Sns dispersion liquid and method for producing same

Abstract

[Problem] To provide: an SnS particle dispersion liquid which has fine dispersibility and in which precipitates do not appear when being preserved; a method for producing the same; and an SnS particle production method. [Solution] This SnS dispersion liquid has SnS particles dispersed in a water-based or alcohol-based dispersion liquid. In the SnS dispersion liquid, the average major axis of the dispersed SnS particles is 100-2000 nm, the average minor axis of the SnS particles is 50-1000 nm, and the average aspect ratio (major axis / minor axis) is 1.2-1.6. This method for producing an SnS dispersion liquid comprises: a vapor deposition step for heating an SnS raw material housed in an evaporation source container and capturing SnS in a capturing container; an isolation step for separating an obtained vapor deposition product from the capturing container to obtain SnS particles; and a dispersion step for dispersing the vapor deposition product obtained in the isolation step in a water-based dispersion liquid. In the vapor deposition step, the heating temperature of the evaporation source container is 700-900°C, and the maximum capturing container temperature of the capturing container is 80-130°C.

Description

SnS dispersion and method for producing same

[0001] The present invention relates to an SnS dispersion and a method for producing the same, and more particularly to an SnS dispersion and SnS particles which have good dispersibility and do not precipitate during storage, as well as a method for producing SnS particles and a method for producing an SnS dispersion.

[0002] Metal sulfides have attracted attention in various fields, such as the energy-related field and the lubricant field, and stannous sulfide (SnS) has particularly attracted attention due to its excellent properties. For this reason, various metal sulfides containing stannous sulfide with adjusted particle size and methods for producing the same have been proposed. For example, Patent Document 1 proposes a method for producing a tin sulfide film with crystals oriented in a specific direction by a vacuum plating method. Specifically, a tin sulfide film is formed on the surface of a substrate by vacuum plating at a vacuum degree of 133.3 × 10 -4 ~13.3 x 10 -7In a method for producing a tin sulfide film, a tin sulfide film is formed at a pressure in the range of Pa. This method is characterized by controlling the substrate temperature to a range of 120 to 400°C and the film formation rate to a range of 0.05 to 0.5 μm / min, thereby orienting the tin sulfide film crystals in a specific direction. Patent Document 2 proposes a method for producing tin sulfide that is industrially simple and safe, preventing contamination of the reaction system by unreacted sulfur without using special equipment such as high-pressure equipment or harmful substances such as mercury. Specifically, this method proposes a method for producing tin sulfide that comprises mechanochemically treating a workpiece containing metallic tin and sulfur, where the sulfur content relative to the metallic tin content is 1 to 4 in atomic molar ratio (S / Sn), thereby reacting the metallic tin with the sulfur to obtain tin sulfide. Patent Document 3 proposes a method for producing a powder containing stannous sulfide that is energy-efficient, efficient, and capable of continuous production. Specifically, the proposed method includes a charging step of introducing into a mill powder or lumps of tin and sulfur, in which the ratio of the number of sulfur atoms to the number of tin atoms (S / Sn) is 0.95 or more and 1.50 or less, and a processing step of operating the mill to mechanically activate the tin and sulfur, thereby causing a chain synthesis reaction due to the heat of the synthesis reaction of tin and sulfur, wherein the charging step is carried out at a temperature lower than the melting point of sulfur. Patent Document 4 proposes a production method for obtaining a high-purity chalcogenide compound of Group 14 elements and Group 16 elements in a ratio of about 1:1, which has been difficult to obtain in the past. Specifically, the proposed method includes a method for producing a high-purity chalcogenide compound of Group 14 elements and Group 16 elements in a ratio of about 1:1, which has the general formula: M １ M ２ ｘ [In the formula, M １ indicates an element in Group 14 of the periodic table. ２ indicates an element of Group 16 of the periodic table. x is 0.9 to 1.1.], and the amount of the chalcogenide compound present is 90 mol % or more as determined by X-ray diffraction measurement. A high-purity chalcogenide material and a method for producing the same have been proposed.

[0003] Japanese Patent Laid-Open No. 8-144044 Japanese Patent Laid-Open No. 2015-120607 Japanese Patent Laid-Open No. 2018-5278 WO2020 / 013191

[0004] However, the tin sulfides proposed above and the tin sulfides obtained by the manufacturing methods have not yet been able to achieve the required performance. The present inventors have conducted extensive research into the reasons why the previously proposed tin sulfides are unable to achieve the desired performance, and have found that one of the reasons is that the tin sulfides have poor dispersibility in the dispersion liquid, which is the state before use. In other words, obtaining tin sulfides with good dispersibility is important for achieving the desired performance, and a tin sulfide dispersion with good dispersibility that does not precipitate during storage is needed.

[0005] Therefore, an object of the present invention is to provide a dispersion of SnS particles that has good dispersibility and does not precipitate during storage, a method for producing SnS particles and a SnS dispersion, and a method for producing SnS particles.

[0006] As a result of extensive research aimed at solving the above problems, the present inventors discovered that the above object could be achieved by dispersing SnS particles in a dispersion produced by performing a vapor deposition process under specific temperature conditions, and thus completed the present invention. Specifically, the present invention provides the following: 1. An SnS dispersion obtained by dispersing SnS particles in an aqueous or alcoholic dispersion, wherein the dispersed SnS particles have an average major axis of 100 to 2000 nm, an average minor axis of 50 to 1000 nm, and an average aspect ratio (major axis / minor axis) of 1.2 to 1.6. 2. The SnS dispersion according to 1, wherein the concentration of the SnS particles in the aqueous dispersion is 0.0001 to 50 mass %. 3. 3. The SnS dispersion according to 1, wherein the SnS particles have an average thickness of 100 to 1,000 nm and a particle size distribution (based on scattering intensity, D50) of 100 to 700 nm. 4. The SnS dispersion according to 1, wherein the dried SnS particles have an SnS purity of 90 mass % or more as measured by XRD. 5. The SnS particles have a specific surface area of ​​5 m2 as measured by the BET method. 2 6. The SnS dispersion according to 1, wherein the mass absorption coefficient (0.001 mass%) is 15,000 cm at a wavelength of 600 nm. －１The SnS dispersion according to 1, wherein the SnS particles have an average major axis of 100 to 2000 nm, an average minor axis of 50 to 1000 nm, and an average aspect ratio (major axis / minor axis) of 1.2 to 1.6. 8. The SnS particles according to 7, wherein the average thickness of the SnS particles is 100 to 1000 nm, and the particle size distribution (scattering intensity basis, D50) of the SnS particles is in the range of 100 to 700 nm. 9. The SnS particles according to 7, wherein the dried SnS particles have an SnS purity of 90 mass % or more as measured by XRD. 10. The SnS particles have a specific surface area of ​​5 m2 or more as measured by BET measurement. 2 / g or more. 11. SnS particles according to 7, which are mixed particles of SnS and acetylene black, containing acetylene black in addition to SnS. 12. A method for producing SnS particles, comprising: a vapor deposition step of heating a SnS raw material contained in an evaporation source container to capture SnS in a capture container; and an isolation step of separating the resulting vapor from the capture container to obtain SnS particles, wherein the evaporation source container is heated to a temperature of 700 to 900°C in the vapor deposition step, and the capture container has a maximum temperature of 80 to 130°C. 13. A method for producing SnS particles according to 12, wherein the vapor deposition step has an average capture rate of 20 mg / min or more. 14. A method for producing an SnS dispersion according to 1, comprising a vapor deposition step of heating an SnS raw material contained in an evaporation source container to capture SnS in a capture container, an isolation step of separating the resulting vapor from the capture container to obtain SnS particles, and a dispersion step of dispersing the vapor obtained in the isolation step in an aqueous or alcohol-based dispersion, wherein the evaporation source container is heated to a temperature of 700 to 900°C in the vapor deposition step and the capture container has a maximum temperature of 80 to 130°C. 15. A method for producing an SnS dispersion according to 14, wherein the dispersion step comprises an ultrasonic dispersion step of performing ultrasonic dispersion at an amplitude of 50 to 150 μm.

[0007] The SnS dispersion of the present invention has good dispersibility and does not precipitate during storage. The SnS particles of the present invention constitute the above-mentioned SnS dispersion of the present invention and can exhibit excellent properties. Furthermore, according to the method for producing the SnS dispersion of the present invention, a dispersion of SnS particles having good dispersibility and not precipitating during storage can be produced. According to the method for producing SnS particles of the present invention, SnS particles constituting the above-mentioned SnS dispersion, which can exhibit excellent properties, can be obtained. The SnS particles obtained from the SnS dispersion of the present invention can exhibit excellent properties and are therefore useful as raw materials in the energy-related field, lubricant field, etc.

[0008] Fig. 1 is a schematic diagram showing a vapor deposition apparatus for carrying out a vapor deposition step in the method for producing a SnS dispersion of the present invention. Fig. 2 is an SEM photograph (a drawing substitute photograph) showing the particle state of SnS particles dispersed in the SnS dispersion obtained in Example 1. Fig. 3 is an SEM photograph (a drawing substitute photograph) showing the particle state of SnS particles dispersed in the SnS dispersion obtained in Example 2. Fig. 4 is an SEM photograph (a drawing substitute photograph) showing the particle state of SnS particles dispersed in the SnS dispersion obtained in Example 3. Fig. 5 is a drawing-substitute photograph showing the dispersion state of the SnS dispersion, where (a) shows the initial state of the SnS dispersion obtained in Example 1, (b) shows the state of the SnS dispersion obtained in Example 1 after 17 hours, (c) shows the initial state of the SnS dispersion obtained in Example 2, (d) shows the state of the SnS dispersion obtained in Example 2 after 17 hours, (e) shows the initial state of the SnS dispersion obtained in Example 3, (f) shows the state of the SnS dispersion obtained in Example 3 after 17 hours, (g) shows the initial state of the SnS dispersion obtained in the comparative example, and (h) shows the state of the SnS dispersion obtained in the comparative example after 17 hours. Fig. 6 is an SEM photograph (drawing-substitute photograph) showing the particle state of SnS particles dispersed in the SnS dispersion obtained in the comparative example. Fig. 7 is a chart showing the XRD measurement results of the SnS particles obtained in the examples and comparative examples. 8 is a photograph showing the dispersion state of the SnS dispersion, in which (a) shows the initial state of the SnS dispersion obtained in Example 4, (b) shows the initial state of the SnS dispersion obtained in Example 5, (c) shows the initial state of the SnS dispersion obtained in Example 6, (d) shows the initial state of the SnS / acetylene black dispersion obtained in Example 7, (e) shows the tin sulfide / acetylene black mixed particles obtained in Example 7, (f) shows the initial state of the dispersion obtained by redispersing the particles obtained in Example 7 in water, (g) shows the initial state of the SnS / acetylene black dispersion obtained in Example 8, (h) shows the tin sulfide / acetylene black mixed particles obtained in Example 9, and (i) shows the initial state of the dispersion obtained by redispersing the particles obtained in Example 8 in water. Fig. 9 is a chart showing the particle size distribution of the SnS particles or SnS / acetylene black particles obtained in Examples 4 to 8.10(a) to 10(d) are SEM photographs (photographs substituted for drawings) showing the particle state of the SnS / acetylene black particles dispersed in the SnS dispersions obtained in Examples 7 and 8, respectively.

[0009] The present invention will be described in further detail below. <SnS dispersion and SnS particles> The SnS dispersion of the present invention is a SnS dispersion in which SnS particles are dispersed in a water- or alcohol-based dispersion, and the average particle diameter (average of major axes) and average aspect ratio (major axis / minor axis) of the dispersed SnS particles are within specific ranges. The SnS particles of the present invention are obtained from the SnS dispersion of the present invention, and the average particle diameter (average of major axes) and average aspect ratio (major axis / minor axis) are within specific ranges. The SnS particles of the present invention are extracted (taken out) from the SnS particles constituting the above-mentioned SnS dispersion and dried,

[0010] [SnS Particles (SnS Particles of the Present Invention)] In the present invention, the SnS particles (SnS particles of the present invention) dispersed in the SnS dispersion have an average major axis of 100 to 2,000 nm, preferably 100 to 500 nm, and most preferably 100 to 200 nm. Furthermore, their average minor axis is 50 to 1,000 nm, preferably 50 to 200 nm, and most preferably 50 to 150 nm. Their average aspect ratio (major axis / minor axis) is 1.2 to 1.6. While the measurement methods for these are described in detail in the Examples, all of these can be measured using an SnS dispersion. In other words, the SnS particles of the present invention are particles whose average major axis, average minor axis, and average aspect ratio measured in the SnS dispersion fall within the above-mentioned ranges. By having the average major axis, the average minor axis, and the average aspect ratio within the above ranges, it is believed that the dispersibility in the dispersion liquid is improved, and ultimately the various performance characteristics of the SnS particles themselves are improved to the required level. The average major axis refers to the average diameter of the longest part of the particle, and the average minor axis refers to the average diameter of the shortest part of the particle. The average thickness of the SnS particles is preferably 100 to 1,000 nm, more preferably 100 to 300 nm. The particle size distribution (based on scattering intensity, D10) of the SnS particles is preferably in the range of 100 to 200 nm. The particle size distribution (based on scattering intensity, D50) of the SnS particles is preferably in the range of 100 to 700 nm, more preferably 200 to 500 nm. The particle size distribution (based on scattering intensity, D90) of the SnS particles is preferably in the range of 500 to 1,500 nm. When the average thickness and the particle size distribution (particularly D50) are within the above ranges, the dispersibility is further improved, and the required performance is further improved. 2 / g or more is preferable from the viewpoint of improving dispersibility, and 2 / g, and more preferably 8 to 15m 2 / g is most preferable. The SnS particles of the present invention can be obtained by drying SnS particles dispersed in a SnS dispersion. The purity of the resulting dried SnS particles can vary depending on the purity of the raw materials used, but the SnS purity measured by XRD is preferably 90% by mass or more, and more preferably 95 to 100% by mass. This purity can be achieved by the manufacturing method described below, thereby enabling the production of a dispersion containing particles with superior dispersibility and desired properties. The method for determining the SnS purity by XRD measurement will be described in detail in the Examples. Here, "dried" refers to a state in which the moisture content of the SnS particles extracted from the dispersion has been removed, usually to a state in which the moisture content is 0.1% by mass or less. The moisture content can be measured using conventional methods without particular limitations. The drying method can be performed using conventional methods without particular limitations, but drying can also be performed using a vacuum dryer under reduced pressure at 50 to 100°C for 1 to 10 hours. In particular, SnS particles having an average major axis of preferably 100 to 500 nm, more preferably 100 to 200 nm, an average minor axis of preferably 50 to 200 nm, most preferably 50 to 150 nm, and an average aspect ratio (major axis / minor axis) of 1.2 to 1.6 are considered to have excellent dispersibility and to be useful as materials in various fields. Furthermore, an average thickness of 100 to 300 nm and a particle size distribution (based on scattering intensity, D50) of 200 to 500 nm are particularly preferred. Such SnS particles can be obtained by extracting SnS particles from a SnS dispersion obtained through an ultrasonic dispersion step in the production method described below and drying them in a manner similar to the drying method described above. In this sense, if a method for producing a SnS dispersion includes an ultrasonic dispersion step, the method for producing the SnS dispersion can be considered to be a method for producing SnS particles. Furthermore, the SnS particles in the present invention may contain other particles. Examples of the other particles include acetylene black, carbon nanotubes, graphene, graphene oxide, graphite, silicon, silicon oxide, and silicon carbide.Here, the form of "contained" includes not only a state in which SnS particles and other particles are simply dispersed and mixed, but also a state in which each particle aggregates and the aggregates further aggregate, and a state in which each particle aggregates. In this case, the blending ratio of the other particles is preferably 99 to 70 SnS:1 to 30 other particles (weight ratio, total amount 100).

[0011] [Aqueous Dispersion] The aqueous dispersion used in the SnS dispersion of the present invention can be water or a mixture of water and a water-soluble organic solvent. As the organic solvent, alcohols such as ethanol, isopropanol (IPA), and methanol can be used, and the blending ratio is not particularly limited. [Alcohol-Based Dispersion] The alcohol-based dispersion used in the SnS dispersion of the present invention can be ethanol, isopropanol (IPA), methanol, or the like.

[0012] [SnS Dispersion] The concentration of the SnS particles (including those containing other particles) in the aqueous dispersion is preferably 0.0001 to 50% by mass, more preferably 0.0001 to 25% by mass, even more preferably 0.001 to 20% by mass, and most preferably 0.01 to 10% by mass. A concentration below this range may make it difficult to obtain the characteristics of the SnS particles, while a concentration above this range is undesirable because it may result in reduced dispersibility, resulting in particle aggregation and reduced particle performance. The absorbance of the dispersion is preferably 0.15 or more at a wavelength of 600 nm and preferably 0.1 or more at a wavelength of 1250 nm. The transmittance is preferably 70% or less at a wavelength of 600 nm. The mass extinction coefficient of the dispersion (0.001% by mass) is 15,000 cm at a wavelength of 600 nm. －１ It is preferably 50,000 to 80,000 cm －１It is more preferable that the absorbance, transmittance, and mass absorption coefficient are all measured at an SnS particle concentration of 0.001% by mass, and that they are within the above ranges from the viewpoint of improving dispersibility. The measurement method is as described in the Examples. At an SnS particle concentration of 5% by mass, the absorbance is preferably 1 or more at a wavelength of 600 nm, and preferably 0.8 or more at a wavelength of 1250 nm. The transmittance is preferably 5 or less at a wavelength of 600 nm. The mass absorption coefficient is 25 cm －１ It is preferable that the distance is 50 to 80 cm or more. －１ It is more preferable that:

[0013] <Methods for Producing SnS Dispersion and Method for Producing SnS Particles> Next, the methods for producing the SnS dispersion and SnS particles of the present invention will be described. The method for producing SnS particles of the present invention can be carried out by carrying out a vapor deposition step in which an SnS raw material contained in an evaporation source container is heated to capture SnS in a capture container, and an isolation step in which the resulting vapor is separated from the capture container to obtain SnS particles. This production method can obtain the SnS particles that constitute the SnS dispersion of the present invention described above, but particularly preferred SnS particles of the SnS particles of the present invention described above can be obtained by carrying out the following method for producing an SnS dispersion, drying the resulting SnS dispersion, and extracting (taking out) the SnS particles from the SnS dispersion. Furthermore, the method for producing the SnS dispersion of the present invention is a method for producing the SnS dispersion of the present invention described above, and can be carried out by carrying out a vapor deposition step in which the SnS raw material contained in an evaporation source container is heated to capture SnS in a capture container, an isolation step in which the resulting vapor is separated from the capture container to obtain SnS particles, and a dispersion step in which the vapor obtained in the isolation step is dispersed in an aqueous dispersion. The vapor deposition step and the isolation step are common to the method for producing SnS particles and the method for producing SnS dispersion. In other words, the method for producing SnS dispersion can be carried out by further performing the dispersion step in addition to the method for producing SnS particles. Therefore, the following description of the method for producing SnS particles also applies to the method for producing SnS dispersion.

[0014] [Raw Material] The SnS raw material used in the present invention is not particularly limited in purity as long as it is a bulk SnS raw material, but a raw material with a purity of 90% or more is preferably used.

[0015] [Vapor Deposition Process] The vapor deposition process is a process of heating a SnS raw material contained in an evaporation source container and capturing SnS in a capture container. This process can be performed using a vapor deposition apparatus shown in FIG. 1. The vapor deposition apparatus 1 shown in FIG. 1 includes a chamber 10 that can be sealed and evacuated, a heater 20 installed in the chamber 10, an evaporation source container 30, and a capture container 40. The evaporation source container 30 is configured to accommodate an evaporation source therein, and a thermometer (not shown) is installed in the evaporation source container 30 so that the temperature can be measured. The evaporation source container 30 can also be heated by the heater 20. The capture container 40 is installed a predetermined distance away from the evaporation source container 30 and is installed with a thermometer (not shown) so that the temperature can be measured. The heater, evaporation source container, and capture container can be any of those typically used in this type of vapor deposition apparatus, without any particular limitations. For example, the capture container may be made of glass such as borosilicate glass or metal such as alumina, as long as it is heat-resistant and does not denature the SnS particles to be deposited. Although not specifically shown, the chamber 10 is connected to a vacuum pump to reduce the pressure and create a vacuum, and is also equipped with a valve for returning the reduced pressure to normal pressure. A typical thermocouple or the like can be used as the thermometer (not specifically shown). The temperature measurement point is not particularly limited, but it is preferable to measure the temperature near the side of the evaporation source container to reduce the influence of the heater, and for the capture container, it is preferable to measure the temperature on the back side of the capture surface for the same reason. During the deposition process, the heating temperature of the evaporation source container 30 (measured by the thermometer) is 700 to 900°C, and the maximum capture container temperature of the capture container 40 (maximum temperature measured by the temperature anomaly) is 80 to 130°C. If these temperatures are outside these ranges, the SnS dispersion of the present invention cannot be prepared. The capture vessel 40 is installed at a predetermined distance from the evaporation source vessel 30. This distance is important in adjusting the maximum capture vessel temperature of the capture vessel 40, and needs to be changed depending on the size of the chamber 10 and the amount of SnS raw material, etc., but by adjusting this distance, the above-mentioned maximum capture vessel temperature can be adjusted.In the vapor deposition process, an average capture rate of 20 mg / min or more is preferable in terms of obtaining a better quality dispersion. The vapor deposition process ends when the SnS raw material, which is the evaporation source, in the evaporation source container 30 is used up. The pressure during the process is 5 Pa to 1×10. －5 It is preferable to maintain Pa.

[0016] [Isolation Process] The isolation process is a process in which the resulting deposition product is separated from the capture container to obtain SnS particles. Specifically, this process can be performed by mechanically peeling and collecting the SnS particles in the capture container 40. This peeling and collection can be performed using any conventional method that can be used to produce particles by vapor deposition and then isolate and collect them. This process can also be performed by recovering the SnS particles attached to the capture container in a volatile solvent such as ethanol. Obtaining an ethanol dispersion in this manner can reduce the loss of SnS particles due to scattering during collection. When mechanically peeling and collecting the SnS particles, the resulting particles can be used as is. When recovering the SnS particles using a volatile solvent, the volatile solvent can be removed and the SnS particles can be dried to obtain the SnS particles. Alternatively, an SnS dispersion can be obtained by performing the dispersion process described below.

[0017] [Dispersion Step] The dispersion step is a necessary step for carrying out the method for producing the SnS dispersion of the present invention. The SnS particles obtained as a deposit in the isolation step are introduced into the aqueous or alcohol-based dispersion, and the SnS particles are dispersed by a conventional method to obtain the SnS dispersion of the present invention. Furthermore, in the dispersion step of the present invention, an ultrasonic dispersion step can be further carried out, in which ultrasonic dispersion is performed preferably at an amplitude of 50 to 150 μm, more preferably 100 to 130 μm. The ultrasonic dispersion step can be carried out using an ultrasonic device commonly used for dispersion, such as an ultrasonic homogenizer, and the frequency can be any, but can be 20 Hz to 60 Hz. By performing the ultrasonic dispersion step with an amplitude within the above range, a SnS dispersion with better dispersibility can be obtained. Furthermore, to obtain a SnS dispersion containing the above-mentioned other particles, the obtained SnS dispersion can be further mixed with other particles, such as acetylene black particles, and the above-mentioned dispersion (and optionally the ultrasonic dispersion step) can be further carried out to obtain a SnS dispersion containing the other particles. In this case, the SnS particles obtained when the particles are extracted will contain other particles.

[0018] [Other Steps] In the present invention, in addition to the above-described vapor deposition step, isolation step, and dispersion step, other steps may be performed within the scope of the present invention. For example, since the SnS particles of the present invention described above are obtained by extracting (taking out) SnS particles constituting an SnS dispersion, a drying step must be performed in which the SnS dispersion is dried to obtain SnS particles. This drying step can be performed, for example, using a vacuum dryer to dry the SnS particles under reduced pressure at 50 to 100°C for 1 to 10 hours, although the temperature and time may vary depending on the amount of SnS particles to be dried.

[0019] The present invention will be explained in more detail below with reference to examples and comparative examples, but the present invention is not limited to these examples. [Example 1] The above-mentioned deposition process was carried out using the deposition apparatus shown in Figure 1. 13 g of bulk tin sulfide (purity: about 98%) as a raw material was placed in the deposition source container 30. The distance between the deposition source container 30 and the capture container 40 was set to 12.3 cm. Next, a vacuum pump was used to reduce the pressure in the chamber to 5 x 10 -４ The evaporation source vessel was evacuated to a pressure in the Pa range, and the temperature was raised to 900°C by a heater, and heated at 900°C for 4 hours. The maximum temperature of the capture vessel 40 was 101°C. The pressure during the treatment was 5 x 10 -３ Pa ~ 1 x 10 -４ The average capture rate measured using the above-described measurement method was 46.7 mg / min. Next, the isolation and dispersion processes were performed. First, the capture container 40 was removed from the vacuum chamber 1, and ethanol was poured into the capture container 40. SnS (hereinafter also referred to as "tin sulfide") was peeled off from the glass container to obtain a tin sulfide ethanol solution. The ethanol was removed from the resulting tin sulfide ethanol solution. The isolation process involved drying the tin sulfide ethanol solution under reduced pressure in a vacuum dryer (drying temperature 70°C for 4 hours). Pure water was added to 0.4 g of the dried tin sulfide, and the mixture was stirred using a conventional stirring method (stirring with a stirrer) to obtain 8 g of a 5% by mass tin sulfide aqueous solution (SnS dispersion of the present invention). The SnS particles in the resulting dispersion were dried to obtain SnS particles. The following tests were performed using the resulting tin sulfide. A photograph of the particle shape is shown in FIG. 2, the XRD results are shown in FIG. 7, and other results are shown in Table 1.

[0020] A precipitation test was conducted using the resulting SnS dispersion. The storage container was thoroughly stirred by hand before the precipitation test began. The precipitation test was conducted by checking the precipitation state at the start and after 17 hours. The results are shown in Figures 3(a) and (b). The following measurements were also conducted using the resulting SnS dispersion. The results are shown in Table 1. Particle size distribution measurement and zeta potential measurement: The solvent used was the same as the SnS dispersion, pure water, and the SnS dispersion was diluted to 0.001% by mass. Measurements were also conducted using the resulting SnS dispersion (concentration: 5% by mass) as is. Particle size distribution measurement was conducted using an Anton Paar particle size distribution analyzer, "Litesizer® 500." Dynamic light scattering was used to measure particle size distribution based on scattering intensity, and D10, D50, and D90 were calculated. After particle size distribution measurement, zeta potential measurement was also conducted using the same analyzer. The pH during measurement was 7. Absorbance and transmittance: Measurements were carried out using the obtained SnS dispersion (5% by mass) and the diluted solution obtained by diluting this dispersion (5% by mass) with pure water to 0.001% by mass using an ultraviolet-visible-near-infrared spectrophotometer (product name "V770") manufactured by JASCO Corporation. A quartz cell with an optical path length of 10 mm was used, and the mass absorption coefficient and transmittance were calculated using the Beer-Lambert law. The formulas are shown below. Mass absorption coefficient (cm -１ ) = absorbance / (tin sulfide mass fraction × cell path length (cm)) transmittance (%) = 10 -(吸光度)　×100 The results are shown in Table 1. A small amount of the obtained SnS dispersion was dropped onto a measurement substrate. This was heated at 70°C for 4 hours under reduced pressure to remove moisture, yielding tin sulfide particles. Figure 2 shows an image of the tin sulfide particles taken with a field-emission scanning electron microscope / transmission electron microscope "FE-SEM" (JEOL JSM-6500F), and Table 1 shows the major axis A and minor axis B dimensions of the tin sulfide particles determined from the image. The thickness L dimension was measured using a laser microscope (Keyence Corporation, product name "KEYENCE VK-9700"). Note that A and B were determined by visually detecting approximately 50 particles from the image and averaging them. The SnS dispersion was dried under reduced pressure in a vacuum dryer. The drying temperature was set to 70°C, and the drying time was approximately 4 hours. After drying was completed, the tin sulfide (SnS) powder of the present invention was obtained. The obtained tin sulfide powder was identified using an X-ray diffractometer "XRD" (trade name "Empyrean" manufactured by Malvern Panalytical). The measurement results are shown in Figure 7. As a result, no peaks other than tin sulfide were detected, and the tin sulfide purity was determined to be 99% by mass or more. Next, the specific surface area (specific surface area / pore distribution measuring device "BELSORP-max" manufactured by Microtrac-Bell Corporation) was measured using the BET measurement method. The results are shown in Table 1.

[0021] Comparative Example: The amount of bulk tin sulfide (purity approximately 98%) was 1.7 g, the heating temperature was 900°C for 3 hours, and the distance between the capture container 40 and the evaporation source container 30 was 3.8 cm. The deposition was carried out in the same manner as in Example 1, except that the maximum temperature of the capture container 40 was 199°C. Furthermore, a dispersion step was carried out in the same manner as in Example 1, to obtain a SnS dispersion. The obtained SnS particles and SnS dispersion were subjected to the same tests and measurements as in Example 1. The results are shown in Figures 5, 6, and 7 and Table 1.

[0022] Example 2: An SnS dispersion was prepared in the same manner as in Example 1, except that in the dispersion step, in addition to normal stirring, the following ultrasonic dispersion step was performed, and various tests and measurements were carried out. Ultrasonic dispersion step: Using an ultrasonic homogenizer (QSONICA ultrasonic homogenizer, product name "Q125"), the obtained 5 mass% SnS dispersion was dispersed for 50 minutes at a frequency of 20 kHz and an amplitude of 60 μm. The results are shown in Figures 3, 5, and 7 and Table 1. Example 3: An SnS dispersion was obtained in the same manner as in Example 2, except that the frequency was 20 kHz and the amplitude was 120 μm. The obtained SnS dispersion was subjected to various tests and measurements in the same manner as in Example 1. The results are shown in Figures 4, 5, and 7 and Table 1.

[0023] In Table 1, "%" indicates "% by mass."

[0024] As is clear from the results shown in Figure 5, the SnS dispersion of the present invention exhibited excellent dispersibility, with no precipitation occurring even after 17 hours. On the other hand, the dispersion of the comparative example exhibited poor dispersibility, with precipitation occurring over time. Therefore, the SnS particles of the present invention exhibit such excellent dispersibility that they are believed to be able to exhibit excellent properties in a variety of applications.

[0025] Example 4: 0.8 g of dried tin sulfide obtained in the same manner as in Example 1 was added to pure water and stirred by a conventional stirring method (stirring with a stirrer) to produce 8 g of a 10 wt% aqueous tin sulfide solution (SnS dispersion). The resulting SnS dispersion was dispersed using an ultrasonic homogenizer (QSONICA ultrasonic homogenizer, product name "Q125") at a frequency of 20 kHz and an amplitude of 120 μm for 90 minutes to obtain a SnS dispersion of the present invention (the resulting dispersion is shown in Figure 8(a)). The resulting SnS dispersion was subjected to particle size distribution measurement. The solvent used was the same as the SnS dispersion, pure water, and the SnS dispersion was diluted to 0.001 wt%. The particle size distribution measurement was performed using an Anton Paar particle size distribution analyzer, "Litesizer® 500." The particle size distribution was measured based on the scattering intensity using a dynamic light scattering method, and D10, D50, and D90 were calculated. The results are shown in Table 2 and FIG.

[0026] Example 5: 1.6 g of dried tin sulfide obtained in the same manner as in Example 1 was added with pure water and stirred by a conventional stirring method (stirring with a stirrer) to produce 8 g of a 20 wt% aqueous tin sulfide solution (SnS dispersion). The resulting SnS dispersion was dispersed using an ultrasonic homogenizer (QSONICA ultrasonic homogenizer, product name "Q125") at a frequency of 20 kHz and an amplitude of 120 μm for 90 minutes to obtain a SnS dispersion of the present invention (the resulting dispersion is shown in FIG. 8(b)). The resulting SnS dispersion was subjected to particle size distribution measurement. The solvent used was the same as the SnS dispersion, pure water, and the SnS dispersion was diluted to 0.001 wt% for measurement. The particle size distribution measurement was performed using an Anton Paar particle size distribution analyzer, "Litesizer® 500." The particle size distribution was measured based on the scattering intensity using a dynamic light scattering method, and D10, D50, and D90 were calculated. The results are shown in Table 2 and FIG.

[0027] Example 6: 1.6 g of dried tin sulfide obtained in the same manner as in Example 1 was added with isopropyl alcohol (special grade 2-propanol, manufactured by Kanto Chemical Co., Inc.), and the mixture was stirred by a conventional stirring method (stirring with a stirrer) to prepare 8 g of a 20% by mass tin sulfide isopropyl alcohol solution (SnS-IPA dispersion obtained by dispersing SnS in IPA). The resulting SnS-IPA dispersion was dispersed for 90 minutes using an ultrasonic homogenizer (QSONICA ultrasonic homogenizer, product name "Q125") at a frequency of 20 kHz and an amplitude of 120 μm, yielding a SnS dispersion of the present invention. The resulting dispersion is shown in FIG. 8(c). The resulting SnS-IPA dispersion was subjected to particle size distribution measurement. The solvent used was isopropyl alcohol, the same solvent as the SnS-IPA dispersion, and the SnS-IPA dispersion was diluted to 0.001% by mass, and measurements were performed. The particle size distribution was measured using an Anton Paar particle size distribution analyzer "Litesizer (registered trademark) 500." The measurement method used was dynamic light scattering, and the particle size distribution was measured based on the scattering intensity, and D10, D50, and D90 were calculated. The results are shown in Table 2 and Figure 9.

[0028] Example 7 The same procedure as in Example 6 was carried out to obtain a 20% by mass SnS / IPA dispersion. Separately, acetylene black (DENKA BLACK Li Li-100, powder, manufactured by Denka Co., Ltd., average particle size: 35 nm, specific surface area: 68 m) was used. ２A tin sulfide / acetylene black mixture (SnS dispersion of the present invention, SnS and acetylene black concentration: 20.8% by mass) was prepared. The acetylene black was added to a 20% by mass SnS / IPA dispersion so that the tin sulfide:acetylene black ratio was 95:5. Ultrasonic dispersion (AS ONE ultrasonic cleaner ASU-2, oscillator circuit: separate excitation type, high-frequency output: 40 W, oscillator frequency: 42 kHz) was used for one hour to prepare a tin sulfide / acetylene black mixture (SnS dispersion of the present invention, SnS and acetylene black concentration: 20.8% by mass). The results are shown in Figure 8(d). The resulting tin sulfide / acetylene black mixture was heated at 70°C for four hours under reduced pressure to remove moisture, yielding tin sulfide / acetylene black mixture particles. The resulting particles are shown in Figure 8(e). FIG. 10( a) shows an image of tin sulfide particles taken with a field emission scanning electron microscope / transmission electron microscope "FE-SEM" (JSM-6500F manufactured by JEOL, hereinafter referred to as SEM). Furthermore, a tin sulfide / acetylene black mixed dispersion was diluted to 0.01% by mass, dried in the same manner, and photographed using an SEM to confirm the dispersion state of acetylene. The results are shown in FIG. 10( b). Furthermore, particle size distribution was measured using the obtained tin sulfide / acetylene black mixed particles. Pure water was added to 0.1 g of tin sulfide / acetylene black mixed particles to prepare a 0.01% by mass aqueous dispersion, which was then measured. The particle size distribution measurement was performed using an Anton Paar particle size distribution analyzer "Litesizer (registered trademark) 500." The measurement method used dynamic light scattering, measuring particle size distribution based on scattering intensity, and calculating D10, D50, and D90. The results are shown in Table 2 and Figure 9. Pure water was added to 0.5 g of tin sulfide / acetylene black mixed particles, and the mixture was stirred using a standard stirring method (using a stirrer) to produce a 1 mass% tin sulfide / acetylene black mixed aqueous dispersion, and the dispersion state in the pure water was confirmed. The results are shown in Figure 8(f).

[0029] Example 8: The same procedure as in Example 6 was carried out to obtain a 20% by mass SnS / IPA dispersion. Acetylene black was added to the 20% by mass SnS / IPA dispersion so that the mass ratio of tin sulfide to acetylene black was 90:10. Ultrasonic dispersion and mixing were then carried out for 1 hour to produce a tin sulfide / acetylene black mixed dispersion (SnS dispersion of the present invention, SnS, and acetylene black concentration: 21.7% by mass). The resulting dispersion is shown in FIG. 8(g). Tin sulfide / acetylene black mixed particles were then obtained in the same manner as in Example 7. The resulting particles are shown in FIG. 8(h). An image of the tin sulfide / acetylene black mixed particles taken with an FE-SEM is shown in FIG. 10(c). The tin sulfide / acetylene black mixed dispersion was also diluted to 0.01% by mass, dried in the same manner, and photographed with an SEM to confirm the dispersion state of the acetylene. The results are shown in Figure 10(d). Furthermore, particle size distribution measurement was performed in the same manner as in Example 7. The results are shown in Table 2 and Figure 9. Pure water was added to 0.5 g of tin sulfide / acetylene black mixed particles, and the mixture was stirred by a normal stirring method (using a stirrer) to produce a 1 mass% tin sulfide / acetylene black mixed aqueous dispersion, and the dispersion state in the pure water was confirmed. The results are shown in Figure 8(i).

[0030] In Table 2, "%" indicates "% by mass."

Claims

1. An SnS dispersion in which SnS particles are dispersed in an aqueous or alcohol-based dispersion liquid, wherein the average major axis length of the dispersed SnS particles is 100 to 2000 nm, the average minor axis length of the SnS particles is 50 to 1000 nm, and the average aspect ratio (major axis length / minor axis length) is 1.2 to 1.6, SnS dispersion liquid.

2. The SnS dispersion liquid according to claim 1, wherein the concentration of the SnS particles in the aqueous dispersion liquid is 0.0001 to 50% by mass.

3. The average thickness of the SnS particles is 100 to 1000 nm, The SnS dispersion liquid according to claim 1, wherein the particle size distribution (scattering intensity standard, D50) of the SnS particles is in the range of 100 to 700 nm.

4. The SnS dispersion liquid according to claim 1, wherein the SnS purity by XRD measurement of the dried SnS particles is 90% by mass or more.

5. The specific surface area of the SnS particles is 5 m 2 / g or more as measured by the BET method. The SnS dispersion liquid according to claim 1.

6. The mass absorption coefficient (0.001 mass %) is 15,000 cm －１ or more at a wavelength of 600 nm, and the SnS dispersion liquid according to claim 1.

7. SnS particles extracted from the SnS dispersion liquid according to claim 1, wherein the average major axis length of the SnS particles is 100 to 2000 nm, the average minor axis length of the SnS particles is 50 to 1000 nm, and the average aspect ratio (major axis length / minor axis length) is 1.2 to 1.6, SnS particles.

8. The average thickness of the SnS particles is 100 to 1000 nm, The SnS particles according to claim 7, wherein the particle size distribution (scattering intensity standard, D50) of the SnS particles is in the range of 100 to 700 nm.

9. The SnS particles according to claim 7, wherein the SnS purity by XRD measurement of the dried SnS particles is 90% by mass or more.

10. The specific surface area of the SnS particles is 5 m 2 / g or more as measured by the BET method, the SnS particles according to claim 7.

11. The SnS particles according to claim 7, wherein the SnS particles are mixed particles of SnS and acetylene black, and further contain acetylene black in addition to SnS.

12. A vapor deposition step of heating an SnS raw material accommodated in an evaporation source container and capturing SnS in a capture container, and an isolation step of separating the obtained vapor-deposited product from the capture container to obtain SnS particles, wherein in the vapor deposition step, the heating temperature of the evaporation source container is 700 to 900 °C, and the maximum capture container temperature of the capture container is 80 to 130 °C Method for producing SnS particles.

13. In the vapor deposition step, the average capture rate is 20 mg / min or more Method for producing SnS particles according to claim 12.

14. A method for producing the SnS dispersion liquid according to claim 1, a vapor deposition step of heating an SnS raw material accommodated in an evaporation source container and capturing SnS in a capture container, and an isolation step of separating the obtained vapor-deposited product from the capture container to obtain SnS particles, A dispersion step of dispersing the vapor deposition product obtained in the above isolation step in an aqueous or alcohol-based dispersion liquid, The above vapor deposition step is a method for producing an SnS dispersion liquid in which the heating temperature of the evaporation source container is 700 to 900 °C and the maximum capture container temperature of the above capture container is 80 to 130 °C.

15. The method for producing an SnS dispersion liquid according to claim 14, wherein the above dispersion step has an ultrasonic dispersion step of performing ultrasonic dispersion with an amplitude of 50 to 150 μm.