Total heat exchange membrane, preparation method thereof and total heat exchanger

Abstract

The invention discloses a total heat exchange membrane, a preparation method thereof and a total heat exchanger. The total heat exchange membrane comprises a porous supporting layer and a functional compact layer coated on the surface of the porous supporting layer. The porous supporting layer comprises modified hydrophobic polymer fibers and a functional agent attached to the surfaces of the modified hydrophobic polymer fibers. After surface modification, a polar oxygen-containing functional group is generated on the surface of the hydrophobic polymer fiber, so that a functional agent can be compounded on the surface of the hydrophobic polymer fiber in forms of electrostatic interaction, hydrogen bonds or covalent bonds and the like. The functional agent is compounded on the surface of the hydrophobic polymer fiber, so that the overall performance of the membrane material can be effectively improved, and excessive filler can be prevented from being additionally introduced into a compact layer, so that the filler can be prevented from blocking or blocking the total heat exchange membrane, and the total heat exchange membrane can maintain excellent heat and humidity performance and total heat exchange capacity.

Description

Technical Field

[0001] The present invention relates to the technical field of heat exchangers, and in particular to a full heat exchange membrane and a preparation method thereof, and a full heat exchanger. Background Art

[0002] As the main heat recovery device in the fresh air system, the full heat exchanger can simultaneously realize the exchange of sensible heat and latent heat compared to the sensible heat exchanger, effectively saving energy while taking into account comfort. The full heat exchange efficiency of the fresh air product depends to a large extent on the heat and mass transfer performance of the full heat exchange core membrane material.

[0003] Existing heat exchange products mostly use paper-based or polymer-based membranes as the heat and moisture exchange medium. Compared to the aluminum membrane media used in sensible heat exchangers, paper-based and polymer-based membranes are hydrophilic (polymer-based membranes have a dense hydrophilic layer), making them susceptible to bacterial and mold growth, significantly impacting the heat exchange core's service life and fresh air quality. Currently, efforts to improve the antibacterial and purification capabilities of heat exchange membranes primarily involve introducing antibacterial fillers into paper pulp solutions or polymer-based coating solutions.

[0004] Polymer-based heat exchange membranes typically have a double-layer asymmetric Janus structure. The dense layer, relying on its hydrophilic properties, effectively dissolves and adsorbs water molecules from moist air, enabling mass transfer. However, the dense layer is relatively thin, accounting for only 2%-10% of the overall membrane material. The porous support layer, which is typically hydrophobic, primarily supports the dense layer, accounting for 90-98% of the overall membrane material by volume.

[0005] Existing methods for improving the antibacterial and other purification functions of polymer-based heat exchange membranes mostly involve introducing high-performance antibacterial fillers into the dense layer formula. However, because the dense layer occupies a relatively small volume of the entire heat exchange membrane, the overall antibacterial performance of the membrane is limited. Furthermore, excessive fillers in the dense layer can clog or block the hygroscopic and thermally conductive fillers, affecting the heat and moisture exchange performance of the dense layer. Furthermore, they can weaken the continuity of the polymer matrix, further compromising the dense layer's airtightness.

[0006] The above information disclosed in this background technology is only used to increase the understanding of the background technology of this application. Therefore, it may contain information that does not constitute the prior art known to ordinary technicians in this field. Summary of the Invention

[0007] In response to the problems pointed out in the background technology, the purpose of the present invention is to provide a full heat exchange membrane and its preparation method, and a full heat exchanger. The full heat exchange membrane has excellent antibacterial properties, thermal and moisture properties and full heat exchange capacity.

[0008] In order to achieve the above-mentioned purpose, the present invention adopts the following technical solutions: The present invention provides a full heat exchange membrane, which includes: a porous support layer and a functional dense layer coated on the surface of the porous support layer; the porous support layer includes modified hydrophobic polymer fibers and a functional agent attached to the surface of the modified hydrophobic polymer fibers; the ratio of the functional agent content to the modified hydrophobic polymer fiber content is X, X is greater than 1%, and X is less than 30%; the porosity of the porous support layer is K, K is greater than 30%, and K is less than 80%; the functional dense layer includes a hydrophilic polymer substrate and a filler.

[0009] In some embodiments of the present application, the surface density of the hydrophobic polymer fiber is N, and N is greater than 5g / m 2 , N less than 40g / m 2 ; The hydrophobic polymer fiber includes at least one of polyethylene fiber, polypropylene fiber and polyester fiber.

[0010] In some embodiments of the present application, the functional agent includes an antibacterial agent, and the antibacterial agent includes one or more of graphene, nanosilver, silver ion compounds, quaternary ammonium salts and titanium dioxide.

[0011] In some embodiments of the present application, the functional agent includes a flame retardant, and the flame retardant includes at least one of an inorganic flame retardant and an organic flame retardant. The inorganic flame retardant includes at least one of aluminum hydroxide, aluminum chloride, magnesium oxide, and a silicon flame retardant. The organic flame retardant includes at least one of ammonium polyphosphate, antimony polyphosphate, ammonium bromide, and chlorinated polyolefin.

[0012] In some embodiments of the present application, the functional agent includes a thermal conductor, and the thermal conductor includes at least one of carbon nanotubes, silver nanowires, graphite, carbon fiber, boron nitride, and aluminum oxide.

[0013] In some embodiments of the present application, the thickness of the functional dense layer is M, M is greater than 0.1 μm, and M is less than 2 μm; the hydrophilic polymer substrate includes one or more of polyvinyl alcohol, polyvinyl pyrrolidone, polyurethane and polyacrylic resin hydrophilic polymers.

[0014] In some embodiments of the present application, the filler includes a hygroscopic filler, and the hygroscopic filler includes one or more of lithium chloride, calcium chloride, sodium chloride, potassium chloride, carboxymethyl cellulose, chitosan and a metal organic framework compound.

[0015] In some embodiments of the present application, the filler includes a porogenic filler, and the porogenic filler includes at least one of polyethylene glycol and silica gel.

[0016] The present invention provides a method for preparing the full heat exchange membrane, which comprises: (1) Preparation of hydrophobic polymer fibers; (2) Surface modification of the hydrophobic polymer fiber to obtain a modified hydrophobic polymer fiber; (3) attaching the functional agent to the surface of the modified hydrophobic polymer fiber to obtain a porous support layer; (4) dissolving the hydrophilic polymer substrate in a solvent, adding fillers, and mixing uniformly by ultrasonication and stirring to obtain a dense layer coating solution; (5) coating the dense layer coating solution on the surface of the porous support layer and drying it to obtain the full heat exchange membrane.

[0017] The present application also provides a total heat exchanger, comprising the total heat exchange membrane.

[0018] Compared with the prior art, the present invention offers the following advantages and positive effects: The present invention provides a total heat exchange membrane, a preparation method thereof, and a total heat exchanger. The total heat exchange membrane comprises a porous support layer and a functional dense layer coated on the surface of the porous support layer. The porous support layer comprises modified hydrophobic polymer fibers and an antimicrobial filler attached to the surface of the modified hydrophobic polymer fibers. After surface modification, polar oxygen-containing functional groups are generated on the surface of the hydrophobic polymer fibers. This allows the functional agent to be bonded to the surface of the hydrophobic polymer fibers through electrostatic interactions, hydrogen bonds, or covalent bonds, forming the porous support layer. Bonding the functional agent to the surface of the hydrophobic polymer fibers not only imparts the properties of the corresponding functional agent to the total heat exchange membrane, but also effectively prevents the introduction of excessive filler into the functional dense layer, thereby preventing filler clogging or blocking the total heat exchange membrane, thereby maintaining excellent thermal and moisture performance and total heat exchange capacity. Furthermore, the low filler content reduces disruption to the continuity of the hydrophilic polymer matrix in the functional dense layer, thereby maintaining high airtightness of the total heat exchange membrane. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, a brief introduction will be given below to the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative labor.

[0020] Figure 1 is a flow chart of the preparation process of the porous supporting layer of the present invention; Figure 2 Schematic diagram of the structure of the full heat exchange membrane in Example 1 of the present invention; Figure 3 This is an enlarged schematic diagram of the structure of the porous support layer in Example 1 of the present invention; Figure 4 Schematic diagram of the structure of the porous support membrane in Example 2 of the present invention; Figure 5 Schematic diagram of the structure of the porous support membrane in Example 3 of the present invention; Other features and advantages of the present invention will become more apparent after reading the detailed description of the present invention in conjunction with the accompanying drawings. DETAILED DESCRIPTION

[0021] The following will be combined with the drawings in the embodiments of this application to clearly and completely describe the technical solutions in the embodiments of this application. Obviously, the embodiments described are only part of the embodiments of this application, not all of the embodiments. Based on the embodiments in this application, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of this application.

[0022] In the description of this application, it should be understood that the terms "center", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", etc., indicating the orientation or position relationship, are based on the orientation or position relationship shown in the accompanying drawings, and are only for the convenience of describing this application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation on this application.

[0023] The terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of the technical features being referred to. Thus, a feature specified as "first" or "second" may explicitly or implicitly include one or more of such features. Throughout this application, unless otherwise specified, "plurality" means two or more.

[0024] In the description of this application, it should be noted that, unless otherwise expressly specified or limited, the terms "mounted," "connected," and "connected" should be understood in a broad sense. For example, they can refer to fixed connections, detachable connections, or integral connections; mechanical connections or electrical connections; direct connections or indirect connections through an intermediate medium; and internal connections between two components. Those skilled in the art will understand the specific meanings of the above terms in this application based on the specific circumstances.

[0025] In the present invention, unless otherwise expressly specified or limited, a first feature being "above" or "below" a second feature may include the first and second features being in direct contact, or may include the first and second features being in contact not directly but through another feature between them. Furthermore, a first feature being "above," "above," and "above" a second feature may include the first feature being directly above or obliquely above the second feature, or may simply mean that the first feature is higher in level than the second feature. A first feature being "below," "below," and "below" a second feature may include the first feature being directly below or obliquely below the second feature, or may simply mean that the first feature is lower in level than the second feature.

[0026] The disclosure below provides many different embodiments or examples for realizing different structures of the present invention. In order to simplify the disclosure of the present invention, the components and settings of specific examples are described below. Of course, they are merely examples and are not intended to limit the present invention. In addition, the present invention may repeat reference numbers and / or reference letters in different examples. Such repetition is for the purpose of simplicity and clarity and does not in itself indicate the relationship between the various embodiments and / or settings discussed. In addition, the present invention provides examples of various specific processes and materials, but those skilled in the art will recognize the application of other processes and / or the use of other materials.

[0027] The full heat exchange membrane of the present invention comprises a porous support layer and a functional dense layer coated on the surface of the porous support layer.

[0028] The porous supporting layer comprises modified hydrophobic polymer fibers and a functional agent attached to the surface of the modified hydrophobic polymer fibers.

[0029] The functional dense layer includes a hydrophilic polymer matrix and a filler.

[0030] After the hydrophobic polymer fiber is surface-modified, polar oxygen-containing functional groups are generated on the surface of the hydrophobic polymer fiber, so that the functional agent can be compounded on the surface of the hydrophobic polymer fiber through electrostatic action, hydrogen bonding or covalent bonding to form a porous support layer.

[0031] Functional agents are compounded on the surface of the hydrophobic polymer fiber. The functional agents may include antibacterial agents, flame retardants, thermal conductors, hygroscopic agents, etc., and are not specifically limited here. Functional agents can impart antibacterial, flame retardant, thermal conductive, hygroscopic or other properties to the full heat exchange membrane. At the same time, it can also effectively avoid the introduction of excessive fillers into the functional dense layer, and avoid excessive fillers clogging or blocking the full heat exchange membrane, so that the full heat exchange membrane can maintain excellent thermal and moisture performance and full heat exchange capacity; in addition, the small amount of filler used can also reduce the damage to the continuity of the hydrophilic polymer substrate in the functional dense layer, thereby allowing the full heat exchange membrane to maintain a higher airtightness.

[0032] When the functional agent includes an antimicrobial agent, the full heat exchange membrane can be endowed with antimicrobial properties. Antimicrobial agents include one or more of graphene, nanosilver, silver ion compounds, quaternary ammonium salts, and titanium dioxide. When a quaternary ammonium salt is used as the antimicrobial agent, the aqueous solution of the quaternary ammonium salt carries a positive charge, which can electrostatically bind to the hydroxyl (negatively charged) functional groups on the surface of the hydrophobic polymer fibers. This allows the quaternary ammonium salt to be incorporated into the surface of the hydrophobic polymer fibers, imparting antimicrobial properties to the porous support layer.

[0033] When the functional agent includes a flame retardant, it can impart flame retardancy to the full heat exchange membrane. The flame retardant includes at least one of an inorganic flame retardant and an organic flame retardant. Inorganic flame retardants include at least one of aluminum hydroxide, aluminum chloride, magnesium oxide, and silicon-based flame retardants. Organic flame retardants include at least one of ammonium polyphosphate, antimony polyphosphate, ammonium bromide, and chlorinated polyolefins. When ammonium polyphosphate is used as a flame retardant, the positive charge in its aqueous solution allows it to electrostatically bind to the hydroxyl (negatively charged) functional groups on the surface of the hydrophobic polymer fibers, thereby imparting flame retardancy to the porous support layer.

[0034] When the functional agent includes a thermal conductor, thermal conductivity can be imparted to the full heat exchange membrane. The thermal conductor includes at least one of carbon nanotubes, silver nanowires, graphite, carbon fibers, boron nitride, and aluminum oxide. When water-soluble silver nanowires are used as the thermal conductor, they can form bonds with functional groups such as hydroxyl groups on the surface of the hydrophobic polymer fibers through hydrogen bonding and van der Waals forces. Thus, the water-soluble silver nanowires can be bonded to the surface of the hydrophobic polymer fibers, imparting thermal conductivity to the porous support layer.

[0035] The ratio of the functional agent content to the modified hydrophobic polymer fiber content is X. If X is too low, the functional agent cannot fully exert its functionality. Therefore, X is set to be greater than the first parameter value. For example, the first parameter value can be 1%, 1.5%, or 1.8%. The selection of a suitable parameter is considered during the specific design and is not specifically limited here.

[0036] If X is too high, the functional agent will clog the pores of the porous support layer, reducing its heat and moisture exchange performance. Therefore, X is set to be less than the second parameter value. For example, the second parameter value can be 30%, 25%, or 20%. The selection of an appropriate parameter will be considered during the specific design and is not specifically limited here.

[0037] Preferably, in the present invention, X may be greater than or equal to 2%, and X may be less than or equal to 20%. Within this range, the functional agent can fully exert its functionality to impart corresponding performance to the full heat exchange membrane; at the same time, it will not affect or reduce the heat and moisture exchange performance of the porous support layer.

[0038] If the thickness L of the porous support layer is too low, it will make processing of the porous support layer more difficult, which in turn will affect the processing efficiency and yield of the full heat exchange membrane. Therefore, the thickness L of the porous support layer is greater than the first parameter value. For example, the first parameter value can be 9μm, 10μm, or 12μm. The selection of an appropriate parameter is considered during the specific design and is not specifically limited here.

[0039] If the thickness L of the porous support layer is too high, it will increase the heat and mass transfer resistance during the heat and moisture transfer process, reduce the effective air duct volume in the full heat exchange membrane, and reduce the exchange efficiency of the full heat exchange membrane. Therefore, the thickness L of the porous support layer is set to be less than the second parameter value. For example, the second parameter value can be 40μm, 35μm, or 30μm. The selection of an appropriate parameter will be considered during the specific design and is not specifically limited here.

[0040] The present invention can optimize the thickness L of the porous support layer to ensure that the porous support layer is easy to process, with high processing efficiency and yield rate, while not increasing the heat and mass transfer resistance, not reducing the effective air duct volume in the full-heat product, and not reducing the exchange efficiency of the full-heat product.

[0041] Preferably, in the present invention, the thickness L of the porous support layer can be greater than or equal to 12 μm, and L can be less than or equal to 25 μm. Within this range, the processing efficiency and yield of the full-heat product can be maximized, and the heat and mass transfer resistance can be greatly reduced, the effective air duct volume in the full-heat product can be maximized, and the exchange efficiency of the full-heat product can be improved.

[0042] If the porosity K of the porous support layer is too low, the heat and mass transfer resistance during heat and moisture transfer in the porous support layer will increase, reducing the exchange efficiency of the full heat exchange membrane. Therefore, the porosity K of the porous support layer is set to be greater than the first parameter value. For example, the first parameter value can be 30% or 35%. The selection of an appropriate parameter will be considered during the specific design and is not specifically limited here.

[0043] If the porosity K of the porous support layer is too high, it will be difficult to apply the coating liquid to the functional dense layer. Therefore, the porosity of the porous support layer is set to be less than the second parameter value. For example, the second parameter value can be 80% or 85%. The selection of an appropriate parameter will be considered during the specific design and is not specifically limited here.

[0044] The present invention can ensure that the mass transfer resistance of the support layer portion is not too large by optimizing the porosity K of the porous support layer, and is also beneficial to the coating process of the dense layer coating liquid.

[0045] Preferably, in the present invention, the porosity K of the porous support layer can be greater than 55%, and K can be less than 80%. Within this range, the coating process of the dense layer coating liquid can be smoothly implemented while minimizing the mass transfer resistance of the support layer.

[0046] If the pore size T of the porous support layer is too small, the mass transfer resistance of the porous support layer will be too high. Therefore, the pore size T of the porous support layer is set to be greater than the first parameter value. For example, the first parameter value can be 50 nm. The selection of an appropriate parameter is considered during the specific design and is not specifically limited here.

[0047] If the pore size T of the porous support layer is too large, it will hinder the coating process of the functional dense layer coating liquid. Therefore, the pore size T of the porous support layer is smaller than the second parameter value. For example, the second parameter value can be 3 μm. The selection of an appropriate parameter will be considered during the specific design and is not specifically limited here.

[0048] The present invention can optimize the pore size T of the porous support layer to ensure that the coating process of the dense layer coating liquid is favorable, and will not cause excessive mass transfer resistance of the support layer.

[0049] Preferably, in the present invention, the pore size T of the porous support layer can be greater than or equal to 50 nm, and T can be less than or equal to 500 nm; within this range, the coating process of the dense layer coating liquid can be smoothly implemented while minimizing the mass transfer resistance of the support layer.

[0050] If the surface density N of the hydrophobic polymer fiber is too small, it is not conducive to the coating process of the dense layer coating liquid. Therefore, the surface density of the hydrophobic polymer fiber is greater than the first parameter value. For example, the first parameter value can be 5g / m 2 , 6g / m 2 , 7g / m 2 , when designing specifically, consider choosing a suitable specific parameter, and no specific restrictions are made here.

[0051] If the surface density N of the hydrophobic polymer fibers is too large, the mass transfer resistance of the support layer will be too large. Therefore, the surface density N of the hydrophobic polymer fibers is made smaller than the second parameter value. For example, the second parameter value can be 30 g / m 2 , 35g / m 2 , 40g / m 2 , when designing specifically, consider choosing a suitable specific parameter, and no specific restrictions are made here.

[0052] The present invention can ensure that the dense layer coating liquid can be smoothly coated and processed by optimizing the surface density N of the hydrophobic polymer fiber, and will not cause excessive mass transfer resistance in the support layer.

[0053] Preferably, in the present invention, the surface density N of the hydrophobic polymer fiber can be greater than or equal to 8 g / m 2 , N can be less than or equal to 12g / m 2 Within this range, the dense layer coating liquid can be effectively coated and processed smoothly without causing excessive mass transfer resistance in the supporting layer.

[0054] The hydrophobic polymer fiber can be at least one of a polymer-based hydrophobic fiber such as polyethylene (PE) fiber, polypropylene (PP) fiber, polyester (PET) fiber, or polystyrene (PS) fiber, without specific limitation. The porous support layer utilizes hydrophobic polymer fibers, which do not absorb a significant amount of water molecules. Water molecules are unable to penetrate the fibers, thereby preventing the porous support layer from increasing its moisture resistance.

[0055] If the thickness M of the functional dense layer is too small, the airtightness of the functional dense layer will be greatly reduced. Therefore, the thickness of the functional dense layer is set to be greater than the first parameter value. For example, the first parameter value can be 0.1 μm. The selection of an appropriate parameter is considered in the specific design and is not specifically limited here.

[0056] If the thickness M of the functionally dense layer is too large, the mass transfer resistance of water molecules through the functionally dense layer will be significantly increased. Therefore, the thickness of the functionally dense layer is preferably less than the second parameter value. For example, the second parameter value can be 1 μm, 1.5 μm, or 2 μm. The selection of an appropriate parameter is considered during the specific design and is not specifically limited here.

[0057] The present invention can ensure that the air tightness of the functional dense layer will not be significantly reduced, and the mass transfer resistance of water molecules passing through the functional dense layer will not be significantly increased by optimizing the thickness M of the functional dense layer.

[0058] Preferably, in the present invention, the thickness M of the functional dense layer can be greater than or equal to 0.1 μm, and M can be less than or equal to 0.5 μm; within this range, it can effectively ensure that the air tightness of the functional dense layer will not be significantly reduced, nor will it significantly increase the mass transfer resistance of water molecules passing through the functional dense layer.

[0059] The antibacterial filler includes one or more of graphene, nanosilver, silver ion compounds, quaternary ammonium salts, and titanium dioxide (TiO2), and is not specifically limited here.

[0060] The hydrophilic polymer substrate includes one or more hydrophilic polymers such as polyvinyl alcohol (PVA), polyvinyl pyrrolidone (PVP), polyurethane (PU), polyacrylic acid resin (PAA), etc., and is not specifically limited here.

[0061] The filler includes a hygroscopic filler, which can impart excellent hygroscopic properties to the dense layer.

[0062] The hygroscopic filler includes one or more of lithium chloride (LiCl), calcium chloride (CaCl2), sodium chloride (NaCl), potassium chloride (KCl), carboxymethyl cellulose (CMC), chitosan, and metal organic framework compounds (MOF), and is not specifically limited here.

[0063] If the hygroscopic filler content is too low, the functional dense layer will not have good hygroscopic properties. Therefore, the ratio S of the hygroscopic filler content to the hydrophilic polymer substrate content is set to be greater than the first parameter value. For example, the first parameter value can be 1% or 1.5%. The selection of an appropriate parameter is considered during the specific design and is not specifically limited here.

[0064] If the hygroscopic filler content is too high, it will affect the continuity of the hydrophilic polymer matrix and reduce the airtightness of the functional dense layer. Therefore, the ratio S of the hygroscopic filler content to the hydrophilic polymer matrix content is set to be less than the second parameter value. For example, the second parameter value can be 20%, 25%, or 30%. The selection of an appropriate parameter will be considered during the specific design and is not specifically limited here.

[0065] The present invention can ensure that the functional dense layer has excellent hygroscopic properties by optimizing the ratio S of the hygroscopic filler content to the hydrophilic polymer substrate content, without affecting the continuity of the dense layer polymer matrix or damaging the air tightness of the dense layer.

[0066] Preferably, in the present invention, the ratio S of the hygroscopic filler content to the hydrophilic polymer substrate content can be greater than or equal to 2%, and S can be less than or equal to 10%; within this range, it can effectively ensure that the functional dense layer has excellent hygroscopic properties, and will not affect the continuity of the dense layer polymer matrix, and will not damage the air tightness of the dense layer.

[0067] The filler includes a thermally conductive filler, which can impart excellent thermal conductivity to the dense layer. The thermally conductive filler includes at least one of graphene, carbon nanotubes, silver nanowires, graphite, carbon fiber, boron nitride, and aluminum oxide.

[0068] If the thermally conductive filler content is too low, the functionally dense layer will not have excellent thermally conductive filler properties. Therefore, the ratio D of the thermally conductive filler content to the hydrophilic polymer substrate content is set to be greater than the first parameter value. For example, the first parameter value can be 1% or 1.5%. The selection of an appropriate parameter is considered during the specific design and is not specifically limited here.

[0069] If the thermally conductive filler content is too high, it will affect the continuity of the hydrophilic polymer matrix and reduce the airtightness of the functional dense layer. Therefore, the ratio D of the thermally conductive filler content to the hydrophilic polymer matrix content is set to be less than the second parameter value. For example, the second parameter value can be 20%, 25%, or 30%. The selection of an appropriate parameter will be considered during the specific design and is not specifically limited here.

[0070] The present invention can ensure that the functional dense layer has excellent thermal conductivity by optimizing the ratio D of the thermal conductive filler content to the hydrophilic polymer base material content, without affecting the continuity of the dense layer polymer matrix or damaging the air tightness of the dense layer.

[0071] Preferably, in the present invention, the ratio D of the thermal conductive filler content to the hydrophilic polymer substrate content can be greater than or equal to 2%, and D can be less than or equal to 10%; within this range, it can effectively ensure that the functional dense layer has excellent thermal conductivity, and will not affect the continuity of the dense layer polymer matrix, and will not damage the air tightness of the dense layer.

[0072] The filler includes an antibacterial filler, which can impart excellent antibacterial properties to the dense layer.

[0073] The antibacterial filler includes one or more of graphene, nanosilver, silver ion compounds, quaternary ammonium salts, and titanium dioxide (TiO2).

[0074] If the antimicrobial filler content is too low, the functional dense layer will not have excellent antimicrobial filler properties. Therefore, the ratio E of the antimicrobial filler content to the hydrophilic polymer substrate content is set to be greater than the first parameter value. For example, the first parameter value can be 1%, 1.5%, or 2%. The selection of an appropriate parameter is considered during the specific design and is not specifically limited here.

[0075] If the antimicrobial filler content is too high, it will affect the continuity of the hydrophilic polymer matrix and reduce the airtightness of the functional dense layer. Therefore, the ratio E of the antimicrobial filler content to the hydrophilic polymer matrix content is set to be less than the second parameter value. For example, the second parameter value can be 6%, 8%, or 10%. The selection of an appropriate parameter will be considered during the specific design and is not limited here.

[0076] The present invention can ensure that the functional dense layer has excellent antibacterial properties by optimizing the ratio E of the antibacterial filler content to the hydrophilic polymer base material content, without affecting the continuity of the dense layer polymer matrix or damaging the air tightness of the dense layer.

[0077] Preferably, in the present invention, the ratio E of the antibacterial filler content to the hydrophilic polymer substrate content can be greater than or equal to 2%, and E can be less than or equal to 5%; within this range, it can effectively ensure that the functional dense layer has excellent antibacterial properties without affecting the continuity of the dense layer polymer matrix or damaging the air tightness of the dense layer.

[0078] The filler includes a porogenic filler, which can form a pore structure in the dense layer to improve the moisture absorption and thermal conductivity of the dense layer. The porogenic filler includes at least one of polyethylene glycol and silica gel, which is not specifically limited here.

[0079] If the porogenic filler content is too low, the moisture absorption and thermal conductivity of the functional dense layer will be reduced. Therefore, the ratio H of the porogenic filler content to the hydrophilic polymer substrate content is set to be greater than the first parameter value. For example, the first parameter value can be 1%, 1.5%, or 2%. The selection of an appropriate parameter is considered during the specific design and is not specifically limited here.

[0080] If the porogenic filler content is too high, it will affect the continuity of the hydrophilic polymer matrix and reduce the airtightness of the functional dense layer. Therefore, the ratio H of the porogenic filler content to the hydrophilic polymer matrix content is set to be less than the second parameter value. For example, the second parameter value can be 6%, 8%, or 10%. The selection of an appropriate parameter is considered in the specific design and is not specifically limited here.

[0081] The present invention can ensure that the functional dense layer has excellent moisture absorption and thermal conductivity by optimizing the ratio H of the porogenic filler content to the hydrophilic polymer substrate content, without affecting the continuity of the dense layer polymer matrix or damaging the air tightness of the dense layer.

[0082] Preferably, in the present invention, the ratio H of the porogenic filler content to the hydrophilic polymer substrate content can be greater than or equal to 2%, and H can be less than or equal to 5%; within this range, it can effectively ensure that the functional dense layer has excellent moisture absorption and thermal conductivity, and will not affect the continuity of the dense layer polymer matrix, and will not damage the air tightness of the dense layer.

[0083] The preparation method of the full heat exchange membrane of the present invention comprises: (1) A PP hydrophobic fiber membrane prepared by a dry casting stretching process was used to prepare the hydrophobic polymer fiber. The PP hydrophobic fiber membrane has a thickness of 20 μm, a porosity of 55%, and a pore size of 300 nm. It can ensure a low mass transfer resistance of the support layer while meeting the coating process of the dense layer.

[0084] The specific dry casting and stretching process is a common process in the art and is not specifically limited herein. Alternatively, the PP hydrophobic fiber membrane can be a commercially available PP hydrophobic fiber membrane, as long as the PP hydrophobic fiber membrane has a thickness of 20 μm, a porosity of 55%, and a pore size of 300 nm.

[0085] (2) The hydrophobic polymer fiber is surface modified to obtain a modified hydrophobic polymer fiber.

[0086] The surface modification method can be high-temperature melting. The high-temperature melting treatment process is to melt a part of the outer surface of the fiber at high temperature, thereby facilitating the embedding of some high surface energy functional agents. After cooling, a modified layer embedded with the functional agent is formed on the fiber surface.

[0087] The surface modification method can be corona discharge treatment. The corona discharge treatment process generates electrons and positive and negative ions through localized discharge. Through interaction with the fiber surface, free radicals and ions are generated on the surface, thereby forming polar oxygen-containing functional groups, which facilitate the attachment of functional agents to the fiber surface through interactions such as electrostatic effects, hydrogen bonds, and covalent bonds. The discharge current can be greater than or equal to 100mA and less than or equal to 300mA. Within this range, the hydrophobic polymer fiber can be fully corona-discharged to form sufficient polar functional groups such as hydroxyl groups, carboxyl groups, and sulfonic acid groups on the fiber surface, thereby facilitating the attachment of functional agents to the fiber surface through interactions such as electrostatic effects, hydrogen bonds, and covalent bonds.

[0088] The surface modification method can be plasma treatment. Plasma treatment involves placing the fiber in a low-temperature plasma environment in a non-reactive or reactive gas to generate oxygen-containing functional groups or free radicals on the fiber surface. Non-reactive gases include argon and helium, while reactive gases include oxygen, nitrogen, and carbon dioxide, with oxygen being preferred.

[0089] The surface modification method can be a chemical oxidation process. This application uses a hydrochloric acid-potassium permanganate system chemical oxidation process to modify the surface of the hydrophobic polymer fiber. The hydrophobic polymer fiber is immersed and stirred in a hydrochloric acid-potassium permanganate system solution. The immersion and stirring treatment time can be greater than or equal to 8 hours, and the immersion and stirring treatment time can be less than or equal to 24 hours. The hydrophobic polymer fiber can be fully surface-modified to form sufficient polar functional groups such as hydroxyl groups, carboxyl groups, and sulfonic acid groups on the fiber surface, thereby facilitating the attachment of the functional agent to the fiber surface through interactions such as electrostatic effects, hydrogen bonds, and covalent bonds.

[0090] The mass ratio of hydrochloric acid to potassium permanganate is 5-15:85-95, which can fully modify the hydrophobic polymer fiber, so that a sufficient number of polar oxygen-containing functional groups or free radicals are generated on the surface of the hydrophobic polymer fiber to strengthen the mutual cross-linking effect between the fiber surface and the antibacterial filler, thereby allowing more functional agents to adhere to the surface of the hydrophobic polymer fiber.

[0091] The hydrophobic polymer fiber after the immersion treatment is cleaned and dried, and the treated hydrophobic polymer fiber is repeatedly cleaned with deionized water until the pH value of the cleaning solution is greater than 6. The number of cleaning times can be greater than or equal to 5 times, and the number of cleaning times can be less than or equal to 15 times, and the hydrophobic polymer fiber can be fully cleaned.

[0092] In step (2), a polar high molecular polymer is also grown in situ on the surface of the hydrophobic polymer fiber after the impregnation treatment to increase the number of polar functional groups on the fiber surface and strengthen the interaction between the fiber surface and the functional agent, so that more functional agents can be attached to the surface of the hydrophobic polymer fiber. The specific steps are: aniline monomer is in situ polymerized on the surface of the hydrophobic polymer fiber after the impregnation treatment to generate polyaniline, and hydrochloric acid is used as a solvent during the in situ polymerization process, wherein the molar concentration of hydrochloric acid is less than or equal to 12 mol / L and greater than or equal to 2 mol / L, which can induce the aniline monomer to fully polymerize on the surface of the hydrophobic polymer fiber to generate polyaniline, so as to maximize the number of polar functional groups on the fiber surface and strengthen the interaction between the fiber surface and the functional agent, so that more functional agents can be attached to the surface of the hydrophobic polymer fiber.

[0093] The polymerization reaction temperature is greater than or equal to -4°C and less than or equal to 0°C, and the polymerization reaction time is greater than or equal to 4 hours and less than or equal to 12 hours, so that the aniline monomer can be fully polymerized on the surface of the hydrophobic polymer fiber to generate polyaniline, so as to maximize the number of polar functional groups on the fiber surface and strengthen the interaction between the fiber surface and the functional agent, so that more functional agents can be attached to the surface of the hydrophobic polymer fiber.

[0094] During the in-situ polymerization process, ammonium persulfate is used as an initiator for the polymerization of aniline monomer. The mass ratio of aniline monomer to ammonium persulfate is 30-50:50-80, which can ensure that the aniline monomer is fully polymerized in situ on the surface of the hydrophobic polymer fiber. The polymerization degree of the aniline monomer ensures that a sufficient amount of polyaniline grows on the surface of the hydrophobic polymer fiber, thereby increasing the number of polar functional groups on the fiber surface and strengthening the interaction between the fiber surface and the functional agent, so that more functional agents can be attached to the surface of the hydrophobic polymer fiber.

[0095] (3) The functional agent is attached to the modified hydrophobic polymer fiber by solution blending to obtain a porous support layer; Figure 1FIG. 1 is a flow chart of the preparation process of the porous support layer of the present invention; Solution blending involves ultrasonically dispersing the functional agent in a solvent, followed by repeated immersion of the modified fiber membrane in the solution to adhere the functional agent to the modified fiber surface. The solvent includes one or a mixture of water, ethanol, methanol, acetone, N'N-dimethylformamide, N'N-dimethylacetamide, and dimethyl sulfoxide. The ultrasonication time is greater than or equal to 1 hour and less than or equal to 4 hours, and the number of immersions is greater than or equal to 10 and less than or equal to 50 times, ensuring that the functional agent is fully bonded to the surface of the modified hydrophobic polymer fiber.

[0096] Specifically, the functional agent is ultrasonically dispersed in a deionized water solvent to prepare a functional impregnation solution, wherein the mass fraction of the functional agent can be greater than or equal to 3wt% and less than or equal to 10wt%. Within this range, the functional agent can fully exert its functionality to give the full heat exchange membrane corresponding performance; at the same time, it will not affect or reduce the heat and moisture exchange performance of the porous support layer.

[0097] The modified hydrophobic polymer fiber is repeatedly immersed in the functional impregnation liquid, and after being immersed for a few seconds, it is placed in an oven to dry and remove the solvent, so that the functional agent is attached to the surface of the hydrophobic polymer fiber, wherein the number of immersion-drying cycles can be greater than or equal to 10 times and less than or equal to 30 times.

[0098] (4) dissolving the hydrophilic polymer substrate in a solvent, adding fillers, and mixing uniformly by ultrasonication and stirring to obtain a dense layer coating solution; The solvent includes one or a mixed solvent of deionized water, ethanol, methanol, acetone, N'N-dimethylformamide, N'N-dimethylacetamide, and dimethyl sulfoxide.

[0099] The ultrasonic time can be greater than or equal to 1 hour and less than or equal to 4 hours, and the stirring time can be greater than or equal to 2 hours and less than or equal to 12 hours. Within this range, the hydrophilic polymer substrate and the filler can be fully mixed.

[0100] In this application, water-based polyurethane can be selected as the hydrophilic polymer substrate, deionized water can be used as the solvent, CaCl2 can be selected as the hygroscopic filler, silver nanowires can be used as the thermal conductive filler, quaternary ammonium salts can be used as the antibacterial filler, and PEG can be used as the porogenic filler.

[0101] In the present invention, the mass ratio of waterborne polyurethane, CaCl2, silver nanowires, quaternary ammonium salt, and PEG can be 70-98:1-20:1-10:0.1-5:1-5; within this range, it can effectively ensure that the functional dense layer has excellent antibacterial, moisture absorption, thermal conductivity and other properties, and will not affect the continuity of the dense layer polymer matrix or damage the air tightness of the dense layer.

[0102] (5) Coating the dense layer coating solution on the surface of the porous support layer and drying in an oven to obtain the full heat exchange membrane. The drying temperature can be greater than or equal to 40° C. and less than or equal to 70° C., and the drying time can be greater than or equal to 1 hour and less than or equal to 4 hours, so as to achieve sufficient and thorough drying and ensure that the dense layer coating solution is fully cross-linked on the surface of the porous support layer.

[0103] If the coating layer is too thin, the airtightness of the functional dense layer will be greatly reduced. Therefore, the thickness of the functional dense layer is set to be greater than the first parameter value. For example, the first parameter value can be 0.1 μm. The selection of an appropriate parameter is considered in the specific design and is not specifically limited here.

[0104] If the coating layer is too thick, it will significantly increase the mass transfer resistance of water molecules through the functional dense layer. Therefore, the thickness of the functional dense layer is set to be less than the second parameter value. For example, the second parameter value can be 0.5 μm. The selection of an appropriate parameter will be considered during the specific design and is not specifically limited here.

[0105] In the present invention, the coating layer thickness can be greater than or equal to 0.1 μm and less than or equal to 0.5 μm; within this range, it can effectively ensure that the air tightness of the functional dense layer will not be significantly reduced, and the mass transfer resistance of water molecules passing through the functional dense layer will not be significantly increased.

[0106] The coating process includes at least one of calendering, casting, scraping, etc. The present application adopts the scraping process to evenly coat the coating solution on the surface of the modified porous support layer, and places it in an oven to dry to obtain a full heat exchange membrane.

[0107] The total heat exchanger of the present invention includes the total heat exchange membrane of the present invention. The total heat exchange membrane of the present invention can be assembled into a total heat exchange element according to existing known methods and used in the total heat exchanger.

[0108] The total heat exchanger of the present invention has excellent antibacterial properties, thermal and moisture properties, and total heat exchange capacity. It can provide fresh air indoors, remove indoor polluted air, and improve indoor air quality. At the same time, it can recover HVAC energy (both sensible heat and latent heat), thereby saving energy and reducing emissions in building HVAC. It will effectively and effectively promote the country's "energy conservation and emission reduction" process, and has far-reaching strategic significance and good social benefits. Example 1

[0109] The preparation method of the full heat exchange membrane of this embodiment includes: (1) The PP hydrophobic fiber membrane prepared by the common casting and stretching process on the market was used to prepare the hydrophobic polymer fiber. The selected PP hydrophobic fiber membrane had a thickness of 20 μm, a porosity of 55%, and a pore size of 300 nm.

[0110] (2) The PP hydrophobic fiber membrane was immersed in a hydrochloric acid-potassium permanganate system solution and stirred for 10 hours to modify the surface of the PP hydrophobic fiber membrane. The mass ratio of hydrochloric acid to potassium permanganate was 15:85.

[0111] The hydrophobic polymer fibers after the immersion treatment are cleaned and dried, and the treated hydrophobic polymer fibers are repeatedly cleaned with deionized water until the pH value of the cleaning solution is greater than 6, and the number of cleaning times is 10.

[0112] Aniline monomer is in situ polymerized into polyaniline on the surface of the hydrophobic polymer fiber after impregnation treatment, wherein ammonium persulfate is used as an initiator for the polymerization of the aniline monomer, hydrochloric acid is used as a solvent, wherein the hydrochloric acid concentration is 2M, wherein the polymerization reaction temperature is -4°C, and wherein the polymerization reaction time is 12 hours.

[0113] The polymerization temperature of the in-situ polymerization of aniline on the fiber surface was -4°C, the polymerization time was 10 hours, and the mass ratio of aniline monomer to ammonium persulfate was 50:50.

[0114] (3) Ultrasonic dispersion of the functional agent in the solvent for 4 hours and 50 immersions. The modified fiber membrane is then repeatedly immersed in the solution to allow the functional agent to adhere to the modified hydrophobic polymer fiber, thereby obtaining a porous support layer.

[0115] The quaternary ammonium salt is ultrasonically dispersed in a deionized water solvent to prepare an antibacterial functional impregnation solution, wherein the content of the quaternary ammonium salt is 10wt%, and the content of the deionized water solvent is 90wt%.

[0116] The modified PP fiber was repeatedly immersed in the antibacterial functional impregnation solution for a few seconds, and then placed in an oven to dry and remove the solvent, so that the quaternary ammonium salt antibacterial filler was attached to the surface of the hydrophobic polymer fiber. The number of immersion-drying cycles was 30.

[0117] (4) dissolving the hydrophilic polymer substrate in deionized water, adding filler, and mixing uniformly by ultrasonication and stirring to obtain a dense layer coating solution; The filler ratio was 15%, the ultrasonic time was 4 hours, and the stirring time was 10 hours.

[0118] Waterborne polyurethane is selected as the hydrophilic polymer matrix, deionized water is used as the solvent, CaCl2 is selected as the hygroscopic filler, silver nanowires are selected as the thermal conductive filler, quaternary ammonium salts are selected as the antibacterial filler, and PEG is selected as the porogenic filler.

[0119] The mass ratio of waterborne polyurethane, CaCl2, silver nanowires, quaternary ammonium salt, and PEG is 85:5:5:2:3.

[0120] (5) coating the dense layer coating solution on the surface of the porous support layer and drying it in an oven to obtain the full heat exchange membrane.

[0121] The drying temperature was 70° C., the drying time was 4 hours, and the coating layer thickness was 0.5 μm.

[0122] The coating process includes at least one of calendering, casting, scraping, etc. The present application adopts the scraping process to evenly coat the coating solution on the surface of the modified porous support layer, and places it in an oven to dry to obtain a full heat exchange membrane.

[0123] Testing revealed that the resulting full heat exchange membrane had a moisture permeability of 3970 g / m2 / 24 hours (GB / T 1037 standard), a thermal conductivity of 0.42 W / mK, and an antibacterial rate of 99.9% (GB 21551.2 standard). This demonstrates that the resulting full heat exchange membrane possesses excellent antibacterial and purification properties, while exhibiting high heat and moisture transfer capabilities.

[0124] like Figure 2 、 Figure 3 , which is a schematic structural diagram of the porous support membrane of this embodiment. The antibacterial agent is a small molecule material, which is dispersed on the surface of the modified hydrophobic polymer fiber and can give the modified hydrophobic polymer fiber excellent antibacterial properties. Example 2

[0125] The preparation method of the full heat exchange membrane of this embodiment includes: (1) The PP hydrophobic fiber membrane prepared by the common casting and stretching process on the market was used to prepare the hydrophobic polymer fiber. The selected PP hydrophobic fiber membrane had a thickness of 16 μm, a porosity of 45%, and a pore size of 300 nm.

[0126] (2) The PP hydrophobic fiber membrane was immersed in a hydrochloric acid-potassium permanganate system solution and stirred for 10 hours to modify the surface of the PP hydrophobic fiber membrane. The mass ratio of hydrochloric acid to potassium permanganate was 20:80.

[0127] The hydrophobic polymer fibers after the immersion treatment are cleaned and dried, and the treated hydrophobic polymer fibers are repeatedly cleaned with deionized water until the pH value of the cleaning solution is greater than 6, and the number of cleaning times is 10.

[0128] Aniline monomer is in situ polymerized into polyaniline on the surface of the hydrophobic polymer fiber after impregnation treatment, wherein ammonium persulfate is used as an initiator for the polymerization of the aniline monomer, hydrochloric acid is used as a solvent, wherein the hydrochloric acid concentration is 2M, wherein the polymerization reaction temperature is -4°C, and wherein the polymerization reaction time is 12 hours.

[0129] The polymerization temperature of the in-situ polymerization of aniline on the fiber surface was -4°C, the polymerization time was 10 hours, and the mass ratio of aniline monomer to ammonium persulfate was 50:50.

[0130] (3) The flame retardant is ultrasonically dispersed in the solvent for 4 hours and 50 times. The modified fiber membrane is then repeatedly immersed in the solution to allow the flame retardant to adhere to the modified hydrophobic polymer fiber, thereby obtaining a flame-retardant porous support layer.

[0131] Ammonium polyphosphate is ultrasonically dispersed in deionized water solvent to prepare a flame retardant functional impregnation solution, wherein the content of ammonium polyphosphate is 10wt% and the content of deionized water solvent is 90wt%.

[0132] The modified PP fiber was repeatedly immersed in the flame retardant functional impregnation liquid. After being immersed for a few seconds, it was placed in an oven to dry and remove the solvent, so that the ammonium polyphosphate flame retardant adhered to the surface of the hydrophobic polymer fiber. The number of immersion-drying cycles was 30.

[0133] (4) dissolving the hydrophilic polymer substrate in deionized water, adding filler, and mixing uniformly by ultrasonication and stirring to obtain a dense layer coating solution; The filler ratio was 15%, the ultrasonic time was 4 hours, and the stirring time was 10 hours.

[0134] Waterborne polyurethane is selected as the hydrophilic polymer matrix, deionized water is used as the solvent, LiCl is selected as the hygroscopic filler, boron nitride is selected as the thermal conductive filler, quaternary ammonium salt is selected as the antibacterial filler, and PEG is selected as the pore-forming filler.

[0135] The mass ratio of water-based acrylic resin, LiCl, boron nitride, quaternary ammonium salt, and PEG is 85:5:5:2:3.

[0136] (5) coating the dense layer coating solution on the surface of the flame retardant porous support layer and drying it in an oven to obtain the flame retardant full heat exchange membrane.

[0137] The drying temperature was 70° C., the drying time was 4 hours, and the coating layer thickness was 0.5 μm.

[0138] The coating process includes at least one of calendering, casting, scraping, etc. The present application adopts the scraping process to evenly coat the coating solution on the surface of the modified flame retardant porous support layer, and places it in an oven to dry to obtain a flame retardant full heat exchange membrane.

[0139] The flame retardant heat exchange membrane has a moisture permeability of 3775 g / ㎡·24h (GB / T 1037 standard), a thermal conductivity of 0.35 W / mK, and a CO2 permeability of 3.3×10 5 cm 3 ·m 2 24h -1 0.1Mpa -1 The results are as follows: (GB / T 1038 standard), tensile strength of 110 MPa, elastic modulus of 1095 MPa (GB / T12914 standard), antibacterial rate > 90% (GB 21551.2 standard), and flame retardancy rating of V-0 (UL-94 standard). This demonstrates that the resulting flame-retardant full heat exchange membrane not only exhibits excellent flame retardancy but also high heat and moisture transfer, gas barrier properties, mechanical properties, and antibacterial purification capabilities.

[0140] like Figure 4 , which is a schematic structural diagram of the porous support membrane of this embodiment, uses a polymer flame retardant, which can be wrapped on the surface of the modified hydrophobic polymer fiber, thereby giving the modified hydrophobic polymer fiber excellent flame retardant properties. Example 3

[0141] The preparation method of the full heat exchange membrane of this embodiment includes: (1) The PP hydrophobic fiber membrane was prepared by dry casting stretching process. The PP hydrophobic fiber membrane had a thickness of 25 μm, a porosity of 50%, and a pore size of 300 nm.

[0142] The specific dry casting and stretching process is a common process in the art and is not specifically limited herein. Alternatively, the PP hydrophobic fiber membrane can be a commercially available PP hydrophobic fiber membrane, as long as the PP hydrophobic fiber membrane meets the requirements of a thickness of 25 μm, a porosity of 50%, and a pore size of 300 nm.

[0143] (2) The PP hydrophobic fiber membrane was immersed in a hydrochloric acid-potassium permanganate system solution and stirred for 10 hours to modify the surface of the PP hydrophobic fiber membrane. The mass ratio of hydrochloric acid to potassium permanganate was 10:90.

[0144] The PP fiber membrane after the immersion treatment was cleaned and dried, and the treated PP fiber membrane was repeatedly cleaned with deionized water until the pH value of the cleaning solution was greater than 6, and the number of cleaning times was 10.

[0145] Aniline monomer is in situ polymerized into polyaniline on the surface of the impregnated PP fiber membrane, wherein ammonium persulfate is used as an initiator for the polymerization of aniline monomer, hydrochloric acid is used as a solvent, wherein the hydrochloric acid concentration is 2M, wherein the polymerization reaction temperature is -4°C, and wherein the polymerization reaction time is 12 hours.

[0146] The polymerization temperature of the in-situ polymerization of aniline on the fiber surface was -4°C, the polymerization time was 10 hours, and the mass ratio of aniline monomer to ammonium persulfate was 50:50.

[0147] (3) Ultrasonic dispersion of the thermal conductive agent in the solvent for 4 hours and 50 immersions. The modified fiber membrane is then repeatedly immersed in the solution to allow the thermal conductive filler to adhere to the modified hydrophobic polymer fiber, thereby obtaining a thermally conductive porous support layer.

[0148] Water-soluble silver nanowires were ultrasonically dispersed in a deionized water solvent to prepare a thermal conductive functional impregnation liquid, wherein the content of the silver nanowires was 10 wt % and the content of the deionized water solvent was 90 wt %.

[0149] The modified PP fiber was repeatedly immersed in the thermal conductive impregnation liquid for a few seconds, and then placed in an oven to dry and remove the solvent, so that the silver nanowire thermal conductive filler was attached to the surface of the PP fiber membrane. The number of immersion-drying cycles was 30.

[0150] (4) dissolving the hydrophilic polymer substrate in deionized water, adding filler, and mixing uniformly by ultrasonication and stirring to obtain a dense layer coating solution; The filler ratio was 15%, the ultrasonic time was 4 hours, and the stirring time was 10 hours.

[0151] Waterborne polyurethane is selected as the hydrophilic polymer matrix, deionized water is used as the solvent, NaCl is selected as the hygroscopic filler, carbon nanotubes are selected as the thermal conductive filler, quaternary ammonium salts are selected as the antibacterial filler, and PEG is selected as the pore-forming filler.

[0152] The mass ratio of polyvinyl alcohol, NaCl, carbon nanotubes, quaternary ammonium salt and PEG is 85:5:5:2:3.

[0153] (5) coating the dense layer coating solution on the surface of the thermally conductive porous support layer and drying it in an oven to obtain the thermally conductive full heat exchange membrane.

[0154] The drying temperature was 70° C., the drying time was 4 hours, and the coating layer thickness was 0.5 μm.

[0155] The coating process includes at least one of calendering, casting, scraping, etc. The present application adopts the scraping process to evenly coat the coating solution on the surface of the modified PP fiber membrane, and places it in an oven to dry to obtain a heat-conducting full heat exchange membrane.

[0156] The test results show that the moisture permeability of the obtained heat-conducting full heat exchange membrane is 3826g / ㎡·24h (GB / T 1037 standard), the thermal conductivity is 1.2W / mK, and the CO2 permeability is 5.0×10 5 cm3 ·m 2 24h -1 0.1Mpa -1 (GB / T 1038 standard), a tensile strength of 131 MPa, and an elastic modulus of 1048 MPa (GB / T12914 standard). This demonstrates that the resulting thermally conductive full heat exchange membrane has excellent heat transfer performance, as well as high-performance moisture permeability, gas barrier properties, and mechanical properties.

[0157] like Figure 5 As shown, this is a schematic diagram of the structure of the porous support membrane of this embodiment. Silver nanowires are selected as thermal conductors. The silver nanowires are composite-modified on the surface of the hydrophobic polymer fibers. The silver nanowires are interconnected to form a network structure, which can give the modified hydrophobic polymer fibers excellent thermal conductivity.

[0158] In the description of the above embodiments, specific features, structures, materials or characteristics may be combined in an appropriate manner in any one or more embodiments or examples.

[0159] The above are only specific embodiments of the present invention, but the scope of protection of the present invention is not limited thereto. Any changes or substitutions that can be easily conceived by a person skilled in the art within the technical scope disclosed in this invention should be included in the scope of protection of the present invention. Therefore, the scope of protection of the present invention should be based on the scope of protection of the claims.

Claims

1. A full heat exchange membrane, characterized in that: The full heat exchange membrane comprises: A porous supporting layer and a functional dense layer coated on the surface of the porous supporting layer; The porous support layer includes modified hydrophobic polymer fibers and a functional agent attached to the surface of the modified hydrophobic polymer fibers; The ratio of the functional agent content to the modified hydrophobic polymer fiber content is X, X is greater than 1% and X is less than 30%; The porosity of the porous support layer is K, K is greater than 30% and K is less than 80%; The functional dense layer comprises a hydrophilic polymer substrate and a filler; the thickness of the functional dense layer is M, M is greater than 0.1 μm and M is less than 2 μm.

2. The total heat exchange membrane according to claim 1, characterized in that The surface density of the hydrophobic polymer fiber is N, which is greater than 5g / m 2 , N is less than 40g / m 2 ; The hydrophobic polymer fiber includes at least one of polyethylene fiber, polypropylene fiber and polyester fiber.

3. The total heat exchange membrane according to claim 1, characterized in that The functional agent includes an antibacterial agent, The antibacterial agent includes one or more of graphene, nanosilver, silver ion compounds, quaternary ammonium salts and titanium dioxide.

4. The total heat exchange membrane according to claim 1, characterized in that The functional agent includes a flame retardant, The flame retardant includes at least one of an inorganic flame retardant and an organic flame retardant. The inorganic flame retardant includes at least one of aluminum hydroxide, aluminum chloride, magnesium oxide, and silicon flame retardants. The organic flame retardant includes at least one of ammonium polyphosphate, antimony polyphosphate, ammonium bromide, and chlorinated polyolefin.

5. The total heat exchange membrane according to claim 1, characterized in that: The functional agent includes a thermal conductive agent, The thermal conductor includes at least one of carbon nanotubes, silver nanowires, graphite, carbon fiber, boron nitride, and aluminum oxide.

6. The total heat exchange membrane according to claim 1, characterized in that The hydrophilic polymer substrate includes one or more of polyvinyl alcohol, polyvinyl pyrrolidone, polyurethane and polyacrylic resin hydrophilic polymers.

7. The total heat exchange membrane according to claim 1, characterized in that: The filler includes a hygroscopic filler, and the hygroscopic filler includes one or more of lithium chloride, calcium chloride, sodium chloride, potassium chloride, carboxymethyl cellulose, chitosan and a metal organic framework compound; The ratio of the hygroscopic filler content to the hydrophilic polymer substrate content is S, and S is greater than 1% and less than 30%.

8. The total heat exchange membrane according to claim 1, characterized in that: The filler comprises a porogenic filler, and the porogenic filler comprises at least one of polyethylene glycol and silica gel; The ratio of the porogenic filler content to the hydrophilic polymer substrate is H, where H is greater than 1% and H is less than 10%.

9. The method for preparing a total heat exchange membrane according to any one of claims 1 to 8, characterized in that: The preparation method of the full heat exchange membrane comprises: (1) Preparation of hydrophobic polymer fibers; (2) Surface modification of the hydrophobic polymer fiber to obtain a modified hydrophobic polymer fiber; (3) attaching the functional agent to the surface of the modified hydrophobic polymer fiber to obtain a porous support layer; (4) dissolving the hydrophilic polymer substrate in a solvent, adding fillers, and mixing uniformly by ultrasonication and stirring to obtain a dense layer coating solution; (5) coating the dense layer coating solution on the surface of the porous support layer and drying it to obtain the full heat exchange membrane.

10. A total heat exchanger, characterized in that: The invention comprises the full heat exchange membrane according to any one of claims 1 to 8.

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