MXPA00012590A - Structured surface filtration media - Google Patents

Abstract

A filtration media having at least one structured polymeric layer, wherein a structured surface is defined within the layer. Layers may be configured as a stack that has the structured surfaces defining a plurality of ordered inlets open through a face of the stack and corresponding ordered fluid pathways, thereby forming an ordered, porous volume. The ordered fluid pathways may be defined by a plurality of flow channels formed within the structured surfaces of the structured layers, or may be defined by a plurality of protuberances formed in an ordered pattern within the structured surfaces of the structured layers.

Description

FILTRATION MEANS WITH STRUCTURED SURFACE FIELD OF THE INVENTION The present invention is concerned with means and filtering device comprising at least one layer having a structured surface defining highly ordered trajectories for the fluid.

BACKGROUND OF THE INVENTION An important segment of the development of filtration media and filtration devices for separating particles from a fluid stream has been in the area of non-woven fiber technology. From the use of fabrics derived from meltblown microfibers to that of microdenier staple fibers, the tendency has been to decrease the fiber size in order to increase the available surface area per unit volume of fabric. These nonwovens are generally low density fabrics, glued together by entanglement, based on polymers, which incorporate fibers of microscopic or almost microscopic size. The main mechanisms that control the separation of particles from a fluid stream by means of a fibrous filter with direct interception, inertial impact, diffusion and electrostatic attraction. Particle collection by interception occurs when a particle following a gas stream line collides and is captured Ref: 125698 for the filtering surface. The inertial impact results when the particles deviate from the fluid stream to collide with the fibers. The particles impacted in both cases adhere to the fibers by forces such as Van der Walls forces. Diffusional collection occurs when Brownian movement of very small particles improves the likelihood of its contact with the filtration surface. This movement causes the particles to deviate from the fluid stream lines and accumulate on the individual filter fibers. Electrostatic collection is an important mechanism by which charged particles are attracted to collection surfaces charged oppositely by coulombic attraction. Fibrous filters for fluids, especially gas filters, usually combine all four capture mechanisms. Non-woven filters incorporate the advantages of these fibrous filters due to their inherent properties. However, limitations also arise with nonwovens as filtering means of their inherent properties. Non-woven fabrics by definition are randomly formed structures that have limited geometrical order. The limited order is caused by the variability between individual fibers and the degree of fiber to fiber conformation within the fabric. This order ^ j-gg ^^^^^^^^^^^^ g ^^ g ^^^^^^^^ limited is manifested by gross irregularities caused by the formation of macrostructures known as shingle and fiber nests. The fabric macrostructures have local concentrations of fibers that cause variation of the pore size, also as a variation of the mass through the fabrics. As a result, relatively large openings between the fibers allow particles to pass that would have been excluded and the small openings fill and become ineffective. In the design of the filter media these limitations are moderated by the use of additional material at the cost of higher flow resistance through the filter. These effects can be complicated during use in filtration applications by the force of the applied fluid, which can alter the structure of the fabric and thus the efficiency of the filtering device. In addition, the pressure load of the fabric, wherein the fabric is formed mechanically in a product, for example, a folded structure, can also cause additional deformation of the fibers and fabric, resulting in a decrease in the efficiency of the fabric. filtration. Other limitations of non-woven fabrics of high surface area as filter media occur when the filter employs thin flat layers of non-woven fabric, such as in respirators or the filter employs folded layers in a more three-dimensional arrangement, such as in room filters, ^^^ 1A ^ > ^. ... ^^ -. ^ «^^^ - ^^^ - ^ .. > J- .. - ^^ ^^^. ^ Mu ^^^ f áÉOíám? ^^ íáÉk ^ í ^^^^^^^ É ^ furnaces or computer. Due to their respective uses, the velocity of the fluid through the face of the respirator type filters tends to be lower, while the velocity of the fluid through the face of the circulating air filters, that is the room filters , oven or computer, tends to be higher. However, in both situations, the nonwoven fabric material commonly functions as a surface charge filter, inevitably resulting in a surface seal. In the surface seal, the first layers of filter material are filled and sealed with particulate matter separated from the fluid stream. Consequently, the filters are not effectively using the larger portion of the filter mass and thus the performance of the filter is limited based on the surface area of the filter instead of the filter volume. The use of multiple layers to increase the efficiency of the filter, especially in respirator type filters, can cause an increase in the resistance to flow through the media as the fluid passes through the filter layers. The resistance to flow is a function of the surface velocity of the gas and the ratio of the size, orientation and number of tortuous channels through the filter. In general, a filtration medium with a more evenly distributed surface area will obtain a higher overall filtration efficiency allowing the use of -. ^ - ^. «.. TL ^ - * ....." »....., .., ^ -.-..- Ma ^^ É ^ ¿¡^ ^ ^ ^ - Less material and, in turn, reduces resistance to flow through the media. Resistance to flow through filtration media is a general design restriction for any filtering device. Flow resistance is particularly problematic in lower surface velocity applications because the fluid velocity is low even before filtration and any resistance to flow within the filter will have a dramatic effect on its performance. This resistance to flow can cause problems with the overall fluid handling system in which the filter is used. Folding structures of smaller fiber non-woven fabrics are frequently used in higher surface velocity applications to reduce flow resistance and improve service life. This is because there is more filtering surface in a given volume, thereby increasing the percentage of surface openings per filter box area. When the non-woven fabric is composed of microfibers, however, the folded structures can sometimes reduce the fluffiness (see U.S. Patent No. 5,656,368 issued to Braun et al) and may be limited by the size of the microfibers used because it is more likely that smaller fibers cause surface sealing. Larger fibers can cause the filter to suffer from reduced overall filtration capacity due to a decrease in the actual fiber surface area. Other means for improving the efficiency of the filter is by treating the filter fibers to make them more attractive to the particles or the like to be separated from a fluid stream. The treatment methods include both passive and active electrostatic charge of the fibers, application of sticky material to the fibers, application of chemical additives such as catalysts or other reactive agents, as well as application of other types of additives, in which are included deodorants, drying agents, disinfectants, fragrances and agents that eliminate ozone. Although treatment methods can improve particle capture by fibers, filters are still subject to deficiencies associated with randomized media, such as surface obturation and flow resistance limitations discussed above. Examples of treated filtration media include commercial filter products known as electretes, such as those available from 3M Company under the trade designation "Fíltrete". Other types of filter media available for removal of particles from a fluid stream include woven and knitted materials. These types of materials tend to have a more orderly structure, making them less susceptible to the limitations inherent in nonwovens. However, these materials have their own problems with the control of the fidelity of the structures due to the variability in the constituent fiber material, fiber formation and fabric construction. In addition, other problems include limitations such as sufficiently small pore formation, costs of the constituent material and manufacturing costs.

BRIEF DESCRIPTION OF THE INVENTION The present invention overcomes the disadvantages and deficiencies of the prior art by providing means of. Filtration or filtration device that is efficient, is suitable for a deep bed load, operates at a low flow resistance and has a high collection capacity. More specifically, the present invention provides filtration means comprising at least one layer having a structured surface defining highly ordered fluid paths. Preferably, the filtration means of the present invention comprises a stack of layers having structured surfaces that define a highly ordered arrangement of filter openings and paths for the fluid through the filtration means.

The structured surfaces of the layers may comprise features that define channels that form the trajectories for the fluid or may comprise features such as discrete protrusions that form the trajectories for the fluid. The filter openings defined by the layers of stacked structures remove the particles by exclusion. The removal without exclusion of the particles is facilitated by the surface area of the structured surface characteristics. The filtration means according to the present invention have the advantage of being efficient and having a high capacity because they use full volume to function as a deep bed filter rather than as a surface filter. It is easily and economically manufactured from a variety of materials that include flexible or rigid non-expensive polymers. The structured surface characteristics of the filtration media are highly controllable, predictable and ordered and are formable with high reliability and repeatability using microreplication techniques or other techniques. The filtration media can be produced in a variety of configurations to meet the filtration requirements of a given application. This variety is manifested in: possibilities of structured surface characteristic - discrete channels, open channels or -.to.a.i ^ h ^ aB-a protuberances; channel configurations - wide, narrow, in the form of "V" and / or subchannels; stack configurations - glued or unbonded, surface layers, non-surface layers, aggregate layers, aligned channels, displaced channels and / or channel configurations and filter openings - pore size, pore configuration or pore geometry. In addition, the layers can be treated for improved filtration or other purposes. The advantages mentioned above are obtained by means of a filtration means formed from at least one polymeric layer having a structured surface defined therein. The layers can be configured as a stack with the structured surfaces of the layers defining a plurality of ordered entries open through one side of the stack and corresponding orderly fluid paths or may consist of a single layer with a structured surface having a cover layer or may consist of a capless layer having a structured surface. In a stacked or covered arrangement, the layers thus form a porous ordered volume. The ordered fluid paths of the filter media can be defined by a plurality of flow channels formed within the structured surfaces. The plurality of flow channels is defined as preference through a series of peaks, each has two aA ^ a. »...- alt ^ - 'tf.- | -f. [- f | ", | side walls The peaks can be separated by a flat floor or by sub-planes that form sub-channels within the channels The peaks may have heads that overlap adjacent flow channels. The flow channels of a layer having a structured surface may all be the same or different. Each layer of the filter media may have the same flow channel configuration or may be different. The flow channels on adjacent layers may be aligned or displaced. Pairs of layers of the filtration means may be facing each other and the facing layers together may be coupled together. The layers may have structured surfaces defined on both sides. Additional layers can be added to the stack. A layer cap can cover a portion of the upper part of the layer and additional layers can be placed between adjacent layers of the pile. The layers of the pile, or a layer and a layer cover can be glued together. The layers can be formed from the same or different polymeric materials. The filtration media can be treated to improve the removal of particles or to provide other benefits such as providing oil and water repellency, eliminating odors, eliminating organic matter, eliminating ozone, disinfecting, drying and introducing fragrances. The treatment may include loading the layers ^., - "- - .. AI-. -Ji ..... -..- ^ - ^ - - ^ .- ^^ A ^ sSaia-¡M «s ^ 3k ^ _. J_ A ^ ttJ ^ J ^ J ^, ¿^^ = ^^ ^ jfa, to form an electret, surface coating of the layers or addition of treated layers. The above-mentioned advantages can also be obtained by a filtration method using the filtration means of the present invention. This method includes providing the filtering means, positioning the filtration means in a fluid flow path, passing a fluid through the filtration means and separating the fluid particles in the filtration means. This method may further comprise cutting a portion of a stack of layers having structured surfaces to a specific thickness for use as the filtering means, treating a portion of the layers to provide filtering benefits and directing the flow to a specific destination when configuring the trajectories for the fluid arranged within the filtering means. In addition, these advantages can be obtained by a method of making and using the filtration means of the present invention. This method provides at least one layer having a structured surface that defines highly ordered trajectories for the fluid. The method can provide a plurality of layers having structured surfaces that define highly ordered fluid paths when stacking the plurality of layers with the structured surfaces to define a plurality of open ordered openings across a side of the stack and trajectories for the Correspondingly arranged fluid and which form an ordered pore volume by this. The method also includes positioning the ordered porous volume in a path for fluid flow, passing the fluid through the ordered pore volume and separating the particles from the fluid in the ordered pore volume. This method can also comprise gluing a portion of the layers, cutting a portion of the layers into specific thicknesses, treating a portion of the layers to provide filtering benefits and directing the flow of fluid to a specific destination when configuring the trajectories for the fluid. ordered within the filtering media.

BRIEF DESCRIPTION OF THE DRAWINGS Figure 1 is a perspective view of a stack of layers having structured surfaces forming a filtration medium according to the present invention; Figure 2 is an end view of a stack of layers having structured surfaces forming the filtering means of Figure 1; Figure 3 is a perspective view of the filtration means formed from layers having structured surfaces; Figure 4 is an enlargement of a portion of the filtration means shown in Figure 3; Figure 5 is an end view of stacked layers having structured surfaces, illustrating an alternative layer configuration that can be used by the filtration means according to the present invention; Figure 6 is an end view of stacked layers having structured surfaces, illustrating another alternative layer configuration that can be used by filtering means in accordance with the present invention; Figure 7 is an end view of a layer having a structured surface illustrating a particular channel configuration that can be used by filtering means in accordance with the present invention; Figure 8 is an end view of a layer having a structured surface illustrating another channel configuration that can be used by filtering means in accordance with the present invention; Figure 9 is an end view of a layer having a structured surface that still illustrates ^^^ ^ ^ ^^^^^^^ another channel configuration that can be used by filtering means in accordance with the present invention; Figure 10 is an end view of a stack of layers having structured surfaces, wherein the facing layers are coupled together by means of channels with heads; Figure 11 is an end view of a stack of layers having structured surfaces with additional layers interposed between the front layers and the non-facing layers; Fig. 12 is a perspective view of a portion of a layer having a structured surface having discrete, head protrusions formed in an ordered arrangement; and Fig. 13 is a front view of a respirator face mask utilizing filtration means. according to the present invention.

DETAILED DESCRIPTION OF PREFERRED MODALITIES With reference to the attached figures, the similar components are denominated with similar numbers in all the various figures. Figures 1-4 illustrate filtration means 10 including layers 12. Each layer 12 has a structured surface 13 over so ^ ¿^^^^.-.... "-. minus one of its two main surfaces, where one. structured surface 13 comprises a surface with a topography (the surface characteristics of an object, place or region thereof). In this embodiment, the structured surfaces 13 comprise a plurality of channels 25 formed within the layers 12 preferably as shown, in a consistent, orderly manner. These channels 25 are defined by a series of peaks 28 formed of side walls 26 with or without a flat floor 30 therebetween. Together the stacked layers 12 form a porous, highly ordered, three dimensional filtration media, wherein fluid, such as air, can flow through the media 10 via ordered fluid paths, as defined by the channels 25, in such a way that particles or other matter can be separated from the fluid by exclusion and / or adhesion to the structured surfaces. Ordered means that the trajectories defined through the media are predetermined. As exemplified hereinafter, each path need not be the same as another of the same layer or a different layer. However, each path is predetermined in the sense that each path is established by a predetermined design of the structured surface 13 of each layer 12. A porous medium is one that only allows the flow of the fluid through the means by means of more than one flow path. Figures 3 and 4 are electron micrograph illustrations of one embodiment of the filtration means 10 according to the present invention which define a highly ordered arrangement of channels composed of many layers 12. Each of the layers 12 may comprise a material semi-rigid or rigid, flexible, similar or different, which may be chosen depending on the particular application of the filtration means 10. Preferably, each of the layers 12 comprises a polymeric material because such material is normally less expensive and due to which such a polymeric material can be formed with exactly a structure surface 13. The use of a polymeric film 12 in the form of for example a film layer can provide a structured surface defining a large number of - and high density - channels for the flow of fluid 25 on a major surface thereof. Thus, highly ordered porous filtration means can be provided by being manufactured with a high level of accuracy and economy. As shown in Figures 1-4, these filtration means 10 are formed by stacking the layers 12 one on top of the other. In this way, any number of layers 12 can be stacked together to form a -.-....- ^^ A ^ .1 ^ ... ^^ - - ^ - - ^ - .. a ^, aa.aiMfati filtration medium 10 that has the appropriate height and porous area designed specifically based on the particular application. One advantage of direct stacking of the layers 12 on top of each other is that the second main surface 11 of each layer 12 provides a cover over the channels 25 of the lower adjacent layer 12. Accordingly, each channel 25 can be converted into a discrete path for fluid flow through the filtration means 10. A layer 12 can be glued to the peaks 28 of some or all of the structured surface 13 of an adjacent layer to improve the creation of discrete trajectories of the channels 25. This can be done using conventional adhesives that are compatible with the materials of the layers 12 or can be made using adhesion or thermal bonding, ultrasonic gluing, mechanical devices or the like. Joints can be provided completely along the peaks 28 to the adjacent surface 11 or point junctions can be provided according to an ordered or random configuration. Alternatively, the layers 12 can simply be stacked one on top of the other, whereby the structural integrity of the stack appropriately improves the creation of discrete flow channels 25. To close some, but preferably all of the channels 25 of the top layer 12, a lid layer 20 can also be provided, as shown in Figure 1. This lid layer 20 can be glued or non-glued in the same manner or in a different manner as the inter-layer bonding described above. The material for the cover layer 20 may be the same as or different from the material of the layers 12. The embodiments of the filtration means 10 shown in Figures 1, 3 and 4 comprise ordered linear channels. These channels can be aligned in a precise arrangement, that is, the channels of each layer are aligned with the channels of the other layers, presenting by this a regular, aligned pore configuration. Alternatively, these channels may be displaced in a regular, repetitive manner or may be displaced in a controlled manner. In addition, other configurations of channels and layers are contemplated. Figures 3 and 4 illustrate an embodiment according to the present invention wherein numerous layers 12 of filtration means 80 having structured surfaces 13 are stacked in a controlled and orderly manner, but not necessarily in an aligned manner. The resulting stack of layers 12 has been cut, forming a controlled depth volume. Figure 4 illustrates an enlargement of a portion of the filtration means 80 of Figure 3. Each structured surface 13 comprises consistent channels defined by peaks 28 separated by a floor 30. The floor 30 comprises secondary channels 34. (This type of channel configuration will be discussed later herein in relation to Figure 9). The resultant filtration means 80 provides a highly ordered porous surface through which a fluid to be filtered would flow. Then, each available channel 25 provides a path for the fluid through the controlled depth of the filtration means 80. FIG. 5 illustrates one embodiment wherein each layer 41 to 44 of the filtration means 40 has a different channel configuration and layers 41 to 44 are arranged in repetitive patterns variant with respect to each other. As can be seen, the layer 41 comprises consistent wide channels 47, the layer 42 comprises narrower constricted channels 48, the layer 43 comprises a repetitive configuration of wide channels 47 and then narrow channels 48 and layer 44 comprises a repetitive configuration of two channels narrow 48, then a channel a broad channel 47. The channel repeat configurations could also be random or the selection of the layers comprising the stack could be done in a configuration or in a random manner. In any case, these configurations would still create ordered trajectories because the aperture sizes and channel structures formed would be as expected. Figure 6 illustrates a mode of filtration means 45 wherein the channels 49 of each layer 46 are consistent, but the relationship of the layers 46 to each other is an alternating configuration. The choice of channel configurations, number of channels and layer relationships depends on the particular application for which the filtering means are desired. Figure 11 illustrates an embodiment wherein the filtration means 60 comprises similar layers 62, 63 and 70 having channels 64 defined by peaks 65 within the structured surface 61. However, the layers 62, 63 and 70 differ in their orientation and configuration of repetition one with respect to the other. Layer 62 is a front facing layer, while layers 63 and 70 are layers facing downward. These layers 62, 63 and 70 are all arranged in a variable stack configuration, in which the additional layers 66, 68 and 69 are included. As illustrated, the layers can be arranged facing each other, facing each other or they can be stacked in the same orientation. In addition, the repetition pattern with respect to each other may provide aligned channels or shifted channels in numerous variations. As is evident from Figures 5, 6 and 11, the configurations of -jjSfcj ^ ág¿ * 'channel and layer available with the present invention. They provide versatility and adaptability to meet any filtration requirement. Although the embodiment of Figure 1 is shown with structured surfaces 13 comprising multiple peaks 28 and broad floors 30, provided continuously from one side edge 14 to the other side edge 15, other channel configurations are contemplated. In most cases, it will be desirable to provide a series of peaks 38 completely from one edge 14 of layer 12 to the other edge 15; however, for some applications, it may be desirable to extend the peaks 28 only along a portion of the structured surface 13 on any given layer 12. Furthermore, a specific application for the filtering means 10 can determine the number, type and size of the channels 25 provided to meet the filtration requirements. For example, as shown in Figure 7, channels 16 are defined by a continuous series of peaks 18 that are not separated by a floor. Accordingly, the side walls 17 of each successive peak 18 converge to define a line at the base of the channel 16. A filtration means 10 'formed of stacks of layers 12 having this type of channel 16 is shown in Figure 2. In Figure 8, the channels 25 are defined by a continuous series of dUH ll-a ba ^ ki peaks 27 that are separated by a flat broad floor 30. Each peak 27 is flattened at "the top, thereby facilitating the bonding or bonding to an adjacent layer.In Figure 9 (also as in 3 and 4), the wide channels 32 are defined between peaks 29, but instead of providing a flat floor between the side walls 31 of the channel, a plurality of smaller subpieces 33 are provided. These subpieces 33 thus define secondary channels 34 between them The subpieces 33 may or may not rise to the same level as the peaks 29 and as illustrated, create a first broad channel 32 that includes smaller channels 34 distributed therein The peaks 29 and sub-peaks 33 do not need to be uniformly distributed, one with respect to the other or to each other This configuration has the additional advantage of increasing the amount of channel surface area on which the particulate material may collide during filtration. In addition, the smaller channels 34 can be used to control the flow of fluid through the larger channels 32. Although FIGS. 1-11 illustrate linearly configured elongated channels, the channels can be provided in many other configurations. For example, the channels could have varying cross-sectional widths along the length of the channel; that is, the channels could diverge and / or converge along the length of the channel.

- "- * ^ ----- ^ -" - • "The side walls of the channel could also be contoured instead of straight in the direction of channel extension or channel height In general, any configuration of channel that can provide at least multiple discrete channel portions extending from a first point to a second point within the filtration means are contemplated.Filtering media with structured surface may be particularly useful where it is desirable to circulate a particular fluid through the means for influencing a characteristic of the fluid by its contact with the structured surface (s), that is, the fluid can be treated by passing through the channels defined by the (s) Surface (s) The fluid treatment could include chemical, catalytic and ionization reactions promoted by the constituents placed on, on or through the canal surfaces. ionization reactions can include reactions promoted by electron beam, actinic light and ultraviolet radiation. Separation treatments such as absorption of fluid constituents on properly prepared channel surfaces would be effective due to the high ratio of channel surface area to channel volume. The same attributes could be used to enable the sensing or detection of a fluid through which the surface layer (s) acts as the interface component to the fluid in a sensor or detector system. A fluid detection system could verify the conductivity of the fluid, pH, temperature or composition. Alternatively, a fluid influenced by the surrounding environment as it flows through the channels could be verified as part of a detection system where the device would function by itself as an element in a sensing or sensing system. The surface of the flow channels could also be made functional to respond to or detect these physical conditions. Heating or cooling could be used to thermally treat the fluid. It could also be made that fluid streams of different composition are fused together to interact and treat each other as a means to cause a reaction, dilution or mixing. An observation, detection or analytical device such as a microscope or spectrometer, away from the media can be used to analyze the fluid as it passes in a thin film through the channels. In any case, as with any of the indicated modalities, the structure can be elaborated from flexible, semi-rigid or rigid materials. In another embodiment of the filtering means 50, as shown in Figure 10, the structured surface 51 comprises channels 52 which are defined by a series of peaks 54 having heads 56 with adjacent protruding channels 52. Although these peaks are shown 54 and heads 56 as a mushroom-like feature, any configuration with heads is contemplated. The front layers 58 and 59 comprising such channels 52 are stacked together by the displacement of the channels 52 of the layers 58 and 59 and the coupling of the peaks 54 and heads 56 of a layer 56 with the peaks 54 and heads 56 of the other layer 59. Thus, the peak 54 and head 56 of a layer 58 are located within a channel 52 of the other layer 59. A plurality of these coupled layers 58 and 59 are then stacked together to form the filtration means 50. Alternatively, the layers 58 and 59 may be non-facing layers, stacked together in such a way that the unstructured surface 57 serves as a cover for an adjacent layer (not shown). As with the other modalities discussed above, the layers may or may not be glued together as a stack. The channel structure resulting from this embodiment has the advantage of increasing the surface area of the channel in contact with the fluid that is filtered, thus improving the removal of particles. Alternatively, the filtration means 50 can be formed of stacked layers 80 wherein the structured surfaces 82 comprise ordered arrays of discrete, head-like protrusions 84, as shown in Figure 12, instead of head channels. These protuberances 84 can also be formed as fungus-like structures, but other structures with heads are contemplated. The protuberances 84 can be formed in an array aligned on the structured surface 82 or they can be formed in a displaced array or other ordered configuration. The layers 80 comprising these protrusions 84 can be stacked together by facing the layers 80 and coupling the protuberances 84 of one layer 90 between the protuberances 84 of the other layer 80, similar to the layers 58 and 59 of Figure 10. The protuberances of a layer do not need to be the same as the protuberances of an adjacent layer. Alternatively, the layers 80 can be non-facing layers, stacked together in such a way that the unstructured surface 83 serves as a cover for an adjacent layer. Either if the layers 58, 59 and 80 are formed of discrete head channels or protrusions, ordered fluid paths are provided through the filtration means. These types of layers provide the additional advantage of increasing the percentage of openings per volume without decreasing the surface area, that is, decreasing the percent strength with with respect to the surface area of the face, thereby improving the filtration efficiency without increasing the flow resistance. In some embodiments of the present invention, the structured surfaces 13 of the filtration means 10 are microstructured surfaces defining discrete flow channels, in which those contemplated above are included. As used herein, aspect ratio means the proportion of the length of a channel to its hydraulic radius and hydraulic radius is the wettable cross-sectional area of a channel divided by its circumference of wettable channel. When one embodiment of the present invention comprises discrete flow channels, each channel may have a proportion of minimum aspect (length / hydraulic radius) of 10: 1, in some embodiments greater than about 100: 1 and in other embodiments at least about 1000: 1. At the upper end, the aspect ratio could be infinitely high, but in general it would be less than approximately 1,000,000: 1. Also, with such embodiments, a hydraulic radius of a channel is preferably not greater than about 300 microns. In many modalities, it may be less than 100 micras and may be less than 10 micras. Although smaller is in general better for many applications (and the hydraulic radio could being submicroscopic in size), the hydraulic radius would commonly not be less than 1 miera for most modalities. These proportions are exemplary and are not intended to be limiting. The structured surface 13 of each layer 12 can also be provided with a very low profile. Thus, filtration means are contemplated wherein the structured polymeric layer has a thickness of less than 5000 microns and still possibly less than 1500 microns. To do this, the channels can be defined by peaks that have a height of about 5 to 1200 microns and have a peak distance of about 10 to 2000 microns. However, it will be understood that specific peak heights and peak distances are not as important as a ratio of the overall solidity percent to surface area in the resulting filter media. It could be advantageous in certain applications where the flow resistance is critical, increasing the pore size, such as by increasing the cross section of the channel, thereby reducing the percentage of particle capture but increasing the flow of the fluid through the filter . In other applications, it could be more advantageous to decrease the pore size and increase the pore amount to take advantage particularly of the exclusion of particles and the expanded surface area, as opposed to the mechanisms of .. «- ^ ...... ^ ... ^^ fe ^ BlJ, .. ^^., ^^ ..., ^^. .-. - ^^, _ *, ¿^ - capture of particles. The present invention has the distinct advantage of providing the ability to adapt the filtration means in a very controlled and predictable manner, thereby enabling the production of these types of filtration media specific to the application. The microstructured surfaces useful er. some embodiments of the present invention provide flow systems in which the volume of the system is highly distributed. That is, the volume of fluid that passes through such flow systems is distributed over a large area. This aspect is highly beneficial for many filtration applications. Such microstructured surfaces can be made by known techniques in which microreplication is included, which, as used in this application, means the production of a microstructured surface by means of a process wherein the structured surface characteristics retain a characteristic fidelity individual during the manufacture, from product to product, which varies no more than approximately 50 microns. The microreplicated surfaces are preferably produced in such a way that the structured surface characteristics retain an individual characteristic fidelity during manufacture, from product to product that varies no more than 25 microns.^^^ 8¡ ^^? ,. ^ ^ '. & Referring again to Figures 1, 3 and 4, at least some, if not all, of the channels 25 are open on the front side 22 of the filtration means 10, forming pores on the surface 24 of the face . The fluid passes to the filtration means 10 on the surface 24 of the face, preferably traveling through the channels 25 and exiting on the rear side 23 of the filtration means 10. At least, the structured surfaces of the present invention provide trajectories for the fluid controlled and ordered through the filtration means. The amount of surface area available for filtration purposes is therefore determined by the volume of the filtration media. In other words, the structured surface characteristics of the layers of the filtration means, such as the length of the channels and the channel configurations, define the usable surface area and only the surface of the face. A single layer provided with a structured surface may also comprise functional filtration means according to the present invention. Specifically, this structured surface can function to separate particles from a fluid stream by any and all of the separation mechanisms discussed hereinafter, provided that the flow of the fluid to be treated (filtered) is caused to flow to Xjá ^ ggt * ^^ through the trajectories defined by the surface structure. The particle removal mechanisms can be improved by any of the treatments discussed later herein as well. For example, a single layer having any of the structured surfaces disclosed and contemplated in this application could be provided as a surface layer of any conduit, while the fluid that is to run inside the conduit is directed to run at least one both within the structured surface. Mechanisms for the removal of particles available in fibrous filters are also available in the filtration media of the present invention, but without the inherent limitations of the fibrous filter media. The direct interception is dependent on the pore size and the pore size in turn is dependent on the structured surface characteristics, such as channel cross section and channel configuration. Under the present invention, structured surface characteristics can be produced as channels in widely varying sizes and configurations in a consistent, controlled and predictable manner not available in fibrous and especially woven filters. A filtration medium of stacked structured layers provides a highly ordered and mechanically stable porous surface without the pore size variability and coarse irregularities of the non-woven fabrics. Any pore size variability or irregularities are planned and controlled based on the final filtration needs for which the filtration media of the present invention is designed. As a result, the fluid flow is subjected to a uniform treatment as it passes through the front surface of the filtration means, thus improving its filtration efficiency. Inertial impact and diffusional interception also occur in the filtration media of the present invention. Both of these removal mechanisms are dependent on the surface area available within the filtration media. In fibrous filters, the surface area of the individual fibers provides this surface area. In the present invention (either a single layer or a stack of layers) this surface area is provided by the surface area of the structured surface features in which channels are included whose surface area is defined by the configuration and length of the channel. As the fluid stream passes through stacked layer filtration media via ordered fluid paths, particles smaller than the pore size of the front surface will impact the sidewalls, floor coverings and other characteristics of structured surfaces due to their Brownian density or motion, as described above for fibrous filters. The use of structured surfaces comprising channels with various channel configurations can improve this capacity. Restricting fluid flow to discrete channels using glued layers can further improve this capacity or can be further improved by not restricting the flow of the channel-to-channel fluid. Then the flow of the fluid would be allowed between channels to a limited extent, thereby increasing the surface area 10 that contacts or adjacent to the fluid stream. Unlike fibrous filters, however, the filtration media of the present invention does not serve as a surface charge filter that is subjected to surface sealing, but instead serves as a deep bed filter utilizing all The volume of the filtration media to improve its efficiency and filtration capacity and still works at a low resistance to flow. This characteristic is due to the low percentage of solidity obtainable with the present invention, also as a lower probability of the blockage of the through channel and the consistency of the pores and channels in the entire surface area of the face, resulting from the controlled formation process and predictable This ability to serve as a deep-bed filter 25 can be further improved by the choice of • - • ^ - - - -a > ..- i ~ .- • - - - ----- - n ^. . «Fc. ^ ...» ^ .. ^ ... ».,., ...». ^, - -. - ^^ - structured surfaces including channel configuration, such as those shown in Figures 4, 9 and 10, wherein the available surface area within each channel is increased by additional sub-channels or other structural additions. Accordingly, the capacity and efficiency of the filtration media of the present invention are extensively improved with respect to those of a fibrous filter having the same face surface area in both low and high surface velocity applications. Additional advantages of the filtration means of the invention include the ability to be manufactured in various ranges of pore sizes and depths with accuracy and reliability. They can be produced with the characteristic sizes, overall density and base materials currently applied to non-woven and fibrous filters, but have the additional advantages described above. While the traditional fibrous filter media can be folded or used flat, the filtering means of the present invention can be formed in a multitude of self-supported configurations. They can be shaped into shapes, laid on objects, have force applied without crushing and without closing the channels. In addition, the ability of the filtration media to be used in three-dimensional form, instead of the flat form of fibrous filters, offers an array of new configurations of final product, especially because of its stability to serve as a rigid structural element in a design. The filtration means of the present invention also have the additional advantage of not being susceptible to breakage caused by manipulation of the filtration means for example by folding, handling or assembly. Fiber rupture in conventional fibrous filters can cause a variety of problems, especially in room cleaning applications. Another advantage is the ability to form the structured surfaces of the layers to direct the flow path in a desired manner. An example of the filter media that is used in a final product is shown in Figure 13. A respirator mask having double filters is shown with the filter media of the present invention that is used as the filters. The use of filtration media in this type of application reduces the volume and weight of the mask by eliminating the need for filter containers that are commonly needed to obtain the necessary filtration capacity of the mask. In order to improve the filtering capabilities or to effect a desired result, the filtering means of the invention can be treated in numerous ways. An example of treatment is shown in Figure 11. The filtration means 60 comprises a stack of layers 62, 63 and 70.

... S: Interposed between the layers of Senté 62 and 63 is an additional layer 66 which serves as a cover layer for at least some of the channels 64 of each layer 62 and 63. More than; an additional layer type can be provided between groups. Subsequent layers of front, as shown by the additional layers 66 and 68. In addition, the same or different additional layers 69 can be provided between the non-facing layers 70 to improve the removal of particles c provide other benefits. Any type, size, configuration and ratio of structured surface characteristics are contemplated for use with the additional layers 66, 68 or 69. These additional layers 66, 68 and 69 can be formed from the same or a similar material as the other structured layers. 62, 63 or 70 or may comprise other materials that can provide particulate removal or other desired benefits and are effective for the purpose contemplated. Materials that improve particle removal or obtain other desirable benefits may include, either alone or fixed to a substrate: adsorbents, such as activated carbon, zeolite or aluminisilicate to separate organic molecules or deodorization; deodorization catalysts such as copper - ascorbic acid for the decomposition of malodorous substances; drying agents such as silica gel, zeolite, calcium chloride or active aluminum; a disinfecting agent such as a germicidal UV system, fragrances such as gloxal, esters of methacrylic acid or perfumes; or agents that eliminate ozone in the; which include metals such as Mg, Ag, Fe, Co, Ni, Pt, Pd or Rn or an oxide supported on a carrier such as alumina, silica-alumina, zirconia, diatomaceous earth, zirconium silica or titania. Any of the listed materials other than those that are not listed but would be appropriate to fulfill a desired purpose and are effective with the present invention can be used in any combination. Another type of treatment available to the filtration media of the present invention is either the passive or active electrostatic charge of the filtration material. Electrostatic charging improves the ability of the filter media to separate particulate matter from a fluid stream by increasing the attraction between particles smaller than the pore size and the surface area of the structured surfaces, thus improving the third mechanism for the removal of particles. Particles that do not collide, passing close to the side walls are more easily pulled from the fluid stream and the colliding particles adhere more strongly. Electrostatic charging can be provided by an electret, which is a piece of dielectric material that exhibits an electrical charge that persists for extended periods of time. The materials of J &E; j ^^^^^^ electret loadables include non-polar polymers such as polytetrafluoroethylene (PTFE) and polypropylene. In general, the net charge on an electret is zero or close to zero and its fields are due to charge separation and not caused by a net charge. By means of the appropriate selection of materials and treatments, an electret can be configured in such a way as to produce an external electrostatic field. Such an electret can be considered an electrostatic analog of a permanent magnet. Various methods are used to load dielectric materials, any of which can be used to charge the filtration media of the present invention, in which corona discharge is included, heating and cooling of the material in the presence of a charged field, electrification of contact, spraying the fabric with charged particles and impaction of a surface with jets of water or streams of water droplets. In addition, the load capacity of the surface can be improved by the use of mixed materials. Examples of charging methods are disclosed in the following patents: U.S. Patent No. RE30,782 issued to van Turnhout et al .; U.S. Patent No. RE31,285 issued to van Turnhout et al .; U.S. Patent No. 5,496,507 issued to Angadjivand et al., U.S. Patent No. 5,472,481 issued to Jones et al., U.S. Patent No. 4,215,682 issued to Kubik et al., ^ ^ ^ ^ ^ ^ ^ ^ ^ ^ ^ ^ ^ ^ ^ ^ ^ ^^^^^^ BA ^^^^^^^^ giS ^^^^ US Patent No. 5,057,710 issued to Nishiura et al., US Patent No. 4,952,815 issued to Nakao and patent No. 4,798,850 issued to Brown. Types of active loading include the use of a film with a metallized surface on a face that has a high voltage applied to it. This could be carried out in the present invention by the addition of such a metallized layer adjacent to a structured layer or the application of a metal coating on the unstructured surface of a structured layer. Then the filter media comprising such metallized layers could be mounted in contact with a source of electrical voltage resulting in an electrical flow through the layers of the metallized medium. Examples of such active loading are disclosed in U.S. Patent No. 5,405,434 issued to Inculet. Another type of treatment available for the filtration media of the present invention is the use of fluorochemical additives in the form of additions of material or coatings of material that can improve the ability of the filter to repel oil and water, as well as to improve the capacity of the filter. filter to filter oily aerosols. Examples of such additives are found in U.S. Patent No. 5,472,481 issued to Jones et al., U.S. Patent No. 5,099,026 issued to Crater et al and U.S. Patent No. 5,025,052 issued to Crater et al.

In addition, the filtration media * can be embedded, coated or otherwise treated with a sticky substance designed to attract and adhere the colliding particles. The filtration media can also be embedded, coated or otherwise treated with a chemical reagent or other compound designed to react with the fluid stream, either to improve filtration or produce an additional result. These types of compounds and results are similar to those listed above for the treatment by aggregate layers. These compounds can include adsorbents, such as activated carbon, zeolite or aluminosilicate to separate organic molecules or deodorization; deodorization catalysts such as copper - ascorbic acid for the decomposition of malodorous substances; drying agents such as silica gel, zeolite, calcium chloride or active aluminum; a disinfection agent such as a germicidal UV system; fragrances such as gloxal, esters of methacrylic acid or perfumes; or ozone depleting agents which include metals such as Mg, Ag, Fe, Co, Ni, Pt, Pd or Rn or an oxide supported on a carrier such as alumina, silica alumina, zirconia, diatomaceous earth, silica - zirconia or titania. The elaboration of structured surfaces and in particular microstructured surfaces, on a layer ^ f & amp; & amp; amp; polymer such as a polymeric film are described in U.S. Patent Nos. 5,069,403 and 5,133,516 both issued to Marentic et al. The structured layers can also be microreplicated continuously using the principles or steps described in U.S. Patent 5,691,846 issued to Benson, Jr. et al. Other patents describing microstructured surfaces include U.S. Patent No. 5,514,120 issued to Johnston et al., 5,158,557 issued to Noreen et al., 5,175,030 issued to Lu et al. and 4,668,558 issued to Barber. The structured polymeric layers produced according to such techniques can be microreplicated. The provision of microreplicated structured layers is beneficial because the surfaces can be produced in bulk without substantial variation from product to product and without using relatively complicated processing techniques. "Microreplication" or "microreplication" means the production of an icostructured surface by means of a process wherein the structured surface characteristics retain a fidelity of individual characteristic during manufacture, from product to product, which varies no more than about 50 microns. The microreplicated surfaces are preferably produced in such a way that the structured surface features retain an individual characteristic fidelity during the ^ gjÉf j ^^ - manufacture, from product to product, which varies no more than 25 microns. The layers of the filter media for any of the embodiments of the present invention may be formed from a variety of polymers or copolymers including thermoplastic, thermosettable and curable polymers. As used herein, thermoplastic, as distinguished from thermoformable, refers to a polymer that softens and melts when exposed to heat and re-solidifies when cooled and can be melted and solidified through many cycles . A thermosetting polymer, on the other hand, solidifies irreversibly when heated and cooled. A cured polymer system, in which the polymer chains are interconnected or crosslinked, can be formed at room temperature through the use of chemical agents or ionization irradiation. Polymers useful in the formation of any of the structured layers or articles of the invention include but are not limited to polyolefins such as polyethylene and polyethylene copolymers, polyvinylidene difluoride (PVDF) and polytetrafluoroethylene (PTFE). Other polymeric materials include acetates, cellulose ethers, polyvinyl alcohols, polysaccharides, polyolefins, polyesters, polyamides, polyvinyl chloride, je ^ -Ht. polyurethanes, polyureas, polycarbonates and polystyrene. The structured layers can be molded from curable resin materials such as acrylates and epoxies and cured by promoted free radical routes; chemically, by exposure to heat, UV or electron beam radiation. There are applications where flexible filtering media are desirable. The flexibility can be imparted to a polymeric layer structured using polymers described in U.S. Patents 5,450,235 issued to Smith et al and 5,691,846 issued to Benson, Jr. et al. The entire polymeric layer does not need to be made of a flexible polymeric material. A portion of a layer, for example, could comprise a flexible polymer, while the structured portion or a portion thereof could comprise a more rigid polymer. The patents cited in this paragraph describe the use of polymers of this kind to produce flexible products having microstructured surfaces. Polymeric materials including polymer blends can be modified by melt blending of plasticizing active agents such as surfactants or antimicrobial agents. The surface modification of the structured surfaces can be carried out by means of vapor deposition or covalent grafting of functional portions using ionization radiation. Methods and techniques for polymerization by grafting monomers onto polypropylene, for example, by ionization radiation, are disclosed in U.S. Patent Nos. 4,950,549 and 5,078,925. The polymers may also contain additives that impart various properties to the polymeric structured layer. For example, plasticizers can be added to decrease the elastic modulus to improve flexibility. The filtration means of the present invention start with the desired materials from which the layers are to be formed. Suitable sheets of these materials having the required thickness or thicknesses are formed with the desired surface topography by methods such as microreplication (ie, by molding a film on a roll or band having geometric shapes). A single layer with a structured surface can function as a filter, provided that the flow of gas to be treated is caused to flow through the paths for the fluid defined by the surface structure. A single layer or multiple layers can be additionally used as filters when they are covered or stacked. The stacked layers are oriented in a predetermined configuration or relationship, with or without additional layers, to accumulate an appropriate volume of layers.

^^^^^^^ ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ Then the resulting volume of layers is converted, by cutting or otherwise, into filtering media of a desired thickness. Then these filtration media can be assembled or otherwise assembled into a final usable format. Any desired treatments, as described above, can be applied at any appropriate stage of the manufacturing process. Furthermore, the filtration means according to the present invention can be combined with another filtration material, such as a layer of non-woven fibrous material on the surface of the face or can be combined with another non-filtering material to facilitate such things as manipulation, assembly, assembly or use Preferred embodiments of the invention can use thin flexible polymer films having parallel linear topographies as the carrier element of the microstructure. For purposes of this invention, a "film" is considered to be a thin sheet (less than 5 mm thick) generally flexible of polymeric material. The economic value when using non-expensive films with film surfaces carrying highly defined microstructures is greater. Flexible films can be used in combination with a wide range of other materials and can be used without being supported or efh conjunction with a support body where desired. The filter media formed from such microstructured surfaces and other layers, if provided, may be flexible for many applications but may also be associated with a rigid structural body where applications warrant it. In those embodiments wherein the structured layer or layers of a filter media of the invention include microstructured channels, such devices may employ a multitude of channels per device. As shown in some of the embodiments illustrated above, such microstructured layers can easily possess more than 10 or 100 channels per layer. Some applications may have more than 1,000 or 10,000 channels per layer. All of the patents and patent applications cited above are fully incorporated by reference in this document. Also, this application completely covers by reference the following patent applications that are jointly owned by the assignee of the present invention and are filed on the same date with the same: US patent application Serial No. 09 / 099,269 of Insley et al. entitled "Microchanneled Active Fluid Transport Devices"; U.S. Patent Application Serial No. 09/099, 632 to Insley et al and entitled "Microchanneled Active Fluid Heat Exchanger"; US patent application No. of Series 09 / 100,163 of Insley et al entitled "Microstructured Separation Device" and US Patent Application No. 09 / 099,565 of Insley et al entitled "Fluid Guide Device Having an Open Microstructured Surface for Attachment to a Fluid Transport Device". Although the present invention has been described with reference to preferred embodiments, those skilled in the art will recognize that changes in form or detail can be made without departing from the spirit and scope of the invention. It is noted that, in relation to this date, the best method known to the applicant to carry out the aforementioned invention, is that which is clear from the present description of the invention. - * & * .TJ &OÍ - * -

Claims (13)

1. CLAIMS Having described the invention as above, the content of the following claims is claimed as property: 1. A filtration means, characterized in that it comprises: a plurality of polymeric structured layers having a defined structured surface within each layer, the plurality of Structured layers are configured as a stack, the structured surfaces define a plurality of open ordered openings through a stack face and corresponding ordered fluid paths that form an ordered pore volume.
2. 2. The filtration medium according to claim 1, characterized in that the trajectories for the ordered fluid are defined by a plurality of flow channels formed within the structured surfaces of the structured layers.
3. 3. The filtration medium according to claims 1-2, characterized in that the plurality of flow channels are defined by a series of peaks, each peak has two side walls.
4. 4. The filtration medium according to claim 3, characterized in that the side walls and the adjacent peaks of the flow channels are separated by a flat floor 5. The filtration means according to claim 3, characterized in that the side walls of adjacent peaks of the channels of flow are separated by at least one sub-apex, the sub-apex defines a plurality of subchannels within each flow channel or wherein the peaks comprise projecting heads adjacent to the flow channels and the structured layers comprise flow channels with peaks of flow heads. in front of each other, the head peaks of a front structured layer are coupled to the head peaks of the other front structured layer 6. The filter medium according to claims 1-5, characterized in that a flow channel of a structured layer is configured differently from a flow channel of another structured layer 7. The filtration medium according to claim 2, characterized in that the flow channels of a The structured layer is displaced relative to the flow channels of an adjacent structured layer within the stack. 8. The filtration medium according to claims 1-7, characterized in that the ordered fluid paths are defined by a plurality of discrete protuberances formed in an ordered configuration within the structured surfaces of the structured layers and wherein § (ordered configuration of discrete protuberances is an essentially aligned arrangement.) 9. The filtration medium according to claims 1-7, characterized in that two of the structured layers face each other, the discrete protuberances of the front layers. they are coupled together in an orderly manner 10. The filtration medium according to claims 1-9, characterized in that at least a portion of the plurality of structured layers are bonded together 11. The filtration means in accordance with claims 1-10, characterized in that it further comprises a cover layer that covers at least minus one portion of one of the plurality of structured layers. 12. The filtration medium according to claims 1-10, characterized in that it further comprises at least one additional layer located between two adjacent structured layers for the purpose of improving filtration performance. The filtration medium according to claim 12, characterized in that the two adjacent structured layers face each other with the additional layer between them. ^^^^^^^^ ™ ^^^^^^^^^^^^^^^^^^^^ ^^^ 4 ^^^^^^ j & - Z t 14. The filtration medium according to claim 12, characterized in that the additional layer is an electret. 15. The filtration medium according to claim 12, characterized in that the additional layer comprises a material to provide at least one of the benefits of improved particulate removal filtration, oil and water repellency, odor elimination, organic matter removal, ozone removal, disinfection, drying and introduction of fragrance. 16. The filtration medium according to claims 1-15, characterized in that at least a portion of the plurality of structured polymeric layers contain polytetrafluoroethylene or polypropylene. 17. The filtration medium according to claims 1-16, characterized in that at least a portion of the plurality of structured layers are treated for the purpose of improving filtration performance. 18. The filtration medium according to claim 1-17, characterized in that the structured layer comprises electret material. 19. The filtration medium according to claims 17-18, characterized in that the structured layers comprise a material to provide at least one of the benefits of improved removal filtration. S = ^^ j ^ X ^ a¡g ^ y? ¿£ _ ^; g ^ ** ^ ^ of particles, oil and water repellency, elimination of odors, elimination of organic matter, elimination of ozone, disinfection, drying and introduction of fragrance. 20. A filtration method characterized in that it comprises: (a) positioning the filtration means according to claim 1 in a path for fluid flow; (b) passing the fluid through the filtration means and (c) separating the particles from the fluid in the filtration medium. The method of claim 20, characterized in that the structured layers are capable of providing at least one of the benefits of improved particulate removal filtration, oil and water repellency, odor elimination, organic matter removal, elimination of ozone, disinfection, drying and introduction of fragrance. 22. The method according to claims 20-21, characterized in that the structured layers are in the form of an electret. 23. The method according to claims 20-22, characterized in that the structured layers are metallized. 24. The method of claims 20-24, characterized in that at least one additional layer is disposed between adjacent structured layers for the purpose of providing the filtering benefits. 26. A method of making filtration media, characterized in that it comprises: (a) providing a plurality of structured layers having a defined structured surface within each layer and (b) stacking the plurality of structured layers with the structured surfaces that define a plurality of ordered open entries across a stack face and corresponding ordered fluid paths, thereby forming an ordered pore volume. The method of claim 26, characterized in that it further comprises gluing at least a portion of the plurality of structured layers within the ordered pore volume. The method according to any of claims 26-27, characterized in that it further comprises cutting the stack of structured layers and providing at least a portion of the cut pile to form an ordered pore volume of a specific thickness. 29. The method according to claims 26-28, characterized in that it also comprises ^^ 8 ^^^^^^ / «i) * í to treat at least a portion of the plurality of structured layers to provide at least one of the benefits of improved particulate removal filtration, oil and water repellency, odor elimination, elimination of organic matter, ozone elimination, disinfection, drying and introduction of fragrance. 30. The method according to claim 26-29, characterized in that it further comprises charging at least a portion of the plurality of structured layers to form an electret. 31. The method according to claims 26-30, characterized in that it further comprises metallizing at least a portion of the plurality of structured layers and actively loading the metallized layers by connecting the metallized plates to a voltage source during the use of the medium. of filtration. 32. The method of claims 26-31, characterized in that it further comprises the surface coating of at least a portion of the plurality of structured layers. The method according to claims 26-32, characterized in that it further comprises the addition of at least one additional layer between adjacent structured layers for the purpose of providing the filtering benefits. 34. A filtration means characterized in that it comprises: (a) at least one polymer structured layer having a first major surface having a defined structured surface within the layer, the structured surface provides several trajectories for the fluid, ordered and at least a portion of the structured surface having a treatment to improve its particle removal capacity as compared to a similar structured polymeric layer without such treatment. 35. The filtration medium according to claim 34, characterized in that the structured layer comprises an electret. 36. The filtration medium of claims 34-35, characterized in that at least a portion of the structured layer is electrostatically charged. 37. The filtration medium according to claims 34-36, characterized in that at least a portion of the structured layer is treated with a sticky or adherent substance. 38. The filtration medium according to claims 34-37, characterized in that it further comprises a cover layer covering at least a portion of the structured layer. 39. The filtration means according to claims 34-38, characterized in that it further comprises a plurality of polymeric structured layers, each having a first main surface having a structured surface defined within the layer, the plurality of structured layers being configured as a stack, the structured surfaces define a plurality of open ordered entries through a stack face and corresponding ordered fluid paths that form an ordered pore volume. i. *.