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    • 专利摘要:
    Multilayer filter with antimicrobial properties and its use in respirator and protective mask applications. The present invention is framed in the area of polymeric materials applied to the sector of manufacturing materials for use in filters for respirators and protective masks. In particular, the invention relates to multilayer filters for respirators and protective masks that can be biodegradable and that comprise filter materials based on ultrafine fibers obtained by electro-hydrodynamic and aerohydrodynamic processing and that exercise passive protection of the FFP1, FFP2 type., N95 and FFP3 and that can also be washable and have antimicrobial active properties. (Machine-translation by Google Translate, not legally binding)
    公开号:ES2765374A1
    申请号:ES202030319
    申请日:2020-04-20
    公开日:2020-06-08
    发明作者:Cabello José María Lagarón；Figuerez María De Las Mercedes Pardo；Flor Alberto Chiva
    申请人:Consejo Superior de Investigaciones Cientificas CSIC；Bioinicia SL；
    IPC主号:
    专利说明:

    [0002] Multilayer filter with antimicrobial properties and its use in respirator and protective mask applications
    [0004] The present invention is framed in the area of polymeric materials applied to the sector of manufacturing materials for use in filters for respirators and protective masks. In particular, the invention relates to multilayer filters for respirators and protective masks that can be biodegradable and that comprise filter materials based on ultrafine fibers obtained by electro-hydrodynamic and aero-hydrodynamic processing and that exercise passive protection of the FFP1, FFP2 type. , N95 and FFP3 and that can also be washable and have antimicrobial active properties.
    [0006] BACKGROUND OF THE INVENTION
    [0008] Absorption of airborne pollutants from high concentrations in the body can be potentially very dangerous and can be absorbed by the body through the skin, eyes or respiratory system. Absorption of airborne pollutant particles into the lungs through the respiratory system is prone to both acute and chronic health risks, especially when these include pathogens of infectious respiratory diseases, such as tuberculosis and measles, and emerging diseases such as severe acute respiratory syndrome (SARS) and the H1N1 A flu.
    [0010] In these cases, the size of the contaminants is important. In general, smaller particles are more likely to be airborne and more dangerous. Thus, particles larger than 10 ^ m are generally collected in the upper part of the respiratory system. Therefore, most of them cannot enter the deep part of the lungs. However, particles smaller than 10 ^ m are breathable, which means they are able to penetrate deep into the lungs. Those particles include, but are not limited to, bacteria, viruses, clay, slime, tobacco smoke, and metal fumes.
    [0012] The danger of air pollutants can be managed by applying basic controls, such as increasing ventilation or providing workers with protective equipment, such as protective masks.
    [0014] Protective masks have been widely used by staff in hospitals, laboratory researchers, construction site workers, as well as the general public in highly contaminated areas or during the flu season.
    [0016] Protective masks are generally made up of a filter barrier, which is a critical component that determines the level of protection of the mask, since the filtration efficiency depends on the particle size and the speed of the air flow.
    [0018] Most of the filter barriers of conventional protective masks are not functionalized with biocides or virucides, so these protective masks simply serve as a physical barrier to filter out contaminants, and in most cases do not have the ability to stop microorganisms as small as viruses, which are between 100 and 200 nm in size. Furthermore, when these contaminants are viruses and bacteria, these barriers also do not remove them from the tissue with which they come into contact. Therefore, the microorganisms attached to the masks can survive for several hours, greatly increasing the risk of cross infection. Finally, since the known filters are made of non-biodegradable materials, in the case of a massive use of masks by the non-medical population, as in the case of a pandemic, they can end up generating a serious environmental problem.
    [0020] DESCRIPTION OF THE INVENTION
    [0022] The present invention proposes a methodology to generate a multilayer filter based on ultrafine fibers, and its use in respirators and protective masks, which have a combination of materials, their arrangement, morphology and grammage of the fibers that gives them the balance of properties necessary to reach levels of filtration to paraffin aerosols, called FFP1 (out of every 100 viruses, only 20 pass maximum), FFP2 and N95 (out of every 100 viruses, only 6 pass maximum) and FFP3 (out of 100 viruses, only 1 passes maximum) ); and maintaining maximum resistance levels to inhalation respiration over 55 cm2 areas, with an air flow of 30 l / min, less than 1.1 millibar, and with an air flow of 85 l / min, less than 3.5 millibars. These masks can additionally contain antimicrobial substances, be washable and can also have compostability and biodegradability properties in the environment.
    [0024] Therefore, a first aspect of the present invention refers to a multilayer filter characterized in that it comprises at least:
    [0025] i) An internal layer (a) that is in contact with the user's skin, characterized in that it is composed of filtering polymeric materials, and that has a surface density of at least 0.01 g / m2, more preferably between 5 and 3000 g / m2, even more preferably between 20 and 300 g / m2;
    [0026] ii) An intermediate layer (b) characterized in that it is composed of polymeric fibers, which optionally contains antimicrobial substances, and which have a surface density of at least 0.01 g / m2, more preferably between 0.1 and 10 g / m2; and even more preferably between 0.2 and 3 g / m2;
    [0027] iii) an outer layer (c) characterized in that it is composed of filtering polymeric materials, and that it has a surface density of at least 0.01 g / m2, more preferably between 5 and 3000 g / m2; and even more preferably between 20 and 300 g / m2.
    [0029] In a preferred embodiment, the polymeric materials constituting the inner layer (a) and the outer layer (c) of the filter are selected, without limitation, from non-water-soluble proteins such as keratin, polysaccharides such as cellulose, cottons and in general any fiber natural, and waxes or paraffins, polyhydroxyalkanoates (PHA) such as PHB, PHV, medium chain lenght PHA (mcl-PHA), and all its possible copolymers such as, for example, PHBV, poly- £ -caprolactone (PCL) and all its copolymers such as PEG-PCL and PCLA, polylactic acid (PLA), all its copolymers such as PGLA, polyphosphazenes, polyorthoesters, polyesters obtained from natural precursors such as polytrimethylene terephthalate (PTT), polybutylene terephthalate ( PBT), polybutylene succinate (PBS), and all possible copolymers of these such as poly (butylene adipate-co-terephthalate) (PBAT), among others, as well as other non-biodegradable polymers, such as p or example: polyolefins from which ethylene-based polymers and copolymers can be highlighted, such as for example polyethylene, propylene, polyethylene-co-vinyl acetate (EVA), polyethylene terephthalate (PET) and copolymers thereof, silicones, polyesters, polyurethanes (PURs), polysulfones, halogenated polymers such as for example vinylidene polyfluoride (PVDF ), ethylene polytetrafluoride (PTFE) or polyvinylidene polychloride (PVDC), polyvinylidene polychloride (PVC), polycarbonates, acrylonitrile butadiene styrene, latex, polyimides, polysulfones, and polyamides such as PA6, PA66 or PA69, PA1010, as well as mixtures of any of the above, or any of the above mixed with additives such as plasticizers, surfactants, antioxidants, colorants, etc.
    [0031] In a more preferred embodiment the polymeric material that make up the inner layer (a) and the outer layer (c) are independently selected from polypropylene, polyamide, polyester, natural fibers, cotton, and cellulose, or any combination thereof.
    [0033] In another preferred embodiment the materials of the constituent fibers of the intermediate layer (b) are polymers selected from among halogenated polymers such as polyvinylidene fluoride and its copolymers, polytetrafluoride ethylene, polyvinylidene polychloride, polyacrylonitrile, polysulfones and their derivatives, polylactic acid , polyurethanes and their derivatives, polyamides, cross-linked polyvinyl alcohol, polyvinyl butyral, polyhydroxyalkanoates such as poly (3-hydroxybutyrate-co-3-hydroxyvalerate), polystyrene, polyvinyl acetate, polyethylene terephthalate, chitosan, polycarbonates, polymethylmethallyne , or any of its combinations.
    [0035] In another preferred embodiment, the polymers of the constituent fibers of the intermediate layer (b) are selected from polyvinylidene, polyacrylonitrile, and polyhydroxyalkanoates, or any combination thereof. In an even more preferred embodiment, the polymers that make up the intermediate layer (b) of the filter of the invention are polyhydroxyalkanoates.
    [0037] In another preferred embodiment the polymers of the fibers constituting the intermediate layer (b) have a molecular weight of less than 800 kDalton, more preferably less than 300 kDalton, and even more preferably less than 200 kDalton.
    [0039] In another preferred embodiment, the intermediate layer (b) contains particles, nanoparticles or liquids of a selected antimicrobial substance, without limitation, from among zinc oxide, silver, silver nitrate, copper, copper oxide, carbonaceous materials such as graphene, carbon micro and nanotubes, titanium oxide and dioxide, extracts natural and essential oils, chitin and chitosan, aluminum oxide, silicon dioxide (SiO2), cyclodextrins (CD), antibiotics and antivirals such as tetracycline, iodine, triclosan, chlorhexidine, acyclovir, cyclophloxacin, or combinations thereof. In a more preferred embodiment the antimicrobial substance is zinc oxide; in an even more preferred embodiment the antimicrobial substance contained in the intermediate layer (b) are zinc oxide nanoparticles.
    [0041] In another preferred embodiment, the inner layer (s) (a) and / or outer layer (s) (b) contain particles, nanoparticles or liquids of an antimicrobial substance selected, without limitation, from oxide of zinc, silver, silver nitrate, copper, copper oxide, carbonaceous materials such as graphene, carbon micro and nanotubes, titanium oxide and dioxide, natural extracts and essential oils, chitin and chitosan, aluminum oxide, silicon dioxide (SiO2), cyclodextrins (CD), antibiotics, and antivirals such as tetracycline, iodine, triclosan, chlorhexidine, acyclovir, cycloofloxacin, or combinations thereof. In a more preferred embodiment the antimicrobial substance is zinc oxide; in an even more preferred embodiment the antimicrobial substance contained in the intermediate layer (b) are zinc oxide nanoparticles.
    [0043] In another preferred embodiment the content by weight of the antimicrobial in the fibers in each of the layers is less than 50%, more preferably less than 25% and even more preferably less than 13%. It is known that in general to kill viruses you have to add an order of magnitude more of the antimicrobial substance than to kill bacteria.
    [0045] In this invention the term "antimicrobial substance" refers to an agent that kills microorganisms or stops their growth. Microorganisms encompass heterogeneous single-celled organisms, not evolutionarily related to each other, such as bacteria (prokaryotes), protozoa (eukaryotes, some filum of algae ) and unicellular fungi, and also includes ultramicroscopic acellular biological entities such as viruses and prions.The antimicrobial scope of this invention focuses mainly on bacteria, fungi, and especially all types virus.
    [0047] In another preferred embodiment the fibers of the intermediate layer (b) are fibers of smooth or pearl morphology.
    [0049] In another preferred embodiment the intermediate layer (b) comprises an additional layer. This additional layer (b ') may contain the same polymer as that of the first intermediate layer (b) on which it is deposited, or it may be composed of fibers of a different polymer. Likewise, the morphology of both polymers that make up each of the two intermediate layers (b and b ') may have the same or different morphology, and, likewise, may have the same or different surface density.
    [0051] In an even more preferred embodiment, the additional intermediate layer (b ') is composed of the same polymer, with the same morphology and has the same surface density as the polymer of the intermediate layer (b).
    [0053] In another preferred embodiment the intermediate layer (b) has a fiber morphology with an average diameter of between 10 and 3000 nm, more preferably between 50 and 900 nm and even more preferably between 75 and 300 nm.
    [0055] In another preferred embodiment, the fibers of the additional intermediate layer (b ') have a morphology of fibers with a diameter greater than 500 nm.
    [0057] In another preferred embodiment, the fibers of the additional intermediate layer (b ') have a fiber morphology of diameter equal to that of the fibers of the intermediate layer (b).
    [0059] In another preferred embodiment, when the average fiber diameter of the intermediate layer (b) is less than 200 nm, the surface density of the intermediate layer is equal to or less than 0.5 g / m2.
    [0061] In another preferred embodiment of this invention, when the fibers of the polymers that make up the filter layers are smooth, the surface density of the intermediate layer is equal to or less than 1 g / m2.
    [0062] In another preferred embodiment of this invention, when the fibers of the polymers that make up the filter layers are pearled, the surface density of the intermediate layer is equal to or less than 3 g / m2.
    [0064] In the present invention, the surface density is expressed in g / m2; for each of the layers it is calculated by weighing a sample with known dimensions. This weight is then divided between the surface of the sample. This process is carried out with at least 5 samples from each layer in order to obtain an average surface density value for the entire layer.
    [0066] In another preferred embodiment, the surface density dispersion of the intermediate layer (b) is less than 30%, more preferably less than 20%, and even more preferably less than 10%.
    [0068] In the present invention, the polymers that make up the filter layers are preferably compostable and / or biodegradable in the environment.
    [0070] In another preferred embodiment, the multilayer filter of the present invention has levels of maximum resistance to inhalation respiration over areas of 55 cm2, with an air flow of 30 l / min less than 1.1 millibar, and with a flow of 85 l / min air less than 3.5 millibars.
    [0072] In another preferred embodiment, the multilayer filters of the present invention can be used alone, or stacked in any possible configuration, on themselves, or on other commercial multilayer or monolayer filters, to constitute new filters of greater thickness with greater filtration capacity.
    [0074] In the present invention, the term "polymer" refers to macromolecular materials both in the pure exreactor state, as additives and post-processed in commercial formulas typically used by the chemical industries, more commonly called plastic grades. Any of the polymers or grades plastics can be added in addition to process additives, promoters of biodegradability or that confer stability, other types of additives of the "filler" type, either in micro, submicro or nanometric form to improve their physicochemical or of antimicrobial retention and controlled release capacity. Such additives can be of the Chemicals type , fibers, sheets or particles.
    [0076] In the present invention, the terms referring to the morphology of "smooth" and "pearl" fibers refer to different types of morphology found in the generated fibrous structure. Thus, the term "smooth fibers" refers to when the fibers have a smooth surface with a rather regular section in terms of diameter. On the other hand, the term "pearl fibers" refers to fibers that have spherical, oblong beads or pearls or other irregular type, interspersed along the fiber section. This structure, being made up of thicker pearls, generates an additional micro porosity that makes them advantageous to improve the breathability (ease of the fabric for air to pass through its section) of the filter, although it reduces its resistance to the penetration of aerosols , for example, paraffin or sodium chloride, (ability of the tissue to reduce the passage of the virus through its section).
    [0078] On the other hand, the intermediate layers of the multilayer filters of the invention can be continuously manufactured by depositing each layer on the previous one, or manufactured separately and then optionally laminated, or by combining both.
    [0080] When lamination is done by calendering, this can be done using two or more rollers with or without pressure, in which at least one of them can be at the required temperature, or it can be the case that all the rollers are at required temperature.
    [0082] The calendering of the layers produced can be carried out in such a way that the inner layer is in contact with the roller that heats, or, conversely, that it is the last layer, which is in contact with the roller that is at the required temperature.
    [0084] In another preferred embodiment, the different layers can be continuously manufactured on top of the previous one and then carry out a treatment process with or without heat with or without pressure, preferably by calendering at low temperature, to ensure inter-layer adhesion, grant a smoother texture, and to reduce the thickness.
    [0086] As for the manufacture of the intermediate layers that make up the mask of the These are preferably carried out by any of the known electro-hydrodynamic and aero-hydrodynamic techniques for obtaining fibers, such as electrospinning, electrohydrodynamic direct writing, melt electrospinning, solution blow spinning, electrospraying, solution blow spraying, electrospraying assisted by pressurized gas or combination of all of the above. However, any other method of obtaining fibers may also be used, such as the centrifugal je t spinning or the combination between this and those previously mentioned. Electrohydrodynamic and aerohydrodynamic techniques are based on the formation of micro, submicro or ultrafine polymeric fibers at room temperature or lower, from a polymeric solution to which an electric field or gas pressure is applied. The fact that it is used in the form of a solution has great versatility, since it allows the incorporation of various substances (antimicrobials) in the solution itself. At the same time, the fact that its processability is at room temperature avoids certain problems such as the degradation of the active substances.
    [0088] With these techniques and the aforementioned polymers, the antimicrobial substance is incorporated into the present invention using techniques among which are without limitation: core-shell technology, co-deposition, direct mixing, emulsion techniques, pre-encapsulation in particles, or layer by layer deposition, etc.
    [0090] In the present invention, the layer-by-layer deposition method consists of the use of a system in which the layers are deposited sequentially within the same process. In this way, initially one of the layers is electro-stretched until the thickness is as desired and then the second layer is electro-stretched on top of the first, obtaining a continuous multilayer system in situ .
    [0092] A second aspect of the invention refers to obtaining the multilayer filters of the invention as defined above, which comprises the following steps:
    [0093] i) Deposition of the intermediate layer (b) on the inner layer (a);
    [0094] ii) Optionally, deposition of one or more additional intermediate layers (b ') on the intermediate layer (b);
    [0095] iii) Lamination of the outer layer (c) with the previous ones.
    [0096] A third aspect of the invention refers to obtaining the multilayer filters of the invention as defined above, which comprises the following steps:
    [0097] i) Deposition of the intermediate layer (b) on the inner layer (a);
    [0098] ii) Deposition of an additional intermediate layer (b ’) on the inner face of the outer layer (c);
    [0099] iii) Lamination of the previous layers so that the layers (b) and (b ’) are in contact.
    [0101] In a preferred embodiment of the invention, the different layers that make up the filter are laminated by simply joining the layers together, without any type of adhesion process.
    [0103] Optionally, the layers that make up the filter can be laminated partially or totally along its surface, using any known lamination technique, including calendering with or without pressure in hot or environmental conditions, by applying adhesives, with dots. fusion for example by ultrasound, or by heat sealing.
    [0105] Finally, a third aspect of the invention relates to the use of the multilayer filter of the present invention to manufacture, without limitation, medical respirators for patients who need assisted breathing, and to manufacture masks, washable or non-washable, of good protection. of the non-waterproof surgical type, or of the type FFP1, FFP2, N95 or FFP3 according to EN149 or of the type N95, or the like. The filters of the present invention can be served in bovines as an intermediate product to be later cut, by any industrial method, in the dimensions required by the final manufacturer of the product, or they can be cut into any shape or size, by any cutting method. For example, with laser or die cutter, with the appropriate dimensions and served as a final product. Therefore, they serve, without limitation, to manufacture disposable masks made of one or several pieces according to any known industrial method, or as a disposable, therefore, expendable filter for reusable masks.
    [0107] In a preferred embodiment, the multilayer filters of the present invention have a resistance to penetration of virus size particles less than 20%, more preferably less than 6%, and even more preferably less than 1%.
    [0109] In a preferred embodiment, the multilayer filters of the present invention have levels of maximum resistance to inhalation respiration over areas of 55 cm2, with an air flow of 30 l / min, less than 1.1 millibar, and with an air flow 85 l / min, less than 3.5 millibars.
    [0111] The multilayer filters of the invention have the first function, therefore, to protect against the penetration of microorganisms, typically against viruses and bacteria (both Gram-positive and Gram-negative), although preferably against viruses of sizes between 30-500 nm, such as , without limitation, adenovirus, coronavirus, human metapneumovirus, parainfluenza virus, influenza (influenza), respiratory syncytial virus (RSV), rhinovirus / enterovirus and more particularly, Ebola virus, herpes virus (HSV-1) , influenza virus (A, B, C, D), human respiratory syncytial virus (RSV), chicken pox SARS-CoV and its derivatives, as well as against SARS Covid-19.
    [0113] Throughout the description and the claims, the word "comprises" and its variants are not intended to exclude other technical characteristics, additives, components or steps. For those skilled in the art, other objects, advantages and characteristics of the invention will emerge in part from the description and in part from the practice of the invention. The following examples and figures are provided by way of illustration, and are not intended to be limiting of the present invention.
    [0115] BRIEF DESCRIPTION OF THE FIGURES
    [0117] Fig. 1. Scheme of the tri-layer structure with smooth ultra-fine PVDF fibers.
    [0118] Fig. 2 . Scheme of the tri-layer structure with pearlized ultra-fine PVDF fibers.
    [0119] Fig. 3 . Schematic of the tri-layer structure with smooth ultra-fine PHBV fibers.
    [0120] Fig. 4 . Structure of the multilayer structure of sequentially stretched and symmetric sandwich electrowinned PVDF.
    [0121] Fig. 5 . Diagram of the co-deposition of ultra-fine fibers of PVDF and PAN electrostimated in situ.
    [0122] Fig. 6 . Scheme of the tri-layer structure with smooth PHBV microfibers.
    [0123] EXAMPLES
    [0125] Next, the invention will be illustrated by means of examples made by the inventors, for each of the types of filters developed (FFP3 passive filter, design with antimicrobial capacity and biodegradable design) that demonstrate the effectiveness of the product of the invention.
    [0127] Example 1: FPP3 tri-layer structure system with electrospun PVDF with smooth ultra-fine fiber structure
    [0129] The core layer of electrospun ultrathin fibers was made of polyvinylidene fluoride with a molecular weight of 300 kDalton. For this, a 15% by weight (wt.%) PVDF solution was started in a DMF / Acetone (50:50 wt.) Mixture. Once dissolved, the fiber sheet was manufactured using the technique electrospinning or electrostretching. For this, an emitter voltage of 18kV and a linear multi-emitter injector voltage were used. These ultrafine fibers were deposited on a rotary collector at a speed of 200 revolutions per minute (rpm) on a 30 g / m2 polypropylene (PP) substrate and at a distance of 20 cm. Said manufacture was carried out at a temperature of 30 ° C and a relative humidity of 30%. This layer has a surface density of 1 g / m2. After production, a 30 g / m2 PP layer was placed on the PVDF deposition and calendered at 80oC so that the final material remains as the multilayer filter described in Figure 1.
    [0131]
    [0134] The PVDF layer generated by the electrospray technique was observed with a transmission electron microscope (SEM), resulting in a microstructure of fibers of constant diameter between 220 and 280 nm, as can be seen in Figure 1. When this material is Subsequently undergoes a washing cycle with stirring in hot water at 60oC and detergent and dries, the consistency and morphology of the layer intermediate measured by SEM is not affected.
    [0136] Tests of resistance to penetration with paraffin aerosol according to standard 149: 2001 + a1: 2009 (point 8.11) gave a value of 0.9%, therefore, this filter would be classified as type FFP3 (out of every 100 aerosol particles , 1 or less than 1 pass).
    [0138] Example 2: FFP1 tri-layer structure system with electrospun PVDF with pearlized ultrafine fiber structure
    [0140] The core layer was made of polyvinylidene fluoride with a molecular weight of 500 kDalton. For this, a 10% by weight (wt.%) PVDF solution was started in a DMF / Acetone (50:50 wt.) Mixture. Once dissolved, the fiber sheet was manufactured using the electrostretching. For this, an emitter voltage of 19kV and a collector voltage of -7kV were used. A flow rate of 10ml / h was also used, through a linear multi-emitter injector. The fibers were deposited on a rotary collector at 200 rpm covered by a 30 g / m2 non-woven PP substrate and at a distance of 20 cm. Said manufacture was carried out at a temperature of 30 ° C and a relative humidity of 30%. This layer has a surface density of 3 g / m2. After production, a layer of PP 30 g / m2 was placed on the PVDF deposition and calendered at 80oC so that the final material remains as the multilayer filter illustrated in Figure 2.
    [0142]
    [0145] The electrostream-generated PVDF layer was observed with a transmission electron microscope (SEM), resulting in a fiber structure of around 200 nanometers with micrometer-sized pearl structures, which refer to areas of the fibers in which their size increases considerably forming a kind of particles, thus calling them pearl fibers. This pearl morphology gives advantages in the breathing capacity of the tissue since the pearls or beads help Optimizing the packing density of the fiber and its presence increases the distance between the fibers to reduce the pressure drop in the filters.
    [0147] Tests of resistance to penetration with paraffin oil according to standard 149: 2001 + a1: 2009 (point 8.11) gave a value of 17.8%, therefore, this filter would be classified as type FFP1 (out of every 100 aerosol particles , 20 or less than 20 passes).
    [0149] Example 3: FFP2 tri-layer structure system with smooth ultrathin electrospun fibers of PAN and Zinc Oxide
    [0151] The central layer was made of Polyacrylonitrile (PAN). For this, an 11% by weight (wt.%) Solution of PAN was used with dimethylformamide (DMF) and Zinc oxide nanoparticles (ZnO) in a percentage of 2 by weight (wt.%), To generate antimicrobial properties . Once dissolved, the fiber sheet was manufactured using the electrospray technique. For this, an emitter voltage of 30kV and a collector voltage of -10kV were used, a flow rate of 5 ml / h was also used, through a linear multi-emitter injector. The fibers were deposited on a rotary collector at a speed of 200 rpm covered by a 30 g / m2 non-woven PP substrate and at a distance of 20 cm. Said manufacture was carried out at a temperature of 30 ° C and a relative humidity of 30%. This layer has a surface density of 0.5 g / m2. After production, a layer of 30 g / m2 non-woven PP was placed over the PAN deposition and calendered at 80oC so that the final material is similar to the multilayer filter described in Figure 1.
    [0153]
    [0156] Likewise, the antimicrobial properties of this structure were evaluated using a modification of the Japanese Industrial Standard JIS Z2801 (ISO 22196: 2007) against the strains of Staphylococcus aureus ( S. aureus) CECT240 (ATCC 6538p) and Escherichia coli ( E. coli) CECT434 (ATCC 25922). The filters were analyzed in terms of the growth inhibition capacity of these populations in the material and it was seen, as illustrated in Table 1, that the filters showed a strong growth inhibition of both strains (R> 3) with a reduction of 3 registration units with respect to the control (filters without ZnO), the first day of your measurement. These results indicate that these filters efficiently inhibit this type of strain, since an R <0.5 would indicate that the inhibition of the material towards bacteria is not significant, while an R> 1 and <3 would indicate that it is slightly significant. An R> 3 would indicate that it is clearly significant, which means that the inhibition of the growth of microorganisms is effective and constant over time.
    [0158] Table 1 . Reduction of S. aureus and E. coli in the filters with antimicrobial capacity for 15 days
    [0160]
    [0163] Tests of resistance to penetration with paraffin oil according to standard 149: 2001 + a1: 2009 (point 8.11) gave a value of 5%, therefore, this filter would be classified as type FFP2 (of every 100 aerosol particles, 6 or less than 6 pass).
    [0165] Example 5: Tri-layer structure system FFP2 with electro-stretched PHBV with structure of smooth ultra-fine fibers
    [0167] The core layer was made of Poly (3-hydroxybutyrate-co-3-hydroxyvalerate) (PHBV) supplied by Ocenic Resins SL, Valencia. For this, a 2% by weight (wt.%) Solution of PHBV in trifluoroethanol (TFE) was started. Once dissolved, it was manufactured with and without the addition of BrLi (0.2 wt%) and the fiber sheet was manufactured using the electrospinning or electrospray technique. For this, an emitter voltage was used of 18kV and a collector voltage of -8kV, a flow rate of 20 ml / h was also used, through a linear multi-emitter injector. The fibers were deposited on a rotary collector at a speed of 200 rpm covered with a 30 g / m2 biodegradable non-woven cellulose spunlace substrate and at a distance of 20 cm. Said manufacture was carried out at a temperature of 30 ° C and a relative humidity of 30%. This layer has a surface density of 1 g / m2. After production, a layer of 30 g / m2 non-woven cellulose biodegradable spunlace was placed over the PHBV deposition and calendered at 80 ° C so that the final material remains as the multilayer filter described in Figure 3.
    [0169]
    [0172] The electrospray-generated PHBV layer was observed with a transmission electron microscope, resulting in a microstructure of fibers with a constant diameter of between 200 and 300 nm approx. as you can see in Figure 4.
    [0174] Bio-disintegration tests were carried out in accordance with ISO 20200 "Plastics - Determination of the degree of disintegration of plastic materials under simulated composting conditions in a laboratory-scale test". The PHBV filter could be considered fully compostable according to ISO 20200 since the PHBV disintegration process reached a total disintegration after 20 days of testing This short degradation time is probably related to the low filter thickness, necessary for a good respiration.
    [0176] Tests of resistance to penetration with paraffin oil according to standard 149: 2001 + a1: 2009 (point 8.11) gave a value of 5.5%, therefore, this filter would be classified as type FFP2 (out of every 100 aerosol particles , 6 or less than 6 pass).
    [0177] Example 6: FFP3 multilayer structure system with sequentially stretched electrowinned PVDF arranged in symmetrical sandwich mode
    [0179] The core layer was made of 13% by weight polyvinylidene fluoride (PVDF, molecular weight 300 kDalton) in DMF / Acetone (50:50 wt.). Once the solution was dissolved, the fiber sheet was manufactured using the electrospray technique. For this, a transmitter voltage of 25kV was used as well as a collector voltage of -10kV. A flow rate of 10 ml / h through a linear multi-emitter injector was also used. The fibers were deposited on a rotary collector (200 rpm) covered by a 30 g / m2 non-woven PP substrate and at a distance of 20 cm. Said manufacture was carried out at a temperature of 30 ° C and a relative humidity of 30%. This layer has a surface density of 1 g / m2.
    [0181] This same layer was prepared in duplicate under the same conditions, but at 0.5 g / m2 on a layer of non-woven PP of 30 g / m2 and was symmetrically folded, so that the structure would be as reflected in Figure 4. This structure improves the filtration behavior because it fixes the fibers in the substrate and the entire filter is adhered by interaction between the nanofibers.
    [0183] The layers of PVDF generated by electrostretching were observed with a transmission electron microscope where a constant diameter of between 200 and 300 nm was obtained. When this material was subsequently subjected to a wash cycle with stirring in hot water at 60oC and detergent and dried, the consistency and morphology of the intermediate layer measured by SEM is not affected.
    [0185] Tests of resistance to penetration with paraffin oil according to standard 149: 2001 + a1: 2009 (point 8.11) gave a value for the single layer fiber structure of 1 g / m2 of 2.3% (type FFP2), while the symmetrical sandwich double layer structure gave 0.9%. Therefore, this last filter would be classified as FFP3 type (out of every 100 aerosol particles, 1 or less than 1 passes).
    [0187] Resistance to inhalation respiration was measured according to EN149: 2001 + a1: 2009 (point 8.9) over an area of approx. 53 cm2 in a Sheffield, constant breathing test head and digital flow meter. Breathing results were for the monolayer of 0.7 millibars for an air flow of 30 l / min; and for the 0.8 millibars double layer structure, within the limits of the FFP3 certification. Inhalation breathing tests carried out at 85 l / min as recommended by the N95 certification, gave values for the double layer structure of 3.3, within the limits of the N95.
    [0189] Example 7: FFP3 tri-layer framework system with multiple co-deposited electrospun layers
    [0191] The central layer was made of polyvinylidene fluoride (PVDF, 300 kDalton molecular weight) and polyacrylonitrile (PAN) to obtain a filter with different fiber diameters. For this, a 13 % by weight (wt.%) PVDF solution was started in DMF / Acetone (50:50 wt.) And an 11% (wt.%) By weight PAN solution in DMF. Once both solutions were dissolved, the fiber sheet was manufactured using the co-deposition electrostretching technique, where both types of fibers are simultaneously electrowinded by two linear multi-emitter injectors. For this, an emitter voltage of 18kV and 25 kV was used for the dissolution of PVDF and PAN, respectively, as well as a collector voltage of -30kV. A flow rate of 13.8 ml / for the PVDF and 3 ml / h for the PAN was also used through 2 linear multi-emitter injectors located in parallel. The fibers were deposited on a rotary collector (200 rpm) covered by a 30 g / m2 non-woven PP substrate and at a distance of 20 cm. Said manufacture was carried out at a temperature of 30 ° C and a relative humidity of 30%. This layer has a surface density of 1.2 g / m2.
    [0193] After production, a layer of 30 g / m2 nonwoven PP was placed over the PAN deposition and calendered at 80oC so that the final material remains as the multilayer filter illustrated in Figure 5.
    [0195]
    [0198] The electrospray-generated PVDF and PAN layer was observed with a transmission electron microscope where a constant diameter of between 150 and 250 was obtained approx nm for PAN fibers and a diameter of between 300-500 nm for PVDF fibers.
    [0200] Tests of resistance to penetration with paraffin oil according to standard 149: 2001 + a1: 2009 (point 8.11) gave a value for the structure of 1.2 g / m2 gave 0.6%. Therefore, this last filter would be classified as FFP3 type (out of every 100 aerosol particles, 1 or less than 1 passes).
    [0202] Example 8: Electro-stretched tri-layer structure system with micrometer fibers
    [0204] The core layer was made of Poly (3-hydroxybutyrate-co-3-hydroxyvalerate) (PHBV) supplied by Ocenic Resins SL, Valencia. For this, a 6 % by weight solution of PHBV in trifluoroethanol (TFE) was started. Once dissolved, the fiber sheet was manufactured using the electrospray technique. For this, an emitter voltage of 15kV and a collector voltage of -8kV were used, a flow rate of 20 ml / h was also used, through a multi-emitter injector. The fibers were deposited on a rotary collector at a speed of 200 rpm covered with a 30 g / m2 biodegradable non-woven cellulose spunlace substrate and at a distance of 20 cm. Said manufacture was carried out at a temperature of 30 ° C and a relative humidity of 30%. This layer has a surface density of 0.5 g / m2. After production, a layer of 30 g / m2 non-woven cellulose spunlace was placed on top of the PHBV deposition.
    [0206] The electrospray-generated PHBV layer was observed with a transmission electron microscope, resulting in a microstructure of fibers with a constant diameter of 900-1200 nm, as can be seen in Figure 6.
    [0208] Tests of resistance to penetration with paraffin oil according to standard 149: 2001 + a1: 2009 (point 8.11) gave a value for the monolayer structure of 0.5 g / m2 of 87%, corroborating the need to obtain fibers of Ultra-thin size for this particular application.
    权利要求:
    Claims (29)
    [1]
    1. A multilayer filter characterized by comprising at least:
    i) An internal layer (a) that is in contact with the user's skin, characterized in that it is composed of filtering polymeric materials, and that has a surface density of at least 0.01 g / m2, more preferably between 5 and 3000 g / m2, even more preferably between 20 and 300 g / m2;
    ii) An intermediate layer (b) characterized in that it is composed of polymeric fibers, which optionally contains antimicrobial substances, and which have a surface density of at least 0.01 g / m2, more preferably between 0.1 and 10 g / m2; and even more preferably between 0.2 and 3 g / m2;
    iii) an outer layer (c) characterized in that it is composed of filtering polymeric materials, and that it has a surface density of at least 0.01 g / m2, more preferably between 5 and 3000 g / m2; and even more preferably between 20 and 300 g / m2.
    [2]
    2. Filter according to the preceding claim, wherein the polymeric material that makes up the inner layer (a) and the outer layer (c) are independently selected from among polypropylene, polyamide, polyester, natural fibers, cotton, and cellulose, or any of their combinations.
    [3]
    3. Filter according to any of the preceding claims, wherein the constituent fibers of the intermediate layer (b) are selected from polyvinylidene polychloride, polyacrylonitrile, and polyhydroxyalkanoates, or any combination thereof.
    [4]
    4. Filter according to the preceding claim, wherein the constituent fibers of the intermediate layer (b) are polyhydroxyalkanoates.
    [5]
    5. Filter according to any of the preceding claims, wherein the constituent fibers of the intermediate layer (b) have a molecular weight of less than 200 kDalton.
    [6]
    6. Filter according to any of the preceding claims, wherein the intermediate layer (b) contains an antimicrobial substance selected from among zinc oxide, silver, silver nitrate, copper, copper oxide, graphene, carbon microtubes, carbon nanotubes, titanium oxide, titanium dioxide, natural extracts, essential oils, chitin, chitosan, aluminum oxide, silicon dioxide, cyclodextrins, antibiotics, tetracycline, iodine, triclosan, chlorhexidine, acyclovir, and cycloofloxacin, or combinations thereof.
    [7]
    7. Filter according to the preceding claim, wherein the antimicrobial substance is zinc oxide or zinc oxide nanoparticles.
    [8]
    8. Filter according to any of the preceding claims, wherein the fibers of the intermediate layer (b) are fibers of smooth or pearl morphology.
    [9]
    9. Filter according to any of the preceding claims, wherein the intermediate layer (b) comprises an additional layer (b '), characterized in that it is composed of the same polymeric fibers as the first intermediate layer (b) on which it is deposited .
    [10]
    10. Filter according to any of claims 1 to 8, wherein the intermediate layer (b) comprises an additional layer (b '), characterized in that it is composed of polymeric fibers different from those of the first intermediate layer (b) on which deposit.
    [11]
    11. Filter according to any of claims 9 to 10, where the morphology of the polymeric fibers that make up the intermediate layers (b) and (b ') is the same.
    [12]
    12. Filter according to any of claims 9 to 10, where the morphology of the polymeric fibers that make up the intermediate layers (b) and (b ') is different.
    [13]
    13. Filter according to claim 11 where the surface density of the intermediate layers (b) and (b ') is the same.
    [14]
    14. Filter according to claim 11 where the surface density of the intermediate layers (b) and (b ’) is different.
    [15]
    15. Filter according to claim 12 where the surface density of the intermediate layers (b) and (b ') is the same.
    [16]
    16. Filter according to claim 12 where the surface density of the layers intermediates (b) and (b ') is different.
    [17]
    17. Filter according to any of claims 9 to 16, wherein the fibers of the additional intermediate layer (b ') have a morphology of fibers with a diameter greater than 500 nm.
    [18]
    18. Filter according to any of the preceding claims, wherein the dispersion of the surface density of the intermediate layer (b) is less than 10%.
    [19]
    19. Filter according to any of the preceding claims, wherein the polymers that make up the filter layers are preferably compostable and / or biodegradable in the environment.
    [20]
    20. Filter according to any of the preceding claims, where the multilayer filters of the present invention have levels of maximum resistance to inhalation respiration over 55 cm2 areas, with an air flow of 30 l / min less than 1.1 millibar , and with an air flow of 85 l / min less than 3.5 millibars.
    [21]
    21. Filter according to any of the preceding claims, wherein said filter can be stacked in any possible configuration on themselves or on other commercial multilayer or monolayer filters.
    [22]
    22. Procedure for obtaining a mask according to any of claims 1 to 21, comprising the following steps:
    i) Deposition of the intermediate layer (b) on the inner layer (a);
    ii) Optionally, deposition of one or more additional intermediate layers (b ’) on the intermediate layer (b);
    iii) Lamination of the outer layer (c) with the previous ones.
    [23]
    23. Procedure for obtaining a mask according to any of claims 1 to 21, comprising the following steps:
    i) Deposition of the intermediate layer (b) on the inner layer (a);
    ii) Deposition of the additional intermediate layer (b ') on the inner face of the outer layer (c);
    iii) Lamination of the previous layers so that layers (b) and (b ’) are in contact.
    [24]
    24. Method according to any of claims 22 and 23, where the layers (a), (b), (b ') and (c) are laminated by simply joining the layers together, without any type of adhesion process.
    [25]
    25. Process according to any of claims 22 and 23, where the layers (a), (b), (b ') and (c) are partially or totally laminated along its surface by means of procedures selected from calendering with pressure, calendering without pressure, application of adhesives, with ultrasound melting points, and heat sealing.
    [26]
    26. Filter according to any of claims 1 to 21 for use in the manufacture of respirators for medical use and masks, washable or non-washable, for protection.
    [27]
    27. Mask containing the filter according to any of claims 1 to 21 wherein the mask is protective against microorganisms.
    [28]
    28. Mask according to the preceding claim, wherein the microorganism is a virus.
    [29]
    29. Mask according to the preceding claim, wherein the virus is selected from Ebola virus, herpes virus, influenza virus, human respiratory syncytial virus, chickenpox, SARS-CoV and SARS Covid-19.
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    同族专利:
    公开号 | 公开日
    ES2765374B2|2021-03-30|
    WO2021005258A3|2021-04-15|
    WO2021005258A2|2021-01-14|
    引用文献:
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    ES202030319A|ES2765374B2|2020-04-20|2020-04-20|MULTILAYER FILTER WITH ANTIMICROBIAL PROPERTIES AND ITS USE IN RESPIRATOR AND PROTECTIVE MASK APPLICATIONS|ES202030319A| ES2765374B2|2020-04-20|2020-04-20|MULTILAYER FILTER WITH ANTIMICROBIAL PROPERTIES AND ITS USE IN RESPIRATOR AND PROTECTIVE MASK APPLICATIONS|
    PCT/ES2020/070645| WO2021005258A2|2020-04-20|2020-10-23|Multilayer filter with antimicrobial properties and use thereof in industrial filtration applications and protective face masks|
    US17/235,467| US20210322907A1|2020-04-20|2021-04-20|Multilayer filter with antimicrobial properties and use thereof in industrial filtration applications and protective masks|
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