ES3015584B2 - Procedure for obtaining a unidirectional polymeric tape and unidirectional polymeric tape obtained by said procedure - Google Patents

Description

DESCRIPTION

PROCEDURE FOR OBTAINING A UNIDIRECTIONAL POLYMERIC TAPE AND

UNIDIRECTIONAL POLYMERIC TAPE OBTAINED BY SAID PROCEDURE

OBJECT OF THE INVENTION

The present invention relates to a process for obtaining a unidirectional (i.e., flat, two-dimensional) polymeric sliver from a three-dimensional precursor carding roving composed of recycled reinforcing fibers, preferably short carbon fibers, which are staple fibers. The unidirectional polymeric sliver obtained by this process is also an object of the invention.

Advantageously, by means of the procedure of the present invention it is possible to obtain unidirectional polymer tapes with application in composites based on recycled reinforcing fibers, an aspect that is currently only obtained using virgin continuous fibers.

BACKGROUND OF THE INVENTION

Unidirectional reinforcing fiber tapes (mainly carbon) are known in the state of the art, obtained from virgin reinforcing fibers, in whose obtaining procedures start from continuous filaments.

Short carbon fibers, whether recycled (rCF, acronym for recycled carbon fibers) or virgin, are an excellent reinforcement material; however, it is not possible to orient them by continuous methods, such as those used in the production of conventional unidirectional tapes.

Currently, these short carbon fibers can only be processed to obtain webs or non-woven fabrics, which serve as intermediates in textile processes. However, the textiles or composites obtained from these webs offer inferior mechanical properties to those obtained from continuous filaments, due to the random and non-directional distribution of the fibers in these webs or non-woven fabrics obtained from staple fibers. In this regard, the only known method to date that allows the processing of carbon staple fibers with textile techniques is that disclosed in patent application P202330884, from the same applicant as the present invention. This method allows the production of textile intermediates (tapes) with a high degree of directionality, which can be used as precursors to the present invention.

It is worth noting that prior art methods exist for obtaining unidirectional tapes, such as the one disclosed in the article by Detzel, M.; Mitschang, P.; Breuer, U., "New Approach for Processing Recycled Carbon Staple Fiber Yarns into Unidirectionally Reinforced Recycled Carbon Staple Fiber Tape," published in Polymers 2023, 15, 4575. This article describes a process in which recycled carbon staple fiber (rCF) yarns and polyamide (PA6) are transformed into tape. In this process, the starting material containing rCF is in yarn form. Therefore, the process disclosed in this document does not allow for the direct processing of a mixture of short carbon fibers and polymer fibers to obtain a precursor carding roving. Instead, an additional spinning process is required to obtain rCF yarn.

On the other hand, the document Khurshid MF, Hasan MMB, Abdkader A, Cherif C. 'Processing of waste carbon and polyamide fibers for high performance thermoplastic composites: A novel manufacturing technology for unidirectional tapes structure'. Journal of Industrial Textiles.

2022;51(4_suppl):7256S-7276S discloses a process for obtaining a tape from polyamide (PA6) and rCF fibers in different proportions. These fibers are opened and passed through a carding machine to form a tape, which then passes through a drawing frame for homogenization. Subsequently, a plurality of these tapes are arranged in parallel and compacted and overlapped by rollers before being thermocompressed to form a single tape. Thus, in the process disclosed in this document, it is necessary to use several starting tapes to obtain a final tape with an ideal weight and thickness for its subsequent application. This results in the final tape not offering the desired homogeneity, since irregularities in weight, thickness, and width can occur depending on how the tapes are stacked or inserted.

Finally, in the document Alexandre Faure, Olivier Mantaux, and Arnaud Gillet, Univ. Bordeaux, ‘Performances of composites made from different recycled carbon fiber semi-products’ I2M, CNRS, UMR 5295, F-33400 Talence, France, a process for obtaining a tape comprising carbon fibers is disclosed. In this process, the tapes are manufactured from unidirectionally aligned carbon fibers, thermoplastic powder binders are applied to them, and the assembly is subsequently consolidated with hot air. Therefore, in this case, the precursor that enables the tape consolidation by heat is applied during the process in powder form, making it more complex to control uniformity and dosage through powder addition. On the other hand, as detailed later, the heated cylinders provided in the equipment and process of the invention generate a greater degree of consolidation than a hot air oven.

The cited background shows pilot-scale processes and/or processes with numerous manual stages, which limits their potential for automation and the possibility of working continuously.

Thus, the applicant of the present invention detects the need to develop a procedure and, consequently, a product, that enables the direction of short carbon fibers based on application P202330884 and subsequently the melting, cutting and handling of this unidirectional tape so that the fibers are parallelized, aligned and consolidated on the polymer matrix, improving the mechanical properties of current solutions (veils or non-woven fabrics), operating continuously and in an automated manner.

DESCRIPTION OF THE INVENTION

The proposed procedure enables the production of unidirectional (two-dimensional) thermoplastic slivers made with virgin or recycled carbon fibers combined with polymer fibers, preferably thermoplastic and/or inorganic fibers. This is achieved using three-dimensional precursors (precursor card roving) obtained through the textile treatment process for carbon and other fibers disclosed in application P202330884. To this end, a process has been designed using the precursor card roving, based on thermal consolidation, cutting, and winding techniques to produce a hybrid card sliver. The parameters and technical modifications employed in the proposed procedure are key, as detailed below.

In this sense, the invention is defined according to the set of claims that accompany this document.

Advantageously, employing a fiber carding process that parallelizes and aligns the fibers from a mixture containing chopped carbon fibers allows for the transformation from an anisotropic material (webs or non-woven fabrics) to an isotropic material in a unidirectional format (unidirectional tape). This improves upon current market solutions (webs or non-woven fabrics) by offering an isotropic tape material with variable width and partially oriented fibers.

Specifically, the novelty of the invention lies in the use of chopped carbon fiber, preferably from recycled carbon fibers (rCF), since no processes are known for obtaining unidirectional (i.e., flat or two-dimensional) hybrid tapes of polymeric and/or inorganic fibers combined with chopped carbon fibers. The chopped carbon fibers have a length between 20 mm and 120 mm, preferably between 30 mm and 80 mm.

The procedure of the invention can be carried out in equipment that has a cylinder carding zone, a feed zone to a part of the equipment where the obtaining of the unidirectional polymeric tape takes place, i.e., the so-called unidirectional polymeric tape obtaining zone.

The cylinder carding area is provided with at least the following elements:

- a pair of feed rollers, also known as feed cylinders,

- a taking cylinder, also known as a takerinolicker-in,

- a pair of worker-cleaners, also known as stripperworkers

- a central cylinder or boot, usually called in English main cylinder or Swift, - an extractor cylinder or doffer,

- a conveyor belt,

- a drawing box area where a hybrid card sliver is formed, and - a sliver winder or coiler for winding the hybrid card sliver, which is the precursor to the unidirectional polymer sliver that is the subject of the invention. The winder collects the precursor card sliver or roving for subsequent processing in the equipment that is the subject of the invention. Optionally, the equipment includes an accessory known as a twister for applying twist if necessary.

Preferably, the roller carding machine has two pairs of feed rollers, a take-up roller, three pairs of worker-cleaner rollers, a central roller, an extractor roller, a drafting zone and a tape winder or coiler.

Thus, the feed cylinders, the worker cylinders, the cleaning cylinders, the central cylinder and the extractor cylinder are provided with a pinned lining.

The procedure for obtaining the three-dimensional precursor carding sliver that serves as raw material comprises the following stages:

- Handling of at least 10% chopped carbon fibers (virgin or recycled) with a length between 20 mm and 120 mm, and a maximum of 90% polymeric and/or inorganic fibers using fiber opening and blending technology. The chopped carbon fibers may come from a recycling process, such as pyrolysis or solvolysis applied to a composite. Optionally, during this first handling stage, a desizing binder (compatibiliser) and/or a binding agent is added, individually or in combination, before and/or after blending the fibers, in a percentage of less than 5% of the total weight of the fiber blend. Desizing additives can be organosilanes or matrix/reinforcement compatibilizing additives, while sizing agents - compounds of a fatty nature that are added to facilitate the mechanical processing of fibers and protect fragile fibers such as rCF from breakage - can be antistatic additives, fiber cohesion-enhancing additives or lubricating additives, among others;

- feeding the mixture of chopped carbon fibers and open polymer and/or inorganic fibers to a machine with a roller card and a feeding zone to a zone for obtaining the unidirectional polymer sliver. Thus, the roller card consists of a rigid or semi-rigid lining (metal teeth), using different combinations of angles and tooth density optimized according to the mixture and length of fibers;

- carding (aligning and cohesiveening of fibers) of the fiber mixture and obtaining a hybrid carded sliver of uniform thickness with a count between 2.0 and 8.0 kTex and a twist between 0 v/m and 50 v/m;

- folding and fineening of at least one hybrid carded sliver using a draw-frame - also known as a drafter or draw-frame, applying draft ratios between x1 and x10, obtaining a draw-frame sliver;

- folding and twisting of at least one roving sliver using a roving-twisting machine - also known as a roving frame - obtaining a precursor carding roving with a count between 0.4 and 3.0 kTex and a false twist between 5 v/m and 50 v/m (indifferently in the S or Z direction);

Preferably, the polymer fibers are also water-soluble. Advantageously, this allows them to be removed in subsequent complementary processes of solubilizing these already embedded fibers, leaving a final unidirectional polymer tape with the highest possible percentage of carbon fiber, since the latter does not dissolve.

The use of polymeric fibers, whether thermoplastic, thermoset, or of a similar nature, contributes to the proper processing for obtaining a precursor carding sliver using the textile technologies described above. These polymeric fibers act as a "matrix" element in the various final composite manufacturing processes in which the unidirectional polymeric sliver of the invention may participate. This sliver may be thermoplastic or thermoset, depending on the nature of the polymeric fibers employed. Examples of thermoplastic fibers include polyamide, polypropylene, or polyester; high-performance fibers such as PPS, PEEK, PAEK, etc.; natural fibers; or water-soluble fibers such as PVA. Thermoset fibers could include aramids, ultra-high-molecular-weight polyethylene (UHMWPE), or similar materials.

Thus, the unidirectional polymer tape of the invention is particularly advantageous for fabric manufacturing and subsequent thermocompression, infusion, RTM (Resin Transfer Moulding), lay-up, or similar composite manufacturing processes to produce a desired preform or product. In the case of thermoplastic composites, the fibers are fused into the matrix after selecting the correct ratio of chopped, recycled, or virgin carbon fibers and thermoplastic (TP) fibers. In the case of thermoset composites, the thermoplastic fibers may or may not be compatible with the thermoset resin used, dissolving during the infusion-curing process or becoming embedded between the matrix and the reinforcement.

It should be noted that the equipment where the procedure of the present invention can take place, in addition to the described cylinder carding machine that allows obtaining the precursor carding sliver or roving, comprises a zone for obtaining the unidirectional polymeric sliver, which has at least a preheating zone, a melting and consolidating zone, a zone for cutting the required sliver width and a winding station.

Thus, the area for obtaining the unidirectional polymeric sliver is provided with at least the following elements for treating the precursor carding sliver or roving:

- an unwinding zone for precursor carding slivers or rovings, comprising a feeding zone for precursor carding slivers obtained in the previous carding zone, and a positioning or alignment system for the precursor carding slivers. Thus, in this unwinding zone, one or more precursor carding slivers are placed and centered for their aligned and torsion-free insertion into the subsequent elements of the equipment;

- a pair of feed cylinders with adjustable pressure;

- a preheating oven, preferably using IR (infrared) lamps; - a pair of heated compaction cylinders with adjustable pressure;

- a cooling zone, preferably assisted by forced aeration;

- a pair of cylinders equipped with two blades with the possibility of varying the cutting width;

- a pair of drag cylinders for the consolidated and cut tape;

- a winding voltage compensator;

- a reel winding station; and

- A motorized and synchronized drive system for all mechanical elements with variable speed controlled by a controller. Advantageously, the controller allows 1:1 synchronization between all mechanical elements in the unidirectional polymer tape production area, a synchronization that remains constant for continuous operation.

This equipment configuration is not limiting to the invention, since equipment could be given with different configurations of preheating zone, consolidation zone (heated cylinders with adjustable pressure), consolidated material drag cylinders, and cutting cylinders/blades.

According to the essence of the invention, the procedure for obtaining a continuous unidirectional polymeric tape from the precursor carding sliver obtained in the series of steps described above comprises the following steps:

- Placement and centering of (one or more) precursor carding strands in the feeding area to the unidirectional polymer sliver production area, for their introduction in an aligned manner and without twisting into it,

- feeding the precursor carding sliver to the pair of feeding cylinders, so that these apply sufficient pressure to draw the material to the preheating zone, preferably between 0.2 and 2.0 bar;

- passing the precursor carding sliver through a preheating oven (preferably composed of IR lamps) at a temperature between 5-70% lower than its melting temperature (preferably between 15-40%), obtaining a preheated sliver;

- Passage of the preheated tape through a pair of cylinders heated to a temperature close to, but below, its melting point, between 5-70% lower (preferably between 5-30%) for tape consolidation,

- passage of the consolidated belt through a cooling zone, preferably by forced ventilation,

- The consolidated and cooled tape passes through two cylinders equipped with blades, the width and distance between which can be modified, to obtain unidirectional polymer tapes with a width between 2 and 80 mm, preferably between 10 and 40 mm, and a thickness preferably between 0.1 and 3.0 mm. The width and distance between the blades can be modified using a machined cylinder with different widths for positioning the blades.

- The consolidated and cut unidirectional polymer tape, cut to the desired width, passes through a tension compensator connected to the winding system, allowing adjustment of the winding tension. The tension compensator preferably consists of a rocker arm and a counterweight, and operates with a preferred pressure between 0.1 and 10 N/m. Advantageously, the motorized and synchronized traction system included in the equipment allows the winding process to be adjusted by the controller, so that the winding speed is proportional to the speed of the other mechanical elements of the equipment that produce the unidirectional tape of the invention; and

- winding of the unidirectional polymer tape cut into reels of fixed or variable width according to the length of the tape obtained, so that by means of the motorized and synchronized traction system the winding process is adjusted, the winding speed being proportional to the speed of the rest of the cylinders and mechanical elements of the equipment that allow obtaining the unidirectional tape.

Thus, by means of the described procedure it is possible to obtain a two-dimensional unidirectional polymeric tape, starting from a precursor three-dimensional carding sliver obtained from short-length carbon fibers.

It should be noted that the resulting unidirectional polymer tape has a width between 2 and 80 mm. According to one preferred embodiment, it ranges from 2 to 8 mm, while in another embodiment, the tape width is preferably between 10 and 40 mm. Optionally, this unidirectional polymer tape has a thickness between 0.1 and 3.0 mm.

BRIEF DESCRIPTION OF THE DRAWINGS

To complete the description that follows and to aid in a better understanding of the characteristics of the invention, a set of drawings is included as an integral part of said description, in which, for illustrative and non-limiting purposes, the following has been represented:

Figure 1 shows a schematic side view of equipment for obtaining the carding sliver precursor of the unidirectional polymeric tape according to the object of the invention.

Figure 2 shows a perspective view of a detail of the equipment in the previous figure.

Figure 3 shows a schematic of the details of the pin trim used in the carding cylinders of the equipment in Figures 1 and 2 and the parameters that define them.

Figure 4 shows a schematic of the details of the equipment area in which the production of the unidirectional polymer tape is carried out according to a preferred embodiment of the invention.

PREFERRED EMBODIMENT OF THE INVENTION

To carry out the procedure of the invention illustrated in Figure 4, equipment comprising at least the following elements may be used:

- a feeding zone (19) of precursor carding strands (29);

- a positioning system - alignment (20) of the carding strands (29);

- a pair of adjustable pressure feed cylinders (21);

- a preheating oven (22);

- a pair of heated compaction cylinders with adjustable pressure (23);

- a cooling zone (24);

- a pair of cutting cylinders with two variable width blades (25);

- a pair of cutting tape feed cylinders (26);

- a winding voltage compensator (27); and

- a reel winding station (28)

Figure 1 shows a schematic side view of the equipment used to obtain the precursor carding sliver, which serves as the starting material for producing the unidirectional polymer sliver of the invention. This equipment comprises a pair of feed rollers (1), a take-up roller (2), three pairs of worker rollers (3) and cleaner rollers (4), a central roller (5), an extractor roller (6), a comber (7), a conveyor belt (8), a drafting zone (9), and a sliver winder (10) or coiler.

On the other hand, Figure 2 illustrates a detail of an analogous piece of equipment for obtaining the precursor carding sliver with the same number and type of cylinders in the carding machine, but where the conveyor belt (8) is incorporated, which is arranged between the extraction cylinder zone (6) and the drawing zone (9) (draw box zone).

As detailed above, the conveyor belt (8) is synchronized with the carding machine speeds by means of gears that maintain the traction ratios of the cylinders. This advantageously ensures belt cohesion and prevents breakage. Specifically, the working cylinders (3) maintain a fixed traction ratio with the extractor cylinder (6) and the conveyor belt (8) (assembly A), the cleaning cylinders (4) maintain a fixed traction ratio with the central cylinder (5) (assembly B), and the feeding cylinders (1) (assembly C) have variable speed. Thus, thanks to a control system, the speeds of assemblies A, B, and C can be modified independently from the machine, but each assembly of elements has a fixed traction ratio (through a gear configuration, which cannot be changed). Advantageously, the independent variation of the speeds of sets A, B and C allows, on the one hand, a stable production process by allowing the adjustment of asynchronies, and, on the other hand, varying the output weight with respect to the input material, as well as increasing or decreasing the degree of carding of the fibers at will, depending on the desired final product.

In the embodiment illustrated in Figure 2, triangular plates (15) with air blowers (16) are arranged on the conveyor belt (8). These plates (15) act as deflector partitions to help the fiber web converge into a ribbon, ensuring its cohesion. This ribbon is then collected by a collector (18). Alternatively, the plates (15) could form part of the base of the conveyor belt (8).

Figure 3 schematically details the different parameters of the spikes (11).

The parameter combinations for the barbed slivers will be determined for each specific fiber blend to ensure the correct formation of a web, which will initially form the carded roving precursor to the final unidirectional polymer sliver. According to a preferred embodiment, the barbed sliver (11) will be configured as follows:

- in the feed cylinders (1) the prongs (11) have a base (12) with a width between 1 mm and 5 mm and a height (13) between 5 and 8 mm, so that the prongs (11) are arranged with a front angle (17) between 50° and 80°, a pitch (14) between prongs (11) between 3.6 mm and 9 mm, and a density between 15 and 100 prongs;

- in the cleaning cylinders (4) the tines (11) have a base (12) with a width between 1.1 mm and 3.2 mm and a height (13) between 4 and 5 mm, so that the tines (11) are arranged with a front angle (17) between 50° and 80°, a pitch (14) between tines (11) between 3.6 mm and 9 mm, and a density between 24 and 170 tines per inch;

- in the working cylinders (3) the prongs (11) have a base (12) with a width between 1.3 mm and 4.25 mm and a height (13) between 5 and 7.5 mm, so that the prongs (11) are arranged with a front angle (17) between 50° and 65°, a pitch (14) between prongs (11) between 4 mm and 8.5 mm, and a density between 80 and 160 prongs per inch;

- in the central cylinder (5) the prongs (11) have a base (12) with a width between 0.9 mm and 3.2 mm and a height (13) between 3.5 and 5 mm, such that the prongs (11) are arranged with a front angle (17) between 50° and 80°, a pitch (14) between prongs (11) between 2.5 mm and 8.5 mm, and a density between 24 and 224 prongs per inch; and

- in the extractor cylinder (6) the prongs (11) have a base (12) with a width between 1.4 mm and 4.25 mm and a height (13) between 3.5 and 5 mm, so that the prongs (11) are arranged with a front angle (17) between 50° and 60°, a pitch (14) between prongs (11) between 4 mm and 8.5 mm, and a density between 18 and 160 prongs per inch.

Thus, according to a preferred embodiment, to obtain the precursor carding sliver, starting from a mixture of fibers with at least 10% of carbon fibers cut to a length between 20 mm and 120 mm and a maximum of 90% of thermoplastic polymer fibers, the following procedure is followed:

- Manipulation of at least 10% of cut carbon fibers with a length between 20 mm and 120 mm, and a maximum of 90% of thermoplastic polymer fibers by fiber opening and mixing technology, resulting in a fiber mixture in the form of an uncarded veil;

- feeding the mixture of chopped carbon fibers and open thermoplastic polymer fibers to the cylinder carding equipment;

- carding of the fiber mixture and obtaining a hybrid card sliver of uniform thickness with a count between 2.0 and 8.0 kTex and a twist between 0 v/m and 50 v/m;

- folding and fineening of at least one hybrid card sliver using a draw frame applying draft ratios between x1 and x10, obtaining a draw frame sliver; - folding and twisting of at least one draw frame sliver using a roving twisting machine obtaining a precursor card roving with a count between 0.4 and 3.0 kTex and a false twist between 5 v/m and 50 v/m;

Once the precursor carding wick (29) has been obtained, in accordance with the object of the present invention, the following steps are carried out:

- Placement and centering of one or more precursor carding strands (29) in the feeding area (19) for their introduction in an aligned and twist-free manner into the machine;

- feeding of the precursor carding slivers (29) to the pair of feeding cylinders (21), which apply sufficient pressure (between 0.2 and 2 bar) to draw the material to the preheating zone,

- passing the precursor carding strands (29) through the preheating oven (22) (preferably composed of IR lamps) at a temperature between 5-70% lower than their melting temperature (preferably between 15-40%);

- passage of the preheated tape through a pair of heated compaction cylinders (23) at a temperature close to its melting point between 5-70% (preferably between 5-30%), the pressure applied by this pair of heated cylinders being adjustable by the controller, preferably between 0.2 and 2 bar;

- passage of the consolidated belt through a cooling zone (24), preferably by forced ventilation;

- passing the consolidated tape through two cylinders equipped with blades (25) with the possibility of modifying the width/distance between them, to obtain unidirectional polymeric tapes with a width between 2 - 80 mm, preferably between 10 - 40 mm;

- passage of the consolidated and cut tape to the desired width through a winding tension compensator (27) connected to the winding station (28) winding that allows adjustment of the winding tension, by means of a potentiometer controlled by the controller that applies greater or lesser tension to the consolidated tape depending on the parameters indicated to the controller,

- winding of the cut tape onto reels of fixed or variable width according to the length of the unidirectional tape obtained.

Thus, through a motorized and synchronized traction system, the winding process is adjusted, with the winding speed being proportional to the speed of the rest of the cylinders and mechanical elements of the equipment that allow obtaining the unidirectional polymer tape.

Claims (1)

1a.- Procedure for obtaining a unidirectional polymeric tape characterized in that it comprises the steps of: - Manipulation of at least 10% of cut carbon fibers with a length between 20 mm and 120 mm, and a maximum of 90% of polymeric and/or inorganic fibers by fiber opening and mixing technology; - feeding the mixture of cut carbon fibers and open polymeric and/or inorganic fibers to a machine with a roller card and a feeding zone to a zone for obtaining the unidirectional polymeric sliver; - carding of the fiber mixture and obtaining a hybrid card sliver of uniform thickness with a count between 2.0 and 8.0 kTex and a twist between 0 v/m and 50 v/m; - folding and fineening of at least one hybrid card sliver by means of a draw frame applying draft ratios between x1 and x10, obtaining a draw frame sliver; - folding and twisting of at least one draw frame sliver by means of a roving twisting machine obtaining a precursor card roving (29) with a count between 0.4 and 3.0 kTex and a false twist between 5 v/m and 50 v/m; - placement and centering of at least one precursor carding wick (29) in the feeding zone (19) to the unidirectional polymeric tape production zone, for its introduction in an aligned and twist-free manner into the same; - feeding the precursor carding sliver (29) to a pair of feed cylinders (21) which apply a pressure between 0.2 and 2 bar to draw the material into a preheating zone; - passing the precursor carding sliver through a preheating oven (22) at a temperature between 5-70% lower than its melting temperature, obtaining a preheated sliver; - passing the preheated tape through a pair of heated cylinders (23) at a temperature below its melting point between 5-70%, obtaining a consolidated tape; - passage of the consolidated belt through a cooling zone (24); - passage of the consolidated tape through two cylinders equipped with blades (25) with the possibility of modifying the width/distance between them, to obtain unidirectional polymeric tapes with a width between 2-80 mm; - passage of the unidirectional polymer tape cut to the desired width through a tension compensator (27) connected to a reel winding station (28) that allows adjustment of the winding tension; and - winding of the unidirectional polymer tape cut into reels of fixed or variable width according to the length of the tape obtained; so that by means of a motorized and synchronized traction system the winding process is adjusted, the winding speed being proportional to the speed of the rest of the cylinders and mechanical elements of the equipment that allow obtaining the unidirectional polymer tape. 2a Method of obtaining a unidirectional polymeric tape according to claim 1a characterized in that in the stage of handling cut carbon fibers and polymeric and/or inorganic fibers a desizing additive and/or a sizing agent is added. 3a.- Method for obtaining a unidirectional polymeric tape according to claim 1 a characterized in that the polymeric fibers are thermoplastic fibers or thermoset fibers. 4a.- Procedure for obtaining a unidirectional polymeric tape according to claim 1 a characterized in that the polymeric fibers are water-soluble fibers. 5a.- Procedure for obtaining a unidirectional polymeric tape according to claim 1 a characterized in that the step of passing the precursor carding sliver through the preheating oven (22) is carried out at a temperature between 15-40% lower than its melting temperature. 6a.- Procedure for obtaining a unidirectional polymeric tape according to claim 1a characterized in that the step of passing the preheated tape through the pair of heated cylinders (23) is carried out at a temperature between 5-30% lower than the melting point of the preheated tape. 7a.- Method of obtaining a unidirectional polymer tape according to claim 1a characterized in that the winding tension compensator (27) operates at a pressure between 0.1 and 10 N/M. 8a.- Unidirectional polymeric tape obtained by the procedure of claim 1a characterized in that it has a width between 2 and 8 mm. 9a.- Unidirectional polymeric tape obtained by the procedure of claim ia characterized in that it has a width between 10 and 40 mm. 10a.- Unidirectional polymeric tape obtained by the procedure of claim ia characterized in that it has a thickness between 0.1 and 3.0 mm.