Method for producing photocatalytic multicomponent fiber and photocatalytic multicomponent fiber

Abstract

The present invention relates to a method (100) for producing a photocatalytic multicomponent fiber, the method comprising the steps of: providing a support mixture (110) comprising at least one thermoplastic polymer; providing an active mixture (120) comprising at least one organic polymer, at least one photocatalyst at a concentration of at least 10% by weight based on the weight of the active mixture, and at least one coupling agent that is resistant to oxidation; spinning a multicomponent fiber from the support mixture and the active mixture (130); and removing the at least one organic polymer from the surface of the multicomponent fiber to produce a photocatalytic multicomponent fiber (160). The present invention also relates to multicomponent fibers, textile products, and filters.

Description

[Technical field]

[0001] The present invention relates to the field of textiles, in particular to the field of textile fibres.

[0002] The invention more particularly relates to a method for producing a photocatalytic multicomponent fiber, and to the photocatalytic multicomponent fiber itself. Furthermore, the invention relates to a textile product comprising a photocatalytic multicomponent fiber, and to a filter comprising at least one textile product according to the invention. [Background technology]

[0003] Known prior art is described below from which the present invention develops.

[0004] In recent years, air and water pollution continues to increase. The presence of organic or inorganic molecules in the air and / or water is closely monitored. In fact, air pollution has been proven to cause many diseases (e.g. cardiopulmonary diseases and certain cancers) on the one hand, but also to exacerbate environmental degradation and pollution. Similarly, water pollution (groundwater, lakes, rivers, seas, oceans) continues to increase to the point of causing damage to plants and animals. Also, many purification devices (air and / or water) have been developed. These devices are aimed in particular at removing pollutants, pathogens or allergens.

[0005] These purifiers generally work by physical methods, such as by filters or electrostatic precipitators, or by adsorption of contaminants onto materials (such as activated carbon), or by destruction or inactivation using ultraviolet light, or by photocatalysis. In some systems, several technologies are combined, and each purifier may have different advantages and risks.

[0006] In the field of air treatment, photocatalysts are materials capable of decomposing substances without emitting secondary pollutants. TiO2 is one of the most used photocatalysts. It is a semiconducting material that uses its properties regarding the absorption of light, more precisely light in the UV range, to enable various redox reactions, including in particular the decomposition of pollutants. Moreover, in addition to its strong photoactivity, TiO2 is a stable material that is highly produced and inexpensive, which is advantageous especially for industry.

[0007] The treatment process carried out by photocatalytic purification devices allows the decomposition and degradation of pollutants by the action of light rays on the surface of a photocatalyst, typically titanium dioxide (TiO2). This process destroys volatile organic compounds, inorganic pollutants and microorganisms. The final process essentially produces water and carbon dioxide.

[0008] For photocatalytic purification devices, the photocatalyst is generally deposited on the surface of a substrate. The photocatalyst can be deposited in the form of a powder, a suspension or a solution. This type of deposition on the surface of the substrate can lead to the formation of photocatalyst aggregates and only partial coverage with a low thickness. In this regard, the photocatalyst tends to easily detach from its substrate and the substrate on which the photocatalyst is deposited quickly becomes inactive.

[0009] Additionally, binders have been proposed that can be added to improve the adhesion of TiO2 to the substrate, however, such binders can significantly reduce the photocatalytic efficiency.

[0010] Finally, impregnating a surface with a mixture containing a photocatalyst may strongly alter the fluid dynamics at the impregnated surface, significantly reducing the photocatalytic efficiency and increasing the pressure drop within the air purifier.

[0011] Recently, it has been proposed to use composite fibers containing polymers and small amounts of photocatalysts to form filters for air purifiers. However, these techniques result in random trapping of the photocatalyst within the photocatalytic fibers, greatly reducing their efficiency. Thus, the fibers may contain TiO2 aggregates or, conversely, regions free of TiO2. In addition, the presence of aggregates within the polymer may hinder subsequent manufacturing steps such as spinning if the substrate is in the form of a fiber.

[0012] Moreover, currently, most of the substrates for fixing TiO2 include glass, ceramics, clay minerals, zeolites, metal plates, fibers from cellulose, or activated carbon fibers. However, these substrates are on the one hand very fragile and on the other hand very inflexible, which causes limitations on the geometry of the purification devices, which currently all look the same. In fact, during spinning, the fibers are pulled, heated, and cooled many times. As a result, the fibers may be damaged, such as cracked or broken. In particular, these fibers may be overstretched and suffer mass loss, pressure loss, and even force loss. This greatly limits the shaping and geometry of the textile products and thus the photocatalysts.

[0013] Moreover, during the industrialization process, it becomes very difficult to ensure good capacity and efficiency of photocatalysis based on fibers containing TiO2: on the one hand, it is necessary to incorporate a sufficient amount of photocatalyst into the fiber while ensuring sufficient fluidity of the matrix and uniform distribution of TiO2 during spinning to ensure good photocatalytic performance, and on the other hand, it is necessary to ensure optimal spinning while limiting pressure drop and maintaining the mechanical properties and handling of the fiber.

[0014] To overcome the problem of agglomerates and ensure optimal dispersion of TiO2, linear titanium oxide polymers have been proposed, for example, in document US2020282387. In this document, the coating is formed by sintering a solution containing the polymer, which can be deposited on a substrate in the form of fibers. In this document, however, the substrate is preferably rough and has a protruding outer surface. This makes it possible to improve the adhesion of TiO2 to the substrate, but the formation of TiO2 aggregates at the surface becomes prominent. Furthermore, sintering gives the structure a high rigidity, which reduces its workability and prevents any shaping operations. In addition, such products are very brittle and very prone to breakage, which limits the reduction of their thickness, especially to reduce the pressure drop.

[0015] Other techniques have also been developed, such as the method for producing macro-TiO2 fibers by continuous extrusion in a unidirectional flow described in document EP 3126550. Such a method allows the production of macro-TiO2 fibers on a large scale. However, in order to obtain good photocatalytic performance, the polymer is completely calcined after the production of the fibers, so that the fibers contain only TiO2 and are very brittle. Their mechanical resistance after calcination does not allow them to be subjected to a sufficiently powerful air flow for use in air purifiers.

[0016] The object of the present invention is to overcome the drawbacks of the prior art, in particular to propose a method for producing a multicomponent fiber with a high surface concentration of photocatalyst, with a uniform distribution of the photocatalyst, in order to optimize the efficiency of a photocatalytic air purifier using said fiber, while making it possible to provide a malleable textile product capable of supporting different shaping operations while maintaining a high breathability. Summary of the Invention

[0017] The present invention aims to overcome these drawbacks.

[0018] The present invention is particularly directed to a method for producing a photocatalytic multicomponent fiber, comprising the steps of: - providing a supported mixture, said supported mixture comprising at least one thermoplastic polymer or thermoplastic polymer precursor; - providing an active mixture, said active mixture comprising: at least one organic polymer or one organic polymer precursor, at least one photocatalyst in a concentration of at least 10% by weight relative to the weight of the active mixture, at least one coupling agent resistant to oxidation, preferably a silane, or a coupling agent precursor resistant to oxidation a process comprising: - spinning multicomponent fibers from the support mixture and the active mixture; - removing at least one organic polymer from the surface of the multicomponent fiber to produce a photocatalytic multicomponent fiber. The present invention relates to a method for producing a photocatalytic multicomponent fiber, comprising:

[0019] Applicants have developed a method that can produce multicomponent photocatalytic fibers with high photocatalyst loading and uniform surface distribution of photocatalyst while being deformable and possessing suitable mechanical properties for use in air purifiers. Indeed, the removal step can form an inorganic surface, preferably a mostly inorganic surface containing the photocatalyst in contact with the thermoplastic polymer support.

[0020] The Applicant has in particular developed a support mixture and an active mixture which, when combined, can ensure the production of soft fibres with a high photocatalyst content at the surface and a uniform distribution of the photocatalyst at the surface, such that photocatalyst agglomerates are reduced or absent and the fibre surface is mainly covered with photocatalyst.

[0021] Moreover, such a process also offers the possibility of spinning fibers without breaks, cracks or loss of strength.

[0022] Therefore, the method according to the present invention can meet the needs and in particular proposes the production of multicomponent photocatalytic fibers with a high surface concentration and uniform distribution of photocatalyst to optimize photocatalytic capacity and efficiency, and a porous multicomponent fiber surface with little or no agglomerates while being malleable to accommodate different shaping operations.

[0023] According to other optional characteristics of the method, the latter may optionally include one or more of the following characteristics, alone or in combination: - the removal of at least one organic polymer on the surface of the multicomponent fiber, including a surface calcination to generate an inorganic surface in contact with the thermoplastic polymer support, which on the one hand is capable of activating the photocatalyst and, on the other hand, provides the photocatalyst multicomponent fiber with a porous surface to improve its exchange with air while ensuring a uniform distribution; - the thermoplastic polymer or polymers of the support mixture are chosen from thermoplastic polymers having a melting temperature between 100°C and 350°C. These thermoplastic polymers of the support mixture are preferably bio-based and / or biodegradable; - it involves the extrusion and / or co-extrusion of the supporting mixture and / or the active mixture; - the support mixture and the active mixture have a hot flow index, measured according to the ISO 1133 standard, which differs not more than 20% between the melt flow index of the active mixture and the melt flow index of the support mixture. This allows for better control of the viscosity of the support mixture and the active mixture to ensure optimal spinning without breaks and / or loss of force. Furthermore, this can ensure optimized mechanical properties of the photocatalytic multicomponent fiber; During spinning, the multicomponent fibers are produced by mixing the following formula:

number

[0024] According to a second object, the present invention provides a photocatalytic multicomponent fiber, a thermoplastic polymer support, and - inorganic surface Including, The present invention relates to a photocatalytic multicomponent fiber in which the thermoplastic polymer substrate comprises at least one thermoplastic polymer and the inorganic surface comprises an oxidation resistant coupling agent and a photocatalytic network.

[0025] According to other optional properties of the photocatalytic multicomponent fibers, the latter may optionally include one or more of the following properties, either alone or in combination: - it has a diameter of less than 150 μm; the inorganic surface has a thickness of at least 500 nm;

[0026] According to a third object, the present invention relates to a textile product comprising at least one photocatalytic multicomponent fiber according to the invention, such a textile product according to the invention is soft and malleable.

[0027] According to a fourth object, the present invention relates to a filter comprising at least one textile product according to the invention. Such a filter, unlike existing filters, can have a variable shape, for example pleated. Furthermore, unlike existing filters, the filter according to the invention can be adapted, for example tailor-made.

[0028] According to a fifth object, the present invention relates to a photocatalytic air purifier comprising at least one filter according to the present invention, a ventilation system and an ultraviolet lighting system capable of illuminating the at least one filter, the ventilation device being arranged to transport air from an inlet of the purification system through the filter to an outlet of the purification system. [Brief description of the drawings]

[0029] Other characteristics and advantages of the invention will be better understood on reading the following description and on referring to the accompanying drawings, given by way of example and not of limitation, in which:

[0030] [Figure 1] FIG. 1 shows a diagram of a method for producing a photocatalytic multicomponent fiber according to one embodiment of the present invention. [Diagram 2] FIG. 2 shows a diagram illustrating different cross sections of a photocatalytic multicomponent fiber according to the present invention. [Diagram 3] FIG. 3 shows a scanning electron microscopy (SEM) photograph of a photocatalytic multicomponent fiber according to one embodiment of the present invention at 80x magnification.

[0031] The drawings are not necessarily drawn to scale, particularly thickness scale, for purposes of illustration.

[0032] Aspects of the present invention are described with reference to flowchart illustrations and / or block diagrams of methods and apparatus (systems) according to embodiments of the invention. In the drawings, flowcharts and block diagrams illustrate the structure, functionality, and operation of possible implementations of systems and methods according to various embodiments of the present invention. In some implementations, functions associated with the blocks may occur out of the order shown in the figures. For example, two blocks shown in succession may in fact be executed substantially simultaneously, or the blocks may be executed in the reverse order, depending on the functionality involved. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0033] In the following, we will first provide an overview of the invention and related terminology, then present the shortcomings of the prior art, and finally provide a more detailed description of how the present invention overcomes them.

[0034] In the remainder of the specification, the expression "multicomponent fibers" can correspond to bicomponent fibers, tricomponent fibers, or fibers of higher components.

[0035] The term "support mixture" may, within the meaning of the present invention, correspond to a mixture intended to form a network supporting the active mixture, the active mixture being supported on, around or within the support mixture. For example, in a sheath-core fiber structure, the support mixture may correspond to the fiber core.

[0036] The term "active mixture" within the meaning of the present invention can correspond to a mixture intended to form a preferably inorganic network on the surface of the support mixture and to interact with a physical stimulus during a photocatalytic reaction. For example, in a core-sheath fiber structure, the active mixture can correspond to the fiber sheath.

[0037] The term "core" may, within the meaning of the present invention, correspond to the inner part of the fiber, such as the core.

[0038] The term "sheath" may, within the meaning of the invention, correspond to the outer part of the fiber, such as for example the envelope.

[0039] The expression "thermoplastic polymer" refers, within the meaning of the present invention, to a polymer that can be repeatedly softened or melted under the action of heat and that can assume new shapes under the application of heat and pressure.

[0040] The expression "thermoplastic polymer precursor" may, within the meaning of the present invention, correspond to a component capable of initiating the polymerization reaction of one or more monomers.

[0041] The expression "organic polymer" may, within the meaning of the present invention, correspond to a linear, branched or cyclic polymer, the polymer core of which comprises at least one carbon atom.

[0042] The term "polymerization" may, within the meaning of the present invention, correspond to a process by which a monomer or a mixture of monomers can be converted into a polymer.

[0043] The term "predominantly" can, within the meaning of the present invention, correspond to at least 50%, preferably more than 50%. For example, a predominantly inorganic surface can, within the meaning of the present invention, correspond to a surface that contains more inorganic polymers by mass than organic polymers, or more inorganic molecules by molar than organic molecules. A predominantly inorganic surface can, for example, contain at least 50% by weight of photocatalyst and coupling agent.

[0044] The expression "resistant to oxidation" may, within the meaning of the present invention, correspond to a reduced or limited interaction with oxygen, capable of reducing redox reactions, in particular during photocatalysis.

[0045] The expression "substantially equal" can, within the meaning of the present invention, correspond to a value that varies less than 50%, preferably less than 40%, more preferably less than 30% compared to a comparison value. When substantially equal is used to compare values, the compared value varies less than 50%, preferably less than 40%, more preferably less than 30% compared to the value taken as the reference.

[0046] The present invention proposes to take into account existing challenges associated with cumbersome photocatalytic filters, which may in particular lead to pressure drop and / or reduced efficiency of the photocatalyst.

[0047] In particular, the present invention proposes a method for the manufacture of multicomponent fibers comprising a polymeric support in combination with an inorganic surface, preferably a predominantly inorganic surface, which allows the formation of fibers with high mechanical strength that can be shaped, without damaging the fibers, to form filters with a photocatalytic surface that combines high permeability with a high photocatalytic content compared to impregnated textile products with the same characteristics (fiber thickness, density, dimensions).

[0048] Accordingly, the present invention is directed to a method for making multicomponent fibers.

[0049] 1 shows an example of a method 100 for producing a photocatalytic multicomponent fiber. The method 100 includes a step 110 of providing a support mixture, a step 120 of providing an active mixture, a step 130 of spinning, and a step 160 of removing at least one organic polymer from the surface of the multicomponent fiber. Additionally, the method 100 according to the present invention may include a step 140 of forming a textile product and a step 150 of shaping the textile product.

[0050] In the example of Figure 1, the method 100 for producing a photocatalytic multicomponent fiber includes a step 110 of providing a support mixture. The support mixture includes at least one thermoplastic polymer. Alternatively, the support mixture includes at least one thermoplastic polymer precursor. According to another alternative, the support mixture includes at least one thermoplastic polymer and at least one thermoplastic polymer precursor.

[0051] The one or more thermoplastic polymers of the support mixture can be selected from thermoplastic polymers having a melting temperature of 350° C. or less, for example, a melting temperature of 100° C. to 350° C. Advantageously, the one or more thermoplastic polymers of the support mixture can be selected from polypropylene, polyester, polyethylene, polylactic acid, polyamide, polyvinyl, polyacrylate, polybutylene terephthalate, polyhydroxyalkanoate, poly(butylene adipate-co-terephthalate) and mixtures thereof. For example, the one or more thermoplastic polymers of the support mixture can be selected from polyethylene terephthalate, biopolyethylene terephthalate, biopolyethylene, biodegradable polyester and polyhydroxyalkanoate.

[0052] Preferably, the one or more thermoplastic polymers of the support mixture may be selected from bio-derived and / or biodegradable thermoplastic polymers.

[0053] The thermoplastic polymer precursors according to the invention for the support mixture can be chosen, for example, from all thermoplastic polymer precursors having a melting temperature between 100° C. and 350° C. Advantageously, the thermoplastic polymer precursor or precursors can be chosen from lactides, acrylates, methacrylates, styrenes and / or lactones.

[0054] Advantageously, the one or more thermoplastic polymers of the support mixture and / or the one or more thermoplastic polymers formed from the thermoplastic polymer precursors of the support mixture have good properties for spinning.

[0055] The step of providing a support mixture can include, for example, preparing a support mixture. In this embodiment, when the support mixture includes a precursor, such as at least one thermoplastic polymer monomer, the step of preparing the support mixture can include a polymerization step. The polymerization step can be performed using a stimulus, such as a plasma, ion bombardment, an electrochemical process, a chemical species (nucleophile, electrophile, etc.), light radiation, etc. Furthermore, the polymerization step can be performed at a predetermined time and temperature depending on the at least one monomer.

[0056] The step of preparing the supported mixture may be carried out at a temperature of 100°C or more and up to 400°C.

[0057] Optionally, the process of preparing the support mixture can include the addition of additives, for example to improve the durability of the flexible support, for example a photocatalytic multicomponent fiber core in the form of a sheath-core fiber structure.

[0058] The method 100 of making a photocatalytic multicomponent fiber includes a step 120 of providing an active mixture.

[0059] The active mixture comprises at least one organic polymer, such as at least one thermoplastic polymer. Alternatively, the active mixture comprises at least one organic polymer precursor. According to another alternative, the active mixture comprises at least one organic polymer and at least one organic polymer precursor.

[0060] The polymer or polymers of the active mixture may be selected from polymers having a melting temperature between 100° C. and 350° C. Advantageously, the polymer or polymers of the active mixture may be selected from polypropylene, polyester, polyethylene, polylactic acid, polyamide, polyvinyl, polyacrylate, polybutylene terephthalate, polyhydroxyalkanoate, poly(butylene adipate-co-terephthalate) and mixtures thereof. For example, the polymer or polymers of the active mixture may be selected from polyethylene terephthalate, biopolyethylene terephthalate, biopolyethylene, biodegradable polyester and polyhydroxyalkanoate.

[0061] Preferably, the polymer or polymers of the active mixture may be selected from bio-derived and / or biodegradable thermoplastic polymers.

[0062] Additionally, one or more of the polymers of the active mixture may contain additional chemical groups grafted thereto.

[0063] The polymer precursors of the active mixture according to the invention can be chosen, for example, from all polymer precursors having a melting temperature between 100° C. and 350° C. Advantageously, the polymer precursor or precursors can be chosen from lactides, acrylates, methacrylates, styrenes and lactones.

[0064] In certain embodiments of the present invention, providing an active mixture may include a step of preparing an active mixture.

[0065] The step of preparing the active mixture may be carried out at a temperature up to 400°C and up to 100°C.

[0066] When the preparation of the active mixture includes at least one thermoplastic polymer monomer, the step of preparing the active mixture can include a polymerization step. The polymerization step can be performed using stimuli such as plasma, ion bombardment, electrochemical processes, chemical species (nucleophiles, electrophiles, etc.), light radiation, etc. Furthermore, the polymerization step can be performed at a predetermined time and temperature depending on the at least one monomer.

[0067] In certain embodiments of the present invention, the active mixture includes the same polymer or polymer precursor as the supporting mixture.

[0068] Advantageously, the polymer(s) of the active mixture, preferably the thermoplastic polymer and / or the polymer(s) formed from the polymer precursor, preferably the thermoplastic polymer, have good properties for spinning.

[0069] The active mixture comprises at least one photocatalyst. Preferably, the active mixture comprises at least one photocatalyst in a concentration of at least 10% by weight, preferably at least 15% by weight, at least 20% by weight, at least 25% by weight, at least 30% by weight, at least 35% by weight, at least 40% by weight, based on the weight of the active mixture. Preferably, the active mixture comprises a photocatalyst in a concentration of 50% by weight or less, preferably 45% by weight or less, based on the weight of the active mixture. For example, the photocatalyst or photocatalysts will be present in the active mixture in a concentration of 10% to 50% by weight, preferably 15% to 45% by weight, more preferably 20% to 45% by weight, even more preferably 25% to 40% by weight, based on the weight of the active mixture. The photocatalyst can be administered with a gravimetric dispenser.

[0070] The photocatalyst may be selected within the meaning of the present invention from transition metals, base metals, metalloids and their oxides, preferably those having photocatalytic properties.For example, the photocatalyst may be selected from AgBr, AgCl, Ag3PO4, Ag2S, AgI, Bi2O3, Bi2S3, C3N4, CdS, CdSe, CdO, Ce2O3, Ce2S3CoO, CuO, Cu2O, Cu2S, CulnS2, FeTiO3, Fe2O3, GaAs, GaP, In2S3, MoS2Nn2O3, NiO, PbO, PdO, RuO2, SnO2, SnS, TiO2, V2O5, WS2WO3, ZnO, ZnS, ZrS2, ZnSe, ZrO2 and mixtures thereof.

[0071] The photocatalyst may optionally be doped and / or grafted. For example, the photocatalyst may be pretreated with a hydrophobizing treatment.

[0072] Preferably, the photocatalyst is TiO2.

[0073] The photocatalyst may be in a crystalline form. In the particular case of TiO2, said photocatalyst may be in the form of anatase, or a mixture of anatase and rutile, or a mixture of anatase, rutile and brookite.

[0074] The photocatalyst may be in the form of nanoparticles with an average diameter of 2 nm to 100 nm, preferably 5 nm to 75 nm, more preferably 10 nm to 50 nm. The photocatalyst may be in the form of a powder or a precursor in solution.

[0075] According to one embodiment, the photocatalyst is incorporated into the active mixture when it is in the molten state, which limits and minimizes the formation of agglomerates.

[0076] The active mixture comprises at least one coupling agent or coupling agent precursor. Preferably, the coupling agents according to the invention are resistant to oxidation.

[0077] The coupling agent may include chemical functional groups capable of forming chemical bonds with at least one photocatalyst, preferably TiO2. The coupling agent may include chemical functional groups that allow a polymerization reaction of the coupling agent to form a network. The coupling agent may include chemical functional groups capable of forming chemical bonds with the thermoplastic polymer of the support mixture.

[0078] The coupling agent may be selected from one or more geopolymers or one or more geopolymer precursors.

[0079] The coupling agent may be selected, for example, from a silane or a siloxane.

[0080] Preferably, the coupling agent is vinyltrimethoxysilane, polydimethylsiloxane, tetraethoxysilane, tetramethoxysilane, tetrapropoxysilane, n-propyltriethoxysilane, ethyltrimethoxysilane, methyltriethoxysilane, propyltrimethoxysilane, propyltriethoxysilane, phenyltrimethoxysilane, phenyltriethoxysilane, trimethoxyvinylsilane, triethoxyvinylsilane, vinyltriethoxysilane, vinyltris(β-methoxy ethoxy)silane, β-(3,4-epoxycyclohexyl)ethyltrimethoxysilane, γ-(2-aziridine)aminopropyltrimethoxysilane, γ-glycidoxypropyltrimethoxysilane, γ-glycidoxypropyltrimethyldiethoxysilane, γ-glycidoxypropyltriethoxysilane, γ-methylpropenylpropyldimethoxysilane, γ-methylpropenyltrimethoxysilane, γ-methylpropenylpropyldiethoxysilane, γ-methylpropenylpropyltriethoxy Silane, N-β(aziridine)γ-aminopropylmethyldimethoxysilane, N-β(aziridine)γ-aminopropyltrimethoxysilane, N-β(aziridine)γ-aminopropyltriethoxysilane, N-β-(aminoethyl)-γ-aminopropyltrimethoxysilane, 3-acryloxypropyltrimethoxysilane, 3-aminopropyltrimethoxysilane, 3-aminopropyltriethoxysilane, N-phenyl-γ-aminopropyltrimethoxysilane, γ-chloropropyltrimethoxysilane The coupling agent is selected from silane, γ-hydrothiopropyltrimethoxysilane, bis[3-(triethoxysilyl)propyl]tetrasulfide (TESPT) and bis[3-(triethoxysilyl)propyl]-disulfide, preferably 3-acryloxypropyltrimethoxysilane, 3-chloropropyltrimethoxysilane, 3-mercaptopropyltrimethoxysilane, 3-methacryloxypropyltrimethoxysilane, 3-acryloxypropyltrimethoxysilane and combinations thereof. These coupling agents allow good charge distribution and simplify the compounding process. Preferably, the coupling agent allows the formation of an inorganic network structure and is able to withstand photocatalysis.Preferably, the inorganic network is crosslinked. It preferably comprises polymer chains linked together by bonds of lower molecular weight, so that it can form a three-dimensional network. Advantageously, the inorganic network is able to withstand oxidation and thus photocatalysis.

[0081] The coupling agent precursor may be selected from silica, siloxane, silanol.

[0082] The active mixture comprises at least one coupling agent at a concentration of at least 0.75% by weight, preferably at least 1.5% by weight, at least 2% by weight, at least 2.5% by weight, at least 3% by weight, based on the weight of the active mixture. Preferably, the active mixture comprises at least one coupling agent at a concentration of 10% by weight or less, preferably at a concentration of 8% by weight or less, based on the weight of the active mixture. For example, the active mixture comprises at least one coupling agent at a concentration of 0.75% to 10% by weight, preferably at least 1.5% to 8% by weight, based on the weight of the active mixture.

[0083] Advantageously, adding a coupling agent to the active mixture can reduce the viscosity of the active mixture compared to the viscosity of the same active mixture without the coupling agent, measured with a rheometer according to the ISO 1628 standard.

[0084] The active mixture may include at least one coupling agent with a mass ratio of at least one photocatalyst in the range of 1 / 50 to 5 / 1. Preferably, the active mixture may include at least one coupling agent with a mass ratio of at least one photocatalyst in the range of 1 / 20 to 2 / 1. More preferably, the active mixture may include at least one coupling agent with a mass ratio of at least one photocatalyst in the range of 1 / 10 to 1.

[0085] According to one embodiment, the coupling agent is incorporated into the active mixture by injection using a pump, for example a peristaltic pump.

[0086] Preferably, the photocatalyst used in the context of the present invention is pre-combined with a coupling agent.Accordingly, according to a preferred embodiment of the present invention, the coupling agent is added to the active mixture when combined with the photocatalyst.Accordingly, in this case, the method can include a step of combining the photocatalyst with a coupling agent or a step of providing the photocatalyst combined with a coupling agent.

[0087] The step of providing the support mixture and / or the step of providing the active mixture can be carried out by means of a mixer (compounder), kneader, extruder and / or a gravimetric type dispenser and / or a volumetric dispenser.

[0088] In a preferred embodiment, the step of providing a support mixture and / or the step of providing an active mixture comprises extrusion and / or co-extrusion. The step of providing a support mixture and / or the step of providing an active mixture can comprise multi-stage extrusion. The multi-stage can be two or more stages. The multi-stage extrusion can improve the dispersion of the photocatalyst and the incorporation of the coupling agent in the active mixture.

[0089] When the step of providing the support mixture includes extruding the support mixture, the extrusion step is configured so that the support mixture has a melt flow index (MFI) measured according to the ISO 1133 standard (measured at 230° C. on a standard weight of 2160 g) that is substantially equal to the melt flow index of the active mixture. For example, the support mixture has a melt flow index (MFI) that differs from the melt flow index of the active mixture by no more than 20%, preferably no more than 10%, and more preferably no more than 5%. Thus, the difference between the MFI of the support mixture and the MFI of the active mixture is small, preferably no more than 15%.

[0090] The melt flow index of the active mixture may be, for example, 5 g / 10 min to 1500 g / 10 min, as measured according to the ISO 1133 standard. For example, the melt flow index of the support mixture may be 9 g / 10 min to 15 g / 10 min. In one embodiment, the MFI of the support mixture may be 12 g / 10 min and the MFI of the active mixture may be 27 g / 10 min. In another embodiment, the MFI of the support mixture may be 12 g / 10 min and the MFI of the active mixture may be 5 g / 10 min. In another embodiment, the MFI of the support mixture may be 12 g / 10 min and the MFI of the active mixture may be 11 g / 10 min.

[0091] The step of preparing the active mixture may be carried out at a temperature of at least 100°C up to 400°C, preferably at no more than 300°C, more preferably at no more than 250°C.

[0092] The method 100 for making a photocatalytic multicomponent fiber can include a spinning step 130. The spinning step is preferably performed from a support mixture and an active mixture.

[0093] The spinning process can be carried out under heat by melt spinning (for quenching on a wheel), spunbond (for cold drawing) and / or meltblown (for hot drawing).

[0094] Figure 2 shows examples of spinning structures according to the present invention, illustrating some of the possible structures, with a sheath-core structure in Figure 2A, an islands-in-the-sea structure in Figure 2B, and a side-by-side structure in Figure 2C.

[0095] The structures shown in Figures 2A and 2B make it possible to form one or more fibers comprising a core-type thermoplastic polymer support 11 and an inorganic, preferably mostly inorganic, surface 12 of an inorganic sheath type. As shown in Figure 2B, the multicomponent fiber may comprise three phases: a thermoplastic polymer support 11, an inorganic, preferably mostly inorganic, surface 12, and a sacrificial matrix 13. Indeed, in certain embodiments, the multicomponent fiber may comprise a sacrificial matrix, which is typically removed prior to the step of removing the at least one organic polymer.

[0096] As shown in FIG. 2C, the multicomponent fiber may include a substrate 11 in contact with an inorganic, preferably predominantly inorganic, surface 12 .

[0097] Additional drawing steps can be performed under low and / or high temperature conditions to reduce the diameter of the resulting wire.

[0098] Preferably, the spinning process can be carried out to achieve a fiber diameter of between 2 μm and 150 μm.

[0099] In order to avoid damage such as cracks, breaks, or loss of mass or strength, the spinning process is carried out such that the fibers have a diameter as determined by microscopy (SEM) of the following formula:

number

number

[0100] Advantageously, the spinning process can be carried out by melting and can include hot drawing, which can be carried out using at least one extruder comprising one or more heating zones. Preferably, the melt spinning process comprises an extruder for the support mixture and an extruder for the active mixture.

[0101] The spinning process can be configured to vary the ratio (e.g., mass) of the support mixture to the active mixture. This can reduce the diameter of the fiber, e.g., vary the core to sheath ratio of a sheath-core fiber. Furthermore, the fibers obtained by the support and active mixture preparation process have a uniform texture during the spinning process (measured by SEM microscopy), showing good charge dispersion and uniform distribution of the photocatalyst on the surface. The fibers can be air-cooled and directly wound up.

[0102] The spinning process may also include a drawing step. Drawing can be preferably carried out at a temperature between the glass transition temperature and the melting temperature of the polymer of the supporting mixture and / or the active mixture. In this embodiment, after uncoiling and passing through a first drawing bench at a speed V1, the fiber is reheated, preferably at 80°C to 140°C, and drawn again at a speed V2 using a second drawing bench before being rewound. The draw ratio V2 / V1 can vary the diameter. Drawing can reduce the diameter of the fiber and improve its mechanical properties.

[0103] The method 100 for making multicomponent fibers can include forming the multicomponent fibers into a textile product 140. Forming the multicomponent fibers into a textile product 140 may or may not include a weaving or knitting step.

[0104] The process of forming the textile 140 can be done from a single multicomponent fiber, multiple multicomponent fibers, or a sheet of multicomponent fibers. The textile formed can correspond to a flat tubular shape and some other three-dimensional pattern of nonwoven or woven fabric. As with other textile structures, various properties can be incorporated into the mesh to meet design goals. Design goals can include increased flexibility, increased strength, reduced caliper, improved handling, and increased mechanical strength.

[0105] The method 100 for making a multicomponent fiber can include a step 150 of shaping a fiber product, which can have a variety of shapes due to the flexibility of multicomponent fibers that include thermoplastic polymers.

[0106] The method 100 for making a multicomponent fiber includes a step 160 of removing at least one polymer, preferably an organic polymer, from the surface of the multicomponent fiber. The removing step can produce a photocatalytic multicomponent fiber. Advantageously, the removing step includes a surface treatment of the multicomponent fiber.

[0107] Preferably, the step of removing at least one polymer (preferably an organic polymer) on the surface of the multicomponent fiber can generate an inorganic surface, preferably a mostly inorganic surface, in contact with the thermoplastic polymer support. This allows, for example, to form an inorganic sheath surrounding a thermoplastic polymer core in a sheath-core fiber structure. The generated inorganic surface, preferably a mostly inorganic surface, can include the presence of an organic polymer. However, the remaining organic polymer will be a minority by weight of the inorganic surface. In practice, the inorganic surface preferably comprises at least 50% by weight of the photocatalyst and coupling agent.

[0108] The step of removing at least one polymer (preferably an organic polymer) at the surface may comprise a heat treatment, a chemical treatment, a plasma, preferably localized, i.e. on the surface of the multi-fiber component. Preferably, the treatment is capable of removing at least a portion of the organic polymer from the active mixture over a depth of at least 500 nm, more preferably at least 1 μm, even more preferably at least 2 μm. Preferably, the treatment is capable of removing at least a portion of the organic polymer from the active mixture over a depth of up to 50 μm, more preferably up to 30 μm, even more preferably up to 20 μm. For example, the removal step may decompose at least a portion of the at least one organic polymer of the active mixture over a depth of 500 nm to 50 μm, preferably 1 μm to 30 μm, even more preferably 2 μm to 20 μm.

[0109] In the particular embodiment shown in connection with FIG. 2B, the sacrificial matrix may also be removed prior to the removing step 160 by chemical, thermal or plasma treatment.

[0110] Furthermore, the step of removing at least one polymer, preferably an organic polymer, from the surface of the multicomponent fiber may be partial or complete, with partial removal corresponding to limited removal of one or more organic polymers throughout the depth of the multicomponent fiber.

[0111] The heat treatment may be selected from UV (ultraviolet) or IR (infrared) radiation treatment, convection heating, conduction heating. Preferably, the heat treatment comprises calcination. The heat treatment is preferably localized at the surface, more preferably extending to a depth of at least 500 nm. The heat treatment may be carried out at a temperature between 350° C. and 550° C. The heat treatment may be applied for a period of 0.5 hours to 7 hours.

[0112] The chemical treatment can be selected from those processes using reactive species in solid, liquid or gas form that are capable of removing the polymer from the active mixture, for example, treatment in an oxygen-rich water-type oxidizing liquid.

[0113] Plasma treatment generally involves the ionization of a gas, for example by applying an electric or magnetic field to the gas to form a plasma capable of oxidizing the surface of the multicomponent fiber.

[0114] The removal of the surface, preferably the organic polymer, can increase the level of photocatalyst on the surface, which can increase the efficiency of the photocatalytic reaction, and therefore greatly improve the photocatalytic properties of the multicomponent fiber.

[0115] In accordance with another aspect, the present invention relates to a photocatalytic multicomponent fiber.

[0116] The multicomponent photocatalytic fiber according to the invention can be obtained by the method according to the invention. Preferably, it is directly obtained by the method according to the invention.

[0117] The multicomponent fibers include a substrate comprising at least one thermoplastic polymer and an inorganic surface, preferably a predominantly inorganic surface.

[0118] In certain embodiments, photocatalytic multicomponent fibers according to the present invention comprise a thermoplastic polymer core and an inorganic sheath.

[0119] In any embodiment, the photocatalytic multicomponent fiber can include at least one intermediate sheath, preferably between the core and the sheath. The intermediate sheath can include another thermoplastic polymer, an inorganic material (e.g., silica), and / or a coupling agent. For example, the intermediate sheath can help protect the core and extend the life of the multicomponent fiber. The multicomponent fiber can also include a sacrificial matrix.

[0120] The thermoplastic polymer core of the multicomponent fiber comprises a thermoplastic polymer. The polymer core of the multicomponent fiber may comprise an additive. The thickness of the core of the multicomponent fiber may be in the range of 1 μm to 150 μm.

[0121] The sheath of the multicomponent fiber comprises a network of oxidation-resistant coupling agent and photocatalyst, preferably a silica-titanium network. The surface thickness of the photocatalyst is preferably between 300 nm and 20 μm. Advantageously, the sheath of the multicomponent fiber is at least 50% inorganic, preferably at least 60%, more preferably at least 70%, even more preferably at least 80%. The sheath of the multicomponent fiber may be less than 100% inorganic, for example preferably less than 95%. Advantageously, the inorganic sheath has at least 5% by weight of photocatalyst, preferably at least 10% by weight of photocatalyst, preferably at least 15% by weight of photocatalyst, more preferably at least 20% by weight of photocatalyst, even more preferably at least 25%. For example, the inorganic sheath has less than 95% by weight of photocatalyst, preferably less than 90% by weight of photocatalyst, even more preferably less than 85% by weight of photocatalyst, preferably after removal of the organic polymer from the active mixture. The thickness of the sheath of the multicomponent fiber can be in the range of 300 nm to 20 μm. The thickness, preferably the diameter, of the photocatalytic multicomponent fiber according to the present invention is 150 μm or less, preferably 100 μm or less, more preferably 50 μm or less, and even more preferably 10 μm or less. For example, the thickness, preferably the diameter, of the photocatalytic multicomponent fiber is at least 1 μm.

[0122] Preferably, the multicomponent fibers have a predominantly inorganic surface thickness of 500 nm or greater.

[0123] The multicomponent fibers have a surface. Preferably, the surface of the multicomponent fibers is compositionally uniform (as shown by MEB / EDX, Energy Dispersive X-ray). Preferably, after treatment, the multicomponent fibers are porous and have a thickness of at least 10 mm. 2 / g (measured by BET analysis). The specific surface area of ​​multicomponent fibers is up to 500 m 2 Preferably, the specific surface area of ​​the multicomponent fiber is 10 m 2 / g~500m 2 / g range.

[0124] According to another aspect, the present invention relates to a textile product comprising at least one photocatalytic multicomponent fiber according to the present invention.

[0125] The textile according to the invention can correspond to a textile that can be used in any field, such as, for example, the clothing, decoration or industrial fields. It can be used in water and / or air treatment methods, in particular via photocatalysis, for water and / or air purification or due to its antibacterial and self-purifying properties. Such textiles can also preferably participate in the destruction of volatile organic compounds.

[0126] Advantageously, the textile according to the invention is deformable to have different shapes.The textile according to the invention is therefore flexible, especially before the step of removing at least one polymer, preferably an organic polymer, on the surface.Deformation is possible by folding, twisting or twisting without breaking the textile or losing photocatalytic efficiency.The filter according to the invention therefore has increased efficiency and photocatalytic activity.

[0127] According to another aspect, the present invention relates to a filter comprising at least one textile product according to the invention.

[0128] According to another aspect, the present invention relates to a photocatalytic fluid purification device comprising at least one filter according to the present invention. The fluid can be, for example, air or water, preferably air. Preferably, the filter is located between the fluid inlet and the fluid outlet of the purification device.

[0129] The purification device may also include a ventilation system.

[0130] The ventilation system can be arranged to transport the fluid from the inlet of the purifier to the outlet of the purifier. The ventilation system is arranged in particular to generate an air flow passing through the filter according to the invention. The ventilation system can for example comprise at least one ventilator with one or more propellers, blades and / or turbines which can be arranged at different positions. Preferably, the ventilation system is arranged so that the air flow leaving the purifier, preferably filtered, contains reduced levels of VOCs, allergens, pollutants and / or pathogens compared to the air entering the purifier. Advantageously, the speed of the ventilation system can be adjusted. Different power levels of the purifier can thus be defined. This allows for example to increase the power of the purifier in heavy pollution cases without having to operate the purifier continuously at maximum power.

[0131] The purification device may also include a lighting system.

[0132] The lighting system preferably comprises an ultraviolet lighting system capable of illuminating at least one filter according to the invention. Preferably, the wavelength of the lighting system is comprised in one or more of the ranges UVA, UVB and / or UVC, i.e. in the range 100-400 nm. Advantageously, the lighting system can be centered on one or more bands, for example 100 nm-280 nm, 280 nm-320 nm, 320 nm-400 nm, or other bands that can be centered on UVA and UVB or UVB and UVC, or other combinations between UVA, UVB, UVC. The UV radiation can activate the photocatalyst. The lighting system can, for example, comprise a UV lamp.

[0133] The purification device may include one or more sensors, which may be, for example, a pressure sensor, a contamination sensor, a temperature sensor, a particle detection sensor, a concentration sensor, a consumption sensor, and an obstruction sensor.

[0134] The purification device may include a processing module configured to adjust the speed of a ventilation system and / or the intensity of a lighting system.

[0135] The purifier may include a communication module configured to communicate between the one or more sensors and the ventilation system and / or the lighting system via a communication network. The communication module may be configured to emit a message including, for example, at least one indication of a measured pressure differential, a filter blockage level, an indication of a contamination level, an indication of a contamination removal level, a type of particle detected, an abnormal temperature rise within the purifier, and / or an abnormal current draw of the purifier. EXAMPLES

[0136] component Thermoplastic polymer of the support mixture: polypropylene Organic polymer of active mixture: Polypropylene Photocatalyst: TiO2 40%, Crystal form: Mixture of anatase and rutile Coupling agent: Polysiloxane

[0137] combination The compounding is carried out using a co-kneader with mixing capabilities, which may be a single screw co-kneader or a twin screw co-kneader driven by a rotational and translational motion.

[0138] A co-mixer may contain multiple (gravimetric and / or volumetric) dispensers and one or more heating zones.

[0139] The polymer, coupling agent and optional additives of the active mixture are introduced into the co-kneader using a hopper to produce a dry mixture, and the photocatalyst is introduced using a gravimetric dispenser in a transverse feed to ensure incorporation of the molten photocatalyst.

[0140] A second gravimetric dispenser is filled with the active mixture.

[0141] The support mixture may also be produced using a single or twin screw extruder.

[0142] The mixing is carried out at a temperature of 150 to 300°C.

[0143] spinning Once mixing is complete, the spinning process is carried out using a transport belt and one or more bobbins. The speed of each extruder can vary the ratio of polymer of the support mixture to polymer of the active mixture.

[0144] The mechanical property measurements of the fibers are carried out according to the ISO 5079 standard.

[0145] As shown in Figure 3, the photocatalytic multicomponent fibers according to the invention are much more homogeneous in composition, have a high photocatalytic loading and few aggregates (MEB). Thus, they can provide more active material even at coverages of more than 25%. Moreover, although their diameter shrinks in the presence of the drawing process, good mechanical properties are maintained. In fact, the fibers are more flexible and more resistant, but with a diameter of less than 150 μm.

[0146] Furthermore, when the preparation process includes a prior step of grafting the photocatalyst with a coupling agent, the draw ratio is optimized (8 vs. 6) and the diameter is also reduced.

[0147] The photocatalytic multicomponent fibers according to the present invention have improved mechanical properties: the multicomponent fibers have optimized flexibility and improved malleability.

[0148] [Table 1]

[0149] The present invention may be subject to numerous modifications and applications other than those described above. In particular, unless otherwise specified, the different structural and functional characteristics of each of the above-described implementations should not be considered as combined with each other and / or as closely and / or inseparably related to each other, but rather as simple juxtapositions. Furthermore, the structural and / or functional characteristics of the different embodiments described above may be subject to any different juxtapositions or any different combinations in whole or in part.

Claims

1. A method (100) for producing a photocatalytic multicomponent fiber, comprising the steps of: providing (110) a support mixture, the support mixture comprising at least one thermoplastic polymer or thermoplastic polymer precursor; Providing an active mixture (120), said active mixture comprising: at least one organic polymer or one organic polymer precursor; at least one photocatalyst in a concentration of at least 10% by weight relative to the weight of the active mixture; At least one oxidation-resistant coupling agent, preferably a silane, or an oxidation-resistant coupling agent precursor a process comprising: spinning (130) multicomponent fibers from the support mixture and the active mixture; removing (160) the at least one organic polymer from the surface of the multicomponent fiber to produce a photocatalytic multicomponent fiber; A method (100) for producing a photocatalytic multicomponent fiber, comprising:

2. 10. The method (100) for producing a photocatalytic multicomponent fiber of claim 1, wherein the removal of the at least one organic polymer from the surface of the multicomponent fiber comprises surface calcination to produce an inorganic surface in contact with the thermoplastic polymer support.

3. The method (100) for producing a photocatalytic multicomponent fiber according to claim 1 or 2, characterized in that one or more thermoplastic polymers of the support mixture are selected from thermoplastic polymers having a melting temperature of 100°C to 350°C.

4. 3. A method (100) for producing a photocatalytic multicomponent fiber according to claim 1 or 2, characterized in that the method (100) for producing a photocatalytic multicomponent fiber comprises extrusion and / or co-extrusion of the supporting mixture and / or the active mixture.

5. During spinning, the multicomponent fibers are formed from a polymer having the following formula: [Equation 1] The method for producing a photocatalytic multicomponent fiber (100) according to claim 1 or 2, characterized in that the coverage calculated according to the formula (100) is 5% to 50%.

6. A photocatalytic multicomponent fiber, a support mixture corresponding to a thermoplastic polymer support comprising at least one thermoplastic polymer; and Active mixtures corresponding to inorganic surfaces Including, A photocatalytic multicomponent fiber, wherein the inorganic surface comprises a photocatalytic network structure of a coupling agent resistant to oxidation and a photocatalyst, and the photocatalytic multicomponent fiber is spun by combining the support mixture and the active mixture.

7. The photocatalytic multicomponent fiber according to claim 6, characterized in that the photocatalytic multicomponent fiber has a diameter of 150 μm or less.

8. 8. The photocatalytic multicomponent fiber of claim 6 or 7, characterized in that the photocatalytic multicomponent fiber has an inorganic surface that is at least 500 nm thick.

9. A textile product comprising at least one photocatalytic multicomponent fiber according to claim 6 or 7.

10. A filter comprising at least one textile product according to claim 9.

11. 11. A photocatalytic air purifier comprising at least one filter according to claim 10, a ventilation system, and an ultraviolet lighting system capable of illuminating the at least one filter, the ventilation system being arranged to transport air from an inlet of the purification system through the filter to an outlet of the purification system.

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