JP5902886B2 - Method for producing semipermeable membrane support - Google Patents

Description

The present invention relates to a method for producing a semipermeable membrane support.

  Semipermeable membranes are widely used in the fields of desalination of seawater, water purification, food concentration, wastewater treatment, production of ultrapure water for medical use, semiconductor cleaning, and the like. The semipermeable membrane is made of a synthetic resin such as a cellulose resin, a polysulfone resin, a polyacrylonitrile resin, a fluorine resin, a polyester resin, a polyamide resin, or a polyimide resin. However, since the semipermeable membrane itself is inferior in mechanical strength, a semipermeable membrane is provided on one side (hereinafter referred to as “semipermeable membrane application surface”) of a semipermeable membrane support made of a fiber base material such as a nonwoven fabric or a woven fabric. It is used in the form.

  The semipermeable membrane is provided on the semipermeable membrane support by dissolving the above-mentioned synthetic resin such as polysulfone resin in an organic solvent, preparing a semipermeable membrane solution, and then adding the semipermeable membrane solution to the semipermeable membrane. A method of coating on a support is widely used. And in order to perform filtration efficiently, a spiral type semipermeable membrane element is formed, and a semipermeable membrane module is further assembled (for example, refer to patent documents 1).

  In order to obtain a high filtration flux and filtration performance, the semipermeable membrane surface has few irregularities, no lateral bending or wrinkling occurs when the semipermeable membrane is formed, and the semipermeable membrane is uniform on the semipermeable membrane support. It is necessary to be provided with an appropriate thickness. Therefore, excellent smoothness is required for the semipermeable membrane application surface of the semipermeable membrane support. And in order to obtain favorable filtration performance, it is necessary to be excellent also in the adhesiveness of a semipermeable membrane and a semipermeable membrane support body. Further, when assembling the semipermeable membrane module, there is a step of bonding the semipermeable membrane non-coated surfaces (hereinafter referred to as “non-coated surfaces”), which are opposite to the semipermeable membrane coated surfaces, using an adhesive. Therefore, it is also required that the adhesion between the non-coated surfaces is excellent. Furthermore, it is required that the semipermeable membrane solution does not penetrate the non-coated surface. This is because when this breakthrough occurs, the thickness of the semipermeable membrane becomes non-uniform and the adhesion between the non-coated surfaces decreases.

  As a semipermeable membrane support, a nonwoven fabric comprising a main synthetic fiber and a binder synthetic fiber, manufactured by a wet papermaking method, and subjected to a hot-pressure treatment has been proposed. For example, a non-woven fabric with a multilayer structure based on a double structure consisting of a surface layer with a large surface roughness (thick fiber layer) using thick fibers and a back layer (thin fiber layer) with a dense structure using thin fibers. A semipermeable membrane support has been proposed (see, for example, Patent Document 2). Specifically, a semipermeable membrane support having a thick fiber layer as a semipermeable membrane application surface and a thin fiber layer as a non-application surface and a thin fiber layer sandwiched between the thick fiber layers, the semipermeable membrane application surface and the non-application surface A semipermeable membrane support is described in which both are thick fiber layers. However, since thick fibers are used on the semipermeable membrane application surface, the adhesion between the semipermeable membrane and the semipermeable membrane support is improved, but there is a problem that the smoothness is low. In addition, because thick fibers are used, the semipermeable membrane solution penetrates into the semipermeable membrane support, and a large amount of semipermeable membrane solution is required to obtain the desired semipermeable membrane thickness. There was a problem of becoming. Moreover, in the former, since the thin fiber was used for the non-application surface, there also existed a problem that the adhesiveness of non-application surfaces was not good.

  A semipermeable membrane support made of a nonwoven fabric having a single layer structure in which the surface roughness of the semipermeable membrane application surface is made larger than that of the non-application surface is also disclosed, but this semipermeable membrane support is also smooth on the semipermeable membrane application surface. There was a problem in the property, the uniformity of the semipermeable membrane, and the adhesion between the non-coated surfaces (for example, see Patent Document 3). Moreover, in the semipermeable membrane support of Patent Document 3, the tensile strength ratio in the papermaking flow direction (longitudinal direction, MD) and the width direction (transverse direction, CD) is defined. This is intended to prevent the bending in the width direction. In order to keep the tensile strength ratio in the paper flow direction and the width direction within a specific range, it is necessary to adjust the concentration of the raw material dispersion, the water flow speed, the wire speed of the inclined wire mesh, the angle of inclination, etc. in the paper making process. is there. Moreover, even if the tensile strength ratio in the paper flow direction and the width direction is adjusted, it is difficult to suppress the width shrinkage of the semipermeable membrane support that occurs in the hot water washing and drying part when forming the semipermeable membrane. It has not been possible to solve the occurrence of the occurrence of bending and the occurrence of bending. Furthermore, the semipermeable membrane support of Patent Document 3 describes that when the content of the binder synthetic fiber is increased, the smoothness is increased, but at the same time, the air permeability becomes too small, and the filtration during filtration is performed. The problem arises that the flux decreases.

  Further, Patent Document 3 proposes a method for adjusting the air permeability and pore size of the semipermeable membrane support for the purpose of improving the adhesion between the semipermeable membrane and the semipermeable membrane support and preventing the back-through. . However, the air permeability according to JIS L1096 is calculated on the basis of the amount of air passing from one side of the semipermeable membrane support through the inside of the semipermeable membrane support to another side. This does not accurately reflect the penetration of the semipermeable membrane solution applied to the surface of the film application surface to the non-application surface. Therefore, when the semipermeable membrane solution is applied to the semipermeable membrane support having the air permeability in the range shown in Patent Document 3, the semipermeable membrane solution penetrates to the non-coated surface of the semipermeable membrane support, When semi-permeable membrane modules are produced by attaching semi-permeable membrane support non-coated surfaces to each other, there may be a problem that the adhesive strength is reduced and the filtration performance is remarkably reduced. Further, as a method of reducing the air permeability of the support, a method of reducing the fiber diameter of the fibers constituting the semipermeable membrane support has been proposed, but also in this case, the smoothness of the non-coated surface is increased, There was a problem that the adhesiveness between the non-coated surfaces decreased.

  In addition, the average pore size by the bubble point method based on JIS K3832 described in Patent Document 3 is such that a gas is ejected in a pressurized state from the lower surface of a semipermeable membrane support filled with a liquid whose surface tension is known. This is a method for obtaining the pore size from the change in pressure of the gas when the gas passes through the upper surface of the film, but also in this case, the penetration of the semipermeable membrane solution applied to the surface of the semipermeable membrane applied surface to the non-coated surface It is not an accurate reflection. Therefore, when a semipermeable membrane solution is applied to a semipermeable membrane support having a pore size in the range shown in Patent Document 3, it is difficult to completely prevent the back-through.

  Fiber for making paper (pulp), which is a natural fiber, as a semipermeable membrane support that can be provided at low cost while preventing the back-through of the semipermeable membrane solution and improving the adhesion between the semipermeable membrane and the semipermeable membrane support A semipermeable membrane supporting body mainly composed of the above has been proposed. For example, a semipermeable membrane support having a two-layer structure comprising an upper layer containing main synthetic fibers and binder synthetic fibers, and a lower layer containing paper-making fibers (pulp) and binder synthetic fibers (see, for example, Patent Document 4) , A semipermeable membrane support having a two-layer structure comprising an upper layer containing papermaking fibers (pulp) and binder synthetic fibers, and a lower layer containing main synthetic fibers and binder synthetic fibers (see, for example, Patent Document 5), A two-layered semipermeable membrane support comprising upper and lower layers containing a papermaking fiber (pulp) and a binder synthetic fiber has been proposed (for example, see Patent Document 6). However, since the non-coated surface layer has a denser structure than the semi-permeable film coated surface layer, there is a problem with the semi-permeable film coating surface uniformity and smoothness, and the non-coated surface adhesion property. It was a membrane support. In addition, when papermaking fibers (pulp) are used, mold and fungi grow, so that there is a fatal problem for the semipermeable membrane support that clean water cannot be produced.

  A semipermeable membrane support described in Patent Documents 2 to 6 in a semipermeable membrane support comprising a non-woven fabric that contains a main synthetic fiber and a binder synthetic fiber, is manufactured by a wet papermaking method, and is heat-pressed. Contrary to the body, a semipermeable membrane support in which the density of the non-coated surface is lower than the density of the semipermeable membrane coated surface and the semipermeable membrane coated surface is smoother than the non-coated surface has also been proposed ( For example, see Patent Document 7). However, a semipermeable membrane is provided so as to reach the concave portion of the semipermeable membrane support having a concave portion on the non-coated surface, or the semipermeable membrane is formed through a hole formed on the semipermeable membrane coated surface. Since the semipermeable membrane is provided so as to reach the non-coated surface, there is a problem that the thickness of the semipermeable membrane is not uniform. In Patent Document 5, as a method for preventing the penetration of the semipermeable membrane solution to the non-coated surface, the average density of the region from the non-coated surface to 50% of the total thickness is 50% of the total thickness from the coated surface. The method of making it in the range of 5-90% with respect to the average density of the area | region until is also shown. However, in this method, in the semipermeable membrane support having the characteristic that the absolute value of the average density in the region from the semipermeable membrane application surface side to 50% of the total thickness is low, the back-through of the semipermeable membrane solution is prevented. There was a problem that we couldn't.

As a semipermeable membrane support that improves the dimensional stability when subjected to tensile stress, has a smooth semipermeable membrane application surface, no back-through, and excellent semipermeable membrane adhesion, it has a longitudinal length of 5% when stretched. Semipermeable membrane support made of non-woven fabric having an average value of direction (MD) and transverse direction (CD) tear lengths of 4.0 km or more and an air permeability of 0.2 to 10.0 cc / cm ² · sec Has been proposed (see, for example, Patent Document 8). This semipermeable membrane support is a nonwoven fabric having high strength and small elongation. Therefore, in order to produce this semipermeable membrane support, it is necessary to use a polyester fiber having a high birefringence (Δn) and a specific heat shrinkage stress. In addition, in order to increase the tearing length, it is necessary to increase the heat and pressure applied to the nonwoven fabric in the hot-pressure treatment process, improving the non-uniformity of the nonwoven fabric due to the tensile stress and partial unevenness of the fiber due to heat. Although there is an effect, excessive heat and pressure are applied in all the thickness direction of the nonwoven fabric, the binder synthetic fiber contained in the nonwoven fabric is excessively melted, and the voids are excessively reduced, and wrinkles are generated when a semipermeable membrane is applied. There was a problem to do. Moreover, further improvement was required for the smoothness of the semipermeable membrane application surface. In particular, Patent Document 8 is manufactured so as to equalize the smoothness of the semipermeable membrane application surface and the non-application surface, so the smoothness of the semipermeable membrane application surface and the semipermeable membrane and the semipermeable membrane support There is a problem that it is difficult to achieve compatibility with adhesiveness, and there is still a problem with respect to adhesiveness between non-coated surfaces.

  In order to improve the adhesion between the semipermeable membrane and the semipermeable membrane support, a semipermeable membrane support in which a modified cross-section fiber is included in the semipermeable membrane coated surface layer has also been proposed. When blended with a support, there is a problem that when the fibers are dispersed in water in the wet papermaking process, the fibers get caught in the convex portions and concave portions formed in the irregular cross-section fibers, and entanglement occurs, and uniform dispersion cannot be achieved. (For example, see Patent Document 9).

  By including polyacrylonitrile-based synthetic fiber in the semipermeable membrane support, the polyacrylonitrile-based synthetic fiber dissolves in the solvent used in the semipermeable membrane solution. A technique for improving the performance has been proposed (see, for example, Patent Document 10). However, depending on the solvent used for the semipermeable membrane solution, it may not melt. Even when a solvent to be melted is used, the time from the contact of the semipermeable membrane solution with the semipermeable membrane support to the transition to the water washing step is very short, and therefore improvement in adhesion cannot be expected.

  In order to improve the uniformity of the semipermeable membrane support so as not to cause back-through, the fiber slurry in which the synthetic fiber is dispersed in water is made into a non-woven fabric by wet paper making. The fiber concentration is 0.01 to 0.1% by mass, and a water-soluble polymer having a molecular weight of 5 million or more is added to the fiber slurry as a polymer viscosity agent, and 3 to 15% by mass based on the fiber mass. There has been proposed a method of making paper by containing (for example, see Patent Document 11). However, since the polymer viscosity agent is added excessively, the uniformity is increased, but the fiber slurry viscosity on the papermaking wire is increased, the dewaterability from the wire is decreased, and the production rate cannot be increased. Problems can arise. In addition, there has been a problem that the polymer adhesive remains on the surface of the fibers forming the semipermeable membrane support after paper making.

  Proposal of semi-permeable membrane support characterized in that it contains two types of main synthetic fibers with different fiber diameters and two types of binder synthetic fibers with different melting points, and changes the drying temperature of the wet papermaking method and the temperature of the hot pressing process. However, this is for the purpose of easily producing a semipermeable membrane support by a wet papermaking method. Adhesion between the semipermeable membrane and the semipermeable membrane support, adhesion between non-coated surfaces No consideration is given to the smoothness of the semipermeable membrane application surface, prevention of breakthrough, etc. (see, for example, Patent Documents 12 and 13).

  Moreover, in patent document 12 and 13, the binder synthetic fiber which consists of a core sheath type polyester composite fiber is used as a binder synthetic fiber. However, when a binder synthetic fiber composed of a core-sheath polyester composite fiber is used, the binder component is only the sheath portion, and therefore, the binder component is about ½ compared to the unstretched binder synthetic fiber. In some cases, adhesive strength could not be obtained.

  In this way, smoothness of the semipermeable membrane application surface, adhesion between the semipermeable membrane and the semipermeable membrane support, adhesion between non-application surfaces, prevention of back-through, prevention of lateral bending during semipermeable membrane formation and A semipermeable membrane support that satisfies all of the properties of preventing wrinkles and the like in a well-balanced manner has not been obtained. In particular, no consideration is given to the adhesion between non-coated surfaces in Patent Documents 1 to 13.

JP 2001-252543 A JP 60-238103 A JP 2002-95937 A JP 2009-178915 A JP 2009-240893 A JP 2009-240894 A JP 2003-245530 A Japanese Patent Laid-Open No. 10-225630 JP 11-347383 A JP 2001-79368 A JP 2008-238147 A US Pat. No. 5,851,355 US Pat. No. 6,156,680

  An object of the present invention is to provide a semipermeable membrane support that is excellent in smoothness of a semipermeable membrane application surface, does not allow the semipermeable membrane solution to penetrate, and has good adhesion to a non-application surface.

  In the present invention, the cross-sectional aspect ratio (fiber cross-section major axis / fiber cross-section minor axis) of the main synthetic fiber that has not been studied in the conventional semipermeable membrane support (hereinafter sometimes referred to as “cross-section aspect ratio”) This is a solution to the above problem.

  That is, the present invention is as follows.

(1) In the method for producing a semipermeable membrane support,
The semipermeable membrane support comprises at least two or more main synthetic fibers and binder synthetic fibers having different fiber diameters, and comprises a wet papermaking nonwoven fabric having a semipermeable membrane application surface and a semipermeable membrane non-application surface, The cross-sectional aspect ratio (fiber cross-section major axis / fiber cross-section minor axis) of the main synthetic fiber existing from the surface of the semipermeable membrane application surface to 1/3 in the thickness direction observed by the cross-sectional SEM and the semipermeable membrane non-application surface The cross-sectional aspect ratio (fiber cross-section major axis / fiber cross-section minor axis) of the main synthetic fiber existing from the surface to 1/3 is 1.2 to 3.0,
A single-layer wet paper manufactured by one type of paper machine selected from the group of long paper machines, circular paper machines, and inclined wire type paper machines, or a combination of the same or different types of paper machines selected from this group A wet paper with a multilayer structure manufactured by a combination paper machine is hot-pressure dried to produce a sheet, and then hot-pressed .
The surface temperature of the hot roll in hot pressure drying is 100 to 180 ° C., the pressure is 50 to 1000 N / cm,
The semipermeable membrane support, wherein the surface temperature of the hot roll in hot pressing is 150 to 260 ° C., the nip pressure of the roll is 190 to 1800 N / cm, and the processing speed is 3 to 100 m / min. Manufacturing method .
(2) The cross-sectional aspect ratio (fiber cross-section major axis / fiber cross-section minor axis) of the main synthetic fiber existing from the surface of the semipermeable membrane application surface to 1/3 is 1.3 to 3.0. A method for producing a semipermeable membrane support.
(3) The cross-sectional aspect ratio (fiber cross-section major axis / fiber cross-section minor axis) of the main synthetic fiber existing from the surface of the semipermeable membrane application surface to 1/3 is 1.4 to 3.0. A method for producing a semipermeable membrane support.
(4) Semi-transparent as described in (1), wherein the cross-sectional aspect ratio (fiber cross-section major axis / fiber cross-section minor axis) of the main synthetic fiber existing from the surface of the non-coated surface to 1/3 is 1.2 to 2.7 A method for producing a membrane support.
(5) Semi-transparent as described in (1), wherein the cross-sectional aspect ratio (fiber cross-section major axis / fiber cross-section minor axis) of the main synthetic fiber existing from the surface of the non-coated surface to 1/3 is 1.2 to 2.5 A method for producing a membrane support.
(6) The method for producing a semipermeable membrane support according to any one of (1) to (5), wherein the binder synthetic fiber is an unstretched synthetic fiber.
(7) The semipermeable membrane supporting material according to any one of (1) to (6), wherein the content of the binder synthetic fiber relative to the total mass of the main synthetic fiber and the binder synthetic fiber is more than 20% by mass and 40% by mass or less. Manufacturing method .
(8) The semipermeable membrane support according to any one of (1) to (6), wherein the content of the binder synthetic fiber relative to the total mass of the main synthetic fiber and the binder synthetic fiber is 25% by mass or more and 35% by mass or less. Manufacturing method .
(9) The average value of the longitudinal direction (MD) and transverse direction (CD) breaking lengths at 5% elongation of the nonwoven fabric is less than 4.0 km, and the transverse dimension (CD) heating dimensional change rate of the nonwoven fabric The method for producing a semipermeable membrane supporting material according to any one of (1) to (8), wherein is -0.3 to + 1.0%.
(10) Semipermeable membrane support according to (9), wherein the elongation percentage of the main synthetic fiber (JIS L1013 2010) is 25 to 150%, and the tensile strength of the main synthetic fiber is 0.08 to 0.8 N / tex. Body manufacturing method .
(11) The method for producing a semipermeable membrane supporting material according to any one of (1) to (10), wherein the nonwoven fabric has a multilayer structure .

The semipermeable membrane support of the present invention comprises a wet papermaking nonwoven fabric containing two or more main synthetic fibers and binder synthetic fibers having different fiber diameters. The main synthetic fiber according to the present invention has a substantially circular cross-sectional shape before the production of the nonwoven fabric, and is obtained by manufacturing wet paper using a paper machine, hot-pressure drying, and hot-pressure processing. in semipermeable membrane support of the present invention is a cross-sectional aspect ratio of the main synthetic fibers present to 1/3 from the surface of the semipermeable membrane coating surface及beauty uncoated surface observed in nonwoven sectional SEM 1.2 ~ 3.0. By having such a cross-sectional aspect ratio, the semipermeable membrane solution is difficult to be penetrated, the smoothness of the semipermeable membrane application surface is excellent, and a semipermeable membrane support with good adhesion of the non-application surface is produced. Became possible.

It is a fiber sectional view for explaining a fiber section major axis and a fiber section minor axis.

  The main synthetic fiber is a synthetic fiber that forms the skeleton of the semipermeable membrane support without melting and bonding at low temperature. For example, polyolefin, polyamide, polyacrylic, vinylon, vinylidene, polyvinyl chloride, polyester, benzoate, polyclar, and phenol fibers can be used, but the semipermeable membrane adhesion is improved. Polyester fibers that can be used and have high heat resistance are more preferable. Semi-synthetic fibers such as acetate, triacetate, promix, and regenerated fibers such as rayon, cupra, and lyocell fiber may be contained within a range that does not impair the performance.

  When the main synthetic fiber contains one type of fiber and the binder synthetic fiber contains two or more types of fibers with different fiber diameters, the binder synthetic fiber maintains its fiber shape during wet papermaking. Although it plays a role in forming complex fiber structures, the fiber shape changes due to softening or melting due to the drying process or hot pressing process, which ultimately contributes to the fiber network of the semipermeable membrane support. Hateful. As in the present invention, by containing two or more main synthetic fibers having different fiber diameters, a complex fiber structure is formed. On the semipermeable membrane application surface, smoothness is high, there are few irregularities, and half The effect that the adhesion between the permeable membrane and the semipermeable membrane support is excellent is obtained, and the effect that the adhesion between the non-coated surfaces is high is obtained on the non-coated surface. Moreover, since the semipermeable membrane solution permeates between the intricately entangled fibers, the back-through is also suppressed. The main synthetic fiber having a large fiber diameter is referred to as “thick fiber”, and the main synthetic fiber having a small fiber diameter is referred to as “thin fiber”.

  The cross-sectional shape of the main fiber is preferably substantially circular, and the cross-sectional aspect ratio of the main fiber before dispersion in water in the paper making process is preferably 1.0 to less than 1.2. If the cross-sectional aspect ratio of the main fiber before dispersion in water is 1.2 or more, the uniformity of the nonwoven fabric or the smoothness of the semipermeable membrane application surface may be caused by the fiber dispersibility being reduced or the occurrence of fiber entanglement or tangles. May adversely affect sex. About the fiber which has irregular cross sections, such as T type, Y type, and a triangle, it can contain in the range which does not inhibit other characteristics, such as fiber dispersibility, for back-through prevention and surface smoothness. 30 mass% or less is preferable with respect to a nonwoven fabric, as for the compounding quantity in the case of mix | blending the fiber which has an atypical cross section, 20 mass% or less is more preferable, and 10 mass% or less is further more preferable.

  The fiber diameter of the thick fiber is not particularly limited, but is preferably 30.0 μm or less, more preferably 2.0 to 25.0 μm, still more preferably 5.0 to 20.0 μm, and particularly preferably 10 0.0-20.0 μm. If it is less than 2.0 μm, the adhesion between the non-coated surfaces may deteriorate. When the fiber diameter of the main fiber exceeds 30.0 μm, the smoothness of the semipermeable membrane application surface is lowered, and the back-through of the semipermeable membrane solution may occur. In addition, fluff may be easily formed on the surface of the nonwoven fabric. Although the fiber length of a large diameter fiber is not specifically limited, Preferably it is 1-12 mm, More preferably, it is 3-10 mm, More preferably, it is 4-6 mm.

  The aspect ratio (fiber length / fiber diameter) of the large diameter fiber is preferably 200 to 1000, more preferably 220 to 900, and still more preferably 280 to 800. When the aspect ratio is less than 200, the dispersibility of the fiber is good. However, when the fiber is dropped from the paper making wire during paper making, or when the fiber is stuck in the paper making wire and the peelability from the wire is deteriorated. There is. On the other hand, when it exceeds 1000, although it contributes to the formation of a three-dimensional network of fibers, the occurrence of entanglement and entanglement may adversely affect the uniformity of the nonwoven fabric and the smoothness of the semipermeable membrane coated surface.

  10-70 mass% is preferable, as for content of the large diameter fiber with respect to the total mass of a main body synthetic fiber and a binder synthetic fiber, 20-60 mass% is more preferable, and 30-50 mass% is further more preferable. When the content of the large-diameter fiber is less than 10% by mass, the hardness of the nonwoven fabric may be insufficient. Moreover, when it exceeds 70 mass%, there exists a possibility of breaking by intensity | strength lack.

  The fine fiber is a fiber having a smaller fiber diameter than that of the thick fiber, and is preferably a fiber having an aspect ratio equal to or greater than that of the thick fiber. The aspect ratio (fiber length / fiber diameter) of the fine fiber is preferably 200 to 2000, more preferably 300 to 1500, and still more preferably 400 to 1000. When the aspect ratio is less than 200, the dispersibility of the fiber is good, but the fiber may fall off the paper making wire during paper making, or the fiber may be stuck in the paper making wire and the peelability from the wire may deteriorate. is there. On the other hand, if it exceeds 2000, fine fibers contribute to the formation of a three-dimensional network, but if the fibers are entangled or entangled, the uniformity of the nonwoven fabric and the smoothness of the semipermeable membrane coated surface are adversely affected. There is a case.

  The small-diameter fiber plays a role of filling a gap in the skeleton of the semipermeable membrane support formed by the large-diameter fiber to form a uniform and complicated three-dimensional network. Moreover, the effect | action which controls the space | gap, improves smoothness, and suppresses the fuzz on the semipermeable membrane support body surface is expressed. Therefore, the fiber diameter of the small-diameter fiber is not particularly limited as long as it is thinner than the large-diameter fiber. Preferably it is 2.0-20.0 micrometers, More preferably, it is 3.0-18.0 micrometers, More preferably, it is 5.0-15.0 micrometers. Moreover, in order to improve the smoothness of a semipermeable membrane application surface, it is important that the crimp is not added to the thin fiber. The fiber length of the fine fiber is not particularly limited, but is preferably 1 to 12 mm, more preferably 2 to 10 mm, further preferably 3 to 6 mm, and particularly preferably 4 to 6 mm.

  10-70 mass% is preferable, as for content of the small diameter fiber with respect to the total mass of a main body synthetic fiber and a binder synthetic fiber, 20-60 mass% is more preferable, and 30-50 mass% is further more preferable. When the content of the fine fiber is less than 10% by mass, the formation may be deteriorated. Moreover, when it exceeds 70 mass%, there exists a possibility that it may be torn by the fear that the hardness of a nonwoven fabric may run short or the intensity | strength is insufficient.

  A large diameter fiber and a small diameter fiber may be selected and used one by one, or a combination of a plurality of types of large diameter fibers and one type of small diameter fiber, one type of large diameter fiber and a plurality of types of small diameter fibers A combination of these can be selected as appropriate.

  The binder synthetic fiber is a fiber intended to melt and bond by incorporating a process of raising the temperature to the softening point or higher than the melting temperature (melting point) into the manufacturing process of the semipermeable membrane support, and the semipermeable membrane support. Improve the mechanical strength. For example, a semipermeable membrane support can be produced by a wet papermaking method, and the binder synthetic fiber can be softened or melted by a subsequent drying step or hot pressing.

  Examples of the binder synthetic fiber include composite fibers such as a core-sheath type (core-shell type), a parallel type (side-by-side type), and a radial split type, and unstretched fibers. More specifically, a combination of polypropylene (core) and polyethylene (sheath), a combination of polypropylene (core) and ethylene vinyl alcohol (sheath), a combination of high melting point polyester (core) and low melting point polyester (sheath), high melting point Examples include composite fibers such as a combination of polyester (core) and polyethylene (sheath), and unstretched fibers such as polyester. Since the composite fiber hardly forms a film, the mechanical strength can be improved while maintaining the space of the semipermeable membrane support. In addition, a single fiber (fully fused type) composed only of a low melting point resin such as polyethylene or polypropylene, or a hot water-soluble binder such as polyvinyl alcohol easily forms a film in the drying process of the semipermeable membrane support. However, it can be used as long as the properties are not impaired. In the present invention, a combination of a high-melting polyester (core) and a low-melting polyester (sheath), unstretched fibers such as polyester can exhibit strength when forming a nonwoven fabric by a wet papermaking method, In this case, it can be preferably used because the second-stage strength can be developed. Unstretched fibers such as polyester are particularly preferable because they have a binder component more than the core-sheath fiber, and thus it is easy to obtain adhesive strength.

  Although the fiber diameter of a binder synthetic fiber is not specifically limited, Preferably it is 2.0-20.0 micrometers, More preferably, it is 5.0-15.0 micrometers, More preferably, it is 7.0-12.0 micrometers. . Moreover, it is preferable that it is a fiber diameter different from a main synthetic fiber, and it is especially preferable that it is a fiber diameter thinner than a large diameter fiber. Because the fiber diameter is different from the main synthetic fiber, the binder synthetic fiber has the role of forming a uniform three-dimensional network with the main synthetic fiber during wet papermaking in addition to the role of improving the mechanical strength of the semipermeable membrane support. Fulfill. Furthermore, in the step of raising the temperature to the softening temperature or melting temperature of the binder synthetic fiber, the smoothness of the semipermeable membrane support surface can be improved, and in this step, it is more effective when accompanied by pressurization. is there.

  Although the fiber length of a binder synthetic fiber is not specifically limited, Preferably it is 1-12 mm, More preferably, it is 3-10 mm, More preferably, it is 3-6 mm, Most preferably, it is 4-6 mm. The cross-sectional shape of the binder synthetic fiber is preferably substantially circular. However, fibers having irregular cross-sections such as T-type, Y-type, and triangle can also be used to prevent back-through, smoothness of a semipermeable membrane application surface, and adhesion between non-application surfaces. Therefore, it can be contained within a range that does not inhibit other characteristics.

  The aspect ratio (fiber length / fiber diameter) of the binder synthetic fiber is preferably 200 to 1000, more preferably 300 to 800, and still more preferably 400 to 700. When the aspect ratio is less than 200, the dispersibility of the fibers is good, but the fibers may fall off from the paper making wire during paper making, or the fibers may pierce the paper making wire and the peelability from the wire may deteriorate. There is. On the other hand, if it exceeds 1000, the binder synthetic fiber contributes to the formation of a three-dimensional network, but if the fibers are entangled or entangled, the uniformity of the nonwoven fabric and the smoothness of the semipermeable membrane coated surface are adversely affected. Sometimes.

  The content of the binder synthetic fiber with respect to the total mass of the main synthetic fiber and the binder synthetic fiber is preferably more than 20% by mass and 40% by mass or less, more preferably more than 20% by mass and 35% by mass or less, and more preferably 25% by mass to 35% by mass. More preferred are: When the content of the binder synthetic fiber is 20% by mass or less, there is a fear that fuzzing increases or there is a risk of tearing due to insufficient strength. Moreover, when it exceeds 40 mass%, there exists a possibility that liquid permeability may fall or sticking to a roll may occur at the time of hot pressing.

  The semipermeable membrane support of the present invention may be a multilayer nonwoven fabric in which the fiber blending of each layer is the same, or may be a multilayer nonwoven fabric in which the fiber blending of each layer is different. By making the multilayer structure, the basis weight of each layer is lowered, so that the fiber concentration of the slurry can be lowered, so that the formation of the nonwoven fabric is improved. As a result, the smoothness and uniformity of the semipermeable membrane application surface is improved. improves. Moreover, even when the formation of each layer is non-uniform | heterogenous, it can compensate by laminating | stacking. Further, the paper making speed can be increased, and the operability is improved.

  The method for producing the semipermeable membrane support of the present invention will be described. The semipermeable membrane support of the present invention is formed into a sheet by a wet papermaking method and then hot-pressed with a hot roll.

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

  As the paper machine, for example, a long net paper machine, a circular net paper machine, or an inclined wire type paper machine can be used. These paper machines can be used alone, or a combination paper machine in which two or more same or different types of paper machines are installed online may be used. In addition, when the nonwoven fabric has a multilayer structure of two or more layers, a fiber bonding method in which wet papers made by each paper machine are laminated, or after forming one sheet, fibers are placed on the sheet. Any method of casting the dispersed slurry may be used.

  Sheets are obtained by drying wet paper produced by a paper machine with a Yankee dryer, air dryer, cylinder dryer, suction drum dryer, infrared dryer, or the like. When the wet paper is dried, it is brought into close contact with a hot roll such as a Yankee dryer and dried by heat and pressure to improve the smoothness of the contacted surface. Hot-pressure drying means that the wet paper is pressed against the heat roll with a touch roll or the like and dried. The surface temperature of the hot roll is preferably 100 to 180 ° C, more preferably 100 to 160 ° C, and still more preferably 110 to 160 ° C. The pressure is preferably 50 to 1000 N / cm, more preferably 100 to 800 N / cm.

  Next, although hot press processing by a hot roll is demonstrated, this invention is not specified to the following. The sheet manufactured by the wet papermaking method is passed through the hot pressing process while niping between the rolls of the sheet hot pressing apparatus. Examples of the combination of rolls include two metal rolls, a metal roll and a resin roll, and a metal roll and a cotton roll. Two rolls heat one or both. At that time, both of them may be processed with two heated metal rolls, or may be hot-pressed with a combination of a heated metal roll and a resin roll, a heated metal roll and a cotton roll, or the like. Further, in a combination of a heated metal roll and a resin roll, a heated metal roll and a cotton roll, two heated metal rolls, etc., the surface that first contacts the cotton roll or the resin roll is in contact with the heated metal roll. You may press-process.

  A desired semipermeable membrane support is obtained by controlling the surface temperature of the hot roll, the nip pressure between the rolls, and the processing speed of the sheet. The surface temperature of the hot roll is preferably 150 to 260 ° C, more preferably 180 to 240 ° C. The roll nip pressure is preferably 190 to 1800 N / cm, more preferably 390 to 1500 N / cm. A processing speed becomes like this. Preferably it is 3-100 m / min, More preferably, it is 4-100 m / min, More preferably, it is 10-80 m / min. It is also possible to perform the hot pressing with a hot roll two or more times. In that case, two or more sets of rolls arranged in series may be used, or one set of rolls may be used. You may process twice. If necessary, the front and back of the sheet may be reversed.

In the thickness direction is observed by cross-sectional SEM of the nonwoven fabric in a semipermeable membrane support of the present invention, the surface of the cross-sectional aspect Hi及beauty uncoated surface of the metallic synthetic fibers present to 1/3 from the surface of the semipermeable membrane coating surface To 1/3, the cross-sectional aspect ratio of the main synthetic fiber is 1.2 to 3.0. It is important that the main synthetic fiber has a substantially circular shape with an aspect ratio of the fiber cross section of 1.0 to less than 1.2 in order to maintain good dispersibility and formation of the fiber until the wet papermaking process. The binder synthetic fiber is melted and deformed by subsequent hot-pressure drying and hot-pressing with a hot roll, so that it can be bonded to the main synthetic fiber to increase the strength and the surface smoothness. At this time, it is important to change the cross-sectional shape of the main synthetic fiber. The cross-sectional aspect ratio of the main synthetic fiber from 1 to 3 in the thickness direction observed in the cross-sectional SEM of the nonwoven fabric in the hot pressing process is from 1.0 to less than 1.2 to 1.2. It is important to increase to ~ 3.0. In order to keep the cross-sectional aspect ratio in the range of 1.2 to 3.0, in the process of drying by wet pressure in the wet papermaking process, the process is performed in the process of hot-pressure drying in close contact with a heat roll such as a Yankee dryer. The pressure can be controlled by increasing the pressure with which the wet paper is pressed against the heat roll. Moreover, the surface temperature of the hot roll at the time of hot pressing, the nip pressure between rolls, and the processing speed are controlled. When the hot roll temperature is high, the nip pressure is high, and the processing speed is low, the aspect ratio becomes large. However, when they are synergistically excessive, liquid permeability and air permeability may be impaired.

  The cross-sectional aspect ratio of the fiber is measured by cutting the semipermeable membrane support in a direction crossing the flow direction of the semipermeable membrane support, taking an SEM (electron microscope) photograph of the cross section, The thickness is divided into three equal parts, and is cut perpendicularly to the fiber length direction among the fibers existing up to 1/3 of the total thickness from the front surface to the back surface of the semipermeable membrane application surface. Ten large-diameter fibers and 10 small-diameter fibers are randomly found, the fiber cross-section major axis and the fiber cross-section minor axis are measured, the cross-section aspect ratio is calculated, and the average value is taken as the cross-section aspect ratio of the main synthetic fiber. 1 (A) and 1 (B) are cross-sectional views of the fiber. After making the longest diameter among the fiber diameters into the fiber cross-section long axis, the longest of the fiber diameters orthogonal to the fiber cross-section is referred to as the fiber cross-section short axis. To do.

  When the cross-sectional aspect ratio of the main synthetic fiber existing from the surface of the semipermeable membrane application surface to 1/3 is less than 1.2, there is a problem that the membrane component is excessively permeated when the semipermeable membrane component is applied. There is a case. When the ratio exceeds 3.0, the membrane component does not enter the semipermeable membrane support, and the adhesion due to the anchor effect of the semipermeable membrane and the semipermeable membrane support is not satisfied, which may cause a problem of adhesion failure. . The cross-sectional aspect ratio of the main synthetic fiber existing from the surface of the semipermeable membrane application surface to 1/3 is more preferably 1.3 to 3.0, and further preferably 1.4 to 3.0. preferable.

  When the cross-sectional aspect ratio of the main synthetic fiber existing from the surface of the non-coated surface to 1/3 is less than 1.2, when the non-coated surfaces are bonded to each other, the adhesive permeates too much and there is a problem of poor adhesion. May occur. When 3.0 is exceeded, the adhesive agent does not enter, adhesion due to the anchor effect cannot be expected, and a problem of poor adhesion may occur. The cross-sectional aspect ratio of the main synthetic fiber existing 1/3 from the surface of the non-coated surface is more preferably 1.2 to 2.7, and further preferably 1.2 to 2.5.

  In the present invention, the cross-sectional aspect ratio of the main synthetic fiber existing up to 1/3 from the surface of the semipermeable membrane application surface and / or the cross-sectional aspect ratio of the main synthetic fiber existing up to 1/3 from the surface of the non-application surface Although it is specified, it is most preferable that the cross-sectional aspect ratio is within the range specified by the present invention in both the semipermeable membrane coated surface and the non-coated surface, and only the sectional aspect ratio of the semipermeable membrane coated surface Is preferably within the range defined by the present invention, and only the non-coated surface is preferably within the range defined by the present invention.

  Further, the cross-sectional aspect ratio of the main synthetic fiber present in the intermediate portion is not particularly limited. The cross-sectional aspect ratio of the main synthetic fiber existing in the intermediate portion is 1/3 from the cross-sectional aspect ratio of the main synthetic fiber existing from the surface of the semipermeable membrane application surface to 1/3 from the surface of the non-application surface. Although the cross-sectional aspect ratio of the main synthetic fiber is reflected, it is smaller than the cross-sectional aspect ratio of the main synthetic fiber existing near the surface. This is considered to be because the heat conduction is less in the hot pressing process than in the vicinity of the semipermeable membrane coated surface or the non-coated surface. In addition, the binder synthetic fiber distributed throughout the semipermeable membrane support is present between the main synthetic fibers in a form in which the fiber shape has been lost by hot pressing.

  In the present invention, the average value of the longitudinal direction (MD) and transverse direction (CD) breaking length at 5% elongation of the nonwoven fabric is less than 4.0 km, and the transverse dimension (CD) heating dimensional change The rate is preferably -0.3 to + 1.0%. In the semipermeable membrane coating process, the breaking length at 5% elongation of the semipermeable membrane support and the heating dimensional change rate are extremely important requirements. And especially the average value of the longitudinal direction (MD) and transverse direction (CD) breaking length at the time of 5% elongation of the nonwoven fabric constituting the semipermeable membrane support [hereinafter referred to as "average breaking length (at 5% elongation)" ”Is less than 4.0 km, and the transverse dimensional change rate (CD) before and after immersing the semipermeable membrane support in a 90 ° C. hot water bath for 10 minutes is −0.3 to + 1.0%. I learned that this is important.

  In the semipermeable membrane support of the present invention, the average breaking length (at 5% elongation) is preferably less than 4.0 km. If the average breaking length (at 5% elongation) of the semipermeable membrane support is 4.0 km or more, the strength becomes excessive and the air permeability may be lowered. In the semipermeable membrane support of the present invention, the average breaking length (at 5% elongation) is preferably less than 4.0 km, more preferably 3.8 km or less, and further preferably 3.6 km or less. Moreover, it is preferable that the transverse dimension (CD) heating dimensional change rate of the semipermeable membrane support is −0.3 to + 1.0%, more preferably −0.2 to + 0.8%, Preferably, it is -0.1 to + 0.6%. When the dimensional change rate in the transverse direction (CD) of the support is less than −0.3%, the shrinkage in the lateral direction is excessive, and wrinkles due to curling occur at the semipermeable membrane non-coated portion at the edge of the semipermeable membrane support. May occur. On the other hand, if it exceeds + 1.0%, wrinkles due to curling may occur in the entire width direction toward the semipermeable membrane application surface.

  In order to make the average breaking length (at 5% elongation) less than 4.0 km, the elongation percentage of the main synthetic fiber (JIS L1013 2010) is preferably 25 to 150%, and the tensile strength of the main synthetic fiber It is preferable that (JIS L1013 2010) is 0.08 to 0.80 N / tex. When the elongation percentage of the main synthetic fiber is less than 25%, the average tear length (at 5% elongation) may exceed 4.0 km, or the paper may be cut due to insufficient elongation of the nonwoven fabric during hot pressing. . On the other hand, if it exceeds 150%, wrinkles may occur due to excessive shrinkage of the nonwoven fabric during hot pressing. Therefore, the elongation percentage of the main synthetic fiber is preferably 25 to 150%, more preferably 30 to 120%, and still more preferably 35 to 100%. The tensile strength of the main synthetic fiber is preferably 0.08 to 0.80 N / tex, more preferably 0.10 to 0.70 N / tex, and still more preferably 0.20 to 0.60 N / tex. is there. In the case of less than 0.08 N / tex, paper breakage may be caused in the wet papermaking process for forming the nonwoven fabric or in the hot pressing process due to insufficient strength. Moreover, when it exceeds 0.80 N / tex, since the obtained nonwoven fabric is hard, not only smoothness may not be obtained even after hot pressing, but the breaking length is likely to exceed 4.0 km.

  In order to keep the dimensional change rate in the transverse direction (CD) of the semipermeable membrane support to −0.3 to + 1.0%, a hot roll such as a Yankee dryer is used when wet paper is dried in the wet papermaking process. It is important to optimally combine, for example, the roll temperature during hot pressing, the number of times of hot pressing, the heat processing after hot pressing, and the like within the above-mentioned range.

  The breaking length refers to a value measured in accordance with JIS P8113 1976, and is an index indicating the tensile strength of the nonwoven fabric itself that is not affected by the basis weight or width of the nonwoven fabric sample. And the "average tear length (at the time of 5% expansion | extension)" of the nonwoven fabric concerning the semipermeable membrane support body of this invention is calculated | required by the method explained in full detail in an Example.

  The rate of change in heating dimension is the semipermeable membrane support by heat applied to the semipermeable membrane support in the step of forming the semipermeable membrane on the semipermeable membrane support (for example, heat applied in the hot water washing step or drying step). The dimensional change of the body is quantified. It is important for this numerical value to fall within a specific range to suppress wrinkling and curving.

Although the basic weight of a semipermeable membrane support body is not specifically limited, 20-150 g / m < ² > is preferable, More preferably, it is 50-100 g / m < ² >. If it is less than 20 g / m ² , sufficient tensile strength may not be obtained. Moreover, when it exceeds 150 g / m < ² >, a liquid flow resistance may become high, thickness may increase, and a predetermined amount of semipermeable membrane may not be accommodated in a unit or a module.

The density of the semi-permeable membrane support is preferably 0.5 to 1.0 g / cm ^3, more preferably 0.6~0.9g / cm ^3. When the density of the semipermeable membrane support is less than 0.5 g / cm ³ , the thickness increases, and the area of the semipermeable membrane that can be incorporated into the unit is reduced. As a result, the life of the semipermeable membrane is shortened. May end up. On the other hand, when it exceeds 1.0 g / cm ³ , the liquid permeability may be lowered, and the life of the semipermeable membrane may be shortened.

  The thickness of the semipermeable membrane support is preferably 50 to 150 μm, more preferably 60 to 130 μm, and even more preferably 70 to 120 μm. When the thickness of the semipermeable membrane support exceeds 150 μm, the area of the semipermeable membrane that can be incorporated into the unit is reduced, and as a result, the life of the semipermeable membrane may be shortened. On the other hand, when the thickness is less than 50 μm, sufficient tensile strength may not be obtained or liquid permeability may be reduced, and the life of the semipermeable membrane may be shortened.

The invention is explained in more detail by means of examples. Hereinafter, unless otherwise specified, the parts and ratios described in the examples are based on mass. Examples 41, 42 and 56 are reference examples.

<Elongation rate and tensile strength of main synthetic fiber>
The elongation and tensile strength of the main synthetic fiber were measured by methods A and B.

Measurement A (Elongation rate of main synthetic fiber)
In accordance with JIS L1013 2010, the elongation of the main synthetic fiber was measured.

Measurement B (Tensile strength of the main synthetic fiber)
The tensile strength of the main synthetic fiber was measured in accordance with JIS L1013 2010.

<Evaluation>
The semipermeable membrane supports obtained in Examples and Comparative Examples were evaluated by the following tests.

Test 1 (thickness)
The thickness was measured according to JIS P8118.

Test 2 (Smoothness)
According to JIS P8119, it measured using the Beck smoothness tester.

Test 3 (X surface fiber fluffing)
A crease was made with the X surface as a mountain so as to cross the flow direction of the 30 cm-width semipermeable membrane support, and a cylindrical roll made of stainless steel with a diameter of 5 cm and a length of 40 cm was rolled on the crease. The number of fluffs of the fiber was measured. The measurement is performed at n = 4 and the average value is shown.

0 to 10: Very good level with less fuzz.
11 to 20: good level.
21-30: practically lower limit level.
31 or more: Unusable level.

Test 4 (Y surface fiber fluff)
A crease was made with the Y surface as a mountain so as to cross the flow direction of the semipermeable membrane support having a width of 30 cm, and a cylindrical roll made of stainless steel having a diameter of 5 cm and a length of 40 cm was rolled on the crease. The number of fluffs of the fiber was measured. The measurement is performed at n = 4 and the average value is shown.

0 to 10: Very good level with less fuzz.
11 to 20: good level.
21-30: practically lower limit level.
31 or more: Unusable level.

Test 5 (average fracture length at 5% elongation)
A test piece of length × width = 15 mm × 250 mm was taken from the semipermeable membrane support, and the test piece was used in accordance with JIS P8113 1976 with the distance between the two grippers set to 180 mm, The tensile strength in the transverse direction was measured, and the corresponding load at the time of 5% elongation was read to determine the breaking length. Next, the average value of the longitudinal and lateral tear lengths {(longitudinal 5% tear length + 5% transverse length) / 2} was determined, and the average tear length of the nonwoven fabric (5%). (Unit: km). When the width of the semipermeable membrane support exceeds 1000 mm, the semipermeable membrane support is sampled from three locations (right, center, left) in the lateral direction, and the longitudinal and lateral tears are taken. The length was measured, and the vertical and horizontal average values at all three locations were defined as the average breaking length (at 5% elongation). When the width of the semipermeable membrane support is 500 to 1000 mm, it is divided into two in the horizontal direction, sampled from two locations (right center, left center), and the longitudinal and lateral tear lengths are measured. The vertical and horizontal average values of all these two locations were taken as the average breaking length (at 5% elongation). When the width of the semipermeable membrane support was 500 mm or less, the average value in the vertical and horizontal directions at the center was used.

Test 6 (heating dimensional change rate)
The semipermeable membrane support is cut into a rectangle of 200 mm in the vertical direction and 1000 mm in the horizontal direction, marked at three locations in the horizontal direction, and the width is measured in units of 0.1 mm. After the dimension measurement, the semipermeable membrane support is immersed in a 90 ° C. hot water bath for 10 minutes, and then the moisture is wiped off. Again, the same three widths are measured in units of 0.1 mm. The amount of dimensional change before and after being immersed in a 90 ° C. hot water bath was calculated, and the heating dimensional change rate relative to the size before being immersed in the hot water bath was determined.

Test 7 (Situation during hot pressing)
The occurrence of paper breaks and wrinkles at the heating roll outlet was confirmed in the hot-pressure processing of the nonwoven fabric. When there was no paper break or wrinkle, “○” was given.

Test 8 (semi-permeable membrane soaking)
Using a constant speed coating apparatus (trade name: Automatic Film Applicator, manufactured by Yasuda Seiki Co., Ltd.) having a certain clearance, a polysulfone resin (manufactured by SIGMA-ALDRICH Corporation, weight) is used on the X or Y surface of the semipermeable membrane support. A dimethylformamide (DMF) solution (concentration: 18% by mass) having an average molecular weight M _w <35,000 and a number average molecular weight M _n <16,000, product number 428302) is applied, washed with water, dried, A polysulfone membrane was formed on the surface to prepare a semipermeable membrane, and a cross-sectional SEM photograph of the semipermeable membrane was taken to evaluate the degree of penetration of the polysulfone resin into the semipermeable membrane support.

(Double-circle): The polysulfone resin has soaked only to the vicinity of the center of the semipermeable membrane support. Very good level.
○: The polysulfone resin does not ooze out on the non-coated surface of the semipermeable membrane support. Good level.
Δ: The polysulfone resin oozes partly on the non-coated surface of the semipermeable membrane support. Practically usable level.
X: The polysulfone resin oozes out on the non-application surface of the semipermeable membrane support. Unusable level for practical use.

Test 9 (Semipermeable membrane adhesion)
Regarding the semipermeable membrane produced in Test 8, the degree of adhesion between the semipermeable membrane made of polysulfone resin and the semipermeable membrane support was determined by the degree of resistance when peeling.

(Double-circle): The adhesiveness of a semipermeable membrane and a semipermeable membrane support body is very high, and cannot peel. Very good level.
○: There is a place where it is easy to partially peel off. Good level.
Δ: The semipermeable membrane and the semipermeable membrane support are adhered, but are easy to peel off as a whole. Practically lower limit level.
X: Peeling occurs in the water washing or drying step after the semipermeable membrane application. Unusable level.

Test 10 (non-coated surface adhesion)
Between the non-application surfaces of the semipermeable membrane support on which the semipermeable membrane was prepared in Test 8, a heated and melted vinyl acetate adhesive was applied and immediately pressed to adhere. After bonding, the sample was cut into a width of 25 mm and a length of 200 mm, and a tensile tester (trade name: STA-1150 Tensilon tensile tester, manufactured by Orientec Co., Ltd.) was used, with a peeling angle of 180 degrees and a peeling speed of 100 mm / min. A peel test of the bonded portion was performed to evaluate non-coated surface adhesion.

(Double-circle): Peeling strength is very high and peeling has occurred inside the semipermeable membrane support layer.
○: Peeling strength is high, and partial peeling occurs between the adhesive and the semipermeable membrane support, but most peeling occurs within the semipermeable membrane support layer.
(Triangle | delta): Although peeling strength is somewhat high and peeling has occurred between an adhesive agent and a semipermeable membrane support body, peeling is also confirmed inside a semipermeable membrane support body layer. Practically lower limit level.
X: Peeling strength is low, and peeling occurs between the adhesive and the semipermeable membrane support as a whole. Unusable level.

Test 11 (wrinkles when semipermeable membrane is applied)
In a semipermeable membrane coating step on a semipermeable membrane support, a DMF solution of polysulfone (manufactured by SIGMA-ALDRICH Corporation, weight average molecular weight M _w <35,000, number average molecular weight M _n <16,000, product number 428302) ( After coating the X surface or Y surface with a concentration of 18% by mass and a temperature of 20 ° C., the polysulfone was solidified by immersing in 20 ° C. pure water, and then the occurrence of wrinkles after washing in a 85 ° C. hot water bath was confirmed. .

○: No wrinkle or slight wrinkle but good level.
Δ: Some wrinkles are observed, but the practical lower limit level.
X: Many wrinkles are generated and it is not practical.

(Example 1)
Large diameter fiber (stretched polyester fiber, fiber diameter 14.3 μm, fiber length 5 mm, elongation 45%, tensile strength 0.40 N / tex), binder synthetic fiber (unstretched polyester fiber, fiber diameter 10.5 μm, Fiber length 5mm, melting point 230 ° C), fine fiber (stretched polyester fiber, fiber diameter 6.4μm, fiber length 5mm, elongation 45%, tensile strength 0.40N / tex) 35:30:35 After mixing and dispersing in water at a ratio and forming wet paper with a circular paper machine, it was hot-pressure dried with a Yankee dryer having a surface temperature of 130 ° C. to obtain a sheet having a basis weight of 80 g / m ² .

  The obtained sheet was hot-pressed under the conditions of a temperature of 200 ° C., a pressure of 785 N / cm, and a processing speed of 6 m / min, using a calender device that is a combination of a heated metal roll and a heated metal roll, and a semipermeable membrane support was obtained. Obtained. In addition, the surface which contacted the Yankee dryer was made into the X surface.

(Example 2)
A semipermeable membrane support was obtained in the same manner as in Example 1 except that the processing speed at the time of hot pressing was 30 m / min.

(Example 3)
A semipermeable membrane support was obtained in the same manner as in Example 1 except that the processing speed during hot pressing was 60 m / min.

Example 4
A semipermeable membrane support was obtained in the same manner as in Example 1 except that the processing speed during hot pressing was 4 m / min.

(Example 5)
A semipermeable membrane support was obtained in the same manner as in Example 1 except that the processing speed during hot pressing was 9 m / min.

(Example 6)
A semipermeable membrane support was obtained in the same manner as in Example 1 except that the processing speed during hot pressing was 3 m / min.

(Example 7)
A semipermeable membrane support was obtained in the same manner as in Example 1 except that the processing speed at the time of hot pressing was set to 5.5 m / min.

(Example 8)
A semipermeable membrane support was obtained in the same manner as in Example 1 except that the processing speed at the time of hot pressing was 5 m / min.

(Comparative Example 1)
A semipermeable membrane support was obtained in the same manner as in Example 1 except that the processing speed during hot pressing was 2 m / min.

(Comparative Example 2)
A semipermeable membrane support was obtained in the same manner as in Example 1 except that the processing speed at the time of hot pressing was 120 m / min.

The semipermeable membrane supports of Examples 1 to 8 contain at least two or more types of main synthetic fibers and binder synthetic fibers having different fiber diameters, and are present from the surface of the semipermeable membrane application surface to 1/3. sectional aspect ratio of the main synthetic fibers present to 1/3 from a cross-sectional aspect Hi及beauty uncoated surface surface of the synthetic fibers is 1.2 to 3.0, conditions at the time hot press, bleeding semipermeable membrane In the evaluation of wrinkles, semi-permeable membrane adhesiveness, surface fluffing, and wrinkles during semi-permeable membrane application, a practically usable level was achieved.

  From the comparison of the penetration of the semipermeable membrane in Examples 1 to 8, it was confirmed that the case where the cross-sectional aspect ratio of the semipermeable membrane application surface was 1.3 or more was superior.

  From the comparison of Examples 1 to 8, there is less fuzz when the cross-sectional aspect ratio is 1.3 to 3.0, and less fuzz when the cross-sectional aspect ratio is 1.4 to 3.0. confirmed.

  From the evaluation results of the non-coated surface adhesiveness in Examples 1 to 8, it was confirmed that the cross-sectional aspect ratio of the non-coated surface is close to 1.2, the adhesiveness is high. Further, it is understood that the cross-sectional aspect ratio is more preferably 2.7 or less, and further preferably 2.5 or less.

  Although the semipermeable membrane support of Comparative Example 1 contains at least two or more main synthetic fibers and binder synthetic fibers having different fiber diameters, the cross-sectional aspect ratio of the main synthetic fibers exceeds 3.0. Therefore, the semipermeable membrane adhesion and the non-coated surface adhesion were poor. Further, the semipermeable membrane support of Comparative Example 2 has a surface aspect ratio of less than 1.2 of the main synthetic fiber, so that the surface is very fluffy, the evaluation result of the semipermeable membrane soaking is poor, and is practical. It was not suitable.

Example 9
Large diameter fiber (stretched polyester fiber, fiber diameter 24.7 μm, fiber length 5 mm, elongation 45%, tensile strength 0.40 N / tex), binder synthetic fiber (unstretched polyester fiber, fiber diameter 10.5 μm, Fiber length 5mm, melting point 230 ° C), fine fiber (stretched polyester fiber, fiber diameter 14.3μm, fiber length 5mm, elongation 45%, tensile strength 0.40N / tex) 35:30:35 After mixing and dispersing in water at a ratio and forming wet paper with a circular paper machine, it was hot-pressure dried with a Yankee dryer having a surface temperature of 130 ° C. to obtain a sheet having a basis weight of 80 g / m ² .

  The obtained sheet was hot-pressed under the conditions of a temperature of 200 ° C., a pressure of 785 N / cm, and a processing speed of 30 m / min using a calendering device that is a combination of a heated metal roll and a heated metal roll, and a semipermeable membrane support was obtained. Obtained. In addition, the surface which contacted the Yankee dryer was made into the X surface.

(Example 10)
Large diameter fiber (stretched polyester fiber, fiber diameter 24.7 μm, fiber length 5 mm, elongation 45%, tensile strength 0.40 N / tex), binder synthetic fiber (unstretched polyester fiber, fiber diameter 10.5 μm, Fiber length 5 mm, melting point 230 ° C.), fine fiber (stretched polyester fiber, fiber diameter 17.5 μm, fiber length 5 mm, elongation 45%, tensile strength 0.40 N / tex) 35:30:35 After mixing and dispersing in water at a ratio and forming wet paper with a circular paper machine, it was hot-pressure dried with a Yankee dryer having a surface temperature of 130 ° C. to obtain a sheet having a basis weight of 80 g / m ² .

  The obtained sheet was hot-pressed under the conditions of a temperature of 200 ° C., a pressure of 785 N / cm, and a processing speed of 30 m / min using a calendering device that is a combination of a heated metal roll and a heated metal roll, and a semipermeable membrane support was obtained. Obtained. In addition, the surface which contacted the Yankee dryer was made into the X surface.

(Example 11)
The same method as in Example 9, except that unstretched polyester fiber (fiber diameter 10.5 μm, fiber length 5 mm, melting point 260 ° C.) was used as the binder synthetic fiber, and the temperature during hot pressing was 225 ° C. Thus, a semipermeable membrane support was obtained.

(Example 12)
The same method as in Example 10 except that unstretched polyester fiber (fiber diameter 10.5 μm, fiber length 5 mm, melting point 260 ° C.) was used as the binder synthetic fiber, and the temperature during hot pressing was 225 ° C. Thus, a semipermeable membrane support was obtained.

(Example 13)
Example 9 except that a core-sheath polyester fiber (fiber diameter: 10.5 μm, fiber length: 5 mm, sheath melting point: 107 ° C.) was used as the binder synthetic fiber, and the temperature during hot pressing was 160 ° C. A semipermeable membrane support was obtained in the same manner.

(Example 14)
Example 10 except that a core-sheath type polyester fiber (fiber diameter: 10.5 μm, fiber length: 5 mm, sheath melting point: 107 ° C.) was used as the binder synthetic fiber, and the temperature during hot pressing was 160 ° C. A semipermeable membrane support was obtained in the same manner as above.

The semipermeable membrane supports of Examples 9 to 14 contain at least two or more types of main synthetic fibers and binder synthetic fibers having different fiber diameters, and are present from the surface of the semipermeable membrane application surface to 1/3. sectional aspect ratio of the main synthetic fibers present to 1/3 from a cross-sectional aspect Hi及beauty uncoated surface surface of the synthetic fibers is 1.2 to 3.0, impregnation semipermeable membrane, a semipermeable membrane adhesion In the evaluation of non-coated surface adhesiveness and wrinkles during semipermeable membrane coating, a practically usable level was achieved.

  The semipermeable membrane support of Example 11 and Example 12 using unstretched polyester fibers having a melting point of 260 ° C. as binder synthetic fibers was carried out using unstretched polyester fibers having a melting point of 230 ° C. as binder synthetic fibers. Compared to the semipermeable membrane supports of Examples 9 and 10, there was a tendency for the cross-sectional aspect ratio of the main synthetic fibers to increase, and fuzzing decreased.

  Semi-permeable membranes of Examples 9-12 using unstretched polyester fibers as binder synthetic fibers compared to the semi-permeable membrane supports of Examples 13 and 14 using core-sheath type polyester fibers as binder synthetic fibers The support had a tendency to increase the cross-sectional aspect ratio and had less fuzz. Moreover, in Example 13 and 14, the wrinkle by sticking to a hot roll generate | occur | produced in the case of the hot-pressure process.

(Example 15)
Large diameter fiber 1 (stretched polyester fiber, fiber diameter 17.5 μm, fiber length 5 mm, elongation 40%, tensile strength 0.50 N / tex), large diameter fiber 2 (stretched polyester fiber, fiber diameter 12.5 μm) , Fiber length 5 mm, elongation 40%, tensile strength 0.50 N / tex), binder synthetic fiber (unstretched polyester fiber, fiber diameter 10.5 μm, fiber length 5 mm, melting point 230 ° C.), fine fiber (stretched) Polyester fiber, fiber diameter 7.4 μm, fiber length 5 mm, elongation 40%, tensile strength 0.5 N / tex) is mixed and dispersed in water at a blending ratio of 30: 30: 30: 10. After forming the wet paper, a sheet having a basis weight of 80 g / m ² was obtained by hot-pressure drying with a Yankee dryer having a surface temperature of 130 ° C.

  Sheet winding is installed in an unwinding device, and after 60 minutes from hot-pressure drying with a Yankee dryer, the sheet is calendered with a combination of a heated metal roll (200 ° C.) and a heated metal roll (200 ° C.) (first A calender device (second hot pressure roll nip, roll nip pressure 736 N / cm) of a combination of a hot pressure roll nip, roll nip pressure 490 N / cm), a heated metal roll (200 ° C.) and an elastic roll (normal temperature) is arranged in series. Using a device, hot pressing is performed under the conditions of a hot pressing speed of 30 m / min (the fiber substrate passes through the second hot pressing roll nip 12 seconds after passing through the first hot pressing roll nip), and is supported by a semipermeable membrane. Got the body. The surface in contact with the heated metal roll surface of the second hot-press roll nip was defined as the X surface.

(Example 16)
A semipermeable membrane support was obtained in the same manner as in Example 15 except that the roll nip pressure of the first hot pressure roll nip was changed to 736 N / cm.

(Example 17)
A semipermeable membrane support was obtained in the same manner as in Example 15 except that the roll nip pressure of the first hot pressure roll nip was set to 981 N / cm.

(Example 18)
A semipermeable membrane support was obtained in the same manner as in Example 15 except that the roll nip pressure of the first hot pressure roll nip was changed to 1226 N / cm.

(Example 19)
A semipermeable membrane support was obtained in the same manner as in Example 15 except that the roll nip pressure of the first hot pressure roll nip was changed to 1471 N / cm.

(Example 20)
A semipermeable membrane support was obtained in the same manner as in Example 15 except that the roll nip pressure of the first hot pressure roll nip was changed to 1717 N / cm.

(Example 21)
As the binder synthetic fiber, unstretched polyester fiber (fiber diameter 10.5 μm, fiber length 5 mm, melting point 260 ° C.) is used, and the first hot press roll nip has a roll nip pressure of 736 N / cm, and the first hot press roll nip A semipermeable membrane support was obtained in the same manner as in Example 15 except that the temperature of the two heated metal rolls was set to 225 ° C.

(Comparative Example 3)
A semipermeable membrane support was obtained in the same manner as in Example 15 except that the roll nip pressure of the first and second hot pressure roll nips was 245 N / cm.

(Comparative Example 4)
A semipermeable membrane support was obtained in the same manner as in Example 15 except that the roll nip pressure of the first hot-pressure roll nip was 1961 N / cm.

The semipermeable membrane supports of Examples 15 to 21 contain at least two or more types of main synthetic fibers and binder synthetic fibers having different fiber diameters, and are present from the surface of the semipermeable membrane application surface to 1/3. sectional aspect ratio of the main synthetic fibers present to 1/3 from a cross-sectional aspect Hi及beauty uncoated surface surface of the synthetic fibers is 1.2 to 3.0, impregnation semipermeable membrane, a semipermeable membrane adhesion In the evaluation of non-coated surface adhesiveness, wrinkles during semipermeable membrane coating, and surface fluffing, a practically usable level was achieved.

  From a comparison between Example 16 and Example 21, the semipermeable membrane support of Example 21 using unstretched polyester fiber having a melting point of 260 ° C. as the binder synthetic fiber was obtained by using unstretched polyester fiber having a melting point of 230 ° C. Compared with the semipermeable membrane support of Example 16 used as a binder synthetic fiber, there was less fuzzing, and the semipermeable membrane soaking and non-coated surface adhesion were good when the X surface was a semipermeable membrane coated surface. However, the semipermeable membrane adhesiveness and the non-coated surface adhesiveness were slightly inferior when the Y surface was a semipermeable membrane coated surface.

  The semipermeable membrane support of Comparative Example 3 contains at least two or more kinds of main synthetic fibers and binder synthetic fibers having different fiber diameters, but exists from the surface of the semipermeable membrane application surface to 1/3. Since the cross-sectional aspect ratio of the main synthetic fiber and the cross-section aspect ratio of the main synthetic fiber existing 1/3 from the surface of the non-coated surface are less than 1.2, the fluffing of the X and Y planes is very large, The permeation of the permeable membrane was poor, and it was not suitable for practical use. On the other hand, the semipermeable membrane support of Comparative Example 4 contains at least two or more main synthetic fibers and binder synthetic fibers having different fiber diameters, but from the surface of the semipermeable membrane application surface to 1/3. Since the cross-sectional aspect ratio of the main synthetic fiber existing in the cross section and the cross-sectional aspect ratio of the main synthetic fiber existing 1/3 from the surface of the non-coated surface exceeds 3.0, the non-coated surface adhesion is poor, and X The semipermeable membrane adhesion when the surface was coated with a semipermeable membrane was also poor.

(Example 22)
Large diameter fiber (stretched polyester fiber, fiber diameter 14.3 μm, fiber length 5 mm, elongation 40%, tensile strength 0.50 N / tex), binder synthetic fiber (unstretched polyester fiber, fiber diameter 10.5 μm, The blending ratio of fiber length 5 mm, melting point 230 ° C.) and fine fiber (stretched polyester fiber, fiber diameter 6.4 μm, fiber length 5 mm, elongation 40%, tensile strength 0.50 N / tex) is 41:18: A semipermeable membrane support was obtained in the same manner as in Example 2 except that the amount was 41.

(Example 23)
Large diameter fiber (stretched polyester fiber, fiber diameter 14.3 μm, fiber length 5 mm, elongation 40%, tensile strength 0.50 N / tex), binder synthetic fiber (unstretched polyester fiber, fiber diameter 10.5 μm, The blending ratio of fiber length 5 mm, melting point 230 ° C., fine fiber (stretched polyester fiber, fiber diameter 6.4 μm, fiber length 5 mm, elongation 40%, tensile strength 0.50 N / tex) is 40:20: A semipermeable membrane support was obtained in the same manner as in Example 2 except that the number was 40.

(Example 24)
Large diameter fiber (stretched polyester fiber, fiber diameter 14.3 μm, fiber length 5 mm, elongation 40%, tensile strength 0.50 N / tex), binder synthetic fiber (unstretched polyester fiber, fiber diameter 10.5 μm, The blending ratio of fiber length 5 mm, melting point 230 ° C., fine fiber (stretched polyester fiber, fiber diameter 6.4 μm, fiber length 5 mm, elongation 40%, tensile strength 0.50 N / tex) is 40:21: A semipermeable membrane support was obtained in the same manner as in Example 2, except that the number was 39.

(Example 25)
Large diameter fiber (stretched polyester fiber, fiber diameter 14.3 μm, fiber length 5 mm, elongation 40%, tensile strength 0.50 N / tex), binder synthetic fiber (unstretched polyester fiber, fiber diameter 10.5 μm, The blending ratio of fiber length 5 mm, melting point 230 ° C.) and fine fiber (stretched polyester fiber, fiber diameter 6.4 μm, fiber length 5 mm, elongation 40%, tensile strength 0.50 N / tex) is 38:25: A semipermeable membrane support was obtained in the same manner as in Example 2 except that it was 37.

(Example 26)
Large diameter fiber (stretched polyester fiber, fiber diameter 14.3 μm, fiber length 5 mm, elongation 40%, tensile strength 0.50 N / tex), binder synthetic fiber (unstretched polyester fiber, fiber diameter 10.5 μm, The blending ratio of the fiber length 5 mm, melting point 230 ° C.) and fine fiber (stretched polyester fiber, fiber diameter 6.4 μm, fiber length 5 mm, elongation 40%, tensile strength 0.50 N / tex) is 35:35: A semipermeable membrane support was obtained in the same manner as in Example 2 except that the number was 30.
(Example 27)
Large fiber (stretched polyester fiber, fiber diameter 14.3 μm, fiber length 5 mm, elongation 40%, tensile strength 0.5 N / tex), binder synthetic fiber (unstretched polyester fiber, fiber diameter 10.5 μm, The blending ratio of fiber length 5 mm, melting point 230 ° C., fine fiber (stretched polyester fiber, fiber diameter 6.4 μm, fiber length 5 mm, elongation 40%, tensile strength 0.5 N / tex) is 33:37: A semipermeable membrane support was obtained in the same manner as in Example 2 except that the number was 30.

(Example 28)
Large fiber (stretched polyester fiber, fiber diameter 14.3 μm, fiber length 5 mm, elongation 40%, tensile strength 0.5 N / tex), binder synthetic fiber (unstretched polyester fiber, fiber diameter 10.5 μm, The blending ratio of fiber length 5 mm, melting point 230 ° C., fine fiber (stretched polyester fiber, fiber diameter 6.4 μm, fiber length 5 mm, elongation 40%, tensile strength 0.5 N / tex) is 30:40: A semipermeable membrane support was obtained in the same manner as in Example 2 except that the number was 30.

(Example 29)
Large fiber (stretched polyester fiber, fiber diameter 14.3 μm, fiber length 5 mm, elongation 40%, tensile strength 0.5 N / tex), binder synthetic fiber (unstretched polyester fiber, fiber diameter 10.5 μm, The blending ratio of fiber length 5 mm, melting point 230 ° C., fine fiber (stretched polyester fiber, fiber diameter 6.4 μm, fiber length 5 mm, elongation 40%, tensile strength 0.5 N / tex) is 28:45: A semipermeable membrane supporting member was obtained in the same manner as in Example 2 except that it was 27.

  From the comparison between Example 2 and Examples 22 to 29, two or more main synthetic fibers and binder synthetic fibers having different fiber diameters are contained, and the binder synthetic fiber is contained with respect to the total mass of the main synthetic fiber and the binder synthetic fiber. In Examples 22 and 23 in which the rate was 20% by mass or less, a tendency for fuzz to increase was confirmed. Further, the semipermeable membrane support of Example 29 having a content of more than 40% by mass is semipermeable regardless of whether the X surface is a semipermeable membrane coated surface or the Y surface is a semipermeable membrane coated surface. The tendency for film adhesion and non-coated surface adhesion to deteriorate was confirmed. Moreover, it was sticking to a roll at the time of a hot press process, and was a practical use upper limit level.

  When judged comprehensively from the evaluation of fluffing, conditions during hot pressing, semipermeable membrane soaking, semipermeable membrane adhesion, non-coated surface adhesion, and wrinkles during semipermeable membrane application, the content is 20 mass. %, Which is more than 40% by mass and less than 40% by mass, was excellent, and Examples 2, 25 and 26 whose content was 25% by mass to 35% by mass were more excellent. In Examples 27 and 28 in which the content was 37% by mass and 40% by mass, a slight sticking to the roll was observed during hot pressing, but there was no practical problem.

(Example 30)
As the X-plane layer, large diameter fiber 1 (stretched polyester fiber, fiber diameter 17.5 μm, fiber length 5 mm, elongation 45%, tensile strength 0.40 N / tex), large diameter fiber 2 (stretched polyester fiber, Fiber diameter 12.5 μm, fiber length 5 mm, elongation 45%, tensile strength 0.40 N / tex), binder synthetic fiber (unstretched polyester fiber, fiber diameter 10.5 μm, fiber length 5 mm, melting point 260 ° C.), Fine fibers (stretched polyester fiber, fiber diameter 7.4 μm, fiber length 5 mm, elongation 40%, tensile strength 0.50 N / tex) are mixed and dispersed in water at a mixing ratio of 30: 30: 30: 10. And stored in a stock tank with a stirrer.

  Next, as the Y-plane layer, large diameter fiber 1 (stretched polyester fiber, fiber diameter 17.5 μm, fiber length 5 mm, elongation 45%, tensile strength 0.40 N / tex), large diameter fiber 2 (stretched polyester fiber) Fiber, fiber diameter 12.5 μm, fiber length 5 mm, elongation 45%, tensile strength 0.40 N / tex), binder synthetic fiber (unstretched polyester fiber, fiber diameter 10.5 μm, fiber length 5 mm, melting point 260 ° C. ), Fine fiber (stretched polyester fiber, fiber diameter 7.4 μm, fiber length 5 mm, elongation 40%, tensile strength 0.50 N / tex) mixed with water at a mixing ratio of 30: 30: 30: 10 Dispersed and stored in a stock tank having a stirring device separately from the dispersion for the X-plane layer.

Using a combination machine of inclined wire paper machine and circular paper machine, X surface layer is inclined wire paper machine, Y surface layer is circular paper machine, dry surface X surface layer 20g / m ² , Y surface layer After forming 60 g / m ² of wet paper web, the hot-press drying is performed so that the X-plane layer is in contact with a Yankee dryer having a surface temperature of 130 ° C. to obtain a paper sheet of 80 g / m ² basis weight. It was.

Sheet winding is installed in an unwinding device, and after 60 minutes from hot-pressure drying with a Yankee dryer, the sheet is calendered with a combination of a heated metal roll (225 ° C.) and an elastic roll (no heating) (first heat A pressure roll nip, roll nip pressure 736 N / cm), a calender device (second hot pressure roll nip, roll nip pressure 736 N / cm) of a combination of an elastic roll (no heating) and a heated metal roll (225 ° C.) arranged in series Using a device that is hot-pressed under conditions of a hot-pressing speed of 20 m / min (the fiber substrate passes through the second hot-pressing roll nip 12 seconds after passing through the first hot-pressing roll nip). A support was obtained.
The X surface was in contact with the metal roll surface with the second hot-pressing roll.

(Example 31)
As the X-plane layer, large diameter fiber 1 (stretched polyester fiber, fiber diameter 17.5 μm, fiber length 5 mm, elongation 45%, tensile strength 0.40 N / tex), large diameter fiber 2 (stretched polyester fiber, Fiber diameter 12.5 μm, fiber length 5 mm, elongation 45%, tensile strength 0.40 N / tex), binder synthetic fiber (unstretched polyester fiber, fiber diameter 10.5 μm, fiber length 5 mm, melting point 260 ° C.), Fine fibers (stretched polyester fiber, fiber diameter 7.4 μm, fiber length 5 mm, elongation 40%, tensile strength 0.50 N / tex) are mixed and dispersed in water at a blending ratio of 25: 30: 35: 10. And stored in a stock tank with a stirrer.

  Next, as the Y-plane layer, large diameter fiber 1 (stretched polyester fiber, fiber diameter 17.5 μm, fiber length 5 mm, elongation 45%, tensile strength 0.40 N / tex), large diameter fiber 2 (stretched polyester fiber) Fiber, fiber diameter 12.5 μm, fiber length 5 mm, elongation 45%, tensile strength 0.40 N / tex), binder synthetic fiber (unstretched polyester fiber, fiber diameter 10.5 μm, fiber length 5 mm, melting point 260 ° C. ), Fine fiber (drawn polyester fiber, fiber diameter 7.4 μm, fiber length 5 mm, elongation 40%, tensile strength 0.50 N / tex) mixed with water at a blending ratio of 35: 30: 25: 10 Dispersed and stored in a stock tank having a stirring device separately from the dispersion for the X-plane layer.

Using a combination machine of inclined wire paper machine and circular paper machine, X surface layer is inclined wire paper machine, Y surface layer is circular paper machine, dry surface X surface layer 20g / m ² , Y surface layer After forming 60 g / m ² of wet paper web, the hot-press drying is performed so that the X-plane layer is in contact with a Yankee dryer having a surface temperature of 130 ° C. to obtain a paper sheet of 80 g / m ² basis weight. It was.

  Sheet winding is installed in an unwinding device, and after 60 minutes from hot-pressure drying with a Yankee dryer, the sheet is calendered with a combination of a heated metal roll (225 ° C.) and an elastic roll (no heating) (first heat A pressure roll nip, roll nip pressure 736 N / cm), a calender device (second hot pressure roll nip, roll nip pressure 736 N / cm) of a combination of an elastic roll (no heating) and a heated metal roll (225 ° C.) arranged in series Using a device that is hot-pressed under conditions of a hot-pressing speed of 20 m / min (the fiber substrate passes through the second hot-pressing roll nip 12 seconds after passing through the first hot-pressing roll nip). A support was obtained. The X surface was in contact with the metal roll surface with the second hot-pressing roll.

(Example 32)
As the X-plane layer, large diameter fiber 1 (stretched polyester fiber, fiber diameter 17.5 μm, fiber length 5 mm, elongation 45%, tensile strength 0.40 N / tex), large diameter fiber 2 (stretched polyester fiber, Fiber diameter 12.5 μm, fiber length 5 mm, elongation 45%, tensile strength 0.40 N / tex), binder synthetic fiber (unstretched polyester fiber, fiber diameter 10.5 μm, fiber length 5 mm, melting point 260 ° C.), Fine fibers (stretched polyester fiber, fiber diameter 7.4 μm, fiber length 5 mm, elongation 40%, tensile strength 0.50 N / tex) are mixed and dispersed in water at a blending ratio of 25: 30: 35: 10. And stored in a stock tank with a stirrer.

  Next, as the Y-plane layer, large diameter fiber 1 (stretched polyester fiber, fiber diameter 17.5 μm, fiber length 5 mm, elongation 45%, tensile strength 0.40 N / tex), large diameter fiber 2 (stretched polyester fiber) Fiber, fiber diameter 12.5 μm, fiber length 5 mm, elongation 45%, tensile strength 0.40 N / tex), binder synthetic fiber (unstretched polyester fiber, fiber diameter 10.5 μm, fiber length 5 mm, melting point 260 ° C. ), Fine fiber (drawn polyester fiber, fiber diameter 7.4 μm, fiber length 5 mm, elongation 40%, tensile strength 0.50 N / tex) mixed with water at a blending ratio of 35: 30: 25: 10 Dispersed and stored in a stock tank having a stirring device separately from the dispersion for the X-plane layer.

Using a combination machine of inclined wire paper machine and circular paper machine, X surface layer is inclined wire paper machine, Y surface layer is circular paper machine, dry surface X surface layer 20g / m ² , Y surface layer After forming 60 g / m ² of wet paper web, the hot-press drying is performed so that the X-plane layer is in contact with a Yankee dryer having a surface temperature of 130 ° C. to obtain a paper sheet of 80 g / m ² basis weight. It was.

  Sheet winding is installed in an unwinding device, and after 60 minutes from hot-pressure drying with a Yankee dryer, the sheet is calendered with a combination of a heated metal roll (225 ° C.) and an elastic roll (no heating) (first heat A pressure roll nip, a roll nip pressure 736 N / cm), and a calender device (second hot pressure roll nip, roll nip pressure 736 N / cm) of a combination of a heated metal roll (225 ° C.) and a heated metal roll (225 ° C.) are arranged in series Is subjected to hot pressing under the conditions of a hot pressing speed of 20 m / min (the fiber substrate passes through the second hot pressing roll nip 12 seconds after passing through the first hot pressing roll nip). A membrane support was obtained. The X surface was in contact with the metal roll surface with the first and second hot-pressing rolls.

(Example 33)
As the X-plane layer, large-diameter fiber (stretched polyester fiber, fiber diameter 14.3 μm, fiber length 5 mm, elongation 45%, tensile strength 0.40 N / tex), binder synthetic fiber (unstretched polyester fiber, fiber) 37. diameter 10.5 μm, fiber length 5 mm, melting point 260 ° C.), thin fiber (stretched polyester fiber, fiber diameter 6.4 μm, fiber length 5 mm, elongation 40%, tensile strength 0.50 N / tex). It was mixed and dispersed in water at a mixing ratio of 5: 25: 37.5, and stored in a stock tank having a stirring device.

  Next, as the Y-plane layer, large-diameter fibers (stretched polyester fibers, fiber diameter 14.3 μm, fiber length 5 mm, elongation 45%, tensile strength 0.40 N / tex), binder synthetic fibers (unstretched polyester fibers) , Fiber diameter 10.5 μm, fiber length 5 mm, melting point 260 ° C.), thin fiber (stretched polyester fiber, fiber diameter 6.4 μm, fiber length 5 mm, elongation 40%, tensile strength 0.50 N / tex) It was mixed and dispersed in water at a mixing ratio of 37.5: 25: 37.5, and stored in a stock tank having a stirring device separately from the dispersion for the X-plane layer.

Using a combination machine of inclined wire paper machine and circular paper machine, X surface layer is inclined wire paper machine, uncoated surface layer is circular paper machine, X surface layer is 20g / m ² by dry mass, Y surface After forming a wet paper web having a layer of 60 g / m ² , it was hot-pressure dried so that the X-plane layer was in contact with a Yankee dryer having a surface temperature of 130 ° C. to prepare a paper sheet having a basis weight of 80 g / m ^2. Obtained.

  The obtained sheet was hot-pressed under the conditions of a temperature of 200 ° C., a pressure of 785 N / cm, and a processing speed of 30 m / min using a calendering device that is a combination of a heated metal roll and a heated metal roll, and a semipermeable membrane support was obtained. Obtained. The surface in contact with the Yankee dryer is the X surface.

(Example 34)
As the X-plane layer, large-diameter fiber (stretched polyester fiber, fiber diameter 14.3 μm, fiber length 5 mm, elongation 45%, tensile strength 0.40 N / tex), binder synthetic fiber (unstretched polyester fiber, fiber) Diameter: 10.5 μm, fiber length: 5 mm, melting point: 260 ° C.), fine fiber (stretched polyester fiber, fiber diameter: 6.4 μm, fiber length: 5 mm, elongation: 40%, tensile strength: 0.50 N / tex) 45: It was mixed and dispersed in water at a blending ratio of 35:20 and stored in a stock tank having a stirring device.

  Next, as the Y-plane layer, large-diameter fibers (stretched polyester fibers, fiber diameter 14.3 μm, fiber length 5 mm, elongation 45%, tensile strength 0.40 N / tex), binder synthetic fibers (unstretched polyester fibers) , Fiber diameter 10.5 μm, fiber length 5 mm, melting point 260 ° C.), thin fiber (stretched polyester fiber, fiber diameter 6.4 μm, fiber length 5 mm, elongation 40%, tensile strength 0.50 N / tex) It was mixed and dispersed in water at a mixing ratio of 20:35:45, and stored in a stock tank having a stirring device separately from the dispersion for the X-plane layer.

Using a combination machine of inclined wire paper machine and circular paper machine, X surface layer is inclined wire paper machine, Y surface layer is circular paper machine, X surface layer 20g / m ² by dry mass, non-coated surface After forming a wet paper web having a layer of 60 g / m ² , it was hot-pressure dried so that the X-plane layer was in contact with a Yankee dryer having a surface temperature of 130 ° C. to prepare a paper sheet having a basis weight of 80 g / m ^2. Obtained.

  The obtained sheet was hot-pressed under the conditions of a temperature of 200 ° C., a pressure of 785 N / cm, and a processing speed of 30 m / min using a calendering device that is a combination of a heated metal roll and a heated metal roll, and a semipermeable membrane support was obtained. Obtained. The surface in contact with the Yankee dryer is the X surface.

(Example 35)
As the X-plane layer, large-diameter fiber (stretched polyester fiber, fiber diameter 14.3 μm, fiber length 5 mm, elongation 45%, tensile strength 0.40 N / tex), binder synthetic fiber (unstretched polyester fiber, fiber) Diameter 10.5 μm, fiber length 5 mm, melting point 260 ° C.), fine fiber (stretched polyester fiber, fiber diameter 6.4 μm, fiber length 5 mm, elongation 40%, tensile strength 0.50 N / tex) 20: It was mixed and dispersed in water at a mixing ratio of 30:50 and stored in a stock tank having a stirring device.

  Next, as the Y-plane layer, large-diameter fibers (stretched polyester fibers, fiber diameter 14.3 μm, fiber length 5 mm, elongation 45%, tensile strength 0.40 N / tex), binder synthetic fibers (unstretched polyester fibers) , Fiber diameter 10.5 μm, fiber length 5 mm, melting point 260 ° C.), thin fiber (stretched polyester fiber, fiber diameter 6.4 μm, fiber length 5 mm, elongation 40%, tensile strength 0.50 N / tex) It was mixed and dispersed in water at a blending ratio of 50:30:20, and stored in a stock tank having a stirrer separately from the dispersion for the X-plane layer.

Using a combination machine of inclined wire paper machine and circular paper machine, X surface layer is inclined wire paper machine, uncoated surface layer is circular paper machine, X surface layer is 20g / m ² by dry mass, Y surface After forming a wet paper web having a layer of 60 g / m ² , it was hot-pressure dried so that the X-plane layer was in contact with a Yankee dryer having a surface temperature of 130 ° C. to prepare a paper sheet having a basis weight of 80 g / m ^2. Obtained.

  The obtained sheet was hot-pressed under the conditions of a temperature of 200 ° C., a pressure of 785 N / cm, and a processing speed of 30 m / min using a calendering device that is a combination of a heated metal roll and a heated metal roll, and a semipermeable membrane support was obtained. Obtained. The surface in contact with the Yankee dryer is the X surface.

  From comparison between Examples 30 to 32 and Examples 33 to 35, two or more kinds of main synthetic fibers and binder synthetic fibers having different fiber diameters were contained, and two-layer structure was subjected to two hot pressing processes. The semipermeable membrane support of Examples 30 to 32 has a semipermeable membrane permeation, semipermeable membrane adhesion, even when the X surface is a semipermeable membrane coated surface or the Y surface is a semipermeable membrane coated surface. It was excellent in all evaluations of non-coated surface adhesiveness and wrinkles during semipermeable membrane coating.

(Comparative Example 5)
Main synthetic fiber (stretched polyester fiber, fiber diameter 24.7 μm, fiber length 5 mm, elongation 40%, tensile strength 0.50 N / tex), binder synthetic fiber (unstretched polyester fiber, fiber diameter 10.5 μm, (Fiber length 5 mm, melting point 230 ° C.) is mixed and dispersed in water at a blending ratio of 70:30, wet paper is formed with a circular paper machine, and then hot-pressure dried with a Yankee dryer having a surface temperature of 130 ° C. An 80 g / m ² sheet was obtained.

  The obtained sheet was hot-pressed under the conditions of a temperature of 200 ° C., a pressure of 785 N / cm, and a processing speed of 60 m / min using a calendering device that is a combination of a heated metal roll and a heated metal roll. Obtained. In addition, the surface which contacted the Yankee dryer was made into the X surface.

(Comparative Example 6)
A semipermeable membrane support was obtained in the same manner as in Comparative Example 5, except that the processing speed during hot pressing was 120 m / min.

(Comparative Example 7)
A semipermeable membrane support was obtained in the same manner as in Comparative Example 5 except that the processing speed during hot pressing was 30 m / min.

(Comparative Example 8)
A semipermeable membrane support was obtained in the same manner as in Comparative Example 5, except that the processing speed during hot pressing was 6 m / min.

(Comparative Example 9)
A semipermeable membrane support was obtained in the same manner as in Comparative Example 5 except that the processing speed during hot pressing was 2 m / min.

  In the semipermeable membrane supports of Comparative Examples 5 to 9 containing only one type of main synthetic fiber, the cross-sectional aspect ratio of the main synthetic fibers existing from the surface of the semipermeable membrane application surface to 1/3 Moreover, regardless of the numerical value of the cross-sectional aspect ratio of the main synthetic fiber existing 1/3 from the surface of the non-coated surface, there was a tendency for fuzz to increase and the evaluation result of the semipermeable membrane soaking was poor.

(Comparative Example 10)
Main synthetic fiber (stretched polyester fiber, fiber diameter 11.6 μm, fiber length 5 mm, elongation 40%, tensile strength 0.50 N / tex), binder synthetic fiber (unstretched polyester fiber, fiber diameter 14.3 μm, Fiber length 5mm, melting point 260 ° C) was mixed and dispersed in water at a blending ratio of 80:20, wet paper was formed with a circular paper machine, and then hot-pressure dried with a Yankee dryer with a surface temperature of 130 ° C, and the basis weight An 80 g / m ² sheet was obtained.

  Sheet winding is installed in the unwinding device, and the sheet is combined with a cotton roll, a heated metal roll (170 ° C.), and a heated metal roll (170 ° C.) like a super calender (first hot pressure) The roll nip and the second hot-press roll nip are continuous), and the hot-press processing is performed under the conditions of the first and second hot-press roll nip pressure of 1000 N / cm and the processing speed of 5 m / min to obtain a semipermeable membrane support. It was. The surface in contact with the heated metal roll surface of the second hot-press roll nip was defined as the X surface.

(Comparative Example 11)
Main synthetic fiber (drawn polyester fiber, fiber diameter 12.5 μm, fiber length 5 mm, elongation 40%, tensile strength 0.50 N / tex), binder synthetic fiber (core-sheath type polyester fiber, fiber diameter 10.5 μm) Fiber length: 5 mm, sheath melting point 107 ° C.) is mixed and dispersed in water at a blending ratio of 80:20, wet paper is formed with a circular net paper machine, and then hot-pressure dried with a Yankee dryer having a surface temperature of 130 ° C. And a sheet having a basis weight of 80 g / m ² was obtained.

  The obtained sheet was hot-pressed under the conditions of a heated metal roll temperature of 160 ° C., a pressure of 2000 N / cm, and a processing speed of 30 m / min, using a calender device in combination of a heated metal roll and a cotton roll (no heating). A semipermeable membrane support was obtained. The surface in contact with the heated metal roll was taken as the X surface.

(Comparative Example 12)
Main synthetic fiber (acrylic fiber, fiber diameter 22.5 μm, fiber length 5 mm, elongation 40%, tensile strength 0.40 N / tex), binder synthetic fiber (unstretched polyester fiber, fiber diameter 14.3 μm, fiber length 5 mm, melting point 260 ° C.) was mixed and dispersed in water at a blending ratio of 80:20, and wet paper was formed with a circular paper machine, followed by hot-pressure drying with a Yankee dryer having a surface temperature of 130 ° C., and a basis weight of 80 g / An m ² sheet was obtained.

  The obtained sheet was hot-pressed under the conditions of a heated metal roll temperature of 225 ° C., a pressure of 1000 N / cm, and a processing speed of 20 m / min, using a calender device that was a combination of a heated metal roll and elasticity (no heating). A permeable membrane support was obtained. The surface in contact with the heated metal roll was taken as the X surface.

(Comparative Example 13)
As the X-plane layer, a main synthetic fiber (stretched polyester fiber having a cross-sectional shape of trilobal (triangle), fiber diameter 12.5 μm, fiber length 5 mm, elongation 45%, tensile strength 0.4 N / tex), binder Synthetic fiber (unstretched polyester fiber, fiber diameter 10.5 μm, fiber length 5 mm, melting point 260 ° C.) is mixed and dispersed in water at a blending ratio of 60:40, and wet paper is formed on a circular net paper machine. It was hot-pressure dried with a Yankee dryer having a temperature of 130 ° C. to obtain a sheet having a basis weight of 40 g / m ² .

As the Y-plane layer, the main synthetic fiber (stretched polyester fiber, fiber diameter 7.4 μm, fiber length 5 mm, elongation 45%, tensile strength 0.4 N / tex), binder synthetic fiber (unstretched polyester fiber, fiber) 10.5 μm in diameter, fiber length 5 mm, melting point 260 ° C.) is mixed and dispersed in water at a blending ratio of 60:40, wet paper is formed with a circular paper machine, and then hot pressure is applied with a Yankee dryer having a surface temperature of 130 ° C. The sheet was dried to obtain a sheet having a basis weight of 40 g / m ² .

  The obtained X-plane layer and Y-plane layer are overlapped, and using a calender device that is a combination of a heated metal roll and a heated metal roll, hot pressing is performed at a temperature of 220 ° C., a pressure of 980 N / cm, and a processing speed of 5 m / min. Thus, a semipermeable membrane support was obtained.

  In the semipermeable membrane support of Comparative Examples 10 to 12, which contains only one type of main synthetic fiber and the blending ratio of the binder synthetic fiber is 20%, from the surface of the semipermeable membrane application surface Although the cross-sectional aspect ratio of the main synthetic fiber existing up to 1/3 and the cross-sectional aspect ratio of the main synthetic fiber existing up to 1/3 from the surface of the non-coated surface are 1.2 to 3.0, there are many fluffs The level was not practical. Moreover, when the Y surface was a semipermeable membrane application surface, in Comparative Examples 11 and 12, the semipermeable membrane soaking was bad.

  The X-plane layer contains only one type of principal synthetic fiber having a cross-sectional shape of trilobal (triangle), the Y-plane layer contains only one type of principal synthetic fiber, and a binder. In the semipermeable membrane supporting material of Comparative Example 13 in which the blending ratio of the synthetic fiber was 40% by mass, the formation of the X-plane layer sheet was poor. Moreover, the cross-sectional aspect ratio of the main synthetic fiber existing from the surface of the semipermeable membrane application surface to 1/3 and the cross-sectional aspect ratio of the main synthetic fiber existing from the surface of the non-application surface to 1/3 are 1.2 to Although it was 3.0, the non-coated surface adhesiveness when the X surface was a semipermeable membrane coated surface and the semipermeable membrane adhesive property when the Y surface was a semipermeable membrane coated surface were unpractical levels. .

(Example 36)
Large diameter fiber (acrylic fiber, fiber diameter 14.3 μm, fiber length 5 mm, elongation 40%, tensile strength 0.40 N / tex), binder synthetic fiber (unstretched polyester fiber, fiber diameter 10.5 μm, fiber length 5 mm, melting point 230 ° C.), fine fiber (acrylic fiber, fiber diameter 6.4 μm, fiber length 5 mm, elongation 40%, tensile strength 0.40 N / tex) in water at a mixing ratio of 35:30:35 After mixing and dispersing and forming wet paper with a circular paper machine, it was hot-pressure dried with a Yankee dryer having a surface temperature of 130 ° C. to obtain a sheet having a basis weight of 80 g / m ² .

  The obtained sheet was hot-pressed under the conditions of a temperature of 200 ° C., a pressure of 785 N / cm, and a processing speed of 30 m / min using a calendering device that is a combination of a heated metal roll and a heated metal roll, and a semipermeable membrane support was obtained. Obtained. In addition, the surface which contacted the Yankee dryer was made into the X surface.

(Example 37)
Fine fiber (stretched polyester fiber, fiber diameter 6.6 μm, fiber length 10 mm, elongation 45%, tensile strength 0.50 N / tex), large fiber (stretched polyester fiber, fiber diameter 12.5 μm, fiber 5 mm in length, 45% elongation, tensile strength 0.50 N / tex), binder synthetic fiber 1 (unstretched polyester fiber, fiber diameter 10.1 μm, fiber length 5 mm, melting point 191 ° C.), binder synthetic fiber 2 (core) Sheath-type polyester fiber, fiber diameter 14.3 μm, fiber length: 5 mm, sheath melting point 107 ° C.) is mixed and dispersed in water at a blending ratio of 20.4: 40.7: 36.6: 2.3. After forming wet paper with a net paper machine, it was hot-pressure dried with a Yankee dryer having a surface temperature of 130 ° C. to obtain a sheet having a basis weight of 80 g / m ² .

  The obtained sheet was hot-pressed under the conditions of a temperature of 225 ° C., a pressure of 785 N / cm, and a processing speed of 20 m / min using a calender device that is a combination of a heated metal roll and a heated metal roll. Obtained. The surface in contact with the Yankee dryer was used as the semipermeable membrane application surface.

(Example 38)
Large diameter fiber (stretched polyester fiber, fiber diameter 17.5 μm, fiber length 5 mm, aspect ratio 286, elongation 45%, tensile strength 0.50 N / tex), binder synthetic fiber (unstretched polyester fiber, fiber diameter) 10.5 μm, fiber length 5 mm, melting point 260 ° C., fine fiber (stretched polyester fiber, fiber diameter 12.5 μm, fiber length 5 mm, aspect ratio 399, elongation 45%, tensile strength 0.50 N / tex) Was mixed and dispersed in water at a mixing ratio of 30:40:30, wet paper was formed with a circular paper machine, and then hot-pressure dried with a Yankee dryer having a surface temperature of 130 ° C., and a sheet having a basis weight of 34 g / m ² . C was obtained.

  The obtained sheet was hot-pressed under the conditions of a temperature of 225 ° C., a pressure of 588 N / cm, and a processing speed of 25 m / min using a calender device that is a combination of a heated metal roll and an elastic roll, and a nonwoven fabric C was obtained.

Next, large diameter fiber (stretched polyester fiber, fiber diameter 17.5 μm, fiber length 5 mm, aspect ratio 286, elongation 45%, tensile strength 0.50 N / tex), binder synthetic fiber (unstretched polyester fiber, A fiber diameter of 10.5 μm, fiber length of 5 mm, melting point of 260 ° C.) was mixed and dispersed in water at a blending ratio of 60:40, wet paper was formed with a circular paper machine, and then heated with a Yankee dryer with a surface temperature of 130 ° C. Pressure-drying was performed to obtain a sheet D having a basis weight of 34 g / m ² .

In the calender device of the combination of the heated metal roll and the elastic roll, the nonwoven fabric C and the sheet D are overlapped with the nonwoven fabric C as the X plane layer and the nonwoven fabric C and the sheet D are overlapped. Hot pressing under the conditions of a metal roll temperature of 225 ° C., a pressure of 588 N / cm, and a processing speed of 25 m / min, the basis weight ratio of the X plane layer and the Y plane layer is 1: 1, and the total basis weight is 70 g / m ² A permeable membrane support was obtained.

(Example 39)
Fine fiber (stretched polyester fiber, fiber diameter 12.5 μm, fiber length 5 mm, elongation 45%, tensile strength 0.50 N / tex), binder synthetic fiber (unstretched polyester fiber, fiber diameter 10.5 μm, (Fiber length 5 mm, melting point 260 ° C.) is mixed and dispersed in water at a blending ratio of 60:40, and wet paper is formed by a circular paper machine, followed by hot-pressure drying with a Yankee dryer having a surface temperature of 130 ° C. A sheet E of 40 g / m ² was obtained.

Subsequently, a thick fiber (stretched polyester fiber, fiber diameter 22.5 μm, fiber length 5 mm, elongation 45%, tensile strength 0.50 N / tex), binder synthetic fiber (unstretched polyester fiber, fiber diameter 10. 5 μm, fiber length 5 mm, melting point 260 ° C.) were mixed and dispersed in water at a blending ratio of 60:40, wet paper was formed with a circular net paper machine, and then hot-pressure dried with a Yankee dryer having a surface temperature of 130 ° C. A sheet F having a basis weight of 50 g / m ² was obtained.

The sheet E is a non-coated surface layer, the sheet F is an X-plane layer, the sheet E and the sheet F are overlapped, and a calender device of a combination of a heated metal roll and an elastic roll is used. After processing at a processing speed of 30 m / min, in the calender device of the combination of the heated metal roll and the elastic roll so that the first surface in contact with the heated metal roll is in contact with the elastic roll, the heated metal roll temperature is 226 ° C., the pressure The film was hot-pressed under conditions of 980 N / cm and a processing speed of 30 m / min to obtain a semipermeable membrane support having a basis weight ratio of 5: 4 for the X plane layer and the Y plane layer and a total basis weight of 90 g / m ² . .

(Example 40)
Sheets with a two-layer structure were produced using a combination machine of an inclined wire type paper machine and a circular net paper machine. Fine fiber (stretched polyester fiber, fiber diameter 11.6 μm, fiber length 5 mm, elongation 45%, tensile strength 0.50 N / tex), binder synthetic fiber (unstretched polyester fiber, fiber diameter 10.5 μm, Fiber length 5 mm, melting point 260 ° C.) was mixed and dispersed in water at a blending ratio of 55:45, and a wet paper with a Y-coated surface layer was formed with an inclined wire type paper machine.

Large fiber (stretched polyester fiber, fiber diameter 20.2 μm, fiber length 10 mm, elongation 45%, tensile strength 0.50 N / tex), binder synthetic fiber (unstretched polyester fiber, fiber diameter 10.5 μm, A fiber length of 5 mm and a melting point of 260 ° C. is mixed and dispersed in water at a blending ratio of 55:45. After forming a wet paper with an X-plane layer with a circular paper machine, the two wet papers are made together and a surface temperature of 130 is obtained. Drying was carried out with a Yankee dryer at 0 ° C. to obtain a sheet having a basis weight ratio of X-plane layer and Y-plane layer of 1: 1 and a total basis weight of 103 g / m ² .

  After the obtained sheet was processed under the conditions of a heated metal roll temperature of 230 ° C., a pressure of 785 N / cm, and a processing speed of 10 m / min in a calender device of a combination of a heated metal roll and a cotton roll, In a calender device with a combination of a heated metal roll and a cotton roll so that the surface in contact is in contact with the cotton roll, heat pressing is performed under the conditions of a heated metal roll temperature of 200 ° C., a pressure of 785 N / cm, and a processing speed of 10 m / min. A membrane support was obtained. The X plane layer was in contact with the cotton roll for the first time.

  From the comparison of the semipermeable membrane adhesive properties in Example 2 and Example 36, it was confirmed that Example 2 using polyester fiber was superior to Example 36 using acrylic fiber.

  Since the semipermeable membrane support of Example 37 uses a low-melting core-sheath type polyester fiber as the binder synthetic fiber, it exits from the nip between the heated metal roll and the heated metal roll during hot pressing. At that time, sticking occurred, and the semipermeable membrane adhesiveness reached a practically lower limit level.

  The semipermeable membrane supporting materials of Examples 38 to 40 are non-woven fabrics having a two-layer structure, but included a layer having one kind of main synthetic fiber, and the formation of the layer was poor. Moreover, since the semipermeable membrane support of Example 40 uses fibers having a fiber length of 10 mm, the formation was further worse than the semipermeable membrane supports of Examples 38 and 39. In Examples 38 and 39 in which the content of the binder synthetic fiber was 40% by mass, some sticking to the roll was observed during hot pressing. In Example 40 in which the content was 45% by mass, sticking to the roll during hot pressing was caused, and the semipermeable membrane adhesiveness was practically at the lower limit level.

(Example 41)
Large diameter fiber (stretched polyester fiber, fiber diameter 14.3 μm, fiber length 5 mm, elongation 45%, tensile strength 0.40 N / tex), binder synthetic fiber (unstretched polyester fiber, fiber diameter 10.5 μm, Fiber length 5mm, melting point 230 ° C), fine fiber (stretched polyester fiber, fiber diameter 6.4μm, fiber length 5mm, elongation 45%, tensile strength 0.40N / tex) 35:30:35 After mixing and dispersing in water at a ratio and forming wet paper with a circular paper machine, it was hot-pressure dried with a Yankee dryer having a surface temperature of 130 ° C. to obtain a sheet having a basis weight of 80 g / m ² .

  The obtained sheet was hot-pressed under the conditions of a temperature of 200 ° C., a pressure of 785 N / cm, and a processing speed of 110 m / min using a calendering device of a combination of a heated metal roll and a heated metal roll, and a semipermeable membrane support was obtained. Obtained. In addition, the surface which contacted the Yankee dryer was made into the X surface.

(Example 42)
Large diameter fiber (stretched polyester fiber, fiber diameter 14.3 μm, fiber length 5 mm, elongation 45%, tensile strength 0.40 N / tex), binder synthetic fiber (unstretched polyester fiber, fiber diameter 10.5 μm, Fiber length 5mm, melting point 230 ° C), fine fiber (stretched polyester fiber, fiber diameter 6.4μm, fiber length 5mm, elongation 45%, tensile strength 0.40N / tex) 35:30:35 After mixing and dispersing in water at a ratio and forming wet paper with a circular paper machine, it was hot-pressure dried with a Yankee dryer having a surface temperature of 130 ° C. to obtain a sheet having a basis weight of 80 g / m ² .

  The obtained sheet was hot-pressed under the conditions of a temperature of 200 ° C., a pressure of 980 N / cm, and a processing speed of 2 m / min, using a calender device in which a heated metal roll and a heated metal roll were combined. Obtained. The surface not in contact with the Yankee dryer was designated as the X surface.

  From a comparison of Examples 2, 41 and 42, the semipermeable membrane supporting material of Example 41 having a cross-sectional aspect ratio of 1.1 on the Y-side main synthetic fiber is a semi-permeable membrane in which the Y surface is a semipermeable membrane coated surface. The permeation of the permeable membrane was bad. In addition, the semipermeable membrane support of Example 42 in which the cross-sectional aspect ratio of the main synthetic fiber on the Y plane was 3.2 had poor non-coated surface adhesion when the X plane was a semipermeable membrane coated surface.

(Example 43)
Large diameter fiber (stretched polyester fiber, 48% elongation, tensile strength 0.41 N / tex, fiber diameter 18.2 μm, fiber length 5 mm), binder synthetic fiber (unstretched polyester fiber, fiber diameter 10.5 μm, Fiber length 5mm, melting point 230 ° C), fine fiber (stretched polyester fiber, elongation 48%, tensile strength 0.41N / tex, fiber diameter 10.5μm, fiber length 5mm) 60:30:10 After mixing and dispersing in water at a ratio and forming wet paper with a circular paper machine, it was hot-pressure dried with a Yankee dryer having a surface temperature of 130 ° C. to obtain a sheet having a basis weight of 80 g / m ² .

  One sheet of the heated metal was niped with a calendering device using a calendering device of a combination of a heating metal roll and a heating metal roll at a temperature of 200 ° C., a pressure of 980 N / cm, and a processing speed of 25 m / min. A semi-permeable membrane support was obtained by holding the roll and hot pressing so that one surface was heated more. In addition, it heat-presses so that it may contact the metal roll surface which held the surface which does not contact a Yankee dryer, the surface which contacted the held metal roll surface is made into X surface, and the surface on the opposite side is made into Y surface.

(Example 44)
Large fiber (stretched polyester fiber, 23% elongation, tensile strength 0.75 N / tex, fiber diameter 18.2 μm, fiber length 5 mm), binder synthetic fiber (unstretched polyester fiber, fiber diameter 6.8 μm, Fiber length 5 mm, melting point 230 ° C.), fine fiber (stretched polyester fiber, elongation 23%, tensile strength 0.75 N / tex, fiber diameter 8.6 μm, fiber length 5 mm) 60:30:10 After mixing and dispersing in water at a ratio and forming wet paper with a circular paper machine, it was hot-pressure dried with a Yankee dryer having a surface temperature of 130 ° C. to obtain a sheet having a basis weight of 80 g / m ² .

  One sheet of the heated metal was niped with a calendering device using a calendering device of a combination of a heating metal roll and a heating metal roll at a temperature of 200 ° C., a pressure of 780 N / cm, and a processing speed of 20 m / min. A semi-permeable membrane support was obtained by holding the roll and hot pressing so that one surface was heated more. In addition, it heat-presses so that it may contact the metal roll surface which held the surface which does not contact a Yankee dryer, the surface which contacted the held metal roll surface is made into X surface, and the surface on the opposite side is made into Y surface.

(Example 45)
Large fiber (stretched polyester fiber, elongation 80%, tensile strength 0.51 N / tex, fiber diameter 18.2 μm, fiber length 5 mm), binder synthetic fiber (unstretched polyester fiber, fiber diameter 10.5 μm, 60:30:10, fiber length 5 mm, melting point 230 ° C., fine fiber (stretched polyester fiber, elongation 80%, tensile strength 0.51 N / tex, fiber diameter 8.6 μm, fiber length 5 mm) After mixing and dispersing in water at a ratio and forming wet paper with a circular paper machine, it was hot-pressure dried with a Yankee dryer having a surface temperature of 130 ° C. to obtain a sheet having a basis weight of 80 g / m ² .

  One sheet of the heated metal was niped with a calendering device using a calendering device of a combination of a heating metal roll and a heating metal roll at a temperature of 200 ° C., a pressure of 780 N / cm, and a processing speed of 20 m / min. A semi-permeable membrane support was obtained by holding the roll and hot pressing so that one surface was heated more. In addition, it heat-presses so that it may contact the metal roll surface which held the surface which does not contact a Yankee dryer, the surface which contacted the held metal roll surface is made into X surface, and the surface on the opposite side is made into Y surface.

(Example 46)
Large diameter fiber (stretched polyester fiber, elongation 60%, tensile strength 0.36 N / tex, fiber diameter 18.2 μm, fiber length 5 mm), binder synthetic fiber (unstretched polyester fiber, fiber diameter 10.5 μm, Fiber length 5 mm, melting point 230 ° C.), fine fiber (stretched polyester fiber, elongation 60%, tensile strength 0.36 N / tex, fiber diameter 8.6 μm, fiber length 5 mm) 60:30:10 After mixing and dispersing in water at a ratio and forming wet paper with a circular paper machine, it was hot-pressure dried with a Yankee dryer having a surface temperature of 130 ° C. to obtain a sheet having a basis weight of 80 g / m ² .

  One sheet of the heated metal was niped with a calendering device using a calendering device of a combination of a heating metal roll and a heating metal roll at a temperature of 200 ° C., a pressure of 980 N / cm, and a processing speed of 25 m / min. A semi-permeable membrane support was obtained by holding the roll and hot pressing so that one surface was heated more. In addition, it heat-presses so that it may contact the metal roll surface which held the surface which does not contact a Yankee dryer, the surface which contacted the held metal roll surface is made into X surface, and the surface on the opposite side is made into Y surface.

(Example 47)
Large fiber (stretched polyester fiber, elongation 120%, tensile strength 0.31 N / tex, fiber diameter 18.2 μm, fiber length 5 mm), binder synthetic fiber (unstretched polyester fiber, fiber diameter 6.8 μm, Fiber length 5 mm, melting point 230 ° C.), fine fiber (stretched polyester fiber, elongation 120%, tensile strength 0.31 N / tex, fiber diameter 8.6 μm, fiber length 5 mm) 60:30:10 After mixing and dispersing in water at a ratio and forming wet paper with a circular paper machine, it was hot-pressure dried with a Yankee dryer having a surface temperature of 130 ° C. to obtain a sheet having a basis weight of 80 g / m ² .

  One sheet of the heated metal was niped with a calendering device using a calendering device of a combination of a heating metal roll and a heating metal roll at a temperature of 200 ° C., a pressure of 780 N / cm, and a processing speed of 20 m / min. A semi-permeable membrane support was obtained by holding the roll and hot pressing so that one surface was heated more. In addition, it heat-presses so that it may contact the metal roll surface which held the surface which does not contact a Yankee dryer, the surface which contacted the held metal roll surface is made into X surface, and the surface on the opposite side is made into Y surface.

(Example 48)
Large diameter fiber (stretched polyester fiber, elongation 140%, tensile strength 0.26 N / tex, fiber diameter 18.2 μm, fiber length 5 mm), binder synthetic fiber (unstretched polyester fiber, fiber diameter 6.8 μm, Fiber length 5 mm, melting point 230 ° C.), fine fiber (stretched polyester fiber, elongation 140%, tensile strength 0.26 N / tex, fiber diameter 8.6 μm, fiber length 5 mm) 60:30:10 After mixing and dispersing in water at a ratio and forming wet paper with a circular paper machine, it was hot-pressure dried with a Yankee dryer having a surface temperature of 130 ° C. to obtain a sheet having a basis weight of 80 g / m ² .

  One sheet of the heated metal was niped with a calendering device using a calendering device of a combination of a heating metal roll and a heating metal roll at a temperature of 200 ° C., a pressure of 780 N / cm, and a processing speed of 20 m / min. A semi-permeable membrane support was obtained by holding the roll and hot pressing so that one surface was heated more. In addition, it heat-presses so that it may contact the metal roll surface which held the surface which does not contact a Yankee dryer, the surface which contacted the held metal roll surface is made into X surface, and the surface on the opposite side is made into Y surface.

(Example 49)
Large fiber (stretched polyester fiber, elongation 30%, tensile strength 0.44 N / tex, fiber diameter 18.2 μm, fiber length 5 mm), binder synthetic fiber (unstretched polyester fiber, fiber diameter 6.8 μm, Fiber length 5mm, melting point 230 ° C), fine fiber (stretched polyester fiber, elongation 30%, tensile strength 0.44N / tex, fiber diameter 8.6μm, fiber length 5mm) 60:30:10 After mixing and dispersing in water at a ratio and forming wet paper with a circular paper machine, it was hot-pressure dried with a Yankee dryer having a surface temperature of 130 ° C. to obtain a sheet having a basis weight of 80 g / m ² .

  One sheet of heated metal was niped with a calendering device using a calendering device of a combination of a heating metal roll and a heating metal roll at a temperature of 200 ° C., a pressure of 785 N / cm, and a processing speed of 20 m / min. Hold the roll and hot-press it so that one side is heated more, and then wrap the two heated metal rolls at 120 ° C that are not niped in an S shape to make a winding, A permeable membrane support was obtained. In addition, it heat-presses so that it may contact the metal roll surface which held the surface which does not contact a Yankee dryer, the surface which contacted the held metal roll surface is made into X surface, and the surface on the opposite side is made into Y surface.

(Example 50)
Large diameter fiber (stretched polyester fiber, elongation 48%, tensile strength 0.41 N / tex, fiber diameter 17.5 μm, fiber length 5 mm), binder synthetic fiber (unstretched polyester fiber, fiber diameter 10.5 μm, Fiber length 5mm, melting point 230 ° C), fine fiber (stretched polyester fiber, elongation 50%, tensile strength 0.51N / tex, fiber diameter 11.6μm, fiber length 5mm) 30:30:40 After mixing and dispersing in water at a ratio and forming wet paper with a circular paper machine, it was hot-pressure dried with a Yankee dryer having a surface temperature of 130 ° C. to obtain a sheet having a basis weight of 80 g / m ² .

  One sheet of heated metal was niped with a calendering device using a calendering device of a combination of a heating metal roll and a heating metal roll at a temperature of 200 ° C., a pressure of 785 N / cm, and a processing speed of 20 m / min. A semi-permeable membrane support was obtained by holding the roll and hot pressing so that one surface was heated more. In addition, it heat-presses so that it may contact the metal roll surface which held the surface which does not contact a Yankee dryer, the surface which contacted the held metal roll surface is made into X surface, and the surface on the opposite side is made into Y surface.

(Example 51)
Sheets with a two-layer structure were produced using a combination machine of an inclined wire type paper machine and a circular net paper machine. Large diameter fiber (stretched polyester fiber, elongation 48%, tensile strength 0.41 N / tex, fiber diameter 17.5 μm, fiber length 5 mm), binder synthetic fiber (unstretched polyester fiber, fiber diameter 10.5 μm, Fiber length 5mm, melting point 230 ° C), fine fiber (stretched polyester fiber, elongation 50%, tensile strength 0.51N / tex, fiber diameter 11.6μm, fiber length 5mm) 30:30:40 The mixture was dispersed in water at a ratio, and a Y-layer wet paper was formed with an inclined wire type paper machine.

Large diameter fiber (stretched polyester fiber, elongation 50%, tensile strength 0.51 N / tex, fiber diameter 11.6 μm, fiber length 5 mm), binder synthetic fiber (unstretched polyester fiber, fiber diameter 10.5 μm, Fiber length 5 mm, melting point 230 ° C.), fine fiber (stretched polyester fiber, elongation 45%, tensile strength 0.41 N / tex, fiber diameter 8.6 μm, fiber length 5 mm) 40:30:30 After mixing and dispersing in water at a ratio and forming a wet paper web with an X-face layer with a circular paper machine, the two wet paper sheets are combined, dried with a Yankee dryer with a surface temperature of 130 ° C, and dried with a Y-face layer. A sheet having a basis weight ratio of 1: 1 and X plane layer of 1: 1 and a total basis weight of 80 g / m ² was obtained. In addition, it heat-dried so that X surface might touch a Yankee dryer.

  The obtained sheet was hot-pressed under the conditions of a temperature of 200 ° C., a pressure of 785 N / cm, and a processing speed of 20 m / min, using a calender device that is a combination of a heated metal roll and a heated metal roll, and a semipermeable membrane support was obtained. Obtained.

(Example 52)
Sheets with a two-layer structure were produced using a combination machine of an inclined wire type paper machine and a circular net paper machine. Large diameter fiber (stretched polyester fiber, elongation 48%, tensile strength 0.41 N / tex, fiber diameter 17.5 μm, fiber length 5 mm), binder synthetic fiber (unstretched polyester fiber, fiber diameter 10.5 μm, Fiber length 5mm, melting point 260 ° C), fine fiber (stretched polyester fiber, elongation 50%, tensile strength 0.51N / tex, fiber diameter 11.6μm, fiber length 5mm) 30:30:40 The mixture was dispersed in water at a ratio, and a Y-layer wet paper was formed with an inclined wire type paper machine.

Large diameter fiber (stretched polyester fiber, elongation 50%, tensile strength 0.51 N / tex, fiber diameter 11.6 μm, fiber length 5 mm), binder synthetic fiber (unstretched polyester fiber, fiber diameter 10.5 μm, Fiber length 5mm, melting point 260 ° C), fine fiber (stretched polyester fiber, elongation 45%, tensile strength 0.41N / tex, fiber diameter 8.6μm, fiber length 5mm) 40:30:30 After mixing and dispersing in water at a ratio and forming a wet paper web with an X-face layer with a circular paper machine, the two wet paper sheets are combined, dried with a Yankee dryer with a surface temperature of 130 ° C, and dried with a Y-face layer. A sheet having a basis weight ratio of 1: 1 and X plane layer of 1: 1 and a total basis weight of 80 g / m ² was obtained. In addition, it heat-dried so that X surface might touch a Yankee dryer.

  The obtained sheet was subjected to hot-pressure processing (first heat treatment) using a calender device combining a heated metal roll and an elastic roll (no heating) at a temperature of 225 ° C., a pressure of 980 N / cm, and a processing speed of 25 m / min. Pressure roll nip), and further hot pressing under the same conditions with the front and back reversed (second hot pressure roll nip), a semipermeable membrane support was obtained.

(Example 53)
Sheets with a two-layer structure were produced using a combination machine of an inclined wire type paper machine and a circular net paper machine. Large diameter fiber (stretched polyester fiber, elongation 48%, tensile strength 0.41 N / tex, fiber diameter 17.5 μm, fiber length 5 mm), binder synthetic fiber (unstretched polyester fiber, fiber diameter 10.5 μm, Fiber length 5mm, melting point 260 ° C), fine fiber (stretched polyester fiber, elongation 50%, tensile strength 0.51N / tex, fiber diameter 11.6μm, fiber length 5mm) 30:30:40 The mixture was dispersed in water at a ratio, and a Y-layer wet paper was formed with an inclined wire type paper machine.

Large diameter fiber (stretched polyester fiber, elongation 50%, tensile strength 0.51 N / tex, fiber diameter 11.6 μm, fiber length 5 mm), binder synthetic fiber (unstretched polyester fiber, fiber diameter 10.5 μm, Fiber length 5mm, melting point 260 ° C), fine fiber (stretched polyester fiber, elongation 45%, tensile strength 0.41N / tex, fiber diameter 8.6μm, fiber length 5mm) 40:30:30 After mixing and dispersing in water at a ratio and forming a wet paper web with an X-face layer with a circular paper machine, the two wet paper sheets are combined, dried with a Yankee dryer with a surface temperature of 130 ° C, and dried with a Y-face layer. A sheet having a basis weight ratio of 1: 1 and X plane layer of 1: 1 and a total basis weight of 80 g / m ² was obtained. In addition, it heat-dried so that X surface might touch a Yankee dryer.

  The obtained sheet was subjected to hot-pressure processing under the conditions of a temperature of 225 ° C., a pressure of 980 N / cm, and a processing speed of 25 m / min using a calender device combining a heated metal roll and an elastic roll (no heating) (first) Hot-press roll nip), and using a calender device that combines a heated metal roll and a heated metal roll, the hot-press process is performed at a temperature of 225 ° C., a pressure of 980 N / cm, and a processing speed of 25 m / min (second hot-press roll nip). ), A semipermeable membrane support was obtained.

(Example 54)
Thick fibers and fine fibers are divided into thick fibers (stretched polyester fibers, 35% elongation, tensile strength 0.45 N / tex, fiber diameter 18.2 μm, fiber length 5 mm), thin fibers (stretched polyester fibers). A semipermeable membrane support was obtained in the same manner as in Example 43 except that the fiber was changed to 35% elongation, tensile strength 0.45 N / tex, fiber diameter 10.5 μm, fiber length 5 mm.

(Example 55)
Thick fibers and fine fibers are made of large fiber (stretched polyester fiber, elongation 100%, tensile strength 0.30 N / tex, fiber diameter 18.2 μm, fiber length 5 mm), thin fiber (stretched polyester fiber). A semipermeable membrane support was obtained in the same manner as in Example 43 except that the fibers were changed to 100% elongation, tensile strength 0.30 N / tex, fiber diameter 10.5 μm, fiber length 5 mm.

(Example 56)
Thick fibers and fine fibers are made of large fiber (stretched polyester fiber, elongation 150%, tensile strength 0.11 N / tex, fiber diameter 18.2 μm, fiber length 5 mm), thin fiber (stretched polyester fiber). A semipermeable membrane support was obtained in the same manner as in Example 43 except that the fiber, elongation rate 150%, tensile strength 0.11 N / tex, fiber diameter 10.5 μm, fiber length 5 mm) were changed.

(Example 57)
Thick fibers and fine fibers are divided into thick fibers (stretched polyester fibers, elongation 25%, tensile strength 0.70 N / tex, fiber diameter 18.2 μm, fiber length 5 mm), thin fibers (stretched polyester fibers). A semipermeable membrane support was obtained in the same manner as in Example 43 except that the fiber, elongation rate 25%, tensile strength 0.70 N / tex, fiber diameter 10.5 μm, fiber length 5 mm) were changed.

(Example 58)
Thick fibers and fine fibers are divided into thick fibers (stretched polyester fibers, elongation 145%, tensile strength 0.23 N / tex, fiber diameter 18.2 μm, fiber length 5 mm), thin fibers (stretched polyester fibers). A semipermeable membrane support was obtained in the same manner as in Example 43 except that the fiber, elongation 145%, tensile strength 0.23 N / tex, fiber diameter 10.5 μm, fiber length 5 mm) were changed.

(Example 59)
Thick fibers and fine fibers are divided into thick fibers (stretched polyester fiber, elongation 60%, tensile strength 0.58 N / tex, fiber diameter 18.2 μm, fiber length 5 mm), thin fibers (stretched polyester fiber). A semipermeable membrane support was obtained in the same manner as in Example 43, except that the fiber was changed to 60% elongation, tensile strength 0.58 N / tex, fiber diameter 10.5 μm, fiber length 5 mm.

(Example 60)
Thick fibers and fine fibers are divided into thick fibers (stretched polyester fibers, elongation 165%, tensile strength 0.08 N / tex, fiber diameter 18.2 μm, fiber length 5 mm), thin fibers (stretched polyester fibers). Fiber, elongation 165%, tensile strength 0.08 N / tex, fiber diameter 10.5 μm, fiber length 5 mm), and the hot pressing speed was changed to 30 m / min. A semipermeable membrane support was obtained.

(Example 61)
A thick fiber and a thin fiber are divided into a thick fiber (stretched polyester fiber, 25% elongation, tensile strength 0.80 N / tex, fiber diameter 18.2 μm, fiber length 5 mm), and thin fiber (stretched polyester fiber). Fiber, elongation rate 25%, tensile strength 0.80 N / tex, fiber diameter 10.5 μm, fiber length 5 mm), and the hot pressing speed was changed to 10 m / min. A semipermeable membrane support was obtained.

(Example 62)
Thick fibers and fine fibers are made of large fiber (stretched polyester fiber, elongation 25%, tensile strength 0.75 N / tex, fiber diameter 18.2 μm, fiber length 5 mm), thin fiber (stretched polyester fiber). Fiber, elongation 25%, tensile strength 0.75 N / tex, fiber diameter 10.5 μm, fiber length 5 mm), except that the hot pressing speed was changed to 20 m / min and the nip pressure was changed to 780 N / cm. A semipermeable membrane support was obtained in the same manner as in Example 43.

(Example 63)
Thick fibers and fine fibers are divided into thick fibers (stretched polyester fibers, elongation 150%, tensile strength 0.25 N / tex, fiber diameter 18.2 μm, fiber length 5 mm), thin fibers (stretched polyester fibers). A semipermeable membrane support was obtained in the same manner as in Example 43 except that the fibers were changed to 150% elongation, tensile strength 0.25 N / tex, fiber diameter 10.5 μm, fiber length 5 mm.

(Example 64)
Thick fibers and fine fibers are divided into thick fibers (stretched polyester fibers, elongation 23%, tensile strength 0.90 N / tex, fiber diameter 18.2 μm, fiber length 5 mm), fine fibers (stretched polyester fibers). Fiber, elongation 23%, tensile strength 0.90 N / tex, fiber diameter 10.5 μm, fiber length 5 mm), and the hot pressing speed was changed to 10 m / min. A semipermeable membrane support was obtained.

(Example 65)
Thick fibers and fine fibers are divided into thick fibers (stretched polyester fibers, elongation rate 170%, tensile strength 0.07 N / tex, fiber diameter 18.2 μm, fiber length 5 mm), thin fibers (stretched polyester fibers). Example 43, except that the fiber, the elongation rate was 170%, the tensile strength was 0.07 N / tex, the fiber diameter was 10.5 μm, and the fiber length was 5 mm, and the hot pressing speed was 30 m / min and the nip pressure was 780 N / cm. A semipermeable membrane support was obtained in the same manner as above.

(Comparative Example 14)
Thick fibers and fine fibers are divided into thick fibers (stretched polyester fibers, elongation 23%, tensile strength 0.90 N / tex, fiber diameter 18.2 μm, fiber length 5 mm), fine fibers (stretched polyester fibers). A semipermeable membrane support was obtained in the same manner as in Example 43 except that the fiber, 23% elongation, tensile strength 0.90 N / tex, fiber diameter 10.5 μm, fiber length 5 mm) were used.

(Comparative Example 15)
Thick fibers and fine fibers are divided into thick fibers (stretched polyester fibers, elongation rate 170%, tensile strength 0.07 N / tex, fiber diameter 18.2 μm, fiber length 5 mm), thin fibers (stretched polyester fibers). Example 43, except that the fiber, the elongation rate was 170%, the tensile strength was 0.07 N / tex, the fiber diameter was 10.5 μm, and the fiber length was 5 mm, and the hot pressing speed was 20 m / min and the nip pressure was 780 N / cm. A semipermeable membrane support was obtained in the same manner as above.

  The semipermeable membrane supports of Examples 43 to 65 have both the penetration of the semipermeable membrane, the semipermeable membrane adhesive property, and the non-coated surface adhesive property regardless of whether the X surface or the X surface is a semipermeable membrane coated surface. It was a level with no problem in practical use. In the semipermeable membrane supporting material of Example 44, since the elongation percentage of the main synthetic fiber was 23%, a paper break rarely occurred during hot pressing. In the semipermeable membrane supports of Examples 47 and 48 in which the elongation rates of the main synthetic fibers were 120% and 140%, a slight width shrinkage was observed during hot pressing, but this was a level that was not a problem for practical use. It was. The semipermeable membrane support of Example 51 having a two-layer structure and different X-plane and Y-plane fiber blends has a semipermeable membrane soaking and non-coated surface adhesiveness when the X-plane is a semipermeable membrane-coated surface. The semipermeable membrane adhesion was excellent when the Y surface was a semipermeable membrane coated surface.

  In the semi-permeable membrane supports of Examples 52 and 53 in which the two-layer structure, the X-plane and Y-plane fiber blends are different, and the hot-pressing roll nip process was performed twice in the hot-pressing process, the X-plane is the semi-permeable membrane. The non-application surface adhesiveness when the coated surface was used and the semipermeable membrane adhesive property when the Y surface was the semipermeable membrane coated surface were excellent.

  The semipermeable membrane supports of Examples 56, 58 and 63 in which the elongation percentages of the main synthetic fibers were 150% and 145% were observed to have a width shrinkage during hot pressing, but were at a practical limit level. .

  In the semipermeable membrane supports of Examples 61 and 62, the elongation percentage of the main synthetic fiber was 25%, and therefore, rarely a paper break occurred during hot pressing. In the semipermeable membrane support of Example 64, the elongation percentage of the main synthetic fiber is 23%, and the tensile strength of the main synthetic fiber is 0.90 N / tex. Although it occurred, it was a practical limit level. In the semipermeable membrane support of Example 65 in which the elongation percentage of the main synthetic fiber was 170%, width shrinkage was observed during the hot pressing. Moreover, the heating dimensional change rate was −0.5%, which was a level with a slight problem in practical use.

  In the semipermeable membrane support of Comparative Example 14, the cross-sectional aspect ratio of the main synthetic fiber on the X plane and the cross-sectional aspect ratio of the main synthetic fiber on the Y plane were 1.1, and the average breaking length (at 5% elongation) was It was as high as 4.0 km or more, and the tensile strength of the fiber was as high as 0.90 N / tex. During hot pressing, a paper break occurred at the exit of the heating roll, which was not suitable for practical use. The semipermeable membrane support of Comparative Example 15 has a cross-sectional aspect ratio of the X-side main synthetic fiber and a Y-side main synthetic fiber of 3.3 and 3.2, and has a width during hot pressing. Shrinkage was great. Moreover, the wrinkle at the time of semi-permeable membrane application was severe, and it was not suitable for practical use.

  The semipermeable membrane support of the present invention can be used in fields such as seawater desalination, water purifiers, food concentration, wastewater treatment, medical filtration typified by blood filtration, and ultrapure water production for semiconductor cleaning. it can.

Claims (11)

In the method for producing a semipermeable membrane support,
The semipermeable membrane support comprises at least two or more main synthetic fibers and binder synthetic fibers having different fiber diameters, and comprises a wet papermaking nonwoven fabric having a semipermeable membrane application surface and a semipermeable membrane non-application surface, The cross-sectional aspect ratio (fiber cross-section major axis / fiber cross-section minor axis) of the main synthetic fiber existing from the surface of the semipermeable membrane application surface to 1/3 in the thickness direction observed by the cross-sectional SEM and the semipermeable membrane non-application surface The cross-sectional aspect ratio (fiber cross-section major axis / fiber cross-section minor axis) of the main synthetic fiber existing from the surface to 1/3 is 1.2 to 3.0,
A single-layer wet paper manufactured by one type of paper machine selected from the group of long paper machines, circular paper machines, and inclined wire type paper machines, or a combination of the same or different types of paper machines selected from this group A wet paper with a multilayer structure manufactured by a combination paper machine is hot-pressure dried to produce a sheet, and then hot-pressed .
The surface temperature of the hot roll in hot pressure drying is 100 to 180 ° C., the pressure is 50 to 1000 N / cm,
The semipermeable membrane support, wherein the surface temperature of the hot roll in hot pressing is 150 to 260 ° C., the nip pressure of the roll is 190 to 1800 N / cm, and the processing speed is 3 to 100 m / min. Manufacturing method . 2. The semipermeable membrane according to claim 1, wherein the cross-sectional aspect ratio (fiber cross-section major axis / fiber cross-section minor axis) of the main synthetic fiber existing from the surface of the semipermeable membrane application surface to 1/3 is 1.3 to 3.0. A method for producing a support. 2. The semipermeable membrane according to claim 1, wherein the cross-sectional aspect ratio (fiber cross-section major axis / fiber cross-section minor axis) of the main synthetic fiber existing from the surface of the semipermeable membrane application surface to 1/3 is 1.4 to 3.0. A method for producing a support. 2. The semipermeable membrane according to claim 1, wherein the cross-sectional aspect ratio (fiber cross-section major axis / fiber cross-section minor axis) of the main synthetic fiber existing from the surface of the semi-permeable membrane non-coated surface to 1/3 is 1.2 to 2.7. A method for producing a membrane support. 2. The semipermeable membrane according to claim 1, wherein the cross-sectional aspect ratio (fiber cross-section major axis / fiber cross-section minor axis) of the main synthetic fiber existing from the surface of the semi-permeable membrane non-coated surface to 1/3 is 1.2 to 2.5. A method for producing a membrane support. The method for producing a semipermeable membrane supporting material according to any one of claims 1 to 5, wherein the binder synthetic fiber is an unstretched synthetic fiber. The method for producing a semipermeable membrane support according to any one of claims 1 to 6, wherein the content of the binder synthetic fiber relative to the total mass of the main synthetic fiber and the binder synthetic fiber is more than 20 mass% and 40 mass% or less. The method for producing a semipermeable membrane support according to any one of claims 1 to 6, wherein the content of the binder synthetic fiber relative to the total mass of the main synthetic fiber and the binder synthetic fiber is 25% by mass or more and 35% by mass or less. The average value of the longitudinal (MD) and transverse (CD) tear lengths at 5% elongation of the nonwoven fabric is less than 4.0 km, and the transverse dimension (CD) heating dimensional change rate of the nonwoven fabric is −0. The method for producing a semipermeable membrane support according to any one of claims 1 to 8, wherein the content is 3 to + 1.0%. The elongation percentage of the main synthetic fiber (JIS L1013 2010) is 25 to 150%, and the tensile strength of the main synthetic fiber is 0.08 to 0.8 N / tex . Manufacturing method . The method for producing a semipermeable membrane support according to any one of claims 1 to 10, wherein the nonwoven fabric has a multilayer structure.

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