EP3227484A1

EP3227484A1 - Textile semi-finished product

Info

Publication number: EP3227484A1
Application number: EP15808128.1A
Authority: EP
Inventors: Norbert Brunk; Roy GLUTHMANN; Egon Gründig
Original assignee: Hermes Schleifkoerper GmbH and Co KG
Current assignee: Hermes Schleifmittel GmbH and Co KG
Priority date: 2014-12-03
Filing date: 2015-12-02
Publication date: 2017-10-11
Also published as: WO2016087503A1; CN107208334A

Abstract

The invention relates to a textile semi-finished product comprising at least one reinforcing layer, which has substantially drawn individual yarns or yarn sheets (2, 4, 6), and at least one stitch-forming connecting yarn (1), which holds individual yarns or yarn sheets. According to the invention, the semi-finished product comprises at least one thermoplastic matrix yarn (3) which is fixed by stitches of the connecting yarn (1) and diverted thereon.

Description

Textile semi-finished product

The invention relates to a textile semi-finished product, with at least one reinforcing layer, which stretched substantially ver ^¬ current, as a standing threads and / or as a full shot (parallel shot) formed filaments or groups of filaments, and in holding at least one individual threads or thread groups connecting thread, the mesh forms.

Such products are required for the production of thermoplastic fiber composite structures, which are produced by pressing under the influence of temperature. Thereby melting the thermoplastic matrix component and combines with the United ^¬ reinforcement layers to a high-strength composite material. Thus, the production of complex, multi-dimensionally shaped components of high strength and impact resistance is possible. This manufacturing process is used for a large number of industrial parts produced in large series, in particular for those in shipbuilding, aircraft construction and vehicle construction.

In EP 0 361 796 A2, a moldable semi-finished textile product is described, wherein a plurality of superimposed

Layers are each formed of juxtaposed, not interwoven threads and in these layers, a matrix component is introduced. This may con- sist of thermoplastic ^¬ plastic or thermosetting resin, metal or ceramic and advertising introduced in the form of threads, tapes, sheet-like layers, woven or nonwoven materials the. Finally, the reinforcing layers and the matrix components are sewn together.

DE 10 2008 063 545 A1 discloses a multiaxial fabric consisting of several layers of fiber strands. These run in a straight line and parallel to each other and have a different orientation in each position. The fiber strands can consist of reinforcing fibers or thermoplastic threads or of mixtures of the same and are connected to one another by thermoplastic connecting threads. Because the thermoplastic tie yarns are made of the same material as the matrix precursor component, they both melt into a unitary composite material. Thus, the fiber composite material produced in the ^¬ se ne contains by no more connecting threads.

In DE 10 2012 007631 Al it is proposed to establish a textile multilayer reinforcing structure with integrated thermoplastic matrix such that when a Multiaxialge- put between unidirectionally aligned reinforcing ^¬ layers thermoplastic fiber material in the form of Faserv ^¬ read is placed. The layers of the reinforcing threads as well as the nonwoven fabrics are finally fixed by connecting threads.

The invention is based on the object to provide a semi-textile ^¬ zeug of the type mentioned, from which can be produced composite structures with high strength and defined properties.

This object is achieved in that at least one thermo ^¬ plastic matrix thread is provided which is fixed by stitches of the connecting thread and deflected thereto. First, some Be ^¬ handles used in the context of the invention will be explained. An inventive textile semi-finished product is a Halbfertigpro ^¬ domestic product, from which can be manufactured in a fiber composite workpiece or -Material under the action of pressure and / or temperature with melting thermoplastic constituents. The reinforcing layer gives the semifinished product and a workpiece produced therefrom strength, in particular tensile strength in the axial direction of the elongated individual threads or suture courses. These are stretched and can thus absorb high tensile forces. The semi-finished product according to the invention is thus not a woven fabric, but preferably a knitted fabric. The elongated monofilaments or filament bundles are inventively formed as standing threads and / or as a full shot (parallel shot) from ^¬ . The term Stehfaden is a technical term known from the terminology of warp knitting and refers to a linearly extending in the longitudinal direction, between two wales incorporated thread line without limitation by stitches or handles thereof. The term full shot or parallel shot refers in transverse or oblique direction duri ^¬ fende thread sections that are not limited by meshes of the same thread. As a full shot the thread line runs over the entire width of the knitted fabric. The design as a stationary thread and / or as a full shot (Parallel shot) allows this ^¬ A zelfäden or fiber sheets, as a reinforcing layer high Strengthens ^¬ te, in particular tensile forces to take.

A group of threads usually comprises a plurality of individual threads, which may be the same or different and may consist of different materials in order to a total of a plurality of characteristics embossed by the respective thread materials properties.

The connecting thread holds monofilaments or thread bundles and connects them. Holding means that the connection thread at least contributes to the threads in question are spatially fixed to each other or be ^¬ limited in their freedom of movement. The connecting thread pierces neither individual threads nor a group of threads and thus can not weaken their structure and strength. The connecting thread can in particular cover and / or wrap around threads and thus contribute to the holding function. The connecting thread can perform the holding function alone or in cooperation with other thread systems.

The connecting thread forms stitches. The basic textile structure of a semifinished product according to the invention is that of a warp knitted fabric. Warp knitted fabrics are familiar to the person skilled in the art and are preferably produced on so-called Raschel machines for this application.

The inventively provided matrix thread is thermoplas ^¬ table. The term thermoplastic is to be understood in the context of the invention as the property of a fabric or a thread material to melt in the course of further processing of the semifinished product under pressure and / or temperature to produce a composite. In this course, the matrix thread completely or partially loses its thread structure and merges into a matrix material that binds and / or embeds the reinforcing fibers. Suitable thermoplastic mate ^¬ materials preferably melt at temperatures between 150 and 300 ° C. Suitable are thermoplastic polymers such. As polyester, polyamide or polypropylene. These materials can be introduced in all usual in textile technology and suitable for processing filamentary designs. On the other hand, the reinforcing fibers or the filaments of the reinforcing layer do not melt under the processing conditions, or at most only to a small extent, substantially retain their shape and structure, thus causing the fiber reinforcement of the resulting fiber composite structure.

The thermoplastic matrix thread is fixed by stitches of the connecting thread and deflected there. This means that the matrix thread in the warp knit is defined positio ^¬ ned. The matrix thread can thus be selectively arranged so that it is at the desired location during melting and gives the desired effect, for example the defined and targeted embedding and / or bonding of two or more reinforcing layers arranged one above the other.

The described prior art has two significant disadvantages which the invention has recognized and remedied by the inventive structure of the semifinished product.

On the one hand, the state of the art is based on webs or nonwovens of reinforcing fibers, which are often unstable and materially inhomogeneous (for example with respect to the fiber density) and can lead to properties varying in properties in the finished product. Also, it may be problematic due to these fluctuations, the fibers largely largely and uniformly einzu ^¬ bind in a thermoplastic matrix component. Incompletely wetted or penetrated by the matrix component fibers often form defects and starting ^¬ points for structural breaks or cracks in the composite material. Secondly, in the prior art, the reinforcing fibers of connecting threads are needled or sewn, while a bundle of threads forming a unit in principle can be pierced and weakened in their structure. This weakens the strength of the resulting composite. May occur piercing it ^¬ follows in these methods irregular and not beinfluss- bar, so unpredictable and locally fluctuating Beeinträch ^¬ adjustments of the strength. The inventively provided structure of a warp knit (with or without weft insertion), in which the connecting threads form stitches, avoids due to the manufacturing principle certainly piercing v of individual threads or a group of threads and thus obtains their full structural strength. In knitting ensures that connecting threads always penetrate the plane of the reinforcing fibers or yarn sheets in the free spaces between the individual threads or thread groups, and this therefore not pierce or durchsto ^¬ chen.

The incorporation of thermoplastic matrix filaments, so that these are fixed by loops of thread compound thereto and vice ^¬ deflected causes a defined and uniform positioning of the arrangement and which melt the matrix material relative to the reinforcing layers and the fiber sheets. As a result, a homogeneous matrix can form during the melting, which ensures a reliable and complete covering of all reinforcing fibers or threads by means of short flow paths. According to the invention therefore a textile semi-finished product and from a fiber composite material having a defined, high and uniform ^¬ consistent quality and mechanical strength can be produced. In a first embodiment of the invention, the textile semifinished product has a reinforcing layer. This means that it has only stretched in a plane extending filaments or groups of filaments which are preferably substantially par- allel extend, forming a uniaxial structure which imparts be ^¬ sondere tensile strength in that direction. The Wenig ^¬ least a thermoplastic matrix is formed as a thread part shot in this exporting ^¬ approximately of the invention. In warp knit fabrics, a weft is a threadline extending in a transverse or oblique direction which is not bounded by stitches of the same thread. A partial shot is single ^¬ lich over part of the width of the knitted fabric. In a second embodiment of the invention, it is provided that it comprises a reinforcing layer and in addition to the at least one thermoplastic matrix thread has a second, substantially parallel to the threads of the reinforcing layer extending thermoplastic thread, wherein the thermoplastic matrix thread between the reinforcing layer and the second thermoplastic thread runs. By virtue of the second thermoplastic thread extending substantially parallel to the threads of the reinforcing layer, the proportion of thermoplastic material in the composite material obtainable from the semifinished product can be increased.

In a further embodiment of the invention, the textile semifinished product has at least two reinforcement layers which run in planes which are substantially parallel to one another. The filaments of these two reinforcing layers may be substantially parallel to each other when particularly high uniaxial strength in one direction is desired. In the ^¬ sem case, it may happen that the connecting thread that second reinforcing layer not fixed. It may then be ^¬ OF INVENTION dung provides that a second thermoplastic matrix filament is formed as a part shot on the outer side of this to fixie ^¬ Governing second reinforcing layer.

In general, however, it is preferred that the yarns from we ^¬ nigstens two of the reinforcement layers to one another enclose an angle, preferably substantially orthogonal to each other ^¬. In this way one obtains a biaxial structure with high strength in different directions.

It is particularly preferred if, in this embodiment, at least one thermoplastic matrix thread runs between two planes of reinforcing layers. This causes the two reinforcing layers do not rest directly on each other, but rather they each have contact with the matrix thread and can be particularly homogeneously incorporated into the matrix material during melting. At least one thermoplastic matrix ^¬ plastic thread can be inventively designed as part of income.

In a further preferred variant, at least one thermoplastic matrix thread is preferably guided predominantly through intersection regions of yarn bundles of the at least two reinforcing layers. This causes just takes place when Aufschmel ^¬ zen in these intersection regions a good connection and embedding of the threads into the matrix in the area of the important for the structural strength of crossing points. In a further embodiment of the invention, the connecting thread may also be formed thermoplastic and melt completely or partially in the course of further processing of the semifinished product into a composite workpiece. It can then be It can be seen that the melting temperatures of the thermoplastic matrix thread and the thermoplastic connecting thread differ from each other. In a first variant, the melting temperature of the thermoplastic compound yarn is less than that of the thermoplastic matrix ^¬ plastic thread. In this way, melting of the connecting thread can first be achieved with a corresponding temperature control, the thermoplastic matrix thread being retained in its shape. As a result, the composite of the yarn layer dissolves and the threads can in the sense of improved flexibility and adaptability to the

Move press mold. The melting of the thermoplastic matrix thread takes place at a higher temperature and the textile structure has significantly lower stresses at this point in time.

In a special geometry of the mold, it may be advantageous if the textile composite still exists during melting of the matrix component. In this case, a thermoplasti ^¬ shear connecting thread has to be chosen, the melting temperature exceeds the melting temperature of the matrix yarn.

According to the invention, the thermoplastic matrix thread between the mesh of the connecting thread partially rectilinear

and / or bend.

According to the invention it can be provided that the individual threads or bundles of threads contain fibers selected from the group consisting of glass fibers, carbon fibers, basalt fibers, high-strength polymer fibers and mixtures thereof. Preferably, the fibers or filament bundles are processed with commercially available textile machines. The invention further fiber composite workpieces or -Werkstoffe, obtainable by heating and forming a textile semi-finished product according to the invention.

As a result of their manufacture and construction, these workpieces have a materially and mechanically homogeneous structure and can be reliably reproduced. Random strength ^losses due to heavily or less heavily damaged reinforcement layers or variations in the thermoplastic matrix content can largely be ruled out.

Embodiments of the invention are explained below with reference to the drawing. Show:

Figures 1-3: Schematically the structure of three

textile semi-finished products according to the invention.

FIG. 1 shows a semifinished product according to the invention with two reinforcing layers arranged one above the other, namely warp threads and weft threads. These are formed from rectilinear and stretched, formed as standing threads 2 or as a full shot (parallel shot) 4 filaments or yarn sheets 2, 4. They are approximately orthogonal to each other and together form the reinforcing structure.

Their cohesion as a textile fabric is ensured by the connecting thread 1. The thermoplastic yarn 3 forms the thermoplastic matrix ^¬ component. He always runs between warp and weft thread, partially wraps around the stitches of the connecting thread 1 and is thereby fixed, but also deflected. Depending on machine NEN adjustment and choice of stitching, the course between the deflection points can be straight or curved, furthermore, the length between these points can be varied. Thereby, and by means of the choice of the fineness of the matrix thread, the proportion of matrix component can be varied and thus adapted to the requirements of the intended specific use.

Due to the design penetrate the connecting threads 1, the plane of the reinforcing fiber strands 2 and 4 always clear in the free-between the individual threads or thread groups, so that they are not damaged by piercing and performing the connection ^¬ thread.

The present embodiment forms a stable, largely distortion-free, consisting of exactly positioned textile elements multi-layer composite. It enables Drapie ^¬ ren in three-dimensional shapes and during the melting a good sliding of the reinforcement layers independently. For the production of a semifinished product according to the invention Raschelmaschinen are suitable with Magazinschusseinrichtung and at least 3 guide bars, wherein a guide bar forms stitches.

Known manufacturers of textile machinery include the compa- nies Karl Mayer Stitchbonding and Liba (currently Karl Mayer Liba Southwestern ^¬ tilmaschinenfabrik GmbH)

The product shown in FIG. 1 was produced on a Raschel machine with weft insertion RS2 (3) MSUN 150 "18E year 1993 of the company Karl Mayer Textilmaschinenfabrik GmbH.

Material components and machine parameters: Guide bar 1: knitting thread connecting thread

PP yarn 84 dtex

Laying: 0 1/2 -1 //

Moving in: full

Mesh density: 7.13 M / cm

Guide bar 2: reinforcement roving, textile glass 300 tex

Moving in: full

Guide bar 3: thermoplastic matrix thread, PP yarn 1100 dtex

Moving in: full

Weft: reinforcement roving, textile glass 300 tex

Moving in: full

Basis weight of the semi-finished textile product: approx. 642 g / m ²

By opposing LI (guide bar 1) to L3, the thermoplastic matrix thread (L3) is caught by the knitting line (LI) so as to be under 2 reinforcing rovings of the L2, covering a reinforcing roving in the weft per change of direction. A change of direction of the thermoplastic Ma ^¬ trixfadens (L3) is always after the completion of a mesh ^¬ row instead. Due to the arrangement of the guide bar L3 of the thermoplastic matrix thread is always placed between the reinforcement rovings ^¬ L2 and the shot Verstärkungsrovings.

The knitting thread of the guide bar LI (connecting thread) connects the reinforcement rovings (L2 and weft) and the thermoplastic matrix thread (L3) into a flat structure. Due to the selected machine and raw material parameters, a fiber volume fraction of the reinforcing fibers of approx. 40% can be achieved in the textile semi-finished product. A further preferred embodiment is shown in FIG. 2 Darge ^¬ represents. In comparison to the structure shown in FIG. 1, an additional thermoplastic thread is introduced in the warp direction 5. As a result, the proportion of thermoplastic material can be increased independently of the thermoplastic matrix thread 3 as part shot. The reinforcing fiber strand in the warp direction 2 runs approximately at right angles to the reinforcing fiber strand in the weft direction 4, wherein both fiber strands are fixed by the connecting thread 1 which is thermoplastic in this embodiment. Since the additional thermoplastic thread 5 is held by the thermoplastic matrix thread 3 between the reinforcing strand in the weft 4 and the reinforcing strand in the warp direction 2, a reliable penetration of the reinforcing layers with thermoplastic material is ensured at their crossing points.

In particular for applications with tensile loads in a preferred direction, a further embodiment may be appropriate. According to FIG. 3, a warp knit without weft ^{insertion is} used. Accordingly, the reinforcing components consist of the reinforcing fiber strand in the warp direction 2 and the further reinforcing fiber strand in the warp direction 6, in each case at different levels. Again, the thermoplastic yarn 3 extends as a matrix component Zvi ^¬ rule the reinforcing fiber strands. Because the thermoplastic connecting thread 1 does not fix the reinforcing fiber strand 6, another thermoplastic thread 7 is introduced as a partial weft.

Claims

claims

Textile semifinished product, comprising at least one reinforcing ^¬ layer, the substantially stretched running, as standing threads and / or as a full shot (parallel shot) out ^¬ formed monofilaments or yarn sheets (2, 4, 6), and with at least one monofilaments or yarn bundles retaining compound thread (1), forms the mesh, characterized in that at least one thermoplasti ^¬ shear matrix thread (3) is provided, which is fixed by loops of compound thread (1) and deflected it.

Textile semi-finished product according to claim 1, characterized in that it comprises a reinforcing layer and the Wenig ^¬ least a thermoplastic matrix filament (3) is formed as part of the net.

A semifinished textile product according to claim 1, characterized in that it comprises a reinforcing layer and in addition to the at least one thermoplastic matrix thread (3) has a second thermoplastic thread (5) extending substantially parallel to the yarn sheets of the reinforcing layer, the thermoplastic matrix thread (3 ) extends between the reinforcing layer and the second thermoplastic thread (5).

Textile semifinished product according to claim 1, characterized in that it comprises at least two reinforcing layers which extend in mutually substantially parallel planes.

Semifinished textile product according to claim 4, characterized in that the at least one thermoplastic matrix thread (3) between two levels of reinforcing layers.

Textile semi-finished product according to claim 5, characterized in that the at least one thermoplastic matrix thread (3) is designed as a partial weft.

Textile semi-finished product according to one of claims 4 to 6, since ^¬ characterized by that the individual threads or thread saddle ^¬ ren (2, 4, 6) of at least two of the reinforcement layers to one another enclose an angle, preferably orthogonal to each other substantially.

Semifinished textile product according to claim 7, characterized in that at least one thermoplastic matrix thread (3) extends through intersection regions of individual threads or suture bundles (2, 4, 6) of the at least two reinforcement layers.

Textile semi-finished product according to one of claims 4 to 6, since ^¬ characterized by that run parallel to each other, the individual threads or thread saddle ^¬ ren (2, 6) of at least two of the reinforcement layers substantially.

Textile semifinished product according to claim 9, characterized in that for fixing the reinforcing layers against each other a second thermoplastic matrix thread (7) is formed as a partial weft on the outside of the reinforcing ^¬ layer to be fixed.

Textile semi-finished product according to one of claims 1 to 10, as ^¬ characterized by that at least one connecting thread (1) is formed thermoplastically.

12. Textile semi-finished product according to claim 11, characterized in that the melting temperatures of thermoplastic matrix thread (3, 7) and thermoplastic connecting thread (1) differ from each other.

13. A textile material according to any of claims 1 to 12, as ^¬ characterized by that the thermoplastic Matrixfa ^¬ (3) between the stitches of the connecting thread part ^¬ example rectilinear and / or arched runs.

14. Semi-finished textile product according to any one of claims 1 to 13, ^¬ characterized in that the individual threads or Fadenscha ^¬ ren (2, 4, 6) fibers selected from the group consisting of glass fibers, carbon fibers, basalt fibers, high-strength polymer fibers and mixtures it.

15. fiber composite workpiece, obtainable by heating and forming a textile semifinished product according to one of claims 1 to 14.