JP2019034304A - Substrate for semipermeable membrane for membrane separation activated sludge treatment, filter membrane, and module - Google Patents

Abstract

To provide a substrate for a semipermeable membrane for membrane separation activated sludge treatment, which is excellent in solvent resistance and the strength of which is hardly decreased when the top of the substrate for the semipermeable membrane is coated with a coating liquid for forming the semipermeable membrane.SOLUTION: In a substrate for a semipermeable membrane for membrane separation activated sludge treatment, the substrate for the semipermeable membrane contains drawn polyester fibers, undrawn polyester fibers serving as binder fibers, core sheath type polyester composite fibers having copolymer polyester used as a sheath part, and wet heat adhesive fibers.SELECTED DRAWING: None

Description

  The present invention relates to a support for a semipermeable membrane for membrane separation activated sludge treatment, a filtration membrane, and a module.

  Semipermeable membranes are widely used in the fields of desalination of seawater, water purifiers, food concentration, wastewater treatment, ultrapure water production for medical use and semiconductor cleaning, such as blood filtration. The separation functional layer of the semipermeable membrane is composed of a porous resin such as a cellulose resin, a polysulfone resin, a polyacrylonitrile resin, a fluorine resin, or a polyester resin. However, since these porous resins alone are inferior in mechanical strength, filtration is a composite form in which a semipermeable membrane is provided on one side of a support for a semipermeable membrane made of a fibrous base material such as a nonwoven fabric or a woven fabric. A membrane is used. In the semipermeable membrane support, a surface on which the semipermeable membrane is provided is referred to as an “application surface”.

  One of the usage forms of these semipermeable membranes and filtration membranes is a membrane separation activated sludge treatment method (Membrane Bioreactor, MBR). The membrane-separated activated sludge treatment method is widely used since the quality of treated water is stable and maintenance is easy when treating organic sewage. In the membrane separation activated sludge treatment method, after removing contaminants in the sewage, the organic matter in the sewage is decomposed and removed by activated sludge in the biological treatment tank (aeration tank) and immersed in the biological treatment tank. The mixed solution is subjected to solid-liquid separation with an apparatus, and the permeated filtrate is discharged as treated water. The membrane separation part in such a membrane separator is aerated by an aeration operation to prevent minerals such as sand, sludge, and other solids from colliding violently during use, or to supply oxygen to activated sludge and clogging. Since the bubbles violently collide with the film surface, it is required to have strength enough to withstand such an impact.

  In addition, the filtration membrane is used in a modular form. Typical modules in the sheet-like filtration membrane are a flat membrane type module and a spiral type module. A typical module in a tubular filtration membrane is a tubular / tubular module (see, for example, Non-Patent Document 1). In the flat membrane module, a filtration membrane is used by adhering and fixing to a frame material made of a resin such as polypropylene, acrylonitrile, butadiene, styrene, or a synthetic resin (ABS resin). For adhesion and fixation to the frame material, heat fusion treatment, ultrasonic fusion treatment, or the like is generally performed. In particular, in recent years, the number of cases of processing by ultrasonic fusion processing has increased due to the simplicity of the apparatus. However, the conventional semipermeable membrane support does not consider adhesion to the frame material, has poor adhesion, and the frame material and the semipermeable membrane support can be easily peeled off or filtered during use. There has been a problem that the film falls off the frame material.

  Examples of a general support for semipermeable membrane include a support for semipermeable membrane containing olefin fibers such as polyethylene and polypropylene. For example, it is formed from a support for a semipermeable membrane obtained by heat-treating a composite fiber using polypropylene as a core material and polyethylene as a sheath material (see, for example, Patent Document 1), and wet heat-adhesive fibers such as the olefin composite fiber and vinyl alcohol. A semipermeable membrane support (see, for example, Patent Document 2) has been proposed. When these filtration membranes provided with a semipermeable membrane on a semipermeable membrane support containing olefin fibers are bonded to the frame material by ultrasonic fusion treatment, they adhere, but the semipermeable membrane support and the frame material Adhesiveness with was not sufficient.

  In the tubular / tubular module, a tubular base or mandrel is used, the side edges are partially overlapped with each other, and the tape-shaped semipermeable membrane support is spirally wound and overlapped. Are fused by heat fusion treatment, ultrasonic fusion treatment, etc. to produce a tubular semipermeable membrane support, and the filtration is provided with a semipermeable membrane outside or inside the tubular semipermeable membrane support. A plurality of membranes are bundled to form a module. In order to wind the tape-shaped semipermeable membrane support spirally, the application surface of the semipermeable membrane support and the non-application surface opposite to the application surface are fused in the overlapped portion. Since the semipermeable membrane support containing olefin fibers is easily fused, it has excellent adhesive strength between the coated surface and the non-coated surface of the semipermeable membrane support, and it is easy to produce a tubular semipermeable membrane support. However, since the part where the semipermeable membrane support is superposed and fused is formed into a film, it is difficult for the semipermeable film to bite into the coated part, and the semipermeable membrane and the semipermeable membrane support In some cases, the semipermeable membrane peeled off due to insufficient adhesion.

  Another common semipermeable membrane support is a semipermeable membrane support containing stretched polyester fibers and binder polyester fibers. For example, the support for a semipermeable membrane containing a stretched polyester fiber and a core-sheath type polyester composite fiber (see, for example, Patent Document 3), the melting point of the stretched polyester fiber, the polyolefin fiber, and the sheath is 120 ° C. or more and 150 ° C. or less. A semi-permeable membrane support containing a core / sheath polyester composite fiber (see, for example, Patent Document 4), a core / sheath type having a melting point of 125 ° C. or higher and 160 ° C. or lower between a stretched polyester fiber, an unstretched polyester fiber, and a sheath portion. A semipermeable membrane support (for example, see Patent Document 5) containing a polyester composite fiber has been proposed.

  The support for a semipermeable membrane proposed in Patent Document 3 achieves the effect that the strength and formation are improved by containing the stretched polyester fiber and the core-sheath type polyester composite fiber. The adhesive strength between the semipermeable membrane and the semipermeable membrane support in the tubular semipermeable membrane support has not been studied at all.

  In patent document 4, evaluation which adhere | attaches the support body for semipermeable membranes to a frame material by the heat-fusion process in 200 degreeC is performed. And since the support body for semipermeable membranes contains polyolefin fiber, the adhesive strength with a frame material is raised. However, as described above, when the support for the semipermeable membrane containing the olefin fiber and the frame material are bonded by the ultrasonic fusion treatment, the adhesion is made between the support for the semipermeable membrane and the frame material. Was not enough.

  In the semipermeable membrane support of Patent Document 5, the air permeability of the nonwoven fabric is specified while maintaining sufficient strength by containing a core-sheath type polyester composite fiber whose melting point of the sheath is 125 ° C. or higher and 160 ° C. or lower. It becomes possible to make it into a range, and the effect of suppressing the shrinkage of width and the generation of wrinkles during film formation is achieved. Moreover, the effect of improving an intensity | strength is achieved by using an unstretched polyester fiber together. However, when the inventors of the present invention have studied, a support for a semipermeable membrane comprising a stretched polyester fiber, an unstretched polyester fiber, and a core-sheath type polyester composite fiber having a sheath having a melting point of 125 ° C. or higher and 160 ° C. or lower. However, the adhesiveness with the frame material may be insufficient.

  Further, by containing a stretched polyester fiber, an unstretched polyester fiber, and a core-sheath type polyester composite fiber having a copolymer transition polyester having a glass transition point of 40 to 80 ° C. as a sheath part, the adhesive strength and the semi-transparent property to the frame material are obtained. A semipermeable membrane support for membrane-separated activated sludge treatment that has excellent adhesion strength between the coated surface and non-coated surface of the membrane support and also has excellent adhesion to the semipermeable membrane has been disclosed (for example, Patent Documents). 6 and 7). However, in the semipermeable membrane support of Patent Documents 6 and 7, when the coating liquid for forming the semipermeable membrane is applied on the semipermeable membrane support, the strength of the semipermeable membrane support is low. There was a case of decline.

JP 2001-17842 A JP 2012-250223 A JP 2010-194478 A JP 2012-101213 A JP 2013-220382 A Japanese Patent No. 6038369 Japanese Patent No. 6038370

Sewerage Membrane Processing Technology Conference, “Guidelines for Introducing Membrane Processing Technology into Sewers,” Second Edition, [online], March 2011, [Search January 6, 2016], Internet <URL: http: // www. mlit. go. jp / common / 000146906. pdf>

  An object of the present invention is to provide a semipermeable membrane for membrane separation activated sludge treatment that is excellent in solvent resistance and is less likely to decrease in strength when a coating liquid for forming a semipermeable membrane is applied on a support for a semipermeable membrane. It is to provide a support.

  As a result of intensive studies to solve the above problems, the following invention has been found.

(1) A semi-permeable membrane support for membrane separation activated sludge treatment, wherein the semi-permeable membrane support comprises a stretched polyester fiber, an unstretched polyester fiber as a binder fiber, and a core sheath having a copolymer polyester as a sheath. A support for a semipermeable membrane for membrane separation activated sludge treatment comprising a polyester-type polyester composite fiber and a wet heat adhesive fiber.

(2) The support for a semipermeable membrane for membrane separation activated sludge treatment according to the above (1), wherein the wet heat adhesive fiber is at least one selected from the group of vinyl alcohol fiber and ethylene-vinyl alcohol fiber.

(3) The above (1), wherein the content of the binder fiber is 20 to 50% by mass and the content of the wet heat adhesive fiber is 1 to 5% by mass with respect to the entire fiber contained in the support for the semipermeable membrane. Or the support body for semipermeable membranes for membrane separation activated sludge treatment as described in (2).

(4) The membrane-separated activated sludge according to any one of (1) to (3), wherein the content of unstretched polyester fiber is 5 to 30% by mass with respect to the entire fiber contained in the semipermeable membrane support. Semipermeable membrane support for processing.

(5) A filtration membrane for membrane separation activated sludge treatment, in which a semipermeable membrane is provided on the support for membrane separation activated sludge treatment semipermeable membrane according to any one of (1) to (4) above.

(6) A module using the membrane separation activated sludge treatment membrane according to (5) above.

(7) The module according to (6), wherein the module is at least one selected from the group consisting of a flat membrane module, a tube module, and a tubular module.

  The support for a semipermeable membrane for membrane separation activated sludge treatment of the present invention is excellent in solvent resistance, and the strength decreases when a coating liquid for forming a semipermeable membrane is applied on the support for a semipermeable membrane. The effect that it is hard to do can be achieved.

It is the schematic which showed the method of adhere | attaching the support body for semipermeable membranes and an ABS resin board in evaluation of the support body for semipermeable membranes for membrane separation activated sludge processes. It is the schematic which showed the method of measuring the adhesive strength of the support body for semipermeable membranes and an ABS resin board in evaluation of the support body for semipermeable membranes for membrane separation activated sludge processes. It is the schematic which showed the method of adhere | attaching the application surface surface of a semipermeable membrane support body, and a non-application surface in evaluation of the support body for semipermeable membranes for membrane separation activated sludge processes. It is the schematic which showed the method of measuring the adhesive strength of the application surface of a semipermeable membrane support body, and a non-application surface in evaluation of the support body for semipermeable membranes for membrane separation activated sludge processes. In the evaluation of a semipermeable membrane support for membrane separation activated sludge treatment, a method for measuring the adhesive strength of a semipermeable membrane provided on the part where the coated surface and non-coated surface of the semipermeable membrane support are fused. It is the shown schematic.

  In the present invention, the filtration membrane means that a coating liquid that is a raw material of the separation functional layer is applied to one side of the support for a semipermeable membrane for membrane separation activated sludge treatment, and the semipermeable membrane for water treatment is applied. The composite is formed and has a semipermeable membrane provided on one side of the semipermeable membrane support. Examples of the material for the separation functional layer include vinyl chloride resin (PVC), polysulfone (PS), polyvinylidene fluoride (PVDF), polyethylene (PE), cellulose acetate (CA), and polyacrylonitrile (PAN). ) Type, polyvinyl alcohol (PVA) type, polyimide (PI) type and the like. In particular, PVC systems have been used for semipermeable membranes for membrane separation activated sludge treatment. On the semipermeable membrane support, a coating solution, which is a solution in which a polymer material as a raw material is dissolved, is applied and gelled to form a microporous membrane. Hereinafter, the process of coating and forming the separation functional layer on the semipermeable membrane support is referred to as “film formation”.

  The filtration membrane is used in a modular form. Typical modules in the sheet-like filtration membrane are a flat membrane type module and a spiral type module. A typical module in a tubular filtration membrane is a tubular / tubular module.

  In the flat membrane module, polypropylene, acrylonitrile, butadiene, styrene copolymer synthetic resin is used with the non-coated surface, which is the opposite surface of the coated surface of the semipermeable membrane support, as the frame material bonding surface. A filter membrane is bonded and fixed to a frame material made of a resin such as (ABS resin). For adhesion and fixation to the frame material, heat fusion treatment, ultrasonic fusion treatment, or the like is generally performed.

  In the tubular / tubular module, a tubular substrate or mandrel is used, and the side edges of the semipermeable membrane support are partially overlapped with each other, and the tape-shaped semipermeable membrane support is wound spirally. The overlapped portion is fused by heat fusion treatment, ultrasonic fusion treatment or the like to produce a tubular semipermeable membrane support, and the semipermeable membrane is provided outside or inside the tubular semipermeable membrane support. A plurality of filtration membranes provided with the above are bundled into a module.

  The support for a semipermeable membrane for membrane separation activated sludge treatment of the present invention comprises a stretched polyester fiber, an unstretched polyester fiber as a binder fiber, a core-sheath polyester composite fiber having a copolymer polyester as a sheath, and wet heat adhesiveness It is characterized by containing a fiber. By including a non-stretched polyester fiber and heat calendering, it is possible to obtain a semipermeable membrane support having high strength. In addition, by including a core-sheath type polyester composite fiber having a copolymer polyester as a sheath part, the semipermeable material is excellent in the adhesive strength between the support for a semipermeable membrane and the frame material and the adhesive strength between the coated surface and the non-coated surface. A membrane support can be obtained. However, the core-sheath polyester composite fiber having the copolymer polyester as a sheath part may be deteriorated in adhesiveness when exposed to a coating solution. In this invention, it discovered that there existed an effect which supplements the fall of the adhesion | attachment of a core sheath polyester composite fiber by further adding wet heat adhesive fiber as a binder fiber.

  The wet heat-adhesive fiber used in the present invention is less susceptible to loss of adhesiveness in a short time of solvent treatment such as coating and forming a semipermeable membrane on a semipermeable membrane support, and it can be used for a semipermeable membrane with a small content. Since it is possible to improve the strength of the support, the adhesive strength between the semipermeable membrane support and the frame material and the decrease in the adhesive strength between the coated and non-coated surfaces due to the formation of a binder fiber film This makes it possible to compensate for the decrease in the adhesion of the core-sheath polyester composite fiber. That is, in the present invention, the semipermeable membrane support is composed of a stretched polyester fiber, an unstretched polyester fiber as a binder fiber, a core-sheath polyester composite fiber having a copolymer polyester as a sheath, and a wet heat adhesive fiber. It has excellent solvent resistance, strong adhesion strength between the semipermeable membrane support and the frame material, and strong adhesion strength between the coated surface and the non-coated surface, and the semipermeable membrane support and the semipermeable membrane. A support for a semipermeable membrane for membrane separation activated sludge treatment having excellent adhesion strength with a membrane can be obtained.

  In the present invention, as the unstretched polyester fiber used as the binder fiber, a polyester such as polyethylene terephthalate, polytrimethylene terephthalate, polybutylene terephthalate and a copolymer based on the polyester is used at a spinning speed of 800 to 1,200 m / min. Examples include spun unstretched fibers. These unstretched polyester fibers are heat-pressure fused by thermal calendering, whereby a high strength semipermeable membrane support can be obtained.

  In the present invention, the inclusion of the core-sheath type polyester composite fiber allows the frame material and the semipermeable membrane support to be in close contact during the heat fusion treatment or the ultrasonic fusion treatment during the production of the flat membrane module. The support for a semipermeable membrane having improved properties and high adhesive strength with the frame material can be obtained. In addition, when manufacturing a tubular semipermeable membrane support in a tubular / tubular module, the adhesion between the coated surface of the semipermeable membrane support and the non-coated surface is improved, and the semipermeable membrane support is coated. A support for a semipermeable membrane having high adhesive strength between the surface and the non-coated surface can be obtained. Furthermore, by including a core-sheath type polyester composite fiber having a core portion that is not thermally melted as a part of the binder fiber, the coating of the surface of the semipermeable membrane support due to the heat melting of the binder fiber is suppressed, and the coating solution can penetrate. It is possible to develop strength without impairing the properties.

  In the present invention, the sheath of the core-sheath type polyester composite fiber used as the binder fiber is a copolyester. The copolyester includes a terephthalic acid component and an ethylene glycol component, and an isophthalic acid component, an adipic acid component, a sebacic acid component, a naphthalenedicarboxylic acid component, a diethylene glycol component, a 1,4-butanediol component, and an aliphatic group Examples thereof include a copolyester containing at least one component selected from the group of lactone components. This copolyester may be amorphous or crystalline.

  In the present invention, the sheath of the core-sheath polyester composite fiber used as the binder fiber is preferably a copolymer polyester having a glass transition point of 40 to 80 ° C. When the glass transition point of the copolyester in the sheath part of the core-sheath polyester composite fiber is 40 ° C. or higher, the mechanical strength of the sheath part is increased, so that the glass transition point is lower than 40 ° C. The adhesive strength between the semipermeable membrane support and the frame material and the adhesive strength between the coated surface and the non-coated surface of the semipermeable membrane support are preferably increased. On the other hand, when the glass transition point is 80 ° C. or lower, the adhesion between the semipermeable membrane support and the frame material and the coating surface of the semipermeable membrane support when heat fusion treatment or ultrasonic fusion treatment is performed. Compared with the case where the glass transition point exceeds 80 ° C., the adhesive strength between the semipermeable membrane support and the frame material and the coated surface of the semipermeable membrane support This is preferable because the adhesive strength of the non-coated surface is improved.

  In the present invention, the core of the core-sheath type polyester composite fiber is a polyester whose main repeating unit is alkylene terephthalate, and is preferably polyethylene terephthalate having high heat resistance.

  In the present invention, the cross-sectional shape of the core-sheath polyester composite fiber is not particularly limited, but is preferably circular. Further, the ratio of the core part to the sheath part is preferably in the range of core / sheath = 30/70 to 70/30, more preferably 40/60 to 60/40, in terms of volume ratio.

  In this invention, the support body for semipermeable membranes excellent in solvent resistance can be obtained by containing a wet heat adhesive fiber. In the present invention, the wet heat adhesive fiber refers to a fiber that swells and gels when heated in the presence of moisture and exhibits adhesiveness, and is a wet papermaking method that is a preferred method for producing the semipermeable membrane support of the present invention. The wet-heat adhesive fibers are swollen and gelled when the dryer is dried during wet papermaking, and the other fibers are firmly fixed by drying the sheet in this state by hot-pressure drying.

  Examples of wet heat adhesive fibers used in the present invention include vinyl alcohol fibers and ethylene-vinyl alcohol fibers. As vinyl alcohol fibers and ethylene-vinyl alcohol fibers, vinyl alcohol fibers, ethylene-vinyl alcohol fibers, composite fibers made of vinyl alcohol and other resins, ethylene-vinyl alcohol and other resins And the like. Examples of the composite fiber include core-sheath type (core-shell type), parallel type (side-by-side type), and radial split type.

  In the case of a composite fiber, the resin combined with vinyl alcohol fiber and ethylene-vinyl alcohol fiber is not particularly limited. For example, polypropylene, high density polyethylene (HDPE), low density polyethylene (LDPE), linear low density Examples thereof include olefin resins such as polyethylene (LLDPE), polyacrylic resins, polyester resins, and polyamide resins. Among these, vinyl alcohol monofilament, ethylene-vinyl alcohol monofilament, polypropylene fiber as the core, core-sheath type composite fiber with the ethylene-vinyl alcohol fiber as the sheath, polyester fiber as the core, ethylene- A core-sheath type composite fiber having a vinyl alcohol fiber as a sheath is preferably used.

  In this invention, it is preferable that content of a binder fiber is 20-50 mass%, and it is more preferable that it is 30-50 mass%. If the content of the binder fiber is less than 20% by mass, the adhesive strength between the fibers tends to be insufficient, the surface of the support for a semipermeable membrane tends to fluff, and the applicability of the semipermeable membrane may be impaired. On the other hand, if the binder fiber content exceeds 50% by mass, the surface of the semipermeable membrane support is likely to be formed into a film by melting the binder fiber, and the frame material melted by heat fusion treatment, ultrasonic fusion treatment, etc. By making it difficult to bite into the semipermeable membrane support, the adhesive strength between the semipermeable membrane support and the frame material may be reduced. In addition, in the tubular semipermeable membrane support, the part where the coated surface and the non-coated surface of the semipermeable membrane support are fused is easily formed into a film, and the semipermeable membrane is less likely to bite into the fused portion. The adhesive strength between the semipermeable membrane support and the semipermeable membrane may be reduced.

  In the present invention, the content of the unstretched polyester fiber is preferably 5 to 30% by mass, and more preferably 10 to 25% by mass. When the content of the unstretched polyester fiber is less than 5% by mass, the semipermeable membrane support may be wrinkled during the heat calendar process. On the other hand, if the amount exceeds 30% by mass, the surface of the semipermeable membrane support is likely to become a film, and the frame material melted by heat fusion treatment or ultrasonic fusion treatment becomes difficult to bite into the semipermeable membrane support. In some cases, the adhesive strength between the semipermeable membrane support and the frame material may be reduced. In addition, in the tubular semipermeable membrane support, the part where the coated surface and the non-coated surface of the semipermeable membrane support are fused is easily formed into a film, and the semipermeable membrane is less likely to bite into the fused portion. The adhesive strength between the semipermeable membrane support and the semipermeable membrane may be reduced.

  In this invention, it is preferable that content of wet heat adhesive fiber is 1-5 mass%, and it is more preferable that it is 2-4 mass%. When the content of the wet heat adhesive fiber is less than 1% by mass, the strength of the semipermeable membrane support after forming the semipermeable membrane may be lowered. On the other hand, if the amount exceeds 5% by mass, the surface of the semipermeable membrane support is likely to be formed into a film by melting the wet heat adhesive fibers, and the frame material melted by heat fusion treatment or ultrasonic fusion treatment is used for the semipermeable membrane. By making it difficult to bite into the support, the adhesive strength between the semipermeable membrane support and the frame material may be reduced. In addition, in the tubular semipermeable membrane support, the part where the coated surface and the non-coated surface of the semipermeable membrane support are fused is easily formed into a film, and the semipermeable membrane is less likely to bite into the fused portion. The adhesive strength between the semipermeable membrane support and the semipermeable membrane may be reduced.

  In the present invention, the fiber diameter of the binder fiber is preferably 2 to 30 μm, more preferably 5 to 27 μm, and still more preferably 7 to 25 μm. When binder fibers having a fiber diameter of less than 2 μm are used, the strength of the semipermeable membrane support may be insufficient. On the other hand, when a binder fiber having a fiber diameter of more than 30 μm is used, fiber dispersion at the time of papermaking deteriorates, the formation of the support for the semipermeable membrane tends to be uneven, and the film forming property of the separation functional layer is improved. It may be damaged.

  In the present invention, the fiber length of the binder fiber is preferably 1 to 15 mm, more preferably 3 to 12 mm, and further preferably 3 to 10 mm. When the fiber length is less than 1 mm, the strength of the semipermeable membrane support may decrease. When the fiber length exceeds 15 mm, the fiber dispersibility tends to decrease, and the formation of the semipermeable membrane support may be reduced. It tends to be non-uniform and may impair the film-forming property of the separation functional layer.

  In the support for a semipermeable membrane for membrane separation activated sludge treatment of the present invention, a stretched polyester fiber is used as a main fiber. When the nonwoven fabric contains binder fibers, by incorporating the step of raising the temperature up to the softening point or melting temperature (melting point) or higher of the binder fibers in the method for producing a semipermeable membrane support for membrane separation activated sludge treatment, The binder fiber improves the mechanical strength of the support for a semipermeable membrane for membrane separation activated sludge treatment. In the step of raising the temperature, the stretched polyester fiber does not soften or melt, and forms a skeleton of the semipermeable membrane support as the main fiber. Examples of the stretched polyester fiber include polyesters whose main repeating unit is alkylene terephthalate, but polyethylene terephthalate having high heat resistance is preferable. The cross-sectional shape of the fiber is preferably circular. However, fibers having irregular cross-sections such as T-type, Y-type, and triangle can also be contained within a range that does not hinder other characteristics in order to prevent back-through and smoothness of the coated surface.

  The fiber diameter of the stretched polyester fiber is preferably 2 to 30 μm, more preferably 5 to 27 μm, and still more preferably 7 to 25 μm. When fibers having a fiber diameter of less than 2 μm are used, the strength of the semipermeable membrane support may be insufficient. On the other hand, when fibers having a fiber diameter of more than 30 μm are used, fiber dispersion during papermaking deteriorates, the formation of the semipermeable membrane support tends to be uneven, and the film forming property of the separation functional layer is impaired. There is a case.

  The fiber length of the stretched polyester fiber is not particularly limited, but is preferably 1 to 15 mm, more preferably 3 to 12 mm, and still more preferably 3 to 10 mm. When the fiber length is less than 1 mm, the strength of the semipermeable membrane support may decrease. When the fiber length exceeds 15 mm, the fiber dispersibility tends to decrease, and the formation of the semipermeable membrane support may be reduced. It tends to be non-uniform and may impair the film-forming properties of the semipermeable membrane.

  In the support for a semipermeable membrane for membrane separation activated sludge treatment of the present invention, fibers other than the above-described stretched polyester fiber and binder fiber may be added as necessary. Specifically, examples of the synthetic fiber include polyolefin-based, polyamide-based, polyacrylic-based, vinylidene, polyvinyl chloride, benzoate, polychlor, and phenol-based fibers. Natural fiber includes hemp pulp, cotton linter, lint; regenerated fiber is lyocell fiber, rayon, cupra; semi-synthetic fiber is acetate, triacetate, promix; inorganic fiber is alumina fiber, alumina -Fibers such as silica fiber, rock wool, glass fiber, micro glass fiber, zirconia fiber, potassium titanate fiber, alumina whisker, and aluminum borate whisker. In addition to the above fibers, wood fibers such as softwood pulp and hardwood pulp, woody materials such as straw pulp, bamboo pulp, and kenaf pulp and herbs can be used as plant fibers. Moreover, as long as the said fiber is a range which does not inhibit liquid permeability and air permeability, it may be fibrillated at all. Furthermore, pulp fibers obtained from waste paper, waste paper, and the like can also be used. Moreover, the fiber which has irregular cross sections, such as T type, Y type, and a triangle, can also be contained.

  The support for a semipermeable membrane for membrane separation activated sludge treatment of the present invention preferably has a glass transition point derived from a core-sheath polyester composite fiber by differential scanning calorimetry. When the content of the core-sheath polyester composite fiber is low, or when the crystallinity of the core-sheath polyester composite fiber is increased by thermal calendering, it becomes a support for a semipermeable membrane where the glass transition point cannot be determined. There is. The semipermeable membrane support for which the glass transition point is required is compared with the semipermeable membrane support and the frame material for which the glass transition point is not required. The adhesive strength between the coated surface and the non-coated surface of the membrane support is excellent.

  In addition, the glass transition point of the sheath part of the core-sheath type polyester composite fiber in the present invention and the support for the semipermeable membrane for membrane separation activated sludge treatment is a differential scanning calorimeter (manufactured by Perkin Elmer, apparatus name: DSC8500). And measured at a heating rate of 10 ° C./min. The glass transition point was defined as the temperature at which the straight line equidistant in the vertical axis direction from the extended straight line of each baseline intersects with the curve of the stepwise change portion of the glass transition.

The basis weight of the membrane separation activated sludge process for semipermeable membrane support of the present invention is preferably from 30 to 250 g / ^{m 2,} more preferably ^{40~230g / m 2, 50~200g / m} 2 is more preferable. If it is less than 30 g / m ² , the strength of the semipermeable membrane support may be insufficient. In addition, if it exceeds 250 g / m ² , the module or unit may be used in order to increase the flow resistance or to increase the thickness of the semipermeable membrane support so as to accommodate a prescribed amount of semipermeable membrane. It is necessary to increase the size.

  The thickness of the support for a semipermeable membrane for membrane separation activated sludge treatment of the present invention is preferably 60 to 300 μm, more preferably 70 to 270 μm, and still more preferably 80 to 250 μm. When the thickness exceeds 300 μm, the area of the semipermeable membrane that can be incorporated into the unit is reduced, and as a result, the life of the semipermeable membrane may be shortened. On the other hand, when the thickness is less than 60 μm, sufficient strength may not be obtained.

Density of the membrane separation activated sludge treatment for semipermeable membrane support of the present invention is preferably 0.30~1.00g / cm ^3, more preferably 0.35~0.98g / cm ^3, 0 More preferably, it is 40 to 0.95 g / cm ³ . When the density is less than 0.30 g / cm ³ , when the separation functional layer is provided on the semipermeable membrane support, the penetration of the coating liquid into the semipermeable membrane support becomes large, and the separation function Layer uniformity may be compromised. On the other hand, when the density is larger than 1.00 g / cm ³ , the frame material melted by the heat fusion treatment or the ultrasonic fusion treatment becomes difficult to bite into the semipermeable membrane support or for the semipermeable membrane. Adhesiveness between the coated surface and non-coated surface of the support may be reduced. Adhesive strength between the semipermeable membrane support and the frame material and adhesion between the coated surface and non-coated surface of the semipermeable membrane support The strength may be weakened. In addition, the permeability of the coating solution may decrease, and the adhesive strength between the semipermeable membrane support and the semipermeable membrane may be weakened.

  The nonwoven fabric related to the support for a semipermeable membrane for membrane separation activated sludge treatment of the present invention can be produced by a dry method or a wet papermaking method. A wet nonwoven fabric formed by a wet papermaking method is preferred.

  In the wet papermaking method, first, stretched polyester fibers (main fibers) and binder fibers are uniformly dispersed in water, and then passed through processes such as screen (removal of foreign matters, lumps, etc.), and the final fiber concentration is 0.01 to The slurry adjusted to 0.50% by mass is made by a paper machine to obtain a wet paper. In order to make the dispersibility of the fibers uniform, chemicals such as dispersants, antifoaming agents, hydrophilic agents, antistatic agents, polymer thickeners, mold release agents, antibacterial agents, bactericides, etc. may be added during the process. is there.

  Examples of the paper machine include a paper machine in which a paper net such as a long net, a circular net, and an inclined wire is installed alone, or a combination paper machine in which two or more types of paper nets of the same type or different types are installed online. Can be used. In addition, when the semipermeable membrane support of the present invention has a multi-layer structure of two or more layers, after forming a laminating method of laminating wet papers produced by each paper machine or forming one layer Any method of casting a slurry in which fibers are dispersed on the layer to form a laminate may be used. When casting the slurry in which the fibers are dispersed, the previously formed layer may be either a wet paper state or a dry state. Two or more layers can be heat-sealed to form a nonwoven fabric having a multilayer structure.

  In the support for a semipermeable membrane for membrane separation activated sludge treatment of the present invention, when the nonwoven fabric has a multilayer structure, it may have a multilayer structure in which the fiber composition of each layer is the same. For the purpose of controlling the permeability of the liquid in the thickness direction within the support body, a multilayer structure in which the fiber composition of each layer is different may be used. In the case of a multilayer structure, since the fiber concentration of the slurry can be lowered by reducing the basis weight of each layer, the formation of the nonwoven fabric is improved, and as a result, the smoothness and uniformity of the coated surface are improved. Moreover, even when the formation of each layer is non-uniform | heterogenous, it can compensate by laminating | stacking. Further, the paper making speed can be increased, and the operability is improved.

  Sheets (base paper) are obtained by drying wet paper produced by a papermaking net with a Yankee dryer, air dryer, cylinder dryer, suction drum dryer, infrared dryer, or the like. When the wet paper is dried, it is brought into close contact with a hot roll such as a Yankee dryer and dried by heat and pressure to improve the smoothness of the contacted surface. Hot-pressure drying means that the wet paper is pressed against the heat roll with a touch roll or the like and dried. The surface temperature of the hot roll is preferably 100 to 180 ° C, more preferably 100 to 160 ° C, and still more preferably 110 to 160 ° C. The pressure is preferably 5 to 100 kN / m, more preferably 10 to 80 kN / m.

  In the present invention, the nonwoven fabric (base paper) is preferably further subjected to a thermal calendar treatment. In the thermal calendering process, calender units having a roll configuration such as metal roll-metal roll, metal roll-elastic roll, metal roll-cotton roll, metal roll-silicon roll can be used alone or in combination. At least one metal roll of the calendar unit is heated. In the present invention, since a sufficient amount of heat can be imparted to the nonwoven fabric and a high strength semipermeable membrane support can be obtained, it is preferable to use a metal roll-elastic roll calender unit.

  The metal roll temperature during the heat calendering is preferably −40 to −10 ° C., more preferably −30 to −20 ° C. with respect to the melting point or softening temperature of the unstretched polyester fiber. When the temperature of the metal roll is lower than −40 ° C. with respect to the melting point or softening temperature of the unstretched polyester fiber, the heat-pressure fusion of the unstretched polyester tends to be insufficient, and the strength of the semipermeable membrane support decreases. There is a case. On the other hand, when the temperature of the metal roll is higher than −10 ° C. with respect to the melting point or softening temperature of the unstretched polyester fiber, the semipermeable membrane support easily adheres to the metal roll, and the semipermeable membrane support The surface may be uneven.

  Further, in the case of a crystalline copolyester having a clear melting point in the sheath portion of the core-sheath polyester composite fiber, the above temperature range is satisfied, and further, the temperature of the metal roll is that of the sheath portion of the core-sheath composite fiber. It is preferably + 50 ° C. or lower with respect to the melting point. When the temperature of the metal roll is higher than + 50 ° C. with respect to the melting point of the sheath portion of the core-sheath polyester composite fiber, the crystallization of the sheath portion is likely to proceed, and the glass transition point is not required. Is likely to be.

  The nip pressure of the nip during the heat calendering is preferably 19 to 180 kN / m, more preferably 39 to 150 kN / m. The processing speed is preferably 5 to 150 m / min, and more preferably 10 to 80 m / min.

  EXAMPLES Hereinafter, the present invention will be specifically described with reference to examples, but the present invention is not limited to the examples. In the examples, all parts and percentages are by mass unless otherwise specified.

<Stretched PET fiber 1>
A stretched polyester fiber made of polyethylene terephthalate and having a fiber diameter of 7 μm and a fiber length of 3 mm was designated as a stretched PET fiber 1.

<Stretched PET fiber 2>
A stretched polyester fiber made of polyethylene terephthalate and having a fiber diameter of 13 μm and a fiber length of 5 mm was designated as stretched PET fiber 2.

<Stretched PET fiber 3>
A stretched polyester fiber made of polyethylene terephthalate and having a fiber diameter of 18 μm and a fiber length of 10 mm was designated as stretched PET fiber 3.

<Stretched PET fiber 4>
A stretched polyester fiber made of polyethylene terephthalate and having a fiber diameter of 25 μm and a fiber length of 10 mm was designated as a stretched PET fiber 4.

<Unstretched PET fiber 1>
Unstretched polyester fiber (melting point: 230 ° C.) made of polyethylene terephthalate and isophthalic acid and having a fiber diameter of 11 μm and a fiber length of 5 mm was designated as unstretched PET fiber 1.

<Unstretched PET fiber 2>
Unstretched polyester fiber (melting point: 260 ° C.) made of polyethylene terephthalate and having a fiber diameter of 11 μm and a fiber length of 5 mm was used as unstretched PET fiber 2.

<Core sheath PET fiber 1>
The core is polyethylene terephthalate (melting point: 260 ° C.), the sheath is amorphous copolymer polyester (glass transition point: 72 ° C.) made of polyethylene terephthalate and isophthalic acid, fiber diameter 15 μm, fiber length 5 mm, core A core-sheath polyester composite fiber having a volume ratio of / sheath part of 50/50 was designated as core-sheath PET fiber 1.

<Core sheath PET fiber 2>
The core is polyethylene terephthalate (melting point: 260 ° C.), the sheath is amorphous copolymer polyester (glass transition point: 72 ° C.) made of polyethylene terephthalate and isophthalic acid, fiber diameter 13 μm, fiber length 5 mm, core A core-sheath polyester composite fiber having a volume ratio of / sheath part of 50/50 was designated as core-sheath PET fiber 2.

<Wet heat adhesive fiber 1>
A single fiber made of polyvinyl alcohol and having a fiber diameter of 10 μm and a fiber length of 3 mm was designated as wet heat adhesive fiber 1.

<Wet heat adhesive fiber 2>
A core-sheath composite fiber having a core component of polyethylene terephthalate, a sheath component of ethylene-vinyl alcohol copolymer, a fiber diameter of 13 μm, a fiber length of 5 mm, and a core / sheath volume ratio of 50/50 is wet-heat adhesive. Fiber 2 was obtained.

<Core-sheath olefin fiber>
The core-sheath composite fiber having a core component of polypropylene and a sheath component of high-density polyethylene, a fiber diameter of 10 μm, a fiber length of 5 mm, and a core / sheath volume ratio of 50/50 was defined as a core-sheath olefin fiber.

  The support bodies for semipermeable membranes for membrane separation activated sludge treatment of Examples 1 to 14 and Comparative Examples 1 to 4 were produced under the following conditions.

(Manufacture of base paper)
After adding water to a 2 m ³ dispersion tank, blended at the raw material blending ratio (%) shown in Table 1, dispersed at a dispersion concentration of 0.2% by weight for 5 minutes, and formed wet paper with a circular net paper machine, Thereafter, it was hot-pressure dried with a Yankee dryer having a surface temperature of 130 ° C., and a wet nonwoven fabric (base papers 1 to 18) having a width of 1000 mm was obtained with the basis weight shown in Table 1 as a target.

(Thermal calendar processing)
The obtained base paper is subjected to a heat calender treatment under the conditions described in Table 2 in a metal roll-elastic roll calender unit, and used for the membrane separation activated sludge treatment of Examples 1 to 14 and Comparative Examples 1 to 4. A semipermeable membrane support was obtained. The surface that hit the metal roll in the first treatment was treated so as to hit the elastic roll in the second treatment, the surface that hit the metal roll in the first treatment was the coated surface, and the metal in the second treatment The surface that contacted the roll was defined as the non-coated surface.

  The following measurements and evaluations were performed on the support for a semipermeable membrane for membrane separation activated sludge treatment obtained in Examples and Comparative Examples, and the results are shown in Tables 3 and 4.

[Basis weight]
The basis weight was measured according to JIS P8124.

[Thickness and density of support for semi-permeable membrane for membrane separation activated sludge treatment]
The thickness of the semipermeable membrane support was measured according to JIS L1086.

[Solvent resistance of semipermeable membrane support]
The semipermeable membrane support was immersed in N-methylpyrrolidone for 10 seconds, washed with pure water, dried in an atmosphere of 23 ° C. and 50% humidity for 24 hours, and the semipermeable membrane support after solvent treatment. The body. About the MD direction and CD direction of the semipermeable membrane support before and after the solvent treatment, using a tabletop material tester (trade name: STA-1150, manufactured by Orientec Co., Ltd.), the grip interval is 100 mm, and the tensile speed is 100 mm / Measure the maximum load when the upper chuck is pulled up until the semipermeable membrane support breaks under the conditions of minutes, and use the sum of the maximum loads in the MD and CD directions as the strength of the semipermeable membrane support. The solvent property was evaluated by the following index.
(Strength of semipermeable membrane support after solvent treatment / strength of semipermeable membrane support before solvent treatment) × 100

A: 80% or more.
B: Less than 80%, 70% or more.
C: Less than 70%.

[Adhesive strength between semipermeable membrane support and frame material]
A support for a semipermeable membrane cut to a width of 30 mm and a length of 50 mm is placed on an ABS resin plate of the same size, and an ultrasonic bonding machine (manufactured by SHENZHEN KEIJING STAR TECHNOLOGY LTD, product name: MSK-800) The head (part number: N1, 4 mm × 4 mm) is applied to the semipermeable membrane support, the output is 40%, the original air pressure is 0.15 MPa, the adhesion time is 1.0 second, and the ABS resin plate and the semipermeable membrane support are not The coated surface was adhered at the ultrasonic fusion point as shown in FIG. Further, the semipermeable membrane support is folded at the folded portion indicated by the dotted line in FIG. 1, and as shown in FIG. 2, the semipermeable membrane support and the ABS resin plate are connected to a tabletop material testing machine (device name: STA). -1150, manufactured by Orientec Co., Ltd.) with a chuck interval of 15 mm, and the upper chuck was pulled up at a constant speed of 100 mm / min until the semipermeable membrane support and the ABS resin plate were peeled off. The maximum load was defined as “adhesive strength between the semipermeable membrane support and the frame material”, and the following indexes were used for evaluation.

A: The adhesive strength of Comparative Example 1 is 1.00, and the strength ratio to Comparative Example 1 is 0.90 or more.
B: Strength ratio to Comparative Example 1 is less than 0.90 and 0.70 or more.
C: The strength ratio to Comparative Example 1 is less than 0.70.

[Adhesive strength between coated and non-coated surfaces of semipermeable membrane support]
Two semipermeable membrane supports having a width of 30 mm and a length of 50 mm are prepared, the tip of one semipermeable membrane support is 10 mm, and the other end of the semipermeable membrane support is The 10 mm portion is superposed so that the coated surface of one semipermeable membrane support and the non-coated surface of the other semipermeable membrane support are in contact with each other, and an ultrasonic bonding machine (SHENZHEN KEIJING STAR TECHNOLOGY LTD Manufactured using product name: MSK-800, head product number: N1 (4 mm × 4 mm)), output of 5%, original air pressure of 0.10 MPa, adhesion time of 1.0 sec. The coated surface and the non-coated surface were bonded at the ultrasonic fusion point as shown in FIG. Further, as shown in FIG. 4, two semipermeable membrane supports are fixed to a chuck of a tabletop material testing machine (device name: STA-1150, manufactured by Orientec Co., Ltd.) with a chuck interval of 15 mm. The maximum load when the upper chuck is pulled up until the two semipermeable membrane supports are peeled off at a constant speed of 100 mm / min is “the adhesive strength between the coated surface and the non-coated surface of the semipermeable membrane support”. And evaluated by the following indicators.

A: The adhesive strength of Comparative Example 1 is 1.00, and the strength ratio to Comparative Example 1 is 0.90 or more.
B: Strength ratio to Comparative Example 1 is less than 0.90 and 0.70 or more.
C: The strength ratio to Comparative Example 1 is less than 0.70.

[Semipermeable membrane adhesion of semipermeable membrane support]
Using a constant speed coating apparatus (trade name: TQC fully automatic film applicator, Cortec Co., Ltd.) having a certain clearance, polyvinylidene fluoride colored with magic ink (registered trademark) on the support surface of the semipermeable membrane support ( A PVDF) N-methylpyrrolidone solution (concentration: 12%) was applied, washed with water, and dried to form a PVDF film on the coated surface of the support for semipermeable membrane, thereby producing a semipermeable membrane.

  One day after preparation of the semipermeable membrane, the sample is cut into a width of 24 mm (cross direction with respect to the application direction) × length of 50 mm (application direction). A cellophane pressure-sensitive adhesive tape (manufactured by Nichiban Co., Ltd., trade name: Elpac (registered trademark) LP24) cut to a width of 24 mm and a length of 30 mm is pasted on the non-coated surface of the cut semipermeable membrane support, only a 10 mm length portion. The remaining 24 mm width and 20 mm length part is left as an adhesive part. Next, the adhesive part of the adhesive memo (product name: stick-on-note SN-23, manufactured by Lion Corporation) is pasted on the 24 mm wide × 10 mm long part of the semipermeable membrane surface. It has an adhesive part (24mm x 20mm) of cellophane adhesive tape and a non-adhesive part of an adhesive memo, and it is pulled by hand in the direction where the semipermeable membrane and the semipermeable membrane support peel, and depending on the state when the force is applied The semipermeable membrane adhesion was judged. Five samples were prepared and tested five times.

  When cellophane adhesive tape is applied to the semipermeable membrane surface and the non-coated surface and both cellophane adhesive tapes are pulled, in most cases, peeling occurs between the semipermeable membrane and the semipermeable membrane support. It was difficult to evaluate the permeability of the permeable membrane. The adhesiveness between the semipermeable membrane and the semipermeable membrane support can be determined by using an adhesive memo having a lower adhesiveness than the cellophane adhesive tape and confirming where the peeling has occurred. The “adhesiveness between the semipermeable membrane support and the semipermeable membrane” was evaluated according to the following criteria.

Judgment criteria A: Peeling occurred between the semipermeable membrane and the adhesive memo in all five tests. Very good level.
B: Peeling occurred between the semipermeable membrane and the adhesive memo in 3 to 4 tests. Good level.
C: Peeling occurred between the semipermeable membrane and the adhesive memo in one or two tests. Practically lower limit level.
D: Peeling occurred between the semipermeable membrane and the semipermeable membrane support in all five tests. Unusable level.

[Adhesion between fused part and semipermeable membrane]
Two semipermeable membrane supports with a width of 130 mm and a length of 180 mm are superposed so that the coated surface and the non-coated surface are in contact with each other, and an ultrasonic bonding machine (SHENZHEN KEIJING STAR TECHNOLOGY LTD, manufactured by Name: MSK-800, head part number: N1 (4 mm × 4 mm)), output 5%, original air pressure 0.1 MPa, adhesion time 1.0 sec. And the non-coated surface were bonded at the ultrasonic fusion point as shown in FIG. The width of the ultrasonic fusion point was 12 mm and the length was 50 mm.

  Next, an N-methylpyrrolidone solution of PVDF (concentration: 12%) colored with magic ink (registered trademark) using a constant speed coating apparatus (trade name: TQC fully automatic film applicator, Cortec Co., Ltd.) having a certain clearance. ), Washed with water, and dried to form a PVDF film on the coated surface of the semipermeable membrane support including the ultrasonic fusion point, thereby producing a semipermeable membrane.

  One day after the production, an ultrasonic fusion point (fused part, width 12 mm, length 50 mm) is cut out and used as a sample. A cellophane adhesive tape (product name: Elpac (registered trademark) LP12, manufactured by Nichiban Co., Ltd.) cut to a width of 12 mm and a length of 30 mm is pasted on the non-coated surface of the sample, and the remaining width of 12 mm and length is applied. The 20 mm part is left as an adhesive part. Next, an adhesive part of an adhesive memo (manufactured by Lion Corporation, product name: Stick-on-note SN-23) is affixed to a part having a width of 12 mm and a length of 10 mm on the semipermeable membrane surface. It has an adhesive part (12mm x 20mm) of cellophane adhesive tape and a non-adhesive part of an adhesive memo, and is pulled by hand in the direction in which the semipermeable membrane and the semipermeable membrane support peel off, depending on the state when the force is applied The semipermeable membrane adhesion was judged. Five samples were prepared and tested five times. The “adhesiveness between the fused portion and the semipermeable membrane” was evaluated according to the following criteria.

Judgment criteria A: Peeling occurred between the semipermeable membrane and the adhesive memo in all five tests. Very good level. B: Peeling occurred between the semipermeable membrane and the adhesive memo in 3 to 4 tests. Good level.
C: Peeling occurred between the semipermeable membrane and the adhesive memo in one or two tests. Practically lower limit level. D: Peeling occurred between the semipermeable membrane and the semipermeable membrane support in all five tests. Unusable level.

[Semipermeable membrane applicability evaluation of semipermeable membrane support]
For the semipermeable membrane produced in “Semipermeable membrane adhesion evaluation of semipermeable membrane support”, the surface of the semipermeable membrane support, which is present in a 10 cm wide and 10 cm long square, is fluffed. The number of damaged portions (damaged portions) of the semipermeable membrane was observed with a magnifying glass having a magnification of 10 times, and “semipermeable membrane coatability of the semipermeable membrane support” was evaluated according to the following evaluation criteria.

Evaluation criteria A: The number of damaged parts is 3 or less, good level B: The number of damaged parts is 5 or less, and the practical level C: The number of damaged parts is more than 5 and the level is not practical .

[Wrinkle evaluation of semipermeable membrane support]
The wrinkles in the flow direction observed on the semipermeable membrane support were evaluated according to the following criteria.
A: Wrinkles are not observed on the heat calender roll, and wrinkles are not observed on the support for the semipermeable membrane after the heat calender treatment, which is a very good level.
B: On the heat calender roll, some wrinkles are observed in the flow direction of the support for the semipermeable membrane, but no wrinkles are observed on the support for the semipermeable membrane after the heat calendar treatment, and there is no practical problem.
C: Wrinkles are observed in the flow direction of the semipermeable membrane support on the heat calender roll, and wrinkles are also observed on the semipermeable membrane support after the heat calendering treatment.

  As shown in Table 4, the support for a semipermeable membrane for membrane separation activated sludge treatment of Examples 1 to 14 has stretched polyester fibers, unstretched polyester fibers as binder fibers, and a copolymer polyester as a sheath. Since it is a non-woven fabric comprising a core-sheath polyester composite fiber and a wet heat adhesive fiber, it has excellent solvent resistance, adhesive strength between the semipermeable membrane support and the frame material, and the semipermeable membrane support The adhesive strength between the coated surface and the non-coated surface was strong, and the adhesiveness with the semipermeable membrane and the adhesiveness between the fused portion and the semipermeable membrane were good.

  From the comparison between Example 1 and Example 9, the support for a semipermeable membrane of Example 1 in which the binder fiber content is 20% by mass or more is an example in which the binder fiber content is less than 20% by mass. The number of parts (damaged portions) where the semipermeable membrane was damaged by fuzz on the surface of the semipermeable membrane support was smaller than that of the semipermeable membrane support of No. 9, and the coating properties of the semipermeable membrane were excellent.

  Moreover, from the comparison between Example 2 and Example 10, the support for the semipermeable membrane of Example 2 in which the content of the binder fiber is 50% by mass or less, the content of the binder fiber exceeds 50% by mass. The adhesive strength between the semipermeable membrane support and the frame material is superior to the semipermeable membrane support of Example 10, and the adhesiveness between the semipermeable membrane support and the semipermeable membrane, and the fused portion and the semipermeable membrane. The adhesiveness was also good.

  From a comparison between Example 3 and Example 11, the support for a semipermeable membrane of Example 3 in which the content of unstretched polyester fiber is 5% by mass or more has a content of unstretched polyester fiber of less than 5% by mass. A better result was obtained in the wrinkle evaluation of the support for semipermeable membrane than the support for semipermeable membrane of Example 11 which is.

  From the comparison between Example 4 and Example 12, the support for the semipermeable membrane of Example 4 in which the content of unstretched polyester fiber is 30% by mass or less has the content of unstretched polyester fiber of 30% by mass. More than% of the support for semipermeable membrane of Example 12, the adhesive strength between the support for semipermeable membrane and the frame material was excellent, and the adhesion between the fused portion and the semipermeable membrane was also good.

  From the comparison between Example 5 and Example 13, the support for a semipermeable membrane of Example 5 in which the content of wet heat adhesive fiber is 1% by mass or more has a content of wet heat adhesive fiber of less than 1% by mass. It was superior to the semipermeable membrane support of Example 13 in that the solvent resistance was excellent.

  Moreover, from the comparison between Example 6 and Example 14, the support for the semipermeable membrane of Example 6 in which the content of the wet heat adhesive fiber is 5% by mass or less has the content of the wet heat adhesive fiber of 5% by mass. % Better than the semipermeable membrane support of Example 14 and better in the adhesive strength between the semipermeable membrane support and the frame material and between the coated surface and the non-coated surface of the semipermeable membrane support, The adhesion between the permeable membrane support and the semipermeable membrane and the adhesion between the fused portion and the semipermeable membrane were also good.

  As the binder fiber, the support for semipermeable membrane of Comparative Example 1 which does not contain wet heat adhesive fiber and contains unstretched polyester fiber and core-sheath type polyester composite fiber is the same as the support for semipermeable membrane of Example. In comparison, the solvent resistance was very poor.

  As the binder fiber, the semipermeable membrane support of Comparative Example 2 containing no core-sheath polyester composite fiber and containing unstretched polyester fiber and wet heat adhesive fiber is the same as the semipermeable membrane support of Example. In comparison, the adhesion strength between the semipermeable membrane support and the frame material and the adhesion strength between the coated surface and the non-coated surface of the semipermeable membrane support were very poor.

  The support for a semipermeable membrane of Comparative Example 3 which does not contain unstretched polyester fiber as the binder fiber and contains the core-sheath type polyester composite fiber and the wet heat adhesive fiber has a lot of wrinkles during the heat calender treatment. The coating solution is difficult to enter the semipermeable membrane support during the semipermeable membrane coating, and the adhesion between the semipermeable membrane support and the semipermeable membrane and the adhesion between the fused portion and the semipermeable membrane are very poor. As a result.

  The semipermeable membrane support of Comparative Example 4 composed of the core-sheath olefin composite fiber and the wet heat adhesive fiber is different from the semipermeable membrane support of the example in comparison with the semipermeable membrane support and the frame material. The adhesive strength of the film was very poor, and the adhesion between the semipermeable membrane support and the semipermeable membrane and the adhesion between the fused portion and the semipermeable membrane were also very poor.

  The support for semipermeable membranes for membrane separation activated sludge treatment of Examples 15 to 28 and Comparative Examples 5 to 8 was produced under the following conditions.

(Manufacture of base paper)
After charging water into a 2 m ³ dispersion tank, blended at the raw material blending ratio (%) shown in Table 5, dispersed for 5 minutes at a dispersion concentration of 0.2% by weight, and using a slanted / circular mesh paper machine, After laminating both wet papers formed on the inclined wire and the circular wire before drying, they are hot-pressure dried with a Yankee dryer having a surface temperature of 130 ° C., and the basis weight shown in Table 5 is targeted. A 1000 mm wet nonwoven fabric (base paper 19 to 36) was obtained.

(Thermal calendar processing)
The obtained base papers 19 to 36 were subjected to thermal calender treatment under the conditions described in Table 6 in a metal roll-elastic roll calender unit, and membrane separation activities of Examples 15 to 28 and Comparative Examples 5 to 8 were performed. A support for a semipermeable membrane for sludge treatment was obtained. The inclined layer surface hits the metal roll in the first treatment, and the circular mesh layer surface hits the metal roll in the second treatment, and the inclined layer surface was the coated surface and the circular mesh layer surface was the non-coated surface. .

  The following measurements and evaluations were performed on the membrane-permeable activated sludge treatment semipermeable membrane supports obtained in Examples 15 to 28 and Comparative Examples 5 to 8, and the results are shown in Tables 7 and 8.

[Basis weight of support for semipermeable membrane for membrane separation activated sludge treatment]
The basis weight was measured in the same manner as in Examples 1 to 14 and Comparative Examples 1 to 4.

[Thickness and density of support for semi-permeable membrane for membrane separation activated sludge treatment]
Thickness was measured by the method similar to Examples 1-14 and Comparative Examples 1-4.

[Solvent resistance of semipermeable membrane support]
Measurement was performed in the same manner as in Examples 1 to 14 and Comparative Examples 1 to 4, and “solvent resistance of the semipermeable membrane support” was evaluated using the same index.

[Adhesive strength between semipermeable membrane support and frame material]
A semipermeable membrane support cut to a width of 30 mm and a length of 50 mm was placed on an ABS resin plate of the same size so that the surface of the circular mesh layer was in contact, and the same as in Examples 1 to 14 and Comparative Examples 1 to 4 The measurement was performed by the method, and “adhesive strength between the semipermeable membrane support and the frame material” was evaluated using the same index.

[Adhesive strength between coated and non-coated surfaces of semipermeable membrane support]
Two semipermeable membrane supports having a width of 30 mm and a length of 50 mm are prepared, the tip of one semipermeable membrane support is 10 mm, and the other end of the semipermeable membrane support is 10 mm and 10 mm, and the inclined layer surface of one semipermeable membrane support and the circular mesh layer surface of the other semipermeable membrane support are overlapped with each other. Measurement was performed in the same manner as in No. 4, and “adhesive strength between the coated surface and the non-coated surface of the semipermeable membrane support” was evaluated using the same index.

[Semipermeable membrane adhesion evaluation of semipermeable membrane support]
Using the inclined layer surface as the coating surface, the test was performed in the same manner as in Examples 1 to 14 and Comparative Examples 1 to 4, and “adhesiveness between the semipermeable membrane support and the semipermeable membrane” was determined according to the same criteria. Evaluated.

[Evaluation of adhesion between inclined fused part and semipermeable membrane]
Using the inclined layer surface as the coating surface, tests were performed in the same manner as in Examples 1 to 14 and Comparative Examples 1 to 4, and “adhesion between the fused portion and the semipermeable membrane” was evaluated according to the same criteria. .

[Semipermeable membrane applicability evaluation of semipermeable membrane support]
Using the inclined layer surface as the coating surface, tests were performed in the same manner as in Examples 1 to 14 and Comparative Examples 1 to 4, and “semipermeable membrane coating property of semipermeable membrane support” was evaluated according to the same criteria. did.

[Wrinkle evaluation of semipermeable membrane support]
“Wrinkles of semipermeable membrane support” were evaluated according to the same criteria as in Examples 1 to 14 and Comparative Examples 1 to 4.

  As shown in Table 8, the support for a semipermeable membrane for membrane separation activated sludge treatment of Examples 15 to 28 is a core sheath having a stretched polyester fiber, an unstretched polyester fiber as a binder fiber, and a copolymer polyester as a sheath. Type polyester composite fiber and wet heat-adhesive fiber, so it has excellent solvent resistance, adhesion strength between semipermeable membrane support and frame material, and application of semipermeable membrane support The adhesive strength between the surface and the non-coated surface was strong, and the adhesion between the semipermeable membrane support and the semipermeable membrane and the adhesion between the fused portion and the semipermeable membrane were good.

  From a comparison between Example 15 and Example 23, the support for a semipermeable membrane of Example 15 in which the binder fiber content is 20% by mass or more is an example in which the binder fiber content is less than 20% by mass. The number of portions (damaged portions) where the semipermeable membrane was damaged by fuzz on the surface of the semipermeable membrane support was smaller than that of the semipermeable membrane support of No. 23, and the semipermeable membrane coatability was excellent.

  Moreover, from the comparison between Example 16 and Example 24, the support for a semipermeable membrane of Example 16 in which the content of the binder fiber is 50% by mass or less, the content of the binder fiber exceeds 50% by mass. The adhesive strength between the semipermeable membrane support and the frame material is superior to the semipermeable membrane support of Example 24, and the adhesion between the semipermeable membrane support and the semipermeable membrane, and the fused portion and the semipermeable membrane. The adhesiveness was also good.

  From a comparison between Example 17 and Example 25, the support for a semipermeable membrane of Example 17 in which the content of unstretched polyester fiber is 5% by mass or more has a content of unstretched polyester fiber of less than 5% by mass. A better result was obtained in the wrinkle evaluation of the semipermeable membrane support than the semipermeable membrane support of Example 25.

  Further, from the comparison between Example 18 and Example 26, the support for a semipermeable membrane of Example 18 in which the content of unstretched polyester fiber is 30% by mass or less has a content of unstretched polyester fiber of 30% by mass. More than% of the semipermeable membrane support of Example 26, the adhesive strength between the semipermeable membrane support and the frame material was excellent, and the adhesion between the fused portion and the semipermeable membrane was also good.

  From the comparison between Example 19 and Example 27, the support for a semipermeable membrane of Example 19 in which the content of the wet heat adhesive fiber is 1% by mass or more has a content of the wet heat adhesive fiber of less than 1% by mass. It was superior to the semipermeable membrane support of Example 27 in that the solvent resistance was excellent.

  From the comparison between Example 20 and Example 28, the support for the semipermeable membrane of Example 20 in which the content of wet heat adhesive fiber is 5% by mass or less has the content of wet heat adhesive fiber of 5% by mass. % Better than the semipermeable membrane support of Example 28 and better in the adhesion strength between the semipermeable membrane support and the frame material and between the coated surface and the non-coated surface of the semipermeable membrane support, The adhesion between the permeable membrane support and the semipermeable membrane and the adhesion between the fused portion and the semipermeable membrane were also good.

  As the binder fiber, the support for a semipermeable membrane of Comparative Example 5 containing no wet heat adhesive fiber and containing an unstretched polyester fiber and a core-sheath polyester composite fiber is the same as the support for a semipermeable membrane of the example. In comparison, the solvent resistance was very poor.

  As the binder fiber, the semipermeable membrane support of Comparative Example 6 containing no core-sheath type polyester composite fiber and containing unstretched polyester fiber and wet heat adhesive fiber is the same as the semipermeable membrane support of Example. In comparison, the adhesion strength between the semipermeable membrane support and the frame material and the adhesion strength between the coated surface and the non-coated surface of the semipermeable membrane support were very poor.

  As a binder fiber, the support for a semipermeable membrane of Comparative Example 7, which does not contain an unstretched polyester fiber and contains a core-sheath polyester composite fiber and a wet heat adhesive fiber, is often wrinkled during thermal calendering, The adhesion between the semipermeable membrane support and the semipermeable membrane and the adhesion between the fused portion and the semipermeable membrane were very poor.

  The semipermeable membrane support of Comparative Example 8 composed of the core-sheath olefin composite fiber and the wet heat adhesive fiber is different from the semipermeable membrane support of the example in comparison with the semipermeable membrane support and the frame material. The adhesive strength of the film was very poor, and the adhesion between the semipermeable membrane support and the semipermeable membrane and the adhesion between the fused portion and the semipermeable membrane were also very poor.

  The support for a semipermeable membrane for membrane separation activated sludge treatment of the present invention can be used in the field of sewage treatment by a membrane separation activated sludge treatment method.

Claims (7)

  In the semipermeable membrane support for membrane separation activated sludge treatment, the semipermeable membrane support is a core-sheath type polyester composite having a stretched polyester fiber, an unstretched polyester fiber as a binder fiber, and a copolymer polyester as a sheath. A support for a semipermeable membrane for membrane separation activated sludge treatment comprising fibers and wet heat adhesive fibers.   The support for a semipermeable membrane for membrane separation activated sludge treatment according to claim 1, wherein the wet heat adhesive fiber is at least one selected from the group of vinyl alcohol fibers and ethylene-vinyl alcohol fibers.   The content of the binder fiber is 20 to 50% by mass and the content of the wet heat adhesive fiber is 1 to 5% by mass with respect to the entire fiber contained in the semipermeable membrane support. A support for semipermeable membrane for membrane separation activated sludge treatment.   The content of unstretched polyester fiber is 5 to 30% by mass with respect to the entire fiber contained in the support for semipermeable membrane. The semipermeable membrane for membrane separation activated sludge treatment according to any one of claims 1 to 3 Support.   A filtration membrane for membrane separation activated sludge treatment, comprising a semipermeable membrane support provided on the support for membrane separation activated sludge treatment semipermeable membrane according to any one of claims 1 to 4.   6. A module comprising the membrane separation activated sludge filtration membrane according to claim 5.   The module according to claim 6, wherein the module is at least one selected from the group consisting of a flat membrane module, a tubular module, and a tubular module.