DE102019125531A1 - Method for producing carbon fiber strand sections, method for reinforcing components, carbon fiber strand section production device and component production device - Google Patents

Abstract

The invention includes a method for the production of carbon fiber strand sections, in which at least one carbon fiber band is provided in a continuous process with constant web material speed, the at least one carbon fiber band is drawn off in a fiber processing direction and expanded with heated spreader bars unstructured along its circumference to form at least one expanded carbon fiber band; solidifies the at least one spread carbon fiber band; the at least one spread and solidified carbon fiber band along the fiber processing direction is cut into several parallel carbon fiber strands and the carbon fiber strands are cut transversely to the fiber processing direction to form carbon fiber strand sections, as well as a method for reinforcing components in which carbon fiber strand sections produced according to the invention are introduced into a hardenable material. The invention further includes a carbon fiber strand section production device with at least one carbon fiber supply module, a spreading module, at least one consolidation module, a longitudinal cutting module, a transverse cutting module and at least one material conveying device that enables continuous material transport from the carbon fiber tape supply module to the transverse cutting module. In addition, the invention contains a component production device with a carbon fiber strand section production device according to the invention and a matrix material supply module connected to this via a conveying device.

Description

The present invention relates to a method for producing carbon fiber strand sections. The present invention also relates to a method for reinforcing components. The invention further relates to a carbon fiber strand section production device and a component production device.

Technical reinforcement fibers, here carbon fibers, are becoming increasingly important due to their excellent mechanical properties. In the form of short fibers (up to 25 mm in length) they are used in plastic and concrete components, particularly in the design of filigree and thin-walled structures. The reinforcement fibers can be used to increase mechanical strength and, in relation to concrete applications, to reduce crack propagation in the event of component failure. To make the best possible use of the material potential, the fibers must be separated into small fiber bundles, separated to a defined length and integrated into the composite material in a homogeneous distribution.

When using conventional steel reinforcement in concrete components, a minimum cover of 25 mm and more is often necessary so that appropriate corrosion protection can be guaranteed. By using technical fibers as reinforcement, the building can be built much more filigree, the drying time is much shorter and the distribution of the reinforcement in the concrete is much more homogeneous and does not have to be pre-fixed at the appropriate point. This enables a higher flexibility as well as a significant reduction of the preparation effort for the introduction and fixation with a simultaneous reduction of conventional steel reinforcement in the concrete processing and a greater design variety in the component design.

The fiber reinforcement can be made using continuous fibers, e.g. B. a fabric or scrim made of continuous fibers, and thus produced textile concrete, or using short fibers, which have a length of up to 25 mm, and fiber concrete made therefrom, can be introduced into the fresh concrete. The best mechanical properties are achieved with a combination of textile and fiber concrete.

The first concrete materials with short steel wires for reinforcement came onto the market as early as 1970. However, this was of subordinate importance, as there was as yet no design method like that for reinforced concrete. The later available measurements for fiber concrete opened up numerous areas of application. In the following years, numerous other reinforcement materials such as B. researched natural or glass fibers. However, for various reasons, such as insufficient strength and / or lack of alkali resistance, these were only able to gain acceptance on the market to a limited extent. In recent years, the use of carbon fibers has also been increasingly investigated. However, these are mainly found in the form of endless fiber-reinforced reinforcements, e.g. B. in the form of fabrics or scrims, application, since the excellent mechanical properties are particularly important here. The use of cut carbon fibers is currently not economical due to the high material price and low Tex numbers.

In the conventional production of chopped carbon fibers, continuous carbon fibers (e.g. 24k 1600g / 1000m or 50k ≙ 3300g / 1000m) are first produced and wound onto cores. The processing into cut fibers is only carried out in a downstream process.

Numerous manufacturers already offer such cut carbon fibers in a length of 6 mm. The cut fibers or cut fiber bundles have a good cohesion due to a sizing application during fiber production, but do not correspond to the properties and mechanical strengths required for use in the concrete or asphalt sector.

Carbon cut fibers for use in concrete components (≤ 200 tex) are currently not available on the market. For this reason, there is currently only the option of producing the cut carbon fibers from endless rovings (≤ 200 tex) by transverse cutting or cutting. Carbon fiber rovings of such fineness are characterized by a very high specific price, since carbon fiber production is very inefficient due to the energy-intensive process for this fiber fineness.

The composite properties of the fiber concrete are particularly dependent on the fiber distribution, the texture and the fiber content in the concrete. The goal is a homogeneous distribution and an omnidirectional, multidirectional orientation of the fibers. When it comes to fiber reinforcement, a distinction is made between water-dispersible and integral short fibers. Water-dispersible short fibers disperse completely in the concrete, the fiber bundles dissolve on contact with water and thus have a very large bonding surface with the concrete. Integral fibers, on the other hand, are present in a concrete matrix as filament bundles in which only the edge filaments are in contact with the concrete. This represents an application limit of integral fibers for concrete applications. In order to guarantee good mechanical properties, the short fibers of carbon fibers may therefore have a fiber fineness of Do not exceed 200 tex. This fiber fineness is exceeded with a filament count of 3000 or more filaments per roving.

With increasing fiber content in the concrete, the strength of the composite increases, while the flowability of the fresh concrete and the compressibility are reduced. Using water-dispersible short carbon fibers with a fiber volume content of up to 0.9%, scientific studies have already shown an increase in the tensile strength of the concrete by approx. 50%. In practice, however, short carbon fibers (≤ 25 mm) are not yet widely accepted due to the high material price for suitable fibers.

In the pamphlet EP 0 881 312 A2 describes a process for the targeted sizing of carbon fiber bundles each made of 20,000 to 150,000 filaments, so-called heavy tows, for the subsequent production of cut fibers. The process described relates to an epoxy-based, water-dispersible sizing system and the subsequent drying of the material. With various process parameters and material combinations, an optimum was determined for further processing into cut fibers. A disadvantage here is that the individual cut fibers are still very thick due to the very large fiber bundles with an average weight per unit length of 1.7 to 4 mg / mm and thus do not achieve adequate homogenization of the fibers in the concrete even when using a water-dispersible size can be.

In the pamphlet EP 1 788 146 B1 discloses a method for making water dispersible carbon fibers. These are formed by bundling a large number of individual fibers. This also produces bundles of 24,000 to 48,000 filaments. The size composition and content was determined to optimize the surface energy of the fibers. The fiber bundles are processed into short fibers with a length in a range from 3 mm to 30 mm for thermoplastic applications. Here, too, the starting fiber bundles are very heavy, which means that sufficient homogenization of the short fibers in the concrete cannot be achieved.

Various methods and devices for fiber spreading are, for example, from the publications DE 10 2005 052 660 B3 , WO 2011 1429 90 A1 , DE 10 2007 012 607 B4 and DE 10 2009 056 197 A1 known.

Due to the high material costs for fiber bundles with a filament count of a maximum of 3000 individual filaments, water-dispersible short carbon fibers have so far usually been produced from fiber bundles with at least 24,000 individual filaments, so-called heavy tows. When processing such cut heavy tows, however, due to the very large fiber bundles, even when using water-dispersible size, sufficient homogenization of the fibers in the concrete cannot be achieved.

From the pamphlet DE 10 2015 206 389 A1 a device for reducing the number of filaments of fiber rovings is known, in which the first fiber rovings are first spread by being pulled over a cylindrical body forming the spreading device, which has a plurality of circumferential grooves dividing in the circumferential direction of the body. As the fiber roving is pulled over the cylindrical body under tension in the circumferential direction, the fibers of the roving run into the fan-shaped dividing circumferential grooves of the cylindrical body, follow the circumferential grooves and are spread in this way.

Immediately after this very special spreading, they are divided into at least two second, parallel fiber rovings with a reduced number of filaments by means of at least one cutting means. This longitudinal cutting process is presumably only possible due to the previous expansion by means of the grooves, which gives the fibers a preferential alignment in the longitudinal direction. Otherwise at least some of the fibers would also be cut transversely in this process step, as a result of which the length of the second fiber rovings would be unstable and conveying problems would arise.

The known device also has a further cutting device for cutting the second fiber rovings largely transversely to their longitudinal direction. This creates sliver sections that can quickly disintegrate into individual fibers. The cutting device is a component of an automated device for producing a section of the second fiber roving and resin material-containing semi-finished product strip. In this case, the sliver sections produced fall directly onto a resin-hardener mixture previously applied to a carrier film, after which the sliver sections are incorporated into the matrix material by means of several rollers. In doing so, one must proceed very carefully, since otherwise the sliver sections will fall apart while they are being incorporated into the matrix material and the desired component strength will therefore not occur.

The invention is therefore based on the object of providing a method and a device for the production of carbon fiber elements, which with an advantageous Homogenization can be stably distributed in a hardenable material. Furthermore, a corresponding method for producing such carbon fiber elements and a corresponding device for reinforcing components with the aid of such carbon fiber elements are to be made available.

• - wenigstens ein Carbonfaserband bereitgestellt wird;
• - das wenigstens eine Carbonfaserband in einer Faserverarbeitungsrichtung abgezogen und mittels beheizten, entlang ihres Umfangs unstrukturierten Spreizstäben zu wenigstens einem gespreizten Carbonfaserband aufgespreizt wird;
• - das wenigstens eine gespreizte Carbonfaserband zu wenigstens einem gespreizten und verfestigten Carbonfaserband verfestigt wird;
• - das wenigstens eine gespreizte und verfestigte Carbonfaserband längs der Faserverarbeitungsrichtung in mehrere parallele Carbonfaserstränge längsdurchtrennt wird; und
• - die Carbonfaserstränge quer zu der Faserverarbeitungsrichtung zu Carbonfaserstrangabschnitten querdurchtrennt werden.

This object is achieved on the one hand by a method for the production of carbon fiber strand sections in which the following steps are carried out in the following sequence in a continuous process with constant web material speed

• - At least one carbon fiber tape is provided;
• - The at least one carbon fiber band is drawn off in a fiber processing direction and spread by means of heated spreading bars that are unstructured along their circumference to form at least one spread carbon fiber band;
• the at least one spread carbon fiber band is solidified to form at least one spread and solidified carbon fiber band;
• the at least one spread and solidified carbon fiber band is severed lengthways along the fiber processing direction into several parallel carbon fiber strands; and
• - The carbon fiber strands are severed transversely to the fiber processing direction to form carbon fiber strand sections.

The at least one carbon fiber tape used in the method according to the invention is provided in the form of a so-called roving. Rovings are bundles or strands of many individual continuous fibers, the so-called filaments, which are mostly parallel and stretched together. The rovings used according to the invention for the at least one carbon fiber ribbon can each be a carbon fiber roving made only of carbon fibers or a hybrid roving, preferably predominantly containing carbon fibers, which, for example, also has thermoplastic fibers in addition to carbon fibers as reinforcing fibers.

In the method according to the invention, at least one carbon fiber tape with a number of filaments of preferably at least 12,000, particularly preferably at least 24,000, is used.

The at least one carbon fiber band is advantageously provided in a rotation-free manner. This is ensured in particular by a tangential withdrawal of the at least one carbon fiber band from a reel.

In particular, the at least one carbon fiber band is provided with a constant tensile stress. Both the tangential withdrawal and the constant tensile stress are preferably achieved through the use of an electronically controlled gate.

When providing the at least one carbon fiber band, fiber rotations are to be avoided. Optionally, fiber guide elements can also be used for an optimal withdrawal of the at least one carbon fiber band.

In order to spread the at least one carbon fiber band to form a spread carbon fiber band, the at least one carbon fiber band coming from a gate is fed to a spreading module via a delivery mechanism. When spreading, the filaments of the at least one carbon fiber ribbon are fanned out.

The expansion module is preferably variably adjustable and also preferably heatable. It is also advantageous if the respective spreading depth can be adjusted in a targeted manner with the spreading module. With the expansion module, the at least one carbon fiber strip is expanded to a defined width. A further delivery mechanism, which is preferably used, pulls the resulting expanded carbon fiber ribbon with high tension through the expansion module and relieves the tension that has built up again by means of a preferably omega-shaped arrangement of the delivery mechanism rollers and a large wrap.

In the at least one narrow, partially unevenly wide carbon fiber ribbon, the carbon fiber filaments are initially present with different tension. When spreading to form the spreading carbon fiber ribbon, the carbon fiber filaments are aligned to form a uniform ribbon with a defined weight per unit area. From this, in the following process steps, particularly fine carbon fiber strands and, in turn, carbon fiber strand sections can be produced.

The strengthening of the spread carbon fiber tape can take place in a non-positive and / or cohesive manner. The spread carbon fiber ribbon is preferably wetted / coated with a wetting agent, for example based on a polymer, for solidification. One speaks here of the so-called coating. Epoxy resins, styrene-butadiene rubber (SBR) and / or selected minerals are particularly suitable as wetting agents. Depending on the selected wetting agent and its processing properties, various processes can be used for continuous application to the spread carbon fiber ribbon.

Advantageously, the spread carbon fiber tape is consolidated into a spread and solidified carbon fiber tape by applying at least one fluid used as a wetting agent or by immersing the spread carbon fiber tape in at least one fluid and subsequent drying and / or hardening of the spread carbon fiber tape provided with the fluid.

The fluid can, for example, be applied to the spread carbon fiber tape via a roller. It is advantageous if the fluid can be dosed precisely and is applied with a high degree of penetration.

Alternatively, the fluid can be sprayed onto the spread carbon fiber ribbon by means of a spray head. Here, too, very precise dosing is possible, and the non-contact application minimizes system contamination.

Another alternative is to convey the spread carbon fiber ribbon through an immersion bath that contains the fluid. With this variant, complete wetting of the spread carbon fiber strip with the fluid can advantageously take place.

In another embodiment, the spread carbon fiber ribbon is wetted on one side with fluid by means of a rotating roller immersed on one side in an immersion bath containing the fluid, which rotates and removes the fluid from the immersion bath and wets the expanded carbon fiber ribbon guided over the roller with this entrained fluid.

The solidification of the expanded carbon fiber band ensures a clean, reproducible separation process of the expanded and solidified carbon fiber band.

In a preferred embodiment of the invention, the spread and solidified carbon fiber ribbon is cut into several parallel carbon fiber strands along the fiber processing direction.

The longitudinal cutting converts the spread and solidified carbon fiber ribbon into adjacent carbon fiber strands with the required fineness (100 tex ≤ Tt ≤ 200 tex). Provided that a carbon fiber heavy tow (50 k, 3300 tex) can be expanded reproducibly to an advantageous width of 50 mm, a cutting width b per track of 1.5 mm ≤ results for the longitudinal severing of the expanded and solidified carbon fiber ribbon b ≤ 3 mm (for 100 tex ≤ Ttziel ≤ 200 tex). A clean cutting process must be guaranteed to produce such narrow strips of tape. This poses particularly great challenges with regard to tool wear when cutting through cross-running carbon fibers.

• Zum einen kann das gespreizte und verfestigte Carbonfaserband über wenigstens eine ortsfeste Klinge geführt werden. Hier ist das Durchtrennen ein Durchschneiden. Diese Realisierung ist besonders kostengünstig.

Various methods can be used for this mechanical separation process:

• On the one hand, the spread and solidified carbon fiber tape can be guided over at least one stationary blade. Here the severing is a cutting through. This implementation is particularly cost-effective.

Alternatively, the spread and solidified carbon fiber ribbon can be guided over at least one rotating circular knife for its longitudinal severing and thus also be cut longitudinally. With this method, tool wear is less and only low cutting forces act.

Another possibility of severing is to convey the spread and solidified carbon fiber ribbon via an ultrasonic blade with an alternating up-and-down movement relative to the carbon fiber ribbon. Advantageously, only small cutting forces act here.

In order to produce the carbon fiber strand sections, the carbon fiber strands running along the fiber processing direction are to be cut through to the desired fiber length after being cut longitudinally, transversely to the fiber orientation. To ensure high plant productivity, this should be done without interrupting the continuous process. One speaks here of the so-called cut on the fly.

Various processes can be used for the mechanical cutting process across the grain.

On the one hand, the severing can take place by means of at least one blade which, in the manner of a guillotine, exerts alternating movements across the carbon fiber strands. Here the lengthways cut carbon fiber strands are cut across. This implementation is inexpensive.

Alternatively, the cutting through of the carbon fiber strands can be carried out by means of at least one circular knife which exerts alternating movements across the carbon fiber strands. This implementation is advantageously associated with low tool wear.

Another possibility is to cut through the carbon fiber strands using a continuously rotating knife shaft. In this continuous cutting process, there is advantageously no relative movement between the cutting edge and the carbon fiber strands.

The carbon fiber strand sections preferably have a width of 5 mm to 50 mm.

It is particularly favorable if the spread and solidified carbon fiber tape or the carbon fiber strands or the carbon fiber strand sections is or are dried and polymerized or mineralized.

The carbon fiber strand sections are advantageously separated by such post-processing, which has the effect that they do not form any agglomerates in the later composite material. The flowability of a curable material which contains the carbon fiber strand sections according to the invention is therefore not adversely affected, and an almost homogeneous fiber distribution is achieved.

In a preferred embodiment, additives are applied to the carbon fiber strand sections, which ensure optimal adhesion between the fibers and the curable material in the composite material.

The post-processing of the carbon fiber strand sections by drying and polymerizing or mineralizing depends to a large extent on the selected polymer-based system for consolidation. Therefore, post-processing can optionally be integrated in the process chain after the solidification process step. This can be advantageous if, for example, an adhesive carbon fiber tape cannot be optimally separated during the separation process. If necessary, additional material drying and / or hardening can take place after solidification.

In a preferred embodiment of the invention, the at least one carbon fiber ribbon has a fineness of 800 800 tex and the at least one carbon fiber ribbon is expanded to form the expanded carbon fiber ribbon at least doubling the respective width. A fineness of 800 tex corresponds to a 12k carbon fiber roving, i.e. a carbon fiber roving with 12,000 filaments.

In principle, in the present invention, carbon fiber ribbons with a lower number of filaments and thus a lower fineness, such as, for example, 1 k carbon fiber rovings which only have 1000 filaments, can be used. However, these are correspondingly more expensive than carbon rovings with a higher number of filaments. The present invention, on the other hand, offers the advantage that carbon fiber tapes with a higher number of filaments can easily be used as the starting material and can thus be produced more cost-effectively, since the at least one carbon fiber tape and thus its filaments are spread open in the process and subsequently cut.

Particularly suitable for the at least one carbon fiber tape in the present invention are so-called heavy tows, that is to say carbon fiber rovings with a number of filaments of more than 24 k, which are offered more cost-effectively than carbon fiber rovings with a smaller number of filaments.

The use of, for example, 50 k carbon fiber rovings (that is to say with 50,000 filaments) or carbon fiber rovings with an even greater number of filaments, which are used as carbon fiber ribbons or as starting material for the method according to the invention, is particularly suitable. 50 k - carbon fiber rovings typically have a fineness of 3400 tex.

However, it is also possible to use several carbon rovings or carbon fiber tapes as the starting material for the method according to the invention. For example, instead of a 50 k carbon fiber roving, 2 x 25 k carbon fiber rovings or 4 x 12.5 k carbon fiber rovings can be used as the starting material of the process, that is to say as the at least one carbon fiber ribbon.

The object is also achieved by a method for reinforcing components, in which, using an embodiment of the method described above, carbon fiber strand sections are produced and introduced into a hardenable material.

In this process, the carbon fiber strand sections are preferably introduced into fresh concrete, fresh mortar, liquid bitumen, liquid tar and / or liquid plastic.

Advantageously, by introducing the carbon fiber strand sections into a curable material, an increase in the mechanical strengths of the curable material and, with regard to concrete applications, a reduction in crack propagation in the event of component failure can be achieved.

The carbon fiber strand sections formed from the at least one carbon fiber ribbon or carbon fiber roving, each of which - like the original carbon fiber ribbon - have high rigidity and strength in the longitudinal direction of the fibers, are present in the curable material in a disordered manner. Due to the mixing of the carbon fiber strand sections with the curable material, the carbon fiber strand sections are also later in a disordered arrangement in the cured material composite formed from the curable material and the carbon fiber strand sections introduced therein, which has the effect that their rigidity and strength have an effect in all spatial directions of the cured material composite . This means that a Cured composite material produced component are advantageously highly mechanically stressed in all spatial directions.

By using carbon fiber strand sections as reinforcement, the building can be built much more filigree, the drying time is much shorter and the distribution of the reinforcement, for example in concrete, is much more homogeneous and does not have to be fixed in advance at the appropriate point. This enables a higher flexibility as well as a significant reduction of the preparation effort for the introduction and fixation with a simultaneous reduction of conventional steel reinforcement in the concrete processing and a greater design variety in the component design.

• - ein Carbonfaserbandbereitstellungsmodul zum Bereitstellen wenigstens eines Carbonfaserbandes;
• - ein Spreizmodul mit beheizten, entlang ihres Umfangs unstrukturierten Spreizstäben zum Aufspreizen des wenigstens einen Carbonfaserbandes zu wenigstens einem gespreizten Carbonfaserband;
• - wenigstens ein Verfestigungsmodul zum Verfestigen des wenigstens einen gespreizten Carbonfaserbandes zu wenigstens einem gespreizten und verfestigten Carbonfaserband;
• - ein Längstrennmodul zum Durchtrennen des wenigstens einen gespreizten und verfestigten Carbonfaserbandes längs der Faserverarbeitungsrichtung in mehrere parallele Carbonfaserstränge;
• - ein Quertrennmodul zum Durchtrennen der Carbonfaserstränge quer zu der Faserverarbeitungsrichtung in Carbonfaserstrangabschnitte; und
• - wenigstens eine einen durchgehenden Materialtransport von dem Carbonfaserbandbereitstellungsmodul bis zu dem Quertrennmodul ermöglichende Materialfördereinrichtung

aufweist.The object is also achieved by a carbon fiber strand section production device, which one after the other in a fiber processing direction

• - A carbon fiber band supply module for providing at least one carbon fiber band;
• a spreading module with heated spreading bars unstructured along their circumference for spreading the at least one carbon fiber band to form at least one spread carbon fiber band;
• - At least one consolidation module for consolidating the at least one expanded carbon fiber band to form at least one expanded and consolidated carbon fiber band;
• - A longitudinal cutting module for cutting the at least one spread and solidified carbon fiber band along the fiber processing direction into several parallel carbon fiber strands;
• - A transverse cutting module for cutting the carbon fiber strands transversely to the fiber processing direction into carbon fiber strand sections; and
• - At least one material conveying device that enables continuous material transport from the carbon fiber band supply module to the transverse cutting module

having.

The carbon fiber tape provision module preferably ensures a rotation-free provision of the carbon fiber tape. This is ensured in particular by a tangential take-off with a specific tensile stress of the at least one carbon fiber strip from a spool. The carbon fiber sliver supply module is particularly preferably an electronically controlled gate. The carbon fiber band supply module can additionally have fiber guide elements for an optimal withdrawal of the at least one carbon fiber band.

To spread open the at least one carbon fiber band to form a spread carbon fiber band, the at least one carbon fiber band coming from the gate is preferably fed to a spreading module via a delivery mechanism.

The expansion module preferably has a plurality of deflection rods whose height and / or temperature can be adjusted independently of one another. The spreading depth can thus advantageously be adjusted in a targeted manner.

The at least one carbon fiber band is spread out to a defined width in the spreading module. The at least one carbon fiber band is preferably spread to the maximum extent.

A delivery mechanism with an omega-shaped belt course is preferably arranged between the expansion module and the consolidation module, which pulls the carbon fiber ribbon with high tension through the expansion module and relieves the built-up tension through the omega-shaped arrangement of the delivery mechanism rollers and a large wrap.

The strengthening of the spread carbon fiber tape in the strengthening module can take place in a non-positive and / or cohesive manner. In this context, the expression “solidified” in the present invention does not mean that an end solidification, for example drying and / or hardening of a wetting agent applied to the spread carbon fiber ribbon, must already be present. Such drying and / or hardening can also take place subsequently.

The spread carbon fiber tape is preferably wetted / coated in the consolidation module with a wetting agent, usually based on polymers, a so-called coating takes place. Epoxy resins, styrene-butadiene rubber (SBR) or selected minerals are particularly suitable as wetting agents. Depending on the selected wetting agent and its processing properties, there are various methods of continuous or discontinuous application to the spread carbon fiber ribbon.

The spread carbon fiber band is advantageously solidified by applying at least one fluid or by immersing the spread carbon fiber band in at least one fluid.

In particular, the solidification module can have a coating module, a spray module or an immersion bath. It is also useful if the solidification module has a drying and / or curing unit that adjoins the coating module, the spray module or the immersion bath.

Advantageously, the solidification of the expanded carbon fiber band in the solidification module ensures a clean, reproducible separation process of the expanded and solidified carbon fiber band in the further course of the process.

The longitudinal cutting module preferably has at least one first cutting device which cuts the spread and solidified carbon fiber ribbon along the fiber processing direction into several parallel carbon fiber strands.

The first cutting device can have at least one standing blade, at least one rotating circular knife, at least one ultrasonic cutting edge with an alternating up-and-down movement, or a combination of the aforementioned.

The transverse cutting module preferably has at least one second cutting device which cuts the carbon fiber strands transversely to the fiber processing direction into carbon fiber strand sections, that is to say so-called carbon fiber sticks.

The second cutting device can have at least one blade, at least one rotating circular knife and / or at least one continuously rotating knife shaft.

The object is also achieved by a component production device which has an embodiment of the above-described carbon fiber strand section production device and a matrix material supply module connected to the carbon fiber strand section production device via a conveying device.

As a result, the produced carbon fiber strand sections can advantageously be introduced into a hardenable material immediately after their production, which material is provided by the matrix material supply module.

The matrix material supply module preferably produces and / or contains fresh concrete, fresh mortar, liquid bitumen, liquid tar and / or liquid plastic.

The invention makes it possible to provide carbon fiber strand sections which can be distributed with maximum homogenization in a curable material. The production of the carbon fiber strand sections from at least one carbon fiber ribbon with a fineness of ≥ 800 tex is also inexpensive and effective.

Advantageously, by introducing the carbon fiber strand sections into a curable material, an increase in the mechanical strengths of the curable material and, with regard to concrete applications, a reduction in crack propagation in the event of component failure can be achieved.

By using carbon fiber strand sections as reinforcement, the building can be built much more filigree, the drying time is much shorter and the distribution of the reinforcement, for example in concrete, is much more homogeneous and does not have to be fixed in advance at the appropriate point. This enables a higher flexibility as well as a significant reduction of the preparation effort for the introduction and fixation with a simultaneous reduction of conventional steel reinforcement in the concrete processing and a greater design variety in the component design.

The invention is explained in more detail below with reference to exemplary embodiments and associated figures, without being restricted to these.

• 1 eine schematische Seitenansicht einer zur Ausführung des erfindungsgemäßen Verfahrens geeigneten erfindungsgemäßen Bauteilherstellungsvorrichtung;
• 2a eine schematische Detailansicht eines in der vorliegenden Erfindung verwendbaren Verfestigungsmoduls;
• 2b eine schematische Detailansicht eines alternativ in der vorliegenden Erfindung einsetzbaren Verfestigungsmoduls;
• 2c eine schematische Detailansicht eines weiteren alternativen, in der vorliegenden Erfindung verwendbaren Verfestigungsmoduls;
• 2d eine schematische Detailansicht noch eines weiteren alternativen, in der vorliegenden Erfindung verwendbaren Verfestigungsmoduls;
• 3a eine schematische Detailansicht eines in der vorliegenden Erfindung verwendbaren Längstrennmoduls;
• 3b eine schematische Detailansicht eines alternativen, in der vorliegenden Erfindung verwendbaren Längstrennmoduls;
• 3c eine schematische Detailansicht eines weiteren alternativen in der vorliegenden Erfindung nutzbaren Längstrennmoduls;
• 4a eine schematische Detailansicht eines in der vorliegenden Erfindung verwendbaren Quertrennmoduls;
• 4b eine schematische Detailansicht eines alternativen, in der vorliegenden Erfindung verwendbaren Quertrennmoduls; und
• 4c eine schematische Detailansicht eines weiteren alternativen, in der vorliegenden Erfindung einsetzbaren Quertrennmoduls.

Show it:

• 1 a schematic side view of a component manufacturing device according to the invention suitable for carrying out the method according to the invention;
• 2a a schematic detailed view of a consolidation module that can be used in the present invention;
• 2 B a schematic detailed view of a consolidation module which can alternatively be used in the present invention;
• 2c a schematic detailed view of a further alternative, usable in the present invention consolidation module;
• 2d a schematic detailed view of yet another alternative, usable in the present invention consolidation module;
• 3a a schematic detailed view of a longitudinal dividing module which can be used in the present invention;
• 3b a schematic detailed view of an alternative longitudinal separating module which can be used in the present invention;
• 3c a schematic detailed view of a further alternative longitudinal dividing module that can be used in the present invention;
• 4a a schematic detailed view of a transverse separation module which can be used in the present invention;
• 4b a schematic detailed view of an alternative, usable in the present invention transverse separation module; and
• 4c a schematic detailed view of a further alternative transverse separation module that can be used in the present invention.

1 shows a side view of a component manufacturing device according to the invention which is suitable for carrying out the method according to the invention.

The illustrated component production device essentially comprises a carbon fiber strand section production device 10 and a matrix delivery module 9 on.

The fiber processing direction A is indicated by arrows.

The carbon fiber hank cut manufacturing apparatus 10 has a carbon fiber sliver supply module in the fiber processing direction A one after the other 2 , a spreading module 3rd , a consolidation module 4th , a longitudinal cutting module 5 , a cross-cut module 6th and a post-processing module 7th on.

Through the carbon fiber tape supply module 2 is at least one carbon fiber tape 1.1 , i.e. a carbon fiber roving, provided without rotation. Such a carbon fiber roving typically has an elliptical or rectangular cross section, but can also have a round cross section. The carbon fiber tape 1.1 consists of essentially parallel carbon filaments. However, some of these carbon filaments can also lie transversely. The carbon fiber tape 1.1 has a filament count of at least 24,000 filaments in the exemplary embodiment shown.

The provision of the carbon fiber tape 1.1 takes place by means of a tangential pull-off with a constant tension from a spool 2 , which is part of an electronic gate in the embodiment shown here.

At least one carbon fiber tape 1.1 is used by the carbon fiber tape supply module 2 coming via a supplier to a spreading module 3rd fed, in which it becomes a spread carbon fiber ribbon 1.2 is spread open. The spreading module 3rd has several deflecting rods whose height and / or temperature can be adjusted independently of one another, whereby the spreading depth can be adjusted in a targeted manner.

The spread carbon fiber tape 1.2 is in a consolidation module 4th to a spread and solidified carbon fiber tape 1.3 solidified. The spread carbon fiber tape 1.2 is used for consolidation in the consolidation module 4th preferably wetted / coated with a wetting agent, usually based on polymers, preferably a fluid. Epoxy resins, styrene-butadiene rubber (SBR) or selected minerals are particularly suitable as wetting agents.

The consolidation of the spread carbon fiber tape 1.2 is important for the further conduct of the procedure. As a result, the fibers of the spread carbon fiber ribbon form a mechanically resilient composite despite the spreading, so that defined longitudinal and transverse cutting is possible, as well as the carbon fiber strands that are produced 1.4 as well as the carbon fiber strand sections produced from it 1.5 even if later turned into a hardenable material 9 are introduced and mixed with this, have sufficient inherent strength.

The spread and solidified carbon fiber tape 1.3 is then placed in a longitudinal cutting module 5 along the fiber processing direction into several parallel carbon fiber strands 1.4 severed. The carbon fiber strands 1.4 are cut in a defined width. The carbon fiber strands 1.4 are also known as carbon fiber strands.

The cutting is in the 1 indicated by a scissors symbol. The lengthwise cutting of the spread and solidified carbon fiber tape 1.3 takes place in the embodiment shown with a defined cutting width b per track. The cutting width b is preferably in a range of 1.5 mm b 3 mm.

The carbon fiber strands 1.4 are then placed in a cross-cut module 6th without interrupting the continuous process across the fiber orientation in carbon fiber strand sections 1.5 , i.e. into cut carbon fiber strands, which are also called carbon fiber sticks. The cutting is in the 1 indicated by a scissors symbol. The carbon fiber strand sections produced 1.5 have a defined length.

In a post-processing module 7th are the carbon fiber strand sections 1.5 dried and polymerized or mineralized. The carbon fiber strand sections are advantageously 1.5 separated by such post-processing, which causes that they do not form agglomerates in the later composite material.

The post-processing of the carbon fiber strand sections 1.5 by drying and polymerizing or mineralizing is highly dependent on the selected polymer-based system for solidification. Therefore, post-processing can optionally be in the process chain after the consolidation module 4th to get integrated. This can be advantageous if, for example, an adhesive, spread and solidified carbon fiber strand 1.3 cannot be optimally separated during the separation processes. If necessary, additional material drying / hardening can take place after solidification.

The carbon fiber strand section production device is via a conveying device 10 with a matrix material supply module 9 connected in such a way that the carbon fiber strand sections 1.5 into a through the matrix material supply module 9 provided curable material are introduced. The matrix material supply module 9 produces and / or contains fresh concrete, fresh mortar, liquid bitumen, liquid tar and / or liquid plastic.

The carbon fiber strand sections produced can advantageously 1.5 are introduced into the curable material immediately after their production. Advantageously, by introducing the carbon fiber strand sections 1.5 In a hardenable material, an increase in the mechanical strengths of the hardenable material and, in relation to concrete applications, a reduction in crack propagation in the event of component failure can be achieved.

The 2a to 2d each show a detailed view of usable embodiments of the consolidation module 4th . The fiber processing direction is indicated in each case by an arrow. It is always the one in the consolidation module 4th spread carbon fiber tape guided in 1.2 and that from the consolidation module 4th spread out and solidified carbon fiber tape 1.3 to recognize.

In the in 2a shown variant of the consolidation module 4th in the form of a flow discharge coating module 4a becomes a fluid 4.1 from a flow discharge device 4.2 such as a hopper, via a rotating roller 4.3 on the spread carbon fiber tape 1.2 applied. The advantage here is that the fluid 4.1 can be dosed precisely and with a high degree of penetration on the spread carbon fiber ribbon 1.2 is applied.

In the in 2 B shown variant of the consolidation module 4th in the form of a spray module 4b becomes a fluid 4.1 by means of a spray device, such as. B. a spray head 4.4 , on the spread carbon fiber tape 1.2 sprayed on. Here, too, very precise dosing is possible and the contactless application minimizes system contamination.

In the in 2c shown variant of the consolidation module 4th in the form of an immersion bath 4c becomes the spread carbon fiber tape 1.2 over several conveyor rollers 4.5 by an immersion bath with a fluid 4.1 conveyed completely through and thereby wetted with this on all sides. With this variant, complete wetting of the spread carbon fiber strip can advantageously be achieved 1.2 respectively.

2d shows a schematic detailed view of a further alternative consolidation module 4th in the form of a dip coating module 4d . The spread carbon fiber tape is wetted here 1.2 with a fluid 4.1 on only one side of the spread carbon fiber tape 1.2 . For this the spread carbon fiber tape 1.2 using conveyor rollers 4.5 on top of a rotating roller 4.6 guided while moving a bottom of this rotating roller 4.6 in a bath with the fluid provided therein 4.1 is located. By rotating the role 4.6 becomes the fluid 4.1 taken up and the underside of the spread carbon fiber tape 1.2 with the fluid 4.1 wetted.

The 3a to 3c each show a detailed view of a longitudinal dividing module 5 . The fiber processing direction is indicated in each case by an arrow. It is always the one in the longitudinal separation module 5 spread and solidified carbon fiber tape guided in 1.3 and the one from the longitudinal separation module 5 led out parallel carbon fiber strands 1.4 to recognize.

In the in 3a The variant shown is the spread and solidified carbon fiber tape 1.3 via a fixed blade 5.1 guided. This implementation is particularly cost-effective.

In the in 3b The variant shown is the spread and solidified carbon fiber tape 1.3 via a rotating circular knife 5.2 guided. Advantageously, the tool wear is less with this method and only low cutting forces act.

In the in 3c The variant shown is the spread and solidified carbon fiber tape 1.3 via an ultrasonic blade 5.3 guided with alternating up-down movement. Advantageously, only small cutting forces act here.

The 4a to 4c each show a detailed view of a transverse separation module 6th . The Fiber processing direction is indicated in each case by an arrow. There are always those in the cross-cut module 6th in led parallel carbon fiber strands 1.4 and the one from the cross-cut module 6th led out carbon fiber strand sections 1.5 to recognize.

In the in 4a In the variant shown, the parallel carbon fiber strands are severed 1.4 by means of a blade 6.1 which, in the manner of a guillotine, produce alternating movements across the carbon fiber strands 1.4 exercises. This implementation is advantageously inexpensive.

In the in 4b The variant shown is cut by means of a circular knife 6.2 , which alternates movements across the carbon fiber strands 1.4 exercises. This implementation advantageously has low tool wear.

In the in 4c The variant shown is the severing of the carbon fiber strands 1.4 by means of a continuously rotating knife shaft 6.3 . In this continuous cutting process, there is advantageously no relative movement between the cutting edge and the carbon fiber strands 1.4 .

QUOTES INCLUDED IN THE DESCRIPTION

This list of the documents listed by the applicant was 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.

Patent literature cited

• EP 0881312 A2 [0011]
• EP 1788146 B1 [0012]
• DE 102005052660 B3 [0013]
• WO 2011142990 A1 [0013]
• DE 102007012607 B4 [0013]
• DE 102009056197 A1 [0013]
• DE 102015206389 A1 [0015]

Claims (11)

A method for producing carbon fiber strand sections (1.5), characterized in that the following steps are carried out in the following sequence in a continuous process with a constant web speed: at least one carbon fiber band (1.1) is provided; - The at least one carbon fiber band (1.1) is drawn off in a fiber processing direction (A) and spread by means of heated spreader bars that are unstructured along their circumference to form at least one spread carbon fiber band (1.2); - The at least one spread carbon fiber band (1.2) is solidified to form at least one spread and solidified carbon fiber band (1.3); - The at least one spread and solidified carbon fiber band (1.3) is severed lengthways along the fiber processing direction (A) into several parallel carbon fiber strands (1.4); and - the carbon fiber strands (1.4) are severed transversely to the fiber processing direction (A) to form carbon fiber strand sections (1.5). Procedure according to Claim 1 , characterized in that the spread carbon fiber band (1.2) is solidified by applying at least one fluid (4.1) or immersing the spread carbon fiber band (1.2) in at least one fluid (4.1). Procedure according to Claim 2 , characterized in that the spread and solidified carbon fiber tape (1.3) or the carbon fiber strands (1.4) or the carbon fiber strand sections (1.5) is / are dried and polymerized or mineralized. Method according to one of the preceding claims, characterized in that the at least one carbon fiber tape (1.1) has a fineness of ≥ 800 tex and the at least one carbon fiber tape (1.1) is expanded to form the spread carbon fiber tape (1.2) at least doubling the respective width. Method for reinforcing components, characterized in that, using a method according to at least one of the preceding claims, carbon fiber strand sections (1.5) are produced and introduced into a hardenable material (9). Procedure according to Claim 5 , characterized in that the carbon fiber strand sections (1.5) are introduced into fresh concrete, fresh mortar, liquid bitumen, liquid tar and / or liquid plastic as a hardenable material (9). Carbon fiber strand section production device (10), characterized in that the device (10) in a fiber processing direction (A) in the following sequence one after the other - a carbon fiber tape supply module (2) for supplying at least one carbon fiber tape (1.1); - A spreading module (3) with heated spreading bars unstructured along their circumference for spreading the at least one carbon fiber band (1.1) to form at least one spread carbon fiber band (1.2); - At least one consolidation module (4) for consolidating the at least one expanded carbon fiber band (1.2) to form at least one expanded and consolidated carbon fiber band (1.3); - A longitudinal cutting module (5) for cutting through the at least one spread and solidified carbon fiber band (1.3) along the fiber processing direction (A) into several parallel carbon fiber strand sections (1.4); - A transverse cutting module (6) for cutting the carbon fiber strands (1.4) into carbon fiber strand sections (1.5) transversely to the fiber processing direction (A); and - has at least one material conveying device which enables continuous material transport from the carbon fiber band supply module (2) to the transverse cutting module (6). Carbon fiber strand section manufacturing device (10) according to Claim 7 , characterized in that a delivery mechanism with an omega-shaped belt course is arranged between the expansion module (3) and the consolidation module (4). Carbon fiber strand section manufacturing device (10) according to Claim 7 or 8th , characterized in that the solidification module (4) has a flow discharge coating module (4a), a spray module (4b), an immersion bath (4c) or an immersion coating module (4d). Component manufacturing device, characterized in that the component manufacturing device comprises a carbon fiber strand section manufacturing device (10) according to at least one of the Claims 7 to 9 and a matrix material supply module (9) connected to the carbon fiber strand section production device (10) via a conveying device. Component manufacturing apparatus according to Claim 10 , characterized in that the matrix material supply module (9) produces and / or contains fresh concrete, fresh mortar, liquid bitumen, liquid tar and / or liquid plastic as curable material (9).

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