DE102020206033A1 - Process for the production of a fiber-reinforced material composite of plastic films and fiber material as well as material composite - Google Patents

Abstract

The present invention relates to a method for producing a fiber-reinforced material composite (1) which is formed from plastic and fiber material.
In order to propose a cost-effective and at the same time simple method for producing such a fiber-reinforced material composite (1) with improved mechanical properties compared to the prior art, the method according to the invention provides that the material composite (1) is designed in the form of a layer structure, wherein the fiber material for forming the layer structure is arranged between two plastic film layers (4a, 4b) and is connected to the plastic film of the respective plastic film layer (4a, 4b).
The invention also relates to a composite material (1) made of plastic and fiber material, the composite material (1) being designed in the form of a layer structure, and the fiber material being arranged between two plastic film layers (4a, 4b) and with the plastic film of the plastic film layers (4a, 4b) is connected.

Description

The invention relates to a method for producing a fiber-reinforced material composite which is formed from plastic and fiber material. The invention also relates to a composite material made of plastic and fiber material.

From the prior art, e.g. B. the EP2165821B1 , a method is known in which polymer films can be reinforced on one side by fiber material. For this purpose, a polymer film is heated and covered with aligned pieces of fiber. A vibration element is used to align the fiber pieces. The temperature of the polymer film is close to its melting point and the fibers are also impregnated so that the fibers adhere to the polymer film and then sink into the polymer of the film. The film produced in this way is also referred to as an organic film and provides a semi-finished product which can be further processed in suitable further processing steps. In this way, laminates can be produced inexpensively from organic films, or these can be further processed into three-dimensional structures using deep-drawing processes. The process is particularly suitable for recycling pieces of fiber and short fibers.

Fiber-reinforced foils produced by such a method have the disadvantage that the fibers are inhomogeneously distributed in the material and impregnation is necessary so that the fibers are enclosed by the polymer. Enclosing or embedding the fibers with the named polymer cannot always be reliably guaranteed either. Therefore, although the processes mentioned can be used for the cost-effective production of fiber-reinforced polymer films or for the recycling of fibers, the components produced with them have significant weaknesses in the area of mechanical stability.

The object of the invention is accordingly to propose a cost-effective and at the same time simple method for producing a fiber-reinforced material composite with improved mechanical properties compared to the prior art, as well as a material composite manufactured in this way.

This object is achieved by a method with the features of claim 1 and a material composite with the features of claim 13.

It should be pointed out that the features listed individually in the claims can be combined with one another in any technically meaningful way (also across category boundaries, for example between method and device) and show further embodiments of the invention. The description additionally characterizes and specifies the invention, in particular in connection with the figures.

It should also be pointed out that a conjunction “and / or” used here between two features and linking them must always be interpreted in such a way that only the first feature can be present in a first embodiment of the subject matter according to the invention, in a second embodiment only the second feature can be present and, in a third embodiment, both the first and the second feature can be present.

It is essential for the invention that the fiber material is embedded between two plastic film layers, which on the one hand enables a uniform distribution of fiber material in the composite material. On the other hand, partial areas of the composite material can also be specifically reinforced in which material reinforcement is necessary or desired. Furthermore, by embedding the fiber material between two plastic film layers, undesired discharge or abrasion of fiber material is avoided. The longevity of a component produced in this way is thus improved.

In a method according to the invention for producing a fiber-reinforced material composite, this is formed from plastic and fiber material. The method is characterized in that the material composite is formed in the form of a layer structure, the fiber material for forming the layer structure being arranged between two plastic film layers and being connected to the plastic films of the respective plastic film layers. In the material composite, a matrix for the fiber material is provided from the plastic of the plastic film layers, for example a thermoplastic plastic (in a material composite produced according to the method, the plastic thus provides a matrix for the fiber material). Thermoplastic plastics are suitable because they can be brought into a melted state in which they can absorb and enclose solid bodies, for example the fiber material, in order to then form a coherent solid body in which the fiber material is embedded when the fiber material is cooled down. In general, however, any type of plastic can be used for this purpose. The plastics used only have to be suitable for being able to enclose or embed fiber material in a certain state. These can include, for example, thermosets and elastomers, the use of thermoplastics being preferred according to the invention. Also plastics or other substances or mixtures of substances are used which are liquid or pasty at room temperature and only form a solid after curing. The last-mentioned curing can take place chemically or physically, with physical curing in particular being able to mean drying based on evaporation of a solvent.

The composite material is characterized by a layer structure, which is to be understood as the fact that plastic material or a plastic film layer is present above and below the introduced fiber material. In some areas, the layer structure can also be free of fiber material. A composite material produced in this way can therefore have fiber-reinforced partial areas and non-fiber-reinforced partial areas. The composite material can also be completely fiber-reinforced.

In the fiber-reinforced areas, it is advantageous if the plastic essentially encloses the fibers. According to the method, the fiber material is arranged between two plastic film layers, connected to the plastic films of the plastic film layers and, for example, surrounded by the plastic material of the plastic film layers in a form-fitting manner. The mentioned “connection” can be made in different ways, for example by thermal melting of the plastic and surrounding the fiber material by the plastic melt. The two plastic film layers do not necessarily have to be two individual films, but the layers can also be created by folding a film. The individual plastic film layers can also comprise several layers.

The advantageous refinements specified in the subclaims and further advantageous (or possible) refinements of the method proposed by the invention are described in detail below. As mentioned, the configurations described below can also represent configurations of the composite material also claimed by the invention.

According to a first embodiment of a method proposed by the invention, it can be provided that the fiber material is connected to the plastic film by introducing thermal energy, the thermal energy being introduced to the effect that the temperature of the plastic film when connecting the fiber material to the plastic film is above its Melting temperature is. If the plastic film or the plastic material on which it is based is meltable and has a melting point, it is advisable to heat the plastic film to temperatures close to or above the melting point and then to introduce the fiber material between the plastic film layers. In this way, the flowable plastic can surround the fibers of the fiber material and completely enclose the fibers. In this way, a physical connection (in the form of binding forces) between the fibers of the fiber material and the plastic material of the plastic film layers can also be provided, which is beneficial to the mechanical properties of the material composite. The plastic material of the plastic film layers can be heated by conduction, convection heat or thermal radiation. It can also be advantageous if only a small, delimited area of the foils is heated so that difficult handling of melted, flexible foils is limited to a minimum.

According to a further embodiment of a method proposed by the invention, it can be provided that the plastic film layers are formed by separate plastic films. It can be advantageous that the two plastic film layers are not provided by folding a single film, but rather by two separate films. For example, a folding device or a technically complex supply of the fiber material to a production unit can be dispensed with. It is also possible to realize material combinations of two different types of plastic for the respective plastic film layers. In this way, films with different mechanical properties can be joined together to form a material composite that combines the advantages of both film materials.

According to a further embodiment of a method proposed by the invention, it can be provided that the plastic film layers are formed by one and the same plastic film, the plastic film being folded in a folding area in such a way that the plastic film provides two plastic film layers. In this embodiment, only one plastic film is used to provide both plastic film layers, between which the fiber material is arranged. For this purpose, a plastic film can be passed through a suitable folding device which folds one half of the plastic film over the other half. The plastic film layers produced in this way can have the same or different size dimensions. A “folding” of the plastic film is therefore not necessarily to be understood as a symmetrical folding. It is conceivable that in a production unit having such a folding device for the composite material, the fiber material is arranged between the film layers at the same time. A previous arrangement of the fiber material on plastic film layers of the (folded) plastic film is just as conceivable as a subsequent introduction of the fiber material between the plastic film layers.

According to a further embodiment of a method proposed by the invention, it can be provided that the plastic film layers are connected to one another when the thermal energy is introduced. For an improved connection of the fiber material to the plastic film layers, it can be advantageous if the plastic film layers are softened or melted by means of thermal energy and thus connected to the fiber material. After the plastic material has hardened, a firm connection to the fiber material is provided.

According to a further embodiment of a method proposed by the invention, it can be provided that the fiber material is connected to the plastic film of the plastic film layers with the application of pressure. The plastic film layers can be fused with one another and with the fiber material by applying pressure. An advantage here can be that the plastic material of the plastic film layers is shaped around the fibers of the fiber material in a manner adapted to shape by the pressure application, so that a substantially full-area contact of the fiber surface with the plastic film layers is achieved. A combination of the introduction of additional thermal energy and pressure can promote the process. The pressure can be applied by simple pressing, rolling or combined heating presses / heating rollers. The advantage of a, for example, combined heating press in roller design is that the composite material can be manufactured in a continuous process. The layer system consisting of the two plastic film layers with the fiber material arranged in between is guided through heated rollers, which simultaneously apply temperature and pressure through the line contact between the rollers and the layer system and thus connect the layer system to one another.

According to a further embodiment of a method proposed by the invention, it can be provided that the fiber material comprises fibers, in particular unidirectionally oriented continuous fibers, which are oriented essentially in parallel. Unidirectional means that all or the majority of the fibers are aligned in one direction. Such a parallel alignment of the fibers contributes to an increase in the mechanical stability of the subsequent material composite, in particular in the direction of extension of the fibers.

According to a further embodiment of a method proposed by the invention, it can be provided that only partial areas of the composite material are fiber-reinforced. It may be desirable not to reinforce the entire surface of the composite material with fibers. In order to save material and weight, only those areas of the composite material that are exposed to heavy loads in an application can be reinforced by fiber material, while areas with lower loads only comprise plastic film layers. These can be continuous partial areas along or transversely to the feed direction of the plastic film layers or island-shaped partial areas which require increased strength and / or rigidity. A further embodiment can be such that fiber material is only provided in partial areas along a material composite axis and thus partial areas are fiber-reinforced and non-fiber-reinforced alternately in a direction transverse to the material composite axis. By alternating areas of fiber-reinforced and non-fiber-reinforced sub-areas transversely to the aforementioned material composite axis, a material composite with increased mechanical properties in the direction of the material composite axis can be created, while at the same time significant fiber material can be saved. A material composite designed in this way can also be manufactured continuously without any problems, since the direction of the fiber material corresponds to the manufacturing direction.

1. a. Anordnen einer ersten Kunststofffolien-Lage auf einem Träger;
2. b. Anordnen von Fasermaterial auf einer dem Träger abgewandten Oberfläche der ersten Kunststofffolien-Lage;
3. c. Anordnen einer zweiten Kunststofffolien-Lage auf dem Fasermaterial;
4. d. Verbinden des Fasermaterials mit der ersten und zweiten Kunststofffolien-Lage unter Einbringung von thermischer Energie und/oder unter Aufbringung von Druck.

According to a further embodiment of a method proposed by the invention, it can be provided that the following steps are carried out:

1. a. Arranging a first plastic film layer on a carrier;
2. b. Arranging fiber material on a surface of the first plastic film layer facing away from the carrier;
3. c. Arranging a second plastic film layer on the fiber material;
4. d. Connecting the fiber material to the first and second plastic film layers with the introduction of thermal energy and / or with the application of pressure.

This sequence of steps lends itself to a batch production of the fiber-reinforced material composite, since the individual layers of plastic film layers and fiber material can be arranged and connected to one another without complex feeding. The carrier can have a flat surface, for example the lower press plate of a hot press. In the hot press or a later process step, thermal energy or pressure is then applied or applied to the layered material in order to connect the components mentioned to one another.

1. a. Zuführen einer ersten Kunststofffolien-Lage in eine Fertigungseinheit;
2. b. Zuführen einer zweiten Kunststofffolien-Lage in die Fertigungseinheit;
3. c. Zuführen von Fasermaterial in die Fertigungseinheit und Anordnen des Fasermaterials zwischen der ersten Kunststofffolien-Lage und der zweiten Kunststofffolien-Lage;
4. d. Verbinden des Fasermaterials mit der Kunststofffolie der ersten Kunststofffolien-Lage und der zweiten Kunststofffolien-Lage unter Einbringung von thermischer Energie und/oder unter Aufbringung von Druck.

According to a further embodiment of a method proposed by the invention, it can be provided that the following steps are carried out:

1. a. Feeding a first plastic film layer into a production unit;
2. b. Feeding a second plastic film layer into the production unit;
3. c. Feeding fiber material into the production unit and arranging the fiber material between the first plastic film layer and the second plastic film layer;
4. d. Connecting the fiber material to the plastic film of the first plastic film layer and the second plastic film layer with the introduction of thermal energy and / or with the application of pressure.

If work is not to take place in a batch process, but in a continuous production of the composite material, continuous feeding of the plastic film layers and the fiber material into the production unit can be advantageous. For this purpose, the lower plastic film layer can be fed to the production unit via a lower feed unit, such as a roller arrangement or guide rails. This type of feed unit can also be used for the upper layer of plastic film. The connection process itself takes place under the action of thermal energy and / or pressure. For this purpose, for example, an arrangement of rollers is possible, between which the plastic film layers and the fiber material are subjected to pressure. Depending on the application, a multi-stage application of pressure using different roller or press arrangements makes sense. In addition to rollers and presses, other devices which can exert pressure are not excluded from the subject matter of the present invention. Thermal energy can be supplied by conduction, for example when it comes into contact with the rollers themselves, thermal radiation (for example infrared radiators or lasers), or by way of thermal convection (for example a heater fan). Other thermal sources are also conceivable here.

As already mentioned, the object on which the invention is based is also achieved by a material composite made of plastic and fiber material. The composite material can be produced by a method according to the invention.

According to the invention, the composite material is designed in the form of a layer structure, the fiber material being arranged between two plastic film layers and being connected to the plastic film of the plastic film layers.

According to one embodiment of a material composite proposed by the invention, it can be provided that the material composite is fiber-reinforced over its entire surface.

According to a further embodiment of a material composite proposed by the invention, it can be provided that the material composite is fiber-reinforced in partial areas, preferably such that the fiber-reinforced partial areas extend along a material composite axis and the material composite is alternately fiber-reinforced partial areas in a direction transverse to the material composite axis and non-fiber reinforced subregions.

• 1: eine Darstellung einer Ausführungsvariante des faserverstärkten Materialverbunds mit faserverstärkten und nicht-faserverstärkten Teilbereichen.
• 2: eine Darstellung eines Verfahrens zum Herstellen eines faserverstärkten Materialverbunds mittels oberer, unterer und mittlerer Zuführeinheiten.

Further features and advantages of the invention emerge from the following description of non-restrictive exemplary embodiments of the invention, which are explained in more detail below with reference to the drawings. These drawings show schematically:

• 1 : a representation of an embodiment variant of the fiber-reinforced material composite with fiber-reinforced and non-fiber-reinforced partial areas.
• 2 : an illustration of a method for producing a fiber-reinforced material composite by means of upper, lower and middle feed units.

the 1 shows an example of a material composite as can be obtained by a method according to the invention.

Specifically, in the 1 a fiber-reinforced material composite 1 shown which fiber-reinforced sections 6th and non-fiber reinforced sections 6th having. The sub-areas 6th extend essentially parallel to the material composite axis 7th and are transverse to the material composite axis 7th spaced apart. A composite material 1 in this form can be produced continuously and cut to size for the respective application. The number of fiber-reinforced sections 6th can vary.

In the 2 a production unit is shown which is set up to use the (fiber-reinforced) material composite proposed according to the invention 1 to manufacture. For this purpose, the production unit is fed by a lower feed unit 11th a first layer of plastic film 4a fed and through an upper feed assembly 12th a second layer of plastic film 4b fed. The fiber material is the manufacturing unit in the form of a fiber layer 3 through a middle feed unit 13th fed. The feed units 11th , 12th , 13th are shown here schematically in the form of roles. These are partly for Conveying the materials driven and / or free-running. The layer system made of the layers of plastic film, layered on top of one another 4a , 4b and the fiber layer 3 is then at a source 17th thermal energy passed to the top and bottom plastic film layers 4a , 4b to heat and then under pressure with the fiber material of the fiber layer 3 connect to. The pressure is produced by two rollers 18th upset. After a cooling phase, the composite material 1 removed or processed further.

List of reference symbols

1

Composite material

3

Fiber layer

4a, 4b

Plastic film layer

6th

Sub-area

7th

Material composite axis

11th

lower feed unit

12th

upper feed unit

13th

middle feed unit

17th

Source of thermal energy

18th

roller

QUOTES INCLUDED IN THE DESCRIPTION

This list of the documents listed by the applicant was 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.

Patent literature cited

• EP 2165821 B1 [0002]

Claims (12)

Method for producing a fiber-reinforced material composite (1) which is formed from plastic and fiber material, characterized in that the material composite (1) is designed in the form of a layer structure, the fiber material for forming the layer structure between two plastic film layers (4a, 4b ) is arranged and connected to the plastic film of the respective plastic film layer (4a, 4b). Procedure according to Claim 1 , characterized in that the fiber material is connected to the plastic film by introducing thermal energy, the thermal energy being introduced to the effect that the temperature of the plastic film when the fiber material is connected to the plastic film is above its melting temperature. Method according to one of the Claims 1 or 2 , characterized in that the plastic film layers (4a, 4b) are formed by separate plastic films. Method according to one of the Claims 1 or 2 , characterized in that the plastic film layers (4a, 4b) are formed by one and the same plastic film, the plastic film being folded in a folding area in such a way that the plastic film provides two plastic film layers (4a, 4b). Method according to one of the Claims 1 until 4th , characterized in that the plastic film layers (4a, 4b) are connected to one another when the thermal energy is introduced. Method according to one of the Claims 1 until 5 , characterized in that the fiber material is connected to the plastic film of the plastic film layers (4a, 4b) with the application of pressure. Method according to one of the Claims 1 until 6th , characterized in that the fiber material comprises fibers, in particular unidirectionally oriented continuous fibers, which are oriented essentially in parallel. Method according to one of the Claims 1 until 7th , characterized in that only partial areas of the composite material (1) are fiber-reinforced, preferably in such a way that fiber material is only provided in partial areas (6) along a composite material axis (7) and thus alternating in a direction transverse to the composite material axis (7) Subregions (6) are fiber-reinforced and non-fiber-reinforced. Method according to one of the Claims 1 until 8th characterized by the following steps: a. Arranging a first plastic film layer (4a) on a carrier; b. Arranging fiber material on a surface of the first plastic film layer (4a) facing away from the carrier; c. Arranging a second plastic film layer (4b) on the fiber material; d. Connecting the fiber material to the first and second plastic film layers (4a, 4b) with the introduction of thermal energy and / or with the application of pressure. Method according to one of the Claims 1 until 8th characterized by the following steps: a. Feeding a first plastic film layer (4a) into a production unit; b. Feeding a second plastic film layer (4b) into the production unit; c. Feeding fiber material into the production unit and arranging the fiber material between the first plastic film layer (4a) and the second plastic film layer (4b); d. Connecting the fiber material to the plastic film of the first plastic film layer (4a) and the second plastic film layer (4b) with the introduction of thermal energy and / or with the application of pressure. Material composite (1) made of plastic and fiber material, characterized in that the material composite (1) is designed in the form of a layer structure, the fiber material being arranged between two plastic film layers (4a, 4b) and with the plastic film of the plastic film layers (4a, 4b) is connected. Material composite (1) according to Claim 11 , characterized in that the composite material (1) is fiber-reinforced over its entire surface.

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