Composite material

Abstract

A composite material comprising: a material comprising nanofibers and / or a two-dimensional substance, the nanofibers and the two-dimensional substance being represented by the formula MQaOb (wherein M is at least one element selected from the group consisting of elements belonging to Groups 3, 4, 5, 6, and 7, Q is at least one element (excluding O) selected from the group consisting of elements belonging to Groups 12, 13, 14, 15, and 16, a is 0-2, and b is larger than 0 but not larger than 2); and a resin having a negative zeta potential.

Description

composite material

[0001] The present disclosure relates to composite materials.

[0002] Conventionally, as an oxide containing a metal, for example, TiO ２ For example, AEROXIDE (registered trademark) TiO ２ P-25 is a hydrophilic titanium dioxide with a particle size of 20 to 30 nm and a very high specific surface area. As shown in Non-Patent Document 1, titanium dioxide is suitable for many catalytic applications, particularly photocatalytic applications, due to the ratio of its anatase and rutile crystal structures, and the photocatalytic effect is known to provide, for example, self-cleaning properties in inorganic compositions.

[0003] Teruhisa Ohno, Koji Sarukawa, Kojiro Tokieda, Michio Matsumura, Morphology of a TiO2 Photocatalyst (Degussa, P-25) Consisting of Anatase and Rutile Crystalline Phases, Journal of Catalysis, Volume 203, Issue 1, 2001, Pages 82-86

[0004] Known TiO ２ However, TiO is difficult to disperse in an aqueous polymer solution and tends to aggregate. ２ Even if a coating film or the like is formed using a polymer aqueous solution containing TiO ２ Therefore, it was difficult to use the coating film as a thermal conductive material. ２ It is conceivable to add a dispersant to improve the dispersibility of the polymer. However, the presence of the dispersant may reduce desired properties, such as thermal conductivity. Furthermore, there is also the problem of the dispersant bleeding out.

[0005] The present disclosure has been made in view of the above circumstances, and an object of the present disclosure is to provide a novel composite material that has high dispersibility and is suitable for producing films and the like with desired properties.

[0006] According to one aspect of the present disclosure, a compound of the formula: ａ O ｂ (wherein M is at least one element selected from the group consisting of Groups 3, 4, 5, 6, and 7; Q is at least one element selected from the group consisting of Groups 12, 13, 14, 15, and 16 (excluding O); a is 0 or more and 2 or less; and b is 0 or more and 2 or less), and a composite material is provided, the composite material comprising: a material containing nanofibers and / or two-dimensional substances represented by the formula:

[0007] According to the present disclosure, a novel composite material is provided that contains a predetermined material and a resin and has high dispersibility of the predetermined material.

[0008] Conventional TiO as a filler ２ FIG. 5 is an explanatory diagram showing the fracture of a polymer composite containing particles of MQO of the present embodiment as a filler when pulled. FIG. 6 is an explanatory diagram showing the fracture of a polymer composite containing particles of MQO of the present embodiment as a filler. FIG. 7 is a diagram showing the results of Raman spectroscopy analysis of a material (TiCO) produced in an example. FIG. 8 is an XRD pattern of a material (TiCO) produced in an example. FIG. 9 is an XRD pattern of a material (TiCO / polyurethane composite material) produced in an example. FIG. 10 is a diagram in which the XRD patterns of FIG. 4 and FIG. 11 are superimposed. ２ 1 shows the results of evaluating the dispersibility of a water dispersion of titanium dioxide (TiO ２ 1 shows the results of evaluating the dispersibility of an aqueous polyurethane solution dispersion of a material (TiCO) produced in a comparative example. 2 shows the results of evaluating the dispersibility of a poly(ethyleneimine) dispersion of a material (TiCO) produced in an example. 3 shows the results of evaluating the dispersibility of an aqueous polyurethane solution dispersion of a material (TiCO) produced in an example. 4 shows the results of evaluating the dispersibility of an aqueous acrylic resin solution dispersion of a material (TiCO) produced in an example.

[0009] [Composite Material] This embodiment relates to a composite material including a material containing predetermined nanofibers and / or two-dimensional materials. In this disclosure, the simple term "material" refers to a "material containing nanofibers and / or two-dimensional materials" (in other words, a material containing at least one of nanofibers and two-dimensional materials). In this embodiment, a material containing nanofibers and / or two-dimensional materials typically refers to a material that is solid and does not contain a binder or the like (e.g., a polymer). In a narrower sense, a material containing nanofibers and / or two-dimensional materials can refer to a material that is substantially composed of at least one of nanofibers and two-dimensional materials (which may include other objects, impurities, etc. that may be unavoidably mixed in). However, materials containing nanofibers and / or two-dimensional materials are not limited to these.

[0010] (MQO-containing material) The material contained in the composite material of this embodiment is a nanofiber and / or two-dimensional material of a predetermined material (substance). The predetermined material that can be used in this embodiment is represented by the following formula (1): MQO ａ O ｂ ... (1) (In the formula, M is at least one element selected from the group consisting of Groups 3, 4, 5, 6 and 7, and may include at least one element selected from the group consisting of so-called early transition metals, for example, Sc, Ti, Zr, Hf, V, Nb, Ta, Cr, Mo and Mn, and preferably at least one element selected from the group consisting of Ti, V, Cr, Mo and Mn; Q is at least one element selected from the group consisting of Groups 12, 13, 14, 15 and 16 (excluding O), and may include at least one element selected from the group consisting of B, C, N, Si, P and S; a is 0 or more and 2 or less; and b is 0 or more and 2 or less.)

[0011] The above-mentioned predetermined material will be hereinafter also referred to simply as "MQO." Examples of MQO include TiO ２ , TiCO, TiCON, VO ２ , VCO, VCON, CrO ２ , CrCO, CrCON, MoO２ , MoCO, MoCON, MnO ２ , MnCO, MnCON, and the like. For example, in formula (1), M may be Ti and Q may be C. Also, for example, in formula (1), a may not be 0. That is, a may be greater than 0, for example, 1 or greater.

[0012] MQO has a crystal structure different from the hexagonal system. Although the present embodiment is not bound by any theory, the crystal structure of MQO is currently considered to be anatase type, lepidocrocite type, or a mixture of these. For example, the crystal structure of MQO may be lepidocrocite type.

[0013] MQO can be produced, for example, using a first raw material and a second raw material as follows: The first raw material contains at least M, and the second raw material contains at least Q, and the first raw material and the second raw material are capable of reacting in a protic solvent to produce MQO.

[0014] As the first raw material, a material represented by the following formula (2) can be used: M ｃ A １ ｄ ... (2) (wherein M is as defined above, A １ is at least one element selected from the group consisting of Groups 12, 13, 14, 15, and 16, and may include, for example, at least one element selected from the group consisting of B, C, N, O, Si, P, and S; and c and d are each independently 1 to 5. However, the material represented by formula (2) must be different from the product MQO. The material represented by formula (2) may typically have no peak in its X-ray diffraction (XRD) pattern in a diffraction angle 2θ range of 2° to 12°.

[0015] Examples of the first raw material represented by formula (2) include TiB ２ , TiB, TiC, TiN, TiO ２ , Ti ５ Si ３ , Ti ２ SbP, VO２ , V ２ O ４ , NbC, Nb ２ O ５ , MoO ２ , MoO ３ , MoS ２ , MnO ２ , Mn ３ O ４ , MnCO ３ MnO that can be used as the first raw material ２ In the XRD pattern, the material has a peak near 2θ=13° and no peak in the 2θ range of 2° or more and 12° or less.

[0016] Alternatively, or in addition to the above, a material represented by the following formula (3) (hereinafter also simply referred to as a "MAX phase" or "MAX raw material") may be used as the first raw material. ｍ A ２ X ｎ ...(3) (wherein M is as defined above, X is at least one element selected from the group consisting of C and N, n is 1 or more and 4 or less, m is greater than n and 5 or less, A ２ is at least one element selected from the group consisting of Groups 12, 13, 14, 15 and 16, and is usually a Group A element, typically Group IIIA and Group IVA, and more particularly may include at least one element selected from the group consisting of Al, Ga, In, Tl, Si, Ge, Sn, Pb, P, As, S and Cd, preferably Al). The MAX phase is ｍ X ｎ (which may have a crystal lattice where each X is located in an octahedral array of M), ２ The MAX phase has a crystal structure in which layers composed of atoms are located. When m=n+1, typically, one layer of X atoms is located between each of n+1 layers of M atoms (collectively referred to as "M ｍ X ｎ layer), and the layer next to the n+1-th layer of M atoms is A ２ Atomic layer ("A ２ The MAX phase has repeating units arranged in "atomic layers." However, the MAX phase is not limited to this.

[0017] Examples of the first raw material represented by formula (3) include Ti ３ AlC ２ , Ti ３ GaC ２ , Ti ３ SiC ２ These include:

[0018] As the first raw material, the material represented by formula (2) and the material represented by formula (3) may be used together (for example, as a mixture).

[0019] As the second raw material, an ionically bondable substance having a carbon-containing group can be used. The ionically bondable substance having a carbon-containing group contains C. Examples of the ionically bondable substance include ammonium salts, phosphates, sulfates, etc.

[0020] More specifically, a quaternary ammonium salt may be used as the second raw material. Examples of quaternary ammonium salts include tetramethylammonium hydroxide (TMAH), tetraethylammonium hydroxide (TEAH), tetrapropylammonium hydroxide (TPAH), tetrabutylammonium hydroxide (TBAH or TBAOH), benzyltrimethylammonium hydroxide, tetrabutylammonium fluoride (TBAF), tetrabutylammonium chloride (TBACl), tetrabutylammonium bromide (TBAB), tetrabutylammonium iodide (TBAI), benzyltriethylammonium chloride (BTEAC), hexadecyltrimethylammonium bromide, cetyltrimethylammonium bromide (CTAB), benzethonium chloride, benzalkonium chloride, and cetylpyridinium chloride (CPC). Among these, TMAH and TBAOH are preferred.

[0021] Alternatively, or in addition to the above, other ion-binding substances containing P and / or S, etc. may be used as the second raw material.

[0022] The protic solvent may be any solvent capable of at least partially dissolving the first and second raw materials, and may be, in particular, an aqueous solvent. Examples of the protic solvent include water, alcohol (e.g., ethanol, 1-propanol, isopropanol), and carboxylic acids (e.g., acetic acid and formic acid). The aqueous solvent may be composed of water and, optionally, a liquid substance compatible with water (e.g., a protic solvent other than water), and is preferably water.

[0023] The first and second raw materials are reacted in a protic solvent. The second raw material can be added to the protic solvent in advance. The ratio of the second raw material to the total of the protic solvent and the second raw material can be, for example, 5% by mass or more, particularly 20% by mass or more, and / or, for example, 80% by mass or less, particularly 50% by mass or less. The first raw material can be further added to the protic solvent to which the second raw material has been added, and mixed. In this mixture, a reaction to produce MQO proceeds. The temperature (reaction temperature) of the mixture (which may contain the reaction product) can be, for example, 15°C or more, particularly 40°C or more, and / or, for example, 100°C or less, particularly 80°C or less. The mixing time (reaction time) can be, for example, one day or more, particularly two days or more, and / or, for example, 10 days or less, particularly 7 days or less. Mixing can be performed, for example, by rotating a magnetic stirrer placed in a container while maintaining the reaction temperature using a hot plate stirrer and a warm water bath. However, the treatment operations and conditions (temperature, time, etc.) that can cause the reaction to proceed are not limited to those described above, and may be selected appropriately depending on the first raw material, second raw material, protic solvent, etc. that are used.

[0024] The above reaction produces MQO, which may eventually grow into MQO nanofibers and further MQO nanoflakes. While not limiting the present disclosure, the resulting MQO nanofibers may be in the form of nanoribbons extending in nanoscale widths. Alternatively, multiple MQO nanofibers (e.g., nanoribbons) may bond and / or integrate with each other to grow into two-dimensionally extending nanoflakes. Alternatively, multiple MQO nanoflakes may overlap each other (e.g., by van der Waals forces) to form stacks. While the present disclosure is not bound by any theory, the production and growth of MQO may be thought of as a bottom-up synthesis reaction.

[0025] In the present disclosure, the cross-sectional outer dimension of an MQO nanofiber refers to the shortest distance passing through the center of a cross section transverse to the longitudinal direction of the MQO nanofiber. The cross-sectional shape of an MQO nanofiber is not particularly limited, but can be approximated, for example, by a rectangle (rectangle, square, etc.) or an ellipse (flattened circle, perfect circle, etc.). When an MQO nanofiber is in the form of a nanoribbon, the cross-sectional shape can be approximated by a rectangle, and the cross-sectional outer dimension can correspond to the length of the short side of the rectangle. When an MQO nanofiber is in the form of a nanofilament, the cross-sectional shape can be approximated by a flattened circle, and the cross-sectional outer dimension can correspond to the length of the short diameter of the flattened circle.

[0026] In the present disclosure, MQO is a solid content. MQO may typically be in the form of particles (or powder).

[0027] The mixture after the reaction (also referred to as a reaction mixture) may be subjected to appropriate post-treatment, such as washing, impact (including shear force), drying (e.g., freeze-drying or heat drying), or pulverization.

[0028] The washing may be carried out using a protic solvent. The same explanation as above may be applied to the protic solvent, and the protic solvent may be washed with, for example, water or alcohol. After washing, a separation operation (centrifugation and / or decantation) may be carried out. The washing and separation operations may be repeated until the pH of the supernatant after centrifugation is, for example, 8 or less.

[0029] Optionally, instead of or in addition to the above washing, washing may be carried out using an aqueous solution of a metal salt. The metal salt may be, for example, a halide (fluoride, chloride, bromide, iodide) of an alkali metal (Li, Na, K, etc.), typically LiCl, NaCl, KCl, etc. Specifically, washing may be carried out using, for example, an aqueous solution of a metal salt having a molar concentration of 1 to 10. After washing, a separation operation (centrifugation and / or decantation) may be carried out. In this case, too, the washing and separation operations may be repeated as necessary until the pH of the supernatant after centrifugation becomes, for example, 8 or less.

[0030] Impact such as vibration and / or ultrasound may be applied during and / or after washing. This can promote the dispersion of MQO particles (e.g., nanofibers / nanoflakes, hereinafter the same). If the MQO particles are aggregated, they can be broken down. This effect is particularly pronounced when impact is applied during washing with an aqueous solution of a metal salt (it is believed that metal cations derived from the metal salt penetrate into the gaps between the aggregates and break them down). Impact can be applied using, for example, one or more of a handshake, an automatic shaker, a mechanical shaker, a vortex mixer, a homogenizer, an ultrasonic bath, etc.

[0031] Since the MQO particles are a solid component, a separation operation can be carried out at any appropriate time to remove unnecessary liquid components, if any. As a final separation operation, for example, a drying operation, typically freeze-drying or thermal drying, may be carried out. Freeze-drying can be carried out, for example, by freezing a mixture containing the MQO particles and a liquid component at any appropriate temperature (e.g., −40° C.) and then drying under reduced pressure. Thermal drying can be carried out, for example, by drying a mixture containing the MQO particles and a liquid component at a temperature of 25° C. or higher (e.g., 200° C. or lower) under atmospheric pressure or under reduced pressure. Pulverization can be carried out using, for example, a mortar and pestle combination, an IKA mill, or the like, without particular limitation. Pulverization may also be carried out after drying.

[0032] To obtain a material containing MQO (a specific nanofiber and / or two-dimensional substance, typically MQO particles; hereinafter, this may be referred to as the "MQO-containing material") with higher purity, it is preferable to repeat washing and centrifugation multiple times and recover the supernatant after the final centrifugation. This supernatant can be used as is, appropriately diluted with a liquid medium, or dried and then mixed with a liquid medium to form a slurry containing MQO particles. This slurry can be used to produce a film, which can then be used as the composite material of this embodiment.

[0033] As a result, MQO particles can be obtained as an MQO-containing material. MQO is represented by formula (1), but the MQO-containing material (typically, MQO particles) does not necessarily have to consist solely of the constituent elements of formula (1). While not limiting the present disclosure, the MQO-containing material may optionally have at least one type of modification or terminal T present on its surface selected from the group consisting of hydroxyl groups, chlorine atoms, oxygen atoms, hydrogen atoms, and nitrogen atoms. Furthermore, the MQO-containing material (typically, MQO particles) may have two or more layers, and at least one type selected from the group consisting of ammonium ions (e.g., quaternary ammonium cations) and metal cations (e.g., alkali metal ions, alkaline earth metal ions) may be present between these layers.

[0034] The particle size of the MQO particles may be, for example, 0.01 nm or more, in particular 0.1 nm or more, or even 1 nm or more, and / or may be, for example, less than 1000 nm, in particular 100 nm or less, or even 50 nm or less. Such particles may also be referred to as nanoparticles.

[0035] The particle form of MQO is nanofibers and / or two-dimensional materials. The two-dimensional materials include one or more of nanoflakes and stacks of nanoflakes. In this embodiment, the two-dimensional materials are not limited to only nanoflakes and stacks of nanoflakes.

[0036] Nanofibers may also be referred to as nanowires. In the present disclosure, "nanofiber" refers to a solid object extending in the longitudinal direction, the cross-sectional dimensions of which perpendicular to the longitudinal direction (cross-sectional external dimensions) are on the nano-order (i.e., 1 nm or more and less than 1000 nm) or even smaller, sub-nano-order (less than 1 nm, for example, 0.1 nm or more and less than 1 nm). The longitudinal length of a nanofiber is not limited to the nano-order (i.e., 1 nm or more and less than 1000 nm), but may also be on the micron order (1 μm or more and less than 1000 μm). The cross-sectional external dimensions of a nanofiber may be, for example, 0.1 nm or more, particularly 1 nm or more, and may be, for example, 100 nm or less, particularly 50 nm or less, and preferably 15 nm or less.

[0037] In the present disclosure, the term "two-dimensional material" refers to a solid object having a two-dimensionally extending surface (also referred to as a plane or two-dimensional sheet surface) and a thickness that is relatively small compared to the maximum dimension of the surface (which may correspond to the "in-plane dimension" of a particle), with the thickness being on the nano-order (i.e., 1 nm or more but less than 1000 nm) or even smaller, on the sub-nano-order (less than 1 nm, for example, 0.1 nm or more but less than 1 nm). The in-plane dimension is not limited to the nano-order (i.e., 1 nm or more but less than 1000 nm) and may be on the micron-order (1 μm or more but less than 1000 μm). As described above, two-dimensional materials include one or more of nanoflakes and stacks of nanoflakes. Nanoflakes may also be referred to as nanosheets or two-dimensional (nano)sheets. The thickness of one layer of nanoflakes may be, for example, 0.01 nm or more, particularly 0.8 nm or more, and may be, for example, 20 nm or less, particularly 3 nm or less. The in-plane dimensions of the nanoflakes may be, for example, 0.1 μm or more, in particular 1 μm or more, and may be, for example, 200 μm or less, in particular 40 μm or less. The nanoflakes may be composed of an aggregate of nanofibers.

[0038] The stack of nanoflakes may also be referred to as a multi-layer MQO. The distance (interlayer distance or gap size) between two adjacent nanoflakes (or two adjacent layers of MQO) is not particularly limited.

[0039] Each of the above dimensions can be determined as a number-average dimension (number average of at least 40 dimensions) based on a photograph observed with a scanning electron microscope (SEM), a transmission electron microscope (TEM), or an atomic force microscope (AFM) (after processing by a method such as focused ion beam (FIB) if necessary), or as a distance in real space calculated from the position in reciprocal lattice space of the (002) plane measured by X-ray diffraction (XRD).

[0040] However, it should be noted that the MQO in the present disclosure is not limited to the above-mentioned form and may have any suitable form. Also, it should be noted that the composite material of the present embodiment may have any suitable form as long as it contains an MQO-containing material and a resin having a negative zeta potential.

[0041] The MQO-containing material may typically have a peak in an X-ray diffraction (XRD) pattern where the diffraction angle 2θ is in the range of 2° to 12° inclusive. Although the present disclosure is not bound by any theory, it is believed that the MQO-containing material having a peak in an XRD pattern where 2θ is in the range of 2° to 12° inclusive means that the MQO has a crystal structure different from that of well-known metal oxides.

[0042] In the present disclosure, an XRD pattern is a pattern (the vertical axis represents intensity and the horizontal axis represents 2θ) obtained by scanning in the θ-axis direction with an XRD analyzer using CuKα radiation (approximately 1.54 Å) as characteristic X-rays, and may also be referred to as an “XRD profile.” Peaks in an XRD pattern can be identified visually or by using software used with the XRD analyzer.

[0043] Although this embodiment is not limited to this embodiment, the material of this embodiment (more specifically, MQO) has a Raman shift of at least 275 to 295 cm in a Raman spectrum using a laser with a wavelength of 514 nm. －１ , 435-455cm －１ , and 665-745 cm －１ It may have a peak at the position

[0044] Although this embodiment is not limited thereto, the material of this embodiment (more specifically, MQO) has, for example, an anatase type or a lepidocrocite type crystal structure, or a mixture of these. More preferably, it has a lepidocrocite type crystal structure.

[0045] Although this embodiment is not limited to this embodiment, the material of this embodiment (more specifically, MQO) has a Raman shift of at least 275 to 295 cm in a Raman spectrum using a laser with a wavelength of 514 nm. －１ , 435-455cm －１ , and 665-745 cm －１ and when the intensities of the respective peaks are X, Y, and Z, X is the largest.

[0046] Although this embodiment is not limited thereto, more preferably, the material of this embodiment (more specifically, MQO) has a Raman shift of at least 180 to 200 cm in a Raman spectrum using a laser with a wavelength of 514 nm. －１ , 275-295cm －１ , 375-395cm －１ , 435-455cm －１ , and 665-745 cm －１ and when the intensities of the respective peaks are V, X, Y, Z, and W, X is the largest.

[0047] In this disclosure, the Raman spectrum is measured with a Raman spectrometer using a 514 nm laser as an excitation light source (the vertical axis represents intensity, and the horizontal axis represents Raman shift). Peaks in the Raman spectrum can be identified visually or by using software used with the Raman spectrometer.

[0048] Although not limiting the present embodiment, the material of the present embodiment (more specifically, MQO) is believed to have anionic ends, such as O-ends and OH-ends, on the surface of the material, and is known to dissociate protons and counter cations in a solvent such as water, thereby becoming negatively charged. The fact that the surface is negatively charged can be confirmed, for example, by measuring the zeta potential of a liquid in which MQO is dispersed in water, and finding a negative potential.

[0049] The MQO-containing material may also contain unreacted first and / or second raw materials as impurities, and may also contain substances derived from the first, second, and / or protic solvents. For example, when a quaternary ammonium salt is used as the second raw material, N may be present (residual) in any form in the MQO-containing material. While not limiting this embodiment, the MQO-containing material may contain ammonium ions or tetramethylammonium ions. Furthermore, when a MAX raw material is used as the first raw material, the MQO-containing material may contain a relatively small amount of residual A atoms, for example, 10% by mass or less relative to the original A atoms, in the present disclosure. The amount of residual A atoms may preferably be 8% by mass or less, more preferably 6% by mass or less. However, even if the amount of residual A atoms exceeds 10% by mass, this may not be a problem depending on the use conditions, etc.

[0050] The composite material of this embodiment includes the MQO-containing material and a resin with a negative zeta potential. By including the resin with a negative zeta potential, the negatively charged material of this embodiment (the MQO-containing material) and the resin with a negative zeta potential are electrostatically repulsed, as described above, to maintain high dispersibility of both materials. Furthermore, the fluidity of the slurry is maintained, enabling film formation by, for example, a spraying method.

[0051] The composite material may be in the form of a fluid, including a liquid, or a solid.

[0052] When the composite material is a fluid material, it includes an MQO-containing material (e.g., MQO particles), a resin with a negative zeta potential, and a liquid medium. The resin may be, for example, a water-soluble polymer. The composite material (fluid material) of this embodiment may be an aqueous dispersion, slurry, paste, or the like, in which the MQO-containing material is dispersed in a mixed medium of a water-soluble polymer and a liquid medium. Regardless of the form of the fluid material, the MQO particles of this embodiment have high dispersibility and therefore disperse well in the mixed medium without agglomeration. For example, the mixed medium may be an aqueous polymer solution containing a water-soluble polymer in an amount greater than 0% by mass and not more than 20% by mass, preferably not more than 10% by mass, relative to the total of the water-soluble polymer and the liquid medium (e.g., water). Examples of the water-soluble polymer include polymers (resins) with a negative zeta potential, such as alkyl polymers, polymers having amide bonds (—NHCO—), polymers having urethane bonds, polymers having ester bonds, polymers having ether bonds, and acrylic polymers (acrylic resins). In this embodiment, these resins contain one or more anionic functional groups and anionic segments. They are known to dissociate protons and countercations in solvents such as water, becoming negatively charged. Because MQO is negatively charged, electrostatic repulsion with the negatively charged polymer results in a composite material in which both are dispersed. Examples of anionic functional groups include hydroxyl groups, hydroxyl bases, carboxyl groups, carboxyl bases, sulfonic acid groups, sulfonate bases, phosphate groups, phosphate bases, and thiol groups. Examples of the polymer include polyvinyl alcohol, polyethylene glycol, polyacrylic acid, polyacrylates, poly(vinylphosphonic acid), poly(vinylphosphonate), polymers containing oxoacids (e.g., polyphosphoric acid) as repeating units, polyvinyl sulfonic acid, and polyvinyl sulfonate. The anionic functional groups and anionic segments in the polymer may be 50 mol% or less. Examples include self-emulsifying resins with anionic functional groups and anionic segments, including amide or urethane bonds, and acrylic resins.Examples of resins having an amide bond or a urethane bond include polyamideimide (PAI), polyacrylamide (PMA), nylon (polyamide resin), DNA (deoxyribonucleic acid), acetanilide, and acetaminophen. Examples of acrylic resins include polymers polymerized from monomers having an acrylic group, such as monofunctional acrylates such as methyl (meth)acrylate, ethyl (meth)acrylate, propyl (meth)acrylate, isopropyl (meth)acrylate, isobutyl (meth)acrylate, t-butyl (meth)acrylate, and 3-hydroxyethyl (meth)acrylate, and bifunctional acrylates such as ethylene glycol di(meth)acrylate, propylene glycol di(meth)acrylate, and butylene glycol di(meth)acrylate. Examples of the polymers include alkyl polymers having an acrylic group at at least one end, polymers having an ether bond, and polymers having reactive functional groups, such as hydroxyl groups, carboxyl groups, amino groups, epoxy groups, mercapto groups, and oxazoline groups, on the side chains of these polymers. The resin is preferably one or more of a resin having an amide bond or a urethane bond, and an acrylic resin.

[0053] As the liquid medium, an organic medium may be used instead of water or as a mixture with water. Examples of the organic medium include acetonitrile, N,N-dimethylacetamide, N,N-dimethylformamide, DMSO, DMF, NMP, acetone, 2-methyl-2-propanol, isopropyl alcohol, ethanol, and methanol.

[0054] The proportion of the MQO-containing material in the fluid composite material can be appropriately set depending on the application, and may be, for example, 0.1 mass % or more and 99.9 mass % or less.

[0055] When the composite material is a solid material, it may be a composite material containing an MQO-containing material and a resin (polymer) with a negative zeta potential. Examples of the polymer (resin) with a negative zeta potential include alkyl polymers, polymers with amide bonds (—NHCO—), polymers with urethane bonds, polymers with ester bonds, polymers with ether bonds, and acrylic polymers (acrylic resins). In this embodiment, these resins contain one or more anionic functional groups and anionic segments, and are known to dissociate protons and countercations in solvents such as water, thereby becoming negatively charged. Because MQO is negatively charged, electrostatic repulsion between MQO and the negatively charged polymer results in a composite material in which both are dispersed. Examples of anionic functional groups include hydroxyl groups, hydroxyl bases, carboxyl groups, sulfonic acid groups, sulfonate groups, phosphate groups, phosphate bases, and thiol groups. Examples of the polymer include polyvinyl alcohol, polyethylene glycol, polyacrylic acid, polyacrylates, poly(vinylphosphonic acid), poly(vinylphosphonates), polymers having oxoacids (typically polyphosphoric acid) as repeating units, polyvinyl sulfonic acid, polyvinyl sulfonates, etc. The anionic functional groups and anionic segments in the polymer may be 50 mol% or less, and may be, for example, a self-emulsifying resin having an anionic functional group and an anionic segment, an amide bond or a urethane bond, or an acrylic resin. Examples of the resin having an amide bond or a urethane bond include polyamideimide (PAI), polyacrylamide (PMA), nylon (a polyamide resin), DNA (deoxyribonucleic acid), acetanilide, and acetaminophen.Examples of acrylic resins include polymers polymerized from monomers having an acrylic group, such as monofunctional acrylates such as methyl (meth)acrylate, ethyl (meth)acrylate, propyl (meth)acrylate, isopropyl (meth)acrylate, isobutyl (meth)acrylate, t-butyl (meth)acrylate, and 3-hydroxyethyl (meth)acrylate, and bifunctional acrylates such as ethylene glycol di(meth)acrylate, propylene glycol di(meth)acrylate, and butylene glycol di(meth)acrylate. Other examples include alkyl polymers having an acrylic group at at least one end, polymers having an ether bond, and polymers having reactive functional groups such as hydroxyl groups, carboxyl groups, amino groups, epoxy groups, mercapto groups, and oxazoline groups in the side chains of these polymers. The resin is preferably one or more of a resin having an amide bond or a urethane bond, and an acrylic resin.

[0056] The proportion of the polymer in the solid composite material can be determined in consideration of the desired properties, and can be, for example, 0.1% by mass or more and 99.9% by mass or less.

[0057] The proportion of the MQO-containing material in the solid composite material can be appropriately set depending on the application, and may be, for example, 0.1 mass % or more and 99.9 mass % or less.

[0058] The MQO-containing material according to this embodiment has high dispersibility, and is therefore well mixed with the polymer, resulting in a polymer composite in which the MQO-containing material is well dispersed without aggregation. The MQO-containing material and polymer can be stirred using a dispersing device such as a homogenizer, a propeller stirrer, a thin film rotary stirrer, a planetary mixer, a mechanical shaker, a vortex mixer, or a high-pressure disperser.

[0059] When the composite material of this embodiment is solid, it may be, for example, in the form of a film. A film-like composite material can be formed using, for example, a slurry, which is a mixture of the MQO particles and a polymer, which is the fluid composite material. For example, a film-like composite material can be formed by applying the slurry, which is a mixture of the MQO particles and a polymer, to a substrate (e.g., a substrate). However, the application method is not limited. Examples include spray application using a nozzle such as a one-fluid nozzle, a two-fluid nozzle, or an airbrush; slit coating using a table coater, comma coater, or bar coater; screen printing; metal mask printing; and application methods such as spin coating, dipping, and dripping. The application and drying may be repeated multiple times as necessary until a film of the desired thickness is obtained. Drying and curing may be performed, for example, at a temperature of 400°C or less using an atmospheric pressure oven or a vacuum oven.

[0060] Although the present disclosure is not bound by any theory, one of the reasons why the MQO particles according to this embodiment have high dispersibility is thought to be that the negatively charged MQO particles have a large absolute value of the zeta (ζ) potential, which causes a large electrostatic repulsion with the resin, which is also negatively charged. When the zeta potential of the MQO particles is measured by the following method, the absolute value of the zeta potential of the MQO particles can be, for example, 1 or more, and preferably 10 or more. In measuring the zeta potential, ion-exchanged water is used as a dispersion medium, and the MQO particles or the TiO particles used in the comparative example are ２ The particle concentration is adjusted to 0.01 to 0.1% by mass, and the dispersion is permeated with a vortex mixer for 5 minutes. Using the dispersion, measurements are performed under atmospheric conditions using a zeta potential measuring device (Zetasizer Nano-ZS, Malvern Panalytical, Malvern, U.K.).

[0061] When the composite material of this embodiment is in the form of a film, a film with high film strength can be obtained. As shown in FIG. 1, TiO, which has conventionally been used as a filler, is ２ The polymer composite obtained by mixing the resin 1 and the resin 3 without adding a dispersant and then applying the mixture to a PET substrate 5 contains TiO ２The aggregated regions 1 are likely to form aggregated regions 7, surrounded by dashed lines (Figure 1, left). When the above polymer composite is pulled in the direction of the black arrow, for example, for measuring film strength (tensile testing), fracture failure is likely to occur starting from the aggregated regions 7, as shown in Figure 1, right. In contrast, as shown schematically in Figure 2, a polymer composite obtained by mixing a material 9 containing a predetermined nanofiber and / or two-dimensional material with a resin 3 without adding a dispersant and then applying the mixture to a PET substrate 5 allows the material 9 to be dispersed without agglomeration. While adding a dispersant during mixing with the resin shortens the service life due to degradation of the dispersant, the composite material of this embodiment does not encounter such a problem. As a result, when the film is pulled in the direction of the black arrow, for example, for measuring film strength (tensile testing), fracture is unlikely to occur and the film exhibits high strength.

[0062] Although the composite material in one embodiment has been described in detail above, various modifications of the present disclosure are possible. It should be noted that the material of the present disclosure may be manufactured by a method different from the manufacturing method in the above-described embodiment.

[0063] The present invention will be described in more detail below with reference to examples. The present invention is not limited to the following examples, and can be practiced with appropriate modifications within the scope of the above-mentioned and below-mentioned aims, and all such modifications are included in the technical scope of the present invention.

[0064] [Example 1: TiCO / Polyurethane Composite Film] [Preparation of Slurry Containing TiCO] First, titanium diboride (TiB ２1 g of tetramethylammonium hydroxide (TMAH) (manufactured by Alfa Aesar) and 10 mL of a 25% by weight aqueous solution (manufactured by Alfa Aesar) of tetramethylammonium hydroxide (TMAH) were added. A stirrer tip with a length (35 mm) approximately the same size as the inner diameter of the circular bottom of the container was placed therein. The container was maintained at 80°C in an oil bath, and the mixture in the container was stirred with the stirrer tip for 120 hours, allowing the reaction to proceed. The reaction mixture in the container was then transferred to a centrifuge tube. The solids were allowed to settle by centrifugation at 3500 G for 5 minutes using a centrifuge. (i) After centrifugation, the supernatant was discarded, (ii) 40 mL of ethanol (manufactured by Fisher Chemical) was added to the remaining sediment in the centrifuge tube, and the resulting mixture was dispersed using a vortex mixer for 5 minutes (reslurry), and (iii) centrifuged under the same conditions as above. These steps (i) to (iii) were repeated until the pH of the supernatant became 8 or less. After repeating the steps three times, the pH of the supernatant became 8 or less, so the supernatant was discarded and the repeating procedure was terminated. 40 mL of pure water was added to the remaining sediment in the centrifuge tube, and the mixture was shaken and stirred for 5 minutes using a vortex mixer. Then, the mixture was centrifuged at 3500 G for 30 minutes using a centrifuge, and the supernatant was recovered as a slurry containing TiCO as MQO.

[0065] [Analysis of the obtained TiCO] (SEM observation) The shape of the TiCO was observed by SEM. Specifically, the slurry containing TiCO prepared above was diluted 1000 times and dropped onto an Al porous substrate. Pt / Pd vapor deposition (40 mA, 30 s) was performed, and observation by SEM confirmed that nanofibers with a width of 20 nm were obtained.

[0066] (Measurement of Zeta Potential) The zeta potential of the TiCO slurry was measured to be −80 mV, which was a larger absolute value than the −0.5 mV of a conventional titanium dioxide (P-25) slurry (aqueous dispersion). Next, the zeta potential of the polymer was measured, and the values ​​were −35.5 mV for polyurethane (Rezamin D-4080 (polyether / carbonate type) manufactured by Dainichiseika Color & Chemicals Mfg. Co., Ltd.), −30.5 mV for an acrylic resin material (Aron (registered trademark) NW-400 manufactured by Toagosei Co., Ltd.), and 10.5 mV for poly(ethyleneimine) (aqueous solution of poly(ethyleneimine) manufactured by Sigma-Aldrich).

[0067] (Raman Spectroscopic Analysis) Using the TiCO slurry, a Raman spectrum was obtained by measuring with a Raman spectrometer (manufactured by Renishaw, product number: InVia) using a laser beam with a wavelength of 514 nm as an excitation light source. An example of the measurement results is shown in FIG. 3. From FIG. 3, it can be seen that the Raman shift is 275 to 295 cm －１ , 435-455cm －１ , and 665-745 cm －１ It is clear that the compound has a lepidocrocite-type crystal structure. The Raman shift is at least 180 to 200 cm －１ , 275-295cm －１ , 375-395cm －１ , 435-455cm －１ , and 665-745 cm －１ It can be seen that when the intensities of the respective peaks are V, X, Y, Z, and W, X is the largest.

[0068] (Preparation of TiCO Film) To analyze the component composition, structure, etc. of the obtained TiCO, a TiCO film was prepared using the slurry containing TiCO as follows. 1 mL of the slurry containing TiCO was dispensed and mixed with 20 mL of pure water, and then vibrated with a vortex mixer for 5 minutes. The mixture obtained was subjected to suction filtration overnight using a Nutsche filter. A membrane filter (Durapore, pore size 0.22 μm, manufactured by Merck Ltd.) was used as the filter for suction filtration. After suction filtration, the precursor film on the filter was dried overnight at 80° C. in a vacuum oven, and the filter was removed to obtain a film (freestanding film).

[0069] (X-ray Photoelectron Spectroscopy (XPS) Analysis) The obtained TiCO film (freestanding film) was analyzed by X-ray photoelectron spectroscopy (XPS). In the obtained XPS spectrum, peaks corresponding to Ti2p, C1s, O1s, and N1s were observed, and therefore Ti, C, O, and N were detected. Since N is considered to be a residue of the raw material TMAH, the material of the freestanding film is considered to be composed of Ti, C, and O.

[0070] (Measurement of XRD Pattern) The XRD pattern of the obtained film (freestanding film) was measured using an XRD device (MiniFlex, manufactured by Rigaku Corporation) (characteristic X-rays: CuKα=1.54 Å). The obtained XRD pattern is shown in FIG. 4. As can be seen from FIG. 4, this material had a peak of the (001) plane at 2θ=7.7° and a peak of the (002) plane at 2θ=15.4°. This indicates that this material has a periodic structure in the thickness direction.

[0071] [Preparation of Resin Slurry and Mixing of Resin Slurry with Slurry Containing TiCO] Polyurethane (Rezamin D-4080 (polyether / carbonate type) manufactured by Dainichiseika Color & Chemicals Mfg. Co., Ltd.) and pure water were mixed in a ratio of 1:9 and stirred for 5 minutes with a vortex mixer to obtain a resin slurry.

[0072] The resin slurry, pure water, and a slurry containing TiCO were mixed so as to obtain a TiCO / polyurethane composite material in which the ratio of polyurethane to TiCO (after film formation and drying) was 30 mass %. The mixture was stirred for 5 minutes with a vortex mixer to obtain a mixed slurry of TiCO and resin.

[0073] [Preparation of TiCO / Polyurethane Composite Film (1) Suction Filtration] The TiCO / resin mixed slurry prepared above was subjected to suction filtration overnight using a Nutsche filter. A membrane filter (Durapore, pore size 0.22 μm, manufactured by Merck Ltd.) was used as the suction filtration filter. After suction filtration, the precursor film on the filter was dried overnight at 80°C in a vacuum oven, and the filter was removed to obtain a TiCO / polyurethane composite film (a free-standing film, also referred to as a "TiCO / polyurethane composite film").

[0074] [Preparation of TiCO / Polyurethane Composite Film (2) Spray Coating] The TiCO / resin mixed slurry prepared above was spray coated onto a PET substrate using an airbrush with a spray nozzle. The spray irradiation and drying with a dryer were repeated until the film thickness of the TiCO / polyurethane composite material reached 5 μm. After coating, the film was dried in a normal pressure oven at 80°C for about 30 minutes to obtain a TiCO / polyurethane composite material film (also referred to as a "TiCO / polyurethane composite material film").

[0075] Example 2 TiCO / acrylic resin composite film A mixed slurry of TiCO and resin and a TiCO / acrylic resin composite film were obtained by spray coating in the same manner as in Example 1, except that the polyurethane in Example 1 was changed to an acrylic resin material (Aron (registered trademark) NW-400, manufactured by Toagosei Co., Ltd.).

[0076] [Comparative Example 1: TiO ２ / Polyurethane composite film] The TiCO of Example 1 was replaced with TiO ２ The same procedure as in Example 1 was repeated except that the TiO ２ and resin mixed slurry, and TiO by spray coating ２ A / polyurethane composite film was obtained.

[0077] Comparative Example 2: TiCO / poly(ethyleneimine) composite film A mixed slurry of TiCO and resin and a TiCO / poly(ethyleneimine) composite film were obtained by spray coating in the same manner as in Example 1, except that the polyurethane in Example 1 was changed to poly(ethyleneimine) (Sigma-Aldrich, aqueous poly(ethyleneimine) solution).

[0078] [Evaluation] The composite material membranes of the above examples and comparative examples were subjected to the following evaluations.

[0079] [Measurement of XRD Pattern of TiCO / Polyurethane Composite Film] The TiCO / polyurethane composite film (freestanding film) obtained by the above-mentioned "Preparation of TiCO / Polyurethane Composite Film (1) Suction Filtration" was used to measure the XRD pattern (characteristic X-ray: CuKα=1.54 Å) using an XRD device (MiniFlex, manufactured by Rigaku Corporation). The obtained XRD pattern is shown in FIG. 5. FIG. 6 shows a diagram in which this FIG. 5 and the XRD profile of FIG. 4 are superimposed. As can be seen from FIG. 5, the TiCO / polyurethane composite material had a (001) plane peak at 2θ=7.7° and a (002) plane peak at 2θ=15.5°. As shown in FIG. 6, the peak positions were not significantly different from those of the TiCO film alone, indicating that this TiCO mixed with the resin still had a periodic structure in the thickness direction.

[0080] [Evaluation of film strength] The TiCO / polyurethane composite film obtained by the above "Preparation of TiCO / polyurethane composite film (2) Spray coating", the TiCO / acrylic resin composite film obtained in the same manner, and the TiO ２ The strength of each composite film was measured by tape peeling tests using TiCO / poly(ethyleneimine) composite films as follows. Spray coating of the TiCO / poly(ethyleneimine) composite film failed due to gelation. This was likely due to the poor dispersibility of TiCO in the composite film, caused by electrostatic attraction between the negatively charged TiCO and the positively charged poly(ethylimine).

[0081] The strength of the composite film was measured in detail as follows: An adhesive tape (3M, 6122MP Scotch® Magic™ TAPE, ¾ inch wide) was attached to a portion of the upper surface of the composite film formed on the PET substrate, and then peeled off to visually check for cohesive failure of the composite film, i.e., the presence or absence of internal separation due to transfer of a portion of the composite film to the adhesive surface of the tape.

[0082] As a result, no cohesive failure was observed for the TiCO / polyurethane composite film and the TiCO / acrylic resin composite film. On the other hand, cohesive failure was observed for the titanium dioxide / polyurethane composite film. This is because the titanium dioxide (TiO ２ ) in aqueous dispersions, resulting in a poor dispersibility of titanium dioxide (TiO ２ This is thought to be due to poor dispersibility of the

[0083] [Evaluation of Thermal Conductivity] The specific heat capacity and thermal diffusivity of the TiCO / polyurethane composite film (freestanding film) obtained by the above "Preparation of TiCO / polyurethane Composite Film (1) Suction Filtration" were measured using a desktop xenon flash analyzer (instrument name: LFA 467 HyperFlash, manufactured by NETZSCH) according to the laser flash method (ASTM E1461), and the thermal conductivity was calculated. The thermal diffusivity in the in-plane direction of the flat sample was determined by pulse-heating the surface of the sample with a xenon lamp and observing the heat diffusion in the thickness direction of the portion that moved in the in-plane direction from the heated portion as the change in the temperature of the back surface of the sample over time.

[0084] As a result, the specific heat capacity (c ρ ) is 1.86 J / (g·K), and the thermal diffusivity (a) is 2.85 mm ２ / s, and the in-plane thermal conductivity (l) was 7.36 W / (m·K). For reference, the in-plane thermal conductivity of the TiCO film was also measured and found to be 8.67 W / (m·K). From this, it is considered that the composite material film according to this embodiment has well-dispersed TiCO, and therefore the decrease in thermal conductivity is suppressed even when mixed with a resin. On the other hand, titanium dioxide (TiO ２ A water dispersion of titanium dioxide (TiO) was used and subjected to suction filtration using a membrane filter, but a film (free-standing film) could not be obtained. ２ ) in an aqueous dispersion of titanium dioxide (TiO ２ This is thought to be due to the poor dispersibility of titanium dioxide (TiO) and its nanoparticle shape. TiCO is a one-dimensional material (nanofiber) and / or two-dimensional material, and is easy to form a film, whereas titanium dioxide has a particle shape, making it difficult to form a coating. ２ Since it was not possible to form a film containing ZnO), it was also not possible to evaluate the thermal conductivity of the film.

[0085] [Evaluation of Dispersibility] The present inventors separately conducted a test using titanium dioxide (TiO ２ ) aqueous dispersion (titanium dioxide concentration: 1% by mass), titanium dioxide (TiO ２A polyurethane aqueous dispersion of TiCO particles (concentration of titanium dioxide: 1% by mass, concentration of polyurethane: 1% by mass), a poly(ethyleneimine) aqueous dispersion of TiCO particles (concentration of TiCO particles: 1% by mass, concentration of poly(ethyleneimine): 1% by mass), a polyurethane aqueous dispersion of TiCO particles according to the present embodiment (concentration of TiCO particles: 1% by mass, concentration of polyurethane: 1% by mass), and an acrylic resin aqueous dispersion of TiCO particles according to the present embodiment (concentration of TiCO particles: 1% by mass, concentration of acrylic resin: 1% by mass) were placed in a glass container and left to stand. The bottoms of the glass containers were then visually inspected after being left to stand for four days. Photographs of the results are shown in FIGS. 7 to 11 . A circular white precipitate was observed in the center of the photograph in FIG. 7 , and a circular white precipitate was observed in the center of the photograph in FIG. 8 . As is clear from the photographs in FIGS. 7 and 8 , titanium dioxide had precipitated at the bottom of the glass container.

[0086] FIG. 9 is a photograph showing that TiCO2 was not sufficiently dispersed in a poly(ethyleneimine) aqueous solution and gelled. This gel sample had too high a viscosity to be spray-coated, confirming that mixing a resin with a non-negative zeta potential with TiCO2 would not provide a composite material suitable for the production of membranes and the like. In contrast, as shown in the photograph of FIG. 10 , the polyurethane aqueous solution dispersion of TiCO2(MQO) particles according to this embodiment showed no precipitation of TiCO2 particles even after four days (note that the white area at the top of the photograph in FIG. 10 is the background area that has been mixed in and is not a precipitation). It is believed that the high dispersibility of the TiCO2 particles according to this embodiment contributes to the excellent thermal conductivity and other properties of membranes containing the TiCO2 particles. Similarly, as shown in the photograph of FIG. 11 , the acrylic resin aqueous solution dispersion of TiCO2(MQO) particles according to this embodiment showed no precipitation of TiCO2 particles even after four days, demonstrating high dispersibility.

[0087] This application claims priority to U.S. Application No. 63 / 609,383, filed December 13, 2023, the entire contents of which are incorporated herein by reference.

[0088] 1 TiO ２(Filler) 3 Resin 5 PET substrate 7 Aggregation portion 9 Material containing predetermined nanofibers and / or two-dimensional substances

Claims

1. The formula: MQ ａ O ｂ (wherein M is at least one element selected from the group consisting of groups 3, 4, 5, 6, and 7; Q is at least one element selected from the group consisting of groups 12, 13, 14, 15, and 16 (excluding O); a is 0 or more and 2 or less; and b is 0 or more and 2 or less), and a composite material comprising a nanofiber and / or two-dimensional substance represented by the formula: and a resin having a negative zeta potential.

2. The composite material according to claim 1, which has a peak in an X-ray diffraction pattern at a diffraction angle 2θ in the range of 2° or more and 12° or less.

3. In the Raman spectrum using a laser with a wavelength of 514 nm, the Raman shift is 275 to 295 cm －１ , 435-455cm －１ , and 665-745 cm －１ The composite material according to claim 1 or 2, having a peak at a position 4. The composite material according to any one of claims 1 to 3, which has a crystal structure of anatase type or lepidocrocite type, or a mixture of these.

5. The composite material according to any one of claims 1 to 4, having a lepidocrocite type crystal structure.

6. In the Raman spectrum using a laser with a wavelength of 514 nm, the Raman shift is at least 180 to 200 cm －１ , 275-295cm －１ , 375-395cm －１ , 435-455cm －１ , and 665-745 cm －１ The composite material according to any one of claims 1 to 5, wherein, when the intensities of the respective peaks are V, X, Y, Z, and W, X is the largest.

7. The composite material according to any one of claims 1 to 6, wherein the resin is at least one of a resin having an amide bond or a urethane bond, and an acrylic resin.

8. A composite material according to any one of claims 1 to 7, wherein the resin accounts for 5 mass% or more of the composite material.

9. The composite material according to any one of claims 1 to 8, which is in the form of a film.

10. The composite material according to any one of claims 1 to 9, which is a heat conductive material.

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