JP2016026865A - Separation membrane element - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a separation membrane element which can stabilize the performance of separation and removal, particularly when the separation membrane element is operated under high pressure over a long period of time.SOLUTION: A separation membrane element of the present invention includes: a water collecting pipe; a separation membrane which includes a separation membrane body and a permeation side flow path material adhered to the permeation side surface of the separation membrane body and including a plurality of projections, and which is wound around the water collecting pipe; and a supply side flow path material arranged so as to face the supply side surface of the separation membrane. The projections each have a height of 0.15 mm or more and 0.35 mm or less. In the winding direction of the separation membrane, the average height of the projections arranged in a region within 20% of the length of the separation membrane from the outer end part of the separation membrane is 1.05 times or more and 2.0 times or less the average height of the projections arranged in a region within 50% of the length of the separation membrane from the inner end part of the separation membrane.SELECTED DRAWING: Figure 5

Description

  The present invention relates to a separation membrane element suitably used for separating components contained in a fluid such as liquid and gas.

  In the technology for removing ionic substances contained in seawater, brine, and the like, in recent years, the use of separation methods using separation membrane elements is expanding as a process for saving energy and resources. Separation membranes used in separation methods using separation membrane elements are classified into microfiltration membranes, ultrafiltration membranes, nanofiltration membranes, reverse osmosis membranes, and forward osmosis membranes in terms of their pore sizes and separation functions. These membranes are used, for example, in the production of drinking water from seawater, brine, and water containing harmful substances, industrial ultrapure water, and wastewater treatment and recovery of valuable materials. Depending on the separation component and separation performance to be used.

  There are various types of separation membrane elements, but they are common in that raw fluid is supplied to one surface of the separation membrane and permeate fluid is obtained from the other surface. The separation membrane element includes a large number of bundled separation membranes, so that the membrane area per separation membrane element is increased, specifically, the permeation obtained per separation membrane element. It is formed so that the amount of fluid is large. Various separation membrane elements such as spiral type, hollow fiber type, plate and frame type, rotating flat membrane type, and flat membrane integrated type have been proposed as the separation membrane element. .

  For example, spiral separation membrane elements are widely used for reverse osmosis filtration. The spiral type separation membrane element includes a central tube and a laminated body wound around the central tube. The laminate includes a supply side flow path material that supplies the raw fluid to the surface of the separation membrane, a separation membrane that separates components contained in the raw fluid, and a permeate side fluid that permeates the separation membrane and is separated from the supply side fluid. It is formed by laminating permeation-side flow path materials for guiding to the side. The spiral separation membrane element is preferably used in that a large amount of permeated fluid can be taken out because pressure can be applied to the raw fluid.

  Further, in the spiral type separation membrane element, in general, a net mainly made of a polymer compound is used as the supply side flow path material in order to form the flow path of the supply side fluid. As the separation membrane, a stacked type separation membrane is used. Multilayer separation membranes consist of a separation functional layer composed of a crosslinked polymer compound such as polyamide, a porous resin layer composed of a polymer compound such as polysulfone, and a polymer compound such as polyethylene terephthalate, laminated from the supply side to the permeation side. It is a separation membrane provided with the nonwoven fabric which becomes. Further, as the permeation side channel material, a knitted member called a tricot having a smaller interval than the supply side channel material is used for the purpose of preventing the separation membrane from dropping and forming the permeation side channel.

  In recent years, high performance of membrane elements has been demanded due to increasing demands for reducing water production costs. For example, in order to improve the separation performance of the separation membrane element and increase the amount of permeated fluid per unit time, it has been proposed to improve the performance of the separation membrane element member such as each flow path member. Specifically, a separation membrane element has been proposed in which the amount of water produced in the element is increased by disposing the resin on the permeate side of the separation membrane so that the adhesive force is 1 N / m or more (see Patent Document 1). .)

International Publication No. 2013/047744

  However, the above-described conventional separation membrane element has a problem that the structural stability of the element when operated at a high pressure for a long period of time is still not sufficient.

  Accordingly, an object of the present invention is to provide a separation membrane element that can stabilize the separation and removal performance when the separation membrane element is operated by applying a high pressure over a long period of time.

  The present invention is to solve the above-mentioned problems, and the separation membrane element of the present invention comprises a water collecting pipe, a separation membrane main body, and a plurality of protrusions fixed to the permeation side surface of the separation membrane main body. Separation comprising a separation membrane wound around the water collecting pipe provided with a permeate-side flow path material, and a supply-side flow path material disposed so as to face the supply-side surface of the separation membrane The height of the protrusion is 0.15 mm or more and 0.35 mm or less, and the length of the separation membrane is 20 from the outer end of the separation membrane in the surrounding direction of the separation membrane. The average height of the protrusions arranged in the region within% is 1.05 times or more of the average height of the protrusions arranged in the region within 50% of the length of the separation membrane from the inner end of the separation membrane. The separation membrane element is 2.0 times or less.

  According to a preferred aspect of the separation membrane element of the present invention, the coefficient of variation of the height of the protrusion disposed in the region within 50% of the length of the separation membrane from the inner end of the separation membrane in the surrounding direction is 0% or more and 10% or less.

  According to the present invention, it is possible to form a highly efficient and stable permeation-side flow path, and not only have separation component removal performance and high permeation performance, but also have excellent surrounding properties and good dimensional stability of the element. A high-performance and highly efficient separation membrane element can be obtained.

FIG. 1 is an exploded perspective view showing one embodiment of a separation membrane leaf used in the present invention. FIG. 2 is a plan view showing a separation membrane provided with a flow path material provided continuously in the length direction (second direction) of the separation membrane used in the present invention. FIG. 3 is a plan view showing a separation membrane provided with a channel material provided discontinuously in the length direction (second direction) of the separation membrane used in the present invention. FIG. 4 is a cross-sectional view of the separation membrane of FIGS. FIG. 5 is a developed perspective view showing one embodiment of the separation membrane element of the present invention in which a separation membrane is wound around the water collecting pipe. FIG. 6 is a schematic side view of the separation membrane used in the present invention. FIG. 7 is a cross-sectional view showing a schematic configuration of the separation membrane main body used in the present invention. It is an example of the method of arrange | positioning the sheet | seat which fixed the protrusion to the film | membrane leaf.

  Next, embodiments of the separation membrane element of the present invention will be described in detail. The separation membrane element of the present invention is wound around the water collection tube including a water collection tube, a separation membrane main body, and a permeation-side flow path member composed of a plurality of protrusions fixed to the permeation-side surface of the separation membrane main body. A separation membrane element comprising an enclosed separation membrane and a supply-side flow path material disposed so as to face the supply-side surface of the separation membrane, wherein the protrusion has a height of 0.15 mm And the average height of the protrusions disposed in a region within 20% of the length of the separation membrane from the outer end of the separation membrane in the winding direction of the separation membrane, The separation membrane element has an average height of 1.05 times or more and 2.0 times or less of an average height of protrusions arranged in a region within 50% of the length of the separation membrane from the inner end of the separation membrane.

[1. Separation membrane)
(1-1) Overview of Separation Membrane A separation membrane is a membrane that can separate components in a fluid supplied to the surface of the separation membrane and obtain a permeated fluid that has permeated the separation membrane. The separation membrane includes a separation membrane main body and a flow path material disposed on the separation membrane main body.

  As an example of such a separation membrane, the separation membrane 1 of the embodiment of the present invention includes a separation membrane main body 2 and a permeate-side flow path member 3 as shown in FIG. The separation membrane body 2 includes a supply-side surface 21 and a permeation-side surface 22.

  In the present invention, the “supply side surface” of the separation membrane body means a surface on the side of the separation membrane body 2 on which the raw fluid is supplied. Further, the “transmission side surface” means the opposite side surface. As will be described later, when the separation membrane main body 2 includes the base material 201 and the separation functional layer 203 as shown in FIG. 7, generally, the surface on the separation functional layer side is the surface 21 on the supply side. The substrate side surface is the transmission side surface 22.

  The permeate-side channel material 3 is provided so as to form a channel on the permeate-side surface 22. Details of each part of the separation membrane 1 will be described later.

  In the figure, the direction axes of the x-axis, y-axis and z-axis are shown. The x-axis may be referred to as a first direction and the y-axis may be referred to as a second direction. As shown in FIG. 1 and the like, the separation membrane main body 2 is rectangular, and the first direction and the second direction are parallel to the outer edge of the separation membrane main body 2. The first direction may be referred to as the width direction, and the second direction may be referred to as the length direction.

(1-2) Separation membrane body <Overview>
As the separation membrane body, a membrane having separation performance according to the method of use and purpose is used. The separation membrane main body may be formed of a single layer, or may be a composite membrane comprising a separation functional layer and a substrate. As shown in FIG. 7, in the composite membrane, a porous support layer 202 can be formed between the separation functional layer 203 and the base material 201.

<Separation function layer>
The thickness of the separation functional layer is preferably 5 nm or more and 3000 nm or less in terms of separation performance and transmission performance. In particular, for reverse osmosis membranes, forward osmosis membranes and nanofiltration membranes, the thickness is preferably 5 nm or more and 300 nm or less.

  The thickness of the separation functional layer can be measured in accordance with the conventional method for measuring the thickness of the separation membrane. For example, the separation membrane is embedded with resin, and an ultrathin section is prepared by cutting the separation membrane, and the obtained section is subjected to processing such as staining. Thereafter, the thickness can be measured by observation with a transmission electron microscope. When the separation functional layer has a pleat structure, measure the pleat structure located above the porous support layer in the cross-sectional length direction at intervals of 50 nm, measure the number of pleats, and obtain the thickness from the average. Can do.

  The separation function layer may be a layer having both a separation function and a support function, or may be configured to have only a separation function. “Separation functional layer” refers to a layer having at least a separation function.

  When the separation functional layer has both a separation function and a support function, a layer containing cellulose, polyvinylidene fluoride, polyethersulfone, polysulfone, or the like as a main component is preferably applied as the separation functional layer.

  On the other hand, as the separation functional layer, a crosslinked polymer compound is preferably used from the viewpoint of easy control of the pore diameter and excellent durability. In particular, from the viewpoint of excellent separation performance of components in the raw fluid, a polyamide separation functional layer obtained by polycondensation of a polyfunctional amine and a polyfunctional acid halide, an organic-inorganic hybrid functional layer, and the like are preferably used.

  The separation functional layer can be formed by polycondensation of monomers on the porous support layer.

  For example, the separation functional layer can contain polyamide as a main component. Such a film is formed by interfacial polycondensation of a polyfunctional amine and a polyfunctional acid halide by a known method. For example, by applying a polyfunctional amine aqueous solution to the porous support layer, removing excess amine aqueous solution with an air knife or the like, and then applying an organic solvent solution containing a polyfunctional acid halide, the polyamide separation functional layer Is obtained. In addition, the separation functional layer can have an organic-inorganic hybrid structure containing Si element or the like.

  For any separation functional layer, the surface of the membrane can be hydrophilized with, for example, an alcohol-containing aqueous solution or an alkaline aqueous solution before use.

<Porous support layer>
The porous support layer is a layer that supports the separation functional layer and can also be referred to as a porous resin layer.

  The material used for the porous support layer and the shape of the material can be formed by, for example, forming a porous resin on a substrate. As the porous support layer, polysulfone, cellulose acetate, polyvinyl chloride, and epoxy resin, or a mixture or laminate of them is used. From the viewpoint of high chemical, mechanical and thermal stability and easy control of the pore size, it is preferable to use polysulfone.

  The porous support layer gives mechanical strength to the separation membrane, and does not have separation performance like a separation membrane for components having a small molecular size such as ions. Regarding the pore size and pore distribution of the porous support layer, for example, the porous support layer may have uniform and fine pores, or the other side from the surface on the side where the separation functional layer is formed. It can be set as the structure which has distribution of the hole diameter so that a diameter may become large gradually toward this surface.

  In any case, the projected area equivalent circle diameter of the pores measured using an atomic force microscope or an electron microscope on the surface on the side where the separation functional layer is formed is 1 nm or more and 100 nm or less. preferable. In particular, in terms of interfacial polymerization reactivity and retention of the separation functional layer, the pores on the surface on the side where the separation functional layer is formed in the porous support layer may have a projected area equivalent circle diameter of 3 nm to 50 nm. preferable.

  The thickness of the porous support layer is preferably in the range of 20 μm or more and 500 μm or less, and more preferably in the range of 30 μm or more and 300 μm or less, for reasons such as giving strength to the separation membrane.

  The above-mentioned thickness and pore diameter of the porous support layer are average values, and the thickness of the porous support layer is measured at intervals of 20 μm in a direction orthogonal to the thickness direction by cross-sectional observation, and is an average value of 20-point measurement. Moreover, a hole diameter is an average value of each projected area circle equivalent diameter measured about 200 holes.

  Next, a method for forming the porous support layer will be described. The porous support layer is formed, for example, by applying an N, N-dimethylformamide (hereinafter sometimes referred to as DMF) solution of the above polysulfone on a base material described later, for example, a densely woven polyester cloth or nonwoven fabric. It can be produced by casting to a certain thickness and wet coagulating it in water.

  The porous support layer is “Office of Saleen Water Research and Development Progress Report” no. 359 (1968). In order to obtain a porous support layer having a desired form, the polymer concentration, the temperature of the solvent, and the poor solvent can be appropriately adjusted.

<Base material>
The separation membrane body can have a substrate from the viewpoint of the strength and dimensional stability of the separation membrane body. As the base material, it is preferable to use a fibrous base material in terms of strength, unevenness forming ability and fluid permeability.

  As the substrate, any of a long fiber nonwoven fabric and a short fiber nonwoven fabric can be preferably used. In particular, since the long fiber nonwoven fabric has excellent film-forming properties, when the polymer polymer solution is cast, the solution penetrates by over-penetration, the porous support layer peels off, Furthermore, it is possible to suppress the film from becoming non-uniform due to fluffing of the base material and the like, and the occurrence of defects such as pinholes.

  In addition, since the base material is made of a long-fiber non-woven fabric composed of thermoplastic continuous filaments, compared to short-fiber non-woven fabric, non-uniformity and film defects caused by fiber fluffing during casting of a polymer solution can be prevented. Can be suppressed. Furthermore, since the separation membrane is tensioned in the film-forming direction when continuously formed, it is preferable to use a long-fiber nonwoven fabric excellent in dimensional stability as a base material.

  In the long-fiber nonwoven fabric, in terms of moldability and strength, it is preferable that the fibers in the surface layer on the side opposite to the porous support layer have a longitudinal orientation than the fibers in the surface layer on the porous support layer side. With such a structure, not only a high effect of preventing membrane breakage and the like by maintaining strength is realized, but also a laminate comprising a porous support layer and a substrate when imparting irregularities to the separation membrane As a result, the shape of the surface of the separation membrane is stabilized.

  More specifically, the fiber orientation degree in the surface layer opposite to the porous support layer of the long-fiber nonwoven fabric is preferably 0 ° or more and 25 ° or less, and the fiber orientation degree in the porous support layer side surface layer. The orientation degree difference is preferably 10 ° or more and 90 ° or less.

  The separation membrane manufacturing process and the element manufacturing process include a heating process, but a phenomenon occurs in which the porous support layer or the separation functional layer contracts due to the heating. In particular, the shrinkage is significant in the width direction where no tension is applied in continuous film formation. Since shrinkage causes problems in dimensional stability and the like, a substrate having a small rate of thermal dimensional change is desired. In the nonwoven fabric, when the difference between the fiber orientation degree on the surface layer opposite to the porous support layer and the fiber orientation degree on the porous support layer side surface layer is 10 ° or more and 90 ° or less, the change in the width direction due to heat is suppressed. You can also.

  Here, the fiber orientation degree is an index indicating the direction of the fibers of the nonwoven fabric substrate constituting the porous support layer. Specifically, the fiber orientation degree is an average value of angles between the film forming direction when continuous film formation is performed, that is, the longitudinal direction of the nonwoven fabric base material and the fibers constituting the nonwoven fabric base material. That is, if the longitudinal direction of the fiber is parallel to the film forming direction, the fiber orientation degree is 0 °. If the longitudinal direction of the fiber is perpendicular to the film forming direction, that is, if it is parallel to the width direction of the nonwoven fabric substrate, the degree of orientation of the fiber is 90 °. Therefore, the fiber orientation degree is closer to 0 °, the longer is the vertical orientation, and the closer to 90 ° is the lateral orientation.

  The degree of fiber orientation is measured as follows. First, 10 small piece samples are randomly collected from the nonwoven fabric. Next, the surface of the sample is photographed at 100 to 1000 times with a scanning electron microscope. In the photographed image, 10 samples are selected for each sample, and the angle when the longitudinal direction (longitudinal direction, film forming direction) of the nonwoven fabric is 0 ° is measured. That is, the angle is measured for a total of 100 fibers per nonwoven fabric. An average value is calculated from the angles of 100 fibers thus measured. The value obtained by rounding off the first decimal place of the obtained average value is the fiber orientation degree.

  Moreover, it is preferable that the thickness of a base material is set to such an extent that the sum total of the thickness of a base material and a porous support layer exists in the range of 30 micrometers or more and 300 micrometers or less, or the range of 50 micrometers or more and 250 micrometers or less.

(1-3) Permeation side channel material <Overview>
A permeate-side channel material is provided on the permeate-side surface of the separation membrane body so as to form a permeate-side channel. “The permeate-side flow path material is provided so as to form a permeate-side flow path” means that when the separation membrane is incorporated into a separation membrane element described later, the permeated fluid that has permeated the separation membrane body reaches the water collecting pipe. It means that a permeate-side channel material is formed so as to be able to. Details of the configuration of the permeate-side channel material are as follows.

<Constituent component of permeate side channel material>
The permeate side channel material 3 is preferably formed of a material different from that of the separation membrane body 2. The different material means a material having a composition different from that of the material used in the separation membrane body 2. In particular, the composition of the permeate-side channel material 3 is preferably different from the composition of the surface of the separation membrane body 2 on which the permeate-side channel material 3 is formed, and any layer that forms the separation membrane body 2 It is preferable that the composition is different.

  A resin is preferably used as a component constituting the permeation side channel material. Specifically, from the viewpoint of chemical resistance, polyolefins such as ethylene vinyl acetate copolymer resin, polyethylene, and polypropylene, and copolymerized polyolefins are preferable, and polymers such as urethane resins and epoxy resins can also be selected. These resins can be used alone or as a mixture of two or more. In particular, since a thermoplastic resin is easy to mold, it is possible to form a permeate-side channel material having a uniform shape.

<Shape and arrangement of permeate side channel material>
<< Overview >>
Conventionally used tricots are knitted fabrics, and are composed of three-dimensionally intersecting yarns. That is, the tricot has a two-dimensional continuous structure. When such a tricot is applied as a permeate-side channel material, the height of the channel is smaller than the thickness of the tricot. That is, the entire thickness of the tricot cannot be used as the height of the flow path.

  On the other hand, as an example of the configuration of the present invention, the permeation side flow path members 3 shown in FIG. 1 and the like are arranged so as not to overlap each other. Therefore, all the heights (that is, the thicknesses) of the permeation-side flow path members 3 according to the embodiment of the present invention are utilized as the heights of the flow path grooves. Therefore, when the permeation side flow path member 3 of the embodiment of the present invention is applied, the flow path becomes higher than when a tricot having the same thickness as the height of the permeation side flow path member 3 is applied. That is, since the cross-sectional area of the flow path becomes larger, the flow resistance becomes smaller.

  In each of the drawings, a plurality of discontinuous permeation-side flow path members 3 are provided on one separation membrane body 2. “Discontinuous” refers to a structure in which a plurality of flow path materials 3 are separated from each other when the permeate-side flow path material 3 is peeled from the separation membrane body 2. On the other hand, members such as nets, tricots, and films have a continuous and integral shape even when separated from the separation membrane body 2.

  By providing a plurality of discontinuous permeation-side flow path members 3, the separation membrane 1 can suppress pressure loss when it is incorporated into a separation membrane element 100 described later. As an example of such a configuration, in FIG. 2, the permeation side flow path member 3 is formed discontinuously only in the first direction, and in FIG. 3, the permeation side flow path member 3 is formed in the first direction and the second direction. It is formed discontinuously in any direction.

  The separation membrane is preferably arranged in the separation membrane element so that the second direction coincides with the winding direction. That is, in the separation membrane element, the separation membrane is preferably arranged so that the first direction is parallel to the longitudinal direction of the water collection pipe 6 and the second direction is orthogonal to the longitudinal direction of the water collection pipe 6.

  In the example shown in FIG. 2, the flow path material 3 is provided discontinuously in the first direction, and is provided so as to be continuous from one end to the other end of the separation membrane body 2 in the second direction. That is, when the separation membrane 1 is incorporated into the separation membrane element 100 as shown in FIG. 5, the permeation side flow path material 3 in FIG. 2 continues from the inner end to the outer end of the separation membrane 1 in the surrounding direction. To be arranged. The inner side in the winding direction is the side close to the water collecting pipe in the separation membrane, and the outer side in the winding direction is the side far from the water collecting pipe in the separation membrane.

  The phrase “permeation-side flow path material is continuous in the second direction” means both the case where it is provided without interruption as shown in FIG. 2 and the case where it is substantially continuous even when it is interrupted as shown in FIG. Include. The “substantially continuous” form preferably means that the interval e (that is, the length of the portion where the transmission-side channel material is interrupted) in the second direction is 5 mm or less. Fulfill. In particular, it is more preferable to satisfy 1 mm or less, and a more preferable aspect is 0.5 mm or less. Further, the total value of the interval e is preferably 100 mm or less, more preferably 30 mm or less, from the beginning to the end of the row of permeation side flow path materials arranged in the second direction. Is a more preferred embodiment.

  When the flow path member 3 is provided without interruption as shown in FIG. 2, membrane drop is suppressed during pressure filtration. Membrane sagging is that the membrane falls into the channel and narrows the channel.

  Moreover, in FIG. 3, the channel material 3 is discontinuously provided not only in the first direction but also in the second direction. That is, the permeation-side channel material 3 is provided at intervals in the length direction. However, as described above, since the flow path member 3 is substantially continuous in the second direction, the film sagging is suppressed. Furthermore, since the permeation-side flow path material 3 is discontinuous in the two directions of the first direction and the second direction, the contact area between the permeation-side flow path material and the fluid is reduced, so that the pressure loss is reduced. In other words, this form is a configuration in which the permeation-side flow path 5 includes a branch point. That is, in the configuration of FIG. 3, the permeating fluid is divided by the permeation-side flow path material 3 while flowing through the permeation-side flow path 5 and can be further merged downstream.

  As described above, in FIG. 2, the permeation side flow path member 3 is provided so as to be continuous from one end to the other end of the separation membrane body 2 in the length direction (second direction). Further, in FIG. 3, the permeation side flow path member 3 is divided into a plurality of portions in the length direction (second direction), but these plurality of portions are arranged from one end to the other end of the separation membrane body 2. Is provided.

  The phrase “the permeate side channel material is provided so as to be lined up from one end to the other end of the separation membrane body 2” means that the permeate side channel material must be provided up to the edge of the separation membrane body. Absent. It means that the permeate-side channel material is disposed over the entire second direction of the separation membrane to such an extent that a permeate-side channel can be formed. It is not necessary to provide a permeate-side flow path material at a portion where the permeate-side surface is bonded to another separation membrane. In addition, for other reasons in terms of specifications or manufacturing, a region where the permeation-side flow path material is not disposed can be provided in some places such as near the outer edge of the separation membrane.

(Wound direction inside and outside area)
The permeation side surface of the separation membrane to which the protrusions are fixed is expressed as a percentage from the inner end to the outer end in the winding direction. It is 50% at the location where it is applied and 100% at the outer edge. The inner side in the winding direction refers to a region between the inner end portion and the portion that bisects the film length, that is, a region that exceeds 0% and is 50% or less. On the other hand, the outside in the winding direction is an area exceeding 80% and not more than 100%.

(Height c of permeate side channel material)
The height c of the permeate-side channel material is the difference in height between the permeate-side channel material and the surface of the separation membrane body. As shown in FIG. 4, the height c of the permeation-side channel material is the height of the highest part of the permeation-side channel material 3 and the permeation side surface of the separation membrane body in the cross section perpendicular to the second direction. It is a difference. That is, in the height, the thickness of the portion impregnated in the base material is not considered.

  The larger the height c of the permeate-side channel material, the smaller the flow resistance. Therefore, it is preferable that the height c of the permeate side channel material is 0.15 mm or more. On the other hand, the smaller the height c of the permeate-side channel material, the greater the number of membranes filled per element. Therefore, it is preferable that the height c of the permeate side channel material is 0.35 mm or less. Accordingly, the height c of the permeate side channel material is preferably 0.15 mm or more and 0.35 mm or less, and more preferably 0.2 mm or more and 0.35 mm or less.

  Further, the height of the permeate-side flow path material on the outer side in the surrounding direction of the separation membrane in the surrounding direction is 1.05 times or more and 2.0 times or less than the height on the inner side in the surrounding direction. The surrounding property can be improved, and the influence of shrinkage and deformation of the flow path material is hardly transmitted to the separation membrane body. As a result, curling of the separation membrane, membrane displacement and sealing failure caused by the separation membrane, and generation of wrinkles during winding are suppressed. That is, at the initial stage of winding, the amount of separation membrane leaf wound around the water collecting pipe is small, so the amount of work for winding is small, but the amount of separation membrane leaf increases as the surrounding is advanced, so the amount of work is large. Will also increase. At this time, if the height of the permeate side channel material on the outer side in the winding direction is within the above range, the curvature of the leaf when wrapped is reduced, and the influence of the shrinkage and deformation of the permeate side channel material is exerted on the separation membrane body. Difficult to communicate. As a result, curling of the separation membrane, membrane displacement and sealing failure caused by the separation membrane, and wrinkling during winding are suppressed, and the width of the leaf adhesive tends to be uniform. As a result, the obtained separation membrane element can operate stably even under long-time operation. In particular, an excellent effect can be exhibited when the height of the permeate-side flow path material increases substantially continuously outside the separation membrane in the surrounding direction.

  Moreover, it is preferable that the height c of the permeate-side channel material is designed so as not to cause a sudden height fluctuation that does not cause resistance during winding in the surrounding direction. The height of the permeate-side channel material can be measured using a cross-sectional observation with a microscope or a commercially available thickness meter in the corresponding region.

  The variation coefficient of the permeate-side channel material height in the inner region in the winding direction is 0% or more and 10% or less, so that the permeate-side channel material is prevented from being transferred to the separation membrane functional layer surface when winding the separation membrane. can do. If the coefficient of variation exceeds 10%, the separation membrane is distorted during filtration under pressure, so that defects may occur in the separation membrane.

  The variation coefficient of the height c of the permeate-side channel material can be calculated by measuring the height of the permeate-side channel material, and the standard deviation / permeation of the permeate-side channel material height in the inner region in the surrounding direction. It can represent with the average value of the side channel material height.

<Constituent component of permeate side channel material>
It is preferable that the permeate-side channel material 3 and the separation membrane main body 2 are formed of different materials. The different material means a material having a composition different from that of the material used in the separation membrane body 2. In particular, the composition of the permeate-side channel material 3 is preferably different from the composition of the surface of the separation membrane body 2 on which the permeate-side channel material 3 is formed, and any layer that forms the separation membrane body 2 It is preferable that the composition is different.

  As a material constituting the permeate-side flow path material 3, a resin is preferably used. Specifically, from the viewpoint of chemical resistance, polyolefins such as ethylene vinyl acetate copolymer resin, polyethylene, and polypropylene, and olefin copolymers are preferably used. A resin is preferably used as the material constituting the permeate-side flow path material 3 although the adhesiveness is slightly inferior to these. Specifically, resins such as urethane resins and epoxy resins can be selected, and these can be used alone or as a mixture of two or more. In particular, since a thermoplastic resin is easy to mold, a resin is preferably used as a material constituting the permeate-side flow path member 3 having a uniform shape.

  Prior to fixing the permeation-side flow path material 3 to the base material, the base material can be subjected to primer treatment.

<< Dimensions of separation membrane body and permeate side channel material >>
As shown in FIGS. 2 to 4, the following symbols a to f indicate the following.

a: Length of the separation membrane body 2 b: Distance between the permeation side flow path materials 3 in the width direction of the separation membrane body 2 c: Height of the permeation side flow path materials Difference in height from the transmission side surface 22)
d: Width of the permeate side channel material 3 e: Interval of the permeate side channel material in the length direction of the separation membrane body 2 f: Length of the permeate side channel material 3.

  For the measurement of the above values a to f, for example, a commercially available shape measurement system or a microscope can be used. Each of the above values is obtained by measuring at 30 or more locations on one separation membrane and dividing the sum of those values by the number of measured total locations to calculate the average value. Thus, each value obtained as a result of measurement at at least 30 locations is required to satisfy the above range.

(Length of separation membrane body a)
The length a of the separation membrane body is the distance from one end of the separation membrane body 2 to the other end in the second direction. When this distance is not constant, the length a of the separation membrane body can be obtained by measuring this distance at 30 or more positions in one separation membrane body 2 and obtaining an average value.

(Interval b in the width direction of the permeate-side channel material in the first direction (CD in FIG. 5))
The width direction interval b on the transmission side and transmission side in the first direction corresponds to the width of the flow path 5. When the width of one flow path 5 is not constant in one cross section, that is, when the side surfaces of two adjacent transmission side flow path materials 3 are not parallel, the width of one transmission side flow path 5 in one cross section The average value of the maximum value and the minimum value is measured, and the average value is calculated. As shown in FIG. 4, in the cross section perpendicular to the second direction, when the permeate-side flow path member 3 has a trapezoidal shape with a narrow top and a thin bottom, first, the upper part of two adjacent permeate-side flow path members 3 Measure the distance between and the distance between the lower parts, and calculate the average value. In any cross section of 30 or more locations, the interval between the permeation side flow path materials 3 is measured, and an average value is calculated in each cross section. Then, by further calculating the arithmetic average value of the average values thus obtained, the width direction interval b on the transmission side and the transmission side is calculated.

  Although the pressure loss decreases as the width b in the width direction on the transmission side and the transmission side increases, the film tends to drop. Conversely, the smaller the width direction interval b on the permeate side, the less likely the film will drop, but the greater the pressure loss. Considering the performance and stability as a separation membrane element, the width direction interval b on the permeate side permeate side is preferably 0.05 mm or more and 5 mm or less, and within this range, pressure loss can be reduced while suppressing membrane drop. can do. The width direction interval b on the transmission side transmission side is more preferably 0.2 mm or more and 2 mm or less, and further preferably 0.3 mm or more and 0.8 mm or less.

(Width d of permeate side channel material)
The width d of the permeation side channel material 3 is measured as follows. First, in one cross section perpendicular to the first direction, an average value of the maximum width and the minimum width of one permeation side flow path member 3 is calculated. That is, in the permeation-side channel material 3 having a thin upper part and a thick lower part as shown in FIG. 4, the width of the lower part and the upper part of the channel material are measured, and the average value is calculated. Such an average value is calculated in at least 30 cross sections, and an arithmetic average thereof is calculated. The width d of the permeation side flow path member 3 is preferably 0.2 mm or more or 0.3 mm or more. Since the width d of the permeate-side channel material 3 is 0.2 mm or more, the shape of the channel material can be maintained even when pressure is applied to the channel material 3 during operation of the separation membrane element. A path is formed stably. The width d of the permeate-side channel material 3 is preferably 2 mm or less or 1.5 mm or less. By setting the width d of the permeation-side flow path material 3 to 2 mm or less, it is possible to sufficiently secure the permeation-side flow path.

  By making the width d of the permeate-side channel material wider than the width direction interval b of the channel material in the width direction, the pressure applied to the permeate-side channel material can be dispersed.

  The permeate side channel material 3 is formed such that its length is greater than its width. Such a long channel material 3 is also referred to as a “wall-like object”.

  The width of the permeate-side channel material 3 can be different between the inner region and the outer region in the winding direction as long as the effect of the present invention is not impaired.

(Interval e in the length direction of the permeate-side channel material in the second direction (MD in FIG. 5))
The distance e in the length direction of the permeation-side flow path member 3 in the second direction is the shortest distance between the flow path members 3 adjacent in the second direction. As shown in FIG. 2, the permeate-side flow path material 3 is continuous from one end to the other end of the separation membrane body 2 in the second direction (in the separation membrane element, from the inner end to the outer end in the winding direction). In this case, the interval e in the length direction of the permeate-side channel material is 0 mm. In addition, as shown in FIG. 3, when the permeate-side channel material 3 is interrupted in the second direction, the interval e in the length direction of the permeate-side channel material is preferably 0 mm or more and 5 mm or less. Preferably they are 0 mm or more and 1 mm or less, More preferably, they are 0 mm or more and 0.5 mm or less. By setting the distance e in the length direction of the permeate-side flow path material within the above range, the mechanical load on the film is small even if the film falls, and the pressure loss due to the flow path blockage can be relatively small. .

(Permeation side channel material length f)
The length f of the permeate-side channel material 3 is the length of the permeate-side channel material 3 in the length direction (second direction) of the separation membrane main body 2. The length f of the permeate-side flow path member 3 is obtained by measuring the length of 30 or more permeate-side flow path members 3 in one separation membrane 1 and calculating an average value thereof. The length f of the permeate-side channel material can be set to a length a or less of the separation membrane body. When the length f of the permeate side channel material is equal to the length a of the separation membrane body, the permeate side channel material 3 is continuously provided from the inner end to the outer end in the winding direction of the separation membrane 1. It points to that. The length f is preferably 10 mm or more or 20 mm or more. By setting the length f of the permeate-side channel material to 10 mm or more, the channel is secured even under pressure.

(Permeate side channel material shape)
As the shape of the permeate-side channel material, a shape that reduces the flow resistance of the channel and stabilizes the channel when permeated can be selected. In these respects, in any cross section perpendicular to the surface direction of the separation membrane, the shape of the permeate-side channel material can be configured as a straight column shape, a trapezoidal shape, a curved column shape, or a combination thereof.

  For example, if the cross-sectional shape of the permeate-side channel material is trapezoidal, if the difference in length between the upper and lower bases is too large, membrane drop during pressure filtration tends to occur at the wider groove width. The ratio of the length of the upper base to the length of the bottom is preferably 0.6 or more and 1.4 or less, and more preferably 0.8 or more and 1.2 or less. From the viewpoint of reducing flow resistance, the shape of the permeate-side channel material is preferably a straight column shape perpendicular to the separation membrane surface described later. Further, the permeation side channel material may be formed so that the width becomes smaller at a higher portion, and conversely, the width from the separation membrane surface may be formed so that the width becomes wider at a higher portion. However, it can also be formed to have the same width. If the flow path material is not significantly crushed during pressure filtration, the permeation-side flow path material may have a rounded upper side.

  If the permeate-side channel material is a thermoplastic resin, the channel material can be freely adjusted so that the required separation characteristics and permeation performance conditions can be satisfied by changing the processing temperature and the type of thermoplastic resin selected. Can be adjusted.

  Further, the shape of the permeation-side channel material in the plane direction of the separation membrane may be, for example, a straight line as shown in FIG. 2, or may be a curved line, a sawtooth equiwave line, or a broken line.

  Further, when the shape of the permeation-side channel material in the planar direction of the separation membrane is linear, adjacent permeation-side channel materials can be arranged substantially parallel to each other. “Placing substantially parallel” means, for example, that the permeation-side channel material does not intersect on the separation membrane, and the angle formed by the longitudinal direction of two adjacent permeation-side channel materials is 0 ° or more and 30 ° or less. That the angle is 0 ° to 15 °, and that the angle is 0 ° to 5 °.

  Further, the angle formed by the longitudinal direction of the permeate-side channel material and the longitudinal direction of the water collecting pipe is preferably 60 ° or more and 120 ° or less, more preferably 75 ° or more and 105 ° or less, and 85 ° or more. It is a more preferable aspect that it is 95 degrees or less. By setting the angle formed by the longitudinal direction of the flow path material and the longitudinal direction of the water collecting pipe within the above range, the permeated water is efficiently collected in the water collecting pipe.

  In order to stably form the flow path, it is preferable that the separation membrane body can be prevented from dropping when the separation membrane body is pressurized in the separation membrane element. For this purpose, the contact area between the separation membrane body and the permeate-side channel material is large, and specifically, the area of the channel material relative to the area of the separation membrane body (projected area on the membrane surface of the separation membrane body) is large. preferable. On the other hand, in order to reduce pressure loss, it is preferable that the cross-sectional area of a flow path is wide. The cross section of the flow path is defined as a flow path in order to ensure a large contact area between the separation membrane body perpendicular to the longitudinal direction of the flow path and the permeate-side flow path material and a wide cross-sectional area of the flow path. The cross-sectional shape of the road is preferably a concave lens shape. Further, the permeation side flow path member 3 may have a straight column shape having no change in width in a cross-sectional shape in a direction perpendicular to the surrounding direction. In addition, if it is within a range that does not affect the performance of the separation membrane, a trapezoidal wall-like object having a change in width, an elliptical column, an elliptical cone, a four-sided cross-sectional shape in a direction perpendicular to the winding direction It can be shaped like a pyramid and a hemisphere.

  The shape of the permeate-side channel material is not limited to the shape shown in FIGS. When the permeate-side channel material is disposed on the permeate side surface of the separation membrane main body by adhering a molten material, for example, as in the hot melt method, the processing temperature and the type of hot melt resin to be selected are set. By changing, it is possible to freely adjust the shape of the permeation-side channel material so that the required separation characteristics and permeation performance conditions can be satisfied.

  In FIG. 1 to FIG. 3, the planar shape of the permeation side flow path member 3 is linear in the length direction. However, the permeation side flow path material 3 can be changed to other shapes as long as it is convex with respect to the surface of the separation membrane body 2 and does not impair the desired effect as the separation membrane element. That is, the shape in the planar direction of the permeation-side channel material can be a curved line, a wavy line, or the like. In addition, a plurality of permeation-side flow path materials included in one separation membrane can be formed so that at least one of width and length is different from each other.

(Projected area ratio)
The projected area ratio of the permeate-side channel material to the permeate-side surface of the separation membrane is 0.03 or more and 0.85 or less, particularly in that the flow resistance of the permeate-side channel is reduced and the channel is stably formed. Preferably, it is 0.15 or more and 0.85 or less, more preferably 0.2 or more and 0.75 or less, and further preferably 0.3 or more and 0.6 or less. It is an aspect. Here, the projected area ratio, cut out separation film 5 cm × 5 cm, the projected area of the permeation-side passage material obtained when projected onto the plane parallel to the surface direction of the separation membrane, cut area (25 cm ²⁾ The value divided by. This value can also be expressed by the above-described equation df / (b + d) (e + f).

(Defect rate)
The water that has permeated through the separation membrane passes through the permeation side flow path 5 and is collected in the water collecting pipe 6. In the separation membrane, water that has permeated through a region far from the water collection pipe 6, specifically, a region near the outer end in the winding direction (a region near the right end in FIG. 5) In the direction, it merges with the water that has passed through the inner region and heads toward the water collecting pipe 6. Therefore, in the permeate-side flow path 5, the amount of water that exists farther from the water collecting pipe 6 is small.

  Therefore, even if there is no permeate-side channel material in the region near the outer end in the winding direction as shown in FIG. 6, even if the flow resistance in that region is high, the total amount of water produced in the element The effect is minor. In FIG. 6, the length L <b> 3 of the region R <b> 3 where the permeation-side flow path material is not formed at the outer end in the winding direction is shorter than the length L <b> 1 of the separation membrane body 2.

  For the same reason, the formation accuracy of the permeate-side channel material is low in the region near the outer end in the winding direction, and the resin forming the permeate-side channel material is continuously applied in the first direction. The effect on the amount of water produced as an element is small. In this region, the same applies to the case where the separation membrane body is applied without a gap in the surface direction (xy plane).

  Accordingly, the distance from the outer end of the separation membrane body 2 in the surrounding direction to the outer end of the permeate-side flow path member 3 in the surrounding direction, specifically, the permeation at the outer end of the separation membrane main body 2 in the surrounding direction. The ratio of the length L3 (see FIG. 6) of the region R3 where the side channel material is not formed to the length L1 of the separation membrane body (corresponding to “a” described above) is 0%. It is preferably 30% or less, more preferably 0% or more and 10% or less, and particularly preferably 0 or more and 3% or less. This ratio is called a defect ratio.

  The defect rate is represented by L3 / L1 × 100 in FIG.

[2. Separation membrane element)
(2-1) Overview As shown in FIG. 4, the separation membrane element 100 includes the water collecting pipe 6 and any of the above-described configurations, and includes the separation membrane 1 wound around the water collecting pipe 6. The separation membrane element 100 further includes a member such as an end plate (not shown).

(2-2) Separation membrane <Overview>
The separation membrane 1 is wound around the water collecting pipe 6 and is arranged so that the width direction is along the longitudinal direction of the water collecting pipe 6. As a result, the separation membrane 1 is disposed so that the length direction is along the surrounding direction.

  Therefore, the permeation-side flow path member 3 that is a wall-like material is discontinuously arranged at least in the longitudinal direction of the water collecting pipe 6 on the permeation-side surface 22 of the separation membrane 1. Specifically, the flow path 5 is formed to be continuous from the outer end to the inner end of the separation membrane in the surrounding direction. As a result, the permeated water can easily reach the central pipe, that is, the flow resistance is reduced, so that a large amount of fresh water is obtained.

  The “inner side in the surrounding direction” and “outer side in the surrounding direction” are as shown in FIG. That is, the “inner end portion in the surrounding direction” and the “outer end portion in the surrounding direction” correspond to the end portion closer to the water collecting pipe 6 and the far end portion in the separation membrane 1, respectively.

  As described above, the channel material does not have to reach the edge of the separation membrane. In the present invention, for example, the outer end of the envelope membrane in the surrounding direction and the end of the envelope membrane in the longitudinal direction of the water collecting pipe The part includes an aspect in which the flow path material is not provided.

  FIG. 5 is a developed perspective view showing one embodiment of the separation membrane element of the present invention in which the separation membrane 1 is wound around the water collecting pipe 6. In FIG. 5, the separation membrane 1 is described as a surface on one side of the separation membrane leaf. In the figure, an arrow indicated by CD indicates the longitudinal direction of the water collecting pipe 6 and the width direction of the separation membrane (the first direction described above). An arrow indicated by MD indicates the length direction of the separation membrane and the direction of surrounding the water collecting pipe 6 (the above-described second direction).

<Separation membrane leaf and envelope membrane>
As shown in FIG. 1, the separation membrane forms a separation membrane leaf 4 (sometimes simply referred to as “leaf” in the present invention). In the leaf 4, the separation membrane 1 is arranged so that the supply-side surface 21 faces the supply-side surface 71 of another separation membrane 7 with a supply-side flow path material (not shown) interposed therebetween. In the separation membrane leaf 4, a supply-side flow path is formed between the supply-side surfaces of the separation membranes facing each other.

  Furthermore, the separation membrane 1 and the separation membrane 7 of the other separation membrane leaf facing the permeation side surface 22 of the separation membrane 1 form an envelope-like membrane by overlapping the two separation membrane leaves 4. . In the envelope-shaped membrane, between the opposite permeate side surfaces, in the rectangular shape of the separation membrane, only one side inside the winding direction is opened so that the permeate flows to the water collecting pipe 6, and the other three sides are sealed. Stopped. The permeate is isolated from the supply water by this envelope membrane.

  Examples of the sealing include a form bonded by an adhesive or hot melt, a form fused by heating or laser, and a form in which a rubber sheet is sandwiched. Sealing by adhesion is the simplest and most effective.

  In addition, on the supply side surface of the separation membrane, the inner end in the winding direction is closed by folding or sealing. Since the surface on the supply side of the separation membrane is sealed rather than folded, bending at the end of the separation membrane is unlikely to occur. Further, by suppressing the occurrence of bending in the vicinity of the crease, the generation of voids between the separation membranes and the occurrence of leaks due to the voids are suppressed when wound.

  In this way, by suppressing the occurrence of leaks, the recovery rate of the envelope-like film is improved. The recovery rate of the envelope-like film is obtained as follows. That is, an air leak test (air leak test) of the separation membrane element is performed in water, and the number of envelope-shaped membranes in which the leak has occurred is counted. Based on the count result, the ratio of (number of envelope films in which air leak has occurred / number of envelope films used for evaluation) is calculated as the recovery rate of the envelope film.

  A specific air leak test method is as follows. The end of the central pipe of the separation membrane element is sealed, and air is injected from the other end. The injected air passes through the holes of the water collecting pipe and reaches the permeation side of the separation membrane. However, as described above, if the separation membrane is not sufficiently folded and bent near the fold, Will move through the gap. As a result, the air moves to the supply side of the separation membrane, and the air reaches the water from the end (supply side) of the separation membrane element. Thus, air leak can be confirmed as the generation of bubbles.

  When the separation membrane leaf is formed by folding, the longer the separation membrane leaf (that is, the longer the original separation membrane), the longer the time required for folding the separation membrane. However, by sealing the supply side surface of the separation membrane instead of folding, an increase in manufacturing time can be suppressed even if the separation membrane leaf is long.

  In the separation membrane leaf and the envelope membrane, the separation membranes facing each other (separation membranes 1 and 7 in FIG. 1) may have the same configuration or different configurations. That is, in the separation membrane element, it is only necessary that at least one of the two permeation-side surfaces facing each other is provided with the above-described permeation-side flow path material. It can also be set as the structure on which the separation membrane which is not provided with the side channel material was piled up alternately. However, for convenience of explanation, in the separation membrane element and the explanation related thereto, the “separation membrane” includes a separation membrane that does not include the permeate-side channel material (for example, a membrane having the same configuration as the separation membrane main body).

  The separation membranes facing each other on the permeate side surface or the supply side surface may be two different separation membranes, or a single membrane folded.

(2-3) Permeation-side channel As described above, the separation membrane 1 includes the permeation-side channel material 3. By the permeation side flow path member 3, a permeation side flow path is formed inside the envelope-shaped membrane, specifically between the permeation side surfaces of the separation membranes facing each other.

(2-4) Supply side channel (channel material)
The separation membrane element 100 includes a supply-side flow path material in which the projected area ratio with respect to the separation membrane 1 exceeds 0 and is less than 1 between the surfaces on the supply side of the overlapping separation membranes (not shown). The projected area ratio of the supply-side channel material is preferably 0.03 or more and 0.50 or less, more preferably 0.10 or more and 0.40 or less, and particularly preferably 0.15 or more and 0.35 or less. is there. By setting the projected area ratio to 0.03 or more and 0.50 or less, the flow resistance can be kept relatively small. Here, the projected area ratio is the projected area obtained when the separation membrane and the supply-side channel material are cut out at 5 cm × 5 cm and the supply-side channel material is projected onto a plane parallel to the surface direction of the separation membrane. It is the value divided by the cut-out area.

  The height of the supply-side channel material is preferably more than 0.5 mm and not more than 2.0 mm, more preferably not less than 0.6 mm and not more than 1.0 mm, considering the balance of each performance and the operation cost as described later. It is as follows.

  The shape of the supply side channel material may have a continuous shape or a discontinuous shape. Examples of the supply-side channel material having a continuous shape include members such as a film and a net. Here, the continuous shape means that it is continuous over the entire range of the supply-side channel material. It is allowed that the continuous shape includes a discontinuous portion in a part of the supply-side channel material to such an extent that a problem such as a decrease in the amount of water produced does not occur. Further, the definition of “discontinuous” is as described for the permeation-side passage material on the permeation side. As the material of the supply side channel material, the same material as the separation membrane or a different material is used.

(2-5) Water Collection Pipe The water collection pipe 6 is configured so that permeated water flows therethrough, and the material, shape, size, and the like are not particularly limited. As the water collection pipe 6, for example, a cylindrical member having a side surface provided with a plurality of holes is preferably used.

[3. Method for manufacturing separation membrane element]
(3-1) Production of Separation Membrane Body The production method of the separation membrane body has been described above, but it can be summarized as follows.

  The resin is dissolved in a good solvent, and the resulting resin solution is cast on a substrate and immersed in pure water to combine the porous support layer and the substrate. Thereafter, as described above, a separation functional layer is formed on the porous support layer. Further, chemical treatment such as chlorine, acid, alkali and nitrous acid is performed to improve separation performance and permeation performance as necessary, and the monomer is washed to produce a continuous sheet of the separation membrane body.

  Unevenness can be formed on the separation membrane main body by embossing or the like before or after the chemical treatment.

(3-2) Arrangement of Permeation Side Channel Material The method for manufacturing a separation membrane includes a step of providing a continuous or / and discontinuous permeation side channel material on the permeation side surface of the separation membrane body. This step can be performed at any time during the manufacture of the separation membrane. For example, the permeation side channel material may be provided before the porous support layer is formed on the base material, and after the porous support layer is provided and before the separation functional layer is formed. It may be provided and may be performed after the separation functional layer is formed and before or after the above-described chemical treatment is performed.

  The method for disposing the permeate-side channel material includes, for example, a step of disposing a soft material on the separation membrane and a step of curing it. Specifically, ultraviolet curable resin, chemical polymerization, hot melt, drying, and the like are used for the arrangement of the transmission side flow path material. In particular, hot melt is preferably used. Specifically, a step of softening a material such as a resin by heat (thermal melting), a step of placing the softened material on a separation membrane, and curing the material by cooling. A step of fixing on the separation membrane.

  Examples of the method for arranging the permeation side channel material include coating, printing, spraying, and the like. Examples of the equipment used include a nozzle type hot melt applicator, a spray type hot melt applicator, a flat nozzle type hot melt applicator, a roll type coater, an extrusion type coater, a printing machine, and a sprayer.

(3-3) Formation of supply-side flow path When the supply-side flow path material is a discontinuous member formed of a material different from that of the separation membrane main body, the formation of the supply-side flow path material includes a permeation-side flow path. The same methods and timings as the material formation can be applied.

  When the supply-side flow path is a continuously formed member such as a net, after the separation membrane is manufactured by arranging the permeation-side flow path material in the separation membrane body, the separation membrane and the supply-side flow are It can be formed by overlapping the road material.

(3-4) Formation of Separation Membrane Leaf As described above, the separation membrane leaf may be formed by folding the separation membrane so that the surface on the supply side faces inward. It can also be formed by laminating films.

  It is preferable that the manufacturing method of the separation membrane element includes a step of sealing the inner end portion in the surrounding direction of the separation membrane on the surface on the supply side. In the sealing step, the two separation membranes are overlapped so that the surfaces on the supply side face each other. Further, the inner end in the winding direction of the stacked separation membranes, that is, the left end in FIG. 5 is sealed.

  Examples of the method of “sealing” include adhesion by an adhesive or hot melt, fusion by heating or laser, and a method of sandwiching a rubber sheet. Sealing by adhesion is the simplest and most effective.

  At this time, a supply-side channel material formed separately from the separation membrane can be disposed inside the overlapped separation membrane. As described above, the arrangement of the supply-side flow path member can be omitted by providing a difference in height in advance on the supply-side surface of the separation membrane by embossing or resin coating.

  Either the supply side surface sealing or the permeation side surface sealing (formation of an envelope-shaped membrane) may be performed first. It is also possible to perform the sealing of the surface on the transmission side in parallel. However, in order to suppress the generation of wrinkles in the separation membrane during winding, an adhesive or hot melt at the end in the width direction is allowed so that adjacent separation membranes are allowed to shift in the length direction due to winding. It is preferable to complete the solidification or the like, that is, the solidification for forming the envelope film, after the end of the winding.

(3-5) Formation of Envelope-shaped Membrane Folding one separation membrane so that the surface on the permeate side faces inward, or stacking two separation membranes so that the permeation side faces inward By attaching them together, an envelope film can be formed. In the rectangular envelope film, the other three sides are sealed so that only one end in the length direction is opened. Sealing can be performed by adhesion with an adhesive or hot melt, or fusion by heat or laser.

  The amount of the adhesive applied is preferably such that the width of the portion to which the adhesive is applied is 10 mm or more and 100 mm or less after the separation membrane leaf is wrapped around the water collecting pipe. As a result, the separation membrane is securely bonded, and the inflow of the raw fluid to the permeate side is suppressed. Also, a relatively large effective membrane area can be secured.

(3-6) Separation of Separation Membrane A conventional element manufacturing apparatus can be used for manufacturing the separation membrane element. In addition, as an element manufacturing method, a method described in a reference document (see Japanese Patent Publication No. 44-14216, Japanese Patent Publication No. 4-11928 and Japanese Patent Laid-Open No. 11-226366) can be used. The details are as follows.

  When the separation membrane is wrapped around the water collecting pipe, the separation membrane is arranged so that the closed end of the separation membrane leaf, that is, the closed portion of the envelope-shaped membrane faces the water collecting pipe. By wrapping the separation membrane around the water collecting pipe in such an arrangement, the separation membrane is wound in a spiral shape.

  If a spacer such as a tricot or base material is wrapped around the water collection pipe, the adhesive applied to the water collection pipe will not flow easily when the element is wrapped, leading to suppression of leakage, and the flow path around the water collection pipe Secured stably. In this case, the spacer is preferably wound longer than the circumference of the water collecting pipe.

  By surrounding the tricot around the water collecting pipe, the adhesive applied to the water collecting pipe is difficult to flow when the element is wrapped, leading to suppression of leakage, and further, the flow path around the water collecting pipe is stably secured. In this case, the tricot is preferably wound longer than the circumference of the water collecting pipe.

(3-7) Other steps The method for manufacturing a separation membrane element may include a step of further winding a film, a filament, and the like around the outer periphery of the separation membrane formed as described above. Further steps, such as edge cutting for trimming the ends of the separation membrane in the longitudinal direction of the water tube and attachment of end plates, can be included.

[4. Other forms of separation membrane element]
<Configuration of separation membrane element>
Another embodiment of the separation membrane element will be described. In addition, the above-mentioned matter is applied about the structure which is not mentioned below, a manufacturing process, and utilization.

  In this embodiment, as shown in FIG. 8, the protrusion 3 is fixed to a sheet different from the separation membrane. That is, as shown in FIG. 8, the separation membrane element includes a separation membrane 20 </ b> A and a permeation side flow path member 14 including the sheet 13 and the protrusion 3 fixed on the sheet 13.

  The separation membrane element of the present embodiment is manufactured by the same method as the separation membrane element including the leaf shown in FIG. 1 except that the separation membrane element includes a step of sandwiching the permeation side channel material between the separation membranes.

<Separation membrane>
Unlike the separation membrane 1 in FIG. 1, the separation membrane 20 </ b> A does not include the protrusion 3. That is, as the separation membrane 20A, the same configuration as that of the separation membrane main body 2 of the embodiment of FIG. 1 is adopted. The separation membrane 20A is arranged so that the surfaces on the permeate side and the surfaces on the supply side face each other.

<Permeate channel material>
The permeate-side channel material 14 is disposed between the permeate-side surfaces 122 of the two separation membranes 20A. The surface on the supply side of the separation membrane is indicated by reference numeral “121”. More specifically, the two separation membranes 20A are bonded (sealed) in the same manner as the separation membrane 2 and the separation membrane 7 in FIG. It is preferable that the sheet 13 of the permeation-side flow path material 14 exists between the separation membranes in at least a part of the adhesion portion. In FIG. 8, the size of the sheet 13 and the size of the separation membrane 20A are shown to be the same, but actually, the sheet may be larger or the separation membrane may be larger.

  The case where the protrusion is fixed to the separation membrane and the case where the protrusion is fixed to a sheet different from the separation membrane are common in that the protrusion is fixed to the sheet-like member. . In this document, for convenience of explanation, a sheet-like member provided as a member different from the separation membrane is referred to as a “sheet”.

<Sheet>
The porosity of the sheet 13 is preferably 20% or more and 90% or less, and particularly preferably 45% or more and 80% or less.

  If the accuracy of the arrangement of the protrusions is insufficient, the groove between the protrusions may be blocked. However, when the porosity of the sheet is 20% or more, the permeated water can move to another groove through the gap of the sheet 13, and the amount of water produced by the separation membrane element increases. Furthermore, since the resin constituting the protrusion 3 can be appropriately impregnated into the sheet 13, peeling of the protrusion 3 from the sheet 13 can be suppressed. Moreover, since the sheet 13 can be appropriately impregnated with the adhesive that seals between the separation membranes, the supply water can be prevented from flowing into the permeate-side flow path.

  Moreover, it can suppress that resin which comprises the protrusion 3 impregnates to the back of the sheet | seat 13 because a porosity is 90% or less. When the resin is impregnated to the back of the sheet 13, the thickness of the sheet 13 becomes uneven at the resin-impregnated portion and the surrounding portion. Moreover, the breadth of the adhesive agent which adhere | attaches leaves can be moderately suppressed because the porosity is 90% or less. As a result, it is possible to secure a region where the adhesive is not applied after the separation membrane element is formed, that is, a region (effective membrane area) where pressure filtration functions effectively. Thereby, the fall of the amount of fresh water of a separation membrane element can be suppressed.

  Here, the porosity means the ratio of voids per unit volume of the substrate. The porosity is obtained by dividing the value obtained by subtracting the dry weight of the base material from the weight of the pure water contained in the base material by the apparent volume of the base material at the time of drying. Calculated.

  The thickness of the sheet 13 is preferably 0.2 mm or less. In order to seal between the permeation side surfaces of the two separation membranes, it is preferable that the sheet 13 sandwiched between the separation membranes at the sealing location is impregnated with an adhesive. When the thickness of the sheet 13 is 0.2 mm or less, the adhesive is impregnated throughout in the thickness direction of the sheet 13, so that it is possible to prevent the supply water from being mixed into the permeated water. However, even if the thickness of the sheet 13 exceeds 0.2 mm, the separation membrane can be sealed with an adhesive if the porosity of the sheet 13 is 80% or more. Moreover, since the intensity | strength of the sheet | seat 13 is securable because the thickness of the sheet | seat 13 is 0.02 mm or more, damage to the sheet | seat 13 can be suppressed.

  In particular, if the thickness of the sheet 13 is 0.02 mm or more and 0.2 mm or less, the porosity is preferably 20% or more and 80% or less, and the thickness of the sheet 13 is more than 0.02 mm and 0.4 mm or less. If present, the porosity is more preferably 30% or more and 90% or less.

  Specifically, a nonwoven fabric is preferably used as the sheet 13. As the sheet 13, for example, the same material and structure as the base material of the separation membrane described above are applied.

<Protrusions>
For the protrusions fixed to the sheet, the configuration (that is, the shape, dimensions, arrangement, material, etc.) described for the protrusions fixed to the base material of the separation membrane with reference to FIG. In addition, the permeation side channel material of the present embodiment is manufactured by providing protrusions on the sheet by the same method as that for providing protrusions on the separation membrane.

  The protrusions may be provided on either side of the sheet or may be provided on both sides. In any case, the permeation-side channel material is arranged so as to be sandwiched between the permeation-side surfaces of the two separation membranes, and the surface on which the projections of the permeation-side channel material are provided is on the permeation side of the separation membrane. Opposite the surface.

  The relationship between the height c of the projection and the thickness H1 of the sheet will be described. The ratio (c / H0) of the height c of the protrusions to the sum H0 of the sheet thickness H1 and the height c of the protrusions is preferably 0.05 or more. This is because a wide flow path can be secured. On the other hand, when the ratio (c / H0) is 0.7 or less, the sheet can be prevented from being broken or damaged by the protrusions when the sheet is wound while tension is applied. This is because the larger the ratio (c / H0), the greater the load on the sheet of protrusions and the lower the physical durability of the sheet.

  When the ratio (c / H0) is 0.13 or less, the porosity of the sheet is preferably 30% or more and 90% or less. When the ratio (c / H0) exceeds 0.13 (or 0.15 or more) and is 0.7 or less, the porosity of the sheet is 20% or more and 80% or less. Is preferred.

  Next, although the separation membrane element of the present invention will be described in more detail with reference to examples, the present invention is not limited to these examples. The “permeate-side channel material” here refers to a material fixed to the permeate-side surface of the separation membrane body, and the “projection” refers to a material fixed to the above-described sheet.

(Height of permeate-side channel material (or protrusions) inside and outside the winding direction)
The separation membrane element obtained by the method described later was disassembled, and one separation membrane leaf was arbitrarily cut out and divided into two equal parts at the folding position. Next, it divides into 100 in the film surrounding direction obtained by bisecting, and there is an elevation difference of 10 μm or more for each of the above 100 samples using Keyence high precision shape measurement system KS-1100. Five locations were measured, and the sum of the height values was divided by the total number of locations to calculate the permeate-side channel material (or protrusion) height of each sample.

  Then, from the inner side to the outer side in the winding direction, the total height of each sample / the number of samples (50) is calculated for 50 samples obtained at positions 0% to 50% from the inner end, and the winding is performed. The permeation side channel material (or protrusion) inside the surrounding direction was set to the height.

  From the inner side to the outer side in the surrounding direction, the total height of each sample / number of samples (20) is calculated for 20 samples obtained at positions 80% to 100% from the inner end, and the surrounding direction The height of the permeate-side flow path material (or protrusion) on the outer side.

(Height ratio of the permeate-side channel material (or protrusion) on the outside in the surrounding direction / inside the surrounding direction)
The height ratio of the permeation side channel material was calculated by the following equation.
-Permeation-side channel material height on the outer side in the surrounding direction / permeation-side channel material (or protrusion) on the inner side in the surrounding direction
(Height ratio of the permeate-side channel material (or protrusion) on the outside in the surrounding direction / inside the surrounding direction)
The standard deviation of the permeation-side channel material height (or projection) is divided by the average value for 50 samples obtained from the inner end to the outer end in the winding direction at positions 0% to 50%. Calculated.

(Pitch and spacing of permeate side channel material (or projection))
Using a scanning electron microscope (S-800) (manufactured by Hitachi, Ltd.), a cross section of 30 arbitrary transmission side flow path materials was photographed at a magnification of 30 times, and the permeation side flow path material (or The horizontal distance from the apex of the projections to the apex of the adjacent permeate-side channel material was measured, and the average value was calculated as the pitch.

  Further, the interval b was measured by the method described above in the photograph in which the pitch was measured.

(Displacement resistance)
Winding deviation was measured for each of 15 separation membrane elements produced in Examples and Comparative Examples described later. Winding deviation is calculated by {element width after winding-separation membrane width used for winding}. In all Examples and Comparative Examples, the width of the separation membrane used for the winding was 1000 mm. Moreover, the element width after winding is the length of the separation membrane winding body in the longitudinal direction of the water collecting pipe.

  The average value of the winding deviations of the 15 elements thus measured was calculated. Furthermore, the ratio (%) of the average winding deviation for the elements of each Example and Comparative Example to the average winding deviation for the element of Comparative Example 1 was calculated. These average values are shown in Tables 1 to 3 as deviation resistance (%).

(durability)
For the separation membrane or separation membrane element, a cycle of ending the operation by operating for 1 minute under conditions of an operating pressure of 3 MPa and a temperature of 25 ° C. using a NaCl aqueous solution having a concentration of 2,000 mg / L and pH 6.5 as raw water. Stop) was repeated 10,000 times.

Thereafter, most of the water remaining in the separation membrane element was removed, and vacuum suction was performed from one end of the water collecting pipe at a pressure of −100 kPa using a vacuum pump. When the degree of vacuum reached 90 kPa (that is, pressure -90 kPa), the cock provided in the pipe connecting the vacuum pump and the separation membrane element was closed to maintain the pressure inside the element. Thereafter, the sealing property of the element was evaluated according to the following criteria. The higher the element vacuum after 15 seconds, the higher the sealing performance. In the present invention, “excellent” and “good” were regarded as acceptable.
Excellent: Element vacuum after 15 seconds exceeds 75 kPa and less than 90 kPa Good: Element vacuum after 15 seconds exceeds 65 kPa and less than 75 kPa Possible: Element vacuum after 15 seconds exceeds 55 kPa and not more than 65 kPa: Element vacuum after 15 seconds is 55 kPa or less.

  The above evaluation was carried out on 15 elements, and the most obtained result was regarded as durability.

Example 1
On a non-woven fabric made of polyethylene terephthalate fibers (single fiber fineness: 1 dtex, thickness: about 0.09 mm, density 0.80 g / cm ³ ), a 15.0% by mass DMF solution of polysulfone at a room temperature of 180 μm ( 25 ° C.), immediately immersed in pure water for 5 minutes, and immersed in warm water at 80 ° C. for 1 minute to form a porous reinforced polysulfone support membrane (thickness 0.13 mm) Was made.

  Thereafter, the obtained porous support layer roll was unwound, and the polysulfone surface was coated with an aqueous solution of 2.0% by mass of m-PDA (metaphenylenediamine) and 4.2% by mass of ε-caprolactam. Nitrogen was blown to remove the excess aqueous solution from the surface of the support membrane, and then an n-decane solution containing 0.06% by mass of trimesic acid chloride was applied so that the surface was completely wetted. Then, the excess solution was removed from the membrane by air blow and washed with water at a temperature of 50 ° C. to obtain a separation membrane roll.

Next, a flow path material was formed on the permeation side of the separation membrane. That is, using a nozzle loaded with a comb-like shim while adjusting the temperature of the backup roll to 15 ° C., polypropylene (MFR 1000 g / 10 min at 80 ° C. and load 2.16 kgf / cm ² , 80% by mass) / Styrenic elastomer ("DYNARON · SEBS · 8630P", 10% by mass, manufactured by JSR) was applied to the permeate side of the separation membrane to produce a permeate-side channel material that was continuous in the length direction of the membrane. . The resin temperature was 215 ° C., and the processing speed was 4.5 m / min. The shape of the obtained permeation side channel material was as shown in Table 1.

  The obtained separation membrane is folded and cut, and the net (thickness: 0.7 mm, pitch: 5.2 mm × 5 mm, fiber diameter: 0.35 mm, projected area ratio: 0.13) is used as the supply-side channel material. 26 leaves having a width of 900 mm and a leaf length of 800 mm were produced.

  An adhesive was manually applied to the leaf thus obtained, and this was tricot (thickness: 0.2 mm, groove width: 0.2 mm, ridge width: 0.3 mm, groove depth: 0.1 mm). ) Was previously spirally wrapped around an ABS water collecting tube (width: 1,020 mm, diameter: 30 mm, number of holes 40 × 1 linear line). The adhesive that bonds the leaves is referred to as “leaf adhesive”. As the leaf adhesive, polyurethane in which the main component isocyanate and the curing agent polyol were mixed in a ratio of 1: 2 was used.

  An 8-inch separation membrane element was produced by further winding the film on the outer periphery of the envelope-like membrane that was manually wound and fixing it with tape, followed by edge cutting, end plate attachment, and filament winding. The membrane width in the effective membrane area was 900 mm. When this separation membrane element was put in a pressure vessel and operated under the above-mentioned conditions, the slip resistance and durability were as shown in Table 1.

(Examples 2 to 7)
A separation membrane was produced in the same manner as in Example 1 under conditions not specifically mentioned. Specifically, in forming the permeate side channel material on the permeate side of the separation membrane, the distance between the backup roll and the nozzle and the processing speed are changed, and the height of the permeate side channel material is shown in Table 1 and Table 1. A separation membrane was prepared in the same manner as in Example 1 except that the change was made as in 2. Subsequently, a separation membrane element was produced in the same manner as in Example 1.

  An 8-inch separation membrane element was produced by further winding the film on the outer periphery of the envelope-like membrane that was manually wound and fixing it with tape, followed by edge cutting, end plate attachment, and filament winding. The membrane width in the effective membrane area was 900 mm. When this separation membrane element was put in a pressure vessel and operated under the above-mentioned conditions, the slip resistance and durability were as shown in Tables 1 and 2.

(Example 8)
Instead of forming protrusions on the substrate side of the separation membrane, the sheet was made of paper-made nonwoven fabric (yarn diameter: 1 dtex, thickness: about 0.03 mm, porosity 25%), and the protrusions shown in Table 2 were arranged Except for the above, a separation membrane element was produced in the same manner as in Example 7.

  When this element was put in a pressure vessel and operated under the above-mentioned conditions to obtain permeated water, the element performance was as shown in Table 2.

(Comparative Examples 1-3)
In forming the channel material on the permeation side of the separation membrane, it was carried out while changing the distance between the backup roll and the nozzle and the processing speed, and the height of the permeation side channel material was changed as shown in Table 3 A separation membrane was prepared in the same manner as in Example 1. Subsequently, a separation membrane element was produced in the same manner as in Example 1.

  In an effective membrane area, an 8-inch separation membrane element was produced by further winding a film around the periphery of an envelope-shaped envelope manually wrapped and fixing with a tape, followed by edge cutting, end plate mounting, and filament winding. The membrane width was 900 mm. When this separation membrane element was placed in a pressure vessel and operated under the above-described conditions, the slip resistance and durability were as shown in Table 3.

  As is clear from these results, it is clear that the separation membrane element of the example of the present invention has high water production performance, stable operation performance, and excellent removal performance.

1, 20A Separation membrane 121 Supply side surface 122 Permeation side surface
2 Separation membrane body 201 Base material 202 Porous support layer 203 Separation functional layer
3 Permeation side channel material 31 Projection
4 Separation membrane leaf
5 Permeate channel
6 water collecting pipe
7 Separation membrane 13 Sheet 14 Permeation side channel material (sheet-like)
21 Supply side surface 22 Permeate side surface 71 Supply side surface 72 Permeate side surface 100 Separation membrane element
a Length of separation membrane body
b Spacing in the width direction of the separation membrane body in the width direction
c Projection height
d Width of protrusion
e Distance in the length direction of protrusions
f Projection length L1 Separation membrane body length
L3 Length of the region where the permeation side flow path material is not provided at the outer peripheral end of the separation membrane R3 Region where the permeation side flow channel material is not provided at the outer peripheral end of the separation membrane

Claims (4)

Water collecting pipe,
A separation membrane wrapped around the water collecting pipe, comprising a separation membrane main body and a permeation-side flow path member comprising a plurality of protrusions fixed to the permeation-side surface of the separation membrane main body;
A separation membrane element comprising a supply-side flow path member arranged to face the supply-side surface of the separation membrane,
The height of the protrusion is 0.15 mm or more and 0.35 mm or less,
And in the winding direction of the separation membrane, the average height of the protrusions arranged in a region within 20% of the length of the separation membrane from the outer end portion of the separation membrane is from the inner end portion of the separation membrane. A separation membrane element characterized by being 1.05 times or more and 2.0 times or less the average height of protrusions arranged in a region within 50% of the length of the separation membrane. Water collecting pipe,
A permeation-side channel material that is a sheet having a separation membrane body and a protrusion disposed on the permeation-side surface of the separation membrane body;
A separation membrane element comprising a supply-side flow path member arranged to face the supply-side surface of the separation membrane body,
The height of the protrusion is 0.15 mm or more and 0.35 mm or less,
And in the winding direction of the permeation side channel material, the average height of the protrusions arranged in the region within 20% of the length of the permeation side channel material from the outer end portion of the permeation side channel material, It is 1.05 times or more and 2.0 times or less of the average height of the protrusions arranged in the region within 50% of the length of the permeation side channel material from the inner end of the permeation side channel material. Characteristic separation membrane element.   The coefficient of variation of the height of the protrusions arranged in a region within 50% of the length of the separation membrane from the inner end in the winding direction of the separation membrane is 0% or more and 10% or less. The separation membrane element described.   The variation coefficient of the height of the protrusion disposed in the region within 50% of the length of the permeate side channel material from the inner end in the surrounding direction of the permeate side channel material is from 0% to 10%. 3. The separation membrane element according to claim 2, wherein

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