JP4890106B2 - Production method of functional filter materials - Google Patents

Description

The present invention is high and breathability durability relates to a process for the preparation of good der Ru filter material during high temperature service.

  In addition to solid components such as dust, hydrogen chloride, nitrogen oxides, sulfur oxides, and carbon monoxide, exhaust gases released into the air from municipal waste incinerators and boilers contain a variety of harmful substances such as dioxins. It is included in large quantities. Since the emission standards for exhaust gas have been tightened year by year to prevent pollution, incinerator manufacturers have improved the structure and functions of the furnace so that advanced exhaust gas treatment can be performed. There is a strong demand for improving the performance of the bug filter itself.

  As a filter material of this type, in Japanese Patent Application Laid-Open No. 8-196830, a PTFE (polytetrafluoroethylene) base fabric is disposed at the center of the staple fiber felt layer, and both sides of the base fabric or two base fabrics. A fine cloth such as a catalyst is mixed in between, and then needle punching is performed to form a filter cloth. In Japanese Patent Laid-Open No. 10-230119, catalyst powder is attached to the fiber of a filter cloth, and a porous thin film of PTFE is bonded to one side of the filter cloth. In JP-A-11-244636, a base cloth is impregnated with an active fine particle slurry such as a catalyst and dried, and then a web-like filter material is supplied to both sides of the base cloth and then the whole is pressure-bonded. In JP-A-2005-7394, catalyst powder is mixed with a powdery adhesive, and the mixed powder is spread on a felt sheet, and then another felt sheet is laminated and the whole is heat-treated. Needle punching is performed.

The filter material disclosed in Japanese Patent Application Laid-Open No. Hei 8-196830 holds a fine cloth mixed with fine powder such as a catalyst inside the felt layer and carries the fine powder on the outer felt layer, so that the fine powder falls off. It is kept for a long time without any harmful substances in the exhaust gas. The filter material disclosed in Japanese Patent Application Laid-Open No. 10-230119 prevents the catalyst powder from falling off during backwashing and prevents the catalyst from being contaminated by dust or the like by a porous thin film adhered to the surface of the filter cloth. The filter material disclosed in Japanese Patent Application Laid-Open No. 11-244636 can maintain the activity for a long period of time without the active fine particles falling off from the surface of the filter material by holding the base fabric carrying the active fine particles by the filter materials on both sides. In addition, the filter material disclosed in Japanese Patent Application Laid-Open No. 2005-7394 is fixed to the catalyst powder by melting the adhesive, and the adhesive is denatured by the heat of the exhaust gas during use. The catalyst powder is hardly dropped off during production and use after heat treatment, and harmful substances contained in the exhaust gas can be removed over a long period of time.
JP-A-8-196830 Japanese Patent Laid-Open No. 10-230119 Japanese Patent Laid-Open No. 11-244636 JP 2005-7394 A

  The filter material disclosed in Japanese Patent Application Laid-Open No. Hei 8-196830 only carries fine powder such as a catalyst on the outer felt layer, so that the fine powder is scattered during needle punch processing or pulse jet during backwashing. It is difficult to use the fine powder for a long period of time because the fine powder easily falls off the felt layer. In the filter materials disclosed in JP-A-10-230119 and JP-A-11-244636, the catalyst is retained by a so-called impregnation method in which the base fabric is dipped in a catalyst slurry and then dried. It is not sufficient, and the catalyst is likely to fall off the filter material due to pulse jet, etc., it cannot be used for a long time, the life of the filter material is short, and the dropped catalyst may flow out of the system and cause pollution problems. .

  On the other hand, in the filter material disclosed in Japanese Patent Application Laid-Open No. 2005-7394, since the mixed powder containing the catalyst is sandwiched between the felt sheets and fixed to the sheet with an adhesive, the catalyst powder is dropped off during the manufacturing and use stages. On the other hand, since the catalyst powder is spread on the sheet from the mixer, the thickness of the catalyst layer between the sheets tends to be non-uniform, which may be insufficient in terms of reliably removing harmful substances. Furthermore, although the powdery adhesive coexisting with the catalyst powder is melted at the time of manufacture but is present until the filter material is used, when the adhesive is PVA (polyvinyl alcohol), it is at a high temperature of 150 to 250 ° C. When the exhaust gas treatment is performed, the PVA and the catalyst may chemically react to dissolve the PTFE felt sheet, and the filter material may become unusable in a short period of time. Since this filter material is thermocompression bonded to support the catalyst, the air permeability is lowered, and when high-temperature exhaust gas passes, unevenness occurs and the temperature becomes locally high, which may cause PVA to react. It gets even higher.

  The present invention has been proposed in order to improve the above-mentioned problems associated with conventional filter materials, and by dispersing fine particles of functional substances in a liquid binder and fixing them, the functionality can be improved during manufacture and use. It is an object of the present invention to provide a method for producing a functional filter material in which the fine powder of the substance hardly falls off and the thickness of the functional substance layer is uniform. Another object of the present invention is to provide a method for producing a functional filter material that can be used for a long period of time by removing the binder by heat treatment before use. Another object of the present invention is to provide a method for producing a functional filter material that does not cause a decrease in air permeability and does not cause unevenness in the passage of high-temperature exhaust gas, because thermocompression bonding for supporting a functional substance is not performed. Is to provide.

  The production method according to the present invention is a method for producing a functional filter material in which the thickness of the functional substance is uniformly formed on the entire surface. In the production method according to the present invention, the fine powder of the functional substance is dispersed in a liquid binder, and the dispersion is adhered to the felt sheet to uniformly fix the fine powder on the sheet surface, and then the binder is removed by high-temperature heat treatment. Remove by pyrolysis or vaporization. Further, the other felt sheet is polymerized on the fixing surface of the fine powder of the functional substance, and the whole is integrated by a needle punch. Further, after the fine powder of the functional substance is fixed to the sheet surface, the other felt sheet is polymerized on the fixed surface of the fine powder of the functional substance, and the whole is integrated by the needle punch. The binder may be removed by thermal decomposition or vaporization by heat treatment.

  In the production method according to the present invention, the two felt sheets are preferably prepared by pre-punching card wraps of heat-resistant fibers, and both the felt sheets are preferably heat-treated at 200 to 250 ° C. before polymerization of both. Preferably, the liquid binder is PVA dissolved in warm water. Water is added to the fine powder of the functional substance and stirred to disperse, and then a predetermined amount of the liquid binder is added while stirring the dispersion.

  In the production method according to the present invention, it is preferable that one or both of the two felt sheets are integrated by interposing a base fabric of heat-resistant fibers, and the base fabric is disposed on the inner surface or the middle of the felt sheet. Moreover, after integrating the whole by needle punching, it is possible to further laminate a porous film of a fluororesin or coat a fluororesin. Furthermore, the dispersion binder liquid containing the fine powder of the functional substance is adhered to either of the surfaces of the two felt sheets to fix the fine powder, and then the fixing surfaces of both fine powders are joined and integrated. Is also possible.

  The present invention will be described with reference to the drawings. FIG. 1 illustrates a functional filter material 1 manufactured by the method of the present invention, and the filter material typically includes a functional material layer 5 between felt sheets 2 and 3. It has a sandwiched structure. The fine powder of the functional substance may be dispersed in a liquid binder, and the dispersed binder liquid 6 may be adhered to the felt sheet 2 or 3 to uniformly adhere the fine powder to the sheet surface as shown in FIG. A felt sheet on which the functional material layer 5 is laminated is obtained by passing through a heating furnace 7 and drying.

Felt Sheet 2 is a fiber sheet used in the present invention, Ru also der be used preferably when produced by Purepanchi the web or card wrap of the heat-resistant fibers, normal web or non-woven fabric. Examples of the fiber sheet include needle punch, spun bond, spun lace, melt blown, stitch bond, and wet felt when classified from the manufacturing process. For example, the pre-punch may be punched downward or vertically with a needle number of 30 to ²⁰⁰ / cm ² and a depth of 10 to 17 mm. The basis weight of each felt sheet is generally 200 to 500 g / m ² .

  Examples of heat resistant fibers used in the felt sheets 2 and 3 include PTFE fibers, polyamide fibers, polyimide fibers, polyamideimide fibers, polyester fibers, polypropylene fibers, ceramic fibers, and glass fibers. This heat-resistant fiber preferably has a melting point of around 250 ° C. so as not to melt during high-temperature heat treatment. Suitable organic fibers of this type include PTFE fiber (melting point 327 ° C.), polyester fiber (melting point 255-260 ° C.), polyphenylene sulfide (PPS) fiber (melting point 287 ° C.), polyether ether ketone fiber, 66 nylon fiber (melting point). 250-260 ° C.) and heterocyclic fibers, and these fibers and other high heat resistant fibers and non-melting fibers may be used in the form of composite fibers or mixed fibers.

  It is desirable that the felt sheets 2 and 3 have smaller holes by pre-punching with respect to the particle size of the functional substance such as a catalyst. The opening of the felt sheets 2 and 3 is, for example, 30 to 80 μm so as not to prevent the passage of exhaust gas. When the base fabric 8 (FIG. 2) is interposed, the opening of the felt sheets 2 and 3 is appropriately set. Adjust it. With such an opening, it is possible to more reliably prevent the functional substance powder from falling off when hitting during backwashing.

The two felt sheets 2 and 3 may have a heat-resistant fiber base fabric 8 interposed in one or both of them as desired, and the base fabric is preferably integrated with the sheet by pre-punching. The base fabric 8 is heat resistant like the felt sheets 2 and 3 and may be a woven fabric, a knitted fabric, a nonwoven fabric, a mesh fabric, or the like, and its basis weight is usually 80 to 150 g / m ² . The integration of the felt sheets 2 and 3 and the base fabric 8 may be performed separately by sewing or an adhesive in addition to the pre-punching process. In general, the base fabric 8 is preferably interposed on one side of the functional material layer 5 in the felt sheets 2 and 3.

The functional material in the form of fine powder used in the present invention is a catalyst that decomposes harmful substances such as dioxins in exhaust gas, activated carbon or activated coke that adsorbs hydrogen chloride, sulfur oxide, etc., depending on the application. The catalyst usually used is composed of at least one of metal oxides such as titanium, silicon, copper, iron, manganese, silver, chromium, aluminum, zirconium, gold, platinum, molybdenum, vanadium, tungsten, and cobalt. That's fine. In particular, when metal oxides such as titanium, silicon, aluminum, and zirconium are the main components, and metal oxides such as vanadium, tungsten, silver, chromium, molybdenum, gold, platinum, cobalt, copper, and iron are supported. preferable. As an example, the catalyst consists of titanium dioxide (TiO ₂ ) and vanadium pentoxide (V ₂ O ₅ ), which are oxides of titanium and vanadium.

  Metal oxide catalysts have high resolution against dioxins, which are harmful substances in exhaust gas, and can decompose and modify organic compounds other than organic halogen compounds, sulfur oxides, nitrogen oxides, carbon monoxide, etc. is there. For example, the honeycomb-shaped lump may be jet-pulverized so that the catalyst has a particle size larger than the pores of the felt sheets 2 and 3, and the average particle size is preferably 100 to 300 μm.

In addition to the above metal oxide catalyst, the functional material may contain a trace amount of sulfur or a compound thereof, phosphorus or a compound thereof, etc., and when these materials are added to the metal oxide catalyst, the functional material decomposes into dioxins. The effect can be further improved. The content of the catalyst may be set within a range in which harmful substances contained in the exhaust gas can be efficiently removed and a predetermined gas passage amount can be secured. For example, the content of the catalyst is preferably 50 to 1000 g / m ² .

  On the other hand, the liquid binder used in the present invention requires that the fine powder of the functional substance can be reliably fixed to the sheet surface and can be substantially removed by thermal decomposition, vaporization, dissolution, shrinkage, etc. by high-temperature heat treatment. The liquid binder that can be substantially removed by high-temperature heat treatment is, for example, a PVA solution dissolved in a solvent such as water, and in addition, a thermoplastic resin solution having a relatively low melting point can be used. When the liquid binder is a PVA solution, water is added to the fine powder of the functional substance and stirred to uniformly disperse, and then a predetermined amount of the liquid binder may be added while stirring this dispersion.

  The binder liquid 6 in which the fine powder of the functional substance is dispersed is adhered to the felt sheets 2 and / or 3 to uniformly adhere the fine powder to the sheet surface and then dried. The liquid binder may be applied by roll coating using the roller 10 as illustrated in FIG. 5 or may be attached to the sheet surface using a screen printing method, an impregnation method, a roller impregnation method, a spray method, or the like. Good. The liquid binder fixed to the sheet surface is preferably dried before high-temperature heat treatment to remove the binder, and the fine powder of the functional substance is preferably fixed to the sheet surface.

  The liquid binder adhered to the sheet surface is removed from the sheet surface by thermal decomposition or vaporization by high-temperature heat treatment after drying, exposing the surface of the functional material covered by the binder, and in the stage of treating exhaust gas, It is possible to increase the frequency of contact with functional substances and efficiently remove harmful substances. This liquid binder securely adheres the functional substance to the felt sheet 2, prevents the functional substance from falling off by a pulse jet during backwashing, and is usually heat treated at 200 to 250 ° C. By removing the action that covers the surface of the substance and hinders its function, the function of removing harmful substances by the functional substance is effectively exhibited. About the liquid binder to be used, the heat processing temperature and processing time can be adjusted by increasing / decreasing the kind or its density | concentration, and the addition amount of a functional substance.

The amount of the liquid binder may be set in a range that is sufficient to fix the functional substance and can be substantially removed by high-temperature heat treatment. The amount of the liquid binder may be 70 to 200% with respect to the functional substance. In the case of PVA, the PVA powder is preferably about 70 to 140 g / m ² and the water is about 150 to 400 g / m ^2. .

  As shown in FIG. 3, the functional filter material may be thermocompression bonded with a fluororesin porous film 12 superimposed on one or both sides thereof. In FIG. 3, the porous film 12 is thermocompression bonded to the felt sheet 3, and the porous film can be thermocompression bonded to the felt sheet 2. Alternatively, the felt sheets 2 and 3 may be impregnated with a fluororesin dispersion or the like, and the porous film 12 may be superposed and thermocompression bonded. The functional filter material 14 shown in FIG. 3 has both the original characteristics of the felt and the characteristics of the porous film 12, has a high dust collection performance, and has high non-adhesiveness and low friction resistance derived from the porous film 12. , Breathability, water repellency and the like.

  The fluororesin that is a material of the porous membrane 12 is preferably a PTFE resin having a thickness of 10 to 100 μm that has excellent heat resistance, chemical resistance, and non-adhesiveness. The PTFE resin becomes a flexible and tough porous film when the fine powder is subjected to paste extrusion and then stretched and heat-treated. In the field in which mechanical properties and electrical properties are mainly used as the porous membrane 12, tetrafluoroethylene-perfluoroalkyl vinyl ether copolymer (PFA), tetrafluoroethylene-hexafluoropropylene copolymer (FEP), poly Also used are chlorotrifluoroethylene (PCTFE), tetrafluoroethylene-ethylene copolymer (ETFE), chlorotrifluoroethylene-ethylene copolymer (ECTFE), polyvinylidene fluoride (PVDF), polyvinyl fluoride (PVF), etc. Is possible. Since the PTFE porous membrane has sufficient collection performance, there is no need to particularly limit the pore diameter, porosity, thickness, and the like.

In the functional filter material of the present invention, a fluorine-based resin can be coated on one side or both sides. This coating improves the releasability of the dust. The resin to be used is not limited, but PTFE or FEP dispersion is preferable. The coating method is not particularly limited, and a roll coating method, a reverse coating method, or the like is preferably used. The coating amount is 10 to 100 g / m ² , preferably 30 to 60 g / m ² . If it exceeds 100 g / m ² , the decrease in air permeability becomes large, and if it is less than 10 g / m ² , the release effect is small, which is not preferable.

The thickness of the functional filter material 1 is 1 to 10 mm as a whole, and the total basis weight is preferably 500 to 2000 g / m ² . When the thickness is 1 to 10 mm, a predetermined gas flow rate can be secured, and pressure loss is reduced when the filter material is used for a bag filter. Further, if the total basis weight is less than 500 g / m ² , sufficient rigidity cannot be obtained, and if it exceeds 2000 g / m ² , the air permeability decreases, which is not preferable.

  The functional filter material 1 manufactured by the method of the present invention may have a base fabric 8 interposed on one side of the felt sheet 3 as shown in FIG. 2 in addition to the structure shown in FIG. In this case, the filter material 16 is disposed so that the felt sheet 3, the base cloth 8, the functional substance layer 5, and the felt sheet 2 are laminated in this order toward the upstream in the exhaust gas flow direction. By disposing the felt sheet 3 toward the uppermost stream in the flow direction of the exhaust gas, it is possible to prevent the dust contained in the exhaust gas from entering the inside of the filter with the base cloth 8, and it is possible to avoid rapid contamination of the catalyst by the dust. Further, as shown in FIG. 3, in the filter material 14 in which the porous membrane 12 is laminated, a large amount of dust contained in the exhaust gas is made porous by disposing the porous membrane 12 toward the uppermost stream in the exhaust gas flow direction. Adhering to the material film 12 can prevent the felt sheets 2 and 3 and the catalyst from being rapidly fouled by dust. The laminated structure of the functional filter material is not limited to FIGS. 1 to 3, and for example, a base fabric can be interposed in the felt sheet 2.

The manufacturing method of the functional filter material 1 is clear from FIGS. 5 and 6. In FIG. 5, the binder liquid 6 in which fine powder of the functional substance is dispersed is accommodated in the tank 18, attached to one side of the felt sheet 3 through the roller 10, and then passed through the heating furnace 7 and sufficiently dried. . The dispersion binder liquid 6 is adhered by 500 to 1000 g / m ² by the roller 10, and when the adhesion amount is insufficient, it may be adhered twice by the roller. When the adhered binder liquid 6 passes through a heating furnace 7 heated to about 140 ° C., the water evaporates and solidifies, and the fine powder of the functional substance can be fixed to the felt sheet 3 by the binder component, and the functional substance layer 5 is formed. The laminated felt sheet 3 can be wound around the roll 20.

  In FIG. 6, both the felt sheet 2 and the laminated felt sheet 3 are passed through the high-temperature heating furnace 22 and heat-treated at a high temperature of 200 to 250 ° C., and then both the felt sheets 2 and 2 are polymerized and further subjected to needle punching. The laminated felt sheet 3 is heat-treated at 200 to 250 ° C. in the heating furnace 22, whereby the binder content in the functional material layer 5 is thermally decomposed or vaporized and removed from the functional material layer 5. Since the fibers constituting the felt sheets 2 and 3 are softened by a high-temperature heat treatment, it is not necessary to sufficiently entangle the needle sheets 24 from the up and down direction and to perform a crimping process.

  In the above, the binder liquid in which the functional substance is dispersed is applied to the felt sheet and dried, and the binder component is vaporized and removed by high-temperature heat treatment, and then integrated with another felt sheet by a needle punch. . In this case, it is also possible to remove the binder component by high-temperature heat treatment after applying and drying the binder and previously integrating the felt sheet and the needle punch.

  By the production method according to the present invention, fine powders of functional materials such as catalysts and adsorbents are dispersed in a liquid binder and adhered to a felt sheet, and the thickness of the functional material layer is uniform compared to the powder spraying. In addition, since there is no unevenness when high-temperature exhaust gas passes, harmful substances can be removed reliably. In the functional filter material manufactured by the method of the present invention, the functional substance is fixed to the felt sheet by the binder and is further sandwiched between the felt sheets, so that the fine particles of the functional substance may drop off during manufacture and use. Absent. In this functional filter material, the fine powder of the functional substance does not fall off during use, and the functional substance can be retained for a long period of time, so that harmful substances in the exhaust gas can be efficiently removed.

  In the functional filter material produced by the method of the present invention, the binder such as PVA is removed by heat treatment before use, and when the exhaust gas treatment is performed at a high temperature of 150 to 250 ° C., the remaining PVA becomes a catalyst or the like. It can be used for a long period of time without chemically reacting with the functional substance to dissolve the PTFE felt sheet. Since this functional filter material does not perform thermocompression bonding to support a functional substance, the air permeability is less likely to deteriorate during use, and the passage of high-temperature exhaust gas is uniform over the entire surface, resulting in harmfulness in the exhaust gas. The substance can be removed more reliably.

  Next, the present invention will be described based on examples, but the present invention is not limited to the examples. In FIG. 2, the functional filter material 16 is illustrated, and the felt sheets 2 and 3 constituting the filter material are both produced by pre-punching a card wrap of PTFE fiber.

The felt sheet 2 is needle punched from above in a pre-punch using a 36th needle under the condition of a needle depth of 13 mm, and the basis weight is 420 g / m ² . On the other hand, the felt sheet 3, in Purepanchi, needle density forty / cm ² using a 36 fastest needle, and needle-punched from above under the condition of the needle depth 15 mm, overlapping the base fabric 8 of PTFE fabric Further, using a 36th needle, the base fabric 8 is integrated by needle punching from above and below under the conditions of a needle density of 150 / cm ² and a needle depth of 13 mm. The basis weight of the obtained felt sheet 3 is 420 g / m ² , and the basis weight of the base fabric 8 is 120 g / m ² .

The functional substance is dispersed in the liquid binder according to FIG. This functional substance is a powder of a metal oxide catalyst, and is composed of titanium dioxide (TiO ₂ ) and vanadium pentoxide (V ₂ O ₅ ), which are oxides of titanium and vanadium. The liquid binder is, for example, a PVA solution dissolved in a solvent such as water. In S1 of FIG. 4, while stirring hot water at 70 to 80 ° C., PVA powder (Product No .: JMR-10MDV, manufactured by Nihon Vinegar & Poval) is gradually added, and the total amount of 110 g is sufficiently stirred so as not to cause lumps. . The obtained PVA solution is allowed to cool to room temperature by allowing it to stand for 1 to 2 days in S2.

  On the other hand, the metal oxide catalyst which is the functional substance 5 is passed through a 40-mesh sieve in S3 to obtain a fine powder, 330 g is weighed in S4, and 250 g of water is further added in S5 and stirred well. While continuing this stirring, a predetermined amount of the above PVA solution is added in S6, and stirring is performed until there is no lumps. The compounding ratio of the PVA solution 6 (FIG. 5) in which the fine powder of the metal oxide catalyst is dispersed is 330 g of catalyst, 110 g of PVA, and 360 g of water, and the concentration of the catalyst and PVA is 55%.

In FIG. 5, while the felt sheet 3 is run horizontally, the dispersed PVA solution 6 is accommodated in a tank 18, attached to one side of the felt sheet 3 on the base cloth side by a roller 10, and then heated to 140 ° C. The felt sheet 3 on which the catalyst layer 5 is laminated is wound around a roll 20. When the dispersed PVA solution 6 in which the fine powder of the catalyst is dispersed passes through the drying furnace 7 heated to about 140 ° C., the water evaporates and solidifies to fix the catalyst to the felt sheet 3. The catalyst layer is made of a catalyst 330 g / ^{m 2} and PVA110g / ^{m 2.}

  The felt sheet 2 and the laminated felt sheet 3 are both heat-treated at a high temperature of 200 to 250 ° C. through a high-temperature heating furnace 22 in FIG. The laminated felt sheet 3 is heat-treated at 200 to 250 ° C. in the heating furnace 22 with the catalyst layer 5 facing upward, whereby PVA in the catalyst layer 5 is thermally decomposed or vaporized and removed from the catalyst layer. From this high temperature heat treatment to the next punching 24, it may be wound once on a roll as shown in the figure, or may be continuously processed. By this high-temperature heat treatment, the fibers constituting the felt sheets 2 and 3 are softened by the high-temperature heat treatment, so that it is not necessary to be sufficiently entangled by the needle punching process 24 from the vertical direction and further subjected to the crimping process. is there.

In the punching process 24, a 40th conical needle is used to perform needle punching in the vertical direction under the conditions of a needle density of 100 needles / cm ² and a needle depth of 17 mm to integrate the whole. In the obtained filter material 16, the weight of the felt sheets 2 and 3 was 420 g / m ² , the weight of the base fabric 8 was 120 g / m ² , and the catalyst was 330 g / m ² . In the punching process 24, needle clogging does not occur, and the felt sheets 2 and 3 in the filter material 16 do not peel off.

  In the functional filter material 16, since the thickness of the catalyst layer 5 is uniform and unevenness cannot occur when high-temperature exhaust gas passes, harmful substances can be reliably removed. Since the catalyst in the catalyst layer 5 is fixed to the felt sheet 3 by the binder and is further sandwiched between the felt sheets 2 and 3, the catalyst can be maintained for a long period of time without dropping of the catalyst fine particles during production and use. Since the functional filter material 16 removes PVA by high-temperature heat treatment before use, when the exhaust gas treatment is performed at a high temperature of 150 to 250 ° C., the remaining PVA chemically reacts with the catalyst to produce PTFE felt. The sheet can be used for a long time without melting. Since the functional filter material 16 does not perform thermocompression bonding, the air permeability is less likely to deteriorate during use, and harmful substances in the exhaust gas can be reliably removed.

  Processing is performed in the same manner as in Example 1 to produce a functional felt material. A PTFE porous membrane 12 (trade name: Poeflon, manufactured by Sumitomo Electric Fine Polymer Co., Ltd.) having a pore diameter of 15 μm and a thickness of 25 μm is superimposed on the surface of this felt material, and passed through a roll laminator (not shown) at a temperature of 220 ° C. and a linear pressure of 0 The porous film 12 was thermally bonded under the conditions of 0.08 MPa · cm and a speed of 1 m / min.

The obtained functional felt material 14 (FIG. 3) has good adhesion between the felt sheet 3 and the porous membrane 12, and its air permeability is ² cc / cm ² seconds. The air permeability of the functional felt material 14 was measured by a Frazier type air permeability tester. The functional felt material 14 has a very high dust collection performance, and is suitable for various filter applications including an exhaust gas bag filter having a high degree of contamination and a large amount of dust adhesion.

It is an expanded sectional view showing the functional filter material concerning the present invention. It is an expanded sectional view which shows the modification of a functional filter material. It is an expanded sectional view showing another modification of a functional filter material. It is a flowchart which illustrates the manufacturing process of the dispersion | distribution binder liquid used by this invention. It is a schematic side view which shows the adhesion | attachment and drying process of the dispersion | distribution binder liquid to a felt sheet. It is a schematic side view which shows the process of manufacturing a functional filter material from two felt sheets.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Functional filter material 2,3 Felt sheet 5 Functional material layer 6 Dispersion binder liquid 8 Base cloth 12 Porous membrane

Claims (8)

A method for producing a filter material in which the thickness of a layer containing at least a metal oxide is uniformly formed on the entire surface, wherein a fine powder of a metal oxide is dispersed in a liquid binder, and the dispersed binder liquid is applied to a fiber sheet. the fine powder is dried after application of uniformly affixed to the sheet surface, removal and binder were thermally decomposed or vaporized by the heat treatment, the further fixing surface of the fine powder of metal oxides, other fiber sheet was heat-treated the superposition method for producing a filter material Ru is integrated across the needle punching in a state in which both fiber sheet fiber in the heat treatment is softening. A method for producing a filter material in which at least the thickness of a layer containing a metal oxide is uniformly formed on the entire surface, wherein a fiber sheet, which is a felt sheet having an aperture of 30 to 80 μm, is prepared by pretreating a web with a needle punch used, a fine powder of metal oxide is dispersed in a liquid binder, the dispersion binder were dried after application to the fiber sheet, a fine powder of the metal oxide from the fixed to the seat surface, the fine of the metal oxide on fixing surface of the powder by superimposing another fiber sheet, after it obtained by integrating the entire by needle punching, Torisa preparation of filter material that is thermally decomposed or vaporized binder by heat treatment. The two fiber sheet, a web of heat resistant fibers produced by pretreatment with needle punching, No placement claim 1 Symbol treated at either 200 to 250 ° C. Both fiber sheet before overlay both Manufacturing method. The liquid binder is polyvinyl alcohol dissolved in warm water, and water is added to the metal oxide fine powder and stirred to uniformly disperse, and then a predetermined amount of the liquid binder is added while stirring the dispersion. Or the manufacturing method of 2. The method according to claim 1 or 2, wherein one or both of the two fiber sheets are integrated by interposing a base fabric of heat-resistant fibers, and the base fabric is disposed on the inner surface or middle of the fiber sheet. After it is integrated overall by needle punching, process according to claim 1 or 2 wherein further laminating a porous membrane of vinylidene Motoju fat. After it is integrated overall by needle punching, process according to claim 1 or 2 wherein further coated hydrofluoric Motoju fat. Claims a dispersion binder liquid containing a fine powder of metal oxide to both adhere the two sheets of the fiber sheet surface is fixed a fine powder and then be integrated by bonding the fixation surface of both fine powder 3. The production method according to 1 or 2.

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