Method of evaluating affinity between solid and solvent

Abstract

To provide a solid-solvent affinity evaluation method which can be applied to sample containing solids that easily settle.SOLUTION: A solid-solvent affinity evaluation method disclosed herein comprises a step of performing pulsed NMR measurement on a sample containing a solid and a solvent, where the pulsed NMR measurement is performed when the solid has settled in the solvent.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present invention relates to a method for evaluating the affinity between a solid and a solvent. [Background technology]

[0002] Solid materials (e.g., powders) can be mixed with solvents and other materials to be used as slurries. The mixability, dispersibility, and dispersion stability of solid materials affect product performance and defect rates, so these characteristics must be evaluated. Analysis of magnetic relaxation curves obtained by pulsed NMR (Nuclear Magnetic Resonance) measurements may be used for such evaluations.

[0003] Non-Patent Document 1 describes the application of solvent relaxation NMR in estimating the surface area and wettability of nanostructured carbon materials in solvents.

[0004] Patent Document 1 discloses a method for evaluating the mixed state of catalyst-supporting conductive particles and a polymer electrolyte in a catalyst ink for manufacturing electrodes for fuel cells. Patent Document 1 also discloses that the catalyst ink is measured by pulse NMR method, the polymer electrolyte is separated into a hard component with a short transverse (spin-spin) relaxation time (T2) and a soft component with a long relaxation time, and the mixed state is evaluated based on the abundance ratio of the hard component. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] JP 2009-301938 A [Non-patent literature]

[0006] [Non-Patent Document 1] D. Fairhurst et. al., Magn. Reson. Chem. 54, p.521-526 (2015). Summary of the Invention [Problem to be solved by the invention]

[0007] However, for example, solids with high true density or large particle size tend to settle in the slurry, which can cause the solid concentration in the detection area in the pulsed NMR measurement to change over time. In such cases, the total interfacial area between the solid and the solvent changes over time. Therefore, in the conventional technology, it was difficult to evaluate the affinity between the solid and the solvent in a sample containing a solid that tends to settle.

[0008] An object of one aspect of the present invention is to provide a method for evaluating the affinity between a solid and a solvent, which can be applied to samples containing solids that tend to settle. [Means for solving the problem]

[0009] In order to solve the above problems, a method for evaluating the affinity between a solid and a solvent according to one embodiment of the present invention includes a step of performing a pulsed NMR measurement on a sample containing the solid and the solvent, and the pulsed NMR measurement is performed in a state in which the solid is sedimented in the solvent. Effect of the Invention

[0010] According to one aspect of the present invention, it is possible to provide a method for evaluating the affinity between a solid and a solvent, which can be applied to a sample containing a solid that is prone to settling. [Brief description of the drawings]

[0011] [Figure 1] FIG. 1 is a diagram illustrating the concept of an evaluation method according to one embodiment of the present invention. [Diagram 2] FIG. 1 is a diagram showing the Rsp value of Example 1. [Diagram 3] FIG. 1 is a diagram showing the Rsp value of Comparative Example 1. [Figure 4] FIG. 13 is a diagram showing the Rsp value of Example 2. [Diagram 5] FIG. 13 is a diagram showing the Rsp value of Example 3. [Figure 6] FIG. 13 is a diagram showing the Rsp value of Example 4. [Figure 7] FIG. 13 is a diagram showing the Rsp value of Example 5. [Figure 8] FIG. 13 is a diagram showing the Rsp value of Example 6. [Figure 9] FIG. 13 is a diagram showing the Rsp value of Example 7. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0012] An embodiment of the present invention will be described below, but the present invention is not limited thereto. In this specification, unless otherwise specified, "A to B" representing a numerical range means "A or more and B or less."

[0013] [1. Method for evaluating the affinity between a solid and a solvent] A method for evaluating the affinity between a solid and a solvent according to one embodiment of the present invention includes a step of performing a pulsed NMR measurement on a sample containing the solid and the solvent, the pulsed NMR measurement being performed in a state where the solid is precipitated in the solvent. The method is also referred to simply as an evaluation method hereinafter.

[0014] The solid means a solid having a size that can be accommodated in a sample tube of a pulsed NMR apparatus together with a solvent. A solid larger than the sample tube may be crushed or classified to a size that can be accommodated in the sample tube. The solid may also have a size that can be dispersed in the solvent. Such solids include powders, particles, pellets, beads, wires, and the like.

[0015] The solvent can also be said to be a dispersion medium (liquid) for dispersing the solid. The state in which the solid has settled in the solvent means a state in which the solid has been deposited at the bottom of a sample tube containing the solid and the solvent. It can also be said to be a state in which a supernatant of the solvent is formed above the deposited solid. The state in which the solid has settled in the solvent is distinguished from a state in which the solid is uniformly dispersed in the solvent.

[0016] <1-1. Overview of evaluation method> According to the pulse NMR measurement, the relaxation time, which is an index of molecular mobility, can be obtained from the magnetic relaxation curve. Molecules with high mobility have long relaxation times, and molecules with low mobility have short relaxation times. If a solid with high affinity to the solvent is present in the sample, the interaction between the solvent molecules and the solid is strong, and many solvent molecules are restricted in their movement. In this case, the relaxation time is short. On the other hand, if a solid with low affinity to the solvent is present in the sample, the interaction between the solvent molecules and the solid is weak, and many solvent molecules are able to move freely. In this case, the relaxation time is long. The relaxation time is also long when only solvent molecules are present in the sample. For example, for a sample that is a dispersion liquid in which a solid is dispersed in a solvent, the Rsp value based on the following formula (1) can be used as an affinity index. Rsp = (relaxation time of the solvent alone - relaxation time of the dispersion) / relaxation time of the dispersion (1) The larger the Rsp value, the higher the affinity between the solid and the solvent.

[0017] Conventionally, when using pulsed NMR measurements, samples in which solids are uniformly dispersed in a solvent are used. In samples containing solids that do not easily settle, the solid concentration in the detection area in pulsed NMR measurements is uniform, making analysis based on the obtained magnetic relaxation curve easy. However, in samples containing solids that easily settle, the solid concentration in the detection area in pulsed NMR measurements can change over time, making analysis based on the magnetic relaxation curve difficult. For example, the difference in Rsp values ​​between low affinity and high affinity may become small, or the magnitude of the Rsp values ​​may be reversed between low affinity and high affinity.

[0018] In contrast, in the evaluation method according to one embodiment of the present invention, pulse NMR measurement is performed in a state where the solid is precipitated in the solvent. This allows the measurement to be performed in a state where the solid concentration in the detection area does not change, even for samples containing solids that tend to settle. In addition, as described below, the obtained magnetic relaxation curve can be separated into multiple components and analyzed. That is, in the conventional evaluation method, it was thought that a uniform dispersion liquid had to be evaluated, but the present inventors have found that the affinity of a sample containing a solid that tends to settle can be evaluated by evaluating the solid in a state where it is precipitated in a solvent.

[0019] FIG. 1 is a diagram for explaining the concept of an evaluation method according to one embodiment of the present invention. A sample containing only a solvent is called a blank, and a sample containing a solid and a solvent is called a mixed liquid. First, when a magnetic relaxation curve is obtained for a blank using a sample tube 10 to which a solvent 2 has been added, the magnetic relaxation curve contains only component B. This component B represents a component derived from solvent molecules with high mobility, and has a long relaxation time. In addition, when a magnetic relaxation curve is obtained for a mixed liquid using a sample tube 10 in which a solid 1 has been precipitated in a solvent 2, the magnetic relaxation curve can be waveform-separated into components A and B according to the length of the relaxation time. This component B represents a component derived from solvent molecules with high mobility, as in the case of measuring a blank, and has a long relaxation time. Therefore, in this case, component B is considered to be a component derived from the supernatant part in the sample tube, that is, solvent molecules that are not in contact with the solid. On the other hand, component A represents a component derived from molecules with lower mobility than component B, and has a short relaxation time. This component A is considered to be a component derived from solvent molecules whose mobility is restricted by the precipitated solid, that is, solvent molecules near the surface of the solid.

[0020] For example, for a sample in which a solid is precipitated in a solvent, the Rsp value based on the following formula (2) can be used as an affinity index. Rsp = (relaxation time of component B - relaxation time of component A) / relaxation time of component A (2) In this case, too, the larger the Rsp value, the higher the affinity between the solid and the solvent. High affinity can also contribute to the solid being easily mixed with the solvent, being easily dispersed, and being less likely to re-aggregate.

[0021] <1-2. Sample> The sample to be evaluated by the evaluation method includes a solid and a solvent. The solid is not particularly limited and may be an organic or inorganic substance. The organic substances include poorly soluble resins and polymers, specifically cellulose, carboxymethylcellulose (CMC), polytetrafluoroethylene (PTFE), polystyrene latex, polypropylene, polystyrene, etc. The inorganic substances include metals, semimetals, carbon materials, and oxides and metal nitrides thereof, specifically aluminum, copper, gold, titanium oxide, alumina, silica, zirconia, silicon nitride, aluminum nitride, carbon nanotubes, graphite, lithium nickel cobalt manganese oxide, etc.

[0022] The evaluation method is effective for solids that tend to settle, as described above. Examples of such solids include solids with a large average particle size and / or true density. The average particle size of the solid may be, for example, 0.1 μm or more, or 0.5 μm or more. The upper limit of the average particle size of the solid may be, for example, 5000 μm or less, 3000 μm or less, 1000 μm or less, 500 μm or less, or 110 μm or less. The average particle size can be measured by a laser diffraction method. The true density of the solid is, for example, 0.9 g / cm 3 or more, 1.0 g / cm 3 The upper limit of the true density of the solid is, for example, 23 g / cm 3 It may be less than 20 g / cm 3 It may be less than 15 g / cm 3 It may be less than 10 g / cm 3 The true density can be measured by a gas displacement method.

[0023] In conventional pulsed NMR measurements, the larger the total surface area of ​​the solid, the larger the Rsp value. When compared at the same weight concentration, solids with a large average particle size have a smaller total surface area than solids with a small average particle size, and the sensitivity is low in pulsed NMR measurements. In order to measure solids with a large average particle size with the same sensitivity as solids with a small average particle size, it is necessary to increase the concentration, but high concentrations make it difficult to handle. In addition, samples that have a wide particle size distribution and contain solids with large particle sizes have poor measurement reproducibility because the large particle size solids sink quickly. However, in the evaluation method according to one embodiment of the present invention, since the solids are deliberately measured in a state where they are settled in a solvent, it is applicable to samples that contain solids that are prone to settling and samples with a wide particle size distribution.

[0024] The solvent is not particularly limited, and may be water or an organic solvent. Examples of the organic solvent include alcohol solvents, ether solvents, ester solvents, ketone solvents, amine solvents, amide solvents, aromatic solvents, and sulfur atom-containing solvents. Specific examples of the solvent include ethanol, 2-propanol, 1-butanol, 1-pentanol, ethylene glycol monomethyl ether, ethylene glycol monoethyl ether, propylene glycol monomethyl ether acetate, propylene glycol monoethyl ether, N,N-dimethylformamide, N,N-dimethylacetamide, N-methyl-2-pyrrolidone, dimethyl sulfoxide, γ-butyrolactone, acetylacetone, cyclopentanone, cyclohexanone, 1-methylimidazole, dimethyl carbonate, dibutyl ether, mesitylene, and 1,2,3,4-tetrahydronaphthalene. From the viewpoint of increasing the accuracy of the measurement, it is preferable to use one type of solvent for one sample. In other words, it is preferable to avoid mixing two or more types of solvents.

[0025] The amount of solids in 100% by weight of a sample (solids concentration) is preferably 0.1 to 99% by weight, and more preferably 10 to 99% by weight. If it is within this range, the measurement sensitivity can be increased.

[0026] <1-3. Pulsed NMR Measurement> The evaluation method includes a step of performing pulse NMR measurement on a sample containing a solid and a solvent. The observation nucleus is preferably a 1H nucleus. The resonance frequency is preferably 10 MHz or more, more preferably 15 MHz or more, and even more preferably 20 MHz or more. The measurement temperature is preferably 20 to 30°C.

[0027] Although the spin-lattice relaxation time (longitudinal relaxation time, T1 relaxation time) and the spin-spin relaxation time (transverse relaxation time, T2 relaxation time) can be obtained by pulse NMR measurement, it is preferable to obtain the T2 relaxation time in the evaluation method. Examples of pulse sequences include the Hahn echo method, the solid echo method, the CPMG (Carr-Purcell-Meiboom-Gill) method, and the 90° pulse method, but the CPMG method and the Hahn echo method are preferable in the evaluation method. For example, it is preferable to use the Hahn echo method for samples with short relaxation times.

[0028] The evaluation method may include a step of analyzing the magnetic relaxation curve obtained by the pulse NMR measurement by performing waveform separation into a plurality of components. The plurality of components may be two or more components, or may be three or more components. The plurality of components may be obtained by performing waveform separation based on, for example, the length of relaxation time. The magnetic relaxation curve may be waveform separated into, for example, two components. Examples of the two components include a component with a short relaxation time and a component with a long relaxation time, as described in <1-1. Overview of the evaluation method>. This also makes it possible to calculate the Rsp value.

[0029] The evaluation method may include a step of precipitating the solid in the solvent before the pulsed NMR measurement. The method of precipitating the solid in the solvent is not particularly limited, and examples thereof include a method of mixing the solid with the solvent and then leaving it to stand, a method of centrifuging, a method of putting the solid in a sample tube and then adding a solvent, and the like.

[0030] The evaluation method may include a step of quantifying the affinity between the solid and the solvent. The affinity is represented by, for example, the above-mentioned Rsp value. The evaluation method may include a step of comparing the affinity in a plurality of samples.

[0031] The present invention is not limited to the above-described embodiments, and various modifications are possible within the scope of the claims. Embodiments obtained by appropriately combining the technical means disclosed in different embodiments are also included in the technical scope of the present invention.

[0032] An embodiment of the present invention may include the following features. <1> A method for evaluating the affinity between a solid and a solvent, the method comprising a step of performing a pulsed NMR measurement on a sample containing the solid and the solvent, the pulsed NMR measurement being performed in a state where the solid is sedimented in the solvent. <2> A step of analyzing the magnetic relaxation curve obtained by the pulse NMR measurement by waveform separation into a plurality of components, <1> The method according to <3> A step of quantifying the affinity between the solid and the solvent, <1> or <2> The method according to <4> precipitating the solid in the solvent prior to the pulsed NMR measurement; <1> ~ <3> 2. The method according to claim 1 , EXAMPLES

[0033] An embodiment of the present invention will now be described.

[0034] [Example 1] <Preparation of titanium oxide (rutile type) mixed solution> A solid sample (titanium oxide (rutile type) powder (average particle size 0.5 μm) 250 mg) and a solvent (0.5 mL) were added to a sample tube and mixed. After mixing, the solid sample settled and the solvent was left on the top, which was the test sample. This test sample is also called the mixed liquid. Separately, a sample tube containing only the solvent was also prepared.

[0035] The solvents used were dibutyl ether, 2-propanol, ethanol, N,N-dimethylformamide, mesitylene, 1-methylimidazole, dimethyl sulfoxide, dimethyl carbonate, γ-butyrolactone, 1,2,3,4-tetrahydronaphthalene, 1-butanol, ethylene glycol monomethyl ether, propylene glycol monomethyl ether acetate, propylene glycol monoethyl ether, N,N-dimethylacetamide, N-methyl-2-pyrrolidone, acetylacetone, cyclopentanone, or cyclohexanone.

[0036] Each sample tube was sealed and subjected to pulsed NMR measurement.

[0037] <Pulse NMR measurement conditions> Magnetic relaxation curves of the mixture and the solvent were obtained using a pulsed NMR apparatus under the following conditions.

[0038] Equipment: the minispec mq20 (Bruker) Observed nucleus: 1H nucleus (resonance frequency 20MHz) Pulse sequence: CPMG method (T2 measurement) ·Measurement temperature: 25℃ Number of repetitions: Solvent: 2 times ·Mixture: 5 times <Obtaining affinity index (Rsp value)> The relaxation time (Tb) of the solvent alone was obtained from the magnetic relaxation curve of the solvent. The magnetic relaxation curve of the mixed liquid was separated into two components based on the length of the relaxation time. Of the two separated relaxation times, the relaxation time of the shortest component was taken as the relaxation time (Ts) of the solvent near the surface of the solid sample.

[0039] In the process of separating the magnetic relaxation curve into two components and obtaining the relaxation time, analysis software (TD-NMR Analyze Software) attached to the pulse NMR device was used.

[0040] Using the two relaxation times obtained above, the Rsp value was calculated as [(Tb-Ts) / Ts]. The results are shown in Table 1 and Figure 2.

[0041] [Table 1]

[0042] [Comparative Example 1] <Preparation of titanium oxide (rutile type) dispersion> A solid sample (75 mg of titanium oxide (rutile type) powder (average particle size 0.5 μm)) and a solvent (1.5 mL) were added to a sample tube, mixed, and stirred by inversion to obtain a dispersion. This dispersion was used as the test sample. In this dispersion, the solid sample did not settle, and no supernatant solvent was produced. Separately, a sample tube containing only the solvent was also prepared.

[0043] The solvent used was the same as in Example 1. Each sample tube was sealed and subjected to pulsed NMR measurement.

[0044] <Pulse NMR measurement conditions> The magnetic relaxation curves of the dispersion and the solvent were obtained using a pulsed NMR device under the following conditions.

[0045] Equipment: the minispec mq20 (Bruker) Observed nucleus: 1H nucleus (resonance frequency 20MHz) Pulse sequence: CPMG method (T2 measurement) ·Measurement temperature: 25℃ Number of repetitions: Solvent: 2 times ·Dispersion liquid: 5 times <Obtaining affinity index (Rsp value)> The relaxation time (Tb) of the solvent alone was obtained from the magnetic relaxation curve of the solvent. The relaxation time (Ts) of the dispersion was obtained from the magnetic relaxation curve of the dispersion. The magnetic relaxation curve of this dispersion was not subjected to waveform separation into two components as in Example 1.

[0046] In the process of acquiring the relaxation time, the analysis software attached to the pulse NMR device (TD-NMR Analyze Software was used.

[0047] Using the two relaxation times obtained above, the Rsp value was calculated as [(Tb-Ts) / Ts]. The results are shown in Table 2 and Figure 3.

[0048] [Table 2]

[0049] [Example 2] <Preparation of titanium oxide (rutile type) mixed solution> A solid sample (150 mg of titanium oxide (rutile type) powder (average particle size 2.0 μm)) and a solvent (0.5 mL) were added to a sample tube and mixed. After mixing, the solid sample settled and the solvent was left on the top, which was used as the test sample. Separately, a sample tube containing only the solvent was also prepared.

[0050] The solvent used was the same as in Example 1. Each sample tube was sealed and subjected to pulsed NMR measurement.

[0051] <Pulse NMR measurement conditions> Magnetic relaxation curves of the mixture and the solvent were obtained using a pulsed NMR apparatus under the following conditions.

[0052] Equipment: the minispec mq20 (Bruker) Observed nucleus: 1H nucleus (resonance frequency 20MHz) Pulse sequence: CPMG method (T2 measurement) ·Measurement temperature: 25℃ Number of repetitions: Solvent: 2 times ·Mixture: 3 times <Obtaining affinity index (Rsp value)> As in Example 1, the relaxation time of the short-time component (Ts) and the relaxation time of the solvent (Tb) were obtained from the magnetic relaxation curve.

[0053] Using the two relaxation times obtained above, the Rsp value was calculated as [(Tb-Ts) / Ts]. The results are shown in Table 3 and Figure 4.

[0054] [Table 3]

[0055] [Example 3] Except for using 250 mg of titanium oxide (anatase type) powder (average particle size 0.6 μm) as a solid sample in the sample tube, the Rsp value=[(Tb−Ts) / Ts] was calculated in the same manner as in Example 2. The results are shown in Table 4 and FIG.

[0056] [Table 4]

[0057] [Example 4] The Rsp value=[(Tb−Ts) / Ts] was calculated in the same manner as in Example 2, except that 700 mg of copper powder (average particle size 1.0 μm) was used as a solid sample in the sample tube and the following solvents were used.

[0058] The solvents used were dibutyl ether, 2-propanol, ethanol, N,N-dimethylformamide, mesitylene, dimethyl sulfoxide, dimethyl carbonate, γ-butyrolactone, 1,2,3,4-tetrahydronaphthalene, 1-butanol, ethylene glycol monomethyl ether, propylene glycol monomethyl ether acetate, propylene glycol monoethyl ether, N,N-dimethylacetamide, N-methyl-2-pyrrolidone, cyclopentanone, or cyclohexanone.

[0059] The results are shown in Table 5 and FIG.

[0060] [Table 5]

[0061] [Example 5] <Preparation of alumina mixed liquid> A solid sample (200 mg of alumina powder (average particle size 51 μm)) and a solvent (0.4 mL) were added to a sample tube and mixed. After mixing, the solid sample settled and the solvent was left on the top, which was used as the test sample. Separately, a sample tube containing only the solvent was also prepared.

[0062] The solvents used were water, ethanol, 2-propanol, 1-butanol, 1-pentanol, ethylene glycol monoethyl ether, propylene glycol monoethyl ether, N,N-dimethylformamide, N,N-dimethylacetamide, dimethyl sulfoxide, 1-methylimidazole, dimethyl carbonate, dibutyl ether, or mesitylene.

[0063] Each sample tube was sealed and subjected to pulsed NMR measurement.

[0064] <Pulse NMR measurement conditions> Magnetic relaxation curves of the mixture and the solvent were obtained using a pulsed NMR apparatus under the following conditions.

[0065] Equipment: the minispec mq20 (Bruker) Observed nucleus: 1H nucleus (resonance frequency 20MHz) Pulse sequence: CPMG method (T2 measurement) ·Measurement temperature: 25℃ Number of repetitions: Solvent: 2 times ·Mixture: 3 times <Obtaining affinity index (Rsp value)> As in Example 1, the relaxation time of the short-time component (Ts) and the relaxation time of the solvent (Tb) were obtained from the magnetic relaxation curve.

[0066] Using the two relaxation times obtained above, the Rsp value was calculated as [(Tb-Ts) / Ts]. The results are shown in Table 6 and Figure 7.

[0067] [Table 6]

[0068] [Example 6] <Preparation of sodium carboxymethylcellulose (CMC) mixture> A solid sample (250 mg of CMC powder (average particle size 105 μm)) and a solvent (0.4 mL) were added to a sample tube and mixed. After mixing, the solid sample settled and the solvent was left on the top, which was used as the test sample. A separate sample tube containing only the solvent was also prepared.

[0069] The solvents used were ethanol, 2-propanol, ethylene glycol monoethyl ether, N,N-dimethylformamide, N,N-dimethylacetamide, N-methyl-2-pyrrolidone, dimethyl sulfoxide, γ-butyrolactone, cyclopentanone, 1-methylimidazole, dimethyl carbonate, dibutyl ether, or mesitylene.

[0070] Each sample tube was sealed and subjected to pulsed NMR measurement.

[0071] <Pulse NMR measurement conditions> Magnetic relaxation curves of the mixture and the solvent were obtained using a pulsed NMR apparatus under the following conditions.

[0072] Equipment: the minispec mq20 (Bruker) Observed nucleus: 1H nucleus (resonance frequency 20MHz) Pulse sequence: CPMG method (T2 measurement) ·Measurement temperature: 25℃ Number of repetitions: Solvent: 2 times ·Mixture: 3 times <Obtaining affinity index (Rsp value)> As in Example 1, the relaxation time of the short-time component (Ts) and the relaxation time of the solvent (Tb) were obtained from the magnetic relaxation curve.

[0073] Using the two relaxation times obtained above, the Rsp value was calculated as [(Tb-Ts) / Ts]. The results are shown in Table 7 and Figure 8.

[0074] [Table 7]

[0075] [Example 7] <Preparation of lithium nickel cobalt manganese oxide mixture> A solid sample (lithium nickel cobalt manganese oxide powder (average particle size 10 μm) 750 mg) and a solvent (0.5 mL) were added to a sample tube and mixed. After mixing, the solid sample settled and the solvent was left on the top, which was used as the test sample. A separate sample tube containing only the solvent was also prepared.

[0076] The solvents used were ethanol, 2-propanol, N,N-dimethylformamide, N,N-dimethylacetamide, N-methyl-2-pyrrolidone, dimethylsulfoxide, γ-butyrolactone, cyclopentanone, 1-methylimidazole, dibutyl ether, or mesitylene.

[0077] Each sample tube was sealed and subjected to pulsed NMR measurement.

[0078] <Pulse NMR measurement conditions> Magnetic relaxation curves of the mixture and the solvent were obtained using a pulsed NMR apparatus under the following conditions.

[0079] Equipment: the minispec mq20 (Bruker) Observed nucleus: 1H nucleus (resonance frequency 20MHz) Pulse sequence: Hahn echo method (T2 measurement) ·Measurement temperature: 25℃ Number of repetitions: Solvent: 2 times ·Mixture: 3 times <Obtaining affinity index (Rsp value)> As in Example 1, the relaxation time of the short-time component (Ts) and the relaxation time of the solvent (Tb) were obtained from the magnetic relaxation curve.

[0080] Using the two relaxation times obtained above, the Rsp value was calculated as [(Tb-Ts) / Ts]. The results are shown in Table 8 and Figure 9.

[0081] [Table 8]

[0082] Table 9 summarises the examples and comparative examples.

[0083] [Table 9]

[0084] In Comparative Example 1, where the test sample was mixed by inversion, the difference in Rsp value between each solvent was small, making it difficult to evaluate the affinity between the solid and the solvent. On the other hand, in Example 1, where the solid sample was allowed to settle, the tendency of solvents that make it difficult to disperse solid samples, such as dibutyl ether, mesitylene, dimethyl carbonate, γ-butyrolactone, 1,2,3,4-tetrahydronaphthalene, and propylene glycol monomethyl ether acetate, is the same as in Comparative Example 1, but the difference in Rsp value between each solvent was large, making it easy to evaluate the affinity between the solid and the solvent.

[0085] In Example 2, in which the amount of solid sample was reduced more than in Example 1, the difference in Rsp value when each solvent was used was larger than in Comparative Example 1. Furthermore, in Examples 3 to 7, in which the type of solid sample was changed, the difference in Rsp value when each solvent was used was larger than in Comparative Example 1. [Industrial Applicability]

[0086] The present invention can be used to evaluate the affinity between a solid and a solvent. [Explanation of symbols]

[0087] 1 solid 2. Solvent 10 Sample tube

Claims

1. A method for evaluating the affinity between a solid and a solvent, comprising the steps of: The method includes a step of performing a pulsed NMR measurement on a sample including the solid and the solvent; The method, wherein the pulsed NMR measurement is performed while the solid is sedimented in the solvent.

2. The method according to claim 1 , further comprising a step of analyzing the magnetic relaxation curve obtained by the pulsed NMR measurement by waveform separation into a plurality of components.

3. The method of claim 1 , further comprising the step of quantifying the affinity between the solid and the solvent.

4. The method of any one of claims 1 to 3, comprising the step of precipitating the solid in the solvent prior to the pulsed NMR measurement.

Images