JP2017144420A - Semi-permeable membrane support for membrane separation activated sludge treatment, membrane filter and module - Google Patents

Abstract

PROBLEM TO BE SOLVED: To realize a semi-permeable membrane support for a membrane separation activated sludge treatment which is excellent in strength, adhesive strength with a frame material and adhesive strength between a coated surface of the semi-permeable membrane support and a non-coated surface thereof, and adhesive property with the semi-permeable membrane, and to provide a membrane filter for a membrane separation activated sludge treatment which is resistant to shock, excellent in adhesive property with the frame material, and adhesive property between a fusion-spliced portion of the semi-permeable membrane support and the semi-permeable membrane, and a module using the membrane filter.SOLUTION: A semi-permeable membrane support for a membrane separation activated sludge treatment consists of nonwoven fabric containing drawing polyester fiber and binder fiber as main components. The nonwoven fabric contains: non-drawing polyester fiber as binder fiber; and core-in-sheath polyester compound fiber including copolymer polyester as a sheath part. The nonwoven fabric is a multilayer nonwoven fabric comprising: a first surface lamination containing the non-drawing polyester fiber as the binder fiber and the core-in-sheath polyester compound fiber; and a second surface lamination containing only the non-drawing polyester fiber as the binder fiber.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 are easily peeled off. There is a problem that the permeable membrane 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, a semipermeable membrane support (for example, see Patent Document 1) obtained by heat-treating a composite fiber using polypropylene as a core material and polyethylene as a sheath material, or a semipermeable membrane having a nonwoven fabric layer formed from a single polypropylene fiber on the surface Supports (for example, see Patent Document 2) and the like have been proposed. When a filtration membrane provided with a semipermeable membrane on a semipermeable membrane support containing olefin fibers is bonded to the frame material by ultrasonic fusion treatment, it adheres, but the semipermeable membrane support and the frame material Adhesiveness 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.

JP 2001-17842 A JP-A-56-152705 JP 2010-194478 A JP 2012-101213 A JP 2013-220382 A

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>

  The object of the present invention is a membrane separation activity that has high strength, excellent adhesion strength to the frame material, excellent adhesion strength between the coated surface and non-coated surface of the support for semipermeable membrane, and excellent adhesion to the semipermeable membrane Realizes a support for semipermeable membrane for sludge treatment, is strong against impact, has good adhesion to the frame material, and has good adhesion between the fused part of the support for semipermeable membrane and the semipermeable membrane A separation membrane for treating activated sludge and a module using the filtration membrane are provided.

  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 first surface layer containing unstretched polyester fibers and core-sheath polyester composite fibers as binder fibers, and a second surface layer containing only unstretched polyester fibers as binder fibers. A support for a semipermeable membrane for membrane-separated activated sludge treatment, which is a multilayer nonwoven fabric.

(2) The support for a semipermeable membrane for membrane separation activated sludge treatment according to the above (1), wherein the sheath of the core-sheath polyester composite fiber is a copolyester having a glass transition point of 40 to 80 ° C.

(3) In 1st surface layer, content of binder fiber is 20-60 mass% with respect to the whole fiber contained in 1st surface layer, and content of core-sheath-type polyester composite fiber is 5-40 mass%. The support for a semipermeable membrane for membrane separation activated sludge treatment according to the above (1) or (2).

(4) In the second surface layer, the membrane separation according to any one of the above (1) to (3), wherein the content of the binder fiber is 20 to 60% by mass with respect to the entire fibers contained in the second surface layer. Support for semipermeable membrane for activated sludge treatment.

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

(6) A module comprising the membrane for activated membrane sludge described in (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 has high strength, adhesion strength with the frame material, and adhesion strength between the coated surface and the non-coated surface of the semipermeable membrane support (that is, the first Excellent adhesion strength between the surface layer and the second surface layer), and excellent adhesion strength with the semipermeable membrane. By using the support for semipermeable membrane for membrane separation activated sludge treatment of the present invention, it is strong against impact. A membrane separation activated sludge treatment filtration membrane having good adhesion to the frame material holding the semipermeable membrane and good adhesion between the fused portion of the semipermeable membrane support and the semipermeable membrane, and the filtration It is possible to provide a module using a membrane.

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. In the evaluation of the support for a semipermeable membrane for membrane separation activated sludge treatment, a method for bonding the first surface layer and the second surface layer to measure the adhesive strength between the first surface layer and the second surface layer was shown. FIG. It is the schematic which showed the method of measuring the adhesive strength of a 1st surface layer and a 2nd surface layer in evaluation of the support body for semi-permeable membranes for membrane separation activated sludge processes. In the evaluation of the support for a semipermeable membrane for membrane separation activated sludge treatment, an outline showing a method for measuring the adhesive strength of the semipermeable membrane provided in the portion where the first surface layer and the second surface layer are fused. FIG.

  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 contains a stretched polyester fiber, an unstretched polyester fiber as a binder fiber, and a core-sheath type polyester composite fiber having a copolymer polyester as a sheath, It is a multilayer nonwoven fabric having a first surface layer containing unstretched polyester fibers and core-sheath polyester composite fibers as binder fibers, and a second surface layer containing only unstretched polyester fibers as binder fibers. To do.

  The support for a semipermeable membrane for membrane separation activated sludge treatment of the present invention contains only unstretched polyester fibers as binder fibers in the second surface layer as the coating surface, and binder fibers in the first surface layer as the non-coating surface. As an unstretched polyester fiber and a core-sheath type polyester composite fiber, the adhesive strength between the support for a semipermeable membrane and the frame material and the adhesive strength between the first surface layer and the second surface layer is excellent. The effect that it is excellent also in the adhesive strength of the support body for membranes and a semipermeable membrane is acquired. In the case of a flat membrane module, the second surface layer is the application surface, and the first surface layer is the frame material bonding surface. In the tubular semipermeable membrane support in the tubular / tubular module, when the semipermeable membrane is provided outside the tubular semipermeable membrane support, the tape-shaped semipermeable membrane is disposed so that the second surface layer is outside. When the membrane support is spirally wound and, conversely, when a semipermeable membrane is provided inside the tubular semipermeable membrane support, the tape-shaped semipermeable membrane support is placed so that the second surface layer is inside. Wrap the body in a spiral. The support for a semipermeable membrane for membrane separation activated sludge treatment of the present invention may be a two-layer nonwoven fabric composed of a first surface layer and a second surface layer, or a first surface layer and a second surface layer. It may be a multilayer nonwoven fabric of three or more layers having another layer therebetween.

  In the present invention, as the unstretched polyester fiber used as the binder fiber, a polyester such as polyethylene terephthalate, polytrimethylene terephthalate, polybutylene terephthalate, polyethylene naphthalate, polybutylene naphthalate and a copolymer mainly composed thereof is spun. Examples thereof include undrawn fibers spun at a speed of 800 to 1,200 m / min. 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 sheath portion of the core-sheath polyester composite fiber used as the binder fiber is a copolymer polyester, and is preferably a copolymer polyester having a glass transition point of 40 to 80 ° C. Copolyester includes a terephthalic acid component and an ethylene glycol component, and an isophthalic acid component, adipic acid component, sebacic acid component, naphthalenedicarboxylic acid component, diethyl glycol component, 1,4-butanediol component and aliphatic 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 general, the binder fiber improves the mechanical strength of the semipermeable membrane support by incorporating the process of raising the temperature until the binder fiber is softened or melted into the method for producing the semipermeable membrane support. Therefore, regarding melting | fusing point of the sheath part of a core sheath type polyester composite fiber, patent document 4 (Unexamined-Japanese-Patent No. 2012-101213) and patent document 5 (Unexamined-Japanese-Patent No. 2013-220382) are also examined, for example. The present inventor studied for the purpose of increasing the adhesive strength between the support for a semipermeable membrane and the frame material and the adhesive strength between the first surface layer and the second surface layer, and the glass transition point was 40 to 80 ° C. When the copolyester is used as the sheath, the adhesion between the semipermeable membrane support and the frame material and the first surface layer of the semipermeable membrane support when heat fusion treatment or ultrasonic fusion treatment is performed. Excellent adhesion between the second surface layer and the adhesive strength between the semipermeable membrane support and the frame material and the adhesive strength between the first surface layer and the second surface layer of the semipermeable membrane support. And it discovered that it was effective not only in heat fusion processing but also in ultrasonic fusion processing.

  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 first surface layer and the second surface layer are increased. On the other hand, when the glass transition point is 80 ° C. or lower, the adhesion between the support for the semipermeable membrane and the frame material or the first surface layer and the second surface layer when the heat fusion treatment or the ultrasonic fusion treatment is performed. As 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 adhesive strength between the first surface layer and the second surface layer Will improve.

  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 the first surface layer, the content of the binder fiber is preferably 20 to 60% by mass, and more preferably 25 to 50% by mass with respect to the entire fibers contained in the first surface layer. When the content of the binder fiber is less than 20% by mass, the adhesion between the fibers of the first surface layer tends to be insufficient, and the adhesive strength between the semipermeable membrane support and the frame material is reduced, or the first surface layer And the adhesive strength between the second surface layer may decrease. On the other hand, if the binder fiber content exceeds 60% by mass, the surface of the first surface layer tends to be formed into a film by sticking to the heated metal roll in the thermal calendering process, so that the heat fusion treatment or ultrasonic fusion is performed. When the frame material melted by the treatment or the like becomes difficult to bite into the semipermeable membrane support, the adhesive strength between the semipermeable membrane support and the frame material may be lowered. Further, in the tubular semipermeable membrane support, the fusion part between the first surface layer and the second surface layer is easily formed into a film, and the semipermeable membrane is less likely to bite into the fusion part. And the adhesive strength between the semipermeable membrane and the semipermeable membrane may be reduced.

  The first surface layer, which is a non-coated surface, contains a core-sheath type polyester composite fiber, so that the frame material and the semi-transparent layer can be used in the heat-sealing process and the ultrasonic fusing process during the production of the flat membrane module. Adhesion with the membrane support is improved, and a semipermeable membrane support with high adhesion strength to the frame material can be obtained. Also, when manufacturing a tubular semipermeable membrane support in a tubular / tubular module, the adhesion between the first surface layer and the second surface layer is improved, and the adhesion between the first surface layer and the second surface layer is improved. A semipermeable membrane support having high strength can be obtained.

  The content of the core-sheath type polyester composite fiber of the first surface layer is 5 to 40% by mass, more preferably 7 to 35% by mass, and more preferably 10 to 30% by mass with respect to the entire fibers contained in the first surface layer. More preferably. When the content of the core-sheath type polyester composite fiber is less than 5% by mass, the adhesion between the semipermeable membrane support and the frame material and the adhesion between the first surface layer and the second surface layer may be insufficient. In some cases, the adhesive strength between the semipermeable membrane support and the frame material and the adhesive strength between the first surface layer and the second surface layer may be reduced. On the other hand, when the content of the core-sheath polyester composite fiber exceeds 40% by mass, the content of the unstretched polyester fiber is relatively reduced. The fibers present on the surface layer are likely to fluff, and the adhesive strength between the semipermeable membrane support and the frame material may be reduced.

  In the second surface layer, the content of unstretched polyester fibers contained as binder fibers is preferably 20 to 60% by mass, and preferably 25 to 50% by mass with respect to the entire fibers contained in the second surface layer. Is more preferable. If the content of the binder fiber is less than 20% by mass, the adhesion between the fibers tends to be insufficient, the fibers on the surface of the second surface layer tend to fluff, and the coating property of the semipermeable membrane may be impaired. On the other hand, when the content of the binder fiber exceeds 60% by mass, the surface of the second surface layer and the fused portion between the first surface layer and the second surface layer are easily formed into a film, and the permeability of the coating liquid is reduced. Thus, 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 25 μm, more preferably 5 to 20 μm, and still more preferably 10 to 20 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 25 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 semipermeable membrane is improved. It may be damaged.

  In the present invention, the fiber length of the binder fiber is preferably 1 to 12 mm, more preferably 3 to 10 mm, and still more preferably 4 to 6 mm. When the fiber length is less than 1 mm, the strength of the semipermeable membrane support may decrease. When the fiber length exceeds 12 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.

  The support for a semipermeable membrane for membrane separation activated sludge treatment of the present invention contains a stretched polyester fiber as a main fiber. In the present invention, the binder fiber improves the mechanical strength of the semipermeable membrane support by incorporating the process of raising the temperature until the binder fiber is softened or melted into the method for producing the semipermeable membrane support. In the step of raising the temperature, the stretched polyester fiber is difficult to soften or melt, and the cross-sectional shape may change, but the shape as a fiber is not impaired, and the skeleton of the support for a semipermeable membrane is used as a main fiber. Form. 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 for preventing back-through and smoothing the coated surface.

  The fiber diameter of the stretched polyester fiber is preferably 2 to 35 μm, more preferably 5 to 30 μm, and still more preferably 7 to 27 μm. When the fiber diameter of the stretched polyester fiber is less than 2 μm, the strength of the semipermeable membrane support may be insufficient. On the other hand, when the fiber diameter of the stretched polyester fiber exceeds 35 μm, the 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 semipermeable membrane 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 synthetic fibers include polyolefin fibers, polyamide fibers, polyacrylic resins, vinylon resins, vinylidene, polyvinyl chloride, benzoate, polyclar, and phenol 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-mentioned fibers, wood fibers such as conifer pulp and hardwood pulp, woods such as bamboo pulp, bamboo pulp, 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. Further, not only fibers having a circular cross-sectional shape but also fibers having an irregular cross section such as T-type, Y-type, and triangle can be contained.

  The glass transition point of the sheath part of the core-sheath type polyester composite fiber in the present invention was measured at a heating rate of 10 ° C./min using a differential scanning calorimeter (manufactured by Perkin Elmer, apparatus name: DSC8500). 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, 50~220g / 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 80 to 250 μm, and still more preferably 100 to 220 μm. When the thickness exceeds 300 μm, the area of the filtration membrane that can be incorporated into the unit is reduced, and as a result, the life of the filtration 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 / cm ³ . When the density is less than 0.30 g / cm ³ , when the semipermeable membrane is provided on the semipermeable membrane support, the penetration of the coating liquid into the semipermeable membrane support becomes large, and the separation function There is a case where the uniformity of the film is impaired. On the other hand, when the density is larger than 1.00 g / cm ³ , the case where the melted frame material is difficult to bite into the semipermeable membrane support by heat fusion treatment or ultrasonic fusion treatment or the first surface The adhesion between the layer and the second surface layer may be reduced, and the adhesive strength between the semipermeable membrane support and the frame material and the adhesive strength between the first surface layer and the second surface layer 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.

  As the paper machine, for example, a paper machine in which a paper net such as a long net, a circular net, or an inclined wire is installed alone, or a combination in which two or more of the same or different types of these paper nets are installed online. It can be manufactured by a paper machine. The support for a semipermeable membrane for membrane separation activated sludge treatment of the present invention is a multilayer nonwoven fabric, and as a manufacturing method thereof, for example, a combination method of laminating wet papers made by each papermaking net, Examples thereof include a casting method in which a slurry in which fibers are dispersed is cast on the formed layer, and another layer is formed and laminated. In the casting method, the previously formed layer may be in a wet paper state or in a dry state. In addition, two or more dry layers can be heat-sealed to form a multilayer nonwoven fabric.

  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.

  The nip pressure (linear pressure) of the nip during the heat calendar process 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 stretched PET fiber 4.

<Stretched PET fiber 5>
A drawn polyester fiber 5 made of polyethylene terephthalate and having a fiber diameter of 30 μm and a fiber length of 10 mm was used as a drawn PET fiber 5.

<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 a polyethylene terephthalate, the sheath is a crystalline copolyester composed of polyethylene terephthalate, 1,4-butanediol and ε-caprolactone (glass transition point: 45 ° C., melting point: 175 ° C.), fiber diameter 15 μm, A core-sheath type polyester composite fiber having a fiber length of 5 mm and a core / sheath volume ratio of 50/50 was designated as core-sheath PET fiber 2.

<Core sheath PET fiber 3>
The core is polyethylene terephthalate, the sheath is a crystalline copolymerized polyester composed of polyethylene terephthalate and 1,4-butanediol (glass transition point: 86 ° C., melting point: 232 ° C.), fiber diameter 15 μm, fiber length 5 mm, The core-sheath polyester composite fiber having a core / sheath volume ratio of 50/50 was designated as core-sheath PET fiber 3.

<Core sheath PET fiber 4>
The core is polyethylene terephthalate, the sheath is a crystalline copolyester composed of polyethylene terephthalate, 1,4-butanediol and ε-caprolactone (glass transition point: 32 ° C., melting point: 154 ° C.), fiber diameter 15 μm, A core-sheath polyester composite fiber having a fiber length of 5 mm and a core / sheath volume ratio of 50/50 was designated as core-sheath PET fiber 4.

  The support bodies for semipermeable membranes for membrane separation activated sludge treatment of Examples 1 to 16 and Comparative Examples 1 to 3 were 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 1, dispersed at a dispersion concentration of 0.2% by weight for 5 minutes, and using a slanted / circular mesh paper machine, After forming the wet paper of the second surface layer on the inclined wire and forming the wet paper of the first surface layer on the circular mesh wire and laminating both wet papers, the surface temperature of 130 ° C. The wet nonwoven fabric (base papers 1 to 19) having a width of 1000 mm was obtained with a target of the basis weight shown in Table 1 by hot-pressure drying with a Yankee dryer.

(Thermal calendar processing)
The obtained base papers 1 to 19 were subjected to thermal calendering treatment under the conditions described in Table 2 in a metal roll-elastic roll calender unit, and membrane separation activities of Examples 1 to 16 and Comparative Examples 1 to 3 were performed. A support for a semipermeable membrane for sludge treatment was obtained. It processed so that the surface which contacted the metal roll by the 1st process might hit an elastic roll by the 2nd process.

  The following measurements and evaluations were performed on the membrane-permeable activated sludge treatment semipermeable membrane supports obtained in Examples 1 to 16 and Comparative Examples 1 to 3, and the results are shown in Tables 3 and 4.

(Basis weight of support for semipermeable membrane for membrane separation activated sludge treatment)
The basis weight was measured according to JIS P8124.

(Thickness and density of the semipermeable membrane support for membrane separation activated sludge treatment)
The thickness of the semipermeable membrane support was measured in accordance with JIS P8118.

(Adhesive strength between semipermeable membrane support and frame material)
The support for each 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 SENZHEN KEIJIGSTAR 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 Bonding was performed as shown in FIG. 1 at the ultrasonic fusion point. 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.), 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 at the time was measured. Based on this maximum load, the “adhesive strength between the semipermeable membrane support and the frame material” was evaluated.

(Adhesive strength between the first surface layer and the second surface layer)
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 overlapped so that the first surface layer and the second surface layer are in contact with each other, and an ultrasonic bonding machine (manufactured by SENZHEN KEIJIGSTAR TECHNOLOGY LTD, product name: MSK-800, head product number: N1 (4 mm × 4 mm )), The first surface layer and the second surface layer of the two semipermeable membrane supports were ultrasonically fused with an output of 5%, an original air pressure of 0.10 MPa, and an adhesion time of 1.0 second. The dots were bonded 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 was pulled up was measured at a constant speed of 100 mm / min until the two semipermeable membrane supports were peeled off. Based on this maximum load, “adhesive strength between the first surface layer and the second surface layer” was evaluated.

(Semipermeable membrane adhesion evaluation of semipermeable membrane support)
Using a constant speed coating device (trade name: TQC fully automatic film applicator, Cortec Co., Ltd.) having a certain clearance, the polyfluoride in which the second surface layer surface of the semipermeable membrane support is colored with magic ink (registered trademark) An N-methylpyrrolidone solution (concentration: 12%) of vinylidene (PVDF) is applied, washed with water and dried to form a PVDF membrane on the second surface layer of the support for semipermeable membrane, thereby producing a semipermeable membrane. did.

  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 adhesive tape (product name: Elpac (registered trademark) LP24, manufactured by Nichiban Co., Ltd.) cut to a width of 24 mm and a length of 30 mm is pasted on the first surface layer of the cut semipermeable membrane support only in a 10 mm length portion. The remaining width of 24 mm and length of 20 mm 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 first surface layer 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 semipermeable membrane adhesion. 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 evaluation between the fused portion of the first surface layer and the second surface layer and the semipermeable membrane)
Two semipermeable membrane supports, trimmed to a width of 130 mm and a length of 180 mm, are superposed so that the first surface layer and the second surface layer are in contact with each other, and an ultrasonic bonding machine (manufactured by SENZHEN KEIJIGSTAR TECHNOLOGY LTD) , Product name: MSK-800, head product number: N1 (4 mm × 4 mm)), output of 5%, original air pressure of 0.1 MPa, adhesion time of 1.0 second. The first surface layer and the second surface layer were bonded as shown in FIG. 5 at the ultrasonic fusion point. 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 second surface layer 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 (manufactured by Nichiban Co., Ltd., trade name: Elpac (registered trademark) LP12) cut to a width of 12 mm and a length of 30 mm is pasted on the first surface layer of the sample only for the 10 mm length, and the remaining width is 12 mm. The 20 mm portion is left as an adhesive portion. 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)
(Semipermeable membrane adhesion evaluation of semipermeable membrane support) About the semipermeable membrane produced by fuzzing on the surface of the semipermeable membrane support surface existing in a 10 cm wide and 10 cm long square of the semipermeable membrane 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 .

  As shown in Table 4, the support for a semipermeable membrane for membrane separation activated sludge treatment of Examples 1 to 16 is a core-sheath having a stretched polyester fiber, an unstretched polyester fiber as a binder fiber, and a copolymer polyester as a sheath. A first surface layer containing unstretched polyester fibers and core-sheath polyester composite fibers as binder fibers, and a second surface layer containing only unstretched polyester fibers as binder fibers. Since it was a multilayer nonwoven fabric, it had high adhesion to the frame material and good semipermeable membrane applicability.

  From the comparison between Examples 1 and 9, in the first surface layer, the support for a semipermeable membrane of Example 1 in which the binder fiber content is 60% by mass or less with respect to the entire fibers contained in the first surface layer. Had better adhesion to the frame material and better adhesion to the semipermeable membrane than the semipermeable membrane support of Example 9 in which the binder fiber content exceeded 60% by mass. In addition, from the comparison between Examples 2 and 10, in the first surface layer, the semipermeable membrane support of Example 2 in which the content of the binder fiber is 20% by mass or more with respect to the entire fibers contained in the first surface layer. The body has better adhesion between the semipermeable membrane support and the frame material than the semipermeable membrane support of Example 10 in which the binder fiber content is less than 20% by mass. Adhesion with the two surface layers was also good.

  From the comparison between Examples 3 and 4 and Examples 11 and 12, in the first surface layer, the content of the binder fiber is 20 to 60% by mass with respect to the entire fibers contained in the first surface layer, and the core sheath The support for a semipermeable membrane of Examples 3 and 4 in which the content of the type polyester composite fiber is in the range of 5 to 40% by mass is the core-sheath type, even if the content of the binder fiber is 20 to 60% by mass. The adhesiveness with the frame material was better than the support for the semipermeable membrane of Example 11 in which the content of the polyester fiber exceeded 40 mass. Moreover, even if content of binder fiber is 20-60 mass%, content with a core material is less than the support for semipermeable membranes of Example 12 whose content of polyester composite fiber is less than 5 mass%. The adhesion was excellent, and the adhesion between the first surface layer and the second surface layer was also good.

  From the comparison between Examples 5 and 13, in the second surface layer, the support for a semipermeable membrane of Example 5 in which the content of the binder fiber is 60% by mass or less with respect to the entire fibers contained in the second surface layer. Had better adhesion to the semipermeable membrane than the support for the semipermeable membrane of Example 13 in which the binder fiber content exceeded 60 mass%. Further, from the comparison between Examples 6 and 14, in the second surface layer, the semipermeable membrane support of Example 6 in which the content of the binder fiber is 20% by mass or more with respect to the entire fibers contained in the second surface layer. The body was superior in the coating property of the semipermeable membrane than the support for the semipermeable membrane of Example 14 in which the binder fiber content was less than 20% by mass.

  From a comparison between Examples 7 and 15, Example 7 containing a core-sheath type polyester composite fiber having a sheath of a copolyester having a glass transition point of 80 ° C. or lower in the first surface layer has a glass transition point of 80. The first surface layer and the second surface have better adhesion to the frame material than the support for the semipermeable membrane of Example 15 containing the core-sheath type polyester composite fiber having a copolyester having a temperature exceeding 0 ° C. as the sheath. The adhesion with the layer was also good. Moreover, from the comparison with Examples 8 and 16, Example 8 containing a core-sheath type polyester composite fiber having a sheath portion of a copolyester having a glass transition point of 40 ° C. or higher in the first surface layer has a glass transition point. Is superior to the support for a semipermeable membrane of Example 16 containing a core-sheath polyester composite fiber having a copolyester having a temperature of less than 40 ° C. as the sheath, and the first surface layer and the second layer Adhesion with the two surface layers was also good.

  Compared with Examples 1 to 16, the support for a semipermeable membrane of Comparative Examples 1 and 2 in which the core-sheath polyester composite fiber is not contained in the first surface layer has the adhesiveness to the frame material and the first surface layer and the first surface layer. The adhesion with the two surface layers was very poor.

  Compared to Examples 1 to 16, the support for the semipermeable membrane of Comparative Example 3 containing the core-sheath type polyester fiber in both the first surface layer and the second surface layer was a metal heated during the heat calendar process. There was a problem that the support for semipermeable membrane adhered to the roll and the sheet was cut. In addition, since the support for the semipermeable membrane is greatly contracted, a lot of wrinkles are generated, and the film is in the form of a film, it is difficult for the coating liquid to enter the support when the semipermeable membrane is applied. The adhesiveness was very poor, and was unusable.

  The support bodies for semipermeable membranes for membrane separation activated sludge treatment of Examples 17 to 25 and Comparative Examples 4 to 6 were produced under the following conditions.

(Manufacture of base paper)
Using the same raw material blending ratio (%) as shown in Table 5, the same method as that for base papers 1 to 19 was used to obtain a wet nonwoven fabric (base papers 20 to 31) having a width of 1000 mm with the basis weight shown in Table 5 as the target.

(Thermal calendar processing)
The obtained base papers 20 to 31 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 17 to 25 and Comparative Examples 4 to 6 were performed. A support for a semipermeable membrane for sludge treatment was obtained. It processed so that the surface which contacted the metal roll by the 1st process might hit an elastic roll by the 2nd process.

  The following measurements and evaluations were performed on the membrane-permeable activated sludge treatment semipermeable membrane supports obtained in Examples 17 to 25 and Comparative Examples 4 to 6, 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 16 and Comparative Examples 1 to 3.

(Thickness and density of the semipermeable membrane support for membrane separation activated sludge treatment)
The thickness was measured by the same method as in Examples 1 to 16 and Comparative Examples 1 to 3.

(Adhesive strength between semipermeable membrane support and frame material)
“Adhesive strength between the semipermeable membrane support and the frame material” was evaluated in the same manner as in Examples 1 to 16 and Comparative Examples 1 to 3.

(Adhesive strength between the first surface layer and the second surface layer)
“Adhesive strength between the first surface layer and the second surface layer” was evaluated in the same manner as in Examples 1 to 16 and Comparative Examples 1 to 3.

(Semipermeable membrane adhesion evaluation of semipermeable membrane support)
Tests were performed in the same manner as in Examples 1 to 16 and Comparative Examples 1 to 3, and “adhesiveness between the semipermeable membrane support and the semipermeable membrane” was evaluated according to the same criteria.

(Adhesion evaluation between the fused portion of the first surface layer and the second surface layer and the semipermeable membrane)
Tests were performed in the same manner as in Examples 1 to 16 and Comparative Examples 1 to 3, and “adhesiveness between the fused portion and the semipermeable membrane” was evaluated according to the same criteria.

(Semipermeable membrane applicability evaluation of semipermeable membrane support)
Tests were performed in the same manner as in Examples 1 to 16 and Comparative Examples 1 to 3, and “semi-permeable membrane coating property of semi-permeable membrane support” was evaluated according to the same evaluation criteria.

  As shown in Table 8, the support for a semipermeable membrane for membrane separation activated sludge treatment of Examples 17 to 25 is a core sheath having a stretched polyester fiber, an unstretched polyester fiber as a binder fiber, and a copolymer polyester as a sheath. A first surface layer containing unstretched polyester fibers and core-sheath polyester composite fibers as binder fibers, and a second surface layer containing only unstretched polyester fibers as binder fibers. Since it was a multilayer nonwoven fabric, it had high adhesion to the frame material and good semipermeable membrane applicability.

From the comparison between Examples 19 and 23, in the first surface layer, the support for a semipermeable membrane of Example 19 in which the binder fiber content is 20% by mass or more with respect to the entire fibers contained in the first surface layer. Has better adhesion between the semipermeable membrane support and the frame material than the semipermeable membrane support of Example 23 in which the binder fiber content is less than 20% by mass. Adhesion with the surface layer was also good.

  From the comparison between Examples 19 and 24, in the second surface layer, the support for a semipermeable membrane of Example 19 in which the content of the binder fiber is 20% by mass or more with respect to the entire fibers contained in the second surface layer. The coating property of the semipermeable membrane was superior to the support for the semipermeable membrane of Example 24 in which the binder fiber content was less than 20% by mass.

  From the comparison with Examples 20 and 25, in the first surface layer, the content of the binder fiber is 20 to 60% by mass with respect to the entire fibers contained in the first surface layer, and the core-sheath polyester composite fiber is contained. The support for the semipermeable membrane of Example 20 in which the amount is in the range of 5 to 40% by mass has a core-sheath polyester composite fiber content of 5 even if the binder fiber content is 20 to 60% by mass. The adhesion to the frame material was superior to that of the support for the semipermeable membrane of Example 25 of less than% by mass, and the adhesion between the first surface layer and the second surface layer was also good.

  Compared to Examples 17 to 25, the support for a semipermeable membrane of Comparative Examples 4 and 5 in which the core-sheath polyester composite fiber is not contained in the first surface layer has the adhesiveness to the frame material and the first surface layer and the first surface layer. The adhesion with the two surface layers was very poor.

  For Examples 17 to 25, the semipermeable membrane support of Comparative Example 6 containing a core-sheath polyester fiber in both the first surface layer and the second surface layer was a metal heated during the thermal calendar process. There was a problem that the support for semipermeable membrane adhered to the roll and the sheet was cut. In addition, since the support for the semipermeable membrane is greatly contracted, a lot of wrinkles are generated, and the film is in the form of a film, it is difficult for the coating liquid to enter the support when the semipermeable membrane is applied. The adhesiveness was very poor, and was unusable.

  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.

(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 first surface layer containing unstretched polyester fibers and core-sheath polyester composite fibers as binder fibers, and a second surface layer containing only unstretched polyester fibers as binder fibers. multilayer nonwoven der is, the sheath portion of the core-sheath type polyester composite fiber, membrane separation activated sludge process for semipermeable membrane supporting body, wherein the copolymerized polyester der Rukoto glass transition point 40 to 80 ° C. with .

( 2 ) In 1st surface layer, content of binder fiber is 20-60 mass% with respect to the whole fiber contained in 1st surface layer, and content of core-sheath-type polyester composite fiber is 5-40 mass%. The support for a semipermeable membrane for membrane separation activated sludge treatment according to the above (1 ) .

( 3 ) In the second surface layer, the membrane separation activated sludge treatment according to the above (1) or (2) , wherein the content of the binder fiber is 20 to 60% by mass with respect to the entire fibers contained in the second surface layer. Semipermeable membrane support.

( 4 ) A filtration membrane for membrane separation activated sludge treatment comprising a semipermeable membrane provided on the support for membrane separation activated sludge treatment according to any one of (1) to ( 3 ) above.

( 5 ) A module using the membrane for activated membrane sludge described in ( 4 ) above.

( 6 ) The module according to ( 5 ), wherein the module is at least one selected from the group consisting of a flat membrane module, a tube module, and a tubular module.

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. Examples 15 and 16 are reference examples.

(5) A module using the membrane separation activated sludge treatment membrane described in (4) above.

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 multilayer nonwoven fabric having a first surface layer containing unstretched polyester fibers and core-sheath polyester composite fibers as binder fibers, and a second surface layer containing only unstretched polyester fibers as binder fibers A support for semipermeable membrane for membrane separation activated sludge treatment, characterized in that:   The support for a semipermeable membrane for membrane separation activated sludge treatment according to claim 1, wherein the sheath of the core-sheath polyester composite fiber is a copolyester having a glass transition point of 40 to 80 ° C.   In the first surface layer, the content of the binder fiber is 20 to 60% by mass, and the content of the core-sheath polyester composite fiber is 5 to 40% by mass with respect to the entire fibers contained in the first surface layer. Item 3. The support for semipermeable membrane for membrane separation activated sludge treatment according to Item 1 or 2.   In the second surface layer, the content of the binder fiber is 20 to 60% by mass with respect to the entire fibers contained in the second surface layer. Membrane support.   A filtration membrane for membrane separation activated sludge treatment, comprising a support for a semipermeable membrane for membrane separation activated sludge treatment according to any one of claims 1 to 4 provided with a semipermeable membrane.   A module comprising the membrane 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.