EP2588658B1 - Sewing thread and method for producing a sewing thread - Google Patents

Description

FIELD OF THE INVENTION

The present invention relates to a sewing thread and a method for producing a sewing thread. In particular, the present invention relates to a sewing yarn in the form of a staple fiber yarn made of carbon and in particular to a corresponding production method. The present invention further relates to measures for improving the properties of CF rovings and CF staple fiber yarns, in particular for use in embedding in elastomers, thermoplastics and / or thermosets, e.g. Phenolic resins.

BACKGROUND OF THE INVENTION

In the manufacture, processing and use of yarns and particularly sewing threads, ie yarns used and used in sewing processes, restrictions and other circumstances that can not be tolerated are often encountered due to the underlying starting materials and their properties.

This concerns aspects of the static and / or dynamic loadability and the internal and external friction as well as related consequences, eg due to internal and external friction resulting influences of the yarn or sewing thread regarding structure and properties, but also aspects of friction related contamination of the yarn or the environment of use by abrasion and the like. EP-A-2 147 776 shows a sewing yarn (ie, attachment yarn) formed as a spun yarn from a staple fiber material of staple fibers formed with or from carbon fiber materials and coated or impregnated with one or more coating materials and / or impregnating materials. EP-A-2,160,072 shows a similar sewing thread. US-A-2007/0148455 describes a yarn which can also be used for sewing, which is formed as spun yarn from a staple fiber material, which is formed with or from carbonized PAN fibers.

SUMMARY OF THE INVENTION

The invention is based on the object of specifying a sewing thread and corresponding production method, in which a constant and constant profile of the sewing thread can be ensured in a simple and nevertheless reliable manner and in particular with simple processability.

The object underlying the invention is achieved according to the invention with the features of independent claim 1, and in a method for producing a sewing thread according to the invention with the features of independent claim 5 in a sewing thread. Advantageous developments are defined in the dependent claims.

According to a first aspect of the present invention, a sewing thread is provided, which is formed as a spun yarn from a staple fiber material with or from staple fibers - and which is formed with or from one or more carbon fiber materials.

It is thus a first aspect of the present invention to form a sewing yarn with a particularly constant property profile in that it is or will be formed on the basis of or in the manner of a staple fiber yarn, with this staple fiber yarn and ultimately the sewing yarn itself with or from one or more Carbon fiber materials is or is formed.

Carbon fibers have proven to be particularly advantageous in chemical and physical process engineering and in many technical applications proved, because they can be adjusted in their property profile in a particularly suitable and constant manner and as such in terms of their mechanical, thermal, chemical and electrical properties of particular advantage in many applications.

The staple fibers as individual fibers are wholly or partly coated or impregnated in their entirety with one or more coating materials and / or impregnating materials.

The staple fiber yarn may be wholly or partly obtained from a multifilament yarn or roving, in particular from a Multifilamentcarbonroving or be.

The staple fiber yarn may in particular be wholly or partly obtained from a stretch-broken and / or cut multifilament yarn or roving, in particular from a stretch-broken multifilament carbon roving.

Furthermore, the staple fiber yarn may also be wholly or partially obtained from a textile fabric, a scrim, in particular a carbon fabric, a woven fabric, in particular a carbon fabric, and / or combinations thereof.

In particular, the use of recycled materials is conceivable.

In addition, the staple fiber yarn may be formed with or from filaments or filament sections having a length in the range of about 10 mm to about 250 mm.

Thus, there are various possibilities on the basis of which the underlying staple fiber yarn for a sewing yarn can be developed.

All aspects are of course also applicable to multifilament yarns or multifilament rovings and their transformation, e.g. their introduction into a surrounding matrix material, e.g. of an elastomer, thermoplastic and / or thermoset, e.g. a phenolic resin, wherein in particular an impregnation and / or coating, e.g. by precipitation or in the manner of a coating, aspects of the static and / or dynamic loading, the internal and / or external friction and / or the embedding in and interaction with the embedding matrix material and thus the transmission of force, thrust and pressure are advantageous to develop.

The staple fiber yarn may be formed with or from filaments or filament portions based on glass material fibers, acrylic material fibers, polyester fibers, polyamide fibers, basalt material fiber and / or combinations thereof, as one or a hybrid type, preferably having a carbon fiber content in the range greater than 10 %.

The coating and / or the impregnation with the coating material or the impregnating material can be or are formed by etching and in particular as a coating.

The basic principles provided according to the invention are also applicable to fiber types other than carbon fibers and staple fibers, in particular with regard to coating and / or impregnation.

According to further aspects of the present invention, the principles on which the invention is based are also advantageously incorporated in corresponding production methods.

On the one hand, the present invention thus also provides a method for producing a sewing thread, in which the sewing thread is formed as a spun yarn from a staple fiber material with or from staple fibers and wherein the sewing thread is formed with or from one or more carbon fiber materials.

The staple fibers are wholly or partially coated or impregnated as single fibers in their entirety with one or more coating materials and / or impregnating materials.

The staple fiber yarn can be obtained procedurally wholly or partly from a multifilament yarn or roving, in particular a Multifilamentcarbonroving.

In this case, the staple fiber yarn can be wholly or partly obtained from a stretch-torn and / or cut multifilament yarn or roving, in particular a stretch-torn and / or cut multifilament carbon roving, wherein the process of stretch ripping and / or cutting can be designed to be integrated in particular in the process.

On the other hand, the staple fiber yarn can be wholly or partly obtained from a textile fabric, a scrim, in particular a carbon web, a fabric, in particular a carbon fabric, and / or combinations thereof, e.g. also as part of a recycling process.

The filaments or filament sections for the staple fiber yarn may be formed to have a length in the range of about 10 mm to about 250 mm.

The staple fiber yarn may be formed with or from filaments or filament portions based on glass material fibers, acrylic material fibers, polyester fibers, polyamide fibers, and / or combinations thereof, as one or a hybrid type, preferably having a carbon fiber content in the range of more, besides carbon-based materials than 10%.

According to the method, the coating and / or impregnation with the coating material or the impregnating material can be formed by quenching and in particular as a coating.

These and other aspects will be explained by way of example on the basis of the accompanying schematic drawings.

BRIEF DESCRIPTION OF THE FIGURES

Fig. 1A - D

show in schematic and sectional cross-sectional view different embodiments of the sewing thread.

Fig. 2

is a schematic block diagram showing an embodiment of a method according to the invention for producing a sewing thread according to the invention.

Fig. 3, 4

FIG. 12 are schematic block diagrams illustrating detail aspects of embodiments of the method of producing a sewing thread according to the present invention. FIG.

DETAILED DESCRIPTION OF THE EMBODIMENTS

Hereinafter, embodiments of the present invention will be described. All embodiments of the invention and also their technical features and properties can be isolated individually or combined randomly combined with each other arbitrarily and without restriction.

Structurally and / or functionally identical, similar or identically acting features or elements are referred to below in connection with the figures with the same reference numerals. Not always will a detailed description of these features or elements be repeated.

First of all, reference is made to the drawings in general.

The present invention relates to staple fiber yarns of carbon and their manufacture, and to methods and possibilities for improving the properties of CF rovings and CF staple yarns, in particular also for use in elastomers, thermoplastics and thermosetting plastics, eg in phenolic resins.

This leads to tensile forces in the process, which can have a negative effect on the finished product. The stresses can damage the filaments 20 and thus reduce the mechanical strengths. Process disturbances may also develop, e.g. in connection with a yarn break or the like.

With the help of a rotation in the yarn 10, the surface can be increased, this rotation is used to protect the yarn composite. However, here too, the processing is limited. The filament yarns have a very high strength, but a low elongation. On the other hand, if you make a staple fiber yarn, i. Spun yarn 10 of staple fibers 20 of limited length, so can produce a yarn 10 with higher elongation.

As a raw material for the stretch-broken staple fiber yarn, a carbon roving with a high filament number can be used. The production of a 1K roving with a filament diameter of or below 6 microns, however, is very expensive.

Carbon fibers have a high strength, but unfortunately also a low ductility. For this reason, carbon fibers in textile processes can only be processed comparatively slowly and at relatively high cost.

It is also an object of the invention to provide a coating for carbon fibers 20, yarns 10 of stretched fibers 20 or Panox 20, as well as other brittle fibers which improve the processing properties.

Among other things, the improvement can be measured by fiber abrasion, the number of strand breaks and the processing speed become. In this case, an improvement is then achieved in consequence also in the sewing and knitting processes. Such sized yarns can be woven more effectively, resulting, among other things, in higher productivity.

• 1. Streckreißen und/oder Schneiden eines Multifilamentrovings, z.B. eine Rovings von über 48K, oder von textilen Flächengebilden, z.B. Recyclingmaterial aus Carbongelege oder -gewebe zu Filamenten, die eine Länge im Bereich von 10 - 250 mm haben.
• 2 Auflösen, Parallelisieren in einer Karde.
• 3. Herstellung eines Bandes in einer Strecke.
• 4. Gegebenenfalls und in Abhängigkeit von einem einzusetzenden Spinnverfahren, Weiterverarbeitung zu einer Flyerlunte.
• 5. Garnherstellung durch Spinnen, z.B. mit Hilfe einer Ringspinnmaschine, Rotorspinnmaschine oder einer Friktionspinnmaschine.
• 6. Zwirnherstellung, z.B. zu einem Zweifachzwirn.
• 7. Optionale Avivierung mit Textilhilfsmittel zur Verbesserung des Haft-/Gleitverhaltens, der Herabsetzung der statischen Reibung, der Erhöhung der dynamischen Reibung, dem thermischen Schutz sowie der Verbesserung des Faserreibverhaltens und Erhöhung der Dehnung.

An embodiment of a possible production method according to the invention may comprise the following steps:

• 1. stretch breaking and / or cutting a multifilament roving, eg a roving of more than 48K, or of textile fabrics, eg recycled material of carbon fabric or fabric into filaments having a length in the range of 10 - 250 mm.
• 2 dissolve, parallelize in a card.
• 3. Making a band in a track.
• 4. If necessary, and depending on a spinning process to be used, further processing to a Flyerlunte.
• 5. yarn production by spinning, for example by means of a ring spinning machine, rotor spinning machine or a friction spinning machine.
• 6. Twisting, eg to a twofold twist.
• 7. Optional finishing with textile auxiliaries to improve the adhesion / sliding behavior, the reduction of static friction, the increase of dynamic friction, the thermal protection and the improvement of the fiber friction behavior and increasing the elongation.

An embodiment of the surface treatment can be based on the following aspects according to the invention:
The use of an elastic sizing with a low glass transition temperature to coat fibers 20 and yarns 10 results in a more suitable surface which ensures improved processability.

Self-crosslinking carboxylated styrene-butadiene copolymers, which crosslink in a thermal drying process, have proven particularly suitable.

In addition to a very smooth surface, in particular the electrical contactability of the fibers is an interesting property. Here, the use as a heat conductor in conveyors, as or in hoses, conveyor belts, heatable fabrics, etc. conceivable.

Due to the flexibility, a gentle shear transfer between the fibers 20 and thus a good force in the entire strand 10 or the entire yarn 10 is ensured.

This procedure is also suitable for the treatment of all fiber types, but especially of carbon and ceramic fibers.

Furthermore, this also ensures good compatibility with elastomer matrices.

With regard to the improvement of properties of CF rovings and CF staple fiber yarns, in particular for use in elastomers or thermoplastics, in particular the improvement of the process properties by abrasion reduction and / or abrasion prevention is realized, in particular in structures, the emergence by braiding, sewing, Weaving or the like.

The avoidance of friction between individual filaments, which is also referred to as internal friction, is made possible by a partial or complete Coating, impregnation and / or wrapping of a respective single filament or portion of a single filament with a thermoplastic or other equivalent material which reduces friction. As a result, improved stability is achieved, especially under dynamic load. In the application, this may concern elevator cables, drive belts, conveyor belts or the like.

Further, by impregnation, coating and / or wrapping, improved incorporation of a CF roving, CF staple fiber yarn or respective monofilaments in matrix systems, e.g. made of rubber, thermoplastic and / or duroplast, possible. Furthermore, an improvement of the transmission of force, thrust and / or pressure can be achieved by such impregnation, embedding and / or coating.

According to the invention, corresponding methods of introducing thermoplastic fibers 20 and / or materials into continuous rovings or filament yarns are described for this purpose. Since such processes can also take place with the supply of heat, it is achieved in such embodiments that the thermoplastic melts and completely incorporates the CF filaments. The complete incorporation and protection of the filaments 20 or filament sections 20 reduces the internal friction among each other and thus increases the dynamic strength of the product.

An impregnation 40 and / or coating 30 of the fibers 20, fiber groups 25 or the yarn 10 as a whole reduce or prevent on the one hand the formation of dust by abrasion, but on the other hand also the adhesion resulting or existing dust on the fibers 20, the fiber groups 25 or the yarn 10th as a whole.

Now, reference will be made in detail to the drawings.

The Fig. 1A to 1D describe in schematic cross-sectional view various embodiments of a sewing thread 10.

In the embodiment of the Fig. 1A (Not according to the invention) is a schematic cross-sectional view of a group 25 or a bundle 25 of individual filaments 20 or fibers 20 of a fiber material 20 'shown, which form a group 10 or bundle 25 after a corresponding spinning process, a yarn 10 and in particular a sewing thread 10.

It is essential to the invention that the actual fibers 20 are staple fibers, ie fiber or filament sections of finite length, which are or are spun together by a spinning process. The material 20 'of the underlying fibers 20 or filaments 20 is a carbon material or carbon material so that the filaments 20 or fibers 20 may be referred to as carbon fibers or carbon fibers in a narrower or broader sense.

In the embodiment of the Fig. 1B the individual fibers or filaments 20 are formed on their surface 20a, that is to say the lateral surface 20a of the fibers 20 or filaments 20, with a coating 30 of a coating material 30 '.

In the embodiment of the Fig. 1C the individual fibers 20 or filaments 20 are formed over their surface 20a, that is to say over their lateral surface 20a with an impregnation 40 with an impregnating material 40 '. That is, the impregnating material 40 'penetrates or penetrates the surface 20a of the fibers 20 or filaments 20 to effect surface modification there.

The representations of the Fig. 1B with the coating 30 and the Fig. 1C with impregnation 40 represent extreme perspectives of the conditions expected in reality. As a rule, mixing processes will take place as soon as possible a coating material 30 'or an impregnating material 40' is applied to the surface 20a of any fiber 20 or any filament 20. This means that the applied materials 30 ', 40' on the one hand realize or effect a coating 30, but on the other hand also an impregnation 40.

In the embodiment of the Fig. 1D (Not according to the invention) the group 25 or bundle 25 of the plurality of fibers 20 or fiber segments 20 is embedded in an embedding 50 with or of an embedding material 50 'such that the fibers 20 or fiber sections 20 no longer individually or individually with their surface 20a in Appear appearance.

Of course, in connection with the embodiments of the Fig. 1B and 1C Aspects 50 are also combined with the embedding 50, for example, by embedding fibers 20 or fiber sections 20 formed as a group 25 with a coating 30 or an impregnation 40 overall in an embedding 50.

The Fig. 2 shows in the manner of a schematic flow diagram aspects of an embodiment of the method according to the invention for producing a sewing thread 10 according to the invention.

After a preparatory step S0, staple fibers or a staple fiber material are provided in a subsequent step S1.

In an intermediate processing step S2, the provided staple fiber material is optionally processed between, for example, to dissolve or produce a certain order of the staple fibers or to perform a surface treatment or the like. However, this step of intermediate processing S2 is optional and only provided in certain embodiments of the manufacturing method according to the invention, that is not mandatory in each embodiment of the invention.

This is followed by the step of actually producing the sewing thread 10, namely a spinning process S3 of the staple fibers provided and, if applicable, between processed or between treated staple fibers.

It may then be followed by a post-processing step in which the resulting product is considered a roving, e.g. is still surface-treated and / or introduced into an embedding 50.

The final step S5 ends the process.

The Fig. 3 shows partial aspects of step S1 of providing the staple fibers or the staple fiber material.

In this case, in the embodiment presented here, first a roving, e.g. in the sense of a multifilament roving on the basis of a carbon fiber material or carbon fiber material, but optionally also based on other fiber materials, provided in a first substep T1.

This is followed by a process T2 of so-called stretch-tearing and / or cutting, in which the individual filaments of the roving, which are continuous per se, are subdivided into fiber or filament segments or sections in a more or less defined manner. This subdivided material then forms the starting material for the further processing processes.

Alternatively, e.g. provided already presented fiber section material, which is e.g. from a recycling process and fibrous waste, e.g. used in a felt-like way.

Fig. 4 shows partial aspects of the optional intermediate processing step S2.

In this embodiment, in a first substep U1, the basic staple fiber material provided is dissolved and / or parallelized, by means of a so-called carding machine.

This is followed by a second sub-step U2 of the production of a strip in a route.

This is then followed by the third sub-step U3, the intermediate processing to a so-called Lunte or Flyerlunte.

As already described above, the actual production of the sewing thread 10 takes place in the context of a spinning process of the underlying staple fiber material, e.g. using a ring spinning machine, a rotor spinning machine or a friction spinning machine.

In order to improve the properties, and in particular to increase the stability of the sewing thread 10, the basic yarn obtained can be regarded as a roving and subjected to a twisting process, in order, for example, to apply a twisting process. to produce a double thread or the like.

Before and optionally thereafter, a refinement process takes place in the sense of coating, trimming, impregnation and / or embedding.

The following tables show properties of embodiments of sewing threads 10 made according to the invention. <u> Embodiment 1: </ u> Physical size Unit of measurement Numerical mean Tensile strength (impregnated) MPa 2750 Tensile strength (dry) MPa 1000 yarn strength N 43 Young module (train) GPa 220 Stretch impregnated) % 1.1 density g / cm ³ 1.79 Knot tensile strength N 2.2 Loop tensile strength N 14.4 Electrical resistance Ω / m averaged 405 and 430 respectively Specific electrical resistance Ω / micron 16.7 Staple fiber length mm Average: 123 Max: 220 Min: 15 twist tpm 310 S / 230T Physical size Unit of measurement Numerical mean Tensile strength (impregnated) MPa 2950 Tensile strength (dry) MPa 820 yarn strength N 90 Young module (train) GPa 200 Stretch impregnated) % 1.4 density g / cm ³ 1.79 Knot tensile strength N 2.7 Loop tensile strength N 60 Electrical resistance Ω / m averaged 140 Specific electrical resistance Ω / micron 16.0 Staple fiber length mm averaged: 123 maximum: 220 minimal: 15 twist tpm 310 S / 230T

In a further development of the method according to the invention, a textile structure is formed with or out of the sewing thread 10, in particular by means of a weaving process, preferably as one or two-dimensional textile type, one or in the manner of a woven, laid, braided, knitted, knitted fabric and / or or their combinations.

LIST OF REFERENCE NUMBERS

10

Yarn, sewing thread

20

fiber

20 '

fiber material

25

Group of fibers, fiber group

30

coating

30 '

coating material

40

impregnation

40 '

waterproofing

50

embedding

50 '

embedding material

Claims (7)

1. Sewing thread (10) that is formed as a spun yarn made of a staple fibre material consisting of staple fibres (20),
   and contains or consists of carbon fibre materials (20'),
   wherein all of the staple fibres (20) are coated or impregnated as individual fibres (20), fully or in part, with one or more coating materials (30') and/or impregnation materials (40').
2. Sewing thread (10) according to claim 1,
   containing the coating material or materials (30') and/or impregnation material or materials (40') in an amount in the range of from 0.1% to 50%.
3. Sewing thread (10) according to either of the preceding claims,
   wherein the staple fibres have a length in the range of from 10 mm to 250 mm.
4. Sewing thread (10) according to any of the preceding claims, comprising staple fibres that are based on glass fibres, acrylic fibres, polyester fibres, polyamide fibres and/or combinations thereof, and in the form of a hybrid having a carbon fibre proportion in the range of more than 10%.
5. Method for producing a sewing thread (10) according to any of the preceding claims that is formed as a spun yarn made of a staple fibre material consisting of staple fibres (20), comprising the following steps:

   a) providing a staple fibre material containing or consisting of carbon fibre materials (20');

   b) coating and/or impregnating all of the staple fibres (20) as individual fibres (20), fully or in part;

   c) spinning the staple fibre material.
6. Method according to claim 5, wherein the staple fibre yarn is formed by individual fibres (20) having a length in the range of from 10 mm to 250 mm.
7. Use of the sewing thread (10) according to any of claims 1 to 4 for producing a woven fabric, a laid fabric, a braid, a warp-knit fabric, a weft-knit fabric and/or combinations thereof.

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