DE102018001440A1 - threadlike structure - Google Patents

Abstract

The present invention relates to a thread structure with mutually parallel direction laid fiber bundles, composed of individual filaments and crossing each other to form distances between the filament bundles, each of which is provided in the manner of a composite material volume-filling with a thermoplastic matrix.

Description

The present invention relates to a thread structure according to claim 1.

Prepregs are well known.

They are semi-finished products, consisting of a thread structure that is covered with a plastic. From these semi-finished products end products are produced by a pressing process with appropriate heating, which can also be deformed three-dimensionally. Here, one makes use of the composite structure of prepregs, because the originally present in the prepreg thread layers in the final product cause a stabilization, because even the final product, in almost any form, then consists of a composite material.

The object of the present invention is to produce such prepregs with an increased utility value in a simple manner, while ensuring that the composite structure uniformly stabilizes the final product over the entire areal configuration of the final product.

This object is achieved by the features of the main claim.

From the invention there is the advantage that such a thread structure can be produced in the simplest manner, practically as a raw fabric, in open form, which already has a dimensionally stable structure a priori, because the thermoplastic matrix in the individual filament bundles stabilizes not only the filament bundles, but also the entire thread structure.

It depends essentially on the fact that the thermoplastic matrix is present in a volume which can flow into the intermediate spaces provided between the individual bundles of fibers in a subsequent pressing operation under the known parameters of pressure, temperature and time and in this way in this downstream pressing process for a uniform Laying of the individual threads in the final product ensures.

It is therefore essential idea of the invention, between the individual laid fiber bundles, each of which runs parallel to the direction and form spacings between them in the transverse direction, the distances to be determined so large in view of the present in the respective bundle of fibers thermoplastic matrix that this thermoplastic matrix together with the under Pressure from each bundle of filaments flowing outward forms a uniformly interspersed uniformly with individual filaments in each direction composite body, which is also interspersed by the manufacturer provided surplus of thermoplastic matrix over the entire longitudinal and transverse dimensions with the thermoplastic matrix.

This is a significant advantage of the invention, because the invention has recognized that the flow process of the individual threads in the originally available free areas between the filament bundles in each direction causes virtually homogeneous material properties, so that corresponding material properties such as tensile strength, etc. can be ensured.

It is particularly advantageous that the dimensioning of the filament bundles, so the cross-sectional dimensions and the associated released locations between the filament bundles can be easily adapted to the respective end product.

Of course, the open lattice structure applies in all directions, which are transverse to the respective laying directions of the directionally parallel bundles of fibers.

The thread structure of the present invention can be made as a semi-finished, sandwich or lightweight board.

It is essential in any case, the enforcement of the thermoplastic matrix through the entire bundle of filaments. This means that practically no air pockets in the thermoplastic matrix should be allowed, at least in the technically feasible range, so that the flow of the matrix in the downstream process can also lead to a full-volume matrix content in the final product.

In the downstream process, a complementary thermoplastic material may also be readily machined so that, thanks to the invention, anchoring this supplemental thermoplastic material on both sides as a result of penetration through the plastic matrix present in the original prepreg results in improved material characteristics.

Of course, it is recommended to use plastics that are compatible with the original plastic of the prepregs.

In that regard, the invention offers the additional advantage that in the second processing step, a lower pressure is sufficient to bring the thermoplastic materials together in Kapilarverbund.

This is achieved in particular by the fact that the elements already present in the original bundles of filaments are impregnated with a thermoplastic matrix and, therefore, that in the End product existing thread structure only has to be contacted only in the microscopic range of the supplementary used thermoplastics under a pressure that merely produces the Kapilarverbund.

Attention is also paid to the injection technique for the injection of thermoplastic material into the originally existing bundles of fibers.

The thermoplastics used today have well-known kinematic state variables that can be adjusted so that it can come to a full volume impregnation of each individual bundle of fibers, so that later end products no longer have air pockets.

Thus, the invention shows that it can, hitherto unknown, also have constant grating values in the structure of the end product, so that reliable predictions with regard to the material characteristics can be made.

Since the invention basically has holes defined by longitudinal and transverse dimensions in all embodiments, which are located between the individual bundles of filaments, at least before the filament bundles are pressed under the influencing variables of temperature, pressure and time in a further processing step, such a filament structure can also be conveyed over its Grid values are defined.

Grid values are those characteristics which define the size of the recesses between the filament bundles, for example the X or Y values in a Cartesian coordinate system.

In the case of multidirectionally laid thread bundles, this applies accordingly.

In addition to the anchoring in the capillary composite, it is also of particular advantage that there may be a possibility for chemical anchoring of the subsequently used thermoplastics and the already mentioned possibility of changing the geometry of the thread with regard to the structure of the final product.

From the dependent claims, advantageous developments of the invention.

It can be provided only two preferably perpendicular intersecting directions for the filament bundles.

Depending on the requirements of the end product, it may also be advantageous to provide more than two directions. For this embodiments are given.

In any case, it is essential that at least as many layers of individual threads are provided in each bundle of filaments, and so much thermoplastic matrix that the existing in the original thread structure side gaps between the bundles of filaments are filled by flowing the monofilaments in the adjacent originally left lateral distances.

The production of the thread structure as a roller conveyor offers manufacturing technology the lowest cost per unit length and in particular the ability to prepare the roller conveyor in the form of blanks for further processing.

In the following the invention will be explained in more detail by means of exemplary embodiments.

• 1 das Grundprinzip der Erfindung;
• 2 eine dreidimensionale Ansicht der Erfindung, hier in Form eines Gewebes;
• 3 eine vergrößerte Ansicht eines Fadenbündels;
• 4 eine in mehr als zwei parallelen Richtungen verlegte Anordnung von Fadenbündeln;
• 5 schematische Darstellung des Fließvorgangs;
• 6 Aufmachung der Fadenstruktur, Zuschnitt, Endprodukt.

Show it:

• 1 the basic principle of the invention;
• 2 a three-dimensional view of the invention, here in the form of a fabric;
• 3 an enlarged view of a thread bundle;
• 4 an array of filament bundles laid in more than two parallel directions;
• 5 schematic representation of the flow process;
• 6 Presentation of the thread structure, cut, final product.

Unless otherwise stated below, the following description applies to all figures.

The figures show a thread structure 1 with yarn bundles laid parallel to each other in directional direction 2 . 3 . 4 ; 2 ' . 3 ' . 4 '; 2 '' . 3 '' . 4 '' ,

It is essential that between the parallel filament bundles in a direction transverse thereto distances exist, in which there is no material, and this transverse to all laying directions in which the respective filament bundles are laid.

It is an open fabric, but it is quite possible a scrim or another form of the respective flat end product of the thread structure without limiting the invention thereto.

In that regard, the invention also applies to, for example, unidirectional thread bundles, in which only laid transversely to the direction of the Thread bundles significant distances in the sense of the invention exist.

Unidirectional thread bundles could be fixed in this case by occasional transverse auxiliary threads to each other.

This product of the thread structure can be used to produce a wide variety of processed components for all sorts of industrial applications using a downstream process, such as injection molding or forming.

It is essential to the extent that the thread structure is completely and uniformly impregnated with a thermoplastic matrix form fit and that the filament bundles can not move relative to each other after the filament structure has been preconsolidated accordingly. Preconsolidation in this sense means that a dimensional stability of the lattice structure with the openings therein must be achieved.

This is known per se by known manufacturing methods such as production of a fabric, a fabric or the like.

In particular 3 shows are the thread bundles 2 . 3 . 4 ; 2 ' . 3 ' . 4 '; 2 '' . 3 '' . 4 '' from the thermoplastic matrix 6 completely interspersed.

Each thread bundle consists of a large number of individual threads shown 5 which are embedded in the full-volume thermoplastic matrix.

In this case, the thermoplastic matrix present in each bundle of threads connects the pairs of intersecting bundles of fibers to each other in a dimensionally stable manner at the connection points of the fabric / cover, so that semifinished products made of the thread structure can be cut to any desired size to fit the respective end product.

This offers the advantage that it is easily possible for the end user to position the semifinished product as a cutting precisely in the end product without the basic structure of the fabric / fabric changing during further processing.

To achieve a homogeneous installation pattern of the respective bundles of fibers in the end product, it is proposed that the bundles of fibers have the same width and the same thickness in each direction.

For one exemplary embodiment, it is proposed that the fabric or scrim constructions have a thread spacing of more than 2 mm and, depending on the requirement profile for the end product, be arranged at right angles and / or biaxially and / or multiaxially in different directions.

However, this is not a limitation of the invention. In this respect, all technically reasonable grid structures with corresponding longitudinal and transverse dimensions of the distances between the filament bundles are covered by the claim.

In particular 3 also shows, each bundle of threads knows multilayered individual threads 5 on, which spread more or less evenly in the bundle of fibers and are enclosed by the thermoplastic matrix flush and full volume.

For this reason, the filament bundles have a width 9 and a height 10 , so that so many layers of individual threads can be used in each bundle of threads and so much thermoplastic matrix can surround these individual threads, that when pressing the thread structure under the known parameters pressure, temperature and time, the originally existing distances 7.8 between the individual filament bundles by flowing the monofilaments 5 into the neighboring originally released distances 7.8 be filled.

It is essential in this process that in the process of post-processing for the production of the final product 14 As much pressure, temperature and time is exerted on the originally existing structure, that the existing thermoplastic matrix at least in the originally released distances 7.8 taking along the individual threads embedded in it 5 can be displaced, so that in the end a three-dimensionally shaped end product arises with evenly embedded individual threads originating from the original bundles of fibers.

In addition to this shows the 6 the presentation of the thread structure according to the invention as a roller conveyor 12 For example, for the production of blanks 13 can serve, which can be processed as a final product after appropriate 3-D deformation, here for example as a can lid 14 ,

Furthermore, it should be expressly mentioned that the thread structure can also be produced in the form of a presentation in carbon look, in order to be able to serve appropriate customer groups.

The invention has further made possible the surprising finding that not only thermoplastic materials alone can be used, but also thermosetting plastics.

This was especially in thermosetting plastics of only small thickness, as this - assuming a correspondingly small thickness - remain elastic during curing.

Furthermore, the invention also relates to a method for producing the thread structure according to the invention, which has been found to be advantageous.

In this method, which applies to all the embodiments already mentioned, initially an intermediate structure of a flat structure, such as a fabric or a scrim is produced, wherein the filament bundles of the subsequently desired thread structure to be laid accordingly.

This intermediate structure is then so abundantly charged with a liquefied plastic, which may be both thermoplastic and thermosetting, that after applying the excess plastic must be removed.

However, this excess plastic is only removed to the extent that each bundle of fibers remains full of volume of remaining plastic filling.

In this way, it is ensured that each individual bundle of fibers forms a composite material for itself with a plastic matrix which is virtually free of air inclusions and in this way gives the thread structure in each main direction of the laid bundles of fibers considerable strength properties.

Even while the originally liquefied plastics are liquid, the undesired excess quantities are removed mechanically or aerodynamically from the intermediate structure by suitable measures.

This can be done for example via roller pairs or cross-flow.

Thereafter, at least once the mandatory holes between the individual filament bundles are free.

If the originally liquefied plastic has not yet dried, it is recommended to subject the lattice structure prepared in this way to a subsequent drying, this can be done without contact, for example by infrared heating or the like in an oven or under an infrared radiator, so that subsequently the dried finished product, the thread structure according to the invention, can be rolled up so as to become role presentation.

Surprisingly, it has been shown that even a thermoset plastic interspersed thread structure can be rolled up.

The small thickness of the thermosetting plastic on the thread structure allows a high flexibility, without risk of breakage, although it is a thermosetting plastic.

LIST OF REFERENCE NUMBERS

1

threadlike structure

2

Thread bundles, horizontal

3

thread bundle

4

thread bundle

2 '

Thread bundles, vertical

3 '

Thread bundles, vertical

4 '

Thread bundles, vertical

2 ''

Thread bundles, diagonal

3 ''

Thread bundles, diagonal

4 ''

Thread bundles, diagonal

5

monofilament

6

Thermoplastic matrix

7

distance between 2 . 3 . 4

8th

distance between 2 ' . 3 ' . 4 '

9

width

10

thickness

11

flow process

12

roller conveyor

13

cut

14

can end

Claims (16)

Thread structure (1) with mutually parallel direction laid yarn bundles (2, 3, 4); (2 ', 3', 4 '); (2 '', 3 '', 4 '') which are composed of monofilaments (5) and intersecting each other to form transverse to their respective installation direction formed distances to the respective adjacent bundle of filaments, wherein only the filament bundles (2, 3.4); (2 ', 3', 4 '); (2 '', 3 '', 4 '') are provided with the release of the distances (7,8) therebetween in the manner of a composite material with a thermoplastic matrix (6). Thread structure (1) after Claim 1 , characterized in that the thread bundles (2,3,4); (2 ', 3', 4 '); (2 '', 3 '', 4 '') are fully penetrated by the thermoplastic matrix (6). Thread structure (1) after Claim 1 or 2 , characterized in that the thermoplastic matrix (6) in the filament bundles (2,3,4); (2 ', 3', 4 '); (2 '', 3 '', 4 '') is injected. Thread structure (1) according to one of Claims 1 to 3 , characterized in that the filament bundles (2,3,4) and (2 ', 3', 4 ') are provided in only two intersecting directions. Thread structure (1) according to one of Claims 1 to 3 , characterized in that the thread bundles (2,3,4); (2 ', 3', 4 '); (2 '', 3 '', 4 '') are provided in more than two intersecting directions. Thread structure (1) according to one of Claims 1 to 5 , characterized in that the thread bundles (2,3,4); (2 ', 3', 4 '); (2 ", 3", 4 ") have the same width (9) and the same thickness (10) in each direction. Thread structure (1) after Claim 6 , characterized in that each thread bundle (2,3,4); (2 ', 3', 4 '); (2 '', 3 '', 4 '') has multilayered filaments. Thread structure (1) after Claim 7 , characterized in that at each thread bundle (2,3,4); (2 ', 3', 4 '); (2 '', 3 '', 4 '') are provided as many layers of individual threads (5) and so much thermoplastic matrix (6) that when pressing the thread structure under the known parameters pressure, temperature and time, the original distances (7 , 8) between the individual filament bundles (2, 3, 4); (2 ', 3', 4 '); (2 '', 3 '', 4 '') are filled by flowing (11) of the monofilaments (5) in the adjacent originally released distances (7,8). Thread structure (1) according to one of Claims 1 to 8th , characterized in that the thread structure (1) is opened as a roller conveyor (12). Thread structure (1) after Claim 9 , characterized in that blanks (13) for the end product (14) are produced from the roller conveyor (12). Thread structure (1) according to one of Claims 1 to 10 , characterized in that the thread structure has carbon-look presentation. Method for producing a thread structure (1) according to one of Claims 1 to 11 , characterized in that after the production of a flat structure as an intermediate structure, which then corresponds to the thread structure, the intermediate structure is so abundantly charged with a liquefied plastic that after the application of excess plastic is only removed so far that each filament bundle (3.4 ) of remaining plastic volume filling fully permeated remains. Method according to Claim 12 , characterized in that the excess plastic is squeezed off by a parallel to the path of movement of the thread structure on both sides arranged to this pair of rollers and that before the subsequent drying a Querblasstrom is directed to the intermediate product to free the holes located between each thread bundles. Method according to Claim 12 to 13 , characterized in that after the squeezing by a preferably non-contact drying, the thermoplastic matrix is solidified. Method according to Claim 12 to 14 , characterized in that the drying takes place by means of an infrared source. Method according to Claim 12 to 15 , characterized in that after drying, the thread structure is fed to a reeling station, where it is wound up into a roll.

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