JP5981300B2 - Separation membrane support and method for producing the same - Google Patents

Description

  The present invention relates to a separation membrane support used as a support for a separation membrane such as a separation membrane for seawater desalination and a separation membrane for concentration concentration, etc., and relates to a separation membrane support excellent in texture and strength.

  Membrane technology is applied to water treatment in recent years in many cases. For example, microfiltration membranes and ultrafiltration membranes are used for water treatment at water purification plants, and reverse osmosis membranes are used for desalination of seawater. Also, reverse osmosis membranes and nanofiltration membranes are used for the treatment of semiconductor manufacturing water, boiler water, medical water, laboratory pure water, and the like. Furthermore, a membrane separation activated sludge method using a microfiltration membrane or an ultrafiltration membrane is also applied to the treatment of sewage wastewater.

  These separation membranes are roughly classified into flat membranes and hollow fiber membranes according to their shapes, and flat membranes formed mainly from synthetic polymers are generally poor in mechanical strength with membranes having a separation function. It is often used by being fixed and integrated with a support such as a woven fabric. In the case of a semipermeable membrane such as a reverse osmosis membrane, which is often used under high pressure, the support is required to have high mechanical strength in order to improve the durability of the separation membrane. Even in separation membranes for sewage treatment applied to the sludge process, inorganic substances such as sand, sludge, and other solids collide violently during use, or supply oxygen to activated sludge and clogging prevention. Since the bubbles caused by the aeration operation performed on the surface collide violently with the membrane surface, it is important that the support has a high mechanical strength that can sufficiently withstand such an impact.

  Conventionally, as such a separation membrane support, a double structure of a surface layer having a large opening and a large surface roughness using a thick fiber and a back layer having a small structure and a small opening using a thin fiber A separation membrane support characterized in that it is made of a non-woven fabric having a multilayer structure based on (for example, see Patent Document 1), and at least the surface layer on the membrane-forming side has a fiber specific surface area larger than that of a circular cross-section fiber There is known a separation membrane support characterized by comprising a fiber mainly composed of a modified cross-section fiber (for example, see Patent Document 2).

A polyester wet nonwoven fabric has also been proposed for use as a separation membrane support (see, for example, Patent Document 3 and Patent Document 4). Such a polyester-based wet nonwoven fabric is composed of a polyester main fiber and a polyester unstretched binder fiber, and is finally calendered. Such a polyester-based wet nonwoven fabric has a good texture because it has been wet-made.
However, a separation membrane support excellent in texture and strength has not been proposed so far.

Japanese Patent Publication No. 4-21526 JP 11-347383 A JP 2002-95937 A Japanese Patent Laid-Open No. 10-225630

  The present invention provides a separation membrane support that is used as a support for a separation membrane such as a separation membrane for seawater desalination and a separation membrane for concentration concentration, etc., and provides a separation membrane support that is excellent in texture and strength. is there.

  As a result of diligent investigations to achieve the above-mentioned problems, the present inventors have made the separation membrane support a multilayer structure, of which two layers are composed of fibers having a specific fiber diameter and have a specific basis weight, The inventors have found that a separation membrane support excellent in strength can be obtained, and have made further investigations and completed the present invention.

Thus, according to the present invention, “from a wet nonwoven fabric or a spunbonded nonwoven fabric having a multilayer structure, comprising thermoplastic fibers having a fiber diameter of 2 to 15 μm and a basis weight of 50 to 100 g / m ^2. A first layer comprising a thermoplastic main fiber having a fiber diameter of 2 to 15 μm and a binder fiber having a fiber diameter of 7 to 15 μm and a wet nonwoven fabric having a basis weight of 35 to 60 g / m ^2. A separation membrane support comprising the separation membrane support.
Is provided.

In that case, it is preferable that the thermoplastic fiber contained in the first layer is a polyester fiber. Moreover, it is not preferable thermoplastic main fibers included in the second layer is a polyester fiber. Moreover , it is preferable that the calendar process is given.

  According to the present invention, there is provided a separation membrane support that is used as a support for a separation membrane such as a separation membrane for seawater desalination and a separation membrane for concentration concentration, etc., and has a superior texture and strength. The

First, the separation membrane support of the present invention includes thermoplastic fibers having a fiber diameter of 2 to 15 μm (preferably 7 to 14 μm) and a basis weight of 40 to 100 g / m ² (preferably 41 to 70 g / m ² ). A first layer made of a non-woven fabric of Such a first layer is a layer mainly contributing to the strength of the separation membrane support.

  In the first layer, when the fiber diameter of the thermoplastic fiber is smaller than 2 μm, the strength of the separation membrane support may be lowered, which is not preferable. Conversely, when the fiber diameter of the thermoplastic fiber is larger than 15 μm, the texture of the separation membrane support may be lowered, which is not preferable. When the cross-sectional shape of the single fiber is an atypical cross section other than the round cross section, the diameter of the circumscribed circle is the fiber diameter. Such a thermoplastic fiber may be a long fiber or a short fiber.

  Examples of the thermoplastic fiber contained in the first layer include fibers comprising at least one component such as a polyester polymer, a polyamide polymer, a polyolefin polymer, or a mixture or copolymer thereof. However, polyester fibers are preferred for obtaining a separation membrane support having more excellent mechanical strength, heat resistance, water resistance and chemical resistance.

  Examples of such polyester fibers include polyethylene terephthalate, polybutylene terephthalate, polytrimethylene terephthalate, polyhexamethylene terephthalate, poly-1,4-dimethylcyclohexane terephthalate, polypivalolactone and copolymers thereof, or polylactic acid and stereo. Preferred examples include fibers obtained by spinning and drawing an aliphatic polyester such as complex polylactic acid by a conventional method. The polyester may be material recycled or chemically recycled polyester. Furthermore, the polyester obtained using the catalyst containing the specific phosphorus compound and titanium compound which are described in Unexamined-Japanese-Patent No. 2004-270097 and 2004-21268 may be sufficient. In the polymer, a fine pore forming agent, a cationic dye dyeing agent, an anti-coloring agent, a heat stabilizer, a fluorescent whitening agent, a matting agent, a coloring agent may be added as necessary within the range not impairing the object of the present invention. 1 type, or 2 or more types of an agent, a hygroscopic agent, and inorganic fine particles may be contained.

Further, if the basis weight is less than 40 g / m ² in the first layer, it is not preferable because the layer is so thin that it may not be able to withstand actual use under high pressure. On the other hand, if the basis weight is larger than 100 g / m ² , a compact separation membrane support may not be obtained, which is not preferable.

The separation membrane support of the present invention includes not only the first layer but also thermoplastic main fibers (sometimes referred to simply as “main fibers”) and fibers having a fiber diameter of 2 to 15 μm (preferably 7 to 14 μm). A second layer is also included, which includes a binder fiber having a diameter of 7 to 15 μm (preferably 10 to 14 μm) and a nonwoven fabric having a basis weight of 10 to 60 g / m ² (preferably 10 to 40 g / m ² ). Such a second layer is a layer mainly contributing to the formation of the separation membrane support.

  In the second layer, if the fiber diameter of the thermoplastic main fiber is smaller than 2 μm, the porosity is lowered and liquid permeability may be lowered. On the contrary, when the fiber diameter of the thermoplastic main fiber is larger than 15 μm, the texture may be lowered, which is not preferable. On the other hand, when the fiber diameter of the binder fiber is smaller than 7 μm, the porosity is lowered and liquid permeability may be lowered, which is not preferable. On the contrary, if the fiber diameter of the binder fiber is larger than 15 μm, the texture may be lowered, which is not preferable. When the cross-sectional shape of the single fiber is an atypical cross section other than the round cross section, the diameter of the circumscribed circle is the fiber diameter. Such a thermoplastic fiber may be a long fiber or a short fiber.

Further, in the second layer, when the basis weight is less than 10 g / m ² , the thickness unevenness of the support is remarkable, and there are many portions where the back-through easily occurs, and the strength may be lowered. Absent. On the other hand, if the basis weight is larger than 60 g / m ² , a compact separation membrane support may not be obtained.

The kind of thermoplastic main fiber contained in the second layer may be the same as the kind of thermoplastic fiber contained in the first layer.
Examples of the binder fibers contained in the second layer include core-sheath polyester composite fibers and unstretched fibers made of polyester.

  Examples of the core-sheath type polyester composite fiber include those in which a heat-fusion component is disposed in the sheath component and polyester such as polyethylene terephthalate is disposed in the core component, and the former is exposed on the fiber surface. As a weight ratio, the range of 30/70 to 70/30 is appropriate for the former and the latter. In this core-sheath type, the core portion may be concentric or eccentric. In particular, an eccentric shape is preferable because spiral crimps are manifested. The cross-sectional shape of the fiber may be hollow, solid, or atypical.

  Here, as the polymer to be arranged as the heat fusion component, polyurethane elastomer, polyester elastomer, inelastic polyester polymer and copolymer thereof (copolymer polyester polymer), polyolefin polymer and copolymer thereof, A polyvinyl alcohol-type polymer etc. can be mentioned. Of these, a copolyester polymer and a polyolefin polymer are preferable.

  Examples of the polyurethane elastomer include low-melting-point polyols having a molecular weight of about 500 to 6,000, such as dihydroxy polyether, dihydroxy polyester, dihydroxy polycarbonate, dihydroxy polyester amide, and the like, and organic diisocyanates having a molecular weight of 500 or less, such as p, p'- Diphenyl methane diisocyanate, tolylene diisocyanate, isophorone diisocyanate hydrogenated diphenyl methane isocyanate, xylylene isocyanate, 2,6-diisocyanate methyl caproate, hexamethylene diisocyanate and the like, and chain extenders having a molecular weight of 500 or less, such as glycol amino alcohol Alternatively, it is a polymer obtained by reaction with triol.

  Among these polymers, particularly preferred is a polyurethane using polytetramethylene glycol, poly-ε-caprolactam or polybutylene adipate as a polyol. Examples of the organic diisocyanate in this case include p, p'-bishydroxyethoxybenzene and 1,4-butanediol.

  Polyester elastomers include polyether ester copolymers obtained by copolymerizing thermoplastic polyester as a hard segment and poly (alkylene oxide) glycol as a soft segment, and more specifically, terephthalic acid, isophthalic acid, phthalate. Alicyclic dicarboxylic acids such as acid, naphthalene-2,6-dicarboxylic acid, naphthalene-2,7-dicarboxylic acid, diphenyl-4,4′-dicarboxylic acid, 1,4-cyclohexanedicarboxylic acid, succinic acid, oxalic acid , At least one dicarboxylic acid selected from aliphatic dicarboxylic acids such as adipic acid, sebacic acid, dodecanedioic acid and dimer acid, or ester-forming derivatives thereof, 1,4-butanediol, ethylene glycol trimethylene glycol Tetramethylene glyco Alicyclic diols such as diol, pentamethylene glycol, hexamethylene glycol neopentyl glycol, decamethylene glycol or 1,1-cyclohexanedimethanol, 1,4-cyclohexanedimethanol, tricyclodecane methanol, or At least one diol component selected from these ester-forming derivatives and the like, and polyethylene glycol, poly (1,2- and 1,3-polypropylene oxide) glycol having an average molecular weight of about 400 to 5,000, poly At least one of poly (alkylene oxide) glycols such as (tetramethylene oxide) glycol, a copolymer of ethylene oxide and propylene oxide, and a copolymer of ethylene oxide and tetrahydrofuran Can be exemplified et constituted terpolymer.

  In particular, from the viewpoint of adhesiveness, temperature characteristics, and strength, a block copolymer polyether ester having polybutylene terephthalate as a hard component and polyoxybutylene glycol as a soft segment is preferable.

  In this case, the polyester portion constituting the hard segment is polybutylene terephthalate in which the main acid component is terephthalic acid and the main diol component is a butylene glycol component. Of course, a part of this acid component (usually 30 mol% or less) may be substituted with another dicarboxylic acid component or an oxycarboxylic acid component, and similarly a part of the glycol component (usually 30 mol% or less). May be substituted with a dioxy component other than the butylene glycol component. Further, the polyether portion constituting the soft segment may be a polyether substituted with a dioxy component other than butylene glycol.

  Copolyester polymers include aliphatic dicarboxylic acids such as adipic acid and sebacic acid, aromatic dicarboxylic acids such as phthalic acid, isophthalic acid and naphthalenedicarboxylic acid and / or fats such as hexahydroterephthalic acid and hexahydroisophthalic acid. A co-polymer containing a predetermined number of cyclic dicarboxylic acids and aliphatic or alicyclic diols such as diethylene glycol, polyethylene glycol, propylene glycol, and paraxylene glycol, with addition of oxyacids such as parahydroxybenzoic acid as desired. Polymerized esters and the like can be mentioned. For example, polyester obtained by adding and copolymerizing isophthalic acid and 1,6-hexanediol to terephthalic acid and ethylene glycol is preferable. Such polyester may be amorphous or crystalline.

When unstretched fibers made of polyester are used as the binder fibers, polyesters such as polyethylene terephthalate, polytrimethylene terephthalate, and polybutylene terephthalate are spun at a spinning speed of 800 to 1,200 m / min. And unstretched fibers. Preferably, it is an undrawn fiber made of polyethylene terephthalate or polytrimethylene terephthalate. An unstretched fiber made of polyethylene terephthalate or polytrimethylene terephthalate is usually o-chlorophenol, a polymer having an intrinsic viscosity measured at 35 ° C. of 0.80 to 1.00 dL / g from a spinneret of 240 to 280 ° C. It is obtained by discharging and winding at 800 to 1,200 m / min, preferably 900 to 1,100 m / min. This unstretched fiber usually has a birefringence of 0.01 to 0.05 and a melting point of 220 to 230 ° C. and is useful as a binder fiber.
In addition, you may use together the said core-sheath-type polyester composite fiber and unstretched polyester fiber as binder fiber.

  In the second layer, the weight ratio of the thermoplastic main fiber to the binder fiber is preferably (thermoplastic main fiber / binder fiber) 90/10 to 50/50. If the thermoplastic main fiber exceeds 90% by weight (the binder fiber is less than 10% by weight), the number of adhesion points constituting the form of the nonwoven fabric becomes too small, and the strength may be insufficient. On the other hand, if the thermoplastic main fiber is less than 50% by weight (the binder is greater than 50% by weight), the number of adhesion points becomes excessive, and the nonwoven fabric itself may become hard.

  The separation membrane support of the present invention has a multilayer structure and includes the first layer and the second layer. In the case of a single layer, there is a possibility that it is difficult to achieve both the texture and the strength. The number of layers is preferably 2 to 5 layers (particularly preferably 2 layers, that is, the first layer and the second layer). Two or more layers are preferable because sufficient uniformity can be obtained by improving the weight per unit area of the micro area as compared with the case of a single layer. Moreover, if it is five layers or less, the wrinkles which enter at the time of lamination | stacking, and the peeling between layers can be suppressed, and it is preferable.

  In the separation membrane support of the present invention, a layer composed of a woven fabric, a knitted fabric, a net or the like may be included, but it is preferable that all the layers are composed of a nonwoven fabric. By using laminated non-woven fabric, the texture of the micro area becomes uniform, and by forming the laminated interface, the penetration of polymer solution is reduced by suppressing excessive penetration during casting of polymer solution. It can be suitably used as a membrane support.

Here, as a form of the combination of the nonwoven fabrics, it is preferable that at least one of the multilayers is a spunbonded nonwoven fabric from the viewpoint of mechanical strength, dimensional stability, and cost. Moreover, it is preferable that at least 1 layer is a wet nonwoven fabric from the point of formation.
Moreover, it is preferable that the surface of the separation membrane support is smooth at least on the side on which the membrane is formed from the viewpoint of film forming properties. The “smooth surface” means a surface without intentional unevenness by an engraving roll or the like, and means a surface treated by a flat roll or the like, for example.

  The method for producing the separation membrane support of the present invention may be a method in which a nonwoven fabric or the like is produced by a conventional method, then laminated, and if necessary, heat treatment such as calendering is performed. For example, in the case of a wet non-woven fabric, there is no problem even if it is a normal long net paper machine, a short net paper machine, a round net paper machine, or a combination of a plurality of these to make a multi-layer paper.

  As the heat treatment process, either a Yankee dryer or an air-through dryer is possible after the paper making process. Moreover, you may give calendar / embossing, such as a metal / metal roller, a metal / paper roller, and a metal / elastic roller. In particular, when calendering (processing of passing a nonwoven fabric between two rolls) is applied to the nonwoven fabric, the sheath portion of the core-sheath polyester composite fiber, which is a binder fiber, is melted by heat, and the thermoplastic main fiber is heated by the binder fiber. Since it adhere | attaches, the intensity | strength of a nonwoven fabric improves and it is preferable.

Here, in the heat calender treatment, the temperature is usually 150 to 230 ° C., preferably 180 to 200 ° C., and the pressure is 80 to 240 kg / cm, preferably 120 to 180 kg / cm.
Since the separation membrane support thus obtained is excellent in texture and strength, it is preferably used as a support for a separation membrane for seawater desalination, a separation membrane for concentration concentration, and the like.

Next, although the Example and comparative example of this invention are explained in full detail, this invention is not limited by these. In addition, each measurement item in an Example was measured with the following method.
(1) Average tensile strength (average fracture length)
The test was carried out based on JIS P8113 (paper and board tensile strength test method), and the average value of tensile strength in the MD direction and CD direction was calculated by rounding off the second decimal place.
(2) Weight per unit It was carried out based on JIS P8124 (Metric basis weight measurement method for paper), and was calculated by rounding off the first decimal place.
(3) Melting point (° C)
Using a differential scanning calorimeter manufactured by Perkin Elma Co., Ltd., measurement was performed under a nitrogen atmosphere under a temperature rising rate of 20 ° C./min, and the temperature giving an extreme value in the obtained melting endotherm curve was defined as the melting point. Further, for a resin whose melting endotherm curve does not show an extreme value in a differential scanning calorimeter, the resin was heated on a hot plate, and the temperature at which the resin was completely melted by microscopic observation was taken as the melting point.
(4) Fiber diameter (μm)
Ten small sample samples are taken at random from the nonwoven fabric, photographed with a scanning electron microscope at a magnification of 500 to 3000 times, and 10 from each sample, the diameter of a total of 100 single fibers is measured, and the average value thereof Was calculated by rounding off the first decimal place.
(5) Strength When the total average breaking length of each layer was 15 km or more, it was evaluated as ◯ (pass), and when it was less than 15 km, it was determined as x (fail).
(6) Texture The texture of the surface of the finished sample was visually judged as two levels: ○ (pass) and x (fail).

[Example 1]
Using polyethylene terephthalate (PET), the spunbond method is used to extrude the filament group at the spinning temperature of 300 ° C toward the collection net surface that moves, spins at a spinning speed of 3500 m / min, and charges about 3 µC / g by corona charging. Then, the thermoplastic resin long fiber web was prepared on a collection net to obtain a first layer made of a spunbonded nonwoven fabric. The fiber diameter was adjusted by changing the discharge amount.
On the other hand, a polyethylene terephthalate (PET) thermoplastic main fiber having a fiber diameter of 8 μm and a fiber length of 5 mm and a binder fiber made of unstretched polyethylene terephthalate having a fiber diameter of 12 μm and a fiber length of 5 mm are 60/40 weight. After mixing and stirring at a ratio, using a hand paper machine (manufactured by Kumagai Riki Kogyo Co., Ltd., model number: No. 2555, standard square sheet machine, the same applies hereinafter), a wet non-woven fabric with a basis weight of 35 g / m ² was made, and then a dryer ( Using Kumagai Riki Kogyo, model number: No. 2575-II, rotary dryer (high temperature type)), the drying treatment was performed at 180 ° C. for 1 minute. Thereafter, calendering (210 ° C. × 50 kg (490 N) / cm) made of metal / metal was applied to obtain a second layer made of a wet nonwoven fabric.
Next, the first layer and the second layer were superposed and thermally bonded with a flat roll and a calender roll to obtain a separation membrane support. The evaluation results are shown in Table 1.
Subsequently, the separation membrane support for seawater desalination and the separation membrane support for concentration concentration and the like were obtained using the separation membrane support.

[Example 2]
Example 1 was the same as Example 1 except that the fiber diameter of the fibers constituting the first layer was 8 μm and the basis weight of the first layer was 53 g / m ² . The evaluation results are shown in Table 1.
Subsequently, the separation membrane support for seawater desalination and the separation membrane support for concentration concentration and the like were obtained using the separation membrane support.

[Example 3]
In Example 1, a polyethylene terephthalate (PET) main fiber having a fiber diameter of 13 μm and a fiber length of 5 mm and a binder fiber made of unstretched polyethylene terephthalate having a fiber diameter of 12 μm and a fiber length of 5 mm (the former / the latter) ) The same procedure as in Example 1 was carried out except that a first layer made of a wet nonwoven fabric with a basis weight of 50 g / m ² was obtained by mixing and papermaking at a weight ratio of 60/40. The evaluation results are shown in Table 1.
Subsequently, the separation membrane support for seawater desalination and the separation membrane support for concentration concentration and the like were obtained using the separation membrane support.

[Example 4]
Example 2 was the same as Example 2 except that the fiber diameter of the main fibers contained in the second layer was changed to 13 μm and the fiber length was changed to 5 mm. The evaluation results are shown in Table 1.
Subsequently, the separation membrane support for seawater desalination and the separation membrane support for concentration concentration and the like were obtained using the separation membrane support.

[Example 5]
In Example 2, the binder fiber contained in the second layer is made of crystalline core-sheath binder fiber (sheath component: 80/20 mol% of terephthalic acid and isophthalic acid, ethylene glycol and tetramethylene glycol 50/50 mol). % Copolymerized polyester, core component: polyethylene terephthalate). At that time, the core-sheath ratio was 50/50 by weight. The dryer temperature was changed to 150 ° C. × 2 minutes, and the same procedure as in Example 2 was performed except that calendaring (180 ° C. × 50 kg (490 N) / cm) was performed. The evaluation results are shown in Table 1.
Subsequently, the separation membrane support for seawater desalination and the separation membrane support for concentration concentration and the like were obtained using the separation membrane support.

[Comparative Example 1]
In Example 1, when the second layer is formed, PET is used and extruded by a spunbond method at a spinning temperature of 300 ° C. toward the collection net surface that moves the filament group, and is spun at a spinning speed of 3500 m / min. Then, it is charged with about 3 μC / g by corona charging, fully opened, a thermoplastic resin long fiber web is prepared on a collection net, and a condition that matches the target of the fiber diameter is taken, and the basis weight is 53 g / m ^2. The procedure was the same as in Example 1 except that. The evaluation results are shown in Table 1.
Subsequently, the separation membrane support for seawater desalination and the separation membrane support for concentration concentration and the like were obtained using the separation membrane support.

[Comparative Example 2]
In Example 2, the same procedure as in Example 2 was performed except that the fiber diameter of the main fiber contained in the second layer was 18 μm and the fiber length was 5 mm. The evaluation results are shown in Table 1.
Subsequently, the separation membrane support for seawater desalination and the separation membrane support for concentration concentration and the like were obtained using the separation membrane support.

[Comparative Example 3]
In Example 2, the same procedure as in Example 2 was performed, except that the fiber diameter of the main fiber constituting the first layer was changed to 13 μm, the fiber length was changed to 5 mm, and the basis weight was changed to 32 g / m ² . The evaluation results are shown in Table 1.
Subsequently, the separation membrane support for seawater desalination and the separation membrane support for concentration concentration and the like were obtained using the separation membrane support.

[Comparative Example 4]
In Comparative Example 3, the binder fiber contained in the second layer was changed to a crystalline core-sheath binder fiber (sheath component: 80/20 mol% of terephthalic acid and isophthalic acid, ethylene glycol and tetramethylene glycol 50/50 mol). % Copolymerized polyester, core component: polyethylene terephthalate). At that time, the core-sheath ratio was 80/20 by weight ratio. Moreover, after changing dryer temperature into 150 degreeC x 2 minutes, it carried out similarly to the comparative example 3 except implementing calendar processing (180 degreeC x 50 kg (490N) / cm). The evaluation results are shown in Table 1.
Subsequently, the separation membrane support for seawater desalination and the separation membrane support for concentration concentration and the like were obtained using the separation membrane support.

  According to the present invention, a separation membrane support that is used as a support for a separation membrane such as a separation membrane for seawater desalination or a separation membrane for concentration concentration, and a separation membrane support excellent in texture and strength can be obtained. The industrial value is extremely large.

Claims (4)

A separation membrane support having a multilayer structure,
A first layer made of a wet nonwoven fabric or a spunbonded nonwoven fabric, comprising thermoplastic fibers having a fiber diameter of 2 to 15 μm and a basis weight of 50 to 100 g / m ² , and thermoplastic main fibers and fibers having a fiber diameter of 2 to 15 μm A separation membrane support comprising a second layer made of a wet nonwoven fabric having a binder fiber having a diameter of 7 to 15 µm and a basis weight of 35 to 60 g / m ² .   The separation membrane support according to claim 1, wherein the thermoplastic fibers contained in the first layer are polyester fibers.   The separation membrane support according to claim 1 or 2, wherein the thermoplastic main fibers contained in the second layer are polyester fibers. The manufacturing method of the separation-membrane support body in any one of Claims 1-3 to which the calendar process is given.