Partition member for total heat exchange element, total heat exchange element using same, and method for producing partition member for total heat exchange element

Abstract

The present invention provides a partition member for a total heat exchanger which exhibits excellent heat exchange efficiency, and a method for producing the same. The present invention is: a partition member which is to be used in a total heat exchange element, comprises a hydrophobic porous substrate and fine fibers of a polymer polysaccharide having a fiber width of 1-1,000 nm in at least a hole portion of the hydrophobic porous substrate, wherein the air permeability is at least 10,000 seconds or more, and the moisture permeability under conditions of 20°C and 65% RH is at least 2,500 g / m2×24 hours; and a method for producing a partition member for a total heat exchange element which involves coating a hydrophobic porous substrate with a coating solution which contains fine fibers of a polymer polysaccharide having a fiber width of 1-1,000 nm, and drying the coated substrate.

Description

Partition member for total heat exchange element, total heat exchange element using same, and method for manufacturing partition member for total heat exchange element

[0001] The present invention relates to a partition member for a total heat exchange element, a total heat exchange element including the same, and a method for manufacturing a partition member for a total heat exchange element.

[0002] Conventionally, heat exchange ventilation devices (total heat exchangers) that exchange heat between intake air and exhaust air during ventilation have been proposed as devices that can ventilate without impairing the cooling or heating effects. These total heat exchangers are widely used, and are constructed by stacking multiple partition members (liners) via spacing members to separate an intake air path that introduces outdoor air into the room and an exhaust air path that exhausts indoor air to the outside, and incorporating a total heat exchange element that simultaneously exchanges sensible heat (temperature) and latent heat (humidity).

[0003] For example, in winter, outdoor air as supply air and indoor air as exhaust air are guided into each flow path separated by a spacing member. In this case, the supply air and the exhaust air exchange temperature and humidity through a partition member. The partition member through which heat exchange occurs has moisture permeability, allowing water vapor to pass through but not air. The partition member also has gas barrier properties by isolating the supply air and the exhaust air. As a result, the supply air is heated and humidified before being supplied to the room, while the exhaust air is cooled and dehumidified before being discharged to the outside. The partition member's moisture permeability and gas barrier properties enable ventilation through total heat exchange. Because such partition members must have both heat conductivity and moisture permeability, paper primarily composed of natural pulp, such as glassine paper, is often used (Patent Document 1).

[0004] In recent years, attempts have also been made to apply cellulose nanofibers, which have gas barrier properties, to partition members (Patent Document 2).

[0005] Patent No. 4252892 JP 2021-155865

[0006] In the face of growing demands for global warming and energy conservation, total heat exchange elements are attracting attention. However, in order to further improve the heat exchange efficiency of total heat exchange elements, it is thought that it would be effective to make the partition members thinner than ever before and to increase the number of stacked layers of the total heat exchange element. However, this has been difficult to achieve with the partition members described in Patent Documents 1 and 2.

[0007] The present inventors conducted extensive research to provide a partition member for a total heat exchanger with excellent heat exchange efficiency, and as a result, discovered a new partition member using a hydrophobic porous substrate and a hydrophilic material, which led to the invention. That is, the present invention relates to the following <1> to <15>. <1> A partition member for a total heat exchange element comprising a hydrophobic porous substrate and a hydrophilic material, which has an air permeability of 10,000 seconds or more and a moisture permeability of 2,500 g / m2 under conditions of 20°C and 65% RH. ２ <2> A partition member for a total heat exchange element, the partition member having a durability of 24 hours or more. <2> A partition member for a total heat exchange element, the partition member comprising: a hydrophobic porous substrate; and fine fibers of a polymeric polysaccharide having a fiber width of 1 to 1000 nm in at least the pores of the hydrophobic porous substrate; and an air permeability of 10000 seconds or more and a moisture permeability of 2500 g / m2 or more under conditions of 20°C and 65% RH. ２ - A partition member for a total heat exchange element having a durability of 24 hours or more. <3> A partition member for a total heat exchange element according to <2>, wherein the fine fibers are fine cellulose fibers. <4> A partition member for a total heat exchange element according to <2> or <3>, wherein the air permeability of the hydrophobic porous substrate is 1000 seconds or less. <5> A partition member for a total heat exchange element according to any one of <2> to <4>, wherein the thickness of the hydrophobic porous substrate is 5 μm or more and 30 μm or less. <6> A partition member for a total heat exchange element according to any one of <2> to <5>, wherein the fine fibers are attached to the hydrophobic porous substrate. <7> A partition member for a total heat exchange element comprising a hydrophobic porous substrate and a hydrophilic material, wherein the hydrophilic material is attached to the hydrophobic porous substrate, wherein the thickness of the hydrophobic porous substrate is 5 μm or more and 30 μm or less, and wherein the amount of attached hydrophilic material is 0.01 g / m ２ 8g / m or more ２ The surface density of the partition member for a total heat exchange element is 30 g / m or less. ２A partition member for a total heat exchange element having an air permeability of 10,000 seconds or more as described below. <8> A total heat exchange element comprising a plurality of partition members for a total heat exchange element according to any one of <1> to <7>, and spacing members arranged between the plurality of partition members for a total heat exchange element to maintain a gap between adjacent partition members for a total heat exchange element, the total heat exchange element having a first air flow path formed by the partition members for a total heat exchange element and the spacing members provided thereon, and a second air flow path formed by the partition members for a total heat exchange element that form the first air flow path and the spacing members provided thereunder. <9> A method for producing a partition member for a total heat exchange element, comprising applying a coating liquid containing fine fibers of a high molecular weight polysaccharide having a fiber width of 1 to 1,000 nm to a hydrophobic porous substrate, followed by drying. <10> A method for producing a partition member for a total heat exchange element according to <9>, wherein the coating liquid contains a surfactant. <11> A total heat exchange element having a coating amount of the fine fibers of 0.01 g / m ２ 8g / m or more ２ <12> The method for manufacturing a partition member for a total heat exchange element according to any one of <9> to <11>, wherein the fine fibers are fine cellulose fibers. <13> The method for manufacturing a partition member for a total heat exchange element according to any one of <9> to <12>, wherein the hydrophobic porous substrate has an air permeability of 1000 seconds or less. <14> The method for manufacturing a partition member for a total heat exchange element according to any one of <9> to <13>, wherein the hydrophobic porous substrate is subjected to a surface hydrophilization treatment and then the coating liquid is applied. <15> A method for manufacturing a partition member for a total heat exchange element according to any one of <9> to <13>, wherein the hydrophobic porous substrate has a thickness of 5 μm or more and 30 μm or less, and wherein the amount of hydrophilic material attached is 0.01 g / m ２ 8g / m or more ２ The coating liquid containing the hydrophilic material is applied and dried so that the surface density is 30 g / m or less. ２ The following describes a method for manufacturing a partition member for a total heat exchange element having an air permeability of 10,000 seconds or more.

[0008] The present invention provides a partition member for a total heat exchange element having excellent heat exchange efficiency, a total heat exchange element using the same, and a method for manufacturing a partition member for a total heat exchange element. It also provides a lightweight, extremely thin partition member for a total heat exchange element having high heat exchange efficiency, a total heat exchange element using the same, and a method for manufacturing a partition member for a total heat exchange element.

[0009] FIG. 1 is a schematic diagram illustrating the structure of a total heat exchange element.

[0010] The partition member for a total heat exchange element will be described below. [Partition member for a total heat exchange element] First embodiment The partition member for a total heat exchange element of this embodiment (hereinafter also referred to as a partition member) is a partition member for a total heat exchange element that includes a hydrophobic porous substrate (hereinafter also referred to as a substrate) and a hydrophilic material, and has an air permeability of 10,000 seconds or more and a moisture permeability of 2,500 g / m under conditions of 20°C and 65% RH. ２ ・24 hours or more.

[0011] "Air permeability" is a value measured in accordance with the Oken air permeability method of JAPAN TAPPI Paper and Pulp Testing Method No. 5-2:2000. A preferred air permeability is 40,000 seconds or more. A higher air permeability value indicates better gas barrier properties. The air permeability of the partition member for a heat exchange element of this embodiment is 10,000 seconds or more. A preferred air permeability is 40,000 seconds or more.

[0012] "Moisture permeability" is a value measured in accordance with JIS Z 0208:1976. The preferred moisture permeability is 3000 g / m ２ - 24 hours or more. A higher moisture permeability value means better heat exchange efficiency.

[0013] (Hydrophobic porous substrate) The substrate to be used is not particularly limited, but a thickness of 5 μm or more and 30 μm or less is preferable, and 10 to 25 μm is more preferable. By setting the thickness at or above the lower limit, the strength as a partition member is maintained, and by setting it at or below the upper limit, the heat exchange efficiency of sensible heat (temperature) is improved and weight reduction is possible. The thickness is a value measured in accordance with JIS P 8118:2014.

[0014] The surface density of the substrate is 29 g / m ２ Preferably, it is 25 g / m or less. ２ More preferably, it is 20 g / m or less. ２ The lower limit is not particularly limited, and is 2 g / m or less. ２ More preferably, 5 g / m２ By setting the surface density of the substrate to the upper limit or less, sufficient pores and voids are secured to ensure the necessary moisture permeability, and by setting the surface density to the lower limit or more, the strength required as a partition member is maintained. The surface density of the hydrophobic porous substrate is a value measured by the weight per unit area.

[0015] The substrate is hydrophobic, which allows for weight reduction. For example, if hydrophilic paper is used, a large amount of fine fibers of polymeric polysaccharides must be applied to enhance gas barrier properties, making it difficult to reduce the weight.

[0016] The air permeability of the substrate is preferably 1000 seconds or less, more preferably 500 seconds or less. If the substrate is porous with an air permeability of 1000 seconds or less, heat exchange of latent heat (humidity) is carried out smoothly. The lower limit of the air permeability is not particularly limited, but is 10 seconds or more, preferably 30 seconds or more, and more preferably 50 seconds or more. For example, films or nonwoven fabrics made of thermoplastic resins such as polyolefins and polyesters, which have an air permeability of 1000 seconds or less, preferably 500 seconds or less, can be used.

[0017] By attaching a hydrophilic material to the substrate, it is possible to increase the air permeability and improve the gas barrier properties of the partition member without significantly impairing the moisture permeability. ２ 8g / m or more ２ When the amount of the hydrophilic material is less than 5 g / m, the pores of the substrate can be blocked with the hydrophilic material, and the decrease in moisture permeability can be suppressed. When the amount of the hydrophilic material attached is large, the gas barrier property is excellent, but the moisture permeability tends to be impaired. ２ On the other hand, if the amount of hydrophilic material attached is small, sufficient gas barrier properties tend not to be obtained, and the amount of attachment is preferably 0.03 g / m or less. ２ The amount of the hydrophilic material to be attached can be rephrased as the amount of the hydrophilic material to be applied, as will be described in detail below.

[0018] (Hydrophilic Material) The hydrophilic material is not particularly limited as long as it forms a film by adhering to a substrate and exhibits gas barrier properties. Examples include polymeric polysaccharides such as cellulose, chitin, chitosan, and carboxymethyl cellulose, and their derivatives; polyvinyl alcohol and its derivatives; and ethylene-vinyl alcohol copolymers and their derivatives. For example, polymeric polysaccharides have a molecular structure with many hydroxyl groups (—OH), and therefore have moisture absorption properties, and the film they form has gas barrier properties. Polyvinyl alcohol also has a molecular structure with many hydroxyl groups (—OH groups), and also has excellent film properties. Among these, fibrous materials are preferred, with fine fibers of polymeric polysaccharides being more preferred, and fine cellulose fibers being particularly preferred. Fine cellulose fibers are preferred because they form a dense structure when attached by coating and drying, and therefore have excellent gas barrier properties.

[0019] Second Embodiment The partition member of this embodiment contains a hydrophobic porous substrate and fine fibers of a polymeric polysaccharide having a fiber width of 1 to 1000 nm in at least the pore portions of the hydrophobic porous substrate, and has an air permeability of 10000 seconds or more and a moisture permeability of 2500 g / m ２ - 24 hours or more. In order to enhance the gas barrier property, the partition member for a total heat exchange element of this embodiment must contain fine fibers of high molecular weight polysaccharides having a fiber width of 1 to 1000 nm in at least the pore portions of the hydrophobic porous substrate, and must have an air permeability of 10,000 seconds or more. A preferred air permeability is 40,000 seconds or more. The air permeability of the partition member can be measured using the same measurement method as that described for the partition member of the first embodiment above.

[0020] Furthermore, the partition member for a total heat exchange element of this embodiment has a moisture permeability of 2500 g / m at a temperature of 20°C and a relative humidity of 65%. ２ It must be 24 hours or more. A higher moisture permeability value indicates better heat exchange efficiency. The preferred moisture permeability is 2800 g / m ２ 24 hours or more, more preferably moisture permeability is 3000 g / m ２The moisture permeability of the partition member can be measured by the same method as that described for the partition member of the first embodiment.

[0021] (Hydrophobic Porous Substrate) As the hydrophobic porous substrate of the partition member of this embodiment, a substrate similar to the substrate used in the first embodiment can be used.

[0022] (Polymer polysaccharide fine fibers) In the partition member of this embodiment, polymer polysaccharide fine fibers having a fiber width of 1 to 1000 nm are attached to at least the pores of the hydrophobic porous substrate so as to satisfy both the above-mentioned physical properties of air permeability and moisture permeability. The amount of polymer polysaccharide fine fibers attached to the hydrophobic porous substrate is not particularly limited, but it is preferably 0.01 g / m ２ 8g / m or more ２ About 0.03 g / m or less, preferably 0.03 g / m ２ 3g / m or more ２ More preferably, 0.03 g / m or less ２ 2g / m or more ２ By attaching the hydrophilic material, the pores of the substrate can be blocked with the hydrophilic material, and the decrease in moisture permeability can be suppressed. When the amount of attached fine fibers of polymeric polysaccharides is large, the gas barrier property is excellent, but the moisture permeability tends to be impaired. ２ On the other hand, if the amount of attached fine fibers of high molecular weight polysaccharide is small, the pores are not sufficiently covered and sufficient gas barrier properties tend not to be obtained. ２ It is preferable that this is equal to or greater than this.

[0023] The fine fibers of polymeric polysaccharides are not particularly limited as long as they are water-insoluble materials that adhere to a hydrophobic porous substrate to form a film and exhibit gas barrier properties. Examples include polymeric polysaccharides such as cellulose, chitin, and chitosan. Polymeric polysaccharides have a molecular structure with many hydroxyl groups (—OH), which allows them to absorb moisture, and the film they form has gas barrier properties. Among these, the use of fine fibers with a fiber width of 1 to 1,000 nm can increase air permeability and moisture permeability. From the viewpoint of gas barrier properties, a fiber width of 1 to 500 nm is preferred, and a fiber width of 1 to 100 nm is more preferred. Fine cellulose fibers are particularly preferred because they form a dense structure when attached by coating and drying, resulting in excellent gas barrier properties.

[0024] As the fine fibers of polymeric polysaccharides, it is preferable to use fine cellulose fibers having a fiber width of 1 to 1,000 nm. Among these, from the viewpoint of gas barrier properties, a fiber width of 1 to 500 nm is preferred, a fiber width of 1 to 100 nm is more preferred, a fiber width of 1 to 10 nm is even more preferred, and a fiber width of 1 to 10 nm is particularly preferred. By making the fiber width of the fine cellulose fibers 1 nm or more, dissolution of the cellulose molecules in water is suppressed, and the effect of improving air permeability and moisture permeability by the fine cellulose fibers is easily achieved.

[0025] The fiber width of polymer polysaccharide fine fibers is measured using an electron microscope as follows. First, an aqueous suspension of cellulose fibers with a concentration of 0.05% by mass to 0.1% by mass is prepared, and this suspension is cast onto a hydrophilically treated carbon film-coated grid to prepare a sample for TEM observation. When wide fibers are included, an SEM image of the surface cast onto glass may be observed. Next, electron microscope images are observed at magnifications of 1,000x, 5,000x, 10,000x, or 50,000x, depending on the width of the fibers to be observed. However, the sample, observation conditions, and magnification are adjusted to satisfy the following conditions: (1) A line X is drawn at any location within the observed image, and 20 or more fibers intersect with this line X. (2) A line Y is drawn within the same image, intersecting the line X perpendicularly, and 20 or more fibers intersect with this line Y. For observed images that satisfy the above conditions, the widths of the fibers intersecting with line X and line Y are visually determined. In this way, three or more sets of observation images of at least non-overlapping surface portions are obtained. Next, for each image, the widths of the fibers intersecting with line X and line Y are read. This results in readings of at least 20 fibers x 2 x 3 = 120 fiber widths. The average fiber width is the average value of the fiber widths of the fine fibers of the high molecular weight polysaccharide that were read.

[0026] The fiber length of the polymer polysaccharide fine fibers is not particularly limited, but is preferably 0.1 μm or more, and preferably 1,000 μm or less, more preferably 800 μm or less, and even more preferably 600 μm or less. By setting the fiber length of the polymer polysaccharide fine fibers within the above range, destruction of the crystalline regions of the polymer polysaccharide fine fibers can be suppressed. In addition, it is possible to set the slurry viscosity of the microfibrillated cellulose fibers within an appropriate range, making it easier to form a fiber layer. The fiber length of the microfibrillated cellulose fibers can be determined, for example, by image analysis using TEM, SEM, or AFM.

[0027] The axial ratio (fiber length / fiber width) of the fine fibers of the polymeric polysaccharide is not particularly limited, but is preferably at least 20, more preferably at least 50, and is preferably at most 10,000, more preferably at most 1,000. By setting the axial ratio within the above range, a slurry viscosity suitable for forming a fiber layer can be obtained.

[0028] In the partition member of this embodiment, it is preferable that at least one type of group selected from ionic groups and nonionic groups be introduced into the polymer polysaccharide fine fibers. Furthermore, it is preferable that the ionic groups and nonionic groups be hydrophilic groups. From the viewpoint of improving the dispersibility of the fibers in the dispersion medium and increasing the defibration efficiency in the defibration treatment, it is more preferable that the polymer polysaccharide fine fibers have ionic groups. The ionic groups may include either or both of anionic groups and cationic groups. In this embodiment, it is particularly preferable that the ionic groups include anionic groups. The anionic groups are preferably at least one type selected from a phosphate group or a group derived from a phosphate group, a phosphite group or a group derived from a phosphite group, a carboxy group or a group derived from a carboxy group, and a sulfonic acid group or a group derived from a sulfonic acid group.

[0029] The partition member for a total heat exchange element of this embodiment comprises a hydrophobic porous substrate and fine fibers of a polymeric polysaccharide having a fiber width of 1 to 1000 nm in at least the pores of the hydrophobic porous substrate, and has an air permeability of 10000 seconds or more and a moisture permeability of 2500 g / m ２ The partition member of this embodiment is a partition member for a total heat exchanger that has high air permeability and moisture permeability, and has excellent carbon dioxide barrier properties, and is resistant to deterioration in mechanical strength even when condensation occurs. In addition, because it is lightweight, it is possible to increase the number of stacked total heat exchange elements.

[0030] Third Embodiment The partition member of this embodiment is a partition member for a total heat exchange element, which comprises a hydrophobic porous substrate and a hydrophilic material, and the thickness of the hydrophobic porous substrate is 5 μm or more and 30 μm or less, and the adhesion amount of the hydrophilic material is 0.01 g / m ２ 8g / m or more ２ and the surface density as a partition member for a total heat exchange element is 30 g / m or less.２ The air permeability is 10,000 seconds or more.

[0031] The surface density of the partition member is 30 g / m ２ Preferably, the weight is 26 g / m or less. ２ The lower limit is not particularly limited, and is preferably 2 g / m or less. ２ More preferably, 5 g / m ２ By setting the surface density of the partition member to the upper limit or less, sufficient pores and voids are secured to ensure the necessary moisture permeability, and by setting the surface density to the lower limit or more, the strength of the partition member is maintained. Note that the surface density of the partition member is a value measured using the same measurement method as the method for measuring the surface density of the hydrophobic porous substrate described in the first embodiment above.

[0032] The "air permeability" of the partition member is a value measured by the same method as the method for measuring air permeability described in the first embodiment above. A preferred air permeability is 40,000 seconds or more. A larger air permeability value means better gas barrier properties.

[0033] (Hydrophobic porous substrate) The substrate to be used is not particularly limited as long as it has a thickness of 5 μm or more and 30 μm or less. A preferred thickness is 10 to 25 μm. By setting the thickness at or above the lower limit, the strength as a partition member is maintained, and by setting the thickness at or below the upper limit, the heat exchange efficiency of sensible heat (temperature) is improved and weight reduction is possible. The thickness of the substrate can be measured using the same measurement method as described for the partition member of the first embodiment above.

[0034] The surface density of the partition member for the total heat exchange element is 30 g / m ２ The areal density of the hydrophobic porous substrate is 29 g / m ２ Preferably, it is 25 g / m or less. ２ More preferably, it is 20 g / m or less. ２ The lower limit is not particularly limited, and is 2 g / m or less. ２ More preferably, 5 g / m ２ That's all.

[0035] The thickness of the hydrophobic porous substrate is 5 μm or more and 30 μm or less, and the amount of the hydrophilic material attached is 0.01 g / m ２ 8g / m or more ２ and the surface density as a partition member for a total heat exchange element is 30 g / m or less. ２ By adopting a configuration in which the air permeability is 10,000 seconds or more, an extremely thin partition member for a total heat exchanger having high air permeability and moisture permeability, excellent carbon dioxide barrier properties, and light weight allows for an increase in the number of stacked layers of total heat exchange elements.

[0036] (Hydrophilic Material) In the partition member of this embodiment, the same hydrophilic material as that used in the first and second embodiments can be used.

[0037] (Moisture absorbent) Because the partition member of the present invention has a small amount of attached hydrophilic material (e.g., fine fibers of polymeric polysaccharides), heat exchange of latent heat (humidity) occurs even without the attachment of a moisture absorbent. However, a moisture absorbent may be blended to further increase moisture permeability. Examples of moisture absorbents include inorganic acid salts, organic acid salts, polyhydric alcohols, and ureas. For example, inorganic acid salts include lithium chloride, calcium chloride, and magnesium chloride. Examples of organic acid salts include sodium lactate, calcium lactate, and sodium pyrrolidone carboxylate. Examples of polyhydric alcohols include glycerin, ethylene glycol, triethylene glycol, and polyglycerin. Examples of ureas include urea and hydroxyethyl urea.

[0038] The method for manufacturing a partition member will be described below. [Method for manufacturing a partition member] First embodiment In the method for manufacturing a partition member for a total heat exchange element of this embodiment, a coating liquid containing fine fibers of a high molecular weight polysaccharide having a fiber width of 1 to 1000 nm is applied to at least one surface of a hydrophobic porous substrate, followed by drying.

[0039] Details of the hydrophobic porous substrate and the polymer polysaccharide fine fibers are as described above. The polymer polysaccharide fine fibers are attached by coating. For example, they can be attached by applying a coating liquid containing polymer polysaccharide fine fibers to the hydrophobic porous substrate and drying. Known coating machines can be used for the coating method, and are not particularly limited. Blade coaters, bar coaters, curtain coaters, die coaters, air knife coaters, roll coaters, etc. can be used. Blade coaters and bar coaters are preferred because the pressing force of the blade or bar during coating allows the coating liquid to penetrate into the pores of the porous substrate. For drying, a dryer attached to the coating machine can be used. The drying temperature is preferably a surface temperature of 90°C or less, more preferably 80°C or less. Drying at high temperatures may cause bumping of the coating liquid.

[0040] The amount of fine fibers of high molecular weight polysaccharide attached is 0.01 g / m ２ 8g / m or more ２ When the amount of polymeric polysaccharide fine fibers attached is within the above range, a uniform coating film can be formed, the pores of the substrate can be blocked with the hydrophilic material, and a decrease in moisture permeability can be suppressed. When the amount of polymeric polysaccharide fine fibers attached is large, the gas barrier property is excellent, but the moisture permeability tends to be impaired. ２ On the other hand, if the amount of attached fine fibers of high molecular weight polysaccharides is small, sufficient gas barrier properties tend not to be obtained, and the amount of attached fine fibers is preferably 0.03 g / m or less. ２ The provision of fine fibers of polymeric polysaccharides by coating is preferable because it increases the moisture permeability, possibly because the fine fibers of polymeric polysaccharides penetrate not only the surface of the hydrophobic porous substrate but also the interior of the pores.

[0041] As described above, since a coating liquid containing a hydrophilic material is applied to a hydrophobic porous substrate, the hydrophilic material contained in the coating liquid adheres to the hydrophobic porous substrate. Therefore, the coating amount of the hydrophilic material contained in the coating liquid can be rephrased as the adhered amount of the hydrophilic material.

[0042] When applying a coating liquid containing fine fibers of polymeric polysaccharides to a hydrophobic porous substrate, if the substrate repels the coating liquid, it is recommended to add a surfactant, wetting agent, leveling agent, etc. to the coating liquid, or to subject the substrate to a surface hydrophilization treatment such as corona discharge treatment in advance, or to use a combination of these. If repelling occurs during coating, it tends to be difficult to obtain a partition member for a total heat exchange element with an air permeability of 10,000 seconds or more. It is preferable to use surfactants, wetting agents, leveling agents, etc. that have reduced foaming properties.

[0043] Furthermore, the coating liquid may contain auxiliary agents such as preservatives, mildew inhibitors, flame retardants, viscosity adjusters, pH adjusters, colorants, storage improvers, and polymer resins, as long as the effects of the present invention are not impaired.

[0044] When applying the coating liquid containing the fine fibers of the polymeric polysaccharide, the amount of the coating liquid to be applied is adjusted so that the air permeability of the resulting partition member for a total heat exchange element is 10,000 seconds or more. ２ It is preferable to adjust the deposition amount so that it lasts for 24 hours or more.

[0045] Second Embodiment In the method for manufacturing a partition member for a total heat exchange element of this embodiment, a hydrophilic material is attached in an amount of 0.01 g / m to at least one surface of a hydrophobic porous substrate having a thickness of 5 μm or more and 30 μm or less. ２ 8g / m or more ２ The coating solution containing the hydrophilic material was applied and dried to a surface density of 30 g / m ２ Hereinafter, a partition member for a total heat exchange element having an air permeability of 10,000 seconds or more will be produced.

[0046] Details of the hydrophobic porous substrate and the fine fibers of polymeric polysaccharides are as described above.

[0047] The amount of fine fibers of high molecular weight polysaccharide attached is 0.01 g / m ２ 8g / m or more ２By setting the amount of the polymer polysaccharide fine fibers to 3 g / m or less, a uniform coating film can be formed as described above, the pores of the substrate can be blocked with the hydrophilic material, and a decrease in moisture permeability can be suppressed. When the amount of the polymer polysaccharide fine fibers attached is large, the gas barrier property is excellent, but the moisture permeability tends to be impaired. ２ On the other hand, if the amount of attached fine fibers of high molecular weight polysaccharides is small, sufficient gas barrier properties tend not to be obtained, and the amount of attached fine fibers is preferably 0.03 g / m or less. ２ The provision of fine fibers of polymeric polysaccharides by coating is preferable because it increases the moisture permeability, possibly because the fine fibers of polymeric polysaccharides penetrate not only the surface of the hydrophobic porous substrate but also the interior of the pores.

[0048] The amount of fine fibers of high molecular weight polysaccharide attached is 0.01 g / m ２ 8g / m or more ２ By setting the surface density to 30 g / m or less, ２ Hereinafter, a partition member for a total heat exchange element having an air permeability of 10,000 seconds or more can be easily obtained.

[0049] The total heat exchange element will be described below. [Total heat exchange element] The total heat exchange element of this embodiment is a total heat exchange element using the heat exchange element partition member of the present invention. That is, the total heat exchange element includes a plurality of the total heat exchange element partition members and spacing members arranged between the total heat exchange element partition members to maintain the spacing between adjacent total heat exchange element partition members, and has a first air flow path formed by the total heat exchange element partition members and the spacing members provided thereon, and a second air flow path formed by the total heat exchange element partition members that form the first air flow path and the spacing members provided below them.

[0050] The total heat exchange element will be described below using FIG. 1 , but the present invention is not limited to the total heat exchange element with the structure shown in FIG. 1 . FIG. 1 is a schematic diagram illustrating the structure of a total heat exchange element 10. As shown in FIG. 1 , the total heat exchange element 10 is composed of a plurality of partition members 1 and a plurality of spacing members 2 that form air flow paths between the plurality of partition members 1 and maintain the spacing between the partition members 1. The partition members 1 are flat plates with shapes such as squares or diamonds, and the spacing members 2 maintain the spacing between the partition members 1 and are, for example, corrugated plates with waveforms such as sawtooth waves or sinusoidal waves whose projected planar shape matches the shape of the partition members 1. The spacing members 2 are, for example, shaped like the core of cardboard and are formed by corrugating.

[0051] [Spacing member] The spacing member is not particularly limited as long as it maintains the spacing between the partition members. The spacing member maintains the spacing between the partition members, thereby forming air flow paths between the multiple partition members. The spacing member is not limited to a corrugated material such as a paper substrate, film, or nonwoven fabric, but may also be a resin rib. Among these, a paper substrate is preferred. Because the paper substrate has the function of regulating moisture, it can compensate for the reduced humidity-regulating function of partition members using a hydrophobic porous substrate.

[0052] The ridges and valleys of the waveforms of the spacing members 2 are joined to the partition member 1 with an adhesive or the like. The spacing members 2 are joined to one surface of the partition member 1 with the ridges of the waveforms extending in a first direction (e.g., the vertical direction), and are joined to the other surface of the partition member 1 with the ridges of the waveforms extending in a second direction (e.g., the horizontal direction). In other words, in two adjacent spacing members 2 sandwiching the partition member 1, the spacing members 2 are stacked alternately across the partition member 1 so that the direction of the ridges of the waveforms of the spacing members 2 joined to one surface, i.e., the first air flow path, is perpendicular to the direction of the ridges of the waveforms of the spacing members 2 joined to the other surface, i.e., the second air flow path.

[0053] Between the spacing member 2 whose wavy ridge lines are oriented in a first direction (e.g., the vertical direction) and the partition members 1 on both sides, a plurality of first air flow paths 4 are formed along the first direction. Furthermore, between the spacing member 2 whose wavy ridge lines are oriented in a second direction (e.g., the horizontal direction) and the partition members 1 on both sides, a plurality of second air flow paths 5 are formed along the second direction. Note that arrow 6 in Fig. 1 indicates the direction of air flow in the first air flow path 4, and arrow 7 in Fig. 1 indicates the direction of air flow in the second air flow path 5.

[0054] Spacing members 2 whose corrugated ridgelines are oriented in a first direction and spacing members 2 whose corrugated ridgelines are oriented in a second direction are alternately stacked with the partition member 1 in between so that the ridgelines are perpendicular to each other. Therefore, the first air flow paths 4 and the second air flow paths 5 are also alternately formed so that their extending directions are perpendicular to each other. For example, supply air is ventilated through the first air flow path 4, and exhaust air is ventilated through the second air flow path 5, and heat exchange occurs between the supply air and the exhaust air via the partition member 1 and the spacing members 2. In the example shown in FIG. 1 , the spacing members 2 are arranged so that the first air flow path and the second air flow path are perpendicular to each other. However, the spacing members 2 do not necessarily need to be arranged so that the first air flow path and the second air flow path are perpendicular to each other; they may be oriented in different directions, such as facing each other.

[0055] The method for joining the partition member and the spacing member can be a known method such as a method using an adhesive or a thermal bonding method without using an adhesive. Among these, a method using an adhesive is preferable because it can firmly bond the spacing member and the partition member. Known adhesives such as polyvinyl alcohol adhesives and ethylene vinyl acetate adhesives can be used as the adhesive.

[0056] The features of the present invention will be explained in more detail below with reference to examples and comparative examples. The materials, amounts used, ratios, treatment contents, treatment procedures, etc. shown in the following examples can be changed as appropriate without departing from the spirit of the present invention. Therefore, the scope of the present invention should not be construed as being limited by the specific examples shown below.

[0057] <Preparation of Substrate> Substrate A: A 20 μm thick polyethylene film (product name: SW320H, manufactured by Shenzhen Senior Technology Material Co., Ltd.) was prepared as a hydrophobic porous substrate. The surface density was 10.0 g / m ２ Substrate B: A 16 μm thick polypropylene film (product name: SD216101+, manufactured by Shenzhen Senior Technology Material Co., Ltd.) was prepared as a hydrophobic porous substrate. The surface density was 9.4 g / m ２ It was.

[0058] <Production of Fine Cellulose Fiber A> (Phosphate Group Introduction Step) As a raw material pulp, softwood kraft pulp (solid content 93% by mass, basis weight 210 g / m) manufactured by Oji Paper Co., Ltd. was used. ２ A sheet-like pulp (disintegrated, with a Canadian Standard Freeness (CSF) of 690 ml as measured in accordance with JIS P 8121:2012) was used. This raw pulp was subjected to a phosphating treatment as follows. First, a mixed aqueous solution of ammonium dihydrogen phosphate and urea was added to the raw pulp to adjust the ratio to 45 parts by mass of ammonium dihydrogen phosphate, 120 parts by mass of urea, and 150 parts by mass of water per 100 parts by mass of raw pulp (bone dry mass), thereby obtaining a chemical-impregnated pulp. Next, the obtained chemical-impregnated pulp was heated in a hot air dryer at 165°C for 200 seconds to introduce phosphate groups into the cellulose in the pulp, thereby obtaining a phosphorylated pulp.

[0059] (Washing step) The resulting phosphorylated pulp was then washed. The washing step was carried out by pouring 10 L of ion-exchanged water onto 100 g (bone dry mass) of phosphorylated pulp, stirring to uniformly disperse the pulp, and then repeatedly filtering and dehydrating the pulp. The washing was completed when the electrical conductivity of the filtrate reached 100 μS / cm or less.

[0060] (Alkali Treatment Step) Next, the washed phosphorylated pulp was subjected to an alkali treatment (neutralization treatment) as follows. First, the washed phosphorylated pulp was diluted with 10 L of ion-exchanged water, and then a 1 N aqueous solution of sodium hydroxide was added little by little while stirring to obtain a phosphorylated pulp slurry having a pH of 12 to 13. Next, the phosphorylated pulp slurry was dehydrated to obtain phosphorylated pulp that had been subjected to an alkali treatment (neutralization treatment). Next, the phosphorylated pulp after the alkali treatment was subjected to the above-mentioned washing treatment. The infrared absorption spectrum of the phosphorylated pulp obtained after the alkali treatment was measured using FT-IR. As a result, －１ The phosphorylated pulp was analyzed using an X-ray diffractometer, and typical peaks for cellulose type I crystals were observed at two positions, around 2θ = 14° to 17° and around 2θ = 22° to 23°, confirming the presence of cellulose type I crystals.

[0061] (Defibrillation Treatment Step) Ion-exchanged water was added to the phosphorylated pulp obtained through the alkali treatment step to prepare a slurry with a solids concentration of 2% by mass. This slurry was treated three times at a pressure of 200 MPa using a wet pulverization device (Starburst, manufactured by Sugino Machine Co., Ltd.) to obtain a microfibrillated cellulose fiber dispersion containing microfibrillated cellulose fiber A. X-ray diffraction confirmed that the microfibrillated cellulose fiber A maintained cellulose type I crystals. Furthermore, the fiber width of the microfibrillated cellulose fiber A was measured using a transmission electron microscope and found to be 3 to 5 nm.

[0062] <Production of Microfibrillated Cellulose Fibers B> (Defibrillation Treatment Step) Ion-exchanged water was added to the phosphorylated pulp obtained through the above-mentioned alkali treatment step to prepare a slurry with a solids concentration of 2% by mass. This slurry was treated once with a wet pulverization device (Starburst, manufactured by Sugino Machine Co., Ltd.) at a pressure of 200 MPa to obtain a microfibrillated cellulose fiber dispersion containing microfibrillated cellulose fibers B. X-ray diffraction confirmed that this microfibrillated cellulose fibers B maintained cellulose type I crystals. Furthermore, when the fiber width of microfibrillated cellulose fibers B was measured using a transmission electron microscope, fibers with a fiber width of 3 to 500 nm were confirmed.

[0063] (Example 1-1) <Production of partition member for total heat exchange element> A coating liquid was prepared by adding 0.8 parts of a polyether surfactant (product name: SN Wet 985, manufactured by San Nopco, 76% aqueous dispersion) to 99.2 parts of a 0.4% aqueous dispersion of the fine cellulose fiber A obtained above. One surface of the substrate A was subjected to a corona discharge treatment, and the coating liquid was then applied with a Mayer bar until the adhesion amount (coating amount) of the fine cellulose fiber A after drying was 0.03 g / m. ２ The mixture was coated and dried to obtain a partition member for a total heat exchange element.

[0064] (Example 1-2) In the production of the partition member for the total heat exchange element of Example 1, the adhesion amount (coating amount) of the fine cellulose fibers A after drying was 0.08 g / m ２ A partition member for a total heat exchange element was obtained in the same manner as in Example 1-1, except that the coating and drying were carried out so that the thickness of the coating was 1 / 3 or 1 / 4.

[0065] Comparative Example 1-1 The substrate A was used as it was as a partition member for a total heat exchange element.

[0066] (Comparative Example 1-2) In the production of the partition member for a total heat exchange element in Example 1-1, the adhesion amount (coating amount) of the fine cellulose fibers A after drying was 0.02 g / m ２ A partition member for a total heat exchange element was obtained in the same manner as in Example 1-1, except that the coating and drying were carried out so that the thickness of the coating was 1 / 3 or 1 / 4.

[0067] (Example 1-3) A partition member for a total heat exchange element was obtained in the same manner as in Example 1-1, except that the production of the partition member for a total heat exchange element in Example 1-1 was carried out as follows. <Production of Partition Member for Total Heat Exchange Element> 0.8 parts of a polyether surfactant (product name: SN Wet 985, manufactured by San Nopco, 76% aqueous dispersion) was added to 99.2 parts of a 0.4% aqueous dispersion of the fine cellulose fiber A obtained above to prepare a coating liquid. The coating liquid was applied to one surface of the substrate A using a Mayer bar, and the adhesion amount (coating amount) of the fine cellulose fiber A after drying was 0.17 g / m ２ The mixture was coated and dried to obtain a partition member for a total heat exchange element.

[0068] (Example 1-4) In Example 1-1, the substrate was changed to substrate B. Furthermore, the adhesion amount (coating amount) of the fine cellulose fibers A after drying was 0.09 g / m ２ A partition member for a total heat exchange element was obtained in the same manner as in Example 1-1, except that the coating and drying were carried out so that the thickness of the coating was 1 / 3 or 1 / 4.

[0069] Comparative Example 1-3 The substrate B was used as it was as a partition member for a total heat exchange element.

[0070] Example 1-5 A partition member for a total heat exchange element was obtained in the same manner as in Example 1-1, except that the following was performed.

[0071] <Production of Partition Member for Total Heat Exchange Element> A 0.4% dispersion of the fine cellulose fibers B obtained above was used as a coating liquid. One surface of the substrate A was subjected to a corona discharge treatment, and the coating liquid was then applied with a Mayer bar to a substrate such that the adhesion amount (coating amount) of the fine cellulose fibers B after drying was 0.28 g / m ２ The mixture was coated and dried to obtain a partition member for a total heat exchange element.

[0072] (Example 1-6) In Example 1-5, the adhesion amount (coating amount) of the fine cellulose fibers B after drying was 0.10 g / m ２ A partition member for a total heat exchange element was obtained in the same manner as in Example 1-5, except that the coating and drying were carried out so that the thickness of the coating was 1 / 3 or 1 / 4.

[0073] (Example 1-7) In Example 1-5, the substrate was changed to substrate B. Furthermore, the adhesion amount (coating amount) of the fine cellulose fibers B after drying was 0.28 g / m ２ A partition member for a total heat exchange element was obtained in the same manner as in Example 1-5, except that the coating and drying were carried out so that the thickness of the coating was 1 / 3 or 1 / 4.

[0074] (Evaluation) The moisture permeability and air permeability of the partition members for total heat exchange elements obtained in the Examples and Comparative Examples were measured and are shown in Tables 1 and 2. "Moisture permeability" Measured in accordance with JIS Z0208:1976 under conditions of 20°C and 65% RH. However, it was calculated using the following formula: Moisture permeability = (a + b) / 2, where a = mass increase one hour after the start of measurement, and b = mass increase one hour from one hour after the start of measurement to two hours after the start of measurement.

[0075] "Air permeability" was measured in accordance with the Oken air permeability method of JAPAN TAPPI Paper and Pulp Testing Method No. 5-2:2000.

[0076] "Carbon dioxide gas barrier property" A 12 cm square partition member was prepared, and high concentration CO2 was tested. ２ The measurement device used was a container A for measuring the concentration, a container B that was constantly ventilated with outside air, and a partition member between the containers A and B. Under normal temperature and pressure conditions, CO was placed in the container A. ２ After sealing in 20,000 ppm, the container was left to stand for 15 minutes, and then the CO ２ The concentration of CO ２ The CO passed through the partition member for 15 minutes was measured using an analyzer. ２ The amount of CO permeated in the container A is ２ The CO concentration in container A is calculated as a decrease. ２ When the concentration was 2500 ppm or more, the carbon dioxide gas barrier property of the partition member was judged to be good and marked with ◯, and when it was less than 2500 ppm, it was judged to be poor and marked with X. The evaluation results are shown in Tables 1 and 2 below.

[0077]

[0078]

[0079] (Example 2-1) <Production of Partition Member for Total Heat Exchange Element> 0.8 parts of a polyether surfactant (product name: SN Wet 985, manufactured by San Nopco, 76% aqueous dispersion) was added to 99.2 parts of a 0.4% aqueous dispersion of the fine cellulose fiber A obtained above to prepare a coating liquid. The coating liquid was applied to one surface of the substrate A with a Mayer bar until the adhesion amount of the fine cellulose fiber A after drying was 0.12 g / m. ２ The surface density of the partition member was 10.29 g / m. ２ It was.

[0080] (Example 2-2) In Example 2-1, the substrate was changed to substrate B. Furthermore, the adhesion amount of the fine cellulose fibers A after drying was 0.25 g / m ２ A partition member for a total heat exchange element was obtained in the same manner as in Example 2-1, except that the surface density of the partition member was 9.89 g / m ２ It was.

[0081] Example 2-3 A partition member for a total heat exchange element was obtained in the same manner as in Example 2-1, except that the following was performed.

[0082] <Production of Partition Member for Total Heat Exchange Element> A 0.4% dispersion of the fine cellulose fibers B obtained above was used as a coating liquid. One surface of the substrate A was subjected to a corona discharge treatment, and the coating liquid was then applied with a Mayer bar until the adhesion amount of the fine cellulose fibers B after drying was 0.35 g / m ２ The surface density of the partition member was 10.35 g / m. ２ It was.

[0083] (Comparative Example 2-1) In the production of the partition member for a total heat exchange element in Example 2-1, the adhesion amount of the fine cellulose fibers A after drying was 0.02 g / m ２ A partition member for a total heat exchange element was obtained in the same manner as in Example 2-1, except that the surface density of the partition member was 10.05 g / m ２ It was.

[0084] Comparative Example 2-2 The substrate A was used as it was as a partition member for a total heat exchange element.

[0085] Comparative Example 2-3 The substrate B was used as it was as a partition member for a total heat exchange element.

[0086] (Example 2-4) A partition member for a total heat exchange element was obtained in the same manner as in Example 2-1, except that the following was performed. <Production of Partition Member for Total Heat Exchange Element> A 0.5% aqueous dispersion of the fine cellulose fibers A obtained above was used as a coating liquid. The coating liquid was applied to one side of the substrate A using a bar coater, and the substrate was dried so that the dryer temperature did not exceed 70°C, thereby obtaining a partition member for a total heat exchange element. The adhesion amount of the fine cellulose fibers A was 0.05 g / m ２ The surface density of the partition member was 10.05 g / m ２ It was.

[0087] (Example 2-5) A partition member for a total heat exchange element was obtained in the same manner as in Example 2-1, except that the following was performed in Example 2-1. <Production of Partition Member for Total Heat Exchange Element> 0.4 parts of a polyether surfactant (product name: SN Wet 985, manufactured by San Nopco, 76% aqueous dispersion) was added to 99.6 parts of a 0.5% aqueous dispersion of the fine cellulose fiber A obtained above to prepare a coating liquid. The coating liquid was applied to one side of the substrate A using a bar coater, and the substrate was dried so that the dryer temperature did not exceed 70°C, thereby obtaining a partition member for a total heat exchange element. The adhesion amount of the fine cellulose fiber A was 0.15 g / m ２ The surface density of the partition member was 10.24 g / m ２ It was.

[0088] (Evaluation) The moisture permeability and air permeability of the partition members for total heat exchange elements obtained in the Examples and Comparative Examples were measured and are shown in Tables 3 and 4. Furthermore, for Examples 2-4 and 2-5 and Comparative Examples 2-2 and 2-3, the carbon dioxide barrier property was also evaluated. "Moisture permeability" Measured in accordance with JIS Z0208:1976 under conditions of 20°C x 65% RH. However, it was calculated using the following formula: Moisture permeability = (a + b) / 2, where a = mass increase one hour after the start of measurement, and b = mass increase one hour from one hour after the start of measurement to two hours after the start of measurement.

[0089] "Air permeability" was measured in accordance with the Oken air permeability method of JAPAN TAPPI Paper and Pulp Testing Method No. 5-2:2000.

[0090] <Carbon dioxide barrier property> A carbon dioxide (CO ) barrier was placed inside an acrylic cube-shaped container with 1 m sides and 20 cm square windows in the center of each of the four side faces and one top face. ２ A measuring device was prepared by installing a 25 cm square analyzer. 25 cm square partition members were attached to each window of the measuring device, and 5,000 ppm of carbon dioxide was sealed in the container. ２ The carbon dioxide concentration was measured four times at 15-minute intervals for a total of one hour. The carbon dioxide concentration reduction rate at each time point was calculated from the measured values ​​after 15 minutes, 30 minutes, 45 minutes, and 60 minutes, and the average was calculated to determine the carbon dioxide concentration reduction rate of the measured sample. The lower the carbon dioxide concentration reduction rate, the better the partition member is at preventing carbon dioxide (CO ２ ) It has excellent barrier properties. Note that a material with a carbon dioxide concentration reduction rate of 1.3% or less is preferably used as a partition member.

[0091]

[0092]

[0093] REFERENCE SIGNS LIST 1 Partition member 2 Spacing member 4 First air flow path 5 Second air flow path 10 Total heat exchange element

Claims

1. A partition member for a total heat exchange element comprising a hydrophobic porous substrate and a hydrophilic material, the partition member having an air permeability of 10,000 sec or more and a moisture permeability of 2,500 g / m under conditions of 20°C and 65% RH. ２ A partition member for a total heat exchange element having a life of 24 hours or more.

2. A hydrophobic porous substrate, comprising: fine fibers of polymeric polysaccharides having a fiber width of 1 to 1000 nm at least in the pores of the hydrophobic porous substrate; an air permeability of 10,000 seconds or more; and a moisture permeability of 2,500 g / m2 or more under conditions of 20°C and 65% RH. ２ A partition member for a total heat exchange element having a life of 24 hours or more.

3. A partition member for a total heat exchange element according to claim 2, wherein said fine fibers are fine cellulose fibers.

4. A partition member for a total heat exchange element according to claim 2, wherein the hydrophobic porous substrate has an air permeability of 1000 seconds or less.

5. A partition member for a total heat exchange element according to claim 4, wherein the thickness of said hydrophobic porous substrate is from 5 μm to 30 μm.

6. A partition member for a total heat exchange element according to claim 1, wherein the fine fibers are attached to the hydrophobic porous substrate.

7. A partition member for a total heat exchange element comprising a hydrophobic porous substrate and a hydrophilic material, the hydrophilic material being attached to the hydrophobic porous substrate, the thickness of the hydrophobic porous substrate being 5 μm or more and 30 μm or less, and the amount of the hydrophilic material attached being 0.01 g / m ２ 8g / m or more ２ The surface density of the partition member for a total heat exchange element is 30 g / m or less. ２ The following describes a partition member for a total heat exchange element having an air permeability of 10,000 seconds or more.

8. A total heat exchange element comprising a plurality of partition members for a total heat exchange element according to any one of claims 1 to 7, and having a first air flow path formed by the partition members for a total heat exchange element and the spacing member provided thereon, and a second air flow path formed by the partition members for a total heat exchange element forming the first air flow path and the spacing member provided below them.

9. A method for manufacturing a partition member for a total heat exchange element, comprising applying a coating liquid containing fine fibers of polymeric polysaccharide having a fiber width of 1 to 1,000 nm to a hydrophobic porous substrate, followed by drying.

10. The method for producing a partition member for a total heat exchange element according to claim 9, wherein the coating liquid contains a surfactant.

11. The coating amount of the fine fibers is 0.01 g / m ２ 8g / m or more ２ The method for producing a partition member for a total heat exchange element according to claim 9, wherein the following is performed.

12. The method for producing a partition member for a total heat exchange element according to claim 9, wherein the fine fibers are fine cellulose fibers.

13. The method for producing a partition member for a total heat exchange element according to claim 9, wherein the hydrophobic porous substrate has an air permeability of 1000 seconds or less.

14. The method for producing a partition member for a total heat exchange element according to claim 9, wherein the hydrophobic porous substrate is subjected to a surface hydrophilization treatment, and then the coating liquid is applied thereto.

15. A hydrophobic porous substrate having a thickness of 5 μm or more and 30 μm or less is provided with a hydrophilic material attached in an amount of 0.01 g / m on at least one surface thereof. ２ 8g / m or more ２ The coating liquid containing the hydrophilic material is applied and dried so that the surface density is 30 g / m ２ The following describes a method for producing a partition member for a total heat exchange element having an air permeability of 10,000 seconds or more.

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