DE102023203726A1 - REINFORCEMENT UNIT - Google Patents

Abstract

The present invention relates to a reinforcement unit, a concrete component comprising a reinforcement unit and the use of a corresponding reinforcement unit.

Description

SUBJECT OF THE INVENTION

The invention relates to a reinforcement unit, a component comprising the reinforcement unit and the use of the reinforcement unit.

BACKGROUND OF THE INVENTION

Reinforcement (also called armouring) is the strengthening of concrete components, usually with the help of steel inserts. Reinforcement can achieve a particularly high load-bearing capacity of concrete components, in particular by increasing the resistance of the material to tensile stresses. As a rule, reinforcement units such as steel grids are cast into the concrete during component manufacture. Instead of steel, fibre-reinforced structures can also be used, which are particularly preferred due to their generally significantly lower weight, higher strength, better fatigue properties and corrosion resistance. For example, the use of grid-shaped reinforcements made of textile material based on glass fibres is known from the state of the art.

In the EP 0 227 207 B1 discloses a reinforcement unit for use in a concrete structure, which consists of two or more systems of elongated reinforcement elements formed from a textile fiber material. The textile fiber material is embedded in a plastic resin matrix. The reinforcement elements are nested at their crossing points, the crossing sections being press-formed so that they have substantially the same thickness as non-crossing points. In the manufacture of the reinforcement unit, rows of textiles impregnated with a matrix resin material are first stretched between suspensions in order to obtain a lattice-shaped structure. With the aid of a pressure plate, the lattice-shaped structure is pressed together in order to obtain a uniform thickness of the reinforcement unit. After the resin has hardened, the lattice structure is cut off at the suspensions.

The EP 0 227 207 B1 However, the reinforcement unit described has a number of disadvantages. After the resin matrix has hardened, the reinforcement units obtained are no longer meltable and malleable. The shape of the grid must therefore always correspond to the "final" shape intended for the concrete component. In addition, the use of the EP 0 227 207 B1 The disclosed press molding process allows the mold to be adapted when the geometric structure of the grid varies. Recyclability is also not possible due to the use of a duromer matrix resin material. These materials therefore have significant disadvantages in terms of recycling and sustainability. In addition, several reinforcement elements can only be connected to one another using complex and downstream joining processes.

TASK

Against this background, the object of the present invention was therefore to provide a reinforcement unit with which the disadvantages described above can be overcome, which in particular enables a high degree of flexibility and a wide range of applications, and which can be produced in a simple and cost-effective manner.

DESCRIPTION OF THE INVENTION

• ▪ ein Fasermaterial in Form von Endlosfasern, d. h. ein Endlosfasermaterial,
• ▪ ein Matrixmaterial,

wobei das Fasermaterial zumindest teilweise, vorzugsweise vollständig, in das Matrixmaterial eingebettet ist, d. h. dass das Fasermaterial zumindest teilweise, vorzugsweise vollständig, von Matrixmaterial umgeben wird.This object is achieved according to the invention by a reinforcement unit comprising the following components

• ▪ a fibre material in the form of continuous fibres, ie a continuous fibre material,
• ▪ a matrix material,

wherein the fiber material is at least partially, preferably completely, embedded in the matrix material, ie that the fiber material is at least partially, preferably completely, surrounded by matrix material.

The fiber material is preferably substantially embedded in the matrix material. In this context, substantially means that at least 70% by volume of the fiber material is completely surrounded by matrix material, preferably at least 75% by volume, more preferably at least 80% by volume, even more preferably at least 85% by volume, even more preferably at least 90% by volume and most preferably at least 95% by volume. The reinforcement unit can also comprise a plurality of fiber materials made of continuous fibers, in which case the above range information preferably refers to the volume fraction of a fiber material and/or to the sum of the volume fractions of all fiber materials.

According to the invention, the matrix material comprises or consists of a thermoplastic polymer. The matrix material preferably comprises at least 40% by weight of a thermoplastic polymer, more preferably at least 50% by weight, even more preferably at least 75% by weight, even more preferably at least 85% by weight and most preferably at least 90% by weight or even 95% by weight.

The matrix material can also comprise several thermoplastic polymers, in which case the above minimum information refers to the sum of the weight proportions of all thermoplastic polymers. The matrix material can also comprise additives, such as flame-retardant additives, dyes or fillers. Due to the thermoplastic properties of the matrix material, the additive(s) can be easily introduced into the plastic matrix material using a so-called masterbatch. The term masterbatch refers to additives embedded in a plastic matrix in the form of granules in which the additives are present in concentrations that are higher than in the end application. They are mixed into the plastic (raw polymer) to change the properties and enable a high level of process reliability.

The reinforcement unit according to the invention is particularly suitable for use in a component, in particular a concrete component and/or a plaster reinforcement. Other possible uses are as asphalt reinforcement, plant grids or in a ceramic component (in particular for bridging cracks in such a component).

The matrix material of the fiber composite component according to the invention, i.e. the reinforcement unit according to the invention, serves to at least partially, preferably completely embed the fiber material. It holds the fibers of the fiber material in their position and transfers and distributes tensions between them. It also has a protective function, as it protects the fibers from external influences such as UV radiation or weather effects.

The above-described advantages of the invention are maximized by also partially, preferably completely (i.e. over 70% of the surface) or even completely impregnating the individual continuous fibers, i.e. the individual filaments of the fiber material.

The fiber composite component can also comprise pores, ie air and/or gas inclusions, which, however, preferably do not make up more than 5% by volume of the total volume of the fiber composite component. Particularly preferably not more than 3% by volume, even more preferably not more than 2% by volume and most preferably not more than 1% by volume. Fiber and matrix volume fractions as well as the volume fraction of pores can be determined by means of computer tomographic analysis, such as in Willems, Fabian, et al. “Determination of the fiber orientation of long glass fiber reinforced thermoplastics using image-optical analysis and computer tomography” German Society for Non-Destructive Testing eV, Ed (2018 ). For carbon fibre reinforced reinforcement units, the determination of the proportions of matrix material, fibre and voids can also be carried out as described in ISO 14127, first edition, 2008.

Preferably, the matrix material has a substantially homogeneous chemical composition with the exception of one or more optionally incorporated additives and the incorporated fiber material, i.e., with the exception of optionally incorporated additives and the incorporated fiber material, there are no visible material boundaries.

Reinforcement or armouring refers to the strengthening of concrete components to increase the load-bearing capacity. The reinforcement unit according to the invention is a fibre composite component which can be introduced into a concrete component for this purpose. The reinforcement unit comprises one or more reinforcement elements which can be connected to one another, the connection preferably being made in a material-locking manner, in particular by plastic welding of the thermoplastic matrix material. The reinforcement unit preferably has several, preferably elongated, reinforcement elements which are arranged in such a way that they cross one another. The reinforcement elements are particularly preferably connected to one another at the crossing points, the connection preferably being made in a material-locking manner, in particular by plastic welding of the thermoplastic matrix material.

If the reinforcement unit comprises several reinforcement elements that cross each other, the reinforcement unit is preferably designed such that at least the crossing points are substantially, preferably completely, embedded in matrix material.

The reinforcement elements of the reinforcement unit according to the invention preferably have an at least partially, preferably completely, straight, elongated course. In a preferred embodiment, the reinforcement elements have at least partially a course that deviates from a straight course (e.g. an angled one).

In the context of the invention, “continuous fibers” are understood to mean fibers with a length L ≥ 50 mm. The fibers of the fiber material according to the invention preferably have a fiber length L, where L ≥ 75 mm, preferably L ≥ 100 mm, even more preferably L ≥ 500 mm and most preferably L ≥ 1000 mm.

The reinforcement unit according to the invention can be further removed from the continuous fiber material other fiber materials. Preferably, however, ≥ 30 vol.% of the entire fiber material is continuous fibers, more preferably ≥ 50 vol.%, even more preferably ≥ 60 vol.%, even more preferably ≥ 70 vol.%, even more preferably ≥ 80 vol.% and most preferably ≥ 90 vol.%. Most preferably, the entire fiber material of the reinforcement unit consists of continuous fibers.

If the reinforcement unit comprises elongate reinforcement elements, the fibers of the fiber material are preferably designed such that the fibers extend over the entire length of a reinforcement element.

Particularly preferably, the continuous fibers are unidirectional fibers, i.e. the continuous fibers are oriented in a single direction in a reinforcement element and are preferably aligned parallel to one another.

By using a thermoplastic matrix material to embed the fiber material, a particularly high level of flexibility is achieved in the design and adaptation of the reinforcement unit. The thermoplastic polymer material enables welding, for example by ultrasound or laser, which significantly simplifies the structure construction during the manufacture of the reinforcement unit. Crossing points can be very easily obtained by plastic welding and can also be subsequently adjusted. This makes it possible to dispense with complex and sometimes material- and/or cost-intensive joining techniques such as sewing or gluing. In addition, the thermoplastic polymer material can be overmolded or connected to other structures using plastic welding alone, so that complex geometries with high-quality mechanical properties can be easily obtained. The combination of continuous fibers and thermoplastic matrix material also results in particularly advantageous mechanical properties that lead to an increased reinforcement effect. The use of knitted threads to connect several reinforcement elements can also be advantageously avoided. These usually lead to constrictions, which negatively affect the homogeneity of the reinforcement unit and thus its load-bearing capacity. The reinforcement unit particularly preferably has a plurality of elongated reinforcement elements which comprise the fiber and matrix material and which are connected to one another at connection points, e.g. crossing points, wherein at least one, preferably several, particularly preferably all connection points are free of knitting threads. These connection points are particularly preferably connected to one another in a materially bonded manner.

Without significant loss of physical properties, individual reinforcement elements can be reshaped and the geometry of the reinforcement unit can be subsequently adjusted. In addition, the reinforcement unit can be recycled much more easily after use than would be possible when using duromer matrix materials, the components of which cannot be separated without causing damage. The use of the reinforcement unit according to the invention therefore not only enables more universal use, but also better sustainability of the product can be achieved. Since an adjustment of the tool geometry is not necessary, or at least not to the extent that it is necessary when using duromer resins, the use of a thermoplastic matrix material according to the invention also simplifies the manufacturing process and thus generally increases manufacturing speed. In addition, the reinforcement unit according to the invention is characterized by easy machinability for tunnel boring machines, low thermal conductivity and good permeability for radio frequencies.

Due to the corrosion resistance and the very good mechanical properties, the use of the reinforcement unit according to the invention in a concrete component can also significantly reduce the amount of concrete required compared to a reinforced concrete component in order to obtain a comparable stability of the component. This can result in significant _CO2 savings.

In a preferred embodiment of the invention, the thermoplastic polymer is selected from the group consisting of polyamides (PA), in particular PA 6, PA 6.6, PA 4.6, PA 6.10, PA 6.12, PA 11, PA 12, polyphthalamides (PPA), polycarbonate (PC), polyvinyl butyral (PVB), polypropylene (PP), polyethylene (PE), polyesters such as polybutylene terephthalate (PBT), polyethylene terephthalate (PET), polyphenylene sulfide, acrylonitrile butadiene styrene (ABS), polyacrylate, polymethacrylate, polyoxymethylene (POM), polycarbonate (PC), polyethersulfone (PES), polyether ketones such as polyether ether ketone (PEEK) or polyether ketone ketone (PEKK), polyphenyl ether (PEI), polyvinyl chloride (PVC), polylactide, polyurethane, ethylene-vinyl acetate copolymer (EVA), polystyrene (PS), copolymers and/or mixtures of the aforementioned polymers.

Particularly preferred due to their mechanical property profile are polyamides (PA), in particular polyphthalamides (PPA) such as PA6T, PA6T/6I, PA 6T/66, PA9T, PA 6T/6, PA 6T/“DT”, PA6T/X, PA10T/X or PA6T/6I, polycarbonates (PC), polyterephthalates and polyether ketones.

Typically, thermoplastic polymer materials are only used in fiber composite components in combination with short or long fibers. The short fibers are added to the plastic material during the molding process, e.g. injection molding, or are already in the granulate (e.g. long fiber reinforced thermoplastics, LFT) and are distributed essentially homogeneously in the plastic mass to be processed. In contrast, in the present invention, continuous fibers are combined with a thermoplastic matrix material.

Partially crystalline thermoplastic polymers are particularly preferred as matrix material. Partially crystalline thermoplastic polymers are those that have both ordered, crystalline and disordered, amorphous regions in their morphological structure.

The combination of semi-crystalline matrix materials with continuous fibers results in particularly advantageous mechanical properties of the reinforcement unit. In addition, they are more resistant to external influences such as chemicals or weather and have a higher heat resistance. These positive effects are particularly pronounced with a high degree of crystallinity.

Preferably, the degree of crystallinity of the thermoplastic polymer of the reinforcement unit is at least 20%, more preferably at least 30%, even more preferably at least 35% and most preferably at least 40%, but preferably not more than 85%.

Preferably, the degree of crystallinity of the thermoplastic polymer of the reinforcement unit is in a range of 20-90%, more preferably in a range of 30-80%, even more preferably in a range of 35-70%, and most preferably in a range of 35-45%.

The degree of crystallinity can be determined by density measurement or calorimetrically (differential scanning calorimetry). These methods, which are familiar to the expert, are described, for example, in “Macromolecules - Hans-Georg Elias, Hüthig & Wepf Verlag Basel, Heidelberg, 1971”, sections 5.2.2 and 5.2.3.

With the preferred use of continuous fibers in combination with semi-crystalline thermoplastic polymers according to the invention, the inventors were able to observe an increased crystallinity of the thermoplastic matrix material. Without being bound to this theory, the inventors assume that after the fibers have been impregnated during production, the continuous fibers promote nucleation and crystal growth during the subsequent cooling of the matrix material. The use of semi-crystalline thermoplastic polymers is therefore particularly advantageous.

In a preferred embodiment of the invention, the fiber material is present at least in sections, preferably completely, in a higher-level textile structure, i.e. a linear, planar and/or spatial structure made from the continuous fibers. The fiber material is partially, substantially (i.e. over 90% by volume), or even completely embedded in the thermoplastic matrix material.

Particularly preferably, the textile structure is selected from the group consisting of scrims, knitwear, woven fabrics, braids and mixtures thereof.

For the purposes of the invention, braiding is understood to mean the regular intertwining of several strands of flexible material. The difference to weaving is that in braiding the threads are not fed at right angles to the main product direction.

According to the invention, a fabric is understood to be a textile structure that consists of two thread systems, warp (warp threads) and weft (weft threads), which, when viewed on the fabric surface, cross in a pattern at an angle of exactly or approximately 90°. Each of the two systems can be made up of several types of warp or weft (e.g. ground, pile and filling warp; ground, binding and filling weft). The warp threads run in the lengthwise direction of the fabric, parallel to the fabric edge, and the weft threads run in the crosswise direction, parallel to the fabric edge. The threads are connected to the fabric primarily by friction. In order for a fabric to be sufficiently slip-resistant, the warp and weft threads usually have to be woven relatively tightly. Therefore, with a few exceptions, the fabrics also have a closed appearance. This definition corresponds to the standard DIN 61100, Part 1.

According to the invention, the term fabric also includes textile materials that have been tufted. Tufting is a process in which yarns are anchored into a fabric using a machine powered by compressed air and/or electricity.

According to the invention, knitwear is understood to mean textile materials that are made from thread systems by forming stitches. This includes both crocheted and knitted materials.

According to the invention, a scrim is understood to mean a structure that consists of one or more layers of parallel, stretched threads. The threads are usually fixed at the crossing points. The fixation takes place either by material bonding or mechanically by friction and/or form-fitting. The scrim is preferably selected from a monoaxial or unidirectional, a biaxial or multiaxial scrim.

In a preferred embodiment of the invention, the fiber material is in the form of continuous fibers, preferably as rovings in the reinforcement unit, i.e. the continuous fibers form one or more rovings.

The reinforcement unit preferably comprises a plurality of reinforcement elements, each of which comprises one or more rovings which are at least partially, preferably completely, embedded in the thermoplastic polymer material. Such reinforcement elements impregnated with the thermoplastic polymer material are preferably designed in the form of elongated elements and are referred to as "rods" when they comprise exactly one roving. They preferably have a substantially round cross-section, the diameter of the cross-section of the rods being in a range from 1 to 5 mm, preferably 1.5 to 3 mm and particularly preferably 2 to 2.5 mm.

Preferably, the number of individual filaments of the one or more rovings is ≥ 40,000, preferably ≥ 50,000. By using a correspondingly high number of individual filaments (so-called "heavy tows"), the use of several individual rovings for the production of a single reinforcement element can be dispensed with, i.e. the number of rovings to be used can be reduced. This means that smaller creels can be used in the manufacturing process, so that the manufacturing process can be carried out much more simply, more stably and with a higher output. Reinforcement elements with rovings with the high number of individual filaments described above are easier to process and therefore particularly cost-effective.

Particularly preferably, some of the reinforcement elements, preferably all of the reinforcement elements, consist of so-called “rebars” (= reinforcing bars). These are elongated elements that comprise two or more rovings. These rebars preferably have a substantially round cross-section, the diameter of the cross-section of the rebars being in a range from 1 to 25 mm, preferably 2 to 15 mm and particularly preferably 3 to 12 mm. Rebars and rods can be obtained by pultrusion processes.

Preferably, the rebars have an elastic modulus of ≥ 50 GPa, preferably ≥ 60 GPA, more preferably ≥ 75 GPa, even more preferably ≥ 90 GPa and most preferably ≥ 100 GPa. The elastic modulus can be determined as described in DIN EN ISO 527-1.

Preferably, the rebars have a tensile strength ≥ 1000 MPa, preferably ≥ 1200 MPA, more preferably ≥ 1300 MPa, even more preferably ≥ 1400 MPa and most preferably ≥ 1500 MPa. The tensile strength can be determined as described in DIN EN ISO 527-1.

Particularly preferably, some of the reinforcement elements, preferably all of the reinforcement elements, consist of a combination of “rebars” and “rods”.

Rods and rebars, especially when arranged in the form of a grid, preferably have a surface profile. The surface profile can, for example, have a ribbed or wave-shaped geometry. This leads to improved anchoring after the reinforcement unit has been incorporated into the concrete.

Preferably, the reinforcement unit has a plurality of elongate reinforcement elements, wherein at least some of the reinforcement elements are arranged in the form of a group of parallel reinforcement elements. Preferably, the reinforcement unit has at least two groups of reinforcement elements, wherein the reinforcement elements from different groups do not run parallel to one another.

An arrangement in the form of a grid is particularly preferred, wherein the elongated reinforcement elements that form the grid are preferably rods and/or rebars. Such arrangements are also referred to as construction carbon mats or carbon concrete mats in analogy to construction steel mats or reinforcing steel mats.

An arrangement in the form of a reinforcement cage is also particularly preferred.

Preferably, the fiber material is selected from the group consisting of glass fibers, carbon fibers, ceramic fibers, basalt fibers, boron fibers, steel fibers, polymer fibers such as synthetic fibers, in particular aramid and nylon fibers, or natural fibers, in particular natural polymer fibers or combinations of the aforementioned. Particularly preferred are glass fibers and carbon fibers or combinations of the above. Due to their advantageous mechanical properties and low density, carbon fibers are the most preferred. Glass fibers are particularly preferred when electrical conductivity is to be minimized.

Natural fibers are fibers that come from natural sources such as plants, animals or minerals and can be used directly without further chemical conversion reactions. Examples of these according to the invention are flax, jute, sisal or hemp fibers as well as protein fibers or cotton. Regenerated fibers, i.e. fibers that are produced from naturally occurring, renewable raw materials using chemical processes, can also be used according to the invention.

Corresponding fiber materials are characterized by improved recyclability and thus a particularly high level of sustainability.

In a preferred embodiment of the invention, the reinforcement unit has a plurality of elongated reinforcement elements, e.g. in the form of rods, which comprise the fiber and matrix material and which are arranged and aligned in such a way that they are connected to one another at connection points. The connection points can, for example, be crossing points at which the reinforcement elements cross. The reinforcement unit can have further components, e.g. coatings or connecting means, away from these reinforcement elements, which can also comprise the fiber and matrix material.

• ▪ ein Fasermaterial in Form von Endlosfasern,
• ▪ ein Matrixmaterial,

wobei das Fasermaterial zumindest teilweise, vorzugsweise vollständig, in das Matrixmaterial eingebettet ist, und wobei das Matrixmaterial ein thermoplastisches Polymer umfasst oder aus diesem besteht. Faser- und Matrixmaterial können die in den Ansprüchen definierten Eigenschaften und Ausprägungen aufweisen.The invention also includes a system, ie the spatial juxtaposition of functionally coordinated individual components, for producing a reinforcement unit comprising several elongated reinforcement elements, comprising

• ▪ a fibre material in the form of continuous fibres,
• ▪ a matrix material,

wherein the fiber material is at least partially, preferably completely, embedded in the matrix material, and wherein the matrix material comprises or consists of a thermoplastic polymer. Fiber and matrix material can have the properties and characteristics defined in the claims.

Particularly preferably, the reinforcement unit has a lattice shape at least in sections, preferably completely. This makes it possible to achieve particularly uniform reinforcement of a concrete component.

The use of a thermoplastic matrix material according to the invention makes it possible for the reinforcement elements to be initially manufactured individually and even spatially and/or temporally separated and then to be connected to one another in a material-locking manner without the use of further components. The material-locking connection at contact points, in particular crossing points, can be achieved by melting, for example by ultrasonic welding. Since additional joining agents such as adhesives or binding threads can be dispensed with, production is not only particularly simple, the connection of the individual reinforcement elements achieved is also particularly strong. The reinforcement units obtained from this subsequently have particularly advantageous mechanical properties. In addition, the connection points can always be reshaped, i.e. the elements of the reinforcement unit can be "set" again. This makes it possible to adapt the geometry directly before insertion into the concrete component. By separating the connection points, the grid can also be used in a different way later. The contact points can also be press-formed so that they have essentially the same thickness as the non-crossing sections of the reinforcement unit.

The invention preferably also relates to a forming method of reinforcing elements according to the invention by melting and subsequent cooling and optionally materially connecting several reinforcing elements by contacting in the melted state.

The matrix material of the protective device according to the invention can further comprise one or more additives.

A particularly preferred additive is a flame retardant, which is preferably selected from the group consisting of halogenated and/or nitrogen-based flame retardants, inorganic flame retardants such as graphite salts, aluminum trihydroxide, antimony trioxide, ammonium polyphosphate, aluminum diethylphosphinate, mica, muscovite, guanidines, triazines, sulfates, borates, cyanurates, salts thereof and mixtures thereof. In this way, flame retardant activity can be achieved.

In other preferred embodiments, the additive is selected from the group consisting of antioxidants, light stabilizers, in particular UV stabilizers, plasticizers, foaming agents, electrical conductors, heat conductors, dyes, fillers for improving the mechanical properties such as impact modifiers or rubber or thermoplastic particles as well as mixtures of the aforementioned.

The additive can be dissolved or dispersed in the matrix material. If it is dispersed, it is preferably in the form of a powder, flakes, tubes or mixtures of the aforementioned forms.

If the additive is a flame retardant, it is preferably selected from the group of active, i.e. cooling, flame retardants or from the group of passive, i.e. insulating, flame retardants. The flame retardant is particularly preferably an intumescent flame retardant.

Finally, the matrix materials according to the invention can also contain wetting agents. Wetting agents are surface-active substances that usually have a hydrophobic and a hydrophilic molecular part. A distinction is made between non-ionic, anionic and cationic wetting agents. Wetting agents reduce the viscosity of the thermoplastic polymer during its processing. This enables the penetration of the fiber material to be improved, which ultimately leads to a stronger bond between the fiber material and the matrix material.

Examples of non-ionic wetting agents are esters and amides of fatty acids (saturated or unsaturated carboxylic acids, which generally have 4 to 26 carbon atoms in the molecule), fatty amines (primary amines, which generally have 6 to 22 carbon atoms in the molecule) or polyethylene glycol ethers or polypropylene glycol ethers of alcohols, alkylphenols or fatty acid alkanolamides. Examples of anionic wetting agents are salts of alkylmalonic or alkylsuccinic acid, alkylsulfonates, fatty acid ester sulfonates, perfluorinated alkylsulfonates or sulfated fatty acid amides. Cationic wetting agents are substances such as fatty amine salts, salts of alkylenediamines and polyamines, alkylbenzylammonium salts or alkylpyridinium salts.

In a preferred embodiment, the volume ratio of matrix material to fiber material in the reinforcement unit is 3:1 to 1:3, preferably 2:1 to 1:2 and particularly preferably 1.5:1 to 1:1.2.

In a preferred embodiment, the fiber volume fraction of the reinforcement unit is in a range of 35 to 70 vol.%, preferably 35 to 55 vol.%, more preferably 40 to 50 vol.%, and most preferably 45 to 50 vol.%.

In a preferred embodiment, the matrix volume fraction of the reinforcement unit is in a range of 25 to 65 vol.%, preferably 45 to 65 vol.%, more preferably 45 to 60 vol.% and most preferably 50 to 55 vol.%. In the above range limits, the inventors were able to determine a particularly pronounced reinforcing effect.

In a preferred embodiment, the volume ratio of matrix material to additive in the reinforcement unit is 400:1 to 20:1, preferably 200:1 to 50:1 and particularly preferably 150:1 to 75:1.

In a preferred embodiment, the weight proportion of optional additive to the total mass of the fiber composite component, i.e. the reinforcement unit, is 0.05 to 30 wt.%, preferably 0.1 to 20 wt.%, more preferably 0.3 to 15 wt.%, even more preferably 0.5 to 10 wt.%, and most preferably 0.5 to 1 wt.%.

In a preferred embodiment, the weight proportion of optional additive is ≤ 1 wt.%. A low content has a positive effect on the mechanical properties of the fiber composite component, i.e. the reinforcement unit.

The reinforcement unit preferably comprises a coating which preferably contains a flame retardant. This allows the effect of the flame on the matrix and/or the fiber material to be kept as low as possible and thus, in the event of a fire, a long-lasting high stability of the component equipped with the reinforcement unit according to the invention can be achieved.

The coating preferably comprises an aerogel, in particular a silicate aerogel. Aerogels have very good heat-insulating properties and can be adapted very well to the matrix material and the component material into which the reinforcement unit is inserted through appropriate functionalization.

The invention also relates to a component, i.e. a prefabricated section for the construction of buildings such as houses, in particular a concrete component, comprising a reinforcement unit according to the invention. The component is particularly preferably a component selected from the group consisting of floor, wall and ceiling panels, bridge components such as bridge piers and tunnel tubes. Bridge components are particularly preferred because a strong bending load and thus also tensile forces act on the concrete. Bridge components are also particularly relevant because the very good dynamic properties of the reinforcement unit and the corrosion resistance are particularly effective here.

The reinforcement unit is preferably contained in the component in the form of a grid. The grid-shaped reinforcement unit is particularly preferably arranged in the component in such a way that the grid runs at least partially, preferably completely, parallel to at least one of the surfaces of the component. This results in particularly pronounced reinforcement. In another preferred embodiment, the reinforcement unit according to the invention is a transverse force reinforcement and is thus arranged perpendicular to at least one of the surfaces.

The invention also relates to the use of a reinforcement unit according to the invention for increasing the stability of a component, such as a concrete component, in particular an external concrete component.

• ▪ ein Fasermaterial in Form von Endlosfasern, und
• ▪ ein Matrixmaterial,

umfassen, wobei das Fasermaterial zumindest teilweise, vorzugsweise vollständig, in das Matrixmaterial eingebettet ist, und wobei das Matrixmaterial ein thermoplastisches Polymer umfasst,

• ▪ miteinander stoffschlüssig verbunden werden.

The invention also relates to a method for producing a reinforcement unit according to the invention, wherein two or more reinforcement elements, each having a

• ▪ a fibre material in the form of continuous fibres, and
• ▪ a matrix material,

wherein the fiber material is at least partially, preferably completely, embedded in the matrix material, and wherein the matrix material comprises a thermoplastic polymer,

• ▪ be bonded together in a material-locking manner.

• i) zumindest teilweises Aufschmelzen des thermoplastischen Polymers eines oder mehrerer Bewehrungselemente,
• ii) anschließendes Inkontaktbringen der Bewehrungselemente, sodass aufgeschmolzenes thermoplastisches Polymer eines Bewehrungselementes mit einem zweiten Bewehrungselement in Kontakt tritt und
• iii) anschließendes Abkühlen, sodass eine stoffschlüssige Verbindung entsteht.

The connection is preferably made by

• i) at least partially melting the thermoplastic polymer of one or more reinforcement elements,
• ii) subsequently bringing the reinforcement elements into contact so that molten thermoplastic polymer of one reinforcement element comes into contact with a second reinforcement element and
• iii) subsequent cooling to form a bonded joint.

The two or more reinforcement elements can be produced in an upstream process step by impregnating a fiber material, for example in a pultrusion process.

The invention also relates to a reinforcement unit obtained by the above method.

EXAMPLES

The invention will now be described in more detail using an embodiment and figures.

DESCRIPTION OF AN EMBODIMENT

The reinforcement unit according to the invention can be obtained by thermally joining, in particular ultrasonic welding, several reinforcement elements. The reinforcement elements can be produced by a pultrusion process. The production is explained below by way of example.

The rods or rebars can be manufactured using a pultrusion process, for example, in which one or more dry rovings are first spread and then pulled through an impregnation tool. Plastic melt is fed into the tool via an extruder and the fiber material is impregnated with the polymer. After leaving the impregnation tool, the final shaping, cooling of the pultrudates and assembly take place.

The set tool temperature depends on the thermoplastic polymer used and is typically above the melting temperature (semi-crystalline) or the processing temperature (amorphous) according to the manufacturer's data sheet. The process pressures result from factors such as the tool geometry, the viscosity of the matrix material during processing and the process speed used.

1. A) Abspulen
   • • Ein Carbonfaserstrang (Roving) mit einer Einzelfilamentzahl von 50 k wird von einer Vorratsspule abgespult. Falls erforderlich, werden mehrere Faserstränge zu einem Faserbündel zusammengeführt.
2. B) 1. Imprägnierungsschritt
   • • Durchführung des Rovings oder Faserbündels ohne Vorspannung durch einen Matrixvorläuferbehälter, welcher mit einer Caprolactam-Lösung mit vorbestimmter Viskosität zur Herstellung von Polyamid 6 gefüllt ist. Dabei kann die Lösung erwärmt sein und/oder auch unter Druck stehen. Dies unterstützt den Imprägnierungsvorgang, so dass die relativ flüssige Matrixvorläuferlösung alle Einzelfilamente der Faserstränge vollständig umschließt. Die Zwischenräume der einzelnen Faserstränge werden durch diesen Vorgang mit flüssiger Lösung also ausgefüllt. Die Viskosität der Lösung ist so gewählt, dass ein Eindringen in die Zwischenräume der Faserstränge mit hoher Geschwindigkeit möglich ist.
3. C) 2. Imprägnierungsschritt
   • • Der aus dem Matrixbehälter austretende Faserstrang wird mittels einer Transporteinrichtung weiterbefördert. Die Transporteinrichtung kann eine Heizung besitzen, mittels der der Faserstrang von warmer Luft umströmt wird, um den Gelierprozess der Lösung zu unterstützen, wodurch eine Gelbildung und somit der Härtevorgang initiiert wird.
   • • Der Faserstrang tritt danach in einen zweiten Matrixvorläuferbehälter ein, welcher eine Caprolactam-Lösung höherer Viskosität aufweist. Hier entsteht eine den Faserstrang umhüllende Schicht. Diese Lösung besitzt eine gelartige Konsistenz, wobei die Lösung gegebenenfalls auch erwärmt ist und unter Druck steht. Diese Verfahrensstrecke mit definierter Vorspannung bewirkt, dass die einzelnen Filamente des Faserstrangs aneinanderkleben und die entstandene Mantelfläche den Faserstrang als Ganzes umhüllt.
4. D) Konsolidierung
   • • Der imprägnierte Faserstrang wird in einem Trocknungs- und Aushärtebehälter mittels Wärmestrahlung und unter Einwirkung von Konsolidierungsrollen ausgehärtet.
5. E) Konfektionierung
   • • Der ausgehärtete und abgekühlte Faserstrang wird in einer Schnitteinrichtung auf die gewünschte Dimension zugeschnitten, sodass ein längliches Bewehrungselement erhalten wird.
6. F) Herstellung Bewehrungseinheit
   • • Eine gitterförmige Bewehrungseinheit wird durch das Zusammenfügen mehrerer länglicher Bewehrungselemente erhalten. Die Bewehrungselemente werden an ihren Überkreuzungspunkten kurz erwärmt, miteinander in Kontakt gebracht, abgekühlt und hierdurch über das Matrixmaterial miteinander verbunden.

The pultrusion process preferably comprises the following exemplary sub-steps:

1. A) Unwinding
   • • A carbon fiber strand (roving) with a single filament count of 50 k is unwound from a supply spool. If necessary, several fiber strands are combined to form a fiber bundle.
2. B) 1st impregnation step
   • • The roving or fiber bundle is passed without pre-tension through a matrix precursor container which is filled with a caprolactam solution with a predetermined viscosity for the production of polyamide 6. The solution can be heated and/or under pressure. This supports the impregnation process so that the relatively liquid matrix precursor solution completely encloses all the individual filaments of the fiber strands. The spaces between the individual fiber strands are therefore filled with liquid solution through this process. The viscosity of the solution is chosen so that it can penetrate into the spaces between the fiber strands at high speed.
3. C) 2nd impregnation step
   • • The fiber strand emerging from the matrix container is transported further by means of a transport device. The transport device can have a heater by means of which warm air flows around the fiber strand in order to support the gelling process of the solution, which initiates gel formation and thus the hardening process.
   • • The fiber strand then enters a second matrix precursor container, which contains a caprolactam solution of higher viscosity. This creates a layer that envelops the fiber strand. This solution has a gel-like consistency and may also be heated and under pressure. This process section with defined pre-tensioning causes the individual filaments of the fiber strand to stick together and the resulting surface area envelops the fiber strand as a whole.
4. D) Consolidation
   • • The impregnated fiber strand is cured in a drying and curing tank by means of heat radiation and under the influence of consolidation rollers.
5. E) Packaging
   • • The hardened and cooled fiber strand is cut to the desired dimension in a cutting device so that an elongated reinforcement element is obtained.
6. F) Manufacturing reinforcement unit
   • • A lattice-shaped reinforcement unit is obtained by joining several elongated reinforcement elements. The reinforcement elements are briefly heated at their crossing points, brought into contact with each other, cooled and thereby connected to each other via the matrix material.

FIGURE LIST

The present invention is explained in more detail below with reference to the embodiments shown in the figures.

Short description:

• 1 shows schematically a grid-shaped reinforcement unit according to the invention made of reinforcement elements in the form of rods.
• 2 shows schematically a lattice-shaped reinforcement unit according to the invention made of reinforcement elements in the form of rebars.
• 3 shows schematically a cross-section of a rod (left) and a rebar (right), which represent the reinforcement elements of the 1 and 2 form the reinforcement units shown.

Detailed description:

1 shows schematically a structure of a reinforcement unit 1 according to the invention, which is designed in the form of a grid. The grid consists of a first row of rods 2a arranged parallel to one another and a second row of rods 2b arranged parallel to one another. The two rows cross each other so that crossing points 3 are formed. The crossing rods have been firmly bonded to one another by melting and subsequent cooling.

2 shows schematically a structure of a reinforcement unit 1 according to the invention, which is designed in the form of a grid. The grid consists of a first row of rebars 4a arranged parallel to one another and a second row of rebars 4b arranged parallel to one another. The two rows cross each other so that crossing points 3 are formed. The crossing rebars have been firmly bonded to one another by melting and subsequent cooling.

3 shows schematically a cross-section of a rod (left) and a rebar (right), which represent the reinforcement elements of the 1 and 2 shown reinforcement units. The rod shown on the left side of the figure comprises several tens of thousands of individual filaments of a fiber material, wherein the filaments are uniformly embedded in a thermoplastic matrix (matrix not explicitly shown). The diameter d ₁ of a rod is in the range from 1.5 to 4 mm. The rebar shown on the right side of the figure comprises three rovings, each with several tens of thousands of individual filaments of a fiber material, wherein the filaments are uniformly embedded in a thermoplastic matrix (matrix not explicitly shown). The diameter of the rebar d ₂ is in the range from 4 to 15 mm.

reference sign

1

reinforcement unit

2a, b

Reinforcement elements in the form of rods

3

intersection points

4a, b

Reinforcing elements in the form of rebars

5

Set of single filaments surrounded by matrix (not shown)

QUOTES INCLUDED IN THE DESCRIPTION

This list of 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 accepts no liability for any errors or omissions.

Cited patent literature

• EP 0227207 B1 [0003, 0004]

Cited non-patent literature

• Willems, Fabian, et al. “Determination of the fiber orientation of long glass fiber reinforced thermoplastics using image-optical analysis and computer tomography” German Society for Non-Destructive Testing eV, Ed (2018 [0013]

Claims (16)

Reinforcement unit, in particular for use in a concrete component, which comprises the following components: ▪ a fiber material in the form of continuous fibers, ▪ a matrix material, wherein the fiber material is at least partially, preferably completely, embedded in the matrix material, characterized in that the matrix material comprises a thermoplastic polymer. reinforcement unit according to claim 1 , wherein the thermoplastic polymer is selected from the group consisting of polyamides (PA), in particular PA6, PA 6.6, PA 4.6, polyphthalamides (PPA), polycarbonate (PC), polyvinyl butyral (PVB), polypropylene (PP), polyethylene (PE), polyesters such as polybutylene terephthalate (PBT), polyethylene terephthalate (PET), polyphenylene sulfide, acrylonitrile butadiene styrene (ABS), polyacrylate, polymethacrylate, polyoxymethylene (POM), polycarbonate (PC), polyether sulfone, polyether ketones such as polyether ether ketone (PEEK) or polyether ketone ketone (PEKK), polyphenyl ether (PEI), polyvinyl chloride (PVC), polylactide, polyurethane, ethylene-vinyl acetate copolymer (EVA), polystyrene (PS), copolymers and/or mixtures of the aforementioned polymers, particularly preferably polyamides. Reinforcing unit according to one of the preceding claims, wherein the thermoplastic polymer is semi-crystalline. Reinforcement unit according to one of the preceding claims, wherein the continuous fibers are at least partially, preferably completely, in the form of one or more textile structures, e.g. a fabric. Reinforcement unit according to one of the preceding claims, wherein the continuous fibers are at least partially, preferably completely, in the form of one or more rovings. reinforcement unit according to claim 5 , wherein the number of individual filaments of the one or more rovings is ≥ 40,000, preferably ≥ 50,000. Reinforcement unit according to one of the preceding claims, wherein the fiber material is selected from the group consisting of glass fibers, carbon fibers, basalt fibers, ceramic fibers, steel fibers, polymer fibers such as synthetic fibers, in particular aramid and nylon fibers, or natural polymer fibers such as flax, hemp or protein fibers, preferably selected from carbon and glass fibers. Reinforcement unit according to one of the preceding claims, wherein the reinforcement unit comprises a plurality of elongate reinforcement elements which comprise the fiber and the matrix material and which are connected to one another at at least one connection point, preferably at least one crossing point. reinforcement unit according to claim 8 , wherein the reinforcement unit is designed in the form of a grid. reinforcement unit according to claims 8 or 9 , wherein the elongated reinforcement elements are materially connected to one another at at least one connection point. reinforcement unit according to claim 10 , wherein the elongate reinforcement elements are integrally connected to one another at the at least one connection point by plastic welding, preferably ultrasonic welding. Reinforcement unit according to one of the preceding claims, wherein the reinforcement unit comprises a coating which preferably comprises a flame retardant. reinforcement unit according to claim 12 , wherein the coating comprises an aerogel, in particular a silicate aerogel. System for producing a reinforcement unit according to one of the preceding claims, comprising a plurality of, preferably elongated reinforcement elements, comprising ▪ a fiber material in the form of continuous fibers, ▪ a matrix material, wherein the fiber material is at least partially, preferably completely, embedded in the matrix material, wherein the matrix material comprises a thermoplastic polymer. Component, in particular concrete component, comprising a reinforcement unit according to one of the preceding claims. Use of a reinforcement unit according to one of the Claims 1 - 13 to increase the stability of a component, in particular a concrete component, such as an external concrete component.

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