DE102005056491B4 - Process for producing elements, in particular having at least one dimension in the micro or nano range, and correspondingly produced element, in particular micro or nano hollow fiber - Google Patents

Abstract

method for producing a small-sized element in at least a dimension, where the element ranges with different physical and / or chemical properties, characterized that at least two pourable and / or sprayable and / or extrudable and / or spinnable Masses are made with nanoparticles, with the masses out consist of the same starting materials and in their composition differ in that the mean size of the nanoparticles at least a starting material of a mass on average greater than the corresponding mean size of the nanoparticles the other mass is.

Description

The The present invention relates to a method of manufacturing elements, in particular with at least one dimension in the micro or nano range, according to the generic term of claim 1 and a correspondingly manufactured element.

at the production very thin Elements or elements with thin ones walls as in particular hollow fibers, the various properties in individual Layers or areas should often cause problems on. So require - in case extruding (spinning) a hollow fiber having at least two different wall layers in the finished state of the hollow fiber have different properties, in one operation - the different Crowds for the individual layers frequently different processing temperatures, so that in the production complicated, very expensive spinnerets used with different temperature zones for the individual masses or compromises in the temperature used have to, which the quality affect the hollow fiber. The same applies to the production of other geometries and / or other manufacturing processes which require a heated tool.

One Another problem can occur in having two materials with different properties, eg. With regard to the electrical Conductivity, which is directly related to the thermal conductivity, and / or the Permeability (dense, semipermeable or permeable), only with difficulty with each other are connectable, so there is a risk that the individual layers with different properties again, at least in some areas separate each other.

From the DE 100 23 456 A1 For example, a method of producing hollow fibers having an inner diameter of 10 nm to 50 μm is known. In this case, a fiber made of a first, degradable material is provided with at least one coating of at least one further material, for example by means of a CVD or PVD process, and then the first material degraded again, for example. By means of a thermal, chemical, photochemical, biological, radiation-induced method or by plasma, ultrasound, hydrolysis or extraction with a solvent. The walls can also consist of several different layers.

In the DE 29 52 927 C2 is the production of hollow fibers from a polymer solution containing inorganic material, in particular hollow metal fibers, described, wherein the hollow fibers may have at least one substantially non-porous, compact layer. The dimensions of the finished hollow fibers are in the following ranges: outer diameter up to 600 microns, inner diameter of 100 to 400 microns and thickness of the compact layer 4 to 50 microns. The weight ratio in the starting material polymer solution of inorganic material and polymers in this case is in the range of 3.5 to 15. The polymer solution is extruded at temperatures of 15 ° C to 100 ° C by spinnerets. Thereafter, coagulation takes place, for example in a coagulation bath. If necessary, stretching and / or tempering takes place after coagulation. This is followed by drying, in which the organic polymers are removed, followed by sintering. In this case, the finished hollow fiber may have a compact, substantially non-porous layer on the fiber outer surface, the fiber inner surface or within the wall structure. The wall structure can be changed by the pumping speed at a given winding speed, by the amount of flowing medium injected into the bores, by the degree of stretching. A compact layer on the outer surface of the fiber wall can be obtained by using a very mild coagulant or a very low concentration in the coagulating bath. A compact layer on the inside surface of the fiber wall can be obtained by using a very mild coagulant (or low concentration) in the flowing medium injected into the bore of the nozzle. A compact layer inside the fiber wall can be obtained by using a high performance coagulant both in the coagulation bath and in the flowing medium injected into the well. The hollow fibers produced in this way can be used, for example, for a hydrogen diffusion cell or a fuel cell.

outgoing from this known prior art, lies the present invention The object of the invention is an improved process for the production a corresponding element to provide.

These The object is achieved by a method with the features of claim 1. Advantageous embodiments are the subject of the dependent claims.

According to the invention, a method is provided for producing an element with a small dimension in at least one dimension, in particular in the micro or nano range, the element having regions with different physical and / or chemical properties, and at least two castable and / or sprayable ones for the production and / or extrudable and / or spinnable compositions with nanoparticles ago in which the masses consist of the same starting materials and differ in their composition in that the average size of the nanoparticles of at least one starting material of one mass is on average larger than the corresponding mean size of the nanoparticles of the other mass.

For the production of the element is preferably a binder, in particular very pure form (ultrapure), containing particles whose average dimensions are the same size as those of the nanoparticles, which make up the main component of the element. In connection with the binder and optionally other additives, preferably also are the same size like those of the nanoparticles, which are the main component of the element turn out to be casting, Injection, extrusion and / or spinning masses produced, such as. Dry melt-spinning masses, Granules Thermoplastic spraying or spinning materials. Here are the Compositions preferably skin-forming.

By The use of nanoscale particles can reduce the energy requirement become. So energy savings in plasticizing in consequence a reduction of the melting point of 10 to 25% possible. Further is for the removal of the binder requires less energy (15 up to 30%). Even in a subsequent sintering process can by the Use of nanoscale particles to save energy (10 to 25%). The lowering of the melting point also causes a lower thermal stress on the molds, such as spinnerets, and extended thereby their life. Likewise, the residence times at the individual steps in which a thermal treatment takes place, and thus the throughput times are reduced, so that the productivity is increased.

Lie the particles of one or more of the materials used as Agglomerates, these agglomerates are processed before processing, preferably by means of ultrasound, dissolved.

The nanoparticles are preferably inorganic particles, preferably metals, metal compounds, metal hydrides, oxides, non-oxides, sulfides, sulfones, hydrides, nitrides, carbides and / or carbonates, particularly preferably of SiO ₂ , in particular in the form of fumed silica and / or kieselguhr, Silicea, TiO ₂ , in particular in the form of anatase, rutile and / or brookite, ZrO ₂ and / or Al ₂ O ₃ , in particular in the form of corundum (α-Al ₂ O ₃ ), ruby and / or sapphire, soapstone (magnesium silicate (Mg ₃ Si ₄ O ₁₀ (OH) ₂ )), bone ash, activated carbon, diamond, in particular doped with boron, iron oxide, in particular in the form of magnetite Fe ₃ O ₄ and / or Hematite Fe ₂ O ₃ , and / or zeolite. The nanoparticles, which form an essential constituent of the element, are particularly preferably silicon dioxide (SiO ₂ ) and / or zirconium dioxide (ZrO ₂ ).

The Particle size of the nanoparticles is in the nanoscale, i. the largest occurring particle is less than 1 μm, otherwise it is an unwanted one Pollution. The particles are present in a highly pure form, i.e. in the powder there are (almost) no impurities (purity> 99.9%) and even the material composition of the individual particles is possible no trapped impurities (purity> 99.9%). The middle Particle size, like also the particle size distribution (Spread of particle sizes around the desired average particle size) essentially dependent of the properties to be achieved by the finished element.

The binder is preferably one or more biopolymers, for example blood and / or blood products, proteins, peptides, cellulose, starch, cutin, acetates, glycerols, alcoholates, resins, waxes, agar-agar, collagens, tallow, fats, Cysteines, gelatins, bone glues, cartilage glues, skin glues, rabbit glues, fish glues, ureas and / or caseins, and / or copolymers and / or polymers, in particular polyvinyl alcohol and / or polyethylenes and / or polypropylene and / or polyvinyl esters and / or polyvinyl acetate and / or Polyamines and / or polyacrylics and / or polyesters and / or polyamides and / or polyimides and / or polysulfones and / or polysulfides and / or polystyrenes and / or cellulose polymers. The binder can be added in solid form, provided that it is meltable, or in nanoscale powder form, when it is subsequently homogenized with a suitable meltable binder, more preferably with a resin, wax, urea, polyvinyl alcohol, and / or a suitable solvent. Otherwise, the presence of a sufficiently liquid, ie pourable, sprayable, extrudable and / or spinnable, state of the binder is required with which the nanoparticles, particularly preferably SiO ₂ , TiO ₂ , ZrO ₂ and / or Al ₂ O ₃ , be mixed, said nanoparticles are preferably used in conjunction with remeltable binders. The binders, more preferably bone glue and gelatin, preferably have a gelling ability of 160 bloom. The binders are preferably present in dissolved form as ready-to-process masses.

Instead of or in conjunction with a binder, a sol gel, eg. in the form of salt compounds, with which the Nanoparticles are mixed or which per se the nanoparticles contains.

Particularly preferred is the Binder to a biopolymer derived from slaughterhouse waste, such as in particular gelatin, bone glue or fat. These starting materials can be obtained in large quantities and inexpensively.

If necessary, the compositions may contain at least one solvent, with water, sulphurous acids, alcoholates, methyl chloride, acetone and / or coal sulfur (CS ₂ ) being preferably used as the solvent. Other solvents are also possible.

The mean size of the nanoparticles the two (or more) starting materials are preferably different by at least 50%, more preferably by at least 100%.

Prefers the masses are processed at the same processing temperature, i.e. the tool, for example, a spinner, simplifies, since no different temperature zones are required. Simplified as well the area in which the masses to be processed are fed to the spinning head because the same temperature can prevail in this area as well. This can be relative inexpensive Tools are used.

The Processing temperatures are preferably in the range of 35 up to 300 ° C, preferably from 42 to 230 ° C, in particular from 50 to 110 ° C and more preferably below 100 ° C.

The Both masses are preferably in one operation and / or in two temporally consecutive operations, the temporally maximally spaced from each other so long that a Formation of a skin layer on the surface of the first processed Mass is excluded, processed, i. the provision of the second area can not be considered casting or coating, since the first area is still no skin layer or so thin is designed so that it in the further production, i. the come in contact with the second mass, immediately dissolved or destroyed becomes.

Preferably The masses are equipped with a spinning head, which is a separate feeder Masses, extruded in one operation. The masses can, for example. However, also be poured directly one after another, with the masses at least during of the casting have the same processing temperature.

The finished molded element exists after removal of the binder preferably at least 30 wt .-%, in particular to 50 wt .-%, from the material of the nanoparticles, which are also nanoparticles can act from different materials, for example. Different Oxides.

For the production The compositions preferably have from 10 to 60% by weight of high-purity nanoparticles.

The Crowds for the preparation preferably has 15 to 30% by weight of sol gel, which contains high-purity nanoparticles.

Of the Binder content of the compositions is preferably 10 to 70% by weight, wherein the binder, as well as the nanoparticles, is highly pure.

Yet not cured, green elements, in particular Films or films can be shaped, in particular to hollow fibers wrap or deep-draw or wave, making a textured Foil is created. Also, individual elements can be composed, For example, in the context of winding the edges of each other Pages, for example. In the context of a sequence of layers for producing a cartonlike Elements, with the outer films flat and the middle sheet is corrugated, or within a design a honeycomb-like shape, in which individual areas of a A plurality of adjacent films are interconnected, the films so flexible are that after joining the honeycomb-like Structure is formed by pulling apart.

Prefers takes place after shaping, if appropriate also after sintering, for example by means of etching or mechanical removal, so that the lower layers of individual Targeted areas are exposed, a coating or a chemical processing of the surface, such as a sulphonation, which makes the surface ion / proton conductive. At least one area The element may also be chemically treated such that the Processability is improved. By the chemical treatment, For example, in the form of a coating, in particular the lubricity be improved, so that, for example, fibers and hollow fibers easier can be spun.

The element according to the invention is preferably an element with a small dimension in at least one dimension, in particular in the micro or nano range, the element having regions with different physical and / or chemical properties, the element consisting of nanoparticles with or without one remaining in the element Binder is formed, and the average particle size of at least the nanoparticles of a substance in different areas with different physical and / or chemical properties is different in size. Below "dimensions" are directions in a kar Thesische coordinate or a cylindrical coordinate system understood, wherein in the case of the cylindrical coordinates, the dimension of different properties is preferably the radial direction. Because the element essentially consists of nanoparticles of the same material, no problems occur during production under the same temperature conditions, so that the individual regions, in particular preferably formed by layers, are firmly, securely and permanently connected to one another.

At the Element is preferably a fiber, a hollow fiber, a film or a film, but are in principle also others Shapes possible. Preferably, the dimensions vary in the direction of one dimension only small, preferably at most around +/- 10%, in particular around +/- 6%, i. For example, in the case of a hollow fiber wall thickness hardly fluctuates and is thus essentially gradient-free.

The Element is preferably at least 30 wt .-%, in particular preferably at 50% by weight, of nanoparticles of a material. As materials for the Nanoparticles are especially inorganic materials in question, preferably metals, oxides, nitrides, carbides and / or carbonates. At the Material can be a pure substance, such as iron or Silica without any impurity (ultrapure), act, however, mixtures are also possible each region being the same (wt%) composition but differs in average particle size, which causes the different properties of the areas become.

The Areas of the element with different physical and / or Chemical properties are preferably due to individual layers formed, which are directly connected.

The Element preferably points in the direction of the dimension of the small Dimension changing Material properties on. This is, for example, in the case of films or films by the thickness of the film (Cartesian coordinate system), i. the film is passed through at least two, preferably by exactly three Layers formed. In the case of fibers, in particular hollow fibers, it is the radius (cylindrical coordinate system), where the fiber or hollow fiber also preferably by exactly three Layers is formed.

at the changing one Material property is preferably the permeability, i. a dense layer is adjacent to a semipermeable or even arranged permeable layer, and / or the electrical conductivity and / or the thermal conductivity. In this way, elements can be produced which, for example, a medium, dense layer and two outer, permeable layers.

Further For example, the middle layer can be made electrically conductive while the outer layers serve as insulators.

Prefers are at least two, more preferably exactly three, differentiable Layers provided with different particle sizes of the starting material. In this case, the outer layers preferably correspond at least in relation to one another on the average particle size of the starting material.

The mean particle dimensions of two different areas with different physical and / or chemical properties be in a range preferably from 8 to 50 nm and in the other Range of 50 to 100 nm.

Prefers If the layers are symmetrical, i. one on both sides middle layer are layers of corresponding materials and provided with appropriate material properties.

The Extension of the element in said dimension is preferably a maximum of 1 mm, in particular a maximum of 500 microns, most preferably a maximum 50 μm and most preferably at most 5 microns or even a maximum of 500 nm. The layer thicknesses, i. the smallest dimension of each of the areas with different physical and / or chemical properties, is preferably between 500 nm and 1 μm.

The Element is preferably a hollow fiber, which is a hydraulically equivalent Inner diameter of not more than 10 mm, in particular not more than 1 mm, in particular maximum 500 μm, in particular a maximum of 50 μm, particularly preferably not more than 5 μm or even not more than 500 nm, having.

Of course, in connection with, for example, two different masses based on different average nano-particle sizes, one or more other masses, for example a third mass, can also be processed, particularly preferably in a single spinning head. Here, the second mass, which is arranged in the finished sprayed state between the first and third mass, have a balancing function, ie it is better matched in their physical and / or chemical properties to the third mass than the first mass, so that they Improved connection of first and third mass or even enabled. Of course, several off be provided equal layers, so that a slow transition is possible. However, all of the compositions are preferably high-purity compositions which have an average particle size in the nanoscale. Furthermore, the compositions are preferably processable at the same temperature, in particular spun, sprayed, extruded and / or castable.

When Use of such elements are, for example, separation membranes, For example, in fuel cells or for electrophoresis. Such elements can also as refractory and / or high-strength fibers, for example as fibers for textiles, be used. Furthermore, can the fibers for Reinforcements, as insulation, as thermal insulation materials, for example in construction be used.

The Elements themselves can For example, be coated. Furthermore, in particular according to successful manufacture of substances such as carbon, in the outside porous areas possible. The carbon storage can, for example. In the context of spraying or Immersion in blood inhibited by salts, coagulation and flushing followed by Annealing or pyrolysis take place. Is the middle layer tight, so it can with suitable choice of material an insulating solid electrolyte form while the outer layers the anode and cathode separated from the solid electrolyte and be worn. The corresponding element can be both as thin plate (Foil) and be designed as a hollow fiber, so that accordingly a bipolar plate or hollow fiber can be produced.

Also is the storage of perovskites, charcoal with magnetite and hematite, with Boron-doped diamond, gold, in particular in the form of nanoparticles, in porous outer layers possible. Especially the storage of perovskites eliminates the previous problems in coatings with perovskites, which are generally not sufficient Have durability.

The The invention will be described below with reference to several exemplary embodiments, partly with reference to the drawing, explained in more detail. This shows

l a greatly enlarged, schematically illustrated, sectioned section through a film according to the first embodiment,

2 an enlarged section through one of the film of 1 wound hollow fiber with schematically indicated layers, and

3 an enlarged, schematic representation of a helically wound hollow fiber.

A slide 1 according to the first embodiment has three layers of the same material 2 . 3 and 4 on, where the average particle size of the layers 2 . 3 and 4 differentiate between forming materials. Main component of the (finished) layers 2 . 3 and 4 is in each case nanoscale SiO ₂ , in 1 indicated by black dots. In the present case, the outer layers exist 2 and 4 from a material with corresponding average particle size, the middle layer 3 made of a material with a much smaller average particle size. As a result of the much smaller mean particle size of the middle layer 3 this layer has a greater density.

The foil 1 is made by extruding two masses by means of a special spinning head (spinnerets), which allows the uniform distribution of the two masses on three layers. The preparation, as well as the preparation of the masses, which are made from high-purity starting materials, takes place in a high-purity space, so that any contamination can be excluded and a high-purity film can be produced.

The one mass, which later becomes the middle layer 3 has, overall, a smaller average particle size than the second mass, which are the later outer layers 2 and 4 makes up. The particle size of the SiO ₂ particles of the first mass is on average 5 nm, wherein the particle size is about 99% between 1 and 10 nm, the second mass 50 nm, wherein the particle size is about 99% between 10 nm and 100 nm , The SiO ₂ particles used for the production have a purity of at least 99.9% in terms of the powder as well as on the material composition of the individual nanoparticles.

For the preparation of the respective spinning mass nanoscale SiO ₂ particles are provided with appropriate size composition in powder form, and uniformly mixed with high purity, also present in nanoscale powder form polyvinyl alcohol (PVA). Subsequently, the powder mixture is filled under high-purity conditions into separate containers, melted at a temperature of 60 ° C (serving as the binder PVA), thereby forming a viscous mass that is constantly stirred. The mass is then heated a little further and extruded through the spinner, which has been heated uniformly to 70.degree. The processing can be continuous, ie the production of a continuous film in one direction is possible.

After extrusion, a thin layer of skin forms on the outer sides of the raw film within a very short time, which prevents sticking dert and facilitates the transportability and processability of the raw film. Following the extrusion, the green foil can be treated as in the DE 29 52 927 C2 disclosed, the entire disclosure content is expressly included, so for example, run through a Koagulierbad, stretched or otherwise formed, so that in particular the thickness can be reduced. The foil 1 in the present case has variations in thickness of not more than 6%, ie it is essentially gradient-free. The thickness of the film 1 is according to the first embodiment, 500 microns, wherein the outer layers each about 100 microns and the middle layer is about 300 microns thick.

After the production and, if necessary, shaping of a so-called green film 1 The same can be fired, ie it produces a so-called Bräunling removal of the binder and sintering of the film. As a result of the different particle sizes of the individual layers, a sealing burn of the middle layer takes place at a temperature 3 in which the smaller particles are arranged, while the two outer layers 2 and 4 in which the larger particles are arranged, remain semipermeable. In addition, the middle layer 3 electrically conductive while the outer layers 2 and 4 are not electrically conductive, so serve as insulation, so that by a single material, namely SiO ₂ , a film 1 can be made with different layers and different properties of the layers.

Alternatively, or in addition to firing, another treatment of the film may be 1 For example, the surfaces or one of the surfaces may be coated. Thus, another particularly preferably nanoscale adhesive lubricant and release agent, in particular bone ash, soapstone, silicon, carbon, polyvinyl alcohol, Teflon and / or silicone oils can be applied to the surface. This improves the processability.

For the production of hollow fibers, the film 1 , especially in the green state, cut into strips and wound into hollow fibers, wherein the strip sides are connected to the adjacent strip sides, for which, for example, a binder, in particular the same, that also for the production of the film 1 used, can be used to dissolve the surface of the strip side, so that a gluing is possible and a - if not later recognizable - seam 5 arises, as in 2 indicated. The seam 5 may be parallel to the longitudinal axis of the hollow fiber when rolled along the longitudinal axis of the strip (see. 2 ).

The Foil can also be cut into narrow strips, which are then on further processed, for example spun into threads and then entangled can be.

In 2 are the individual layers 2 . 3 and 4 a hollow fiber 1' illustrated by concentrically arranged circles. In reality, however, the transition from one layer to the adjacent layer is not in the form of a precisely definable, flat surface, but the finer material fills in unevenness of the coarser material, so that a total of a narrow contact area, wherein the real contact surface of the adjacent layers significantly larger than the theoretical, flat contact surface. This applies to all embodiments described below, even if not discussed in detail at the appropriate places.

In the manner described above, a plurality of juxtaposed strips can be wound into a larger diameter hollow fiber. However, it is a helical arrangement of one or more strips possible, as in 3 shown schematically, so that the seam or seams extend helically around the longitudinal axis of the hollow fiber.

In all cases can endless hollow fibers are formed by applying individual strips. Are over the Scope several strips provided, so should the individual joints the attached strip in the longitudinal direction be offset from each other. After the preparation of the hollow fibers can the same - accordingly the green Slide - too Bräunlingen be burned.

Also in this case, the surface may, preferably after the preparation of the hollow fibers are coated. So can on the surface another especially preferred nanoscale adhesive slip and release agents, in particular bone ash, soapstone, silicon, Carbon, polyvinyl alcohol, Teflon and / or silicone oils applied become. This improves processability, especially spinnability the hollow fibers.

According to the second embodiment, according to which the same starting materials are used as in the first embodiment, another spinner is used, with which directly multilayer hollow fibers can be produced. Here, via a corresponding arrangement and number of channels, the first spinning dope as the inner layer, the second dope as the middle layer and in turn the first dope arranged as an outer layer distributed annular, according to the illustration of 2 However, the transitions are seamless, ie as a result of the same material - apart from the variation of the mean nanoparticle diameter, whereby a certain spread is present in every mass - not clearly recognizable. The processing temperature corresponds to that of the preferred embodiment.

By Blowing in (high purity) air over the Spinner head in the lumen of the resulting hollow fiber becomes a sticking of the inner surfaces during the Production prevented. In place of air can also be another Gas or gas mixture or even - especially preferred - steam be used. Furthermore, can be due to the pressure difference between the in the lumen prevailing pressure and the ambient pressure the dimensions the hollow fiber, namely the diameter (enlarge) and affect the wall thickness, influence. The wall thickness like Also, the diameter (reduce) can be further by pulling affect the hollow fiber.

The finished, fired hollow fiber has according to the second embodiment an outer diameter of 10 μm and an inner diameter of 5 μm. The individual layers have - in difference to the first embodiment - each a thickness of approximately 1 μm. The hollow fiber has textile properties, i. she is special Can be processed and knotted by means of textile processes. These too Hollow fiber can be coated according to the first embodiment so that they are easier to process, especially spinnable, is or gets special properties.

Around thin films to receive, according to one third embodiment, which so far not mentioned in detail below the previously described second embodiment matches, over the spinner blown high purity air, so that the extruded Hollow fiber is expanded until the wall thickness has the desired film thickness. Thereafter, the film tube thus formed is slotted and thus produces a three-layered film. Also in this case can be in place from air also a gas or gas mixture or steam can be used.

According to one another embodiment, not closer is shown in the drawing, is used as a binder bone glue used in conjunction with gelatin. As nanoparticles serve according to the second embodiment Zirconia particles (as stabilized, which additives - use for BZ). in the The following is the zirconia particles including additives as Nanoparticles reference. The mean particle diameter of the nanoparticles is for the first spinning mass 5 nm, the particle diameter being about 99% between 1 and 10 nm, and for the second dope 10 nm, wherein the particle diameter to about 99% between 5 nm and 20 nm.

Of the Bone glue with the gelatin are made to process are heated to a temperature of 60 ° C before processing. Then be the corresponding nanoparticles are added and each at a constant Temperature of 60 ° C mixed well with the bone glue. As in the second embodiment described, the two masses with the help of an appropriate evenly Heated to 60 ° C Spinnkopfs processed, with over a corresponding arrangement and number of channels the first dope as inner layer, the second dope as the middle layer and turn the first dope as an outer layer annular is distributed. Due to the relatively large overlap of the Scattering of the particle dimensions results in a very good and also extreme loads exposable connection of the different Layers.

A Post-processing can be done, but is usually not required.

As well can be a suitably produced green, in an aftertreatment sulfonated hollow fiber for a fuel cell can be used.

A Such hollow fiber can - in particular when used as nanoparticles one or different metal oxides be - in a fuel cell can be used, for which the hollow fibers are fired.

According to one another embodiment is Gelatin in combination with diatomaceous earth to (full) fibers with a Core (core diameter about 1 mm) and a cladding layer (layer thickness approx. 200 μm) extruded, with the core of average larger diatomaceous earth nanoparticles is formed. The mean particle diameter of the nanoparticles in the core amounts 90 nm, wherein 90% of the particles have a diameter of 80 to 100 nm exhibit. The mean particle diameter of the nanoparticles of the Sheath layer is 40 nm, 90% having a particle diameter of 20 to 60 nm. The processing temperature is in this case 80 ° C. After cooling the fiber is solid. The fiber thus produced having one present Circular cylindrical cross section can be used for flame retardant textiles be used for what they can be spun and, for example, subsequently woven.

Claims (30)

A method for producing a small-sized element in at least one dimension, wherein the element has regions with different physical and / or chemical properties, characterized in that at least two castable and / or sprayable and / or extrudable and / or spinnable masses are prepared with nanoparticles, wherein the masses consist of the same starting materials and differ in their composition in that the average size of the nanoparticles of at least one starting material of a mass on average greater than the corresponding average size of the nanoparticles of other mass is. Method according to claim 1, characterized in that that is the mean size of the nanoparticles of the two starting materials differ by at least 50%. Method according to claim 1 or 2, characterized that the masses processed at the same processing temperature become. Method according to one of the preceding claims, characterized characterized in that the two masses in one operation and / or in two temporally consecutive operations, the temporally maximally spaced from each other so long that a Formation of a skin layer on the surface of the first processed Mass is avoided, processed. Method according to one of the preceding claims, characterized characterized in that the masses with a spinning head, which is a separate feed envisages the masses being extruded in one operation. Method according to one of claims 1 to 4, characterized that the masses are poured successively, with the masses at least while of the casting have the same processing temperature. Method according to one of the preceding claims, characterized characterized in that the finished molded element after removal of the binder to at least 30 wt .-% of the material of the nanoparticles consists. Method according to one of the preceding claims, characterized characterized in that the masses 10 to 60 wt .-% high purity nanoparticles exhibit. Method according to claim 8, characterized in that that as nanoparticles metals, metal compounds, metal hydrides, Hydrides, oxides, non-oxides, nitrides, sulfides, sulfones, carbides and / or carbonates are provided. A method according to claim 9, characterized in that as nanoparticles particles of SiO ₂ , fumed silica, kieselguhr, Silicea, TiO ₂ , anatase, rutile, brookite, ZrO ₂ , Al ₂ O ₃ , corundum (α-Al ₂ O ₃ ), Ruby, sapphire, soapstone, bone ash, activated carbon, diamond, diamond doped with boron, iron oxide, magnetite, Fe ₃ O ₄ , hematite, Fe ₂ O ₃ , and / or zeolite are provided. Method according to one of the preceding claims, characterized characterized in that the masses have 15 to 30% by weight of sol gel, which contains high-purity nanoparticles. Method according to one of the preceding claims, characterized characterized in that the masses 10 to 70 wt .-% high-purity binder exhibit. Method according to claim 12, characterized in that that as binders polymers, polyvinyl alcohol, celluloses, acetates, Strengthen, Glycerines, alcoholates, resins, waxes, agar-agar, proteins, collagens, Tallow, fats, cysteine, gelatin, bone glue, cartilage glue, skin glue, Hare glues, fish glues, ureas and / or caseins serve. Method according to claim 12 or 13, characterized in that a fusible binder is used as the binder. Method according to one of the preceding claims, characterized characterized in that the masses contain at least one solvent. A method according to claim 15, characterized in that as solvent water, sulfurous acids, alcoholates, methyl chloride, acetone and / or coal sulfur (CS ₂ ) is provided. Method according to one of the preceding claims, characterized characterized in that a sulphonation takes place. Element produced by a process according to claims 1 to 17, wherein the element areas with different physical and / or has chemical properties. Element according to claim 18, characterized that the element at least to 30 wt .-% of nanoparticles from a Material exists. Element according to claim 18 or 19, characterized in that the regions of the element with different physical and / or chemical properties individual layers ( 2 . 3 . 4 ), which are directly connected. Element according to one of Claims 18 to 20, characterized that the element changes in the direction of the dimension of small dimension Has material properties. Element according to claim 21, characterized that the changing one Material property is the permeability. Element according to claim 21 or 22, characterized that the changing one Material property, the electrical conductivity and / or the temperature conductivity is. Element according to one of Claims 19 to 23, characterized in that the nanoparticles are formed by silicon dioxide (SiO ₂ ) and / or zirconium dioxide (ZrO ₂ ). Element according to one of Claims 19 to 24, characterized in that at least two differentiable layers ( 2 . 3 . 4 ) with different particle sizes of a material are provided. Element according to claim 25, characterized in that three layers ( 2 . 3 . 4 ), the outer layers ( 2 . 4 ) correspond to each other at least in relation to the average particle size of the material. Element according to one of Claims 19 to 26, characterized that the element is a fiber, hollow fiber or a foil. Element according to one of Claims 19 to 27, characterized that at least one area the element is chemically treated. Element according to one of Claims 19 to 28, characterized that the extent of the element in the dimension is a maximum of 1 mm, is. Element according to one of Claims 19 to 29, characterized that the element is a hollow fiber, which is a hydraulically equivalent Inner diameter of a maximum of 10 mm.