Composite porous materials and methods of making and using the same

[0001] The invention relates to porous composite materials and methods for their preparation and use.

BACKGROUND OF THE INVENTION [0002] Porous membranes have long been used to filter fine solids from liquids. Microfiltration, ultrafiltration, nanofiltration and reverse osmosis / reverse osmosis ("RO") are examples of processes based on the use of porous membranes. Applications that use these processes include purifying salt water to produce drinking water, filtering wastewater for reuse as industrial process water, and removing undesirable solids from certain beverages such as beer and wine.

[0003] Microfiltration processes are generally used in applications where it is necessary to remove relatively large particles from the liquid stream. Microfiltration is generally carried out at lower pressures than ultrafiltration and RO. Applications suitable for microfiltration include, but are not limited to, waste water treatment, oil and water separation, and dedusting.

[0004] Ultrafiltration is a pressure driven membrane process capable of separating solution components based on particle size and shape. Due to the pressure difference applied to both sides of the ultrafiltration membrane, the solvent and small dissolved components pass through the membrane, while larger dissolved components are retained by the membrane. Typical ultrafiltration applications include pretreatment of seawater in desalination plants and treatment of wastewater for reuse as process water.

[0005] Reverse osmosis has found wide application in those filtrations that require filtration of finely divided solids, including dissolved ions. For example, in areas of the world with limited fresh water sources, RO has been successfully used for the treatment of sea water. Typically, each RO membrane in the apparatus is placed inside a tubular, external pressure vessel adapted to withstand the high pressures associated with the RO process. The porous membrane used in the RO process is often attached or coated on the porous drainage layer, creating a sandwich-like structure. Three of the four sides of this "RO membrane sandwich" are sealed. The fourth side of the sandwich is inserted into the gap in the core and spirally wrapped around this core to obtain the desired surface area. The sandwich-type RO membrane is generally made of a material other than the drainage layer material.

[0006] In most cases, the porous membrane used in the above-mentioned filtration processes is attached to the porous substrate. Such porous substrates can be very thin (e.g., 15 mm to 95 mm thick), and are therefore fragile and unable to provide structural support. See, e.g., Examples 1-3 and 9 of US Patent No. 4,828,772 to Lopatin et al. If the porous substrate is able to provide mechanical support for the membrane used in the above-mentioned filtration process (making the membrane better suited to the requirements for the application, e.g. higher pressure), the substrate is made of a material other than the material from which it is made is

Membrane. In general, the membrane and substrate are layered, or the membrane is attached to the substrate. There is no bond between the membrane and the substrate, and hence there is a clear interface between the membrane and the substrate.

[0007] Some membranes used in the ultrafiltration process are composite membranes. Composite membranes, as reported, have been prepared using glycerin as the layer between the ultrafiltration membrane and the microfiltration membrane substrate, each of which can be made of the same polymer. Glycerin works to reduce the effect of the ultrafiltration membrane solution on the microfiltration membrane. See e.g. U.S. Patent Number 4,824,568 to Allegrezza, Jr. et al. and published European Patent Application Number 0596411 A2 to Millipore Corp. These related materials disclose the introduction of glycerin and / or the use of a non-solvent for a microfiltration membrane (which has a thickness of the order of 125 micrometers (mm)) when using an ultrafiltration membrane solution to protect against digestion and / or dissolution of the microfiltration membrane substrate by membrane solution for microfiltration and avoid fusion of the formed ultrafiltration membrane with the microfiltration membrane substrate, even if the membrane and substrate are made of the same polymer.

[0008] Casting a membrane made of one material on a substrate made of another material can result in a material that is poorly suited to many applications, especially when the membrane material and the substrate materials have different solubilities in the casting solvent and different thermal properties. For example, the membrane surfaces of such dissimilar materials are sometimes heterogeneous. The lack of homogeneity reduces the strength with which the membrane adheres to the substrate and can lead to a wide distribution of pore sizes, leading to uneven fluid flow through the membrane and unpredictable performance characteristics.

[0009] Another different circumstance is that different materials used as the membrane and substrate have different chemical and thermal properties. Thus, two different materials (e.g., two different polymers) generally exhibit poor adhesion and a significant amount of hollow cavities at the interface between the membrane and the substrate. This may be due in part to the poor miscibility of two different materials. Bad adhesion can also be caused by different thermal properties of materials, which can lead to stress at their interface, causing delamination and surface cracks. The susceptibility of existing membrane substrates to delamination damage is increased by the pressures used in the filtration process (high pressure is privileged to increase flow during separation). Delamination in existing membrane-substrate systems consisting of two materials is also caused by the frequent application of pressure used for backflushing or flushing of the system. Indeed, reverse leaching is one of the main causes of delamination in membrane substrates consisting of two materials used for microfiltration and ultrafiltration. Thus, it is necessary to provide materials that have strong adhesion between the membrane and the substrate that can be used in various filtration applications.

[0010] In addition, there remains an unmet need for a porous membrane that can be steam sterilized (existing membranes containing polyethylene cannot be steam sterilized) and has greater resistance to back pressure (which provides better cleaning and extended membrane life).

[0011] Existing manufacturing methods for making membrane coated tubular substrates may include completely filling the opening of the vertically oriented pipe with a solution of the membrane material, allowing the weighed device inserted slowly into the interior from top to bottom of the vertical pipe and after performing this operation, extruding the membrane solution through porous surfaces or the walls of the pipe and cleaning the outer surface of the pipe with a ring-shaped device, slightly larger than the outer diameter of the pipe by sliding the ring-shaped device from the top of the pipe downwards. Such methods are not optimal because, for example, they are time consuming, expensive and can lead to uneven membrane coating and uneven depth of penetration of the membrane into the substrate pipe.

[0012] US-A-5,919,370 provides an integral membrane formed from a single high viscosity polymer solution. A single high-viscosity polymer solution is shaped and, during shaping, a viscosity profile is established on the thickness of the membrane by applying a temperature gradient to the membrane. The polymer is then precipitated by diffusion-induced coagulation, leading to different pore sizes between layers A, B and C.

[0013] US-A-5,232,601 provides a filtration medium based on forming a bundle of thousands of membranes in the form of tubular fibers. When used in dialysis procedures, blood flows into the chamber at one end of the housing, and then enters these thousands of membranes in the form of tubular fibers tightly bundled together. Each of the tubular fiber membranes has a dense sponge-like inner surface and an outer surface having large pores and small pores. Tubular fibers are formed from a single polymeric casting solution in a two-stage dry jet wet spinning process. This process produces monolithic or integral tubular fibers with the required pore structure for hemodialysis.

[0014] EP-A-1 063 256 provides an integral microporous membrane produced by cooling the polymer-containing solution, poly (vinylidene fluoride), to form a biphasic gel.

[0015] WO 00/53294 provides systems and methods for producing a three-zone microporous membrane from a single mother mortar.

[0016] WO 99/18282 relates to an industrial fabric suitable for use as a paper machine fabric, conveyor belt or filter cloth. The disclosed material comprises a substrate structure such as a membrane with holes, a sintered layer and a polymer coating.

SUMMARY OF THE INVENTION [0017] The present invention relates, in part, to a composite porous material according to claim

1.

[0018] The present invention also relates to methods for making the porous composite materials described herein.

BRIEF DESCRIPTION OF THE FIGURES [0019] Certain aspects of the present invention may be understood with reference to the accompanying figures in which:

[0020] FIGURE 1 provides a scanning electron microscope ("SEM") photo of a comparative cross section of a PVDF porous membrane cast on a polyethylene porous substrate in which the membrane is not bound to the substrate, at a 60X magnification.

[0021] FIGURE 2 provides a SEM image (same magnification as in FIGURE 1) of a cross section of an exemplary composite porous material prepared according to the principles of the present invention comprising a porous second PVDF material in the pores of an exemplary porous first PVDF material.

[0022] FIGURE 3 provides a SEM image of the cross section of the exemplary porous composite material of FIGURE 2, enlarged 17X.

[0023] FIGURE 4 provides a SEM image of a cross-sectional view of the exemplary composite porous material of FIGURE 2, close to the inner radius, at a magnification of 43X.

[0024] FIGURE 5 provides a SEM image of a cross section of the exemplary porous composite material of FIGURE 2, at 140X magnification, enlarged from FIGURE 4, to show the porous second PVDF material in pores.

[0025] FIGURE 6 provides a SEM image of the cross section of the exemplary porous composite material of FIGURE 2, close to the inner radius, at 250X magnification.

[0026] FIGURE 7 provides a SEM image of a cross section of the exemplary porous composite material of FIGURE 2, enlarged 750X, enlarged to show the porous second PVDF material in pores.

[0027] FIGURE 8 provides a SEM image of a cross section of the exemplary composite porous material of FIGURE 2, enlarged of FIGURE 7, at 2500X magnification, to show the porous second PVDF material in pores.

[0028] FIGURE 9 provides a SEM view of a flat view of the exemplary porous composite material of FIGURE 2, at a magnification of 900X, enlarged to show the porous second PVDF material in the pores.

[0029] FIGURE 10 provides a SEM image of a plan view of the exemplary porous composite material of FIGURE 2, at 5000X magnification, enlarged to show the porous second PVDF material in pores.

[0030] FIGURE 11 shows an exemplary torpedo applicator for applying membrane material within a tubular substrate.

[0031] FIGURE 12 is an end view of the torpedo applicator of Figure 11.

[0032] FIGURE 13 shows the torpedo applicator of FIGURE 11 connected to an exemplary liquid supply system.

DETAILED DESCRIPTION OF THE INVENTION [0033] The present invention includes a variety of porous composite materials. It is understood that the various aspects or features of the invention described herein are separate and independent. Accordingly, a composite porous material or article made in accordance with the principles of the present invention need not have more than one inventive feature described herein, and / or may have a combination of two or more features described herein.

[0034] In one aspect, the present invention relates to a first material (which in one embodiment may be considered as "substrate") having pores having a first average pore size and a second material (which should be considered as being " membrane ") having pores with a second average pore size substantially smaller than the first average pore size. In one embodiment, the second material may cover at least a portion of the surface of the first material. In another embodiment, the second material may be in at least some of the pores of the first material. In another embodiment, the second material may cover at least a portion of the surface of the first material and the second material may be in at least a portion of the pores of the first material. In other embodiments, the second material may cover at least a portion of the surface of the first material and / or at least partially fill some or all of the pores of the first material. In another embodiment, the average pore size of the second material is substantially smaller than the average pore size of the first material. The term "substantially smaller" when used in reference to the average pore size means that the average pore of the second material may be within the average pore of the first material. In aspects of the present invention, the term "substantially smaller", referring to the average pore size, means about 3, 5, 7, 10, 25, 50, 75, 100 greater than about 100, 125, 150, 175, 250, 500, 1,000 or 10,000 times smaller, as determined by methods known in the art and / or disclosed herein. In other aspects of the present invention, the average pore size of the second material is about 3, 5, 7, 10, 25, 50, 75 or 100 times smaller than the average pore size of the first material. In other aspects of the present invention, the average pore size of the second material is greater than about 100 times smaller, or about 125, 150, 175, 250, 500, 1000 or 10,000 times smaller than the average pore size of the first material.

[0035] Although currently the typically porous composite material of the present invention cannot be separated into various components or layers, it can be considered to contain at least two components. As used herein, and unless otherwise indicated, the term "substrate" refers to a layer of porous first material. The specified first material may be sintered. In aspects of the present invention, the thickness of the first material is at least about 100 mm, at least about 250 mm, at least about 400 mm, at least about 600 mm, at least about 800 mm, or at least about 1000 mm. In aspects of the present invention, the thickness of the first material is up to about 10 cm, up to about 5 cm, or up to about 1 cm. In aspects of the present invention, the thickness of the first material is from about 100 mm, to about 10 cm, from about 250 mm to about 5 cm, or from about 1000 mm to about 1 cm.

[0036] As used herein and unless otherwise indicated, the term "membrane" refers to a layer of a second material that forms a membrane structure for microfiltration, ultrafiltration or nanofiltration at the top and / or inside of the first material. In aspects of the present invention, the second material has a thickness less than about 10,000, 1,000, 500, 400, 300, 250, 125, 100, 75, 50, 25 or 10 mm and is permeable to fluid (e.g., water or air). In aspects of the present invention, the thickness of the first material is at least about 1.5, 2, 5, 10, 100, 250, 500, 1000 or 10000 times more than the thickness of the second material. In another embodiment, the thickness of the first material is approximately equal to the thickness of the second material. The second material is bonded by direct physical bond to at least a portion of the surface of the first material and / or bonded by direct physical bond to the walls of at least some pores of the first material.

[0037] As is known in the art, certain membranes, so-called asymmetric membranes, contain a very dense upper layer or "skin" supported by a porous underlying membrane. In one embodiment of the present invention, the second material is an asymmetric membrane. Asymmetric membranes are said to combine the high selectivity of the dense membrane with the high permeability rate of a very thin membrane. (See, e.g., M. Mulder, Basic Principles of Membrane Technology, Kluwer Academic Publishers, Dordrecht (1996), pp. 12-14; U.S. Patent Number 4,824,568, col. 1, lines 42-56 and published European Patent Application Number 0596411, p. 2, lines 32-38). Optionally, the second material of the present invention has such a skin on the second material on a surface distant from the first material. The skin thickness, if present, is up to about 0.1 times the thickness of the second material.

[0038] In aspects of the present invention, more than about 1, 2, 5, 10, 25, 50, 75, 90, 95, 99 or 99.9%, or about 100% of the pores of the first material contain some of the second material. As used herein, and unless otherwise indicated, the term "percent pore" refers to the percentage of the total pore volume of the first material that is occupied after the second material has been applied and can be determined by techniques known in the art (e.g., mercury porosimetry or SEM).

[0039] In aspects of the present invention, the average pore size of the first material is at least 1 mm, at least about 2 mm, at least about 5 mm, at least about 10 mm, or at least about 25 mm. In aspects of the present invention, the smallest pore size of the first material is affected by the desired liquid flow rate through the composite porous material of which it is part. In aspects of the present invention, the average pore size of the first material is up to about 200 mm, up to about 100 mm, or up to about 50 mm. In aspects of the present invention, the largest pore size of the first material is affected by its ability to provide mechanical support to the porous composite material of which it is part. In aspects of the present invention, the average pore size of the first material is from about 1 mm to about 200 m, from about 1 mm to about 100 mm, from about 2 mm to about 200 mm, from about 25 mm to about 200 mm, from about 5 mm to about 100 mm or from about 10 mm to about 50 mm. In aspects of the present invention, when the composite porous materials of the present invention are used for microfiltration applications, the average pore size of the first material is from about 1 mm to about 200 mm or from about 25 mm to about 200 mm. In aspects of the present invention, when the composite porous materials of the present invention are used for ultrafiltration applications, the average pore size of the first material is from about 1 mm to about 200 mm or from about 1 mm to about 100 mm. The average pore size of the first material alone can be determined by mercury porosimetry, e.g. using an AUTOPORE III model 9420 porosimeter from Micrometritics Inc. (Norcross, Ga) or microscopy, e.g. SEM. In aspects of the present invention, the first material has an average porosity of about 20, 30, 40, 50, 60 or 75%.

[0040] In aspects of the present invention, the average pore size of the second material is at least about 0.0002 mm, at least about 0.01 mm, or at least about 0.1 mm. In aspects of the present invention, the average pore size of the second material is up to about 10 mm, up to about 5 mm, up to about 2 mm, or up to about 0.1 mm. In aspects of the present invention, the average pore size of the second material is from about 0.0002 mm to about 10 mm, from about 0.01 mm to about 5 mm, from about 0.01 mm to about 0.1 mm, from about 0.1 mm to about 10 mm, or about 0.1 mm to about 2 mm. In aspects of this

In the present invention, when the composite porous materials of the present invention are used for microfiltration applications, the average pore size of the second material is from about 0.1 mm to about 10 mm. In aspects of the present invention, when the composite porous materials of the present invention are used for ultrafiltration applications, the average pore size of the second material is from about 0.01 mm to about 0.1 mm.

[0041] In aspects of the present invention, the average pore size of the first material is at least about 3, 5, 7, 10, 25, 50, 75, 100 times more than about 100, 125, 150, 175, 250, 500, 1000 or 10,000 times the average pore size of the second material.

[0042] The average pore size and / or porosity of the porous composite material according to the present invention may be determined by known methods such as SEM. Invasive techniques such as mercury porosimetry may also be used. For example, one such technique may be used to determine the porosity of a first material (or porous substrate in one embodiment) before it is used to produce a composite porous material in accordance with the principles of the present invention. This technique can then be used to determine the porosity of the resulting composite porous material. Using these two results, those skilled in the art will be able to easily determine, by difference, the porosity of the second material (or membrane in another embodiment) in the pores of the first material.

[0043] According to another aspect of the present invention, which is connectable but not necessarily present in any of the embodiments described above, the second material is joined by direct physical bonding to the surface and / or pore walls of the first material. In one embodiment, the first material is contacted with a mixture of solvent and polymer and optionally an inorganic salt (to improve the solubility of the polymer, as will be discussed below). One aspect of the present invention relates, in part, to the discovery that by choosing a solvent such that both the second material and the first material are soluble in the solvent, a porous composite material can be produced in which the first material and the second material adhere strongly to each other, and therefore they are very resistant to processes such as delamination. As used herein, and unless otherwise indicated, a polymer such as a second material is "soluble" in solvent if, upon contact, 1 g of polymer and 100 g of solvent at atmospheric pressure and at a temperature of from about 20^aboutC to about 70 ° C, e.g. 25^aboutC, optionally with stirring, after approximately 4 hours no solid polymer residues are visible to the naked eye.

[0044] In one embodiment, e.g. to facilitate strong mutual adhesion, the first material and the second material comprise or are formed of the same polymer or the same copolymer. That is, in connection with the "same polymer", each polymer is made of a monomer with identical chemical structure. In connection with the "same copolymer", each copolymer (e.g., copolymer "1" and "2") is formed from ordinary monomers, i.e. two or more monomers (e.g. "A" and "B"), wherein monomers A in copolymer 1 have the same chemical structure as monomers A in copolymer 2 and monomers B in copolymer 1 have the same chemical structure as monomers B in copolymer 2. For example, for the purposes of this application , linear or branched polyethylene, each formed from ethylene monomer, is considered to be the same polymer. In another example, two copolymers, each prepared from two monomers, such as acrylonitrile and vinyl chloride, but differing in the ratio of acrylonitrile to vinyl chloride contained in each copolymer, are considered to be the same copolymer for the purposes of this application. In 7 more

In another example, two polymers made from one monomer but differing in their average molecular weight are, for the purposes of this application, considered to be the same polymer. In yet another example, two copolymers, each made of the same three monomers, but differing in their average weight molecular weight, are considered to be the same polymer for the purposes of this application. Examples of polymers of this embodiment include fluoro polymers such as poly (vinylidene fluoride) ("PVDF"), polyolefins such as polyethylene and polypropylene, polyacrylonitrile and modacrylic polymers such as Dynel (acrylonitrile with vinyl chloride), polyetherimides, polyether ether ketones ( "PEEK") and poly (vinyl chloride) ("PVC"), but are not limited to these.

[0045] The term "copolymer" as used herein includes a polymer comprising at least two monomer subunits. Hence, a polymer chain containing three different monomers (also known as terpolymer) is included in the term "copolymer" because it is a polymer chain containing more than three different monomer subunits. The term "polymer" as used herein includes a homopolymer and a copolymer.

[0046] In another embodiment, e.g. to facilitate strong mutual adhesion, the first and second materials comprise or are formed of a similar polymer or similar copolymer. That is, in connection with a "similar polymer", each polymer contains a monomer of identical chemical structure. In connection with the "similar copolymer", each copolymer (e.g., "1" and "2" copolymer) is made from a simple monomer, i.e. two or more monomers (e.g. "A", "B" and "C"), wherein the "A" monomers in copolymer 1 have the same chemical structure as the A monomers in copolymer 2, and the B monomers in copolymer 1 differ in their chemical structure compared to C monomers in copolymer 2 For example, for the purposes of this application, a first polymer made from vinylidene fluoride and a second polymer made from vinylidene fluoride and (CH2-ⁱ³CF2) are considered to be similar polymers for the purpose of this application because each of them contains ordinary vinylidene fluoride monomer. In another example, high density polyethylene and ultra low density polyethylene (UL-DPE), each made of ethylene (and for UL-DPE, with a small amount of another olefin monomer), are considered to be similar polymers for the purposes of this application because each has a simple monomer - ethylene. In another example, two copolymers, one random copolymer and another block copolymer, each made of two monomers such as styrene and butadiene are considered similar polymers for the purposes of this application. In yet another example, two polymers, the first made from ethylene and propylene and the other made from ethylene, propylene and 1-hexene are considered to be similar polymers for the purpose of this application, because each of them has two common monomers. [0047] In another embodiment, e.g. in order to facilitate strong mutual adhesion, the first material and the second material contain or are formed from polymers or copolymers containing a related monomer (e.g. "A" and "A"), i.e. each of them belongs to the same "polymer family". For example, for the purposes of this application, poly (methyl methacrylate) and poly (ethyl methacrylate) are thus described because their building monomers are related, differing only in the number of carbon atoms in their ester group as well as poly (methyl methacrylate) and poly (methyl acrylate) differ only in the presence or absence of a methyl substituent. In connection with copolymers from the same polymer family, each copolymer (e.g. copolymer "1" and "2") is made of a related monomer, e.g. from "A", "A", "B" and "C" monomers, where the monomers A in copolymer 1 have a chemical structure related to chemical structure monomers A 'in copolymer 2 and B monomers in copolymer 1 differ in chemical structure compared to C monomers in copolymer 2. Polymer families are known in the art, e.g. polymer textbooks often identify such "polymer families" formed from similar monomers. For example, by F. W.

EP 1 687 133 B1

Billmeyer, Jr., Textbook of Polymer Science (Wiley-Interscience, New York, 2nd edition, 1971) polyolefins, styrene polymers, acrylic polymers, poly (vinyl esters), chlorine-containing polymers were disclosed as separate polymer families (e.g. PVC), fluorine polymers, polyamides, ether and acetal polymers, polyesters, polyurethanes and cellulose polymers. Chemical encyclopedias also often identify such "polymer families". For example, the Kirk-Othmer Encycl encyclopedia. of Chem. Technol. (4th edition, 1991-1998) contains a separate list of many types of polymer families, including fluoropolymers, polyacrylates, polyacrylonitriles, polyamides, polyesters, polyetherimides, polyether ketones, polyether ketone ketones, polyether sulfones, polyolefins, polyethylenes, polypropylenes, polysulfones, vinyl) and vinyl polymers, but not limited to them.

[0048] In another embodiment, e.g. to facilitate strong mutual adhesion, both polymers, the polymer comprising the first material and the polymer comprising the second material are soluble in the solvent, i.e. have a conventional solvent. The term "ordinary solvent" as used herein means, for example, that if the "P" polymer is soluble in the "X" solvent and the "Q" polymer is soluble in the "X" solvent, the "X" solvent is the usual solvent for the "P" polymer "And polymer" Q ". The term "ordinary solvent" as used herein includes a mixture comprising a plurality of solvents. For example, in one embodiment, the ordinary solvent is a mixture of two solvents, e.g. a mixture of dimethylacetamide and dimethylformamide in any suitable proportion.

[0049] In another embodiment, the first material and / or second material are made of a fluorine polymer, i.e. a fluorine-containing polymer or copolymer, such as polyvinyl fluoride, such as the TEDLAR product line from DuPont (Wilmington, Germany) and PVDF, such as the KYNAR and KYNAR FLEX product lines, e.g., KYNAR FLEX 2800, KYNAR 500 and KYNAR 460 from Atofina Chemicals, Inc., (Philadelphia, PA), but are not limited to them. In another embodiment, the first material and / or second material is made of PVDF. In another embodiment, the first material and / or second material is made of polyolefins, such as polyethylene, such as the HOSTALEN GUR product line, e.g., HOSTALEN GUR 400 from Ticona Engineering Polymers (Florence, KY), and polypropylene, such as the PRO- FAX from Basell NV (Hoofddorp, The Netherlands), but not limited to them. In another embodiment, the first material and / or second material is made of polyethylene. In another embodiment, the first material and / or second material is made of polypropylene. In another embodiment, the first and / or second material is made of acrylic polymers such as polyacrylonitrile such as the BAREX product line from BP Petrochemicals (Naperville, IL) and modacrylic polymers such as acrylonitrile and vinyl chloride copolymer such as the former DYNEL product line available from Union Carbide (Danbury, CT), but not limited to them. In another embodiment, the first and / or second material is made of polyacrylonitrile. In another embodiment, the first and / or second material is made of a copolymer of acrylonitrile with vinyl chloride. In another embodiment, the first and / or second material is made of polyetherimide, such as the ULTEM product line, e.g. Ultem 1000 from GE Advanced Materials (Pittsfield, MA), but not limited to them. In another embodiment, the first material and / or second material is made of a polyether ether ketone, such as the KADEL product line from Solvay Advanced Polymers (Alpharetta, GA) and the PEEK product line from Victrex PLC (UK), but not limited to them. In another embodiment, the first material and / or second material are made of chlorine-containing polymers, such as PVC, e.g., the GEON product line from Geon Co. (Avon Lake, OH), but not limited to them. In another embodiment, the first and / or second material is made of PVC.

[0050] In another embodiment, the first material and / or second material is made of polysulfone, such as the ASTREL polysulfone product line from 3M (Minneapolis, Mn) and the UDEL polysulfone product line, e.g. UDEL P-3500 and UDEL P-3500 LCD and MINDEL mixed polysulfone products line, from Solvay Advanced Polymers, but not limited to them. In another embodiment, the first material and / or second material is made of polyethersulfone, such as, but not limited to, the RADEL A polyethersulfone product line from Solvay Advanced Polymers. In another embodiment, the first material and / or second material is made of polyester such as the EKTAR polyester product line from Eastman Chemical Co. (Kingsport, TN) and poly (ethylene terephthalate), e.g. lines of IMPET polyester products from Ticona, but not limited to them. In another embodiment, the first material and / or second material are made of polyamide, such as the CELANSE PA 6.6 product line, from Ticona and the CAPRON PA6 polyamide product line and ULTRAMID PA6, PA 6.6 and PA 6/6, 6 from BASF (Wyandotte, MI), but not limited to them.

[0051] Another embodiment of the present invention, notwithstanding the embodiments described above and yet which can be combined with them, includes a material comprising a porous second material combined with a sintered porous second material, thus providing a porous composite material where two materials are made of the same polymer. Another embodiment of the present invention, notwithstanding the embodiments described above and yet capable of being combined with them, includes a material comprising a porous second material combined with a sintered porous second material, thus providing a porous composite material, where two materials are made of similar polymers. Another embodiment of the present invention, regardless of the embodiments described above and yet connectable to them, includes a material comprising a porous second material combined with a sintered porous second material, thus providing a porous composite material, where two materials are made of polymers from the same family. Another embodiment of the present invention, notwithstanding the embodiments described above and yet connectable to them, includes a material comprising a porous second material combined with a sintered porous second material, thus providing a porous composite material, where the two materials are made of polymers that contain ordinary solvent.

[0052] In another particular aspect, the second material is connected directly to the sintered first material, i.e. no other solid or liquid substance is allowed between the first material and the second material. In another particular aspect, the second material is bonded directly to the surface of the sintered first material. In another particular aspect, the second material is connected directly to certain pore walls of the sintered first material. In another particular aspect, the second material is connected directly to the surface and to certain pore walls of the sintered first material.

[0053] As used herein, and unless otherwise indicated, the term "combined" refers to the direct physical connection between two components, e.g., first material and second material or substrate and membrane, which may be both of identical material or of different materials. In the combined composite porous material of the present invention, the first material and the second material are in contact with each other and at least a portion of this contacting material is directly bonded and is difficult to separate into components. Accordingly, a second material, such as the one that forms the membrane, is resistant to delamination from the first material, such as the one that forms

And a more resistant porous composite material is obtained, e.g. compared to prior art filters or filter materials.

[0054] In another embodiment, the present invention includes a pipe comprising a sintered porous tubular first material made of a first material having pores having a first pore size with a second material in at least some of the pores of the first material. The second material has pores of a second average size substantially smaller than the first average size and forms a second material on the inner surface of the tubular first material, is connected directly to certain pore walls of the tubular first material and the first material and the second material consist of the same polymer, similar polymers or from the same polymer family or are soluble in the same solvent.

FIRST MATERIAL [0055] The first material is typically made in a given desired configuration and, in one embodiment, can be considered as a substrate for holding a second material that can be considered to be a membrane. In another embodiment, the first material is in the form of a flat sheet; in another embodiment, the first material is in the form of a hollow tube; in another embodiment, the first material is in the form of a molded piece of any shape.

[0056] Many methods known to those skilled in the art can be used to make porous first materials. Some examples include sintering, such as disclosed in US Patent No. 6,030,558, which is incorporated herein in its entirety as bonded material; using blowing agents and / or leaching agents; methods for producing microcellular material, such as disclosed in US Patent Nos. 4,473,665 and No. 5,160,674, each of which is incorporated in its entirety as a bound material; drilling, including laser drilling and reverse phase precipitation. Depending on the method of manufacture, the porous first material may thus have regular arrangement of channels with random or well-defined diameters and / or randomly arranged pores of various shapes and sizes. Pore ​​sizes are typically reported in terms of their average diameters, even if the pores themselves are not necessarily spherical.

[0057] Preferred first materials of the present invention are produced by sintering the particles of at least one polymer (e.g. plastic) and optionally particles of other additives. These optional additives may include, but are not limited to, those known in the art, such as lubricants, colorants, functional additives, antimicrobials, antistatic agents and fillers. In one embodiment, the additive is provided in the form of particles.

[0058] In one embodiment, the polymer particles and the optional additive particles are mixed to form a relatively homogeneous solid dispersion, which is then sintered. Depending on the desired size and shape of the final product (e.g. block, tube, cone, cylinder, sheet or foil), this can be done using a mold or other technique known to those skilled in the art. In another embodiment, the solid dispersion is sintered in a mold. Suitable forms are available on the market and are known to those skilled in the art. Specific examples of molds include flat sheets greater than about 0.01 inch (254 mm) thick, flat sheets up to about 1 inch (2.54 cm) thick, flat sheets from about 0.01 inch (254 mm) to about 1 inch (2.54 cm) and round cylinders of different heights and diameters, but are not up to

EP 1 687 133 B1 limited. Suitable mold materials include, but are not limited to, metals and metal alloys such as aluminum and stainless steel and thermoplastics that are high temperature resistant. [0059] In one embodiment, compression compression is used to provide the sintered first material. In this embodiment, the mold is heated to the sintering temperature of the first material, allowed to level, and then subjected to pressing. This pressure is typically greater than about 1 psi (6,890 Pa) and typically less than about 100 psi (689.00 Pa), depending on the composition of the sintered material and the desired porosity of the final product. Generally, the higher the pressure applied to the mold, the smaller the average pore size and the greater the mechanical strength of the final product. The time during which pressure is applied also varies depending on the desired porosity of the final product.

[0060] Once the porous first material has been generated, the mold is allowed to cool. If pressure has been applied to the mold, cooling may occur at still maintained pressure, or after pressure has been removed. The sintered first material is then removed from the mold and eventually processed. Examples of optional treatments include, but are not limited to, sterilization, cutting, grinding, polishing, embedding and / or coating.

[0061] Using methods such as those described above, a variety of materials, of various sizes and shapes, can be used to provide the appropriate porous first material. In one embodiment, the sintered particles have approximately the same dimensions, i.e. they have a size range such that 50% of the particles, by number, are in the range of ± 50% of the average particle size. In this embodiment, the particle size is relatively uniform (e.g. as determined by means of commercially available sieves), i.e. the particle size distribution is relatively narrow. This is considered advantageous because the particles of approximately the same dimensions can be compactly packed into the mold and because the narrow particle size distribution allows the production of a homogeneously porous material (i.e. the first material comprising pores that are evenly distributed in the material and / or are approximately equal dimensions). This is also beneficial, e.g. in the case of filtering liquids, since liquids tend to flow more evenly through an evenly porous material than through a material with approximately equivalent porosity, but having areas with higher porosity and less porosity. Homogeneously porous first materials also probably have fewer weak spots than materials that contain non-uniformly distributed pores of substantially different sizes. From the point of view of these advantages, if the material is commercially available in the form of particles, it is preferably sorted or screened before use to provide the desired average dimensions and narrow particle size distribution. However, many polymers are not commercially available in the form of particles. Consequently, methods such as milling at low temperatures or tabletting under water can be used to prepare the particles of a given polymer.

[0062] Low temperature milling is a known method that can be used to produce particles and / or additive particles of different sizes. However, because low temperature milling typically provides little control over the dimensions of the particles produced, the particles produced by this method may require further processing, e.g., sorting, to ensure that the particles to be sintered will have the desired average size and narrow size distribution.

[0063] Particles for forming the first material of the present invention can also be produced by so-called "underwater tabletting". Tabletting under water is described for example,

EP 1 687 133 B1 in column 3 of US Patent No. 6,030,558 to Smith et al, which is hereby incorporated in its entirety as a bound material. This method offers a number of benefits. Underwater tabletting provides accurate control of the average size of particles produced, in many cases eliminating the need for an additional sorting step and reducing the amount of waste material. Another benefit of tabletting under water is the fact that when spherical particles are needed, the almost exactly spherical shape of the particles obtained allows obtaining sintered material with greater strength. Another benefit of tabletting under water is the fact that due to the almost spherical shape of the resulting particles, a perfect, more homogeneous sintered first coating material with a solution of a second material in which this solution flows into a homogeneous, smooth, porous first material can lead to a more homogeneous porous composite material. Another benefit is that underwater tableting can increase the extent of chemical and / or temperature compatibility of porous pipes made from underwater tableting particles. A further advantage of tableting under water is that when tabletting under water it is possible to incorporate active materials, e.g. antiviral or antibacterial agents, such as the substances described in columns 6-9 of US Patent No. 6,551,608 B2 to Yao (which is hereby incorporated herein in its entirety as a bound material) and / or ordinary polymer additives, e.g. fillers such as carbon black and other additives known in the art, such as those compiled in Concise Polymeric Materials Encyclopedia, JC Salamone, ed. (CRC Press LLC, Boca Raton, Fl, 1999) pp. 23-29 (which is hereby incorporated in its entirety as bonded material) into the particles in order to impart the operational or physical characteristics of the first material.

[0064] Particle forming using underwater tableting typically requires an extruder or melt pump, underwater tablet press and dryer. The first plastic material is fed to an extruder or melt pump and heated to melt. The combined material is then forced through the nozzle. When the material leaves the nozzle, at least one rotary knife cuts it into pieces called "pre-particles". The extrusion speed and speed of the rotary knife (s) determine the shape of the pre-particles, while the diameter of the hole determines their average size. A coolant or coolant capable of increasing the rate at which pre-particles are cooled, e.g. water (hence "under water" in "tableting under water"), flows over the cutting knife (s) and through the cutting chamber. The liquid solidifies the initial particles into particles, which are then separated from the coolant (e.g. water), dried and collected.

[0065] The average size of the particles produced by tabletting under water can be accurately adjusted, from a diameter of at least about 0.01 inches (254 mm). The average size of the particles tabletted under water can be precisely adjusted to a diameter of about 0.25 inches (0.64 cm). The average particle size of tablets compressed under water can be from about 0.01 inch (254 mm) to about 0.25 inch (0.64 cm). The average particle size can be simply adjusted by changing the nozzle with a larger opening to produce proportionally larger particles. The average particle shape can be optimized by changing the extrusion rate, the temperature of the coolant used in the method and / or the speed of the cutting tool of the tablet press.

[0066] While the properties of the porous material may depend on the average size and size distribution of the particles used to make it, the average particle shape may also affect the material's properties. In accordance with one aspect of the present invention, the particles of the first material may be substantially spherical. Essentially spherical particles, and especially those with smooth corners, also tend to sinter more evenly over a well-defined temperature range, providing product 13

EP 1 687 133 B1 final with desired mechanical properties and porosity. This shape facilitates the effective packing of particles in a mold. As used herein to describe particles, the term "substantially spherical" means that the particle is spherical or that the length of its longest radius is not more than about 2 times, preferably not more than 1.5 times, more preferably not more than 1.2 times the length of its shortest radius. When used to describe a mixture or collection of particles, the term "substantially spherical" means that more than about 50% by weight, preferably more than 75% by weight and most preferably more than 95% by weight the particles are essentially spherical. In one embodiment, the first material consists of particles that are sintered together. In another embodiment, the first material consists of substantially spherical particles that are sintered together.

[0067] According to one aspect of the present invention, if the particles of the first material used are commercially available or are made by milling at low temperatures, they may optionally be heat-treated to provide smooth edges and / or sorted to ensure proper average dimensions and distribution dimensions. Heat treatment is a known process in which the particles are quickly mixed and possibly heated so that their sharp corners become smooth. See e.g. U.S. Patent No. 6,551,608 B2 to Yao. Mixers suitable for heat treatment include high intensity mixers, W series, available from Littleford Day, Inc., Florence, KY. Particles produced by tabletting under water that allows precise control of the particle size and can produce smooth, essentially spherical particles, need not be heat treated or sorted, although such treatment after tabletting can optionally be used.

[0068] The specific method used to form the pores or channels in the porous first material and the resulting porous structure (e.g., average pore size and / or porosity) of the porous first material may vary depending on the desired application for which the final composite porous material will be used. As is known in the art, "porosity" is the ratio of the volume of empty space to the volume calculated based on the dimensions of the sample circumference. The desired porosity of the first material can also be influenced by the characteristics or properties of the first material itself. For example, porosity can be influenced in different ways by the shape of the first material and / or its physical properties (e.g., tensile strength and durability). Thus, by forming the first material from different materials having different properties, the strength and / or performance (e.g., flow of liquid flowing) of the resulting porous composite material can be influenced.

[0069] In one embodiment, the first material has sufficient structural stability that allows the shape of the composite porous material to be retained. In another embodiment, the first material has sufficient structural stability to withstand exposure to, e.g., a solvent from a solution of the second material. In another embodiment, the first material has sufficient structural stability to ensure the structural integrity of the composite porous material during its use, e.g., under high pressure, or under the influence of liquid flow, without the need for any further supporting layer.

[0070] In another embodiment, the first material of the porous composite material has a "thicker" pore structure, i.e., the first average pore size is greater than about 5 mm and is at least 10 times larger than the second average pore size of the second material, and it is believed that due to this the coarse first material gives structural durability to the composite porous material of which it is a component.

EP 1 687 133 B1

PROPERTIES OF A POROSIVE COMPOSITE MATERIAL ACCORDING TO THE INVENTION [0071] The composite porous materials of the present invention provide many advantages, e.g. they are resistant to high pressure damaging effects, are resistant to delamination, can be steam sterilized and have higher resistance to back pressure, which enables better cleaning and longer membrane life.

[0072] The present invention includes a number of embodiments and features or inventive aspects as described above that may appear alone or in combination in a composite porous material prepared according to the principles of the present invention. For example, in one embodiment, the present invention includes a pipe of porous composite material, comprising a sintered porous tubular first material made of a first material, having pores of a first medium size, with a second material in at least some pores of the first material. The second material has pores of a second average size, generally smaller than the first average size. The second material is connected directly to some of the pore walls of the tubular first material and the first material and the second material consist of or are made of the same polymer, or a similar polymer, or from the same polymer family. [0073] In another embodiment, the present invention includes a pipe of a porous composite material, comprising a sintered porous tubular first material, formed from the first material, having pores of a first average size and a second material in at least some pores of the first material. The second material has pores of a second average size, generally smaller than the first average size. The second material is directly connected to some of the pore walls of the tubular first material, and the polymer component of the first material and the second material consist of, or are made of, the same polymer or similar polymer, or from the same polymer family.

[0074] In another embodiment, the present invention includes a composite porous material, wherein the first material has a polymer component that consists essentially of a single polymer. In another embodiment, the present invention includes a composite porous material, wherein the second material has a polymer component that consists essentially of a single polymer. In another embodiment, the present invention includes a porous composite material, wherein the first material has a polymer component that consists essentially of a single polymer and the second material has a polymer component that consists essentially of a single polymer.

[0075] In another embodiment, the present invention includes a porous composite material, wherein the first material has a polymer component that consists essentially of at least two polymers, for example, two polymers. In another embodiment, the present invention includes a composite porous material, wherein the second material has a polymer component that consists essentially of at least two polymers. [0076] In another embodiment, the present invention includes a composite porous material, wherein the first material has a polymer component that consists essentially of a single polymer, and the second material has a polymer component that consists essentially of at least two polymers. In another embodiment, the present invention includes a porous composite material, wherein the first material has a polymer component that consists essentially of at least two polymers and the second material has a polymer component that consists essentially of a single polymer. In another embodiment, the present invention includes a composite porous material, wherein the first material has a polymer component that folds

Essentially at least two polymers and the second material has a polymer component that consists essentially of at least two polymers.

[0077] In another embodiment, the porous second material is present on one (or more) surface of the porous first material. In a specific embodiment, the porous second material is a membrane on one (or more) surface of the porous first material. In another particular embodiment, the second material that forms the membrane on one (or more) surface of the porous first material is also in the pores of the first material, and in particular on at least some pore walls within the first material. It is believed that such membranes may limit the rate of diffusion through them, however, they increase the separation capacity of such porous composite materials.

[0078] In a specific embodiment, one or each of the first material and the second material consists of additional polymers. For example, the second material may consist of PVDF, while the first material may consist of a mixture of PVDF and another polymer; the first material may consist of PVDF, while the second material may consist of a mixture of PVDF and another polymer, e.g. polyvinylpyrrolidone ("PVP"); or the first material may consist of a mixture of PVDF and another polymer, while the second material may consist of a mixture of PVDF and another polymer, where the other polymer mixed with the first material may be identical or different from the other polymer mixed with the second material.

[0079] The structure of certain materials, manufactured in accordance with the principles of the present invention, can be understood with reference to the attached figures. For example, for comparison, FIGURE 1 provides SEM images, at 60 times magnification ("60X" or "X60"), a comparative structure made by casting PVDF on a polyethylene substrate, but not containing PVDF combined with the polyethylene substrate according to the rules of the present invention. From this photo it is clear that the PVDF porous membrane is not connected to the polyethylene substrate.

[0080] FIGURE 2 provides a SEM image, at a magnification of 60X, of an exemplary composite porous material, prepared in accordance with the principles of the present invention, made by applying a second PVDF material to form a second PVDF material on the first PVDF material as described below in Example 3. When compared to FIGURE 1, at the same magnification as in FIGURE 2, from FIGURE 2 it is clear that the porous second material is connected to the pore walls of the first material. FIGURE 2 also shows that the second material is present on the surface (e.g., the outer surface) of the first material. The second material has an average pore size of about 0.1 mm, which is substantially smaller than the average pore size of the surrounding area of ​​the first material (about 80 mm). It can further be seen from FIGURE 2 that the second material is in the pores of the first material in areas adjacent the pore walls.

[0081] FIGURES 3, 4 and 5 each provide a SEM image of the exemplary composite porous material produced in Example 3. FIGURE 3 shows an enlargement of 17X. FIGURE 4 shows a 43X magnification. FIGURE 5 shows an 140X magnification. As is clear from each of these photos, the porous second material is combined with the pore walls of the first material. These figures also show, for example, that the second material is in the pores of the first material.

[0082] FIGURE 6 provides a SEM photo, at 250X magnification, of an exemplary composite porous material produced in Example 3. This figure shows, for example, that the second material covers at least a portion of the surface of the first material, wherein at least a portion of the second material is

EP 1 687 133 B1 combined with the first material and that the second material is in certain pores of the first material, wherein at least a portion of the second material is connected to certain pore walls of the first material.

[0083] FIGURES 7 and 8 each provide a SEM image of the exemplary composite porous material produced in Example 3. FIGURE 7 shows a 750X magnification. FIGURE 8 shows a magnification of 2500X. These figures show, for example, that at least part of the second material is combined with the first material.

[0084] FIGURES 9 and 10 each provide a SEM image of the exemplary composite porous material produced in Example 3. FIGURE 9 shows a magnification of 900X. FIGURE 10 shows a magnification of 5000X. These plane view figures show, for example, the pores of the second material. FIGURE 9 also shows, for example, the pore structure of the second material in the pores of the first material. FIGURE 10 also shows, for example, the pore structure of the second material on the surface of the first material.

METHODS OF MAKING A COMPOSITE POROSITE MATERIAL ACCORDING TO THE INVENTION [0085] Various methods can be used to produce a second material in the pores of the porous first material described above and / or in contact with its surface.

[0086] In accordance with another aspect of the present invention, the invention includes a method of making a porous composite material, which comprises applying a solution in a solvent and a second polymeric material dissolved in the solvent to the sintered porous first material. The first material is either the same polymer, a similar polymer or polymer of the same polymer family as the second material, or the first polymer is soluble in the solvent.

[0087] In accordance with another aspect of the present invention, the invention includes a method of making a composite porous material, which comprises applying a solvent solution, a second polymeric material dissolved in a solvent, and an inorganic salt on the sintered porous first material. The first material is either the same polymer, a similar polymer, or a polymer of the same polymer family as the second material, or the first polymer is soluble in the solvent.

[0088] In one embodiment, the second material is made by applying a solution of at least one polymer, a solvent and optionally, but preferably, an inorganic salt, to the porous first material and precipitating the polymer from the applied solution under conditions sufficient to apply the porous second material to the surface and / or in the pores of the first material.

[0089] The solvent is selected such that the second polymeric material (s) is soluble in it.

Solvents that can be used in solution are known in the art and may be different depending on the particular polymer used and the desired properties of the resulting porous second material. Examples of solvents include dimethylacetamide ("DMAc"), dimethyl sulfoxide ("DMSO"), dimethylformamide ("DMF"), N-methylpyrrolidone ("NMP"), triethyl phosphate ("TEP"), isopropyl alcohol ("IPA"), glycol triethylene ("TEP"), mineral oil and any mixture thereof, but are not limited to these.

[0090] Inorganic salts are known in the art and may vary depending on the particular polymer used and the desired properties of the resulting porous second material. Examples of inorganic salts include lithium chloride, zinc chloride, sodium chloride, potassium chloride, lithium bromide, zinc bromide, sodium bromide, potassium bromide and any mixture thereof, but are not limited thereto. In one embodiment, 17

The inorganic salt is lithium chloride, zinc chloride, or any mixture thereof. In another embodiment, the inorganic salt is lithium chloride.

[0091] Application of the second material solution can be facilitated by the use of a suitable spraying / leveling device when contacting the solution with the first material, e.g. a squeegee / trowel, such as a glass rod described in Example 2 below. Application of the second material solution can also be facilitated by the use of a suitable solution ejection device, e.g. a trowel, such as a steel ball and glass rod, as described in Examples 3 and 10 below, respectively, after contacting the solution with the first material.

[0092] In accordance with one aspect of the present invention, the solution ejecting device may be uniquely shaped to apply an even coating of the material solution to the interior of the tubular element. For example, the solution ejection device may be elongated, e.g. rod-like or cylindrical. In particular, the shape of the solution ejection device may be chosen to include contact surfaces compatible with the tubular element. For example, a solution ejection device for applying a material solution to the inner surface of a tubular element may include cylindrical contact surfaces matched to the cylindrical interior of the tubular element. The dimensions of the solution ejection device can be selected to control the amount and / or thickness and / or evenness of the solution of the material to be applied. Application of the material solution can also be facilitated by the use of a suitable device during and after contacting the material solution with the element on which the solution should be applied.

[0093] In accordance with another aspect of the present invention, in which the polymer solution is applied to the inner surface of the pipe, in combination, but not necessarily present in any of the embodiments described above, instead of spraying / leveling or extruding the solution, the solution can be applied using an empty applicator second material, e.g. the torpedo applicator described in Example 4 below, which dispenses the solution during its movement through the opening of the porous tube, in one embodiment of the porous tube of the first material and in another embodiment of the tubular substrate. For example, the applicator may have an internal socket and one or more channels from the internal socket outside the applicator. A polymer solution, such as a solution of a second material, in one embodiment, and a membrane solution in another embodiment, can be fed into the internal socket in the applicator, for example, through a supply pipe from which it can pass from the internal socket through channels outside the empty applicator. Thus, after the relative axial movement of the tubular element and the applicator placed in the tubular element and after the solution has been delivered to the applicator, the solution is dispensed and applied along the inner surface of the tubular element. Measured dosing, as such, e.g. a solution of a second material, provides controlled application conditions for the solution and facilitates uniformity and / or smoothness of the material on the tubular element. In addition, the use of an applicator makes it possible to use a smaller amount of solution, which ensures greater economics of the method. The rate and / or pressure at which the solution is fed to the applicator can be selected to achieve the desired thickness and / or uniformity and / or smoothness of the solution applied to the inner surface of the tubular element.

[0094] In one embodiment, a drive rod is provided to provide motion to the applicator. For reasons of convenience, in another embodiment, the drive rod also acts as a tube providing a solution to the interior of the applicator for applying to the inner surface of the tubular element.

[0095] If desired, a reservoir and channel (s) can be formed along the outer surface of the applicator extending from the empty interior of the applicator outside the applicator transporting the solution to the reservoir. For example, tank 18 in the torpedo applicator in FIGURE 11 is such a tank. The tank is constructed to maintain a supply of solution, e.g. between the walls of the tank 13a outside the applicator and thereby allow a uniform application of the solution to the inner surface of the tubular element.

[0096] In one embodiment, the applicator can be constructed and shaped to facilitate the application of a material solution to the inner surface of the tubular element and control of the amount and / or thickness and / or uniformity of material applied by the apparatus. For example, the applicator may have an elongated shape, e.g. rod-like or cylindrical. In particular, the orientation of the elongated applicator is easier to control than the non-elongated applicator, e.g., spherical or cube-shaped. Hence, the elongated applicator is advantageous when a reservoir is provided along the outer surfaces of the applicator, since the easy orientation of the elongated applicator easily aligns the reservoir relative to the inner surface of the tubular element.

[0097] In one embodiment, the applicator may have a bevelled, e.g., conically-shaped, initial leading edge for insertion to allow easy insertion into the tubular element and simple positioning of the applicator in the tubular element. In another embodiment, the applicator has a bevelled leading edge for application (i.e., the leading edge during application of the solution) to allow easy insertion into the tubular element to start applying the solution. In another embodiment, the applicator has a bevelled leading edge for insertion and a bevelled leading edge for application.

[0098] The dimensions of the applicator can be selected to achieve the desired thickness and / or evenness and / or smoothness of the solution applied to the inner surface of the tubular element. For example, the dimensional difference between the applicator, e.g., the outer diameter of the circular surface on the contact surface 12 and 14 of the torpedo applicator in FIGURE 11, and the dimensions of the inner surface of the tubular element, e.g. the inner diameter of the tubular substrate 26 in FIGURE 11 is set to maintain the solution in the applicator tank and to allow the liquid to build pressure relative to the inner surface of the tubular element while controlling the amount and / or thickness and / or uniformity of the solution applied to the inner surface of the tubular element . The choice of the difference in the dimensions of the outer diameter of the applicator and the inner diameter of the pipe element is influenced by factors such as solution viscosity, surface tension of the solution and surface energy of the inner surface of the pipe element. In one case, if the difference in dimensions between the outer diameter of the applicator and the inner diameter of the tubular element is too small, this may prevent the applicator from moving easily inside the tubular element. Otherwise, if the dimensional difference between the outer diameter of the applicator and the inner diameter of the tubular element is too large, the solution may not be restricted by the walls of the tank and / or the solution may be applied in an uncontrolled manner.

[0099] The cross-sectional shape of the applicator may be selected to match the internal cross-sectional shape of the tubular element. For example, the applicator and the tubular element, each of them may have a round, elliptical, rectangular or square cross-section. Another benefit of adjusting the applicator cross section according to the inner cross section of the tubular element is that the applicator can be initially passed through the opening of the tubular element one or more times before

By introducing a solution. By doing so, irregularities in the inner surface of the tubular element can be reduced or eliminated, e.g. deburring can take place, possibly with removal of loose impurities, e.g. by vacuum suction.

[0100] In one embodiment, for a round tubular element, more even application of the solution can be facilitated by relative rotation of the applicator and the tubular element, especially when applying the solution to the inner surface of the tubular element. The rotation can be transmitted in any manner known in the art, such as manually, or by means of rotational speed controlled apparatus, e.g. for a tubular element, a driven rotating carriage with a rim (with a flat surface of the rim without grooving) on ​​the axis, a horizontal roller mixer or driven roller conveyor of sufficient length to support the tubular element in a horizontal position. In one embodiment, a series of rollers can be used to provide simultaneous machining of a series of tubular elements. In aspects of the present invention, the relative rotational speed is at least about 10 revolutions per minute (rpm) or at least about 36 rpm. In aspects of the present invention, the relative rotation speed is up to about 100 rpm or up to about 44 rpm. In aspects of the present invention, the relative rotational speed is from about 10 rpm to about 100 rpm or from about 36 rpm to about 44 rpm.

[0101] The relative axial movement of the applicator and the tubular element, once or repeatedly, can be implemented in any manner known in the art, such as manually, e.g. using a linear drive table with a hand crank and a control stopwatch, or by means of pulling apparatus with controlled speed, e.g. adjustable speed drawing machines such as those available from Gatto Corp. (Bay City, MI), longitudinal carriage lathe or programmable linear actuator controlled by a logic regulator. In aspects of the present invention, the relative speed of the applicator and the tubular element is at least about 20 cm / min or at least about 25 cm / min. In aspects of the present invention, the relative speed of the applicator and tubular element is up to about 305 cm / min or up to about 165 cm / min. In aspects of the present invention, the relative speed of the applicator and tubular element is from about 20 cm / min to about 305 cm / min or at least about 25 cm / min to about 165 cm / min.

[0102] The pressure of the solution delivered to the applicator can be adjusted in any way known in the art, e.g. by means of a pressure head driven by gravity or a pump with a constant output pressure. In aspects of the present invention, the pressure is at least about 3 psi (20700 Pa) or at least about 4 psi (27600 Pa). In aspects of the present invention, the pressure is up to about 10 psi (69,000 Pa) or up to about 8 psi (55,200 Pa). In aspects of the present invention, the pressure is from about 3 psi to about 10 psi or from about 4 psi to about 8 psi.

[0103] The volume flow rate of the solution delivered to the applicator can be adjusted in any way known in the art. In aspects of the present invention, the volumetric flow rate is at least about 10 ml / min or at least about 40 ml / min. In aspects of the present invention, the volumetric flow rate is up to about 200 ml / min or up to about 140 ml / min. In aspects of the present invention, the volumetric flow rate is from about 10 ml / min to about 200 ml / min, or from about 40 ml / min to about 140 ml / min.

[0104] The applicator of the present invention, which applies a solution to the inner surface of a tubular element, can be used when the longitudinal axis of the tubular element is horizontally (see, e.g., Example 4) or vertically (see, e.g., Example 8).

[0105] In one aspect of the present invention, because the solvent dissolves the second material (e.g., membrane in one embodiment) and the first material (e.g., substrate in one embodiment), it is believed that the solvent may act by dissolving or at least by softening the surface of the porous first material during application from the solution such that at least a portion of the porous second material attaches to the surface of the porous first material. In another embodiment, the first material and the second material that come into contact with each other contain or include the same polymer, and accordingly, the solvent can dissolve or soften this polymer in any material, thereby promoting the combination of the first and second materials at the same time. their contact. In another embodiment, the first material and the second material that come into contact with each other contain or include similar polymers, and accordingly, the solvent can dissolve or soften these polymers in any material, thereby promoting the combination of the first and second materials at their contact. In another embodiment, the first material and the second material that come into contact with each other contain or include a polymer component from the same polymer family, and accordingly, the solvent may dissolve or soften this polymer component in each material, thereby promoting the combination of the first and second material on their contact.

[0106] When the solution is applied to the first material, e.g. in any of the methods described above, the resulting product from this process may be contacted, e.g. immersed in a miscible liquid that is miscible with the solvent from the solution of the second material but is a non-solvent for a polymer of a second material dissolved in the solution. It is known in the art that such contact leads to a porous second material. A porous second material of a porous composite material is formed after precipitation of the polymer (s) from the polymer solution. The properties of the second material can be changed by controlling parameters such as the amount (s) and type (s) of the polymer (s) in solution, type of solvent, addition (s) of inorganic salts (s), coating thickness, composition of the dip bath and temperature dipping baths. The effects provided by these variables are known in the art and can be easily determined.

[0107] In many cases, the preferred miscible liquid is water, although other liquids may be used. For example, water-alcohol solutions can be used. Contact with a miscible liquid can be accomplished by any suitable method known in the art, e.g. by immersion in a bath with a miscible liquid. In one embodiment, the composite porous material is immersed in one bath of miscible liquid. In another embodiment, the composite porous material is immersed in successive baths of miscible liquid (s). In another embodiment, each subsequent bath contains the same miscible liquid. In another embodiment, each subsequent bath contains a different miscible liquid.

[0108] Optionally, after contact with any / all miscible liquids, the composite porous material may be washed away. Optionally, after contact with any / all miscible liquids, the composite porous material may be dried. Optionally, after contact with any / all miscible liquids, the composite porous material may be washed and then dried. Elution can be done with any suitable liquid known in the art, e.g. water. Elution can be carried out by any method known in the art, e.g. by immersing the composite porous material in a wash liquid bath. Drying can be accomplished by any method known in the art, e.g., drying porous composite material in air at about 25^aboutC, or using a conventional belt or stationary dryer at a temperature of about 25^aboutC, or at elevated temperature.

[0109] In a specific embodiment, a composite porous material is produced by applying a solution of a second polymer-containing material (e.g., PVFD) at a concentration of at least about 5 wt. and an inorganic salt (e.g., LiCl) in a solvent (e.g., DMAc or a 50/50 mixture by volume of DMAc and NMP) on the porous first material. In another specific embodiment, the composite porous material is prepared by applying a solution of a second material containing a polymer (e.g., PVFD) at a concentration of up to about 20 wt. and an inorganic salt (e.g., LiCl) in a solvent (e.g., DMAc or a 50/50 mixture by volume of DMAc and NMP) on the porous first material. In another particular embodiment, the composite porous material is prepared by applying a solution of a second material containing a polymer (e.g. PVFD) at a concentration of about 5 wt. up to about 20 wt. and an inorganic salt (e.g., LiCl) in a solvent (e.g., DMAc or a 50/50 mixture by volume of DMAc and NMP) on the porous first material. In each of the specific embodiments of this paragraph, the product obtained therefrom is then contacted with a water-miscible liquid.

METHODS OF USING THE Porous Composite Material BY THE INVENTION [0110] The porous composite materials of the present invention find use in a variety of applications including filtration processes such as microfiltration, ultrafiltration and nanofiltration, but not limited to them. The materials of the present invention can also be used in microfiltration processes that are conducted at pressures higher than normal, i.e. pressures typically associated with ultrafiltration or nanofiltration processes.

[0111] Examples of applications for which microfiltration is suitable include dedusting, sterilizing cold drinks and pharmaceuticals, harvesting cells, purifying fruit juices, beer or wine, wastewater treatment, oil and water separation and continuous fermentation. Examples of applications for which ultrafiltration is suitable include pretreatment of seawater in desalination plants, purification of seawater, recovery of milk whey proteins and treatment of wastewater for reuse as process water. Examples of applications for which nanofiltration is suitable include reforming dyes and draining lactose from milk.

[0112] Also described is a liquid filtration method comprising passing a liquid through a composite porous material according to the invention.

[0113] Also described is a method of filtering liquids (e.g., water, seawater, wastewater, beverages) comprising passing the liquid through a composite porous material according to the invention.

[0114] Also described is a gas (e.g. air) filtration method comprising passing gas through a composite porous material according to the invention.

[0115] The following examples are summarized to aid in the understanding of the present invention and should not be construed as limiting specifically the invention described herein and claimed. Such changes to the present invention, including the substitution of all currently known or later developed equivalents that are within the field of view of a person skilled in the art, should be considered to fall within the scope of the present invention.

EXAMPLES

EXAMPLE 1: MANUFACTURE OF SOLUTION AND SECOND MATERIAL

[0116] Before applying the second material to the porous first material in accordance with the exemplary embodiment of the present invention, two separate chemical solutions, Intermediate Solution A and Intermediate Solution B were prepared and then combined into the Solution of Second Material I as follows .

INDIRECT SOLUTION A [0117] To a jar / bottle (milling jar / carboy) of a cylindrical mill, high density polyethylene ("HOPE"), with a capacity of one gallon (3.8 liters), 100 grams of lithium chloride (LiCl) and 2500 grams DMAc. The cylinder cover was secured with a protective tape and the cylinder was placed on the rollers of the roller mill operating at 20 rpm for 2 hours, after which time LiCl appeared to be completely dissolved. The bottle was opened and 520 grams of PVDF (KYNAR 2800 from Atofina Chemicals, Inc.) was added. PVDF was slowly combined with the solution, stirring with a glass rod to avoid air bubbles. The bottle cover was then secured with a protective tape and the bottle was placed on a roller mill at 20 rpm until a solution appeared homogeneous (after about 4 - 10 hours). Intermediate Solution A was tested for color (e.g. yellowish appearance), air bubbles and / or gel lumps of undissolved PVDF. Since none of these conditions was visible, the lid on the cylinder was secured with a protective tape and the cylinder was placed in a temperature-controlled room (maintained at about 25^aboutC) before further use.

INDIRECT SOLUTION B [0118] To another cylinder of a HOPE cylindrical mill with a capacity of one gallon containing 900 grams of NMP, 100 grams of PVP (type K-90 obtained from ISP Technology Inc. (Wayne, NJ)) were added. The set was mixed gently with a glass rod. The bottle cover was secured with a sealing tape and the bottle was placed on the mill at 20 rpm until Intermediate Solution B appeared, which appeared homogeneous (after about 4 - 10 hours). Intermediate Solution B was tested for color (e.g. yellowish appearance), air bubbles and / or gel lumps of undissolved PVP. Since none of these conditions was visible, the cylinder cover was secured with a protective tape and the cylinder was placed in a temperature-controlled room (maintained at about 25^aboutC) before further use.

SECOND MATERIAL SOLUTION I [0119] At a temperature of about 25^aboutC Intermediate Solution A was combined with Intermediate Solution B to form Second Material Solution I by adding Intermediate Solution A to the bottle containing Intermediate Solution B. The cylinder lid of Intermediate Solution B was secured with a protective tape and the cylinder was placed on a roller mill at 20 rpm until formed a solution that seemed homogeneous (after about 6 hours). The mill bottle and Second Material Solution I were removed for color and solid polymer particles. Since none of these conditions was visible, the cylinder cover was secured with a protective tape and the cylinder was placed in a temperature-controlled room (maintained at about 25^aboutC) before further use.

EXAMPLE 2: APPLYING A SECOND MATERIAL ON FLAT FIRST MATERIAL

[0120] Example 2 describes a non-limiting embodiment of the present invention in which a solution of a second material was applied to a porous flat substrate containing the first material. Each step described below was carried out at a temperature of about 25^aboutC.

[0121] A flat sheet of sintered porous PVDF with dimensions of 8 inches by 8 inches and a thickness of about 0.25 inches (0.64 cm) and with a porosity of about 40% and an average pore size of about 80 mm, obtained from Porex Corporation (Fairburn, GA) placed on a clean, flat, smooth, leveled glass table. Each corner of the sheet was attached to the table surface with insulating tape. Three layers of 0.75 inch (1.9 cm) wide insulating tape were placed on the table surface beyond each corner of the sheet. The thickness of the three layers of tape, approximately 0.015 inches (0.038 cm), corresponds to the desired wet thickness of the second material. [0122] A portion of the Second Material Solution I was poured from a jar into a 100 ml glass beaker. From this beaker, approximately 20 ml of Second Material Solution I was poured onto the sheet along a line about 2 inches (5.1 cm) from the corner of the sheet to form a roller. A glass rod with a diameter of 2 inches (5.1 cm) and a length of 8 inches (20.3 cm) was used as a squeegee to evenly spread the solution roller and to remove excess solution of the second material from the sheet. This was done by pulling the rod with its longitudinal axis parallel to the shaft, slowly from top to bottom (for about 30 seconds) and evenly over the sheet with pressure dropping along from the position outside the outer edge of the upper belt strip to the position outside the outer edge of the lower belt strip. When the removal of excess solution was completed, the timer was started immediately.

[0123] After 3 minutes, the insulating tape was cut at all four corners, releasing the coated sheet from the table. The sheet was held suspended for three minutes in a flat position with the coated side up, and then carefully transferred to a glass tray 12 inches long, 12 inches wide and 6 inches deep (30.5 x 30.5 x 15.2 cm) filled to about 4 inches (10 cm) of tap water. The sheet, coated side up, was then dipped evenly into a water bath for a period of about 10 seconds and held by hand for about 3 minutes. The sheet was then removed and allowed to lie flat on top of the tray for about 24 hours.

[0124] After removing the sheet from the tray, it was placed in another tray, as described previously, but containing a 5 wt.% Glycerin solution. in tap water for 30 minutes. After removing the sheet from the solution, it was air-dried for 24 hours. The obtained sheet of porous composite material had a porous substrate of a first material with an average pore size of about 80 mm and a porous membrane of a second material with an average pore size of about 0.1 mm. A piece of 7.5 inch by 7.5 inch (19.1 x 19.1 cm) PVDF sintered porous sheet weighed 240 grams before applying the Second Material Solution I. After drying, as described above, the weight of the porous composite sheet having these same dimensions made from it increased by 5 g.

EXAMPLE 3: APPLYING A SECOND MATERIAL TO THE VERTICAL ORIENTED PIPE

FIRST MATERIAL [0125] Example 3 describes a non-limiting embodiment of the present invention in which a solution of a second material was applied to a porous tubular substrate containing the first material. Each step described below was carried out at a temperature of about 25^aboutC.

[0126] A porous tube, obtained from Porex Corporation and formed from sintered PVDF, was used. The porous tube was 36 inches (91.4 cm) long and 1 inch (2.5 cm) in diameter and 1.330 inch (3.4 cm) in outer diameter.

[0127] Keeping the porous tube vertically above the beaker and the bottom hole of the tube clogged with a stopper to retain the solution, Second Material Solution I containing PVDF was poured into the tube and described in Example 1. After 15 minutes, excess solution was drained into the beaker and into the hole of the porous tube a 2.5 cm diameter stainless steel milled calibration ball was inserted to act as a squeegee for excess solution inside the pipe. Then, down the outer diameter of the pipe, a stainless steel slip ring with an inner diameter of 1.125 inches (2.86 cm) was manually pulled to act as a squeegee for excess solution outside the pipe.

[0128] While maintaining the vertical longitudinal axis of the coated porous tube, the tube was slowly immersed (in about 30 seconds) into a drum-like tub containing about 55 gallons (208 L) of tap water and allowing submersion under water until it touched the bottom of the tub. The tube was left in the bath for about 24 hours.

[0129] After removing the tube from the bath, maintaining the longitudinal axis of the coated porous tube vertically, the tube was immersed in a second bath containing a 5 wt% glycerin solution. in tap water for 30 minutes. After removing it from the bath, the tube was air-dried for about 24 hours. Before applying the Second Material Solution, Irura weighed 400 g. After drying, as described above, the weight increased by 15 g.

[0130] The obtained porous composite pipe had a porous substrate of a first material with an average pore size of about 80 mm and a porous membrane of a second material with an average pore size of about 0.1 mm. As can be seen, e.g. from FIGURES 2-10 discussed above, the porous membrane of the second material was in the pores of a porous substrate of the first material and the porous second material was connected to the walls of some pores of the porous substrate of the first material.

EXAMPLE 4: APPLYING A SECOND MATERIAL TO A LEVEL ORIENTED PIPE

FIRST MATERIAL USING THE TORPED APPLICATOR [0131] Example 4 describes a non-limiting embodiment of the present invention in which a solution of a second material was applied to a porous tubular substrate containing the first material by using an applicator with a bevelled or conical leading edge ("torpedo applicator"). Each step described below was carried out at a temperature of about 25^aboutC.

[0132] Torpedo Applicator: The torpedo applicator 10, as shown in FIGURES 11 and 12, was made of 304 grade stainless steel. The torpedo applicator 10 shown in FIGURE 11 had an overall length of I1 5.08 cm. Since the solution of the second material should be applied to the inner surface of the porous tubular substrate, the maximum diameter of the torpedo applicator 10 (2.489 cm) was determined by the diameter of the inner surface of the porous tubular substrate 26 (2.515 cm). The torpedo applicator 10 had a circular contact area of ​​the initial leading edge for insertion 12 and a circular contact area of ​​the leading edge of the overlap 14. The circular contact area of ​​the initial leading edge of the insertion 12 had an I2 length of 1.27 cm, and the circular contact area of ​​the leading edge of overlap 14 had a length I4 of 0.635 cm.

EP 1 687 133 B1

Each of the circular areas of contact surfaces 12 and 14 had a maximum diameter d1 and d2 of 2.489 cm, respectively, which, after introducing the solution, allowed the liquid pressure to build up against the inner surface of the porous tubular substrate 26 and produce a second material (not shown in FIGURES 11 and 12) with relatively uniform thickness, as discussed below. Adjacent to the circular contact area of ​​the initial leading edge 12, there was a conically shaped nose 16 having a length I5 of 0.635 cm. The conically shaped nose 16 allowed easy insertion and easy positioning of the torpedo applicator 10 inside the porous tubular substrate 26. Between the circular areas of the contact surfaces 12 and 14 there was a tank section 18 having a length I3 2.54 cm and constituting a depression relative to the circular areas of the contact surfaces 12 and 14 to a depth of 0.318 cm, i.e. walls 13 and 15 at the ends of the tank section 18 were 2.54 cm away, 0.38 cm deep each. Tank section 18 also had six liquid supply channels 20, each 0.318 cm in diameter, which were radially drilled through into the empty central chamber of the torpedo applicator 10. Liquid supply channels 20 were used to supply a solution of the second material to tank section 18, thereby providing contact of the inner surface of the porous tubular substrate 26 with the solution during the application process of the second material.

[0133] As shown in FIGURE 12, the end of the conically-shaped nose 16, further away from the circular contact area of ​​the initial insertion leading edge 12 has a cap including a liquid entry channel 22 drilled in the flat surface 24 of the conical-shaped nose 16. The liquid entry channel 22 having a depth of 3.81 cm provided access to the empty central chamber of the torpedo applicator 10 and was in fluid communication with the liquid supply channels 20. The liquid entry channel 22 was machined and threaded to obtain a state pipe thread (" NPT ") with a diameter of 0.125 inches (0.318 cm) to connect the threaded pipe (see FIGURE 12).

Applying a Second Material Solution to a First Tubular Material [0134] In the torpedo applicator 10 shown in FIGURE 11, also shown in FIGURE in a state connected to the fluid supply system used, controlled liquid pressure, i.e. a gravity driven pressure head, was applied to apply the second material solution on the inner surface of the porous tubular substrate of the first material. The solution flow rate was measured during application. The torpedo applicator 10 described above was shot on a seamless combination of the feed pipe / propeller 28 of 304 / 304L stainless steel (see FIGURE 13) having an I6 length of about 120 cm, which was longer than the porous tubular substrate 26 with a length of I7 91.4 cm, on which a second material solution was applied. The end of the steel tube 28 remote from the torpedo applicator 10 was connected to the first exit port P of the stainless steel ball valve 30 (shown in FIGURE 13 as the "T-shaped" ball valve). The ball valve 30 had an inlet 32 ​​and a second outlet 34. Both inlets 32 and a second outlet 34 were provided with a corrugated pipe coupling for connection to a HOPE pipe with an internal diameter of 1.588 cm. The inlet 32 ​​was in fluid communication with a 36 liter HOPE container 36 which contained a solution of the second material. The container 36 was mounted about 4.6 meters above the torpedo applicator

Ten. This liquid supply apparatus was used to deliver a Second Material Solution I, 26

EP 1 687 133 B1 containing PVDF as described in Example 1 and having a viscosity of about 500-10000 cps at a pressure of about 5 to 6 psi (34500-41300 Pa) to the torpedo applicator 10.

[0135] The torpedo applicator was carefully inserted into the hole at the end of the porous tube obtained from Porex Corporation and made of sintered PVDF, i.e. substrate 26. The longitudinal axis of the porous substrate was horizontally. The shorter length I1 of the torpedo applicator 10 relative to the length I7 of the porous tubular substrate 26 enabled the torpedo applicator to easily enter the opening of the porous tubular substrate.

[0136] Next, torpedo applicator was passed through steel pipe 28 through the length of substrate tube opening 26 until torpedo applicator 10 emerged from the other end of tube substrate 26 (as shown in FIGURE 11). The inner surface of tubular substrate 26 has, as such, been smoothed.

[0137] After the torpedo applicator 10 has been pulled back by means of the steel tube 28 back into the tubular substrate hole 26 so that the entire circular contact surface area 14 is inside the tubular substrate 26, while none of the circular contact surface areas 12 is inside the tubular substrate 26, delivery of the second material solution at a volumetric rate of about 70 ml / min to the torpedo applicator began. With the help of steel tube 28, torpedo applicator 10 was then once pulled through the opening of the porous tubular substrate 26 with an adjustable puller speed of about 30.5 cm / min, while the tubular substrate 26 was rotated around its longitudinal axis at 40 rpm by driven rollers the conveyor.

[0138] After the application of the solution to the interior of the tubular substrate was completed, after the torpedo applicator was completely extended from the tube, the coated porous tube, maintained with its longitudinal axis vertically, was slowly immersed (in about 30 seconds) into a drum-like tub containing about 55 gallons (208 l) of tap water and left to soak until it touched the bottom of the tub. The tube remained in the bath for about 24 hours.

[0139] After removing the tube from the bath, while still maintaining the coated porous tube with a longitudinal axis vertically, the tube was immersed in another bath containing a 5 wt.% Glycerin solution. in tap water for 30 minutes. After removing the tube from the bath, it was air-dried for 24 hours. Before coating with the Second Material Solution I, the tube weighed 400 g. After drying, as described above, the mass increased by 7 g.

[0140] The obtained porous composite pipe had a porous substrate of a first material with an average pore size of about 80 mm and a membrane of a second porous material with an average pore size of about 0.1 mm.

EXAMPLE 5: PREPARATION OF SECOND MATERIAL II SOLUTION [0141] A second solution was prepared as follows.

[0142] To a jar / bottle of HDPE cylindrical mill, 1 gallon, 470 grams of NMP, 322.55 grams of DMF and 102.5 grams of DMAc were added to form a solution. The solution was then gently mixed with a glass rod to avoid air bubbles, while 105 grams of PVDF (KYNAR 2800) were slowly added simultaneously. The cylinder cover was then secured with a protective tape and the cylinder was placed on a roller mill operating at 20 rpm until a solution was formed

Appearing homogeneous (after about 4 - 10 hours). The solution was then allowed to stand for about 16 hours at about 25^aboutC to remove air bubbles. The solution was then examined for color (e.g., yellowish appearance), air bubbles and / or gel lumps of undissolved PVDF. Since none of these conditions was visible, the lid on the cylinder was secured with a protective tape and the cylinder was placed in a temperature-controlled room (maintained at about 25^aboutC) before further use.

[0143] The Second Material Solution II was used instead of the Second Material Solution I to produce a composite porous tube in the procedure of Example 4 and provided similarly satisfactory results.

EXAMPLE 6: MANUFACTURE OF SECOND MATERIAL III SOLUTION [0144] Following the procedure used for Solution A in Example 1, a third solution was prepared as above, with the difference that 865 grams of NMP were used instead of 2500 grams of DMAc and 30 grams of LiCl and 105 grams of PVDF (KYNAR 2800). Second Material III solution was tested for color (e.g., yellowish appearance), air bubbles, and / or gel lumps of undissolved PVDF. Since none of these conditions was visible, the lid on the cylinder was secured with a protective tape and the cylinder was placed in a temperature-controlled room (maintained at about 25^aboutC) before further use.

[0145] Second Material Solution III was used instead of Second Material Solution I to form a composite porous tube in the procedure of Example 4 and provided similarly satisfactory results.

EXAMPLE 7: MANUFACTURE OF SECOND MATERIAL IV SOLUTION [0146] Following the procedure used for Solution A in Example 1 as above, a fourth solution was prepared, with the difference that 216 grams of NMP and 648 grams of DMAc were used instead of 2500 grams of DMAc and 30 grams of LiCl and 105 grams of PVDF (KYNAR 2800). Second Material IV solution was tested for color (e.g., yellowish appearance), air bubbles, and / or gel pellets of undissolved PVDF. Since none of these conditions was visible, the lid on the cylinder was secured with a protective tape and the cylinder was placed in a temperature-controlled room (maintained at about 25^aboutC) before further use.

[0147] Second Material IV Solution was used instead of Second Material Solution I to produce a composite porous tube in the procedure of Example 4, and provided similarly satisfactory results.

EXAMPLE 8: APPLICATION OF A SECOND MATERIAL TO VERTICAL ORIENTED PIPE

FIRST MATERIAL USING THE TORPED APPLICATOR [0148] The application process was carried out by a procedure similar to that described in Example 4 except that the longitudinal axis of the porous tubular substrate of the first material was oriented vertically rather than horizontally. The torpedo applicator was inserted into the upper end of the tubular substrate hole and moved through the length of the tubular substrate until the torpedo applicator appeared at the lower end of the porous tubular substrate. After starting to supply the second material solution to the torpedo applicator, the applicator was slowly moved up through the opening of the porous tubular substrate. When pulling up, the pressure of the second material solution was adjusted in the empty central space of the torpedo applicator chamber as needed to remain approximately constant.

EP 1 687 133 B1

EXAMPLE 9: APPLICATION OF A SECOND MATERIAL TO A LEVEL ORIENTED PIPE

FIRST MATERIAL USING THE TORPED APPLICATOR [0149] Example 9 describes a non-limiting embodiment of the present invention in which a solution of a second material was applied to a porous tubular substrate containing the first material. Each step described below was carried out at a temperature of about 25^aboutC.

[0150] A porous tube, obtained from Porex Corporation and formed from sintered PVDF, 91.4 cm long, 2.54 cm inner diameter and 3.81 cm outer diameter, plugged with a plug at one end. The tubular substrate was rotated so that its longitudinal axis was oriented vertically, with the plugged end pointing downwards. About 80 g of Second Material Solution I containing PVDF, as described in Example 1, was introduced into the bore of the tubular substrate until the tubular substrate was half filled up. Then the upper opening of the porous tubular substrate was plugged with a plug.

[0151] The resulting clogged tubular substrate was placed in a cylindrical handle with a solvent safety housing having a cylindrical hollow center with an internal diameter of about 5.08 cm, intended to hold the tubular substrate tightly after inserting an O-ring between the inner surface of the handle and the outer surface tubular substrate. The cylindrical holder was then placed on a horizontal roller mixer and rotated at a speed of about 40 rpm for about 3 minutes to allow the solution of the second material to be spread on the inner surface of the porous tubular substrate. Rotations were stopped and end plugs removed to allow residual solution of second material to drain from the pipe. A steel ball with a diameter of 2.50 cm and weighing 65 g was inserted into one end of the pipe. The pipe was then slowly lifted, allowing the ball to roll down into the pipe hole to squeeze out the residual solution of the second material and to ensure an even surface finish.

[0152] Holding the coated porous tube vertically with its longitudinal axis, it was slowly immersed (for about 30 seconds) into a tub-like tub containing about 55 gallons (208 L) of tap water and allowed to submerge until it touched the bottom of the tub. The tube was left in the bath for about 24 hours.

[0153] After removing the tube from the bath, while still maintaining the coated porous tube with its longitudinal axis vertically, the nucleus of another bath containing a 5 wt.% Glycerin solution was immersed. in tap water for 30 minutes. After removing the tube from the bath, it was air-dried for 24 hours. The tube weighed 400 g before coating with the Second Material Solution I. After drying, as described above, the weight increased by 10 g.

[0154] The obtained porous composite pipe had a porous substrate of a first material with an average pore size of about 80 mm and a membrane of a second porous material with an average pore size of about 0.1 mm.

EXAMPLE 10: APPLYING A SECOND MATERIAL TO A LEVEL ORIENTED PIPE

FIRST MATERIAL [0155] The application process was carried out in a procedure similar to that described in Example 9, except that the steel ball was replaced by a glass rod (107 cm long, 2.413 cm in diameter) inserted into the hole of the coated pipe substrate with its longitudinal axis parallel to longitudinal axis of the pipe. 29

EP 1 687 133 B1

The glass rod "slipped" downwards in the pipe hole, pushing the residual solution of the second material outwards and ensuring an even surface finish.

[0156] The present invention is not limited in its scope to the specific embodiments disclosed in the examples which serve as illustrations of certain aspects of the invention and any embodiments that are functional equivalents are within the scope of the present invention. Indeed, various modifications of the present invention, in addition to those shown and disclosed herein and will be understood by those skilled in the art, are considered to fall within the scope of the appended claims.

[0157] Many related materials are cited herein, the disclosure of which is incorporated herein in its entirety as a related material.