WO2015016253A1

WO2015016253A1 - Separation membrane element

Info

Publication number: WO2015016253A1
Application number: PCT/JP2014/070039
Authority: WO
Inventors: 洋帆広沢; 高木　健太朗; 俊介田林; 由恵丸谷; 宜記岡本; 山田　博之; 修治古野; 佐々木　崇夫; 将弘木村
Original assignee: 東レ株式会社
Priority date: 2013-07-30
Filing date: 2014-07-30
Publication date: 2015-02-05
Also published as: JPWO2015016253A1

Abstract

Provided is a separation membrane element which can exhibit stable separation/removal performance when operated at a high pressure. The separation membrane element is equipped with: a separation membrane which has a feed-side surface and a penetrant-side surface and which has been disposed so that a portion of the penetrant-side surface faces another portion thereof to thereby form a separation membrane pair; and a penetrant-side passage material which has been disposed between the penetrant-side surface portions of the separation membrane and which comprises a sheet having pores and a plurality of projections disposed on the sheet. The projections comprise a resin, and some of the resin has been infiltrated into the sheet. Each width-direction end part of the sheet has a band-shaped region where the projections are absent and, through the band-shaped regions, the penetrant-side surface portions of the separation membrane in the separation membrane pair have been sealed to each other with an adhesive.

Description

Separation membrane element

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

In the technology for removing ionic substances contained in seawater, brine, etc., 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, brackish water and water containing harmful substances, industrial ultrapure water, wastewater treatment and recovery of valuable materials. It is properly used depending on the separation component and separation performance.

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

For example, spiral separation membrane elements are widely used for reverse osmosis filtration. The spiral separation membrane element includes a center tube and a laminate wound around the center tube. The laminated body includes a supply-side channel material that supplies raw water (that is, water to be treated) to the separation membrane surface, a separation membrane that separates components contained in the raw water, and a permeation side that is separated from the supply-side fluid through the separation membrane. It is formed by laminating a permeate-side channel material for guiding fluid to the central tube. 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 water.

In the spiral separation membrane element, generally, a polymer net is mainly used as a supply-side channel material in order to form a supply-side fluid channel. In addition, a stacked type separation membrane is used as the separation membrane. Laminate type separation membranes are laminated from the supply side to the permeate side, a separation functional layer made of a crosslinked polymer such as polyamide, a porous resin layer (porous support layer) made of a polymer such as polysulfone, polyethylene terephthalate, etc. A non-woven substrate made of the above polymer is provided. 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, due to the increasing demand for reducing water production costs, higher performance of separation membrane elements has been demanded. 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, Patent Document 1 proposes a separation membrane element including an unevenly shaped sheet as a permeate-side channel material. In Patent Document 2, a separation membrane that does not require a supply-side channel material such as a net or a permeation-side channel material such as a tricot by a channel material composed of an elastomer called a vane disposed on the separation membrane. Elements have been proposed. Patent Document 3 proposes a separation membrane element provided with a flow path material in which yarns are arranged on a nonwoven fabric.

JP 2006-247453 A Special table 2012-518538 gazette US Patent Application Publication No. 2012-0261333

However, the separation membrane element described above is not sufficient in terms of separation performance, particularly stability performance when operated for a long period of time.
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 under a particularly high pressure.

In order to achieve the above object, the separation membrane element of the present invention comprises a sheet having a porosity of 20% or more and 90% or less, and a permeation-side flow path material composed of a plurality of protrusions having a porosity of 5% or less. Prepare.

According to the present invention, a high-efficiency and stable permeation side flow path can be formed, and a high-performance, high-efficiency separation membrane element having separation component removal performance and high permeation performance can be obtained.

It is a schematic block diagram which shows one form of a membrane leaf. It is a top view which shows the permeation | transmission side channel material provided with the protrusion continuously provided in the length direction (2nd direction) of the sheet | seat. It is a top view which shows the permeation | transmission side channel material provided with the protrusion discontinuously provided in the length direction (2nd direction) of the sheet | seat. It is sectional drawing of the separation membrane of FIG. 2 and FIG. It is a development perspective view showing one form of a separation membrane element. It is a cross-sectional schematic diagram of a separation membrane. It is sectional drawing which shows schematic structure of a separation membrane. It is a partially expanded perspective view which shows the 1st form of a separation membrane element. It is a partially expanded perspective view which shows the 2nd form of a separation membrane element. It is a partially expanded perspective view which shows the 3rd form of a separation membrane element. It is a figure which shows an example of the method of arrange | positioning the permeation | transmission side channel material to a membrane leaf.

Hereinafter, an embodiment of the present invention will be described in detail.
[1. Separation membrane)
(1-1) Outline of Separation Membrane A separation membrane is a membrane that can separate components in the fluid supplied to the surface of the separation membrane and obtain a permeated fluid that has permeated the separation membrane. The separation membrane can also include a membrane in which embossing or resin is arranged so as to form a flow path. In addition, the separation membrane may be one that cannot form a flow path and expresses only a separation function.

As an example of such a separation membrane, an exploded perspective view of a membrane leaf including an example of an embodiment of the separation membrane of the present invention is shown in FIG. In FIG. 1, the membrane leaf 4 includes a plurality of

separation membranes

2a and 2b. The separation membrane 2a has a supply-side surface 21a and a transmission-side surface 22a, and the separation membrane 2b has a supply-side surface 21b and a transmission-side surface 22b. The two separated

separation membranes

2a and 2b are arranged so that the supply-side surface 21a of one separation membrane 2a and the supply-side surface 21b of the other separation membrane 2b face each other. Further, the other separation membrane 2c superimposed thereon is arranged so that the permeation side surface 22c of the separation membrane faces the permeation side surface 22b of the separation membrane 2b below it. 21c is a surface on the supply side of the separation membrane 2c. In this document, the “supply side surface” of the separation membrane means the surface on the side of the separation membrane where raw water is supplied. The “permeate side surface” means the surface on the opposite side from which the permeated fluid that has passed through the separation membrane is discharged. As will be described later, when the separation membrane 2 includes a base material 201, a porous support layer 202, and a separation function layer 203 as shown in FIG. 7, generally, the surface on the separation function layer 203 side is on the supply side. The surface 21 and the surface on the base material 201 side are the surface 22 on the transmission side.

In FIG. 7, the separation membrane 2 is described as a laminate of a base material 201, a porous support layer 202 and a separation functional layer 203. As described above, the surface opened outside the separation functional layer 203 is the supply-side surface 21, and the surface opened outside the base material 201 is the transmission-side surface 22.

FIG. 1, FIG. 2, FIG. 3, FIG. 4, FIG. 5, and FIG. 6 show the x-axis, y-axis, and z-axis direction axes. 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, the separation membrane 2 is rectangular, and the first direction and the second direction are parallel to the outer edge of the separation membrane 2. The first direction may be referred to as the width direction, and the second direction may be referred to as the length direction. In FIG. 1, the first direction (width direction) is represented by a CD arrow, and the second direction (length direction) is represented by an MD arrow.

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

<Separation function layer>
The thickness of the separation functional layer is not limited to a specific numerical value, but is preferably 5 nm or more and 3000 nm or less in terms of separation performance and transmission performance. In particular, in the case of a reverse osmosis membrane, a forward osmosis membrane, and a nanofiltration membrane, the thickness is preferably 5 nm or more and 300 nm or less.

The thickness of the separation functional layer can be in accordance with a normal separation membrane thickness measurement method. 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 observing with a transmission electron microscope. Further, when the separation functional layer has a pleat structure, measurement can be made at intervals of 50 nm in the cross-sectional length direction of the pleat structure located above the porous support layer, the number of pleats can be measured, and the average can be obtained. it can.

The separation function layer may be a layer having both a separation function and a support function, or may have only a separation function. The “separation function 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, polyether sulfone, or polysulfone as a main component is preferably applied as the separation functional layer.

In this specification, “X contains Y as a main component” means that the Y content in X is 50 mass% or more, 70 mass% or more, 80 mass% or more, 90 mass% or more, or It means a case of 95% by mass or more. In addition, when there are a plurality of components corresponding to Y, the total amount of these components only needs to satisfy the above range.

On the other hand, as the separation functional layer supported by the porous support layer, a crosslinked polymer is preferably used in terms of easy control of the pore diameter and excellent durability. In particular, 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 in terms of excellent separation performance of components in raw water. These separation functional layers 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 the 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.

Further, the separation functional layer may have an organic-inorganic hybrid structure containing Si element or the like. The separation functional layer having an organic-inorganic hybrid structure can contain, for example, the following compounds (A) and (B):
(A) a silicon compound in which a reactive group and a hydrolyzable group having an ethylenically unsaturated group are directly bonded to a silicon atom, and (B) a compound other than the compound (A) and having an ethylenically unsaturated group Compound.
Specifically, the separation functional layer may contain a condensate of the hydrolyzable group of the compound (A) and a polymer of the ethylenically unsaturated group of the compounds (A) and / or (B). That is, the separation functional layer is
A polymer formed by condensation and / or polymerization of only the compound (A),
-The polymer formed by superposing | polymerizing only a compound (B), and-At least 1 sort (s) of polymer of the copolymer of a compound (A) and a compound (B) can be contained. The polymer includes a condensate. In the copolymer of compound (A) and compound (B), compound (A) may be condensed via a hydrolyzable group.

The hybrid structure can be formed by a known method. An example of a method for forming a hybrid structure is as follows. A reaction solution containing the compound (A) and the compound (B) is applied to the porous support layer. In order to condense the hydrolyzable group after removing the excess reaction solution, heat treatment may be performed. As a polymerization method of the ethylenically unsaturated groups of the compound (A) and the compound (B), heat treatment, electromagnetic wave irradiation, electron beam irradiation, and plasma irradiation may be performed. For the purpose of increasing the polymerization rate, a polymerization initiator, a polymerization accelerator and the like can be added during the formation of the separation functional layer.
For any separation functional layer, the surface of the membrane may be hydrophilized with an alcohol-containing aqueous solution or an alkaline aqueous solution, for example, before use.

<Porous support layer>
The porous support layer is a layer that supports the separation functional layer, and is also referred to as a porous resin layer.
Although the material used for a porous support layer and its shape are not specifically limited, For example, you may form on a board | substrate with porous resin. As the porous support layer, polysulfone, cellulose acetate, polyvinyl chloride, epoxy resin or a mixture and laminate of them is used, and polysulfone with high chemical, mechanical and thermal stability and easy to control pore size. Is preferably used.

The porous support layer gives mechanical strength to the separation membrane and does not have a separation performance like a separation functional layer for components having a small molecular size such as ions. The pore size and pore distribution of the porous support layer are not particularly limited. For example, the porous support layer may have uniform and fine pores, or the side on which the separation functional layer is formed. It may have a pore size distribution such that the diameter gradually increases from the surface to the other surface (base material side). 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. Particularly 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 preferably have a projected area equivalent circle diameter of 3 nm to 50 nm. .

The thickness of the porous support layer is not particularly limited, but is preferably in the range of 20 μm or more and 500 μm or less, and more preferably 30 μm or more and 300 μm or less for the purpose of giving strength to the separation membrane.

The form of the porous support layer can be observed with a scanning electron microscope, a transmission electron microscope, or an atomic force microscope. For example, when observing with a scanning electron microscope, after peeling off the porous support layer from the substrate, it is cut by the freeze cleaving method to obtain a sample for cross-sectional observation. The sample is thinly coated with platinum, platinum-palladium, or ruthenium tetrachloride, preferably ruthenium tetrachloride, and observed with a high resolution field emission scanning electron microscope (UHR-FE-SEM) at an acceleration voltage of 3 kV to 6 kV. As the high-resolution field emission scanning electron microscope, Hitachi S-900 electron microscope can be used. Based on the obtained electron micrograph, the film thickness of the porous support layer and the projected area equivalent circle diameter of the surface can be measured.

The 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 perpendicular to the thickness direction by cross-sectional observation, and is an average value of 20 point measurements. 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. For example, a porous support layer is formed by casting a solution of polysulfone in N, N-dimethylformamide (hereinafter referred to as DMF) on a substrate to be described later, for example, a densely woven polyester cloth or non-woven cloth to a constant thickness. And can be produced by wet coagulation in water.

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

For example, a predetermined amount of polysulfone is dissolved in DMF to prepare a polysulfone resin solution having a predetermined concentration. Next, this polysulfone resin solution is applied to a substrate made of polyester cloth or nonwoven fabric to a substantially constant thickness, and after removing the surface solvent in the air for a certain period of time, the polysulfone is coagulated in the coagulation liquid. A porous support layer can be obtained.

<Base material>
From the viewpoint of the strength and dimensional stability of the separation membrane, the separation membrane can have a substrate. As the base material, it is preferable to use a fibrous base material in terms of strength, unevenness forming ability and fluid permeability.
As a base material, both a long fiber nonwoven fabric and a short fiber nonwoven fabric can be used preferably. In particular, since the long fiber nonwoven fabric has excellent film-forming properties, when the polymer solution is cast, the solution penetrates through the permeation, the porous support layer peels off, and Can suppress the film from becoming non-uniform due to fluffing of the substrate and the like, and the occurrence of defects such as pinholes. In addition, since the base material is made of a long-fiber nonwoven fabric composed of thermoplastic continuous filaments, compared to a short-fiber nonwoven fabric, non-uniform film formation and film defects caused by fiber fluffing during polymer solution casting 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 non-woven fabric, the fibers in the surface layer on the side opposite to the porous support layer are preferably longitudinally oriented compared to the fibers in the surface layer on the porous support layer side in terms of moldability and strength. According to such a structure, not only a high effect of preventing membrane breakage by maintaining strength is realized, but also a laminate comprising a porous support layer and a substrate when imparting irregularities to the separation membrane The moldability is improved, and the uneven shape on the surface of the separation membrane is stabilized, which is preferable.

More specifically, the fiber orientation degree in the surface layer on the side 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 in the surface layer on the porous support layer side. The degree of orientation difference with respect to the degree is preferably 10 ° or more and 90 ° or less.

The heating process is included in the manufacturing process of the separation membrane and the manufacturing process of the separation membrane element, but the phenomenon that the porous support layer or the separation functional layer contracts due to the heating occurs. In particular, the shrinkage is remarkable 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. Can also be preferred.

Here, the fiber orientation degree is an index indicating the direction of the fibers of the nonwoven fabric base material constituting the porous support layer. Specifically, the fiber orientation degree is an average value of angles between the film forming direction when continuous film forming is performed, that is, the longitudinal direction of the nonwoven fabric base material and the longitudinal direction of the fibers constituting the nonwoven fabric base material. is there. 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 °. Accordingly, the closer to 0 ° the fiber orientation, the longer the orientation, and the closer to 90 °, the lateral orientation.

The fiber orientation degree 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 fibers are selected for each sample, and the angle of the fibers in the longitudinal direction when the longitudinal direction of the nonwoven fabric is 0 ° is measured. Here, the longitudinal direction of the nonwoven fabric refers to “Machine direction” at the time of manufacturing the nonwoven fabric. The longitudinal direction of the nonwoven fabric coincides with the film forming direction of the porous support layer and the MD direction in FIGS. The CD direction in FIGS. 1 and 5 corresponds to “Cross direction” at the time of manufacturing the nonwoven fabric.

Thus, the angle is measured for a total of 100 fibers per nonwoven fabric. For the 100 fibers thus measured, an average value is calculated from the angle in the longitudinal direction. The value obtained by rounding off the first decimal place of the obtained average value is the fiber orientation degree.

It is preferable that the thickness of the base material is selected so that the total thickness of the base material and the porous support layer is in the range of 30 μm to 300 μm, or in the range of 50 μm to 250 μm.

(1-3) Permeation side channel material <Overview>
The permeation side channel material of the present invention is composed of a sheet having a porosity of 20% or more and 90% or less and a plurality of protrusions having a porosity of 5% or less, and the plurality of protrusions are formed integrally with the sheet. Has been. By having such a configuration for the permeation-side channel material, the permeation-side flow resistance can be reduced, and high channel stability can be achieved at the same time. Specifically, when the porosity of the sheet and the plurality of protrusions is within the above range, the flow resistance of the groove formed by the space of the sheet and the plurality of protrusions can be reduced. In addition, for the convenience of the formation process of the permeate-side channel material, even when the projection is not sufficiently arranged and the groove is closed, the gap of the sheet becomes the channel and the permeate passes through the sheet. Can move to another groove.

The permeate-side channel material of the present invention is disposed on the permeate-side surface 22 of the membrane leaf 4 as shown in FIG. At this time, whether the projection touches the transmission side surface 22 or the sheet contacts the transmission side surface 22 depends on whether the membrane leaf 4 is wrapped or laminated, Since a protrusion and a sheet | seat contact and it will be in the same state after all, it will not specifically limit. The details of the configuration of the permeate-side channel material are as follows.

<Strip end>
In FIG. 4, the sheet 302 in the permeate-side flow path member 31 is provided with a band-like region 303 where the protrusions 301 are not disposed at the end thereof. This strip region 303 is referred to as a strip end.
The band-shaped end portion is a portion where the protrusions 301 are not provided on the sheet 302. Thus, the permeation side surface of one separation membrane and the permeation side surface of the other separation membrane are bonded together through such a band-like region 303. Through the band-like region 303, the penetration of the leaf adhesive due to the protrusions does not occur, and uneven application of the leaf adhesive and poor adhesion can be eliminated and the sealing performance between the separation membranes can be improved.

The width of the band-shaped end portion can be determined according to the separation membrane element size, the operating pressure, the thickness of the permeate-side channel material, and the amount of leaf adhesive applied, but is wider than the groove width (CD direction) formed by the protrusion 301 It is better, and it can be appropriately changed, particularly in the range of 0.25 mm to 70 mm. Within this range, good sealing performance can be obtained even if a permeate-side channel material with protrusions fixed to the sheet is used, and the effective membrane area of the separation membrane with leaf adhesive (loaded in the separation membrane element) Among the separated membranes, it is possible to prevent a decrease in the total area of the separation membrane that exhibits the separation function.

<The sheet | seat which comprises a permeation | transmission side channel material>
In the separation membrane element, the sheet 302 constituting the permeate-side flow path member is preferably arranged so that the second direction coincides with the winding direction as shown in FIG. That is, in the separation membrane element of FIGS. 8, 9 and 10, the sheet 302 has a first direction (width direction of the separation membrane) parallel to the longitudinal direction of the water collecting pipe 6 and a second direction (length of the separation membrane). (Direction) is preferably arranged so as to be orthogonal to the longitudinal direction of the water collecting pipe 6.

Further, the sheet constituting the permeation side channel material exists in a region where the permeation side surfaces of the separation membrane are bonded to each other. That is, it is preferable that the two separation membranes are bonded to each other with the sheet constituting the permeation side flow path member interposed therebetween, and the sheet exists between the separation membranes in at least a part of the bonded portion. In FIG. 11, the size of the sheet 302 constituting the permeate-side flow path material and the size of the separation membrane are the same, but actually the sheet may be larger or the separation membrane may be larger. Good. When the separation membrane is larger, the sheet becomes a wall, so that the spread of the adhesive can be suppressed.

(Thickness unevenness of the sheet constituting the permeate side channel material)
The thickness unevenness of the sheet 302 constituting the permeate-side channel material is preferably 0.03 mm or less, and more preferably 0.02 mm or less. As the thickness spots are larger, the spread of the leaf adhesive tends to be larger, and the effective film area and the sealing performance as described above are lowered. The thickness unevenness of the sheet can be measured using a commercially available thickness meter (for example, Mitsutoyo Thickness Gauge Part No. 547-401, Keyence Digital Microscope Model No. VHX-1100). The thickness can be measured for the position, and the difference between the maximum value and the minimum value can be regarded as a thickness spot.

(Porosity of the sheet constituting the permeate side channel material)
The porosity of the sheet 302 constituting the permeate-side channel material is preferably 20% or more and 90% or less, and particularly preferably 45% or more and 80% or less. Here, the porosity means the ratio of the voids per unit volume of the substrate, and the weight when the substrate is dried is subtracted from the weight when pure water is included in the substrate having a predetermined apparent volume. The value obtained by dividing the obtained value by the apparent volume of the substrate is expressed as a percentage (%).

When the porosity of the sheet 302 exceeds 90%, the flow resistance is lowered, but the impregnation of the protrusions 301 is easy to proceed, and the back-through occurs, and the thickness of the sheet 302 becomes uneven. In addition, the adhesive that bonds the leaves easily spreads, and the area where the adhesive is not applied after formation of the separation membrane element, that is, the area where effective pressure filtration functions effectively (effective membrane area) is reduced. The amount of water produced is reduced. On the other hand, when the porosity of the sheet 302 is less than 20%, the impregnation of the protrusions 301 and the adhesive hardly progresses, and the protrusions 301 are peeled off from the sheet 302 and a flow path cannot be formed. Since the impregnation tends to be insufficient, the supply water flows into the permeate-side flow path and the separation performance deteriorates. Furthermore, the permeated water is difficult to permeate the sheet 302, and the permeated water does not reach the grooves between the protrusions 301 or the flow path in the sheet 302. As a result, the amount of water produced by the separation membrane element is greatly reduced.

<Thickness H1 of the sheet constituting the permeate side channel material>
It is preferable that the thickness of the sheet | seat which comprises a permeation | transmission side channel material is 0.2 mm or less. This is because the sheet is preferably impregnated with an adhesive in order to seal between the permeation side surfaces of the two separation membranes. However, even if the thickness of the sheet constituting the permeate-side channel material exceeds 0.2 mm, the separation membrane can be sealed with an adhesive as long as the porosity of the sheet is 80% or more. Moreover, since the strength of the sheet can be ensured when the thickness of the sheet constituting the permeate-side flow path material is 0.02 mm or more, damage to the sheet can be suppressed.

In particular, if the thickness of the sheet constituting the permeate-side channel material 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 exceeds 0.02 mm. If it is 0.4 mm or less, the porosity is more preferably 30% or more and 90% or less.

The relationship between the height c (described later) of the protrusion and the thickness H1 of the sheet will be described. The ratio (c / H0) of the projection height c to the sum H0 (H0 = H1 + c) of the sheet thickness H1 and the projection height c is preferably 0.05 or more. This is because a wide flow path can be secured. On the other hand, it is preferable that the ratio (c / H0) is 0.7 or less because the sheet can be prevented from being broken or damaged by the protrusions when the sheet is wound while applying a tension. 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.

<Protrusions>
(Porosity of protrusion 301)
On the other hand, the porosity of the protrusions 301 (see paragraph 0049) is preferably 5% or less, and more preferably 2% or less. The pressure is concentrated on the protrusion 301 during pressure filtration or winding of the sheet. If the protrusion 301 is deformed, the groove formed by the plurality of protrusions 301 serving as the flow path becomes narrow, and thus the flow resistance increases. However, when the porosity is 5% or less, the protrusions are not easily deformed even during compression.

<Constituent components of protrusion>
The material constituting the permeate-side channel material, that is, the component constituting the sheet and the projection is not limited to a specific substance, but a resin is preferably used. Specifically, in view of chemical resistance, ethylene vinyl acetate copolymer resin, polyolefin such as polyethylene and polypropylene, and polyolefin copolymer are preferable. In addition, the material of the permeate side channel material is urethane resin, epoxy resin, polyethersulfone, polyacrylonitrile, polyvinyl chloride, polyvinylidene chloride, polyvinyl alcohol, ethylene-vinyl alcohol copolymer, polystyrene, styrene-acrylonitrile copolymer Polymer, styrene-butadiene-acrylonitrile copolymer, polyacetal, polymethyl methacrylate, methacryl-styrene copolymer, cellulose acetate, polycarbonate, polyethylene terephthalate, polybutadiene terephthalate and fluororesin (ethylene trifluoride chloride, polyvinylidene fluoride, tetrafluoride) Ethylene, tetrafluoroethylene-hexafluoropropylene copolymer, tetrafluoroethylene-perfluoroalkoxyethylene copolymer, tetrafluoroethylene-ethylene copolymer Etc.) can also be selected polymers such as. These materials are used alone or as a mixture of two or more. In particular, since the thermoplastic resin is easy to mold, it is possible to form a permeate-side channel material having a uniform shape, and the sheet and the protrusion may be the same material or different materials.

A composite material can also be applied as the material of the permeate side channel material. Examples of the composite material include a material containing the above-described resin as a base material and further containing a filler. The compression elastic modulus of the permeate side channel material can be increased by adding a filler such as a porous inorganic material to the base material. Specifically, alkaline earth metal silicates such as sodium silicate, calcium silicate and magnesium silicate, metal oxides such as silica, alumina and titanium oxide, and alkaline earth metals such as calcium carbonate and magnesium carbonate. Carbonate, pure meteorite, meteorite powder, caustic clay, wollastonite, sepiolite, attapulgite, kaolin, clay, bentonite, gypsum, talc, etc. can be used as fillers. In addition, the addition amount of a filler will not be specifically limited if it is a range which does not impair the effect of this invention.

<< Permeation side channel material composed of polypropylene >>
Moreover, when the permeation | transmission side channel material takes the following structures, the balance of a pressure resistance and a softness | flexibility can be made compatible and driving | operation stability can be improved. That is, the permeate side channel material may contain highly crystalline polypropylene and may satisfy the following requirements (a) and (b).
(A) The content of the highly crystalline polypropylene is 40 to 95% by weight in the composition constituting the permeation side channel material.
(B) The melting endotherm (ΔH) of the channel material is 20 to 70 J / g.
In this case, curling of the separation membrane in which the permeation side flow path is formed can be suppressed by setting the content of the highly crystalline polypropylene to 95% by weight or less in the composition constituting the permeation side flow path material. Thereby, the handling property of the separation membrane is improved, and the permeability in the step of laminating the envelope membrane, which is one of the manufacturing steps of the separation membrane element, is remarkably improved. The content of the highly crystalline polypropylene is more preferably 85% by weight or less, and further preferably 75% by weight or less.

On the other hand, by setting the content of the high crystalline polypropylene to 40% by weight or more in the composition constituting the permeation side flow path material, not only the curling of the separation membrane is improved, but also, for example, the separation membrane of the present invention Even if the element is operated under a pressure condition exceeding 2 MPa, it is possible to suppress the compressive deformation of the permeate-side channel material, and as a result, it is possible to suppress a decrease in the separation membrane element performance (particularly water production performance) and to be stable. Performance can be expressed. From the viewpoint of suppressing the amount of compressive deformation, the content of the highly crystalline polypropylene is more preferably 45% by weight or more, and further preferably 50% by weight.

Examples of the highly crystalline polypropylene include propylene homopolymer; propylene random copolymer; propylene block copolymer, and the like. These may be used alone or in combination of two or more. The melting point of the highly crystalline polypropylene is preferably 140 ° C. or higher, and more preferably 150 ° C. or higher. The melting point is a value measured with a differential scanning calorimeter (DSC). For example, a sample is evaluated using a thermal analyzer such as a thermomechanical analyzer TMA / SS-6000 manufactured by Seiko Instruments Inc. under the conditions of probe: penetration probe, measurement load: 10 g, temperature increase rate: 5 ° C./min. The melting point can be measured.

Furthermore, the melt flow rate (MFR) of the highly crystalline polypropylene is preferably 10 to 2000 g / 10 minutes. By setting the MFR in such a range, it is easy to melt-mold the permeate-side channel material. It is also possible to set the melt molding temperature low. As a result, it is possible to suppress damage to the separation membrane body due to heat and degradation of the separation membrane performance during melt molding, and to adhere to the permeate side surface of the separation membrane body. Property is improved. The MFR of the highly crystalline polypropylene is more preferably 30 to 1800 g / 10 min, and further preferably 50 to 1500 g / min. The MFR is a value measured under conditions of 230 ° C. and a load of 2.16 kg in accordance with JIS-K7200 (1999).

The melting endotherm (ΔH) of the permeate-side channel material is preferably 20 to 70 J / g. When ΔH of the permeate-side channel material is smaller than 20 J / g, curling of the separation membrane is sufficiently suppressed, but on the other hand, crystallization of the composition constituting the permeate-side channel material becomes very slow, The side channel material becomes sticky. As a result, at the time of roll conveyance, the permeate side channel material adheres to the roll, or the permeate side channel material is deformed by contact with the roll. Furthermore, when the film is wound up by a winder and then unwound, the permeate-side flow path material adheres to the separation functional layer side of the separation membrane, and the unwinding property of the separation membrane roll is significantly deteriorated. Membrane handling is greatly reduced. Furthermore, the amount of compressive deformation under pressure operation increases.

On the other hand, when ΔH of the permeate side channel material is larger than 70 J / g, the composition of the permeate side channel material is rapidly crystallized. The amount of volume change accompanying the cooling and solidification of the composition is very large. As a result, the separation membrane is greatly curled. Furthermore, the permeate side channel material becomes very fragile, and the permeate side channel material is broken during roll conveyance.

The ΔH of the permeate-side channel material is more preferably 25 to 65 J / g, and further preferably 30 to 60 J / g. The melting endotherm is a numerical value measured with a differential scanning calorimeter (DSC). For example, measurement was performed using a differential scanning calorimeter DSC-7 manufactured by PerkinElmer, Inc., and a 10 mg sample was heated from 20 ° C. to 220 ° C. at a heating rate of 10 ° C./min and held at 220 ° C. for 10 minutes. Thereafter, in the measurement of lowering the temperature to 20 ° C. at a temperature lowering rate of 10 ° C./min, the calorific value based on crystallization observed when the temperature is lowered can be obtained.

Further, the composition constituting the permeation side flow path member preferably contains a low crystalline α-olefin polymer, and the content thereof is 5 to 60% by weight in the composition constituting the permeation side flow path material. % Is preferred.

The low crystalline α-olefin polymer of the present invention is an amorphous or low crystalline α-olefin polymer. For example, the low crystalline polypropylene such as atactic polypropylene or isotactic polypropylene having low stereoregularity. An ethylene / α-olefin copolymer selected from the group consisting of ethylene and an α-olefin having 3 to 20 carbon atoms (the α-olefin having 3 to 20 carbon atoms includes linear and branched α-olefins). Specifically, as the linear α-olefin, propylene, 1-butene, 1-pentene, 1-hexene, 1-heptene, 1-octene, 1-nonene, 1-decene, 1-undecene, 1-dodecene, 1-tridecene, 1-tetradecene, 1-pentadecene, 1-hexadecene, 1-heptadecene, 1-octade , 1-nonadecene, 1-eicosene and the like. Examples of the branched α-olefin include 3-methyl-1-butene, 3-methyl-1-pentene, 4-methyl-1-pentene, 2-ethyl 1-hexene, 2,2,4-trimethyl-1-pentene, etc.); (B-3) Commercially available products such as “Tuffmer” manufactured by Mitsui Chemicals, Inc. and “Tufselen” manufactured by Sumitomo Chemical Co., Ltd. Examples include propylene / olefin copolymers. In the present invention, one or more of these can be used. Among them, the low crystalline α-olefin polymer (B) includes low crystalline polypropylene and propylene / olefin copolymer from the viewpoints of good compatibility with high crystalline polypropylene, versatility, and curling improvement effect of the separation membrane. A polymer is more preferred.

In the present embodiment, the content of the low crystalline α-olefin-based polymer (B) is preferably 5 to 60% by weight with respect to the composition constituting the permeation side flow path material. By setting the content of the low crystalline α-olefin polymer to 5% by weight or more, flexibility can be imparted to the permeate-side channel material, and the crystallization speed of the high crystalline polypropylene can be delayed. As a result, curling of the separation membrane can be suppressed. On the other hand, if the content of the low crystalline α-olefin polymer exceeds 60% by weight, the curl of the separation membrane can be greatly improved, but the flexibility of the permeate side channel material becomes remarkably high, for example exceeding 2 MPa. When operated under pressurized conditions, the amount of compressive deformation of the permeate-side channel material increases, and as a result, the separation membrane element performance (particularly water production performance) is greatly reduced due to channel blockage. The content of the low crystalline α-olefin polymer is more preferably 10 to 55% by weight, more preferably 15 to 50% by weight, from the viewpoint of flexibility of the permeation side channel material and compressive deformation under pressure. More preferably it is.

Further, in the present invention, the permeate-side channel material fixed to the permeate-side surface of the separation membrane main body is an additive such as a thermal fluidity improver, a filler, an antioxidant, a lubricant, etc., as long as the object of the invention is not impaired. 1 type or 2 types or more may be included.

Examples of the thermal fluidity improver include synthetic waxes such as polyethylene wax, polypropylene wax, atactic polypropylene wax, Fischer-Tropsch wax; petroleum waxes such as paraffin wax and microwax; natural waxes such as carnauba wax and beeswax; rosin, Rosin resins such as hydrogenated rosin, polymerized rosin, and rosin ester; Terpene resins such as terpenes, hydrogenated terpenes, aromatic modified terpenes, and aromatic modified hydrogenated terpenes; “Imabe” manufactured by Idemitsu Kosan Examples include hydrogenated petroleum resins such as “Alcon” (trade name) manufactured by Arakawa Chemical Industries, Ltd., “Petocol”, “Petrotac” (all trade names) manufactured by Tosoh Corporation, and the like, but are not limited thereto. Moreover, you may use these individually or in mixture of 2 or more types. Of these, synthetic waxes, terpene resins, and hydrogenated petroleum resins are preferred from the viewpoint of the effect of improving the thermal fluidity of the composition, the compatibility with highly crystalline polypropylene, and the heat decomposability of the composition during heating and melting. In addition, the content can be appropriately set in order to adjust the melt viscosity of the composition constituting the permeate-side flow path material, but it may cause a decrease in pressure resistance of the permeate-side flow path material and the occurrence of bleed out on the surface of the flow path material. In consideration of prevention, it is preferably 50% by weight or less, more preferably 40% by weight or less, in the composition constituting the permeation side channel material.

Examples of the antioxidant include, but are not limited to, phenolic compounds; phosphorus compounds; hindered amine compounds; sulfur compounds. Moreover, you may use these individually or in mixture of 2 or more types. The content is preferably 0.001 to 1% by weight with respect to the composition constituting the permeate-side channel material from the viewpoint of suppressing thermal decomposition of the composition at the time of forming the permeate-side channel material. .

As the lubricant, fatty acid amide compounds such as stearamide, oleic acid amide, erucic acid amide, ethylene bis stearic acid amide; metal soaps such as calcium stearate, zinc stearate, magnesium stearate, zinc stearate; fatty acid ester Although a compound etc. can be illustrated, it is not limited to these. Moreover, you may use these individually or in mixture of 2 or more types.

Examples of fillers include, but are not limited to, inorganic compounds such as calcium carbonate, talc, alumina, silica, mica, and clay. These may be used alone or in admixture of two or more. From the viewpoint of moldability of the permeate side channel material, thickening of the composition, and wear of the processing apparatus, the content is 3 to 30% by weight with respect to the composition constituting the permeate side channel material. preferable.

In this embodiment, it is preferable that the tensile elongation of the permeate-side channel material fixed to the permeate-side surface of the separation membrane body is 5% or more. If the tensile elongation is 5% or more, even if the separation membrane is rolled or wound on a winder, the flow channel material can be prevented from being damaged or broken, and a high-quality separation membrane can be obtained. In the element manufacturing process, handleability is improved. The tensile elongation is more preferably 7% or more, still more preferably 10% or more. In addition, the higher the tensile elongation, the higher the energy required for fracture, which is preferable from the viewpoint of toughness. However, if the tensile elongation is excessively high, the amount of deformation under a constant stress increases, so 300% or less is preferable. 200% or less is more preferable.

In this embodiment, it is preferable that the tensile elastic modulus of the permeate-side channel material fixed to the permeate-side surface of the separation membrane main body is 0.2 to 2.0 GPa. By setting the tensile modulus to 0.2 GPa or more, even when the separation membrane element is operated under a pressure condition exceeding 2.0 MPa, the amount of compressive deformation of the flow path material can be suppressed. A decrease in performance can be suppressed. The tensile elastic modulus is more preferably 0.25 GPa or more, and further preferably 0.30 GPa or more. The higher the tensile elastic modulus, the more the amount of compressive deformation of the channel material during the pressurizing operation can be suppressed, but it is difficult to substantially achieve 2.0 GPa or more.

<Shape and arrangement of protrusions>
<< Overview >>
A tricot that has been widely used in the past is a knitted fabric, and is composed of three-dimensionally intersecting yarns. That is, the tricot has a two-dimensionally 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, it is a structure with many ratios which do not become a groove.

On the other hand, as an example of the configuration of the present invention, a protrusion 301 shown in FIG. 2 and the like is arranged on a sheet 302 having a gap. Therefore, the height (that is, the thickness) of the protrusion 301 of the present embodiment can be used as the height of the groove of the flow path, and the sheet 302 can be used as the flow path because it has a gap. Therefore, the flow resistance (the groove between the protrusions 301 and the gap in the sheet 302) is wider than when a tricot having the same thickness as the flow path material of the present embodiment is applied, so that the flow resistance is more Get smaller.

Moreover, in the form shown in each drawing, a plurality of discontinuous protrusions 301 are fixed on one sheet 302. “Discontinuous” is a state in which a plurality of flow path members are provided at intervals. That is, when one protrusion 301 is peeled from the sheet 302, a plurality of protrusions 301 separated from each other are obtained. On the other hand, members such as nets, tricots, and films exhibit a continuous and integral shape even when the flow path is separated from the sheet 302.

Since the plurality of discontinuous protrusions 301 are provided, the separation membrane 2 can suppress pressure loss when it is incorporated into the separation membrane element 100 described later. As an example of such a configuration, in FIG. 2, the protrusions 301 are formed discontinuously only in the first direction (the width direction of the sheet 302), and in FIG. 3, the first direction (the width direction of the sheet 302) and the first It is formed discontinuously in any of the two directions (the length direction of the separation membrane).

2 and 3, the permeate-side flow path 5 is formed in the space between the adjacent protrusions 301.
In the form shown in FIG. 2, the permeation-side channel material 31 is provided discontinuously in the first direction and is provided so as to continue from one end of the sheet 302 to the other end in the second direction. That is, when the sheet 302 is incorporated into the separation membrane element as shown in FIG. 5, the protrusions 301 are arranged so as to continue from the inner end to the outer end of the sheet 302 in the winding direction. The inner side in the winding direction is the side close to the water collecting pipe 6 in the separation membrane, and the outer side in the winding direction is the side far from the water collecting pipe 6 in the separation membrane.

The passage material is “continuous in the second direction” means that the passage material is provided without interruption as shown in FIG. 2 and the passage material is interrupted as shown in FIG. It includes both cases where the channel material is substantially continuous. In the “substantially continuous” form, preferably, as shown in FIG. 3, the distance e between the flow path members in the second direction (that is, the length of the discontinuous portion in the flow path material) is 5 mm or less. Satisfy that. In particular, the distance e is more preferably 1 mm or less, and further preferably 0.5 mm or less. In addition, the total value of the intervals e included from the beginning to the end of the line of flow path materials arranged in the second direction is preferably 100 mm or less, more preferably 30 mm or less, and more preferably 3 mm or less. Further preferred. In the form of FIG. 2, the interval e is 0 (zero).

When the protrusions 301 are provided without interruption in the second direction as shown in FIG. 2, membrane dropping is suppressed during pressure filtration. Membrane sagging is that the membrane falls into the channel and narrows the channel.

In FIG. 3, the protrusions 301 are discontinuously provided not only in the first direction but also in the second direction. That is, the protrusions 301 are provided at intervals in the length direction. However, as described above, the protrusions 301 are substantially continuous in the second direction, so that film sagging is suppressed. However, by providing the discontinuous protrusions 301 in the two directions as described above, the contact area between the 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 projections 301 and the sheet 302 while flowing through the permeation side flow path 5, and can be further merged downstream.

As described above, in FIG. 2, the protrusions 301 are provided so as to be continuous from one end to the other end of the sheet 302 in the second direction. In FIG. 3, the protrusion 301 is divided into a plurality of portions in the second direction, but the plurality of portions are provided so as to be arranged from one end to the other end of the sheet 302.

The passage material is “provided from one end of the sheet to the other end” means that the protrusion 301 is provided to the edge of the sheet 302 and the region where the protrusion 301 is not provided in the vicinity of the edge. Includes both forms. In other words, the protrusions 301 need only be distributed in the second direction to such an extent that a passage on the transmission side can be formed, and the sheet 302 may have a portion where the protrusions 301 are not provided. For example, the protrusion 301 does not need to be provided in a portion (in other words, a contact portion) bonded to the separation membrane on the transmission side surface. In addition, for other specifications or manufacturing reasons, a region where the protrusions 301 are not disposed may be provided at some locations such as the end of the separation membrane.

Also in the first direction, the protrusions 301 can be distributed almost uniformly over the entire sheet 302. However, similarly to the distribution in the second direction, the protrusions 301 do not need to be provided at the bonding portion of the permeate side surface with the separation membrane. Further, for other specifications or manufacturing reasons, an area where the protrusions 301 are not arranged may be provided in some places such as the end of the sheet 302.

<< Dimension of protrusion >>
2 to 4, a to f indicate the following values.
a: Length of the separation membrane 2 b: Distance between the projections 301 in the width direction of the separation membrane 2 c: Height of the projections (height difference between the projections 301 and the surface 22 on the transmission side of the sheet)
d: Width of the protrusion 301 e: Distance between the protrusions in the length direction of the separation membrane 2 f: Length of the protrusion 301

For measurement of the values a, b, c, d, e, f, for example, a commercially available shape measuring system or a microscope can be used. Each value is obtained by performing measurement at 30 or more locations on one separation membrane, and calculating an average value by dividing the sum of these values by the number of measurement total locations. Thus, each value obtained as a result of the measurement at at least 30 locations should satisfy the range described below.

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

(Distance b between the protrusions 301 in the width direction of the separation membrane)
The interval b between the protrusions 301 adjacent in the first direction (the width direction of the separation membrane) corresponds to the width of the permeation side flow path 5. When the width of one permeation side flow path 5 is not constant in one cross section, that is, when the side surfaces of two adjacent projections 301 are not parallel, the width of one permeation side flow path 5 is within one cross section. Measure the average value of the maximum and minimum values and calculate the average value. As shown in FIG. 4, in the cross section perpendicular to the second direction, when the protrusion 301 has a trapezoidal shape with a thin top and a thick bottom, first, the distance between the upper portions of the two adjacent protrusions 301 and the lower portion The distance is measured and the average value is calculated. The distance between two adjacent protrusions 301 is measured at any 30 or more cross sections, and an average value is calculated for each cross section. And the space | interval b is calculated by calculating further the arithmetic mean value of the average value obtained in this way.

As the distance b increases, the pressure loss decreases, but the film falls easily. Conversely, the smaller the distance b, the less likely the film will drop, but the greater the pressure loss. Considering the pressure loss, the interval b is preferably 0.05 mm or more, 0.2 mm or more, or 0.3 mm or more. Further, in terms of suppressing film sagging, the interval b is preferably 5 mm or less, 3 mm or less, 2 mm or less, or 0.8 mm or less.

These upper and lower limits can be combined arbitrarily. For example, the interval b is preferably 0.05 mm or more and 5 mm or less, and within this range, the pressure loss can be reduced while suppressing film sagging. The distance b is more preferably 0.05 mm or more and 3 mm or less, 0.2 mm or more and 2 mm or less, and further preferably 0.3 mm or more and 0.8 mm or less.

(Projection height c)
The height c is a height difference between the protrusion and the surface of the sheet 302. As shown in FIG. 4, the height c is a difference in height between the highest portion of the protrusion 301 and the transmission side surface of the sheet 302 in a cross section perpendicular to the second direction. That is, the thickness of the portion impregnated in the base material is not considered as the height of the protrusion. The height c is a value obtained by measuring the heights of 30 or more protrusions 301 and averaging them. The height c of the protrusion may be obtained by observing the cross section of the flow path material in the same plane, or may be obtained by observing the cross sections of the flow path material in a plurality of planes.

The height c can be appropriately selected according to the use conditions and purpose of the separation membrane element, but may be set as follows, for example.
The larger the height c, the smaller the flow resistance. Therefore, the height c is preferably 0.03 mm or more, 0.05 mm or more, or 0.1 mm or more. On the other hand, the smaller the height c, the larger the number of membranes filled per separation membrane element. Therefore, the height c is preferably 0.8 mm or less, 0.4 mm or less, or 0.32 mm or less. These upper and lower limits can be combined. For example, the height c is preferably 0.03 mm to 0.8 mm (30 μm to 800 μm), and preferably 0.05 mm to 0.4 mm. Preferably, it is 0.1 mm or more and 0.32 mm or less.

Moreover, it is preferable that the difference in height between two adjacent channel materials is small. If the difference in height is large, the separation membrane is distorted during pressure filtration, so that defects may occur in the separation membrane. The difference in height between two adjacent channel materials is preferably 0.1 mm or less (100 μm or less), more preferably 0.06 mm or less, and further preferably 0.04 mm or less.
For the same reason, the maximum height difference of all the protrusions 301 provided on the sheet 302 is preferably 0.25 mm or less, particularly preferably 0.1 mm or less, and further preferably 0.03 mm or less. .

(Width d of the channel material)
The width d of the protrusion 301 is measured as follows. First, in one section perpendicular to the first direction (the width direction of the separation membrane), the average value of the maximum width and the minimum width of one protrusion 301 is calculated. That is, in the protrusion 301 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 flow path material are measured, and the average value is calculated. By calculating such an average value in at least 30 cross-sections and calculating the arithmetic average thereof, the width d per film can be calculated.

The width d of the protrusion 301 is preferably 0.2 mm or more, and more preferably 0.3 mm or more. When the width d is 0.2 mm or more, the shape of the flow path material can be maintained even when pressure is applied to the projections 301 and the sheet 302 during operation of the separation membrane element, and the permeate-side flow path is stable. It is formed. The width d is preferably 2 mm or less, and more preferably 1.5 mm or less. When the width d is 2 mm or less, a sufficient flow path on the permeate side can be secured.

Since the width d of the protrusions 301 is wider than the interval b of the protrusions 301 in the second direction, the pressure applied to the flow path material can be dispersed.
The protrusion 301 is formed so that its length is larger than its width. Such a long protrusion 301 is also referred to as a “wall-like object”.

(Protrusion spacing e in the length direction of the separation membrane)
The distance e between the protrusions 301 in the second direction (length direction of the separation membrane) is the shortest distance between the protrusions 301 adjacent in the second direction (length direction of the separation film). As shown in FIG. 2, the protrusions 301 are continuously provided from one end to the other end of the separation membrane 2 in the second direction (in the separation membrane element, from the inner end to the outer end in the winding direction). If there is, the interval e is 0 mm. Moreover, as shown in FIG. 3, when the protrusion 301 is interrupted in the second direction, the interval e is preferably 5 mm or less, more preferably 1 mm or less, and further preferably 0.5 mm or less. . When the distance e is within the above range, the mechanical load on the film is small even when the film is dropped, and the pressure loss due to the blockage of the flow path can be relatively small. In addition, the minimum of the space | interval e is 0 mm.

(Projection length f)
The length f of the protrusion 301 is the length of the protrusion 301 in the length direction of the separation membrane 2 (that is, the second direction). The length f is obtained by measuring the length of 30 or more protrusions 301 in one separation membrane 2 and calculating an average value thereof. The length f of the protrusion 301 may be equal to or less than the length a of the separation membrane. When the length f of the protrusion 301 is equal to the length a of the separation membrane, it means that the protrusion 301 is continuously provided from the inner end to the outer end in the winding direction of the separation membrane 2. The length f is preferably 10 mm or more, more preferably 20 mm or more. Since the length f is 10 mm or more, the flow path is secured even under pressure.

(Shape of protrusion)
The shape of the protrusion 301 is not particularly limited, but a shape that reduces the flow resistance of the channel and stabilizes the channel when permeated can be selected. In these respects, the shape of the protrusion 301 in any cross section perpendicular to the surface direction of the separation membrane may be a straight column shape, a trapezoidal shape, a curved column shape, or a combination thereof.

When the protrusion 301 has a trapezoidal cross-sectional shape, if the difference between the length of the upper base and the length of the lower base is too large, the membrane that contacts the smaller side is likely to drop during pressure filtration. For example, when the upper base of the channel material is shorter than the lower base, the upper width of the channel between them is wider than the lower width. Therefore, the upper film tends to drop downward. Therefore, in order to suppress such a drop, the ratio of the length of the upper base to the length of the lower base of the flow path material is preferably 0.6 or more and 1.4 or less, and is 0.8 or more and 1.2 or less. Further preferred.

From the viewpoint of reducing flow resistance, the shape of the protrusion 301 is preferably a straight column shape perpendicular to the later-described separation membrane surface. Further, the protrusion 301 may be formed so that the width becomes smaller at a higher part, or conversely, the protrusion 301 may be formed so that the width becomes wider at a higher part, or the height from the surface of the separation membrane. Regardless, it may be formed to have the same width.
However, the upper side of the projection 301 may be rounded in the cross section of the protrusion 301 as long as the flow path material is not significantly crushed during pressure filtration.

The protrusion 301 can be formed of a thermoplastic resin. If the projection 301 is a thermoplastic resin, the shape of the flow path material can be freely changed so that the required separation characteristics and permeation performance conditions can be satisfied by changing the processing temperature and the type of thermoplastic resin to be selected. Can be adjusted.

Further, as shown in FIGS. 2 and 3, the shape of the projection 301 in the planar direction of the separation membrane may be linear as a whole, and other shapes are, for example, curved, sawtooth, and wavy. There may be. Moreover, in these shapes, the protrusion 301 may have a broken line shape or a dot shape. From the viewpoint of reducing the flow resistance, a dot shape or a broken line shape is preferable. However, since the flow path material is interrupted, the number of places where film sagging occurs during pressure filtration increases.

Further, when the shape of the projection 301 in the planar direction of the sheet 302 is a straight line, the adjacent flow path members may be arranged substantially parallel to each other. “Arranged substantially in parallel” means, for example, that the channel material does not intersect on the separation membrane, the angle formed by the longitudinal direction of two adjacent channel materials is 0 ° or more and 30 ° or less, It includes that the angle is from 0 ° to 15 °, and that the angle is from 0 ° to 5 °.

The angle formed between the longitudinal direction of the protrusion 301 and the longitudinal direction of the water collecting pipe 6 is preferably 60 ° or more and 120 ° or less, more preferably 75 ° or more and 105 ° or less, and 85 ° or more and 95. More preferably, it is not more than 0 °. When the angle formed by the longitudinal direction of the flow path material and the longitudinal direction of the water collecting pipe is within the above range, the permeated water is efficiently collected in the water collecting pipe.

In order to form the flow path stably, it is preferable that the separation membrane can be prevented from dropping when the separation membrane is pressurized in the separation membrane element. For this purpose, it is preferable that the contact area between the separation membrane and the channel material is large, that is, the area of the channel material relative to the area of the separation membrane (projected area of the channel material with respect to the membrane surface of the separation membrane) is large. On the other hand, in order to reduce pressure loss, it is preferable that the cross-sectional area of a flow path is wide. In order to ensure a large cross-sectional area of the flow path while ensuring a large contact area between the separation membrane and the flow path material perpendicular to the longitudinal direction of the flow path, The shape is preferably a concave lens. Further, the protrusion 301 may have a straight column shape having no change in width in a cross-sectional shape in a direction perpendicular to the winding direction. In addition, the protrusion 301 is a trapezoidal wall-like object or elliptical column whose width changes in the cross-sectional shape in the direction perpendicular to the winding direction as long as it does not affect the separation membrane performance. The shape may be an elliptical cone, a quadrangular pyramid, or a hemisphere.

The shape of the protrusion 301 is not limited to the shape shown in FIGS. When the flow path material is arranged by fixing a molten material to the sheet 302, for example, as in the hot melt method, the required separation is achieved by changing the processing temperature and the type of hot melt resin to be selected. The shape of the protrusion 301 can be freely adjusted so that the conditions of the characteristics and the transmission performance can be satisfied.

In FIG. 2, the planar shape of the protrusion 301 is linear in the length direction. However, the protrusion 301 can be changed to another shape as long as it is convex to the surface of the separation membrane 2 and does not impair the desired effect as the separation membrane element. That is, the shape of the channel material (projection) in the planar direction may be a curved shape, a wavy shape, or the like. A plurality of flow path materials (projections) included in one separation membrane may be formed so that at least one of the width and the length is different from each other.

(Projected area ratio)
The projected area ratio of the protrusions 301 to the permeation side surface of the separation membrane is 0.03 or more and 0.85 or less, particularly in terms of reducing the flow resistance of the permeation side flow path and forming the flow path stably. Is preferably 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. The projected area ratio is the projected area of the channel material obtained when the separation membrane and the permeation side channel material are cut out at 5 cm × 5 cm and the permeation side channel material is projected onto a plane parallel to the surface direction of the separation membrane. Is divided by the cut-out area (25 cm ² ).

(Defect rate)
As shown in FIG. 5, 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 passed through a region far from the water collecting pipe, that is, a region in the vicinity of the outer end in the winding direction (region near the right end in FIG. 5) Then, it merges with the water that has permeated through the inner area, and goes to the water collecting pipe 6. Therefore, in the permeate side flow path, the amount of water present is smaller in the direction far from the water collecting pipe 6.

Therefore, there is no permeation-side flow path material in the region near the end on the outer side in the winding direction, and even if the flow resistance in that region becomes high, the influence on the water production amount of the entire separation membrane element is slight. . For the same reason, the formation accuracy of the flow path material is low in the region near the end on the outer side in the winding direction, and the resin forming the flow path material is continuously applied in the first direction (the width direction of the separation membrane). However, the influence on the amount of fresh water as a separation membrane element is small. In this region, the same applies to the case where the resin forming the flow path material is applied without any gap in the surface direction (xy plane) of the separation membrane.

Therefore, as shown in FIG. 6, the distance from the outer end in the winding direction of the permeate channel material to the outer end in the winding direction of the projection 301, that is, the outer end in the winding direction of the separation membrane 2. The length L3 in the second direction (length direction of the separation membrane) of the region R3, which is a region provided in the region where the permeation side flow channel is not formed, is the second permeation side flow channel material. The ratio of the length to the length L1 (corresponding to “a” described above) is preferably 0% or more and 30% or less, more preferably 0% or more and 10% or less, and particularly preferably 0% or more and 3% or less. preferable. This ratio is called a defect ratio. Region R2 is a region where a permeate-side flow path is formed.

The defect rate is represented by (L3 / L1) × 100 (%) in FIG.
For convenience of explanation, FIG. 6 shows a form in which the protrusion 301 is not provided in the region R3. However, the region R3 may be a region provided with continuous protrusions in the width direction.

FIG. 6 is a cross-sectional view of the end portion on the outer side in the winding direction of the permeate-side channel material cut in the length direction of the protrusion 301. In FIG. 6, the protrusion 301 is fixed to the sheet 302 and extends to the front of the outer end in the winding direction of the permeate-side channel material. For convenience of explanation, FIG. 6 shows a form in which the protrusions 301 are continuously provided in the length direction. However, as described above, the various forms described above are applied as the protrusions 301. It is.

In FIG. 6, a region where the permeate side channel material is provided is indicated by R2, and a region where the projection 301 (permeate side channel material) is not provided is indicated by R3. The length of the separation membrane 2 in the MD direction is L1, the length of the protrusion 301 in the MD direction (that is, the length of the region R2) is L2, and the length of the region R3 in which the protrusion 301 is not present is L3. Show. Here, the MD direction represents the length direction of the separation membrane and the winding direction of the separation membrane.

[2. Separation membrane element)
(2-1) Overview As shown in FIG. 5, the separation membrane element 100 includes the water collection pipe 6 and the separation membrane 2 wound around the water collection pipe 6 with any of the above-described configurations.

(2-2) Separation membrane <Overview>
As shown in FIG. 5, the separation membrane 2 is wound around the water collecting pipe 6, and is arranged so that the width direction of the separation membrane 2 is along the longitudinal direction of the water collecting pipe 6. As a result, the separation membrane 2 is disposed such that the length direction is along the winding direction.

Therefore, as shown in FIG. 5, the protrusions 301 are disposed discontinuously on at least the longitudinal direction of the water collecting pipe 6 on the permeation side surface 22 of the separation membrane 2. That is, the permeate-side channel 5 is formed so as to be continuous from the outer end to the inner end of the separation membrane in the winding direction. As a result, the permeated water can easily reach the central water collecting pipe 6, that is, the flow resistance is reduced, so that a large amount of fresh water can be obtained.

“Inside in winding direction” and “outside in winding direction” are as shown in FIG. That is, the “inner end in the winding direction” and the “outer end in the winding direction” correspond to the end closer to the water collecting pipe 6 and the far end in the separation membrane 2, respectively.

As described above, since the flow path material does not have to reach the edge of the separation membrane, for example, in FIG. 5, the outer end of the envelope-shaped membrane (separation membrane 2) in the winding direction and the longitudinal direction of the water collection tube In the end portion of the envelope membrane (separation membrane 2), a flow path material may not be provided.

<Membrane leaf and envelope membrane>
As shown in FIG. 1, the separation membrane forms a membrane leaf 4 (sometimes simply referred to as “leaf” in this document). In the leaf 4, the separation membrane 2 a is arranged so that the supply-side surface 21 a faces the supply-side surface 21 b of another separation membrane 2 b with a supply-side channel material (not shown) interposed therebetween. In the membrane leaf 4, a supply-side flow path is formed between the supply-side surfaces of the separation membranes facing each other.

Further, as shown in FIG. 1, the two membrane leaves 4 are overlapped so that the permeation side surface 22b of the separation membrane 2b faces the permeation side surface 22c of the separation membrane 2c of the other membrane leaf. The membrane leaf 4 forms an envelope-like film. The envelope membrane is a pair of separation membranes (one consisting of

separation membranes

2b and 2c) arranged so that the surfaces on the permeate side facing each other face each other. The envelope-shaped membrane is rectangular, and the permeate side surface is rectangular in the separation membrane so that the permeate flows into the water collecting pipe 6, and is opened only on one side in the winding direction, and on the other three sides. Is sealed. The permeate is isolated from the raw water by this envelope membrane.

Sealing includes 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 particularly preferable because it is the simplest and most effective.

Also, on the surface on the supply side of the separation membrane, the inner end in the winding direction is closed by folding or sealing. Since the supply side surface of the separation membrane is sealed rather than folded, bending at the end of the separation membrane hardly occurs. 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.

Thus, by suppressing the occurrence of leaks, the recovery rate of the envelope film is improved. The recovery rate of the envelope 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.

The 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 membrane leaf is formed by folding, the longer the 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 leaf is long.

In the membrane leaf and the envelope membrane, the separation membranes facing each other (

separation membranes

2b and 2c in FIG. 1) may have the same configuration or different configurations. That is, in the separation membrane element, at least one of the two permeation-side surfaces facing each other only needs to be provided with the above-described permeation-side flow passage material, so that the separation membrane provided with the permeation-side flow passage material and the permeation side Separation membranes that do not include a channel material may be alternately stacked. 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 that has the same configuration as the separation membrane).

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

(2-3) Permeate-side flow path As described above, the separation membrane 2 includes the protrusions 301. By the protrusion 301, a permeate-side flow path is formed inside the envelope-shaped membrane, that is, between the permeate-side surfaces of the facing separation membrane.

(2-4) Supply side channel (Channel material)
In the separation membrane element 100, the supply-side flow path material in which the projected area ratio with respect to the separation membrane 2 exceeds 0 and is less than 1 between the surfaces on the supply side of the facing separation membrane (see reference numeral 32 in FIGS. 8 and 9). Is provided. 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. . When the projected area ratio is 0.03 or more and 0.50 or less, the flow resistance can be suppressed to be relatively small. The projected area ratio is the projected area of the channel material 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. Is divided by the cut-out area (25 cm ² ).

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 in consideration of the balance of each performance and operation cost as described later.

The shape of the supply-side channel material is not particularly limited, and may have a continuous shape or a discontinuous shape. Examples of the 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 flow path material. The continuous shape may include a portion where a part of the flow path material is discontinuous to such an extent that a problem such as a decrease in the amount of water produced does not occur. The definition of “discontinuity” is as described for the passage-side channel material (see paragraph 0077). The material of the supply side channel material is not particularly limited, and may be the same material as the separation membrane or a different material.

(Concavity and convexity processing)
Further, instead of disposing the supply-side channel material on the supply-side surface of the separation membrane, a difference in height can be imparted to the supply side of the separation membrane by methods such as embossing, hydraulic forming, and calendering.

Examples of the embossing method include roll embossing, and the pressure and processing temperature for carrying out this can be determined as appropriate according to the melting point of the separation membrane. For example, when the separation membrane has a porous support layer containing an epoxy resin, the linear pressure is preferably 10 kg / cm or more and 60 kg / cm or less, and the heating temperature is preferably 40 ° C. or more and 150 ° C. or less. Moreover, when it has a porous support layer containing heat resistant resins, such as polysulfone, it is preferable that it is 10 kg / cm or more and 70 kg / cm or less of linear pressure, and 70 to 160 degreeC of roll heating temperature is preferable. In any case of roll embossing, a winding speed of 1 m / min to 20 m / min is preferable.

When embossing is performed, the shape of the roll handle is not particularly limited, but it is important to reduce the flow resistance of the flow path and stabilize the flow path when supplying and permeating fluid to the separation membrane element. is there. In these respects, there are ellipses, circles, ellipses, trapezoids, triangles, rectangles, squares, parallelograms, rhombuses, and irregular shapes in the shape observed from the upper surface. Those formed in the surface direction, those formed in a widened form, and those formed in a narrowed form are used.

The difference in height of the supply side surface of the separation membrane that can be imparted by embossing can be freely adjusted by changing the pressure heat treatment conditions so as to satisfy the conditions that require separation characteristics and water permeation performance. However, if the height difference of the supply side surface of the separation membrane is too deep, the flow resistance becomes small, but when a separation membrane element is produced, the number of membrane leaves that can be filled in one separation membrane element is reduced. If the difference in height on the supply side surface of the separation membrane is small, the flow resistance of the flow path increases, and the separation characteristics and water permeation performance deteriorate. Therefore, the water production capacity of the separation membrane element is reduced, and the operation cost for increasing the amount of water produced is increased.

Therefore, in consideration of the balance of each performance and the operating cost described above, in the separation membrane, the difference in height on the supply side surface of the separation membrane is preferably more than 0.5 mm and preferably 2.0 mm or less, and 0.6 mm or more. 1.0 mm or less is more preferable.

The height difference on the supply side surface of the separation membrane can be obtained by the same method as in the case of the height difference on the separation membrane permeation side described above.

The groove width (interval of the supply side channel material) is preferably 0.2 mm or more and 10 mm or less, more preferably 0.5 mm or more and 3 mm or less.

The pitch should be appropriately designed between 1/10 and 50 times the groove width. The groove width is the distance between the sinking parts on the surface where the height difference exists, and the pitch is the horizontal from the highest point of the high part to the highest part of the adjacent high part on the surface where the height difference exists. It is distance.

The projected area ratio of the part that becomes convex by embossing (the ratio of the projected area that is obtained when the convex part is projected onto the surface parallel to the surface direction of the separation membrane) is the same reason as in the case of the supply-side channel material Therefore, it is preferably 0.03 or more and 0.5 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.

The “height difference” in the surface of the separation membrane is a difference in height between the surface of the separation membrane and the apex of the flow channel material (that is, the height of the flow channel material). And the height difference between the convex portions.

(2-5) Water Collection Pipe The water collection pipe 6 (see FIGS. 8 to 10) may be configured so that permeate flows through it, and the material, shape, size, etc. are not particularly limited. As the water collecting pipe 6, for example, a cylindrical member having a side surface provided with a plurality of holes is used.

(2-6) First Mode As more specific modes, FIGS. 8 to 10 show

separation membrane elements

100A, 100B, and 100C according to first to third modes. FIG. 8 is an explanatory view showing the separation membrane element 100 </ b> A of the first embodiment partially disassembled, and a plurality of separation membranes 2 are wound around the water collection pipe 6. In addition to the above-described configuration, the separation membrane element 100A further includes the following configuration.

That is, the separation membrane element 100A includes end plates 92 with holes at both ends (that is, the first end and the second end). In the separation membrane element 100A, an outer package 81 is wound around the outer peripheral surface of the wound separation membrane (hereinafter referred to as “wrapping body”).
The holeless end plate 91 described later does not include a hole through which raw water can pass, whereas the holed end plate 92 includes a plurality of holes through which the raw water can pass.

Further, the separation membrane 2 forms an envelope membrane 11, and the protrusion 301 is arranged inside the envelope membrane 11 as described above. A supply-side channel material 32 is disposed between the envelope-shaped films 11.

For convenience, in FIG. 8, FIG. 9, and FIG. 10, the protrusion 301 (permeation-side channel material) is shown as a dot shape, but as described above, the shape of the permeation-side channel material is not limited to this shape. .

Next, water treatment using the separation membrane element 100A will be described. The raw water 101 supplied from the first end of the separation membrane element 100A flows into the supply-side flow path through the hole of the end plate 92. In this way, the raw water 101 in contact with the supply side surface of the separation membrane 2 is separated into the permeated water 102 and the concentrated water 103 by the separation membrane 2. The permeated water 102 flows into the water collecting pipe 6 through the permeate side flow path. The permeated water 102 that has passed through the water collection pipe 6 flows out of the separation membrane element 100A from the second end of the separation membrane element 100A. The concentrated water 103 flows out of the separation membrane element 100A from the hole of the end plate 92 provided at the second end through the supply side flow path.

(2-7) Second Embodiment With reference to FIG. 9, the separation membrane element 100B of the present embodiment will be described. In addition, about the component already demonstrated, the same code | symbol is attached | subjected and the description is abbreviate | omitted.

The separation membrane element 100B includes an end plate 91 that is arranged at the first end and has no holes, and an end plate 92 that is arranged at the second end and has holes. Further, the separation membrane element 100B includes a porous member 82 that is further wound around the outermost surface of the surrounded separation membrane 2.

As the porous member 82, a member having a plurality of holes through which raw water can pass is used. These holes provided in the porous member 82 may be referred to as raw water supply ports. As long as the porous member 82 has a plurality of holes, the material, size, thickness, rigidity and the like are not particularly limited. By adopting a member having a relatively small thickness as the porous member 82, the membrane area per unit volume of the separation membrane element can be increased.

The thickness of the porous member 82 is, for example, 1 mm or less, 0.5 mm or less, or 0.2 mm or less. Further, the porous member 82 may be a member having flexibility or flexibility that can be deformed so as to follow the outer peripheral shape of the wound body. More specifically, as the porous member 82, a net, a porous film, or the like can be applied. The net and the porous film may be formed in a cylindrical shape so that the wound body can be accommodated therein, or may be long and wound around the wound body.

The porous member 82 is disposed on the outer peripheral surface of the separation membrane element 100B. By providing the porous member 82 in this manner, holes are provided on the outer peripheral surface of the separation membrane element 100B. It can be said that the “outer peripheral surface” is a portion excluding the first end surface and the second end surface in the entire outer peripheral surface of the separation membrane element 100B. In this embodiment, the porous member 82 is disposed so as to cover almost the entire outer peripheral surface of the wound body.

According to the present embodiment, raw water is supplied from the outer peripheral surface of the separation membrane element 100B (the outer peripheral surface of the wound body) via the porous member 82. Therefore, even if the separation membrane element 100B is repeatedly operated or the separation membrane element 100B is operated under a high pressure condition, deformation of the wound body due to the surrounding separation membrane 2 and the like being pushed out in the longitudinal direction ( It is possible to suppress so-called telescopes. Furthermore, in this embodiment, since raw | natural water is supplied from the clearance gap between a pressure vessel (not shown) and a separation membrane element, generation | occurrence | production of the abnormal stagnation of raw | natural water is suppressed.

In the separation membrane element 100B, since the end plate at the first end is the end plate 91 without holes, the raw water does not flow into the separation membrane element 100B from the surface of the first end. The raw water 101 is supplied to the separation membrane 2 through the porous member 82 from the outer peripheral surface of the separation membrane element 100B. The raw water 101 supplied in this way is divided into permeated water 102 and concentrated water 103 by the separation membrane. The permeated water 102 passes through the water collection pipe 6 and is taken out from the second end of the separation membrane element 100B. The concentrated water 103 flows out of the separation membrane element 100B through the hole of the end plate 92 with a hole at the second end.

(2-8) Third Embodiment With reference to FIG. 10, the separation membrane element 100C of the present embodiment will be described. In addition, about the component already demonstrated, the same code | symbol is attached | subjected and the description is abbreviate | omitted.

The separation membrane element 100C is the same as the element of the second embodiment except that the separation membrane element 100C is provided at each of the first end and the second end and includes an end plate 92 having holes. In addition, the separation membrane element 100C includes a porous member 82, like the separation membrane element 100B.

With this configuration, in this embodiment, the raw water 101 is not only supplied from the outer peripheral surface of the separation membrane element 100C to the envelope through the hole of the porous member 82, but also the end plate 92 with a hole at the first end. The separation membrane element 100 </ b> C is supplied to the winding body through the first hole. The permeated water 102 and the concentrated water 103 are discharged from the second end to the outside of the separation membrane element 100C, similarly to the separation membrane element 100A of the first form.

Since the raw water is supplied not only from one end of the separation membrane element 100C (that is, the end plate 92 having a hole) but also from the outer peripheral surface of the separation membrane element 100C through the porous member 82, Deformation can be suppressed. Also in this embodiment, since the raw water is supplied from the gap between the pressure vessel and the separation membrane element, the occurrence of abnormal stagnation is suppressed.

[3. Method for manufacturing separation membrane element]
Each process in the manufacturing method of a separation membrane element is demonstrated below.
(3-1) Production of Separation Membrane and Post-Processing The production method of the separation membrane has been described above.
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. Furthermore, chemical treatment with chlorine, acid, alkali, nitrous acid or the like is performed to improve separation performance and permeation performance as necessary, and the monomer is washed to produce a continuous sheet of separation membrane.

Before or after the chemical treatment, the separation membrane may be uneven by embossing or the like, or a flow path material may be formed on the permeation side surface and / or the supply side surface of the separation membrane with a resin. Also good.
When unevenness processing is performed on the separation membrane, a difference in height can be imparted to the supply side of the separation membrane by methods such as embossing, hydraulic forming, and calendering.

When embossing is performed, the shape of the roll handle is not particularly limited, but it is important to reduce the pressure loss of the flow path and stabilize the flow path when supplying and permeating fluid to the separation membrane element. is there. In these respects, an ellipse, a circle, an ellipse, a trapezoid, a triangle, a rectangle, a square, a parallelogram, a rhombus, an indefinite shape, and the like are adopted as the shape observed from the upper surface. In addition, three-dimensionally, it may be formed so that the width becomes smaller as the height is higher, or conversely, it may be formed so that the width becomes wider as the height is higher, regardless of the height. They may be formed with the same width.
The difference in height on the supply-side surface of the separation membrane that can be imparted by embossing can be freely adjusted by changing the pressure heat treatment conditions so as to satisfy the conditions that require separation characteristics and water permeation performance.

As described above, when the supply-side flow path is formed by fixing the supply-side flow path material to the separation membrane main body, or when the supply-side flow path material is formed by roughening the membrane, these supplies are supplied. The step of forming the side channel may be regarded as one step in the separation membrane manufacturing method.

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 What is necessary is just to overlap with a road material.

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

Examples of the method for arranging the flow path 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.

(3-2) Formation of membrane leaf As described above, the membrane leaf may be formed by folding the separation membrane so that the surface on the supply side faces inward, or two separate separation membranes may be formed. It may be formed by bonding so that the surfaces on the supply side face each other.

It is preferable that the manufacturing method of the separation membrane element includes a step of sealing the inner end portion in the winding 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 so that the permeated water can flow into the water collecting pipe 6.

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 particularly preferable because it is the simplest and most effective.

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

Either the supply-side sealing or the permeation-side sealing (envelope-like membrane formation) may be performed first, or the supply-side sealing is performed while stacking separation membranes. And the sealing of the surface on the transmission side may be performed in parallel. However, in order to suppress the generation of wrinkles in the separation membrane during winding, the adhesive or hot melt at the end in the width direction is allowed to allow the adjacent separation membranes 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 an envelope-like film, after the winding is completed.

(3-3) Formation of an envelope-like membrane A sheet of separation membrane is folded so that the permeation side faces inward, and a sheet having the above-mentioned protrusions is sandwiched between the opposing separation membranes, and bonded together. Or by laminating two separation membranes so that the permeation side faces inward and sandwiching a sheet comprising the above-mentioned protrusions between one separation membrane and another separation membrane, An envelope-like 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 bonding with an adhesive or hot melt, or by fusion with heat or laser.
At this time, in the sealed part, a sheet may exist between the separation membranes, or the sheet may be arranged inside the sealing part of the separation membrane.

The adhesive used for forming the envelope film preferably has a viscosity in the range of 40 P (poise) to 150 P (poise), more preferably 50 P (poise) to 120 P (poise). If the adhesive viscosity is too high, wrinkles are likely to occur when the laminated leaves are wrapped around the water collection pipe. Wrinkles may impair the performance of the separation membrane element. Conversely, if the adhesive viscosity is too low, the adhesive may flow out of the end of the leaf and soil the device. Moreover, when an adhesive adheres to a portion other than the portion to be bonded, the performance of the separation membrane element is impaired, and the work efficiency is significantly reduced due to the processing operation of the adhesive that has flowed out.

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

As the adhesive, a urethane-based adhesive is preferable, and in order to make the viscosity in a range of 40 P (poise) or more and 150 P (poise) or less, the main component isocyanate and the curing agent polyol are mixed with an isocyanate / polyol weight ratio of 1 / What mixed so that it might become 5 or more and 1 or less is preferable. The viscosity of the adhesive is obtained by measuring the viscosity of a mixture in which the main agent, the curing agent alone, and the blending ratio are defined in advance with a B-type viscometer (JIS K 6833).

When a sheet exists in the sealing part, the separation membranes can be bonded to each other through the sheet by an adhesive soaked in the sheet. Moreover, when there is no sheet | seat in a sealing part, a separation membrane is bonded together directly.

(3-4) Separation membrane winding A conventional element manufacturing apparatus can be used to manufacture the separation membrane element. In addition, as an element manufacturing method, methods described in reference documents (Japanese Patent Publication No. 44-14216, Japanese Patent Publication No. 4-11928, Japanese Patent Application Laid-Open No. 11-226366) can be used. Details are as follows.

When the separation membrane is wound around the water collecting pipe, the separation membrane is arranged so that the closed end of the leaf, that is, the closed portion of the envelope-shaped membrane faces the water collecting pipe. By winding 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 wound around the water collection pipe, the adhesive applied to the water collection pipe will not flow easily when the separation membrane element is wrapped, leading to suppression of leakage, and the flow path around the water collection pipe Is secured stably. The spacer may be wound longer than the circumference of the water collecting pipe.

(3-5) Other steps The method of manufacturing a separation membrane element may include further winding a film, a filament, and the like around the wound body of the separation membrane formed as described above. Further steps such as edge cutting for aligning the end of the separation membrane in the longitudinal direction of the water collecting pipe, attachment of an end plate, and the like may be included.

[4. (Use of separation membrane element)
The separation membrane element may be further used as a separation membrane module by being connected in series or in parallel and housed in a pressure vessel.

Also, the separation membrane element and the separation membrane module described above can be combined with a pump that supplies fluid to them, a device that pretreats the fluid, and the like to form a fluid separation device. By using this separation device, for example, raw water can be separated into permeated water such as drinking water and concentrated water that has not permeated through the membrane, and water suitable for the purpose can be obtained.

The higher the operating pressure of the fluid separator, the higher the removal rate, but the energy required for operation also increases, and considering the retention of the separation membrane element supply channel and permeation channel, the membrane module The operating pressure when passing through the water to be treated is preferably 0.2 MPa or more and 5 MPa or less. As the raw water temperature increases, the salt removal rate decreases, but as the raw water temperature decreases, the membrane permeation flux also decreases. Moreover, when the pH of the raw water is in a neutral region, even if the raw water is a high salt concentration liquid such as seawater, the generation of scales such as magnesium is suppressed, and the deterioration of the membrane is also suppressed.

The fluid to be treated by the separation membrane element is not particularly limited, but when used for water treatment, as raw water, seawater, brine, drainage, etc., 500 mg / L or more and 100 g / L or less TDS (Total Dissolved Solids: total dissolved solids) For example). In general, TDS indicates the total dissolved solid content, and is expressed by “mass / volume”, but 1 L may be expressed as 1 kg and may be expressed by “weight ratio”. According to the definition, the solution filtered through a 0.45 μm filter can be calculated from the weight of the residue by evaporating at a temperature of 39.5 ° C. or higher and 40.5 ° C. or lower. Convert.

Hereinafter, the present invention will be described in more detail with reference to examples, but the present invention is not limited to these examples.

(Sheet thickness and protrusion height)
The thickness of the sheet and the height of the protrusions were measured with a high-precision shape measuring system KS-1100 manufactured by Keyence Corporation. Specifically, the height of the projections was analyzed for average height difference from the measurement result on the transmission side of 5 cm × 5 cm using a high precision shape measurement system KS-1100 manufactured by Keyence Corporation. Thirty points having a height difference of 10 μm or more were measured, and the value obtained by dividing the sum of the height values by the number of total measurement points (30 points) was taken as the height of the protrusion.

(Pitch and spacing, width, length of permeate side channel material)
Using a high-precision shape measurement system KS-1100 manufactured by Keyence Corporation, the horizontal distance from the apex of the channel material on the permeate side of the separation membrane to the apex of the adjacent channel material was measured at 200 locations, and the average value was pitched Calculated as
Further, the distances b, e, width d, and length f were measured by the above-described method in the photograph in which the pitch was measured (see FIGS. 2 and 3).

(Porosity)
The apparent volume (cm ³ ) of the dried sample was measured, and the weight was then measured by adding pure water to the sample. The value obtained by subtracting the dry weight of the sample from the weight of the sample containing water, that is, the weight of the water (g: volume of water cm ³ ) entering the voids of the substrate was calculated and divided by the apparent volume of the sample. The porosity was obtained as a percentage (%).

(Thickness unevenness of the sheet)
About the permeation | transmission side channel material with which the protrusion adhered to the sheet | seat, the sample cut was carried out to CD direction. Using a digital microscope VHX1100 manufactured by Keyence Co., Ltd., the sheet thickness was measured at a magnification of 50 times at a position equivalent to 30 sheets with respect to the sheet width, and the difference between the maximum value and the minimum value was defined as thickness unevenness.

(Width of band-shaped end of permeate side channel material)
Measure the distance from the end of the sheet to the protrusions at two magnifications in the width direction (CD direction) of the permeate-side channel material using a Keyence digital microscope VHX1100 at a magnification of 50 times. The average value from the shortest distance to the tenth shortest distance was calculated, and the average value was defined as the width of the belt-shaped end.
Width of band-shaped end = (average value of width of one band-shaped end + average value of width of other band-shaped end) / 2

(durability)
Most of the water remaining in the separation membrane element was removed, and vacuum suction was performed from one end of the water collecting tube 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, “good”, “good”, and “good” were accepted.
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: The degree of element vacuum after 15 seconds was 55 kPa or less. The above evaluation was performed on 15 elements, and the most obtained result was regarded as durability.

(Unwindability of wound body)
The permeation side channel material (width 1 m), that is, the sheet on which the protrusions were arranged, was wound up 100 m at an unwinding tension of 30 N and a winding tension of 30 N, and stored at room temperature for 1 week. Then, the permeation | transmission side flow path material was unwound, confirmation of the adhesion to the sheet | seat which a protrusion faces, and the height change of a protrusion were measured.

(Water production)
The separation membrane or separation membrane element was sampled for 10 minutes after operating for 100 hours under conditions of an operating pressure of 0.7 MPa and a temperature of 25 ° C. using an aqueous NaCl solution having a concentration of 1,000 mg / L and pH 6.5 as the feed water. The water permeation amount (cubic meter) per unit area of the membrane and per day was expressed as the amount of water produced (m ³ / day).

(Desalination rate (TDS removal rate))
For the raw water and the sampled permeate used in the operation for 10 minutes in measuring the amount of water produced, the TDS concentration was determined by conductivity measurement, and the TDS removal rate was calculated from the following formula.
TDS removal rate (%) = 100 × {1− (TDS concentration in permeated water / TDS concentration in raw water)}

(Defect rate)
The defect rate is a numerical value obtained by dividing “the length of the region where the permeation-side flow path is not formed in the length direction of the separation membrane” by “the length of the separation membrane”.

Example 1
A 15.0 wt% DMF solution of polysulfone on a non-woven fabric made of polyethylene terephthalate fibers (yarn diameter: 1 dtex, thickness: about 0.09 mm, density 0.80 g / cm ³ ) at a thickness of 180 μm at room temperature (25 ° C.) The porous support layer (thickness: 0.13 mm) consisting of a fiber-reinforced polysulfone support membrane is prepared by immediately immersing it in pure water and leaving it for 5 minutes and then immersing it in warm water at 80 ° C. for 1 minute. did.

Thereafter, the porous support layer roll was unwound, and the polysulfone surface was coated with 1.8% by weight of m-PDA (metaphenylenediamine) and 4.5% by weight of ε-caprolactam, and nitrogen was blown from the air nozzle. After removing the excess aqueous solution from the surface of the support membrane, an n-decane solution at 25 ° C. containing 0.06% by weight of trimesic acid chloride was applied so that the surface was completely wetted.

After that, the excess solution is removed from the membrane by air blow, washed with hot water at 50 ° C., immersed in a 5% glycerin aqueous solution for 1 minute, treated in a hot air oven at 100 ° C. for 30 seconds, and semi-dried. A separation membrane roll was obtained.

The separation membrane thus obtained was folded and cut so that the effective area at the separation membrane element was 37.0 m ^2, and the net (thickness: 0.7 mm, pitch: 5 mm × 5 mm, fiber diameter: 350 μm, Twenty-six leaves having a width of 900 mm and a leaf length of 800 mm were produced using a projected area ratio of 0.13) as a supply-side channel material.

On the other hand, protrusions were formed over the entire sheet (nonwoven fabric, thread diameter: 1 dtex, thickness: 0.02 mm, porosity 60%, thickness unevenness 0.003 mm). That is, using a gravure roll while adjusting the temperature of the backup roll to 15 ° C., polypropylene (trade name: S10CL, manufactured by Prime Polymer Co., Ltd.) was applied to the sheet to produce a permeate-side channel material. The resin temperature was 220 ° C., and the processing speed was 6.0 m / min. The pattern engraved on the surface of the gravure roll was a hemispherical dot with a diameter of 0.5 mm arranged in a staggered pattern, and the dot pitch was 1.0 mm. The distance between the strip-shaped end portions was 25 mm.

The shape of the obtained protrusions is such that the total of the thickness of the sheet and the height of the protrusions is 0.26 mm, the channel material width is 0.5 mm, and the adjacent channels in the first direction and the second direction. The spacing between the materials was 0.4 mm and the pitch was 0.9 mm. Here, the pitch is an average value of the horizontal distances from the vertexes of the convex portions of the separation membrane to the vertexes of the neighboring convex portions, measured at 200 locations on the transmission side surface.

A permeate-side channel material is laminated on the permeate side surface of the obtained leaf, and is collected in an ABS (acrylonitrile-butadiene-styrene) water collecting pipe (width: 1,020 mm, diameter: 30 mm, 40 holes × straight line). The film was wound in a spiral shape, and a film was further wound around the outer periphery. After fixing with tape, edge cutting, end plate attachment, and filament winding were performed to produce a separation membrane element having a diameter of 8 inches. Both end plates were perforated end plates. That is, in this example, the separation membrane element of the first form shown in FIG. 8 was produced.

When the separation membrane element was placed in a pressure vessel and operated using an aqueous NaCl solution having a concentration of 1,000 mg / L and pH 6.5, and operating at an operating pressure of 0.7 MPa, an operating temperature of 25 ° C., and a pH of 6.5 (recovery rate of 15%), The amount of water produced, the desalting rate, and the durability were as shown in Table 1, and the unwinding property was also good.

(Example 2)
Hereinafter, separation membranes were produced in the same manner as in Example 1 under conditions not specifically mentioned.
A separation membrane and a separation membrane element were prepared in the same manner as in Example 1 except that the protrusions were placed on the sheet while feeding nitrogen gas into the resin, and the porosity of the protrusions was set to 4%.
When the separation membrane element was put in a pressure vessel and operated under the above-mentioned conditions to obtain permeated water, the water production amount, the desalting rate, and the durability were as shown in Table 1, and the unwinding property was also good. .

(Examples 3 to 11)
A separation membrane and a separation membrane element were produced in the same manner as in Example 1 except that the sheet was a non-woven fabric as shown in Tables 1 to 3 and the protrusions were as shown in Tables 1 to 3.
When the separation membrane element was placed in a pressure vessel and operated under the above conditions to obtain permeated water, the amount of water produced, the desalting rate, and the durability were as shown in Tables 1 to 3, and the unwinding property was also good. there were.

Example 12
The sheet is a non-woven fabric (thread diameter: 1 dtex, thickness: about 0.1 mm, porosity 55%), the height of the projection is 0.16 mm, and the projection is continuously arranged in the length direction of the sheet Were prepared in the same manner as in Example 1 to prepare a separation membrane and a separation membrane element.
When the separation membrane element was put in a pressure vessel and operated under the above-mentioned conditions to obtain permeated water, the amount of water produced, the desalting rate, and the durability were as shown in Table 3, and the unwinding property was also good. .

(Examples 13 to 16)
A separation membrane and a separation membrane element were produced in the same manner as in Example 1 except that the sheet was a non-woven fabric as shown in Table 4 and the protrusions were as shown in Table 4. When the separation membrane element was put in a pressure vessel and operated under the above-mentioned conditions to obtain permeated water, the water production amount, the desalting rate, and the durability were as shown in Table 4, and the unwinding property was also good. .

(Examples 17 and 18)
A separation membrane and a separation membrane element were produced in the same manner as in Example 1 except that the sheet was a non-woven fabric as shown in Table 5 and the protrusions were as shown in Table 5. The effective film area was different from that in Example 1 by the difference in the width of the band-like region.
When the separation membrane element was put in a pressure vessel and operated under the above-mentioned conditions to obtain permeated water, the water production amount, the desalting rate, and the durability were as shown in Table 5, and the unwinding property was also good. .

(Examples 19 and 20)
Folded and cut so that the effective area of the separation membrane is 0.5 m ² and supplied the net (thickness: 510 μm, pitch: 2 mm × 2 mm, fiber diameter: 255 μm, projected area ratio: 0.21) And two leaves with a width of 230 mm were produced using the permeation-side channel material of Table 5.
After that, a separation membrane element in which two leaves were spirally wound while being wound around an ABS water collecting pipe (width: 300 mm, outer diameter: 17 mm, number of holes: 8 × two straight lines) was prepared, and a film was placed on the outer periphery. After winding and fixing with tape, edge cutting and end plate mounting were performed to produce a 2-inch element.
When the separation membrane element was put in a pressure vessel and operated under the above-mentioned conditions to obtain permeated water, the water production amount, the desalting rate, and the durability were as shown in Table 5, and the unwinding property was also good. .

(Comparative Example 1)
A separation membrane and a separation membrane element were produced in the same manner as in Example 1 except that the sheet was a non-woven fabric as shown in Table 6 and the protrusions were as shown in Table 6.
When the separation membrane element was put in a pressure vessel and operated under the above conditions to obtain permeated water, the amount of fresh water was reduced due to the reduction of the effective membrane area, and the amount of fresh water, desalination rate and durability were as shown in Table 6. The unwindability was good.

(Comparative Example 2)
A separation membrane was prepared in the same manner as in Example 1. Subsequently, separation membrane elements were produced in the same manner as in Comparative Example 1 except that the protrusions were placed on the sheet while feeding nitrogen gas into the resin, and the porosity of the protrusions was set to 60%.
When the separation membrane element was placed in a pressure vessel and operated under the above-mentioned conditions to obtain permeate, the projections were compressed and the flow path was reduced, resulting in a significant decrease in the amount of water produced. The salt ratio was as shown in Table 6. Moreover, when the wound body was unwound, the height of the protrusion was reduced by 5%. There was no air leak.

(Comparative Example 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 Comparative Example 1 except that a biaxially stretched polyester film (Toray Lumirror, thickness 0.03 mm) was used as the sheet.
When the separation membrane element was put in a pressure vessel and operated under the above-mentioned conditions to obtain permeated water, adhesion between the leaves was not sufficient and air leakage occurred. Further, the amount of water produced was so large that measurement was impossible, and the desalting rate was as shown in Table 6. In addition, since the porosity of the sheet was too low, the protrusions were crushed by the sheet, and thus some of the protrusions were transferred to the sheet during unwinding.

As is clear from the results shown in Tables 1 to 5, the separation membrane elements of Examples 1 to 20 of the present invention obtain a sufficient amount of permeated water having a high desalination rate even when operated for a long time. It can be said that it has stable separation performance.

The separation membrane element of the present invention can be particularly suitably used for brine or seawater desalination.

DESCRIPTION OF SYMBOLS 1 Separation membrane 11 Envelope-shaped membrane 2 Separation membrane

2a Separation membrane

2b Separation membrane 2c Separation membrane 21 Supply side surface 21a Supply side surface 21b Supply side surface 21c Supply side surface 22 Permeation side surface 22a Permeation side surface 22b Permeation side surface 22c Permeation side surface 201 Base material 202 Porous support layer 203 Separation functional layer 31 Permeation side flow path material 32 Supply side flow path material 301 Protrusion 302 Sheet 303 Band-like region 4 Membrane leaf 5 Permeation side flow path 6 Water collecting pipe 7 Separation membrane 71 Supply side surface 72 Permeation side surface 81 Exterior body 82 Porous member 91 End plate (no hole)
92 End plate (with holes)
100 Separation Membrane Element a Separation Membrane (Leaf) Length b Permeation-side Channel Material Width Distance c Permeation-side Channel Material Height d Permeation-side Channel Material Width e Permeation-side Channel Material Length Interval f Length of permeate side channel material R2 Region including from the beginning to the end of permeate side channel material arranged from the inner side to the outer side in the winding direction in the separation membrane R3 Permeate side at the outer end in the winding direction of the separation membrane Region where no flow path material is provided L1 Total length of separation membrane (length a)
L2 Length of region R2 L3 Length of region R3 100A Separation membrane element (first form)
100B separation membrane element (second form)
100C separation membrane element (third form)
101 Raw water 102 Permeated water 103 Concentrated water

Claims

A separation membrane having a supply-side surface and a permeation-side surface and forming a separation membrane pair by being arranged so that the permeation-side surfaces face each other;
A permeation-side flow path member provided between the permeation-side surfaces of the separation membrane and having a gap and a plurality of protrusions provided on the sheet;
The protrusion contains a resin, and a part of the resin is impregnated in the sheet,
A band-like region not provided with the protrusions is provided at both end portions in the width direction of the sheet,
In the separation membrane pair, a separation membrane element is sealed between the permeation side surfaces of the separation membrane with an adhesive via the band-like region.
2. The separation membrane element according to claim 1, wherein a width of the belt-like region is wider than an interval between the plurality of protrusions in the width direction of the sheet.
The separation membrane element according to claim 1 or 2, wherein a width of the belt-like region is 0.25 mm or more and 70 mm or less.
The separation membrane element according to any one of claims 1 to 3, wherein the sheet has a thickness of 0.03 mm or less.
The separation membrane element according to any one of claims 1 to 4, wherein the thickness of the sheet is 0.3 mm or more and 0.4 mm or less, and the porosity of the sheet is 30% or more.
The separation membrane element according to any one of claims 1 to 5, wherein the thickness of the sheet is 0.02 mm or more and 0.25 mm or less, and the porosity of the sheet is 90% or less.
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 (H0 = H1 + c) is 0.05 to 0.7. Item 7. The separation membrane element according to any one of Items 1 to 6.
The ratio (c / H0) of the height c of the projections to the sum H0 of the sheet thickness H1 and the height c of the projections (H0 = H1 + c) is 0.05 to 0.13, and The separation membrane element according to claim 7, wherein the porosity of the sheet is 30% or more and 90% or less.
The ratio (c / H0) of the height c of the projections to the sum H0 (H0 = H1 + c) of the thickness H1 of the sheet and the height c of the projections exceeds 0.13 and is 0.7 or less. The separation membrane element according to claim 7, wherein the porosity of the sheet is 20% or more and 80% or less.
The separation membrane element according to any one of claims 1 to 9, wherein the protrusion is continuous in a direction perpendicular to a longitudinal direction of the water collecting pipe.