DE102012007839A1 - Multilayer fiber plastic-composite component with a class-A-viewing surface provided with a transparent glass layer, comprises at least one fiber plastic layer made of a matrix resin, and a fiber material embedded with carbon fibers - Google Patents

Abstract

Multilayer fiber plastic-composite component (1) with at least one class-A-viewing surface, comprises at least one fiber plastic layer (3) made of a matrix resin, and a fiber material embedded with carbon fibers. The visible surface is provided with a transparent glass layer (2), which is connected with the fiber plastic layer by the matrix resin. An independent claim is also included for producing the fiber plastic-composite component, comprising (i) producing and forming a transparent glass sheet corresponding to a form of the viewing surface of the fiber-plastic composite component, (ii) inserting the formed glass sheet into a molding tool (4), (iii) applying the fiber material and an uncured resin matrix on the glass sheet, (iv) applying pressure and temperature to the molding tool and curing the matrix resin, thus connecting the glass sheet with the fiber plastic layer by the matrix resin and forming the fiber-plastic composite component with the fiber resin layer and the glass layer, and (v) demolding the fiber-plastic composite component after curing the matrix resin.

Description

The invention relates to a multi-layer composite fiber-reinforced plastic component which has at least one class A-trained visible surface, as well as the corresponding method for its production.

In order to continue the lightweight construction of motor vehicles, components of fiber-reinforced plastics are increasingly used in vehicle construction because of their good mechanical properties and their low weight. The visible side of the FRP components, also known as fiber-reinforced plastic composite components, is usually painted to enhance or color the surfaces. Since, due to the different shrinkage behavior of fibers and plastic, the surface of the components after production often exhibits an irregular texture, so-called fiber markings, the coating is often very complex, since the surfaces of the FRP component to be painted must first be prepared, whereby high Costs incurred. There are therefore efforts to produce FRP components already with paintable Class A surfaces at least on the visible side of the component.

Carbon fiber reinforced components (CFRP components) advantageously have mechanical properties that satisfy particularly high mechanical requirements. As a result, thin surface components of motor vehicles, such as automobile doors, roof parts, trunk lids or hoods in lightweight composite construction can be created. However, because of the irregular surface, the visible side must also be covered with a cover layer in order to obtain a Class A surface. Especially with CFRP components, it may be desirable to make the structure of the CFRP material appear optically, since this achieves a high-quality appearance of the component through the use of the high-performance material CFRP.

For these reasons, sometimes FRP components are manufactured, which are designed for design reasons only with decorative cover layers of CFRP material. The component is given the high-quality appearance by the CFK cover layer, while a supporting body of the component is made of a less expensive material than CFRP. In this case, the cover layer made of CFK is usually preformed and adhered to the support body of the component. Alternatively, CFRP prepregs, impregnated semi-finished fiber products, can be applied to the support body and cured.

Such a multi-layered composite component having a plurality of layers such as a load-bearing support layer and a decorative cover layer in carbon fiber optics is in DE 10 2009 006 130 B4 described. The cover layer of carbon fiber or carbon mixed fiber reinforced plastic is connected by means of an adhesive layer of an elastomer to the carrier layer of metal and / or fiber-reinforced plastic. Here, the carbon fibers or carbon mixed fibers of the cover layer are arranged in optically recognizable patterns or regularities on the surface and only serve to give the component a high-quality appearance and contribute due to the reduced thickness of the cover layer only a minor part of the load-bearing function of the entire surface component. The aim of this mixed construction is to limit the proportion of CFRP for cost reasons as much as possible. In order to make the topcoat surface smooth and to obtain a Class-A visible surface, a thin transparent plastic or resin layer or clear coat may be provided over the carbon fiber or carbon composite fiber reinforced plastic layer. During production, the carrier layer, the elastomer material and the plastically deformable CFRP material are placed in a mold and joined together in a common pressing operation.

In general, for the creation of ready-decorated plastic components, the film back-molding (also film insert molding (FIM)) is known in which prior to the injection of the plastic melt in a Bauteilformkavität a preformed insert is inserted into the injection mold. The inserts are mostly printed films, which are then trimmed. Similarly, in the in-mold decoration (IMD) technique, a finished decorated member may be provided wherein a hot stamping foil is placed in a spiking die which is pressed against the wall of the cavity upon injection of the melt by the melt pressure. In this case, the lacquer layer of the hot stamping foil connects with the plastic due to the high melt temperature and dissolves after cooling from the polyester carrier foil.

In order to produce large-sized moldings with large surfaces, such as trunk covers or door elements, with the required mechanical properties in the automotive industry in a comparable surface quality, plastic films are also used, which are prefabricated in terms of texture and possibly coloring the surface of the component and preformed according to the component shape , These films are placed in a tool mold, so that on the side of the preformed film, which does not form the surface, a fiber-reinforced plastic can be applied after its curing or cooling, the finished molding of the mold can be removed. For applying the fiber reinforced Plastics can be used in processes such as film backpressing or film resin transfer molding (film RTM).

In film-backing pressing, the separately preformed film and a plate-like or matt-like fiber-plastic semi-finished product are arranged in a pressing tool and joined in a pressing process tailored to the composition of the semifinished fiber product.

For the film RTM process, preformed film and a fiber mat are placed in an injection mold, and after closing the mold and evacuating the mold cavity, a mixture of resin and hardener is injected into the mold cavity, thereby impregnating the fiber mat and filling the mold cavity , After curing of the resin, the tool is opened and the component can be removed.

Such a technique can also be used in open processes such as hand lamination or vacuum processes.

This also describes the DE 10 2008 009 438 A1 a method for the production of molded parts made of fiber-reinforced plastics with a refined visible surface, which have a surface film on the visible side. In this case, the surface film is shaped according to the topography of the molded part and a fiber material is applied to the inside of the molded surface film facing away from the visible surface. Subsequently, the impregnation is carried out with an uncured matrix material, whereupon the molding of the molding and curing takes place before the visible side of the surface film having molding is removed. This will be done in DE 10 2008 009 438 A1 a single mold is used in which the surface film is formed after cutting and heating to the softening temperature according to the topography of the molded part to be produced and the fiber and matrix material is applied to the inside of the surface film.

Based on this prior art, it is an object of the present invention to provide a lightweight plastic component with good mechanical characteristics and with a Class A surface.

This object is achieved by a composite component with the features of claim 1.

Another object is to provide a production process suitable for mass production, which is achieved by the method having the features of claim 5.

Further developments are set forth in the respective subclaims.

A multilayer composite fiber-reinforced plastic component according to the invention comprises one or more fiber-plastic layers, or FRP layers, of a fiber material embedded in a matrix plastic and consisting at least partly of carbon fibers. In this case, the fiber-plastic composite component has at least one class-A grade visible surface. This viewing surface is formed by a transparent glass layer, which is connected by the matrix plastic of the fiber plastic layer with the same. Thus, the cover layer formed by the glass layer does not comprise any fiber material, it is used for surface sealing and smoothing, while the load-bearing support body of the component is made of CFRP. An adhesive layer between cover layer and support body is not required here. The carbon fiber reinforced plastic layer forms the supporting body of the component, thus has a supporting function and requires no functional backing or the like.

The glass layer, for example, has the great advantage over polymeric films in that the roughness and unevenness of the surface of FRP materials due to the fibers does not appear on the visible surface. The outside, or upper side, of the glass layer remains completely uninfluenced by the FVK layer or FVK component arranged on the opposite inside side or lower side.

Advantageously, the composite component according to the invention offers a high cost advantage, since no transparent coating has to be retightened in order to produce a class A-capable visible surface. Without further measures, the transparent glass layer as a cover layer creates a carbon visible surface through the view of the underlying fiber layer. The glass also offers an integrated UV protection for the matrix plastic, which therefore has a longer service life. If safety glass is used as a glass layer, the material properties of the composite component are further improved.

The glass layer may consist of a mineral glass such as a silicate glass or a plastic glass. Plastic glasses may be made of polycarbonate, polymethyl methacrylate, polyvinyl chloride, polystyrene, polyphenol oxide, polyethylene or polyethylene terephthalate glycol.

Furthermore, the matrix plastic of the fiber plastic layer with respect to mechanical and physical properties such. B. the thermal expansion behavior can be matched to the material of the glass layer.

Even if the fiber-plastic composite component already has a finished visible surface with the glass layer, a lacquer layer may be provided on the side facing away from the fiber plastic layer side of the glass layer, such as a topcoat layer for decorative design in body color or a clearcoat to increase the scratch resistance. Furthermore, the glass layer can be colored for optical design. Means and measures for coloring glass sheets are known.

To produce a fiber-reinforced composite component according to the invention, a glass sheet is "back-injected" or "back-pressed" in an RTM or press or SMC process. For this, the method first comprises producing and forming a transparent glass pane in accordance with a shape progression of the visible surface of the fiber-reinforced plastic composite component. This shaped glass sheet is placed in a mold adapted for the respective process, and fiber material and uncured matrix plastic are applied to the glass sheet, so that this by applying pressure and applying the curing temperature of the matrix plastic, the bonding of the fiber plastic layer to the glass sheet produces, wherein the fiber-plastic composite component is formed. After curing of the matrix plastic, the fiber-plastic composite component can be removed from the mold.

With the method according to the invention, CFRP composite components with a Class A surface can be produced in a one-step process with quantities typical for automobiles.

When mineral glass is used for the glass sheet, the manufacturing and shaping of the transparent glass sheet may be carried out by the float method, a down-drawing method such as an overflow fusion method, casting and / or drawing, while the production and shaping of the transparent glass sheet is made of plastic glass Extrusion / extrusion, thermoforming, high pressure forming and / or a casting process such as injection molding may include.

Depending on the method used or the type of fiber material used, the application of the fiber material and the uncured matrix plastic to the glass pane may include laying at least one dry or preimpregnated, unformed or preformed fiber layer and injecting the uncured matrix plastic into the closed mold or placing at least one comprising impregnated with the uncured matrix plastic, unformed or preformed fiber layer.

Finally, if desired, the application of a lacquer layer, comprising a clear lacquer layer and / or a top lacquer layer, can take place on the glass layer.

These and other advantages are set forth by the following description with reference to the accompanying figures. The reference to the figures in the description is to aid in the description and understanding of the subject matter. The figures are merely a schematic representation of an embodiment of the invention.

Showing:

1 a side sectional view of the mold when inserting the glass and the fiber layer

2 a side sectional view of the mold during injection of the matrix plastic and

3 a side sectional view of the finished composite component.

The invention relates to a composite material for a lightweight component having a Class A surface or a visible carbon surface. The lightweight component is in particular a motor vehicle component, more particularly a flat body component, such as doors, roof segments, boot lid or hoods.

The plastic lightweight component according to the invention has a glass surface as a visible surface. Thereby, if desired, the fiber structure can be visibly displayed. Especially with the carbon fibers used, this visible representation, if present in a visually pleasing manner, for example as a braid, knitted fabric, knitted fabric, fabric, etc., desirable because the high-quality lightweight material used is immediately obvious. Carbon-look components characterize the prestige lightweight construction. If, unlike in the prior art, where only this look is to be achieved, the load-bearing support function is taken over by the carbon fibers, the components achieve not only optics but also very good mechanical characteristics. The manufacturing process allows automobiltypische quantities. Providing a Class A surface as the part is manufactured eliminates the need for surface preparation and painting steps, resulting in a significant cost reduction.

As an alternative to using pure carbon fibers, fiber mixtures can also be used. It can be different Reinforcing fibers, such as carbon and aramid fibers, but also mixtures of reinforcing fibers and other fibers, such as carbon fibers and natural fibers used. The other fibers in particular have the effect of producing special optical effects in the FRP component.

The production involves the pressing of a complete arrangement of fiber layer and glass layer in a one-step process. The fact that a previously shaped and cured transparent glass pane is used to form the glass layer avoids the wavy surface of the composite component resulting from physical and process-related conditions. In the process, a visible carbon fiber surface is created that does not have to be repainted. If a coating is still desired, such as when the fibers are optically less attractive, for. B. undirected mat or nonwoven, it can be applied without consuming measures on the glass surface, which has a Class A quality.

1 shows the insertion of the preformed glass 2 and the fiber layer 3 ' in the pressing tool 4 . 5 , Contrary to what is shown, the multilayer composite component can also be constructed from more than one fiber layer and more than one glass pane. The fibrous layer (s) may be a fluffy, pliable fabric which may optionally be preimpregnated dry or wet, but it may also be a consolidated preform whose fibrous material comprises a suitable binder to maintain the predetermined shape. If desired, a preform may also be preimpregnated with a powdery or liquid matrix material. Another alternatively usable fiber material is a semi-finished fiber already comprising the matrix plastic, z. B. in thermoset matrix prepregs or SMCs. In prepregs are continuous fibers, usually as a clutch or fabric, etc., while it is SMCs plate-like dough-like compounds, mainly with short fibers in mat form. Thermoplastic fiber semi-finished products according to the invention for the formation of the fiber layer 3 can be used are so-called organo sheets, which can be deformed by heating.

If a preconsolidated fiber material is used, the fiber layer (s) 3 ' before placing on the glass 2 ' preformed, pliable fiber materials are suitably on the glass 2 ' draped.

Depending on the fiber material used, two process variants are now conceivable: for dry or only preimpregnated fiber layers 3 ' or preforms is the RTM process and in finished impregnated fiber semi-finished products, the compression molding is performed to the bond between the glass sheet 2 ' and the fiber layer 3 ' to create through the matrix plastic.

2 shows the variant with the injection i of a matrix plastic in the of the tool halves 4 . 5 limited mold cavity to the fiber layer 3 ' to penetrate and to the glass 2 ' to get. Depending on the type of matrix plastic used, whether thermoplastic or thermosetting be in the tool 4 . 5 Curing conditions created. In the case of thermosetting matrix plastics, for example, this is heating up to a hardening temperature before cooling to remove the component. When a thermoplastic melt is injected as matrix plastic, the curing conditions require the mold to cool.

In addition to the mentioned RTM method, various injection methods such as vacuum injection method or resin infusion method can be used according to the invention, in which a matrix plastic is injected into the fiber material for its impregnation.

If a finished impregnated semi-finished used, eliminates the injection of matrix plastic. As a molding tool, a pressing tool is used, for. Example, a hot press, in which the shaping, curing of the matrix plastic and production of the composite with the glass is done. Again, the conditions differ depending on the matrix plastic used. Each matrix system requires defined temperatures for curing.

After curing, the finished component 1 represented in 3 , which are taken with the glass sheet side 2 provides a Class A surface that can be painted or unpainted on the visible surface the fiber layer 3 visible, if it is about a carbon braid, etc.

As material for the glass layer 2 Both mineral glasses such as silicate glass and plastic glasses such as polycarbonate or PMMA come into question. Other suitable transparent plastics are polyvinyl chloride (PVC), polystyrene, polyphenol oxide, polyethylene or polyethylene terephthalate glycol (PET-G).

The glass layer may also consist of a plurality of glass panes, it may in particular be a composite safety glass layer, which consists of two or more bonded or bonded discs, which may be made of non-tempered discs as well as combined biased discs. But it can also be a safety glass layer of a slice of thermally toughened glass. The bias arises while in the float glass particularly intensive cooling of the red-hot glass by means of air nozzles blowing on both sides during cooling to room temperature.

Optionally, the transparent glass layer may also be a colored glass layer.

The matrix plastic can be matched to the glass material used, matrix plastic and glass material can be tuned, for example, in terms of their thermal expansion behavior. As matrix plastics for the CFRP layer thermosetting plastics can be used, as they are known from the technology of CFRP processing, and the use of elastomers is conceivable. Further plastics suitable as a matrix are, for example, thermoplastics such as polycarbonate and PMMA, and furthermore a robust, weather-resistant material such as polyamide can be chosen as matrix plastic.

With the glass layer, the CFRP component produced in SMC or RTM process can be given a Class A surface, which otherwise can not be produced with these methods, or can only be produced to a limited extent, or require post-processing.

The carbon fibers, possibly also carbon blended fibers are usually present as fiber bundles, which are processed into a textile structure. Coal-blended fibers also include other reinforcing fibers in addition to carbon fibers, by means of which the visual appearance can be varied in terms of coloring. Here, the other reinforcing fibers can be mixed within a bundle with carbon fibers, but it can also be used different bundles, ie carbon fiber bundles and other reinforcing fiber bundles. The reinforcing fibers optionally used in addition to the carbon fibers may be aramid fibers, mineral fibers such as glass fibers or basalt fibers, metal fibers, polymer fibers or natural fibers.

Textile structures suitable for visible appearance on the surface have recognizable patterns or regularities, such as woven, knitted, knitted, braided, scrim, etc.

The composite component according to the invention may preferably be a surface component of a motor vehicle, for. B. to doors, flaps or roof segments.

Optionally, the glass layer may be provided with a lacquer layer, for. As a transparent clearcoat layer to increase the scratch resistance, and / or with a colored topcoat layer, if the fiber layer is not visible visible.

Another advantage of the method is that the component can not only be produced in a single process step, but that even complex geometries can be easily reproduced by this method.

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 patent literature

• DE 102009006130 B4 [0005]
• DE 102008009438 A1 [0011, 0011]

Claims (8)

Multilayer fiber-reinforced plastic composite component ( 1 ) having at least one Class A visible surface, comprising at least one fiber plastic layer ( 3 ) of a matrix plastic, in the fiber material ( 3 ' ), which has carbon fibers, is embedded, characterized in that the visible surface through a transparent glass layer ( 2 ) provided by the matrix plastic of the fibrous plastic layer ( 3 ) with the fiber plastic layer ( 3 ) connected is. Fiber-reinforced plastic composite component ( 1 ) according to claim 1, characterized in that the glass layer ( 2 ) of mineral glass, preferably silicate glass, or of plastic glass from the group comprising polycarbonate, polymethyl methacrylate, polyvinyl chloride, polystyrene, polyphenol oxide, polyethylene or polyethylene terephthalate glycol (PETG). Fiber-reinforced plastic composite component ( 1 ) according to claim 1 or 2, characterized in that the matrix plastic of the fiber-plastic layer ( 3 ) with respect to mechanical and physical properties to the material of the glass layer ( 2 ) is tuned. Fiber-reinforced plastic composite component ( 1 ) according to at least one of claims 1 to 3, characterized in that on the of the fiber plastic layer ( 3 ) facing away from the glass layer ( 2 ) a lacquer layer is present and / or the glass layer ( 2 ) is colored Process for producing a fiber-reinforced plastic composite component ( 1 ) according to at least one of claims 1 to 4, comprising the steps - producing and forming a transparent glass pane ( 2 ' ) according to a shape curve of the visible surface of the fiber-reinforced plastic composite component ( 1 ), - inserting the shaped glass pane ( 2 ' ) in a mold ( 4 . 5 ), - on the glass pane ( 2 ' ) Application of the fiber material ( 3 ' ) and the uncured matrix plastic, - Pressure and Temperaturbeaufschlagen the mold ( 4 . 5 ) and curing of the matrix plastic, thereby joining the glass sheet ( 2 ' ) with the fiber plastic layer ( 3 ) by the matrix plastic and molding of the fiber-reinforced plastic composite component ( 1 ) with the fiber plastic layer ( 3 ) and the glass layer ( 2 ), - after curing of the matrix plastic demolding of the fiber-reinforced plastic composite component ( 1 ). Method according to claim 5, wherein - producing and forming a transparent glass pane ( 2 mineral glass comprises the float process, a down-draw process comprising the overflow fusion process, casting and / or drawing, and - making and forming a transparent glass sheet ( 2 ) of plastic glass extruding / extruding, the thermoforming high pressure forming and / or a casting process, preferably injection molding. Method according to claim 5 or 6, wherein the application of the fiber material ( 3 ' ) and the uncured matrix plastic on the glass pane ( 2 ' ) - the application of at least one dry or preimpregnated, unformed or preformed fiber layer ( 3 ' ) and injecting the uncured matrix plastic into the closed mold ( 4 . 5 ) or - the application of at least one impregnated with the uncured matrix plastic, unformed or preformed fiber layer comprises. Method according to at least one of claims 5 to 7, comprising the step of - applying a lacquer layer, comprising a clear lacquer layer and / or a topcoat layer, onto the glass layer ( 2 ).

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