JP2007196083A - Flat membrane filter medium for suspension filter, and its manufacturing method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a flat membrane filter medium for suspension filter which can filter suspension only by water head of a tank header by dipping the filter medium in a filtering water tank storing various sewages, causes little clogging, has superior environmental protective property dispensing with the use of a flocculant and superior filtering performance while easy in handling, can enhance filtering capacity by sucking, has superior versatility and practicality, allows stripping of suspended substances on the surface by back-washing or physical scraping using a brush or a scraper, has superior durability, maintenability and stability of the filtering performance, and is continuously operable over a long period. <P>SOLUTION: This flat membrane filter medium for suspension has a porous layer, the layer having scrum structure formed of independent nuclear spaces serving as nuclei of porous spaces, and continuous fine spaces communicating multiple independent nuclear spaces with each another. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention is discharged from factories such as sewage or food factories generated at various construction and civil engineering sites such as lakes, ponds, rivers, etc. The present invention relates to a flat membrane filter material for a suspended water filter for filtering and purifying suspended water such as sewage, and a method for producing the same.

Conventionally, purification treatment of suspended water such as sewage generated at various construction works such as river works, sewage works, road works, etc. has been performed by combining a plurality of solid-liquid separators. For example, the following techniques are known for the purification of suspended water.
(Patent Document 1) includes “an inclined screen device into which raw water is introduced, and a rotating drum type solid-liquid separation device into which rough water is introduced by this inclined type screen device. The apparatus has a rotating drum into which the treated water of the inclined screen device is introduced, and the rotating drum has a thickness obtained by raising the substrate directly on the surface of the substrate made of woven fabric or knitted fabric. "Solid-liquid separation device" is described in which a filter cloth formed by forming naps of ultrafine fibers of 0.1 to 10 µm is mounted so that the filter layer is inside the rotating drum.
(Patent Document 2) states that “a water intake device that takes in raw water containing pollutants from the water area, and a continuous rotating drum type that filters the raw water taken by the water intake device and separates it into filtrate and filtrate. An agglomeration reaction device that agglomerates and aggregates the filtrate obtained by the filtration device and the rotary drum type continuous filtration device, and a filter cloth traveling type that extracts the aggregated flocked filtrate by the agglomeration reaction device. A water purification device comprising a dehydrator ”is described.
(Patent Document 3) states that “a filter cloth belt type dewatering device of a type in which a single filter cloth belt capable of filtering a slurry or sludge-like object to be dewatered is wound endlessly and sequentially transferred. A negative pressure dehydrating section for initially dehydrating the material to be dehydrated by applying suction negative pressure to the material to be dehydrated supplied to the upper surface side of the filter cloth belt from the lower surface side of the filter cloth belt; Pressure dehydration transfer that pressurizes between the pair of press rolls together with the filter cloth belt to dehydrate, and transfers the dehydrated process article to one press roll and peels it from the filter cloth belt. A pair of the cleaning part, the cleaning part for cleaning the filter cloth belt from which the processing object has been peeled off, and the cleaned filter cloth belt. It is equipped with an aperture part that squeezes between squeeze rolls Described filter cloth belt type dehydrator "that is.
JP-A-6-238110 JP-A-8-39098 JP 2001-170419 A

However, the above conventional technique has the following problems.
(1) The filter cloth of the solid-liquid separation device described in (Patent Document 1) forms a filter layer by napping of ultrafine fibers obtained by raising the substrate directly on the surface of the substrate made of woven fabric or knitted fabric. Therefore, there has been a problem that the filter layer is easily worn and lacks durability. In addition, there is a problem that clogging is likely to occur and cleaning is difficult, and maintenance and long life are lacking.
(2) In the rotary drum type continuous filtration device described in (Patent Document 2), filtration in which napped fibers having a thickness of about 0.1 to 20 μm lie in a substantially constant direction on the surface of a substrate made of woven fabric or knitted fabric. Since the material is used, it has the same problem as (Patent Document 1) that lacks durability, maintainability, and long life.
(3) In the filter cloth belt-type dehydrator described in (Patent Document 3), the filter cloth belt includes an outer surface layer constituting the upper surface, an inner surface layer constituting the lower surface, and an intermediate layer therebetween. The outer layer is composed of an ultrafine fiber layer that filters the material to be dehydrated, the intermediate layer is composed of a medium fine fiber layer that promotes the permeation of moisture, and the inner layer promotes water drainage. It is composed of a base fabric layer that is dense on the outer surface side and rough on the inner surface side, but is a three-layered felt material in which fiber layers formed of fibers with different fiber diameters are simply laminated. Filtration efficiency cannot be obtained, and it is difficult to remove suspended substances adhering to the surface. It must be immersed in washing water for cleaning or dehydration by pressure. Lack of maintainability and practicality It has been a problem that.
(4) (Patent Document 1) to (Patent Document 3) all use a woven fabric, a knitted fabric, or a non-woven filter cloth, and form a void only by adjusting a gap between fibers. Since the cross-sectional shape is basically circular, the contact area between fibers tends to be large and the porosity tends to be low, and the pore shape is not uniform, so it is difficult to obtain a uniform porosity and filtration. There was a problem that the performance is likely to vary.
Moreover, since the unevenness | corrugation on the surface of a filter cloth is large and the suspended substance adhering is hard to peel off, it had the subject that maintenance property and long-life property were missing.
(5) When the porous portion of the filter layer (outer surface layer) on the surface of the filter cloth is formed with fine pores, in order to ensure water permeability, the thickness must be reduced, and the physical properties of the brush, etc. It has a problem that it is weak to general cleaning, easily broken and lacks durability. In addition, if the thickness is increased to ensure durability, fine pores continue in the thickness direction, so suspended solids are likely to be clogged in the middle, resulting in reduced filtration performance in a short time, and practicality and reliability. It had the problem of lacking.
In addition, the surface coating of the conventional flat membrane filter is made by attaching a microporous film to the surface of the base material, so it is very weak and easily damaged by external cleaning. The entire structure is unusable and has a problem of lack of reliability and long life.

  The present invention has been made to solve the above-mentioned problems, and by immersing it in a filtered water tank or the like in which suspended water such as various sewage is stored, the suspended water is filtered only by tank header water pressure (water head pressure). Clogging is unlikely to occur, there is no need to use a flocculant, etc., environmental protection is excellent, handling is easy, filtration performance is improved, filtration capacity can be improved by suction, versatility, practical use In addition to excellent durability, it is possible to peel off suspended substances on the surface by backwashing or physical scraping with a brush or scraper, etc., and it has excellent durability and maintainability and can be operated continuously over a long period of time. Provision of a flat membrane filter medium for suspension water filters with excellent stability of filtration performance, and a flat membrane filter medium for suspension water filters that can form a uniform porous space with a simple process and is excellent in mass productivity. And an object thereof is to provide a manufacturing method.

In order to solve the above problems, the flat membrane filter medium for suspension water filter and the method for producing the same of the present invention have the following configurations.
The flat membrane filter for a suspended water filter according to claim 1 is a flat membrane filter for a suspended water filter provided with a porous layer, wherein the porous layer is an independent nucleus space serving as a nucleus of the porous space, And a scram structure formed by a continuous fine space communicating between the plurality of independent nuclear spaces.
This configuration has the following effects.
(1) Since the porous layer has a scram structure in which continuous microspaces (open cells) are formed around the closed space (closed cells) so as to connect the closed space to each other, Even if it is thick, the continuous fine space region that captures fine particles in the suspended water can be thinly formed, so the clogging of the porous layer is unlikely to occur, and the filtration performance is highly reliable and durable. Excellent in properties.
(2) Since the porous layer has a scram structure, even if the surface layer side of the porous layer is damaged during continuous use, it is possible to perform continuous filtration with the continuous fine space formed inside. It has excellent lifespan and can be applied to suspension water with high concentration, providing excellent reliability and versatility.

Here, the scrum structure is a mixture of a large-sized closed nucleus space (closed cell) that becomes the core of the porous space and a small continuous fine space (open cell) inside the porous layer. A structure in which a large number of continuous fine spaces are formed so as to connect each other, and the front surface and the back surface of the porous layer communicate with each other.
By making the cross-sectional shape of the nonwoven fabric fiber forming the porous layer irregular, a substantially uniform and continuous flow path can be formed along the fiber to form a continuous fine space, which is formed between the fibers. A porous layer having a scram structure can be formed by reliably communicating with the gap (independent nucleus space). As the material of the nonwoven fabric forming the porous layer, synthetic fibers such as polyamide, polyester, polyolefin, polyacrylonitrile, polyvinyl chloride, polyvinylidene chloride, polyvinyl alcohol (vinylon), and the like having an average fiber diameter of 3 to 25 μm are preferable. Used. In particular, polyester and polypropylene are preferable in terms of water resistance, chemical resistance, and weather resistance. As the average fiber diameter becomes thinner than 3 μm, handling tends to be difficult, and the mass productivity and durability of the nonwoven fabric tends to be lacking. As the fiber becomes thicker than 25 μm, the voids (independent core space) increase and the porosity increases. There is a tendency that the filtration performance tends to be lowered, both of which are not preferable.

  The continuous fine space can also be formed of a porous resin impregnated in at least the surface layer portion of the nonwoven fabric fiber layer. As a method of forming a continuous fine space with a porous resin, a foaming agent is mixed in the porous resin and foamed, or the porous resin does not dissolve in the porous resin but water or A method of mixing a dissolving agent in a dissolving solution such as hot water, sulfuric acid, hydrochloric acid, etc., impregnating and solidifying the fiber layer of the nonwoven fabric, and then dissolving the dissolving agent in the dissolving solution, heat or solvent in the porous resin There is a method in which a shrinking material that shrinks is mixed, impregnated into a non-woven fiber layer and solidified, and then the shrinking material is shrunk. Alternatively, inorganic or organic fine powders may be kneaded with a binder and integrated with the fiber layer of the surface layer of the nonwoven fabric by spraying or coating to form a continuous fine space in which the fine powders are joined in a network. .

Porous resins include polyvinyl chloride, polyvinyl alcohol, polyamide, polyethylene, polypropylene, polystyrene, cross-linked polyethylene, cross-linked polyprene, ABS resin, polyurethane, polycarbonate, poloacetal, polybutylene terephthalate, polyphenylene oxide, urea resin, epoxy Resin, silicon resin and the like are preferably used.
As the solubilizer, amylose, glucose, sodium chloride, calcium chloride, sodium hydroxide, naphthalene and the like are preferably used.
As the shrink material that shrinks by heat, stretched polyolefin, polyvinylidene chloride, polystyrene, polyvinyl chloride, and the like are preferably used. In addition, vinylon is preferably used as a shrinking material that shrinks when immersed in water.
These formation methods of continuous minute spaces may be used alone or in combination. By forming a porous layer with multiple combinations, pores with different dimensions and shapes can be easily formed and the porosity can be changed, so the filtration performance can be adjusted, and productivity and practical use Excellent in properties. In particular, when a foaming agent is mixed in a porous resin and foamed, and a method in which a dissolving agent or shrinkage material is mixed and dissolved or contracted in the porous resin, the foaming agent foams. A scram structure in which a large number of fine pores (continuous microspaces) are formed in the resin film so as to communicate with the large pores (independent nucleus spaces) formed by the above method can be obtained.

  The thickness of the porous layer is preferably 10 μm to 1000 μm. As the thickness of the porous layer becomes thinner than 10 μm, a sufficient continuous fine space cannot be secured, the filtration capacity is insufficient, and the entire porous layer can be quickly removed by physical washing with a brush or the like. It tends to be damaged, the effect of the scrum structure is insufficient and the life tends to be reduced, and as it becomes thicker than 1000 μm, the water permeability tends to be insufficient and the filtration efficiency tends to decrease, both of which are preferable. Absent. By setting the thickness of the porous layer in the range of 10 μm to 1000 μm, even if the surface layer side of the porous layer breaks, the inside becomes a new surface layer and can be continuously filtered in a continuous fine space. Excellent filtration performance reliability and long life.

The average pore diameter of the continuous fine space of the porous layer is 0.5 μm to 8 μm, preferably 1 μm to 4 μm. As the average pore diameter becomes smaller than 1 μm, clogging is likely to occur, and it tends to be difficult to filter a large amount of suspended water. As the average pore diameter becomes larger than 4 μm, the amount of water passing increases and the filtration performance increases. There is a tendency to decrease easily. Also, as the average pore diameter becomes smaller than 0.5 μm, the water permeability tends to be greatly reduced and the filtration efficiency tends to be lowered, and as it becomes larger than 8 μm, it is difficult to supplement the fine suspended substances. Therefore, the suspended substance is caught in the internal pores and becomes a closed state, which tends to be unable to be removed by backwashing or washing, both of which are not preferable.
In addition, the porous layer having a scram structure may be used alone or may be laminated with a nonwoven fabric or the like.

Flat membrane filter media for suspended water filters equipped with a porous layer having a scram structure can be washed by backwashing (flowing compressed air, purified water, etc. from the downstream side), A brush cleaning system that cleans the surface with a brush or brush, a water jet cleaning system that blows away the suspended substances (solid adhering substances) on the surface by ejecting medium or low pressure water from the nozzle, and a vacuum cleaner Such a suction system can be used for cleaning by a suction cleaning method for sucking a suspended substance (solid adhering substance) on the surface, a scraper cleaning method for scraping a suspended substance (solid adhering substance) on a surface by a scraper, and the like. Since gravity filtration can be performed, clogging hardly occurs, and suspended substances can be peeled off with a small external stimulus.
Moreover, since the membrane surface (porous layer) of the flat membrane filter medium for suspension water filter can be physically washed, it can be used for suspension water having a high concentration and is excellent in versatility. In addition, the suspended water adhering to the membrane surface can be peeled off in a coherent state and settled down to the bottom of a filtration tank, etc. by peeling cleaning such as brush cleaning and scraper cleaning, so that the concentration of suspended water becomes high Can be prevented, and a stable filtration flow rate can be obtained.
Since a pressure device is not required at the time of filtration, it is excellent in energy saving, the entire filtration device can be reduced in size and weight, and mass productivity and handleability can be improved.

The invention according to claim 2 is the flat membrane filter material for a suspended water filter according to claim 1, wherein the porous layer has a cross-sectional shape that is deformed by one or more convex portions and / or concave portions. It has the structure formed with the fiber.
With this configuration, in addition to the operation of the first aspect, the following operation is provided.
(1) Since the fiber forming the porous layer has a cross-sectional shape that is deformed by one or more convex portions and / or concave portions, a substantially uniform continuous fine space can be formed in the porous layer. Excellent filtration performance uniformity.

Here, as a method for deforming the cross-sectional shape of the fiber with the convex portion or the concave portion, a method of drawing the fiber from a mold having a cross-sectional shape having a desired convex portion or concave portion is preferably used. Thereby, the fiber by which the cross-sectional shape deformed by the convex part and the recessed part was formed continuously can be obtained, and a protruding item | line and a concave item can be formed in parallel with the longitudinal direction of a fiber. Further, by twisting the fiber at the time of stretching, the ridges and the ridges can be formed in a spiral shape. By stretching the fiber in the liquid, the deformed cross-sectional shape can be reliably maintained, and the productivity is excellent.
The cross-sectional shape of the fiber does not need to be uniform in the longitudinal direction, and one or more convex portions and / or concave portions that are regularly or irregularly independent may be formed on the outer periphery of the fiber.

  The size and number of the convex portions and concave portions depend on the fiber diameter, but when the fiber diameter is 10 μm to 25 μm, the diameter of the arc-shaped convex portions and concave portions is preferably 2 μm to 5 μm. The number of convex portions and concave portions is preferably 2 to 8. As the diameter of the convex part and the concave part becomes smaller than 2 μm, or the number of convex parts and concave parts becomes less than two, the effect of deforming becomes insufficient, the water permeability tends to decrease, and the filtration efficiency tends to decrease. As the diameter of the protrusions and recesses becomes larger than 5 μm, or the number of protrusions and recesses exceeds 8, the cross-sectional shape becomes difficult to maintain and the productivity tends to decrease, and the porosity Tends to be high and the filtration performance tends to decrease, both of which are not preferred.

Invention of Claim 3 is the flat membrane filter medium for suspension water filters of Claim 1, Comprising: The said porous layer is a nonwoven fabric and the porous resin which the fiber layer of the said nonwoven fabric was impregnated, It has the structure formed integrally by.
With this configuration, in addition to the operation of the first aspect, the following operation is provided.
(1) Since the porous layer is integrally formed of a nonwoven fabric and a porous resin impregnated into the nonwoven fabric fiber layer, the scram structure is excellent in durability and physical properties such as backwashing or brush or scraper are used. It is possible to peel off suspended substances on the surface by an effective scraping, etc., and the continuous operation can be performed for a long period of time, and the stability of the filtration performance is excellent.
Here, the porous resin is formed by impregnating and solidifying a non-woven fiber layer with a foamable resin or the like and breaking the cell by pulling or needling and then foaming the same as described in claim 1. can do. Moreover, the method of dissolving a solubilizer with a solution, and the method of shrinking a shrinkable material with heat or a solvent can also be used. Further, a method of laminating a melt-foamed resin mixed with a foaming agent (NaCl, NaHCO _3, etc.) on the nonwoven fabric, and then pulling and destroying the cells to foam, a nonwoven fabric in a casting syrup mixed with foaming agents having different particle sizes There is a method of impregnating, solidifying, pulling or needling, then immersing in a solution (water, etc.) and foaming.

Invention of Claim 4 is a flat membrane filter material for suspension water filters of any one of Claim 1 thru | or 3, Comprising: It forms in the downstream of the said porous layer and the said porous layer. Further, the intermediate fiber layer of the nonwoven fabric having a higher porosity than the porous layer, the support layer formed on the downstream side of the intermediate fiber layer, and the voids than the intermediate fiber layer formed on the downstream side of the support layer And a non-woven base fiber layer having a high rate.
With this configuration, in addition to the operation of any one of claims 1 to 3, the following operation is provided.
(1) By making the porous layer on the upstream side having a scram structure finer, it is possible to reliably capture particles in the suspended water at the surface portion and prevent intrusion into the inside. By roughening the lower fiber layer on the side, suspended substances adhering to the surface of the porous layer can be easily removed by backwashing or physical peeling. It is possible to use it and is excellent in maintainability and practicality.
(2) By changing the porosity so that the porosity increases from the porous layer side that is the upstream side to the lower fiber layer side that is the downstream side during filtration, it is ensured even for fine suspended substances It can be captured and filtered at the surface of the porous layer, and the filtered water of the suspended water can be quickly discharged from the lower fiber layer side, and the filtration efficiency is excellent.
(3) By having the support layer formed between the intermediate fiber layer and the lower fiber layer, the entire structure can be reinforced to prevent vertical and horizontal deformation, and the durability is excellent.
(4) The overall thickness and strength can be adjusted by the lower fiber layer, and when washing with a scraper, brush, etc., impact can be absorbed by its cushioning property, and the porous layer is damaged. While becoming difficult, filtered water can be freely moved and discharged, and water permeability can be improved.

Here, as the nonwoven fabric for forming the intermediate fiber layer and the lower fiber layer, the same nonwoven fabric as that for forming the porous layer described above is preferably used.
Basis weight of the flat film filter media for suspending water filter 500g / m ² ~1000g / m ² is preferred. As the basis weight becomes smaller than 500 g / m ^2, it becomes difficult to withstand the water pressure repeatedly applied over a long period of time, and the durability tends to decrease, and as it becomes larger than 1000 g / m ² , mass productivity decreases. It is easy to do, and neither is preferable.
The support layer can be formed by disposing a reinforcing material such as a woven fabric, a net, or other porous membrane between the intermediate fiber layer and the lower fiber layer. A monofilament or multifilament fabric base fabric is preferably used as the reinforcing material, but a spun fabric may be used. Further, as the material of the reinforcing material, the same material as that of the above-mentioned nonwoven fabric is preferably used. In the case of a net, a composite of stainless steel wire and polyester may be arranged in a mesh shape vertically and horizontally.

The apparent density of the flat membrane filter media for suspending water filters 0.35g / cm ³ ~0.55g / cm ³ are preferred. As the apparent density becomes smaller than 0.35 g / cm ^3, the filtration area in contact with the suspended water becomes insufficient, and the filtration efficiency tends to decrease. As the apparent density becomes larger than 0.55 g / cm ³ , Tends to be insufficient and it becomes difficult to filter a large amount of suspended water, both of which are not preferred.

The flat membrane filter medium for a suspended water filter preferably has an air passage amount of 1 (cm ³ / s) / cm ² to 10 (cm ³ / s) / cm ² when a pressure difference of 98 kPa is applied. As the air flow rate becomes smaller than 1 (cm ³ / s) / cm ² , the water flow rate becomes insufficient, and it becomes difficult to filter a large amount of suspended water, and 10 (cm ³ / s) / As it becomes larger than cm ^{2, the} amount of fibers that come into contact with the suspended water becomes insufficient, and the filtration efficiency tends to decrease, which is not preferable.

The manufacturing method of the flat membrane filter material for suspension water filters of Claim 5 is a manufacturing method of the flat membrane filter material for suspension water filters of Claim 2 or 4, Comprising: At least one convex part and / or a recessed part The porous layer is formed by three-dimensionally entangled fibers having a modified cross-sectional shape.
This configuration has the following effects.
(1) A scram structure having a mesh-like continuous fine space can be simplified by forming a porous layer by three-dimensionally interlacing fibers having a cross-sectional shape deformed by one or more convex portions and / or concave portions. It can be formed into an excellent mass productivity.
Here, a needle punch, a water jet needle, or the like is preferably used as a method of entanglement of the fibers in three dimensions.

Invention of Claim 6 is a manufacturing method of the flat membrane filter material for suspension water filters of Claim 3 or 4, Comprising: The formation process of the said porous layer uses resin which mixed the foaming agent of the said nonwoven fabric. A resin impregnation step for impregnating the surface layer portion of the fiber layer and a resin foaming step for foaming the resin are provided.
This configuration has the following effects.
(1) After impregnating the surface layer portion of the nonwoven fiber layer with a resin mixed with a foaming agent in the resin impregnation step, the resin foams the porous layer with the nonwoven fiber layer by simply foaming the resin. It is possible to form a porous layer having a scrum structure in which the resin is integrated and has excellent durability, and is excellent in mass productivity.
(2) Since the formation process of the porous layer has a resin impregnation process for impregnating a resin in which a foaming agent is mixed with the surface layer portion of the nonwoven fabric fiber layer and a resin foaming process for foaming the resin, In addition, a porous layer having a scrum structure can be easily formed, and the productivity is excellent.

Here, the resin may be a one-component type or a two-component mixed type. Moreover, what is necessary is just to produce foaming in the temperature range which does not exceed the melting transition point of the nonwoven fabric used as a base material. In addition, what foams at normal temperature is easy to handle and has excellent mass productivity. The foaming agent may be organic or inorganic, but it is preferable to control the formulation so that continuous foam suitable as a filter medium is formed.
The resin can be impregnated into the fiber by being applied or sprayed onto the nonwoven fabric, and a porous layer having a scram structure in which the fiber layer of the nonwoven fabric and the resin are integrated can be formed.

Invention of Claim 7 is a manufacturing method of the flat membrane filter material for suspension water filters of Claim 3 or 4, Comprising: The formation process of the said porous layer is foaming which mixed the melt | dissolution agent melt | dissolved in a solvent. A resin impregnation step of impregnating the surface layer portion of the fiber layer of the nonwoven fabric with resin, a resin foaming step of foaming the foamable resin, and a dissolution step of dissolving the dissolving agent by immersing the fiber layer in the solvent; And having a configuration provided.
This configuration has the following effects.
(1) Since the foaming resin impregnated in the surface layer portion of the fiber layer by the resin impregnation step is mixed with a dissolving agent that dissolves in the solvent, the foaming resin is foamed by the resin foaming step, and then the fiber is formed by the dissolution step. The solubilizer can be dissolved simply by immersing the layer in a solvent, and fine pores (continuous microspaces, continuous microbubbles) are formed in the resin layer around the pores (closed core spaces, closed cells) generated by foaming. A porous layer having a scram structure can be formed.
Here, the foamable resin is obtained by mixing a foaming agent with the same resin as described above. The solubilizer may be any one that does not dissolve in the resin as described above but dissolves in a specific solvent such as water, hot water, sulfuric acid, hydrochloric acid, or the like.

Invention of Claim 8 is a manufacturing method of the flat membrane filter material for suspension water filters of Claim 3 or 4, Comprising: The formation process of the said porous layer mixes the shrinkage | contraction material shrink | contracted with a heat | fever or a solvent. A resin impregnation step of impregnating the surface layer portion of the non-woven fiber layer with the foamed resin, a resin foaming step of foaming the foamable resin, and heating or immersing the fiber layer in the solvent to shrink the shrinkable material And a shrinking step.
This configuration has the following effects.
(1) Since the expandable resin impregnated in the surface layer portion of the fiber layer by the resin impregnation step is mixed with a shrinkable material that contracts by heat or a solvent, the expandable resin is foamed by the resin foaming step, and then the contraction step The shrinkable material can be shrunk simply by heating the fiber layer or immersing it in a solvent. By forming fine pores (continuous microspaces) in the resin layer around the pores (independent core space) generated by foaming A porous layer having a scrum structure can be formed.
Here, the foamable resin is obtained by mixing a foaming agent with the same resin as described above. The shrink material may be any material that shrinks when heated or immersed in a solvent as described above.

According to invention of Claim 1, it has the following effects.
(1) Since the porous layer has a scram structure formed by a plurality of independent nuclear spaces and continuous fine spaces connecting them, a continuous fine space region for capturing fine particles in the suspension water is thinly formed. It is possible to provide a flat membrane filter medium for a suspended water filter, which is capable of forming a porous layer with a high thickness, which is capable of forming a thick porous layer, which is less likely to be clogged with a porous layer, excellent in filtration performance, and thick. Can do.
(2) A porous layer having a scram structure can be continuously filtered by a continuous fine space formed inside even if the surface layer is damaged during continuous use, and has an excellent long life and concentration. Therefore, it is possible to provide a flat membrane filter medium for a suspension water filter that can cope with a concentrated suspension water having excellent reliability and versatility.

According to invention of Claim 2, in addition to the effect of Claim 1, it has the following effects.
(1) A scram structure having a substantially uniform continuous fine space is formed in the porous layer by forming the porous layer with fibers having a cross-sectional shape deformed by one or more convex portions and / or concave portions. Therefore, it is possible to provide a flat membrane filter medium for a suspended water filter that is excellent in the uniformity of filtration performance.

According to invention of Claim 3, in addition to the effect of Claim 1, it has the following effects.
(1) Since a porous layer formed by integrating a porous resin with a nonwoven fabric fiber layer has excellent scram structure durability, the surface is suspended by backwashing or physical scraping with a brush or scraper. It is possible to provide a flat membrane filter medium for a suspended water filter that can easily and reliably peel turbid substances and has excellent filtration performance that can be continuously operated for a long period of time.

According to invention of Claim 4, in addition to the effect of any one of Claims 1 thru | or 3, it has the following effects.
(1) To provide a flat membrane filter material for a suspended water filter excellent in filtration performance capable of reliably capturing particles in suspended water at the surface portion of a porous layer having a scram structure and preventing entry into the interior. it can.
(2) The lower fiber layer having a high porosity can be used to reliably capture and filter fine suspended solids on the surface of the porous layer on the upstream side during filtration, and to filter the filtered suspension water. It is possible to provide a flat membrane filter medium for a suspended water filter that can be discharged quickly from the side and has excellent filtration efficiency.
(3) By making the upstream porous layer finer and making the downstream lower fiber layer coarser, suspended substances adhering to the surface of the porous layer by backwashing or physical peeling can be easily obtained. Therefore, it is possible to provide a flat membrane filter material for a suspended water filter that is easy to remove, clogging is less likely to occur, and can be used continuously for a long period of time.
(4) Due to the cushioning property of the lower fiber layer, it is possible to provide a flat membrane filter medium for a suspension water filter that can absorb the impact during washing with a scraper, a brush, etc., and can reduce damage to the porous layer. .

According to invention of Claim 5, it has the following effects.
(1) A porous layer having a scram structure having excellent filtration performance and durability can be easily formed by three-dimensionally interlacing fibers having a cross-sectional shape deformed by one or more convex portions and / or concave portions. The manufacturing method of the flat membrane filter medium for suspension water filters excellent in mass productivity which can be performed can be provided.

According to invention of Claim 6, it has the following effects.
(1) Mass production that can form a porous layer with excellent durability in which a nonwoven fabric fiber layer and a foamed porous resin are integrated in only two steps of a resin impregnation step and a resin foaming step. An excellent method for producing a flat membrane filter medium for a suspended water filter can be provided.

According to invention of Claim 7, it has the following effects.
(1) After the foamable resin impregnated in the surface layer portion of the fiber layer by the resin impregnation step is foamed by the resin foaming step, the dissolving agent mixed with the foamable resin simply by immersing the fiber layer in the solvent by the dissolution step Can form a porous layer having a scram structure with excellent filtration performance and durability by forming a continuous fine space in the resin layer around the independent core space generated by foaming It is possible to provide a method for producing a flat membrane filter medium for a suspended water filter having excellent reliability.

According to invention of Claim 8, it has the following effects.
(1) After the foamable resin impregnated in the surface layer portion of the fiber layer by the resin impregnation step is foamed by the resin foaming step, the fiber layer is mixed with the foamable resin only by being heated or immersed in a solvent by the shrinking step. The shrinkable material can be shrunk, and a continuous fine space can be formed in the resin layer around the independent core space generated by foaming to obtain a porous layer having a scram structure with excellent filtration performance and durability. It is possible to provide a method for producing a flat membrane filter medium for a suspended water filter that is excellent in mass productivity and reliability.

(Embodiment 1)
A flat membrane filter medium for a suspended water filter and a method for producing the same according to Embodiment 1 of the present invention will be described below with reference to the drawings.
FIG. 1 is a schematic cross-sectional view of an essential part showing a flat membrane filter medium for a suspended water filter in the first embodiment.
In FIG. 1, 1 is a flat membrane filter medium for suspension water filter according to Embodiment 1 of the present invention, and 2 is a flat membrane filter medium for suspension water filter having a scram structure formed by deforming the cross-sectional shape of fibers of the nonwoven fabric. Reference numeral 1 denotes a porous layer, 3 denotes an intermediate fiber layer of a flat membrane filter medium 1 for a suspended water filter having a higher porosity than the porous layer 2 formed of a nonwoven fabric on the downstream side of the porous layer 2, and 4 denotes a woven fabric and a net The support layer of the flat membrane filter medium 1 for suspension water filter formed on the downstream side of the intermediate fiber layer 3 with other reinforcing material such as a porous membrane, 5 is an intermediate fiber layer formed of a nonwoven fabric on the downstream side of the support layer 4 4 is a lower fiber layer having a porosity higher than 4.

  Nonwoven fabrics for forming the porous layer 2, the intermediate fiber layer 3, and the lower fiber layer 5 of the flat membrane filter medium 1 for suspension water filter are polyamide, polyester, polyolefin, polyacrylonitrile, polyvinyl chloride, polyvinylidene chloride, polyvinyl Synthetic fibers such as alcohol (vinylon) are used. The average fiber diameter of each layer can be appropriately selected according to the porosity and the like. The average fiber diameter of the synthetic fibers forming the porous layer 2 was 3 μm to 25 μm. As the average fiber diameter becomes thinner than 3 μm, handling becomes difficult, and the mass productivity and durability of the nonwoven fabric tend to be lacking. This is because it has been found that there is a tendency to make it easier. In addition, it turned out that polyester and a polypropylene are preferable from the surface of water resistance, chemical resistance, and weather resistance.

Basis weight of the aqueous suspension filtering spur membrane filter medium 1 was formed in ^{500g / m 2 ~1000g / m 2} . As the basis weight becomes smaller than 500 g / m ^2, it becomes difficult to withstand the water pressure repeatedly applied over a long period of time, and the durability tends to decrease, and as it becomes larger than 1000 g / m ² , mass productivity decreases. This is because it has been found that there is a tendency to make it easier.
The support layer 4 was formed by disposing a reinforcing material such as a woven fabric, a net, or other porous membrane between the intermediate fiber layer 3 and the lower fiber layer 5. As the reinforcing material, a monofilament or multifilament fabric base fabric is preferably used, but a spun fabric may be used. In addition, as the material of the reinforcing material, the same material as that of the above-mentioned nonwoven fabric is preferably used. In the case of a net, a composite of stainless steel wire and polyester may be arranged in a mesh shape vertically and horizontally.

Apparent density of the aqueous suspension filtering spur membrane filter medium 1 is formed in the ^{0.35g / cm 3 ~0.55g / cm 3} . As the apparent density becomes smaller than 0.35 g / cm ^3, the filtration area in contact with the suspended water becomes insufficient, and the filtration efficiency tends to decrease. As the apparent density becomes larger than 0.55 g / cm ³ , This is because it has been found that there is a tendency that it becomes difficult to filter a large amount of suspended water.
The flat membrane filter medium 1 for a suspended water filter was formed such that the air passage amount when a pressure difference of 98 kPa was applied was 1 (cm ³ / s) / cm ² to 10 (cm ³ / s) / cm ² . . As the air flow rate becomes smaller than 1 (cm ³ / s) / cm ² , the water flow rate becomes insufficient, and it becomes difficult to filter a large amount of suspended water, and 10 (cm ³ / s) / This is because it has been found that the amount of fibers that come into contact with the suspended water becomes insufficient and the filtration efficiency tends to decrease as it becomes larger than cm ² .

  The average pore diameter of the continuous fine space (open cell) of the porous layer 2 was 0.5 μm to 8 μm, preferably 1 μm to 4 μm. As the average pore diameter becomes smaller than 1 μm, clogging tends to occur, and it tends to be difficult to filter a large amount of suspended water. This is because a tendency to decrease easily was observed. Also, as the average pore diameter becomes smaller than 0.5 μm, the water permeability tends to be greatly reduced and the filtration efficiency tends to be lowered, and as it becomes larger than 8 μm, it is difficult to supplement the fine suspended substances. As a result, it was found that the suspended substance is caught in the internal pores and becomes blocked, and cannot be removed by backwashing or washing.

  The thickness of the porous layer 2 was 10 μm to 1000 μm. As the thickness of the porous layer 2 becomes thinner than 10 μm, a sufficient continuous fine space cannot be secured, the filtration capability becomes insufficient, and the porous layer 2 can be obtained in a short time by physical washing with a brush or the like. The whole tends to be damaged, the effect of the scrum structure is insufficient and the life tends to be reduced, and as it becomes thicker than 1000 μm, the water permeability is insufficient and the filtration efficiency tends to decrease. This is because I understand. By making the thickness of the porous layer 2 in the range of 10 μm to 1000 μm, even if the surface layer side of the porous layer 2 is damaged, the inside becomes a new surface layer and filtration is continuously performed in a continuous fine space. Excellent filtration performance reliability and long life.

  This flat membrane filter medium 1 for a suspended water filter can be subjected to gravity filtration, is less likely to clog, and can release suspended substances with a small external stimulus. It can be cleaned by a brush cleaning system, a water jet cleaning system, a suction cleaning system, a scraper cleaning system, etc., and can be used for suspension water having a high concentration and is excellent in versatility. In addition, the suspended substances attached to the surface of the porous layer 2 can be separated in a coherent state by sedimentation cleaning such as brush cleaning or scraper cleaning, and settled on the bottom of a filtration tank or the like. Can be prevented, and a stable filtration flow rate can be obtained.

Since no pressure device is required for filtration, energy saving is excellent, the entire filtration device can be reduced in size and weight, and mass productivity and handleability can be improved.
Without the use of flocculants, etc., the minerals contained in rivers and lakes can be removed, and only the suspended solids can be removed for purification treatment, which can be discharged into rivers as fresh water. Excellent environmental protection because it can. Moreover, even if suspended substances in suspension water adhere to the surface of the porous layer 2 of the flat membrane filter medium 1 for a suspension water filter, the filtration efficiency does not decrease, and excellent filtration performance can be maintained. Excellent in practicality and reliability.

Next, the porous layer of the flat membrane filter medium for a suspended water filter will be described in detail.
FIG. 2 is a schematic perspective view showing fibers forming a porous layer of the flat membrane filter medium for a suspended water filter in the first embodiment.
FIG. 2A is an example in which a plurality of convex portions 11 are formed on the circumference of the fiber 10 that forms the porous layer 2, and FIG. 2B shows the fiber 10 a that forms the porous layer 2. FIG. 2C shows an example in which a plurality of substantially spherical convex portions 11 b are formed on the outer peripheral surface of the fiber 10 b forming the porous layer 2. This is an example.
These convex portions 11, 11a, and 11b can be formed by passing the fibers 10, 10a, and 10b between rolling rollers that have irregularities corresponding to the convex portions 11, 11a, and 11b formed on the surface.

The size of the protrusions 11, 11a, 11b depends on the fiber diameter of the fibers 10, 10a, 10b, but when the fiber diameter is 10 μm to 25 μm, the diameter of the protrusions 11, 11a, 11b is 2 μm to 5 μm. . As the diameter of the convex parts 11, 11a, 11b becomes smaller than 2 μm, the effect of deforming becomes insufficient, the water permeability tends to decrease and the filtration efficiency tends to decrease, and the convex parts 11, 11a, 11b This is because it has been found that as the diameter becomes larger than 5 μm, it is difficult to maintain the cross-sectional shape and the productivity tends to decrease, and the porosity tends to increase and the filtration performance tends to decrease.
In the step of forming the porous layer 2 of the flat membrane filter medium 1 for a suspended water filter, the fibers 10, 10a, 10b having a cross-sectional shape deformed by one or more convex portions 11, 11a, 11b are made into a needle punch or a water jet needle. By forming the porous layer 2 by entanglement in three dimensions by a method such as the above, it is possible to form a substantially uniform continuous fine space that communicates with the independent nucleus space. The average pore diameter of the pores) can be formed to the aforementioned 0.5 μm to 8 μm, preferably 1 μm to 4 μm.

Next, a modification of the fiber forming the porous layer will be described with reference to the drawings. FIG. 3 is a schematic cross-sectional view showing a modification of the cross-sectional shape of the fibers forming the porous layer of the flat membrane filter medium for a suspended water filter in the first embodiment.
FIG. 3 (a) is an example in which five convex portions 11c are formed on the outer periphery of the fiber 10c, and FIG. 3 (b) is an example in which four convex portions 11d are formed on the outer periphery of the fiber 10d. FIG. 3C is an example in which three convex portions 11e are formed on the outer periphery of the fiber 10e, and FIG. 3D is an example in which four concave portions 11f are formed on the outer periphery of the fiber 10f. 3 (e) is an example in which three concave portions 11g are formed on the outer periphery of the fiber 10g, and FIG. 3 (f) is an example in which two concave portions 11h are formed on the outer periphery of the fiber 10h.

By stretching the fiber from a mold having a cross-sectional shape similar to the cross-sectional shape of the fibers 10c to 10h shown in FIG. 3, the cross-sectional shape of the fiber can be made irregular, and the convex shape is continuous in the longitudinal direction of the fiber. Strips and recesses can be formed. Further, by twisting the fiber at the time of stretching, the ridges and the ridges can be formed in a spiral shape as shown in FIG. By stretching the fiber in the liquid, the deformed cross-sectional shape can be reliably maintained, and the productivity is excellent.
In FIG. 3, the shape of the cross-sectional shape is changed by two to five convex portions 11c to 11e and concave portions 11f to 11h, but the number of convex portions 11c to 11e and concave portions 11f to 11h is two to two. Eight can be formed. As the number of the convex portions 11c to 11e and the concave portions 11f to 11h is less than two, the effect of deforming becomes insufficient, the water permeability tends to decrease, and the filtration efficiency tends to decrease. As the number of 11e and recesses 11f to 11h increases from eight, it becomes difficult to maintain the cross-sectional shape and the productivity tends to decrease, and the porosity tends to increase and the filtration performance tends to decrease. It is because it was understood.
Each of the fibers 10 to 10h shown in FIGS. 2 and 3 may be used alone or in combination of a plurality of types.

According to the flat membrane filter material for a suspended water filter in the first embodiment configured as described above, the following action is obtained.
(1) By narrowing the eyes of the upstream porous layer 2 having a scram structure, particles in the suspended water can be reliably captured at the surface portion to prevent entry into the interior, and the filtration performance is excellent.
(2) By adjusting the porosity of each layer so that the porosity increases from the porous layer 2 side that is the upstream side to the lower fiber layer 5 side that is the downstream side during filtration, However, it can be reliably captured and filtered on the surface of the porous layer 2, and the filtered water of the suspended water can be quickly discharged from the lower fiber layer 5 side, and the filtration efficiency is excellent.
(3) Suspension adhered to the surface of the porous layer 2 by backwashing or physical peeling by narrowing the upstream porous layer 2 and coarsening the downstream lower fiber layer 5 Substances can be easily removed, clogging is unlikely to occur, it can be used continuously for a long time, and it is excellent in maintainability and practicality.
(4) By having the support layer 4 formed between the intermediate fiber layer 3 and the lower fiber layer 5, the entire structure can be reinforced to prevent vertical and horizontal deformation and excellent durability.
(5) The entire thickness and strength of the flat membrane filter medium 1 for a suspended water filter can be adjusted by the lower fiber layer 5, and when it is washed with a scraper, a brush or the like, the cushioning property can absorb an impact. In addition, it is difficult for the porous layer 2 to be broken, and the filtered water can be freely moved and discharged, thereby improving water permeability.
(6) The fibers 10 to 10h forming the porous layer 2 have a cross-sectional shape modified by one or more convex portions 11 to 11e and concave portions 11f to 11h, so that the porous layer 2 is substantially uniform. A continuous fine space can be formed, and the uniformity of filtration performance is excellent.
(7) Since the porous layer 2 has a scram structure in which substantially uniform continuous microspaces are formed in multiple layers, even if the fibers 10 to 10h are torn on the surface of the porous layer 2, the inner side of the porous layer 2 is further increased. Filtration can be continuously performed by the continuous fine space formed by the fibers 10 to 10h, and the filtration performance is excellent in reliability and long life.

According to the manufacturing method of the flat membrane filter material for suspension water filter in Embodiment 1 comprised as mentioned above, it has the following effects.
(1) By forming the porous layer 2 by three-dimensionally interlacing fibers 10 to 10h having a cross-sectional shape deformed by one or more convex portions 11 to 11e and concave portions 11f to 11h, a continuous fine space is formed. The scrum structure can be easily formed and is excellent in mass productivity.

(Embodiment 2)
A flat membrane filter for a suspended water filter and a method for producing the same in Embodiment 2 of the present invention will be described below with reference to the drawings.
FIG. 4 (a) is a schematic cross-sectional view of an essential part showing a porous layer of a flat membrane filter medium for suspension water filter according to the second embodiment, and FIG. 4 (b) is a flat membrane filter medium for suspension water filter according to the second embodiment. It is a principal part cross-section figure which shows the formation process of the porous layer of.
In FIG. 4 (a), 2a is a porous layer having a scram structure of a flat membrane filter medium for a suspended water filter in the embodiment 2, and 15 is impregnated into a non-woven fiber layer (not shown) forming the porous layer 2a. The porous resin 15a is integrated with the non-woven fabric, 15a is an independent nucleus space serving as a nucleus of the porous space of the porous layer 2a, and 15b is a continuous fine space communicating between the plurality of independent nucleus spaces 15a.
The intermediate fiber layer 3, the support layer 4, and the lower fiber layer 5 (not shown) are the same as those in the first embodiment, and thus the description thereof will be omitted. ), The intermediate fiber layer 3, the support layer 4, and the lower fiber layer 5 are laminated.

Next, the formation process of the porous layer having a scram structure will be described in detail.
In FIG. 4 (b), 16 is polyvinyl chloride, polyvinyl alcohol, polyamide, polyethylene, polypropylene, polystyrene, crosslinked polyethylene, crosslinked polyprene, ABS resin, polyurethane, polycarbonate, polo acetal, poly, which forms the porous resin 15. Amylose, glucose, sodium chloride, calcium chloride, sodium hydroxide, mixed in a foaming resin such as butylene terephthalate, polyphenylene oxide, urea resin, epoxy resin, silicone resin, etc., and dissolved in a solvent such as water, hot water, sulfuric acid, hydrochloric acid, It is a solubilizer such as naphthalene.
First, in the resin impregnation step, the foaming resin in which the foaming agent is mixed with the above-mentioned resin is mixed with the solubilizing agent 16 that does not dissolve in the resin but dissolves in the above-mentioned solvent, and is applied to the fiber layer of the nonwoven fabric serving as the substrate. Alternatively, the fibers are impregnated by spraying.

Next, as shown in FIG. 4B, in the resin foaming step, the foamable resin is foamed to form a large-sized independent nucleus space 15a.
Finally, the fiber layer integrated with the porous resin 15 is immersed in the aforementioned solvent in the dissolving step, and between the spaces 15a and 15b and between the outer and inner sides of the porous layer 2a and the spaces 15a and 15b. The resin film is broken and the dissolving agent 16 is dissolved to form a continuous fine space 15b that is finer than the independent nucleus space 15a shown in FIG. A scram structure in which a large number of continuous fine spaces 15b are formed in the surrounding resin film so as to communicate with the independent core space 15a formed by foaming of the foaming agent can be obtained. As a result, even if the surface layer side of the porous layer 2a is broken during continuous use, continuous filtration can be performed by the continuous microspace 15b formed on the inner side, and it is excellent in long life and has a high concentration. It can cope with muddy water and has excellent reliability and versatility.
The resin for mixing the foaming agent may be a one-component type or a two-component mixed type. Moreover, what is necessary is just to produce foaming in the temperature range which does not exceed the melting transition point of the nonwoven fabric used as a base material. In addition, what foams at normal temperature is easy to handle and has excellent mass productivity. The foaming agent may be organic or inorganic, but it is preferable to control the formulation so that continuous foam suitable as a filter medium is formed. Further, in the resin foaming step, the continuous fine space 15b is formed in a reliable communication with the independent nucleus space 15a by selecting the dissolving agent 16 that dissolves at a temperature that is the same as or lower than the temperature at which the foamable resin is foamed. be able to.

Next, modified examples of the flat membrane filter medium for a suspended water filter according to Embodiment 2 of the present invention will be described below with reference to the drawings.
FIG. 5 (a) is a schematic cross-sectional view of an essential part showing a modification of the porous layer of the flat membrane filter medium for suspension water filter in the second embodiment, and FIG. 5 (b) is for suspension water filter in the second embodiment. It is a principal part cross-sectional schematic diagram which shows the formation process of the modification of the porous layer of a flat membrane filter medium.
In FIG. 5 (a), the modification of the porous layer of the suspension membrane filter flat membrane filter is different from the second embodiment in that the shape of the continuous fine space 15c of the porous layer 2b is formed in a substantially cylindrical shape. The function is the same as that of the porous layer 2a of the flat membrane filter medium for the suspended water filter in the second embodiment.
Further, in FIG. 5 (b), the modification process of the porous layer of the flat membrane filter medium for suspension water filter is different from that of the second embodiment in that in the resin impregnation process, the fiber layer of the nonwoven fabric serving as the substrate is used. The impregnated foamable resin is mixed with a heat-shrinkable shrinkable material 16a instead of the dissolving agent 16, and the fiber layer integrated with the porous resin 15 is heated and shrunk instead of the dissolving step. This is a point having a shrinking step of shrinking the material 16a.
As the shrink material 16a, stretched polyolefin, polyvinylidene chloride, polyvinyl chloride or the like is preferably used. The amount of shrinkage of the shrinkable material 16a can be adjusted as appropriate by selecting the heating temperature. In the resin foaming process, by selecting the shrinkable material 16a that shrinks at the same temperature as or lower than the temperature at which the foamable resin is foamed, the continuous microspace 15c can be reliably communicated with the independent core space 15a. it can. Although omitted in FIG. 5 (a), the contracted material 16a after contraction actually remains inside the continuous fine space 15c.

In the present embodiment, the shape of the solubilizer 16 is formed in a substantially spherical shape, and the shape of the shrinkable material 16a is formed in a substantially cylindrical shape. However, the present invention is not limited to this, and is not limited to this. It can be formed in various shapes. The size of the solubilizer 16 and the shrinkage material 16a can be appropriately selected according to the size of the continuous microspaces 15b and 15c formed in the porous layers 2a and 2b. By filtering the size of the dissolving agent 16 and the shrinkage material 16a so that the average pore diameter of the continuous microspaces 15b and 15c is 0.5 μm to 8 μm, preferably 1 μm to 4 μm, suitable filtration performance is obtained. be able to.
In addition, instead of the solvent 16 that dissolves in the solvent and the shrink material 16a that shrinks by heat, vinylon that shrinks by the solvent is used as the shrink material, and after the resin foaming step, the fiber layer is immersed in the solvent to obtain the shrink material. It is also possible to form a continuous fine space by performing a contraction step for contraction.
Moreover, you may combine the formation method of these porous layers 2a and 2b, and the method of forming the porous layer 2 by making the cross-sectional shape of the fiber of the nonwoven fabric demonstrated in Embodiment 1 irregular.
The porous layers 2 a and 2 b may be formed directly on the surface layer side of the intermediate fiber layer 3 instead of forming the fiber layer laminated on the intermediate fiber layer 3. In this case, the porous layers 2a and 2b and the intermediate fiber layer 3 can be integrated, and durability can be improved.

According to the flat membrane filter medium for the suspended water filter configured as described above, in addition to the function of the first embodiment, the following function is provided.
(1) The porous layers 2a and 2b have a scram structure in which continuous microspaces 15b and 15c are formed so as to connect the independent nucleus spaces 15a around the independent nucleus space 15a. Even if the entire 2b is formed thick, the regions of the continuous fine spaces 15b and 15c that capture fine particles in the suspended water can be formed thin, so that the porous layers 2a and 2b are not easily clogged. Excellent filtration performance reliability and durability.
(2) Since the porous layers 2a and 2b are integrally formed with the nonwoven fabric and the porous resin 15 impregnated into the nonwoven fabric fiber layer, the porous layers 2a and 2b are excellent in durability and are backwashed or by brushing or scraper. Suspended substances on the surface can be peeled off by physical scraping, etc., continuous operation is possible for a long period of time, and the stability of filtration performance is excellent.
(3) Since the porous layers 2a and 2b have a scram structure in which a large number of continuous microspaces 15b and 15c are formed in the surrounding resin film so as to communicate with the independent nucleus space 15a, the porous layers 2a and 2b Even if the continuous microspaces 15b and 15c are destroyed on the surface, it can be continuously filtered by the continuous microspaces 15b and 15c continuously formed inside thereof, and the filtration performance is reliable and the service life is long. Excellent in properties.

According to the manufacturing method of the flat membrane filter material for a suspended water filter according to the second embodiment configured as described above, in addition to the functions of the first embodiment, the following functions are provided.
(1) When the foaming resin to be impregnated in the surface layer portion of the fiber layer by the resin impregnation step is mixed with the dissolving agent 16 that dissolves in the solvent, the foaming resin is foamed by the resin foaming step, and then the dissolution step. The solubilizer 16 can be dissolved simply by immersing the fiber layer in a solvent, and the continuous fine space 15b can be formed and communicated with the resin layer around the independent nucleus space 15a generated by foaming, and has a scram structure. The porous layer 2a can be formed.
(2) When the shrinkable material 16a that shrinks by heat is mixed with the foamable resin impregnated in the surface layer portion of the fiber layer by the resin impregnation process, after the foamable resin is foamed by the resin foaming process, The shrinkable material 16a can be shrunk only by heating the fiber layer, and the continuous fine space 15c can be formed and communicated with the resin layer around the independent nucleus space 15a generated by foaming, and the scram structure is provided. The porous layer 2b can be formed.

  The present invention is capable of filtering suspended water only by tank header water pressure (water head pressure) by immersing it in a filtered water tank or the like in which suspended water such as various sewage is stored. No need to use chemicals, etc. Excellent environmental protection, easy handling, excellent filtration performance, improved filtration capacity by suction, excellent versatility and practicality, backwash or brush, scraper, etc. The suspended solids on the surface can be peeled off by physical scraping, etc., and it has excellent durability and maintainability, can be operated continuously over a long period of time, and has a stable filtration performance. Providing a membrane filter medium and a method for producing a flat membrane filter medium for a suspended water filter that is capable of forming a uniform porous space with a simple process and that is excellent in mass productivity, can be provided over a long period of time. Stability of possible filtration performance continuous operation I, durability of the apparatus, an excellent filtering device maintainability can be realized.

Cross-sectional schematic diagram of relevant parts showing a flat membrane filter medium for a suspended water filter according to Embodiment 1. The schematic perspective view which shows the fiber which forms the porous layer of the flat membrane filter medium for suspension water filters in Embodiment 1 Schematic cross-sectional view showing a modification of the cross-sectional shape of the fiber forming the porous layer of the flat membrane filter medium for the suspended water filter in the first embodiment (A) Schematic cross-sectional view of the relevant part showing the porous layer of the flat membrane filter medium for suspension water filter in the second embodiment (b) The step of forming the porous layer of the flat membrane filter medium for suspension water filter in the second embodiment is shown. Cross-sectional schematic diagram of relevant parts (A) Schematic cross-sectional view of the main part showing a modification of the porous membrane filter medium for suspension water filter in Embodiment 2 (b) Modification of porous layer of the membrane filter medium for suspension water filter in Embodiment 2 Cross-sectional schematic diagram of the relevant part showing the example formation process

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Flat membrane filter medium for suspension water filters 2, 2a, 2b Porous layer 3 Intermediate fiber layer 4 Support layer 5 Lower fiber layer 10, 10a, 10b, 10c, 10d, 10e, 10f, 10g, 10h Fiber 11, 11a, 11b , 11c, 11d, 11e Convex part 11f, 11g, 11h Concave part 15 Porous resin 15a Independent nucleus space 15b, 15c Continuous fine space 16 Solvent 16a Contracting material

Claims (8)

  A flat membrane filter medium for a suspended water filter provided with a porous layer, wherein the porous layer is an independent nucleus space serving as a nucleus of a porous space, and a continuous fine space that communicates between the plurality of independent nucleus spaces. A flat membrane filter material for a suspended water filter, characterized by having a scram structure formed by:   The flat membrane filter material for a suspended water filter according to claim 1, wherein the porous layer is formed of fibers having a cross-sectional shape deformed by one or more convex portions and / or concave portions.   2. The flat membrane for a suspended water filter according to claim 1, wherein the porous layer is integrally formed of a nonwoven fabric and a porous resin impregnated in a fiber layer of the nonwoven fabric. Filter media.   The porous layer, an intermediate fiber layer of a nonwoven fabric having a higher porosity than the porous layer formed on the downstream side of the porous layer, a support layer formed on the downstream side of the intermediate fiber layer, and The suspension water according to any one of claims 1 to 3, further comprising a non-woven base fiber layer having a higher porosity than the intermediate fiber layer formed on the downstream side of the support layer. Flat membrane filter media for filters.   5. The method for producing a flat membrane filter medium for a suspended water filter according to claim 2, wherein fibers having a cross-sectional shape deformed at one or more convex portions and / or concave portions are entangled three-dimensionally to form the porous material. A method for producing a flat membrane filter medium for a suspended water filter, comprising forming a porous layer.   The method for producing a flat membrane filter material for a suspended water filter according to claim 3 or 4, wherein the porous layer forming step impregnates a surface layer portion of the fiber layer of the nonwoven fabric with a resin mixed with a foaming agent. A method for producing a flat membrane filter for a suspended water filter, comprising: an impregnation step; and a resin foaming step of foaming the resin.   It is a manufacturing method of the flat membrane filter material for suspension water filters of Claim 3 or 4, Comprising: In the formation process of the said porous layer, the foamable resin which mixed the melt | dissolution material melt | dissolved in a solvent is used for the fiber layer of the said nonwoven fabric. A suspension comprising: a resin impregnation step for impregnating the surface layer portion; a resin foaming step for foaming the foamable resin; and a dissolving step for dissolving the dissolving material by immersing the fiber layer in the solvent. A method for producing a flat membrane filter medium for turbid water filters. 5. The method for producing a flat membrane filter material for a suspended water filter according to claim 3 or 4, wherein the porous layer is formed of a foamable resin mixed with a shrinkable material that shrinks by heat or a solvent. A resin impregnation step for impregnating a surface layer portion of the layer; a resin foaming step for foaming the foamable resin; and a shrinking step for shrinking the shrinkable material by heating or immersing the fiber layer in the solvent. A method for producing a flat membrane filter medium for a suspended water filter.

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