MXPA99002331A

MXPA99002331A - Porous structures and process for the manufacture thereof

Info

Publication number: MXPA99002331A
Application number: MXPA/A/1999/002331A
Authority: MX
Inventors: Chen Weichih
Original assignee: Cuno Incorporated
Priority date: 1996-09-10
Filing date: 1999-03-10
Publication date: 2000-05-01

Abstract

A process of the manufacture of porous structures comprises forming a dry mixture comprising a component providing primary separation capability, a component providing green strength reinforcement capability and a component providing binding capability and selected from the group consisting of thermoplastic and thermosetting polymers;delivering the mixture to a suitable surface and building a desired thickness thereof;densifying the mixture into the form desired for the porous structure;removing the densified porous structure from the surface;binding the component providing the primary separation capability by melting the mixture to a temperature of up to about 20°C higher than the melting point of any thermoplastic component providing binding capability. Porous structures (100, 110, 120, 125, 140, 175) according to the present invention comprise from about 70 to about 90 parts by weight of a component providing primary separation capability (61, 62);from about one to about 15 parts by weight of a component providing green strength reinforcement capability (64, 65);and from about 8 to about 20 parts by weight of a component providing binding capability (67, 68) and selected from the group consisting of thermoplastic and thermosetting polymers.

Description

* POROUS STRUCTURES AND PROCESS FOR THE V MANUFACTURING THEMSELVES TECHNICAL FIELD 5 This invention relates to porous structures for the separation of fluids from undesired constituents. Typically, media of this type contain filtering aids and are manufactured in the form of cylindrical blocks of hollow core or flat sheets.

In use, the fluids to be separated are sent through the porous filter structure, after which they are removed. The present invention also provides a process for the manufacture of those porous structures. BACKGROUND OF THE INVENTION Typical separation media include, diatomaceous earth, pearlite, activated carbon, zeolites and the like, to achieve the filtering of the effects of adsorption. The use of such components in powder form often generates a high pressure drop and / or channeling. Accordingly, powdered filtering aids are arranged in useful ways by means of a) incorporating them into a fine medium such as paper or deposit them as a thin pre-coating on a P1131 / 99MX substrate to avoid high pressure drop; or b) combine them with a binder so that they can later be transformed into a useful porous structure. Molded porous filter structures made from typical separation media could be improved if the amount of binder could be decreased from the usual 20 to 40 percent and if the molded object could be removed from the compression high pressure mold, ie, if it had high green resistance and then thermally deposited in a condition of self-support. The porous filter structures can be made by an extrusion process, although this process is slow and requires a large number of extruders for commercial production. Furthermore, these processes are limited in terms of the forms of useful filter structures that can be made. The filtering structures can be made by wet or dry processing. An example of the wet process is U.S. Patent No. 5,443,735 issued to Pall Corporation, which relates to the manufacture of so-called immobilized carbon beds. Several methods are exposed, one of which produces a radial flow pressing block filter by mixing a wet pulp of materials P1131 / 99MX fibrous, activated carbon and an adhesive; pumping the pulp into a mold; expelling surplus water; removing the block from the mold and heating it to remove moisture and adding filtering materials. Another produces an axial flow filter that includes the mixture of carbon particulate and finely powdered polyethylene resin; The mixture is then heated to melt the polymer and bond the carbon particles. The invention is based on the use of fine particles of brass to aid in the inhibition of microbial growth in water. In the dry process, the components are first mixed dry, followed by densification and heating of the dry mix in different ways and forms. The current state of the dry process technique is exemplified by the following patents: U.S. Patent No. 4,664,683 issued to Pall Corporation shows the use of molded carbon blocks with particle sizes from about 200 to 2000 microns. The maximum molding pressure is 400 psi. The particle size of the pulverized polyethylene binder employed is between about 8 to 30 microns. The preferred agglutination pressure is from 0.3 to 10 psi. The agglutination temperature is between about 50 to 902F (28 to 50aC) above the P1131 / 99MX Vicat softening temperature. These temperatures are equal to or lower than the melting temperature of the binder. The mixture of carbon and binder is heated inside the mold and pressed for 1 or 2 minutes. The cooled carbon block is removed from the mold and found to be self-sustaining. The filter blocks have little physical resistance due to the lack of an efficient bond between the binder and the carbon particles. U.S. Patent No. 4 4No. 859,386 issued to Am a Corporation describes a method for making a molded composite carbon filter having two layers that includes the use of ultra high molecular weight polyethylene as a binder, with a very low melt flow rate, in the order of <; 1 gram / 10 minutes, at a level between 20 and 35 percent by weight. Binders having a high melt flow rate are mentioned as a cause of clogging of active activated carbon sites. The patent shows that while the blocks are still in the mold, they are subjected to heat (175 to 205aC) and pressure (30 to 120 psi) to form a united integral composite filter. The drawback of this type of block is its weak physical strength due to the poor melting flow of the binder. At temperatures just a few degrees down P1131 / 99MX above the melting temperature (135 to 1382C), the block has very poor physical strength. The method depends on raising the temperature from 175 to 205aC to increase the melt flow, which is avoided in the first place, to improve the bonding strength. U.S. Patent No. 5,019,311 issued to KT Corporation describes a similar process, which employs a mixture of conventional binders having medium and high melt flow rates. These conventional binders are spread in a "continuous network matrix" (C M) due to the shear forces encountered during the mixing of the material before extrusion without blocking the active sites, at a temperature considerably higher than the softening point of the binder. As a consequence, the required amount of the binder can be significantly reduced from about 8 to 20 weight percent. During the extrusion process, the medium is in contact with the barrel and the screw. The extruded medium is very hot and soft and must be hardened by rapid cooling to allow subsequent handling. The typical binder, the ethylene-vinyl acetate copolymer (EVA), used in this invention is cut at a minimum temperature of 145 BC, which is at least 302C higher than the P1131 / 99MX melting temperature (115aC). The binder is stretched and spread on the carbon particles to give a good bonding strength. However, this process can plug an excessive number of carbon pores. In addition, the capacity and efficiency of carbon adsorption are very sensitive to the variation of the temperature and the cutting force of this process. Thus, while attempts have so far been made to manufacture porous structures containing filter aids with fine particle size, the technique has not provided an easy process by which relatively low amounts of binder resin are combined with fine particles. to produce a block that has good resistance in green and a favorable low pressure drop during the separation or filtration of fluids.

SUMMARY OF THE INVENTION It is therefore an object of the present invention to provide a process for the manufacture of porous structures. It is another object of the present invention to provide a process for the manufacture of porous structures consisting of P1131 / 99MX fine fibrous and particulate separation and binders. It is still another object of the present invention to provide porous structures consisting of fine separation materials and binders. It is yet another object of the present invention to provide porous structures that provide adsorbent and non-adsorbent media. It is still another object of the present invention to provide porous structures consisting of larger amounts of separation materials and respectively smaller amounts of binders without sacrificing green strength. It is yet another object of the present invention to provide a process for the manufacture of porous structures having larger amounts of separation materials and lesser amounts of binders, without sacrificing green strength. At least one or more of the objects mentioned above, together with the advantages thereof with respect to the known technique related to the porous structures and the processes for the preparation thereof, which will be evident from the following specification , are made by the invention in the manner that is later P1131 / 99MX describes and claims. In general, the present invention is directed to a process for the manufacture of porous structures consisting in forming a dry mixture consisting of a component that provides primary separation capacity, a component that provides green strength strengthening capacity and a component which provides agglutination capacity and is selected from the group consisting of thermoplastic and thermosetting polymers; distribute the mixture on a suitable surface and make an adequate thickness of it; densify the mixture in the desired form for the porous structure; remove the densified porous structure from the surface; agglutinate the component that provides the primary separation capacity by heating the mixture to a temperature up to about 202C above the melting point of any of the thermoplastic components that provide the binding capacity. The present invention also provides porous structures comprising between about 70 and about 90 weight percent of a component that provides primary separation capacity; between about one and about 15 weight percent of a component that provides P1131 / 99MX resistance strengthening capacity in green; and between about eight and about 20 weight percent of a component that provides agglutination ability and is selected from the group consisting of thermoplastic and thermosetting polymers.

BRIEF DESCRIPTION OF THE DRAWINGS Figures 1A-1D provides a series of steps that describe means for compression of components in the manufacture of the porous structures, according to the present invention; Figures 2A-2C provides a series of steps that schematically describe other means for compressing components in the manufacture of the porous structures, according to the present invention; Figures 3A-3B are block diagrams describing various combinations of steps for the manufacture of porous structures according to the present invention; Figure 4 is a diagrammatic description of various combinations of components and processing steps for the manufacture of the porous structures according to the present invention; Figures 5 -5B provides a sequential description of three components in sequence P1131 / 99MX combined for the manufacture of the porous structures before compression and heating in Figure 5A and after compression and heating in Figure 5B, according to the present invention; Figures 6A-6C sequentially provide a schematic description of two combined components for the manufacture of the porous structures before compression and heating in Figure 6A and after compression and heating in Figures 6B and 6C, according to present invention; Figures 7A-7B sequentially provide a schematic description of a component for the manufacture of the porous structures before compression and heating in Figure 7A and after compression and heating in Figure 7B, according to the present invention; Figure 8 is an enlarged cross-section, taken substantially along the lines 8-8 of Figure 7, of a multicomponent polymer fiber that can be used for the manufacture of the porous structures according to the present invention. Figure 9 describes two multi-component polymer fibers used for the manufacture of porous structures according to the present invention which shows a portion of the outer polymeric sheath of Pll3l / 99MX each of the fibers fused together; Figure 10 is a partial side elevation of a porous structure according to the present invention; Figure 11 is an enlarged view of the area circulated in Figure 10; Figure 12 is a partial side elevation of another porous structure according to the present invention; Figure 13 is a partial side elevation of another porous structure according to the present invention; Figure 14 is a side elevation, partially in section, describing another porous structure according to the present invention, having a closed end; Figure 15 is a side elevation, partially in section, describing a mold together with a plurality of removable jackets for the manufacture of multi-layer cylindrical porous structures; Figure 16 is a side elevation, partially in section, describing a portion of a multi-layer cylindrical porous structure product, according to the present invention; Figure 17A is a side elevation, partially in section, describing a mold together with an apparatus, described in a manner P1131 / 99MX schematic for the manufacture of multilayer cylindrical porous structures; Figure 17B is a side elevation, partially in section, describing a mold like that of Figure 17A, partially filled; Figure 17C is a side elevation, partially in section, describing a mold like that of Figures 17A-B, which describes a densified multi-layer cylindrical porous structure; Figure 18 is a schematic description of an apparatus for manufacturing multi-layer flat sheet porous structures, according to the present invention; and Figure 19 is a cross-section through a portion of a multi-layer flat sheet porous structure product, according to the present invention; Figure 20 is a perspective view of a non-fibrillated fibrous component that can be employed as a component of the porous structures of the present invention; Figure 22 is a perspective view of a fibrillated fibrous component that can be employed as a component of the porous structures of the present invention; and Figure 22 is a graph comparing the effectP1131 / 99MX on the green resistance of the porous structures, according to the present invention, with the increase in the additive amounts of polyethylene fibers.

PREFERRED MODALITY FOR CARRYING OUT THE INVENTION The present invention relates to the manufacture of porous structures, useful in separation applications, particularly filtration and a new and useful form of blocks and other configurations thereof. The porous structures comprise 1) a component that provides primary separation capacity or primary medium (PM); 2) a component that provides strength reinforcement in green or green resistance agent (GSA); and 3) a component that provides agglutination capacity or binder (B). One or more types of each component can be combined. Optional components (4) include various additives, as will be described below. Optional additives usually do not change the main functions of PM, GSA and B. However, the additive may become part of PM, GSA and / or B when the additive contribution is significant. With respect to the primary separation medium, this may be one or more types of particles or fibers in mixtures that function as the porous matrix. From P1131 / 99MX preference, the primary medium is selected from the group consisting of carbon particles, diatomaceous earth, perlite, activated alumina, silica, zeolites, natural fibers and artificial or synthetic fibers. Typically pulverized coal is selected to form a porous carbon block structure and comprises a particle size between 10 to 400 microns. For a general description of suitable carbon, see U.S. Patent No. 4,859,386, the subject matter of which is hereby incorporated by reference. Activated carbon is available in Calgon, Barnebey and Sutcliffe, etc. Sizes for other particulate media are generally well known to those skilled in the art and therefore, do not constitute a limitation to the practice of the present invention. Likewise, the dimensions of the fiber, for example, denier, length, diameter and the like can also be varied in the manner known for the manufacture of various porous structures based on fibrous media. With respect to fibers, natural species include cellulose such as cotton and wood pulp, wool, jute, hemp and artificial and synthetic varieties include polyolefin fibers derived from monomers having between two and P1131 / 99MX approximately five carbon atoms such as polyethylene and polypropylene, as well as polyester, carbon, graphite, glass, acrylic, rayon, nylon and aramid fibers. In some cases, multi-component fibers having a polypropylene or polyester core and a lower melting polyethylene sheath may be selected, as will be described below. Such fibers are commercially available and an example comprises a high density polyethylene sheath (HDPE) and a polypropylene (PP) core. The primary medium may also include certain plastic powders including polyolefins that are derived from monomers having from two to about five carbon atoms, such as polyethylene and polypropylene, as well as polystyrene, polyvinyl chloride, polycarbonate, polysulfone, nylon and polyester. Now it is evident that some primary media species are not meltable or at least do not melt during the manufacture of the porous structure, while other species can melt and melt partially or completely. Where the primary medium does not melt, adsorbent porous media can be made; however, both adsorbent and non-adsorbent porous media can be made from both fusible primary media and non-fusible media, which can be P1131 / 99MX will explain in more detail later. Examples of adsorbent primary media that do not melt or not melt include activated carbon, ion exchange resins, alumina and zeolites. Examples of primary non-adsorbent media that do not melt or melt include natural and synthetic fibers. Examples of non-adsorbent media made of fusible primary media include multicomponent fibers. As for the green resistance agent, fibers and powders can be used. While powders are less effective, fine fibers are more effective than thick fibers. Smooth or crimped fibers are less effective than fibrillated fibers. Soft fibers are more effective than rigid fibers. Preferred fibers are fibrillated or microfibers, selected from the group consisting of polyolefin fibers such as polyethylene or polypropylene, polyesters, nylons, aramides and rayons. These fibers, if they melt, can also function as binders or as part of the porous matrix, depending on their physical and chemical nature and porous condition. The preferred diameter of these types of fibers is less than 100 microns, but is not limited. The amount of the green resistance agent and the compression pressures are the P1131 / 99MX processing variables for a specific formulation. Other types of green strength agents include liquid green strength agents such as latex and resinous solutions. Styrene-butadiene latex, poly (ethylene-vinyl acetate) and acrylic types are good candidates. Aqueous resin solutions made of water-soluble polymers, such as methyl cellulose and hydroxypropylmethyl cellulose, carboxymethyl cellulose, hydroxyethyl cellulose, polyvinyl alcohol, polyvinyl pyrrolidone, polyacrylic acid, polyethylene oxide, polyethylene imine, polyacrylamide, natural gums and their copolymers and Derivatives can also be used, separated or in mixtures. Even small amounts of water can be used to soften the dry pulverized thermosettable binder resins, such as phenol-formaldehyde and melamine-formaldehyde resins to improve green strength and thus, water can be used as a green strength agent. The binder material can be in the form of powder or fibers or mixtures thereof, it is preferred with thermoplastic or thermosetting plastics. Fibrous binders can include multicomponent and fibrillated fibers and also P1131 / 99MX may have some separation properties. It is preferred that the binder have average melt indexes, to improve physical strength, reduce melt flow and reduce the time required to thermally bind the medium. The preferred melt index is > 1 gram per 10 minutes (ASTM 1238 method) to about 20 grams per 10 minutes for adsorbent and non-adsorbent media. More particularly, the powdered materials are selected from the group consisting of polymer powders, which are derived from monomers having between two and about five carbon atoms, such as polyolefins for example, polyethylene and polypropylene; as well as epoxy resin, phenol-formaldehyde and melamine formaldehyde powders. These polymer powders have particle sizes of the order of 10 to 40 microns. Fibrous binders include polymeric fibers such as polyolefins, which are derived from monomers having from two to about five carbon atoms, for example polyethylene and polypropylene and multicomponent fibers of various polymer geometries and combinations. The length of these types of fibers is usually less than 0.5 inches. The preferred length is less than 0.25 inches. The preferred fiber diameter is less than 200 microns.

P1131 / 99MX Additional thermoplastic polymers such as ethylene-vinyl acetate, polystyrene, polyvinyl chloride, polycarbonates, polysulfones, polyesters and nylons can be used as binders. Crystalline polymers usually give better physical strength and better defined melting temperatures. Amorphous polymers do not have melting temperatures; The best way to select the baking temperature is to experiment between 5 and 202C above vitreous transition temperature. The melting and glass transition temperatures can be determined using DSC (Differential Scanning Calorimetry) or can be obtained from the suppliers. In addition to the aforementioned components, the porous structures of the present invention may also include optional components or additives such as cationic charged resins, ion exchange materials, perlite, diatomaceous earth, activated alumina, zeolites, resin solutions, latex, materials and fibers. metals, cellulose, coal particles, carbon fibers, rayon fibers, nylon fibers, polypropylene fibers, polyester fibers, glass fibers, steel fibers and graphite fibers and the like, including mixtures thereof to provide properties and particularities P1131 / 99MX additional or to decrease the cost of the product. Many fibers such as polypropylene, polyester, nylon, glass, carbon, steel and graphite are good candidates for improving resistance to stress and impact. The amounts of these optional components vary between about 0.1 and 90 weight percent, with a concomitant decrease in the amount of the primary medium. Although several of the optional components can also serve as a primary separation medium or green strength agents and thus be present in the mixtures from which the porous structures are produced, as optional components they are employed whereby the separation means or the green strength agents used are not the same as, for example, where the separation medium is diatomaceous earth and the optional component is carbon fiber or the green strength agent is a polyolefin fiber and the optional component is a fiber of glass. The cationic charged resins can be sprayed directly on the particulate medium, such as diatomaceous earth and carbon. These treated media will adsorb small anionic particulates with greater efficiency in aqueous separation or filtration. Those resins have been P1131 / 99MX described in previous patents owned by the Assignee of the registry, whose subjects are considered part of the present, as reference. These include, for example, U.S. Patent Nos. 4,007,113 and 4,007,114 related to a medium modified with cationic formaldehyde melamine colloid; No. 4,305,782 related to modified fibrous and particulate elements of cationic colloidal silica and N2 4,309,247 related to a fiber and cellulose particulate medium treated with epichlorohydrin-polyane resin and cationic polyamide. The preferred process for the practice of the invention is the dry laying of the components, as opposed to wet laying or wet processing. In the dry laying process, the components are first mixed dry, followed by the distribution of the mixture on a suitable surface at room temperature. The definition of "suitable surface" in the sense in which it is used herein includes deposit in a-mold as well as on another surface that allows to build or form a desired thickness of the dry mix for further processing. When the mixture is deposited in a mold, the desired thickness is obtained essentially when filling the mold. As will be explained later, the mixture also P1131 / 99MX can be distributed on a flat surface, up to a uniform and convenient thickness. Accordingly, the practice of the process of this invention is not limited by the use or not of a mold. The definition of "dry" includes minimal amounts of liquid within the mixture. This amount of liquid does not significantly change the appearance and the physical handling to turn it into a process or mixed in "wet", which is defined as having dripping liquid or that requires different handling. Thus the process of the present invention does not include the formation of a wet pulp of the components; therefore, it is not necessary to apply vacuum or other steps for liquid removal. The particle size distribution of the mixture can be kept very uniform by the presence of a fibrillated fiber component throughout the entire structure. In other words, fibrillated fibers prevent the separation or migration of large and small particles. The mixture in this stage has no resistance in green. The next step in the process of the present invention is the densification in different ways and forms of the dry-laid mixture. These methods include calendering, pressing, plunger molding, P1131 / 99MX injection molding, isostatic pressing and extrusion. Where the mixture has been deposited in a mold, it is compressed and densified by plunger molding, isostatic compression and the like. In the same way, where the mixture has been distributed to a flat surface, it can be compressed and densified by calendering or other pressing operations, forming a flat sheet which can be used if a flat sheet medium is desired or can be cut from from those sheets, disc-shaped units for final use in appropriately configured porous structures. Isostatic compression includes either wet bag or dry bag processing. As is known, both methods employ a chamber that is filled with fluid which is applied with hydraulic pressure simultaneously and uniformly to all the surfaces of the part to be formed. The pulverized material to be compacted is encapsulated in a shaped membrane, known as "bagged machining", which serves as both a mold for the part and a barrier against the hydraulic fluid. Uniform pressure compacts dust from all directions to the exact form of bagging. In the wet bag method, the powder is loaded in a rubber mold. After loading, the mold will P1131 / 99MX seals and hydraulic pressure is applied. Once the pressurization is complete, the mold must be reopened and the compressed part removed. In the method of dry bag machining, the hydraulic pressurizing fluid is sealed with a master dry bag inside the pressure chamber and it is inside this master bag that a dry-bag machining is inserted separately. With this method the material is loaded into the bagged machine and after pressurization, it can be removed from the pressure chamber. The bag-dry method simplifies operations and increases production speed. Bag-dry compression is a preferred means, although not exclusively, to provide the step of densification. With reference to Figure IA, the dry-spread mixture of the components forming the porous structure 20 is fed into a rubber mold, bag 21, held within a pressure vessel 22. The container 22 provides a hydraulically activated chamber. 23 to compress the mold 21. In Figure IB, the container is closed with a lid 24, through the appropriate means (not shown) and the mold 21 is then compressed inside the chamber 23 (Figure 1C). After compression the product in P1131 / 99MX green 25, has sufficient green strength to be self-sustaining without an external mold and as described in Figure ID, the pressure of the bag 21 is released, the container 22 is opened and the product 25 is removed by the suitable means, such as a ram 26. The filling of the rubber bag is carried out with the aid of a hopper or similar filling apparatus, described in general with the number 28. This apparatus must be capable of distributing in a manner uniform the mixture of components 20 inside the mold quickly and in measured quantities. Being an apparatus that is part of the usual technique, it need not be described in more detail. Of course, the aforementioned explanations as well as Figures 1A-1D are only schematic and have been simplified for the presentation of a type of operation. As noted above, the dry-laid mixture of the components forming the porous structure 20 can also be deposited on a flat surface. Alternatively and with reference to Figure 2A, that planar surface 30 may consist of a moving band, suitably supported passing through a calendering apparatus, generally 31. The mixture is first deposited to provide the proper thickness , in the way that P1131 / 99MX describes to the left of the calender in Figure 2A; it is then transported between the opposite rollers of the calender 32 and 33 to form a densified sheet of green product 34. In this step, the sheet 34 is removed from the first surface 30 and transferred to a press 35, provided with a platen lower support 36 and a top die plate 38, as schematically described in Figure 2B. The latter provides a plurality of dies 39 that stamp or cut an analogous plurality of smaller green products of porous medium, such as discs or other suitably shaped means. The green discs 34 are then transported to an oven 40 for further processing and converting them into porous media. Although a continuous process has been schematically described in Figures 2A and 2B, it is appreciated that the surface 30 could also be the lower stage of a press. The calender 31 could be replaced by an upper platen (not shown) that could compress and densify the mixture of components 20 to convert it into the green product sheet 34. Of course, the subsequent cutting of the product in green is dictated by the shape and final dimensions of the desired porous medium and therefore, the sheet itself can be configured for use in plate and frame apparatus or the like without P1131 / 99 X undergo the cutting operation described in Figure 2B. After the formation of the green product 25 or 34, the next step is to join the primary medium by melting the binder within the porous structure at a temperature just above the melting point of the polymeric binder in such a way as to maintain the condition of self support This is again described schematically in Figure 2C for the green disc products 34. The preferred temperature is up to 202C above the melting point of the binder and the most preferred is up to 10 eC above this point of fusion. For example, the temperature and the agglutination time for the high density polyethylene binders FA700 (Quantum USI) and 13040F (MiniFiber) is approximately 140 aC (~ 52C above the melting temperature and -15 aC above the softening temperature Vicat) for 40 minutes respectively. (The melting point of the binder is determined with a differential scanning calorimeter at 52C / min). At this heating temperature, the porous structure gives the highest physical strength without causing a problem of high melting flow, which is believed to reduce capacity and efficiency by plugging the pores of the separation medium P1131 / 99MX primary adsorbent, like activated carbon. In addition to the above features, the porous structures are self-sustaining during the heating process. Green strength agents also provide porous structures with hot strength. The best combinations of time and temperature depend on the type of binder mixtures. The best condition is to provide the lowest melting flow and the highest physical strength within the shortest period of time. Other thermal agglutination processes such as microwaves, radio frequency and infrared heating can be used. Unlike the existing technique, there is no cutting force applied to the medium during the baking step. Polymeric binders of ultra high molecular weight are not used. Although heating the product green enough to melt or react the binder is a preferred step, the present invention also includes a process in which the product is finished after the compression step and does not require separate baking or heating . Examples of those products produced solely by compression are presented below in Examples Nos. 1 to 20. In Table I below, the following are listed.

P1131 / 99MX differences between the processes taught by the three patents outlined in the Background and the process of the present invention which has been assigned to Cuno, Inc. None of the first three products of the prior art were self-sustaining before and during the thermal bonding P1131 / 99MX TABLE I or Multiple layers of separation media can be made with the calendering, pressing or isostatic compression processes. Mixtures of each layer can be added and pressed sequentially to make the multi-layer porous structures in various pressing conditions. In the case of the isostatic process, the mixtures of the different layers can be added simultaneously through a feeder equipped with a concentric mouth. The feeder moves upwards during filling without altering the different layers. Or, the filling process can be carried out by removing the shirts after the different components have been added. The addition of as little as about 1% of high strength fibrous materials can significantly improve physical strength and impact resistance. This type of composite structure reduces the cracking of products during shipping and handling and improves the reliability of the product. Many fibers such as polypropylene, polyester, glass, carbon and graphite are good candidates for that purpose. If the medium becomes too fluffy and difficult to process when large amounts of the fibrous materials are used in the product, it is preferable to precompact it. The shape of the P1131 / 99MX precompacted materials can be pressed in many forms such as sheets, bars, tubes, pellets and briquettes. Another advantage of the isostatic compression process is to make various shapes or patterns of the porous structure. In particular, different shapes of grooves can be molded directly on the surface of the porous structures when machining in a bag is designed with the opposite patterns. The surface grooves improve the ability to retain dirt in separation applications. In addition, this process can make porous structures, typically in a cylindrical shape, with a hollow central core that can be sealed at one end when a shorter center bolt is used. This kind of product eliminates the materials and processes that are needed to put a final cap on the end of the structure in a typical cylindrical filter construction process. Densifying by means of isostatic compression provides as another benefit the formation of porous structures that have L / D (length to diameter) ratios greater than 3: 1, in contrast to conventional means of axial compression which for practical purposes are limited to L / D from 2 to 3: 1, because of the axial density gradients that are created within the structure.

P1131 / 99MX In summary, the main ingredients within the formulations of the porous structures are: 1) primary medium (PM); 2) green resistance agent (GSA); 3) binders (B) and 4) optional additives. Optional additives usually do not change the main functions of PM, GSA and B. However, the additive may become part of PM, GSA and / or B when the additive contribution is significant. Before proceeding. With the examples to demonstrate the practice of the present invention, it is necessary to recapitulate the aforementioned components. Therefore, in some cases at least three separate components are present, excluding the optional components. These include the primary medium PM, the green strength agent GSA and the binder B, as described in boxes 50 of Figures 3A and 3B. These components are initially mixed dry, and then compressed, box 51, removed from box 52 and heated to box 53 or not heated, as described in Figure 3B. The two processes produce porous non-adsorbent and adsorbent structures, for example, filters or separation media, boxes 54 and 55 respectively of Figure 3A and boxes 56 and 58 respectively of Figure 3B.

P1131 / 99MX Focusing on the method outlined in Figure 3A and referring to Figure 4, the primary medium in box 60 may include both powders 61 and fibers 62. The binder materials in box 63 may also include both powders 64 and fibers 65. Finally, the green strength agents in box 66 can also include powders 67 and fibers 68. In the interest of simplifying explanations at this stage, species of components that are not powders or fibers, such as resin solutions , latex and water, have not been described in Figure 4, understanding that their presence is not necessarily excluded. The point to consider in Figure 4 is that the finished product 69 can be derived from the combination of powders and fibers, for example: PM powder, 61; B powder, 64 and GSA in fibers, 68 as well as mixtures of three fibers: PM, 62; B, 65 and GSA 68 and so on. It should also be considered that PM powders and fibers in general do not melt, but can be selected from meltable materials. Similarly, while B powders and fibers are meltable, powdered GSAs and fibers generally do not melt, but can be selected from meltable materials. In addition, it is not always necessary to select three separate component materials to provide a PM, B and GSA. For example, P1131 / 99MX The fiber selected for the PM can be used as the GSA for a two-component product 69 or if the fiber selected for the PM is a multi-component fiber (HDPE / PP), this can be used as the B and GSA , for a product of a component 69 and so on. Similarly, the present invention can be practiced with mixtures of more than one MW and / or more than one B and / or more than one GSA and thus, it is understood that the porous structures 69 and processes of the present invention are not limited to the combination of a single PM component, a single B component and a single GSA component. However, the porous structures of the present invention will comprise between 70 and 90 weight percent of PM; between eight and 20 weight percent of B; and between one and 15 weight percent of GSA even if two or three of the components are originally provided in the mixture by one component. If either B or GSA is a resin solution or the like, not described in Figure 4, it is still possible to select powders and / or fibers for the PM and for at least one of the other components, B or GSA. Referring next to Figures 5-7, another explanation of the invention is schematically described for three examples of mixtures of P1131 / 99MX components. In Figure 5A, the mixture of PM is indicated with 80; B is indicated with 81; and GSA, is indicated with 82. In Figure 5B, after the mixture has been compressed and heated, it will be observed that the product 83, of which only one segment is shown contains identifiable PM 80 and GSA 82, while the material binder 81 has melted and retained the other two components together, to form the product 83. A typical example (Example 41) includes carbon particles such as PM; fibrillated polypropylene fiber as GSA and polyethylene powder as B. After thermal bonding, the polypropylene fiber acts to increase the structural strength of the porous product 83. In Figure 6A, the mixture consists of PM which is indicated with 90 and a second component 91, which represents a fibrous component, which serves as GSA and B. In Figure 6B, after the mixture has been compressed and heated, it will be observed that a portion of the fiber 91 has melted, forming the binder 92 for binding the remaining fibers (GSA) and PM together in the product 93. A typical example includes carbon black as the PM and a fibrillated fiber eg PE, as GSA and B (examples 17 to 20). Figure 6C shows the complete fusion of the fiber 91, so that the primary medium 90 and the binder 92 remain. Depending P1131 / 99MX of the selected components, the product 93 can be the one described in either Figure 6B or Figure 6C. In Figure 7A, the blend comprises only one fiber, such as HDPE / PP multicomponent fibers, which are indicated with the number 91. These fibers provide PM, GSA and B (example 47). In Figure 7B after these fibers have been compressed and heated, a portion of the fibers has melted, forming the binder 92 of the product 94, while most of the fibers are now PM 95, which form the network of the fibrous matrix of the product 94. A typical example is a product that is derived from the compression and heating of multicomponent fibers, such as HDPE / PP. These fibers are described in Figures 8 and 9 in which inner core 96 is PP and outer sheath 98 is HDPE. In Figure 9, after these fibers 91 have been heated, the portions of the pods 98 are fused together to form a matrix of bonded fibers that provide both separation ability and green strength. Now referring to Figures 10-13, several of the types of products that can be manufactured according to the present invention are described. In Figure 10 the product 100 comprises an element or body P1131 / 99MX cylindrical 101 with a hollow core 102. A plurality of annular grooves 103 are formed in the outermost surface 104 to increase the effective surface area of the element. Preferably, the slots are provided with opposed inclined zones 105, as described in Figures 10 and 11, which reinforce the respective slots and ensure clean separation of the mold 21 from the element 101. Although these annular slots 103 can be machined In a blank cylindrical cartridge, this extra step and the resulting waste material are removed by compressing the components in a mold, as described above. As another advantage, it is also possible to provide other outer surfaces apart from the circumferential grooves. As an example, Figure 12 describes another product 110, which provides a cylindrical body 111, with a hollow central core 112. The outermost surface 113 carries a plurality of longitudinal grooves 114, which run axially over most of the length of the body. body. Typically, the slots terminate at each end 115 of the cartridge. As another example of exterior configuration, Figure 13 describes a product 120 having a cylindrical body 121, a hollow central core 122 and is provided with a plurality of truncated dimples.

P1131 / 99MX internally 123 of the outer circumferential surface 124. Of course, it is understood that the other outer configurations are easily possible as well as the fact that the overall configuration of the product is not limited to the cylindrical, but could also be rectangular, square or otherwise configured to adapt the internal volume of a specific housing. Accordingly, it is understood that the present invention includes products having discontinuous exterior surfaces, provided without separate machining subsequent to manufacture, as well as smooth exterior surfaces, i.e., uninterrupted cylindrical or other surfaces provided by a relatively mold surface. smooth It is also possible to formulate tubular products, which have a hollow core, which are closed at one end, by densifying the mixture of components in a closed end mold. This structure is described in Figure 14 for the porous product 125, which has a cylindrical body 126, a core 128 and a closed base 129. Typically, hollow tubular products of this type, prepared from the primary reinforcing means and a Binder are hollow cylinders, open at both ends. By using the process of this P1131 / 99MX invention, these limitations no longer exist. It is also possible to prepare multilayer cylindrical porous structures according to the present invention. With reference to Figure 15, a pressure vessel 130, provided with a rubber mold, bag 131, placed inside a hydraulically activated chamber 132, is described. The chamber 132 is closed at the base by a ram 133 and at the top by a removable lid (not shown) that is received within the opening of the mold 134. Placed inside the rubber mold are a plurality of cylindrical sleeves, for example, two 135 and 136, as well as a central cylindrical mandrel 138 which forms a hollow core 139, for the porous structure 140 (Figure 16). Although the use of a mandrel is not critical to manufacture of the porous structures because the process of the present invention is suitable for the manufacture of solid porous structures, a mandrel will be used to make hollow structures which are, in turn, employed if want or need radial flow through the porous structure. As is evident from Figure 15, the shirts 135 and 136 are concentric with the mandrel 138 and together leave a margin for the addition of three different combinations of components 141, 142 and 143.

P1131 / 99MX The liners are initially placed inside the rubber mold 131 in such a way that three cylindrical layers of components can be formed after which the liners are removed, the mold is closed and the components densified under pressure. The mold is subsequently opened and the green product 140 is removed by the ram 133 for later heating and melting the binder materials. With reference to Figure 16, a portion of the resulting product 140 having an outer layer 141 of a type of medium is described; an intermediate layer 142 of another type of medium and an inner layer 143 of a medium different from that of the intermediate layer 142, which may be the same medium as that of the outer layer 141 or different. The advantages should be evident considering the fact that the resulting product 140 can provide variable or gradient porosities, from coarse to fine or from coarse to fine. In addition, different types of primary media can be used, such as particulate and fiber, which is true for the other two components, the binder material and the green strength agent. Furthermore, although the above description refers to three distinguishable layers, it will be understood that multi-layer products that provide two or more layers of the three P1131 / 99MX layers are possible according to the present invention. As an alternative, it is also possible to prepare multilayer cylindrical porous structures without the use of jackets. With reference to Figure 17A, a pressure vessel 130, provided with a rubber mold, bag 131, placed inside a hydraulically activated chamber 132 is again described. The chamber 132 is closed at the base by a ram 133 and in FIG. the upper part with a removable lid 145 (Figure 17C) which is received within the opening of the mold 135. When the mold is opened, a filling apparatus, filler 146 is inserted, which supplies concentric layers of the composite medium as described through this. The filler 146, in the manner described, provides an open base 148 and a funnel-like upper mouth 149. The filler 146 is supplied with a source of composite blends according to the present invention, in this example with two. It is understood that the filler 146 has been described somewhat schematically with the interest of simplification and that the means for supplying the compound mixtures to the mouth and through the filler are within the scope of the art and need not be described. The filler 146 also provides an outer wall 150 and an inner sleeve P1131 / 99MX 151, to provide two separate concentric layers, 152 and 153, of composite mixtures. Of course, although only two layers are shown, it is understood that more layers are possible. The filler 146 is initially placed within the bottom of the mold, as described in Figure 17 and the mixtures are carefully deposited within the mold in such a way that the layers 152, 153 remain separate and distinct. A, as it is slowly removed, (Figure 17B) the composition continues to flow into the mold and forms in essence, a layered pre-product, prior to densification. When the filler 146 has finished the deposit, the flow is interrupted (by suitable means, not shown), this is removed and the lid 145 is placed, after which the blends are subjected to isostatic compression. After pressing, the product 155 appears as in Figure 17C and is removed from the mold 130, similar to the procedure described above. Again, while a mandrel 138 has been described for a hollow structure, solid, layered structures can be manufactured by omitting the mandrel. It is understood that one could also form products of multiple layers with two or more zones of layers of different character when compressing sequentially P1131 / 99MX a layer added on a cylindrical or other previously made structure. Although this embodiment has not been described in the drawings, based on the above-described description herein, it is within the scope of the art to form a porous structure in this manner and consequently is an alternative included within the scope of this invention. Sequential compression can be performed by adding a layer or layers of composite materials to the compressed structure 155, before it has been removed from the mold or after which the structure could be placed in another apparatus or returned to the mold. In addition, flat sheets or layered materials may also be formed, particularly, when the mixture of components is calendered or otherwise densified to provide those shapes. On the other hand, it is possible to formulate products in two-layer and multi-layer flat sheets by adding consecutive layers of mixtures of components on the first layer. In this way, it is possible to make from different mixtures of the basic components, each layer with a specific mixture of one or more of the component elements to provide primary separation, reinforcement and agglutination capabilities. The specific mixture can be the same as that of another layer in the P1131 / 99 X product or different. Also, these layers may have smooth exterior, for example, the upper and lower surfaces or may be provided with slots or other configurations, similar to those described above. With reference to Figure 18, an apparatus 160 comprising a moving band 161, which provides a flat surface 162, is schematically described, the band is driven by a motor 163. Above the surface 162, there is a first hopper 164 which supplies a first type of medium 165, which extends uniformly by a doctor blade or roller 166. A second hopper 168 is provided downstream of the first to supply an intermediate layer of medium 169, which again extends from uniformly by means of a roller 166. Below, there is a third hopper 170 which supplies a third type of medium 171, which also extends uniformly by means of a roller 166. As a result, a product that can be densified on the surface is formed. band by means which are not shown to form the product in green 172 or may be densified subsequently. In Figure 19, a portion of the multi-layer flat product 175 in section is described Transverse P1131 / 99MX, which provides a first layer 165 of a type of medium; an intermediate layer 169 of another type of medium and a third layer 171 of a medium different from that of the intermediate layer 169, which may be the same medium as that of the first layer 165 or different. As for the layered cylindrical product 140, the resulting product 175 can provide variable or gradient porosities, from coarse to fine or from coarse to fine. In addition, different types of primary media, binder material and / or green strength agents can be used. Again, while the aforementioned description refers to three distinguishable layers, it is understood that multi-layer products that provide two layers or more than three layers are possible according to the present invention. Similar to the explanation provided with respect to Figures 2B and 2C, the flat sheet green product 172 can be punched into a plurality of disks or other shaped means. Again it is understood that one can also form multi-layered products with two or more zones or layers of different character by sequentially compressing an additional layer on a flat structure previously made. Doing so would simply require the step of feeding a back layer of another medium P1131 / 99MX compound, before heating, followed by densification of all layers. Additional layers could be added in this way or several layers of the medium could be added and densified in one step, depending on the design of the apparatus used. From the aforementioned explanation of the fibrous components, it is understood that the fibers can be monofilaments, as represented by fiber 180 in Figure 20 or can be fibrillated, as represented by fiber 181 in Figure 21. fibrillated fibers 181 provide fibrils 182 that extend outwardly from strands 183. Fibrillated fibers are useful as PM, as GSA and as binder B, when some fusion occurs. According to the preferred process of the present invention, a variety of porous structures can be manufactured under various different pressing and heating conditions based on whether the primary medium is non-adsorbent or adsorbent (or absorbent). The various combinations for manufacturing are shown diagrammatically in Figures 3A and 3B. There are nine (9) main cases to make porous non-adsorbent structures and four (4) main cases to make porous structures P1131 / 99MX adsorbents presented in Table II when compressed and heated different combinations of material PM, GSA and B.

TABLE II CASES FOR COMPRESSION AND COMPONENT HEATING The symbol 0 indicates the presence of the ingredient and it does not work as a binder. The symbol M indicates the presence of the ingredient and it melts and reacts as a binder. Case Al: The primary means and the agent of P1131 / 99MX green resistance do not melt or react. Only the binder melts or reacts. (Example 41). Case A2: The primary medium does not melt or react. Both the green strength agent and the binder melt or react. (Examples 21-23). Case A3: The green resistance agent does not melt. The primary medium and the binder both melt or react. (Example 42). Case A4: The primary medium, the green resistance agent and the binder, all melt. (Example 43). Case A5: Either the primary or the binder function as a resistance agent in green. Only the binder melts or reacts. (Example 44). Case A6: the green resistance agent melts or reacts. No binder is needed. (Examples 17-20, if the PE melts). Case A7: Both the primary medium and the green resistance agent melt or react. (Example 45). Case A8: The primary medium melts or reacts. No binder is needed. (Example 46). Case A9: The primary medium acts as a resistance agent in green and as a binder. (Example 47).

P1131 / 99MX In another example, multi-component polyethylene sheath fiber / polypropylene core can be used as the primary medium, however, if the polyethylene sheath melts on heating, then it functions as a binder. If the binder is not present, either the PM and / or the GSA must melt or react (Case Aβ, A7, A8 and A9). Formulations with more than one class of PM, GSA and B are covered by the combinations of the nine basic cases that are "shown in Table 2. In the case of porous adsorbent structures, the primary medium does not melt or react with others. ingredients, therefore, only four (4) different cases can be found for the different combinations (Table II) .The porous adsorbent structures, for example, activated carbon medium, must be made with the minimum amount of binder to reduce the obstruction However, non-adsorbent media does not have these restrictions, Normally, it is preferred to have greater physical strength at high flow rates.The amount of binders for non-adsorbent media can be significantly greater than the amount used for the media. Adsorbent media, if greater physical resistance is required P1131 / 99MX If the medium does not require bond strength when melting oh When reacting the binder, the green strength agent is then required to have the porous structure bonded to give the final strength. The primary medium (PM) and / or the green resistance agent (GSA) must be responsible for contributing to the resistance. The porous structure is held together by fibers and particles that become entangled or deformed. For each of the non-adsorbent and adsorbent media there are two (2) cases listed in Table III. Typical fine metal fibers and particles are ideal candidates for providing physical strength.

TABLE III CASES FOR FORMULATION WITHOUT AGGLUTINANT The symbol O indicates the presence of the ingredient and it does not work as a binder.

P1131 / 99MX To demonstrate the practice of the present invention, a series of filter blocks were prepared in the manner detailed below in the examples. All parts are presented in percentage weight, unless otherwise indicated.

EXAMPLES NO. 1-20 The contribution of fibrillated fiber, ie polyethylene (PE), on the green strength of the carbon block was demonstrated by formulating carbon, PE fiber and PE powder using the following ingredients: 85% Coal: Barnebey & Sutcliffe Coal Type 3049, 80x325 mesh 4-15% PE fiber: (Minifiber, 13040F) 5-11% PE powder: (Quantum Chemical, FASP007) As will be seen, the relative amounts of powder and fiber, totaling 15 percent polyethylene (PE) by weight, were varied between Examples 1 to 20. All the blocks that were made were 55 grams and each It was molded into blocks with a metal piston mold at various pressures. The mold used was 1.75 inches of O.D. (external diameter) and 0.375 inches of I.D. (internal diameter) and the pressure time was 15 seconds. The length varied slightly between approximately 2 and 5 percent, P1131 / 99MX depending on the molding pressure and was approximately 2.4 inches. The resistance in green was measured by compressing the porous structures perpendicular to the axis of the block at a speed of 0.0238 inches / sec. The effects of molding pressure and the amount of PE fiber on green strength are given in Table IV and Figure 22. The four curves in Figure 22 are graphs of the data presented in Table IV, each curve starts at 4 percent PE fiber and increases up to 15 percent. The respective green resistances can be read and compared from the curves.

P1131 / 99MX TABLE IV EFFECT OF MOLDING PRESSURE AND FIBER PE CONTENT ON GREEN RESISTANCE P1131 / 99MX As is evident from Table IV, the higher molding pressures provide greater green strength and these were higher when the PE fiber was increased, for blocks containing 85 percent carbon. For post-processing purposes, the acceptable green strength for these blocks is approximately 20 pounds. Examples 21-24 Three porous structures (carbon blocks) were made using the following ingredients: 4% PE fiber 13040F 11% PE powder FASP007 85% Coal: Barnebey & Sutcliffe coal type 3049, 80x325 mesh A mold of the same size as that used for Examples No. 1-20 was used, the molding force was 8000 psi and the pressure time was 15 seconds to produce blocks of 2.25 inches in length except in Example 24 where it was a 9.75 inch block manufactured by KX Corporation that was subsequently cut into 2.25 inch blocks. The KX Corporation block contained 85 percent carbon and 15 percent binder. A collapse test was performed on fractions of 0.625 inches, P1131 / 99MX cut from the 2.25 inch blocks, compressing at a speed of 0.0238 inches / sec. The blocks were 1.75 inches from O.D. (external diameter) and 0.375 of I.D. (internal diameter) . Examples 21-23 were baked at 139 BC during the period mentioned in Table V. Methylene chloride reduction evaluations were conducted to evaluate the efficiency of the various blocks. To a stream with 300 ml / min feed flow of municipal water from Meridien, Connecticut, methylene chloride was injected at a concentration of 300 ppb. The interruption concentration was set at 15 ppb. After the experiment, the collapse tests were performed in fractions of 0.625 inches, cut from the 2.25-inch blocks, compressed perpendicular to the axis at a speed of 0.0238 inches / sec. The results of both tests are presented in Table V.

P1131 / 99MX TABLE V REDUCTION OF METHYLENE CHLORIDE IN CARBON BLOCK AND PROOF OF COLLAPSE Examples N2. 25-29 The same formulation that was used for Examples 21-23 was scaled to make blocks of 290 grams, 12 inches long with O.D. of 1.75 inches and 0.375 of I.D. The isostatic compression process was employed according to the preferred embodiment, using a rubber mold and compression by hydraulic pressure at 2500 psi for 20 seconds. The blocks were subsequently baked at different times between 1422C and 1432C and then cut into 9.75 inch lengths to be tested. Fine test powder (ACFTD) was used for the three tests: gram life; P1131 / 99MX turbidity reduction efficiency and percentage of particulate reduction at 0.6GPM. Two 9.75-inch products from KX Corporation were evaluated from different batches (Examples No. 28 and 29). Collational force tests were also performed and reported in Table VI, with the other results of the test. The definitions of the terms used in Table VI are the following: a. ? P; Differential pressure (psid) through the filter at a flow rate of 0.6 GPM. b. Gram life, ACFTD: The cumulative weight (in grams) of the AC fine test powder (ACFTD) fed to the filter when the differential pressure increased by 20 psi at a flow rate of 0.6 GPM. c. Turbidity, NTU: Nephelometric turbidity units. Turbidity is a function of the concentration and particle size of suspended solids in water. d. Percentage reduction of the number of particles between l-5μm. The NSF (National Sanitation Foundation) Standard 42 is using a minimum of 85% reduction in this particle range to classify particulate reduction as Class II.

P1131 / 99MX TABLE VI ACFTD CARBON BLOCK AND COLLAPSE TEST Example 30-33 Four porous structures (carbon blocks) were made using the following ingredients shown in Table VII. The length was approximately 2.42 inches, the O.D. It was 1.75 inches and the D.I. It was 0.375 inches. The blocks were molded with a force of 6000 Ib and baked at 1412C for 45 minutes. The radial air flow resistance was measured at a constant flow of air at a rate of 135 SCFH through a fraction of 0.625 inches of filter donuts. In these examples, both the PE fiber and the powder melt as binder materials and the reinforcing effect of the PP fiber can be observed by comparing Examples Nos. 31 to 33 (1 to 3% fiber) with the No 30 which does not contain fiber, namely approximately 50 to 60 percent increase in the strength of the final product, as indicated by the collapse force test.

P1131 / 99MX TABLE VII EXAMPLES AND PROPERTIES OF CARBON BLOCKS Example No. 34 A 55 gram block was made in a 2.4 inch OD, 0.75 inch ID metal mold, using a 2000 Ib molding force and the following ingredients: 85% diatomaceous earth (Grefco, Dicalite 6000) 6 % PE fiber 13040F 9% PE powder FASP007 The block was baked at 1422C for 45 minutes.

Example No. 35 The formulation and the mold specifications of Example 34 were repeated for Example 35 except that 2.00 grams of Kymene 557H resin (Hercules, 12.5 percent solids) was added. The porous structure was baked at 1422C for 45 minutes.

Example No. 36 A 55 gram block was made in a 2.40 inch metal mold. OD, 0.75 inches ID, using a molding force of 2000 Ib and the following ingredients: 80% Diatomaceous earth (Grefco, Dicalite 6000) 5% Polypropylene fiber (PP) (MiniFiber Y600F) 6% Fiber PE 13040F 9% Powder PE FASP007 The block was baked at 1422C for 45 minutes.

P1131 / 99MX Example No. 37 A 55 gram block was manufactured in a 2.40 inch OD, 0.75 inch ID metal mold, using a molding force of 6000 Ib and the following ingredients: 65% Coal type 3049 4% Fiber PE 13040F 11% PE FASP007 powder 20% Diatomaceous earth (Grefco, Dicalite 6000) The block was baked at 1422C for 45 minutes.

Example No. 38 A 55 gram block was manufactured in a 2.40 inch OD metal mold, 0.75 inches ID, using a 5000 Ib molding force and the following ingredients: 85% Cuno MicroKlean milled powder composed of cured resinous binder and cellulose fiber, sieved in mesh 120-400 8% Fiber PE 13040F 7% PE FASP007 Powder The block was baked at 1432C for 50 minutes.

Example No. 39 A porous structure of 20 grams was made in a metal mold of 2.40 inches of O.D., 0.75.

P1131 / 99MX ID inches, using a molding force of 4000 Ib and the following ingredients: 23.5% Polypropylene fiber (Hercules, type T-153, 3 denier, 3 mm) 15.5% Fiber PE 13040F 1.5% Powder PE FA700 ( Quantum) 59.5% Coal type 3049 The porous structure baked at 1402C for 50 minutes.

Example No. 40 A porous structure of 15 grams was made in a metal mold of 2.40 inches OD, 0.75 inches ID, using a molding force of 6000 Ib and the following ingredients: 6.25% Powder PE FA700 31.25% Fiber PE 13040F 62.5% Polypropylene Fiber (Microfibers, NAT) The porous structure was baked at 141 SC for 45 minutes.

Example No. 41 A 55 gram porous structure was fabricated in a 2.40 inch OD metal mold, 0.75 inches ID, using a molding force of 6000 Ib and the following ingredients: 80% Coal type 3049 8% Fiber PP ( MiniFiber Y600F) P1131 / 99MX 12% Powder PE FA700 The porous structure was baked at 1412C for 45 minutes.

Example No. 42 A porous structure of 20 grams was made in a metal mold of 2.40 inches of OD, 0.75 inches of I.D., using a casting force of 6000 Ib and the following ingredients: 50% HDPE sheath multi-component fiber / PP core (BASF, B1657) 30% PP Fiber (MiniFiber, Y600F) 20% PE FA700 Powder The porous structure was baked at 1412C for 45 minutes.

Example No. 43 A porous structure of 20 grams was made in a metal mold of 2.40 inches of OD, 0.75 inches of I.D., using a molding force of 6000 Ib and the following ingredients: 65% Multi-component fiber HDPE sheath / PP core (BASF, B1657) 25% Fiber PE 13040F 10% Powder PE FA700 The porous structure was baked at 141 SC for 45 minutes.

P1131 / 99MX Example No. 44 A porous structure of 15 grams was made > in a 2.40 inch OD metal mold, 0.75 inches ID, using a 2000 Ib molding force and the following ingredients: 70% PP Fiber (Y600F) 30% PE FA700 Powder The porous structure was baked at 141 BC for 45 minutes Example No. 45 A porous structure of 20 grams was made in a metal mold of 2.40 inches O.D., 0.75 inches of I.D., using a molding force of 6000 Ib and the following ingredients: 85% Multi-component fiber HDPE sheath / PP core (BASF, B1657) 15% Fiber PE 13040F The porous structure baked at 141 C for 45 minutes.

Example No. 46 A porous structure of 20 grams was made in a metal mold of 2.40 inches O.D., 0.75 inches of I.D., using a molding force of 6000 Ib and the following ingredients: 80% Multi-component fiber HDPE sheath / PP core (BASF, B1657) P1131 / 99MX 20% Polypropylene Fiber Y600F (MiniFiber) The porous structure was baked at 141 aC for 45 minutes.

Example No. 47 A porous structure of 20 grams was made in a 2.40 inch OD, 0.75 inch ID metal mold, using a molding force of 6000 Ib and the following ingredients: 100% HDPE sheath multi-component fiber / PP core ( BASF, B1657) The porous structure was baked at 1412C for 45 minutes.

Example No. 48 A 55 gram porous structure was fabricated in a 2.40 inch OD, 0.75 inch ID metal mold, using a molding force of 6000 Ib and the following ingredients: 84% Coal type 3049 4% PE Fiber ( 1304F) 1% PP Fiber (MiniFiber, Y600F) 11% PE FA700 Powder The porous structure was baked at 1412C for 45 minutes.

P1131 / 99MX Example No. 49 A formulation of 66.5 g of TOGC coal (80x325 mesh) from Calgon, 28.5 g of Georgia Pacific GP 5485 phenolic resin powder and 3 g of water was mixed in an Osterizer mixer at the lowest speed by 30 seconds. Then, 13 g of the mixture was molded into a block of 1.75 inches of D.O., 0.375 inches of I.D., 7/16 of an inch thick and baked at 1302C for 2 hours.

Example No. 50 55 g filters were manufactured in a donut shape in a 2.40 inch metal mold of O.D. and 0.75 inches ID, using a 4000 Ib molding force and the following ingredients: 60% Cuno MicroKlean milled powder composed of cured resinous binder and cellulosic fiber, sieved through 200 mesh 39.6% BTL melamine-formaldehyde resin powder , grade 412 0.4% citric acid (solids), solution 8% The porous structure was baked at 141 aC for 45 minutes. Porous structures representing Examples No. 34 to 50 were tested against a fraction of a KX 1M carbon block and reported in Table VIII. The resistance to radial air flow was measured at P1131 / 99MX constant flow of air at a speed of 50 SCFH through a fraction of filtering donuts of 0.625 inches. The air flow resistance and collapse force that were measured for Examples 34 to 50 are presented in Table VIII.

TABLE VIII P1131 / 99MX Thus it must be evident that the process of the present invention is quite effective in the manufacture of porous structures. The invention is particularly suitable for the production of block carbon structures for example, filters, which have high weights of the separation medium (filters) and relatively low weights of binder, but which are not necessarily limited thereto. The process of the present invention can be employed with a variety of equipment and component materials. In the same way, the separation medium made according to the process need not be limited to the powder carbon medium. Nor is the shape of the porous structures a limitation of the present invention in view of the fact that flat sheets can be made; flat structures; cylindrical structures open at both ends or closed in one of them and practically any structure of geometric shape, solid and also hollow. On the other hand, the outer surfaces of the porous structures can vary greatly. Based on the foregoing discussion, it should now be evident that the use of the process described herein will comply with the objects set forth above. It is therefore understood that any apparent variation that falls within the scope of the claimed invention and thus, the selection of the specific component materials is P1131 / 99MX can do without deviating from the spirit of the invention that is set forth and described herein. In particular, the porous structures according to the present invention are not necessarily limited to those that are carbon based; nor are the blocks limited to the preferred hollow core cylindrical shapes. In the same way, the products are also included in layers, which are derived from more than one mixture of components and which provide at least two different properties or separation characteristics. In this manner, the scope of the invention will include all modifications and variations that may fall within the scope of the appended claims.

P1131 / 99MX

Claims

NOVELTY OF THE INVENTION Having described the present invention, it is considered as a novelty and, therefore, the content of the following CLAIMS is claimed as property: 1. A process for the manufacture of porous structures consisting of: forming a dry mixture which comprises a component that provides primary separation capacity, a component that provides green strength strengthening capacity and a component that provides agglutination capacity and is selected from the group consisting of thermoplastic and thermosetting polymers; distributing that mixture on a suitable surface and forming a desired thickness thereof; densify that mixture in the way that is desired for the porous structure; remove the porous structure from the surface; agglutinate the component that provides the primary separation capacity by heating the mixture to a temperature up to about 20SC above the melting point of any of the thermoplastic components that provide the agglutination capacity.
2. A process for the fabrication of porous structures, similar to the one described in P1131 / 99MX claim 1, wherein the step of forming includes the step of selecting the first, the second and the third of the components, each of the components providing one of the three capabilities.
3. A process for the manufacture of porous structures, similar to that set forth in claim 1, wherein the step of forming includes the step of selecting two of the three components, which together provide those three capabilities.
4. A process for the manufacture of porous structures, similar to that set forth in claim 1, wherein the step of forming includes the step of selecting a component that provides the primary separation capacity, the reinforcing capacity of the strength in green and the capacity of agglutination.
5. A process for the manufacture of porous structures, equal to that set forth in claim 1, wherein the steps of distributing and densifying are performed by means of compression machining.
6. A process for the manufacture of porous structures, equal to that set forth in claim 1, wherein the step of distributing includes the step of filling a mold with the mixture and the step of densifying is performed by isostatic compression of the mixture to get to the shape of the structure P1131 / 99MX porous, which has enough green resistance to be self-sustaining.
7. A process for manufacturing porous structures, similar to that set forth in claim 6, which includes the additional step of providing a mandrel in the mold prior to the filling step.
8. A process for the manufacture of porous structures, similar to that set forth in claim 7, wherein the shape of the porous structure is cylindrical and this porous structure is hollow.
9. A process for the manufacture of porous structures, similar to that set forth in claim 8, wherein the shape has an L / D ratio of at least about 3: 1.
A process for the manufacture of porous structures, equal to that set forth in claim 6, which includes the additional steps of filling the mold with at least a second dry mix of the components around the porous structure; and isostatically compressing that second mixture around the porous structure, which thereby provides a porous structure that has sufficient green strength to be self-sustaining.
11. A process for manufacturing porous structures, similar to that set forth in claim 10, wherein the additional steps are P1131 / 99MX carried out after the step of removing and that includes the additional step of returning the porous structure to the mold before the additional steps.
12. A process for manufacturing porous structures, similar to that set forth in claim 6, wherein the shape of the porous structure is cylindrical and includes the additional steps of providing a mandrel within the mold and at least one cylindrical sleeve, concentric with the mandrel, the sleeve and the mandrel define separate volumes and where the step of distributing includes the steps of filling the defined volume between the mold and the sleeve with a first dry mixture of components and filling the defined volume between the sleeve and the mandrel with a second dry mixture of components, different from the first; and removing the shirt from the mold before the step of densifying.
A process for the manufacture of porous structures, like that set forth in claim 12, which includes the additional steps of providing one or more additional cylindrical sleeves, concentric with the mandrel, these additional jackets define separate volumes and wherein the step of distributing includes the step of filling the defined volume between adjacent jackets with a second dry mixture of components; Y P1131 / 99MX remove the sleeves from the mold before the step of densifying.
A process for the manufacture of porous structures, similar to that set forth in claim 6, wherein the shape of the porous structures is cylindrical and includes the additional steps of providing a mandrel within the mold; and filling the defined volume between the mold and the mandrel with at least the first and second mixtures of dry components in concentric layers around the mandrel, before the step of densifying, the second mixture of components is different from the first.
A process for the manufacture of porous structures, similar to that set forth in claim 14, which includes the additional steps of filling the mold with at least one third dry mixture of components around the porous structure; and isostatically compressing the second mixture around the porous structure, thereby providing a porous structure in layers that has sufficient green strength to be self-sustaining.
16. A process for the manufacture of porous structures, similar to that set forth in claim 15, wherein the additional steps are carried out after the step of removing and which includes the additional step of returning the porous structure to the P1131 / 99MX mold before the additional steps.
A process for the manufacture of porous structures, similar to that set forth in claim 1, wherein the step of distributing includes the step of applying the mixture on a flat surface and the step of densifying includes the step of pressing the mixture distributed to have a sheet of reduced thickness, which has enough resistance in green to be self-sustaining.
18. A process for the manufacture of porous structures, equal to that set forth in claim 17, which includes the additional step of applying at least a second dry mixture of components on the first distributed mixture, before the step of densifying.
19. A process for the manufacture of porous structures, similar to that set forth in claim 17, which includes the additional steps of applying at least one second mixture, different from the distributed mixture, on the densified sheet and pressing the second distributed mixture and the densified sheet to have a sheet in layers of reduced thickness, which has sufficient resistance in green to be self-sustaining.
20. A process for the manufacture of porous structures, equal to that set forth in claim 19, which includes the additional step of P1131 / 99MX cut desired shapes of the porous structures from the sheet of reduced thickness.
21. A process for the manufacture of porous structures, similar to that set forth in claim 1, wherein the component providing primary separation capacity is selected from the group consisting of carbon particles, diatomaceous earth, perlite, activated alumina, silica, zeolites, natural fibers and artificial and synthetic fibers.
22. A process for the manufacture of porous structures, similar to that set forth in claim 21, wherein the natural fibers are selected from the group consisting of cellulose, wool, jute, hemp and the artificial and synthetic varieties are selected from the group which consists of fibers made of polyolefins, polyesters, carbon, graphite, glass, acrylics, scratches, nylons, aramids, multicomponent fibers and mixtures thereof.
23. A process for the manufacture of porous structures, similar to that set forth in claim 1, wherein the component that provides strength reinforcement in green is a fiber selected from the group consisting of polyolefins, polyesters, nylons, aramides, scratches and mixtures thereof and liquid green strength agents. P1131 / 99MX
24. A process for the manufacture of porous structures, similar to that set forth in claim 23, wherein the liquid green strength agents are selected from the group consisting of styrene-butadiene latex, poly (ethylene-) vinyl acetate) and acrylate; methyl cellulose and hydroxypropyl methyl cellulose, carboxymethyl cellulose, hydroxyethyl cellulose; polyvinyl alcohol; polyvinyl pyrrolidone; polyacrylic acid; polyethylene oxide; polyethyleneimine; polyacrylamide; natural gums and copolymers thereof; water and mixtures with one or more of the aforementioned liquid green strength agents.
25. A process for the manufacture of porous structures, similar to that set forth in claim 1, wherein the thermoplastic and thermosetting polymer component that provides agglutination capability is selected from the group consisting of polyolefin resins, epoxy, phenol-formaldehyde and melamine- formaldehyde powder and polyolefin fibers.
26. A process for the manufacture of porous structures, similar to that set forth in claim 1, which includes the additional step of adding an additional component selected from the group consisting of cationic charged resins, ion exchange materials, perlite, diatomaceous earth , P1131 / 99MX activated alumina, zeolites, resin solutions, latex, metallic materials and fibers, cellulose, carbon particles, carbon fibers, rayon fibers, nylon fibers, polypropylene fibers, polyester fibers, glass fibers, fibers of steel and graphite fibers, which include mixtures thereof in an amount ranging from 0.1 to about 90 weight percent, with a concomitant decrease in the amount of primary medium.
27. A process for the manufacture of porous structures, equal to that set forth in claim 1, which includes the additional step of cationically loading the additional component selected from the group consisting of perlite, diatomaceous earth, activated alumina, zeolites, cellulose, rayon fibers, nylon fibers and carbon particles.
A process for the manufacture of porous structures, similar to that set forth in claim 27, wherein the step of cationically loading the optional component is carried out before the forming step and includes the additional step of adding to the mixture the cationically charged component.
29. A process for manufacturing porous structures, similar to that set forth in claim 1, wherein the desired shape that is created P1131 / 99MX by the step of densifying the mixture is a flat layer.
30. A process for the manufacture of porous structures, similar to that set forth in claim 29, which includes the additional steps of forming at least a second mixture of the components; densify the second mixture to form a flat layer and combine the layers to form a multi-layer product.
31. Porous structures comprising: between about 70 and 90 weight percent of a component that provides primary separation capacity; between one and about 15 weight percent of a component that provides green strength strengthening capacity; and between about eight and 20 weight percent of a component that provides agglutination capacity and is selected from the group consisting of thermoplastic and thermosetting polymers.
32. Porous structures, similar to those set forth in claim 31, further comprising an additional component selected from the group consisting of cationic charged resins, ion exchange materials, perlite, diatomaceous earth, activated alumina, zeolites, resin solutions , latex, metallic materials and fibers, cellulose, coal particles, carbon fibers, rayon fibers, fibers P1131 / 99MX nylon, polypropylene fibers, polyester fibers, glass fibers, steel fibers and graphite fibers, including mixtures thereof in an amount ranging between 0.1 and 90 weight percent, with a concomitant decrease in the amount of the primary medium.
33. Porous structures, similar to those set forth in claim 31, having a first, second and third components, each component providing one of the three capabilities.
34. Porous structures, similar to those set forth in claim 31, wherein the step of forming includes the step of selecting two of the three components, which together provide the three capabilities.
35. Porous structures, similar to those set forth in claim 31, wherein one component provides the primary separation capacity, the strength capacity of the green strength and the agglutination capacity.
36. Porous structures, similar to those set forth in claim 31, wherein the component providing the primary separation capacity is selected from the group consisting of carbon particles, diatomaceous earth, perlite, activated alumina, silica, zeolites, natural fibers and artificial or synthetic fibers. P1131 / 99MX
37. Porous structures, similar to those set forth in claim 36, wherein the natural fibers are selected from the group consisting of cellulose, wool, jute, hemp and artificial and synthetic varieties are selected from the group consisting of fibers made of polyolefins, polyesters, carbon, graphite, glass, acrylics, scratches, nylons, aramids, multicomponent fibers and mixtures thereof.
38. Porous structures, similar to those set forth in claim 37, wherein the component that provides the resistance capacity in green is a fiber that is selected from the group consisting of polyolefins, polyesters, nylons, aramides, scratches and mixtures of the same and liquid green resistance agents.
39. Porous structures, similar to those set forth in claim 38, wherein the liquid green strength agents are selected from the group consisting of styrene-butadiene latex, poly. (ethylene-vinyl acetate) and acrylate; methyl cellulose and hydroxypropylmethyl cellulose, carboxymethyl cellulose, hydroxyethyl cellulose; polyvinyl alcohol; polyvinyl pyrrolidone; polyacrylic acid; polyethylene oxide; polyethyleneimine; polyacrylamide; natural gums and copolymers thereof; water and mixtures with one or more of the liquid green strength agents P1131 / 99MX mentioned above.
40. Porous structures, similar to those set forth in claim 39, wherein the thermoplastic and thermosetting polymeric component that provides the agglutination capacity is selected from the group consisting of polyolefin resin, epoxy, phenol-formaldehyde and melamine formaldehyde powders and polyolefin fibers.
41. Porous structures, similar to those set forth in claim 40, wherein the component providing the primary separation capacity consists of carbon particles; the component that provides strength reinforcement in green consists of polyolefin fibers and wherein the thermoplastic and thermosetting polymer component that provides agglutination capability consists of powdered polyolefins and only the component that provides agglutination ability is melted.
42. Porous structures, similar to those set forth in claim 40, wherein the component providing the primary separation capacity consists of carbon particles; the component that provides green strength reinforcement consists of polyolefin fibers and wherein the thermoplastic and thermosetting polymer component that provides the agglutination capacity consists of powdered polyolefins and only the two components P1131 / 99MX that provide the capacity of reinforcing the resistance in green and of agglutination melt.
43. Porous structures, similar to those set forth in claim 40, wherein the component providing the primary separation capacity consists of multicomponent fibers; the component that provides green strength reinforcement consists of polyolefin fibers and wherein the thermoplastic and thermosetting polymer component that provides agglutination capacity consists of powdered polyolefins and the two components that provide primary separation capacity and agglutination capacity are they melt
44. Porous structures, similar to those set forth in claim 40, wherein the component providing the primary separation capacity consists of multicomponent fibers; the component that provides green strength reinforcement consists of polyolefin fibers and wherein the thermoplastic and thermosetting polymer component that provides the agglutination capacity consists of polyolefin powders and the three components are melted.
45. Porous structures, similar to those set forth in claim 40, having first and second components, the first component providing the primary and secondary separation capabilities. P1131 / 99MX strengthening of the green resistance and the second component provides the agglutination capacity, wherein the first component consists of polyolefin fibers; and wherein the second component consists of powdered polyolefins and only the second component is melted.
46. Porous structures, similar to those set forth in claim 40, having first and second components, the first component provides the primary separation capacity and the second component provides the green strength and agglutination resistance strengthening capabilities wherein the first component consists of carbon particles and wherein the second component consists of polyolefin fibers and only the second component is melted.
47. Porous structures, similar to those set forth in claim 40, having a first and second component, the first component provides the primary separation and bonding capabilities and the second component provides the strength strengthening in green, in where the first component consists of a multicomponent fiber; and wherein the second component consists of polyolefin fibers and both the first and the second components melt.
48. Porous structures, equal to those that are P1131 / 99MX set forth in claim 40, having a first and second component, the first component provides the primary separation and agglutination capabilities and the second component provides the green strength reinforcement, wherein the first component comprises a multicomponent fiber; and wherein the second component consists of polyolefin fibers and only the first component is melted.
49. Porous structures, similar to those set forth in claim 40, having a first component, this first component provides the primary separation, green strength and agglutination resistance capabilities; wherein the first component consists of multicomponent fibers; and where this first component melts.
50. Porous structures, similar to those set forth in claim 49, further comprising at least one optional component selected from the group consisting of cationically charged resins, ion exchange materials, pearlite, diatomaceous earth, activated alumina, zeolites. , solutions of resins, latex, materials and metal fibers, cellulose, coal particles, carbon fibers, rayon fibers, nylon fibers, polypropylene fibers, polyester fibers, glass fibers, steel fibers and graphite fibers, including P1131 / 99MX mixtures thereof in an amount ranging between 0.1 and 90 weight percent, with a concomitant decrease in the amount of primary medium.
51. Porous structures, similar to those set forth in claim 50, wherein the optional component is selected from the group consisting of perlite, diatomaceous earth, activated alumina, zeolites, cellulose, rayon fibers, nylon fibers and particles of carbon is cationically charged.
52. Porous structures, similar to those set forth in claim 31, comprising a flat layer.
53. Porous structures, similar to those set forth in claim 52, comprising multiple flat layers, each layer having a specific mixture of components.
54. Porous structures, similar to those set forth in claim 31, comprising structures with hollow shapes.
55. Porous structures, similar to those set forth in claim 54, having an L / D ratio of at least about 3: 1.
56. Porous structures, similar to those set forth in claim 31, comprising shaped structures having a plurality of concentric layers, each layer having a specific mixture of components. P1131 / 99MX
57. Porous structures, similar to those set forth in claim 56, wherein the shaped structures are hollow and have an L / D ratio of at least about 3: 1.
58. Porous structures, similar to those set forth in claim 31, comprising hollow-shaped structures, closed at one end.
59. Porous structures, similar to those set forth in claim 31, comprising smooth outer surfaces.
60. Porous structures, similar to those set forth in claim 31, comprising discontinuous exterior surfaces provided without separate machining post-fabrication.
61. Porous structures, similar to those set forth in claim 31, which are reinforced with fibers and having improved green strength with respect to comparable porous structures devoid of that component which provides green strength reinforcement.
62. Porous structures, similar to those set forth in claim 31, which are reinforced with fibers and which have improved strength in the final product with respect to comparable porous structures devoid of that reinforcement. P1131 / 99MX SUMMARY OF THE INVENTION A porous structure manufacturing process consists of forming a dry blend comprising a component that provides primary separation capacity, a component that provides green strength strengthening capacity and a component that provides agglutination capability and is selected from the group consisting of thermoplastic and thermosetting polymers; distributing the mixture on a suitable surface until having a desired thickness thereof; densify the mixture in the desired form for the porous structure; remove the densified porous structure from the surface; agglutinate the component that provides the primary separation capacity by melting the mixture at a temperature up to about 20eC or higher than the melting point of any thermoplastic component that provides agglutination capacity. Porous structures (100, 110, 120, 125, 140, 175) according to the present invention comprise between about 70 and 90 parts by weight of a component that provides primary separation capacity (61, 62); between about one and 15 parts by weight of a component that provides green strength strengthening capacity (64.65); and between about 8 and 20 parts by weight of a component that provides P1131 / 99MX agglutination (67, 68) and is selected from the group consisting of thermoplastic and thermosetting polymers. P1131 / 99MX