SnS dispersion fluid and method for its preparation

Abstract

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

Description

Technical field

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

[0002] Metal sulfides have attracted attention in various fields, such as energy and lubricants, and tin(II) sulfide (SnS) has garnered particular attention due to its outstanding properties. Consequently, various metal sulfides containing tin(II) sulfide with tailored particle sizes, etc., and methods for their preparation have been proposed. For example, PTL 1 proposes a method for producing a tin sulfide film with crystals oriented in a specific direction by vacuum coating. Specifically, a method for producing a tin sulfide film has been proposed in which a tin sulfide film is deposited on a substrate surface by vacuum coating at a degree of vacuum in the range of 133.3 × 10⁻⁶. -4 up to 13.3 × 10 -7The process involves the formation of tin sulfide film crystals, characterized by the controlled substrate temperature in the range of 120 °C to 400 °C and the controlled film formation rate in the range of 0.05 µm / min to 0.5 µm / min, and the orientation of the tin sulfide film crystals in a specific direction. PTL 2 proposes a tin sulfide production process that is industrially simple and safe, does not require special equipment such as high-pressure equipment or harmful substances such as mercury, and prevents contamination of the reaction system by unreacted sulfur. Specifically, a tin sulfide production process has been proposed in which a substrate containing metallic tin and sulfur, with a molar ratio (S / Sn) of 1 to 4 on an atomic basis, is subjected to a mechanochemical treatment to react the metallic tin with the sulfur to obtain tin sulfide.PTL 3 proposes a process for the production of powder containing tin(II) sulfide, wherein the process exhibits good energy efficiency and production efficiency and is suitable for continuous production. Specifically, the proposed manufacturing process includes a feeding step of supplying tin powder and sulfur powder or lumps, where 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, into a mill, and a treatment step of operating the mill to mechanically activate the tin and sulfur and effect a chain synthesis reaction due to the heat of the synthesis reaction of tin and sulfur, wherein the feeding step is carried out at a temperature inside the mill that is lower than the melting point of sulfur.PTL 4 proposes a manufacturing process for obtaining a high-purity chalcogenide compound with a ratio of approximately 1:1 of elements from group 14 and group 16 of the periodic table, which has been difficult to achieve so far, and in particular proposes a high-purity chalcogenide material and a process for its preparation, wherein the material contains a chalcogenide compound represented by the general formula: M. 1 M 2 x [where M 1 represents an element of group 14 of the periodic table, M 2 an element of group 16 of the periodic table and x is 0.9 to 1.1] and the amount of chalcogenide compound present in an X-ray diffraction measurement is 90 mol% or more. Bibliography Patent literature PTL 1: published Japanese patent application no. H08-144044 PTL 2: published Japanese patent application no. 2015-120607 PTL 3: published Japanese patent application no. 2018-5278 PTL 4: WO 2020 / 013191 Summary of the invention: Technical problem

[0003] However, the tin sulfides produced according to the above-mentioned proposals and those obtained through the proposed manufacturing processes have not yet achieved the required performance. As a result of extensive investigations into the reasons why the previously proposed tin sulfides have not achieved the desired performance, the inventors have discovered that one of the reasons is the poor dispersibility in the dispersion liquid, which represents the state prior to the use of the tin sulfide. That is, obtaining tin sulfide with good dispersibility is essential to achieving the desired performance, and a dispersion liquid made from tin sulfide with good dispersibility and without precipitation during storage is required.

[0004] Therefore, it is an object of the present invention to provide a dispersion liquid made of SnS particles with good dispersibility and without precipitation during storage, SnS particles, a method for producing the SnS dispersion liquid and a method for producing the SnS particles. Solution to the problem

[0005] As a result of intensive research aimed at solving the above problem, the inventors discovered that the aforementioned goal can be achieved by obtaining a dispersion liquid in which SnS particles are dispersed, which are produced by carrying out a vapor deposition step under specific temperature conditions, and this discovery led to the completion of the present invention. That is to say, the present invention provides the following inventions. 1. An SnS dispersion liquid in which SnS particles are dispersed in a water- or alcohol-based dispersion liquid, wherein a mean major axis of the dispersed SnS particles is 100 nm to 2000 nm, a mean minor axis of the SnS particles is 50 nm to 1000 nm and a mean aspect ratio (major axis / minor axis) is 1.2 to 1.6. 2. The SnS dispersion liquid according to 1, wherein the concentration of the SnS particles in the water-based dispersion liquid is 0.0001 wt% to 50 wt%. 3. The SnS dispersion liquid according to 1, wherein a mean thickness of the SnS particles is 100 nm to 1000 nm and a particle size distribution (based on the scattering intensity, D50) of the SnS particles is in the range of 100 nm to 700 nm. 4. The SnS dispersion liquid according to 1, wherein the SnS purity of the dried SnS particles, as measured by XRD, is 90 wt% or more. 5. The SnS dispersion fluid according to 1, wherein a specific surface area of ​​the SnS particles measured by a BET measurement method is 5 m² 2 / g or more. 6. The SnS dispersion fluid according to 1, wherein a mass absorption coefficient (0.001 mass-%) 15,000 cm³ -1 or more at a wavelength of 600 nm. 7. SnS particles extracted from the SnS dispersion liquid according to 1, wherein a mean major axis of the SnS particles is 100 nm to 2000 nm, a mean minor axis of the SnS particles is 50 nm to 1000 nm and a mean aspect ratio (major axis / minor axis) is 1.2 to 1.6. 8. The SnS particles according to 7, wherein a mean thickness of the SnS particles is 100 nm to 1,000 nm and a particle size distribution (based on the scattering intensity, D50) of the SnS particles is in the range of 100 nm to 700 nm. 9. The SnS particles according to 7, wherein the SnS purity of the dried SnS particles, as measured by XRD, is 90 wt% or more. 10. The SnS particles according to 7, wherein a specific surface area of ​​the SnS particles is 5 m 2 / g or more, measured using a BET measurement method. 11. The SnS particles according to 7, wherein the SnS particles are mixed particles of SnS and acetylene black, which also contain acetylene black in addition to SnS. 12. A method for producing SnS particles, comprising: a step of gas phase deposition of heating an SnS raw material contained in an evaporation source vessel to retain SnS in a retention vessel, and an isolation step of separating the obtained product of the gas phase deposition from the retention vessel to obtain SnS particles, wherein in the gas phase deposition step a heating temperature of the evaporation source vessel is 700°C to 900°C and a maximum retention vessel temperature of 80°C to 130°C. 13. The method for producing SnS particles according to 12, wherein a mean retention rate in the gas phase deposition step is 20 mg / min or more. 14. A method for producing the SnS dispersion liquid according to 1, comprising: a gas phase deposition step of heating an SnS raw material contained in an evaporation source vessel to retain SnS in a retention vessel, an isolation step of separating the obtained gas phase deposition product from the retention vessel to obtain SnS particles, and a dispersion step of dispersing the gas phase deposition product obtained in the isolation step in a water- or alcohol-based dispersion liquid, wherein in the gas phase deposition step a heating temperature of the evaporation source vessel is 700°C to 900°C and a maximum retention vessel temperature of 80°C to 130°C. 15. The method for producing the SnS dispersion fluid according to 14, wherein the dispersion step includes an ultrasonic dispersion step of performing an ultrasonic dispersion with an amplitude of 50 µm to 150 µm. Advantageous effects of the invention

[0006] The SnS dispersion fluid of the present invention exhibits good dispersibility without precipitation during storage.

[0007] The SnS particles of the present invention constitute the SnS dispersion fluid of the present invention and can exhibit excellent properties. Furthermore, according to the method for producing an SnS dispersion fluid of the present invention, it is possible to produce a dispersion fluid of SnS particles that exhibits good dispersibility without precipitation during storage. According to the method for producing SnS particles of the present invention, it is possible to obtain SnS particles that constitute the aforementioned SnS dispersion fluid, which can exhibit excellent properties. Since the SnS particles obtained from the SnS dispersion fluid of the present invention can exhibit excellent properties, they are useful as raw materials in the energy sector, in the lubricant sector, etc. Brief description of the drawings [ Fig. 1] Fig.Figure 1 is a schematic diagram showing a gas phase deposition device for carrying out a step of gas phase deposition in the process for producing an SnS dispersion liquid of the present invention. [ Fig. 2] Fig. Figure 2 is a REM image (a photograph replacing a drawing) showing the particle state of SnS particles dispersed in the SnS dispersion fluid obtained in Example 1. [ Fig. 3] Fig. Figure 3 is a REM image (a photograph replacing a drawing) showing the particle state of SnS particles dispersed in the SnS dispersion fluid obtained in Example 2. [ Fig. 4] Fig. Figure 4 is a REM image (a photograph replacing a drawing) showing the particle state of SnS particles dispersed in the SnS dispersion fluid obtained in Example 3. [ Fig. 5] Fig.Figure 5 is a photograph replacing a drawing, showing the dispersion state of an SnS dispersion liquid. Figure 5 shows (a) the initial state of the SnS dispersion liquid obtained in Example 1, Figure 6 shows (b) the state of the SnS dispersion liquid obtained in Example 1 after 17 h, Figure 7 shows (c) the initial state of the SnS dispersion liquid obtained in Example 2, Figure 8 shows (d) the state of the SnS dispersion liquid obtained in Example 2 after 17 h, Figure 9 shows (e) the initial state of the SnS dispersion liquid obtained in Example 3, Figure 1 shows (f) the state of the SnS dispersion liquid obtained in Example 3 after 17 h, Figure 1 shows (g) the initial state of the SnS dispersion liquid obtained in the comparison example, and Figure 1 shows (h) the state of the SnS dispersion liquid obtained in the comparison example after 17 h. [ Fig. 6] Fig.Figure 6 is a REM image (a photograph replacing a drawing) showing the particle state of SnS particles dispersed in the SnS dispersion fluid obtained in the comparison example. [ Fig. 7] Fig. Figure 7 is a diagram showing the XRD measurement results of the SnS particles obtained in the examples and the comparison example. [ Fig. 8] Fig.Figure 8 is a photograph replacing a drawing, showing the dispersion state of the SnS dispersion liquid. Figure 8 shows (a) the initial state of the SnS dispersion liquid obtained in Example 4, (b) the initial state of the SnS dispersion liquid obtained in Example 5, (c) the initial state of the SnS dispersion liquid obtained in Example 6, (d) the initial state of the SnS-acetylene-black dispersion liquid obtained in Example 7, (e) the tin sulfide-acetylene-black mixed particles obtained in Example 7, (f) the initial state of the dispersion liquid obtained by redispersing the particles obtained in Example 7 in water, (g) the initial state of the SnS-acetylene-black dispersion liquid obtained in Example 8, and (h) the particles obtained in Example 9. Tin sulfide-acetylene black mixed particles,and (i) shows the initial state of the dispersion fluid obtained by redispersing the particles obtained in Example 8 in water. [ Fig. 9] Fig. Figure 9 is a diagram showing the particle size distribution of the SnS particles or SnS acetylene black particles obtained in Examples 4 to 8. [ Fig. 10] Fig. Figures 10(a) to 10(d) are SEM images (photographs replacing a drawing) showing the particle state of SnS acetylene black particles dispersed in the SnS dispersion liquids obtained in Examples 7 and 8 respectively. Description of the embodiments

[0008] The present invention is described in more detail below.<SnS-Dispersionsflüssigkeit und SnS-Teilchen> The SnS dispersion liquid of the present invention is an SnS dispersion liquid in which SnS particles are dispersed in a water- or alcohol-based dispersion liquid, and the mean particle diameter (mean of the principal axes) and the mean aspect ratio (principal / minor axis) of the dispersed SnS particles lie within specific ranges. Furthermore, the SnS particles of the present invention are obtained from the SnS dispersion liquid of the present invention, and their mean particle diameter (mean of the principal axes) and their mean aspect ratio (principal / minor axis) lie within specific ranges. The SnS particles of the present invention are extracted (removed) from the SnS particles that constitute the aforementioned SnS dispersion liquid and dried.

[0009] [SnS particles (SnS particles of the present invention)] In the present invention, the SnS particles dispersed in the SnS dispersion fluid (SnS particles of the present invention) have a mean major axis of 100 nm to 2000 nm, preferably 100 nm to 500 nm and most preferably 100 nm to 200 nm. The mean minor axis is also 50 nm to 1000 nm, preferably 50 nm to 200 nm and most preferably 50 nm to 150 nm. The mean aspect ratio (major axis / minor axis) is 1.2 to 1.6. Measurement methods for these are described in detail in the examples, but all can be measured using the SnS dispersion fluid. In other words, the SnS particles of the present invention are particles for which the mean major axis, mean minor axis and mean aspect ratio measured in the SnS dispersion fluid lie within the aforementioned ranges.It is assumed that, as a result of the mean principal axis, mean secondary axis, and mean aspect ratio lying within the aforementioned ranges, the dispersibility in the dispersion liquid is improved, and in turn, various aspects of the performance of the SnS particles themselves are enhanced to the required level. The mean principal axis is the mean diameter of the longest parts of the particles, and the mean secondary axis is the mean diameter of the shortest parts of the particles. Furthermore, the mean thickness of the SnS particles is preferably 100 nm to 1000 nm and more preferably 100 nm to 300 nm. The particle size distribution (based on the scattering intensity, D10) of the SnS particles is preferably in the range of 100 nm to 200 nm.The particle size distribution (based on the scattering intensity, D50) of the SnS particles is preferably in the range of 100 nm to 700 nm, more preferably 200 nm to 500 nm. The particle size distribution (based on the scattering intensity, D90) of the SnS particles is preferably in the range of 500 nm to 1500 nm. If the mean thickness and the particle size distribution (especially D50) are within the aforementioned ranges, the dispersibility is further improved and the required performance is enhanced. From the perspective of improving dispersibility, the specific surface area of ​​the SnS particles is preferably 5 m². 2 / g or more, preferably 5 m 2 / g up to 20 m 2 / g and most preferred 8 m 2 / g up to 15 m 2 / g, measured according to the BET method. The SnS particles of the present invention can be obtained by drying SnS particles dispersed in the SnS dispersion liquid. 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 wt% or more, and more preferably 95 wt% to 100 wt%. This purity can be achieved by the manufacturing process described below, which makes it possible to obtain a dispersion liquid with particles exhibiting excellent dispersibility and desired properties. A method for determining the SnS purity by XRD measurement is described in detail in the examples.Here, "dried" means a state in which the moisture has been removed from the SnS particles extracted from the dispersion liquid, and typically means a state in which the moisture content is 0.1 wt% or less. The moisture content can be measured using a conventional method without any particular limitations. Furthermore, the drying process can be carried out using a conventional method without any particular limitations, and drying can be carried out under reduced pressure at 50 °C to 100 °C for 1 h to 10 h using a vacuum dryer.In particular, SnS particles with a mean major axis of preferably 100 nm to 500 nm, more preferably 100 nm to 200 nm, a mean minor axis of preferably 50 nm to 200 nm, most preferably 50 nm to 150 nm, and a mean aspect ratio (major axis / minor axis) of 1.2 to 1.6 are considered to have excellent dispersibility and to be useful materials in various fields. Furthermore, it is particularly preferred that the mean thickness be 100 nm to 300 nm and that the particle size distribution (based on the scattering intensity, D50) be 200 nm to 500 nm. Such SnS particles can be obtained by extracting SnS particles from the SnS dispersion liquid obtained by an ultrasonic dispersion step in the manufacturing process described below, and drying the SnS particles as in the drying process described above.In this sense, it can be said that if the process for producing an SnS dispersion fluid includes an ultrasonic dispersion step, the process for producing the SnS dispersion fluid corresponds to a process for producing SnS particles.

[0010] 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 dioxide, silicon carbide, and the like. The form "contained" here includes a state in which SnS particles and other particles are simply dispersed and mixed, as well as a state in which particles of each type aggregate and the respective aggregates further aggregate, and a state in which particles of each type aggregate. In this case, the mixing ratio of the other particles is preferably 99 to 70 SnS : 1 to 30 other particles (weight ratio, total quantity 100).

[0011] [Water-based dispersion fluid] The water-based dispersion fluid used in the SnS dispersion fluid of the present invention can be water or a liquid mixture of water and a water-soluble organic solvent. The organic solvent can be an alcohol such as ethanol, isopropanol (IPA), and methanol, and the mixing ratio is not particularly restricted in this case. [Alcohol-based dispersion fluid] The alcohol-based dispersion fluid used in the SnS dispersion fluid of the present invention can be ethanol, isopropanol (IPA), methanol, and the like.

[0012] [SnS dispersion fluid] The concentration of the SnS particles (including in the case where other particles are present) in the water-based dispersion fluid is preferably 0.0001 wt% to 50 wt%, more preferably 0.0001 wt% to 25 wt%, even more preferably 0.001 wt% to 20 wt%, and most preferably 0.01 wt% to 10 wt%. If the concentration is below these ranges, it can be difficult to maintain the properties of the SnS particles. It is also preferred that these ranges are not exceeded, as dispersibility may decrease, leading to particle aggregation and a decrease in particle performance. The light absorption of the dispersion liquid 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.Furthermore, the mass absorption coefficient of the dispersion liquid (0.001 mass %) is preferably 15,000 cm. -1 or more and stronger, preferably 50,000 cm² -1 up to 80,000 cm -1 at a wavelength of 600 nm. The light absorption, transmittance, and mass absorption coefficient mentioned above all refer to an SnS particle concentration of 0.001 wt%, and for improved dispersibility, it is preferred that these properties lie within the aforementioned ranges. The measurement methods are as described in the examples. At an SnS particle concentration of 5 wt%, the light absorption 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 preferably 25 cm⁻¹. -1or more and stronger, preferably 50 cm -1 up to 80 cm -1 .

[0013] <Verfahren zur Herstellung einer SnS-Dispersionsflüssigkeit und Verfahren zur Herstellung von SnS-Teilchen> Next, methods for producing the SnS dispersion liquid and the SnS particles of the present invention are described above. The method for producing SnS particles of the present invention can be carried out by performing a gas-phase deposition step of heating the SnS raw material contained in an evaporation source vessel to retain the SnS in a retention vessel, and an isolation step of separating the resulting gas-phase deposition product from the retention vessel to obtain SnS particles.This manufacturing process can yield the SnS particles forming the SnS dispersion liquid of the present invention described above, but the SnS particles that are particularly preferred among the SnS particles of the present invention described above can be obtained by carrying out the process for preparing the SnS dispersion liquid described below, then drying the SnS dispersion liquid obtained and extracting (removing) the SnS particles from the SnS dispersion liquid.Furthermore, the manufacturing process of the SnS dispersion liquid of the present invention is also a method for producing the SnS dispersion liquid described above and can be carried out by performing a gas-phase deposition step of heating the SnS raw material contained in an evaporation source vessel to retain SnS in a retention vessel, an isolation step of separating the resulting gas-phase deposition product from the retention vessel to obtain SnS particles, and a dispersion step of dispersing the gas-phase deposition product obtained in the isolation step in a water-based dispersion liquid. The gas-phase deposition step and the isolation step are common to both the method for producing SnS particles and the method for producing an SnS dispersion liquid.In other words, the process for producing an SnS dispersion liquid can be carried out by adding the dispersion step to the process for producing SnS particles. Therefore, the following explanation of the process for producing SnS particles also applies to the process for producing an SnS dispersion liquid.

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

[0015] [Vacuum phase deposition step] The vapor phase deposition step is a step of heating the SnS raw material contained in an evaporation source vessel and retaining the SnS in a retention vessel and can be carried out using the in Fig.The gas phase separation device shown in 1 is used. Fig.The vapor deposition device 1 shown in Figure 1 is equipped with a chamber 10, which can be sealed and evacuated, a heating device 20 installed in the chamber 10, an evaporation source vessel 30, and a retention vessel 40. The evaporation source vessel 30 is configured to accommodate an evaporation source inside, and a thermometer (not shown) is installed in this evaporation source vessel 30 so that the temperature can be measured. The evaporation source vessel 30 can be heated by the heating device 20. The retention vessel 40 is installed at a predetermined distance from the evaporation source vessel 30, and a thermometer (not shown) is installed in it so that the temperature can be measured.Any container normally used in this type of vapor deposition apparatus can be used without special restrictions as a heating device, evaporation source vessel, and retention vessel. For example, the retention vessel can be made of glass, such as borosilicate glass, or metal, such as aluminum oxide, as long as it is heat-resistant and does not modify the SnS particles deposited from the gas phase. Although not shown in the figure, chamber 10 is connected to a vacuum pump to reduce the pressure and maintain a vacuum, and is also equipped with a valve to return the reduced pressure to normal pressure. A standard thermocouple or similar device can be used as a thermometer, which is not shown in the figure.There are no particular restrictions on the temperature measurement point, but it is preferred to measure the temperature near the side of the evaporation source vessel, as this reduces the influence of the heating device, and for the same reason, it is preferred to measure the temperature on the rear side of the retention surface in the retention vessel. In the vapor deposition step, the heating temperature of the evaporation source vessel 30 (the temperature measured by the thermometer) is 700 °C to 900 °C, and the maximum retention vessel temperature of the retention vessel 40 (the maximum temperature among the measured temperatures based on the temperature anomaly) is 80 °C to 130 °C. If the aforementioned temperatures are outside these ranges, the SnS dispersion fluid of the present invention described above cannot be produced. The retention vessel 40 is installed at a predetermined distance from the evaporation source vessel 30.This distance is important for setting the maximum retention temperature of the retention vessel 40 and must be changed depending on the size of chamber 10 and the quantity of SnS raw material, but the maximum retention temperature can be set by adjusting this distance. In the vapor deposition step, it is preferred that the mean retention rate be 20 mg / min or more to obtain a dispersion liquid of better quality. The vapor deposition step ends when the SnS raw material, which is the evaporation source, is exhausted in the evaporation source vessel 30. It is preferred to maintain the pressure during the treatment at 5 Pa to 1 × 10⁻⁶. -5 To keep pa.

[0016] [Isolation Step] The isolation step is a step of separating the obtained product of the vapor deposition from the collection vessel to obtain SnS particles. In particular, this step can be carried out by mechanically peeling and collecting the SnS particles in the collection vessel 40. This peeling and collection can be carried out, without any particular restrictions, using any conventional method that can be employed when particles are produced by vapor deposition and the produced particles are isolated and recovered. Additionally, in this step, the SnS particles adhering to the collection vessel can also be isolated and recovered by reconstructing them in a volatile solvent such as ethanol. By obtaining an ethanol dispersion liquid in which the particles are thus dispersed, the loss of SnS particles due to scattering during collection can be reduced.In the case of simple mechanical peeling and collection of the SnS particles, the resulting SnS particles can be obtained as they are. In the case of reconstructing the particles using a volatile solvent, the volatile solvent can be removed and the SnS particles dried to obtain SnS particles. Additionally, an SnS dispersion liquid can be obtained by performing a dispersion step described below.

[0017] [Dispersion Step] The dispersion step is necessary to carry out the process for producing the SnS dispersion liquid of the present invention. In this step, the SnS particles obtained as a product of gas-phase deposition in the isolation step are added to the water- or alcohol-based dispersion liquid, and the SnS particles are dispersed by a conventional method to obtain the SnS dispersion liquid of the present invention. Additionally, an ultrasonic dispersion step can be carried out in the dispersion step of the present invention, in which the ultrasonic dispersion is preferably performed at an amplitude of 50 µm to 150 µm, more preferably 100 µm to 130 µm.The ultrasonic dispersion step can be performed using an ultrasonic device commonly used for dispersion, such as an ultrasonic homogenizer, and the frequency can be freely selected from 20 Hz to 60 Hz. By performing the ultrasonic dispersion step with an amplitude in the aforementioned range, an SnS dispersion fluid with even better dispersibility can be obtained. Furthermore, if an SnS dispersion fluid containing the aforementioned other particles is obtained, it can be mixed with other particles, such as acetylene black particles, and the aforementioned dispersion (ultrasonic dispersion step as needed) can be repeated to obtain an SnS dispersion fluid containing these additional particles.In this case, the SnS particles obtained when the particles are extracted are SnS particles that contain the other particles.

[0018] [Other Steps] In addition to the above-mentioned steps of vapor deposition, isolation, and dispersion, other steps can be carried out in the present invention without departing from the spirit of the present invention. Since the SnS particles of the present invention are obtained by extracting (removing) the SnS particles that constitute the SnS dispersion liquid, a drying step must be carried out, for example, in which the SnS dispersion liquid is dried to obtain SnS particles. This drying step can vary in temperature and time depending on the quantity of SnS particles to be dried, but can, for example, be carried out by drying at 50 °C to 100 °C under reduced pressure for 1 h to 10 h using a vacuum dryer. Examples

[0019] The present invention is explained in more detail below with reference to examples and a comparative example, but the present invention is not limited to these.

[0020] [Example 1] The above-mentioned step of vapor deposition was performed using the in Fig. The vapor deposition process was carried out using the vapor deposition apparatus shown in Figure 1. A total of 13 g of bulk tin sulfide (with a purity of approximately 98%) was placed as raw material into the evaporation source vessel 30. The distance between the evaporation source vessel 30 and the retention vessel 40 was set to 12.3 cm. Next, the interior of the chamber was pressurized to a pressure in the range of 5 × 10⁻⁶ using a vacuum pump. -4The system was evacuated, and the temperature of the evaporation source vessel was raised to 900 °C using a heating device. The vessel was heated at 900 °C for 4 hours. The maximum temperature of the retention vessel 40 was 101 °C. The pressure during processing was 5 × 10 -3 Pa to 1 × 10 -4 Pa. The mean retention velocity measured according to the above-mentioned measurement method was 46.7 mg / min. Next, the isolation step and the dispersion step were carried out.

[0021] First, the holding container 40 was removed from the vacuum chamber 1. Ethanol was poured into the holding container 40, and SnS (hereinafter also referred to as "tin sulfide") was peeled off the glass container to obtain a tin sulfide-ethanol solution. The ethanol was removed from the resulting tin sulfide-ethanol solution. This removal was carried out as an isolation step by drying the tin sulfide-ethanol solution under reduced pressure in a vacuum dryer (drying temperature 70 °C, 4 h). Pure water was added to 0.4 g of the dried tin sulfide, and stirring was carried out by a conventional stirring method (stirring with a stirrer) to obtain 8 g of a 5 wt% aqueous tin sulfide solution (SnS dispersion liquid of the present invention).The SnS particles in the obtained dispersion liquid were dried to obtain SnS particles, and the following tests were carried out using the obtained tin sulfide. A photograph of the particle shape is shown in [reference]. Fig. 2 shown, the XRD results in Fig. 7 and other results in Table 1.

[0022] A precipitation test was performed using the obtained SnS dispersion fluid. The storage container was thoroughly stirred by hand before the start of the precipitation test. The precipitation test was carried out by checking the precipitation state at the beginning and after 17 hours. The results are presented in the Fig. 3(a) and Fig.3(b) shown. The following measurements were also carried out using the obtained SnS dispersion fluid. The results are shown in Table 1. Particle size distribution measurement and zeta potential measurement: the solvent used was pure water, which was the same solvent as that used for the SnS dispersion fluid, and the SnS dispersion fluid was diluted to 0.001 wt% to carry out the measurements. Additionally, the obtained SnS dispersion fluid (concentration 5 wt%) was used for measurements as is. The particle size distribution measurement was carried out using the "Litesizer (registered trademark) 500" particle size distribution analyzer from Anton Paar GmbH. The measurement method used was the dynamic light scattering method; the particle size distribution was measured based on the scattering intensity, and D10, D50, and D90 were calculated.Following the particle size distribution measurement, the zeta potential measurement was also performed using the same apparatus. The pH at the time of measurement was 7. Absorption and transmittance: The resulting SnS dispersion liquid (5 wt%) and the dilute solution obtained by diluting this dispersion liquid (5 wt%) with pure water to 0.001 wt% were used to perform measurements with a UV-Vis 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 Lambert-Beer law. The formula is given below. Mass absorption coefficient (cm²) -1 ) = Absorption / (Tin sulfide mass fraction × optical path length of the cell (cm)) Transmittance (%) = 10 -(Absorption)× 100. The results are shown in Table 1. A small amount of the obtained SnS dispersion liquid was dripped onto a measuring substrate. This was heated at 70 °C for 4 h under reduced pressure to remove moisture, and tin sulfide particles were obtained. Fig.Figure 2 shows an image of tin sulfide particles taken with a field emission scanning electron microscope (FE-SEM) (JSM-6500F, manufactured by JEOL Ltd.), and Table 1 shows the dimensions of the major axis A and the minor axis B of the tin sulfide particles obtained from the image. In addition, the thickness dimension L was measured with a laser microscope (product name KEYENCE VK-9700, manufactured by Keyence Corporation). A and B were obtained by visually capturing approximately 50 particles from the image and averaging the results. The SnS dispersion liquid was dried under reduced pressure in a vacuum dryer. The drying temperature was set to 70 °C, and the drying time was approximately 4 h. After completion of the drying process, the tin sulfide (SnS) powder of the present invention was obtained.The obtained tin sulfide powder was used to identify the tin sulfide powder using an X-ray diffraction device "XRD" (product name "Empyrean", manufactured by Malvern Panalystical Inc.). The measurement results are in . Fig. Figure 7 shows that no peaks other than tin sulfide were detected, so the purity of the tin sulfide was considered to be 99% by mass or greater. Next, the specific surface area was measured (using a specific surface area / pore distribution meter, product name "BELSORP-max," manufactured by Microtrack Bell Co., Ltd.) using the BET measurement method. The results are shown in Table 1.

[0023] [Comparative Example] The amount of bulk tin sulfide (purity approx. 98%) was 1.7 g, the heating temperature was 900 °C for 3 h, and the distance between the holding tank 40 and the evaporation source tank 30 was 3.8 cm. Then, except that the maximum temperature of the holding tank 40 was 199 °C, the vapor deposition highland step was carried out in the same manner as in Example 1. In addition, the dispersion step was carried out in the same manner as in Example 1, and an SnS dispersion liquid was obtained. The obtained SnS particles and the SnS dispersion liquid were subjected to the same tests and measurements as in Example 1. The results are shown in the Fig. 5, Fig. 6 and Fig. 7 and shown in Table 1.

[0024] [Example 2] An SnS dispersion fluid was prepared, and the tests and measurements were performed in the same manner as in Example 1, except that in addition to the usual stirring, the following ultrasonic dispersion step was performed in the dispersion step. In the ultrasonic dispersion step, the resulting 5 wt% SnS dispersion fluid was dispersed for 50 min at a frequency of 20 kHz and an amplitude of 60 µm using an ultrasonic homogenizer (ultrasonic homogenizer, product name “Q125”, manufactured by QSONICA LLC). The results are shown in the Fig. 3, Fig. 5 and Fig.7 and shown in Table 1. [Example 3] An SnS dispersion fluid was obtained in the same way as in Example 2, except that the frequency was 20 kHz and the amplitude was 120 µm. The obtained SnS dispersion fluid was subjected to the tests and measurements in the same way as in Example 1. The results are shown in the Fig. 4, Fig. 5 and Fig. 7 and Table 1 shown.

[0025] In Table 1, “%” means “mass %”. TABLE 1 Temperature-gas phase deposition source Maximum retention tank temperature Average deposition rate Ultrasound amplitude Ultrasound exposure time Particle size n=50 Particle size distribution related to scattering intensity Zeta potential Main axis A Secondary axle B AB ratio A / B Thickness L D10 D50 D90 (D90-D10) / D50 PH=7 (°C) (°C) (mg / min) (µm) (min) (nm) (nm) (nm) (nm) (nm) (nm) (mV) Example 1 700900 101 46.7 - - 1425.5 774.3 1.57 524 167.2 570.1 1154.3 1.73 -42.0 Example 2 60 50 272.9 179.3 1.58 201 112.9 264 931.4 3.10 -49.0 Example 3 120 50 143 103.8 1.38 148 123 248 543.2 1.69 -44.1 Comparative example 199 10.4 - - 2577.1 1567.5 1.65 1356 566 1503.9 4073.9 2.33 -45.0 Light absorption concentration 5% Light absorption ratio concentration 5% Light absorption concentration 0.001% Light absorption ratio concentration 0.001% Transfer concentration 5% Transmission concentration 0.001% Mass absorption coefficient concentration 5% Mass absorption coefficient concentration 0.001% Specific surface area (m²) 2 / G) Precipitation test concentration 5% Wavelength 600 nm Wavelength 1250 nm Wavelength 600 nm / 1250 nm Wavelength 600 nm Wavelength 1250 nm Wavelength 600 nm / 1250 nm Wavelength 600 nm (%) Wavelength 600 nm (%) Wavelength 600 nm (cm) -1 ) Wavelength 600 nm (cm) -1 ) 0h 17h Example 1 1.308 0.912 1.435 0.161 0.121 1.325 4.92 1 69.08 26.2 16063.1 7.5 no precipitation no precipitation Example 2 2.792 2.352 1.187 0.578 0.429 1.346 0.16 26.43 55.8 57790.3 10.0 no precipitation no precipitation Example 3 3.432 2.705 1.268 0.789 0.523 1.510 0.04 16.25 68.6 78919.6 11.0 no precipitation no precipitation Comparative example 0.96 0.537 1.788 0.147 0.075 1.955 10.96 71.22 19.2 14739.7 2.3 no precipitation Precipitation

[0026] As from the in Fig.As can be seen from the results shown in Figure 5, the SnS dispersion fluid of the present invention exhibits excellent dispersibility, with no precipitation occurring even after 17 hours. In contrast, the dispersion fluid of the comparison example has poor dispersibility, with precipitation occurring over time. Therefore, the SnS particles of the present invention have such excellent dispersibility that they are expected to exhibit excellent properties in various applications. [Example 4]

[0027] Pure water was added to 0.8 g of the dried tin sulfide obtained in the same manner as in Example 1, and stirring was carried out by a normal stirring procedure (stirring with a stirrer) to prepare 8 g of a 10 wt% aqueous tin sulfide solution (SnS dispersion liquid).

[0028] The resulting SnS dispersion fluid was dispersed for 90 minutes using an ultrasonic homogenizer (ultrasonic homogenizer, product name “Q125”, manufactured by QSONICA LLC) at a frequency of 20 kHz and an amplitude of 120 µm to obtain the SnS dispersion fluid of the present invention (the resulting dispersion fluid is in Fig. 8(a) shown).

[0029] The resulting SnS dispersion liquid was used to measure the particle size distribution. The solvent used was pure water, the same solvent as in the SnS dispersion liquid, and the SnS dispersion liquid was diluted to 0.001 wt% for the measurement. The particle size distribution was measured using the "Litesizer (registered trademark) 500" particle size distribution analyzer from Anton Paar GmbH. The measurement method used was dynamic light scattering; the particle size distribution was measured based on the scattering intensity, and D10, D50, and D90 were calculated. The results obtained are shown in Table 2. Fig. 9 shown. [Example 5]

[0030] Pure water was added to 1.6 g of the dried tin sulfide obtained in the same manner as in Example 1, and stirring was carried out by a conventional stirring procedure (stirring with a stirrer) to prepare 8 g of a 20 wt% aqueous tin sulfide solution (SnS dispersion liquid).

[0031] Using an ultrasonic homogenizer (ultrasonic homogenizer, product name “Q125”, manufactured by QSONICA LLC), the resulting SnS dispersion fluid was dispersed for 90 min at a frequency of 20 kHz and an amplitude of 120 µm to obtain the SnS dispersion fluid of the present invention (the resulting dispersion fluid is in Fig. 8(b) shown).

[0032] The resulting SnS dispersion liquid was used to measure the particle size distribution. The solvent used was pure water, the same solvent as in the SnS dispersion liquid, and the SnS dispersion liquid was diluted to 0.001 wt% for the measurement. The particle size distribution was measured using the "Litesizer (registered trademark) 500" particle size distribution analyzer from Anton Paar GmbH. The measurement method used was dynamic light scattering; the particle size distribution was measured based on the scattering intensity, and D10, D50, and D90 were calculated. The results obtained are shown in Table 2. Fig. 9 shown. [Example 6]

[0033] Isopropyl alcohol (special purified 2-propanol, manufactured by Kanto Chemical Co., Ltd.) was added to 1.6 g of the dried tin sulfide obtained in the same manner as in Example 1, and stirring was carried out by a conventional stirring procedure (stirring with a stirrer) to prepare 8 g of a 20 wt% tin sulfide isopropyl alcohol solution (SnS-IPA dispersion liquid, obtained by dispersing SnS in IPA).

[0034] The resulting SnS-IPA dispersion fluid was dispersed for 90 minutes using an ultrasonic homogenizer (ultrasonic homogenizer, product name “Q125”, manufactured by QSONICA LLC) at a frequency of 20 kHz and an amplitude of 120 µm to obtain the SnS dispersion fluid of the present invention. The resulting dispersion fluid is in Fig. 8(c) shown.

[0035] The resulting SnS-IPA dispersion was used to measure the particle size distribution. The solvent used was isopropyl alcohol, the same solvent as in the SnS-IPA dispersion, and the SnS-IPA dispersion was diluted to 0.001 wt% for measurement. The particle size distribution was measured using the "Litesizer (registered trademark) 500" particle size distribution analyzer from Anton Paar GmbH. The measurement method used was dynamic light scattering; 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. Fig. 9 shown. [Example 7]

[0036] The same operations as in Example 6 were performed to obtain a 20 wt% SnS-IPA dispersion fluid.

[0037] Acetylene Black (DENKA BLACK Li Li-100 powder product, manufactured by Denka Co., Ltd., mean particle size: 35 nm, specific surface area: 68 m²) was tested separately. 2 / g, bulk density: 0.04 g / ml). This acetylene black was added to the 20 wt% SnS-IPA dispersion liquid, resulting in a tin sulfide to acetylene black ratio of 95:5, and dispersion and mixing were carried out for 1 h using ultrasonic waves (ASU-2 ultrasonic cleaner, manufactured by As One Co., Ltd., oscillator circuit: separately excited type, high-frequency output: 40 W, oscillation frequency: 42 kHz) to produce a tin sulfide-acetylene black mixed dispersion liquid (SnS dispersion liquid of the present invention, SnS and acetylene black concentration: 20.8 wt%). The results obtained are shown in Fig. 8(d) shown.

[0038] The resulting tin sulfide-acetylene black mixed dispersion liquid was heated at 70°C for 4 h under reduced pressure to remove moisture, and tin sulfide-acetylene black mixed particles were obtained. The obtained particles are in Fig. 8(e) shown.

[0039] Fig. Figure 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 Ltd., hereinafter referred to as SEM). Additionally, the tin sulfide-acetylene black mixed dispersion liquid was diluted to 0.01 wt%, dried in the same manner, and photographed with SEM to confirm the dispersion state of acetylene. The results are shown in Fig. 10(b) shown.

[0040] Furthermore, the obtained tin sulfide-acetylene black mixture particles were used to measure the particle size distribution. A total of 0.1 g of tin sulfide-acetylene black mixture particles was used, and pure water was added to prepare a 0.01 wt% aqueous dispersion, which was then measured. The particle size distribution was measured using the "Litesizer (registered trademark) 500" particle size distribution analyzer from Anton Paar GmbH. The measurement method used was dynamic light scattering; the particle size distribution was measured based on the scattering intensity, and D10, D50, and D90 were calculated. The results obtained are shown in Table 2. Fig. 9 shown.

[0041] A total of 0.5 g of tin sulfide-acetylene black mixture particles were used, pure water was added, and stirring was carried out using a standard stirring procedure (stirring with a stirrer) to produce a 1 wt% tin sulfide-acetylene black aqueous dispersion, and the dispersion state in pure water was confirmed. The results are presented in Fig. 8(f) shown. [Example 8]

[0042] The same operations as in Example 6 were performed to obtain a 20 wt% SnS-IPA dispersion fluid.

[0043] Acetylene black was added to the 20 wt% SnS-IPA dispersion liquid, resulting in a tin sulfide to acetylene black ratio of 90:10. Dispersion and mixing were carried out for 1 hour using ultrasonic waves to produce a tin sulfide-acetylene black mixed dispersion liquid (SnS dispersion liquid of the present invention, SnS and acetylene black concentration: 21.7 wt%). The resulting dispersion liquid is in Fig. 8(g) shown. Tin sulfide-acetylene-black mixed particles were obtained in the same way as in Example 7. The obtained particles are shown in Fig. 8(h) is shown. Additionally, 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 liquid was diluted to 0.01 wt%, dried in the same manner, and photographed with a SEM to confirm the dispersion state of acetylene. The results are shown in Fig. 10(d) shown. The particle size distribution was measured in the same way as in Example 7. The results are shown in Table 2 and Fig. 9 shown.

[0044] A total of 0.5 g of tin sulfide-acetylene black mixture particles were used, pure water was added, and stirring was carried out using a standard stirring procedure (stirring with a stirrer) to produce a 1 wt% aqueous tin sulfide-acetylene black mixture dispersion liquid, and the dispersion state in pure water was confirmed. The results are presented in Fig. 8(i) shown.

[0045] In Table 2, “%” means “mass %”. QUOTES INCLUDED IN THE DESCRIPTION

[0000] This list of documents cited by the applicant was automatically generated and is included solely for the reader's convenience. The list is not part of the German patent or utility model application. The DPMA accepts no liability for any errors or omissions. Cited patent literature

[0000] JP 08-144044

[0002] JP 2015-120607

[0002] JP 2018-5278

[0002] WO 2020 / 013191

[0002]

Claims

[1] An SnS dispersion liquid in which SnS particles are dispersed in a water- or alcohol-based dispersion liquid, wherein a mean major axis of the dispersed SnS particles is 100 nm to 2000 nm, a mean minor axis of the SnS particles is 50 nm to 1000 nm and a mean aspect ratio (major axis / minor axis) is 1.2 to 1.

6. [2] The SnS dispersion liquid according to claim 1, wherein the concentration of the SnS particles in the water-based dispersion liquid is 0.0001 wt% to 50 wt%. [3] The SnS dispersion fluid according to claim 1, wherein the mean thickness of the SnS particles is 100 nm to 1000 nm and the particle size distribution (based on the scattering intensity, D50) of the SnS particles is in the range of 100 nm to 700 nm. [4] The SnS dispersion liquid according to claim 1, wherein the SnS purity of the dried SnS particles as measured by XRD is 90 wt% or more. [5] The SnS dispersion fluid according to claim 1, wherein a specific surface area of ​​the SnS particles measured by a BET measurement method is 5 m 2 / g or more. [6] The SnS dispersion fluid according to claim 1, wherein a mass absorption coefficient (0.001 wt%) 15.000 cm³ -1 or more at a wavelength of 600 nm. [7] SnS particles extracted from the SnS dispersion liquid according to claim 1, wherein a mean major axis of the SnS particles is 100 nm to 2000 nm, a mean minor axis of the SnS particles is 50 nm to 1000 nm and a mean aspect ratio (major axis / minor axis) is 1.2 to 1.

6. [8] The SnS particles according to claim 7, wherein the mean thickness of the SnS particles is 100 nm to 1,000 nm and the particle size distribution (based on the scattering intensity, D50) of the SnS particles is in the range of 100 nm to 700 nm. [9] The SnS particles according to claim 7, wherein the SnS purity of the dried SnS particles as measured by XRD is 90 wt% or more. [10] The SnS particles according to claim 7, wherein a specific surface area of ​​the SnS particles is 5 m 2 / g or more, measured using a BET measurement method. [11] The SnS particles according to claim 7, wherein the SnS particles are mixed particles of SnS and acetylene black, which also contain acetylene black in addition to SnS. [12] A method for producing SnS particles, comprising: a step of vapor deposition of heating an SnS raw material contained in an evaporation source vessel to retain SnS in a retention vessel, and an isolation step of separating the obtained product of the vapor deposition from the retention vessel to obtain SnS particles, wherein in the vapor deposition step a heating temperature of the evaporation source vessel is 700°C to 900°C and a maximum retention vessel temperature of 80°C to 130°C. [13] The method for producing SnS particles according to claim 12, wherein the mean deposition rate in the gas phase deposition step is 20 mg / min or more. [14] A method for producing the SnS dispersion liquid according to claim 1, comprising: a gas phase deposition step of heating an SnS raw material contained in an evaporation source vessel to retain SnS in a retention vessel, an isolation step of separating the obtained gas phase deposition product from the retention vessel to obtain SnS particles, and a dispersion step of dispersing the gas phase deposition product obtained in the isolation step in a water- or alcohol-based dispersion liquid, wherein in the gas phase deposition step a heating temperature of the evaporation source vessel is 700°C to 900°C and a maximum retention vessel temperature of 80°C to 130°C. [15] The method for producing the SnS dispersion fluid according to claim 14, wherein the dispersion step includes an ultrasonic dispersion step of carrying out an ultrasonic dispersion with an amplitude of 50µm to 150µm.

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