DE102006040748A1 - Production of fiber-reinforced thermoplastic car components by injection molding comprises forming armature from hybrid yarn containing thermoplastic reinforcing fibers and heating near melting point of thermoplastic fibers before molding - Google Patents

Abstract

Production of interior or exterior fiber-reinforced thermoplastic components for automobiles by injection molding comprises: (A) forming a non-consolidated textile or structural armature (1) from hybrid yarn composed of thermoplastic and organic or inorganic reinforcing fibers; (B) heating the armature, at least at its edges, to a temperature near the melting point of the thermoplastic fibers before or when it is placed in a mold; (C) injecting thermoplastic at a temperature above the melting point of the fibers; and (D) cooling and removing the molding.

Description

The The invention relates to a method for producing exterior or interior parts of motor vehicles made of fiber-reinforced thermoplastics, using a non-consolidated textile inlay Hybrid yarn by injection molding according to claim 1.

The The invention relates in particular to front ends, bumpers, trim parts and hat racks of automobiles made of fiber-reinforced plastics (FRP), which available by injection molding are.

such Components are common Assemblies of sheet metal parts. You have to work in several steps to be assembled. The tooling costs for the production of the sheet as a deep-drawn part are high and are particularly effective in small quantities out. For example, frontends and hat racks can be also be produced as FRP structures in press technology / extrusion technology. However, this involves several process steps and reworks necessary. The realizable geometries and their manufacturing tolerances are very limited and there are disadvantages in the stiffness, the acoustic properties and the manufacturing costs. Furthermore, there are no satisfactory joining methods for the Installation in the body or in the bodyshell structure of motor vehicles.

When further requirement for such interior or exterior parts, in particular trim parts, such as a door trim or a parcel shelf there is a desire for material composites. In this case, a lining part is to be provided which in different Areas different functionalities, in particular a gain function and a design function such as surface finish or shape complexity having. The amplification function can be in particular by reinforcing fibers realize.

From the DE 295 03 709 U1 For example, a plastic lining element is known for the interior area of vehicles with a visible and rear side, which in at least two areas consists of at least two materials which are different in type, color, hardness, strength and / or surface finish and surface decoration. For this purpose, plastic is formed on at least one edge termination of a preformed part, which may be both a dimensionally stable as well as a non-dimensionally stable in itself part at its rear region.

From the DE 199 22 799 A1 is an RTM method and a suitable apparatus for producing fiber-reinforced composite materials known. In particular, draping tools are executed which prevent warping or displacement when lowering the positive punch of the draping tool by means of geometrically adapted clamping frames for the fiber web. The matrix material is supplied in the usual way molten via dosing.

A pulltrusion process for the production of fiber reinforced plastic products with long or continuous fiber reinforcement is out DE 197 56 126 C2 known. Here, a hybrid band of finely long reinforcing fibers and thermoplastic matrix fibers is first produced as their carrier material. Thereafter, at least one strip is introduced into a screw machine, so that a plastically deformable long-fiber molding material is formed by melting the thermoplastic matrix fibers. By this method, long fiber reinforced plastic products can be produced by plasticizing hybrid fiber slivers on screw machines.

Become frequent applied for the production of FRP also injection molding. These but have the disadvantage that sometimes only an unsatisfactory complete Embedding the reinforcing fibers reach into the matrix and the fiber lengths in the Component are very different. Especially in demanding Geometries is a complete or even flow around the reinforcing fibers difficult to reach. This is especially true for components with changing areas with fiber reinforcement and without fiber reinforcement. adequately dimensionally stable fiber structures made of reinforcing fibers can be in usually only reach when very high fiber densities present in the fiber structure, which is the complete flow around the reinforcing fibers with special needs.

It It is therefore an object of the invention to provide a method, with the fiber-reinforced exterior or interior parts of motor vehicles of complex geometries or alternately reinforced and unreinforced Make areas in a simple manner and inexpensively.

• – Herstellung mindestens eines nicht konsolidierten Textileinlegers aus Hybridgarn aus thermoplastischen und aus (an)organischen Verstärkungsfasern,
• – Vorwärmen des mindestens einen Textileinlegers auf eine Temperatur nahe dem Schmelzpunkt der thermoplastischen Fasern,
• – Einbringen des mindestens einen Textileinlegers in eine Spritzgießform
• – Umspritzen des mindestens einen Textileinlegers mit einem thermoplastischen Matrixpolymer bei einer Temperatur oberhalb der Schmelztemperatur der thermoplastischen Fasern, wobei diese im wesentlichen vollständig aufgeschmolzen werden und
• – Abkühlung und Entnahme des Exterieur- oder Interieurteils, mit den Merkmalen des Anspruchs 1.

The object is achieved by a method for producing exterior or interior parts of motor vehicles made of fiber-reinforced thermoplastics with the steps

• Manufacture of at least one unconsolidated textile insert of hybrid yarn of thermoplastic and of (inorganic) organic reinforcing fibers,
• Preheating the at least one textile inlay to a temperature close to the melting point of the thermoplastic fibers,
• - Introducing the at least one textile insert in an injection mold
• - Overmolding the at least one textile insert with a thermoplastic matrix polymer at a temperature above the melting temperature of the thermoplastic fibers, wherein these are substantially completely melted and
• - Cooling and removal of the exterior or Interieurteils, with the features of claim 1.

Under (on) organic reinforcing fibers are to understand organic or inorganic fibers, which among the Conditions of manufacture are infusible and, in particular, as long-term or continuous fibers are used. The (on) organic fibers be used with or without sizing. Preferably wear the (An) organic fibers, a size of thermoplastic polymer.

The Temperature is near the melting point of the thermoplastic fibers prefers a narrow temperature window below the softening temperature.

By The benefits of the injection molding process give great freedom in shaping the shape of the component, high component accuracy and the composite component can be manufactured in only one process step.

By the use of a non-consolidated textile insert made of hybrid yarn Is it possible also by injection molding fiber-reinforced plastic lightweight components high production quality, produce at low part costs. Compared to the common methods is the inventive particular for small to medium quantities economically.

For the invention It is essential that hybrid yarns, or hybrid multi-twist yarns be used. These include, in particular, hybrid commingling yarns to understand which z. B. by air texturing entangled filament yarns from reinforcing and thermoplastic filaments. Also covered here are braided hybrid yarns braided yarn of reinforcing and thermoplastic rovings or hybrid worsted yarns made by the worsted spinning process made of reinforcing fibers and thermoplastic fibers available as well as parallel hybrid yarns or smooth filament yarns, the parallel reinforcing and Thermoplastic filaments exist.

The Textile inserts are textile, two- or three-dimensional fabrics from the hybrid yarns or dry prepregs made from them with textile character. In general, the textile inlaid as contour-compatible textile semi-finished products or textile preforms used.

The Textile inserts are preferably conformal as knitted fabrics or knitted fabrics made of hybrid yarn. These are distinguished through a high drapability and contribute to the structural integrity.

A further preferred embodiment of the textile insert sees 2D hybrid structures, So two-dimensional textile surfaces from reinforcing and thermoplastic fibers, wherein the orientation of the reinforcing fibers only in two directions, i. there is no third direction of reinforcement that oriented perpendicular thereto.

A Another embodiment provides 3D hybrid structures. The orientation the reinforcing fibers takes place in the plane and in addition in the third dimension (z-direction), for example, vertical is oriented to it.

Become textile fabrics, for example, flat Knits, woven or knitted fabrics or 2D hybrid structures used, so they are preferably deformed by draping around to a 3-dimensional Textile inlaid to arrive. As a result, textile surface formation or confectioning process, spatially contoured textile Semi-finished products, or textile inlays produced.

In Preferred embodiment, the textile inserts are designed so that I'm doing a near net shape preforming process, respectively the final contour of the injection-molded exterior or interior parts essentially corresponds to the shape of the textile insert.

According to the method is provided a preheat the at least one textile inlay to a temperature close to the Melting point of the thermoplastic fibers before the injection molding process performed becomes. It must at least the edge zone of the insert are brought to this temperature. This is a far completely complete melting and Umfließenden the reinforcing fibers reachable. The warming can outside or inside the injection mold. If necessary, the To heat injection mold at least one side. The preheating temperature May vary depending on the thermoplastic, especially depending on the sharpness of the Melting point, down to a few ° C be selected below the melting temperature. Are useful Areas from 5 to 50 ° below this Melting temperature, or the glass transition temperature, at least in the marginal zones of the yarn or twine.

The textile inlay can be used to reinforce the reinforcement or improve the connection to the matrix locally Have breakthroughs, edges and beads.

In Another preferred embodiment of the textile insert has this Inserts on which are incorporated in the textile. Prefers These algae consist of fasteners or recordings of connecting elements of the component to be formed. This can be, for example Pods, bolts or threaded parts, for example made of metal, plastic or reinforcing fiber fabric are formed. These are preferably formed from metal and serve as a connection to metallic body parts. Also hinges or edge depositor can serve as deposits. These deposits are only partially encapsulated or protrude partly over a large area the injection molded part out.

such Hybrid connection sockets allow mounting in the body shell with common joining methods, like enforce joining or sticking. Preference is given to a KTL coating before assembly (Cathodic dip painting).

A Particularly preferred embodiment of the exterior or interior parts provides a subdivision into structural and functional areas. The structural region is that by (an) organic fibers, in particular Continuous fibers reinforced Area and the functional area an unreinforced, i. not by long fibers reinforced Area. In the injection molding of the components, a textile insert is selected, the only the portion of the injection mold intended as a structural area fills. Optionally, the textile inserter is at least on one side of the To fix injection molding tool to a floating or slipping to prevent during injection molding.

In The simplest embodiment of the functional area is only to the unreinforced Thermoplastics with a smooth surface. Further embodiments are profiled surfaces or molded functional parts, such as handles, or fasteners made of thermoplastic. To the Functional areas can also by ribs, or beads self-reinforced planar structures include.

A another variant provides that the structural area over the Functional area protrudes. In this case, the protruding parts of the fiber-reinforced structure in particular as connecting or fastening elements with others Parts of the vehicle body serve. The exterior or interior judgment can hereby be a rod-shaped, band-shaped, strut-shaped, strand-like, flat or sheet-like component or even complex 3-dimensional structural part in which the structural area on the sides, edges and / or over the ends projects beyond the functional area.

When Fiber types are organic in terms of reinforcing fibers Continuous fibers Polyamide fibers, glass fibers, C fibers, natural fibers and / or aramid fibers particularly preferred. As organic natural fibers are in particular Cotton fibers, cellulose fibers, abaca fibers or hemp fibers suitable.

When continuous thermoplastic fibers are in particular PEEK fibers (polyetheretherketone), PA fibers (Polyamide), PE fibers (polyethylene) and / or PP fibers (polypropylene) suitable.

When Thermoplastic for encapsulation or as plastic matrix for the Component are in particular PEEK, PA, PE and / or PP suitable. For high performance applications can also be used polyetherimide or polyethersulfone.

In Another variant will be for the plastic matrix filled used thermoplastic polymers. Here are in particular with Short glass fibers, or nanofillers filled Thermoplastics of importance. For example, PP is with nanodisperse alumina suitable.

Prefers is used as thermoplastic fiber in the reinforcing yarn, hybrid yarn or Hybrid Zweierewirngangan and as matrix polymer of the same type of polymer selected. The injection molding temperature is usually above the melting temperature of the fiber polymer, so that a complete melting of the same kind favored thermoplastic fibers becomes. Preferably, the injection molding temperature is adjusted so that softening and melting at least in the edge zone of the hybrid yarn he follows.

Within The hybrid yarn will be the distribution of thermoplastic to reinforcing fiber preferably chosen that the amplified Areas a gain fiber content from 40 to 65% by volume.

The Verstärkuzungsfasern. In particular, glass or carbon fibers preferably carry one Sizing, which improves the adhesion in the polymer matrix. In In a particularly preferred embodiment, the sizing is off the polymer forming the plastic matrix is formed.

In the 1 to 5 Examples of preferred embodiments of the invention are shown.

there demonstrate:

1 the components of a frontend carrier with FVK structural insert ( 1 ) and plastic matrix ( 4 )

2 a textile inlay ( 1 ) with recesses ( 5 )

3 a cross bridge between headlamps with functional area ( 4 ), Structural Inlay ( 1 ), Structure area ( 3 ) and connecting element ( 6 )

4 a section of a cross bridge between headlamps with functional area ( 4 ), Structural Inlay ( 1 ) and connecting element ( 6 )

5 the structural insert for a parcel shelf with connecting elements ( 6 ), Breakthroughs ( 7 ) and depressions ( 9 )

1 shows the individual components of a frontend carrier for passenger cars. First, a structural insert ( 1 ) of hybrid yarn, thereby forming a FRP structural insert. The structural insert is completely covered with plastic matrix ( 4 ), which determines the outer shape of the component.

2 shows a draped, unconsolidated, biaxially reinforced multilayer knit, in flat knitting technique.

3 shows a cross-bridge, which can be introduced between headlights of passenger cars. The functional area ( 4 ) made of plastic matrix has rib-like structures, as they are typical for lightweight construction. In the structural area a fiber reinforcement is provided, which through the structural insert ( 1 ) is made of hybrid yarn. In the fiber-reinforced area cast-in connecting elements ( 6 ) intended. These consist of sleeves woven by carbon fibers.

4 shows the section of a cross bridge. The structure inserter ( 1 ) projects beyond the longitudinal axis of the component from the plastic matrix ( 4 ) or the functional area. The structure insert is only partially completely surrounded by matrix. The component contains a sleeve-shaped connecting element ( 6 ), which protrudes through functional and structural area.

5 shows the structural insert for a parcel shelf of a passenger car. In the vicinity of the edges connecting bushes are arranged, which by inserted connecting elements ( 6 ) are formed. The structure insert has breakthroughs ( 7 ) remain unreinforced in the later component. The structural insert is three-dimensional and has recesses ( 9 ) on.

Claims (15)

Method for producing exterior or interior parts of motor vehicles made of fiber-reinforced thermoplastics by injection molding, comprising the steps of producing at least one non-consolidated textile or structural insert ( 1 ) of hybrid yarn of thermoplastic and of (inorganic) organic reinforcing fibers, - preheating the at least one textile inlay ( 1 ) at least in the edge zone to a temperature close to the melting point of the thermoplastic fibers before or during the introduction of the at least one textile or structural inserter (US Pat. 1 ) in an injection mold - molding the at least one textile or structural insert with a thermoplastic at a temperature above the melting temperature of the thermoplastic fibers, which are melted at least in the edge zone of the textile or structural insert - cooling and removal of the exterior or Interieurteils. Method according to claim 1, characterized in that an exterior or interior judgment is made with a structure area reinforced by (continuous) organic continuous reinforcing fibers ( 3 ) and a non-continuous fiber-reinforced functional area ( 4 ) is formed. Method according to claim 1 or 2, characterized that a thermoplastic filled with short fibers or nanofillers as thermoplastics chosen becomes. Method according to claim 2, characterized in that that filled with short-glass fibers Thermoplastic chosen becomes. Method according to one of the preceding claims, characterized in that during injection molding in the structural area ( 3 ) Recesses ( 5 ) for receiving fasteners ( 6 ) are formed. Method according to one of the preceding claims, characterized in that in the structural area ( 3 ) Connecting elements ( 6 ) are introduced and poured during injection molding. Method according to claim 6, characterized in that as connecting elements ( 6 ) Inserts are used in the form of metal bushings or bolts. Method according to one of the preceding claims, characterized in that as a textile insert ( 1 ) single-layer and biaxial reinforced multi-layer flat knit, or 2 or 3-dimensional knitted fabrics, knitted or woven fabrics are used. Method according to one of the preceding claims, characterized in that textile inserts ( 1 ), which have breakthroughs, edges and beads in the textile. Method according to one of the preceding claims, characterized characterized in that a hybrid yarn of more than 2 different Fiber types selected becomes. Method according to one of the preceding claims, characterized in that polyamide fibers, glass fibers, C fibers, natural fibers and / or aramid fibers are used. Method according to one of the preceding claims, characterized characterized in that the (on) organic reinforcing fibers from a sizing wear the thermoplastic of Matrixthermoplasten. Method according to one of the preceding claims, characterized characterized in that as thermoplastic continuous fibers PEEK fibers, PA, PE fibers and / or PP fibers are used. Method according to one of the preceding claims, characterized characterized in that used as thermoplastics PEEK, PE and / or PP become. Method according to one of the preceding claims, characterized in that the textile insert ( 1 ) is overmolded with the same thermoplastic as in the hybrid yarn.