Substrate with particles and method for producing substrate with particles

Abstract

The present disclosure provides a particle-bearing substrate having: a fibrous substrate comprising inorganic fibers; an inorganic film that is disposed on the surface of the fiber base material and contains an inorganic compound; and functional particles fixed to the surface side of the fiber base material by the inorganic film.

Description

Technical Field

[0001] The present disclosure relates to a substrate with particles and a method for manufacturing a substrate with particles. Background Art

[0002] Conventionally, in order to impart functions such as environmental purification, antibacterial, antiviral, antifungal, and self-cleaning, a technique of fixing functional particles to the surface of a substrate has been known.

[0003] As a technique for fixing functional particles to the surface of a substrate, for example, there is a method using an adhesive. For example, in Patent Document 1 and Patent Document 2, a photocatalytic member having a layer containing photocatalyst particles and an inorganic adhesive is disclosed.

[0004] In addition, as a technique for fixing functional particles to the surface of a substrate, for example, a method of adsorbing functional particles to the surface of a substrate has been proposed. For example, in Patent Document 3, a method of electrostatically adsorbing photocatalyst particles to the surface of polyester fiber is disclosed.

[0005] Prior Art Documents

[0006] Patent Documents

[0007] Patent Document 1: Japanese Unexamined Patent Application Publication No. 2008-272651

[0008] Patent Document 2: Japanese Patent Application Laid-Open No. 2018-528072

[0009] Patent Document 3: Japanese Unexamined Patent Application Publication No. 2007-229667 Summary of the Invention

[0010] Problems to be Solved by the Invention

[0011] In the method using an adhesive as in Patent Document 1 or Patent Document 2, functional particles can be stably fixed to the surface of a substrate. However, at least a part of the functional particles is buried in the adhesive, and there is a problem of reduced function. In particular, when the layer containing functional particles and an adhesive is a dense film and has almost no pores, the functional particles cannot come into contact with substances in the external environment, so the reduction in function is significant.

[0012] In addition, in the method using electrostatic adsorption as in Patent Document 3, since no adhesive is used, the function of the functional particles can be fully exerted. Furthermore, functional particles can be adsorbed at a high density. However, the adhesion of the functional particles to the substrate is insufficient, and there is a problem that the functional particles are likely to fall off.

[0013] The present disclosure has been made in view of the above actual situation, and an object thereof is to provide a particle-bearing substrate and a method for manufacturing the particle-bearing substrate that can stably and densely fix particles to the surface of a substrate while maintaining the functions of the particles.

[0014] Means for Solving the Problem

[0015] One embodiment of the present disclosure provides a particle-bearing substrate having: a fibrous substrate containing inorganic fibers; an inorganic film disposed on the surface of the fibrous substrate and containing an inorganic compound; and functional particles fixed to the surface side of the fibrous substrate through the inorganic film.

[0016] Another embodiment of the present disclosure provides a method for manufacturing a particle-bearing substrate, the method having: a functional group introduction step of introducing a functional group that is positively or negatively charged in water onto the surface of a substrate; a particle electrostatic adsorption step of electrostatically adsorbing functional particles onto the surface of the substrate onto which the functional group has been introduced; and an inorganic film formation step of forming an inorganic film containing an inorganic compound so as to cover the surface of the substrate after the particle electrostatic adsorption step.

[0017] Effect of the Invention

[0018] The present disclosure has the effect of being able to stably and densely fix particles to the surface of a substrate while maintaining the functions of the particles. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Figure 1 is a schematic cross-sectional view illustrating a particle-bearing substrate in the present disclosure.

[0020] Figure 2 is a process chart illustrating a method for manufacturing a particle-bearing substrate in the present disclosure.

[0021] Figure 3 is a schematic cross-sectional view illustrating a particle-bearing substrate in the present disclosure.

[0022] Figure 4 is a schematic cross-sectional view illustrating a particle-bearing substrate in the present disclosure.

[0023] Figure 5 is a schematic cross-sectional view illustrating a particle-bearing substrate in the present disclosure.

[0024] Figure 6 is a process chart illustrating a method for manufacturing a particle-bearing substrate in the present disclosure.

[0025] Figure 7 is an SEM image of polymethylsilsesquioxane (PMSQ) particles in Example 1.

[0026] Figure 8 SEM image of the substrate with particles of Example 1.

[0027] Figure 9 SEM image of the substrate with particles of Example 2. Detailed Description of the Embodiments

[0028] Hereinafter, embodiments of the present disclosure will be described with reference to the drawings and the like. However, the present disclosure can be implemented in a variety of different forms and is not limited to the content described in the following exemplary embodiments. In addition, for the sake of clarity, the width, thickness, shape, etc. of each part may be schematically shown in the drawings as compared with the actual form, but this is only an example and does not limit the interpretation of the present disclosure. In addition, in this specification and each figure, sometimes the same reference numerals are assigned to elements that are the same as those already described in the figures that have appeared, and the detailed description is appropriately omitted.

[0029] Hereinafter, the substrate with particles and the method for manufacturing the substrate with particles in the present disclosure will be described in detail.

[0030] A. Substrate with Particles

[0031] The substrate with particles in the present disclosure has: a fibrous substrate containing inorganic fibers; an inorganic film disposed on the surface of the fibrous substrate and containing an inorganic compound; and particles fixed to the surface side of the fibrous substrate through the inorganic film.

[0032] Figure 1 is a schematic cross-sectional view illustrating the substrate with particles in the present disclosure. As Figure 1 shown, the substrate with particles 10 has: a fibrous substrate 1 containing inorganic fibers, an inorganic film 2 disposed on the surface of the fibrous substrate 1 and containing an inorganic compound, and particles 3 fixed to the surface side of the fibrous substrate 1 through the inorganic film 2.

[0033] In the substrate with particles of the present disclosure, the particles are fixed to the surface side of the fibrous substrate through the inorganic film. The inorganic film is a layer for fixing the particles and contains an inorganic compound but does not contain particles. Therefore, unlike the case of forming a layer using a composition containing particles and a binder as in the past, it is possible to suppress the particles from being buried in the binder. In addition, since the particles are fixed through the inorganic film and are not buried in the binder, they can come into contact with substances in the external environment that gradually diffuse and pass through the inside of the inorganic film. Therefore, the function of the particles can be exerted to a certain extent. At this time, as will be described later, when the inorganic film has a large number of pores having a size that allows substances in the external environment to pass through, the function of the particles can be maximized. Furthermore, since the particles are fixed through the inorganic film, the detachment of the particles can be suppressed. Therefore, the particles can be stably fixed to the surface of the fibrous substrate while maintaining the function of the particles.

[0034] Figure 2 (a) to (d) are process diagrams illustrating a method for manufacturing a substrate with particles in the present disclosure. First, as shown in Figure 2 (a), a positively charged functional group A in water is introduced onto the surface of the fibrous substrate 1. Next, as shown in Figure 2 (b) and Figure 2 (c), particles 3 that are negatively charged in water are electrostatically adsorbed onto the surface of the fibrous substrate 1 onto which the functional group A has been introduced. Next, as shown in Figure 2 (d), an inorganic film 2 containing an inorganic compound is formed so as to cover the surface of the fibrous substrate 1. Thus, a substrate 10 with particles is obtained.

[0035] As described above, the substrate with particles in the present disclosure can be manufactured by forming an inorganic film so as to cover the surface of the fibrous substrate after electrostatically adsorbing the particles onto the surface of the fibrous substrate. By using electrostatic adsorption, the particles can be adsorbed onto the surface of the fibrous substrate at a high density. In addition, as will be described later, the thickness of the inorganic film is preferably thin enough for substances in the external environment to gradually pass through by diffusion. Therefore, the particles can be stably and densely fixed to the surface of the fibrous substrate while maintaining the functions of the particles.

[0036] In addition, in the present disclosure, the fibrous substrate contains inorganic fibers. In addition, the layer for fixing the particles is an inorganic film containing an inorganic compound. Therefore, for example, when the particles are photocatalyst particles, the fibrous substrate and the inorganic film are stable against free radicals generated in the photocatalytic reaction. Therefore, the durability of the substrate with particles can be improved.

[0037] In addition, in the present disclosure, by using a fibrous substrate, the substrate with particles can be manufactured in a roll-to-roll manner. Therefore, the production efficiency can be improved and the manufacturing cost can be reduced.

[0038] Hereinafter, each component of the substrate with particles in the present disclosure will be described.

[0039] 1. Particles

[0040] The particles in the present disclosure are fixed to the surface of the fibrous substrate through an inorganic film.

[0041] The particles are preferably functional particles. Functional particles refer to particles that can affect a substance by contacting the substance. Examples of the functions possessed by the functional particles include photocatalyst function, antibacterial function, antiviral function, antifungal function, ion adsorption function, ion release function, gas adsorption function, gas release function, chemical substance slow release function, humidity control function, catalyst function, adhesion function, water repellent function, rust prevention function, heat transfer function, heat insulation function, electrical conductivity function, insulation function, etc.

[0042] Among them, photocatalyst particles are preferred. Photocatalyst particles can be widely applied in environmental fields such as environmental purification, antibacterial, antiviral, mildew-proof, deodorization, antifouling, antifogging, and self-cleaning.

[0043] As the photocatalyst particles, for example, titanium oxide (TiO 2 ), zinc oxide (ZnO), cadmium sulfide (CdS), niobium oxide (Nb 2 O 5 ), tantalum oxide (Ta 2 O 5 ), tungsten oxide (WO 3 ), molybdenum oxide (MoO 3 ), vanadium oxide (V 2 O 5 ) can be cited.

[0044] In addition, the photocatalyst particles can also carry a substance that improves the activity of the photocatalyst particles. The above-mentioned substance is not particularly limited as long as it can improve the activity of the photocatalyst particles.

[0045] In addition, as the functional particles, metal particles, metal oxide particles, metal carbide particles, metal nitride particles, etc. can be cited. The metal particles can be formed of a metal single substance or an alloy. As the metal particles, for example, silver particles, zinc particles, and copper particles can be cited.

[0046] The average particle size is not particularly limited. For example, it is preferably 0.1 μm or more and 10 μm or less, more preferably 0.2 μm or more and 5 μm or less, and further preferably 0.5 μm or more and 2.5 μm or less. When the average particle size of the particles is relatively large and within the above range, while suppressing the particles from being buried in the inorganic film, the particles can be fixed to the surface of the fiber substrate through the inorganic film. On the other hand, if the average particle size of the particles is too large, the particles may be likely to fall off.

[0047] Here, the particle size of the particles can be measured by observing the cross-section of the substrate with the particles through a scanning electron microscope (SEM). The average particle size of the particles refers to the arithmetic average of the particle sizes of 20 particles measured by SEM observation. It should be noted that when the shape of the particles is not spherical, the particle size is the major axis.

[0048] The shape of the particles is not particularly limited. For example, spherical, cubic, flat plate-shaped, disk-shaped, rod-shaped, needle-shaped, etc. can be cited.

[0049] As a state where the particles are fixed to the surface of the fiber substrate through the inorganic film, for example, it can be cited as: such as Figure 1As shown, a state in which the inorganic film 2 is disposed on the surface of the fibrous substrate 1 in such a manner that all of the particles 3 are covered with the inorganic film 2; and for example Figure 3 As shown, a state in which the inorganic film 2 is disposed on the surface of the fibrous substrate 1 in such a manner that a part of the particles 3 is exposed. In addition, these states may coexist.

[0050] When a part of the particles is exposed, the degree of exposure of the particles, that is, the degree of coverage of the particles by the inorganic film is not particularly limited.

[0051] In addition, for example, as Figure 4 shown, the particles 3 may be fixed to the entire surface of the fibrous substrate 1. For example, as Figure 1 and Figure 3 shown, the particles 3 may also be fixed to a part of the surface of the fibrous substrate 1. For example, the particles may be fixed only to one of the two main surfaces of the fibrous substrate. Among them, the particles are preferably fixed to the entire surface of the fibrous substrate. The functions of the particles can be exerted on the entire surface of the substrate with particles.

[0052] The amount of particles in the substrate with particles is not particularly limited as long as it is an amount capable of exerting the functions of the particles, and can be appropriately set according to the thickness, surface area of the fibrous substrate, type of particles, and use of the substrate with particles. The amount of particles in the substrate with particles is, for example, preferably 0.1 mg / cm 2 or more and 10 mg / cm 2 or less, more preferably 0.5 mg / cm 2 or more and 5 mg / cm 2 or less, and further preferably 1 mg / cm 2 or more and 3 mg / cm 2 or less.

[0053] Here, the amount of particles in the substrate with particles can be measured by recovering the particles from the substrate with particles. For example, when the inorganic film to which the particles are fixed is a silica film, the particles can be recovered by dissolving the silica film with a strong alkali aqueous solution.

[0054] 2. Inorganic film

[0055] The inorganic film in the present disclosure is disposed on the surface of the fibrous substrate and contains an inorganic compound.

[0056] As the inorganic compound, for example, an inorganic compound capable of forming an inorganic film by a sol-gel method or a vapor deposition method can be cited. For example, inorganic oxides, inorganic fluorides, inorganic sulfides, and inorganic nitrides can be cited. As the inorganic oxides, for example, silica, titanium oxide, alumina, zirconia, zinc oxide (ZnO), indium oxide (In 2 O 3), tin oxide (SnO 2 ), indium tin oxide (ITO), tantalum oxide (Ta 2 O 5 ). As the inorganic fluoride, for example, magnesium fluoride (MgF 2 ), aluminum fluoride (AlF 3 ), barium fluoride (BaF 2 ), calcium fluoride (CaF 2 ), cerium fluoride (CeF 3 ), yttrium fluoride (YF 3 ). As the inorganic nitride, for example, aluminum nitride (AlN), silicon nitride (Si 3 N 4 ), titanium nitride (TiN).

[0057] Among them, silica is preferred. The weather resistance and durability of silica are excellent.

[0058] The thickness of the inorganic film is not particularly limited as long as it can fix the particles on the surface of the fibrous substrate through the inorganic film in such a way that the particles can function, and can be appropriately set according to the particle size and shape. For example, when the particles are covered by the inorganic film, the thickness of the inorganic film is preferably a thickness that allows substances to permeate or penetrate, so that the particles can come into contact with the substances. Specifically, the thickness of the inorganic film is preferably 2 nm or more and 100 nm or less, more preferably 5 nm or more and 50 nm or less, and further preferably 10 nm or more and 30 nm or less. When the thickness of the inorganic film is thin and within the above range, even when the particles are covered by the inorganic film, substances can permeate or penetrate the inorganic film, and the particles can come into contact with the substances, so that the particles can function. On the other hand, if the thickness of the inorganic film is too thin, the particles may be likely to fall off.

[0059] Here, the thickness of the inorganic film refers to, for example, Figure 5 the thickness t1 of the inorganic film 2 in the region where there are no particles 3 as shown, and also refers to the thickness t2 of the inorganic film 2 on the surface of the particles 3 when all of the particles 3 are covered by the inorganic film 2. The thickness of the inorganic film can be measured by observing the cross-section of the substrate with particles using a scanning electron microscope (SEM) or a transmission electron microscope (TEM).

[0060] The inorganic film is preferably a porous film. If the inorganic film is a porous film, substances in the external environment can pass through the inorganic film and come into contact with the particles, whereby the particles can function to the maximum extent.

[0061] A porous membrane is a membrane having a large number of fine pores. The inorganic membrane preferably has fine pores sized such that substances in the external environment can pass through. Specifically, the inorganic membrane preferably has fine pores with a pore diameter in the nanometer range. Additionally, the inorganic membrane can have any one of micropores with a pore diameter of 2 nm or less, mesopores with a pore diameter of 2 nm or more and 50 nm or less, and macropores with a pore diameter of 50 nm or more. Among them, from the viewpoint of the fixing force of particles, i.e., the strength of the inorganic membrane, the inorganic membrane preferably has micropores. That is, the inorganic membrane preferably has fine pores with a pore diameter of 0.3 nm or more and 3 nm or less, more preferably with a pore diameter of 0.4 nm or more and 2 nm or less, and still more preferably with a pore diameter of 0.5 nm or more and 1 nm or less.

[0062] "The inorganic membrane has fine pores with a pore diameter in a specified range" means that the inorganic membrane has fine pores, and there are multiple fine pores with a pore diameter in the specified range among the fine pores.

[0063] The pore diameter of the inorganic membrane is a value obtained by observing the surface of the inorganic membrane using a scanning electron microscope (SEM) or a transmission electron microscope (TEM). When the fine pores are mesopores or macropores, SEM is used. On the other hand, when the fine pores are micropores, TEM is used. As described above, it is sufficient that there are multiple fine pores with a pore diameter in the specified range among the fine pores of the inorganic membrane. Among them, it is preferred that there are 100 or more fine pores with a pore diameter in the specified range in a 1 μm square area on the surface of the inorganic membrane, and more preferably 1000 or more.

[0064] In addition, the inorganic membrane can be either an amorphous membrane or a crystalline membrane, and an amorphous membrane is preferred. Amorphous membranes tend to have micropores. Therefore, if the inorganic membrane is an amorphous membrane, substances in the external environment pass through the inorganic membrane and contact the particles, thereby maximizing the function of the particles. Additionally, the fixing force of the particles can also be increased.

[0065] It can be confirmed that the inorganic membrane is an amorphous membrane by X-ray diffraction (XRD). In the X-ray diffraction pattern, if no distinct peaks are observed, it is an amorphous membrane. However, when XRD measurement is difficult, it is confirmed that the inorganic membrane is an amorphous membrane by observing with a transmission electron microscope (TEM). In TEM observation, if an image is observed in which black spots or white spots (i.e., parts where atoms exist) are arranged disorderly, it is an amorphous membrane.

[0066] As a method for forming the inorganic membrane, for example, sol-gel method and evaporation deposition method can be cited. Among them, the sol-gel method is preferred. In the sol-gel method, an amorphous membrane can be formed. That is, the inorganic membrane is preferably an amorphous membrane formed by the sol-gel method. It should be noted that the sol-gel method and the evaporation deposition method are described in the item of "B. Manufacturing method of the substrate with particles" described later.

[0067] Here, it is possible to confirm that the inorganic membrane is an inorganic membrane formed by the sol-gel method through observation with a transmission electron microscope (TEM). In the inorganic membrane formed by the sol-gel method, there is a tendency for an image in which black spots (corresponding to micropores) are arranged disorderly to be observed. For example, in the case of forming an inorganic membrane containing silica by the sol-gel method using tetraethoxysilane (TEOS), an image in which black spots with a diameter of 1 nm or less are arranged disorderly is mostly observed. Generally speaking, the denseness (microstructure) of the inorganic membrane depends greatly on the method of forming the inorganic membrane. For example, it is known that a silica membrane formed by chemical vapor deposition (CVD) is denser than a silica membrane formed by the sol-gel method or physical vapor deposition (PVD). By observing the denseness (microstructure) of the inorganic membrane, it is possible to deduce the method of forming the inorganic membrane.

[0068] 3. Fiber substrate

[0069] The fiber substrate in the present disclosure contains inorganic fibers.

[0070] The inorganic fibers are not particularly limited. For example, glass fibers, ceramic fibers, and carbon fibers can be mentioned. As ceramic fibers, for example, alumina-based fibers, silica fibers, zirconia fibers, silicon carbide fibers, silicon nitride fibers, etc. can be mentioned. As alumina-based fibers, for example, alumina fibers, alumina-silica fibers, and mullite fibers can be mentioned.

[0071] In addition, as inorganic fibers, in addition to the fibers formed of inorganic substances as described above, fibers in which organic fibers formed of organic substances are coated with an inorganic material, an organic-inorganic hybrid material, or a metal material, and fibers in which metal fibers are coated with an inorganic material can also be used.

[0072] The above-mentioned organic fibers are not particularly limited as long as they can be coated with an inorganic material, an organic-inorganic hybrid material, or a metal material. For example, polyester fibers and polyolefin fibers can be mentioned. As the polyolefin constituting the polyolefin fiber, for example, polyethylene, polyethylene copolymers, polypropylene, and polypropylene copolymers can be mentioned.

[0073] The above-mentioned metal fibers are not particularly limited as long as they can be coated with an inorganic material.

[0074] The above-mentioned inorganic materials are not particularly limited as long as they can coat organic fibers or metal fibers. For example, silica can be mentioned. As the above-mentioned organic-inorganic hybrid material, for example, polysiloxane can be mentioned. The above-mentioned metal materials are not particularly limited as long as they can coat organic fibers.

[0075] The method for coating organic fibers with inorganic materials is not particularly limited, and for example, a sol-gel method can be cited. In addition, as a method for coating organic fibers with an organic-inorganic hybrid material, for example, a method of coating an organosilicon compound on organic fibers and heating and curing it can be cited. As the organosilicon compound, for example, alkoxysilane, silicone resin, and polysilazane can be used. As a method for coating organic fibers with a metal material and a method for coating metal fibers with an inorganic material, known methods can be applied.

[0076] Among them, inorganic fibers formed of inorganic substances are preferred. In the case where the particles are photocatalyst particles, by using inorganic fibers formed of inorganic substances, the stability against free radicals generated in the photocatalytic reaction can be improved.

[0077] Among the inorganic fibers formed of inorganic substances, glass fibers and ceramic fibers are preferred. Glass fibers and alumina-based fibers are particularly preferred. Glass fibers and alumina-based fibers have excellent weather resistance, heat resistance, and chemical resistance. Glass fibers are further preferred. Glass fibers are inexpensive, so the manufacturing cost can be reduced.

[0078] The average fiber diameter of the inorganic fibers is not particularly limited. For example, it is 1 μm or more and 50 μm or less, and it can also be 5 μm or more and 20 μm or less. In addition, the average fiber diameter of the inorganic fibers can be, for example, 10 times or more and 20 times or less the average particle diameter of the particles described later. If the average fiber diameter of the inorganic fibers is too large, there is a tendency for the surface area of the inorganic fibers per unit area of the fiber substrate to become small, so the amount of particles fixed to the fiber substrate may become small. In addition, if the average fiber diameter of the inorganic fibers is too small, there is a tendency for the voids between the inorganic fibers in the fiber substrate to become small, so the particles are only fixed flatly on the surface of the fiber substrate, and thus the amount of particles fixed to the fiber substrate may become small. On the other hand, if the average fiber diameter of the inorganic fibers is within the above range, regarding the voids between the inorganic fibers in the fiber substrate, it is possible to ensure a sufficiently large void size for the particles to pass through while moderately increasing the surface area of the inorganic fibers per unit area of the fiber substrate. Therefore, the amount of particles fixed to the fiber substrate can be increased.

[0079] Here, the fiber diameter of the inorganic fibers can be measured by observation with a scanning electron microscope (SEM). The average fiber diameter of the inorganic fibers refers to the arithmetic average of the fiber diameters of 50 inorganic fibers measured by SEM observation.

[0080] As the fiber substrate, for example, non-woven fabric, woven fabric, and knitted fabric can be cited. Among them, non-woven fabric is preferred.

[0081] The inorganic fibers constituting the nonwoven fabric can be short fibers or long fibers. The length of the fibers is, for example, 1 mm or more and 30 mm or less. In addition, in the nonwoven fabric, the method of bonding between the fibers can be any one of entanglement, welding, and adhesion. When the fibers are bonded by an adhesive, the adhesive is not particularly limited, and an adhesive commonly used for nonwoven fabrics can be used. Examples of the adhesive include acrylic resins, epoxy resins, polyvinyl alcohol, melamine resins, polyesters, and polyvinyl chloride.

[0082] The thickness of the fiber substrate is not particularly limited and can be appropriately selected according to the use of the substrate with particles. Specifically, the thickness of the fiber substrate is 0.1 mm or more and 2 mm or less, can be 0.2 mm or more and 1 mm or less, or can be 0.3 mm or more and 0.5 mm or less. Generally, there is a tendency that the thicker the fiber substrate, the more the amount of particles fixed to the fiber substrate. However, in the case of photocatalyst particles, if the fiber substrate is too thick, light is difficult to reach the deep part of the fiber substrate, and there may be an increase in photocatalyst particles that do not contribute to the activity. If the thickness of the fiber substrate is within the above range, the photocatalyst particles can be effectively utilized without waste.

[0083] In addition, the basis weight of the fiber substrate is not particularly limited and can be appropriately selected according to the use of the substrate with particles. Specifically, the basis weight of the fiber substrate is 5 g / m 2 or more and 200 g / m 2 or less, can be 10 g / m 2 or more and 100 g / m 2 or less, or can be 20 g / m 2 or more and 50 g / m 2 or less. Generally, there is a tendency that the larger the basis weight of the fiber substrate, the more the amount of particles fixed to the fiber substrate. However, if the basis weight of the fiber substrate is too large, the fiber substrate becomes thick, and as described above, in the case of photocatalyst particles, there may be an increase in photocatalyst particles that do not contribute to the activity. In addition, if the basis weight of the fiber substrate is too large, the voids in the fiber substrate become smaller, and as described above, the amount of particles fixed to the fiber substrate may become smaller. On the other hand, if the basis weight of the fiber substrate is too small, the fiber substrate becomes thin, and the amount of particles fixed to the fiber substrate may become smaller.

[0084] 4. Manufacturing method of the substrate with particles

[0085] The substrate with particles in the present disclosure can be manufactured by the manufacturing method of the substrate with particles described below.

[0086] B. Manufacturing method of the substrate with particles

[0087] The method for manufacturing a substrate with particles in the present disclosure includes: a functional group introduction step of introducing a functional group that is positively or negatively charged in water onto the surface of the substrate; a particle electrostatic adsorption step of electrostatically adsorbing particles onto the surface of the substrate onto which the above functional group has been introduced; and an inorganic film formation step of forming an inorganic film containing an inorganic compound in a manner covering the surface of the substrate after the above particle electrostatic adsorption step.

[0088] Figure 6 (a) to (d) are process diagrams illustrating the method for manufacturing a substrate with particles in the present disclosure. First, as Figure 6 shown in (a), a functional group A that is positively charged in water is introduced onto the surface of the substrate 11. Next, as Figure 6 shown in (b) and Figure 6 shown in (c), particles 3 that are negatively charged in water are electrostatically adsorbed onto the surface of the substrate 11 onto which the functional group A has been introduced. Next, as Figure 6 shown in (d), an inorganic film 2 containing an inorganic compound is formed in a manner covering the surface of the fibrous substrate 11. Thus, a substrate with particles 20 is obtained.

[0089] In the present disclosure, by utilizing electrostatic adsorption, particles can be adsorbed onto the surface of the substrate at a high density.

[0090] In addition, in the present disclosure, after electrostatically adsorbing particles onto the surface of the substrate, an inorganic film is formed thinly in a manner covering the surface of the substrate, thereby fixing the particles to the surface of the substrate. Therefore, different from the case of forming a layer using a composition containing particles and a binder as in the past, it is possible to suppress the particles from being buried in the binder. In addition, the particles are fixed by the inorganic film and are not buried in the binder, so they can come into contact with substances in the external environment that gradually diffuse and pass through the inside of the inorganic film. Therefore, the function of the particles can be exerted to a certain extent. At this time, as described above, when the inorganic film is a porous film and has a large number of pores of a size that allows substances in the external environment to pass through, the function of the particles can be maximally exerted. Furthermore, since the particles can be fixed to the surface of the substrate through the inorganic film, the shedding of the particles can be suppressed.

[0091] Therefore, it is possible to stably and densely fix the particles to the surface of the fibrous substrate while maintaining the function of the particles.

[0092] In addition, in the present disclosure, as the layer for fixing the particles, an inorganic film containing an inorganic compound is formed. Therefore, for example, when the particles are photocatalyst particles, the inorganic film is stable against free radicals generated in the photocatalytic reaction. Therefore, it is possible to manufacture a substrate with particles having excellent durability.

[0093] Hereinafter, the substrate and particles used in the method for manufacturing a substrate with particles in the present disclosure, and each step of the method for manufacturing a substrate with particles in the present disclosure will be described.

[0094] 1. Substrate

[0095] The form of the substrate used in the present disclosure is not particularly limited, and examples thereof include a film, a sheet, a plate, a fibrous substrate, a filament, a fiber, a bead, a porous body, and a column. As the fibrous substrate, for example, a nonwoven fabric, a woven fabric, and a knitted fabric can be mentioned. The form of the filament is not particularly limited. The filament can be, for example, a hollow filament or a solid filament.

[0096] Among them, the substrate is preferably a fibrous substrate, and more preferably a nonwoven fabric. When the substrate is a fibrous substrate, a substrate with particles can be manufactured by a roll-to-roll method. The fibrous substrate is the same as the fibrous substrate in the above-mentioned substrate with particles.

[0097] The material of the substrate is not particularly limited, and examples thereof include an inorganic substance, an organic polymer, a metal, and a semiconductor. As the inorganic substance, for example, glass, ceramics, and carbon can be mentioned. As the ceramics, for example, alumina-based, silica, zirconia, silicon carbide, and silicon nitride can be mentioned. As the alumina-based, for example, alumina, alumina-silica, and mullite can be mentioned. In addition, as the organic polymer, for example, polyester, nylon, acrylic resin, polyethylene, polypropylene, polyvinyl chloride, phenolic resin, silicone resin, synthetic rubber, cellulose, and triacetate can be mentioned. As the metal, for example, gold, silver, copper, and aluminum can be mentioned. As the semiconductor, for example, silicon, gallium arsenide, and indium phosphide can be mentioned.

[0098] Among them, an inorganic substance is preferred. For example, when the particles are photocatalyst particles, the substrate containing an inorganic substance is stable to the free radicals generated in the photocatalytic reaction.

[0099] In addition, when the substrate is a fibrous substrate, the preferred material of the substrate is the same as that described in the item of "A. Substrate with particles" above.

[0100] As the manufacturing method of the substrate, it can be appropriately selected according to the form and material of the substrate, and a known method can be applied. As the substrate, commercially available products can be used.

[0101] 2. Particles

[0102] The particles used in the present disclosure are the same as the particles in the above-mentioned substrate with particles.

[0103] Here, the particle size of the particles can be measured by observation with a scanning electron microscope (SEM). The average particle size of the particles refers to the arithmetic average of the particle sizes of 20 particles measured by SEM observation. It should be noted that when the shape of the particles is not spherical, the particle size is the major axis.

[0104] In addition, in the inorganic film formation process described later, in order to make the degree of coating of the inorganic film on the particles constant, the classified particles can be used.

[0105] 3. Functional group introduction process

[0106] In the functional group introduction process of the present invention, a functional group that is positively or negatively charged in water is introduced onto the surface of the substrate. By performing the functional group introduction process, in the particle electrostatic adsorption process described later, the particles can be easily electrostatically adsorbed onto the surface of the substrate onto which the functional group has been introduced.

[0107] Among the functional groups that are positively or negatively charged in water, the positive or negative charge can be appropriately selected according to the particles.

[0108] Examples of the functional group that is positively charged in water are not particularly limited, and for example, an amino group, an ammonium group, a pyridinium group, an imidazole group, and a guanidine group can be mentioned.

[0109] In addition, examples of the functional group that is negatively charged in water are not particularly limited, and for example, a carboxyl group, a sulfo group, and a phosphate group can be mentioned.

[0110] In the functional group introduction process, by treating with a compound containing a functional group that is positively or negatively charged in water and a functional group that can bond to the functional group present on the surface of the substrate, a functional group that is positively or negatively charged in water can be introduced onto the surface of the substrate.

[0111] The functional group that can bond to the functional group present on the surface of the substrate is appropriately selected according to the material of the substrate and the surface activation process described later. Examples of the functional group that can bond to the functional group present on the surface of the substrate include an alkoxy group, a hydroxyl group, an acryloyl group, an epoxy group, a urethane group, a vinyl group, and a mercapto group.

[0112] As the compound containing a functional group that is positively or negatively charged in water and a functional group that can bond to the functional group present on the surface of the substrate, it can be appropriately selected according to these functional groups.

[0113] As a compound containing a positively charged functional group in water and a functional group capable of bonding to a functional group present on the surface of a substrate, for example, a compound containing an amino group and an alkoxy group or a hydroxyl group can be cited. As a compound containing an amino group and an alkoxy group or a hydroxyl group, for example, a silane coupling agent containing an amino group or its hydrolyzate can be cited. As a silane coupling agent containing an amino group and its hydrolyzate, for example, 3-aminopropyltrimethoxysilane and its hydrolyzate, 3-aminopropyltriethoxysilane and its hydrolyzate, 3-aminopropylmethyldimethoxysilane and its hydrolyzate, 3-(2-aminoethylamino)propyltrimethoxysilane and its hydrolyzate, 3-(2-aminoethylamino)propyltriethoxysilane and its hydrolyzate, 3-(2-aminoethylamino)propylmethyldimethoxysilane and its hydrolyzate can be cited. The above compounds can be used alone or in combination of two or more.

[0114] As a compound containing a negatively charged functional group in water and a functional group capable of bonding to a functional group present on the surface of a substrate, for example, sodium N-(trimethoxysilyl)ethylenediaminetriacetate, 3-(trihydroxysilyl)-1-propanesulfonic acid, 2-(4-chlorosulfonylphenyl)ethyltrimethoxysilane can be cited. The above compounds can be used alone or in combination of two or more.

[0115] As a method for treating the surface of a substrate with the above compound, there is no particular limitation. For example, a method of coating the above compound on the surface of the substrate, a vapor deposition method can be cited. As a coating method, a known coating method can be applied. For example, spraying, spin coating, dip coating can be cited. In addition, as a vapor deposition method, a physical vapor deposition method (PVD), a chemical vapor deposition method (CVD) can be cited. As a PVD method, for example, a vacuum evaporation method, a sputtering method, an ion plating method can be cited. As a CVD method, for example, a thermal CVD method, a plasma CVD method, a photo CVD method can be cited.

[0116] When coating the above compound on the surface of a substrate, a composition containing the above compound and an organic solvent can be used. When the above compound is a silane coupling agent containing an amino group or its hydrolyzate, as the organic solvent contained in the above composition, an alcohol can be used. As an alcohol, for example, methanol, ethanol, n-propanol, isopropanol, n-butanol can be cited.

[0117] In addition, when using a silane coupling agent, the above composition can further contain water. When the above composition contains water, a hydrolysis reaction of the silane coupling agent occurs in the above composition. Thereby, a composition containing a hydrolyzate of the silane coupling agent as the above compound is obtained.

[0118] In addition, when the above compound is a silane coupling agent containing an amino group or a hydrolyzate thereof, the above composition may further contain a water-soluble polymer. By including a water-soluble polymer in the above composition, the dispersibility of the silane coupling agent containing an amino group or a hydrolyzate thereof becomes good. Therefore, it is possible to uniformly introduce functional groups that are positively or negatively charged in water onto the surface of the substrate. In addition, as described later, when the above composition is dried after coating, it is possible to suppress the removal of the silane coupling agent containing an amino group or a hydrolyzate thereof during drying. Examples of the water-soluble polymer include polyvinyl alcohol, ethylene-vinyl alcohol copolymer, polyacrylic acid, and polyethylene glycol. Among them, polyvinyl alcohol is preferred.

[0119] On the other hand, when the above compound is a silane coupling agent containing an amino group or a hydrolyzate thereof, the above composition may not contain a water-soluble polymer. In this case, it is possible to suppress the hindrance of the introduction of functional groups that are positively or negatively charged in water onto the surface of the substrate due to the water-soluble polymer.

[0120] The content of the water-soluble polymer in the above composition is, for example, 100 parts by mass or less, 10 parts by mass or less, or 1 part by mass or less relative to 100 parts by mass of the above compound.

[0121] When the above compound is a silane coupling agent containing an amino group or a hydrolyzate thereof, the above composition can be dried after coating. The drying method is not particularly limited as long as it can be dried at room temperature. For example, air knife drying, rotary drying, vacuum drying, and extrusion drying can be cited. The drying method can be used alone or in combination of two or more.

[0122] In addition, when the above compound is a silane coupling agent containing an amino group or a hydrolyzate thereof, after coating the above composition and drying as needed, a heat treatment is performed. Thereby, a condensation reaction is carried out to fix the above compound on the surface of the substrate. The temperature and time in the heat treatment can be appropriately selected according to the type of the silane coupling agent. When using a silane coupling agent containing an amino group or a hydrolyzate thereof, the heating temperature is, for example, 40 °C or higher and 250 °C or lower, 70 °C or higher and 200 °C or lower, or 100 °C or higher and 150 °C or lower. In addition, when using a silane coupling agent containing an amino group or a hydrolyzate thereof, the heating time is, for example, 10 seconds or longer and 30 minutes or shorter, 30 seconds or longer and 10 minutes or shorter, or 60 seconds or longer and 5 minutes or shorter.

[0123] The thickness of the film containing the above compound is usually thin, and it is sufficient as long as it is at least the thickness of a monolayer film. The thickness of the film containing the above compound is, for example, 2 nm or more and 20 nm or less.

[0124] 4. Particle electrostatic adsorption process

[0125] In the particle electrostatic adsorption step in the present disclosure, particles are electrostatically adsorbed onto functional groups that are positively or negatively charged in water and introduced onto the surface of the above-mentioned substrate. In the particle electrostatic adsorption step, the particles are electrostatically adsorbed onto the surface of the substrate by utilizing the electrostatic interaction that occurs between the functional groups that are positively or negatively charged in water and introduced onto the surface of the substrate in the above-mentioned functional group introduction step and the particle surface.

[0126] It should be noted that when the surface of the particles is completely or almost uncharged, it is preferable to perform the organic polymer adsorption step as described later.

[0127] In the particle electrostatic adsorption step, by coating a composition containing particles, water, and an organic solvent onto the surface of the substrate, the particles can be electrostatically adsorbed onto the surface of the substrate onto which functional groups that are positively or negatively charged in water have been introduced. As the coating method, known coating methods can be applied, for example, spraying, spin coating, and dip coating can be cited.

[0128] As the organic solvent contained in the above-mentioned composition, an alcohol can be used. As the alcohol, for example, methanol, ethanol, n-propanol, isopropanol, and n-butanol can be cited.

[0129] In addition, the above-mentioned composition may further contain a water-soluble polymer. As the water-soluble polymer, for example, polyvinyl alcohol, ethylene-vinyl alcohol copolymer, polyacrylic acid, and polyethylene glycol can be cited.

[0130] After coating the above-mentioned composition, drying is optionally performed. The drying method is not particularly limited, for example, air knife drying, heat drying, vacuum drying, rotary drying, and extrusion drying can be cited. The drying method can be used alone or in combination of two or more.

[0131] Among them, when the substrate is a fibrous substrate and the method for forming the inorganic film in the inorganic film forming step described later is the sol-gel method, heat drying is preferably performed. By heat drying, the fibrous substrate is sufficiently dried, so that in the inorganic film forming step, it is easy for the composition containing metal alkoxide, water, and solvent to penetrate into the fibrous substrate as the substrate. Thereby, an inorganic film can be uniformly formed on the entire surface of the fibrous substrate as the substrate.

[0132] In the case of heat drying, the drying temperature and drying time are appropriately selected according to, for example, the type of particles and the type and amount of the solvent. The drying temperature is, for example, 40°C or higher and 250°C or lower, can be 70°C or higher and 200°C or lower, or can be 100°C or higher and 150°C or lower. In addition, the drying time is, for example, 10 seconds or longer and 30 minutes or shorter, can be 30 seconds or longer and 10 minutes or shorter, or can be 60 seconds or longer and 5 minutes or shorter.

[0133] 5. Inorganic film forming step

[0134] In the inorganic film forming process in the present disclosure, after the above-described particle electrostatic adsorption process, an inorganic film containing an inorganic compound is formed so as to cover the surface of the substrate. By performing the inorganic film forming process, the particles electrostatically adsorbed on the surface of the substrate can be firmly fixed, and the detachment of the particles can be suppressed.

[0135] The inorganic compound is the same as the inorganic compound used in the inorganic film in the above-described substrate with particles.

[0136] As a method for forming the inorganic film, there is no particular limitation as long as it is a method capable of forming an inorganic film so as to cover the surface of the substrate. For example, a sol-gel method and a vapor deposition method can be cited.

[0137] In addition, when the inorganic compound is silica, the method for forming the inorganic film is preferably a method of treating the surface of the substrate with an organosilicon compound. As a method of treating the surface of the substrate with an organosilicon compound, as described above, for example, a sol-gel method and a vapor deposition method can be cited.

[0138] As the vapor deposition method, a physical vapor deposition method (PVD) and a chemical vapor deposition method (CVD) can be cited. As the PVD method, for example, a vacuum evaporation method, a sputtering method, and an ion plating method can be cited. As the CVD method, for example, a thermal CVD method, a plasma CVD method, and a photo CVD method can be cited.

[0139] Among them, the sol-gel method is preferred.

[0140] In the sol-gel method, a composition containing a metal alkoxide, water, and an organic solvent is prepared, the composition is coated on the surface of the substrate, and heat treatment is performed. In the above composition, the hydrolysis reaction and polycondensation reaction of the metal alkoxide proceed. Further, by heat treatment, it becomes an inorganic oxide.

[0141] As the metal alkoxide used in the above composition, a metal alkoxide represented by the following general formula (1) can be cited.

[0142] R 1 n M(OR 2 ) m (1)

[0143] (In the above formula (1), R 1 and R 2 each independently represent an organic group having 1 or more and 8 or less carbon atoms, M represents a metal atom, n represents an integer of 0 or more, m represents an integer of 1 or more, and n + m represents the valence of M.)

[0144] As the metal atom M, for example, silicon, zirconium, titanium, and aluminum can be cited. Among them, silicon is preferred.

[0145] As the organic group represented by R 1 and R 2 Examples of the organic group include an alkyl group. Examples of the alkyl group include a methyl group, an ethyl group, a n-propyl group, an isopropyl group, a n-butyl group, and an isobutyl group. In the same molecule, these alkyl groups may be the same or different.

[0146] n is preferably 0.

[0147] The metal alkoxide is not particularly limited. For example, a metal alkoxide in which the metal atom M is silicon and n is 0 is a tetraalkoxysilane. Examples of the tetraalkoxysilane include tetramethoxysilane, tetraethoxysilane, tetrapropoxysilane, and tetrabutoxysilane. The metal alkoxide may be used alone or in combination of two or more.

[0148] In the above composition, the metal alkoxide may be partially hydrolyzed or partially condensed to form an oligomer. That is, the above composition may contain a hydrolyzate or a hydrolysis condensate of the metal alkoxide.

[0149] As the organic solvent contained in the above composition, an alcohol can be used. Examples of the alcohol include methanol, ethanol, n-propanol, isopropanol, and n-butanol.

[0150] In addition, the above composition may further contain a water-soluble polymer. By making the above composition contain a water-soluble polymer, the dispersibility of the metal alkoxide or its hydrolyzate or hydrolysis condensate becomes good. Therefore, an inorganic film can be uniformly formed on the surface of the substrate. In addition, as described later, when the above composition is dried after coating, the metal alkoxide or its hydrolyzate or hydrolysis condensate can be inhibited from being removed during drying. Examples of the water-soluble polymer include polyvinyl alcohol, ethylene-vinyl alcohol copolymer, polyacrylic acid, and polyethylene glycol. Among them, polyvinyl alcohol is preferred. Polyvinyl alcohol is usually obtained by saponifying polyvinyl acetate. The polyvinyl alcohol may be a partially saponified polyvinyl alcohol in which several tens of percentages of acetyl groups remain, or a completely saponified polyvinyl alcohol in which no acetyl group remains, and a completely saponified polyvinyl alcohol is preferred. In addition, the degree of polymerization of polyvinyl alcohol is, for example, 1500 or more and 2000 or less.

[0151] Regarding the content of the water-soluble polymer in the above composition, for example, it is 1 part by mass or more and 100 parts by mass or less, 5 parts by mass or more and 50 parts by mass or less, or 10 parts by mass or more and 25 parts by mass or less with respect to 100 parts by mass of the above compound.

[0152] The above composition optionally contains, as needed, a catalyst that promotes the hydrolysis reaction of metal alkoxides, and a stabilizer that controls the polycondensation reaction of metal alkoxides. Examples of the catalyst include hydrochloric acid, sulfuric acid, nitric acid, and carboxylic acids. Examples of the stabilizer include acetylacetone, amino alcohols, alkylamines, and N,N-dimethylformamide. It should be noted that when tetraethoxysilane (TEOS) is used, the stabilizer may not be added.

[0153] As a method for coating the above composition, known coating methods can be applied, and examples thereof include spraying, spin coating, and dip coating.

[0154] When coating the above composition, the coating degree of the inorganic film on the particles can be controlled by adjusting the coating conditions.

[0155] Drying may also be performed after coating the above composition. The drying method is not particularly limited as long as it can be dried at room temperature. Examples thereof include air knife drying, rotary drying, vacuum drying, and extrusion drying. The drying method can be used alone or in combination of two or more.

[0156] After coating the above composition and drying as needed, a heat treatment is performed. Regarding the temperature and time in the heat treatment, there is no particular limitation as long as an inorganic oxide can be obtained, and it can be appropriately selected according to the type of metal alkoxide, for example. The heating temperature is, for example, 40°C or higher and 250°C or lower, can be 70°C or higher and 200°C or lower, or can be 100°C or higher and 150°C or lower. In addition, the heating time is, for example, 10 seconds or longer and 30 minutes or shorter, can be 30 seconds or longer and 10 minutes or shorter, or can be 60 seconds or longer and 5 minutes or shorter.

[0157] In addition, in the case of the method of treating the surface of the substrate with an organosilicon compound, the organosilicon compound is preferably a tetraalkoxysilane or its hydrolyzate or hydrolysis polycondensate as described above.

[0158] The thickness of the inorganic film is the same as that of the inorganic film in the above substrate with particles.

[0159] 6. Surface activation step

[0160] The method for manufacturing the substrate with particles in the present disclosure may have a surface activation step of performing a surface activation treatment on the surface of the substrate before the above functional group introduction step. By performing the surface activation step, it is easy to introduce a specified functional group to the surface of the substrate in the above functional group introduction step.

[0161] Examples of the surface activation treatment include physical treatment, chemical treatment, and thin film formation.

[0162] As physical treatment, for example, corona treatment, plasma treatment, ultraviolet treatment, electron beam treatment, and flame treatment can be cited.

[0163] As chemical treatment, for example, solvent treatment and chemical agent treatment can be cited.

[0164] In the case of film formation, as the film, an inorganic film containing an inorganic compound can be cited. The inorganic film is the same as the inorganic film in the above-mentioned inorganic film formation process. In addition, regarding the film formation method, it is the same as the film formation method of the inorganic film in the above-mentioned inorganic film formation process.

[0165] 7. Organic polymer adsorption process

[0166] The manufacturing method of the substrate with particles in the present disclosure can have an organic polymer adsorption process in which an organic polymer having at least one of positive charge or negative charge in water is adsorbed on the surface of the particles before the above-mentioned particle electrostatic adsorption process. In this case, the functional group having positive charge or negative charge in water introduced onto the surface of the substrate and the organic polymer have opposite charges to each other in water. It should be noted that in the case where the organic polymer has both positive and negative charges in the molecule, the net charge in water should be considered.

[0167] When the surface of the particles is completely or almost uncharged, the organic polymer adsorption process is preferably carried out.

[0168] The organic polymer only needs to be an organic polymer containing a functional group having positive charge or negative charge in water. The functional group having positive charge or negative charge in water contained in the organic polymer is the same as the functional group having positive charge or negative charge in water used in the above-mentioned functional group introduction process.

[0169] As the organic polymer having positive charge in water, there is no particular limitation, and for example, polyethyleneimine can be cited.

[0170] As the organic polymer having negative charge in water, there is no particular limitation, and for example, polycarboxylic acid can be cited. As the polycarboxylic acid, for example, polyacrylic acid and polymethacrylic acid can be cited.

[0171] In addition, the organic polymer can also contain both a functional group having positive charge in water and a functional group having negative charge in water. As such an organic polymer, for example, gelatin and collagen can be cited.

[0172] The weight-average molecular weight of the organic polymer is, for example, 10,000 or more and 1,000,000 or less, and can also be 50,000 or more and 250,000 or less. It should be noted that the weight-average molecular weight is a value measured by gel permeation chromatography (GPC) method using polystyrene as a standard substance.

[0173] In the organic polymer adsorption step, by dispersing particles in a composition containing an organic polymer, the organic polymer can be adsorbed onto the surface of the particles.

[0174] The above composition may contain an organic polymer and a solvent. As the solvent, it can be appropriately selected according to the type of the organic polymer, and water can be cited as an example. That is, as the above composition, an aqueous solution obtained by dissolving an organic polymer can be used.

[0175] After dispersing the particles in the above composition, the particles are optionally washed. Thereby, the unadsorbed organic polymer can be removed.

[0176] 8. Others

[0177] The method for manufacturing the substrate with particles in the present disclosure can be carried out in a single-piece manner or in a roll-to-roll manner. In the case of the roll-to-roll manner, the roll-to-roll manner can be applied to each step, or each step can be continuously carried out by the roll-to-roll manner.

[0178] In the substrate with particles manufactured by the method for manufacturing the substrate with particles in the present disclosure, the amount of the particles is not particularly limited as long as it is an amount that can exert the functions of the particles, and can be appropriately set according to the type of the particles and the use of the substrate with particles. The amount of the particles in the substrate with particles corresponds to the mass increase before and after the particle electrostatic adsorption step. Therefore, the particle fixation rate is defined as follows in formula (1).

[0179] Particle fixation rate [%]

[0180] =(Mass of the particles fixed to the substrate) / (Mass of the substrate with particles)

[0181] =(Mass after the particle electrostatic adsorption step - Mass before the particle electrostatic adsorption step) / (Mass of the substrate with particles) (1)

[0183] The above particle fixation rate is preferably 1% or more and 50% or less, more preferably 5% or more and 25% or less, for example.

[0184] In addition, the present disclosure is not limited to the above embodiments. The above embodiments are illustrative, and technical solutions having substantially the same constitution as the technical concept described in the scope of protection claimed in the present disclosure and exhibiting the same effects are all included in the technical scope of the present disclosure.

[0185] Examples

[0186] Hereinafter, examples and comparative examples are shown to further illustrate the present disclosure.

[0187] [Example 1]

[0188] (1) Surface activation process

[0189] Prepare liquid medicine 1 with the following composition. After stirring liquid medicine 1 at room temperature for 30 minutes, it becomes a uniform colorless and transparent solution. It should be noted that tetraethoxysilane is directly used as a commercially available product.

[0190] <Liquid medicine 1>

[0191] Tetraethoxysilane (manufactured by Tokyo Chemical Industry Co., Ltd.) 5.5 g

[0192] IPA 1.5 g

[0193] Pure water 7.5 g

[0194] Hydrochloric acid (0.5 M) 180 μL

[0195] Prepare liquid medicine 2 with the following composition. After stirring liquid medicine 2 at a liquid temperature of 80°C to 90°C for 20 minutes, it becomes a uniform colorless and transparent solution. It should be noted that polyvinyl alcohol (degree of polymerization 1500, fully saponified type) is directly used as the polyvinyl alcohol manufactured by Fujifilm Wako Pure Chemical Corporation.

[0196] <Liquid medicine 2>

[0197] Polyvinyl alcohol (degree of polymerization 1500, fully saponified type) (manufactured by Fujifilm Wako Pure Chemical Corporation) 2.5 g

[0198] Pure water 47.5 g

[0199] Prepare coating A with the following composition. After stirring coating A at room temperature for 1 minute, it becomes a uniform colorless and transparent solution.

[0200] <Coating A>

[0201] Liquid medicine 1 12.5 g

[0202] Liquid medicine 2 17.5 g

[0203] Immerse a glass fiber non-woven fabric cut into a size of 5 cm square (mass 65.9 mg, thickness 0.20 mm, unit area weight 25 g / m 2 , fiber diameter 10 μm) in coating A and immediately lift it. After removing the excess coating A by centrifugal operation (centrifugal force 500×g, 1 minute), heat it at 180°C for 2 minutes. As a result, the mass increased by 1.6 mg. It should be noted that the mass is measured using an electronic balance (manufactured by Mettler Toledo, model: AB104-S, minimum display: 0.1 mg).

[0204] (2) Functional group introduction process

[0205] Prepare Coating B with the following composition. Coating B becomes a uniform colorless transparent solution after stirring at room temperature for 10 minutes. It should be noted that 3-aminopropyltrimethoxysilane is directly used as a commercially available product.

[0206] <Coating B>

[0207] 3-aminopropyltrimethoxysilane (manufactured by Tokyo Chemical Industry Co., Ltd.) 1.0 g

[0208] IPA 5.0 g

[0209] Pure water 45.0 g

[0210] Immerse the glass fiber non-woven fabric after the surface activation process in Coating B. After confirming that Coating B has fully penetrated into the glass fiber non-woven fabric, immediately lift the glass fiber non-woven fabric. After removing the excess Coating B by centrifugation (centrifugal force 500×g, 1 minute), heat it at 180°C for 2 minutes. No increase in mass was confirmed.

[0211] (3)Synthesis of polymethylsilsesquioxane particles

[0212] Synthesize polymethylsilsesquioxane (PMSQ) particles according to the following steps. First, stir 10 g of methyltriethoxysilane (manufactured by Tokyo Chemical Industry Co., Ltd.), 8 g of ethanol, and 1 g of hydrochloric acid (0.1 M) at room temperature for 30 minutes. Add 70 mL of sodium dodecyl sulfate aqueous solution (0.01 mass%) and 10 mL of ammonia water (29 mass%) thereto, and stir for 30 minutes. Sediment the formed particles by centrifugation and remove the supernatant.

[0213] Next, disperse the sedimented particles in 15 mL of IPA, and add 15 g of sodium hydroxide aqueous solution (50 mM). After 15 minutes, sediment the particles by centrifugation and remove the supernatant.

[0214] (4)Organic polymer adsorption process

[0215] Disperse the above PMSQ particles in 20 g of gelatin aqueous solution (0.05%), and stir for 60 minutes. Then, sediment the particles by centrifugation and remove the supernatant. Disperse the sedimented particles in 40 mL of pure water, and sediment them again by centrifugation to remove the supernatant. Finally, disperse the sedimented particles in methanol aqueous solution (10 wt%) (solid component concentration 2.4 mass%). According to SEM observation, the average particle size of PMSQ particles is about 1 μm. Figure 7 The SEM photograph is shown.

[0216] (5)Particle electrostatic adsorption process

[0217] The glass fiber nonwoven fabric after the functional group introduction step was immersed in a dispersion of PMSQ particles adsorbed with gelatin on the surface. After confirming that the dispersion had sufficiently penetrated into the glass fiber nonwoven fabric, the glass fiber nonwoven fabric was immediately lifted. After removing the excess dispersion by centrifugation (centrifugal force: 500×g, 1 minute), it was heated at 180 °C for 2 minutes. As a result, the mass increased by 4.4 mg.

[0218] (6) Inorganic membrane formation step

[0219] The glass fiber nonwoven fabric after the particle electrostatic adsorption step was immersed in Coating A. After confirming that Coating A had sufficiently penetrated into the glass fiber nonwoven fabric, the glass fiber nonwoven fabric was immediately lifted. After removing the excess Coating A by centrifugation (centrifugal force: 500×g, 1 minute), it was heated at 180 °C for 2 minutes. As a result, the mass increased by 2.2 mg. The mass of the final substrate with particles was 74.7 mg, and the particle fixation rate was 5.9%.

[0220] (7) Evaluation

[0221] The obtained substrate with particles was observed by SEM, and as a result, it was found that the PMSQ particles were densely fixed in a state covered with a silica film. Figure 8 The SEM photograph of the glass fiber nonwoven fabric before fixing the particles is shown in (b), Figure 8 The SEM photograph of the substrate with particles is shown in (a). Even when the substrate with particles was ultrasonically treated in water, the PMSQ particles did not fall off. In addition, even when the substrate with particles was gently rubbed with a finger, the PMSQ particles did not adhere to the finger.

[0222] [Example 2]

[0223] (1) Surface activation step and functional group introduction step

[0224] Except for using a glass fiber nonwoven fabric cut into a 5 cm square size (mass: 66.3 mg, thickness: 0.20 mm, basis weight: 25 g / m 2 , fiber diameter: 10 μm), the surface activation step and the functional group introduction step were carried out in the same manner as in Example 1.

[0225] (2) Particle electrostatic adsorption step

[0226] Using titanium oxide particles (manufactured by Kanto Chemical Co., Inc., particle size: 0.1 μm to 0.3 μm), a titanium oxide aqueous dispersion (2 mass%) was prepared. It should be noted that since the titanium oxide particles are originally negatively charged in water, the organic polymer adsorption step is not required.

[0227] The glass fiber nonwoven fabric after the functional group introduction step is immersed in a titanium oxide aqueous dispersion. After confirming that the titanium oxide aqueous dispersion has sufficiently penetrated into the glass fiber nonwoven fabric, the glass fiber nonwoven fabric is immediately lifted. After removing the excess titanium oxide aqueous dispersion by centrifugation (centrifugal force: 500×g, 1 minute), it is heated at 180°C for 2 minutes. As a result, the mass increased by 3.7 mg.

[0228] (3) Inorganic membrane formation step

[0229] The glass fiber nonwoven fabric after the particle electrostatic adsorption step is immersed in Coating A. After confirming that the coating has sufficiently penetrated into the glass fiber nonwoven fabric, the glass fiber nonwoven fabric is immediately lifted. After removing the excess coating by centrifugation (centrifugal force: 500×g, 1 minute), it is heated at 180°C for 2 minutes. As a result, the mass increased by 1.7 mg. The mass of the final particle-bearing substrate is 72.4 mg, and the particle fixation rate is 5.1%.

[0230] (4) Evaluation

[0231] The obtained particle-bearing substrate was observed by SEM, and as a result, it was found that the titanium oxide particles were densely fixed in a state covered with a silica film. Figure 9 The SEM photograph is shown. Even when the particle-bearing substrate was ultrasonically treated in water, the titanium oxide particles did not fall off. In addition, even when the particle-bearing substrate was gently rubbed with a finger, the titanium oxide particles did not adhere to the finger.

[0232] In addition, a part of the silica film of the particle-bearing substrate was intentionally damaged and the cross-section of the silica film was observed by SEM. As a result, it was found that the thickness of the silica film was about 50 nm. Furthermore, TEM observation of the silica film fragment after damage was performed, and an image in which black spots were arranged disorderly was observed. This is a characteristic observation image of an amorphous film, and based on the size of these spots, the pore size was estimated to be 1 nm or less.

[0233] [Example 3]

[0234] In the inorganic membrane formation step, Coating A was diluted 2-fold with pure water, and otherwise, a particle-bearing substrate was produced in the same manner as in Example 2. At this time, since the mass increased by 0.3 mg in the inorganic membrane formation step, the thickness of the silica film was estimated to be 10 nm. Even when the particle-bearing substrate was ultrasonically treated in water, the titanium oxide particles did not fall off. In addition, even when the particle-bearing substrate was gently rubbed with a finger, the titanium oxide particles did not adhere to the finger.

[0235] [Example 4]

[0236] In the inorganic film forming step, Coating A was diluted 4 times with pure water. Otherwise, a substrate with particles was produced in the same manner as in Example 2. At this time, since the mass increased by 0.1 mg in the inorganic film forming step, the thickness of the silica film was presumed to be 3 nm. Even when the substrate with particles was ultrasonically treated in water, the titanium oxide particles did not fall off. In addition, even when the substrate with particles was gently rubbed with a finger, the titanium oxide particles did not adhere to the finger.

[0237] [Example 5]

[0238] In the particle electrostatic adsorption step, polystyrene (PS) particles (manufactured by Merck, particle size 5 μm) were used. Otherwise, a substrate with particles was produced in the same manner as in Example 2. At this time, since the mass increased by 2.7 mg in the inorganic film forming step, the thickness of the silica film was presumed to be 79 nm. Even when the substrate with particles was ultrasonically treated in water, the polystyrene particles did not fall off. In addition, even when the substrate with particles was gently rubbed with a finger, the polystyrene particles did not adhere to the finger.

[0239] [Comparative Example 1]

[0240] A substrate with particles was produced in the same manner as in Example 1 except that the inorganic film forming step was omitted. When the obtained substrate with particles was ultrasonically treated in water, it was found that most of the PMSQ particles fell off. In addition, when the substrate with particles was gently rubbed with a finger, PMSQ particles adhered to the finger. From this, it can be seen that the inorganic film forming step is necessary to prevent the particles from falling off.

[0241] The data of the above examples and comparative examples are summarized in Table 1.

[0242] [Table 1]

[0243]

[0244] The present disclosure provides the following [1] to

[18] .

[0245] [1] Provided is a substrate with particles, which has:

[0246] A fibrous substrate containing inorganic fibers;

[0247] An inorganic film disposed on the surface of the fibrous substrate and containing an inorganic compound; and

[0248] Functional particles fixed to the surface side of the fibrous substrate through the inorganic film.

[0249] [2] The substrate with particles according to [1], wherein the thickness of the inorganic film is 2 nm or more and 100 nm or less.

[0250] [3] The base material with particles according to [1] or [2], wherein the inorganic film is a porous film.

[0251] [4] The base material with particles according to any one of [1] to [3], wherein the average particle diameter of the functional particles is 0.1 μm or more and 10 μm or less.

[0252] [5] The base material with particles according to any one of [1] to [4], wherein the functional particles are photocatalyst particles.

[0253] [6] The base material with particles according to any one of [1] to [5], wherein the inorganic compound is silica.

[0254] [7] The base material with particles according to any one of [1] to [6], wherein the inorganic fiber is glass fiber or alumina-based fiber.

[0255] [8] A method for manufacturing a base material with particles, comprising:

[0256] A functional group introduction step of introducing a functional group that is positively or negatively charged in water onto the surface of the base material;

[0257] A particle electrostatic adsorption step of electrostatically adsorbing functional particles onto the surface of the base material onto which the functional group has been introduced; and

[0258] An inorganic film formation step of forming an inorganic film containing an inorganic compound on the surface of the base material so as to cover the surface of the base material after the particle electrostatic adsorption step.

[0259] [9] The method for manufacturing a base material with particles according to [8], wherein the average particle diameter of the functional particles is 0.1 μm or more and 10 μm or less.

[0260]

[10] The method for manufacturing a base material with particles according to [8] or [9], wherein the functional particles are photocatalyst particles.

[0261]

[11] The method for manufacturing a base material with particles according to any one of [8] to

[10] , wherein the inorganic compound is silica, and in the inorganic film formation step, the surface of the base material is treated with an organosilicon compound.

[0262]

[12] The method for manufacturing a base material with particles according to

[11] , wherein the organosilicon compound is tetraalkoxysilane or its hydrolyzate or hydrolysis condensate.

[0263]

[13] The manufacturing method of the substrate with particles according to any one of [8] to

[12] , wherein, in the above functional group introduction step, the surface of the above substrate is treated with a silane coupling agent containing an amino group or its hydrolyzate.

[0264]

[14] The manufacturing method of the substrate with particles according to any one of [8] to

[13] , wherein, before the above functional group introduction step, there is a surface activation step of performing surface activation treatment on the surface of the above substrate.

[0265]

[15] The manufacturing method of the substrate with particles according to any one of [7] to

[13] , wherein, before the above particle electrostatic adsorption step, there is an organic polymer adsorption step of adsorbing an organic polymer that is positively or negatively charged in water on the surface of the above functional particles, and the above functional group and the above organic polymer have opposite charges in water.

[0266]

[16] The manufacturing method of the substrate with particles according to any one of [8] to

[15] , wherein the above substrate is a fiber substrate.

[0267]

[17] The manufacturing method of the substrate with particles according to

[16] , wherein the above fiber substrate contains inorganic fibers.

[0268]

[18] The manufacturing method of the substrate with particles according to

[17] , wherein the above inorganic fibers are glass fibers or alumina-based fibers.

[0269] Description of reference numerals

[0270] 1…Fiber substrate

[0271] 2…Inorganic film

[0272] 3…Particles

[0273] 10…Substrate with particles

[0274] 11…Substrate

[0275] 20…Substrate with particles

Claims

1. A substrate with particles, which has: A fibrous substrate, which contains inorganic fibers; An inorganic film, which is disposed on the surface of the fibrous substrate and contains an inorganic compound; and Functional particles, which are fixed to the surface side of the fibrous substrate through the inorganic film.

2. The substrate with particles according to claim 1, wherein, The thickness of the inorganic film is 2 nm or more and 100 nm or less.

3. The substrate with particles according to claim 1 or 2, wherein, The inorganic film is a porous film.

4. The substrate with particles according to claim 1 or 2, wherein, The average particle size of the functional particles is 0.1 μm or more and 10 μm or less.

5. The substrate with particles according to claim 1 or 2, wherein, The functional particles are photocatalyst particles.

6. The substrate with particles according to claim 1 or 2, wherein, The inorganic compound is silica.

7. The substrate with particles according to claim 1 or 2, wherein, The inorganic fibers are glass fibers or alumina-based fibers.

8. A method for manufacturing a substrate with particles, which has: A functional group introduction step, which introduces a functional group that is positively or negatively charged in water onto the surface of the substrate; A particle electrostatic adsorption step, which causes functional particles to electrostatically adsorb onto the surface of the substrate onto which the functional group has been introduced; and An inorganic film formation step, which, after the particle electrostatic adsorption step, forms an inorganic film containing an inorganic compound so as to cover the surface of the substrate.

9. The method for manufacturing a substrate with particles according to claim 8, wherein, The average particle size of the functional particles is 0.1 μm or more and 10 μm or less.

10. The method for manufacturing a substrate with particles according to claim 8 or 9, wherein, The functional particles are photocatalyst particles.

11. The method for manufacturing a substrate with particles according to claim 8 or 9, wherein, The inorganic compound is silica, In the inorganic film formation step, the surface of the substrate is treated with an organosilicon compound.

12. The method for manufacturing a substrate with particles according to claim 11, wherein, The organosilicon compound is tetraalkoxysilane or its hydrolyzate or hydrolysis condensate.

13. The method for manufacturing a substrate with particles according to claim 8 or 9, wherein, In the functional group introduction step, the surface of the substrate is treated with a silane coupling agent containing an amino group or its hydrolyzate.

14. The method for manufacturing a substrate with particles according to claim 8 or 9, wherein, Before the functional group introduction step, there is a surface activation step of performing surface activation treatment on the surface of the substrate.

15. The method for manufacturing a substrate with particles according to claim 8 or 9, wherein, Before the particle electrostatic adsorption step, there is an organic polymer adsorption step of causing an organic polymer that is at least one of positively or negatively charged in water to adsorb onto the surface of the functional particles, and the functional group and the organic polymer have opposite charges in water.

16. The manufacturing method of a substrate with particles according to claim 8 or 9, wherein, the substrate is a fibrous substrate.

17. The manufacturing method of a substrate with particles according to claim 16, wherein, the fibrous substrate contains inorganic fibers.

18. The manufacturing method of a substrate with particles according to claim 17, wherein, the inorganic fibers are glass fibers or alumina-based fibers.

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