Fiber glass carrier having increased surface area and photo-active matrices formed therefrom

Description: TECHNICAL FIELD [Detailed description of the invention]

【0001】

(Citation of related patent application) This application claims the benefit of US Provisional Application No. 60 / 139,166 (filed June 15, 1999), and US Patent Application No. 09 / 183,570 entitled "Photocatalytic Filter with Fiberglass Matte Carrier". Related to issue (filed October 30, 1998). [0002]

(Background of invention) (1. Field of invention) The present invention relates to structures for utilizing known photoactive effects of specific materials (eg, photocatalytic materials and photoelectrostatic materials), and more specifically to photoactive materials on the surface of specific fiberglass carriers. Regarding the combination. [0003]

(2. Technical consideration) As used herein, the term "photoactive material" means a material that interacts with radiation and activity of a particular wavelength (eg, photocatalytic material and photoelectrostatic material). The term "photocatalyst" or "photocatalytic material", as used herein, means that when valence band electrons are exposed to photons of a given energy, they are promoted to the conduction band and in the charge electron band. Means a material in which corresponding holes are simultaneously generated. These electrons and holes are each consumed by reducing the electron acceptor adsorbed on the surface of the photocatalyst and oxidizing the electron donor. T. Sakata, "Heterogeneous Photocatalysis at Liquid-Solid Interfaces", Photocatalysis: Fundamentals and Applications, N. Serpone and See E. Pelizzetti (1989), pp. 311-313, which is incorporated herein by reference. As used herein, a "photoelectric material" is when a photon collides with an atom in the material with sufficient energy to remove an electron from a fixed position in the material. It means a material that can convert radiation (typically solar radiation) into electricity. See Van Nostrand's Scientific Encyclopedia, edited by D. Considine and G. Considine, (1989, 7th edition), pp. 2635-2636 (which is incorporated herein by reference). [0004]

The use of metal oxides (eg, titanium dioxide) for photocatalytically decomposing organic materials has been extensively processed in the prior art. In addition to titanium dioxide, photocatalytic effects have been reported to be achieved with oxides of zinc, tungsten, and tin. The present invention appears to be useful as any photocatalyst can be coated on the fiberglass. As the photocatalyst, several known photocatalytic non-oxidizing substances can be similarly mentioned, but since it is easy to weld a metal oxide by the current known technique, it is used on an elongated surface area substrate. Therefore, metal oxides are the preferred category. [0005]

In US Pat. No. 5,045,288, the layer of catalytic particles is loosely supported on the filter or in the granular bed. A more practical approach to using a photocatalyst is to coat the solid support membrane with a catalyst. For example, the use of a ceramic porous substrate to support a titanium dioxide coating is disclosed in US Pat. No. 5,035,784. The use of transparent substrates (eg, glass) has been suggested as the photocatalytic effect requires exposure of the catalyst to UV light. In particular, in U.S. Pat. Nos. 4,892,712; 4,966,759 and 5,032,241 (Robinson et al.), Fiberglass combines both transparency and high surface area, whereby carriers made from fiberglass matrices are: It has been recognized that it is ideally suited for this purpose. Robinson et al.'S patent discloses both woven and non-woven fiberglass substrates, but woven meshes are preferred, and details regarding non-woven embodiments are not provided. [0006]

In a similar fashion, it has been observed that the efficiency of photovoltaic cells can be improved by applying photoelectrostatic materials to rough or high surface area carriers. For example, Japanese Patent Application No. 58120459 discloses a solar cell containing an amorphous silicon thin film formed on a metal foil laminated on a cloth. This configuration is believed to improve battery conduction performance and conversion efficiency due to non-uniformity of the cloth and foil surfaces. [0007]

A high surface area carrier for use in forming the photoactive matrix, and in particular a non-woven fiberglass carrier with a high surface area, provided an increase in both the amount and contact area of the photoactive material incorporated therein. It is advantageous to make it possible. Moreover, this is advantageous when the surface area of the non-woven carrier can be further increased to provide a further level of performance enhancement in such applications. The uniquely processed fiberglass carrier meets these goals of providing a high surface area available, and this carrier is used directly to produce photoactive matrices for a variety of applications. It is found here that this surface area makes it possible. [0008]

(Gist of the invention) One aspect of the invention is a fiberglass carrier that includes a plurality of glass fibers, wherein at least a portion of the plurality of glass fibers is measured by BET surface area analysis using nitrogen. It has a surface area of at least about 10 square meters per gram. [0009]

Another aspect of the invention is an unwoven fiberglass carrier containing multiple glass fibers, at least a portion of the plurality of glass fibers having a high surface area silica material located on it. .. [0010]

Another aspect of the present invention is a method of forming a high surface area fiberglass carrier, wherein the method is a step of forming a fiberglass carrier containing a plurality of glass fibers, and at least of the plurality of glass fibers. Including the step of modifying at least a portion of the plurality of glass fibers so that some have a surface area of at least about 10 square meters per gram as measured by BET surface analysis using nitrogen. .. [0011]

Yet another aspect of the present invention is a method of forming a high surface area fiberglass carrier, in which the step of forming an unwoven fiberglass carrier and the high surface area silica material are woven. Includes the step of applying to at least a portion of the surface of a non-fiberglass carrier. [0012]

Yet another aspect of the present invention is a method of forming a photocatalytic matrix, which is a step of forming an aqueous dispersion containing a plurality of chopped glass fibers and a foaming agent, in which the dispersion is agitated. A step of forming a foamed slurry, a step of molding the foamed slurry to form a sheet, a step of removing at least a part of bubbles from the sheet, and a step of drying the sheet at least partially to form a fiberglass carrier. , And the steps of incorporating the photocatalyst material into the fiberglass carrier to form a photocatalytic matrix. [0013]

Another aspect of the present invention is a method of forming a photocatalytic matrix, which is a step of forming an aqueous dispersion containing a plurality of chopped glass fibers and a high surface area silica material, molding the dispersion. The sheet is formed by forming a sheet, the sheet is at least partially dried to form a fiberglass carrier, and a photocatalyst material is incorporated into the fiberglass carrier to form a photocatalytic matrix. [0014]

(Detailed description of the invention) The fiberglass carriers of the present invention are advantageous in providing a high surface area support for photoactive materials, and especially for photocatalytic and photoelectrostatic materials, which are formed from this support. It may provide enhanced performance of the photoactive matrix. As used herein, the term "photoactive matrix" means a fiberglass carrier with a photoactive material incorporated therein. Although not meant to be limited in the present invention, preferably the photoactive material is by applying a coating containing the photoactive material to at least a portion of the surface of the carrier after the formation of the carrier, or at least a portion of the surface. It is incorporated into the carrier by incorporating at least one fiber coated with a photoactive material into the carrier, or by incorporating the photoactive material into the carrier during carrier formation. Methods of incorporating photoactive materials into the carriers of the present invention are discussed in detail below. [0015]

With reference to FIGS. 1 and 1a, in one non-limiting embodiment according to the invention, preferably the fiberglass carrier 10 is formed from a plurality of glass fiber strands 12, including a plurality of individual fibers or filaments 14. To. As used herein, the term "strand" means a plurality of individual fibers, and the term "fiber" means an individual filament. [0016]

Fiberglass strands 12 can consist of fibers 14 formed from known glass compositions based on silicon oxide selectively modified with other oxides and non-oxidizing compounds. Useful glass fibers can be formed from any type of fibrous glass composition known to those skilled in the art, and "E-glass", "A-glass", "C-glass", "D-glass". , "R-Glass", "S-Glass", and glass fibers prepared from fibrogenic glass compositions commonly known as E-glass derivatives. As used herein, "E-glass derivative" means a glass composition containing a small amount of fluorine and / or boron, and preferably does not contain fluorine and / or boron. Further, as used herein, a small amount means less than about 1% by weight fluorine and less than about 5% by weight boron. Preferred glass fibers are formed from E-glass or E-glass derivatives. Such compositions and methods of making glass filaments from these compositions are well known to those of skill in the art, and further discussion of them is not considered necessary in the light of the present disclosure. If more information is needed, such glass compositions and methods of fiberization are described by K. Loewenstein, The Manufacturing Technology of Continuous Glass Fibers (3rd Edition, 1993), pp. 30-44, 47-60. Pages 115-122 and 126-135; and US Pat. Nos. 4,542,106 and 5,789,329, which are incorporated herein by reference. [0017]

Glass fibers are made with an apparent filament diameter in the range of about 3.5 micrometers to about 35.0 micrometers (microns), and any filament diameter can theoretically be used in the present invention. Even smaller filament diameters are possible, especially with spun fiberglass. Although not required, an apparent filament diameter greater than 3.5 microns should be used to avoid the presence of breathable fibers (eg, if the photoactive matrix is a photocatalytic matrix for use in air filtration applications). It is preferable to use the fiber having. Moreover, filament diameters smaller than 7 microns are not readily available on the market. Thus, in one non-limiting embodiment of the invention, most glass fibers in fiberglass carriers have an apparent filament diameter of at least about 1.0 micron, and preferably at least about 3.5 microns. In other specific non-limiting embodiments of the invention, most fibers have an apparent filament diameter of about 10 microns. Larger diameters, on the order of 17 microns and above, can also be considered for use in the present invention and may have the advantage of being easy to process. However, the filament diameter is not important in the present invention. See Loewenstein (supra), page 25, which is incorporated herein by reference for further information regarding the designation of apparent filament diameters and glass fibers. [0018]

The individual filaments are usually assembled together to form a strand. The number of filaments per strand can range from about 100 to about 15,000, and typically from about 200 to about 7000. For more information on the designation of fiberglass strands, see Loewenstein (supra), page 27, which is incorporated herein by reference. [0019]

To prevent destructive peeling between filaments during processing, glass fibers have traditionally coated at least a portion of this surface with a sizing composition, which lubricates the fibers and binds the filaments to the strands. It works as it does. Traditionally, most sizing compositions contain a polymer film-forming material as their most abundant organic component. Most conventional sizing compositions also contain coupling agents, lubricants, and surfactants. Other small amounts of additives (eg, antistatic agents) may also be present. To minimize the organic content of fiberglass, the present invention uses sizing compositions that contain little or no material that would normally predominantly form a film. This does not mean that film formation does not occur with the remaining components. In particular, it is believed that the coupling agent, when present, produces some degree of film formation, but does not produce an elastomeric form (conventional film-forming agents are selected for this purpose). In one non-limiting embodiment of the invention, a relatively brittle film is not considered disadvantageous. This is because such a film assists in the filamentation of the strands that occurs in the subsequent matting process. As used herein, the term "filamentization" means opening a bundle of strands and separating them at least partially into individual filaments or fibers. Filamentization is advantageous because it increases the surface area of the carriers and provides greater opportunities for mechanical twisting of the filaments. In one embodiment of the invention, but not limited to, the sizing component is selected primarily for its lubricating function, and thus preferably comprises a conventional lubricant. Coupling agents can also act as a lubricating function, whereby the sizing composition of the present invention may contain a coupling agent in place of or in addition to conventional lubricants. [0020]

At least one of the glass fiber lubricants is included in the sizing according to one non-limiting embodiment of the present invention, and is different from what is conventionally considered to be a polymeric film-forming material. Glass fiber lubricants may have some film-forming ability, but are otherwise not selected for this purpose. Useful glass fiber lubricants include, but are not limited to, cationic lubricants, nonionic lubricants, or anionic lubricants, and mixtures thereof. The fiber lubricant may make up 0-100% by weight of the sizing composition on the basis of an all-solid state. Preferably, although not required, a combination of lubricant and coupling agent can be used, in which case the lubricant is present in an amount of 1-20% by weight based on the whole solid of the sizing composition. Can be done. Non-limiting examples of many known fiber lubricants include amine salts of fatty acids (eg, fatty acid moieties having 12-22 carbon atoms and / or alkyl groups of 1-22 atoms becoming nitrogen atoms. 4 ~, such as attached tertiary amines), alkylimidazoline derivatives (eg, those that can be formed by the reaction of fatty acids with polyalkylene polyamines), acid solubilized fatty acid amides (eg, stearic amides). From saturated or insoluble fatty acid amides with 24 carbon atom acid groups, condensates of fatty acids, polyethyleneimines and amine-substituted polyethyleneimines (eg, EMERY® 6717, Henkel Corporation, Cincinnati, Ohio) Commercially available, partially amidated polyethyleneimine). [0021] [0021]

Useful alkyl imidazoline derivatives, but not limited to, in the present invention include CATION X from Rhone Poulenc, Princeton, New Jersey and LUBRIL CAT-X / VC from Rhodia, Cranbury, New Jersey. Other useful non-limiting lubricants are commercially available from Borden Chemical, Louisville, Kentucky, RD-1135B epoxidized polyester, CIRRASOL 185A fatty acid amide, Akzo Chemicals, Inc., Chicago, Illinois. Examples include the partially carboxylated polyester KETJEN LUBE 522 and the high density polyethylene emulsion PROTOLUBE HD commercially available from Hybrid Chemicals, Birmingham and New Jersey. [0022]

Non-limiting examples of coupling agents that can be contained in the sizing compositions of the present invention include organic silane coupling agents, transition metal coupling agents (eg, titanium, zirconium and chromium coupling agents), amino-containing Werner cups. It can be selected from the group consisting of ringing agents and mixtures thereof. These coupling agents typically have a double functional group. Each metal or silicon atom is deposited with one or more groups that can react with the glass fiber surface or are chemically attracted in other ways but do not necessarily have to be attached to the glass fiber surface. .. Traditionally, other functional groups contained in the coupling agent provide reactivity or adaptation with the film-forming polymer. This functional group is of lesser importance, as conventional film-forming polymers are independent in the present invention. However, some self-crosslinking ability with some coupling agents may be provided by additional functional groups. [0023]

Although not required, organic silane compounds are preferred coupling agents in the present invention. Non-limiting examples of suitable organic silane coupling agents are Z-6040 γ-glycidoxypropyltrimethoxysilanes commercially available from Dow Corning, Midland and Michigan; respectively from CK Witco Corporation, Tarrytown and New York. Examples thereof include commercially available A-187 γ-glycidoxypropyltrimethoxysilane, A-174γ-methacryloxypropyltrimethoxysilane and A-1100 γ-aminopropyltriethoxysilane. Although not limited in the present invention, the amount of coupling agent can be 0-80% by weight of the sizing composition based on the all-solid state. In a preferred non-limiting embodiment, the content of the coupling agent is at least 10% by weight, and more preferably at least 30% by weight, of the sizing composition, based on the all-solid state. Although not required, the organic silane coupling agent can be hydrolyzed at least partially with water prior to application to the glass fiber. [0024]

One non-limiting embodiment of the sizing composition may contain one or more surfactants for stabilizing other components of the sizing composition in an aqueous medium. Non-limiting examples of suitable surfactants are polyoxyalkylene block copolymers (eg, PLURONIC commercially available from BASF Corporation, Parsippany, New Jersey).^TM F-108 polyoxypropylene-polyoxyethylene copolymer), alkylphenol ethoxylated (eg, IGEPAL CA-630 ethoxylated octylphenoxyethanol commercially available from GAF Corporation, Wayne, New Jersey), polyoxyethylene octylphenyl glycol ether, sorbitol. Ethylene oxide derivatives of esters and polyoxyethylated vegetable oils (eg, EMULPHOR EL-719, also commercially available from GAF Corp.). Generally, the amount of surfactant can be 0-40% by weight of the sizing composition, based on the whole solid. [0025]

Although not required, small amounts of various additives (eg, antistatic agents, fungicides, fungicides, and antifoaming materials) may also be present in the sizing. Also, organic and / or inorganic acids or bases may be contained in the sizing composition in an amount sufficient to provide an aqueous sizing composition having an appropriate pH (typically 2-10). [0026]

When applied to glass fibers, the sizing composition is preferably diluted with water to several times its weight. The amount of water (preferably deionized water) contained in the sizing composition can be any amount sufficient to facilitate the application of a nearly uniform coating to the fiberglass. Although not limited in the present invention, the solid weight% of the sizing composition can generally range from about 5% to about 20% by weight, but the dilution of the sizing is such as the type of applicator used. It can vary significantly depending on the factors. [0027]

In one non-limiting embodiment of the invention, the sizing was made as follows: [0028]

[table 1]

<img file="JP2003519002A_D0001.tif" />Ingredients 4 and 5 were premixed by stirring for 20 minutes before adding to the other ingredients. Ingredients 6 and 7 were premixed by stirring for 20 minutes before adding to the other ingredients. [0029]

In one non-limiting preferred embodiment of the invention, the sum of all organic components of the sizing composition described above is minimized to avoid the need to heat treat the fiberglass carriers. In general, but not limited, the loss (LOI) in combustion of fiberglass carriers is less than 1.0% by weight, preferably less than 0.5% by weight, and most preferably less than 0.4% by weight. Although some sizing is preferably present, its components are selected to minimize LOI, as described above. In those preferred but non-limiting examples where some sizing is present, the LOI of the carrier is at least 0.1% by weight. [0030]

As used herein, the term "loss in combustion" or "LOI" means% by weight of the dry coating composition present in the carrier as determined by the formula 1 below: LOI = 100 × [(W_Dry-W_naked) / W_Dry)] (Equation 1) Where W_DryIs the weight of the fiberglass carrier and the weight of the coating composition after drying in the oven for 60 minutes at 220 ° F (about 104 ° C), and W_nakedIs the weight of the bare fiberglass carrier after heating the carrier in an oven at 1150 ° F (about 621 ° C) for 20 minutes and cooling to room temperature in a desiccator. [0031]

The sizing can be applied to the filaments of the invention by any of a variety of methods known in the art. These methods are, for example, not limited to them, by contacting the filament with a static or dynamic applicator such as a roller or belt applicator, or by spraying or other means. .. See, for example, Loewenstein (supra) pp. 165-172 for consideration of suitable applicators. This is incorporated herein by reference. The sized filament can be collected together into the strands as previously discussed. [0032]

Although not required, the sizing strands can be dried at room temperature or high temperature to remove moisture content and cure any curable sizing or secondary coating composition that may be present. Drying of glass fiber strands is customary in the art, and further details can be found in Loewenstein (supra) pp. 219-222. This document is incorporated herein by reference. [0033]

Although not a preferred embodiment for the present invention, the secondary coating can be applied to the strands. When used, preferably the secondary coating composition is water-based and may contain components similar to the sizing composition described above. The secondary coating composition may be applied to at least a portion of the surface of the strand in an amount sufficient to at least partially coat or impregnate the portion of the strand. This secondary coating has traditionally been done by immersing the strand in a bath containing the composition, by spraying the composition onto the strand, or statically or dynamically, for example, as a roller or belt applicator. It can be applied by contacting a suitable applicator with its strands. The coated strands can be passed through a die to remove excess coating from the strands and / or dried for a time sufficient to dry and cure the secondary coating at least partially as described above. Will be done. Although not required, when used, preferably the secondary coating has a composition similar to that of the sizing composition described above. [0034]

The process of making fiberglass and the process of forming it into a substrate or carrier are well known in the art and are not themselves part of the invention. Therefore, any conventional means of performing these steps can be used and does not need to be described in detail. The description of the fiber forming and substrate forming steps herein is not intended to limit the types of processes that can be used, but rather merely examples included for the purpose of disclosing the best embodiments of the present invention. Is. If desired, further details of these conventional aspects of the invention can be found in Loewenstein, 13-14, 18-19, 115-235, 293-312 and 322-324. This is incorporated herein by reference. [0035]

With reference to FIG. 1 again, the fiberglass carrier 10 of the present invention can be formed by any conventional method for forming a fiberglass substrate well known in the art. This method includes weaving methods well known in the art. However, although not limited in the present invention, the fiberglass carrier is preferably a non-woven carrier. As used herein, the term "non-woven" carrier means a carrier formed by a process other than the weaving method. Examples of suitable non-woven carriers include, but are not limited to: air-laid mats and wet raid mats. These are described in detail below. Other than the non-woven carriers suitable for use in the present invention, they include, but are not limited to: chopped strand mats and continuous strand mats. [0036]

Although not required, the use of non-woven fiberglass carriers is preferred in one non-limiting embodiment of the invention. The use of non-woven carriers is considered to be advantageous over the use of woven carriers, which tend to have a higher surface area available for deposition of the photoactive material on it. Nevertheless, in another non-limiting embodiment of the invention, the use of woven glass carriers with increased surface area is contemplated. The increase in surface area, but not limited to in the present invention, can be achieved in the woven carrier, for example, by needling, etching and / or applying a high surface area silica material to the carrier, as detailed below. [0037]

Referring again to FIG. 1, in one non-limiting embodiment according to the present invention, preferably the fiberglass carrier 10 is formed from a plurality of strands 12 and 14. These strands and fibers are chopped by a chopper to discontinuous lengths. [0038]

To facilitate the manufacture of the carrier 10 and to facilitate the interlocking of the filament 14, the chopped strands 12 and fiber 14 should have an average length of at least about 2 cm, but not in the present invention. Have, and generally do not exceed about 10 cm. Shorter lengths are generally difficult to convert into structurally incorporated mats, and longer lengths are difficult to process in the mat forming process. A chopped length of about 5 cm has been successfully used, and some strength benefits can be achieved with slightly longer lengths on the order of about 7-8 cm. Commercially available choppers are suitable (eg, Model 90 choppers from San Fernando, Finn and Fram, Inc., California). Devices and processes useful for forming layers of chopped strands are disclosed in Loewenstein (supra), pp. 293-303, which is incorporated herein by reference. [0039]

To provide high surface area in the photoactive matrix of the present invention, the fiberglass strands 12 are at least partially filamentized, as shown in FIGS. 1 and 1a. In one non-limiting embodiment of the invention, the glass strand 12 is preferably at least 70% by weight filamented, more preferably at least 80% filamented, and most preferably at least 90% filament. It has been transformed. 100% filamentation is optimal, but rarely achieved completely. Filamentization itself is known in the art and can be achieved by mechanical or pneumatic means typically associated with the mat forming apparatus. A non-limiting example of such a device, which favorably imparts a high degree of filamentation to its strands, is the RANDO-OPENER BLENDER, which is the Rando Machine Corporation of Macedon, It is a part of the MODEL B RANDO-WEB (registered trademark) processor marketed by New York. Alternatively, the strand opener can be a card machine (eg, commercially available from: Hollingsworth on Wheels, Inc. of Greenville, South Carolina or N. Schlumberger (USA) Inc. of Charlotte, North Carolina). The opening action of the Rando model is the agitation caused by passing the strands between a series of rolls rotating in opposite directions. The percentage of strands filamentized can be adjusted by adjusting the space between the opposing rolls of the strand opener and the rotational speed of that roll. [0040]

After the opening process, the fibers 14 and strands 12 can be transported to an air mat forming apparatus. A non-limiting mat former is RANDO-WEBBER®, which is part of the MODEL B RANDO-WEB® processor described above. In the Rando process, the glass fibers and strands are carried by airflow, and the fibers and strands are deposited on the surface of a rotating cylindrical feedmat condenser screen that is maintained at a pressure below atmospheric pressure to form a feedmat. The feedmat is scraped from the feedmat condenser and sent to the licker-in, which combs the individual strands and monofilaments from the feedmat, which is then placed in another air stream to atmospheric pressure. It is deposited as a mat on the surface of another rotating cylindrical capacitor screen that is maintained at less than pressure. The mat thus formed is transported from the mat former to the needling station. [0041]

Traditional mats are sometimes mixed with small amounts of one-way glass fiber, thermoplastic fiber and / or fabric. The purpose of these additional fibers is to provide the mat with transient strength during additional processing steps. These supplementary strands and / or fabrics can be located between layers of the mat or on one side of the mat and then subjected to a needling operation. Although not excluded by the present invention, these supplementary layers have not been found to be necessary in the preferred embodiments of the present invention. It is worth noting that the mechanical strength of the mats of the present invention can be achieved without such reinforcing strands or fabrics. [0042]

In one non-limiting embodiment of the invention, the glass fibers 14 and strands 12 (and any supplementary fibers) of the carrier 10 are intermeshed by subjecting the carrier 10 to the needling process. This needling can be achieved using conventional needling devices such as those used in the fiberglass reinforcement industry. Here, the carrier passes between the spaced needling boards. An example of such a device is disclosed in US Pat. No. 4,277,531, which is incorporated herein by reference. An example of one suitable needling machine is the Model NL 9, which is the German Textilmaschinenfabrik Dr. Commercially available from Ernest Fehrer AG. In the needling operation, a series of thorny needles are used to entangle or knit the monofilaments and strands of the mat to impart mechanical strength and integrity to the mat. As shown in FIG. 1, the effect of its needling is to move the filament 14 and / or part 16 of the strand 12 away from the carrier 10 of the generally parallel array and in a direction substantially vertical to the plane of the carrier 10. Is to put. The extent to which this arrangement occurs depends on factors such as the type of needle used, the depth of passage of the needle through the mat and the density of the needle holes. [0043]

In one non-limiting embodiment of the invention, the needling operation may use a needle constructed with a thorn bent towards the tip of the needle, whereby the fibers and strands in the mat are Tangles as this needle progresses into the mat. In the turning motion, this needle mold generally emits fibers. Needles with downward thorns are preferred, but the use of reverse thorn needles (ie, bending away from the tip of the needle) is not excluded from the present invention. It has been found that it is preferable to use relatively fine needles due to the low density of the mats of certain non-limiting embodiments of the present invention. As used herein, the term "low density" means, with respect to mats, a density of no more than about 1.0 ounce per square foot (about 305.1 g per square meter), and more preferably about about per square foot. It is less than 0.5 ounces (about 152.6 g per square meter). Needles with gauges heavier than 25 gauge (ie, smaller gauge numbers) tend to break an unreasonable number of filaments, thereby not improving the intended strength. Although not required, 30 gauge and lighter gauge needles, and preferably 32 gauge and lighter gauge needles, are recommended for use with the low density mats of the present invention. A particularly useful commercially available needle mold is a "star" shaped needle with six thorns spaced in a triangular arrangement around the shaft of the needle, which are paired with each other in the above vertical arrangement. Has thorns. It is also advantageous that the "star" shaped needle is placed on the thorn near the tip of the needle, as it has been found that it is preferable to limit the depth of the needle hole. Suppliers of these types of needles include: Foster Needle Company, Manitowoc, Wisconsin and Groz-Beckert USA, Charlotte, North Carolina. [0044]

As used herein in the description of the needling operation, the term "horizontal" or "horizontally" refers to a plane that is approximately parallel to the main plane of the mat. The main plane is typically parallel to the ground. As used herein, the terms "vertical" or "vertically", "downward" and "upward" refer to directions that are approximately "vertical" with respect to "horizontal". These specific directional terms are used to describe the needling operation for convenience, to reflect the normal orientation of the needling device, and to define the relative orientation to each other. However, it should be understood that these directions are not limiting in the process. [0045]

In a non-limiting embodiment, upon entering the needling operation, the needle held in the needle board passes through the mat and into the nearly columnar orifice in the backer board supporting the mat. Depending on the depth of the needle, one or more rows of thorns pass through the mat completely and enter the backerboard orifice. For the purposes of one non-limiting embodiment of the invention, when a two-row needle design is used, it is preferred that the thorns in both rows pass through and beyond the mat. The distance that the needle crosses the mat and enters the orifice of the backer board is referred to as the "kneading depth". The needling depth in the preferred non-limiting embodiment is 0.45 ~. It ranges from 65 inches (1 cm to 1.7 cm). [0046]

During the backtracking motion, after the needles exit the mat, they pass through multiple nearly cylindrical orifices in a metal stripper plate spaced from the mat during the needling process. The filaments and strands are pulled out of the thorns by a stripper plate, and the mat then proceeds after the complete movement of insertion and withdrawal of the needle. Although not required, the needle board can be reciprocated at a frequency of about 80 to about 3000 movements per minute. The needling device is typically provided with a roll to propel the mat in the horizontal direction during the needling. At slower frequencies, the progression occurs intermittently in the spacing between the needle holes. At higher frequencies, the progression approaches continuous motion. [0047]

The density of the holes can also be changed to affect the reinforcement of the mat. The density of needle holes depends on the particular type of needle used, the thickness of the mat and other factors. Although not limited in the present invention, in the context of other preferred needling parameters disclosed herein, the density of needle holes is preferably 100 to about 160 holes per square inch (1 square). It ranges from 15 to 25 holes per cm). Smaller hole densities are possible, but may not achieve the desired mat strength without a binder (discussed below). Larger hole densities at some point tend to produce reduced returns and, in fact, reduce mat strength. A preferred non-limiting embodiment used about 140 holes per square inch (23 holes per square cm). The needling process is described in more detail in US Pat. No. 4,335,176, which is incorporated herein by reference. [0048]

In a typical needling process, the mat entering the needling device can have an overall average thickness of about 5 to about 30 mm. After the currency of the needling device, the mat can have an average compression thickness of about 2.5 to about 7 mm. The thickness or "loft" of the mat is affected by the extent to which the fiber spikes extend from the surface of the mat due to the needling process. In certain non-limiting embodiments of the invention, the loft of the mat is relatively high for its low density. The loft in a preferred non-limiting embodiment of the mat of the present invention is greater than 0.25 inch (6.3 mm) and preferably greater than 0.35 inch (8.9 mm). Although not required, maximizing loft is generally "desired, but achieving lofts greater than about 0.5 inches (about 12.7 mm) with the types of mats included herein. May require excessive needling, which can have a detrimental effect on tensile strength. Lofts can be placed at a weight of 1 ounce per square foot and by measuring the thickness of the compression mat. Can be measured. [0049]

The tensile strength of carriers made from the air-laid process described above is 3 inches (7.6 cm) x 9 inches (22.9 cm) (22.9 cm) of mats pulled in their long dimensions using the Instron Series IX Materials Testing System. ) Was measured using the sample. Although not required in the present invention, preferably the mat carrier is more than 8.0 pounds per linear foot width of the mat (about 11.9 kg per linear meter), and more preferably 10.0 pounds per linear foot width of the mat (about 11.9 kg per linear meter). Shows greater tensile strength (about 14.9 kg per linear meter). [0050]

After the fiberglass 10 is formed, it can be treated to further increase the surface area of the fibers and strands, and / or carriers and coatings containing photoactivating materials are applied therein, as described in detail below. Can form a photoactive matrix. [0051]

In another non-limiting embodiment of the invention, fiberglass carriers are formed using a wet-laid papermaking process. Wet raid processes are well known to those of skill in the art, and the following examples are exemplary wet raid processes, but this is not construed as a limitation in the present invention. [0052]

In one non-limiting example of a method of forming a fiberglass carrier via a conventional wet-laid process, a chop glass fa dispersing Iba strands into white solution. As used herein, the term "white aqueous solution" refers to a solution, preferably an aqueous solution. The white aqueous solution may contain dispersants, thickeners, softening and curing chemicals, and dispersed or emulsified polymers. Such white aqueous solutions are well known in the art. If more information is needed, see U.S. Pat. No. 5,393,379, which is incorporated herein by reference. After dispersing the chopped glass fiber strands in a white aqueous solution, the dispersion or slurry is headboxed. Box) and then cast onto a moving wire screen to form a fiberglass sheet. As used herein, the term "cast" means deposition. The sheet is then at least partially dried by a suction device or decompression device to form fiberglass carriers. As discussed in detail below, after the fiberglass carriers have been formed, the fiberglass carriers can be processed to further increase the surface area of the fibers and / or carriers, and coatings containing photoactive materials, It can be applied to fiberglass carriers to form a photoactive matrix. [0053]

In another non-limiting embodiment of the method of forming a fiberglass mat carrier according to the present invention, this is the preferred method of forming a fiberglass mat carrier using a wet raid process, the carrier being one or more. It is formed by dispersing chop glass fibers with a foaming agent into an aqueous slurry and stirring the slurry to form bubbles. A non-limiting example of a suitable foaming agent for use in the present invention is TRITON X100, which is an ethoxylated octylphenol commercially available at Union Carbide Corporation of Danbury, Connecticut. If not necessarily required, but desired, the polymeric material can be dispersed in the aqueous slurry with chop fiber strands and foaming agent to bond with the carriers after drying. [0054]

After forming the foamed slurry, the slurry is cast on the web and the foam is depressurized and extinguished so that the fiberglass sheet remains. The fiberglass sheet can then be at least partially dried to form fiberglass carriers during the formation of the non-woven mat. As discussed in detail below, after the fiberglass carriers have been formed, the fiberglass carriers can be processed to further increase the surface area of the fibers and / or carriers, and coatings containing photoactive materials Can be applied to fiberglass carriers to form a photoactive matrix. [0055]

Not meant to be limited in the present invention, but a foamed slurry process that forms fiberglass carriers (which is also Radlite).^TMKnown as a process) is considered to be advantageous in that at least a portion of the chopped glass fiber strands is opened and at least partially filamentized during the stirring process. As discussed earlier, by opening the fiberglass strand bundle, the individual filaments are exposed thereby, providing a surface area on which the photoactive material can adhere. Moreover, if the photoactive material is incorporated into the dispersion prior to casting, an essentially uniform distribution of the photoactive material in the carriers can be achieved. Methods of incorporating photoactive materials into the carriers of the invention to form a photoactive matrix according to the invention are discussed in more detail below. [0056]

If desired, a binding material (or binder) may be applied to the carrier 10 after being formed to improve carrier integrity prior to treatment with a photoactive material. Non-limiting examples of organic binders considered useful in the present invention include polyvinyl alcohol, polyvinyl acetate, carboxymethyl cellulose and starch. However, in one non-limiting embodiment of the invention, here the fiberglass carriers of the invention are used to form a photocatalytic matrix, which carriers preferably have a low organic content. Carriers with low organic content are generally desirable for use in photocatalytic matrix applications. This is because the organic material is decomposed during the photocatalytic process. Therefore, when the photocatalytic material is applied over the organic coating layer, the organic layer can be decomposed and the adhesion of the photocatalyst is reduced. Moreover, if the structural integrity of the carrier depends on the organic material, the carrier itself can be degraded during the photocatalytic process. Therefore, when the organic binder is applied to the carrier, it is preferable to use the minimum amount of the organic binder required to achieve the desired operating and processing features. Where a binder is preferably utilized, it is not limited in the present invention, but this binder may replace or in addition to the conventional organic binder material discussed earlier, or in addition to one or more that may be essentially converted to an inorganic material. Includes organic materials. For example, but not limited to in the present invention, the matt binder may include one or more organometallic oxide chelates and / or one or more metal alkoxides. Specific non-limiting examples of preferred organometallic chelates are disclosed in US Pat. No. 5,908,497 (which is incorporated herein by reference). [0057]

It does not mean to be bound by any particular theory, but is good by using alternatives to the more conventional organic matte binders or, in addition, organic materials that can be converted to essentially inorganic materials. It is believed that fiberglass carriers with completeness and low organic content can be obtained, for example, by removing organic components from the carriers by heat treatment. During the heat treatment, such organic materials can be decomposed and converted to inorganic compounds (eg, oxides, nitrides, and carbides) to give carriers with good completeness and low organic content. [0058] [0058]

Methods of modifying at least a portion of the fiberglass of a fiberglass carrier to increase the surface area of the glass fibers and carriers of the present invention are generally discussed here. Referring again to FIG. 1, in one non-limiting embodiment according to the present invention, the fiberglass carriers 10 are subjected to an etching process prior to coating the carriers with the photoactive material, and the plurality of glass fibers 14 of the carriers 10 and Modify the surface area of at least a portion 20 of strand 12. As discussed previously, but not limited to the present invention, the carrier 10 can be formed by any method known in the art for forming carriers, and the air-laid process described above or It is preferably formed by a wet raid process. [0059]

The etching process of the present invention is believed to include removing ions from the surface of the glass to roughen the surface 18 of the glass fiber 14 and strand 12, thereby increasing the surface area of the fiber 14 and strand 12. The carrier 10 is then made from it. In the case of E-glass fiber, ions (eg, calcium ions, magnesium ions, iron ions, aluminum ions, and sodium ions) are believed to be removed from the glass surface during the acid etching process. The remaining material is predominantly silicon dioxide. See B. Ramachandran et al., "Effect of Organic Acids on E-Glass Fabric" Communication of the American Ceramic Society, (September 1981) C122-C pp. 124 (which is incorporated herein by reference). That thing. [0060]

Although not meant to be bound by any particular theory, by increasing the surface area of the glass fiber available for deposition of the photoactive material, the overall wider loading of the photoactive material is such high. It is believed that this can be achieved for carriers that incorporate surface area fibers. In one particular non-limiting embodiment of the invention, the photoactive material is here selected from the group of photocatalytic materials containing titanium dioxide, a further advantage of the etched fibers of the invention is the alkali content of the glass. Is to decrease. Such alkaline materials can react with the photocatalyst (or break the photocatalyst) to form compounds with reduced photocatalytic activity. For example, calcium cations can react with titanium dioxide photocatalytic material to form calcium titanate compounds with reduced photocatalytic activity. [0061]

Etching agents useful in the present invention include, but are not limited to, inorganic acids (eg, hydrochloric acid, nitric acid, sulfuric acid) and organic acids (eg, acetic acid and oxalic acid). In a preferred embodiment of the present invention, the etching agent is hydrochloric acid. [0062]

The carrier can be etched in any fashion known in the art. For example, without limiting the invention, the carrier can be etched by submerging it in an acid bath, or the acid can be applied to the surface of the carrier and later removed by rinsing. Preferably, the carriers are submerged in the acid for a period of time sufficient to bring about the desired level of etching, but not limited to those herein. In one embodiment according to the invention, the etching agent used herein is 2N hydrochloric acid at about 70 ° C., preferably the etching time is less than about 90 minutes, more preferably about 30 minutes. Less than, and most preferably less than about 10 minutes. [0063]

It will be understood by those skilled in the art that the desired etching can occur by adjusting both the temperature and concentration of the etchant. Increasing the temperature and / or concentration of the etchant can reduce the time required to achieve the desired etch. Preferably, but not necessarily required, the concentration and temperature of the etchant is adjusted to result in an etching time of less than about 10 minutes. [0064]

With reference to FIGS. 1 and 1a again, when measuring at least a portion 20 of the plurality of glass fibers 14 and strands 12 of the carrier 10 of the present invention by BET surface area analysis using nitrogen, but not limited to the present invention. Etch to have a surface area of at least about 10 square meters per gram, preferably at least about 50 square meters per gram, more preferably at least about 100 square meters per gram, and most preferably at least about 250 square meters per gram. BET surface area analysis is well known in the art, and further discussion is not considered necessary in view of this disclosure; however, if more information is needed, P. Hiemenz, Principles of See Colloid and Surface Chemistry (2nd Edition, 1986), pp. 513-529, which is incorporated herein by reference. [0065]

Now, with reference to FIGS. 2 and 2a, in another non-limiting embodiment of the method of modifying the surface area of a fiberglass carrier according to the present invention, the surface area of the fiberglass carrier 210 is such that the photoactive material 232 is the carrier 210. Prior to application, the coating 220 containing the high surface area silica material 222 can be increased by applying it to at least a portion 224 of the outer surface 226 of the carrier 210. For example, but not limited to, the carrier 210 carries a coating 220 of silica 222 (or other high surface area silica material) precipitated by spraying or dip coating the carrier 210 with an aqueous dispersion of silica. Can be treated by applying to a portion 224 of the surface 226 of. The photoactive material 232 can then be applied as described in detail below. As used herein, the term "high surface area silica material" means at least about 5 square meters per gram, preferably at least about 50 square meters per gram, as measured by BET surface area analysis using nitrogen. More preferably, it means a silica material having a surface area of at least about 100 square meters per gram, and most preferably at least about 250 square meters per gram. [0066]

Similarly, the coating 220 containing the high surface area silica material 222 can be applied to the portion 229 of the surface 218 of the fiber 214 and the strand 212 of the carrier 210 by a deposition process well known in the art. For example, but not limited to, high surface area silica material 222 can be added to the sizing composition and during formation by contacting the fibers 214 and strands 212 with a stationary or rotating applicator. And can be applied to strand 212 (as discussed above). [0067]

If not necessarily required, but desired, the silica material 222 may first be coated with a photoactive material prior to applying the silica material 222 to the carriers 210 and / or its fibers 214 and strands 212. Methods of coating the particles are well known to those of skill in the art, and given this disclosure, further discussion is not considered necessary. [0068]

In another non-limiting embodiment of the invention, the silicon-based metal-organic material or alkoxide is, for example, by spraying or dip-coating the carrier 210 with an aqueous or non-aqueous solution of the silicon-based metal-organic material or alkoxide. It may be applied to part 224 of surface 226 of carrier 210 and / or part 229 of surface 218 of fiber 214 and strand 212. The carrier 210 can then be thermally or chemically treated to condense the precursor material, and a high surface area silica coating 223 on the carrier 210 portion 224 and on the carrier 210 fiber 214 and strand 212 portion 229. Can form. The carrier 210 with the increased surface area coating can then be treated with the photoactive material 232 to form the photoactive matrix 230, as described in detail below. [0069]

In yet another non-limiting method of incorporating the high surface area silica material 222 in and / or also on the fibers 214 and strands 212 of the present invention, the precursor to the high surface area silica material 222 or the high surface area silica material 222 is a carrier. It can be applied there during the formation of 210. For example, but not limited to, an aqueous dispersion containing multiple chopped glass fibers 214 and strands 212, and a high surface area silica material 222 (or precursor to a high surface area silica material) can be formed, and then a sheet is formed. Can be cast. The sheet can then be at least partially dried to form fiberglass carriers 210, and if necessary, the carriers are processed to convert any precursor material to high surface area silica material 222 ( For example, by heating). The photoactive material 232 (and preferably the photocatalytic material) can then be applied to at least a portion of the surface 226 of the carrier 210 to form the photoactive matrix 230, and preferably the photocatalytic matrix 230. Alternatively, as discussed herein, the precursor for the photoactive material 232 or the photoactive material 232 is during carrier formation in addition to the precursor for the high surface area silica material 222 or the high surface area silica material 222. It can be incorporated into the carrier 210. [0070]

The amount of high surface area silica utilized can be any amount to achieve the desired surface area increase. It has been recognized by those skilled in the art that as the surface area of the high surface area silica material 222 used in the present invention increases, the amount of high surface area silica 222 required to achieve the desired surface area increase decreases. To. In one embodiment of the invention, the amount of high surface silica utilized is from about 1% by weight of the carrier glass fiber to more than about 100% by weight of the carrier glass fiber. And get in the range of. [0071]

Although not meant to be limited in the present disclosure, a coating comprising high surface area silica material 222 is applied on the fibers 214 and strands 212 and / or outer surface 226 of the fiberglass carrier 210 prior to treatment with the photoactive material 232. It is believed that by forming or forming more photoactive material 232 can be deposited on the carrier 210 as compared to carriers without such a high surface area coating. As discussed earlier, by providing a more available surface area to which the photoactive material can adhere, a larger amount of photoactive material can be incorporated into the carrier and of the photoactive matrix formed from it. It is believed that performance can be improved. [0072]

The application of photoactive materials to high surface area fiberglass carriers of the invention for forming photoactive matrices according to the invention is generally discussed here. Preferred photoactive materials include, but are not limited to, photocatalytic materials and photoelectrostatic materials in the present invention. [0073]

Suitable photocatalytic materials for use in the formation of photocatalytic matrices according to the present invention include, but are not limited to, photosensitive organic molecules, semiconductors and combinations thereof. Preferably, the photocatalyst material is a semiconductor photocatalyst, but not limited to the present invention. As used herein, the term "semiconductor photocatalyst" means a photocatalytic material formed from a semiconductor, and the term "semiconductor" means an element or compound having a valence band filled with 0K. However, it has a relatively low bandgap energy and has an electrical conductivity intermediate between the conductor and the insulator. Generally, the conductivity of semiconductors is about 10^-6(Ohm meters)^-1~ About 10⁴(Ohm meters)^-1The conductivity of the insulator is about 10^-10(Ohm meters)^-1~ About 10^-20(Ohm meters)^-1In the range of, the conductor is about 10⁷(Ohm meters)^-1It has an order of conductivity. W. Callister, Jr., Materials Science and Engineering An Introduction (2nd Edition, 1991), pp. 608 and 756; and G. Hawley, The Condensed Chemical Dictionary (10th Edition, 1981), pp. 914-915 (these are books). (Incorporated as a reference in the specification). [0074]

Suitable semiconductor photocatalysts, but not limited to the present invention, may have a crystal structure selected from the group consisting of diamond cubic, zinc blends, rock salts, wurtzite, and anatase. Examples of suitable semiconductor photocatalysts having a diamond cubic crystal structure include, but are not limited to, silicon and germanium. Examples of suitable semiconductor photocatalysts having a zinc blend structure include, but are not limited to, zinc sulfide, gallium arsenide, indium phosphide and gallium phosphide. Examples of suitable semiconductor photocatalysts with rock salt structures include, but are not limited to, lead sulfide, lead selenium, and tin telluride. Examples of suitable semiconductor photocatalysts having a wurtzite structure include, but are not limited to, zinc selenide, cadmium selenide and zinc oxide. A non-limiting example of a suitable semiconductor photocatalyst with an anatase structure is titanium dioxide. For more information on suitable semiconductor crystal structures, see N. Lewis et al., "Theory of Semiconductor Materials," Photocatalysis: Fundamentals. and Applications (supra), pp. 46-48, which is incorporated herein by reference. [0075]

Other non-limiting suitable photocatalysts include metal dicalcogenides and metal oxides. As used herein, the term "dicalcogenide" is commonly referred to as AB.₂Means a material with stoichiometry, where the metal layer (A) is between two chalcogenide layers (B), and the intermolecular binding between layers A and B is exclusively van der Waals. Depends on power. Examples of suitable metallic dicalcogenides include, but are not limited to, molybdenum disulfide, tungsten diserenede, and tungsten disulfide. Examples of suitable metal oxides include, but are not limited to, titanium dioxide, tungsten trioxide, iron oxide, and zinc oxide. [0076]

Non-limiting examples of photovoltaic materials suitable for use in the formation of photovoltaic matrices according to the present invention include silicon, gallium arsenide, and selenium. In order to take advantage of the photoelectrostatic properties of materials such as silicon, other materials (eg, conductors) may also be applied to the carriers of the invention in any combination with the photoelectrostatic material. Is understood by those skilled in the art. For example, but not limited to the present invention, a transparent conductive layer (eg, tin oxide or indium tin oxide) may be applied to the glass fibers of the carriers of the present invention prior to the application of the photovoltaic material. Similarly, an opaque conductive layer (eg, aluminum or copper) can first be applied to the glass fibers of the carriers of the invention, and the photoelectromotive material is applied on it by any means well known in the art. obtain. Alternatively, the photovoltaic material can be located between two conductive layers, at least one of which is applied directly to the fiberglass carrier to form a photovoltaic cell. Therefore, in addition to the photoactive material, the application of one or more other materials to fiberglass carriers is intended in the present invention. [0077]

Here, with reference to FIGS. 3 and 3a, there is extensive literature describing the application of photoactive materials on glass substrates, and the present invention presents photoactive materials 332 on the surfaces of fibers 314 and strands 312. It is not limited to any particular technique for making the photoactive matrix 330 by incorporating at least a portion 328 of the 318 and / or at least a portion 324 of the surface 326 of the carrier 310. However, it is free to use these photoactive materials 332, which can be applied from liquid media, to impregnate the high surface area fiberglass carriers 310. For example, without limiting the invention, the carrier 310 can be immersed in a liquid coating composition and a large surface area can be coated with the photoactive material 332. Without limiting the invention, metal oxide photocatalysts themselves serve the immersion coating process. This is because the metal alkoxide can be dissolved in a liquid solvent (usually alcohol) in which the carriers can be immersed. Subsequently (but not required), the deposited alkoxide can be hydrolyzed and condensed to form a metal oxide film that is well bonded to the glass substrate. A preferred non-limiting process of this type is U.S. Pat. No. 4,966, It is disclosed in No. 759, which is incorporated herein by reference. More specifically, the patented process requires a metal alkoxide as a starting material, which can be, in the preferred case of a titanium dioxide photocatalyst, for example titanium ethoxyoxide. Titanium ethoxydo is dissolved in an organic solvent (eg, absolute ethanol) and reacts with a controlled amount of acid (eg, nitric acid) and water to form a coating solution. Fiberglass carriers can be immersed in the coating solution for approximately one minute under dry conditions. Subsequently, the coated carriers are hydrolyzed by drying them in air at room temperature, thereby forming an amorphous polymer titanium layer on the carriers. After the coating has dried for 1-2 hours, the coated mat is heated to a temperature sufficient to convert the amorphous layer into a photocatalytically active crystalline form (anatase in the case of titanium dioxide). .. The heating cycle for producing anatase titanium dioxide can include a slow heating period on the order of about 2-5 hours, a retention at about 400 ° C. for 1 hour, and a cooling period on the order of about 5 hours or more. It is understood that coating and heat treatment conditions will vary depending on the particular material used, as known to those of skill in the art. [0078]

It is also known to apply photocatalytic metal oxides onto substrates using aqueous media. For example, titanated products (particularly chelated versions) available from EIduPont de Nemours and Company (Wilmington, Delaware) under the trade name TYZOR, or Degussa Corporation (especially chelated versions), but not limited herein. An aqueous solution or slurry of a similar product from Germany) can be used to coat the carriers of the invention. [0079]

A further advantage that may be attributed to the presence of the coupling agent in the preferred non-limiting embodiment of the present invention is that an improved coating of the moist photoactive material on the fiberglass carrier is achieved. .. Thermal cleaning of carriers In conventional practice, this advantage is lost due to the presence of thermal decomposition of any coupling agent. [0080] [0080]

It is also known to dope a photoactive material (particularly a photocatalytic material) with another metal (eg platinum) to enhance the photocatalytic activity of the catalyst, and the photocatalytic matrix of the present invention is such a dopant. May include. However, in one non-limiting embodiment of the invention, the photocatalytic matrix formed from the fiberglass mat carrier according to the invention is selected from the group consisting of oxides of copper, iron, molybdenum, vanadium, and tungsten. It is basically free of the second catalytically active factor. [0081]

The photoactive material is obtained by applying the photoactive material to the surface of a fiberglass carrier (eg, by treating the carrier with a photoactive material after the carrier has been formed (as discussed above)). Although it can be incorporated into the carrier, in one preferred non-limiting embodiment of the invention, the photoactive material is incorporated into the carrier during the formation of the carrier. For example, but not limited to, the powder form of the photoactive material can be dispersed in an aqueous solution with glass fibers and a foaming agent, after which the dispersion is agitated to form a foamed slurry. The foamed slurry can then be cast to form a sheet. At least a portion of the foam can then be removed, and the sheet can be at least partially dried to form a photoactive matrix in the form of fiberglass carriers with the photoactive material dispersed therein. If desired, an additional coating containing a photoactive material may be applied to the carrier after formation according to the invention. Although not meant to limit the invention, the powder form of the photoactive material is Radlite.^TMBy adding to the foamed slurry of the process (described in detail above), a relatively large amount of photoactive material is used when compared to adding a powdered photocatalyst to a conventional wet-laid paper manufacturing process. It can be more evenly dispersed through the carriers formed from it. The foamed slurry used can help reduce or limit the solidification of the photoactive material and can allow enhanced mixing between the powdered photoactive material, the glass fibers, and the glass strands. In addition, as discussed earlier, Radlite^TMThe process can produce high surface area carriers due to the large amount of filamentation that occurs during agitation and foaming. [0082]

In certain non-limiting examples of methods for forming photocatalytic matrices according to the present invention (where the photocatalytic material is titanium dioxide), one or more water-soluble titanium complexes (eg, disclosed in US Pat. No. 5,908,497). Is solubilized in an aqueous solution or white aqueous solution containing one or more foaming agents before dispersing the glass fibers. The sheet is then cast from the dispersion and dried to form carriers. After drying, the carriers are exposed to high temperatures for a time sufficient to condense and crystallize the titanium complex, forming a photocatalytically active form of titanium dioxide. Without limiting the invention, preferably, the titanium complex is converted to the anatase form of titanium dioxide. Those skilled in the art will appreciate that the exact temperature and time required to form the anatase phase of titanium dioxide will, in part, depend on the type of titanium complex used. By no means limiting this disclosure, for example, temperatures in the range of about 300 ° C to about 500 ° C may be used to convert the water-soluble titanium complexes detailed in US Pat. No. 5,908,497. .. The above method of adding a photocatalyst is a conventional wet raid process or the Radlite discussed above.^TMIt will be further understood by those skilled in the art that it can be used in any of the processes. [0083]

In another particular non-limiting example of applying the photocatalytic material to the fiberglass carriers formed via the wet raid process discussed above, the water-soluble titanium complex is solubilized in an acidic white aqueous solution. .. The chop fiberglass strands are then dispersed in this solution to form a suspension, which is subsequently cast and dried to form carriers. The carrier is then treated with an alkaline solution (eg, by immersing the sheet in an alkaline bath having a pH of at least about 3.5) to condense the titanium complex. Since titanium dioxide has an isoelectric point at pH 3.5, the titanium complex can be condensed by such an alkali treatment to form titanium dioxide. The isoelectric point of other photocatalysts can be different from the isoelectric point of titanium dioxide, and it is by those skilled in the art that the pH of the alkaline solution should be selected according to the isoelectric point of the particular photocatalytic material used. Understood. Condensation of the photocatalyst using alkaline treatment, although not meant to be constrained by any particular theory, can improve the integrity of the fiberglass carriers, as opposed to heat treatment. This is because high temperature treatment can make the glass fibers brittle and can damage them, making the carriers more fragile. [0084]

In another non-limiting embodiment of the invention in which the fiberglass carriers are formed using an air-laid process, the photoactive material needs the carriers, as discussed above. Before, during or after, it can be sprayed or deposited on the carrier (eg, by chemical vapor deposition or plasma spray). [0085]

It is further recognized by those skilled in the art that the photoactive material can be applied directly to the fiberglass strands during or in addition to applying the photoactive material during or after carrier formation. .. For example, but not limited to the present invention, the photocatalytic material or precursor of the photocatalytic material can be added directly to the sizing composition applied to the glass fiber shortly after formation. The fibers can then be assembled together to form a strand, which is further processed into a fiberglass carrier as discussed above. Additional photocatalytic material can be added to the carriers during carrier formation (eg, as discussed above) Radlite.^TM(By adding a photocatalyst to the foam slurry used in the process) and / or can be applied to the carrier after formation. [0086]

Similarly, the surface of the fiber can be treated during the fiber forming process, either by etching or by applying a high surface area silica coating, and then processed into a carrier and / or photoactive matrix as discussed above. To. [0087]

Here, embodiments of the present invention are set forth in certain non-limiting examples below. [0088]

(Example) Fiberglass carriers with high surface area were formed using the air raid mat process according to the following procedure. Multiple E-glass fiber strands containing filaments with an average diameter of about 9 micrometers (referred to as "G" fibers) were treated with the sizing composition given in Table 2 during formation. The fiber strands were then woven to form a package, which was subsequently dried at about 245 ° F (about 118 ° C) for about 12 hours. [0089]

[Table 2]

<img file="JP2003519002A_D0002.tif" /> After drying, the package was rewoven from the inside, and fiber strands were continuously fed to a chopping device, which chopped them to a length of about 2 inches (about 5 centimeters). After chopping, the strands are immediately threaded through the RANDO-OPENER BLENDER, which is part of the MODEL B RANDO-WEB® processor (commercially available from Rando Machine Corporation (Macedon, New York)). These were opened or filamentized (as discussed in detail above). Then open the strands, RANDO-WEBBER® (which is also MODEL B). RANDO-which is part of the WEB® processor) and formed into a continuous web. The web is then passed through a needling device, and with a needleboard reciprocating speed of about 359 strokes per minute and a perforation depth of about 0.55 inches (about 1.4 centimeters), about 150 perforations per square inch (1). Needling to form a mat with a perforation density of approximately 23 perforations per square centimeter). The needle used in the needling device was a 32-gauge star-shaped needle (described in detail above), which is commercially available from Groz-Beckert USA (Charlotte, North Carolina). The average surface weight (or mat density) of this mat was about 0.7 ounces per square foot (about 214 grams per square meter). [0090]

After formation, three square samples weighing about 20 to about 24 grams were cut from the mat. Each of the samples was then separately immersed in about 3-4 liters of 2N hydrochloric acid (commercially available from Fisher Scientific of Pittsburgh, Pennsylvania) and the acid was heated to a temperature of about 90 ° C to about 95 ° C. Upon reaching the desired temperature, the samples were soaked in acid for the time shown in Table 2 below to etch the glass fibers. After etching, heating was stopped and the acid was cooled to room temperature before removing the sample. After removing the sample from the acid, the sample was rinsed with deionized water and dried. [0091]

BET surface area analysis was then performed on each of the three samples and unetched controls at liquid nitrogen temperature using a Micromeritics ASAP2400 nitrogen porosity meter. Prior to the measurement, the sample was dried in a porosity meter under vacuum at about 165 ° C for about 1 hour or until the vacuum level was below about 200 milittles. The results are shown in Table 3. [0092]

[Table 3]

<img file="JP2003519002A_D0003.tif" /> The surface area of the unetched control was significantly smaller than that of the etched sample, indicating that the etching procedure was successful in increasing the surface area of the glass fiber. [0093]

To provide the best embodiments of the invention, the invention has been described with specific embodiments. It should be understood that other modifications and modifications known to those of skill in the art can be used within the scope of the invention as defined by the claims.

[Simple explanation of drawings]

[Figure 1]

1 and 1a are schematic cross-sectional views of a fiberglass carrier incorporating the features of the present invention. [Figure 2]

2 and 2a are schematic cross-sectional views of another embodiment of a fiberglass carrier incorporating the features of the present invention. [Fig. 3]

3 and 3a are schematic cross-sectional views of a photoactive matrix incorporating the features of the present invention.