DE102014119309A1 - Use of a plastic material and method of applying and then separating a fiber reinforced mat from a metallic surface - Google Patents

Abstract

The invention relates to a use of a plastic material (18) as a separating means (18) between a metallic surface (12) and at least one fiber-reinforced mat (14) applied flat to the metallic surface (12) with a thermoplastic at least partially surrounding the fibers (15) Matrix (16), wherein the plastic material (18) has a melt volume flow rate of between 0.02 times to 0.35 times, preferably between 0.08 times to 0.2 times, more preferably between 0.1 times to 0.15 times the melt volume flow rate of the thermoplastic matrix (16). The invention further relates to a method for applying and then separating at least one fiber-reinforced mat (14) from at least one metallic surface (12).

Description

Background of the invention

The present invention relates to the release of at least one fiber-reinforced mat with a thermoplastic matrix at least partially surrounding the fibers from a metallic surface.

It is known from one or more of these fiber-reinforced mats, a fiber-reinforced three-dimensional molded part, e.g. to manufacture a battery case of a traction battery of an electric vehicle by consolidating and / or plastically forming the mat or pads in a mold. The plastic deformability is typically provided by heating the thermoplastic matrix in which the fibers are embedded to above or above the melting temperature thereof.

If a plurality of these mats are provided for the production, it is also known to form a preform from this plurality before shaping in the molding tool or pressing tool, from which in the molding train the molding or component by shaping or deformation of the preform is formed. In this case, the preform is usually formed by depositing the mats on a workpiece carrier and building it up continuously to form the preform.

In the forming train at least one fiber-reinforced mat is brought into surface contact with at least one metallic surface of the mold. Even when depositing and continuously constructing the mats on the workpiece carrier, a fiber-reinforced mat is generally brought into area contact with at least one metallic surface of the workpiece carrier at least in regions.

In particular, when the mat is in a heated or heated state and / or when the respective metallic surface is in a heated or heated state, the plastic material or the thermoplastic matrix of the mat may adhere to the metallic surface. If you want to dissolve the mat in particular in the hot or heated state of the metallic surface, it may come when loosening tearing or tearing of thermoplastic material from the thermoplastic matrix of the fiber reinforced mat, said torn thermoplastic material of the thermoplastic matrix on the metallic surface remains or continues to adhere there.

In order to avoid this undesired disadvantageous tearing when loosening or separating the mats from the metallic surfaces-or to enable a residue-free removal or separation of the mats from the metallic surfaces-in known solutions the heated metal surfaces and / or the heated or heated mats cooled very expensive or there are provided foreign alien coatings. These release coatings are release coatings consisting of a plastic material selected from a group of materials that does not match the material group from which the thermoplastic matrix is selected.

In particular, the plastic material of the release coating may be a plastic material in the form of a liquid release agent, e.g. based on silicone oil, PTFE or other fats or a plastic material in the form of powders, e.g. based on PTFE, act. Although these release agents can allow a sufficient separation, but are registered to a certain extent in the mats. Furthermore, these release agents, especially the fats and silicone oils, are not easy to handle and must be laboriously removed from the surface of the mat so as not to interfere with subsequent process steps, such as e.g. a painting process to be introduced.

Underlying task

It is an object of the invention to provide an alternative solution with which a residue-free or almost residue-free dissolution of a fiber-reinforced mat with a fibers at least partially surrounding the thermoplastic matrix of a metallic surface without much effort is also possible if the surface and / or Mat is in a heated state or was.

Inventive solution

This object is achieved with a use with the features of claim 1 and a method with the features of claim 8.

The inventively provided use relates to a use of a plastic material as a release agent or release material between a metallic surface and at least one surface of the metallic surface fiber reinforced mat with a fibers at least partially surrounding thermoplastic matrix, wherein the plastic material has a melt volume flow rate between 0.02 times to 0.35 times, preferably between 0.08 times to 0.2 times, more preferably between 0.1 times to 0.15 times the melt volume flow rate of the thermoplastic matrix.

The melt volume flow rate (also sometimes called the melt flow index) characterizes the flow behavior of a thermoplastic material under certain pressure and temperature conditions. The measurement of the melt volume flow rate takes place in one in the German standard DIN EN ISO 1133-1 described manner using a standardized measurement setup described in this standard. The melt volume-flow rate is indicated cm ^3/10 min and measured in the unit at a specific test temperature and at a specific test load or nominal load in the German standard DIN EN ISO 1133-1 are described or defined in more detail. The melt volume flow rate of a substance is always specified here in conjunction with the test temperature and the nominal load or test load at which the melt volume flow rate was determined.

The melt volume flow rate is a measure of the viscosity of a plastic melt or of a thermoplastic material. The smaller the melt volume flow rate of a thermoplastic material at the given pressure and temperature conditions the greater its viscosity at these conditions.

According to the invention, the use of a plastic material as release agent or release material between the metallic surface and the at least one fiber-reinforced mat applied flat on the metallic surface is therefore provided, which has a melt volume flow rate of between 0.02 times and 0.35 times. times, preferably between 0.08 times to 0.2 times, more preferably between 0.1 times to 0.15 times the melt volume flow rate of the thermoplastic matrix.

A plastic material with such a substantially smaller melt volume flow rate than the melt volume flow rate of the thermoplastic matrix of the mat has a significantly higher viscosity than the thermoplastic matrix of the mat, so that molecules of this release agent can be very difficult to be dissolved out of the molecular structure or molecular composite , Even in the heated state of the metallic surface and / or the fiber-reinforced mat can therefore by using the plastic material with the much smaller melt volume flow rate as a release agent advantageously and without much effort an effective separation and thus a residue-free or almost residue-free release of the fiber-reinforced mat of the metallic surface are allowed. When removing or stripping the fiber-reinforced mat from the metallic surface, the release agent - or applied in the form of at least one release layer on the metallic surface release agent - are removed without residue or free of residue from the metallic surface, wherein the release agent or the release layer may remain adhered to the fiber reinforced mat after peeling. The fact that the release agent adheres to the fiber - reinforced mat after removal - or can be deducted without residue or almost residue - free by removing or removing the fiber - reinforced mat from the metallic surface - results from the connection force or holding force between the mat and the release agent of the separating layer, which is formed larger than the connecting force or holding force between the separating agent or the separating layer and the metallic surface.

The production of a fiber-reinforced mat which has a thermoplastic matrix having a low melt volume flow rate provided for by the release agent according to the invention is not possible because of the complete or at least partial embedding of the fibers into the thermoplastic due to the high viscosity associated with this low melt volume flow rate Matrix is not possible or only with great technical effort. Further, mats having a thermoplastic matrix with such a small melt volume flow rate would not be suitable for use as mats to be formed in a mold.

The reinforcing fibers or fibers of the mat are preferably mineral fibers, in particular glass fibers or basalt fibers, and / or carbon fibers, and / or aramid fibers and / or polymeric fibers, and / or synthetic fibers and / or fibers of renewable raw materials. Furthermore, the reinforcing fibers may be short fibers and / or long fibers and / or continuous fibers.

The melt volume flow rate of the plastic material used as the release agent, which is between 0.02 times to 0.35 times, preferably between 0.08 times to 0.2 times, more preferably between 0.1 times to 0.15 times the melt volume flow rate of the thermoplastic matrix is preferably a melt volume flow rate determined at the same test temperature and load as the melt volume flow rate of the thermoplastic matrix of the mat or substantially at matching test temperatures and substantially identical test loads or nominal loads was determined. Preferably, the test temperature and the test load are one in the DIN EN ISO 1133-1 Recommended or proposed test temperature and test load or rated load for the plastic material used.

Particularly advantageously, the melt volume flow rate at the same test temperature and test load or rated load is determined as the melt volume flow rate of the mat thermoplastic matrix (or substantially at the same test temperature and at the same test load or rated load), if the release agent and the thermoplastic matrix from one and the same material group or material group are selected. For example, the release agent and the thermoplastic matrix may each be selected from the material group or material group of polyolefins, preferably the polypropylene, or the polyamides selected materials or materials. Materials from the same material group can be provided according to the invention by measuring the melt volume flow rate of the thermoplastic matrix of the mats and the melt volume flow rate of the release agent at matching test temperatures and test loads or at substantially matching test temperatures and test loads melt volume flow rates.

If the release agent and the thermoplastic matrix are selected from different material groups or material groups, the test temperature and the test load or nominal load for the measurement of the melt volume flow rate of the thermoplastic matrix and the test temperature and the test load or nominal load for the measurement of the melt Volume flow rate of the release agent advantageously adapt to the rheological properties of the thermoplastic matrix and the release agent, especially if matching or substantially identical test temperatures and test loads are not feasible due to these rheological properties or not deliver usable results.

In a preferred embodiment of the inventive use, the plastic material is used as a release agent when the fiber-reinforced mat applied to the metallic surface is to be separated from the metallic surface in a heating state.

Both the release agent and the mat are at least partially in a molten state at temperatures according to this preferred embodiment after a certain heating time, wherein the release agent then at least partially in the form of at least one molten separating layer or melt layer between the mat and the metallic surface is. In particular, at the temperatures according to this preferred embodiment, the fiber-reinforced mat together with the release material or the release layer of the metallic surface residue-free or almost residue-free - ie without or almost no residual material left on the metallic surface - deducted or removed from this , This has great advantages especially in the mass production of a plurality of fiber-reinforced molded parts or three-dimensional components of one or more fiber-reinforced mats, as set forth below.

The components, such as A housing of a traction battery of a motor vehicle, are prepared by consolidating and / or plastic forming or deformation of the at least one mat on at least one metallic surface or a metallic forming surface in a mold or pressing tool. The plastic deformability is provided by heating the thermoplastic matrix into which the fibers are at least partially or entirely embedded up to or above the melting temperature thereof. After shaping or pressing in the mold on the at least one metallic surface, the mats or the component - by the use of the release agent with the inventively provided melt volume flow rate - in the heating state advantageously without much effort and residue-free or almost residue-free of at least a metallic surface or molding surface to be separated, without having to accept time-consuming cooling processes in purchasing. Advantageously, in this way, in the mass production of a plurality of fiber-reinforced molded parts or components made of one or more fiber-reinforced mats, the unit performance can be significantly increased or optimized. After the forming or pressing in the mold at the at least one metallic surface, the mats or the component - by the use of the separating means with the inventively provided melt volume flow rate - even after cooling or cooling of the metallic surface advantageously without large Effort and residue-free or almost residue-free from the at least one metallic surface or mold surface are separated, since it is advantageously not come to a significant adhesion of the mats or the component in the heating state.

Under consolidation according to the invention is a compaction or compacting of the mat or mats to understand. During consolidation, air taken in through the compartments, in particular in the mats, can escape from the mats due to compacting or compaction. By deforming and / or consolidating, if more mats are used, at least in some areas Forming cohesive connections between the individual mats take place.

If a plurality of these mats are provided for the production of the molded part, it is also known to form a preform from this plurality before forming and / or consolidating in the mold, from which the molded part or component in the forming train by consolidating and / or or molding the preform. The preform is usually formed by the fact that the mats are stored on a workpiece carrier and continuously built up to the preform. For this purpose, by using the release agent with the melt volume flow rate provided according to the invention advantageously without much effort and residue-free or almost residue-free - ie in particular without material residues or hardly residual material of the release agent on the metallic surface of the workpiece carrier to leave - in the heating state the above preferred embodiment, a separation of the at least one mat are made of a metallic surface of the workpiece carrier. This separation can therefore be carried out in particular advantageously without time-consuming cooling processes, along with a substantial increase in the number of parts in the series production of a large number of fiber-reinforced molded parts or components from one or more mats. By heating or heating of the mats already on the tool carrier, the cost of the required heating or heating in the respective mold or pressing tool can be significantly reduced.

The use of the release agent with the inventively provided melt volume flow rate is due to the above particularly advantageous for heating or heating of the mat or mats on a metallic heating surface for preheating or preheating for subsequent molding or pressing in a mold or Press tool.

The use of the release agent with the melt volume flow rate provided according to the invention can also be advantageous in double-belt presses, calenders or similar press systems in which one or more of the fiber-reinforced mats are pressed in a heated state to metallic surfaces or metallic mold surfaces.

In the case of different wall thicknesses of the component to be formed from the at least one mat or at different thicknesses of the at least one mat, the separating layer or the melt film can advantageously also have a leveling effect which leads to a more uniform pressure distribution and thus a better pressing or consolidation process in the forming train already before removal from the respective metallic surface.

If the release agent and the thermoplastic matrix are selected from one and the same material group or material group, the release agent or the at least one release layer after the separation process at least partially cohesively with the at least one mat or by deforming and / or consolidating the at least one mat formed component, if a separation in the heating state according to the above preferred embodiment takes place. An after the separation process with the at least one mat or the component cohesively connected separating layer has the advantages set out below.

As a result of the cohesive connection can advantageously be dispensed with a costly disposal or a complex recycling of the release agent. By a lower fiber content of the at least one mat or of the component in the region of the separating layer, a component with a visually very smooth surface and a high surface quality can be created. The very smooth surface and the high surface quality is particularly caused by the significantly higher compared to the component or the at least one mat viscosity of the release layer.

Insofar as the separating layer cohesively connected to the component or the at least one mat after the separating process causes an undesirable thickening of the component or the mat, a compensation by risers can be made, as is customary in metal casting, whereby the corresponding Material amount of the release layer is pressed out of the molding cavity to eliminate the unwanted thickening.

If, after the separation process, there is insufficient bonding of the separating layer to the component or the at least one mat, the separating layer can be replaced by subsequent heating, e.g. be leveled by flaming or flaming or by infrared radiation or by flowing hot air and connected to the component.

To select the release agent and the thermoplastic matrix of different and mutually incompatible material groups or material groups may be particularly advantageous if a cohesive connection between the thermoplastic matrix or the mat and the Release agent is not desirable and instead a simple release of the release agent from the mat, for example, after a deformation and / or consolidation is desired.

The plastic material used as the release agent may preferably be a powdered polypropylene, powdered polypropylene more preferably has a melt volume flow rate, the minimum within a range of 0.2 cm ^3/10 min to 5 cm ^3/10, preferably within a range of 0.5 cm ^3/10 min to 3 cm ^3/10 min. More preferably, the powder may have a grain size that is within a range of 0.1 mm to 3 mm. The melt volume flow rate of the aforementioned ranges is a melt volume flow rate, which was preferably measured or determined at a test temperature of 230 ° C and a test load of 2.16 kg.

The powder present at room temperature in powder form can be sprayed on the metallic surface in a simple and practical manner before applying the mat. By heating the polypropylene to or above the melting temperature - e.g. by spraying on an already heated metallic surface - the usually very inexpensive polypropylene powder can be melted, thereby forming at least one release layer or at least one release layer in the form of a melt layer or a melt film, which - if the polypropylene and the thermoplastic Matrix of at least one mat selected from the same material group are advantageous after the separation process with the component or the at least one mat at least partially cohesively connects, along with the advantages described above. Due to the very small grain size, a very uniform coverage of the metallic surface can be achieved at least in some areas, along with the formation of a very uniform coverage with at least one melt layer, which covers the metallic surface at least partially or completely.

Due to the low melt volume flow rates, a release film or melt film formed from this powder has only a very small adhesion to the metallic surface or is held to the metallic surface with only a very small holding force.

The powdered polypropylene, in particular in the preparation of a molding tool or pressing tool - which is intended to form a component of at least one fiber-reinforced mat by consolidation and / or plastic forming or deformation - allows a simple and practical feasible application of the release agent to the metallic Form surfaces or metallic surfaces of the mold or pressing tool by spraying.

Especially with simple tool geometries, the plastic material used as a release agent can be present as a film or as a mat. The plastic material used as a release agent can also be present as a fiber-reinforced film or as a fiber-reinforced mat.

• (A) wenigstens bereichsweises Aufbringen eines als Trennmittel vorgesehenen Kunststoffmaterials auf die Oberfläche, wobei das Trennmittel eine Schmelze-Volumenfließrate aufweist, die zwischen dem 0,02-fachen bis 0,35-fachen, vorzugsweise zwischen dem 0,08-fachen bis 0,2-fachen, weiter vorzugsweise zwischen dem 0,1-fachen bis 0,15-fachen der Schmelze-Volumenfließrate der thermoplastischen Matrix liegt,
• (B) Flächiges Anlegen der Matte an die metallische Oberfläche bzw. Anlegen der Matte an das Trennmittel bzw. Auflegen der Matte auf das Trennmittel,
• (C) wenigstens bereichsweises Erwärmen der metallischen Oberfläche und/oder der Matte, und
• (D) Trennen bzw. Entfernen der Matte von der metallischen Oberfläche.

The inventive method for applying and then separating at least one fiber-reinforced mat of at least one metallic surface comprises the following steps:

• (A) at least partially applying a plastic material intended as a release agent to the surface, wherein the release agent has a melt volume flow rate of between 0.02 times to 0.35 times, preferably between 0.08 times to 0, 2 times, more preferably between 0.1 times to 0.15 times the melt volume flow rate of the thermoplastic matrix,
• (B) applying the mat flat to the metallic surface or applying the mat to the release agent or placing the mat on the release agent,
• (C) at least partially heating the metallic surface and / or the mat, and
• (D) separating or removing the mat from the metallic surface.

By naming the steps with the letters A to D, no exclusive binding to a chronological order is pursued. The letters serve only to name or mark the steps. Thus, in step C, the metallic surface and / or the mat before and / or during and / or after step B are at least partially heated. In particular, the metallic surface and / or the mat can also be heated at least in regions before step A or during step A.

By applying the method according to the invention, a residue-free or almost residue-free dissolution or separation of a fiber-reinforced mat with a fiber at least partially or entirely surrounding the thermoplastic matrix of a metallic surface is possible without much effort. Both the release agent and the mat are at least partially in a molten state at the intended temperatures and the release agent is then arranged at least partially in the form of at least one molten separating layer or melt layer between the mat and the metallic surface. As also stated above, especially in these Temperatures the fiber-reinforced mat together with the release material or the release layer of the metallic surface residue-free or almost residue-free - ie without or almost no residual material of the release material or the mat on the metallic surface to leave - deducted or removed from this , The same applies to a cooled or cooled metallic surface.

The method according to the invention can advantageously be integrated into a production process for molding a three-dimensional component from at least one fiber-reinforced mat by consolidating and / or plastically shaping or deforming the mat in a molding tool or pressing tool. After deformation in the molding tool or pressing tool, the at least one fiber-reinforced mat or the component can advantageously be separated from the metallic surface without much effort and residue-free or almost residue-free because of the release agent with the melt volume flow rate provided in the heating state without having to accept time-consuming cooling processes. Advantageously, in this way in the mass production of a plurality of fiber-reinforced molded parts or components of one or more mats, the number of pieces can be significantly increased or optimized.

Also in the method according to the invention, the release agent and the thermoplastic matrix may preferably be selected from one and the same material group, along with the wide advantages described above.

Preferably, the release agent is a powdered polypropylene, powdered polypropylene more preferably has a melt volume flow rate, the minimum within a range of 0.2 cm ^3/10 5 cm ^3/10 min, along with the above-described advantages. In particular, the powdered polypropylene may preferably have a grain size which is within a range of 0.1 mm to 3 mm. By providing this very small grain size, as stated above, at least in some areas a very uniform coverage of the metallic surface can be achieved, along with the formation of a very uniform coverage with at least one release layer or melt layer which at least partially or to the metallic surface Completely covered.

Brief description of the drawings

Embodiments of the invention will be explained in more detail with reference to the accompanying drawings. It shows:

1A and B each show a schematic sectional view of a molding of a molding tool together with a fiber-reinforced mat and a separating means provided between the mat and the molding for illustrating an embodiment of the use according to the invention, and

2A to D schematic sectional views to illustrate an embodiment of the method according to the invention.

That in the 1A and 1B in sectional view schematically illustrated fitting 10 a mold (not shown in detail) has a molding surface 12 in the form of a metallic surface 12 on. To this metallic surface 12 can, as shown, a fiber-reinforced mat 14 - with one the fibers 15 (only very schematically illustrated by dashed lines) at least partially surrounding thermoplastic matrix 16 - be laid out flat. The fitting 10 is intended, in a mold, not shown here from the mat 14 an to the surface shape of the metallic surface 12 adapted deformed fiber reinforced mat 14 or a fiber-reinforced component by pressing and / or consolidating the mat 14 on the metallic surface 12 to build. Pressing the mat against the metallic surface 12 takes place here with a molding of the mold, not shown here, which corresponds to a corresponding to the metallic surface 12 having trained pressing surface.

As a release agent 18 between the metallic surface 12 and the flat mat 14 becomes a plastic material in the form of a powdery polypropylene at room temperature 18 (see. 1A ), which has a melt volume flow rate of between 0.02 times to 0.35 times, preferably between 0.08 times to 0.2 times, more preferably between 0.1 times to 0.15 times the melt volume flow rate of the thermoplastic matrix 16 lies.

Both the release agent 18 also the thermoplastic matrix 16 the mat 14 is after a certain heating time at least partially in a molten state, the plastic deformation of the mat 14 by pressing them to the metallic surface 12 is required. The powder at room temperature release agent 18 is by melting at these temperatures then in the form of a molten separating layer 18 or melt layer 18 between the mat 14 and the metallic surface 12 arranged (cf. 1B ). By providing the release agent 18 can after pressing and / or consolidating the mat 14 on the metallic surface 12 to make the fiber reinforced deformed mat 14 this together with the release agent 18 or the separating layer 18 from the metallic surface 12 residue-free or almost residue-free removal - ie without or without significant material residues of the release agent 18 on the metallic surface 12 to leave. If it is the thermoplastic matrix 16 - As with the release agent 18 - is a polypropylene, at least in some areas a cohesive connection between the release layer by pressing and / or consolidating 18 and the deformed mat 14 produced.

The 2A to D show schematic sectional views for illustrating an embodiment of the method according to the invention for the application and subsequent separation or removal of a fiber-reinforced mat 14 from a metallic surface 12 a fitting 10 a mold.

The 2A illustrates step A of the method in which a release agent 18 provided plastic material 18 on the metallic surface 12 is applied. The release agent 18 has a melt volume flow rate that is between 0.02 times to 0.35 times, preferably between 0.08 times to 0.2 times, more preferably between 0.1 times to 0.15 times the melt volume flow rate of the thermoplastic matrix 16 the fiber reinforced mat 14 which in step B (cf. 2 B ) by means of one with suction cups 20 provided gripping tool 22 - after application of the release agent 18 - flat against the metallic surface 12 created or placed on this or the release agent 18 is created.

The release agent 18 is in the form of a powdery polypropylene at room temperature 18 formed, which by spraying on the metallic surface 12 is applied to this. In step C, the heating of the metallic surface takes place 12 and the mat 14 to the thermoplastic matrix 16 the mat 14 for a plastic deformability at least partially convert into a molten state. The powder at room temperature release agent 18 is melted by heating and thereby forms a molten separating layer 18 or melt layer between the mat 14 and the metallic surface 12 (see. 2C ).

After the plastic deformation of the mat 14 by pressing it to the metallic surface 12 by means of a pressing tool not shown here and / or after consolidating the mat 14 on the metallic surface 12 is in step D (see. 2D ) the deformed mat 14 by means of the gripping tool 22 from the metallic surface 12 including the one with the mat 14 connected separating layer 18 residue-free or almost residue-free separation or removal. If it is the thermoplastic matrix 16 - As with the release agent 18 - is a polypropylene, is at least partially by pressing and / or consolidating a cohesive connection between the release layer 18 and the deformed mat 14 produced.

QUOTES INCLUDE IN THE DESCRIPTION

This list of the documents listed by the applicant has been generated automatically and is included solely for the better information of the reader. The list is not part of the German patent or utility model application. The DPMA assumes no liability for any errors or omissions.

Cited non-patent literature

• DIN EN ISO 1133-1 [0011]
• DIN EN ISO 1133-1 [0011]
• DIN EN ISO 1133-1 [0017]

Claims (11)

Use of a plastic material ( 18 ) as a release agent ( 18 ) between a metallic surface ( 12 ) and at least one to the metallic surface ( 12 ) surface-applied fiber-reinforced mat ( 14 ) with one of the fibers ( 15 ) at least partially surrounding thermoplastic matrix ( 16 ), wherein the plastic material ( 18 ) has a melt volume flow rate of between 0.02 times to 0.35 times, preferably between 0.08 times to 0.2 times, more preferably between 0.1 times to 0.15 times the melt volume flow rate of the thermoplastic matrix ( 16 ) lies. Use according to claim 1, characterized in that the release agent ( 18 ) and the thermoplastic matrix ( 16 ) are selected from one and the same material group. Use according to one of the preceding claims, characterized in that the release agent ( 18 ) is a powdered plastic material. Use according to claim 5, characterized in that the pulverulent plastic material comprises polypropylene and having a melt volume flow rate, the minimum within a range of 3 cm ^3/10 5 cm ^3/10 min, or within a range of 0.2 cm ³ / 10 min to 0.5 cm ^3/10 min. Use according to claim 5 or 6, characterized in that the powdery plastic material has a grain size which is within a range of 0.1 mm to 3 mm. Method for applying and then separating at least one fiber-reinforced mat ( 14 ) of at least one metallic surface ( 12 ), whereby the mat ( 14 ) one the fibers ( 15 ) at least partially surrounding thermoplastic matrix ( 16 ), and wherein the method comprises the following steps: (A) application of at least one area as release agent ( 18 ) provided plastic material ( 18 ) on the surface ( 12 ), wherein the release agent ( 18 ) has a melt volume flow rate of between 0.02 times to 0.35 times, preferably between 0.08 times to 0.2 times, more preferably between 0.1 times to 0.15 times the melt volume flow rate of the thermoplastic matrix ( 16 ), (B) planar application of the mat ( 14 ) to the metallic surface ( 12 (C) at least partially heating the metallic surface ( 12 ) and / or the mat ( 14 ), and (D) separating the mat ( 14 ) from the metallic surface ( 12 ). Method according to claim 8, wherein the metallic surface ( 12 ) and / or the mat ( 14 ) is heated at least in regions before and / or during and / or after step B. Method according to claim 8 or 9, characterized in that the release agent ( 18 ) and the thermoplastic matrix ( 16 ) are selected from one and the same material group. Method according to one of the preceding claims, characterized in that the release agent ( 18 ) is a powdered plastic material. A method according to claim 11, characterized in that the powdered synthetic-material comprises polypropylene and having a melt volume flow rate, the minutes to 5 cm ^3/10 within a range of 3 cm ^3/10 min, or within a range of 0.2 cm ^3/10 min to 0.5 cm ^3/10 min. A method according to claim 11 or 12, characterized in that the powdery plastic material has a grain size which is within a range of 0.1 mm to 3 mm.

Images