WO2004033202A1

WO2004033202A1 - Blown multi-layered film with a lotus-effect

Info

Publication number: WO2004033202A1
Application number: PCT/EP2003/008686
Authority: WO
Inventors: Markus Oles; Edwin Nun; Gernot Dambacher
Original assignee: Creavis Gesellschaft Für Technologie Und Innovation Mbh
Priority date: 2002-09-24
Filing date: 2003-08-06
Publication date: 2004-04-22
Also published as: DE10244490A1; AU2003260372A1

Abstract

The invention relates to multi-layered films with surfaces, which have automatic-cleaning properties and also to a simple method for producing said films having automatic-cleaning surfaces. The inventive method is very simple and can use existing tools. Normally, multi-layered films are produced according to film blowing methods. The inventive method uses said method by applying microparticles to the blown layer which has not yet been solidified. The microparticles are fixed thereon after the layer has solidified. The microparticles are also applied to layers which are to be blown again and provided with a layer and multilayer films are obtained, comprising a plurality of microparticle layers. Material from the automatic-cleaning surface is removed by effervescence and new structural formers are later provided by the lower lying layers of microparticles, such that the inventive films have visibly longer automatic-cleaning effects than films which have microparticles exclusively on the surface.

Description

Blown multilayer films with lotus effect

The invention relates to blown multilayer films with a lotus effect and to a process for their production.

The production of films with self-cleaning properties, that is to say films which are cleaned by moving water, has already been described many times. For the first time, the structure required for the self-cleaning effect (lotus effect) was created by an embossing stamp in a UV-curing lacquer system. Structures such as those described by Schleich and Peters in EP 0 933 388 were used here.

The production of structures for self-cleaning by applying particles to a surface was first described in JP 07-328532. Here, hydrophobic silica fine particles were fixed to a surface with a resin film. Recently, methods have been developed with which it is possible to produce a structured surface formed by particles without the use of fixing agents. For example, the not yet published application DE 102 10667.3 describes the production of web products with self-cleaning properties by means of a calendering process. The application discloses a method by which nanoparticles can be brought into the surfaces of the calendered products. A method for producing surface extrudates with self-cleaning properties has also been developed, which is described in the as yet unpublished application DE 102 10 674.6. As with the method described in DE 102 10 667.4, the method described in this application is also limited to the application of nanoparticles to the outermost layer. The same applies to the shaping processes generally described in DE 102 10 666.5, in which particles are applied to the mold and are transferred to the shaped body through the shaping process.

The surfaces produced by embossing or applying particles with self-cleaning properties had a serious disadvantage because the structures weather off the surface relatively quickly, so that the self-cleaning effect is lost after a short time. It was therefore an object of the present invention to provide a possibility of permanently equipping surfaces with a self-cleaning effect.

Surprisingly, it has been found that it is possible to coat both the outer surface of the film and the intermediate layers of the film with particles when blowing multilayer films. In this way, foils can be obtained which have a self-cleaning effect even after the outer layer of structure-forming particles has been weathered, since new particles are continuously released from the inner foil layers by the weathering and the self-cleaning effect regenerates itself.

The present invention therefore relates to a multilayer film made of thermoplastic with at least one surface which has a surface structure with self-cleaning properties, the surface structure being formed by a firmly anchored layer of microparticles, which is characterized in that the film is composed of several layers of thermoplastic Plastic is formed, a layer of firmly anchored microparticles being present between at least two such layers.

The present invention also relates to a method for producing multilayer films according to one of claims 1 to 11 with at least one surface which has a surface structure with self-cleaning properties, the

Surface structure is formed by a firmly anchored layer of microparticles, which is characterized in that the multilayer films are produced by means of a film blowing process in which several layers of thermoplastic materials are blown into one another, with the production of a layer of

Microparticles between two layers of thermoplastic after

Inflating a first layer of thermoplastic and before the thermoplastic solidifies, microparticles are applied to this layer, which are fixed to the layer after the layer has solidified and then a further layer of thermoplastic is blown into the first layer coated with microparticles and for Production of a surface which has a surface structure with self-cleaning properties, the surface structure being fixed by a anchored layer of microparticles is formed, microparticles are applied to the first blown layer on the outside and / or the last blown layer inside, which are fixed to the respective layer after it has solidified.

The films according to the invention have the advantage that they have the self-cleaning effect for a significantly longer time than films which e.g. were produced by extrusion and which have microparticles only on the surface.

The method according to the invention is relatively simple to carry out since the known apparatuses for the film blowing method can be used.

The invention is described below by way of example, without being restricted to these embodiments.

The multilayer film of thermoplastic material according to the invention with at least one surface which has a surface structure with self-cleaning properties, the surface structure being formed by a layer of microparticles firmly anchored to the surface, is characterized in that the film is formed by several layers of thermoplastic material with at least one further layer of firmly anchored microparticles between at least two such layers.

The surface structure formed by the microparticles with self-cleaning properties preferably has elevations with an average height of 20 nm to 25 μm and an average distance of 20 nm to 25 μm, preferably with an average height of 50 nm to 10 μm and / or an average distance from 50 nm to 10 μm and very particularly preferably with an average height of 50 nm to 4 μm and / or an average distance of 50 nm to 4 μm. The surface extrudates according to the invention very particularly preferably have elevations with an average height of 0.25 to 1 μm and an average distance of 0.25 to 1 μm. In the context of the present invention, the mean distance between the elevations is understood to mean the distance between the highest elevation of one elevation and the next highest elevation. Has an elevation in the form of a Cone is the top of the cone, the highest point of the elevation. If the elevation is a cuboid, the top surface of the cuboid represents the highest elevation of the elevation.

The self-cleaning properties are due to the wetting properties which are described by the contact angle that a drop of water forms with a surface. A contact angle of 0 degrees means complete wetting of the surface. The static contact angle is generally measured using devices in which the contact angle is optically determined. Static contact angles of less than 125 ° are usually measured on smooth hydrophobic surfaces. The present films with self-cleaning surfaces have static contact angles of preferably greater than 130 °, preferably greater than 140 ° and very particularly preferably greater than 145 °. It was also found that a surface only has good self-cleaning properties if it has a difference between the advancing and retreating angles of at most 10 °, which is why surfaces according to the invention preferably have a difference between the advancing and retracting angles of less than 10 °, preferably less than 5 ° and very particularly preferably have less than 4 °. To determine the angle of progression, a drop of water is placed on the surface by means of a cannula and the drops on the surface are enlarged by adding water through the cannula. During the enlargement, the edge of the drop glides over the surface and the contact angle is determined. The retraction angle is measured on the same drop, only the water is withdrawn from the drop through the cannula and the contact angle is measured while the drop is being reduced. The difference between the two angles is called hysteresis. The smaller the difference, the less the interaction of the water drop with the surface of the surface and the better the lotus effect (the self-cleaning property).

The surfaces according to the invention, which have a surface structure with self-cleaning properties, preferably have an aspect ratio of the elevations of greater than 0.15. The elevations which are formed by the particles themselves preferably have an aspect ratio of 0.3 to 0.9, particularly preferably 0.5 to 0.8. The aspect ratio is defined as the quotient from the maximum height to the maximum Width of the structure of the surveys.

In order to achieve the aspect ratios mentioned, it is advantageous if at least some of the particles, preferably more than 50% of the particles, are only embedded up to 90% of their diameter in the surface of the film. The surface therefore preferably has particles which are anchored in the surface with 10 to 90%, preferably 20 to 50% and very particularly preferably 30 to 40% of their mean particle diameter and thus still protrude from the film with parts of their inherently fissured surface , This ensures that the elevations which are formed by the particles themselves have a sufficiently large aspect ratio of preferably at least 0.15. In this way it is also achieved that the firmly connected particles are very durable connected to the surface of the film. The aspect ratio is defined here as the ratio of the maximum height to the maximum width of the elevations. An assumed spherical particle that projects 70% from the surface of the surface extrudate has an aspect ratio of 0.7 according to this definition.

The microparticles firmly attached to the surface, which form the elevations on the surface of the film, are preferably selected from silicates, minerals, metal oxides, metal powders, silicas, pigments or polymers, very particularly preferably from pyrogenic silicas, precipitated silicas, aluminum oxide, mixed oxides Silicates, titanium dioxide or powdered polymers.

Preferred microparticles have a particle diameter of 0.02 to 100 μm, particularly preferably from 0.1 to 50 μm and very particularly preferably from 0.1 to 30 μm. Suitable microparticles can, however, also have a diameter of less than 500 nm or aggregate from primary particles to form agglomerates or aggregates with a size of 0.2 to 100 μm.

Particularly preferred microparticles which form the elevations of the structured surface are those which have an irregular fine structure in the nanometer range on the

Have surface. The microparticles with the irregular fine structure preferably have elevations or fine structures with an aspect ratio of greater than 1. particularly preferably greater than 1.5. The aspect ratio is in turn defined as the quotient from the maximum height to the maximum width of the survey. The difference between the elevations formed by the particles and the elevations formed by the fine structure is illustrated schematically in FIG. 1. FIG. 1 shows the surface of a surface extrudate X which has particles P (only one particle is shown to simplify the illustration). The survey, which is formed by the particle itself, has an aspect ratio of approx. 0.71, calculated as the quotient from the maximum height of the particle mH, which is 5, since only the part of the particle that contributes to the survey protrudes from the surface of the surface extrudate X, and the maximum width mB, which is 7 in relation to it. A selected elevation of the elevations E, which are present on the particles due to the fine structure of the particles, has an aspect ratio of 2.5, calculated as a quotient from the maximum height of the elevation mH ′, which is 2.5 and the maximum width mB ', which is 1 in proportion.

Preferred microparticles which have an irregular fine structure in the nanometer range on the surface are those particles which have at least one compound selected from pyrogenic silica, precipitated silica, aluminum oxide, mixed oxides, doped silicates, titanium dioxide or powdery polymers.

It can be advantageous if the microparticles have hydrophobic properties, the hydrophobic properties being able to go back to the material properties of the materials present on the surfaces of the particles themselves or can be obtained by treating the particles with a suitable compound. The microparticles may have been provided with hydrophobic properties before or after application to the surface of the surface extrudate.

To hydrophobize the particles before or after application to the surface, they can be treated with a compound which is suitable for hydrophobing, e.g. from the group of alkylsilanes, fluoroalkylsilanes or disilazanes.

Very preferred microparticles are explained in more detail below. The particles can come from different areas. For example, it can be silicates, doped silicates, minerals, metal oxides, aluminum oxide, silicas or titanium dioxide, aerosils or powdered polymers, such as. B. spray-dried and agglomerated emulsions or cryomilled PTFE. Particularly suitable particle systems are hydrophobicized pyrogenic silicas, so-called Aerosile ^® . In addition to the structure, a hydrophobicity is also necessary to generate the self-cleaning surfaces. The particles used can themselves be hydrophobic, such as powdered polytetrafluoroethylene (PTFE). The particles can be made hydrophobic, such as the Aerosil VPR 411 ^® or Aerosil R 8200 ^® . However, they can also be made hydrophobic afterwards. It is immaterial whether the particles are hydrophobicized before or after application. Such particles to be hydrophobicized are, for example, Aeroperl 90/30 ^® , Sipernat silica 350 ^® , aluminum oxide C ^® , zirconium silicate, vanadium-doped or Aeroperl P 25/20 ^® . In the latter case, the hydrophobization is expediently carried out by treatment with perfluoroalkylsilane compounds and subsequent tempering. Particularly preferred particles are the Aerosile ^® VPLE 8241, VPR411 and R202 from Degussa AG.

In the layers of microparticles which are firmly anchored in the film between two layers of thermoplastic, the microparticles are preferably at an average distance from one another of 0 to 10 particle diameters, preferably 3 to 5 particle diameters from one another. The number of layers of microparticles is limited by the number of layers of thermoplastic materials. In principle, there can be a layer of microparticles between each plastic layer and the subsequent plastic layer. In addition to these layers, the film can also have a further microparticle layer on each surface side. The multilayer film according to the invention thus has at most one more microparticle layer than there are plastic layers. However, it can also be advantageous if there is a layer of microparticles only between every second or third plastic layer, or else in completely irregular sequences.

As described above, the film according to the invention has at least two layers, preferably from 2 to 7 layers, particularly preferably from 3 to 5 layers, of thermoplastic materials. These can be selected from the materials usually used for extrusion. The thermoplastics are preferably selected from polycarbonates, polyoxymethylenes, poly (meth) acrylates, polyamides, Polyvinyl chloride, aliphatic linear, cyclic or branched polyalkenes, polystyrenes, polyesters, polyacrylonitrile or polyalkylene terephthalates, poly (vinylidene fluoride), or other polymers as homo- or copolymer or biodegradable raw materials, for example polylacetates, and mixtures thereof.

The film according to the invention can have layers of the same and / or different thermoplastic materials. The foils can also have several layers made of one and the same plastic and additionally several layers made of different plastics. Preferred films in particular have layers which all have the same plastic. Likewise preferred layers have outer layers which are made of a different plastic than the inner layers.

The films according to the invention are preferably obtainable by a process which is based on the known blow molding process. This procedure is described in detail e.g. described in "Introduction to plastics processing", Walter Michaeli, Carl Hanser Verlag Munich, 1999. Film blowing is a continuous primary molding process for the production of flexible film tubes made of thermoplastic materials. Film blowing works according to the following process: When blowing, a vertically upward extrusion is carried out Biaxial tube is stretched in the circumferential direction and by pulling rollers in the longitudinal direction by a factor of 6. If necessary, the film thickness is reduced by a factor of 30. In relation to the reduced thickness, the tensile strength is increased, but the permeability is reduced The film tube is laid flat. The volume of the air does not change in the inflated tube. However, it is constantly replaced through the mandrel with new cold air in order to accelerate the cooling of the tube and thus reduce the height of the machine. By welding Bags and cross cutting produce bags.

From the hoses, slides can also be created, which then have twice the width of the hoses. The film width can be up to 16 m and more after being cut open. Foil blowing systems, such as those manufactured by Kuehne, Sankt Augustin, use thermoplastic materials and, in a first step, provide tubes with widths in the range from 200 to 8,000 mm. This Systems can be operated as both mono and multi-shift systems. Up to 7 layers can be extruded on coextrusion lines. The line speed is up to 300 m / min. The film thickness varies between 5.5 and 250 μm. The systems are suitable for thermoplastics such as polyolefins, HD / PE, LDPE, LLD-PE, metallocenes, MD-PE, PP, PS, PA, EVA, EVOH and biodegradable raw materials.

The multilayer films according to the invention are e.g. available with the procedure described below. The process according to the invention for producing multilayer films according to the invention with at least one surface which has a surface structure with self-cleaning properties, the surface structure being formed by a firmly anchored layer of microparticles, is distinguished by the fact that the multilayer films are produced by means of a film blowing process, in which several layers of thermoplastic materials are blown into each other, whereby to produce a layer of microparticles between two layers of thermoplastic material after inflating a first layer of thermoplastic material and before the thermoplastic material has solidified, microparticles are applied to this layer, which after solidification the layer are fixed to this and then a further layer of thermoplastic material is blown into the first layer coated with microparticles and to He Creation of a surface which has a surface structure with self-cleaning properties, the surface structure being formed by a firmly anchored layer of microparticles, microparticles are applied to the first blown layer on the outside and / or the last blown layer inside, which solidify after the respective layer has solidified are fixed to this. In this way, multilayer films are available which have microparticles inside the film and on one or both surfaces.

When the individual layers are blown into one another, two or more layers can be produced from the same or different thermoplastics, depending on which plastics are used in the respective extruders.

All can be used on a conventional film blowing system Feedstocks. A material selected from polymers based on polycarbonates, polyoxymethylenes, poly (meth) acrylates, polyamides, polyvinyl chloride, aliphatic linear, cyclic or branched polyalkenes, polystyrenes, polyesters, polyacrylonitrile or polyalkylene terephthalates is particularly preferred for producing the layers from thermoplastic plastics , Poly (vinylidene fluoride), or other polymers as homo- or copolymer or biodegradable raw materials, for example polylactates, and mixtures thereof.

The layers of thermoplastic are preferably produced in a thickness of 0.002 to 0.25 mm, preferably 0.0075 to 0.1 and particularly preferably 0.01 to 0.025.

The multilayer films produced by means of the method according to the invention have at least two, preferably from 2 to 7 and particularly preferably from 3 to 6, layers of thermoplastic material. Layers of microparticles are produced between one, all or some of these layers and on the inner and / or the outer plastic layer.

The microparticles used in the process according to the invention are preferably those which have at least one material selected from silicates, minerals, metal oxides, metal powders, silicas, pigments or polymers. Microparticles are preferably used which have a particle diameter of 0.02 to 100 μm, particularly preferably from 0.1 to 50 μm and very particularly preferably from 0.1 to 30 μm. Microparticles with diameters of less than 500 nm can also be used. However, microparticles which are composed of primary particles to form agglomerates or aggregates with a size of 0.2 to 100 μm are also suitable.

Preferably used as microparticles, in particular as particles which have an irregular fine structure in the nanometer range on the surface, are those particles which have at least one compound selected from pyrogenic silica, precipitated silica, aluminum oxide, mixed oxides, doped silicates, titanium dioxide or powdery polymers. Preferred particles that have an irregular fine structure in the Due to this fine structure, the nanometer area on the surface has elevations which have an aspect ratio of greater than 1, particularly preferably greater than 1.5 and very particularly preferably greater than 2.5. The aspect ratio is in turn defined as the quotient from the maximum height to the maximum width of the survey.

The microparticles preferably have hydrophobic properties, the hydrophobic properties being able to be attributed to the material properties of the materials present on the surfaces of the particles themselves or else can be obtained by treating the particles with a suitable compound. The particles that are applied to the outer surface can be given hydrophobic properties before or after being embedded in the surface.

To make the microparticles hydrophobic, they can be treated with a compound which is suitable for hydrophobicizing, e.g. from the group of alkylsilanes, fluoroalkylsilanes or disilazanes.

The microparticles used with preference are explained in more detail below. The particles used can come from different areas. For example, it can be silicates, doped silicates, minerals, metal oxides, aluminum oxide, silicas or titanium dioxide, Aerosile ^® or powdered polymers, such as. B. spray-dried and agglomerated emulsions or cryomilled PTFE. Particularly suitable particle systems are hydrophobicized pyrogenic silicas, so-called Aerosile ^® . In addition to the structure, a hydrophobicity is also necessary to generate the self-cleaning surfaces. The particles used can themselves be hydrophobic, such as PTFE. The particles can be made hydrophobic, such as the Aerosil VPR 411 ^® or Aerosil R 8200 ^® . However, they can also be made hydrophobic afterwards. It is immaterial whether the particles are hydrophobicized before or after application. Such particles to be hydrophobicized are, for example, Aeroperl 90/30 ^® , Sipernat silica 350 ^® , aluminum oxide C ^® , zirconium silicate, vanadium-doped or Aeroperl P 25/20 ^® . In the latter case, the hydrophobization is expediently carried out by treatment with perfluoroalkylsilane compounds and subsequent tempering. Particles which are particularly suitable for the production of the multilayer films according to the invention are, for example, Degussa AG is offered as Aerosil ^® VPLE 8241, VPR411 and R202.

The particles can be applied in various ways. The particles are preferably applied to the layers which have not yet solidified by spraying or powdering. The particles are very particularly preferably applied by means of electrostatic spray processes, e.g. with an electrostatic spray gun. Depending on the point in time at which the particles are applied after leaving the extruder and inflating the layer, depending on the softness of the thermoplastic material of the layer, the microparticles penetrate further or less deeply into the plastic layer. In order to achieve the best possible connection, the plastic of the layer should be so soft that the particles can penetrate the layer with up to 90% of its circumference, care being taken in particular when producing the inner and / or outer layers that the particles do not penetrate more than 90% of their circumference into the layer, since otherwise a very good connection / fixation is achieved, however, no self-cleaning effect, since the particles do not form an elevation necessary for the self-cleaning effect without weathering of the layer material. Spraying takes place immediately after the polymer melt emerges from the ring nozzle. During the subsequent biaxial stretching of the film tube, the particles are distributed in the film layer. It is possible to use the process air to apply the particles.

By using the films produced by means of the method according to the invention, objects can be obtained which have a film according to the invention. Such items can e.g. Bags, tarpaulins, packaging, protective films, laminating or laminating films. The bags can also be obtained directly by the blowing process in which the tube obtained is not cut into a film. Bags can also be obtained by subsequently folding the film and then sealing it. Depending on whether the film used for their production has surface structures with a self-cleaning effect on one or both sides, the objects can be equipped with a self-cleaning surface either on the inside, on the outside or on the inside and outside.

The invention is explained in more detail with the aid of the figures 1 and 2. Figure 1 schematically shows the surface of a film X which has particles P (only one particle is shown to simplify the illustration). The survey, which is formed by the particle itself, has an aspect ratio of approx. 0.71, calculated as the quotient from the maximum height of the particle mH, which is 5, since only the part of the particle that contributes to the survey protrudes from the surface of the film X, and the maximum width mB, which is 7 in relation to it. A selected elevation of the elevations E, which are present on the particles due to the fine structure of the particles, has an aspect ratio of 2.5, calculated as a quotient from the maximum height of the elevation mH ′, which is 2.5 and the maximum width mB ', which is 1 in proportion.

2 shows a simple coextrusion machine in use in the method according to the invention. A film tube F is produced by the extruders El and E2. Microparticles, such as e.g. Aerosil VPR 411 can be applied to the inner surface of the hose. Depending on whether a further layer of plastic is blown inside the tube coated with microparticles, the microparticle layer is present on the surface of the film or inside the film.

The method according to the invention is described using the example below, without the invention being restricted to this exemplary embodiment.

Example:

A 0.008 mm thick PE-HD film (Hostalen, a high-density polyethylene from Basell) was blown on a film extrusion system from Windmöller & Hölscher (Germany / Lengerich) with a Varex coextrusion system. A second film of the same material was again blown onto the first layer in a thickness of 0.008 mm. A hydrophobic silica with an average particle size of 500 nm to 1 μm (Aerosil VPLE 8241 from Degussa AG) in a concentration of 50 to 250 mg / m ^{2 was} sprayed onto the not yet completely solidified polymer matrix of this last applied layer using an electrostatic spray gun. A third film layer was then made of the same material and the same thickness as the first two over this layer Blown layers. After solidification, the hose produced in this way was copied over corresponding deflection rollers on rollers and then cut open.

In contrast to films with a lotus effect on the outer surface, this film only showed a lotus effect after a weathering period in the Central European climate of 3 months. After this time, the first nanoparticles reached the surface because the film layer above them had weathered. After a period of about 3 to 12 months, all nanoparticles reach the surface and have a good lotus effect.

The quality of the lotus effect was determined by measuring the contact angle and the roll angle. The contact angle was determined optically on a water drop of 60 μl at 145 ° applied to the surface of the weathered film.

The roll angle was determined by pipetting on a 60 μl drop of water, a weathered film, which was applied to a glass plate, by tilting the glass plate until the water drop rolled off. This angle of inclination corresponds to the roll angle and was 0.5 °.

Since new nanoparticles are constantly being supplied, the lotus effect lasts much longer here than with a surface-coated film. The lifespan in relation to the lotus effect can be up to 3 years.

Claims

claims:

1. multilayer film made of thermoplastic material with at least one surface which has a surface structure with self-cleaning properties, the surface structure being formed by a firmly anchored layer of microparticles, characterized in that the film is formed by several layers of thermoplastic material, with at least between Two such layers have a layer of firmly anchored microparticles.

2. Film according to claim 1, characterized in that the surface structure formed by the microparticles has elevations with an average height of 20 nm to 25 μm and an average distance of 20 nm to 25 μm.

3. Film according to claim 2, characterized in that the particles are anchored in the surface with 10 to 90% of their mean particle diameter.

4. Film according to one of claims 1 to 3, characterized in that in the layer of firmly anchored microparticles between at least two layers of thermoplastic plastic, the microparticles in a middle

Distance from 0 to 10 of their particle diameter to each other.

5. Film according to one of claims 1 to 4, characterized in that the microparticles are nanostructured microparticles which have a fine structure

Have surveys with an aspect ratio greater than 1.

6. Film according to one of claims 1 to 5, characterized in that the microparticles are selected from particles of silicates, minerals, metal oxides, metal powders, silicas, pigments and / or polymers.

7. Film according to one of claims 1 to 6, characterized in that the microparticles are selected from particles of pyrogenic silicas, precipitated silicas, aluminum oxide, mixed oxides, doped silicates, titanium dioxides or powdery polymers.

8. Film according to one of claims 1 to 7, characterized in that the microparticles have hydrophobic properties.

9. Film according to one of claims 1 to 8, characterized in that the microparticles have an average particle size (diameter) of 0.02 to 100 microns.

10. Film according to one of claims 1 to 9, characterized in that the film has several layers of thermoplastics selected from polycarbonates, polyoxymethylenes, poly (meth) acrylates, polyamides, polyvinyl chloride, polyolefins, polyethylenes, polypropylenes, aliphatic linear or branched

Polyalkenes, cyclic polyalkenes, polystyrenes, polyesters, polyacrylonitrile or polyalkylene terephthalates, poly (vinylidene fluoride), or other polymers made of poly (isobutene), poly (4-methyl-1-pentene), polynorbomene as homo- or copolymer or biodegradable raw materials and the like Mixtures.

11. A film according to claim 10, characterized in that that the film has layers of the same and / or different thermoplastic materials.

12. A method for producing multilayer films according to one of claims 1 to 11 with at least one surface having a surface structure with self-cleaning

Features, wherein the surface structure is formed by a firmly anchored layer of microparticles, characterized in that the multilayer films are produced by means of a film blowing process in which several layers of thermoplastic materials are blown into each other, whereby to produce a layer of microparticles between two layers of thermoplastic Plastic after inflation of a first layer of thermoplastic and before the thermoplastic solidifies, microparticles are applied to this layer, which are fixed to the layer after the layer has solidified, and then a further layer of thermoplastic

Plastic is blown into the first layer coated with microparticles and to produce a surface which has a surface structure with self-cleaning properties, the surface structure being formed by a firmly anchored layer of microparticles, onto the first blown layer outside and / or the last blown layer microparticles are applied inside, which are fixed to the respective layer after it solidifies.

13. The method according to claim 12, characterized in that two or more layers of the same or different thermoplastic

Plastics are manufactured.

14. The method according to claim 12 or 13, characterized in that to produce the layers of thermoplastic materials, a material selected from polymers based on polycarbonates, polyoxymethylenes, poly (meth) acrylates, polyamides, polyvinyl chloride, polyethylenes, polypropylenes, aliphatic linear or branched polyalkenes, cyclic polyalkenes, polystyrenes, polyesters, polyacrylonitrile or polyalkylene terephthalates, poly (vinylidene fluoride), or other polymers of poly (isobutene), poly (4-methyl-l-pentene), polynorbones as homo- or copolymer or biodegradable raw materials and their mixtures.

15. The method according to at least one of claims 12 to 14, characterized in that the layers of thermoplastic material are produced in a thickness of 0.002 to 0.05 mm.

16. The method according to any one of claims 12 to 15, characterized in that multilayer films are produced which have from 2 to 7 layers of thermoplastic material.

17. The method according to at least one of claims 12 to 16, characterized in that the microparticles used have an average particle diameter of 0.02 to 100 microns.

18. The method according to at least one of claims 12 to 17, characterized in that microparticles selected from silicates, minerals, metal oxides, metal powders, silicas, pigments or polymers are used

19. The method according to at least one of claims 12 to 18, characterized in that the microparticles used have hydrophobic properties.

20. The method according to claim 19, characterized in that the microparticles have hydrophobic properties when treated with a suitable compound.

21. The method according to claim 20, characterized in that the particles are applied by means of electrostatic spraying processes.

22. Objects comprising a film according to one of claims 1 to 11.

23. The article according to claim 22, characterized in that it is a bag, a tarpaulin, packaging, protective films, laminating or laminating films.