EP2346928A1

EP2346928A1 - Lyzable molded parts

Info

Publication number: EP2346928A1
Application number: EP08874924A
Authority: EP
Inventors: Klaus Rennebeck; Bernd Hildenbrand
Original assignee: LEONARDIS-STIFTUNG; Prager Robert; LEONARDIS STIFTUNG
Current assignee: LEONARDIS-STIFTUNG; Prager Robert; LEONARDIS STIFTUNG
Priority date: 2008-10-03
Filing date: 2008-10-03
Publication date: 2011-07-27
Also published as: US20110177316A1; WO2010037353A1

Abstract

The invention relates to a method for producing a biodegradable molded part, comprising: providing a binding agent which contains a lyzable biopolymer; forming a molded part from the binding agent, wherein the time stability of the molded part to biological lysis is set by at least one of the following measures: adding a pulverized inorganic solid matter in a proportion of 5% to 85% of the mass of the binding agent before forming the molded part; thawing at least one of the surfaces of the molded part using a chemical or biological method such that the surface has a structuring in the range between 1 nm and 10 µm. The invention further relates to an accordingly produced molded part.

Description

Lysable moldings

The invention relates to a process for the preparation of biodegradable ren molded parts such as films and fibers and such moldings.

For the purposes of the present invention, the term "biodegradable" means any degradation process by microorganisms or their enzymes according to which the molecular structure present in the moldings is split. An example of such a biodegradation process is the (human or animal) digestion. In particular, biological lysis is also subject to this term.

Since their first chemical synthesis, polymers have become rapidly widespread in industrial products of various kinds. The development of new polymers has resulted in versatile plastics of a wide variety of properties such as temperature resistance, moldability, thermal conductivity and the like.

Recently, the focus of new developments has been increasingly focused on so-called "biopolymers", which are firstly understood from renewable raw materials synthesized polymers, and secondly biodegradable plastics (plastics). There is an intersection between the two types of biopolymers, ie polymers based on naturally renewable raw materials, which are also biodegradable. All of these types of biopolymers are currently the subject of intense research to provide environmentally friendly raw materials for industrial products. Examples of such inserts are, in particular, packaging films or fibers for use in textile production.

The term "biopolymer" as used hereinafter to describe embodiments of the invention is based on the first of the definitions mentioned and thus describes a polymer synthesized from renewable raw materials. For different applications of biopolymers different stability periods are desired, ie the resistance requirements that such a polymer opposes to its microbial or enzymatic degradation differ depending on the nature and use of the molded product made therefrom.

The invention has for its object to meet these needs and to provide a method for producing biodegradable moldings, with which the stability period of such moldings can be adjusted to a desired range. Furthermore, it is the object of the invention to provide a corresponding molding.

The object is achieved by a method according to claim 1 and a polymer molding according to claim. Preferred embodiments are specified in the subclaims.

The process for producing a biodegradable molding comprises the following steps:

Providing a binder containing a lysable biopolymer;

Forming a molding from the binder; wherein the temporal stability of the molded article to biological lysis is adjusted by at least one of the following: a) adding a powdered inorganic solid in a proportion of between 5% and 85% of the weight of the binder prior to forming the molded article; b) roughening at least one of the surfaces of the molding by means of a chemical or biological process, so that the surface has a structuring in the range between 1 nm and 1 Oμm.

The invention thus relates to the control of biodegradability in time dimension. Products made with embodiments of the method according to the invention can thus be adapted to the specific needs of the intended use in terms of their durability or lifetime.

In one embodiment, the method aims to structure the surface of a molded part containing a lysable biopolymer in a targeted manner in order to set the desired degradability with regard to the duration of the degradation process. Here comes the so-called "lotus effect" used by the present method for the purpose of controlled biodegradation. The term "lotus effect" describes the fact that, in the case of a microstructured or nano-structured surface, this has a low wettability. Water and other 5 liquids, which settle on the surface, do not stay there or only to a small extent adhere and roll off instead.

The lotus effect can be achieved on the one hand by adding a pulverized solid, in particular an inorganic solid, to the binder. The particle size

10 of the powdered solid is approximately in the range of a few nanometers to a few micrometers. In particular, the particle size may be in the range of about 1 nm to about 10 microns. In this context, the term "particle size" is intended to mean the average particle size of the powdered solid, such as e.g. Bone marrow, hydroxyapatite, Diatomeen®, feather dust (powdered bird feathers), kieselguhr and / or alumina,

15. be understood. In the case of nanoparticles, the average particle size is less than 1 μm, more preferably less than 100 nm. The micro- or nanoparticles in the binder cause a structuring of the surface of the molded part to be produced, so that the lotus effect described above is formed. In general, the smaller the powdered solid particles contained therein, the greater the density of the molded article. A greater density acts to reduce the lysability of the molding, i. the duration increases until complete dissolution of the molding. This effect occurs in addition to the lotus effect mentioned.

Preferably, the powders for admixing with the binder are in a highly pure form. The pulverized solid is therefore preferably almost free of impurities (purity> 99.9%) or foreign substances.

Another possibility for the targeted formation of the lotus effect on a molded part is that the finished molding surface is structured by means of a physical or chemical treatment method. Among the variety of surface processing methods, those which make it possible to obtain a structure having the desired fine surface roughness on the surface of the binder material are suitable. For this purpose, for example, a treatment of the surface with UV radiation or isotope beams as physical surface treatment methods in question. Also one Pyrolytic coating of the molding surfaces is a suitable method to apply the micro-scale or nano-scale surface structures.

A pyrolytic coating generally occurs at a temperature range between about 500 ° C and about 900 ° C. The hot pulverized material with particles in the size range of a few nanometers to a few micrometers can be sprayed on the molded part, which is also in the heated state, for example.

In contrast to the two mentioned surface treatment methods of irradiation with UV light or ion beams, the pyrolytic coating is thus a method in which not the existing surface is roughened, but instead a further surface layer is applied to the existing surface. In addition to the pyrolytic coating, of course, other suitable coating methods can be used.

Pyrolysis may also be used as an isolated process (i.e., not in the context of a coating) to pattern the surface. In the process, depressions are burned into the molded part as a result of the heating. In the case of thin films or hollow fibers, pyrolyzing, i. the formation of holes instead of mere depressions possible.

Finally, a surface treatment with tannic acids, aldehydes, salts, alcohols and oils, as well as talc, waxes and carbon blacks can be done.

Upon irradiation of the molded article with UV light, the strength and duration of the treatment are dependent on the composition of the binder, as well as the desired structuring. In general, however, it can be stated that for structuring a molded part to form a surface with the desired degree of roughness, irradiation of the molded article with UV rays having a frequency of about 250 to about 350 nm, in particular about 280 to 320 nm, over a period of time from about 30 s. until about 30 minutes is required.

As already mentioned, instead of the irradiation with or in addition to UV light, irradiation with ion beams may also be used for structuring the surface of the molded part be used. For example, radon can be used as ion sources. The duration of the irradiation may be selected, for example, between a few seconds and about 30 minutes. In particular, a period of about 20 seconds to about 10 minutes is suitable for the formation of the structured surface.

In addition to the aforementioned measures for the formation of a lotus effect, the stability to degradation such as lysing or digestion can also be influenced by the composition of the binder. In particular, the proportion of products from the so-called "citric acid cycle" and the Zellatmungskette in the binder for setting the lysing capacity of importance. These include, for example, the compounds NADH, ATP, ADP ₅ succinic acid, aspartic acid, FAD ₅ citric acid, butyric acid and lactic acid. The better the proportions of these substances in the binder are coordinated, the more targeted is the biodegradation.

Other binder components which may influence the degree of hydrophobicity or hydrophilicity and / or the degree of lipophilicity or lipohily are: silicon compounds, in particular soapstone and talc, minerals, silicone oil, lanolin (wool oil), uric acid, oxalic acid, bone china , Feather dust, tartaric acid, shellac, egg white, kieselguhr, clay, cysteine, resilin.

The composition of the binder also has an influence on the permeability of the molded part for oxygen. If the binder does not contain starch, the molding is substantially impermeable to oxygen. If amino acids are present in the binder, they also contribute to the impermeability to oxygen. If the binder contains a starch polymer and an amino acid polymer in non-homogeneous mixture, the resulting molded article becomes selectively permeable. Depending on where in the molding the starch-containing regions are, the molding is oxygen permeable at these sites, while it is impermeable to oxygen at those sites containing amino acids (e.g., collagens).

The molded part can be completely or partially lysierbar. For example, it is possible to form a surface by the described structuring by means of the methods indicated above in such a way that the wetting ability against the smooth surface is reduced. Thus, water, working fluids or other fluids may be used optionally be completely anhydrous, relatively less attack on this surface, which is why the degradation process of the biodegradable molding is delayed from this side. The dissolution process of the biodegradable molding then progresses asymmetrically, more from the smooth side and less from the structured side.

As regards suitable materials for the binder, it may contain one or more of the following: biopolymers such as blood, components of blood, proteins, peptides, cellulose, starch, cutin, acetates, glycerines, alcoholates, resins, waxes, agar-agar, Collagens, talc, fats, cysteines, gelatins, bone gums, bone oil, trans oil, cartilage gels, skin gums, rabbit gums, fish gums, ureas, caseins, polymers, in particular polyvinyl alcohol, polyethylenes, polypropylene, polyvinyl esters, polyvinyl acetate, polyamines, polyacrylics, polyesters, polyamides, polyimides , Polysulfones, polysulfides, polystyrenes, cellulose copolymers. In this case, the binder can be added in solid form, provided that it is meltable., Or in powder form, if it is then with a suitable meltable binder, particularly preferably with a resin, wax, especially wool wax (lanolin), linseed oil, hemp oil, linseed oil, terpene , Turpentine oil, sol gel, fresh egg, water glass, CS2, carbon sulfur, methyl chloride, methyl, silicone oil, urea, polyvinyl alcohol and / or a suitable solvent. In addition, depending on the processing method for molding, the binder may contain or include anionic or cationic solid slips.

If the binder is to have elastic properties but at the same time be biodegradable, then Resilin is suitable as a binder component.

In particular, the binder should be i. the binder for carrying out the process will be in a state which is sufficiently liquid, i. casting, spraying, extruding or spinning is. If the lysability is adjusted by means of a pulverulent solid, then the powdered solid is admixed to the binder before shaping or else applied by means of a coating method, for example by means of pyrolitic coating. Preferably, the binder has a gelling ability of about 160 bloom prior to processing.

In conjunction with one of the aforementioned binders may also be a sol gel, for example in the form of salt compounds with which the nanoparticles are mixed or which per se contains the nanoparticles.

The pulverized solid preferably contains at least one of the following constituents: oxides, silicic acid, zeolites, silicon, silicon compounds, calcined bone ash, hydroxyapatite, metals, silanes, magnetite, hematite, iron pentacarbonyl, lithium chloride, anatase, rutile, zinc chloride, lithium, zinc, manganese, Selenium, rare earths, perovskites. If fusible binders are used again, the pulverized solid preferably contains SiO ₂ , TiO ₂ , ZrO ₂ and / or Al ₂ O ₃ . In general, the pulverized solids can be both organic and inorganic in nature. Inorganic solids may also be ionic conductors such as zirconium oxides. In addition, it is also possible to use biological proton conductors which are sulfonated, fluorinated or phosphorized or represent a combination of these substances.

The shaping step may include, for example, spraying, casting, extruding or spinning. In this way, the lysable molding can be formed as a film, fiber or hollow fiber. The moldings can be produced in several layers or single layers. The multi-layeredness, in particular two-layeredness, is particularly suitable when asymmetric lysability of the molded article is desired. Methods for forming such two- or multi-layer moldings are described for example in DE 10 2005 056 491. The methods of spinning, extrusion, casting or spraying disclosed therein for multilayer moldings are applicable to the embodiments of the present invention.

If a two-layer or multi-layer is desired, the respective binder compositions can be processed both in one operation and in two or more successive operations. By "process" is meant here the step of forming the molded part. If two or more operations are selected, they are carried out in chronological succession according to an embodiment of the invention. It is important to ensure that the time sequence of the operations is sufficiently fast, so that the first processed mass forms no or only a minimal skin layer on the surface. There is no casting or coating in this case.

A lysable or partially lysable molding according to an embodiment of the The invention comprises a binder containing a lysable biopolymer wherein the binder contains at least one of the following components: plant collagens, animal collagens, gelatin, acids of the citric acid cycle, reaction products of the cellular respiratory chain, resilin. The proportion of products from the citric acid cycle as well as the cell respiration chain in the binder is of importance for the adjustment of the lysing ability. These include the compounds NADH, ATP, ADP, succinic acid, aspartic acid, FAD, citric acid, lacquer such as shellac (Lacca in tabulis). The more differentiated the proportion of these substances in the binder, the more targeted is the biodegradation.

In this way, on the one hand, the biological and / or chemical degradability of the molded part is ensured. In this way it is ensured that the molded part has a finite life. On the other hand, the molded article has properties that can reduce the degradability or lysing ability, so that the degradation time i. Degradation time extended. This retardation of biological or chemical lysis leads

At least one of the surfaces of the molded part may have a structuring in the micro or nano range. This structuring can, as already described, be carried out by processing methods such as photochemical structuring, UV or ion irradiation, by addition of microparticles or nanoparticles into the binder mass of the molded part to be formed. In addition, there is the possibility that the molded part is a woven fabric knitted, woven, knitted or otherwise formed from micro or nano hollow fibers. It may also be an accumulation of loose fibers which have been removed by means of a binder, e.g. of an adhesive, to be held together.

Within the scope of the embodiments of the invention, the term "hollow micro fibers" or "nano hollow fibers" is to be understood as meaning fibers whose equivalent outside diameter is between one and several micrometers or nanometers. Such fibers may have wall thicknesses between about 8 and 800 nm, in particular between 30 and 380 nm, and between 50 nm and 180 nm according to some embodiments. The length of the fibers may be about 30 mm to about 300 mm. Of course, depending on the application, longer or shorter fibers can be produced and used within the scope of the invention. Thus, corresponding textile staple fibers can be produced up to a length of about 20,000 m. The micro or nano hollow fibers, which are processed into a woven or knitted fabric, in turn, a uniform wall thickness over the Have fiber length away.

Such fine hollow fibers can be made by spinning out the binder containing the degradable or lysable biopolymer. In order to spin out such fine structures, the use of an atomic force microscope is required. Such microscopes are known in the art, so their operation will not be discussed in detail here. Inside the spinneret, which is used for spinning out the fine hollow fibers, there is a Lumenbildner. This is made of a metal or a metal alloy. In particular, materials such as tantalum, tungsten, titanium or alloys containing these metals are useful as the starting material for the lumen builder. This may for example be made in a spinneret made of ceramic or other suitable material. For hollow fibers in the micron range, the lumen former has a diameter of, for example, 6 nm to 20 μm. The biologically lysable hollow fibers spun out of such a spinneret already have their final contour. Stretching the fiber after the spun-off process is usually unnecessary.

As already mentioned, in addition to spinning, extrusion is also a suitable shaping process for producing a molded part according to an embodiment of the invention. As a raw material for the extrusion process (as well as the other mentioned molding methods), the binder may be provided as a melt. Following the molding process, e.g. extruding, the molding can be solidified and cooled by means of a coolant in the form of an anhydrous lost liquid. In this context, the term "lost" means that the liquid penetrates into the wall of the molding to a certain depth in the course of the cooling process, mixes with the binder and thus becomes part of the wall of the molding. It is thus a so-called reaction coolant. The coolant may also have the lubricity improving properties according to an embodiment of the invention. As an example of such a reaction lubricant with sliding lubrication is silicone oil. The silicone oil acts cohesively, but without affecting the lysing ability. In addition, the strength of the wall into which the lubricating coolant is added during processing is increased.

As a result of the cooling process after the shaping process, a structuring of the surface of the formed molding can also be carried out. It is true that ever the faster the cooling process takes place, the more pronounced the structural pattern of the surface becomes, ie the deeper the structure becomes in the surface. The structuring, which lies in a depth range of a few nanometers, can be produced, for example, using a transmission microscope.

In order to extrude a binder (which optionally contains nanoparticles) from the materials mentioned above, cooling during the extrusion process can be used. This cooling can be downstream of the extruder, for example, as a cooling bath. In addition, additionally or alternatively, a cooling fan may be provided around the extruder, or else one or more cooling channels incorporated in the cylinder. In this way, hydrolysis products of animal cell tissues from poultry, game, fish or other domestic or farm animals can be subjected to the shaping process. The technically more complex and cost-intensive injection molding can thus be circumvented.

With the above methods, continuous extruding, that is, continuous spinning, i. a molding without deduction of the extrusion or spinning process possible. This means that fibers of any length can be produced. These fibers are then available for further processing by conventional fiber processing techniques. In this way, also woven or knitted fabrics can be made from the lysable fibers. Common to both shaping method is the formation of a hydraulically equivalent diameter of the hollow profile of the fibers.

If nanoparticles in solid form are used for the pattern formation of one or more of the surfaces of the molding, this additionally has the advantage that the binder is additionally given strength and stability. This effect is especially at

Moldings with low wall thickness low, since their dimensional stability compared to

Moldings with the same binder, but without Nanofeststoffteilchen, can be increased in this way. In addition, the powdered solid may also have the properties of an electrolyte within the molding, if a suitable material for the

Solid is selected. In this context, for example, titanate can be used.

According to one embodiment of the invention, the binder may also be silicon as well Contain silicon compounds. Thus, according to one embodiment, silanes (monosilane or longer-chain silanes) can be introduced into the biopolymer binder in a sealed manner. Subsequently, the molding is formed in one of the manners described above. By heating during molding, the silanes react with the oxygen in the air to produce pure silicon and silica. This silica in turn affects the lysability of the molded part produced in such a way that the lysability is adjustable with respect to water with increasing proportion of silica. Other possible reaction products in the decomposition of the silanes are hydrogen and diatomaceous earth, which accelerate the degradation or lysis of the finished molding.

To increase the elasticity of the finished molded part, the binder may contain, for example, resiliency and / or collagens. The elastic properties of a molded part produced from said materials are enhanced when glycerine, sugar and / or starch are additionally added to the binder.

Hollow fibers made from binders containing collagen may, depending on the proportion of collagen in the binder, be impermeable to oxygen but permeable to nitrogen. For this reason, they can be used for air separation or separation of the constituents of air. The fibers can be used both in the sintered and in the unsintered state. A similar effect can also be achieved if a hollow fiber of lysable biopolymers contains zirconia solid nanoparticles. The zirconia in the binder causes oxygen ions to pass through the walls of the molding. The sintered fibers with a ceramic or metal component can then be used as catalysts, for photovoltaic elements or as a molecular sieve, recuperator and regenerator, as a thermogenerator and as an anion and cation exchanger.

The moldings may be, for example, films with a thickness of one atomic layer to a few atomic layers up to 1 mm. For certain applications, it makes sense if the film thickness is between 1 μm and 300 μm. In addition, the moldings can be made as Hohlprofϊle, eg tubes or hollow fibers. The hollow fibers may be textile fibers having an inner diameter of 80 nm to 30 microns. The wall thickness of the hollow fiber may correspond to the film thickness, for example. Of course, the moldings may also be solid fibers and rods without internal cavity. The moldings according to the embodiments of the invention can be used for a variety of purposes. The fact that from a lysable biopolymer used as a binder, a molded article whose lysability can be adapted to the particular use, makes it possible to produce numerous disposable articles of biodegradable materials.

A potential area of use of such moldings are disposable cosmetics or toiletries. Here, the lysing is adjusted so that the moldings remain stable until their use, but in the wastewater within a very short period, namely about 10 minutes to about a week, dissolve or degrade. One embodiment of the invention accordingly relates to a cotton swab whose rod body is made of a lysable biopolymer binder, wherein the surface of the rod body is structured so that the lysis does not occur immediately after contact with water.

Another embodiment relates to a textile fabric or, more generally, a textile structure of textile fibers or hollow fibers formed from a binder containing a lysable biopolymer. The lysable biopolymer may contain components of natural collagens as well as residues from process steps of various hydrolysis reactions. These incineration residues can form, as ashes, the pulverized solid which is introduced into the binder in order to influence the lysability.

The textile structures or fabrics may, according to embodiments of the invention, be a facial tissue or diaper for children or in the case of adult incontinence. In particular, in the case of the diaper, it is important that the binder has a certain elasticity, which is why the already mentioned Resilin or collagens may be included.

According to other embodiments, the use as a technical textile is possible. These may be in particular redox and lithium ion batteries as well as anion and cation exchangers, recuperators and regenerators. The fibers or hollow fibers of which such textiles are made are preferably fired after sintering or extrusion. If, as already described, the surfaces of the molded part are impermeable to oxygen by the use of collagens and omitting starch polymers, or only partially permeable to oxygen, the molded part can also be used as corrosion protection, for example for motor vehicles in the form of underbody protection. For this purpose, the molding is formed as a film of a biopolymer and with about 40 to 70% Silicea, in particular about 50 to 65% Silicea. The advantage of a corrosion protection from a collagen-containing molding is inter alia that it has a smoke-reducing effect, which is particularly favorable in connection with motor vehicles. Moreover, in the molding process, as already mentioned, an anhydrous liquid can be used as a coolant or as a combined coolant / lubricant for the molding process, eg, extrusion. The cooling or cooling / lubricating agent (eg silicone oil) is added to the melt of the binder before the screw extruder is charged, but without mixing the two constituents. Subsequently, the shaping process takes place with subsequent cooling of the extruded melt in an immersion bath, for example at room temperature. However, the coolant or coolant / lubricant may also be the filling of the dip bath.

As an alternative molding process, a vacuum press can also be used. This results in films that can then optionally be fired or sintered.

With regard to the extrusion process, it is also possible to produce granules based on the lysable biopolymers.

Embodiments of the invention will be described below with reference to the drawings, which are to be understood as non-limiting examples. In the drawings show:

Figure 1 shows a first molded part according to an embodiment of the invention, which is designed as a hollow fiber;

Figure 2 shows a second molded part according to another embodiment of the invention, which is formed as a film;

Figure 3 shows a third molding according to another embodiment of the invention, which is designed as a cotton swab; and

Figure 4 shows a method according to an embodiment of the invention, in which the molded part is formed as a thermoforming fiber. FIG. 1 shows a first embodiment of the invention. The embodiment is a molded part 1, which is designed here as a hollow fiber. By way of example, this hollow fiber may be a hollow micro-fiber, meaning that its outer diameter is smaller than 1 mm.

The hollow fiber is here single-layered, i. that the entire wall is substantially homogeneous in composition. Of course, it is also possible to form the hollow fiber in two or more layers, so that layers of different composition are present in the thickness direction of the wall. In other words, the hollow fiber is then inhomogeneous in the thickness direction of the wall.

The hollow fiber has an outer surface Ia and an inner surface Ib. One or both of the surfaces 1a, 1b may include a structuring such that the lysability of the binder, which forms the basic constituent of the hollow fiber, is limited. In other words, the duration is delayed until the dismantling of the molded part 1 on the corresponding wall side. The hollow fiber can be produced by an extrusion process or a spinning process.

The hollow fiber shown in Figure 1 can be further processed into textile structures, such as fabrics or knitted fabrics. Such textile structures can be used in particular as diapers or facial tissues.

FIG. 2 shows a further embodiment of the invention. The molded part 1 'of this embodiment is a film, which is also shown here in one layer. Since the foil, unlike the hollow fiber of the first embodiment, is not a hollow profile, this embodiment has only one outer surface 1 a. This surface may also have a structuring.

The embodiment of Figure 2 can be further processed in many ways, for example as a deep-drawing cylinder, as a tube, catheter or hollow fiber. For this purpose, for example, the already mentioned deep-drawing process can be used, which will be explained in more detail below with reference to Figure 4. The thermoforming process is a thermo-vacuum process, by means of which at first a one-sided closed Pipe or tube or a sealed fiber can be produced, which can then be opened in a further process step (eg by cutting).

A production of the lysable film shown in FIG. 2 is possible, for example, by an extrusion process.

Finally, FIG. 3 shows a third embodiment of the invention. In this case, the molded body 1 "is formed as a cotton swab, which looks similar from its outline to a conventional cotton swab.

The cotton swab consists in the embodiment shown of a stem body 2 and two bulky ends 3, which serve for cleaning. Handle body 2 and ends 3 may be made of the same or different materials. The stem body 2 can be formed in an extrusion process from a screw extruder. The bulky ends are then applied in a separate process.

The cotton swab, which is made of a binder of the aforementioned materials, can be adjusted in terms of its lysability so that it is completely degraded in the wastewater after about 10 minutes to about a week.

As an example of a composition of a binder for a cotton swab, in which the stem body 2 and ends 3 are made of the same material, the following values can be given: 50% zirconium dioxide and 50% gelatin or 60% zirconium dioxide and 40% gelatin or 60% Silicea and 40% Gelatin. The binder can be used as granules or fractions for melting e.g. be provided in the extruder.

The melt is then processed, for example, in the extruder to form a rod, which then forms the stem body 2 of the cotton swab. The thickness of the rod or tube may be about 3 to 6 mm, especially about 4 to 5 mm, as needed. After the extrusion process, the rod or tube is cooled in an immersion bath, which preferably consists of a completely anhydrous liquid coolant / lubricant, for example silicone oil. The KühWSchmiermittel in the immersion bath is heated to about 30 ⁰ C to about 60 ° C, so that a cooling and solidification of the still-hot extruded rods or tubes. Due to the lubricant property of the cooling liquid is a Sticking the extruded rods prevented. In addition, the coolant / lubricant also has the effect that odor emissions of the binder can be avoided.

The ends 3 of the cotton swab are formed with the stem body 2 of the same material from the above materials. In contrast to the production of the rods that will

Binder material provided here as a textile dust particles, which is a waste product of

Can be chopsticks production. The dust particles can be compressed by means of compressed air

Volume be puffed up. Subsequently, the cotton thus produced - optionally with the use of a adhesion-increasing agent such. a small amount of water - mounted on the stem body.

FIG. 4 shows an exemplary manufacturing process for a fiber or a tube or a rod according to an embodiment of the invention. A binder containing a lysable biopolymer and optionally a pulverized solid is applied or deposited as a film 4 on a perforated block 5. Then there is a heating of the film 4, for example by infrared radiation, which is indicated here by wavy lines 6. The film is heated until it is flowable or drawable.

The perforated block 5 has openings 5 'which extend through its entire thickness. In FIG. 4, for reasons of simplicity of illustration, only one opening is shown

5 ', but it will be apparent to those skilled in the art that multiple apertures 5' may be present which extend in parallel through the thickness of the block 5. A negative pressure is created on the lower side of the perforated block 5 opposite the film 4, so that the flowable heated binder of the film 4 is drawn through the opening as shown by the arrows. At the lower end of the opening 5 'exits a tube, which can be cooled and solidified in the manner already described.

A molded part formed by an embodiment of the method according to the invention can be lysed starting from one of its surfaces or starting from several surfaces. If the molded part is, for example, a hollow profile, the lysis can be carried out starting from the outside inwards or vice versa, according to a case. According to another case, the lysis may proceed uniformly from the inner and the outer surface of the hollow profile. Finally, it is also possible that lysis begins on both surfaces, but with different Speeds from the outer surface and the inner surface progresses.

The asymmetrical course of the lysis of a molded part according to one embodiment of the invention can either be deliberately brought about by forming the different surfaces with different materials for binders or the pulverized solid contained therein, with different grain sizes of the solid and / or with different surface structuring. Here, the term "different surface structuring" may mean that the structures of the surfaces differ in their depth (i.e., the degree of roughness), the density of the grain, and / or the grain size. In this way, a different lotus effect ensures the asymmetry. Of course, the different lysis course may also be due to the environmental conditions (e.g., humidity) to which the various surfaces are exposed.

^~ It is to be noted that the above-mentioned embodiments of the invention are given only as non-limiting examples.

Claims

claims

A process for producing a biodegradable molded article, comprising:

Providing a binder containing a lysable biopolymer; Forming a molding from the binder; wherein the temporal stability of the molded article to biological lysis is adjusted by at least one of the following: a) adding a powdered inorganic solid in a proportion of between 5% and 85% of the weight of the binder prior to forming the molded article; b) thawing at least one of the surfaces of the molded part by means of a chemical or biological process, so that the surface has a structuring in the range between 1 nm and 10 μm.

2. The method according to claim 1, characterized in that the pulverized inorganic solid contains nanoparticles.

3. The method according to claim 1, characterized in that the pulverized solid contains at least one of the following constituents: oxides, silicic acid, zeolites, silicon, silicon compounds, calcined bone ash, hydroxyapatite, metals, silanes, magnetite, hematite, iron pentacarbonyl, lithium chloride, anatase, Rutile, zinc chloride, lithium, zinc, manganese, selenium.

4. The method according to claim 3, characterized in that the pulverized solid contains one or more oxides of the following group: vanadium oxide, titanium oxide, tungsten oxide, cobalt oxide, iron oxide.

5. The method according to claim 1, characterized in that the binder contains at least one of the following components: plant collagens, animal collagens, gelatin, Resilin.

6. The method according to claim 1, characterized in that the binder contains acids of the citric acid cycle and / or reaction products of the Zeilatmungszyklus.

7. The method according to claim 1, characterized in that the molded part as a film or fiber, in particular as a hollow fiber, is formed.

8. The method according to claim 7, characterized in that the formation of the molding takes place in one of the following processes: casting a film, blowing a film, extrusion of a film, extrusion of a hollow fiber, deep drawing a film, winding a hollow fiber of a film, deep drawing a fiber from a foil.

9. The method according to claim 8, characterized in that the thawing of the at least one surface of the molding is carried out as a coating thereof with a nanoparticle-containing cover layer.

10. The method according to claim 9, characterized in that the coating of the molding is carried out by means of pyrolysis.

11. The method according to claim 1, characterized in that the thawing of the at least one surface of the molding as an irradiation of the molding with UV rays with a

Frequency of 250 to 350 nm over a period of 30 seconds to 30 minutes.

12. The method according to claim 1, characterized in that the thawing of the at least one surface of the molding takes place as an irradiation of the molding with isotope radiation with an intensity of over a period of 5 s to 20 min.

A lysable molding comprising a binder containing a lysable biopolymer, characterized in that the binder contains at least one of the following: plant collagens, animal collagens, gelatin, citric acid cycle acids, cell respiratory chain reaction products, resilin, at least one of Surfaces of the molding has a structuring in the micro or nano range.

14. A lysable molding according to claim 13, characterized in that the molding contains an inorganic solid in a proportion between 5% and 85% of the mass of the binder, wherein the inorganic solid is in the form of nanoparticles.

15. Lysierbares molding according to claim 13, characterized in that the molded part is formed as a hollow fiber having an inner diameter of 80 nm to 30 microns.

16. A lysable molding according to claim 13, characterized in that the molding is formed as a film having a thickness of one atomic layer to 1 mm.

17. Lysierbares molding according to claim 13, characterized in that the molding is designed as a cotton swab.

18. Lysierbares molding according to claim 13, characterized in that the molded part is formed as a non-woven fabric.

19. A lysable molding according to claim 13, characterized in that differ at least two of the surfaces (Ia, Ib, l'a) of the molding with respect to their structuring.

20. A lysable molding according to claim 13, characterized in that differ at least two of the surfaces (Ia, Ib ₅ , l'a) of the molding with respect to the composition of the binder.