Gas separation composite membrane, vehicle engine system, vehicle air conditioning system, and method for manufacturing a gas separation composite membrane

Abstract

To provide a gas separation composite membrane which is suitable for mounting on a vehicle, has gas selectivity and has excellent gas permeability, an engine system for a vehicle and an air conditioning system for a vehicle which are provided with the same, and a method for producing a gas separation composite membrane.SOLUTION: A gas separation composite membrane includes a gas separation layer, and a porous support supporting the gas separation layer. The gas separation layer has a laminated structure having an intermediate layer having an accumulation part and a non-accumulation part formed on the porous support, and a surface layer formed on the intermediate layer. The surface layer has a filling part which is made to fill the non-accumulation part.SELECTED DRAWING: Figure 2

Description

[Technical Field]

[0001] The present invention relates to a gas separation composite membrane, a vehicle engine system, a vehicle air conditioning system, and a method for manufacturing a gas separation composite membrane. More specifically, it relates to a gas separation composite membrane suitable for installation in a vehicle, having gas selectivity and excellent gas permeability, a vehicle engine system and a vehicle air conditioning system equipped therewith, and a method for manufacturing a gas separation composite membrane. [Background technology]

[0002] Conventionally, gas separation membranes have been proposed that exhibit excellent gas permeability and excellent gas separation selectivity, perform well even when used under high temperature, high pressure, and high humidity conditions, and are less affected by impurities such as toluene present in natural gas (see Patent Document 1). This gas separation membrane has a gas separation layer containing a cross-linked cellulose resin, and has a predetermined linking structure in the cross-linked structure, and the gas separation layer contains a predetermined amount of organic solvent. [Prior art documents] [Patent Documents]

[0003] [Patent Document 1] International Publication No. 2016 / 136294 [Overview of the project] [Problems that the invention aims to solve]

[0004] However, in the gas separation membrane described in Patent Document 1, a gas separation layer containing cross-linked cellulose resin is formed by coating a porous membrane with a solution (doping solution) containing cellulose resin and a cross-linking agent. As a result, some of the doping solution seeps into the voids of the porous membrane. Therefore, the carbon dioxide (CO2) permeability of this gas separation membrane is less than 100 GPU, and from this value, the oxygen (O2) permeability is assumed to be less than 10 GPU. Thus, there was a problem in that high gas permeability could not be achieved.

[0005] The present invention has been made in view of the problems of the prior art, and aims to provide a gas separation composite membrane that is suitable for installation in a vehicle, has gas selectivity and excellent gas permeability, a vehicle engine system and a vehicle air conditioning system equipped therewith, and a method for manufacturing a gas separation composite membrane. [Means for solving the problem]

[0006] The inventors of this invention conducted extensive research to achieve the above objectives and, as a result, discovered that the above objectives can be achieved by combining two specific coating methods in an appropriate order to form a predetermined gas separation layer on a porous support, thereby completing the present invention.

[0007] In other words, the present invention Gas separation composite membrane The device comprises a gas separation layer and a porous support that supports the gas separation layer. Furthermore, the gas separation layer has a laminated structure comprising an intermediate layer having a deposited portion and a non-deposited portion formed on the porous support, and a surface layer formed on the intermediate layer. Furthermore, the surface layer has a filled portion that fills the non-deposited portion. Furthermore, the deposited section, non-deposited section, and packed section all contain the same gas separation layer material.

[0009] Furthermore, the vehicle engine system of the present invention is characterized by comprising the first gas separation composite membrane or the second gas separation composite membrane of the present invention.

[0010] Furthermore, the vehicle air conditioning system of the present invention is characterized by comprising the first gas separation composite membrane or the second gas separation composite membrane of the present invention.

[0011] Furthermore, the method for manufacturing the gas separation composite membrane of the present invention is as described above. no This is a method for manufacturing a gas separation composite membrane. This manufacturing method includes the following first coating step, drying step, and second coating step. The first coating step is a step of coating one surface of a porous support with a coating solution containing a gas separation layer material and an organic solvent. The drying step is a step of removing the organic solvent from the coating solution coated on the porous support by drying. Corresponding to the non-deposited portion in the intermediate layer of the resulting gas separation composite membrane.This is a step of forming a gas separation layer having an unfinished portion on the surface of a porous support. The second coating step is a step of coating a coating liquid containing a gas separation layer material and an organic solvent on the gas separation layer having the unfinished portion. In this manufacturing method, in the first coating step, when coating the coating liquid on the porous support, a first coating means that does not pressurize the coating liquid applied to the porous support Gravure Roll is used. The gravure roll has a circumferential surface in which concave supply sections and embankments are formed alternately. Based on this structure, the coating liquid is supplied, and the unfinished sections are formed during the drying process. Further, in the second coating step, a second coating means is used to pressurize an excessive amount of the coating liquid disposed on at least a part of the gas separation layer having the unfinished portion to coat the coating liquid on the gas separation layer having the unfinished portion and remove the excess coating liquid from the excessive amount of the coating liquid.

Advantages of the Invention

[0012] According to the present invention, by combining two specific coating methods in an appropriate order to form a predetermined gas separation layer on a porous support, etc., it is suitable for mounting on a vehicle, has gas selectivity, and has excellent gas permeability. A gas separation composite membrane, a vehicle engine system and a vehicle air conditioning system provided with the same, and a method for manufacturing a gas separation composite membrane can be provided.

Brief Description of the Drawings

[0013] [Figure 1] It is a perspective view schematically showing an embodiment of a first gas separation composite membrane of the present invention. [Figure 2] It is a cross-sectional view of the gas separation composite membrane shown in FIG. 1 cut along line II-II. [Figure 3] It is a cross-sectional view showing an embodiment of a second gas separation composite membrane of the present invention. [Figure 4] It is an explanatory view schematically showing an embodiment of a method for manufacturing a first or second gas separation composite membrane of the present invention. [Figure 5] It is an explanatory view schematically showing a main part of an embodiment of a vehicle engine system of the present invention. [Figure 6] It is an explanatory view schematically showing a main part of an embodiment of a vehicle air conditioning system of the present invention. [Figure 7]This is a schematic diagram illustrating a stainless steel gas separation composite membrane module used for evaluating gas separation composite membranes. [Modes for carrying out the invention]

[0014] The gas separation composite membrane, vehicle engine system, vehicle air conditioning system, and method for manufacturing the gas separation composite membrane of the present invention will be described in detail below with reference to the drawings. Note that the dimensional ratios in the drawings cited below are exaggerated for illustrative purposes and may differ from actual ratios.

[0015] [First gas separation composite membrane] As shown in Figure 1, a gas separation composite membrane 1, which is one embodiment of the first gas separation composite membrane of the present invention, comprises a gas separation layer 10 and a porous support 20 that supports the gas separation layer 10. More specifically, as shown in Figure 2, the gas separation layer 10 has a laminated structure comprising an intermediate layer 11 having deposited portions 111 and non-deposited portions 113 alternately formed laterally on the porous support 20, and a surface layer 13 formed on the intermediate layer 11. Furthermore, the surface layer 13 has filled portions 131 that fill the non-deposited portions 113. Note that the illustrated example typically shows a case where the material or composition of the material forming the intermediate layer 11 and the material or composition of the material forming the surface layer 13 are different.

[0016] Here, the gas separation layer 10 is a layer that separates a gas containing one or more components from a mixed gas containing two or more components. The gas separation layer can be applied, for example, as a layer that separates O2 from air containing O2 and N2, or as a layer that separates CO2 or water vapor (H2O) from air containing CO2 or water vapor (H2O).

[0017] Furthermore, in the gas separation composite membrane of the present invention, the structure of the porous support 20 is not particularly limited, as long as it supports the gas separation layer 10 and ensures the permeability of the gas separated in the gas separation layer 10. In the gas separation composite membrane 1 of this embodiment, the porous support 20 ensures the gas permeability of the porous support 20 by forming elongated holes in which each of the plurality of pores 20A directly communicates the surface 20B on the gas separation layer 10 side and the back surface 20C on the opposite side (see Figure 2).

[0018] Although not shown in the figures, in the gas separation composite membrane of the present invention, for example, the gas permeability of the porous support 20 can also be ensured by having a porous support 20 having a plurality of pores 20A, where the pores 20A communicate with other pores 20A, and have a large number of branching and merging parts, or are winding, thereby forming communication holes that connect the surface 20B and the back surface 20C.

[0019] Next, the advantages of this embodiment will be described. In the gas separation composite membrane 1 of this embodiment, the surface layer 13 is formed such that the filling portion 131 fills the non-deposited portion 113 that is intentionally or inevitably formed in the intermediate layer 11 when the gas separation layer 10 is formed thinly on the porous support 20. This is thought to enable good vehicle mountability, gas selectivity, and excellent gas permeability. In particular, it is preferable that the gas separation layer 10 is not formed in a state in which it has entered the pores 20A of the porous support 20, in other words, it is preferable that only the material forming the porous support 20 exists inside the porous support 20.

[0020] The following describes the materials and other components of the gas separation composite membrane in this embodiment.

[0021] (Gas separation layer) Examples of materials that can form the gas separation layer 10 include organic polymer materials such as polymers of intrinsic microporosity (PIM), polytrimethylsilylpropyne (PTMSP), polyimide, and silicone. These can be used individually or in combination of two or more. Among these, it is preferable to use polyimides such as aromatic polyimides and fluorine-containing polyimides, and polyimides of intrinsic microporosity such as PIM-1, with PIM-1 being more preferable. PIM-1 has, for example, a constituent unit represented by the following formula (I).

[0022] [ka]

[0023] In equation (I) above, R 1 R is a hydrogen atom or a linear or branched alkyl group having 1 to 4 carbon atoms. 2 R is a hydrogen atom, a linear or branched alkyl group having 1 to 4 carbon atoms, or a cyano group. 3 R is a hydrogen atom, a linear or branched alkyl group having 1 to 4 carbon atoms, or a cyano group. Multiple R in the same structural unit. 1 , R 2 and R 3 These may be the same or different.

[0024] As shown in formula (I), PIM-1 is a polymer that has a rigid ladder-like structure and a bent skeleton, and can form micropores within its layers. Therefore, the gas separation layer 10 containing PIM-1 has excellent gas permeability.

[0025] As materials for forming the gas separation layer 10, composite materials can be obtained by further including particles with a particle size of 1 nm to 20 nm in addition to the various organic polymer materials mentioned above. Suitable materials for forming such particles include inorganic materials, typically silica and ceramic materials such as zeolites. Various particles produced and marketed by known manufacturing methods can be used as such particles, but in the case of silica particles, examples include (1) fumed silica nanoparticles synthesized by a gas-phase method (dry method) in which silicon-containing raw materials such as silicon tetrachloride are burned in an oxygen and hydrogen flame to hydrolyze them, and (2) colloidal silica nanoparticles synthesized by a liquid-phase method (wet method) such as the water glass method in which sodium is removed by ion exchange of sodium silicate and then heated and aged, or the alkoxide hydrolysis method in which alkoxides such as tetraethoxysilane are hydrolyzed and polycondensed in an alcohol solvent.

[0026] From the viewpoint of forming a gas separation layer 10 with superior gas permeability and gas selectivity by forming fine pores between the particles as described above, or between the particles and the organic polymer material, the particle diameter is preferably 1 nm to 20 nm, more preferably 1 nm to 10 nm, and even more preferably 1 nm to 5 nm.

[0027] In the present invention, the particle size of the above-mentioned particles can be measured and calculated in the following manner. First, the gas separation composite membrane is cut along its thickness at an arbitrary position on the membrane. Next, the obtained cut surface is observed using a scanning electron microscope (SEM) or a transmission electron microscope (TEM), and if necessary, further observed using energy-dispersive X-ray analysis (EDS) or X-ray photoelectron spectroscopy (XPS). For four particles, the distance between any two points on the contour line is measured, and the maximum distance is determined. After that, the average of the maximum distances of the four particles is calculated and taken as the particle size of the particle.

[0028] From the viewpoint of forming a gas separation layer 10 with excellent gas permeability and gas selectivity by forming fine pores between particles having sterically hindrance-causing modifying groups and an organic polymer material, it is preferable that the particles have modifying groups on their surface. Such particles having modifying groups can be obtained, for example, by surface-modifying the particles with a silane coupling agent.

[0029] From the viewpoint of improving gas permeability and gas selectivity, the gas separation layer 10 preferably contains an organic polymer material and the aforementioned particles. From the viewpoint of improving gas permeability and gas selectivity, the content ratio of the aforementioned particles in the gas separation layer 10 is preferably 10% by mass or more and 80% by mass or less, and more preferably 20% by mass or more and 60% by mass or less.

[0030] In this invention, the particle content in the gas separation layer can be measured and calculated in the following manner. First, a fixed amount (1 g) of the gas separation layer is taken and its mass is measured. Next, the organic polymer material is removed from the gas separation layer by combustion or the like, and the mass of the remaining particles is measured. After that, the ratio of the mass of the particles to the mass of the gas separation layer is calculated to determine the particle content in the gas separation layer.

[0031] From the viewpoint of improving gas permeability, the thickness of the gas separation layer 10 is preferably 500 nm or less, and more preferably 400 nm or less. Furthermore, from the viewpoint of the mechanical strength of the gas separation layer, the thickness of the gas separation layer 10 is preferably 5 nm or more, and more preferably 10 nm or more.

[0032] In the present invention, the thickness of the gas separation layer is the distance from the surface (part) of the porous support 20's surface 20B that is in contact with the portion where the pores 20A are not open, to the surface 10A of the gas separation layer 10 (see Figure 2).

[0033] In the present invention, the thickness of the gas separation layer can be measured and calculated in the following manner. First, the gas separation composite membrane is cut along its thickness at an arbitrary position on the membrane. Next, the resulting cut surface is observed using SEM or TEM, and if necessary, further observed using EDS, XPS, or FT-IR, and the distance from the portion of the porous support surface that is in contact with the portion where the pores are not open to the surface of the gas separation layer is measured at four locations. After that, the average value of these four distances is calculated and given as the thickness of the gas separation layer.

[0034] (Porous support) The material forming the porous support 20 may be either an organic or an inorganic material, but an organic material is preferred. Examples of organic materials include various resin materials such as polytetrafluoroethylene (PTFE), polyethylene (PE), and polypropylene (PP). These can be used individually or in combination of two or more. Suitable materials for forming the porous support 20 include PTFE and PP.

[0035] From the viewpoint of providing mechanical strength and high gas permeability, the thickness of the porous support 20 is preferably 1 μm to 3000 μm, more preferably 5 μm to 500 μm, and even more preferably 5 μm to 150 μm.

[0036] In the present invention, the thickness of the porous support can be measured and calculated in the following manner. First, the gas separation composite membrane is cut along the thickness direction at an arbitrary position on the gas separation composite membrane. Next, the obtained cut surface is observed using SEM or TEM, and if necessary, further observed using EDS, XPS, or FT-IR, and the distance from the surface 20B to the back surface 20C of the porous support 20 is measured at four locations. After that, the average value of these four distances is calculated and given as the thickness of the porous support.

[0037] In the porous support 20, there are no particular limitations as long as the porous support 20 has sufficient gas permeability, but it is preferable that the porous support contains pores with a pore size, typically an average pore diameter of 0.01 μm or more and 0.5 μm or less, and that the porosity of the porous support 20 is 40% or more and 80% or less.

[0038] In this invention, the average pore diameter can be measured and calculated in the following manner: Depending on whether the pore shape of the porous support is elongated or interconnected, the surface or cross-section of the porous support is observed using an SEM or TEM, and the maximum distance between any two points on the contour line of the pores (observation surface) of the porous support is measured. Then, the average value of the pores observed within several to tens of fields of view is calculated and used as the average pore diameter.

[0039] In this invention, porosity can be measured using a general immersion method. Alternatively, one method involves determining the total volume from the weight and bulk density of the porous support, calculating the pore volume from the difference between this value and the actual volume, and then calculating the porosity. Another method involves impregnating the porous support with a solvent such as ethanol or water, converting the weight of the impregnated ethanol to a volume, and using this as the pore volume to determine the porosity.

[0040] [Second gas separation composite membrane] In the following embodiments, the same reference numerals are used for the same components as in the embodiment of the first gas separation composite membrane described above, and detailed descriptions are omitted. Figure 3 is a cross-sectional view of an embodiment of the second gas separation composite membrane of the present invention, cut along the same line as II-II shown in Figure 1. The schematic perspective view of an embodiment of the second gas separation composite membrane of the present invention is the same as that shown in Figure 1.

[0041] As shown in Figure 3, the gas separation composite membrane 2, which is one embodiment of the second gas separation composite membrane of the present invention, corresponds to the gas separation composite membrane 1 described above, in which the material and composition of the material forming the intermediate layer 11 and the material forming the surface layer 13 are typically the same. Specifically, the gas separation composite membrane 2 of this embodiment does not have a laminated structure in which the gas separation layer 10 comprises the intermediate layer 11 and the surface layer 13 described above as an essential component, and although not shown, it has the same configuration as the gas separation composite membrane 1, which is one embodiment of the first gas separation composite membrane of the present invention, except that it has the following structural and characteristic (1) to (3) as essential components.

[0042] (1) The thickness of the gas separation layer 10 is 500 nm or less. (2) The O2 permeability of the gas separation layer 10 is 100 GPU or more. (3) The O2 / N2 selectivity of the gas separation layer 10 is 1.20 or higher.

[0043] Next, the advantages of this embodiment will be described. The gas separation composite membrane 2 of this embodiment can achieve good vehicle mountability, gas selectivity, and excellent gas permeability. In particular, in order to form a gas separation layer with the desired performance, the selection of a coating solution containing the material that forms the gas separation layer and the organic solvent described in more detail later is important. From the viewpoint of easily improving gas selectivity and gas permeability, it is preferable that the material and composition of the material forming the intermediate layer 11 and the material and composition of the material forming the surface layer 13 are the same, and it is also preferable that the organic solvent used together with them is the same.

[0044] The structure and characteristics of the components of the gas separation composite membrane in this embodiment will be described below.

[0045] In the gas separation composite membrane 2 of this embodiment, from the viewpoint of improving gas permeability, it is preferable that the thickness of the gas separation layer 10 is 400 nm or less. Furthermore, in the gas separation composite membrane 2 of this embodiment, from the viewpoint of the mechanical strength of the gas separation layer, it is preferable that the thickness of the gas separation layer 10 is 5 nm or more, and more preferable that it is 10 nm or more.

[0046] In the gas separation composite membrane 2 of this embodiment, the O2 permeability of the gas separation layer 10 is preferably 300 GPU or more, more preferably 1000 GPU or more, and even more preferably 4000 GPU or more. Furthermore, in the gas separation composite membrane 2 of this embodiment, from the viewpoint of improving gas selectivity, the O2 permeability of the gas separation layer 10 is preferably 9000 GPU or less, and more preferably 7000 GPU or less.

[0047] In the gas separation composite membrane 2 of this embodiment, the O2 / N2 selectivity of the gas separation layer 10 is preferably 1.25 or higher, more preferably 1.30 or higher, and even more preferably 1.50 or higher. Furthermore, in the gas separation composite membrane 2 of this embodiment, from the viewpoint of improving gas permeability, the O2 / N2 selectivity of the gas separation layer 10 is preferably 2.00 or lower.

[0048] [Method for manufacturing gas separation composite membranes] As shown in Figure 4, one embodiment of the method for manufacturing a gas separation composite membrane of the present invention is an example of a method for manufacturing the first or second gas separation composite membrane described above, and includes the following first coating step, first drying step, second coating step, and second drying step.

[0049] As shown in Figure 4(A), the first coating step is to coat one surface 20B of the porous support 20 with a coating liquid 31. In this first coating step, a first coating means 41 is used that does not pressurize the coating liquid 31 applied to the porous support 20 when applying the coating liquid 31 to the porous support 20. This coating liquid 31 contains a gas separation layer material (not shown) and an organic solvent.

[0050] In this invention, "coating" means the time when the coating liquid is actually being applied, or the time from after the coating liquid has been applied to the porous support until the coating liquid applied to the porous support has dried to the extent that it no longer penetrates the porous support.

[0051] In the coating solution 31 described above, the above-mentioned organic polymer material and the above-mentioned particles, which may be added as needed, can be used as the gas separation layer material.

[0052] Furthermore, in the coating solution 31 described above, for example, tetrahydrofuran, chloroform, dichloromethane, N-methyl-2-pyrrolidone, toluene, isopropyl alcohol, and tetralin can be used as the organic solvent. These can be used individually or in combination of two or more. For example, as an organic solvent to be applied to PIM-1 or polyimide, tetrahydrofuran (THF) is preferred from the viewpoint of high solubility of PIM-1 and polyimide.

[0053] Furthermore, as the first coating means 41, for example, a gravure roll of a gravure coater that rotates in the direction indicated by arrow Z, as shown in Figure 4(A), can be used. At this time, the porous support 20 to be coated is also supplied in the direction indicated by arrow Y at the same feed rate as the rotation speed of the gravure roll 41. Although not shown, in the present invention, a die coater can also be used as the first coating means 41.

[0054] As shown in Figure 4(B), the first drying step is to remove the organic solvent from the coating liquid 31 applied to the porous support 20 by drying, and to form a gas separation layer 10 having an incomplete portion 33 on the surface 20B of the porous support 20. Here, the incomplete portion 33 is typically a permeable non-deposited portion 113, and the gas separation layer 10 is typically a deposited portion 111. In this drying step, it is sufficient to form a gas separation layer 10 (deposited portion 111) having an intentionally or inevitably formed incomplete portion 33 (non-deposited portion 113) on the surface 20B of the porous support 20. In this first drying step, for example, drying in an atmospheric environment at a temperature of 10°C to 40°C for 1 to 8 hours.

[0055] As shown in Figure 4(C), the second coating step is to coat the gas separation layer 10 (accumulation section 111) having an incomplete section 33 (non-accumulation section 113) with the coating liquid 31. In this second coating step, a second coating means 43 is used to pressurize an excess amount of coating liquid that is placed in at least a part of the gas separation layer 10 (accumulation section 111) having an incomplete section 33 (non-accumulation section 113) with the coating liquid 31, and to coat the gas separation layer 10 (accumulation section 111) having an incomplete section 33 (non-accumulation section 113) with the coating liquid 31, while also removing the excess amount of coating liquid from the excess amount of coating liquid.

[0056] The coating liquid 31 in the second coating step may be the same as the coating liquid 31 in the first coating step in terms of components and composition, or it may be a different coating liquid. Furthermore, as the second coating means 43, for example, a bar coater that moves in the direction indicated by arrow X, as shown in Figure 4(C), can be used.

[0057] As shown in Figure 4(D), the second drying step is a step in which the organic solvent is removed by drying from the coating liquid 31 applied to the gas separation layer 10 (deposited portion 111) having an incomplete portion 33 (non-deposited portion 113), and the gas separation layer 10 is formed on the surface 20B of the porous support 20 to obtain a gas separation composite membrane.

[0058] Next, the advantages of this embodiment will be described. According to the method for manufacturing a gas separation composite membrane of this embodiment, a gas separation layer 10 (deposited portion 111) is formed having an incomplete portion 33 (non-deposited portion 113) that is intentionally or inevitably formed. Furthermore, by coating the incomplete portion 33 (non-deposited portion 113) with a coating liquid 31, the penetration of the coating liquid into the porous support is suppressed or prevented. As a result, a gas separation composite membrane suitable for mounting on a vehicle can be obtained, which has gas selectivity and excellent gas permeability.

[0059] In the method for manufacturing the gas separation composite membrane of the present embodiment, the proportion of the concave supply part (cell) 411 of the coating liquid 31 on the peripheral surface 41A in which the concave supply part (cell) 411 of the gravure roll 41 as the first coating means 41 and the bank 413 are alternately formed is 80% or more and 99% or less, preferably 85% or more and 99% or less, more preferably 85% or more and 90% or less, and the liquid volume of the coating liquid 31 in the concave supply part (cell) 411 is 4.7 cm 3 / m 2 or more and 28.3 cm 3 / m 2 or less (see Fig. 4(A)).

[0060] In addition, Wc in Fig. 4(A) indicates the cell width, Wb indicates the bank width, and Cc indicates the cell period. The proportion of the concave supply part (cell) is calculated by (cell width (Wb)) / (cell width (Wb) + bank width (Wb)) × 100. By adopting such a manufacturing method, the above-mentioned gas separation composite membrane having more excellent gas selectivity and gas permeability can be produced with good yield.

[0061] The gas separation membrane module to which the above-mentioned gas separation composite membrane is applied can separate a predetermined gas from a mixed gas and increase or decrease the gas concentration of the predetermined gas. Furthermore, the above-mentioned gas separation composite membrane has excellent gas permeability together with good vehicle-mountability and gas selectivity. Therefore, such a gas separation membrane module can be suitably used, for example, in a vehicle engine system or a vehicle air-conditioning system.

[0062] [Vehicle engine system] Nitrogen oxides (NOx) in the exhaust gas are generated by the reaction of N2 and O2 in the combustion air mixed with the fuel at a high temperature, and the higher the O2 concentration in the combustion region, the more NOx is generated. By applying a gas separation membrane module to the intake system of a vehicle engine system, it is possible to reduce the O2 concentration and burn the fuel using nitrogen-enriched air with a relatively high N2 concentration. As a result, the O2 concentration in the combustion region is lowered, and NOx in the exhaust gas can be reduced.

[0063] Figure 5 shows one embodiment of the vehicle engine system of the present invention. The vehicle engine system 50 includes a gas separation membrane module 52 provided in the intake system passage of the engine 51. This gas separation membrane module 52 includes the gas separation membranes 1 and 2 described above. As shown in Figure 5, when air is supplied to the gas separation membrane module 52, it is separated into nitrogen-enriched air and oxygen-containing gas by the gas separation membranes 1 and 2. When this nitrogen-enriched air is supplied to the engine 51, a fuel (not shown) can be burned in a lean state in the engine 51, and NOx in the exhaust from the engine 51 can be reduced.

[0064] [Vehicle air conditioning system] In a vehicle cabin, the presence of the driver and passengers causes the O2 concentration in the cabin air to gradually decrease, while the CO2 and water vapor (H2O) concentrations gradually increase. By applying a gas separation membrane module to the vehicle's air conditioning system, the O2 concentration can be increased while the CO2 and water vapor (H2O) concentrations can be reduced. As a result, the air composition inside the vehicle cabin can be appropriately modified with a simple configuration.

[0065] Figure 6 shows one embodiment of the vehicle air conditioning system of the present invention. The vehicle air conditioning system 60 comprises gas separation membrane modules 62, 62 installed in the duct of the passenger compartment 61. These gas separation membrane modules 62, 62 are equipped with the gas separation membranes 1, 2 described above. Inside air from the passenger compartment 61 circulates through the duct of the passenger compartment 61 to one side of the gas separation membrane modules 62, 62, while outside air is drawn in and exhausted through another duct to the other side of the gas separation membrane modules 62, 62. As shown in Figure 6, when inside air and outside air are supplied to the gas separation membrane modules 62, 62, O2 is separated from the outside air and CO2 and water vapor (H2O) are separated from the inside air by the gas separation membranes 1, 2, thereby increasing the O2 concentration in the inside air and decreasing the CO2 concentration and water vapor (H2O) concentration, making it possible to maintain a constant air composition inside the passenger compartment with a simple configuration. [Examples]

[0066] The present invention will be described in more detail below with reference to several examples, but the present invention is not limited to these examples. Unless otherwise specified, each example and comparative example was carried out under atmospheric pressure, at room temperature (25°C) and relative humidity of 50% RH.

[0067] (Example 1) In the first coating step, the porous support (material: PTFE, thickness: 500 μm, pore size: 0.1 μm, porosity: 60%) is coated with the first coating liquid (gas separation layer material (material; PIM-1 (R in formula (I)) 1 is a methyl group, R 2 R is a cyano group. 3 (This is a hydrogen atom.), weight-average molecular weight (Mw) = 3.1 × 10⁻¹⁴ 5 A first gravure coater equipped with a gravure roll (plate / lines per inch: 200 L / inch, cell period: 127 μm, cell width: 113 μm, ridge width: 14 μm, cell abundance: 89%, coating liquid volume: 7.5 cm³) uses organic solvent (material: THF) and organic polymer material concentration: 4% by mass. 3 / m 2 The surface was coated using ).

[0068] Next, the mixture was dried in a fume hood at room temperature (25°C) for 4 hours to remove the organic solvent from the first coating solution applied to the porous support, forming a gas separation layer with incomplete portions on the surface of the porous support.

[0069] Furthermore, in the second coating process, the first coating solution was applied to the gas separation layer, which had incomplete sections, using a bar coater.

[0070] Subsequently, the mixture was dried in a fume hood at room temperature (25°C) for 4 hours to remove the organic solvent from the first coating solution applied to the gas separation layer, which still had an incomplete portion, thereby forming the gas separation layer and obtaining the gas separation composite membrane of this example.

[0071] (Example 2) The above first coating liquid is used as the second coating liquid (gas separation layer material (material; PIM-1 (R in formula (I)) 1 is a methyl group, R 2R is a cyano group. 3 (This is a hydrogen atom.), weight-average molecular weight (Mw) = 3.1 × 10⁻¹⁴ 5 Except for replacing the weight-average molecular weight (Mw) / number-average molecular weight (Mn) with particles (material: silica, particle size: 5 nm, surface modification group: vinyl group), PIM-1: silica particles = 40 parts by mass: 60 parts by mass, organic solvent (material: THF), concentration of organic polymer material: 4% by mass, concentration of silica particles: 40% by mass), the same procedure as in Example 1 was repeated to obtain the gas separation composite membrane of this example.

[0072] (Example 3) The gas separation composite membrane of this example was obtained by repeating the same procedure as in Example 1, except that the above porous support was replaced with a porous support (material: PTFE, thickness: 500 μm, pore size: 0.05 μm, porosity: 60%), and the first gravure coater in the first coating step was replaced with a die coater.

[0073] (Example 4) The gas separation composite membrane of this example was obtained by repeating the same procedure as in Example 1, except that the above porous support was replaced with a porous support (material: PP, thickness: 500 μm, pore size: 0.1 μm, porosity: 60%), and the above first gravure coater was replaced with a die coater.

[0074] (Example 5) The above first coating liquid is used as the third coating liquid (gas separation layer material (material; polyimide (6FDA-3MPA, number average molecular weight (Mn) 2.5 × 10) 5 The gas separation composite membrane of this example was obtained by repeating the same procedure as in Example 1, except that the weight-average molecular weight (Mw) / number-average molecular weight (Mn) = 1.7, the organic solvent (material: THF), and the concentration of the organic polymer material: 4% by mass.

[0075] (Example 6) In the first coating process described above, the first gravure coater is replaced with a second gravure coater equipped with a gravure roll (plate / line count: 100 L / inch, cell period: 254 μm, cell width: 221 μm, ridge width: 33 μm, cell presence ratio: 87%, coating liquid volume: 17.3 cm3 / m 2 The gas separation composite membrane of this example was obtained by repeating the same procedure as in Example 1, except that a different component was used.

[0076] (Example 7) In the above first coating process, the above first gravure coater is replaced with a third gravure coater equipped with a gravure roll (plate / line count: 150 L / inch, cell period: 169 μm, cell width: 137 μm, ridge width: 32 μm, cell presence ratio: 81%, coating liquid volume: 15.7 cm 3 / m 2 The gas separation composite membrane of this example was obtained by repeating the same procedure as in Example 1, except that a different component was used.

[0077] (Example 8) In the above first coating process, the above first gravure coater is replaced with a fourth gravure coater equipped with a gravure roll (plate / line count: 300 L / inch, cell period: 85 μm, cell width: 70 μm, ridge width: 15 μm, cell presence ratio: 82%, coating liquid volume: 4.7 cm 3 / m 2 The gas separation composite membrane of this example was obtained by repeating the same procedure as in Example 1, except that a different component was used.

[0078] (Comparative Example 1) The gas separation composite film of this example was obtained by repeating the same procedure as in Example 1, except that the first gravure coater was replaced with the bar coater in the first coating process described above.

[0079] (Comparative Example 2) The gas separation composite film of this example was obtained by repeating the same procedure as in Example 1, except that the first gravure coater was replaced with the bar coater in the first coating step, and the bar coater was replaced with the first gravure coater in the second coating step.

[0080] (Comparative Example 3) The gas separation composite membrane of this example was obtained by repeating the same procedure as in Example 1, except that the first coating solution was replaced with the second coating solution and the bar coater in the second coating step was replaced with the first gravure coater.

[0081] (Comparative Example 4) The gas separation composite membrane of this example was obtained by repeating the same procedure as in Example 1, except that the first coating solution was replaced with the third coating solution and the first gravure coater in the first coating step was replaced with the bar coater. Some of the specifications of each of the above examples are shown in Tables 1 and 2.

[0082] [Table 1]

[0083] [Table 2]

[0084] The "gas separation layer thickness" in Tables 1 and 2 was measured and calculated as follows: First, the gas separation composite membrane was cut along its thickness at an arbitrary position. Next, the resulting cross-section was observed using SEM or TEM, and if necessary, further observed using EDS, XPS, or FT-IR. The distance from the portion of the porous support surface that was in contact with a non-porous portion to the surface of the gas separation layer was measured at four locations. The average of these four distances was then calculated and used as the thickness of the gas separation layer.

[0085] The "O2 permeability" and "O2 / N2 selectivity" in Tables 1 and 2 were measured and calculated as follows. Specifically, the gas separation composite membrane was evaluated using the stainless steel gas separation membrane module 71 shown in Figures 7(A) and (B). More specifically, as shown in Figure 7(A), a sample 73 cut from the gas separation composite membranes prepared in the examples and comparative examples was fixed between the gas supply side 75 and the permeate side 77 of the gas separation membrane module 71. Then, as shown in Figure 7(A), the inlet 75A of the gas supply side 75 was closed, and the outlet 77A of the permeate side 77 was connected to a vacuum device to create a vacuum inside the gas separation membrane module 71. Subsequently, as shown in Figure 7(B), a predetermined amount of gas (N2, O2, and a mixture thereof) was supplied from the inlet 75A to the supply side 75. The time until the pressure difference with the permeate side 77 disappeared (with the inlet 75A and outlet 77A closed after gas supply) was measured to calculate the permeation rate and permeability (permeation coefficient) of N2 and O2. Selectivity (unitless (-)) was calculated from selectivity = (permeability coefficient of O2) / (permeability coefficient of N2), and the permeability coefficient of the gas was calculated as permeability (unit (GPU): 1 GPU = 3.35 × 10⁻¹⁵ -10 mol·m -2 ·s -1 ·Pa -1 )

[0086] The gas mixture had the same composition as ordinary air, with N2 at 79% by volume and O2 at 21% by volume. The pressure (or pressure difference) between the supply side and the permeate side was continuously measured using pressure gauges installed inside the supply side 55 and the permeate side 57. Furthermore, the internal pressure used to determine a vacuum was 0.1 MPa (or less).

[0087] More specifically, the transmission rate and permeability (transmission coefficient) of N2 and O2, and the selectivity based on these, were calculated using the following equations (1) to (3).

[0088] The pressure difference on the permeating side over time can be calculated using the following equation (1). Pressure difference: dP / dt=(Pe-Ps) / t (1) Here, in equation (1), Pe represents the pressure at which 0 kPa is reached on the permeation side, Ps represents the pressure at the start of measurement on the permeation side, and t represents the time to reach 0 kPa.

[0089] The gas permeation rate can be determined by the following equation (2). Transmission rate: q=V / RT dP / dt (2) Here, in equation (2), V is the permeate volume, R is the molar gas constant, T is the absolute temperature during the experiment, and dP / dt is the pressure difference obtained in equation (1). The temperature during the experiment was 25°C.

[0090] The transmittance coefficient can be calculated using the following formula (3). Transmission coefficient: P / δ=q / Ph / A (3) Here, in equation (3), q is the permeation rate, Ph is the pressure when the gas is supplied on the supply side, A is the effective area of ​​the gas separation layer, P is the permeation coefficient (Pa), and δ is the thickness of the gas separation layer (μm).

[0091] Tables 1 and 2 show that Examples 1 to 8, which fall within the scope of the present invention, have superior gas permeability and gas selectivity compared to Comparative Examples 1 to 4, which fall outside the scope of the present invention. Specifically, the O2 permeability of Examples 1 to 8 is more than 10 times better than the O2 permeability assumed for the gas separation membrane in Patent Document 1 (less than 10 GPU). In particular, the O2 permeability of Examples 1, 2, and 6 to 8 is more than 100 times better than the O2 permeability assumed for the gas separation membrane in Patent Document 1 (less than 10 GPU). Furthermore, since the gas separation composite membrane is equipped with a porous support that supports the gas separation layer, it is suitable for installation in vehicles.

[0092] In the gas separation composite membrane of the present invention, the above-described effects are considered to have been obtained because a gas separation layer having the above-described structure or structure and characteristics was formed on a porous support by combining two specific coating methods in an appropriate order.

[0093] Furthermore, as can be seen from Tables 1 and 2, it is believed that the above-mentioned effects were obtained because a gas separation layer containing the aforementioned organic polymer material was formed on the porous support.

[0094] Furthermore, as shown in Table 1, it is believed that the above-mentioned effects were obtained because a gas separation layer containing the aforementioned particles was formed on the porous support.

[0095] Furthermore, Tables 1 and 2 suggest that the above-mentioned effects were obtained because the porous support described above was used.

[0096] Furthermore, as can be seen from Table 2, it is considered that the above-mentioned effects were obtained because the gravure roll described above was used in the first coating process.

[0097] At present, Example 1 appears to yield the best results in terms of excellent gas permeability and gas selectivity.

[0098] Although the present invention has been described above with reference to some embodiments and examples, the present invention is not limited thereto, and various modifications are possible within the scope of the gist of the present invention. [Explanation of Symbols]

[0099] 1, 2: Gas separation composite membrane, 10: Gas separation layer, 10A: Surface, 11: Intermediate layer, 111: Deposited section, 113: Non-deposited section, 13: Surface layer, 131: Filled section, 20: Porous support, 20A: Pores, 20B: Surface, 20C: Back surface, 31: Coating liquid, 33: Unfinished section, 41: First coating means (gravure roll), 41A: Peripheral surface, 411: Concave supply section (cell): 413: Embankment, 43: Second Coating means (bar coater), 50: Vehicle engine system, 51: Engine, 52: Gas separation membrane module, 60: Vehicle air conditioning system, 61: Passenger compartment, 62: Gas separation membrane module, 71: Stainless steel gas separation membrane module, 73: Sample of gas separation composite membrane, 75: Gas supply side, 75A: Inlet of gas supply side, 77: Gas permeate side, 77A: Outlet of gas permeate side

Claims

1. A gas separation composite membrane comprising a gas separation layer and a porous support that supports the gas separation layer, The gas separation layer has a laminated structure comprising an intermediate layer having a deposited portion and a non-deposited portion formed on the porous support, and a surface layer formed on the intermediate layer. The surface layer has a filling portion that is filled in the non-deposited portion, The aforementioned deposition section and the aforementioned filling section contain the same gas separation layer material. A gas separation composite membrane characterized by the following:

2. The gas separation layer is given by the following equation (I) 【Chemistry 1】 A gas separation composite membrane according to claim 1, characterized by comprising at least one selected from the group consisting of a unique microporous polymer having a structural unit represented by formula (I), polytrimethylsilylpropyne, polyimide, and silicone. (In formula (I), R1 is a hydrogen atom or a linear or branched alkyl group having 1 to 4 carbon atoms; R2 is a hydrogen atom, a linear or branched alkyl group having 1 to 4 carbon atoms, or a cyano group; R3 is a hydrogen atom, a linear or branched alkyl group having 1 to 4 carbon atoms, or a cyano group. Multiple R1, R2, and R3 in the same structural unit may be the same or different.)

3. The gas separation composite membrane according to claim 1 or 2, characterized in that the gas separation layer contains particles having a particle size of 1 nm or more and 20 nm or less.

4. The gas separation composite membrane according to any one of claims 1 to 3, characterized in that the porous support comprises at least one selected from the group consisting of polytetrafluoroethylene, polyethylene, and polypropylene.

5. The porous support comprises pores with a pore diameter of 0.01 μm or more and 0.5 μm or less. The porosity of the porous support is 40% or more and 80% or less. A gas separation composite membrane according to any one of claims 1 to 4.

6. A vehicle engine system characterized by comprising a gas separation composite membrane according to any one of claims 1 to 5.

7. A vehicle air conditioning system characterized by comprising a gas separation composite membrane according to any one of claims 1 to 5.

8. A method for manufacturing a gas separation composite membrane according to any one of claims 1 to 5, A first coating step involves applying a coating solution containing a gas separation layer material and an organic solvent to one surface of the porous support, A drying step is performed to remove the organic solvent from the coating liquid applied to the porous support by drying, thereby forming a gas separation layer on the surface of the porous support having an incomplete portion corresponding to the non-deposited portion in the intermediate layer of the resulting gas separation composite membrane. The process includes a second coating step of applying a coating liquid containing a gas separation layer material and an organic solvent onto the gas separation layer having the incomplete portion, In the first coating step, when applying the coating liquid to the porous support, a gravure roll is used as the first coating means that does not pressurize the coating liquid applied to the porous support. The gravure roll has a circumferential surface in which concave supply sections and embankments are alternately formed, and the coating liquid is supplied based on this structure, and the unfinished section is formed during the drying process. In the second coating step, a second coating means is used to apply the coating liquid to the gas separation layer having the incomplete portion by pressurizing an excess amount of coating liquid that is placed in at least a part of the gas separation layer having the incomplete portion, and to remove the excess amount of coating liquid from the excess amount of coating liquid. A method for producing a gas separation composite membrane, characterized by the above.

9. The first coating means is a gravure roll, The proportion of the concave supply portion of the coating liquid on the circumferential surface of the gravure roll is 80% or more. The amount of the coating liquid in the concave supply section is 4.7 cm. ３ / m ２ 28.3cm or more ３ / m ２ The following is The method for producing a gas separation composite membrane according to feature 8.

10. The method for producing a gas separation composite membrane according to claim 9, characterized in that the proportion of the concave supply portion is 85% or more.

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