Method for manufacturing a fire-resistant and / or fire-retardant cable

Abstract

The present invention relates to a method for manufacturing a cable comprising at least one elongated electrically conductive element and at least one composite layer surrounding said elongated electrically conductive element, said composite layer being obtained from a roll of non-woven fibrous material impregnated with a geopolymer composition. Figure for the abstract: Fig. 1

Description

Title of the invention: Method for manufacturing a fire-resistant and / or fire-retardant cable

[0001] The present invention relates to a method for manufacturing a cable comprising at least one elongated electrically conductive element and at least one composite layer surrounding said elongated electrically conductive element, said composite layer being obtained by impregnating a non-woven fibrous material with a geopolymer composition.

[0002] It typically applies, but not exclusively, to fire-retardant and / or fire-resistant cables intended for power transmission and / or data transmission, such as fire-retardant and / or fire-resistant electrical and / or optical safety cables, particularly halogen-free ones, capable of operating for a given period of time under fire conditions without propagating the fire or generating significant smoke. These safety cables are, in particular, medium-voltage power transmission cables (especially from 6 to 45-60 kV) or low-frequency transmission cables, such as control or signaling cables.

[0003] From WO 2016 / 099200, a process for manufacturing a fire-resistant cable is known, comprising the following steps: a step of preparing a geopolymer composition comprising sodium silicate, water, potassium hydroxide, an aluminosilicate, and polypropylene fibers; a step of winding a non-woven paper tape around an assembly of copper conductors; a step of impregnating the copper conductor / non-woven paper tape assembly by dipping and coating it in the previously prepared geopolymer composition to form a composite layer surrounding the copper conductors; and then a step of hot extrusion of a polymer protective sheath. The process is lengthy, particularly due to the drying step, and cannot be carried out continuously. Furthermore, the cable components near the geopolymer-based composite layer can be easily contaminated by the geopolymer composition.

[0004] An object of the invention is to overcome all or part of the aforementioned disadvantages, and to provide a method for manufacturing a fire-retardant cable, said method being easy to implement, and in particular easily industrializable, economical and fast, and allowing to lead to a cable having good mechanical properties, in particular in terms of flexibility and durability.

[0005] According to a first aspect, the invention relates to a method for manufacturing a cable comprising at least one elongated electrically conductive element and at least one composite layer surrounding said elongated electrically conductive element, ca characterized in that the composite layer surrounding said elongated electrically conductive element is formed by applying around said cable comprising at least one elongated electrically conductive element a ribbon of fibrous material impregnated with a geopolymer composition,

[0006] where said impregnated tape is delivered from a roll (more commonly referred to as a "roll" or "pancake") prepared (in situ or otherwise) according to the following steps: (i) impregnate a non-woven fibrous material tape with a geopolymer composition, in order to form a tape impregnated with said geopolymer composition, ii) heat-treat the impregnated tape obtained in step i) to form a partially dried, impregnated tape, iii) form the roll by rolling the partially impregnated and dried ribbon from step (ii) onto itself.

[0007] The method of the invention thus comprises a step of applying, around the cable comprising at least one elongated electrically conductive element, the tape which is delivered from the roller. This step of applying the tape from the roller around the cable will be designated hereafter as "step iv".

[0008] According to another aspect, the invention relates to a roll of partially impregnated and dried tape useful in the process of the invention, and which can be obtained according to the aforementioned steps (i) to (iii). This roll comprises a tape of fibrous material impregnated with a heat-treated and partially dried geopolymer composition, said partially impregnated and dried tape being wound around itself about an axis perpendicular to its longitudinal axis.

[0009] Step ii) is a heat treatment that induces progressive solidification by formation ("setting") of a geopolymer from the composition that impregnates the tape. This treatment is carried out in such a way that this solidification is only partial, which allows the impregnated composition to become viscosified and transformed into a paste-like composition that nevertheless retains a certain flexibility in the tape, to allow its unwinding and handling in step iv).

[0010] In this description, for the sake of brevity, the heat treatment step ii) is sometimes referred to as the "drying" step, and similarly, the resulting tape will be described as an impregnated and "partially dried" tape, although step ii) involves more complex processes than simple drying and leads more to geopolymer formation than to water removal. In other words, the notion of "partial drying" of the impregnated tape refers more to a only partial "setting" of the geopolymer composition.

[0011] In practice, to prevent changes in the setting of the geopolymer composition between step (iii) and step (iv), the tape can advantageously be protected in a sealed enclosure between steps (iii) and (iv). The roll of tape impregnated and dried by tiellement according to the invention is typically supplied in a sealed enclosure of this type, for example packaged in a sealed envelope, for example a hermetically sealed plastic bag.

[0012] For the purposes of this description, the term "ribbon" refers to a deformable strip which, when flattened, has substantially the geometry of a flattened and highly elongated parallelepiped, namely with a thickness much less than its width (typically at least by a factor of 10), and a width itself much less than its length (typically at least by a factor of 100). The two opposite faces of the parallelepiped with the largest dimensions are designated as "faces" of the strip, as opposed to the others which constitute its lateral "slices". A ribbon has a longitudinal axis of symmetry, which runs through the ribbon along its entire length and which will be designated herein as the "longitudinal axis" of the ribbon.

[0013] A ribbon said to be "rolled upon itself" here refers to a ribbon which is shaped by rolling around an axis so that one of its faces comes opposite its opposite face (typically inducing direct contact between the two faces: in the context of the invention, according to specific embodiments, a non-stick film can be envisaged between the facing faces, but the use of such a film is generally not desirable), and this with an overlap rate of the two facing surfaces which is typically at least 90%, or even at least 95% and preferably at least 99%.In the useful roll according to the process of the invention, the winding of the ribbon upon itself is carried out around an axis perpendicular to the longitudinal axis of the ribbon, namely by winding the ribbon upon itself in the direction of its length, whereby the resulting roll typically has substantially the shape of a cylinder whose height along the generatrix is ​​substantially equal to the width of the ribbon.

[0014] The winding of the ribbon during step iii) is preferably carried out by placing the opposite faces of the ribbon exactly opposite each other, whereby the roll has in the end the shape of a cylinder whose height along the generatrix is ​​equal to the width of the ribbon, but variations due to inaccuracies in the winding are conceivable, which may lead to a slightly higher height, which preferably remains less than 1.5 times the width of the ribbon.

[0015] The useful roller according to the invention most often takes the form of an assembly comprising a support around which the tape is wound. Where applicable, this support serves as the winding axis for the roller. This support, when present, typically has a length greater than or equal to the width of the tape. It may, in particular, be a rigid part (such as a core or a cylindrical drum) typically having the shape of a cylinder (preferably with a circular cross-section, although other geometries are conceivable in principle), the tape then being wound around the generatrix of this cylinder.

[0016] The process of the invention is rapid, easy to implement, particularly from an industrial standpoint, economical, and it guarantees the production of a fire-resistant and / or fire-retardant cable with good mechanical properties, especially in terms of flexibility and durability. Furthermore, the process of the invention prevents contamination of the cable components near the composite layer by the geopolymer composition.

[0017] The specific use of a roller to deliver the partially dried and impregnated tape makes the process of the invention even easier to implement. This roller can be prepared upstream of step iv), possibly at a site other than that of step iv), and stored for significant periods of time, and it also has the advantage of being able to be transported over long distances if necessary (where applicable, the roller is generally packaged in a sealed envelope).

[0018] The implementation of steps i) and ii) makes it possible to easily and quickly obtain an impregnated and partially dried tape where the quantity of geopolymer deposited is homogeneous and controlled, which in particular allows easy winding of the tape and obtaining a winding of homogeneous geometry.

[0019] Various aspects and possible embodiments of the invention are described in more detail below. The non-woven fibrous material

[0020] The nonwoven fibrous material used according to the invention, particularly in step i) and present in the roll obtained at the end of step iii), preferably has a soft and flexible structure. Furthermore, it is preferable that it have good mechanical properties of tensile and tear resistance.

[0021] This non-woven fibrous material may in particular be chosen from cellulosic materials, materials based on synthetic organic polymers, glass fibers, and one of their mixtures, and preferably from materials based on synthetic organic polymers.

[0022] Cellulosic materials can be selected from paper, in particular blotting paper; non-woven materials made from functionalized or non-functionalized cellulose; matrices with an alveolar and / or fibrous structure made from natural cellulose acetate fibers.

[0023] Synthetic organic polymer-based materials can be selected from porous and / or fibrous matrix polymer materials of polyolefin(s), in particular those selected from propylene homo- and copolymers, ethylene homo- and copolymers, high-density polyethylenes (HDPE), aromatic polyamides (aramids), polyesters, and mixtures thereof.

[0024] According to a preferred embodiment of the invention, the non-woven fibrous material is polyethylene terephthalate (PET).

[0025] The non-woven fibrous material preferably has a basis weight of approximately 50 to 120 g / cm². This makes it possible to obtain a composite layer that is sufficiently flexible for easy handling and sufficiently robust to ensure mechanical properties compatible with the impregnation and drying process and, in combination with the impregnated geopolymer composition, to obtain good fire protection.

[0026] According to a preferred embodiment of the invention, the non-woven fibrous material represents from 2 to 95% by weight approximately, particularly preferably from 5 to 45% by weight approximately, and even more preferably from 10 to 35% by weight approximately, relative to the total weight of the composite layer. The geopolymer composition

[0027] The geopolymer composition used in step i) is preferably a liquid geopolymer composition.

[0028] The geopolymer composition used in step ii) is preferably an aluminosilicate geopolymer composition.

[0029] The geopolymer composition of the invention is particularly preferably a geopolymer composition comprising water, silicon (Si), aluminum (Al), oxygen (O), and at least one element selected from potassium (K), sodium (Na), lithium (Li), cesium (Cs), and calcium (Ca), and preferably selected from potassium (K) and sodium (Na).

[0030] The geopolymer composition may in particular comprise at least a first aluminosilicate, at least a first alkali silicate, water, and optionally an alkali base. The first aluminosilicate

[0031] The first aluminosilicate may be chosen from metakaolins (i.e. calcined kaolins), fly ash, blast furnace slag, swelling clays such as bentonite, calcined clays, any type of compound comprising aluminium and silica fume, zeolites, and mixtures thereof.

[0032] Among these compounds, metakaolins are preferred, especially those marketed by the company Imerys.

[0033] In the invention, the term "metakaolin" means calcined kaolin or dehydroxylated aluminosilicate. It is preferably obtained by dehydration of kaolin or kaolinite.

[0034] The geopolymer composition may comprise approximately 5 to 50% by weight of aluminosilicate, and preferably approximately 10 to 35% by weight of aluminosilicate, per relative to the total weight of the geopolymer composition.

[0035] The geopolymer composition may further comprise a second aluminosilicate different from the first aluminosilicate.

[0036] Preferably, the geopolymer composition comprises two calcined kaolins having different calcination temperatures.

[0037] According to a particularly preferred embodiment of the invention, the geopolymer composition comprises a first metakaolin selected from kaolins calcined at a temperature Tci of at least approximately 650°C, and a second metakaolin selected from kaolins calcined at a temperature Tc2 such that Tc2 - Tci > approximately 100°C, at least one first alkali silicate, water, and optionally an alkali base. The geopolymer composition can then exhibit improved mechanical properties, particularly in terms of flexibility and durability, while ensuring good reaction and fire resistance properties.

[0038] According to one embodiment of the invention, the first metakaolin is a kaolin calcined at a temperature Tci of at least about 700°C, and preferably of at least about 725°C.

[0039] According to a preferred embodiment of the invention, the first metakaolin is a kaolin calcined at a temperature Tci of at most about 875°C, and preferably of at most about 825°C.

[0040] The first metakaolin may comprise at least 20 mole percent about, and preferably at least 30 mole percent about, of aluminium oxide (Al2O3), relative to the total number of moles of the first metakaolin.

[0041] The first metakaolin may comprise at most about 60 mole percent, and preferably at most about 50 mole percent of aluminium oxide (Al2O3), relative to the total number of moles of the first metakaolin.

[0042] The first metakaolin may comprise at least about 35 mole percent, and preferably at least about 45 mole percent of silicon dioxide (SiO2), relative to the total number of moles of the first metakaolin.

[0043] The first metakaolin may comprise at most about 75% by mole, and preferably at most about 65% by mole of silicon dioxide (SiO2), relative to the total number of moles of the first metakaolin.

[0044] As examples of first metakaolin, we can cite the metakaolins sold by the company Imerys, in particular that marketed under the reference PoleStar® 450.

[0045] The first metakaolin can be chosen from the calcined kaolins at Tci as defined in the invention, for at least 1 min about, preferably for at least 10 min about, particularly preferably for a period of approximately 30 min to 8h, and more particularly preferably for a period of approximately 2h to 6h.

[0046] The second metakaolin is preferably chosen from kaolins calcined at a temperature Tc2 such that Tc2 - Tci > approximately 150°C, particularly preferably such that Tc2 - Tci > approximately 200°C, and even more particularly preferred such that Tc2 - Tci > approximately 250°C.

[0047] According to one embodiment of the invention, the second metakaolin is a kaolin calcined at a temperature Tc2 of at least about 800°C, preferably of at least about 850°C, and particularly preferably of at least about 900°C.

[0048] According to a preferred embodiment of the invention, the second metakaolin is a kaolin calcined at a temperature Tc2 of at most about 1200°C, and preferably of at most about 1150°C.

[0049] The second metakaolin may comprise at least about 20 mole percent, and preferably at least about 30 mole percent of aluminium oxide (Al2O3), relative to the total number of moles of the second metakaolin.

[0050] The second metakaolin may comprise at most about 60 mole percent, and preferably at most about 50 mole percent of aluminium oxide (Al2O3), relative to the total number of moles of the second metakaolin.

[0051] The second metakaolin may comprise at least about 35 mole percent, and preferably at least about 45 mole percent of silicon dioxide (SiO2), relative to the total number of moles of the second metakaolin.

[0052] The second metakaolin may comprise at most about 75% by mole, and preferably at most about 65% by mole of silicon dioxide (SiO2), relative to the total number of moles of the second metakaolin.

[0053] As examples of second metakaolin, we can cite the metakaolins sold by the company Imerys, in particular the one marketed under the reference PoleStar® 200R.

[0054] The second metakaolin can be chosen from the kaolins calcined at Tc2 as defined in the invention, for at least 1 min about, preferably for at least 5 min about, particularly preferably for a period of approximately 10 min to 2h, and more particularly preferably for a period of approximately 15 min to 1h.

[0055] The mass ratio [first metakaolin / second metakaolin] in the geopolymer composition is preferably from 0.1 to about 2, particularly preferably from 0.5 to about 1.0, and most particularly preferably is about 1.

[0056] The geopolymer composition may comprise from 5 to 50% by weight approximately, and preferably from 10 to 35% by weight approximately, of first and second metakaolins, relative to the total weight of the geopolymer composition. The first alkali silicate

[0057] The first alkali silicate can be chosen from sodium silicates, potassium silicates, and one of their mixtures.

[0058] Alkaline silicates marketed by Silmaco or PQ Corporation are preferred. The first alkali silicate is preferably a sodium silicate.

[0059] The first alkali silicate can have a molar ratio SiO2 / M2O ranging from about 1.1 to about 35, preferably from about 1.3 to about 10, and particularly preferably from about 1.4 to about 5, with M being a sodium or potassium atom, and preferably a sodium atom.

[0060] The geopolymer composition may comprise from 5 to 60% by weight about, and preferably from 10 to 50% by weight about, of first alkali silicate, relative to the total weight of the geopolymer composition. The second alkali silicate

[0061] The geopolymer composition may further comprise a second alkali silicate different from the first alkali silicate.

[0062] The second alkali silicate may be chosen from sodium silicates, potassium silicates, and mixtures thereof. Alkaline silicates marketed by Silmaco or PQ Corporation are preferred. The second alkali silicate is preferably a sodium silicate.

[0063] The first and second alkali silicates may respectively have molar ratios SiO2 / M2O and SiO2 / M'2O such that M and M', identical, are chosen from a sodium atom and a potassium atom, and preferably a sodium atom, and said ratios have different values, preferably values ​​such that their difference is at least 0.3, particularly preferably such that their difference is at least 0.5, and even more particularly preferably such that their difference is at least 1.0.

[0064] According to one embodiment of the invention, the geopolymer composition comprises - a first alkali silicate having a SiO2 / M2O molar ratio ranging from approximately 1.5 to 2.6, and - a second alkali silicate having a molar ratio SiO2 / M'2O greater than 2.6, preferably ranging from about 2.8 to about 4.5, and particularly preferably ranging from about 3.0 to about 4.0, it being understood that M' is identical to M.

[0065] The geopolymer composition may comprise approximately 10 to 60% by weight, and preferably approximately 20 to 50% by weight of first and second alkali silicates, relative to the total weight of the geopolymer composition.

[0066] The mass ratio [first alkali silicate / second alkali silicate] in the geopolymer composition preferably ranges from 0.5 to 2.5, and particularly preferably from 0.8 to 2.0. The alkaline base

[0067] The alkaline base can be sodium hydroxide, or potassium hydroxide, and preferably sodium hydroxide.

[0068] The geopolymer composition may be free of alkaline base. This makes it possible to improve the handling of the geopolymer composition, particularly during the preparation of a cable.

[0069] The solids / water mass ratio in said geopolymer composition determines the solidification kinetics during steps i) to iii).

[0070] The geopolymer composition may comprise from 35% to 80% by weight approximately, and particularly preferably from 40% to 70% by weight approximately, of solid materials (alkali silicate(s), aluminosilicate(s) and alkaline base), relative to the total weight of said geopolymer composition.

[0071] The geopolymer composition may further comprise one or more additives selected from: - a dye, - mineral fibers, particularly those selected from alumina fibers, - a polymer structure additive, in particular selected from polyolefin fibers such as polypropylene fibers, high-density polyethylene (HDPE), aramids, and technical glass fibers coated with silicone or an organic polymer of the polyethylene type; a styrene-butadiene copolymer (SBR); a styrene-butadiene-ethylene (EBS) copolymer; derivatives of styrene-ethylene copolymers, in particular those marketed by Kraton such as a styrene-ethylene-butylene-styrene (SEBS) copolymer, a styrene-butadiene-styrene (SBS) copolymer, a styrene-isoprene-styrene (SIS) copolymer, a styrene-propylene-ethylene (EPS) copolymer or a styrene-ethylene-propylene-styrene (SEPS) copolymer; an ethylene-vinyl acetate (EVA) copolymer, a crosslinked polyorganosiloxane (egusing a peroxide); polyethylene possibly in powder form; lignosulfonates; cellulose acetate; other cellulose derivatives; a low viscosity silicone oil (e.g., around 12500 cPo); and a polyethylene oil. - a compound accelerating the setting of mass, in particular chosen from aluminium sulfate, alums (e.g., double sulfate of aluminium and potassium), calcium chloride, calcium sulfate, hydrated calcium sulfate, sodium aluminate, sodium carbonate, sodium chloride, sodium silicate, sodium sulfate, iron (III) chloride, and sodium lignosulfonates, - a setting retardant, in particular selected from ammonium, alkali metals, alkaline earth metals, borax, lignosulfonates and in particular calcium lignosulfonate metal salts, celluloses such as carboxymethyl hydroethyl cellulose, sulfoalkylated lignins such as sulfomethylated lignin, hydroxycarboxylic acids, copolymers of 2-acrylamido-2-methylpropane sulfonic acid salts and acrylic acid or maleic acid, and saturated salts, - an inert filler, notably chosen from talc, micas, dehydrated clays, and calcium carbonate, - a starch, - a starch plasticizer, in particular selected from a metal stearate, polyethylene glycol, ethylene glycol, a polyol such as glycerol, sorbitol, mannitol, maltitol, xylitol or an oligomer of one of these polyols, a sucrose such as glucose or fructose, a plasticizer containing amide groups, and any type of plasticizer based on modified polysaccharide(s), - a cellulose derivative, - an expanded carbon material such as expanded graphite.

[0072] The colorant is preferably a liquid colorant at room temperature (i.e. 18-25°C).

[0073] The geopolymer composition may comprise from 0.01 to 15% by weight approximately of additive(s), and preferably from 0.5 to 8% by weight approximately of additive(s), relative to the total weight of the geopolymer composition. Step i) of impregnation

[0074] Step i) can be carried out manually or automatically, and preferably it is carried out automatically.

[0075] Step i) is preferably carried out by impregnation coating, and particularly preferably by pre-controlled coating.

[0076] Step i) can for example be carried out using a coating device such as a coating die.

[0077] Step i) can be carried out more particularly by passing the non-woven fibrous material through a coating device such as a coating die, said device being supplied with the geopolymer composition, notably by means of a pump, preferably equipped with means for regulating the feed rate. This makes it possible to distribute the required quantity of the geopolymer composition directly and homogeneously over the entire desired width of said material to obtain effective, sufficient, and appropriate impregnation of the tape.

[0078] Step i) may in particular be a coating of the type known by the anglicism "tensioned web die coating".

[0079] In a preferred embodiment of the invention, the impregnation step i) is carried out at a temperature ranging from approximately 15°C to 90°C, and particularly preferably from approximately 20°C to 40°C. Step ii) drying

[0080] Step ii) implements the drying of the impregnated tape obtained in the previous step i).

[0081] Step ii) can advantageously be carried out at a temperature of no more than approximately 120°C. A temperature of 120°C or less can, in particular, prevent the composition from hardening before it is formed into a roll in step iii). In this context, it is preferable that the temperature at which step ii) is carried out be no more than 115°C, or even no more than 110°C (in particular, no more than 107°C).

[0082] Step (ii) can also advantageously be carried out at a temperature of at least approximately 50°C. A temperature of 50°C or higher promotes rapid drying. If it is desired to further reduce the drying time, step (ii) can be carried out at a temperature of at least approximately 60°C, or even at least 70°C, for example at a temperature of 80°C or higher (in particular, 90°C or higher).

[0083] Step ii) is preferably carried out at a temperature of approximately 70 to 115°C, and particularly preferably at approximately 90 to 107°C.

[0084] Step ii) brings the geopolymer composition from a liquid state to a semi-paste state. Typically, the geopolymer composition at the end of step ii) comprises at least one phase in the form of an aluminosilicate gel.

[0085] Step ii) can for example be carried out using one or more ovens, in particular one or more Infrared ovens.

[0086] Step iii) of forming the roll from the ribbon

[0087] In step iii), the partially impregnated and dried ribbon obtained at the end of step (ii) is typically shaped to provide a roll where the ribbon is wound around itself around an axis perpendicular to its longitudinal axis.

[0088] The winding of the ribbon in step iii) is typically carried out by rotating the end of the ribbon (typically around a cylindrical drum-type part), which drives the rest of the ribbon around the axis of rotation. It is preferable to maintain the ribbon under tension, preferably at a constant tension, particularly to optimize its winding.

[0089] The linear speed of the ribbon during the winding of step (iii) is advantageously constant, this constant linear speed being able for example to be obtained by regulating the rotation speed by means of a servo system linked for example to a measurement of the linear speed of the ribbon or of the tension of the ribbon.

[0090] It is also advantageous to keep the faces of the tape parallel to the axis around which it is wound, so as to prevent the tape from bending, slipping, or even breaking. To this end, the tape can advantageously be guided between guiding devices. (rollers, idler pulleys, for example, maintaining parallelism).

[0091] Once the roll of tape has been prepared according to step iii), said roll can be easily stored or transported, particularly when packaged in an airtight bag or similar waterproof envelope which, in addition to preventing the setting of the geopolymer composition between steps (iii) and (i)

[0092] The preparation of the roller used in the process according to the invention is preferably carried out continuously. In other words, steps i) to iii) described above are preferably carried out continuously.

[0093] For the purposes of this description, the concept of a series of steps performed "continuously" means that said steps are carried out on a single production line, and / or without rest or recovery steps. In other words, in the process according to the invention, there are no intermediate rest steps between the distribution of the nonwoven fibrous material and the recovery / obtaining of the roll at the end of step (iii).

[0094] When steps i), ii) and iii), are carried out continuously, they are typically implemented concurrently, by circulating the non-woven fibrous material on a production line from a reserve of fibrous material (delivered in the form of a tape from a dispenser such as a reel or unwinder) and ending in a roll preparation area, and where each portion of the circulating fibrous material tape is first subjected to step i) in a first area of ​​the production line, then subjected to step ii) in a second area of ​​the production line, and finally being formed into a roll in the roll preparation area.

[0095] Steps i), ii) and iii) can be implemented to manufacture several rolls of the invention in succession. In this case, steps i), ii) and iii) can be carried out continuously for the preparation of each roll, with a stoppage of the production line between each roll, but a process without stopping the production line can also be envisaged, by equipping the line with an accumulator at the infeed and outfeed.

[0096] Preferably, step i) is implemented by passing the nonwoven fibrous material in tape form through a coating device fed with the geopolymer composition at a flow rate D (in kg / min). The distributor delivers the nonwoven fibrous material at a speed V (in km / min), with a D / V ratio typically ranging from about 20 to 50 kg of geopolymer composition / km of nonwoven fibrous material, and particularly preferably from about 25 to 40 kg of geopolymer composition / km of nonwoven fibrous material. The amount of geopolymer composition applied to the nonwoven fibrous material can thus be easily controlled by a pump.

[0097] The speed V is preferably identical to the speed of cable movement.

[0098] The flow rate D can typically range from approximately 0.5 kg / min to 1.8 kg / min.

[0099] The speed V can typically range from approximately 20 m / min to 50 m / min.

[0100] During step ii), the transformation from the liquid state to the paste state requires a significant amount of energy. The use of several ovens, particularly successive ones along the production line, makes it possible to optimize the drying of the impregnated ribbon (in terms of exposure time, speed V and amount of energy delivered).

[0101] According to a particularly preferred embodiment of the invention, the non-woven fibrous material passes through the coating device to carry out step i), then the resulting impregnated tape passes through one or more ovens, preferably through several ovens arranged successively one after the other to carry out step ii), then the partially dried impregnated tape is wound onto itself according to step iii) to form a roll which is typically stored and / or transported to another site for the implementation of step iv).

[0102] Step 5iv) of applying the tape around the cable

[0103] In step iv), the tape is dispensed from the roll, which is unwound, and the unwound tape is applied around said cable comprising at least one elongated electrically conductive element. According to the invention, the application of the partially dried, impregnated tape around the cable is typically carried out by wrapping the tape around the cable.

[0104] This wrapping of the tape around the cable, which generally aims to cover the cable along its entire length by means of the tape, is typically carried out:

[0105] - along the longitudinal axis of the cable, namely with a winding of the ribbon around the cable with the longitudinal axis of the ribbon parallel to the longitudinal axis of the cable, the ribbon then being folded around the cable in the direction of its width (the ribbon then closes on the cable with generally little overlap of the faces of the ribbon on each other, typically with overlap areas of about 10 to 20%);

[0106] or

[0107] - according to a helical winding, namely with a winding of the ribbon around the cable with the longitudinal axis of the ribbon which is neither parallel nor perpendicular to the longitudinal axis of the cable, the ribbon then forming a helix around the cable (the ribbon then covering the cable with generally little overlap of the faces of the ribbon from one turn of the helix to the next typically with overlap areas of about 10 to 20%).

[0108] Advantageously, the winding is helical in step iv).

[0109] Step iv) can be carried out manually or automatically, and preferably automatically.

[0110] When the winding of the tape around the cable is carried out along the longitudinal axis of the cable, step iv) is advantageously implemented by passing the partially dried impregnated tape (unwound from the roll) through a tightening device or a tape forming device initiating its folding around the cable in its width direction (device referred to hereafter as "trumpet"). The cable comprising at least one elongated electrically conductive element then also passes through the tightening device during step (i), which allows the partially dried impregnated tape to be continuously wound around the elongated electrically conductive element, which facilitates the longitudinal winding of the impregnated tape around the cable, and thus forms said composite layer surrounding said elongated electrically conductive element.

[0111] When the winding of the tape around the cable is helical, step iv) is advantageously implemented by winding the tape around the elongated electrically conductive element, with the longitudinal axis of the tape forming an angle typically between 20 and 70° with the longitudinal axis of the cable and driving the cable in rotation and translation to ensure the continuous winding of the tape in the form of a helix around the cable. The composite layer

[0112] The composite layer is preferably an electrically insulating layer.

[0113] In the present invention, the term "electrically insulating layer" means an layer whose electrical conductivity can be at most 1.109 S / m, and preferably at most 1.10 10 S / m (siemens per meter) (at 25°C).

[0114] The composite layer is preferably a fire-retardant and / or fire-resistant layer.

[0115] The composite layer preferably has a thickness of approximately 0.2 to 3 mm, and particularly preferably of approximately 0.5 to 1 mm.

[0116] When the thickness of the composite layer is less than 0.2 mm, the thermal protection of the cable obtained according to the process of the invention is not sufficient.

[0117] The composite layer of the invention is preferably a ribboned layer (i.e. in the form of a ribbon or strip).

[0118] The composite layer preferably has a substantially constant thickness and constitutes in particular a continuous protective envelope.

[0119] The composite layer may in particular comprise 2 to 3 superimposed ribbons.

[0120] The composite layer of the invention is preferably non-porous.

[0121] The composite layer is preferably an internal layer of said cable.

[0122] According to the invention, the term "inner layer" means a layer that does not constitute the outermost layer of the cable.

[0123] The composite layer preferably comprises at least one geopolymer material and the non-woven fibrous material as defined in the invention. The geopolymer material

[0124] In the present invention, the geopolymer material is obtained from a geopolymer composition as defined in the invention, preferably by hardening, geopolymerization and / or polycondensation of said geopolymer composition.

[0125] In particular, the geopolymer composition as defined in the invention is capable of forming said geopolymer material. The ingredients of the geopolymer composition can therefore undergo polycondensation to form said geopolymer material. Hardening occurs through an internal polycondensation reaction. Hardening is not, for example, the result of simple drying, as is generally the case for binders based on alkali silicates.

[0126] Indeed, geopolymer materials result from a mineral polycondensation reaction by alkaline activation, known as geosynthesis, as opposed to traditional hydraulic binders in which hardening is the result of hydration of calcium aluminates and calcium silicates.

[0127] In the present invention, the expression "geopolymer material" means a solid material comprising silicon (Si), aluminum (Al), oxygen (O) and at least one element selected from potassium (K), sodium (Na), lithium (Li), cesium (Cs) and calcium (Ca), and preferably selected from potassium (K), and sodium (Na).

[0128] The geopolymer material may be an aluminosilicate geopolymer material.

[0129] The aluminosilicate geopolymer material may be selected from poly(sialates) conforming to the formula (I) Mn(-Si-O-Al-O-)n [(M)-PS] and having a Si / Al molar ratio of 1, poly(sialate-siloxos) conforming to the formula (II) Mn(-Si-O-Al-O-Si-O-)n [(M)-PPS] and having a Si / Al molar ratio of 2, poly(sialate-disiloxos) conforming to the formula (III) Mn(-Si-O-Al-O-Si-O-Si-O)n [(M)-PSDS] and having a Si / Al molar ratio of 3, and other poly(sialates) with a Si / Al ratio > 3, the aforementioned poly(sialates) comprising an alkali cation M selected from K, Na, Li, Cs and one of their mixtures, and n denotes the degree of polymerization.

[0130] In one embodiment, the geopolymer material represents from 5 to 98% by weight approximately, preferably from 55 to 95% by weight approximately, and preferably still from 65 to 90% by weight approximately, relative to the total weight of the composite layer.

[0131] The process may further include, before step i), a step i0) of preparing the geopolymer composition comprising mixing said first aluminosilicate with said first alkali silicate, water, and optionally the alkali base.

[0132] Step i0) is generally carried out at a high pH, ​​in particular ranging from 10 to 13.

[0133] Step i0) preferably comprises the following substeps: ioi) a substep for preparing an aqueous solution of the first alkali silicate, And i02) a substep of mixing the first aluminosilicate in powder form with the aqueous solution of alkali silicate prepared in the previous substep iOi).

[0134] The aqueous solution of the first alkali silicate can be prepared by mixing silicon dioxide SiO2 or an alkali silicate with a MOH base in which M is K or Na.

[0135] Silicon dioxide SiO2 can be selected from silica fume (i.e. fumed silica), quartz, and mixtures thereof.

[0136] Substep i01) can be carried out by dissolving the base in water, resulting in the release of heat (exothermic reaction), and then adding the silica (or the alkali silicate). The heat released then accelerates the dissolution of the silica (or the alkali silicate) during substep i01), and of the first aluminosilicate during substep i02).

[0137] When the second aluminosilicate and / or the second alkali silicate as defined in the invention exists(s), step i0) of preparing the geopolymer composition may include mixing said first aluminosilicate and optionally said second aluminosilicate, with said first alkali silicate, optionally said second alkali silicate, water, and optionally the alkali base.

[0138] Step i0) preferably comprises mixing the first and second metakaolins, with the first alkali silicate and optionally the second alkali silicate, water, and optionally an alkali base.

[0139] The first and second metakaolins and the first and second alkali silicates are as defined in the invention.

[0140] According to a preferred embodiment, step i0) comprises the following substeps: iOa) the mixing of the first and second alkali silicates, especially under stirring, iOb) possibly the addition of an alkali base, especially while maintaining stirring, and iOc) the addition of the first and second metakaolins, notably by maintaining agitation.

[0141] At the end of step i0), or substep i02) or iOc), a fluid and homogeneous solution is preferably obtained.

[0142] At the end of step i0), the geopolymer composition may comprise from 35% to 80% by weight approximately, and particularly preferably from 40% to 70% by weight approximately, of solid materials (alkali silicate(s), aluminosilicate(s) and alkaline base), relative to the total weight of said geopolymer composition.

[0143] Such a mass ratio allows for a geopolymer composition that is fluid enough to allow handling, and whose solidification kinetics are quite slow to allow the formation of a cable layer as defined below.

[0144] The solids / water mass ratio in said geopolymer composition can be used to determine the solidification kinetics of said geopolymer composition.

[0145] After step i0) of preparing the geopolymer composition, and before step i) of impregnation, the geopolymer composition can be heated, in particular to a temperature ranging from approximately 55°C to 95°C, and particularly preferably from approximately 70°C to 90°C. This makes step i) easier.

[0146] The method may further include, after step iv), a step v) of applying an external protective sheath around the composite layer. The external protective sheath may ensure the mechanical integrity of the cable.

[0147] At the end of step v), the cable may then comprise at least one elongated electrically conductive element, the composite layer surrounding said elongated electrically conductive element, and at least one outer protective sheath surrounding said composite layer.

[0148] Step v) is preferably carried out by extrusion, in particular at a temperature ranging from approximately 140°C to 195°C.

[0149] Step v) can for example be carried out using an extruder.

[0150] In this embodiment, an extrusion head can be positioned at the outlet of the forming device as defined in the invention.

[0151] The outer protective sheath is preferably the outermost layer of the cable.

[0152] The outer protective sheath is preferably an electrically insulating layer.

[0153] The outer protective sheath is preferably made of a material free from halogen. It can be made conventionally from flame-retardant or flame-resistant materials. In particular, if these materials do not contain halogen, it is referred to as HFFR type cladding (for "Halogen Free Flame Retardant").

[0154] The outer protective sheath may comprise at least one organic or inorganic polymer.

[0155] The choice of organic or inorganic polymer is not limiting and these are well known to those skilled in the art.

[0156] According to a preferred embodiment of the invention, the organic or inorganic polymer is chosen from crosslinked and non-crosslinked polymers.

[0157] The organic or inorganic polymer may be a homo- or a co-polymer having thermoplastic and / or elastomeric properties.

[0158] Inorganic polymers can be polyorganosiloxanes.

[0159] Organic polymers can be polyurethanes or polyolefins.

[0160] Polyolefins can be selected from ethylene and polymers Propylene. Examples of ethylene polymers include linear low-density polyethylene (LLDPE), low-density polyethylene (LDPE), medium-density polyethylene (MDPE), high-density polyethylene (HDPE), ethylene-vinyl acetate (EVA) copolymers, ethylene-butyl acrylate (EBA) copolymers, methyl acrylate (EMA) copolymers, 2-hexylethyl acrylate (2HEA) copolymers, ethylene-alpha-olefin copolymers such as polyethylene-octene (PEO), ethylene-propylene (EPR) copolymers, ethylene-propylene (EPT) terpolymers such as ethylene propylene diene monomer (EPDM) or mixtures thereof.

[0161] The polymer of the outer protective sheath is preferably an organic polymer, preferably more preferably an ethylene polymer, and more preferably a copolymer of ethylene and vinyl acetate, a linear low-density polyethylene, or a mixture thereof.

[0162] The outer protective sheath may further comprise a hydrated, flame-retardant mineral filler. This hydrated, flame-retardant mineral filler acts primarily through physical means by decomposing endothermically (e.g., releasing water), thereby lowering the temperature of the sheath and limiting the propagation of flames along the cable. These properties are referred to as flame retardant properties.

[0163] The hydrated flame-retardant mineral filler can be a metal hydroxide such as magnesium hydroxide or aluminum trihydroxide.

[0164] The outer protective sheath may further include an inert filler, in particular selected from talc, micas, dehydrated clays and one of their mixtures.

[0165] Advantageously, the cable obtained according to a process according to the invention satisfies at least one of the reaction or non-propagation standards to fire selected from EN 60332-1, EN 60332-3, and EN 50399 (2012 / 02 + Al 2016); and preferably EN 50399 (2012 / 02 + Al 2016), in particular the classification criteria B2ca, sla, dO, al of said standard, and possibly EN 60332-1 and EN 60332-3.

[0166] According to one embodiment of the invention, the cable is a power and / or telecommunications cable, and preferably an electrical cable.

[0167] When the cable comprises a plurality of elongated electrically conductive elements, the composite layer can then surround the plurality of elongated electrically conductive elements of the cable.

[0168] The cable may comprise a single composite layer as defined in the invention or a plurality of composite layers as defined in the invention.

[0169] When the cable comprises a plurality of composite layers, the process can ty (puncture understand the repetition of step iv), as many times as there are composite layers to be applied (with, where appropriate, identical or different rolls of tape for each of the layers made), then possibly step v) as defined in the invention.

[0170] Preferably, the cable comprises a single composite layer, and more particularly preferably a single internal composite layer, namely that said composite layer does not constitute the outermost layer of the cable, which typically corresponds to the implementation of a single step iv) followed by a single step v).

[0171] Preferably, step (iv) (or steps (iv) when several successive steps are implemented) and step (v) are carried out continuously. According to this embodiment, there are no intermediate resting steps between the distribution of the nonwoven fibrous material from the partially impregnated and dried tape roll and the retrieval / obtaining of the final cable.

[0172] When steps iv) and v), are carried out continuously, they are typically implemented concurrently, by circulating the partially unwound impregnated and dried tape from the roll on a production line starting from the roll and where each portion of the circulating fibrous material tape is first subjected at least once to step iv) in a first zone of the production line, and then advantageously subjected to step v) in a second zone of the production line, to form a cable according to the invention.

[0173] According to a particular embodiment of the invention, the cable obtained according to the process of the invention further comprises one or more layers interposed between the elongated electrically conductive element and the composite layer as defined in the invention.

[0174] These layers may comprise one or more polymer layers such as electrically insulating polymer layers, and / or one or more metallic layers such as metallic layers containing one or more openings.

[0175] In this case, the process further includes, before step iv), one or more steps of applying one or more of the layers mentioned above, around the elongated electrically conductive element, around the set of elongated electrically conductive elements, or around each of the elongated electrically conductive elements, depending on the type of cable desired.

[0176] Metallic layers containing one or more openings are typically layers used in radiating cables well known to those skilled in the art.

[0177] According to a preferred embodiment of the invention, the cable comprises: - a plurality of electrically conductive elements, each of said electrically conductive elements being surrounded by a polymer layer, in particular an electrically insulating one, to form a plurality of electrically conductive elements isolated, - a composite layer as defined in the invention surrounding said plurality of insulated electrically conductive elements, and - an external protective sheath, in particular electrically insulating, surrounding said composite layer.

[0178] The process according to the invention is fast, simple and economically advantageous. It makes it possible to manufacture in a few steps a cable with good mechanical properties, particularly in terms of flexibility and durability, while ensuring good fire resistance performance. Brief description of the drawings

[0179] The accompanying drawings illustrate one possible embodiment of the invention:

[0180] [Fig-1] Fig. 1 represents a schematic view of a device implementing a process conforming to the invention.

[0181] [Fig.2] Fig.2 represents a schematic view of an electrical cable as it can be obtained according to the process according to the invention.

[0182] For reasons of clarity, only the essential elements for understanding the invention have been represented schematically in the figures, without regard to scale.

[0183] Fig. 1 is a schematic illustration of a method according to the invention, corresponding to a continuous implementation of the manufacturing steps of the partially impregnated and dried tape roll, followed by a continuous implementation of the manufacturing steps of the cable from the roll.

[0184] Figure 1 shows a non-woven fibrous material 1 in the form of a ribbon placed on a dispenser 2. This ribbon material is unwound and conveyed from the dispenser onto a continuous roll production line. The roll contains the following elements, through which the ribbon passes successively: the moving ribbon first passes through a coating die 3 supplied with a geopolymer composition 4, in order to impregnate the material 1 with said composition 4 [according to step 1) of the invention]. The coating die 3 is typically connected to a pump (not shown in the diagram), advantageously associated with means for regulating the flow rate of composition 4. The impregnated ribbon exiting the coating die 3 then passes through an oven 5 (or more advantageously a series of ovens, according to a method not shown in the figure) in order to allow it to dry [according to step 2) of the invention].The partially dried, impregnated ribbon emerging from the oven is then conveyed to a winder 6 comprising a cylindrical shaft 7 driven in rotation by a motor not shown in the figure. The ribbon winds lengthwise around the generatrix of this cylinder to form an impregnated roll 8. and partially dried according to the invention, substantially cylindrical in shape around the axis serving as the central core of the roller. The winding of the ribbon around the axis 7 is also the origin of the overall movement imparted to the ribbon, which allows the continuous implementation of steps (i), (ii) and (iii) by driving the ribbon from the distributor towards the winder.

[0185] The process can be carried out to impregnate and dry all of the tape dispensed by the dispenser 2 and form it into a roll, or alternatively, to prepare at least one roll of partially impregnated and dried tape from only a portion of the dispensed tape. Once a roll of the desired size is obtained, it is typically removed from the winder (generally by cutting the tape at the winder inlet) and then advantageously packaged in an airtight bag.

[0186] The arrow shown in [Fig. 1] represents the storage and / or transfer of the roll 8 obtained, typically to a site other than the one implementing steps i) to iii).

[0187] The roller 8 is then used to make a cable according to steps iv) and v) of the invention carried out in a continuous mode.

[0188] To this end, the partially dried impregnated tape is unwound from the roll and then fed into a tightening device 9 together with a cable comprising an elongated electrically conductive element that is parallel to the longitudinal axis of the tape and located at the center of the tightening device. The tightening device then induces a folding of the tape upon itself in its widthwise direction, thereby trapping the cable along its length and forming a composite layer surrounding said elongated electrically conductive element [according to step iv)]. The cable thus obtained passes through an extrusion head 10 to form an outer protective sheath [according to step v)].

[0189] The [Fig.2] is a schematic representation of an electrical cable 10, corresponding to a fire-resistant electrical cable of type K25 or RZ1K.

[0190] This electrical cable 20 comprises four elongated electrically conductive elements 21, each being insulated with an electrically insulating layer 22, and, successively and coaxially around these four insulated elongated electrically conductive elements, a composite layer 23 as defined in the invention surrounding the four insulated elongated electrically conductive elements, and an outer sheath 24 of the HFFR type surrounding the composite layer 23 as defined in the invention, and advantageously takes the form of a ribbon.

[0191] The following examples, carried out on production lines corresponding to those illustrated in [Fig.1], illustrate one possible embodiment of the present invention. EXAMPLES

[0192] The raw materials used in the examples are listed below: - aqueous solution of a first sodium silicate at approximately 50% by weight of the "waterglass" type, Simalco, sodium silicate with a molar ratio SiO2 / Na2O of approximately 2.0, - aqueous solution of a second sodium silicate at approximately 38% by weight of the "waterglass" type, Simalco, sodium silicate with a molar ratio SiO2 / Na2O of approximately 3.4, - first metakaolin, PoleStar® 450, Imerys, with an Al2O3 / SiO2 molar ratio of 41 / 55 (i.e., approximately 0.745), kaolin calcined at a temperature of approximately 1000°C, - second metakaolin, PoleStar® 200R, Imerys, with an Al2O3 / SiO2 molar ratio of 41 / 55 (i.e., approximately 0.745), kaolin calcined at a temperature of approximately 700°C, and - non-woven material in Polyester, GT320, GECA TAPES.

[0193] Unless otherwise indicated, all these raw materials were used as received from the manufacturers. Example 1

[0194] Preparation of a roll of impregnated tape according to the invention

[0195] A geopolymer composition was used in this example, which was prepared as follows: an aqueous solution of alkali silicates was prepared by mixing 40 g of a 50 wt% aqueous solution of a first sodium silicate and 40 g of a 38 wt% aqueous solution of a second sodium silicate. Then, 10 g of a first metakaolin and 10 g of a second metakaolin were mixed with the aqueous solution of alkali silicates. The geopolymer composition comprises approximately 55.2 wt% solids, relative to the total wt of said geopolymer composition.

[0196] The composition was used under the following conditions:

[0197] A non-woven polyester fibrous material in the form of a tape (width: 40 mm; thickness: 450 µm; length: 650 m) is continuously unwound from a dispenser at a speed of approximately 50 m / min. The tape passes along a production line as illustrated in [Fig. 1], and first passes through a coating die fed with the geopolymer composition by means of a pump delivering a constant flow rate of 1.5 kg / min, in order to allow the non-woven fibrous material to be impregnated by the geopolymer composition. The geopolymer composition has a temperature of approximately 40°C.

[0198] The impregnated ribbon then passes through three successive ovens in series: a first IR oven operating at a temperature of 800°C, then a second IR oven also operating at a temperature of 800°C connected immediately to the first, and finally again a third IR oven also operating at a temperature of 800°C, and connected immediately to the second oven, which allows drying impregnated tape.

[0199] At the end of the production line, the partially dried and impregnated ribbon is wound lengthwise onto itself to form a substantially cylindrical roll whose height along the generatrix is ​​equal to the thickness of the ribbon. The winding is carried out by wrapping the ribbon around a cylindrical cardboard support.

[0200] The resulting roll is packaged in a hermetically sealed bag suitable for long-term storage or even long-distance transport. Example 2

[0201] Preparation of a fire-resistant cable according to the invention

[0202] The partially dried impregnated tape roll obtained in Example 1 was used as the tape source in this example, under the following conditions.

[0203] The partially dried, impregnated tape, unwound from the roll, was fed into a tightening device through which a low-voltage cable passed, the longitudinal axes of the cable and the tape being parallel. This resulted in the impregnated tape being wound around the cable, the tape winding widthwise and enveloping the cable. The cable comprises five copper conductors with a cross-section of 1.5 mm², each conductor surrounded by an electrically insulating layer based on XLPE. Following the application of the impregnated tape around the cable, a composite layer surrounding the insulated conductors is obtained.

[0204] The composite layer thus formed has a thickness of 0.5 mm.

[0205] The resulting assembly is then covered by hot extrusion with a protective polymer sheath based on an HFFR mixture produced by NEXANS, consisting of polyethylene and flame-retardant fillers, said sheath having a thickness of approximately 2 mm. This yields a cable according to the invention. The flame performance of the cable is determined according to standard EN50399. Fifteen cable sections positioned on a vertical ladder are exposed to a 20 kW flame for 20 minutes.

[0206] The results are reported in Table 1 below:

[0207] [Tables 1] Performance parameters; Class values ​​according to PHkR (kW) 133 82 Time at PC HRR (s) 31 ? THR (mL) V FIGRA GWs) 23.6 propagation of U danune (m) 036 Dripping. Inflamed None d0 SFR 0.03 if on SPR (?) [ .... J TABLE 1

[0208] In this table, the acronym HRR corresponds to the English expression "Heat Release Rate" which indicates the heat release rate, the acronym THR corresponds to the English expression "Total Heat Release" which indicates the amount of heat released during combustion, the acronym FIGRA corresponds to the English expression "Fire Growth Rate" which indicates the rate of fire growth, the acronym SPR corresponds to the English expression "Smoke Production Rate" which indicates the rate of smoke production, and the acronym TSP corresponds to the English expression "Total Smoke Production" which indicates the total amount of smoke produced.

[0209] These results demonstrate that the cable conforming to the invention has the maximum fire protection properties with regard to the requirements of the European standard EN50399.

Claims

Demands

1. A method for manufacturing a cable comprising at least one elongated electrically conductive element and at least one composite layer surrounding said elongated electrically conductive element, characterized in that the composite layer surrounding said elongated electrically conductive element is formed by applying around said cable a tape of fibrous material impregnated with a geopolymer composition, and wherein said impregnated and dried tape is delivered from a roll prepared according to the following steps: i) impregnating a non-woven fibrous material with a geopolymer composition, in order to form a tape impregnated with said geopolymer composition, ii) thermally treating the impregnated tape obtained in step i), in order to form a partially impregnated and dried tape, and iii) forming the roll by winding the partially impregnated and dried tape from step (ii) onto itself.

2. A method according to claim 1, characterized in that the non-woven fibrous material is selected from cellulosic materials, synthetic organic polymer-based materials, glass fibers, and one of their mixtures.

3. A process according to claim 1 or 2, characterized in that the geopolymer composition is an aluminosilicate geopolymer composition.

4. A method according to any one of claims 1 to 3, characterized in that step i) is carried out by passing the non-woven fibrous material through a coating device fed with the geopolymer composition, using feeding means preferably equipped with means for regulating the feed rate.

5. A method according to any one of claims 1 to 4, characterized in that step ii) is carried out at a temperature of no more than 120°C.

6. A method according to any one of claims 1 to 5, characterized in that step ii) is carried out at a temperature of at least 50°C.

7. A method according to any one of claims 1 to 6, characterized in that the application of the partially dried impregnated tape around a cable comprising at least one elongated electrically conductive element is carried out by winding the partially dried impregnated tape around the cable, carried out along the longitudinal axis of the cable.

8. A method according to any one of claims 1 to 6, characterized in that the application of the partially dried impregnated tape around a cable comprising at least one elongated electrically conductive element is carried out by winding the partially dried impregnated tape around the cable, carried out in a helical winding.

9. Roll of partially impregnated and dried tape comprising a tape of fibrous material impregnated with a geopolymer composition and partially dried, said partially impregnated and dried tape being wound on itself around an axis perpendicular to its longitudinal axis.

10. Roller according to claim 9, in the form of an assembly comprising a support around which the tape is wound upon itself.

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