EP2342375A1

EP2342375A1 - Process and device for manufacturing shaped composite, the shaped composite and the shaped inorganic article derived from it

Info

Publication number: EP2342375A1
Application number: EP09775795A
Authority: EP
Inventors: Yoram De Hazan; Thomas Graule; Paul Gregor Mueller
Original assignee: Eidgenoessische Materialprufungs und Forschungsanstalt EMPA; EMPA
Current assignee: Eidgenoessische Materialprufungs und Forschungsanstalt EMPA; EMPA
Priority date: 2008-10-07
Filing date: 2009-10-07
Publication date: 2011-07-13
Also published as: WO2010040243A1; WO2010040243A4

Abstract

The present invention relates to processes for manufacturing shaped composites as defined in the specification; to processes for manufacturing shaped inorganic articles; to manufacturing devices suitable for such processes; to shaped composites, shaped inorganic articles and to the use of the processes and manufacturing devices as described herein.

Description

PROCESS AND DEVICE FOR MANU FACTURING SHAPED COMPOSITE , THE SHAPED COMPOSITE AND THE SHAPED INORGANIC ARTICLE DERIVED FROM IT .

The present invention relates to processes for manufacturing shaped composites; to processes for 5 manufacturing shaped inorganic articles; to manufacturing devices suitable for such processes; to shaped compos^¬ ites, shaped inorganic articles and to the use of the processes and manufacturing devices as described herein. 0 Jeong et al (Lab Chip, 2004, 4, 576-580) dis^¬ close a process for manufacturing micro-scale polymer fibres and polymer tubes not including inorganic particles. EP 1577427 discloses a process for manufacturing fibres containing only organic carbon particles and not5 containing inorganic particles; the corresponding manufacturing process makes no use of a sheath and is restricted to the use of tapered dies.

The processes known so far are somehow lim-0 ited to the starting materials used; are considered unsuitable for large scale production; are considered unsuitable for production of small structures; do not control the microstructure of the articles produced. 5 In consequence, there is an ever existing need for improved manufacturing processes, manufacturing devices for such processes and new products.

Thus, it is an object of the present inven-0 tion to mitigate at least some of these drawbacks of the state of the art. In particular, it is an aim of the present invention to provide a versatile process for the production of shaped composites and shaped inorganic articles. 5

These objectives are achieved by a process as defined in claim 1 and manufacturing devices as defined in claim 18 and 20. Further aspects of the invention are disclosed in the specification and independent claims, preferred embodiments are disclosed in the specification and the dependent claims. Processes as described herein, particularly using the specific starting materials, prove to be useful for the manufacture of shaped composites and shaped articles as defined below.

The present invention will be described in more detail below. It is understood that the various embodiments, preferences and ranges as provided / disclosed in this specification may be combined at will. Further, depending of the specific embodiment, selected definitions, embodiments or ranges may not apply.

As it will become apparent when reading this specification, the invention relates

^■ in a first aspect to a process for manufacturing shaped composites; ■ in a second aspect to a process for manufacturing shaped inorganic articles;

^■ in a third aspect to specific manufacturing devices;

^■ in a fourth aspect to new shaped composites / articles; " in a fifth aspect to uses of the processes, manufactur- ing devices and articles disclosed herein.

Further, the composites and articles obtainable according to the processes described herein may contain a structured surface and/or cross section, i.e. they are either structured or non-structured. Further, the composites and articles obtainable according to the processes described herein may consist of one material

(i.e. homogeneous through a cross - sectional profile) or more than one material (i.e. non-homogeneous through a cross - sectional profile) . The inventive processes as described herein thus produce ^■ unstructured and homogeneous shaped composites / articles, or

^■ unstructured and heterogeneous shaped composites / articles, or ■ structured and homogeneous shaped composites / articles, or

^■ structured and heterogeneous shaped composites / articles .

It is believed that the manufacturing process described herein is useful and can in particular be extended to the production of multicomponent polymer/ceramic and polymer/metal composites, ceramic, glass and metalic tubes, fibers and microstructured fibers.

The present invention will be better understood by reference to the figures; which are briefly explained below. In each case, the units / terms shown in brackets are optional

Fig. 1 shows a general and schematic process scheme according to the invention.

Fig. 2 shows in a general and schematic way cross-sections of composites / articles available by the inventive process; wherein in the first line a) shows a simple (i.e. unstructured and homogeneous composite / article; b) shows an unstructured heterogeneous composite / article; c) shows a structured homogeneous composite / article; d) shows a structured and heterogeneous composite / article; in the first line c) and d) show cross sections available by mechanical (hydrodynamic) structuring combined with lithographical structuring, in the second line cross-sections available by mechanical (hydrodynamic) structuring only are shown; in the third line cross-sections available by lithographical structuring only are shown. It should be particularly noted that the structuring shown is schematic.

Fig. 3 schematically shows a setup of a manufacturing device according to one embodiment of the invention, suitable for manufacturing simple shaped composites / articles. Fig. 3 (a) shows a set-up for dynamic sheathing, Fig. 3 (b) shows a setup for pseudo- static sheathing.

Fig. 4 schematically shows a setup of a manu- facturing device according to a further embodiment of the invention, suitable for manufacturing heterogeneous and structured shaped composites / articles. In this particular embodiment, a structuring liquid and a second dispersion in addition to a first dispersion are supplied to the die. The manufacturing of heterogeneous shaped composites / articles is preferred in combination with pseudo-static sheathing.

Fig. 5 schematically shows a setup of a manufacturing device according to a further embodiment of the invention, suitable for manufacturing structured shaped composites / articles. Fig. 5 (a) shows a set-up using a mask/shutter equipment, while Fig. 5 (b) shows a setup using a laser/focused beam. Such structuring is preferred in combination with dynamic sheathing as depicted in Fig. 3a) .

Fig. 6 schematically shows a setup of a manufacturing device according to a further embodiment of the invention ("deposition device") . Such device is suitable for manufacturing three dimensional random network structures ("non-wovens") as well as predetermined three dimensional structures (known from the field of rapid prototyping, such as direct write robocasting and free form fabrication) . Thus, supported articles comprising a substrate and a shaped three dimensional composite or inorganic material are obtainable by the inventive process. Self supported three dimensional articles are obtained after removal of the support. This figure shows the additional substrate (S) and the movement thereof relative to the exit die.

Unless otherwise stated, the following defi- nitions shall apply in this specification:

The term "shaped composite" defines a material obtainable or obtained by a process as disclosed herein, said material contains a cured polymer (as defined herein) and inorganic particles (as defined herein) .

The term "shaped inorganic article" defines an article consisting of one or more inorganic particles and which is essentially free of the cured polymer. The article may be sintered to full or close to full density of all or part of the inorganic constituents. The term "inorganic" is understood in its broadest sense. Thus, any material free of organic compounds, which is material containing C-C single or multiple bonds or C-H bonds, is considered "inorganic". Thus, the term inorganic refers to ceramics (oxides, carbides, nitrides, borides, silicates) , glasses (oxides, fluorides, calcogenides) , metals and alloys, inorganic salts and minerals (like nitrates, carbonates, sulphates, phosphates etc.). Preferred are ceramic, glass and metal particles. Particularly pre- ferred inorganic articles are ceramic articles. Said article may contain one single type of particles (i.e. one oxide, one salt, one metal, one alloy) or combinations of one or more of such particles.

The term "extrusion process" is known in the field; it defines a process to create composites of a fixed cross-sectional profile. This process is conventionally performed by pushing or drawing an appropriate material through a die of the desired cross section, optionally followed by one or more finishing steps. The term "co-extrusion" is known in the field; it refers to the process of simultaneously combining a first liquid and one or more additional liquids in one extrusion unit. The cross section of the stream may vary depending of application. In a broad sense, the additional liquid may be any suitable liquid and may comprise curable monomers, oligomers and/or polymers, dispersions of inorganic particles in these mixtures or inert liquids. For the avoidance of doubt, a sheathing fluid, in the context of this invention, is not considered an "additional liquid", thus the mere use of a sheathing fluid in a process according to this invention is not considered a "co- extrusion".

The terms "heterogeneous / homogeneous" define the compositions of the composite / article produced along a cross-section. If only one type of material is present, such composite / article is termed homogeneous, otherwise heterogeneous. Heterogeneous composites / articles may be "core/shell" type or "layered" and are preferably obtainable by co-extrusion.

The term "unstructured" refers to either homogeneous or heterogeneous composite / article produced in a process without structuring liquids where the whole of the composite (both cross section and length) is cured during the curing step.

The term "structured" defines the modified cross sectional shape of the composite / article produced relative to an unstructured composite / article. A modification of the cross section using structuring liquids is considered (hydrodynamic) structuring while a modification of the cross section using a complex die is considered (mechanical) structuring. A modification of the cross section using a complex die which is aided with structuring liquids is considered a combined mechanic - hydrodynamic structuring. The non-curable structuring liquids are fugitive after curing whereas the curable liquids are fugitive during debinding. Due to the radia- tion curing inherent to the present invention, (lithographic) structuring can also be done using focused beams (e.g. laser beams) or alternatively with a flood exposure radiation source equipped with a mask and a shutter. Sections of the curable extruded streams can be therefore selectively cured, producing modified cross sections. Structured articles are preferably above 10 micrometers in their larger dimension, particularly above 100 micrometers. In another embodiment the sectioning can be done along the direction of flow, producing thin cured sections (e.g. as a result of a shutter opening and closing or a focused beam with periodic motion) . The term "dispersion" is known in the field; it particularly refers to i) a system in which finely divided particles, which are approximately 1 nanometer to 0.1 micrometer in size, are dispersed within a continuous medium, which is a liquid, in a manner that prevents them from being filtered easily or settled rapidly ("nanopar- ticulate dispersion"); ii) a system in which finely divided particles, which are approximately 1 nanometer to 1 micrometer in size, are dispersed within a continuous medium, which is a liquid, ("colloidal dispersion") ; to a system in which particles, which are larger than about 1 micrometer in size, are distributed in a continuous medium, which is a liquid, which filtered easily but settle slowly ("suspension") . Since nanoparticulate dispersions, colloidal dispersions and suspensions are suitable for the present invention, the term "dispersion" is used to cover all types. Preferred are, however, dispersions of particles in the size range 1 nanometers - 10 micrometers. More preferably 10 nanometers - 1 micrometers . The term "fluid" is known in the field; it particularly includes liquids and gases, preferably liquids .

The term "liquid" as used herein includes solvents and dispersions, but excludes molten polymers (which are considered a "melt") .

The term "sheathing fluid" defines a stream of non curable fluid (preferably non-curable liquid) encompassing the extruded stream during the extrusion step and/or radiation curing step. In case of a dynamic sheath, such non-curable fluid may be a liquid or gas, but not molten polymer. In case of a pseudostatic sheath, such non-curable fluid may be a bath of liquid. Preferably, the sheathing fluid has limited miscibility with the dispersion. The sheathing fluid as defined herein does not harden (solidify) the dispersion by physical, chemical or other means (e.g. by coagulation) . As such, the sheathing fluids are termed non-coagulating with respect to the dispersions. For avoidance of doubt, the sheathing fluids themselves are not hardened during any of the processing steps. The primary intents of the sheath are prevention of the sticking of the cured composite to the wall of the curing vessel and sustaining a continuous flow due to surface tension and viscosity effects. The sheaths flow and viscosity provide also hydrodynamic means to modify the size of dispersion cross section but not intentionally the shape of the cross section before or during curing. If the sheath is present in the exit die of the dispersion, the sheath moves relative to the die and is referred to as "dynamic sheath". In one embodiment, given a radiation transparent die material and a suitable die design, the dynamic sheath enables the curing step to be performed in the die. In the case where the uncured extrudate is extruded through the exit die into a large reservoir of liquid the sheath is referred to as "pseudostatic sheath". This process generally avoids the use of dynamic sheathing fluid and can be adapted for mass production purposes. The curing step is done within the pseudostatic sheath reservoir. This requires radiation lamps providing flood exposure situated around the reservoir as well as reservoir materials transparent to electromagnetic radiation (e.g. UV) and sheathing fluid. In the context of the present invention, the sheathing fluid (particularly a sheathing liquid) is inert, i.e. it does not (or essentially not) chemically or physically react with other liquids present (excluding solubility and flow related effects) . Particularly, the sheathing fluid (sheathing liquid) does not or essentially not coagulate/precipitate or, in more general terms, does not solidify the other liquids present or is solidified by them.

The additional fluid relevant in the context of this invention are described below; it is further understood that the additional liquids are mutually non- coagulating (or essentially non-coagulating) with respect to first dispersion as defined below and sheathing fluid(s) .

The term "curing" in the context of the present invention refers to a hardening of the dispersion by initiating a chemical reaction which causes polymerisation and/or cross linking reactions of monomers, oligomers and/or polymers present in said dispersion. Such chemical reaction includes radical polymerisation. Such chemical reactions are considered an essential element of the inventive process. The inventive process 'relies on relatively low viscosity dispersions in a monomer rich composition. It is known that such reactions can be thermally initiated. However, in the present invention, where fast and controllable curing is desirable, curing by electromagnetic radiation, for example radiation in the ultraviolet (UV) and visible spectrum, is preferred. E-beam radiation is also considered electromagnetic radiation in the context of the present invention. Other forms of hardening, such as physical coagulation result- ing from solvent exchange, phase separation or precipitation (i.e. in wet spinning processes) are not considered curing. In addition, processes involving hardening by or during a drying step (i.e. in dry spinning processes) are not considered curing. Hardening by curing has several advantages. It enables the use of new feedstock materials (both components i and ii) , particularly of monomer rich feedstock materials and a variety of dispersed inorganic particles. The use of such radiation curable monomer as diluent avoids the use of solvents and enables dispersions of high solids loading (component i) having comparatively low viscosity. Such feedstock leads also to composite and inorganic products having new properties (e.g. crosslinked polymer phase), more complex micro- and nanostructures .

The term "non-hardened material" or "non- hardened dispersion" refers to the liquid dispersion having a similar or essentially similar chemical and physical composition to that of the dispersion provided before the extrusion step (step b) ) . In particular, the viscosity of the non-hardened dispersion is similar or essentially similar to that of the dispersion provided before the extrusion step. In other words, the dispersion obtained after step b) differs from the dispersion provided before step b) in only its size and/or shape.

The term "exit die" used in co-extrusion processes is known in the field. It normally consists of a manifold combining different streams into one composite stream. In conventional extrusion (or when using relatively high viscosity dispersions) holes in the extruded material are produced by extrusion around mechanical elements (mandrels) present in the die and arranged parallel to the flow direction. The structure of the elements is then inversely replicated in the extrudate. In the present invention, in cases where the viscosity of the dispersion is particularly low, it is found advantageous when the mechanical elements described above consist of tubes delivering (hydrodynamic) structuring fluids. The location where the mechanical elements end in an extrusion die, or where the last dispersion or addi- tional liquid(s) (such as structuring liquid(s)) exit the mechanical element in co-extrusion dies, is defined as the location where structuring is complete ("end of exit die") ; although the size of the outer conduit may not change. Beyond this point the additional liquids and the dispersion maintain the shape of the cross section of the composite stream defined by the mechanical elements (i.e., exit die) and enable thereafter curing in either dynamic or pseudo-static sheathing fluids.

In more general terms, in a first aspect, the invention relates to an extrusion process for producing shaped composites, comprising the steps of a) providing a first dispersion, which comprises i) one or more inorganic particles, ii) one or more monomers, curable by electromagnetic radiation, and optionally one or more oligomers and/or polymers which are either non-curable or curable by electromagnetic radiation, iii) optionally one or more initiators, responsive to electromagnetic radiation, iv) optionally one or more surfactants, v) optionally one or more diluents; then b) processing said dispersion through a die; then c) subjecting the obtained material to a curing step initiated by electromagnetic radiation; then optionally d) subjecting the obtained material to a purification step, then optionally e) subjecting the obtained material to an assembly step, wherein step b) and / or step c) is optionally aided by a sheathing fluid. In one embodiment, the concentration of component (i) in said dispersion is above 1 vol.%, preferably above 5 vol.%. In a further embodiment, component (ii) comprises not more than 50 vol.% polymer, preferably not more than 20 vol.% polymer. It is apparent from the description provided herein, that the material which is subject to step c) is a non-hardened / non-cured dispersion which is hardened / cured during step c) . It was found that the use of non-hardened dispersion as a starting material in step c) allows the use of new compositions, new processes and results in new products having new compositions and microstructures . The invention therefore relates in advantageous embodiments to such processes,

• wherein step b) and optionally c) is aided by a sheathing fluid ("dynamic sheathing") , or • wherein step c) is aided by a sheathing fluid ("pseu- dostatic sheathing"; in this embodiment, the sheathing fluid is present in the form of a liquid sheathing bath) , or

• wherein neither step b) nor step c) are aided by a sheathing fluid ("no sheath") .

As outlined above, said sheathing fluid is non- coagulating with respect to the dispersion and not hardened during steps b) or c) .

The inventive process provides a composite containing inorganic particles and a cured polymer. The process according to the first aspect of the invention benefits from the use of a curing step to harden (solidify the liquid dispersion) the extruded material since this enables shaping by an extrusion step of very low viscosity dispersions and stabilize their shape rapidly by hardening to very high viscosity solid-like materials, (preferably crosslinked thermoset material) during the curing step. This aspect is termed here efficient decoup- ling of the viscosity during the flow / shaping (extrusion) and hardening (curing) steps. In other words, the mechanical shaping of a composition of relatively low viscosity liquid on the one hand side and the curing step to solidify the liquid on the other hand side are tempo- rally (and preferably also special) separated.

The inventive process further benefits from the ability to work at comparatively low process temperatures. Advantageously, process steps a), b) and c) are performed at a temperature wherein said dispersion does not exceed the melting temperature of the polymeric component present in component (ii) . Preferably, the process steps a), b) and c) are carried out at a tempera- ture between 0 - 80 ⁰C, preferably 10 - 40⁰C at or around room temperature. The inventive process thus differs from known thermoplastic extrusion process in that the polymer components - if present - are processed well below their melting point.

The inventive process is particularly suit^¬ able for the manufacture of composites selected from the group consisting of fibres, tubes, tapes and sections of such fibres, tubes and tapes. Further, such composites may be unstructured, structured or micro-structured as defined herein. Further, the inventive process is suit^¬ able to obtain a single, a multitude of or an assembly of shaped composites as defined herein.

The first aspect of the invention shall be explained in further detail below. Particularly, the relevance of the sheathing fluid, the components i) to v) and the process steps a) - e) shall be explained in further detail.

Sheathing fluid: As mentioned above, the inventive process is optionally aided by a sheathing fluid. Such sheathing may be either "dynamic" or "pseudo- static". Suitable sheathing fluids are transparent or essentially transparent with regards to the radiation used during curing; particularly, such fluids are UV transparent. This property of the sheathing fluid is advantageous for fast and complete curing of the dispersion. Further, suitable sheathing fluids are non- coagulating with respect to the dispersions as defined herein; i.e. sheathing fluids do not coagulate / precipitate the dispersion in order to consolidate the composites produced. This property of the sheathing fluid is considered a significant difference to the conventional fluids used in known spinning processes, such as wet spinning. Sheathing fluids suitable for the inventive process do not harden during any of the processing steps. Sheathing fluids may also contain additives such as salts and surfactants. In one embodiment, the sheathing fluid (either a pseudostatic or dynamic sheathing fluid) is water.

Thus, the present invention relates in one embodiment to a process as described herein, wherein step b) is aided by a dynamic sheathing fluid passing the die along with said dispersion. In this embodiment, the sheathing fluid passes the die along with said first dispersion. A dynamic sheathing fluid having a viscosity in the range of 1/10000 to 10, preferably 1/100 to 10 fold the viscosity of said dispersion was found to be suitable. The viscosities are defined at the particular conditions of shear rate and temperature during extrusion.

The present invention relates in a further embodiment to a process as described herein, wherein step c) is aided by a pseudo-static sheathing fluid. In this embodiment, the die may be arranged before or within a reservoir of such sheathing fluid. A pseudo-static sheathing fluid having a viscosity above 0.3 mPa*s was found to be suitable. 0.3 mPa*s is the viscosity of water (a fluid found suitable as pseudo-static sheathing fluid for the experiments done so far) at temperatures just below 100⁰C.

The present invention relates in a further embodiment to a process as described herein, wherein step b) is aided by a dynamic sheathing as described herein and step c) is aided by a pseudo-static sheathing fluid as described herein.

The present invention relates in a further embodiment to a process as described herein, wherein no sheathing fluid is used to aid the process. This process is advantageous for starting materials that have rheological properties between those used for conventional extrusion and those of the present invention which are advantageously produced using sheaths.

In the absence of pseudo-static sheathing fluid, the extruded material (with or without a dynamic sheath) may be extruded using known extrusion processes (e.g. directly to air) .

Component i) It was found particularly suit- able to use inorganic particles having an average diameter in the range of lnm to 10 micrometer, preferably in the range of 10 nanometres to 1 micrometer.

The choice of particles depends on specific application: for example inert, functional (opti- cal/magnetic/electric/ferroelectric) etc. particles can be used. Colloidal particles are preferred for the current application where wall thickness approaches 1-100 micrometers. The shape of the particle is not limiting. Suitable particles may have a round, an irregular, a nanofiber-type, a nanotube-type, core/shell type or an aggregated shape.

The particle material to be used may be selected from a wide range of materials. Basically, any inorganic particle may be used. This includes metals, alloys, metal oxides, metal hydroxides, metal hydrides, metal nitrides, metal carbides and metal salts, glasses as well as multicomponent particles. In the context of the present invention, preceramic polymers are not considered a member of the group of component i) . The term metal is used in its broadest sense, including main group metals, transition metals, rare earth metals and metalloids. By way of example, stainless steel, Al₂O₃, SiOo, Si₃N₄, SiC, hydroxyapathite, zirconia, PZT, ZnO, CeOr, TiO₂ are identified as materials for inorganic particles. Mixtures of particles may also be used. The limiting parameters of the extrusion process are primar- ily related to dispersion properties, rather than properties of the particle material.

The amount of inorganic particles, as defined herein, may vary in a broad range. Suitable amounts depend on the intended use of the shaped composite / shaped inorganic article. Typically, the concentration of such inorganic particles is above 5 vol-% of the dispersion.

Component ii) The type of compound selected from the group consisting of curable monomer, oligomer and/or polymer to be used is less critical. Basically, any curable material may be used, including mono- and higher functional monomers (crosslinkers) and oligomers. Commercially available (e. g. Ciba, Du Pont, DSM, Ashai Denka, BASF and others) stereolitography resins are suitable. Further, said monomers, oligomers and / or polymers may be selected from the group consisting of acrylic monomers such as acrylates and derivatives thereof, (such as methacrylates, cyanoacrylate, acryla- mide and acrylic esters) and co-polymers containing such acrylates. Acrylate, as used herein, includes monomers and derivatives thereof. Further, said monomers, oligomers and/or polymers may be selected from the group consisting of epoxides, vinyl and vinyl ether monomers.

Such curable monomers / polymers may be used pure, diluted in organic solvents or as water based systems. By way of example, mixtures of uv-vis curable mono- and multifunctional acrylates may be used. The resulting cured polymer properties are dependent on the starting monomers, ratio between multi and mono func^¬ tional monomers as well as on the choice of oligomers or polymers (e.g. urethane acrylates, epoxy acrylates) .

Monomers / oligomers / polymers having large content of oxygen (such as above 20 wt-%; preferably above 35 wt-%) are preferred for cases where the de- binding step (described later) is done without oxygen. It is believed that this measure prevents excessive carbonization during this step.

Further, monomers / oligomers / polymers having advantageous magnetic, electric, ferromagnetic, optical properties may be used.

According to the present invention, component ii) consists primarily of monomers in order to provide low viscosity dispersions. The polymer component is used primarily to modify the nature of resulting composite and as viscosity/rheology modifier. The polymer content in component (ii) is preferably not more than 50 vol.%, more preferably not more than 20 vol.%.

Component iii) The type of initiator to be used (if any) is less critical. Basically, the initiator must be compatible to component ii) and to the type of curing. Preferred are initiators responsive to electromagnetic radiation such as UV or visible radiation. By way of example, LTM, TPO or organic sulphur may be used, either as single initiator or as a mixture thereof. Totally organic initiators are preferred for shaped articles that are high purity metals, glass or ceramics. In a preferred embodiment the photoinitiators which are used act in a radical or cationic mechanism.

Component iv) The type of surfactant to be used (if any) is less critical. Basically, any surfactant compatible with component i) , ii) and iii) which provides adequate dispersion is suitable. Preferred are surfac- tants that provide high coverage of the particle. By way of example, anionic, cationic, non-ionic, zwitterionic surfactants or polyeletrolyte surfactants may be used. In a preferred embodiment anionic or cationic comb- polyelectrolyte surfactants are used.

Component v) The type of diluent to be used is less critical. Basically, any diluent compatible with the component ii) and iii) (if present) may be used. Diluents may be used to adjust viscosity and / or reac- tivty as well as the properties of the resulting shaped composite. Preferably, the diluent can also be a radia- tion active monomer of low viscosity as already used in component ii. Of these, mono acrylate monomers are preferred. Aqueous systems use water as diluent.

Further additives / components (e.g. anti- foamers) commonly used in dispersion formulation which are known to a person skilled in the art may be further present in the dispersions. These additives / components are typically added to the dispersion in quantities less than 1 vol . % (dispersion basis) .

Step a) Dispersions, suitable for the inventive process are known per se or are obtainable according to known procedures from known starting materials. Preferred components i) to iv) and properties are de- scribed herein. Suitable dispersions may be stored in a reservoir (tank) and fed to the shaping unit (i.e. a die) by use of conventional extrusion feeding devices, pumps or by means of gravity. Standard de-airing, filtering and mixing procedures can be employed to guaranty the quality of the dispersion and cured product. Nano-particulate and colloidal dispersions as defined herein are preferred. These are advantageous for small diameter articles (e.g. fibres) . It is also believed that radiation scattering during curing is minimized by the use of such disper- sions.

Viscosites for suitable dispersions may vary in a broad range. Preferred for liquid sheath processes, are dispersions showing a viscosity below 100 Pa«s, particular preferably below 10 Pa»s at shear rates and temperatures used for processing through the die (step b) . Preferred for processes using no sheaths or processes using gas sheaths are dispersions showing a viscosity below 1000 Pa»s, preferably below 500 Pa»s, particular preferably below 100 Pa* s at shear rates and temperatures used for processing through the die (step b) . Temperature and shear rates can be used as variables for viscosity modification. It is understood that a dispersion as disclosed herein excludes polymer melts. In case a polymer is present in a dispersion as defined herein, the temperature of the dispersion in step a) and b) does not exceed the melting temperature of such polymer present. In a preferred embodiment, the inventive process is carried out at a temperature range of 0 - 80 ⁰C, preferably 10 - 40 ⁰C or around room temperature.

Particle concentrations for suitable dispersions may vary in a broad range. Preferably, suitable dispersions for manufacturing shaped composites have concentrations below 70 vol.% of component i) . An important requirement for a functional polymer/particle composites, for example those requiring high electrical conductivity, is that the conductive particle concentra- tion exceeds a certain limit known as the percolation threshold. This is typically > 20 vol.%. Below the percolation threshold the composite is substantially non- conductive and above the percolation threshold substantially conductive. Other functions such as heat transfer, piezoelectricity, and magnetic susceptibility are also related to percolation phenomena. A similar, minimum volume fraction is critical to obtain self-supporting inorganic articles after de-binding. For articles requiring sintering to full density, particle concentration > 40 vol.% is advantageous.

In an advantageous embodiment, the invention relates to a manufacturing process as described herein wherein said first dispersion is complemented by one or more additional liquids, such process is referred to as "co-extrusion process". Said additional liquid (s) may be independently selected from the following groups: a) one or more second dispersion (s) ; b) one or more curable structuring liquid(s); c) one or more non curable structuring liquid(s) .

The concept of co-extrusion shall be ex- plained in further detail below, whereby any extrusion process as described herein consisting of additional liquid (s) (besides "first dispersion" and "sheathing fluid") is considered a co-extrusion.

In one embodiment, the first dispersion as defined herein may be complemented by one or more second dispersion (s) ("group a") . Such second dispersion will pass the die along with said first dispersion. Thus, two or more dispersions having different properties are fed to the die. This offers a method for manufacturing heterogeneous (e.g. "multilayered") shaped composites / shaped articles. Further, the particles of said first and said second dispersion differ from each other in at least one parameter. For example, said second dispersion may contain particles of different material and / or different particle size. The components i) to v) may be selected according to the definitions given herein. Further, as indicated above, the particles (component i) may also be selected from the group of organic particles. Consequently, such second dispersion, comprises i) one or more organic and/or inorganic particles, preferably inorganic particles; ii) one or more monomers, curable by electromagnetic radiation, and optionally one or more oligomers and/or polymers, which are either non-curable or curable by electromagnetic radiation; iii) optionally one or more initiators, responsive to electromagnetic radiation, iv) optionally one or more surfactants, v) optionally one or more diluents. Further, as component i) of said second dispersion also organic particles are suitable. By this embodiment, it is possible to obtain heterogeneous shaped composites / shaped inorganic articles . In an advantageous embodiment, said particles in second dispersion (s) are selected from the same group of inert or functional particles of component i.

In an advantageous embodiment, the concentra- tion of component (i) in said additional liquid of "group a" is above 5 vol.%. In an advantageous embodiment, component (ii) in said additional liquid of group a) comprises not more than 50% polymer, preferably not more than 20% polymer.

In a further embodiment, the first dispersion as defined herein may be complemented by one or more structuring fluids (particularly liquids) curable by electromagnetic radiation ("group b") . Such curable structuring liquids will pass the die along with said first dispersion. Materials suitable for such curable liquids basically correspond with those of said first dispersion, with the exception that particles are absent. Thus, suitable curable structuring liquids comprise i) one or more curable monomers, curable by electromagnetic radiation, and optionally one or more oligomers and/or polymers, which are either non-curable or curable by electromagnetic radiation;; ii) optionally one or more initiators, responsive to electromagnetic radiation; iii) optionally one or more surfactants; iv) optionally one or more diluents. The cured structuring liquid is part of the structure of a shaped composite but is replicated in the inorganic article as holes after the de-binding step. By this embodiment, it is possible to obtain heterogene- ous and homogeneous shaped composites / structured shaped inorganic articles.

In an advantageous embodiment, component (ii) in said additional liquids of groups b) comprises not more than 50% polymer, preferably not more than 20% polymer.

In an advantageous embodiment, the invention relates to a process as described herein, wherein the liquid of groups a) and b) contains or essentially consists of monomers, oligomers and/or polymers of acrylates or meth-acrylates .

In a further embodiment, the first dispersion as defined herein may be complemented by one or more non- curable structuring fluids (particularly liquids; "group c") . Such non-curable structuring liquids will pass the die along with said first dispersion. Materials suitable for such curable liquids basically correspond with those of said sheathing liquid. Thus, suitable non-curable structuring liquids comprise i) one or more diluents and ii) optionally one or more non-curable oligomers and/or polymers. By this embodiment, it is possible to obtain heterogeneous and homogeneous structured shaped composites / structured shaped inorganic articles.

In an advantageous embodiment, the invention relates to a process as described herein, wherein the liquid of group c) has a viscosity in the range of 1/10000 to 10, preferably 1/500 to 10 fold the viscosity of said first dispersion.

In an advantageous embodiment, component (ii) in said additional liquids of groups c) comprises not more than 50% polymer, preferably not more than 20% polymer.

In this embodiment, in the absence of dynamic sheathing fluid first dispersion and non curable liquid of group c) define at least 20%, preferably 50% of the outer surface and the curable structuring liquid of group b) defines only inner surfaces.

Advantageously, the additional fluids (liquids) as defined in group a) , b) and c) above and said first dispersion are mutually non-coagulating with respect to each other.

Further, the processing temperature of said additional liquid is within the limits given above. In an advantageous embodiment, all liquids passing the die are adjusted to a laminar flow regime. This measure avoids flow instabilities and excessive mixing.

Step b) is predominantly determined by the viscosity of dispersion (s) and structuring liquids and not the particle material. This step may also be termed the "shaping step". Conventional extrusion / co-extrusion utilizes the dependence of viscosity on temperature and/or shear rate (e.g., dispersions in polymer melts) to obtain a sufficiently low viscosity for shaping and suffciently high viscosity for the extruded body to prevent unwanted deformation after exiting the die. The range for a specific starting material depends on the temperatures and pressures used, but cannot be set independently. One of the advantages of the present invention lies in the efficient decoupling of (micro-) forming and setting viscosities. The composites are microstructured at low viscosities but can be cured in several seconds to rigid bodies. Extrusion of dispersions with much lower viscosities than in conventional extrusion becomes possible. This establishes a lower limit for fiber diameter or wall thickness obtainable at given extrusion conditions. In addition, the relatively low viscosity aids co-extrusion since the different liquid streams (dispersions and structuring liquids) can be combined at dimensions similar to or close to the final cured dimensions. In summary, the de-coupling of (micro-) forming and setting viscosities is considered a major advantage. Thus, step b) referred to above is advantageously an extrusion or co-extrusion step.

Step c) The curing of the initially formed composite may be performed according to standard processes, e.g. known from "rapid prototyping processes". This step is predominantly determined on the material's refractive index and radiation used (e.g., UV) absorption and on particle size. This only limits the thickness of a shaped composite available according to the inventive process, but the process is expected to work for all materials below such thickness. Appropriate curing conditions depend on the combination of monomers, oli- gomers/polymers and initiators used in the preceding step as well as size of the inorganic particle, concentration and material used (e.g., index of refraction, radiation absorption) .

As outlined above, there is no hardening step prior to step c) ; step c) is the hardening step. In addition, the dispersion as defined herein does not come into contact with any solid material between steps b) and c) .

In an advantageous embodiment, the curing step consists of a radiation step using radiation in the ultraviolet and / or visible spectrum.

In an advantageous embodiment, the curing step is performed by focused beams or laser beams; or by a flood exposure unit equipped with a mask and a shutter. This equipment enables to selectively cure sections of the composite and offers an additional method for manufacturing structured shaped composites / articles. The selective curing can be applied to sections of the cross section and/or sectioning in the direction of flow. The later produces discrete elements rather than fibres or tapes. Using a focused beam or a radiation source/mask to selectively pattern radiation curable materials is a well established technology used for structuring / etching surfaces of articles; suitable processes and equipment are known from stereolithography or micro- stereolithography. Here however, the selective curing of dispersions is done under flow conditions. This embodi- ment is particularly suitable in combination with the dynamic sheathing fluid as described herein. In a preferred embodiment, the curing time, is in the order of 1 - 20 seconds, preferably below 20 seconds. Suitable curing times are by way of example below 5 seconds for liquid sheath processes; below 10 seconds, preferably below 1 second for processes without sheath; below 1 second, preferably below 0.1 second for processes for gas sheath processes. Under these conditions the solubility of the dispersion in the sheath material is less important. In the context of the present invention the curing time may be defined as the time spent by the liquid dispersion from leaving the die until it cures to a rigid body sufficient for shape stabilization.

In an advantageous embodiment, the invention relates to a process as described herein, wherein before and / or during step c) said fibre, tape, tube and sections thereof are shaped into i) a random network structure or ii) a predetermined three dimensional structure on a substrate. In this embodiment, said fibre, tape, tube (or sections thereof) are either deposited in a predetermined spatial position (known from the field of rapid prototyping, see above) or randomly oriented (known from nono-wovens, see above) and are connected to each others. This embodiment is advantageous with processes using gas sheaths or no sheaths. When deposition to produce a predetermined structure is employed, this embodiment may also be considered a direct write process or a robocasting deposition process. Thus, the invention also relates to direct write and robocasting deposition processes comprising the steps as defined herein. The article obtained by such process typically retains the structure of the fibre, tube, tape or section thereof initially obtained in process step b) .

Step d) Depending on the intended use of the shaped composite initially obtained and of the starting materials used, one or more further purification steps may follow the curing step. Such steps may be employed to remove unwanted starting materials, sheathing fluids, diluents or other reaction aids, or to further modify the surface of the shaped composite. Advantageously, the purification comprises one or more washing and drying steps using a solvent or mixture of solvents. For example acetone, alcohols or water for an organic based acrylate system; water or alcohol for an aqueous system. Systems containing diluents may require drying steps even if washing is not required. ^

Step e) Depending on the intended use of the shaped composite obtained and of the starting materials used, one or more further assembly (finishing) steps may follow the previously described steps. These steps include but not limited to coating, cutting, weaving, assembling into other devices, pressing or shaping, all of which are known per se.

In a further embodiment, the assembly step may comprise the steps of coating, curing, purifying, heating of the material obtained. This embodiment allows to coat a material obtained with a further curable dispersion containing inorganic particles. This is particularly advantageous for obtaining thicker multiple layers.

In a second aspect, the invention relates to a process for manufacturing shaped inorganic articles, comprising the steps of manufacturing a shaped composite as described herein followed by f) a de-binding step and g) optionally followed by a sintering step, h) optionally followed by one or more finishing steps. This process provides a shaped article containing inorganic particles without (or essentially without) polymeric material. The process according to the second aspect of the invention benefits from the special shaping technique, and provides a very versatile process for manufacturing of a wide variety of inorganic articles having complex microstruc- tures at small dimensions. Typically, the shaped inorganic articles are obtained in the form of unstructured, structured or micro-structured fibre, tube, tape and/or sections thereof, preferably as micro-structured and unstructured fibres and tapes.

The second aspect of the invention shall be explained in further detail below.

Particle concentrations for suitable dispersions may vary in a broad range. Preferably, suitable dispersions for manufacturing shaped articles show a concentration above 20 vol.% of component i) , preferably between 40 - 70 vol.%. Preferably, suitable dispersions for manufacturing shaped functional composites show a concentration above 20 vol.% of component i) , preferably above percolation threshold.

Step f) The de-binding step according to this invention is designed to remove all (or essentially all) organic material from the shaped composite obtained in the previous step. The product of this de-binding step is named shaped inorganic article. Such de-binding steps are known per se.

Preferably, the de-binding comprises heating the composite material. Temperatures, heating times and atmospheres required depend on the structure of the shaped composite, the type and amount of organic material present in said composite. Atmosphere, heating rate and temperatures are preferably adjusted to avoid undesired sintering and/or destruction of the shape and/or undesirable reaction of the particles. Suitable parameters may be identified by routine experiments. Typically, heating temperatures are in the range of 200-800 ⁰C, preferred in the range of 400 - 700 ⁰C, Oxygen containing atmosphere is preferred for materials where oxidation is not critical or for products of the de-binding step which belong to the group of metal

(or mixed metal) oxides or hydroxides. Air atmosphere is generally preferred.

Inert or reducing atmosphere is preferred if products are such as metals, carbides, nitrides which may oxidize during the de-binding treatment.

It is also possible to change atmospheres during de-binding.

Step g) The sintering step according to this invention is designed to achieve a partial or full density based on the theoretical density of one or more bulk materials in the shaped article. Such sintering steps are known per se. Temperatures and heating times required depend on the structure of the shaped composite, the particle material, porosity. Temperatures should be selected to achieve sintering and to avoid / reduce destruction of the shape. Sintering routines (temperature, time, atmospheres) are highly material dependent but are known to the person skilled in the art. It also depends whether partial or full sintering is desired. Partial sintering is designed to strengthen the porous body while retaining a significant fraction of porosity and surface area. This is advantageous for applications such as separation and catalysis. Full sintering eliminates substantially all porosity. Typical applications are for glasses, ceramics, metals.

Step h) Any finishing step known in the field may be applied to the shaped article obtained by the inventive process. This includes, by way of example, cutting, coating, assembling into other devices, pressing or shaping.

In a further embodiment, the finishing step may also comprise the steps coating, curing, purifying, and heating of the material obtained. This embodiment allows coating a material obtained with a further curable dispersion containing inorganic particles. This is particularly advantageous for obtaining thicker multiple layers.

It is further understood that the mandatory steps - a) , b) and c) for the manufacture of composites, a) , b) , c) and f) for the manufacture of articles - may be combined with any of the optional steps d) , e) g) and h) .

In a third aspect, the invention relates to a manufacturing device adapted to the processes as de- scribed herein. The description of the manufacturing devices is complemented by the figures 3 - 6. A manufacturing device for shaped composites as defined herein comprises at least an extrusion unit and a curing unit; a manufacturing device for shaped articles comprises at least an extrusion unit, a curing unit and a de-binding unit. The further units are optional, thus shown in brackets in the figures. Depending on the presence or absence of de-binding and sintering unit, the manufacturing device is adapted to produce shaped composites (no de-binding / sintering unit) or to produce shaped articles .

Devices for dynamic and pseudostatic sheathing are explained below, followed by a description of the figures .

In one embodiment, the invention therefore relates to a manufacturing device as described above, wherein extrusion unit and curing unit are arranged in one housing. This embodiment may apply to both dynamic and pseudostatic sheathing as explained below. Dynamic Sheathing: In one embodiment, the invention therefore relates to a manufacturing device for manufacturing a shaped composite, particularly an extruder, comprising a) an extrusion unit comprising an exit die, and b) a curing unit comprising a electromagnetic radiation source, wherein said exit die is in fluid communication with a reservoir of a first dispersion, with a reservoir of a sheathing fluid, optionally with one or more reservoirs of additional fluids, and wherein said exit die defines a cross section for said shaped composite encompassing an outer surface and an inner surface, and wherein said exit die is arranged to provide at the outer surface said sheathing fluid and at the inner surface said first dispersion and said optional additional liquid(s), and wherein the curing unit is located directly behind said exit die. It is understood that materials used in such a device comply with the require- ments as described herein, particularly, sheathing liquid, first dispersion and additional liquids are mutually non-coagulating. The sheathing fluids do not harden during any of the processing steps.

In a further variation of this embodiment, the invention therefore relates to a manufacturing device as described above, wherein the curing unit comprises either a unit comprising a focused beam / laser or a flood exposure unit optionally equipped with a mask and / or a shutter.

In a preferred embodiment, the invention therefore relates to a manufacturing device as described above, wherein extrusion unit and curing unit are arranged in one housing. Pseudostat±c Sheathing: In one embodiment, the invention therefore relates to a manufacturing device for manufacturing a shaped composite, particularly an extruder, comprising c) an extrusion unit comprising an exit die, d) a curing unit comprising an electromagnetic radiation source, and e) a reservoir of a sheathing liquid wherein said exit die is in liquid communication with a reservoir of a first dispersion, optionally with one or more reservoirs of additional liquids, and wherein said exit die defines a cross section for said shaped composite encompassing an outer surface and an inner surface, and wherein said reservoir of a sheathing liquid is arranged to provide said sheathing liquid in a pseudo-static fashion to said exit die. In this embodiment, said reservoir of sheathing liquid is arranged behind said exit die. It is understood that materials used in such a device comply with the requirements as described herein, particularly, sheating liquid, first dispersion and additional liquids are mutually non- coagulating. The sheathing fluids do not harden during any of the processing steps.

In a preferred embodiment, the invention relates to a manufacturing device as described above, wherein said curing unit and said reservoir of a sheathing fluid are arranged in one housing.

Further, the invention relates to a manufacturing device as described herein comprising a) an extrusion unit comprising an exit die; followed by b) a curing unit comprising an electromagnetic radia- tion source; optionally followed by c) a purification unit, optionally followed by d) an assembly unit; optionally followed by e) a debinding unit, optionally followed by f) a sintering unit, optionally followed by g) a finishing unit. whereby at least one of the units c) to g) is present in addition to a) and b) .

It is further understood that the units may be run in parallel, e.g. two extrusion units followed by one or more curing unit. Further, certain elements of a unit may be present as either a single element or in manifold (i.e. one or more radiation device (s) in the curing or one or more dies in the extrusion unit) .

The units of the device are followed by each other as defined below. This means that the material prepared in one unit is transported to the next unit as defined herein. In one embodiment, the units are in fluid communication, meaning that manufactured material is directly transported to the following unit.

The manufacturing device may be adapted to continuous or batch wise production; as known to persons in the field. In an advantageous embodiment, extrusion and curing unit are adapted to a continuous process. This embodiment provides low investment costs and high flexibility of the process. In a further advantageous embodiment, all units are adapted to a continuous process. This embodiment provides low manufacturing costs in large scale production.

In a first embodiment (c.f. Fig. 3), the invention relates to a manufacturing device comprising an extrusion unit comprising an exit die, followed by a curing unit comprising a radiation source, optionally followed by a purification unit, wherein said exit die is in fluid communication with a reservoir of a first dispersion, with a reservoir of a sheathing fluid, wherein said exit die defines a cross section for a composite material and wherein said exit die is arranged to provide said sheathing fluid at the outer surface and said first dispersion at the inner surface of said cross section. The sheath may be dynamic (i.e., flows and encompasses the dispersion in the structuring die and curing unit, Fig. 3a) or pseudo-static (i.e., when the dispersion exits the die into a reservoir and encompassed by a pseudo-static sheath during the curing step, Fig. 3b) . Such manufacturing devices may be used to produce homogeneous, non-structured composites / articles. As explained above, exit die and said reservoirs are arranged to form an extruder. As discussed above, extrusion processes for the manufacture of the shaped composite / article are much preferred.

In a further embodiment (c.f. Fig. 4), the invention relates to a manufacturing device as described herein wherein said exit die is in fluid communication with a reservoir of a first dispersion, additional reservoir of a second dispersion and additional reservoir of structuring fluid wherein the reservoir of the pseudo- static sheathing fluid is arranged behind said exit die and is arranged with the curing unit in one housing. Such manufacturing device may be used to produce heterogeneous (e.g., layered) and structured composites/ articles. It is further understood that such process is possible with additional dispersions and/or structuring liguids; and with the use of dynamic sheathing fluids instead or along with a pseudo-static liquid.

In a further embodiment (c.f. Fig. 5), the invention relates to a manufacturing device as described herein wherein said radiation device is partly shielded by a mask/shutter (M/S, Fig. 5a) . Alternatively, a focused laser beam (LS, Fig. 5b) is used. In both cases materials can be selectively cured and therefore struc- tured in selected areas. In addition, the laser or mask can be made to move relative to the extruded material during the curing step producing time varying structuring or cured sections. In both cases materials can be selec- tively cured in selected areas. Such manufacturing device may be used to produce lithographically structured, composites / articles. Suitable extrusion units are either that disclosed in Fig. 3 (providing homogeneous composites) or in Fig. 4 (providing structured, heteroge- neous composites / articles) .

To further explain this aspect of the invention, the individual units and specific elements thereof are explained in more detail below. Although not arranged in the present way, the units themselves are known or may be readily adapted. It should be further noted that ancillary units, e.g. for de-airing, mixing, filtering, pumping / transporting, collection, storage, measuring, controlling are not explicitly shown. Such units are known to the person skilled in the art.

Extrusion unit: Extruders are known in the field. Due to the comparatively low viscosity of the material to be extruded, materials and pumps may be chosen from a wide variety of available components. Key element of the extruder is the exit die. The exit die and the structuring liquids employed define the cross-section of the material produced (the non-cured composite) . The exit die is optionally further adapted to provide a dynamic sheathing fluid at the outer surface and the first dispersion (and optionally other dispersions and structuring liquids) at the inner surface of said cross section. The structured stream (with or without a dynamic sheath) may be extruded using known extrusion processes (e.g. directly to air) . Alternatively, the structured stream (with or without a dynamic sheath) is extruded into a reservoir of pseudo-static sheathing liquid. These arrangements become clearer when referring to figures 2d, 3, 4 and 5. The maximum size of the exit die is primarily determined by the curing depth of materials to be extruded. Exit dies larger than the curing thickness can be employed if a) the process is adapted to provide new layers to existing structured or unstructured fibres or tapes and b) use of heat curable dispersion at the inner layer surrounded by UV curable dispersion with thickness below the curing depth. The heat curable dispersions are cured in a separate curing unit.

It is further apparent that the exit die is in fluid communication with a reservoir of a first (and optionally second or more) dispersions, structuring liquids, and optionally with reservoirs of a dynamic and/or pseudo-static sheathing fluid.

The die outer and/or inner surfaces may be coated with mould release agents to reduce sticking of the dispersion and reduce friction.

Curing unit: According to the present invention, curing is radiation initiated. Thus, at least one source of radiation, such as a lamp emitting UV and/or visible light, is present in this unit. The unit is adapted to ensure the extrudate (which is provided by or just after the exit die) is exposed to the radiation, to ensure appropriate curing (i.e. fully or partially) .

In cases where no lithographical structuring is needed the curing unit consists of UV lamps providing flood exposure (rather than focused beams or laser beams) . These lamps are conveniently positioned outside a radiation transparent reservoir of the pseudostatic sheathing liquid, around a radiation transparent die (when dynamic sheath is used) or around the dispersion stream leaving the extrusion die (when extrusion is done directly to air) . If only a pseaudostatic sheathing liquid is used, the reservoir material and the sheathing fluids are substantially transparent to the radiation. The shaped/structured material exiting the extrusion die is surrounded by the sheathing fluid. Advantageously, e.g. to prevent blockage of the die by premature curing of the material stream, the exit die and its extension, which is in fluid communication with the sheathing fluid, is made of radiation opaque materials and/or the radiation curing zone begins a distance of 0.1-10 cm from the exit of the die.

If a dynamic sheath is used with or without a pseudostatic sheath, curing is advantageously done shortly after the mechanical structuring is complete in the exit die. The outer conduit material in the radiation zone and the sheathing fluid is substantially transparent to radiation. In one embodiment, where lithographical structuring is required, the curing unit is also equipped with one or more masks and optionally with one or more shutters. This arrangement enables the manufacture of shaped structured articles / composites. Alternatively, similar structuring can be achieved with one or more focused beams (e.g. laser beams) which are static or move with respect to the outer conduit where curing is performed.

Purification unit: Preferred purification is a washing or rinsing step; suitable units are thus equipped with a washing bath and/or a sprayer and/or dryer.

Assembly unit: By this term, one or more units are defined that further process the material obtained. Such steps may be coating, cutting, weaving, assembling into other devices, pressing or shaping. Such further process steps are known in the field and may be adapted to the present material. De-binding unit: The de-binding unit aims to remove organic components from the material, preferably by decomposition of the organic constituent; suitable units are thus equipped with a heating element to produce the required temperatures. Heating may take place in the presence or absence of oxygen; i.e. under oxidizing, reducing or inert conditions.

Sintering unit: The sintering unit aims to effect a partial or full densification of at least one of the inorganic particles of the shaped article; suitable units are thus equipped with a heating element or other radiation (e.g. microwave) to produce the required temperatures. Sintering may take place in the presence or absence of oxygen; i.e. under oxidizing, reducing or inert conditions.

Finishing unit: By this term, one or more units are defined that further process the material obtained. Such steps may be cutting, coating, assembling into other devices, pressing or shaping. Such further process steps are known in the field and may be adapted to the present material.

In a fourth aspect, the invention relates to new shaped composites /articles, in the form of an unstructured, structured or micro-structured fibre, tube, tape and sections thereof. In an advantageous embodiment, the invention relates to a process as described herein, wherein said fibre, tape or tube and sections thereof are deposited and/or assembled into three dimensional structure .

Thus, in one embodiment, the invention re- lates to new shaped composites, in the form of an^' unstructured, structured or micro-structured fibre, tube, tape and sections thereof, obtainable or obtained by a method as described herein. These new materials benefit from the wide choice of monomers, oligomers/polymers, photoinitiators and special hardening process used in the inventive process. For example, the elasticity, degree of crosslinking and other polymer properties can be tailored by a proper choice of the above mentioned variables as well as the type and size of the inorganic particles used, leading to new or improved inorganic/polymer

(nano) composite . The low temperature employed during the fabrication process is advantageous for biological and chemical applications.

In a further embodiment, the invention relates to new shaped inorganic articles, n the form of an unstructured, structured or micro-structured fibre, tube, tape and sections thereof. Further, the invention relates to shaped inorganic articles obtainable or obtained by a method as described herein. These new materials benefit from the ability to fabricate thin fibres, tubes and tapes from a variety of materials which are inaccessible by other techniques.

Further, the invention relates to the use of the shaped composites / articles, n the form of unstruc- tured, structured or micro-structured fibre, tube, tape and sections thereof, obtained or obtainable by a process as described herein. The uses are those that benefit from the special and potential advantages of the present invention such as flexibility in structuring and sectioning, mass production of relatively small diameter fibres and thin wall objects, flexibility in material combinations, small particle size of feedstock.

In a fifth aspect, the invention relates to new uses of the processes and devices as described herein. Thus, in one embodiment, the invention re^¬ lates to the use of a process as described herein for manufacturing shaped articles or composites preferably in the form of homogeneous / heterogeneous structured / unstructured fibre, tube or tape.

The inventive processes are particular useful for manufacturing small diameter simple or micro- structured fibres having also large open cross sectional area and/or thin wall (e.g., thin wall tubes) . These are easier to produce by the inventive process compared to conventional extrusion due to use of feedstock of lower viscosity. Further, the quality of heterogeneous composites benefit from improved quality of interface between layers resulting from the use of lower viscosity dispersions. The relatively low viscosity enables also combining of the co-extruded streams at dimensions similar to or close to the final cured dimensions.

In conventional extrusion, the die is constructed to yield desired cross section. Due to the lower viscosity in present process, it is found to be advantageous to obtain shaped articles / composites (e.g. tubes) when employing structuring liquids (in addition to structured die) .

Due to lithographical possibilities, such as with focused beams (e.g. laser beams) or a mask/shutter, selective time varying and/or curing of selected areas of the cross section of the extruded stream are possible. This enables for example a) partial curing of composite cross section close to the surface, b) forming thin sections in the flow direction having full or partial cured cross section, c) forming a continuous homogene- ous/heterogeneous fibre or tape by only lithographical means. These processes are advantageous with the dynamic sheath process and form part of the present invention. To further illustrate the invention, the following examples are provided. These examples are provided with no intent to limit the scope of the invention.

Example 1 - silica and silica/polymer fibres with psβudostatic sheath process: A UV curable dispersion containing 30 vol . % silica powder (Aerosil ox50, Evonic Degussa, Germany) and 70 vol.% monomer mixture was provided. The silica has an average particle size of 40 nanometer. The monomer mixture composition was 93.3% 4- HBA (4-Hydroxybutyl acrylate, BASF, Germany), 6.7% PEG 200 DA (Polyethyleneglycol 200 diacrylate, Rahn, Switzerland) . This composition results after curing in a cross linked polymer phase. 3% (monomer mixture basis) photoinitiator Genocure LTM (Rahn, Switzerland) was added to the dispersion and mixed throughly. The dispersion has a viscosity of 0.8 Pa-s (23°C, 100s^"1) . The dispersion was injected with the aid of a precision syringe pump (PHD 2000, Harvard Scientific, USA) in a continuous fashion with an 8 mm diameter syringe equipped with a die into a glass beaker with a diameter of 10 cm filled with DI water to a level of 15 cm. 9.5 mm long dies with diameters of 110 and 500 micrometers were used in two differ- ent experiments. The die was positioned 1-3 cm inside the DI water and was shielded from UV radiation by an aluminium tape. The average linear velocity of the dispersion stream passing the die was varied between 1-20 cm/s. A UV lamp producing 120 mW/cm² (Fe bulb, 10OW, Dr. Hδnle AG, Germany) positioned at one side of the beaker illuminated the bottom 10 cm of the beaker and cured the dispersion stream exiting the die before it reached the bottom of the beaker. Continuous fibres were separated from the water, washed with water and dried. All materials (e.g., dispersions, solvents) and all manipulations (e.g., curing and washing) were carried out at room temperature (25⁰C) . The resulting fibres have circular cross section and average diameters between of 120-600 micrometer, corresponding closely to the die diameter used during extrusion. The 120-130 micrometer fibres were debinded in air at 500⁰C for 2 hours and sintered at 1250⁰C for 1 hour. The resulting glass fibres are cylindrical and dense and have a diameter of 90-100 micrometer.

Example 2 - alumina and alumina/polymer fi- bres with pseudostatic sheath process, oval die: A UV curable dispersion containing 41.5 vol.% alumina particles (Taimicron TM-DAR, Taimei chemicals co., Ltd, Japan) and 58.5 vol.% monomer mixture was provided. The alumina powder has an average particle size of 150 nanometers and was pre-stabilized with 4.5 wt% Melpers4343 surfactant

(particle basis) obtained from BASF, Germany. The monomer mixture composition was 93.3% 4-HBA, and 6.7% PEG 200 DA.

3% (monomer mixture basis) Genocure LTM photoinitiator was added to the dispersion and mixed thoroughly. The dispersion has a viscosity of 0.25 Pa-s (23°C, 500s^""1) . A similar extrusion and UV curing setup described in example 1 was used with a 160 micrometer die. The average linear velocity of the dispersion stream passing the die was varied between 1-20 cm/s. The dispersion stream exiting the die cured before it reached the bottom of the beaker. Continuous fibres were separated from the water, washed with water and dried. The resulting fibres have circular cross section and average diameters between of 130-180 micrometer, corresponding closely to the die diameter used during extrusion. In an additional experiment, the 160 die tip was pressed to form an elliptical shape. The cross section of the resulting fibres changed accordingly. All materials (e.g., dispersions, solvents) and all manipulations (e.g., curing and washing) are carried out at 25⁰C.

In an additional experiment using identical extrusion and curing setup with a dispersion containing 35 vol.% particles, the cured fibres extruded at 10 cm/s were collected on a tensioning/elongation device. The tensioning device consisted of a 2 cm diameter rotating cylinder held horizontally above the bottom of the beaker. The rotating speed was 600 rpm. A glass cylinder protected the die from vibration caused by the tensioning device. Due to the tension created by a collection velocity significantly higher than the extrusion velocity, the dispersion stream is thinned at the die exit. The resulting fibres have circular cross section and average diameter of 50 micrometers. It is apparent, that the elongation / tensioning can be generated by other devices or by means of gravity, electrohydrdynamically etc. Sections of tensioned/elongated and non tensioned fibres were debinded in air at 650⁰C, sintered at 1500⁰C for 1 hour and cooled to room temperature in 15 hours. The resulting continuous fibres are dense, circular and have diameters between 100-130 micrometers (non tensioned) and average diameter of 40 micrometers (ten- sioned) .

In an additional experiment a similar extrusion and curing setup was used with dispersion containing 41.5 vol.% particles. The die consisted of a brass disk having a 250 micrometer long, 50 micrometer diameter exit hole. The average linear velocity of the dispersion stream passing the die was varied between 1-10 cm/s. The dispersion stream exiting the die cured before it reached the bottom of the beaker. Fibres with continuous length of several meters having circular cross sections and diameter of ~45 micrometers were produced.

Examples 1 and 2 demonstrate that ceramic/polymer composite fibres and ceramic fibres are available starting from colloidal dispersions in UV curable compositions containing only monomers. Moreover, the operations are done at room temperature. This shows that dispersions containing oligomers or polymers, polymer melts or polymer solutions are not essential for the hardening mechanism of the fibres. Moreover, it is known that the monomer 4-HBA, which comprises >90% of the monomer mixture is highly soluble in the water pseau- dostatic sheathing bath, demonstrating that fast curing employed here by UV radiation is critical for shape retention of the fibres. In addition, the drying step inherent in dry or wet spinning processes is avoided, resulting also in new inorganic/polymer nano-composite fibres .

Example 3 - silica/polymer composite tribes by co-extrusion with structuring liquids: The dispersion of example 1 was injected manually into a tube having a 3 mm ID. A 12.5% PVA aqueous solution (Optapix PA 4G, Zschim- mer&Schwarz Corp., Germany) having a viscosity of 0.05 Pa* s (23°C) was injected manually into the center of the silica dispersion stream providing a non-curable struc- turing liquid through a concentrically positioned PTFE tube of 1.6 mm OD and 0.8 mm ID. In general, the viscosity of the optapix solution can be provided in a wide range as it varies exponentially with optapix concentration. All UV transparent surfaces in the flow system which contain the dispersion (i.e., syringe, tip) are shielded from UV radiation with aluminium foil to prevent curing of the dispersion before exiting the die. The combined dispersion/ structuring liquid stream (flow ratio approximately 5:1) was injected at a linear speed of 1-2 cm/s into a UV curing setup similar to that of example 1. The tubes were cured before arriving at the bottom of the beaker. The resulting average dimensions of the silica/polymer composite tubes are 1.1 mm OD and 0.5 mm ID. All materials (e.g., dispersions, solvents) and all manipulations (e.g., curing and washing) were carried out at room temperature. Example 4 - silica/alumina core shell composite fibres by coextrusion process: A 35 vol.% alumina dispersion with monomer mixture composition similar to that of example 2 replaced the structuring liquid in example 4. Other details remained the same. The resulting core/shell fibres have an average diameter of 1.1 mm "and composite alumina core of 0.5 mm. The interface between the composite alumina core and composite silica shell appears intact.

Example 5 - alumina/polymer composite fibre obtained with dynamic sheath process: The alumina dispersion of example 2 was injected with a syringe pump (PHD 2000, Harvard Scientific, USA) equipped with 1 ml syringe at a rate of 0.05 ml/min through a 340 micrometer steel needle into the center of a 20% PVA aqueous solution dynamic sheath flowing in a 2 mm ID polyethylene tube. The sheath having a viscosity of 0.3 Pa • s (23°C) (viscosity ratio of ~1) was manually injected using a 50 ml syringe at a rate of approximately 1 ml/min. A 10 cm section of the tube (several cm away from the injection zone) was exposed to UV radiation using similar UV lamp described in the preceding examples. Continuous fibre with average diameter of 300 micrometer was produced at a rate of 1-2 cm/sec.

Example 6 - ZnO and ZnO/polymer composite fibre: A UV curable dispersion containing 37 vol.% ZnO powder (Sigma aldrich, Switzerland) and 63 vol.% resin was provided. The ZnO nanopowder has a particle size <100 nanometer and was pre-stabilized with 10 wt% Melpers4343 surfactant (particle basis) obtained from BASF, Germany. The monomer mixture composition was 93.3% 2-HEA (2- Hydroxyethyl Acrylate, BASF, Germany) and 6.7% PEG 200 DA. 3% (monomer mixture basis) Genocure LTM was added to the dispersion and mixed thoroughly. The details of fibre preparation are similar to those in example 1 only that the extrusion is done manually using 1 ml glass syringe equipped with a 160 micrometer die. Fibres of continuous length of several meters were separated from the water, washed and dried. The resulting ZnO/polymer fibre has an average diameter of ~170 micrometers. In addition, curing of >250 micrometer films with similar dispersions was demonstrated indicating that UV absorbing composites and articles are available using the inventive process.

The fibers were debinded and sintered as de- scribed in example 1. The resulting fibres have average diameter of 120 micrometers

Example 7 - polymer microstructure fibres by co-extrusion with structuring liquids: PEG 200 DA (viscosity of 0.025 Pa-s at 23⁰C) containing 1.4% Genocure TPO photoinitiator (Rahn, Switzerland) was injected manually into a tube having 4 mm ID. A 12.5% PVA aqueous solution having a viscosity of 0.05 Pa*s (viscosity ratio of 2) was injected manually into the monomer stream through two blunt steel needles, each of 0.6 mm ID and 0.8 mm OD. The needles were positioned about 1.25 mm from the wall and 1.5 mm from each other. The combined dispersion/structuring liquid stream (flow ratio approximately 1:1) was injected at a linear speed of 1-2 cm/s into a UV curing setup similar to that of examples 1-2. The microstructured fibres were cured before arriving at the bottom of the beaker. The fibres were washed with water and iso-propanol to remove the structuring liquid material from the holes. The fibres have circular cross section. The resulting dimensions of the fibre OD ranged between 0.8-1.3 mm and the diameter of the hole between 0.4-0.6 mm. Open area was about 40%. Wall thickness as small as 20 micrometer could be achieved. While this example does not include inorganic particles it shows that complex (micro-) structures are available using the inventive process. It is also possi- ble to significantly reduce dimensions by using appropriate equipment and adjusting viscosities of starting materials .

Example 8 - alumina fibres produced without sheath (s)

A viscous paste of 30 vol.% alumina (TM-DAR, no surfactant added) in PEG 200 DA was provided. 5% LTM photoinitiator (monomer basis) was added to the paste. The paste was vertically injected into air using a 1 ml syringe through a 340 micrometer steel needle, at a velocity of 1-2 cm/sec. The UV curing lamp of example 1 positioned below and side of the tip, cured the stream in 1-5 seconds and produced ~10 cm long fibres with diame- ters in the 300-450 micrometer range. The relatively short length of fibre is attributed to the tendency of the unsupported fibres to break due to gravity and perturbations .

This example demonstrates that long fibres can be produced given a conveyor pickup mechanism and/or automated injection.

In an additional experiment, the uncured soft fibres, which in this example due to the paste rheology are self supporting (i.e. do not deform under their own weight within the time scale typically needed for curing) , were deposited horizontally on a Teflon tray or aluminium foil. The structures were cured shortly after deposition by UV exposure using the curing lamp of example 1. The single fibres produced had diameters in the 300-450 micrometer range. Structures having multiple fibre layers were also prepared and had good interface properties .

This example demonstrates that fibres pro- duced without sheath and 3d structures are available using the inventive process. Example 9 - hydroxyapatitβ/polymβr composite fibre: A UV curable dispersion/paste containing 33 vol.% Hydroxyapatite (HA) powder (Sigma aldrich, Switzerland) and 67 vol.% resin was provided. The HA nanopowder has an average particle size <200 nanometer. The resin composition was 93.3% 4-HBA and 6.7% PEG 200 DA. 4% (monomer mixture basis) Genocure LTM photoinitiator was added to the dispersion and mixed thoroughly. The details of fibre preparation are similar to those described in example 6 with a 110 micrometers die. Fibres of continuous length of several meters were separated from the water, washed and dried. The resulting HA/polymer fibres have circular cross section and diameters between 70-120 micrometers.

Example 10 - silica/polymer fibres produced in air without sheath

A UV curable dispersion containing 40 vol.% silica powder (Aerosil ox50, Evonic Degussa, Germany) and 60 vol.% resin was provided. A monomer mixture with composition as described in example 1 was used. 4% Genocure LTM photoinitiator (monomer mixture basis) was added to the dispersion and mixed thoroughly. A plastic bottle containing the dispersion was equipped with a die where the liquid exits through a 3mm hole which then tapers up to a final outer opening of 5 mm. The bottle was coated with aluminium foil to shield the dispersion from UV radiation. 3 UV lamps (similar to those described in example 1) , spaced 10 cm apart, were arrange in a vertical configuration, providing an intense UV radiation zone of ~75 cm. The bottle was placed such that the die was located 5-10 cm above the upper most UV lamp. Under this configuration, the gravity induced flow produced a cone with its minimum diameter close to the top of the UV zone. The dispersion was extruded with a velocity of 1-2 m/s. A non woven web, consisting of relatively thin fibres, 100-200 micrometers in diameter formed and collected on an aluminium foil which was placed at the bottom of the UV zone. The final curing step of the fibres occurred at the web, without affecting fibre dimensions. Similar results are obtained when the the bottle was replaced by a beaker and the dispersion is poured in an angle through a wide mouth opening.

This example demonstrates that with this current setup, high throughput fibre production with curing/hardening time scale well below 1 second is available. The curing time scale can be significantly reduced by higher intensity lamps, more reactive monomers, optimization of UV curable dispersions and UV setup. Especially notable reduction in curing time is expected for extrusion setups producing fibres in the micrometer and sub-micrometer range.

Example 11 - silica/polymer, HA/polymer and alumina/polymer elongated composite fibres obtained with dynamic sheath process

The dispersion of example 1 was used. The ex- trusion and curing setup of example 1 was used with some modifications as described below. All processes are done at room temperature.

The die consists of two sections. The first is a stainless steel T shape tube having an ID of 3 mm where the water and dispersion flows are combined. The dispersion enters the water stream through a concentrically placed stainless steel needle (0.34 mm ID and 0.6 mm OD) which ends 2-3 mm before the 3 mm tube ends. The combined water/dispersion stream enters the second part of the die which consists of 3.5 mm ID, 20 cm long plastic tube transparent to UV radiation where the dispersion cures to a fibre by UV radiation. The cured fibre exits the plastic tube through a tip which is tapered to 1.5 mm diameter into a bath of pseudostatic water sheathing fluid. Two UV sources similar to those described in example 10 are vertically positioned around the plastic tube and glass beaker. The average velocity of the dispersion in the 0.34 needle was kept at 1.4 cm/s and the flow rate of water in the range of 50-100 ml/min. With dispersion Viscosity of 0.8 Pa-s (23°C, 100s^"1) and water as a dynamic sheathing liquid the viscosity ratio of sheath to dispersion is 1/800. Under these conditions a continuous silica/polymer fibre having diameters between 60-90 micrometers is obtained with a velocity of ~25 cm/s. This represents a reduction of fibre diameter by a factor of 3.8-5.7 from the nominal 0.34 mm needle diameter obtained by the use of dynamic sheathing fluid. The use of water sheath is economically advantageous. Most of the water can be used again after inexpensive cleaning processes.

Additional experiments were carried out in an extrusion setup similar to the one described above, only in that the (stainless steel) needle delivering the dispersion had ID and OD of 160 and 310 micrometers, respectively. The water and dispersion were combined in a 0.5 mm tubular opening in a brass block into a co-flowing stream. The co-flowing 0.5 mm diameter region was 3 mm long. The stream passes through a 3 mm long 2 mm diameter outlet before exiting the brass die into a UV illuminated beaker of water. The beaker and curing setup were similar to those described in example 1. In one experiment the HA dispersion of example 9 was used and in another experiment the alumina dispersion of example 2 was used. In both experiments the velocity of the dispersions was varied between 1-10 cm/s and of flow rate of the water dynamic sheath up to about 0.33 cm3/s (average velocity of 250 cm/s) . In both examples long composite fibres around 40-60 micrometers were obtained. Shorter fibres

(several mm in length) with diameters down to 10-20 micrometers (yet circular cross section) were also reproducibly obtained at the high end of water flow rate described. Above this range, the turbulence in the water stream disintegrates the dispersion to smaller sections.

Example 12 - silica/polymer fibre web with dynamic air sheath

A UV curable dispersion containing 35 vol . % silica powder (Aerosil ox50, Evonic Degussa, Germany) and 65 vol.% resin was provided. A monomer mixture with composition as described in example 1 was used. The viscosity of the dispersion (without photoinitiator) was 1.1 Pa-s (23°C, 100s^"1) . In order to increase the viscosity of the dispersion, 10% (dispersion basis) PEG polymer (sigma Aldrich, molecular weight of 3500 g/mol) was added to the dispersion and mixed thoroughly to obtain a paste. 5% Genocure LTM photoinitiator (monomer basis) was added to the paste and mixed thoroughly. For viscosity measurements, an equivalent amount of ethanol replaced the photoinitiator in the paste composition in order to avoid curing in the viscosimeter . The paste viscosity (10Os^"1) was 9 Pa-s and 2 Pa-s at 23⁰C, and 4O⁰C, respectively. The extrusion and curing setup of example 11 was used with two UV lamps. The die consisted of a stainless steel T shape tube having an ID of 3 mm where the air and dispersion flows are combined. The paste enters the air stream through a concentrically placed stainless steel needle (0.34 mm ID and 0.6 mm OD) . The outlet of the needle delivering the dispersion was positioned 0.5-1 mm before the end of the 3 mm tube (air outlet) . Air with static inlet pressure of 8 bars (gauge) was used. All operations were carried out at room temperature.

Paste velocity through the 0.34 mm needle was 2 cm/s. At zero or at low air sheath velocities, the paste did not form continuous fibres. A dripping behav- iour was observed. When the air flow rate was raised to the range of 250-2000 1/h (10-80 m/s) long fibres formed at the die and collected at a distance of 10-30 cm from the die on an aluminium foil. At larger distances only small drops were collected due to breakup of the fibre. The fibres cured shortly after deposition on the foil and were discrete or produced a web when the foil moved or held static with respect to the die, respectively. The fibre diameter was 20-100 micrometers.

In an additional experiment the dispersion of example 1 was used with 2.5% TPO as photoinitiator . The extrusion system was similar to that described above. A similar die setup was used only the needle delivering the dispersion had 410 micrometer ID and 700 micrometer OD. The dispersion outlet needle was positioned 1-2 mm outside the tube outlet delivering the air stream. Two UV lamps, (similar to those described in example 1), one placed above the die and one in the side illuminated the area below the die. The dispersion velocity through the 0.41 mm tube was 2-5 cm/s. A dripping behaviour was observed at zero or low air sheath velocity. When the air flow rate was raised to the range of 10-70 m/s long fibres formed at the die and collected at a distance of 2-15 cm from the die on an aluminium foil or Teflon tray. At larger distances only small drops were collected due to breakup of the fibre. The fibre web could be removed easily from the Teflon tray. The fibre diameter range was 20-100 micrometers.

This example shows that fine non-woven composite fibres are available using high velocity air sheath processes at room temperature.

Reference list for figures:

E. U. Extrusion Unit; CU. Curing Unit P. U. Purification Unit; A. U. Assembly unit D. U. De-binding Unit: S. U. Sintering Unit F. U. Finishing Unit; DS. F. Dynamic sheathing fluid

PS. L. Pseudo-static sheathing liquid disp. 1 Dispersion disp. 2 Dispersion (different from 1) SL Structuring liquid

R Reservoir;

M/S Mask/Shutter

P Feeding device / Pump;

D Exit Die L Radiation device (Lamp) ;

LS Laser/focused beam unit;

S Substrate

Claims

Claims :

1. An extrusion process for producing shaped composites, said shaped composite being selected from the group consisting of unstructured, structured or micro- structured fibres, tubes, tapes and sections thereof, said extrusion process comprising the steps of a) providing a first dispersion, which comprises i) one or more inorganic particles, ii) one or more monomers, oligomers and/or polymers curable by electromagnetic radiation; iii) optionally one or more initiators, responsive to electromagnetic radiation, iv) optionally one or more surfactants, v) optionally one or more diluents; then b) processing said dispersion through a die; then c) subjecting the obtained, non-hardened material to a curing step initiated by electromagnetic radiation; then optionally d) subjecting the obtained material to a purification step, then optionally e) subjecting the obtained material to an assembly step; wherein the concentration of component (i) in said dispersion is above 1 vol.%, and wherein step b) and / or step c) is optionally aided by a sheathing fluid.

2. The process of claim 1, wherein step b) is aided by a dynamic sheathing fluid passing the die along with said dispersion.

3. The process of claim 1, wherein step c) is aided by a pseudo-static sheathing fluid which is arranged be- hind the die.

4. The process of any of the preceding claims, wherein said inorganic particles (component i) have an aver- age diameter in the range of 1 nanometer to 10 micrometer.

5. The process of any of the preceding claims, wherein said monomers, oligomers and/or polymers (component ii) are selected from the group consisting of acry- lates and poly-acrylates .

6. The process of any of the preceding claims wherein in step b) the viscosity of said dispersion (at the temperature of the process and shear rate at the die) is a) below 100 Pa*s (preferably below 10 Pa*s) provided the process is aided by a sheathing fluid which is a liquid or b) below 1000 Pa^«s (preferably below 100 Pa^»s) provided the process is aided by a sheathing fluid which is a gas or c) below 1000 Pa*s (preferably below 100 Pa^»s) provided the process is not aided by a sheathing fluid.

7. The process of any of the preceding claims, wherein the viscosity of said dynamic sheathing fluid is in the range of 1/10000 to 10, preferably in the range of 1/100 to 10 fold the viscosity of said dispersion and wherein the viscosity of said pseudo-static fluid is above 0.3 mPa»s .

8. The process of any of the preceding claims wherein the curing step c) uses radiation in the ultraviolet and / or visible spectrum.

9. The process of any of claims 2, 4 - 8, wherein the curing step c) is performed by a laser beam; or by a flood exposure unit equipped with a mask and optionally a shutter.

10. The process of any of the preceding claims, wherein in step a) said first dispersion is complemented by one or more additional fluids; said additional fluids are independently selected from one or more of the following groups: a) a second dispersion, comprising i) one or more organic and/or inorganic particles, preferably inorganic particles, ii) one or more monomers curable by electromagnetic radiation, and optionally one or more oligomers and/or polymers, which are either non-curable or curable by electromagnetic radiation, iii) optionally one or more initiators, responsive to electromagnetic radiation iv) optionally one or more surfactants, v) optionally one or more diluents, and wherein said second dispersion differs in its composition from said first dispersion; b) a structuring fluid curable by electromagnetic radiation, comprising i) one or more monomers, curable by electromagnetic radiation, and optionally one or more oligomers and/or polymers which are either non-curable or curable by electromagnetic radiation, , ii) optionally one or more initiators, responsive to electromagnetic radiation, iii) optionally one or more surfactants, iv) optionally one or more diluents; c) a non-curable structuring fluid, comprising i) optionally one or more non-curable oligomers and/or polymers ii) one or more diluents.

11. The process of claim 10, wherein the particles in fluid of group a) are chosen from the group of component i) as defined in claim 1.

12. The process according to any of claims 10 to 11, wherein the fluid of groups (a) and (b) contains or essentially consists of monomers, oligomers and / or polymers of acrylates or meth-acrylates .

13. The process according to any of claims 10 - 12, wherein the fluid of group c) has a viscosity in the range of 1/10000 to 10, preferably 1/500 to 10 fold the viscosity of said first dispersion.

14. The process of any of the preceding claims, wherein the purification step d) comprises one or more washing steps.

15. A process for producing shaped inorganic articles, said shaped inorganic article being selected from the group consisting of unstructured, structured or micro-structured fibres, tubes, tapes and sections thereof, comprising the steps according to any of the preceding claims followed by a de-binding step (step f) •

16. The process according to claim 15, wherein step f) comprises heating the obtained material.

17. The process according to any of claims 15 or 16 followed by a sintering step (step g) .

18. A manufacturing device for manufacturing a shaped composite in the form of unstructured, structured or micro-structured fibre, tube, tape and sections thereof, particularly an extruder, comprising a) an extrusion unit comprising an exit die, and b) a curing unit comprising an electromagnetic radia- tion source, wherein said exit die is in fluid communication with a reservoir of a first dispersion, with a reservoir of a sheathing fluid, optionally with one or more reservoirs of additional liquids, and wherein said exit die defines a cross section for said shaped composite encompassing an outer surface and an inner surface, and wherein said exit die is arranged to provide at the outer surface said sheathing fluid and at the inner surface said first dispersion and said optional additional liquid(s), and wherein the curing unit is located directly behind said exit die.

19. The manufacturing device according to claim 18, wherein the curing unit comprises either a unit comprising a focused laser beam or a unit comprising a flood exposure unit optionally equipped with a mask and / or a shutter.

20. A manufacturing device for manufacturing a shaped composite in the form of an unstructured, structured or micro-structured fibre, tube or tape or sections thereof, particularly an extruder, comprising a) an extrusion unit comprising an exit die, b) a curing unit comprising an electromagnetic radiation source, and c) a reservoir of a sheathing fluid wherein said exit die is in fluid communication with a reservoir of a first dispersion, optionally with one or more reservoirs of additional liquids, and wherein said exit die defines a cross section for said shaped composite encompassing an outer surface and an inner surface, and wherein said reservoir of a sheathing fluid is arranged to provide said sheathing fluid in a pseudo- static fashion to said exit die, and wherein said reservoir of sheathing fluid is arranged directly be- hind said exit die.

21. The manufacturing device according to any of claims 18 to 20, wherein extrusion unit and curing unit are arranged in one housing.

22. The manufacturing device according to any of claims 18 to 20, wherein said curing unit and said reservoir of a sheathing fluid are arranged in one housing.

23. The manufacturing device according to any of claims 18 - 22 comprising a) an extrusion unit comprising an exit die; followed by b) a curing unit comprising an electromagnetic radiation source; optionally followed by c) a purification unit, optionally followed by d) an assembly unit; optionally followed by e) a debinding unit, optionally followed by f) a sintering unit, optionally followed by g) a finishing unit whereby at least one of the units c) to g) is present in addition to unit a) and b) .

24. A shaped composite in the form of an unstructured, structured or micro-structured fibre, tube, tape or sections thereof, obtainable by a process according to any of claims 1 - 14.

25. A shaped inorganic article in the form of an unstructured, structured or micro-structured fibre, tube, tape or sections thereof, obtainable by a method according to any of claims 15 - 17.

26. A process according to any of claims 1- 17, characterized in that said fibres, tubes, tapes or sections thereof are deposited before step c) in or on a substrate to form a three dimensional structure ("deposition process") .

27. A process according to any of claims 1- 17, characterized in that said fibres, tubes, tapes or sections thereof are deposited during step c) in or on a substrate to form a three dimensional structure ("depo- sition process") .

28. A manufacturing device for manufacturing a shaped article, particularly a deposition device, a) said device comprising a device according to any of claims 18 - 23 and b) additionally a unit capable of moving a substrate with respect to the exit die, c) said shaped article comprises a supported or unsupported three dimensional structure, wherein said 3d structure is composed of unstructured, structured or microstructured fibres, tubes, tapes and sections thereof obtained by the method of claim 1, d) said substrate is within the curing unit.

29. A shaped article in the form of a three dimensional structure composed of unstructured, structured or micro-structured fibres, tubes or tapes or sections thereof, either on a subtrate or self-supporting, ob- tainable by a method according to any of claims 26 - 27.