Mix for the production of microporous structures

Abstract

The invention relates to an easy-to-handle ready mix of a polymer preparation, in particular for producing porous or microporous structures, the ready mix comprising a polymer substrate and a diluent, and the components of the polymer preparation fitting together in such a way that they are inseparably interlinked in a state of the ready mixture upon delivery.

Description

[0001] MIXTURE FOR THE PRODUCTION OF MICROPOROUS STRUCTURES

[0002] Description

[0003] Field of the invention

[0004] The invention relates to a ready-mixture and its use for producing microporous structures or elements having microporous structures.

[0005] Background and general description of the invention

[0006] Microporous polymer membranes can be used in many separation processes. For example, in the production of milk powder for concentrating whey protein prior to spray drying, in biotechnology for separating cells and cell fragments from fermentation broths, for microbial separation in drinking water treatment, or for purifying process media in industrial processes.

[0007] There are already established processes for producing polymer membranes. In the NI PS process (Non-solvent Induced Phase Separation), for example, a polymer is dissolved in an organic solvent, applied as a thin layer to a nonwoven fabric, or spun as a hollow fiber or thin tube. On contact with a non-solvent, often water, the polymer precipitates as a microporous structure. In contrast, in the TIPS process (Thermal Induced Phase Separation), precipitation occurs by lowering the temperature of the polymer solution. The polymer is completely dissolved at elevated temperatures, e.g., 200°C. The solubility of the polymer in the solvent / diluent is greatly reduced at lower temperatures, e.g., 160°C, so that phase separation occurs upon cooling; upon reaching the cloud point, microporous structures are formed. The porous regions are interconnected.

[0008] For example, patent DE 2 833493 C3 describes the production of microporous hollow fibers using the TIPS process. This process involves mixing molten polymer with a liquid solvent or solvent mixture in a dynamic mixer while still in a liquid state. A metering pump conveys the mixture to an extrusion die, by means of which a hollow fiber or a thin tube can be formed. This approach has several disadvantages. For example, the mixing ratio between polymer and solvent must be adjusted manually and is subject, in particular, to deviations in the respective pumps. These pump deviations typically add up to a delivery error, so that the finished product can exhibit relatively large fluctuations in terms of the number of pores, pore size, and pore composition. This is because even small deviations in the composition of the starting material can result in significant changes in the formation of microporous structures.This makes it impossible to specify exact filter performance. These deviations are particularly pronounced when only small flow rates are required, because the absolute magnitude of the pump error is always relative to the maximum flow rate, so the relative error increases disproportionately for smaller flow rates.

[0009] A further disadvantage of the solution shown in DE 2 833 493 C3 concerns the complexity of the system, which - also due to the regularly varying flow rates of the pumps - requires a high degree of process know-how for its operation, so that such a system can only be operated by a few trained employees and requires constant monitoring and adjustment of the process parameters.

[0010] German publication DE 32 05289 A1, on the other hand, deals with the production of porous bodies with adjustable total pore volume, adjustable pore size, and adjustable pore wall thickness. It proposes using a liquid "A" (castor oil, soybean oil, or palm kernel oil) to form porous bodies with a polymer. Liquid "A" serves as the "bath liquid" of a spinning tube, which is kept at a temperature below the phase separation temperature. The bath liquid is passed through the spinning tube in the same direction as the polymer. In other words, a polymer is immersed in a bath of liquid A. Furthermore, it is a strictly continuous process that cannot be interrupted or altered.This inline melt is therefore a very complex direct process with a bath liquid A, which requires a complex process setup and experienced process engineers to monitor the continuously occurring mixing process, which can change spontaneously. If, for example, the pumping capacity of the bath liquid changes (which is frequently observed in practice), the manufactured body is unsuitable because the pore size is incorrectly set. However, this can only be determined after production is complete. The manufactured body is then already ready for disposal. Monitoring the mixture is very difficult. Changes in the mixing ratio, which can easily occur due to fluctuating process parameters, cannot be recorded. Precisely specified pores are therefore impossible or difficult to achieve.Furthermore, an adjustable change in the mixing ratios between polymer and bath liquid is not possible, or requires extensive process expertise from the user. Different pores in one and the same body, which would be predefined in advance, cannot be realized with the process shown in DE 32 05289 A1.

[0011] On the other hand, filaments based on polypropylene (PP) mixed with polyvinyl alcohol (PVA) are commercially available. Even in their molten state, the two polymers do not form a homogeneous solution and form a type of emulsion. In the solidified state at room temperature, this preparation exists as a compound or polymer blend. With a suitable 3D printer, pipe sections can be printed using the FDM process. The water-soluble PVA components can be extracted using hot water. It can be observed that the pipe sections expand by up to 20% in the axial direction (z-axis, perpendicular to the printer plane) during extraction. This behavior can lead to problems such as warping or breakage of the component in complex components consisting of two materials, for example. In combination with pure PP, which practically does not expand upon contact with hot water, component sections made of these two materials can unintentionally separate from each other.As a result, these components are usually unusable.

[0012] The object of the present invention can therefore be seen as providing a method and a device that enable improved or modified production of components or objects with porous or microporous regions. In other words, preferred components or objects are those that, on the one hand, have porous or microporous regions and, on the other hand, have impermeable regions constructed integrally with the porous or microporous regions. Alternatively, furthermore, components that have an adjustable porosity.

[0013] In a partial aspect or further development of the invention, it can be considered as an aspect of the object to provide a device and a method in which the aforementioned disadvantages are taken into account or eliminated.

[0014] Thus, in yet another aspect or development of the invention, the object can be to provide a device and a method by means of which a constant component properties with regard to filter performance and pore sizes can be achieved. In another aspect, the present invention can solve the problem that it may no longer be necessary to operate the system under constant supervision by trained personnel. In yet another aspect, the invention can solve the problem of being less complex or more cost-effective than known systems, thus resulting in advantages in this regard as well.

[0015] The problem is solved by the invention defined in the independent claims. Dependent claims specify further developments and preferred embodiments of the invention.

[0016] To solve one, several, or all of the presented aspects of the problem, an easy-to-handle ready-mix of a polymer preparation is proposed, in particular for the production of porous or microporous structures. The ready-mix comprises a polymer substrate and a diluent. The diluent is intended, for example, as a solvent or diluent. In a delivered state of the ready-mix, the components of the polymer preparation are provided in such a way that they interlock, thus being inseparably bonded to one another. For example, the ready-mix is ​​provided in such a way that, in a comparatively large batch, liquid polymer substrate is mixed with liquid diluent, creating a homogeneous solution. The homogeneous solution can then be cooled, so that a homogeneous solid mass can be provided in a reservoir without separation from the solution.This cooled solid mass can then be reduced in size, for example, by granulation, into a desired shape. The homogeneous solid mass can also be provided, for example, as a filament.

[0017] In other words, a significant advantage of the ready-mixed polymer preparation presented here lies in the fact that the ready-mix is ​​specially premixed in its delivery state, thus presetting the porosity that can be built up from it without the need to monitor a multitude of process parameters. Another particularly advantageous feature is that the ready-mix is ​​in a solid state. This ensures easy handling; it can be transported and prepared for later processing in manageable portion sizes for a production facility. Such a production facility can be a single, small 3D printer or a small extrusion or spinning system that does not require any special structures, for example, for storing or preparing a melt. This means that a premixed product is available for the production facility.Because the ready-mixed product is premixed and thus ready for direct production as a single-component base, without the need for premixing in the production facility, the corresponding process steps of separate heating, regulating, and adjusting the corresponding pumps and conveying equipment, as well as the corresponding equipment, can be eliminated. The associated process know-how also no longer needs to be maintained by the production facility user. Instead, the ready-mixed product can be fed into the production facility, and the user can be confident that the desired manufacturing tolerances can be maintained.

[0018] For example, the polymer substrate in the ready-mixed mixture is already adjusted to form porous or microporous regions filled with a diluent-rich phase. This improves the "interlocking" of the polymer substrate with the diluent, creating a stable—also mechanical—bond that is only broken when the ready-mixed mixture is transferred into a solution. The solution obtained from the ready-mixed mixture is always immediately homogeneous, since the diluent is located between the polymer substrate and enters the solution directly during melting. Therefore, complex mixing of the solution may be unnecessary.

[0019] The polymer preparation can be adjusted so that it is in the solid state at room temperature, in particular in the range below 50°C, preferably in the range up to 75°C or less, more preferably in the range up to 100°C or less. The polymer preparation can further be adjusted so that it forms a solution, in particular a homogeneous solution, at elevated temperature, wherein the elevated temperature is in particular 70°C or more, more preferably 90°C or more, even more preferably 120°C or more.

[0020] The porous or microporous regions of the polymer preparation in the finished mixture have an average pore size. The average pore size of the porous or microporous regions is preferably 5 μm or smaller, more preferably 1 μm or smaller, and even more preferably 0.5 μm or smaller.

[0021] The polymer substrate and / or the polymer preparation of the ready-mix is ​​preferably hydrophobic and / or such that water is only absorbed in small quantities. For example, the compound with polypropylene and polyvinylidene fluoride is hydrophobic. Polyethersulfone with s-caprolactam, on the other hand, is typically hydrophilic and is typically extracted with water. As has been observed, the water absorption is nevertheless only slight and results in only a slight expansion of the component. Furthermore, the polymer substrate and / or the polymer preparation of the ready-mix can be adjusted such that transfer of the ready-placed ready-mix into a final product causes only slight swelling, be it a temporary swelling of the final product during its production or a permanent swelling resulting in a larger dimension of the final product, for example, a greater length.Thus, it may be preferred that the polymer preparation swells in at least one direction, preferably in all directions, in particular by a maximum of 10% of the original size or less, preferably 5% or less, more preferably 3% or less. This can prevent stresses and any associated cracks, particularly during production. For example, it can be provided that the diluent is washed out after the product has cured. In this case, the diluent can initially absorb the leaching agent to a small extent, if necessary. However, it is not desirable for the diluent to absorb the leaching agent to a large extent, since this can lead to an enormous change in length or swelling in one or more directions.This can be ideally prevented by keeping the ready-mixture according to the invention in stock, tailored to the respective process, since the swelling can also depend on the exact mixing ratio between polymer substrate and diluent.

[0022] Drying an article produced from the ready-mixed mixture can further cause shrinkage of the article, which in particular amounts to at most 10% of the original size or less, preferably 5% or less, more preferably 3% or less. For example, the shrinkage can be of a similar magnitude to the previously described swelling of the article, so that the article produced from the ready-mixed mixture has approximately the same material volume or body volume as the polymer preparation provided in the ready-mixed mixture, and volume or length changes throughout the production process are smaller than at most 10% or less based on the material volume, preferably 5% or less, more preferably 3% or less.

[0023] The polymer preparation may further comprise an organic or inorganic additive.

[0024] The polymer substrate may comprise polypropylene, polyethersulfone, or polyvinylidene fluoride, or a mixture thereof, but the list is not exhaustive. The diluent may comprise soybean oil, castor oil, carnauba wax, s-caprolactam, or a mixture thereof, but the list is not exhaustive.

[0025] The polymer preparation can comprise polypropylene as a polymer substrate in a mass fraction of at least 20 m%, preferably at least 35 m%, more preferably at least 50 m%, and / or up to 40 m%, preferably up to 55 m%, more preferably up to 65 m%. The polymer preparation can alternatively or cumulatively comprise polyethersulfone in a mass fraction of at least 10 m%, preferably at least 20 m%, more preferably at least 30 m%, and / or up to 25 m%, preferably up to 35 m%, more preferably up to 45 m%. The polymer preparation can alternatively or cumulatively comprise polyvinylidene fluoride in a mass fraction of at least 15 m%, preferably at least 25 m%, more preferably at least 35 m%, and / or up to 30 m%, preferably up to 40 m%, more preferably up to 50 m%.

[0026] The diluent may comprise a mixture of soybean oil with castor oil in a mass fraction of at least 50 wt%, preferably at least 65 wt%, more preferably at least 80 wt%, and / or up to 85 wt%, preferably up to 70 wt%, more preferably up to 55 wt%. Alternatively or cumulatively, the diluent may comprise carnauba wax in a mass fraction of at least 50 wt%, preferably at least 65 wt%, more preferably at least 80 wt%, and / or up to 85 wt%, preferably up to 70 wt%, more preferably up to 55 wt%. The diluent may alternatively or cumulatively comprise s-caprolactam as diluent in a mass fraction of at least 65 m%, preferably at least 80 m%, more preferably at least 90 m%, and / or up to 95 m%, preferably up to 85 m%, more preferably up to 75 m%.

[0027] It was found that the polymer preparation, stored as granules or filaments, with a mixture of 35% polypropylene and 65% soybean / castor oil mixture, does not form any oily deposits or sediments up to a temperature of 110°C and / or during long-term storage. In other words, it was found that the ready-mixed polymer preparation in the form described here is stable and can be stored.

[0028] The present description also covers the provision of the ready-mix as described above in one of the following advantageous forms. For example, the ready-mix can be provided as granules, powder, flakes, filament, melt cartridge, a cartridge or for use in a drum melter. In other words, the provision of the premixed ready-mix, in particular in the solid phase, allows a variety of provision forms, each of which can be adapted to a particularly suitable or particularly cost-effective form. As an example, the form of the drum melter is taken, in which the solid product from the preparation of the ready-mix can even be left in the preparation pot; it can solidify immediately there. The ready-mix is ​​then heated in portions orThe heating device melts the mixture slice by slice and feeds it into the production line. Only the amount of the finished mixture, or a slightly excess portion of it, needed for actual production needs to be melted. The remainder remains in the solid phase in the drum, making it particularly energy-efficient.

[0029] The present description also covers a method for producing an easily handled ready-mixed polymer preparation. The method comprises the steps of mixing a polymer substrate with a diluent to provide a polymer-diluent mixture, and heating the polymer-diluent mixture to a temperature above the melting temperature of the diluent. In a particularly preferred embodiment, the melting temperature of the diluent is lower than the melting temperature of the pure polymer substrate, wherein the diluent is suitable for melting the polymer substrate at its melting temperature, or at least below the melting temperature of the polymer substrate. This enables further energy savings during the production of the ready-mixed mixture, since heating only to the melting temperature is required.Of course, the present description also covers heating the polymer-diluent mixture to a temperature above the melting temperature of the polymer substrate.

[0030] The method further comprises allowing the polymer-diluent mixture to dissolve to provide a homogeneously dissolved polymer preparation. Typically, this means heating the polymer-diluent mixture to a temperature higher than the melting temperature of the diluent and / or the polymer substrate.

[0031] Cooling of the polymer preparation below a solidification temperature preferably takes place subsequently, i.e. when the homogeneous solution is established, so that the homogeneous solution solidifies.

[0032] The solidified polymer preparation can then be portioned, for example, by granulation, or by grinding it into a powder, or by flaking it into flakes, by rolling up the filament and separating it into manageable sizes, by completing the respective melt cartridge, or by sealing a cartridge or otherwise finishing it. When used in a drum melter, for example, portioning takes place during or before mixing or dissolving, since the prepared mixture can be preset in the drum and a manageable amount is introduced into the drum.

[0033] The present description also encompasses a method for producing a component from a ready-mixture, comprising the steps of providing a ready-mixture, in particular as previously described, heating at least a portion of the ready-mixture to a temperature above the melting temperature of the diluent and / or the ready-mixture and thus providing a homogeneously dissolved polymer preparation, extracting the homogeneously dissolved polymer preparation and thereby constructing the component, in particular in a monolithic design, further in particular by means of additive manufacturing. The stably storable ready-mixture has already been successfully used to produce corresponding microporous components. In terms of handling, it has proven to be extremely user-friendly and simple to handle compared to previous methods using a bath liquid.A process engineer is no longer required, as the step of continuously adjusting and monitoring the mixing ratios is eliminated. Instead, the ready-mixed product, for example in the form of granules or filaments, always provides a consistent mixing ratio.

[0034] During the construction of the component up to its completion, a change in volume or length caused by foreign matter of at most 10% of the original size, preferably of at most 5% or less, more preferably of 3% or less, can be set.

[0035] The present description further encompasses a system for producing components from a ready-mixed mixture, in particular as described above or using one of the methods described above, comprising a ready-mixed mixture reservoir for easily providing the solid ready-mixed mixture, a heating device for heating at least a portion of the ready-mixed mixture above the melting temperature of the diluent. The system further comprises a placement device for constructing the component. For example, this can be an extruder or a filament transport device.

[0036] The ready-mixed material can be provided in the system as granules and / or as a melting cartridge. The ready-mixed material reservoir can be provided as a drum. The heating device can be configured to be immersed in the ready-mixed material reservoir as a drum melter. The ready-mixed material can also be provided as a filament, and the heating device can be configured as a continuous melter.

[0037] The present description also covers a component which is manufactured from the ready-mixture described above and / or according to one of the methods described above and / or with the plant described above.

[0038] The invention presented here is therefore capable of providing a finished mixture (preparation) of polymer(s) and diluent(s) that are solid at room temperature and thus easy to handle. The preparations can be produced in various forms, with the following appearing particularly interesting: o Granules o Powder o Flakes o Melt cartridge o Melt cartridge for drum melters o Filament

[0039] In these forms, the materials are easy to process using currently available technologies. For example, a simple extruder or drum melter is sufficient to produce hollow fibers or flat membranes using suitable extrusion tools. The complex preparation of a mixture of at least two components is eliminated. This also greatly simplifies the start-up and shutdown of the extrusion system. The availability as filaments or granules makes their easy use in additive manufacturing possible. In all cases, extraction of the diluent phase is simple and involves minimal swelling, as the diluent systems consist predominantly of low-molecular-weight components. The resulting microporous structure consists of interconnected pores.

[0040] The preparations described in this specification are homogeneous solutions at temperatures where the mixture is liquid. The components of the finished mixture do not form an emulsion or blend, but rather mix homogeneously and completely. This allows for smaller pores to be created. Swelling during extraction is also significantly lower, at typically less than 3%, than with the PP / PVA polymer blend described above. Furthermore, no anisotropic swelling occurs, nor do differences in different directions occur, or they are 3% or less, during the extraction / swelling ratio. The lower molecular weight of the diluents used in this specification also plays a role here.

[0041] Specific examples of usable, tested, and highly suitable material systems include, firstly, a blend of polypropylene (polymer substrate) and soybean oil / castor oil (diluent), typically in a ratio of 35% polypropylene and 65% soybean oil / castor oil. In a second example, this may include polypropylene (polymer substrate) with carnauba wax (diluent), typically containing 35% polypropylene and 65% carnauba wax. In a third example, this may include polyethersulfone with ε-caprolactam, typically containing 20% ​​PES and 80% ε-caprolactam. In a fourth example, this may include polyvinylidene fluoride with ε-caprolactam, typically containing 25% PVDF and 75% ε-caprolactam. For the sake of clarity, it should be added that the person skilled in the art will recognize that the specific examples described in this paragraph are not limited to the specific number in question, but variations in composition are possible and are included in the present description.Examples of lower and upper limits for substance compositions are given elsewhere in this description and are also applicable to this paragraph.

[0042] A further advantage is the greater accuracy of the composition and the improved reproducibility of mixing results. For example, the diluent quantity is not the difference between different flow rates, for example, of a melt pump and a metering pump. These errors can lead to undesirable deviations in the composition of the polymer-diluent mixture, especially with small metered quantities. When microporous structures are formed, even small deviations in the composition of the mixture can result in significant changes to the microporous structure. With the procedure according to the invention, the preparation of the polymer-diluent mixture is separated in time and space from the metering or application of the molten mixture. This allows the optimal adjustment of the mixing ratios without having to consider a subsequent extrusion or spinning process.

[0043] The inventive ready-mix material can be used not only for strand extrusion and melt spinning, but also in injection molding processes (single-component and multi-component injection molding). Complex filter structures can be manufactured cost-effectively, particularly using injection molding. Components with porous and non-porous regions, or with regions of varying porosity within the same component, can also be realized relatively easily using multi-component injection molding by providing several differently composed ready-mixes simultaneously or sequentially. Overall, the provision of the ready-mix according to the invention, as described in detail here, alone represents enormous potential for further development in this field.

[0044] Injection molding, like 3D printing, is a discontinuous process which can be carried out using the ready mix (polymer mix) presented here - in contrast to conventional inline processes which can only be operated continuously. You could say that the ready mix (polymer mix) offers a "melt-on-demand" process for the production of porous structures, in which only the portion or quantity of material required for the construction of the subsequent component - or even just areas or parts of the component - needs to be prepared in molten form. This way, a component can be created with a first ready mix, a zone with little permeability, then a second ready mix - e.g. a different filament - can be inserted and this can be further processed on the same component. The additional filament or the second ready mix can therefore be used, particularly in a one-piece ormonolithic construction, with which a highly permeable zone is created. The present invention therefore further provides the possibility of operating a discontinuous process, in particular in the form of injection molding, 3D printing or melt-on-demand, for constructing a component with porous structures. The present description therefore also encompasses a discontinuous process for producing a component from a ready-mixed material, comprising the step of providing a first portion of the ready-mixed material, in particular as described in detail above. The ready-mixed material can be provided by filling the first portion of the ready-mixed material, for example granules, into a first storage container, for example.Furthermore, the step of heating the first portion of the finished mixture to a temperature above the melting temperature of the diluent and / or the finished mixture and thus providing a first complete amount of homogeneously dissolved polymer preparation is included. A first region of the component to be built is built up in a build step with the first complete amount of homogeneously dissolved polymer preparation. When the first portion of the finished mixture has been used up, or during the use of the first portion of the finished mixture, a further portion of the same finished mixture or a portion of a further finished mixture is provided. The further portion is heated to the temperature above the melting temperature of the diluent and / or the finished mixture and thus a second complete amount of homogeneously dissolved polymer preparation is provided.Subsequently, a second section of the component is built up using the second complete amount of homogeneously dissolved polymer preparation. This process can be repeated continuously, with another portion or complete amount of homogeneously dissolved polymer preparation being provided and these being processed consecutively until the component is finally completed, particularly in a monolithic, i.e., one-piece construction.

[0045] For the purposes of the present description, the provision of the first portion of the ready-mix and the provision of the second portion of the ready-mix can be interlocked in the process or system. For example, the second portion of the ready-mix can be poured into a receiver while the remainder of the first portion of the ready-mix is ​​being removed from it. Alternatively or cumulatively, the first portion of the ready-mix cannot be completely removed from the receiver because, for example, residues adhere to the walls of the receiver and these residues mix with the second portion. However, this does not represent a transition to a continuous process, even if it should result in a continuous material flow at the material application nozzle. This is because the raw material, i.e. the ready-mix, can be refilled or replenished discontinuously.In other words, the discontinuous process differs from the continuous process in that the raw material (here: the finished mixture) is not introduced or supplied into a facility (e.g., the feeder) in a constant and continuous material flow. Rather, the supply can be interrupted, i.e., discontinuous, and can, for example, be made in individual, separate portions. Such portioning, which advantageously always provides a consistent material composition of the polymer preparation, is easily implemented by modern digital machines. Monitoring the discontinued continuous material supply flow is no longer necessary.

[0046] The discontinuous process can be carried out by extraction of the homogeneously dissolved polymer preparation and / or in a monolithic construction. The discontinuous process can also be designed as an injection molding process, 3D printing, melt-on-demand, or a combination of the above.

[0047] In the following, the invention is described in more detail using exemplary embodiments and with reference to the figures, wherein identical and similar elements are partly provided with the same reference numerals and the features of the various exemplary embodiments can be combined with one another.

[0048] Short description of the characters

[0049] It shows: Fig. 1 A schematic structure of a device for processing the ready mix,

[0050] Fig. 2 is a schematic process diagram showing the preparation of the finished mixture, its subsequent

[0051] Use and manufacture of a component from the ready mix,

[0052] Fig. 3 shows another embodiment of a device for processing the ready mix with two

[0053] material stocks,

[0054] Fig. 4 with figures 4A, 4B and 4C show three component sections of components manufactured according to the invention with porosity adjusted according to the invention.

[0055] Detailed description of the invention

[0056] Fig. 1 shows an example of a spinning system 1 for the inventive production of an object 20. From a storage container 12, a preparation or ready-mix 30 according to the invention, e.g. based on polypropylene, here as granules 32, is fed to an extruder 14 and melted there. A conveyor screw 15 can be arranged in the extruder 14, which, for example, comprises the heating device 17, so that an inline heater is formed. Alternatively or cumulatively, the extruder 14 can also have a heating device 17a on the outside or on its outer walls. In yet another alternative, for the sake of completeness, the ready-mix 30 can also be heated in the storage container 12 and fed in liquid form to the extruder 14. A solution is thus formed from the ready-mix 30 in the extruder 14 at the latest. This solution conveys a metering pump 16 to an extrusion nozzle 18 which is designed to form a hollow thread or a thin tube 20.A support fluid, here N2, supplied in a controlled manner via a flow meter 22 prevents the extruded hollow fiber or tube 20 from collapsing. Cooling causes demixing (phase separation) in the wall of the extruded hollow fiber or tube 20.

[0057] Fig. 2 shows a schematic overview of a process sequence. First, the polymer substrate 102 and the diluent 104 are combined to form a polymer-diluent mixture 105. Heat energy 106 is supplied to the polymer-diluent mixture 105, for example, by means of a heating device, and the polymer-diluent mixture 105 is gradually fed to a melting step 107. Alternatively, the polymer substrate 102 can be melted separately from the diluent 104, and both components can be mixed in liquid form. However, it can be advantageous to melt the polymer-diluent mixture 105, for example, if a lower melting point develops for the mixture as a whole.This may be the case if the diluent 104 has a lower melting point than the polymer substrate 102 and the molten diluent 104 is capable of dissolving the polymer substrate 102 at a lower temperature than the melting temperature of the polymer substrate 102.

[0058] In step 110, a homogeneous solution of the polymer-diluent mixture is formed as a finished mixture. This can now be portioned in liquid form or, for example, for later use in a drum melter, cooled directly. For this purpose, heat energy is extracted in step 108. The heat cycle can be closed, for example, using heat exchangers and a recirculation step 109, so that overall little heat energy is required during production. Finally, the finished mixture forms in the solid phase in step 112 and can be converted into a ready-to-ship finished mixture 120 in a portioning step 115. The ready-to-ship finished mixture 120 is in a very easy-to-handle form, can be shipped, expires, etc.In particular, the finished mixture 120 is evenly distributed and homogenized throughout an entire batch, but can also be distributed very evenly throughout the production process, so that the subsequent user does not have to first dose the polymer substrate 102 and diluent 104 individually in their system and account for corresponding dosing errors. Rather, the user can fill the finished mixture 120 into their system in step 125, heat or melt it in step 130, and extrude or additively produce a corresponding component or object 20 in step 135. The component 20 is then dried in step 140. Overall, significantly less process knowledge is required for component production, so that production is now available to a much broader range of users.

[0059] Referring to Fig. 3, another embodiment of a system 1 for constructing a component 20 is shown. This figure is intended to schematically illustrate a discontinuous process. Two different ready-mixed mixtures 30, 30A are provided in two storage containers 12, 13. The ready-mixed mixtures 30, 30A can be provided, for example, in granular or filament form. The ready-mixed mixture 30, 30A is provided "on demand" by means of the respective metering pump 16, 16A and introduced into the reservoir 21, where it can be heated and melted by means of the heating device 17, 17A. From this point on, further processing can be carried out, for example, analogously to the system described in Fig. 1. Alternatively or additionally, the molten medium is fed to the outlet 19, wherein the outlet 19 can be configured to form a hollow fiber or a thin tube 20.A support fluid, such as N2, supplied in a controlled manner via a flow meter 22 can prevent the extruded hollow fiber or tube 20 from collapsing. Cooling causes demixing (phase separation) in the wall of the extruded hollow fiber or tube 20. In this way, a component 20 can be built up piece by piece.

[0060] Fig. 4 shows, at different microscopic magnification levels, component sections according to Figs. 4A, 4B, and 4C, with the porosity adjusted by means of the ready-mix 30 used. Thus, Fig. 4A shows, at a 1000x magnification, a first surface 24 of a component 20, which has surface pores 26 connected to internal pores 29. In the porous structure 28, the numerous pores 26, 29 are predominantly connected to one another, forming a common, connected cavity. The component 20 thus has an open-pore structure 25.

[0061] Fig. 4B shows, at a magnification of 2000x, another example of a component 20 produced from the ready-mixed material 30. In this example, too, an open-pored structure 25 of interconnected pores 26, 29 has formed. The average pore width of this configuration is, for example, approximately 0.5 μm. Finally, Fig. 4C shows, at a magnification of 5000x, a detailed view of a very porous component 20 in a component section 28, in which the open-pored structure 25 of the interconnected pores 26, 29 is clearly visible. In this example, the inner cavity of the interconnected pores 26, 29 is particularly visible. In other words, the component 20 forms a self-supporting structure with intrinsic porosity. The open-pored structure 25 is permeable, meaning it can be penetrated by material components.Figure 4 thus provides evidence that the components manufactured with the ready-mix 30 according to the invention can exhibit a desired porosity if this porosity is adjusted accordingly with the ready-mix 30. Thus, even a layperson without special prior knowledge can produce corresponding membranes, tubes, and other microporous structures or components using a simple device, such as a 3D printer, without having to resort to a very complex inline mixing process.

[0062] The material of the ready-mix 30 according to the invention can be used not only by strand extrusion and melt spinning but also by injection molding (single-component and multi-component injection molding). Complex filter structures 20 can be produced cost-effectively, particularly by injection molding. Components 20 with porous and non-porous regions, or with regions of varying porosity within the same component 20, can also be produced relatively easily using multi-component injection molding, so that the provision of the ready-mix 30 according to the invention, which is described in detail here, is seen as offering enormous potential for further development in this field. It will be apparent to those skilled in the art that the embodiments described above are to be understood as examples, and that the invention is not limited to them, but can be varied in many ways without departing from the scope of the claims.Furthermore, it is clear that the features, regardless of whether they are disclosed in the description, the claims, the figures, or otherwise, also individually define essential components of the invention, even if they are described together with other features. In all figures, the same reference numerals represent the same objects, so that descriptions of objects that may only be mentioned in one figure or at least not in all figures can also be applied to those figures and embodiments with respect to which the object is not explicitly described in the description.

[0063] List of reference symbols

[0064] 1 spinning system

[0065] 12 storage containers

[0066] 13 additional storage containers for a second ready mix

[0067] 14 extruders

[0068] 15 Conveyor screw or conveyor device

[0069] 16, 16A dosing pump

[0070] 17, 17a Heating device

[0071] 18 Extrusion nozzle

[0072] 19 Outlet

[0073] 20 hollow fiber, thin tube, object, component

[0074] 21 Template

[0075] 22 flow meters

[0076] 24 Component surface

[0077] 25 open-pored or porous structure

[0078] 26 surface pore

[0079] 28 Component cross-section with porous structure 25

[0080] 29 inner pore

[0081] 30, 30A Ready mix

[0082] 32 granules

[0083] 100 procedures

[0084] 102 Polymer substrate

[0085] 104 Diluent

[0086] 105 Polymer-Diluent Mixture

[0087] 106 Supply of heat energy

[0088] 107 Melting step

[0089] 108 Removal of heat energy

[0090] 109 Return step

[0091] 110 homogeneous solution from ready mix

[0092] 115 Portioning

[0093] 120 Ready-mixed, ready for dispatch or for filling into a plant

[0094] 125 Filling

[0095] 130 Melting the (first portion of the) ready-mix

[0096] 135 Production of a (first area of) a component (e.g. extrusion, continuous manufacturing, but also discontinuous manufacturing, additive manufacturing, injection molding, melt-on-demand)

[0097] 140 Drying of the component (in the continuous process)

[0098] 150 Melting the second portion of the ready-mix or a portion of a second ready-mix

[0099] 155 Manufacturing the second area of ​​the component

[0100] 160 Drying of the component (in the discontinuous process)

Claims

Patent claims. An easily handled ready-mix (30, 30A, 32, 120) of a polymer preparation, in particular for producing porous or microporous structures (20) or a component (20), comprising a polymer substrate (102) and a diluent (104), wherein the constituents of the polymer preparation interlock in a delivered state of the ready-mix such that they are inseparably bonded to one another. Ready-mix (30, 30A, 32, 120) according to the preceding claim, wherein the polymer preparation is in the solid state in the delivered state, and / or wherein porous or microporous regions filled with a diluent-rich phase are formed in the polymer substrate (102).The finished mixture (30, 30A, 32, 120) according to any one of the preceding claims, wherein the polymer preparation is in the solid state at room temperature, in particular in the range below 50°C, preferably in the range up to 75°C or less, more preferably in the range up to 100°C or less, and / or wherein the polymer preparation forms a, in particular homogeneous, solution at elevated temperature, wherein the elevated temperature is in particular 70°C or more, more preferably 90°C or more, even more preferably 120°C or more. The finished mixture (30, 30A, 32, 120) according to any one of claims 2 or 3, wherein the porous or microporous regions have an average pore size, wherein the average pore size of the porous or microporous regions is preferably 5 pim or smaller, more preferably 1 pim or smaller, even more preferably 0.5 pim or smaller.Ready-mix (30, 30A, 32, 120) according to one of the preceding claims, characterized in that the polymer substrate (102) and / or the polymer preparation is hydrophobic and / or only slightly retains water, and / or that a transfer of the ready-placed ready-mix into a final product (20) causes a swelling of the polymer preparation in at least one direction, preferably in all directions, of in particular at most 10% of the original size or less, preferably 5% or less, more preferably 3% or less. Ready-mix (30, 30A, 32, 120) according to one of the preceding claims, characterized in that a drying (140) of a component (20) produced from the ready-mix causes a shrinkage which is in particular at most 10% of the original size or less, preferably 5% or less, more preferably 3% or less, and / or. wherein the shrinkage is similar to the swelling according to the preceding claim, so that the component produced from the ready-mixture has approximately the same material volume as the polymer preparation provided in the ready-mixture, and volume or length changes throughout the production process are less than at most 10% or less based on the material volume, preferably 5% or less, more preferably 3% or less. Ready-mixture (30, 30A, 32, 120) according to one of the preceding claims, the polymer preparation further comprising an organic or inorganic additive. Ready-mixture (30, 30A, 32, 120) according to one of the preceding claims, the polymer substrate (102) comprising polypropylene, polyethersulfone or polyvinylidene fluoride, or a mixture thereof, and / or the diluent (104) comprising soybean oil, castor oil, carnauba wax, s-caprolactam, or a mixture thereof.Ready-mixture (30, 30A, 32, 120) according to one of the preceding claims, comprising the polymer preparation. - polypropylene as polymer substrate (102) in a mass fraction of at least 20 m%, preferably at least 35 m%, more preferably at least 50 m%, and / or up to 40 m%, preferably up to 55 m%, more preferably up to 65 m%, and / or - polyethersulfone as polymer substrate (102) in a mass fraction of at least 10 m%, preferably at least 20 m%, more preferably at least 30 m%, and / or up to 25 m%, preferably up to 35 m%, more preferably up to 45 m%, and / or - polyvinylidene fluoride as polymer substrate (102) in a mass fraction of at least 15 m%, preferably at least 25 m%, more preferably at least 35 m%, and / or up to 30 m%, preferably up to 40 m%, more preferably up to 50 m%, and / or - a mixture of soybean oil with castor oil as diluent (104) in a mass fraction of at least 50 m%, preferably at least 65 m%, more preferably at least 80 m%, and / or up to 85 m%, preferably up to 70 m%, more preferably up to 55 m%, and / or - Carnauba wax as diluent (104) in a mass fraction of at least 50 m%, preferably at least 65 m%, more preferably at least 80 m%, and / or up to 85 m%, preferably up to 70 m%, more preferably up to 55 m%, and / or - c-Caprolactam as diluent (104) in a mass fraction of at least 65 m%, preferably at least 80 m%, more preferably at least 90 m%, and / or up to 95 m%, preferably up to 85 m%, more preferably up to 75 m%. Providing the finished mixture (30, 30A, 32, 120) according to any one of the preceding claims in one of the following forms: as granules (32), powder, flakes, filament, melt cartridge, a cartridge, or for use in a drum melter. Method (100) for producing an easily handleable ready-mix (30, 30A, 32, 120) of a polymer preparation, in particular according to one of the preceding claims, comprising the steps Mixing a polymer substrate (102) with a diluent (104) to provide a polymer-diluent mixture (105), Heating (106) the polymer-diluent mixture to a temperature above the melting temperature of the diluent, Allowing (107) the polymer-diluent mixture to dissolve to provide a homogeneously dissolved polymer preparation (110), Cooling (108) the polymer preparation below a solidification temperature, portioning (115) the solidified polymer preparation, for example by granulation. Method (100) for producing a component (20) from a ready-mixed mixture (30, 30A, 32, 120) comprising the steps Providing (125) the ready-mixed mixture, in particular according to one of the preceding claims, Heating (130) at least a portion of the finished mixture to a temperature above the melting temperature of the diluent and / or the finished mixture and thus providing a homogeneously dissolved polymer preparation, construction (135) of the component, in particular by means of extraction of the homogeneously dissolved polymer preparation, in particular in a monolithic construction, further in particular by means of additive manufacturing. A method (100) for production according to the preceding claim, characterized in that during the construction of the component (20) until its completion, a foreign substance-induced change in volume or length of at most 10% of the original size, preferably of at most 5% or less, further preferably of 3% or less, is effected. Discontinuous method (100) for producing a component (20) from a finished mixture (30, 30A, 32, 120), comprising the steps Providing (125) a first portion of the finished mixture, in particular according to one of claims 1 to 11, heating (130) the first portion of the finished mixture to a temperature above the melting temperature of the diluent and / or the finished mixture and thus providing a first closed amount of homogeneously dissolved polymer preparation, Construction (135) of a first region of the component with the first closed amount of homogeneously dissolved polymer preparation when the first portion of the ready-mixture has been consumed or during the consumption of the first portion of the ready-mixture, provision (145) of a further portion of the same ready-mixture or a further portion of a further ready-mixture, in particular according to one of claims 1 to 11, Heating (150) the further portion to the temperature above the melting temperature of the diluent and / or the finished mixture and thus providing a second closed amount of homogeneously dissolved polymer preparation, Construction (155) of a second region of the component with the second closed amount of homogeneously dissolved polymer preparation. Discontinuous process (100) according to the preceding claim, which is carried out by extraction of the homogeneously dissolved polymer preparation, and / or in a monolithic construction, and / or wherein the discontinuous process is designed as an injection molding process, 3D printing, melt-on-demand, or a combination of the aforementioned. A system (1) for producing components (20) from a ready-mixed mixture (30, 30A, 32, 120), in particular according to one of the preceding claims and / or using one of the preceding processes (100), comprising at least one ready-mixed mixture reservoir (12) for easily providing the solid ready-mixed mixture (30, 30A, 32, 120), a heating device (17, 17a) for heating at least a portion of the ready-mixed mixture above the melting temperature of the diluent, and a placement device (18), such as an extruder, for constructing the component (20).Plant (1) according to the preceding claim, wherein the ready-mixed mixture (30, 30A, 32, 120) is provided as granules (32) and / or as a melting cartridge, and / or wherein the at least one ready-mixed mixture reservoir (12) is provided as a barrel, and wherein the heating device (17, 17a) is adapted to be immersed in the ready-mixed mixture reservoir as a barrel melter, or wherein the ready-mixed mixture is provided as a filament and the heating device is provided as a continuous melter. Plant (1) according to one of claims 16 or 17, further comprising a second ready-mixed mixture reservoir (13) for providing a second ready-mixed mixture (30A) that is different from the first ready-mixed mixture (30). Plant (1) according to one of claims 16 to 18, wherein the plant is designed to carry out a discontinuous process such as injection molding, 3D printing, melt-on-demand or a combination of the above.Component (20) produced from the ready-mixture (30, 30A, 32, 120) and / or according to a method (100) and / or with the plant (1) according to one of the preceding claims.

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