on the additionally applied thin separation layer.
  • separating membranes can be used as separating layers, which are used in the areas of micro- and ultrafiltration.
  • Such membranes have thicknesses of up to 100 ⁇ m, consist of synthetic polymers and are produced by various processes (see Synthetic Membrane Production, Structure and Application, Angew. Chem. 94 (1982) 670-695).
  • Nuclepore-type membranes with pore sizes of 0.5 to 5 ⁇ m are produced by irradiating polycarbonate or polyester films with heavy ions and then etching the areas damaged by the passage of the particles. Pores with a particularly narrow size distribution are obtained.
  • monoaxially appropriate polymer films are stretched a second time perpendicular to the original stretching direction, slit-shaped to elliptical pores being created and pore sizes of 0.05 to 5 ⁇ m being able to be set.
  • Such membranes are available, for example, on the basis of polyethylene, polypropylene or polytetrafluoroethylene (Celgard, Goretex or Poreflon type).
  • Separating membranes can also be produced from partially crystalline polymers, such as polyethylene, polypropylene or polyamides, by dissolving the polymers in an organic solvent at elevated temperatures, knife-coating the solution into films and then allowing it to cool. On cooling, the polymer crystallizes out, leaving an open-pore structure that is filled by the solvent. After removing the solvent, there are separation membranes with pore sizes of 0.01 to 2 ⁇ m.
  • partially crystalline polymers such as polyethylene, polypropylene or polyamides
  • the membranes are manufactured using the phase inversion method.
  • the polymer is dissolved in an organic solvent, the solution is knife-coated onto a circulating conveyor belt, part of the solvent is allowed to evaporate and the conveyor belt is then passed into a bath with non-solvent, the polymer coagulating starting at the surface of the polymer / solvent film and goes into the solid phase.
  • the asymmetric membrane structure is created.
  • Molds according to the invention are produced by covering the large-pore starting forms with separating membranes of the desired pore sizes. Dry membranes made of hydrophobic polymers, such as polycarbonate, polyesters or polyolefins, are heated until they become correspondingly stretchable and pressed onto the starting shape with an air stream of the same temperature, also at the same temperature level. Membranes made of hydrophilic polymers, such as polyamides or cellulose derivatives, are applied to the starting form in a moist state at room temperature.
  • hydrophobic polymers such as polycarbonate, polyesters or polyolefins
  • asymmetrical membranes are produced directly on the surface of the starting form, with which the best adhesion properties are achieved.
  • the membrane polymer is dissolved in a water-soluble organic solvent, such as acetone, formamide or dimethylformamide or a solvent mixture in a concentration of 5 to 35% by weight, the viscous solution is degassed in vacuo and applied to the surface of the starting form. After a short evaporation time, the mold surface is sprayed with water and then immersed in water for about 10 minutes to develop the structure completely.
  • a water-soluble organic solvent such as acetone, formamide or dimethylformamide or a solvent mixture in a concentration of 5 to 35% by weight
  • the separating layers produced by the preferred method are so well anchored in the carrier material that they survive backwashing processes without detachment.
  • the molds according to the invention are also suitable for shaping with slip based on organic solvents. Separating layers based on polysulfone, polyether sulfone, polyetherimide or polyamides are stable against aromatic-free aliphatic hydrocarbons. Subsequent crosslinking of the membrane polymer further increases the solvent resistance.
  • membrane polymers with free amino or hydroxyl groups can be crosslinked by treatment with formaldehyde or epichlorohydrin.
  • the molds according to the invention are used to produce molded parts made of aluminum oxide, zirconium dioxide, mullite, sialons, silicon nitride, silicon carbide, titanium boride, boron carbide or boron nitride.

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  • Engineering & Computer Science (AREA)
  • Chemical & Material Sciences (AREA)
  • Ceramic Engineering (AREA)
  • Dispersion Chemistry (AREA)
  • Manufacturing & Machinery (AREA)
  • Mechanical Engineering (AREA)
  • Separation Using Semi-Permeable Membranes (AREA)
  • Producing Shaped Articles From Materials (AREA)

Abstract

A mould for the production of ceramic shaped products by means of slip casting has a two-layer structure with a mechanically stable, open-cell support with large pored widths, and a thinner, open-pore parting layer with a smaller pore width on the inner side of the mould.

Description

Die vorliegende Erfindung betrifft Formen zur Herstellung keramischer Formteile mittels des Druckschlickergießverfahrens, wobei fließfähige Schlicker in offenporige Formen eingespritzt werden und die Formoberfläche derart gestaltet ist, daß sich ohne Schwierigkeiten Schlicker mit Teilchengrößen von 0,1 bis 2 µm Ausdehnung verarbeiten lassen.The present invention relates to molds for the production of ceramic molded parts by means of the pressure slip casting process, where flowable slurries are injected into open-pore molds and the mold surface is designed in such a way that slurries with particle sizes of 0.1 to 2 μm expansion can be processed without difficulty.

Unter Schlicker versteht man in der keramischen Verfahrenstechnik Aufschlämmungen der keramischen Pulver in Wasser oder organischen Flüssigkeiten. Um gegenüber der Sedimentation stabile Schlicker zu erhalten, setzt man oberflächenaktive Stoffe, wie organische Tenside oder anorganische Polyphosphate in geringen Mengen zu. Gegebenenfalls wird das Fließverhalten durch Zusätze weiterer Additive, wie in der Flüssigkeit löslichen synthetischen oder natürlichen Polymeren, wie Polyacrylsäure, Polyacrylamide oder Cellulosederivaten in gewünschter Weise eingestellt.In ceramic process engineering, slip is understood to mean slurrying of the ceramic powder in water or organic liquids. In order to obtain slurries that are stable against sedimentation, small amounts of surface-active substances, such as organic surfactants or inorganic polyphosphates, are added. If necessary, the flow behavior is adjusted in a desired manner by adding further additives, such as synthetic or natural polymers that are soluble in the liquid, such as polyacrylic acid, polyacrylamides or cellulose derivatives.

Man ist bestrebt, einen hohen Feststoffgehalt bei guter Fließfähigkeit einzustellen.The aim is to set a high solids content with good flowability.

In der Keramikindustrie ist es üblich, derartige Schlicker in Gipsformen zu gießen, wobei nur der hydrostatische Druck wirkt. Aufgrund der Saugwirkung über die Kapillarkräfte des Gips wird Wasser in den Gips gesogen und das feste Formteil innerhalb der Form ausgebildet. Dieses Verfahren ist sehr zeitaufwendig und umständlich, weil die Gipsformen nur wenige Male oder gar nur einmal verwendet werden können und zum nächsten Gebrauch zeitaufwendig getrocknet werden müssen. Insgesamt lassen sich mit einer Gipsform nur wenige Abformungen durchführen.It is common in the ceramic industry to cast such slurries in plaster molds, with only the hydrostatic pressure acting. Due to the suction effect via the capillary forces of the plaster, water is sucked into the plaster and the solid molded part is formed within the mold. This process is very time-consuming and cumbersome because the plaster molds can only be used a few times or even once and have to be dried in a time-consuming manner for the next use. Overall, only a few impressions can be made with a plaster mold.

Zur Serienfertigung von Geschirr- und Sanitärteilen wurde als neues Verfahren der Druckschlickerguß vorgeschlagen. Dort wird die Gipsform durch ein anderes Formmaterial, nämlich offenporiges Sintermetall oder offenporigen Kunststoff ersetzt. Der Schlicker wird zunächst langsam in die geschlossene Form gepumpt, wobei die Forminnenwand das keramische Pulver zurückhält und das Suspensionsmittel die Form passiert. Wenn die Forminnenwand mit einer Schicht aus keramischem Pulver belegt ist, wird die Fördergeschwindigkeit erhöht und analog dem Filterkuchen in einer Schichtfiltration das Formteil in der Form aufgebaut. Wegen des hohen Filtrationsdrucks wird der Scherben in sehr viel kürzerer Zeit aufgebaut als in einer Gipsform bei Normaldruck.For the serial production of tableware and sanitary parts, pressure slip casting was proposed as a new process. There, the plaster mold is replaced by another molding material, namely open-pore sintered metal or open-pore plastic. The slip is first slowly pumped into the closed mold, the inner wall of the mold holding back the ceramic powder and the suspension medium passing through the mold. If the inner wall of the mold is covered with a layer of ceramic powder, the conveying speed is increased and the molded part is built up in the mold in a layer filtration analogous to the filter cake. Because of the high filtration pressure, the cullet is built up in a much shorter time than in a plaster mold at normal pressure.

Wenn die Förderung des Schlickers zur Form zum Stillstand kommt, ist die Form gefüllt. Der maximale Förderdruck beträgt 40 - 60 bar. Um die notwendige Formschließkraft aufbringen zu können, wird die teilbare Form in eine entsprechende apparative Vorrichtung eingebaut, die nicht Gegen­stand dieser Anmeldung ist.When the conveyance of the slip to the mold comes to a standstill, the mold is filled. The maximum delivery pressure is 40 - 60 bar. In order to be able to apply the necessary mold clamping force, the divisible mold is installed in a corresponding apparatus which is not the subject of this application.

Vor dem Ausformen wird der Druck weggenommen und an einer Formhälfte ein Unterdruck angelegt, um den Formkörper an dieser Formhälfte zu halten. Danach wird die Form geöffnet und nach Wegnahme des Unterdrucks der Formling entnommen.Before molding, the pressure is removed and a negative pressure is applied to one mold half in order to hold the molded body on this mold half. The mold is then opened and the molded product is removed after the vacuum has been removed.

Zur Entfernung von Schlickerresten aus den Poren der Form und zur Säuberung der Formoberfläche werden die Formhälften in Gegenrichtung mit Wasser gespült.To remove slip residues from the pores of the mold and to clean the mold surface, the mold halves are rinsed in the opposite direction with water.

Die für dieses Verfahren benötigten Formen lassen sich aus porösen Sintermetallhalbzeugen herstellen. Aus wirtschaftlichen Gründen werden Formen aus offenporigen Kunststoffen bevorzugt (DOS 3 134 679). Derartige Kunststoffformen werden üblicherweise durch Schäumen von Reaktionsharzen hergestellt. Diese Reaktionsharze enthalten Urethan und/oder Isocyanurat und/oder Harnstoff-Bindungen und werden durch Schäumen der entsprechenden Komponenten nach üblicher Polyurethantechnologie hergestellt.The molds required for this process can be produced from porous sintered metal semi-finished products. For economic reasons, molds made from open-pore plastics are preferred (DOS 3 134 679). Plastic molds of this type are usually produced by foaming reactive resins. These reactive resins contain urethane and / or isocyanurate and / or urea bonds and are produced by foaming the corresponding components using conventional polyurethane technology.

Es handelt sich dabei um hochvernetzte offenporige Duromerschäume. Danach lassen sich Formen mit Porenweiten größer als 10 µm erzeugen.These are highly cross-linked open-pore duromer foams. Then shapes with pore sizes larger than 10 µm can be created.

Formen mit derartigen Porenweiten erfüllen weitgehend die Anforderungen an den Druckschlickerguß von Sanitär- und Geschirrteilen, weil die keramischen Ausgangspulver für derartige Teile Korngrößen von mehr als 10 µm aufweisen.Molds with such pore sizes largely meet the requirements for pressure slip casting of sanitary and crockery parts because the ceramic starting powders for such parts have grain sizes of more than 10 μm.

Demgegenüber werden für die Herstellung strukturkeramischer Teile mit hoher Temperaturbeständigkeit bei gleichzeitig hohen Festigkeiten auf der Basis von Aluminiumoxid, Zirkondioxid, Siliciumnitrid, Siliciumcarbid, Mullit, Sialonen oder anderen Pulvern für strukturkeramische Teile Ausgangspulver mit Korngrößen im Bereich von 0,1 µm bis 5 µm eingesetzt. Für derartige Pulver genügen die Druckschlickergußformen nach dem Stand der Technik nicht mehr. Es ist auch bisher noch nicht gelungen, mit der Duromertechnologie reproduzierbare Formen herzustellen, deren offene Poren Weiten unterhalb von 5 µm aufweisen.In contrast, starting powder with grain sizes in the range from 0.1 µm to 5 µm are used for the production of structural ceramic parts with high temperature resistance and high strengths based on aluminum oxide, zirconium dioxide, silicon nitride, silicon carbide, mullite, sialons or other powders for structural ceramic parts. For such powders, the pressure slip molds according to the prior art are no longer sufficient. It has also not yet been possible to produce reproducible shapes with duromer technology, the open pores of which have widths below 5 µm.

Es war demnach Aufgabe der vorliegenden Erfindung, Druckschlickergußformen bereitzustellen, die an der Forminnenseite Porenweiten unterhalb 5 µm, vorzugsweise im Bereich von 0,05 bis 2 µm aufweisen, um die Druck­schlickergußverarbeitung von Schlickern mit Teilchengrößen von 0,1 bis 5 µm zu ermöglichen.It was therefore an object of the present invention to provide pressure slip casting molds which have pore widths below 5 μm on the inside of the mold, preferably in the range from 0.05 to 2 μm in order to enable pressure slip casting processing of slurries with particle sizes from 0.1 to 5 μm.

Diese Aufgabe wird erfindungsgemäß dadurch gelöst, daß die Form einen Zweischichtenaufbau aufweist mit einem mechanisch stabilen offenporigen Träger mit großen Porenweiten und einer dünnen offenporigen Trennschicht geringer Porenweite auf der Forminnenseite. Dabei dient die gröberporige Form im wesentlichen als Stützmaterial, während die Trennung von keramischem Pulver und Flüssigkeit an der zusätzlich aufgebrachten dünnen Trennschicht verläuft.This object is achieved in that the mold has a two-layer structure with a mechanically stable open-pore carrier with large pore sizes and a thin open-pore separation layer with a small pore size on the inside of the mold. The coarser-pored shape essentially serves as a support material, while the separation of ceramic powder and liquid runs on the additionally applied thin separation layer.

Als Trennschichten lassen sich handelsübliche synthetische Trennmembranen einsetzen, die in den Bereichen der Mikro- und Ultrafiltration Anwendung finden. Derartige Membranen haben Dicken bis zu 100 µm, bestehen aus synthetischen Polymeren und werden nach verschiedenen Verfahren hergestellt (s. Synthetische Membranen-Herstellung, Struktur und Anwendung, Angew. Chem. 94 (1982) 670-695).Commercially available synthetic separating membranes can be used as separating layers, which are used in the areas of micro- and ultrafiltration. Such membranes have thicknesses of up to 100 μm, consist of synthetic polymers and are produced by various processes (see Synthetic Membrane Production, Structure and Application, Angew. Chem. 94 (1982) 670-695).

Membranen von Nuclepore-Typ mit Porenweiten von 0,5 bis 5 µm werden hergestellt, indem man Filme aus Polycarbonat oder Polyestern mit schweren Ionen bestrahlt und anschließend die durch den Teilchendurchgang geschädigten Stellen ätzt. Dabei werden Poren mit besonders enger Größenverteilung erhalten.Nuclepore-type membranes with pore sizes of 0.5 to 5 μm are produced by irradiating polycarbonate or polyester films with heavy ions and then etching the areas damaged by the passage of the particles. Pores with a particularly narrow size distribution are obtained.

Nach einem weiteren Verfahren werden monoaxial gerechte Polymerfilme ein zweites Mal senkrecht zur ursprünglichen Reckrichtung verstreckt, wobei schlitzförmige bis elliptische Poren entstehen und Porenweiten von 0,05 bis 5 µm eingestellt werden können. Derartige Membranen sind beispielsweise auf der Basis von Polyethylen, Polypropylen oder Polytetrafluorethylen erhältlich (Celgard-, Goretex- oder Poreflon-Typ).According to a further process, monoaxially appropriate polymer films are stretched a second time perpendicular to the original stretching direction, slit-shaped to elliptical pores being created and pore sizes of 0.05 to 5 μm being able to be set. Such membranes are available, for example, on the basis of polyethylene, polypropylene or polytetrafluoroethylene (Celgard, Goretex or Poreflon type).

Weiterhin lassen sich Trennmembranen aus teilkristallinen Polymeren, wie Polyethylen, Polypropylen oder Polyamiden herstellen, indem man die Polymeren in einem organischen Lösungsmittel bei erhöhten Temperaturen löst, die Lösung zu Folien ausrakelt und dann erkalten läßt. Beim Erkalten kristallisiert das Polymere aus und hinterläßt eine offenporige Struktur, die vom Lösungsmittel ausgefüllt wird. Nach Entfernen des Lösungsmittels liegen Trennmembranen mit Porenweiten von 0,01 bis 2 µm vor.Separating membranes can also be produced from partially crystalline polymers, such as polyethylene, polypropylene or polyamides, by dissolving the polymers in an organic solvent at elevated temperatures, knife-coating the solution into films and then allowing it to cool. On cooling, the polymer crystallizes out, leaving an open-pore structure that is filled by the solvent. After removing the solvent, there are separation membranes with pore sizes of 0.01 to 2 µm.

Meistens werden synthetische Trennmembranen mit asymmetrischem Dicken­aufbau eingesetzt. Diese Membranen weisen eine feinporige Deckschicht, die eigentliche Trennschicht mit Dicken von 0,2 bis 2 µm auf, an die sich eine großporige Stützschicht mit 50 bis 500 µm Dicke anschließt.Mostly synthetic separation membranes with an asymmetrical thickness structure are used. These membranes have a fine-pored cover layer, the actual separating layer with a thickness of 0.2 to 2 µm, followed by a large-pore support layer with a thickness of 50 to 500 µm.

Die Membranen werden nach dem Verfahren der Phaseninversion hergestellt. Dabei löst man das Polymere in einem organischen Lösungsmittel, rakelt die Lösung auf ein umlaufendes Transportband, läßt einen Teil des Lösungs­mittels verdampfen und leitet dann das Transportband in ein Bad mit Nichtlösungsmittel, wobei das Polymere an der Oberfläche des Polymer/­Lösungsmittel-Films beginnend koaguliert und in die feste Phase übergeht. Als Folge der Polymerkoagulation, überlagert vom Austausch von Lösungs­mittel durch Fällungsmittel, entsteht die asymmetrische Membranstruktur.The membranes are manufactured using the phase inversion method. The polymer is dissolved in an organic solvent, the solution is knife-coated onto a circulating conveyor belt, part of the solvent is allowed to evaporate and the conveyor belt is then passed into a bath with non-solvent, the polymer coagulating starting at the surface of the polymer / solvent film and goes into the solid phase. As a result of polymer coagulation, overlaid by the exchange of solvent with precipitant, the asymmetric membrane structure is created.

Formen nach der Erfindung werden hergestellt, indem man die großporigen Ausgangsformen mit Trennmembranen der gewünschten Porengrößen belegt. Trockene Membranen aus hydrophoben Polymeren, wie Polycarbonat, Polyestern oder Polyolefinen werden dazu soweit erhitzt bis sie entsprechend dehnbar werden und mit einem Luftstrom gleicher Temperatur auf die Ausgangsform, ebenfalls auf gleichem Temperaturniveau befindlich, angedrückt. Membranen aus hydrophilen Polymeren, wie Polyamiden oder Cellulosederivaten werden in feuchtem Zustand bei Raumtemperatur auf die Ausgangsform aufgebracht.Molds according to the invention are produced by covering the large-pore starting forms with separating membranes of the desired pore sizes. Dry membranes made of hydrophobic polymers, such as polycarbonate, polyesters or polyolefins, are heated until they become correspondingly stretchable and pressed onto the starting shape with an air stream of the same temperature, also at the same temperature level. Membranes made of hydrophilic polymers, such as polyamides or cellulose derivatives, are applied to the starting form in a moist state at room temperature.

Nach einem bevorzugten Verfahren werden asymmetrische Membranen direkt auf der Oberfläche der Ausgangsform erzeugt, womit die besten Haftungs­eigenschaften erzielt werden.According to a preferred method, asymmetrical membranes are produced directly on the surface of the starting form, with which the best adhesion properties are achieved.

Dazu wird das Membranpolymere in einem wasserlöslichen organischen Lösungsmittel, wie Aceton, Formamid oder Dimethylformamid oder Lösungsmittelgemisch in einer Konzentration von 5 bis 35 Gew.-% gelöst, die viskose Lösung im Vakuum entgast und auf die Oberfläche der Ausgangs­form aufgestrichen. Nach einer kurzen Verdunstungszeit wird die Form­oberfläche mit Wasser besprüht und dann ca. 10 Min. zur vollständigen Strukturentwicklung in Wasser eingetaucht.For this purpose, the membrane polymer is dissolved in a water-soluble organic solvent, such as acetone, formamide or dimethylformamide or a solvent mixture in a concentration of 5 to 35% by weight, the viscous solution is degassed in vacuo and applied to the surface of the starting form. After a short evaporation time, the mold surface is sprayed with water and then immersed in water for about 10 minutes to develop the structure completely.

Die nach dem bevorzugten Verfahren hergestellten Trennschichten sind derart gut im Trägermaterial verankert, daß sie Rückspülvorgänge ohne Ablösung überstehen.The separating layers produced by the preferred method are so well anchored in the carrier material that they survive backwashing processes without detachment.

Durch die Wahl geeigneter Membranpolymerer sind die erfindungsgemäßen Formen auch zur Formgebung mit Schlickern auf Basis organischer Lösungs­mittel geeignet. Trennschichten auf der Basis von Polysulfon, Polyether­sulfon, Polyetherimid oder Polyamiden sind stabil gegen aromatenfreie aliphatische Kohlenwasserstoffe. Durch nachträgliche Vernetzung des Membranpolymeren wird die Lösungsmittelbeständigkeit weiter erhöht. So lassen sich beispielsweise Membranpolymere mit freien Amino- oder Hydroxylgruppen durch Behandlung mit Formaldehyd oder Epichlorhydrin vernetzen.By selecting suitable membrane polymers, the molds according to the invention are also suitable for shaping with slip based on organic solvents. Separating layers based on polysulfone, polyether sulfone, polyetherimide or polyamides are stable against aromatic-free aliphatic hydrocarbons. Subsequent crosslinking of the membrane polymer further increases the solvent resistance. For example, membrane polymers with free amino or hydroxyl groups can be crosslinked by treatment with formaldehyde or epichlorohydrin.

Die erfindungsgemäßen Formen dienen zur Herstellung von Formteilen aus Aluminiumoxid, Zirkondioxid, Mullit, Sialonen, Siliciumnitrid, Siliciumcarbid, Titanborid, Borcarbid oder Bornitrid.The molds according to the invention are used to produce molded parts made of aluminum oxide, zirconium dioxide, mullite, sialons, silicon nitride, silicon carbide, titanium boride, boron carbide or boron nitride.

Claims (6)

1. Form zur Herstellung keramischer Formteile mittels Druckschlickerguß, dadurch gekennzeichnet, daß sie einen Zweischichtenaufbau aufweist mit einem mechanisch stabilen offenporigen Träger mit großen Porenweiten und einer dünneren offenporigen Trennschicht geringer Porenweite auf der Forminnenseite.1. Mold for the production of ceramic moldings by means of pressure slip casting, characterized in that it has a two-layer structure with a mechanically stable open-pore carrier with large pore sizes and a thinner open-pore separating layer with a small pore size on the inside of the mold. 2. Form nach Anspruch 1, dadurch gekennzeichnet, daß die dünne offen­porige Trennschicht mit geringer Porenweite aus Mikro- oder Ultra­filtrationstrennmembranen besteht.2. Mold according to claim 1, characterized in that the thin open-pore separation layer with a small pore size consists of micro- or ultrafiltration separation membranes. 3. Form nach Anspruch 1, dadurch gekennzeichnet, daß die dünne offen­porige Trennschicht auf dem offenporigen Träger großer Porenweite nach dem Phaseninversionsverfahren, d.h. Auftragen einer Polymerlösung und Koagulation des Polymer/Lösungsmittelfilms durch Berührung mit einem Nichtlösungsmittel, direkt erzeugt wird.3. Mold according to claim 1, characterized in that the thin open-pore separation layer on the open-pore carrier of large pore size by the phase inversion process, i.e. Application of a polymer solution and coagulation of the polymer / solvent film by contact with a non-solvent is generated directly. 4. Form nach den Ansprüchen 1 bis 3, dadurch gekennzeichnet, daß der offenporige Träger Porenweiten oberhalb 5 µm aufweist und die dünne offenporige Trennschicht bei Dicken von 50 bis 1 000 µm Porenweiten von 0,01 bis 2 µm aufweist.4. Mold according to claims 1 to 3, characterized in that the open-pore carrier has pore sizes above 5 microns and the thin open-pore separating layer has thicknesses of 50 to 1,000 microns pore sizes of 0.01 to 2 microns. 5. Form nach den Ansprüchen 1 bis 4, dadurch gekennzeichnet, daß der offenporige Träger aus einem organisch vernetzten Reaktionsharz besteht.5. Form according to claims 1 to 4, characterized in that the open-pore carrier consists of an organically crosslinked reaction resin. 6. Form nach den Ansprüchen 1 bis 4, dadurch gekennzeichnet, daß der offenporige Träger durch Sintern von Metallpulver hergestellt wurde.6. Mold according to claims 1 to 4, characterized in that the open-pore carrier was produced by sintering metal powder.
EP19880114422 1987-09-08 1988-09-03 Mould for slip casting in the manufacture of shaped products of ceramic masses Withdrawn EP0306865A1 (en)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
DE3730024 1987-09-08
DE19873730024 DE3730024A1 (en) 1987-09-08 1987-09-08 MOLDING FOR PRINTING SLICK CASTING FOR PRODUCING MOLDED PARTS FROM CERAMIC MEASURES

Publications (1)

Publication Number Publication Date
EP0306865A1 true EP0306865A1 (en) 1989-03-15

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EP19880114422 Withdrawn EP0306865A1 (en) 1987-09-08 1988-09-03 Mould for slip casting in the manufacture of shaped products of ceramic masses

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EP (1) EP0306865A1 (en)
JP (1) JPS6471705A (en)
DE (1) DE3730024A1 (en)

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DE4233272A1 (en) * 1991-10-04 1993-04-08 Ngk Insulators Ltd Ceramic connection casting for mfg. e.g. exhaust opening - using structured pressures to extract water in sludge at mould
DE19854258A1 (en) * 1998-11-25 2000-05-31 Univ Ilmenau Tech Pressure casting tool for shaping ceramics has coating on inner surface of tool forming mold volume that maintains pores open and hence filtration characteristics of tool
WO2006056192A2 (en) * 2004-11-25 2006-06-01 Dorst Technologies Gmbh Co. Kg Casting mold, especially diecasting mold, method for producing the same and method for low pressure diecasting
DE102007045806A1 (en) 2007-09-25 2009-04-02 Dorst Technologies Gmbh & Co. Kg Molded component, particularly compressed molded component, has base layer that is made of base layer material of firmly connected pieces, and base layer material has base layer permeability that is dimensioned for conducting fluid
EP2216150A2 (en) 2009-02-05 2010-08-11 Dorst Technologies GmbH & Co. KG Casting mould components and casting mould

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JP2001313493A (en) * 2000-04-27 2001-11-09 Sony Corp System for mounting electronic component
DE102005007909A1 (en) * 2005-02-08 2006-08-10 Rennebeck, Klaus, Dr. Manufacturing device for molded ceramic parts has at least one part of the mold made so that fluid can enter and leave through several apertures
DE102011117764B4 (en) 2011-11-07 2015-02-05 Technische Universität Bergakademie Freiberg Druckschlickergießverfahren for deagglomerierte slip based on ceramic, metallo-ceramic or metallic powder with particle sizes in the range of 20 nm to 50 microns

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DE3342823A1 (en) * 1983-11-26 1985-06-05 Seitz-Filter-Werke Theo & Geo Seitz GmbH und Co, 6550 Bad Kreuznach METHOD FOR PRODUCING FILTER ELEMENTS BASED ON AROMATIC POLYAMIDE

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GB661780A (en) * 1949-03-28 1951-11-28 Sintered Products Ltd Improvements in or relating to moulds
DE2808222A1 (en) * 1978-02-25 1979-08-30 Battelle Institut E V METHOD FOR MANUFACTURING COMPOSITE MEMBRANES
DE3118924A1 (en) * 1980-05-15 1982-04-08 Asahi Kasei Kogyo K.K., Osaka POROESE MEMBRANE MADE OF THERMOPLASTIC RESIN AND METHOD FOR THEIR PRODUCTION
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DE3342823A1 (en) * 1983-11-26 1985-06-05 Seitz-Filter-Werke Theo & Geo Seitz GmbH und Co, 6550 Bad Kreuznach METHOD FOR PRODUCING FILTER ELEMENTS BASED ON AROMATIC POLYAMIDE

Cited By (9)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE4233272A1 (en) * 1991-10-04 1993-04-08 Ngk Insulators Ltd Ceramic connection casting for mfg. e.g. exhaust opening - using structured pressures to extract water in sludge at mould
US5474724A (en) * 1991-10-04 1995-12-12 Ngk Insulators, Ltd. Method for molding a ceramic port liner
DE4233272C2 (en) * 1991-10-04 1998-12-24 Ngk Insulators Ltd Process for casting a ceramic connector trim element
DE19854258A1 (en) * 1998-11-25 2000-05-31 Univ Ilmenau Tech Pressure casting tool for shaping ceramics has coating on inner surface of tool forming mold volume that maintains pores open and hence filtration characteristics of tool
WO2006056192A2 (en) * 2004-11-25 2006-06-01 Dorst Technologies Gmbh Co. Kg Casting mold, especially diecasting mold, method for producing the same and method for low pressure diecasting
WO2006056192A3 (en) * 2004-11-25 2006-08-24 Dorst Technologies Gmbh Co Kg Casting mold, especially diecasting mold, method for producing the same and method for low pressure diecasting
DE102007045806A1 (en) 2007-09-25 2009-04-02 Dorst Technologies Gmbh & Co. Kg Molded component, particularly compressed molded component, has base layer that is made of base layer material of firmly connected pieces, and base layer material has base layer permeability that is dimensioned for conducting fluid
EP2216150A2 (en) 2009-02-05 2010-08-11 Dorst Technologies GmbH & Co. KG Casting mould components and casting mould
DE102009007670A1 (en) 2009-02-05 2010-08-12 Dorst Technologies Gmbh & Co. Kg Mold component, mold and use of such a mold

Also Published As

Publication number Publication date
JPS6471705A (en) 1989-03-16
DE3730024A1 (en) 1989-03-16

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