KR20200080912A - Analysis method of dispersion stability using asymmetrical flow field-flow fractionation - Google Patents

Abstract

The present invention relates to a method for analyzing dispersibility of a dispersion by using asymmetrical flow field-flow fractionation. More specifically, the present invention relates to a method for analyzing dispersibility of a dispersion, which is capable of accurately analyzing a particle size by separating particles by a particle diffusion coefficient of the dispersion and the intensity of an external field, and analyzes the dispersibility of the dispersion by determining the uniformity of particle size distribution.

Description

{Analysis method of dispersion stability using asymmetrical flow field-flow fractionation}

The present invention relates to a dispersibility analysis method using an asymmetric flow field-flow fraction.

Carbon black is a pigment with high blackness, and is excellent in coloring, electric conductivity, weather resistance, chemical resistance, etc., and is widely used as a reinforcement and filler for plastics and elastomers, as a light blocking material for black matrix (BM), and high viscosity carbon black Dispersions are used in various fields such as color cosmetics, tires, rubber, color filter inks, paint and plastic industries.

However, carbon black has a problem that the primary particle diameter is fine and porous, the specific surface area is large, and the dispersion stability is low because the particles tend to aggregate due to strong affinity and low thermal stability. The size and shape of the carbon black particles greatly affect the color and physical properties of the product, and the aggregation of carbon black used as a pigment causes color changes and product defects. In addition, carbon black is very difficult to disperse in high concentration in water due to low wettability due to high viscosity and hydrophobic properties. Since the dispersing conditions affect the stability of the particles, it is very important to select a dispersing agent and a dispersing time. Carbon black has a problem in that it is difficult to select a stable dispersing agent and dispersing time in the process, and thus the application in the industry is limited.

In order to achieve stable dispersion of the pigment, the balance of the three components of the pigment, the solvent and the dispersant is important, and for the stabilization of the particles among the three components, the affinity of the carbon black and the dispersant is very important. This can be confirmed by density analysis, and SEM or DLS is generally used for density analysis. SEM has the advantage of being able to visually see the shape of the particles, but it has the disadvantage that it is difficult to confirm the particle size in the aqueous solution due to the analytical characteristics measured by drying the sample, while DLS can analyze the particle size in the aqueous solution, but the distribution of large particles When is small, it is difficult to check because the measurement is rare. As an example, Korean Patent Registration No. 10-1529178 discloses a method for evaluating the dispersibility of carbon black inside a carbon black dispersed organic solution, but the method can visually confirm the dispersibility of carbon black, but the particle size and distribution There are difficulties in confirmation. Therefore, it is necessary to optimize the dispersion time and stable dispersant in the production of the carbon black dispersion.

On the other hand, asymmetrical flow field-flow fractionation (asymmetrical flow field-flow fractionation) is a technology for separating nanoparticles using a separation velocity difference, which is easy to separate various analytes, and various detectors such as size or molecular weight. Since it is possible to obtain information of, it has been recently used for separation of nanoparticles. Accordingly, the present inventor has completed a method of analyzing the dispersibility of a dispersion liquid by analyzing the uniformity of particle distribution using an asymmetric flow field-flow fraction.

The present invention has been devised to solve the problems of the prior art as described above, and improves the accuracy of measuring the particle distribution of a dispersion using an asymmetrical flow field-flow fractionation. The purpose is to provide a method for dispersibility analysis.

The present invention to achieve the above object

1) injecting the dispersion into an asymmetrical flow field-flow fractionation (AF4) channel;

2) separating the dispersion according to particle size and separating over time;

3) detecting the separated particles with a detector;

4) collecting and inputting particle analysis information from the detector;

5) displaying the uniformity of the particle size distribution from the input information.

The detector includes an ultraviolet detector (UV-Vis), a differential refractometer (dRI), a multi angle light scattering (MALS), a dynamic light scattering (DLS), a fluorescence detector (FL), It is selected from Laser-Induced Breakdown Detection (LIBD), Inductively Coupled Plasma Mass Spectrometry (ICP-MS), and X-ray scattering.

The dispersion is characterized in that it comprises a carbon black dispersion.

The uniformity includes the step of calculating a sum of a value (a) representing a number of peaks and a value (b) representing a peak width in a graph showing the particle size distribution, and indicating that the higher the uniformity value is, the higher the dispersibility is. It is characterized by.

In the present invention, it is preferable to use a mixture of styrene and maleic acid in a ratio of 2:1 or more.

The dispersibility analysis method of the dispersion according to the present invention can accurately analyze the particle size, and can be usefully used to optimize the conditions for preparing the dispersion by analyzing the dispersion of the dispersion by determining the uniformity of the particle size distribution.

Figure 1 shows the pH measurement results of Examples 1 to 3 according to the milling time.
Figure 2 shows the electrical conductivity measurement results of Examples 1 to 3 according to the milling time.
Figure 3 shows the viscosity measurement results of Examples 1 to 3 according to the milling time.
Figure 4 shows the particle size measurement results of Examples 1 to 3 according to the milling time.
Figure 5 shows the SEM image measurement results of Examples 1 to 3 according to the milling time.
6 shows the results of particle size analysis according to milling time using DLS.
7 shows the results of particle size analysis according to the milling time using AF4.

Hereinafter, a method for analyzing dispersibility using an asymmetric flow field-flow fraction according to the present invention will be described in detail.

The method for analyzing the dispersibility of a dispersion according to the present invention includes: 1) injecting a dispersion into an asymmetrical flow field-flow fractionation (AF4) channel; 2) separating the dispersion according to particle size and separating over time; 3) detecting the separated particles with a detector; 4) collecting and inputting particle analysis information from the detector; 5) displaying the uniformity of the particle size distribution from the input information.

The asymmetrical flow field-flow fractionation (AF4) is a technique in which particles are separated by the diffusion coefficient of the particles and the intensity of the external field through the flow, and the asymmetric flow field-flow fractionation channel moves the dispersion liquid. Means empty space. The asymmetric flow-flow fraction forms a channel flow, a parabolic laminar flow, in which the flow velocity on both sides of the channel is slow and the flow velocity increases toward the center of the channel due to the frictional force formed while the fluid flows inside the channel. Another type of flow is a cross flow that flows vertically to a channel acted by an external field, and the particles are layered vertically in the channel according to the cross flow intensity, particle size, and diffusion coefficient, and diffusion occurs. The layered particles are separated according to the difference in the movement speed due to the parabolic laminar channel flow.

The detector is for obtaining information such as particle size, an ultraviolet detector (UV-Vis), a differential refractometer (dRI), a multi angle light scattering (MALS), and a dynamic light scattering ; DLS), Fluorescence (FL), Laser-Induced Breakdown Detection (LIBD), Inductively Coupled Plasma Mass Spectrometry (ICP-MS) and X-ray scattering It is preferred.

The dispersion is preferably a mixture of styrene and maleic acid, and is preferably mixed in a 1:1 to 4:1 weight ratio. In the present invention, commercially available SMA-1000 mixed with 1:1, SMA-2000 mixed with 2:1, and SMA-3000 mixed with 3:1 were used. More preferably, a mixture of 2:1 and 3:1 is used.

In addition, the dispersion in the present invention preferably includes a carbon black dispersion, but is not limited thereto. Since carbon black has a weak thermal stability and tends to easily aggregate, the dispersibility of the carbon black dispersion may be analyzed by the dispersibility analysis method according to the present invention to optimize dispersion conditions such as dispersant and dispersion time.

The uniformity is higher in uniformity as the number of peaks in the particle size distribution is smaller and the width of the peak is narrower. The lower the dispersibility, the more the particle size distribution is uneven and the particle size distribution is uneven because it has various particle sizes. The smaller the number of peaks in the particle size distribution, the more uniform the particle size, and the narrower the peak width, the more uniform the particle size.

Hereinafter, the present invention will be described in more detail with reference to Examples. However, the following examples are intended to illustrate the present invention, and the scope of the present invention is not limited thereto.

Example One

1) Dispersant synthesis

First, 42 g of SMA-1000 (Styrene maleic anhydride 1000, SARTOMER Co., Ltd., USA) and 42 g of purified water were added to a 3 neck flask, and the temperature of the solution was raised to 80°C while stirring. When the temperature of the solution was 80°C, 24 g of ammonia water (25-28%, DUKSAN, Korea) was added and stirred for 2 hours to prepare a dispersant.

2) Preparation of carbon black dispersion

After adding 75 g of the dispersant and 420 g of distilled water to 5 g of carbon black (SA, Bulk density, Alfa Aesar, USA), milling at 1500 rpm using a basket mill (HSX0502251, HYOSUNG, Korea) with 350 g of 0.8 mm beads. Carbon black dispersions were prepared by varying the time to 1 hour, 2 hours, and 3 hours, respectively.

Example 2

A carbon black dispersion was prepared in the same manner as in Example 1, except that SMA-2000 (Styrene maleic anhydride 2000, SARTOMER Co., Ltd., USA) was used as the dispersant.

Example 3

A carbon black dispersion was prepared in the same manner as in Example 1, except that SMA-3000 (Styrene maleic anhydride 3000, SARTOMER Co., Ltd., USA) was used as a dispersant.

The structures of the SMA dispersants synthesized in Examples 1 to 3 are as follows.

Experimental Example 1. Evaluation of aging stability

In order to evaluate the physical properties and stability of the carbon black dispersion according to the type of dispersant and milling time, pH, electrical conductivity, viscosity and particle size were analyzed for 11 days at 60°C for all examples, and all analyzes confirmed the reproducibility of the results. It was measured three times in order. pH is pH meter (OHAUS STARTER 2100, OHAUS Corp., USA), electrical conductivity is Conductivity meter (OHAUS STARTER 3100C, OHAUS Corp., USA), viscosity is Viscosity meter (LVDVE 230, Brookfield, USA), particle size and distribution Was measured using Dynamic Light Scattering (DLS; ELSZ-2000, Otsuka, Japan).

Figure 1 shows the pH of (a) Example 1, (b) Example 2, (c) Example 3 according to the milling time, Figure 2 (a) Example 1, (b) according to the milling time Example 2, (c) the electrical conductivity of Example 3, Figure 3 according to the milling time (a) Example 1, (b) Example 2, (c) Example 3 viscosity, Figure 4 milling It shows the particle size analysis of (a) Example 1, (b) Example 2, (c) Example 3 with time.

1 to 4 and Table 1 below, as a result of evaluating the elongation stability of the carbon black dispersion, the pHs and viscosities of Examples 1 to 3 were constant without significant changes. On the other hand, in Example 1, after 11 days, the electric conductivity value was 77.39% of the initial electric conductivity value, and as the electric conductivity tended to decrease the most, the carbon black and SMA 1000 dispersants confirmed that stable dispersion was difficult. .

milling
time 60℃, Day 11 pH Conductivity (㎲/㎝) Viscosity (cP) DLS (nm) Example 1 1 hours 8.46±0.39 572.50±117.85 1518.50±199.10 237.60±21.73 2 hours 8.43±0.42 592.50±127.92 1510.00±200.20 214.57±34.75 3 hours 8.45±0.39 577.00±111.87 1657.50±231.70 274.03±91.58 Example 2 1 hours 9.14±0.15 413.25±68.15 1617.50±357.90 204.47±51.85 2 hours 9.08±0.19 462.00±159.42 1445.00±214.20 177.53±6.56 3 hours 9.12±0.15 382.75±110.89 1492.50±241.00 204.30±42.35 Example 3 1 hours 9.14±0.15 304.25±66.64 1447.50±259.20 206.97±43.75 2 hours 9.08±0.19 294.25±74.79 1470.00±280.20 242.53±22.59 3 hours 9.12±0.15 288.75±84.48 1455.00±258.00 190.13±61.50

Experimental Example 2. Particle shape analysis

The image was analyzed using a field emission scanning electron microscope (FE-SEM; JEOL-7800F, JEOL Ltd., Japan) to confirm the shape and size of the carbon black in the carbon black dispersion. Figure 5 shows the SEM image of (a) Example 1, (b) Example 2, (c) Example 3 according to the milling time, the carbon black primary particle diameter of Examples 1 to 3 is 30-40 It was found to be ㎚, and existed as an irregularly shaped aggregate rather than a completely spherical aggregate.

Experimental Example 3. Particle size analysis using DLS and AF4

The particle size analysis was performed on the carbon black dispersion using Dynamic Light Scattering (DLS; ELSZ-2000, Otsuka, Japan) and AF4. For AF4, AF4 short channel (Wyatt Tech., Europe GmbH, Dernbach, Germany), cellulose membrane (Millipore, Bedford, USA) having a cut-off molecular weight of 10 kDa, 250 μm thick Mylar spacer was used, and AF4 was used. For separation, 0.1% FL-70 (fisher Chemical, USA) and 0.02% sodium azide (NaN ₃ , Sigma-Aldrich, USA) were used as the mobile phase. An HPLC pump (P-6000, FURECS Co., Ltd., Korea) was used for the injection of the mobile phase, and an Optiflow 1000 Liquid Flowmeter (Agilent Technologies, Palo Alto, CA, USA) was used for the flow rate measurement. In addition, a UV detector (Spectra SERIES UV 150, THERMO SEPARATION PRODUCTS, USA) was used to detect samples eluted by size. At this time, the channel flow was 0.8 ml/min, the cross flow was 0.3 ml/min, and the sample injection was 50 µl at 0.2 ml/min using a syringe pump (Legato 110, KD Scientific Inc., Mendon, USA). . All analyzes were measured three times to confirm the reproducibility of the results. The sample was subjected to a carbon black dispersion stored at 60°C for 11 days.

Figure 6 shows the particle size analysis of (a) Example 1, (b) Example 2, (c) Example 3 according to the milling time using DLS, Figure 7 of Examples 1 to 3 according to the milling time UV detector measurement results ((a), (c), (e)) and particle size analysis using AF4 ((b), (d), (f)) are shown.

Referring to FIG. 6 and Table 2, in Example 1, when the milling time was 3 hours, agglomeration proceeded by overdispersion, and through this, it was confirmed that the carbon black and the SMA 1000 dispersant were difficult to stably disperse. On the other hand, in Example 2, the particle size increased as the milling time increased, and in Example 3, the particle size decreased as the milling time increased, but there was no clear tendency in the type and dispersion time of the dispersant.

Particle size using DLS (60℃, Day 11) (nm) 1 hours 2 hours 3 hours Example 1 472.4±292.1 340.2±167.6 103.6±17.2
359.0±108.5 Example 2 256.8±66.1
1069.0±334.8 252.1±61.6 307.4±146.1 Example 3 110.2±17.2
390.2±111.4 291.1±121.0 239.9±58.2

Referring to Figure 7 and Table 3, AF4 measurement results, unlike DLS measurement results, Example 1 and Example 2 showed a tendency to decrease the particle size as the milling time increases, Example 3 the milling time As this increase, the size tended to increase.

Particle size using AF4 (60℃, day 11) (nm) 1 hours 2 hours 3 hours Example 1 290.90±7.91 295.17±7.71 286.44±8.54 Example 2 314.20±90.03 278.90±87.23 267.20±46.0 Example 3 273.80±22.93 275.10±25.27 294.53±7.03

Experimental Example 4. Color analysis

To further analyze the particle size of the carbon black dispersion, the color of the carbon black dispersion was analyzed using a color meter (CR-400 Chroma meter, Konica Minolta, USA). The color meter indicates information by digitizing L ^* (brightness), a ^* (redness), and b ^* (yellowness), which are shown in Table 4 below.

The L ^* value means brightness and brightness, and the smaller L ^* value is closer to black, which means the smallest particle size. As a result of the colorimeter measurement, Example 2 showed the smallest L ^* value when the milling time was 3 hours, and Example 3 showed the smallest L ^* value when the milling time was 1 hour. This confirms that the tendency of AF4 measurement result and size analysis are the same.

milling
time Color meter measurement data (60℃, day 11) L ^* a ^* b ^* Example 2 1 hours 24.33±0.00 0.34±0.03 0.08±0.02 2 hours 24.28±0.00 0.34±0.02 0.23±0.01 3 hours 23.89±0.00 0.33±0.04 0.28±0.02 Example 3 1 hours 23.26±0.01 0.38±0.06 0.23±0.02 2 hours 24.58±0.01 0.29±0.14 0.12±0.02 3 hours 24.11±0.01 0.31±0.03 0.25±0.02

Overall, SMA 1000 dispersant is considered to be further optimized for carbon black dispersion, SMA 2000 dispersant is 3 hours, SMA 3000 dispersant is 1 hour milling time, stable carbon black dispersion can be produced. Confirmed. As described above, while DLS has poor reproducibility when measuring the particle size of a high-viscosity carbon black dispersion, AF4 dispersibility of AF4 as the measurement results show the same tendency in the type and dispersion time of the dispersant as compared with the color meter measurement results. It can be seen that the analysis method is excellent.

The above description is merely illustrative of the present invention, and those skilled in the art to which the present invention pertains will be capable of various modifications without departing from the essential characteristics of the present invention. Accordingly, the embodiments disclosed herein are not intended to limit the present invention, but to explain the present invention, and the spirit and scope of the present invention are not limited by these embodiments. The scope of protection of the present invention should be interpreted by the following claims, and all technologies within the equivalent range should be interpreted as being included in the rights of the present invention.

Claims (6)

1) injecting the dispersion into an asymmetrical flow field-flow fractionation (AF4) channel;
2) separating the dispersion according to particle size and separating over time;
3) detecting the separated particles with a detector;
4) collecting and inputting particle analysis information from the detector;
5) displaying the uniformity of the particle size distribution from the input information; method for analyzing the dispersibility of the dispersion comprising the
The method of claim 1, wherein the detector is an ultraviolet detector (UV-Vis), a differential refractometer (dRI), multi-angle light scattering (MALS), dynamic light scattering (DLS), fluorescence detector (Fluorescence; FL), Laser-Induced Breakdown Detection (LIBD), Inductively Coupled Plasma Mass Spectrometry (ICP-MS) and X-ray scattering. Analysis method characterized by
The analysis method according to claim 1, wherein the dispersion comprises a carbon black dispersion.
The method of claim 1, wherein the uniformity comprises: calculating a sum of a value (a) representing a number of peaks and a value (b) representing a peak width in a graph representing a particle size distribution; the higher the sum, the higher the uniformity value. Analysis method characterized by displaying high
The analysis method according to claim 4, wherein the higher the uniformity value is, the higher the dispersibility is.
The method according to claim 1, wherein the dispersion is a mixture of styrene and maleic acid in a ratio of 2:1 or more.

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